v y-Z92^o rmmmm.: x-2n^^ 0\y Serial Added copy- Added vol. ;^':^^^s'^^oc? G^xntA V Type slips Oy^JtM^/j^J^ BIBLIOGRAPHIC CHECKmO RECORD Checker/ s 1^ Uj LC card no. /f-J^v^y-S f^C Main Stack Branch Spec. Printers Wyles ■ hi ^7 52 55 57 62 63 6ij- 65 66 67 68 LC X MJC \ \ Ja V Mr Ap My Je Jl Ag s N D UCB mi BNB BN Proof \_ — ■DTXTQ - V t\ S r. A SUPPLEMENT TO URE'S DICTIONARY OP ARTS, MANUFACTURES, AND MINES, CONTAINING A CLEAR EXPOSITION OF THEIR PRINCIPLES AND PRACTICE. FROM THE LAST EDITION, EDITED BY EGBERT HUNT, F.E.S., F.S.S., Keeper of Mining Records, Formerly Professor of Physics, Government School of Mines, &c., &c., ASSISTED BY NUMEROUS CONTRIBUTORS EMINENT IN SCIENCE AND FAMILIAR "WITH MANUFACTURES. ILLUSTRATED WITH SEVEN HUNDRED ENGEAVIlTGS ON TVOOD. NEW YORK: APPLETON AND COMPANY, 443 AND 445 BROADWAY. 1864. This Yoliime of lire's 2 Dictionary of Arts, Manufactures, and Mines, contains tiie additional knowledge wliicli has accumulated within the past ten years. ]^ot a year has passed but that some important improvements in the Arts and Sciences have taken place, all of which form an important increase to knowledge, which cannot well be dispensed with by those who are engaged in the various pursuits in which they are employed. The following are a few, among the many, who are specially interested, viz. : Artisans, Gunsmiths, Assayers, Gas Light Companies, Brewers, Glass Makers, Bakers, Hat Makers, Boiler Makers, Iron Mongers, Brass Founders, India Rubber Manufacturers, Bleachers, Ink Manufacturers, Brick Makers, Leather Dealers, Button Manufacturers, Miners, Chemists, Manufacturers, Coal Dealers, Plumbers, Calico Printers, Paper Manufacturers, Candle Makers, Photographers, Confectioners, Painters, Coppersmiths, Perfumers, Cotton Factories, Pyrotechnists, Carriage Makers, Eope Makers, Distillers, * Sliipping Merchants, Dyers, Sugar Refiners, Druggists, Silversmiths, Engineers, Soap Makers, Farmers, Tanners, Furriers, • Tobacconists, Founders, Weavers, Gold Beaters, TVine Growers, (fee, &c. , &c. PREFACE. Ure'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 prefoce 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- ino- : 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 pubhc 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 Ure'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 Ure'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 4 PEEFACE. 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 costmg §38, while the complete American edition of the work, in three volumes, comprising 3212 pages, with 2300 engravings, forms the com- jDletest repertory of arts, manufactures, and mines, Avhich has been yet published. Subjoined is a list of the contributors, whose initials will be found appended to their respective articles. Mr. Hunt avows the authorship of the rest. G. ANSELL, Esq., Rojal Mint. H. K. liAMBER, Esq.," F.C.S., &c. [E. W. BINNEY, Esq., F.G.S., &c., Manchester. H. W. BONE, Esq. Euameller, HENRY W. BRISTOW, Esq., F.G.S. Geo- logical Survey of Great Britain. R. J. 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'd Handbook. F. W. FAIRHOLT, Esq., F.R.A.S. Author of Costume in England, Dictionary of Terms in Art, &c. E. FRANKLAND, Esq., Ph.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 FRY'ER, Esq. Sugar Refiner, Man- chester. (TJie 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, d ACETIC ACID. 11 being kept all the while in constant agitation, and at the same time moved forward to the other end of the retort by means of an endless screw, s. By the time they ai-rive there, the charge has been completely carbonized, and all the pyroligneous acid evolved at the exit tube, t. The residuary charcoal falls through the pipe d into a vessel of water, e, whilst the v^Jkile products escape at f, and are condensed in the usual way. ^^everal of these retorts are generally set in a furnace side by side, the retorts are only 14 inches in diameter, and eigiit of these retorts produce in 24 hours as much acid as IG retorts 3 feet in diameter upon the old system. In the manufacturing districts of Lancashire and Yorkshire, where such immense quantities of spent dye-woods accumulate, and have proved a source of annoyance and expense for their removal, this process has afforded a most important means of economically converting them into valuable products — charcoal and acetic acid. Mention should also be made of Messrs. Solomons and Azulay's patent for employing superheated steam to effect the carbonization of the wood, which is passed directly into the mass of materials. Since the steam accompanies the volatile products, it necessarily dilutes the acid ; but this is in a great degree compensated for by employing these vapors to con- centrate the distilled products, by causing them to traverse a coil of tubing placed in a pan of the distillates. As regards the yield of acetic acid from the different kinds of wood, some valuable facts have been collected and tabulated by Stoize, in his work on Pyroligneous Acid : — Carbonate of One Pound of Wood. ■\Voislit of Acid. Potassa ncii- tralized by One Oiinceof Acid. TTciL'bt Suppose, for example, that the acid to be assayed is acetic acid, the instruc- tions given 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 ( = 50) 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 perfiictly 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 as.say. We shall terminate this article by a description of Liebig's acidimetrical method of determining tlie amount of prussic acid contained in solutions ; for example, in medicinal prussic acid, in laurel and liitter 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 friven by M. Violotto for the preparation of Sarcharnte of Limo are as follows: — Digest in the cold 50 grammes of slaked caustic lime in 1 litre of water containing 100 grammes of sugar. I 20 ACIPENSER. 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 cvanid'e of silver is produced, but it is immediately redissolved by shaking, because a double cyanide of silver and of potassium (Ag Cj -{- K Cy) is formed, which dissolves, v,-itbout 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 the 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 ( = 170) 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 \je used, as follows : — Take 63 grains of fused nitrate of silver, and dissolve them in 5,937 grains' weight of pure distilled water, makin"- alto"-ether 6,000 grains' weight of test silver solution. Weigh off now in a beaker any quantity, say 100, or, if very -n-eak, 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 bo 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 anhvdrous prussic acid. _ The rationale of these numbers is evident : since 1 cquiv. = 170 of nitrate of silver corresponds to 2 equiv. = 54 of prussic acid ; G3 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 :: 03 : 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 miTcury = 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. C"^" II" NO". A poisonous alkaloid constituting the active prmciple of the Aconite, Aconitwn Knpellus. — C. G. W. ACORNS. The seed of the oak {quercus). 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 plaut is a native of Enghind, ' growiiK' 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 fla^ is used by snutf-makers for scenting snufl", 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 thev bcnn 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. ACRYL AMINE or ALLYL AMINE. (C H' 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 d/crlv, a ray ; signifying merely the pmcer 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. i: a b 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 lie 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 ihe surfaces of bodies which possess the property of altering the refrangibility of the rays. Those rays have been called the fluorescent rays, from the circumstance that some of the varieties of Fluor Spar exhibit this phenomenon in a remarkable manner. In the engraving {fig. 4,) the curved line l from a to c 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 nD 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, wliich were employed, probably, as solvents for certain coloring principles. The term was subsequently exclusively used to designate ardent spirits, and ultimately the radica' 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 iii 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 lie 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 efftxits on the body and mind (Odyssey IX. and XXI.) ; 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 spirits,'^ 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 Yillencuve, 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. Tlie 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 undei-go when exposed, at a certain tem- perature, to contact with organic or eve* 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 i-ecognized as the vinous or alcoholic fermentation. In this process solutions containing sufiar — either the juice of the grape (see Wink) or •an infusion of germinated barley, malt, (see Bkkii) — arc mixed with a suitable quantity of a ferment ; beer or wine yeast is usually employed (see Yicast), and the whole maintained at a temperature of between TO" and 80" F. ('21° to 2G" C.) Other bodies in a state of putrefactive decomposition will effect the same result as the yca-t, swell as putrid )>lood, white of egg, &c. The licjuid swells up, a considerable quantity of froth collects on the surface, and an abundance of gas is disengaged, wliich is ordinary carbonic acid (CO"). The composition of (pure) alcohol is expressed Ijy t!ie formula C* H" 0^ and it is jiroduced in this process • 'riioiiison'.'* History of Chemistry, 1. 41. (1S30.) t .Vuuuk-s do Chimio, xlit. 225. 28 ALCOHOL. by the breaking up of an equivalent of (/rape sugar, G^* W^ 0^', into 4 equivalents of alco- hol, 8 of carbonic acid, and 4 of water — Qli 2-.« 028 C" H-^ 0° = 4 (C* H« 0') H< 0* =4 HO 8 CO' C 0' It is invariably the grape sugar which undergoes this change ; if the solution contains cane sugar, the cane sugar is iirst 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. Tlie 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, kc. — the product is denomi- nated u'ine ; from a decoction of malt, ale or bier ; from a mixture of honey and water, mead; from apples, cider ; from the leaves and small branches of the spruce-fir (abies excclxa, &c. ), together with sugar or treacle, spruce ; from rice, vice beer (which yields the spirit arrack) ; from coc-oa-nut juice, pcdm 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 300,000 gallons of spirits are annually lost ; but the cost of collecring it would far exceed its value. 2. Distillation. By the process of distillaiion, ardent spirits are obtained, which have likewise received diff"erent names according to the sources whence the fermented liquor has been derived : viz. that produced by the distillation of wine being called brandi/, 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, 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 " 19.00 London Small Beer - - " 1-28 Claret - " 15-10 Sauterne (( 14-22 Brandy - - " 53-39 Burgundy (1 14-57 Rum . - " 53-68 Hock - (( 12 08 Gin . - " 57-60 Tent - i( 13-30 Scotch Whiskey - - " 54-32 Champagne - ii 12-61 Irish Whiskey - - - " 53-90 Gooseberry - (1 11-84 Port (1834) 22-46 Port (best) Sherry (Montilla) 19-95 Marcobrunner Madeira 22-40 Champagne (1st) Claret (Haut Brion) 10-0 Champagne (2d) Chambertin 11-7 Home Ale Sherry (low quality) 20-7 Export Ale Sherry (brown) 23-1 Strong Ale Amontillado 20-5 Stout Mansanilla 14.4 Porter - The following results were obtained by the writer more recently by this process, (1854.) Percentage of Alcohol by Volume. 20-2 8-3 12-12 10-85 6-4 6-4 9-0 5-7 4-18 M. I'Abbe Brossard-Vidal, 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^ (173° 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 sho\vn 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 Dr. Urc. 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 lifjuor 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 * Brando's Manual of Chemi.stry ; also Philosophical Trans., ISll. + Comptes Ecndus, xxvii. 374. ALOOHOLOMETRY. 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 indicetes 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- in'^ point of the mixture — in fact, to the extent of from half to a whole degree, according to the amount present. Silbermannh Alethod. — M. Silbermann* has proposed another method of estimating the streno-th 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 50° C. (122° F.) ; it is evident, therefore, that the expansion c£?> 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 50° 0. (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, b b, 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 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, as 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, wiiich 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. r - 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. Bencc Jones, f * Comptes Renfliis, xxvii. 418. t On the Acidity, Sweotncss, and Strontrth of different Wines, by II. Bcnco Jones, M. D., F. R. S., Proceedings of the Koyal Institution, February, 1854 38 ALOOHOLOMETRY. By Distillation (Mr. "Witt) By Alcoholometer per cent, by measure, per cent, by measare. Port, 1834, 22-46 .. I g'.^ ( 20-'7 Sherry, Montilla, .... 19-95 . . \ 20-6 (20-6 Madeira, 22-40 . . -j :^^[^ Haut Brion claret, .... 10-0 . . | jj^J Chambertin, . . . . . ll'l . . "j is-o ( ''l-l Low-quality sherry, . . . 20-7 . . < Z^.^ Brown sherry, ..... 23-1 . . A „.„ Amontillado, .... 20'5 . . ] 21-0 Mansanilla, ..... 14-4: . . < ^..^ Port, best, 20-2 . . -j ^{'.J Marcobrunner, . . . . . 8-3 . . ■< „.g Home ale, . . . . . ^^ ' ' ] 'j-1 < 1-0 Export ale, . . . . . 6-4 . . •< g.g Strong ale, ..... 2-0 . . j ^^.g 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. Tabarle has constructed a peculiar instrument for determining these specific gravities, which he 'calls an cenometer ; 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 lias 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 litiuors arc 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 hvdrogen. Thus, alcohol being represented by the formula t:^ H'^ O", aldehyde becomes C 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 foll»wing 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 ciuantity of water, and three parts of sulphuric acid, mixed with four of water, 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 s- )pped 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 cai»es 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 O^SOO at o2\ 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 .034G. The number thus found is 1-5224, corresponding as nearly as could be desired to the experimental residt. Aldehyde is produced in a great number of processes, particularly during the dcstructivo distillation of various organic matters, and in processes of oxidation. From alcohol, alde- hyde may be ])rocured 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 afford 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 was formerly. By the term is now understood any organic sub- stance which, by assimilating two equivalents of hydrogen, yields a substance having the properties of an alcohol, or, by taking up two equivalents of oxygen, yields an acid. It is this latter property which has induced certain chemists to say that there is the same relation between an aldehyde and its acid as between inorganic acids ending in oiis and ic. Several very interesting and important substances are now 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 bo mentioned the oils of bitter almonds, cumin, cinnamon, rue, &c. An exceedingly important character of the aldehydes is their strong tendency to combine with the bisuli)hitcs 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 i)roximate 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 hi very small ([uantities, the success has been sufficient to warrant sanguine hopes of success. A sul)stitute for one of -them has been for some years known under the very incorrect name of artificial oil of bitter almonds. Sec Nituobenzole. — C. G. W. ALDER. {Aunc, Fr. ; J'Jrle, Germ. ; Alnuii 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 wood 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 wood is used for gunpowder. 40 ALEMBIC. ALEMBIC, a still {which sec). The term is, however, applied to a still of peculiar con- struction, in which the head., or capital, is a separate piece, 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- tion may be easily cleared out of the body. It is likewise capable, when skilfully managed, of distilling a much larger cjuantity of liquor in a given time than a retort of cfjual capn- city. In France the term alembic, or rather alambic. is used to designate a glass still. ALGAROTH, POWDER OF. Povdcr of Afr/arotti,— Enrfli'ih Foii-cler. This salt was discovei-ed by Algarotti, a physician of Verona. Chloride of antimony is formed by boiling black sulphide of antimony with hydrochloric acid : on pouring the solution into water, a white flocky precipitate falls, cS^^ESSr^ which is an oxichloridc 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 emeiic. ALGyE. {Varcch, Fr. ; Seerjras, or Alr/e, Germ.) A tribe of subaqueous plants, in- cluding the seaweeds {fucus) and the lavers (ulva) growing in salt water, and the fresh water confervas. We have only to deal with those seaweeds which are of any commercial value. These belong to the great division of the jointlcnii ahicf, of which 160 species are known as natives of the British Isles. In the manufacture of Kelp, (see Kelp,) all the varie- ties of thiatdivision 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 s:mie group, as do also those which the agriculturalists employ for manure. Dr. Pereira gives the Ibllowing list of esculent seaweeds : — lihodomcnia pahnata (or Dulse). lihodoinoiia cilia/a. Laminaria saccharina. Jr/deea cduU.l. A/aria eseidenta. Ulva latissima. nhodomevia palnutta passes imder a variety of names, dulse, dylish, or dellish, and amongst the Highlanders it is called dullinrj, 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 washed in fresh water and dried in the air. W'hen thus treated it becomes covered with a white powdery substance, which is sweet and palatable ; this is viannite, (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 : ))oilcd 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." — Stenhouse. Laminaria saccharina yields 12'15 per cent, of mannite, while the lihodomcnia pal- viata contains not more than 2 or 3 per cent. Iridaa ednlis. — The fronds of this weed are of a dull piu'ple 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 oysters. Alarin cscn/enta. — 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 tlic 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 lati!SWrt." 28. Instead, however, of keeping two kinds of " test sulphuric acid," of different satu- r.iting 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 potasli or soda, or of their respective carbonates ; and this, in fact, is the alkalimeter most in use in the factory. It should be in sliape similar to that of Gay-Lussac's, (see ///. 12,) or that described in figs. 13 and 14 ; but, like that represented by fig. 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 loO equal parts, and every division is numbered from above downwards (see A> l'^)- 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 yj 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-G2 parts, make another line, and write potash; still lower, at 54"43 parts, a third line marked carb. 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- ered by the thumb of the left hand, and if not ; or, if there be reason to think cai it not ultimately secure, then it should be heated and contracted until suffi- ciently small." 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 sulphuric acid, of specific gravity 1-1268, 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 w'atcr, 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 convenient process for the analyst, 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 hi 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 uso a graduated tube of a small bore, terminated by a small length of vulcanized india-ruhher 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 r032, and is prepared as follows : — Take 53 grains (one equivalent) of pure anhydrous neutral carbonate of soda, obtained ^85 ^90 48 ALKALIMETRY. 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 tlie whole well. The mixture having become quite cold, fill the alkalimeter witli the cold diluted acid up to the point marked 0", taking the under line of the liquid as the true level, and, whilst stir- ring briskly the aqueous solution of the 53 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 50 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 50 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 A cidy 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 sucli 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 tlie test sulphuric acid taken tiave a specific gravity of r032, we know, as we have just shown, that r032 grains' weight of that acid contains exactly one equivalent of pure sul- 18 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 — GO-70 — 33-29 grains' weight 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 sepanite 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-gFains' measure, then as much water 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, onc-lonth 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 ia 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 fto-ain into "the 10,000 grains' measure until its level reaches exactly the scratch, a. Tlie 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 rio-orously measured in the pipette should then be transferred to the glass l)eaker,°in whicli the neutralization is to take place, by removing the finger alto- <'ether, 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 imparled 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 lest sulphuric, for potash (§§ 17-22), 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 tlic 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 roaches that point, at a much greater degree of precision. lie 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- limetrical 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 yy^ 50 ALKALIMETRY. 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 j-^ 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 tli S. Potashe ej in th iobtain- e Labo- ■-5 c >.'Z i t 1 * " 1 a 1 EO 1851. 1835. cining. p. g s. •a *C » §■1 s. .1 II :1l£- i |i5 Si ° Sulpbate of poUiih Chloride of potassium - Carbonate of putash Carbonate of soda (dry) Insoluble residue - Moisture - . - - Phosphoric acid, lime, silica, &c. Alkalimetric degrees 13-47 0-95 74-10 3-01 0-65 7 -28 0-54 14-11 15-32 2-09 S-15 69-61 CS-07* 8-09 5-85 1-21 3-35 8-S2 unde- 1 ter- mined 107, ditto 14.3S 3S-S4 3-64 9-16 71 -3S; 8S-C3 2-3l! 4-17 0-44' 2.66 4-56 5.34 » 3-29< 1-20 4-27 18.17 51-83 24-17 1-56 2-98 19-69 53-90 23-17 0-20 16-19 i 33-89 26-64 19-60 3-6S 1-50 1-60 89-95 5-12 0-50 1-33 0-70 1-70 95-24 2-12 0-24 100-00 100-00 100-00 100-00 100-00 100.00 10000 100 00 100-00 56 53 1 1 55 54-4 ^ 31-6 CO 1 59-7 36.5 6S-5 69-5 75. Tlie alkalimctrical assai/ 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, ^\ part of the aqueous solution of the soda ash above mentioned (§ 75) — is transferred to the glass beaker or ves.^el in which the Saturation is intended to take place, it is tinged distinctly blue WMth 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 satuniting point is ajiproaching. 77. Having put into a glass l)caker the 1,000 grains' measure of the aqueous solution of soda ash to be examined, (§ 75,) and of the lr 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 5 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 j 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 -frVg quite destroys the ductility of gold. Gold and platinum alloy forms a somewhat clastic metal. Ilermstadt's imitation of gold consists of Ifi parts of platinum, 7 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 uncombincd mercury. This alloy, when put into the hollow of a decayed tooth, veny soon becomes exceedingly hard. Some dentists add a little copper, or gold, or platinum leaf, under the impression that the amalgam becomes harder. Copper Alloys. — Copper alloyed with zinc forms Brass, and with tin, we have Bronze. (See those articles.) The alloys of the ancients were usually cither brasses or bronzes. The following analyses of ancient coins, (Sec, 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. n., when Albertus Magnus speaks of zinc as a soni-ntctal, and calls the alloy of copper and zinc f/olden inarcn- si!r : 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, althougli it was not thought to be an ore of zinc or of any other metal. — See Watsoii's Chemical A'ssays. ALLOY. 61 Date. ^ .J -• 1 .S >3 § .s N in a. is 1 D.C. A.D. Mi . - . - 5U0 69-69 7-16 21-82 •47 trace trace ■57 StJiuis - - • - 5(J0 62.04 7-66 29.32 •18 — trace ■19 ■23 Quadrans . . - Hiero I. - ■ " 500 72 22 7-17 19-56 •40 — trace •20 •23 470 9415 5-49 — •32 Alexander the Great - 335 86-77 12-99 — — — •06 Philippus III. Philippus V. - - Copper coin of Athens Egyptian, Ptolemy IX. 323 90 27 9-43 200 8515 11-12 2-85 •42 — trace ? 88-34 9-95 •63 •26 — — trace trace 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 63-69 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 Bra^^s of the Cas- ) sia Family - | 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 — — — — — •23 Celt .... 90-68 7-43 1-28 trace — — trace Celt . - - - 90-18 9-81 — trace Celt ... - 89-33 9-19 — ■33 — — ■24 Celt - - - - 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 7914 4 97 9-18 •23 6-27 Greek Imperial Samosata 212 70.91 6-75 21-96 trace Victorinus, 8e3. (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) Claudius Gothicu3(No. 2) — |-263 81-60 84-70 7-41 3-01 811 2 67 •31 trace 1-86 7-93 Tacitus (No. 1) - ■275 86-08 3-63 4-87 — — 4-42 Tacitus (No. 2) - — 91-46 — — 2^31 — 592 Probus (No. 1) - — •275 90-63 2 00 2. S3 •61 1-39 2-24 Probus (No. 2) - 94-65 •45 ■45 •80 — 3-22 ^^ 1 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 Allots. — 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 dri/ 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 u.sed, as it separates on cooling. Antimony twenty parts and lead eighty parts form the printing-type of France ; and li'ad and antimony are imitcd in various proportions to form the type-metal of our printers. _ See Type. Mr. James Na.smyth, in a letter to the " Athenjcum," (No. IIYG, p. 511.) directed atton- tiou to the employment of lead, and its fitness as a substitute for all works of art hitherto executed in bronze or marble. lie 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; al)out 3 per cent, is the usual f|uaiitity. The alloy is rolled out into sheets. — Holtzapffel. We are not aware tliMt this alloy has ever been employed. 62 ALLOY. Emery wheels and grinding tools for the lapidary are formed of an alloy of antimony and lead. Ort^an 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 bo 40 lbs. of metallic arsenic to one ton of lead. Tabular Stateincnt of the Physical Peculiarities of the Principal Alloys, adopted, with some alterations, from the ^^ Encyclopedic Technologique.^' BRITTLE METALS. Aksenic. With Zinc, rendering it . brittle. 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. With Gold, a gray metal, very brittle. 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. With Silver. 23 of silver and 14 of arsenic form a grayish-white brittle metal. With Lead. Arsenic ren- ders lead brittle. The combination is very inti- mate; not decomposed by heat. With Tin. Brittle, gray, lamcUated ; lees fusible than tin. With Mercury. interest. Without Antimony. This alloy is very brittle. 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. Forms readily a pale-yellow alloy, breaking with a fracture like porcelain. Alloys readily : the alloys are brittle. Those form- ed with equal parts of the two metals are of a fine violet color. These have a strong affini- ty ; their alloys are al- ways brittle. 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 antimony and tin are very wliite. They become brittle when the arsenic is in large quan- tity. A gritty white alloy. Bismuth. Unknown. Doubtful. Similar to antimony, of a yellow-green color. Pale-red brittle metal. Alloys brittle lated. and lamel- 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. Tin and bismuth unite in all proportions by fusion. All the alloys are more fusible than tin. Mercury dissolves -a large quantity of bismuth with- out losing its fluidity; but drops of the alloy elongate, and form a tail. 1 ALLOY. 63 DUCTILE METALS. Iron. Gold. Copper. Silver. With Zinc. See A greenish-yellow See Brass. Silver and zinc com- Galvanized Iron. alloy, which will take a fine polish. bine easily, form- ing a somewhat brittle allov. With Iron or Steel. Gold and iron alloy Iron and copper do When 1 of silver with ease, and not form true al- and 500 of steel form yellowish al- loys. When fused are fused, a verv loys, A'arving in together, the iron, perfect button is color with the however, retains formed. — Stodart proportions of the a httle copper. — and Faraday. metals. Three or Several methods four parts of iron for coating iron united with one of with copper and gold is verv hard. brass will be de- and is used in scribed. the manufacture of cutting instru- ments. With Gold - 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 m the metal employed in the manufacture of jewellery. Gold and silver mix easily together ; iSut they do not appear to form a true combination. Jewellers often employ Vor vert, which is compose (1 of 70 parts of gold and 30 of silver, which corresponds very nearly to the alloy possessing the maximum hardness. With Copper Silver and copper alloy in all pro- portions. Tliese al- loys are much used in the arts. The maximum hard- ness appears to be produced when the alloy contains a fifth of copper. With Lead, does A very brittle alloy. Do not appear to Unite in all propor- not appear to A thousandth pt. form a true alloy. tions ; but a very form any alloy. oflead is sufficient to alter the due- tiUty of gold. small quantity of lead will greatly diminish the duc- tility of silver. With Tin. A very The alloys of gold Of great importance. Alloys readily. A little iron dimin- and tin are brit- See Bronze. very small quan- ishes the mallea- tle ; they preserve. tity of tin destroys bility of tin, and however, some the ductility ot gives it hardness. ductility when the proportion of tin does not exceed J^. silver. With Mercury. Mercury has a most An amalgam which The amalgamation of Mercury has no powerful action on is formed with dif- these two met.als action on iron. gold. See Amal- ficulty, and with- is a little less ener- gam. out interest. getic than between mercury and gold. See Amalgama- tion. U ALLOY. In addition to these, the alloys of iron appear of sufficient importance to require some further notit e. 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 inditferent to the magnet. Iron and Silver ; Steel and Silver. — Various experiments have been made upon alloys of iron and steel with other pietals. The only alloys to which sufficient importance has been given are those of iron and silver and steel and silver. M. Guytou 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 separa/cs for the (jreatest 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 jjroperties, 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 It 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 probal)ly receive important applications. Mr. Oxland and Mr. Truran have given, in " Metals and their Alloys," the following use- ful taVjular 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 1 " springs 97-000 - - 3-000 ' Bronze for statues 91-400 5-530 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 sbeet - 84-700 15-300 Gilding metal - - - 73-730 27.270 Pinchbeck 80-200 20-000 Prince's metal . . - 75-000 25-000 " "... 50-000 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 50-000 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 phnenla) is cultivated in Jamaica iu what are called Pimento walks. It is im- ported in bags, almost entirely from Jamaica. ALMOND. (Aiiiande, Fr. ; 3Iandclus, Germ. ; Amygdal communis.) De Candolle admits five varieties of this species. A. amara, bitter almond ; A. dulcis, sweet almond ; A. frariilis, tender-shelled almond ; A. macrocarpa, large-fruited almond ; A. peisicoides, 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. Barbary and Italian almonds resemble the latter, but arc generally smaller and loss flattened. — Brande, Dictionary of Pharmacy. ALMOND OIL. A bland fixed oil, obtained by expression from cither bitter or sweet almonds ; usually from the former, on account of their cheapness as well as the gi-eater value of the residual cake. The average produce is from 48 to 52 lbs. from 1 cwt. of almonds. — Pereira. ALMOND POWDER {farina amygdalce) is the ground almond cake, and is employed as a cake for washing the hands, and as a lute. ALOE. {Aloes, Fr. ; Glauindes aloe, Germ.) In botany a genus of the class Jlexan- dria monoffynia. 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-strings, 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 iiolding 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 discn- 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 clay 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 arc introduced into the bath, which 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 req-uired 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 am'mal of Peru, of the Llama species ; also the name given to a woollen fabric woven from the wool of this animal. ALUM. {Ahm, 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' 8S0' 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' 3S0' NH< OSO' -f 24HO. The same thing occurs with soda ; soda alum is APO' SSO' 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^ 3S0^ KOSO= -\- 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 Al \ /c i i *. e . i lo o.-> i „t„~ nh ., . T,^„, << 1 u rn / I Sulphate of potash - 1S*32 or 1 atom 27 Alumina - 10"94 1 52 ( j o i i * r i ■ o/. .n u ■> u -nrr. or -^ Su phate of alumma 36-21 " 1 l72 ( Sulphat •] Sulphat ( Water Sulphuric acid 33-68 " 4 " 160 f "' ] ^^^'-^^^"^ ^'r'"'^"^^^ . { .. 216 Water- -45-49 "24 " 216) I ^^^ter 40 -ib i ^io Its specific gravity is 1-724. 100 parts of water dissolve, at 32 degrees Fahrenheit, 3-29 alum. " " " 50 " " 9-52 " " " " 86 " " 2201 " n u (( J22 " " 30-92 " U i< « jgg « 1. (jQ.QY U " " " 212 " " 857-48 " 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 " «i 77 »i « 4.5 u " 100 " " 2-2 " " 122 '•' " 2*0 " " 145 " " 0-4 " " 167 " " 0-1 " " 189-5 " " 0-06 " ALUM. 67 A solution saturated at 46° is 1-045 specific gravity. This diiference in the rate of solu- bility in hot and cold water renders it easily separated from many other salts. The crystals are permanent in the air, or nearly so, unless the air be very dry ; if kept at 180° they lose 18 atoms of water, but alum deprived of its water and exposed to the air of summer took up 18 atoms in 47 days. It melts at a low temperature in its water of crystallization. At 356' it loses 43*5 per cent, of water, or 23 atoms; the last atom is only lost when ap- proaching red heat. At a red heat the sulphate of alumina loses its acid, and the alumina seems then able to remove some acid from the potash, losing it again by heat. Alum, when heated with common salt, acts like sulphuric acid, and gives oft" muriatic acid ; the same with chlorides of potassium and ammonium. If boiled with a saturated solution of chloride of potassium, hydrochloric acid is formed and a subsulphate of alumina falls down ; this occurs only to a small extent with chloride of sodium, and still less with sal-ammoniac. Appli'calions of Alum. — Alum is an a^ringent. Its immediate effect on man is to corrugate the fibres and contract the small vessels. It precipitates albuminous liquids and combines with gelatine. It causes dryness of the mouth and throat, and checks the secre- tions of the alimenary canal, producing constipation ; in large quantities, nausea, vomiting, puro-ing. It is given in lead coUc, to convert the lead into sulphate of lead, and used externally. Its principal use is in dyeing ; calico-printers print it as a mordant, the cloth is then put "into the dye, and the printed parts absorb the color. Paper-makers use it in their size and bookbinders in their paste. It is used in tanning leather, and sometimes, both in Asia and Europe, it is used for precipitating rapidly the impurities of water. This is a dangerous process, unless there be a great amount of alkaline salts, such as carbonate of lime or soda to neutralize the acid. It is extensively used in correcting the baking qualities of bad flour, for which the experience of many has decided that it is a valuable remedy ; unfortunately, it is also used to make excellent flour whiter, when there is no need of its presence. Liebig says that lime is equally good, and of course much safer. From time immemorial it has been used to prevent the combustibility of wood and cloth. Alum heated with charcoal or carbonaceous substances forms Homberg's phosphorus, which inflames spontaneously. It is composed of alumina, sulphide of potassium, and charcoal. Burnt Alum., or dried alum, is made by gently heating alum till the water is driven off. The alum first melts in its water of crystallization and is then dried. It has a stronger action than the hydrated crystals, and is a mild escharotie. It reabsorbs water. Ammonia-alum readily loses all its ammonia when heated, and the sulphuric acid may be driven off the remaining sulphate of alumina, so that the pure earth-alumina will remain. Neutral Alum is a name sometimes given erroneously to alum which has had some of its acid neutralized by an alkali. It is, in fact, a basic salt of alumina, which may also be made by dissolving alumina in ordinary alum. It deposits a basic salt more readily than ordinary alum, and may be of service in some cases of printing. Properly speaking, the common alum is the neutral salt. Testing of Alum. — Alum being generally in large crystals, any impurity is more readily seen ; this is said to be the reason for keeping up the practice of making this substance instead of the sulphate of alumina alone, which is less bulky and fitted for nearly every purpose for whj).-h altnn is used. But probably the ancient accidental discovery of the pot- ash form has determined its use to the present day. Iron is readily found in it, by adding to a dilute solution ferrocyanide of potassium or prussiate of potash, which throws down Prussian blue. A very delicate test is sulphuret of ammonium, which throws down both the alumma and iron, but the blacking of the precipitate depends on the amount of iron. The total amount of iron is got by adding pure caustic pot;ish or soda till the solution is strongly alkaline, washing and filtering off the oxide. To look for lime, precipitate the alumina and iron by ammonia, boil and filter, the lime and magnesia are in the solution, add oxalate of ammonia -, add tartaric acid to keep up the iron and alumina, make alkaline by ammonia, then precipitate the lime by oxalate of ammonia, filter, and precipitate the magnesia by a phosphate. Silica and insoluble basic sulphates arc obtained by simply dis- solving the alum in water and filtering. If silica, it is insoluble in acids ; if a basic sulphate, it will dissolve in sulphuric acid, and the addition of sulphate of potash or ammonia will convert it into potash or ammonia-alum. Its formula, according Jo Graham, is a basic alum, HO SO' + 3(A1'0'S0') -f OHO. By losing alumina it becomes the neutral salt. . Sulphate of Alumina. — The first step towards the production of alum is the sulphate of alumina. This is found in various proportions in alum stone. The pure mineral has the following composition : — 1 atom of alumina - - 15*42 per cent, 3 atoms of sulphuric acid - 85'99 " 18 atoms of water - - 48-59 " 100- 68 ALUM. There are many analyses of natural specimens closely approaching this. It is found crys- tallized in a close mass of fine, white, flexible needles, of a feather or hair form, and has been, like a few other substances, called hair-salt. It is also found with various degrees of impurity, sometimes with a smaller amount of water. Knapp has collected the following list of analyses : — Analyses of Natural Sulphate of Alumina or Feather Alum. The manufacture of alum involves the making of sulphate of alumina in the first instance in all cases where potash is not present in the ore ; for this reason the description of both is included in one article. Ores or Raw Material. — The chief difficulty in manufacturing alum has been the solu- tion of the alumina. This substance is generally combined with silica in such a strong cooj- binution, that even powerful acids cannot remove it without assistance. The older methods, however, took no notice of these difficulties, and obtained the alum more or less directly from nature. The method now practised at the Solfatara di Pozzuoli and the island Vul- cano is simply to take the efflorescence and the earth containing it, wash it with water, and concentrate. But it very seldom contains a sufBcient amount of potash to form alum. A salt of potash is then added, chiefly a carbonate. To transform this into a sulphate, a por- tion of the sulphate of alumina is decomposed. The use of a carbonate is a wasteful method of modern times ; the ancients would have felt no difficulty, but boiled all down, and so obtained the whole alumina there. Their product, therefore, would have been basic sul- phate of alumina, which it evidently was when this practice was resorted to. When they merely concentrated and then crystallized, they got pure alum ; but they lost a great deal of their alumina. At Tolfa the alum is obtained from a compact crystalline substance called alunite. The analysis of Cordier makes it a combination of alum with alumina. If treated with water only, it will not give out alum ; but if moderately calcined, it breaks up, gives out a large amount of alum, and the liquid is then boiled down for crystallization. Here are specimens of the ore, two of which contain a considerable amount of potash. As there is seldom enough of potash found, it must be added in the form of sulphate of potash or chloride of potassium. Sulphuric acid 36-187 34-6 20-06 Alumina 35-105 40-0 S9-70 Potash 10-824 15-8 Lime 0-SO Water 18-124 10-6 59-94 100-240 100-0 120-00 These formations of alum are generally found where sulphurous gases are exhaled rock is gradually decomposed. the ALUM. 69 It is not, however, found so rich in the great majority of cases. yses of some alum stones : — The following are anal- Klaproth. Klaproth. Descotil. Cordier. Tolfa Alum Stone. Beregszaz Alam Stone. Montlone. Mont d'Or. Silica Alumina Sulphuric acid - . - - Potash Water ..... Oxide of iron 56-5 19-0 16-5 4-0 3-0 62-3 17-5 12-5 1-0 5-0 40.0 35-6 13-8 10-0 28-4 31-8 27-0 5-8 3-7 1-4 When there is no silica, but only sulphuric acid, alumina, and potash, we have a natural alum, and in that case there is nothing to be done towards the manufacture. But it rarely happens that the constituents exist in a proportion to form the crystalline salt. There may be sulphate of alumina, hydrate of alumina, and some true alum, or sulphate of alumina and potash. This excess of hydrate of alumina forms, when united with the sulphate, a basic or insoluble sulphate of alumina, and nothing but the sulphate of pota.sh becomes soluble. When the hydrate is heated, the water escapes ; the sulphate of alumina and potash are then capable of being washed out together, and alum is obtained. At Tolfa it is obtained in crystals, covered over with a light red powder of peroxide of iron. This reddish covering always accompanies the Roman or partly cubical alum, and it has been sometimes added in order to give common alum the appearance of the Roman. As the principal difficulty in the manufacture of alum is the solution of the alumina, it is unfortunate that so much of the hydrate is destroyed, as in the process mentioned, when sulphuric acid would readily dissolve it and greatly increase the produce. By the method described to us, the measure of alum is simply the amount of the potash. All that cannot find potash to unite with is lost. Occasionally ammonia-alum is found in nature. Analyses have been made of specimens from Tschermig, in Bohemia, by Stromeyer : — Alumina . 11-602 Ammonia - 3-721 Magnesia . 0-115 Sulphuric acid . 36-065 Water - - 48-390 99-893 Sulphate of alumina Sulphate of ammonia Sulphate of magnesia Water 38-688 12-478 0-337 48-390 99-893 Soda-alum is also found naturally. Alum from Peru, by T. Thomson. Sulphate of soda 6-50 Alumina 2255 Sulphuric acid 32-95 Water 39-20 101-20 From the Andes. Sulphuric acid 86-199 Alumina - - . . 11 -511 Soda 7-259 Water 43-819 Silica 0-180 Lime 0-255 Peroxide of iron 0*199 Protoxide of iron - - - 0-760 100-162 Messrs. Richardson and Ronalds have given some very minute analyses of the Whitby and Campsie shales. 70 ALUM. "Whitby. Top Rock. Bottom Eock. Top Eock. Campsie. Top Eock. Bottom Eock. Sulphur Iron - Sulphuret of iron Silica - Protoxide of iron Alumina Lime - Magnesia Oxide of manganese Sulphuric acid Potash Soda - - - Chlorine Carbon and loss - Carbon Coal - Loss - - - Water 4-20 52-25 8-49 18-75 1-25 0-91 traces 1-37 0-13 0-20 traces 8-50 51-16 6-11 18-30 2-15 0-90 traces 2-50 traces traces traces 4-97 2-88 8-29 2-00 95.40 91-91 22-36 18-16 15-40 11-35 1-40 0-50 0-15 0-90 23-44) 15-04/ 15-40 11-64 2-22 0-32 9-63 0-47 2-18 18-91 0-40 2-17 0-55 0-05 1-26 0-21 29-78 28-80 3-13 8-51 0-59 8-54 100-00 99-99 100-00 As the Top one contains a larger excess of iron pyrites than the Bottom, they are mixed so as to diffuse the sulphuric acid equally. Erdmann has thus analyzed his German specimens : — Garnsdorff. Wezelstein. ^Sulphuret of iron . - . . 7-533 10-166 Silica 0-060 0-100 Soluble in acid. - Peroxide of iron Alumina ...... 0-966 1-833 2-466 3-166 Lime 0-400 1-000 Magnesia trace 1-022 Silica .---.-- 50-066 52-200 Alumina 8-900 17-900 Insoluble in acid. -! Peroxide of iron Magnesia .-.--. 1-300 1-000 3-566 1-133 Lime trace trace Coal 22-833 0-805 Water 2-208 5-080 Other shales will be found of interest ; the following are by G. Kersten : — « Hermann- schachto. Gluckauf- gung. Elucher- scbachte. Curbonaoeous matter Silica Peroxide of iron Alumina Magnesia Sulphur Oxide of manganese ........ Sulphate of lime ..-.•- 41-10 44-02 6-23 5-60 0-32 1-25 0-12 traces 27-92 51 32 8-40 7-62 0-26 2-89 traces traces 34-20 50-21 0-42 5-21 0-53 1-72 traces traces 98-64 98-41 98-39 ALUM. n Shales from Freienwalde, Shales from Puzberg^ by Klaproth. by Bergeraann. Alumina - ' - - 16-000 10-80 Silica - - - 40-00 45-30 Magnesia . - - 0-25 Sulphur - - - 2-85 3-94 Carbon - - - 19-65 5-95 Protoxide of iron - 6-40 5*50 Oxide of manganese - 0-60 Sulphateof protoxide of iron 1-80 - - - - - 5-'73 " " alumina 1-20 » ". lime 1-50 l-H " " potash 1-60 ----- 1-75 Chloride of potassium 0-50 0-35 Sulphuric acid - - 0'4'7 Water - - - 10-75 16-50 101-20 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, - l-'rO Silica, .- 10-32 Alumina, ----------- 9-21 Magnesia, traces Oxide of iron, 2-30 Oxide of manganese, -- 0'31 Sulphur, T-IS Water, 33-90 Carbon, 31-03 100-00 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 WhitVjy 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, FeS--f-70=reO SO=-f-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 sulphupc acid and protoxidoof iron. Tills 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 elfcct these changes it is desirable to burn very slowly, so as to allow no loss of sulphurous acid, and, in -wiusliing, 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 ))eing 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. Y2 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- mission. 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 Tcroxide of iron, 20-60 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 chloride 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 reerystallization, 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 op 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 witli tlie 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. A'um 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 chiy, 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, burthis 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. (Al'-O^, 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' ; AFO', 8S0'-|- 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 hvdrate, the anhydrous alumina is produced ; but it may be obtained more readily by heating ammonia-alum, (NIPO, SO' ; APO' 3S0' + 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 ; M-hilst, 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 cariies 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 " lakes." 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." Otlier bodies have a similai* attraction for coloring matters, e. (/. 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 tlie solution in a soluble allotro[)ic 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 insolublo 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. ALUMIXA, ACETATE OF. The acetates of alumina arc extensively used in the arts on accoimt of tlie 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- * Chcmic.ll Society's Quarterly Journal, vi. 216. 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 Cruni,* the solution resulting from the decomposition of sul- phate of alumina (APO\ 3S0^) by monobasic acetate of lead contains the salt APO', 2C''H^0', (biacetate of alumina,) together with one equivalent of free acetic acid, the com- pound Al-0^, 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.,) Crura obtained a fixed residue completely soluble in water, the composition of which, in the dry state, approached AFO', 2C'IPO=-[-4riO.— 11. M. W. ALUMINA, SILICATES OF. Silicate of alumina is the chief constituent of conmion 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, Al-0\ 8SO=-(-18IIO, which is obtained by dissolving alumina in sulphuric acid, crystallizes in needles and plates ; but sulphuric acid and alumina combine in other proportions, c. g. a salt of the formula AFO', 3S0^-j-Al*0^ was 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', 3S0^ 4~ 2AP0^ -f- 9II0. 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. {Sym. Al., cquiv. 13'Y.) 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. Deville 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 t\ibes 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 with 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, A1"CP,) in which 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 topjether 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 nuich 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. Durin"- 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 Aluminmm by Electrolysis. — Mr. Gore ha3 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, AFF' ;) but since this process is far more troublesome and expensive than its reduction by sodium, it has been altogether superseded. Preparation of Aluminium from K-ryolite. — 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, Al'-F^ 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, (XaCl, AFCl',) 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. Mac. vii. 20T. + Phil. Mag. x. 304. J Pocgrendorf, Annalcn, and Phil. Mag. s. 233. § Ann. de China, et Phys. xlvi. 415. || Chemical Gazette, 1856, Sfe. 76 ALUMINIUM. Specific gravity, 2-56, and, when hammered, 2-6'7. Conducts electricity eight times better than iron, and is feebly magnetic. Its I'using point is between the melting points of zinc and silver. By ik'ctrolysis it is obtained in forms which Deville believes to be regular octahedra ; but Rosf, 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 unaffected 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 Dc- 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 f 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, 2-87 per cent, of silicon, 2-40 of iron, 6-38 of copper, and traces of lead. The following analj-sis of commercial aluminium was communicated to the British Asso- ciation, at its meeting in 1857, by Professor Mallet : — Made in Paris. Made in Berlin. Al 92-9C9 96-253 Fe 4-882 3-293 Si 2-149 0-454 Ti - - - - - - trace ..... trace 100-00 100-00 AUoysi of Aluminimn. — Very small quantities of other metals suffice to destroy the malleability and ductility of aluminium. An alloy containing only J^ 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 -j-Jo P''"'^ ^^ 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 bril- liance and color of pure silver, over w/iicli the allot/ 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 y'^ of its weight • ofiiluminium has the color and brilliance of gold, and is still very malleable, (Tissier ;) and when the aluminium amounts only to Vg, {i. c. 20 per cent.,) the alloy is quite white, (Bchrat/.) An alloy of 90 parts of copper and 10 of aluminium is harder than common bronze, and is capable of being worked at high temperatures easier than the best varieties of iron. Larger fiuantities 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. Ma?. X. 14-3. t Journal pr. Chcm. Ixvii. 40S. t .Toiirnal pr. Cliem. Ixvii. 494 § C. and J. Tissier, Comptes Eondus, sliii. 6S5. J ("DUiptcs IJendus, 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 nol oxidizing by exposure to moist air. Uses of Aluminium. — No very important apphcation of aluminium has yet been made, althou<^h 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 sec.) 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, (Al-CP— 133-9.) Preparatio7i.— Chloride 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 ffirsted, 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 oxj'gcn from the alumina as it would from lime. But if the attraction of the chlorine for the metal be supported by the affinity 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 p;issed 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 iq water, but cannot l)c recovered by evaporating tlie solution. — II. 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- * Proceedlnss of tho Royal Institution, March 14. 18r)G. , t Pliil. Majr. x. 245. I Tlio present price of Aliiniiniuin in Lon(l(m is Hn. \>CT ounce, whilst only in M.'vrch, 1S50, just after M. Dovillii's experiments li.id been made, it cost 3^. per ounce. § It is calculated that more than a million sterliiii; is annually expended i!i the inetropolis on tho paint necessary to protect tho iron-work from decay. — lier. J. lAtrlow. 78 ALUM SHALE. 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 Ilurlet and Campsie, near Glasgow. A full description of the alum shale, and of the processes 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 Amalgam 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 : — Silver. Mercury. Moschellandsberg, - - - 36-0 ... 64-0 by Klaproft. Ditto, - - - 25-0 - - - 'ZS.S " 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 Biance, 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 tiie platinum region of Columbia -, and it has been reported from California, especially from near Mariposa. Schneider give its composition, mercury, 5*7 "40; gold, 38-89 ; 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 togcttier, 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, for 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 tip in a mortar, a plastic mouldable mass, like poor clay, is obtained, the consistence of which 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. Pcttenkofer 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 GO" to 70', with finely divided rcguline 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 bo 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 bv several chemists. Dobereiner states that when 816 grains of amalgam of lead (404 mercury and 412 lead) were mixed, at a temperature of 68", with 688 grains of the amalgam of bismuth, {H)i mercury and' 284 bismuth,) the temperature suddenly fell to 30^, and by the addition of 808 "•rains of mercury (also at 68") it became as low as 17' ; the total depression amounting 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 ay/iber spirit var- nixfies ; 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 cast 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, q33jj3:q 'J'p^g 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 off 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 tJ 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 a^UOua- Tos, 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. {Amtthijste orientale, Fr. ; Bcmanthspath, Germ.) Tiiis term is applied to those varieties of corundum which are of a violet color. See Cokcndum, — 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 wliich they are composed. A variety of amianthus (the amianthoide of Ilaiiy) is found at Oisans, in France, the fibres of which are in some degree elastic. The word amianthus (from afilavros, undefiled) is expressive of the easy manner by which, when soiled, it may bo cleansed and restored to its original purity, by being heated to redness in a fire. See ASBESTIS. — H. W. B. AMMONIA. NIP, eqv. 17. {Atnniomaque, Fr. ; Ammoniak, Germ.) The name given to the alkaline gas which is the volatile alkali of the early chemists. The real origin (Tf 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 &ixfios, sand, as it was found in sandy ground. It is probable that Pliny was acquainted with the pungent smell of ammonia. Dr. Black, in 1750, 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. 80 AMMONIA. 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 I^e- big's view, but it is opposed by Mulder and Yille. From the air, ammonia 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. — Vogcl. Ammonia is present in the exhalations from volcanoes. During the eruption of Vesu- vius in 1*794, 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, according 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 Devil) c. 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 nmch 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 effected. 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- bit ;) so again, if hydrogen and l^inoxide 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 Jullicn, in their patent of January 18, 1848, describe 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 liberated in the manufticture 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 JuUien 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 600° 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 uncondenscd 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 Cheinical 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 * Annales de Chimio et dc Physique, xliii. 1-19. t Phann. 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 liciuid. It is combustible, but less so than hydrogen, on account of the iucombustible nitrogen wliich it contains ; but 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 Anunonia-'tnetrc. 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 iu 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 instance, one gallon of liquid ammonia, specific gravity 880, weighs 8 lbs. 128 oz. avirdupois; its percentage of ammonia, by weight, is 33"117 ; it contains 96 test-atoms of ammonia in one gallon, and 20400.0 grains of ammo- nia in one gallon; and, lastly, 104r"16 septems containing one test-atom of ammonia. Although no hydrometer, however accurately constructed, is at all equal to the Centigrade mode of chemical testing, yet the Ammonia-meter, and the Table accompanying 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 tlie 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. •s'zsoo 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 20400-0 104^1 6 ■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 3M72 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 •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 SO 17000-0 125-00 •90125 9 0^2 26-610 79 16787-5 126-58 Vol. III.— 6 1 — — 1 1 82 AMMONIA. Table of Liquid Ammonia, (continued.) Specific Gravity of the Liquid AnimoDia. 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 16.575-0 128-21 90375 9 0-6 25-865 77 16362-5 129-87 90500 9 0.8 25-493 76 16150-0 131-58 90C25 9 1-0 25-123 75 15937-5 133-33 90750 9 1-2 24-754 74 15725-0 135-13 90875 9 1-4 24-386 73 15512-5 136-98 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 91375 9 2-2 22-924 69 14662-5 144-93 91500 9 2-4 22-561 68 14450-0 147-06 91C25 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 13812-5 153-85 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 92625 9 4-2 . 19-337 59 12537-5 169-49 92750 9 4-4 18-983 58 12325-0 172-41 92875 9 4-6 18-631 57 12112-5 175-44 93000 9 4-8 18-280 56 11900-0 178-57 93125 9 5-0 17-929 55 11687-5 181-82 93250 9 5-2 17-579 54 11475-0 185-18 93375 9 5-4 17-231 53 11262-5 188-68 93500 9 5-6 16-883 52 11050-0 192-31 93625 9 5-8 16-536 51 10837.5 196-08 93750 9 6-0 16-190 50 10625-0 200-00 93875 9 6-2 15-846 49 10412-5 204-08 94000 9 6-4 15-502 48 10200-0 208-33 94125 9 6-6 15-158 47 9987-5 212-77 94250 9 G-8 14-816 46 9775-0 217-39 94375 9 7-0 14-475 45 9562-5 222-22 94500 9 7-2 14-135 44 9350-0 227-27 94625 9 7-4 13-795 43 9137-5 232-56 94750 9 7-6 13-456 42 8925-0 238-09 94875 9 7-8 13119 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 8075-0 263-16 95375 9 8-6 11-777 37 7862-5 270-27 955O0 9 8-8 11-444 86 7650-0 277-78 95625 9 9-0 11-111 35 7437-5 285-71 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 68000 312-50 96125 9 9-8 9-7901 31 6587-5 322-58 96250 9 10-0 9-4620 30 6375-0 333.33 96375 9 10-2 a- 1347 29 6102-5 344-83 96500 9 10-4 8-8083 28 5950-0 357-14 96625 9 10-6 8-4827 27 5737-5 370-37 96750 9 10-8 8-1580 26 5525-0 384-62 96875 9 11-0 7-8341 25 5312-5 400-00 97000 9 11-2 7-5111 24 5100-0 416-67 97125 9 11-4 7-1888 23 4887-5 434-78 97250 9 lie 6-8674 22 4675-0 454-54 97375 9 11-8 6-5469 21 4462-5 476-19 97500 9 12-0 6-2271 20 4260-0 500-00 •97625 9 12-2 5-9082 19 1 4037-5 526-32 AMMONIA. 83 Table of Liquid Ammonia, (continued. Specific Gravity of tiie Liquid Ammoniji. Weight of an Imperial Gallon in Avoirdupois lbs. and ozs. Percentage of Ammonia by Weight. Test-atoms of Ammonia in one Gallon. Gr.ains of Ammonia in one Gallon. Septems containing one Test-atom of Ammonia. •97750 lb. oz. 9 12-4 5-5901 18 3825-0 555-56 •97875 9 12-6 5-2728 17 3612-5 688-24 •98000 9 ]2^8 4-9563 16 3400-0 625-00 •98125 9 13-0 4-6406 15 3187-5 666-67 •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 3^385S 11 2337-5 909-09 •98750 9 14-0 30741 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 5 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. 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, SOI) Hydrated nitrate, (NH^ ; HO, N0^) 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 And the chloride of potassium contains - KCl. of ammonium contains NH^Cl. — sulphide " - KS. — sulphide " NH^S. — sulphate of potassa " - KO, SO'-*. — sulphate of ammonia - NH^O, SOI — nitrate " *' - KO, No^ — nitrate " NH^O, NOl — carbonate " " - KO, COl — carbonate " 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 arc primary, secondary, or tertiary nitrides, according as one, two, or three equivalents of the ammonia are replaced. When the substitution of the hydrogen in anmionia is effected by acid radi- cals, the compounds are called amides. I'repar alio II of- A7nvionia. — Ammonia, is obtained by the decomposition of one of the 81 AMMONIA, OAKBONATE OF. salts of ammonia, cither the chloride of ammonium, NH*'C1, (sal ammoniac,) or the sul- phate, by a metallic oxide, e. g. lime. NIPCl + CaO, no = CaCl -[- NH^ -\- 2II0. 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 drieil by passing it through a bottle containing lime. Chloride of calcium must not be employed in the desiccation of ammonia, since the ammonia is absorl>ed by this salt, producing a curious compound, the chloride of caliummonium, N -! p '- CI, being, iu fact, one of those substitution-compounds before alluded to. The giiscous ammonia must be collected over mercury, on account of its solubility in water. This operation is earned 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 WooH'e'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 " Pharmacopeia " 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 0-9G0, 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, Picolinc is detected by its peculinr odor. Naphthaline is discovered not only by its odor, but may also be separated Ijy 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. Ammonia, liquor. 1856, 1855, 1855, lbs. 23,904 343,609 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 scsquicarbonate of commerce, • 2NH^ 3C0-, ?no = NH^O, CO-; HO, CO'-j-NH-'CO", eqv. 118.) This salt was probably known to Kaymond Lully and Basil Valentine, as the chief constituent of putrid urine. The real distinction between ammonia and i'js carbonate was pointed out by Dr. Black. AMMONIA, OAEBONATE 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. Tiie 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 fg. 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. Jlr. Ilill 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 sesquicarljonate of ammonia obtained by sublimation. The pi'ocess 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 Recce, (January 23d, 184!),) and made to form an important feature in the operations of the British and Irish Peat Com- pany. The first part of Mr. Recce'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 otiier products from peat. For this purpose, a blast furnace with suital)le condensing apparatus is used. The gases, on their exit from the condensing apparatus, may bo 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 paraifine and oils for lubricating machinery, «fcc. ; and the other products may be made available for evolving aumionia, wood spirit, and otlur matters by any of the existing processes. Dr. Hodges, of Belfast, states that in his experi- ments he obtained nearly 22 -J lbs. of sulphate of ammonia from a ton of peat. Sir Robert Kane, who was employed by Government to institute a series of exi)erimental 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 184('), the obtaining ammonia from peat by distillation in close vessels, as practised in the carbonization of wood. 8G AMMONIA, NITRATE OF. It will thus be seen that the peat is a source of ammonia, but that this source is a profitable or econoinical one, in a commercial point of view, is a problem in process of solution. Ainiiionia from Sc/iist. — 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 annuoniacal salts by any of th.e usual processes. The obtaining of ammonia from schist forms part of a patent granted to Count de Uompesch, September 4, ISO. Chemical Composition and Constitution. — The true neutral carbonate of ammonia (XirO, 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. c. it contains 2NIP, 300^, 2II0 ; 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, CO^, with a peculiar compound of anhydrous carbonic acid with annnonia itself, (NH^, CO'^) The equation representing its method of preparation will then be, SNII'O, SO'+3CaO, CO^=CNH^O, CO" ; HO, CO-+NIP, COO+HN^O+SCaO, SO', or 3NH^Cl-f 3CaO, CO- = (XH^O, CO", HO, CO^-fNH=, C0-+NH^0)-|-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 c.irbonate 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. Scanlan has also shown that, by treatment with a small (juantity 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 St'LPncRic Acid. Sulphide and hyposulphite of ammonia are sometimes present, and likewise lead, from the chambers into which tlie salt has been sublimed. Other C(tr!jonntcs of Ammonia. — Besides the neutral or monocarbonate of ammonia before alluded to, the true bicarbonate (NH''0, 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 Urc'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 NIP and NO', If heat be applied, the salt is entirely decomposed into protoxide of nitrogen and water ; thus — NH^O, NO' = 2N0 + 4H0. 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 jiroduces 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. (NIPO, SO'.) This salt is found native in fissures near volcanoes, under the name of mossarfnine, a.ssociatcd with sal annnoniac. It also forms in ignited coal-beds — as at Bradley, in Staffordshire — with chloride of ammonium. This salt is prepar(>d 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. Freciuently, instead of adding the acid to the ammoniacal liquor, the crude ammoniacal liquor is distilled in a boiler, cither 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 subseriuently 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 lirst 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 Jidditional acid, with a fresh quantity of ammonia. Frepnration. Modifications in details and patents.- — Since it is in the production of the sulphate of ammonia that tlie modification of Coffey's still, called the ammonia still, 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 iroH. 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 licjuid, 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 eacli 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, tlie su[>ply of steam entering below must bear such proportion to that of the ammoniacal liquid supplied above, that the hitter may be at a boiling temperature in tlic upper part of the apparatus.* The use of this apparatus has been patented in the name of Mr. W. E. Newton, Nov. 9, 1811. iMr. 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. T, 1850, another method of saturating the ammonia with ♦ Pliarm. Joiiriuil, xiii. ('4. 88 AMMONIUM. the acid by passing tlie crude ammonia vapor, obtained by heating the ammoniacal lifnior of the gas-works, in at the bottom of a liigh tower filled with coke, whilst the suliiluuic 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 suri'ace. Dr. Kichardson (patent, Jan. 2(i, 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 i)asses sulphurous acid through the gas liciuor, and finally oxidizes the sul- phite thus obtained to the state of sulphate, by exposure to the air. (Patent, Aug. 12, 1S52.) Michiel's mode of obtaining sulphate of ammonia, patented April SO, 1850, is as fol- lows : — The ammoniacal liquors of the gas-works are combined with sulphate and oxide of lead, which is obtained and jjrepared 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 *lie lower to the upper. The galena or sulphuret of lead, previously ground, is then spread over the surface ol'.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 Mitschcrlich, 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 boihng 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." Usea. — 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 material 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. AMMOXIUM. (NIP.) The radical supposed to exist in the various salts of ammonia. Thus Niro is the oxide, NirC'I the chloride, of ammonium. Ammonium constitutes one of the best established chemical tvpes. 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 t)y the evolution of heat and even light. The chlorine combines with the hydrogen to produce hydrochloric acid, which 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. Mdnufncture of Sal Anunoninc from Gas ]A the charge of dry coarsely crj^stallizcd sal am- moniac. These pots are heated from below and by flues round the siiies. The l)ody 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 AMMOiflUM, CHLORIDE 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. 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 hydrocai'bons, diminish the purity of the product. In consequence of this incomplete subUmation, a conical mass (shown in Jig. 29) is left behind, called the " yolk." After 29 cooling, the dome of the pot is taken off, and the attached cake carefully removed. This cake, which is from 3 to 5 inclics thick, is nearly pure, only requiring a little scraping, whore it was in contact with tlie doiuc, 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, tlie 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. NIPO SO' + NaCI = NirCl+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 l)ye product in the preparation of chlorine, for the manufacture of chloride of lime : crude chloride of iron may be used in the same wav. AMMONIUM, CHLORIDE OF. 91 Mr. Laming patented in July, 1843, the substitution of a solution of chloride of calcium for treating the crude gas liiiuor, 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 Hal 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 carljonate 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 yielcf 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 tlie 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 otiier 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 alwa_ys present in this excrement, by v/hich it is converted into carbonate of ammonia. By treating stale urine with hyhroehloric acid, sal ammoniac separates on evaporation. Properties. — Chloride of ammonium (or sal ammoniac) usually occurs in commerce in fil)rou3 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 cva])orat- 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 1-4;"), and by heating it sublimes without undergoing fusion. It has a sharp and acrid taste, and one part dissolves in 2-7"2 parts of hot, or in an ecjual 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 acjueous solution, and by the copious evolution of ammonia on mixing it with lime, as well as the production of the yellow precipitate of the doul)le chloride of ammonium and patinum (NIPC, PaCl-) 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 ammoniura, and appears to exist in the salt in the form of a double compound (probably of Fe, CI J\H''C1, analo"-ou3 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 annnoniac, 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 tisual 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 KH'' CI Fe'^Cl'. A vcrv simple method of removing the iron, suggested by Mr. Brewer, consists in pass- ing a fewbubblcs of chlorine gas through the hot concentrated solution of the salt, by which the i)rotochloridc of iron is converted into the perchloride. 2Fe CI + CI = Fe'Cl'. 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-Cl' + 3NH^0 = Fe'O^ + 3NH*C1. The sesquioxide of iron, which is of course present in the form of a brown hydrate, is fdtcrcd oil" or separated by dccantation, 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. l^xrs. — 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, IIS. This solution is extensively employed as a re-ngent 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 tcrsulphide, Nn''S', and the pcntasulphide, 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 arc solul)lc in water without decomposition. Ammonia combines with all the other inorganic and organic acids, the name of which is "legion;" but for an accoiuit of these bodies we must refer to the "Dictionary of Chemistrv," as they have but few a]>plicati()ns 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. AMYGDALIXE. (C" II"' NO" -f- 6110.) 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 Primus padus, and in the young sprouts of the F. domestica. It is also found in the sprouts of several species of Sorbm, such as S. aucuparia, S. tormi- nalia, 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 milkj', 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 : — ^ C^" H" NO" 4- 4H0 = C" H" 0' + C" HN + 2C'^ IP" 0'-. 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. Tlie 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 pressed 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 7 feet square. In the centre of this is a cavity for containing tlic fire. A vertical brick wall is built on one side of the hearth, which supports the dome, and a low chimney 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 Ijy 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 l)y small coals, which are thrown upon a kind of oven maath, 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 tlie 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, (arscnitc of silver.) The phosphate of soda produces a yellow precipitate 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. T7ie lieduction Test. — Any portion of the suspected matter, being dried, is mixed with equal parts of cyanide of pota-sium and carbonate of potash, both dry. This mixture is to be introduced into a tube terminating in a bulb, to yhich heat is applied, when metallic arsenic sublimes. (i. Mnrx}i\'i Teat. — 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 stomacli, 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, b, is passed air-tight, and through the ARSENIOUS 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 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, ,- -^ ^ — Q - 40 with tube 1^ "3 6 t2i Calder Cast-iron, No. 1. Hot Blast. Blaenavon, No. 1. Cold Blast. Apedale, No. 2. Hot Blast. .•«£ £«& i-C » 2 ^ ft a is vh a Oi-l 5 == ft -5 in 5 .a a li tc(5 5 <« a Ol-I X a li ci si gh Barley. — This variety is chiefly cultivated in the High- lands of Scotland, and in the Lowlands on exposed inferior soils. Victoria. — A superior variety of the old bigg, compared with which it produces longer straw, and is long-eared, often containing 70 or 100 grains in each. Instances have been known of its yielding 13 quarters per acre, and weighing as much as 96 lbs. per bushel. Beyond these there are, the winter black ; the vnnter white ; old Scottish foiir-rotved ; naked, r/oldcn, or Italian ; Suffolk or Norfolk, and Short-necked ; cultivated in various dis- tricts, and with varying qualities. BARREGE. a woollen fabric, in both warp and woof, which takes its name from the district in which it was first manufactured — the especial locality being a little village named Arosons, in the beautiful valley of Barreges. It was first employed as an ornament for the head, especially for sacred ceremonies, as baptism and marriage. Paris subsequently be- came celebrated for its barreges, but these were generally woven with a warp of silk. Enormous quantities of cheap barreges are now made with a warp of cotton. BARREL. {Baril, Fr.) A round vessel, or cask, of greater length than breadth, made of staves, and hooped. The English barrel — wine measure contains 31^ gallons. " (old) beer" " 36 " " (old) ale " " 32 " " beer vinegar " 34 " " contains 126 Paris pints. The ale and beer barrels were equalized to 34 gallons by a statute of William apd Mary. The wine gallon, by a statute of Anne, was declared to be 231 cubic inches; the beer gallon being usually reckoned as 282 cubic inches. Tiie imperial gallon is 277-274 cubic inches. The old barrels now in use are as follows :— Wine barrel . - . . - Ale " (London) . - . - Beer " " - . . . Ale and beer, for England . - - The baril de Florence is equivalent to 20 bottles. The Connecticut barrel for liquors is 3H gallons, each gallon to contain 231 cubic inches. The statute barrel of America must be from 28 to 31 gallons. The barrel of flour. New York, must contain either 195 lbs. or 228 lbs. net weight. The barrel of beef or pork in New York and Connecticut is 200 lbs. A barrel of Essex butter is 106 lbs. A barrel of Suffolk butter is 256 lbs. A barrel of herrings should hold 1,000 fish. • A barrel of salmon should measure 42 gallons. 26:1- imperial gallons. 33='76» 36=V5» 34=v;, BAEWOOD. 131 BAROMETER. A name given to one of the most important instruments of meteo- rology. This name signifies a measurer of weight — the column of mercury in the tube of the barometer being exactly balanced against the weight of a column of air of the same diameter, reaching from the surface of tiie earth to the extreme limits of the atmosphere. The length of this column of mercury is never more than thirty-one inches ; below that point it may vary, according to conditions, through several inches. There have been many useful applications of the barometer, but the only one with which this dictionary has to deal appears to be the following : — Barometer, MackwortlCx Undcrciround. — In the goafs, or old workings, of some mines, hollows exist, in which explosive or noxious gases tend to accumulate in considerable quan- tity. When the barometer falls, these gases expand and approach or enter the working places of the mine, producing disastrous results to life or health. To enable the manager of a mine to foresee these contingencies, he has but to construct a small model of such a cavity, and let the expansion or contraction of the gas measure itself. In Jiy. 49, a is a 49 brass vessel, 12 inches long and 1^ inches in diameter, closed at each end. In one end is inserted a copper tube, ^ inch in diameter and 12 feet long, b. A hole, 2 inches in diam- eter, being bored 12 feet deep into the solid coal or rock, the brass vessel is pushed to the bottom of it, and the small tube is closely packed round with coal or clay, c is a glass tube, 4 feet long and \ inch in diameter, in which is placed water or oil. As the external atmosphere presses, the surface of the liquid rises or falls, and the scale is graduated by comparison with a standard barometer. The air contained in the brass vessel a, and copper tube B, is unaffected, or^early so, by temperature, and no correction has to be made for the latter as in the sympiesometer. a and b may be conveniently filled with nitrogen, to pre- vent the oxidation of the metal ; and the surface of the liquid in the glass tube may be made self-registering, either giving maxima and minima, or, by the addition of clock-work, taking diagrams on paper. BARWOOD. Although distinctions are made between sandal or saunders wood, cam- wood, and barwood, they appear to be very nearly allied to each other — at least, the color- ing matter is of the same composition. They come, however, from different places. MM. Girardin and Preisser thus describe this wood : — This wood, in the state of a coarse powder, is of a bright-red color, without any odor or smell. It imparts scarcely any color to the saliva. Cold water, in contact with this powder, only acquires a f;\wn tint after five days' macer- ation. 100 parts of water only dissolve 2-21 of substances consisting of 0-85 coloring matter and of 1-36 saline compounds. Boiling water becomes more strongly colored of a reddish yellow ; but, on cooling, it deposits a part of the coloring principle in the form of a red powder. 100 parts of water at 212" dissolve 8-86 of substances consisting of 7-24 coloring principle, and 1-62 salts, especially sulphates and chlorides. On macerating tlic powder in strong alcohol, the liquid almost immediately acquires a very dark vinous red color. To remove the whole of the color from fifteen grains of this powder, it was neces- sary to treat it several times with boiling alcohol. The alcoholic li(iuid contained O'To of coloring principle and 0-004 of salt. Barwood contains, therefore, 23 per cent, of red coloring.matter ; whilst saunders wood, according to Pelletier, only contains lG-75. The alcoholic solution behaves in the following manner towards re-agents : — Distilled water added in great quantity - Produces a considerable yellow opalescence. The precipitate is re-dissolved by the fixed alkalies, and the liquor acquires a dark vinous color. Fixed alkalies Turn it dark crimson, or dark violet. Lime water Ditto. Sulphuric acid Darkens the color to a cochineal red. 132 BAKYTA, CARBONATE OF. Sulphuretted hydrogen - - - - Acts like water. Salt of tin - " Blood-red precipitate. Chloride of tin Brick-red precipitate. Acetate of lead Dark violet gelatinous precipitate. Salts of the protoxide of iron - - Very abundant violet precipitates. Copper salts Violct-bro^vn gelatinous precipitates. Ciiloride of mercury . . - - An abundant precipitate of a brick-red color. Nitrate of bismuth . . - . Gives a light and brilliant crimson red. Sulphate of zinc Bright-red flocculent precipitate. Tartar emetic - - - - - An abundant precipitate of a dark cherry color. Neutral salts of potash - - - - Acts like pure water. Water of barytes - - -. - - Dark violet-brown precipitate. Gelatine Brownish-yellow ochrous precipitate. Chlorine Brings back the liquor to a light yellow, with a slight yellowish-brown precipitate, resembling bydrated peroxide of iron. Pyroxylic spirit acts on barwood like alcohol, and the strongly colored solution behaves similarly towards re-agents. Hydrated ether almost immediately acquires an orange-red tint, rather paler than that with alcohol. It dissolves 19-4'7 per cent, coloring principle. Ammonia, potash, and soda, in contact with powdered barwood, assume an extremely dark violet-red color. These solutions, neutralized with hydrochloric acid, dej)osit the coloring matter in the form of a dark reddish-brown powder. Acetic acid becomes of a dark-red color, as with saunders wood. Barwood is but slightly soluble ; but the difficulty arising from its slight solubihty is, according to Mr. Napier, overcome by the following very ingenious arrangement : — The coloring matter while hot combines easily with the proto-compounds of tin, forming an insoluble rich red color. The goods to be dyed are impregnated with proto-chloride of tin combined with sumach. The proper proportion of barwood for the color wanted is put into a boiler with water, and brought to boil. The goods thus impregnated arc put into this boiling water containing the rasped wood, and the small portion of coloring matter dissolved in the water is inmiediately taken up by the goods. The water, thus exhausted, dissolves a new portion of coloring matter, which is again taken up by the goods, and so on till the tin upon the cloth has become (if we may so term it) satm-ated. The color is then at its bright- est and richest phase. In 1855, the quantity of barwood imported, duty free, was 2,710 tons. Of the barwood imported, 227 tons were re-exported; the computed real value of which was £1,241. BARYTA, CARBONATE OF. The composition of the native carbonate of baryta may be regarded as baryta 77'59 and carbonic acid 22-41. It is fo^d in Shropshire, Cum- berland, Westmoreland, and NorthumVjcrland. The carbonate of baryta is employed in our coh^r manufactories as a biise for some of the more delicate colors; it is also used in the manufacture of plate-glass ; and, in France, it is much used in the preparation of beet-root sugar. Tons. cwts. Alston Moor produced, in 1856 443 10 Fallowfield (Northumlxrland) ditto 1,045 18 BARYTA, SULFHATE OF. The baryte of Brooke and Miller, barytes of Dana and Phillips, Bolognian spar, called also " cawk " and " heavy spar." It is composed of baryta 05-63, sulphuric acid 34-37, with sometimes a little iron, lime, or silica. This salt of baryta is very extensively spread over various parts of the islands. It is worked largely in Derbyshire, Yorkshire, Shropshire, and the Isle of Arran. In 1856 the production was as follows : — From Tons. Derbvshire 8,000 Shropshire ■ 1,200 Bantry (Ireland) 700 Isle of Arran 550 Kirkcudbright 70 It might be obtained in very large quantities in Devonshire, Cornwall, and other places, if the demand for it .sufficiently increased the price so as to render the working of it profit- able. A large quantity of the ground sulphate of baryta is employed in the adulteration of white lead. Paint containing much barytes very soon wa.«hes off the surface upon which it is spread. Lead combines with the oil, and forms, indeed, a plaster. No such combina- tion takes place between the oil and the baryta, hence they soon separate by the action of water. Baryta is employed to some extent in the pyrotechnic art, in the production of flames of a grecnisli character. BATHS. 133 In 1856 we imported — Tone. Baryta, sulphate (ground) --.•-. -- 494 And in the same year we exported — Cwts. Declared Value. Barytes (sulphate and carbonate) - - - 67,751 - - £12,145 BASALT. One of the most common varieties of trap rock. It is a dark green or black stone, composed of augite and felspar, very compact in texture, and of considerable hardness often found in regular pillars of three or more sides, called " basaltic columns." Remarkable examples of this kind are seen at the Giant's Causeway, in Ireland, and at Fin- "al's Cave, in Staffa, one of the Hebrides. The term is used by Pliny, and is said to come from basal, an Ethiopian word signifying iron. The rock sometimes contains much iron. — LyeWs Principles of Geolorpj. Experiments have been made on a large scale to apply basaltic rock, after it has undergone fusion, to decorative and ornamental purposes. Messrs. Chance (brothers) of Birmingham, have adopted the process of melting the Rowley rag, a basaltic rock forming the plateau of the Rowley hills, near Dudley, South Staffordshire, and then casting it into moulds for architectural ornaments, tiles for pavements, &c. Not only the Rowley rag, but basalt, green.stone, whinstone, or any similar mineral, may be used. The material is melted in a reverberatory furnace, and when in a sufficiently fluid state is poured into moulds of sand encased in iron boxes, these moulds having been previously raised to a red heat in ovens suitable for the purpose. The object to be attained by heating the moulds previous to their reception of the liquid material, is to retard the rate of cool- ing ; as the result of slow cooling is a hard, strong, and stony substance, closely resembling the natural stone, while the result of rapid cooling is a dark brittle glass. BASILICOX. The name given by the old apothecaries to a mixture of oil, wax, and resin, which is represented by the Cerat. resince of the present day. BASSORA GUM. A gum obtained from the Acacia lencopklcea, brought from Bas- sora. It has a specific gravity of 1-3591, and is yellowish white in color. BASKETS. Weaving of rods into baskets is one of the most ancient of the arts amongst men ; and it is practised in almost every part of the globe, whether inhabited by civilized or savage races. Basket-making requires no description here. Importations : — In 1856 we imported of rods peeled for basket-making, 123,103 bundles, value £12,309 " rods unpeeled " 157,146 " " 7,858 " " baskets, - - - - 176,730 cubic feet, " 37,580 Of these, 152,777 cubic feet were from France. BATH METAL consists of 3 oz. of zinc to 1 lb. of copper. BATHS. Public baths and wash-houses have now become common amongst us, and with them an increased cleanliness is apparent, and improved health throughout the population. The following is a return of the bathing and washing at the public baths and wash-houses in London, conducted under or in accordance with the Acts 9 and 10 Yict., cap. 74, and 10 and 11 Vict., cap. 61, and of a few out of the similar establishments in the country : — Name of Establishment. Number of Bathers. Number of Washers. Total Kcceipts. JfetropoUn. 1. The Model, Whitcchapcl - 2. St. Martin's-in-the-Fields - 3. St. Marylebone 4. St. Margaret and St. John, Westminster 5. Greenwich 6. St. James, Westminster ... 7. Poplar 8. St. Giles's and Bloomsbury Totals 156,110 155,418 155,827 111,392 61,782 111,870 41,490 8.3,810 42,589 46,337 37,061 66,644 8,815 35,829 10,714 21,051 £ « d. 2,976 7 8 3,007 5 10 2,498 2 3 2,204 12 5 995 11 4 2,038 10 11 845 15 10 1,546 3 877,099 209,040 j 16,112 9 8 Country. Liverpool : — Connvallis Street .... Paul Street George's Pier-head , . - . Hull Bristol .--.--- Preston -•--..- Birmingham --.--. Maidstone 98,460 44,747 45,243 52,142 40,262 29,296 98,396 31,221 11,480 7,579 11,068 10,376 5,547 6,773 I i 1,561 3 2 797 4 4" 1,084 5 6 612 8 7 599 n 2 405 10 5 1,8.54 14 5 318 8 10 134 BAY SALT. The return does not indiide the George Street (Hampstead Koad) and Lambeth estab- lishments, which are not regulated by the public acts. The steady increase of the revenue derived from the baths and wash-houses in London from the commencement of the undertaking in 1846, shows the practical utility of these institutions, aud their efl'ect on the physical and social condition of the industrious classes ; viz. : — The aggregate receipts of nine establishments, inclusive of the George Street establishment, during 1853, amount to 1852. Eight establishments Six establishments Four establishments -..-... Three establishments ------- 1851. 1850. 1849. 1848. 1847. Two establishments 2,896 I - Ditto £ s. d. 18,213 5 8 15,629 5 8 12,906 12 5 9,823 10 6 6,379 17 2 2,896 5 1 3,222 1 5 1846. ) Showing an increase, in 1853 over 1846, of £15,317 Os. 7f7. Those conveniences — now, indeed, become absolute necessities — are extending in every part of the country. Baths, as curative agents, are of very different kinds. Yapor Baths are stimulant and sudorific ; they may be either to be breathed, or not to be breathed. Dr. Pereira has given the following Table, as a comparative view of the heating powers of vapor and of water : — Kind of Bath. Water. Vapor. Not breathed. Breathed. | Tepid bath . . - . Warm bath ... - Hot bath 85' to 92° 92 " 98 98 " 106 96° to 106° 106 " 120 120 " 160, 90° to 100° 100 " 110 110 " 130 Local vapor baths are applied in affections of the joints, and the like. Vapor douche is a jet of aqueous vapor directed on some part of the body. Medicated vapor baths are prepared by impregnating vapor with the odors of medicinal plants. Sulphur, chlorine, sulphurous acid, iodine, and camphor, are occasionally employed in conjunction with aqueous vapor. ITrtDH, tepid, and hot baths are suflSciently described above. BAY SALT. The larger crystalline salt of commerce. BAY, THE SWEET. (Laurvs twbilis.) Bay leaves have a bitter aromatic taste, and an aromatic odor, which leads to their use in cookery. BAYS, OIL OF. This oil is imported in barrels from Trieste. It is obtained from the fresh and ripe berries of the bay tree by bruising them in a mortar, boiling them for three hours in water, and then pressing them. When cold, the expressed oil is found floating on the top of the decoction. Its principal use is in the preparation of veterinary embroca- tions. BEADS. {Grain, Fr. ; Bethe, Germ.) Perforated balls of glass, porcelain, or gems, strung and worn for ornaments ; or, amongst some of the uncivilized races, employed instead of money. Gla&s beads have long been made in very large quantities in the glass-houses of Murano, at Yenicc. Glass tubes, previously ornamented by color and reticulation, are drawn out in proper sizes, from 100 to 200 feet in length, and of all possible colors. Not less than 200 shades are manufactured at Venice. These tubes are cut into lengths of about ^two feet, and then, with a knife, they are cut into fragments, having about tlie same length as their diameter. The edges of these beadj are, of course, sharp ; and they are subjected to a process for removing this. Sand and wood-ashes are stirred with the beads, so that the perforations may be filled by the sand ; this prevents the pieces of glass from adhering in the subse- quent process, which consists in putting them into a revolving cylinder and heating them. The finished beads are sifted, sorted'in various sizes, and strung by women for the market. • In the Jurors' Report of the Great Exhibition of 1851 are the following remarks on this mamifacture : — " The old Venetian manufactures of glass and glass wares fully sustain their importance ; and those of paper, jewellery, wax-lights, Tclvets, and laces, rather exceed their ordinary production. The one article of beads employs upwards of 5,000 people at the principal fabric on the island of Murano ; and the annual value is : t least £200,000. They are ex- BEN OIL. 135 ported to London, Marseilles, Hamburg, and thence to Africa and Asia, and the great East- ei'n Archipelago." The perles a la lime are a finer, and, consequently, more expensive bead, which are prepared by twisting a small rod of glass, softened by a blowpipe, about an iron wire. The preparation and cutting of gems into beads belong especially to the lapidary. The production of beads of Paste, and of artificial Pearls, will be noticed under those heads respectively. In India beads of rock crystal are often very beautifully cut. Dr. Gilchrist states : — Coral beads are in high estimation throughout Hindostan for necklaces and bracelets for women. These beads are manufactured from the red coral fished up in various parts of Asia ; they are very costly, especially when they run to any size ; and they are generally sold by their weight of silver. Coral beads were always favorite articles for ornament even in this country ; and in the " Illustrations of Manners and Expences of antient Times in England," by Nicholls, 1798, we find the following entries from " the churchwardens' accompts of St. Mary Hill, London," containing " the inventory of John Port, layt the king's servant, as after followeth :" — " Item of other old gear found in the house : — - - - - £ s. d. " Item otie oz. and ^ of corall 026 " Jewels for her body. " Item, a pair of coral beds, gaudyed with gaudys of silver and gilt, 10 oz. at 3s. 4J. 1 13 4." (John Port died in 1524.) We imported, in 1856, of coral beads, 2,279 lbs., and of jet beads, 9 lbs. ; while of other kinds uuenumerated, 14,281 lbs. were brought into the United Kingdom. In addition to those, the followbg were our Imports of glass beads and bugles : — Computed real value, lbs. £ Denmark 8,889 - - - 1,111 Hanse Towns 541,580 - - - 67,697 Holland 37,446 - - - 4,681 Belgium 25,704 - - - 3,213 France 6,835 ... 854 Sardinia 18,949 ... 947 Tuscany 10,432 ... 522 Austrian Italy .... 1,493,452 - - - 74,673 Other parts 14,306 - - - 1,564 2,157,593 £155,262 We exported, in 1856, ornamental beads to the value of £21,504. BEAVER, THE. {Castor Fiber.) This animal is caf>tured for its skin, and for the castor, {castorewn,) which is employed medicinally. See Furs. BEBIRINE, or BEBEERINE. (C'^H^'NO".) An alkali discovered by Dr. Rodie, of Demerara, in the bark of the bebeern tree. It was examined more minutely by Madagan and Tilley, and still more recently by Von Planta, who has determined its true formula. It is very bitter, and highly febrifuge. BEECH. {Hi'trc commim, Fr. ; Gemeine Buclie, Germ.) The beech tree (the Fagiis silvatica of Linnasus) is one of the most magnificent of the English trees, attaining, in about sixty or seventy years in favorable .situations, a height of from 70 to 100 feet, and its trunk a diameter of five feet. The wood, when green, is the hardest of British timbers, and its durability is increased by steeping in water ; it is chiefly used by cabinet-makers, coopers, coach-builders, and turners. A substitute for olive oil has been extracted from beech nuts. BELLADOXNA. {Belledame, Fr.) The Atropa Bclladomia, or deadly nightshade. BELL-METAL ORE. Sulphide of Tin. {Etain sulphure, Haiiy ; Zinnkics, Ilaus- mann.) The composition of the ordinary variety of this ore is, Copper 30-0 Iron 120 Tin 26-5 Sulphur 30-5 % 99-0 It is found in many of the Cornish mines, and especially at those of Cam Brea. BEN NUTS. {Ben nnix, Vr. ; Satbriusae, (icTij\.) The tree which furnishes these nuts is the Guilandina inoriuf/n of Linnaeus, a native of India, Ceylon, Arabia, «md Egy])t. BEN OIL. The oil of ben, which may be obtained from the decorticated nuts, is said to be far less liable than other oils to become rancid, and hence it is much used by watch- 136 BENZOIC ACID. makers. At a low temperature, the oil of ben separates into two parts — one solid and one fluid ; the latter only is used for watch-work. On account of its freedom from rancidity, oil of ben is used by Parisian perfumers to form the basis of the Indies antiques of tube- rose, jasmin, &c. See Oils. BENZOIC ACID. (CU^Ol) This acid may be obtained by placing benzoin powdered with sand in an evaporating basin, and above it a paper cap ; on applying heat carefully to the sand, acid vapors arise from the resin, and they are deposited in the form of fine light crystals with the paper cap. Stolze recommends the following process for extracting the acid : — The resin is to be dissolved in three parts of alcohol, the solution is to l^e introduced into a retort, and a solution of carbonate of soda dissolved in dilute alcohol is to be gradu- ally added to it, till the free acid be neutralized ; and then a bulk of water equal to double the weight of the benzoin is to be poured in. The alcohol being drawn off" by distillation the remaining liijuor contains the acid, and the resin floating upon it may be skimmed off and wa.shed, when its weight will be found to amount to about 8(1 per cent, of the raw ma- terial. The benzoin contains traces of a volatile oil, and a substance soluble in water, at least through the agency of carbonate of potash. There are several other methods for obtaining benzoic acid, described in L'rc's "Dictionary of Chemistry." Benzoic acid has no special use in the arts. BENZOLE. Siin. Benzine, benzene, benzol, hydruret of phcnyle, (C'-IP.) The more volatile portion of coal naphtha has been shown by Mansfield to consist chiefly of this sub- stance. It is produced in a great number of reactions in which orgimic bodies are exposed to high temperatures. It may at once be obtained in a state of purity by distilling benzoic acid with excess of quicklime. The lime acts by removing two equivalents of carbonic acid from the benzoic acid. The method of obtaining benzole from coal naphtha will be found fully described under the head of Naphtha Coal. Benzole is also contained in consider- able quantity in bone oil ; but it is accompanied by peculiar nitrogenized volatile fluids, which arc difficult of removal. The latter, owing to their powerful and fetid odor, greatly injure the (juality of the bone-oil benzole. Benzole is an exceedingly volatile fluid, boiling at ordinary pressures at 187" F. Its density is 0-850. Owing to the levity of benzole being regarded by manufacturers as a proof of its purity, it is not uncommon to find it adulterated with the naphtha from the Toibanehill mineral, or Boghead coal, which has a density as low as 0'750. Any benzole having a lower density than 0-850 is impure. Ben- zole is excessively inflammable, and its vapor mixed with air is explosive. Numerous lives have been lost owing to these properties, among them that of Mr. Mansfield, to ■whom we are indebted for an excellent investigation on coal naphtha. Benzole is greatly used in commerce, owing to its valuable solvent properties. It dissolves caoutchouc and gutta jiercha readily, and, on evaporation, leaves them in a state well adapted for water-proofing and many other purposes. Its power of dissolving fatty, oily, and other greasy matters, has caused it to become an article of commerce under the name of benzoline. It readily extracts grease even from the most delicate fabrics, and, as it soon, on exposure to the air, evaporates totally away, no odor rem.ains to betray the fact of its having been used. It dissolves readily in very strong nitric acid, and, on the addition of water, it is precipitated as a heavy oil, having the composition C'^ir'NO^ The latter compound is nitrobenzole ; it is regarded as benzole in which one cfiuivalent of hydrogen is replaced by liyponitric acid. Nitroben- zole, in a state of tolerable purity, is a pale-yellow oil, having a sweetish taste, and an odor gi'catly resembling bitter almonds. Owing to its comparative cheapness, it is employed in perfumery. Nitrobenzole can be prepared with nitric acid of moderate strength, such as is ordinarily obtained in commerce ; but it then becomes necessary to distil the acid and the hydrocarbon together several times. The product so obtained is darker in color, and in other respects inferior to that obtained with highly concentrated acid. By treatment with acetate of protoxide of iron, nitrobenzole becomes transformed into aniline. This change may be eflFectcd, but far less conveniently, by means of sulphide of ammonium. Benzole is extremely valualile in many operations of manufacturing chemistry. It dissolves several alkaloids, and, on evaporation, leaves them in a state of purity. It dissolves quinine, but not cinchonine, and may therefore be employed as a means of separation. Morphia and strychnine are also dissolved by it, but not in great quantity. To obtain many natural alka- loids existing in plants, it is merely necessary to digest the dry extract with caustic potash and then witli benzole. The latter is to be decanted, and then distilled off" on a water-bath. The alkaloid will be left behind in a state well adapted for crystallization or other means of purification. Benzole is becoming much used a.s a solvent in researches in organic chemis- try. Many substances, such as chrysenc and bichloride of naphthaline, crystallize better from benzole than from any other solvent. # Benzole may be employed in many ways for illuminating purposes. It is so easily in- flamed that great care is necessary in using it. It docs not require a wick to enable it to burn. If poured even on an uninflammable surface and a light be applied, it takes fire like a train of gunpowder, and burns with a brilliant flame, emitting dense clouds of smoke, which, soon condensing into soot, presently fall in a shower of blacks. Even on the sur- BERTHOLLETIA. 137 face of water it burns as freely as anywhere else. If a drachm or two be poured on water contained in a pan, and a pellet of potassium be thrown in, the benzole inflames, and rises in a column of flame of considerable height. A method of destroying enemies' shipping has been founded on this principle. In consequence of the smohy nature of the flame of ben- zole, (caused l.)y the comparatively larger perc-entage of carbon,) it is often convenient to burn a mixture of one volume of benzole and two volumes of iricohol. A stream of air driven through benzole becomes so inflammable as to serve for the purposes of illumination. For this mode of using the hydrocarbon, it should be kept slightly warm to assist its vapor- ization. A machine on this principle, of American invention, has been employed to illumi- nate houses. The air is driven through the benzole by a very simple contrivance, the motive power being a descending weight. When quite pure, benzole freezes at 32° to a beautiful snow-white substance, resembling camphor. The mass retains a solid form until a temperature of 40^ or 41" is reached. This property of solidifying under the influence of cold may be made use of to produce pure benzoic from the more volatile portion of coal naphtha. To obtain it perfectly pure, it should be frozen at least three times, the portion not solidifying being removed by liltra- tion through calico. The unfrozen portion contains hydrocarbons, homologous with oletiant gas. Benzole dissolves free iodine and bromine, and has even been used in analysis to sepa- rate them from kelp and other substances containing them. They must of course be sot free before acting with the hydrocarbon. The presence of benzole in mixtures may easily be demonstrated, even when present in very small quantity, by converting it into aniline, and obtaining the characteristic reaction with chloride of lime. For this purpose the mix- ture is to be dissolved in concentrated nitric acid and the nitrobenzole precipitated by water. The fluid is then agitated with ether, which dissolves the nitrocompound. The ethereal solution is mixed with an equal bulk of alcohol and hydrochloric acid : a little granulated zinc being added, hydrogen is evolved, and, by acting in a nascent state on the nitrocompound, reduces it to the state of aniline. The base is then to be separated by an excess of potash, and the alkaline fluid is shaken with ether to dissolve the base. The ethereal fluid being evaporated, leaves the aniline. On adding water and then a few drops of solution of chloride of' lime, the purple color indicative of aniline is immediately pro- duced. {Hofmann.) The writer of this article has by this process detected minute traces of benzole in mixtures consisting almost entirely of homologues of olefiant gas. — C. G. W. BERGAMOT. {Derfjamote, Fr.) The Citrus berr/nmia, a citron cultivated in the centre ami south of Europe. By distillation from the rind of the fruit is obtained the well-known essence of bergamot. This essential oil and the fruit are principally obtained from Flor- ence and Portugal. See Oils, Essential. BERGAMOT. A coarse tapestry, said to have been invented at Bergamo, in Italy, made of ox and goats' hair, with cotton or hemp. BERRY. The term is commonly applied, not only to small fruit, but in some cases to seeds. The following is Professor Lindley's definition of a berry : — " A succulent or pulpy fruit containing naked seeds, or, in more technical language, a succulent or pulpy pericarp, or seed-vessel without valves, containing several seeds, which are naked, that is, which have no covering but the pulp and rind. It is commonly round or oval. But in popular lan- guage, berry extends only to smaller fruits, as strawberry, gooseberry, &c., containing seeds or granules. An indehiscent pulpy pericarp, many-celled and many-seeded ; the attach- ment of the seeds lost at maturity, and the seeds remaining scattered in the pulp." Berries arc used in some of the processes of manufacture, but they are not of much importance. Bai/ Berries. — The fruit of the Laicrus nobilis, or the sweet bay. Both the leaves and the fruit are employed as flavorings. A volatile oil, the oil of sweet bai/, is obtained liy dis- tillation with water; and a fixed oil, by l)ruising the berries, and boiling them for some hours in water ; this oil, called also Laurel f modern biscuit maker, " Africans, Jamaica, tjueen's routs, ratafias, Bath and other sorts of Olivers, exhiljition, ring.^ and fingci-s, i)ic-nics, cuddy," &c., &c., forms a list of upwards of eighty fanciful names, all expressive of articles of difi'erent form, appearance, and taste, made of nearly the same materials, with but little variation in the proportion in which they are used, — the principal ingredients in all being flour and water, butter, milk, eggs, and caraway, nutmeg, cinnamon, or mace, or ginger, or essence of lemon, neroli, or orange- 140 BISCUITS. flower water, called, in technical language, " flavorings." The kneading of these materials is alwavs performed by a kneading or mixing machine. The dough or paste produced is passed several times between two revolving cylinders adjusted at a proper distance, so as to obtain a flat, perfectly homogeneous mass, slab, or sheet. This is transferred to a stamping or cutting machine, consisting of two cylinders, through which the sheet of homogeneous paste has to pass, and by which it is laminated to the proper thickness, and at the same time jiushed under a stamping and docking frame, which cuts it into discs, or into oval or other- wise shaped pieces, as occasion may require. The stamps or cutters in the frame being internally provided with prongs, push the cut pieces of dough, or raw cakes, out of the cut- ting frame, and at the same time dock the cakes, or cut pieces, with a series of holes, for the subsequent escape of the moisture, which, but for these vents, would distort and spoil the cake or biscuit when put in the oven. The temperature of the oven should be so regu- lated as to be perfectly uniform, neither too high nor too low, but just at such a heat as is sufiicient to give the biscuits a light brown color. For such a purpose the hot water oven of Mr. Perkins, or that of Mr. Koland, is the best that can possibly be used. (See Bread.) Roland's oven offers the peculiar advantage that, by turning the screw, the sole of the oven can be brought nearer to the top, and a temperature is thus obtained suitable for baking thoroughly, without burning, the thinnest cakes. One of the most curious branches of the baker's craft is the manufacture of ginger- bread, which contains such a proportion of molasses that it cannot be fermented by means of yeast. Its ingredients are flour, molasses or treacle, butter, common potashes, and alum. After the butter is melted, and the potashes and alum are dissolved in a little hot water, these three ingredients, along with the treacle, are poured among the flour which is to form the body of the bread. The whole is then incorporated liy. mixture, and kneading into a stiff dough. Of these five constituents the alum is the least essential, although it makes the bread lighter and crisper, and renders the process more rapid ; for gingerbread, dough requires to stand over for several days, some 8 or 10, before it acquires the state of porosity which qualifies it for the oven ; the action of the treacle and alum on the potashes, in evolving carbonic acid, seems to be the gassifying principle of gingerbread ; for if carbon- ate of potash is withheld from the mixture, the bread, when baked, resembles, in hardness, a piece of wood. Treacle is always acidulous. Carbonate of magnesia and soda may be used as substitutes for the potashes. * Dr. Colquhoun has found that carbonate of magnesia and tartaric acid may replace the potashes and the alum with great advantage, aflbrding a gingerbread fully more agreeable to the taste, and much more wholesome than the common kind, which con- tains a notable quantity of potashes. His proportions are : 1 lb. of flour, ^ of an ounce of carbonate of magnesia, and -J- of an ounce of tartaric acid, in addition to the treacle, but- ter, and aromatics, as at present used. The acid and alkaline earth must be well diffused tlirough the whole dough ; the magnesia should, in fact, be first of all mixed with the flour. Tlie melted butter, the treacle, and the acid dissolved in a little water, are poured all at once amongst the flour, and kneaded into a consistent dough, which being set aside for half an hour or an hour, will be ready for the oven, and should never be kept unbaked for more than 2 or 3 hours. The following more complete recipe is given by Dr. Colquhoun for making thin gingerl)read cakes : — Flour 1 lb., treacle 4 lb., raw sugar -^ lb., butter 2 ounces, carbonate of magnesia ^ ounce, tartaric acid ^ ounce, ginger ^ ounce, cinnamon ^ ounce, nutmeg 1 ounce. This compound has rather more butter than common thin ginger- bread. In addition to these, yellow ochre is frequently added by cheap gingerbread- makers, and altogether this preparation, more generally consumed by children, is very objectionable. " Puff-paste " is a preparation of flour and butter, which is in great demand not only at the pastry-cooks', but in almost every private family. Take a certain quantity of flour, say half a pound, put it upon a wooden board, make a hole or depression in the centre, and mix it with somewhat less than half a ]iint of cold water, so as to make a softish paste ; dry it off from the board by shaking a little flour over and under, as is well known, but do not " work it " more than you can help. Take now a quarter of a pound of fresh butter, which sliould be ax hard as posxihle, (and therefore it should be kept in as cold a place as practi- cable, the ice closet, if procurable, being the best place,) and squeeze out all the water, or buttermilk which it contains, by kneading it with one hand on the board. This operation is called in French " martirr le hoirrr." Roll now the paste prepared as above into a flat, thick, square slab, extending about or 7 inches ; lay the pat of butter, treated as above, in the middle of the slab of paste, and so wrap the butter up into it by folding the sides of the paste all round over it ; roll the whole mass gently with the rolling-pin, so as to form a thick sheet, put it upon a tin plate, or tray, cover it with a linen cloth wetted with water as cold as possible, and leave the whole at rest for about a quarter of an hour in a cold place. At the end of that time, roll the mass with the rolling-pin into a sheet about 15 or IG inches long, and fold it into three, one over the other; roll it out again into a sheet as before, and again fold it into three, one over the other, as before, and repeat this operation BISMUTH. 141 once more, making three times in all. Put the square mass, with a wet cloth upon it, in a cold place for another quarter of an hour, as before, and at the end of that time roll it out with the rolling-pin, and fold it into three, one over the other, as above ; and do this once more, making five times in all, after which the paste is ready for use. Care must be taken, during the rolling, continually to dust the board and the paste with a little flour, to prevent sticking. The paste may now be placed in the dish, or tins, in which it is to be baked, taking care to cut the protruding edges with a pointed and sharp knife, so as to leave the paste alL round with a clean cut edge, for otherwise it will not puff up or sivell. The thick edges of pies and tarts are made by cutting strips of the paste with the knife, and carefully laying them on all round, taking care to leave the edr/es quite sharp. The pre- pared articles are then put in an oven, previously brought to a good heat, and the elastic vapor disengaged from the butter and water will at once cause the paste to swell into parallel layers of great tenacity, and apparcntli/ light, but really very heavy, since each of these thin laminai is compact and distinct. PuiF-paste is indigestible. It is essential to the success of the operation, that the floor of the oven should be hot. — A. N. BISMUTH. {Bismuth, Fr. ; Bisimdh, Germ.) The following are the principal ores of bismuth ; the first is the source of the metal used in the arts : — Bismuth, Native, is whitish, with a faint reddish tinge, and a metallic lustre which is liable to tarnish. Streak, silver-white. Hardness, 2 to 2'5 ; specific gravity, 9-72Y. It is brittle when cold, but slightly malleable when heated. It generally occurs in a dendritic form. It fuses readily at 476" F. Beautiful crystals can be formed artificially by fusion and subsequent slow cooling. Native bismuth has been found associated with other minerals : in Cornwall, at Huel Sparnon, near Redruth, when that mine was worked ; at Trugoe Mine, near St. Colomb, ((Jregg,) and at the Consolidated Mines, St. Ives, Caldbeck Fells, in Cumberland, with ores of cobidt. Bismtitldne, or sulphuret of bismuth, occurs either in acicular crystals, or with a foli- ated, fibrous structure. It is isomorphous with stibnite. Hardness, 2 to 2'5 ; specific gravity, 6-4 to 6'9. It is composed of bismuth, 81"6 ; sulphur, 18'4. It fuses in the flame of a candle. Bismuthine occurs in Cornwall, at Botallack, and associated with tin at St. Just, and with copper at the mines near Redruth and Camborne. Bismuth Ochre. — A dull earthy mineral, found in the Royal Restormel Iron Mine, and in small quantities in the parish of Roach, in Cornwall. Its composition is stated by Lam- padius to be : — Oxide of bismuth - -80 '4 Oxide of iron .-..-..-.. 5-1 Carbonic acid 4"1 "Water 31 Telluric Bismuth. — Tetradymite, — occurs in Cumberland, at Brandy Gill, Carrock Fells, (Gregg.) Its composition is : — Bismuth 83-30 Tellurium 6-65 Sulphur G-13 Selenium ". - 1.22 Acicular Bismuth. — Aikinite — called also Xeedle Ore, and the plumbo-cupriferous sulphide of bismuth — is composed of sulphur, 10 ; bismuth, 34-02; lead, 35-09; copper, 11-79. Carbonate of Bismuth. — Bismutite. This ore is composed of a mechanical mixture of the carbonates of bismuth, of iron, and of copper. Cupreoics Bismuth. — Tannenite, is sulphur, 18-83; bismuth, 62-10 ; copper, 18-72. This metal is also found associated witli selenium and tellurium. Bismuth may be regarded as the most remarkable of the dia-magnetic bodies, standing, indeed, at the head of the class, in the same way as iron does at the head of the magnetic order of substances.* In lire's " Dictionary of Chemistry " will be found various methods for the determina- tion of bismuth. The following processes, however, appear so useful as to warrunt their insertion in this place : — To detect small quantities of lead in Ijisnmth, or in bisnnilh com- l)()unds. Chapman brings the somewhat flattened head, reduced l)efore the blowpipe, in contact with some moist basic nitrate of tero.xide of bismuth, when, in a short time, in con- sequence of the reduction of the bismuth ))y the K-ad, arborescent sprigs of bismuth are formed around the test specimen. Since zinc and iron interfere with this reaction, they must 1)0 previously removed, the former by fusion with soda, the latter with soda and borax, in the reducing flame. * Consult Do la Rive's Treatise on Electricity, translated by Charles V. Walker, P. R. S. 142 BITTER PRINCIPLE. Lead and bismuth can easily be quantitatively separated from each other by the follow- ing method, proposed l)y Ullgren : — The solution of the two metals is precipitated by car- bonate of ammonia, and the carbonates are then dissolved by acetic acid, and a blade of pure lead, the weight of which is ascertained beforehand, is plunged in the solution. This blade must be completely immersed in the liquor. The vessel is then corked up, and the experiment is left for several hours at rest. ^The lead precipitates the bismuth in the metallic form. When the whole of it is precipitated, the blade of lead is withdrawn, washed, dried, and weighed. The bismuth is collected on a filter, washed with distilled water which has been i)reviously boiled, and cooled out of contact of the air ; this metal is then treated with carbonate of ammonia, and the precipitate which is left, after washing and ignition, is then weighed. The total lo.«s of the metallic lead employed indicates how much oxide of lead must be subtracted from the total weight of the protoxide of lead obtained. — £. PeHijot''s Edition of Rose. Oxide of bismuth can be separated, by means of sulphohydric acid, from all the oxides which cannot be precipitated from an acid solution by this reagent. Yet, when the precipi- tate of sulphide of bismuth is intended to be made by moans of sulphohydric acid, it is necessary to take care to dilute with water the solution of the oxide of bismuth. But as the .solutions of bismuth are rendered milky by water, acetic acid should first be added to the liquor, which prevents its beconiing turbid when water is poured into it. — Roue. BITTER PRINCIPLE. {Amcr, Fr. ; Bitterstoff, Germ.) The " bitter principles " consist of bodies which may be extracted from vegetable productions by the agency of water, alcohol, or ether. These are not of much importance in the arts, with a few ex- ceptions. Lnpulin. — For example, the bitter principle of the hop is used for preserving beer. It is a reddish-yellow powder, obtained from hops by digestion in alcohol, which is evaporated ; then the extract is dissolved in water, and the fluid saturated with lime. This is evaporated, and the residuary ma.ss treated with alcohol or ether. Qitanain is the bitter principle of quassia ; Absinthin^ that of wormwood ; and Gen- iianin, that of gentian, &c. BITUMEN, or ASPIIALTUM. Bitumen comprises several distinct varieties, of which the two most important are asphaltum and naphtha. Axphaltum is solid, and of a black, or brownish-black, color, with a couchoidal brilliant fracture. Kaphtha. — Liquid and colorless when pure, with a bituminous odor. There are also the eartht/^ or daggy mineral pitch — petroleum — a dark-colored fluid variety, containing much naphtha, and maltha, or mineral tar. Bitumen in all its varieties was known to the ancients. It was used by them, combined with lime, in their buildings. Not only do we find the ruined walls of temples and palaces, in the East, with the stones cemented with this material, but some of the old Roman cas- tles in this country are found to hold bitumen in the cement by which their stones are secured. At Agrigentum it was burnt in lamps, and called " Sicilian oil." The Egyptians used it for embalming. — Dana. Sjirings of which the waters contain a mixture of petroleum, and the various minerals allied to it — as bitumen, asphaltum, and pitch — are very numerous, and are, in many cases, undoubtedly connected with subterranean heat, which sublime the more subtle parts of the bituminous matters contained in rocks. Many springs in the territory of Modena ami Parma, in Italy, produce petroleum in abundance ; but the most powerful perhaps yet known are those of Irawadi, in the Burman empire. In one locality there are said to be 520 wells, which yield annually 40,000 hogsheads of petroleum. Fluid bitumen is seen to ooze from the bottom of the sea on both sides of the island of Trinidad, and to rise up to the surface of the water. It is stated that, about seventy years ago, a spot of land on the western side of Trinidad, nearly half-way between the capital and an Indian village, sank suddenly, and was immediately replaced by a small lake of ))itch. In this way, probably, was formed the celebrated Great Pitch Lake. Sir ("harks LycU remarks : — " The Orinoco has for ages been rolling down great quantities of woody and vegetable bodies into the surrounding sea, where, by the influence of currents and eddies, they may be arrested and accumulated in particular places. The frequent occurrence of earthquakes, and other indications of volcanic action in those parts, lend countenance to the opinion that these vegetable substances may have undergone, l)y the agency of subterranean fire, tho.«e transformations or chemical changes which produce petroleum ; and this may, by the same causes, be forced up to the surface, where, by exposure to the air, it becomes inspissated, and forms the different varieties of pure and earthy pitch, or asphaltum, so abundant in the island." The Pitch Lake is one and a half miles in circumference ; the bitumen is soliil and cold near the shores, but gradually increases in temperature and softness towards the centre, whore it is lioiling. The solidified l)itumen appears as if it had cooled, as the .surface boiled, in large bubbles. The ascent to the lake from the sea, a distance of three-quarters of a BLACK FLUX. 143 mile, is covered with a hardened pitch, on which trees and vegetabes flourish ; and about Point la Braye, the masses of pitch look like black rocks among the foliage : the lake is underlaid by a bed of mineral coal. — Jfaiiross, quoted by Dana. The Earl of Dundonald remarks, that vegetation contiguous to the lake of Trinidad is most luxuriant. The best pine-apples in the West Indies (called black pines) grow wild amid the pitch. Asphaltum is abundant on the shores of the Dead Sea. It occurs in some of the mines of Derbyshire, and has been found in granite, with quartz and fluor spar, at Poldicc, in Cornwall. There is a remarkable bituminous lime and sandstone of the region of Bechcl- l)ronn and Lobsann, in Alsace. From the observations of Daubree, we learn that probably this bitumen has had its origin as an emanation from the interior of the earth ; and indeed, in Alsace, with the great elevated fissure of the sandstone of the Vosges, a fissure wliich was certainly open before the deposit of the Trias, but was not yet closed during the ter- tiary epoeh, affording during this latter, moreover, an opportunity for the deposition of spathic iron ore, iron pyrites, and heavy spar. — Annales des Mines. Elastic Bitumen, called also mineral caoutchouc and elatcrite, was first observed in Derbyshire, in the forsaken lead mine of Odin, by Dr. Lister, in 167-3, who called it a sub- terranean fungus. It was afterwards described by Hatchett. The analysis of this variety, by Johnston, gave the following as its composition : — Carbon, 83 '47 Hydrogen, 13-28 Two descriptions of elastic bitumen were analyzed by M. Henry, fils, (" Ann. des Mines.") He states the English to have been in brown masses, slightly translucid, of a greenish color, soft, elastic, burning with a white flame, and giving off" a bituminous odor, and of specific gravity 0-9 to r23, and obtained from Derbyshire. The French elastic bitumen generally resembled the English, excepting that it was opaque, and floated on water. It was discovered at the coal mines of Montrelais. Carbon . - . - . • Hydrogen - - - - - Nitrogen ----- Oxygen Of ordinary bitumen, we have analyses of two specimens ; tained his sample from the Auvergne ; and the other by Boussingault, which was a Peru- vian specimen : — Auvergne. reruvinn. Carbon 76-13 - - - 88-63 Hydrogen 9-41 - - - 9-69 Oxygen 10-34 [ j English. French 0.5225 - - - 0-5826 00749 - - . 0-0489 0-0015 . . - 0-0010 0-4011 0-3675 1-0000 1-0000 wo specimens : one by Ebelmen, who ob Nitrogen 2 Ash 1-80 -34) .32 f 100-00 100-00 BLACK BAND. A variety of the carbonates of iron, to which attention was first callccl by Mr. Mushet, at the commencement of the present century. The iron manufacture of Scotland owes its present important position to the discovery of the value of the lilack band iron stone. This ore of iron is also found in several parts of the coal basin of South Wales, and in the north of Ireland. See Iron. Chemical examination of the black band, from the neighborhood of Airdrie, about ten miles east of Glasgow, gives the following composition : — Carbonic acid - - 33-17 Protoxide of iron 5303 Lime 333 Magnesia 1-77 Sihca 1-10 Alumina 063 Peroxide of iron 0-23 Bituminous matter 3 03 Water and loss Til 100-00 BLACK FLUX. An intimate mixture of charcoal and carbonate of potash, obtained by calcining bitartratc of potash. Generally, the crude tartar of conunerce is tised for this purpose. 144 BLACKING FOE SHOES. BLACKING FOR SHOES. According to the " Scientific American," a good paste blacking is made of 4 lbs. of ivory black, S lbs. of molasses, 9 oz. of hot sperm oil, 1 oz. of gum urabic, and 12 oz. of vinegar, mixed together, and stirred frequently for six days ; it is then fit for use. Blacking consists of a black coloring matter, generally bone black, and substances that acquire a gloss by friction, such as .«ugar and oil. The usual method is to mix the bone black with sperm oil : sugar, or moliu«ses, with a little vinegar, is then well stirred in, and strong sulphuric acid is added gradually. The acid produces suljihate of Hme and acid phosphate of lime, which is soluble : a tenacious paste is formed by these ingredients, which can be smoothly spread ; the oil serving to render the leather pliable. This forms a liquid blacking. Paste blacking contains less vinegar. In Germany, according to Licbig, black- ing is made by mixing bone black with half its weight of molasses, and one-eighth of its weight of hydrochloric acid, and oifb-fourth of its weight of strong sulphuric acid, mixing with water, to form an unctuous paste. — Report of the Progress of Science and Mechan- ism^ Kew York. BLAST HOLES. A mi)iing term. The holes through which the water enters the bot- tom of a pump in the mines. BLEACHING {Blanchcmcnf, Fr. ; Bleichen, Germ.) is the process by which the textile filaments, cotton, flax, hemp, wool, silk, and the cloths made of them, as well as various vegetable aiid animal substances, are deprived of their natural color, and rendered nearly or altogether white. The term bleaching comes from the French verb hlanchir, to whiten. The word blanch, which has the same oi-igin, is applied to the whitening of living plants by causing them to grow in the dark, as when the stems of celery are covered over with mould. The true theory of bleaching has not been entirely agreed upon, but there can be little doubt of the principal operations. It is known that oxygen deprives substances of color ; this may be performed by many high oxides ; by nitric acid, manganic and chromic acids, chlorous acid, and even lower oxides which liold their oxygen lightly, as hypochlorous acid. The same effect may be produced by chlorine, bromine, and iodine. It has been said that chlorine unites with the hydrogen of the water which is present, gives off oxygen, and so acts just as oxygen would. Davy found that it would not act in dry air, so that water was needful : but Dr. "Wilson found that it would act, although slowly, in dry air, if exposed to the rays of the sun. This might show that water is not necessary in order to supply oxy- gen, but only to allow the chlorine to be brought into thorough contact with the coloring matter. It has also been supposed that the chlorine removes the hydrogen, or, rather, sim- ply takes its place by an act of substitution. Now, whether the chlorine or the liberated oxygen removes the hydrogen, the result will be the same — the destruction of the com- pound. Chlorine so readily performs these changes, that we should at once decide on call- ing it the active agent, were it not for the fact that oxygen acts so readily, even when chlorine is not present : for example, peroxide of hydrogen, as well as the oxides just men- tioned, and ozone also, which has no chlorine to help it. It is, then, certain that oxidation bleaches ; and it is certain that dehydration bleaches, if performed by chlorine, and that the sun aids it by its active rays. We know also that water aids it : water aids bleaching or oxidation by air, partly because it contains air in solution. It aids also the bleaching per- formed by solutions in contact with porous bodies, because these bodies have a power of OGndensing gases in their pores and of compelling combinations. The next question is, Does it aid the bleaching by chlorine in the same way, by assisting the union mechanically, or by decomposing water? Chlorine acts slowly, unless water be present. The theory, therefore, docs not demand the decomposition of water, and the known powerful affinities of chlorine do not require to be supplemented by oxygen. But, in order to see exactly the state of the case, let us look at the action of chlorine in hypochlorites or in chloride of lime, and we find that it is a direct oxidation. We obtain by it peroxides of metals, and not chlorides. Here we seem to be taught directly by experiment, that bleaching by hypo- chlorites is an oxidation of the coloring matter. Bleaching >)y moist chlorine may there- fore be looked on as the same ; indeed, we oxidize by it ; but in such cases we may obtain the base at the same time united to chlorine, giving another turn to the question, as Kane showed. The oxidation theory, therefore, seems to be sufficient when water is present. We are, however, finally to deal with dry chlorine in the sun ; and in that case it is fair to conclude that it acts by direct combination with hydrogen or the coloring matter, or both. We have, then, two modes of bleaching ; but the usual mode in the air becomes by that explanation an oxidation, and the direct action of chlorine obtainable only with difliculty. When sulphurous acid is used, another phenomenon may be looked for, as wc find a sub- stance whose chief quality is that of deoxidizing. The removal of oxygen also decomposes bodies, and sulphuretted hydrogen can scarcely l)e supposed in act in any other way. Sul- phurous acid, when it decomposes sulphuretted hydrogen, really acts as an oxidizing agent, and we can therefore imagine it as such in the bleaching process. Investigation has not told us if it enters into combination as SO^, and, like oxygen, destroys color, altering the compound by inserting itself. BLEACHING. 145 We may fairly conclude that the processes by chlorine and sulphurous acid are per- formed in a manner as different as the mode in which a salt of ammonia acts on chlorine or an oxacid, or, in Dr. Wilson's general terms, " Specific differences may be expected to occur with all the gases named, as to their action on any one coloring matter, and with different coloring matters, as to their deportment with any one of the gases." — Trans. Ji. S. E., 18-48. It has been attempted to introduce manganates, chromates, chlorates, chlorochroniic acid, and sulpliites, but without success, as bleaching agents. General Process of Bleacldng. — The process of bleaching, from what we have seen, resolves itself into treatment with alkalies and the action of chlorine or of light. In de- scribing the operations, they seem to be very numerous ; but, as explained, some require to be repeated gently, instead of being finished by one decisive operation, so as not to injure the fibre ; and some are intermediate operations, such as the frequent washings needed in passing from one process to the other. The alkaline solution in which the goods are boiled does not contain above 250 lbs. of carbonate of soda to 600 gallons, but nearly always less. Lime is, however, used much more frequently than soda, which it will be seen is only em- ployed in tiie second process, and the third, if there be one. It is less hurtful to the cloth, and is much cheaper than the alkalies. The chloride of lime is used at i Twaddle, or 1002'5. It is not considered so important now as formerly, and where 300 lbs. were formerly employed, 30 to 40 are now used. The goods are made nearly white by the alkalies. The chlorine gives only the last finish, and is sometimes used to whiten the ground on colored goods. The whole process may be ex- pressed thus : — Wash out the soluble matter ; boil with lime to dissolve still more, and to make a fatty compound with the oily matter ; wash out the lime by acids ; wash out the fat with a soda soap ; clear the white by chloride of lime. The impurities in the cloth have a certain power of retaining color upon them. Mud and dirt, as well as grease, gluten, and albuminous matters, have this property, and fatty soaps, such as lime compounds of fatty acids. The pure fibre, however, has no power of taking up solutions of such coloring matter as madder. When, therefore, it is desired to try the extent to which cloth has been bleached, it is dyed or boiled up with madder ex- actly as in the process of dyeing. It is then treated with soap, as the madder-dyed goods are treated, and if it comes out without a stain, or nearly pure white, the goods are ready. Dyers or calico-printers who dye printed goods are exceedingly particular as to the bleach- ing, the dyeing and printing having now approached to such exactness, that shades invisible to any eye not very much experienced are sufficient to diminish in a material degree the value of the cloth. Any inequality from irregularity of bleaching, which causes a similar irregularity of dyeing, is destructive to the character of the goods. Many patterns, too, have white grounds ; these grounds it is the pride of a printer to have as white as snow. If delicate colors are to be printed, they will be deteriorated if the ground on which they are to be printed is not perfectly white. Old Method's still in use. — As a specimen of the older processes, we shall give the fol- lowing, adding afterwards a minute account of some of the plans adopted by the most suc- cessful bleachers. When grease stains do not exist, as happens with the better kind of muslins, or when goods were not required to be finely finished, the following has been adopted : — After singeing, 1. Boiling in water. 2. Scouring by the stocks or dash-wheel. 3. Bucking with lime. 4. The bleaching property so called, viz., passing through chlorine or crofting. 5. Bucking or bowking with milk of lime. These two latter processes em- ployed alternately several times, till the whole of the coloring matter is removed. 6. Sour- ing. V. Washing. Tfie Processes used in Bleaching. Singcinrj. — The singeing is performed by passing the cloth over a red-hot plate of iron or copper. The figure 50 shows this apparatus as improved by Mr. Thom. At a there is a cylinder, with the cloth wound round it to be singed ; it passes over the red-hot plate at 6, becomes singed, passes over a small roller at c, which is partly immersed in water, and by this means has all the sparks extinguished ; then is wound on to the roller d, when the process is finished. As the products of combus- tion from the singeing are sometimes very unpleasant, they are carried l)y this apparatus into the fire-place, where they are consumed. The arrows .show the passage of these vapors from the surface of the cloth downwards into the hearth, and thence; into the fire. For goods to be finely printed both sides are singed ; for market bleaching, one side. Sometimes, however, singeing is not at all desired. The use of a line of gas jets instead of a red-liot plate, was introduced by Mr. Samuel Hall. It has not, however, found its way generally into bleach works : the plate is pre- ferred. Gas jets are used necessarily in singeing threads. Shearing. — For fine printing, it is by some considered needful to shear the nap of the cloth instead of singeing it. The method is more expensive tiian singeing. Messrs. Mather and Piatt have made a machine which will shear (30 to 80 yards per minute. Vol. III.— 10 146 BLEACHING. 60 BLEACHING. 147 Bucking or BoioUng. — This is the process of boiling goods. It is perfonned in alkaline liquids, generally lime or soda, or both. The kier for bowking is a cylindrical iron vessel, constructed so as to render the boiling free, and prevent the goods from being burnt on the bottom. The kier of Messrs. Mather and Piatt is very complete. The first figure (51) is the kier when shut or screwed down. The second figure (52) is the section of the tier, which is very like that before given ; but in this case it is steam-tight, and heated by steam which issues from a steam pipe communicating beneath the false bottom. The dangers attending the kier before mentioned are by this moans entirely averted, and all the inven- tions winch give the washing liquid a separate and distinct place for heating are at once done away with. An exact description of these kiers is required, a, b, c, d, represent the body of the kier, which is a cylindrical vessel, generally made of cast-iron, but sometimes of wood, or wrought iron. h represents false bottom — a cast-iron grating sometimes covered with boulder-stones, and sometimes with wood ; ly l)ut into a strong upright cylinder, the top screwed down, and the air taken out by an air-i)uiii]). We have no knowledge as to the advantages gained by this process, or whether it has been found actually capable of putting cloth in a condition to be bleached for a very fastidious market. 148 BLEACHING. '%w^^ww^i^^^w^^^i^^^:j^;;rz3Z~7 BLEACHING. 149 Steeping. — Instead of boiling in the kier at first, the goods are sometimes, though now rarely, steeped from one to two days in water, from 100' to 150' F., for the purpose of loosening the gummy, glutinous, and pasty materials attached to the cloth. Fermentation ensues, and this process is dangerous, as the action of the ferment sometimes extends to the goods, especially if they are piled up in a great heap without being previously washed. The spots of grease on the insoluble soaps become thereby capable of resisting the caustic alka- lies, and are rendered in some measure indelible : an eSect due, it is believed, to the acetic and carbonic acids generated during fermentation. Some persons throw spent h-es into the fermenting vats to counteract the acids. The spots of grease are chiefly to be found in hand-loom goods, and the difficulty concerning the fats is not therefore commonly felt where power-loom goods are chiefly used, as in Lancashire. Washing. — The machine made by Mr. Mather {figs. 53 and 54) washes 800 pieces per hour, or 8,000 pieces per day of 10 hours, using 400 gallons per minute, or 120,000 gallons per day, or 20 gallons to a piece. This class of machine is now in its turn superseding the dash-wheel. This washing machine will be understood by the general plan, {fig. 54, and correspond- ing section, fig. 53.)- a and b represent the squeezing-bowls. a is 18 inches diameter and 8 feet 3 inches long ; it is made of deal-timber. (The lapping of strong canvas at a" is for the purpose of giving the " out-coming " pieces an extra squeeze, in order to prepare them for the kiers.) b is 24 Inches diameter and of the same length as a, making 100 revolutions per minute ; it is generally made of deal, sycamore, however, being better, c, d, a strong wooden rail, in which pegs are placed in order to guide the cloth in its spiral form from the edge to the centre of the machine, h, k, the water-trough, through which the piece passes round the roller r. p, {fig. 53,) water-pipe ; i, water-tap ; m, ?«, pot-eyes, which may be adjusted to any angle, to guide and regulate the tension of the piece on entering the machine. I, side frame, for carrying bowls, &c. ; g, engine (with cylinder, 8 inches diameter) and gearing for driving machine ; w, weight'and lever for regulating pressure on the bowl. This machine washes 800 pieces per hour, and requires 400 gallons of water per minute. It will serve also to represent the chemick and souring machine, the only difference being that the bowls are 3 feet 6 inches, instead of 8 feet 3 inches, in length. The chemick and sour are brought by turns into the trough, or into similar separate troughs, by a leaden pipe from the mixing cisterns, and are run in to 6 or 8 inches deep. The washing machine of Mr. Bridson {fig. 55) is worth attention. In its action the course of the cloth in the water is easily seen ; it is chiefly horizontal. This motion had been given by Hellewell and Fearn in 1856 ; but they had a very complicated machine, and they did not attain the flapping motion which is given to the cloth when it becomes' sud- denly loose, and is driven violently against the board a a as often as 6 c and e d are in one line. It is not shown by the drawing that the cloth passes eight times round these wheels. There is a constant stream of water from the pipe /, which is flattened at the mouth about one and a half inches in one diameter, and about ten inches in the other. This machine can wash 900 pieces in an hour. It requires about twice as much water as a dash-wheel but washes seven and a half times more pieces. Its length is nine feet. 55 150 BLEACHING. Souring. — After boiling in the first kier and washing, the goods are soured in muriatic acid of lOlO- specific gravity, or 6^ gallons of the usual acid, which contains 33 per cent, of real acid, mixed with 100 gallons of water. This is equal to 2° Tw. Muriatic acid may be replaced by sulphuric acid of 1024- specific gravity, i. e. 3| gallons liquid acid to lUO of water ; — or the amount of the acid may be doubled in either case, and a shorter time allowed for the souring. The souring is performed in wooden or stone cisterns, where the cloth is laid regularly as it falls over one of the rollers of the calender ; — or it is passed through the acid solution by the movement of the calender in the same manner as described in the process of washing. If this method is used, it is allowed to lie on the stillages from two to three hours to allow the acid to act. The acid decomposes any lime soap formed, and washes out the hme. Hydrochloric or muriatic acid has been preferred in the process described, as the chloride of calcium is so much more soluble than the sulphate. After souring, of course the goods must be thoroughly washed as before. The sixth operation with soda removes the remaining fatty materials. If lime be used, it may be allowed to settle ; and it is better to allow it to do so, and thus to use pure caus- tic soda, which will with the resin remove the impurities in a more soluble form. If, instead of adding 170 lbs. of soda crystals to 600 gallons of water, 4-6 lbs. of liquid caustic soda of specific gravity 1320' were added, the effect would be the same. The solution of resin and carbonate of soda is a half-formed soap, which is considered to act beneficially in moving the soluble matter. It would not appear, from theory, to be capable of doing so well as the soda which has its carbonic acid removed ; but tender goods will not allow the action of caustic soda, and the carbonate is therefore safer. Powder-blcachlnrf. — Chloride of lime is added in stone vessels where the goods are allowed to lie. It is universally called chemick in the manufactories. The strength used at Brickacre is half a degree Twaddle, or 1002-5. This is sometimes very much increased, so as to be even 5° in some establishments, according to the goods bleached ; but it is not safe to allow the cloth to lie long in such strong solutions. In such cases it is needful to pass them rapidly through with the calender, so as to soak them thoroughly, and then to pass them on to the acid, and forward to be washed. It may be remarked that the use of the calender for these operations renders it possible to use strong solutions, even for. tender goods, as there is no time given for injurious action on the fibre. Great care is to be taken to make the solution of the chloride of lime perfectly clear. The powder does not readily wet with water, and it must therefore be pressed or agitated. This may be done by putting it in a revolving barrel with water, until complete saturation of the powder with moisture ; the amount required is then thrown into the cisterns, and the insoluble matter allowed to sink. This insoluble matter must not be allowed to come into contact with the cloth, as it will be equal of course to a concentrated solution of the liquor, and will produce rottenness, or burn the cloth so as to leave holes. "When removing from the trough, the cloth is drawn through squeezing rollers, which press out any excess of chloride of lime. Squeezing. — A squeezing machine, with a small engine attached, is shown in ^17. 56, for the drawing of wliich we are again indebted to the makers, Messrs. Mather and Piatt. d, f represent the squeezing bowls. They are as large in diameter as possible, and are generally made of sycamore ; but the bottom one is better made of highly compressed cot- ton, a, b arc the engine and frame for driving ; ^, frame for carrying bowls ; /, /, com- pound levers for regulating the press use ; s is a screw for the same purpose, and c is the cloth passing through the bowls. The white-squeezers, or tho.se used before drying, should have a box, supplied with hot water, fixed so that the piece may pass through it before going to the nip of the bowl. When the goods are run through, they are carried oft' upon a grated wheelbarrow in a nearly dry state, and transferred to the spreading machine called at Manchester a candroji. In many bleach-works, however, the creased pieces are pulled straight by the hands of women, and are then strongly beat against a wooden stock to smooth out the edges. This being done, a number of pieces are stitched endwise together, preparatory to being mangled. This squeezing machine is small, but, as will be seen, the rollers are introduced, so as to act as long and as rapidly as cloth of whatever length is drawn through them. The following figure (57) represents a pair of squeezers, for sciueezing the cloth after several of the processes named, and are shown as being driven by a small high-pressure engine, a is the fly-wheel of engine ; 6, crank of ditto ; c, frame of engine ; r/, spur-wheels connecting the engine and squeezers ; e and/, sycamore squeezing bowls. The cloth when passed over the steamed rollers is now dry ; but it is not smooth and ready for the market. If the cloth is wanted for printing, no further operation is needed ; but if to be sold a.s white calico, it is finished by being starched and calendered. The starch at large works is prepared by the bleachers themselves. At Messrs. Bridson's it is made with the very greatest care from flour. Of course it would be more expensive for them to buy it, as the manufacturer would dry it, and they would recjuire to dissolve it. They arc able also, in this manner, to obtain the purest starch. This is mixed with blue. BLEACHTN^G. 151 152 BLEACHING. according to the finish of the goods. A roller, which dips into the starch, lays it regularly and evenly on the cloth in the same manner as mordants are communicated in calico-print- in", whilst other rollers expel the excess of the starch. The cloth is then dried over warm cyTi'ndcrs, or by passing into a heated apartment. It receives the final finish generally by the calender ; but muslins receive a peculiar treatment. See Calender, vol. i. Finishing. — Pure starch is not always used for the purpose of finishing. Fine clay, gypsum, or Spanish white, is mixed with the cloth ; and if weight is desired to be given, sulphate of baryta is employed. Mr. John Leigh, of Manchester, has lately patented for this purpose the use of silicate of soda, which, for such goods as are not injured by alkalies, seems to answer the purpose at a very cheap rate. There can, however, be no doubt that too much attention is given to this finish for home goods, or for all purposes which require the goods to be washed ; they assume a solidity of appearance which they do not possess when the finishing material is removed from the pores, and the cloth appears without dis- guise. In some instances, however, this finish is a peculiarity of the goods, and is almost as important as the cloth itself. P'or example : in the case of muslins, when they are dried at perfect rest, they have a rigid inelastic feeling, somewhat allied to that of thin laths of wood, and feel very rough to the touch. They are therefore dried by stretching the cloth, and moving the lines of selvage backward and forward, so as to cause the threads of weft to rub against each other, and so as to prevent them becoming united as one piece. Goods dried in this manner have a peculiar spring, and such thick muslins are for a time possessed of great elasticity. Several pieces folded up in a parcel spring up from pressure like caoutchouc. Mr. Ridgeway Bridson invented an apparatus for giving this peculiar finish to muslins. Formerly it was done entirely by the hand, and in Scotland only. Since the invention of this machine, this trade has become a very important one in the Manchester district. Sometimes goods are finished by the beetle, which acts by repeated hammering. ' This peculiar action has been transferred to a roller by T. R. Bridson, and called the " Rotatory Beetle." It consists of a cylinder having alternately raised and depressed surfaces, and two other cylinders which press' upon it, and alternately press the cloth and give a freedom as it passes between the rollers. This is similar to the rise and fall of the hammers or mallets in the beetling process. Sometimes a stiff finish is wanted ; then muslins are dried in the usual way. Drying. — Figs. 58 and 59 represent a drying machine, with eleven cylinders, each 22 inches in diameter, capable of drying 1,000 pieces of bleached calico in a day. a represents cylinders heated with steam ; v, vacuum-valves in ditto ; /, frame for carrying cylinders ; c, folding apparatus ; s, steam-pipe ; g, gearing. When goods arc dried having a raised pattern, such as brocades, or any other, such as striped white shirting, only one side of the cloth is to be exposed ; the pattern rises up from the heated surfiice on which the cloth is dried. For this reason, cylinders such as those just described cannot be used. Large wheels of cast-iron are employed, consisting of two con- centric cylinders, between which is a closed space heated by steam. The cloth is by this means heated on one side onlv, not passing from cylinder to cylinder, in which case the side next to the heating surface' would be changed every time. The larger the cylinder or wheel, the more rapid is the drying, as there is more surface of cloth exposed to it at a time ; it can, for the same reason, be turned more rapidly round. Well-finished goods will not rise when heated, except on the pattern. Messrs. Bridson have a large business in jacconets for artificial flowers on account of this peculiar finish. They are formed ol a plain cotton cloth, but stand the pressure of hot irons without curling. BLEACHING. 69 153 No essential difference is made in bleaching muslins, except that sometimes weaker solutions are employed for very tender goods. Mr. Barlow makes no difference as a rule in the strength given in describing his process ; with very strong goods, he sometimes uses the liquids stronger. It is desired occasionally to bleach goods which have colored threads woven into them, or colors printed on them. In these cases great caution must be used. It is needful to use weak solutions, but more especially not to allow any one process to be continued very long, but rather to repeat it often than to lengthen it. Tliis may be stated as a general rule in the bleaching of goods. It would indeed be possible to do the whole bleaching in one operation, but the cloth would be rotten. This arises from the fact that, at a certain strength, bleaching liquid or soda is able to destroy the fibre ; but another and less strengtli does not act on the fibre, but only on such substances as coloring matters. This care is needed when printed goods which have a white ground are treated. The white ground takes up color enough to destroy its brilliancy, and soaping does not always remove it. The bleaching then is effected by using bleaching liquor at ^ Twad. Some persons put a Turkey red thread into the ends of the pieces. The original use of this seems to be scarcely known among the manufacturers. It was used as a test of the mode of bleaching employed. If strong solutions be used, which are apt to spoil the cloth, the color of the dyed threads will be discharged. When the separate system is employed, this is evaded easily ; it is the practice to keep the ends containing the red threads out of the liquid, allowing them to rest on the side of the vessel. Sometimes chlorate of potash is used for the same purpose, souring as with the bleaching powder. The colors may, in this manner, be made much more brilliant than before, although a little excess will discharge them. A good deal of the effect may be owing to the better white given to the ground. Besides these processes for bleaching, another was at one time introduced, which consisted of immersing the cloth in a solution of caustic alkali, and afterwards steaming in a close vessel. It is not now in use. Alkali of 1020" specific gravity was used. The new or continuous Process. — This method owes its introduction to David Bentley, of Pendleton, who patented it in 1828. It consists in drawing the goods in one continuous line through every solution with which it is desired to saturate them. This is done by con- necting the ends of all the pieces. The motion of rollers draws the chain of clotli tlius formed in any desired direction, and through any number of solutions any given number of times. We shall allow him to use his own words : Fiff. 60 is an end view of two such calenders, each having two larger rollers n and n 1 , a smaller driving roller c, two racks n and d 1, placed upon two cisterns g and o 1, inside of which cisterns arc two rollers e and k i, wliich rollers have four square ribs upon each, to shake the goods as they pass through the cisterns. At f is a frame upon which the batches of goods are placed upon rollers shown infu/. f.l, where they are marked k, k, k, k. Tiie calender cheeks arc made fast at the feet, at the middle, and to the top of the building, having levers and weights ii to give pressure to the calender bowls. Near the end walls of the building are two rollers, one of which is shown at a ; upon eacli of these is a .soft cord used as a guide for conducting the goods througli the machinery and cisterns. The operation is commenced by jiassing one end of the coi-d through the rollers b and C, down to cistern o, unilcr roller k, through the fin-thermost division of rack n, and again through calender rollers at u and c, repeating the same, but observing to keep 154 BLEACHING. 60 61 K n t^ the cord tight, and to approach one division nearer in rack D each revolution until each division is occupied, when the end must pass over c, under and around b 1, down to and over the guide roller i 3, through the nearest division of rack d 1 into cistern g 1, under roller e i, over guide roller i 2, and again over roller c, under and round B 1. This course must be repeated, observing as bcfoi'e to keep the cord tight, and to receive one division of rack D 1 every revolution, until each division of rack d ] is occupied, when the end must pass over from b 1 under I 4. The cord now forms a sort of spiral worm round and through the machinery and cisterns, beginning at b, c, and ending at the top of B 1 to i 4, the number of revo- lutions being governed by the number of divisions in the racks d and d 1, so that if there were fifteen divisions in each rack, there would be fifteen revolutions under c, round b through g, under E tlirough d, and fifteen revo- lutions over c round n 1, over i 3 through d 1 and g 1, un- der E 1 over I 2, and again over c, passing from the top of n 1 to I 4 ; and by this means, if one end of the back of goods marked k, and placed upon the frame f., {fig. 61,) is fastened to the end of the guide cord, the goods will, when the calender is put in motion, be conducted and washed thirty times through the water in the cisterns, and squeezed thirty times through the calenders. As the operation proceeds and the guide cord passes through the calender, it is wound by hand upon roller a to prevent it from becoming entangled, and to keep it in readiness for the next operation. As soon as the first end of the goods has passed through fig. 61, and arrives at the guide roller i 4, it is detached from the end of the guide cord and attached to the guide cord to the other end, or with the opposite set of calenders. After this, by putting these in motion, the goods are washed and squeezed through its cisterns, which cisterns are supplied with hot and strong lime lye, and the goods passing over guide roller i 9, they are conveyed over other guide rollers to be placed for the purpose, and taken down by some person or some proper machinery into one of the boiling vessels, where, steam or fire heat being added, they are suffered to remain while the lime-boiling takes effect. We need not follow the inventor into all the particulars. When the goods were suffi- ciently acted on by one solution, another solution was used, so that this mode of calender- ing not only was a method of moving the goods from place to place by means of rollers, but it was a method also of saturating goods thoroughly with a solution, and of wasliing them. . It was by a similar method that Mr. Bcntley bleached skeins of yarn, of linen, or of cot- ton. The skeins are looped together by tying any soft material round the middle of the first skein, which will leave the loops from one end of the next skein to pass half-way through, and which will always leave other two loops, and by repeating which any quantity of skeins may be looped together, tying the last loop with another soft material. The mode of saturating the goods with solutions is effected by the arrangement shown in fig. 02 process. Rapid motion and frequent pressure are introduced instead of a still soaking BLEACHING. 62 155 \zr -K^T c/tK>K^1K^^.^>tt^-^/^Hs^^c_. Vyiglll4U.U- .ll j!}i .i!!P!'!| ^u^u. W^ A is a roller for the guide cords ; b, e, b, are eleven washing rollers ; c, c, c, are speed rollers ; e, e, e, are twelve rollers immersed in twelve divisions of the cistern G. The eleven staple-formed irons which pass through the frame rails on each side of the centres of the eleven rollers b, b, b, and the eleven rollers c, c, c, serve to stay these rollers in their places, at the same time allowing the eleven washing rollers b, b, b, to rise and fall accord- ing to the pressure by which they are held down, by the eleven weights attached to these irons at h, and upon the bottom rail may be placed such staves, brushes, or rollers, as may be found necessary for holding and brushing the goods in the best manner to keep them straight during the different washings in water and bleaching liquors. The goods are pre- pared by steeping, as before described, and placed in batches at f, and passing under the immersing rollers e and the twelve divisions of cistern g, between the eleven speed rollers c and the eleven washing rollers b, as seen at k, are taken down straight and open into one of the vessels, and are then boiled by steam, which is succeeded by repeated washings alter- nately in water and bleaching liquors, until they are sufficiently bleached, as before de- scribed. The elevation and ground plan of a bleach-house and machinery capable of bleaching 800 pieces of 4 lbs. cloth per day, (for best madder work,) with the labor of one man and three boys, Avorking from 6 until 4 o'clock, exclusive of singeing and drying, arc represented in figs. 63 and 64, (p. 156.) The letter d represents two lengths of cloth of 400 pieces each, (end of pieces being stitched together by patent sewing machine made by Mather and Piatt,) making together 800 pieces, passing through washing machine g, and from thence delivered over winch, u\ 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, ff, washed, and passed into second kier, b, (operation occupying one hour,) where they arc boiled for twelve hours in ashes and resin ; again withdrawn by the same machine, r/, 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, h, and threaded through sour-machine, e, soured, passed over winch, e", and piled at k\ (operation, one hour,) where it remains in the pile for three hours. It is then squeezed at c, and washed through machine, (f, (an hour's operation,) delivered into third kier, «, boiled for six hours, washed at ff, squeezed at u, (an hour's operation,) and passed through chcmick machine, (an hour'.s operation,) and piled for one hour ; after which it is soured again, (an hour's operation,) sciucezed, and washed at rj, (an hour's operation,) squeezed again at/, (an hour's operation,) and dried by machine at p, {jiff. 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 prc]iarc the pieces for the sour and chemick machines: Secondly, A drier state of the cloth than cnii possibly be produced by the washing machine alone, thus fitting it to become better satu- rated with the chemick or sour : Thirdly, Tlie piece passing from the souring to the washing machine, in tins 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 macliines is nnieh higher than usual, experience having shown that the various operations are thus better performed 156 BLEACHING. 6S ■■"'///////M/yy-'^- C4 CZJ S({UECZERS 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, tlie plan of proceeding at Messrs. McXaughten, Barton, and Thorn'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 30i) 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 crver 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 ia?comnicnded to be made of strong boiler-plate iron.) One of these is shown in section, a and b are the kiers ; c is a perforated platform, on which the goods to be bowked are laid ; k k is the pijic connecting the bottom of the kier h with the top of the adjoining kier, a ; and /, /, the corresponding pipe coimecting the opp(jsite ends of the kiers a and h ; vi in are draw-olf cocks, connected with the pipes k and /, l)y*which the kiers can be emi)ticd of spent liquor, water, &c. ; n and o are ordinary two-way taps, I)y which the steam is admitted into tlie respective kiers from the main pijjc, ;>, and the reversing of which shuts off tlie steam com- munication, and admits the bowking \u\\n)v .as it becomes expelled from the adjoining kier ; , sulphur 33'0. Blende occurs either in a botryoidal form or in crystals, (often of very com- plex forms,) belonging to the tctrahedal 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 horse." 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 Yieille Montagne 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 EngHsh 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 : — Sulptur. Zinc. Iron. Cadmium. Carinthia New Hampshire New Jersey - - - Tuscany 32-10 32- 6 32-22 82-12 64-22 52-00 67-46 48-11 1-32 10-0 11-44 trace 3-2 trace 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 2J 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 possit)le, continued to increase the size of the block, so that, although ^^ 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 2i» 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 dnuned 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 6G 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 hwmatite 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-buttons. 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, a, which are made separately, and accurately ground into it, so that they may be put together, or taken apart at pleasure. The point 6 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-})iece is pressed against the lips, oi-, 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 imbroken 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 check muscles. Some years since, Mr. John Prideaux, of Plymouth, printed some valuable " Sugges- tions" for the use of the blowpipe by working miners. Sonic 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 metalhirgic assays, the common blowpipe does very well. A mere taper- ing tube, 10 inches long, i inch (liameter at one end, and the ojiening at the other scarcely e(iual to admit a pin of the smallest kind, the smaller end curved oft" for 1 .J- inch to a right angle. A bulb at the bend, to contain the vapor condensed from the breath, is u.seful in long operations, but may generally be dispensed with. In selecting the blowpipe, the small 16i 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 pii)e-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 fire, 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. 67), 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 Vio 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 fi ~ -^ 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, {Jig. 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 l__^ sharp end may serve as a pivot, descending about ^ inch below ^ — -— -.____^ the centre, taking care that the ends of the needle fall enough ' — [!ivi-^\ below the pivot, to prevent it overturning. It must be mag- 'v:;;'! netized, by sliding one end of a magnet half a dozen or more >■■'" J 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 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, oe BLUE STOKE. 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, g 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 scissors, and iaid in the trough, with the line 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 6erto?-needles are the finest,) and passed through a slip of cork the width of the centre of the trough, about \ inch square, •J- 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 ^ 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 scjuare 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, \ 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 Tor 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 he 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 common air is admitted through tlic other trunnion, which is also hollow, and is discharged in the centre of the hydrogen through a central conical tube ; the magnitude and intensity of the fiame 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- apffcl. ' BLUE COPPERAS, or BLUE STONE. The commercial or common names of the sulphate of copper. See Copper. 166 BLUE YITEIOL. BLUE VITRIOL. Sulphate of copper. When found in nature, it 13 due entirely to the decomposition of the sulphides of copper, especially of the yellow copper pyrites, which are Uable to this change when placed under the influence of moist air, or of water contain- ing air. BOGHEAD COAL, and other JBrown 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 arc found at Boghead, near Bathgate ; Eocksoles, 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 Sicjillaria, and its roots, (Stipnarias,) 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, 1"200. According to Dr. Stenhouse, F. R. S., its composition is: — Carbon 65-72 Hydrogen 9-03 Nitrogen 0'72 Oxvgen- -- 4-78 Ash 19-75 100-00 Dr. Stenhouse's analysis of the ash of Boghead coal, from three analyses, was as fol- lows : — Silica 58-31 Alumina .-..-...-.. 33-65 Sesquioxide of iron -- 7-00 Potash 0-84 Soda 0-41 Lime and sulphuric acid traces. Dr. Andrew Fyfc, F. R. S. E., on analysis, found that the coal yielded, from a picked specimen, 70 per cent, of volatile matter, and 3n per cent, of coke and ash. From a ton he obtained 14-880 cubic feet of gas, the illuminating power of which was determined Ijy the use of the Bunsen photometer, the gas being consumed by argands burning from 2A to Si 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. Q^«„;fi» Condensation Specific ^ Chlorine Gravity. 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 i" 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 Torbanc, Inchcrnss, 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 10i»,000 tons per annum, it cannot last many years. BOG IKON ORE. 167 The following section of a pit at Torbane shows that the cannel occurs in ordinary coal measures, and under circumstances common to beds of coal : — Ft. In. Boghead house coal --2 7 Arenaceous shale 6 Slaty sandstone 07 Shale and ironstone, containing remains of plants and shells - 10 Cement stone (impure ironstone) 4 Boghead cannel 19 Fire clay, full of Stigmarice -------05 Coal (common) 06 Black shale Of Coal 1 Shale - - - Of Coal 0^ Fire clay H Hard shale 03 Thin laminae of coal and shale -• 3^ Common coal ...--.--.-0 6 Fire clay 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 ai'e 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 Ca'amites ; and the ironstone nodules, fossil shells of the genus Vnio. The floor of the mine contains Stiginarke ; and the coal itself affords more upright stems of Siyillarice, and its roots {StigmaricB) 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 alteration. — E. W. B. BOGHEAD NAPHTHA, {syu. Bathgate naphtha,) naphtha from the Boghead coal. See Naphth.vJ Booiiead. 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 168 BOILER. 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. Bo" 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 Ii;on. 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 bole is of a bright red color. This is frequently employed as a dentifrice, and in some cases it is administered medicinally. Bole of Bloia is yellow, contains carbonate of lime, and effervesces with acids. Bo/iemiau bole is a yellowish red. French bole is of a pale red, with frequent streaks of yellow. Lemnian bole and Siliscan bole are, in most respects, similar to the above-named va- rieties. The following analysis are by C. Van Haucr: — 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 Mar/azine. 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., docs 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-bons 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-l)on, forming a crust inclosing the syrup, which constantly gives up sugar to the crystallizing crust until it becomes sufilciently 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. Fainted 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 uuder the " Prefet de Police," as to the colors which may be employed in confectionary. These are to the following efi'ect :— " 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, Sulphide of arsenic, Acetate of copper. Oxide of lead, Chromate 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, according to the formula 3R0, P0^ Bone phosphate of lime was considered by Berzelius to be 8Ca0, 3P0'. 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 57 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 SchlossberTcr 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 bone's, 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 had 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 Ox bones. Fossil bones. Carbon .... 5o-4()i .... 50-130 Hydrogen - - - - 7-111 - - - - 7-073 Nitrogen .... 18-154 .... 18-449 Oxygen .... 24119 .... 24-348 Sulphur .... 0-216 This is the same composition as that of the gelatinous tissues. 170 BONES. 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 flxt skinmied oft' and sold to the candle makers, and the size afterwards boiled down in an- other vessel till it is of sufficient strength for stiffening tlie 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 - - - 20 2-1 Berzelius. Marchand. 2-0 Berzelius. Human bones - - ■ 1-8 to 2-3 ) 2-0 in mean C 1-6 to 2-2 1 Frerichs. 1-9 in mean |- 2-3 to 2-0 ) Yon Biria. Bird bones 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 arc 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 pohshed with whitening and water. noltzapfTcl also informs us, that after the turning tool, or scraper, has been used, bono 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 ; 4tli, a small quantity of white wax is rubljcd on the work with a (juick 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 an■ Hydrochloric and hydrosulphuric acid ) - 74 to 84 - 14 to 8 - 2-5 to 1-25 - 7 to 5-75 - 2-5 to 1 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 sufficient 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. — JBischof. In 1855 our Imports were : — Cwts. Computed real Value. Boracic acid from Sardinia - - 85 - - - £383 " " Tuscany - 26,777 - - - 121,163 " " Gibraltar - - 947 - - - 4,285 And in 1856 :— 27,809 £125,831 Boracic acid from Sardinia - Cwts. - 313 - Computed re.il Value. - £1,377 " " Tuscany - " Peru " " other parts 25,003 - - 1,453 - 1 - - 110,264 6,394 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 Octahedral Borax — 1 equivalent of boracic acid 1 " soda - 5 " water Prismatic Borax — 1 equivalent of boracic acid 1 " soda - 10 " water 1262 for 100-0 872 or 47-7 390 " 21-3 662-5 for 31-0 1824-5 100-0 872 or 36-55 390 (1 16-35 1-125 (1 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 liolos thus made were again tilled. 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 Ruisscau 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 52° 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 hydi-ochloric 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 00245 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 43-50, soda 19-25, and water 37-19. Lagotiite 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 inliabited those now deserted regions. In the "Guide du Sorideur," by Jl. J. Degousec, we find it stated, with reference to China, "There exists in the canton of Ou-Tong-Kiao many tliousand wells in a space often leagues long by five broad. These wells cost a thousand and some hundred taels, (the taiil being of the value of Cs. &d.,) and are from 1,500 to 1,800 feet deep, and about 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 tlie 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 arc 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 ai'e 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. Sucii 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 s. d. 5 6 per fathom. 11 16 6 " 22 176 BOEING. cicnt 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 workman alternately allowing the rods to be drawn up a certain distance, and then, by rela.xing his hold, allowing them to fall. — — Swindell, on Boring, Tlie 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 : — First 5 fathoms . - - . Second 5 " .... Third 5 " - - . . Fourth 5 " .... and so increasing 5s. Cd. 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. Second 5 " 15 " Third 5 " 22 6 " Fourth 5 " SO " and so increasing 7s. &d. 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 : — First 20 yards - . - Next 10 " " 10 " " 10 " " 10 " and so advancing Is. Gd. 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 : — First 20 yards Next 10 " " 10 " " 10 " " 10 " 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 tackUng, In Scotland the general prices for boring are as follows : — s. d. First 5 fathoms 5 per fathom Second 5 " 10 " Third 5 " 15 " Fourth 5 " 20 " 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 .... Second 5 " .... Third 5 " .... 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. s. d. 3 5 6 per yard 6 6 8 9 6 s. d. 3 6 per yard 4 6 5 6 " 6 6 1 6 10 per fathom. 20 u SO (( BRASS. irr 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 apphed sufficient to melt the latter, and the mixture of the two substances is eflfected 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, 11 "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. ; Buchsbawn, Germ. ;) Buxus scmpervirens.—liwo 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 latlie-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 1^ to 2 inches. — Holt~apffel. 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 emptoyed by the wood engraver. See Engraving on Wood. A similar wood was imported from America by the name of Tiigmutton, 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 rcverberatory 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 rcverberatory furnace till they are thoroughly calcined, when the substance becomes pulverulent, and assumes a red color. It is then ready for immediate use. Mr. Holtzapff'el, in liis " Mechanical Manipulation," has given some very important descriptions of alloys. From his long experience in manufacture, no one was more capable than Mr. Iloltzapffel 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 aljout 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 1 of copper, the mixture has the brilli;mt silvery color of speculum metal, but with a bluish tint. These alloys — from about 8 to 1(5 ounces to the pound of copper — are extensively used Vol. in.— 12 178 BRASS. a to '' o £^ ^« E ° to c ]3 • ^ -^ ^ a t- *^ ... C" a " rrt e * S S ct S T S s S a; - "§ -2 ^ -B s 3 "3 o C-X X! 2 P3 ft « ^2; ca S c o k i •" >> o aj o «J ; >.% "S .t; 3 '2 I ^ t- .ti .c .— .t: G^ r: t- »^^ t- t- lO'^COffl^^OCSOOt- ooo«;>o>ooioo>0'i-Ht-0 eOi-ic 'O — HP'S ki ,-. ,-s ^ _^ o o ^ s I-H d l-H C<| ,-1 CO p ^ O O CO OO O ^ ^ O^ w- ^.^ w.^ i*.^ -. <•■. OOOOOOODOOOOOOOOOO ooocoi—cociccooi^coctr-iinio C](M(>4C^J:-OOCOCOOTti'^COOOO a to Ccooocooovoc-iir-oioeciocoocjoootCr-^c^go C3C.^i?l-^-ioiOODMC:c/-aOC5Ci-HS'JCC;«fOOCOO -F-H-H- +-H-4-f -f-+-H-H-f- 4-+++ • • + OC'iOOCO-ocr5coc»Ot-in''Mc:t-0Ot-000>q'HClC<5-Hin r— ( r— < f-H »— < I-H f— I .— I i—t I— < I— * C^ C-1 01 d CI Ol 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 1^ 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. IOV5 oz. Muntz's metal, or 40 zinc and 60 copper. " Any proportion," says the patentee, " between the extremes, 50 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 ('/is 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. BRASSIXG 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-Met.\li.urgy. BRAZIL WOOD. The ibiripitanr/a, 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 nianiior in which it has been cut down by the Government agents, without any regard l)fing jiaid 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 brasas, a glowing fire or coal ; its botanical name is Cmsalpinin Brnsileto. The leaves are pinnated, the flower white and papilionaceous, growing in a pyramidal epikc; 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 Brasileto, 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 bein"' 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 tvood 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 Sa7ita 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 Diieing. 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 imtritive 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, but 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 bU ronye glace d^-Utvcrcfne, which contains hardly 45 per cent, of starch, and as much as 86 per cent, of gluten, though admirably adapted for the nianufacture of macaroni, vermicelli, semolina, and other pates d'ltalie, 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. Daugiish'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, kneadiiig, and fennentiiiri. When the baker intends to make a batch of bread, his first care is, in technical lan- guage, to stir a fcrmpiit. This is done, in London, by boihng a few potatoes, in the pro- portion of 5 lbs. or G 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 3 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 inipnrt a proper temperature (from 70' to 90° F.) to the liquid mass, which sliould 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 fermentjition 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 ))e 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 after 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 wliich 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 throuo'h, and the sponge collapses or drops down. This is called the Jirst 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 tiie 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 full" 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;V 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 bind 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 '■'■proofed" it is weighed oft" 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 micro.scope, 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 BREAD. good for a few weeks, if kept in a cool place. When in good condition, it is an escellent 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 yeast" 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 yeast, and is nothing more than a decoction of hops to which malt is added while in a scalding hot state ; wlien the licjuor 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 panilieation is not dithcult 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 y}• 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 190 BREAD. 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 11 ^7 ^v- rusty, and spoil the color of the broad. Bread-baking may be considered as consisting of four operations — namely, heating the oven, putting the dough into the oven, baking, and BREAD. 82 83 - -, 84 191 192 BREAD. taking the loaves out of the oven. The general directions given by M. RoUand for each of these operations are as follows : — In order to obtain a proper heat, and one that may be Qasily managed, it is necessary to charge the furnace moderately and often, and to keep it in a uniform state. When the fire is kindled, tlie 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, on 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. Sweeping between the floors should ])c performed about every fortnight. In case of accident or injury to the thermometers, the following directions, which, in- deed, apply to all ovens, may enalile 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 RoUand's oven takes place at a temperature varying from 410° to 432° F., 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-water oven, two cstabhshments-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 10 per cent., the ashes ranging from 0-5 to l-'J per cent. This day, (17th of March, 185S,) 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. 6ld. per week, which sum, divided by 12, would give 3s. O^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 84 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 fiiir 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 50 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 reHed upon. 70 sacks of flour manufactured into genuine bread, in the ordinary way, would yield 0,300 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 : — £y the Ordinary Process. RETURNS. £ .■!. d. 6,300 loaves (4 lbs.) at 7(?. 183 15 * It is absolutely necessary thus to establisli a dislinction bctwocn four-pounds and qu.artcrn loaves, because the latter very seldom indeed have that weight, and this deficiency is, in fact, one of the ])rofits calculated upon; for, although the Act of rarliament (Will. IV^ cap. xxxvii.) is very strict, and dii-ects (sect, vii.) that bakers dcliveiinf; breail by cart or carriage Khali bo provided with scales, weights, Ac, for weighing bread, this rrqui.silion is schfoni, if ever, complied with. , There arc, of course, a few bakers whoso quartern loaves weigh exactly four pounds, but the immenso majority are from four to six ounces short. Vol. III.— 13 lU BREAD. EXPENSES. £ S. d. 70 sacks of household flour at 37s. 129 10 Coals, gas, potatoes, yeast, salt, wages, and other baking ex- penses, at 6s. per sack 17 10 Rent, taxes, interest of capital, and general expenses - - 24 10 171 10 Net profit on 1 week's baking £12 50 Si/ J^erkitis's Process. 6,300 loaves (4 lbs.) at 7c?. £ s. d. - • 183 15 £ s. d. 129 10 3 10 1 15 1 7 1 t) 16 4 24 10 — 162 12 70 sacks of flour at 37s. Yeast, potatoes, and salt, at l.s\ per sack .... Coals at (>d. 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 £21 13 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 4M per sack, which, for 70 sacks, is £1 6s. St?., 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 167° F., 1,000 grains of "bread (or flour) with 1,000 grains of bruised barley malt, in 5,000 grains, or in a little more than half a pint, of water. AVhen 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 70 per cent, of the most nutritious part of the flour, a loss which, for London only, is equal to at least 7,500 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, aflfect 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 farthtr 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, 52 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 Va- 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 i.n 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 S}'mpathies 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 twopences ; 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 will 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 giceii weight of wheat contains more nutriment than the flopr obtained from that weight of tvhcat. The inquiry of the Committee of the House of Commons, and the defence of white bread versfus 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 - • 52-0 Gluten 14-9 Sugar 1-0 Fatty matter 3*6 Woody " 9-7 Salts 6-0 Water 138 100 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 190 BREAD. in tlie 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 CO lbs. produces, according to the mode of manufacturing flour for London, 4Y lbs. — that is, '78 per cent, of flour, the rest being bran and pollards ; if we deduct 2 per cent, of woody matter, and 1 ^ per cent, for waste in grinding at the mill, the bushel of (30 lbs. of wheat would yield 58 lbs., or at least 96f 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 Royal Institute ncaily four years ago, M. Mfege Mouri6s announced that he had found under the envelope of the grain, iu 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 cercalin ; 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. 51. 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 the 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. Mfege Mouries, has two very distinct properties :— the first consists in converting the hydrated starch into glucose and dextrine ; the second, which is much more important 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, yicldipg 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 descril>cd 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 with 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 disseminateil by the millstone into the inferior products of corn. " 3dly. The employing that part of corn producing browni lircad 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 lirown 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. " Sthly. 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. " Gthly. The application of corn washed or strii)ped 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 Ijread. " Sthly. 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. ^Vhen floxur 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 touniesol. 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 suSicieutly prove it, thus divesting such an application of its industrial appropriation. " Second Instance. \V/ie7i raw four 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 tlie fragments of ))ran, 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 arc extracled, 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 supei'ior 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 8G^ F., after being suitably separated by means of some inert dust, and pre- vious to being made use of, it should lie dipped into 10 parts of water, lightly sweetened, for 8 to 10 hours, a fit time for the li((uid being brought into a full fermentation, at which time the yeast has recovered its former power. The same process will hold good for manu- ticturing rye bread, only 25 per cent., about, of course bran are to be extracted. For manufacturing l)iscuits, 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 sui)crior to the common biscuits, both for their good taste and preservation. Should, however, an old practice exchide all manner of fermentation, then I might dilute the rougii parts of flour in either acidulated or iu)n-acidulated wafer, there to l)e left to work for the same time as l)c- 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 BEEAD. 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 li(iuid 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 : " Fig. 87 is a longitudinal section, znAfirf. 88 an end view, of the machine from which the bran is ejected. The apparatus rests upon a cast-iron framing, «, consisting of two cheeks, kept suitably apart l)y tie pieces, b ; a strong cross-b.ar 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, ti .c « 1 u ' a s XInsh, "2 *o Hcnt c Mnsh, ••5 o Hest of Jlash, •a o Heat of Mash, -^ = 146° to a 14.5° to 147°. £ 144° to 146°. § £ 143° to 145°. 5 £ 148°. Oi ' 1 in S 02 g i" f> FirkiDS E ' s 1 Fitkins 8 Firkins 1 E 9 Firkins 10 Firkins 1 11 Firkins 12 Firkins 1 1 H- per Qr. H H per Qr. per Qr. P t- per Qr. per Qr t- per Qr. per Qr. P ll--:,l, H. M. Fah. H; M. Fnh. H. M. Fah. H. M i 10" 197-00 4-00 ' 10° 1S9-00 184-00 300 10° 178-00 175 00 2-00 10° 172-00 170-00 1-00 1 15 195-17 4-00 ; 15 1S7-42 182 59 3-00 15 176-84 173 92 2-00 15 171-00 169-19 1-00 ?n 193-34 4.00 20 1S5-84 181-18 3 00 20 175-68 172-84 2-UO 20 17000 168-28 1-00 '>'. 191-51 400 25 1S4-26 179-77 J3-00 25 174-52 171-70 2 00 25 1G9-00 167-37 1-00 1 so 1S9-6S 4-00 ' 30 1S2-6S 178 3G 13-00 30 173-36 170-G8 2-(!0 30 IGS-CO 166-46 1-00] .So 1S7-85 4 00 i 35 lSO-10 176-95 ■3 00 35 172-20 109 60 2-00 35 167-00 165 55 1-00 40 1SG03 4-00 1 40 179-52 175-54 300 40 171-04 108-52 2-00 40 166 00 164-64 1-00 45 1S4-19 4 00 45 177-94 174-13 3 00 45 169-88 1G7 44 2 00 45 165-00 163-78 1-00 O'l lS-2-36 4-00 ! 50 176-3C 172-72 3-00 50 16S-72 1G6 8G 2-00 50 164-00 102-82 100 1 .')5 ISO -53 400 I 55 174-73 171-81 3 00 55 107 56 165-28 2-00 55 163-00 161 91 1-00 ' 1 CO 17S-70 3 40 ! fio 173-20 169-90 2-45 60 166-40 164-20 1-50 60 16200 161-00 0-55 i r>5 17GS7 3-20 fi5 171-62 168-49 2 -.30 65 165-24 163-12 1-40 65 161-00 160-19 0-50 70 17504 3-00 70 170-04 167 07 2-15 70 164-08 162-04 1-30 70 16000 159-28 0-45 1 tipn t of the Tap, ' Heat of the Tap, Ilcat of the Tap, Heat of the Tap, 1 1 14° to 146°. 143° to 145'. 1 142° to 144.° 141° t{ )143°. The following example will give an idea of the proportions for an ordinary quality of beer : — Suppose 13 imperial quarters of the best pale malt be taken to make 1,500 gallons of beer, the waste may be calculated at near 900 gallons, or 2,400 gallons of water will be re- quired in ma.shing. As soon as the water in the copper has attained the heat of 14.'° in summer, or 1G7° in winter, 600 g.allons of it are to be run of! into the mash-tuh, (which has {)reviously been well cleansed or scalded out w-ith 1 Killing water.") and the malt gradually liut rapidly thrown in and well intermixed, so that it may be uniformly moistened, and that no lumps remain. After continuing the agitation for about half an hour, more lirpior, to the amount of 450 gallons, at a temperature of 190°, may be carefully and gradually introduced; (it is an ad- vantage if this can be done by a pipe inserted under the false Iiottom of the mash-tub,) the agitation lieing continued till the whole assumes an equally fluid state, taking care also to allow as small a loss of temperature as possible during the operation, the resulting- temper- ature of the mass being not less than 143°, or more than 148 . BREZILIN" AND BEEZILEIN. 205 The mash is then covered close, and allowed to remain at rest for an hour, or an hour and a half, after whicli the tap of the mash-tub is gradually opened, and if the wort that first flows is turbid, it should be carefully returned into the tun until it runs perfectly limpid and clear. The amount of this first wort will be about 675 gallons. Seven hundred and fifty gallons of water, at a temperature from 180' to 185°, may now be introduced, and the raasliing operation repeated and continued until the mass becomes uniformly fluid as before, the temperature being from lUif to 170'. It is then again covered and allowed to rest for an hour, and the wort of the first mash having been quickly transferred from the underback to the copper, and brought to a state of ebullition, the wort of the second mash is drawn off with similar precaution, and added to it. A third quantity of water, about COO gallons, at a temperature of 185^ or 190^, should now be run through the goods in the mash-tun by the sparging process, or any means that will allow the hot liquor to percolate through the grains, displacing and carrying down the heavier and more valuable products of the first two mashings. The wort is now boiled with the hops from one to two hours. The object of boiling the wort is not merely evaporation and concentration, but extrac- tion, coagulation, and, finally, combination with the hops ; purposes which are better accom- plished in a deep confined copper, by a moderate heat, than in an open, shallow pan, with a quick fire. The copper, being encased above in brickwork, retains its digesting tempera- ture much longer than the pan could do. The waste steam of the close kettle, moreover, can be economically employed in communicating heat to water or weak worts ; whereas the exhalations from an open pan would prove a nuisance, and would need to be carried oft" by a hood. The boiling has a four-fold effect: 1, it concentrates the wort; 2, during the earlier stages of heating, it converts the starch into sugar, dextrine, and gum, by means of the diastase ; 3, it extracts the substance of the hops diffused through the wort ; 4, it co- agulates tlie albuminous matter present in the grain, or precipitates it by means of the tannin of the hops. The degree of evaporation is regulated by the nature of the wort and the quality of the beer. Strong ale and stout, for keeping, require more boiling than ordinary porter or table-beer, brewed for immediate use. The proportion of the water carried oft' by evapora- tion is usually from a seventh to a sixth of the volume. The hops are introduced at the commencement of the process. They serve to give the beer not only a bitter aromatic taste, but also a keeping quality, or they counteract its natural tendency to become sour — an effect partly due to the precipitation of the albumen and starch, by their resinous and tanning constituents, and partly to the antifermentable properties of their lupuline, bitter l)rinciple, ethereous oil, and resin. In these respects, there is none of the bitter plants which can be substituted for hops with advantage. For strong beer, powerful fresh hops should be selected ; for weaker beer, an older and weaker article will suffice. The stronger the hops are, the longer time they require for extraction of their virtues ; for strong hops, an hour and a half or two hours' boiling may be proper ; for a weaker sort, half an hour or an hour may be sufficient ; but it is never advisable to push this process too far, lest a disagreeable bitterness, without aroma, be imparted to the beer. In some brew- eries, it is the practice to boil the hops with a part of the wort, and to filter the decoction through a drainer, called the jack hop-back. The proportion of hops to malt is very various ; but, in general, from IJ lbs. to li lbs. of the former are taken for 100 lbs. of the latter in making good table beer. For porter and strong ale, 2 lbs. of hops are used, or even more ; for instance, from 2 lbs. to 2i lbs. of hops to a bushel of malt, if the beer be destined for the consumption of India. During the boiling of the two ingredients, much coagulated albuminous matter in various states of combination, makes its appearance in the liquid, constituting what is called the breaking or curdling/ of the wort, when numerous minute flocks are seen floating in it. The resinous, bitter, and oily-ethereous principles of the hops combine with the sugar and gum, or dextrine of the wort ; but for this eftect they require time and heat ; showing that the boil is not a process of mere evaporation, but one of chemical reaction. A yellowish- green pellicle of hop-oil and resin appears upon the surface of the boiling wort, in a some- what frothy form : when this disappears, the boiling is presumed to be completed, and the beer is strained oft" into the cooler. The residuary hops may be pressed and used for an in- ferior quality of beer; or they may be boiled with fresh wort, and be added to the next brewing charge.' After l)eing strained from the hops, by passing through the false l)()ttom of the hop- jack, and allowed to rest on the coolers a sufficient time to deposit the greatest jjortion of the flocks separated in the boiling, the cooling process is rapidly completed by the action of the Jiefrifierator. See RKFuniEUATioN of Wouts, vol. ii. The wort is then ready for the inoculation of the yeast and the commencement of the fermentative process, which completes the finished beer. Sec the articles Beku and Fici;- MKNTATION. R. W. II. BREZILIN and I3REZILEIX. According to M. Preisser, the coloring matter of Brazil wood {Brczilin) is an oxide of a base Brezilein, which has no color. 206 BlilOK. BRICK. (Brique, Fr. ; JSacksteine, Ziegelsteine, Germ.) A solid rectangular mass of baked clay, employed for building purposes. The natural mixture of clay and sand, called loam, as well as marl, -which consists of lime and clay with little or no sand, are the materials usually employed in the manufacture of bricks. There are few places in this country which do not possess alumina in combination with silica and other earthy matters, forming a clay from which bricks can be manufactured. That most generally worked is found on or near the surface in a plastic state. Others are hard marls on the coal measure, new red sandstone, and blue lias formations. It is from these marls that the blue bricks of Staffordshire and the fire-bricks of Stourbridge are made. Marl ha.s a greater resemblance to stone and rock, and varies much in color ; blue, red, yellow, kc. From the greatly different and varying character of the raw material, there is an equal difference in the principle of preparation for making it into brick ; while one merely requires to be turned over by hand, and to have sufficient water worked in to make it subservient to manual labor, the fire-clays and marls must be ground down to dust, and worked by powerful machinery, before they can be brought into even a plastic state. Now these various clays also shrink in drying and burning from 1 to 15 per cent., or more. This contraction varies in proportion to the excess of alumina over silica, but by adding sand, loam, or chalk, or (as is done by the London brick-makers) by using ashes or breeze — as it is technically called — this can be corrected. All clays burning red contain oxides of iron, and those having from 8 to 10 per cent., burn of a blue, or almost a black color. The bricks are exposed in the kilns to great heat, and when the body is a fire-clay, the iron, melting at a lower temperature than is sufficient to destroy the bricks, gives the outer sur- face of them a complete metallic coating. Bricks of this description are common in Staf- fordshire, and when made with good machinery, (that is, the clay being very finely ground,) are superior to any in the kingdom, particularly for docks, canal or river locks, railway- bridges, and viaducts. In Wolverhampton, Dudley, and many other towns, these blue bricks are commonly employed for paving purposes. Other clays contain lime, and no iron ; these burn white, and take less heat than any other to burn hard enough for the use of the builder, the lime acting as a flux on the silica. Many clays contain iron and lime, with the lime in excess, when the bricks are of a light dun color, or white, in proportion to the quantity of that earth present ; if magnesia, they have a brown color. If iron is in excess, they burn from a pale red to the color of cast-iron, in i^roportion to the quantity of metal. There are three classes of brick earths: — 1st. Plastic clay, composed of alumina and silica, in different proportions, and contain- ing a small percentage of other salts, as of iron, lime, soda, and magnesia. 2d. Loams, or sandy clays. 8d. Marls, of which there are also three kinds ; clayey, sandy, and calcareous, according to the proportions of the earth of which they are composed, viz., alumina, silica, and lime. Ahmiina is the oxide of the metal aluminium, and it is this substance which gives tenac- ity or plasticity to the clay-earth, having a strong affinity for water. It is owing to excess of alumina that many clays contract tfto much in drying, and often crack on exposure to wind or sun. By the addition of sand, this clay would make a better article than we often see produced from it. Clays contain magnesia and other earthy matters, but these vary with the stratum or rock from which they are composed. It would be impossible to give the composition of these earths correctly, for none are exactly similar ; but the follow- ing will give an idea of the proportions of the ingredients of a good brick earth : silica, throe-fifths ; alumina, one-fifth ; iron, lime, magnesia, manganese, soda, and potash forming the other one-fifth. The clay, when first raised from the mine or bed, is, in very rare instances, in a state to allow of its being at once tempered and moulded. The material from which fire-bricks are manufactured has the appearance of ironstone and blue lias limestone, and some of it is re- markably hard, so that in this and many other instances, in order to manufacture a good article, it is necessary to grind this material down into particles as fine as possible. Large quantities of bricks are made from the surfiice marls of the new red sandstone and l)lue lias formations. These also require thorough grinding, but from their softer nature it can l»e effected by less powerful machinery. — Chamberlain. Recently, some very valuable fire-bricks have been made from the refuse of the China Clay Works, of Devonshire. The quartz and mica left after the Kaolin has been washed out, are united with a small portion of inferior clay, and made into bricks. These are found to resist heat well, and are largely employed in the construction of metallurgical works. See Clay. The principal machines which have })een worked in brick-making are three — 1st, the pug-mill ; 2d, the wash-mill ; 3d, the rolling-mill. The pug-mill is a cylinder, sometimes conical, generally worked in a vertical position, with the large end up. Down the centre of this is a strong revolving vertical shaft, on which are hung horizontal knives, inclined at such an angle as to form portions of a screw, BKICK. 2or that is, the knives follow each other at an angle forming a scries of coils round this shaft. The bottom knives are larger, and vary in form, to throw off the clay, in some mills verti- cally, in others horizontally. Some have on the bottom of the shaft one coil of a screw, which throws the clay off more powerfully where it is wished to give pressure. The action of this mill is to cut the clay with the knives during their revolution, and so work and mix it, that on its escape it may be one homogeneous mass, without any lumps of hard untempered clay ; the clay being thoroughly amalgamated, and in the toughest state in which it can be got by tempering. This mill is an excellent contrivance for the purpose of working the clay, in combination with rollers ; but if only one mill is worked, it is not generally adopted, for, although it tempers, mixes, and toughens, it does not extract stones, crush up hard substances, or free the clay from all matters injurious to the quality of the ware when ready for market. This mill can be worked by either steam, water, or horse power ; but it takes much power in proportion to the quantity of work which it performs. If a brick is made with clay that has passed the pug-mill, and contains stones, or marl not acted on by weather, or lime-shells, (a material very common in clays,) or any other extra- neous matter injurious to the brick, it is apparent from the action of this mill that it is not removed or reduced. The result is this : the bricks being, when moulded, in a very soft state of tempered material, or mud, considerably contract in drying, but the stones or hard substances not contracting, cause the clay to crack ; and even if they should not be suffi- ciently large to do this in drying, during the firing of the bricks there is a still further con- traction of the clay, and an expansion of the stone, from the heat to which it is subjected, and the result is generally a faulty or broken brick, and, on being drawn from the kilns, the bricks are found to be imperfect. The earth, being sufficiently kneaded, is brought to the bench of the moulder, who works the clay into a mould made of wood or iron, and strikes off the superfluous matter. The bricks are next delivered from the mould, and ranged on the ground ; and when they have acquired sufficient firmness to bear handling, they are dressed with a knife, and staked or built up in long dwarf walls, thatched over, and left to dry. An able workman will make, by hand, 5,000 bricks in a day. The different kinds of bricks made in England are principally ^/ac^* brickx^ graij and red stocks, marl faciwj bricks, and cutting bricks. The place bricks and stocks are used in common walling. The marls are made in the neighborhood of London, and used in the outside of buildings ; they are very beautiful bricks, of a fine yellow color, hard, and well burnt, and, in every respect, superior to the stocks. The finest kind of marl and red bricks, called cutting bricks, are used in the arches over windows and doors, being rubbed to a centre, and gauged to a height. Bricks, in this country, are generally baked either in a clamp or in a kiln. The latter is the preferable method, as less waste arises, less fuel is consumed, and the bricks are sooner burnt. The kiln is usually 13 feet long, by 10^ feet wide, and about 12 feet in height. The walls are one foot two inches thick, carried up a little out of the perpendicular, inclined towards each other at the top. The bricks are placed on flat arches, having holes left in them resembling lattice-work ; the kiln is then covered with pieces of tiles and bricks, and some wood put in, to dry them with a gentle fire. This continues two or three days before they are ready for burning, which is known by the smoke turning from a darkish color to semi-transparency. The mouth or mouths of the kiln are now dammed up with a s/iinlog, which consists of pieces of bricks piled one upon another, and closed with wet brick earth, leaving above it just room sufficient to receive a fagot. The fagots are made of furze, heath, brake, fern, &c., and the kiln is supplied with these until its arches look white, and the fire appears at the top, upon which the fire is slackened for an hour, and the kiln allowed gradually to cool. This heating and cooling is repeated until the bricks are thoroughly burned, which is generally done in 48 hours. One of these kilns will hold about 20,000 bricks. Clamps are also in common use. They are made of the bricks themselves, and generally of an oblong form. The foundation is laid with place brick, or the driest of those just made, and then the bricks to be burnt are Intilt up, tier upon tier, as high as the clamp is meant to be, with two or three inches of brocze or cinders strewed between each layer of bricks, and the whole covered with a thick stratum of breeze. The fire place is perpen- dicular, about three feet high, and generally placed at the west end ; and the flues are formed by gathering or arching the bricks over, so as to leave a space between each of nearly a brick wide. The flues run straight through the clamp, and are filled with wood, coals, and breeze, pressed closely together. If the bricks are to be burnt off quickly, wiiich may be done in 20 or 30 days, according as the weather may suit, the flues should be only at about six feet distance ; but if there be no immediate hurry, they may be placed nine feet asunder, and the clamp left to burn off slowly. The following remarks by Mr. H. Chamberlain, on the drying of Ijricks, have an especial value from the great experience of that gentleman, and his careful observation of all the conditions upon which the preparation of a good brick depends : — 208 BRICK. " The drying of bricks ready for burniDg is a matter of great importance, and requii t ? more attention than it generally receives. From hand-made bricks we have to evaporut'.- some 25 per cent, of water bel'ore it is safe to burn them. In a work requiring the make of 20,000 bricks per day, we have to evaporate more than 20 tons of water every 24 hour.'^. Hand-made bricks lose, in drying, about one-fourth of their weight, and in drying and burning about one-third. The average of machine bricks — those made of the stiff plastic clay — do not lose more than half the above amount from evaporation, and arc, therefore, of much greater specific gravity than hand-made ones. " The artificial drying of bricks is carried on throughout the year uninterruptedly in sheds having the floor heated by fires ; but this can only be effected in districts where coal is cheap. The floors of these sheds are a series of tunnels or flues running through the shed longitudinally. At the lower end is a pit, in which are the furnaces; the fire travels up the flues under the floor of the shed, giving off its heat by the way, and the smoke escapes at the upper end, through a series of (generally three or four) smaller chimneys or stacks. The furnace end of these flues would naturally be much more highly heated than the upper end near the chimneys. To remedy this, the floor is constructed of a greater thickness at the fire end, and gradually diminishes to within a short distance of the top. By this means, and by the assistance of dampers in the chimneys, it is kept at nearly an equal temperature throughout. Bricks that will bear rapid drying, such as are made from marly clays or very loamy or siliceous earths, will be fit for the kiln in from 12 to 24 hours. Before the duty was taken ott' bricks, much dishonesty was practised by unprincipled makers, where this drying could be carried on economically. Strong clays cannot be dried so rapidly. These sheds are generally walled round with loose bricks, stacked in between each post or pillar that supports the roof. The vapor given oft' from the wet bricks, rising to the roof, escapes. This system of drying is greatly in advance of that in the open air, for it produces the ware, as made, without any deterioration from bad weather ; but the expense of fuel to heat these flues has restricted its use to the neighborhood of collieries. In 1845 attention was turned to the drying of bricks, and cxijcrimcnts carried cut in drying the ware with the waste lieat of the burning kilns. The caloric, after having passed the ware in burning, was carried up a flue raised above the floor of the shed, and gave oft' its spent heat for drying the ware. Although this kiln was most useful in jjroving that the waste heat of a burning kiln is more than sufficient to dry ware enough to fill it again, it was abandoned on account of the con- struction of the kiln not being good. " Another system of drying is in close chambers, by means of steam, hot water, or by flues heated by fire under the chambers. I will, therefore, briefly describe the steam chamber, as used by Mr. Beart. This is a square construction or series of tunnels or cham- bers, built on an incline of any desired length ; and at some convenient spot near the lower end, is fixed a large steam boiler, at a lower level than the drying chamber. From the boiler the main steam pipe is taken along the bottom or lower end of the chamber, and from this main, at right angles, run branch pipes of four inches diameter up the chamber, two feet ajjart, and at about three feet from the top or arch. From there being so close and shallow a chamber between the heating surface of the pipes and the top, and so large an amount of heating surface in the pipes, the temperature is soon considerably raised. At the top and bottom ends are shutters or lids, which open for the admission of the green ware at the upper end, and for the exit of the dry ware at the lower end of the chamber. Over the steam pipes are fixed iron rollers, on which the trays of bricks, as brought from the machine, are placed, the insertion of one tray forcing the tray previously put in further on, assisted in its descent by the inclination of the construction. The steam being raised in the boiler flows through the main into those branch pipes in the chamber, and from the large amount of exposed surface becomes condensed, giving off its latent heat. From the incline given to the pipes in the chamber, and from the main pipe also having a fall towards the boiler, the whole of the warm water from the condensed steam flows to the boiler to be again raised to steam, sent up the pipes, and condensed intermittently. The steam entering at the lower end of the chamber, it is, of course, warmer than the upper end. Along the top end or highest part of the chamber is a series of chimneys and wind- guards, through which the damp vapor escapes. The bricks from the machine enter at this cooler end charged with warm vapor, and as the make proceeds are forced down the cham- ber as each tray is put in. Thus, those which were first inserted reach a drier and warmer atmosphere, and, on their arrival at the lower end, come out dry bricks, in about 24 hours, with the strongest clay.s. In some cases the waste steam of the working engine is sent through these pipes and condensed. Bricks will dry soundly without cracking, &c., in these close chambers, when exposed to much greater heat than they would bear on the open flue first described, or the open air, from the circumstance of the atmosphere, although very hot, being so highly charged with vapor. In i)ractice, these steam chambers have proved many principles, but they are not likely to become universal, for they are very expensive in erection on account of the quantity of steam pipes, and involve constant expense in fuel, and require attention in the management of the steam boiler ; but their greatest defect is BRICK. 209 the want of a current of hot air through the chamber to carry off the excess of vapor faster than is now done. The attaining a high degree of temperature in these chambers is useless, unless there is a current to carry off the vapor. Why should this piping be used, or steam at all, when we have a large mass of heat being constantly wasted, night and day, during the time the kilns are burning ? and after the process of burning the kiln is completed, we have pure hot air flowing, from 48 to 60 hours, from the mass of cooling bricks in the kilns, free from carbon or any impurities ; this could be directed through the drying chambers, entering in one constant flow of hot dry air, and escaping in warm vapor. The waste heat during the process of burning can be taken up flues under the chamber, and thereby all the heat of our burning kilns may be economized, and a great outlay saved in steam pipes, boilers, and attention. It must not be forgotten, also, that so large an atmospheric con- denser as the steam chamber is not heated without a considerable expenditure in fuel. This drying by steam is a great stride in advance of the old flued shed, but practical men must see the immense loss incurred constantly from this source of the spent heat of the burning kilns, and that by economizing it, an immense saving will be effected in the manufacture. The kilns are constructed as near the lower end of these chambers as convenient." Mr. Chamberlain must be again quoted on the burning of bricks : — " I will now more fully describe a principle of burning which I have had in practice for the last six years, and which I can therefore recommend with great confidence. The great object in brick-burning is to attain a sufficient heat to thoroughly burn the ware with ^s small a consumption of coal as possible ; and with nearly an equal distribution of the heat over all parts, so that the whole of the ware, being subjected to the same temperature, may contract equally in bulk, and be of one uniform color throughout. The advantage is also gained of burning in much less time than in the old kilns, which, on an average, took a week ; and the management is so simplified that any man, even though not at all conversant with the manufacture, after he has seen one kiln burnt, will be able to manage another ; and the last, though not least, advantage is, that of delivering up to us the waste heat at the ground level, or under the floor of the kiln, to be used in drying the green ware, or in partially burning the next kiln. " Hitherto the heat has been applied by a series of fire-places, or flues and openings round the kiln, each exposed to the influence of the atmosphere ; and in boisterous weather it is very difficult to keep the heat at all regular, the consequence of which is the unequal burning we often see. The improvements sought by experimentalists have been the burn- ing the goods equally, and, at the same time, more economically. These are obtained l)y the patent kilns, as improved by Mr. Robert Scrivener, of Shelton, in the Staffordshire Pot- teries. The plan is both simple and effective, and is as follows : — A furnace is constructed in the centre of the kiln, mucli below the floor level, and so built that the heat can be di- rected to any part of the kiln at the pleasure of the fireman. First, the heat is directed up a tube in the centre to the top of the oven or kiln, and, as there is no escape allowed to take place there, it is drawn down through the goods by the aid of flues in connection witli a chimney. Tims, all the caloric generated in the furnace is made use of, and, being cen- tral, is equally diffused throughout the mass ; but, towards the bottom, or over the exit- flues, the ware would not be sufficiently burnt without reversing the order of firing. In order to meet this requirement, there is a series of flues under the bottom, upon which the goods are placed, with small regulators at the end of each ; these regulators, when drawn back, allow tlie fire to pass under the bottom, and to rise up among the goods which are not sufficiently fired, and thus the burning is completed. By means of these regulators the heat may be obtained exactly the same throughout ; there is, therefore, a greater degree of cer- tainty in firing, and a considerable saving of fuel, with the entire consumption of the smoke. From the fire or draught being under command, so as to be allowed either to ascend or descend through the ware during the time of burning or cooling, the waste caloric can be economized and directed through the adjoining kiln in order to partially burn it, or be used in drying off the raw wares on flues or in chambers. I have found the saving of fuel in these kilns, over the common kiln, 50 per cent. ; and to give an idea of the facility with which they can be worked, it is common for my men to fill the kiln, burn, cool, and dis- charge it in six days." — Chamberlain. There are numerous machines in use for the manufacture of bricks. For the manufac- ture of perforated bricks, Mr. Heart's machine is the most generally employed. Mr. Cham- berlain thus describes it : — " The most imiversally used die machine which lias been exten- sively worked up to the present time is Mr. Beart's patent for jjcrforated bricks. Tiiis gen- tleman, who is practically acquainted with these matters, in order to remedy the difliculties I have mentioned in expressing a mass of clay through a large aperture or die, hung a series of small tongues or cores, so as to form hollow or perforated bricks. By this means the clay was forced in its passage through the die into the corners, having the greater amount of friction now in the centre. Still, the bricks came out rough at the edge with many clays, or with wliat is termed a jagged edge. The water die was afterwards applied to this ma- chine, and tiie perforated bricks, now so commonly used in London, are the result. In Mr. Beart's machine, which is a pug-mill, the clay is taken after passing through the rolling-mill, Vol. III.— 14 210 BRICK. and, being fed in at the top, is worked down by the knives. At the bottom arc two horizon- tal elav-boxes, in which a phinger works backwards and forwards. As soon as it has reached the extremity of its stroke, or Ibrced the clay of one box through the die, the other box re- ceiving during this time its charge of clay from the pug-mill, the plunger returns and emp- ties this box of clay through a die on the opposite side of the machine. The result is, that while a stream of clay is being forced out on one side of the machine, the clay on the oppo- site side is stationary, and can, therefore, be divided into a scries of five or six bricks with the greatest correctness by hand. Some of these machines have both boxes on one side, and the plungers worked by cranks. This machine cannot make bricks unless the clay has previously passed through rollers, if coarse ; for any thing at all rough, as stone or other iiard substance, would hang in the tongues of the die. But the clay being afterwards pugged in the machine, is so thoroughly tempered and mixed, that the bricks, when made, cannot be otherwise than good, provided they are sufiiciently fired. As to the utility of hollow or perforated bricks, that is a matter more for the consideration of the architect or builder than for the brick-maker. Perforated bricks arc a fifth less in weight than solid ones, which is a matter of some importance in tran.sit ; but it takes considerably more power to force the clay through those dies than for solid brick-making. In the manufacture of perforated bricks, there is also a royalty or patent right to be paid to Mr. Beart." Mr. Chamberlain's own machine is in principle as follows {fcj. ^1a) : — The clay is fed into a png-mill, ])laced horizontally, which works and amalgamates it, and then forces it off through a mouth-piece or die of about 05 square inches, or about half an inch deeper, and lialf an inch longer than is required for the brick, of a form similar to a brick on edge, but with corners well rounded off, each corner forming a quarter of a 3-inch circle, for clay will pas.s smoothly through an aperture thus formed, but not through a keen angle. After the clay has escaped from the mill, it is .seized by four rollers, covered with a porous fabric, (moleskin,) driven at a like surface sjieed from connection with the pug-mill. These rollers arc two horizontal and two vertical ones, having a space of 45 inches between them ; they take this larger stream of rough clay, and press or roll it into a squared block, of the exact size and shape of a brick cdgcway.s, with beautiful sharp edges, for the clay has no friction, being drawn through by the rollers instead of forcing itself through, and is delivered in one unbroken stream. The rollers in this machine perform the functions of the die in one class of machinery, and of the mould in the other. They are, in fact, a die with rotating sur- faces. By hanging a series of mandrels or cores between these rollers, or by merely chang- ing the mouth-piece, we make hollow and perforated bricks, without any alteration in the machine. Jlessrs. Bradley and Craven, of Wakefield, have invented a very ingenious brick-making macliine : — It consists of a vertical pug-mill of a peculiar form, and greatlv improved construction, into the upper part of which the clay is fed. In this part of the "apparatus the clav under- goes a most perfect tempering and mixing, and, on reaching the bottom of the m'ill, thor- oughly amalgamated, is forcibly pressed into the moulds of the form and size of brick re- quired, which are arranged in the form of a circular revolving table. BRICK. 211 As this table revolves, the piston-rods of the moulds ascend an incline plane, and grad- ually lift the bricks out of the moulds, whence they are taken from the machine by a boy, and placed on an endless band, which carries the bricks direct to the waller, thus effecting the saving of the floor room. The speed of the several parts of the machine is so judiciously arranged, that the opera- tions of pugging, moulding, and delivering proceed simultaneously in due order, the whole being easily driven by a steam engine of about six-horse power, which, at the ordinary rate of working, will make 12,000 bricks per day; or, with eight-horse power, from 15,000 to 18,000. In consequence of the perfect amalgamation of the clay, and the great pressure to which it is subjected in the moulds, the bricks produced by this machine are perfect ; and from the stiffness of the clay used, less water has to be evaporated in the drying, thus saving one- half the time required for hand-made bricks, and avoiding the risk of loss from bad weather. A very ingenious and simple brick-making machine was constructed and patented by Mr. Roberts, of Falmouth, and it has been extensively worked by him in the parish of Mylor. Fig. 89 shows a plan of machinery combined, according to Mr. Roberts's invention, and ■fif). 9i) shows a side elevation, partly in section, a is a circular track, on which are fixed series of moulds, 6, at intervals, the form of moulds being according to the shape of bricks or tiles to be made. Each set of moulds is provided with movable bottoms, (one for each mould,) which are connected to the bar, c, so that they may be all simultaneously lifted by the lever, d. ln,fi(j- 90, one set of the moulds and apparatus used therewith is shown, and the several sets of moulds (the positions of which are in the drawing, ^^^. 89) are similarly provided, e is a roller, which is moved round on the track, a, by means of the frame,/, which receives motion from a steam-engine or other power, by means of the shaft, c/, the cog-wheel, /', and circular-toothed rack fixed on the frame,/. The clay, or brick earth, is filled into the moulds, and the roller, c, presses the same into the moulds as it rolls over them ; i is a scraper which, following the roller, e, removes any excess of clay or brick earth from the moulds ; and J is a smaller roller, which acts as a balance, to prevent the cutter from rising; k is a pressing plate attached to the bar, r, and is raised at the .«;ame time by the lever, d. T!ie roller, e, in its further progress, passes over and presses down the plate, /■, which com- pletes the pressure ; c then passes on and presses down the lever, rf, by which all the mov- able bottoms of the moulds will be raised with the bricks or tiles thereon. The whole of the pistons and bar, c, are kept up by the stop, /, which works by a spring, and is removed by the treadle, in, as soon as the bricks or tiles are taken away ; n are small rollers, fixed to the frame, o, to which the cutter or scraper is attached. 212 For the analyses of the clays of which these and others are constructed, see Clay. Stone Bricka. — These are manufactured at Neath, in Glamorganshire, and are rery much used in the construction of copper furnaces at Swansea. The materials of which the bricks are made are brought from a quarry in the neighbor- hood. They are very coarse, being subjected to a very rude crushing operation under an edge stone, and, from the size of the pieces, it is impossible to mould by hand. There are three qualities, which arc mixed together with a little water, so as to" give the mass co- herence, and in this .state it is compressed by the machine into a mould. The brick which results is treated in the ordinary way, but it resists a much greater heat than the Stour- bridge clay brick, expands more by heat, and does not contract to its original dimensions. The composition of the three materials is as follows : From Pondrevn. Silica - - - - . V 94-05 ". Alumina, with a trace of ox. iron 4-.5,5 . Lime and magnesia From Dinns. 100- 91-95 traces 8"05 traces traces 98-60 100- 100-00 — Dr. Richardson : Knapp's Technology. In immediate connection with this subject, it appears that the following machine for raising bricks, mortar, &c., by M. Pierre Journet, described to the London Institution of Civil Engineers, merits attention. It is a machine for raising bricks and materials to pro- 20 45 30 30 40 22 60 18 60 15 BRONZE. 213 gresive heights in the building of chimneys and other works. A strong frame on the ground contained the winch wheel, and on the second motion a notched wheel ; on the scaffold frame above is a similar notched wheel, and round these two wheels an endless chain travels, made of flat links and cross pins, which are held by the notches in the wheels. The buckets for mortar, and hods for bricks, are hooked upon these transverse pins, and are raised, by the winch motion below, to the landing above ; the bricks are removed by labor- ers, and empty buckets and hods hung to the descending chain, to be detached and filled below. It appeared that a working rate of 1 5 feet in a minute for the chain to travel was a con- venient rate for the men. One man turning the winch will raise — 10 feet high 90 bricks per minute, or = 5400 bricks per hour. " " = 2700 " " " " = 1800 " " « _ 135Q u u " " = 1080 " " " " = 900 " " As the work increases, the scaffold is elevated, and the chain lengthened, adding more hods. The great advantages are, that the men are relieved from the labor of climbing ladders and risk of accidents, that the building is carried on quicker, and therefore at less cost. The plan was adopted with success at the large buildings at Albert Gate, Hyde Park, and at the new Houses of Parliament. Steam power, of course, can be employed ; and a great practical advantage arises from not encumbering the building with the weight of ladders, and materials collected on the scaffolding. BROMINE. (Br. Atomic weight, 80. Density in liquid state, 2-97. Density of vapor by experiment, 5 "39 ; calculation on supposition of the density of hydrogen being 0-0692, 5-536.) One of the most active of the elements. It was discovered in 1826, by Balard, of Montpellier, in the bittern produced from the water of the Mediterranean. Bro- mine is a very interesting substance, and its discovery has had great influence on the pro- gress of theoretical and applied chemistry. It is the only element, save me.rcury, which exists in the fluid state at ordinary temperatures. It is found not only in sea water, but in numerous saline springs. It also exists in combination with silver and chlorine in some Mexican and Chilian minerals. Preparation 1. From bittern. — Chlorine gas is passed in for some time ; this has the effect of combining with the metallic base of the bromide present, the bromine being, in consequence, liberated. "When the bittern no longer increases in color, the operation is suspended, or chloride of bromine would be formed, and spoil the operation. The colored fluid is placed in a large globe, with a neck having a glass stopcock below like a tap funnel, the upper aperture being closed with a stopper. ■ Ether is then added, the stopper replaced, and the whole well agitated. After a short repose, the ether rises to the surface retaining the bromine in solution. The stopper being removed to permit the entrance of air, the stopcock is opened, and the aqueous fluid is permitted to run out. As soon as the highly colored etheral solution arrives at the aperture in the stopcock, the latter is shut ; a quan- tity of solution of potash is then poured, by the upper aperture, into the globe, and the stopper is replaced. The whole is now to be agitated, by which means the bromine com- bines with the potash, forming a mixture of bromate of potash and bromide of potassium. The stopcock is again opened, and the aqueous fluid received into an evaporating vessel, boiled to dryness, and ignited. By this means the bromate of potash is all converted into bromide of potassium. The bromine may be procured from the bromide of potassium by distillation with peroxide of manganese and sulphuric acid. In this operation one equiv- alent of bromide, two equivalents of sulphuric acid, and one of pcrpxide of manganese, yield one equivalent of sulphate of manganese, one of sulphate of potash, and one of bro- mine _; or, in symbols, KBr -f 2S0= -f MnO^ = KO, SO^ -f MnO, SO^ -j- ^r. The reac- tion, in fact, takes place in two stages, but the ultimate result is as represented in the equation. Preparation 2. — In some saline springs where bromine is present, accompanied by con- siderable quantities of salts of lime, &c., the brine may be evaporated to one-fourth, and, after repose, decanted or strained from the deposit. The mother liqiiid is to have sulphuric acid added, in order to precipitate most of tlie lime. The filtered fluid is then evaporated to dryness, redissolved in water, and filtered ; by this means more sulphate of lime is got rid of. The fluid is then distilled with peroxide of manganese and hydrochloric acid. The only well-developed oxide of bromine is bromic acid, BrO^ Solutions of bromine in water may have their strength determined, even in presence of hydrochloric or liydro- bromic acids, by means of a solution of turpentine in alcohol. One quarter of an equivalent of turpentine (34 parts) decolorizes 80 parts or 1 equivalent of bromine. — C. G. W. BRONZE. {Bronze, Fr. ; Bronze, Germ.) A compound metal consisting of copper and tin, to which sometimes a little zinc and lead are added. There is some confusion 214 BRONZE. amongst continental writers about this alloy ; they translate their bronze into the English brass. Sec, for an example of this, " Dictionnaire des Arts et Manufactm-es." This has arisen from the carelessness of our own writers. Dr. Watson, " Chemical Essays," remarks : '* It lias been said that Queen Elizabeth left more brass ordnance at her death than she found iron on her accession to the throne. This must not be understood as if gun metal was made in her time of brass, for the term brass was sometimes used to denote copper ; and some- times a composition of iron, copper, and calamine was called brass ; and we, at this day, commonly speak of brass cannon, though brass does not enter into the composition used for casting cannon." Bronze is an alloy of copper and tin. Brass is an alloy of copper and zinc. In niauy instances, we have zinc, lead, &c., entering into the composition of alloys of copper and tin. However this may be, the alloy is called a bronze, if tin and copper are the chief constituents. This alloy is much harder than copper, and was employed by the ancients to make swords, hatchets, &c., before the method of working iron was generally understood. The art of casting bronze statues may be traced to the most remote antiquity, but it was first brought to a certain degree of refinement by Theodoros and Roecus of Samos, about VOO years before the Christian era, to whom the invention of modelling is ascribed by Pliny. The ancients were well aware that by alloying copper with tin, a more fusible metal was obtained, that the process of casting was therefore rendered easier, and that the statue was harder and more durable. It was during the reign of Alexander that bronze statuary re- ceived its greatest extension, when the celebrated artist Lysippus succeeded, by new pro- cesses of moulding and melting, in multiplying groups of statues to such a degree that Pliny called them the mob of Alexander. Soon afterwards enormous bronze colossuses were made, to the height of towers, of which the isle of Rhodes possessed no less than one hundred. The Roman consul Mutianus found 3,000 bronze statues at Athens, 3,000 at Rhodes, as many at Olympia and at Delphi, although a great number had been previously carried off from the last town. From the analyses of Mr. J. A. Phillips, we learn that most of the ancient coins were bronzes, the quantity of tin relatively to the copper varying slightly. The proportions of copi)er and tin in many of those coins are given below, the other ingredients being omitted : — Copper. Tin. A coin of Alexander the Great, 335 B. c. - - 86-72 - - 13-14 " PhillipusV. - 200 B. c. - - 8.5-15 - - 11-10 " Athens 88-41 - - 9-95 " Ptolemy IX. - - 70 b. c. - - 84-21 - - 15-59 " Pompey - - 53 b. c. - - 74-11 - - 8-56 " the Atilia family - 45 b. c. - - 68-72 - - 4*77 " Augustusand Agrippa, 30 B, c. - - 78-58 - - 12-91 The arms and cutting instruments of the ancients were composed of similar bronzes, as the following proportions, also selected from Mr. J. A. Phillips's analyses, will show : — Roman sword blade, found in the Thames - " " " Ireland Celtic " " Ireland Laj-ard brought from Assyi'ia a considerable variety of bronze articles, many of them objects of ornament, Init many evidently intended for use. Amongst others was a bronze foot, which was constructed for the purpose of support of some kind. This was submitted to the examination of Dr. Percy. It was then found that the bronze had been cast round a support of iron. By this means the appearance of considerable lightness was attained, while great strength was insured. This discovery proves, in a very satisfactory manner, that the metallurgists of Assyria were perfectly conversant with the use of iron, and that they cm- ployed it for the purpose of imparting strength to the less tenaceons metals which they cm- ployed in their art manufactures. This bronze, as analysed in the Metallurgical Laboratory of the Museum of Practical Geolog)', consists of copper 88-37, tin 11-33. Examination has shown that all the bronze weapons of the Greeks and Romans were not only of the true composition for ensuring the greatest density in the alloy itself, but that these, by a process of hammering the cutting edges, were brought up to the greatest degree of hardness and tenacity. Before 1542 "brass ordnance" {bronze) was foimded by foreigners. Stow says that John Owen began to found brass ordnance, and that he was the first Englishman who ever made that kind of artillery in England. Bell founding followed. Bell metal and other broken metal were allowed to be ex- Copper. Tin. 85-70 - - 10-02 91-39 - - 8-38 90-23 - - 7-50 BEONZING. 215 ported hitherto ; but it being discovered that it was apphed to found guns abroad " brass copper, latten, bell metal, pan metal, gun metal, and shrolf metal are prohibited to be ex* ported." Bronze has almost always been used for casting statues, basso relievos, and works which were to be exposed to atmospheric influences. lu forming such statues, the alloy should be capable of flowing readily into all the parts of the mould, however minute; it should be hard, in order to resist accidental blows, be proof against the influence of the weather and be of such a nature as to acquire that greenish oxidized coat upon the surface which 'is so much admired in the antique bronzes, called patina antiqua. The chemical 'composition of the bronze alloy is a matter, therefore, of the first moment. The brothers Keller cele- brated founders in the time of Louis XIV., whose chefs-d'oeuvre are well known directed' their attention towards this point, to which too little importance is attached at the present day. The statue of Desaix, in the Place Dauphine, and the column in the Place Veudome are noted specimens of most defective workmanship from mismanagement of the alloys of which they are composed. On analyzing separately specimens taken from the bass-reliefs ot the pedestal of this column, from the shaft, and from the capital, it was found that the farst contained only 6 per cent, of tin, and 94 of copper, the second much less, and the third only 0-21. It was therefore obvious that the founder, unskilful in the melting of bronze had gone on progressively refining his alloy, by the oxidizement of the tin, till he had ex- hausted the copper, and that he had then worked up the refuse scoriaj in the upper part of the column The cannon which the Government furnished him for casting the monument COllSlStGCl 01 I~^ ^PPP^"* 89-360 1^'^, 10-040 ^5 0-102 Silver, zinc, iron, and loss 0-498 100-000 _ For the following table we are indebted to Mr. Robert Mallet, C. E., whose investiga- tions in this direction have been most extensive, and as accurate as they are extensive ■— Chemical Constitution. Compoaition by Weight per cent. Cu + Sn lOCix + Sn 9 0u+Sn 8Cu+Sn TCu+Sn 6Cu+Sn 5Cu+Sn 4Cii + Sn 3 Cu+Sn 2Cu+Sa Cu + Sn Cu+2Sn Cu+3Sn Cu+4Sn Cu+5Sn 100-()0+ 84-29+ 15-71 82-81+ 17-19i343-3 8-4G2 81-10+ 18-90 311-7 8-459 31-6 S0G7 374-9 8-561 78-97+ 21-03 76-29 + 72-80 + 68-21 + 61-69 + 51-75 + 34-92 + 21 •15 + 1.5-17 + 11-82 + 9-68 + 23-71 27-20 81-79 38-31 48-25 280-1 8-728 I 243-5 8-750 216-9 8-5T5 185-3 8-400 153-7 8-539 1'221 8-416 65-08! 90-5 8-056 78-85 149-4 7 387 I I 84-83 208-3 7-447 88'18;207-2 7-472 90-32:326-1 7-442 + 3n O-OO + lOO-Oo! 589 7-291 f White, 7 . Color of Fracture. Tile red - Reddish yellow, 1 Reddish yellow, 2 Yellowish red, " Yellowish red, 1 Bluish rod, 1 Bluish red, 2 Ash gray - Dark pray - Grayi.sh -white, 1 Whiter still, 2 Ditto 3 Ditto Ditto Ditto 2-5! 7 Commercial Titles, characteristic Propertiea in working, &c. Copper. Gun metal, &c. Ditto. Gun metal, tempers best. Hard mill brasses, l-e. Brittle.t Brittle.t Crumbles.t Crumblcs.-f- Brittle.t Small bells, brittle.! Ditto brittle.t Speculum : — Metal of authors. Fileii, tough. Files, soft and tough. Tin. In \S6(iyfe imported, of Bronze, works of art, 21 cwts. ; and of manufactures of bronze, or ot metal bronzed or lacquered, 3,492 cwts. BRONZING. The process for giving to metals, plaster, wood, or any other body, a bronze-hke surface. > i , , j j, . Various processes have been adopted for producing this effect. When brass castings are to be bronzed, it is essential, in the first place, that they should be tlioroughly cleansed from grease, and brightened either with the file or emery-paper or by boding in a strong lye and then scouring witii fine sand and water. " ' Vinegar alone is sometimes employed to produce the green bronze color ; sometimes dilute nitric acid, and often the muriate of ammonia, {sal amnwniac.) This latter salt and ^^:^^^^^SVc:'^^'^^2^'' PO,fln; crystalline; c, conchoidal; v, vitreous; v c, t All these alloys are found occasionally in bells and specula with mixtures of Zn and Pb. 216 BEONZE POWDEES, vincar are frequently combined, and often a little common table salt is added to the bronz- ing fluid. The best and most rapid bronzing liquid, which may be applied to copper, brass, iron, or to new bronze, with equal advantage, is a solution of the chloride of platinum {nilro- nntriate of platinum) called chemical bronze ; but it is expensive. With the chloride of platinum, almost any color can be produced, according to the degree of dilution, and the number of applications. Some beautiful effects are produced upon bronze, and also upon iron castings, by treat- in" them with dilute acids. The action here is scarcely to be described as bronzing ; it is, in fact, merely developing the true color of the metal or alloy. With the view of rendering the action of the bronzing liquid as uniform as possible, small articles are dipped ; for larger articles, the bronzing liquid is dabbed on plentifully with a linen rag. The dabbing process is to prevent the occurrence of streaks, which might arise if the liquid was applied in straight strokes. When properly bronzed and washed, the work is usualy black-leaded, to give it a polished appearance. BRONZE POWDERS have been much used of late in the decorative painting of houses, &c. They are prepared of every shade, from that of bright gold to orange, dark copper, emerald green, &c. Pale gold is produced from an alloy of 13^ of copper, and 2f of zinc ; crimson metallic lustre — from copper : ditto, paler, copper and a very little zinc ; green bronze, with a proportion of verdigris ; another fine orange by 14^ copper and If zinc ; another ditto, 13f copper and 2^ zinc : a beautiful pale gold from an alloy of the two metals in atomic proportions. The alloy is laminated into very fine leaves with careful annealing, and these are levi- gated into impalpable powders along with a film of fine oil to prevent oxidizement, and to favor the levigation. On the subject of bronze powders and metallic leaves, Mr. Brandeis furnished to the New York Exhibition an account of his articles of manufacture : — Bronzes, or, more correctly, metallic powders resembling (/old dicsf, were invented, ac- cording to my researches, in 1648, by a monk, at Furth, in Bavaria, named Theophrastus Allis Bombergensis. He took the scraps or cuttings of the metallic leaves then known as " Dutch leaf," and ground them with honey. This roughly made bronze powder was used for ornamenting parchments, capital letters in Bibles, choral books, &c. As the consumption of metallic leaf increased, and the properties of alloys became bet- ter known, leaves of different colors were produced, and from the scraps a variety of pow- ders or bronzes. At Furth, bronze powders are largely made for Europe, and with little change or im- provement. There are four sorts of Dutch leaf : Common leaf, soft, and of a reddish cast, composed of 25 or 30 per cent, of zinc to 75 or 70 per cent, of copper. French leaf contains more zinc, is harder, less ductile, and has a purer' yellow color. Florence leaf has a larger proportion of zinc, and is of a greenish gold color ; and lastly — Wliite leaf composed of tin. The more zinc these alloys contain, the harder, the more brittle, and more difficult are they to work into perfect leaves. The manner of beating is similar to the mode for producing gold leaves. The scraps, cuttings, and fragments of these leaves are the materials for the German bronze powders. First brushed through a sieve and ground with gum water on marble slabs for six hours, the gum washed out, the powders sorted, dried, and a coating of grease given to make them appeaj" more brilliant, and to protect them from oxidation. Varieties of color, such as orange, &c., are produced by a film of suboxide upon the surface of the' particles. The price of bronze powders depends upon the demand, and the supply of the waste material of the metal leaves, and prices change accordingly. Messrs. Brandeis patent their process, and in place of being dependent upon uncertain supplies of metal and unknown composition, they take the metals at once in a state of pu- rity, (say copper by voltaic precipitation :) it is alloyed with zinc, cast into ingots, rolled into ribands, cut, annealed, and rolled until the metal is thin and leaf-like ; then it is taken to a steam-mill, and ground. The bronze powder is washed out and dried, then introduced into an air-tight room, with an arrangement of boxes ; the air of the chamber is set in violent motion by bellows, and the powder diffused throughout ; the bronze powders are deposited, the finest in the upper boxes, and the coarser powders below. When settled, mineral var- nish is introduced ; tlie boxes, fitted with tight lids, are made to revolve, and the particles are thus rapidly coated, and the highest metallic brilliancy imparted. Different shades of color, pink, crimson, &e., are produced by submitting the powder to heat and oxidation before the rapid revolutions of the varnishing boxes. The quantity thus produced by orre firm, with three steam-engines at work, enables the finished bronze powders to be produced at a rate about equal to the price the German manufacturer has to pay for his materials — the cuttings and scraps of leaves. Hence, for BEOWN lEON ORE. 217 the purposes of trade and art, a large exportation of bronze powders takes place from America to Europe, South America, and China. The bronze powders are largely used in japanning, bronzing tin and iron goods, orna- mental woriis of paper, wood, oil-cloth, leather, &c. ; while sign-boards and the decoration of public buildings have effective metallic brilliant surfaces of beauty and durability. lu fact, for ornamental decorations, the demand steadily increases. In Ilolland and Germany the subject has been examined, with the view of ascertaining the effect of chemical composition. De Heer E. R. Konig has lately given a table of the analyses of the best European sam- ples of bronze powders and leaves, ( Volkujlight :) — Copper. Zinc. Iron. Tin. Per cent. Per cent. Per cent. Per cent. 1. Light yellow - . . . . 82-38 1C)-G9 0-16 2. Gold yellow 84-50 15-30 0-07 3. Messing yellow, or brass copper red-yel- low color 90- 9-Gl 0-20 4. Copper bronze orange - - - . 98-93 0-Y3 0-08 5. Copper red, high shade of purple color 99-90 0-00 trace. 6. Purple violet 98-22 0-5 0-30 trace. 7. Light green 84-32 15-02 0-03 trace. 8. Tin white or leaden gray 0-00 2-39 0-56 97-40 Our importations in 1856 of Bronze Powders were valued at £4,737, according to the Custom House computation. BROWX COAL is of a brownish-black color, and presents, in some cases, the texture of wood, when it is called Lignite ; but, in some varieties, all organic structure has disap- peared, and it is then called pitch coal, from its strong resemblance to true coal. The beds of brown coal are generally of small extent, and are of hater date than the true carboniferous strata, belonging to the Tertiary period. Brown coal is worked in Saxony and in countries where there is an absence of true car- boniferous deposits. It burns with an empyreumatic odor, and generally contains more pyrites than ordinary coal. At Steieregg, in Southern Styria, brown coal occurs in the form of a basin ; and has been opened out through a distance of more than two miles. The coal, from 8 to 10 feet thick, is of good quality. It contains 9 to 14 per cent, of water, and leaves from 5 to 12 per cent, of ash after combustion. The following is an analysis of a variety from Oregon : volatile matter, 49 5 : fixed car- bon, 42-9 ; ash, 2-7 ; water, 4-9 = 100-00. A variety of brown coal, called the paper-coal of Rott, near Bonn, and of Erpel on the Rhine, contains numerous remains of freshwater fishes, Leuciscus papyraceus ; and of fro"-s, Palmopknjgnos grandipes. The ashes of this coal are, also, rich in infusorial remains. For an account of the brown coals of this country, see Lignite and Boghead Coal n. w. B. BROWN" IRON" ORE (or Limonite) is one of the most important ores of iron, and, at the same time, one of the most abundant as well as most widely diffused. It never occurs crystallized, but usually in stalactitic, botryoidal, and mammillated forms, with a fibrous structure, a silky lustre, and often a semi-metallic appearance ; it also occurs massive and sometimes earthy. In color it is of various shades of brown, generally dark, never brio-ht It affords a brownish-yellow streak, which distinguishes it from other ores of the same m^tal. It dissolves in warm nitro-muriatic acid, and in a matrass gives off water. Before the blow- pipe It blackens and fuses, when in thin splinters ; with borax, it gives an iron reaction. H = 5 to 5-5 ; specific gravity = 3-0 to 4. Brown iron ore is a hydrated peroxide of iron, composed of peroxide of iron, 85-6, and water, 14-4 = 100-0; but it frequently contains small percentages of silica, alumina, &c. The principal varieties of this ore are brown hematite, comprising the compact and mammiUary varieties, scaly and ochry brown iron ore, yellow ochre constituting the decom- posed earthy varieties, which are often soft, like chalk. Bog iron ore and clav iron stone are sometimes classed under this head, but it appears to us, especially as it regards the lat- ter, improperly. The hydrated oxides of Northamptonshire and Bedfordshire mav with propriety be called brown iron ore. Brown iron ore is found in Cornwall, in the cnrlwniferous limestone at Clifton near Bristol, and in the Forest of Dean ; in Shetland, Carinthia, Bohemia, Siegen near JBonn V lUa Rica in the Brazils, and Peru. Brown Hematite occurs at Talchcer, in the Bengal coal-bearing strata, which are prob- ably of Permian age. It is smelted with the charcoal made on the spot, and produces iron 218 BEUCINE. of excellent quality. According to the calculations of Professor Oldham, it takes 2^ toub of charcoal to produce 1 ton of iron. — H. W. B. See Irox. BRUCINE. (C^^H-^N'-O" ; syn. Canimarine, Yomicine.) A very bitter and poisonous alkaloid accompanying strychnine in nux vomica and in the false angustura bark, {Brucia antidi/seiiterica. ) BKYLE or BROIL. A mining term. The loose matters found in a lode near the surface of the earth ; probably a corruption of Beliievl, [v:/iic/i stc) BRUSH WHEELS. In light machinery, wheels are sometimes made to turn each other by means of bristles fixed in their circumference ; these arc called brush ■wheels. The term is sometimes applied to wheels which move by their friction only. BUCKING. A juiuing term. Bruising of the ore. A lucking iron is a flat iron fixed on a handle, with wliich the ore is crushed ; and a bucking plate is an iron plate on which the ore is placed to be crushed. BUCKTHORN. {Rhamnus catharticua.) This plant is a native of England ; it grows to the height of from 15 to 20 feet ; its flowers are greenish colored, and its berries four- seeded. It is the fruit of this plant which is sold under the name of French berries. The juice of these, when in an unripe state, has the color of saffron ; when ripe, and mixed with alum, it forms the sap-green of the painters ; and in a very ripe state, the berries afford a purple color. The bark also yields a fine yellow dye. BUCKWHEAT. {Bli- Sarrasin, Yv. ; Buchwcizcn, Germ.) The common buckwheat {Polygonum fagopyrum ^ from poly^ many, and gonu, a knee, in reference to its numerous joint.s) is cultivated for feeding pheasants and other game ; and is now being largely used in France and in this country in distilleries. " In France, besides being used for feeding fowls, pigs, &c., it is given to horses ; and it is said that a bushel of its grains goes further than two bushels of oats, and, if mixed with four times its bulk of bran, will be full feeding for any horse for a week. Its haulm, or straw, is said to be more nourishing than that of clover, and its beautiful pink or reddish blossoms form a rich repast for bees." — Bauso7i. It has been stated that the leaves of the common buckwheat (Polygonum fagopyrw?)) yield, by fermentati«5n. Indigo blue. On examining this plant, for the purpose of ascertain- ing whether this statement was correct, Schunck was unable to obtain a trace of that coloring matter, but he discovered that the plant contains a considerable quantity of a yellow coloring matter, which may very easily be obtained from it. This coloring matter crystallizes in small primrose-yellow needles. It is very little soluble in cold water, but soluble in boiling water, and still more soluble in alcohol. Muriatic and sulphuric acid change its color to a deep orange, the color disappearing on the addition of a large quantity of water. It dis- solves easily in caustic alkalies, forming solutions of a beautiful deep yellow color, from which it is again deposited in crystalline needles on adding an excess of acid. It is, how- ever, decomposed when its solution in alkali is exposed for some time to the air, being thereby converted into a yellowish-brown amorphous substance, resembling gum. Its com- pound with oxide of lead has a liright yellow color, similar to that of chromate of lead. The compounds with the oxides of tin are of a pale but bright yellow color. On adding proto- sulpliate of iron to the watery solution, the latter becomes greenish, and, on exposure to the air, acquires a dark green color, and appears almost opaque. The watery solution imparts to printed calico, colors, some of which exhibit considerable liveliness. Silk and wool do not, however, acquire any color when immersed in the boiling watery solution, unless they have previously been prepared with some mordant. The composition of this substance in 100 parts is as follows : — carbon, 50-00, hydrogen, 5'55, oxygen, 44'45. Its formula is probably C^"H""0-°. It appears to be identical with Rutine, the yellow coloring matter contained in the Ruta graviolen.'i, or common rue, and in capers ; and with IHxanthlm, a substance derived from the leaves of the common holly. From 1,000 parts of fresh buck- wheat leaves, a little more than 1 part of the coloring matter may be obtained. As the seed of the plant is the only part at present employed, it might be of advantage to collect and dry the leaves, to be used as a dyeing material. — E. S. The Tartarian Buckwheat {Polygonum Tartarium) differs from the former in Laving the edges of its seeds twisted. It is not considered bo productive, but it is more hardy, and better adapted for growing in mountainous situations. The Dyers' Buckwheat. (Polvf/oman tinctorium.) This plant was introduced to the Royal Gardens at Kew by Mr. John Blake, in ITTG. Authentic information as to its properties as a dye-yielding plant was only received at a comparatively recent period, from missionaries resident in China, where it has always been cultivated for its coloring matter. In Europe, attention was first directed to its growth by M. Delile, of the Jardin du Roi at Montpcllier, who, in 1835, obtained seeds from the Baron Fischer, Director of the Imperial Gardens at St. Petersburg. It has since that time become sufficiently valuable to render its cultivation as a dye drug of sufficient importance. The Japanese are said to extract blue dyes from Polygonum Chinensis, P. barbatmn,.o.u'\ the common roadside weed, P. avicu- lore. — Lawson. CABLE. 219 BUDDLING. A mining term. The process of separating the metalliferous ores from the earthy matters with which they are associated, by means of an inclined hutch, called a huddle., over which water flows. It is indeed but an arrangement for availing ourselves of the action of flowing water to separate the lighter from the heavier particles of matter. BUHL. Buhl-work consists of inlaid veneers, and differs from marquetry in being con- fined to decorative scroll-work, frequently in metal, while the latter is more commonly used for the representation of flowers and foliage. Boule, or Buhl, was a celebrated cabinet- maker in France, who was born in 1642, and died in 1732. He was appointed " Tapissier en titre du Roi," and he gave his name to this peculiar process of inlaying wood with either wood or metal. See Makquetrt. BUHR-STONE, mineralogically, is a cellular flinty quartz rock, constituting one of the jaspery varieties of the quartz family. A celebrated grit-stone, much used in France and other parts of the continent for grist-mills. Those of La Ferte-sous-Jonarre (Seine ct Maine) are regarded as superior to all others. In consequence of the necessity for carefully piecing these stones together, they are naturally expensive ; yet the demand for buhr-stones continues great. BULRUSH, or TALL CLUB. {Scirpus lacustris ; Celtic, cirs, rushes.) The bulrush, belonging to the natural order of Cypcraccce, grows naturally on alluvial soils which are occasionally covered with fresh water. It is much used by coopers for putting between the staves of barrels, and by chair-makers. Many other plants belonging to this order are cm- ployed for economical purposes, such as forming seats, ropes, mats, and fancy basket-work, also for thatching houses. In 1856, we imported 562 tons. BURGUNDY PITCH. Burgundy pitch, when genuine, is made by melting frankin- cense {Abieiis resina) in water, and straining it through a coarse cloth. The substance usu- ally sold as Burgundy pitch is, however, common resin, incorporated with water, and colored with palm oil. In some cases American turpentine is cmijloyed. See Pitch and Tar. BURNING HOUSE. A miner's term. In Cornwall the kiln or oven in which the tin and other ores are placed to sublime the volatile constituents, sulphur, and arsenic, is so called. BURROW. A miner's term for a heap of rubbish. BUTT. A measure for wine, &c., containing 2 hogsheads, or 126 gallons. BUTYLAMINE (C^H"N.) A volatile organic base, homologous with melhylamine. It is found in the more volatile portion of bone oil. It may be prepared artificially by pro- cesses analogous to those employed for methylamine, amylamine, &c., substituting the butylic cyanate, urea, or iodide, for those of methyle and amyle. — C. G. W. c CABLE. We have avoided all relating to the general history and application of chain cables, but in connection with the following particulars, obtained from Brown, Lenox, and Co.'s chain works at Millwall, we must admit the important part performed by this house in the improvement of this manufacture. The following i-emarks refer to chain cables for the Royal Navy, messenger and mooring chains for the Trinity Corporation, and ship cables for merchant service, showing the practice in 1858. After selecting the best iron, cutting it off" into required lengths, and heating it, the links for chain cables may be bended at the rate of about 60 per minute, by machinery at Lenox's works in Wales, woi-ked by water power, — the welding of the links, in all cases, being effected by hand labor. In the practice with the new hcndinc/ machine at New bridge Works, Pont-y-Prid, Glamor- ganshire, it is as follows : — When the iron is cut to the requisite length for links, from 20 to 60 pieces, according to size, are put into the furnace, and, when heated, are placed separately on the bending mandrel g, {fig. 91,) the machine is set in motion, and one revolu- tion forms a link which is pinched off the mandrel by a small crowbar, and another piece of iron applied, and so on, until from 40 to 60 links arc formed in a minute. The bending machine is connected with a water-wheel, or other power, by an ordinary coupling clutch, or box, wliich a lever throws into and out of gear at pleasure. There is a stub or knob of iron on the mandrel under which the point of the piece of iron to be bent is fixed ; the mandrel being oval, or of the inside shape of the link, when turned, is followed by the roller above, and this, pressing upon the piece of iron, forms it to 'the shape of the mandrel. ABC {fig. 91) are standards, d, connecting rod, e, crank for lifting, f f, the roller for pressing sides of links, (;, mandrel, ii, mandrel spindle, i, wheel for mandrel spindle, j, pinion or main spindle, k, crank spindle. The form of the link, after being bended into shape, (^fig. 01,) is shown with the two slant- cut surfaces of the ends to I)e welded together and hammered into form. For short lengths of chain, the bending may be efi'ectcd by hand ; in this case the pro- 220 cess is simple : — A sufficient length of the best iron is cut off, and, while hot, is partialh- bent by the workman over an iron ring, one end of the bar resting on the ground ; the bend is finished upon the anvil ; one entire length of the link is thus formed. The two slanting cut ends are made to approach each other ; heated up to a high temperature, the expert workman, by a peculiar blow, detaches the scale of oxide, and instantly presses both surfaces together ; two men then, by repeated blows, effect the welding junction, and thus the link is formed. The shape of the link, after due consideration of the advantages of particular patterns, seems to resolve itself into the decided preference for a link of parallel sides, unchanged in form from the round of the iron employed, while the ends may be reduced somewhat flattened, and increased in breadth. The links thus in contact have the pressure sustained by a greater breadth of surface, and compression can scarcely alter the form. The length of a good link may be of round iron 6 diameters in length of link. (See fri. 92.) A a and from b to 6 3'7 to 4 diameters of the iron rod employed, and 1-7 to 2 diameters inside. The stud, staple, or cross-bit is of cast-iron, and is placed across ; its use is to prevent the sides from collapsing by extension of the chain ; in fact, to keep up a succession of joints, and prevent the chain from becoming a rigid bar of metal. The stud or cross-piece shown at c is of cast-iron, with dates and marks upon the sur- face. It is cast with a hollow bearing, having a curve to receive the round iron of the link ; its shoulders, or feathering, enaljlcs the workman to insert it readily, and a few blows upon the yielding iron give the requisite grip, and all proper service only tends more firmly to keep it in position. In all cases, this cross-piece has been of cast-iron. Wrought iron was tried, but found to be too expensive. Malleable iron has been patented, but it is a question whether it can supersede common foundry iron, from the cheapness and fiicility of the latter. The caViles are proved and tested by regulated strains brought to bear continuously up to the proof strain, and then even up to the ultimate destruction of some of the links, if t!ie final strength or opposition to resistance is required to be known. The proof of cable should be GOO Ihs. for each circle of iron \ of an inch in diameter. Tlie chain is attached at one end horizontally to a hydraulic press, the other end to the enormous head of a bent iron lever, whose power is multiplied by second and third iron lovers, all working upon knife edges, and to the last lever a scale-pan is attached ; 1 lb. being here placed as equivalent to a strain of 2,240 lbs. upon the bar or chain that is being tested. This machine of Brown, Lenox, and Co., Millwall, is more powerful than that used in the Royal Dockyard. The proving machine, invented by Captain Brown in 1813, was a great step towards the production of confidence. In practice, lcn()th after hnfjth is tried up to the proof required ; when the tension is to be exerted to the utmost, a few links are taken : in such experiments, it is usual for one CABLE. 221 link alone to give way, and the strength of the cable itself is uninjured by testing to find ita ultimate strength. Perfection of practice is found when the link and the stay yield together ; in the largest chain cables ever produced, such were the due proportions and symmetry of form affording equality of resistance, that the cross-piece split or broke at the time the link fractured and opened. To measure these chains, or be near them when under such tension, is not without dan- ger. The cable, on being struck, rings out with strange shrill sound, a link may suddenly snap, the chain lashes about, and the fragments fly to a great distance, penetrating the fac- tory roof at times, and, at the moment of fracture, the link becomes very hot. The cables are usually told off into lengths. The Government length is 12i fathoms ; for the merchant service the length is 15 fathoms; as explained, these lengths are united by shackles. In the merchant service cables, larger links are placed at eacTi extremity for the anchor shackle to pass through ; but in the Royal Navy cables each length is alike pro- vided with large links ; thus, then, at any time, any end of any length may be placed to the anchor stock. See Jigs. 92, 93. To obviate evils from the twisting of the chain cable, swivels are inserted : in the Gov- ernment cables, a swivel is inserted in the middle of every other length ; for the merchant service there does not appear to be any precise rule. Sometimes one, two, or more swivels may be in 100 fathoms ; and in cheap chains, bought and judged by weight and figures, no swivel whatever exists in the cable. The effect of such twisting, or torsion, is to form a kink, and give powerful lateral pressure upon the link ; the stud or cross-piece is forced out, and the link itself may yield at the moment at any flaw or imperfection of welding. The mooring swivel is that by which a ship can ride with two anchors down at the same time, and two bridles on board the ship. The mooring swivel, being equal in strength to the two cables, is over the bow, and enables the ship to swivel round her anchors without fouling hawse ; in any direction the ship can swing round this swivel or point, leaving her anchors undisturbed, whereas, by two cables out, without this, she would require groat care to prevent them from fouling, and even being lost. This is an essential advantage of chain over hemp. The splicing shackle is to unite or splice a hempen cable to be used on board ship, at- tached to the chain cable, which lies on the ground or bottom, so that the vessel rides lightly at her anchor, while tlie iron chain cable preserves the hempen cable from being de- stroyed by the rocky bottom, and the ship has the light hemp cable rendered buoyant by the water, which lifts portions of the chain cable by tlu^ motions of the vessel ; and thus, the ship is relieved from weight and the anchor from jerks. The splicing shackle, on the Hon. George Elliott's plan, is shown above, {Jig. 93.) The rope is served round an iron thimble, a, on the shackle, n, with end links," and enlarged links without stay-pins, c d, leading to the anchor, while the hempen cable, a, goes to the ship. In the Royal Navy 4 cables are employed to moor the ships, two being end to end. - When ships lay long on certain shores, the pin or fastening often gets loose by the con- stant tapping and vibrations of the chain cable on the rocky or shingly bottoni. Men-of-war at some stations suffered severely in this way, and the commander at Malta had reason to represent it as a very serious matter. Mr. Lenox's plan for securing the bolts and pins is now made a point of contract to be adopted in all fastenings for the Royal Navy. Simple as it would seem to devise a plan, yet it was years before all the difficulties could be surmounted. This arrangement may be understood by reference to the figure of a 222 CABLE. ^zy shackle with links, {fig. 94 :) at e is seen the aperture at right angles to the bolt, f, (of oval iron ;) through this channel, cut through the shackle and the bolt, a tapering but not quit cylindrical steel pin fits exactly, but does not quite proceed through the iron ; it is shown at g g. Various plans used to be resorted to before this final preference ; for the steel pins, of whatever form, got loose by repeated tap- ping on the rocky bottom, or the links upon each other. Mr. Lenox succeeded in cutting c ^ =^— — ...^ the cavity at e of the form of a hollow cone, ^ ^ \ / ,^_X^,?;^^1^^ ^^^ *^ complete the fastening, a pellet or cyl- inder of lead that will just allow insertion at i; is driven, and then, by rtpeated blows, the lead is made to fill up the cavity, the superfluous quantity of lead being cut oft" by the hammer at E. To release the bolt, it is only necessary to find the small space at the small end of the steel pin, to insert a punch, and then, with a few blows, the steel pin g g is driven out of its conical bearing, and its flat top and cutting edges enable it to emerge again at e. Being forced out, the bolt f is taken out, and the chain severed, if required ; the aperture at e can be cleared of its lead by a proper cutting-out tool, and the steel pin replaced to make all fast. This operation can be effected on the darkest night ; the sailor can sever the chain cable, and thus, when one vessel is driving down upon another, more chain may be attached, or the cable severed, and no harm done ; while with hempen cable it might be found more than difficult, and even impossible, to cut them in time. All the principles involved, and perfection of practice, in making chains and chain cables, have recently be(?li deeply considered and fully verified by the firm of Brown, Lenox, and Co., Millwall, who, for the purpose of obtaining comparative results up to the greatest links required for the " Leviathan," selected iron of the same identical quality and worked it into rods, links, and chains. The progression of resistance to increased strains, by increase of mass of iron, with all the influences of variation of make, flaws in the material, and oth.cr circumstances inseparable from practice, were thus matters of critical experiment. Commencing with ^-inch chain, and trying 4 links of small chains up to 2|, being the largest diameter of round iron for the greatest cable links ever hitherto made, being those for the sheet anchor of the " Leviathan," taking the breakirg strains, and reducing all the links to the proportion borne upon a circle ^ of an inch in diameter, the minimum breaking force was 796-25 lbs., and the maximum 1052'8 lbs. Sometimes the fracture was found to be dependent upon flaws, sometimes from over- heating, or unequal heating, and other practical causes ; but the whole series of experiments was important and interesting. The iron lengthens to the intense strains employed, long before fracture. The com- parison of actual extension, while under enormous force at ordinary temperatures, was as- certained by the following impressive experiments : — The " Leviathan " second-size cable of 2f diameter of iron employed in the links. Three links measured 35^ inches by strain of 10 tons, (of course, it requires power to extend them fairly.) At 50 tons stretched \ of an inch. u II u - - " H - - " n -Tff - - " 3i " 8-J- " 3f A few links of the best bower anchor cable of the " Leviathan " taken, proved, and destroyed. Three links measured at 15 tons 39 inches. 85 110 (Proof) " 124 140 150 160 170 ind broke " 180 At 75 tons 125 (Proof) " 148| IGO 170 180 190 200 It bore " 217 And broke " 218 stretched J of an inch. " If " 2^- " 3 " " 3i H CALICO PKINTING. 223 CACAO. The Theobroma Cacao (or Food of the Gods, as Linnaeus named the tree) is a native of the West Indies and of continental America, Its seeds, {nuclei Cacao,) when torrefied, and with various additions (sugar, and usually either cinnamon or vanilla) made into a paste, constitute Chocolate, (chocolata,) wliich furnishes a very nourishing bev- erage, davoid of the injurious properties ascribed to both tea and coffee ; but which, on ac- count of the contained oil, is apt to disagree with dyspepti(!S. Cocoa is another preparation of these seeds. It is said to be made from the fragments of the seed-coats, mixed with portions of the kernels. — Pereira. See Chocolate. CAIRNGORUM, or CAIRNGORM is the name generally applied to the more pellucid and paler-colored varieties of smoky quartz, with a tint resembling that of sherry or amber. It is so called from the district Cairngorum, or the " Blue Mountain," in the south-west of Banff, where these crystals are frequently found. When of a good color, this crystal is made into ornaments, and used for jewellery ; indeed, so great a favorite is the Cairngorum witli the people of Scotland, that brooches, pins, bracelets, and a variety of ornaments, are made with this stone, for use by all classes. CALAMANDER. A wood, the produce of Ceylon. See Coromandel. CALAMINE. A native carbonate of zinc. (See Zinc.) The term Calamine, or Lapis calnininariH, has been applied to this ore of zinc since the days of the Arabian alchemists. It is so used now by Brook and Miller, by Greg and Lettsom, and others ; yet we find Dana defining calamine to be the hjidroufi silicate of zinc, — another example of the sad want of system, and indeed of agreement, among mineralogists. CALCAREOUS EARTH {lerre cak-aire, Fr. ; Kalkerde, Germ.) commonly denotes lime, in any form ; but, properly speaking, it is pure lime. This term is frequently applied to marl, and to earths containing a considerable quantity of lime. CALCAREOUS SPAR. Crystallized native carbonate of lime, of which there are many varieties. Carbonic acid 44"0, lime 56'0, may be regarded as the usual composition of calc spar; it often contains impurities, upon which depend the colors assumed by the crystal. The car- bonates of lime are extensively distributed in nature, as marbles, chalk, and cr)'stalline minerals. CALCAREOUS TUFA. This term is applied to varieties of carbonate of lime, formed by the evaporation of water containing that mineral in solution. It is formed in fissures and caves in limestone rocks, about the borders of lakes, and near springs, the waters of which are impregnated with lime. In the latter cases it is fre- quently deposited upon shells, moss, and other plants, which it covers with a calcareous crust, producing frequently a perfect representation in stone of the substance so enveloped. — H. W. B. CALCEDONY. See Chalcedony. CALCINATION, (from Calcine.) The operation of expelling from a substance, by heat, either water, or volatile matter combined with it. Thus, the process of burning lime, to expel the carbonic acid, is one of calcination. The result of exposing the carbonate of magnesia to heat, and the removal of its carbonic acid, is the production of calcined mag- nesia. This term was, by the earlier chemists, applied only when the substance exposed to heat was reduced to a calx, or to a friable powder, this being frequently the oxide of a metal. It is now, however, used when any body is subjected even to a process of roasting. CALCIUM. {Equivalent 20.) The metal contained in the oxide well known as lime. It was first obtained by Davy, in 1808, by the electrolysis of the hydrate, carbonate, chlo- ride, or nitrate of lime. Matthiessen obtains it by heating, in a porcelain crucible, a mix- ture of two equivalents of chloride of calcium, with one equivalent of chloride of strontium, and muriate of ammonia, until the latter is volatilized. The current from six cells of Bun- sen's battery is then sent through the mixture by a cliarcoal pole of as largo size as possible, and a piece of iron piano-forte wire (No. G) not more than two lines in length, which is united with the negative pole of the battery by means of a stronger wire reaching close to the surface. A small crust is to be formed round the wire at the surface. To collect the small globules deposited on the wire, the latter must be taken out every two or three minutes, together with the crust. The globules are crushed in a mortar, an.j>>>^->'>>,-w/>??:w;>j>^s>fta>>p/j>yojfy^^ ^////^^^y^,^^^^.,^^ o • /^. o ' o 9 2 2 c , % 6C ' 6Qi c Where colors are required to melt into one another, technically called rainbowcii, (/onrfws, Fr.,) the following apparatus is used: — a a {fifj. 97) is a rectangular frame of CALICO PRINTING. 227 wood, about 6 inches deep, 2 feet long, and about 1 foot broad. On this frame is stretched, by means of small hooks, a woollen cloth, and the frame then laid on the elastic surface of the usual swinwdng tub, the cloth downwards and pasted or gummed to the oilskin cover of the tub. At one end is now put the color reservoir b b, which consists of a wooden or metal box, divided into water-tight compartments longitudinally by strips of thin metal ; this box is of such a width a^ to tit easily into one end of the frame, and resting on a board of the same size, fixed across the frame ; the depth of the box may be about 4 inches, and the width about 8 inches ; but this is regulated by the number of colors to be blended or ralnbowed. A semicircular piece of wood, of nearly the same width as the frame, is cov- ered with printer's blankets, and a handle formed on the top, so that the teerer can move it backwards and forwards. The color lifter, c c, is a flat piece of wood just covering the color box ; on the under side of this are inserted wooden pegs, as d, at certain places de- termined by the width of the stripe of rainbowed color, and the number of shades composin"- it. These pegs are of turned wood, about ^ of an inch thick at the small end, and about # of an inch at the thick end, this end being also recessed so as to lift more color ; they are nearly as long as the color box is deep. In the figure, suppose it is desired to produce on the sieve two stripes, say E of dark green in centre, and two shades of green at each side, and F of chocolate in centre, purple next, and drab next, at each side, the color-box is filled thus : — in No. 1 compartment is put the darkest green ; in No. 2, the medium green ; in No. 3, the palest green ; in No. 4, the chocolate ; in No. 5, the purple ; and in No. 6, the drab. The color lifter is so studded with pegs, that when put in the color-box, the pegs 1, 2, 3, 4, 5, and 6 respectively, dip into their appropriate colors. The brush, or semicircular roller,^ G, is then moved up to the top, as shown in the dotted lines, the color lifter being then lifted up out of the color-box is held a moment till the color has ceased dropping from the pegs, and then lifted over, and the pegs allowed to deposit the color on the sieve, as shown by the black spots 1, 2, 3, 4, 5, and 6. The lifter is then returned to the box, and a fresh portion of color lifted, and deposited, as befojre, at a different part of the sieve, the spots of color being of necessity all in straight lines ; the brush, g, is then moved back- wards and forwards by the teerer till the colors are sufficiently rubbed together or blended at the edges. It is necessary to observe, that the thickness of the colors must be pretty uniform, and sufficiently thin to allow them to mix at the edges. By this means one color is made to melt insensibly into another, and a beautiful shaded effect produced on the sieve, and consequently on the piece, when printed from a block dipped on it. The annexed cuts are taken from the " Traite de I'lmpression des Tissus," of M. Persoz. Fig. 98 is a vertical section, and7?y. 99 an elevation. A, cast-iron framework, b b b, cast-iron tables, planed smooth, over which circulate the blanket, the backcloth, and the piece that is printed ; c c c, sliding pieces, to which the block 228 CALICO PRLS'TIXG. holders, 3, are screwed, and causing the engraved blocks, 2, to more alternately against the woollen surface, from which they receive the colors and the stuff to be printed, by the action of the arms, 4 and 5, the supports of which, 6, rest on the frame, a, and which act, through the medium of connecting rods, on the beams, 7, keyed to the slides, c. The lower of these slides, being in a vertical position, takes by its own weight a retrograde movement, regulated by a counterweight, e e e are movable color-sieves, keyed to connecting rods, and receiv- ing from the power applied to the machine the kind of movement which they require. These sieves, which are flat, and covered with cloth on the surface opposite to the blocks, slide in grooves on the sides of the tables, and receive from the furnished rollers the colors which they aften^ards transmit to the blocks, f f f are the color troughs filled with color, and furnished each with two rollers, 8 and 10, the last of which, dipping into the troughs, are charged with color, which they communicate to the roller, 8, the latter being covered with woollen cloth ; and these, in their turn, transmit their color to the sieves, e, on which it is spread by the fixed brushes, 9. As it is important to be able to vary at pleasure the quantity of color supplied to the sieves, and consequently to the blocks, the rollers, 10, are in connection with levers, 11, which, by means of adjusting screws, bring them into more or less intimate contact with the rollers, 8, and consequently vary the charge of color at pleasure. The blanket, backcloth, and fabric are circulated as follows : — At the four angles formed by the three tables, b, are rollers, 1, armed on their surface with needle points, which pre- vent the cloths from slipping as they pass round, and thus secure the regular movement of the stuff to be primed, a movement determined by the toothed wheels, 21, {fg. 99,) fixed at the extremities of the axes of these rollers, g is a roller for stretching the endless web, resting with the two ends of its axes on two cushions forming the extremities of the screws, 12, by which the roller can be pushed further out when required, to give the cloth the neces- sary tension, n is another tension roller, supporting the blanket and backcloth. k is a roller which serves similar purposes for the blanket, the backcloth, and the fabric in course of being printed, t, the blanket, which in its course embraces the semicircumference of the roller, g, passes over the roller, n, and behind k, to circulate round the cylinders, 1, and over the surfaces of the tables, b. l is a cylinder from which the backcloth is unwoimd, being first stretched by the roller, n, and then smoothed by the scrimping bars, 13, from which it proceeds to join the blanket on arriving at the roller, k. m, a roller, from which the fabric to be printed is unrolled by the movement of the machine, first passing over the scrimping bars, 14, and joining at K the blanket and backcloth, which it accompanies in their course till it arrives at the roller, g, when it separates and passes off in the direction of the line, n, to the hanging rollers, where it is dried. The machine is put in movement, either by a man with a winch-handle, or by power communicated by a strap which passes over the pulley, 18. This pulley has several diameters, so as to give several speeds ; it is loose on the driving shaft, and carries catches CALICO PRINTING. 229 which lock into those of a sliding catch-box on the shaft, when the machine is to be put in movement. The movement of the machine is intermittent because the printing is inter- mittent ; moreover, it must be so regulated that the fabric advances a distance exactly equal to the breadth of the blocks, and that it moves forward whilst the sieves are charged with color from the rollers 8 8. Tliis result is obtained by means of a regulator, or dividing wheel 20. The wheels 21, fixed at the extremities of the axis of the cylinders 1, and havin"' each the same number of teeth, receive their movement from a central wheel toothed in the same manner, and placed behind the wheel 20. This last receives an alternating motion from a rack, 24, fixed in a copper piece, 25, and which rises and falls alternately, beino- keyed at its lower end to one of the spokes of the wheel 28. By varying the position of the point at which the end of the rack is connected with the spoke 26, the length or ran^e of its movement is proportionally changed, and more or less of the teeth of the wheel 20,°are made to pass, which renders proportionally, greater or less, the advance of the cloth at each movement ; and this is farther regulated by a ratchet wheel placed at d. At each half turn of this last, the lever 22 raises the catch or pallet, and throws out of gear the wheels 21 during the other half turn ; but as iu the working of these wheels there would be inevitably a backward movement, this is prevented by a brake, consisting of a pulley, mounted on the shaft of the axis of the wheel 20, and a brass wire, which, after making a turn and a half, or two turns, on this shaft, is stretched by the weight 23, which offers a sufficient resistance to any recoil. The slides or block-holders are put in motion by the wheels 27 and 28, gearing with the larger wheel 29. And to vary tlieir action at pleasure, both for causing the blocks to bear more or less strongly on the sieves, so as to be more or less charged with color, and likewise for attaining the exact pressure, which suits best for the color to be laid on, it is sufficient to move the points of junction, IG and 17, to a greater or less distance from the point marked 15, which constitutes the centre of oscillation of the beams that work the slides. The movement of the sieves is controlled by that of the cam 11, 30, which works them all three by putting in motion a shaft with which they are respectively keyed. The furnishing rollers receive their movement from gearing with pinions on the axes of the rollers 8 8. The general working of this complex machine remains to be described. When put into regular motion, and the three blocks have deliv- ered their impression exactly at the same instant, three simultaneous movements then com- mence. 1st. The stuff advances a distance exactly equal to the breadth of the blocks, and with it the blanket and backcloth, so that the portion of the fabric which leaves the third block behind it, is fully printed ; that which was under the second advances opposite the third ; that which was under the first, moves along to the second ; and a fresh breadth of white or imprinted fabric arrives opposite the first. 2d. While the cloth is advancing as above stated, the sieves take the place which they occupy in the section, fi/j. 98, that is to say, the first on the right hand rises, the second moves from left to right, the third descends, and in this movement all three press slightly on the furnishing rollers 8, from which they receive the color, which has been spread uniformly by the brushes 9. 3d. In the mean time, the slides, or blockholders, by a forward movement, push the blocks against the sieves, to charge them with color, and the blocks, at the same time, receive from the slides a gentle back- ward movement, during which the sieves deviate from their position ; the blocks then return upon them, and are drawn back again after being applied to a new part of the color sur- f\ice. When these simultaneous movements have taken place, the action of the machine proceeding without intermission, the sieves move back from before the blocks, and these are j)ushed up against the latter, printing the position of the fabric that is stretched upon them. Tills brings the machine to that position at which the description commenced ; and this suc- cession of movements is renewed and repeated as long as the operation lasts ; the printer having it always in his power to suspend the advance of the stuff whilst the working of the blocks and sieves continues, so that the color may be reappUed to the same part of the fabric as often as may be required for a good impression. There have been several attempts at block-printing by machinery in this country, amongst which the machines of Mr. Joseph Burch have been most successful ; but from one cause or another, none of them have ever come into general use, and it is unnecessary, therefore, to particularize them. Before proceeding to describe the more complex machines which print upon cloth several colors at one operation, by the rotation of so many cylinders or rollers, it is advisable to give some insight into the modern method of engraving the copper cylinders. These were formerly engraved altogether by hand, in the same manner, and with similar tools, as the ordinary copper-plate engravings, till the happy invention of Mr. Jacob Perkins, of America, for transferring engravings from one surface to another l)y means of steel roller dies, was with great judgment applied by Mr. Lockett to calico-printing, so long ago as the year 1808, before the first inventor came to Europe with the plan. The pattern is first reduced or increased in size to such a scale, that it will repeat eveidy over the roller to be engraved ; and as rollers are of varying diameters, owing to old patterns being turned off, &c., this 230 CALICO PRINTING. drawing to scale has to be adopted for every roller, the exact circumference of the roller being taken and the pattern arranged in accordance with this. This pattern is next engraved in intaglio on a roller of softened steel, which is of such a size that one repeat of the pattern exactly covers its surface ; generally these rollers are about 3 inches long, and from ^ an inch to 2 or 3 inches in diameter. The engraver aids his eye with a lens when employed at this delicate work. This roller is hardened by heating it to a cherry-red in an iron case containing pounded bone-ash, and then plunging it into cold water : its surface being pro- tected from oxidizement by a chalky paste. This hardened roller is put into a press of a peculiar construction, called the clamming machine, where, by a rotatory pressure, it trans- fers its designs to a similar roller in the soft state ; and as the former was in intaglio, the latter must be in relievo. This second roller being hardened, and placed in the engraving machine, is employed to engrave by indentation upon the full-sized copper cylinder the whole of its intended pattern. The first roller engraved by hand is called the die ; the sec- ond, obtained from it by a process like that of a milling tool, is called the mill. By this indentation and multiplication system, an engraved cylinder may be had for £1, which en- graved by hand would cost £5. The restoration of a worn-out cylinder becomes extremely easy in this way ; the mill being preserved, need merely be properly rolled over the copper surface again. The die roller is made of such a size that its circumference is exactly a frac- tional part of that of the mills, say one-half, one-third, one-fourth ; then in the clamming machine the die revolving in contact with the mill repeats its surface so many times on the surface of the mill. By this means as little skilled labor as possible is used. When a pattern having more than one color is to be engraved, the drawing is reduced to scale as before, each roller being made of the same diameter ; then a tracing is made of each color, which is en- graved on a separate die and mill — a mill being required for each color — which engraves its separate copper color ; when these rollers come to be worked in the printing machine, each roller fits its part of the pattern into place, and the original pattern is re- produced. The annexed drawings of engraving machinery are from those made by Messrs. Gadd and Hill, of Manchester, to whose courtesy are due also the drawings of the printing machines and their drying apparatus hereafter described. J'lff. 100 is a front view of the clamming machine, iiVidfc). 101 is a side view of the same. A A cast-iron framework ; b a head- stock screwed on the framework a ; c a sliding piece, capable of movement from back to front on the headstock B ; the position being determined, it is secured by the screw shown under c ; the roller d revolves in bearing .attached to the sliding piece c ; the supporting piece E has a motion backwards and forwards on the supporting piece o, which moves up or down ; c is a small sfecl roller, which again supports the die roller seen in the centre of the drawing. The roller f is of softened steel, called the mill, which revolves in bearings attached to the headstock, which has a sliding movement on the slide block n, which is moved from right to left by the screw, i, worked by the lever k. l is a pinion gearing into the toothed wheel n, and turned l)y the winch handle M ; the shaft p has a sliding movement through the wheel n, and carries the boss o, which has a square aperture to CALICO FEINTING. 231 receive the centre of the mill, which is squared to fit into it. y is a screw used to tighten and keep in the desired position the saddle pieces e o, which together are pushed up or down to meet the varying size of the die. The die d having been hardened, is inserted in the machine resting on the auxiliary hard steel roller e, which again rests on the supporting' piece e ; the die being in contact with the hard steel roller d, the soft steel roller or mill e is next forcibly screwed up in contact with the die, rotatory motion being given to the roller d by the toothed wheels ; those por- tions which are in intaglio in the die become in relief on the mill. It is then ready for the machine engraver to transfer its pattern to the copper roller. Fig. 102 is an elevation of the engraving machine a a is a mandrel which carries the copper roller b ; the mandrel IS fatted in the universal joint c, which is secured on the shaft of the wheels i d, which are a double pair of wheels for the purpose of altering the speed from fast to slow, and are moved by the winch handle or pulley. The lever e is fitted, works loosely on the shaft on which 13 keyed the wheel f. By means of the screw g, the lever e can be secured to'the wheel F. By this contrivance the motion termed rocking is effected, that kind of motion being required when the pattern repeats at great intervals. The mill works in bearin-s at- tached to the pil ar and carriage h h, which is moved from right to left by the screw^i i • t le mill IS forcibly pressed against the copper roller by a weighted lever, which forces down the bearings of the mill in the pillar h ; this lever cannot be shown in the figure but is at right angles to the roller. The mill being in contact with the copper roller, r°volves with it simultaneously on the roller being moved by the wheels d d or the lever e, and consequentlv impresses or engraves its pattern on the copper roller; when the mill has traversed the cir- cumference, It is then moved to its next relative position by the screw i, which moves the pillar and carnage h ; the exact distance the mill moves is determined^ by an index on the wheel K, which IS divided mto segments, corresponding with the number of repeats laterally on the roller The apparatus shown at l is used occasionally when the machine is employed for tiirning off an engraved pattern, which, however, is generally performed in a slide lathe and is unnecessary further to describe here. ' Etching by nitric acid is largely employed in engraving for calico printing, the following being the process :-The copper roller is first coated all oler with a thin coating of bitumi" nous varmsh, and when dry put in a machine which rules lines about the V3. of an inch apart all over the surface, the lines all running in one direction and diagonally to the axis the varnish being cut through by the ruling point. The pattern is then traced on in the usual manner. All the parts that are intended to be blank, are then painted in with the b. iiminous varnish by hand ; generally the outlines are put in bv skilled operatives the failing-in being done by girls or boys; when dry, the roller is immersed horizontallv in a bath ot diluted mtnc acid, and kept there for a few minutes, during which time the ac-id at- tacks and deepens the lines which are unprotected by varnish ; tlic roller is then removed well washed with water, and the varnish removed by oil of turpentine ; the pattern is found etched with diagonal bars, which in a good engraving should be nearly level with the blank parts ot the roller, the interstices being sufficient to supply the color. The outlines of the pattern are generally completed with the graver. This mode is well adapted for civin- a deep engraving, which is necessary for printing coarse fabrics. When a pattern is wwn down It IS easy to renew it, by simply painting up the blank parts and etching deeper by nitric acid. " * -^ 232 CALICO FEINTING. In 1854, William Rigby patented a mode of transferring patterns to copper rollers by a modification of the pentagraph. The pattern to be engraved being drawn on an enlarged scale, and put on a bed curved to an arc of a circle, a tracer being then moved over all the lines of the pattern by a beautiful, but simple, arrangement cf machinery, a tracer executed, on a varnished roller, a reduced copy of the pattern on the circvdar bed. In a patent, dated 1st January, 1867, Rigby introduced an improvement whereby any number of tracers could be simultaneously worked on the roller, by the simple movement of the tracer on the pat- tern ; thus all the repeats of the pattern could be executed at once. The mctliod is becom- ing very extensively adopted, and, independent of several large printers having begun en- graving on this system, a very large establishment, " The Burlington Engraving Company," has been commenced with a view to engrave on this principle. All descriptions of engrav- ing cannot, however, be done on this plan. The process is the following : — The pattern is first enlai-ged to five times its size : this is conveniently done by the camera. The paper pattern being put in the camera, an enlarged copy is thrown on a table in a darkened room, and is tliere easily traced on paper. It is then transferred to a thin zinc plate, and this plate is then engraved with a coarse graver, the lines of the engraving being adapted for the tracing point to work easily in. The zinc pattern, if of a two- or more colored pattern, is colored for the guidance of the operative. It is then laid on the curved bed of the pentagraph machine, and a varnished roller being mounted in the machine, a numl)er of tools, corresponding in number to the repeats laterally, and carrying diamond points, are placed in contact with the roller. The operative then carries the tracer suc- cessively into all the lines of the pattern, a lever allowing the points to touch the roller only when necessary. The pattern is thus traced by the etching points on the roller one- fifth of the size of that on the zinc plate, or the same size as the paper drawing. The roller is then painted and etched with nitric acid, as before described. A reference to the annexed engiavings will more clearly illustrate this system. In fiffs. 103 and 104, a represents the cylinder to be operated upon ; and 6, the bed or table for the reception of the enlarged pattern or original device ; c, the tracer, which is made to traverse in the direction of the arc of the bed or table, and by means of its connec- tion with the carriage h, the rail d, and the connecting arms e e, communicates part of a revolution to the bar or axis /, and thence to the cylinder through the dies g g, on which the cylinder rests. The cylinder being thus moved in a rotary direction, will receive from the tools in contact with it diminished copies of the transverse lines which may have been gone over by the tracer on the enlarged pattern or device. The tracer c being connected with the carriage, //, which travels along the rail d, will, in passing over a line running longitudinally witli the machine, communicate a partial revolution to the wheel I by means of the bands of steel _;' _/, similar to watch springs, which pass under and over the small wheels k k, and are passed round and secured to the large wheel I, which is mounted on the vertical shaft ??;, carrying at its upper end the small drum >«', round which passes the steel band «, secured at each end to the pieces o o. These pieces are secured by bolts or screws to the sliding frames p, to which the upper tool bar or bars q, which support the graving, drilling, or etching tools r r ?•, are fixed. Thus any motion of the large wheel I will be imparted to the drum m', and by it through the steel band n to the sliding frames p, and the tool bars q, and, consequently, to the tools r, thereby transferring to the cylin- der diminished copies of any lines in a lateral direction that may be gone over by the tracer. It will be evident that the result of the simultaneous action or compounding of the two mo- tions, by passing the tracer over any diagonal or curved line, will be the production of a diminished copy of such diagonal or curved line by each of the tools, s is a treadle with a vertical link and appropriate leverage, by which the tools may be brought in contact with the cylinder when required ; t t are counterbalance weights for the connecting arms e e, lower rail d, &c. ; u and v represent a worm and wheel for the purpose of giving the roller an extra partial revolution when it is required to engrave upon a different portion of the circumference of the cylinder ; and to effect a similar jmrpose in the longitudinal direc- tion, the tool bar may be made to shift in its sliding frame with an adjusting screw attached to it, by means of which any degree of exactitude in the setting of the tools may be ob- tained. In the machine, as shown in the accompanying drawings, the design executed on the cylinder would bear the same proportion in size to the enlarged pattern on the bed or table that the small drum m' bears to the large wheel I, and the radius of the disks g g, to the radius of the circular bed ; but by the adaptation of wheels and disks of different diameters, any desired proportion between the pattern engraved and the enlarged pattern may be adopted. In fg. 103, representing a mode of giving an alternate reverse action to the tools and bars a', are the bars, to one of which a longitudinal to-and-fro motion is given, and a reverse motion given at the same time to the other bar by means of the links or rods b\ connected to the beam or lever c', working on the pin or fulcrum d' attached to the framing e'. This arrangement of the machine is suitable for turnover patterns. CALICO PRINTING. 103 233 r ■^m^mm^mim^^xi^y^^^^^^ K /^ -s 234 CALICO PRINTING. 105 r©=i 1 •a' I^ ']\o)el In fffs. 106 and 107 the tool holders are adapted for employing two or more rows of tools, the members of the two rows being placed in alternate holders, or otherwise, accord- ing to the pattern. It is evident that by slight modifications in the form of the tool holders the tools may be made to occupy any position on the surface of the cylinder, thus affording great facility for placing the tools and making them applicable for step patterns or other suitable sketches. Figx. 106 and 107 show two such modifications, in which/' is the copper roller ; r/' the line of fulcrums or centres upon which the tool holders h' and k' vibrate, the said tool holders with their tools being lifted off by the cam I', and advanced to their work by the weights ?«', which can be adjusted with any required nicety. ^^Jlff^- 108 and 109 is shown another arrangement of tools with swivel bars, the swivel bars being shown at p', and placed and held in the desired position by the screws g'. To the bar is attached the carriage r, to one end of which is connected the tool holder s', in which is a projection t', acted upon by a beam or lever ti working on a fulcrum in the car- riage r . The tool is Hfted off the roller v' by means of the cam w', and returned to its work by means of a spring or Indian-rubber band x\ attached to the slide r'. It will be perceived that, independently of the slot or slide in the tool holder, great change of position is ol)tained by simply shifting the carriages longitudinally. The "eccentric engraving," or etching, of Mr. Lockett, of Manchester, produces on a varnished roller the most curious variety of configurations, by means of diamond points, moved by very elaborate machinery, the patterns being the result of eccentric movements given to the tracer by a combination of machinery. In this case the exact effect that will be produced by any given modification of the niachine cannot be determined, though an approximation can be made ; but when a pattern is produced, and notes taken of the rela- tive positions of the wheels, kc, the same pattern can at any time be reproduced. This system is applicable principally to groundworks, or, as they are termed, " covers." It is impossible in the scope of this article, to give a clear idea of this machine, as a very elabo- rate set of drawings would be required. With regard to the 2 and 3-colored machines, we mu.st observe, that as the calico in passing between the cylinders is stretched laterally from the central line of the web, the figures engraved upon the cylinders must be proportionally shortened, in their lateral di- mensions, especially for the first and second cylinder. CALICO PRINTING. 235 Cylinder printing, although a Scotch invention, has received its wonderful development in England, and does the greatest honor to this country. The economy of labor introduced by these machines is truly marvellous ; one of them, under the guidance of a man, to regu- late the rollers, and the service of two boys, to supply the color troughs, &c., being capable of printing as many pieces as nearly 200 men and boys could do with blocks. In mounting two or more cylinders in one frame, several adjustments become necessary. The first and most important is that which insures the correspondence between the parts of the figures in the successive printing rollers, for unless those of the second and subsequent engraved cylinders be accurately inserted into their respective places, a confused pattern would be produced upon the cloth as it advances round the pressure cylinder. Each cylinder must have a forward adjustment in the direction of rotation round its axis, so as to bring the patterns into correspondence with each other in the length of the piece ; and also a lateral or traverse adjustment in the line of its axis, to effect the correspondence of the figures across the piece ; and thus, by both together, each cylinder may be made to work symmetrically with its fellows. 110 Fig. 110 is an end elevation of a 4-color printing machine, and fig. Ill is a section of same : the same letters of reference refer to both, a is the cast-iron framework, bolted to a corresponding framework by the bolts b, with a space of from 3 to 4 feet between ; c is the pressure cylinder, about 2 feet diameter, of iron, but hollow, and between 3 and 4 feet long, according to the sort of cloth the machine is intended to print ; d are the copper roll- ers, the width of a piece of cloth ; e are wrought-iron mandrels, on which the copper roller is forced by a screw press, the mandrel being about 4 inches diameter where the roller fits on, but with journals of smaller diameter. Tiie roller is made with a projecting piece insie rollers being made when putting them in their places, the fine adjustment is made by turning the screw d. It is obvious that the screw d, by pressing against the lugs g of the shell a, which is geared into the driving wheel, will turn the mandrel and roller without moving the cogs. By this arrangement, any roller may be moved round about 2 inches at any time after being fixed in its place. All machines of more than one color are fitted with these wheels, which, indeed, are indispensable. In Jig. 113 is also shown a piece of apparatus attached to the framework for the purpose of cleaning the cloth from dust and threads before printing. This apparatus, patented by John Coates, of Manchester, is shown on an enlarged scale in fg. 115. It consists essen- 115 tially of a brush and a roller, covered with card or the wire material used in cotton-carding engines ; these, with the gearing, are attached by the straps of iron b n to the ends of the rods A A, care being taken that the roller o is placed parallel to the printing macliine, and the apparatus sufficiently high to be over the liead of the person engaged at work behind the machine, and convenient for him to reach out the roller and brush, when they require CALICO PRINTING. 239 cleaning. The piece passes over the small roller c, whether delivered from the " roll," or " beam," as at n or o ; it then goes under the wooden rail d, and over a brush e, and after- wards, at F, it comes on to the card roller, which is turned by the plain roller g (over which the piece passes) the contrary way to the piece, so that the card catches any loose material, and prevents it again adhering to the piece. Four five, and si.K-color machines, similar to the above, are now at work in many estab- lishments in Lancashire, which will turn off a piece of 28 yards per minute, each of the three or four cylinders applying its peculiar part of the pattern to the cloth as it passes along by ceaseless rotation of the unwearied wheels. At this rate, the astonishing length of one niile of many-colored web is printed with elegant flowers and other figures in an hour. When we call to mind how much knowledge and skill are involved in this process, we may fairly consider it as the greatest achievement of chemical and mechanical science. The general course of printing is thus performed : — The pieces to be printed are wound on a beam, and, last of all, a few yards of common coarse cotton or calico, kept for this purpose : this is for the printer to fit the pattern on, to save good cloth. The roll of cloth being put in its place behind the machine, the printer's assistant stations himself be- hind to guide the cloth evenly, and pluck off any loose threads he may see. The machine printer stands in front, and, after having fitted the pattern on the cloth, attends to supplying the color-boxes with color, and regulating any misfitting or inequality in the printing. The machine then prints rapidly. After running through 30 or 40 pieces, the printer stops the machine, removes the doctors, and files them anew to a bevelled sharp edge. To prevent the blanket being too soon soiled, it is usual to run gray or unbleached pieces between the blanket and the white pieces. The blanket, gray, and printed pieces are dried separately. There are several ways of drying after the machine. Ihefcf. 116 116 may be taken as representing a good and effective method. Behind the printing machines there is a hot room, in which is fixed the bulk of the drying apparatus. This room is kept closed, and is ventilated so as to let out the steam, &c. ; it is of necessity of much higher temperature than the printing apartment. Above the printing machine is fixed a frame- work, which carries the supports for the rolls of gray pieces, and a long range of steam chests, a a. These steam chests are the .same width as the machine, about 1 foot broad and 3 or 4 inches deep, and are connected one with another Ijy bent pipes at the end. The range of steam chests is continued through an aperture in the wall into the hot room, and below them is an arrangement of steam cylinders, turning on hollow axes, through which steam is admitted. The course of the blanket, gray, and piece, will be seen on reference to fiff. 116, in which the shortest arrow shows the course of the blanket, the longest arrow the course of the printed pieces, and the middle-sized one that of the gray pieces. The wliite pieces leave the roll 6, passing over a wooden roller, and thence round the cylinder along with the gray and the blanket. After receiving the impression, the piece passes over a small roller at the edge of the framework, and thence along the top of the steam chests, the roller being so regulated as to keep the pieces close to the chests, but not touching them. It passes along the straight length and flown the incline ; on leaving the chests, it passes round the cylinders Nos. 6, 5, and 4, being so .stretched by rollers as to embrace nearly the whole of the cylinders ; it then passes under the framework and up through an- other narrow aperture in the wall, being conducted through a plni.fi iiij-doini apparatus, which has drawing rollers at tlie end of a pair of arms, which move in a si'gment oi' ii circle, and so fold the piece backwards and forwards in a loose i)ilc. The gray and tlic lilankct, on leaving the cylinder, proceed together over a roller at the under side of the stciim chests, along which they travel as far as the roller r, where they part company, the l)lankt'ts pass- ing dowii over the cylinders 1 and 2, thence imder these cylinders and over and under the rollers d d, returning along under the steam chests rouiul rollers n c, and go again into the machine. The gray pieces, after leaving the roller c, pa.ss along the under side of the chests 240 CALICO PKINTmC. to the roller/, thence round the cylmder 3, the rollers g g, being finally wound on a beam at h. When the roll of gray pieces i is exhausted, the roll h is put in its place, the gray piec^es being run through the machine two or three times, according as they are more or less stained, and then sent to the bleach house. Scarcely any print works are without several 5 and 6-color printing machines, and the printers of goods intended for hangings, which are generally of elaborate floral designs, em- ploy machines capable of printing from 10 to 20 colors at once. These machines are neces- sarily of very large dimensions. Fig. 117 is an end view of a 20-color machine, made by Messrs. Gadd and Hill, of Manchester, for Mr. Kay, of Castleton Print Works, and is em- ployed in printing very beautiful floral patterns on woollen fabrics, in imitation of those produced by hand labor in France. The system of turning cylinder machines, patented by Mr. Joseph Leese, possesses several advantages. In this plan a small high-pressure oscillating engine is attached directly to the axis of the large cylinder, thereby dispensing with the heavy gearing and shafting required when machines are turned by a large stationary engine ; the machine print- er also has perfect command over the speed of the machine, and can fit the pattern, when it is turning very slowly, with more convenience than on the usual system. On this system also machines can be put down in any portion of the works, and are independent of the sta- tionary engine. In surface printing, the cylinder or roller is in relief, just as the wooden blocks used by hand, and the manner of working them is shown in fg. 118, which is the section of an 8- color surface machine of Gadd's. a a is the framework ; b b the bowl or cylinder, which is hollow, and made with arms inside ; c c are the surface rollers, supplied with color by the endless web or sieve //, revolving round the wooden tension rollers d d e ; the roller E is screwed down so as to press the sieve on the furnishing roller r, which revolves in the copper color box g ; the two tension rollers next to the surface roller move in slides, so that, by means of the screw }i, the sieve can be pressed against the surface roller ; on leav- ing the furnishing roller f, the sieve is wiped by the doctor i, screwed lightly against the sieve by the screw k. The printing roller being in relief, there is no necessity for the complicated arrangement of levers as in the ordinary machine, and consequently the surface machine is much more simple. It is only adapted for patterns of little delicacy, as the outlines are apt to be not well defined ; the colors, however, from being laid on the top of the cloth, are very rich, hence for woollen fabrics the surface machine is well adapted. CALICO PRINTING. 118 241 Pieces for printing by machine are stitched together end to end, -nhich is usually done by girls, but the use of stitching machines is rapidly becoming general, and probably will soon become universal. One of these machines, found advantageous, is shown in_^^. 119. 119 This machine was the invention of Charles Morey, in 1849. A pair of wheels are fitted with leaves on their peripheries, and gear into one another like cog-wheels. These wheels are mounted in suitable bearings fixed to a sole plate, and receive rotary motion by means of a winch-handle. The centre of the teeth of both wheels is cut away, so as to form a cir- cular groove between the two teeth which happen to be together. Opposite to this groove, and attached to the frame, there is a bracket which carries ii sliding piece, with a spiral spring wrapped around it. In the end of the sliding piece, which passes through the bracket, there is a receptacle for the eye end of a needle, the point of which rests in the groove formed by the wheel ; the needle is threaded, and the fabric to be stitched placed behind the wheels, to which rotary motion is coninumicatcd, whurcby the faljric is successively folded into undulations, which, as the operation proceeds, arc forced on the point of the needle ; when the needle is full, and the piece at the other side of the wheels, the needle is Vol. III.— 16 242 CALICO FEINTING. pushed back on the spring, removed from the machine, and the thread drawn through the pieces, which are then basted or stitched together. This is a very rapid mode of stitching ends of pieces together ; but where a number of pieces are stitched end to end for the pur- pose of being put through several operations without unstitching, a firmer description of stitching is required, and a machine, known as the American machine, and patented by Newton in 1853, is frequently used. This machine consists of an arrangement, whereby a bearded needle is employed for throwing a line of looped stitches into the fabric. The pieces are hung double on pins projecting from two circular racks, which move in grooves formed in the face of a circular frame. These racks are driven by pinions taking into their teeth, and thus the piece ends are passed under the action of the needle, which, hav- ing a quick reciprocating motion similar to that of the needles of stocking frames, and being in like manner supplied with thread, is passed backwards and forwards through the fabric, and thereby leaves a chain of loops on the inner face thereof. Carried by the same arm is a stiletto, which pierces holes in the fabric to allow of the needle passing freely through the same. The machine being rather elaborate, will be described in the article Sewing Machines. Pieces are also frequently gummed together at the ends, which is done by pasting the ends for about 1^ inches with paste or gum, and, after laying one on the other, drying them immediately on a steam pipe in front of the operator. This mode is advantageous for some purposes, as when the pieces come, in the subsequent operations, into hot water, they are easily detached one from the other. By whichever of these modes the pieces arc joined together, they are then wound in rolls of about 40 pieces by a machine called a candroy, which winds them on the wooden beam which fits in at the back of the printing machine ; the cloth during the operation of winding becomes stretched laterally quite smooth, by the aid of one or two grooved stretch- ing bars, a due degree of strain being kept on the piece by it passing under and over several plain wooden bars, and to the axis of the wooden beam which receives the pieces being sus- pended weights which keep it forcibly in contact with the wooden drum which turns it by friction. In this machine, the ends of the axis of the beam pass through slots, which 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 salts of copper, would be too corrosive on a steel doctor, and in this case doctors of a composition like brass are used. They arc filed to a bevelled edge, and require to be retouched with the file after printing from 10 to 80 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 im])ortant 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 uniforni in texture, thickness, and elasticity. If the blanket is uneven, it has the efl'ect 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 jjossess a great increase of strength. When made into blankets, they arc found to be more capable of resisting the severe strains of the print- ing process, and consecjuently many more pieces can be printed from them than from the old sort. They arc made by Mr. Kichard 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. 24^ general use ; but recently a mode of printing with gray or unbleached calico has come into use, which is very favorably spoken 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 on a beam for removal. There are, therefore, 5 layers of cloth under the white calico when printing, which give a sufficiently elastic bed for printing from ; and very delicate shapes can be got. Any given part of the gray cloth is 5 times uppermost on the pressure cylinder, and consequently 1 piece of gray cloth is used to print 5 pieces of white. Gutta percha pressure cylinders, or " bowls," have been suggested by Dalton, an English printer ; but, though theoretically preferable to iron, they do not appear to be much used. The proper hygrometric state of calico when printing should be attended to ; very dry calico does not take colors or 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," generally several hundred pieces in advance, and they easily absorb sufficient moisture from the air to be in a proper state for printing on. Pieces after printing 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 " ageing I'ooms," as they are called, are in several print works of enormous dimen- sions, and are 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 acetic 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 these 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 Thorn 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 speedily causes 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 tliat 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-pan.s 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 2U CALICO FEINTING. Manchester, is represented in Jip. 120. This range consists of 8 double-cased copper pans, containing from 1 to 28 gallons, riveted together at the top, wired at the edges, and made peifectly steam-tight ; they are supported on cast-iron pillars, and are so arranged or fitted as to swivel or turn over when the color is required to be emptied, by means of a brass stuffing box attached to pan, and working in the corresponding part attached to pillar on the one side, and moving at the other on a plain brass nozzle, 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 are 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 connect the steam and cold water pipes, as more fully explained hereafter. 122 123 120 f r-^ W- f fe W i? ^ mo iJaQ ^ :^ ~^ ^^fii. 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 m Jig. 121, marked /", the water passing through precisely in the same manner as the steam in a. n is the condense pipe, with one blank end and open at the other, with flange, underneath the pans, to carry off the water or steam, and is supplied with ground brass nozzles, 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 po.Htion and connection of steam and cold water pipes to bra-ss tap, the cold water pipe miming 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 th'i^ fig. 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 o])posite pillar, as further sho^\^l 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 these pans and stirred well all the time they are being boiled ; good stirring is very essential to produce smooth colors. This was formerly done by hand with a flat stick, but lately the best print works have been fitted with machinery over the pans to stir mechanically. A very effective plan of this sort is represented in Jigs. 124 and 125. It is that of Messrs. Mather and Piatt, of Manchester, the boilers in this drawing being not reversible, though the plan can be just as easily adapted to that descrip- 124 tion of pans. Fifi. 121 is a front elevation; fig. 125 is a transverse section, awAjig. 12G is a sectional plan, the same letters referring to all. a is a horizontal shaft above the pans, ft 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 stnall cuts) ; the catch box is worked by a lever handle d, and thus motion is given to the vertical shaft e. The shafts a and c are both supported by the framewoi-k /, fastened to the wall ; the shaft e is terminated by the frame g h r/, the centre of which, A, is a continuation of the shaft e \ and the wings g are hollow to carry the shafts ^•, which are surmounted by the cog wheels i i, which gear into a cog wheel / on the shaft e. The agitators n >i are made of flat brass rod, and are curved to fit the bottom ; they are connected with the shafts k k by a hook joint, which is steadied by the conical sliding ring m ; the agitators thus hang from the shaft e, 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 b.cing 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 246 CALICO PRINTING. 125 require the consistence of the thickening to be varied ; such as the nature of the mordant, its density, 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 arable 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 printing-on make blotted work. In France, this evil is readily 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 preferred, because it communicates more transpa- rency to the dyes, and because, in spite of the washing, more or less of the starch always sticks to the mordant. Gum has the inconvenience, however, of drying too speedily, and forming a hard crusrt 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. 5. (lum substitutes or soluble gums. 6. Gum Senegal. 7. Gum tragacantb. 8. Salcp. 9. Pipe-clay or china-clay mixed with gum Senegal. 10. Sulphate of lead. 11. Molasses. 12. Dextrine. 13. Albumen of eggs. 14. Lactarine. 1.5. Gluten. IG. Glue. CALICO PEINTING. 247 Those most used are the first seven. The rest are only adapted for special styles or colors. The artificial gums produced by roasting starch or farina are very largely in use. The action of heat on starch causes a modification in it. According to the degree of heat and its duration a greater or less modification ensues, the higher tlie heat, the more soluble in water the gum, but also the browner and of least thickening properties. The addition of various acids and alkalies to starch or farina before calcination, causes them to become soluble at lower temperatures than without ; different acids also produce dift'erent results ; those most generally used are nitric, acetic, muriatic, oxalic, and recently lactic acid has been proposed by Pochin. The proportion of acid used is very small, and, though the effect is produced, the acid disappears during calcination. Small quantities of alkahes are also used for special modifications of these gum substitutes. The making of these gums is a distinct branch of trade, and 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 thicliening to 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 inequalities in their tints. Sometimes the color is strong and decided in one part of the piece, while it is dull and meagre in another. The latter has been printed in too dry an atmosphere. 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 as to afford a ready outlet to the aqueous and acid exhalations. The cloth ought to be introduced 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 useful straining machine has been recently invented by Dollfus Mieg & Co., and patented in this country. This maciiine is shown in Jiff. 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 fiff. 127 is a side elevation of the said machine or apparatus, andjir/. 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 lo\ter part by the ring a. The skeleton plate b, which forms the bottom of the cylinder, is removable, and sustained by the four hooks c. To disengage the plate b, springs are fitted on the ring d, which act upon two of the hooks o, so as to throw them out from under the grid b. 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 f, g, n, 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/ 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 lowtr part of the frame p, and vice vcnsd. On the shaft x is placed a second wheel q, by whidi a reverse motion is obtained, and the piston m raised to its original position. Colors for printing by block are for the mo.st part thickened in the same manner as those for machine, l)ut are made thinner, since very thick color cannot be applied by block. Some substances also can be used in block printing that arc inapplicable to machine, such as pipe-clay and china-clay, which, however finely ground, still contain 248 CALICO PRINTING. 127 128 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 piint-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 woiks, the ((uality also being uniform and good. The printer now only makes for himself a i\;vf unimportant articles. 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 reciuired 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 dei)artment are : — Logwood liquor. Peachwood liquor. Sapan liquor. Quercitron bark liquor. Gall liquor. Persian berry liquor. Cocliineal liquor. J'ustic liquor Catechu liquor. Ammoniacal cochineal liquor. Extract of indijro. CALICO PRINTING. 249 And the various mordants and solutions are : — Red liquor, or acetate of alumina. Iron liquor, or acetate of iron. Buff liquor, or pyrolig- nite of iron. Pcrnitrate of iron. Permuriate of iron. Protomuriate of iron. Ammonia liquor. Acetic acid. Pyioligneous acid. Nitric acid. Muriatic acid. Sulphuric acid. Caustic soda liquor. Caustic potash liquor. Protochloride of tin in so- lution. Oxymuriate of tin in solu- tion. Nitrate of copper in solu- tion. Acetate of copper in solu- tion. Lime juice. Many other dry acids and salts are also kept in stock. For the constitution of the vari- ous mordants and their preparation see Mordants. ' It would be impossible to particularize all the styles of calico printing. The variety is infinite ; but they may be broadly classed as follows: — I. Madder styles, varieties of which are — a. The simplest 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 black, and brown from catechu being also introduced ; these are dyed with mad- der, the ground remaining white. b. Any or all of the above mordants, together with lime juice, technically termed acicl, printed, and 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 this 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 shade 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 madder and subjected to a peculiar clearing with soap, whereby pink shades of very great delicacy are obtained. All these are what are termed fa'^t colors, and having, after dyeing, undergone severe soaping, cannot be altered by the usual domestic washing process. II. The same styles are dyed with garanein instead of madder ; heavier and darker col- ors being employed. These goods are not soaped, garanein 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 Ijeing 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 vcith strong acid, or dis- chnrge 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 freiiuently relieved by steam-colors blocked in. v. Indigo-blue ; a style of considerable importance. In this, a resist paste, cither 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- 250 CALICO FEINTING. liar process fixing the indigo in the cloth, the result being blue figures on white ground. All indigo styles are fast or permanent. VII. Turkey-red and discharge. — On dyed Turkey-red cloth 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 acid colors, and discharges the red. The pigments or lead-salt being fixed in the cloth at the same time, after washing and chroming where yellow has to be obtained, the piece presents a pattern, bitten as it were in the Turkey-red ground. Black is also printed along with the other colors. A modification of this style is the well-known Bandanna style used for handkerchiefs. Turkey-red cloth is folded in a hydraulic press on a lead plate perforated with a pattern. When a sufficient number of folds are made on this plate, a precisely similar plate is put on the top, so as to register accurately with the bottom one ; pressure being now applied, the cloth is squeezed tightly between the two plates, a top being opened above the upper 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 pattern of the lead plates. VIII. Steam-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 whites 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 arc 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. X. Bronzes., formerly a style in large demand, but now almost obsolete ; done by pad- ding the cloth in solution of protochloride of manganese, precipitating the oxide by means 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 tlie 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. lied Liquor is the technical name of the pyrolignite of alumina used as mordant for red, &c. Iron Liqnor 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 tliis injurious tendency. The earliest fixing liquor used was a solution of arsenious acid ; and though other fixers have from time to time l)een introduced, the preparations of arsenic still hold their ground. A very good fixing litiuor, that has been much used in France and England, is made as follows : — CALICO FEINTING. 251 • ■^n ,u" ^''"'P^fi^^^U Liquor.— n gallons water, U gallons acetic acid 9 lbs sal ammo ""'"in isi^rrh ' m' ' '"^ 'f the arsenic.is dissolved, and let stand'till quite clear No. 2. To 100 lbs. potato starch, add 374 gallons water, 123 <^allons nitric acid snonifin gravity 1-3 and 4_oz. oxide of manganese. Th% chemical action wfuchake place 'an^'nS these mgredients is a lowed to proceed till the nitric acid is destroyed. To the reSm thus produced are added 50 gallons of pyroligneous acid, and the compound is he as ^"an mordant hquor m a fit state to add to the various mordants used in printing and dven" Tlie intention in making this liquor is to carry on the decomposition of the nitric acid and starch as ar as possible without forming oxalic acid, and as little as possible of carbonic acid which IS gently aided by the catalytic action of the oxide of manganese, preventin" the formation ot oxahc acid. Apparently there is formed by this process saccharic acid o°r an acid in a ow state of oxMation, which is the active agent in preventing the peroiidize- men of the iron when added to purple mordants. This'liquor has been fargel/used and ^ still preferred by some printers. Of late, various fixing liquors have been made and soM W?hr«'1"""Af '"'''''' ^y^f^r^'^'t'''''^ "^'^ ^'•^^"''^"^ ^^i^' ^' ^^s^^ite of soda form, ing the staple of them ; some of these have chlorate of potash added, the object be in- the formation of arseniate of ron when the cloth is dried: whereby the acetic'' acdi more speedily driven off ; and since arseniate of iron does not pass beyond a certain degree of ox.dizement in the air the mordant is kept in a proper state for dyeing good colors The following is also a good purple fixing liquor :— / s fe "" i-owrs. ine ^.'\' \P'ZP^^fi^i^9 Liquor.— BoW together till dissolved 2 gallons water 25 lbs soda heSed to Jo 'r ^'\T.r Tf T'^" ''"°'^^;*;' f^ '' '' S^''«- -ood add previoul; quarts muilL acid!'* ''''^' '" ' ''' "^ *"^° '''' ^''^ ''' '' *^^ -^'^ ^« -"^^d. -^ add I The following madder colors are from some in practical use, and though almost everv color-maker has different receipts for his colors, they may be taken to represent the general prmciples on which these colors are composed. f t ii^e geuerai 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 w ole strained. "' ^^ ""'^ «^ *^^^ double-cased steam-pans till quite smoolh rcooledr and No. 4. Black for Machine, {Madder.)— 4. gallons iron liquor at 24° T. 4 eaUons nvroli"-- neous acid, 4 gallons water, 24 lbs. flour; bofl, and add 1 pint oil ^•' ^S'^^o^spyiolig- T ^tJ,M^l"'''^7 f '^'■«T''' (^{^^^"'"^O-n gallons water, 3 gallons iron liquor uit 24° ' It* °^ ^ P,"''P'*' ^'''"" '"*"'"*' (^^•'- 3') 24 lbs. flour, 1 pint oil No" S" pZtl^i^7 ^\ft'' (/!^«^^,^.'*'^-)-12 gallons red liquor at 18° T., 24 lbs. flour, q with ^«^t t-(t ^f 'f''" (^^«^/"»'') are made by reducing the standard liquor No 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 the S of thickener""*''''"'' ^'^'"'-1*^ S^"«°« ^^t^^-' ^0 lbs. gum substitute, No. 5 in kA' n n I ' r'' I'']'} '',^.'" ""'^''^y ^^l'^ ^'JJ 12 lbs. of mudate of tin crvstals. Ao. 11. JJark resi.sf.red Machine.-S^mc as No. 10, but 6 lbs. of tin crystals'onlv when it ha7to7J'f' ^'^ 'f '' ""''"^ ''^'''' '' ^'^^ *« '''''' ^ chocolate coAr, and No. 11 wnen it nas to resist a purple cover. watfr^'aiLwS^onTn'^t'^V^''-^^ (^/«/«-ne.)-Made by reducing resist-red liquor with T ? IhTflo h.M° 1 ^ ,'■ "f""*"'' .^"- ^' P^^''^-''^'^= 12 gallons resist-red liqtior at 5° 1., y lbs. flour; boil, and add, when cool, 2 lbs. tin crystals is -1 mnhM^nr/,"''"' '"■'' ™'^^^/™.'^ "•«» I'quor and red liquor mixed, and the red liquor on ruo?at 24° t'q'" ',]''' ^^'^ /."^'ance, 3 chocolate (madder) (machine) :-3 gallons Ze VLu ■ V gallons red liquor at 18° T., 24 lbs. flour, 1 pint oil. No. GChoco- X^ if ^/ "■"'' Tf' ^ ^* ^•' ^ S^"«"" ""^ ''^l"""- at 1«° T., 14 lbs. flour, 4 pint oil. water°'24 ibffloS -^'''' ^'''''''''''''^ (^/«cAe«c.)_ 10 gallons red liquor at 18° T.,''2 gallons flnnf.Vii ^'''■f-'"=^fo\(^arancin, (J/«eA»*«.)_l 2 gallons resist-red liquor at 14° T., 24 lbs. flour; boil, cool and add 9 lbs. tin crystals. This for resisting chocolate. fl./VV ;■'''fA^^'''"^''*'''(^'^'^'•'''''''^•)—12Kallons resist-red liquor at 14° T 24 lbs flour ; boil, cool, and add 4^ lbs. tin crystal.s. This for resisting purpli. ' H n i 1.1 T' '^^«";^««^/'»- Madder. -r^O gallons water, 200 lbs catechu • boil 6 hours then add \\ gallons acetic acid, and add water to make ui, to 50 gallons- take ou and let stand 36 hours, and decant the clear; heat it to 130^ R, md a.lic/- inr/ ; 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, i\ feet wide, i>:\>\\. .\.,«:s\^ Up to this point there is scarcely any difference in the operations on pieces destined for styles 1 a, b, &;c., and 2. Those intended for dyeing with madder are printed in stronger ^colors than those for dyeing with garancin, since the soaping process reduces the strength of color considerably, and garancin colors undergo no severe treatment after dyeing. The general process of dyeing is thus performed : — Fig. 135 represents a front elevation of a pair of dye becks, with automatic winch reel, and_/?V/. 136 is an end elevation of one of them. The drawing is kindly supplied by Messrs. Mather and Piatt, of Salford. a a is a cast-iron cistern, 8 feet long by 4 feet deep by 3 feet wide, with curved bottom ; brackets b b are cast on the ends to support the cistern on ir;.3 CALICO PRINTING. 261 136 the stone foundation. The beck is fixed over a channel c, which commxinicates with the system of drains which carry away the waste liquors into the river. There are two holes in the curved bottom — one at each end — which, when the beck is in use, are stopped with movable plugs ; one of these holes communicates direct with the drain and the other with a trough D, which communicates with a pit out- side the dye-house, and where the spent madder can be run for the purpose of making into garan- ceux. E is a water pipe, with a branch into each beck, with a screw tap attached ; f is a main steam pipe, which divides into 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, the perforated pipe k, which traverses the beck from end to end, con- necting them ; a perforated 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 projecting at right angles from it. Bolted on the ends of the dye beck is the frame- work o, which carries the bearings of the shaft Q of the wincli reel ; keyed on the shaft are three sets of cast-iron arms r, which terminate in forks, in which fit the spars s ; the reel is boarded between the spars, as at t. The frame- work of the two dye becks is connected by the piece u, which carries the bearings of the short shaft v, on which is keyed one of a pair of mitre wheels w w ; there are sliding catch boxes s 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 carries also the pillar p, which carries the bear- ings of the vertical shafts y, and also of the horizontal shaft z ; keyed on the shafts Y and z are bevel wheels a a, and at the bottom of shaft t, the mitre wheel w. Permanent motion being given the shaft v v, by this gearing, either of the reels can be put in motion or stopped by the catch boxes x x, worked by lever bandies, 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 w-eb, 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 wliich soap plays a principal part. Garancined goods show pretty nearly the color they arc intended to be ; but as tlie white is ako stained, a peculiar clearing is given them \\hich 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 J to + lb. of SDap 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 purjjle in the ))at- tern, some sumac, which is found to economize madder, t)ut will not do where there is pur- ple, the shade of which it deadens. Pieces of any style, after undergoing the final proces.'s, 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 ar(^hen dried on the cylinder drying machine. 262 CALICO FEINTING. Plate Purple is a style composed of black and one or more shades of purple only, and requires a little different treatment. Print in black No. 4, dark purple to shade No. 27 and acid, say No. 35, cover pad in pale purple, No. 30, age. Fly dung at 170° F., second dung at 105° F. half an hour; wash and dye with ground Turkey madder root, giving '/io of its weight in chalk, and 3 quarts of bone size to the beck ; 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 wince 5 minutes at 140° F. with 2 quarts chloride of lime liquor at 8° F. to 300 gallons ; wince and soap again at boil half an hour with 3 lbs. soap to 15 pieces ; wash and wince 5 minutes in 4 quarts chloride of lime at 8° F. and 2 lbs. carbonate of soda crystals to 200 gallons water ; at 160° F. well wash and dry. In this style, as in any where there is severe soaping, it is necessary 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 few, and frequently only different shades of one color. Plate Pinks or Swiss Phiks — a style imported from Switzerland, consisting of various shades of red and delicate pinks, produced as follows : — Print in No. 6 with 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 1G0° F. — if dung substitute is used, care must 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 -J cloth, from 4 to 6 lbs. of French madder will be required. About 5 i)er cent, of chalk may be added to the dye where the water is soft. The heat should be i-aised 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 cuttinc/, 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. Afttr 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 1C0° 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 inipovcrish 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 Maddk.r) 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 FEINTING. . 263 used for full heavy colors, which, if dyed with madder and eoaped, would be, to a certain extent, abraded, and not stand so finely on the^surface of the cloth. Chocolate grounds, black, red, and chocolate, with brown or drab, dark purple plates, black and scarlet ground, are thus dyed ; in short, wherever 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 madder, (see the list of colors,) the ageing and dunging, &c. are the same as for madder ; the dyeing is performed in the same manner, using from one- fourth to one-third the quantity that would be used of madder. A little chalk is also added where the water is soft ; and the dyeing is commenced at 110° F., and carried to 185" F., or 190' F. in two hours ; then got out and well washed and rinsed in water at 140° F., in a beck, for 10 minutes, then squeezed and dried. The white is always stained a little, though not to the same extent as in maddered goods, and this slight stain is removed by a process peculiar to garancin goods. In front of an ordinary cylinder drying machine, is placed a padding apparatus, and between it and the drying machine is placed a chest provided with a few rollers at top and bottom ; this chest is covered by a lid, which has at each end a slit, by which the piece enters and issues ; a perforated steam pipe at the bottom of the chest allows steam to blow 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 white ; 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 i 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, they proceed on to the cylinders of the drying machine, on leaving which the white is found 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 well, and this class of goods is usually dyed with chocolate garancin, assisted by small quan- tities of sumac, quercitron bark, and peachwood, which additions give full rich shades. Where there is purple, none of these adjuncts can be used, and the garancin requires to be made from a superior description of madder. Within the lust three or four years, great im- provements in the manufacture of purple garancins have been made. The Alizarin, patented by 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 wh^n these colors are freely introduced along with purple, an admixture of ordinary purple garancin is required, the general effect 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 making 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 ciuantity of acid, proportionate to the quantity of madder, is allowed to run down through the per- forated bottom and mix with the hot li(]uor ; the acidulated li(|uor then i-uns 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- 264 CALICO FEINTING. tages of this plan are, first, the saving of fuel, by economizing the heat of the waste liquor, and, secondly, the production of one-lourfli more coloring matter. Tliird Style : Reserved. Maddered or garancined goods are often left with white spots, as leaves, &c., and when dved these spaces are filled with various bright colors, such as green, blue, yellow, &c. These colors are the ordinary steam colors, described hereafter, and are fixed in the same manner. Another way of combining madder or garancin colors with steam colors, is by blocking on the dyed object, generally groups of flowers, a reserved paste, (No. 39,) and when this is dry, covcritiff by machine in small patterns with various shades of drab, olive, &c., (Nos. 5, 44, 46, &c.,) which then are dunged and dyed with quercitron bark, cochineal, madder, and bark, kc, &c. Where the paste has been applied, the colors underneath, or the white spots reserved, are unafl'ected by the covering color, and stand out clear surrounded by the cov- ering color. In the white spaces reserved are now blocked steam colors, 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 or iron liquor, or mixtures of them, drying in the padding flue ; then a pattern is printed on in acid, and the usual dunging and dyeing operations performed, the result being a dyed ground with a white pattern. Fiff. 137 represents a section of the padding flue used in mordanting to this style. 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, f 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 _;, which is connected with sliding doors over the apertures, kk are oast-iron supports for turned copper rollers, which are fixed to the cross pieces y y, and serve to conduct the piece. 1 1 are bars of iron which carry the fans rn in, 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 CALICO PRINTING. 265 the bottom of the slot working in brass bearings ; a weighted lever presses the top roller iu forcible contact with the others. Padded goods, after printing in acid, are hung 2 or 3 days in the ageing room, dunged, and dyed. A few of these shades are here given : — a. Caret and lohife. — Pad in red liquor at 10^ F., dry, cool, and pad again in same liquor, dry, cool, and print in acid No. 37, age 3 nights. Fly dung at boil, wash, second dung at IGO' F., * hour, wash, dry, and sinffc, wash and dye 12 pieces 7 ft. 8 in. 30 yards with 18 lbs. ground peachwood, 21 lbs. of t>ench madder, 6 lbs. sumac, 5 lbs. prepared log- wood, run the pieces in the beck cold for 20 minutes, and then bring to a boil in 1 hour and 10 minutes, boil 1.5 minutes, get out, rinse and wash, bran 10 minutes at boil in a bock with a i'ew pounds of bran, rinse in a pit and bran again at boil, wash and dry. Prepared Logwood is thus male. — Grountl logwood is spread out on a floor, damped with water, and heaped up. It is then turned over once a day for a fortnight, and occa- sionally wetted, during which time it changes from a dull red to a bright scarlet. It is then ready for use. Some change, probably oxidation, has taken place, and the wood dyes fur- ther after this process. b. Scarlet and white. — 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 size ; 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 red 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. Burgnndy and white. — Pad, &c., as for clarets; dye 10 pieces with 18 11)S. French madder, 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 logwood, 5 lbs. Dutch crop madder, and 7 lbs. peachwood, 2 lbs. bran, and 3 quarts bone size. Bring to boil in 1| hours, boil a quarter of an hour, wash and bran 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 cochineal, 1 lb. ground galls, 4 lbs. prepared logwood, 3 lbs. peachwood, heat to 170° in 1 hour and 20 minutes, keep at 170^ 10 minutes, wash, bran at 160' 10 minutes; wash and dry. ff. Amber and white. — Pad, &c., as for clarets ; dye 10 pieces with 20 lbs. quercitnm 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 1:^ 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, ago 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, d'c., 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. /. Bark dyeing. — Dye 10 pieces with 25 lbs. bark, and 3 quarts bone size ; heat to 190" in 1| 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. i)reparcd log\yood, 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 arc 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. Th.'rc are about 10 vats in a row. A. Blue and white. — The simplest form of blue styles is lihie and white ; dark blue * ground with white figures. The cloth is ])rinted in one of the following reserve pastes : — No 65. lienerve paste for Block. — 3 lbs. sulphate of copper, dissolved in 1 gallon of water, 15 lbs pipe-clay, heat up with some of the licpior ; 1 gallon of thick gum Senegal so- lution, and 1 (}uart of nitrate of copper at 80" T. 266 CALICO FEINTING. No. 66. Reserve paste for Machine. — ih lbs. sulphate of copper, 1 gallon of water, thickened with 9 lbs. flour, and 2 lbs. dark British gum. No. (u. 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 lbs. flour and 2 lbs. pale British gum'; when cold, add half a pint of nitrate of copper at 80° T., to every 2 gallons of color. No. 08. Reserve paste for Machine. — 4 gallons boiling water, IG lbs. of sulphate of copper, 8 lbs. white acetate of lead, let settle and pour oft" the clear liquor ; thicken 3 gal- lons of this with 8 lbs. of flour, and 4 lbs. pale» British gum. When boiled, add 4 lbs. sul- phate of zinc, and dissolve. The foregoing are all to resist deep shades of blue, for light shades of blue dipping any of the following : — No. 09. Mild paste for Block. — 25 lbs. dark British gum, 15 quarts of water, boil 10 minutes, and add 74 lbs. soft soap ; stir well in, and, when mixed, add 20 lbs. sulphate of zinc, stir well in, and add 10 lbs. pipe-clay, beaten up into Vi quarts of water, and 7^ gills of nitrate of copper at SO' 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 G 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. Iiuligo 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 line : 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 water, 250 lbs. of hydrate 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, and 170 lbs. lime; dissolve the copperas in the water, then add the indigo, stir well up, and add the lime, previously riddled to separate small stones. Rake up every two hours lor two davs, and let settle clear. The clear liquor, when taken up in a glass, must have a deep veilow 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, apd 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 arrangi-mcnt 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 fre.sh vats with. n. Blue and Yellow, or Orange. — Print in one of the reserve pastes, and yellow or orange color made as follows : — No. 71. Chrome yclloiv for Machine. — 2 gallons water, 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. white 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 veilow color. CALICO FEINTING. 207 Follow the same routine in dipping, &c., as for blue and white. After wincing in sul- phuric acid sours, wash well, and wince 10 minutes in bichromate of potash solution, 2 oz. per gallon at lUO' V. Wash well, and wince in dilute muriatic acid at V T. containing 1 oz. oxalic acid per gallon, till the }-ellow is quite bright. The small quantity of chromic acid set free oxidizes and destroj^s the indigo that may be attached to the yellow color. After this souring, wash and dry. If orange was printed instead 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 lime to make slightly milky ; heat to 180" F., and wince the pieces in till the orange is full and bright ; then take out, and wash well, and dry. Other varieties of blue dyeing are : — c. Two blues. D. Two blues and white. E. Two blues, white, and yellow or orange. F. Dark blue and green. G. Two blues and yellow. For c and k a pale shade of blue is first given the cloth. The light blue vat is thus composed : — (Xo. 3.) Liffht Blue Vat. — 1,000 gallons water, 40 lbs. indigo, 10 lbs. copperas, 80 lbs. lime. For c. Dip light blue by three immersioiis, drawing well between ; unhook, wince in water, then in sulphuric sours at 2" T. ; wash, squeeze, and dry ; then print on a reserve paste, and 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. For D. On white cloth print a nobject in muriate of manganese, thickened with dark British gum, raise this as described under the head Bronzes, dry and block in a reserve paste Xo. 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 liquor has been added, wash and dry ; where the peroxide of manganese has been is now dark blue, the ground pale blue with white object. For K. Print as d, with yellow or orange in addition, and after the sulphuric sours, raise yellow or orange as before. Dip light blue, print reserve paste and yellow, dip dark blue, wince, sour in sulphuric sours 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. Xeutrals 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 : Xo. 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. X^o. 74. Chocolate, {Machine.) — 5 quarts red liquor at 12^ T., 1 quart iron liquor at 24° T., 1| lbs. sulphate of copper, 24 oz. measure of nitrate of copper at 100° T., thicken with 2\ lbs. flour, and h 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-day beat up well, and add 3 quarts of gum Senegal solution at 5 lbs. per gallon. Xo. 76. Dark Resist Red, {Block.) — 2 quarts red liquor 22° T., 5Joz. white acetate of lead, 4^^ oz. sulphate of copper, dissolve, and beat up in it 6| lbs. piiie-clay. Thicken sepa- rately 2 quarts red lic[Uor at 12° T., with 12 oz. flour, and add, when boiling hot,' 8 oz. of soft soap melted ; mix well, add tiie pipe-clay mixture to this, and then 2 (juarts red liquor at 2° T., thickened by dissolving gum Senegal in it. Stir the whole well together. Xo. 77. Dark resist Red, {Machi7ie.) — 20 quarts nitrate of zinc at 36 B., 10 (juarts water colored with a little peachwood, 12i lbs. alum, 10 li)s. acetate of lead ; dissolve all together with heat, stir till cool, thicken all together with 8 ll)s. fl<)\n', and li 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 Xo. 8 reduced with water, according to the shade wanted. 2G8 CALICO PKINTING. No. 79. Any shade of pale red for machine is made by reducing the quantities of alum and acetate of lead in color No. 77. The white reserve for this variety of neutrals is either of the mild pastes. No. 80. liesist Brown. — 2 gallons water, 24 lbs. catechu, 6 lbs. sal ammoniac, 1 gallon acetic acid ; boil 15 miuutes, and add 7.7 gallons gum solution, 5 quarts nitrate of copper at lUU^ T. Proccxx. — The colors after printing are aged 3 days, then dipped light blue in the fol- lowing blue vat. (No. 4.) Neutral vat. — 1,000 gallons water, 120 lbs. indigo, 135 lbs. copperas, 150 lbs. lime ; rake up for two days, and let .settle. A I'ranie with rollers toj) and bottom is lowered into this, and the pieces are run through ; after leaving the vat, they are made to travel over rollers in the air for a sufficient distance to turn them blue ; then into a pit of water, from that into a beck with cow dung and water, at 160" l'\, where they run 15 minutes, then washed and dyed madder or garan- cin, &c. &c. In the second variety of neutrals, the white is required to resist both mordants and blue, and is made thus : — No. 81. Neutral White for Blocks. — 7 quarts lime juice at 30° T., 1 quart water, 4^ lbs. suljiliate of copper, 24 lbs. pipe-clay, 3^ quarts lime juice at 30° T., previously thickened with gum Senegal. ' No. 82. Neutral WIdte for Mncfiine. — 1 gallon lime juice at 42° T., 2 lbs. sulphate of copper, 32 oz. measure nitrate of copper at 100" T., thickened with 1^ lbs. starch. The black is the ordinary madder or garancin black, Nos. 4 and 5 process. 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 with 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 colors arc generally blocked in. Parts of the yellow being made to fall over the blue form gi-een. Sixth S'ylc : China Blues. China bines, 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 IS lbs. copperas, the whole ground till quite fine ; then add 7i 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 f/iwi. — 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. Vov instance, for two blues of medium shades : — No. 85. Strouff Blue. — 1 volume standard, 2 volumes gum. No. 80. J'ale Bine. — 1 volume standard, 10 volumes gum. After printing, age one night, and raise as follows : — Two vats similar to indigo vats arc 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 and 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 jiut beams, on which the pieces are wound alternately ; the bear- ings of the beams l)eing just above the surfjicc 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 arc slowly wound througli 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 imd 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 copi)crasing is continued till the pieces have Ik en 4 times through each vat; tluMi detach and wince in water ; then ])Ut into sulj)huric sours at 10' T., immersing completely in the liiiuor till the whites appear (juite clear ; then wa.sli well, soap in a beck at 120' F. a quarter of an hour with a ^ lb. soap per piece ; wash again and sour in sulphuric sours at 1° T. at 11<>' F. ; wash well and dry. The various phenomena which occur in tlie dipping of China blues are not difficult of CALICO FEINTING. 269 explanation with the lights of modern chemistry. We have, on the one hand, indigo and sulphate of iron alternately applied to the clotli ; by dipping it into the lime, the blue is de- oxidized, because a film of the sulphate of iron is decomposed, and protoxide of iron comes forth to seize the oxygen of the indigo, to make it yellow-green, and soluble at the same time in lime water. Then, it penetrates into the heart of the fibres, and, on exposure to air, absorbs oxygen, so as to become insoluble, and fixed within their pores. On dipping the calico into tlie second vat of sulphate of iron, a layer of oxide is formed upon its whole sur- face, which oxide exercises an action only upon those parts that are covered with indigo, and deoxidizes a portion of it ; thus 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 deoxidizement, solution, and re-oxidizement recurs ; causing a progres- sively increasing fixation of indigo within the fibres of the cotton. Other indigo stylos are dipped greens, blue with white discharge. Dipped Greens. — There are 4 vats similar to indigo vats in a row, set with : — First: (No. 5.) Light 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 ■Grec7is.— 1,000 gallons water, 250 lbs. brown acetate of lead, 130 lbs. dry slaked lime ; rake up tUl dissolved, and let settle clear. Third : (No. 7.) Filled with water only. Fourth : (No. 8.) Set with bichromate of potash at 4° T. Each of 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 and fastened to a drawing roller at the end of the fourth, the pieces are drawn slowly thorough between the first and second ; the cloth is made to travel several yards, so as to injure 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, 70 ; 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 and acid No. 4, green, when the Burgundy part comes out a beautiful chocolate, and the white part green. Acid Discharge on Bine. — 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. 87. 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, 1\ 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 water, 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 lied 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.—I gallons logwood liquor at 8° T., 1 gallon i)yr()ligno- ous acid, 10 lbs. starch ; boil and add 2 lbs. 10 oz. copperas ; boil again and cool, then add 3,V 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. {!>) 4 lbs. prussiate of potash, 1 gallon of water ; dissolve. Mix a and b together, and add 1 quart standard red liquor No. 8, 1 quart nitric acid 60' T. No. 92. Yelloio Discharge, (Block.)— \ 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 l4 lbs. starch, instead of the pipe-clay and gum. 270 CALICO PRINTING. No. 94. Yellow Discharge, {Macldiic.) — 1 gallon lime juice at 40° T., 4J- lbs. tartaric acid 5 lbs. white acetate of lead, 1 J lbs. starch ; boil and cool, then add 1 lb. 14 oz. nitric acid, at 60°. No. 95. Blue Discharge, {Machine.) — (a) 1 lb. Prussian blue, 1 lb. oxalic acid, 1 quart hot water ; grind well together, and leave to react on each other 24 hours ; then (6) 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.) — U gallons No. 95 blue, 1 gallon No. 94 yellow. Process: — Print in any of the above colors, and as soon as dry from the machine, put through the decoloring vat. (No. 9.) Decoloring Vat. — 1,000 gallons water, 1,000 lbs. chloride of lime; rake well up, till quite smooth and free from lumps, then immerse a frame 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 leaving 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 bv passing through chloride of lime, whilst in the parts printed in the discharge colors, an instantaneous disengagement of chlorine takes place, which decoJorizes the dyed ground, and where a mineral color or mordant formed part of the discharge, it is left in place of the red dye. This style was invented in 1811 by M. D. Ka?chlin, and patented in 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 : Steajn Colors. The printing of steam celors 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, &e., before lively and substantial colors 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 H" 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, {3Iachine.) — 1 gallon logwood liquor at 12° T., 1 quart gall liquor at 9' T., •! 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 li(|uor at 12° T., 1 gallon nitrate of alumina, -J- gallon bark liquor at 12° T., 4 gallons water, 17 lbs. starch; boil, and add 8 oz. chlorate of potash, 21 lbs. red prussiate. No. 99. Dark Blue, {Machine.) — 7 gallons water, 14 lbs. starch, 2f lbs. sal ammoniac; lioil, 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 lierry 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 crj'stals. No. li»2. Orange. — 12 lbs. annatto, 1 gallon caustic soda at 70° T., 5 gallons water ; I CALICO PRINTING. 271 boil 20 minutes, strain, and add 3 quarts red mordant No. 146, 6 lbs. alum ; heat till clear, and add 4 gallons thick gum-substitute water. No. 103. Tin Pulp. — To protochloride of tin solution add as much yellow prussiatc of potash in solution as will precipitate all the tin as ferroprussiate ; this is washed by decan- tation, and filtered to a stiff paste. No. 104. Light Blue for Machine. — 1 gallon dark blue No. 99, 3 gallons 4-lb. gum- substitute water. No. 105. Green., {Machine.) — 7 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. nmriate-of-tin crystals, 2 lbs. oxalic acid. No. 106. Fink., {Machine.) — 4 gallons cochineal liquor at 6° T., 2 lbs. alum, 2 lbs. bitar- trate of potash, 8 oz. o.xalic acid, 4 gallons thick gum-Senegal water. No. 107. Purple, {Machine.) — 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 instead of 8 gallons. No. 108. Dark Red, {3fnchine.) — 8 quarts Sapan liquor at 12° T., 2 quarts bark liquor at 8° T., 2 quarts nitrate of alumina No. 109, G^- lbs. starch, 1 lb. gum-substitute, 4 quarts water, 4 oz. chlorate of potash, 12 oz. alum. No. 109. Nitrate of Alumina. — S gallons boiling water, 24 lbs. nitrate-of-lcad crystals, 24 lbs. alum, 5 lbs. carbonate-of-soda crystals ; let settle, and use the clear. No. 110. 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. Lai'cnder Liquor — 2 gallons red liquor at 18° T., 6 lbs. ground logwood ; let steep for 48 hours, then strain off the liquor. No. 112. Lavender. — 4 gallons lavender liquor No. 111,4 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 gallon bark liquor at 12° T., reduced same as drab. No. 115. Sar/e 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., \k quarts logwood liquor at 12° T., 12 quarts S-lb gum-substitute water, 3^1- lbs. alum, 2 oz. chlorate of potash, 5 oz. red prussiate. All shades of light browns arc made from this by reducing with gum-substitute water, according to shade wanted. No. 118. Ye'.low. — 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; iu 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 fiae and free from floeculent 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 exti-act 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 cliest. The column is a hollow cylinder of copper, from 3 to 5 inches in diameter, and about 44 inches long, perforated over its whole surf\ice with holes of about Vie of an inch, placed about \ 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 cntt ni 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 maybe let ofi"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 272 CALICO FEINTING. white calico, next with the several pieces of the printed goods, stitched endwise, and lastly, with an outward mantle of white calico. In the course of the 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 of the methods above described. The steaming lasts for 20 or 30 minutes, according to the nature of the dyes ; those which contain much solution of tin admit of less steaming. Whenever the steam is shut off, the goods must be immediately uncoiled, to prevent the chance 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. The other method of steaming, and the one now most generally employed, is that of the chest. This is a rectangular iron chamber, with penthouse top ; its dimensions are about 12 feet in length by 6 feet in width, by 9 feet in height at the highest 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 as the room in which the steam chest stands ; underneath the false bottom is a perforated pipe, running round three sides of the chest ; this pipe admits the steam, which is furtlier diHuscd 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 the chest for about 3 feet being hinged so as to be moved on one side when the doors are opened or shut. Upon the rails moves a rectangular frame of wood, which just fits inside the chest, and 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 piece is then slid oif 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 the 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 45 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 hikes 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 drkil, 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 works 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 l)y 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-off 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 Thorn, and is here shown : — TJionCs Sulphurinr/ Appnratns. — Fir/. 138. A is the roof, made of sheet lead, 4 lbs. to the foot, n is a lead pipe, of one inch diameter, t'aking off the excess of sulphurous acid to the flue, c and c are rolls of pieces, going in on one side and coming oft" at the other, d CALICO PKINTING. 273 and D, rollers of wood, three inches in diameter, with iron centres at the ends, e and e, tiles, as in malt kilns, to let the gas pass up through to the cloth. 138 Fir/. 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, f 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. Stdpkomuriale 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 roller^ 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. in"-, pad through gum-Senegal water at 8 oz. to the gallon, and dry. After printing, they are hun'' the same as calicoes to equalize the temperature, then hung in the steam chest in the same manner as calicoes, and steamed 45 minutes. After steaming, they are unrolled and loosely folded for washing-off, which is done by wincing over a reel in a pit of water gently for J of an hour, then transferred to a washing machine 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 advantageous 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. Tlie wool in mousseline de laines is apt to be par- tially decomposed during steaming, and sulphuretted hydrogen liberated, which decomposes the metallic salts, such as nitrate of copper, used in some colors, and produces a very di.sa- greeable effect, termed silvering. To avoid this, it is now customary to wind on the reel for steaming, at the same time as tlie printed piece, a gray or unbleached piece, which has been padded in a weak solution of acetate of lead, and dried. By this means the printed piece is steamed in contact with the prepared piece, and any sulphuretted 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. starch ; boil, and when cooled to 180' F., add IJ lbs. oxalic acid, and when this is dissolved, IJ lbs. rauriate-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 5f lbs. alum, 12 oz. chlorate of potash, 41 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 1} lbs. muriate-of-tin crj'stals. No. 125. Bark or Royal Blue. — 6 gallons water, 6| lbs. starch, 1\ 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 1^ lbs. oxalic acid previously dissolved in 4 pints hot water. No. 126. Pale Blues are made from the dark blue No. 125, by reducing with gum-sub- stitute water, say 1 of dark blue and 7 of gum water for pale blue, for two blues, and 1 of dark blue and 14 of gum water for blotch or ground blue. No. 127. Green. — 4 gallons berry or bark liquor at 12° T., 3 lbs. alum, 6 lbs. starch ; 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., IJ lbs. yellow prussiate of potash, 0| oz. alum, f pint acetic acid, 16 quarts 4-lb. gum-Senegal water, 8 oz. weight muriate of tin liquor at 12° T., f pint extract of indigo. No. 129. Dark Broivn. — 21 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 arc 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 in 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 water, 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. binoxaUuc 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., 4| lbs. starcli ; boil, and add 8 oz. binoxalate of potash, 8 oz. oxalic acid, li lbs. pink salts, ^ pint oxymuriatc of tin at 120° T. No. 134. Standard. — 2 lbs. fine ground cochineal, 6 quarts water, 1 quart red liquor at 20f 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 2^ quarts extract of indigo. No 136. Standard Blue. — 10 l))s. yellow prussiate of potash, 3 lbs. alum, 2 lbs. oxalic acid, 4 gallons water, 4 gallons G-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 qu»ts lavender liquor No. Ill, 6 oz. oxalic acid, 2 oz. measure ex- tract of indigo. No. 130. Lavender Lujnor. — 2 gallons red liquor, 10 lbs. ground logwood ; steep 12 hours, and strain off. CALICO PRINTING. 275 No. 140. Dove. — 6 quarts blue for doves No. 141, 4 quarts lavender liquor No. Ill, 8 quarts 6-lb. gum-Senegal water. No. 141. Blue for Doves. — 5 quarts water, 2 lbs. yellow prussiate of potash, 2 lbs. alum, 5 quarts 6-lb. gum water, 1 pint extract of indigo. No. 142. Orange. — 3 gallons berry liquor at 10° T., 9 lbs. gum-Senegal, 3 pints red mordant No. 146, 12 oz. muriate-of-tin crystals; boil 15 minutes. No. 143. Drab Standard. — 6 quarts purple liquor No. 144, 1 quart bark liquor at 10° T., ^ pint red liquor at 20° T., J pint extract of indigo. Drabs are made from this by reducing with gum water about 1 to 3. No. 144. Purple Liquor. — 1 gallon lavender liquor No. Ill, 3 oz. oxalic acid. No. 145. Silver-drab Standard. — 3 quarts gall liquor at 12° T., 2 quarts standard blue No. 136, 1 quart lavender liquor No. 111. Colors reduced with gum water from this, 1 to 2 or 3. No. 146. Red Afordant. — 1 gallon water, 6 lbs. alum, 3 lbs. white acetate of lead ; stir till dissolved, let settle, and use the clear. No. 147. Buff Standard. — 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. Olive. — 1 quart lavender liquor No. Ill, 2 quarts berry liquor at 10° T., 2 quarts 8-lb. gum-Senegal water. In mousseline-de-laine printing success depends more on the bleaching and preparing of the cloth than in any other style. To Mr. John Mercer is due the merit of having effected an improvement in the preparation of woollen fabrics, the importance of which can hardly be overrated. 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 whole 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. Pink. — 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. — l^gallon water, 1 lb. yellow prussiate of potash, 6 oz. alum, 1| lbs. starch; boil, and add | pint nitrate of iron at 80° T., H gills oxymuriate of tin at 120° T. No. 152. Brown. — 1 gallon berry liquor at 8° T., 2 lbs. ligiit British gum ; boil, and add 1 lb. muriate-of-tin crystals, 2 quarts spirili 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 protoniuriate of iron at 80° T., 1 pint oxymuriate of tin at 120° T. No. 154. Orange. — li 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. 15(\ 1 gallon spirit blue No. 151. No. 156. Red. — 3 gallons Sapan liquor at 4° T., 1 lb. sal ammoniac, 1 lb. verdigris, 4i lbs. starch; boil, cool, and add 5 lbs. pink salts, 1 lb. o.valic acid. 276 CiU^ICO PRINTING. No. 157. YellouK — 1 gallon berry liquor at 10° T., -i lb. alum, 1 lb. starch; boil, and add 1 pint muriate-of-tiu liquor at 120" T. Xo. 158. Green. — 1 gallon spirit blue No. 151, 1 gallon spirit yellow No. 157. Xo. 159. Spirit Pink for Blocking 3Iadder Work. — 4^ gallons Brazil wood liquor at lu~ T., 9 lbs. pink salts, 3 lbs. sal ammoniac, 2 lbs. sulphate of copper, 5 J oz. oxalic acid, dissolved in 1 pint water, 4^ gallons of 6-lb. gum-Senegal water, 1^ quarts oxymuriate of tin at 120° T. Tenth Style : Bronzes. The cloth is padded in solution of sulphate of manganese, the strength of which deter- mines the sliade of brown produced ; for a medium shade of brown, suitable for discharge colors, the liquor may be 80° T. After padding and drying, pad the pieces through caustic 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. 11)0. Blue Discharge . — («) 6 gallons water, Sf lbs. yellow prussiate of potash, 10 lbs. starch, 6 lbs. light British gum ; boil, and add 12 lbs. tartaric acid, C lbs. oxalic acid, 1-J quarts pemitrate of iron ; then take (6) 5 quarts of this standard, '6 c^uarts muriate of tin at.l20°T. Xo. IGl. Discharge Yellow for Chroming. — (a) 1 gallon water, 5 lbs. nitrate of lead, 4 lbs. light British gum ; boil, and add 4 lbs. tartaric acid ; then take {h) 3 quarts this stand- ard, 1 quart muriate of tin at 120° T. No. 1G2. Discharge Green. — 2 quarts yellow standard No. 161 (a), 1 quart blue stand- ard Xo. 160 (a), 1 quart muriate of tin at 120°. Xo. 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) 2quarts of this standard, 1 cjuart muriate of tin at 120°. X'o. 164. White DUcharge. — 2 gallons water, 8 lbs. light British gum; boil, and add 8 lbs. tartaric acid, and 1 gallon muriate of tin at 120° T. J?Zaeyl-.— Spirit black No. 149. After printing, hang for a few hours, and wince in a pit with water freely flowing into 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 protomuriato 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 Ijcing then soluble in the acid, and subsequently washed away, the pigment Prussian blue and chromate of lead, also the Brazil lake, beipg left fixed in the discharged place. Eleventh Style : Pigment Printing. In this style, the ordinary pigments, such as used in oil-painting, arc mechaiiically at- tached to the cloth by a species of cementing. The first fixing vehicle used was a solution of caoutchouc in naplitha, 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 thc'u 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 Aapor 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 Avhite 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 tiie 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- albmnen in their power of coagulating by heat. There are few colors of this style printed, chiefly ultramarine blue and carbon drab. Xo. 165. Ultramarine Blue, with Lactarine. — 1-^ lbs. lactarine, 3+ pints water; mix well, and add 2i oz. measure liquid ammonia, specific gravity -880, 5 oz. measure caustic soda at 32' T. ; then having beaten up 3 lbs. ultramarine with IJ pints water, mix with the lactarine solution. Xo. 166. Ultramarine Blue v;ith Alb'umen. — 4 lbs. iiltramarine, 34^ 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-tnigacanth water at 12 oz. per gallon. CALICO FEINTING. 2T7 No. 167. Ultramarine Blue with Gluten. — 6 lbs. ultramarine, 5 quarts water; mix, and add gradually 3^ 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 made by altering the quantity of ultramarine. Xo. 168. Drab. — 3 lbs. lampblack, 3 pints acetic acid at 8' T. ; mix well together, and add a solution of 3 lbs. albumen in 3 pints water ; then add 3 pints 12-oz. gum-tragacanth water. 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 of 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 plau was to attach to an or- dinary single-color machine an Indian-rubl)er 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#nable 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 tiie piece left the apparatus. The saving of in- digo was said to be considerable, but the plan was not generally adopted. Safflower Dyei.vg. — 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, aud 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 : — Safilpwer contains two distinct coloi'ing 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, tiie 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. 12 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, aud 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-ex- 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. MuREXiDE. — The purpurate of ammonia, or murexide, was discovered by Liebig and Wiihler 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 cantharides 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 sljort 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. no; 1 gallon water, 4 lbs. nitrate of lead, 1 lb. murexide, 1-| lbs. starch; boil. After printing, hang a few hours, then nm througli a cistern with rollers above and below, and provided witli a cover, through apertures in which the pieces enter and leave. This cistern is kept supplied with atnmoniaeal gas ; on leaving tliis cistern, they pass into water, and from that into a cistern charged with 2 lbs. bichloride of mercury, 4 lbs. acetate of 278 CALICO PRINTING. soda, i lb. acetic acid, 80 gallons water; run very slowly through this, wash and dry. In the first operation purpurate of lead is formed on the cloth, and in the second, or changing bath, the lead is wholly or partly removed, and oxide of mercury left in its place ; the re- sulting lake is a color of great brilliancy and purit)', so much so that few of the ordinary colors will bear to be looked at along with it. Though perfectly 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 clear. 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-dung at 160' F., second dung at 150" F., wash and dye with French or Turkey madder, bringing to boil in If hours, and boiling ^ hour; wash and soap twice at 180° F., wash; chloride of lime bath, (see No. 1 plate pur- ples,) wash and dry. 1 b. Black, red, white, and brown figures, covered in purple. Print in colors 4, 11, 34, and 18; when dry, cover with a fine pattern in 27, (12 shade;) age 3 nights; fly-dung at 170" F., second dung at IGO' 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 \)'m, which has the effect of giving a uniform shade) in 7, (10 shade;) age three nights, and treat as described under the head Sinss Pinks. 1 d. Some printers prefer to moi-dant for Swiss pinks with alkaline mordants, consider- ing the compositionjof the colors to be a guarantee against their containing iron ; 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 J cwt. cow-dung at 110° 15 miuutes; wash and dye as for 1 c. In this method of mordanting, the aluminate of soda that has escaped decomposition by the carbonic 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 garauceux, (see p. ^263.) 2 b. Black, chocolate, red, and purple. Print as 2 6, but dye with purple garancin, (see p. 263.) 3 a. For chintz work treat as 1 a, 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 described for steam colors. 3 b. Black, 2 reds, blue, green, and yellow covered in drab, or other shades. Print in 4, 6, and 7; dye, &c., as 1 «; 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 150° 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 liriuor at 5° T. when dry. After obtaining the ground shade by any of those 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-iu as groundwork, which is made and fixed as follows : — 171. Pea Green. — («)Standard : 6 lbs. siflphate of copper, 1 gallon water, 4 lbs. brown acetate of lead; di.-vsolve, let settle, and use the clear. — (6) Color: 2 measures of standard, 1 raea-sure of 7 lb. gum-Senegal solution. After i)rinting, 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 lifjuor should be heated to 1 10" 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 cistern.s, each mounted with a hand reel, and containing aliout 200 gallons each, are st>t with carbonate-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 l)lues. 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. Where fast green has been printed, the pieces are winced in bichroiiiate-Oi'-pota.-h 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 CALICO PRINTING. 279 and raise as follows: — Wince 14 minutes in caustic soda at 2° T. at 110° F., then wince in water till quite bufi" then wince in 4U0 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 produced 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 170' 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 hquor 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 bark liquor at 16° T., 2 lbs. alum, \h lbs. sal ammoniac, 14 lbs. gum-Senegal. Red. — 3 gallons of cochineal liquor at 4° T., li pints bark liquor at 12° T., 3 lbs. starch ; boil, then cool, and add I lb. oxalic acid, 1 lb. muriate-of-tin crystals. Yellow. — 3 gallons of bark liquor at 16° T., 8 oz. aliun, 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. gum-Senegal water. Calico, &c., printing has, since the repeal of the duty, risen steadily in importance, till 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, (be, employed by the trade in England aiid America in 1840. Cylinder and Surface Machines. Flat Presses. Discharging Presses. Tables. Lancashire .... Scotland .... Ireland America 435 75 18 109 2 82 1 124 8,275 4,997 '■ 300 884 Since that period there are no data as to the number of printers in Great Britain ; but Mr. John Graham, in an unpublished " History of the Lancashire Printers," gives a table, which he was at considerable care to compile from perfectly trustworthy sources, showing that in the Lancashire district, which includes also the contiguous counties, there were, in 1846, 128 firms, employing— 549 cylinder machines. 33 perrotines. 7,187 block tables. The producing power of the Lancashire district having thus been doubled in 6 year.'. Several printing firms, both in England and Scotland, have since that period much enlarged their powers of production. There are many who manufacture liV'OO pieces of printed cloth per week ; and there are four concerns, of great magnitude, who.-e united production at the present time probably does not fall short of four millions of pieces per annum, or nearly '/^ of the total quantity printed. The following estimate of the exports of printed goods is from Mr. Potter's Lecture before the Society of Arts, as reporter for printed fabrics exhibited in the Exhibition of 1851:— "In reference to the exports of printed goods, our information is rather obscure, owing to their being classed with dyed goods of all kinds." " After considerable thouglit and calculation, I have ventured to estimate them for 1851 at 15,544,000 pieces, or rather 280 OATJCO PRINTING. more than thrce-fourthg of our entire production. These goods are, however, many of them of the cheap and more staple class of prints, or slight goods suited to warm climates, and for markets where cheapness is the great recommendation. 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 goods, (exclusive of yarns,) it maybe assumed that out of £23,447,103, given as the export of 1851, about one- fourth may be placed to the account of the print trade. I have endeavored to estimate, from the Table of Exports for 1851, the probable quantity of loiopriced prints we export, and should be disposed to class them as follows : — Pieces. " Coast of Africa and the Cape 300,000 New Zealand and South Sea Islands - - - - 36,000 China, Manilla, and Singapore 550,000 British West Indies, 300,000 Foreign West Indies 300,000 St. Thomas 200,000 India 1,570,000 Mauritius and Batavia 325,000 Chili and Peru 800,000 Brazil and East Coast of South America - - - 1,000,000 Egypt 84,000 Turkey, Ionian Isles, Greece, and Malta - - - 1,000,000 Total 6,465,000 " I find those countries which take our lowest description of goods, and where the duties are chiefly very light — our colonies, India, and China, receive from us about 6i 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 Zollvcrein, 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 j)rinted and dyed in 1857. Declared real value. Yards. £ Russia 1,513,080 42,913 Sweden, 624,418 11,835 Norway 787,269 15,235 Hanover 1,954,664 49,814 Ilanse Towns 25,208,601 516,004 Holland 12,899,706 254,199 Belgium 903,764 22,600 France 5,130,677 93,366 Portugal, Azores, and Madeira - - 18,956,056 297,178 Spain and Canaries .... 3,767,747 93,084 Sardinia 11,003,456 167,807 Tuscany 6,602,902 106,110 Two Sicilies 7,438,118 123,625 Austrian Territories .... 7,191, '^73 101,663 Greece 3,379,548 60,594 Wallachia and Moldavia - - - 1,180,001 19,779 Syria and Palestine .... 16,061,817 208,140 Egypt 11,54.3,985 173,122 West Coast of Africa (Foreign) - . 18,817,282 318,982 Java 16,911,802 286,274 Philippine Isles 9,548,904 213,757 China 12,030,344 203,443 South Sea Islands .... 1,552,337 29,995 Cuba 14.144,771 249,760 Porto Rico 3,109,890 43,518 Cura^oa 783,478 13,356 St. Thomas 20,529,211 290,956 Haiti 5,191,059 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.) Declared real value. Yards. Q Central America . 5,721,458 86,007 New Granada . - 14,618,606 229,310 Venezuela . 6,564,167 107,417 Brazil . - 84,304,760 1,543,479 Uraguay - . 8,749,894 149,294 Buenos Ayres - . - 17,870,263 319,670 Chili J - 21,536,565 365,982 Peru . - 23,426,258 396,362 Gibraltar - . 7,860,972 125,567 Malta . 3,203,445 46,912 Ionian Islands - . 3,790,985 55,868 West Coast of Africa (Britisb) - 7,286,177 137,879 South AiVica (Britis h) - - 9,875,247 196,859 Mauritius - 7,556,558 111,725 British East Indies . - 89,717,000 1,515,807 Hong Kong . 2,621,464 41,201 Australia - . - 15,769,817 310,660 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 " Tlie 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, tliough 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. Tlie 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 tlie 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 inoftensive taste, whicli 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 1701, (at this period cloth of all cotton was prohibited,) and which nuist 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 285 CALOMEL. 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, bv 3 feet 2 inches in breadth. The composition in the design is very bold and free — in my opinion indicating very strongly the feehngs 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 waif 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 WiJhler 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 healing coarse charcoal powder with concentrated sulphuric acid, is passed into the hot solution : the separation of the calomel commences immediately. When tlie 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. {Cajnec, Fr. ; Cammeo, It.) Correctly a precious stone engraved in relief, as opposed to an intaglio, which is cut into Ihe 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 ii^ 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 tlie 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 faciUty, yet hard Dnough to wear for a considerable time without injury. CAMPHENE. 2S3 The natural history of the mollusca producing the shells, and the best account of the manufacture of cameos, was given by /. E. Gnnj, of the British Museum, in a paper read before the Society of Arts in 18-17, 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, {Ga>iteropoda ptenobranchiata zoophar/a,) which are peculiar for being all formed of three layers of calcareous matter, each layer being composed of three perpen- dicular laminoe 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 laminas 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 his work on the shell in such a manner, that the direction of the laminas 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 riifum,) which has a red inner coat, or what is called a sardonyx ground. 2. The black helmet, [Cassis Madagascariensis,) which has a blackish inner coat, or what is called an onyx ground. 3. The horned helmet, [Cassis cormitum,) wuth a yellow ground. 4. The queen's conch, [Strombus gigas,) with a pink ground. The bull's mouth and the black helmet are the best shells. The horned helmet is apt to eeparate from the ground, or double, and the last, the queen's conch, has but seldom the two colors marked with sulHcieut 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 il/ac^ai^asear 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: Price. Value. Bull's mouth - - - 80,000 - - Is. 8c/. - - £6,400 Black helmet - 8,000 - - 5 - - 1,920 Horned helmet - - 500 - - 2 6 - - 60 Queen's conch - - 12,000 - - 1 2^ - - 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 l^-ench capital, where not less than 300 persons are engaged in the manu- facture. Nearly all the cameos made in France arc 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 284 CAMPHOLE. forms a limpid, colorless liquid; its specific gravity is about O-STO, but it is subject to some sliuht variations; C^H* appears foiily to represent this and several other similar oils. It is very intiammable, 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 reainijied, 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 iu the camphene lamps if tliey are not properly attended to. To purify old camphene, it must be redistilled from caibonate of potash, or some simi- laily 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 cinnole and c>pno!e, which boil at 284° and 338° Fahrenheit, when collected to- gether. The specific gravity of crude camphole ranges from '88 to "OS, and the less vola- tile portions frequently contain naphthaline, which raises their specific gravity. This sub- stance, either alone or mixed with pyroxylic spirit, is applicable for burning in lamps or for dissolving rosins, as a substitute for oil of turpentine. CAMPHOR. There are two kinds of camphor imported : — .I.M'AN Camphor, called Dutch Camphor, because it is always brought by the Dutch to England. It comes by the way of Batavia, and is impoi-ted 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 iu chests lined with lead-foil containing about li cwts. It has been suggested to introduce the camphor trees into other countries. South Georgia and Florida are named as suitable localities. The Laura campjhora is 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 oO feet. The wood of the camphor tree is in favor for carpenter's work ; it is light, easily worked, duraljle, and not lial)le 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 cachcll, or small head - - - - = 3'o 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 phiced ujjon 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 gold by the Chinese ; or it may bo 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 18uG were: — Camphor, unrefined 4,505 cwts. " refined G26 " 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^^IP^HCl, is white, transparent, lighter than water, and has a camphoraceous taste. The fluid is termed liquid artificial camphor, or terelnne. CAilPHOR, OIL OF LAUREL. When the branches of Camphora ojficinarum are distilled with water, a mixture of camphor and a liiiuid essential oil is obtained. This is the oil of camphor; it has a density of O'.UO, and its composition is C'lI'^O. By ex- posure to oxvgon gas, or to the action of nitric acid, it absorbs oxygen, and becomes solid camphor, C^IP^O^ This is an esteemed article in the eastera 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 Hghted reed is placed in it for about 10 minutes, and iu the space of a night the cavity is tilled 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 largo dimensions, from 2i to 7 feet in diameter. The same tree that produces the oil, would have produced the camphor if unmolested, the oil being supposed to be the Urst stage of the camphor's forming, and is consequently found iu 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 ..--.-..2i 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, aad to rise up and diti'use 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, iuflu- encl&s 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, and has been introduced into, and has flowered in, this country. CANADIAN BALSAM. A product of the Abies balsamea, 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 earned 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 do Chimie," describes treating oils with half their weight of concentrated sulphuric acid, by which their melting point was greatly raised. Ho gave, however, particular directions that tlie matter under process siiould be "kept cool. Instcail 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.f cwts. of concen- trated sulphuric acid, at a temperature of .350 ' F. In this process tlie glycerine is decom- posed, large volumes of suli)hurous acid are given off, and the fat is changed into a mixture of fat acids, with a very high melting jioint. This is Wiishcd, 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 Ciises reduce the quantity of acid employed to 4 lbs. and even 3 lbs. to a cwt. of the fat." In 185-1:, Mr. Tighlman obtained a patent for the exposure of fats and oils to the action 286 CANDLES. 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- punip, 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 6U0° or '/OO" F., heated by passing 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 biiek 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 mi.xture 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 caia-ied 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, lo 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 wa.shed, by being boiled up (by means of free st«am) 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. Best 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 fit, 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 luis 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 2<)0 frames of moulds, and each contains 18 bobbins, starting each with 60 yards of cotton wick. K/i//it-Lig/ifs. — 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 arc 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 iu 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 Ea.st 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 sujiport palanquins. The smaller kinds are used for walking-sticlcs, 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 hundred 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 Aiigiga. 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. CAXXABIC 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. CANNEL 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 Jkt,) 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, screwed, or eccentric turned, the plank way, 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 tlie shafts of columns, should be cut from either edge of the slab, as the laminae 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 ^luseum m;iy be seen a snuff-box of cannel coal, said to have been turned in the reign of Charles I., antl 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 workccl with tiie 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. CANNON. See Artillery. CAOUTCHOUC, GUM-ELASTIC, or INDIAN-RUBBER {Caoutchouc, Fr., Kautschuk Federharz, Germ.) occurs as a milky juice in several plants, such as the xiphonia, cahuca, called also hcvca guiancnsi.i, cauischur, Jalropha clastica, castillcja elastica, cecropia pel- leta, fieus rcligiosa 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 ia dried it loses 55 per.cent. "1 288 CAOUTCHOUC. 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 surfoce. It mixes with water iu 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 I'ur 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 en)plo.yed 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 painters slab and muller, and other simple means were resorted to. Macintosh, Ilancock, 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 eftect 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 lilocks 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 v.-cre the purest form, but larger quantities of rub- ber could lie 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 macliine for the purpose. (See Jiff. 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- jetted 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, lumjis, shoes, &c. ; a charge of one pound pave 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 tlie 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 lemarks 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 the 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) arc sifted on and incorporated with it, by means of the usual kneading apparatus. When very thin films are reciuircd, (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. Vol. III.— 19 290 CAOUTOHOUO. 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 7 tons before it burst. To remedy the evils of this form 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 Oct. 21st 1826 weight Oct. 25th 1827 K Oct. 2d 1885 11 Nov. 1844 " Oct. 1849 1( Feb. 1851 (1 May 1854 (( b. oz. drcb 1 1 4 1 1 2 1 14 12 13 4 7 8 3 14 3 12 In 1856 it was cut open and weighed 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 flie sun and from close packing, has been obviated by a discovery adopted by Messrs. Warne and Co., termed by them the Sincalor process, ( si7ie ca/ore, 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 iisual 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 i)ow 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 harsh 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- CAOUTCnOUO. 291 als are employed, "metallized" and "mineralized," " thiouized," 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 cliaracters, its elasticity is greatly increased, and is more equable ; it is not affected, nor is tlie 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. Furtlier, 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 leatlicr. He called the attention of his brother, as well as other individuals who w^cre 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 siuiple 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 caoutciiouc, 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 term 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 got 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 clastic, 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 protocliloride of sulphur, for a minute or two, and then immersing them in 292 CAOUTCHOUC. 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 26" Beaumo at the temperature of 248° Fahr., then washing in au 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. Vulcanized 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. 'NVhite lead, sulpliuret of antimony, black lead, and other substances enter into these combinations. Alter 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 difBculties 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 jiure 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 was not a matter of indifference ; if of tin, the article was usually delivered perfectly clean, but if of brass or copper, then the material adhercjd 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 Mi-. 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 wide, 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 vidcanized Indian-rubber, 1 h 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 tlie 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 50 yards long, and 56 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 sheatliing 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 firm 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. 3. Durability. 4. Insolubility. 10 6. [Inalterability by climate, or artificial heat, or cold. 6. Inadhesiveness. 11 7. Impermeability to air, gases, and 12 liquids. 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 manuf\ictiired 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 comieetion 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 jtressure has ceased, in one word, the elasticity of the Indian-rubber, is increa.sed to such a degree by vulcanization, that comparing the improved with the original article, it maybe 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- 8. Plasticity. 9. Facility of receiving every style of printing. Facility of being ornamented by painting, bronzing, gilding, japan- ning, and mixing with colors. Non-electric quality. Odor. 294 CAOUTCHOUC. riage springs, measuring -6 inches outside disk, 1 incli inside disli, and 6 inches deep, was taken and exposed to pressure : — A pressure of ^ ton reduced it to - ditto 1 ditto ditto U ditto ditto 2 ditto ditto 2i ditto ditto 3 ditto ditto H ditto 57, a deep 5'/. 6 do. 47>B do. 47.6 do. 3'7,6 do. 3"ia do. H do. 3 do. ditto 4 ditto ... 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 - - 20 lbs. to square inch. 2 Ply for conducting water " - SO to 40 " 2 Ply stout " - - 75 " 3 Ply for brewers, &c. " - - 75 " 4 Ply for steam and fire-engines " - - 175 " 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 case 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 water, 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 l)earings, 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. Viands 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. Lacey Melville - 3 Walker and Mills 4 W. C. Fuller - 29th Mar., 1825 13th April, 1844 3d July, 1845 23d Oct., 1845 5 Adams and Richardson 24th Mav 184'7 C. De Bergue Y I Wrighton 8 C. De Bergue 9 Normanville 10 C. De Bergue 11 P. R. Hodge 12 G. Spencer 13 P. R. Hodge W. Scott J. E. Coleman 16 I Fuller and Knivett C. De Bergue - G. Spencer R. E. Hodges - G. De Bergue W. C. Fuller E. Lund - W. C. Fuller E. Miles - G. Richardson W. Scott - G. Spencer R. Eatou . R. Eaton - 26th July, 1847 22d Dec, 1847 5th Jan., 1848 2d May, 1848 1 5th April, 1850 8th Mar., 1852 2d Feb., 1852 8th Mar., 1852 8th Mar., 1852 2d June, 1852 6th Oct., 1852 26th Mar., 1853 ! 2d July, 1853 2d Nov., 1854 4th Mar., 1854 10th May, 1854 i 18th Aug., 1854 10th Jan., 1855 12th Jan., 1855 28th Nov., 1855 14th May, 1856 25th July, 1856 20th Nov., 1856 8th Dec, 1856 H. Bridges - . 14th Mar., 1857 J. Williams - - 11th Nov., 1857 W. E. Nethersole - Indian-rubber springs for carriages en closed in cases with dividing plates Springs for buffers and bearing, sphere" of Indian-rubber and air, withdivid- ing plates, and enclosed in iron cases Buffers, Indian-rubber bags, enclosing air, in iron cases. ° Buffer and bearing springs of Indian- rubber, cylindrical rings with divid- ing plates of iron. Elastic packing for axles. Indian-rubber buffer, bearing and draw springs. Indian-rubber shield for axle box Anti-recoil buffers of Indian-rubber and improvements in dividino- plate^' Indian-rubber shield for axle box. Station buffers of Indian-rubber and carriage buffers. ' Packing for steam joints. Indian-rubber cones as buffer, bearing and draw springs. *' Indian-rubber compound springs, In- dian-rubber to wheel naves, and to axle box shields. Indian-rubber as check springs, wheel nave, suspensor springs. Indian-rubber applied to buffer, bear- ing, ^nd draw springs, rails, chairs and sleepers, wheel tires, windows axlebearings, plummer blocks, con- necting rods, steam hammer beds Common road springs of Indian-rub- ber. Indian-rubber bearing sprin"-s (Pat- ent refused.) ° " Improved cones for buffer, bearing. I and draw sprint^s. Improvements in fastening Indian-rub- ber springs. Buffers for railways. Indian-rubber springs applied to an- chors, cables, towing ropes, deck ropes, Indian rubber to feed-pipe, coupling and water joints. Indian-rubber springs to common roads. Indian-rubber to water-pipe couplings. Indian-rubber -buffers with Spencer's cones. Indian-rubber to axles and tires of wheels. Indian-rubber to feed-pipe, couplings for locomotives and tenders. Indian-rubber springs for railways. Indian-rubber springs in thin lam'ina; for buffer, bearing, and draw springs and lifting-purposes. ' Spencer's cones applied to wood blocks m buffers, bearing springs, &c. Indian-rubber springs applied to the side or safety chains of trucks, &c 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 ia Laceyh 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 hst,) 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 Hills 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, ia thicknesses varying from -J to 3 inches, and with diameter of ring suitable to the power of spring required; between eacli of these cylindrical rings he places a thin iron plate, through a hole in the centre of which passes a guide rod. Mg. 141 shows Fuller's spring in section and plan. These ^^- 141 m xd 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 (see Hst, 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 a -- — ^ chouc loses its power of stretching laterally, being held by the ring b, 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, Vale of Xeath, Bristol and Exeter, Taff Yale, Lancashire and Yorkshire, St. Helen's, Bombay and Baroda, Thciss 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 tlie result of an experiment on a No. 1 cone, (for inside buffers,) 3 inches iu length, 3J inches diameter at ring, 5 inches diameter of ring. 1st Experhnoit, without the confining ring, weight of cone 1:|- lbs. Inches. Giving a stroke of Without any pressure the cone measured - - 3 - - With pressure — 280 lbs. " - - 24- - - -| inch. '« — 148 lbs. " . . 2 - - 1 " " —672 lbs. " . . u . . u " 2c? 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. " " ... 9i u 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^s improvement (see list. No. 15) consists in the use of iron rings to confine the lateral swelHng of Indian-rubber cylinders. (See Jig. 143.) They are used as bearing 143 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 with one of Coleman's cylinders with and without the rings. Cylinder 6 inches long, 6 inches diameter, 1 inch hole, weight 9 lbs. ■Without the confining rings. With the 2 confining rings. Tons pressure. Inches Length. Inches Length. .... 6 - - - . 6 i - - • - 5Vi8 - - - . 5'Vio 1 .... 5 . . . . 5| H - - - ■ - 41 - - - - 5i 2 .... 4i - - - . 5A 2i - - - - 3f - - - - 5i The ne.xt form of these springs is R. Eaton's, (sce/y. 144 ; and list, Nos. 28, 29.) This 144 298 CAOUTCHOUO. spring seems to be peculiarly adapted to use where a powerful spring, acting through a small space, and taking little roon;, is required, as for use in mining ropes and chains, (sec Safety Cage ;) iron ropes, for siiip-rigging, for engine-springs, station buffers, and pow- erful draw-springs. Eaton's main idea is the use of lamina? of Indian-rubber, of a maxi- mum thickness of i 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 httle 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 : tlie spring was built up of 2i laminae, -^ 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 ofiBce, in Cannon Street West, London, (see Proving Machines.) Experiment. Length including plates. Tons. Area of spring, 19 square inches. 87.6 10 . - - 75 2-0 -TVis 3-0 VU, 4-0 6i 5-0 6f 6-0 6f "^-O 6i 8-0 6| 90 6| 10-0 6| Hodge's compound spring (Xo. 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 Jig. 146 ; and list, Xo. 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. Brulffes' Patent. — (See list. No. 30,^1^. 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. 146 299 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. 14Y 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'^ Patent. — The applications for common road carriages, patented by Mr. Fuller of Buckjersbury in 1852 and 1855, have been extensively used, both in the form of cylindrical rings acting by compression and also of suspension springs for lighter kinds of vehicles. Respecting these springs, /^s. 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 t!)e 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. Tlicy arc 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, and 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, accordin"- to the strength required. 148 149 Another important adaptation of Indian-rubber by Mr. Fidlcr, is tliat of anchor springs, towing ropes, and spiings for the recoil of guns and mortars. During the Russian war, about TJO 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 powerfid spring adapted to the chain cables of vessels when 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 railicny chairs. — Several proposals have been devised to this end, and a number of plans are given in Coleman s 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 iires. — 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 wear of the tires. For wi7idou'S. — 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 |- 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. Lund, Spencer, and Fenton have also 151 150 CAOUTCHOUC. 501 introduced the use of rings of this material to form a joint between the locomotive and tender, {fi(i. 151.) They are extensively used, and entirely prevent the leakage common to the old ball and socket joints, and are much cheaper in first co.st. Rings of Indian- rubber were proposed by Mr. Wicksteud, for closing the socket joint of water pipes, and they are used in a variety of forms for that purpose. Messrs. W. B. Adams, NormanvUle, Wrighton, and Hodge have also introdvjced the use of shields and rings of Indian-rubber for keeping tlie 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 niade 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 CaOUTCIIOUC. 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 aflected. 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 sun'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 cstal)lished tliat 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 tlie sun, either in hot weather or cold, it becomes solarized, or divested of its adiicsivc qual- ity ; whereas, no other kind of light or heat has any similar effect, until the high de.;ree 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 Ixdian-Rcbbkr. Macintosh and Hancock give the following descriptions of their trade qualit}', to guide practical men ; other manufacturers may also have similar scales of rubber. A quality is the most clastic, it weighs about 00 lbs. per cubic foot, or Vae of a lb. per 302 CAPILLAIEE. culjic inch, (this is understood to mean pure sulphur and caoutchouc, all other qualities are mixtures.) D quality weighs 82 lbs. per cubic foot, or '/ji of a lb. to 1 cubic inch. E quality, more elastic than D, weighs about 92 lbs, to the cubic foot, or '/le of a lb. to 1 cubic inch. F. c. Fibrou? compound, used for flange washers, valves, and pump-buckets, weight Vas 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 Vse 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, arc 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 off, varying in thickness from '/ic of an inch to Vto 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 diifered 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 loonx. 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 Macintosli 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 probal)le 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 aileriuate 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 manuf\icture and vulcaniza- tion of rubber, as is contained in this specification. If any of my readers," he goes on to sav, " can point out such a document, I shall feel obliged if they will inform me of it." This is the patent of 1843. CAPILLAIRE. 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 Keichcnbach in * Porson.il Narrative of tlio Origin jind Prnjrrpss of Caoutchouc or Indian-Eubber manufactured in England, by Thomas Il.ancook. London, IsriT: Lonsn^an and Co., 8vo. pp. 2S3, (plates.) Gum Einstic and its Varieties, with a detailed Account of its Applications and Uses, and of the Pis- coverv of Vnleanization; by Charles Goodyear. New Haven, U. S. Published for the Author, 185.3, 2 vols. Svo. pp. 246, 379, (plates.) CARBOLIO 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 allovr 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. CAPRYLAMINE. (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 oi eri/thlna, 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 ds marc.) It requires 74 carat grains and '/le 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 cai'at is becoming common. CARBOLIC ACID. (C'^H^'O^ Syn. Phenic Acid, Phenole, Fhcnylic Alcohol, Ify- drate of Plicnyle.) 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 bo 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 319' will consist, not of carbolic acid, but of its homologue, cresylic acid, C"II''0-. Commercial carbolic acid is generally very impure. Some specimens do not contain more than 50 per cent, of acids soluble in strong solution of potasli. The insoluble portion contains naph- thaline, fluid hydrocarbons, and small portions of chinolhie and lepidine. Car))olic 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 TOOS. Carl)()lic acid, when mixed with lime and exposed to the air, yields rosolie acid. Tlie 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 l)asc to enable it to exist, consequently the carbolic acid of the air destroys tlie color. {Dr. Avr/us Smith.) I find tliat homologues of carbolic acire found in peculiar strata, thirty feet under the surface of the earth, in a small tract 310 CARRAGEEN". among the Rajepiplee hills ou 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 Cainbay. 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 Neemoudrn, a village of the Rajepiplee district, and three miles cast, 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 arc 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 nmst 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 they have undergone the process of burn- ing. From Xeenioudra they are carried by the merchants to Cambay, where they are cut, polished, and formed into beautiful orniimcnts, for which that city is so justly celebrated. — Cojwland, Boinbni/ Researches ; Hamilton's Description of Ilindostan, 4to. 1820. Tlie 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 fle?h-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 Carnklians 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, 1857 :— African Coast 20,583 Ar.abian Gulf 26,157 Cevlon 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. CARR.\.GEEN. {Chondrns crispus.) Irish Moss. See Alg.«. CARRAGEENIN. The mucilaginous constituent of carrageen moss. It is called by some writers rer/etable jellj/ or rer/i'tabfe 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 Ls 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, Crom starch by its not assuming a blue color with tinc- ture of iodine; from animal jelly, l)y 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." Tlie composition of carragcenin dried at 212" F., according to Schmidt, is represented by the formula C^II'^O'", so that it appears to be iden- tical with starch and sugar. Mulder, however, represents it by the formula C-'H"'0'°. CARTHAMUS, or SAFFLOWER. The coloring matter of safflower has been exam- ined by Salvetat; who has found nnich difference in carthamus of reputed good quality ; a few of his results will suffice : — CAKVING BY MACHINERY. 311 1. 2. 3. 4. Water G-0 11-5 4-5 4-8 Albumen ------- 3-8 4-0 8-0 1-7 ' Yellow colorinff matter a - 27-0 30-0 30-0 26-1 i " " " 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--1: 41-77 38-4 56-0 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 Sulvetat 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 tlie 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 oVjject 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 scries 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 hy 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 ; it, 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 b is the axis of a revolving tool, which is driven by the belts <•, J, «, and the compound pulleys/, g, h, which increase the speed at each step ; f, g, h, is the table on wliieh the work is fixed ; i, k, the work ; and ^•, I, 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 sliown 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 in, ?(, 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 pan 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 tliat opening in the templet is produced ; this process is repeated for every other open- ing, and thus a series of recesses ai'c 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 arc 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- cal)le 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 arrangen.ents pre- viously described. In that of 1843 he particularly claims all combinations for accomphsh- 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 Irame 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 produced, 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 admiraWe 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 184.5, since which date it has been in constant operation in producing the carved decorations of the interior of the Houses of Parliament. Its princi])le 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 revolvinrf 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 olyect of using machinery is to lessen the cost of production, or to save time ; and in appproacliing 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 th-e 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 sliould only be roughly pointed. Fig. 154 is a plan of the machine, fg. 155 a front elevation, and fig. 150 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 tlie otlier, but each capable of acting simultaneously and in unison with the other. The first, or horizontal part, is the bed plate " fioating-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 wiiich 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, n, c, n, which is a rail- way supported on piers from the floor and fixed strictly level. The carrying frame i, J, ic, 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 tal)le 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 motion 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, 0, 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 such 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 ecjual to half that of the taljle, 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 814 OAEYIN'G BY MACHINERY. 155 Qq;:::::::::" 156 -% ^. wr^ CASE-HARDENING. 315 adjust the force with which the toola 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, (/, e, f, g, is the pattern or original carving whicli is to he copied, and /(, i,j, k, 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 commurficated by the cord z, which is fastened to each end of the bed plate, and makes one or two turns round the pulley k. Wiien 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, in, 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 fi, i, J, 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 ail 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 wo should go into the various applications of this machine, to the manufiicture of printing blocks, ship's blocks, gunstocks, letter cutting, tool handling, cabinet shaping, &c., &c., all of wliicli 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 tho 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 isi 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-HARDENIXG. 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 t!io 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. — ILdtzaplfcl. The recent application of prussiate (ferrocyanatc) of potash to this purpose is a very interesting chemical proljlem. The piece of iron, after being polished, is to be made brightly red-hot, and then rubbed or sprinkled over witli the above salt in fine powder, upon the part intended to be hardened. The prussiate l)eing decomposed, and apparently dissi- pated, the iron is to bo quenched in cold water. If the process liivs been well managed, the surface of the metal will have become so hard as to resist the file. Others propose to smear 316 CASK. over the surface of the iron with loam made into a thin paste with a strong solution of the prussiate, to dry it slowlj-, then expose the whole to a nearly white heat, and finally plunge the iron into cold water, when the heat has flillen to dull redness. See Stekl. "^ CASK. {7'o7inean, Fr. ; Fa.ss, Germ.) Much ingenuity has been displayed in cuttin"' 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 \lie circle, the true direction of the joint as shown by the dotted circle Jirj. 157, 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, fg. 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 ibund inappli- cable to large staves, and these are cut, as shown in three views, fg. 159, whilst attached 158 159 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 block run in two curved grooves g rj 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 sime 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 arc 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 l>y aroniatics. It is used to flavor soups, and other dishes, and is the basis of the West Indian dish prpper-pot. In French Guiana, the term cabion is applied to a similar condiment. — Percira. CASSITERITE. Oxide of Tin ; Stream Tin. Stream Tin is the alluvial dlbris of tin veins. (See Tin Ore.) This is one of the very olyectionablc 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 the following account of the purple of cassius, and of its preparation : " AVhcn protochloridc of tin is added to a dilute solution of gold, a purple powder falls. It is obtained of a finer tint when protochloridc of tin is added to a solution of the sesqnichlo- 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 rubbed to powder, it is of a dull bhie color. Heated to redness it loses a little water but no oxygen, and retains its former appearance. If washed with anmioiiia, on the filter, while still moist, it dissolves, and a purple liquid passes, which rivals the hypermanganate of potash in beauty It may al.so be formed by fusing together 2 parts of gold, 3i parts of tin, and 15 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." CEDAR. 317 " Berzelius proposed the theory that the powder of Cassius may contain the true prot- oxide of gold combined with sesquioxide of tin, AuOSu^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, AuOSn'0^=Au-|-2SnOo." — Grahaui and Walts. 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 fiitty 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. — 0. G. W. CASTOR OIL. The expressed oil of the seeds of the Palma C/irlsii 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 reu)i of the oil has undergono 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 malt, — 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 Acid. When Gambir catechu is treated with water, an insoluble residue is left, which has been termed by Nees resinous tannin. Its composition is C'^H"Ol CAT'S EYE. A translucent quartz, presenting peculiar internal reflections. This effect is said to be owing to filaments of asbestos. When cut en cabochon, it is esteemed as an ornamental stone. CEDAR. {Cklre, Fr. ; Ceder, Germ.) The cedar of Lebanon, or great cedar, {Pimis cednis,) 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 tiio whole group of mountains which is situate Ijctween Damascus and Tripoli in Syria, and which includes tlie Libanus and Mounts Araa- 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 tlie Lcl):iiion species, wo must l)elicve that its distribution at one period extended over countries where no trace of its having existed now remains. Egypt, Crete and Cyprus are mentioned l)y I'hny and Tlieophrastus as native habitats of the cedrus ; we may thus fiiirly infer that the ccdrus of the ancients as fre- quently had reference to the other coniferye as to the Lebanon species. The pencil cedar is the Junipcrus Virrfijiiana. It is imported from America in pieces from 6 to 10 inches square. Tiie grain of the wood is remarkably regular and soft, on which account principally it is used for tlie manufacture of pencils, and from its agreeable scent for the inside of small cal)inets ; it is also made into matches for the drawing room. 318 CEDEIKET. 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, wlien 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 Cup7-essus or Jimijjerzcs, which also afford odoriferous resins, it is now impossible to ascertain. 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. 51r. Vulliaray 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 goin^. 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. Farcy's obser- vations, also communicated to the Institution of Civil Engineers, still more show the extraordinary atmosphere produced in close caliinets 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 strong odor of cedar, and troublesome to rcm.ove ; the bright surface of the crystals appeared as if varnished in an unskilful manner. The cedar 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 tlie 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 inflammal)]e, burning with a great flame. This case was laid before the officers of the So- ciety of Arts, who are desirous of extendir;g 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 oVttained at a certain epoch of the distillation, which, when dropped into persulphate of iron, forms a network of crj-stals. This is cedriret. It has not yet been observed in coal naphtha. CELESTIXE. (S/rontiane sulfatlc, Fr. ; Co'exfris, Germ.) Celestine is usually asso- ciated with secondary or Silurian limestone or sandstone, also with trap-rocks ; and it is fdund in the red marl formations associated with gypsum. In Sicily it is commonly asso- ciiited with sulphur. The celestine of Girgenti was found by Stromeyer to be composed as follows : — Sulphuric acid 48-08 Strontian --....... 56'y5 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-rooks 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. (^Gimentx, Fr. ; Cdmcntc, 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 ie 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 ashes to 14 lbs. of pitch are employed, and the cement, if too bard 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. — Jaines'.i 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, onvx, cat's eye, sardonyx, carnelian, and sard. CHAMOMILE FLOWERS. The Atit/iemi.'s nobilh of Linnaus. 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 hojjs in bitter beer. It would be well if no more objectionable bitter were employed. In 185G 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 vroon, the follo«'ing list has been compiled for this work by the kindness of a friend engaged in tliose manufactures. For more specific information, see Dkstrdctive 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 cxaniinod chemicidly, found to be very complex in character and constitution, many of them being very little understood. They are gaseous, liquid, and solid. Tlic gaseous products are those not condcnsible by ordinary means, viz. : — Carbonic oxide. Carbonic acid. Light carburcttcd hydrogen, or marsh gas. defiant gas. 320 C)SE£SC Ordinary naphtha, ov \ /^,^^^^^ ^j. ^^^^^y , ^^ ,,^^.^, .j pjrohgaeous spirit. | ^,,^o,,,/syn. with pyroacetic These are usually employed (such as are combustible) for heating purposes iu the manufactories where found. llic liquid products are water, containing from C7o 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 hst will comprehend the greater number of these bodies : — Water. Acetic acid in its crude state, called pyroligneous acid. Ammonia. ( Hydrate of mcthjile, syn. with spirit of wood and methylic alcohol. ' rie acetic aether, lacetic spirit. r Benzole, ■^ '. "j J y .1 1 '^' (According to the researches of Cahours these are all hydro- ■ 1 tl i r l' r carbons, and separated by him from crude spirit of wood. \. Cymole. J From the distillation of tar are obtained, besides many of the foregoing, which would come under the name of " lif/ht ollx" from their low specific gravity : Oils heavier than icaler, besides residuary resin or pitch — Xylite. Picamar. Paraffine. Mesite. Cedriretc. Resiu or pitch. Capnomore. Pittacal. Solid Products : Pyrosanthinc, Charcoal. — C. EI. B. H. CHEESE [composition of) : — Ash of the substance. Nitrogen. Fat. TVater. Free Normal. Dry. Normal. Dry. from ash. Normal Dry. Per Ct. Per Ct. Per Ct. Per Ct. Per Ct. Per Ct. Per Ct. Per Ct. Cheese from Chester 3ir39 4-78 6-88 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 " Neufchatel 61-87 4-25 11-17 2-28 5-99 6-07 18-74 49-15 " Brie 53-99 5-63 12-08 2-39 5-14 5-85 24-83 53-29 " Holland 41-41 6-21 10-61 4-10 7-01 7-84 2506 42-78 " Gruyere 3-2 -05 4-79 i 7-05 6-40 7-96 8-56 28-40 41-Sl Pat/en Journal Pharma. CHEMICAL FORMUL.(T}. 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 clement, 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 formuloe there are several rules to be observed, the neglect of which will lead to njisapprehension 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, diy sulphuric acid by SO^, acetic acid by C^H■'0^ But where a compound is to be expressed which is itself formed by tlie 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'^0. If it be intended to multiply a formula not containing a comma or other sign, such as SO', C^IPO'', &c., the numlier 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 2P1)0, three atoms of acetic acid, SCIPO'. But it is to be remembered that a number placed on tlic 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 f;ict 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 connevted 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. 321 of lead, we write, PbO -f- 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 -{- 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^ + 3 (NH^O,CO^) = SbO' + SXH^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 : — C^''H"NO" 4- 4H0 = C^H^O^ -f- C=NH -\- 2C"H"0" Amygdaline. Bitter al- Prussic Grape sugar, mond oil. acid. la writing the formulae ©rsubstitution 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. ( II ( CTI' ( C=H« ( C^H^ ( C'=H» ( pt ( C^n^ N-^H N-^ H N-^C'^H' N.|C-H' N -^ H N -^ pt P.^C=IP (H (II I H (cm^ ( H (11 (C=U« Ammonia. Methylamiue. Bimethy- Trimethy- Anihne. Platina- Triphosphme- lamine. lainine. mine. thylamine. In the first of the above formula? 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 t^at 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 formuke 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 cm- ployed ; for which, see some standard work on chemistry. A still more conmion 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 maybe 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.— 21 822 CHEMICAL FOEMUL^. 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 CO*, instead of. CO''. This is in consequence of their regarding it as a bibasic instead of a monolwsic iicid. 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 CH'^'O^, instead of C^H^O. 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 Hydrate of Anhydrous of water. Acetic acid. Alcohol. Ether.* _ potash. potash. O^j H '^ ^ H ^ \ CIV 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 CHW, 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, (C*H^,) and therefore write its formula C^H^O' -|- 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, C*IPO^, which Williamson calls othyle ; and another, sometimes called vinyle, C*H^, which exists in aldehyde, in olcfiant gas, and several other bodies. The radical in acetic acid is, consequently, not CIl^, 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 diflerent 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. Tjipe, two atoms of hydroc/en. — 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 Olcfiant Marsh Hydrochloric Prussic Chloride hydrogen. gas. gas. acid. Benzole. acid. of ethyle. H C'H= C-H^ CI C-H^ CN H H H H H H 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 formula? of salts are written by different authors in a somewhat different manner. Thus, sulphate of potash * For the tj-pical representation of the mised and composed ethers, see the article Ether. CHEMICAL FORMULA. 323 will, by one, be written SO^,KO, and by another SO'E. 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 formula?, founded on the theory of types ; but, nevertheless, the above illustrations will serve to explain why one person will write acetate of potash g- ' another V. ' ^ X.\iiviii C'IPO^,KO, and perhaps a fourth Cvc from Rvlplmroux 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. Tour 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. 82 'J larger quantity of test liquor, instead of 139"44, the operator may take, for example, ten times that quantity of arsenious acid, namely, 1394 41 grains, (or, more correctly, 1394-36,) and dissolve them in as much liquid as will form 10i),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 l,00i) grains- measure of the alkalimcter are divided into 100 degrees, each degree or division will therefore contain 0'5, 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 maimer : — 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 (13-9 44) 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 li(iuor 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, alwa_ys 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, protosulphatc of iron may very conveniently bo employed ; and this method, first proposed, I believe, by Runge, yields also exceedingly accurate re- sults. This method is based upon the rapid peroxidization which protosulphatc of iron under- goes when in contact with chlorine in the presence of water and of free suphuric acid, two equivalents of the protosul[)hato being thereby converted into one equivalent of persul- phate, on account of one e0 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 coui-se, the quantity per cent, of the carbonates which it contained. This being done, take a weighed quantity 332 CHLOROMETRY. 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"0^+HO,) some portion of which is always found mixed with the peroxide; every grain of water thus evaporated corresponds to 9-77 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 nianganoso-manganic oxide (Mn'O'). 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 {leroxidc. In order to eft'ect the complete conversion of the peroxide in the sample into red oxide of manganese, as above mentioned, the ignition should be continued lor a long time, and the quantity operated upon should be small ; if a larger tjuantity 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 Ijy chlorhydric acid, pro- duces only protochloride of manganese, but yields no free chlorine, as shown by the follow- ing equation : MnO + HC)=MnCl-|-HO. Kot so, however, the red oxide of manganese, or manganoso-manganic oxide (Mn^O"), 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-l-Mn''0^ or by Mn^O^, or by SMuOl^ ; therefore : l^MnO -h 1 JHC1= 1 jilO -u MnCl -1- iCl- 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'^O^, is the same as 2ilu01^ ; therefore UMnO + UHC1 = HH0 + MnCl -f -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 MnC + 2HC1= 2II0 -I- MnCl + CI. 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 IIO-l- Cl = FeW,SO'+ 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 e(iuivalcnts) of crystallized protosulphate of iron, (2FeO,S()^,7HO,) and mix them ill a small llask 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 i)ure binoxide of manganese, (MnO",) and would, therefore, if pure, peroxidize exactly the two e(|uivalentp, 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 inmiediately 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 4o'6 grains erf 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 insuflicient 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-lifiuor, as follows : Since 1 equivalent ( = 122'.5 grains) of chlorate of potash (=rKf),C10^) produce, under the influence of boiling chlorhydric acid, 6 equivalents of chlorine, as CHLOROMETEY. 333 shown by the equation : KO.CIOH 6IIC1 = KC1 + 6H0 + 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 Ali'Q 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 careluUy, drop by drop, from a glass alkalimeter through the tube funnel into the boiling hot solution containin<^ 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 tlie 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 2r8 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 (luring 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- l)liate, 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 unprofital^ly 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 clilorine, if we saturate the excess of chlorhydric acid employed by means of a solution of carbonate of soda, as in acidimctry, 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 tlie manganese, which will have been ascertained in the first jtart 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 alkalimetrical divisions contain exactly 53 grains (one equivalent) of it, and are conscfiuently capable of saturating exactly 3r)-5 grains (one equivalent) of pure chloriiydric acid, let us suppose that in order to saturate the excess of free acid left after tlu.' determination of the chlorine evolved by the manganese, it is found tliat Mt) alkalimetrical divisions of the test solution of carbonate of soda just alluded to have been required. Since 100 alkalimetrical divisions 33i CHLOROPHANE. or measures of carbonate of soda can saturate 36-5 grains of pure chlorhydric acid, tlie 140 divisions or measures employed represent, therefore, 51-1 grains of acid left in excess and in a free state, which being deducted from the lUO grains (contained in the 500 grain measures of acid of specific gravity r093 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 50 per cent, of peroxide of manganese as before mentioned; these will, therefore, have consumed 3G'5 grains of chlorhydric acid, which being deducted from the 489 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 npon consisted of Pure peroxide of manganese 21 'S = 50*00 Impurities unprofitably consuming chlorhydric acid - 12"4 = 28*44 Other impurities - - - 9-4 — 21 "56 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 215' 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 potasli, and the quantity neutralized, compared to the carbonic gas produced, will show by the ratio of 98 to 44, the amomit of acid unprofitably consumed. — A. N. CHLOROPHANE. A name given to some of the varieties of fluor spar. See pLroR 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 Chromatc of Potash is Potash 48-0 Chromic acid 520 100-0 These salts arc much employed in Calico Printing and in Dyeing, which see. The value of a solution of chromatc of potash, if it be tolerably pure, may be in- ferred from its specific gravity by the following table : — At specific gravity 1-28 it contains about 50 per cent of the salt. " " 121 " " 33 " " " " 1-18 " " 25 u II 1.J5 u a 20 " " " » M2 " " 16 " *' II (( \-\0 " " 12 " " 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. CIIROMATE 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 sohi- tion of the neutral chromatc 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 cliromate 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 5 1 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 5(X) 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 undeconiposed chloride of sodium and soda, 150 lbs. of })0wdered bichromate of potash are to be added, and the whole well stirred together, and finally washed. Liebig and AViihler 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 IROX. 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 4-5 ; 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 Var 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 New 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. 1 5. Sesquoxide of Chromium Protoxide of Iron Alumina Magnesia - . . . - Sihca --...- 3G-0 37 -0 21-5 5 54-08 25-C6 9-02 5-36 4-83 39-51 86-00 13-00 10-60 60-04 20-13 11-85 7-45 43-00 34-70 20-30 200 99-5 98-95 99-11 99-47 100-00 (1) From St. Dotninfro, nnalyzftil by Berthier; (2) from Riiraas, in Norway, nn.ilyzcd by Von Kobell; (3) from Baltimore, analyzed by Soybert; (4) cryslallizcd, from Baltimore, analyzed by Abiob; (5) ana- lyzed by Klaproth. 336 CHKOME 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 sil'ted. It is then mixed with one third or one half its weight of coarsely-bruised nitre, and exposed to a powerl'ul 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 aflSnity for the second atom of the potash, than the chromic acid does. The first great improvement in this manufacture was the dispensing with nitre, 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 1847 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 ; the 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 15 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 tlie 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 coiTverted 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 lime 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 .sliglitly reddens blue litmus paper ; the chromate of lime is hereby converted into bichromate ; chalk is now added, until the whole of the scsquioxide 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. 337 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. Anahjsis 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 mi.^ed 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. Tiie 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. Ghi'ome 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 bicliromate 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 tlie 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 sulplmric acid required, so that the solution is neither aifected 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 bo 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. Tlie 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 hy filtering a little of the mixture. The addition of some potash accelerates the operation. This consists in combining the sulphur with the oxygen of tlie chromic acid, so as to form sulphuric acid, which unites with the potash of the chromate into sulphate of potash, while tlie chrome oxide becomes a hydrate. An extra ((uantity of potash facilitates the deoxi- dizement of the chromic acid by the formation of hyposulphite and sulphurct of potash, l)i)th of which have a strong attraction for oxygen. For this purjjose the dear lixivium of the cln-omate of potash is sufficiently pure, though it should hold some alumina and silica in 'solution, as it generally does. Tlic 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 carl)onato of potash, not added in excess. By calcining a mixture of bichromate of potasli and sulphur in a crucible, chromic acid is also decomposed, and a liydratcd oxide may also be obtained ; the sulphur being partly ronverted into sulphuret of potassium, and partly into sulphuric acid, (at the expense of the You Tir.— 22 338 CHEOMIUM, 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 CItromium 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 precii)itate 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° Bcaume 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 with 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 lie added 1 lb. of common salt, and half a pound of concentrated sulphuric acid ; the liquid will now acquire a green color. To be certain that the yellow color is totally destroyed, n 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, redi.ssolved, 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. CIIRYSOBERYL, or GOLDEN" BERYL, is composed of alumina 80-2 and glucina 19-8 = luO. 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-S. 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, L^. 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 cry.stals (generally 8, 10, or 12-sided prisms) arc 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 89-'73, magnesia 50-13, protoxide of iron 9-19, alumina 0-22, protoxide of manganese 0-09, oxide of nickel 0-32 = 99 -eS. — 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, A'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 suftbcating 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. — II. 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 t)f the ancients. — H. W. B. CINCHONICINE. C""H-*N^0-. 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 2*70'. The product is pure sulpliate of cinchonicine. By a similar reaction quinine becomes converted into quinicine ; quinidine also is susceptible of a similar metamorphosis. — C. G. W. CINCHONIDINE. C"ff'N-0'. 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 Macaralbo. 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 alwaj's carefully re- moved from the latter. Some of the differences of properties on which processes for their separation may be founded arc 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 {xnlphurct) 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 cl.ay, bitumen, oxide of iron, &c. Cinnabar is of a cochineal red color, often inclining to brownish-red, and lead- gray, wich an adamantine lustre, approaching to metallic in dark' varieties, and to dull in Iriable 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 = 8'90. 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 11,544 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. Sec Vermilion. — II. W. B. CLOVE OIL. (C'°II'^0\ Siin. Euqmic acid, Caropkyllic acid.) When cloves are distilled with water, a large quantity of oil passes over. It has been examined by Dumas, Ettling, Bockmann, Stenhouse, Calvi, and, more recently, 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 Carbl'retted Hydrogen. The potash soiu- 340 COAL. 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 57 "•2 F. is 1-0684. On analysis it gave : — Greville Williams. Carbon - Hydrogen Oxygen - 73-1 73-1 7-7 7-6 19-2 19-3 100-0 lOO-O* Calculation. C'-"' 120 73-17 H'« 12 7-32 0^ 32 19-51 100-00 The density of its vapor was found to be 5-86, Theory requires 5-67. 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. 1854. 1S55. 1S56. 185T. Northumberland and Durham 15,420,615 15,431,400 15,492,969 15,826,525 Cumberland .... 887,000 809,549 913,891 942,018 Yorkshire - - - - - 7,260,500 7,747,470 9,083,625 8,875,440 Derbyshire - - - - - Nottinghamshire - - - - 2,406,696 813,474 2,256,000 809,400 [3,293,325 3,687,442 Warwickshire . . . - 255,000 262,000 835,000 398,000 Leicestershire .... 439,000 425,000 632,478 698,750 Staffordshire and Worcestershire - 7,500,000 7,323,000 7,305,500 7,164,625 Lancashire . . - - - 9,080,500 8,950,000 8,950,000 8,565,500 Cheshire 786,500 755,500 754,327 750,500 Shropshire 1,080,000 1,105,250 752,100 750,000 Gloucester, Somersett and Devon 1,49-2,366 1,430,620 1,530,000 1,225,000 Wales 9,643,000 9,677,270 9,965,600 8,178,804 Scotland . . . - 7,448,000 7,325,000 7,500,000 8,211,473 Ireland .... 148,750 144,620 136,635 120,630 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 di.'^tribtition 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. Lirfnite of Bovcy-Heathficld. — Lysons {Marina 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 exi.sting 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 neiglil)or- 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 Bcvhe. Bideford Anthracite — The beds of Anthracite stretch across the country from Barn- staple Bay, by Bideford and Averdiscot, towards Cliittlehampton, a distance of about COAL. 341 ir,() 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 ; fl, sandstones ; 6, shales ; c, cuhn 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 (having a thickness of) Smith Coal " Little Delf '* Park End High Delf " Stakev 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 " 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. — Mnclaicchlan, Geological Transac- tions ,vol. 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 are 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 5 beds of coal. Lower shales 1,.565 feet, with 36 beds of coal. Farewell Rock 1,200 feet. ft. in. 1 2 2 6 1 8 3 n 2 6 1 1 1 9 4 2 2 1 9 2 9 2 6 5 2 1 4 6,290 SocTH 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 wliich appoMrs 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 tlie field the series is found to lie on proportions only loss gigantic. The most general view which can be afforded seems thus, giving the true coal measure about 8,000 feet : — feet. Llanelly scries, with several beds of coal 1,000 Penllergare series of shales, sandstones, and beds of coal, 110 beds ; 26 beds of coal 3,000 342 COAL. Central series, (Townhill sandstones of Swansea, Pennant grit of the Bristol field ;) 62 beds, and IG beds of coal Lower shales, coals, and iron-stones, (Merthyr ;) 2fi6 beds, 34 beds of coal Abundance of iron-stone beds and unionidce occur. Farewell-Rock and Gower shales above ; the carboniferous limestone below, 246 812 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. — Tliis district includes the small coal-field of Coalbrook Dale, and that of the plain of Shrewsbury. The Coalbrook Dale field, according to Mr. Prcstwick, has some remarkable features. {Geological Transactions.) Perhaps tliere 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 cast-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 V 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, eiglit inches thick, is sulphureous. — Phillips, Prcstwick. Staffordshire. — T7ic coal-fcld of South Staffordshire, which has been described by Sir. 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 Gre.at 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 Coalfield. — 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 IS'orton church. Derbyshirf, 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 ; " soft " coal, where the cleat fissures are numerous, and broken by cross cleat. In respect of the qua,l'ity. 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 iirocess. — Phillips's Manual of Geolofjxi. The names by which the more important bods 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, Canister 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. 343 Eureka coal Stocking coal Woodfield coal - Slate coal Nether main coal Fourfoot coal The Earl coal - In the Coleorton district — Heath End coal Lount coal Main coal - Thickness of beds. 4 to 6 feet. 6 to 7 " 5 3i to 4 " 14 to 15" 4 to 5 " 4 ft. 6 in. 9 feet. (3 beds.) 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 WooUey Hooton-Roberts, &c. Furnace coals Upper coals Middle coals - Intermediate coals Iron-stone coals - - Barnsley thick coal. ( Rock of Horbury. " \ Middle coals. j Silkstone and Flockton beds. " \ Low Moor coals. Flagstone rock of Woodhouse, Bradford, Elland, Peniston, &c. C 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. Furnace coals of Barnsley, &c. including the eight or ten feet scam. Rock of Horbury and Wentworth House. ! 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. — Ilei/wood. 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 ail 93 feet of coal. The series is divisible into throe 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 v.aluable 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 Walk:s. — Piintuhire 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 Conybcarc. 344 CO^VL. 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 ui 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. AVovkington. Maryport. Bannock band. Maiu band. Six-quarter coal or Low- bottom seam. lloorbunks. Main seam. Hamilton seam. Ten quaiters. Cannt'l and metal scams, (divided with shale from 2 feet to 5 fatlioms 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 Sliotley 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. Illr/h main coal - 6 Unknown Strata and thin coals - GO Five-quarter coal - Metal coal - 1 6 Strata and thin coals - 30 Stone coal - - - 3 Strata 83 Yard coal - - - 3 Main coal Strata - 90 Bensham seam . 3 Mandlin seam Strata with several variable beds and some lavers of mussels - - 150 Low main or Hutton Loxo main coal - 6 seam Strata - 200 llervci/s seam - 3 Beaumont seam - Strata - 300 Brockicell seam • - 3 Brockwell seam - Strata above millstone gi it - 200 On the Wear and Tyne :- Ft. In. Ft. In. 3 9 to 6 9 5 6 to 6 4 C to 6 4 6 to 6 6 3 to 6 3 to 6 — PJdllips. 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 scam of the Wear. The Beaumont or Hervcy scam is the Townley seam of the Townley colliery and the main coal of Wylam colliery. At Ilet- 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-coat seam and stone coal seam of Sherrilf 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 Pontsss, and the main coal in Auck- land. Again the Cramlington five-quarter seam di\ides and forms the .=ix-quarter, and the five-quarter at Shcrriff Hill the Br.a.ss 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. that 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 Andrev>"s 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 tlie commencement of the basaltic rocks, forming the general floor and border of tin's 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, imattain- 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 Ballycastlc 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 tlie 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 coal 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 Paser 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 appeal's 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. Tliis coal dilfers essentially from that of any known European formation, but hears 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 innnbcr of coal basins in the world ; the total nmnbcr must, how- ever, amount at least to from 250 to 300 principal coal-fields, and many of these are subdi- vided by the distm-bed 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, I'rance, Spain, (in the Asturias,) Germany, (on the Ruhr and Saare,) Bohemia, Silesia, and Kussia, (on the Donetz.) Bklgium. — 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 arc 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 flume and smoke, not giving out an intense heat, and having a somewhat disagreeable smell. There are nearly fifty scams 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 il. 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 2G0 fathoms, inasmuch as the deeper they go the more destructive and unmanageable will be the effects of the pressure." — Tlie Government Miyiing-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 : — \. 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 of 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, thefe 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. Hard coal, short flame. Forging or gaseous coal. Gaseous coal, long flame. Small coal, long flame. Lignite, Stipite, &c. The total of indigenous fuel extracted, according to the State returns, is 47,222,743 metrical quintals of 10'14(J5 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 ■ — I Saxony. German States, i Bavaria. Prussian States. ( Duchy of Flesse. in Westphalia. !La Ruhr, ii Sile.sia. 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 Saarbruck, a Rhenish province belonging to Prussia, has thus been described by Humboldt, chiefly from a communication received from M. Von Dechen : — " The depth of the coal measures at Mont St. Gillcs, Liege, I have estimated at 3,fi."iO feet below the surface, and 3,250 feet below the sea level. The coal basin at Mons lies fully 1,730 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 20,650 under the level of the sea." The coal of the valkij 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 50,0U0 tons annually are produced from this valley. Coal is found in Wurtemburg, but not much worked. In Saxony arc 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 Thurmgcrwald 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 coul is worked at Helsingborg, at the entrance of the Baltic. Dknmark. — 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. RcssiA. — 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. Tdrket. — Coal is found bordering on the Carpathian mountains, in Servia, Roumelia, and Bulgaria. The coal of Heraelia, 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 toucliing 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 o? the Alleghauies ; the coal-fields of Illinois, and the basin of the 348 COAL. 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 contribut-e greatly to the riches of vaiious States. The Alleghany or Appalachian coal-field measures V50 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 -t 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 argiUactous car- bonate.) The coal-field of Kentucky extends over about 9,000 square miles. In Western Virginia there are several coal-fields of vaiiable thickness : one, 9i 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 afibrds on an average at least 6 feet of coal. The Marykmd district is less extensive, but is remaikable as contain- ing the best and most useful coal, which is worked now to some extent at Frcstbury. 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 scams 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 facilitj^. 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 im]>ortance. Taylor states that at least one-eighth of the State of Missouri is overlaid by coal meas- ures. G,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 8 coal-fields, occupying in all no less than 8,000 square miles ; the latter exhibits several very distinct localities where 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 coj)per ores, and coated by green carbonate of copper. The coal is generally in thin seams lying horizontally. It is chiefly or entirely bituminous. Nov.\ Scotia possesses three coal regions, of which the northern presents a total thick- ness of no less than 14,570 feet of measures, having TO 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 difterent 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. NKWForxDLANn CoAL-Fira.D. — This field is estimated at about .'"),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 35fi 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- val.s, along a space of 1 50 to 200 miles to the north-ea.st. Greknland. — Captain Scoresby discovered a regular coal formation here. At Ilasen Island, Bovey or brown coal has been found, and also at Disco Island on the western coast. COAL. 349 Arctic Ocean. — At Byara 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. Rl'ssian 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, Xorth lat. 4H', and West long. lOTi'. "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 sonie 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, Xorth 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, " Texa^i, its Geoyrapfuj, d'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. Yesezuela 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.V 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 asphaltura 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. dc la Beche, Trans. Geological Socieli/ 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 tlie conditions which have been described, but these arc due to disturbances which have taken place either since the formation of the coal, or during tiie period of the actual deposition of the coal. That coal is derived from tlie 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 mucli uncertainty ; and the conditions under which the change is brought about arc 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 wliich vegetable matter is deposited, the layers, according to circumstances, vary- ing in thickness, which become covered with nmd or sand, and were thus entombed ; the decomposition and disintegration breaking up the vegetable structure, goes on for ages. 350 GOAL. Microscopic observers assure us that they are enabled to detect ligneous structure in the bituminous coal. Mr. Queckct has given a great number of drawings in proof of this, and he refers the coal to the icoody 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 wlien 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 stigmaricB, and are flattened and com- pressed, those singular plants of the underclay (the stigmariai) 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 500. Lindley 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 Lepidodendronx. These, with E(jidsetaccw, Colamites, Asterophyllites, Sic/illaria, of which about thirty-five species are known with their roots, Stigmariw and Conifera, make up the remarkable flora which have been preserved to us in our coal series. Trees and humbler plants in great variety arc found in the carboniferous sandstones and shales, and in the coal itself, but it docs 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 subxtitnted by silica, or sometimes by carbonate of lime, and sometimes bv iron. Sir Charles Lyell has carefully examined the phenomena, now in progress, of the great delta of the Mississippi, and ho perceives in them many facts which fully explain, to his mind, the progress of coal deposit. It cannot, however, he 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 suliject, says : " There is no necessity to enlarge tipon 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 ligncou^parts of the plants, and from the unanswerable identity of the carbonaceous substa7ice, 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 cjuite probable that hereafter the reason of the variations to which both are suliject, whether dependent on the original nature of the plant or produced by unequal exposure to decay after inhumation, or meta- morphic subseeiuent 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, wc should have the exact conditions for the transformation of vegetable matter into coal." — 77/c Stiident''s Manual of Geology. Much stress has been laid upon the fact that we have brown coal still retaining all the unmistakable characters of wood, and the apparent passage of this into true coal. Giippert states that the timlier in the coal mines of Charlottcnbrunn is sometimes con- verted into brown conl. 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 m:ide by him, this conversion, by the separation of marsh gas and carbonic acid from the ligneous fibre of oak wood. — Bixehqf. The same authority says : " This conversion of wood into coal may take place in four different ways, namely : " I. 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. Oxygea Authority. Oak Wood 52-53 5-27 42-20 Gay-Lussac ' and Tlienard. 1 Decayed Oak Wood - - - - 53-47 5-16 4r37 Liebig. 1 Fossil Wood 57-8 5-8 36-4 Regnault. iTurf 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 Walcliow - . . . - 80-3 10-7 9-0 Schrotter, Peat coal 80-7 4-1 15-2 Baer. Coal 82-2 5-5 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 laminte 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 laminse 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, {linger.) Fuel 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 da>/ — upon which the coal is found, or were drifted to it, there must have been long periods daring 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 F.\ults.) The difficulties are mainly the facts — 1. That the evidence is not clear that any thing like llgiieons structure can be detected in coal. 2. That tiie tvoody matter found in coal is never converted into coal, although sometimes it appears as if the bark was so changed. 3. That tlie 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. 5. 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. 352 COAL BRASSES. Wc do not intend to answer any of those difficulties, but to leave the question open for I'lirther examination, merely remarking, in conclusion, that there can be no doubt of the vegetable origin of coal ; the only cjuestion 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. In 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. Wc 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, sulpJnde 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 jirotoxide 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 arc 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, Mhen 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. 68-71 59-73 17-74 0-42 0-37 - 9-36 11-80 14-19 11-80 15-55 12-06 0-22 trace 49-72 0-17 0-23 trace 8-87 9-80 6-10 — 2-70 99-55 100-18 99-81 Carbonate of iron Carbonate of manganese Carbonate of lime Carbonate of magnesia Iron pyrites Phosphoric acid Coaly matter Clay .... " 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 di.strict. 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. OOAL-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 : — Cannel (Boghead) Cannel (Wigau) • Coal - Oil Resin - Peat - Wood - Percentage of Percentaue of Percentage of Carbon. Hydrogen. Oxygen. 80-35 11-21 6-71 85-95 5-75 8-14 88-15 5-26 5-41 78-90 10-97 10-18 79-47 9-93 10-59 60-41 5-57 34-02 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 at/t. 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 continued afterwards to glow, until nearly the whole of the carbon is consumed. If, however, the application of heat lie made without access of air, by inclosing the materials, for instance, in an iron retort jirovided 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 containing several solid Vol. 111.-23 354 COAL-GAS. hydrocarbons partly in solution and partly in suspension ; whilst the other one consist i 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. Chemical Formula. Hydrogen H Light carburetted hydrogen - - - C^H* Carbonic oxide CO defiant gas Propylene Butylene - Carbonic aaid Sulphuretted hydrogen C'H* C'H' C'H' CO' SH Aqueous layer : Oily layer : — Nitrogen N II. Liquid. Name. Chemical Formula. -Water HO Bisulphide of carbon .... CS' Benzol C'=H^ Toluol C"H« Cumol C'*H"» Cymol C^^H" Aniline C'^H'N Picoline C'H'N Leucoline C^H'N Carbolic acid C'^^O' Other hydrocarbons CnHn* " " CnHn + 2 " " CnHn— 6 III. Solid. Name. Chemical Formula, In aqueous layer : — Carbonate of ammonia .... NH^OCO* " Hydrosulphate of sulphide of ammonium - NH'S + HS " Sulphite of ammonia .... NH^OSO' " Chloride of ammonium .... NHTl In oily layer :— Paraffine C'^H" Naphthaline C'°H' Paranaphthaline C=°H" Pvrene C=°H= Cbrysene C^'^H'" 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 arc 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, (■). 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 nrrjand consists of a hollow annulus, (see fir/. 101,) from the upper surface of which the gas issues through a number of small apertuies, which are made to vary in diameter from ''30 of an inch to */f,o 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 "IS 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 diainctur of 4 an inch, and for 20 orifices, 1 inch. The pin holes should )je 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. Sec Jig. 162. Guise\s argajid contains 26 holas in a ring, the inner diameter of which is '6 inch, and the outer diameter 1-9 inch. Like the Winfieid burner, it has a metal button + an inch in diameter, and 1 inch above the annulus. The glass chimney, Avhich is cylin- drical, is 2 inches in diameter, and 6 inches long. Leslie's argand consists, as is seen in the figure, {fig. 1 64,) of a series of fine tubes arranged let in a circle, by which a more uniform admixture of air with the gas is effected. A suflicient current of air for all these argand burners can only be oljtained by the use of a glass chhn- 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, hg Mr. A. Wr ght. 1 Foot 1} Foot 2 Feet | ii Feet 3 Feet 3j Feet 4 Feet 4} Feel per Hour. per Hour. per Hour, per Hour, per Hour. per Hour. per Hour. per Hour. Scotch Fish-tail, No. 1 : — One foot := candles - - 4-75 502 " = grains of sperm 595-0 602 Scotch Fish-tail, No. 2 :— One foot = candles - - 505 5-7T 5-95 5-S4 5-53 " = srrains of sperm 6060 090-0 V14-0 7000 6G3-0 Guise's Argand:— One font = candles - - . 1-OS 185 812 4 85 4 95 5-77 C-74 " = grains of sperm ■ - 129-0 222-0 374-0 582-0 594-0 692-0 808-0 366 COAL-GAS. s fe 5b !o *s a >o f^ * tH © •* K5 *3 s -^ C3 00 00 1^ ^ CO CO 00 lO 10 Tf (M ir- CO Ci CI 00 Oi p^ ■^ C5 CO CT> T)! rH CO 00 1—* i.^ 00 to ■V •^ '^ CO *s to •* M< M to ■* rH 00 t^ 00 t^ >n CO c^ ■* <* CO rH CO rH * Tjt CO *: d C5 Oa a rH rH CO -M j^ ^ ir- -+ C rH f^ ^ Tf CO to CO to C5 rH CO •^ -^ \a m IQ »o tH -^ji 01 to 00 ^ r- t~ to ■* rH CS CO rH CI CO >a 10 CO 05 Tj< OS -* CO CO CO eo rH 00 CO CO £- Ci CJ 00 •* >o 10 CO -^tl 05 1~- CI ^_i C5 t- t~ t~ 1-H 00 to t- to C 00 t^ CO 10 ■* to Ti< •* CJ CO CI 10 rH ,-1 •^ JO to Oi <-< CJ CO »i Tl< ^ CO 00 '"' o to CO CI to rH r- e> K3 10 to 00 Ttl j:~ CO CO ,-( rH CO CJ h I-H rt o rH CO y—t ci •* i- ' • 00 I-H 10 to 03 1-H CO -f 10 to 00 I:- CO C5 ^ C-] rt ^=JV-OlO SJ IB "2 .S '^ ^ .5 '^ "^ d :2; ^5 .= J^ := a '5 ' a 5 _r a '5 ■u .a ■o" |'£li:'-S,H-i^H "5 s a '5 ei t- •- ej t- — c3 1- c3 s- a ci t- -1 tt - t. rt 1. tx: rt tx 5 y tc M rt "5 II II "sl II lll^ Cl ,-~ --H jr Do b .£ S .5 2 tc 11 1 II j II II 1 II II So So II 11 ' tl. II 11 to a '■Xi i t-. ^^ :; t. — IE " 3 " tn a "^ a go go a a ^ t-3 rt po a a i>:3 1-4 E c> a. OJ " COAL-GAS. 367 Table III. contains the results of Mr. Barlow's experiments on gas produced from a mix- ture of Pelton, 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. 5 bat's-wing. 3d. A common argand, with 15 large holes in a ring So inch diameter, and a cylin- drical chimney glass 7 inclies high. 4th. A Platow's registered argand, with large holes in a ring, '9 inch, with inside and o'.Uside 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"o inches high. 8th. A Guise's registered shado^vless 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 IIL Burner. Rate of Consumption per Value of Cubic Foot in Standard Candles per Hour in Cubic Feet. Grains of Sperm. Cubic Foot. No. 2 4-9 289-0 2-4 " 3 5-5 343-0 2-85 " 5 5-0 374-0 3-11 " 6 6-5 337-0 2-8 " 8 5-5 350-0 2-91 " 1 6-5 276-0 2-3 " 2 5-0 290-0 2-41 " 3 5-5 341-0 2-84 " 4 5-5 348-0 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. Fi(/. 105 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 b, c ; the latter must be 4 to 6 inches longer than usual. (Z 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. ff is a 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 f should l)e of such a length as to reach the level of the apex of tlie flame. The action . of this burner will now be sufficiently evident. When lighted, atmos- I)heric air can only reach the flame by pii.'^sing duwnwaids tlu-ough the space between the cylinders yand 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 pa.ss!ige of this heated air over the upper portion of the argand burner, also rai.ses the temperature of the gas considerabl}' before it issues from the burner. 165 368 COAL-GAS. Thus tlie gases taking part in the combustion arc liiglily 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 carbon ; but, no doubt, partly also to the heat being suHieienllv high to cause a deposition of carbon from the light carburetted hydrogen ; thus rendering this latter gas a contributor to the total ilhuninating effect ; whilst, when burnt in the oidi- nary manner, it merely performs the functions of a diluent. The following are the results of Dr. Franklaud's experiments with this burner : Light in Sperm Canilles, each burnins liO grs. pci' Hour. 13-U candles. 15-5 " I. Argand burner without external cylinder. II. Same burner with ex- ternal cylinder. Kate of Consumption per Hour, r 3-3 cubic feet 3-7 1 4-2 (2-1 2-6 2-7 3-0 3-3 17-0 13-0 15-5 16-7 19-7 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 eijual amount of light ; and also that it produces a gain of 67 per cent, in light for equal consumptions. Faradnfs roifilatinrf hnriicr. — 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, y?*/. ItJO, a, fitted with the usual gallery and chimney b b. 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 c. f is the tul:)c convey- ing the gas to the argand ; ff <^ is 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 coml)ustion 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 which 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 peculiaiity of which consists in the use of a separate tul)e bringing air to the flame from the same place, outside the building, to which the products of the burner arc 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. Ox THE Estimation of the Value of Illuminating Gas. There are two methods in use for estimating the illuminating value of gas, viz. : — Lst. 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 eiii])loyed is usually a spermaceti candle, burning at the rate of 120 grains of fii)erm per hour. A spermaceti candle of six to tlie pound usually liuriis at a somewhat quicker rate than this ; but in all cases the consumption of sperm Ijy 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 sperm was at the rate of 130 grains per COAL-GAS. MS 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 tlame 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 2r7 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 iiill 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 '/» 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 in candles. Thus, if ecjually 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 — — - = • =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 Bunseii'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 ga.8 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 tlun 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 e(iuality 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 poitions of the screen will become distinctly visible ; the spot in the centre appearing comparatively opa(|ue 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. 1G7) from the centres of sockets at its ends A B. 2. An upright pillar C. 3. A candle holder d. 4. A mahogany slide e, having a metal socket F on its top, to hold the circular frame o, and a small pointer in its front. 5. A circular metal frame o, made to hold a prepared paper. 6. A blackened conical screen ii, dimini.-^hing 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.— 24 370 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 '/lo 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 Voo 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 %oo of a cubic foot in Veo of an hour. Multiplying these quantities Vjy 60, we have Veo %oo x 60 = ^'""/eoo = 4^ cubic feet and Voo X 60 = 1 ; so that 4i 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 170 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 fg. 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 8J inches long, 1 J inches broad, and If inches deep. The bottom of this cavity is roimdcd, with the exception of a portion at one end, where a surface, 1 incli broad, and 1 \ inches long, is made perfectly flat, a piece of vulcanized India-ruljber, Vio of an inch thick, beiii"- firmly cemented upon it. Two end pieces n n, f of an inch thick, 3J inches broad, and .5 inches high, are fixed to the block a ; these serve below a.s .supports for a, and above as the ends of a wider trough, which is formed by the pieces of plate glas.s c c, cemented into a and B B. The glass plates co are lOJ inches long, and 4 J inches high ; they are slightly 372 COAL-GAS. inclined, ?o 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 bv 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. h 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 SO 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/r/. 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 d d, with its contents. This cylin- der is 36 inches long, and 4 inches internal diameter ; its lower extremity is firmly cemented into an iron collar r, the under surface of which can be screwed perfectly water-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 e, e, e, are screwed, and * Those balls, wliich should bo of tho size of a lar^e pea, are required constantly in operations upon pases: they are readilv prepared, when the substance of which they arc formed is fusible by heat, as chloride of calcium or caustic potash, by meltins these materials in a crucible and then pouring them into a small bullet-mould in which the curved end of a platinum wire has been placed ; when quite cold tho ball attached to the wire is readilv removed from the mould. Coke bullets are made by fillinR the mould containinc the platinum wire with a mixture of two parts of coke and one of coal, both tmely 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 e, 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, e, e. f 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 «, 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 I. f 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,s be accomplished. The absorption tube I is sup- ported by the clamp »i, and con- nected with the capillary tube k, by the stopcock and junction piece / 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 tlie 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 /, and the stoppered funnel i, and placing the cock f in such a position as to cause the tubes f ii to communicate with the supply tube G. On now slightly turning the cock r/, the mercury will slowly rise in each of the tubes f and ii ; when its convex surface exactly coincides with the ninth division on f, the influx of metal is stopped, and its height in Ji accurately observed ; as the tenth division on f corresponds with the zero of the scale upon ii, 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 tlie introduc- tion of a few drops into each, through the stopcock /, and the stoppered funnel /. The three tubes being then placed in communication with each other, mercury is poured into g until it rises into the cup i, the stopper of which is then firmly closed. When the mercury begins to flow from I, that cock is also closed. The tubes f and ii are now apparently filled with mercury, but a minute and imperceptible film of air still exists between the metal and * This instnimpnt may be obtained from Mr. Oertling, philosophical instruincnt-niaker, Store Street Tottenham Court Itoad. 374 COAL-GAS. glass ; this is effectually got rid of by connecting f and n with the exit tube h, and allow- iu" the mercury to flow out, until a vacuum of several inches in length has been produced ill both tubes ; on allowing the instrument to remain thus for an liour, the whole of the fihn 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 I and the stopper i whilst G is full of mercury. The absorption tube i being then filled with quicksilver, and attached to I 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 ojjcrations are necessary : — I. Estimation of Carbonic 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 pioper 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 Oxygkn. This fas 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 wJil 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 lif'ht is allowed to have access to the mixture ; but the tondensation 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 liglit. 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 versa, 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 l)y which the estimation of the luminiferous constituents can be accurately effected is anhj-drous 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 liqmd for one minute ; it is then withdrawn, leaving as little superfluous acid adher- ing to it as possible, quickly plunged beneath the quicksilver in tlie trough, and introduced in?o 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: tliis 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. 375 a manner as to prevent its being readily drawn out ; the ball should then be put in a warm place, and allowed slowly to dry, 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 rc- phiced 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 diflerence 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 syial.vses of the same gas, the percentage of luminferous constituents seldom varies more than O'l or 0-2 per cent. IV. Estimation of the Nox-Luminiferocs 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 I of an inch internal diameter; the thickness of the glass being not more than Vio 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 : thfs 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 proi)ortions 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. Tlie 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 0X3'gen, 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 carl)uretted hydrogen, and carbonic oxide respectively by x, y, and z, we have the following equations : X -I- y 4- z =r A y-l-z = C From which the following values for x, y, and z are derived : — x = A — C 2B — A y z = C 3 2B — A 876 • COAL-GAS. V. Estimation of the Value of the Lcminiferous 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 at!brd 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 luminifcrous powers of these hydrocarbons, that the greater the amount of carbon contained in a given volume, the greater will be the ([Uantity 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"oG volumes, it is clear tliat this amount of carbon vapor nuist 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 eifevtcd ; for if we ascertain the amount of carbonic acid generated by 100 volumes of the gas in its original conditicm, 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 lumiiiiferous 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 valuaV)le and useful information is gained. Analysis of Coal-Gas with Frankland and Ward's Apparatus. — Introduce a few cubic inches of the gas into the tube i, frj. 173, and transfer it for measurement into f, by open- ing the cocks II' 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 / is shut, and / turned, so as to connect f and ii with h. Mercury is allowed to flow out until a vacuum of two or three inches in length is formed in ii, and the metal in f is just below one of the divisions ; the cock / is then reversed, and mercury very gradually admitted from o, 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 the 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 ii 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 ii 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 iipon the volumes or pressures, no barometrical ol)ser- vations are requisite ; and as the tension of aqueous vapor in f is exactly balanced by that in II, the instrument is in this respect also self-correcting. Two^r 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 n Vjy cpening tlie cock g, the gas returns into i tln-ougli II ', and there coming into contact with an extensive surface of caustic potash solu- tion, any carbonic acid that niay be present will bo absorbed in two or tliree minutes, and the gas being passed back again into ii for renieasurenient, taking care to shut / belbre the caustic potash solution reaciics I ', the observed diminution in volume gives tlie 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 j«neasuring the gas in F. Tiie next stop 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 mercur}-, 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 l.V 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 luminifero-us 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 t!ie 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 qualilica 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 .'^liglifly viscous, and at the same time undergoes rapid oxidation. AVrought-iron is a still bitter 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. Very various forms of retort have been employed at different times in order to secure, as far as possible, the conditions just enumerated. Cant-Iron Retorts. — The chief forma of the cast-iron retorts are : First, the cylindrical, fig. 174, u.sed in the Manchester Gas Works, 12 inches diameter, and <'> to '.• feet hmg ; Second, the elliptical, 18 inches by 12 inches, by (J to 9 feet,///. 175; Third, the car I7r. 177 (X) 378 COAL-GAS. shape, fg. 176, no-w little used, 2 feet by 9 inches, and of the same length as before ; P'ouith,' the D-shaped retort, fg. 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. 178 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. 179 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 mouthj)iece a a, fig. 179, can be securely bolted. The mouth- piece is provided with a socket b, for the reception of the staiidpipe, 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 detained. 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 manufocturer 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. — ^fr. 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 higli at the crown of the arcli. About 1 ton of coal can be worked off in these retorts in 2i 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. Earthevware, or Clay Jieforts. — These are usually of the D shape, although they are occasionally made circular or elliptical. Their dimensions are about the same us those of the cast-iron retorts commonly used, but their walls arc 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 duraljility 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 lire-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. 37? from dififerent 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 fur the higher purposes of manufacture, being e(iually 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 -i- to upwards of 1 per cent. " The works of Messrs. Cowen & Co. are among the most e.\lensive 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 1S4-1 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 \\%;v\\XV^^i\v' - ;\-}&;s\- ■ \V%«>^<^\\X?^«i3?^ 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. Ketorts of less creditable appearance are exhibited by Messrs. Hickman & Co. of Stour- brido-e, 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 reciuire 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. ISO is an elevation of Mr. "Wright's plan for a range of long clay retorts. Fij. 181 shows the plans and sections of the setting for these retorts. 181 COAX-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, 7 feet long, 3 feet 2 inches wide, and 14 inches higii 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 Ret'oluing Web Retort. — This retort, 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 ; h is a wob 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 tiues 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, tliat the coal, which fills upon the wel> 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 hcatid 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 1 2,000 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 considei-ahly greater tlian that of the retorts in ordinary use, yet the dcstructil)le 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. Thk Rf.frigkratort 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 iu winter, whea it is advisable to maintain a heat, relatively to the external air, greater than in sum- mer. The gas leaves the retort by the sta7idpipcs a a a, fiff. 183, which are of cast-iron, 5 inches in diameter at their lower extremity, and :?lightly tapering upwards. Some of the least volatile products of decomposition 183 nnann /!S A I 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 hijdraulic main, which is shown at B, /?^. 183. It cousists of a cyhnder 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 L^^^fe^^^ drawing. The diameter varies from 12 i^--^^--^rLJsc_---%LJ, to 18 inches, and the recurved extremi- ties of the standpipcs {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 n rf aEIS^fidts UaJ pJ^-l VJ-^-T- JN-^-^ 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 condense); the office of which, as its riaine 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 lorms, 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 Jiff. 184. a A a a are 5 double concentric cast-iron cylinders, throu^di wliich the gas is made to circulate in succession by means of the ticpipes b b b b, whilst the inner cylinders being open above and below, a current of air, set in motion by tlieir 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 I'rom the drawing, and require no further descriptiom 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 C[uantity of gas generated iu 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 from these, it is passed through a scrvbber d, (Jiff. 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 luminifcFous hydrocarbons, its use is objected to by Mi-. 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. 77ie 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 increa.'^ed 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 Jiff. 185. The axle a is reduced at eaeli 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 tlie width of the annular space ; the box at one end is fitted with a stuffing-box, through which the axle passes for the application of the driving power. T'pon motion being given to the axle, the sliding pistons bb are carried with it.' These sliding pistons are furnished at their ends with cylindrical pins which ]irojeet and lit into cylindrical holes bored in the guide blocks c c, which fit into annular recesses i) in the end plates, and keep the slides in contact with the cylinder. The slides are fitted with me- 'tailic 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 Pcrification of Coal-Gas. Fiqs. 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 fy. 187 is another elevation, also partly in section, of the same, a is a hopper, into which the dry lime is fed ; b is a damper, or sliding door, by which the supply of lime can be regulated ; c is a .'iheet metal tube, containing the worm or screw d, the axis of which is supported at one end by the stuffing-box f, and at the other end by the bearing /. A slow revolving motion is given to the worm d from the driving shaft fj, )jy means of the bevel wheels A, upright shalt i, worm j, and worm wheel l\ fixed on the axis of the worm. The lime in the hopper a, is kept in motion by the screw n, which is turned slowly round by the worm g, the worm wheel o and bevel wheels //, one of which is fixed on the screw n. The tube c'is open at <■', to admit the dry lime from the hopper a, 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\ y h 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 »«', and are revolved speedily by the strap and pulleys X. These agitators serve to increase the action of the washing fluid contained in the tiibe I, bv 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 7, to the chamber >•, from whence it passes along the tube /, as shown by the arrows, to the chamber .? ; 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 «;, to the gasometer. COAL-GAS. 385 186 ■ '■ r, i i A / : A AWAx"* fi n n •"■• '"^ n 'i f :;4{_EE±CE^r - t'T'-TSfp ^ ^ ^^}^ ^ ^^u^^:::^:::;^; It will be apparent, as the gas passes along the tube I, containing the agitators >«, which are caused to revolve speedily by the motion given by the straps and speed pulleys x, that the washing fluid, which is passing regularly through the siphon y, and running into the chamber s, and along the tube I, into the chamber r, keeping the level as shown by j b, is caused to be re- volved into a centrifugal motion round the tube I, by the two paddles z, placed upon the circular perforated plates, secured upon the shaft ??2, which arc set to an angle, thereby causing a counter-motion from left to right of the tube I, 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 d, and as the cross pieces d' are set to an angle, as shown in fiff. 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 c" ; 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 d, the number of threads upon it, the length and diameter thereof, must be made to suit the quantity of gas to be purified per hour. The lime which drops into the chamber t, may be removed therefrom through the manhole w. Mr. Lees states that a considerable saving is effected in the lime, owing to each particle or atom being kept in mo- tion, and falling repeatedly through the gas in its passage . from one end of the tube to the other, and that there is also a great saving in labor. Another form of wet purifier, which might also be advantageously used as a scrubber, or as u naphthalizer, has recently been invented by M. Colladou of Geneva, and is now iu Vol. III.— 25 686 COAL-GAS. 188 ■ ^^~" '■■' _~)ii I ^ .:■...-■ r . •'~ use in the gas manufactory of that city. This apparatus, as shown in vertical section in _/?//. 188, consists of a section of a very obtuse cone a', the angle of incHnation of which is 164°. Its upper and smaller end is joined to a metal cylinder a, placed on the same axis as a', and about its own diameter in height. At top it is closed by a cast-iron plate k, through which the axle c passes : the latter communicates a rotary motion to the cylinder and cone a and a'. It is inclined 8° from the perpendicular, and rests upon the steel point of the centre pin b', whilst at top it carries a pulley by which a circular motion is communi- cated to it. a a are a series of metal discs which stand vertically to the inner surface of the cone a', with spaces of about one inch between them. The discs are arranged concen- trically, and have spaces corresponding to the quantity of gas which has to pass through them. They are from 5 to 7 inches long. As the axle c and cylinder a are not vertical, but somewhat inclined, one side of the cone a' will, during the revolution, be in a nearly horizontal position, whilst the opposite side will be immersed in the liquid to the extent of about 16'. The whole of this mechanism is enclosed in a sheet-iron lid B. The centre pin b is attached by a cross-bar to the lower edge of b, whilst the axle c is supported by d, whch is also attached to b. d' d' is a water joint permitting of the free motion of c. The lid B thus contains the whole of the washing apparatus, and it is held in its proper position in the trough c by lateral attachments, d is the inlet pipe opening into the cylinder a, from which it has to make its way through the discs a a to the outlet e. This apparatus gives no sensible pressure, and requires a very small motive power. 189 190 Fig. 189 represents an arrangement of four of the dry purifiers, worked by a central valve, as used at the present time in most large gas-works ; it is the inven- tion of Mr. Malam, and is described in Mr. Peckston's treatise, a, b, c, d, are the four purifiers connected with the central valve E in such a way as to permit of three of them being at work whilst the COAL-GAS. 387 fourth is emptied and recharged. The outer case of the central valve e, is a cylinder of cast- or wrought-iroD, 5 to 6 feet in diameter and 3 to 4 feet deep. Its floor receives the open ends of 10 pipes conducting the gas from the condenser or exhauster to the different purifiers, and then to the gas-holders ; the ends of these pipes project upwards to the height of 14 inches, and the vessel e is filled with water to the height of 12 inches, thus leaving the orifice of the pipes 2 inches above the water level. This cylinder has a cover which consists of a smaller cylinder, open below and closed above, fitting into e, so as to form a water lute. Its interior is divided into 5 chambers, as shown in fig. 190, and when the cover is so far lowered into e as to immerse the edges of these chambers into the water, they each connect together a pair of pipes, as shown in fig. 189, at e, which exhibits a hori- zontal section through these chambers. The chambered cover being placed in the position shown in fig. 189, the gas takes the following course : it enters the chamber a! by the pipe a a, passes through the pipe marked 1 into the bottom of the purifier c, and after traversing the layers of purifying material in c, it returns to chamber e of the central valve by the pipe 2 ; thence by pipe 3, it enters the purifier d, and returns to chamber d of the valve by pipe No. 4. From this chamber it can only make its exit by pipe No. 5, which conducts it into B, whence it returns to chamber b by pipe No. 6, and from this chamber it finally passes to the gas-holder through the exit pipe b b. Thus the purifier a is left out of the circuit for the purpose of recharging or revivification ; but when the material in c has be- come exhausted, it can be replaced in the circuit by a, by slightly raising the cover of e, and turning it round so as to bring the chamber a! over pipe 3, and again depressing it to its former position ; by this arrangement d, b and a become the working purifiers, whilst c will be thrown out of the circuit. Thus, by the action of the central valve e, each of the four purifiers can in turn be excluded from the circuit, and recharged or revivified. 191 77«! Governor. — Altliough the gas-holder is, to a certain extent, a regulator of pressure, yet it is difficult, by its action alone, to maintain a pressure so steady and uniform as that required for the supply of gas consumers. It would be difficult, if not impossible, to alter 388 COAL-GAS. the pressure upon the mains frequently during a single night, as is now usually done in towns with a large number of street lamps, without the intervention of an apparatus termed a governor. The governor, which occupies a position between the gas-holder and supply mains, is a miniature gas-holder a, (see fgs. 191, 192, and 193, which represent Mr. 192 Wright's improved governor,) the interior of which, however, is nearly filled by the eon- centric inlet and outlet pipes b and c. Immediately over the mouth of the inlet pipe, and depending from the roof of the inner cylinder, is a parabolic piston d, which hangs within 193 the contracted mouth of the inlet pipe c. The interior cylinder is counterpoised by the lever and weights e e. Now, when the pressure of gas in this small holder increases, — that COAL-GAS. 389 is, when the flow of gas through the inlet pipe exceeds that escaping from the outlet, — the inner cylinder rises ; but in doing so, it carries with it the parabolic piston d, and thus con- tracts the orifice of the inlet, and consequently diminishes the ingress of gas. In this way, by adjusting the weights attached to the lever of the governor, and by always maintaining a pressure in the gas-holder greater than is required in the mains, the gas can be delivered from the governor at any required pressure. In hilly towns, such as Bristol, Bath, Edin- burgh, &c., it is necessary to employ governors at different stages of elevation, in order to produce a tolerably uniform pressure in the different districts. The necessity for this will be obvious, when it is stated, that a difference of level of 30 feet affects the pressure of the gas in the mains to the extent of Vio of an inch of water. Economical and Sanitary Relations of Gas. In a lecture delivered at the Royal Institution in 1853, Dr. Frankland thus estimates the comparative cost of an amount of light from various sources equal to that yielded by 20 sperm candles, each burning 120 grains per hour for 10 hours. s. d. London gases: City, Great Central, Imperial, and Chartered - 4^ Western - - - - 2| Manchester gas - - - 3 The following table exhibits the amount of carbonic acid and heat produced per hour from the above sources of light, the heat generated by tallow being assumed to be 100 for the purposes of comparison. Carbonic Acid. „ „j. Cubic feet. H^^*- Tallow 10-1 - - - 100 s. J. » Wax . - - - - n 2i Spermaceti - - 6 8 Tallow .... - 2 8 Sperm oil (Carcel's lamp) - 1 10 Wax ) Spermaceti f Sperm oil (CarceFs lamp) - . - 6-4 . - .63 London gases : City ~| Great Central ! Imperial j Chartered J Western ... 3-0 - - 22 8-3 - - - 82 5-0 - - - 47 Manchester gas .... 4-0 - . - 32 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 dwelfing-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, ouglit to stimulate tlie 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 390 COAL-GAS. cliarcoal, 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 aio 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 tlie retorts, and thus to add to their durability. The water-gas retorts may be cast from the same pattern as the caunel 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 o.xidc, 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 o, ca.^t on the mouthpiece. In the chambers of tliis 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. Franliland 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 tlie 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. 1st Experiment 2d 3d " 4th " Cubic ft. 930 1,000 Cwt. qr. lb. 2 1 171 2 1 18 2 17 2 7 Cwt. qr. 1 2 1 2 1 2 1 2 lb. 10 12 12 10 lb. 20 20 28 28 lb. 73 77 85 621 Gals. 10-7 7-8 4-5 8-75 Cb. ft. 3,340 3,800 4,157 3,090 1,388 1,576 1,932 1,520 Average production of gas per ton of resin - - - 32,080 cubic feet. Average production of resin oil per ton of resin - - 70'3 gallons. Illuminating power of average gas before purification, as ascertained by shadow test, '75 cubic feet per hour =: light of one short six spermaceti candle. II. Analytical JResidts. Composition of Gas depobb Pukification. Aotual Amount id Cubic Feet. Percentage Amount. 1st Exp. 2d Exp. 3d Exp. 4th Exp. 1st Exp. '2d Exp. 3d Exp. 41h Exp. Avernge. Hydrocarbons - Lisrht carbd. hydrogen Hydrogen Carbonic oxide Carbonic acid - 2.58-7 587-5 13153 967-9 210-G 2C9-0 1. 527-7 1274-8 819-2 409-5 805-7 805-9 197(V2 194-9 254-0 961-0 1297-8 463-5 1137 7-75 17-58 ,S9-38 28-98 6-31 7-OS 40-20 33-54 8-40 10-7S 7-41 21-71 47-90 18-26 4-72 8-22 81-09 42-06 15-04 3-59 7-62 27-64 40-72 17-67 6-85 3840-0 3800-2 4126-0 8090-0 100-00 100-00 100-00 100-00 100-00 Amount of carbon yapor contained in 1 volume of hydrocarbons = 2*8 volumes. 392 COAL-GAS. Composition of Gas after Pueification. 1st Exp. 2d Exp. 8d Exp. 4th Esp. Average. Hydrocarbons .... Light carburetted hydrogen - Hydrogen . - . . - Carbonic oxide . . - - 8-27 18-76 42-03 30-93 7-94 45-06 37-59 9-41 7-78 22-79 50-27 19-16 8-53 32-25 43-62 15-60 8-13 29-71 43-38 18-78 100-00 100-00 100-00 100-00 100-00 Specific gravity of average gas before purification = -65886. " " " after " =: -59133. Value of Htdkocabbons expressed in their equiva- lent Volume of Olefiant Gas. Value of Actual Amount. Value of Percentage Amount in Purified Gas. 1st Experiment . . - 2d Experiment ... 3d Experiment ... 4th Experiment Cubic Feet. 362-2 376-6 428-0 Cubic Feet. 11-58 11-12 10-89 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 Results. Naue of Coal. Cubic feet of Gas per ton. niuminating power per ton in Sperm Candles. Gain per ton by White's process. Gain per cent, by White's process. By o!d procefia. By White's process. By old process. By White's process. Quantity of gas in cubic feet. llluminat- ing power ir. sperm candles. Quantity of Gas. Illumi- nating power. "Wigan Cannel, Ince Hall - "Wigan dn., Balcarre.s - Boghead Canuel Ditto. 2d experiment - Lesmahago Cannel Methill 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 1.3,934 11.088 5,646 5,220 5,060 24,920 38,480 18.560 16,840 4,720 1,632 1,704 9,988 9.308 6.314 5,772 620 47-9 48-5 198-2 290-6 1748 176-2 458 83 9 42-4 67-8 81-8 82-8 lOS-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 q/" 120 grs. per hour. Name of Coal. TVeigut of Coal. B7 old process. By White's process. Wigan Cannel (Ince Hall) Wigan Cannel (Balcarres) Boghead Cannel ..... Lesmahago Cannel Methill Cannel Newcastle Cannel Newcastle Coal (Pelton) .... lbs. • 465-1 539-0 197-5 293-9 421-4 445-7 745-7 lbs. 347-4 378-4 104-8 160-7 202-0 396-7 COAL-GAS. 393 Table Shoviing 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 op Gas. Kate of CoDsumption per hour. Quantity of Gas. Cubic Feet. Cubic Feet. Wigan Cannel (Ince Hall) 5 2263 Ditto by White's process - 6 2500 Wigan Cannel (Balcarres) 5 2512 Ditto by White's process - 5 2618 Boghead Cannel 3 1168 Ditto by White's process - 3 1786 Ditto ditto, 2d experiment 5 2500 Lesmahago Cannel .... 4 1394 Ditto by White's process - 4 2094 Methill Cannel 6 1798 Ditto by White's process - 6 2381 Newcastle Cannel (Ramsay) - - - 5 2049 Ditto by White's process - 5 2660 Newcastle Coal (Pelton) 5 33^6 Resin Gas by White's process j calculated \ from analysis ' 3012 Manchester Gas (June, 1851) ditto ditto 3448 m rCity Company's Gas (July 15, 1851) - 5 3846 m Great Central Company's Gas, do. 5 3546 a " Chartered Company's Gas do. ( calculated \ from analysis ' 3320 •a Imperial Company's Gas - do. ditto ditto 4099 o Western Company's Gas - do. ditto ditto 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. Ciegg'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, 1(),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, 36,0()0 cubic feet of 20 candle gas, or 58,000 cubic feet of 12 candle gas per ton, can be obtained ; whilst Boghead Cannel yields 52,000 cubic feet of 20 candle gas, or 75,000 cubic feet of 12 candle gas. The following table presents in a condensed form Mr. Ciegg's results as to comparative cost : — Name of Coal. Cost of 1000 feet of 20 candle gas by old process. Cost of 1000 feet of 20 candle pas by hy- drocarbon process. Cost of lOno feet of 12 candle pas by hy- drocarbon process. Wigan Cannel at 14s. per s. d. s. d. s. (/. ton - - . . Lesmahago Cannel at IBs. 1 Of 1 3.J Hi per ton ... Boghead Cannel at 20s. per 2 5i llf 9J ton . - - - 2 4i 11 9J 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 Tliermolanip 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 footin". 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 ; defiant 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 7 100-0 If, however, the gases and vapors produced by the above experiment be heated to a con- siderably higher temperature than that at which the wood 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 wood 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 U hours the distillation is com- plete, the" result being, after absorption of carbonic acid, C50 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. Ko. 2. Olefiant Gas. Hydrocarbons . - - - G-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 — ... -42 99-35 100-00 The specific gravity of the purified wood-gas is about -700, and this, coupled with the lirge percentage of carbonic oxide which it contains, renders it necessary to employ burn- COCHINEAL. 395 er3 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 bo employed witli great advantage in Ire- land. Its rapid adoption in many German and Swiss towns proves the practicabihty 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 irt'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 ditferent 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 represents 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 not Ijcen changed, and is equal to 1(»0, 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 rcl ition 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 lie represented by the same relation, since the quality of the samples tried is in proportion to their coloring power." — {Napier.) * Care must bo taken not to aild to the water, which serves to extract the eoloriiis iiintter fniin the (lifforcnt cochineals, more than the requisite quantity of acid sulpliatc of alumina and .sohition of potash, because a stronfrer dose wouhl precipitate a part of the colorin;; matter in tlie state of lake. t For dilutins the liquors the same water must alwaj'S bo used which has served to extract the color- ins matter of the cochineals umler examination, otherwise the darkest decoction would pass into violet, as w.iter was added to it, to bring back the tint to the degree of intensity as that of the decoction to which it is comi)arcd. 396 COOK-METAL. 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. Tlie 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 sui-prising 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 caimot 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,) C"^H^''0'-f- 2H0 ; or, according to Richardson, C'"IP"0' + Aq, and of a liquid fat or olcine. 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 Gadidm family ; especially from the torsk, Brosmitis brosmc. 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 lias 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 w^rks 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 fiits 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 ill 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 surfiice. 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 downwards, 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- buro-h, 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 balk 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. ; Ab'jexchwcfelte, Germ.) It is necessary to distinguish between what is called gas-coke and oven-coke. The word coke applies, properly, to the latter aloae ; 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 Wasiii.xg MACfiiNES. 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 furanccs, 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 wiiic'h it is expo.sed. Hence, good coke cannot be made in a short time, and that used in locomotive engines is com- 'monly from 48 to 06, or even 120 hours in tlie process of manufacture. The prospects of imjirovement in coke-making point rather to alterations in the oven than in the process. Formerly it was not thouglit possil)le 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 Wfest- 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. 195 liiii iinliiiiiiiiiliiiiiiiiiilll I! iMMiinnMi 196 " 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 g h. 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 difiVr- 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 arc 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 fg. 197, and the coal is ignited through the flues e ; the air then enters the flues e and pa'ss'es through the coal, and then ascends the chimneys n, as shown by the arrows. When the current of air has proceeded in this direction f^or some hours, the flues e and chimneys n are closed, and r 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 k and f are closed, and the chimneys g and ii 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 troni 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 tlie 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 tlie 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 witli 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 m Jig. 197 ; in the latter ease 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 eff'ected 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 process 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 influence 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 Wiiste, unless a further supply of air is allowed to have access to it. At this stage of the process, the coke assmnes 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 l)ecomcs 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 ovei«. 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, (CW ;) 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 effect produced by the water, and would point the way to further improvements." " Charred Coal" 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 manufacture : — 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 Mancfactcre. A process has for some time been gaining ground in France known as the " Si/steme 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, " Carborusafion de la Houille Sys- teme Appolt, dicrit jmr les Aufeurs, MAT. Appolt Freres:" 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 ciuchonine 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, which 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 mattkr. 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, difler 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 will 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, such as those of the leaves and tlowers of plants and the blood of ani- mals, are produced by coloring matters with which we are but very httle acquainted, the coloring matters used in the arts, and which have bpen 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 gensris. 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 pet.ds of some flowers. If, for instance, the petals of the orange-colored variety of the Tropmolum majus be treated with lioiling 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 uncombined, red, but its compounds with alka- 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 combination 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 in 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 crj'stallizing. 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 Safllower, disappear rapidly when exposed to its influence. Colors produced by a mixture of two coloring matters arc often found to resist * Another green coloring matter, derived from different epecies of lihamnns, has lately been do- scribed under the name of " Chinese Oreen." It is stated to be a peculiar substance, not, as miglit be supposed, a mixture of a bh:o and a yellow coloring matter. YoL. III.— 26 402 COLOKING 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 proliably due to physical causes. Sometimes this effect is, without doul)t., 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 arc 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-bhie, 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 ijy 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 dcteiniines 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 oxvgen 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, and 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 oljserve, 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 ivdir/o 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 rapidly attracts oxygen, and is reconverted into iudigo-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 bleaching 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, thouglj the matter is one possessing more of a theoretical than a practical interest. It is a well-known fixct, 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 arc soluble in water, are, generally speaking, of the greatest importance in the arts, since they admit of more ready application when they 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 mo.-^t 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 sul>stances 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 sulphuric 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 40J: COLORING MATTERS, the addition of water, when they are insoluble, or not easily soluble in the latter. Others, a,i;:iin, like indigo-blue, dissolve in concentrated or fuming sulphuric acid, without being de- couiposed, and at the same time enter into combination with the acid, forming true double acids, which are easily soluble ia 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 tlie 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 wliich 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 neutnxlizing 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 afiBnity 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, with 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 formula^ all equally probaljle, may not be given, if the compounds with bases be employed for their determination. The compounds of coloring matters with bases hardly ever crystallize. Those with alkalies are mostly soluble in water and amor- phous ; those with the alkaline earths, lime and baryta, are sometimes soluble, sometimes insoluble ; those with the earths and metallic oxides are almost always insoluble in water. The compounds with alkalies are obtained by dissolving the coloring matter in water, to wliich a little alkali is added, and evaporating to dryness — an operation which must be care- fully conducted if the coloring matter is one easily aftected In- oxygen. The insoluble com- pounds, with earths and metallic oxides, are obtiuned cither l)y 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 which occupy an intermediate position between 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 whole 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 lie dyed. When used for this purpose, they are called 7»or(la?its. 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 with 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 arc 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 wiiich takes place under these circumstances is probably not due to any chemi- cal affinity, 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 diflerent from that of other bases. Coloring matters, however, vary nmcli 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 suh^itanlive coloring matters, to the second that of adjeclive 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 indigoferaj 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 indigof/oie 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 in.'>(olable 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 tliis and other coloring matters, and it was soon followed by others. Heeren and Kane oljtained 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, Iccanorine, 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 cr3-stallized colorless substance, fuema'oxi/lhie, which is the origiiinl 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 discover(>d by Robiquet, that if madder be treated for some time with sulphuric acid, and the acid be afterwards completely removed, tlie 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- in" such as lime, sugar, woody tibre, &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, rubiaiiine, two amorphous red coloring matters resembling resins, rnhi- retine and vemntine, and lastly, grape sugar. \Yhcn suVyected to fermentation, the same products are formed, with the exception of rubianinc, 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 docs 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 tijictoria, or common woad plant, Schunck, in like manner, extracted an amorphous substance, easily soluble in water, called by him iiuUt-av, and which, by the action of strong acids, is decomposed into imligo-bluc, 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 sliow a remarkable degree of stability for organic compounds. More extended research will probably .show that many other coloring mattus 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 dnd 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 l)rice. 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, Ijurning 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 spenn ; the quantity of oil being used in the same proportion ;" and he concludes by stating his " confidence in the results." The advantages tlicn 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. 9J. per gal- lon seed oil, against 6.v. Ad. imperial gallon of sperm. Those interested should consult returns, ordered by the House of Commons, — " Ligiit- norsKS, on the motion of Mr. Hume, ' On the Substilution of Rape iSeed Oil for Sperm Oil, and the Saving accruing therefrom: I7th Feb., 1857; No. 15; I8th Jilarch, 1857, 196 and 196 I." In the Supplementary Returns laid before the House of Commons by the Conwiisswner.'i of the Northern Ziy/z^s," 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 mouths 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 culza oil possesses the advantage of remaining fluid at temperatures which thicken the spermaceti oil. " 2. The culza 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 chimnej^s with the culzi 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 : — '■^ Admiralti/, 9t/i 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 arc 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 arc 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- wood 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 tlie 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 disiilaycd in solder- ing the back of a large comb to that piece which is formed into teeth. Tiic two jiarts 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 ; tlie interval between 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. Tlius arranged it is placed in boiling water. The joints, when properly made, cannot be detected, either bv 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 exami)le, 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 sliell, cparated by washing. The rich ore is either Ijroken 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, COPPEPw. 409 each about 16 inches square and li 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 yeais 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 GRiNniNG and Crushimg 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 ' -20 inch, '12 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 separat(,i\ 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 are carried off into a series of slime-pits, where they are allowed to settle. The ivork 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 ivas/e, 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 dii-ectly 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 lA- per cent, of coppei*, is so con- centrated as to afford a metallic yield of 10 per cent., whilst, by means of sizing-eieves, 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 12.s. 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 slime-pit, which answers tliis 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 valuable 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. The water enters it at one of the ends by a narrow channel, aud leaves it at the other. A strong central current is thus produced through the pit, which not only carries with it a portion of valualile slime, but also produces eddies and creates currents towards 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 necessai-y, 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 cither 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'x Process for Smcltincf (Joppcr 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 proer-ss 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 tlie 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 slao- that is, a scoria containing much protosilicate of iron, which is used as a flux in the firsl fusion of the calcined ore, so that any small trace of copper which the slag may con- tain is thus recovered. Tlie 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 4 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 ichitc 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 carbonaceoug 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 Hitelva, Spain, by ivhat is termed ^''Artificial Cementation.'''' (Translated from the newspaper " Minero Espatiol " for January 23, 1S58.) 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 " dissolvcrs." In each of these trouo-hs, or cisterns, are placed about twelve tons of calcined ore, and the trough is then filled'^with water ; which 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 dissolvcr 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 alwavs 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 {pilolics) 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 process 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, when it is found to produce from 65 to 70 per cent, of pure copper. From the remains of the first washings of the 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 l^Notc by the Translator. — The average produce of the copper ores of the Riotinto dis- trict, by this process is under 14- per cent. The following quantities, put into English meas- ure, are taken from the returns of the Government mines at Riotinto, published in the " Revista Miuera :" — Tear. 1 Quantity of Ores raised. '^''"iio^ducei"''''" Produce per Cent. 1854 1855 1856 Average - Tons. 38,915 37,123 37,866 Tons. 720-9 834-5 740-5 1-85 2-24 1-98 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.] Tlie Process of Exlrncting Copper from the Water that Drains out of the Mine at Hlo- tinto, called the '■'' Si/stem of Natural Cementation^'' (Precipitation.) (Translated frona the " Minero Espafiol" for January 28^ 1S58.) 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 yards 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 drain-age from other points of the mine, is directed through a channel to the adit " San Roquo," 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 RoquCj" 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 6y the Translator. — The " Revista Mmera," (a mining review,) published by the engineers of the Government School of Mines, in Madrid, gives returns of tlie Government mines at Riotinto for the year 1856 ; wherein it is stated tliat the ((uantity of copper taken out of this mineral water, by " natural cementation," amounted, for the year, to 206^ tons. — S. H.] ♦ But this averasc of 2 per cent for tlio 4 ycar.s contains and inchulcs tlic copper produced from tlio wat('r whicli drains out of tlie mine, and wliicli copper, for tlie year 1S5('>, amounted to '2()(')j tons; de- ductinf? tliis quantity from the return, 740^ tons, for that year, and the produce would bo only 1-43 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 Copper Frocexs. — " At Linz on the Rhine, and some other localities in Germany, the poorer sulphides of copper, containing from 2 to 5 per cent, of that metal, are treated by the following process : — " The ores coming directly from the mine, and without 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 tlie diaphragm, or false bottom, is connected, by means of proper fluos, with a scries of oblong retorts, through each of which a current of air is made to pass from a ventilator, or a j^air 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 which succeed it. " The retorts — which are formed of fire tiles, and about G 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 sulphurous 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 laid 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 are 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 are drawn off into convenient troughs, and the cop- per i)recipitated 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 subsecpient operation. " It has l>cen found that, by operating in this v,ay, 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, C cwt. of coal are said to l)e required to roast one ton of ore, whil.-t the same quantity of blende is roasted by an expenditure of 4 cwts. of fuel." Treatment of Copper Ores hi/ Jlydroehloric Acid. — " At a short distance from the vil- lage of Twista, in the Waldcck, several considerable bands of sandstone, more or less im- pregiuated 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 natiu-e of the granular quartzitic gangue with which the copper is asso- ciated, suggested, some two years since, to Mr. llhodius, of the Linz Jlctallurgic Works, the possibility of treating these ores by means of hydrochloric acid, and a large estabtishment 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, 10 dissolving tubs, and a considerable nuniljir 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 furnished with a large wooden revolving agitator, set in motion by a run of overhead shaftir.g in con- nection with a powerful water-wlicel. 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. * Kooorils of Mining and Metallurgy, p. 1S2. 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, 2s. 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 1^ ton of scrap iron at £4 5.?. 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 may 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 siiould contain but little lime or any other substance than the ores of copper soluble in dilute liydruchloric acid. It is also essential that the mine should be in the vicinity of alkah works, in order that a supply of acid may be obtained at a cheap rate, and also that scrap iron be procurable in suflBcient quantities and at a moderate price." Assay of Copper Ores. The ores of this metal are exceeding numerous, but may be comprehended under three classes : — The /?r.s< 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 16 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 arc now placed in the furnace, previously heated to red- ness, and the pot is allowed to remain uncovered until th(^re 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 co^er, 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 rapid pouring into a mould, or by allowing the pot to cool, and then break- ing it. The metallic '■'■ j^rill " 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 Regiilus. — 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 scoriaj 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 tlie 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, arc operated on, the roasting and subsequent reduction may be made directly qu 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 iU COPPER. tbe 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 regulus must 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 1^ 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 cither 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. Orcf: of the Tliird 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 tliis 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 he effected either Ijy the Cor- nish method, or by the humid process, to be hereafter described. Cornish Metliod of condKclinrj an Assai/. — 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 practice 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 vrcighod out and carefully mixed with a flux consisting of nitre, borax, lime, and fluor-spar, and the 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 arc commonly employed in the following propor- tions: — Borax, 5 dwts. : lime, l^ladlefuls; fluorspar, 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 tlie contents of the pot may be poured into a suitable iron mould. The button or regulus i.s now examined, in order to determine whether a suital)le proportion of nitre has been used. If the right quantity has l)een employed, the button, v.hen lirok en, should present a granular fracture, and yield from " 8 to 10 for 20" for copper, i. c, from 40 to 50 per cent. However rank a sample may Ije, it should never be mixed with above 9 or 9^ dwts. of nitre ; and if the amount of sulphur be small, 3 dwts. arc often sufficient. The gray sulphides, the red and black oxides, and carbonates, have sulphur added to them for the purpose of obtaining a regulus. Iliglily sulphuiizcd samples, requiring above 9^ dwts. of nitre, are sometimes treated in a diflcrent way. * Tl)e liiill^! u.sod for tliis purpose is three-quarters of an inch in tliameter nnd half an inch in doptli. 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 rogulus 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 suilicient. 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 kt'pt constantly stirred with 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, tlie temperature must be raised nearly to whiteness during a few minutes, and the as.^ay 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 niti-e, 7+ dwts. of tartar, and 1 V 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, 3} 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 now 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 add 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 s[)iiting. 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 wrought iron, about two inches in length, three-quarters of an inch in width, and a quarter of an inch in thickness, is now introduced, and the liquor gently heated on the sand bath until the whole of tlic copper has been thrown down. The liquor is iiow re- moved by means of a glass siphon, and the metallic copper freed from all adhering chlo- rides, by means of repeated washings with hot water, and then dried in a water bath, and weighed. In case the mineral operated on .should contain tin or antimony, very minute traces only of these metals will be found with tlie precipitated copper. AVhen 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 will be precipitated as sulphate of lead, and be removed by filtration. The results obtained by this process are somewhat higher than afforded bv 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^ Tliis salt is used to jji-oduce a fine green in fireworks. ♦ Copper, Si^lpiiate of, called in commerce Bute Vitriol. Bh'e Stone. Bi.imo 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 which a subsulphidc of copper is * The rpfininf; flux consists of two parts of nitre and one of white tartar fused together, and subse- quently pounded. ~] 41G COPYING. produced ; this is converted into sulphate, by i-oasting 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 17S0, 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 dumping, 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 Underwood and Burt patented a method of taking copies by the action of a chemically prepared paper, in a chemical ink, by which, not only arc 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. Underwood : — "But while the means employed for producing the desired effects may be varied, I pre- fer the following for general use : — I damp the jiapcr, i)archment, or other material which 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 water, and either use it immediately, or dry it and subsequently damp it with water as it is required for use. I then prepare the material which I use for jiroducing the characters or marks, and which may be called copying ink, by simply dissolving (in a water bath) pure extract of logwood in distilled water; or, for printing,! 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 water ; but a larger number of copies may be taken by dusting or throwing over the original, before the ink has thoroughly dried, a powder composed of five parts of powdered extract of logwood, one part of powdered gum arable, 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, niaps, &c., will give one or more dear 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 15th December, by Mr. John Under- wood. COQUILLA NUTS. These nuts are produced in the Brazils l)y the Atfalca funifera. They are suitable for a great variety of small ornamental works, and are manufactured into the knobs of umbrellas and parasols. CORDAGE; — {C'ordaffe, Fv. ; Tamcerk, 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 m inches ; one-fifth of the product will be the number of tons' weight which it will bear: this is, however, uncertain. COROMANDEL WOOD. The wood of the Dyospyros hirsuta. CORROSIVE SUBLIMATE, Mercury, Chloride of, or FrotocJiloride, {Ikntochloritrc dc vrcrcure, Fr. ; Aetsendrs rjuecJ^ilber snblimaf, 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 stoue- ware cucurbit. The sublimate rises in vapor, and encrusts the globular glass capital with a wliite mass of small prismatic needles. Its specific gi'avity 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 MANUTACTUEE. 417 lowed in profusion is the best antidote. A solution of corrosive sublimate has been long employed for preserving soft anatomical preparations. By this means the corpse of Colonel Morland was embalmed, in order to be brought from the seat of war to Paris. Ilis 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 pi-eventing 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 Xavy 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 Goadby'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" YS-SS Chlorine - - 35-5 26-14 135-5 100-00 H. M. K See Mercury. CORRUGATED TROX. 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 '/i* of an inch in thickness ; the weight per foot is 3 lbs. ; the whole weight of the centre roof of 10,235 superficial feet bemg scarcely 13f tons, and the side roofs, of 5,405 square feet, weigh 1\ 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 4() 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 ; D 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. « 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 bolt 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 contain^" 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 MANUFACTURE. 198 ^ 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. 190 The cotton is placed upon the travelling creeper marked «, 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 fluted rollers, which serve it to the beater. The top feeding rollers are weighted bv levers and weights e e, 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 ff. 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 tlie 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 MANUFACTUPvE. 419 nfji'^nL'^lf ^^ the points Of the spikes being at the same distance from the axis as the «n7uo= IT -i ?h^'- .. ' '^^, ^'^^*^', '^''^''^''^^ ^^°"^ ^'^'O turns per minute, the blades and th n« f !r> f '''"°" T^ considerable ibrce as it is passed from the feeding rollers, and tnus tree it irom many of its impurities. hn rJ'^.rt?^^ '''"^"''' ^^''•^^'f '''"";' f"^ ^"^'^'•' ^'•^ P'^^'^^ a "»°^ber of wedge-shaped IpH;S f r''/ ^e"]'-"'-^"'^'- 8"^, through the narrow openings of which the°dirt and seeds fall to the floor, their removal being effected through the doors in the framintr 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 framinc^ orms 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 machine ' '* '' ""'"'^ "'''^ °'''^' ''^'^^ ^""^ '^'^ operations of the lap tho=f f ■ "^/' ^^^' represent skeletons of the old cards, to facihtate the comprehension of hese complex macnnes. F,rf. 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 "^r^ b, and then falling in narrow fillets into its can. Fiff. 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 : d, L c, the card- end passing between compressing rollers into the can a. 203 420 COTTOJq^ MANUFACTURE. per week of 60 hours! ™'^'' ^'^'^'"'' "^'^ ^^''^ ^^^^d f«r COO lbs. of twenties upoiU^TeS clplt'entnT "" '°°^' ''^"^'^^'^'■' ^"*'-^^' ^^ --' -^^ -ay be looked 204 duced 'i'lZn/'r' '°^""ff *^t»r^d »,y Messrs. Hetherington & Sons, Manchester, having pro- hivention nTi ♦'' ''f''^'" '.*'" in the preparation of fine yarns, we give a brief history of its invention prior to describmg it in detail. About the year 1844, Mr. Jean Jacques Bourcart, one of the partners of the eminent COTTON MANUFACTURE. 421 firm of Messrs. Nicolas Schlumberger & Co., of Guebwiller, in the department du Haut Rliin in the kingdom of France, offered a prize of a considerable sum of money to any per- son who should invent a machine that would supersede the carding engine in the treatment of the fibres of cotton, suitable for fine numbers, such machine to be free from the objec- tions urged against the carding engine of breaking the fibres of the cotton, and delivering them in the staple or hook form ; and besides this, it was to possess the peculiar property of separating the long fibres from the short ones ; and after laying the long fibres parallel to each other, pass them out of the machine in a perfectly cleaned state in the form of a sliver ready for the drawing frame. In a short time after this announcement Mr. Bourcart was waited upon by Mr. Josae Heilmanrf, of Mulhausen, in the department du Haut Rhin in the kingdom of France, ma- chine maker, who informed him that he claimed the prize. Mr. Heilmann, feeling satisfied that his invention was a valuable one, made application for a patent in England, which patent was sealed on the 25th of February, 1846. The specification of Mr. Heilmann's invention is very clear and concise, and a single extract from it will be sufficient to convey to the mind of the practical spinner the nature and object of his invention. He says : — " My invention consists, secondly, in a new com- bination of machinery for the purpose of combing cotton, as well as wool and other fibrous materials, into which machine the fibres as they come from the dressing-machine are intro- duced in a lap sliver or fleece, which is broken asunder, and the fibres are combed at each end, and the long and short fibres are separated, the long ones being united in one sliver, the short ones in another, and they are passed out of the machine thus separated ready for drawing, roving, and other subsequent operations." Mr. Heilmann did not live long enough to reap the reward of his genius for inventing this and other important machines, and his son, Jean Jacques Heilmann, was under the necessity of bringing an action for the infringement of the combing machine patent against certain parties in Yorkshire ; the trial took place before the Lord Chief Justice of the Queen's Bench and a special jury at the Guildhall, London, on the 27th and 2Sth of Febru- ary, 1852, which resulted in a verdict for the plaintiff, thereby establishing the validity of the patent. Since that period a considerable number of machines have been set to work in this country ; and although several patents have been taken out for certain improvements introduced into these machines, still the combination of a delivering, combing, and drawing apparatus, and their mode of action, is retained, as will be seen in the following description of Cross Section of Combing Machine, fig. 204. 1 is the lap of cotton resting upon the two wooden rollers 2, 2a. When motion is given to these rollers, they cause the lap to unwind and deliver the sheet of cotton down the inclined conductor 3, and between the fluted steel feeding roller 4, and the leather-cov- ered pressure roller 4a ; to these rollers an intermittent motion is given by means of a star wheel ; they make '/lo of a revolution to one revolution of the cylinder 6, this motion being effected during the time the cushion plate oa is forward, and the nipping plate 5 is lifted from it. The cushion plate 5rt is hung upon the centre 56, and the nipping plate upon the shaft 5c, and this shaft receives motion from a cam at the end of the machine through the lever 5«, the connecting rod 13'/, lever 13'-, and shaft 136, — the parts being so arranged that the cushion plate 5a is pressed backward by the nipping plate 5, but as soon as the pressure is removed it is drawn forward by a spring until it ai-rives at the strap. Besides this move- ment, the nipping plate is caused to move on its own axis, which enables it to quit contact with the cushion, while the cotton is being fed in between them. In the engraving {fig. 204) the cushion 5a is represented as thrown back by the nipping plate 5, and while in this position the cotton is held between them, until tlie combs on the cylinder pass between the fibres of cotton which protrude, and remove from them all im- purities and the fibres which are too short to bo held by the nipper. The combing cylinder Ca is attached to the shaft, or axis 6, by which it is caused to revolve. The periphery of this cylinder is divided into four unequal parts by the combs 66 on one side, and the fluted segment 6c on the other side ; the spaces between them being plain to allow time for the nipper and leather detaching roller 8a to change their positions. The combs on the cylinder are made with teeth at various distances, the coai-ser ones taking the lead, and finer teeth following, the last combs having more than 80 teeth in a lineal inch. All impurity or waste mixed with the fibres held by the nipper is carried away by these combs, which at every revolution are cleaned by the cylindrical brush lOa, strip- ping the waste from them, and depositing it upon the travelling creeper 11a, formed of wired cloth, wliich carries it down until the doffing knife, or steel blade 12, removes it in the usual manner ; it then drops into a waste box, and is afterwards worked into coarser yarns. A cylindi'r covered with wired cloth "is sometimes used instead of the travelling creeper, and acts in a similar way. As soon as the combs have all passed the fibres held by the nipper, the cushion plate 5a is drawn forward, and the nipper plate 5 is lifted from it, and thus releases the fleece ; the fluted segment Oc on the cylinder is at the same time passing immediately under the cushion 422 COTTON MANUFACTURE. plate 5a, the ends of the combed fibres lying upon it, and as the leather detaching roller 8a has been lowered into contact with the fluted segment, they are then drawn forward ; but as it is necessary to prevent any fibres passing that have not been properly cleaned or combed, the top comb 7 is placed between the nipper and the roller, and as this comb falls and penetrates the fleece just in front of the part uncombed by the cylindrical combs, it prevents any waste from being drawn forward with the tail end of the clean fibres. The leather detaching roller 8a, in addition to its occasional contact with the fluted seg- ment 6f, is always in contact with the fluted steel detaching roller 8, and participates in its movements. These rollers are stationary while the cylinder combs are cleaning the fibres projecting from the nipper, but as soon as that operation is completed, they are put into motion, and make part of a revolution backward, taking back with them the fibres previously combed, but taken out of the way to allow the cylinder combs to pass, in order for the next fibres coming forward to be joined or pieced to them, so as to form a continuous sliver or ribbon. As soon as the backward movement is completed, the leather detaching roller 8a is made to approach the cylinder by the lever S/, which receives motion from a cam at the end of the machine, through the lever Sd, connecting rod 8c, lever 14c, and shaft lib. Before, how- ever, it comes in contact with the fluted segment 6c, the movement of the fluted roller is reversed, and it is caused to turn forward, producing a corresponding movement of the de- taching roller So., the speed being so arranged that, before they are allowed to touch each other, the peripheries of the fluted segment Gc and the roller 8a travel with an equal veloc- ity. At this stage, the ends of the fibres cleaned by the cylinder combs and projecting from the nipper, are resting upon the fluted segment ; and the roller 8a, in coming in contact with it, presses upon those fibres, and immediately draws them forward ; the front ends are then lifted by the leather roller and placed on the top of those fibres previously cleaned, and brought back to receive them. The pressure of the rollers 8 and Sa completes the piecing of the fibres ; the motion of the rollers being continued until the tail end of the fibres is drawn through the top comb, and a length of fibres is delivered to the calender rollers, — sufficient slack being left between to allow for the next backward movement. The roller 8a is then raised from the fluted segment and ceases to revolve. From the calender rollers, the combed cotton passes along the front plate or conductor, where it joins the slivers from the other five heads of the machine, and with them passes through the drawing head, and is then deposited in a can ready to be removed to the draw- ing frame. The movements above described being necessary for each beat of the combing machine, they must all recur each second of time, or sixty times each minute. Recapitulation. — The combing machine is fed or supplied from 6 laps of cotton, (each lap being formed from about 18 slivers from the breaker carding engines, and doubled into a lap in the lap machine.) Each lap is 8 inches wide and about 12 inches diameter when full. The following description of the manner in which the combing machine works is con- fined to one head supiDlied by 1 lap, as each of the 6 heads shown in Jig. 204 is exactly like the others : The lap of cotton having been placed on a pair of revolving lap rollers, the fleece, or sheet of cotton, is conducted down an inclined guide to a fluted steel feeding roller, which places the cotton between the open jaws of an iron nipper. The nipper is then closed and made to approach the comb cylinder, by means of a cam, where it holds the fibres in such a position that the combs of the revolving cylinder pass between and remove from the fibres all impurities and short or broken cotton, which are afterwards worked up into yarns of a coarser quality. As soon as the combs have all passed through the cotton, the nipper recedes from the cylinder, and as soon as it has reached the proper distance, opens its jaws, and allows the partially combed filires to be drawn out of the fleece, by means of a leather-covered roller, which works for this purpose in contact with the fluted segment on the comb cylinder, and with the fluted steel detaching roller. The drawing out of these fibres causes the ends of those fibres which were before held in the nipper to pass between the teeth of a fine top comb, thus completing the combing of each separate fibre. Previous to the movement for drawing out the fibres from the uncombed fleece, the detaching roller has made a partial revolution backwards, and taken with it the combed cotton previously delivered, in order to piece it to the fil)res just combed. The machine is so arranged that the forward movement of the detaching roller overlaps the ends, and brings out the cotton in a continuous sliver to the front of the machine, where it joins the other five slivers which have been simultaneously produced on the other heads of the machine. The united slivers then pass through the drawing head to the next opera- tion — the drawing frame. (See Vol. 1.) Fig. 204a is a drawing frame, by Hetherington & Sons, containing all the latest im- provements, i. e., greater strength of materials ; a stop motion to stop the frame, when COTTON MANUFACTUEE. 423 a sliver breaks ; a roller plate to prevent roller laps. The coiler motion, by ineuu: the sliver is placed in the can in circles overlapping each other on the principle ; of which described 204 a in fifj. 2046, the can roving frame ; 4 rows of draught rollers instead of 3 ; and lastly, an apparatus for lifting all the roller weights from off the rollers at any time when the frame may be stopped. The stul)bing frame {ficj. 2046) is the first machine which puts twist into the silver, and prepares it for the roving frame, which in its principle it precisely resembles. 2046 The preliminary spinning process is called rovinrt. At first the torsion is slight in pro- portion to the extension, since the solidity of the still coarse sliver needs that cohesive aid only in a small degree, and looseness of texture must be maintained to facilitate to the utmost the further elongation. Fig. 205 shows the latest construction of a bobbin and fly frame, as made by Messrs. Higgins & Sons, of Manchester. As the principle of action is similar to that already de- scribed, it only needs to add that many improvements have been introduced by the makers, as will be seen on reference to the engraving. 1 represents a front view of the frame; 2 a view of the back of the frame ; 3 shows the driving pulley and gearing end ; and 4 the same end with the iron casing removed, so as to exhibit the works inside. The spindles and bobbins being now driven by gearing instead of by bands as formerly, - and greater strength of materials being introduced throughout tiie frame, it is capable of producing a better quality with an increased quantity of rovings than was possible formerly. Fic). 20G also represents a similar frame for rovings, made by Iletherington & Sons. Its action is the same as that already described. Fig. 207 is a view of one of the most improved forms of the throstle frame by Messrs. Iletherington & Sons, Manchester. 424 COTTON MANUFACTURE. 205 COTTON MANUFACTUEE. 206 425 The Self- Ac tin rf Midc. — In a previous edition of this work, mention was made of the patent self-acting mules of Mr. Roberts, of Manchester, and of Mr. Smith, of Deanstone. Since the period when that notice was written a great number of patents have been olj- tained for improvements on the original patents, by Mr. Potter, of Manchester, Messrs. Big- gins & Whitworth, of Salford, Mr. Montgomery, of Johnstone, Messrs. Craig & Sharp, of Glasgow, and many others. ^ Mr. Roberts's self-acting mule, which was practically the first introduced, has maintained its ground against all competitors, and is still the mule which is most extensively used and approved in the cotton trade. As might be expected, it has undergone a variety of improvements and alterations by the various machine workers who have made it since the expiration of the patent, but Iiy none more than by Messrs. Parr, Curtis & Madely, of Manchester, who have devoted a large amount of time and expense in its perfection. They are the proprietors of six patents for this mule, the invention of Mr. Curtis, of the manager Mr. Lakin, and of Messrs. Rhodes & Wain, the combination of which has enabled that firm to produce a very superior self-acting mule, and given them a decided lead as makers. The following are some of the principal improvements they have effected: viz., substi- tuting a catch-box with an eccentric box, in lieu of a cam shaft, to produce the required changes ; an improved arrangement of the faller motion, which causes the fallcrs to act more easily upon the yarn, and not producing a recoil in them when the " backing-off " takes place, thus preventing " snarls " and injury to the yarn ; in applying a spiral spring for the purpose of bringing the backing-off cones into contact, by which the operation of " backing-off" can be performed with the greatest precision. The backing-off movement is also made to stop itself, and to cauS'e the change to be made which affects the putting-up of the carriage, which it does in less time than if an independent motion was employed. They have also an arrangement for driving the back, or drawing-out shaft, by gearing, in such a manner that, in the event of an obstruction coming in the way of the carriage going out, the motion ceases and prevents the mule being injured. By means of a friction motion, the obj'cct of which is to take the carriage in to the roll- ers, the carriage will at once stop in the event of any obstruction presenting itself. For the want of an arrangement of this nature, lives have been lost and limbs injured, when care- less boys have been cleaning the carriage whilst in motion, and have been caught between it and the roller beam, and thus killed or injured. Another improvement consists in connecting the drawing-out shaft and the quadrant pinion shaft by gearing, instead of by bands, thercljy producing a more ]ierfcct winding-on, as the quadrant is moved the same distance at each stretch of the carriage. They have also made a different arrangement of the headstock — or self-acting portion of the mule — caus- ing its height to be much reduced, which makes it more steady, oIKm-s less obstruction to t'.ie light, enables the spiimer to see all the spindles from any part of the mule, and allows a -larger driving strap, or l)elt, to be used, which in low rooms is of considerable importance. Tlie result of these various improvements is the production of one of the most perfoct spin- ning machines now in the trade. For spinning very coarse numbers, say G\s, they have patented an arrangement, by which the rotation of the spindles can be stopped, and the operation of baekiug-off performed, during the going out of the carriage, thus effecting a considerable saving of time. 426 COTTON MANUFACTUEE. Some of their mules are working in the mills of Messrs. Thomas Mason & Son, Ashton- under-Lvne, and are making five to five-and-a-half draws per minute, the length of the stretch being 67 inches — a speed and length of stretch never previously attained. The following is a description of one of those excellent mules : — Fig. 208 is a plan view, f(j. 209 a transverse section, and fg. 210 an end view of so much of a mule as is requisite for its illustration here. 208 As there are many parts which are common to all mules, most of which have been pre- viously dcsci-ibed in the notice of the hand mule, we shall therefore only notice the more prominent portions of the self-acting part of the mule. Among such parts arc : the framing of the headstock a ; the carriage n ; the rovings c ; the supports d of the roller beam e ; the fluted rollers a ; the top rollers a' ; the spindles b ; the carriage wheels 6' ; the slips, or rails, 6', on which tEey move ; the faller wire 6' ; the counter-faller wire b*. The following COTTON MANUFACTURE. 427 are the parts chiefly connected with the self-acting portion of the mule : — The fast pulley f, the loose pulley f', the bevels f* and f', which give motion to the fluted rollers ; the back, or drawing-out shaft g, wheels g' and g", by which, -through the shaft g^ and wheels G'* and G^, motion is communicated to the pinion g° on the shaft g", and thence to the quadrant g'. The scroll shaft h, the scrolls h" and a'-, the catch-box n'', for giving motion through the bevel wheels ii^ and u* to the scroll shaft. Drawing-in cord II^ Screw in radial arm i, nut on same i", winding-on chain r, winding-oa band i^, drawing-out cord i\ Pinion i^ on front roller shaft, to give motion through the wheels i^, i', and i", to drawing-out shaft g. Pinion j, and wheels j*, J^, and J^ for giving motion to shaft j* ; pinion J^ giving motion to backing- off wheel A On the change shaft k is keyed a pinion which gears with the wheel j', and 209 receives motion therefrom. One-half of the catch-box k' is fast to one end of a long hol- low shaft on which are two cams, one of which is used to put the front drawing roller catch- box M into and out of contact ; the other is used for the purpose of traversing the driving strap on or off the fast pulley p as required. The other half of the catch-box k' is placed on the shaft k, a key fast on which passes through the boss of the catch-box, and causes it to be carried round by the shaft as it rotates. Though carried round with the shaft, it is at liberty to move lengthwise, so as to allow it to be put into and out of contact with the other half when required. The spiral spring k'' is also placed on the shaft k, and continually 210 bears against the end of the catch-liox next to it, and endeavors to put it in contact with the other, which it does when permitted and the changes arc required. Tlie cliangc lever k'-' moves on a stud which passes through its boss a" ; near which end of this lever are tlie adjustable pieces a'. When the machine is put in motion, sujjposing the carriage to be coming out, the driving strap is for the most part on the fast pulley f when motion is gi^-en tlirough the bevel wheels f'- and y' to the drawing rollers a, which will then draw the rov- ings c off the bobbins, and deliver the slivers so drawn at the front of the rollers; and the same being fast to the spindles, as the carriage is drawn out the slivers are taken out also, and as the spindles at this time are turned round at a ([iiick rate, (say (^(HM) revolutions per minute,) they give twist to the slivers and convert them into yarn or twisted threads. Mo- tion is communicated to the spindles from the rim pulley y\ through the rim band f', which 428 COTTON MANHFACTUEE. passes from the rim pulley to a grooved pulley on the tin roller shaft, round which it passes, and thence round the grooved pulley f'^ back to the rim pulley, thus forming an endless band. It will be seen that the rim band pulley and the other pulleys, over or round which the rim band passes, are formed with double grooves, and the band being passed round each, it forms a double band, which is found of great advantage, as it will work with a slacker band than if only one groove was used ; there is consequently less strain on the band, and it is longer. A string or cord passes round the tin roller to a wharve on each spindle, round which it passes, and thence back to the tin roller, and thus, when the tin roller receives motion from the rim band, it gives motion to the spindles. The carriage is caused to move outwards by means of the cord l, one end of which is attached to a ratchet pulley fixed on the carriage cross, or square l\ and is then passed over the spiral grooved pulley L" fast on the drawing-out shaft g, and passes thence under the guide pulley l^ round the pulley l* to another ratchet pulley, also on the carriage square, where the other end is then fastened. The cord receives motion from the pulley l", round which it passes and communicates the motion it receives to the carriage, the carriage wheels 6' moving freely on the slips I?. When the carriage has completed its outward run, the bowl a" on the counter faller shaft comes against the piece «', depresses it and the end of the lever k^ to which it is at- tached, and raises the other end, and with it the slide e, on which are two inclines. A round pin (not seen) passes through the boss of the catch-box next to the slide, and bears against the sliding half of the catch-box, and holds it out of contact. When the slide c is raised, the part of the incline which bore against the pin and kept the catch-box from being in contact, is witlidrawn, on which the spring puts them in con- tact, and motion is given to the hollow shaft, and the cams thereon ; one of which causes the catch-box m to be taken out of contact when motion ceases to be given to the drawing rollers and to the going out of the carriage ; and the other causes the driving strap to be traversed off from the fast pulley on to the loose one when motion ceases to be given to the rim pulley, and thence to the spindles. The inclines on the slide arc so formed that, by the time the shaft has made half a revolution, they act on the pin and cause it to put the catch-box out of contact. The next operation is the backing-off or uncoiling the threads coiled on the spindle above the cop, which is effected by causing the backing-off cones attached to the wheel J*^ to be put into contact with one formed in the interior of the fast pulley F, when a reverse motion will be given to the rim pulley and thence to the tin roller and the spindles. The backing-off cones arc put into contact by means of a spiral spring, which, when the strap fork is moved to traverse the strap on to the loose pulley, it is allowed to do. Simul- taneously with the backing-off, the putting down of the faller wire takes place, which is effected through the reverse motion of the tin roller shaft, which causes the catch c' to take into a tooth of the ratchet wheel c", when they will move together, and with them the plate c^, to a stud in which one end of the chain c* is fastened, the other end of which is attached to the outer end of the finger c*, fast on the faller shaft. When this chain is drawn for- war.l by the plate, it draws down the end of the finger c* to which it is attached, and there- by partially turns the faller shaft and depresses the faller wire i^, and, at the same time, raises the lever t", the lower part of wliich bears againt-t a bowl attached to a lever which rests on the builder rail <•". As soon as the lever c^ is raised sufficiently high to allow the lower end to pass over, instead of bearing against the bowl, it is drawn forward by a spiral spring, which causes the backing-off cones to be taken out of contact, when the backing-off ceases, and the operations of running the carriage in and winding the yarn on to the spin- dles must take place. When the cones are taken out of contact, the lower end of the lever N is withdrawn from being over the top of the lever n\ leaving that lever at liberty to turn, and the catch-box n* thereupon drops into gear, and motion is communicated to the scrolls ii' and ir, and to tlio cords n^ and n"". The cord n^ is at one end attached to the scroll n', and passes thence round the pulley n^ to the ratcliet pulley ii' fixed to the back of the carriage square. The cord ii' is at one end attached to the scroll ii^, and passes thence round the pulley h"* to the ratchet pulley n" fixed to the front of the carriage square. It will thus be seen that the carriage is held in one direction by one band, and in another by the other band, and that it can only be moved in either direction by the one scroll giving off as much cord as the other winds on. When the catch-box ii" drops in gear, the scroll n' winds the cord n^ on, and draws the carriage in. It will thus be seen tlint the carriage is drawn out by means of the back or drawing-out shaft o, and is drawn in by the scroll h\ The winding on of the thread in the form of a cop is effected by means of Mr. Roberts's ingenious application of the quadrant or radial arm g', screw i, and wind- ing-on chain i^ and band i^ The chain i'^ is at one end attached to the nut i' and at the other to the band i^ During the coming out of the carriage, the drawing-out shaft, through the means of the wheels G*, g', g* and g**, .shafts g' and g", and pinion g**, moves the quad- rant which, by the time the carriage is quite out, will have been moved outwards a little past the perpendicular. The chain is wound on to the barrel by means of the cord o, which, COTTOIT MANUFACTURE. 429 being fixed and lapped round the barrel as the carriage moves outward, causes it to turn. On the barrel is a spur wheel which gears into a spur pinion on the tin roller shaft, (these wheels, being under the frame side, are not seen in the drawing.) The spur pinion is loose on the tin roller shaft, and as the carriage comes out it turns loosely thereon, but as the carriage goes in, the chain i^ turns the barrel round, and with it the spur pinion. A catch on a stud fixed in the side of the pinion, at that time taking into a tooth of the ratchet wheel i fast on the tin roller shaft, the motion of the spur pinion is communicated to the tin roller shaft, and thence to the spindles, causing the thread or yarn spun during the com ing out of the carriage to be wound on the spindles, in the form of the cop, while the car- riage goes in. At the commencement of the formation of a set of cops, when the yarn is being wound on the bare spindles, the spindles require to have a greater number of turns given to them than they do when the cop bottom is formed. To produce this variation, the following means are employed : — At the commencement of each set, the screw in the radial arm is turned so as to turn the nut i' to the bottom of the screw, where it is near to the shaft on which the quadrant moves ; consequently little or no motion is given to the chain, and the carriage, as it goes in, causes the chain to be drawn oft' the band. As the formation of the cop bottom proceeds, the screw is turned and the nut is raised ; by which means a less quantity of chain is drawn off" the barrel ; the chain, at ihe point of attachment, gradually following the carriage as it goes in. During the going in of the carriage the quadrant is drawn down or made to follow the carriage by the chain pulling it, the speed at which it is allowed to descend is regulated by tlie motion of the carriage ; the quadrant, during the going in of the carriage, through the pinion g'', shafts g^ and g'*, and wheels g\ G", g'' and g* driving the drawing-out shaft. When the carriage has completed its inward run, the bowl a* comes in contact with the piece a'^, and depresses it and the end of the lever k^ to which it is attached, and also the slide c, which then allows the catch-box k' to be put in contact, and causes the cam shaft to make another half revolution. During this half revolution of the cam shaft, the cams cause the catch-box m to be put in contact, and the driving strap to be traversed on to the fast pulley, and, by the latter movement, the catch-box h" is taken out of gear and the winding-in motion of the scrolls ceases, and the carriage will again commence its outward run, and with it the spinning of the thread. Fi(/. 211 is a view of a beetling machine, made by Mr. Jackson, of Bolton, for the firm 211 JIL a= 430 COTTON MANUTACTUEE. of Messrs. Bridson, Son & Co., of that town, a is the beetling roller, and b, c are the rolls of cloth which are to receive the peculiar finish, which beetling alone can give to cot- ton cloths. Although this is a very simple machine, yet it is questionable if it or any other modern invention can effectually take the place of the old-fashioned but useful upright wooden beetle. The following extracts from the circular of Messrs. Leariug & Co. present so complete a view of the state of the cotton trade at this date, that they are now and will continue of much interest and import;mce : — " Mobile, September let, 1858. " The close of the commercial year, ending the 31st of August, gives the total receipt of cotton at all the American ports as 3,113,9(32 bales, against 2,039,679 bales of the year previous. Of the past year's receipts, England took 1,809,966 bales, the rest of Europe 7sO,489 bales, while the United States bought 595,562 bales. This shows an increase to Great Britain, a falling off in the exportatious to the Continent and other parts, and a dimin- ished consumption in the United States. " It is important to remark, that this falling off in the exportation to the Continent of Europe, and»also the home consumption, does not necessarily involve any actual diminution in consumption ; because, what the Continent of Europe failed to take direct of the raw material, will be represented by increased re-exports from Liveipool, and increased demands for yarns from the English spinner ; and what the United States failed to buy and work up, has been bought and will be worked up by others. Consequently, although on the surface a falling off in consumption may appear as in regard to the Continent and America, the demand will be supplied through othei^ilmnnels in a proiiortionately increased ratio. " Added to this established consumption, is the natural increase throughout the world in excess of supply. The opening up of China, and the mutiny in India, which, by inter- rupting not only the growth of cotton there, but also the weaving industry of the natives, have increased the demand for yarns and cloths from England, conspire to add to the de- mand for our staple. The last large receipts of Suiats from India occurred during the blockade of the Chinese ports ; consequently the exports from Bombay, usually sent to China, were, by this cause, thrown upon the Liverpool market, induced also by the attrac- tion of high prices. " Tlie universal prevalence of the panic, the long-continued prostration in trade, and the working of short time, have reduced the stocks of goods everywhere ; and this special feature is met in the markets of the raw material with a similar exhaustion. The reports in regard to the growing crop are conflicting. What with the certain effect of the floods in the Mississippi Valley, and tlie information from various sources in regard to the injury the young plant is receiving, serious apprehensions are entertained of another comparatively short crop. It is worthy of remark that conflicting interests generally take opposite views in regard to the future prospects of the growing crop. The hopes and apprehensions of the buyer and seller, combined with the natural disposition to embrace that view which is dic- tated by self-interest, must continue to characterize all the repoits upon cotton, cither from Europe or this side. But it is well for our European friends to have clearly before them the utmost cotton crop America can yield under the best possible conditions embraced in a wide area under cultivation, an early spring, a good stand in the field, a propitious summer, and a favorable autumn. Accepting these rare conditions as embraced within any one year, it is simply impossilJe for the United States to produce for commercial purposes, with the present supply of labor, beyond a certain amount of cotton. As the best staiTdard by which to arrive at this capacity for ' utmost production ' in America, we select the year 18.55-56. The commercial crop that season was 3,527,845 bales, from which must be de- ducted for cotton remaining over from the year previous, on hand in the interior, or in stock on the seaboard, say 250,000 bales. This leaves as the 'actual' or 'new' crop of 1855-56 the reduced amount of 3,277,845 bales. The season here taken, will be remeni- bered as the most fiivoraljle ever known to a large production. It was also stimulated in its growth by previously ruling high prices. Accepting as correct the generally-received data that the negro labor force in the cotton States increases at the rate of five per cent, per annum, would give fifteen per cent, increase for the three years, from 1856 to 1858-59. This increase of labor thrown into the cotton yield would seem to indicate 3,760,000 bales (more or less) as the utmost possible cajjacity of production for the year ending 1st Sep- tember, 1859. In explanation, it is woithy of remark that the increase upon the increase, which we have not estimated, in the three years, would make the production even larger. Yet we see in the succeeding years a falling oft' from the production of 1855-56 instead of an advance. The total commercial crop of 1856-57 was only 2,9:{9,519 bale.«, while the season just closed gives the limited yield of 3,113,962 bales. " The production of cotton in America is not therefore limited by soil. It is a question COTTON MANUFACTURE. 431 of labor, the negroes being almost exclusively the producers. Now a negro can only ' pick ' so many pounds of cotton a day, and no more. There is a certain number of negroes ; and these cannot be added to otherwise than by the natural increase of popula- tion already estimated.- They cannot be increased by immigration. The cotton picking season — that is, the cotton harvest — cannot extend beyond a certain number of days. Estimating, therefore, the largest number of negro laborers, the greatest amount of cotton per day to the hand, and tiic longest possible extension of the harvest or picking season, and we have the utmost possible production of the new crop. As before stated, the cotton year of 1855-56 presented all these favorable characteristics. Since then, the crop has i)eou reduced in exact proportion as either of these features were affected. In illustration, the following statement is instructive : " In 1844 the first receipt of new cotton on the sea board was on the 23d of July, the receipts at New Orleans on the 1st of September being 5,720 bales. The crop that year was considered large, being 2,394,503 bales. " In 1846 the first receipt of new cotton was on the Yth of August, and the receipts at New Orleans on the 1st of September only 140 bales ! Here notice the falling off in the total crop that year, the same being only 1,778,651 bales. " In 1848 we have a receipt on the 1st of September at New Orleans of 2,864 bales, and a total crop of 2,728,596 bales. "In 1849 (the succeeding year) we find the receipts at New Orleans on the 1st of Sep- tember to be only 477 bales, and the crop for that year falling off to 2,096,706 bales ! "In 1851 we find an unusually early receipt of the first bale and a receipt of new cot- ton at New Orleans ou the 1st of September of over 3,000 bales ! The crop that year was the largest ever grown up to that period, being over 3,000,000 bales ! " In 1852 (the succeeding year) we find the receipts at New Orleans on the 1st of Sep- tember to be 5,077 bales, being the largest receipt ever known up to that time ; followed in exact ratio by the largest crop ever grown, being 3,262,882 bales. " In 1853 we have a late receipt, followed by a diminished crop. " In 1854 we have another small receipt on the 1st of September, with a small total crop. " In 1855 we find an unusually early receipt of cotton, with the receipts at New Orleans on the 1st of September amounting to the unexampled figure of 23,382 bales ! An increased crop follows this early heavy receipt, being over 3,500,000 bales. "In 1856 (the next year) the receipts at New Orleans on the 1st of September were only 1,166 bales, and the crop, true to the principle of Labor, on which it depends so much, fell to 2,933,781 bales. " In 1857 the receipt on the 1st of September of new cotton at New Orleans was only 33 bales, followed by a short crop. " In this year the receipts up to date at New Orleans figure up 4,834 bales, embracing, of course, the flooded districts. " Referring to our annual tabular statement, it will be found that the ratio of increase in consumption keeps pace with increase of production, if indeed it does not exceed the latter." Growth and Conswnption of the United States. Total Consumed New „ South North Growth of and in Carolina. Carolina. Slates. Spinners' bands. lS:39-40 953,672 ' i:j(;,257 445.725 . 292,693 313,194 9,394 26,900 2,177,8.35 291,279 1 1S40-41 814,630 9:3,552 820,701 - 148,947 , 227,400 7,s65 21,800 1,634,945 297,283 mi-42 727,658 114,416 318.315 . 232,271 : 260,164 9,737 21,013 1,68.3,.574 i 267,8.50 l-i4-2-4:{ 1,060.246 , ICl.iiSS 431.714 - 299,491 351,658 9,039 15,639 2,378,875 325,129 1S43-44 8:32,172 ■ 145.5i!2 467,990 - 25.^.597 304,870 8,618 15,600 2,030,409 346.744 1844-45 929,126 : lls,69:3 517,196 - 29.'5,440 ' 426,361 12,487 2.5,200 2,394,503 389,006 1845-40 1,0:37,144 i 141,184 421,966 27,003 194,911 251.405 10,il:;7 16,282 2,100,.537 422.597 1S4G-47 7(15,979 i 127,8.V3 323,462 9.317 242, 7s9 850,200 6.im;i 13,991 1,778,051 427,967 184T-48 1,190,7:3:3 1 15:3,770 436,336 39,742 254825 1 261. (.52 1.5 18 8,952 2,347,6:54 .581,772 lsi4S-49 l,09-'5,790 ! 2"0,1S6 518,706 88 s27 891. .372 4,53,117 10,041 17,550 2,72s..596 518,039 ls40-.'-.O 781.SS6 1M.:344 850,952 31,263 .34:!,6:35 3S4265 11,n61 11.500 2,096,706 4.87,709 is50-r)i 9:i:3,:36y 181,204 451,748 45,820 822,376 887.075 12,928 20,737 2,3.5.5,257 404.103 is.-, I -52 1,:37;3,464 188,409 549,449 64,f).'-.2 .32.5.714 I 476,614 16.242 20.995 3,01.5.029 003,029 ls.-,2-r.:5 1,580,875 179,476 5W),029 8.^790 849.490 46:!.208 23,.t96 35,.523 .3.262.882 671.009 ]S.'j3-.'>4 I,:i46,925 15.\444 5:38,684 110,:325 816,011,5 416,7.54 11.524 84.366 2,930.027 6IO,.571 1854-55 1.2:32.614 1 :36,.597 454,.'-,95 80,7:37 878,094 499,272 26.1:39 8S.661 2,^47,3.39 598,534 18.'5.5-5fi 1,661,4:!:'. 111.104 C.->9.738 116.078 389.445 4S5.976 '.'6 OIK 84.67:1 .3.517.845 1856-57 1,435,0 10 I:i6,:3U 503,177 89,882 322.111 897.881 27,147 2s.:527 2,9:39,519 1857-53 1,. 576,409 122,351 522,364 145,286 282,973 406,251 2.3,999 34,329 3,11:3,962 432 COTTON MANTJFACTUEE. , ri-» . <^ o» la -* CO ir- 00 »o CO CO >o OS •^ CO •«i< •* lO o m CO d r-i 05 £- j:~ OS CO ■^ "* CI £- o IS' o 00 cS^ V o o eo_ CJ -cj<_ CI ■^ CJ_ I— I »o f-H OS_ 00 CO •^ -* CO o cf cf co" X- o' o cf oo" o Ci i-T »a" o" Jr^ o cf cs" IM CJ d Oi CO CO CJ CJ CO CJ CO CO CO CO 'd' 1* CO of o o o CO CI o 1— t o o o r- 00 OS oo CO CO o Pl o o to o CO o CO L3 oo CI OS >o 00 CS CO CD CO (N ■^ CO ■^ CO CO CO 1-' ■-I •-I r-l I-l CJ o « 5 h -»J 03 t- o o i^ C3 00 CS M< I— CJ «3 CO CJ ■^ o y—l t- CO S a Ol ^ CO CO 00 OS t- ■* 00 00 CO o OS ira J:^ CO b *^l 03_ 05_ CI CO cc_ o_ •*__ co^ CD__ oo Cs^ CO '*1. 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M w '-' '-' ^ ■"^ .2 ^ O t~ r^ »o CD o o o o o o o o o o o CJ CO S o co CO CO C5 o o o o o o o o o o o oo o CO CD ^ o_ »o t-;^ 00 lO CJ OS 00 '^__ CO CO OS "*_ -*-3 o CO lO cf t- >o -f CJ ir- CJ r- CO 1— 1 m 00 CO CO o" Cj T-H j:~ lO CO co lO CS CJ CJ 00 o CJ CJ 00 o CS CO CO ^ CI CI CI '-' CI '-' CJ CJ '-' CO CO CJ •* CO CO Tt< CO o 00 o i:~ CTJ o o o o o o o o o o o __, CS :n o o 03 C3 CO o o o o 00 o o o o c F— t •V ^ CO Cl^ o_ cc_ °°, CJ_^ CJ CJ CJ 00_ o_ t-_^ CJ^ l*^ OS_ t-^ CO CO « lo" ■^h' x-^ co" cf o" -+" o" o" co" ,— r oo" •*" cf co" ■^ cf oo" 00 03 00 05 *"* ^ 00 o CO i~ o ■* CO o CO CJ CO o CI ■>* 05 •* o o o o o o o o o o o CO o o CO CO CI o o o o o o o o o o o o \a -*_ CO 00 OS CD o ■*- lr-_^ CI 1:^ CJ^ o_ 00 CO CJ CO 2 t- cf CO CO CD C5 t— 1 ■* >o" t-^ -+1 CO a>' cf lO CO 00 CS CO o C3 ^ crs OS 1— x^ r~ oo OS 00 CO CD CI >a r- M o Ui ta 1(3 m o >o lO ^ 00 00 GO 00 00 O) 00 00 00 00 00 00 00 00 00 I-l 00 00 00 1 COTTON MANUFAOTUEE. 433 Price Of Cotton^ at Liverpool, at the dose of eac^ F ear. Description. 1840. 1 1841. 1842. 1 1843. j 1S44. { 1S45. j 1846. | 1847. 1848. d. d. ^d. d. d. d. d. rf d. rf. rf. rf. \d. d. \d. d. d. i 3+ 41 Now Orleans - 8+ 9 H 8* Si 9 4} 7 H 6 3+ 6+ 6+ 9+ 4 0+ 3+ 5+ Pernambuco - •Ji lOi Si 10 7i 8J 5f *i+ 4J tii 5f OJ, 7+ 8+ 6 7 4f 5* Bahia and M.aceio - - - - 5} 6i 4} H 5* 6 1 7+ Si! 5+ 6 4f •H Maranham a 10 !i n 6J 7f H 6i 4 b+ 4 6 1 6f 8+i 4i 0+ 4 •■' 1 Peruvian . . 5 6 4+ 6+ 4+ 5i: 6i 8 1 5} 6+ 4J •H Esryptian 11 14 9i 12+ 8 lOi 6 8 5 8 5^ 8 j 7i 10+1 5|. 8 5 7 Deinerara, &c. 11 la m 12 Si 10+ - - . - - 7 10+ 5i 8 4+ 5!- Common West In. - - - - 4+ H 4+ 5f 4 6 1 6+ Si! 4} 6 4 5 Laguira, &c. - . . - - - 4* M 4 4+ 4 4+ 6+ 7i 4+ 45 3+ 4 Cartliagena - - - - - - 8J 4i 3 3i 3+ 3+, 4i 5i 2J 31 Smyrna - - - . - . 4+ • - - - . • . . Surat ... 5i «i 5 6i 4} 5 3i 4f 2f 3+ 2+ 3f 4 5+ 2} 4 24 8 Bengal ... - - ... . 2i 3 • 4 4J 3 3+ 2f 3 Madras ... - - - - - 3+ 4+ 2i 3+ 2+ 3j' 4i 5+ 3 4j 2J 3 Description. 1849. 1850. 1 1851. 1 1852. 1853. 1854. 1855. j 1856. 1 1857. d. d. d. d. \d. d. d. <^. (?. d. d. * H i 8i; 4 5^ 4| 6i 4 6+ 3f 6 4V 6 1 6 8 ! 4 fit New Orleans - 6* 8 7 9i 4 6f 4i 7+' 4 7+ 3+ 7 4+ 7+; 6 8J 4 71 Pernambuco - «i 7 H 9 1 .5} 7 j 6f 7+ 6} 7 6 8 6 7J 7} 8+ 6J 7?- Bahia and Maceio - i 6^ 6} 6+ '} 7* Common 12 20 Seconds 81 8+ 71 7} 8 7! 9 7 fii 71 10 7+ 8 8+ 71 7^ ! 91 8 30 101 Oi y^ 9 9 8i 104 8 7J. 9 11 8} 9} 9f 8f 8} 10!- 9 40 fil 14 13 12J 1-.'+ m 121 14 Hi 9+ 12+ 13 10} Hi 12 11 11 12i 12+ Best Seconds ' 8 L 10 " 12. 20 9 8+ " 7f 7+ 7J- 9i 6* 5} 71 9 7 7+ 7} 6} 6} SI 7+ 101 9+ 10+ 9 8+ 8S 101 Ik 6} 81 10+ 8 8+ 8^ 7} 8f 9} 8+ 30 13 12 13 12 10 9} n\ 9 7+ 9+ 11 + 91 10+ 101 9} 9+ 11 9+ 40 ItH 15+ - 15+ 13+ 13J 151 12+ 11 13 13+ 11+ 12 t2i lU 11 + 13 13 Water Twist. 61 4 10 r 12 J 20 8 61 61 6+ 6+ GJ 7i .5} 5 c+ 81 H 5} 5.' 51 5+ 6} 61 9 81 71 7+ 7+ n 8'. 6} 6 7+ 9+ 6} 7} 71 6+ 6} 8 7 30 f'^t n 8+ 8+ 81 ^ 10 Vi 6+ 8+ |,.j 7+ SI 81 1\ 8 n 7} 40 10+ y+ 9+ 9 9j n 10+ V* H 91 '21 8 91 9+ 8+ 8J i('+ n* 50 12 11 11 10+ 11 10| 121 8} SI 10} 13} 9} 11 11 10 10 HI 1(1+ 60 14+ 12+ 12 12+ 13+ 12} 131 10 91 12+ l,^+ Kt} 12i 12 11 11 121 11 (0 16+ 16 13+ 14J 16 14?r 15} 12 11 1.3+ IVl 12+ 14 14+ 13 13 11+ 12 80 "1 18+ 17 15+ 16+ 18+ 181 19} 14+ 13 17 191 14+ 161 17 15+ 15 16 16 10 r 12J 20 9 7} 7+ 7+ 7+ 7} 9+ 6} 6+ 7 8} 5} 61 6 5} C 71 0} Best 9} 9i 8+ 8+ Si 8} lOJ 7} 6+ 8 10 71 81 7} 7 71 H 7+ 30 12 10+ 9+ 10 y+ 9| Hi Si 7 9 Hi 8 91 Sf 8 8+ 1(1 Si 40 12+ 11+ 101 111 10 10} 11} 9 7+ 10 121 '^i 10 94 8} 1 9* 11 lOf 50 13+ 12 12 11} 12 11} ]••;+ 11 8} 111 111 10 10 11 + ll»+ 10+ 11} 11 60 16 16 15 141 10+ 13+ l.-il 13 10 12} 16 1 + 13 '2i 11+ 11 + 12^ 'M |70 18+ 18 17 n+ !'<+ 16} 181 lt+ 12 14 17} 13 15 4 13+ 13+ 15 11+ l80 21 20+ 19 19+ 20+ 2n 22j; 16 14 18 20 I.H 17 17+ 1 16 15+ 16+ 16+ Vol. III.— 28 434 COTTON MANUFACTURE. The Growth, Consumption, and Export of Cotton from Wie United States during the laH Fifteen Years. Exported tc Crop of the Consumption in Ihe United Years. North of States. Great Britain. France. Europe. Countries. Total. \-yU-40 2,394.503 389,000 1,439.306 359,357 134,51 H 150.592 2,083.756 ls4o-4(J 2,100,537 422,597 1,102,369 359,703 60,692 118.028 l.t;6:-i.7!)2 1S46-4T 1.778,051 427.597 830,909 241.486 75,6b9 93.138 ],241,-i22 Is-tT-iS 2,347,034 010,044 1,. 324.265 279,172 120,343 134,476 1,858,201 l'^4S-49 2,728.590 642,285 1,5:37,901 368,259 165,458 1.^6.226 2.227,844 1^9-50 2,090,706 613,498 1,106,771 289,097 72,256 121,001 1,590,155 1S50-51 2.355,257 485,014 1,418,265 301,358 129,492 139,595 1,988,710 1 Sol -52 3.015,029 699.003 1,668.749 421.375 168,875 184,647 2,443.645 IS 2-53 3.202,882 803,725 1,736,800 426,728 171,176 193,636 2,528.490 1853-54 2,930,027 737,236 1,60.3,750 874.053 165,172 176,168 2,319,148 1S54-55 2,847,339 706,412 1.549,716 409,931 135,200 149,367 2,244,209 1 S55-56 3,527,845 770.739 1,921, .380 480, a37 304.005 248,578 2,954,806 lSo6-5T 2,939,519 819.936 1,428,870 413,857 245,793 164,632 2,252,657 1S57-5S 3,U3,9C2 595,562 1,809,963 384,002 216,145 181,342 2,589,968 Cotton Crop of the United States. Xew Orleans Mobile Florid.i Georgia . . • South Carolina - North Carolina - Virginia - - . Texas Tennessee, &c. • Total crop - - - Total crop of 1858, as above ... Crop of last year Crop of year before - Increase from last year Decrease from year be- fore ... 1857. 1,435,000 503,177 136.344 822,111 397.331 27,147 23.733 89.882 9,624 3,113,962 3.113.962 2,939,519 3,527,845 1,576,409 522,304 122,351 282.973 400,251 23,999 24,705 145.286 4,754 2,939,519 174,443 413,883 Export to Foreign Forts in 1S57-8. Xow Orleans bale; Mobile - - '■ Texas - - " Florida - - " Savannah - " Charleston - " North Carolina " Virginia - " Baltimore - " Philadelphia - " New York - " Boston - - " Total - Total last year Increase Great Britain. 1,010,716 265,404 33,933 25.771 149,340 192,251 495 164 995 110,721 14,110 To France and the Continent. 1.809.906 1,428,870 381,096 478,354 121.56S 16,404 18,356 107,153 37,100 1,553 780,489 823,787 16,710 1,495,070 387.032 50,838 25,771 167,700 299,404 495 164 995 147,821 15,663 2 590.4.'-.5 2,252,057 397,800 Consumption. Total crop of United States, IS.'SS - Add Stocks on hand^at the comnience- ment of the vcar 1st September, 1857 : — In the southern ports - - - 2.3,.590 In the northern ports ... 25,678 3,113,962 49.258 Makes a .supply of Deduct the export to foreign ports 2,590,455 Less foreign included - - 723 3,163,220, Stocks on hand at the close of the year 1st September, 1858: — In the southern ports - 57.604 In the northern ports - 45,322 2,589,732 102,926 Burnt at New York and Baltimore, and manufactured in Virginia - - - 18,377 ■2.711,035 Taken for home use 595,562 ToUil Crop of Bales, Quantity consumed bands of, Mncufac- turers. 1S57— 8 1856—7 18.55—6 1854—5 18.53— 4 1852—3 1851—2 1S50-51 l>;49-50 1,848—9 1847- 8 18-16-7 184.5—6 1844—5 lS4:?-4 1<42— 3 1841—2 1840—1 1839-40 18;?N— 9 1837—8 1836—7 1S:?5— 6 1S;34— 5 1833 — I 1832—3 3,11.3.962 2,939,519 3,527,845 2.847,-339 2,930,027 3.262.882 3,01.5,029 2,3,55.257 2,090,706 2,728.596 2..347.6:34 1.77S.651 2.100.537 2,394,503 2.030,409 2,378,875 1,68.3.574 1,6.34.915 2.177,a35 1,360,532 1,301,497 1,422,930 1..360,725 1,254.328 1,20.5,394 1. 070.438 Bales, 819,936 770,739 906,412 737,236 803.725 699,603 404,108 487,769 518,039 531,772 427,967 422,597 889.006 846,744 325,129 267,850 297,283 295,193 276,018 246,003 222,540 236,733 216,888 196,423 194,412 CURCUMA ANGUSTIFOLIA. 435 Stock in Ports, and Price of *' iliddling'''' New Orleans, at the Close of each Year. Egyptian, Ac. Equal to Price of Years. American. Brazil. East Indies. West Indies. ToUl. Week's Con- Middling, sumption. 3l8t Dec. Bales. (1. 1840 305,000 23,700 98,500 14,300 22,500 464,0(t0 19 6 1S41 219,600 46,100 157,600 24,700 31,400 539,400 24 5i 18J2 283,400 53,700 179,900 20,200 22.200 564,400 25 H 1S43 483,200 68,300 193,200 12,200 28,800 783,700 29 6i 1S44 544,900 62,700 239,200 13,700 41,400 901,900 33 4^ lS4o 693.100 52,300 241,000 6,100 67,900 1,060,400 35 4 1S46 302,800 23,700 157,400 4,500 57,400 545,800 18 7i 1S47 239,200 59,300 125,100 2,200 26,100 451,900 20 4f 1S4S 273.300 68,700 137,200 2,600 16,800 498,600 18 4 1849 316,400 95,200 107,800 2,000 88,000 559.400 18 6i 1850 273,900 68,700 143,400 1,300 35,100 522,400 18 t« 1851 245,800 49,500 172,000 1,300 2.5,900 494,500 15 4i 1853 360,700 54,600 133,100 5,800 10.3,200 657,400 18 5i 1S53 308,900 48,900 270,600 4.000 85.100 717,500 20 6; 1854 811,800 47,500 204,000 4,000 59,000 626,300 17 5 1855 236,300 63,100 133,100 3,500 50,500 486,500 12 5f 1856 178,130 27,170 99,480 700 27,170 332,740 8 7^ 1857 202,430 36,180 191,330 5,020 17,550 452,550 12 H — D. M. CRYOLITE. The mineral from which the metal Aluminium is obtained with the greatest facility. See Aluminium. It derives its name from Kpvos, ice, — from the circumstance of its being fusible in the flame of a candle. Its composition is — aluminium 13'00; sodium 32*8; fluorine 54-2. It was discovered at Arksutfiord, in West Greenland, by Giesecke, associated in gneLss with galena, pyrites, and spathic iron. It is now obtained in large quantities. CRYSTAL. A crystal is a body which has assumed a certain geometric form. It is produced by nature, and may be obtained by art. The ancients believed quartz to be water converted into a solid by intense cold, and hence they called that mineral crystal, from KpvaraWos, ice. This belief still lingers, many persons thinking that rock crystal is, in fact, congealed water. The term crystal is now applied to all solid bodies which assume certain regular forms. A crystal is any solid bounded by plane surfaces symmetrically arranged. Each mineral has its own mode of crystallization, by which it may be distinguished, and also its own peculiarity of internal structure. We may have a mineral in a considerable variety of external forms, as pyrites, in cubes, octohedrons, dodecahedrons, &c. ; but these are all resolvable into a simple single type — the cube. Thus galena, whatever external form it may assume, has an internal culDical structure. Fluor spar, usually occurring in cubical forms, may be cleaved into a regular octohedron. A little reflection will enable the student to see that nature in her simple ar- rangements maintains an unvarying internal type, upon which she builds up her varying and beautiful geometric forms. There are certain imaginary lines which are called the axes of the crystal : these may be Rectangular and equal, as in the cube. Rectangular and one unequal, as in the right square prism. Rectangular and three unequal, as in the right rectangular prism. The three axes unequal, vertical inclined to one of the lateral, at right angles to the other, two lateral at right angles with one another, as in the oblique rhombic prism. The three axes unequal and all the intersections oblique, as in the oblique rectangular prism. Three equal lateral axes intersecting at angles of 60° and a vertical axis of varying length at right angles viith the lateral, as in the hexagonal prism. Upon these simple arrangements of the axial lines all the crystalline forms depend, the particles of matter arranging themselves around these axes according to some law of polar- ity which has not yet been developed. CURARINE. An alkaloid existing in a black resinous matter called ciirari, used by the American Indians for i)ois()iiing their arrows. It is singular that while the curari poison is absolutely fatal when introduced, even in small doses, into a wound, it is inert when swallowed. Its composition is unknown, but it appears to be produced from one of tlie Stri/chnea'. — C. G. W. "CURCUMA ANGUSTIFOLIA. The narrow leaved Turmeric. (East IndiMii Arrow Root.) This plant is found in the forests, cxtentiing from (he lianks of the Loiia to Nag- I)ore. At Hhagul[)ore the root is dug up and rul>lied on a stone or l)ed in a mortar, snid afterwards rubbed in water witli the liand and strained through a cloth ; tlie feeula having 8ub.sided, the water is poured off, and the tikor (feeula) dried for use. The East Indian 436 CURLING STONE. arrow root is a fine white powder, readily distinguishable, both by the eye and the touch, from West Indian arrow root. To the eye it somewhat resembles a finely-powdered salt, (as bicarbonate of soda or Rochelle salt.) When pinched or pressed by the fingers, it wants the firmness so characteristic of West Indian arrow root, and it does not crepitate to the same extent when rubbed between the fingers. — Percira. At Travancore this starch forms a large portion of the diet of the inhabitants. CURLING STONE. A stone used in Scotland in playing the national game of curling, which is practised upon the ice during the winter. The stone is made of some hard pri- mary rock. That of Ailsa Craig, in the Firth of Clyde, is very celebrated. Ailsa Craig consists of a single rock of grayish compact felspar, with small grains of quartz, and very minute particles of hornblende. — Bristoiv. CYANATES. The combinations of the various bases with cyanic acid, (C'lINO'.) The cyanate of potash, C"NKO^, is employed for the preparation of artificial urea. There are two modes of preparing cyanate of potash, both of which yield a good product. The first is that of Clemm, the second of Liebig. 1. 8 parts of ferrocyanide of potassium and 3 parts of carbonate of potash are intimately mixed and fused, care being taken not to urge the heat too much. The fluid mass is allowed to fall somewhat in temperature, but not to such an extent as to solidify ; 15 parts of red lead are then added by small portions. The crucible is now to be reheated with stirring, then removed, and the contents poured on to a clean iron plate. 2. The cyanide of potassium of commerce (prepared by the method described in the article under that head) is to be melted in an iron crucible or ladle, and 3^^ parts of dry litharge in fine powder are to be added with constant stirring. When the lead has all collected at the bottom, the whole is poured on to an iron plate. The mass obtained by either of the above processes is to be reduced to powder, and boiled with repeated quantities of alcohol, until no more cyanate is extracted. This may be known when the alcohol filtered from the residue no longer yields crvstals of cyanate in cooling. — C. G. W. CYANIDES. The combinations of cyanogen with metals or other bodies. It has been remarked in the article Hydrocyanic Acid that cyanogen, C'N, is a compound salt radical, analogous to the halogens chlorine, iodine, and bromine. Like the latter it unites with metals without the intervention of oxygen, and with hydrogen to form a hydracid corre- sponding to the hydrochloric, hydriodic, and hydrobromic acids. The cyanides are both an important and interesting class of salts. The most important is the cyanide of potassium. The latter is formed under a great variety of circumstances, especially where carbonate of potash is heated in contact with carbonaceous matters. The nitrogen to form the cyanide in the greater number of instances is principally, and in a few entirely, derived from the atmosphere. Many chemists have experimented on this subject, and their results are by no means in harmony ; but thus much is certain, that success or failure depends solely upon the circumstances under which the experiments are conducted. It has been shown that, when carbonate of potash mixed with charcoal prepared from sugar (see Carbon) is exposed to a very high temperature in a current of nitrogen gas, the potash in the carburet is, at times, absolutely converted into cyanide, not a trace of carbonic acid remaining. Ex- periments of this class, when made with animal charcoal or coal, are less conclusive because those matters contain nitrogen. But even then the amount of cyanogen found is out of proportion to the quantity of nitrogen in the coal or other carbonaceous matters. In fact it would seem that the presence of a certain quantity of nitrogen in the coal, &c., exercises a predisposing tendency on the nitrogen of the air so as to induce its combination with car- bon with greater facility than would be the case if pure carbon were employed. Cyanide of potassium has been found on more than one occasion oozing from ajjcrtures in iron- smelting furnaces. In fact it is produced in such abundance at one furnace in Styria as to send into the market for sale to electro-platers. Cyanide of potassium is largely prepared for the use of electro-platers and gilder.s. The proportions of the materials used are those of Liebig, who first made known the process. The modes of manipulation, however, differ in the details in all laboratories. The following method can be recommended from the ex- perience of the author of this article as giving a white and good product. It can, more- over, be worked on a very large scale. The ferrocyanide of potassium and salt of tartar are to be separately dried, pulverized, and sifted through cane sieves. The salt of tartar must be free from sulphates. To 8 parts of dry fen-ocyanide of potassium 3 of dry salt of tartar are- to be added, and the two are to be incorporated by sifting. A large and strong iron pot is then to be su.spended by a chain from a crane, in such a position that it can be lowered into the furnace and raised with ease ; there must also be an arrangement to en- able the pot to be arrested at any desired height. The pot being heated to redness, the mixture is to be thrown in by small portions until the vessel is half full ; the heat being al- lowed to rise gradually until the whole flows pretty quietly. During the fusion the con- tents are to be stirred with a clean iron rod to promote the aggregation of the spongy sedi- ment. As soon as the rod, on being dipped into the fused mass and removed, brings with it a pure, white, porcelain-like product, the operation may be regarded as terminated, and CYANOGEN. 437 the pot is to be raised from the fire by means of the crane and sling in a slightly inclined position. One of the operators now liolds a large clean iron ladle under the edge of the pot, while another elevates the latter with the aid of tongs, so that the ladle becomes filled. The contents of the first ladle are then poured olf into another held by the assistant who tilted the pot. The latter then pours the contents of his ladle into a large, shallow, and brilllautly-clcan brass basin standing in another containing a little water so as to cool the fused cyanide rapidly. Extreme care must he taken to prevent even the smallest drop of water from finding its way into the brass vessel, because on the hot cyanide coming in con- tact with it an explosion would occur, scattering it in every direction, to the great danger of the persons in the vicinity. The two ladles are to be kept very hot, by being held over the fire until wanted, in order to prevent the cyanide from chilling until it is poured into the brass basin. The latter should be about 18 inches in diameter and 1^ deep. It should be quite flat-bottomed. The object of so many pourings off is to prevent any of the sedi- ment from finding its way into the product, and thus causing black specks in it. The pot, on being emptied as far as convenient, is to have the sediment removed and a fresh charge inserted. As soon as the coke of cyanide is cool, it is to be broken up into moderate-sized pieces and placed in dry and well-closed jars. The cyanide of potassium possesses great points of interest for the technical and theoretical chemist. It is the salt from which an immense number of compounds of im- portance may be obtained. Very large quantities are made for the purpose of preparing the auro- and argento-cyanides of potassium for the electro-platers and gilders. Auro-ci/anide of potassium is capable of being formed in several ways. The following are convenient processes. The selection of a mode of preparing it will depend upon the circumstances under which the operation is situated. 1. By the battery. This process is perhaps the most generally convenient and economical for the electro-gilder. A bath is prepared by dissolving the best commercial cyanide of potassium in good filtered or distilled water. The best salt is tliat sold under the name of "gold cyanide." A Daniell's battery of moderate size being charged, two plates of gold are attached to wiresf and connected with it. The larger, which is to be dissolved, is attached to the positive, and the smaller, which need be but the size of a flattened wire, to the negative pole. The action of the bat- tery is kept up until the desired amount is dissolved. It is easy to remove the plate used, dry and weigh it at intervals so as to know the proper time to stop the operation. 2. Te- roxide of gold (prepared with magnesia) is to be dissolved in a solution of cyanide of potassium. Argento-cijanide of potassium. — This solution is easily prepared for the electro-plater by the following process : Metallic silver is dissolved in nitric acid and the solution evapo- rated to dryness. The residue is dissolved in distilled water and filtered. To the solution cyanide of potassium, dissolved in distilled water, is added, as long as precipitation takes place, but no longer. The precipitate is filtered off on calico strainers, and well washed with distilled water. It is then to be dissolved in solution of cyanide of 91 la potassium and diluted to the desired strength. The solution is frequently dark-colored at first, but it becomes colorless in a few hours, and should then be filtered from a small black precipitate which will be obtained. Many operators neglect the filtration and washing of the precipitated cy- anide of silver, and merely continue the addition of the solution of cyanide of potassium to the nitrate of silver until the precipitate at first formed is re-dissolved. The first method is however to be preferred. Some, instead of precipitating with cyanide of potassium, do so with solution of common salt, and then, after washing off the precipitated chloride of silver, dissolve it in cyanide of potassium. Argento-cyauide of potassium can also be pre- pared with the battery by the process mentioned under auro-cyanide of potassium ; this method is so convenient where the proper apparatus is at hand, that few professional electro-platers would use any other method. Daguerreotype artists who silver their plates, or rather, re-silver them, would find the battery process too cumbersome, and should, therefore, use a solution of argento-cyanide of pota^ssium prepared by the first method. In order to suspend Daguerreotype plates in the bath, the little con-' trivance figured in the margin, fig. 21 la, will be found most convenient. It merely con- sists of pieces of copper wire twisted together and fcjrmed into a grapnel at the lower end. It acts like a spring, and liolds the plate so firmly that there is no fear of its falling out, even if the apparatus be subjected to severe vibration. — C. G. W. CYANIDE OF POTASSIUM. See Cyanides. CYANOGEN, C'N. A compound salt radical, analogous in its character to chlorine and the other halogens. It was the first body discovered possessing the characters of a compound radical, and the investigations made upon it and its derivations have thrown more light upon the constitution and proper mode of classifying organic substances than 438 CYMOPHANE. any other researches whatever. In consequence of its acting in all its compounds as if it were a simple body or element, chemists generally have acquired the habit of designating it by the symbol Cy. Like the haloids it combines with hydrogen to form an acid, and with metals, without the necessity for the presence of oxygen. For a few illustrations of its analogies with chlorine, &c., see Hydrocyanic Acid. In the article Cyanides several of the conditions under which it is formed have also been pointed out. The modern French chemists of the school of Gerhardt very justly regard cyanogen in the light of a double molecule, thus, Cy Cy, or C^N^ The reason of this is because most of the phenomena of organic chemistry are more easily explained by the use of four-volume formula; than any others. This latter mode of condensation has been shown by M. Wortz, in his admirable work on the compound radicals, to undoubtedly exist in the case of radicals belonging to the strict hydrogen type, not as ethyle and its homologues ; and numerous theoretical and experimental results are in favor of the supposition that all radicals in the free state are binary groups. If we assume the truth of the above hypothesis, we shall regard cyanogen in the free state as a cyanide of cyanogen, analogous to hydrocyanic acid, which is a cyanide of hy- drogen. Cyanogen may very conveniently be prepared by heating cyanide of mercury in a retort of hard glass. A considerable quantity of the gas is given off, but a portion remains be- hind in the state of paracyanogen. The latter substance is a black matter, the constitution of which is l)y no means understood. It has, however, the same composition in the bun- dled parts as cyanogen itself, and is therefore isomeric with it. Cyanogen is a colorless combustible gas with a sharp odor. Its density is 1 'SI. Hauy requires for two volumes 1"80. If cooled to a temperature of between — 13° and — 22° F., it liquefies into a transpaient, colorless, and very mobile fluid having a specific gravity of 0'866. A little below 22' the fluid congeals to a mass resembling ice. The flame of cy- anogen is of a pale purple or peach blossom color. Some of the»proporties of cyanogen are very remarkable, and quite distinct from those of the true halogens. For instance, it combines directly with aniline to produce a body having basic properties. The latter is called cyaniline, and is formed by th* coalescence of two molecules of c.vanogen with two of aniline, the resulting formula being, consequently, C^^II^N*. There are a variety of singular compounds produced by the action of cyanogen and its halogen compounds upon aniline ; they have been studied with remarkable skill by Hofmann.— C. G. W. CYMOPHANE. A variety of Chrysoberyl, which exhibits a peculiar milky or opales- cent appearance. When cut en cabochon, it shows a white floating baud of light, and is much prized as a riag stone.---H. W. B. J> DAGUERREOTYPE. The progressive ad^-ance of this branch of the photographic art, though of great interest, cannot be dwelt on in this place. Those who are interested in the inquiry, will find the information fully detailed in IlunVs Manual of Photocjrapliy, 5th edi- tion, 1857. It will 1)0 sufficient in this work to detail the more important improvements which have become generally adopted. The first advance of real importance was made by Mr. Towson, of Devonport, who has since that time distinguished himself by the introduc- tion of his system of Great Circle Railing. Mr. Towson suggested the use of enlarged lenses, and by acting with such, Dr. Draper, of New York, was the first to procure a por- trait from the life. Still this was a tedious process, but in 1840 Mr. Goddard proposed the use of bromine of iodine, by which infinitely increased sensibility was obtained. From that time the Daguerreotype was generally employed for portraiture, until the facilities of the collodion process drove it fiom the field. The improved manipulation now resolves itself into Carefidly polishing the silver plate, and the application finally of the highest polish by the use of a buffer, the best form being that employed by M. Claudet. lu a box on a roller, to which there is a handle, ^^(/. 212, is placed a long piece of drab- 212 :i;iiiii|l}|l|l||l|IV,i DAGUEEREOTYPE. 439 213 colored velvet, which can be drawn out and extended by means of a second roller upon a perfectly flat table. The first foot or two, for example, is drawn out ; the plate which has already received its preliminary polishing is placed face downwards, and being pressed close with the fingers a rapid circular motion is given to it, and in a few minutes it receives its highest lustre. As the velvet becomes blackened by use, it is rolled off, the portion re- maining in the box being always perfectly clean and ready for use. The iodizing process follows : and for this purpose a box similar to that represented will be found to be very convenient, {Jig. 213.) This iodizing apparatus consists of a square box with a closely-fitting cover g, false sides are placed at an angle with this box, a cup d at the bottom contains the iodine, which is covered with a thin gauze screen J J. c is a cover which confines the iodine when it is not required for the plate ; this dividing the box into two parts, H H, and k k, the former being always full of iodine vapor. When it is desired to iodize a plate, the cover c is removed, the silver plate is placed at E, and the cover g closed. The plate is thus placed in the iodine box until it acquires a fine straw yellow color. In another box is placed either bromine or some one of the many ac- celerating fluids. If bromine, or any bromide is em- ployed, the plate should remain until it becomes of a rose color. As a general rule, if the yellow color produced by iodine be pale, the red should be pale also ; if deep, the red must incline to violet. The proper time for exposing a plate to any of those chemical substances which are destined to produce the sensitive film, must vary with the temperature, and it can only be determined by experience. The sensitive plate is now removed to the camera obscura, for a description of which see Photography. It is scarcely necessary to say, that the plate must be preserved in perfect darkness until ex- posed to the image in the camera. A few seconds when the plate is properly prepared will be found amply sufficient to produce the best effect. The impression must be developed in the mercury box {fg. 214) in the manner de- scribed by Daguerre. This mercurial box consists of a box mounted on legs, having a close-fitting cover a, and an iron bottom in which is placed the mercury c, and a small thermometer f to indicate the proper temperature, g is a piece of glass let into the side of the box through whicti the Da- guerreotype plate H, fixed in the frame b, can be seen. D is a spirit lamp, and i the platform on which it stands. The subject is eventually fixed by the use of hyposulphite of soda, which removes the bromo-iodido of silver and leaves a picture produced by the con- trast between a combination of the silver and mer- cury, and the surface of the unchanged, polished silver. The application of chloride of gold to the finished picture was introduced by M. Fizeau. Chloride of gold applied to the picture has the effect of fixing and enlivening the tints. A small grate being fixed by a clamp to the edge of a table, the plate is laid upon it with the image uppermost, and overspread evenly with solution of chloride of gold, by means of a fine broad camel hair brush, with- out letting any drop over the edge. A spirit lamp is now brought under the plate, and moved to and fro till a number of small steam bubbles appear upon the image. The spirit lamp must be immediately with- drawn. The remainder of tlue chloride solution must be poured back into the phial, to be used on another occasion. It is lastly to be washed and examined. This operation has been repeated three or (bur times with the happiest effect of giving fixity and force to the picture. It may then be wiped with cotton without injury. The process of coloring these pictures is a purely artificial one, which, while it destroys the beauty of the photograph, does not in any way improve it as a picture. Daguerreotype Engraving. — Several processes for etching the Daguerreotype plate were 214 440 ' DAKAR GUM, or DAMMARA RESIN. introduced with more or less success. Professor Grove produced a few good engravings by the action of voltaic electricity. Berard and Becquerel were also enabled to produce some promising results by a similar process. The following process by M. Claudet was car- ried out to some extent with every prospect of success. The new art, patented by M. A. F. J. Claudet on the 21st of November, 1843, was established on the following facts : A mixed acid, consisting of water, nitric acid, nitrate of potash, and common salt in certain proportions, being poured upon a Daguerreotype pic- ture, attacks the pure silver, forming a chloride of that metal, but does not affect the white parts, which are produced by the mercury of the picture. This action does not last long. Water of ammonia, containing a little chloride of silver in solution, dissolves the rest of that chloride, which is then washed away, leaving the naked metal to be again attacked, especially with the aid of heat. The metallic surface should have been perfectly puri- fied by means of alcohol and caustic potass. For the rest of the ingenious but complex details, see NewtorCs Journal^ C. S. vol. xxv. p. 112. — See Actinism, Collodion, Pno- TOGRAPHY. DAMAR gum, or DAMMARA RESIN. A pale yellow resin, somewhat resembling copal, and used like it in the manufacture of varnishes. Dammara resin is said to be de- rived from the Pinus dammara alba of India. A Dammara resin is also imported from New Zealand, which is the product of the Damtnara Anstralis. Under the name of Cow- die resin, it is said to be used extensively as a varnish in America. " Damar is easily dissolved in oil of turpentine, and when carefully selected is almost colorless ; it makes a softer varnish than mastic ; the two combined, however, form an almost colorless varnish, moderately hard and flexible, and well suited for maps and similar purposes." — Holtzapffel. DAMASCUS BLADES. The characteristics ascribed to the real Damascus blades are extraordinary keenness of edge, great flexibility of substance, a singular grain of fleckiness always observable on the surface, and a peculiar imtxki/ odor given out by any friction of the blade, either by bending or otherwise. The author of " Mamifactures in Metals''' remarks : " A gentleman who purchased one of these blades in the East Indies for a thousand piasters, remarked to the writer of this volume that, although the instrument was very flex- ible, and bore a very keen edge, it could not with safety be bent to more than 45° from the straight shape, and it was not nearly so sharp as a razor, yet, wielded by a skilful hand, it would cut through a thick roll of sail-cloth without any apparent difficulty ; a feat which could not be performed with an ordinary sword, nor, it should be observed, by the sabre itself in an ordinary hand, though the swordsman who tried it could, it appears, do nearly the same thing with a good European blade." Emerson, in his letters from the JJgean, says: "I have seen some blades (scymitars) which were valued at 200 or 300 dollars ; many are said to be worth triple that sum, and all retain the name of Damaxcui^, though it is by no means likely tliat they have been manufactured there. The twisting and intertwisting of the fibres of the metal are consid- ered as the tests of excellence, but I have never seen any possessed of the perfume said to be incorporated with the steel in the real Damascus blade." The production and use of damask steel have received much attention from the late Gen- eral Anossoff, of the Corps of Engineers of the Imperial Russian army, and Master of the Fabric of Arms at Zlataoust, in Siberia. His researches and successful practice have be- come matters of history. Steel helmets and cuirasses were formed of cast and damascened steel, intermixed with pure iron, a mixture supposed to combine toughness and hardness in the greatest possible degree. At different periods these works have been visited, separately, by two English travellers. Major Abbott of the Bengal Artillery, and Mr. Atkinson, who have recorded the results •of observation, experiment, and conversational intercourse, and they state severally their conviction that the damask steel produced by Anossoff' rivalled in beauty and ex- cellence any works they had ever seen in other lands. They accord to Anossoff the honor of being the reviver of the art of making damask steel in Europe, while they declare the Russian natural damask steel is not approached by the fabrics of any eastern nation now existing. The Siberian swords and daggers were compared and tried with the choicest specimens, and found equal to the blades of Damascus and the sabres of Khorassan ; and while these valued articles might have l)ecn selected from numbers manufactured by chances of skill and material, Anossoff" united chemical analyses of ores and steel, and records of observa- tions on progressive stages, to give a true history of the means to explain and insure suc- cess. DAMASCUS GUN-BARRELS. See Fire-Arms, vol. i. DECKLE, name given by the paper maker to a thin frame of wood fitting on the shal- low mould in which the paper pulp is placed. DECOMPOSITION. 441 DECOMPOSITION". The separation of bodies from each other. The methods em- ployed are almost imiumerable, and usually depend on the special reactions of the matters under examination. We shall consider a lew of the most striking cases in both the grand divisions of the science, viz., inorganic and organic chemistry. In each instance we shall, for the sake of convenience, subdivide into the three classes of acids, alkalies, and neutral bodies. Previous, however, to this, we must glance at some of the reactions of which chemists avail themselves in separating the elements. The decomposition of ordinary me- tallic salts, with tlie view of making a qualitative analysis of a more or less complex mix- ture, is a problem, in general, of extreme simplicity, and directions for the purpose are to be found in all the numerous works on qualitative analysis. The principle on which the modern methods of qualitative analysis are founded, is the separation of the metals in the first place into large groups by certain reagents, and then by means of others, to subdivide into smaller groups, in which the individual metals can be determined by special tests. For the sake of simplicity, we shall only consider the more commonly occurring metals. The general reagents, by which the first subdivision is effected, are hydrochloric acid, sul- phuretted hydrogen, sulphide of ammonium, carbonate of ammonia mixed with chloride of ammonium, and finally phosphate of soda. The substance in solution is treated with hy- drochloric acid, by which mercury, silver, and lead are removed. The mercury will only be perfectly removed if it exists entirely in the state of a subsalt. Lead is only partially precipitated, and will be subsequently found in the next group. The precipitate by hydro- * chloric acid is to be boiled with water, which will remove the chloride of lead, and leave the chlorides of mercury and silver. The latter may be separated by means of ammonia, which will dissolve the chloride of silver and convert the mercury into a black powder, in which the metal can be detected by special tests. The fluid filtered from the precipitate by hydrochloric acid is to have a stream of hydrosulphuric acid gas passed through it for a considerable time, or until no more precipitation occurs. By this means antimony, arsenic, tin, cadmium, gold, mercury, silver, lead, bismuth, and copper are thrown down, and must be separated from each other by special processes. The filtrate from the precipitate by hydrosulphuric acid is to have ammonia added in slight excess, and then a solution of sul- phide of ammonium as long as any precipitation takes place. By this means nickel, cobalt, iron, manganese, zinc, alumina, and chromium are thrown down; also baryta, strontia, ami lime, if they happen to be in combination with phosphoric, oxalic, or boracic acids, or if united to fluorine. From the filtrate, carbonate of ammonia mixed with chloride of ammo- nium, precipitates baryta, .strontia, and lime. The filtrate from the last precipitate can only contain magnesia, or the alkalies. The above brief description of the mode of dividing the metals into groups will be sufficient to give an idea of the processes employed for decom- posing complex mixtures into simple ones. Inorganic acids are usually removed from metals by converting the latter into an insol- uble compound, while the acid remains in solution either in the free state or combined with a, body of such a nature as not to mask the reactions of the acid with reagents. This is often done in the laboratory by boiling the metallic salt with an alkaline carbonate. The metals are, consequently, either converted into oxides or carbonates insoluble in water, while the acid unites with the alkali to form a soluble salt capable of being obtained by fil- tration in such a condition as to permit the nature of the acid to be made known by means of appropriate tests. It is usually necessary to neutralize the solution carefully before test- ing for the acid. It is seldom necessary in researches to reduce inorganic alkalies to their elements, their constitution being usually ascertained by converting their constituents into new forms capa- ble of being weighed or measured with accuracy. If, for instance, it was necessary to as- certain the constitution of sulphuric acid, it would be sufficient to determine the quantity of baryta contained in the sulphate. On the other hand, acids susceptible of assuming, when pure, the gaseous condition, may have their constitution determined by decomposing a known volume with a substance capable of combining with one ingredient and libciating the other in the gaseous state. Thus hydrosulphuric acid may be analyzed by heating it with potassium, which will remove the sulphur and liberate the hydrogen. In decomposing inorganic alkalies with the view of separating the metals contained in them, we usually have to avail ourselves of very powerful affinities. This arises from the fact, that the substances in question are, generally, produced by the union of a metal with oxygen, the metal having so strong a tendency to combine with that element, that mere exposure to the air is sufficient to determine their union into a compound of great stability. In order, therefore, to decompose the alkalies of this class, it is necessary to find some sub- stance having a powerful tendency to combine with oxygen under certain conditions. Now it has been found that carbon, if raised to an exceedingly high temperature, and employed in great excess, is capable of removing the oxygen, even from such bodies a.s potassium and sodium, the affinity of which for oxygen is very great. Inoi'ganic neutral bodies are generally decomposed either by the ordinary processes of 442 DECOMPOSITION. analysis, or, where the neutrahty arises from the substance under examination bein"- a compound of an acid and a base, by separating the two by treatment with a reagent capable of combining with one to the exclusion of the other. This is a process frequently available in quantitative analysis. As an illustration we may take the decomposition of the carbo- nates by a mineral acid in an apparatus which permits the carbonic acid set free to be accu- rately estimated by weighing. (See Carbonates.) Another instance of the decomposition of a neutral body, by treating it with a substance capable of combining with one of the constituents and separating the other in a free state, is the decomposition of sulphate of potash by baryta. If a solution of the salt be boiled with excess of solution of baryta, sul- phate of baryta is produced and caustic potash set free. The excess of baryta is removed by boiling in the air until the whole of the latter base is converted into the insoluble carbo- nate. A precisely analogous process is the ordinary mode of preparing caustic potash by boiling its carbonate with quicklime. Neutral bodies are frequently, however, so constituted that the neutrality does not arise from the circumstance of an acid being saturated with a base, but from the energies of two elements being, to some extent, satisfied by the fact of their being in combination. Thus, water is a neutral substance, nevertheless it may be decomposed by a variety of processes, several of which are susceptible of quantitative precision. In the first place, it may be decomposed by passing steam over a metal capable of uniting with its oxygen with liberation of the hydrogen. It may also be electrolyzed and the two gases separately obtained. Organic or inorganic neutral salts may, at times, be very completely and simply decom- posed by means of the battery. Not only are the various processes in electro-metallurgy founded on this principle, but it has even been practically applied to the quantitative esti- mation of the metals in ores. The electrolysis of the neutral salt of the great series of or- ganic acids of the general formula C'E'^O* has thrown great light on some previously ob- scure points in the radical theory. The decompositions undergone by organic substances in contact with reagents are so manifold, that the limits of this work preclude the possibility of doing more than glancing at a few of the most general and interesting. Peihaps of all the modes of inducing the breaking up of more complex into simpler substances, the application of heat is the most remarkable for its power and the varied and opposite character of the substances produced. It has been shown that, as a decomposing agent, heat possesses no special function. From complex organic molecules all classes of substances are formed. Individual substances be- longing to every chemical type are, therefore, found among products of destructive distilla- tion. Acids, alkalies, and neutral bodies of every kind are formed, and some of the most interesting and beautiful bodies known to chemists are found in the uninviting looking tar of coal. Let us illustrate this by a glance at a few of the coal-tar products. Among the acids are the oxyphenic, carbolic, and crcsylic. The alkaloids represented are methyla- mine, ethylamine, propylamine, butylamine, amylamine, pyridine, picoline, lutidine, colli- dine, parvoline, chinolinc, Icpidine, cryptidine, and aniline. Among hydrocar))ons, ben- zole, toluole, xylole, cumole, cymole, propylc, butyle, amyle, caproyle, caproylene, cenan- thylene, napthaline, anthracene, chrysene, pyrene, &c., &c. This list, probably, does not include one-half of the substances produced from coal by the decomposing and recomposing influence of heat. Mineral acids exercise a powerful decomposing influence on organic substances. Of these the nitric and sulphuric are the most commonly used. Nitric acid is especially active, owing to its twofold action. By virtue of its oxidizing tendencies, it breaks up great num- bers of substances into more simple and less carburetted derivatives, and the hyponitric acid produced by the removal of one of the atoms of the oxygen of the acid frequently enters into the resulting compound, a substitution product being the final result. In the latter bodies produced in this manner the hyponitric acid (NO'') generally replaces hydrogen, the original type remaining unaltered. The production of oxalic acid from sugar ; succinic, lipic, adipic, pimelic, suberic, &c., acids from oily and fatty matters by the action of nitric acid, are examples of its oxidizing power ; while the formation of nitrobenzole, and bodies of more or less analogous character, presents instances of the replacement of hydrogen by hyponitric acid. Sulphuric acid owes its decomposing power to its extreme tendency to combine with water. Many of the less stable organic liodies are, by this means, absolutely broken up, so that the resulting products are of a character too indefinite to allow of the changes being expressed by an equation which shall render a true account of all the substances directly or indirectly formed. On the other hand, the action may be so controlled by the careful regulation of the temperature and strength of the acid that products may be ehmi- nated which are themselves totally lirokcn up and destroyed by an acid of greater strength. The production of grape sugar by the action of sulphuric acid on starch, or lignine, may be taken as an example. It not unfrequeutly happens, that the sulphuric acid unites with the substance acted on to form a conjugated compound. Benzole, and many other hy- DESICCATION 443 drocart)ons, as well as oxidized bodies, behave in this manner with concentrated sulphuric acid. Chlorine and the other halogens are powerful decomposing agents, acting chiefly by vir- tue of their affinity for hydrogen. The principal effects produced by them arc oxidation and substitution. The oxidizing action of the halogens arises from the decomposition of water ; the hydrogen combining with the chlorine, &c., to form an hydracid, and the free oxygen uniting with the other substances present. ' The above sketch will sufficiently indicate some of the most usual methods by which the decomposition of organic and inorganic bodies is effected ; but hundreds of other de- composing agencies are at the call of the chemist, when any phenomena involving the dis- ruptions of compounds are to be investigated. — C. G. W. DEODORIZERS. Bodies which have the power of depriving fetid and offensive effluvia of their odors. There appears to exist a general idea that these substances are, all of them, equally disinfectants. No greater mistake can be made than to suppose that because a pre- paration has the power of removing a disagreeable smell, that therefore it has removed all the elements of infection or disease. See Disinfectant. To disguise unpleasant odors, fumigation is employed, many of the fragrant gums are burnt, and fumigating pastilles employed. It is also a common practice to burn lavender and brown paper, but these merely overpower or disguise the smell ; they do not in any way act upon the noxious effluvia. DERRICK CRANE. The term Derrick is applied to a temporary crane, consisting of a spar supported by stays and guys, carrying a purchase for loading or unloading goods on shipboard. The Derrick crane is somewhat similar in its plan, the projecting iron beam or derrick of which can be raised or lowered to any desired angle. DESICCATION. The act of drying. Davison and Symington patented a process for drying or seasoning timber, by currents of heated air. Even after wood has been dried in the ordinary manner, it contains much moisture, which it is still necessary to remove. The patentees have given some curious re- sults of this desiccating process : — Temperature of air 214°. Yiolin wood. Original weiglit. Weight after seasoning. Moisture removed. 6 pieces small and thin ... 2 pieces larger ..... 2 pieces larger ..... 3-38 10-56 25-25 2-87 9-5 22-93 8- per cent. 10-1 do. 9-25 do. Original weight. 100° after 6 hours. 120' after 10 hours. 150° after 20 hours. ISO" after 30 hours. 230° after 38 hours. Per cent. Oak - 1-84 1-76 1-71 1-59 1-56 1-51 18-1 Red pine 1-5 1-4 1-38 1-33 1-28 1-25 16-0 Birch . 1-2 1-09 1-05 1-01 •99 •97 19-2 Mahogany 1-21 1-14 1-09 1-03 1-0 •98 19-2 Wliito vood, lime tree. Original weight. 170° after 6 hours. Part 140°, and part 212° after 15 hours. After 2-1 hours. After 84 hours. After 84 hour.s.* Per cent. 1 2 3 4 23-5 25-19 23^67 20-08 20-45 21-33 19-7 17-07 18^7 19-37 17-83 15-8 18-22 18-9 * 17-6 15-6 17^4 18^07 16-82 15-13 17-4 18^0 16^75 15-05 20- 28-5 29-2 26^ No. 3 exposed to the atmosphere for three weeks, weighed at the end of that time 17^8, or had taken in 4-2 per. cent of moisture. * It will be observed, on referring to the last column of lime, that the wood, altliongli kept in the chamber exposed to heated currents for 50 hours, weighed notliing less after the tirst 34 hours. — ( W/i /'.■<- haw.) One application of the de.sicealing process fortiinber is to expose it for .some hours to the heated currents of air, and then, in its licated state, immersing it suddenly in any of the approved antiseptics, creosote or coal-tar. Tlio result is, that the air-ve.ssels of the wood, if not entirely empty, contain air at so very high a temperature that a vaeiuiin is instantly formed, and every poro is iinmodlatuly charged with the cold antiseptic in which tlio wood is immersed. 444 DEXTRINE. Feathers. — Feather beds, mattresses, blankets, and clothing are not only dried, but purified by this process. A feather bed of sixty pounds' weight, will have no less than 100,000 cubic feet of air passed through it ; and at the same time beaters are made use of, for the purpose of removing the dust. Feathers treated in this manner have their bulk and elasticity so much increased, that a second tick is found almost invariably necessary to put the feathers into. A practical proof of the extreme powers of currents of dry heated air was given in Syria, by exposing to them sixty suits of clothes, which had belonged to persons who died of the plague. These clothes were subjected to the process alluded to, at a temperature of about 240°, and afterwards worn by sixty living persons, not one of whom ever gave the slightest symptoms of being in the slightest degree affected by the malady. ( Whishaw.) The purification of feathers by tliis process is carried out in many large establishments. Coffee it has been proposed to dry by currents of heated air, and subsequently to roast it by the same process. 2' flick card-board, used for tea-trays and papier mache, is now frequently dried by heated air. By the plan adopted at one establishment, previously to the introduction of Davison and Symington's method, it invariably occupied from eighteen to twenty hours to dry a room full of paper by a heating surface equal to 330 feet ; whereas by the new method the same amount of work is accomplished in four hours, and with a heating surface of only 46 feet, or one-seventh the area required by the former. Silk. — For the purpose of drying silk, it has been usual to heat the drying chambers by large cast-iron globular stoves; the heat obtained thus was equal to 120° F., but excessively distressing to any stranger entering these apartments. In one arrangement 7,000 cubic feet per minute are admitted at the above tempera- ture through small perforated iron plates, let into the stone floor. As many as 3,000 pieces of silk are sometimes suspended at one time ; and as each piece of silk, when wet, contains about seven ounces of water, and as the operation of drying the whole occupies but one hour, it follows that about 130 gallons of water are evaporated in that time. Yarn/!. — In Scotland and other places they now dry yarns l)y modified applications of this process ; and it is indeed extensively used in lileaching establisliments, in calico-print- ing works, &c. See Trajisactions of the Society of Arts for 1847-'8. DEXTRINE. Starch Gum. There are three modes of obtaining this from starch, viz. : by torrefaction, by the action of dilute acids, and by the action of diastase. The impure dextrine obtained by roasting is termed roasted starch, or leicommc. British gum is pre- pared by carefully roasting wheat starch, at a temperature of 300° Fahr. Another method of preparing dextrine consists in moistening 1,000 parts of potato starch with 300 parts of water, to which two parts of nitric acid have been added. The mixture is allowed to dry spontaneously, and is afterwards heated for two or three hours in a stove at 212° Fahr. Dextrine in many of its characters resembles ordinary gum, but it is distinguishable from it bv its riqht-handcd rotation of a ray of plane polarized liyht, — hence its name dextrine, — and liy its yielding oxalic acid, but not mucic acid, when heated with nitric acid. Its chem- ical formula is C'-II»03,II0. DIA.MA(!XETISM. As this term is becoming more generally used in our language, it appears necessary to give a definition of it, although it is not our purpose to enter on the consideration of any purely physical subject. The term was introduced by Dr. Faraday to express those bodies which did not act as magnetic bodies do. If n and s represent the poles of a horse-shoe 215 magnet, any bar of a magnetic character, as iron, cobalt, or nickel, ;;c hung up between them and free to move, will, by virtue of the attract- ; \ ing and repelling polar forces, place itself along the line joining the NO ^ ' ' 1 cs two poles « b, which is called the magnetic axis. If instead of a bar I i of iron we suspend in the same manner a rod of glass, of bismuth, or [i^ of silver, it will arrange itself equatorially, or across the line a b, as shown by the dotted line c d. AH bodies in nature appear to exist in one of those two conditions. The prefix dia is used here in the same sense as in dia-meter. See De La Hire's Electricity, fou a full explanation of all the dianiagnetic phenomena. DIAMOND. {Diamant, Fr. ; I)ia7nant, Germ.) Experiment has determined that this beautiful gem is a peculiar (allotropic) condition of carbon. By burning the diamond in oxygen gas we produce carbonic acid ; and by enclosing the gem in a mass of iron, and suljecting it to a strong heat, the metal is converted into steel, when the diamond has dis- appeared. It has been shown tliat we can, by the agency of the heat of the voltaic arc, convert tlie diamond into excellent coke, and into graphite; but although portions of coke arc found to be sufficiently hard to cut glass, we have not yet succeeded in making dia- monds from coke. Sir Humphry Davy noticed that the charcoal of one of the poles of Mr. Children's great voltaic battery was considerably hardened, and he regarded this as an DIAMOND. 445 advance towards the production of that gem. Recently some experiments made by a French philosopher have advanced the discovery another step : one of the poles of a voltaic battery being charcoal and the other of platinum, it was found that the tine charcoal escaping from the carbon pole and depositing itself on the platinum pole was sufficiently hard to be used in the place of diamond dust for polishing gems. The formation of the diamond in nature is one of the problems which "our philosophy" has not yet enabled us to solve. Time is an element which enters largely into nature's works ; she occupies a thousand, or even thousands of years, to produce a result, while man in his experiments is confined to a few days, or a few years at most. The following remarks by Mr. Tennant cannot fail to be of interest, and, as pointing out the errors which have been frequently committed through ignorance, of great value. " By attending to the forms of the crystal, we are quite sure that we shall not find the emerald, sapphire, zircon, or topaz, in the form of a cube, octahedron, tetrahedron, or rhombic dodecahedron ; nor the diamond, spinel, or garnet, in that of a six-sided prism, and so on with other gems. For want of a knowledge of the crystalline form of the dia- mond, a gentleman in Caliibrnia offered £200 for a small specimen of quartz. He knew nothing of the substance, except that it was a bright shining mineral, excessively hard, not to be scratched by the file, and which would scratch glass. Presuming that these qualities belonged only to the diamond, he conceived that he was offering a fair price for the gem ; but the owner declined the offer. Had he known that the diamond was never found as a six-sided prism, terminated at each end by a six-sided pyramid, he would have been able to detect the fact that what he was offered £200 for, was really not worth more than half a crown." — Tennant's Lecture on Gems. The accompanying forms may serve to guide those who are ignorant of crystallography. 218 Brilliant, (upper side.) 219 Eose. Quartz. 100 carets. o er minute. The diamond is fixed in a ball of pewter at the end of an arm, resting upon the talile in which the plate revolves; the other end, at which the ball con- taining the diamond is fixed, is pressed upon the wheel by movable weights at the discretion of the workmen. The weight applied varies from 2 to 30 lbs., according to the size of tlie facets intended to be cut. The rccutting of the Koh-i-noor was commenced on July 10, 1852, His Grace the late Duke of Wellington being the first person to place it on the mill. The portion first worked upon w;u} that at which the planes p and F meet, as it was ncccs- DIPPING. 447 sary to reduce the stone at that part, and so to level the set of the stone before the table could be formed ; the intention being to turn the stone rather on one side, and take the incision or flaw at r., axid a fracture on the other side of the stone, not shown in the engrav- ing, as the boundaries or sides of the girdle. Tlie next important step was the attempt to •j.-2 > remove an incision or flaw at C, described by Professor Tennant and the Kev. W. Mitchell as having been made for the purpose of hold- ing the stone more firmly in its setting, but jironounccd by the cutters (after having cut into and examined it) to be a natural flaw of a yellow tinge, a defect often met with in small stones. The next step was cutting a facet on tlie top of the stone immediately above the last-mentioned flaw. Here the difl'erence in the hardness of the stone first manifested itself; for while cutting this facet, the hspidary notic- ing that the work did not proceed so fast as hitherto, allowed the diamond to remain on the mill rather longer than usual, without taking it off to cool ; the consequence was, tliat the diamond became so hot from the continual friction and greater weight applied, that it melted the pewter in which it was imbedded. Again, while cutting the same facet, the mill became so hot from the extreme hardness of the stone, that particles of iron mixed with diamond powder and oil ignited. The probable cause of the diamond proving so hard at this part is, that the lapidary was obliged to cut directly upon tlie angle at which two cleav- age planes meet, cutting across the grain of the stone. Another step that was thus consid- ered to be important by the cutters, was removing a flaw at g. This flaw was not thought by Professor Tennant and Mr. Mitchell to be dangerous, because if it were allowed to run according to the cleavage, it would only take olF a small piece, which it was necessary to remove in order to acquire the present shape. The cutters, however, had an idea that it might not take the desired direction, and, therefore, began to cut into it from both sides, and afterwards directly upon it, and thus they succeeded in getting rid of it. While cut- ting, the stone appeared to become harder and harder the further it was cut into, especially just above the flaw at a, v.'hich part became so hard, that, after working the mill at the medium rate of 2,4(10 times per minute, for six hours, little impression had been made ; the speed was therefore increased to more than 3,000, at which rate the work gradually proceeded. When the back (or former top) of the stone was cut, it proved to be much softer, so that a facet was made in three hours, which would have occupied more than a day, if the hardness had been equal to that on the other side ; nevertheless, the stone afterwards became gradu- ally harder, especially underneath the flaw at a, which part was nearly as hard as that directly above it. The flaw at n did not interfere at all with the cutting. An attempt was made to cut out the flaw at a, but it was found not desirable on account of its length. The diamond was finished on September Tth, having taken thirty-eight days to cut, working twelve hours per day without cessation." The weight of the Koh-i-noor since cutting is 102^ carats. DIAMOND TOOLS. 1. The Glazier's Diamond is the natural diamond, so set that one of its edges is brought to bear on the glass. The extreme point of any diamond will scratch glass, making a white streak ; but when tlie rounded edge of a diamond is slid over a sheet of glass with but slight pressure, it pro- duces a cut, which is scarcely visible, but which readily extends through the mass. Dr. Wollaston succeeded in giving to the ruliy, topaz, and rock crystal, forms similar to those of the diamond, and with those he succeeded in cuit.inr/ glass ; proving that tliis use- ful property of the diamond depended on its form. Although the primitive form of the diamond is that of a regular octahedron, the Duke de Bournon has published upwards of one hundred forms of crystallization of the diamond. The irregular octahedrons with round facets are those proper for glaziers' diamonds. Notwithstanding the hardness of the diamond, j-et, in large glass works, as many as one and two dozens are worn out every week : from being convex, they become rapidly con- cave, and the cutting power is lost. 2. Diamond Brills are made of various shapes ; these are either found amongst imper- fect diamonds, or are selected from fragments split off from good stones in their manufac- ture for jewelling. • DIES, hardening of. See Steet,, hardening of, vol. ii. DIPPIX(}. Ornamental works in Ijrass are usually brightened by a process called dip- pinrj. After the work has been properly fitted together and the grease removed, either by the action of heat, or by boiling in a pearl ash lye, it is pickled in a bath of dilute aqua fortis. It is then scoured bright with sand and water, and being well washed is plunged into the dipping bath, which consists of pure nitrous acid, commonly known as dipping aquafortis, for an instant oidy, and is then well washed with cold and hot water to remove 448 DISINFECTANT. every trace of acid from the surface, after which the work is put into dry beech or box wood, sawdust, &c., well rubbed uutil it is quite dry, and then burnished and lackered with as little delay as possible. DISINFECTANT. A substance which removes the putrid or infected condition of bodies. It is well not to confound it with antiseptic, which applies to those bodies which prevent putrefaction. The word disinfectant has lately become somewhat uncertain in its moaning, on account of a word being used as its equivalent, viz., deodorizer. This latter means a substance which removes odors. In reality, however, there are no such substances known to us as a class. There are, of course, some substances which dcstroj' certain others having an odor, but in all cases the removal of the smell and the destruction or neutraliza- tion of the body must be simultaneous. There is, however, a large class of substances that destroy putrefaction, and the name disinfectant is therefore distinctly needed. The gases which rise from putrefying bodies are not all capable of being perceived by the senses in their ordinary condition ; but sometimes they are perceived. A disinfectant puts a stop to them and deodorizes simultaneously. If any substance were to remove the smell of these gases, it would remove the gases too, as they are inseparable from their property of affecting the nose. A deodorizer would therefore be, and is, a disinfectant of that gas the smell of which it removes. But it has been suggested that it may remove those gases which smell, and allow the most deleterious to pass, they having no smell. Whenever we find such a class of substances, it will be well to give them the name of deodorizers. There may be some truth in the hypothesis that metallic salts remove the sulphur, and by preventing the escape of sulphuretted hydrogen c.ause less odor, without complete disinfec- tion. But it appears that the decomposition is a prevention of putrefaction in proportion to the removal of that gas in cases where it is given out, and it is quite certain that me- tallic solutions have disinfecting properties. Any solution having the effect here supposed would at the least be a partial disinfectant, inasmuch as the decomposition would be so far put a stop to, as to prevent at least one obnoxious gas. How the others could remain un- acted on in this case it is difficult to comprehend. To prevent the foi-mation of one gas is to arrest decomposition or to alter the whole character of the change which is producing the gases. The most deleterious of emanations have no smell at all to the ordinary senses, and we can only judge of the evil by its results, or the fact that the substances capable of producing it are near, or by the analysis of the air. (See Sanitary Akraxgemknts.) The cases where sulphuretted hydrogen accompanies the offensive matter, are chiefly connected with faecal decomposition. This gas is a useful indication of the presence of other sub- stances. So far as is known, the destruction of the one causes the destruction of the other. But the presence of sulphuretted hydrogen is no proof of the presence of infectious mat- ter, nor is its absence a proof of the absence of infectious matter, it being only an occa- sional accompaniment. When the infectious matter and the odoriferous matter are one, as in the case, as far as we know, of putrid flesh, &c., then to deodorize is to disinfect. We can find then no line of duty to be performed by deodorizers, and no class of bodies that can bear the name, although there may be a few cases where the word may be found convenient. If, for example, we destroy one smell by superadding a greater, that might in one sense be a deodorizing. If we added an acid metallic salt, and removed the sulphu- retted hydrogen, letting loose those organic vapors which for a while accompany this act, we might, to those who were not very near, completely destroy smell, and still send a sub- stance into the air by no means wholesome ; but in such a case decomposition is stopped, at least for a while. The smelling stage is by no means the most dangerous, nor has the use of the word deodorize any relation to sanitary matters, except in the grossest sense ; it is desiralile that persons should look far beyond the mere indications furnished by the nose, and as in science we can find no deodorizers, so in practice we need not look for any in the sense usually given to the word. The word may be used for such substances as remove the odor and the putrefaction of the moment, but allow them to begin again. Even in this case deodorizers become temporary disinfectants, which character all removers of smell must more or less have. Antincpticx, or Colytic Arjcnts. Substances which prevent decomposition. The words coli/.sis and coh/tic come from KwXveo, to arrest, ^rslrain, cut short. This word was pro- posed by the writer to apply to cases such as are included under antiseptics, antiferments, and similar word.s. There was needed a word for the general idea. A colytic force mani- fests itself towards living persons in anjcsthetics, anodynes, and narcotics, as well, probably, as in other ways. Colytics may probably act from diflcrcnt causes, but these causes not being separately distinguished, a name for the whole class can alone be given. The actioti of coll/sin is entirely opposed to catalysis, which is a loosening up of a compound. Colysis arrests catalyxis, as well also as other processes of decomposition, ordinary oxidation for example. Disinfectants, in their character of restraining further decomposition, are in- cluded under colyticn. One of the most remarkable substances for arresting decomposition is krea.sotc. It has Ijcen used in some condition or mixture from the earliest times. The ancient oil of cedar has been called Avith good reason turpentine, which has strong disin- DISIKFECTANT. WJ fecting properties ; but the word has evidently been used in many senses, as there are many liquids to be obtained from cedar. It is used for the first liquid from the distillation of wood ; and Berzelius for that reason says that the Egyptians used the pyroligneous acid, which, containing some kreasote, was a great antiseptic. But a mixture of this acid with soda would be of little value in embalming, nor is it probable that they would add a vola- tile liquid like turpentine along with caustic soda. It is expressly said (in Pliny) that the pitch was reboiled, or, in other word.-^, the tar was boiled and distilled, the product being collected in the wool of fleeces, from which again it was removed by pressure. In doing this the light oils or naphtha would be evaporated, and the heavy oil of tar, containing the carbolic acid, or kreasote, would remain. It was called picenum, as if made of pitch or pissenum, and pisselajum or pitch oil, a more appropriate name than that of Runge's car- bolic acid or coal-oil, and still more appropriate than the most recent, which, by following up a theory, has converted it into phenic acid. The distillation was made in copper vessels, and must have been carried very far, as they obtained "a reddish pitch, very clammy, and much fatter than other pitch." This was the anthracene, chryscne, and pyrcne of modern chemistry. The remaining hard pitch was called paliinpissa, or second pitch, which we call pitch in contradistinction to tar. By the second pitch, however, was sometimes meant the product of distillation instead of what was left in the still. Some confusion therefore exists in the names, but not more than with us. The pitch oil was resinous fat, and of yellow color, according to some. This oil, containing kreasote, was used for toothache — a colytic action applied to living bodies — and for skin diseases of cattle, for which it is found valuable. They also used it for preserving hams. — {^'' Dishifectants" by t/ie Writer. Jour. Soc. of Arts, 1857.) It is quite possible that kreasote may be the chief agent in most empyreumatic sub- stances which act as antiseptics. But it is not the only agent. Hydrocarbons of various kinds act as antiseptics, as well as alcohol and methylic alcohol, which contain little oxygen. To this class belong essential oils and substances termed perfumes which are used for fumiga- tion, and have also a powerful colytic action. It is exceedingly probable that the true the- ory of this action is connected with the want of oxygen. These substances do not rapidly oxidize, but, on the contrary, only very slowly, and that chiefly by the aid of other bodies. Their atoms are, therefore, in a state of tension, ready to unite when assisted. As an ex- ample, carbolic acid and kreasote unite with oxygen when a base is present, and form rosolic acid. We can scarcely suppose that an explanation, commonly resorted to in the case of sulphurous acid, would suit them ; viz., that it takes up the oxygen, and so keeps it from the putrescible substance. It is, therefore, much more likely that its condition acts on the putrescible body. For, as the state of motion of a putrefying substance is trans- ferred to another, so is the state of immobility. An antiseptic preserves from putrefaction, but does not necessarily remove the odor caused by that which has previously putrefied. Many of the substances described as disin- fectants here, might equally be called antiseptics. When they remove the putrid matter, they are disinfectants ; when they prevent decomposition, they are antiseptics. But when the smell is removed by a substance which is known to destroy putrefactive decomposition, and to preserve organic matter entire, then we have the most thorough disinfection ; then we know that the removal of the smell is merely an indication of the removal of the evil. Disinfectants are of various kinds. Nature seems to use soil as one of the most active. All the dejecta of tlie animals on the surface of the earth fall on the soil, and are rapidly made perfectly innoxious. Absorption distinguishes porous bodies, and the soil has peculiar facilities for the purpose. But if saturated, it could disinfect no longer. This is not allowed to occur ; the soil absorbs air also, and oxidizes the organic matter which it has received into its pores, and the offensive matter is by this means either converted into food for plant;;, or is made an innocent ingredient of the air, or, if the weather be moist, of the water. The air is therefore, in conjunction with the soil, one of the greatest disinfectants, but it acts also quite alone and independent of the soil. Its power of oxidizing must be very great. The amount of organic effluvium sent into large towns is remarkal)le, and yet it seldom accumulates so as to be strongly perceptible to the senses. The air oxidizes it almost as rapidly as it rises ; this is hastened apparently by the peculiar agent in the air, ozone, wliich luis a greater capacity of oxidation than the common air ; when this is exhausted it is liighly probable that the oxidation will be much slower, and this exhaustion does take place in a very short time. So rapid is the oxidation, that the wind, even lilowing at the rate of about fifteen to twenty miles an hour, is entirely deprived of its ozone l)y passing over less than a mile of Manchester. In London tins does not take place s^ rapidly, at least near the Thames. But when the ozone is removed, it is prol)al)le that the rate of increase of tlie organic matter will be much greater. We nuiy by this means, then, readily gauge the con- dition of a town up to a certain point by the removal of the ozone : but it rccjuires another agent to gauge it afterwards or thoroughly. It is in connection with each other that the air and the soil best disinfect. When manure is thrown upon land without mixing with the soil, it may require a very long period to obtain thorough disinfection, but when the atmos- VoL. III.— 29 450 DISINFECTANT. phere is moist, or rain falls, then the air is rapidly transferred into every portion of the porous earth, and the organic matter becomes rapidly oxidized. To prevent a smell of ma- nure, and with it also the loss of ammonia, it is then needful that as soon as possible the manure should be mixed with the soil. The same power of oxidation is common to all porous bodies, to charcoal, and especially, as Dr. Stenhouse has shown, to platinized char- coal. Disinfection by the use of porous bodies is not a process of preservation, liut of slow destruction. It is an oxidation in which all the escaping gases are so thoroughly oxi- dized, that none of them have any smell or any oflensive property. But being so, the body disinfected must necessarily decay, and in reality the process of decay is remarkably in- creased. All such bodies must therefore be avoided when manures are to be disinfected, as the valuable ingredients are destroyed instead of being preserved. Stenhouse has enipl()\ ed charcoal for disinfecting the air. The air is passed through the charcoal either on a large scale for a hospital, or on a small scale as a respirator for the mouth. Care must be taken, however, to keep the charcoal dry : wet charcoal is not capable of absorbing air until that air is dissolved in the water. This solution takes place less rapidly in water. Wet charcoal is therefore a filter for fluids chiefly, and dry charcoal for vapors. Its destructive action on manures will, however, always prevent charcoal from being much used as a disinfectant for such purposes, or, indeed, any other suljstance which acts principally by its porosity or by oxidation. This the soil does only partially, as it has another power, viz., that of retaining organic substances fit to l)e the food of plants. Although air acts partly in conjunction with the soil and the rain to cause disinfection, and partly by its own power, it also acts mechani- cally as a means of removing all noxious vapors. The wind and other currents of the air are continually ventilating the ground, and when these movements are not sufficiently rapid, or when they are interrupted by our mode of building, we are compelled to cause them artificially, and thus we arrive at the art of ventilation. The addition of one-tenth of a per cent, of carbonic acid to the air may be perceived, at least if accompanied with the amount of organic matter usually given out at the same time in the breath ; and as we exhale in a day 20 cubic feet of carbonic acid, w-e can injure the quality of 20,000 cubic feet of air in that time. The great value of a constant change of air is therefore readily proved, and tl;e instinctive love which we have of fresh air is a sufficient corroboration. Cold is a great natural disinfectant. The flesh of animals may be preserved, as far as we know, for thousands of years in ice ; putrefying emanations are completely arrested by freezing, but the mobility of the particles, or chemical action, is also retarded by a degree of cold much less than freezing. Heat is also a disinfectant, when it rises to about 140° of Fahrenheit, according to Dr. Ilcnry. But as a means of producing dryness it is a disinfectant at various temperatures. Nothing which is perfectly dry can undergo putrefaction. On the other hand, heat with moisture below 140° is a condition very highly productive of decomposition and all its resulting evils. Disinfection by heat is used at quarantine stations. Light is undoubtedly a great disinfectant ; so far as we know, it acts by hastening chemical decomposition. In all cases of ventilation, it is essential to allow the rays of light to enter with the currents of air. Its effect on the vitality of the human being is abundantly proved, and is continu- ally asserting itself in vegetation. The true disinfecting property of light exists in all jirobability in the chemical rays which cause compositions and decompositions. Water, iiowever, is of all natural disinfectants the most manageable, and there is no one capable of taking its place actively. Wherever animals, even human beings, live, there are emanations of organic matter, even from the purest. The whole surface of the house, furniture, floor, and walls, becomes coated by degrees with a thin covering, and this gradually decomposes, and gives off unpleasant vapors. Sometimes it becomes planted with fungi, and so feeds plants of this kind. But long before this occurs a small amount of vapor is given off suffi- ciently disagreeable to affi:?ct the senses, and sometimes afl'ecting the spirits and the health before the senses distinctly perceive it. This must be removed. In most cases this film is removed hj water, and we have the ordinary result of household cleanliness ; but in other cases, when the furniture is such as will be injured by water, tlic removal is made by fric- tion, or by oil or turpentine, and other sutistances used to polish. Water as a disinfectant is used also in washing of clothes ; for this purpose nothing whatever can supply its place, a'thougli it requires the assistance both of soap and friction, or agitation and heat. Water is also used as a mechanical agent for removing filth, and the method which Hercules de- vised of using a river to wash away filth, is now adopted in all the most advanced plans of cleansing towns. It is only by means of water that the refuse of towns can be conveyed away in covered and impeijirious passages, whilst none whatever is allowed to remain in the town itself. In cases where this cannot be done, it is much to be desired that some disin- fecting agent should be used to prevent decomposition. Where water is not used, as in water-closets, there must of course be a great amount of matter stored up in middens, and the town is of course continually exposed to the effluvia. Besides these methods of acting, water disinfects partly by preventing effluvia from arising from bodies, simply because it keeps them in solution. This action is not a perfect one, but one of great value. The DISINFECTANT. 451 water gives off the impurity slowly, sometimes so slowly as to be of no injury, or it keeps it so long that complete oxidation takes place. The oxygen for this purpose is supplied by the air, which the water absorbs without ceasing. To act in this way, water must be delivered in abundance ; when only existing as a moisture, water may act as a great oppo- nent to disinfection by rising up iu vapor loaded with tlie products of decomposition. Mere drying is known to arrest decay, as the mobility of the particles in decomposition is stayed by the want of water. We are told in Anderssen's Travels iu South Africa, that the Damaras cut their meat into strips, and dry it in the sun, by which means it is preserved fresh. A similar custom is found in South America. Certain days prevent this, and de- composition sets in rapidly. A little overclouding of the sky, or a little more moisture in the air, quickly stops the process. The above may be called natural disinfectants, or imitations of natural processes, char- coal being introduced as an example of a more decided character of porous action. They show both mechanical and chemical action. The mechanical, when water or air removes, dilutes, or covers the septic bodies : the chemical, when porous bodies act as conveyers of oxygen : or an union of both, when cold and heat prevent the mobility of the particles. The action by oxidation causes a destruction of the offensive material. The other method is antiseptic. It is much to be desired that all impurities should be got rid of by some of these methods, but especially by the air, the water, and the soil. There are, however, con- ditions in which difficulties interfere with the action. Large towns may be purified by water, but wiiat is to be done with the water which contains all the impurity ? If put upon land, it is very soon disinfected, but on its way to the land it may do much mischief. It has been proposed to disinfect it on its passage, and even in the sewers themselves ; by this means the town itself is freed from the nuisance, and the water may be used where it is needed without fear. This introduces artificial disinfectants. There are other cases where such are required — when the refuse matter of a town is allowed to lie either in exposed or in underground receptacles ; in this case a town is exposed to an immense surface of im- purity, and disinfectants would greatly diminish the evil, if not entirely remove it. There are, besides, special cases without end continually occurring, where impurities cannot be at once removed, and where treatment with artificial disinfectants is required. Artificial disinfectants which destroy the compound, are of various kinds. J^re is one of the most powerful. A putrid body, when heated so as to be deprived of all volatile par- ticles, cannot any longer decompose. It is however possible that the vapors may become putrid, and if not carefully treated, this will happen. It was the custom of some of the wealthy among the ancients to burn the dead, and it is still the custom in India ; Ijut although the form is kept up amongst all classes, the expense is too great for the poor. The bodies are singed, or even less touched by fire, and thrown if possible into the river. This process has been recommended here, but the quality of the gaseous matter rising from a dead body, is most disgusting to our phvsical, and still more to our moral senses, and the amount is enormous. It is of course possible so to burn it, that only pure carbonic acid, water, and nitrogen, shall escape ; but the probability of preventing all escape is small enough to be deemed an impossibility, and the escape of one per cent, would cause a rising of the whole neighborhood. To effect the combustion of the dead of a great city, such a large work, furnished with great and powerful furnaces, would be required, that it would add one of the most frightful blots to modern civilization, instead of the calm and peaceful churchyard, where our bones are preserved as long at least as those who care for us live, and then gradually return to the earth. In burning the dead, some prefer to burn the whole body to pure ash. This was the ancient method ; but it is highly probable that the ashes which they obtained were a delusion in most cases. The amount of ash found in the urns is often extremely small. The body cannot be reduced to an infinitesimal ash, as is sup- posed ; eight to twelve pounds of matter remain from an average man when all is over. A second plan, is to drive off all volatile matter, and leave a cinder. This disgusting plan leaves the body black and incorruptible. It can never, in any time known to us, mix with its mother earth, and yet ceases at once to resemljle humanity in the slightest degree ; it will not even for a long time assist us by adding its composition to the fertility of the soil. The burning of bodies never could have been general, and never can be general, l^'we has only a limited use as a disinfectant. It cannot be used in the daily disinfection of the dejecta of animals, and is applied only occ;isionally, where the most ra])id destruction is the most desirable, either because the substance has no value, or it is too disgusting to exist, or the products afti'r burning arc not offensive. There are two methods of using fire, char- ring or burning to ashes. The second is an act of Oxidation. — This is effected either by rapid combustion called fire ; by slow combus- tion, the natural action of the air ; or by chemical agency, sometimes assisted by mechani- cal. Slow oxidation in the soil is a process which is desirable in every respect, and it would be well if we could bring all offensive matter into this con41 As to the modus operandi : — The operator with his assistants enters the machine through the top, which is then closed. To descend, the water-cock b is opened, and the external water flows into the chambers w w ; at the same time a cock, on a pipe opening from the chambers outwards, is opened, in order that, the air escaping, an uninterrupted flow of water may take place into the chambers. The weight of water entering the chambers causes a destruction of the buoj'ancy of the machine, and the nautilus gradually sinks. As soon as it is fairly under water, in order that the descent may be quiet and without shock, the water-cock b is closed. The receiver at the surface being previously charged by the air- pump to a density somewhat greater than that of the water at the depth proposed to attain, one of the l)ranch cocks on tlie i)iiie <■ <; connecting the chambers at top, is opened, and the air rushes into the working chaml)er, gradually condensing until a density equal to the den- sity of the water without is attained ; this is indicated by proper air and water gauges. DIVING BELL. 469 These gauges marking equal points, showing the equilibrium of forces without and within, the cover to the bottom z is removed or raised, and commuuicatiou is made with the under- water surface, on which the nautilus is resting. In order to move about iu localities where tides or currents do not affect operations, it is only necessary for the workmau to step out of the bottom of the nautilus, and placing the hands against its sides, the operator may move it (by pushing) in any direction. Where currents or tides, however, have sway, it becomes necessary to depend upon fixed points from which movements may be made in any direction. Tliis is accomplished by placing, in the bottom of the nautilus, stuffing-boxes of peculiar construction, (m m, fiy. 242,) through which cables may pass over pulleys to the external sides, thence up through tubes, (to prevent their being worn,) to and over oscillating or swinging pulleys, placed in the plane of the centre of gravity of the nautilus, and thence to the points of affixmcnt respectively, {fig. 243.) The object to be gained by having the swinging pulleys in the plane of the centre of gravity of tlie mass, is to hold the machine steady and to prevent oscillation. Within the maciiine, and directly over the above stuffing-boxes, are windlasses for winding in the cables. By working these windlasses movement may be effected, and of course the number of these cables will depend on the variable character of the situation to be occupied. Having thus secured the means of descending, communicating with the bot- tom, and of movement, the next point is to ascend. Weight of water has caused a destruc- tion of buoyancy at first, and consequent sinking ; if, then, any portion of this water is removed, an upward effort will at once be exerted exactly proportionate to the weight of water thrown off. The air in the receiver at the surface being constantly maintained at a higher density than that of the water below, if we open the water-cock on the top pipe c c, throwing the condensed air from the receiver above directly on to the surf^ace of the water in the chambers, movement and consequent expulsion of the water must take place, and an upward movement of the machine itself, which will rise to the surface. It is evident that if, previously to the expulsion of the water, the nautilus be affixed to any object below, the power exerted on that object will be exactly proportionate to tlie weight of water expelled, and the power will continue increasing, until, there being no f\ir- ther weight to be thrown off, the maximum effect is produced. To apply this power to lift- ing masses of stone or rock, proper arrangements are affixed to tlie centre of the opening in the bottom, by which connection can be made with tlie weight, admitting, at the same time, the swinging around of the oliject suspended, so that it may be placed in any required position. In the construction of permanent work, or the movement of objects whose weight is known, or can be estimated, a water, or so-called lifting tube, is placed on the side of the water chamber, which indicates the lifting power exercised by the nautilus at any mo- ment. The advantage of tliis gauge will be recognized, inasmuch as without it the closest attention of the operator, working very cautiously, woukl be necessary to determine when the weight was overcome ; by its aid, however, the operator boldly throws open all the v, lives necessary to develop the power of the nautilus, watching only the gauge. The water, having reached the proi)cr level indicating the required lifting power, he knows the weight must be overcome, or so nearly so that the valve or cocks may be at once closed, in order that the movement may take place horizontally. A moment's reflection will show that, if 470 DIVING BELL. there were not an index of this character, carelessness or inattention on the part of the operator, by leaving the cocks open too long, might develop a power greater than required, and the nautilus would start suddenly upward. The expansive power of air, acting upon the incompressible fluid, water, through the opening in the bottom, gives a momentum which, by successive developments of expansion in the working chamber, is constantly increasing in velocity, until, in any considerable depth of water, the result would be un- doubtedly of a very serious character. Take, for exemplification, the nautilus in thirty- three feet of water, and bottom covers removed, and an equilibrium, at fifteen pounds to the inch, existing between the air and the water at the level of the bottom of the machine. Upward movement is communicated the instant the machine rises in the slightest degree, the existing equilibrium is destroyed, and the highly elastic qualities of air assume prepon- derance, exerting, from the rigid surface of the water below, an impulsive effort upward in the direction of least resistance. At each successive moment of upward movement the impelling power increases, owing to the increasing disparity between the pressure of air within struggling for escape. Tlie machine, thus situated, becomes a marine rocket, (in reality,) in which the propelling power is exhausted only when the surface is reached, and a new equilibrium is obtained. It will readily be seen that, were this difficulty not overcome, it would be impossible to govern the nautilus; for, rising with great velocity to the surface, the machine is carried above its ordinary flotation, or water line, a little more air escaping owing to the diminished resistance as that level is passed ; the recoil, or surging downwards, causes a condensation of the air remaining in the chamber ; a portion of the space pre- viously occupied by air is assumed by water ; the buoyant power becomes less, the machine settles slightly more by condensation of the air, a larger space is occupied by water, and the nautilus redescends to the bottom with a constantly accelerating movement, seriously inconveniencing the operator by filling more or less with water, according to depth. For many months the difficulties just enumerated baffled all attempts at control. A weight attached could be lifted, but the instant it was entirely suspended, — before the valves could b(! closed, — upward movement was communicated beyond control. This difficulty, so fatal, li:is been overcome by an arrangement at the bottom of the nautilus, with channels which radiate from the opening in an inclined direction, debouching at the sides of the machine. T'.ie moment, then, that the air, by its expansion from diminished resistance, or by the iiitroduction from above of a greater volume than can be sustained by the water below, reaches, in its do^^^lward passage, the level of these chambers, following the direction of 244 DIVING BELL. 471 least resistance, it passes througli these channels and escapes into the surrounding Tcatcr, without of course aftecting the movement of the machine in the least. The pump for supplying air to the diving-bell or other suitable vessel, is represented at figs. 244 and 245, and is constructed as follows : — d is a cylinder, opening at the upper part into a chamber or chambers f f, separated by a partition e. On the side of each of these chambers there is a valve h h, opening inwards, and at the upper part of the same are two valves i i, opening outwards into the valve chamber g. Outside the opening for each of the valves ii u, there is a cup, into which the end of the water supply pipe m passes ; by this means a small stream of water is supplied to the cup, and is drawn frc^n it into the chamber f to supply the waste in the operation of pumping. The valve chamber g is cov- ered with a jacket k, having a space between it and the valve chamber that is filled with water from the water pipe m, which affords a stream of cold water to carry off the heat from the condensed air which is forced into the chamber. The water thus supplied circulates through the tubes in the chamber and round them in the jacket, and thus cools the air in these tubes ; it is then conveyed so as to be usefully employed in a steam-boiler, or is allowed to run off. The air and a small quantity of water is forced up from the cylinder d by the stroke of the piston c into the chamber f, which is thereby filled with water, and thus the air is expelled therefrom, a small quantity of the water passing with it and cover- ing the valves, by which means they are kept tight and wet. The air and water thus dis- charged, after passing around the small tubes in the valve chamber and being cooled, are forced outward and conveyed to the condenser. On the return stroke of the piston, the other chamber f is filled, and air and water expelled from it in like manner through its valve into the valve chamber. There is always a sufficient quantity of water in the cylin- der D and chamber f to fill the latter when the water is all expelled from the cylinder, by the piston c having been driven to one end of it, and when the piston returns to the oppo- site end of the cylinder, the water flows in b'ehind it, and draws in its equivalent in bulk of air and water through the valve h. On its return, this is forced out through the valve k into the chamber i, as mentioned above. The water being non-elastic, if the parts are kept cool enough to avoid raising steam, this process may be continued for any length of time. A transverse section of this apparatus is shown in fig. 245. Figs. 240 and 247 represent the speaking-tube and alarm-bell above referred to. The construction of this mechanism is as follows: — There is a hollow casting, one portion of which is triangular in form, from one end of which a short tube a projects. This tube a has a screw cut on it, and a projecting flange at its junction with the triangle. This is screwed into the top of the diving vessel or armor from the inside, and projects through 472 DIVIXG BELL. it to allow the coupling of a flexible or other hose to be attached to it. At the opposite angle, and in a line with a, there is a tubular projection h, provided with a screw to receive a cap /, to which is to be attached a piece of hose. Within the tube /, and at its junction witii 6, is placed a thin diaphragm of metal or other suitable material c, for which purpose, however, a thin silver plate that just fits the bore of the cap /" is preferred. This diaphragm closes all communication between the diving vessel and the external air. By this means ii is easy to converse through any required length of tuljing. It may be desirable to fit a stop-cock into the tubular projection b, as a precautionary means of preventing the escape of air in the»event of a rupture of the diaphragm. The upper part of the triangular en- largement of the speaking-tube is tapped for a stuffing-box at a, within which tliere is an axis /?, which runs from side to side of the said enlargement, and through tl;e stiiHing-box at one side. On this axis // is fixed a lever i within the said enlargement, which lever com- municates with the surface of the water by means of a wire fixed at its reversed end, and running through the whole length of pipe. On the outer extremity of the axis // is affixed a hammer, which strikes on a bell k connected to the tube, as shown in the drawing. By this means the attention of the operator below may be drawn to the speaking-tube when it is required to converse with him from the surface of the water, and the men whose duty it is to attend to the operator below can, by placing their ear at the end of the tube, hear the bell struck below as a signal for communication with them at the surface. The only parts of the apparatus not yet described, are the saw for cutting the tops of piles to an uniform level, the pump which enables the divers themselves to rise to the sur- face in the event of the flexible hose being detached or injured, and the contrivance for screwing an eye-bolt into the side of the sunken vessels. The arrangement of the saw-frame 24S and connections are shown in p'g. 248. Only as much of the bottom of the nau- tilus is shown as will render the position of the saw understood. p is a pile which is required to be cut down to the same level as the others ; e is the blade of the saw ; d the framing by which it is stretched ; c, n, the handle which rests on the cross-bar k ; to which is attached the upright part of the handle which is laid hold of by the workman inside when woiking the saw. h, g, f, a bent lever with two friction rollers at f winch guides the saw forwards while making the cut. The pump for ascending in case of accident to the air-hose, is not shown in the drawing. It is a simple force-pump placed in the working chamber, by which the ballast water in w w, (fie/. 242,) can be pumped out so as to lighten the ap- paratus sufficiently to allow of its ascent. The apparattts for fixing the eye-bolts is shown in _/%/. 249. The operation of this apparatus is as follows : — It will be observed the chamber d opens outwards to the water, so that when the sliding partition or valve ;/ is forced down by the lever eated. It will hence be ob- vious that a number of eye-bolts might in tliis manner be successfully inserted in the side of a sunken vessel from the diving-bell, so that by hooking on the " camels," the strain would be so distributed as to prevent injury by the process of lifting the said vessel. DOLO.MITE. Magnesian Limestone. This rock occurs in very great abundance in various parts of England, especially in Yorkshire, Nottinghamshire, and Somerset. It is largely employed as a building stone. Karsten infers, from his numerous analyses of dolomite, that in those which are crystal- lized, the carbonate of lime is always combined in simple equivalent proportion with an- other carbonate, which may be carbonate of magnesia alone, or together with carbonates of iron or manganese, and sometimes both. In the uncrystallized varieties of dolomite, the diversity in the proportion of lime and magnesia is indetinite, but such ma.^ses must be re- garded as mere mixtures of true dolomite and carbonate of lime. Acids do not produce a perceptible eftervescence with dolomite, except when digested whh it in fine powder. Karsten found that dilute acetic acid extracts from dolomites, at a temperature below 32' Fahr., only carbonate of lime, while a dolomitic mass remains undissolved. Hence he re- gards them as mixtures of dolomite with unaltered carboiuite of lime. — Bischof. Sulphate of magncaia has been manufactured from dolomite on the large scale. Dr. William Henry, of Manchester, patented a process of the following kind : — Calcine magnesian limestone so as to expel the carbonic acid ; then convert the caustic lime and magnesia into hydrates by moistening them with water ; afterwards add a sufficient quan- tity of hydrochloric, nitric, or acetic acid, or chlorine to dissolve the lime, but not the mag- nesia, which, after being washed, is converted into sulphate by sulphuric acid, or, where the cost is objectionable, by sulphate of iron, which is easily decomposed by magnesia. Or the mixed hydrates of lime and magnesia are to be added to bittern : chloride of calcium is formed in solution, while two portions of magnesia (one from the bittern, the other from the magnesian lime) are left unacted on. Hydrochloratc of ammonia may be used instead of bittern : by the reaction of this on the hydrated magnesian lime, chloride of calcium and caustic ammonia remain in solution, while magnesia is left undissolved ; the ammonia is separated from the decanted liquor by distillation. In some chemical works on the Tyne, the dolomites from the coast around Marsden are treated with sulphuric acid, and the sulphate of magnesia {Epwm salts) separated from the sulphate of lime by crystallization. The dolomite has also been employed by the late Hugh Lee Pattinson for the manufac- ture of the Carbonate of Magnesia. DOWN. See Feathers. Down imported in 1857, 5,208 lbs. DRAGON'S BLOOD. Pereira enumerate:^ he following varieties of this substance found in commerce : — 1. Dragon^s blood in the reed ; DragorCs blood in sticks ; Sanguis Draconis in baculis. 2. DragorCs blood in oval masses ; Dragon^s blood in drops ; Sanguis Draconis in lachrymis. 3. Dragon's blood in powder. 4. Dragon^ s blood in the tear ; Sanguis Draconis in granis. 5. Lrimp Dragon'' s blood ; Sanguis Draconis in massis. Besides these, there are Dragori's blood in cakes, and False Dragonh blood, in oval masses. DRAINING TILES. Burnt-clay tiles, generally shaped in section like a horse shoe, about one foot long and two or three inches broad. These are much used in agricultural draining. DRY GRINDING. The practice of employing dry stones has been long adojited for the purpose of quickening the processes of .sharpening and polishing steel goods. The dry dust from the sand-stone, mixed with the fine particles of steel, being inhaled by the workmen, produces diseases of the pulmonary organs to such an extent, that needle and fork grinders are reported rarely to live beyond the ages of twenty-five or thirty. Mr. Abraham, of Sheffield, first invented magnetic guards, which, being placed close to the grindstone, attracted the particles of steel, and thus protected the men from their influ- ences. Still they suffered from the cfTccts of the fine sand-dust, and the grinders heedlessly abandoned the use of them altogether. Mr. Abraham devised another plan, which is employed, although only partially, in the 474 DULSE. Sheffield works. The grindstone is enclosed in a wooden case, which only exposes a por- tion of the edge of the stone ; a horizontal tube proceeds as a tangent from the upper sur- face of the circle to the external atmosphere. The current of air generated by the stone in rapid revolution, escaping through the tube, carries off with it nearly all the dust arising from the process. It is curious to find so simple a contrivance frequently rejected by the workmen, notwithstanding that sad experience teaches them, that they are thereby expos- ing themselves to the iufiuences of an atmosphere which produces slowly but surely their dissolution. DULSE. The Rhodomenia palmata. See Alce. DUNES. Low hills of blown sand, which arc seen on the coasts of Cheshire and Cornwall, in this country, and also in many places skirting the shores of Holland and Spain. DUTCH LEAF or FOIL, a composition of copper and lime, or of bronze and copjier leaf. See Alloys, Bkass, and Bronze Powdkks. DUTCU RUSH. Eipdsdum Hyemalc. This rush is known also as the Large hranch- less Horse-tail. The dried stems are much employed for polishing wood and metal. For this purpose they are generally imported from Holland. DYEING. The relations of dyeing with the principles of chemistry, constitute the theory of the art, properly speaking ; tlii^ theory has for its basis the knowledge — 1st. Of the nature and properties of the bodies which dyeing processes bring into contact. 2d. Of the circiunstances in which these bodies are brought together, faciUtating or re- tarding their action. 3d. The phenomena which appear during their action ; and 4th. Properties of the colored combinations which are produced. The fii-st of these generalities embraces a knowledge of the preparations which stuff ne- cessarily undergoes previous to dyeing, and also the preparations of the dye-drug before bringing it into contact with the stuff'. The operations to which stuffs are subjected before dyeing, are intended to separate from them any foreign matters which may have become attached, or are naturally inherent in the stuff. The former are such as have been added in the spinning, weaving, or other manipulations of the manufacture, and are all removed by steeping in an alkaline lye and washing. The second are the natural yellow coloring substances which coat some of the various fibres, both vegetable and animal ; and the chlorophylle, or Jeaf-green of vegetables. The removal of these is generally effected by boiling in soap and alkaline lyes. A weak bath of soda, in which the stuff is allowed to steep for some time, and then washed in water, is generally the only preparation required for wool, in order that it may take on a uniform dye. To remove the gummy or resinous matter from silk, it requires boiUng in soap lye ; however, its removal is not essential to the stuff combining with the dye, as silk is often dyed while the gum remains in it, in which case it is only rinsed in soap lye at a very mod- erate heat, to remove any foreign matters imbibed in the process of manufacture. Vegetable fibre, as cotton, has such natural resinous matters that retard the reception of the dye removed by boiling, either with or without alkaline lyes ; but the natural dun color of the fibre is not removed, which from the laws of light and color already referred to, would interfere with the production of bright light tints ; under these circumstances, the natural color of the fibre has to be previously removed by bleaching, for which see the ar- ticle, Bleaching. The necessary preparation of the dye-drugs within the province of the dyer, is to obtain the color in a state of solution, so as to allow the fibre to absorb it, and to produce chem- ical combination, or to get the dye or color in such a minute state of division as it will penetrate or enter into the filjre of the stuff. These preparations embrace the formation of decoctions, extracts, and solutions, and also in some cases of precipitation, previous to im- mersing the stuff" into the bath. Stuff's, chemically considered, have but a feeble attraction for other matters, so as to combine with them chemically ; still, that they do possess certain attractions is evident from various phenomena observed in the dyeing processes, and that this attraction is possessed with different degrees of intensity by the different fibres, is also evident from the ease and permanence that woollen stuff' will take up and retain dyes com- pared with cotton ; and also, that certain dj'cs are retained and fixed within or upon one kind of fibre and not at all in another. This may be determined by plunging the dry stuff into solutions of the salts, and determining the density of the solution before the immersion and after withdrawing the stuff. Wool abstracts alum from its solution, but it gives it all out again to boiling water. The sulphates of iron, copper, and zinc resemble alum in this respect. Silk steeped for some time in a solution of protosulphate of iron, abstracts the oxide, and gets thereby dyed, and leaves the solution acidulous. Cotton in nitrate of iron produces the same effect. Wool put in contact with cream of tartar, decomposes a portion of it ; it absorbs the acid within its pores, and leaves a neutral salt in solution in the liquor. DYEING. 475 Cotton produces no such effect with tartar, showing by these different effects that there are certain attractions between the stuff and dyes. This attraction, however, may be more what is termed a catalytic intiuence, the fibres of the stuff producing a chemical action with the salt or dye with which it is in contact. This attraction or affinity of the fibre for the dye- drug does not produce a very extensive effect in the processes of dyeing. More prob- ably the power of imbibing and retaining colors possessed by the fibre is more dependent upon a mechanical than a chemical influence. All dye-drugs must in the first instance be brought into a state of solution, in order that the dye may be imbibed by the fibre ; but if the fibre exerts no attraction for the color so as to retain it, it is evident that so long as it remains capable of dissolving in water, the stuffs being brought into contact with water will soon lose their color. A color thus formed does not constitute a dye, however strongly stained the stuH's may appear to be, in or out the dyeing solution ; in order to form a dye, the color must be fixed upon or within the stuff in a condition insoluble in water. Hence the mere immersion of the stuff into a solu- tion of a color will not constitute a dye, except where the stuff really has an attraction for the color and retains it, or causes a decomposition by which an insoluble compound is fixed upon it, such as referred to by putting stuffs into solutions of iron. The abstraction of the color from a solution by the immersion of the stuff, is often the result of a mechanical at- traction possessed by porous substances, enabling them to absorb or imbibe certain color- ing matters from solutions that are held by a weak attraction by their solvents. On this principle, a decoction of cochineal, logwood, brazil-wood, or a solution of sulphate of in- digo, by digestion with powdered bone black, lose their color, in consequence of the color- ing particles combining by a kind of capillary attraction with the porous carbon, without undergoing any change. Tlio same thing happens when well scoured wool is steeped in such colored liquids ; and the color which the wool assumes by its attraction for the dye is, with regard to most of the above colored solutions, but feeble and fugitive, since the dye may be again abstracted by copious washing with simple water, whose attractive force, therefore, overcomes that of the wool. The aid of a high temperature, indeed, is requisite for the abstraction of the color from the wool and the bone-black, probably by enlarging the size of the pores, and increasing the solvent power of the water. Those dyes, whoso coloring matter is of the nature of extractive, form a faster combi- nation with stuffs. Thus the yellow, fawn, and brown dyes, which contain tannin and ex- tractive, become oxygenated by contact of air, and insoluble in water ; by which means they can impart a durable dye. When wool is impregnated with decoctions of that kind, its pores get charged by capillarity, and when the liquid becomes oxygenated, they remain filled with a color now become insoluble in water. The fixation of iron oxide and several other bases also depends on the same change within the pores or fibre ; hence all salts that have a tendency to pass readily into the basic state are peculiarly adapted to act as a me- 'dium for fixing dyes ; however, this property is not essential. In order to impart to the stuffs tlic power of fixing the color in an insoluble form upon it, recourse is had to other substances, which will combine with the soluble and form with it an insoluble color ; and it is not necessary that this new substance should have an attrac- tion for the stuff, or be cajiable of passing into a basic form, any more than the original color, but it is necessary that it be rendered insoluble while in contact with the stuff. Such substances used to unite the color with the stuff have been termed mordants, which meant that they had a mutual attraction for the stuff and color, and combining with the st.uff first, they afterwards took up the color ; but this is only so in some instances. A few examples will illustrate the bearing of these mordants. If a piece of cotton stuff is put into a decoction of logwood, it will get stained of a depth according to the color of the solution, but this stain or color may be washed from the cotton by putting it into pure water, the color being soluble. If another piece of cotton stuff be put into a solution of protosulphate of iron, and then washed from this, a portion of the iron will have undergone oxidation, and left the acid, and become fixed upon the fibre and insoluble in water. Whether this oxidation is the result of an influence of the stuff, or the effect of the oxygen of the air and water in which the goods are exposed, it does not matter meantime, only this fixed oxide constitutes an example of a mordant by its combining with the stuif. If this stuff is now put into a decoction of logwood, the cohn-ing matter of the logwood will combine with the oxide of iron fixed upon the fibre^ and form an insoluble color, which after washing will not remove from the stuff. If, instead of washing the stuff from the sul- ])hate of iron solution in water, it be passed through an alkaline lye of soda or potash, the acid holding the iron in solution is taken hold of by the alkali, and removed. Tiie oxide of iron is thus left upon the stuff, in a much larger quantity than in the former case, and as firmly fixed, although not by any attraction between it and tlie fibre, l)ut simi)ly being left within it. And this stuff being now ])ut into the logwood liquor, will form a dye of a depth according to tlie ([uantity of iron thus fixed upon the stuff, and equally permanent with that which had been fixed on the stuff by the oxidation in working. 470 DYEING. Such, then, are the methods of fixing within the stuff insoluble colors from soluble eoinpounJs, and from these remarks the necessity of liaving the dye in solution will also be evident. Suppose, again, that the sulphate of iron be mixed with the logwood decoction, there will be produced the same color or dye as an insoluble precipitate : if the cotton stuff is put into this, no color worthy of the name of a dye will be obtained, as the cotton will not imbibe within its fibre this precipitate. Place woollen stuff in the same liquid, there is formed a very good dye, the woollen fil)re having mibibed a great portion of the solid pre- cipitate, probably owing to woollen fibres being much larger than those of cotton. Thus, with cotton and other stuff that will not imbibe freely solid precipitates, the mordant must be fixed within the fibre previous to applying the coloring substances, such as the vegetable decoctions. It will also be seen that the dye which is the product of combination between the mordant and color is not that of the natural color of the drug, but the color of the com- pound. Hence the great variety of tints capable of being produced from one dye-drug, by varying either the kind or intensity of the mordant. So that in the aliove instances, it is not the color of the hematoxylin fixed on the stuff, but its compound wilh iron, or tin, or alumina, as the case may lie, all of which give difi'ercnt tints. It is upon this principle of rendering bases insoluble while within the fibre by chemical means, that has brought to the use of the dyer a great number of mineral dyes which in themselves, whether separate or combined, have no attraction whatever for the fibre ; such as solutions of sulphate of copper, and yellow prussiate of potash, nitrate of lead, and bichromate of potash, kc. Suppose the stuff to be dyed a yellow by the two last-named salts, was first put into the solution of lead and then washed previous to being put into the bichromate solution, the greater portion of the lead would be dissolved from the stuff, and a very weak color would be obtained. If the stuff I'rom the lead solution was put directly into the bichromate solution, a very good dye would be the result ; but the portion of the solution remaining upon the surface of the stuff will combine with the chrome and form a precipitate which the fibre cannot imbibe, but will form an external crust or pigment upon the surface, which blocks up the pores, and exhausts to no purpose the dye, causing great waste : hence the stulF from the solution of lead is put into water containing a little soda or lime, and the lead is thus reduced to an insolulile oxide within the fibre. The goods may now be washed from any loose oxide adhering, and then passed through the bichro- mate solution, when the chromic acid combines with the oxide of lead, forming a perma- nent yellow dye. Thus it will be seen that whether the combination of the color with the stuff be chemical or mechanical, the production of the dye which is fixed upon the fibre is certainly a chemical question, and the dyer should be familiar with the nature and principles of these reactions. There are a few instances where the dye produced does not come within the sphere of these principles, there being no mordants required, nor any combination of the color fbrnicd within the stuff, but the dye-drug in its natural hue is fixed within the fibre. Such colors have been termed mbsfantivc, to distinguish them from those produced by means of mor- dants, which are termed adjective. Amongst this class of dyes and dye-drugs stands pre- eminent indigo-blue. Indigo in its natural state is entirely insoluble in water, and is of a deep blue color. The composition of this blue indigo is represented as — Carbon - - - - ^'' I Nitrogen - . . . l Hydrogen - - - - 5 | Oxygen - ... 2 But it is found capable of parting with a portion of the oxygen, and by so doing, losing entirely its blue color ; and in this deoxidized condition it is soluble in alkaline lyes and lime water ; this colorless compound is termed indigogene. The opinion of Liebig upon the constitution of this substance is, that indigo contains a salt radical, which he terms Anjilc.^ composed of C"^H^N. He considers that indigogene or white indigo is the hydratcd protoxide of this radical, and that blue indigo is the peroxide, represented thus : — C IT N O Water. Salt radical, anylc 1C> 5 1 Indigogene 16 5 111 Blue indigo IG 5 1 2 Advantage is taken of this property of indigo, of ]iartlng with its oxygen and becoming soluble, to ai)ply it to dyeing, and it is effected by the following means, when lor the pur- pose of dyeing vegetable stuff, as cotton ; and from the circumstance of these operations i)eiiig done cold, the method is termed the cold vat, whieh is made upas follows: — The indigo is reduced to an impalpable pulp, by being ground in water to the consistence of thick cream. This is ptit into a suitable vessel filled with water, along with a quantity of copperas and newly slaked lime, and the whole well mixed by stirring. After a .'ihort time the indigo is deoxidized and rendered soluble by a portion of the lime which is added in excess, the reaction being represented thus : — DYEING. 477 Indigo, composed of I J^'^^^^I^S"'^" ; ; ; ;- ^ Dyeing Solution. r Protoxide of Iron . ^^.C^ Peroxide of Iron. - „ Protoxide ot Iron 2. Copperas - - ^ guiphuHcAcid . [_ Sulphuric Acid TLime — / ^"-^ ^^^"^^ Sulphate of Lime. Lime - - - ] Lime -/_I__^^ Sulphate of Lime. I^Lime The peroxide of iron and sulphate of lime are precipitated to the bottom, and the indigo- gene and lime form a solution of a straw color, with darli veins through it. The operation of dyeing by this solution is simply immersion, technically, dipping. The stuff by immersion imbibes the solution, and wiien taken out and exposed to the air, the indigogene i/pon and within the fibre rapidly talces oxygen fi-om the atmosphere, and be- comes indigo blue, thus forming a permanent dye, without any necessary attraction Ijetween the indigo and the stuff. The indigo vat for wool and silk is made up with indigo pulp, potash, madder, and bran. In this vat the extracts of madder and bran perform the deoxidizing functions of the cop- peras in the cold vat, by undergoing a species of fermentation. Pastel and wood, either alone or with the addition of a little indigo, are also used for the dyeing of wool and silk stuff, the deoxidation being cfTected by the addition of bran, mad- der, and weld. In dyeing with these vats, the liquor is made warm, and they require much skill and experience to manage, in consequence of their complexity, being always liable to go out of condition, as the dyeing goes on, by the extraction of the indigogene and the mod- ification of the fermentable matter employed to deoxidize the indigo to supply that loss. The alkaline solvent also undergoes change, so there must be successive additions of indigo and alkali ; the principal attention of the dyer is the maintaining the proper relation of these matters, as too much or too little of either is injurious. Sulphate of indigo forms an intense blue solution, unaffected also by mordants. Vege- table stuffs dipped in this retain no dye, for the washing off the acid in order to preserve the fibre removes the color ; but animal fibre, such as woollen and silk, becomes dyed ; a portion of the blue remains upon the stuff after washing off the acid, being retained l)y capillary attraction. This dye is termed Saxon blue, but it has very little of the permanence of indigo or vat blue, although it is also a substantive color. Another truly substantive color is that dyed by carthamus or safflower, but the fixation of this dye upon the stuff differs from any of those referred to. Like indigo, it has no affinity for any base or substance capaljle of forming a mordant ; its solvent is an alkali, but in this dissolved state it does not form a dye. The mode of proceeding in dyeing with carthamus is first to extract the dye from the vegetable in which it is found, by soda or potash, which is afterwards neutralized by an acid previous to dyeing, which renders the color insoluble, but in so fine a state of division that no precipitation can be seen for some time, and the stuff immersed in this imbibes the color within its fibre, its lightness assisting this action, as the precipitate will remain suspended in water for days before it will subside. Vegetable fibre takes up this dye as easily as animal, but whether by an attraction for the stuff, or by a mechanical capillary attraction of the fibre, is not so easily determined. A piece of stuff suspended in a vessel filled with water, having in it some insoluble carthamine, all the coloring particles will flow to and combine with the fibre from a considerable distance, giv- ing a proof of the existence of some force drawing them together. Such then are the various conditions and principles involved in the processes of fixing the dye within or upon the stuff. During the operations of dyeing there are certain circumstances which have to be attended to, in order to facilitate and effect certain hues or tints of color. Thus, with many of tlie coloring substances, heat not only favors but is necessary for the solution of the dye, and also its combination with the stuff or mordant. Decoctions of woods are always made by liot water, and the dyeing processes with decoctions are in hot lirpior. When tlie coloring matter of quercitron-bark is extracted by boiling water, the color pioduced upon tiie stuff will be a rieli amber yellow, but if the extract be made by water at 180° Fahr., a beautiful lemon yellow will be the dye produced by it, using tlie same mordant in each case. Colors dyed Ity madder and Barwood must be done at a boiling lieat during the whole process, or no dye is effected. Sumacli, another astringent substance', is most advantageously applied at a boiling lieat; and in order to have a large l)ody of tliis dye fixed upon the stuff, it should be immersed in the liquor while hot and allowed to cool together, duiing which the tamiin of tlie dye undergoes some reniarkal)le change in contact witli the stuff. Safllower dyes are kept cold, so are tin l>ases, Prussian blues, and chrome yellows: liy applying heat to tlie last a similar result is effected to that with bark ; instead of a lemon yellow an amber yel- 478 DYEING. low will be obtained. Almost all colors are affected less or more by the temperature at which they are produced. Some mordants are fixed upon the stulf by heat, such as acetate of alumina ; the stuff l>eing dried from a solution of this salt at a high temperature loses part of the acid by b"ing volatilized, and there remal;.s upon the fibre an insoluble suboxide, which fixes the dye. These remarks respecting the methods apply more particularly to vegetable stuffs, as cotton, and in many cases also to silk, but wool is always dyed at a high heat. Although wool seems to have a much greater absorbing power than cotton, the lat- ter will absorb and become strongly dyed in a cold dye bath, in which wool would not be alfected ; but apply heat and the wool will be deeply dyed, and the dye much more perma- nent than the cotton. The [lermanence of colors is another property to be carefully studied by the practical dyer, as the color must not be brought under circumstances that will destroy its permanency during any of the operations of the dye-house. The word permanent, however, does not mean /«s/, which is a technical term applied to a color that will resist all ordinary opera- tions of destruction. As, for instance, a Prussian blue is a permanent color, but not a fast color, as any alkaline matter will destroy it ; or a common black is permanent, although any acid matters will destroy it ; while Turkey red is a fast color, and not affected by either acid or alkaline matters. A few of the circumstances affecting colors in the i)roccsses they are subjected to may be referred to in this place. If, for instance, the air in drying the dyed etufi" in a hot chamber be moist, there is a great tendency to the color being impaired in these circumstances. For example, a red color dyed with safilower will pass into brown, a Prussian blue will pass into a gray lavender, chrome yellows take an amber tint. Mostly all colors are affected less or more by being subjected to .strong heat and moisture ; even some of those colors termed fast are affected under such circumstances. A dry heat has little or no efl'ect upon any color, and a few colors are made brighter in their tint by such a heat, as chrome orange, indigo blue, on cotton, &c. Some of these effects of heat and moisture differ with different stuff; thus indigo blue upon cotton is not so much affected as indigo blue upon silk, while safflower red upon cot- ton will be completely destroyed before the game color upon silk will be perceptibly affected. The same coloring matter fixed by different mordants upon the same stuff is also differently affected under these conditions. Light is another agent effecting a great influence upon the permanence of colors, which should be also considered by the dyer. Reds dyed by a Erazil wood and a tin mordant, exposed to the light, become brown ; Prussian blue takes a purple tint ; yellow becomes brownish ; safflower red, yellowish, and these changes are facilitated by the presence of moisture ; such as exposing them to stiong light while drying from the dye-bath, cither out or within doors. The direct i-ays of the sun destroy all dyed colors ; even Turkey red yiekls before that agency. BoUinrj was formerly prescribed in France as a test of fast dyes. It consisted in putting a sample of the dyed goods in boiling water, holding in solution a determinate quantity of alum, tartar, soap, vinegar, .&c. Dufay improved that barbarous test. He considered that fast-dyed cloth could be recognized by resisting an exposure of twelve hours to the sunshine of summer, and to the midnight dews ; or of sixteen days in winter. In trying the stability of dyes, we may offer- the following rules : — That every stuff .should be exposed to the light and air ; if it be intended to be worn abroad, it should be exposed also to the wind and rain ; that carjH ts, moreover, should be subjected to friction and pulling, to prove their tenacity ; and that cloths to be washed should be exposed to the action of hot water and soap. However, such tests are not at all applicable to most of the colors dyed upon cotton stuff. Not many of them can stand the action of hot water and soap, oi' even such acids as the juice of fruits. Indigo blue, one of the most permanent dyes on cotton, yields its intensity to every operation of wasliing, even in pure water. 1. Red with blue produces purple, violet, lilac, pigeon's neck, mallow, peach-blossom, hJeii de roi, lint-blossom, amaranth. Thus a Prussian blue dyed over a safflower red, or vice versa, will produce any of these tints by varying the depth of the red and blue according to the shade required ; but the same shades can be produced direct by logwood and an aluminous or tin mordant ; the stuff' l)eing steeped in sumach liquor previous to applying the tin mordant produces the reddish or purple tint when such is required. 2. Red with black ; brown, chocolate, maroon, Szc. These tints are produced by vari- ous processes. To dye a deep orange by annotto liquor, and then form over it a black by sumach and sulphate of iron, gives a l)rown ; or dye the stuff first a rich yellow by quer- citron and a tin mordant, and tlien over the yellow produce a purple by passing it through logwood ; chocolates are thus ))roduced. A little Brazil wood with the logwood gives more of the red element. When maroon is required, the rod is made to prevail, and so by a judicious mixture these various tints are produced. Brown, especially upon cotton fibre, is more often produced direct by means of catechu. Steep the stuff in a hot solution of cate EDGE TOOLS. 479 chu, in which the gummy principle has been destroyed by the addition of a salt of copper ; then pass through a solution of bichromate of potash at boiling heat, when a rich brown is obtained. 3. Yellow with blue ; green of a great variety of shades, such as nascent green, gay green, grass green, spring green, laurel green, sea green, celadon green, parrot green, cab- bage green, apple green, duck green. Green is essentially a mixed dye, and produced by dyeing a blue over a yellow or a yel- low over a blue. In almost all cases the blue is dyed first, and then the yellow, and accord- ing to the depth of each or any of these are the various tints of green produced. ^Vith silk and wool, one kind of green dye may be produced simultaneously by putting sulphate of indigo into the yellow dye-bath, and then working the previously prepared or mordanted stuff in this. With cotton, an arseuite of copper (Scheele's green) may be produced by working the stuff in a solution of arsenite of potash or soda, and then in sulphate of cop- per, which produces a peculiar tint of green. 4. Mixtures of colors, three and three, and four and four, produce an indefinite diversity of tints : thus, red, yellow, and blue form brown olives and greenish grays ; in which the blue dye ought always to Ijc first given, lest the indigo vat should be soiled by other colors, or the "other colors spoiled by the alkaline action of the vat. Red, yellow, and gray, (which is a graduation of black,) give the dead-leaf tint, as well as dark orange, snuff color, &c. Red, blue, and gray give a vast variety of shades ; as lead gray, slate gray, wood-pigeon gray, and other colors too numerous to specify. See Brown Dye. Care must be taken, however, in mixing these colors, to study the depth of the tint re- quired ; as, for instance, were we wishing to dye a slate gray, and to proceed first by dye- ing a blue, then a red, with a little of the gray, we would produce, instead of a slate gray, a purple or peach. The arrangement referred to, applies only to the elements of the colors that enter into the composition of the various tints, so that a slate gray is a blue with a small portion of red, and a still smaller portion of the black element, that produces the gray tint. Tlius, dye the stuff first a deep sky-blue by the vat, then by passing through a solution of sumach, with a small quantity of logwood, Brazil wood, copperas, and alum, gray will be produced. The Brazil wood gives the red tint, sumach and copperas the black tint, the logwood assisting in this, and with the aid of the alum throwing in the puce or dove-neck hue ; and thus, by the variation of these hues by such arrangements, any of the gray tints can be produced. See Calico Printing. EBONY. Of this black wood three kinds are imported : — The Mauritius Ehony^ which is the blackest and finest grain. The Ea&t Indian Ebony^ which is not of so good a color. The African Ebony, which is porous, and bad in point of color. The ebony of the Mauritius is yielded by the Diospyriis Ebenus. Colonel Lloyd says this ebony, when first cut, is beautifully sound, but that it splits like all other woods from neglectful exposure to the sun. The workmen who use it immerse it in water as soon as it is felled for from six to eighteen months ; it is then taken out, and the two ends are secured from splitting by iron rings and wedges. Colonel Lloyd considers that next to the Mau- ritius, the ebony of Madagascar is the best, and nest that of Ceylon. The Mauritius ebony is imported in round sticks like scaffold poles, about fourteen inches in diameter. The East Indian variety comes to us in logs as large as tweirty-eight inches diameter, and also in planks. The Cape of Good Hope ebony arrives in England in billets, and is called billet wood, about from three to six feet long, and two to four inches thick. The uses of ebony are well known. White Ebony comes from the Isle of France, and is much like box-wood. EDGE TOOLS; more properly cx^Vh// tools, of which the chisel maybe regarded as tlie type. Holtzapffel, whose book on Mechanical Manipulation is the best to be found in any language, divides cutting tools into three groups, — namely, paring tools, scraping tools, and shearing tools. First. Paring or splitting tools, with thin edges, the angles of which do not exceed sixty degrees ; one plane of the edge being nearly coincident with the plane of the work produced, (or with the tangent in circular work.) These tools remove the fibres principally in the direction of their length, or longitudinally, and they produce large coarse chips or shav- ings, by acting like the common wedge applied to mechanical power. Secondly. Scraping tools, with thick edges, that measure from sixty to one hundred and twenty degrees. The planes of the edges form nearly equal angles with the surface pro- duced, or else the one plane is nearly or quite perpendicular to the face of the work, (or becomes as a radius to the circle.) These tools remove the fibres in all directions with nearly equal facility, and they produce fine dust-like shavings by acting superficially. 4b U ELASTIC BAiJDS. Tliirdly. Shearing, or separating tools, with edges of from sixty to ninety degrees; gen- erally duplex, and then applied on opposite sides of the substances. One plane of each tool, or of the single tool, coincident with the plane produced. ELASTIC BANDS. {2'tssus ilastiques, Fr. ; Federltavz-zeige, Gefm.) See Caoutchocc and Braiding Machine. ELASTICITY. The property which bodies possess of occupying, and tending to occupy, portions of space of determinate volume, or determinate volume and figure, at given pres- sures and temperatures, and wliich, in a homogeneous body, manifests itself equally in every part of appreciable magnitude, {Nuhol.) The examination of this important subject in Kinetics does not belong to this work. A few remarks, and some explanations, only are necessary. Elastic Pressure is the force exerted between two bodies at their surface of contact. Compression is measured by the diminution of volume which the compressible (elastic) body undergoes. The Modulus or Coefficieiit of Elasticity of a liquid is the ratio of a pressure applied to, and exerted by, the liquid to the accompanying compression, and is therefore the recip- rocal of the compressibility. The quantity to which the term Modulus of Elasticity was first applied by Dr. Young, is the reciprocal of the extensibility or longitudinal pliability. (See the Edinburgh Transactions, and those of the Royal Society, for the papers of Barlov, Jfnxircll, and Jia7iki7ie, and the British Association Reports for those of Fairbairn, Hodg- kinson, &c.) Various tables, showing the elasticity of metals, glass, &c., have been constructed, and will be found in treatises on mechanics. The following notices of the mechanical proper- ties of woods may prove of considerable interest. The experiments were by Chevandier and Wertheim. Rods of square section 10 mm in thickness and 2 ra in length were prepared, being cut in the direction of the fibres, and the velocity of sound in them was determined by the longitudinal viljrations, their elasticity from their increase in length, and tlicir cohesion by loading them to the point of rupture. Small rods were cut in planes perpendicular to the fibre grain, (in directions radial and tangential to the rings of growth,) and their elasticity and sound velocity were measured by the lateral vibrations. It was thus again established, that the coefficients of elasticity, as deduced from the vibrations, come out higher than those derived from the elongation. Nnmea of the wooJb. Density. Sjund velocity. Coefficients of elasticity. CohebioD. L. E. T. L. Pv. T. L. E. 0-7] T 14-9 1216-9 7-93 0-493 13-96 8-05 4-72 1113-2 94-5 34-1 4-18 0-220 0-756 11 -SO 10-28 7-20 1085-7 208-4 103-4 2-99 1 -007 0-&12 13-32 6-46 9-14 997-2 81-1 155-2 4-30 0823 0-S2.3 10-06 11-00 8-53 9804 269-7 159-3 8-57 0-885 0-S08 — — — 977-8 — — 6-49 — 0-ST2 11-58 9-24 7-76 921-3 lSS-7 129-S 5-66 0-5S2 0-&59 lu-on S-53 4-78 564-1 97-7 28-6 2-48 0-256 0-69-2 13-4.3 9-02 685 1I63-S 134-9 80-5 616 0-522 0-697 14-05 8-39 7-60 1121-4 111-3 102 678 0-21S 0-601 13-9.5 8-25 6-28 llOS-1 9S3 59 4 4-r)4 0-329 0-602 15-30 9-72 5-43 1075-9 107-6 43-4 7-20 0-171 674 1-2-36 9-26 6-23 1021-4 157-1 72-7 3-5S 0-716 0-477 12-&9 S-44 6-82 517-2 73-3 38 9 197 0-146 — — 8-56 6-11 — 122-6 63-4 — 0-345 Acicia Fir - Hornbeam Birch Beech Oak - Hohu-Oak Find - Svramoro - Asli - Al, and the zinc z does not considerably exceed in size the metal ?/;, the conditions will be complied with for depositing copper in a compact reguline form. It is obvious that, with this arrangement, m may be a mould or other form in metal, and that a copy of it may be obtained in copper. Fusible metal, consisting of 8 parts of bis- muth, 4 of tin, 5 of lead, and 1 of antimony; or 8 parts bismuth, 3 tin, and, 5 lead, is much used for taking moulds of medals. The ingredients are well melted together and 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 witli a card, and tlie cold metal is eitlier 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 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 cun-ents 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 ji(j. 261, where a is a DanieU's cell, as 2G1 in fig. 259 ; and b a trough filled with an acid soliitioa of sulphate of copper; m is a metal rod, on which the moulds are hung ; and c a metal rod, upon wliicli plates of copper arc hung facing the moulds ; the copper-plates are connected by the wire z with the coiii)cr of the battery cell, and tlie 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 coll ; thence by the wire ,? to the plates of copper c ; through the sulphate solution to the moulds m ; and thence by the wire x to the zinc rod. In this arrangement, no slielf is necessary in the trough n for crystals of sulphate of copper to keej) up the strength of the solution ; for the nature of tiie clectro-clicmical decompositions is such, that in proportion as copper is al)stracted and deposited upon the moulds ??;, other copper is dissolved into the solution from the plates c. Water is tiie prime subject of decomposi- tion. It is a compound body, consisting of tiie gases oxygen and hydrogen, and may be represented by fi(j. 202, where the arrows show the direction in which the current, by the wire /), enters the trough b oi fi(j. 201 by the plate of copper c, and passes through the 492 ELEOTEO-METALLURGY. /^ 262 0300(20 water in the direction shown, and leaves it after traversing the mould by the wire n. Two atoms 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', (bracketed 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 hydrogen h', belonging to the second atom of water, is set free and rises in the form of gas. The explanation is to show that oxygen is liberated where the current enters, and combines there in •"^ .^ x^ ^ its nascent state with cop/icr.- 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 witho>it 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 6. 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 supj)ly 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 DanielFs or Smee's cells arc 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. Skals 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 ; fastening 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 lirown paper cell. ri,.\sTF,R 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 firj. 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 pcrcha. This is treated with black-lead, and in other respects the same as seals. ELECTEO-METALLURGY. 493 Wood-cuts are treated with black-lead, and a copper reverse 13 deposited upon them. This is used as a mould to obtain electrotype duplicates, or as a die for striking ofiF dupli- cates. Stkreotypk 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 backing up with melted lead. Old Brasses may be copied by the intervention of plaster. Embossed cards or paper may be copied by first saturating with wax and then using black-lead. FiitJiT 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 STATU KTTES, 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. Silver 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. 201, 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- trotype. 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. 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. Wliile the impression is wet, the paper face downwards is pressed upon a polished plate of copper. 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 pota.ssium, 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 siereo-t/li/phic 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-clotii was made by saturating the fibre of canvas or felt, making it conducte- ous in tl\e usual way ; it was proposed in place of tarpaulins as a water-tight cover. Retorts and cituciiiLKS, &c., of glass or porcelain, have been successfully coated with electrotype copper l)y 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 togetlier in the sohition of sulpliate of copi)cr, and cionncctcd with the battery as for ordinary deposition. Parts not included in tlie process are protected ofl' 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 494 ELECTRO-METALLURGY. its surface without the aid of the voltaic apparatus. The iron surface is imperfectly cov- ered with copper ; no firm perfect deposit occurs. In order to obtain solid deposits of cop- per on iron, it is necessary to use a solution that has no ordinary chemical reaction upon iron. Cyanide of copper is used, which may be obtained by dissolving sulphate of copper in cyanide of potassium. This solution requires to be raised to and retained at a tempera- ture not greatly below 200°, in order to give good results. Electro-zixcixg is applied to surfaces of iron, in order to protect them from corrosion. A solution is made of suljjhate of zinc, which is placed in a trough b. Jig. 261. Two or three battery cells are required. The iron to be zinced is connected with the zinc end of 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 has been successfully produced as a coating upon a copper surface. Separate solutions are made of sulphate of copper and of sulphate of zinc in cyanide of potassium. The two solutions are then mixed, and placed in a decomposing trough. Two or three cells of a battery are used, and a brass plate connected with the copper end. An electrotype copper medal or other prepared stn-face is connected with the zinc. Urilliant 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 throwni 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. y{)ace 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; tetnihedrai crystals of proto-chloride of copper; octahedral crystals of sulphide of silver ; crystals of subnitrate of co|)per ; bibasic carbonate of copper, and others too nu- merous to name, have all been formed by slow voltaic actions. The alkaline metals, potas- siuni, sodium, etc., were first obtained by Davy in the galvanic way ; magnesium, barium, aluminium, calcium, &c., are obtained by M. Bunscn by operating upon the chlorides of these metals either in solution or in a state of fusion. Electro-etcming is produced at the place where the current entcra the decomposing trough, as at the copper-plates c of Ji p. 261. A plate of copper is prepared as if ibr 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 tlic trough B, containing cither 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 stcipjicd 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. Dagcerreottpe ETi hing is a delicate operation, and requires much care. The solution employed by Professor Grove was Jiydrochloric 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 PnoTO-GALVA.NO-GRAPiiic 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. lie then treats the glass or plate with these, and in the usual way takes a picture. lie washes the gelatine picture with water, or solu- tion of l)orax 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 ol)taining an "engraved plate from which to print. See Puoto- OUAl'IIIC ENGr.AVlNG. 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 electrotvpc operation is complete, the design is in relief instead of being in intaglio, as in ordinary etching. Mr.TAr.i.o-cnROMES 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 arc required. A steel plate is laiil 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 ELECTRO-METALLURGY. 495 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 bhies ; lake, bluish lake, green and orange, greenish violet, and passing through reddish yellow to rose-lake, which is the last color in the series. According 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 addition to this, a pattern in card or gutta percha is cut out and interi)osed 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 the experiment. The different colors are due to the different thicknesses of the thin lilnis of peroxide of lead. M. Becquerel proposed the deposit of peroxide of lead, and also the red peroxide of iron, for protecting metals from the action of the atmosphere. For the latter, prutosulpluite of iron is dissolved in ammonia solution, and operated upon by two or three batteries. The most important application of electro-metallurgy in the arts has been for plating and GILDING, which is most extensively carried on both at home and abroad. Results that were unattainable, and others attainable only at great cost, are readily produced by this mode of manipulating. The liquids most in use are the cyanide solutions, first introduced by Messrs. Elkingtons. They are prepared in various ways. Cyanide of j)otassium is added carefully to dilute solution of nitrate of silver ; and the white deposit of cyanide of silver is washed, and then dissolved in other cyanide of potassium ; or lime water is added to the nitrate solution, and the brown deposit of oxide of silver is washed, and, while moist, is dissolved in cyanide of potassium ; or common salt is added to the nitrate solution, and the white deposit of chloride of silver is washed and dissolved in cyanide of potassium. Or a solution of cyanide of potassium is placed in the trough b, fig. 261 ; and the current from three or four cells is passed into it from a silver plate at e, which combines with and is dis- solved into the liquid, converting it into a cyanide of silver solution. To prevent silver being abstracted by deposition at ?», as the current leaves the trough, the metal at »/i is placed within a porous cell of cyanide solution, so as to limit the action. Gold solution is obtained by dissolving the anhydrous peroxide of gold in cyanide of potassium, or by treating chloride of gold with cyanide of potassium, or by using a gold plate and a voltaic current with a solution of cyanide of potassium in the same way as de- scribed for silver ; and allowing the action to continue until the solution is sufficiently strong of gold. With these solutions electro-plating and gilding are readily accomplished. There are other solutions more or less valuable, which wilf be found in the books that treat upon the subject. Fig. 266 is an arrangement for operations on a small scale. The vessel a b, containing 266 the gold solution, rests over a small stove or spirit-lamp. The objects to be gilt are sus- pended by wires to the conducting rod d, in connection with the zinc end of the battery ; and the gold wire or plate c is connected with the other end. A temperature of from 100" to 200' is desirable ; the higher temperatures require fewer battery cells ; with the highest, one will suffice. The solution of course evaporates under the influence of heat ; and dis- tilled water must be added to supply the loss, before each fresh operation. Plating and gilding is successfully, and, in point of economy, advantageously carried on at Birmingham, in more than one manufactory, by means of magnetoeiectricity. In the article on Electkic-Ticlegkapiiv, will be found a description of this form of electric force, and the means by which it is produced. An electro-magnet is set in motion in front of the poles of a perinanent magnet, in such a manner that the soft iron core of the electro-mag- net becomes alternately a magnet and not a magnet; in the act of becoming a magnet, it raises up a current in one direction in the wire wjth which it is wound ; in the act of ceas- ing to be a magnet, it raises up a current in the reverse direction. The ends of the wire 496 ELECTRO-MOTIVE ENGINES. are led away and insulated. The instrument is fitted with a commutator, so adjusted that it collects the currents from the ends of the wire, and guides them in a uniform direction into the vessel that contains the solution and articles to be gilded or plated. In practice a single machine consists of many electro-magnets grouped together, and many powerful ma<'- nets for exciting them ; by which means a continuous flow of a large amount of electriciry is obtained. Fig. 267 is an illustration of such an arrangement as adapted by Mr. Wool- rich : a a a a are four clusters of permanent steel magnets, seen from above ; b b b b b \s the frame-work of the machine ; c c c c are four bars of soft iron, wound with large size insulated copper wire ; J is a circular disc, on which they are mounted and which rotates on a vertical axis, of which / shows the upper end ; e is the commutator, from which two wires are led off to the solution to be operated upon. The permanent magnets are U- shaped ; one pole only of each bundle is visible ; the other is beneath the disc d, and its freight of electro-magnets c c, &c. The axis is set in rotation by a strap passing over the drum of a shaft of the steam-engine, that does the ordinary work in a factory ; and the disc carries the electro-magnets between the poles of the permanent magnets, and exposes them to the most favorable action of these poles. The number of coils and magnets vary in proportion to the work required. By this arrangement not only does each coil pass under the influence of many magnets, but each magnet acts successively on many coils ; and a proportionate supply of electricity is the result. — C. V. W. ELECTRO-MOTIVE ENGINES. Electro-magnetism undoubtedly affords an almost unlimited power. An electro-magnet may be constructed which shall have a lifting power equal to many tons. It is probable that there are limits beyond which it would not be pos- sible to increase the power of electro-magnets ; those limits have not yet been reached ; but supposing them to be attained, there is nothing to prevent the multiplying of the num- ber of electro-magnets in the arrangements. It may be stated, in connection with this part of the subject, that from experiments made with Hearder's magnetometer, it appears that the development of magnetism in iron observes,some special peculiarities. These may be thus stated : — With the same electro-magnet there is, as the voltaic pairs in the battery are increa.sed, a gradual increase of magnetic force. With from one to seven elements there appears an average excess of .31 lbs. ; after this point, with the increase of battery power, by the addition of pair after pair of zinc and platinum elements, the production of power bears a decreasing ratio to the power employed, and at last, the addition of five elements was not found to produce an increase of effect equivalent to the value of one element. In all experiments, therefore, on electro-magnetic machines, the experimentalist has first to determine the utmost power which the soft iron is capable of assuming, in relation to, — ELECTRO-MOTIVE ENGINES. 497 1st. The number of coils of wire on the iron ; and 2d. The number of elements employed in the exciting source — the voltaic battery. The length of the iron and its thickness are also points demanding special considerations from the constructor of an electro-magnetic macliine. There remains now to examine the production of the power, Electro-Magnetism. The electro-mechanician is dependent upon his battery, in the same way as a steam en- gineer is dependent upon his fire and his boiler, for the production of mechanical effect. Voltaic batteries vary in their effects, and hence arise statements which differ widely from each other, as to the result obtained, by the destruction (? change of form) of a given quantity of metal in the battery. Dr.Botto states, that 45 lbs. of zinc, consumed in a Grove's battery, are sufficient to work one-horse power electro-magnetic engine for twenty-four hours. Mr. Joule says the same results would have been obtained, had a Daniell's battery been used, by the consumption of 75 lbs. of zinc. It is impossible, oh the present occasion, to enter into the theory of the voltaic battery, or to describe the varieties of arrangement which have been adopted for generating (de- veloping) electrical force in the form of a current, with the greatest effect, at the smallest cost. On this point the evidence of Jacobi may be quoted : — " With regard to the magnetic machine, it will be of great importance to weaken the effects of the counter current, with- out at the same time weakening the magnetism of the bars. It is the alternate combination of 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- ing 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 cliange of state the quantity of heat developed has a constant relation to the chemical action going on. Mr. Joule has proved by a scries of most satisfactory experiments, that " the quantity of heat capable of increasing the temperature of a pound of 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 Hue! Towan and the United Mines, the combustion of one pound of Welsh coal evaporates of water, from its initial temperature, lO'SS" 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 sefin motion ; but the quantity available for use, falls very far below the whole amount developod 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. Joule 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 practically obtained. A great number of experiments, made by the Author some years since, enabled him to de- termine, as the mean average result of the currents produced by several forms of battery power, that one grain of zinc, consumed in the battery, would exert a force equal to lifting 86 lbs. one foot high. Mr. Joule and Dr. Scoresby thus sum up a series of experimental 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 foot 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 high. 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 en- gines, at less than £1 per ton ; and the carbon clement 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 reprusents the theoretical mechanical power. Therefore the atomic weight of the carbon atom being G, 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 niore economical to burn zinc under a boiler, and to use it for generating steam-power, than to consume zinc in a voltaic batterv 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 Awerhan, recommends the follow- ing as useful recipes for the electro-metallurgist. Be says : " I believe 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 Cymikle of Silver. — 1. Dissolve 1 oz. of pure silver in 2 oz. of nitric acid and 2 oz. 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 Ci/anide 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. 7o Prepare C'l.'ati- 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 iirocced 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 S'lver to such metals as iron, steel, Britannia metal, and German silver; the second to finish the work, as any amount of silver can be dei)osited in a reguline state from the second solu- tion. First., or miiteiiing Solution. — Dissolve 2^ lbs. (troy) of cyanide of potassium, 8 oz. carbonate of soda, and 3 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 Finishinci Solution.— Dissolve 4-^ oz. (troy) of cyanide of potassium, and \h 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 batterv, 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 ELECTRO-TELEGKAPHY. 499 two cells. Gold can be deposited of various shades to suit the artist, by adding to the solu- tion of gold a small quantity of the cyanides of silver, copper, or zinc, and a few drops of the hydro-sulphuret of ammonia. ELECTRO-SORTING APPARATUS. M. Fromcnt 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 pulverized 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. 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, others more complex ; and, according as one or other cause is in operation, the conditions under which the electric force is manifested vary ; some conditions being very unfavorable, and 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. Oondnction is well illustrated and turned to useful account in the iron and copper wires, by which distant telegraph stations are connected with each other; insulation^ 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 iu 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 mucli 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 whicli a long length of wire was actually used, was actuated by this form of electricity. In ISlC), 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, lialls of eliler pith, produced under circumstances analogous to those to which we have already referred. At the far end of his telegraph wire two pith Ijalls were suspended close together. Electricity applied at the home end of the wire at once diffused itself throughout the conducting system, inilud- ing the pair of light balls. Just as we have seen gold leaf recede after having apjiroachcd 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 500 ELECTRO-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 htation ; the clocks were so regulated as to be synchronous in their movements ; each of them car- ried, in lieu of a hand, a light disc, having the letters of the alphabet and other signals en- graved on it. The disc was hidden by a screen, in which was one opening. It is obvious that if the clocks were started together, and had uniform rates, the same letter at the same time would be visible through the opening in each screen ; and letter by letter would 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 iiass 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 tliis 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 airangemcnt 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 dcsiral)lc 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 tlicni, 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 thr.t 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. K (_/fy. 2C8) 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 connected 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 arc 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 negative ; and both are in a condition to discharge, citlier each to the other, by means of a wire led from one to the other, or eacli 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 wire) leading to the earth at a distant place. The resistance to be overcome is, in the former case, less ; and the current of force in cireiihuion is proportionately greater. Under whatever circumstances a wire takes part in promoting the discharge of an apparatus of this kind, the whole of the said wire is in a condition to indicate the presence of the force that is pervading it ; and as the force may be 268 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 the battery, may be pre- sented to the given end of the telegraph wire, the rela- tive condition of the wire will be modified according- \y. 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 j!;/. 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 tlie 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' d vr w u A z' 6 B z. If a companion instrument were in any part of the circuit of the wire w \v, it would correspond in its signals with the home instrument, fir/. 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 crcri/ foot of the 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 effect is multiplied in proportion to the length of wire so concentrated. This is managed by covering a considerable quantity of fine wire with silk or cotton, and winding it on a frame a, (_/?//. 268,) suspending the needle within the frame. Such an instrument is called, from its properties, a mulfiplier. It is seen at a glance that the wire of the multi- plier is an aillilion over and above the length of the actual telegraph wire recjuircd for reaching the distant station, and thu'^ it practically increases the distance to l)e traversed : its smallness adds to this. The multipliers connnonly used add a resistance equal to six or seven miles of telegraph wire. 502 ELECTRO-TELEGRAPHY. Let us now turn to the face of the instrument Here which IS on the same axis as the n.agnetized needle above fle<;ted to the right or left, and limited in Its motion by ivory pins. We have a handle lor 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 ol deflection being used for the va- rious letters, as sliown on the engraved dial. 1 lis is Cooke and Wheatstone's sin- gle needle instrument. Jiff. 269. The form and cliaracter of their double needle instrument is shown in fiq 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 eitlier or both needles, accordiii"- to the code engraved on the dial, constitutes the alphabet. This instrument is very exten- sively emjiloyed ; messages are sent by it witli extreme rapidity. Another property possessed by a wire conveying a current, is that of converting we have a dial and described, capable of an index, being de- ELECTEO-TELEGRAPHY. 503 soft iron, for the time, into a magnet. Tiie 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 mechanical 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 necessary in order to obtain a useful result. The simplest application of this principle is shown in Jig. 271. Here are two brass reels, filled with cotton-covered copper wire, in one length. They are hollow, and a U- sliaped bar of iron passes through them, presenting its ends at the - ' ^ face turned toward us in the draw- in,'. This bar becomes magnetic — forms what is called an electro- magnet — every time and as long as an electrical current circulates in the wire ; and its ends be- come respectively north and south poles. A narrow plate of iron, an armature, as it is termed, is mounted on pivots in front of the ends or poles of the magnet ; it carries a vertical stem upon which the 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 o:ie 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 inde.x, 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- 272 l^m^^ 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 tlie lever p, which is itself carried on centres at <•. The range of mo- tion here is small in order to produce rapid utterance ; it is regulated by the screws d ami i. The reaction of the spiral spring / 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 u[)on the end of the paper slip. Wc 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 deseril)ed, 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 504 ELECTRO-TELEGRAPHY. produce a mark, is such that it cannot conveniently be produced hy tlie magnetic attraction derived from a current of electricity that has come from a far distant station in order to circulate in the coils of wire m. This dilficulty does not prevail in the signal-bells, fig. 271, which are, at most, not required to be more than eight or ten miles apart, and in which also momentum can be and is accumulated so as to conspire in producing the final result. Morse has, therefore, had recourse to a rela;/, as he calls it. This, in ])rinciple, is pictty much the same thing as the instrument itself ; but it has no heavy work to do, no marks to make ; it has merely to act the part of a C(mtact-maker or key ; it can hence he made very delicate, so as to act well by such currents as would not produce any motion in the instru- ment itself. The batteries which furnish the electricity lor doing the actual printing work in Morse's telegraph, are in the same station with the instrument itself. The office of the 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 wny. 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 othir. The relays are constructed with much finer wire than is required for the instrument itself, 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. 273 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, {fg. 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. Jig. 274 ; t is the bell ; in m is the double- headed hammer, which is in fact the pendulum, attached to the pallets /", which work in a scapc-wlieel hidden in the figure, and in gear in the usual way with a coiled spring in the box h, by the train r,, j-j, rs, >•■:. The electro-mag- netic part here, as in other instruments, is simple enough ; rt r is a lever moving on a centre above /, having at one end an armature n^ facing the poles of the electro-mngnct c \ and at the other end r, a hook which facCs the wheel ?•, and by catching in a notch on its circumference, keeps the train at rest. But when a current circulates through the coils r, 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 mngnetism 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. 505 The telegraph originally adopted and still largely used by the French Administration, is somewhat akin to the ahirum just described. It has a train of wheels, a scape-wheel with four tectli, and a pair of pallets. There is, however, no pendulum ; Ijut the pallets are con- nected with the armature of an electro-magnet, in such a manner that, for each attraction or repuls'oii 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 consecutive attractions and repulsions, produce a whole revolution of the scape-wheel. Tiie axis of the latter projects through the dial of the instrument, {Jig. 275,) and carries an arm 275 a or b, ( fig. 276,) which, following the motion of the wheel, is able to assume eight distinct positions. The apparatrus 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, tig. 276 is a front view of the two arms ; part of the 276 dial is supposed to be removed, so as to ex- pose the four-toothed wheel already men- tioneil, and the pallets x and .; ; which, in their movement to and fro, allow of the seaii-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 eacii of the poles ; the horns or cusps of the respective crescents are facing and near to each other ; and a magnetized steel needle is l)alanced between thein. This arrangement is scunewhat like the following ( | ). So long as no current is circulating in the coils of the electro-magnet, the cn-scents 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 L 50G ELECTRO-TELEGEAPHY. right-hand crescent are north poles, those of the left south poles, and the top end of the needle is north. Four forces will conspire to move the needle to the left. Its top will be attracted by the left-hand crescent and repelled by the right ; its bottom will be repelled bv the left, and attracted by the right. When this current ceases to circulate, the simple attraction between the magnetized needle and the soft iron of the crescent tends to retain it in a deflected position. This tendency is increased by a little residual magnetism, that is apt to remain in the best iron, notwithstanding every care in its preparation. In order, therefore, to restore the needle to its normal position, a short quick current in the reverse direction is given. These instruments are single or double. Only one kind of deflection of the needle is available for actual signals, the other motion being merely the return to the normal state. The single needle alphabet is composed of deflections of a short or a long duration ; these are produced by holding on the current for an instant or for more than an 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 either 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 a7id 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 mcKj- nelo-elcrtric 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 fy. 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 TJ 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, coining from a long distance, had to be received in Morse's arrangement [fg. 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 sent 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 n, 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 mngnets, 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-shapcd 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 mug ELECTRO-TELEGRAPHY. 507 net.-, the permanent and the electro, shall be flush with each other, or in the same plane. A couple of iron armatures are mounted on a disc in front of the magnets. The disc has a motion on a centre ; the armatures are curved or crescent-shaped. Their form is so ad- justed to the relative positions of the poles of tlie respective magnets, that, in their normal or ordinary position, one crescent connects the N. pole of the magnet with one, say the 2ipper pole of the electro-magnet, and the other crescent connects tlie S. pole of the per- manent magnet with the lower pole of tlie electro-magnet. On pressing a key the disc moves, 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 arrangement 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 the 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 Uttle weight to move in signalling. We have shown how an electric current generates magnetism, and how magnetism gen- erates 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 a!l the properties of magnetism, and among them that of pro- ducing another current in another wire ; aitS so it is. A few convolutions of a large-sized wire are coiled round an iron rod ; and outside the larger wire is a very great length of finer wire. The current from the battery is called the primary current in this arrange- ment ; and the moment it begins to circulate in the large wire, it magnetizes the iron and generates a current, culled secondar;/, in the fine wire, which is able to penetrate to a very 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. Tiie 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 far 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- 278 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, similar to that employed in Morse's telegraph. He causes the paper b {Jiff. 278) to pass over a drum of brass R, between the metal of n and an iron point or stylus p. The electric current enters the apparatus by the point p, passes through the solu- tion of cyanide of potassium, with which the paper B is saturated, and out by tlie spring p', which is in metallic contact with the drum k. 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 supi)lie(l 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 which motion anil chemical action each play their part. The .secondary currents that he em])loyed were not able to produce the chemical decomposition that he reipiires 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- 508 ELECTRO-TELEGRAPHY. ill" apparatus, which consists of a ribbon of paper, saturated with a thenueul suUitioii, and passing between a drum and a steel point. We should exceed our limits, were we to attempt the description of some of tlie many other forms that have been proposed. The above are good illustrations of the leading prin- ciples, and are all in successful use. Some telegraphs will print in ordinary characters ; this result is only attained by much complexity ; and its value is more than questionable, it being as ejii^y 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 tliey acquire their knowledge in a very short time. Hence, probably, it is that telegraphs to print in ordinary characters arc but little known in real practice ; nevertheless, some very promising instruments of the class have been produced, by House, and especially one more recently by Hughes, both of tlie I'nitcd 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 arc the number of marks or signs in printing, and in each kind of tele- graph. 1. Single ^ Cooke f /// and '1 ^" Wheat 2. Double I stone. /// 3. Single -1. Double 5. Morse - 6. Single ^ 7. Double Henley Mil Bain -^1 _ W V / III Hill nil IIW l\\\l Ml Mil \ll W // \/ \/ 20 13 'l6 19 15 17 h6 The Rheo-ehctro-static system of telegraphy was fir.st 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, {fcj. 268,) for the purpose of reducing the amount of battery power required under otlier circumstances to be maintained. The wire, by which a pair of IdcIIs 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 tjpposed to and balanced against each other. Under these cir- cimistances, the wire is in a null, or rheo-clectro-static state; neither current circulates. If the connection of one of the lialferies is reversed, so that its negative pole is presented to the wire, tl)en the currents of iioth batteries are in the same direction, and they circulate as one current, equal in value to the combined force of the two liattcrics. The application is obvious ; that, whereas, under the ordinary system, a v-hoh battery, of force sufficient to traverse the distance and do efTective work, must be at each station, under this S3'stem only Art//" such battery is necessary at each station, for producing the same effective work. Also, if a little more battery power is pl.iced 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 ami 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 lino wire, each battery current is made to circulate through its own signal-bell every time the earth and line wire are placed in coimection. 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 comnnmication with the earth on the open railway for mak- ing distress signals, f)r otherwise the discharge is imperfect, and no signal is made. P'ish- jointed rails are very valuable for this purpose ; in their absence, especially at embank- ments, metal must be buried for the pm-pose at intei-vals in the moist earth, and a wire attached for use. Contact springs on tliC telegraph poles are proposed. ELECTRO-TELEGRAPHY. 509 o Telegraph wires are suspended to poles by insulators of earthenware, glass, or porce- lain ; the material and shape varying according to the experience of the engineer and the lengtli of line to be insulated. In very short lengths, the battery power required for over- coming tlie resistance is not great ; it will therefore not overcome the resistance of an insu- lator of moderate quality, and escape to the pole and thence to the earth ; but the bat- - ' ^ tery power required to overcome the resist- ance of very long lengths of wire is equally able to overcome the resistances presented by inferior insulators, and to escape in con- 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 expended in constructing insulators. Fine porcelain is most in favor, from its present- ing a very smooth surface, and being less hygrometric than glass ; and it is distorted into most mysterious-looking shapes in order to present as great a distance, and one as much sheltered as possible, between the part with which the line wire is in contact, and the part that is in contact with the pole. For subterranean and submarine wires still greater care is necessary, because they are in the very bosom of the earth or sea, to which the current will escape, when and where it can, in order to complete the dis- charge. Fig. 279 represents the cable that has been lying in the British Channel be- tween Dover and Calais, since September, 1S5I. It contains four No. 16 copper wires ; each wire is doubly covered with gutta per- cha. The four wires are then twisted into a rope, and the rope is thickly covered, first with hempen yarn, tarred, and finally with a jacket of ten No. 1 iron wires. The cable is shown in perspective and in section. Fiff. 280 shows the perspective and section of the Irish, a single-wire cable. It consists of a single central conductor, of one No. 16 cop- per wire, doubly covered with gutta percha, then with hempen yarn as before ; and final- ly with a protecting jacket of ten No. 8 iron wires. The Calais cable weighs 7 tons per mile ; the Irish, 2 tons per mile. The At- lantic Telegraph cable, of which nearly 3,000 miles were prepared, is in section, just the size of a silver threepenny piece. It is a single-wire caljle ; the wire was a strand of seven No. 22 copper wires, trebly covered with gutta percha, then with yarn, and pro- tected with eighteen strands of seven wires each, of No. 22 iron wire. It wejghs 19 cwt. to the mile. This cable is lost. The iron jacket is in disrepute now for deep-sea cables. Ilemi) is preferred. Telegraph signals pass with far less rapidity through buried and through submnrine 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 surf\ice of the gutta percha that is in immediate con- tact with the cnmlucting wire. Nor is this all ; before a set-oiid 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 |)ro- 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. 510 EMAIL OMBRANT. EMAIL OMBRANT. A process which consists in flooding colored but transparent glaives over designs stamped in the body of earthenware or porcelain. A plane surface is thus produced, in wliich the cavities of the stamped design appear as shadows of various depths, the parts in highest relief coming nearest the surface of the glaze, and thus having the effect of the lights of the picture. This process was introduced by the Baron A. De Trem- blay, of Rubellcs, near Melun. EMBOSSING WOOD. A process which may be regarded cither as carving or emboss- ing wood, is that patented by Messrs. A. S. Braithwaite & Co. Oak, mahogany, rosewood, horse-chestnut, or other wood, is steeped in water for about two hours ; and the cast-iron mould containing the device is heated to redness, or sometimes 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 oft" volumes of smoke, but no flame. After a short time the iron is returned to the furnace to be reheated, the blackened wood is well 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 heated 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 materially influenced by the character and condition of the wood itself, and the degrees to which heat 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 Snnta 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., 2V5 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 £5C)0. 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 in-ches 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, Ijut 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 chlorophifle. 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 l)y Henry Bone, R. A., and hrs son, the late Henry Pierce Bone, who have produced the largest enamels ever painted ; and ))eyond the time and consequent expense there appears no practical limit to the size of enamel paintings. Prepnrinr! 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 irregularly, producing imdulations over the plate, perfect flatness being next to impossil)le for large pictures. The copper is then laid face downwards on the convex wooden mould used for sh.iping, 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, and then it is smoothed with a steel spatula. This forms the back of the plate, and when fired this part is finished. The copper is now reversed on a convex board the exact counterpart of the other, and covered with white enamel ground fine in the same way as above. The plate is now ready for firing, and after it has been fired and cooled, the sur- face must be ground smooth with a flat piece of flint or other hard substance, with silvpr 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 iu the furnace, the exact shape of the plate as originally made, which must be used in all subsequent firings. After the whiting is formed 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, 287 and experience has shown that it tends considerably to keep the plate in its original .shape. When the plate is small, (up to three inches in length,) it may bo annealed for pass- ing into the hot muffle as follows : — The planche bearing the plate may be placed on another planche heated in the muffle and placed in the front of the muffle for a few min- utes, 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 ^, pianrho firing, it should be placed on another hot planche and b Bed of whiting. 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 the 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 returued to the shelf of the annealing-box, and left there till quite eold^ 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 nothing of an encaustic character about them. ENGRAVING. Engraving on metal plates may be cla.s.sed under the following heads : Elckinfiy 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 shoidd be freciuently and carcM'nlly sharpened. This is best done by turning the needle round in the fingers while rubl)ing 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 ptrfeetly round. The dn/-poi?it 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 sijnarc ; the former being used for cutting fine lines, the latter for l)r()ad : the giaver fits into a handle about five inches and a half long, and it shotild be well tempered before using — an opera- tion requiring great care. The angle at the meeting of the two lower sides is called the bdly, and the breadth of the end, the fare. To sharpen the former, lay one of the flat sides of the graver on the oilstone, keeping the right arm toleralily clo.'^e to the sidi', and rub ifc firmly ; next rub the other in the same way : the faee is .sharpened by holding it firmly in the hand, with the belly upwards, iu a slanting direction ; rub the end rather 512 ENGRAVING. gently on the stone, at an angle of about forty-five degrees, taking care to carry it evenly alon"- until it acquires a very sharp point : this being done, hold the graver a little more upright to squaie the point, which a very few rubbings will eft'ect. The graver lor line work must be slightly turned up, to enable the engraver to run it along the plate ; other- wise the first indentation he makes on the metal would cause his instrument to beconie fixed : the graver for stipple should be slightly turned down, to make dots only. The scraper, which should have three fiutcd sides, is used for taking off the burr left by the action of the needles on the metal. The burnisher is employed to soften lines that have been bltfen in, or engraved too dark, and to polish the plate, or get rid of any scratches, it may accidentally have received. Tlie dabber used to lay the etc/iiuff-f/round 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 much 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 briJijc, 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 when covered with wax. A blind, made of tissue paper stretched upon a frame, ought to be placed between tiie plate and the light, to enable the engraver to see his work on the metal with greater facility and clearness. Ill describing the processes of engraving the various styles enumerated above, little more than a general outline of each method can be given, yet sufficient, it may be pre- sumed, to show the nature of the operation : to narrate all the details that might be in- cluded in the subject would supply matter enough for a small volume. Etchinc) may be classed under two heads : that which is made the initiatory process in line engraving, and that which is known as pai7itcr''s etching. The latter was practised to some extent by very many of the old painters, particularly those of the Dutch school ; and it has also recently come into fashion with many of the artists of our own day, but more for amusement, however, than for any other purpose; in both cases the method of proceed- ing is alike. Etching is the result of a chemical process resulting in corrosion of the metal on which the design has been laid down, or transferred, in the following manner : — The plate must first be covered with a substance already spoken of as ctc/iinf/-ffround, which may be purchased of most of the principal artists' colormen, but many engravers make their own : the annexed receipt has been handed to us by Mr. C. W. Sharpe, who has engraved some of the largest steel-plates published recently, as that which he always uses : — Tarts. Black pitch 1 White wax 1 Burgundy pitch i Asphaltum .-.- 1 Gum mastic --.-------1 Melt the first three ingredients over a slow fire in a pipkin, then add the other two, finely powdered, stirring the whole together all the time ; when well mixed, pour it into warm water, and make it up, while warm, into balls ; if too soft, a little less wax should be used. Care must be taken not to let the mixture burn during the process of making. The etching-ground resists the action of the a(pia fortis. It should be tied up in a piece of strong silk, and applied thus, which is called laying the gromid : — Take the plate firmly in a small hand-vice ; hold it, with the polished face upwards, over a charcoal fire that it may not get smoked, till it is well, but not too much, heated : rub the etching-ground, in the silk, over the plate till it is evenly colored ; the wax, melting with the heat, oozes through the silk. To cftect a more equal distribution of the ground, take the dulbtr and dab the plate gently all over, till it appears of a uniform color ; continue the dabbing till the ]ilate begins to cool, but not longer. The ground is then blackened by being held over the smoke of a candle, or two or three tied together, — wax is far preferable to tallow ; keep the plate in motion, so that every part be made equally dark, and also to avoid injury, bv burning, to the composition ; when cold, the plate is ready to receive the design. To transfer this, a very correct outline of the subject is made with a black-lead pencil on a piece of thin hard paper : fasten the tracing, or drawing, at the top edge, with its face downwards, on to the etching-ground, with a piece of banking-wax, described hereafter, and by passing it through a printing-press — such as is used by plate printers, to whom it should be taken — the drawing is transferred to the ground. The bridge being laid over the plate, the' process of etching may now be commenced ; the points, or needles, which are used to complete the design, remove the ground from the metal wherever they pass, and expose the latter to the action of the acid during the process of what is termed biting in. The needles with the most tapering points should be used for the skies and distances, changing them for others for the foreground, which generally requires broader and deeper lines. Any error ENGRAVING. 513 that has been made may be remedied by covering the part evenly with the etching-ground mollified by spirits of turpentine, using a camel's-huir pencil for the purpose ; and, when dry, the lines may be reiitched througli it. The next operation is that of biting in, performed thus : — A wall or border of bankitig- wax is put round the edge of the plate : this wax, called sometimes lordcring-wax, is made by melting over a slow fire, in a glazed pot, two parts of Burgundy pitch and one of bees- wax, to which is added, when melted, a gill of sweet oil ; when cold it is quite hard, but by immersion in warm water it becomes soft and ductile, and must be applied in this state ; it will adhere to the metal by being firmly pressed down with the hand : the object in thus banking up the plate is to prevent the escape of the acid which is to be applied ; but a spout or gutter nmst be left at one corner to pour oiF the liquid when necessary. Mr. Fielding — to whose work on the art of engraving we are indebted for some of the practical hints here adduced, availing ourselves, however, of the improvements introduced into modern prac- tice — recommends the following mixture as the best : — " Procure some strong nitrous acid, and then mix, in a wide-mouthed bottle, one part of the acid with five parts of water, add- ing to it a small quantity of sal ammoniac, in the proportion of the size of a hazel-nut to one pint of acid, when mixed for biting. The advantage of using the sal ammoniac is, that it has the peculiar property of causing the aqua fortis to bite more directly downwards, and less laterally, by which means lines laid very closely together are less liable to run into each other, nor does the ground so readily break up." When the mixture is cool — for the acid becomes warm when first mixed with water — pour it on the plate, and let it continue there till the more delicate lines are presumed to be corroded to a sufficient depth ; this will prob- ably be in aljout a quarter of an hour ; sweep off the bubbles as they appear on the plate, with a camel's-hair pencil, or a feather ; then pour off the acid through the gutter at the corner, wasli the plate with warm water, and leave it to dry. Next, cover those parts which are sufficiently bitten in with Brunswick black, applying it with a cameFs-hair pencil, and leave it to dry ; again put on the acid, and let it remain twenty minutes or half an hour, to give the next degree of depth required ; and repeat this process of stopping out and biting in, until the requisite depths are all attained : three bitings are generally enough for a painte/s etching. The work is now complete, unless the gravei- is to be used upon it, and the banking-wax may be removed, by slightly warming the margin of the plate ; and, finally, wash the latter with a soft rag dipped in spirits of turpentine, and rubbing it with olive oil. If, when the plate is cleaned, the engraver finds that the acid has acted as he wishes, he hiis secured what is technically termed " a good bite." Steel plates require another method of biting in, on account of their extreme hardness, and liability to rust ; the mode just described is applicable only to copper, the metal gen- erally used by painters for their etchings. For steel plates mix together Tarts. Pyroligncous acid 1 Nitric acid -- 1 Water 3 This mixture should not be allowed to remain on above a minute ; let it be washed off at once, and never use the same water twice ; the plate must be set up on its edge, and dried as quickly as possible to avoid rust : the acid may be strengthened where a stronger tint is required. Rebiting, a process frequently adopted to increase the depth of tint where it is required, or to repair any portion of a plate that has been worn by printing or accidentally injured, is thus performed. The plate must be thoroughly cleaned, all traces of grease removed, by washing it with spirits of turpentine and potass, and polished with whitening ; it is then, when warmed over a charcoal fire or with lighted paper, ready for receiving the ground ; this is laid by using a dabber charged with etching-ground, and carefully dabbing the sur- face ; by this means the surface of the plate only is covered, and the lines already engraved are left clear ; any part of the plate that it may not be necessary to rebite, must be stopped out with Brunswick black, and then the acid may be poured over the whole, as in the first process. Etching on soft ground is a style of engraving formerly much practised in imitation of chalk or pencil drawings ; since the introduction of lithography, however, it has been en- tirely abandoned. The soft ground is made by adding one part of hog's lard to three parts of common or hard etching-ground, unless the weather be very warm, when a smaller quan- tity of lard will suffice ; it should be laid on and smoked in the manner already described. Mr. Fielding gives the following method for working on it : — " Draw the outline of your subject faintly on a piece of smooth thin writing paper, which must be at least an inch larger every way than the plate ; then damp it, and spread it cautiously on the ground, and, .turning the edges over, paste down to the back of the plate ; in a few hours the paper will be dry, and stretched quite smooth. Resting your hand on the bridge, take an 11 or IIB pencil, and draw your subject on the paper exactly as you wish it to be, pressing strongly for the darker touches, and more lightly ibr the delicate parts, and, accordingly as you find Vol. III.— 33 514 ENGEAVING. the {ground more or less soft, which depends on the heat of the weather or the room you work in, use a softer or harder pencil, remembering always that the softer the ground, the softer the pencil " (should be). " When the drawing is finished, lift up the paper carefully from the plate, and wherever you have touched with the pencil, the ground will stick to the paper, leaving the copper more or less exposed. A wall is then put round the margin, the plate bit in, and if too feeble, rebit in the same way as a common etching, using hard etch- ing-ground for the rebite." Line engraving unquestionably occupies the highest place in the category of the ai t ; and, taking it as a whole, it is the most suitable for representing the various objects that constitute a picture. The soft, pulpy, and luminous character of flesh ; the rigid, hard, and metallic character of armor; the graceful folds and undulations of draperies, the twittering, unsteady, and luxuriant foliage of trees, with the bright yet deep-toned color of skies, have by this mode, when practised bj' the best engravers, been more successfully rendered than by any other. The process of line engraving is, first, to etch the plate in the manner already described, and afterward to finish it with the graver and dry-point. An engravcr''s etching differs from a painter''s etching in that every part of the work has an unfinished ap- pearance, though many engravers, especially of landscapes, carry their etchings so far as to make them very effective : engravers of historical and other figure sulijects, generally, do little more than etch the outlines, and the broad shadowed masses, or colors, of the draper- ies ; the flesh being entirely worked in with the burin, or graver: no definite rules can be laid down as to the extent to which the etching should be advanced ere the work of the tool commences, as scarcely two engravers adopt the same plan precisely: much must always depend on the nature of the subject. Neither would it be possible to point out in what jiar- ticular way the graver should be used in the representation of any particular object — this can only be learned in the studio of the master, or by studying the works of the best en- gravers: as a rule it may be simply stated, that in making the incision, or line, the graver is pushed forward in the direction required, and should be held by the handle, at an angle very slightly inclined to the place of the steel or copper plate : the action of the graver is to cut the metal clean out. Within the last few years an instrument, called a ruling machine, has been brought into use for laying in flat tints in skies, buildings, and objects requiring straight, or slightly curved lines ; considerable time is saved to the artist by its use, and more even tints are produced than the most skilful handwork, generally, is able to eflect ; but to counterbalance these advantages, freedom is frequently sacrificed, and in printing a large number of impres- sions, the machine work, unless very skilfully ruled in, is apt to wear, or to become clogged with ink, sooner than that which is graved. Mezzotinto engraving is generally supposed to owe its origin to Colonel Ludwig von Sicgen, an officer in the service of the Landgrave of Hesse ; there is extant a jjortrait by him, in this style, of Amelia, princess of Hesse, dated 1643. Von Siegen is said to have communicated his invention to Prince Rupert, to whom many writers have assigned the credit of originating it. There are several plates executed by the Prince still in existence. It differs from every other style of engraving, both in execution and in the appearance of the impression which the plate yields: a mezzotint engraving resembles a drawing done in washes of color, by means of a camel's-hair pencil, rather than a work executed with any sharp-pointed instrument : but a pure mezzotint engraving is rarely produced in the prci-ent day, even for portraits : the advantages derived from combining line and stipple, of which we shall speak presently, with it, to express the different kinds of texture in objects, have been rendered so obvious as almost to make them necessary: this combination is termed the mired nfgle. The distinguishing excellencies of mezzotint are the rich depth of its shadows, an exquisite softness, and the harmonious blending of light and shade: on the other hand, its great defect is the extreme coldness of the high lights, especially where they occur in broad masses. The instruments used for this kind of work arc, burnishers, scrapers, shading tools, ron- leftes, and a cradle, or rocking tool. The burnisher and scraper differ in form from those already described: the roulette is used to darken any part which may have been scraped away too much; it ought to be of different sizes: the cradle is of the same form as the shading tool, and is used for the purpose of laying ground.s. Tlie operation of engraving in mezzotint is precisely the opposite of that adopted in all otlier styles : the processes in the latter are from light to dark, in the former from dark to liglit, and is thus effected : A plate of steel or copper is indented all over its face by the cradle, an instrument which somewhat resembles a chisel with a toothed or serrated edge, by which a burr is raised on every part in such quantities that if filled in with ink, and printed, the impression would exhibit a uniform mass of deep l)lack : this operation is called laijitig the ground ; it is performed by rocking the cradle to and fro, and the directions, or leai/s, as the engravers call them, are determined by a plan, or scale, that enables the engraver to pass over the plate in almost any number of directions Avithout repeating any one of them. When an outline of the subject has been first etched in the ordinary way be- ENGRAVING. 515 fore the ground 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 alter this manner till the work is finished ; the deepest shades are produced from the ground that is left untouched. There is, however, no style of engraving lor 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 tlie etchhig-ground, and the sulyect 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 arc afterwards etched in dots larger and laid closer together. Tiie work is then bitten in with the acid ; and the ground being taken olf, tlie 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 drawings 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 expressing the same kind of work. Aquatint engraving, which represents a drawing in Indian-ink or bistre even more than does mezzotint, 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. This being the case, and as any detailed description of the mode of working would, to be of any service, occupy a very considerable space, it will, doubtless, be deemed sufficient to give 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 is 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 dark 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 u))on 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 Ijy a printer's inking-roller, an o]HMation 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 stuft" like blanketing. These are moved along the table to the spot where the two rollers meet; and the u])|)er one being turned by the hanillc fixed to the fly-wheel, the plate passes through it, conveying the im- pression as it moves; the print is then taken olf the plate, which has to undergo the sanu> process of inking for the next and every succeeding imjuession. The proofs of an engraved plate are always taken by the most skilful worknu'u in a ])rinting establi.'fhment ; in the priuci[)al houses there are generally erajjloycd from two to six men, aocordingto the 516 ENGRAVING. amount of business transacted, whose duty it is to print proof impressions only ; they are called provers. A careful, steady workman is not able to print more than from 180 to liOO 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 houis ; the prover, from the extreme care required in inking the plate, and from the extia time 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, even in the least degree, and that very few proofs, comp*ed with the ordinaiy prints, are generally struck oil", is the reason ^hy they are sold at a price so much greater than the latter. Notwithstanding the vast multiplication of engravings witliin the last few years, it ia 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 cngiavings of such subjects a popularity that lias 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, biu their talents are not called into reciuisition 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 wiiich the public cannot apiMCciate, 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 imprcs.sions which it yields, a copper-plate will seldom produce more than 500 or 600 good prints ; we have known a steel, witli occasionally retouching, produce more than S0,000, 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 tiadesman in a small but respectable Avay 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 infoimed 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. Ue thus descril)cs 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 m 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, beiug combined with the hydrochlorate of ammonia of the solution, will become a bichloride of ammonia and iron ; ou a copper-plate being placed at the opposite i)ole 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. ENGRAVING ON WOOD. 517 " My invention 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 chemical 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 a 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, but 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 arrangement. 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 trough, 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 iron, 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. EXGRAVIX(; O.V "wood. In order to make the whole process of wood engraving clear to the reader, we will describe the production of a wood-ctit 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, J 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 pres.sure ; 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 tlie cut is executed if the wood is too green. The slice is ultimately trinnned 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 .'^pace of tiin«^ by putting the various pieces into different engravers' hands, and then screwing the whole to- gether. The iipper surface of the wood is carefully prejiarcd so that no ine(|ualities may appear npon it, and it is then consigned to the draughtsnian to receive the drawing. lie covers the surface with a light coat of flake white mixed with weak gum-water, and the 518 ENVELOPES. 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 engraver's hand?, or deceive him as to the depth of the line he is cutting in the wood. The old drawings of the era of Durer seem to have been carefully drawn with ])en and ink on the wood ; but the modern drawing being very finely drawn with the jiencil or silver point is obliterated easily, and there is no mode of "setting" or sectiring it. To ol)viate 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 eficct ; in damp and wintry weather he sometimes wears a shade over the mouth to hinder the ^eath 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 consef|uently 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 rcengraved. 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 objiteiate 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 tfeep 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 ajipcar 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 douljle brilliancy. When careful printing is bestowed on cuts, it is sometimes usual to insure this good eilect, 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 clahoiately-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 illu.stration in constant demand, the creative power of one single genius — Thomas Bewick — shines forth in greater vigor than ever. — ¥. W. F. ENVELOPES. The manufacture of envelopes has so largely increased, that the old method of folding them by means of a '■'•bone foldiiiff-xtick,^' although a good workman could thus produce 3,0(i0 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 Rue & Co., each piece of jiaper, 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 1)0X, 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 pre.s.^er 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 cm-ved arm, and the sides thereof to the inner portion of the arm ; so that the ends and sides of the ])resser 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 lap[)et 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 lajjpet presses down the third flap of the envelo{)e upon the two cemented flaps, and thereby causes it to adhere thereto ; and then a pressing-piece, of the same size as the fini.shed en- veldfic, foMs over the last flap and presses the whole flat. The final operation is to remove the envelope, and this is effected l)y a pair of metal fingers, with india-iubber ends, which descend upon the enveloi)e, and, moving sideways, diaw 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-movhig endless band, which gradually carries ETHER. 519 the finished envelopes away. A fresh piece of paper is laid upon the box or frame, and the above operations 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 suitable exhausting apparatus, and the paper is thereby caused to adhere to it at the holes in its under surface by the pressure of the atmosphere. The instrument carries the paper over a rectangular recess or box ; and then, the vacuum within it being destroyed, it de- posits the paper between four pins, fixed at the angles of the box, and returns for another piece 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 angular feeders, communicating with a reservoir of cement or adhesive matter, and thereby becomes 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 frame 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 below ; the feeding instrument then brings forward another piece of paper ; and a repetition of the above movements takes place. EllEMACAUSIS, — slow combustion. This term has been applied to that constant com- bination of oxygen with 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 combu-stion. ETHER, G^lPO. Sipi. Sulphuric ether, Oxide of cthyle, 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 07i 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 i)ro- ceeding is to have a large stone bottle with a tul)ulature 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 tlie end, near the retort or still, a beiul downwards leading into the tubulature. If a glass still be used it must for safety be placed in a sand bath. The distillate obtained, cither on the largo or small scale, is never pure ether, Ijut contains sulphurous and acetic acids, bosiWes water and alcohol. To remove those, 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 water, to remove which it .should be rectified in a water bath. The fluid will then constitute the ether of conuuorce. If the second distilla- tion be pushed too far the ether will, if evaporated on tlu; hand, leave an unpleasant after smell, characteristic of impure ether. If wished exceedingly pure, it must be shaken up in 520 EXOSMOSE and ENDOSMOSE. the separating globe, with pure water. This will dissolve the alcohol and leave the ether, contaminated only by a little water, which may be removed by digestion with quicklime and redistillation at a veiy low temperature on a hot water bath. Pure ether is a colorless mobile liquid, sp. gr. 0.71. 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 generic term to express a body derived from an alcohol by the elimination of water. Many chemists write the formula C'lPO, and call it oxide of ethyle in the same manner as they regard alcohol as tlio hydrated oxide of tiie same radical. But there is no just reason for departing from the hiw we have laid down with reference to the formulae of organic compounds. (See Cnssi- iCAL FoRMUL*.) We shall therefore write ether CH^'O". This view has many advan- tages. We regard, with (rerhardt and Williamson, ether and alcohol as derived from the type water. Alcohol is two atoms of water in which one equivalent of hydrogen is replaced by ethyle ; ether is two atoms of water in which both atoms of hydrogen are replaced by tliat radical. But there is a large cla.ss of compound ethers procurable by a variety of processes. These ethers were long regarde, c, and all the lodes and the Elvan course moved. In this case the move- ment has probably taken place from the North towards the South. This disturbance will be continued to a great depth, and in Jit/. 289 is a section showing the dislocation of a lode into three parts. In this case the movement has probably been the subsidence of that portion of the ground containing the lode b, and the further subsidence of that portion containing the lode a ; the condition of the surface being subsequently altered by denudation. The in- clination of a lode is frequently changed by these movements: thus fig. 291 supposes c d to represent the original condition of the lode ; by a convulsion, the portion a b has fallen away, leaving a chasm between, and tlie " dip" or inclination of the lode is therefore materially changed. The direction of the lode is frequently altered by these movements. Many lodes in Cornwall have a direction from the N. of E. to the S. of W. up to a fault, on the other side of which the direction is changed from the S. of E. to the N. of W. Where these dis- turbances are of frequent occumence, the difficulties of mining are greatly increased. FERMENTATIOX. {Fermentation, Fr. ; Gahrumj, Germ.) A change which takes place, under the influences of air and moisture at a certain temperature, in the constituent particles of either vegetable or animal substances. This change is indicated by a sensible internal motion — the development of heat — the evolution of gaseous products. Fermenta- tiQn may be divided into several kinds, as — Saccharine, Butyric, Acetic, Glyceric, Alcoholic or Vinous, Lactic, Putrefactive, Mucous. Of the latter examples but a brief notice is required. Mucorta fermentation is established when the juice of the beetroot or carrot is kept at a temperature of 100° for some time, when a tumultuous decomposition takes place. All the sugar disappears, and the liquor is found to contain a large quantity of gum, and of mannite with lactic acid. Lactic Fermentation. — If a solution of one part of sugar in five parts of water be made to ferment, by the addition of a small quantity of cheese or animal membrane, at a tem- ])erature of 90° or 100°, lactic acid is formed, which may be separated by adding a little chalk, the lactate of lime depositing in crystalline grains. In lactic fermentation mannite invariably is produced as a secondary product, the formation of which is not explained. It has been suggested that the formation of mannite is connected with the production of suc- cinic acid, which Schmidt, in a letter to Liebig, states that he has found iu fennenting liquids containing sugar. He suggests the following formula : CIPO" + CUPO^ = C"H'-0" Mannite. Succinic acid. Grape sugar. Glyceric Fermentation. — When glycerine is mixed with yea.st, and kept in a warm place for some weeks, it is decomposed and converted into metacetonic acid. This fci- montation resembles the last named. The glycerine, C^H'O', forming metacetonic acid, CHV'O*, as sugar, C'TPO", does lactic acid, C^IPO*, by loss of the elements of water. — Kane, Butyric Fermentation. — If the lactic fermentation is allowed to proceed beyond the point indicated for the formation of lactate of lime, the precipitate in part redissolves with a very copious evolution of hydrogen gas and carbonic acid, and the liquor contains buty- rate of lime. In this action two atoms of lactic acid, C"ir"0'", produce butyric acid, CirO*, carbonic acid, and hydrogen gas. Putrefactive Fermentation. See Pt'TKEFACTiON. The three first named kinds of fermentation demand a more especial attention from their importance as processes of manufacture. Under the heads respectively — Acetic Acid, Beer, Brewing, Distillation, Malt, and Wine, will be found everything connected with FERMENTATION. 523 the practical part of the subject ; we have therefore only now to deal with the chemical and physical phenomena which are involved in the remarkable changes which take place. When vegetable substances are in contact with air and moisture, they undergo a peculiar change, (decomposition.) Oxygen is absorbed, and carbonic acid and water are given off, while there is a considerable development of heat. This may take place with greater or less rapidity, and thus ercmacausis, fermentation, or combustion may be the result ; the spontaneous ignition of hay (as an example) being the final action of this absorption of oxygen. Saccharine Fermentation. — If starch, C'^H^O" + 2H0, be moistened with an infusion of pale malt, it is rapidly converted into dextrine, C^Il'^O'", and hence into grape sugar, C'*H"0" ; this is especially called the saccharine fermentation, since sugar is the result. Acetic and Alcoholic Fermentation. — If sugar is dissolved in water, it will remain per- fectly unaltered if the air is excluded ; but if exposed to the air, a gradual decomposition is brought about, and tlie solution becomes brown and sour. Oxygen has been absorbed, and acetic acid produced. If, however, the sugar is brought into contact with any organic body which is in this state of change, the particles of the sugar participate in the process, car- bonic acid is evolved, and alcohol produced. There are some substances which are more active than others in producing this change. Yeast is the most remarkable ; but blood, white of egg, glue, and flesh, if they have begun to putrefy, are capable of exciting fermen- tation; vegetable albumen and gluten being, however, more active. Vegetable albumen, gluten, and legumin differ from most vegetable bodies in the large quantity of nitrogen which they contain. These substances exist in all fruits, and hence, when fruit is crushed, the sugar of the juices in contact with the albumen or gluten being then exposed to the air, oxygen is rapidly absorbed, the nitrogenous body begins to putrefy, and the sugar passe-a into fermentative activity. The necessity for oxygen is at the commencement of the decomposition ; when the putrefaction of the albumen or gluten has once begun, it extends tliroughout the mass without requiring any further action of the air. These may be regarded as natural ferments. Yeast is an artificial one. This body will be more particularly described. See Yeast. To produce a vinous liquid, it is necessary that there shall be present sugar, or some body, as starch or gum capable of conversion into sugar, a certain portion of water, and some ferment — for all practical purposes yeast; and the temperature should be steadily maintained at about 80° F. Both cane and grape sugar yield alcohol by fermentation, but Liebig considers that cane sugar, before it undergoes vinous fermentation, is converted into grape sugar by contact with the ferment : and that, consequently, it is grape sugar alone which yields alcohol and carbonic acid. Grape sugar, as dried at 212^, contains exactlv the elements of two atoms of alcohol and four of carbonic acid. As 2(Cni'0-) and 4C0' "arise from C"H'-0'^ Cane sugar takes an atom of water to form grape sugar. It follows therefore that cane sugar should in fermenting yield more than its own weight of carbonic acid and alcohol ; and it has been ascertained by experiment that 100 parts actually give 10-1, whilst by theory 105 should be produced, consisting of 51.3 of carbonic acid, and 53.7 of alcohol. — (Kane.) Dr. Pereira has given the following very intelligible arrangement to exhibit these changes : — PEEIAL. COMPOSITION. 4 oq. carbonic acid - - S3 eq. alcohol - 92 180 ISO 180 "iSO 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 decom])osition which, caused by external influences in any part of an organic compound, proceeds througli the entire mass without the further coiipcration of the original cause. Ferjnentation, according to Liebig's definition, is the decomposition exliibited in the presence of putrefying substances or ferments, by compounds nitrogenous or non-nitrogenous, wliich alone are notcapul)lo of putrefiiction. He distinguishes, in both putrefaction and fermentation, processes in wliicli the oxygen of the atmosphere continually coiiperates, 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 MATERIAL. COMPOSITION. 1 equivalent of crystallized cane susar - - 171 1 equivalent of water - - 9 , 1 eq of >■ srapo sugar ISO ' 4 cq. carbon 24 1 8 " carbon 4S I 8 " oxygen 04 1 4 " oxvgcn S2 . 12 " hydrog. 12 624 FERMENTATION. adduces that no trace of vegetal formations are perceptible in milk which is left for Bomo time in vessels carefully tied over with blotting paper, not even after 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 observed too exclusively, the phenomena have been generalized, while the explanation of this process ought to bo derived rather from the study of fermentative phenomena of a more general character. Blondcau propoimds 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 which he designates Torvula ccrevisice ; 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 undeigone 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 cercvixur^ and of Pcnicillmm glancmn ; 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 i'ermentation is due to the development of Torvula acdi ; 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 l)y the term fatty fermentation, (fermentation adipense,) is caused by Penicilliitm fflaucam or Torrida viridis ; and the former fungus is stated to act like- wise in butyric arid in urea fermentation, (conversion of the urea into a caibonate 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 Brendccke, (particularly in reference to the statement that fei menta- tion taking place in a solution of sugar in contact with porous bodies is due to an inqnuitj of sugar;) according to which various porous bodies, such as charcoal, paper, flowers of stdphur, &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 poious 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 fciment. Both oxygen and caibonic 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 electiical 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 communioated the results of his experiments to the Avnale Chem. Pharm. After stating numerous experiments, he continues : "Nor aie fungi ihc prhmim vwrenF; of saccharic fermentation ; the clear filtrate obtained by throwing almonds crushed in water upon a moist filter, soon induces fcrm.cntation 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 R^rmentation is fully developed. If tke 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 lajiidly ceases; hence the growth of fungi during fermentative processes is but a secondary phenomenon. The in- crease of the residuary ferment, which occurs after jTast 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. per barrel upon beer of which " the worts used before fermexta- tion were not of less specific gravity than TOSl." The brewer observes the original gravity of his worts by means of some foi-m 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 orifinal gravity. From the great uncertainty which appeared to attend this question. Professors Graham, Ilofmann, and Redwood were employed by the Board of Inland Revenue to dis- cover how the original gravity of the beer might be ascertained most accurately from the properties of tlie beer itself. When worts are fermented, the sugar passes into alcohol and they lose in density, and assume as beer a difterent specific gravity. The gravity of the wort is called the original gravitij — 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 of 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 tlie 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 oft"; by the boiling point of the beer, which 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 beer. " 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 oi' sugar solutions, constructed by Mr. Bate, have been verified, and are considered entirely trustworthy. The numbers in the first and third columns of Table I., which follows, a'C 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, which 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 oi" 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 8S parts of oxygen; or of 72 parts of carbon combined with 5)9 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 whicli sugar undergoes dui-ing 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. 526 FERMENTATION. ■ Table I. — Specific gravity of solutions of Cane Sugar in water. 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-t53 1051 _ 150 63-16 1061-8 175 73-68 1072-0 200 84-21 1083-8 225 94-73 1095-2 250 105-20 1106-7 ■ " When j'east 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 fail, owing to the escape of carbonic acid gas, and the formation of alcohol, which is specifically lighter than water; 171 grains of sugar, together with 9 grains of water, being converted into 92 grains of alcohol and 88 grains of carbonic acid, (C'-II"0" + IIO = 2C^H''0^ + 4 CO".) But if the process of fermentation be closely watched, the fall of gravity in cane sugar will 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 Vaoo of the weight of the sugar, the gravity of the sugar solu- tion rose gradually in four days from 1055 to 1057-91, 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 II. Rose 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 10o4-7; and being afterwards heated for twenty-three hours to a temperature not exceeding 128° Fahr., it was found (when cooled) to have attained a giavity of 1057-63 — ^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 staich sugar, and solutions containing an equal quantity of carbon exhibited the following gravities : — Cane sugar - 1072-9. Tale malt - 1074-2. 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 wliich the following results have been deduced : — Starch sugar, Dextrin, Caramel, 1076 1060-9 1062-3 Caramel is stated to interfere more than dextrin in giving lightness or apparent attenua- tion to fermented worts, without a corresponding production of alcohol. " Another constituent of malt wort, which should not be omitted, is the soluble azotizcd 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. Tlic 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 FEKMENTATION. 527 1003-1. Hence a loss of density has occurred during fermentation of I'l degree on a wort of 1088 original gravity, which can be referred to a change in the proportion of albuminous matter. It will 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 evaporated to dryness, and the solid i-esidue 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 (juantity of the beer, such as four fluid ounces, and boiling it down to somewhat less than half its bulk in an 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 specific gravity of thi:: 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 the history was known, the original gravity of the malt wort was 1121, or 121° ; the specific gravity of the beer itself before evaporation, 1043 : and the extract gravity of the beer 1056-7, 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 wlien filled 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 1)eer, 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, 56-7°. " 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 li(juor. 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 much 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 substance 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 lif[uids 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 becomes 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 lOJ gallons of solution, of which the specific gravity was lOoo'S at 60° ; and after adding three fluid jjounds of fresh porter yeast, the specific gravity was 1055-95. The original gravity may be taken as 1055-3 '^55-3°.) 528 FEKMENTATION. 'Table II. — Fermentation of Sugar Wort of original gravity 1055*3. I. II. m. IV. V. Number of Period of Degrees of Spirit Degrees of Extract Degrees of Extract Observation. Fermentation. Indication. Gravity. Gravity lost. Days. Hours. 1 U 55-30 0- 2 6 1-59 52-12 S-18 3 12 2-57 47-82 7-48 4 19 3-60 43-62 11-68 5 23 4-33 40-13 1517 6 1 5 5-31 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 85-04 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 51-15 " 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, ana 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 it.) 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 2 3 4 5 6 1-71 4-74 9-26 13-48 18-30 22-54 7 8 9 10 11 27-01 31-87 3712 42-55 47-88 "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 IV., 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 mav 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 ir. The latter marks, according to the table, 47-7° of gravity lost, which added to the observed extract gravity, 7-9°, gives 55-6° of original gravity for the beer, (1055-6.)" •Similar tables are constructed for starch sugar, and for various worts with and without hops. 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 of gravity lost corresponding to tentlas of a degree of spirit indication are added from calculation. Degrees of Spirit •0 •1 •2 •3 •4 •5 •6 •7 •8 •9 Indication. •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 2 5-0 5-4 5-8 6-2 6-6 7-0 7-5 8-0 8-5 9-0 3 9-5 9-9 10-3 10-7 11-2 11-6 12-0 12-4 12-8 13-3 4 13-8 14-2 14-6 15-0 15-0 15-9 16-3 16-7 17-2 17-7 6 18-3 18-7 19-1 19-5 199 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 25-6 261 26-6 7 27-1 27-6 28-1 28-6 29-1 29-6 30-0 30-5 31-0 31-5 8 82-0 32-5 33-0 33-5 34-0 34-5 35-0 35-5 36-0 36-6 9 37-2 37-7 38-2 38-7 39-2 39-7 40-3 40-8 41-3 41-8 10 42-4 42-9 43-4 44-0 44-0 45-0 45-6 46-1 46-6 47-2 11 47-7 After explaining 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 number. " The data in a particular beer were as follows : — Extract gravity, Beer gravity, Spirit indication, 1044-7 1035-1 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 1044-7, the extract gravity of the same beer, 1087-7 is obtained as the original gravity of the beer." The results of the extensive series of experiments made, were, that tlie 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 soUd 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.— 34 530 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 alcohol 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 entirely ceased, heat was applied to the retort to distil off" the alcohol, which was collected in a cooled re- ceiver. About three-fifths of the liquid were distilled over for this purpose; and the vol- ume of the distillate was then made up with water to the original volume of the beer. The specific gravity of the last spirituous liquid was now taken by the weighing-bottle. To ob- tain a correction for the small quantity of alcohol unavoidably introduced by the yeast, a parallel experiment was made with that substance. The same weight of yeast was mixed with water, and distilled in another similar retort. The volume of this second distillate was also made up by water to the beer volume ; its specific gravity observed, and deducted from that of the preceding spirituous liquid. This alcoKol was added to that obtained in the first distillation of the beer, and the weight of starch sugar corresponding to the whole amount of alcohol was calculated. This was the first result. " For the solid matter of the beer : the spiritless liquid remaining in the retort was made up with water to the beer volume, and the specific gravity observed. A correction was also required here for the yeast, which is obtained by making up the water and yeast distilled in the second retort, to the original volume of the beer, and deducting the gravity of tliis fluid from the other. The quantity of starch sugar corresponding to this corrected gravity of the extractive matter was now furnished by the table. This was the second result. • " The two quantities of starch sugar thus obtained were added together. The specific gravity of the solution of the whole amount of starch sugar, as found iu the table, repre- sented the original gravity of the beer. " This method must give an original gravity slightly higher than the truth, owing to the circumstance that the dextrin, albumen, and salts, which are found among the solid matters dissolved in beer, are treated as having the low gravity of extractive matter, and accordingly amplified by about one-sixth, like that substance, in allowing for them ulti- mately as starch sugar. The error from this source, however, is inconsiderable. It is to be further observed, that the error from imperfect manipulation, of which there is most risk in the process, is leaving a little sugar in the extractive matter from incomplete fer- mentation. This accident also increases the original gravity deduced. The process has given results which are remarkably uniform, and is valuable in the scientific investigation of the subject, although not of that ready and easy execution which is necessary for ordinary practice, and which recommends the former method." " Table V. — To be used in ascertaining Original Gravities by the Distillation Process. Degrees of Spirit Indication with correspondi7\g degrees of gravitij lost in Malt Worts. Degrees of Spirit Indication. •0 •1 •2 •3 •4 •5 •6 •7 •8 •9 • o •G •9 1-2 1-5 1-8 2-1 2-4 2-7 1 3-0 3-3 3-7 4-1 4-4 4-8 5-1 5-5 5-9 6-2 2 6-G 7-0 7-4 7-8 8-2 8-6 9-0 9-4 9-8 10-2 3 10-7 111 11-5 12-0 12-4 12-9 13-3 13-8 14-2 14-7 4 15-1 15-5 16-0 16-4 16-8 17-3 17-7 18-2 18-6 19-1 5 19-5 19-9 20-4 20-9 21-3 21-8 22'2 22-7 231 23-6 6 24-1 24-G 25-0 25-5 26-0 26-4 26-9 27-4 27-8 28-3 n 28-8 29-2 29-7 30-2 30*7 31-2 31-7 32-2 32-7 33-2 8 33-7 343 34-8 35-4 35-9 3G-5 37-0 37-5 38-0 38-6 9 39-1 39-7 40-2 40-7 41-2 41-7 42-2 42-7 43-2 43-7 10 44-2 44-7 451 45-6 46-0 46-5 47-0 47-5 48-0 48-5 11 49-0 49-6 501 50-6 61-2 51-7 52-2 62-7 53-3 53-8 12 54-3 54-9 55-4 55-9 56-4 56-9 57-4 57-9 58-4 58-9 13 59-4 60-0 60-5 61-1 61-6 62-2 62-7 63-3 63-8 64-3 U 64-8 65-4 65-9 66-5 67-1 67-6 68-2 68-7 69-3 69-9 15 70-5 FERROCYANIDES. 531 " Table VI. — To be used in ascertaining Original Gravities by the Evaporation Process. Degrees of Spirit Indication with corresponding degrees of gravity lost in Malt Worts. Desrees of Spirit •0 •1 •2 •3 •4 •0 •6 •7 •8 •9 Indication. __ •3 •7 1-0 1-4 1-7 2-1 2 4 2-8 3-1 1 3-5 3-8 4-2 4-6 5-0 5-4 5-8 6-2 6-6 7-0 2 7-4 7-8 8-2 8-7 91 9-5 9-9 10-3 10-7 11-1 3 11-5 11-9 12-4 12-8 13-2 13-6 14-0 14-4 14-8 15-3 4 15-8 16-2 16-6 17-0 17-4 17-9 18-4 18-8 19-3 19-8 5 20-3 20-7 21-2 21-6 22-1 22-5 23-0 23-4 23-9 24-3 6 24-8 25-2 25-6 26-1 26-6 27-0 27-0 28-0 28-5 29-0 7 29-5 30-0 30-4 30-9 31-3 31-8 32-3 32-8 33-3 33-8 8 34-3 34-9 35-5 36-0 36-6 37-1 37-7 38-3 38-8 39-4 9 40-0 40-5 41-0 41-5 42-0 42-5 43-0 43-5 44-0 44-4 10 44-9 45-4 46-0 46-5 47-1 47-6 48-2 48-7 49-3 49-8 • 11 50-3 50-9 51-4 51-9 52-5 53-0 53-5 54-0 54-5 55-0 12 55-6 56-2 56-7 57-3 57-8 58-3 58-9 59-4 69-9 60-5 13 61-0 61-6 62-1 62-7 63-2 63-8 64-3 64-9 65-4 66-0 14 66-5 67-0 67-6 68-1 63-7 69-2 69-8 70-4 70-9 71-4 15 72-0 FERROCYANIDES. The compounds of the radical ferrocyanogen. The latter radical is bibasic ; when, therefore, it combines with hydrogen to form ferrocyanic acid, it takes up two atoms. Thesft two atoms of hydrogen can be replaced by metals as in ferrocyanide of potassium or prussiate of potash, as it is commonly called. See Prcssiate of Potash. Ferrocyanogen consists of C^N^Fe, which may also be written Cy'Fe, or, for brevity's sake, Cfy. The modes of preparing the ferrocyanides differ, according as the resulting substance is soluble or insoluble in water. The soluble salts, such as those with alkalies, are prepared either by neutralizing hydroferrocyanic acid with the proper metallic oxide, or by boiling Prussian blue with the oxide, the metal of which it is intended to combine with the fer- rocyanogen. Other methods may also be adopted in special cases. The processes for pre- paring the ferrocyanides of the alkali metals on the large scale will be described iu the arti- cle Prussiate of Potash. When the ferrocyanide is insoluble in water, it may be prepared by precipitating a salt of the metal with ferrocyanide of potassium. Thus, in the preparation of the reddish or purple ferrocyanide of copper, 2(CuO,SO=) + K^'Cfy =r Cu'Cfy + 2(K0,S0'). The above equation written in full becomes : — 2(CuO,SO=) + K'C'N^Fe = Cu^C'N^Fe + 2(K0,S0'). Ferrocyanide of potassium is much used as a test for various metals, in consequence of the characteristic colors of the precipitates formed with many of them. The principal ferro- cyanides with their colors and modes of preparation will be found in the following list: — Ferrocyanide of aluminium. — An instable compound formed by digesting hydrate of alumina with ferroprussic acid. Ferrocyanides of antimony and arsenic. — Neither of these salts are known in a state of purity. Ferrocyanide of barium. — This salt may be prepared by boiling prussian blue in slight excess with baryta water and evaporating to crystallization. Ferrocyanide of bismuth. — When a solution of ferrocyanide of potassium is added to a solution of a salt of bismuth, a yellow precipitate is obtained. It becomes of a greenish tint on keeping for some time. Ferrocyanide of cadmium may be attained as a white precipitate on adding a solution of ferrocyanide of potassium to a soluble salt of cadmium. Ferrocyanide of calcium may be prepared in the same manner as that of barium, but, owing to the sparing solubility of lime in water, we must substitute cream of lime for baryta water. Ferrocyanide of cerium is a white salt only slightly soluble in water. Its properties are very imperfectly known. Ferrocyanide of chromium. — The protochloride of chromium gives a yellow precipitate with ferrocyanide of potassium. Ferrocyanide of cobalt. — Salts of cobalt give a pale blue precipitate with ferrocyanide of potassium. It appears to decompose on keeping, as its color becomes altered. Ferrocyanide of copper. — When ferrocyanide of potassium is added to a solution of subchloride of copper, a white precipitate appears, which, on exposure, becomes converted 532 FILTRATION. into a purplish red substance, apparently identical -with the ordinary ferrocyanide of copper which falls down on the admixture of salts of the protoxide of copper with solutions of ferrocyanide of potassium. Ferroci/anide of glucimnn may be obtained, according to Berzelius, under the form of an amorphous varnish, by decomposing ferrocyanide of lead with a solution of subsulphate of glucina. Ferrocyanide of hydrogen constitutes ferroprussic acid. Frrrocyavide of iron, or prussian blue. — This salt exists in several conditions, accord- ing to the mode of preparation. The ordinary salt is formed by adding a solution of fer- rocyanide of potassium to a solution of a persalt of iron. The following equation explains the reaction that ensues with the sesquichloride : — 2(Fe''CP) -H 3(CfyK-) = 3(CfyFe^) + 6KC1. Ferrocyanide of lead is procured as a white precipitate by adding a solution of fer- rocyanide of potassium to a salt of lead. Ferrocyanide of magnesium is probably best prepared by neutralizing ferroprussic acid with magnesia or its carbonate. It forms a pale yellow salt. Ferrocyanide of manganese may be obtained as a white precipitate, on adding ferro- cyanide of potassium to a solution of pure protochloride or protosulphate of manganese. . Ferrocyanide of mercury. — This compound cannot be obtained in a state of purity by precipitation. It has not been sufficiently examined. Ferrocyanides of molybdenum. — Molybdous salts give, with ferrocyanide of potassium, a dark brown precipitate soluble in excess of the precipitant. If a salt of molybdic oxide be treated in the same manner, a precipitate is obtained, having a similar appearance, but insoluble in excess. Molybdates in solution give precipitates lighter in color than the last. Ferrocyanide of nickel is obtained under the form of a pale apple green precipitate, on addition of prussiate of potash to a salt of nickel. Ferrocya7iide of silver. — Ferrocyanide of potassium gives a white precipitate with sil- ver salts. Ferrocyanide of sodium may be formed by the action of caustic soda on prussian blue. Ferrocyanide of strontium can be procured precisely in the same manner as the cor- responding barium salt, substituting solution of caustic strontia (obtained from the nitrate by ignition) for baryta water. Fen-ocyanide of tantalum has probably never been obtained pure. Wollastou found that tantalic acid (dissolved in biuoxolate of potash) gave a yellow precipitate with prussiate of potash. Ferrocyanide of thorium. — A white precipitate is produced by the action of solution of prussiate of potash on salts of thorium. Ferrocyanide of tin.—VwTQ salts of tin, whether of the per- or prot-oxide, give white precipitates with ferrocyanide of potassium. Ferrocyanides of titanium. — Solutions of titanates give a golden brown precipitate when treated with solution of ferrocyanide of potassium. Ferrocyanides of vranium. — The protochloride gives a pale, and the perchloride a dark reddish brown precipitate with ferrocyanide of potassium. Ferrocyanide of vanadium. — Salts of vanadic oxide give pale yellow, and of vanadic acid, rich green precipitates with prussiate of potash. Ferrocyanide of yttrium. — Chloride of yttrium gives a white precipitate with ferro- cyanide of potassium. Ferrocyanide of zinc cannot be prepared by precipitation. It may be obtained in the form of a white powder by the action of oxide or carbonate of zinc on ferroprussic acid. — C. G. "W. For Feruo-Cyanogex, see Ure's Dictionary of Chemistry. FILTRATIOX. Mr. H. M. Witt communicated to the Philosophical Magazine for De- cember, 1856, an account of some experiments on filtration, which are of much value. Many of his experiments were made at the Chelsea Water Works, and they appear of such interest that we quote the author's remarks to some extent. " The system of purification adopted by the Chelsea Water Works, at their works at Chelsea, consisted hitherto (for the supply has by this time commenced from Kingston) in pumping the water up out of the river into subsiding reservoirs, where it remained for six hours ; it was then allowed to run on to the filter-beds. These are large square beds of sand and gravel, each exposing a filtering surface of about 270 square feet, and the water passes through them at the rate of about GJ gallons per square foot of filtering surface per hour, making a total quantity of 1C87.5 gallons per hour through each filter. " The filters are composed of the following strata, in a descending order: — ft in. 1. Fine sand 2 6 2. Coarser sand - - 1 3. Shells 6 4. Fine gravel 3 5. Coarse gravel 3 3 ' FILTRATION. 533 These several layers of filtering materials are not placed perfectly flat, but are disposed in waves ; and below the convex curve of each undulation is placed a porous earthenware pipe, which conducts the filtered water into the mains for distribution. The depth of water over the sand was 4 feet 6 inches. The upper layer of sand is renewed about every six months, but the body of the filter has been in use for about twenty years. " Samples of water were taken and submitted to examination : — '* 1st, from the reservoir into which the water was at the time being pumped from the middle of the river. " 2d, from the cistern, after subsidence and filtration." Experiments were made at different seasons of the year ; but one of Mr. Witt's tables will sutficiently show the results. 1. Shows the quantities of the several substances originally present, represented in grains, in the imperial gallon (70,000 grains) of water 2. The amount present after filtration. 3. The actual quantities separated in grains in the gallon of water. 4. The percentage ratio which the amounts separated bear to the quantities originally present. 1. Originally present. 2. After filtration. 3. Amount separated. 4. Percentage ratio of separated Matter. Total solid residue, includ- ing suspended matter - Organic matter Total mineral matter Suspended matter - Total dissolved salts Lime . - . - 65-60 4-05 51-55 28-93 22-62 8-719 22-85 1-349 21-501 2-285 19-216 8-426 32-76 2-70 30-049 26-645 3-404 0-293 58-90 66-66 58-29 92-10 15-04 3-36 " It has been assumed as a principle that sand filtration can only remove bodies me- chanically suspended in water, but I am not aware that this statement has been estab- lished by experiment ; in fact, I am not acquainted with any published analytical examina- tion of the effects of sand filtration. " These experiments supply the deficiency, and show, moreover, that these porous media are not only capable of removing suspended matter, (80 to 92 per cent.,) but even of sepa- rating a certain appreciable quantity of the salts from solution in water, viz., from 5 to 15 per cent, of the amount originally present, 9 to 19 per cent, of the common salt, 3 per cent, of the lime, and 5 of the sulphuric acid. "Taking the purer water from Kingston, two experiments were made simultaneously with the same water, one filtration being through charcoal alone, and the other through sand alone, the sand filter having an area of 4 square feet, and consisting of the following materials : — ft. in. Fine sand -- 19 Shells 1^ Gravel -- l^ Coarse gravel 9 Results of Sand Filtration. 2 9 Original Water lued. After 23 hours' action. After 120 hours' action. Compnrison. Amount separated. Percentage of Quantity separated. Comparison. Amount separated. Percentage ratio of Quantity BeparatCil. Total residue Mineral salts Organic matter - Suspended matter ,- Chlorine - - . Chloride of Sodium - 24-578 23-687 0-8906 8-509 0-8(i2 1-420 23-87 22-858 1-012 2-663 0-708 0-829 0-840 2-88 3-50 24-109 23 69 2304 0-C48 0-671 1-105 0-888 0-047 ■ 0-2426 0-191 0-315 8-613 2-73 22-16 22-11 After 240 hours' actioD. After 376 h sure' action. Total residue Mineral salts Organic matter - Suspended matter Clilorine Chloride of Sodium - 24-578 23 -087 0-8906 8-509 0-862 1-420 22-5:34 21-517 0917 1-88 0-674 1 i;o 2-044 2170 1-629 0188 0310 8316 9161 46-423 21-8 21--'. 22-507 21 -698 0-809 1-584 2-071 1-989 1-925 8-426 8-397. 54-85 1 534 FLAT RODS. "Apart from its special interest, as compared with the following experiment, made simultaneously through charcoal, the following points are in themselves remarkable in the results obtained by this filtration through sand : "1st. That the filter continued increasing in efficacy even till the conclusion of the ex- periment, i. e., for 376 hours, not having lost any of its power when the experiment was terminated. " 2d. That no weighable quantity of dissolved organic matter was removed by the sand iu this experiment ; but it must be remembered that the quantity originally present was but small. " 3d. Its power of removing soluble salts was considerable ; as a maximum, 21 percent, of the common salt being separated." Results of Charcoal Filtration. Original Water used. After 12 hours' action. After 120 hours' action. CompariBon. Amount separated. Percentage ratio of Quantity separated. r, ! Amount Comparison. ^ , *^ separated. Percentage ratio of Quanlily separated. To al residue Mineral salts Orfranic matter - Suspended matter Chlorine Chloride of Sodium - 24-578 23-687 0-&9H6 8-509 0-SC2 1-420 22-13 21375 0-755 2-448 2-312 0-13D6 9-906 9-76 15-22 21-644 3-06 2-934 0-449 11-93 12-79 After 240 hours' action. After 316 hours' action. Total residue - Mineral salts Organic matter - Suspended matter Chlorine - . - Chloride of Sodium - 24-578 23-687 0-S906 3-509 0-SG2 1-420 20-821 2-79 3-757 0-719 15-28 20-43 21-374 20-604 0-770 3-204 3-033 0-1206 13-03 12-34 13-54 On comparing this experiment with the preceding, the following point comes out as showing the difference between the effects of sand and charcoal as filtering media. By the charcoal, speaking generally, a considerably larger quantity of the total residue contained in the water was removed than by the sand, their maximum results being respec- tively as follows : — Amount originally present. Amount separated in Grains in the Gallon. Amount separated in percentage of the Quantity present. By S.ind. By Charcoal. By Sand. By Charcoal. 24-578 grains in) the gallon j^ 2-074 3-757 8-426 j 15-28 Mr. Way has also shown that agricultural soil possesses the power of separating the soluble salts and organic matter from water in a remarkable manner. There are without doubt many natural phenomena which are immediately dependent upon this power, possessed by porous bodies of all kinds, in a greater or a less degree. FLAT RODS. In mining, a series of rods for communicating motion from the engine, horizontally, to the pumps or other machinery in a distant shaft. FLAX. After pulling, the treatment of flax varies in different <*ountries. In Russia, part of Belgium and Holland, and in France, the plant after being pulled is dried in the sun, being set up on the root end in two thin rows, the top interlacing in the form of the letter V inverted. The sun and air soon thoroughly dry the stems, and they are then made into sheaves, and the seed afterwards beaten oft'. The stems are steeped subsequently. Another mode, in general use in Ireland and in part of Flanders, is to steep the green stems immediately after they are pulled. In Flanders, the seed is invariably separated from the stems before the latter are inmiersed in water. In Ireland, although this is practised to some extent, yet the great bulk of the flax crop is put in the water at once, with the seed capsules attached, ami consequently there is a very considerable annual loss to the country by this waste of a most valuable product of the plant. In the Walloon country of Belgium, in its eastern provinces, and in the greater part of Germany, dew-rcttivg is practised. That is, in place of immersing the stems in water, they are spread thinly on short grass, and tlie action of the dews and rains ultimately effects what immersicn in a running stream or pool aceoniplishos in a nuich shorter time, namely, the decomposition of the gum which binds the fibrus to the stem and to each other. Fibre obtained by this method is, however, of very inferior quality and color. FLAX. 535 If the fibre of flax be separated from the stem without the decomposition of this matter, it is found to be loaded with impurities, which are got rid of afterwards in the wet-spinning, the boiling of the yarn, the subjection of the woven fabric to the action of an allialine lye, and the action of the atmosphere, — of rains and of alternate dippings in water, acidulated with sulphuric acid, and of a solution of chloride of lime, which are all required to perfect the bleaching. The great object, therefore, is to obtain the fibre as nearly free from all for- eign substances as possible, and, consequently, the mechanical separation of it from the woody pith of the stem is not to be recommended. At various periods attempts have been made to prepare flax fibre without steeping. Weak acids, solutions of caustic potash, and of soda, soap, lye, and lime, have all been tried, but have all been found objectionable. In 1815, Mr. Lee brought before " the trus- tees of the linen and hempen manufactures of Ireland " his system of separating the fibre without steeping. He alleged that a large yield was thus obtained, that the coloring mat- ter could afterwards be discharged by the most simple means, and that the fibre possessed greater strength. But it was found that the system was practically worthless. In 1816, Mr. Pollard, of Manchester, brought forward a plan of the same nature, and proposed to make an article from flax, which could be spun on cotton machinery. This also fell to the ground. In France and Belgium, at different periods, similar projects were found equally impracticable. In 1850, and again in 1857, Mr. Donlau revived the same, but the same fatal objections prevented the success of the system. The fibre was loaded with impurities, and the apparently larger yield over steeped fibre, consisted solely of these very impurities, which had to be got rid of in the after processes of manufacture. At the same time it must be recognized that the " dry separated " fibre can be rendered useful for one class of man- ufactures, viz., those where no bleaching is necessary, and its great strength is here an object. For ropes, rick-covers, tarpaulins, railway-wagon covers, &c., where pitch or tar are used, and prevent the decomposing action of moisture and of atmospheric changes, this mode of obtaining flax fibre is highly useful. The immersion of the flax stems in water, either as pulled full of sap, or after drying, appears, as yet, to be the best mode of effecting the decomposition of the gum, and obtain- ing the fibre pure or nearly so. The water most suitable for this purpose is that obtained from surface drainage, springs generally holding more or less of mineral matters in solution. Spring water from a calcareous soil is peculiarly unsuitable, the carbonate of lime which it contains being adverse to the putrefactive fermentation of the vegetable extractive. In Russia much of the flax grown is steeped in lakes. In Holland, it is always steeped in pools filled with the surface drainage. In France and Belgium, it is either steeped in pools or rivers. In England and Ireland generally in pools, though occasionally in rivers. The most celebrated steep-water in the world is the river Lys, which rises in the north of France, and flows through the west of Belgium, joining the Escant at Ghent. Although the water of this stream has been analyzed, chemists have not been able to discover why it should be so peculiarly favorable to the steeping of flax. All along its course flax is steeped. The trade is in the hands of factors, who purchase the dried stems from the growers, and undertake all the after processes, selling the fibre to merchants when it has been prepared for sale. The apparatus iu use consists of wooden crates, 12 feet long, 8 wide, and 3 deep. The sheaves of flax-straw are placed erect in the crates, and the root ends of one are tied to the top ends of another, to secure uniformity of packing. The crate, when filled, is carried into the river, and anchored there, the upper part being sunk, by the weight of stones, 6 inches underneath the surface. The period of steeping begins in May, and ends about September. The previous year's crop is thus steeped, having lain over in the state of dried straw during the winter. All the flax thus treated produces fibre of a yellowish white color, very soft and lustrous, with very finely divided filaments, and strong. From it almost exclusively is made cambric, the finest shirtings, and damask table- linen. It is a strange fact that flax straw is brought to the Lys, from a great distance, and even from Holland, as no other water has yet been found to give such good fibre. In 184Y, a new system of steeping was introduced in Ireland, l)y Mr. Schenck, of New York. It had been successfully tried in America on hemp, and the inventor crossed the Atlantic to try its efficacy on flax. His plan consisted in hastening the putrefactive fer- mentation of the vegetable extractive by artificially raising the temperature of the water to 90^ Fahrenheit. By this means, instead of an uncertain period of seven to twenty-one days being required for the steep, according to the state of the weather, and the tempera- ture of the atmosphere, the flax was retted uniformly in sixty hours. The flax straw, after the separation of the seed, is placed in wooden or brick vats, and the heat is communicated by forcing steam into a coil of iron or leaden pipes, placed under a false bottom perforated with holes. The annexed plan (///. 202) of a retting on Schenck's system, capable of consuming annually the produce of 4V)0 acres of flax, and employing, in all the operations of seeding, steeping, drying, and scutching, 30 men and 55 girls and boys, or an aggregate of 85 per- sons, win give an idea of the arrangements. The seeding-house requires to be of large size, 636 FLAX. as flax straw is a bulky article. It is on the ground floor, for the convenience of carting in the flax. The loft above it is used for cleaning and storing the seed. The vat and sprt-ad- ing-rooms are in a building of one story only, built with a vaulted roof resting on pillars. 292 « » ■§■» ■» _< iBsS • M e SPREAClNG KOJM 00-00 01 10 do 00 =CUTCfr-M'LL S^EDIHC HCUSS That part of the roof which is over the vats has lower windows to aid the escape of the vapors from the vats. The drying sheds at the top of the plan are on an open space, well exposed to the wind, and fifty or sixty feet apart. The hot-air rooms or desiccating house are fire-proof, each room capable of containing the flax turned out in one day's work. The .scutch mill, with engine and boiler-house, complete the plan. The advantages of this system were so manifest that it was speedily adopted in many parts of the United Kingdom and of the Continent. It was found, however, to have some defects. The small quantity of water soon became thoroughly saturated with tlie products of decomposition, and tlie fibre of the flax when dried, was, consequently, found loaded with a yellow powder, offensive to the smell, causing inconvenience in the preparing and spinning, and worse still, acting prejudicially on the quality of the fibre itself, rendering it harsh and dry. To obviate tliese defects, Mr. Powniall, of London, conceived the idea of pressing the flax straw, immediately when taken out of the steep, between a pair of smooth cast-iron cylinders, while, at the same time, a stream of water played upon the rollers. By these means the foul water of the vat is pressed out of the flax stems, which are flattened and bruised, thus tending to aid the separation of the bundles of fibres into minute filaments, while the stream of water effectually washed away all remaining impurities. It has recently been found that better fibre can be obtained by reducing the temper- ature and extending the time of steeping. The most perfect adaptation of Schenck's sys- tem is at the rettery of M. Auguste Scrive, near Lille, and ^7. 293 is a representation of it. Tanks of wood or stone are used, each to contain two and a half tons of flax straw. The straw is classified according to quality and length before being packed in the tank. It is put in erect, the root ends resting on the perforated false bottom, and slightly pres. 308 J stricks of fibrous material at or nearly at right angles to the fibres thereof, and to retain that position at the commencement of their downward motion ; whereby as the belts, sheets, or chains continue to descend, the hackles are drawn through the fibrous material for the purpose of removing the short fibres and extraneous matter. Another great advantage resulting from this improved mode of attaching the hackle bars b to the belts, sheets, or chains a, is, that the hackles can be made to enter the fibrous material at a point closer to the holder than in any of the sheet machines now in use. When the hackles are passing round the drums d d, they are cleansed by the revolving brushes jj, which deposit the ma- terial removed from the hackles on to the card drums k k. These drums are cleansed or doffed by the combs 1 1, or in any other convenient manner. This machine is also used to a very large extent, and well liked for dressing half line and full length flax. For this purpose the sheets require to be made six inches longer from centre to centre, and the head or trough to lift 3 inches higher, and the top rollers to ap- proach and recede from each other simultaneously with the rising and falling of the head. Combe, of Belfast, has recently produced another edition of Wordsworth's machine. Its novel feature consists in dispensing with bars altogether, in carrying the hackles and in fixing them directly on the leather sheets. By this means a very true action is obtained, and the working parts are so light, that the machine bears any speed with scarcely any wear and tear. In this invention there are also combined convenient modes of regulating the lift and severity of the cutters to suit different kinds of flax, and the holders are carried through the machine by a separate apparatus for that purpose, while they are at their high- est elevation, instead of during the whole process of lifting, as had always been the case in other machines. A machine has been lately invented, and brought out by Sir P. Fairbairn and Co., of Leeds, called Heilmann's tow-combing machine, {fir/. 309,) which, on trial, is much ap- proved of. The tow is first carded in the ordinary way, say on a breaker card, and then on a finisher card ; the latter delivers the tow in the shape of a sliver into cans, which are next placed at a, or back of the tow-combing machine. From the cans a the tow goes to the back conductor b, divided into as many compart- ments as there are slivers ; and from the conductor n, to the feeding-box c suspended on shaft D, without being keyed to it. The front lip e of the feeding-box is fluted and fitted with leather, and a corresponding nipper f hung from the same shaft d, and keyed upon it, completes the jaw which has to hold fast the tow, while the cylinder r. combs it. The feeding-box c derives its motion from the nipper f, which is moved by lever and eccentric as shown, and follows that iiip|>cr by its own weight, until stopped by india-rubber buffers ii ; when the nipper f in going further back leaves it, and the jaw e f opens for more tow to be fed, and the tow already combed to be drawn through the detaining comb i, as explained hereafter. The top K of feeding-box is movable up and down, by means of the connecting rod l, 550 FLAX. luing on a fixed centre M, so that the top part K opens or shuts as the body of the box goes backwards or forwards. The levers N N N are only used to keep the top and bottom of the box parallel to each other. 309 As shown in the drawing, the top of the feeding-box is fitted with hackles passing through two grates o and p, fast on bottom of feeding-box, and leaving between them a space through which the sliver has to pass. By the above arrangement, the hackles are caused to withdraw from the tow, while the whole box is drawn backwards on slides of table q, by the eccentric motion r r r. The last backward motion takes place while the jaw f is yet shut, and the top of the box up ; but when the latter has got closed again, then the whole box slides down on the table Q to its former position, bringing with it the sliver of a quantity equal to that move : this com- pletes the feeding motion. Now as the feeding-box recedes, the lip e comes nearer to the combing cylinder G, the hackles s s cleaning tlie tow projecting outside the nipper f. As soon as they are passed through, the feeding-box comes back to the most forward position, when the nipper f leaves it, and the jaw e f opens : at the same time the two rollers t u have reached their top posi- tion. The top one t is then thrown forwards (by the lever arrangement shown in v v v) upon the leather w, stretched on parts of surface of cylinder g ; this roller t is thus driven, and takes hold of the points of the tow presented to it by lips or bottom jaw e ; a fine de- taining comb I being just before interposed between them to keep back the noils that have not been carried off by the combing cylinder. In that way the points of the tow are driven upon the sheet x, until the roller t, by being thrown back again off the leather w, their motion is stopped at the same moment, the two rollers u and t are allowed to drop .down by eccentric v, drawing with them (through the detaining comb i, and quite out of the rest of the sliver) the other ends of the fibres of which they have got hold. While this has been going on, the feeding-box has advanced the sliver a step, the nip- per closed, and forced the said feeding-box forwards so as to bring the lip e within the reach of hackles s on cylinder g, which then met it, cleansed the tow, and so on as before. At that time the rollers t and u come up again, and during that upward motion the lat- ter ends of the fibres partly combed and overturned by the cylinder hackles, as shown in drawing, are combed by them in their turn. Then the roller t is once more driven round by the leather w stretched on cylinder, the new points place themselves above tlie back ends FLY POWDER. 551 of the fibres combed before, and are carried forwards into a continuous sliver on the leather sheet X, from the leather sheet to the rollers z z, then to the trumpet conductor a, the front delivery roller c, and (when more than one head to the machine) from c to the end delivery c, over the conducting plate d. In e, /, g, and A, arc the usual brusli, doffer, comb, and tow box for the noils. These combing machines are made of different sizes to suit all sorts and lengths of tow ; the yarn produced from them is nmcli finer than that produced by the ordinary carding sys- tem alone. The combed tow can generally be spun to as high numbers as the line from which it has been combed, and in some instances has produced good yarn, even to higher numbers. The combed tow, after the combing machine, is passed through a system of drawing, roving, and spinning, similar to that used for cut line. 310 U=o Combe, of Belfast, has lately introduced an improvement in the roving frame. It con- sists in the application of a peculiar expanding pulley, instead of the cones or discs and runners which have hitherto been alwa3's used for the purpose of regulating the " take-up " of the bobbins. It is evident that a strop of 2 or 3 in. broad, working over the cones, placed with the small end of one opposite the large end of the other, is an imperfect and rude mechanical contrivance, and that there must be a constant straining and stretching of the belts. There is the same imperfection attending the disc and runners. The expanding pulley is free from these objections, as its acting surface is a line, and therefore it works with the greatest accuracy, while it is also a great simplification of the machine generally. In rovings for flax and tow it is generally driven directly from the front roller, by which means a large number of wheels and shafts are avoided. FLUVIATILE, (Jluvius, a river,) belonging to a river. FLY POWDER. Under this name they sell on the continent the black -colored powder obtained by the spontaneous oxidizement of metallic arsenic in the air. Various prepara- tions of white arsenic are used for the same purpose in this country. King's yellow is much used ; it should be made by boiling together sulphur, lime, and white arsenic, but much that is sold is merely arsenic and sulphur mixed. Objecting on principle to the familiar use of arsenic and dangerous substances, a prefer- ence may be given to a substitute for the above, made by boiling quassia chips into a strong decoction and sweetening with loaf sugar. This seems to have deadly power over the flies. 552 FOUNDING. who can scarcely quit the liquid without imbibing a deadly potion, and they are seen to fall from the ceilings and walls of the rooms soon afterwards. Many of these compounds for killing flies are supposed by their odor to attract flies into the rooms. The inconvenience to manufacturers and others from flies, may be obviated in many cases where apartments are required to be kept as free as possible from them, by reference to facts recorded by Herodotus, of fishermen surrounding themselves with their nets to keep off the gnats. We are indebted to William Spence, Esq., F.R.S., for some very curi- ous particulars respecting the common house fly communicated in a paper to the Entomo- logical Society. The common house fly will not in general pass through the meshes of a net. The inhabitants of Florence and other parts of Italy are aware of this fact, and pro- tect their apartments by hanging network up at the windows, thus at all times the doors and windows may be kept wide open by hanging a light network over the aperture ; the meshes may be of considerable width, say enough for several flies on the wing to pass through, and no fly will attempt to pass, unless there be a strong light, (another window opposite, or re- flection from a looking-glass.) A knowledge of this simple means of protection from flies on the wing may prevent inconvenience from these intruders, and obviate the necessity for poisons to destroy them. — T. J. P. FOUNDING. In foundries attached to blast-furnaces, where from 20 to 30 tons of iron are made pfr diem, the moulds are generally mere troughs cut in the sand in which the melted metal flows and cools in contact with the air. The surfaces of the castings made in this manner present appearances which vary according to the quality of the iron. The kinds of iron adapted for founding purposes are those which are most fluid when melted, and which contain most carbon, and are called Nos. 1 and 2. They are distin- guished by the surface of the pig of iron, which was exposed to the air during cooling, being smooth, and presenting a slightly convex figure. The surfaces of Nos. 3 and 4 pig iron, and of the white crystalline pig iron (most suitable for making into wrought iron) present a concave figure, and the surfaces are very irregular and pitted with holes. The color of the fracture, and the closeness of the grain, also indicate the proportion of carbon in pig iron. The mixtures of metal, melting temperatures of metal, &c., require the closest observa- tion on the part of the workmen and ' foremen who practise iron founding, and these me- chanics are in the practice of observing diflerences so minute that they cannot be appre- ciated by the chemist, or expressed in words. Machinery has enabled the modern founder, by means of railways, turn-tables, travelling cranes, and steam-power, to move at will the heaviest masses without confusion and with great expedition ; but nothing but the traditions of the factory, and the constant habit of observation will enable him to conduct properly the melting and casting of metal so as to an-ive at certain results. This is proved by the constant failures of those who undertake to make descriptions of castings, of which they have had no previous knowledge. Each branch of foundry work must be studied in detail, and we can only pretend to indi- cate those directions in which progress has been and is being made. Foundry. — The process of iron smelting and the construction of furnaces having been described under other heads, the remaining part of the business of a foundry, viz., that which relates to the preparation of the moulds and moulding, will now be described. ifouldinf). — The art of moulding is one of the most important processes carried on in a foundry, and the success of the founder is directly proportioned to the skill and ingenuity brought to bear upon the production of the patterns and the system of moulding. Before metals can be cast into the variety of shapes in which they are wanted, patterns must be prepared of wood or metal, and then moulds constructed of some sufficiently infu- sible material capable of receiving the fluid metal, and retaining it without uniting with it until it has solidified. A mixture of sand and loam (packed tightly into metal boxes, called flasks) is genially chosen as the material for making moulds, and is employed advantageously for seveial im- portant reasons. Flasks. — In modern foundries a system has been invented, by which flasksof any dimen- sions may be constructed by means of bolting together a number of rectangular frames of cast-iron, so arranged as to admit of being easily connected together. When the particular castings for which the flask has been constructed, or rather com- pounded, are completed, the separate pieces are unbolted, and are ready to be combined in some new form appropriate to the dimensions of the pattern next to be moulded in them. The loss of capital, &c., invested in flasks, only occasionally used, is thus saved, as well as loss of time in .searching for the size req\iired. The space devoted, on the old system, to the reception of flasks belonging to a foundry was very large, and this may now be appro- priated to other purposes. Sand and loam. — Founders formerly used, on account of price, the description of sand most accessible to them, but at the present time the convenience and cheapness of railway carriage have enabled special qualities of sand to be delivered to all parts of England. FOUNDING. 553 For founding purposes sand is much improved by the admixture of coke, crushed and reduced to a fine powder, and a mill for this purpose is as necessary in every large foundry as those for grinding and mixing loam. Moulding sand must be a mixture of a large quantity of silex and a small quantity of alumina — the property of the latter material being to cement the grains of silex together. Loam consists of the same materials mingled in opposite proportions. The preparation of loam for those purposes for which sand is not adapted, is an impor- tant duty in a foundry, for a great quantity of loam cores have to be made and dried in proper ovens, which is a tedious operation. Many castings, such as the screws for steamers, are more conveniently cast in moulds constructed of wet loam. These are shaped to the required form when the clay is moist, and then carefully dried afterwards. Other castings are of such peculiar shapes that they can only be produced in moulds that take in a vast number of pieces. These moulds are then formed of a number of pieces of hardened sand, held together by strips of iron or of plaster, if the sand used is not coherent enough of itself. Compounds of silex and alumina arc very infusible, and when moistened with water and faced with carbonaceous matter, they arc capable of receiving the most delicate impressions from the patterns which the founder employs. Grains of sand are so iflln^gular in shape themselves that they leave innumerable irreg- ular spaces between them, and these intervals form a network of channels which permit the rapid escape of the gases, which are so violently generated by the contact of hot metal falling upon wet sand. Machine Castings. — Every year, engineers order castings to be prepared of more diffi- cult and complicated forms, and with greater perfection of surface than they have required before. The reason of this is, that with the progress of the mechanical arts, larger and stronger machines are continually being introduced. In these machines greater steadiness of cast- iron framework is necessary, than can conveniently be obtained when the frame is made out of a number of pieces of iron cast separately and then bolted together. It would bo impossible to mould large frames with pieces projecting on all sides, (prepared to receive the moving parts of the machines,) and jutting out in contiary directions, in any flasks filled with wet sand, for the pattern never could be removed without destroying the impression. To meet these difficulties the modern iron founder has had to follow those plans which were first proved practicable by those who have devoted themselves to casting bronze statues. In founding, as in so many other branches of manufacture, the discoveries made in prose- cuting the fine arts have been advantageously adopted by those engaged in works of utility. False Cores. — The introduction of the drawbacks, or false cores, made of sand pressed hard, (and admitting of taking to pieces by joints, at each of which a layer of parting sand is prepared,) used for figure casting, enables the moulder to work at his leisure, without fearing that his mould may tumble to pieces, and also enables him to fashion these draw- backs or cores into the most complicated forms, with the power to remove them while the pattern is removed, and build them up again round the empty space (formerly occupied by the pattern) with the greatest facility and accuracy. The woi-kmen whose occupation is to knead the sand into the forms required by the founder, are termed moulders, and they form a very numerous body of mechanics, de- manding and receiving high wages. The moulder has often only his sand, his flasks, cranes, and a few simple tools, (for smoothing rough places, and for repairing the places in the sand, where the mould has broken away during the lifting of the pattern;) he has to make proper arrangements for the exit of the atmospheric air which leaves the mould as the fluid metal takes its place ; and he is expected to produce an exact copy in metal from any pattern, simple or conii)li- cated, which may be brought before liim. It will be evident that to produce a good result with such imperfect appliances as the ordinary moulder uses, a skilful workman must be employed, and time expended in pro- portion to the difficulty of the operations to be performed. Where only a few impressions from a model are required, it is not worth while to spend money in making expensive patterns, or providing those'appliances which may enable pat- terns to be moulded with facility and little skill; but where thousands of castings are wanted of one shape, it is expedient to spend money and skill on patterns and tools, and reduce the work of the moulder to its minimum. Management. — The best managed foundry is not that in which good eastings are obtained by the employment of skilled workmen at a great expense, and without trouble or thouglit on the part of tlie principal, ))ut rather that in which the patterns have been con- structed with a special reference to their licing cast with the minimum of skill and (he maximum of accuracy. It is only by the forethought and calculation of the manager that subsequent operations can be reduced to their smallest cost ; and in the foundry, as in all 554 FOUNDING. other manufactorieg, the true principles of economy are only practised where the head work of one person saves the manual labor of a large number. Improvements. — The attention of founders has been turned — 1st, to the methods by which the labor of making moulds in sand might be reduced ; 2d, to the introduction of improvements in the mode of constructing patterns and moulds ; and Sd, to the manufacture of metallic moulds for those purposes for which they could be applied. A great progress has been made during the last twenty years in these dilfercnt directions. Machine Moulding. — In the large industry carried on for the production of cast-iron pipes for the conveyance of water and gas, machinery has been applied so that the operation of pipe-moulding is performed almost without manual labor, with great rapidity and precision. The co.-e is often sufficient to cause a terrible detonation. A spatula of pa.steboard or very thin wood should be employed to transfer it into its receptacle. Fulminating silver should not be kept in 558 FUR. glass vessels, for fear of the salt finding its way between the cork or stopper, the slightest movement with a view of opening the vessel, being then sufficient to cause an accident. Small paper boxes are the safest to keep it in. Fulminating silver gives a more violent detonation than the corresponding mercurial compound. The presence of roughness or granular particles on the substances with which it may be in contact, assists greatly in causing it to explode. Although giving so violent an explosion when alone, it may be burnt without danger when mixed with a large excess of oxide of copper, as in the ordinary process of organic analysis. It then gives off a mixture of two volumes of carbonic acid, and one volume of nitrogen. Gay-Lussac and Liebig made an analysis of the salt in this manner, with the annexed results : E.xperimont. Calculation. Carbon . - 1-9 C* - 24 - 8-0 Nitrogen . - 9-2 N^ - 28 - 9-3 Silver - - V2-2 Ag» - 216 - - 72-0 Oxj-gen - - 10-7 0* - 32 - 10-7 100-0 300 100-0 For further remarks on the fulminates, see Fulmixatixg Mercury. — C. G. W. FUR. Furs arc subject to injury by several species of moths, whose instinct leads them to deposit their eggs at the roots of the fine hair of animals. Linna?us mentions five species that prey upon cloth and furs, of which Tinea pellionclla, T. I'Cfitionella and T. tapclzella are the most destructive. No sooner is the worm hatched than it cats its path through the fur, and continues increasingly destructive until it arrives at its full growth, and forms itself a silken covering, fiom which, in a .short time, it again emerges a perfect moth. Another cause of the decay of fur is the moisture to which thfey are frequently exposed ; the delicate structure of the fine under fur cannot be preserved when any dampness is al- lowed to remain in the skin. This fact is well known to the leather manufacturer, who, having wetted his skins, allows them to remain in a damp cellar for a few days, for the pur- pose of removing the hair, which is pulled out with the greatest facility, after remaining only one week in a moist condition. It follows from these observations, that to preserve the fur it is necessary to keep them dry, and to protect them from moths; if exposed to rain or, damp, they must be dried at a moderate distance from the fire ; and when put by for the summer should be combed and beaten with a small cane, and very carefully secured in a dry brown paper or box, into which moths cannot enter. During the summer they should be examined once a month to be again beaten and aired, if the situation in which they have been placed be at all damp. With these precautions, the most valuable furs may be pre- served uninjured for many years. FUSEL OIL. During the rectification of corn or grape spirits there is always separated a fiery fo-tid oil of nauseous odor and taste. It is this substance which is the cause of the unpleasant effects which are produced upon most persons by even a small quantity of in- sufficiently rectified whiskey or brandy. Any spirit which produces milkincss on the addi- tion of four or five times its volume of water, may be suspected to contain it. By repeated rectification every trace may be removed. Fusel oil invariably consists of one or more homologues of the vinic alcohol, (CH^O",) mixed with variable quantities of the latter substance and water. The nature of fusel oil varies much with the source from whence it is obtained. That which is ordinarily sold in this country for the purpose of yielding pear essence consists mainly of the amylic alcohol, (C^"II"0'^,) mixed with from one-fourth to one-fifth of spirit of wine. Tlie progress of organic chemistry has been greatly assisted by the researches which have been made upon fusel oil, almost all the amylic compounds hitherto obtained having been directly or indirectly obtained from it. To obtain fusel oil in a state of purity it is necessary, in the first place, to rectify it frac- tionally. By this means it will be found that much alcohol can be removed at once. If a great quantity of water and very little vinic alcohol be present, the simplest mode of puri- fication is to shake it with water, by which means common alcohol is removed in solution, while the amylic alcohol, owing to its comparative insolubility, may be easily separated by the tap-funnel. After drying over chloride of calcium, it is to be again rectified once or twice, only that portion distilling at about 269'6° Fahr. (132° Cent.) being received. The product of this operation is pure amylic alcohol, from which an immense number of deri- vations of the amylic series can be obtained. By treatment with sulphuric acid and bi- chromate of potash it is converted into valerianic acid. In this manner all the valerianic acid now so nnich emploj-ed in medicine is prepared. By distilling amylic alcohol with sul- phuric acid and acetate of potash, we obtain the acetate of amyle, commercially known as jargonelle pear essence. The foreign fusel oils obtained from the grape marc contain several homologues higher GALVANIZED IRON". 559 and lower ia the series than the amylic alcohol. In fact, it would appear that during the fermentation of grapes there are formed, not only alcohols, but ethers and acids. M. Chancel, by repeatedly rectifying the dehydrated and more volatile portions of the residues of the distillation of grape marc alcohol, succeeded in isolating a fluid boiling at 205" Fahr. This proved to be pure propionic alcohol. M. Wurtz has also been able to obtain the butylic alcohol by rectifying certain specimens of potato oil. All fusel oils are not so complex. The author of this article has repeatedly examined specimens of English and Scotch fusel oil, which did not contain any thing save the ethylic and amylic alcohols, accompanied by small portions of the acids, which are procured by their oxidation. M. Chancel has given the following equations, which explain the manner in which saccharine matters break up into homologous alcohols under the influence of fer- ments. I have reduced the unitary notation employed by him into the ordinary formulae used iu this country, in order to render the relations as clear as possible to the reader. 2C'-H'^0" = 8C0= + 4C^II°0^ Glucose Alcohol. . 2C''H''0'' _ SCO- + C^IFO- + 2C''irO' + 2no. Propionic alcohol. 2C"H'=0'^ _ gQQ". ^ 2C^IP°0^ + 4nO. 2Ql".^l".Qli Butylic alcohol. 8C0^ + C^H'-O^ + C'H'W + 4H0. Amylic alcohol. M. Chancel appears to consider the last equation as indicating the necessity of propionic alcohol being always formed wherever amylic alcohol is generated ; but this is not in ac- cordance with the results of those chemists who have examined crude amylic alcohol re- peatedly for propionic alcohol, but without finding any. The formation of these ijitcrest- ing homologues appears therefore to depend upon special circumstances connected with the fermentation. The caproic alcohol is also contained in certain varieties of fusel oil. Fusel oil has been patented as a solvent for quinine, but its odor, and more especially that produced by its oxidation, so persistently adheres to any thing with which it has been in contact, that great care is requisite in the purification. It is remarkable that at the first instant of smelling most specimens of fusel oil, the odor is not unpleasant, but in a very few seconds it becomes exceedingly repulsive, and provokes coughing. — C. G. W. G GALVANIZED IROX. This is the name, improperly given, first in France, and sub- sequently adopted in this country, to iron coated with zinc by a peculiar patent process. In 1837, Mr. II. W. Crawfurd patented a process for zincing iron. In the '■'■ Repcrtorn of Patent Inventions'''' his process is thus described: Sheet iron, iron castings, and various other objects in iron, are cleaned and scoured by immersion in a bath of water, acidulated with sulphuric acid, heated in a leaden vessel, or used cold in one of wood, just to remove the oxide. They are then thrown into cold water, and taken out one at a time to be scoured with sand and water with a piece of cork, or more usually with a piece of the husk of the cocoa nut, the ends of the fibres of which serve as a brush, and the plates are after- wards thrown into cold water. Pure zinc covered with a thick layer of sal ammoniac is then melted in a hath, and the iron, if in sheets, is dipped several sheets at a time in a cradle or grating. The sheets are slowly raised to allow the superfluous zinc to drain off, and are thrown whilst hot into cold water, on removal from which they only require to be wiped dry. Thick pieces are heated, before immersion, in a reverbeiatory furnace, to avoid cooling the zinc. Chains are similarly treated, and on removal from the zinc recjuire to l)e shaken until cold, to avoid the links lieing soldered together. Nails and small articles are dipped in muriatic acid, and dried in a reverberatory furnace, and then thrown all together in the zinc, covered with the sal ammoniac, left for one minute, and taken out slowly with an iron .skimmer. They come out in a mass, .soldered together, and for their separation arc after- wards placed in a crucible and surrounded with charcoal powder, then heated to redness and shaken about until cold, for their separation. Wire is reeled through the zinc, into which it is compelled to dip l)y a fork or other contrivance. It will be understood that the zinc is melted with a thick coat of sal ammoniac to prevent the loss of zinc by oxidation. 560 GAKNET. Mr. Mallett coated iron with zinc by the following process : The plates are immersed in a cleansing bath of equal parts of sulphuric or muriatic acid and water, used warm ; the works are then hammered and scrubbed with emery and sand to detach the scales, and to thoroughly clean them ; they are then immersed in a " preparing bath " of equal parts of saturated solutions of muriate of zinc and sal ammoniac, from which the works are transferred to a fluid metallic bath, consisting of 202 parts of mercury and 1,292 parts of zinc, both by weight, to every ton weight of which alloy is added above one pound of either potassium or sodium, the latter being preferred. As soon as the cleaned iron works have attained the melting heat of the triple alloy, they are removed, having become thoroughly coated with zinc. At the proper fusing temperature of this alloy, which is about 680^ Fahr., it will dissolve a plate of wrought iron of an eighth of an inch thick in a few seconds. Morewood and Rogers' galvanized tinned iron is prepared under several patents. Their process is as follows : The sheets are pickled, scoured, and cleaned, just the same as for ordinary tinning. A large wooden l)ath is then half filled with a dilute solution of muriate of tin, prepared by dissolving metallic tin in concentrated muriatic acid, which requires a period of two or three days. Two quarts of the saturated solution are added to 300 or 400 gallons of the water contained in the bath. Over the bottom of the bath is first spread a thin layer of finely-granulated zinc, then a cleaned iron plate, and so on, a layer of granulated zinc and a cleaned iron plate alternately, until the bath is full. The zinc and iron, together with the fluid, constitute a weak galvanic battery, and the tin is deposited from the solution so as to coat the iron with a dull uniform layer of metallic tin in about two hours. The tinned iron is then passed through a bath containing fluid zinc, covered with sal ammoniac mixed with earthy matter, to lessen the volatilization of the sal ammoniac, which becomes as fluid as treacle. Two iron rollers immersed below the surface of the zinc, are fixed to the bath and are driven by machinery to carry the plates through the fluid metal at any velocity previously determined. The plates are received one by one from the tin- ning bath, drained for a short time, and passed at once, whilst still wet, by means of the rollers, through the bath as described. The plates take up a very regular and smooth layer of zinc, which, owing to the presence of the tin beneath, assumes its natural crystalline character, giving the plates an appearance resembling that known as the nioiree metallique. — See HunVs Handbook to the Great Exhihiiion. It is stated that galvanized iron plates, cut with shears so as to expose the central iron, become zinced round the edges, and at the holes where the nails were driven. We are also informed that nngalvanizcd iron will, if moist when near galvanized plate, become zinced, and that telegraph wires, where cut through, become coated by the action of the rain water on the galvanized portion of the surfaces. It has been stated that the galvanized iron is not more durable than unprotected iron ; that, indeed, where the zinc is by any accident removed, the destruction is more rapid than ordinary. We have made especial inquiries, and find that in forges where there is any escape of sulphur vapor the galvanized iron does not stand well, but that under all ordi- nary circumstances it has the merit of great durability in addition to its other good qualities. GARXET. (Grcnat, Fr.) Garnet is a silicate of some base, which may be lime, mag- nesia, oxide of iron, &c. There are six sub-species of garnet, viz. : I. Alumina-lime garnet, consisting of the silicates of alumina and lime. II. Ahniiina-magnesia garnet, consisting of the silicates of alumina and magnesia. III. Alumina-iron garnet, consisting of the silicates of alumina and iron. IV. Alnmina-manganesc garnet, consisting of the silicates of alumina and manganese. V. Iron-lime garnet, consisting of the silicates of iron and lime. ' YI. Lime-ehrome garnet, consisting of the silicates of lime and oxide of chromium. I. Lime-garnet, or grossular, is composed of silica, 40-1 ; alumina, 22'7 ; lime, 37"2 =r 100-0. Color, pale greenish, clear red, and reddish orange, cinnamon color. Before the blowpipe, fuses to a slightly greenish glass or enamel ; soluble, when powdered, in concen- trated muriatic acid. This section comprises cinnamon-stone or Essonite, grossular or Wiluite, Romanzovite, topazoUte, and succinite. II. Magnesia-garnet is of a deep coal-black color, with a resinous lustre. The variety from Arendal is composed of silica, 42-45 ; alumina, 22-47 ; protoxide of iron, 9-29 ; pro- toxide of manganese, 6-27; magnesia, 13-43; lime, 6-53 = 10044. — (Wdchfmeister.) Be- fore the blowpipe, easily fusible, formmg with intumescence a dark grayi.sh-green globule, which is non-magnetic. III. Iron-garnet comprises the almandine or precious garnet, allochroite, and common garnet. It is composed of silica, 36-3; alumina, 20-5; protoxide of iron, 43"2 = 100-0. Before the blowpipe, fuses rather easily, with an iron reaction. IV. Manganese-garnet, or spessartine, is of a brownish-red color, and is composed of GEMS, ARTIFICIAL. 561 silica, 35'83 ; alumina, 18 '06 ; protoxide of iron, 14-93; protoxide of manganese, 30'96 = 99 '78. (Analysis of M. garnet from Haddam, U. S., by Seyhert.) Before the blowpipe, gives a manganese reaction. V. Iron-lime garnet includes aplome, colophonite, melauite, and pyreneite. These vary in color from dark red, brownish black, to black, and possess a shining lustre, which is sometimes resinous, as in colophonite. Analysis of the aplome of Alteuau: — Silica, 35-64; lime, 29-22; protoxide of iron, 30-e set on fire in an atmosphere of pure oxj-gen, but in lioth cases is covered with a film of oxide, which seems to protect it from further action. It is not acted cm by sulphur, but readily combines with chlorine and iodine by the aid of heat. Silicium unites readily with it, forming a hard, brittle substance, capable of taking a high polish. This substance is always formed when glucinum is prepared in porcelain ves- sels, the silica being reduced by this metal. After several fusions in such vessels, glucinum may contain as much as 20 per cent, of silicium. Glucinum does not decompose water at the temperature of ebullition, nor even at a white heat. Sulphuric and hydrochloric acids dissolve it easily, either concentrated or diluted, with the evolution of hydrogen. Nitric acid, even when concentrated, has, at ordinary temperatures, no action upon it, and dissolves it but slowly when boiling. Glucinum, though not acted on by ammonia, dissolves readily in caustic potash. The metal which Wohler obtained, by igniting chloride of glucinum with potassium in a platinum crucible, diflers considerably from that just described, the metal thus obtained being a gray powder, very refractory in the furnace, but combines with oxygen, chlorine, and sulphur much more energetically than the metal described by Debray. The difierences arise probably partly from the difTerent state of aggregation, and partly from the contami- nation of Wohler's metal with platinum and potassium. Berzelius effected the solution of the beryl by fusing the finely-powdered beryl with three times its weight of carbonate of potash in a platinum crucible, and then treating the fused mass with hydrochloric acid ; but the swelling up of the mixture of carbonate of pot- ash and beryl at the moment of fusion, prevents large quantities being made at a time. To obviate this, Debray uses lime. The following is the process given by him : The pulverized emerald is mixed with half its weight of quicklime in powder ; the mix- ture is then fused in an earthen crucible placed in a wind-furnace ; the temperature at which the fusion takes place is much lower than that required for the assay of iron. The glass thus obtained is powdered and moistened with water acidulated with nitric acid, so as to obtain a thick paste, to which is added concentrated nitric acid, taking care to stir the mass, which is converted, in the cold, but better by heat, into a homogeneous jelly ; this is evaporated to drive off" the excess of acid, then heated so as to decompose the nitrates of alumina, glueina, and iron. It is advisable to raise the temperature at the end of the oper- ation so as to decompose a small portion of the nitrate of lime. The result of this calci- nation is composed of insoluble silica, alumina, glueina, and sesquioxide of iron, insoluble in water, finally, nitrate of lime, and a little free lime. It is boiled with water containing Eome chloride of ammonium. The nitrate of lime is rapidly removed by the water, and the lime decomposing the chloride of ammonium is also at length dissolved, with liberation of ammonia. This disen- gagement of ammonia ceases as soon as all the lime is dissolved, and as it is the surest guarantee of the non-solution of the alumina and glueina, the calcination of the nitrates should be repeated, unless ammonia is liberated under the circumstances just mentioned. The residue of silica, alumina, glueina, and iron is well washed until all the lime is re- moved, which is known by oxalate of ammonia causing no cloudiness in the washings. The separation of the silica and the earths is easily effected, mere boiling with nitric acid dissolving the alumina, glueina, and iron, and leaving the silica undissolved. The solution of the nitrates of alumina, glueina, and iron is then poured into a solution of carbonate of ammonia, to which a little ammonia has been added. The precipitation of the earths takes place witiiout liberation of carbonic acid, and the glueina at length redissolves in the car- bonate of ammonia. The solution of the glueina may be considered complete after seven or eight days' digestion. As the carbonate of ammonia may dissolve a little iron, it is better to add to the solution a few drops of sulphide of ammonium, which precipitates it com- pletely. The solution is then filtered and boiled to drive off the carbonate of ammonia, when the glueina is precipitated in the state of carbonate. The carl)onate of glueina is a dense white powder, easily washed ; it is collected on a filter and dried. From the carbonate any of the other compounds of glueina may be easily prepared ; simple calcination converts it into glueina. A process for the separation of alumina and glueina has been proposed by M. Berthier; it consists in suspending the well-washed earths in water, and passing a current of sulphurous acid through them. Their solution is com- plete. The liquid is then boiled to expel the excess of sulphurous acid, when a dcns'^ ?ub- GLUCINUM. 569 sulphite of alumina is precipitated, leaving the glucina in solution. Debray found that sometimes in this process the glucina wa,s entirely precipitated with the alumina. Glucina thus obtained possesses the following properties: It is a light white powder, without smell or taste — infusible, but volatilizes just as zinc and magnesia. Heat does not harden glucina as it does alumina, but renders it nevertheless insoluble in acids. Boiling concentrated sulphuric acid dissolves it easily, but the action of nitric acid is very feeble when the glucina has been .strongly heated. Caustic potash dis- solves it readily ; and glucina is even capable of expelling the carbonic acid from carbonate of potash ; it is again precipitated from its solution in potash by boiling when diluted to a certain extent. Ebelmen has obtained it in hexagonal prisms by submitting a solution of glucina, in fused boracic acid, to a powerful and long-continued heat. It may likewise be obtained in microscopic crystals by a more easy process, which consists in decomposing the sulphate of glucina at a high temperature, in the presence of sulphate of potash ; also by calcining the double carbonate of glucina and ammonia. The crystals are separated from the sulphate of potash by washing. The hydrate of glucina is obtained by precipitating a salt of that base by ammonia. The presence of ammoniacal salts does not hinder the precipitation. When recently pre- pared it greatly resembles the hydrate of alumina, only it absorbs, by drying in the air, a notable fiuantity of carbonic acid. The hydrate of glucina easily loses its water by heat, and becomes then insoluble in car- bonate of ammonia, the hydrate when pure being very soluble in it ; but its solution is hin- dered by the presence of alumina, in which case it is only complete after several hours' digestion. It is also soluble in sulphurous acid and bisulphite of ammonia. Glucina precipitated from some of its solutions by ammoniii„ is rcdissolved by prolonged ebullition, but this is observed more especially when precipitated from the oxalate or ace- tate of glucina. Chloride', of glucinum is prepared by the same process as the chloride of aluminium, merely substituting glucina for alumina, and at first sight very much resembles it ; it is, however, much less volatile than chloride of aluminium, being about as volatile as chloride of zinc. It differs also from chloride of aluminium inasmuch as it is not capable of forming definite compounds with some protochlorides ; chloride of aluminium uniting with certain protochlorides forming a series of compounds, fusible at a low temperature, volatile at a red heat without decomposition ; and the composition of which is represented by the for- mula APCl'-f MCI. The crystals of chloride of aluminium may be called chlorinated spi- nelles, and are easily obtained, it being only necessary, in order to form the sodium com- pound of the group, to mix the chloride of aluminium with half its weight of common salt, and distil, one distillation producing it pure, the formula of it being APCP-f-XaCl. Chlo- ride of glucinum is very soluble in water ; it may, however, be obtained in crystals, by allowing its solution to evaporate over sulphuric acid under a bell jar. The presence of a little free hydrochloric acid favors the crystallization. Thus obtained, this salt is a hydrate, and according to Awdejew its formula is GlCl-i-4110. The hydrated chloride of glucinum is decomposed by heat into hydrochloric acid and glucina. Iodide of glucinum. — This compound presents all the characters of the chloride, only being a little less volatile. The affinity of iodine for glucinum is not very strong, oxygen decomposing the iodide at the heat of a spirit lamp, liberating iodine and forming glucina. Glucinum is also capable of combining with fluorine, the double fluoride of glucinum and potassium being formed by pouring a solution of fluoride of potassium into a salt of glucina. It is but little soluble in the cold, and is deposited in the form of brilliant scales. Sulphate of glucina. — This salt is white, has an acid and slightly sweet taste. It is un- alterable in the air at ordinary temperatures, but effloresces in dry and warm air. By heat it first fuses, in its water of crystallization, then at a red heat is decomposed into sulphurous acid, oxygen, and glucina. Water at 57*2''' F. (14" C.) dissolves about its own weight of this salt; its solubility is increased by heat, and boiling water dissolves an indefinite quantity. The presence of free sulphuric acid or alcohol lessens its solubihty. . It loses a portion of its acid in many cases with facility ; for instance we obtain an un- crystallizable tribasic sulphate of glucina, by dissolving carbonate of glucina in a concen- trated solution of the sulphate ; carbonate of glucina is added until carbonic acid ceases to be liberated at each addition ; the liquid, filtered and evaporated, gives a gummy residue. The very dilute solution of this salt lets fall some glucina, and is changed into a bibasic sul- phate, also uncrystallizable. Sulphate of glucina dissolves zinc with disengagement of hydrogen, forming a bibasic sulphate of glucina and sulphate of zinc. Sulphate of alumina, under the same circum- stances, dissolves zinc with liberation of hydrogen, and forms a sulphate of zinc and an insoluble subsulphate of alumina. Taking advantage of this difference, Debray proposed a method {Ann. Chijm. et Phys. xliv. 20) for the separation of alumina and glucina, but 570 GLYCERINE. which does not answer for analytical purposes, as chemically pure zinc is only acted on with great difficulty by these sulphates. Sulphate of glucina is formed by dissolving the carbon- ate in dilute sulphuric acid, the evaporated liquid depositing it on cooling. It is essential to keep the liquid distinctly acid ; it assists the crystallization, and besides, if we were to dissolve the carbonate m it until the liberation of carbonic acid ceased, we should obtain a basic uncrystallizable salt. According to Awdcjew the formula of this salt is G10,S0= + 4H0. Double snlphate of glucina and potash. — This salt was discovered by Awdejew ; he ob- tained it while endeavoring to produce the double sulphate of glucina and potash corre- sponding to common alum, (which, had he succeeded, would have been one of the best proofs of the analogy existing between alumina and glucina.) It is obtained in crystalline crusts, by evaporating a solution containing 15 parts of sulphate of glucina to 14 parts of sulphate of potash. The concentration is stopped as soon as the liquid becomes turbid ; at the end of a few hours this salt is deposited, which is purified by recrystallization. It is precipitated as a crystalline powder by the addition of sulphuric acid to the concentrated solution. It is but little soluble in the cold, much more so, though slowly, in hot water. By the action of heat it finst fuses in its water of crystal- lization, then is decomposed entirely into glucina and sulphate of potash, if the heat is strong and long enough applied. Its composition is represented by the formula G10,S0'-fK0,S0V2H0. Carbonate of glucina. — Glucina is soluble in carbonate of ammonia. When the solution is boiled, carbonate of ammonia is driven off, and a precipitate of carbonate of glucina is formed, the composition of which seems to be 3G10,COV5HO; but if we arrest the boiling as soon as the solution becomes turbid, we obtain a solution of a double carbonate of glucina and ammonia, from which, by the addition of alcohol, this salt is deposited in clear crystals. Double carbonate of ghtcina and cmunonia is white, very soluble in cold water, but is easily decomposed by hot water, liberating carbonate of ammo- nia and depositing carbonate of glucina. It is much less soluble in dilute alcohol, and nearly insoluble in absolute alcohol. It is easily decomposed by heat, leaving as a residue pure glucina. It is also decomposed by exposure to the air after some time. According to Debray the formula of this salt is 4G10,3CO-HO + 3(NIP0,C0^). There also exists a double carbonate of potash and glucina corresponding to this salt, and is prepared by the same process, merely substituting carbonate of potash for carbonate of ammonia ; the carbonate of potash, however, takes longer to dissolve the glucina than carbonate of ammonia. Oxalic acid dissolves glucina, but does not yield any crystallizable compounds, except in combination with other oxalates, as the oxalate of pota.sh or ammonia. These double salts crystallize well and have the following simple composition : G10,C'05-hK0,C=0'; G10,CW4-NirO,C='Ol These salts are obtained by dissolving carbonate of glucina in binoxalate of ammonia or potash in the cold, until carbonic acid ceases to be given off. They decrepitate by the ap- plication of heat. The composition of glucina is still undecided ; Berzelius regarding it as a sesquioxide, and Awdejew and others as a protoxide. The latter view gives greater sim- plicity in the formula of its compounds, but glucina has no decided analogy to the ordinary class of protoxides, lime and magnesia, &c. — H. K. B. GLYCERINE. Glycerine is one of the products of the saponification of fat oils. It is produced in large quantities in the soap manufactories in a very impure state, being con- taminated with saline and empyreumatic matters, and having a very strong disagreeable odor. In order to obtain glycerine from this source, the residuary liquors are evaporated and treated with alcohol, which dissolves out the glycerine. The alcohol having been sep- arated by evaporation, the glycerine is diluted with water, and boiled with animal charcoal. This process must be repeated several times, or until the result is sufficiently free from smell. It is, however, difficult to obtain pure glycerine from this source, on account of the nature and condition of the ingredients usually employed in making soap, which it is almost impossible to deprive of rancid odor. The compounds of glycerine with the fatty acids constitute the various kinds of fats and oils, but the base does not appear to have the same composition in all. A certain quantity of water appears to separate, and the equivalent of glycerine to be in some fats but halt what it is in others. Thus the glycerine of the palm oil has the formula C^H^O*, and the glycerine of myristine, or nutmeg butter, CH^'O, of which bodies the common glycerine should be the hydrate. GOLD. 571 Glycerine is now obtained in great quantities from palm oil, in the process of purification for candles. It is employed with much advantage to preserve soft-bodied animals. It is manufactured into soap, is administered internally, and is supposed to possess highly nutritive properties. It has been employed in cases of deafness, and in diseases of the throat. By some it is used to preserve collodion plates in a state of sensitiveness for many days. GNEISS may be called stratified, or, by those who object to that term, foliated granite, being formed of the same materials as granite, namely, felspar, quartz, and mica. — Lyell. Gneiss might, indeed, in its purest and most typical form, be termed schistose granite, consisting, liiie granite, of felspar, quartz, and mica ; but having those minerals arranged in layers or plates, rather than in a confused aggregation of crystals. — Jukes. In whatever state of aggregation the particles of gneiss may have been originally de- posited, we know now that it is a hard, tough, crystalline rock, exhibiting curved and twisted lines of stratification, and composed in the main of quartz, felspar, mica, and horn- blende. Mineralogically speaking, it differs from the granite rocks with which it is asso- ciated chiefly in this, that while the crystals of quartz, felspar, &c., are distinct and entire in granite, in gneiss they are broken, water-worn, and confusedly aggregated. Hence the gen- eral belief is, that gneiss or gneissose rocks, are but the particles of granite weathered and worn, carried down by 'streams and rivers, and deposited in the seas of that early period. — Paqe. GOBELIN MANUFACTORY. This establishment, which has been long celebrated for its tapestry, took its name from the brothers Gobelin. Giles Gobelin, a d3-er at Paris, in the time of Francis I., had found out an improvement in the then usual scarlet dye ; and as he had remarked that the water of the rivulet Bievre, in the suburbs of St. Marceau, was excellent for his art, he erected on it a large dye house, which, out of ridicule, was called Folie Gobelins, (Rabelais.) About this period a Flemish painter, whom some name Peter Koek, and others Kloek, and who had travelled a long time in the East, established, and continued to his death in 1550, a manufactory for dyeing scarlet cloth by an improved pro- cess. Through the means of Colbert, minister of Louis XIV., one of the Gobelins learned the process used for preparing the German scarlet dye from one Gluck, whom some con- sider to be Gulich, (who was said to have learned to dye scarlet from one KufTelar, a dyer at Leyden,) and others as Kloek ; and the Parisian scarlet dye soon rose into so great re- pute that the populace imagined that Gobelin had acquired the art from the devil. It is known that Louis XIV., by the advice of Colbert, purchased Gobelin's building from his successors in 1667, and transformed it into a palace, to which he gave the name of Hotel Royal des Gobelins, and which he assigned for the use of first-rate artists, particularly painters, jewellers, weavers of tapestry, and others. — Beckmann. The national manufactory is now alone remarkable for its production in textile manu- facture of some of the finest works of art ; and not only does it excel in the'high character of its designs, but also in the brilliancy and permanence of its colors. GOLD. The mineral formations in which this metal occurs are the crystalline primitive rocks, the compact transition rocks, the trachytic and trap rocks, and alluvial grounds. Sir Roderick Murchisou says, in his chapter 0)i the Original Formation of Gold, in his "Siluria": "We may first proceed to consider the nature and limits of the rich gold- bearing rocks, and then offer proofs, that the chief auriferous wealth, as derived from them, occurs in superficial detritus. Appealing to the structure of the different mountains, which at former periods have afforded, or still afford, any notable amount of gold, we find in all a general agreement. Whether referring to past history, we cast our eyes to the countries watered by the sources of the Golden Tagus, to the Phrygia and Thrace of the Greeks and Romans, to the Bohemia of the Middle Ages, to tracts in Britain which were worked in old times, and are now either abandoned, or very slightly productive, or to those chains in America or Australia which, previously unsearched, have in our times proved so rich, we invariably find the same constants in nature. In all these lands, gold has been imijarted abundantly to the ancient rocks only, whose order and succession we have traced, or their associated eruptive rocks. Sometimes, however, it is also shown to be diffused through the body of such rocks, whether of igneous or of aqueous origin. The stratified rocks of the highest antiquity, such as the oldest gneiss and quartz rocks, (like those, for example, of Scandinavia and the northern Highlands of Scotland,) have very seldom borne gold,; but the sedimentary accumulations which followed, or the Silurian, Devonian, and carboniferous, (particularly the first of these three,) have been the deposits which, in tlie tracts where they have undergone a metamorphosis or change of structure f)y the influence of igneous agency, or other causes, have been the chief now ws, whence gold has been derived." At the Soimanofsk mines, south of Miask, great piles of ancient drift or gravel having been removed for the extraction of gold, the eroded edges of highly inclined crystalline limestones have been exposed, wliich from being much nearer the centre of the chain than the above, are probably of Silurian or Devonian age. It is from the adjacent eruptive )72 GOLD. serpentinous masses and slaty rocks b that the gold shingle c (usually most auriferous near the surface of the abraded rock a) has been derived. The tops of the highly inclined beds a are in fact rounded off, and the interstices between them worn into holes and cavities, as 812 ■■'- "^i^rtiiij l1llli)lllM 11:5.1 lllL'illl! llll>IK\Uli i>> ill.!AUUI \ni if by very powerful action of water. Now here, as at Berezovsk, mammoth remains have been found. They were lodged in the lowest part of the excavation, at the spot marked wi, and at about fifty feet beneath the original surface of overlying coarse gravel c, before it was removed by the workmen from the vacant space under the dotted line. The feeble influence of the streams (n) which now flow, in excavating even the loose shingle, is seen at the spot marked o, the bed of the rivulet having been lowered by human labor from its natural level o to that marked n for the convenience of the diggers. — Murchison. It was from the infillings of one of the gravelly depressions between these elevations, south of Miask, that the largest lump of solid gold was found, of which at that time (1824) there was any record. This " pepita" weighs ninety-six pounds troy, and is still exhibited in the museum of the Imperial School of Mines at St. Petersburg. Report of the production of Gold aince its discover)/ in California. 1848 1849 1850 1851 1852 £11,700 18S3 1,600,000 1854 5,000,000 1855 8,250,000 1856 1,700,000 1857 £12,500,000 14,100,000 13,400,000 14,000,000 13,110,000 Exports of (jold and silver bullion from the United States, fts shown by the annual offi- cial reports on '"' Commerce and Navigation," by the Secretary of the Treasury of the United States. (Prior to 1855, the reports do not show separately the coin from the bullio7i, and in the following years silver is not separated from fjold, but almost the entire amount was undoubtedly goid.) 1855 1856 1857 $34,114,995 28,689,946, of which from San Francisco, $6,947,404 31,300,980 " " " 9,922,257 The gold, the production of foreign countries, imported into the United States for the years ending 30th June, was as follows : Te.ir. Bullion. Coin. 1852 - - - $608,257 - - - $3,049,802 1853 - - - 463,044 - - - 1,962,312 1854 - - - 1,720,711 - - - 1,311,253 1855 - - - 404,217 - - - 688,585 1856 - - - 114,289 - - - 876,046 1857 - - - 151,585 - - - 6,503,051 Shipments of gold from San Francisco colony, to eastern domestic parts and foreign ports, from the San Francisco Price Current : 1853 1854 United St.ntos. §47,916,447titV 46,289,649^ England. $4,975,662T-7fV 3,781,080i%*o Other Countries. $1,913,990 73 1,163,779 78 Total in 1853 «' 1854 $54,906,100-nj^ 51,234,508^ The history of the production of gold in California and the States of the Union, is well told in the following table, showing the deposits of gold in the limits of the United States. These have been supplied for this work by the obliging kindness of Mr. Rockwell, of Wash- insrtoiL GOLD. 573 K) CQ CO 00 r-l CI to lO tH to o ,_, •»*< CI «D o O ■-< 00 t- "-1 00 •«i< o o 03 O CJ C3 CO U3 C» lO CO 1—1 ^ B >o o >o O CO lO rf O CO Tj< It- O 5 CS o" m Jtr- O -f H-1 £- CO 1— 1 CO O ^ H o O Ci t- cj o -H o CI CO « r-l o o SI J.~ i- o CO CO £- to lO o >o c^ co tH lO CO CO ■n , ':)< to , 'CO ■ V5 O ' o ■- -* CI ^ CO o ■rti ^ 2 i! (>1 o .-1 d r- lo t-^ Ir- CO o , , 00 . r-l O . UO lU rH (>J • ' ' ■-! ' -^ ' C3 CO 00 ^ CI to >o -^ to C3 0 C^ rl ' ' CO ^ ■ o> 05 CO o CJ CJ _i ■^ ^ ^ It- CO 1—1 c o (M o 1-1 CO (M lO CO H o o o ira o o — > w M< o O W 1— 1 CO O CI CO , o CJ i-H 02 CI i-l to CO r-l -H ?■; CO \0 l-H Tfl ■rjl C5 lO ir- C3 lO k CO O IQ CJ CO 1-1 *- ■-! '^ CO -f O o I-H co_ cT O JD GO 03 CI oo lO C CO CO CO CO -+ ■rjl OS to CI 1— 1 O t- .a a £ (— > o o o to r- "+ C^ to O O 03 CO |2 _< O o CO m ci CO C3 lo m C5 c^ c) to o o O -ri* ■* to -* CJ .-1 p '— ' o CO •-t n ■"• _^^ o UO i.O c3 m o -H fO d .-1 (M to o t- lo x~ 'ra o G ^ <-> C5 03 00 C5 »o CI O •* OJ o o 00 £r "o ' CO CO CO__ C5_ o to C1_ CO__ ci_ to^ >o_ co" cf co" co" ^"^ CI 1— __ t> i-1 • CI lO CI to o 00 lO CI CI CI t- . . . . . . . • • • ' • o . CO r— I^ r- I 1 i 1 • a 3 r3 r/3 CO 00 on ' ' ' ' • •r; I-t P-i O o o o -* Cf) o ifs >o >o m o *-' CO CO oo GO 00 (» oo 00 CO oo oo CO CO H 574 GOLD. 2. Branch Mint, San Francisco. Period. California. Total 1854 1855 1856 1857 to June 30- Total Dollars. 10,842,281-23 20,860,427-20 29,209,218-24 12,526,826-93 Dollars. 10,842,281-23 20,860,427-20 29,209,218-24 12,526,826-93 73,438,763-60 73,438,763-60 3. Branch Mint, New Orleans. Period. North Carolina. South Carolina. Georgia. Alabama, j California. Tennessee. O""" ToUl. Sources. *"«"• 1838-17 184S 1849 1850 1S51 1852 18.53 1854 1855 1S.56 1857 to ) June 30 j" Dollars. 741 Dollars. 14,306 1,488 Dollars. 37.364 2,317 Dollars. Dollars. 61.903 6,717 1,124 4,062 669,921 3,560 4.575.576 1,040 1 8,769.682 3,777,784 2,006,673 - ; 981.511 411,517-24 - 1 283,;}44-91 - ' 129,328-39 Dollars. 1,772 947 Dollars. 3,613 2.783 894 Dollars. 119,699 12,593 677,189 4,580,030 8,770,722 8.777,784 2,006,673 981.511 411.517-24 283,344-91 129,328-89 Total - 741 16,217 39,681 77,282 21,606,461-541 2,719 7,290 21,750,391-54 4. Branch Mint, Charlotte, North Carolina. Period. North Carolina. South Carolina. California. Total Dollars. Dollars. Dollars. Dollars. 1838 to 1847 - 1,529,777 143,941 - 1,673,718 1848 359,075 11,710 . 370,785 1849 378,223 12,509 . 390,732 1850 307,289 13,000 - 320,289 1851 275,472 25,478 15,111 316,061 1852 337,604 64,934 28,362 430,900 1853 2-27,847 61,845 15,465 305,157 1854 188,277 19,001 6,328 213,606 1855 196,894-03 14,27717 5,817-66 216,988-86 1856 157,355-18 - 15,237-35 173,592-53 1857 to June 30 75,696-47 - - 75,376-47 Total 4,033,189-68 366,695-17 87,321-01 4,487,205-86 5. Branch Mint, Dahlonega, Georgia. Period. North Carolina. South Carolina. Georgia. Tennessee. Alabama. California. «""" 1 Total. Sources, j Dollars. Dollars. Dollars. Dollars. Dollars. Dollars. Dollars. Dollars. 1838^7 64,a51 95.427 2,978.353 32,175 47.711 . - 3,218,017 1848 5,434 8,151 251,376 2,717 4,075 - - 271.753 1849 4,882 7.323 225,824 2,441 3,661 . • 244,131 1^0 4,.500 5,700 204.473 1,200 1,800 80.025 • 247,693 18.51 1,971 3,236 154,723 2,251 2,105 214,072 951 379,309 18.52 443 57,543 93,122 750 - 824.931 - 476,789 18.53 2,085 33,950 56,984 149 . 359,122 . 452,290 18.54 5,818 15,983 47,027 223 - 211,169 . 280,225 1855 8,145-82 9.113-27 66,686-36 . 277-92 47,428-70 . 116,652-07 18.56 - 25,723-75 44,107-99 106-42 - 81,46710 - 101,405-26 1857 to 1 June 30 f - 8,083-89 25,097-63 - - 6,498-02 - 39,679-54 Total - 92,629-82 270,238-91 4,137,773-98' 42,01242 i 59,629-92 1,2-24,712S2 I 951 5,827,948-87 GOLD. 575 6. Assay Office, New York. Period. Virginia. North Carolina South Carolina. Georgia. Alabama. Ten- nessee. California. Other Sources. Total. 1854 1855 1S56 1857 to June SO Dollars. 167 2,370 1,928 [ 1,531 Dollars. 3,916 8,750 805 07 1,639 Dollars. 395 7,620 4,052 29 2,663 Dollars. 1,242 13,100 41,101 23 10,451 Dollars. 350 233 62 1,545 Dollars Dollars. 9,221,457 25,025,896 11 16,529,008 90 9,899,957 Dollars. 1,600 Dollars. 9,227,177 25,054,686 11 16,582,129 16 9,917,836 Total 10,996 10,160 07 14,730 29 65,894 28 i 2,128 62 60,676,319 01 1,600 60,781,828 27 Summary exhibit of the entire Deposits of Domestic Gold at the United States Hint and Branches from 1804 to the ZOth June 1857. Mints. Philadelphia. San Francisco. Nevr Orleans Dollars. Virginia - - 1,479,785 50 N"th Carolina 4,400,373 S'th Carolina 535,492 Georgia - - 2,374,793 50 Tennessee - 85,563 Alabama - - 54,944 New Mexico 48.397 C.tlifornia - 226,839,521 62 Other Sources 95,740 Dollars. Total - - 235,864,614 62 Dollars. 741 16,217 3,963 2,719 77,232 Dollars. 4,033,189 6S 366,695 17 73,433,763 60 21,606,461 54 - 1 7,290 I 87,321 01 Assay Offic Dollars. Dollars. 1,490,781 50 8,537,093 67 1,203,373 37 6,618,142 76 80,299 42 193,934 54 43,-397 1,224,712 82 60,676,319 01 333,873,099 60 951 I 1,600 I 105,581 92,629 82 270,238 91 4,137,773 93 42,012 42 60,629 92 Dollars. 10,996 I 10,160 071 14,730 29 65,894 28 2,123 62 r3,438,763 60 21,750,391 54 4,487,205 86 5,827,948 87 60,781,828 27i402,160,752 76 Australian Gold Mines. — The discovery of the great gold field in Australia to the west- ward of Bathurst, about 150 miles from Sydney, was officially made known in Great Britain, by a despatch from Sir C. A. Fitzroy to Earl Grey, on the 18th September, 1851, many per- sons with a tin dish having obtained from one to two ounces per day. On the 25th of May, he writes that lumps have been obtained varying in weight from one ounce to four pounds. On the 29th of May, he writes that gold has been found in abundance, that people of every class are proceeding to the locality, that the field is rich, and from the geological formation of the country, of immense area. By assay the gold is found to consist of 91" 1 of that metal, and about 8-333 of silver, with a little base metal ; or of 22 carats in fineness. July 17th, a mass of gold weighing 106 pounds was found imbedded in the quartz matrix, about 53 miles from Bathurst ; and much more, justifying the anticipations formed of the vast richne.ss and extent of the gold field in this colony. This magnificent treasure, the prop- erty of Dr. Kerr, surpassed the largest mass found in California, which was 28 pounds, and that in Russia, which was 70 pounds, now in the museum at St. Petersburg. One party of six persons got at the same time £4:00 in ten days by means of a quicksilver machine ; and a party of three, who were unsuccessful for seven days, obtained in five days more than 200 ounces. A royalty of 10 per cent, was ordered to be paid on gold in matrix if found in Crown lands, and 5 per cent, if found in private property. Numerous claims have been made by persons who have thought that they had given the first indications of gold in Australia. To Sir Roderick Murchison is, however, due the merit of pointing out that gold might probably be found in Australia, long before it was known in Europe that gold existed in that important colony. Sir Roderick Murchison thus gives us the facts : " Having in the year 1844 recently returned from the auriferous Ural Mountains, I had the advantage of examining the numerous specimens collected by my friend Count Strzelecki along the eastern chain of Australia. Seeing the great similarity of the rocks of those two distant countries, I could have little difficulty in drawing a parallel between them ; in doing which I was naturally struck by the circumstance that no gold had yet been found in the Australian range, which I termed in anticipation the ' Cordillera,' im- pressed with the conviction that gold would sooner or later be found in the great British Colony. I learnt in 1546 with satisfaction that a specimen of the ore had been discovered. I thereupon encouraged the unemployed miners of Cornwall to emigrate, and dig for gold .as they dug for tin in the gravel of their own district. These notices were, as fiir as I know, the first printed documents relating to Australian gold." August 25th, 1851, Lieutenant-Governor C. J. Latrobe announced to Earl Grey from Melbourne, the discovery of large deposits of gold in that district of the colony. In a sec- ond Parliamentary blue book, issued February 3, 1852, it is stated that 79,340 ounces of gold, worth £257,855 7s., had been previously forwarded to England ; and that the gold 676 GOLD. fields of the colony of Yictoria rival, if they do not exceed in value, the first discovered gold fields of New South Wales ; the total value being then £300,000 ; and but a little time afterwards about half a million sterling. Mr. E. Hargraves, commissioner for Crown lands, announced from Bathurst, that no part of California which he had seen has produced gold so generally and to such an extent as Summerhill Creek, the Turon River and its trib- utaries. For the purpose of conveying a correct idea of the conditions under which the greatest quantity of the Australian gold occurs, three plans have been selected from different dis- tricts. The first of these {fig, 313) represents a longitudinal section along the course of the 313 1. Auriferous drift. 2. Boundary of workings. 3. Boundary fence. 4. Creswick's Creek. west quartz vein in the Clunes gold-mining field. We have here, as indicated by the darker portions of the wood-cut, the quartz vein shown in section, with the shafts sunk, and the levels driven upon it. The lighter portions of the figure resting on the quartzose rock is an auriferous drift ; and on the left of the section the great basaltic formation is shown. 314 °„ I' P 1 5 '; 3 4 cz~ ^ OASALT rc 91A11 1. The town of Ballarat East 2. The main road. 3. The Red Streak-lead. 4. The Creek. 5. Old Post-office Hill, with quartz reef. 6. Basalt escarpment south of Golden Point. 7. White flat recent auriferous alluvial deposit. 8. Tarrowee Creek. 10. The Gravel-Pits lead. Mi '.I aii.l li i.ic trtu ^.liaft? ^uIlk into the ancient auriferous alluvial deposit. 12. Quartz reef beyond the town of Ballarat West, shown in the drawing. B is the remains of a lava stream, interrnjited by the schist and clay slate hills. D D is the gravel strata which invariably rests on the side of the schist hills which surround the Ballarat basin. Fig. 314 is a section of a portion of the Ballarat gold field. It is an east and west sec- tion from the Red Streak-lead across Post-office Hill, White Flat, the township of Ballarat West, and the quartz reef west of the township ; and it shows the auriferous drift, schist, quartz, and basalt fornrations of the district. In those two sections, we have, therefore, all the conditions shown of the processes of mining on the quartz lodes and in the alluvial deposits. Fig. 315 is a section from the Eoroondara and Bulleen gold mines, a few miles from the capital of Victoria. It is the east and west section of the Carlton Estate quartz reef, and is mainly given to illustrate the unskilful and dangerous condition of many of the workings undertaken by men who have no experience in subterranean operations. The shaft, if such it can be called, is about 40 feet deep ; and the reef dips with the solid strata at an angle of about 60 degrees to the horizon. The wall of the shaft at a is not supported on the footwall by props and proper timbering, GOLD. 577 which it should be, as indicated by e e e. both exceedingly insecure. This is the mode of proceeding in a very important working, where almost every piece of quartz broken out contains gold, and also antimony and iron. At the point f the quartz reef was exceedingly rich, and there it branches off into small strings, yield- ing 22 ounces of gold to the ton. It is not necessary here to trace the progress of gold-mining in this colony. The quantity of gold dis- covered and exported has been enormous. Some exceedingly large " nuggets " have been found ; one in Forest Creek, weighing 27 lbs. 6 oz. 15 dwts. and the Welcome Nug- get, weighing 2,217 oz. 16 dwts. The produce of the gold fields of Victoria in 1856 was as follows : — The quantities brought to Melbourne and Geelong by escort, From Castlemain and out-stations " Sandhurst and do. .... " Maryborough and do. .... " Ballarat and do. .... " Beechworth and do. . - . - Brought by private hand Quantity which has evaded duty In the treasury banks at camp, &c., and in transitu Total The windlass at c and the framework at d are Oz. - 872,897 - 599,100 - 327,709 - 1,009,822 - 334,709 2,644,237 - 824,322 59,411 - 419,190 3,947,160 oz. The exports of gold from Australia since 1851 have been as follows : — Value. Value. 1851 1852 1853 1854 - £907,113 - 9,735,903 10,445,700 - 9,028,759 1855 1856 1857 £11,513,230 12,740,480 11,764,299 The quantities of gold exported from New South Wales alone in the same periods have been : — Quantities. Value. 1851 - 1852 - 1853 - 1854 - 1855 - 1856 - 1857 to 31st March ozs. dwts. grs. 144,120 17 16 818,751 18 17 548,052 19 21 237,910 13 23 64,384 14 3 42,463 17 1 17,088 8 £ s. d. 468,336 2,660,946 1,781,172 773,209 209,250 138,006 64,081 10 1,872,773 9 9 6,095,000 10 The remainder being the produce of the gold fields of Victoria. Gold has been discovered in some considerable quantities in Tasmania. It has been reported as having been found, although as yet not to any great extent, in New Zealand ; and it is well known that this precious metal is found in all the islands of the eastern Arch- ipelago. The rtccnt discoveries of Gold in British Columbia. — The following communication from a corresponden tto the Victoria Gazette, Vancouver's Island, is especially interesting. It is dated Upper Fraser River, Nov. 28, 1858. Magnitude of the Gold Fields of British Columbia. — " That the auriferous deposits of Vol. III.— 37 578 GOLD. this region are spread over a considerable scope of country is apparent from the fact that paying diggings have already been found on the Fraser River, extending from Fort Hope almost to Fort Alexander, a continuous distance of nearly 400 miles. Among the trib- utaries of this stream, Thompson and Bridge Rivers are known to be auriferous — the latter sufficiently so to have already richly rewarded those who have labored upon it as high up as 35 or 40 miles from its mouth, while the former has been ascertained to have many bars that will pay in its bed. On two of its confluents — Nicholas and Bonaparte Rivers — good dig- gings are reported to have been recently discovered. How many more of the numerous branches of these streams shall yet be found abounding in gold remains to be seen, little or no prospecting having thus far been done upon them. Kor is tlie extent of this gold field likely to be limited to these rivers and their sources. Coarse gold was found about six weeks since by some packers while exploring for a mule route around Lake Seton. It was discovered on a large creek flowing into the outlet of the lake at a point about 15 miles from the Fraser. The dust was apparently of high standard value, at two places on the Lillooet River bars having been found that will warrant working with a sluice. The first of these is on the east side of the stream, 10 miles above Port Douglas, where a party are now washing with sluices with very satisfactory results. When I passed the spot they had been at work but two days ; the first day three men took out $14 50c., the next day, §18. They showed me the gold, which was fine, like that found on the Lower Fraser. The other bar is 20 miles above Port Douglas. It is very extensive, and promises to pay as well as the one first named, though it has not yet been worked. Bars similar to these are abundant on the Lillooet, and the fact of these having been prospected was owing to the accident of a log cabin having been built near them, and not because they seemed more likely to contain gold tlian the others. For 100 miles above the Pavilion, and beyond what is termed the Canoe Country, the banks of Fraser River have been proved to pay even better than below, the gold being coarser and more easily saved, as well as more plentiful. It will thus be seen that the gold fields of British Columbia, ascertained to be paying, to say nothing of rumored discoveries beyond, are tolerably extensive. They do not, it is true, rival those of California or Australia in magnitude ; but that they cover a large scope of country, and will give employment to a large population, is settled beyond controversy or question." Richness of the Mines. — " To claim that the Fraser River mines are as rich, or that labor has been generally as well rewarded in them as in the mines of California at an early day, would be idle. I might say much in explanation of the numerous failures that attended the first adventurers to these mines, without making myself their apologist — how the miners came too soon and in too great numbers — how the river kept up, and of the many disadvantages under which they laJDored ; all might be enlarged upon were it not now well known to the public. In regard to this section, however, I may say those pioneers who worked here last winter and spring uniformly made large wages ; and that those who came in since have been able to remain, paying the enormous prices they have done for pro- visions, proves that tliey must have had good paying claims most of the time. The cost of living here, with other necessary expenditures, could not have been less than $4 a day to the man, vet I find all have been able to defray their current expenses, while many have accumulated large sums — sufficiently large in a majority of cases, with those who have been here any length of time, to lay in a winter's stock of provisions, even at the present high prices. That better average wages can be made here than in any part of California at pres- ent there is no doubt. This can be done even with the present want of ditches and indif- ferent appliances for taking out the gold. These diggings, owing to the fineness of the dsst and the difficulty of saving it, require to be worked with sluices — a mode that has been introduced to but a limited extent as yet, owing to the want of lumber as well as of wheels or ditches for supplying water. When sluices shall have been generally brought into use, more than twice the amount now realized can be taken out to hand. Anotlier cause that will tend to render these mines highly remunerative in the aggregate is, that every man will be able to secure a claim, and that"^but little capital will be required for starting opera- tions ; hence evei^ one will enjoy the full fruits of his own labor, and none need remain idle. For this winter, owing to the lateness with which provisions have been got in, not much will be done ; no one here expects it ; the utmost that will be aimed at, as a general thing, will be to make enough to pay expenses of living, to prospect a little, and be on hand at the breaking up of winter. With the coming of spring large operations will be entered into, and all here entertain the most sanguine anticipations, or rather, I should say, fullest confidence as to the results." Tfieir durability. — " That these mines will be found not only rich and extensive, but also lasting, I am fully satisfied. Apart from their vast extent of surface, the diggings, at one time thought to be shallow, are now known to run downward in n>any localities to a good depth. It has lately been ascertained that not only the bars along the river, but many of the lower benches or table lands, contain sufficient gold to pay where water can be brought upon them, which in most cases can easily be done. These benches are not only numerous, but often of great extent, and would afford employment for a large number of GRINDING AND CRUSHING MACHINERY. 579 men for many years to come. Little or no search has been made as yet for drift diggings or quartz, though there are abundant indications that both, of a paying ciiaracter, exist. Fine ledges of quartz, in fact, present themselves almost everywhere, though no thorough examination has been made of their quality. The banks of Bridge River consist of alternate strata of slate and quartz rock, the most favorable possible geological formation for gold. I would venture, then, after having seen considerable of the mines in this quarter, to express the confident opinion that they will prove sufficiently extensive, productive, and lasting, to warrant a lar"-e immigration to this country in the ensuing season, and that British Colum- bia is destined to become another great gold-producing region, ranking next to California and Australia in the amount slie will hereafter annually yield of this precious commodity." Such is a general view of the gold-producing districts of the world. Much fear has been expressed lest the influx of gold saould reduce the value of that metal. Since the discov- ery of the Californian gold field in 1848, not less than £159,807,18-1 sterling has been added to the wealth of Europe and America from the great gold fields of California and Australia. Tills question cannot be discussed in this place, but it is one of the greatest interest, de- manding alike the consideration of the politician and the social philosopher. GOLD THREAD, or spii. When it is required to change the rollers, the pressure resulting from the lever a and weighted box E, is relieved by means of the screw-tackle f. The considerations which should be attended to in constructing a crushing-mill, are, fii-st to make all the parts sufficiently strong to meet the varying resistance's which contin- ually occur in crushing. For this purpose, the frame-work to receive the rolls ought to be of good cast iron, the axles of the rollers of best wrought iron, and the cylinders of the hardest and most uniform metal. 2dly. To design the machine so that the matter to be crushed may be readily delivered into the hopper, sized by the circular sieves for the dress- ing process, and such portions as are not properly crushed, returned to the rolls without the int€rvention of manual labor. In order to effect this, the inverted, or raff wheel d, /y. 318, GRINDING AND CRUSHING MACHINERY. 581 shown in section, ought to be made of sufiBcient diameter to allow the stuff, on being dis- charged, to descend by its own gravity into the feed-hopper. 3dly. To extend from the axis of the rollers, long tumbling shafts, a i.,fig. 318, and fix on their ends the driving 318 wheels b b, allowing a little play in the plummer blocks, so that any undue opening of the rolls may not vary the pitch line of the wheels b b, to such an extent as to endanger the safety of the teeth. 4thly. To construct the roll so that it may be readily changed, yet maintained on its axis without slipping when in motion. One of the most efficient plans for this purpose, is shown in the following wood-cut, in which a is the axis or arbor, and d the roil. 319 Ct^3C ^Q It will be seen that the cylinder roll is fitted with four internal projections ; these are of the same length as the portion of the groove marked b b', but no wider than the nar- rower part of the groove c. When the cylinder is to be fixed on the axis, the studs are introduced into the recesses c, and the cylinder advanced into its working position, when it is turned until the studs fit into that portion of the recess between b b', and which are then wedged to the roll by a close-fitting cutter. 5thly. Tlie diameter of the rolls should be decreased, and the length inn'eased in pro- portion to the fineness of the stuft" to be crushed, since a fine material requires a longer line of contact, and not so large a grip as coarser substances. In practice it has been found advantageous to make the roller placed on the driving sliaft somewhat longer than that which is opposite, and to work the roils by spur gearing rather than by friction, since the latter is proved to furnish less economical results than the former. It has also been found injudicious to harden the rolls by chilling ; hence ordinary sand-cast rolls are most frequently employed. Tiie speed of the rolls varies from 45 to 60 feet per minute, but this necessarily differs with the character of the stuff to be crushed. Again great variation is experienced in tiie quantities crushed witliin a given period, since a small amount of moisture in vein stuff of a certain class makes it cake, and will thus considerably reduce the produce of the mill. On the other hand, if the matter operated upon be very dry, heavy, and brittle, as in the case 582 GRINDING AND CRUSHING MACHINERY. of some varieties of lead ore, the produce may be much increased, since the mill can be driven at a great speed ; a less bulk will have to pass for a given weight, and there will be a smaller quantity of material carried back by the raff wheel to be recrushed. Variable speeds have sometimes been tried in order to produce friction together with pressure at the line of contact, but it has been found that any departure from a uniform speed on the two surfaces, absorbs a considerable additional amount of power, without ma- terially augmenting the results. Arrastre or ta/iona. — This machine is extensively employed in the mining districts of Mexico, lor grinding silver ores previous to their amalgamation. It consists of a strong wooden axle a, (Jiff. 320,) moving on a spindle in a beam b above 320 i^^^ k 5 ■^r^^3i~^^'^^7\Z it, and resting on an iron pivot beneath, turning in an iron bearing, which is inserted into a post of wood c, which rises about a foot above the ground in the centre of the arrastre. The shaft a is crossed at right angles by two strong spars n d, which form four arms, each about 5 feet long, one excepted, which is 9 feet long, to admit of two mules being attached to it; by this arm the machine is worked. The grinding is performed by four large porphy- ritic or basaltic stones, two of which are shown, e e. These are loosely attached by thongs of leather, or small-sized rope, to the four arms, and are dragged round over the ore, which is put in with water, until it is ground to a very fine slime or mud, called the lama. One of these machines, wlien in good working condition, will grind from 600 to 800 pounds weio'ht of ore in twenty-four hours. In Guanaxuato, where the best and finest grinding is obtained in the arrastres, the lining or foundation and the grinding stones arc, of course, grained porpliyry. and form a rough surface. The cost of this apparatus in Mexico, includ- ing the paving of the bottom, and the four vietapiles or stones, is on an average £7. The original weight of a mctapile is about 700 pounds, its dimensions are 2 feet 8 inches long, 18 inches broad, and 18 inches deep. Notwithstanding the hardness of the stones em- ploved, they are so worn as to become unserviceable in the course of ten or twelve weeks ; the bottom, however, is only rcjilueed once in twelve months. This apparatus is well suited to patio amalgamation, but it affords bad results for the power expended. Edge mill. — Tiiis machine is employed for the purpose of reducing gold and silver ores to an impalpable powder. It is also used extensively in grinding Hints, stones, slags, and a varietv of other products. However much the details of this apparatus may vary, its prin- ciple is the same in all cases. Two vertical runners rotate on the outer circumference of a flat or slightly conical basin, and afford a frictional or grinding area equal to the difference of distance performed bi) the innrr and outer edges. The subjoined wood-cut, /?(/. 321, represents a mill constructed at the Mould Foundry, Flintshire, a, rotating pan, resting upon frictional wheels b ; c. vertical shaft firmly keyed to pan A, to which motion is communicated by wheel gearing n. The runners e e revolve on arm F, and may be of cast iron or of stone bound with a ring of iron. These runners have no progressive motion, but have free play to rise or fall on axis c, and in the stay slots G G. GRINDING AND CRUSHING MACHINERY. 321 583 The following dimensions and particulars are derived from one of the edge mills recently working at tlie Fabrica La Constante in the province of Guadalajara, Spain : — 6 feet. Centre 20 in. edge 16 in. 3 tons, 15 cwt. 200 feet per minute. 4 feet. 10 holes to the lineal inch. 60 " " 350 lbs. 7. Diameter of edge runner . . . - Width of do. do. . . . - Weight of do. do. .... Speed of runner -..--- Diameter of interior circle of runner Gauge of stuff" previous to its being ground - Do. after it leaves the mill - Quantity of stuff" reduced per 10 hours - Horse power employed - - - - - In some machines erected at the Real-dcl-Monte mines in Mexico the stones were 6 feet in diameter and 12 inches wide. They were fitted with a ring of wrought iron 3 inches thick. Each pair of runners revolved round a centre on its own a.xis, in a cast-iron basin of which the l)0ttom was 7 inches thick. At first good results were obtained: each mill, if kept constantly at work, ground nearly ten tons per week ; but as their axles, and partic- ularly the wrought-iron rings and cast-iron bottoms, began to wear hollow, and to lose an even surface, the grinding rapidly diminished, and with one year's work they were com- pletely worn out. The chief advantage of this macliine is its simplicity of construction and consequent small first cost ; but all its parts require to be made of great strength, and therefore of pro- portionate weight ; hence, in addition to the rapid wear to which it is liable, this appanittis becomes objectionable for countries where transit of heavy machinery is more than ordi- narily difficult and expensive. Horizontal inUl. — For the purpose of reducing auriferous and argentiferous ores to an exceedingly fine powder, and where dry grinding is essential, no apparatus has been found more eff'ectual than the horizontal mill. It affords the largest area of frictional surface for 584 GRINDING AND CRUSHING MACHINERY. the least wear and tear, and accomplishes equal results at a cost not exceeding one-fourth of that incident to the edge mill. The construction of the horizontal mill will be rendered intelligible by the aid of the following illustration, fg. 322, in which one pair of stones is shown in section, a is a cir- 4. m. S ' im: cular hopper, into which the stuff to be ground is introduced ; b b, small pipes of sheet iron, for delivering the stuff between the surfaces of the runner c and bed-stone c' ; d, cas- ing enclosing the runner into which tlie ground material is delivered ; e, hole in centre of runner ; f, driving shaft, with continuation shaft g, for giving motion to a Jacob's ladder if requisite ; ii h', regulating screw for elevating runner c ; j, driving wheel ; k, crown wheel ; l, wheel giving motion to pinions m m' ; and k, vertical shaft, to drive any supple- mentary apparatus which may be requiring such, as sizing sieve, &c. Four pairs of stones are usually driven by the wheel l. The surface of the runner is in contact with the bed- stone, from the periphery to within one-third of its diameter. The line of the runner then feathers upwards, in order to receive the stuff freely, and to equalize the resistance through- out the area of the bed-stone. The following particulars will convey much practical infonnation rclntive to this machine : Diameter of stones . . . - Thickness of bed-stone - - - - Ditto runner .... No. of revolutions of stone per mmute - Gauge of stuff in stopper Ditto on delivery Quantity of stuff ground per 10 hours - Power employed in horses ... Revolutions of sizing sieve ... Diameter of ditto .... Length of ditto - No. of holes per square inch in sizing sieve 4 feet 2 inches. 12 inches. 14 inches. 108. 100 holes to the square inch. 3,600 ditto 1 ton per pair of stones. About 5 per ditto. 23 per minute. 30 Inches. 108. 3,600. GRINDING AND CRUSHING MACHINERY 585 Character of runner Coarse conglomerate. Ditto bed stone Compact quartz, moderately hard. Duration of runner Average 18 weeks. Ditto bed-stone Ditto 22 ditto. When dressed Every third day. From a series of practical experiments made on the same stuff by these several mills the following results have been obtained : — No. of Holes per square inch in Sizing Sieve. Quantity of Stutf gi-oiind in 10 hours. Horse Power. Cost ptT ton 1. Horizontal mill 2. Crushing mill - 3. Edge mill 3,600 3,600 3,600 Cwts. 20 13 13 5 5 7 « d. 2 3 1 7 6 10 J. D. MackwortlCs Patent Crmhing Rollers, Jigs. 323 and 324, for Coal and other Minerals. These rollers are made conical to equalize the wear, and as one roller travels faster than the 323 586 GUANO. other, the fragments are partially turned over, so as to present their weakest line of fracture to the direction of the crushing" force. Less power is required to work these rollers. In lieu of the counterbalance weight usually employed to allow the rollers to separate and pass excessively hard fragments, and to bring the rollers together again, the machine is made more compact, and simplilied by connecting 2 brass collars, in which the rollers work by a number of bands or cords of vulcanized india-rubber strongly stretched. A compound cord of india-rubber, 3 inches in diameter, composed of 144 small and separate cords, when stretched to double its natural length, gives a strain of 3 tons. The brass collars do not revolve. GUANO. This extraordinary excremcntitious deposit of certain sea-fowls, which occurs in immense quantities upon some parts of the coasts of Peru, Bolivia, and Africa, has lately become an object of great conunereial enterprise, and of intense interest to our agricultural world. More than twenty years ago it was exhibited and talked of merely as a natural curiosity, but since that time the quantity imported into England alone has risen from 30 000 to 300,0U0 tons, (in 1855,) the value of which was estimated at no less than £3,000,000. . .^ ^ Natural History ami Geography.— Euano, in the language of Peru, signifies dung ; a word spelt bv the Spaniards, guano. The conditions essential for the preservation of these excrements appear to be the exist- ence of a soil consisting of a mixture of sand and clay, in a country where the birds are allowed to live for ages undisturbed by man or man's works, and where, moreover, the cli- mate is very drv, free not only from rain, but also from heavy dews. These conditions appear to have been combined to a remarkable extent on the coasts ot Peru and Bolivia, between latitudes 13° north, and 21° south of the equator, for although beyond this region the flocks of cormorants, flamingoes, cranes, and other sea-fowl, appear to "be equally numerous, vet the excrement is rapidly carried away by the ram or dew. ■ It is then the dryness of the climate chieflv which has permitted the guano to accumu- late on these coasts, for, savs Mr. Darwin : * " In Peru, real deserts occur over wide tracts of country. It has becom'e a proverb that rain never falls in the lower part of Peru " And again : " The town of Iquique contains about 1,000 inhabitants, and stands on a little 825 plain of sand at the foot of a great wall of rock, 2,000 feet in height, the whole utterly desert. A slight shower of rain falls only once in very many years." Indeed since three- fifths of the constituent parts of guano are soluble in cold water Prof. Johnstone very justly * Besearclies in Geology and Katural History, p. 42S. GUANO. 587 observes that,* *' A single day of English rain would dissolve out and carry into the sea a considerable portion of one of the largest accumulations ; a single year of English weather would cause many of them entirely to disappear" Such being the case, we might expect to find similar accumulations in other hot and dry climates, as in Egypt, and in Africa, e. g., in the neighborhood of the great desert ; and only a few years since a considerable deposit of guano was found in the Kooria Mooria Islands. The export of guano from the Cincha Islands has increased considerably during the last few years : between 300,000 and 400,000 tons are the annual amount at present, which is effected by the aid of 900 working hands, 320 of them being Chinese, who enter into con- tracts to serve their employer (the Government contractor) Don Domingo Elias, for 4 dol- lars a mouth, renewing it, if they choose, with the increase of 4 dollars monthly, and a bonus of 120. Those who work on their own account are paid 8 and 10 rials, 4 and 5 shil- hngs, for each cart that they load. They live in a collection of dirty huts made of bamboo and mud ; they, nevertheless, appear to be happy and contented, and in general are well conducted. The men with pickaxes work their way into the guano, leaving a sort of wall on either side, {fip. 325 ;) here it is so hard that it requires a heavy blow to remove it. It is then conveyed "in wheelbarrows either direct to the mouths of the shoots on the edge of the cliffs, or to the huge carts running on tramways for the same purpose. The color varies very much — in some parts being as dark as warm sepia, and in others as light as that of a Bath brick. The smell of ammonia is said to be very powerful, so much so, in fact, as to affect the eyes of the workmen ; crystalline deposits of various ammoniacal salts are also found amongst the guano. The guano heaps are surrounded by a high fence to prevent its being blown away by the wind, near the mouths of the canvas tubes or shoots, which are some- times TO feet long, through which it is conducted to the boats. See Jig. 326. 326 As in Peru, the surface of the guano is covered with skeletons of birds, and bones of seals. It is also perforated by numberless holes, running in every direction, like a rabbit warren. These are made by a bird about the size of a pigeon, which remains iiidden during the day, sallying forth at dark to fish. Gold and silver ornaments are also discovered occa- sionally, having been buried by the ancient inhabitants more than three centuries ago. It is quite unnecessary here to insist on the value of guano as a manure. This is a point established beyond all question by nearly every agriculturist in the kingdom ; and recorded by all classes of writers on agricultural subjects ; it has been the means, moreover, of converting the sandy desert around Lima into a soil capable of raising abundant crops of maize ; hence the Peruvian proverb, " Iluano, though no saint, works many miracles." * On Guano. Journal of tho Agricultural Society of England, vol. ii. p. 815. 588 GUANO. Commercial varieties. — The following appear to be the chief : — 1. Peruvian. 5. Saldanha Bay 2. Angamos. 6. Kooria Mooria. 3. Ichaboe. 7. African. 4. Patagonian. 8. Indian. Chemistry. — Guano being an article of so great value to the agriculturist as a manure, and being liable not only to adulteration to a very great extent, but also varying when genuine considerably in quality, it is highly important to have some means of ascertaining its value. Tliis cannot be done satisfactorily by ever so experienced a dealer by mere inspection, and, therefore, both for the buyer and the seller, resort is necessary, for a knowledge of its com- pound parts, to the analysis of the chemist.* Such being the case, we must first ascertain the composition of genuine guano, and then inquire upon which of its several constituents its value as a manure depends. The constilution of guano is exhibited by the following analysis of three sorts by Den- ham Smith. American GfAXO. — Analysis of three sorts by Denham Smith. 1. Constituents soluble in hot water, {in 100 parts of guano.) I. II. III. Phosphate of lime 0-186 . 0110 Phosphate of soda 0-120 Phosphate of ammonia and magnesia - 0-564 0-784 0-133 Uric acid 2-516 Urate of ammonia 15-418 Organic matter 1-180 0-860 0-756 2. Constituents soluble in cold water, (in 100 parts.) I. II. III. Water Sulphate of potash Sulphate of soda ------ Phosphate of potash Phosphate of soda Phosphate of ammonia . . - - Phosphate of lime Oxalate of ammonia Oxalate of soda Chloride of potassium Cidorlde of sodium -..-•- Chloride of ammonium - . . - Organic matter 22-200 8-00 6-S3 7-40 2-55 1-500 20-420 23-944 7-732 6-124 9-39 0-668 7-700 19-177 4-947 3-60 10-563 4-163 28-631 3-030 2-553 8. Constituents insoluble in ivater, («i 100 parts.) I. II. III. Phosphate of lime 19-750 6-270 13113 Phosphate of magnesia - . - - 2-030 0-874 2-580 Oxalate of lime 2-560 10-958 Sand, &c. - 15-60 0-720 0-420 Peroxide of iron and alumina - - 0-150 Humus 2-636 0-862 0-836 Organic matter ------ 3-456 Water - 4-974 Loss 0-044 0-498 Valuable as these elaborate analyses are in a scientific point of view, they are quite un- necessary for practical purposes in ascertaining the value of any given sample, for on which of these various constituents does the chief efficacy of guano depend ? * liebig's "Chemistry in its applications to Agriculture and Physioloiry," p. 272. GUANO. 589 Ammonia. — Undoubtedly one 0/ ian acid consequently may be preserved of uniform strength, in well filled and closely stoppered bottles, for almost any length of time. The deadly nature of prussic acid unhappily causes it to be only too frequently resorted to by the despairing or the mur- derer. Fortunately, however, in spite of its volatility, the chemist possesses excellent means for its detection. Preparation. — 1. Hydrated acid. As prussic acid is largely employed in medicine, but in a very dilute form, it is usual to prepare it and dilute until of the proper degree of strength. The following process for preparing it will be found to give a satisfactory re- sult, and, moreover, it may be performed on any quantity of materials. The apparatus for the purpose will vary with the scale on which the experiment is to be made. If on a few ounces, glass retorts and flasks answer well, if good condeq^ation is insured by means of a Liebig's condenser well supplied with very cold water. If a large quantity of prussic aoid is to be made, such as several gallons, the apparatus should consist of a stoneware still, with head adjusted by grinding. The head should be capable of adjustment with a stone- ware adapter to a worm of the same material enclosed in a tub of water. The joints are to be luted with a mixture of one handful of almond meal and five handfuls of linseed meal, worked with water to the consistence of putty. A solution of rough chloride of calcium in water is to be made and placed in a large iron pot, with a cover so contrived as to permit the still to drop in up to the flange. 10 parts of yellow prussiate of potash are then to be bruised in a mortar and mixed with dilute sulphuric acid prepared by adding 6 parts of sulphuric acid (density 1'850) to 42 of water. The head being luted on, a fire is to be kindled in the furnace under the iron pot, and the chloride of calcium bath is to be kept boiling constantly until 3(j parts of acid have distilled over. The beak of the .-^till should be placed in the funnel which conducts the acid to the Winchester quart bottles which are to contain the product, and a piece of wet bladder is to be stretched over the funnel to prevent evaporation of the acid into the laboratory. The worm used lor the pur- pose must be ascertained to be perfectly clean, and, if prussic acid is to be frequently made, should be kept specially for that operation. To each Winchester quart of the acid distilling over, one drop of sulphuric acid may be added to insure its keeping. But the acid thus prepared generally keeps for a long time even without this precaution, owing probably to small traces of the sulphuric acid being carried over during the dis- tillation. It is quite impossible to conduct the operation so as to yield a product of unifoim strength ; it is absolutely necessary, therefore, to determine the percentage of real hydro- cyanic acid, and dilute it to the required degree. It fortunately happens that 1 grain of hydrocyanic acid yields almost exactly 5 grains of cyanide of silver ; for one eciuivalent of acid = 27 produces 1 equivalent of cyanide of silver = 1!>4 ; so that 27 : 134 : : 1 : 4'9fi. The acid produced will have, probably, to be reduced to one of two standards ; namely, the so-called Scheele'a strength, containing 5 per cent, of acid, or the P.L., containing 2 per cent. ; 100 grains of the former should, consequently, yield 25 grains, and Itio of the P.L. 10 grains of cyanide of silver. In either case the calculation becomes obvious. 2. The anhydrous acid. Several processes for conducting this dangerous operation are known ; the following is, perhaps, the most generally convenient. A large glass retort is 80 arranged that its neck is directed upwards at an angle of about 45° ; a cork fitted to the HYPOCHLOROUS ACID. 605 aperture in the neck connects a glass tube with a bottle containing a little chloride of cal- cium. From the latter vessel another tube proceeds to a U tube containing fragments of chloride of calcium, and from the latter a third, conducting the dehydrated vapor of prus- sic acid to an upright glass tube contained in a mixture of ice and salt. Into the retort is placed a mixture of 10 parts of yellow prussiate of potash, 7 of oil of vitriol, and 14 of water. The retort is to be heated with a ciuucoal fire, and the temperature of the bottle and U tube, containing the chloride of calcium, is not to be allowed to fall below 90% in order to prevent condensation of the anhydrous prussie acid taking place anywhere except in the tube contained in the freezing mixture. The vapor of anhydrous prussic acid is so dangerous that the greatest precaution must be taken to prevent inhaling the smallest portion. Detection of prussic acid. — When prussic acid exists in moderate quantity in a solution it may be detected by first adding a few drops of potash, then a mixture of protosulphate and persulphate of iron, and finally a little hydrochloric acid ; a bright blue precipitate in- dicates the presence of the acid. A much more delicate test, and one that is applicable when, from the dilution of the solution, the salts of iron are no longer capable of acting, is by the conversion of the prussic acid into sulphocyanide of ammonium. For this pur- pose the prussic acid is to be warmed on a watch-glass with a drop of sulphide of ammo- nium, until the solution has become colorless. The addition of a trace of a solution of a persalt of iron will show, by the formation of a blood-red color, the presence of the acid sought. A very neat mode of applying this test is to place one drop of sulphide of ammo- nium on a watch-glass inverted over another containing the suspected fluid. On leaving the apparatus in a warm place, arranged in this manner, for a short time, the upper glass will be found to contain sulphocjiiuide of ammonium, which, after drying, will be in a state well adapted for showing the reaction with a persalt of iron. — C. G. W. HYDRODYNAMICS. The mechanical science which treats of the motion of fluids. This science has, of course, most important bearings on the pumping-engines, water-wheels, &c., employed to facilitate the operation of the miner. It is not, however, possible to embrace this, which belongs to mechanical engineering, in this work. HYDRO-EXTRACTOR. A name sometimes given to the machine employed for ex- pelling the water from woven goods. HYDROFLUORIC ACID. It was observed by Scwankhardt, in 1670, that fluor spar and oil of vitriol would eat into glass. Scheele, in 1771, determined that this peculiar property was due to the liberation of an acid from the fluor spar. Hydrofluoric acid is best obtained by placing finely powdered fluor spar in a leaden retort, and twice its weight of highly concentrated oil of vitriol. By a gentle heat the gas is distilled over, which must be collected in a leaden tube, in which, by means of a freezing mixture, it may be condensed into a liquid. If a solution of this acid in water is required, the extremity of the tube from the retort is carried into a vessel of water. Hydrofluoric acid attacks glass with great readiness, by acting on its silica. Glass upon which any design is to be etched, is covered with an etching wax, and the design made in the usual manner ; this is placed over a leaden vessel, in which is a mixture of fluor spar and oil of vitriol ; a gentle heat being applied, hydrofluoric acid escapes, and immediately attacks the glass. HYDROPHANE. A variety of opal which readily imbibes water, and when immersed it becomes transparent, though opaque when dry. It is found in Hungary, and in Ireland, near the Giant's Causeway, and at Crosreagh, Ballywillin. HYDROSTATICS. The science which treats of the equilibrium of fluids, and of the pressure exerted by them. In the engineering arrangements by which water is supplied to towns, hydrostatics be- comes of the utmost importance. The highest possible level is obtained for the reservoir ; and from this a series of pipes is arranged through all the streets and houses. Tlio tenden- cy of the water is to rise to its original level, and hence all the pipes are filled witli water, and in all such as are below the level of the water in the reservoir a pressure upwai-ds is exerted equal to the height of the reservoir above that point ; and if a hole is pierced in the )»ipe, the water jets out with a force equal to this pressure. In the highest houses, the water perha})s only finds its level, and flows out without pressure quickly. See Water PuEssuRE Machinery for Mixes ; Hydraulic Cranes. HYPOCHLORIC ACID. C10\ Eq. 07-5. When finely powdered chlorate of potash is gradually mixed into a paste with strong sulphui ic acid, and heated in a bath of alcohol and water, a yellow gas is disengaged which is this hypochloric acid, or the ])croxide of ililorine. Although of much interest as a chemical compound, it has no use in the arts. Sec Ure^s Chemical Dictionan/. HYPOCHLOROUS ACID. ClOjEq. 43-5. This acid is best obtained by diffusing red oxide of mercury finely divided through twelve times its weight of water, wliich is introduced into a bottle containing chlorine, and agitated until the g;is is absorbed. An oxychloride of 606 HYPOSULPHITES. mercury is formed, which is removed by subsidence. The weak fluid obtained is put into a flask, and heated in a water bath, when the evolved gas is collected in a smaller portion of water, which becomes a pure solution of hypochlorous acid. HYPOSULPHITES. Saline compounds formed by the union of hyposulphurous acid with bases. Hyposuljihate of Soda. — The salts of thehyposulphuricacid are obtained from the hypo- sulphate of manganese, which is itself thus prepared : finely divided binoxide of manganese is suspended in water, artificially cooled, and a stream of sulphurous acid passed through it. The binoxide gives up half its oxygen, becoming protoxide, which unites with the hyposulphuric acid which is formed, producing the soluble hyposulphate of manganese, which is separated from the excess of binoxide by filtration. The following equation rej^resents the reaction : — MnO' + 2S0* = MnO,S'0^ If the temperature were allowed to rise, sulphuric acid would be formed, and not hypo- sulphuric : — MnO= + SO'' = MnO,SO^ The hyposulphuric acid, unlike the hyposulphurous acid, may be obtained in the free state, and its solution permits even of being evaporated in vacuo, until it acquires the density of 1-347 ; but if carried further, it is decomposed into sulphuric and sulphurous acids. The acid is obtained in the free state by adding baryta water to the hyposulphate of manganese ; the soluble hyposulphate of baryta, filtered from the oxide of manganese, and precipitated exactly by the cautious addition of sulphuric acid, and filtered from the pre- cipitate of sulphate of baryta, yields the pure solution of the acid, which may be evaporated in vacuo, as above stated. It has no odor, but a very sour taste. The hyposulphate of soda may be made directly from the manganese salt or from the free acid. . All the hyposulphates are soluble ; they have not as yet met with any commercial appli- cation. Hi/posulphite of Soda. — This salt, now so extensively used for photographic purposes, was first introduced by Sir J. Herschel. It may easily be prepared by the following pro- cess, viz., by transmitting through a solution of sulphide of sodium (prepared by fusing together in a covered crucible equal weights of carbonate of soda and flowers of sulphur) a stream of sulphurous acid until it ceases to be absorbed ; the liquid is then filtered and evaporated, when the hvposulphite of soda (XaO,S"0- + 5110) crystallizes out. Another and perhaps better process consists in digesting a solution of sulphite of soda on flowers of sulphur. The sulphur gradually dissolves, forming a colorless solution, which yields on evaporation crystals of hyposulphite of soda ; the reaction being shown by the following equation : — XaO,SO* + S = NaO,S'0\ The baryta salt may be obtained in small brilliant crystals, by mixing dilute solutions of chloride of barium and hyposulphite of soda. The hyposulphurous acid is incapable of existing in the free state, for almost imme- diately on the addition of an acid to the solution of its salts, it is decomposed into sul- phurous acid, with liberation of sulphur. (S"0' = SO^ + S.) The soluble hyposulphites have the power, in a marked degree, of dissolving certain salts of silver, as the chloride, iodide, &c., which are insoluble in water; forming wuth them soluble salts, whose solutions possess an intensely sweet taste, although the solutions of the hyposulphites alone possess a disagreeable bitter taste. From the above reaction arises the principal value of the hyposulphite of soda, which is used by the photographer to dissolve off from the photograph, after the action of the light on it, all the undecomposed silver salt, thus preventing the further action of the light on the picture. A double hyposulphite of soda and gold is used for gilding the daguerreotype plate, and for coloring the positive proof obtained in photographic printing. This double salt may be obtained in a state of purity, by mixing concentrated solutions of 1 part of chloride of gold, and 3 parts of hyposulphite of soda ; by the addition of alcohol it is precipitated ; the precipitate must be redissolved in a small quantity of water, and again precipitated by alcohol. Its formation is explained by the following equation : — 8(NaO,S'0') + AuCP = 2(Xa0,S^0=') + Au0,S'0-,.3(Na0,S^0^) -f 3XaCl. Tetrathionate of IlyposulphitR of soda and Chlor. soda. gold. of sodium. H. K. B. INDIGO. 607 ILLUMINATION. The numerical estimation of the degrees of intensity of light con- stitutes that branch of optics which is termed Photometry. Bunseri's photometer consists of a sheet of cream-colored letter paper, rendered trans- parent over a portion of the surface by a mixture of spermaceti and rectified naphtha, which is solid at common temperatures, but becomes liquid on the application of a very gentle heat. The mixture is liquefied and painted over the paper with a brush, leaving a round disc of the size of half a crown in the centre uncovered. When a light is placed on one side of the paper a dark spot is observed on the uncovered portion. When another light is placed on the other side of the paper, the spot is still distinctly visible, if the dis- ta°ice of the light is such that the reflected portion from the paper be either of greater or of less intensity than that' transmitted. When the paper is so situated between the two flames that the transmitted and reflected light are of the same intensity, the uncovered spot is no longer visible. It is possible onlv, to compare one light with another ; there is not any arrangement by which we are enabled to express absolutely the illuminating power. Upon the principle of comparison, and comparison only, the following tables have been constructed by the rela- tive experimentalists. The following comparative view of wax and stoarine candles manu- factured in Berlin, which have been deduced from the observations of Schubarth, is of much value. Eelative Consumption Relative Kind of candles, and whence obtained. intensity of in one hour, illuminating light. in grammes. power. i 4's 103-5 7-877 85-20 Common wax candles, of Tann- A 6 s 91-0 7-176 83-20 hanser 8's 100-0 6-562 100-0 (4's 132-7 9-398 92-66 Wax candles, of Walker - ]6\s 120-3 8-082 97-69 J 8's 1131 7-132 104-1 ( 4's 117-4 9-4-27 81-74 Stearine candles, of Motard \ 6's 111-8 9-383 78-23 (8's 121-0 7-877 100-7 \ '^'^ 139-5 10-63 86-11 Stearine candles, of Magnet and •J ti's 132-7 9-398 92-66 Oehmichen - - - - ( 8's 125-0 8-506 96-54 Stearine candles, from the same \ G's \ 8's 116-1 8-871 85-86 makers 146-0 8-886 108-0 (4's 1-24 -5 9-880 82-67 Candles made from palm oil )6's 115-3 9-178 82-56 (8's 167-5 8-813 113-70 These results show us that the mean illuminating power of wax and stearine candles is nearly the same. INDIGO. We are indebted to Dr. Roxburgh, for a description of the method em- ployed for manufacturing indigo from the Nerium tinctorinni or Wrightia tinctorio. (Vide Transactions of the Society of Arts, vol. xxviii.) This plant, which attains the size of a small tree, is found on the lower regions of the mountainous tract near Rajamundry, and also on hills in tlie neighborhood of Salem and Pondicherry, and grows in a sterile as well as rich soil. The leaves begin to appear in March and April, and at the end of April have attained their full size, when they are ready for gathering. At the end of August they begin to assume a yellowish rusty color, and soon fill olf. The leaves yield no indigo until the plant is several years old, but the best leaves for making indigo are obtained from low bushy plants. They improve when kept for a day or two, but when they begin to wither, they yield but a small portion of very bad indigo, and when quite dry only a dirty brown fecula. In this they differ from leaves of the common indigo plant, which may be dried before extraction without loss of color. They al?o differ from the latter in not yielding their color to cold water. With cold water only a hard, black, flinty substance is obtained, not blue indigo. It is therefore necessary to employ hot water, which extracts the color very readily. The leaves, having been collected, are on the ensuing day thrown into copper scalding-vessels, which are then filled with cold water to within 2 or 3 inches of the top. Hard water containing a large (piantity of bicarbon- ate of lime is belter adapted for tlip* purpose than rain water. The fire is then lighted and maintained rather briskly until the liquor acquires a deej) green color. The leaves tlicn begin to assume a yellowish color, the heat of the li(iuor being about 150° to 100° 608 INDIGO. Fahr. The fire is then removed and the liquor run off into the beating-vat. Here it is agitated from 5 to 20 minutes. It is then mixed with about Vvo to Vioo part of lime water, which pi'oduces a speedy granulation. After the indigo has subsided the super- natant liquid appears of a clear Madeira wine color. The ciuantity of indigo obtained amounts to 1 lb. from 250 lbs. of green leaves; but it varies according to the season and the state of the weather. In August and September, the produce is only one-half or two-thirds of what it is in May and June, and even that is diminished if the weather is wet, or the leaves are treated immediately after being gathered. The scalding requires about three hours, and the agitation and precipitation the same time. The indigo is im- proved by treating it with a little sulphuric acid. The only fault it has is, that it breaks into small pieces, unless it has been dried slowly in the shade, protected from tlie sun. In the southern provinces of China a species of Indigofcra is extensively cultivated for the sake of the dye which it affords. In the northern provinces two other plants are employed by the inhabitants for the same purpose. Mr. Fortune, the well-known Chinese traveller, to whom we owe the description of these plants and of the process of manu- facturing indigo from them, states that one of them is grown in the neighborhood of Shangliac, and he has given it the name of hatis imlir/oticd. The other, which is a species oi Jusiicia, is largely cultivated in the hilly country near Ningpo, or rather in the valleys among the hills. It seems to be easily cultivated ; it grows most luxuriantly, and is no doubt very productive. Having evidently been introduced from a more southern latitude, it is not hardy in the province of Chekiang any more than cotton is about Shanghae ; but nevertheless it succeeds admirably as a summer crop. It is planted at the end of April or beginning of May, after the spring frosts are over, and it is cleared from the ground in October. During this period it attains a height of a foot or a foot and a half, be- comes very bushy, and is densely covered with large green leaves. It is cut before any flowers are formed. The plants are grown, not from seed but from cuttings. These cut- tings consist simply of a portion of the stems of the previous year, which, after being stripped of their leaves, arc tied into bundles, each containing upwards of 1,000, and kept during the winter in a dry shed or outhouse, where, after being firmly packed together, they are banked round with dry loam, and covered with straw or litter so as to protect them from the frost. During the winter months the cuttings remain green and plump, and although no leaves are produced a few roots are generally found to be formed or in the act of forming when the winter has passed and the season for planting has come round. In thjs state they are taken to the fields and planted. The w eathcr during the planting season is generally showery, as this happens about the change of the monsoon, when the air is charged with moisture. A few days of this warm showery weather is suffi- cient to establish the new crop, which now goes on growing with luxuriance and requires little attention during the summer, indeed none except keeping the land free from weeds. In the country where this dye is manufactured there are numerous pits or tanks on the edge of the fields. They are usually circular in form, and have a diameter of about 11 feet and a depth of '2 feet. About 400 catties* of stems and leaves are thrown into a tank of this size, which is then filled to the brim with clear water. In five days the plant is partially decomposed, and the water has become yellowish-green in color. At this period the whole of the stems and leaves are removed from the tank with a flat-headed broom made of bamboo twigs. When every particle has been removed, the workmen employed give the water a circular and rapid motion with the brooms just noticed, which is continued for some time. During this part of the operation another man has employed himself in mixing about thirty catties of lime with water, which water has been taken out of the tank for the purpose. This is now thrown into the tank, and the rapid circular motion of the water is kept up for a few minutes longer. When the lime and water have been well mixed in this way the circular motion is allowed to cease. Four men now station themselves round the tank and commence beating the water with bamboo rakes made for this purpose. The beating process is a very gentle one. As it goes on, the water gradually clianges from a greenish hue to a dingy yellow, while the froth becomes of a beautiful bright blue. During the process the head workman takes a pailful of the liquid out of the tank and beats it rapidly with his hand. Under this operation it changes color at once, and its value is judged of by the hue it presents. The beating process gen- erally lasts for about half an hour. At the end of this time the whole of the surface of the li(iuid is covered with a thick coating of froth of the most brilliant colors, in which blue predominates, especially near the edges. At this stage, it being desirable to incorporate the froth with the liquid below it, it is only necessary to throw a small quantity of cab- bage oil on the surface of the froth. The workmen then stir and beat it gently with their flat brooms for a second or two, and the whole instantly disappears. The liquid, which is now darker in color, is allowed to repose for some hours, until the coloring matter has sunk to the lower stratum, when about two-thirds of the liquid is drawn off and thrown away. The remaining third part is then drawn into-a small square tank on a lower level, * A Chinese catty is equal to IJ lbs. INDIGO. 609 which is thatched over with straw, and here it remains for three or four days. By this time the coloring matter has separated itself from the water, which is now entirely drained off, the dye occupying three or four inches of the bottom in the form of a thick paste and of a beautiful blue color. In this state it is packed in baskets and exposed for sale in all the country towns in this part of China. Like the Shanghae indigo, made from Isatis indigotica, it is called '''■ T'ien-cking'''' by the Chinese. — Gardne/s Chronicle and Agricultural Gazette, April 8tli, 1854. The cultivation of indigo in Central America has fallen off very much of late years. Nicaragua formerly exported annually about 5,000 bales of 150 lbs. each. At present the export probably does not exceed 1,000 or 2,000 bales. Under the government of Spain, the state of San Salvador produced from 8,000 to 10,000 bales annually. A piece of ground equal to two acres generally produces from 100 to 120 lbs., at a cost of not far from 30 to 40 dollars. There is an indigenous biennial plant abounding in many parts of Central America, which produces indigo of a very superior quality, but gives less than half the weight which is afforded by the cultivated species. Tlie Indigofera disperma is the species employed in cultivation. It attains its highest perfection in the richest soils. It will grow, how- ever, upon almost any soil, and is very little affected by drought or by superabundant rains. In planting it, the ground is perfectly cleared, usually burnt over, and divided with an implement resembling a hoe into little trenches, 2 or 3 inches in depth, and 12 or 14 apart, at the bottom of which the seeds are strewn by hand, and lightly covered with earth. A bushel of seed answers for 4 or 5 acres of land. In Nicaragua it is usually planted towards the close of the dry season in April or Slay, and attains its per- fection for tile purpose of manufacture in from two and a half to three months. During this time it requires to be carefully weeded, to prevent any mixture of herbs, which would injure the quality of the indigo. When it becomes covered with a kind of green- ish farina, it is in a fit state to be cut. This is done with knives at a little distance above the root, so as to leave some of the branches, called in the AVcst Indies "ratoons," for a second growth, which is also in readiness to be cut in from six to eight weeks after. The crop of the first year is usually small ; that of the second is esteemed the best, although that of the third is hardly inferior. It is said that some fields have been gathered for ten consecutive years without being re-sown, the fallen seed obviating the necessity of new plantings. After the plant is cut, it is bound in little bundles, carried to the vats, and placed in layers in the upper or larger one called the steeper, (mojadora.) This vat holds from 1,000 to 10,000 gallons, according to the requirements of the estate. Boards loaded with weights are then placed upon the plants, and enough water let on to cover the whole, which is now left to steep or ferment. The rapidity of this process depends much upon the state of the weather and the condition of the plant. Sometimes it is accomplished in 6 or 8 hours, but generally requires from 15 to 2i). The proper length of time is deter- mined by the color of the saturated water ; but the great secret is to check the fermen- tation at the proper point, for upon this, in a great degree, depends the quality of the product. Without disturbing the plant, the water is now drawn off by cocks into the lower vat or " beater," (golpeadoro,) where it is strongly and incessantly beaten, in the smaller estates with paddles by hand, in the larger by wheels turned by horse or water power. This is continued until it changes from the green color, which it at first displays, to a blue, and until the coloring matter, or flocculas, shows a disposition to curdle or subside. This is sometimes hastened by the infusion of certain herbs. It is then allowed to settle, and the water is carefully drawn off. The pulp granulates, at which time it resembles a tine soft clay ; after which it is put into bags to drain, and then spread on cloths in the sun to dry. When properly dried, it is carefully selected according to its quality, and packed in hide cases, 150 lbs. each, called serojis. The quality has not less than 9 grada- tions, the best being of the highest figure. From G to 9 are called _/?orfs, and are the best ; from 3 to 6 cor/es : from 1 to 3, inclusive, cobres. The two poorer qualities do not pay expenses. A mansana of 100 yards square produces on an average about one seroon at each cutting. After the plant has passed through the vats, it is required by law that it shall be dried and burnt; because in decomposing it generates by the million an annoy- ing insect called the "indigo fly." The following account of the manufacture of indigo on the Senegal is taken from Perottct's " Art de I'lndigotier : " The land destined to the cultivation of the plant ought to be perfectly level and free from undulations, so as to prevent the seed from being washed into the hollows or lower parts by the heavy rains so frequent in the tropics. Soils of a grayish color abounding in •clay are not adapted for the purpose, as they arc too compact and cold. Sandy soils of a whitish color must also be avoided. Light soils, abounding iu Immus or vegetable remains, and having a color between gray and dark brown, are to be preferred to all others. The soil should, at all events, not be one very retentive of moisture. The Vol. III.— 39 610 INDIGO. quantity of indigo obtained from the came weight ot plant may vary, according to the soil, from 4 lbs. to 10 lbs., and the quality also varies in a corresponding degree. The extent of ground which is required for the production of indigo on a large scale is so great that the use of manure becomes almost impossible. Nevertheless the employment of the refuse of the plant, after the extraction of the indigo, as a manure on fresh plantations, is found to be attended with very beneficial results. The ground, if new, must be turned up by means of a plough or hoe, to the depth of at least 10 or 12 inches, three times Euccessivelv at intervals of 3 months, before the sowing takes place. The sowing must only be undertaken in fine weather, never during heavy rain. The seed employed should be perfectly ripe, and, if possible, not more than one year old. It is to be left in the seed-vessels in which it is contained until the time when it is wanted. The latter are then put into a wooden mortar and reduced to fragments, and the seed is separated by win- nowing from the dust, debris, &c., with w hich it is mixed. The sowing is to be effected broadcast and as evenly as possible. It should take place, if possible, just before the approach of rain, in which case the use of a harrow is not required, as the rain generally has the effect of completely levelling the ground and covering up the seed with soil. The Indigofera tinctoria, and its varieties macrocarpa and emarginata, being a plant with numerous crowded branches, it is not necessary, in sowing it, to take more than from 6 to 7^ kilogrs. of seed to 1 arpent of ground ; but the Indigofera anil, being more spar- ingly branched, and therefore taking up less room, retjuires to be more thickly sown. At about ten or twelve days after sowing, when the young indigoferEe have attained a height of about 81 to lOS' millimetres, the ground must be carefully weeded, and this operation must be repeated as soon as the weeds have again made their appearance and commenced to interfere with the growth of the crop. When the season is favorable, three months are generally sufficient to enable the plants to attain the degree of develop- ment necessary for the production of indigo. At the period when inflorescence com- mences the plant is far richer in coloring matter than at any other. As soon, therefore, as there are any indications of flowering, and when the lower leaves, in the axils of w hich the flowers appear, begin to acquire a yellowish tint, and when pressed in the hands produce a small crackling noise, no time must be lost in cutting down the plant. This is effected by means of good knives or sickles, and as near the ground as possible. The stems, after being cut, are tied together into bundles or sheaves and carried to the manu- factory. Since the coloring principle of the indigoferai is extremely susceptible of change by the action of destructive agencies, it is necessary to use the utmost despatch in gathering the crop, and to have the manufactory of such a size in proportion to the plantation, that no time may be lost in working up the material as soon as gathered. The plants must on no account be cut when they are moistened either with rain or dew, because in this case they acquire a blackish tint in consequence of the friction to which they are exposed in cutting them and taking them to the manufactory, this tint being a sign of the disappearance of the coloring matter. Besides this, it has been observed that during the continuance of rain the indigo-producing principle diminishes very consider- ably, and sometimes even disappears entirely, so that, if cut during or immediately after rain, the plants yield little or no indigo. The indigo plant is subject to the attack of a green caterpillar, which sometimes appears in such quantities as to destioy the w hole crop. No certain and easy means of destroying this pest is known. It has been recommended to pass wooden rollers over the ground, before the plants have attained any great size, so as to crush the caterpillars without injuring the plants, and this plan has been attended with partial success. In order to obtain good results in the manufacture of indigo, it is necessary that the plants should be of the same age, of the same species, and from the same field. The Indigofera anil begins to ferment several hours sooner than the /. finctoria, r-o that if a mixture of both be taken, the produce from either one or the other will be lost, and the indigo obtained will also be of a bad quality. The plants should, as soon as possible after being gathered, be placed in the steeping-vat, which is a vessel built of bricks, and well lined with cement, from 3| to 8 metres in length, of the same width, and about 1 metre deep. In this vessel the plants are arranged in successive layers, the lower layers being slightly inclined towards one end, in order to facilitate the subsequent running off of the hqiior. The vessel being full, a number of poles of fir-wood are laid lengthways over the plants, at a distance of 162 mill, from one another. Three beams are then laid crosswise over the poles, their ends being well secured by passing them through slits which are cut in the upright posts at the sides of the cistern, and then fixing them by means of iron pins, passing through holes in the posts. By this means the plants are prevented from rising above the surface of the liquor during the process of maceration. The vat is now filled with water from an adjacent cistern, in which it has been allowed to stand for 24 hours for the purpose of allowing all foreign matters contained in it to be deposited. After standing in contact with the leaves for about 6 hours, a change usually begins to manifest itself in the liquor, which must therefore, from that time for- INDIGO 611 ward, be carefully watched. As Roon as this liquor begins to acquire a green color, and when a little of it, on being kept for a short time in the moutii, leaves a slight impression of harshness [dprete) on the tongue and the palate, it is a sign that the maceration is com- plete, and that the liquor should be drawn otf without delay. If this be not done, the color of the liquor changes from green to brawn, a new species of fermentation com- mences, accompanied by the formation of acetic acid, and the plant begins to yield sub- stances of a mucilaginous nature, which contaminate the indigo, and completely spoil its quality It is therefore of the greatest importance to ascertain ex;ictly when the macer- ation of the plant is complete. The following are the chief indications of this ])oint having been attained: 1. When the water, which was at first clear, begins to become muddy and acquire a slight greenish tinge. 2. When bubbles of a greenish color rise to the surface here and there. 3. When towards the edge of the vat some mucilage, or a kind of grayish scum, commences to be iormcd. 4. When a very slight purple pellicle is observed on the surface of the liquor, especially near the corners of tlie vat. 5. Wlien the liquor begins lo exhale a slight but not disagreeable odor of herbs. When the fer- mentation has proceeded too far, the following phenomena present themselves: 1. A considerable quaniity of large bubbles of air are disengaged, which burst at the surface, forming a layer of grayish mucilage. 2. The surface of the liquor becomes covered with a copper-colored pellicle. 3. A heaving of the liquor in the vat is observed, giving rise to the disengagement of large greenish bubbles which communicate a brownish color to the water. 4. The liquor acquires a fetid smell, a strongly acid taste, and a soapy appearance. These phenomena manifest themselves when the weather is hot, after the fermentation has continued about 12 or 14 hours. It then becomes impossible to obtain indigo of good quality, the only product being a black matter resembling wax. The liquor is now run off from the steeping-vat into the beater, which is a cistern of about the same dimensions as the former, but situated at a rather lower level. Here it is subjected to the beating process, the object of which is to expose the reduced indigo to the oxygen of the atmosphere, as well as to promote the disengagement of the carbonic acid gas with which the liquid is charged, and which prevents the precipitation of the indigo. The beating is performed by men, who, provided with paddles, agitate the liquid rapidly, so as to bring every part of it successively into contact with the air. It is of importance that this process should be broken off at the right moment, for if it be continued too long, the grain formed at first will redissolve and be lost. And if, on the other hand, it be arrested before the proper time has arrived, a portion of the indigo will remain unpre- cipitafed. In order to ascertain in what state the liquor is, a little of it nmst be poured into a drinking-glass and mixed with an equal volume of clear water. If there is formed round the circumference of the glass a line of a bluish-green color, the beating must be continued ; but if, on the contrary, the liquid appears of a uniform browMi color, and if ou adding to it a few drops of clear lime water with the finger the indigo precipitates immediately in grains, the process must be arrested. The beating usually occupies from an hour and a half to two hours. The liquid is now to be well mixed with about '/lo of its volume of clear lime water, and allowed to rest until the indigo has quite settled. By opening successively the plugs which are placed at different heights in the side of the vessel, the clear liquor is then drawn off in separate portions and permitted to run away, care being taken that none of the indigo is allowed to be carried away with the water. By means of an opening situated near the bottom of the beating-vat the indigo mixed with water is then run off, and, flowing through a canal, is received on a cloth strainer or filter. This filter rests on a round or four-cornered vessel, the top of which is on a level with the surface of the ground, and which is called the diablotin. When the liquor has run through the filter, the indigo which remains behind in a state of paste is mixed up again with water, and the mixture is poured on a canvas filter and allowed to run immediately into the boiler. The refuse matter, consisting of leaves of the plant, &c., remains on the canvas, while the indigo suspended in water runs through. Tlie boiler is a vessel with sides of masonry and a bottom consisiing of a copper plate which rests on iron bars, and is well cemented to the sides. Underneath the copper plate is the-fire-place. The top must be covered with a wooden lid, consisting of two flaps which are fixed to hinges at the sides, and meet together over the top. At the moment when the mixture of indigo and water is introduced into the boiler, the latter must already be about one-third full of hot water, the mixture lieing sufficient almost to fill it entirely. The heat is now raised gradually to the boiling point, and the boiling is continued lor about two hours. In order to prevent the indigo from adhering to the bottom and sides of the boiler, the liquor must be kept continually slirred with a wooden riike. Tlic ob- ject of the boiling is to drive away all tiic carbonic acid that mny still be present in the liipior, to remove the soluble extractive matters which would render the indigo dull and impure, to prevent the fermentation or putrefaction of the indigo which would otherwise take place, and, lastly, to facilitate the subsequent processes of filtering and pressing. The fire having been removed, the liquor is allowed to stand for some time, and as soon 612 INDIGO. as the indigo has settled the supernatant liquid is drawn off by means of taps fixed in one of the sides of the boiler. The lowest tap is then opened, and the indigo is run off with the water and received on a filter, consisting of blue Guinea cloth stretched on a frame. The first portions of hquid which run through are usually colored with indigo, and must therefore be caught in a suitable vessel and poured on the filter again. As soon as the liquid has percolated, the indigo, which is new a compact paste, is removed from the filter by means of a wooden ladle and put into a press, which consists of a wooden box pierced with holes. The press having been lined with cloth, the indigo is put in, the cloth is folded round it as evenly as possible, a wooden Hd is dropped on the cloth, and the mass is submitted to pressure by means of a screw, until no more liquid runs through at the bottom, which takes place as soon as the indigo lias been reduced to about a third of its original volume. The press is then opened, the indigo is taken out of the cloth, laid on a table, and divided )>y means of a knife into pieces of a cubical shape. These cubes are then taken to the drying-shed, where they are placed on trellises covered with matting or very thin cloth, so as to adniitof the free passage of air. Care must be taken not to dry them too rapidly, otherwise the cakes would crack and split into fragments, which are then of little commercial value, and it is therefore necessary to protect them from currents of dry air by covering them with canvas or Guinea cloth. During the drying process, which occupies from 8 to 10 days, the cakes should be tuined several times. They are then closely packed in boxes, each box holding about 25 kilo- giammes. The boxes shotdd be lined with paper. It may be remarked, that when the indigo is of good quality, the volume of the paste diminishes very little when subjected to pressure. If the process of filtering takes up much time and the pressing is attended with difficulty, it may be anticipated that the indigo will turn out of bad quality. This may proceed from the plant having been overgrown, or from the maceration or the beating process having been continued too long, or from the employ- ment of too large a quantity of lime water. The difficulty experienced in pressing the indigo paste, and which is often so great as to cause the cloth in which it is enveloped to break, is caused by the presence of a mucilaginous or viscous substance mixed with the indigo, which may be removed by treating the paste again with boiling water, and repeating the operations of filtering and pressing. In reo'ard to the state in which indigo exists in the plants from which it is derived, and the nature of the process by which it is obtained, various opinions have been entertained by chemists. Berthollet, in his work on dyeing, says, " that the three parts of the process employed have each a different object. In the first a fermentation is excited, in which the action of the atmospheric air does not intervene, since an inflammable gas is evolved. There probably results from it some change in the composition of the coloring particles themselves ; but especially the separation or destruction of a yellowish substance, which gave to the indigo a greenish tint, and rendered it susceptible of undergoing the chemical action of other substances. This species of fermentation passes into a destructive putrefac- tion, because the indigo has a composition analogous to that of animal substances. Hitherto the coloring particles have preserved their liquidity. In the second operation, the action of the air is brought into play, which, by com))ining with the coloring particles, deprives them of their solubility, and gives them the blue color. The beating serves, at the same time, to dissipate the carbonic acid which is formed in the first operation, and which by its action presents an obstacle to the combination of the oxygen. The separation of this acid is promoted by the addition of lime ; but if an excess be introduced, it counteracts the free combination of the oxygen. The third part of the process has for its objects, the deposition of the coloi-ing matter, become insoluble by combination with oxygen, its separation from foreign substances, and its desiccation, which gives it more or less hardness, whence its ap- pearance varies." De Cossigiiy was of opinion that volatile alkali was the agent by which the coloring matter was extracted from the plant and held in solution until volatilized by the agitation process. Roxburgh concluded from his experiments, " that the indigo plants contain only the base of the color, which is naturally green ; that much carbonic acid is disengaged during its extraction from the leaves; that the carbonic acid is the agent whereby it is probably extracted and kept dissolved ; that ammonia is not formed during the process ; that the use of the alkalies employed is to destroy the attraction between the base and the carbonic acid ; and that the vegetable base, being thereby set at liberty, com- bines with some coloring principle from the atmosphere, forming therewith a colored insolu- ble fecula, which falls to the bottom and constitutes indigo." Chevreul, who was the first chemist of any eminence to examine the indigo-bearing plants and their constituents, inferred from his analyses of the Ixafin tindoria and the Indigofcra anil, that these plants contain indigo in the white or reduced state, in the same state in which it exists in the indigo vat ; that in this state it is held in solution by the vege- table juices, and that when the solution is removed from the plant it is converted by the action of the atmospheric oxygen into indigo-blue. Giobert, from an examination of the hatis tinctorin, drew the following conclusions: 1. Indigo-blue does not preexist in the INDIGO. 613 plant, but is formed during the operations by means of which we believe it to be extracted. 2. There exists in a small number of plants a peculiar principle, different from all the known proximate constituents of plants, and which has the property of being convertible into indigo ; this principle may be called indigoc/ene. 3. This principle differs from indigo in containing an excess of carbon, of which it loses a portion, in passing into the state of indigo-blue, by the action of a small quantity of oxygen which it takes up. 4. The loss of this portion of carbon must be attributed to its undergoing combustion and being converted into carbonic acid. 5. It differs in its properties from common indigo in being colorless and soluble in water, and by its greater combustibility, which causes it to undergo sponta- neous combustion at the ordinary temperature of the atmo.sphere. 6. Its combustibility is enhanced by heat and by combination with alkalies, especially lime ; it is diminished by the action of all acids, even carbonic acid. About the year 1839, the Pylogonum tinctorium, an indigo-bearing plant indigenous to China, became the subject of a series of investigations by several French chemists, chiefly with a view to ascertain whether this plant, if grown in France, could be advantageously employed in the preparation of a dyeing material as a sub- stitute for foreign indigo. Baudrimont and Pelletier, after an examination of this plant, arrived at the conclusion that the indigo is contained in it as reduced indigo, in the same state as it is in woad, according to Chevreul. Robiquet, Colin, Turpin, and Joly, on the other hand, expressed a very decided conviction that indigo-blue preexists in the plant, but not in a free state ; that it is combined witli some organic .substance or substances which ren- der it soluble in water, ether, and alcohol ; and that the operation of potent agencies is requi- site in order to destroy this combination and set the indigo at liberty. The explanation of Chevreul, proceeding from an authority of such eminence, and being the simplest, has been adopted by most chemists. Nevertheless there are objections to it which render it inad- missible. Reduced indigo is a body which is only soluble in alkalies, and cannot, there- fore, be contained as such in the juice of indigo plants, which is mostly acid. As it also takes up oxygen with the greatest avidity, and is converted into indigo-blue, it is difficult to conceive how the whole of it can be preserved in a colorless state in the cells of plants, in which it must occasionally come in contact with the oxygen eliminated by the vegetable organism. If these plants contained reduced indigo, the juice ought, moreover, to turn Ijlue the moment it became exposed to the atmosphere, which is not always the case. The necessity for a long process of fermentation in order to obtain the coloring matter would also not be very apparent, the mere contact with oxygen being, it might be supposed, all that was necessary for the purpose. The facility with which the indigo-blue is destroyed if the process of fermentation is carried too far, is also inconsistent with the supposition that it is contained in plants, eitha- as such or in a deoxidized state, since indigo-blue is a body not easily decomposed, except iiy very powerful agents. In order to throw some light on this subject, an investigation was undertaken by Schunck into the state in whicli indigo-blue exists in the Isatis tinctoria, or common woad, which is the only plant indigenous to Europe that yields any considerable quantity of the coloring matter. Schunck succeeded in obtaining from that plant a substance of very pe- culiar properties, to which he gave the name of Indican. This substance has the appear- ance of a yellow or light brown transparent syrup. It has a bitter taste. It is very easily soluble in water, alcohol, and ether ; its solutions are 3'ellow, and have an acid reaction. Its compounds with bases are yellow. When its watery solution is mixed with a strong acid, such as muriatic or sulphuric acid, no change takes place at first, but on leaving the solution to stand, or on heating it, it becomes blue and opalescent, then acquires a purple color, and at length deposits a quantity of purplish-blue flocks, which are quite insoluble in water. These flocks consist for the most part of indigo-blue, but they contain also a red coloring matter and several brown substances of a resinous nature. The supernatant liquid contains a peculiar kind of sugar, and on Ijeing distilled yields carbonic, formic, and acetic acids. Hence it follows that the plant does not contain indigo-blue ready formed, either in the blue or colorless state — that the latter exists in the vegetable juice in a state of combi- nation with sugar, forming a compound of that peculiar class known to chemists as gluco- sides. This compound is readily dissolved by water, and the indigo-blue may then be lib- erated and precipitated from the solution by means of acids, and probably also by other agents, but the simultaneous action of oxygen is not necessary during the process of decom- position which the compound undergoes in yielding indigo-blue. Now if, as seems proba- ble, the various species of indigofei-a contain indican or some similar substance, the phe- nomena which take place during the process of manufacturing indigo may easily be explained. During the steeping process the indican is dissolved, and in consequence of the fermentation which then takes place in the liquor it is decomposed into indigo-blue and sugar. The former would then be precipitated, but since ammonia is, according to most ■ authors, evolved at the same time, tiie indigo-blue is, by the simultaneous action of the alkali and the sugar, or other organic matters contained in the li((uid, reduced and dis- solved, forming a true indigo vat, from which the coloring matter is afterwards precipitated by the combined action of the atmospheric oxygen and the lime, during the beating juo- 614 INDIGO. cess. According to Schunck, two distinct periods may be observed in the decomposition of indican. During the first period, indigo-blue is the chief product of decomposition ; during the second, the red and brown resinous matters make their appearance with very little indigo-blue. The formation of carbonic, acetic, and formic acids is, according to Schunck, dependent on that of the brown resinous matters. It would appear, therelbre, that the copious disengagement of carbonic acid, as well as the acid taste, attributed to acetic acid, sometimes observed during the manufacture of indigo, are phenomena which indicate the formation, not of indigo-blue, but of other substances, which may prove very injurious to the quality of the indigo. These substances, being soluble in Jilkalies, but insoluble in water, are precipitated, as soon as the liquid loses the alkaline reaction which it possesses at the commencement, and becomes acid. Though indigo-blue is a body of very stable character, not easily decomposed when once formed, except by potent agencies, still the assertion of Perottct and others, that " nothing is more fugitive and more liable to be acted on by destructive agencies than the coloring principle of the indigofer?e," will be easily understood when the following facts, mentioned by Schunck, are taken into consideration : If a watery solution of indican, this indigo-producing body, be boiled for some time, it then yields by decomposition, not a trace of indigo-blue, but only indigo-red, and if it be boiled with the addition of alkalies, it then gives neither indigo-blue nor indigo-red, but only the brown resinous matters before mentioned. The mere action of alkalies is therefore suffi- cient to cause the molecules, which would otherwise have gone to form indigo-blue, to arrange themselves in a totally different manner and yield products which bear very little resemblance to it. It is evident, therefore, that one of the chief oljects to be kept in view by the manufacturer of indigo, is the proper regulation of the process of fermentation, so as to prevent the formation of the other products, which take the place of indigo-blue, and are formed at its expen.se. The indigo of commerce occurs in pieces, which are sometimes cubical, sometimes of an irregular form. These pieces are firm and dry, and are easily broken, the fracture being dull and earthy. It is sometimes lighter, sometimes apparently heavier than water, this difference depending on its being more or less free from foreign impurities, as well as upon the treatment of its paste in the boiling, pressing, and drying operations. Its color is blue of different shades, as light blue, purplish blue, coppery blue, and blackish blue. On being rubbed with the nail, or a smooth hard body, it assumes the lustre and hue of copper. It is usually a homogeneous mass, but it occasionally contains grains of sand or other foreign bodies, and sometimes presents inequalities of color. It is frequently full of small cavities, which proceeds from the drying process having been conducted too rapidly, and it is also covered at times with a whitish matter consisting of mould. It varies very much in con- sistency, being sometimes diy, hard, and compact, whilst sometimes it is easily broken into thin flat pieces. Indigo is devoid of smell and taste. When applied to the tongue, how- ever, it adheres slightly, in consequence of the property which it possesses of lapidly ab- sorbing moisture — a property which is often had recourse to in order to ascertain its quality. When thrown on red-hot coals it yields vapors of a deep purple color, which, when con- densed on cold bodies, give shining needles having a coppeiy lustre. It is insoluble in water, cold alcohol, ether, muriatic acid, dilute sulphuric acid, cold ethereal and fat oils; but boiling alcohol and oils dissolve a little of it, which they deposit on cooling. Creosote has the property of dissolving indigo. Indigo varies very much in quality, but it requires much discrimination in order to judge faiily of the quality of any sample from mere inspection and afiplication of the tests usually employed by dealers. A cake of indigo being broken, and the nail or the edge of a .shilling being passed with a tolerable degree of pressure over the fractured part, a fine coppery streak will be produced if the indigo is good. If the indigo furrows up on each side of the nail it is weak and bad, and if the coppery streak be not very bright it is not considered good. When a jiiece of indigo is broken the fracture should be held up to the sun, and if it h;)s not ))een well strained from the dros.s, particles of sand will be seen glis- tening in the sun-light. The outside or coat should also lie as free from sand as possible. When the squares are broken in the chests the indigo fetches a low price, and if it is very much crushed it is only bought by the consumers for immediate use. The methods em- ployed for ascertaining the true amount of coloring matter in any sam.ple of indigo will be described below. Indigo is generally classified according to the various countries from which it is obtained. The principal kinds are the ibllowing: Bengal, Oude, Madras, Manilla, Java, Egyptian, Guatemala, Caracc;i,s, and Mexican. At the present diiy the finest qualities of indigo are obtained from Bengal, the produce of that country having now taken the place in public estimation which was once occupied by that of the Spanish colonies. The export of indigo from Bengal, which in 1853 amounted to 120,000 maunds, (of V-l l))s. 10 oz.,) would require for its culture about 1,025,000 acres, and an annual expenditure of £1,300,000. Of this extent of land about 550,000 acres are believed to be included in the Lower Provinces, and consist chiefly of INDIGO. 615 alluvial land »escued from the rivers. The best qualities of Bengal indigo are manufac- tured in the Jessore and Kishenaghaur districts, but each district produces a quality pecu- liar to itself, and differences of a less striking character may be perceived in the produce of different factories. The Bengal indigo, when packed in chests, consists of four principal qualities, viz., the blue, purple, violet, and copper. But these kinds, by passing over into one another, produce a number of intermediate varieties, such as purply blue, blue and violet, purply violet, &c. The various qualities would, therefore, be distinguished as follows: 1. Blue. 2. Blue and violet. 3. Purple. 4. Purple and violet. 5. Violet. 6. Violet and copper. 7. Copper. The leading London brokers, however, classify Ben- gal indigo into the following grades : fine blue, fine purple and violet, tine red and violet, good purple and violet, middling violet, middling defective, consuming fine, middling and good, ordinary, ordinary and lean trash. The finest qualities of Bengal indigo present the following characteristics : They consist of cubical pieces, are light, brittle, of a clean frac- ture, soft to the touch, of a fine bright blue color, porous, and adhering to the tongue. The lower qualities have a duller color, assume more and more of a reddish tinge, are heavier, more compact, and less easily broken. The indigo from the upper provinces of India comes chiefly from Tyroot, Oude, and Benares. It is inferior to Bengal indigo. Of Madras indigo there are two kinds, viz. : 1. Dry leaf, made from dry stacked leaves; and, 2. Kurpah, which is manufactured from the wet leaf in the same way as Bengal indigo. The latter has only come into use since 1830. Both are of inferior quality to Bengal indigo. The Manilla indigoes present the marks of the rushes upon which they have been dried. The pieces are either cubical, or flat and square, or of irregular shape. The quality is very unequal. Java indigo occurs in flat, square, or lozenge-shaped masses, the quality ap- proaching that of Bengal. Both these kinds are consumed chiefly on the continent of Europe. Guatemala indigo is imported into this country in serons or hide wrappers, each con- taining about 150 lbs. net. It occurs in small irregular pieces, which are more or less brittle, compact, lighter than water, and of a bright blue color, with an occasional tinge of violet. There are three kinds of Guatemala indigo, viz. : 1. Flores, which is the best, and approaches in quality that of the finer Bengal indigoes ; 2. Sobres ; and, 3. Cortes, which is the lowest in quality, being heavy, difficult to break, and of a coppery-red color. Of the first kind very little now reaches the market. The indigo of Caraccas is, generally speak- ing, inferior to that of Guatemala. The manufacture of indigo was formerly carried on in St. Domingo, but has for some time been entirely abandoned. The indigo of commerce, even when not adulterated, is a mixture of different matters. When it is heated in a state of fine powder to 212° F. it loses from 5 to 10 per cent, in weight, the loss consisting of water. When the dry powder is heated in a crucible a great part of it burns away, and there is left at last a grayish ash, consisting of the carbonates and phosphates of lime and magnesia, sulphate of lime, alumina, oxide of iron, clay, and sand. Tliese matters are partly derived from the plant, partly from the lime and the im- purities of the water employed in the manufacture. The quantity of inorganic matter con- tained in ordinary indigo varies very much. In the better qualities it amounts on an average to aljout 10 per cent, of the weight; whilst in the inferior qualities, especially of Madras indigo, it often rises to between 30 and 40 per cent. The organic portion of the indigo, or that which is dissipated when indigo is heated, also consists of several different substances. By treating indigo with various solvents, Berzclius obtained, besides indigo-blue, the true coloring matter of indigo, three other bodies, viz., indiffo-c/lnten, indiffo-brown, and indiffo-red, which seem to be contained in various proportions in all kinds of indigo. Indi- go-gluten is obtained by treating indigo with dilute sulphuric, muriatic, or acetic acid, and then with boiling water. It is left, on evaporation of its solutions, as a yellow transparent extract, which is soluble in spirits of wine, and easily soluble in water, more difficultly in acid liquids. Its taste is like that of extract of meat. It )'ields by dry distillation much ammonia and a fetid oil, and behaves in most respects like vegetable gluten. On treating the indigo, after being freed from the indigo-gluten, with hot strong caustic lye, the indigo-brown, together with a little indigo-blue, dissolves, forming a dark brown, almost black solution, from which the indigo-brown, after filtration from the portion insoluble in alkali, is precip- itated by means of acid. After being purified, indigo-brown has the appearance of a dark ))rown transparent resin, which is almost tasteless and quite neutral. By dry distillation it affords ammonia and cmpyreumatic oil. It is decomposed by nitric acid and chlorine. It combines both with acids and bases. Its compounds with alkalies are dark brown, and easily soluble in water. The compound with baryta is not easily soluble in water, and that with lime is insoluble. By boiling the alkaline compounds with lime in excess, the indigo- brown may be separated and rendered insoluble. The green substance obtained by 616 INDIGO. Chevreul from indigo seems to have been a compound of indigo-bro^vn with ammonia containing a little indigo-blue, either in a state of combination or mechanically intermin- gled. Indigo-brown seems to bear a great resemblance, in many of its properties, to the brown resinous substances obtained by Schunck in the decomposition of indican with acids. From its constant occurrence in all kinds of indigo, it may be inferred that it is not a mere accidental impurity, but stands in some unknown relation to indigo-blue. As long, how- ever, as its origin and composition are unknown, this must remain a mere supposition. After the removal of the indigo-gluten and indigo-brown, the indigo is exhausted with boil- ing alcohol of specific gravity 0-83. A dark red solution is obtained, which is filtered and distilled, when the indigo-red contained in it is deposited as a blackish-brown powder, which is quite insoluble both in water and in alkaline liquids. Indigo-red, according to Berzelius, is amorphous, but by distillation in vacuo jields a white crystalline sublimate, as well as unchanged indigo-red. Concentrated sulphuric acid dissolves it, forming a dark yellow solution, which deposits nothing on being mixed with water ; the diluted solution is rendered colorless by avooI, which at the same time acquires a dirty yellowish-brown or red color. The description given by Berzelius leaves it doubtful whether the indigo-red ob- tained by him from indigo was a pure, unmixed substance. From the leaves of the iiidigo- feras, as well as from those of the Isaiis tinctoria, a substance may, according to Schunck, be extracted, which has received from him the name of indirxibiiie, but which seems to be merely indigo-red in a state of purity. This substance has, according to Schunck, the fol- lowing j)roperties: it crystallizes in small silky needles of a lirownish-purple color, which, when rubbed with a hard liody, show a slight bronze-like lustre. When carefully heated it may be entirely volatilized, yielding a yellowish-red vapor, which condenses in the form of long plum-colored needles, having a slight metallic lustre. It dissolves in concentrated sulphuric acid, forming a sohition of a beautiful purple color, which when diluted with water yields no deposit and then imparts a fine purple color to cotton, wool, and silk. It is in- soluble in water, but dissolves in boiling alcohol with a splendid purple color. It is insolu- ble in alkalies, but dissolves when exposed to the combined action of alkalies and reducing agents, just as indigo-blue does, forming a solution from which it is again precipitated on exposure to the oxygen of the atmosphere. This solution dyes cotton purple. In most of its properties this body bears a striking resemblance to indigo-blue, and the composition of the two is identical. It has been doubted whether these various substances or impurities with which indigo- blue is associated produce any effect in the dyeing process on cotton. In a memoir by Schwarzenberg, to which a prize was awarded by the Societe Industrielle de Mulhouse, the author arrives at the conclusion that neither indigo-gluten, indigo-brown, nor indigo-red gives rise to any appreciable effect when added to an indigo vat prepared with pure indigo- blue. Nevertheless differences are observable hi dyeing with different kinds of indigo, which can only be explained on the supposition that something besides indigo-blue takes part in the process. In the ordinary blue vat, made with copperas and lime, any effect which might be produced in dyeing by the indigo-brown is neutralized by the lime, which forms with it an insoluble compound. Indigo-red, however, dissolves, as mentioned above, in contact with alkalies and reducing agents, and the solution imparts a purple color to cotton. In the ordinary indigo vat its presence may be detected by precipitating a portion of the liquor, and treating the precipitate with boiling alcohol, which then usually acquires a red color. It is possible, therefore, that a small part of the effect produced in dyeing with indigo may be due to indigo-red. That portion of the indigo which remains after treatment with acid, alkali, and alcohol, consists essentially of indigo-blue, the true coloring matter of indigo, mixed, however, with sand, earthy particles, and other impurities. In order to purify it, the residue, while still moist, is to be mixed with lime, the quantity of which must amount to twice the weight of the crude indigo, and which has been previously slaked with water. The mixture is then put into a bottle capable of holding about 150 times its volume of water, and the bottle is filled up with boiling water and shaken. A quantity of finely powdered proto- sulphate of iron, amounting to f of the weight of the lime is then added, the bottle is closed with a stopper, well shaken, and left to stand for several hours in a warm place. The mass gradually becomes green, and the indigo-blue is then converted by the pre- cipitated protoxide of iron into reduced indigo, which dissolves in the excess of lime, form- ing a deep yellow solution. This solution when clear is poured off" from the deposit into a vessel containing a sufficient quantity of dilute muriatic acid to supersaturate the whole of the lime. The reduced indigo, which is precipitated in grayi.'^h-white flocks, is agitated with water until it has become blue, and the regenerated indigo-blue is collected on a filter and washed with water, in order to remove the chloride of calcium and excess of muriatic acid. The following method of obtaining pure indigo-blue has been recommended by Fritzsche : 4 oz. of crude indigo and the same weight of grape sugar are put into a bottle capable of holding 12 lbs. of water; a solution of (J oz. of concentrated caustic soda lye in alcohol is then added, after which the bottle is filled with hot spirits of wine of 75 per INDIGO. 617 cent., and the whole is left to itself for some time. The liquid becomes at first wine-red, then yellow, and on being filtered and left exposed to the air, deposits the indigo-blue in small crystalline scales, which are to be filtered olF and washed at first with alcohol, and then with water. Pure indigo-blue has the following properties : Its color is dark blue inclining to purple. When rubbed with a hard body it assumes a bright coppery lustre. It has neither taste nor smell, possesses neither acid nor basic properties, and belongs, as regards its chemical alBnities, to the class of indifferent substances. Its specific gmvity is l"oO. When heated in the open air it melts, boils, and burns with a smoky flame, leaving a carbonaceous residue. But when it is heated in a vessel partially closed, or in vacuo, it begins to evolve at a tem- perature of about 550° F. a violet-colored vapor, which condenses on the colder parts of the apparatus in the form of long crystalline needles, which are blue by transmitted light, but exlii jit by reflected light a beautiful coppery lustre. These needles are unchanged indigo-blue. A great portion of the indigo-blue i.s, however, decomposed during the heating process. Indigo-blue is insoluble in water, alkalies, and dilute acids. Boiling alcohol and ' boiling oil of turpentine dissolve a minute quantity of it, and deposit it again on cooling. Fixed oils also dissolve a little of it at a heat exceeding that of boiling water, yielding blue solutions, the color of which, when the heat is further increased, changes, according to Mr. Crum, first to crimson and then to orange. By the action of dilute nitric and chromic acids indigo-blue is decomposed and converted into isati?ie, a body soluble in water and crystallizing in red needles. Cldorine also decomposes indigo-blue, changing it into chlori- sit-ine, a substance having properties very similar to those of isatine. Both isatinc and chlorisatine afford with different reagents a great number of products of decomposition, none of which have, however, as yet found any application in the arts. By the long con- tinued action of boiling nitric acid indigo-blue is converted, first into indicfotic acid, a v^iite crystalline acid, and then into nitropicric acid, which is yellow and crystallized. The latter is sometimes employed for imparting a yellow color to silk and wool, but it is generally prepared from cheaper materials than indigo-blue. The action of concentrated sulphuric acid on indigo-blue is very remarkable. When the acid is poured on the pure substance and gently heated it acquires in the first instance a green color, which changes after some time to blue. No gas of any kind is evolved. When, however, crude indigo is employed, there is a perceptible disengagement of sulphurous acid, resulting from the action of the sulphuric acid on the impurities of the indigo, such as the indigo-gluten, kc. On adding water, a solution of a beautiful deep blue color is obtained. The filtered liquid contains a peculiar acid, to which the names of indigo-sulphuric, snlpjhindigotic, sulphindylic, or ccendeo-sulphiiric acid have been applied. This acid is a so-called double acid. It contains indigo-blue and sulphuric acid, but in such a peculiar state of combination that neither of the two constituents can be detected by ordinary reagents, nor again eliminated as such from the compound. It combines with bases, without either of the two constituents separating. The compounds are called indigo- sulphatex, and are, like the acid, of a dark blue color. When the solution of indigo-blue in concentrated sulphuric acid is diluted with water, there is usually formed a small quan- tity of a dark blue flocculent precipitate, which is the phcnicine of Mr. Crum, or the indir/o- purple of Barzelius. It is a compound of indigo-blue with sulphuric acid, containing less of the latter than indigo-sulphuric acid. It is always formed when the quantity of sulphuric acid employed is not more than eight times that of the indigo-blue, or when the action of the acid on the latter has continued for only a short time. By heating it with an excess of acid it is changed into indigo-sulphuric acid. Though soluble in concentrated sulphuric acid, it is insoluble in the dilute acid, and hence is precipitated on the addition of water. On filtering and washing, however, it begins to dis%olve as soon as the free sulphuric acid has been removed, and may then be completely dissolved by pure water. The solution has a blue color, just like that of indigo-sulphuric acid. Its compounds with bases have a blue color with a purplish tinge. The blue acid liquid filtered from the indigo-purple, on being suj)ersaturated with carbonate of potash or soda, deposits a dark blue powder, which con- sists of the indigo-sulphate of potash or soda. These compounds are iusolulde in water containing a large (luantity of neutral salts, and are therefore precipitated when the excess of sulphuric acid is neutralized by carbonate of potash or soda. As soon, however, as the sulphate of potash or soda has been removed by washing, the indigo-sulphate may be dis- solved m pure water, yielding a dark blue solution. The indigo-sulphates of the alkalies may also be prepared by steeping wool, i)reviously well cleaned, into the solution in sul- phuric acid. The wool takes up the color, becoming of a dark blue color, and after having been well washed with (vater, in order to remove the excess of acid as well as the impurities which are always present in the solution when crude indigo has been employed, is treated with carbonate of potash, soda, or ammonia, which separate the acid from the wool, and produce blue solutions conUiining the salts of the rcs])ective bases. The indigo-sulpliates of t'ne earths and metallic oxides, which are mostly insoluble blue powders, may be obtained from the alkaline salts by double decomposition. By an excess of caustic alkali, indigo- 618 INDIGO. sulphuric acid is immediately decomposed, giving a yellow solution, from wliich it is im- possible to obtain the acid agaiij. By means of reducing agents, such as sulphuretted hydro- gen, nascent hj'drogen, protosalts of tin and iron, &c., indigo-sulphuric acid is decolorized, but the color is restored by the oxygen of the atmosphere. Indigo-sulphuric acid, iu a free state or in combination with alkalies, is employed in the arts for the purpose of imparting a blue color to silk and wool. It has very little affinity for cotton fibre, but is nevertheless employed occasionally for blueing white cotton-yarn and other bleached goods. By treatment with strong boiling caustic potash or soda lye, indigo-blue is gradually de- composed and converted into a colorless crystallized acid, anthranilic acid. By weak solu- tions of cau.stic alkalies, it is not in the least affected. If, however, it be subjected to the combined action of an alkali or alkaline earth and some body having a strong affinity for oxygen, such as protoxide of iron or tin, sulphur, sulphurous or phosphorous aciil, or organic matters, such as grape-sugar, &c., it disappears by degrees, yielding a yellow solution, containing in the place of indigo-blue another substance, which has been called iiidigo-uhite, indigogene, or reduced indiyo. When an excess of some acid is added to the yellow solu- tion, the indigo-white is precipitated in white or grayish-white flocks, which on filtration and exposure to the atmosphere rapidly become blue, and are reconverted into indigo-blue. Indigo-white is insoluble in water, but slightly soluble in alcohol. It is soluble in caustic alkalies, lime, and baryta water. The solutions, on exposure to oxygen, become covered with a pellicle of regenerated indigo-blue. With an excess of lime it gives an insoluble com- pound. Its compounds with alumina and metallic oxides, which are insoluble in water, may be obtained by double decomposition. Salts of oxide of copper, when added to its solu- tions in alkali, convert it immediately into indigo-blue, the oxide of copper being reduced to suboxide. Indigo-blue is also converted into indigo-white when it is exposed to the action of fermenting or putrefying substances, in the presence of water. Here the decomposing organic matter is the reducing agent, and ammonia, which is usually formed during the process of putrefaction, is the solvent of the indigo-white. If a piece of cotton, wool, or silk be dipped into an alkaline solution of indigo-white and then exposed to the atmos- phere, it acquires a blue color, which may be made deeper by repeated dippings and sub- sequent exposure. It is on this property of indigo-white that the dyeing with indigo depends. The true chemical formula of indigo-blue, which was first discovered by Mr. Crum, is CH'NO", and 100 parts contain therefore by calculation '73"28 carbon, 3'81 hydrogen, 10'68 nitrogen, and 12-23 oxygen. The formula of indigo-white is C^IFNO", and it differs therefore from indigo-blue by containing 1 atom more of hydrogen, which is taken up during the so-called reduction of the latter, and lost again by oxidation during its reconver- sion into indigo-blue. Since the value of indigo depends entirely on the quantity of indigo-blue which it con- tains, it is of great importance to ascertain the exact amount of the latter in any given sample of the article. Before commencing the determination of the indigo-blue, a weighed portion of the indigo ought to be heated for some hours at 212° F., and then weighed again. The loss in weight which takes place represents the amount of water contained in the sample. A weighed quantity of the dried indigo is then to be heated over the flame of a lamp until all the organic matter has been burnt away. By weighing the residue which is left the amount of ash or inorganic matter is ascertained. In order, in the next place, to determine the amount of indigo-blue, several methods have been devised by various chemists, none of which, however, yield very accurate results. Of these methods the following are the princii)al ones : — 1. A weighed quantity of finely pounded indigo is ruljbed with water in a porcelain mortar. An equal weight of pure lime is then slaked with water, and the hydrate is well mixed with the indigo. The mixture is then poured into a stoppered bottle of known cajjacity, and the mortar is well rinsed with water, which is added to the rest. The bottle is now heated in a water-bath for several hours, and a ([uantity of finely pounded sulphate of iron is added ; the bottle is then filled up with water, the .stopper is inserted, and after the contents have been well shaken the whole is allowed to repose for some hours, until the indigo has been reduced and the sediment has sunk to the bottom. A portion of the clear liquor is then drawn off with a siphon, and the (piantity of li(iuid having been accurately measured, it is mixed with an excess of muriatic acid, and tlie precipitate, after having been oxidized, is collected on a weighed filter and well washed with water. Lastly, the filter with the indigo-blue is dried at 212' F. and weighed, and the weight of the filter hav- ing been subtracted from that of the whole, the weight of the indigo-blue is ascertained. Supposing now that the whole quantity of liquid had been 200 measures, that 50 measures had been drawn off yielding 10 grains of indigo-blue, then the sample contained on the whole 40 grains of the latter. For 60 grains of indigo it is necessary to take from 1 lb. to 2 lbs. of water. According to Mr. John Dale, of Manchester, who has had great experience in the valua- tion of indigo for practical purposes, tlris method, though rather long and tedious, still INDIGO. 019 gives more accurate results than any other. The quantity of indigo-blue indicated by it is generally below the actual quantity contained in the sample. According to Berzelius this loss arises from the lime forming an insoluble compound with a portion of the reduced indigo- blue. Mr. Dale, however, is of opinion, that even when every precaution has been taken, a certain loss, proceeding from some hitherto unascertained cause, cannot be avoided. When, for instance, pure indigo-blue is treated with lime and copperas in the manner just described, the quantity which is again obtained by precipitation from any portion of the liquid is always less than what it should be by calculation, even when no excess of lime has been employed. 2. The second method of determining the indigo-blue is performed as follows : — About 15 or 20 grains of pure indigo-blue, obtained by precipitation from an indigo vat, and the same quantity of the indigo to be tested, which must be previously ground to a fine powder, are weighed off, and each of them is treated with about 12 times its weight of concentrated sulphuric acid in a flask or porcelain basin. After being heated at a temperature of 120' to 140" F. for about 24 hours, and occasionally well agitated, the two liquids are mixed with water, so that the volume of the two shall be exactly equal. Two equal measures of a weak solution of hypochlorite of lime are then taken, and to the first is added a quan- tity of the solution of pure indigo. The chlorine liberated by the excess of sulphuric acid in the solution destroys the blue color of the indigo-sulphuric acid. More of the solution must be added until the liquid begins to acquire a greenish tinge, and the number of measures necessary for the purpose is noted. The same experiment is then made with the solution of crude indigo. The quantity of indigo-blue in the latter is, of course, in inverse ratio to the number of measures which are requisite in order to take up the whole of the chlorine which is liberated. If, for example, the same quantity of hypochlorite of lime decolorizes 167 measures of the solution of pure indigo-blue and 204 measures of the solu- tion of crude indigo, then the quantity of indigo-blue contained in 100 parts of the latter is given by the following proportion — 204 : 167 : : 100 : x = SrS. A number of samples of indigo may be tested in this manner at the same time. Care must be taken to prepare a fresh solution of indigo-blue for every series of trials, since this solution undergoes a change on standing, which renders it quite inapplicable as a standard of comparison. It is necessary also to pay great attention at the moment when the green- ish color indicating an excess of the sulphate of indigo begins to appear, for it will often be found that this color disappears after standing a few minutes, and a fresh quantity of the blue solution must then be added cautiously, until the greenish tinge becomes permanent, even after standing for some time. Modifications of this process have been introduced by various chemists by the use of permanganate of potash, chlorate of potash, or bichromate of potash, in the place of hypochlorite of lime : but as the principle on which the process depends is in each case identical and the modus operandi is almost the same, it will be un- necessary to enter into any minute description of these modifications. The whole method is, l>owever, open to serious objections, and the results which it affords cannot at all be de- pended on. In the first place, it is difficult to institute a strict comparison between the dilFerent shades of color resulting from the decomposition of the sulphate of indigo in dif- ferent cases, since the pure green tinge observed when an excess of the pure sulphate has been added to the decomposing agent, gives place to a dirty olive or Ijrownish-green, when a solution of crude indigo is employed, in consequence of the impurities contained in the latter. Secondly, it is almost impossible to avoid tlie formation of a certain quantity of sulphurous acid during the action of concentrated sulphuric acid on crude indigo. This sulphurous acid during the following operation becomes oxidized before the blue sulphate is destroyed, and hence the percentage of indigo-blue is apparently raised. In employing this method, it is common to find more than 80 per cent, of indigo-blue in a good sample of indigo, whereas the best qualities seldom contain above 60 per cent., and average quali- ties between 40 and 50 per cent. This method may show a percentage of 70 indigo-blue, when the method first described indicates between 50 and 60. 3. The third method of estimating the indigo-blue is performed in the following manner : Equal weights of the samples to be tested are treated with equal quantities of concentrated sulphuric acid in the manner above described, and the solutions are then diluted with water and introduced into graduated glass cylinders, water being added to each until they all exhibit exactly the same shade of color. The richer the sample is in indigo-blue, the greater will be the quantity of water necessary for this ])urpose, the number of measures of water required in each ca.se indicating the relative amount. The great objection to this method consists in the circumstance, that the different kinds of indigo do not give the same shade of blue when their solutions in sulphuric acid are diluted with water, some exhibiting a pure blue color, others a blue with a greenish or purplish tinge. It tliereforc becomes difficult to institute an exact comparison between them. The ingredients necessary for setting the vat are copperas or protosulphate of iron, newly slaked quicklime, and water. Various proportions of these ingredients are employed, as for instance, 1 part by weight of indigo, (dry,) 3 parts of copperas, and 4 of lime ; or 1 620 INDIGO. of indigo, 2^ of copperas, and 3 of lime ; or 8 of indigo, 14 of copperas, and 20 of lime ; or 1 of indigo, f of copperas, and 1 of lime. The sulphate of iron should be as free as possible from the red oxide of iron, as well as from sulphate of copper, which would re- oxidize the reduced indigo-blue. The vat having been filled with water to near the top, the materials are introduced, and the whole after being well stirred several times is left to stand for about twelve hours. The chemical action which takes ])l:ice is very simple. The protoxide of iron which is set at liberty by the lime reduces the indigo-l^lue, and the indigo- white is then dissolved by the excess of lime, forming a solution, which, on being examined in a glas.s, appears perfectly transparent and of a pure yellow cokr, and becomes covered wherever it comes into contact with the air, with a copper-colored pellicle of regenerated indigo-l)luc. The sediment at the bottom of the vat consists of sulphate of lime, peroxide of iron, and the insoluble impurities of the indigo, such as indigo-brown in combination with lime, as well as sand, clay, &c. If an excess of lime is present, a little reduced indigo- blue will also be found in the sediment in combination with lime. The copperas vat is employed in dyeing cotton, linen, and silk. For cotton goods no other kind of vat is used at the present day. The dyeing process itself is very simple. The vat having been allowed to settle, the goods are plunged into the clear liquor, and after being gently moved about in it for some time are taken out, allowed to drain, and exposed to the action of the atmosphere. Whilst in the liquid the fabric attracts a portion of the reduced indigo-blue. On now removing it from the Tuiuid it appears green, but soon be- comes blue on exposure to the air in consequence of tlie oxidation of the reduced indigo- blue. On again plunging it into the vat, the deoxidizing action of the latter does not again remove the indigo-blue which has been deposited within and around the vegetable or animal fibre, but on the contrary, a fresh portion of reduced indigo-l)lue is attracted, which on re- moval from the liquid is again oxidized like the first, and the color thus becomes a shade darker. By repeating this process several times, the requisite depth of color is attained. This efiect cannot in any case be produced by one immersion in the vat, however strong it may be. The beauty of the d cinder from the heap after a few da vs' burning . V. Cinder squeezed out of the pudilHng bar dur ing the process of shingling. VI. Spec inien from a largo heap of thoroughly calcined cinder. 1 The experiments through which Mr. Nielsen's important discovery of the hot blast was introduced into the iron manuf\icfure, were made at the Clyde Iron Works, where the fuel 634 IKON. generally made use of was coke, derived from splint coal ; during its conversion into coke, this coal sustained a loss of 55 per cent. During the first six months of the year 1829, when all the cast iron in the Clyde Iron Works was made by means of the cold blast, a single ton of cast iron required for fuel to reduce it 8 tons 1;^ cwt. of coal, converted into coke. During the first six months of the following year, while the air was heated to near 300° F., 1 ton of cast iron required 5 tons 'S^ cwt. of coal converted into coke. The sav- ing amounts to 2 tons 18 cwt. per ton of iron, from which must be deducted the coal used in heating the air, which was nearly 8 cwt. This great success induced the Scotch iron masters to try a higher temperature, and to substitute raw coal for coke ; and during the first six months of the year 1833, the blast being heated to 600°, 1 ton of cast iron was made with 2 tons 5^ cwt. of coal. Add to this 8 cwt. of coal for heating, and we have 2 tons 13:^ cwt. of coal to make one ton of iron. An extraordinary impetus was given by this discovery to the iron manufacture in Scotland, where, from the peculiar nature of tlie coal, and from the circumstance that, with a heated blast, Mushet's blackband ironstone could be exclusively used, its importance was more highly felt than in England and \Valcs. According to Mr. Finch's statement, (Scrivenor's " History of the Iron Trade,") there were in 1830 only eight works in operation in Scotland, which made in that year 37,500 tons of pig iron; in 1838 there were eleven works, consisting of 41 furnaces, which made 147,500 tons, being an increase in eight years of 110,000 tons per annum ; in 1839, there were 50 furnaces in blast, making 195,000 tons ; in 1851, 750,000 tons of pig iron were made ; and in 1856, with 127 furnaces in blast, the make rose to 880,500 tons. The influence of hot blast has likewise been felt in the anthracite district of South Wales, where that coal is now successfully used, and where several furnaces have in consequence been erected. In short, notwithstanding tlie opposition with which the introduction of hot blast was met by en- gineers, as being destructive of the quality of the iron, so great have been the advantages derived from it, that at the present time more than ninetecn-twentieths of the entire pro- duce of the kingdom is made in furnaces blown with heated air. Mr. Truran, in his recent work on the iron manufacture of Great Britain, gives it as his opinion that the effects of hot blast have been greatly exaggerated, and that it is to improvements in the preparation of fuel and ore in the furnaces, in blowing engines, and in the smelting process, far more than to the heating of the blast, that we must refer the great reduction in the yields of coal in recent times ; he thinks that the comparatively large produce which has been obtained from the Scotch furnaces, is to be referred to the general use of carbonaceous ore, which melts at a low temperature, and which, from its compar- ative freedom from earthy matters, requires but a minimum dose of limestone for flux- ing. Against this opinion of an English writer on iron smelting we may place that recorded by an American metallurgist, Mr. Overman, who has written a large and in many respects a valuable treatise on the manufacture of iron, as conducted in America. " The economical advantages arising from the application of hot blast, casting aside those cases in which cold blast will not work at all, are immense. The amount of fuel saved in anthracite and coke furnaces varies from SO to 60 per cent. In addition to this, hot blast enables us to obtain nearly twice the quantity of iron within a given time tliat we should realize by cold blast. These advantages are far more striking with respect to anthracite coal than in relation to coke or to bituminous coal. By using hard charcoal, we can save 20 per cent, of fuel, and augment the product 50 per cent. From soft charcoal we shall derive but little benefit, at least where it is necessary to take the quality of the iron into consideration." The following tables, embodying the general results of an extended series of experi- ments on the relative strength and other mechanical properties of cast iron, obtained by the hot and cold blasts, are extracted from a report presented to the British Association (1837) by Messrs. Eaton, Hodgkinson, and William Fairbairn. Of the three columns of numbers, the first represents the strength or other quality in the cold blast iron, the second that in the Iiot, the third is the ratio of these qualities ; the fig- ures included in parentheses, indicate the number of experiments from which the results have been deduced. These results contain nearly the whole of the information afforded by the investigation. From the numbers in the tables, it will be seen that in Buffcry iron No. 1, cold blast some- what surpasses hot blast in all the following particulars :—l, direct tensile strength ; 2, compressive strength ; 3, transverse strength ; 4, power to resist impact ; 5, modulus of elasticity or stiffness ; 6, specific gravity ; while the only numerical advantage possessed by the hot blast metal is that it bends a little more than the cold before it breaks. In No. 2 the advantages of the rival kinds are more nearly balanced, still rather in favor of the cold blast. No. 3 hot blast Carron iron resists both tension and compression better than cold blast of the same denomination ; and No. 3 hot blast from the Devon works in Scotland is remarkably strong, while No. 3 cold blast is comparatively weal<, notwithstanding its high specific gravity. On the whole it would appear from the experiments, that while the irons of No. 1 have been somewhat deteriorated in quality by the hot blast, those of No. 3 have been benefited by its mollifying powers ; while those of No. 2 have been but very slightly IRON. 635 affected ; and from the evidence brought forward, it is rendered highly probable that the introduction of a heated blast, while it has, perhaps, to a certain extent, injured the softer irons, lias improved those of a liarder nature ; and considering the small deterioration that the irons of the quality No. 2 have sustained, and the apparent benefit of those of No. 3, together with the saving effected by the heated blast, there seems good reason for the pro- cess becoming so general as it has done. Carron Iron, No. 2. Tensile strength in lbs. per square inch Compressive streQgth in lbs. per inch, from cast- inijs torn asunder .----- Ditto, from prisms of various forms - . - Ditto, from cylinders - - . - Transverse strength from all experiments - Power to resist impact ------ Transverse strength of bars one inch square in lbs. Ultimate deflection of do. in inches . - - Modulus of elasticity in lbs. per square inch Specific gravity ...---- Devon Iron, No. 3. Tensile strength . . - - ... Compressive strength ------ Transverse do. from experiments generally Power to resist impact ------ Transverse strength of bars one inch square Ultimate deflection do. Modulus of elasticity ------ Specific gravity ------- Coed Talon Iron, No. 2. Tensile strength ..----- Compressive strength - - - - - - Specific gravity - - - . . . - Carron Iron, No. 3. Tensile strength .---•-- Compressive strength - - - . . - Specific gravity ..--•-- BuFFERY Iron, No. 1. Tensile strength - - Compressive strength ------ Transverse strensth ...... Power to resist impact --.--. Transverse strength of bars one inch square Ultimate deflection do. ------ Modulus of ela.sticity Specific gravity ------- 16,6S3 (2) 106,375 (3) 100,631 (4) 125,403 (13) - - (11) - - (9) 476 (3) 1-313 (3) 17,270,500 (2) 7,066 - - (5) - - (4) 448 (2) -79 (2) 22,907,700 (2) 7,295 (4) 18,8.55 (2) 81,770 (4) 6,955 (4) 14,200 (2) 115,542 (4) 7,135 (1) 17,466 (1) 93,366 (4) - - (5) - - (2) 463 (3) 1-55 (3) 15,331,200 (2) 7,079 Ratio, representing Cold lilnst by KKiO. 13,505 (3) I 1000 : 809 103,540 (2) I 1000:1020 100,733 (2) i 1000 : lool 121,085 (13) I 1000 : 970 - (13) j 1000 : 991 (9) 1000 : 1005 463 (3) 1000: 973 1-337 (3) 1000 : 1018 16,085,000 (2) 1000: 931 7,046 1000: 897 11^ 21,907 (1) 145,435 (4) - - (5) - - (4) 537 (2) 109 (2) 22,473.650 (2) 7,229 (2) 16,676 (2) 82.7.39 (4) 0,968 (4) 17,755 (2) 133,440 (3) 7,056 (1) 1.3,434 (1) 86,397 (4) - - (5) - - (2) 436 (3) 164 (3) 1-3,730,500 (2) 6,958 1000 : 1417 1000 : 2786 1000: 1199 1000 ; 1380 1000 : 981 1000: 991 1000: 884 1000 : 1012 1000 : 1002 1000 : 1250 1000 : 11.56 1000: 989 1000 : 769 1000: 9-25 1000: 931 1000: 963 1000: 942 1000 : 1053 1000: 893 1000: 989 The following general summary of results, as derived from the experiments of Messrs. Hodgkinson and Fairbairn on the transverse strength of hot and cold blast iron exhibits at one view the ultimatum of the whole investigation. R.atioof Stronsth —that of Cold Blast being rep- resented by 1000. Ratio of Powers to sust.ain Im- pact— Cold Blast being 1000. These irons are from Mr. Hodgkinson's experiments : — Carron iron. No. 2 ------ - Devon iron, No. 3------- Buffery iron, No. 1 These irons arc from Mr. Fairbairn's experiments : — Coed Talon iron. No. 2 Coed Talon ditto, No. 3 Elsicar and Milton, ditto ------ Carron ditto. No. 3 Muirkirk, No. 1 .-....- Mean -.....- 1000 : 990-9 1000 : 1416-9 1000 : 930-7 1000 : 1007 1000 : 927 1000 : 818 1000 : 1181 1000 : 9'27 1000 : 1005-1 1000 : 2785-6 1000: 962-1 1000 : 1234 1000 : 925 1000 : 875 1000 : 1201 1000 : 823 1000 : 1021-8 1000 : 1226-3 Dr. Thomp.son's chemical examination of several samples of hot and cold blast iron is appended to this report. According to the experiments of this distinguished chemist, iron smelted by hot. blast contains a greater proportion of iron, and a smaller proportion of silicon, carbon, and aluminum, tlian when smelted by cold air. The mean specific gravity of 8 speci- 636 IRON. mens of Scotch cold blast iron No. 1, was 6-7034 ; the mean of 5 specimens of hot blast from the Carron and Clyde iron works was 7.0623, so that the density of cold blast iron is less than that of hot. The mean of 6 analyses of cold blast iron No. 1, gave 3^ atoms of iron, 1 atom of carbon, silicon, and aluminum ; the proportion of these three constituents being very nearly 4 atoms of carbon, 1 atom of silicon, and 1 atom of aluminum ; conse- cjuently Scotch cold blast iron consists of 20 atoms of iron, (with a little manganese,) 4 atoms of carbon, 1 atom of silicon, and 1 atom of aluminum. The mean of 5 analyses of hot blast iron No. 1, gave 6i atoms of iron and manganese to 1 atom of carbon, silicon, and aluminum, from which it would appear that cast iron smelted with a heat blast is purer than when the blast is cold. This, however, is not the case, as the numerous analyses of both varieties that have been made during the last few years concur in proving. Hot blast gray iron smelted with mineral coal contains a much higher percentage of silicon than the same variety of cast iron smelted from the same ores by cold blast ; in other respects, provided the process of reduction is complete, i. c. when little or no iron passes off with the slag, there is very little chemical difference between the two varieties, as will be seen in the fol- lowing table, which contains the results of a series of analyses of hot and cold blast iron, which we have lately had occasion to make, under circumstances peculiarly favorable for instituting the comparison, the furnaces working with the same ores, and making the same class of iron, viz. good No. 3 gray pig. Analyses of Cast Iron No. 3, smelted by Hot Blast. (Dr. Noad.) I. II. 1 III. IV. V. VI. VII. VIII. llenn. Silicon ... Graphite ... Sulpbar - Phosphorus - Met! 2-500 3-5-20 0-045 0-313 illic iron 3-140 I 3-380 3-100 3-210 0-090 0-079 0-422 0-308 per cent. 2-440 3-102 0-069 0-394 3-200 3.340 0-072 0-422 3-190 3-320 0046 0-4S0 8-120 3-340 0-072 0-320 93-15 2-260 3294 064 0-374 2 900 3-290 0-067 0-379 Analyses of Cast Iron No. 3, smelted by Cold Blast. (Dr. Noad.) Silicon Graphite - Sulphur - Phosphorus I. II. III. IV. V. VI. VII. VIII. Mean. 1-0.10 3-370 0-024 0-210 llic iron 1-400 3-1S4 0-037 0-314 per cent. 1-029 3-270 0-045 0-387 0-940 3-140 traces 0-361 1-372 3-333 0-029 0-372 1-486 3-274 0-037 0-872 1-466 3-242 0-028 0-342 90-0 1-400 3-197 024 0-354 1-268 3251 0028 0-339 The true reason of the frequent inferiority of hot blast iron has been correctly given by Mr. Blackwell. Furnaces blown with heated air exert greater reductive power than those in which a cold blast is used. This has led, since the introduction of hot blast, to the ex- tensive use in iron smelting of refractory ores not formerly smelted, a large part of which have been ores of a class calculated to produce inferior iron, and it is to the use of ores of this nature, far more than from any deterioration in quality, arising from a heated blast, that this inferiority of hot blast iron is to be ascribed. Utilization of the waste gases given off from the furnace head. — The agent in the blast furnace by which the oxide of iron is reduced, is carbonic oxide, the presence of which, therefore, in great excess is indispensable to the operation of the furnace. The flames rising from the tunnel head, which make a blast furnace at night such an imposing object, are occasioned principally by the combustion of this gas, on coming into contact with the oxygen of the atmosphere ; the attention of practical men was first called to the enormous waste of heat which this useless flame entailed by Messrs. Bunsen and Playfair, and the application of the gas to a useful purpose may be ranked noxt to that of the heated blast, :is the most important of the recent improvements in the iron manufacture. The gases evolved from iron furnaces where coal is used as the fuel, contain the following constituents, viz. : nitroge?i, ammonia, carttouic acid, carbonic oxide, light carbiirettcd hydrogen, ohfiant gas, ciirburetted hydrogen of unknown composition, hydrogen, sulphuretted hydrogen, and n//neons vapor. The nature of the combustible gas stands in a relation so intimate to the (hanges suffered by the materials put into the furnace, that its different composition in the various reigons of the furnace indicates the changes suffered by the materials introduced as tlicy descend in their way to the entrance of the blast. Now as the examination of this column of air in its various heights in the furnace must be the key to the questions upon which the theory and practice of the manufacture of iron depend, it was of the first im- portance to subject it to a rigid examination ; this accordingly has been done by the above- named eminent chemists, and subsequently by Ebclmen. We shall return to a consiikra- tion of the results they obtained presently, confining our attention at present to the compo- sition of the gases at the mouth of the furnace, and to the methods which have been adopt<'(l to utilize them. lEOX. 637 In order to arrive at a knowledge of the composition of these gases, M. Bunsen first studied minutely the phenomena which would ensue were the furnace filled with fuel only : by a careful distillation of a linown weight of coal, and analyzing of the products, he ob- tained results embodied in the subjoined table : — Carboii 68-925 Tar - - 12-230 Water 7-569 Light carburetted hydrogen - - - - - 7-021 Carbonic oxide 1-135 Carbonic acid ....---- 1-073 Condensed hydrocarbon and olefiant gas - - - 0-753 Sulphuretted hydrogen .--..- 0-549 Hydrogen 0-499 Ammonia 0-211 Nitrogen 0-035 100-000 Now, in the furnace, the oxygen introduced by the blast is consumed in the immediate vicinity of the tuyere, being there converted into carbonic oxide, and the coal loses all its gaseous products of distillation much above the point at which its combustion commences, near in fact, the top of the furnace ; the fuel with which the blast comes into contact is, therefore, colce, and upon calculating the amount of carbonic oxide produced by the com- bustion of 68-925 per cent, of carbon, and the nitrogen of the air expended in the combus- tion, we get as the composition by volume of the gases escaping from a furnace filled with Gasforth coal the following : — Nitrogen 62-423 Carbonic oxide -.-----• 33-163 Light carburetted hydrogen 2-527 Carbonic acid .-..---- 0*139 Condensed hydrocarbon 0-151 Sulphuretted hvdrogen 0-091 Hydrogen - " 1-431 Ammonia -- ....--- 0-070 100-000 With this preliminary information, Bunsen proceeded to calculate the modification of the gaseous mixture occasioned by the introduction into the furnace of iron ore and lime- stone. The materials used for the production of 140 lbs. of pig-iron were : — 420 lbs. calcined iron ore ; 390 lbs. coal ; 170 lbs. limestone. From 100 parts of the coal, 67-228 parts of coke were obtained ; but from this must be deducted 2-68 ashes, and ri8 carbon entering into combination with the iron ; which leaves as the quantity of carbon actually burnt into carbonic oxide before the tuyere 63-368 ; part of this carbonic oxide undergoes oxidation into carbonic acid at the expense of the oxygen in the oxide of iron which it reduces; a further quantity of carbonic acid is derived from the limestone; so that the gases returned to the mouth of the furnace by the combustion of the 07-228 parts of coke, the reduction of the corresponding quantity of ore, and the decomposition of lime- stone, consist of — Nitrogen 282-860 Carbonic acid 59-482 Carbonic oxide 121-906 404-248 Add to this the products of the distillation of the coal, and we get the following as the percentage compositions by weight and measure of the gases issuing from the mouth of the furnace. Nitrogen - Carbonic acid . - - - - Carbonic oxide Light carburetted hydrogen Hydrogen -.---- Condensed hydrocarbon - Sulphuretted hydrogen - - - Ammonia 100-000 100-000 Bv weight. By volume 59-559 - - 00-907 12-705 - 8-370 26-000 - - 20-846 1-397 - 2-536 0-078 - 1-126 0-108 - - 0112 0-053 - 0-045 0-054 - - 0-058 638 IRON. The calculations of the quantity of heat capable of being realized in the furnace by the combustion of the furnace gases are founded on the data on the heat of combustion given in the posthumous papers of Dulong, according to which — 1 kilogramme or 15,444 grains of Carbon burning to CO, heats 15,444 grains of water to 1499°C CO» 7371° Carbonic oxide 2502° Hydrogen - 34706° Light carburetted hydrogen 13469° defiant gas - - - , 12322° Sulphuretted hydrogen 447 tJ° Ammouia 6060° Using these numbers it is found that by the combustion of 100 of the furnace gases there are generated from the 5'J-55'J nitrogen 0000 12-705 carbonic acid 0000 26 Out; carbonic oxide C5067 1-397 carburetted hydrogen 18826 0-078 hydrogen 2704 0-108 olefiant gas 1331 0-053 sulphuretted hydrogen 2G8 0-034 ammonia 208 88374 = units of heat rtenerafcd, the nnit being understood to mean the amount of heat necessary to raise 1 kilogramme = 2-204 lbs. = 15,444 grains of water from 0° centigrade, to V cent. The amount of heat realised in the furnace is limited to that produced by the expenditure of the oxygen, corresponding to 59-559 nitrogen in the production of carbonic oxide ; this amounts to 20,001 units : hence follows the rcniarkable conclusion, that in the furnace which was the subject of experiment, not less than 81-54 per cent, of the fuel is lost in the form of combustible matter still fit for use, and that only 18-46 per cent, of the whole fuel is realized in carrying out the processes in the furnace. The temperature which should be produced by the flame of the furnace gases when burnt with air, is found by dividing the units of heat, viz. 883-74 arising from the combus- tion of 1 kilogramme of the gases by the number resulting when the quantity of the prod- ucts of combustion is multiplied by their specific heat (1-9338 x 0-2696) : we thus get the number 3083° F. ; but this is below the truth, inasmuch as there is an accession of combus- tible gases at the mouth of the furnace, arising from the decomposition of the liquid prod- ucts of the distillation of the coal in its passage over the red-hot fuel. Making proper cor- rection for this, and using numbers derived from actual experiments, Messrs. Bunsen and Playfair calculated the tenjperature of the gases when generated imder favorable conditions at 3214° F., and even this may be increased to 3632° F., a temperature far above that of cast iron, by the using a blast sufficiently heated. In utilizing these waste gases, care must be taken not to remove them from the furnace till they really are vaste, that is, until they have done their work in the furnace; it is obvious that no combustible matter could be removed from the lower regions of the furnace without seriously deranging the operations essential to the reduction and smelting of the ore. In order to remove the gases eftectually, and without injm-y to the working of the furnace, and in such a state as will permit their coriil)Usfi()n to l)e ed'ected with most advantage, the height of the furnace must be raised, the full width of the mouth being retained, and the gases nnist be withdrawn sufficiently fiir below the mouth for them to be obtained dry, and also beneath the point where they begin to enter into combustion from contact with the atmospheric air. Various modes of collecting the gases have been tried ; the best seems to be that adopted at Ebbw Vale, Sirhowy, and Cwm Celyn. A funnel shaped casting, equal in its largest diameter, to the throat of the furnace, projects into the interior a depth of 4 or 5 fVct ; the orifice at the liottom from 3 to 5 feet in diameter is closed by a conical casting, the apex upwards, from which a cliain proceeds to a lever liaving a counterpoise at the other end. (8ee /?>/. 338.) The materials are filled into the funnel-shaped receptacle, and are charged into tlie furnace with a uniform distribution, by lowering the cone by means of suitable machinery, which again returns it to its place when emptied. The circular space around the funnel, inside the furnace, forms a chamber for the reception of the gases, from wliich they are conveyed by brick tunnels or iron piping to the place of combustion. The wliole arrangement will be clearly understood by an inspection of the accompanying plans, fif/x. 340, 341, 342, 343, 344, kindly furnished to the writer by the proprietor of the Cwm Celyn and Blaina Iron Works. IRON. 639 Fig. 342 shows the plan of extracting the gases which is adopted at the Brymbo Iron Works, near Wrexham, the same being the patent of C. E. Darby. 340 ^ 341 342 It consists of a large pipe or tube inserted into the middle of the top part of the furnace, which descends a short distance down into the materials, and is carried over the top of the side of the furnace in the form of a syphon, a continuation of which pipe is taken to the boilers, or hot-air stoves, where the gas is burned in the usual way. The principal advantage claimed by this method is tliat it puts no check on the free escape of the gases, by which the driving of the furnace is impeded, and the quality of the iron deteriorated. The pat- entee estimates the saving of fuel with two furnaces making 240 tons of iron per week, by applying the gas to the blast engine boilers and hot-air stoves, at £1,200 a year. Thus : — Consumption of fuel at engine and stoves equal to 7 cwts. of good coal per ton of iron, made at 3.V per cwt., is 2s. OkZ ., say 2.t. per ton on 12,480 tons, or £1,248. The causes of derangement in the working of blast furnaces when the gases are drawn off to be utilized elsewhere, have been diligently studied by Mr. George Parry, of Ebhw Vale ; and he has kindly furnished us with the following resume of his observations, for insertion in this article. The manner in which the waste gases were formerly collected, was by sinking an iron tube, 7 feet deep, into the throat of tlie furnace, the diameter of the tube being about 3 feet less than that of the throat, thus leaving an annular i^pnce of 18 inches between the walls of the furnace and the sides of the tube. From this space the gases were allowed to pass off by the pressure within tlie furnace, through a pipe which penetrated the ring and walls. When the tube was kept full of minerals, about i or J only of the gas escaped into t!ie open air, the rest passing into tlie annular chamber ; and when this state of things was continued, those troublesome adhesions of masses of semifused materials, above and around the boshes, technically termed " .scaffolds," occurred, with the usual accompaniments of l)lack cinder and inferior iron. It is evident that when the tube was kef)t full of minerals, the contents acted as a loose stopper to the current of hot gases forced up by pressure from beneath, and diverted them towards the annular space where there was no such resistance, thus leaving the minerals in tlie central parts of the furnace in.suflicicntly snp|)lied with the upward current, and consequently with heat ; the minerals, on the other hand, surrounding this cold central cone, were supplied with more than their usual (luantity of boat, as w:is evidenced by the burning of tuyJires, and by the destruction of the brickwork in their neighborhood. In this state of things the ores in the external portions of the furnace would 640 IRON. become reduced and converted into gray metal ; while those in the central portions would, according to the degree of deviation of the ascending current of heated gases from them descend to the point of fusion either thoroughly deoxidized, and slightly carbonized, or possibly with a portion still in the state of oxide, and mixing there with the properly reduced ores, enter into fusion with them, producing a mixture of irons which must necessarily prove of inferior quality, and a black cinder from the unreduced oxides. When the iron tube in the throat of the furnace was kept only partially filled with minerals, much more gas escaped into the open air, as might have been expected, and consequently more trav- ersed the central parts of the furnace ; and it was always observed that when that mode of filling was adopted, the furnace worked much better : but then the object, viz. that of 343 economizing the gases, was not attained. Differently formed furnaces were found to be dis- turbed in different degrees by this system of drawing off the gases : the old conical narrow topped furnaces were affected very much less than the improved modern domed top furnace of large capacity, from which all attempts to take off any useful portion of the gases proved absolute ruin. It might be argued, that as the same quantity of blast and fuel was used as heretofore, the ascending current of heated gases ought to produce the same deoxidizing and carbonizing efFect on the superincumbent mass, whatever direction they might take in making their escape at the upper region of the furnace ; for if the central part should not have been sufficiently acted upon, the external annulus would have more than its usual IROiT. 641 share of chemical influences. But when it is considered that iron is only capable of taking up a certain quantity of carbon, and no more, it follows that after having received this dose, its further exposure in the external parts of the furnace where the hated gases abound 344 can do nothing towards supplying the deficiency of carbon in the metal reduced in the cen- tral part. From these considerations, it became evident that no system of drawing off the gases aroimd the sides, whether by the insertion of an iron tube into the throat, or by lat- 345 era! openings through the walls into a chamber surrounding the top of the furnace, can be adopted without more or less injury to its action ; and that the only unobjectionable mode Vol. III.— 11 642 IRON. would be to take the gases from a chamber above the surface of the minerals, thus equaliz- ing the pressure on the whole sectional area of the mouth, and thereby allowing an equally free flow for the ascending current up the middle, as well as up the sides of the furnace. By this method the whole of the waste gases would become utilized, instead of a portion only and the fiuii'^ee would be restored to its original state, inasmuch as the direction of the flow of heated gases would not be interfered with by unequal resistance. To form this cham- ber, the furnace must be covered in, and fed through a hopper, a plan long adopted at the Codner Park Iron Works, with the supposed advantage of scattering the minerals around the sides of the furnace, and preventing their accunmlating in the centre ; a conical charger of this description, but lixed in the throat of the blast furnace, was in use at the Cyfartha Works, more than half a century ago, the minerals being thrown by baskets to the centre of the cone, and allowed to roll down to the sides of the fuinace, thus giving a cup Ibim to the surface of the minerals, the larger lumps of course rolling to the centre, and afiording a freer passage in that direction for the upward current. It was not, however, until January, 1851, that a trial was made at the Ebbw Vale Works, of an apparatus of this description lor collecting the gases. It was then supplied to one of the old forms of ('onical furnace with a narrow top, and the trial proved eminently successful, the furnace producing any quantity of iron reijuired according to the burden, as usual. Several other furnaces were similarly fur- nished in and around the neighborhood, and it was now thought that the principle of taking oft' the gases from a chamber above the surface of the mineraL\ together with the conical mode of charging, were the only indispensable conditions to success for all furnaces ; and some even which were originally built too narrow at the mouth, were actually improved by the new method of charging, which did not allow of the surfaces of the njincrals rising higher than about 6 feet I'rom the top ; thus giving to the furnace a diminished height, and as a consequence of its conical shape, a wider mouth. Further experience, however, de- monstrated the fallacy of this general conclusion. A large domed furnace was furnished with the same kind of charging apparatus which l)roved so successful in former instances, but to the astonishment of all it turned out a com- plete failure, the same derangements occurring as in the former cases, where a portion of the gases only was collected, by sinking a tube into the throat. Kow this furnace could not be filled to within 6 or 7 feet of the top, and at that depth the diameter was 13 ft. 6 in., owing to the sliarp sweep of the dome ; the actual working furnace was therefore 37 feet high, instead of 44 feet, with a mouth 13 ft. 6 in., instead of 8 ft. ; and as the minerals can- not lie so close against the smooth sides of the walls as they do locked in each other in the more central region of the furnace, a much freer discharge of the gases up the sides must take place ; and on boring a hole through the side of the furnace, in the neighborhood of the boshes, it was found that 2 feet in, the coke and other minerals were at a white heat, but a little further on towards the centre, lumps of black blazing coal were found, with ironstone which had not even attained a red heat. The charging apparatus was now raised with the furnace 5 feet, and the minerals drawn up an inclined plane to the chargiiig cup, thus enabling it to be kept full to within a short distance of the old mouth, after which the furnace worked a.s usual. That diminished height was not the cause of the bad working of the furnace was afterwards proved, the furnace having been blown out for repairs, and re- lined with brickwork, giving it that form and proportion deemed necessary, from the expe- rience gained ; the height being now only 37 feet, instead of 44, and the diameter of the mouth 7 ft. 6 in., or one-half of that at the boshes. The same charging apparatus which failed before, mounted G feet above the mouth, was used, and the furnace has now been working uninterruptedly for 5 years, turning out as much as 160 tons of gray pig iron per week, or when burdened for white iron, '200 tons ; economizing the whole of its gas, and as much under the control of the manager as any furnace, either closed top or open top, can reasonably be expected to be. It is clear, therefore, that the covering of the top has nothing whatever to do with the action of a furnace kept full to the mouth, and having the proper form and proportions from that point downwards. The month must be understood to be that part of the furnace which represents the mean height of the surface of the min- erals, and not the top of the masonry, and the question arises, what proportion should that bear in diameter to the boshes or widest part, and what the latter should be with reference to height in order to secure a maximum economical effect on the quality of the iron made, and on the yield of fuel. This state of perfection can exist only when the isothermal lines in the furnace are parallel to the horizon •, tlie temperature of the minerals at any given height above the tuyeres being the same through the whole horizontal sectional area at that height, and consequently arriving at the zone effusion in an equally prepared state. If the mouth of the furnace be too wide, the heated gases have a greater tendency to pass up the sides than through the centre, thus destroying the liorizontality of the lines of equal temper- ature, and giving them a curved form with the convex side downwards ; hence ores of differ- ent temperatures, and of various stages of preparation, will occupy any given horizontal sectional area of the furnace ; these descending together, and mixing in the zone of fusion, will produce evils in proportion to the extent of the deflection of the curves from a hori- IRON. 643 zontal line. On the contrary, if the mouth of the furnace be too narrow in proportion to the other parts, we may expect an undue portion of the gases to pass up the centre, leaving the minerals around the sides comparatively unacted upon. It is easy to see that evils of the same kind as before must exist here, the isothermal lines becoming now concave downwards, instead of convex, giving as before, through any horizontal section of the fur- nace, ores at various temperatures, and at different degrees of deoxidation or carburation, according to the depth which they may have attained in the furnace. There are several instances of furnaces originally built with too narrow tops, being greatly improved by widening them ; this may conveniently be done by feeding them through a conical charger, which by lowering the surface of the minerals virtually increases the width of the mouth : on the other hand, furnaces having the opposite defect of being too wide at the top, may be benefited to some extent, provided the walls are nearly perpendicular, or do not widen too rapidly downwards, by employing as large a cone as it is possible to work in the throat ; for by the use of this feeder the minerals must fall close to the sides, and the larger lumps roll to thejixis of the furnace, and so facilitate the passage of the gases in that direction, besides giving to the surface a concave or cup form, and consequently a diminished height and resistance to the upward current in the middle. This principle of improving the charg- ing of such defective furnaces is even carried out to some extent in feeding open top fur- naces where the gases are wasted. The charging plate is so placed as to prevent the nose of the barrow from projecting any distance into the furnace ; the minerals being thus dis- charged close to the edge, the larger lumps have a tendency to roll over towards the centre, leaving the smaller at the ring walls, to check the upward current in that direction. The above considerations will materially assist in furnishing an answer to the oft re- peated and very important question, " What form and proportion should a blast furnace have to produce the best results in quality of iron, and in economy of fuel, whether worked on the open top principle, or enclosed for the purpose of utilizing the waste gases ? " Ex- perience has proved that when the mouth of the furnace is one-half tlie diameter of the widest part, good work is obtained, and that any deviation from that proportion, if in excess, has been productive of great derangement in its action. The height of the furnace should also bear a certain proportion to the greatest diameter, in order to secure a uniform flow of tlie ascending current through all its parts ; for if the widest part bear too great a rela- tion to the height, the boshes nmst necessarily be of a low angle, and consequently the minerals around the sides near their top be at too great a distance out of the direct line of passage of the ascending current, and consequently remain only partially prepared for fusion. The proportions recommended by Mr. Parry, and which have been practically tested most satisfactorily in several instances, are as shown infig. 346. The mouth 6' b' one-half the diameter of the widest part c c, and this should not be at a less depth than its own diameter. The sides of the furnace to this depth should be formed slightly dome-fashioned, for the purpose of giving to that region a larger capacity than would be obtained by a conical form. The radius of the curve should be at right angles to the axis of the furnace, and formed by a prolongation of the line represent- ing the greatest diameter. When tiie radius is set at a great angle with this line, which is often done to give greater capacity to the domed part, the distortion produced by the sharpness of the curve may leave a segment of the minerals unacted upon by the gases in their passage to the mouth, and entail greater evils than would be compensated for by increased capacity. The curve is continued below the widest part of the furnace till it meets the top of the boshes d d, the angle of which should not be less than 70°, and start from the point of the tuyeres//. The depth also from tlie widest part to the tuyeres should not be less than its own diameter plus half the diameter of the tuyeres. These proportions give a blast furnace, of any determinate height fixed upon, the largest possible capacity it is capable of receiving, while remaining free from any distortion of form, likely to give a place for minerals to lie out of the way of the action of the upward gaseous current ; when the height exceeds the proportion to its greatest diameter indicated in the figure, an unnecessary sacrifice in its capacity is the only loss entailed. The height above the mouth must be regulated by the kind of hopper used for cliarging, where it is intended to carry off tlie gases. Doubtless when the true principle of collecting these gases without injury to the blast furnace becomes more generally known, attention will be directed to the easiest and most convenient mode of introducing the minerals. Tlie conical charger has only one disadvan- tage, that namely of allowing a great waste of gas during the charging ; probably some kind of revolving hopper may be contrived to remedy this defect. It is of course assumed that 346 644 IRON. the furnace is supplied with a proper quantity of blast, and of a density proportionable to the diameter across the tuyeres, so as to maintain a vigorous combustion of the fuel to tlje very centre of the hearth, the top of which is indicated by the letters e e, for unless this is attained, a cold cone of minerals will remain in the centre, and produce derangements wiiich no degree of perfection in the form of the furnace in the higher region can remove. Thevry of the blast furnace. — Analyses of the gases from a furnace at Alfreton in Der- byshire, at various depths below the surface, gave to Messrs. Bunsen and I'layfair the re- sults embodied in the subjoined table. The furnace was supplied with 80 charges in the course of 24 hours, each charge consisting of 390 lbs. of coal, 420 lbs. of calcined ironstone, and 170 lbs. of limestone, the product being 140 lbs. of pig iron. The gases were collected through a system of tubi's of malleable iron, 1 inch in diameter, and were received in glass tubes, 4 inches long, and J of an inch in diameter. The well-known skill of M. Bunsen as a gas analy.st is a guarantee of the accuracy of the determinations. Composition of the Gases taken from different depths in the Furnace. I. II. III. IV. V. VI. VII. VIII. IX. 5 feet. 8 fi-et. 11 feet. 14 feet. 17 feet. 20 feet. 23 feet. 24 feet. 34 feet. Nitr(ij.'en Carlionic aciil Carbimic oxide Light carbiiretted 1 hyilriiL'en ) TIv(iro2eii Olefianttras - Cyanogen 65-35 7-77 25-97 8-75 6-73 0-4:i 0-00 54-77 9-42 20-24 8-23 6-49 0-85 0-00 52-57 9-41 23-16 4-57 9-33 0-95 0-00 5095 910 19-3 6-64 12-42 1-57 0-00 55-49 12-43 lS-77 4-81 7-62 1-3S 0-00 60-46 10-83 19-43 4-40 4-S3 00 0-00 58-28 8-19 29-97 1-64 4-92 0-00 trace 56-75 10-08 25-19 2-33 5-65 00 trace 5805 00- 37-43 0-00 3-18 0-00 1-84 From these analyses it appears : — 1. That at a depth of 34 feet from the top, within 2 feet 9 inches of the tuyere, the gas was entirely free from carbonic acid, but contained an appreciable quantity of cyanogen. 2. That t!ie nitrogen is at a minimum at 14 feet. 3. That carburetted hydrogen is found so low as 24 feet, indicating that, at that depth, coal must be undergoing the process of coking. 4. That hydrogen and olefiant gases are at a maximum at 14 feet. 5. Tliat the proportions between the carbonic acid and carbonic oxide are irregular, which is probably to be explained by the fact that water is decomposed as its vapor passes through the layers of hot coal. The average composition of the gases evolved from the materials used in the blast fur- nace is somewhere between the two following numbers : — Nitrogen - - - - Carbonic acid - - - Carbonic oxide Light c;irburetted hydrogen Hydrogen ... Olefiant gas Sulphuretted hydrogen Ammonia - - - 60-907 57-878 S-STO 9-823 26-846 24-042 2-536 2-743 1-126 4-972 0-112 0-392 0-045 0-035 0-058 0-115 100-000 100-000 The proportion of nitrogen to oxygen as an average deduced from these analyses is 79-2 to 27. The product of the combustion of coal gives the same proportions as those ex- isting in atmospheric air. Viz: 79.2 : 20.08. The excess of oxygen must therefore depend upon the carbonic acid of the limestone, and the oxygen of the ore given to carbon during the process of reduction. Now, as at a depth of 2-1 feet the gas collected contained 27-6 and 26-5 oxygen to 79-2 nitrogen, it is held that at this depth the gas must already have ac- cumulated all the oxygen of the ore, and the carbonic acid of the limestone ; and the con- clusion is drawn that, in hot blast furnaces fed with coal, the reduction of the iron and the expidsion of the carbonic acid from the limestone take place in the boshes of the furnace. The exact region of the furnace in which the melting of the iron and the formation of slag are afTected is not exactly defined, but it is assmned thiit the point of fusion is at the top of the hearth. The region of reduction in a furnace smelting with coal must be much lower than when the fuel is coke or charcoal, because a large portion of the body of the furnace must be taken up in the process of coking, and the temperature is thereby so depressed, that it is sufficient neither for the reduction of the ore, nor for the expulsion of carbonic acid from the limestone. The mean general results obtained by M. Ebelmen from a charcoal furnace at Clerval are given below. The methods of analysis adopted by this chemist were altogether different IKON. 645 from those employed by Messrs. Bunsen and Playfair. in the Annales dex J/««es, vol. six. p. 89, 1851. For details we refer to his memoir No. of analysis - L IL IIL IV. V. VI. VII. Depth below mouth - 3 ft. 3 in. 3 ft 3 in. 9 ft. 9 in. 9 ft, -9 in. 19 ft. 6 in. 19 ft. 6 in. 27 feet. Tymp. Carbonic acid . . - Carbonic oxide - - - 1 Hydrogen - - - - Carburetted hydrogen ' Nitrogen - . - - 12-111 24-60 5-19 0-93 57 -^-^ 11-95 23-85 4-31 1-33 5S-56 4-14 i 31-56 i 3-04 0-:i4 1 60-92 4-23 81-84 2-77 0-77 60-89 0-49 35-0O 1-06 0-36 63 04 0-07 35-47 1-09 0-31 63-06 0-00 87-65 1-13 0-10 61-22 Oi)3 89 -se 0-79 0-^5 58-17 Totals loO.OO 42-5 100-00 100-uO 100-00 100-00 luO-00 100-00 100-00 Oxygen, per 100 nitrogen - Carbon vapor, per 100 nitrogen ... 40-3 32-7 32-7 2S-5 28-2 30-7 35-8 32-8 31-7 29-6 29-6 2S-5 28-5 30-T 35-9 I. Gas taken a short time after the introduction of the charge : II. the same taken a quarter of an hour after charging : III. gas collected through a ca.st-iron tube four inches in diameter ; it rushed out with a noise and gave a sheet of flame, carrying with it particles of charcoal and dust : IV. gas collected by boring the masonry ; it rushed out violently, burning with a blue-colored dame : V. the same taken an hour after : VI. gas collected by boring the masonry at the back of the furnace about 3i feet above the tuyere; it burnt with a white flame, giving olF fumes of o-^iide of zinc ; it was collected through porcelain tubes : VII. gas collected through gun-barrels lined with porcelain ; it was evolved with sufficient force to project scoriae and even cast iron. The furnace was working with cold bla.«t under a pressure of -44 inch of mercury. The charges had the following composition : — Charcoal, 253 lbs. ; minerals, (various,) 397 lbs. ; limestone, 254 lbs. Thirty-two charges were driven in twenty-four hours ; the furnace was stopped after every twenty charges ; the produce being 3,970 lbs. of black cast iron ; the daily neld being about 6,175 lbs. Tiie experiments show that while the carbonic acid progressively diminishes downwards, the carbonic oxide progressively increases, the former altogether disappearing at a depth of 27 feet. On examining the numbers representing the oxygen and carbon referred to 100 nitrogen, it is seen that they diminish progressively to a depth of 19 feet, the oxygen com- bined varying from 42.5 to 28.2. The proportion of carbon in the same zone rises from 28-5 to 32 8 ; a result brought about as much by the carbonic acid disengaged from the minerals as from the gaseous products of the distillation of the charcoal. It is seen that the reduction of the mineral is already considerably advanced at the depth of 19i feet ; and this, so to speak, without any consumption of charcoal, but through the conversion of car- bonic acid into carbonic oxide. The hydrogen decreases as the carbonic oxide increases ; showing that this gas exercises no influence in the reduction of the ore. The results obtained by M. Ebelmen from a coke furnace at Seraiug were as under : — No. of experiment - - - I. II. III. IV. V. VL Depth 1 foot 1 foot 4 feet 9 feet 10 feet 10 feet 12 feet 45 feet Carbonic acid - - - - Carbonic oxide ... Hydrogen .... Carburetted hydrogen - Nitrogen .... 11-39 28-61 2-71 0-20 5706 11-39 2S-93 304 58-64 9-8.') 28-06 0-97 1-48 59-64 1-54 as S3 0-69 1-43 62-46 1-08 35-2 1-72 o-as 61-67 1-13 35-35 2 -OS 0-29 61-15 0-10 86-30 201 0'>5 6134 0-00 45-05 0-25 007 54-63 Totals .... 100-00 100-00 100-00 100-00 100-00 10000 100-00 liiO-OO Oxygen, per 100 nitrogen 45-0 45-6 40-0 29 6 30-2 80-6 29-9 41-2 Carbon vapor, per 100 nitrogen 352 35-7 330 29-4 29-6 30-0 29^ 41-3 I. Gas obtained by plunging an iron tube, three centimetres in diameter, about one foot into thfr furnace : II. the same; the gas burnt .spontaneously: IV. two consecutive anal- yses of the same g.as : V. the gas was collected by an iron tube : VI. gas collected by piercing the m;isonry two feet above the tuyeres ; the gas was accompanied by fumes of cyanide of p )ta.le. The balls, even when made, will not bear much heat under the hammer without falling to pieces, hence an imperfect weld in the hammered mass and rolled bar is tlie result, and although the iron may be chemically pure it is deficient in strenr/lh. By protracting tiie process and wasting more iron, there is no doubt but that the iron nmjht be improved, for the cinder 652 IRON. would become richer in oxid^, more fluid, and consequently offer less resistance to a perfect weld. Iron, on the contrary, with a small percentage of silicon may be " balled up" directly it is " dried," and the short time required, for that operation can be conducted at the highest heat of the furnace. A good welding of the mass is the consequence : such ii-on is atrong^ and the labor of the puddler in obtaining it is much less than in the former cise. Every pound of silica must have twice its weight of iron to form a cinder sufficiently rich in oxide to allow the particles of iron to become properly agglutinated. t>ueh being the influence of silicon on both the yield and the strength of wrought iron, and such being the waste attendant on its removal in the refinery, it becomes an object of much practical importance to prevent as far as possible the formation of a silicide of iron in the blast fur- nace, and the observations of MM. Janoyer and Gauthier on this point require careful verification. Manganese. — The presence of this element in pig-iron does not appear to exert much influence either for good or for bad on the quality of the metal, and even when it exists in ([uantity amounting to 4 or 5 per cent, in the crude iron, it disappears almost entirely (luring the conversion of the cast-iron into wrought or malleable. It has already been ob- served that the cinder from iron smelted from manganiferous ores contains, generally speaking, more suli)hur than .'^lags or cinders from iron ores containing no manganese. We have had numerous opportunities of confirming this, and have therefore on this account alone attached much importance to the existence of manganese in iron ores ; but our at- tention has more recently been directed to another point which we think especially worthy of notice of iron manufactures, namely, to the almost jierfect removal of pliosphorus from pig-iron containing a very large proportion of that element, and at the same time a high percentage of manganese. As our experiments on this important point are still in prog- ress, we shall merely here quote a few in illustration of the purifying action we have alluded to. Iron made from a highly phosphorized ore containing no manganese : — Phosphorus per cent. Pig 3030 Puddled bar 0-838 Rough down bar - 0.572 The finished bar was cold short in the highest degree ; it was, in fact, nearly worthless. Iron made from a highly phosphorized ore containing a large percentage of man- ganese : — Phosphorus. Manganese. Pig - - - - - 2.00 7-20 Puddled bar - - - 030 ) ^.„^ Do. - - - 0-20 r^° Finished bar - - - O'll The iron was carefully watched during the puddling process. It melted very thin, and took rather more work than usual ; as soon as the boiling commenced it was very violent, the metal forcing itself out of the door hole until it was checked. When it " came to nature," as the workmen term it, it worked beautifully and stood any amount of heat ; in fact, the heat could with difficulty be raised to the retiuisite degree. The yield was 22 cwts. 2 (|rs. 24 lbs. of pig to produce 1 ton (of 20 cwts.) of puddled bar ; this is about the yield of good mine iron when properly puddled. The finished bar exhibited none of the cold short quality, it was exceedingly ductile, indeed excellent horseshoes were made from it. The puddling cinder had the following composition : — Silica 8-240 Protoxide of iron 70-480 Oxide of manganese 12'800 Phosphoric acid 7-6CO Sulphur '535 99-715 Other observations have shown that highly manganiferous pig (without phosphorus) is puddled with difficulty, and sometimes with considerable waste, so that the advantages of an alloy of manganese would seem to be confined to thosie varieties of crude iron into the composition of which phosphorus largely enters. JTie Conversion of Crude or Carburized Iron into Malleable Iron. — This is effected by one or more operations, which are necessarily of an oxidizing nature, the object being to eliminate from the cast-iron the carbon in the form of carbonic oxide gas, and the silicon, sulphur, phosphorus, and other foreign bodies in the form of oxidized products, which pass either partially or wholly into the scoria; or cinders. The pig-iron is either subjected to a preliminary dccarburation^ the oxidizing blast hearth, or " refinery," and the opera- IROK 653 tion thus commenced afterwards completed in the oxidizing air-furnace, or " puddling fur- nace ; " or the complete conversion of the crude iron is effected by one operation in the puddling furnace, by the process called " boiling." It is said {Blackwdl) that, at several works abroad, the attempt to arrest the progress of decarburation in the puddling or boil- ing furnace at that point in which the conversion has proceeded only so far as to leave the iron in the state of steel, or subcarburet, has been successful, and that a valuable natural or puddled steel, not requiring cementation before conversion into refined or cast steel, has been the result. English Method of refining. — The finery furnace is composed of a body of brick-work, about 9 feet square,' rising but little above the surface of the ground. The hearth, the bottom of which is of millstone grit, placed in the middle, is 2^ feet deep ; it is rectangu- lar, being in general 3 feet by 2, with its greatest side parallel to the face of the tuyeres, and it is made of cast-iron in four plates. On the side of the tuyferes there is a single brick wall, on the three sides sheet-iron doors are placed, to prevent the external air from cooling the metal, which is almost always worked under an open shed or in the open air, but never in a space surrounded by walls. The chimney, from 15 to 18 feet high, is supported upon four columns of cast-iron ; its lintel is 4 feet above the level of the hearth, in order that the laborers may work without restraint. The air is supplied by the blowing cylinders which supply the blast furnace, and enter the hearth through 6 tuyeres, so arranged that the current issuing from those on the opposite sides of the crucible are not disposed in the same plane. These tuyeres, like those in the furnaces in which cast-iron is made, are pro- vided with double casings, through which a current of cold water is constantly flowing, and each pipe is furnished with a suitable stop-valve for regulating the volume of the blast. The tuyeres are placed at the height of the lip of the crucible or hearth, and are inclined towards the bottom, at an angle of from 25" to 30°, so as to point upon the bath of melted metal as it flows. The quantity of air blo\vn into the fineries is considerable, being nearly 400 cubic feet per minute for each finery. The ground plan of a finery is shown in fig. 347, A being the hearth, b the tapping hole, b the chill mould, and a a a a a a the nozzles of the tuyeres. The operation of refin- ing crude iron is conducted as follows : A fire is lit in the centre of the hearth, which is first urged by a gentle blast ; a charge of pig, about 2 tons, is then laid on, and the whole is covered up dome- form witha heap of coke ; the full power of the blast is now turned on, the cast-iron melts, and flowing down gradually collects in the crucible, more coke being added as the first quantity burns away. The operation proceeds by itself, the melted metal is not stirred about as in some modes of refinery, and the temperature is always kept high enough to preserve the metal liquid. Dur- ing this stage the coals are observed continually heaving up, a movement due' in part to the action of the blast, but in part to an expansion caused in the metal by the discharge of carbonic oxide gas. When all the pig-iron is collected at the bottom of the hearth, which happens in about two hours, it is blown vigorously for some time ►longer, the tap-hole is opened, and the /?«e metal runs out with the slag into the chill mould, or pit, as it is called, which has been previously wa.shed with a thin clay liquid, to prevent the refined metal from adhering to its surface. Tlie chill mould is in a prolongation of the tapping hole ; it is a heavy cast-iron trough, about 10 feet long, 3 feet broad, and 2 to 2i inches deep. The slag, from its inferior specific gravity, forms a crust on the surface of the metal : its separation is facilitated by tin-owing cold water in large quantities on the fluid mass immediately that the entire ciiarge has left the refinery. This sudden chilling of the metal makes it exceedingly brittle, so that it can be broken into smaller pieces by heavy hammers, for the subsequent operation of puddling. The rjfined metal is very white, hard, and brittle, and possesses in general a fil)rous radiated texture; or sometimes a cellular, including a considerable number of small si>herical cavities, like a decomposed amygdaloid rock. The loss of iron in the refinery process is very large, varying from 10 to 2i) per cent. In the Welsli iron works, 1 ton of wjiite iron takes from If to 2 hours to refine, the consumption of coke being from tj to S cwts., and the loss about 3 cwts. Gray iron takes from 7 to 9 cwts. of coke per ton, the time rctpiired to refine being from 2^ to 3 hours, and the loss of iron ])er ton 4 cwt. The pig-iron to be decarburized in the refinery is freiiuently mixed with rich silicates, (forge cinders,) and occasionally with oxides of 654 IRON. iron, the object being to protect the melted metal in some degree from the oxidizing effects of the blast, and to react on the carbon which it contains. The quantity einployed depends on the degree to which the pig-iron is carburized. The crude iron from which wrought iron of the bc*t quality is produced, is that possessing a medium degree of carburation, or what is generally termed gray pig-iron. White iron, which possesses an inferior degree of fluidity to gray pig- iron, and which comes as it is termed more rapidly to nature, is that quality which is most generally em[)loyed in the manufacture of wrought iron, especially when the conversion is effected in the single operation of boiling in the puddling furnace ; but this species of pig- irou being the result of imperfect reactions in smelting, is always more impure than gray iron obtained from the same materials, and docs not produce wrought ii on of the best quality. The colce employed in the refinery should be as free as possible from shale, and should contain only a low percentage of ash ; it should especially be free from sulphuret of iron, which it often contains in considerable cpiantity, as it is found that nearly the whole of this sulphuret enters into combination with the metal, and docs not pass off in the slags. Refineries arc sometimes worked on hot fluid iron, run direct from the hearth of the blast furnace, a considerable saving, both of time and fuel, being hereby cfi'ected. Various proposals have been patented for the employment of fluxes to assist in the removal of the impurities of cast-iron, both in the refining and puddling furnaces. Thus Jlr. Hampton patented, in 185.5, a flux, prepared by slaking quicklime with the solution of an alkali, or alkaline salt. • MM. Du Motay and Fontaine propose, in a patent secured in 1856, to purify and decarbonize iron in the refining and puddling furnace, by the employment of fluxes prepared from the scoria; of the puddling furnace, from oxides of iron and silicates or carbonates of alkalies, or other bases. Mr. Pope (1856) proposes to add the residue ob- tained by the distillation of Boghead or Torbane mineral, to such fuel as is eniploycd in the refining of iron. Mr. Sanderson, of Sheffield, (1855,) employed for the refining of iron such substances as sulphate of iron, capaUe of disengaging oxygen or other elements, which will act upon the silicium, aluminium, kc, contained in the metal. These and various other .schemes have been suggested with the object of lessening the enormous waste which pig-iron undergoes on its pas.«age through the refinery ; for as the process is at present conducted, the partial elimination of the carbon, sulphur, phosphorus, kc, is only effected at the expense of a large quantity of iron, which is oxidized by the blast, and passes in the form of silicate into the slag; the desideratum is the discovery of some method of reducing the oxide of iron, and substiiutiiig for it some other base,which will form with silica a sufficiently fusible silicate. Mi-, lilackwell suggests that the decarbura- tiou of pig-iron might be effected by remelting it in a cupola furnace, either alone, or with minerals containing nearly pure oxides of iron ; the oxide of iron would be reduced by the carbon of the pig-iron, while the silicates of the fuel, with the silica, alumina, and other easily oxidizable alloys eliminated from the cuide iron, would be sepaiated in the form of fusible earthy glass. The employment of stc;im as a purifying agent for crude iron has been patented by several persons. Mr. Xasmyth in 1854 obtained a patent for the treatment of iron in the puddling furnace with a current of steam, which being introduced into the lower part of the iron, passes upwards, and meeting with the highly heated metal undergoes decomposition, both elements acting as purifying agents. The steam employed is at a pressure of about 5 pounds per square inch, and pas.ses into the metal through a species of hollow rabble, the workman moving this about in the fused metal until the mass begins to thicken, which occurs in from five to eight minutes after the introduction of the steam ; the steam pipe is then removed and the puddling finished as usual. The advantages are said to consist in the time saved at each heat or puddling operation,* (from ten to fifteen minutes;) the very effective purification of the metal; and the possi- bility of treating iiighly carbonized pig-iron at once in the puddling furnace, the preliminary refining being thus avoided. In October, 1855, Mr. Bessemer patented a somewhat simi- lar process for the conversion of iron into steel, the steam highly heated, or a mixture of air and steam, being forced through the liquid iron nui from the furnace into skittle jxits. Steam being u.sed only at an early stage of tlip process, and the treatment finished with heated air. In the early part of the same year Jlr. Martien, of New Jersey, obtained a natent for a partial ])urification of crude iron, by causing air or steam to pass up thrcuigh the liquid metal, as it flows along gutters from the top hole of the furnace or finery forge ; and he subsequently proposed to include with the air or steam, other purifying agents, such as chlorine, hydrogen, and coal gas, oxides of manganese, and zinc, &c. Other methods of treating crude iron with air and steam were made the subjects of patents by Mr. Be.asemer in December 1855 and January 1856. In October a patent for the en.ploy- ment of steam in admixture with cold blast in the smelting furnace and fining forge, was obtained by Messi-s. Armitage and Lee, of Leeds, and in August a patent was obtained by Mr. George Parry, of the Ebbw Vale Iron Works, for the purification of iron by means of highly heated steam. The fluid iron is allowed to run into a reverberatory furnace pre- viously heated, and the steam is made to impinge upon it from several tuyeres, or to pass IRON. 655 through the metal. Steel is to be obtained by treating highly caiburetted iron with the steam, and then running it into water, and fuzing it with the addition of purifying agents, or adding to it in the furnace a small quantity of clay, and afterwards about 10 or 15 per cent, of calcined spathose ore. Mr. Parry observing that when steam was sent through the molten iron, as in Mr. Nasmyth's proces-?, the iron quickly solidilied, conceived the idea of communicating a high degree of heat to the steam by raising the steam pipe a couple of inches a'>ove the surfice of the metal, so that it might be exposed to the intensely heated atmosphere of the furnace ; and also of inclining the jet at an angle of 45', so a.s to give the molten mass a motion round the furnace while the pipe was maintained in the sa;ue position at a little distance beyond the centre : when this was done, in a fev.- minutes the iron began to boil violently, the rotatory motion of the fluid bringing every pai t of it successively into contact with the highly heated mixture of steam and atmospheric air, and soliditication taking place. Having thus ascertained the proper way of using steam as a refining agent, it Ov'curred to Mr. Parry that, as the presence of silicon in tl;e pigs for puddling aftects in a remarkable degree the yield of iron, as well as its strength, it is a matter of consequence that this element should be removed as completely as possible pre- vious to the puddling operation ; the steaming of the iron would probably therefore be more protltably applied in the refinery than in the puddling furnace. Pig-iron containing 3 per cent, of silicon gives 6 per cent, of silica, which, to form a cinder sufficiently fluid to allow the balling up of the iron, would require from 10 to 12 per cent, of iron ; and this can, of course, only be obtained by burning that amount of iron in the puddling furnace, after the expulsion of the carbon, and while the mass is in a powdery state. The super- heated steam is injected on the surface of the iron in the refinery i*. water tuyeres, similar to those used for hot blast at smelting furnaces ; they are inclined at an angle of about 45" ; some are inserted at each side of the door of the furnace, and are pointed .so a3 to cross each other, and give the iron a circulating motion in the furnace. The tuyeres are from f to + an inch in diameter ; a little oxide of iron or silicate in a state of fusion on the surface of the iron accelerates the action, as in common refineries, and increases the yield of metal, but to a much greater extent than when blasts of air are used. The steam having been turned on, the mass of iron commences circulating around the inclined tuyeres, and soon begins to boil, and the action is kept uniform by regxdating the flow of the steam. The most impure oxides of iron may be used in this process, such as tap cinder or hammer slag from puddling furnaces, without injury to the quality of the refined mctnl made ; the large quantities of sulphur and phosphorus which they contain being eflectually removed by the detergent action of the heated steam. When 4 cwt. of cinders are used to the ton of pig, 20 cwt. of metal may be drawn, the impurities in the pig being replaced by refined iron from the cinders. We have had several opportunities of witnessing this beautiful refining process at the Ebbw Vale Iron Works, and have made the following analysis of the cinders and metal, which fully bears out the above statements : — Graphite . . - . Silicon .... Slag Sulphur .... Phosphorus - - - - Manganese - - - - Sulphur .... Phosphoric acid - A ton of gray iron may be refined by steam in half an hour, using seven jets of steam •| of an inch in diameter, and with a pressure of from 30 to 40 lbs. ; the temperature of the steam being from Gt'O' to 700^ F., the orifices of the tuyeies being 2 or 3 inches above the surface of the iron. As the fluidity of the metal dei)ends upon the heat which it is receiving from the combustion of the fuel in' the grate, and not on any generated in it by the action of the steam, it is evident that the supi>ly of the latter in a given time must not exceed a certain limit, or the temperature of the fluid iron will become reduced below that of the furnace. This, however, partly regulates itself, and does not require much nicety in the management, for, if too much steam be given, the ebullition becomes so violent as to cause the cinders to flow over the bridges, giving notice to the refiner to slack his blast. The " forge cinders " used in the steam refinery contain 6t') per cent, of iron; the "run out" cinder contains only 26; 40 per cent, of iron, or thereabouis, have therefore been converted into refined metal, and the resulting cinder is as pure as the ordinary Welsh mine, witii its yield of 25 per cent of iron. The following is the result of one week's work of the steam refiuerv : — Pig iron. Eefincd metal. - 2-40 . - 0-30 - 2-68 . - 0-32 - 0-68 . . 0-00 - 0-22 . . 0-18 - 0-13 . . 0-09 - 0-86 - - 0-24 Forjre cindor.<; thrown Cinder rnn out of into tlie r^-linerv. tlic refinery. - 1 -34 - - 0-16 - 2-0(J - - 0-129 656 IRON. Pigs used Metal made Loss cwt. qrs, lbs. 396 15 393 3 1 2 1 14 350 o; 349 Yield 20 14 The quantity of cinder (puddling) used was 3^ cwt. per ton of pig. When l^ cwt. of cinders were used to 1 ton of pig, the yield was invariably 20 cwt. over a malie of about \00 tons. lu'Jiuinff b>/ (jaf, {German method.) — The most simple form of gas reverberatory furnace is that known as Ecii's furnace, which is employed at the government works of Gloi- witz and Konigsliiitte, for refining iron made on the spot. Tlie i'ollowing description and plan of this furnace is extracted from a report to the secretary of state for war, from tlie superintendent of royal gun factories, Colonel Wilmot, R. A., and the chemist of the War Department, Profes.>;or Abel. The gas generator (which replaces the fireplace of the ordinary reverberatory furnace) i.s an oblong chamber, the width of which is 3 feet 9 inches, and the height 348 from the sole to the commencement of the sloping bridge 6 feet 4 inclies. It tapers slightly towards the top, so as to Jacihtate the descent of the fuel, which is introduced through a lateral opening near the top of the geucr;itor. Its cubical contents are about 44 feet. The air necessary for the production of the gas is supplied by a feeble blast, and enters the generator from the two openings or tuyeres of a long air chest of iron phite {Jigs. 348, 349, 35u) fixed at the back of the cham- ber, near the bottom. The space between the air chest and the sole of the chambers serves as a receptable for the slag and ash from the fuel. There are openings on the other side of the chamber, opposite the tuy- eres, which are generally closed by iron plugs, but are required when the ijl ife==t: : tuyeres have to be cleaned out. There is an opening below the air-chest, ' ' ' through which fire is introduced into the chamber, when the furnace is set to work, and wliich is then bricked up, until at the expiration of about 14 days it becomes necessary to let the fire die out, when the slag and ash which have accumulated on the sole of the chamber are removed through this opening. The hearth of the furnace is constructed of a somewhat loamy sand ; its general thickness is about 6 inches ; its form is that of a shallow dish, with a slight incline towards tlie tap hole; the iron is prevented from pen- etrating through the hearth by the rapid circulation of cold air below the fire-bridge and the plate of the hearth. Figs. 351 and 352 represent the upper oblong air-chest pro- vided with a series of tu}6res, whicli enter the top of the furnace just over the fire-bridge at an angle of 30". The air forced into the furnace through these tuyeres serves to inflame and burn the gases rushing out of the generator, and the direction of the blast throws the resulting flame down upon the metal on the hearth, in front of the bridge. This air-chest communicates, like the other one, by pipes, with the air accumulator of the neighboring blast furnace. The amount of pressure employed is about 4 lbs. ; but the supply of air, both to the generator and the inflammable gases, admits of accurate regulation by means of valves in the eoimecting pipes. There is an opening in the arch at both sides of the furnace, not far from the bridge, into which, at a certain stage of the operations tuyeres are introduced, (being placed at an angle of 25,°) :dso connected with the blast apparatus and provided with regulating valves. The refining process is conducted as follows : — The hearth of the furnace having been constructed or repaired, a brisk coal fire is kindled in the generator, through tlie opening at the bottom, which is afterwards bricked up. About 2o cubic feet of coals are then introduced from above, and the necessary supply of air admitted to the generator through the lower air-chest. When these coals have been thoroughly ignited, the generator is filled with coals, and a very moderate supply of air admitted tlirough the tuyeres below, (for the generation of the gas,) and those over tlie bridge, (lor its combustion.) until the furnace is dried, when the supply of air at both places is increased, so as to raise the hearth to the temperature necessary for baking it thoroughly, upon which, about 40 cwt. of iron are introduced, the metal being distributed over the whole hearth as uniformly as possible, and the size of the pieces being selected with the view to expose as much sur- 351 u 352 & IROIf. 657 face as possible to the flame. The fusion of the charge of metal is effected in about three hours, the coal used amounting to about 3f cubic feet per hour. The gas generator is always kept filled with coal, and the supply of air admitted from below is diminished by a regulation of the valve, whenever fresh coal is supplied, as the latter, at first, always Eck's Gas Eeverberatoiy Furnace.— Front view. .•^^•''-- LoDgitudinal Section. yields gas more freely. The arrangement of the upper row of tuyferes effects the com- bustion of gases just as they pass from the generator on to the hearth. The hottest portion of the furnace is of course near the fire-bridge, i. c, where the blast first meets with the gases. During the melting process the iron is shifted occasionally, so that the Vol. III.— 12 658 IROX. cooler portion near the flue may in its turn become melted without loss of time. When the iron is ascertained to be thoroughly fused, about 6 lbs. of crusted Hniostone are thrown over its surface for the purpose of converting the dross which has separated into Cross section at c, d, on Plan. fusible slag. The two side tuyeres are now introduced into the furnaces through the openings above alluded to, the width of the nozzle employed depending upon the power of the blast used. The air rushing from these tuytires impinges with violence upon the IKON". 659 iron, and, the two currents meeting, an eddying motion is imparted to the fused metal. In a short time the motion produced in the mass is considerable ; the supernatant slag is blown aside by the blast, and the surface of the iron thus exposed undergoes refinement, while it changes continually, the temperature of the whole miss being raised to a full white heat, by the action of the air. The iron is stirred occasionally, in order to insure a proper change in the metal exposed to the action of the blast. A shovelful of lime- stone is occasionally thrown in, (the total quantity used being about 1 per cent, of the crude iron employed.) The slag produced is exceedingly fusible, and is allowed to re- main in the furnace until the metal is tappud, and on cooling it separates from it completely. The duration of the treatment in this furnace after the metal is fused, varies from two hours and a half to five hours, according to the product to be obtained. For the prep- aration of perfectly white iron, the treatment is carried on for five hours. A sample is tapped to examine its appearance, when it is believed to be sufficiently treated. When the charge is to be withdrawn from the furnace, the side tuyere nearest the tap hole is withdrawn, so that the blast from the opposite tuyere may force ihe metal towards the hole. Tlie fluid iron, as it flows from the taphule, is fully white hot, and perfectly limpid ; it chills, however, very rapidly, and soon solidifies. A few pails of water are thrown upon those portions of the metal which arc not covered with the slag, which flows out of the furnace, the object being to cool it rapidly, and thus prevent the oxida- tion of any quantity of iron. Tlie loss of metal during the treatment is said not to ex- ceed 5 per cent. With regard to the purification which the iron undergoes in the gas reverberatory furnace, it appears to be confined chiefly to the elimination of carbon and silicium, the amount of sulphur and phosphorus undergoing but little alteration, as appears from the following analysis {Abel) : — Pig iron. Eeflned iron. Silicium ... - 4-66 - - - 0-62 Phosphorus - - - 0.56 - - - 0-50 Sulphur - - - - 0-04 - - - 0-03 Nevertheless the iron thus refined is highly esteemed for all castings which are required tg possess unusual powers of resistance : some experiments made to ascertain the com- parative strain borne by the refined metal, and the same metal as obtained from the blast furnace, showed the strength of the former to be greater by one half than that of the latter. T/ie operation of puddling. — In the years 1783 and 1784, Mr. Ilenry Cort of Gosport obtained two patents, one for the puddling, and the other for the rolling of iron, "dis coveries," says Mr. Scrivenor, " of so much importance in the manufiicture, that it must be considered the era from which we may date the present extensive and flourishing state of the iron trade of this country." The object of Mr. Cort's processes was to convert into malleable iron, cast or pig iron, by means of the flame of pit-coal in a common air furnace, and to form the result into bar by the use of rollers in the place of hammers. The process was managed in the follow- ing manner: — "The pigs of cast iron produced by the smelting furuace are broken into pieces, and are mixed in such proportions according to their degree of carbonization, that the result of the whole shall be a gray metal. The mixture is then speedily run into a blast furnace, where it remains a suflicicnt titne to allow the greater part of the scoriie to rise to the surfiice. The furnace is now tapped, and the metal runs into moulds of sand, by which it is formed into pigs, about half the size of those which are broken into pieces. A common reverberatory furnace heated by coal is now charged with about 2^ cwt. of this half-refined gray iron. In a little more than half an hour, the metal will be found to be nearly melted; at this period the flame is turned off", a little water is sprin- kled over it, and a workman, by introducing an iron bar through a hole in the side of the furnace, begins to stir the half-fluid mass, and divide it into small pieces. In the course of about 50 minutes from the commencement of the process, the ii'on will have been re- duced by constant stirring to the consistence of small gravel, and will be considerably cooled. The flame is then turned on again, the workmen continuing to stir the metal, and in three minutes' time the whole mass becomes soft and semifluid, upon wiiich the flame is then turned off. The hottest part of the iron now begins to heave and swell, and emit a deep lambent blue flame, which appearance is called fernientalion ; the heav- ing motion and accom[)aiiying flame soon spread over the whole, and the heat of the metal seems to be rather increased than diminished for the next quarter of an hour ; after this period the temperature again falls, the blue flame is less vigorous, and in a little more than a quarter of an hour the metal is cooled to a dull red, and the jets of flame are rare and faint. Din-ing the whole of the fermentation the ., and when his patents were completed, the leading irimmasters of the country contracted to pay him lo.f. a ton for their use, so that he would not only have been repaid, but munificently rewarded, had he not unfortunately connected himself with a man named Adam Sellicoe, chief clerk of the Navy Pay Office, who proving to be a de- faulter, committed suicide, having previou.sly destroyed the patents and the agree- ments with ironmasters belonging to his partner, Henry Cort. Upon the death of Selli- coe, the premises, stock, and entire eflects of Cort were soM by a siunniary iirocess ob- tained bv the Navy Pay Ofllce, and the unfortuiuite man was thus completely ruined. For description of puddling furnace, see Iron, vol. i. The I'uddlinij process. — Various patents have been taken out within the last four or five years for the employment of chemical agents to assist in the i)urification of iron in the puddling furnace. One of the latest is that of M. Charles Pauvert of Chatelleraidt, who proposes to employ a cement composed of the following substances: — oxide of iron, U parts; highly alununous clay, 30 parts; carbonate of potash, 1 part; carbonate of soda, 1 i^art. The iron is to be placed with the cement in layers, and heated in the fur- nace in the ordinary manner. After cementation it is welded, and then drawn into bars; it is stated to become thus as soft and tenacious as iron made from charcoal. Shaf haiult's compound, for which a patent was secured in 1835, is said by Overman to furnish very satisfactory results, and where competent workmen are employed, a good furnace is said IR02T. 661 to make a heat in two hours, producing neither too much nor too little cinder in the fur- nace. The compound consists of common salt, 5 parts; oxide of manganese, 3 parts; fine white plastic clay, 2 parts. The pig is heated as in common operations. It is melted down by a rapid heat, the damper is closed, and the cinder and metal diligently stirred. In the mean time the above mixture, in small parcels of about half a pound, is introduced in the proportion of one per cent, of the iron employed; if, after this, the cinder doea not rise, a hammer slag (rolling mill cinder) may be applied. The ^^ Boiling" process. — In this operation, which was the invention of Mr. Joseph Ilall, pig iron is converted into malleable iron without the intervention of the refinery, and without any excessive waste: it is, therefore, of great value, especially as it allows of the use of better qualities of pig iron than those usually employed. The construction of the "boiling" furnace does not materially differ from that of the "puddling" furnace, except in the depth of the hearth, that is, in the distance from the work plate below the door to the bottom plate, which, in the former, is double, or nearly so, that of the latter. In the puddling furnace the distance between the bottom and top seldom exceeds twenty inches, while in the boiling furnace it varies from twenty to thirty. \\\ puddling the furnace is charged with metal alone, but in boiling cinder is charged along with the metal, and the temperature rises much higher. The bottom of the furnace is covered with broken cinders from previous workings, or with the tap cinder from the puddling furnace which has been subjected to a process of calcination in kilns; this material, which constitutes an admirable protection to the iron plates of the furnace, is called by t\ie workmen " bull dog ; " its preparation was patented by Mr. Hall in 1839. It is made in the following manner : the tap cinder from the paddling furnace is placed in layers in a kiln, and so arranged that a draught shall pass through from the fire holes on one side to those on the other : the kiln is filled up to the top with broken cinders, and over the whole is laid a layer of coke ; about the third or fourth day, the more fusible part of the cinder begins to run out of the bottom holes, leaving in the kiln a fine rich porous silicate of iron, which is the substance used for lining the boiling furnace, the fluid portion being rejected. In 8 or 10 hours the "bull dog" is melted by the intense heat of the furnace, covering the bottom, and filling up all the interstices in the brickwork ; the heat is now somewhat lowered by diminishing the draught, and the charge of pig (from Z\ to Ah cwts.) introduced in fragments of a convenient and uniform size, together with 30 or 40 lbs. of cinder ; the doors of the furnace are now closed, and all access of cold atmospheric air prevented, throwing fine cinder or hammer slag roimd the crevices, and stopping up the work hole with a piece of coaL In about a quarter of an hour the iron begins to get red-hot; the workman then shifts the pieces so as to bring the whole to a state of uniformity as regards heat. In about half an hour the iron begins to melt ; it is con- stantly turned over, and at intervals of a few minutes cinder is thrown in ; the surface of the mass is seen to be covered with a blue flame ; it soon begins to rise ; a kind of fermentation takes place beneath the surf\ice, and the mass, at first but 2 inches high, rises to a height of 10 or 12 inches, and enters into violent ebullition. During the time that this " fermentation" is taking place, constant stirring is required to prevent the iron from settling on the bottom. The boiling lasts about a quarter of an hour ; after which the cinder gradually sinks, and the iron appears in the form of porous spongy masses of irregular size, which are constantly stirred to prevent their adhering together in large lumps, to facilitate the escape of the carbon, and to separate the cinder, which, when the operation has been successfully conducted, flows over the bottom apparently as liquid as water. The iron is now " balled up," as in the operation of puddling. The objections to the boiling process are : the wear and tear in the furnace which occurs in treating gray pig iron, particularly that of the more fluid description ; the slowness of the operation, and the amount of manual labor which it entails to produce good results. In some works the crude iron is run directly into the boiling furnace from the blast furnace, by which nnich saving of coal is effected, and a product of a more uniform quality obtained; but the labor of the workman becomes more oppressive from the additional heat to which he is subjected from the close proximity of the blast furnace. Ironmasters are not agreed as to the respective merits of the "boiling" and "puddling" systems; some maintain that the former is more economical than the latter, which involves " refining ; " others think that boiling iron has a tendency to communicate to it the " red short" quality. According to the observations of Mr. Trnran, in several works where both methods are employed, the largest quantity of iron is first passed through the refinery. Mr. ITall, the inventor of the boiling system, in descanting on the merits of his pro- cess, describes how, with the same pig. the iron may be made weak and cold short ; or tough, ductile, and malleable. For the first proceed thus : — Pass the pig through the refinery, then puddle agreeably to the old plan on the sand bottom ; that is, melt it as cold as possible; drop the damper quite close before the iron is all tnelted, dry the iron as expeditiously as may be, with a large quantity of water; and, lastly, proceed to ball 662 lEON. in a proper number of "young" balls ; the result will be a Tcry inferior quality of inanu- foctured iron. On the other hand, to produce a malleable iron of very superior quality first charge the furnace with good forge pig iron, adding, if required, a sufficiency of flux, increasing mr diminishing the same in proportion to the quality and nature of the pig iron used. Secondly, melt the iron to a boiling consistency. Thirdly, clear the iron thoroughly before dropping down the damper. Fourthly, kce[) a plentiful supply of fire upon the grate. Fifthly, regulate the drauglit of the furnace l)y the damper. Sixthly, work the iron into one mass, before it is divided into balls ; when thus in balls, take the whole to the hammer as (luickly as possible, after which roll the same into bars. The bars, being cut into lengths, and piled to the desired weights, arc then heated in the mill furnace, welded and compressed by passing tlirough the rolls, and thus furnished ibr the market. In this way, from the pig to the finished mill bar, one entire process, that of the refinery, is saved. Mr. Hall states that, by his process, he can obtain malleable iron of any character, (premising that the ores from which the pig is smelted are of good quality,) from tiie softness of lead to the hardness of steel, and further that he can exhibit difl'erent qualities in the same bar, one end being crystalline, nearly as brittle as glass, the other end equal to the best iron that can be produced for fibre and tenacity, wliile the middle exhibits a character approximating to both ; and as a further illustration of the excellence of the iron that may be made by the "pig boiling" process, he refers to a specimen in the Geological Museum, Jermyn Street, London, labelled " Specimen of two and a quarter inch romid iron, tied cold, manufactured at the Bloomfield Iron Works, Tipton, Stiiilordshirc." This specimen has been called a " Staftbrdshire knot ;" it was made from a bar two inches and a quarter in diameter, and nearly seven inches in cir- cumference ; also to a " Punched Bar," half inch thick, made at one process for the smithy, commencing with a half-inch punch, and terminating with one six and a half, without exhibiting the slightest fracture. Mr. Hall was led to the discovery of the "boiling" principle, by noticing the ex- ceedingly high fusion which took place on subjecting puddling furnace slag to a high degree of heat, and the excellence of the bloom of iron produced by the operation ; it occurred to him, that if such good iron could be made from cinder alone, a very superior product ought to be obtained from good pig iron, with equally good fluxes, and the result of experiments fully answered his expectation, though for along time he was unable to make his discovery practically useful, on account of the difficulty of getting furnaces constructed capable of rendering the intense heat required, and the corroding action of the fluxes. Puddling furnaces were then made of brick and clay, with sand bottoms. He succeeded at last by lining the interior of the furnace with iron, and pro- tecting it with a coating of prepared tap cinders. In America, the "puddling" and "boiling" processes are both in use. Overman gives preference to the latter as being the most profitable, but it can only be employed to a limited extent for lack of cinder ; in a rolling mill forge, therefore, half the furnaces are employed for boiling, and half for puddling, the latter supplying cinder for the former. In the eastern States, where the fuel is anthracite, double puddling furnaces are employed and a blast is used, the incombustibility of this variety of coal rendering it impossible to get the requisite heat by merely the draught of the chimney. lu/. 359 represents an - a59 anthracite furnace bisected vertically through the grate, hearth, and chimney. It differs from the ordinary puddling furnace chiefly in the greater depth of the grate, which is made to contain from twenty to twenty-four inches of coal, and in the lesser height of the chimney, which, as a blast is employed, need only be sufficiently high to carry the IKON. 663 hot gases out of the furnace ; the letters a, a, a, a, a, indicate the position of the iron cross binders, which serve to bind together the cast-iron plates of the enclosure, and to prevent the siuiiiiig of the roof from the expansion and contraction of the brickwork. The blast machines are fans, the best form of which is shown in 360 Jiff. 360. (Overman.) The wings of this fan are encased in a sepa- rate box ; a wheel is thus formed, which rotates in the outer box ; the figure shows a horizontal section through the axis. The wings are thus connected, and form a closed wheel, in which the air is whirled round, and thrown out at the peri- phery. The inner case, which re- volves with the wings, is fitted as closely as possible to the outer case, at the centre near a, a, a, a. The speed of the wings is some- times as much as 1,S00 revolutions per minute. The motion of the axis is produced by means of a leather or india-rubber belt and a pulley. This variety of fan is used at the puddling furnaces at Ebbw Tale, where the fuel is small coal. Fig. 361 is a horizontal section of the double anthracite puddling furnace. The grate measures 3 feet by 5. The width of the furnace externally is from 5+ to 6 feet. The hearth is usually 6 feet in length. It has two work doors, one directly opposite the other. Two sets of workmen are required therefore at the same time ; double the quantity of metal is charged, and the yield is twice that of a single furnace ; the economy is in the room, fuel, and labor ; one good puddler only being required to manage the operation. Double puddhng furnaces are also used in several works in England, but as Mr. Truran observes, the economical advantages attending them in point of fuel are lost if the pnddlers do not work well to time : they must bring their heats to the respective stages simultaneously, for if one is kept waiting for a short period by the other, the loss in iron more thah balances the reduced consumption of coal. This difiiculty of obtain- ing men who will work well in concert has operated against the use of the double furnace, which would otherwise certainly supersede the single, as, combined with the process of running the iron in liquid from the blast furnace, the consumption of fuel is under the one-half of the quantity demanded with single furnaces working cold iron. Puddling furnaces are sometimes constructed with what are called " water boshes." The hearth is surrounded with heavy cast-iron plates, in which is formed a passage of an inch or an inch and a half bore, through which a current of cold water is caused to flow, the object being to protect the furnace from the destructive action of the heat and cin- der. Overman found such furnaces to work well with fusible metal such as is produced from a heavy burden on the blast furnace, or from ores containing phosphorus; but with iron requiring a strong heat, such as results from a light burden on the blast fur- nace, or when it contains impurities firmly and intimately combined, puddling furnaces with cooled boshes failed to make good malleable iron. We do not know whether the iron manufacturers in England will assent to the fol- lowing proposition laid down by the American metallurgist, v«. : " That the smaller the amount of coal consumed, or the lower the temperature of the hearth in the blast furnace, the better will be the quality of the metal ; that is, the more fit it will become for im- provement in the puddUng furnace. The advantage of heavy burden in the blast furnace, is not only that it reduces the first cost of the metal, but makes a far superior article for 664 IKON, subsequent operations. The worst cold short, or sulphurous metal, smelted by a low heat, is quite as good as the best metal from the best ore smelted by a high temperature." Whatever may be thought of the latter part of this quotation, no iron manufacturer will deny that careful attention to the blast furnace is the best security of success in the puddling furnace, and that success in the one is in proportion to the economy observed in relation to the other ; or that it is hopeless to attempt to improve in the puddling furnace pig iron made in a furnace that is constantly changing its burden and manage- ment ; such iron is most advantageously disposed of by being worked up into coarse bar or railroad iron. In the autumn of 18.56 the attention of ironmasters and of the public generally was powerfully excited by a jjroposal from Mr. Bessemer to manufacture iron and steel from crude iron, without any fuel at all. The views of Mr. Bessemer were first communicated to the public in a paper read by that gentleman at the meeting of the British Associa- tion held at Cheltenham in August. From this paper the following extracts are taken, descriptive of the apparatus employed, and of the phenomena attending the conversion: "The furnace is acylindrical vessel of three feet in height, somewhat like an ordinary cupola furnace, the interior of which is lined with fire-bricks; and at about two inches from the bottom are inserted fire tuyere pipes, the nozzles of which are formed of well- burnt fire clay, the orifice of each tuyere pipe being about three-eighths of an inch in di- ameter. These are so put into the brick lining (from the outer side) as to admit of their removal or renewal in a few minutes when they are worn out. At one side of the vessel, about half way up from the bottom, there is a hole made for running in the crude metal ; and on the opposite side a tap bole stopped with loam, by means of which the iron is run out at the end of the process. The vessel is placed so near tlie discharge hole of the blast furnace as to allow the iron to flow along a gutter into it. A small brass cylinder is required, capable of compressing air to about 8 lbs. or 10 lbs. to the square inch. A communication having been made between it and the tuyeres, the con- verting vessel is in a condition to commence work. Previous, however, to using the cupola for the first time, it must be well dried by lighting a fire in the interior. The tuyeres are situated nearly close to the bottom of the vessel ; the fluid metal rises, there- fore, some 18 inches or two feet above them. It is necessary, in order to prevent the metal from entering the tuyere holes, to turn on the blast before allowing the crude iron to run into the vessel from the blast furnace. This having been done, and the fluid iron run in, a rapid boiling up of the metal is heard going on within the vessel, the metal being tossed violently about, and dashed from side to side, shaking the vessel by the force with which it moves from the throat of the converting vessel. Flame will then im- mediately issue, accompanied by a few bright sparks. This state of things will continue for about 15 or 20 minutes, during which time the oxygen of the atmospheric air com- bines with the carbon contained in the iron, producing carbonic acid gas, and at the same time evolving a powerful heat. Now as this heat is generated in the interior of, and is diffused in innumerable fiery bubbles through, the whole fluid mass, the metal absorbs the greater part of it, and its temperature becomes immensely increased, and by the expiration of 15 or 20 minutes, the mechanically mixed carbon or graphite has been entirely consumed. The temperature is, however, so high that the chemically combined carbon now begins to separate from the metal, as is at once indicated by an immense increase in the volume of the flame rushing out at the throat of the vessel. The luetal now rises several inches above its natural level, and a light frosty sing makes its appear- ance, and is thrown out in large foam-like masses. This violent eruption of cinder generally lasts 5 or 6 minutes, replacing the shower of sparks and cinder which always accompanies the boil. "The rapid union of carbon and oxygen which thus takes place, adds still further to the temperature of the metal, while the diminished quantity of carbon present, allows a part of the oxygen to combine with the iron, which undergoes combustion, and is con- verted into oxide, at the excessive temperature that the metal has now acquired ; the oxide, as soon as it is formed, undergoes fusion, and forms a powerful solvent of those earthy bases that are associated with the iron. The violent ebullition which goes on mixes most intimately the scoriiE and metal, every part of which is brought into contact with the fluid, which will thus wash and cleanse the metal most thoroughly from the silica and other earthly bases, while the sulphur and other volatile matters which cling so tenaciously to iron at ordinary temperatures, are drawn oft', the sulphur combining with the oxygen and forming sulphurous acid gas. The loss in weight of crude iron during its conversion into an ingot of malleable iron was found on a mean of four ex- periments to be 12i per cent., to which will have to be added the loss of metal in the finishing rolls. This will make the entire loss probably not le.«s than 18 per cent., instead of about 28 per cent., which is the loss on the present system. A large portion of that metal is, however, recoverable, by treating with carbonaceous gases the rich ox- ides thrown out of the furnace during the boil. These slags are found to contain mOJ^". 665 innumerable small grains of metallic iron, which are mechanically held in suspension in the slags, and may be easily recovered by opening the tap hole of the converting vessel, and allowing the fluid malleable iron to flow into tlie iron ingot moulds placed there to receive them. " The masses of iron thus formed will be perfectly free from any admixture of cinder, oxide, or any other extraneous matters, and will be far more pure and in a sounder state of manufiicture than a pile formed of ordinary puddled bars. And thus it will be seen that by a siugle process, requiring no manipulation or particular skill, and with only one workman, from 3 to 5 tons of crude irou passes into the condition of several piles of malleable iron in from 30 to 35 minutes, with the expenditure of about ^ of the blast now- used in a finery furnace with an equal charge of iron, and with the consumption of no other fuel than is contained in the crude iron. . . . " One of the most important facts connected with this new system of manufacturing malleable iron, is that all the iron so prepared will be of that quality known as charcoal iron, because the whole of the processes being conducted without the use of mineral fuel, the iron will be free from those injurious properties which Jhat description of fuel never fails to impart to iron that is brought under its influence. " At that stage of the process immediately following the boil, the whole of the crude iron has passed into the condition of cast steel of ordinary quality. By the continuation of the process, the steel so produced gradually loses its small remaining portion of carbon, and passes successively from hard to soft steel, and from soft steel to steely iron, and eventually to very soft iron ; hence at a certain period of the process any quality of metal can be obtained." The phenomena attending this novel process of iron-making are very well described in the above extract; and if we substitute for the words "a few bright sparks," the words '■ showers of bright sparks, poured out in enormous quantities, projected thirty or forty feet into the air, and falling on all sides in a thick shower," a good idea may be formed of the gorgeous display of pyrotechny which is exhibited. We must demur, however, to the statement that " the sulphur and other volatile matters present in the crude iron are drawn off;" the fact being that the sulphur and phosphorus appear to have suffered little if any diminution, notwithstanding the exces.^ive temperature and tiie powerful oxidizing action to which the iron has been subjected. Thus Mr. Abel found, in a specimen of Mr. Bessemer's product, from O'-t to 0'5 per cent, of phosphorus, and from 0'05 to 00 per cent, of sul- phur ; the Blaenarvon pig, from which it was stated to have been prepared, containing O'S of the former and 0'06 of the latter ; and in a sample, broken off from an ingot cast at Baxter House, Sept. 1st, 1856, on which occasion we were present, and witnessed the whole process, we obtained 0'6 per cent, of phosphorus and 0'08 per cent, of sulphur ; similar results have been obtained by other chemists. The carbon and silicon, on the other hand, are eliminated, the latter wholly so, while the quantity of the former is reduced to a few hundredths per cent. ; we think also that Mr. Bessemer is mistaken in stating that the iron produced by his method contains " no admixture of oxide," for the specimens which we have had an opportunity of examining, presented unmistakable evidence of partial oxidation in the very centre of the ingot, nor do we see how it could well be otherwise. It will easily be imagined that a process which, if successful, must have revolutionized the whole iron manufacture, was speedily subjected to a most careful and sifting investiga- tion ; and, for some months after its announcement, the papers were filled with communica- tions from all parts of the country, detailing experiments made on the large scale to test its value ; the results, unfortunately for the ingenious projector, were unanimously unfavorable. We quote first from the " Mining Journal " of Xov. 29, 1856 : " The Dowlais Company appear to have thoroughly and impartially tested Mr. Besse- mer's process, and the results obtoined can only be regarded as a total failure A Bessemer furnace was erected, and acted excellently as far as the process was concerned, but failed to produce any thing like malleable iron. The iron used was from clay-ironstone, Whitehaven haematite, and small portions of forge cinders, in the proportions usually em- ployed in Wales for rails and merchant iron. After the metal had been subjected to a blast of 8 lbs. pressure, it w;is withdrawn and taken to the ' squeezer,' as is usual with puddled blooms, to take out the dross and unite the particles of metal. Instead of acting like pud- dled iron, Mr. Bessemer's bloom under the squeezer was a mere mass of red-hot friable matter, and, from its crumbling and non-cohesion, was with difficulty formed into an ingot : when pa.ssed through the rolls it broke on the drawing side as easily as very ' red short ' iron, to the infinite gratification of the men, who greeted each failure with hearty cheers. By mixing slag with the metal, a slight improvement was effected, but, on being submitted to a similar manipulation, it was found to be no better than ' cold short' iron." From the " Cambrian,' 10th Jan., 1857 : — " On December 31st the Briton Ferry Iron Company received two of Bessemer's finest ingots of iron to test its value after passing through the rolls. Notwithstanding every care that was bestowed on the process, it was found impossible to do any thing with it to the 666 IROI"!". purpose, and the manager informs us that old rckit iron, after passing through the same process, is worth by at least £3 per ton more than that tried on this occasion." At a meeting of the Polytechnic Society at Liverpool, Monday, Sept. 16, 1856, the chairman, Edward Jones Eyre, is rejiorted (" Daily News ") to have said that a specimen of Bessemer's iron had been received and tested l)y Jlr. Clay in the pi-escnce of Mr. Daw- ' son and himself, and, he regretted to say, had been far from satislactory ; the specimen submitted had all the appearance of burned and itnjierfevt cant-iron. He might say it was rotten hot and rotten cold. Mr. Dawson corroborated this statement, and also said that he had been much disappointed in the result ; the portion submitted to the rolling machine had proved in every way intractable. The chairman added, that he hoped ere long better results would be obtained ; but in the one to which he referred, he was informed that the cast-iron cost £6 per ton originally, and after being operated on, as he saw it, he did not consider it worth £4 per ton. Lastly, we find in the " Mining Journal " of January 3d, 1857, that the Bessemer pro- cess was tried at the works of Messrs. Jackson, near Glasgow. The usual appearances were noticed, and after about 10 nanutes the furnace was tapped, and the puiified iron ran wliite and limpid into moulds prepared for the purpose. Alter allowing it to cool, it was exam- ined ; it had a bright silvery whiteness with large crystals, but was exceedingly brittle. When rolled it preserved the same crystalline appearance on fracture, but in a state of greater compression and without the slightest trace of fibre. It is stated to have been deii- cient in every quality which would render it valuable for such [)urposes as malleable iron is usually applied to — in fact, the specimens examined were not malleable, and had nothing of tenacity or ductility, properties which render iron valuable, and are so iudispen.sable for the mechanical requirements of the present age. Although, therefore, it is scarcely probable that fibrous iron will ever be made from metal that has been subjected to Bessemer's treatment, and although that gentleman was premature in announcing his invention as a thing proved to be practical, we are far from asserting, as some have done, that the time of iron inasters has been needlessly occupied in experimenting on the subject, or that no good is likely to accrue to the iron manufacturer from all that has been done and written thereon. The extraordinary tenacity with which iron retains sulphur and phosphorus has been exhibited, and the fact that we must resort to other oxidizing agents than that of air to eliminate them has been demonstrated. The inju- rious effect of an excessive temperature on the body and quality of iron has been clearly manifested, and the opinions of those whose experience has taught them that it is vain to look for the production of a tough flexible bar from iron which has lost nearly the whole of its carbon, rapidly or without manipulation, has been confirmed. It is more than prob- able, that iron containing only 05 per cent, of carbon, has almost lost the property of be- coming fibrous by any treatment ; for without going so far as to assert that the develop- ment of fibre depends on the presence of carbon, or that carbon exercises a specific func- tion in bringing about this molecidar condition of the iron, analysis shows that the toughest and most flexible bar iron contains a far larger quantity of carbon than that above indicated, as will be seen by the following analyses by Gay-Lussac, "Willson, Karsten, and Bromeis. Amount of Carbon in Bar Iron. Carhon. Best bar iron from Sweden 0-293 " " 0-240 Bar iron from Crcusat 0-159 Bar iron from Champagne ----. 0-193 Bar iron from Berry - - - - -0-162 Cold aJwrt bar iron from Moselle 0-144 Soft bar iron analyzed by Karsten 0-200 Hard bar iron by Karsten 0-500 Three different varieties produced from white pig iron by the Swabian method of refining, analyzed by Bromeis ..--.--- 0-318 Three different varieties produced from white pig iron by the Swabian method of refining, analyzed by Bromeis 0-354 Three different varieties produced from white pig iron by the Swabian method of refining, analyzed by Bromeis - - 040 Three varieties produced from various kinds of pig iron by the Miigdesprung method of refining ----------- 0"324 Three varieties produced from various kinds of pig iron by the Miigdesprung method of refining . - - 0-497 Three varieties produced from various kinds of pig iron by the Miigdesprung method of refining 0-CG It will be noticed that the smallest amount of carbon indicated in these anal.vses is nearly three times greater than that found in Bessemerized iron, and in this specimen the IROX. 667 iron is stated to be " cold short," which means deficient in fibre ; it is probable that iron retains the last portion of carbon with extraordinary tenacity, and that it can only be made to yield it up by the action of excessive temperature and oxygen ; it then passes into a con- dition of what is called burnt iron, which Gmelin states (vol. v. p. 205, Englixh Transla- tion) is the only variety of bar iron that is free from carbon. This is clearly the condition of the ingots made by Bessemer's process ; it is stated, however, that by proper manage- ment any desired quantity of carbon may be retained, and it remains to be proved how fur this will be practicable on the large scale, and whether those varieties of steel and semi- steel alluded to in the patents can really be produced. Some interesting experiments on fused wrought iron have recently been made by Mr. Riley of the Dowlais Iron Works. By exposing fragments of block plate from the tin works for two hours to the highest heat of a wind furnace, the fragments being covered with cinder from an old assay, a perfectly fused button weighing 1,638 grains, was ob- tained. When cold, the mass was crystallized and easily broken, the fracture being in tlie direction of the planes of cleavage of the crystals ; one half of the button being worked out into a i inch bar was very soft, with a fine face, and sharp even edges like steel ; two pieces when welded, worked well at a welding heat, but on cooling to a red heat be- came cracky and broke. The fracture of the iron before it had been exposed to welding heat was silky and the body was very tough ; it could readily be bent back double without cracking. This experiment was repeated several times, with similar results, the fused but- tons being very tough and fibrous when cold, but invariably cracking and breaking to pieces after having been subjected to a welding heat. It would appear, therefore, that fused wrought iron is almost a worthless substance. Mr. Riley is engaged in further ex- periments, which, it is to be hoped, will throw some light on this singular property of fused wrought iron. Squeezers are machines which condense a ball by pressure. They are either single or . double ; their construction will be readily understood from %. 362 which represents a single level squeezer of the simplest construction ; the bed plate a is cast in one piece ; it is 6 feet long, 15 inches wide, and 12 inches high. The whole is screwed down on a solid foundation of stone, brick, or timber: b is the movable part, which makes from 80 to 90 motions per minute. The motion is imparted by the crank c, which in turn is driven by means of a strap and pulley by the elementary power. The diameter of the fly wheel is from 3 to 4 feet. The anvil d is about two feet in length, and from 12 to 14 inches in width ; it is a movable plate at least 3 inches thick, wiiich if injured can be replaced by another ; the face of the working part of the lever exactly fits the anvil, and consists of plates attached by means of screws. It is desirable to have all these face plates in small parts of 8 or 10 inches in width ; by this means they are secured against breaking by ex- pansion and contraction. The whole machine, including the crank and every thing, is mad6 of cast-iron, and weighs from 4 to 5 tons. According to Overman this machine is both clicap and durable, .ind will squeeze 100 tons of iron per week. Fiff. 363 represents the double squeezer, employed at many English iron works. The drawing is taken from a machine at the Dowlais Iron Works, figured in Mr. Trurau's work. Many other forms are in use. Mff. 364 represents Brown's patent bloom-squeezer. Tlie heated ball of puddled iron K, thrown on the top is gradually pressed between the revolving rollers as it descends, and at last emerges at the bottom, where it is t!n-own on to a movable " Jacob's ladder," by which it is elevated to the rolls. This machine effects a consiilcrable saving of time, will do the work of 12 or 14 furnaces, and may be constantly going as a feeder to one or two 668 ieo:n". pairs of rolls. There are two distinct forms of this machine ; in the one figured the bloom receives only two compressions ; in another, which is much more eflfective, it is squeezed 863 four times before it leaves the rolls and falls upon the Jacob's ladder. Another form of squeezer is shown infff 365. A table a a with a lodge rising up from it to a height of about 2 feet, so as to form an open box, is firmly imbedded in masonry ; within this is a revolving box, c, of similar char- acter, much smaller than the la?t, and placed eccentrically in regard to it. The ball or bloom I) is placed between the innermost revolving box c and the outer case a a where the space between them is greatest, and is carried round till it emerges at e, compressed and fit for the rolls. 365 3GG IRON. 669 The re-lieating furnace is shown in section injir/. 3fi6 ; it differs but little from a puddling furnace. The whole interior, with the exception of the hearth a, is made of fire-brick ; the hearth is made of sand. For this purpose a pure siliceous sand is required ; the coarser the better. The hearth slopes considerably towards the flue, the object of which is to keep the hearth dry and hard. Tiie iron wasted in re-heating combines with the silica of the sand, forming a very fusible cinder, which flows ott" through the opennig at h, at which there is a small flre to keep the cinder liquid. The thickness of the sand bottom is from 6 to 12 inches, resting on fire-brick : it generally requires re-making after two or three heats. Tiie height of the fire-brick arch, or its distance from the sand bottom, is from 8 to l"i inches. The area of the fire-place averages 12 feet, and the width of the furnace varies from 5 to 8 feet. When the piles are charged into the furnace, the door is shut, and fine coal is dusted around its edges to exclude the cold air ; the temperature is raised to the highest intensity as quickly as possible, and the workman turns the piles over from time to time that they may be brought to an uniform welding heat in the shortest possible time. It is thought by many that a purer iron is obtained by subjecting the balls as they come out of the puddling furnace to the action of the hammer at first, rather than to the roughing rollers, as by the latter process vitrified specks remain in the metal, which the hammer ex- pels. Hence in some works the balls are first worked under the forge hammer, and these stampings being afterwards heated in the form of pies or cakes, piled over each other, are passed through the roughing mills. Bars intended for boiler or tin plates are made from the best cold blast mine iron. The raw pig is refined in the usual manner with coke, the loss amounting to from 2^ to 3 cwls. per ton. It is then refined a second time with charcoal, the loss amounting again to from 2.V to 3 cwts. per ton. After this second refining it is beaten into flat plates white hot by the tilt hammer and thrown into cold water ; the sudden chilling makes it more easily broken into small slabs. The slabs are piled in heaps and welded in the hollow fire, coke being the fuel ; the slabs are laid across the fire, and do not come into contact with the fuel ; the blast is thrown under the fuel, and the heat is immense ; when the piles are nearly at the fusing point, they are withdrawn and passed under the rollers ; they are again heated in the hollow fire, then again rolled and heated a third time in the ordinary reverberatory furnace, after which they are drawn out into flat bars for boiler plates, or for tin plates: the loss in these operations amounts to from 3i to 4 cwts. per ton. About 9 heats are accom- plished in 12 hours, each heat consisting of 2^ cwts. of refined metal, and consuming 5 baskets of charcoal. The bars intended for tin plates are repeatedly heated and rolled until of the requisite thinness ; the plates are then cut into squares, and annealed by exposing them for several hours to heat in covered iron boxes, being allowed to cool very slowly ; this gives the plates the proper degree of pliancy. The next operation is that of pickling ; the plates are im- mersed in dilute sulphuric acid for the purpose of removing from their surfaces all oxide and dirt ; after remaining in the acid for the requisite time, they are thoroughly washed in successive troughs of water, and then dried in sawdust ; finally, the surfaces of the metal are prepared for the reception of the tin, by rubbing them with leather upon cushions of sheepskin. The spent sulphuric acid is run out into evaporating pans, and the sulphate of iron crystallized out. In order to tin the plates, they are immersed in a bath of melted tin, the surface of which is covered with tallow or palm oil ; when sufficiently covered, they are transferred to the briixhcr on the loft-hand side of the tinner ; he passes a rough brush rapidly over each side of the plate, wherc!)y the superfluous tin is removed ; he then plunges the plate again into the tin bath, and passes it on to his left-hand neighbor, who gives it a washing. The plate passes through several hands before it is dried. Great skill is required in the tinning process ; nevertheless in a well-conducted work the wasters do not amount to more than 10 per cent. ; a small percentage of which are so bad as to require to be re- worked. (Jreat care is taken to avoid waste, tin being worth 150/. per ton. A box of 22,5 sheets of tin plates, 10 inches by 14, consumes about 8i lbs. of tin. See Tin Plate. Drg assa>/ of iron ores. — The object of a drg assag of an iron ore is to ascertain by an experiment on a small scale the amount of iron which the ore should yield when smelted on the large scale in the blast furnace. For this purpose, the metal must be deoxidized, and such a temperature produced as to melt the metal and the earths as.sociated with it in the ore, so that the former may be obtained in a dense button at the bottom of the crucible, and the latter in a lighter glass or slag above it. Such a temperature can only be obtained in a wind furnace connected with a chimney at least 30 feet in height, and when made expressly for assaying the furnace, is generally built of such a size that four as.says may be made at the same time, viz. about 14 inches sciuaro, anil 2 feet in depth from the unby the volumetric method of Marguerite, or by that of Dr. Penny : both give very exact results. Marguerite's method is based on the reciprocal action of the salts of protoxide of iron and permanganate of potash, whereby a quantity of the latter is decomposed exactly proportionate to the quantity of iron. The ore (about 10 or 15 grains) is dissolved in hydro- chloric acid, and the metal brought to the minimum of oxidation by treating the solution with suljjhite of soda, (or better, sulphite of ammonia,) and boiling to expel the excess of sulphurous acid ; the solution of permanganate of potash is then cautiously added drop by drop, until the pink color appears, and the number of divisions of the burette required for the purpose accurately noted. The solution should be considerably diluted, and there must be a sufficient quantity of free acid present to keep in solution the peroxide of iron formed and also the oxide of manganese. The whole of the iron must be at the minimum of oxidation, and the excess of sulphurous acid must be completely expelled ; if the latter precaution be neglected, an erroneous result will be obtained, as the sulphurous acid will itself take oxygen from the permanganic acid, and thus react in the same manner as iron. To prepare the permanganate of potash, 7 parts of chlorate of potassas, 10 parts of hydrate of potassa, and 8 parts of peroxide of manganese are intimately mixed. The manganese must be in the finest possible powder, and the potash having been dissolved in water, is mixed with the other substances, dried, and the whole heated to very dull redness for an hour. The fused mass is digested with water, so as to obtain as concentrated a solu- tion as possible, and dilute nitric acid added till the color becomes of a beautiful violet ; it is afterwards filtered through asbestos. The solution must be defended from the contact of organic matter, and kept in a glass stoppered bottle. If the solution be evaporated, it yields beautiful red acicular crystals : it is better to employ the crystals in the preparation of the test liquor, as the solution keeps much better when no manganatc is present. To prepare the normal or test liquor, a certain quantity, say 15 grains, of piano-forte wire is dissolved in pure hydrochloric acid ; after the disengagement of hydrogen has ceased, and the solution is complete, the liquor is diluted with about a pint of water, and accurately divided by measurement into two cfjual parts, the number of burette divisions of the solu- tion of permanganate required to produce in each the pink color is accurately noted ; and this number is then employed to reduce into weight the result of the analysis of an ore. A useful normal liquor is made by dissolving 100 grains of the crystallized permanganate in 10,000 grains of water. Penny's method is based on the reciprocal action of chromic acid and protoxide of iron, whereby a transference of oxygen takes place, the protoxide of iron becoming converted into peroxide, and the chromic acid into sesquioxide of chromium. The process is con- ducted as follows : A convenient quantity of the specimen is reduced to coarse powder, and one-half at least of this is still further pulverized until it is no longer gritty between the fingers. The test solution of bichromate of potash is next prepared : 44 4 grains of this IKON. 673 salt in fine powder are weighed out, and put into a burette graduated into 100 equal parta, and warm distilled water is afterwards poured in until the instrument is filled to 0. The palm of the hand is then securel_y placed on the top, and the contents agitated by repeatedly inverting the instrument until the salt is dissolved and the solution rendered of uniform density throughout. Each division of the solution thus prepared contains 0'4-44 grains of bichromate, which Dr. Penny ascertained to correspond to half a grain of metallic iron. The bichromate must be pure, and should be thoroughly dried by being heated to incipient fusion. 100 grains of the pulverized iron-stone are now introduced into a Florence tiask with H oz. by measure of strong hydrochloric acid and i oz. of distilled water. Heat is cautiously applied, and the mixture occasionally agitated until the effervescence caused by the escape of carbonic acid ceases ; the heat is then increased, and the mixture made to boil, and kept at moderate ebullition for ten minutes or a quarter of an hour. About 6 oz. of water are next added and mixed with the contents of the flask, and the whole filtered into an evaporating basin. The flask is rinsed several times with water, to remove all adhering sohition, and the residue on the filter is well washed. Several small portions of a weak solution of red prussiate of potash (containing 1 part of salt to 40 water) are now dropped upon a white porcelain slab, which is conveniently placed for testing the solution in the basin during the next operation. The prepared solution of bichromate of potash in the burette is then added very cautiously to the solution of iron, which must be repeatedly stirred, and as soon as it assumes a dark greenish shade it should be occasionally tested with the red prussiate of potash. This may be easily done by taking out a small quantity on the end of a glass rod, and mixing it with a drop of the solution on the porcelain slab. When it is noticed that the last drop communicates a distinct blue tinge, the operation is terminated ; the bui-ette is allowed to drain for a few minutes, and the number of divisions of the test liquor consumed read off. This number multiplied by 2 gives the amount of iron per cent. The necessary calculation for ascertaining the corresponding quantity of protoxide is obvious. If the specimen should contain iron in the form of peroxide, the hydrochloric solution is deoxidized as before by sulphite of ammonia. The presence of peroxide of iron in an ore is easily detected by dissolving 30 or 40 grains in hydrochloric acid, diluting with water, and testing a portion of the solution with sii/phoci/anide of potaa- siinn. If a decided blood-red color is produced, peroxide of iron is present. If it be desired to ascertain the relative proportions of peroxide and i)rotoxide of iron in an ore, two operations must be performed : one on a quantity of the ore that has been dissolved in hydrochloric acid in a stout stoppered bottle ; and another on a second quantity that has been dissolved as usual, and then deoxidized by sulphite of ammonia or of metallic zinc. It is advisable to employ the solution of bichromate much weaker than proposed by Dr. Penny, and to employ a burette graduated to cubic millimetres. A good strength is 1 grain of metallic iron =: 10 cubic centimetres of bichromate. Metals prccipitahle by sidphurcttcd Iii/drogenfrom tlie hydrochloric solution. — A weighed portion of the ore varying from 200 to 2,000 grains is digested for a considerable time in hydrochloric acid ; the solution is filtered off; the iron in the filtrate reduced when necessary by sulphite of ammonia, and a current of sulphuretted hydrogen passed through it. A small quantity of sulphur which is always suspended is collected on a filter and thoroughly washed; it is then incinerated at as low a temperature as possible. Tlie residue (if any) is mixed with carbonate of soda and heated upon charcoal before tlie blowpipe ; any globules of metal that may be obtained are dissolved and tested. Analysis of pig iron. — The most important constituents to be determined am car- bon, (combined and uncombiued,) silicon, sulphur, phosphorus ; those of less consequence, or of more rare occurrence, are manganese, arsenic, copper, zinc, chromium, titanium, cobalt, nickel, tin, aluminium, calcium, magneslion, and the metals of the alkalies. 1. Determination of the total ainount of carbon. — About 100 grains of the iron in small pieces are digested, at a moderate temperature, in C-oz. measures of a solution formed by dissolving 6 oz. of crystallized sulphate of copper, and 4 oz. of common salt in 20 oz. of water and 2 oz. of concentrated hydrochloric acid. Tlie action is allowed to proceed until all, or nearly all the iron is dissolved. Carbon and copper are left insoluble ; these are collected on a filter, and washed first with dilute hydrochloric acid, (to prevent the precipitation of subchloride of copper,) then with water, then with dilute caustic potash, and finally with boiling water. The mixed carbon and copper are dried on the filter, from which they are easily removed by a knife-blade, and are mixed with oxide of cop- per, and burned in a combustion tube in the usual way, with a current of air, or, still better, of oxygen. The carbonic acid is collected in Liebig's apparatus, from which the amount of carl)on is calculated. 2. Graphite, or uncombined carbon. — A weighed portion of the finely divided iron (filings or borings may be used) is digested with moderately strong hydrochloric acid ; the combined carbon is evolved in combination with hydrogen, while the graphite is left undissolved. It is collected on a filter, washed, and then boiled wiih a solution of caustic potash, sp. gr. \-21, in a silver dish ; the silica which existed in the iron in the form of Vol. III.— 43 674 IRON. silicon is hereby dissolved; the clear caustic solution is drawn off by a pipe or syphon, and the black residue repeatedly washed ; it is dried at as high a temperature as it will bear, and weighed ; it is then heated to redness in a current of air, until the whole of the carbon is burnt off. A reddish residue generally remains, which is weighed, and the weight deducted from that of original black residue ; the difference gives the amount of graphite. 3. Silicon. — The amount of this element is determined by evaporating to dryness a hydrochloric solution of a weighed quantity of the metiil : the dry residue is redigested with hydrochloric acid, diluted with water, boiled and filtered ; the insoluble matter on the filter is washed, dried, and ignited, until the whole of the carbon is boiled off; it is then weighed, after which it is digested with solution of potash, and the residue, if any, washed, dried, ignited, and weighed : the difference between the two weights gives the amount of silicic acid, 100 parts of which indicate 47 parts of silicon. PhosphoriLx. — A weighed portion of the metal is digested in nitro-hydrochloric acid, evaporated to dryness, and the residue redigested with hydrochloric acid. The solution is treated precisely as recommended for the determination of phosphoric acid in ores ; every 100 parts of pyrophosphate of magnesia indicate '28'50 parts of phosphorus. Sulphur. — In gray iron tliis element is very conveniently and accurately estimated by allowing the gas evolved by the action of hydrochloric acid on a weighed quantity (about 100 grains) of the metal, in filings or borings, to pass slowly througli a solution of acetate of lead acidified by acetic acid : the sulphur, the whole of which takes the form of sul- phuretted hydrogen, enters into combination with the lead, forming a black precipitate of sulphide of lead, which is collected, washed, and converted into sulphate of lead by digesting it with nitric acid, evaporating to dryness, and gently igniting: iOO parts sul- phate of lead r= 10-5.5 sulphur. The most minute quantity of sul])liur in iron is detected by this process. If, however, crude while iron is under examination, this method does not give satisfactory results, on account of the difficulty with which it is acted upon by hydrochloric acid; it is better, therefore, to treat the metal with nitro-hydrochloric acid, evaporated to dryness, redigest with hydrochloric acid, and then precipitate the filtered solution with great excess of chloride of barium ; or the finely divided metal may be fused in a gold crucible with an equal weight of pure iiitrate of soda and twice its weigiit of pure alkaline carbonates ; the fused mass is extracted with water acidified with hydro- chloric acid, and finely precipitated by chloride of barium. Manffanese. — This metal is determined by the process described for its estimation in ores ; the iron must exist in the solution in the form of sesquioxide. Arsenic and copper. — The nitro-hydrochloric solution of the metal is evaporated to dryness, redigested with hydrochloric acid, and filtered. The iron in the clear solution is reduced to protochloride by boiling with a sufficient quantity of sulphite of ammonia, the solution is boiled till it has lost all smell of sulphurous acid. It is then saturated with sulphuretted hydrogen, and allowed to stand for 24 hours in a closed vessel, the excess of gas is boiled off, and the precipitate, if any, collected on a small filter and well washed ; it is digested with monosulphide of potassium, which dissolves th.e sulpliide of arsenic, leaving the sulphide of copper untouched; the latter is decomposed by heating with nitric acid, and the presence of copper evinced by the addition of ammonia, which produces a fine blue color; the sulphide of arsenic is precipitated from its solution in sulphide of potassium by dilute sulphuric acid; it may be redissolvcd in arp(a regia, and the nitric acid having been expelled by evaporation, the arsenic may be reduced in Marsh's apparatus. Nickel and cobalt.-~-The?e metals, if present, will be found in the solution from which the copper and arsenic have been precipitated by sulphuretted hydrogen. The solution is peroxidized, and the sesquioxide of iron precipitated by slight excess of carbonate of baryta, after which the nickel and cobalt are precipitated by sulphide of ammonium. Chromium and vanadium. — These metals, which should be looked for in the car- bonaceous residue obtained by dissolving a large quantity of the iron in dilute hydro- chloric or sulphuric acid, are detected as follows ( \Vi:hler) : — Tlie ignited residue is inti- mately mixed with one-tliird of its weight of nitre, and exposed for an hour in a crucil)Ie to a gentle ignition. When cool, the mass is powdered and boiled with water. The filtered solution is gradually mixed and well stirred with nitric acid, taking care that it may still remain slightly alkaline, and that no nitrous acid is liberated which would reduce the vanadic and chromic acids. The solution is then mixed with an excess of solution of chloride of barium as long as any precipitate is produced. The precipitate, which consists of vanadiate and chromate of baryta, is decomposed with slight excess of dilute sulphuric acid, and filtered. The filtrate is ncutnilized with ammonia, concentrated by evaporation, and a fragment of chloride of ammonium placed in it. In proportion as the solution becomes saturated with chloride of ammonium, vanadate of ammonia is deposited as a white or yeUow crystalline powder. To test for chromium only, the mass after fusion with nitre is extracted with water, and then boiled with carbonate of IVORY, FICTILE. 675 ammonia ; the solution is neutralized with acetic acid, and then acetate of lead added ; the production of a yellow precipitate indicates c/iromic acid. Aluminium. — This metal is best separated from iron by first reducinjf the latter to the state of protoxide by sulphite of ammonia, then neutralizing with carbonate of soda, and afterwards boiling with excess of caustic potash until the precipitate is black and pulverulent. The solution is then filtered off, slightly acidulated with hydrochloric acid, and the alumina precipitated by sulphide of ammonium. Calcium and magnesium. — These metals are found in the solution from which tlie iron and aluminium have been separated ; they both exist probably (together with the aluminium) in the cast iron in the form of slag, and are best detected in the black residue which is left on dissolving the iron in dilute sulphuric or hydrochloric acid. After digesting this residue with caustic potash, and burning away the graphite, a small quantity of a red powder is left, which is composed of sUicic acid, oxide of iron, alumina, lime, and magnesia; if 500 grains of cast iron are operated upon, a sufficient quantity of insoluble residue will be obtained for a quantitative determination of its constituents. — H. M. N. IVORY. It is not our intention to enter into the consideration of the handicrafts em- ploying ivory, but a short account of the methods of preparing this beautiful material, which we extract from HoltzapfePs Mechanical Manipulations, will be of value. " On account of the great value of ivory, it requires considerable judgment to be em- ployed in its preparation, from three conditions observable in the form of the tusk ; fii-st, its being curved in the direction of its length ; secondly, hollow for about half that extent, and gradually taper from the solid state to the thin feather edge at the root ; and thirdly, elliptical or irregular in section. These three peculiarities give rise to as many separate considerations in cutting up the tooth with the requisite economy, as the only waste should be that arising from the passage of the thin blade of the saw : even the outside strips of the rind, called spills, are employed for the handles of penknives, and many other little objects ; the scraps are burned in retorts for the manufiicture of ivory black, employed for making ink for copperplate printers, and other uses ; and the clean sawdust and shavings are sometimes used for making jelly. " The methods of dividing the tooth, either into rectangular pieces or those of a circular figure required for turning, are alike in their early stages, until the lathe is resorted to. The ivory saw is stretched in a steel frame to keep it very tense ; the blade generally meas- ures from fifteen to thirty inches long, from one and a half to three inches wide, and about the fortieth of an inch thick ; the teeth are rather coarse, namely, about five or six to the inch, and they are sloped a little forward, that is, between the angle of the coiumon hand- saw tooth and the cross-cut saw. The instrument should be very sharp, and but slightly set ; it requires to be guided very correctly in entering, and with no more ])ressure than the weight of its own frame, and is commonly lubricated with a little lard, tallow, or other solid fat. " The cutter begins generally at the hollow, and having fixed that extremity parallel with the vice, with the curvature upwards, he saws off that piece which is too thin for his purpose, and then two or three parallel pieces to the lengths of some particular works, for which the thickness of the tooth at that part is the most suitable ; he will then saw off one very wedge-form piece, and afterwards two or three more parallel blocks. " In setting out the length of every section, he is guided by the gradually increasing thickness of the tooth ; having before him the patterns or images of his various works, he will in all cases employ the hollow for the thickest work it will make. As the tooth ap- proaches the solid form, the consideration upon this score gradually ceases, and then the blocks are cut off to any required measure, with only a general reference to the distribution of the heel, or the excess arising from the curved nature of the tooth, the cuts being in general directed as nearly as may be to the imaginary centre of curvature. The greater waste occurs in cutting up very long pieces, owing to the dilference between the straight line and the curve of the tooth, on which account the blocks are rarely cut more than five or six inches long, ujiless for some specific object." IVORY, FICTILE, is plaster of Paris which has been made to absorb, after drying, melted spermaceti, by capillary action, or it luay be prepared according to Mr. Franchi's process as follows : Plaster and coloring matter are employed in the proportions of a pound of superfine plaster of Paris to half an ounce of Italian yellow ochre. They are intimately mixed by passing them through a fine silk sieve, and a plaster cast is made in the usual way. It is first allowed to dry in the open air, and is then carefully heated in an oven ; the plaster cast, when thoroughly dry, is soaked for a quarter of an hour in a bath containing equal parts of white wax, spermaceti, and stearine, heated just a little lieyond the melting point. The cast on removal is set on edge, that the supertluons composition may drain off, and before it cools, the surface is brushed, with a brush like that known by house painters as a sa-sh tool, to remove any wax which may have settled in the crevices; and finally when the plaster is quite cold, its surfiicc is polished by rubbing it with a tuft of cotton wool. 676 JAPANNING. JAPANNING is a kind of varnishing or lacquering, practised with excellence by the Japanese, whence the name. The only difference between varnishing and japanning is that after the application of every coat of color or varnish, the object so varnished is placed in an oven or stove at as high a temperature as can safely be employed without injuring the articles or causing the vainish to blister or run. For black japanned works, the ground is first prepared with a coating of black, made by mixing dross ivory black to a proper consistence with dark-colored anime varnish, as this gives a blacker surface than could be produced by japan alone. If the surface is re- quired to be polished, five or six coats of japan are necessary to give sufficient body to pre- vent the japan from being rubbed through in polishing. Colored japans are made by mixing with some hard varnishes the required color, and proceeding as described. See Varnish, vol. ii. JET. (Jaiet, ovjais, Fr.) Jet occurs in the upper lias shale in the neighborhood of Whitby, in Yorkshire, in which locality this very beautiful substance has been worked for many hundred years. The jet miner searches with great care the slaty rocks, and finding the jet spread out, often in extreme thinness between the laminations of the rock, he fol- lows it with great care, and frequently he is rewarded by its thickening out to two or three inches. The best jet is obtained from a lower bed of the upper lias formations. This bed has an average thickness of about 20 feet, and is known as jet rock. An inferior kind, known as soft jet, is obtained from the upper part of the upper lias, and from the sandstone and shale above it. The production of jet in this country appears to be limited to the coast of York- shire, from about nine miles south of Whitby to Boulby, about the same distance to the north ; the estates of Lord Mulgrave being especially productive. There is a curious allusion tothis in Drayton's Polyolbion : — The rocks by Moultarave, too, my glories forth to set, Out of their" crannied rocks can give you perfect jet. Dr. Young, in his Geology of the Yorkshire Coast, writes : — " Jet, which occurs here in considerable quantities in the aluminous Vjed, may be properly classed with fossil wood, as it appears to be vood in a high state of bitumerdzation. Pieces of wood impregnated with silex are, often found completely crusted with a coat of jet about an inch thick. But the most common form in which the jet occurs is in compact masses of from half an inch to two inches thick, from three to eighteen inches broad, and of ten or twelve feet long. The outer surface is always marked with longitudinal striae, like the grain of wood, and the transverse fracture, which is conchoidal, and has a resinous lustre, displays the annual growth in compressed elliptical zones. Many have supposed this substance to be indurated petroleum^ or animal pitch ; but the facts now quoted are sufficient to prove its ligneous origin." It does not appear to us that the " ligneous origin " of jet is by any means established ; indeed we think the amount of evidence is against it. There is no example, as far as we can learn, of any discovery of true jet having a strictly ligneous structure, or showing any thing like the conversion of wood into this coal-like substance. There appears, however, to have been some confusion in the observations of those who have written on the subject. Mr. Simpson, the intelligent curator of the Whitliy museum, who has paid much attention to the subject, says: — "Jet is generally considered to have been wood, and in many cases it undoubtedly has been so ; for the woody structure often remains, and it is not unlikely that comminuted vegetable matter may have been changed into jet. But it is evident that vege- table matter is not an essential part of jet, for we frequently find that bone, and the scales of fishes also have been changed into jet. In the Whitby museum there is a large mass of bone, which has the exterior converted into jet for about a quarter of an inch in thickness. Tlie jetty matter appears to have first entered the pores of the bone, and there to have hardened ; and during the mineralizing process, the whole bony matter has been gradually displaced, and its place occupied by jet, so as to preserve its original form." After an attentive examination of this specimen, we are not disposed to agree entirely with Mr. Simpson. Jet certainly incrusts a mass which has something the structure of a bone, but, without a chemical examination of its constituents, we should hesitate even to say it was bone. Wood without doubt has been found encrusted with jet, as fragments of animal matter may also have been. But it is quite inconsistent with our knowledge of physical and chemical changes, to suppose that both animal and vegetable matter would undergo this change. By process of substitution, we know that silica will take the place occupied by carbon, or woody matter ; as, for example, in the fossil palms of Trinidad, and the sihcified forests of KATTIMUXDOO oe CUTTEMUXDOO. 677 Egypt ; but we have no example within the entire range of the coal formations of the world of carbon taking the place of any of the earths. Jet is found in plates, which are sometimes penetrated by belemnites. Mr. Ripley, of Whitby, has several curious examples : two plates of jet, in one case enclose water-worn quartz pebbles ; and in another jet partially invests an angular fragment of quartz rock. '* This is the more remarkable," says Mr. Simpson, " as quartz rock, or, indeed, any other sort of rocky fragment, is rarely found in the upper lias." The very fact that we find jet sun-ounding belemnites, casing adventitious masses of stone, and investing wood, seems to show that a liquid, or at all events a plastic condition, must at one time have prevailed. We have existing evidence of this. Dr. Young, in the work already quoted, says : — " In the cavities of nodules containing petrifactions, we some- times meet with petroleum, or mineral oil. When first exposed, it is generally quite fluid, and of a dark green color ; but it soon becomes viscid and black, and at last hardens into a kind of pitch, which generally melts with heat, and when ignited burns with a crackling noise, and emits a strong bituminous smell." One more sample of evidence in favor of the view that jet has been formed from wood. It is stated (JReed's Illustrated Guide to \M)itbi/) that in front of the cliflwork of Haiburne Wyke existed a petrified stump of a tree, in an erect posture, three feet high, and fifteen inches across, having the roots of coaly jet in a bed of shale ; whilst the trunk in the sandstone was partly petrified, and partly of decayed sooty wood. Even in this example it would appear that, after all, a coating of jet was all that really existed upon this example of the equisetum, which probably stands where it grew. Mr. Simpson, in a valuable little publication, " Tlie Fossils of the Yorkshire Lias described frora Xature,icith a short Outline of the Geology of the Yorkshire Coast ,''' says : — " From all we know respecting this beautiful mineral, it appears exceedingly probable that it has its origin in a certain bituminous matter, or petroleum, which abundantly impregnates the jet-rock ; giving out a strong odor when it is exposed to the air. It is frequently found in a liquid state in the chambers of ammonites and belemnites and other cavities, and, whilst the unsuspicious operator is breaking a lias nodule, it flies out and stains his garment. This petroleum, or mineral oil, also occurs in nodules which contain no organic remains ; and I have been informed by an experienced jet miner that such nodules are often associated with a good seam of jet, and are therefore regarded as an omen of success." Jet is supposed to have been worked in this country long before the time of the Danes in England, for the Romans certainly used jet for ornamental purposes. Lionel Charlton, in the history of Whitby, says that he found the ear-ring of a lady, having the form of a heart, with a hole in the upper end for suspension from the ear; it was found in one of the Roman tumuli, lying close to the jaw bone. There exists no doubt that when the abbey of Whitby was the seat of learning and the resort of pilgrims, jet rosaries and crosses were common. The manufacture was carried on till the time of Elizabeth, when it seems to have ceased suddenly, and was not resumed till the year 1800, when Robert Jeflfei-son, a painter, and John Carter made beads and crosses with files and knives — a neck -guard, made in this manner, fetched one guinea. A stranger coming to Whitby saw them working in this rude way, and advised them to try to turn it ; they followed his advice and found it answer ; several more then joined them, and the trade has been gradually increasing since. Most of the best jet ornaments are sent to London, the inferior ones are mostly purchased for the American market. The jet workers complain of the great scarcity of designs in jet. Several designs have been sent them, but the artists not being acquainted with the peculiarities of the material, their designs are not generally applicable, and the manufacturer is much more successful in the imitation of natural objects than any artificial combination. KALEIDOPFTOX. An instrument devised by Prof. Wheatstone. An elastic thin bar is fixed by one of its extremities, and at its free end it carries a silvered or polished ball ; a ray of light is reflected from this ball, and when the thin plate is put in vibration, the fine point of light describes various curves, corresponding with the musical notes produced by the vibrations. KAKX. A Cornish miner's term, frequently, according to Borlase, used to signify the solid rock ; more commonly a pile of rocks. KARSTEN'ITE. The name given bv Haus to anhvdrous suli)hate of lime. KATTIMUXDOO or CUTTEMUXDOO. A caoutchouc-like substance obtained from the Euphorbia antiquorum of Roxburgh. It was first exhibited in this country in the Great Exhibition of 1851, being sent by Mr. W. Elliott from Vizagapatam. It was of a dark brown color, opaque except in thin pieces, hard and somewhat brittle at common temperatures, but easily softened by heat. Perfectly insoluble in boiling water, but becoming soft, viscid, and remarkably sticky and adhesive like bird-lime, reassuming, as it cools, its original character. 678 KEG. KEG. A cask containing five gallons. KEEVE, a milling term. A large vat used in dressing ores : also a breiccr^s term for a ma^sh tub. KEIR. A boiler used in I)leac'hing establishments. See Bleaching. KNIFE-CLEANING MACHINES. Mr. Kent's machine for this purpose consists of a box or case, containing a couple of wooden discs, fixed near to each other upon a hori- zontal iron rod or spindle, which passes through the case, and is caused to rotate by means of a winch-handle. Each disc is, for about three-fourths of the area of its inner face, cov- ered with alternate rows of bristles and strips of leather ; and the remaining fourth part is coveied with bristles only. The knife-blades to be cleaned are introduced through the openings in the case, between the rubbing surfaces of the discs ; and rotatory motion being given to the discs by a winch-handle, the knives are rapidly cleaned and polished. Mr. Masters constiucted knife-cleaning machines upon the same plan as the above ; but the rubbing surface of each disc is formed of strips of buff leather, with only a narrow circle of bristles around the edge of each surface, to clean the shoulders of the knives ; small brushes are fixed beneath the holes in the case, through which the blades of the knives are inserted, to prevent the exit of dust from the apparatus. Mr. Price has also devised a machine for cleaning knives, and another for cleaning forks. The knife-cleaner consists of a horizontal drum, covered with pieces of leather or felt, and fixed within another drum or circular framing, lined with leather or felt. The knives are introduced through openings in a movable circular yjlate, at the front of the outer casing, and enter between the surfaces of the two drums. The jilatc is fixed upon a horizontal axis, which extends through the case, and is furnished at the back with a handle ; by turning which the disc is caused to rotate and carry round the knives between the surfaces of the drums. The fork-cleaner consists of a box, with a long rectangular opening in the side ; behind which two biushes are fixed, face to face. Between these brushes the prongs of the forks are introduced, and the handles are secured in a carrier, which is made to advance and recede alternately by means of a throw-crank, and thereby thrust the prongs into and draw them out of contact with the brushes. The carrier consists of two metal plates, the lower one carrying a cushion of vulcanized india-rubber for the fork handles to rest upon, and the upper being lined with leather; they are hinged together at one end, and are coiniected at the other, when the handles have been placed between them, by a thumb- screw. KUEOSOTE, or CREOSOTE. One of the many singular bodies discovered by Reichen- l)ach in wood tar. It derives its name from XP^°-^ ^^^ fci^cc, I preserve, in allusion to its remarkable antiseptic properties. A great deal of confusion exists in the published ac- counts of wood creosote, owing to the variable nature of the results obtained by the chemists who have examined it. This confusion is not found with that from coal, which undoubtedly contains two homologous bodies, C'-IFO^ and C'^IFO" ; the first being car- bolic, and the second. cresylic acid. The composition of carbolic acid has long been known, owing to the researches of Laurent: cresylic acid was recently discovered by Williamson and Fairlie. Commercial coal creosote sometimes consists almost entirely of cresylic acid. Coal oils, of very high boiling point, contain acids ap])arently homologues of carbolic acid, higher up in the series than even cresylic acid, and yet perfectly soluble in potash. — {Gre- ville Witliiiinx.) There is little douljt that wood creosote consists essentially of the same substances as that from coal. The great difference in the odor arises chiefly from the fact of the product from coal retaining with oljstinacy traces of najihthaline, parvoline, and chinoline, all of which are extremely odorous. No creosote found in commerce is ever perfectly homogeneous, nor, in fact, is it necessary that it should be so. If perfectly solu- ble in pota.sh and acetic acid of the density ru70, and if it does not become colored by exposure to the air, it may be consi- f- . ^a S If, therefore, we admit aldehyde to be formed on the hydrogen type, that is to say, two atoms of hydrogen in which one is replaced bv the oxidized radical acetvl, we shall have for aldehyde, rr [ ; and for the lampates, acetylurets, or aldehydates, mi* ^' ^^''' hardt, who views the lampates in the above light, regards aldehyde as the true acetylous acid. See Acetyl. — C. G. W. LAPS. Metal polLshing wheels. Metal wheels or laps made of nearly every metal and alloy in common use, have been more or less employed in the mechanical arts as vehicles for the application of several of the polishing powders. But of all laps, notwithstanding their variety, those of lead, slightly alloyed, and supplied with powdcrecl emery, render the most conspicuous service. Generally the plane, or flat surface of the lap, is employed ; at other times the cylindrical edge, as by cutlers; but the portion actually used is in either case called the face of the lap. There are several kinds of laps. The lap is in some cases a thin disc of metal, fixed l)y means of a screwed nut against a shoulder on the spindle, but it is better with lead laps to employ an iron plate cast full of holes, to support the softer metal. The casting mimld may in this case be either an iron disc, with a central screw to fix the iron centre plate at the time of pouring, or the mould maybe made of sand, and in halves, after the usual manner of the foundry. In either case the iron plate should be made as hot as the fluid metal, which, by ent(>ring the holes, becomes firndy united to the iion, especially if the holes are largest on the reverse side, or that away from the lead. — Jlolt- zapffel. Lap is also a roll or sliver of cotton for feeding the cards of a spinning machine. LEAD. Although lead foruis an essential element in a large number of minerals, the ores of this metal are, strictly speaking, far from numerous. Of these the most important 684 LEAD. is sulphide of lead, or galena. This mineral, which possesses a metallic brilliancy, and has a lighter color than metallic lead, presents, in its cleavage, all the variations from large facettes and lamin;c indicating a cubic crystallization to a most minutely granular structure. It is extremely brittle, and its powder presents a brilliant blackish-gray appearance. The specific gravity of galena is 7'5 to IS, and its composition, when absolutely pure, is: — Lead 86-55 Sulphur 13-45 100-00 Galena is, however, but seldom found chemically pure, as, in addition to variable quan- tities of earthy imi)urities, it almost always contains a certain amount of silver. It is usually observed that galena presenting large facettes is less argentiferous than those varieties hav- ing a closer grain, and that finely granular steely specimens generally afford the largest amount.of silver. It would appear, from recent experiments, that the silver contained in the finely-granu- lar varieties of galena often occurs in the form of sulphide of silver, mechanically inter- mixed, whilst in the more flaky descriptions of this ore, the sulphides of lead and silver are chemically combined. Galena occurs in beds and veins, in granite, gneiss, day-slate, limestone, and sandstone rocks. In Spain it is found in the granite hills of Lanaies and elsewhere ; at Freiberg in Saxony it occupies veins in gneiss; in the Ilarz, Bohemia, Cornwall, and many other localities, it is found in killas, or clay-slate. The rich deposits of Derbyshire, Cumberland, and the north- ern di>tricts of England, are in the mountain limestone, whilst at Commcrn, near Aix-la- Chaj)olle, large ciuuntities of this ore are found disiseminatcd in the Bunter sandstone. This mineral is frequently associated with blende, iron and copper pyrites, the carbonate and other ores of lead, and usually occurs in a gangiie of sulphate of baryta, calcspar, spa- fhose iron, or quartz. It is also not unfrequently associated with fluorspar. The next most important ore of lead is the carbonate, which is a brittle mineral, of a white or grayish-white color, having a specific gravity varying from 6-46 to 6-50. Its com- position is: — Carbonic acid 16-05 Oxide of lead 83-56 99-61 Large quantities of this substance occur in the mines of the Mississippi Valley in the United States of America, where they were formerly thrown away as useless, but have since been collected and smelted. Vast deposits of this su1)stance have also been found in the Bunter sandstone, near Duren, in Prussia, and at P'rcyung, in Bavaria. In the two latter localities it appears to form the cement holding together the granules of quartz, of which the sandstone principally consists. These ores, which yield from 14 to 20 per cent, of metal, do not readily admit of being concentrated by wa.shing. The sulphate of lead does not often occur in sufficient (juantities to be employed as an ore of that metal. In appearance it is not unlike the carbonate, but may readily be distin- guished from it by its not dissolving with effervescence in nitric acid. Its specific gravity is from 6-25 to 6-30, and its composition: — Sulphuric acid 25-65 Oxide of lead 74-05 99-70 This ore of lead usually results from the oxidation of galena. At St. Martin's, near the Vega de Ribaddeo, in Spain, this mineral, more or less mixed with the phosphate of lead, is foimd in suflficient quantities to be made, on a small scale, the subject of an especial metallurgic treatment. Large f|uantities of sulphate of lead ores are also annually in)i)()rtcd into this country from the mines in Australia. These ores contain on an average 35 per cent, of lead, and 35 oz. of silver to the ton of ore, together with a little gold. Phosphate of lead, when crystallized, usually piesents the appearance of hexagonal prisms, of a bright-green, brown, or yellowish color. Its specific gravity varies from 6-5 to 7'1. This mineral is composed of a mixture of true phosphate of lead, phosphate of lime, chloride of lead, and fluoride of calcium, and usually contains about 78 per cent, of oxide of lead. In Spain, it occurs in botryoijJal forms, in connection with the sulphate of the same metal, and is treated in bla.st furnaces for the lead it affords. The other minerals containing lead seldom occur in sufficient quantities to be of mtich impf)rtance to the smelter, and may therefore be disregarded in the present article. The extraction and mechanical preparation of ores is the business of the miner, and not LEAD. 685 of the metallurgist, who receives them from the former freed as perfectly as possible from foreign matters. The metallurgic processes by the aid of which lead is obtained from galena, may be divided into two classes. The fii-st of these is founded on the following reactions: — If one equivalent of sulphide of lead and two equivalents of the oxide of the same metal are fused together, the result is three equivalents of metallic lead and one equivalent of sulphurous acid, which is evolved. This reaction is represented by the following equation: — PbS + 2FbO = 3Pb + SO'. When, on the other hand, one equivalent of sulphide of lead and one equivalent of sul- phate of lead are similarly treated, two equivalents of lead are obtained, and two equivalents of sulphurous acid gad evolved. Thus : — PbS + PbO,SO' = 2Pb + 2S0'. The process, founded on the foregoing reactions, and which we will distinguish as the method b>/ double decomposition, consists in roasting the galena in a reverberatory furnace until a certain amount of oxide and sulphate has been formed, and subsequently, al'ter hav- ing intimately mixed the charge and closed the doors of the furnace, causing the whole to enter into a state of fusion. During this second stage of the operation, the reaction between the sulphides, sulphates, and oxides takes place, and metallic lead is eliminated. The roasting of the ore is, in some cases, conducted in the same furnace in which the fusion is effected, whilst in others two separate furnaces are employed. The process by double decomposition is best adapted for the richer varieties of ore, and such as are least contaminated by silieious or earthy impurities, and is consequently that which is almost universally employed for smelting the ores of this country. By the second method, which we will call the process b>/ affinity, the ore is fused with a mixture of metallic iron, which, by combining with the sulphur, liberates the metallic lead. This reaction will be understood by reference to the following formula : — PbS -f Fe = Pb H- FeS. In practice, however, metallic iron is not always employed for this purpose ; cast iron is also frequently used, and in some instances the ores of iron and hammer slags are substi- tuted, as are also tap-cinder and other secondary products containing a considerable per- centage of this metal. None of these substances are, however, found to be so efScacious as metallic iron, since cast iron requires to be decarburized before it can readily decompose the sulphide of lead, and the ores of iron require the introduction of various fluxes, and the consequent expenditure of an additional amount of fuel. In all cases, however, it is judi- cious to subject the ore to a preliminary roasting, in order to eliminate a portion of the sul- phur, and thereby reduce the expenditure of iron, as well as to agglutinate the ore and render it better adapted for its subsequent treatment in the blast furnace. We will not attempt to describe the different forms given to roasting furnaces emploved for the ores treated by this process, but would remark tliat they frequently resemble the kilns used for the preparation of lime, whilst in some instances the ores are roasted in heaps interstratified with wood or other fuel. The method of treating ore by afpnity is particularly adapted to those varieties that contain a considerable amount of silica, since such minerals, if treated by double decompo- sition, would, by the formation of oxide of lead, give rise to silicates, from which it would be exceedingly diflScult to extract the metal. English process. Treatment by double decomposition. — Galena, if placed in a close ves- sel which protects it from the action of the air, and exposed to a gradually increasing tem- perature, becomes fused without the elimination of any lead taking place, but ultimately a portion of the sul])hur is driven off, and a subsulphide is formed, which at a very elevated temperature is volatilized without change. If, however, the vessel be uncovered, and the air allowed to act on its contents, oxygen combines with the sulphur, sulphurous acid is evolved, and the desulphuration of the min- eral is slowly effected. When galena is spread on the hearth of a reverberatory furnace, and is so placed as to present the largest possible amount of surface to oxidizing influences, it will be found that the surface slowly becomes covered with a yellowish-white crust of suljihate of lead. The oxygen of the air, by combining with the two c'ementary bodies of which galena is com- posed, will evidently produce this eflect. This is not, however, the only chemicid change which takes place in the charge under these circumstances : oxide of lead is producetl at the same time as the sulphate, or rather the formation of the oxide is prior to that of the sulphate. In fact, during the first stage of the operation of roasting suljihurous acid is evolved, the sulphur quits the lead, and a portion of that metal remains in a free state. This be- comes oxidized by the air passing through the furnace, and subsequently a part of it com- 686 LEAD. bines with sulphuric acid, formed by the oxidation of sulphurous acid, and sulphate of lead is the result. In this way, after the expiration of a certain period, both oxide and sulphate of lead are present in the furnace. . During the early period of the roasting, when the temperature of the furnace is not very elevated, the proportion of sulphate is larger than that of the oxide formed, but in proportion as the heat of the apparatus increases, the production of oxide becomes more considerable, whilst that of the sulphate diminishes. The sulphate and oxide thus formed re-act in their turn on the undecomposed galena, whilst a portion of the latter, by combining with the sulphide of lead, gives rise to the formation of oxysulphidc. This last compound has no action on galena, except to dissolve it in certain propor- tions, but is readily decomposed by the aid of carbonaceous matter. It is therefore evident that the addition of carbon, at this stage of the operation, will have the effect of reducing the oxide and oxysiilphide of lead. Every process then that has for its object the reduction of lead ores by double de- composition, comprises two principal operations: — 1st. The reduction of galena, by the aid of heat and atmospheric air, to a mixture of sulphide, oxide, and sulphate, which mutually decompose each other, with the elimination of metallic lead. 2d. The re- duction of the oxysulpliide by the addition of carbonaceous matter. The rcvcrberatori/ furnace. — The revcrberatory furnace employed for the treatment of galena is conii)oscd, like all other furnaces of this description, of three distinct parts, the fire-place, the hearth, and the chimney. The hearth has to a certain extent the form of a funnel, of which the lowest point is on the front side of the furnace immediately below the middle door. The molten metal descending from every side along the inclined bot-tom or sole, is collected in this recep- tacle, and is ultimately run off by means of a proper tap-hole. This tap-hole is, during the operation, closed by a pellet of clay. The inclination of the hearth is more rapid in the vicinity of the fire-bridge than to- wards the chimney, in order that the liquid metal may not be too long exposed to the oxidizing and volatilizing influences of a current of strongly-heated air. The dimen.sions given to these furnaces, as well as the weight of the charge operated on at one time, vary considerably in different localities, but in the north of England the following measurements are usually employed : — The fire-grate is 5 ft. 9 in. x 1 ft. 10 in., and the thickness of the fire-bridge 1 ft. 6 in. ; the length of the sole is 9 ft., and its av- erage width 7 ft. The depth of the tap is about 2 ft. 6 in. below the top of the inclined sole. The height of the roof at the fire-end may be 1 ft. 4 in., and at the other extrem- ity 11 inches. The introduction of the charge is in some cases effected by the doors of the furnace, whilst in other instances a hopper, placed over the centre of the arch, is made use of. On the two sides of the furnace are placed throe doors about 11 in. x 9 in., which are distinguished as 1, 2, and 3, counting from the fire-bridge end. The three doors on the one side are known as the front doors, whilst those on the other side are called the back doors. Immediately beneath the door on the front side of the furnace is situated the iron pan into which the molten lead is tapped off. The bottom of this arrangement is in most cases composed of fire-bricks, covered by a layer of vitrified slags, of greater or less thickness. In order to form this bottom, the slags are introduced into the furnace, the doors closed, and the damper raised. An elevated temperature is thus quickly obtained, and as soon as the scoriaj have become sufficiently fused, they are, by means of rakes and paddles, made to assume the rccjuired form. The charge cm])Ioyed, as before stated, varies in almost every establishment. In the north, however, smaller charges are used than in n;ost other localities. At New- castle, and in the neighborhood, the charge varies from 12 to 14 cwt. ; in Wales, and near Bristol, 21 cwt. charges are treated; whilst in Cornwall, charges of 30 cwt. are not unfrcquently worked. The time required for smelting a charge varies «ith its weight and the nature of the ores, from 6 to 24 hours. In some cases the ore is introduced raw into the furnace, whilst in others it under- goes a preliminary roasting previous to its introduction. Rich ores are generally smelted without being first calcined, but the poorer varieties, and particularly those which con- tnin large quantities of iron pyrites, are, in most instances, subjected to roasting in a sep- arate furnace. In order to understand more clearly the operation of smelting in furnaces of this description, we will suppose that a charge has just been tapped off, and that, after tlioroiighly clearing the hearth, a fresh charge of raw ores has been introduced. During the first part of the operation of roasting, which usually occupies about two hours, the doors arc taken ofi' to admit free access of air, and also for the purpose of cooling the furnace, which has been strongly heated at the close of the preceding operation. No fuel is at this period charged upon the grate, since the heat of the furnace is of itself suf- LEAD. 687 ficient to effect the elimination of the first portions of sulphur. The ore is carefully stin-ed, for the purpose of constantly presenting a fresh surface to oxidizing influences, and when white fumes are no longer observed to pass off in large quantities, a little coal may be thrown on the grate, and the temperature gradually elevated until the charge be- comes slightly clammy and adheres to the rake. When the roasting is considered as being sufficiently advanced, the smelter turns his attention to the state of the fire," taking care to remove the clinkers and get the grate into proper condition for the reception of a fresh supply of fuel. The furnace doors are now closed, and a strong heat is kept up for about a quarter of an hour, when the smelter examines the condition of his charge by remoTing one of the doors. If the operation is progressing satisfactorily, and the lead flowing fre^'ly and passing without obstruction into the tap, the firing is continued a little longer; bat when the ores have been found to have taken fire, or are lying uneven- ly on the"botto;n of the furnace, the position of the charge is changed by the use of an iron paddle. During this operation the furnace becomes partially cooled, and the re- duction of temperature thus obtained is frequently found to produce decompositions, which facilitate the reduction of the charge. In the case of extremely refractory ores this alternate heating and cooling of the furnace is sometimes almost indispensable, whilst, in other instances, their being once or twice raked over is all the manipulation that is required. We will suppose that four hours have now elapsed since the charging of the furnace, and that the charge has run down tlie inclined sole towards the tap. The smelter now examines the condition of the scoria and adds a CQuple of shovelfuls of hme and three or four shovelfuls of small coals, the amount and relative proportions of these being reg- ulated in accordance with the aspect of the slags. The charge is now, by means of proper tools, again raised to the breast of the furnace, and the firing continued until the charge has run down into the tap-hole. The foreman now takes his rake and feels if any lumps remain in an unfused condition, and if he finds all to be in a fluid state he calls his assistant from the other side, and by the addition of a small quantity of lime and fine coal, makes the slag assume a pasty or rather doughy consistency. By the aid of his paddie he now pushes this compound irp to the opposite side of the furnace, where it is drawn by an assistant through the back door into a trough containing water. Whilst the assistant is doing this the foreman is busily engaged in tapping off the metal into the iron pan in front of the furnace, from which, when sufiiciently cooled, it is laded out into suitable moulds. The total duration of the operation may be about six hours. To build a furnace of the above description, 5,<>0) common bricks, 2,000 fire-bricks, and 2^^ tons of fire-clay are required. In addition to this must be reckoned the iron- work, the expense of which will be much influenced by the nature of the armatures em- ployed and the locality in which the furnace is constructed. The amount of fuel employed for the treatment of a ton of lead ore varies not only in relation to the richness of the mineral, but is also much influenced by the nature of the associated matrix and the calorific value of the fuel itself. The loss of metal expe- rienced during the operation is mainly dependent on- the richness of the ore treated and the skill and attention of the foreman. In the north about 12 cwt. of coal are consumed in the elaboration of one ton of ore, and the loss of metal on 60 per cent, ore may be estimated at about 12 per cent., of which about 6^ per cent, is subsequently recovered from the slag and fumes. At a well- conducted smelting works, situated in the west of England, in which the average assay of the ores smelted d.iring the year was 75^, the yield from the smelting furnaces was 6Si per cent., and the coal used per ton of ore was 13| cwt. The lead recovered from the slag and fumes amounted to 2| per cent., making the total yield of metal 71^ per cent., and the loss on the assay produce 4+ per cent. In this establishment the men are paid from 'is. &d. to 12s. Gd. per ton of lead, in accordance with the nature of the ores operated on. In one establishment the process before described is somewhat varied. The charge employed is 21 cwt. This is run down and tapped off at the expiration of G hours, and about 9 pigs of l^ cwt. each usually obtained. A second charge of 21 cwt. is then drop- ped in, and, as soon as it is roasted, mixed with the slags of the former operation. The whole is then run down in the ordinary way, the slags drawn and the lead tapped off in 9 hours. The produce of the second or double charge is from 1-i to 15 pigs. If the ores are difficult to flow, 16 to 164 hours are required for the two charges. A small quantity of black slag from the ^lag hearth is employed for drnng up. Treatment of lead ores by the Scotch furnace or ore-hearth. — This furnace is generally employed in the counties of Northumberland, Cumberland, and Durham, for the smelt- ing of lead ores, which were formerly carried to tliem without any preparation, but th^y are now often exposed to a preliminary calcination. The roasted ore yields in the Scotch furnace a more considerable product than the crude ore, because it forms in the furnace 688 LEAD. a more porous mass, and at the same time it works drier, to use the founder's expres- sion ; that is, it allows the stream of air impelled by the blast to diffuse itself more com- pletely across the matters contained in the furnace. In proceeding to smelt by means of an ore-hearth, two workmen are required to be in attendance from the bejrinning to the end of each smelting shift, the duration of which is from 12 to 15 hours. The first step in commencing a smelting shift is to fill up the hearth-bottom and space below the workstone with peats, placing one already kindled before the nozzle of the bellows. The powerful blast very soon sets the whole in a blaze, and by the addition of small quantities of coal at intervals, a body of fire is obtained, filling the hearth. Roasted ore is now put upon the surface of the fire, between the forestone and pipestone, which inmiediately becomes heated red hot and reduced, the lead roni it sinking down and collecting in the hearth bottom. Other portions of ore of 10 or 12 lbs. each are introduced from time to time, and the contents of the hearth are stirred and kept open, being occasionally drawn out and examined upon the workstone, until the hearth bottom becomes full of lead. The hearth may now be considered in its regular working state, having a mass of heated fuel, mixed with partly fused and semi- reduced ore, called Bronze, floating upon a stratum of melted lead. The smelting shift is then regularly proceeded with by the two workmen, as follows : — The fire being made up, a stratum of ore is spread upon the horizontal surface of the Lrouze, and the whole suf- fered to remain exposed to tiie blast for the space of about five minutes. At the end of that time, one man plunges a poker into the fluid lead in the hearth bottom below the bronze, and raises the whole up, at different places, so as to loosen and open the bronze, and in doing so, to pull a part of it forwards upon the workstone, allowing the recently added ore to sink down into the body of the hearth. The poker is now exchanged for a shovel, with a head 6 inches square, with which the bronze is examined upon the work- stone, and any lumps that may have been too much fused, broken to pieces ; those which are so far agglutinated by the heat as to be quite hard, and further known by their bright- ness, being picked out, and thrown aside, to be afterwards smelted in the slag hearth. They are called "gray slags.'' A little slaked lime, in powder, is then spread upon the bronze, which has been drawn forward upon the workstone, if it exhibit a pasty appear- ance ; and a portion of coal is added to the hearth, if necessary, which the woikman knows by experience. In the mean time, his fellow workman, or shoulder fellow, clears the opening, through which the blast passes into the hearth, with a shovel, and places a peat immediately above it, which he holds in its proper situation until it is fixed by the return of all the bronze from the workstone into the hearth. The fire is made up again into the shape before described, a stratum of fresh ore spread upon the part, and the operation of stirring, breaking the lumps upon the workstone, and picking out the hard slags repeated, after the expiration of a few minutes, exactly in the same manner. At every stirring a fresh peat is put above the nozzle of the bellows, which divides the blast, and causes it to be distributed all over the hearth ; and as it burns away into light ashes, an opening is left for the blast to issue freely into the body of the bronze. The soft ' and porous nature of dried peat renders it very suitable for this purpose ; but, in some instances, where a deficiency of peats has occurred, blocks of wood of tiie same size have been used with little disadvantage. As the smelting proceeds, the reduced lead, filtering down through all parts of the bronze into the hearth bottom, flows through the channel, out of which it is laded into a proper mould, and formed into pigs. The princijial particulars to be attended to in managing an ore-hearth properly during the smelting shift, are these: First. — It is very important to employ a proper blast, which should be carefully regulated, so as to be neither too weak nor too j)Owerful. Too weak a blast would not excite the requiaito heat to reduce the ore, and one too powerful has the effect of fusing the contents of the hearth into slags. In this particular no certain rules can be given ; for the same blast is not suitable for every variety of ore. Soft free- grained galena, of great specific gravity, being very fusible, and easily reduced, requires a moderate blast ; while the harder and ligiiter varieties, many of which contain more or less iron, and are often found rich in silver, require a blast considerably stronger. In all cases, it is most essential that the blast should be no more than sufficient to reduce the ore, after every other necessary precaution is taken in working the hearth. Second. — The blast should be as much divided as possible, ami made to pass through every part of the bronze. Third. — Tiie hearth should be vigorously stirred, at due intervals, and part of its contents exposed upon the workstone; when the partially fused lumps should be well broken to pieces, as well as those which are further vitrified, so as to form slags, carefully picked out. This breaking to pieces and exposure of the hottest part of the bronze upon the workstone, has a most beneficial effect in promoting its reduction into lead; for the atmospheric air immediately acts upon it, and, in that heated state, the sul- phur is readily consumed, or converted into suliihurous acid, leaving the lead in its metallic state ; hence it is that the reduced lead always flows most abundantly out of the hearth immediately after the return of the brouze, which has been spread out and ex- LEAD. 689 posed to the atmosphere. Fourth. — The quantity of lime used should be no more than is just necessary to thicken the brouze sufficiently ; as it does not in the least contribute to reduce the ore by auy chemical effect ; its use is merely to render the brouze less pasty, if, from the heat being too great, or from the nature of the ore, it has a disposition to become very soft. Fifth. — Coal should be also supplied judiciously; too much unneces- sarily increasing the bulk of the brouze, and causing the hearth to get too full. When the ore is of a description to smelt readily, and the hearth is well managed in everv particular, it works with but a small quantity of brouze, which feels dry when stirred, and is easily kept open and permeable to the blast. The reduction proceeds rapidly with a moderate degree of heat, and the slags produced are inconsiderable : but if in this state the stirring of the brouze and exposure upon the workstone are discontinued, or practiced at longer intervals, the hearth quickly gets too hot, and immediately begins to agglutinate together ; rendering evident the necessity of these operations to the suc- cessful management of the process. It is not difficult to understand why these effects take place, when it is considered, that in smelting by means- of the ore-hearth, it Ls the oxygen of the blast and of the atmosphere which principally accomplishes the reduction; and the point to be chiefly attended to consists in exposing the ore to its action, at the proper temperature, and under the most favorable circumstances. The importance ©f having the ore free from impurities is also evident ; for the stony or earthy matter it contains impedes the smelting process, and increases the quantity of slags. A very slight difference of composition of perfectly dressed ore may readily be understood to affect its reducibility ; and hence it is, that ore from different veins, or the same vein in different strata, as before observed, is frequently found to work very differently when smelted singly in the hearth. It happens, therefore, that with the best workmen, some varieties of ore require more coal and lime, and a greater degree of heat than others ; and it is for this reason that the forestone is made movable, so as either to answer for ore which works with a large or a small quantity of brouze. It has been stated that the duration of a smelting shift is from 12 to 15 hours, at the end of which time, with every precaution, the hearth is apt to become too hot, and it is necessary to stop for some time, in order that it may cool. At mills where the smelting shifts is 12 hours, the hearths usually go on 12 hours, and are suspended 5 ; four and a half or five bings* of ore (.36 to 40 cwt.) are smelted during a shift, and the two men who m;inage the hearth work each four shifts per week; terminating their week's work at 3 o'clock on Wednesday afternoon. They are succeeded by two otherworkmen, who also work four 12-hour shifts; the last of wliich they finish at -i o'clock on Satur- day. In these eight shifts from 36 to 40 bings of ore are smelted, which,, when of good quality, produce from 9 to 10 foddersf of lead. At other mills where the shift is 14 or 1-5 hours, the furnace is kindled at 4 o'clock in the morning, and worked until 6 or 7 in the evening each day, six days in the week ; during this shift, 5 or 5^ bings of ore are smelted, and two men at one hearth, in the early part of each week, work three such shifts, producing about 4 fodders of lead — two other men work each 3 shifts in the latter part of the week, making the total quantity smelted per week, in one hearth, from SO to 33 bings. Hearth-ends and Smelter's fume. — In the operation of smelting, as already described, it happens that {wrticles of unreduced and semi-reduced ore are continually expelled from the hearth, partly by the force of the blast, but principaHT by the decrepitation of the ore on the application of heat. This ore is mixed with a portion of the fuel and lime made use of in smelting, all of which are deposited upon the top of the smelting hearth, and are called hearth-ends. It is customary to remove the hearth-ends from time to time, and deposit them in a convenient place until the end of the year, or some shorter period, when they are washed to get rid of the earthy matter they may contain, and the metallic portion is roasted at a strong heat, until it begins to soften and cohere into lumps, and afterward^ smelted in the ore-hearth, exactly in the some way as ore under- going that operation for tbe first time, as already described. It is difficult to state what quantity of hearth-ends are produced by the smelting of a given quantity of ore, but in one instance the hearth-ends produced in smelting 9,751 bings, on being roasted and reduced in the oar-hearth, yielded of common lead 315 cwt., and the gray slags separated in this process gave, by treatment in the slag-hearth, 47 cwt. of slag lead; making the total quantity of lead 362 cwt., which is at the rate of 3 cwt. 2 qrs. 23 lbs. from the smelting of 100 bings of ore. Sing-hearth. — The various slags obtained from the different operations of lead smelt- ing are divided into two cla-sses. Those which do not contain a sufficient amount of metal to pay for further treatment are thrown away as useless, whilst those in which the percentage of lead is sufficiently large are treated by the slag-hearth. Castilian furnace. — Within the last few years a blast furnace has been introduced into the lead works of this country, which possesses great advantages over every other * 1 bing = S cwts, + 1 fjd.)or = 21 cwts. Vol. III. — i4 690 LEAD. description of ajiparatus which has been hitherto employed for the treatment of lead ores of low produce. This apparatus, although first employed in Spain, was invented bv an Englishman (Mr. W. Goundry) who was employed in the reduction of rich slags in the neighborhood of Carthagena. This furnace is circular, usually about 2 feet 4 inches, or 2 foct 6 inches in diameter, and is constructed of the best fire-bricks, so moulded as to fit together, and allow iiU the joints to follow the radii of the circle described by the brickwork. Its usual height is 8 feet 6 inches, and the thickness of the masonry invariably 9 inches. In this arrangement the breast is formed by a semicircular plate of cast-iron, furnished with a lip for running oif the slag, and has a longitudinal slot, in which is placed the tapping-hole. On the top of this cylinder of brickwork, a box-shaped covering of masonry is sup- ported by a cast-iron framing, resting on four pillars, and in this is placed the door for ieeding the furnace, and the outlet by which the various products of combustion escape to the flues. The lower part of this hood is fitted closely to the body of the furnace, whilst its top is closed by an arch of 4T!-inch brickwork laid in fire-clay. The bottom is composed of a mixture of coke-dust and fire-clay, slightly moistened, and well beaten to the height of the top of the breast-pan, which stands nearly 3 feet above the level of the floor. Above the breast-pan is an arch, so turned as to form a soit of niche, 18 inches in width and rather more than 2 feet in height. When the bottom has been solidly beaten, up to the required height, it is hollowed out so as to form an internal cavity, communicating freely with the brea.=t-pan, which is filled with the same material and subsequently hollowed out to a depth sliglitly below the level of the internal cavity. The blast is supplied by three water tuyeres, 3 inches in diameter at the smaller end, 5^ inches at the larger, and 1(» inches in length. Into these the nozzles are introduced, by which a cm-rent of air is supplied by means of a fan or vcntilatoi', making about SoO revolutions per minute. The blast may be conveniently conducted to the nozzles through brick channels formed beneath the floor of the smelt- ing house. The ores treated in this furnace ought never to contain more than 30 per cent, of metal, and when richer, must be reduced to about this tenure by the addition of slags and other fluxes. In charging this apparatus, the coke and ore are supplied stratum super stratum, and care must be taken so to dispose the coke as not to heat too violently the brickwork of the furnaces. In order to allow the slags which are produced to escape freely into the breast-pan, a brick is left out of the front of the furnace at the height of tlie fore-hearth, which, for the purpose of preventing the cooling of the scoriae, is kept covered by a layer of coke-dust or cinders. From the breast pan the slags flow constant- ly off over a spout into cast-iron wagons, where they consolidate into masses, having the form of truncated pyramids, of which the larger base is about 2 feet square. As soon as a sufficient amount of lead is accumulated in the bottom of the furnace, it is let off into a lateral lead-pot, by removing the clay-stopper of the tap-hole situated in the slot of the breast-pan, and after being properly skimmed it is laded into moulds When in addition to lead, the ore treated likewise contains a certain portion of copper, this metal will be found in the form of a matt floating on the surfi.ce of the leaden bath. This, when suf- ficiently solidified, is removed, and after being loastcd is operated on for the copper it contains. » The wagons in which the liquid slag runs off, are frequently made to traverse small railways, by which, when one mass has been removed, its place may readily be supplied by an empty wagon. When nearly cold the casings of the wagons are turned over and the blocks of slag easily made to drop out. In addition to the facility for transport obtained in this way, one of the great advantages obtained by this method of manipu- lation arisesfrom the circumstance, that should the furnaces at any time run lead or matt, without its being detected by the smelter, the whole of it will be collected at the bottom of the block, from which, when cold, it may be readily detached. In working these furnaces, care must be taken to jirever.t flame from appearing at the tunnel-head, since, provided the slags are sufficiently liquid, the cooler the apparatus is kept the less will be the loss of metal through volatilization. In addition to the great- est attention being paid to the working of the furnace, it is necessary, in order to obtain the best results, that all establishments in which this apparatus is employed should be provided with long and capacious flues, in which the condensation of the fumes takes place, previous to arriving at the chimney-shaft. These flues should be built at least three feet in width and six feet in height, so as readily to admit of being cleaned, and are often made of several thousand yards in length. The value of the fumes, so con- densed, amounts to many hundreds, and in some instances thousands per annum. In order to be advantageously worked in these furnaces, the ores should be first roast- ed, and subsequently agglomerated into masses, which, afrer being broken into fragments of about the size of the fist, and mixed with the various fluxes, are charged as before described. LEAD. 691 In an establishment in which the average assay produce of the roasted ore for lead is 42* stbs, the furnace yield is 38" nths, and the weight of coke employed to eflect the reduction 22 per cent, of the roasted ore operated on. The mixture charged into the furnace, in this instance, is composed of luu parts of roasted ore, 42 parts of slags from a previous operation, 8 parts of scrap iron, and 7 parts of limestone. Each furnace works off about seven tons of roasted ore in the course of 24 hours ; the weight of slags ruji off is about double that of the lead obtained, and the matt removed from the surface of the pan is nearlv 5 per cent, of the lead produced. The ores treated in this establish- ment consist of galena, much mixed with spathose iron, and are therefore somewhat re- fractorv. A furnace of this kind requires for its construction about 1,000 segmental fire- bricks, and the same number of ordinary fire-bricks of second quaUty. 374 ST 5 692 LEAD. Fifjs. 374, 375, 376, and 377 represent respectively a vertical section, an elevation, a grouml plan, and a horizontal section of a Castilian furnace. The section {fig. 377) is oil the line x y, {fig. 375.) a is the body of the furnace, b, the bottom composed of a nii.^turc of coke-diist and fire-clay; c c c, the tuyeres; d, the rectangular covering of masonry ; E e E e, cast-iron pillars , F, the breast-pan ; g, slot for tapping hole ; n, lip of breast-jiiiu ; i, feeding door; k, Hue-hole; p, q, ground line. Figs. 378, 379 are the sLig-wasons, a being a movable case without a bottom, and B a strong cast-iron plate running on four wheels. 378 The dosulphuration of the ores to be treated in these furnaces may be effected either by the aid of an ordinary reverberatory roasting furnace, or in heaps, or properly con- structed kilns. The Kilns bi>st adapted for this purpose consist of rectangular chambers, having an arched roof, and provided with proper fines for the escape of the evolved gases, as well as a wide door for charging and withdrawing the ore to be operated on. Eich of these chambers is capable of containing from 25 to 30 tons of ore, and, in onier to ih^rge it, a hiycr of faggots and split wood is laid on the floor, and this, after having been covered by a layer of ore about two feet in thickness, is ignited, care being at the same time taken to close, by means of loose brick-work, the opening of the door to the same height. When this first layer has become sufficiently ignited, a fresh stratum of ore, mixed with a little coal or charcoal, is thrown upon it, and when this layer has in its turn become sufficiently heated, more ore is thrown on. In this way, more ore is from time to time added, until the kiln has become full,, when the orifice of the doorway is closed by an iron plate, and the operation proceeds regularly and without further trouble until the greater portion ha-; become eliiidnated. This us'ially happens at tlio expiration of about four w eeks from the time of first igni- tion, and tlie brick-work front is then removed, and the ores broken out, and, after being mixed with proper flu.xes, passed through the blast furnace. The propoitir)n of wood necessary for the roasting of a ton of ore by this means, nmst necessiirily defx-nd on the composition of the minerals operated on ; but with ores of the dcscri[)tion nbove mentioned, and in a neighborhood where wood is moderately cheap, the desul|ihuialion may be effected at a cost of about 6s. per ton. Calcining — The lead obtained by the various processes above described, generally contains a snfTieictit amount of silver to render its extraction of much importance; but, in aildition to tliis, it is not unfrequently associated with antimony, tin, copper, and various other impurities, which require to be removed before the separation of the silver can be effected. This operation consists in fusing tlie hard lead in a reverberatory furnace of peeidiar construi-tio'i, and allowing it to reinaiii, when in a melted state, exposed to the oxidizing influences of the gases passing through the apparatus. By this treatment the antimony, copper, and other impurities become oxidized, and on rising to the surface of the metallic bath are skimmed ofl", and removed with an iron rake. The hearth of the furnace in which this operation is conducted consists of a large cast-iron pan, which may be 10 feet in length, 5 feet t; inclics in width, and 10 inches in depth. The fire-place, which is 1 foot 8 iiiciies in width, has a length equal to the width of the pan, and is separated from it by a fire-bridge '1 feet in width. The height of the arch at the bridge end is 1 foot 4 inches above the edge of the pan, whilst at the outer extremity it is only about 8 inches. The lead to be introduced into the pan is first fused in a large iron ]>ot fixed in brick- work at the side of the furnace, and subsequently laded into it through an iron gutter LEAD. 693 adapted for that purpose. The length of time necessary for the purification of hard lead obviously depends on the nature and amount of the impurities which it contains; and, consequently, some varieties will be sufficiently improved at the expiration of twelve hours, whilst in other instances it is necessary to continue the operation during three or four weeks. The charge of hard lead varies from eight to eleven tons. When the metal is thought to be in a fit state for tapping, a small portion taken out with a ladle, and poured into a mould used for this purpose is found on cooling to assume at the surface a peculiar crystalline appearance, which when once seen is readily agiin rec- ognized. As soon as this appearance presents itself, an iron plug is withdrawn from the bottom of the pan, and the lead run oif into an iron pan, from which it is subsequently laded into moulds. The items of cost attending the calcination of one ton of hard Spanish lead iii the north of England are about as follows :—' Wages Coals, 2-7 cwt. Repairs, &c. d. 11-2 4-7 0-5 2 4-4 The coBstruction of a furnace of this description requires 5,000 common bricks, 3,500 fire-bricks, and i tons of firc-:lay. Figs. 380 and 381 represent an elevation and vertical section of the calcining furnace. E m E E 3S1 A is the fire-place ; b, ash-pit ; c, fire-bridge; d, cast-iron pan ; e, flue ; r K F, channels for allowing the escape of moisture ; g, one of the working doors ; b, spout for running off calcined metal. Fi^. 382 represents the pan removed from the masonry, and shows a groove in the hp for the introduction of a sheet-iron dam tightened with moistened bone-ash, for keeping in the fused metal. In the more modern furnaces of this de- scription, the corners are usually rounded to prevent breakage from expansion, whilst the tapping is effected by means of a hole through tiie bottom near one of the sides. This, when closed, is stopped by means of an iron plug kept in its place by a weighted lever. Concentration of the silver. — This process is founded on the circumstance first noticed in the year 1829, by the late H. L. Pattinson of Newcastle-on-Tyne, that when lead con- taining' silver is melted in a suitable vessel, afterwards slowly allowed to cool, and at the same kept constantly stirred, at a certain temperature near the melting point of lead. ^i: 694 LEAD. 383 384 metallic crystals begin to form. These as rapidly as they are produced sink to the bot- tom, and on being removed are found to contain much less silver than the lead originally operated on. The still fluid portion, from which the crystals have been removed, will at the same time be proportionally enriched. This operation is conducted in a series of 8 or 10 cast iron-pots, set in a row, with fire- places beneath. These are each capable of containing about 6 tons of calcined lead ; and on commencing an operation, that quantity of metal, containing we will suppose 20 oz. of silver per ton, is introduced into a pot (say r, fir). 383) about the centre of the series. This, when melted, is carefully skimmed with a per- forated ladle, and the fire immediately with- drawn. The cooling of the metal is also fre- quently hastened by throwing water upon its surface, and whilst cooling it is kept constantly agitated by means of a long iron stirrer or slice. Crystals soon begin to make their ap- pearance, and these as they accumulate and fall to the bottom are removed by means of a large perforated ladle, in which they are well shaken, and afterwards carried over to the next pot to the left of the workman. This operation goes on continually until about 4 tons of crystals have been taken out of the pot F, and have been placed in pot e, at which time the pot f, may contain about 40 oz. of silver to the ton, whilst that in e, will only yield 10 oz. The rich lead in f is then laded into the next pot g, to the right of the work- man, and the operation repeated in f, on a fresh quantity of calcined lead. In this way, calcined lead is constantly introduced, and the resulting poor lead passes continually to the left of the workman, whilst the rich is passing towards his right. Each pot in succession, when filled with lead of its proper produce for silver, is in its turn crys- tallized, the poor lead passing to the left of the workman, and the enriched lead to his right. By this method of treatment, it is evi- dent that the crystals obtained from the pots to the left of the workman must gradually be deprived of their silver, whilst the rich lead passing to his right becomes continually richer. The final result is, that at one end of the series, the poor lead contains very little silver, whilst at the other an exceedingly rich alloy of lead and silver is obtained. The poor lead obtained by this process should never contain more than 12 dwts. of silver per ton, whilst the rich lead is fre- quently concentrated to 500 oz. to the ton. This rich lead is subsequently cupelled in the refining furnace. The ladle employed for the removal of the crystals, when manual labor is made use of, is about 16 inches in diameter, and 5 inches in depth, but when cranes are used much larger ladles are easily managed. A form of crane has been invented which effects considerable economy of labor in this operation. When, during the operation of crystallization, the ladle becomes chilled, it is dipped in a small vessel containing lead of a higher temperature known by the name of a temper-pot. The pot than that which is beincr worked, and LEAD. 695 containing the rich lead is generally called the No. 1 pot ; in some establishments, howerer, the last pot in which the poor lead is crystallized obtains this appellation. Ficfs. 383 and 384 represent a plan and elevation of a set of Pattinson's pots, arranged in the most approved way. a is the " market pot," from which the desilverized lead is laded out. b, c, d, e, f, g, h, and i, are the working pots, whilst a', b', c', d', e', f', g', h', and I, are their respective fireplaces. The " temper-pots" a a a a, are employed for heating the ladles when they have become too much reduced in temperature. Thejjgs. 385 and 386 are sections showing the manner of setting and the arrangement of the pots and flues, a, pot ; b, main flue ; c, ash pit. 886 The cost of crystallizing one ton of calcined Spanish lead, in the establishment quoted when treating of calcination, is as follows ; — s. d. "Wages 9 5-4 Coals, 4 cwt. 8-4 Repairs 2-5 Total 10 4-3 The erection of nine six-ton pots requires 15,000 common bricks, 10,000 fire-bricks, 160 feet of quarles, 80 fire-clay blocks, and 5 tons of fire-clay. In some establishments, ten-ton pots are employed, and where cranes are made use of they are found to be advantageous. Jiejininrf. — The extraction of the silver contained in the rich lead is conducted in a cupel forming the bottom of a reverbcratory furnace called a refinery. In this operation the litharge produced, instead of being absorbed by the substance of the cupel, is run off in a fluid state, by means of a depression called a gate. The size of the fire-place varies with the other dimensions of the furnace, but is usually nearly square, and in an apparatus of ordinary size may be about 2 feet -(- 2 feet C inches. This is separated from the body of the furnace by a fire-bridge 18 inches in breadth, so that the flame and heated air pass directly over the surface of the cupel, and from thence escape by means of two separate apertures into the main flues of the establishment. The cupel or test consists of an oval iron ring, about 5 inches in depth, its greatest diameter being 4 feet and its lesser nearly 3 feet. This frame, in order to better support the bottom of the cupel, is provided with cross-bars about i^ inches wide, and one-half inch in thickness. In order to 696 LEAD. make a test, this frame is beaten full of finely-powdered bone-ash, slightly moistened with water, containing a small quantity of pearl-ash in solution, which has the property of giving consistency to the cupel when heated. The centre of the test, after the ring has been well filled with this mixture, and solidly beaten don-n, is scooped out with a small trowel, until the sides are left 2 inches in thickness at top, and 3 inches at the bottom, whilst the thickness of the sole itself is about 1 inch. At the fore part or wide end of the test, tlie thickness of the border is increased to 6 inches, and a hole is then cut through the bottom, which communicates with the openings or gates by which the fluid litharge makes its escape. The test, when thus prepared, is placed in the refinery furnace, of which it forms the bottom, and is wedged to its proper height against an iron ring firmly built into the masonry. When this furnace is first lighted, it is necessary to apply the heat very gradually, since if the test were too strongly heated before it became perfectly dry, it would be liable to crack. As soon as tlie test has become thoroughly dry, it is heated to incipient redness, and is nearly filled with the rich lead to be operated on, which has been previously fused in an iron pot at the side of the furnace, and beneath which is a small grate where a fire is 1 ghted. The melted lead, when first introduced into the furnace, becomes covered with a grayish dross, but on further increasing the heat, the surface of the bath uncovers, and ordinary litharge begins to make its appearance. The blast is now turned on, and forces the litharge from the back of the test up to the breast, where it passes over the gate, and tails through the aperture between the bone-ash and the ring into a small cast-iron pot running on wheels. The air, which is supplied by a small ventilator, not only sweeps the litharge from the surface of the lead towards the breast, but also supplies the oxygen necessary for its formation. In proportion as the surface of the lead becomes depressed by its constant oxidation, and the continual removal of the resulting litharge, more metal is added from the melting pot, so as to raise it to its former level, and in this manner the operation is continued until the lead in the bottom of the test has become so enriched as to render it necessary that it should be tapped. The contents of the test are now so far reduced in volume that the whole of the silver contained in the rich lead operated on remains in combination with a few hundred weight only of metal, and this is removed by carefully drilling a hole in the bone-ash forming the bottom of the test. The reason for the remgval of the rich lead, is to I)revent too large an amount of silver from being carried off in the litharge, which is found to be the case when lead containing a very large amount of that metal is operated on. When the rich lead has been tlius removed, the tapping-hole is again closed by a pellet of bone-ash, and another charge immediately introduced. As soon as the whole of the rich lead has been subjected so cupellation, and has become thus further enriched, the argentiferous alloy is itself similarly treated, either in a fresh test, or in that employed for the concentration of the rich lead. The brightening of pure silver at the moment of the separation of the last traces of lead, indicates the precise period at which the operation should be terminated, and the blast is then turned off, and the fire removed from the grate. The silver is now allowed to set, and as soon as it has become hardened, the wedges are removed from beneath the test, which is placed on the floor of the establishment. When cold, the silver plate is detached from the test, and any adhering particles of bone- ash removed by the aid of a wire brush. A test furnace of ordinary dimensions requires for its construction about 2,000 common bricks, 2,000 fire-bricks, and H tons of fire-clay. A furnace of this kind will work off 4 pigs of lead per hour, and consume 4 cwt. of coal per ton of rich lead operated on. The cost of working a ton of rich lead in the neighborhood of Newcastle, containing on an average 400 oz. of silver per ton, is as follows : — s. d. Refiner's wages 42'1 Coals, 4 cwt. 06-8 Engine wages .- 17 '0 Coals, 5 cwt. 8-7 Pearl-ash 3-5 Bone-ash, 17-3 lbs. 3 1-0 Repairs 5-0 Total 10 10-1 Figs. 387, 388, and 389, represent an elevation, plan, and section of a refining furnace ; A, fireplace ; b, ash-pit ; c, fire-bridge ; d, test-ring, sho^^Ti in its proper position ; e, flues ; F, point where blast enters ; g, pig-holes.* * Pig-holes are used for introducing the lead In cases in which it is not laded into the test in a fused itate. E.ducir,,.-T,e reduction to thc.n,eta iic « J^ " , , ^ S cJ"S S^c^^'-^ po,, ,l,oss, a^d the mixed metallic -'' '^ ^'7; ' uin^S ' wo ex^^^^^ hat its din,ension« 'v,.,.l,erato.7 apparatus, somwhat re^e^W, g ^^j^'^^^^-^/^^Su-'lv below "the n.iddle .loor, an- suKdhT, and the sole instead of ''^^ owest im u j aepression in xvhieh gradually slope. from .he ^^^:^]'\^";:';;^ZX^nJ^o^X^f^ou. M the reduced i;;;:^^fl::i=e;:i;;uS:'i.S -ulNr i:::;&y ^h^ side of the t^maco ^o. ■.. recep. ^'^'^^^^S;g':?';rr^!; ist:th:a;d;m;S ..th a quantity of smaU coal, and i. 698 LEAD. charged on that part of the hearth immediately before the fire-bridge. To prevent the fused oxide from attacking the bottom of the furnace, and also to provide a sort of hollow filter for the liquid metal, the sole is covered by a layer of bituminous coal. The heat of the furnace quickly causes the ignition of this stratum, which is rapidly reduced to the state of a spongy cinder. The reducing gases present in the furnace, aided by the coal mixed with the charge itself, cause the reduction of the oxide, which, assum- ing the metallic form, flows through the interstices of the cinder, and ultimately finding its way into the depression at the extremity of the hearth, flows through the iron gutter into the external cast-iron pot. The surface of the charge is frequently, during the pro- cess of elaboration, turned over with an iron rake, for the double purpose of exposing new surfaces to the action of the furnace, and also to allow the reduced lead to flow ofl" more readily. Fresh quantities of litharge or pot dross, with small coals, are from time to time thrown in, in proportion as that already charged disappears, and at the end of the shift, which usually extends over 12 hours, the floor of cinder is broken up, and after being mixed with the residual matters in the furnace, is withdrawn. A new floor of cinders is then introduced, and the operation commenced as before. A furnace of this kind, having a sole 8 feet in length and 7 feet in width, will aflbrd, from litharge, about 5^ tons of lead in 24 hours. The dross from the calcining pan, when treated in a furnace of this description, should be previously reduced to a state of fine division, and intimately mixed up with small coal and a soda-ash. In many cases, however, the calcined dross is treated in the smelting furnace. The hard lead obtained from this substance is again taken to the calcining fur- nace, for the purpose of being softened. The expense of reducing one ton of litharge may be estimated as follows : — s. d. Wages 2 60 Coals, 3 cwt. 5-2 Repairs -0 1*6 Total - - - - 3 0-8 In the establishment from which the foregoing data were obtained, the cost of slack, delivered at the works, was only 2s. \\d. per ton, which is cheaper than fuel can be ob- tained in the majority of the lead-mills of this country. In North Wales the cost of small coal is generally about 4s., and at Bristol 5s. 6dfor the purpose of cooling the condensers, ex- cellent results are generally obtained. — J. A. P. See LiTUARGE, Minicm, or Red Lead, Solder, ScG.iR or Acetate of Lead, and White Lead. LEAD ORES, ASSAY OF. The ores of lead may be divided into two classes. The first clans comprehends all the ores of lead which contain neither sulphur nor arsenic, or in which they are present in small profiortion only. The .iec(md class comprises galena, together with all lead ores containing sulphur, arsenic, or their acids. From the facility with which this metal is volatilized when strongly heated, it is neces- sary to conduct the assay of its ores at a moderate temperature. A common wind-furnace is best adapted lor making lead assays. For this purpose the cavity for the reception of fuel should be 9 inches square, and the height of the flue- way from the fire-bars about l-l inclies. For ordinary ores a furnace 8 inches square and 12 inches deep will be found sufiiciciit ; l)Ut as it is easy to regulate, by a damper, the heat of the larger apparatus, it is often found advantageous to be able to produce a high temperature. A furnace of this kind should be connected with a chimney of at least twenty feet in height, and be supplied with good coke, broken into pieces of the size of eggs. Ores of the First Cla.ss. — The assay of ores of this class is a simple operation, care being only required that a sufficient amount of carbonaceous matter be added to effect the reduction of the metal, whilst such fluxes are supplied as will afford a readily-fusible slug. When the sample has been properly reduced in size, 40" grains are weighed out and well mixed with 600 grains of carbonate of soda, and from 40 to 60 grains of finely-powder- ed charcoal, according to the richness of the mineral operated on. This is introduced into an earthen crucible, of such a .'^ize as not to be more than one- half filled bv the mixture, and on the top is placed a thin layer of common salt. The crucible is then placed in the furnace and gently heated, care being taken to so moderate the tempi'raturc that the mixture of ore and flux, which soon begins to soften and enter into ebullition, may not swell up and flow over. If the action in the crucible becomes too strong, it must be checked by removal from the fire, or by a due regulation of the heat by means of a damper. When the action has subsided, the temperature is again raised for a few minutes, and the assay comfilcted. During the process of reduction, the heat shoulil not exceed dull redness; but in order to complete the operation, and render the slag sufficiently liquid, the temperature should be r^iiscd tu bright redness. When the contents have been reduced to a state of trancpiil fusion, the crucible must be removed from the fire and the assay either rapidly poured, or, after being tapped against some htird body to collect the lead in a single globule, be set to cool. When the operation has been successfully conducted, the cooled slag will present a smooth concave surface, with a vitreous lustre. When cold, the crucilile may be broken, and the button extracted. To remove from it the particles of adhering slag, it is hammered on an anvil, and afterwards rubbed with a hard brush. Instead of employing carbonate of soda and powdered charcoal, the ore may be fused wi'h H times its weight of black flux, and the mixture covered by a thin layer of borax. Good results are also obtained by mixing together 400 grains of ore with an equal weight of carbonate of soda and half that quantity of crude tartar. These ingredients, after being well incorporated, are placed in a crucible, and slightly covered by a layer of borax. LEAD ORES, ASSAY OF. 701 Each of the foregoing methods yields good results, and affords slags retaining but a small proportion of lead. Ores of the Second Class. — This class comprehends galena, which is the most common and abundant ore of lead, and also comprises sundry metallurgic products, as well as the sulphates, phosphates, and arseniates of lead. Galena. — The assay of this ore is variously conducted ; but one of the following methods is usually employed for commercial purposes. Fusion iciih an alkaliJie fux. — This operation is conducted in an earthen crucible, which is to be kept uncovered until its contents are reduced to a state of perfect fusion. The powdered ore, after being mixed with three times its weight of carbonate of soda and 10 per cent, of finely pulverized charcoal, is slowly heated in an ordinary assay fur- nace until the mixture has become perfectly liquid, when the pot is removed from the fire, and. after having been gently tapped, to collect any globules of metal held in sus- pension in the slag, is put aside to cool. When sufiiciently cold, the crucible is broken, and a button of metallic lead will be found at the bottom : this must be cleansed and weighed. In place of carbonate of soda, pearlash may be employed, or the fusion may be efiFect- ed with black flux alone. When the last-named substance is used, a somewhat longer time is necessary for the complete fusion of the assay. Each 100 parts of pure galena will by this method afford from 74 to 7t3 parts of lead. Some of the old assayers were in the habit of first driving off the sulphur by roasting, and afterwards reducing the resulting oxide with about its own weight of black flux. This method, from the great fusibility of the compounds of lead, requires very care- ful management, and at best the results obtained are un.satisfactory. Pure galena by this method can rarely be made to yield more than 70 per cent, of lead. fusion with metallic iron. — Mix the ore to be assayed with twice its weight of carbon- ate of soda, and, after having placed it in an earthen crucible, of which it should occupy about one half the capacity, insert with their heads downward three or four tenpenny nails, and press the mixture firmly around them. On the top place a thin layer of borax, which should be again covered with a Uttle common salt. The whole is now introduced into the furnace and gradually heated to redness ; at the expiration of ten minutes the tem- perature is increased to bright redness, when the fluxes will be fused and present a per- fectly smooth surface. When this has taken place, the pot is removed from the fire, and the nails are separately withdrawn by the use of a small pair of tongs, care being taken to well cleanse each in the fluid slag until free from adhering lead. When the nails have been thus removed, the pot is gently shaken, to collect the metal into one button, and laid aside to cool ; after which it may be broken, and the button removed. Instead of first allowing the slags to cool and then breaking the crucible, the assay may, if preferred, after the withdrawal of the nails, be poured into a mould. Assay in an iron pot. — Instead of adding metallic iron to the mixture of ore and flux, it is generally better that the pot itself should be made of that metal. For this purpose, a piece of half-inch plato-iron is turned up in the form of a crucible and carefully welded at the edges. The bottom is closed by a thick iron rivet, which is securely welded to the sides, and the whole then finished on a properly formed mandril. To make an assay in a crucible of this kind, it is first heated to dull redness, and, when sufficiently hot, the powdered ore, intimately mixed with its own weight of carbonate of soda, half its weight of pearlash, and a quarter of its weight of crude tartar, is introduced by means of a copper scoop. On the top of the whole is placed a thin layer of borax, whilst the crucible, which, for the ready introduction of the mixture, has been removed froiTi the fire, is at once replaced. The heat is now raised to redness, the contents gradu- ally becoming liquid and giving off large quantities of gas. At the expiration of from eight to ten minutes the mixture will be in a state of complete fusion ; the pot is now partially removed from the tire, and its contents briskly stirred with a small iron rod. Any matter adhering to its sides i? also scraped to the bottom of the pot, which, after be- ing again placed in a hot part of the furnace, is heated during three or four minutes to bright redness. The crucible is then seized by a strong pair of bent tongs, on that part of the edge which is opposite the lip, and its contents rapidly poured into a cast-iron mould. The sides of the pot are now carefully scraped down with a chisel-edge bar of iron, and the adhering particles of metallic lead added to the portion first obtained. When sufficiently cooled the contents of the mould are easily removed, and the button of lead cleaned and weighed. By this process pure galena yields 84 per cent, of metallic lead, free from any injurious amount of iron, and perfectly ductile and malleable. This method of as.-saying is that adopted in almost all had-smelting establishments, and has the advantage of affording good results with all the ores belonging to the second class. Assay in the iron dish. — In some of the mining districts of Wales, the assay of lead 702 LEAD, OXICIILOEIDE OF. ore is conducted in a manner somewhat different to that just described. Instead of fusing the ore in an iron crucible with carbonate of soda, pcarlash, tartar and borax, the fusion is effected in a flat iron dish, without the admixture of any sort of flux. — J. A. P. LEAD, OXICIILOEIDE OF. A white pigment patented by Mr. Hugh Lee Tattinson of Newcastle, which he prepares by precipitating a solution of chloride of lead in hot water with pure lime water, in equal measures; the mixture being made with agitation. As the operation of mixing the lime water, and the solution of chloride of lead, require to be performed in an instantaneous manner, the patentee prefers to employ for this pur- pose two tumbling boxes of about 16 feet cubic capacity, which are charged with the two liquids, and simultaneously up: et into a cistern in which oxichloride of lead is instantane- ously formed, and from which the mixture flows into other cisterns, where the oxichloride subsides. This white pigment consists of one atom of chloride of lead and one atom oxide of lead, with or without an atom of water. LEATHER, {t'uir, Fr. ; Leder, Germ. ; Leer, Dutch ; Lceder, Danish ; Ldder, Swedish ; Cuojo, Italian; Cucro, Spanish ; Kuslia, Russian.) This substance consists of the skins of animals chemically changed by the process called tanniiu/. Throughout the civilized world, and from the mo.">t ancient times, this substance has been cnii>loyed by man for a variety of purposes. Barbarous and savage tribes use the skins of beasts as skins; civilized man renders the same substance unalterable by the external agents which tend to decompose it in its natural state, and by a variety of peculiar manipulations prepares it for almost innumerable applications. Although the preparation of this valuable substance in a rude manner has been known from the most ancient times, it was not until the end of the last, and tlie beginning of the present century (180(») that it began to be manufactured upon right principles, in consequence of the researches of Macbride, Deyeux, Seguin, and Davy. Skins may be converted into leather either with or without their hair ; generally, how- ever, the hair is removed. The most important and costly kinds are comprised under sole leather and upper leather, to which may be added harness leather, belts used in machinery, leather hose, &c. ; but as far as the tanner is concerned, these are comprehended almost entirely in the kinds known as upper leather. The active principle by which the skins of animals are prevented from putrefying, and at the same time, under some modes of preparation, rendered comparatively impervious to water, is called tannin, or tannic acid, a property found in the bark of the various .species of Quercus, but especially plentiful in the gall-nut. When obtained pure, as it may easily be from the gall-nut, by chemical means, tannic acid appears as a slightly yelloiAish, almost a colorless mass, readily soluble in. water ; it precipitates gelatin from solution, forming what has been called tannogelalin. Tannic acid also precipitates albumen and starch. There can be little difficulty, after knowing the chemical combination just alluded to, in understanding the peculiar and striking change produced on animal substance in the forma- tion of leather. The hide or skin consists principally of gelatin, fur which the vegetable astringent tannin has an affinity, and the chemical union of these substances in the process of taiming produces the useful article of which we are treating. Before entering upon the various processes by which the changes are effected on the animal fibre, it may not be uninteresting to speak of some of the principal astringents used for the purpose of producing these effects. Bark obtained from the oak-tree is the most valuable and the most extensively used ingredient in tanning, and for a long time no other substance was used in England for the purpose. In consequence of the demand having become very much greater than the sup- ply, and the consequent increase in the price of the article, it became necessary to investi- gate its properties, in order, if possible, to furnish the rcciuired quantity of tanning matter from other sources. Among other substitutes which wore tried with some success in other countries, may be mentioned heath, myrtle Icai'C'!, viUl laurel leajr^, birch tree bark, and (according to the Fciiny Cyclopadin) in 1765 oak sawdust was applied in England, and has since been used in Germany for this purpose. Investigation proved that the tanning power of oak bark consisted in a peculiar astrin- gent property, to which the name of tannin has been given, and this discovery suggested that other bodies possessing this property would be suitable substitutes. According to Sir II. Davy, the following proportions of tannin in the different substances mentioned will be found : — " 8^ lbs. of oak bark are equal to 2\ lbs. of galls, to 3 lbs. of sumach, to 7 J lbs. of bark of Leicester willow, to 11 lbs. of the bark of the Spanish chest- nut, to 18 lbs. of elm bark, and to 21 lbs. of common willow bark." — Penny Cyclopadin. Oak b.\rk contains more tannin-when cut in spring by four and a half times, than when cut in winter ; it is also more plentiful in young trees than in old ones. About 40,000 tons of oak bark are said to be imported into this country annually, from the Netherlands, Germany, and ports in the Mediterranean. The quantity of English oak bark used we have no means of ascertaining. It is prepared for use by grinding it to a coarse powder between LEATHER, CURRYING OF. 703 cast-iron cylinders, and laid into the tan-pits alternately with the skins to be tanned. Some- times, however, as will be hereafter noticed, an infusion of the bark in water is employed with better effect. Mimosa. — The bark and pods of several kinds of Prosopis, the astringent properties of which have rendered them valuable in tanning, are known in commerce by this name. The Mimosa; are a division of the leguminous order of plants, which consists of a large number of species, the Acacia being the principal. The sensitive plants belong to this division. The proposis is found in India and South America ; the genus consists both of shrubs and trees. Valonia. — The oak which produces this acorn is the Quercus jSyilop^, or great prickly S92 393 - 97 - 73 - 16 - 14 The legumes of cupped oak, {figs. 392, 393.) These are exported from the Morea and Levant ; the husk contains abundance of tannin. Catechu, or Terra Japomca, is the inspissated extract of the Acacia catechu. At the time the sap is most perfectly formed the bark of the plant is taken off, the tree is then felled, and the outer part removed ; the heart of the tree, which is brown, is cut into pieces and boiled in water ; when sufficiently boiled it is placed in the sun, and, subject to various manipulations, gradually dried. It is cut into square pieces, and nmeh resembles a mass of earth in appearance ; indeed, it was once considered to be such, hence the name Terra Japonica. We give Sir H. Davy's analysis ; the first numbers represent Bombay, the second Bengal catechu : — Tannin 10.9 • - Extractive -..-...68-- Mucilage - - 13- Impurities -- 10-- This astringent is also obtained from the Uncaria Gambir. Divinivi is a leguminous plant of the genus Ciesalpiuia, C. coriaria. this species are extremely astringent, and contain a very large quantity of ^^^ tannic and gallic acid ; they grow in a very peculiar manner, and become curiously curled as they arrive to per- fection. The plant is a native of America, between the tropics. Fig. 394. SnMACn is a plant belonging to the genus Rhus ; several of the species have astringent properties ; lihus co'i- nus and Rhus coriaria are much used in tanning ; the bark of the latter is said to be the only ingredient used in Turkey for the purpose of converting gelatin into leather. That used in this country is ground to a fine powder, and is extensively applied to the production of bright leather, both l)y tanners and curriers. Many other vegetable products have been from time to time proposed, and to some extent adopted for the same end, l)ut thev need not l)c enumerated. LEATHER, CURRYING OF. The currici's .'-hop has no resemblance to the premises of the tanner, the tools and manipulations being quite different. Within the last twenty or thirty year,'^, many tanners have added the currying business 704 LEATHER CURRYING OF. to their establishments, and many curriers have likewise commenced tanning ; but in each case, an extension of premises is necessary, and the two departments are still separate. The advantages derivable from this arrangement are twofold, — first, a saving of time is effected, for as the tanned leather is sold by weight, it is required to be well dried belbre being disposed of to the currier — an operation which is not needed where the tanner carries on the currying also ; and secondly, by the currier's art, the skins can be reduced to a com- paratively uiiitorm thickness previous to their being tanned, thus saving ti)»e and bark, (used for tanning,] and insuring a more equal distribution of tannin through the substance of the skin. In the following description, the business of currying will be considered as practised at the present time : — The currier's shop or premises, to be convenient, should be spacious. A frequent, though not universal method, is to have the ground-floor appropriated to such operations as require the use of a large quantity of water. The place or apartment thus used, is called the scoiiriurf-Iioiise, and is commonly furnished with a number of vatx or casks open at one end, in which the leather is placed for the purpose of soaking, and undergoing such treat- ment as will be hereafter described. In this apartment also is placed a large, flat, slate stone, called a scouringslone, or, more consistently, the stone on which the leather is scoured. This stone, which has its face perfectly flat and smooth, and which should meas- ure 8 or 9 feet in length, by 4| broad, forms a table, supported generally by masonry, but sometimes by a strong frame of wood, so constructed, that the water, which is freely used in scouring, may drain off on the opposite side from that on which the workman is en- gaged ; an inclination of about three or four inches on the width of the table is sufficient for this purpose. Another piece of furniture very frequently found in, or on Uie same /loor with the scouring-house, is a block of sandstone, in the form of a parallelopipedon, between 2 and 3 feet long, and 9 or 10 inches broad, the upper face of which is kept as near as possible a perfect plane ; this stone is fixed at a convenient height on a strong trussel, and is called the rub-stone, because here the workman rnbs or sharpens his knives and other tools. In some large establishments where the premises and water are heated by steam, the scouring-house will be found with a service of pipe leading to the various vats, and the boiler, for generating the steam, may be conveniently placed in or near this part of the building. The floor above the scouring-house, in the arrangement here laid down, is what is spe- cially designated the shop. The furniture in this department consists of a beam, (ficj. 295,) on which the leather is shaved. It consists of a heavy 395 block of wood, on which the workman stands, and into one end of which a stiff piece of wood is firmly mor- tised, at an angle of about 85° ; this upright (so called) is about a foot wide, the height being greater or less, according to the height of the workman, each of whom has his beam adjusted to meet his convenience. On the front of the itprirjht, a piece of deal is firmly screwed, to which is glued a face or plate of lignum vitcB, worked to j)crrect smoothness to agree with the edge of the knife used in the operation of shaving. It is of the greatest importance to the workman, to keep his shin from injury, that his knife and beam should be kept in good order A table or tables, gen- erally of mahogany, large planks of which are used for the purpose to avoid joints, may be said to form a necessary part of the furniture of this department. These tables are firmly fixed, to resist the pressure of the workman when using various tools ; and as light is of the greatest con- sequence in the operations performed on them, they are usually placed so as to have win- dows in front of them. A high trussil is frequently used, across which the leather is thrown, after undergoing any of the processes, while the currier subjects other pieces to the same operation. Another part of the premises is termed the driiing-loff. In good buildings the drying- loft is surrounded with veather-boards, constructed to be opened or closed as may be re- quired. The use of this part being the drying of the leather, the ceiling is furnished with a number of rails or long pieces of wood, with hooks or nails on which to hang the leather for drying, and whore steam is used for this purpose, the floor is traversed with pipes for heating the lof:. Here also is a table, similar to that previously described ; it should not ^o,', be less than 7 or 8 feet long by 4| broad, if possible, — ' without joint, and with a smooth face. ) I ^^^ g^ - — -=gj ""i^^^^ i * There are other subordinate departments, each [ ^ ^~ ~ -° - — ° -^P^'^^' ' furni.shed with a table similar to those described. \ I c Of the tools used in currying, the knife stands first in importance, ( fig. 39G.) Here a and b are two handles ; a is held in the left hand, and forms a powerful lever when the edge c is !ipj)lied LEATHER, CURRYING OF. 705 to the leather. The blade of the currier's knife is peculiarly tempered ; it is composed of a plate of fine steel, strongly riveted between two plates of iron. This instrument is taken to the rub-stone, and ground to a perfectly sharp edge by successively rubbing forward and backward ; care being taken to keep the edge true, that is, straight. When this has been satisfactorily accomplished, it is still further rubbed on a fine Scotch or Welsh stone called a clearing-stone, until the scratches of the rub-stoiie disappear. In this operation a fine thread or wire forms on the edges, for the knife has two edges (<■ c) which must be carefulily got rid of; after which it is wiped dry, and the edges greased with tallow or oil. The workman then takes a strong steel, and placing himself on his knees, he fixes the knife with the straight handle h against any firm body, and the cross handle a between his knees ; then holding the steel in both hands he carefully rulis it for- ward and backward the whole length of the edge. During this operation the knife is gradu- ally raised by means of the handle a until it is nearly perpendicular ; by this means the edge is turned completely over. If the knife is not well tempered, the edge thus obtained will be irregular, or broken ; in either of which cases it is of no use whatever. To keep the instrument just described in proper order requires great skill on the part of the currier. The edge is so delicate and liable to injury that it cannot be used 397 more than a minute or two without losing its keenness. To restore this, a very care- fully prepared small steel is used, fg. 397 ; the point of the steel is first run along the groove which is formed by turning the edge over, and the steel is then made to pass outside the edge. It is remarkable that a skillful hand can thus restore the effi- ciency of the knife, and keep it in work for hours without going for a new edge to the rub-stone. The other tools will be described as their uses are mentioned. The first thing done by the currier is the soaking of the leather received from the tanner in water ; the skin requires a thorough wetting, but not to saturation. In some cases the thicker parts are partially soaked before the immersion of the whole, and when from the nature of the skin this cannot be done, water is applied to the stout parts of the dip- ping ; it is requisite that the whole should be as near as possible equally wet. In some 399 400 c ^^^'^ ^Crj:^, ^S^^i^^^M^ instances the wetted leather is beaten, and sometimes a coarse grainingboard (hereafter to be described) is used, to make it more supple previous to shaving it. The skin is then laid over the beam, {fg. 399,) and the rough fleshy portion is Bliaved off. This operation is Vol. III. — 15 T06 LEATHER, CURRYING OF. generally called skiving. In all the operations at the beam, the leather is kept in its place by pressure of the knees or body of the workman from behind. In skiving, the right hand handle of the knife somewhat precedes the left, but in shaving, properly so called, the kit hand precedes the right, fig. 400. In skiving, the knife is Oriven obliquely a few inches at a time ; in shaving, it is driven with great force, not unfrequently from the top to the bot- tom of the beam ; great skill is requisite in the performance of these operations, to guide the knife and to keep its edge. The carpenter's plane can be most completely regulated by the projection of the plane-iron from the wood, but the currier's knife admits of no such arrangement, and the unskilful currier is constantly liable to injure the leather by cutting through it, as well as by failing to produce a regular substance. The kind of skin, and the use for which it is designed, will regulate the work at the beam. In some cases, as in tlie calf-skin, it is skived and then shaved, or (as it is called) fattened at right angles to the skiving — in other kinds, as the cow-hide prepared for the upper leather of heavy shoes, after skiving it is shaved acvo.'is, {i. e. nearly at right anglea to the skiving,) and flattened by being again shaved in the same direction as the skiving. In some manufactories there are certain kinds of leather which are subjected to the operation called by curriers stoning, before fattening : this is done by forcibly driving the stock-stone {Jig. 401) over the grain 401 402 side of the leather, thereby stretching it and rendering the grain smooth. The fattening process is considerably facilitated by this stoning, and if the skin has been allowed slightly to harden by exposure to air, and the edge of the knife is fine, as it should be, the work- man has but to strike the flat part of the knife over the leather after the shaving is per- formed, to produce a beautiful face to the flesh side of the skin. It will not be difficult to understand that a good hand is easily distinguished from an inferior one in this part of the business. With such nicety will a skilful workman set the edge of his knife, that although there seems nothing to guide him, he can take shaving after shaving from the hide, extend- ing from the top to the bottom of the beam, thus rendering the leather extremely even in its substance. After the process of shaving is completed, the leather is placed in water, where it remains until it is convenient to carry on the operation next required. It is to be observed,' that in the condition in which leather is shaved, it cannot long be kept without becoming heated ; when, however, it is i)ut into water, it is safe from injury, and may be kept a very long time, provided the water be occasionally changed for a fresh, sweet supply ; stale water is regarded as injurious for the skin to remain in. Scouring is next proceeded with ; the skin is taken out of the water, and laid on the scouring-stone. In respectable manufactories, it is usual first to scovr on the fesh ; this is done by passing a slicker smartly over the flesh side, by which the grain of the leather is brought into close contact with the scouring-stone, and, being in a wet condition, the air is easily excluded, so that the leather sticks to the stone. A plentiful supply of water is now applied, and a large brush, with stiff hairs, is rubbed over the flesh, or upper side. Por- tions of the surface, in a pulpy condition, come off with the scrubbing, and the skin pre- sents a soft, whitened, pulpy appearance ; the pores are rendered capable of containing more moisture, and, altogether, the leather is much benefited. The slicker is a plate of iron or steel, or for particular purposes, of brass or copper ; it is about five inches long, and, like the stock-stone, is fixed in a stock, or handle, {fig. 402.) It is sharpened at the rub-stone, by grinding the plate perpendicularly, and then on either side, thus producing two edges, (or rather, right angles.) The edges thus produced are not of an order to cut the leather, but rather to scrape it. The slicker is not intended to remove irregularities in the leather, but its uses are various, and it may be considered a very in:portant tool, as will hereafter appear. In the process of tanning, the grain side of the hide or skin becomes covered with a whitish body, derived from the bark called bloom ; this is more or less difficult to remove, according to the hardness or softness of the water used in tanning, and the peculiar treat- ment of the tanner. It is, however, the currier's business to remove it, which he effects thus : — In the case of leather, whose grain is tender, as cordovan, which is manufactured from horse hides, the grain being kept uppcnnost, the leather is spread on the scouring- stone, and being plentifully supplied with water, is stretched by using the slicker, or a fine pebble, ground to the shape of the stock-stone the bloom ; is thus loosened, and, at the same time, by making it adhere to the scouring-stone, the next operation is readily carried on, which consists in smartly brushing the grain with a stiffhaired brush, at the same time keep- ing a quantity of water on the surface, flie slicker is again used to remove the water and LEATHER, CURRYING OF. 707 loosened bloom, and the scouring is complete. In the scouring of calf-skins, and cow or ox hides, the stock-stone is used to fix the leather, and a piece of pumice-stone, the face of which has been ground to smoothness, and afterwards cut in grooves, is then forcibly rubbed over the grain, in order to remove the bloom. In this, as in other operations on the scour- ing-stone, water is a necessary ingredient. The bloom being sufficiently loosened by the pumice-stone, the brush is used to scrub up the remaining dirt, which is then removed by the stock-stone or slicker. In harness leather, which is stout, and requires to be stretched as much as possible, the pumice-stone is seldom used, the stock-stone and scouring-orush being lustily applied until the bloom is sufficiently removed. Ordinary manufacturers within the present (nineteenth) century, have considered the operations of the scourmg-honse com- plete at this point. The modern currier takes a different view, and not unfrequently detains his scoured property for days, and sometimes for weeks, in the scouring-house. If the leather is imperfectly tanned, or it is required to be made of a bright color, there are other processes to be passed through. In these cases sumach (an evergreen shrub of the natural^rder Anacardiacece, genus Ukus, and from the bark of which all the leather made in Turkey is said to be tanned) is infused in boiling water, and when cooled to a tepid state the leather is placed in it. After staying a sufficient time it is taken to the scouring- stone ; if cordovan, it is slicked as dry as can be well accomplished on the Jlesh side ; other leather is for the most part slicked in a similar way on the grain side. Saddle leather which is required to be of a bright color is still farther placed in warm water slightly acidulated with sulphuric or oxalic acid, or- both ; here for a time it is kept in motion, then taken to the scouring-stone, it is washed with peculiar chemical lotions, according to the taste or knowledge of the workman ; then again it is dipped in tepid sumach infusion, then slicked with a copper or brass slicker, (iron is liable to stain leather thus prepared,) and a thin coat of oil being applied to either side,, it is removed to the drying-loft. Until within a very few years, much time and trouble were taken to produce very bright leather for the sad- dler ; but of late, brown-colored leather has been adopted to a considerable extent, as it is less liable to become soiled. Nearly all leather is placed a short time in the loft before far- ther manipulations are carried on, in order to harden it slightly by drying. In the drying-loft, or its immediate vicinity, the leather receives the dubbing (daubing, probably) or stuffing. The substance so called is composed of tallow brought to a soft plastic condition by being melted and mixed with cod-liver oil ; occasionally sod (an oil made in preparing sheep-skins) is in very small quantities added to the mixture. This is laid upon the leather either with a soft-haired brush, or a mop made generally of rags. The leather is prepared for stuffing by wetting slightly such parts as have become too dry. It is then taken to the table previously described, which being slightly oiled, the pro- cess is carried on by placing the skin on the table in the manner most convenient for stretch- ing it and making the surface smooth. In those kinds that have a rough wrinkled grain, the flesh side is placed next the table and tlie stock-stone is used very smartly to stretch and smooth the grain. A kind of clamp or holdfast, composed of two checks fastened with a screw, is sometimes used to prevent the leather from moving during this operation, but in general these are not required ; the slicker is then applied to remove the marks left by the stock-stone, and a thin stuffing being spread over the grain, it is turned over, slicked on the flesh lightly, a coat of stuffing is sjiread over it, and it is hung up to dry. In those kinds which have to be blacked (or stained) on the grain, a little cod oil only is spread on the grain, and the slicker is applied on the flesh side most laboriously previous to stiffing. Much skill is required to give the requisite quantity of stuffi (dubbing) to the leather with- out excess, excess being injurious, and the quantity required is farther regulated by the freshness or otherwise of the leather, the tan-yard from which it comes, and the treatment it has received in the scouring-house. When dry, the skins or hides are folded together, to remain until required. It is cer- tain the leather improves by remaining some weeks in this condition. It should be ob- served that, in drying, the leather absorbs a large quantity of the oleaginous matter with which it is charged, and the unabsorbed portion forms a thick coating of hardened greasy matter on the flesh side. Leather which has to be blackened on the flesh, (uux leather,) from this point, receives different treatment from grain leather. Wax leather is taken to the shop-table and softened 403 '-^^. '^~^'«^A/^A^A;^.N»'^-'''^ with a graining-board. The skin is laid on the table and doubled, grain to grain, the grain- wi^-board, {fig. 404,) which is confined to the hand by a leather strap, (a a,) is driven for- 708 LEATHER, CUERYING OF. ward and drawn back alternately until a grain is raised on the leather, and it has attained the required suppleness. Observe, the graiuing-board is slightly rounded on the lower sur- face, aiid traversed by parallel grooves from side to side, which are coarser or finer, as occa- sion reiiuires. The grease is next removed from tlie flesh by the slicker, and afterwards a sharp s.icker is passed over the grain to remove grease or other accumulations from it. The next process is called nfiiteniiiff. The leather is laid over the bccan, and a knife with an extremely fine edge is used to take a thin shaving from the flesh side ; this is a point at which a currier's sldll is tested. The knife used is one that has been very much worn, the quality of which has been tested to the utmost ; and so extremely true is the edge ex- pected, that not the slightest mark (^^crafc/i) is allowed to appear on the surface of the leather. Only a good workman can satisfactorily accomplish tliis. The slightest gravel in the flesh of the skin may break the edge of the knife in pieces, and it is not easy to rectify so serious a misfortune ; besides, a poor workman may tear up the edge by steeling, an operation which ought to mend the mischief instead of provoking it. ^ A fine (jrainhiff-board is next used to soften the leather ; the stiffer parts being boarded both on the grain and flesh sides, and the operation being carried on in two or three direc- tions, to insure both softness and regularity of grain. Boarding is performed by doubling the leather and driving the double part forward and drawing it backward by the graining- board. The leather is now prepared for the waxer, and passes, consequently, into his hands. Waxing, in large establishments, is a branch considered separate from the general business, and is usually in the hands of a person who confines himself to this occupation alone. The skin is laid on a table, and the <;oA)>- rubbed into the flesh side with a brush. It is necessary to give the brush a kind of circular motion to insure the rec)uired blackness in the leather. The rii/or 'S made by stirring a quantity of the best lampblack into cod-liver oil ; sometimes a little dubbing is added, and in order to make it work smoothly so as not to clog the brush, some stale tan-water from the vats in the scouring-house is beaten vp with the mixture until it combines therewith. The preparation of the color is an important affair, and requires i considerable amount of time and labor to render it such as the ivaxcr desires. A .ilick-sfone, or gtasx, is next used ; this tool is aliout the size and shape of the slicker, but instead of being ground like it, the edges are very carefully removed, so that while, fr(jin end to end, it preserves nearly a right line, it is circular across the edge. The stone (a fine pebble) is little used now, plate-glass being substituted for it. The use of the tool just described is to smooth the flesh after the operation by the coloring brush, thereby get- ting rid of any marks made on the surface. The next step in waxing is what is called sizing. Size is prepared by boiling glue in water — the melted glue is diluted with water to the extent required — in some cases it is softened by mixing cod-liver oil with it in cooling. When cold, it is beaten up with various ingredients, according to the taste or experience of the waxer ; the waxer then well rubs the size into the colored side of the leather, and with a sponge, or, more generally, the fleshy part of his hand, smooths it off. When dry, the slick-stone, or glass, is again ap- plied, thus producing a polish on the size ; and a very thin coat of oil completes the work. In ditfereiit manufactories different methods are pursued, but the above is convenient and satisfactory in almost all circumstances. It is now ready for the shoemaker. Leather intended to be blacked on the grain, is lelt folded up when dry after stuffing. Some years ago it was the custom to stain these kinds of leatlior, while wet in the scouring- house, by spreading stale urine over it and then applying a solution of copjieras, (sulphate of iron.) That method is now exploded. The dry skins or pieces of leather are laid on the shop-board : a brush is used to saturate the graiii with urine, or as is now more com- mon, a solution, of soda in water, and a peculiar preparation of iron in solution is afterwards laid over it, which blackens the surface. It may be observed that in wax-leather a body of black is laid on, and rubbed into the flesh ; in grain leather the black is a stain. After the blackening, it is necessary to rub a small quantity of oil or dubbing over the blackened sur- face, then turning the oiled grain towards the table, a sharp slicker is used on the flesh side ; the leather sticks to the table by means of the oil, and the slicker is driven so smartly ovtr it, that it is stretched on the table, at the same time that the grease is removed. It is quite an imj)ortant point to take all the stretch out of the leather in this operation, after which it is turned over ; the table is covered with a very thin coat of liard tallow, a roll of tallow being rubbed over the table, for the purpose of keeping the leather fastened to it. A dull .slicker is used on the grain to remove remaining marks and wrinkh^s, or to smooth any coarse appearance on the grain ; a sharp slicker removes all the grease, and a thin coat of weak size, made of glue dissolved in water, is spread over it, and the process, usually called seasoninfi, is completed. The next object is carefully to dry the seasoned leather, and in this state it may be .stored without injury. The next step is very similar to that described in the case of vax-leather, and called whitening : — it is then softened by means of a fine graining-board, or a board of the same shape and size covered with cork, the grain side is placed next the table, and the flesh LEATHER, CURRYIXG OF. 709 doubled against the flesh, and thus driven forwards and backwards until the required degree of suppleness is obtained. The loose particles of flesh are brushed off, and u slicker care- fully passed over the grain removes all >h«/-^.< of the last operation. If a sufficiency of stuff has not been applied in the drying-loft, the deficiency is remedied by a coat of ta low- dubbing now spread over the grain, and allowed to remain soaie l:oars. As the leather absorbs the oily matter, a hardened coat of grease has to be removed by the aid of the slicker. Tne leather is then sized, and a very thin coat of o.l spread over the size com- pletes the operation. In the preparation of various kinds of leather, or of leather for particular purposes, the currier has particular appliances. Harness leather is considerably dryer than o:i;er kinds te'bre s uffing, and is subjected to immense labor by the stock-stone and slicker, to procure a smootu grai.i. It is blackened when dry like other gmin leather, but instead uf the oil- ing and other processes described, the hardest tallow procurable is rubbed into it, stoned with a fine pebble, slicked, and tallow again rubbed into it by the hand. Wuen dry after this operation, the grease is slicked from the flesh side, and a repetition of the tallowing, stoning, and rubbing finishes the work. Saddle leather, which is cut into comparatively small pieces, after hardening in the dry- ing-loft, is passed through a very different process from any described previously. Tlie skin of the hog is much used for certain parts of hackney saddles, and the bristles, when re- moved by the tanner, leave indentations, or even holes in the tanned skin. Probably it was deemed desirable to obtain some imitation for the parts of the saddle where the bog skin was not suitable. The skin of the dog-fish (^Scyllium, Cuv ) to some extent supplied the imitation, having hard tubercles on its surface. At first the skin was laid on the leather, and lustily pressed into it by rubbing it with a pebble or plate of glass ; at length a press was invented, and more recently various methods have been proposed to produce the best effect. We have here {fig. 405) a representation of one of these presses, which may stand 405 <^e e&^ --^■= E==S=i -j==-=~^^^:'--^- ^ .4 \==^ |\ ^ ^;t, I 1 _j «k \ as a type of all others ; a a are the feet into which the uprights are inserted ; b b arc the two upright sides tied at the top by c / a similar cross-piece ties them a little above the feet ; concave grinding tool itself, and also that of the polisher. These polishers are adjustod with great accuracr. The concave tool is placed upon the convex, and thev are first rubbed tcgnher dry, so that by the brightened parts the inequalities may be distinguished; they are then ground true, first by means of emery and water, and tlien with dry emery. The following figure (409) represents those tools, which are fitted with screws at the back so that they can be fixed upon pillars in connection with the machinery for giving motion to them. By grinding with sundry niceties of motion which are re- quired to produce the best eftect, such as the production of mo- tion which shall resemble as nearly as possible the kind of stroke which would be given by the hand, these tools are eventually brought to true spherical figures which fit each other exactly. The glasses for lenses being selected of suitable quality, they are brought to a circular form by means of flat pliers called \^ -^^^ ^ shanks. The pressure of the pliers, applied near the edges of the glass, causes it to crumble away in small fragments, and this process, which is called shankinrj or nibbling, is continued until fie ghisscs are made circular, and of a little larger diameter than tlie finished size of the lenses. A cement is made by mixing wood ashes with melted pitch. Some nicety is required in the adjustment of the proportion, since the cement must not be too adhesive, nor must it hi too hard or too brittle : generally about 4 lbs. of wood ashes to 14 lbs. of pitch are em- ployed. This when melted is poured on one side of the glasses to be ground, in small quantities at a time, until a sufficient quantity adheres to the back of the lens to form a liandl2. The glass is rough ground by rubbing it within the spherical shell. The glass is niljbed with large circular strokes, and the shell is usually placed within a shallow tray to catch the loose emery or polishing powder which may be employed. When one side is rough ground in this way, the glass is warmed to detach it from the handle, which is trans- ferred to the other side and the operation repeated. When both sides are thus rudely formed, the lenses are cemented upon a runner. The best object-glasses for telescopes are ground and polished singly, while as many as four dozen of common spectacle-glasses are grouid and polished together. When many are thus fixed on one runn t, the number must be such as will admit of their being ar- ranged symmetrically around a central lens, as 7, 13, or 21 ; or sometimes 4 form the nucleus, and then the numbers run 14, 30. Lenses of ordinary quality are usually ground true and polished 7 at a time. This runner, with its lenses attached, is shown m fg. 410. The cement at the back of the lenses is first flattened with a heated iron. The cast-iron runner is heated just sufficiently to melt the cement, and carefully placed upon the cemented backs of the lenses. As soon as the cement is sufficiently softened to adhere firmly to the runner, it is cooled with a wet sponge, as the cement must only be so far fused as to fill up the spaces nearly, but not quite, level with the surface of the lenses. The block of lenses is now mounted upon a post, and ground with the concave brass tool, {fig. 409,) motion being given to it either by the hand or by machinery similar to the sweeping motion already named. As the griading proceeds, the fineness of the emery powder employed is increased, until in the last operation it is sufficiently fine to produce a semi-polished surface. This grinding being completed successfully, the lenses have to be polished. The polisher is made by warming a cast-iron shell and coating it uniformly about one-quarter of an inch thijk with melted cement. A piece of thick woollen cloth is cut to the size of the polisher and secured to it, and pressed into form by working the brass tool within it. When this is properly adjusted it is covered with very finely divided putty powder, sprinkled with a little water, and the powder worked into the pores of the cloth with the brass convex tool. Ite- peated supplies of p' tty powder are put on the polisher until it is made quite level, and it is worked smooth with the tool. Many hours are expended in the proper preparation of a polisher. When completed it is placed upon the block of lenses still fixed to the post, and worked with wide and narrow elliptical strokes. Where a very large number of glasses are grounil or polished at the same time, this peculiar motion is imitated by the eccentric move- ment of a lever attached to the revolving shaft. In the processes of grinding and polishing, other materials besides emery and putty powder are sometimes employed, such as raddle, a'l earthy oxide of iron, the finer kinds of which are much employed in the large lens man- ufactory at Sheffield. Much more might be said on the subject of grinding and polishing lenses, but it is one of those processes of manufacture which scarcely come within the limits of the present work. Still it was thought to be of sufficient importance to receive some general notice. The grinding and polisliing of the finer varii^ties of lenses for telescopes, microscopes, and the like, require extremely nice manipulation. The best account of the processes and of the instruments used is one by the late Andrew Ross, in the fifly-third volume of YU LIGHT. the Tmnsactions of the Society of Arts. In IloltzapffePs Mechanical 3Ia7iip2daiion there is also some very excellent practie;;! information. LIGHT. {Lumiere, Fr. ; Licht, (ierm.) The operation of light as an agent in the arts or manufacturers has scarcely yet received attention. Sufficient evidence has, however, been collected to show that it is of the utmost importance in producing many of the re- niarliable changes in bodies which are desired in some cases as the result, but which, in others, are to be, if possible, avoided. There is a very general misconception as to the power or principle to which certain phenomena, the result of exposure to sunshine, are to be referred. In general light is regarded as the principle in action, whereas frequently it has nothing whatever to do with the change. A few words, therefore, in explanation are necessary. The solar rays commonly spoken of as light contains in addition to its Inminoits power, calorific power, chemical power, and in all probability electrical power. These phenomena can be sepa- rated one from the other, and individually studied. All the photographic phenomena are dependent upon the chemical (actinic) power. Many of the peculiar changes which are effected in organic bodies are evidently due to light, and the phenomena which depend entirely on heat are well known. Ilerschel has directed attention to some of the most striking phenomena of light, especially its action upon vegetable colors. As these have direct reference to the per- manence of dyes, they are deserving of great attention. The following quotation from Sir John Herschell's paper " On the Cheviical Action of the Rays of the Solar Spectrum, dr.," will explain his views and give the character of the phenomena which he has stud- ied. He writes: — " The evidence we have obtained by the foregoing experiments of the existence of chemical actions of very different and to a certain extent opposite characters at the oppo- site extremities (or rather, as we ought to express it, in the opposite regions) of the spectrum, will naturally give rise to many interesting speculations and conclusions, of which those I am about to state will probably not be regarded as among the least so. We all know that colors of vegetable origin are usually considered to be destroyed and whitened by the continual action of light. The process, however, is too slow to be made the subject of any satisfactory series of experiments, and, in consequence, this subject, so interest- in"- to the painter, the dyer, and the general artist, has been allowed to remain uninves- tigated. As soon, however, as these evidences of a counterbalance of mutually opposing actions, in the elements of which the solar light consists, offered themselves to view, it occurred to me, as a reasonable subject of inquiry, whether this slow destruction of veg- etable tints might not be due to the feeble amount of residual action outstanding after imperfect mutual compensation, in the ordinary way in which such colors are presented to light, i. e. to mixed rays. It appeared, therefore, to merit inquiry, whether such colors, subjected to the uncompensated action of the elementary rays of the spectrum, might not undergo changes differing both in kind and in degree which mixed light produces on them, and might not, moreover, by such changes indicate chemical properties in the rays themselves hitherto unknown. " One of the most intense and beautiful of the vegetable blues is that yielded by the blue petals of the dark velvety varieties of the connnon heartsease {Viola tricolor). It is best extracted by alcohol. The alcoholic tincture so obtained, after a few days' keeping in a stoppered phial, loses its fine blue color, and changes to a paUid brownish red, like that of port wine discolored by age. " When spread on paper it hardly tinges it at first, and might be supposed to have lost all coloring virtue, but that a few drops of very dilute sulphuric acid sprinkled over it, indicate by the beautiful and intese rose color developed where they fall, the continued existence of the colaring principle. As the paper so moistened with the tincture dries, however, the original blue color begins to appear, and when quite dry is full and rich. The tincture by long keeping loses this quality, and does not seem capable of being restored. But the paper preserves its color well, and is even rather remarkable among vegetable colors for its permanence in the dark or in common daylight. " A paper so tinged of a very fine and full blue color, was exposed to the solar spec- trum concentrated, as usual, (October 11, 1839,) by a prism and lens ; a water-prism, how- ever, was used in the experiment, to command as large an area of sunbeam as possible. The sun was poor and desultory; nevertheless in half an hour there was an evident commencement of whitening from the fiducial yellow ray to the mean red. In two hours and a half, the sunshine continuing very much interrupted by clouds, the effect was marked by a considerable white patch extending from the extreme red to the end of the violet ray, but not traceable beyond that limit. Its commencement and termination were, how- ever, very feeble, graduating off" insensibly ; but at the maximum, which occurred a little below the fiducial point, (corresponding nearly with the orange rays of the luminous spectrum,) the blue color was completely discharged. Beyond the violet there was no indication of increase of color, or of any other action. I do not find that this paper is discolored by mere radiant heat unaccompanied with light." LIGHT-HOUSE. 715 Dr. George Wilson of Edinburgh made some exceedingly interesting experiments on the injiucnce of sunlight Oder the action of the dry gases on organic colors. The results arrived at were communicated to the British Association, and an abstract of the com- munication is published in their transactions. The experiments were on chlorine, sul- phurous acid, sulphuretted hydrogen, carbonic acid, and a mixture of sulphurous and carbonic acid, oxygen, hydrogen, and nitrogen, on organic coloring matters. "I had ascertained," says Dr. George Wilson, " the action of the gases mentioned already on vegetable coloring matters, so arranged that both coloring matter and gas should be as dry as possible, the aim of the inquiry being to elucidate the theory of bleaching, by accounting for the action of dry chlorine upon dry colors. In the course of this inquiry, I ascertained that in darkness dry chlorine may be ke[)t for three years in contact with colors without bleaching them, although when moist it destroys their tints in a few sec- onds, (see Bleaching;) and I thought it desirable to ascertain whether dry chlorine was equally powerless as a bleacher when assisted by sunlight. The general result of the inquiry was, that a few weeks sufficed for the bleaching of a body by chlorine in sun- light, where months, I may even say years, would not avail in darkuess. " The form of the experiment was as follows: — Four tubes were connected together so as to form a con- tinuous canal, through which a current of gas could be sent. Each tube contained a small glass rod on which seven pieces of differently colored papers were spiked. It is not necessary liere to state the colors employed, suffice it to say, that all the tubes thus contained seven different colored papers, of different origins, and easily distinguishable by the eye. They were arranged in the same order in each tube, and were prepared as nearly as possible of the same shade. These papers were carefully deprived of every trace of moisture by a current of very dry air. The tubes were then filled with the gas, also dried, on which the experiment was to be made. One tube of each series was kept in darkness, two others were exposed in a western aspect behind glass, and the other was turned to the south in the open air. The results were as follows : — In the dark chlorine tube the colors were very little alter- ed, and would probably have been altered less had not the tube been frequently exposed to light for the sake of examination. In the western tube, the original gray and green wallflower papers became of a bright crimson, the blue htmus bright red, and the brown rhubarb yellow. The whole of the chlorine had apparently entered into combination with the coloring matters, for the yellow tint of the gas had totally disappeared. In the southern tube the color of the chlorine could still be seen, the reddening action was less decided, and the bleaching action was more powerfully evinced. The general result was that the action of sunlight is less uniform than might have been expected in increasing the bleaching power of chlorine, or while some tints rapidly disappeared under its action assisted by light, other colors remained, in apparently the very same circumstances, unaffected. Sulphurous acidy if thoroughly dried, may be kept for months in contact with dry colors without altering them ; under the influence of sunlight it however recovers to some extent its bleaching power. Sulphuretted hydrogen acts as a weak acid, and readily as a bleacher when moist, and becomes inactive in both respects if made dry and kept in darkuess. With the assist- ance of sunlight it recovers in no inconsiderable degree its bleaching power. Oxygen is a well-known bleaching agent, but when dry its action upon coloring mat- ter in the dark is extremely slow. In sunlight, however, it recovers its bleaching power. Carbonic acid, when dry in darkness, loses all power on coloring matter, but a faint bleaching action is exerted by it under exposure to sunlight. Hydrogen is without any action when dry upon colors, but it acquires a slight decol- orizing power when exposed to sunshine. " The general result, " concludes Dr. George Wilson, " of this inquiry, so far as it has yet proceeded, is, that the bleaching gases, viz., chlorine, sulphurous acid, sulphuretted hydrogen, and oxygen, lose nearly all their bleaching power if dry and in darkness, but all recover it, and chlorine in a most marked degree, by exposure to sunlight." All these experiments appear to show that the action of the solar rays on vegetable colors is dependent upon the power possessed by one set of rays to aid in the oxida- tion or chemical changes of the organic compound constituting the coloring matter. The whole matter requires careful investigatiou. It is a proved fact, that coloring matters, either from the mineral or the vegetable king- doms, are much brighter when they arc precipitated from their solutions in bright sun- shine, than if precipitated on a cloudy day or in the dark. It must not be supposed that all the changes observed are due to chemical action ; there can be no doubt but many arc purely physical phenomena, that is, the result of molecular change, without any chemical disturbance. LIGHT- IIOUSI]. The importance of lights of great power and of a distinguishable character around our coasts is admitted by all. One of the noblest efforts of humanity 716 LIGHT-HOUSE. is certainly the construction of those guides to the mariners upon rocks which exist in the tracks of ships, or upon dangerous shores and the mouths of harbors. This is not the place to enter largely upon any special description of the lights which are adopted around our shores; a brief account only will be given of some of the more remarkable principles which have been introduced of late years by the Trinity Board. The eaily ligiit-houses appear to have been illumin^ited by coal or wood fires contained in "chauffers." The Isle of Man light was of this kind until 1816. The first decided improvement was made by Argand, in 1784, who invented a lamp with a circular wick, the flame being supplied l)y an external and internal current of air. To make these lamps more effective for light-house illumination, and to prevent the ray of light escaping on all sides, a reflector was added in 1780 by M. Lenoir; this threw the light forward in ]iarallel rays towards such points of the horizon as would be useful to the mariner. Good reflectors increase the luminous effect of a lamp about 400 times; this is the " catoptric" system of lighting. When reflectors are used, there is a certain cjuantity of light lost, and the " dioptric " or refractitu/ system, invented by the late M. Augustin Fresnel in 1822, is designed to obviate this effect to some extent. The " catadioptric " system is a still further improvement, and acts both by refraction and reflection. Lights of the first order have an interior radius or focal distance of 3G'22 inches, and are lighted by a lamp of four concentric wicks, consuming 570 gallons of oil per annum. The appearance of light called short eclipses has hitherto been obtained by the fol- lowing arrangen.ent : — An apparatus for a fixed light being provided, composed of a central cylinder and two zones of catadioptric rings forming a cupola and lower part, a certain number of lenses are arranged at equal distances from each other, placed upon an exterior movable fr.ime making its revolution arouml the apparatus in a given period. These lenses, com- posed of vertical prisms, are of the same altitude as the cylinder, and the radius of their curves is in opposite directions to those of the cylinder, in such a manner that at their passage they converge into a parallel pencil of light, all the diverging raj^s emitted hori- zontally from the cyhnder, producing a brilliant effect, hke that obtained by the use of annular lenses at the revolving light-houses. Before proceeding wit;h the description of the lenses, the following notices may be of interest: — The Eddystone Light-house, 9| miles from the Rame Head, on the coast of Cornwall, was erected of timber by Winstaidey in IG'.tlJ-OS, and was washed away in 17u3. It was rebuilt by Rudyard in 1706, and destroyed by fire in 1755. The present edifice was erected by Smeaton 1757-59. Tallow candles were used in the first instance for the lights; but iu 1807 Argand lamps, with paraboloidal reflectors of silvered copper, were substituted. The Skerry vore Rocks, about 12 miles south-west of Tyree on the coast of Argyle- shire, lying in the track of the shipping of Liverpool and of the Clyde had long been regarded with dread by the mariners frequenting these seas. The extreme difficulty of the position, exposed to the unbroken force of the Atlantic Ocean, had alone deterred the commissioners of northern lights from the attempt to place a light upon this danger- ous spot ; but in 1834 they caused the reef to be surveyed, and in 1838 Mr. Alan Ste- phenson, their engineer, inheriting his f ither's energy and scientific skill, commenced his operations upon a site from which "nothing could be seen for miles around but white foaming breakers, and nothing «ould be heard but the howling of the winds and the lashing of the waves." His design was an adaptation of Smeaton's lower of the Eddy- stone to the peculiar situation, a circumstance with which he had to contend. He estab- lishi'd a circular base 42 feet in diameter, rising in a solid mass of gneiss or granite, but diminishing in diameter to the height of 2(3 feet, and presenting an even concave sur- fiicc all around to the action of the waves. Immediately above this level the walls are 9"58 feet tiiick, diminishing in thickness as the tower rises to its highest elevation, where the walls are reduced to two feet in thickness, and the diameter to 16 feet. The tower is built of granite from the islands of Tyree and Mull, and its height from the base is 138 feet 8 inches. In the intervals left by the thickness of the walls are the stairs, a space for the necessary supply of stores, and a not uncomfortable habitation for three attend- ants. The rest of the establishment, stores, &c., are kept at the depot in the island of Tyree. The light of the Skerryvore is revolving, and is produced by the revolution of eight annular lenses around a central lamp, and belongs to the first order of dioptric lights in the svstem of Fresnel, and may be seen from a vessel's deck at a distance of 18 miles. — Lord De Maule}i, Juror''s Report, Great Exhibition, 1851. Some of the lenticular arrangements must now claim attention. Large lenses, or any large masses of glass, are liable to striaj, which by dispersing, occasion a loss of much light. " In order to improve a solid lens formed of one piece of glass whose section is a, "*) />. I*. F, K, D, c. A, Buffon proposed to cut out all the glass left white in the figure, LIGHT-HOUSE. 717 (411,) namely, the portions between m p and n o, and between n o and the left-hand sur- f'lco of D E. A lens thus constructed would be incomparably superior to a solid one, but .-ujh a process we conceive to be impracticable on a large scale, from the extreme (UfhcuUy of polishing the surfaces a vi, b p,c v, f o, and the left-hand surface of d k ; and even if it were *'l 1 practical the greatest imperfections of the glass might liappen to occur in the parts which are left. In oidcr to remove those imperfections and to construct lenses of any siaic," says Sir David Brew ster, '' I proposed in 1811 to build them up of separate zones or rings, cich of which rings was again to be composed of s.'parate segments, as shown in the front view of the lens in fg. 412. This lens is composed of one cen- tral lens A B c D, corresponding with its section n e, in fg. 412; of a middle ring g e l i, corresponding to c D E F, and consisting of 4 segments ; and another ring N p R T, corresponding to a c f b, and consisting of 8 segments. The preceding construction obviously puts it in our power to execute those lenses to which I have given the name of pol>/zona' lenses, of pure flint glass free from veins; but it possesses another great advantage, namely, that of enabling us to correct very nearly the spherical aberra- tion by maUiiig the foci of each zone to coincide." — Brewster. This description will enable the reader to understand the system which has been adopted by Fresnel and carried out by the French government, and by our own commis- sioners of lights. In the fixed dioptric light of Fresnel, the flame is placed in the centre of the appa- ratus, and within a cylindric reflector of glass, of a vertical refracting power, the breadth and height of a strip of light emitted by it beinoj dependent upon the size of the flame and the heiglu of the reflector itself; above and below is placed a series of reflecting prismatic rings or zones for collecting the upper and lower diverging rays, which, falling upon the inner side of the zone, are refracted, pass through the second side, where they suffer total reflection, and, passing out on the outer side of the zone, are again refracted. The effect of these zones is to lengthen the vertical strip of light, the size of which is dependent upon the breadth of the flame and the height of the apparatus. In Fresnel's revolving light-house, a large flame is placed in the centre of a revolving frame which carries a number of lenses on a large scale and of various curvatures, for the avoidance of spherical aberration. With the view of collecting the diverging rays above the flame, an arrangement of lenses and silvered mirrors is placed immediately over it. By this compound arrangement, the simply revolving character of the apparatus is de- stroyed, as, in addition to the revolving flash, a vertical and fixed light is at all times seen, added to which agri>at loss of light must be sustained by the loss of metallic reflect- ors. In 1851, Messrs. Wilkiiis and Letourneau exhibited a catadioptric apparatus of great utility. It was thus described by the exhibitors: — The first improvement has special reference to the light, and produces a considerable increase in its power, whilst the simplicity of the optical arrangements is also regarded. It consists, firstly, in completely dispensing with the movable central cylindrical lenses; secondly, it replaces these by a single revolving cylinder composed of four annular lenses and four lenses of a fixed light introduced between them ; but the iniml)er of each vary- ing according to the succession of flashes to be produced in the period of revolution. The second improvement, of which already some applications tliat have been made serve to show tlie importance, consists in a new method of arranging the revolving parts, experi(.'nce having shown that the arrangennmts at present in use are very faidty. A short time is sufficient for tlio action of the friction rollers, revolving on two paralhd planes, to produce by a succession of cuttings a sufficiently deep groove to destroy the regularity of the rotary movement. To obviate this great inconvenience, the friction rollers are so placed and fitted, on an iron axis with regulating si'rews and traversing between two levelled surfaces, that when an indentation is made in one place they can be adjusted to another part of the plates which is not so worn. The third improvcmuit produces the result of an increase of the power of the flashes in revolving lighthouse apparatus to doul)le what has been obtained hitherto. By means of lenses of vertical prisms placed in the ])rolongation of the central annular lenses, the diverging rays emerging from the catadioptric zone are brought into a straight line, and a coincidence of the three lenses is obtained. The whole of the prisms, lenses, and zones arc mounted with strength artd simplicity, accurately ground and polished to the connect curves according to their respective posi- tions, so as to properly develop this beautiful system of Fresnel. The glass of which they are composed should be of the clearest crystal color, and fiec from that green hue which so materially reduces the power of the light, and is considered objectionable for 718 LIGIIT-nOUSE. apparatus of this kind. Tlie lamp by which the apparatus is to bo lighted consists of a concentric burner with four circular wiclr l)eiuf; separated l)y filtration ami well washed, arc found to dye tlie same colors as those obtained by nii-ans of madder, in fact, these flocks contain alizarine, to which they owe their tinctorial i)()wer, but they also contain a crj'stallized yellow coloring matter, similar to, but not identical with rubia'cine, as well as two resinous coloring matters, which Schunck has named Veranlinc and liu/nirline, and which arc probal^ly identical with the resinous coloring matters before referred to as being obtained from ordinary madder. The li<]uid filtered from the flocks contains an un- crystallizable sugar, similar to that which is obtained from madder itself. Rubian is not decomposed by ordinary ferments, such as yeast and decomposing casein ; but by extract- 732 MADDER. in" madder with cold water, and adding alcohol to the extract, a substance is precipitated in pale red flocks, which possesses in an eminent degi-ee the power of effecting the decom- position of rubian. It a watery solution of the latter be mixed with some of the flocculent precipitate, (after having been collected on a filter, and washed with alcohol,) and then left to stand in a warm place for some hours, the mixture is converted into a light brown jelly, which is so thick that the vessel may be reversed without its falling out. This jelly, when agitated with cold water, communicates to the latter very little color or taste, proving that the rubian has undergone com{)lete decomposition by the action of the flocculent substance or ferment added to its solution. The cold water, however, extracts from the gelatinous mass a quantity of sugar, Avhile the portion left undissolved contains alizarine, verantinc, rubiretine, and a crystalline yellow coloring matter, besides a portion of undecomposed fer- ment. Rubian, therefore, by the action of strong mineral acids and of the peculiar ferment of madder, is decomposed, yielding sugar and a variety of coloring matters, the principal of wiiich is alizarine. It appears, therefore, that these coloring matters are not originally contained as such in the root, but are formed by the decomposition of one parent substance, which alone is produced by the vital energies of the plant. In addition to this substance, the plant also contains another, which possesses the projicrty of rapidly effecting the de- composition of the first. The two are, however, during the living state of the plant, pre- vented from acting on one another, either in consequence of their being contained in diifer- ent cells, or because the vital energies of the plant resist the process of decomposition. During the drying and grinding of the root, the decomposition of the color-producing body commences, and continues slowly during the period that the powder is kept before being used. It is finally completed during the process of dyeing itself, and hence no trace of color-producing substance can be detected, either in the liquor or the residual madder, after the operation of dyeing is concluded. The presence of oxygen does not seem to be essen- tial during this process of decomposition, as Decaisnc supposed. Nevertheless, according to Schunck, rubian does in reality suffer a partial oxidation, when its watery solution, mixed with some alkali or alkaline earth, is exposed to the action of the atmosphere, giving rise to a peculiar acid, called by him rtthianic acid. When rubian is heated at a temperature considerably exceeding 212" F., it is converted without much change of appearance into a substance which yields by decomposition resinous coloring matters in the place of alizarine. The great excess of these coloring matters contained in the madder of commerce arises therefore most probably from the high temperature employed in drying the root. Emploiiment of Madder in Di/ei/ir/. — After the account which has just been given of the composition of madder, it may easily be conceived that the chemical and physical phe- nomena which occur during the various processes of madder dyeing, are of a rather com- plicated nature, and that many of these phenomena have not yet received a perfectly satis- factory explanation. Nevertheless, the present state of our knowledge on this subject may enable us to give a consistent explanation of the facts presented to us by the experience of the dyer, and even to indicate what direction our labors must take if we wish to improve this branch of the arts. In order to produce perfectly f;ist colors in madder dyeing, it is necessary that the mad- der should contain a large proportion of carbonate of lime, and if the madder is naturally deficient in that salt, the deficiency may be supplied either by using calcareous water in dyeing, or by adding a quantity of ground chalk. If madder be treated with dilute sul- phuric or muriatic acid, so as to dissolve all the lime contained in it, and then washed with cold water until the excess of acid is removed, its tinctorial power will he found to be very much diminished, but may be entirely restored, and even increased, by the addition of a proper quantity of lime-water or chalk. Hence, too, Avignon madder, which is grown in a highly calcareous soil, and contains so much carbonate of lime as to effervesce with acids, affords the most permanent colors ; whilst Alsace madder requires the addition of car- bonate of lime in order to produce the same effect. This fact was first pointed out by riausmann, who, after having produced very fine reds at Rouen, encountered the greatest obstacles in dyeing the same reds at Logelbaeh, near Colniar, wliere he went to live. Nu- merous trials," undertaken with the view of obtaining the same success in his new establish- ment, proved that the cause of his favorable results at Rouen existed in the water, which contained carbonate of liuie in solution, whilst the water of Logelbaeh was nearly pure. lie then tried a factitious calcareous water, by adding chalk to his dye-bath. Having ob- tained the most satisfactory results, he was not long in producing here as beautiful and as solid reds as he had done at Rouen. This simple fact led to the production of a series of lengthy memoirs on the part of some of the French chemists and calico-printers; which fully confirmed the results of Hausmann, without, however, leading to a satisfactory expla- nation of them. The experiments of Robiquet prove that in dyeing with pure alizarine the least addition of lime is rather injurious than otherwise, as it merely weakens the colors without adding to their durability. Hence, the beneficial effect of lime can only be ac- counted for by some action which it exerts on other constituents of the root. Bartholdi imagined that this action consisted simply in the decomposition of the sulphate of magne- I MADDER. 733 sia, which he found to be contained in ordinary madder. It was asserted by others, that the carbonate of lime served to neutralize some free acid, supposed by Kuhlmann to be malic acid, which was present in some madders, and which not only to a great degree pre- vented the coloring matters from dissolving in the dye-bath, but also combined with the mordants to the exclusion of the latter. Though later researches have failed to detect the existence of malic acid in madder, still it is certain that all watery extracts of madder con- tain pectic acid, which probably exists in the root originally as pectine ; and that this acid, when in a free state, acts most injuriously in dyeing with alizarine, but ceases to do so as soon as it is combined with lime. Nevertheless, it seems that madder which is naturally deficient in lime, cannot be made to replace entirely such madder as has been grown in a calcareous soil, however great an excess of chalk be used in dyeing. Hence Robiquet was led to the conclusion, that the inferior kinds of madder, which are also the most deficient in lime, contain more purpurine and less alizarine than the superior kinds, and that the car- bonate of lime serves partly to combine with the purpurine and prevent it from uniting with the mordants, and thus producing less permanent dyes. The experiments of Schunck have proved that not only pectic acid, but also rubiacine and the resinous coloring matters of madder, act detrimentally in dyeing with pure alizarine, by deteriorating the colors and sullying the white parts of the fabric, and that these "effects are entirely neutralized by the addition of a little lime-water to the dye-bath. If in dyeing with madder the whole of the coloring matters were in a free state, the resinous and yellow coloring matters would, ac- cording to Schunck, unite with the mordants, to the exclusion of the alizarine, yielding colors of little permanency and of a disagreeable hue ; but on adding lime tliey combine with it, and the alizarine, being less electro-negative, then attaches itself to the mordants or weaker bases. A great excess of lime would of course have an injurious effect by combin- ing also with the alizarine, and preventing it from exerting its tinctorial power. In prac- tice, a little less lime is added than is sufficient to take up the whole of the impurities with which the alizarine is associated, thus allowing a portion of the former to go to the mor- dants, to be subsequently removed by treatment with soap and other detergents. Lastly, it has been asserted by Kochlin and Persoz, that when lime is used in dyeing with madder, the colors produced are not simply compounds of coloring matter with mordants, but con- tain also in chemical combination a certain quantity of lime, which adds very much to their stability. It is probable that all these causes contribute in producing the effect. The car- bonates of magnesia and zinc, acetate and neutral pliosphate of lime, and the protoxides of leal, zinc and manganese, act in a similar manner to carbonate of lime in madder dyeing, but are less efficient. Damboarney and Beckman have asserted, that it is more advantageous to employ the fresh root of midder than that which has been submitted to desiccation, especially by means of stoves. But in its state of freshness, its volume becomes troublesome in the dj'e-batli, and uniform observation seems to prove that it ameliorates by age up to a certain point. Besides, it must be rendered susceptible of keeping and carrying easily. In dyeing printed calicoes with madder, the general course of proceeding is as follows : — The midder having been mixed in the dye-vessel with the proper quantity of water, and, if necesj-ary, with chalk, the liquid is heated slowly by means of fire or steam, and the fabric is introduced and kept constantly moving, until the dyeing is finished. The tempera- ture should be kept low at first, and should be gradHally raised, without allowing it to fall, until it reaches the boiling-point ; and the boiling may, if necessary, be continued for a short time. The chief object of the gradual heating seems to be to allow the ferment to exert its full power on the rubian or color-producing body, for this process, like all pro- cesses of fermentation, is most active at a temperature of about 100^ F., and is arrested at 212' F. In dyeing quickly, less permanent colors are also produced, in consequence, prob- ably, of the coloring matters combining with the more superficial portions of the mordants, and not penetrating sufficiently into the interior of the vegetable fibre. The fiistest colors are produced by dyeing at a moderate temperature, and not allowing the liquid to boil. By boiling, the madder becomes more thoroughly exhausted, and a greater depth of color is attained, but the latter resists less perfectly the action of soap and other agents, than the same shade dyed at a lower temperature. The time occupied in dyeing varies according to the nature and intensity of the colors to be produced ; but there is little advantage in allowing it in any case to exceed three hours, since the gain in color acquired is more tlian counterbalanced by the loss of time and increased expenditure of fuel caused by a long- continued ebullition. In dyeing ordinary madder coloi-s, such as red, black, chocolate, and common purple, which do not require much treatment after dyeing, in order to give them the desired tone and intensity, strong but inferior qualities of madder may be used with advantage ; and various other dye-stuffs, such as peachwood, quercitron bark, sumac, &c., are often added to the madder, in order to vary the shade and depth of color. But for the finer colors, such as pink and fine purple, whicli after dyeing must be subjected to a long course of treatment with soap and aciils btfore they assume the requisite beauty and deli- cacy of hue, it is necessary to employ the finest qualities of madder ; for if dyed with infe- 734 MADDER. rior qualities they would resist only imperfectly the requisite after-treatment, and great care must be observed in regulating the temperature during dyeing. The addition of other dve- stuffs, in their case, would be not only useless, but positively injurious. The use of dift'er- ent kinds and real quantity of coloring matter in the root, and of determining the comparative value of different samples of madder, led to many attempts on the part of chemists to improve the quality of this dye-stuff" by means of chemical agents, and thus render it more fit for the purjioses to wliich it is applied. Kobiijuet and I'ersoz were the first to point out the advantages which result from submit- ting madder, previous to its being used, to the action of strong acids. They showed that, by acting on madder with strong sulphuric acid, and then carefully washing out the acid with Water, a product was obtained, wiiich not only possessed a greater tinctorial power than the original material, but also dyed much brighter colors. This iniiiortant discovery, which was not, like so many others, arrived at by chance, but was purely the result of scientific investigation, did not at first receive, on the part of practical men, the appreciation which it deserved. The product obtained by the action of sul[)liuric acid on madiler, wliich in the first instance was called rhnrhon sa/furiqur^ afterwards r/n-es. To guard against misapprehension, we would observe that, in one sense, all the fertiliz- ing agents are alike valuable ; for they are all indispensai)le for the healthy condition of our cultivated crops, and, consequently, the absence of one is attended with seiious I'oiiseciuences, though all others may be present in abmulaiu'e. Thus the deficiency of lime in the land is attended with as much injury to the plant iw that of |)h()sphoric acid. In this sense lime is as valuable a.s ])hosphoric acid ; but ina.smuch as lime is generally found in most soils in abundant (|tiantilie.s, or, if deficient, can be applied to the land economically in the form of slackeil lim(>, marl, shell sand, &c., its presence in an artificial manure is by no means a recommendation to it. The principal constituents of Manures arc : — Y40 MANURE, ARTIFICIAL. 1. Nitrogen (in the shape of ammonia, nitric acid, and nitrogenized organic matters.) 2. Phosphoric acid (bone-earth and soluble phosphates.) 3. Potash (carbonate and silicate of potash.) 4. Soda (common salt.) 5. Lime and magnesia (carbonate and sulphate of lime and magnesia.) 6. Soluble silica. 7. Humus, forming organic matters (vegetable remains of all kinds.) 8. Sulphuric acid (sulphate of lime.) 9. Chlorine (common salt.) 10. Oxide of iron, alumina, silica (clay, earth, and sand.) AVe have here mentioned these constituents in the order which expresses their compara- tive commercial value. 1. Nitrogen. — This element may be incorporated with artificial manures in the shape of ammoniacal salts or nitrates, or nitrogenized organic matters. The cheapest ammoniacal salt is sulphate of ammonia ; the cheapest nitrate is Chili salt- petre, or nitrate of soda ; hence sulphate of ammonia and nitrate of soda are exclusively employed by manure manufacturers for the preparation of nitrogenized manures, when no organic refuse matters containing nitrogen, such as horn-shavings, bone-dust, woollen rags, blood, glue refuse, &c., are availiable. Nitrogen in any of these forms exercises a most powerful action in manure, especially when applied to plants at an early stage of their growth ; at a later period of development the application of ammoniacal salts or nitrate of soda appears much less effective, and some- times even useless. For this reason nitrogenized manures, such as guano, soot, specially prepared wheat manures, &c., ought to be applied either in autumn or in spring, immediate- ly after the young blade has made its appearance above ground. Ammoniacal salts, nitrate of soda, and decomposed nitrogenized organic matters have a most marked effect upon the leaves of plants, they induce a rapid and luxuriant develop- ment of leaves, and may therefore be called leaf-producing or forcing manures. Grass, wheat, oats, and other cereals, when grown upon soils containing abundance of available mineral elements, are strikingly benefited by a nitrogenized manure ; but, on account of their special action, they ought to be used with caution in the case of corn-crops, and always more sparingly on light than on heavy land ; otherwise, fine straw, but little and an inferior sample of grain, will be obtained. As a general rule, ammoniacal salts or nitrate of soda should not be used by farmers in a concentrated state, and exceptionally only. However useful sulphate of ammonia or nitrate of soda may be in a particular case, it ought to be remembered that generally such manures produce beneficial effects only in conjunction with mineral matters. If, there- fore, a proper amount of available mineral substances does not exist in the soil, it has to be supplied in the manure. Ammoniacal salts, nitrate of soda, animal matters, &c., are therefore almost always blended together with phosphates, common salt, gypsum, &c., by manufacturers of manures. Whilst we thus fully recognize the importance of the presence of ammonia, ammoniacal salts, nitrates, or animal matters furnishing ammonia on decomposition in manures, especial- ly in manures for white crops, we cannot agree with those who estimate the entire value of manuring substances by the proportion of nitrogen which they contain. In a purely commercial sense, nitrogen in the shape of ammonia or nitric acid, or animal nitrogenized matters, is the most valuable fertilizing constituent, for it fetches a higher price in the market than any other manuring constituent. 2. Phosphoric acid. — Next in importance follows phosphoric acid. This acid exists largely in the grain of wheat, oats, barley, in leguminous seeds, likewise in turnips, man- golds, carrots, in clover, meadow-hay, and, in short, in every kind of agricultural produce. Whether we grow, therefore, a cereal crop or a fallow crop, there must be phosphoric acid in sufficient quantity in the soil, or if insufficient it must be added to the land in the shape of manure. The proportion of phosphoric acid in even good soils is very small, and as the agri- cultural produce in almost every case removes from the soil more of phosphoric acid than of any other soil-constituent, the want of available phosphoric acid makes itself known very soon. This is especially the case with quick-growing crops, such as turnips, mangolds, &c. The whole period of vegetation of these green crops extends only over four or five months, and the fibrous roots of these crops are unable to penetrate like wheat the soil to any con- siderable depth. For these reasons phosphoric acid in some form or other has to be abundantly supplied to root-crops ; and experience has shown that no description of fertiliz- ing matter benefits .so much roots as super-])hosphate and similiar manures, which contain phosphate of lime in a state in which it is readily a.«similated by plants. In artificial manures, phosphoric acid commonly occurs in the shape of bone-dust, boiled bones, bone-shaving (refuse of knife-handle makers, turners of ivory, button-makers, &c.,) or in the state of bi-phosphate of lime, purposely manufactured from bone-materials or from phosphatic minerals. MANURE, ARTIFICIAL. 741 The phosphate of lime which occurs in fresh bone, practically speaking, is insoluble in water. In water charged with carbonic acid, and still more so in water containing some ammonia, it is more soluble than in pure water. On fermenting bone-dust in heaps, it be- comes a much more effective manure. Such fermented bone-dust is added with much benefit to general artificial manures. All really good artificial manures should contain a fair proportion of phosphate — say from 25 to 40 per cent., according to the uses for which the manure is intended. General- ly speaking, manures for turnips, and root-crops in general, should be rich in phosphates, especially soluble phosphates, (bi-phosphate of lime ;) such manures need not contain more than I to li per cent, of ammonia, and, when used on land in a tolerably good agricultural condition, ammonia can l)e altogether omitted in the manure without fear of deteriorating the efficacy of the manure. 3. Potash. — Salts of potash unquestionably are valuable fertilizing constituents, for potash enters largely into the composition of the ashes of all crops. Root-crops especially require much potash ; hence these crops are much benefited by wood ashes, burnt clay, liquid manure, and other fertilizers containing much potash. The commercial resources of potash are limited, and salts of potash without exception far too expensive to be employed largely in the manufacture of artificial manures. Potash consequently is rarely found in artificial manures. Fortunately, potash exists abundantly in most soils containing a fair proportion of clay. Its want in artificial manures therefore is not perceived, at least not in the same degree in which the deficiency of phosphates in a manure would be felt. 4. Soda. — Salts of soda arc much less efficacious fertilizing matters than salts of potash. There are few soils which do not contain naturally enough soda, in one form or the other, to satisfy the wants of the crops which are raised upon them. However, common salt is largely employed in the manufacture of artificial manures ; if it does no good, it certainly does no harm, and in this «ountry is one of the cheapest diluents which can be employed for reducing the expenses of concentrated fertilizing mixtures to a price at which they can be sold to farmers. In Continental districts common salt proves more efficacious as a manure than in England, where the neighborhood of the sea provides the majority of soils with plenty of salt, which by the winds is carried landwards with the spray of the sea to very considerable distances. Salt, however, even in England, is usefully applied to mangolds, and enters largely into the composition of most artificial manures expressly prepared for this crop. 5. Lime and Magnesia. — All plants require lime and magnesia in smaller or larger quantities. Many soils contain lime in superabundance ; in otiiers it is deficient. To the latter soils it must be added. This can be done by lime-compost, by slaked lime, by marl, shell-sand, or gypsum. All these calcareous manures are cheap almost everywhere, for lime and magnesia are among the most widely distributed, and most abundant mineral substances. The addition of chalk, marl, and even gypsum, to artificial manures, should therefore be avoided as much as possible. At the best, carbonate and sulphate of lime in artificial manures must be regarded as diluents. 6. Soluble Silica The artificial supply of soluble silica to the land, as far as our present experience goes, has done no good whatever to cereals, the straw of which soluble silica is supposed to strengthen. In the absence of reliable practical experiments with soluble silica, we cannot venture to recommend the use of silicate of soda, or soluble silica to manure manufacturers. 7. Organic substances, Humus — The importance of organic matters free from nitrogen, as fertilizing agents, is very trifling. Formerly the value of a manure was estimated by the amount of organic matter it contained, and little or no difierence was made whether the organic matter contained nitrogen or not. Under good cultivation, the organic matter in the soil regularly increases from year to year ; there exists therefore no necessity of supplying it in the shape of manure. In artificial manures we should certainly exclude all substances that merely add to the bulk, without enhancing the real fertilizing value of the manure. Peat, saw-dust, and similar organic matters, &c., are useful to the manure-maker only as diluents and absorb- ents of moisture. 8. Sulphuric acid is another constituent of manure, which possesses little value. In artificial manures sulphuric acid chiefly occurs as gypsum. 9. Chlorine exists in manures principally as salt. 10. Oxitlc of iron, Alumina, Silica. — These constituents exist sometimes in manures in the shape of burnt-clay, earth, brick-dust, and sand. It is hardly necessary to remark that good artificial manures should contain as little as possible of tiiese mattei-s. It will api)ear from the preceding observations, that nitrogen in the shape of ammonia- cal salts, nitiic acid or decomposed animal matters, and phosphoric acid are the most valuable fortili/.ing constituents. 742 MANUKE, ARTIFICIAL. The maniifiicturers of artificial manures should therefore endeavor: 1. To jjroduce manures containing as little water as possible. 2. To incorporate as much of nitrogenized organic matters, or ammoniacal salts, ot nitrates and phosphates, in general manuring mixtures, as is possible at the price at which artificial manures are usually sold. 3. To avoid as much as possible, gypsum, salt, peat-mould, chalk, and other substances that chiefly add to the bulk, without increasing the efficacy, of the manures. He should also endeavor to produce uniform finely pulverized articles, that run readily through the manure drill. It likewise devolves on the manufacturer of manures to render more effective, that is to s;iy, more rapid and energetic in their action, refuse materials which may remain inactive in the soil for years before they enter into decomposition, and to reduce by chemical means into a more convenient state for assimilation, raw materials, which like coprolites, apatite, &.C., produce little or no beneficial effects upon vegetation, even when added to the land in a finely powdered condition. At the present time, two classes of artificial manures may be distinguished : 1, general maiHires, i. e. manures which profess to .suit equally well every kind of agricultural pro- duce ; and 2, specially prepared for a particular crop only. The requirements of different crops, or perhaps, more correctly speaking, the conditions that legulate the a.ssimilation of food, vary so much, that we doubt the policy of manure- makers to prepare general artificial manures. At the same time, we doubt the necessity of preparing artificial manures for eveiy description of crop. Special manures are extreme- ly useful to faimers, if they are prepared by intelligent manufacturers, who possess suf- ficient chemical knowledge to take advantage of every improvement that is made in manufacturing chemistry, and at the same time know sufficient of agriculture to understand what is really wanted in a soil. In other words, except a manufacturer is a good practical chemist, and a tolerably good farmer, he will not be able properly to adapt the compo.sition of special fertilizers to the nature of the soil, and the peculiar mode of treatment which the land lias received on the part of the farmer. However, nearly all special artificial manincs, generally speaking, may be arranged under two heads. They are either: I. Nitrogenized Manures, or, 2. Phosphatic Manures. The first may l)e used with almost equal advantage for wheat, barley, oats, for rye, and on good land likewise for grass. The second are chiefly used for root-crops. Nitrogenized artificial manures frequently are nothing more than guano, diluted with gypsum, salt, peat-mould, earth, &c. In fact, guano is the cheapest ammoniacal manure, for which reason it is so largely employed for compounding low-priced wheat manures, grass manures, &c., &c. Good manures for cereals may be made by blending together fine bone-dust, or bone- dust dissolved in sulphuric acid, sulphate of ammonia, salt and gypsum. These manures will be the better the more sulphate of ammonia they contain. Turnip-manures, and artificial manures for root-crops in general, consist principally of dissolved bones, or dissolved coprolites and other mineral phosphates. They are, in fact, superphosphates of various degrees of concentration. The more soluble phosphate a root- manure contains, the better it is adapted to the purpose for which it is used. Most samples of superphosphate contain little or no ammonia, or nitrogenized organic matters. Others sold under the name of nitro- or ammonia-phosphate, in addition to soluble and insoluble pliosphate, contain some ammonia and organic matters. Blood manure is a superpiiosphate, in the pi-eparation of which some blood is used. In preparing superphosphate from bones, it is essential that they should be reduced to fine dust. Tiiis is moistened with about i^ its weight of water, after which another third to one-half of brown sulphmic acid is added. The pasty mass is allowed to cool, in the mix- ing vessel, or when large (|uantities ai'c i)rc|)arcd, the semi-liquid mass in the mixer is lun out still hot, fresh (piantities of Ixuie-dust, water, and acid are put in the mixer, and after 5 or lt> minutes the contents allowed to run out, and a fresh quantity prepared as before. The successive mixings are all kept together in one heap for 1 or 2 months ; the heap is then turned over and, if necessary, the partially di.ssolved bones tire pa.s.sed through a riddle. In a similar manner, coprolites, bone-a.sh, apatite aiul other jjhosphatic minerals are treated with acid. It ought to be observed, however, that the (|uantity of liiown sulphuric acid necessary fb collected, whilst another charge is being placed in the furnace. About 7 cwt. or 8 cwt. of ore is the quantity usually roasted at one METALLURGY. 745 time. Whilst undergoing this operation, dense fumes of arsenic and sulphur escape with the smoke from the fire, and pass through large flues, divided into several chambers, {fig. 420 422,) where the former is collected. The flue is often 70 yards long, and the greatest de- posit of arsenic takes place at about 15 yards from the oven or furnace. Instead of being 422 at once completely roasted, the "whits" from the stamps are sometimes first "rag" (or partially) burnt, for al)out six or eight hours. The object of this partial burning is to save 746 METALLUKGY. time and expense, nearly three-fourths of it being thrown away after dressing it from the first burning. Fig. 423. The machine called originally "Brunton's Patent Calciner," for calcining tin 423 ore, is gradually coming into use in Cornwall, ana is adopted in many of the larger mines. Its operation m'ay be thus briefly described :— A revolving circular tabic, usually 8 feet, or 10 feet in diameter, turned by a water-wheel, receives through the hopper the tin stuff to be roasted or calcined. The frame of the table is made of cast-iron, with bands, or rings, of wrought iron, on which rests the fire-bricks composing the surface of the table. The flames from each of the two fireplaces pass over the ore as it lies on the table, which slowly revolves, at the rate of about once in every quarter of an hour. In the top of the dome, over the table, are fixed three cast-iron frames called the " spider," from which depend nu- merous iron coulters, or teeth, which stir up the tin stuff, as it is carried round under them. The coulters on one of the arms of the "spider" are fixed obliquely, so as to turn the ore downwards from one to the other— the last one at the circumference of the table, project- ing the ore (by this time fully calcined) over the edge, into one of the two " wrinkles " l)e- neath. A simple apparatus called the " butterfly," moved by a handle outside the building, diverts the stream of roasted tin stuff, as it falls "from the table, either into one or the other, METER, GAS. 747 as may be required. Unlike the operation of roasting in the oven previously described, the calciner requires little or no attention ; the only care requisite being to see that the hopper is fully supplied, and the roasted ore removed when necessary from the wrinkles. For this description of the burnin;^ house and of the calciner, we are indebted to Mr. James Henderson's communication to the Institution of Civil Engineers. We have been favored with the following notes on the action of Brunton's calciners, employed at Fabriea la Coustauto, Spain, which are of great value, as are also the additional suggestions : — Diameter of revolving bed, 14 feet. Revolution of bed per hour from 3 to 4, or about 1 foot of the circumference per minute. Ores introduced by hopper, at the rate of 1 quintal to every revolution of table. Quantity of ore calcined per day of 10 hours, 30 to 35 quintals. Salt consumed, generally 6 per cent, of weight of ore. Fuel consumed per 10 hours, 1,200 to 1,400 lbs. of pine wood. Power employed to revolve table, half horse. Remarks. — The furnace is charged with ore and salt by means of iron hoppers placed imruediately over the centre of each of the hearths. For the supply of each hopper, a heap of about 14 quintals of ore, with 5 or 6 per cent, of salt, is prepared from time to time upon a small platform on the top of the furnaces, and a few shovelfuls thrown in occa- sionally as required, taking care, however, always to have enough ore in the hopper to pre- vent the ascension of acid vapors, &c., from the furnace. The time the mineral remains in the furnace, and the quantity calcined per hour, must depend on the rapidity of motion of the revolving hearth, and the angle at which the iron stirrers are fixed. The average amount passed through each furnace in 24 hours is about 84 quintals, or 3i quintals per hour. For every revolution of the bed, nearly 1 quintal is discharged I'rom the furnace. Compared with the German Rostofen, the mechanical furnaces are less efficient for the calcination of silver ores, particularly when the ores operated on are very damp, and con- tain much sulphur ; in which case the excessive production of lumps becomes a serious in- convenience to contend with. But in the treatment of the silver ores of Steindelencira, they possess the advantage of calcining a large quantity of ore in a given time, and require no further attendance than is necessary for supplying them with ore and fuel. The supply of fuel is, however, subject to great neglect. Tiie management of the fires is nevertheless a matter of much importance, for should they be forgotten, and the heat get much reduced, the mineral, from continuing to pass at the same rate through the furnace, cannot be properly calcined. To prevent the fires getting low, and to raise them after being neglected, the workmen often load the grate with fuel, tlie result of which is to overheat the ore and cause a great waste of wood. Some measure is evidently necessary to regulate the supply of fuel to the grate. The most simple appears to be an alarum that shall be rung, for example, at every revo- lution of the hearth, so as to call the attention of the men to tlie fires ; and then not more than a given quantity of wood should be thrown on the grate, which, repeated at every turn made by the bed, or once in a quarter of an hour, would sustain a nearly constant tem- perature in the furnace. See Silver. METER, GAS. The most recently constructed meters on the dry principle are those of Defries, and of Messrs. CroU & Richards. Both of these contrivances consist in causing the gas to fill expansible chambers of definite volume, and the alternate expansion and con- traction of these is registered l)y wheel-work. Defries' meter has three of tiiese measuring chambers, separated from each other by flexible leather partitions which are partly covered by metallic plates, to protect them from the action of the gas. a a a a, {fig. 424,) represent these metallic plates fixed upon the leather diaphragm b d b b. As the gas enters, it causes the flexible partition to expand, which it does by a.ssuming the form of a cone, as seen in fg. 425. Three such chambers are attached to each meter, so as to insure a uniform and steady supply of gas, and the motion of the chambers being communicated to clockwork, the consumption of gas is regis- tered upon dials in the usual manner. The dry meter invented by Messrs. Croll & Richards is superior in construction and accuracy of measurement to that of Defries. It is shown in figs. 42('), 427, and 428. a a, {fig. 42t),) is a cylindrical case divided into two cylindrical compartments l)y the inflexible metallic diaphragm n. These compartments are closed at opposite ends by the metal discs c c. The latter perform the functions of pistons, and arc retained in their proper position by universal joints attached to each. The discs are restrained from moving through more than a fixed space by metalHc arms and rods, shown in fig. 427, and wlien this .«;pace has been once adjusted it cannot afterwards vary. It will be seen that the principle of this meter is that of a piston moving in a cylinder ; but, in order to avoid the friction which 748 METER, GAS. such an arrangement would cause if literally carried out, bands of leather, d d, are attached, which act as hinges, and allow of the motion of the discs without friction. 424 425 The gas enters the cylinder from the upper space containing the levers, valves, &c., {jig. 428 ;) its pressure forces the discs forward through the space limited, as above described. METKA. 749 The flow of gas is then reversed ; that is, a passage to the bumere is opened from the inter- nal space, whilst the supply is now directed into the outer chamber, thus forcing the disc back to its original position and expelling the first portion of gas through the pipes of dis- tribution. Each motion of the disc thus evidently corresponds to a given volume of gas, and, being registered by clockwork, indicates the consumption upon the usual dial plates. Dry gas-meters have of late years come into vei-y extensive use, especially in the me- tropolis. — E. F. METRA. This pocket instrument, constructed by the late Mr. Herbert Mackworth — one of H. M. Inspectors of Collieries, — enables the traveller or engineer to take, with con- siderable accuracy, most of those measurements which it is useful to record, and to make use of opportunities which would otherwise be lost. In a brass case, less than three inches square and an inch thick, are contained a clinometer, thermometer, goniometer, level, mag- nifying lens, measure for wire gauze, plummet, platina scales of various kinds, and an ane- mometer. Tiie traveller can ascertain by its means the temperature, the force of the wind, the latitude, the position of the rocks, or survey and map his route. The geologist can de- termine and draw the direction and amount of dip of the rocks, the angles of cleavage and crystallization, the temperature of springs, or examine by a plate of tourmaline the bottoms of pools or shallow depths along coast lines otherwise invisible to the eye. The miner can survey and level the roof or floor of his workings, and requires only a pencil to map them upon paper. He can ascertain the temperature of the air under ground, discover whether the ventilation is deficient, or see whether the wires of his Davy lamp are in safe condition. Figs. 429, 430 represent the plan and side view of the "metra" when open and ready for use. A is the double compass, and b the level. The arc of the level is graduated in 429 degrees, and in inches fall per yard, c the sights ; d the scales ; e the goniometer ; e' the goniometer scale ; f the plummet ; g the lens, witli a telesc()!)ic slide underneath to meas- ure wire gauze ; ii the tourmaline ; j the pivots on which the instrument stands ; k are the two joints of the brass leg, by which the horizontality of the instrument can be obtained ; 750 MINERAL CANDLES. L is a flai chisel point for entering joints of rocks or masonry. This end unscrews, expos- ing a wood-screw, (shown by the dotted lines m,) by which the leg can be secured to a tree or stand ; N is the tliermometer, which, like the compass and level, will read correctly to half a degree ; o is the screw which holds the top and bottom of the instrument together when they are opened out for use, as in the drawing. Beneath the bottom cover p are placed the anemometer, which consists of a thin sheet of transparent mica suspended by pieces of silk, and underneath the mica is a table of " constants,' giving the weights of gases, liquids, and solids, besides some thirty measures .and formulae for steam, boilers, en- gines, ropes, air, &c. The brass leg is seldom of use, and may be dispensed with. By resting the under edge of the side e k' on a bed of rock, and turning the instrument till the bubble comes in the middle of the level, the direction of the " strike " or " level course " of the rock will be ascertained instrumentally. k e' ofiers a long line to measure the amount of inclination with. To lay down surveys on paper, a line should be ruled, and the edge E e' liiid to it. The paper should then be moved until the ruled line comes exactly north and south, when it can be weighted down. The survey is then made by the compass, and the ecales on the paper, just as it had been made on the ground, without the usual cal- culation and ruling of parallel lines. A simpler form is made in wood as a clinometer, con- taining only the compass, level, magnifying glass, and thermometer for the use of geolo- gists. MINERAL CANDLES. These candles and other products (liquid hydro-carbons) are manufactured by Price's Candle Company, at Belmont and Sherwood, according to processes patented by Mr. Warren De la Rue. The novelty of these substances consists — 1. In the material from which they are obtained. 2. In the method by which they are elaborated. 3. In their chemical constitution. The rail] material is a semi-fluid naphtha, drawn up from wells sunk in the neighborhood of the river Irrawaddy, in the Burmese empire. The geological characteristics of the local- ity are sandstone and blue clay. In its raw condition the substance is used by the natives as a lamp-fuel, as a preservative of timber against insects, and as a medicine. Being in part volatile at common temperatures, this naphtha is imported in hermetically closed metal- lic tanks, to prevent the loss of any constituent. Reichenbach, Christison, Gregory, Reece, Young, Wiesman, (of Bonn,) and others, have obtained from peat, coal, and other organic minerals, solids and liquids bearing some physical resemblance to those procured from the Burmese naphtha ; but the first-named products have, in every instance, been formed by the decomposition of their contemporaries attributed the talent of these celebrated artists to a paction which one or the other of them had made with the devil. In the Gobelin and Beauvais Tapestry we have examples of the most artistic productions, executed with a mechanical skill of the highest order, when we consider the material in which the work is executed. The method of nmnufacture involving artistic power on the part of the workman, great manipulatory skill, and the expenditure of much time, neces- sarily removes those productions from tlie reach of any but the wealthy. Various attempts have been made, from time to time, to produce a textile fabric which should equal those tapestries in beauty, and which should be sold to the public at much lower prices. None of those appear to have been successful until the increasing applications of India-rubber pointed to a plan by which high artistic excellence might be combined with moderate cost. In Berlin, and subsequently in Paris, plans — in most i-espects similar to the plan we are about to describe — were tried, but in neither instance with complete success. Of course, there cannot now be many of our readers who have not been attracted by the very life-like representations of lions and dogs which have for the last few years been exhibited in the carpet warehouses of the metropolis, and other large cities. While we admit the perfection of the manufacture, we are compelled to remark that the designs which have been chosen are not such as appear to us to be quite appropriate, when we consider the purposes for which a rug is intended. Doubtless from their very attractive character, and moderate cost, those rugs find a large number of purchasers, by whom they are doubtless greatly ad- mired. It will, however, be obvious to our readers, that they are not consistent with the principles of design, and that there is a want of consistency in the idea of treading u])on the " monarch of the forest," copied with that remarkable life-likeness which distinguishes the productions of Sir Edwin Landsecr ; or in placing one's feet in the midst of dogs or of poultry, when the resemblances are sufficiently striking to impress you with the idea that the dogs will bark, and that the cock will crow. We believe that less picturesque subjects, in accordance with the law — which we conceive to be the true one — which gives true beauty only to that which is, in its applications, consistent and harmonious, would be yet greater favorities than those rugs now manufactured by the Messrs. Crossleys. And amid.st the amount of good which these excellent men are doing to all who come within their in- MOSAIC WOOL WORK. 777 fluence, we are certain they might, with the means at their command, introduce an arrange- ment ot" colors which might delight by their harmonious blending, and a system of designs which, pure and consistent, should ever charm the eye, without attempting to deceive either it or any of the senses. Every attempt to advance the taste of a people is worthy of all honor ; and having the power, as the manufocturers of the mosaic rugs have, of producing worlvs of the highest artistic excellence, we should be rejoiced to see them em- ploying that power to cultivate amongst all classes a correct perception of the true and the beautiful. With these remarks we proceed to a description of the manufacture. Every lady who has devoted herself for a season, when it was the fashion to do so, to Berlin wool-work, will appreciate the importance of a careful arrangement of all the colored woi-steds which are to be used in the composition of her design. Here, where many hundreds of colors, combinations of colors, and shades are required, in great quantities and in long lengths, the utmost order is necessary ; and the system adopted in this establish- ment is in this respect excellent. We have, for example, grouped under each of the primary colors, all the tints of each respective color that the dyer can produce, and be- tween each large division the mixtures of color producing the neutral tones, and the inter- blending shades which may be required to copy the artist with fidehty. Skeins of worsted thus arranged are ever ready for the English mosaicisti in rug-work. Such is the material. Now to describe the manner of proceeding. In the first place an artist is employed to copy, of the exact size required for the rug, a work of Landseer's or any other master, which may be selected for the purpose. Although the process of copying is in this case mechanical, considerable skill is required to produce the desired result. This will be familiar to all who have observed the peculiar characteristics of the Berlin wool-work pat- tei'ns. The picture being completed, it is ruled over in squares, each of about twelve inches. These are again interruled with small squares, which correspond with the threads of which the finished work is to consist. This original being completed, it is copied upon lined paper by girls who are trained to the work, each girl having a square of about twelve inches to work on. These are the copies which go into the manufactory. A square is given to a young woman whose duty it is to match all the colors in wool. This is a task of great deli- cacy, requiring a very fine appreciation of color. It becomes necessary in many cases to com- bine two threads of wool, especially to produce the neutral tints. It is very interesting to ob- serve the care with which every variety of color is matched. The skeins of worsted are taken, and a knot or knob being formed, so as to increase the quantity of colored surface, it is brought down on the colored picture ; and, when the right shades have been selected, they are numbered, and a corresponding system of numbers are put on the pattern. In many of the rugs one hundred colors are employed. The selecter of colors works under the guidance of a master, who was in this case a German gentleman, and to his obliging and painstaking kindness we are much indebted. Without his very exact description of every stage of the process, it would not have been easy to render this rare mosaic-work intelligible to our readers. When all the colored wools have been selected, they are handed, with the patterns, to young women, who are termed the •" mistresses of a frame," each one having under her charge three little girls. The "frame" consists of three iron stands, the two extreme ones being about 200 inches apart, and the other exactly in the middle. These stands are made of stout cast iron, and may be said to consist of two bowed legs, with two cross-pieces of iron, one at the top of the legs, and the other about fifteen inelies below, the space between them being that which is to be occupied by the threads of wool which are to form the required square block of wool. These frames are united together by means of cast-iron tubes, running from end to end. The observer is struck with the degree of strength which has been given to these frames. It appears that, for the purpose of merely holding together a few threads of wool, a much slighter frame might have been employed ; and we certainly were surprised when we were informed that, at first, many frames were broken, and that they were compelled to have the stronger ones at present in use. The cau.se of this will Ijc obvious, when we have proceeded a little further with our description. At one end of these frames sits the "mis- tress," with a stand before her, on which the pattern allotted to her is placed, and a verti- cal frame, over which the long colored worsteds are arranged. By the side of this young woman sits a little girl, who receives each worsted from the mistress, and hands it to one of two children, who are on either side of the frame. Commencing at one corner of the pattern, a thread is selected of the required color, and handed to the fir.st girl, who passes it to the second, who.se duty it is to fasten it to a ■stiff, but slight liar of steel, about half an inch in width, which passes from the upper to the under ))ar of the frame. The third girl receives the thread, and carries it to the lower end of the frame, and fastens it to a simihir bar of steel at that end, The length of each thread of worsted is rather more than 'ioo inches. It is well known that twisted wool iloes not lie quite straight, without some force is applied to it ; and of course the finished pattein would be incomplete, if all the threads did not observe the truest parallelism to each other. 778 MOSAIC WOOL WORK To effect this, a stretching force equal to four pounds is required to every thread. The child who carries the thread, therefore, pulls the worsted with this degree of force, and fastens it over the steel bar. Every block, forming a foot-square of rug-work, consists of fifty thousand threads : therefore, since every thread pulls upon the frame with a force equal to four pounds, there is a direct strain to the extent of 250,000 pounds upon the frame. When this is known, our surprise is no longer excited at the strength of the iron- work ; indeed, the bars of hardened steel, set edgeways, were evidently bent by the force exerted. Thread after thread, in this way, the work proceeds, every tenth thread being marked by having a piece of white thread tied to it. By this means, if the foreman, when he ex- amines the work, finds that an error has been committed, he is enabled to have it corrected, by removing only a few of the threads, instead of a great number, which would have been the case, if the system of marking had not been adopted. This work, requiring much care, does not proceed with much rapidity, and the constant repetition of all the same motions through a long period would become exceedingly monot- onous, especially as talking cannot be allowed, because the attention would be withdrawn from the task in hand. Singing has therefore been encouraged, and it is exceedingly pleas- ing to see so many young, happy, and healthy faces performing a clean and easy task, in unison with some song, in which they all take a part. Harmonious arrangements of color are produced, under the cheerful influence of harmonious sounds. Yorkshire has long been celebrated for its choristers, and some of the voices which we heard in the room devoted to the construction of the wool-mosaics bore evidence of this natural gift, and of a consider- able degree of cultivation. The " block," as it is called, is eventually completed. This, as we have already stated, is about a foot square, and it is 200 inches long. Being bound, so as to prevent the disturbance of any of the threads, the block is cut by means of a very sharp knife into ten parts, so that each division will have a depth of about 20 inches. Hearth-rugs are ordinarily about eight feet long, by about two feet w ide, often, however, varying from these dimensions. Supposing, however, this to represent the usual size, twelve blocks, from as many different frames, are placed in a box, with the threads in a vertical position, so that, looking down upon the ends, we see the pattern. These threads are merely sustained in their vertical order by their juxtaposition. Each box therefore, will contain 800,000 threads. The rug is now, so far as the construction of the pattern is required completed ; and the cost of producing the " block," of 200 inches in depth, eight feet in length, and two feet wide, in- cluding the cost of wool, and the payment for labor, is little short of £800. When, how- ever, it is known that these threads are subsequently cut into the length required to form the rug, and that these lengths are but the three-sixteenths of an inch in depth, it will be evident that the number of those beautiful carpets which can thus be obtained, renders the manufacture fairly remunerative. The boxes into which the rugs are placed are fixed on wheels, and they have movable bottoms, the object of which will be presently understood. From the upper part of the immense building devoted to carpet manufacture, in which this mosaic rug-work is carried on, we descend with our rug to the basement store. Here we find, in the first place, steam chests, in which India-rubber is dissolved in eamphene. It may not be out of place to observe that eamphene is actually spirits of turpentine, carefully rectified, and deprived of much of its smell by being distilled from either potash or soda. Recently prepared eamphene has but little of the terebinthinous odor, but if it is kept long, and especially if it is exposed to the air, it again acquires, with the absorption of oxygen, . its original smell. This is of course avoided in the manufacture of such an article as a hearth-rug as much as possible. The eamphene is used as fresh as possible, and in it the India-rubber is dissolved, until we have a fluid about the consistence of, and in appearance like, carpenter's glue. In an adjoining room were numerous boxes, each one containing the rug-work in some of the stages of manufacture. It must now be remembered that each box represents a completed rug — the upper ends of the threads being shaved off", to present as smooth a sur- face as possible. In every stage of the process now all damp must be avoided, as wool, like all other porous bodies, has a tendency to absorb and retain moisture from the atmosphere. The boxes, therefore, are placed in heated chambers, and they remain there until all moist- ure is dispelled ; when this is effected, a layer of India-rubber solution is laid over the surface, care being taken, in the application, that every thread receives the proper quantity of tlie caoutchouc ; tliis is dried in the warm chamber, and a second and a third coat is given to the fibres. While the last coat is being kept in the Avarm chamber, free from all dust, sufficiently long to dissipate some of the eamphene, the surface on which the rug is to be placed receives similar treatment. In some cases ordinary carpet canvas only is employed ; in others, a rug made by weaving in the ordinary manner is employed, so that either side of the rug can be turned up in the room in which it is placed. However this may be, both surfaces are properly covered with soft caoutchouc, and the "backing" is carefully placed on the ends of worsted forming the rug in the box. By a scraping motion, the object of MUREXIDE. 779 which is to remove all air-bubbles, the union is perfectly effected ; it is then placed aside for some little time, to secure by rest that absolute union of parts, between the two india- rubber surfaces, which is necessary. The separation of the two parts is after this attended with the utmost ditficulty ; the worsted may be broken by a forcible pull, but it cannot be removed from the india-rubber. The next operation is tliat of cutting off the rug; for this purpose a very admirable, but a somewhat formidable machine is required. It is, in principle, a circular knife, of twelve feet diameter, mounted horizontally, which is driven, by steam- power, at the rate of 170 revolutions in a minute. The rug in its box is brought to the required distance above the edge of the box, by screwing up the bottom. The box is then placed on a rail, and connected with a tolerably fine endless screw. The machine being put in motion, the box is carried by the screw under the knife, and by the rapid circular motion, the knife having a razor-like edge, a very clean cut is effected. As soon as the rug is cut off, to the extent of a few inches, it is fastened by hooks to strings which wind over cylinders, and thus raise the rug as regularly as it is cut. This goes on until the entire rug is cut off to the thickness of three sixteenths of an inch. The other portion in the box is now ready to receive another coating, and the application of another surface, to form a second rug, and so on, until about one thousand rugs are cut from the block prepared as we have described. The establishment of the Messrs. Crossley, which gives employment to four thousand people, is one of those vast manufactories of w hich England may proudly boast, as examples of the industry and skill of her sons. Here we have steam engines urging, by their gigan- tic throes, thousands of spindles, and hundreds of shuttles, and yet, notwithstanding the human labor which has been saved, there is room for the exertion of four thousand people. The manner in which this great mass of men, women, and children is treated, is marked in all the arrangements for their comfort, not merely in the great workshop itself, but in every division of that hill-encompassed town, Halifax. Church, schools, and park proclaim the high and liberal character of those great carpet manufacturers, one division, and that a small one, of whose works we have described. MOULDS, ELASTIC. Being much engaged in taking casts from anatomical prepara- tions, Mr. Douglas Fox, surgeon, Derby, found great difficulty, principally with hard bodies, which, when imdercut, or having considerable overlaps, did not admit of the removal of moulds of the ordinary kind, except with injury. The difficulties suggested to him the use of elastic moulds, which, giving way as they were withdrawn from complicated parts, would return to their proper shape ; and he ultimately succeeded in making such moidds of glue, which not only relieved him from all his difficulties, but were attended with great advantages, in consequence of the small number of pieces into which it was necessary to divide the mould. The body to be moulded, previously oiled, must be secured one inch above the surface of a board, and then surrounded by a wall of clay, about an inch distant from its sides. The clay must also extend rather higher than the contained body : into this, warm melted glue, as thick as possible so that it will run, is to be poured, so as to completely cover the body to be moulded : the glue is to remain till cold, when it will have set into an elastic mass, just such as is required. Having removed the clay, the glue is to be cut into as many pieces as may be necessary for its removal, either by a sharp-pointed knife, or by having* placed threads in tlie requi- site situations of the body to be moulded, which may be drawn away when the glue is set, so as to cut it out in any direction. The portions of the glue mould having been removed from the original, are to be placed together and bound round by tape. In some instances it is well to run small wooden pegs through the portions of glue, so as to keep them exactly in their proper positions. If the mould be of considerable size, it is better to let it be bound with moderate tightness upon a board to prevent its bending whilst in use ; having done as above described, the plaster of Paris, as in common casting, is to be poured into the mould, and left to set. In many instances wax may also be cast in glue, if it is not poured in whilst too hot, aa the wax cools so rapidly when applied to the cold glue that the sharpness of the impression is not injured. Glue has been described as succeeding well where the elastic mould is alone applicable ; but many modifications are admissible. When the moulds are not used soon after being made, treacle should be previously mixed with thq glue (as employed by printei-s) to pre- vent its becoming hard. The description thus given is with reference to moulding those bodies which cannot be so done by any other than an elastic mould ; but glue moulds will be found greatly to facili- tate casting in many departments, as a mould may be frequently taken by this method in two or three pieces, which would, on any other i)rinciple, require manv. MUREXIDE. Syn. Purpnrate of Ammonia. C'lrN'O'^ Murc'xide is one of those substances which, although investigated by many chemists of great reputation, has long been regarded as of uncertain constitution. This is the more remarkable from the fact that, 780 MUREXIDE. owing to its extreme beauty, it has always attracted a large amount of attention. It is in- variably formed when the product of the action of moderately strong nitric acid on uric acid is treated with ammonia. The process, however, is rather valuable as a test of the presence of uric acid, than as a method of procuring murexide. Dr. Gregory, who has given much attention to the best methods of preparing the substance in question, has jiublished the following formula for working on the small scale: — "Four grains of allox- antine and seven grains of hydrated alloxan are dissolved together in half an ounce by measure of water by boiling, and the hot solution is added to one-sixth of an ounce by measure of a saturated or nearly saturated solution of carbonate of ammonia, the latter being cold. This mixture has exactly the proper temperature for the formation of murex- ide ; and it does not, owing to its small bulk, remain too long hot. It instantly becomes intensely purple, while carbonic acid is expelled ; and as soon as it begins to cool, the beautiful green and metallic-looking crystals of murexide Vjegin to appear. As soon as the liquid is cold, these may be collected, washed with a little cold water, and dried on filter- ing paper. The analyses of murexide are rather discordant, the carbon in all of them being in excess. This arises from the very large amount of nitrogen present, a certain portion becoming acidified passes into the potash apparatus, causing an undue increase in its weight. There appears no doubt whatever that the formula C'^X^lPO'^ represents its true com- position, ilurexide is formed when uramile, murexane, or dialuramide, as it is sometimes called, is boiled with peroxide of mercury. Dr. Gregory regarded murexane as a separate substance, and as identical with pur])uric acid : he also considered C'X^H^O^ as its probable formida. This appears from more recent researches to be incorrect, as murexane is doubt- less the same substance as uramile, while purpuric acid, which is bibasic, is represented by the formula C'lPN'O". Tlie formulaj above given for murexide and uramile renders the reaction of peroxide of mercury with the latter easily intelligible ; it is, in fact, a very simple case of oxidation, thus : — 2C»X'H'0''-|- 20r=C"'X'IF0'- -f 2H0 Uramile. Murexide. The limits of this work preclude any further notice of the scientific relations of mui-ex- ide, but it is necessary that we should consider it in its character as a dye-stuff". It has been found that murexide forms a series of beautiful compounds with certain metallic oxides, more especially lead and mercury, and these compounds have been employed to a very large extent in the dyeing, and more especially printing of cotton goods. It is plain that if uric acid were only obtainable from the urine of serpents or the sediments from the urine of mammalia, it could never be made use of in the arts. It happens, however, that the solid urine of birds contains it in large quantity, and since we have become acquainted with the vast deposits of guano existing in various parts of the globe, tlie manufacture of murexide has been carried out on a scale which would, a few years ago, have appeared im- possible. We must, in order to be -c-lear, divide the process into two parts, one being the preparation of uric acid from guano, the other the conversion of the acid into murexide. Preparation of uric acid from guano. — ^^In order to get Tid, as much as possible, of the impurities contained in the guano, it is in the first place to be treated with muriatic acid, which will remove carbonate and oxalate of ammonia, carbonate and phosphate of lime, and ammonio-magncsian phosphate. The uric acid will also be liberated from the substances with which it may l)c in combination. The operation may be performed in a leaden vessel, heated with a leaden coil, through which steam passes. It is essential to success that the guano be added slowly, otherwise the violent effervescence, which is caused by the decom- position of the carbonates by the acid, would cause the liquid to escape from the vessel. The mixture of guano and mnriatic acid is then to be heated for an hour, after which it may be run off" into tubs, to bo washed with water by decantation. The first washings con- tain a large quantity of ammonia in the state of sal ammonia ; it should be worked up in some way, in order to prevent the loss of so vahialjje a salt. As soon as the residue of the guano is sufficiently washed, it may be transferred to cloth filters and allowed to drain. The residue from the action of muriatic acid upon 200 lbs. of guano can now be treated by Draun's process for the extraction of the uric acid. It is to be placed in a copper boiler of sufficient capacity, and boiled for an hour with 8 pounds of caustic .soda and 120 gallons of water. It must be constantly stirred. Two or three pounds of quicklime are now to be slaked, enough water is then to be added to make the whole into a thin paste, which is to be poured into the mixture of caustic soda and guano residue. After a quarter of an hour's boiling, the fire is to be removed and the whole allowed to repose until clear. The bright liriHiant green fluid. Tlie fluid lielow is then to be removed by means of a pipette, furnished at tlie U])per end with a hollow elastic ball of vuleajiized caoutchouc. By this means suction with the lips becomes unnecessary, and the vapors of hyponitric acid are prevented from irritating the lungs. The indifferent hydrocarbon — that is, the fluid unacted on by the acid — is as yet 788 NAPHTHA. by no means pure ; it obstinately retains traces of the benzole and C"H» series. It is, there- fore, to be transferred to a flask furnished with a well fitting stopper, and treated -with nitric acid (spec. grav. To) a considerable number of times. This second treatment may, without danger of any explosive reaction, be made upon one or two ounces of the partially purified hydrocarbon. When it is found that the sejjurated nitric acid no longer produces milkiness on being thrown into water, it may be assumed that the benzole and C"!!" class of hydro- carbons are entirely removed. When the treatment with acid has been repeated a suffi- cient number of times, the fluid is to be placecl in a clean flask and well agitated with a solution of caustic potash, which will remove the nitrous vapors which are the cause of the green color. The j>urified hydrocai-bon is then to be separated by a tap funnel from the water, and dried by digestion with sticks of caustic potash. If it be desired to obtain the radi- cal in a state of absolute purity, it must be distilled three or four times over metallic sodium. The indifferent hydrocarbons obtained by the above process are colorless mobile fluids, having an odor somewhat resembling the flowers of the white thorn. They are very vola- tile, even at low temperatures, and have an average density of about 0-716. When the fractions with proper boiling points have l)een selected, it will be found that tiiey corre- spond in specific gravity, percentage composition, and vapor density with the radicals of the alcohols, as will appear by the following table, where the experimental results obtained by the author of this article in his examination of Boghead naphtha are compared with the numbers found by other observers with the radicals obtained by treatment of the hj-driodic ethers by sodium, and also by the electrolysis of the fatty acids. Comparative Table of the Physical Properties of the Alcohol Radicals, as ohtaincd from Boghead Naphtha, with those procured from other sources. Formul.-B. Boiling Points, Fahr. Radicals. Frankland. Kolbe. Wurtz. Brazier and Gosslett. C. G.Williams. Propvle . . - Buty'le Ainyle C.iproyle 0121114 C"H18 C20H22 C24H26 311° 226-4° 2'22-8' 316-4 395-6 154-4° 2462 SlS-2 395-6° 895-6 ! 1 Densities. Vapor Densities. Radicals. Formula-. Frankland. Kolbe, Wurtz, at 64-4'. at 3-2'. C. G.Williams, at 64-4'. Frankland.', : at 51-8.° ;Ko'be Wuriz C. G. Wil- liams. Theory. Propvle Buty'le Amyle Capfoyle Ci2Hi« C16H18 C-Jl)II22 C24H26 4-S99 0-6940 0-7057 - 0-7413 - 0-7574 0-6745 0-6945 0-7365 0-7563 0-7704 1 - - 4 053 4-070 4-956 5-9S3 2-96 3-SS 4 93 5-S3 2-97 3 94 491 5-S7 It has been said that the above hydrocarbons distilled away from the bromine compound in company with othere which were removed by treatment with nitric acid. It was sub- sequently found that the products formed by the action of the acid were nitro-compounds belonging to the benzole series. The bromine compound contains the C"H° series of hydro- carbons, the individual member being determined by the boiling point of the fraction selected for experiment. If we select that portion boiling steadily between 1G0° and 170°, we shall have a bromine compound of the formula C''*H'^Br° ; but if the boding point of the naphtha lies between 180° and 190°, the bromine compound will be C^H^lir^. It is ex- ceedingly remarkable that if either of these substances be treated alternately with alcoholic potash and sodium, the original hydrocarbon is regenerated. By the mode of operating indicated above it is possible, therefore, to obtain two out of the three series of hydrocarbons in a pure state. The third, namely the benzole series, must be recognized bj obtaining products of decomposition. The acids and bases accompanying the hydrocarbons in Boghead naphtha have not yet been fully investigated ; it has, however, been ascertained that certain members of the phenole series of acids and pyridine cla.s3 of bases are always present. The quantities present in the naphtha of commerce are small in consequence of the purification of the fluid by the agency of oil of vitriol, followed by a treatment with caustic soda. — C. G. W. NAPHTHA, Bonk. Syn. Bone Oil ; Dippel's Animal Oil. This fluid is procured in large quantities during the operation of distilling bones for the preparation of animal char- coal. The hydrocarbons of bone oil have not as yet been examined, but it has been found that the benzole series are present, accompanied by large quantities of basic oils. The acid portions are also uninvestigated. The bases have been very fully studied by Dr. Anderson, who discovered in bone oil the presence of no less than ten bases, several of them being quite new. The odor of bone oil is exceedingly offensive and difficult of removal. It does not arise entirely from the presence of the powerfully Bmelling bases, for even after repeated treat- NAPHTHA, 789 ment with concentrated acids it retains its repulsiveness. This is partly owing to the pres- ence of some unknown neutral nitrogenous bodies. When a slip of deal wood is moistened with hydrochloric acid and held over a vessel of crude bone oil, it rapidly acquires a deep crimson tint. This is in consequence of the presence of the extraordinary basic substance pyrrol. The latter, when in a crude state, possesses a most disgusting smell, so much so, that the offensiveness of bone oil was at one time mainly attributed to its presence. It has, however, been recently discovers', that pyrrol when perfectly pure has a most fragrant and delightful perfume, somewhat recalling that of chloroform, but still more pleasing. The basic portion of bone oil may be extracted by shaking it up with moderately strong oil of vitriol. This must be done with precaution, as large quantities of gases are evolved, consisting of carbonic acid, hydrosulphuric and hydrocyanic acids. The liuid when permit- ted to repose separates into two layers, the upper being the purified oil, and the lower the acid solution of the bases. The latter being separated is to be distilled until about one-third has passed over. This distillate will contain the chief portion of the pyrrol. The head of the still is then to be removed and the fluid boiled for some time, to remove the last trace. The acid solution, after filtration through charcoal, is to be supersaturated with lime and distilled. The distillate contains the whole of the bases. The apparatus should be so arranged that those bases which are excessively volatile, and consequently come over as gases, may be received in hydrochloric acid. The hydrochloric solution and the oily bases are to be examined separately. The former is to be evaporated carefully to the crystallizing point and then allowed to cool. By this means the ammonia may be removed by crystalU- zation as chloride of ammonium. When no more sal-ammoniac can be obtained by crystallization, the mother liquid is to be treated with potash, in an apparatus so arranged that any gaseous products evolved may be collected in hydrochloric acid. The retort must have a thermometer in the tubulature to enable the temperature to be properly regulated. All the bases distilling below 212° are to be received in hydrochloric acid, and their presence demonstrated by converting them into platinum salts, and fractionally crystallizing. The bases distilling above 212"" are to be separated by fractional distillation. An examination of the hydrochloric solution will, according to Dr. Anderson, demonstrate the presence of methylamine, propylamine, butyl- aniine, and amylamine. The following table contains the names and physical properties of the bases which are contained in that portion of the basic oil which distils above 212'. The amylamine, and even the propylamine, can be separated from the basic oils by frac- tional distillation, instead of the fractional crj'stallization of platinum salts, but the latter involves less labor. Table of the Physical Properties of the Pyridine Series of Bases. Base. Formula. Boiling Point Density at 32°. Yapor Density. Experiment. Calculation. Pyridine - - C'H^X Picoline - - ' C"H"N Lutidine - - ! C"H'N Collidine - - i C'=H"N 242° 275° 310° 356° 0-9858 0-9613 0-9467 0-9439 2-916 3-290 3-839 2-734 3-214 3-699 4-137 Bone oil will not become very valuable as a naphtha for general purposes until some cheap method of removing its odor has been discovered. The Oleum animale dipcllii of the older chemists and pharmaceutists was prepared by distilling bones ; it was very similar in properties to bone oil. — C. G. W. NAPHTHA FROM C.\ouTCiiouc. Syn. Caoutchoucine ; Caoutchine. Caoutchouc, by destructive distillation, yields several hydrocarbons, the accounts of which are contradictory. By repeated rectifications they may be separated into fluids of .steady boiling points. The late Dr. (ircgory succeeded in obtaining a fluid hydrocarbon from caoutchouc which distill- ed at 96', but when treated with sulphuric acid, and the fluid separated by means of water, another hydrocarbon was obtained boiling at 428". It is most probable, however, that the true composition of caoutchoucine has not yet been made out. This will appear by con- sulting the analyses yet made, many of them indicating too low a hydrogen for the C"II" series, and more nearly approximating to n (C'lP). The author of this article is engaged .in a new examination of these hydrocarbons. It is quite plain, however, that caoutchine is, in every sense of the term, a naphtha. Caoutchine is one of the best solvents known for india-rubber. — C. (r. W. X APHTHA, Coal. Ordinary coal naphtha is procured by the distillation of coal tar. The latter is placed in large iron stills, holding from 800 to 1,500 gallons, and distilled by direct steam. As soon as specific gravity of the distillate rises to 0-010, the naphtha is pumped into another still, and distilled with direct steam until the distillate again becomes of the density O-'.Hn. It then constitutes what is termed "rough naphtha." 790 iJ APHTHA. The residue obtained in the first distillation is run off into cisterns or tar ponds to allow of the removal of the water. This residue is called boiled tar. Pitch oil may be obtained from it by distillation with the naked lire, every 1,000 gallons will yield about 320 gallons of pitch oil. The residue of pitch in the still is run out while in a melted state. The rough coal naphtha contains a great number of impurities of various kinds, the principal cause of the foul odor being the organic bases described in the article Naphtha, Boxe. To remove these the naphtha is transferred to large cylindrical vessels lined with lead. These vessels contain a vertical axis passing down them, supporting blades of wood covered with lead, and pieiced with holes. The axis or shaft has, at its upper end, a crank to enable it to be rotated. The naphtha having been run into the vessel, sulphuric acid is added, and the shaft with its blades made to revolve. By this means the naphtha and acid are brought into intimate contact. The whole is then allowed to settle, and the vitriol which has absorbed most of the impurities, and acquired, in consequence, a thick tarry consistence, is run off". Tills acid treacly matter is known in the works as " sludge." The naphtha floating above the sludge is then treated a second time with acid, if the naphtha be required of good quality. During the process, the naphtha acquires a sharp smell of sulphurous acid, and retains a certain amount of sulphuric acid in solution. The next process is to treat it with solution of caustic soda to remove these impurities. This may be effected in an apparatus similar to the first. The naphtha, after removal of the caustic liquor, is next run off into a still, and rectified; it then fbims the coal naphtha of commerce. The ordinary naphtha of commerce is often very impure, owing to insufficient treatment with oil of vitriol. The author of this article has obtained from one gallon of commercial naphtha as much as one and a half ounces of the intensely odorous picolinc, mixed with certain quantities of other bases of the same series, and also traces of aniline. In describing coal naphtha, we shall not confine ourselves to the description of those substances which come over in distillation between any given temperature, but shall take a cursory review of the nature and properties of most of the substances produced by the distillation of coal tar. It will be unnecessary here to enter into a minute description of the acids existing in coal tar, inasmuch as they have already been treated of in the article Carbolic Acid. On the basic constituents of coal naphtha. — Coal tar is particularly rich in bases. They are found accompanying all the fluid naphthas and oils, and probably cannot be separated, by distillation alone, from any of the hydrocarbons of coal naphtha except benzole. It is highly remarkable that while coal tar yields all the pyridine series of bases found in bone oil, no traces of the alcohol series have yet been discovered. At the time that the author of this article commenced his experiments on the coal naphtha bases, there were only three known to be present, namely, aniline, ehinoline, and pieoline. The two former were dis- covered in coal tar by Runge, who called them kyanol and leukol. Pieoline was discovered by Dr. Anderson, of Glasgow. The discovery was, at the time, of great value, it being the first instance on record of isomerism among volatile bases. The number of isomeric bases now known is very great, and fresh instances are becoming known every day. The follow- ing are the bases known to be present in coal tar, with their formulae. They will be found mentioned under their names in this work. The physical properties of the pyridine series are given under Naphtha, Boxe. Pyridine Pieoline Lutidine Collidine - C'"!! =N - C'-II "N - cm "N -C""TI"N Pvrrol - Chinoline Lepidine Cryptidine Aniline - CnPN. - C"H 'N - C^°H ^V C"H"N -C'^'N On the hydrocarbons of coal naphtha — The following are the principal constituents of those coal naphthas the boiling points of which range between 190 ' and 350° : Base. Formula. Boitln? Point. Specific Gravity. Benzole - Tolnolc - Xylole - Cumolo - Cymole - - - C'-IP C20jgi4 177° 230° 259° 304° 347° 0-850 at 60° 0-870 0-861 " 57° The fluid hydrocarbons boiling above this point have not been well studied. Ordinary coal naphtha, in addition to the above hydrocarbons, contains traces of the homologues of olefiant gas, alluded to in the article Naphtha, Boghead. All the above-mentioned hydrocarbons may be separated from each other by careful and sufficiently numerous fractional distillations. It is proper before considering them as pure, to shake them up several times with oil of vitriol, and, after well washing first with water, NAPHTHA. 791 and afterwards with an alkaline solution, to dry them very carefully with chloride of calcium or sticks of potash. It will be observed that in the above table the specific gravities of the hydrocarbons are not in harmony ; this arises from the iluids upon which the experiments were made not having all been procured from the same source ; for it has been found that the same bodies, as procured from different sources, often present small but appreciable differences in odor, density, boiling point, and other physical properties. The benzole of coal naphtha may almost entirely be separated by distilling in an appara- tus first devised for the purpose by Mr. C. B. Mansfield. The annexed figures from my "Handbook of Chemical Manipulation," illustrate the vessels I am in the habit of employ- ing for the purpose. Fig. 464 consists of a copper or tinned iron still, a, holding about two gallons. The flange, b 6, is merely to support the apparatus in the ring of a gas or charcoal furnace, preferably the former. A wide worm, c <■, passes through the top of the still into a water-tight cistern, d d. The worm ends in a discharge pip.e, e. The latter is to be at- tached to a common worm-tub containing cold water. The crude benzole, or coal naphtha, is to be placed by means of the opening/ into the still, and all the joints of the apparatus being closed, and effectual condensation insured, the fire is to be lit. The naphtha soon begins to boil, but nothing comes over, because the water 'va.d d effects condensation. In a short time, however, the water in dd begins to get warmer, and, as soon as IVJ" is reached, benzole begins to come over, and is perfectly condensed in a second worm, kept cold by means of water. It is plain that as the fluids of higher boiling points begin to come over, the water '\xi d d will boil, but distillation then ceases entirely. The reason of this is, that nothing can make the head c c hotter thau 212^, because of its being surrounded with water. All hydrocarbons that are not volatile at 212° are consequently condensed there, and fall back into a. The benzole distilling over is quite pure enough for all ordinary purposes. It may, if required very pure, be rectified a second time in the same apparatus, taking care that the head does not get hotter than 180° or 190''. If the benzole is wanted absolutely free from its accompanying hydrocarbons, it must be purified by freezing. For this purpose the rectified benzole is to be placed in a thin glass or metal vessel, and sur- rounded with snow or pounded ice mixed with salt. The whole apparatus is to be surround- ed with sawdust and covered with woollen cloths to prevent access of heat. As soon as the benzole is frozen, it is to be placed in a funnel and allowed to drain. The solid mass when thawed is pure benzole. By this mode of proceeding, a considerable quantity of fluid is always accumulated which refuses to freeze and yet boils at the proper temperature for benzole. I have found it to contain a small quantity of the C"!!" series of hydrocarbons (homologous with olefiant gas). Mr. Church states it to contain benzole in a peculiar con- dition ; he calls it parabenzole. The presence of the C"!!" series may always be proved by the readiness with which the fluid decolorizes bromine water. 464 465 A simpler form of apparatus for rectifying benzole, and one that answers almost as well, is that represented in fig. 465. It will be seen that the worm c c of fig. 464 is replaced by a straight tube. The mode of use is precisely the same. Where the benzole is to be extracted from coal naphtha on the large scale, the follow- ing apparatus will be found convenient: — The boiler a «, {-fig. 400) surrounded bv a .steam jacket, is connected at its upper extremity with a head, h\ answering to the worm c in AV/. 404. The head plays into the worm tub (/ ; the benzole being conveyed by the exit pipe e to the reservoir or close tank in whicii it is to be stored. The tub c c c c contains water to condense the hydrocarbons which arc to be removed from the benzole. In order to save time it is convenient at the commencement of the operation to heat the water m c cc c to about 170° ; this is effected by means of the steam pipe I I /, which is connected with the boiler/. Tlie steam is admitted to the jacket of the still by means of the pipe g. Tlie steam can bo regulated or stopped altogether by means of the stop-cock n. The cock m is to regulate the admission of steam to the vessel c c c c. The man-hole is represented at k. Y92 NAPHTHA. A small cock to allow the condensed water in the jacket to be run off, is seen at i. Unless the naphtha is of the best quality the benzole will be dithcult to extract by the heat of the jacket alone. It will then be necessary to send direct stcain into a a. When no more 466 benzole comes over, the remaining naphtha is to be run out of the still by the stop-cock n. Although the l)oilcr/' is, for the sake of space, represented in the figure as if placed beneath the support of the condenser or worm tub, it should in practice be removed to a consider- able distance for fear of the vapor of the hydrocarbon reaching the stoke-hole and causing an explosion. The condenser b may be arranged in the form of a worm like c mficj. 464, but the precaution is scarcely necessary if the chamber at 6, {f(j. 466) be made sufficiently capacious. The benzole obtained in the above apparatus is, of course, contaminated with toluole ; if, however, the rectification be repeated, the water in the chamber c c c c not being permitted to become hotter than 180° F., the resulting benzole will be almost pure. One distillation is amply sufficient for the preparation of the commercial article. A rectifying column somewhat like Coffey's still may also be employed for preparing benzole. The less volatile naphtha remaining in the still is by no means valueless ; it is adapted for almost all the purposes for which ordinar}' coal naphtha is applicable. By removing the fluid by the tap A, and distilling it in an ordinary still, a very good coal naphtha of a density of about 0'S70 will be obtained. The number of processes and patents which have been published relating to coal naph- tha is immense. There is, as a general rule, an extreme sameness in them. Each inventor uses the processes of his predecessors with some slight alteration or modification, and patents them as if involving an important discovery. It is true that, in some few instances, these alterations are very valuable, but the general feeling with which one rises from the perusal of patents connected with coal naphtha is, that there is nothing really new in them. All processes for their purifications consist, essentially, of treatments with strong oil of vitriol followed by alkalies. It is remarkable to observe the difference in the ideas of inventors and operators with regard to the part played by sulphuric acid in the purification of naph- NAPHTHA. 793 thas. It is by no means uncommon to hear the workmen, and even those who have the direction of naphtha works, attribute the dark color which naphthas acquire by contact with oil of vitriol, to the latter '* precipitating out the tar." The fact i^^, that a carefully dis- tilled naphtha does not contain any tar. The dark color is chiefly due to the removal of the hydrocarbons homologous with olefiant gas. All bodies belonging to this series dissolve with a red color in sulphuric acid, and the fluid on keeping soon begins to evolve sulphurous acid and turn dark, sometimes nearly black. If the naphtha has been insufficieut- ly rectified, it will contain naphthaline, and this will readily unite with the sulphuric acid to form a conjugate acid of dark color. It is extremely curious that naphthas which contain large quantities of naphthaline will often distil without the latter crystallizing out. It is volatilized in the vapor of the naphtha, and therefore escapes observation. But if a little chlorine be poured into the fluid, or if a little chloride of lime be added, followed by an acid, and the fluid be then distilled, the naph- thaline will come over in the solid state, so that it can be removed by mechanical methods. It does not appear to be due to the formation of Laurent's chloride of naphthaline, for the product onl}' contains traces of chlorine. Benzole has been much used of late to remove greasy and fatty matters from cotton, wool, silk, and mixed fabrics. It is by no means essential that the benzole should be absolutely pure for this purpose. By this it is meant that the presence of naphthas boiling somewhat above 177' does not materially aftect the usefulness of the fluid. If, however, the naphtha is to be employed for removing greasy stains from dresses, gloves, or other articles to be worn, the purer and more volatile the hydrocarbon, the more readily and completely the odor will be removed by evaporation. Mr. F. C. Calvert has patented the application of benzole to some purposes of this kind. He first purifies the naphtha by means of sulphuric acid and caustic alkalies in the usual manner, and then rectifies it at a temperature not exceeding 212'. For this purpose the apparatus described in firt. 466 will be found well suited. The in- ventor applies the rectified coal naphtha, or nearly pure benzole, to the following purposes : — 1st, for removing spots and stains of grease, i. c. fatty or oily matters, tar, paint, wax, or resin, from cotton, woollen, silk, and other fabrics, when, in consequence of its volatility, no mark or permanent odor remains ; 2d, for removing fatty or oily matters from hair, furs, feathers, and wools, and for cleaning gloves and other articles made of leather, hair, fur, and wool; 3d, for removing the fatty matters which exist naturally in wool; 4th, for removing, from wool, tar, paint, oil, grease, and similar substances used by farmers for marking, salving, and smearing their sheep ; 5th, for cleansing or removing the oily or fatty matters which are contained in cotton waste that has been used for cleansing or wiping machinery, or other articles to which oil or grease has been applied. In order to remove the above matters by means of coal naphtha, the articles, if small, are merely rubbed with it. On the large scale the matters to be operated on are placed in suitable vessels, and the naph- tha is run in. After contact for some hours the fluid is run off, and the fabrics are passed through squeezers and submitted to strong pressure to remove the greater portion of the benzole or naphtha. The naphth;is which run out are distilled off, so that the greasy matters may be preserved and used for lubricating machinery or other purposes. Furniture paste may also be made from light coal naphtha or benzole by the following process: — One part of wax and one of resin is to be dissolved in two parts of the liydrocar- bon, with the aid of heat. When entirely dissolved the whole is allowed to cool, and is then fit for use. It is a vexatious circumstance that no important practical use has been found for naph- thaline. It is true that it is used for the preparation of lampblack, but the (piantity employed for that purpose is but small. The quantity annually produced by the various gas-works is enormous. Its odor and volatility prevent its Ijeing applied to lubricating purposes. It often happens that much valuable time is lost by unscientific operators in endeavoring to remove the smell from such substances as naphthaline : they forget that the odor of a body of this class is a part of itself, and cannot be removed without its destruction. It is possible that the compounds of naphthaline may one day be applied to useful purposes. By treating naphthaline with excess of chlorine, and removing fluid substances with ether, a crystalline paste is obtained. This paste, dissolved in boiling benzole and allowed to repose, deposits beautiful rhombohedral crystals, often of large size. They have exactly the form of Iceland spar, and, like that substance, possess the power of double refraction. When nitronaphtha- line is treated with acetic acid and iron filings in the same manner as that employed by JI. Bechamp for the production of aniline, a base is obtained of the formula C-"'H''X ; it is called naphthalamine. It is, therefore, isomeric with cryptidine, but has no other point of resem- blance. The relation which appears to exist between naphthaline and alizarine is also very interesting, and suggestive of the idea that the former substance will not always be regarded as useless. It is said that naphthaline has been employed with advantage in the treatment of 794 NAPHTHA. psoriasis. M. Emery states that it succeeded in twelve out of fourteen cases. In the two where it failed, the one patient was a woman thirty years of age, who had been afflicted for eight years with psoriasis gyrata ; the other patient was a young man who had suflered for several years with lepra vulgaris. In the latter case, two months' treatment having effect- ed no good, pitch ointment v,-as substituted, which effected a cure in two months. The naph- thaline was employed in the form of ointment in the strength of 3 ss. to 3 i. of lard. The application is sometimes, however, attended with severe inflammatiou of the skin, which must be relieved with poultices. {L'' Experience, Oct. 6, 1842.) The dead oils, as the less volatile parts of coal tar are called, contain several substances, the nature of which is very imperfectly known. Among them maybe mentioned pyrene and chrysfene. The former has only been examined by Laurent, who gives the formula C^"H" for it. They are found in the very last portions that pass in the distillation of coal tar. They are also said to be produced during the distillation of fatty or resinous substances. The portions which distil last are in the form of a reddish or yellowish paste, which rapidly darkens in color on exposure to light. Ether separates it into two portions, one soluble, containing the pyrene, the other insoluble containing the chrysene. The pyrene may be obtained by exposing the etherial solution to a very slow temperature, which will cause it to crystallize out. The composition of pyrene is, according to Laurent, Experiment. Cnlculation. Carbon ... - 93-18 - - - C'° 93-7 Hydrogen - . - - 611 - - - H" 6-3 99-29 100-0 The portion insoluble in ether consists of chrysene in a tolerably pure state. I have found that it crystallizes on cooling from a solution in Boghead naphtha, in magnificent yel- low plates, with a superb lustre resembling crystallized iodide of lead. The following are the results of its analysis. My combustion was made upon chrysfene crystallized as above. Laurent. C. G. "W. Calculation. Carbon - - 94-83 94-25 94-63 94-74 C" 72 Hydrogen - 5-44 5-30 5-37 5-26 H* 4 100-27 99-55 100-00 100-00 76 The formula given above merely expresses the ratio of the elements ; no compound of chrvsene has yet been formed which will enable it* atomic weight to be determined with certainty. Laurent's analyses were calculated with old atomic weight of carbon. The heavier coal oils, when exposed to the action of a powerful freezing mixture, often deposit a mass of crystals only partly soluble in alcohol. The soluble portion consists of naphthaline; the other portion, which dissolves with difficulty, is a curious substance, the nature of which is at present not very well known ; it has been called anthracene, or para- naphthaline. It appears, from the analyses which have as yet been made, to be isomeric •with naphthaline. It fuses at 356°, and boils at about 580^ The density of its vapor, deter- mined at 848°, was 6-741°, agreeing very well with the formula C'"!!'^ which requires 6-643. This formula is one and a half times naphthaline, thus : C""!!" + C'"!!* :rr C=''H". Metanaphthaline is a peculiar substance which appears to be closely related to the above products. It is formed during the manufacture of resin gas. It is a fatty substance fusing at 158°, and distilling atabout 617° ; it is at present but little known. A substance which seems to be metanaphthaline has recently been imported in considerable quantity as a lubricating material. It is tinged of a yellow color, probably from the presence of traces of chrysene. NAPHTHA, Native. In a great number of places in various parts of the world, a more or less fluid inflammable matter exudes. It is known as Persian naphtha. Petroleum, Rock oil, Rangoon tar, Burmese naphtha, &c. These naphthas have been examined by many chemists, but the experiments have been exceedingly defective, and even the analyses most incorrect, for in most cases where a loss of carbon or hydrogen has been experienced, it has been put down as oxygen. The oil procured from the above source, when rectified and well dried, contains no oxygen. The constitution of all of them is probably nearly the same, the odor and physical characters closely agreeing in specimens obtained from widely different sources. A thorough investigation of the most plentiful and well marked of all of these naphthas (namely that Irom Rangoon) has been undertaken by MM. Warren De la Kue and Hugo Miiller, who have been engaged upon it for some years. They find the fluid to consist of two principal series of hydrocarbons, namely the benzole class and another unacted upon by acids, and apparently consisting of the radicals of the alcohols. In addition to the fluid hydrocarbons, Burmese naphtha contains a considerable quantity of paraffine. Burmese naphtha or Rangoon tar is obtained by sinking wells about 60 feet deep in the soil ; the fluid gradually oozes in from the soil, and is removed as soon as the quantity accumu- lated is sufficient. The crude substance is soft, about the consistence of goose grease, with a greeni.sh brown color, and a peculiar but by no means disagreeable odor. It contains only 4 per cent, of fixed matter. In the distillations, MM. De la Rue and Miiller employed super- NAPHTHA. Y95 heated steam for the higher, and ordinary steam for the lower temperatures. At a temperature of 212\ eleven per cent, of fluid hydrocarbons distil over; they are entirely free from paraffine. Between 230" and 290° F., ten per cent, more fluid distils, containing, how- ever, a very small quantity of paralfine. Between the last-named temperature and 320' F. the distillate is very small in quantity, but from that to the fusing point of lead, 20 per cent, more id obtained. The latter, although containing an appreciable amount of paraffine, re- mains fluid at 32° F. At this epoch of the distillation, the products begin to solidify on cooling, and 31 per cent, of substance is obtained of sufficient consistency to be submitted to pressure. On raising the heat considerably, 21 per cent, of fluids and paraffine distil over. In the last stage of the operation, 3 per cent, of pitch-like matters are obtained. The residue in the still, consisting of coke containing a little earthy matter, amounts to 4 percent. We thus have as the products in this very carefully conducted and instructive distillation, Below 212° - 230° to 293° - 293" to 320° - 320° to fusing point of lead Free from paraffine A little paraffine Containing paraffine, but still fluid at 320° At about the fusing point of lead, Sufficiently solid to be submit- ted to pressure Beyond fusing point of lead - - Quantity of paraffine diminishes - Last distilled Pitchy matters - - - ■ Residue in still .... Coke containing a little earthy impurity . . . . 110 10-0 200 Sl-0 210 3 40 100-0 All the above distillates are lighter than water. Almost all the paraffine may be extracted from the distillates by exposing them to a freezing mixture. In this manner, uoless than between 10 and 11 per cent, of this valuable solid hydrocarbon maybe obtained from Burmese naphtha. We may before long expect a full account of the substances contained in Rangoon tar. — C. G. W. NAPHTHA, SiiALK. The true constitution of .shale naphtha, or, as it is sometimes called in commerce "shale oil," has not yet been satisfactorily ascertained. In fact, to do so would involve a very laborious research, or rather series of researches, for the various shales or schists differ much in the quantities and qualities of the naphtha yielded by them. The bituminous shale of Dorsetshire contains much nitrogen and sulphur, arising to a great extent from presence of a large quantity of semi-fossilized animal remains. The crude naph- tha, consequently, is intolerably fuetid. By repeated treatments with concentrated sulphu- ric acid and caustic soda it may, however, be rendered very sweet. It then contains pretty nearly the same constituents as Boghead naphtha, i. c. benzole and its homologues, various hydrocarbons of the olefiant gas series, and small quantities of the alcohol radicals or iso- meric hydrocarbons. There are also present, previous to purification, carbolic acid and numerous alkaloids ; but, strange to say, in the samples I examined there was no trace of aniline to be found. There is little doubt that shales of this kind might be most profitably worked by one or other of the recently patented processes for the preparation of photogen and lubricating oil. French shale oils have been examined by Laurent and Sainte Evre, but the results are not of any very great value, because care was not taken to separate the various series of hydrocarbons from each other. It is true that Laurent fractionally distilled his oil, and Sainte Evre in addition treated his hycrocarbons with sulphuric acid, anhydrous phosphoric acid, and fused potash. These operations would remove basic and acid bodies, and much, if not all, of the homologues of olefiant gas, but the residue would contain indefinite mixtures of the benzole and radical series. Laurent's analyses have been quoted by Gerhardt to show that the hydrocarbons approach in composition the formula n(C"ir''). They are as follows: — SO" to 05° C 120° to 1'21° 109° Theory 11(0=112) Carbon - - 86-0 85-7 - 8(i-2 85-6 - 85-7 Hydrogen - - 14-3 141 - 13G 14-5 - 14-3 100-0 The above analyses are calculated according to the old atomic weight of carbon. M. Sainte Evre, by determining the vapor densities of the fractions, arrived at the fol- lowing Ibrmula for the hydrocarbons examined by him : — Boiling points Cent. Formula. 275" to 280° C^-^H^* 255° to 2G0° C"H" 215° to 220° C^IP' 132° to 135° C"H" 796 NATUEE-PPJNTIN. These results are worth very little except as showing where an excellent field exists for invc.-^tigation. Lament, by treating with boiling concentrated nitric acid that part of shale oil which boiled between 80' and 1 50 ' Cent., obtained an acid which he called ampelic ; it is apparently metameric with salicylic acid. Tiie same, or more probably a homologous substance, is procured by treating in the same manner the oil boiling between 130^ and 160^. Picric, or, as it is sometimes called, carbazotic acid, is also formed at the same time. Ampelic acid is a substance about wliich chemists have felt much curiosity ever since its discovery. It is much to be desired that a new investigation should be made upon it. The following are a few of its properties: — It is white, inodorous, almost insoluble in cold water, and only slightly soluble even when boiling ; the solution reddens litmus. It is easily dissolved by alcohol or ether ; from solution in those menstrua it is deposited under the form of a crystalline powder. It fuses somewhere about 200" Cent., and distils without alteration. This last property is a valuable one, as it will enable its vapor density, and consequently its atomic weight, to be easily determined with precision. From its solution in sulphuric acid it is precipitated unaltered by water. Gerhardt gives the following as some of the reactions of this interesting body. The solution of its ammonia salt precipitates chloride of calcium white, the precipitate is soluble in hot v.ater, and crystallizes on cooling. It is not precipi- tated by solutions of the chlorides of barium, strontium, manganese, or mercury. Acetate of nickel gives a greenish precipitate, acetate of copper greenish blue. Acetate and nitrate of lead gives white precipitates. The above experiments were made by Laurent in 1S37, and, as it is very probalile that he never obtained a perfectly pure substance, it is almost certain that valuable and novel results would be obtained on carefully repeating the entire investigation. At the same time, as benzoic acid is CH^O^'and ampelic acid according to its discoverer is C"H"0^, it is more than likely to be a product of oxidation of one of the homologues of benzole. Intimately connected with the oils of shale are the fluids yielded by the distillation of the numerous bitumens and asphalts found in various parts of the world. Undoubtedly these deposits will one day become of important use in the arts. The bitumen of Trinidad yields on distillation an intensely foetid oil, and also a very large quantity of water. It also appears to give a considerable quantity of alkaloids and ammonia. It will, perhaps, scarcely be a profitable speculation at present to bring this bit- umen so far for the purpose of distillation, but doubtless there are many ports into which it could be carried at a reasonable price. It is said that some has already found its way into America, for the purpose of having photogen prepared from it. France is particularly rich in deposits of bitumen, especially in the volcanic districts of Auvergne. Switzerland, Italy, Germany, Russia, Poland, in fact almost every part of Europe, contains bitumen of various degrees of consistency and value. Even in our own country there are deposits at Alfreton and other places. The Alfreton bitumen is not un- like that of Rangoon. Bitumens have been examined by various chemists, more especially by Bousingault and Yoelckel. Their results, however, require to be repeated with great care, as hitherto sufficient attention has not been paid to the purification by chemical means of the various hydrocarbons. Fractional distillation, although absolutely necessary, in order to enable bodies to be obtained of different but specific boiling points, does not do away with the necessity for elaborate purifications by means of bromine, nitric, and sulphuric acids, &c. There is little doubt that a rigorous examination of the oils procurable by distillation of the various European and other bitumens, would be rewarded, not only by scientific results of great interest, but also by discoveries of immense commercial importance. It must not be forgotten, in connection with the money value of such researches, that the bitumens yield a vei y high percentage of distillate, much greater than any of the* shales or imperfectly fossilized coals which are wrought on the large scale for the preparation of illuminating or lubricating oils. — C. G. W. NATURE-PRIXTIXG. {Xntnrsdhstdrncl; Germ.) The following description of this very beautiful process is an abstract of a lecture delivered by Mr. Heury Bradbmy at the Royal Institution: — Nature-printing is the name given to a technical process for obtaining printed repro- ductions of plants and other objects upon paper, in a manner so truthful that only a close inspection reveals the fact of their being cojiics ; and so distinctly sensililc to even touch are the impres-sions, that it is ditticult to persuade those unacquainted with the manipulation that they are an emanation of the printing-press. The distinguishing feature of the process consists, firstly, in impressing natural objects — such as plants, mosses, seaweeds and feathers — into plates of metal, causing as it were the objects to engrave themselves by pressure ; secondly, in being aide to take such casts or copies of the impressed plates as can be printed from at the ordinary cop])crplate-press. This secures, in the case of a j)Iant, on the one hand, a perfect representation of its characteristic outline, of some of the other external marks by which it is known, and even NATOEE-PEINTING. 797 in some measure of its structure, as in the venation of ferns, and the ribs of the leaves of flowering plants ; and on the other, affords the means of multiplying copies in a quick and easy manner, at a trifling expense compared with the result — and to an unlimited extent. The great defect of all pictorial representations of botanical figures has consisted in the inability of art to represent faithfully those minute peculiarities by which natural objects are often best distinguished. Nature-printing has therefore come to the aid of this branch of science in particular, whilst its future development promises facilities for copying other objects of nature, tlie reproduction of which is not within the province of the human hand to execute ; and even if it were possible, it would involve an amount of labor scarcely com- mensurate with the result. Possessing the advantages of rapid and economic production, the means of unlimited multiplication, and, above all, unsurpassable resemblance to the original. Nature-printing is calculated to assist much in facilitating not only the firsi-f■ Ditto. }- Ditto. 806 NUTRITION. Lme of the Balance of the Food. — The older opinions respecting the nature of nutrition seems to have been that the stomach and digestive organs possessed the power of assimi- hxtion, as it was termed. Although this expression might still be used in a restricted sense, the former meaning which was attached to it was of a much more extensive nature, and implied a power in the animal system which we now know is not possessed by it. Indeed, a comparatively slight acquaintance with medical writers, up to even a recent date, is suf- ficient to teach us that a belief existed that almost any species of organic matter, when s\ibjectcd to the assimilating powers of digestion, could be rendered serviceable in the sup- port of the body. The great discovery of Beccaria in 1742, in his analysis of flour, ought to have produced a greater revolution in dietetics than it appears to have done. He first observed, that if wheaten flour be washed with water on a sieve, the water becomes milky by the mechanical diff"usion of the starch, which in time subsides, while a material like glue, which is not miscible with water, remains. He termed the portion carried away by the water starch, and the soft tenacious residue he denominated gluten (now known to consist of fibrin, gluten, casein). He identified the starch with vegetalile matter, while the glutinous portion appeared to be endowed with the character usually attributed to animal matter, and this led him to propose two very simple tests by which the vegetable and animal substances, that is, matters containing nitrogen, may be readily discriminated. When vegetable, or non-nitrogenous bodies are digested in water, they do not putrefy, but ferment and yield as a product a vinous or an acid fluid. With these starch corresponds. Animal substances, on the other hand, under the same conditions, putrefy and corrupt, and afford a urinous or ammoniacal fluid. Again, distillation supplies a valuable distinguishing test of the products of the two kingdoms. Vegetable or non-nitrogenous matter, when subjected to this opera- tion, yields an acid product, and a heavy black oil, similar to pitch. Such are the characters of starch. Gluten, like animal or nitrogenous bodies, affords an alkaline spirit — a volatile alkaline salt (carbonate of ammonia), first a yellow, then a black oil, and finally there is left, by intense heat, a black spongy matter (charcoal), which in an open fire becomes a white insoluble earth (bone earth). These remarkable observations struck Beccaria with surprise, as he found no traces of any such results in previous writers. For when he had discovered gluten by the iiimple process already detailed, it appeared to him so identical with animal matter that, if he had not himself extracted it from wheat, he should have mistaken it for a product of the animal world. {Hist, de VAcad. df Bofo(/ne. Collect. Acad. x. 1.) These views, which are in exact consonance with the most recent ideas entertained by chemical physiologists, appear to have produced little fruit, although the question put by the author, "Are we composed of other substances than those which serve for our nourishment?" dis- tinctly exhibits the view which he took of the subject. Duiing the present century, a large amount of experiment has clearly demonstrated that animals cannot subsist on starch, s)igar, or other foods destitute of nitrogen ; and therefore the inference was fairly deduced that the animal system possessed no power of assimilating nitrogen from the air. {Magendie.) Furtlier consideration led to the conclusion that milk constitutes the type of what nutriment should be, since it is supplied for animal support by nature at the earliest period of human existence (Prout), and contains nitrogenous matter, oil, and sugar. Afterwards, experi- ments were made to determine the amount of nitrogen in food, and the relative value of nutriment was tabularly stated, in dependence on the ratio of nitrogen present in each species {Bowmbuiault, An7i. de Chim. Ixiii. 225, 1836), a method which has been super- seded. It was svibscquently inferred that nitrogenous matter supplied the waste of the muscular tissue, while the non-nitrogenous constituents of the food served for respiratory purposes, or the production of animal heat by obviating the too rapid transformation of the muscular elements of the body. {Liebig., Orc/anUchc Chemie, 1842.) This was the true key to the solution of the problem as to the function of the nitrogenous and non-nitrogenous food, and it laid open a wide field for inquiry in reference to the application of rational systems of dieting to the animal system. For example, it was found in a series of experi- ments conducted for the British Government in 1845, that in a stall-fed cow in one day, taken from an average of several months, the amount of food conveyed into the circulation of the blood of the animal, was 14-56 lbs. weight, and when the nature of this mass of nutri- ment was subjected to chemical inquiry, it appeared that 1-50 lbs. consisted of nitrogenous matter, and 13 lbs. of non-nitrogenous food. When the relation between these two quanti- ties is calculated, it results that the nitrogenous is to the non-nitrogenous food as 1 to 8.33, as in the case of an animal at rest. This observation led to researches into the relative constitution of food as employed by different nations ; and the deduction was made that it is a law of natuie that animals, under the different conditions of rest and exertion, require food in which the relation of the nutrient or nitrogenous food is different in reference to the non-nitrogenous or heat-producing (calorifiant) constituent: — that the animal system may t)e viewed, as, in an analogous condition to a field, from which diiferent crops extract different amounts of matter, which must be ascertained by experiment ; — an animal at rest consuming more calorifiant food, in relation to the nutritive constituents, than an animal in full exercise. From the analyses then instituted the following table was constructed. NUTRITION. 8or Approximate relation of nutritive or nitrogenous to calorifiant matter . — Kelation of Nutritive to CaloritiaDt Matter. Milk food for a growing animal lto2 Beans 1 " 2^ ;Pp^ ^ I 1 " 3 Linseed ) Scottish oatmeal - - - - - - - 1 " 5 Wheat flour 1 f 1 " Y Semolina - I p^^^ ^^^ ^^ ^^^^j ^^ ^^^^ . J ^^ Indian corn i " c Barley - J I Potatoes 1"9 East India rice - - 1 " 10 Dry Swedish turnips 1"11 Arrowroot 1 Tapioca [• 1 " 26 Sago ) Starch 1 " 40 These proportions will consequently vary considerably according to the richness of the grain or crop, and hence similar tables which have been subsequently published by others will be found to differ in some of the details from the preceding data ; but the facts now stated — given as approximate — are probably as good averages as could be selected. — R. Z>. Thompson, Mcdico-Chirurgical Trans, xxix. and Experim. Researches on the Food of Anhnals, 1846, p. 162. A consideration of the nature of the relations exhibited in this table is sufficient to afford an explanation of many practical results in the subject of diet. Thus in the young of the mammalia — including the human race — the heat-forming or non-nitrogenous food is only two or three times greater than that of the nitrogenous food which is the supporter of the muscular tissue of the body, because the child requires a larger amount of matter to repair its daily waste, and likewise an additional portion to enable it to increase in bulk. Nature has so arranged that, in the milk of the mother, every three or four ounces of the solid particles of that fluid shall supply one ounce of nitrogenous material. When we compare this result, which is a fact independent of all theoretical considerations, with the condition of the class of starches at the close of the table — known under the names of arrow-root, tapioca, and sago — we see, that to supply these to children would be to deprive them of the possibility of obtaining the requisite nourishment demanded by the wants of their systems ; since to communicate one ounce of nitrogenous matter to them, it would be necessary that they should swallow 26 ounces of starch, a proceeding which, upon mechani- cal considerations alone, would be impracticable. Beans and peas have been found much more effective in supporting the strength of animals subjected to hard labor than grass or other soft fodder ; and the reason for this on the principles under review is obvious. A cow weighing about 1,000 pounds was found to introduce into its system 15'28 pounds of the solid portions of grass daily ; but this was extracted from 100 pounds' weight, of fresh grass, and contained r56 pound only of nitrogenous matter, and 13'1 of heat-forming or respiratory food. To convey this large mass of nutriment into the stomach required the action of the primary organs of digestion during the whole day ; while to have introduced a similar amount of nitrogenous matter in the shape of beans, not above 20 pounds would probably have been necessary. Thus by subsituting the concentrated form of beans for the bulky grass, a great saving of time is effected in conveying the digestive materials into the current of the blood. The bulky nature too of grass — f^rora 100 lbs. of which only 15f pounds of nutritive matter can be extracted — affords an explanation of the more complicat- ed nature of the stomachs of ruminant animals than of the luiman family, which practical experience, or instinct, as some would term it, has taught to select more concentrated forms of food. Thcprimary and original food of man, whatever speculators may say to the contrary, is milk, a fluid of purely animal origin. If those who are to regulate diet are not guided by scientific knowledge, and do not exercise their judgment, they might be inclined to draw from this fact tiie inference, that the proper nutriment of man is animal food. This dediic- .tion might be defended with some show of reason to the exclusion of a vegetable diet. But observation having proved that animals can subsist upon a vegetable as well as upon an animal regimen, and scientific research having satisfactorily demonstrated that the constitu- ents of the two kinds of nutriment, when well selected, are identical, the one-sided position must yield to the light of knowledge. It will be now from these details, in some measure, understood how it happens that for all conditions of society, vegetable food may not be advi.sable ; and that vogctarianism, while it may be applicable in some instances, would be prejudicial in other individual cases. The 808 NUTRITION. poetical and merciful sympathies of Pythagoras it is impossible altogether to set aside, ahhough it is unnecessary to echo tlie sentiment that " the man of cultivated moral feeling shrinlis from tlie talking the life of the higher grade of animals, and abhors the thought of inflicting pain and sheddhig blood ; " for even the Greek philosopher, although he objected to slay cattle lor the purposes of human food, sacriticed, in a tit of enthusiasm, without any compunction, one hundred oxen in commemoration of his discovery that a square on the hypothenuse of a riglit-angled triangle is equal to the sum of two squares on the base and the perpendicular. Indeed, such a cruel result of a scientific discovery has appeared to his admirers so inconsistent, as to induce them to suggest that the oxen were made of wax. It is more probable tliat, as in modern times, other causes had tended towards a vegetarian conclusion. But his arguments may be heard: "Forbear, mortals, to pollute your bodies with abominable food. Wild beasts satisfy their hunger with flesh, although not all ; for the horse, flocks, herds, feed on grass. But "those which have a wild and ciuel temper, Arme- nian tigers, angry lions, bears, and wolves rejoice in bloody food. What a wicked crime it is that bowels should be buried in Ijowels, and that one greedy body should fatten on another crammed into it, and one animal should live by the death of another!" — Ovid, Metcwiorph. xv. 2. A practical application of the law involved in the table to the nourishment of horses will now be understood. If we represent the amount of muscle removed from the body of a horse to be 2 lbs. per day, while the amount of food consumed in the production of heat is 12 lbs., it is obvious that, to make up for this loss, we should never think of giving to the animal food containing 2 lbs. of albuminous or muscular matter and 52 lbs. of non-nitrogen- ous or heat-forming matter, such as sago; neither should we give a diet containing 2 lbs of albuminous materials and 22 of calorifiant ingredients, such as turnips; but we should endeavor to administer nourishment which contained as nearly as possible the ingredients which the animal's consumption required. This object would be nearly attained by the use of oats, which would give ior every 2 Ib.s. of muscular material, 10 lbs. of heat forming constituents; or by barley 2 to 14. A mixture, then of the two grains would supply the nourishment required by the animal, or the same result would follow by the employment of beans and hay. The principle of the arrangement of the food being understood, the nature of the nutriment can be easily calculated for the different conditions in which the animal may be placed. A continuous study of the table brings us to oatmeal, which constitutes, even at the present day, an essential element in the support of the Scottish peasant. W^heat is no doubt cultivated to a greater extent than formerly, in northern latitudes, but from the analyses which have been published, it ajipears to be an undoubted fact that the amount of nitrogen increases, within certain limits, in this species of the cerealia as the plant advances from the equator. But one cause of the high nitiogenous position held by oatmeal is, that as it is usually prepared, it retains much of the bran, which is rich in nitrogen ; while in the pre- dominant form of wheat-flour this ingredient is in a great measure removed. When, however, the bran is retained in the flour, as when the entire wheat-seed is ground up and not sifted, the superiority of the nutritious value of oatmeal over wheat-flour has not been demonstra- ted. The substance termed semolina in the table, consists of bruised wheat from the south of Europe, and corresponds with the manna croup of the north of Europe, and the soojee of India. Illustrations of the fatal effects of this practice have been afforded by feeding calves on sago, a form of farinaceous matter, as exhibited by the table, which is artificially dis- turbed in its natural equilibrium. For it will be remembered that arrow-root, tapioca, and sago, as they occur in commerce, are the starches of natural flours which have been washed by repeated applications of water, until they have been to a great extent deprived of their nitrogenous matter, and of their saline ingredients. Calves fed on this form of food, have been observed to become most ready victims to passing epidemics. {Smith of Dcanstove.) For a brief period they seem not to suffer, but on the approach of disease they were readily subjected to its action, and rarely recovered. The same reasoning will apply to the human species. For if a child were fed on milk entirely (its composition being 1 nutiitive to 2 heat-forming, the proper blood salts), and throve as nature intended it should do on this species of aliment, could we expect that the inf\xnt would be equally nourished, >vhen a portion of this type of food was replaced by arrow-root, containing 1 nutritive to 26 of calorifiant material, without any saline ingredients rcfiuiied to produce blood? To expect such a result would be opi)osed to experience and to all analogy. From the table we may infer that the food destined for an animal in full exercise, should range between milk and wheat- flour, according to the nature and extent of the demands upon the system. Milk may there- fore be employed with a certain amount of the cerealia with probable advantage. When the food is preserved by nature, by means of combining water, as in succtdcnt vegetables, from the severe effects of the vicissitudes of the atmosphere, the most efficient nutriment is aflbrded to the inferior animals. This is shown in the following table, where an average is given of the products of two cows, in milk and butter, by dift'erent species of aliment. The largest amount is obtained from grass, which preserves its equilibrum most firmly during Butter in Nitrosen in Food 5 days. in 5 daj-s. lbs. lbs. 3-50 2.32 3-43 3-89 3-20 3-34 3-44 3-82 3-48 414 3-72 5-27 NUTPJTIO:?^. 809 the changes of the seasons, while hay and cereal crops, from their want of succulence, and therefore of protection from the rain and fermenting influences, are less influential in ett'ect- ing a steady product. Milk in 5 days, lbs. 1. Grass - - - 114 2. Barley and hay - 107 3. Malt and hay " - 102 4. Barley, molasses and hay 107 5. Barley, linseed, and hay 108 6. Beans and hay - 108 It had been found by experiment, that, not only in hay-making is the coloring matter of the grass removed or altered, but, particularly in moist districts, the sugar or heat-forming portion of this form of provender is washed out.by the rains or destroyed by fermentation, wliile a certain proportion of the soluble salts absolutely refjuired for the production of animal blood and milk is also removed by every shower which falls during the drying of the hay. In this table, the butter and milk of the cow may be supposed to represent the increase of bulk which a gi'owing animal sustains during its infant years; while the richness of these forms of dairy -produce are the well-recognized tests of the value of the soil and pasturage upon which the animals have browsed. By a comparison of the relation of the different kinds of cerealia we may improve one species by mi.xing it with another. By mi.xing one-third of Canada flour with two-thirds of Indian corn, a very good loaf is produced, and when equal parts of flour and oatmeal, or of barley, or of pea-meal are employed, a nourishing bread is formed. Beneficial results have also followed from the admi.xturc of two or three different kinds of grain, and many of these forms of bread might be substituted with advantage for wheat flour in peculiar conditions of the system. The superior advantage of good wheat flour depends on the presence of gluten, an adhesive nitrogenous principle, which, during fermen- tation by the resistance which it presents to the escape of the carbonic acid, engenders that vesicular spongy condition which is considered the test of a good loaf From the absence of this substance in other kinds of grain, they are of themselves incapable of affording a spongy loaf, and hence the presence of wheat floiu- is essential in all well-raised bread. A loaf may be made of equal parts of oatmeal and flour, which when fermented will be highly spongy. It is advisable in such a case to use foreign flour, which contains a larger propor- tion of adhesive gluten than is found in the wheat flour grown in our northern climate. It may be objected that the recommendation of such mixture is a direct invitation to bakers to adulterate their flour. But such mixtures are admitted by law with the provision that the letter M be affixed by the baker to the loaf. Indian-corn bread may be baked of good quality by a smaller admixture of flour than is necessary when oatmeal is the other ingre- dient. For this purpose it should be reduced to a fine meal, in smaller particles than is practiced in the United States. It may then be mixed with one-third its weight of i)est floirr, and be fermented in the usual way. When thus baked, the best Indian-corn bread is always dark colored, and cannot be made much lighter than coarse wheat bread. The shade of color is yellowish. When Indian-corn bread appears white, the conclusion to be drawn is that the mixture consists of more than one-third of wheat flour. Even wlien one-half its weight of wheat flour is added to it, Indian-corn exhibits in the mixture its characteristic dark tint. See Bread. The position which potatoes hold in the nutritive scale, shows that although they are frequently used in the mode of preparing bread by fermentation, no advan- tage would be gained by augmenting their amount, since the aliment would thus be render- ed more dilute and the statement of the poet confirmed : — " Bread has been made (indifferent) from potatoes." — Stjron. At the present day the Xew Zealanders are affected, to the extent, in some districts, of 20 per cent., in others of 10 per cent., with external marks of scrofula, a fact whit'h was not observed by Capt. Cook. This disease is theiefore inferred to be a modern innovation, brought about by the natives having lived since Cook's time on potatoes, which have super- seded fish and pig's flesh in a great measure. It is only necessiuy to sec a child after a mouth's residence in the house of a European, to have an indication of the magic influence better diet would have on the whole race. The puny limbs of the young savage grow stout, the protuberant belly disappears, and traces of red blood can be seen through the nut-col- ored skin of his infant face. — A. S. Thdmsini'a Xrw Zralntid, i. 2ir>. Further support of the law enunciated has been afforded l)y subsequent experiments {Freseinus, Knapp, Plai/fnir, Licbi(j). " A glance at these relations is sufficient to convince us that in choosing his food (when a ciioice is open to him), and in mixing the various articles of diet, man is guided by an unerring instinct which rests oir a law of nature. TJiis law pre- scribes to man as well as to animals a proportion between the plastic ami non-nitrogenous con- stituents of his whole diet, which is fixed within certain limits within which it may vary accord- 810 NUTRITION". ing to his mode of life and state of body. This proportion may, in. opposition to the law of nature and iu.-;tinct, be altered beyond these limits by necessity or compulsion, but this can never happen witiiout endangering the health and injuring the body and mental powers of man. It is the elevated mission of science to bring this law of nature home to our minds; it is her duty to show why man and animals require such an admixture in the constituents of their food for the support of the vital functions, and what the influences are which deter- mine in accordance with the natural law changes in this admixture." {Liebig, Fam. Letters on Cliem'tHtry, 1851, p. 362.) It has been shown that when a French soldier is fed on 1 lb. h^h oz. of bread, he consumes in this ration 1 part of nitrogenous to 4| of non-nitrogenous material (Knapp), and that when pigs were fed on potatoes no augmentation could be detect- ed in their weight. An increase was observed when the diet of the animal was potatoes, butter-milk, whey, and kitchen refuse, but the greatest improvement took place under what was termed a fattening fodder, consisting daily of 9'74 lbs. potatoes; ground corn 9 lbs. ; rye- meal "64 lbs. ; peas, '68 lbs. ; butfer-milk, whey, and kitchen refuse "92 lbs. {Boussingaidt). In these different modes of dieting, the following were the relations of the constituents of the food: Nitrogenous. Kon-nitrogenous. Potatoes 1 to 8| Mixed food . . - . i " v;,, Fattening fodder - - - 1 " 5^ The German farmer renders the proportion more nearly allied between the proximate prin- ciples of the potato, by fermenting and distilling from them a spirit, and giving the residue thus supplied with a le.ss proportion of heat-forming material to his cattle. It has been supposed in other countries that the German agriculturist is a distiller. On the contrary the production of spirit is a result of what he has found to be, by experience, a valuable method of improving the alimentary character of the potato {Knapp). All of these expla- nations have been deduced since the law of the equilibrum of the food detailed above was detected. The tables on the next page are illustrations of the same law. In these tables the ounces of the original are calculated as grammes, and the last column gives the relation of the nitrogenous or flesh-forming part of the food, to the non-nitrogenous or heat-producing ingredients of the aliment, instead of, as in the original, the proportion between the carbon of these constituents of the food being estimated. The table is read thus : an English soldier consumes weekly 11,703 grammes (a gramme equal to 15'44 grains) of food. In this food 1,119 grammes are nitrogenous or flesh-forming matter ; 3,937 non-nitro- genous or heat-producing material; 152 mineral substance; the organic matter containing 2,219 grammes carbon. The relation of the nitrogenous to the non-nitrogenons matter is as 1 to 3 "50. From this table the results have been deduced that soldiers and sailors consuming 35 ounces of nitrogenous or flesh-forming food weekly, and 70 to 74 ounces of carbon, the proportion of the carbon in the flesh-forming to that in the respiratory or heat-forming iood is as one to three. Older persons require only 25 to 30 flesh-forming matter weekly, and from 72 to 78 respiratory food ; the relation of the carbon in these is as 1 to 5. Bos'S of from ten to twelve years of age require 17 ounces of flesh-forming matter, the relation of the carbon in the flesh-forming to the heat-producing aliment being as 1 to 5i. In work- houses and jails, less heat-producing matter is consumed, in consequence of the shelter and heat supplied artificially to the inmates. In prisons, where hard labor is in force, the con- sumption of flesh-forming or nitrogenous nutriment increases. It has been estimated that in a man weighing 140 lbs., the weight of the flesh-forming matter of the blood is 4 lbs., that of tlie muscular ti.ssue 27+ lbs., and in the bones 5 lbs., making a total of 364 lbs., and that in the course of 18 weeks these 364 lbs. are introduced into the system. (Plaiifair, New Edin. Phil. Journal, 1854, 56,262.) The author of this elaborate and valuable table has justly remarked that the old mode of estimating the value of dietaries, by merely giving the total number of ounces of solid food used daily or weekly, and quite irrespective of its com- position, is most erroneous; and he quotes an instance of an agricultuial laborer, in Glou- cestershire, who in the year of the potato famine subsisted chiefly on flour, consuming ]()3 ounces weekly, wliich contained 26 ounces of flesh-forming matter. Wiien potatoes became cheaper, he returned to a potato diet, and now ate 321 ounces weekly, although they con- tained of true nutriment only about 8 or 10 ounces. A comparison of the six pauper dietaries formerly recommended, with the difference between tlie salt and fresh meats diet- ary of the sailor, &(?., have no relation in equivalent nutritive value, but merely rely on al)solute weight alone. It is l)y such dietaries, where the proper balance of the constituents is not preserved, tiiat, although the appetite may be satisfied, the waste of the system is not adequately repaired. The health may appear not to be affected in the absence of epidemics, but, under such a dietary as that alluded to, a maximum of labor cannot be obtained from a workman ; a frail constitution is engendered, which acts as a fertile soil to miasmata of various kinds. Tliese seeds ofdisea.se taking root, are rapidly developed into maladies, like the rank fungi of damp and dismal cellai-s. NUTKITION. 811 Weekly Con- sump- tion. Dietaries of Soldiers and Sailors. English soldier - _ - " " in India - - " " sailor (fresh meat) - " " (salt meat) - - - Dutch soldier, in war - - - - '<■ " in peace - • " French soldier - - - - " Bavarian soldier - - • - ■ Hessian soldier - - - • ■ Dietaries of Children. Christ's Hospital, Hertford - " London - Chelsea Hospital boys' school Greenwich Hospital " Dietaries of Aged Persons. Greenwich pensioners - Chelsea " - - - Gillespie's Hospital, Edinburgh - Trinity Hospital " Dietaries of Aged Poor. 1st class ------ 2d " 3d " 4th " 5th " 6th " 3fean of all Enr/lish counties St. Cuthbert's, Edinburgh - City poorhouse " ... Dietaries of English Prisons. 2d class, above 7 not above 21 days - 3(j " 21 " 6 weeks' hard labor . . . - 4th, Ith, 8th classes, above 6 weeks' not above 4 months' liard labor 5th class, above 4 months' hard labor - Bengal Prisons. Without labor With labor - - - - Contractor's insufficient diet BoMnAY Prisons. I All classes, without hard labor - With hard labor Arctic anp other Dietaries. Esquimaux Yaout ..---- Boschesmen Hottentots ------ Farm laborers, Gloucestershire - " Dorsetshire - - - " Dharwar, Bombay — re- turn in Bombay Prison Dietaries - Grms. 11703 9080 9350 8978 6130 11857 10742 7492 13096 6687 7488 7585 7151 8328 10278 4829 5944 5418 3312 Nitro- genous Matter. Grms. 1119 1057 1078 1274 1090 759 1029 652 712 631 534 401 570 757 905 651 G08 626 463 488 595 479 454 681 458 412 Non- nitro- genous Matter. Mineral Constit- uents. 6393 9144 8405 10092 6935 9464 5185 47a 565 649 628 571 872 393 5634 667 6935 1103 5065 3548 7740 3093 1777 1323 825 631 Grms. 3937 3195 3185 4092 3160 3306 3955 3161 4210 1897 2378 2888 2685 3784 3487 2858 3014 2743 2773 3092 3617 2988 2725 3065 2766 1547 6749 434 Carbon. 3463 3827 3900 4042 5051 5917 4209 3142 3987 39628 19814 11393 12384 3299 2243 4280 Grms. 152 74 98 187 57 128 143 103 76 88 183 81 109 144 73 104 101 89 121 123 111 88 102 54 107 125 156 131 64 92 40 63 76 Relation of nitro genous to non- nitro- genous Matter. 34 30 Grms. 2219 2053 2184 2706 2293 2191 2639 1933 2384 1213 1453 1785 1637 2242 2416 2210 1774 1681 1582 1716 2101 1694 1535 1796 1454 975 As 1 to 3-50 3-02 2-95 3-69 2-90 4-35 3-84 4*85 5-91 3-57 K 1834 2091 2162 2270 2364 2819 4-45 7-20 4-71 4-87 3-85 4-39 4-95 4-38 5-99 6-33 6-08 6-24 6-00 4-50 6-04 3-75 7-34 6-77 6-00 6-43 8-85 6-78 1899 10-71 2130 2800 34830 29907 17182 18699 2323 1601 1905 2-08 3-61 5-12 6-46 6-41 9-30 3-97 3-55 9-86 812 NUTRITIOX. Fat animal. Lean animal - 12-5 12-8'7 - 33- 25-3 - 3- 45 - 51-5 57-33 When the constitution of the food is compared in its relations of muscular to fatty mat- ter, with the proportion of these ingredients deposited in animals, the result .is of interest. Carefully conducted experiments on the large scale upon animals have shown, that in fat animals killed and carefully analyzed after death, the carcass of the fat ox contained 1 part of nitrogenous matter to 2^ fat ; in that of the fat sheep the relation was 1 to 4 ; in that of the very fat sheep, 1 to 6 ; and in the moderately fat pig, 1 to 5. In the lean sheep the proportion was 1 to 1+; in the lean pig, 1 to 2. The average composition of such well fat- tened and lean animals was found to be nearly Nitrogenous matter ... Fat Mineral matter - • • - "Water . . - - , 100-00 100-00 It was found by an analysis of some of the most important animals fed and slaughtered as human food, that the entire bodies, even when in a reputed lean condition, may contain more dry fat than dry nitrogenous substances. Of the animals ripe for the butcher, a bul- lock and a lamb contained rather more than twice as much dry fat as dry nitrogenous mat- ter; while in a very fat pig and sheep, the proportion was 1 muscular matter to 4 fat, and in a moderately fat sheep the fat was three times greater than the nitrogenous matter. — Zaices and Gilbert, Proc. Royal Society, No. 32,348. — June, 1858. Use of Fermented Liquid.'i in Nutrition. — In the very earliest periods of human history wine appears to have been known, and to have been of the same nature with that which we now use, as the Hebrew term employed to designate the stimulating liquor indicates it as being derived from a fermenting origin, (Pareuit. Antiq. Ileb. 396.) This, together with its wide-spread use, has frequently been considered as an argument in l\ivor of its necessity. But its ubiquity cannot be substantiated. The native Indians of North America, amount- ing to some millions in number, were unacquainted with fermented products until they were visited by the white man, {Catlin.) When the Spaniards. first visited South America, they were astonished at the constitutional temperance of the natives, which, in their opinion, far exceeded the habits of the most mortified hermits, {Robertson, iv.) In Patagonia, within the last 200 years, the inhabitants, when offered a bottle of brandy, would not drink, {Sir J. Karhrough, in 1669, 8vo. 1711, p. 50.) If we refer to Africa, we have the authority of the great traveller who has penetrated into the interior of that mysterious continent, that, true to their faith, the Mohammedans " drink nothing but water," [Park,) and it is only among the Pagan negroes who have frequent intercourse with the coast in consequence of these being the reservoirs from which slavery emanates, and in such senii-civilized towns as Tripoli, that religion is placed in subjection to inebriating indulgences, and that " drunken- ness is more common than even in most towns in England," (Lyon.) It is true that the ancient Gauls and Germans, who, however, were somewhat civilized, made use of beer, but whether they did so habitually, or to excess, before they were contaminated l)y Roman cus- toms, seems unlikely. Certain it is, that they had no wine of their own. Tiie Gauls pur- chased their wine chiefly from Italy, and were exceedingly fond of it, {Diodori'n,) and hence they are said to have been invited into that country by the delicacy of the Italian wines, {Livy, V. 33.) Even among the Romans, however, in the virtuous days of the RepuVjlic, strong drinks were not universally in favor, since it was fashionable, in order to make wine keep, to boil it down to one-half, (Virr/il,') or one-third, {P/iny\) in other words, to distil away all the alcohol it contained. All the circumstances, indeed, with which we are ac- quainted, seem to support the view of the historian, that " it is in polished societies where intemperance undermines the constitution," (Robertaon.) These facts seem to prove that alcohol is not a necessary of life. It remains to consider what its influence is upon the sys- tem. When fluids containing alcohol are introduced into the body of animals, the amount of carbonic acid evolved from the lungs speedily begins to dimini,sh. The influence of even a small portion of wine begins to be appreciable in a very short space of time after it has been swallowed, so that we infer its power in this respect to be almost consentaneous with its arrival in the stomach. Alcohol itself possesses a similar effect, and the use of porter is attended by the same results. Numerous experiments have demonstrated that alcoliol in every state, and in every quantity, uniformly lessens, in a greater or less degree, the quan- tity of carbonic acid elicited according to the quantity and circumstances under which it is taken. When taken on an empty stomach, its eff'ects are remarkable ; the depression is greatest almost instantaneously ; after a short time, however, the powers of the constitution appear to rally, then it sinks again, and afterwards .slowly rises to the standard. That the action of the alcohol in these cases depends on its influence on the nervous system, and not on its chemical action, is obvious from the fact that strong tea acts in a similar manner, and with the same degree of rapidity ; three ounces of strong tea, in five minutes aft^r being swallowed, depresses the amount of carbonic acid progressively, {Prout, 1813.) Other ex- NUTRITION". 813 periments bear testimony to the wonderful efifect of alcohol on the nervous system. Two miners of alcohol, when injected into the stomach of a rabbit, rendered it immediately insen- sible, just as if tlie animal had been violently struck on the head. Two di-achms placed in the stomach of a cat, instantly made it struggle violently and fall on its side perfectly mo- tionless and insensible. It is remarkable, too, that the eftects of alcohol, and of injuries, more particularly concussion of the brain, so closely resemble each other, that the most accurate observer cannot often distinguish them, except from the history of the case, (Sir B. C. Brodie.) When alcohol is introduced in excess into the system^ the arterial blood appears to retain the venous condition, and thus asphyxia may be produced, (JJouchardal.) Alcohol, it is affirmed, has been detected in small proportion in the air exhaled from the lungs, and also in the blood of drunkards, while a considerable portion of acetic acid, one of the products of its combustion, has been observed in the blood after the use of this fluid, (ib.) Tiiese views, therefore, tend to the conclusion that alcohol, in all its forms, produces an alteration in the usual phenomena consequent upon digestion ; that this influence is anal- ogous to that of tliose causes which produce depression of the nervous centres, and there- fore its employment by preference as a heat-supplying agent to the animal system in cases of health, is a procedure involved in very great doubt. The argument in favor of the calorifiant nature of alcohol is, that as it disappears in the system it acts as an element of respiration, and although its constituents do not possess by themselves the property of com- bining with oxygen at the temperature of the body, and forming carbonic acid and water, yet it acquires, by contact with bodies susceptible of this combination, this property in a higher degree than fat, &c., {TAchiy.) If, then, alcohol be thus capable of conversion into carbonic acid and water with facility, how are we to explain the fact that alcohol diminishes the amount of carbonic acid in the expired air ? The answer has been, that as alcohol con- tains a large amount of hydrogen, which, by union with the oxygen of the air, passes off from the lungs in the form of vapor of water, the diminution of carbonic acid is a neces- sary result of the use of this stimulant. But there is a remarkable fact which appears to throw doubt on this view, viz., that in addition to the analogous and instantaneous action of tea, as long as the effects of alcohol are perceptible to the feelings of the individual who has swallowed it, the quantity of -carbonic acid is below the standard. The effects of drink- ing go off with frequent yawnings, and with a sensation as if awakening from a sleep. Under these circum.stances the quantity is generally much above the standard, and hence it would seem that the system is freeing itself from the retained carbon, [Prout.) The phe- nomena of yawning, sighing, &c., appear to have evidently the effect of throwing off a quantity of carbonic acid retained in excess in the system, since sleep and depressing pas- sions seem to operate by diminishing the amount of carbonic acid. There may be various reasons, too, for inferring that alcohol is not thrown off in the form of colorless, odorless, gases by tlie lungs. The offensive ethereal smell retained in the breath of the drunkard for many hours after the introduction into the stomach of the cause of his inebriation, seems to favor the view that other products besides carbonic acid and the vapor of water result from the use of alcohol. That alcoliol does not occupy a very high position as a calorifiant agent, is evident from its comparative operation in heating the body when cooled and de- pressed by external cold. Hot fluids are familiarly known to all to be much more efficient in raising the heat of the body than raw spirits or strong fcrme7ited fluids, whicli have a depressing action unless combined with hot fluids. The influence of the use of spirits has been tested in tlie army, and it has been found in India, that when a regiment consumed from 10,000 to 14,000 gal- lons, the mean annual mortality was TO, and when the amount was reduced to '2,00ii to 3,000, t!ie mortality fell to 21, out of the same strength. An interesting experiment has been in operation during the last 20 years in the United Kingdom Provident Institution. During that i)eriod this society has insured a distinct section of abstainers who number above 5,000, and it has likewise a more numerous section of the general public. During the first 6 j'ears, out of 2,060 members, only 18 died, equivalent to a loss of '9 per cent., while the office of the Society of Friends, who are distinguished for their care of health, lost in the con-esponding period of their history 3 '3 per cent. The most recent report from this institution, after 1.5 years' existence, gives a return of 19 per cent, of profits in favor of the abstainers, over the section of non-abstainers ; although that division likewise con- tains many individuals of the latter class. Influence of Tea and Coffee in Nutrition. — The experiments already referred to indicate that tea delays the regular changes of the body of animals, since the carbonic acid exhaled from the lungs declines in quantity under the influence of tea, {Front, \^,\'^.) Coffee, from its containing the same principle, might be inferred to be possessed of a similar action, and this has been found to be the case ; but it has been found, in addition, that a decoction of coffee communicates greater activity to the circulation and nervous system. The delay which it effects in the metamorphosis of the tissues appears to he occasioned l)y the cmpy- reumatic oil of the berry, which likewise produces increased action of the sweat pores, of the kidneys, and an accelerated motion of the intestinal canal ; while the effects of calfcin 814 OIL OF VITRIOL. in excess are increased activity of the heart, headache, delirium, &c., {Lehmaixn^ 1853.) Coffee and tea, as usually employed, appear therefore to act as stimulants and as agents Ijy which the conversion of the solids of the body into soluble and gaseous products is consid- erably delayed. Their influence is analogous to that of alcoholic fluids when these are taken in moderate quantities, although there is no evidence that they are capable of producing organic disease, such as inevitably attends the consumption of increased doses of alcoholic fluids. The Turcomans employ tea in their wanderings as an article of nutriment, and have discovered, by long experience, what has been confirmed by chemical research, that the leaves of tea contain a large amount of nitrogenous matter, which is not, however, dissolved in the usual process of infusion. One ounce of tea-leaves and an equal weight of carbonate of soda are boiled by the Turcomans in a quai-t of water for an hour. The licjuor is then strained and mixed with ten quarts of boiling water, in which an ounce and a half of com- mon salt have been previously dissolved. The whole is then put into a narrow cylindrical churn along with butter, and well stirred with a churning-stick till it becomes a smooth, oily, and brown liquid, of the color and consistence of cliocolate, in which form it is trans- ferred into a teapot, {Moorcroft.) The soda has the effect of taking up the cassein or curd, a most nutritive nitrogenous compound, and which is present in large ((uantity. Influence of Tobacco and Opium on Nutrition. — It has been observed in fiivor of the practice of smoking tobacco, that even the most primitive tribes indulge in this practice. If it were a correct observation, the practice may be pronounced to be a savage one, and to be connected with the conditions of savage life. The North American Indians all smoke, but when uncontaminated by intermixture with the whites, tobacco is unknown to them. The material which they employ is the prepared bark of a species of willow. The presence of such products of combustion in the system appear like tea and coffee, which have also been discovered in primitive nations to delay the degradation of the tissues and husband the food. The American Indians, who live entirely upon animal food, and who have impressed on them a restless and wandering existence, from the nature of their food — from the diffi- culty experienced in obtaining animal heat — from the metamorphosis of the nitrogenous tissues — use the smoke of vegetable matter to make their food last longer. Tobacco and opium when smoked appear to have a similar action, but they likewise influence the nervous system and occasion a stimulating influence, which is apparent in the vivacity of the eye, particularly with opium as it is smoked in China. The practice of opium-eating, as in use among the Turks and the islands of the Indian Ocean, is totally distinct in its physiological results ; a wild inebriety being often produced, which, if persisted in, conducts to a lament- able end. In a case which occurred to us^ the liver was entirely destroyed by fatty degen- eration.— R. D, T. o OIL OF VITRIOL is the old name of concentrated ScLPHrRic Acid. OILS. Clievreul considers all the oils to be composed of two, and sometimes three dif- ferent species, viz., stearine, margarine, and oleine ; the consistence of the oil or fat vary- ing as either of these predominates. These bodies are all compounds of r/hicerine, with a fatty acid. At all ordinary tempeniturcs oleine is liquid ; margarine is solid, and melts at 11(3' F. Stearine is still more solid, and melts at about 130' F. The two latter may be prepared from pure mutton fat, by melting it in a glass flask, and then shaking it with sev- eral times its weight of ether ; when allowed to cool, the stearine crystallizes out, leaving the margarine and oleine in solution. The soft mass of stearine may be strongly pressed in a cloth, and further purified by recrystallization from ether. It forms a white friable mass, iiisolutile in water, and nearly so in cold alcohol ; but boiling spirit takes up a small quan- tity. It is freely soluble in boiling ether; but, as it cools, nearly all crystallizes out. Margarine may be prepared from the ethereal mother-liquor, from which the stearine has separated, by evaporating it to dryness; the soft mixture of margarine and oleine is then pressed between folds of blotting-paper ; the residue again dissolved in ether, from which the margarine may now be obtained tolerably pure. It very much resembles stearine, but, as above-mentioned, has a lower melting point. It is rather doubtful if oleine has ever been prepared in a perfectly pure state, the sepa- rntion of the last particles of margarine being very diflicult. It may be obtained by sub- jecting olive oil to a freezing mixture, when the margarine will nearly all separate, and the .supernatant fluid oil may be taken as oleine. Oleine may also be procured by digesting the oils with a quantity of caustic soda, equal to one-half of what is requisite to saponify the whole ; the stearine and margarine are first transformed into soap, then a portion of the oleine undergoes the same change, l)ut a great part of it remains in a nearly pure state. This process succeeds only with recently-expressed or very fresh oils. The fat oils are completely insoluble in water. "When agitated with it, the mixture be- comes tuibi'i, l);it if it be allowed to settle the oil collects by itself upon the surface. This OILS. 815 method of washing is often employed to purify oils. Oils arc little soluble in alcohol, ex- cept at high temperatures. Castor oil is the only one which dissolves in cold alcoliol. Ether, however, is an cxccUcut solvent of oils, and is tlierelore employed to extract them from otlier bodies in analysis ; after which it is withdrawn by distillation. Fat oils may be exposed to a considerably high temperature, without undergoing much alteration ; but when they are raised to nearly their boiling point, they begin to be decom- posed. Tlie vapors that then rise are not the oil itself, but certain products generated in it by the heat. These changes begin somewhere under 600" of Fahr., and require for their continuance temperatures always increasing. The products in this case arc the same as we obtain when we distil separately the differ- ent constituents, (stearine, margarine, &c.,) that is to .say, a little water and carbonic acid, some gaseous and liquid hydrocarbons, some solid fatty acids, (particularly margaric acid and some sebacic acid, provided by the decomposition of the oleine,) small quantities of the odoriferous acids, (acetic, butyric, &c.,) and some acroleine. The acrid and irritant odor which this last substance gives out especially characterizes the decomposition of fatty bodies by heat. It is produced from the glycerine only. If, instead of raising the heat gradually, we submit the fats or oils directly to a red heat, as by passing them through a red-hot tube, they are decomposed completely, and are almost entirely transformed into gaseous carburet- ted hydrogens, the mixture of which serves for illuminating purposes, and yields a far bet- ter light than ordinary coal gas. In places where the seed and fish oils can be procured at a low price, these substances might be employed with great advantage for this purpose. Action of Alkalies on the Oih. — When the fats or oils are boiled with potash or soda, they are decomposed into glycerine and the fatty acids, with assimilation of water by both the gh'cerine and the fatty acids. Thus oleine yields glycerine and oleic acid, margarine, glycerine and margaric acid, and stearine, gljxerine and stearic acid. The glycerine dis- solves in the water and the fatty acids unite with the alkalies, forming soaps, (which see.) The action of ammonia on the oils is much less energetic ; it, however, .readily mixes with them, forming a milky emulsion, called volatile liniment, used as a rubefiicient in medicine. Upon mixing water with this, or by neutralizing the ammonia by an acid, or even by mere exposure to the air, the ammonia is removed and the oil again collects. By the prolonged action of ammonia, however, on the oils, true ammoniacal soaps are formed, and at the same time a peculiar body is formed, called by its discoverer (Boullay) marciaramid. It corre- sponds exactly with the ordinary amides, its composition is (C^^H'^XO^) = NH\C^''H^^O'^) or margarate of ammonia minus 2 equivalents of water. NH^0,C5'H='0' — 2H0 = NIP (C'^H^W) Margarate of ammonia. Margaramid. It is obtained by boiling the ammoniacal soap with water, when the margaramid swims on the top, and when allowed to cool solidifies. It is purified by solution in boiling alco- hol, which deposits it again on cooling in the crystalline state. It is a white, perfectly neu- tral solid, unalterable in the air, insoluble in w;iter, very soluble in alcohol and ether, espe- cially by the aid of heat. It fuses at about 140° Fahr., and burns with a smoky flame. It is decomposed when boiled with potash or soda, forming true soaps, with the liberation of ammonia, and also by acids of a certain degree of concentration. The alkaline earths and some metallic oxides unite with the fatty acids, forming insol- uble soaps, which in the case of lead is called a plaster. After glycerine and the fatty acids have once been separated, they do not readily again unite ; but Berthelot has succeeded in effecting this, by enclosing them lor a consideralile tim(; in a sealed tube, and subjecting them to a more or less elevated temperature, when the true oils are again producccl. Action of Acidi upon (he Oih.. — Sulphuric acid, (concentrated,) when added to tlie oils, unites with them energetically, the mixture becomes heated, ancl, unless cooled, chars with the liberation of sulphurous acid. When the mixture is cooled, the fats and oils un- dergo a similar change to that which the alkalies effect. There is formed some sulplio- glyceric acid, as well as combinations of margaric and oleic acids with sulphuric acid ; tlicso latter are again decomposed when mixed with water, liberating the fatty acids. Nitric arid (concentrated) attacks the fatty l)odies very rapidly, sitmetimes causing igni- tion. Dilute nitric acid acts less powerfully, forming the same compounds which wc obtain by acting on the several constituents of the oils separately. Iliiprinitric acid, or nitrous acid, converts the; oW'ine of the non-drying oils into a solid fat, elnidlne. Chlorine and bromine act on the fatty oils, produi'ing hydrochloric and hydrobromic acids, and some substitution compounds containing chlorine or bromine. When moist chlorine gas is passed into the oils, the tt'mi>erature rises, but it does not cause explosion. Bromine, on the contrary, acts with violence. The chlorine and l>romine pnxhicts thus obtaitied arc generally of a yellow color, without tiustc or smell. They are heavier than water, and possess a greater consistence than the pure oils. Exposed to tlie air when slightly heated, they become considerably harder. 816 OILS. Iodine also attacks the oils, forming substitution compounds. The fatty oils are divided into two classes, drying and non-drying oils, which are charac- terized by their dirterent deportments when exposed to the atmosphere. In close vessels, oils may be preserved unaltered for a very long time, but with contact of the atmosphere they undergo progressive changes. Certain oils thicken and eventually dry into a trans- parent, yellowish, flexible substance, which forms a skin upon the surface of the oil and retards its further alteration. Such oils are said to be drying, or siccative^ and are on this account used in the preparation of varnishes and painters' colors. Other oils do not dry up, though they become thick, less combustible, and assume an offensive smell. These are the non-dryiiig oils. In this state they are called rancid, and exhibit an acid reaction, and irri- tate the fauces when swallowed, in consequence of the presence of a peculiar acid, which may be removed in a great measure by boiling the oil along with water and a little common magnesia for a quarter of an hour, or till it has lost the property of reddening litmus. While oils undergo the above changes, they absorb a quantity of oxygen equal to several times their volume. Saussure found that a layer of nut oil, one quarter of an inch thick, enclosed along with oxygen gas over the surface of quicksilver in the shade, absorbed only three times its bulk of that gas in the course of eight mouths ; but wlien exposed to the sun in August, it absorbed GO volumes additional in the course of ten days. This absorp- tion of oxygen diminished progressively, and stopped altogether at the end of three months, when it had amounted to 115 times the bulk of the oil. Ko water was generated, but 21'9 volumes of carbonic acid were disengaged, while the oil was transformed in an anomalous manner into a gelatinous mass, which did not stain paper. To a like absorption we may ascribe the elevation of temperature which happens when wool or hemp, besmeared with olive or rapeseed oil, is left in a heap ; circumstances under which it has frequently taken fire, and caused the destruction of both cloth-mills and dockyards. In illustration of these accidents, if paper, linen, tow, wool, cotton mats, straw, wood shavings, moss, or soot, be imbued slightly with linseed or hempseed oil, especially when wrapped or piled in a heap, and placed in contact with the sun and air, they very soon spon- taneously become hot, emit smoke, and finally burst into flames. If linseed oil and ground manganese be triturated together, the soft lump so formed will speedily become firm, and ere long take fire. Although most of the fixed oils and fats are mixtures of two or more of the substances oleine, margarine and stearine, yet there appeai-s to be different modifications of these sub- stances in drying and non-drying oils ; for instance, it is only the oleine of the non-drying oils that solidifies when treated with nitrous acid or nitrate of mercury ; and again the dif- ference is shown in the fact of some oils drying completely, while others only thicken and become rancid. A patent was taken out in May, 1849, by Messrs. Bessemer & Heywood, for a machine to be used for expressing oils from seeds. Fig. 467 is a drawing of it. The bedplate of 46*7 framing, if!) is yellowish, rather thick, with the odor of colza oil, of a bitter and acrid taste. It is solid at 5' Fahr. It gives to hot water a bitter substance. It is but little soluble in alcohol, and the solution has an acid reaction. It contains margarine, and oleine, and some benzoic and acetic acids. Butter of nulmcfiR. — This is commonly known in the shops as ej-prcsxcd oil of mace, and is prepared by beating the nutmegs to a paste, placing them in a bag and exposing them to steam, and afterwards pressing between heated plates. It is imported in oblong cakes (covered by some leaves), which have the shape of common bricks, only smaller. It is of an orange color, firm consistence, fragrant odor, like that of nutmegs. Schroder found 16 parts of the oil, expressed by himself, contained 1 part of volatile oil, 6 parts of brownish yellow fat, and 9 parts of a white fat. The volatile oil and yellow fat are both soluVjle in cold alcohol and cold ether ; the white fat soluble in alcohol and ether, when boiling, but insoluble in them when cold. By saponification it yields glycerine and myristic acid (C^' H'^'0^,HO). A false article is sometimes made, composed of animal fat, boiled with powdered nutmegs, and flavored with sassafras (Plni/fair). The geijuine article may be known by being soluble in four times its weight of boiling alcohol, or half that quantity of boiling ether. Its principal use is in medicine. It must not be confounded with essential oil of mace. The Drying Oils. Linseed oil. — The oil is obtained by expression from the seeds of the common flax {Lininn usitatissimum), either with or without the aid of heat; the latter, being known as cold-drawn linseed oil, is better than that expressed by heat. By cold expression the seeds yield about 20 per cent, of oil, but by the aid of heat from 22 to 27 per cent. The cold- drawn oil is of a light yellow color, while that obtained by heat is brownish, and easily becomes rancid. It has a peculiar smell and taste. According to Saussure its sp. gr. is 0-9395 at 53-6° Fahr.; 0-9125 at 122' Fahr. ; and 0-8815 at 201" Fahr. At 4' Fahr, it becomes paler without solidifying; but at —17-5' Fahr. it forms a solid mass. It is soluble in 5 parts of boiling alcohol, in 40 parts of cold alcohol, and in 1-6 parts of ether. It consists principally of a liquid oil, which differs, however, as before mentioned, from the oleine of olive oil and the non-drying oils in general, and is called linoleine, and yields by saponification, linoleic acid. It also contains some margarine, and generally some vegetable albumen and mucilage. Pure linseed oil has the following composition: — Sacc. Lefort Caroon Hydrogen - Oxygen 78-05 10-83 11.12 78-18 11-09 10-73 7519 - 10-85 13-96 75.14 1112 - 13-74 100-00 100-00 100-00 100-00 Linseed oil is easily saponified, yielding a mixture of oleate and margarate of the alkali, and a large quantity of glycerine. It is acted on rapidly by nitric acid, producing margaric acid, pimelie acid, and some oxalic acid. Chlorine and bromine act on it, yielding thick colored products. When linseed oil is heated in a retort, it gives off, before entering into ebullition, large quantities of white vapors, which condense to a limpid colorless oil, possessing the odor of new bread. As OILS. 825 soon as the ebullition commences these vapors cease ; the oil froths up, and at length there Is left a thick n;('l:itiiious residue, very much resembling caoutchouc. Tiie principal use of linseed oil is in making paints and varnishes. It attracts oxygen rapidly from the air and solidifies, and this property is what renders it so valuable for these purposes : it is the most useful of all the drying oils. The small quantities of vegetable albumen and mucilage which the oil naturally contains, appear, according to Licbig, to impair, to a certain extent, its drying properties, and the real object which is obtained by boiling these oils with litharge, or acetate of lead and litharge, is the removal of these sub- stances ; the oil then being brought more directly in contact with the oxygen of the atmos- phere, dries up more rapidly. It was previously thought that some of the litharge was reduced to metallic lead, oxidizing at the same time some of the linoleine ; but Liebig's opinion seems to be more likely to be correct. The boiling of the oil requires some little care. A few hundredths of litharge is added to the oil, or some use acetate of lead and litharge, and, as before stated, about an eighth part of resin ; this is boiled with the oil, the scum removed as it forms, and when the oil has acquired a reddish color, the source of heat is removed, and the oil allowed to clarify by repose. Liebig thinks heat is not necessary, and his process for treating the drying oils, in order to increase their siccative properties, has already been mentioned. According to MM. E. Barruel et Jean, the resinification of the drying oils may be effected by the smallest quantities of certain substances, which would act in the manner of ferments. The borate of manganese acts in this way ; a thou- sandth part of this salt being sufficient to determine the rapid desiccation of these oils. Linseed oil is used in the manufacture of printers' ink ; being heated in a vessel until it takes fire, it is allowed to burn some time, then it is tightly covered ; and subsequently mixed with about one-sixth of its weight of lamp-black. The thin gummed silks receive the last of their many layers with boiled linseed oil ; it is also used for leather varnishes, and for oil-ck)ths. The residue, after the expression of the oil from the seeds, is called oil-cake, and is sold for feeding cattle ; that obtained from the English linseed is the best. Walnut oil. — This is obtained by expression from the ordinary walnuts deprived previously of their skin, which are the produce of a tree {Jaglans regia) which is a native of Persia, but cultivated in this country for the sake of the nuts. When recently prepared it is of a greenish color, but by age becomes a pale j'cllow. According to M. Saussure its sp. gr. at 53-6^ Fahr. is 0-9283, and at 201" Fahr., 0-871. It has no odor and an agreeable taste. At 6° Fahr. it thickens, and at 17"5^ Fahr. it forms a whitish mass. The nuts yield about 50 per cent, of oil. It dries still more rapidly even than the linseed oil. It is principally used for paints and varnishes, and from its lighter color, it is often used for white paints. Oil of the Hazd-md. — This is extracted from the seeds of the Corylus avellana, which yield about 60 per cent, of the oil. It is liquid, has only a slight color, no odor, and a mild taste. Its sp. gr. at 59'' Fahr. is 0-9242. At 14° Fahr. it solidifies. Poppy (Yd. — This is expressed from the seeds of the common poppy, (Papaver soni- 7iiferum,) wliich grows wild in some parts of England. It is cultivated in very large quan- tities in Hindostan, Persia, Asia Minor, and Egypt, for the sake of the opium which is ob- tained from the capsules. It is cultivated in Europe for the capsules, which are used in medicine, or for the oil extracted from the seeds. The oil is obtained, by expression, from the seeds, which do not possess any of the narcotic properties of the capsules. These seeds are sold for birds, under the name of jnaw-seed. This oil resembles olive oil in its appearance and taste, and is often used to adulterate it. Its sp. gr. at 59' Fahr. is 9249. It becomes solid at 0^ Fahr. It is soluble in 25 parts of cold alcohol, and in 6 parts of boiling alcohol, and may be mixed in all proportions with ether. It is used sometimes for lighting, and after treatment with Jitharge or subacetate of lead is used for paints. Hempxeed Oil. — The seeds of the common hemp (Cannabis .tafira) yield, by expres- sion, from 14 to 25 per cent, of their weight of a fixed oil. It is obtained principally from Russia, but the native places of the plant are Persia, Caucasus, and hills in the north of India. The seeds are small ash-colored shining bodies. Tiiey are demulcent and ol(>aginous, but possessing none of the narcotic properties of the plant. They arc employed for feed- ing cage-birds, and it has been stated that the plumage of certain birds, as the bulHinch and goldfinch, becomes changed to black by the prolonged use of this seed. Wiien fresh, this oil is greenish, but becomes yellow by age. It has a laced on a piece of wliite gl.iss, resting on a sheet of wiiite paper ; different colorations appear, which they state are characteristic of the difl'erent oils ; thus olive oil gives a deep yellow tint, becoming greenish by degrees; colza oil a greenish blue ; I'oppv oil, a pale yellow tint, with a diily gray outline ; hempseed oil, a very deej) emerald tint; and linseed oil liecomes brownisli red, passing directly into blackish brown, -- The principal use of this ta1)le is to distinguish fish from animal and vegetable oils, owing to the distinct red color which the former assume, and which is so distinct that one per cent, of fish oil can be detected in any of the others. Hempseed oil also becomes brown-yellow, and so thick that the vessel containing it may be inverted, for an instant, without losing any of its contents, whilst linseed oil acquires a much brighter yellow color, and remains fluid. India-nut oil is characterized by giving a white mass, becoming solid in five minutes after the addition of the alkali, which is also the case with Gallipoli and pale rape oils, while the others remain fluid. The next test he uses is dilute sulphuric acid, and as the reactions vary with the strength of the acid, he employs three different strengths. Sulphuric Acid of sp. gr. 1-475. The mode of applying this acid consists in agitating one volume with five volumes of oil until complete admixture, and after standing fifteen minutes the appearance is takon as the test reaction. Not Colored. Colored. Animal. Vegetable. Fish. Animal. 1 Vegetable. Lard, dirty. India-nut. Pale rape- seed. Poppy. Castor. Sperm ) light Seal C red. Cod- [ pur- liver ) pie. Neat's- ) yellow •^oot f tinge. 0]i.ve - -1 G^Upoli -f f"'^"^ Sesame - [ *'"S^- Linseed - green. Hc,„psced .] '»«- French nut - brownish. The most striking reactions in this table are those presented by hempseed and linseed oils, for the green coloration which they acquire is such, that if they were used to adulte- rate any of the other oil.-<, they would be immediately detected if only present to the amount of ten per cent. The red color assumed by the fish oils with this test is also sufficiently marked to enable us to detect them in the proportion of one part in 100 of any other oil, and it is at the point of contact of oil and acid, when allowed to separate by standing, that the red color is prin- cipally to be noticed. OILS. 833 Sulphuric acid, sp. gr. 1530. One volume of this acid is mixed, as before, with five volumes of oil and allowed to stand five minutes. Light Colorations. Marked Colorations. Animal. Vegetable. Fish. Vegetable. f""' \ wLi.e. Olive Sesame India-nut Poppy - Castor - Pale rapeseed greenish white. greenish dirty white. ■ dirty white. pink. Gallipoli • 1 intense French nut ) gray. ( intense Hempseed \ green, Linseed - 1 dirty ( green. As hempseed, linseed, fish, Gallipoli, and French nut oils are the only ones that assume with the above reagent a decided coloration, they can be discovered in any of the others. Sulphuric acid of sp. gr. 1"635. This acid is used in a similar manner to those above, and the coloration noted after two minutes. Not Colored. Distinctly Colored. Vegetable. Fish. Animal. Vegetable. Poppy. Sesame. Castor. Sperm \ Seal - f intense Cod- r brown, liver ; Olive (light) - - \ Hempseed (intense) - > green. Linseed - - - ) Gallipoli - - - \ Pale rapeseed - - f . French nut - - f ^^"^"• India-nut (light) - ) The colorations produced by sulphuric acid, sp. gr. 1-635, are so marked, that they may be consulted with great advantage in many cases of adulteration : for example, Mr. Calvert has been enabled to detect distinctly ten per cent, of rape-seed in olive oil, of lard oil in poppy oil, of French nut oil in olive oil, of fish oil in neat's-foot oil. This appears to be the maximum strength that can be used, for nearly all the oils begin to carbonize, and their distinct coloration to be destroyed. Action of nitric acid, of different strengths, on oils : — Nitric acid of sp. gr. 1'180. One part of this acid, by measure, is agitated with five parts of oil, and the appearance, after standing five minutes, is described in this table. Not Colored. Colored. Fish. Animal. Vegetable. Fish. Animal. Vegetable. Cod- liver. Lard. India-nut. Pale rape- seed. Poppy. Castor. Seal - pink. Neat's- ('^;.^ Olive - - ) . , Gallipoli .[greenish. Hempseed -i ^''^^ ^ 1 green, j French nut - ) 1 Sesame f „ 1 /^...,„„«\ r vcllow. I (orange) - ( - Linseed - ; This test is sufficiently delicate to detect distinctly 10 per cent, of hempseed oil in lin- seed oil, as the mixture assumes the greenish hue so characteristic of the former. Althoujjh olive acquires a greenish color, still its shade is such that it is entirely distinguished from that of hempseed. Nitric acid of xp. gr. r220. The proportion of acid used, and the time of contact are the same as the last. . Vol. in.— 53 834 OILS. Not Colored. Colored. Fish. Animal. Vegetable. Fish. Animal. Vegetable. Cod- liver. Lard. India-nut. Pale rape- seed, j XT .1 ( light Neat s- ) " , '- 1 c. Poppy (yel- ) low) - . 1 . 17 u . r red. iTcncn nut - ( Ses;ime - ) Olive - - ) . , GaUipoli - \ g-"^^"'^^- i greenish Henipseed - -j dirty ( brown. Linseed - yellow. The chief characters in the above table are those presented by hempseed, sesame, French nut, poppy, and seal oils, and they are such that they' not only may be employed to distin- guish them from each other, but are sufficiently delicate to detect their presence when mixed with other oils, in the proportion of 10 per cent. Nitric acid of sp. fjr. 1'330. One part of this acid is mixed with 5 parts of oil by measure, and remains in contact 5 minutes. Not Colored. Colored. Vegetable. 1 Fish. Animal. Vegetable. 1 India nut. ; Pale rape- seed. Castor. Sperm ^ Seal - f , Cod- r'^- liver. ) Neat's- \ light foot f brown. i very Lard •< slight ( yellow. Poppy French nut (dark) Sesame (dark) OHve - - Gallipoli Hempseed - Linseed red. greenish. greenish dirty brown, green, becom- ing brown. The colorations here described are very marked, and can be employed with advantage to discover several well-known cases of adulteration : for instance, if 10 per cent, of sesame or French nut oil exists in olive oil ; but the same proportion of poppy oil cannot be thus detected, as the color produced is not so intense as in the other cases. But if any doubt remained in the mind of the operator, as to whether the adultering oil was sesame, French nut, or poppy, he would be able to decide it by applying the test described in the next table, where he will find that French nut oil gives a fibrous semi-saponified mass, sesame a fluid one, with a red liquor beneath, and pippy, also a fluid mass, but floating on a colorless liquid. The successive application of nitric acid of sp. gr. 1'330, and of caustic soda of sp. gr. 1'340, can be also successfully applied to detect the following very frequent cases of adul- teration ; first, that of Gallipoli with fi.sh oils, as Gallipoli oil assumes no distinct color with the acid, and gives with a soda a mass of a fibrous consistency, whilst fish oils are colored red, and becomes mucilaginous with the alkali. Secondly, that of castor oil with poppy oil, as the former acquires a reddish tinge, and the mass with the alkali loses much of its fibrous appearance. Thirdly, rapeseed oil with French nut oil, as nitric acid imparts to the former a more or less intense red tinge, which an addition of the alkali increases, and renders the semi-sapon- ified mass more fibrous. Mr. Calvert here remarks that the coloration which divers oils assumes under the influ- ence of the three test nitric and sulphuric acids, clearly show that the reason why chemists had not previously arrived at satisfactory results in distinguishing oils in their various adul- terations, was that the acids they employed were so concentrated that all the distinctive colorations were lost ; the oils became yellow or orange ; but there is no doubt that the above reagent will enhance the value of Mr. F. Baudet's, as they afibrd very useful data to specify the special oils mixed with olive oil. Caustic noda of up. gr. 1"344. The following reactions were obtained on adding 10 volumes of this test liquor to the 5 volumes of oil which had just been acted upon by 1 part of nitric acid: — OILS. 835 A flbroua mass is formed. A fluid mass is formed. | .\nimaL Vegetable. Fish. Animal. Vegetable. foot } '^^'^^- Gallipoli ) India-nut V white. Castor • ) French ( ^, nut -r^^- Hemp- [ light seed - ) brown. Sperm. Seal. Cod- liver. Lard. S";«- • - -[white. Pale rapeseed - - ) Linseed - - '\£,^,^ Poppy (light) - - red. ( brown ) Sesame - ■< Uquor V amber. ( beneath ) Having given in a previous paragraph some of the most useful reactions noted in this table, attention will simply be called to the following mixtures : neat's-foot with rape, Gallipoli with poppy, castor with poppy, hempseed with linseed, sperm with French nut, and Gallipoli with French nut. It is necessary also here to mention that the brown liquor on which the semi-saponified mass of sesame oil swims, is a very delicate and characteristic reaction. The next test used is phosphoric acid. One part by measure of syrupy trihydrated phos- phoric acid is agitated with 5 parts of oil. The only reaction to be noticed is the dark red color, rapidly becoming black, which phosphoric acid imparts exclusively to the fish oils, as it enables us to detect 1 part of these oils in 1,000 parts of any other animal or vegetable oils, and even at this degree of dilution, a distinct coloration is communicated to the mixture. Mixture of sulphuric and nitric acid. This test is formed of equal volumes of sulphuric acid of sp. gr. 1'845, and nitric acid of sp. gr. 1-330, and is thus used : one volume of this mixture is mixed with 5 volumes of oil, and allowed to stand 2 minutes. By this test 3 of the oils remain nearly colorless, viz., those of poppy, olive, and India-nut, while all the others become brown, except sesame, hempseed, and linseed, which become green, turning after, sesame, intense red, and hemp- seed and linseed, black. . „„^ „^ .„ ' A.qua regia. This test is composed of 25 volumes of hydrochloride acid of sp. gr. 1-155, and 1 volume of nitric acid of sp. gr. 1-330, and allowed to stand about 5 hours; the reactions in the following table are those which take place when a mixture of 5 volumes of oil and 1 of the aqua regia ie agitated and allowed to stand 5 minutes. Not Colored. Colored. Animal. Lard. Vegetable. ' Fish. Animal. Vegetable. Olive. 1 Sperm (slight) I Neat's- < slight foot ( yellow. French nut ^ Gallipoli. ! Seal (slight) - • yellow Sesame - { ,.„,,„^ Linseed . h^How. India-nut. ! Cod-liver Pale rape- • (greenish) ) seed. , Hempseed - greenish. Poppy. Castor. When the facts contained in this table are compared with the preceding ones, we are struck with their uniformity, and are led to infer that no marked action had taken place ; but this conclusion is erroneous, as most of them assume a vivid and distinct coloration on the addition of solution of soda of sp. gr. 1-340, as seen in the following table : — A fibrous mass is formed. 1 A fluid mass is formed. Animal. Vegetable. • Fish. .\nimal. Lard, Vegetable. Neat's- ) brownish foot \ yellow. Gallipoli ] 1 Sperm '\ Olive - white. (yellowish) India-nut y white. 1 Seal { orange- Cod- t yellow. pink. Poppy intense rose. Pale rape- liver ' orange seed (yel- (lowish) Sesame - with brown Castor pale rose. liquor beneath. French nut - orange. Linseed - orange. .Ho-P-dj,'*. 83( 2 c e fe; to s } OILS. o o K a < Fold white mass. Fil)rous yellowish- white nias.s. Fibrous white ma.ss. Fibrous yellowish- white ma«s. Fluid intense ro.se- colored mass. Fluid orange mass with brown liquor -^ • ■fz 2 ?2 l^-'E-^-T-ll !||«ii|i||t mas.s. Fluid orange- yellow n C = PP • • . . P . Greei'. Greenish- yellow. Slight yellow. P 2, ^ Orange- yellow. Dark brown. Orange- white. Dark brown. Slight yellow. 1^" p£ tI-3 C.S2 2i5S .3 '5-3 Green beecuniug black. Ditto Brown. Dark brown. c c pp a d — .* 5 -• i; « O + i i ^ - =S . . B3>. • • Green. Brown yellow- green. ■3 3 P c pp Fluid white mass. Fibrous ditto. Ditto Fluid ditto Light red fluid uuiss. if Fluid red muss, with brown liquor .a 5 III Fibrous light brown mass. Fluid yellow mass. Fluid mass. Fibrous white luass. 1 "3 fa = 1 S i a o ■3 1 P • Greenish dirty brown. Green becoming brown. Very slight yellow. Light brown. •3 c pp < - .2 o 1 P O Orange- yellow. P • Grepnish dirty brown. Yellow. Light yellow. P ■3 1. < -• !2 o 1 i • • • >• • Dirty greeii. Yellow. Light yellow. ^1 it ^ rH "■ ■!■<£' •/I Light brown. Brown. d 3 • • Intense green. Green. Light brown. Browu. ^ £ PP a. (A Greeiiisli- white. Gray. Dirty white. rink. Dirty while. 33 a. ^ •3 -3 Intense green. Dirty green. Dirty Wllili!. Brownish (liny white. •6 p| to ~ < -2 to ? -J o JI2 ■ • J3 c 2 a 11- a- • Intense green. Green. Dirty white. Yellow tingo. 1 to P;? a. _ - s o Thick and white. Dirty yellowish- white. Ditto 5 3 P i Thick brownish- yellow. Fluid yellow. Pinki.sh- wliite. Dirty yellowish- white. •3 g CS P "55 pp I Olivo Gallipoli- •- India-nut Pale rapesecd • Poppy - - - 3 s c b. CS Ilempseed Linseed - Lard ... Noat's-foot s c. m 1- Is OPEKAMETEE. The effects described in tliis table are such that we can discover with facility 10 per cent, of a given oil in many cases of adulteration ; lor example, poppy in rape, olive in (.JaUipoli and India-nut, as nil of them assume a pale rose color; but wnen poppy is mixed with olive or castor oils, there is a decrease in the consistency of the semi-saponitied matter. By the aid of the above rea;;ents we can also ascertain the presence of U> per cent, of French nut in olive or linseed oils, as the semi-.saponified ma.ss becomes the more fluid, and the presence of French nut in pale ra|)e, (.iallipoli, or India-nut oils, is recognized in con- se(|Uence of their white mass accjuiring an orange hue ; lin.seed oil is delected in hempst'cd oil, as it renders the fibrous mass ot llie latter more mucilaginous. Sesame oil also gives with this reagent the .same reaction as with nitric acid and alkali, and poppv oil is distinguished from all other oils, by giving, in thi.s case, a semi-sapouiiied mass ol a bcautilul rose color. To give an idea how the above tables are to be used, Mr. Calvert suppo.^es a sample of rapeseed oil adulteiated witii one very difficult to discover. He first applies the caustic alkali tost, which, on giving a white mas.s, proves the alisence of the fish oils, together with those of hempseed or linseed ; and as no distinct reaction is produced by the sami)le of oil under examination with the 3 sulphuric and nitric acids above mentioned, poppy and sesame oils aie tlirown out as they are reddened, neatV-foot oil, India-nut, castor, olive, and l.ird oils resting only in the .scale of probability. In order to discover which of these is mixed with the suspected oil, a ])ortion of it is agitated first with nitric acid of .sp. gr. r3(K», and then with c.iustic .soda, and their mutual action excludes neat's-foot, India-nut, and ca.stor oils, as the sample does not give a fluid semi-saponified mass. The absence of olive oil is proved by no green coloration being obtained on the application of syrupy phosphoric acid. As to the presence of lard oil, it is ascertained on c.iustic soda being added to the oil which has been previously acted on by aqua legia, as the latter gives a fibrous yellowish semi-saponi- fied mass, whilst the former yields a pink fluid one. In order to facilitate the detection of any adulteiation, Mr. Calvert, gives a general table of the preceding reaction.s. (See table on preceding page.) — H. K. B. OI'AL maybe regarded as an uncleavable quartz. Its fracture, eonchoidal ; lustre, vitreous or resinous ; colors, white, yellow, red, brown, green, gray. Lively play of light ; hardness, 5'5 to Co; specific gravity, 2 091. It occurs in small kidney-shaped and stalactitic shapes, and huge tuberose concretions. The phenomena of the play of colors in precious op.d have not been .satisfactorily explained. It seems to be connected with the regular structure of the mineral, llauy attributes the play of colors to the fissures of the interior being filled with films of air agreeably with the law of Newton's colored rings. Moh^, however, thinks this would produce iridescence merely. Brewster concludes that it is o.ving to fi.ssures and cracks in the interior of the mass of a uniform shape. It is said that the opal wliich grows after a while dull and opaque may be restored to its former beauty if put for a short time in water or oil.(?) The precious opal stands high in estimation, and is considered one of the most valuable gems, the size and beauty of the stone and the variety of the colors determining its value. The so-called "mountain of light," an Hungarian opal in the Great Exhibition of 1851, weighed 52,U carats, and was estimated at £4,000 sterling. In Vienna is a precious opal weighing 17 oz. ; and it is said a jeweller of Amsterdam olfered iialf a million of florins for it, which was refused. Hydrophane, or oculis mundi, is a variety of opal without transparency, but acquiring it wjjen immersed in water, or in any transparent fluid. Precious opal was found by Kla[)rotli to consist of silica, 90; water, 10; which is a very curious combination. Hungary has long been the only locality of precious opal, where it occurs near Caschau, along with common and semi-opal, in a kind of i)orphyry. Fine varieties have, however, been lately discovered in the Faroe islands; and most beatiful ones, .sometimes quite transparent, near (iracios h Dios, in the province of Honduras, Ameiica. The red and yellow bright colored varieties of (ire-opal are found near Zimapan, in Mexico. Precious opal, when fasiiioiied lor a gem, is generally cut with a convex surface; and if large, pure, and exhii)itiiig a hiight play of colors, is of considerable value. In modern times, flue opals of moderate bulk have lieen fre(iuently sold at the price of diamonds of equal size; the Tuiks being particularly fond of them. The estimation in which opal was held by the ancients is hardly credible. Nonius, the Roman senator, preferred banisiunent to parting with his favorite opal, which was coveted by Miirk Antony Opal which appears quite red when held against the light, is called giraaol by the French ; a name al.so given to the sapphire or corundum asteria or star-stone. OPERAMETER is the name givi'n to an apparatus invented by Samuel AValkcr, of Leeds. Itconsistnof a train ot toothed wheels and ])inionscnclo.sed in a box, having indexes attached to the central arbor, like the hands of a clock, and a dial plate; wT^ercljV the num- ber of rotations of a shaft projecting iiom the posterior j)art of the i)ox is shown. If this shaft be connected Ijy any convenient means to the working parts of a gig, mill, shearing frame, or any other machinery of that kind for dressing cloths, the number of rotations made OPIUM. by the operating macbine will be exhibited by the indexes upon the dial plate of this apparatus. A similar clock-work mechanism, called a couyiter, has been for a great many years employed in the cotton factories and in the pumping engines of the Cornish and other mines, to indicate the number of revolutions of the main shaft of the mill or of the strokes of the piston. A common pendulum or spring-clock is commonly set up alongside of the counter; and sometimes the indexes of both are regulated to go together. OPIUM is the juice which exudes from incisions made in the heads of ripe poppies, (Papaver Komni/rnDii,) Tcndi^'red concrete by exposure to the air. The best opium which is found in the European markets comes from Asia Minor and Egypt ; what is imported from India is reckoned inferior in quality. This is the most valuable of all the vegetable products of the gum-resin family, and very remarkable for the complexity of its chemical composition. ORCHELLE WEEDS. The cylindrical and flat species of Roccella used in the manu- facture of Orchil and Cudbear, are so cdled by the makers. Dr. Pereira says Mr. Harman Visger, of Bristol, " informs me that every lichen but the best orchella weed is gone, or rapidly going out of use, not from deterioration of their quality, for, being allowed to grow, they are finer than ever ; but because the Angola weed is so superior in quality, and so low priced and abundant, that the product of a very few other lichens would pay the expense of manufacture." In the Ffii/osopliical Transactions for 1848, Dr. Stenhouse has a valuable paper on the coloring matters of the lichens. From it we extract his directions for estimating the coloring matter in lichens by means of a solution of hypochlorite of lime. Any convenient quantity of the orchelle weed may be cut into very small pieces, and then macerated with milk of lime, till the coloring matter is extracted. Three or four macerations are quite sufficient for this purpose, if the lichen has been sufficiently com- minuted. The clear liquors should be filtered and mixed together. A solution of bleach- ing powder of known strength should then be poured into the lime solution from a graduated alkalimeter. The moment the bleaching liquor comes in contact with the lime solution of the lichen, a blood-red color is produced, which disappears in a minute or two, and the liquid has only a deep yellow color. A new quantity of the bleaching licjuid should then be poured into the lime solution, and the mixture carefully stirred. This operation should be repeated so long as the addition of the hypochlorite of lime causes the production of the red color, for this shows that the lime solution still contains unoxidizcd colorific principle. Towards the end of the process, the bleaching solution should be added by only a few drops at a time, the mixtuie being carefully stirred between each addition. We have only to note how many measures of the bleaching liquid have been required to destroy the coloring matter in the solution, to determine the amount of the colorific principle it contain- ed. Dr. Stenhouse suggests the following method for extracting the colorific principle for transport: — Cut the lichens into small pieces, macerate them in wooden vats with milk of lime, and saturate the solution with either muriatic or acetic acid. The gelatinous principle is then to be collected on cloths and dried by a gentle heat. In this way the whole of the heat can be easily extracted, and the dried extract transported from the most distant localities. ORES, DRESSING OF. In metalliferous veins the deposits of ore are extremely ir- rc'iular and much intermixed with gangue or vein stone. In excavating the lode, it is usual for the miner to effect a partial separation of the valuable from the worthless porticfti ; the former he tempoiarily stows away in some open place imdcrground, whilst the latter is cither employed to fill up useless excavations, or in due course sent to surface to be lodged on the waste heaps. From time to time tlie valuable part of the lode is drawn to the top of the shaft, and from thence conveyed to the dressing floors, where it has to be prepared for metallurgic treatment. This process is known as dressing, and in the majority of instances includes a series of operations. In this country it is chiefly restricted to mechanical treatment, the chemical manipulation being performed by the .smelter. Hand labor, picking, washing, sizing, and reducing machinery, together witii water-concentrating apparatus, comprise the usual re- sources of the dresser, but sometimes he may find it useful to have recourse to the furnace, since it may happen that by slightly changing the chemical state of the substances that compose the ore, the earthy jiarts may become more easily separable, as also the other foreign matters. Willi this view, the ores of tin are often calcined, which, by separating the arsenic and oxidizing the iron and copper, furnishes the means of obtaining, by the subsequent washing, an oxide of tin much purer than could be otherwise procured. In general, however, these are rare cases ; so that the washing almost afways immediately succeeds the f)icking, crushing, or stamping processes. Before entering u|)on the description of machinery employed in the concentration of ores, it i.-< impartant to notice the principles upon which the various mechanical operations are based. ORES, DKESSING OF. 839 If bodies of various sizes, forms, and densities be allowed to fall into a liquid, in a state of rest, the amount of resistance wliich lliey experience will be very unequal, and conse- quently they will not arrive at the bottom at tlie same time. This necessarily produces a sort of classification of the fraj^mcnts, which becomes apparent on examining the order in which they have been deposited. If it be supposed that the substances have similar foDus and dimensions, and d'^er from each other in deusili/ only, and it is known that the resistance which a body will experience in moving through a liquid medium depends solely on its form and extent of surfaces, and not on its specific gravity, it follows that all substances will lose under similar circumstances an equal amount of moving force. Tills loss is proportionally greater on light bodies than in those having more consider- able density. The former for this reason fall through the liciuid with less rapidity than the denser fragments, and must therefore arrive later at the bottom, so that the deposit will be constituted of diH'ercnt strata, arranged in direct relation to their various densities, the heaviest being at the bottom, and the lightest at the top of the series. Supposing, on the contrary, that all the bodies which fall through the water possess similar forms and equal specific gravities, and that they only differ from each other in point of volume, it is evident that the rapidity of motion will be in proportion to their sizes, and the larger fragments will be deposited at the bottom of the vessel. As the bodies on starting are supposed to have the same forms and densities, it follows that the resistance they experience whilst descending through water will be in 'proportion to the surface exposed, and as the volumes of bodies very according to the cubes of their corresponding dimensions, whilst the surfaces only vary in accordance with the squares of the same measurements, it will be seen that the force of movement animating them is regulated hi/ their cubes whilst their resistance is in proportion to their squares. If, lastly, it be imagined that all the fragments have the same volume and density but are of various forms, it follows that those possessing the largest amount of surface will arrive at tlie bottom last, and consequently the upper part of the deposit will consist of the thinnest pieces. It is evidently then of the greatest importance that the grains of ore which are to I)e concentrated by washing should be as nearly as possible of the same size, or otherwise the smaller surface of one fragment, in proportion to its weight, will in a measure compensate for the greater density of another, and thus cause it to assume a position in the series to which by its constitution it is not entitled. This difficulty is constantly found to occur in practice, and, in order as much as possiVjle to obviate it, care is taken to separate by the u.se of sieves and trommels into distinct parcels, the fragments which have respectively nearly the same size. Although by this means the grains of ore may to a certain extent be classified according to their regular dimensions, it is impossible by any mechanical contrivance to regulate their forms, which must greatly depend on the natural cleavages of the substances operated on, and hence this circumstance must always in some degree affect the results obtained. Each of the broken fragments of ore must necessarily belong to one of the three follow- ing classes: — the ^rv< class consists of those which are composed of the mineral sought without admixture of earthy matter. The second will comprehend the fragments which are made up of a mixture of mineral ore and earthy substances, whilst the //nrJ division may be wholly composed of earthy gangue without the presence of metallic ore. By a success- ful washing these three classes should be sejjarated from each other. The most difficult and expensive vein stuff for the dressing floors is that in which the constituents have nearly an uniform aggregation, and where the specific gravity of the several substances approximate closely to c6,ch other. In such case the ore is only sep- arated from the waste after much care and labor, and often at the loss of a considerable portion of the ore itself When, however, the ore is massive and distinct from the gangue, and the specific gravity of the latter much less than the former, then the operation of clean- ing is usually very simple, effected cheaply, and with but little loss on the ore originally present. The losses which may be sustained in the manipulation and enrichment of ores is a matter of great importance, and demands not oidy direct attention from the chief agent, but also calls for the constant vigilance of the dresser. No one can approve of a system which omits to record the initial (piantity of ore brought to the surface, noting only the tonnage and percentage of the parcel jiroduced for sampling. Yet such inattention jirevails generally in the mining districts of this country. What would be thought of a smelter who might systematically purchase and receive ores without ascertaining their produce, and reduce them in furnaces totally unfitted (or the purpose, without regarding the losses which might be sustained ? If he became insolvent it would excite no surprise, l»ut, on the contrary, the public would most likely loolv upon his position as the inevitable lesult of a defective and reprehensible mode of working. It will be admitted that mineral exploitatioiid are of a highly hazardous nature, and 840 ORES, DRESSING OF. Assayed 1770 that the risk of profit ought not to be increased either by ignorance or capclossness. "When ores are discovered, usually after the expenditure of much money, a certain amount of productive and dead cost is incurred before they can be rendered at the dressing floors; if then the least waste takes place there is not only a loss per ne, but the mine expenditure is augmented upon the lessened quantity, hence in no department of mining economics is it more essential to secure higher practical talent than in the dressing and management of vein stuff. The individual entrusted with this duty should be competent to assay the ores, have a knowledge of the losses resulting from their metallurgic treatment, and know ajiproximately the cost of enriching them on the floors as well as of smelting them ; he will then conduct his operations so that the cost and loss iu dressing will be less than the cost and loss in smelting. Some of the more friable ores, when simply exposed to the influence of water, exhibit a large mechanical loss, so much so, that it is considered oftentimes more profitable to put them to pile without attempting their enrichment. Now it may be laid down as an axiom that water will always steal ore, and the longer it is exposed to its influence, and the more complicated the manipulation, the greater will be the loss incurred. In addition, the constitution of certain ores is .so peculiar and delicate, that any attempt to concentrate tl;em beyond a given standard, by varying the treatment, is seen to lead to an enormous loss, as will be apparent by inspecting the following memoranda of practical results: — (A.)—The ore operated upon was sulphide of lead, associated with finely disseminated iron pyrites, oxide of iron, quartz, and a small portion of clay slate. In each case the vein stuff assayed 17 per cent, of metal. Quantity Quantity by weiglit. by wtight 1 washed and concentrated to "io ^ T fil per cent. 1 " " -40 S9 1 burnt, roasted, and do. '20 The loss on metal 57 " 2'4 washed aud do. "43 originally present 37^ " ■{ 1-56 y in the ore by vary •■ 20 loss by roasting ing the mechani- — 1-36 washed and concentrated to '40 cal treatment was 50 " ■8 roasted, washed, do. -42 33 " ■8 " " -69 J [ 16| " (B.) — Took two parcels of argentiferous lead ore, associated with carbonate of iron, a little quartz, and blende. Weight 'ii'-^u tons, which assayed 42i percent, for lead, and 29 oz. of silver per ton of metal. Crushed and carefully elaborated the same through jig- ging and buddle apparatus, obtained 14 '%o tons of ore, giving 54^ per cent, for lead, and 22 ounces of silver per ton of metal. The produce for lead was therefore raised 12 units at a loss of 49 per cent, of the initial quantity of metal and 95 ounces of silver. The com- mercial loss attending this operation, after making the several charges and allowances incident to the metallurgic reduction, was £91 14s., or equal to £2 14s. per ton on the original weight. Additional instances of heavy losses incurred in the concentrating process could be adduced if space permitted ; but it may not be unwise to direct special attention to the great waste often connected with the manipulation of both tin and argentiferous ores. In the former it occurs chiefly from the o.\ide of tin being much diffused through hard vein stone, requiring seveic mechanical treatment in order to liberate it, whilst in the latter the silver (not unfrcquently combined mechanically), imperceptible to the eye, floating away when subjected to water, and so subtle as to evade the most delicately devised apparatus. Tlie loss accruing in one large undertaking from this source alone upon 1,100 tons of ore was 3,026 ounces of silver worth £830, or equal to the interest on £16,600, at the rate of 5 per cent per annum. In order to determine the loss of metal which may arise in enriching ores, accurate assays and notations should be made of the quantity of vein stuff lodged on the floors, which should be compared with the metallic contents rendered merchantable, and the difl'erences estimated. It is not possible to ascertain the value of an improvement which would secure an additional one per cent, from the quantity of orey stuff annually sent to surface from the several mines in the United Kingdom ; but if it be reckoned only upon the sale value it would be scarcely less than £40,000 per annum. In determining the site for a dressing floor, and in making the mechanical arrangements, various points suggest themselves ; since, if they were overlooked, much loss would ensue to the undertaking, or otherwise it is evident that they could only be corrected by involving the proprietary in an increased outlay as well as a greater current expenditure. The first consideration should be to secure an ample supjily of water, with a good fall, and an ex- tensive area of ground. With advantages of this nature the machinery will be worked cheaply, the stud' gravitate through the various processes without returning to create double OHES, DKES6ING OK 841 carriage expenses, whilst the castaways may be sent to the waste heaps at a minimum cost. Tlie second point to be settled, is the class of machinery to be employed. This must ob- viously be based upon the character which the ores may present. If massive, and associated with light waste, simple apparatus will suffice ; but if the ore be sparsely diffused among heavy vein stone, it is probable that the various apparatus will have to be constructed with great nicety, varied in their principles of action, and that much precaution will have to be observed in order to create as little slime as possible, as well as to secure the initial ([uantity of ore against undue loss. In the disposition of the machinery there is also consider- able scope for practical intelligence ; it is not enough to wash, crush, jig, and buddle the ores, mi.xing the resulting smalls incongruously together; but a judicious sorting should be commenced at the wash kilns, and upon this basis the various sizes kept distinct whilst passing through the washing floors. The dresser should also take care to keep the several ranges of mineral produces and degrees of fineness together. The following general deductions will be found serviceable : — First. — Absolute perfection in separation according to specific gravity cannot be arrived at, chiefly on account of the irregularity of form of the various grains to be operated upon. Second. — The more finely divided the stuff to be treated, the greater is the amount of labor and care required, and the more imperfect will be the separation. Third. — That reducing machine maybe considered the most perfect which produces the least quantity of stuff finer than that which it is intended to produce. Fourth. — It is necessary, in determining the degree of fineness to which a mineral should be reduced, to consider the metallurgic value of the ore contained in it, and to set against this the value of the loss which will probably be incurred, together with the labor and expense attendant upon the manipulation. Fifth. — The vein stuff should be reduced to such a degree of fineness that the largest proportion of deads and clean ore should be obtained by the first operation, thus saving the labor and preventing the loss incident to a finer subdivision of the ore and more extended treatment. Sixth. — That apparatus or plan of dressing may be considered the most efficient which with stuff of a given size allows at an equal cost of the most perfect separation, and of the proper separation of stuff of nearly equal specific gravity. The average percentage to which the crop is to be brought, and the highest percentage to be allowed in the castaways being determined, it is evident that the more perfect the degree of separation the greater will be the amount of crop and castaways obtained at each operation, and the quantity of middles or stuff to be re-worked will be diminished. Seventh. — We may further consider as a great improvement in dressing operations such apparatus or plan of working as will allow, without a disproportionate increase in the cost, of the equally perfect separation of fine stuff as that of the coarser, as now practised This will be of especial benefit in the ca.se of finely disseminated ore, which is necessarily obliged to be reduced to a great degree of fineness. Washing and Separating Oues. The vein stuff, on arriving at the surface, is not onlj' associated with a large amount of gangue, but is frequently much intermixed with clay, rock, and siliceous matter. In order to get rid of the latter substances, it is usually washed and picked. The wash- ing apparatus ought to be so contrived as to allow the cleansing to be effected both cheaply and expeditiously, and for this purpose a good volume of water is always desirable. If a height or fall can be obtained, it will also be found advantageous. In accordance with the character of the ore the apparatus will have to be varied ; but for lead, certain varieties of copper ore, as well as iron, or other abundant ores, the kiln is well adapted. In many mines rectangular grates are fitted to the bottom of the kilns, but a perforated plate would b(! found to furni.sh better results, since the former allows of the passage of flat irregular masses of stone, rendering the treatment in the jigging sieves less successful. The holes in tlic perforated plate should be conical, the largest diameter underneath, so that the stones may have unobstructed passage. In connection with the kiln-plate a sizing trommel should l)(! used, and in order to economize both time and expenditure it would be judicious to introduce the vein stuff, and discharge the castaways by means of railways. The picking of the stuff is a highly important operation. As a rule all picked ore should be selected, and the dradge (lei)iived of the largest possible amount of waste before it is sent to the crusher. It is highly fallacious to suppose, because machinery will deal with large quantities expcMlitiously, that it is cheaper to subject the mass to its action ; on the contrary, if correct calculations are made of the losses which will ensue on the initial est dradge ore. An expert cobber will manage to pass through her hands about ten hundred weights of tolerably hard stuff per ten hours. Si.ziiig Apparatus. — In the varied processes of dressing, no point is of greater importance than that of correctly sizing the v^'in stuff, neither is there one demanding the exercise of a more c irrect judgment. If the particles of ore be reduced below their natural size, a source of loss is immediately created, whilst, if they are not brought within the limit of their size, a portion of waste will probably adhere to cacli atom, forming a serious difference in the aggregate quantity of castaways, althougli sucli waste may afford ))ut a low average percentage. The holes in the sieves or tronmiels sliould therefore be proportioned to the nature of the ore, but such apparatus should also be introduced wherever necessary. To the crushing-mill, trommels art; essential, whilst it will be found highly advantageous to cniploy them for the purpose of dividing (he stnlf wher- ever it may become intermixed Tl)e simplest form of sizing is jjerliaps hy the hand rid- dle, Jig. 474, which is formed of a circular hoop of oak, 2 of an inch thick and six inches d-ep. Its diameter ranges from eigliteon to twenty inches. 8U ORES, DRESSING OF. The bottom is made of a meshwork pf copper or iron wire. The weight of an iron wire riddle is about seven pounds, and its cost 4s. 6d. I ^;<^/^^:4*«-^f^;;;'r F?g. 475 represents a swing sieve employed in the mines on the Continent, a, box into which the stuft' to be sifted is introduced ; 6, regulating door ; c, pendulating rod attaching the sieve frame to the frame e ; /, friction roller carrying the sieve frame ff. At A springs are fitted to each side of the frame, in order to give it a vibratory action, i, rod, giving mo- tion to the apparatus. The width of the sieve frame is about one-third its length, but the sieve bottom only extends from the box a two-thirds of the length. The bottom of the sieve frame is subsequently contracted so as to form a shoot. At the extensive mines of Comorn, near Duren, these sizing frames are largely employed in connection with stamping- mills. The circular hand-riddle has only recently been introduced into the mines of Cornwall. Although this is in advance of hand riddling, yet it is by no means equal to the large sizing trommels employed in Germany. The ore is thrown in at a, Jig. 476, the coarser pieces passing longitudinally through the 476 riddle into the shoot b. The riddle is turned by a hook handle, as shown in the illustra- tion ; tlie meshes of the sieve vary from f of an inch to one inch square, according to the character and quality of the vein stuff to be operated upon. Fiffs. 477, 478 show an elevation and ground plan of a series of flat separating sieves. A a', B b' is a strong wooden frame ; m m, guides for frame ; n n n, basement upon which the sieve frame rests ; p, cistern fitted with perforated plate through which clean water is distributed upon the sieves ; t, hopper supplying the stuff to be sifted ; s s bottom of ditto. The sieves are lifted by the rod /, and make from 40 to 50 beats per minute. The sieves are set about eight inches apart, and discharge the stuff' upon the inclines p p p. The holes in No. 1 sieve are ^ inch diameter. "2 t " 3 7.6 The apparatus is employed in the Clausthal Valley. Fig. 479 represents the trommel or sizing sieves in operation at the Devon Great Con- sols. Although the yield of ore at these mines is extremely large, it may not be generally known that nmch of it is obtained from stuff yielding no more than from f to H i)er cent, of metal. The product of the lode on arriving at the surface is cobbed and divided into two classes, the first going to market without further elaboration, whilst the dradge or infe- rior portion is treated l)y various processes of washing. The whole is however crushed to such a degree of fineness as to pass through the followiug_ holes : — ORES, DRESSING OF. Trommel a, boles '/ao inch diameter. ") hi " C, " Vio 845 ■ .^^^\«^' rli. Jil!.*T,™''' "n ^'''''' t^^""^ '""- "^ '"^^*^^ d''^™^^*^'- »t tf'^^ '"'•Kc end, and 18 inches %1%1 s'uterS ""'.'"^ '' "^^'"^*°"^ P^^ ™'""^^' '^"^ ^'^^s'ther affording ante" 846 ORES, DRESSING OF. Crushing JIachixery. Various crushing machines are described under Grinding and Crushing Machinery ; but it may be observed that this section of the dressing department deserves careful attention, as the results are more or less ati'ected according to the mode of working and adjusting this class of machinery. The crusher is, as it were, the starting or radiating point for treating the dradge work, and if considerable care is not exercised hero, not only will there be much loss of power, but also of the initial quantity of ore. In the mining districts of this coun- try it is usual to introduce rough and fine dradge together ; no preliminary division of the stuff is attempted ; the hopper is continuously charged, and that portion which is not re- duced sufficiently fine is returned by the raft'-wliecl to be recrushed. The consequence is, the motion is uneven, strains arc inflicted on the machinery, and more time as well as power is necessary for the purpose of realizing a given result. Valu- able improvements could be effected by first mechanically sorting or dividing the dradge, expediting the speed of the rolls, fitting them with steel faces, setting them so as not^o reduce the grain of ore below its normal size, giving them a uniform supply by means of a tilting shoot, and instead of returning the raff to tlie rolls conveying it to a second series of smaller dimensions, adjusted and managed in a similar way. To each set of rolls there should be fitteu sifting trommels, with holes pioportioned to the character of the ore, whilst in many instances it would be found judicious to discharge a stream of water on the rolls with a view of expediting the crushing. In small mines, buckbuj, jig. 480, is resorted to instead of employing the crushing-mill. 480 481 This operation consists of pounding pieces of mixed ore on a slab of iron a, by means of a hammer og bucker b. The wall on which the plate a is placed, is about 3 feet high. The stuff to be pounded is placed behind tlie slab, and is drawn upon and swept off the plate by the left hand. In Cornwall it is customary to keep time with the blows and to stand to the bench, but in Derbysliire each operator works independently, and is usually seated. * The bucker, fig. 481, is formed of a wrought-iron steel-faced plate a, 3 inches square, with a socket b, for receiving a wooden handle c. Its cost i§ about Is. 4J. Stamps. Tin and some other of the more valuable ores are usually associated with and minutely disseminated in a hard crystalline gangue, requiring to be reduced to a fine powder before the valuable portions can be extracted. Various contrivances have been employed for this purpose, but none of them seem to have entered into competition with the stamping-mill. This apparatus essentially consists of a number of cast iron pestles, each measuring about 20 inches high, and 6 by 10 mches in the section. These are secured either to a wroug!it-iron or wooden lifter ; a projecting arm is placed towards the top on each lifter, whiih may be slidden up and down so as to meet the wear of the pestle or any other irregularity. These lifters are retained in their vertical position by suitable metal or wooden supports. Motion is communicated by a revolving shaft in front, fitted with four or five projecting cams, each of which catcl.es the arm, and lifting the pestle from 8 to 10 inches, lets it suddenly fnll on the substances which may be underneath. The bottom on which the heads fall is formed by introducing hard stones or other suitable material, and pounding it until it becomes sufficiently solid. In most parts of the Continent of Europe, on the contrary, stami)ing-mills are provided with solid cast-iron bottoms ; these are, however, subject to the inconvenience of requiring fre- quent renewal. Around the pestles a wooden box or cofer is constructed, and covered in at tlie top ; the back is partly open at the bottom in order to admit the vein stuff. On each side one, and in front two openings are made, 7 or 8 inches square, which ^re fitted with wrought-iron ORES, DRESSING OF. 847 lV.i:ne.s, for the reception of perforated iron, copper, or brass plates, the bur of the punch or drill being towards the inside. As a precaution against the speedy destruction of the cofer from the constant scattering of fragments of stone, the inside is partially lined with sheet-iron. The stuft" to be stamped is supplied on an inclined plane, connected with a hop- per at the back, in the front of which is a launder for affording a stream of water to the cofer. The stamped stuff passes through the grates into launders, and is thus directed to the floors. When water is the motive power, the number of heads is limited by the volume and fall of water available ; three heads are the least number used, but a larger number is generally preferred. When steam-power is employed, a battery of heads sometimes includes 100 or more pestles. When in action, these are elevated from 40 to 80 times per minute, according to the character of the stuff to be reduced. The pulverization is said to be greatly facilitated by having four heads in the same chest or cofer, about 24^ inches apart. Each head is lifted separately, and the cams by which this is done are so disposed on the axle as to make the blows in regular succession. Great care is also taken whether it be in a large or small battery, to prevent any two pestles falling at the same instant ; the object being to secure an equal strain against the power. Practical dressers are not well decided as to the order in which the lifting of four heads in one cofer should take place, whether one of the inner pestles should precede the other, or whether a side pestle should be first lifted. A preference, however, seems to be given to the following method : — supposing a spectator to stand in front of a 4-head stamps, left side pestle first, right side second, right middle third, left middle last. Fig. 482 represents the elevation of a steam stamps employed in Cornwall, a, axle ; 482 n, cams for lifting heads ; c, tongue or projection on lifter; D D, guides for retaining lifter; E, the lifter ; f, he;id or pestle ; g, chest or cofer ; ii, hopper ; j, pass connecting cofer and hopper ; k, launder discharging water into the cofer ; l, stamps grate ; m, launder receiving the stuff which has been flushed through the grates ; n, the bottom or bed of stamps. The stamping process is not so simple as it may appear at first sight. Many of its par- ticulars, such as the form of the cofer, mode of exit for the stuff, weight and rapidity of the pestles, and quantity of water employed, must be varied to suit the mode of dissemination and the structure and character of the ore, as well as of the matrix. Fineness of retiuction is l)y no means always a desideratum, for if some kinds of stuff" be reduced too low, much of the ore contained in it will be w.isted, hence considerable judgment is necessary in select- ing the grate best adapted to the stuff to be operated upon. Sometimes the grate is re- placed by the " flosh," which consists of a small hopper-shaped box, fitted to the front of the grate-hole. This box is provided with a shutter, which is raised or lowered according as the ore is required in a fine or rough state. In dry stamping the fineness of the powder depends not on the grate, but on the weight of the pestles, the height of their fall, and the period of their action upon the substances beneath them. The following practical results are derived from the steam stamps at rol))erro Tin Mines, Cornwall : — Cylinder of engine, 86 inches diameter. Diameter of the fly-wheels, 150 feet. Weight of ditto, with cranks, shaft, and bolts, A1\ tons. Power employed, 55 horses. Reduced in 12 months, 30,201 tons of vein stuff. 848 OPwES, DRESSING OF. Average number of revolutions of stamps axles per minute, 8^. Number of heads lifted per minute, 12, each 9 inches high. Weight of each head, 600 lbs. Average number of blows performed by each head, 45. Weight of heads collectively, 19^ tons. Number of grates, 72. Exposed area of front grates, 9 x 6 = 54 inches. Ditto of end grates, 8 x 6 = 48 inches. Number of "holes to the square inch, 140. Co,«t of stamping, including maintenance of engine and wear and tear of machinery, Is. Zid. per ton of stuff. Jigging Machinery. In the jigging sieve only the initial velocity of the substances to be separated is ob- tained at each stroke. Were, however, the sieve plunged to a depth of say 20 or 30 feet, the various grains would settle themselves according to their various velocities of fall, one over the other, assuming them to be of a uniform size. The following table, furnished by Mr. Upfield Green, shows the fall of various spheres in water in one second, the depth being in Prussian inches : — Diameter Lines. Gold. Spec. Gr.iv. 19-2 Prussian Inches. Galena, Spec. Gr.iv. T-5 Prus.sian inches. Blemle. Spec. Grav. 4 Prussian inches. Quartz. Spec. Grav. 26 Prussian inches. 8- • 100- 60-093 40-825 29-814 5-657 84-090 50-532 34-329 25-071 4- 70-711 42-492 28-868 21-082 2-828 59-460 35-731 24-275 17-728 2- 50- 30-046 20-412 14-907 1-414 42-045 25-266 17-165 12-535 1- 35-355 21-246 14-434 10-541 0-70. 29-730 17-866 12-137 8-864 0-5 25- 15-023 10-206 7-454 0-354 21-022 12-633 8-582 6-268 0-25 17-678 10-623 7-217 5-270 Now, instead of assuming the substances to be of a uniform size, let it be supposed that they vary ; the foregoing table will show that gold of 8 lines would settle at bottom, and that when gold of 2-9 lines began to settle, the galena of 8 lines would fall also. With galena of 3| lines, blende of 8 lines would be associated, and so on. If, secondly, it be assumed that the substances varied between 4 and 8 lines, some time would elapse, after gold of 4 lines had settled, before the galena would begin to deposit itself. With blende; however, of 4 lines, and quartz of 8, the latter would almost appear at the bottom at the same time. The proportion between the maximum and minimum sizes of the stuff to be operated on should be as the specific gravity of one to the other. Thus, Gold and galena 7-5 : 19-2 : : 1 = 2-56 Galena and blende 4-0: 7-5 :: 1 = 1-075 Blende and quartz 2-6 : 4-0 : : 1 = 1-537 Hand Sieve. — This apparatus, fie/. 483, is formed of a circular hoop of oak, f of an inch thick and 6 inches deep. Its diameter ranges from 18 to 20 inches. The bottom is made of copper or iron wire meshes, of various sizes. Sometimes perforated copper plate is employed, when the sieve is termed a copper bottom. The sieve is shaken with the two hands in a cistern or tub of water ; an ore vat is however sometimes employed, and either fixed horizontally or in an inclined position. In using this sieve the workman shakes it in the vat with much rapidity and a dexterous toss till he has separated the totally sterile por- tions from the mingled as well as from the pure ore. He then removes these several quan- tities with a sheet-iron scraper, called a limp, and finds beneath them a certain portion of enriched ore. 483 484 J^^ Deluinr/ Sicve.-^This sieve, a, fff. 484, is either constructed with a hair or canvas bot- ORES, DRESSING OF. 849 torn ; the former is more expensive, but more durable. Its peculiar application is chiefly for the final treatment of ores previous to being put to pile, such ores having first passed through the finest jigging sieves, yet still maintaining a certain degree of coarseness, and bearing a high specific gravity. In the separation of ores from .light waste, or such minerals as approach one another somewhat closely iu their densities, this form of sieve is both good and effective, but to use it properly a considerable amount of dexterity and practice is requisite. There are two principal methods of using it ; by one a motion is given, whereby the waste is being constantly projected and carried over the rim into the kieve by a current of water forced through its bottom. This mode of treatment is adapted for poor ores. In the second case, when the ore is nearly pure but still associated with a heavy gangue, a motion is given to the sieve whereby the water is forced through the ore, and made to traverse the surface of the mineral in concentric circles. This motion collects the waste into the middle of the clean re- sult. By the first method about six tons per day may be passed through by each workman and enriched for the second operation. The weight of the sieve varies from four to five pounds, its diameter is twenty iix inches, depth four inches, and cost from 2s. 3d. to 2s. 6c?. A jigging sieve, constructed as shown in Jig. 485, is sometimes employed on the Continent, x represents the table on which the mineral is placed ; b is a large kieve of water, in which the sieve is sus- pended by the iron rod d, set in motion by means of the arrangement, f, g, h, sus- pended at I, and having at the extremity H a box for the reception of small stones, to be used for the purpose of counterpois- ing the weight of the sieve and several fittings. By moving the rod f, sliding in K, the workman gives the required motion to the sieve, and when its contents have been sufficiently washed he removes them by the same means as when the hand sieve is em- ployed. I{a7id Jigging or Brake Sieve. — The brake sieve, Jig. 486, is rectangular, as well as the 486 cistern in which it is agitated, a, wooden lever, having its axis at f ; n, piece of wrought- iron bolted to end of lever a, whilst its upper end passes freely through a slot opening in lever n, and having two shoulder projections c ; e, axis of lever d ; g, bars connected with lever d, supported on axle e, and from which the iron rods h ii deiiend ; j, rectangular sieve ; k, under hutch ; l, shoot for overflow of water ; m, receptacle for retaining any fine, Vor,. III.— .54 850 ORES, DRESSING OF. ORES, DRESSING OF. 85] ore which may escape with the water from l, as well as for receiving the hutchwork. A boy placed near the end of lever a, by the action of leaping, jerks it smartly up and down, so as to shake effectually the sieve j. Each jolt not only makes the fine part pass through the meshes, but changes the relative position of those which remain in the sieve, bringing the purer and heavier pieces eventually to the bottom. The mingled fragments of ore and stony substances lie above them, while the poor and light pieces are at the top ; those are first scraped off by the limp, then the mixed portion, and lastly the ore, which is usually car- ried to the ore heap. The sieve frame may be made 2x4 feet inside and 8 to 9 inches deep The hutch should then be 5 feet long, 3^ feet wide, and 4| feet deep, constructed of good deal boards 2 inches thick. The quantity of stuff which a boy can jig in ten hours will depend upon several circumstances. With a sieve six holes to the square inch and a tolerably light waste, from five to six tons can be operated on. Machine Jic/rjiug. — The machine jigger represented in Jig. 487 is constructed on the same principle as the hand apparatus. The hutches are, however, somewhat larger, being six feet long, four feet wide, and four feet deep, a, fly-wheel ; b, driving-wheel ; c, cog- wheel receiving motion from b, and giving motion to a crank from which depends a rod attached to lever d. m e, the vertical rod, passes through a slot opening in the wooden lever f, and by these several combinations a vertical movement and jerk is given to the sieve contained in the cistern g. When it is required to discharge the sieve, the lever h is depressed, and the pin, not seen in the end of lever f, traverses in the slot shown in the bridle rod immediately below the bracket. The sieve measures 4x2 feet and 9 inches deep. It is strengthened by iron bauds and numerous slips across the bottom. A jigging apparatus, fig. 488, has been arranged by Mr. Edward Borlase, of St. Just, Cornwall, and introduced by him at Allenheads,.with satisfactory results. At these mines it has been worked in conjunction with the machine, fig. 496, and described at page 857. The larger and denser portion of stuff separated by this apparatus is conveyed by suitable launders to a series of sieves, arranged on the top of a conical reservoir, furnished with a feed pipe for the admission of water, and with an outlet pipe at the bottom. This reservoir is placed within another reservoir, also in the form of an inverted cone, and provided with an outlet pipe at the lower part, a, eccentric giving motion to the sieve ; b, launder con- veying stuff to such sieves ; c, distributor, either stationary or revolving, as may be re- quired, delivering stuff to the sieves arranged on the top of the conical reservoir ; f, valve for discharging the finer portion of the ore ; G G, internal cistern furnished with an outlet valve H. The sieves have a slight outward inclination, and the refuse substances with the waste water are carried over and deposited in the conical cistern, G g. The sieves should make from 150 to 200 pulsations per minute, according to the quan- tity and character of the stuff under treatment. The following is the result of trials made on 160 tons of stuff, one-half being delivered to Borlase's machine, the other to the common jigging hutch : — Difference in Machine. Hutchers. favor of Bor- lase's Mucliine. 1 Time .— Hours. Hours. Hours. Occupied hutching cuttings 50f 68^ Vi Ditto smiddum from do. 5 lOi 6i Sludge machine, washing sludge and smid- dum - - 2H I Dressing the ore in a trunk ... 29i 61H lOi 1 Aggregate number of hours occupied bv the lads in doing the work, viz., feed- ing cuttings and hutching smiddum IIU 195f 84i Aggregate number of hours occupied by the lads in wasliing sludge and smid- dum, including the final cleaning in a trunk -...-.. 102 123 21 Cost :— £ s. d. £ s. d. £ s. d. Of boys attending mftchinc, wheeling away waste, and preparing ore for the bing-stead 1 1 15 9 2 8 9i 13 Oi 852 ORES, DRESSING OF. Produce : — Borlase's machine Hiitchers Difference in total produce in favor of Borlase's ma- chine Ditto ditto - Sieve and Smlddum Ore. Sludge Ore. Total Ore. Total Lead. St. lbs. Assay. Lead. St. lbs. Assay. Lead St. lbs. St. lbs. 19 10 17 6i p. cent. 60 60 lbs. 165-6 146-7 32 5f 13 p. cent. 70 64 lbs. 317-6 116-5 52 If 30 6i 21 9i 71 p. cent. 34 71 18 Hi 15 10 84 p. cent. Petlicrick^s Separator. Figs. 489 and 490. a, the plunger or force-pump ; b, recep- tacles fitted with sieves ; c, hutch filled with water ; d, discharge holes fitted with wooden 489 4 00 plugs ; E, movable plate to admit of withdrawing the ore ; f, hopper with shoots for sup- plying sieves ; n, beam for giving motion to plunger piston a ; j, launder for delivering water to hutch. ORES, DRESSING OF. 853 About the year 1831, Mr. Petberick introduced the above machine at the Fowey Consols Mines in Cornwall. It was described in the Quarttr/i/ Miuing lierinr^ January, 1832, from which the following is extracted : — This machinery is particularly intended to super- sede the operation oi jigging in separating ores from their refuse or waste. * * * In the separators, the sieves containing the ores to be cleaned are placed in suitable apertures in the fixed cofer of a vessel filled with water, connected with which is a ()lunger or piston working in a cylinder. The motion cf the plunger causes the water to rise and fall alter- nately in the sieves, and effects tne required separation in a more complete manner than can be performed by jigging. The variety in the extent and tjuickness of the motion required for the treatment of different descriptions of ores is easily produced by a simple arrange- ment of the machinery. A principal advantage in this separator is derived from (he sieves being stafionary (in jigging, the sieve itself is moved) during the process ; thereby avoiding the indiscriminate or premature passing of the contents through the meshes, which necessarily attends the operation of jigging, whether by the brake or hand sieve. Greater uniformity of motion in the action of the water, in producing the required separation, is also obtained ; and supe- rior facility afforded to the deposit in the water vessel (especially in dressing crop ores) of the finer and richer particles, which in jigging are principally carried off in the waste water. The superiority of the patent separators over the ordinary means of cleaning ores will perhaps be best shown by reference to their actual performance. At tlie Fowey Consols and Lanescot mines in Cornwall, where they are extensively used, seventeen distinct experiments have been made on copper ores of various qualities from different parts of the mines, to ascertain the extent of the advantage of this mode of separation over the operation of jig- ging. Seventeen lots of ores, amotmting together to about 300 tons, were accurately divided, one-half was jigged, and the other half cleaned by the separators. A decided advantage was obtained by the latter, in every experiment ; the following are the aggregate results : — Quantity of Marketable Ores returned. Percentage of Metal. Quantity of Metal. Value of Ores. R.v jigging - By the separators - Tons. Cwt. Qrs. 76 19 74 19 8i Tons. cwts. qrs. lbs. 5 19 2 3 6 9 18 £ ><. d. > 362 1.5 7 396 6 7 1 Difference in the Value of Ores. In the Labor of Cleaning. Total. Being 9.9 8d. per ton, on 74 tons 19 cwt. £ «. d. 33 11 £ s. d. 2 11 4 £ 8. d. S6 1 4 It must be obvious to those who are practically acquainted with the subject, that the poorer the .stuff containing the ores, the greater must be the relative value of any improve- ment in the process of cleaning it. This has been satisfactorily demonstrated by the trials which have been made in the mines before mentioned, in dressing the tailings, which are the refuse of the inferior ores, called halvans. It appears that these tailings may be dressed by the separators with more than treble the profit to the proprietors, which could be real- ized by the ordinary methods ; and there is no doubt that there are vast quantities of sur- face ores, both copper and lead, in various mines, which might be dressed by the same means with consideratjle advantage. Edwards Sf Beaclicra Patent Mineral and Coal-Washing Machine, consists of two cis- terns, rectangular in horizontal section. Within a few inches of tlie top of these, jierforated plates or screens, e, fg. 491, are fixed, upon which the material to be washed is fed through a hopper, which also connects the two cisterns. On the inner sides of the cisterns are two apertures closed by flexible discs, or diaphragms of leather, c, which, when the machinos are filled with water, cause it to rise and fall tln-ough a certain space, by means of a hori- zontal vibratory motion, which they receive from an eccentric on a shaf^t, which is driven either by a steam engine attached directly to it, or by a driving-belt and pulley, a. See Wasiii.ng Coal. The action of the flexible diaphragms is similar to that of cylinders and pistons, which are sometimes substituted for them. Above the driving-shaft is a smaller one, B, which is driven at a slower rate by means of toothed wheels, and gives by cranks or eccentrics a horizontal motion backwards and forwards to sets of scrapers k, above the cisterns. These are so arranged as to remove the upper stratum of the sul)stanco being acted upon, and dis- charge it into wagons or other convenient rccei)tacles ; these up])er strata are of course the lightest, the heavier part settling upon the perforated jjlates below. 854 ORES, DRESSING OF. 491 "When from the action of the machine a considerable quantity of material has accumu- lated upon these plates, the scrapers are thrown out of gear by means of apparatus attached, H II, and the stuff raked off, the operation being then continued on fresh supplies. Doors, G G, at the bottom of the machines, admit of any fine stuff which may pass through the per- forated plates being removed from time to time as may be necessary. These machines are in use for cleansing coal as well as other mineral substances. In such cases the heavier stuff which remains upon the plates consists of shale, pyrites, &c., very injurious substances in the manufacture of coke. One machine of two connected cisterns, is capable of washing about thirty tons per diem of coal, but the quantity of min- eral work will depend upon the amount of ore present in proportion to the waste. The size of the perforations in the screens is adapted to the quality of the material acted upon. A gold-washing machine has been arranged by Mr. John Hunt, late of Pont-Pean, France. This gentleman states that it requires but little water, and is so contrived as to circulate this water for repeated use ; also that the principle would be found very successful if employed on a more extended scale ; this Mr. Hunt intends to carry into operation at some lead mines in Cornwall. Separators. Of late years apparatus of this class has been steadily coming into operation, not only in lead and copper mines, but also in the dressing of tin ores. The prevailing principle is that of directing a pressure of water against the density of the descending material, making the former sufficiently powerful to float off certain minerals with which the ore may happen to be associated. "When marked difference of densities exists, and the ore can be readily freed from its gangue, this mode of separation v.ill be found effective. Trommels may be advantageously employed for sizing the stuff" previous to its entry into the several sepa- rators. Slime Separator. — This apparatus is due to Captain Is.aac Richards, of Devon Great Con- sols, and is employed for removing the slime from the finely-divided ores which have passed through a series of sieves set in motion by the crusher. The finely-divided ores are for this purpose conveyed by means of a launder upon a small water-wheel, thereby imparting to it a slow rotary motion. "Whilst this is turning, time is allowed for the particles to settle in accordance with their several densities ; the result obtained is, that the heavier and coarser grains are found at the bottom of the buckets, whilst the lighter and finer matters held in suspension are poured out of the buckets and flow away through a launder provided for that piirpose. The stuff" remaining in the bottom of the buckets is washed out by means of jets of water obtained from a pressure-column ten feet in height, and passes directly into the funnel of a round buddle. The wheel a, fir/. 492, is four feet in diameter, two feet six inches in breadth ; has twenty-four buckets, and makes five revolutions per minute ; b, launder for supplying the finely-pulverized ore ; c, pressure-column ; n, jet-piece ; e, launder for conveying off' the slime overflow of the wheel ; f. launder for conveying roughs to round buddle. A modifi- cation of tl'.is apparatus is employed at the Wildberg mines in Germany, where it has been recently introduced, and is found to succeed admirably for the classification of finely-divided ores. ORES, DRESSING OF. 492 855 493 Sizing Cistern. — The tails from round buddies are sometimes passed through this appa- ratus. It consists, fig. 493, of a wooden box provided with an opening at the bottom, a, which is in communication with a pres- sure-pipe, B, an outlet, c, and has a small regulating sluice, d. The stuff from the buddies enters at E, and the pressure in the columns is so regulated as to allow the heavier particles of the stuff to descend, but at the same time to wash away at f the lighter matters that may be associated with the ore. This is done by having the outlet c of less area than the inlet, and fixing on the extremity d a con- venient regulating sluice, by which means a greater or less quantity of stuff may be passed over the depression f. Two cis- terns of this kind are generally employed, the second being used to collect any rough particles that may have passed off from the first. The depth of the first of these boxes may be eighteen inches, its width thirteen inches, and its length three feet six inches. The dimensions of the second may be considerably less. The arrrangement of another separating box is shown in figs. 494 and 495. The slime water flows in at m ; and water still holding a considerable portion of slime flows away from the opposite end. It is necessary that pieces of chip, small lumps, or other extraneous mat- ter, should be intercepted previous to entering this apparatus, also that the slimes should be evenly sized by means of a trommel or sieve. The heaviest portion of the slime water in which the sand and ore are contained, is discharged at o, which is about an inch square. The launders p p are for the purpose of conveying the slime water either to buddies or shaking tables. The dimensions of the cistern No. 1 are, length, six feet ; width, one and a half feet ; depth, twelve inches. But two other cisterns of .similar form are attached. No. 1 cistern will work about ten tons of stuff in twenty-four hours, and by widening the box from eighteen to twenty-seven inches, it will get through twenty tons in twenty-four hours. Affixed to one side of the boxes are hammers so contrived as to give thirty blows per minute in the manner of a dolly tub. The sides of the box have an angle of fifty de- grees from the horizontal. The chief dimensions of the two cisterns, viz., one working ten and the other twenty tons, are subjoined. No. of Box. Ten tons. Twenty tons. Lcticth of Box. Breadtli of Box. Depth of Box. Length of Breadth of Box. Box. Depth of Bo.x. 2 3 4 ft. 9 12 15 ft. 2 4 8 ft. C 8 10 ft. { ft, 9 1 5 12 1 9 IG 1 15 ft. 6 8 ! 10 856 OKES, DRESSING OF. 494 I- ,>h ^^ ^/V < According to experiments made in the Stamping-house of Schemnitz, where twelve tons are stamped in twenty-four hours, the first cistern separated from the slimes 40 per cent, of the ore ; the 2d cistern, 22 per cent. ; the 3d cistern, 20 per cent. ; the 4th cistern, 12 per cent. ; together, 94 per cent., leaving a loss of 6 per cent. From No. 1 box every cubic foot of water flowing through gave 16 pounds of sandy matter. No. 2 afforded 13 pounds of finer stuff. No. 3, 16 pounds, and No. 4 yielded 12 pounds per cubic foot of water. It should be remarked that the outlet o is proportioned to the dimensions of the machine. Borlase^s Machine, jig. 496, has been recently introduced at the Allenheads Mines, be- longing to Mr. Beaumont. The ore and mineral substances, after passing through the crushing apparatus, are introduced at a, and flow through the spaces b b, passing into c c. At the bottom is a circular chamber e e, with a perforated cylindrical plate f. Water under pressure is supplied by the pipe g, and regulated by the cock h. It will be seen that this apparatus consists of an external and internal cone with a space between them, and that a separation of the orcy matter is effected by limiting the power of the water between the density of the stuff to be retained, and that which is to be dis- charged at J J into the shoot k. At L the larger and denser portion of the mineral which has fallen through the ascend- ing current of water, is conveyed either to a jigging machine or some other enriching appa- ratus. Mr. Borlase first erected this apparatus in the United States of America, where it was found to answer remarkably well, and he was induced by this success to attempt its gen- eral introduction in this country. In this endeavor he has not, however, been as yet so entirely successful as could be wished, as the English mines, and particularly those of Corn- wall, are for the most part managed by individuals who require to be fully convinced of the utility of any new invention before giving it a trial. This machine has been employed with great success at the mines of Allenheads. The comparative results afforded by Borlasc's Trunking Machine and the common Nicking Trunks may be seen from the following statis- tical statement. ORES, DRESSING OF. A ../ 496 857 Lead Mines, Allehneads. Results of trials with Borlase's 4^ feet Circular Lead Ore, Sludge, and Slime Dressing Machine, and the common Nicking Trunks, March, 1859. Fortj'-four wheelbarrows full of exactly the same description of slimes were put through each of the respective processes. Machine in operation - Occupied in oiling machinery Ditto emptying ... Stirring, nicking, and empty- ing trunks - - . . Occupied dollying the work - Labor of men and boys em- ployed .... TIME. Borlase "s Machine. Trunlis. Difference. ! Hours. 15 2 1 Minutes. 16 40 37 19 Hours. Minutes. 14 3 2 Hours. Min. ! i j 0, 19 52 16 3 3 49 COST. £ s. d. 4 3* £ s. d. 8 8 £ 8. d. 4 5 PROnUCE. Ore. Lead. Ore. Lead. Ore. Lead. St. lbs. Ass-iy. lbs. St. lbs. Ass.iy. lbs. St. lbs. St. Ibs.j Best work - . • - Seconds .... Thirds Fourths .... 54 in§ 10 3i 21 9^ 22 9 p. cent. 65 46 30 8 498-3 65-9 91-0 25-4 53 9i 11 12 34 2-1 p. cent. 64 46 12 180-8 76-4 51-4 109 4t 680-6 99 9f (•)14-0 9 8| 4 1(1 * The cost is unduly heavy, the same value of labor would have maintained three m.ichines. 858 ORES, DEESSING OF. Fig. 49Y represents a wooden cistern a, having an aperture b at the bottom, about an inch diameter, which is alternately closed and opened by means of an iron plate c, fitted upon the vertical shaft, to which is also fixed an iron paddle d, which revolving horizontally keeps the ore and water in con- stant agitation. The tails from the various buddies, as well as the stuff from the cofers at the end of the strips, flow in at e, and pass through a perforated sizing plate f, into the cistern. The rougher and heavier portions escape through the hole B into a strip where it is continually stirred, in order that it may be evenly deposited, and at the same time freed from the lighter particles. The overflow containing fine ores passes by the launder g into catch pits, from which heads and middles are taken to be elabor- ated by means of buddies or other appara- tus. \Vhen this separator is employed in tin dressing, it is usual to divide the stuff in the strip connected with the bottom of the box, into heads and tails. The first is taken direct to the stamps, and again pul- verized with rough tin stuff; but before the tails can be so treated, they are re- stripped in order to get rid of extraneous matter. Wilkin^ Separator. — This apparatus is the invention of Mr. J. B. Wilkin of "Wheal Basset and Grylls, near Helston. He describes it as a " self-acting tossing-niachine, by which the rough particles are separated from the fine and prepared for the inclined plane. The orey matter is carried into a small cistern by a stream of water which enters at the top and passes out at the opposite side bearing the finer particles with it, whilst the rougher and heavier particles escape at the bottom through a rising jet of clean water, which prevents the fine and light particles from passing in the same direction." a, fig. 499, inlet of clean water; n, launder delivering the orey matter; c, outlet of fine and inferior stuff; d, dis- charge orifice for rough and heavy stuff. This operation must be regulated by a flood-shut. A cistern 10 feet square on the top, and 18 inches deep, will pass through about 40 tons in 10 hours. When separating stamps work a smaller cistern is employed, say 14 inches square, 10 inches deep ; this will despatch 6 tons in 10 hours. A valuable form of separator is shown in fig. 500, the peculiarity of which consists in the manner of introducing the water and slimes. Instead of the latter depending for sepa- ration upon the power of an ascending column of water, it here passes into a horizontal flow of greater or less volume and velocity, produced by altering the tap g. Compart- ments, viz., 1, 2, 3, and 4, are also fitted in the box, for the purpose of receiving mineral of different densities and size, which is discharged and washed in strips set underneath ; a, inlet launder to trommel ; B, waist of sheet-iron ; c, trommel either of perforated plate, or wire gauze ; d, shoot from trommel serving to convey away the rougher portions ; e, hop- per for conveying stuff to shoot h, and from thence into the box ; f, ascending column of water ; g, tap for regulating the flow of water ; k, l, m, n, outlet pipes for delivering the OKES, DRESSING OF. 859 separated stuff to strips or buddies ; o, launder for receiving overflow from cistern ; p, Q, r, valves regulating the width of the compartments, also for the purpose of effecting the dis- position of the different minerals with which the ore may be associated. 500 In addition to the machines already described, a slime or sludge-dressing apparatus has been designed by Mr. Borlase, and which he intends to introduce into the mining districts of this country. Fig. 501 represents an elevation, and jig. 502 a plan of this machine. It is described by the inventor as follows : — The mineral from which it is desired to sep- arate the metallic ore having been crushed or pulverized, is conducted through a pipe or channel into a revolving cylindrical sieve, a a. The larger ])art6 pass into a shoot or laun- der, B, and from thence into a self-acting jigging machine. The slime or fine portion passes through the meshes of the sieve into a shoot, c, and is discharged into an annular launder, from whence it falls cither into a stationary or revolving distributor, d d. From thence it SCO ORES, DRESSING OF. flows through guitable channels into the outer part of the machine, e. The apparatus is fixed on a perpendicular axis, f, and is kept in a continual oscillatory motion by means of cranks and connecting rods, g, the speed of the cranks being adjusted eo as to keep the slime in continual motion, and at the same time cause the ore to descend and deposit itself at the bottom, whilst the waste or lighter portion is carried towards the inner part of the machine, where it passes over a movable ring, h, which is raised mechanically, and in pro- portion as the ore rises in the apparatus. The waste is discharged through the outlet i, and conveyed away in launders. When the machine is filled with ore, it can be settled, as in the dolly machine, by means of percussive hammers, j j. The ore can be collected either by reversing the gear and lowering the ring H, or it may be washed into a receiver as con- venient. 502 Motion is given to the vertical bar k, which Is made to vibrate so as to turn by means of a ratchet the wheel i., fitted on a horizontal shaft, m. The ratchet is raised or lowered by a worm screw, in order to increase or decrease the speed rendered necessary by the qual- ity of ore operated upon. On the horizontal shaft m is a worm pinion, that works a wheel on a perpendicular shaft, N, on which is fixed a second worm pinion, raising or lowering the tooth segment on the end of the beam o. This segment ^an be shifted out of gear. The opposite end of the beam o is attached to the rod p, ami connected with the cross-bar r, as also with the ring h, which has a reciprocatory motion in the centre of the perpendicular shaft F. From the foregoing description it would appear that Mr. Borlase has combined in this apparatus the principles of the round buddle with that of the dolly tub. In the year 1857, Herr Von Sparre, of Eisleben, Prussia, patented four machines for separating substances of different specific gravities, in all of which water is employed, either ;is a medium throiigh which the said substances fiill under the action of gravity, or as an ai^'cnt for facilitating the motion of portions of the said'suljstances along inclined surfaces. The particulars, together with illustrations, will be found in patent No. 1405 for the year 1857. The mechanical preparation of tin and copper ores has from time to time been noticed by several writers. In 1758 Borlase described the method employed in the west of Corn- wall. Twenty years later. Price, in his Mincralogia, added to Borlase's description, and illustrated some of the apparatus then in use. Afterwards Dr. Boase published, in the second volume of the Ti-ansactiona of the GcoJorfiral Sociefi/ of Cornii'nll^ an article »ipon the dre.'^sing of tin in St. Just. In Vol. IV. Mr W. Jory Henwood inserted a paper on dressing ; and some general remarks will be found on the subject in De la Bechc's Report on the Geolocii/ of Cornwall. The enrichment of lead ores has been noticed by Forster, in his Section of Mineral Strata ; also by Warington W. Smyth, in his memoir On the 31ines of f'orflif/anxhi.rc, in the second volume of the Memoirs of the Geolor/ical Survey of Great Brilah'. ORES, DRESSING OF. 8GI In France, Dufrenoy and Elie de Beaumont, Coste, Perdonnet, and Moissenet, have treated on the mechanical enrichment of copper and tin ores. The latter gentleman visited this country in 1857, and subsequently gave the results of his observations in a highly in- teresting memoir, entitled Preparation du Mineral cCitain daiis le Cornwall. Too much attention cannot be given to this section of mining economics, for with the increasing pro- duction of ores, especially of ores of low produce, and the ill-adapted machinery oftentimes employed, the loss in concentrating them is an item of most serious moment, any reduction of which will be so much positive gain to the country. In this paper we have included those machines which have been long employed in our metalliferous mines — many of them having been proved by experience to be most econom- ical — together with such of the modern introductions as appear to promise the most advan- tage, and some suggestions which cannot but be valuable, since the principles involved are founded upon the universal laws of gravitating power, as applied to solids and fluids in motion. The Strake, Tye, and Strip. These appliances may be considered modifications of each other. Instead of effecting a separation by relying upon subsidence according to the specific gravity of the substances, they are mechanically impelled against a volume of water so regulated as to carry off the lighter particles. Fig. 503 represents a ground plan of a strake employed in the lead mines of Wales. 503 Its extreme length is about 18 feet, width 3 feet. The top increases from 18 inches to 2 feet 9 inches wide. It is constructed of wood, the bottom being covered with sheet-iron. The tye is usually 20 feet long, 2^ feet wide, and is often employed for cleaning hutch- work. In some instances when the ore or dradge is very rich, it is crushed and then tyed into heads, middles, and tails, the first portion going to pile, the middles re-tyed, and the tails treated as refuse or washed in the buddle. Fig. 504, A, inflow of water ; b, head of tye ; c, partition board. The stuff is intro- 505 ?^r^ duced into the cistern d, flows over the inclined front e, and is broomed at f. Between k and G are the heads, from g to ii middles, h to i, tails. At k is an outlet launder regulated with a flood shut. An outline plan of the tye is shown, fg. 505, The strip also consists of a wooden box with its bottom inclined at a greater or less angle, in order to suit the character of the stuff to be operated upon. The object of this appa- ratus is somewhat analogous to the separating l)Ox, viz., to deprive the ore of the fine parti- .cles with which it may be associated, and there- by to enrich it for subsequent treatment. A rather strong stream of water is emplovoii, against which the mixed mineral is violently projected by means of a shovel. When ores are strong and clean in their grain, but little loss can occur from this process, provided proper care be exercised in conducting it ; but if tlicir structure be delicate and the constitu- ents intimately mixed, the wastage must necessarily be groat. The ilhistration, ////. 506, shows a strip, cofer, and settling cistern, with filtering appa- ratus contrived for load ore. a, vertical launder C inches square, delivering water into the box D, 9 inches long by 26 inclies wide at the point c ; d, bottom of strip covered with 802 ORES, DRESSING OF. sheet-iron, 6 feet long and 16|- inches wide at e. At this point a ledge of wood is some- times introduced for the purpose of modifying the velocity of the water and forming a kind of shallow reservoir, so as to allow the workman to stir the stuff. At the end of the strip a cofer, f, is fixed, 1 1 inches deep, 30 inches square ; h, settling box, 6 feet long and 30 inches deep ; k, outlet for waste water. At G is inserted a filtering launder, 13 inches deep, extending across the cistern. At J a similar launder is placed, about 9 indies dee[i. The water comes in at a, is lodged in cistern b, flows smoothly over the feather-edged board c, falls into d ; here the orey matter is exposed to its action, a portion settles in f, the Jlorrin and other light waste then descends through g, depositing itself in the box n ; and to retain the valuable products as much as possible, it is filtered at j, through a perforated plate cov- ering the bottom of the launder. In stiipping, care must be taken to regulate the overflow of water at c ; rough stuff' must be subjected to a stronger current than finer matter, and the bottom of the strip should be constructed with a greater inclination. In some lead mines the buddle and hutch-work is stripped to be re-jigged, whilst the stuff resulting from the filtering box is hand-buddled until sufficiently enriched for the dolly. When ore is associated with a heavy matrix, and the grain breaks into a lesser size than the other par- ticles, the stripping may be performed by inversion, that is, to wash the orey product into the cover and filtering hutch, retaining the worthless portions at d. The flat buddle. Jig. 507, is a modification, peculiar to the Welsh mines, of the inclined plane, and different from all others in its 507 great proportional breadth, as well as its very trifling inclination. The stuff' is placed in a small heap on one side of the supply of water, and drawn with a hoe partly against and partly across the stream to the other side of the buddle, losing in its passage all the lighter parts. A heap of ore treated in this manner may be deprived of a portion of blende and pyrites, minerals which from their high specific gravity may have resisted previous opera- tions, a, platform of boards inclined two and a half inches in seven feet; b, catch-pit two feet deep. The width of this buddle varies from ten to twelve feet. Lisburnc Machiyic. — This apparatus was invented by the agents of the Lisburne Mines, Cardiganshire, and has been most successfully employed in separating blende from lead ores. F'kj. 508 represents an elevation, and fg. 509 a ground plan of this machine, b, rakes or ORES, DKESSING OF. 8G3 scrapers set at an ?injilc, depending from rods having their axis of motion on tlie arbor e. Tills arbor, as well as a parallel one, is carried on I'riction rollers o o', and so braced to- gether as to form a kind of frame, m, rod attached to frame, and connected with water- wheel L. N, balance-beam, counterpoising the frame, and rendered necessary in order to equahze the motion, p p', balance catches serving to support the third arbor when elevated. This arbor is also parallel to the other two, but has its position on the top of the guide frame shown in the elevation. It passes immediately under the angle of the L-shaped rods, and is mounted on friction wheels. Its action is as follows : — When the scrapers have nearly completed their ascending stroke, this arbor is elevated by means of the wedge- shaped projection on the top of the frame, and immediately the balance catch acts so as to retain it in this position during the descending stroke, at the termination of which the catch comes in contact with the projecting screw shown in the elevation, thereby dropping the scrapers upon the face of the buddle. Consequently, in the ascending stroke, these scrapers plough the vein stuff against the flow of the stream. The orey matter to be operated upon is introduced into the compartment shown on the top of the jjlan, and by means of the diagonal scrapers it is washed and passed slowly across the table, the heavier portion being delivered into the bin f, and the lighter matter into the box f', -whilst the tails are lodged in the strips ii ii. The water employed in driving the wheel is also used for the buddle ; one portion of it serves to introduce the ore, whilst the other is regularly diffused over the surface of the table, and washes the waste from the stuff. In case the quantity of water is too large for settling the residues flowing into the strips h h, and connected with the bins F f', discharge launders are provided at g. The table of the buddle has an inclination towards the bins f f', and catch-pits ii h. This machine makes about twelve strokes per minute, and may be furnished with any num- ber of rakes With twenty-two rakes, forty tons of stuff may be concentrated in ten hours, so as to afford ore for the deluing sieve, whilst the blende will be sufficiently cleaned for the market. The cost of this apparatus complete is about £30. Sand and Slime Dressing Machinery. In most mines a large proportion of the ore is composed of dradgc, and has to be brought to a fine state of subdivision either by the crushing-mill or stamps. In this condition the ore is freed from sterile matter, and rendered fit for metallurgic treatment. A variety of machines have been invented and applied to this division of dressing, in which the leading principle is to produce a separation by subsidence, according to the density of the sub- stances. In connection with this principle, the stuff is not permitted to have a vertical fall, but is traversed by a flow of water, on a table or bed set at such an angle to the horizontal plane as may be found expedient. With extremely fine stuff apparatus, including botii of these features, are sometimes subjected to a mechanical jar or vibration, so as to loosen and eject, as it were, the worthless matter with which it may be charged. In concentrating crushed or stamped ore, a certain quantity will often exist in a very miimte state of division, unable to withstand the currents and volume of water necessary for the separation of the larger particles. The amount and richness must necessarily depend upon the united produce and charac- ter of the ore, as well as the mode of treatment observed. A good dresser will form as little slime as possible, since when the ore is brought to this condition it is usually associated with a large mass of worthless matter ;. and not only so, but the expense of extracting it is materially increased. The loss under the most favorable manipulation is very large, whilst tlic machinery requisite is probably more complicated and expensive than any other section of the dressing plant. Although several machines are illustrated under this head, and many more might have been added, it does not follow that they may be advantageously employed for every variety of ore. Thus an apparatus which would enrich slimes by one operation from H to 5 per cent., might be both economical and desirable for treating copper ore, Imt would not be so impor- tant in the case of lead ore of the same tenure ; for after deducting the loss of metal inci- d'Mit to the enrichment, charging the manipulative cost on the full quantity of stuff, and estimating the rel.ative value of the two products, it might be found that one would scarcely leave a margin of gain, whilst the other would yield a satisfactory profit. The proper sizing of slime is as necessary as in the case of coarser work, and for this purpose Captain Isaac Richards, of the Devon Consols Sline, has arranged a peculiar slime- j)it. The water and stuff from the slime separated, are delivered through a launder into this pit, at the head of which is fixed a slightly inclined i)lank, divided itito chaimcls by slips of wood set in a radial direction from the aperture of the delivery launder. This pit has the form of an inverted cone, and since the water passes through it at a very slow rate, the more valuable and heavier matters will be deposited at the bottom. This apparatus thus becomes not only a slime-pit, but also a slime-dresser. The ordinary slime-pit has u.sually vertical sides and a flat bottom ; the slime and water enter it at one of its ends by a narrow channel, and leave from the other by the same means. 8(J-i OEES, DEESSING OF. A strong central current is thus produced through the pit, whicli not only carries with it a portion of valuable slime, but also produces eddies and counter-currents towards the sides which have the etibct of retaining matters which from their small density should have been rejected. The improved pit, Jig. 510, receives its slimes from the divided head b, and lets a por- tion of them off again at c, whilst the richer and heavier matters, which fall to the bottom of the arrangement, escape through the launder d, and are regulated by means of the plug A, and the regulating screw a'. At Devon Consols the slimes flowing from the launder d are directly passed over Brun- ton's machines, but instead of these sleeping tables may be employed. In many cases sand and slime stuff are much commingled with clay, and require to be broken and disintegrated before the ore can be extracted. A method for accomplishing this is shown in Jig. 511. a is the circumferential line of a round buddle ; B, launder lead- 511 /) #-NH^l^ ing to such buddle, or any other enriching apparatus ; c , sifting trommel ; d, rotating pad- dles ; E, tormentor ; f, driving shaft. A modification of this method is found in the slime trommel, fig. 512. a, hopper, into 612 ■/vvvvvvvvvvj;/ 7V777777777777 -r-.^A — 1.1 '^^-^-^l.,! ORES, DRESSING OF. 805 which slimes :ire lodged ; b, launder, delivering clean water into hopper a ; c, trommel of sheet-iron, fitted in the interior with spikes for the purpose of dividing the stuff; d, disc, perforated to prevent the passage of pieces of chips or bits of clay and stone ; e, Archime- dian pipes fitted into a disc of sheet-iron, conveying water into gauze or perforated trom- mel F ; G, slime cistern ; h, cistern for receiving the rough stuff; j, slime outlet, communi- cating with round huddle, or other suitable apparatus ; k, outlet for trommel raff, which may be delivered to a sizing cistern. The speed of the gauze trommel for fine slimes varies from 80 to 100 feet per minute. Hand Buddie. — This apparatus is somewhat extensively employed in lead mines for the concentratiou of stuff which contains but a small proportion of ore, such as middles and 513 tails resulting from the round buddle, or the tails from strips, &c. A rising column of water is shown at a. This flows into a trough b, and through peg-holes into c. Here the stuff' to be treated is introduced, and continually agitated by the boy in attendance. The finer por- tion passes through the perforated plate at d, and is distributed by the fan-shaped incline E in a uniform sheet on the head of the buddlef. A boy stands just below the higher line of middles with a light wooden rake ; with this instrument he continually directs the descend- ing current to the head of the buddle, and by this means succeeds in separating a larger proportion of the ore than would otherwise be done. Whether the rake or the broom be employed, it is found that some of the fine lead is jlorrined to the extreme tail of the buddle. In order to prevent this, the frame G has been introduced. It is strained with canvas, and always floats on the flooded water. This canvas retains the fine lead, w4iich is from time to time washed off in a cistern of water. The section to the first dotted line shows the heads of the buddle ; from this to the second dotted line will be the middles, and from the second dotted line the tails commence. It must, however, be remarked, that the exact line of heads, tails, and middles, must depend upon their relative richness. The wooden rake is undoubtedly preferable to the broom, as will appear from the following ex- periment made at the Swanpool Mines, every thing being equal in both trials. Stuff operated upon ; tails from washing strips assayed 13 per cent. With Broom. With ■Eake. No, 1. Heads, assayed - - - 167o - - - 20% 2. Middles, ditto - - - - 4f . . . sj 3. Tails, ditto - - - - 4J - - - 1^ It would be found a great improvement if these buddies were arranged so as to have their bottoms elevated when it'might be necessary. As they are fitted at present, the angle at tiie head is a constantly increasing one. The result is, the heads become poorer and the tails richer, provided the fixed inclination of the buddle is correct at starting, as the opera- tion proceeds. In proportion to the poorness of the stuff the buddle should have its width increased, as well as be made shallower. If the stuff be also passed through a trommel before entering the buddle, the result will be found much improved. The Round Buddie is said to have been first introduced into Cardiganshire, but has now become general in every important mining district. This machine serves to separate par- ticles of unequal specific gravity in a circular space inclined from the centre towards the cir- cumference. Its construction will be best understood by reference to the annexed engrav- ing, Ji(i. 514, in which a is the conical floor, fornKnl of wood, and about 18 feet in diameter, 'on which the stuff is distributed ; b is a cone supporting the upper part of the apparatus, and serving to effect the equal distribution of the orey matter, d is a wheel for giving mo- tion to the arrangement ; e, a funnel lunf'orated with four holes and furnished at top with an annular trough ; f f are arms carrying two brushes balanced by the weights G G ; H is a launder for conducting the stuff from the pit i ; k is a receptacle in which the slimes mixed with water arc worked up in suspension by the tormentor, which is a wooden cylinder pro- vided with a number of iron spikes ; l is a pulley taking its motion from a water-wheel, and Vol. III.— 55 866 ORES, DRESSING OF. M a circular sieve fixed on the arbor n. The stuff at K is gradually worked over a bridge forming one of the sides of a catch-pit between the sieve M and the tormentor, from whence 514 it passes off into the sieve, by which the finer particles are strained into the pit i, whilst the coarser, together with chips and other extraneous matters, are discharged on the inclined floor in connection with the launder o. From the pit i the stuff flows by the launder n into the funnel e, and after passing through the perforations flows over the surface of the fixed cone B, and from thence towards the circumference, leaving in its progress the heavier por- tions of its constituents, whilst the surface is constantly swept smooth by means of the re- volving brushes. By this means the particles of different densities will be found arranged in consecutive circles. The arms usually make from two and a half to four revolutions per minute, and a machine having a bed 18 feet in diameter will work up from 15 to 20 tons of stuff per day of ten hours. Oennan Rotating Bxddle. — This machine is said to effect the separation of the earthy matters from finely divided ores more readily than the ordinary round huddle. For this purpose the pulverized ore is introduced near the centre of a large slightly conical rotating table, and flowing down towards its periphery a portion of the upper part or head becomes at once freed from extraneous substances. Beyond this line of separation in the direction of the circumference, the stuff is subjected to the action of a series of brushes or rakes, and by means of a sheet of water flowing over the agitated slimes, clean ore is stated to be pro- duced almost at a single operation. The illustration, fff. 515, represents this machine as first erected at Clausthal, but it may 515 be remarked that some of its mechanical details have been since judiciously modified by Mr. Zenner of Newcastlc-on Tyne. a is an axis supporting and giving motion to the table c, 10 feet in diameter, and rising towards the centre 1 inch per foot; r, cast-iron wheel 15 inches in diameter, 0])crated on by the tangential screw n. The tooth-wliecl f drives flie pinion f, the axis of whicli is provided witli a crank giving motion to a rod fitted with brushes; o is an annular receiving-box 4^ indies wide, and 6 inches deep; a, circular trough of sheet-iron supported on the axis of the table an iiu-h or two above its surface, am! so divided that one quarter of it serves for the reception and equal distribution of the slime, whilst the other three-quarters supply clear water ; b, launder for supplying slime ore, lie- hind which is another not shown, for bringing in clear water. o, trough supplying addi- tional water to the stuff agitated by the bruslies. One end of this water-trough is fixed about the middle of the table, whilst the other advances in a curved direction nearly to the circumference. 77/e Concave Sli?ne Buddie. — The object of this apparatus is to concentrate on the periphery of the floor, instead of the centre. This arrangement gives an immense working ORES, DRESSING OF. 8G7 area for the heads, and at the same time admits of the separation of a greater portion of the waste than can be effected by tlie ordinary round buddle. After the slimy water has been discharged on the edge, the area over which it has to be distributed is gradually contract- 51G '¥£M/y' y^/!'///////^' ing, thereby increasing the velocity of the flow, and enabling it to sweep off a proportion- ate quantity of the lighter matter associated with the ore. a represents the inflow slime laimder ; 6, a separating trommel, through which the slimes pass previous to their entrance into the launder a. C, outlet launder, for taking off castaways ; ^, arbor giving motion to the buddle arms and diagonal distributing launders attached thereto held by the braces 10 w' ; e, bevel wheel on driving arbor; /", dowm-ight launder, to which is affixed a regu- lating cock. A', for supplying slimes to trommel ; /;, hiuiider for delivering clean water to circular box m, and which water passes through slot openings at ;> ;;, uniting with and lliin- ning the slimy matter previous to its passing into the diagonal delivery launders; /', circu- lar pit for receiving tailings. Attached to the wooden bar x is a piece of canvas with cor- responding pieces depending in a similar manner from each arm, and which serve to give an even surface to the stuff in their rotation. The slimes flow from four diagonal launders, each having its upper end in communication with box /. The speed of the arms anniployed, not 878 ORES, DRESSING OF. 533 only to concentrate the viscid kind of slime sometimes found at the periphery of the round huddle, but also to dress the tops and middles resulting from the dollying operation. The small water-wheel, shown in fg. 532, is sufficient to drive six of these machines, viz., three on each side. Before the stuff is permitted to enter upon the rotating cloth, it is disintegrated by tormentors, and passed through a sizing trommel ; it then flows over the head or dispersing board l, on to the cloth. This cloth rotates towards the stream on two axles, H and m, and is supported by a third roller n. It is also stiffened in its width by nu- merous laths of wood. Clean water is introduced behind the entrance of the slime, in order to give it the proper consistency. Different degrees of inclination are given to the cloth by raising or lowering the roller m, by means of the screw k. The heavier particles lodged on the cloth are caught in the wagon r, whilst the lighter matter is floated over the roller m. The following particulars are furnished by Captain Isaac Richards, of Devon Great Consols: — One revolution of the cloth is made in 4|- minutes ; its length is about 29^ feet, so that it travels say G4- feet per minute. Its width is four feet two inches. Before the slime comes upon the cloth it is reduced to a size of '/eo of an inch, and yields an average of li of copper ; but by means of this machine the stuff is concentrated so as to afford 5 per cent. In ten hours it will clean 1| tons, at a cost of Is. per ton. The speed of the cloth must, however, be varied with the condition of the stuff; if it be very poor, the cloth must travel verj much slower, since the enrichment requires a longer period of time. At the end of the machine, and worked by the same water-wheel, is a dolly tub ; but the mode of working this apparatus is fully stated on the next page. Bradford's Slime Apparafus, fg. 633, has been extensively employed at the Bristol Mines, situated in Connecticut, United States. Its action is intended to imitate that of the vanning shovel. The slime enters by the launder A, about 5 inches wide, and descends on the in- clined head a', which expands from the width of the launder to within a few inches of the width of the table frame b. The slime box a" is per- forated at D with numeroiLS holes, each of which is fitted with small regulating pins. The table b b is 2 feet 2 inches wide, and 2 feet 10 inches long, with a bottom formed of cop- per gauze. It is suspended by the vertical rods ^ K K, and varying degrees of inclination are given to the table by altering the levers h ii. For the purpose of quickening or decreasing the action of the table, two cones are employed, l l', upon which the driving band is shifted as may be neces- sary. A band f^i-om a runner, fitted on the axis of the cone i., communicates motion to a pulley- wheel, M, upon the shaft of which are cranks attached to connecting rods G, giving motion to the table. When the machine is in operation, the ore flows over at f, into the launder beneath it, whilst the waste is carried over the opposite end into the trough e. Prof. B. Silliman, Jr., and Mr. J. D. "Whitney, give the following particulars of results realized by this machine : — The total weight of ore stuff pressed during 122 days was 11,948,900 pounds of rock stamped and crushed, or 5,080 tons miners' weight. The total ore sold from this quantity of stuff was 128 gross tons, (2,352 lbs.) or 2''Vino per cent, of the stuff worked over. By the Captain's vans tlie average richness of the stamp work (forming much the larger part of what goes to the separa- tors) for 22 weeks was 2*32 per cent. The humid assay of the average work from the stamps for five weeks in July and August, gave for the rich- ness of the stuff dressed on the separators 3'28 per cent, of ore, or -984 per cent, of metallic copper. There is, therefore, an apparent loss in the tailings of "/loo per cent, of 30 per cent, ore, or '^Vioo of copper. The amount of ORES, DRESSING OF. 879 ore, however, lost in the tailings does not exceed */io to 7io per cent., or about "/loo per cent, of copper. The actual products of working, therefore, as may be seen, exceed for the machines the average richness of the Captain's vans. Of the total ore produced in this time, 181,126 pounds came from the separators, and 160,858 pounds from the jiggers. The whole amount of stuff, therefore, required to pro- duce this amount of ore, estimated from the above ratio (1.15 : 1) is 768,680 pounds. This may be taken approximately as the actual quantity which passed over the separators, and if calculated on the Captain's vans, it should have produced 177,061 pounds of ore, while in fact it did produce 181,126 pounds, or a variation in excess for the machines of only 3,210 pounds. Each of the separators, therefore, dresses about 1^ tons of rock daily, of stuff yielding an average of 2'5 per cent, of 30 per cent. ore. Dolly Tub or Packing -Keeve. — This apparatus is employed for the purpose of excluding fine refuse from slime ore, which has been rendered nearly pure by previous mechanical treatment. In using it the workmen proceed thus : — The keeve,^5r. 534, is filled to a cer- tain height with water, and the dolly a introduced. A couple of men then take hold of the handle b, and turning it rapidly cause the water to assume a circular motion. The tossing is then commenced by shovelling in the slime until the water is rendered somewhat thick. After continuing the stirring for a short period, the hasps e e are loosened, and the bar d with the dolly suddenly withdrawn. The tub is then packed by striking its outside with heavy wooden mallets. When this operation is terminated, the water is poured off through plug-holes in the side of the tub. The object of the rotary motion created by the dolly is to scour off clayey or other matter ad- hering to the ore, whilst the packing hastens the subsidence of the denser portions. In one opera- tion of this kind four distinct strata may be pro- cured, as indicated by the lines a b, c d, cf, g /;, c Z.-, iuyfr/. 535. The upper portion, viz. from a to b, will prob- ably have to be set aside for further washing, whilst the schlich c should be fit for market. The conical nucleus in the centre of the tub generally consists of coarse sand, and is usually further enriched on a copper bottom sieve, or else submitted to the action of a tye, or other suitable apparatus. ILtcfiine Dollg Tub. — This keeve is packed by machinery represented in the accompanying 584 880 ORES, DRESSING OF. woodcut, {fg- 53fi,) in which a is a small water-wheel working a vertical shaft b, and drivin" another o. At the bottom of this is fixed a notched wheel d, which presses outwardly the hammers K E ; these are mounted upon iron bars F f', and violently driven upon the side of the keeve by means of springs g g'. The degree to which ore can be concentrated by dollying must evidently depend upon several conditions: — 1st. The initial percentage of the ore. 2d. The condition to which it is reduced. 3d. The matrix with which it is associated. 4th. The proportion of water em- ployed. And lastly, if the rotation and packing have been judiciously performed. An experiment upon some sandschlich lead ore, much intermixed with fine carbonate of iron, gave the following results: — Introduced into dolly tub, 17 cwt., assayed, 487o Time required to introduce stuff .... Dolly rotated ....... Dolly withdrawn — Tub packed Running off water Skimming and cleaning out tub .... Top skimmings - Second " Clean ore, middles " bottom 4 cwt, assayed Total 6 minutes 5 11 5 u 6 11 20 tt 42 - 20Vc - 45 . 65 - 6VJ Fine schlich Total - 11 It may be remarked, that none of the various processes of dressing is more satisfactory than that of dollying, since, if carefully conducted, little or no loss of the total quantity of ore can occur. Jordan's System of coxTiNUors Dressing. "We have now to notice a method of separating mineral sands of varying specific gravity, which was first used by Mr. T. B. Jordan at the Colonial Gold Works, in separating gold from quartz and other gangues with which it was associated. The plan was successfully practised for its original object during the years 1853 and 1854, and lias since been elabo- rated for general application to dressing minerals. The principle on which the system is founded, is the fact that bodies having the same bulk and various gravities, will fall through a column of water in the order of their densi- ties, and hence that water moving upwards, at a rate greater than that at which any given body would descend through still water, will not allow such a body to descend through it, but will carry it up, and deliver it over the top of the containing vessel ; therefore, granting that it is possible to reduce metalliferous ores to grains of uniform bulk, and taking the most simple case for our illustration, such as galena and carbonate of lime, or quartz, it becomes at once obvious that an upward stream of water may be so regulated as to throw over all the lime or quartz, and allow all the galena to pass through it ; but as we seldom find the associated material so simple, and as there is considerable difficulty in reducing minerals to grains of absolute identity of bulk, we must be content to complicate our ma- chinery a little, and to put up with a somewhat less perfect or more laljorious result than this argument seems to promise ; nevertheless the author of this system contends, that the introduction of tliis clement of was/ting by the np current, greatly facilitates the arrange- ment of dressing machinei-y of continuous action ; and, further, that if perfectly continuous action can be secured, so that each machine shall deliver its products to the next in succes- sion which is to be employed on them, a very great improvement will have been effected, and a great saving made on the present cost of dressing ; for it would not be difficult to show that nine-tenths of the labor consist of putting down, picking up, and transferring the matefial to the various processes through which it passes. Our figure (537) must be taken as a diagram illustrative of Mr. Jordan's views. In actual practice, the construction is varied to meet the peculiarities of each case, while the general principle here illustrated is strictly adhered to. a is a tram bringing the rough material to the crushing rollers d ; c c is a sort of raff wheel so arranged as not only to serve the usual purpose of returning the stuff not sufficiently crushed to the rollers, but also to separate that which is crushed into four or more sizes by the concentric rings of wire-work which divide the wheel into the compartments 6, 8, 10, 12. These numbers may be taken to denote tlie mesh in holes per lineal inch, and if so, all the materials from the crushing rolls being con- veyed into the centre opening of the wheel will be sharply rolled over a six-hole sieve of OEES, DRESSING OF. 881 great area ; that part of it which is fine enough will pass through the mesh, that which is not will be carried up by the partition or bucket which returns it to the mill for further grinding. In the stuff whicla has passed the ti-hole sieve, and reached the compartment marked 6, there will be a large proportion which will pass the next or 8-hole sieve, and again from the 8 to the 10 and 12, so that this wheel separates the ground stuff into four lots of approxi- mately uniform grain. To secure the greatest effect from this separator, the stuff must be either perfectly dry, or ground with a good stream of water passing between the rolls and through the wheel. Each compartment of the wheel is furnished with one stop-bucket and spout which, when it arrives at the top, delivers the contents of the compartment collected during the revolution into separate launders which carry it to as many different tubes, one of which is shown at d. These tubes are supplied with water from a main p, which is in connection with a reservoir some 12 or 14 feet above the level of the dressing floor; a few inches above the true bottom of the vessel n, there is a false bottom or diaphragm of wire- gauze, through which the water rises. Under the conditions described, the superintendent will have the power of regulating exactly the quantity of water which shall rise through each tube in a given time, and therefore the rate of the upward flow of the water ; or, in other words, he will be able so to adjust each stream as to throw over the waste, and allow the valuable part of each sand to fall on the wire bottom of its tube. It is of course admit- ted that the sizing effected in the wheel c, although better than by the usual methods, is still but an approximation to perfect sizing ; and even if in the wheel it were perfect, still the rush through the launders would inevitably produce some dust ore if dry, or slime ore if wet, so that it would not do to throw away ail that is washed over the top of the tubes; it therefore passes forward to the hutch e, where it falls on a fine gauze bottom sieve, parted longitudinally into as many divisions as there are tubes or sizes of sand to be worked ; the bottom of each of these divisions is composed of a wire gauze, somewhat finer than that of the compartment of the parting wheel from which the sand came, and therefore none of the waste can find its way into the hutch ; the action of this sieve is widely different from that of a jigging machine, inasmuch as the back and fore part of it have a different kind of mo- tion, and it is a machine of continuous action, not requiring the constant attention of skilled labor. The crank G, by its constant rotation, dips the back of the sieve a few inches under water, and at the same time draws it back through the water at every revolution, and on rising and passing over the upper half of its revolution, it frees the sieve forward, while all its contents are above the surface of the water in the hutch. The front of the sieve is sus- .pended by a pendulous rod from the point n, so that it has very little elevation and depres- sion, while it has the same lateral motion as the back, and this enables the sim|)le hanging scraper, which can move freely outwards but cannot pass inwards beyond the perpendicular, to throw over a portion of the waste at every stroke, this I)eing much assisted by the stream constantly flowing over it. There are cleats placed acro.ss the bottom of these sieves both above and below, the tendency of which in giving direction to the waste, and stopping the rich slimes, will be readily understood on reference to the figure. The dolly tub K is Vol. III.— 56 882 ORES, DRESSING OF intended to meet the case of secondary products, such as "Jack," or other ore of zinc, fre- quently associated with lead. Tiie peculiarities of its construction are such as are requisite to avoid the necessity for stopping and takiiifi the machine apart in order to dig out its contents ; it is accomplished partly by the direction given to the revolving arms which tend to lift the stuff, but prmcipally by an up current of water of sufficient rate to throw over the lit^htest of the two materials now associated ; as in the former case the original sizing is not abandoned, but a separate dolly tub is used for each size, so that the up current may still be adjusted to its work with the greatest precision ; the step or bearing in the bottom of the tub is protected from the sand by a sheet-iron cone attached to the shaft, into which the clean water from the main is supplied, so that the stream of water constantly running from under the edges of this cone, keeps the step at all times perfectly clean and free from sand ; p is the main for supplying to the tub, and there is a tap on the communicating pipe which regulates its forces m is the waste wagon, having a riddled bottom for drawing off the wa- ter; is the "Jack" wagon into which the clean stuff from the tub is occasionally dis- charged by the sluice valve ; and n is the lead wagon for carrying awa'y the clean ore from the tubes ; this wagon, like the others, is furnished with a riddled bottom covered with some material which is too fine in the mesh to allow any of the ore to pass ; the oie is drawn off from the washing tubs from time to time in small quantities ; each wagon remains under its own tube until it has received a full load, and is then wheeled off to the ore house; by this system, the inventor says, nothing is left to clean up but the hutch f, and its sieve, which latter may require looking to two or three times a day, and the bottom of hutch about once in three days. Vcauiing is a method commonly practised by the dressers of Cornwall and Devonshire, by which they ascertain approximately the richness and properties of the ore to be treated. If the object be to determine the value of a pile of stuff, it is carefully divided, then sampled, and a portion, say a couple of ounces, given to the vanner. If the stuff thus given should be rough, it is reduced to the tenure of fine sand, and in this state put upon the vanning shovel. The operator now resorts to a cistern or stream of water, and bj frequently dip- ping the shovel into it, and imparting to the shovel when withdrawn a kind of irregular cir- cular motion, he succeeds in getting rid of a greater or less portion of the waste : that which remains on the shovel is then considered equal to dressed work and assayed. So accurately is this operation performed bv many of the tinners, that parcels containuig only fifteen pounds of tin ore per ton of stuff, are sold by it to the mutual satisfaction of both buyer and seller. The vanning process is also well adapted for determining the properties of an ore. If, by this method, vein stuff should withstand concentration, no machinery is likely to dress it. If also the loss of ore is found great, then the apparatus to be employed for effecting the enrichment will have to be carefully considered and constructed. Fig. 538. The vanning shovel a is 14 inches long, and 13 inches wide at the top, the edge of which is slightly turned up. The shovel is also formed with a hollow or depression. The handle is about 4 feet long. The vanning cistern is shown at b. Hushing. — It often occuis, that the water employed on the dressing floors makes its escape below the refuse or waste heaps. This may be used for the purpose of hushing, which operation is performed in the following manner: — The husher diverts the escape water into a rivulet and introduces a given quantity of waste. He then builds a dam or reservoir, with a door or traj) valve at the high end, in order to collect the necessary water for hushing, and puts aside all the large stones lying in the middle of the hush gutter in order to form them into a wall. After this, he starts his hush by lifting the door of the dam, which slides in a wooden frame adapted for that purpose. ORES, DRESSING OE. 883 This allows the water to rush out, aud displaces the waste to a certain depth, at the same time driving it forward. If the husli has bared or uncovered a further quantity of large stones in the middle of the gutter, they are again removed to one side, since they would retard the force and action of the water. When these impediments are removed, the water is repeatedly discharged from the reservoir until the waste is hushed off the ore, which Ls found lying in holes, and around earth and fiist stones, in the bed of the rivulet. A clay bottom is found to be most favorable for hushing, and the velocity and power of the stream should be proportioned to the size and density of the waste to be treated. Forwarding and Lifting Apparatus. Besides the machinery required for the enrichment of ores, it is a matter of great im- portance to introduce such auxiliary arrangements as shall not only facilitate actual dressing, but also be in themselves somewhat inexpensive. In this division, as in every other, the means should be strictly adapted to the end, and ought not to bear a cost disproportionate either to the circumstances or prospective advantages of an undertaking. The shovel,/^. 539, usually employed in British mines, is of triangular shape, and made of good hammered iron pointed with steel. The dimensions vary, but one of an average size is about II inches wide at the top, and 13 inches from the point to the shank, weight 4 pounds, and costs one shilling; to which must be added, five pence for the hilt, or handle. The hilt should be of ash, free from knots and slightly curved. 539 510 Picking Boxen, fig. 540, are employed for the purpose of collecting the prill and dradge ore from the stuff with which it may be mechanically intermixed. These boxes, or trays, are handled by children. They are made of deal, 1 inch thick, of the following dimensions : Length, 16 inches; depth, 7 inches; width at bottom, 7 inches; width at top, 10 inches; and cost about Is. Zd. each. A ledge of wood to serve as a handle is sometimes nailed to the ends of the box. Wheelbarrow. — The sides, ends, and bottom are composed of deal 1^ inches thick. The ends are mortised to the sides, whilst the bottom is generally fostened by means of nails, and bound with slips of hoop iron at the angles. Hoop iron is also employed to protect the upper edges of the barrow. The wheel is often made of wrought iron, (f round,) and 14 inches diameter. Its axes rotate in wrought-iron ears. The extreme length of the sides of a well-proportioned barrow is 60 inches, depth at centre 9 inches ; the ends are inclined, as shown in fig. 541. The cost of a barrow with wrought-iron wheels complete will vary from 6s. I6d. to 7s. 541 542 513 Hftndbarrow. — When large quantities of stuff have to be removed from place to place on the surface, and where it would be inconvenient to use the wheelbarrow, a barrow having handles at both ends is employed. It is made of deal plank 1;^ inches thick ; the length of the sides is 5 feet 6 inches ; depth in centre, 9 inches ; width, 18 inches at top and 10 inches at bottom; length, 24 inches at top and 18 inches at bottom- cost complete, about 4s. &d. Railroads. — The gauge of surface roads varies from 2* feet 4 to 2 feet 6 inches within the rails. Instead of manufactured rails, common flat wrought-iron, 24 inches wide and ^ inch thick, is oftentimes employed. An ex- tremely serviceable rail is formed of a strip of timber 2 inches square, upon which is laid wrought-iron, l^- inches wide and J inch thick, fastened by means of nails or screws. Tram \V(tgon and Turn Tabic. — A good tram wagon and turn table are sliown, /fr/. 54:^. The wagon is built of wrought-iron, with cast-iron wheels. The latter are usually 12 inches diameter, with flanges 1 inch deep and tires from 2 to 3 inches wide. The turn fable is of cast-iron. 8S4: ORES, DRESSING OF. It does not rotate, but the wagon is easily directed to either line of rail by means of the cir- cular ring ; the elliptical loops in advance serving to guide and place the wheels on the rails. Lifting Apparatus. — It sometimes happens that the surface is nearly level, and affords very little natural fall. In such case the enrichment of ores becomes more expensive from the necessity of shifting some of the various products by manual labor, and of introducing lifting appliances in order to procure the requisite elevations for carrying out the various elaborative processes. It is, moreover, scarcely practicable from the conformation of the ground to form useful reservoirs of water within a reasonable distance ; neither does it com- monly occur in such cases that a free supply can be obtained for washing. The pumping engine is therefore required to furnish the requisite quantity of water. This is generally conveyed over the floors by wood launders, often interfering with each other and obstructing the direct circulation of carts, railways, &c. Now if a stand-pipe or pressure column were erected at the engine, and a main judiciously laid throughout the floors, it is obvious that it would not only remedy this evil, but also afford water for the several washing purposes, as well as motive power for common, dash, or other wheels, together with turbines, flap jacks, &c. When an inconsiderable proportion of water has only to be raised to a higher level, the common shoe or chain-pump will be found to render effective service ; but when a larger stream is requisite, it would be better to employ the rotary pump. This pump, Jiff. 544, has been brought to great per- fection by Messrs. Gwj-nne ; a is the suction-pipe, and b the discharge, the dotted lines showing the discharge B, horizontal when required. Pumps of the following dimensions are stated to raise and discharge per minute for medium lifts, say from 10 to 10 feet high: — Diameter of Diameter of Gallons of discbargc-pipe. suction-pipe. water per minute. 1^ inches. 2 inches. 25 E '70 150 300 500 1400 Stuff consisting of slimes and sand may be readily elevated by means of a Jacob's lad- der or the Archimedean screw. For short elevations combined water and raff wheels devis- ed by Mr. Charles Remfry of Stolberg, Prussia, may be advantageously employed. Fig. 645, a, water-wheel ; b, raff or inverted wheel ; c, axis of both raff and water- 645 ^pl^^^^^^^^^^l , wheels, carrying a tooth-driving wheel; n, sizing trommel; e, launder for inlet of stuff; f, discharge launder; G, shoot .delivering water and raff to launder ii ; e, cistern receiving slime from trommel. Slime Pits. — In the several operations of cleansing ores from mud, in grinding, and washing, where a stream of water is used, it is impossible to prevent some of the finely attenuated portions floating in the water from being carried off with it. Slime pits or OXIDES. 685 labyrinlhx, called huddle holes in Derbyshire, are employed to collect that matter, by receiv- ing the water to settle at a little distance from the place of agitation, These basins or reservoirs are of various dimensions, and from 24 to 40 inches deep. Here the suspended ore is deposited, and nothing but clear water is allowed to escape. The workmen employed in the mechanical preparation of the ores are paid, in Cumber- land, by the piece, and not by day's wages. A certain quantity of crude ore is delivered to them, and their work is valued by the bing, a measure containing 14 cwt. of ore ready for smelting. The price varies according to the richness of the ore. Certain qualities are washed at the rate of 2?. GJ., or 3.s-. the bing ; while others are worth at least lO.s. The richness of the ore varies from 2 to 20 bings of galena per sJdft of ore ; the shift corre- sponding to S wagon loads. It is not essential to describe the dressing routine observable in any particular mine, since it is scarcely possible to observe the same system in any two distinct concerns. In the various modes of treatment, however, it may be remarked that the two leading features will always be reduction to a proper size and separation of the ore from the refuse. Until the vein stuff arrives at the crusher or stamps, the labor is chiefly one of picking and selecting, but from these machines usualh' commence a long series of divisions, subdivisions, selections, and rejections. To follow these out in their various ramifications would not only exceed the limits of this paper, but would perhaps be misunderstood by those not intimatelv acquainted with the subject. — J. D. OTTO, OTTAR, or ATTAR OF ROSES. Otto of roses consists of two volatile oils ; one solid and the other liquid at ordinary temperatures, in the proportion of about one of the former to two of the latter. To separate them, the otto must be frozen and compressed between folds of blotting paper, which absorb the liquid, and leave the solid oil. They may also be separated by alcohol, (of sp. gr. -8,) which dissolves the liquid and scarcely any of the solid oil. The solid oil, according to Saussure, contains only carbon and hydrogen, and these in equal number of atoms, and is therefore isomeric with oil of turpentine ; it occurs in cry.stalline plates, fusible at 95^ F. The liquid oil has not been carefully ex- amined ; it is uncertain whether it contains nitrogen, or only carbon, hydrogen, and oxygen. Otto of roses is sometimes adulterated with some essential or fixed oils and spermaceti. The purity of the otto is determined by the following test : put a drop or two of the oil to bo tested in a watch-glass, and then add as many drops of concentrated sulphuric acid as of the oil ; mix with a glass rod. All the oils are rendered more or less dark-colored by this process, while the otto of roses retains its purity of color ; the oil of geranium if present acquires a strong disagreeable odor, which is very characteristic. — H. K. B. OXIDES are compounds containing oxygen in definite proportions. They are usually divided into basic oxides, which unite with acids ; acid oxides, which neutralize basic oxides, combining with them ; and neutral oxides, which do not unite with either bases or acids. In addition to these are saline oxides, or compounds which are pro- duced by the union of two oxides of the same metal. OXIDES for polishing. Oxides of Iron. — The finest crocus and rouge are thus prepared. Crystals of sulphate of iron are taken from the pans in which they have crystallized, and are put at once into crucibles, or cast-iron pots, and exposed to a high temperature ; the greatest care being taken to avoid the presence of dust. The least calcined portions are of a scarlet color, and form the jeweller's rouge for polishing gold or silver articles. The more calcined portions are of a purple or bluish purple color, and these form crocus for polishing brass or steel. It is found that the blue particles, which are those which have been exposed to the greatest heat, are the hardest. It will, of course, be understood that the result of the action of heat is to drive off the sulphuric acid from the protoxide of iron, which becomes peroxidized in the process. Lord Rosse, in the Philosophical Transactions, thus describes his process of preparing his polishing powder: — " I prepare the peroxide of iron by precipitation with water of ammonia, from a pure dilute solution of sulphate of iron. The precipitate is washed, pressed in a screw-press till nearly dry, and exposed to a heat, which in tlie dark appears a dull low red. Tlie only points of importance are, that the sulphate of iron should l)e pure — and the water of am- monia should be decidedly in excess, and that the heat should not exceed that I have described. The color will be a bright crimson, inclining to yellow. I have tried both pot- ash and soda pure, instead of water of ammonia, t)ut after washing with some degree of care, a trace of the alkali still remained, and the peroxide was of an ochrey color, and did not polish properly." Jeweller's rouge is, however, frequently prepared in London by precipitating sulphate of iron with potash, well working the yellow oxide, and calcining it until it acquires a scail 't color. Crocus is sometimes prepared after the manner recommended by Mr. Heath. Chloride of sodium and sulphate of iron are well mixed in a mortar; the mixture is then put into a s'i:t three-fourths of the known terraqueous globe. Water contains eight-ninths of its wjight of oxygen ; and the solid crust of our globe probably consists of at least one-third l)irt by weight of this principle ; for silica, carbonate of lime, and alumina, — the three most abundant constituents of the earth's strata, — contain each about one-half their weight of oxygen. Oxygen also constitutes about twenty per cent, by volume, or about twenty-three per cent, by weight, of the atmosphere ; and it is an essential constituent of all living beings, i'lints, in the sunlight, absorb carbonic acid, decompose it — keeping the carbon and ii;j;;rating the oxj'gen ; while animals, on the other hand, absorb oxygen and give off car- lijuic acid. Oxygen is :ei^ /^: l;li PAPER, MANUFACTUEE OF. 895 consiJerablo difference will frequently be found in the tint of the paper when the two sides are compared, in consequence of the coloring matter sinking to the lower side, by the natu- ral subsidence of the water, or from the action of the suction boxes ; and to obviate this, instead of employing the ordinary couch roll, which acts upon the tcpper surface of the paper, a hollow one is substituted, having a suction box within it, acted upon by an air Ijuraj), wliich tends in some measure to counteract the effect, justly considered ol)jection- able. Merging from those rollers the paper is received from the wire gauze by a continu- ous felt s, which conducts it through two pair of pressing rollers, and afterwards to the drying cylinders. After passing through the first pair of rollers the paper is carried along the felt for some distance, and then turned over, in order to receive a corresponding pres- sure on the other side, thus obviating the iuequality of surface which would otherwise be apparent, especially if the paper were to be employed for books. The advantage gaiued by the use of so great a length of felt, is simply that it becomes less necessary to stop the machine for the purpo.se of washing it, than would be the ca.se if the felt were limited in length to its absolute necessity. In some instances, when the paper being made is sized in the pulp with such an ingredient as j-es-j/j, the felt becomes so completely clogged in the space of a few hours, that unless a very great and apparently unnecessary length of felt be employed, a considerable waste of time is constantly incurred in washing or changing the felt. The operation of the manufacture will now be apparent. The pulp flowing from the reservoir into the lifter, and thence tlu'ough the strainer, passes over a small lip to the continuous wire, being there partially compacted by the shaking, motion, more thoroughly so on its passage over the air boxes, receiving any desired nuirks by means of the dandy roller passing over the continuous felt between the first pressing rollers, then turned over to receive a corresponding pressure on the other side, and from thence off to the drying cylinders, which are heated more or less by injected steam ; the cylinder which receives the paper first, being heated less than the second, the second than the third, and so on ; the paper after passing over those cylinders, being finally wound upon a reel, as shown, unless it Ije printing paper, which can be sized sufficiently in the pulp, by an admixture of alum, soda, and resin, or the like : in which case it may be at once conducted to the cutting machine, to be divided into auy length and width required. But, supposing it to be intend- ed for writing purposes, it has first to undergo a more efl'ectual method of sizing, as shown in t!ic accompanying drawing ; the size in this instance being made from parings olitained ftom tanners, curriers, and parchment-makers, as employed in the case of hand-made papers. Of course, sizing in the pulp or in the engine offers many advantages; but as g'jlatiue, or animal size, which is really essential for all good writing (lualities, cannot at [iresent be employed during the process of manufacturing by the machine without injury to the felts, it becomes necessaiy to pass the web of paper, after it has been dried by the cylinders, through this apparatus. In most cases, however, the paper is at once guided as it issues from the machine, through the tub of size, and is thence carried over the skeleton drums .shown, inside each of which are a number of fans rapidly revolving ; sometimes there are forty or fifty of these drums in succession, the whole confined in a chamber heated by steam. A pa[)er-machine with the sizing apparatus attached, sometimes measures, from the wire-cloth where the pulp first flows on, to the cutting machine at the extremity, no less than one thousand feet. The advantage of drying the paper in this manner over so many of these drums is, that it turns out much harder and stronger, than if dried more rapidly over heated cylinders. .'y the arrows, has simply an alternating motion, which serves to gather the paper in stich lengths as may be required ; the craidv arm c, which is capable of any adjustment either at top or bottom, regulating the extent of the movement backwards and forwards, and thus the length of the sheet. As soon as the paper to be cut off has passed below the point d, at which a prfsser is suspended, having an alternating motion given to it, in order to make it approach to and recede fiom a stationary presser-board, it is taken hold of as it descends from the drum, and the length pendent from the presser, is instantly cut off by the movable knife' E to which motion is given by the crank f, the connecting rod g, the lever ir, and the connect- ing rod I. The combined motion of these rods and levers admits of the movable knife e, remaining nearly quiescent for a given time, and then speedily closing upon the fixed knife K, cutting o(f the paper in a similar manner to a pair of shears, when it immediately slides down a board, or in some instances is carried along a revolving felt, at the extremity of which several men or boys are placed to receive the sheets, according to the number into which the width of the web is divided. As soon as the pressers are closed for a length of paper to be cut off, the motion of the gatheiing drum is reversed, smoothing out the paper upon its surface, which is now held between the pressers ; the tension roll l taking up the slack in the paper as it accumulates, or rather bearing it gently down, until the movement of the drum is again reversed to Annish another length. The handle m is employed merely (o stop a portion of the machinery, should the water-mark not fall exactly in the centre of the sheet, when by this means it can be momentarily adjusted. The paper being thus made, and cut up into sheets of stated dimensions, is next looked over and counted out into quires of 24 sheets, and afterwards into reams of 20 quires; which subsequently are carefully weighed, previously to their being sent into the market. Connected with the manufacture of paper, there is one point of considerable interest and importance, and that is, what is commonly, but erroneously, termed the water-mark, wliich may be noticed in the T'i/Hr.s- newspaper, in the Bank of England Notes, Cheques, and Bills, as also in every Postage and Receipt Label of the present day. The curious, and in some instances absurd terms, which now puzzle us so much in de- scribing the different sorts .and sizes of paper, may frequently be explained by reference to the various paper marks which have been adopted at different periods. In ancient times, when comparatively few people could read, pictures of every kind were much in use where writing would now be employed. Every shop, for instance, had its sign, as well as every public-house, and those signs were not then, as they often are now, only painted upon a board, but were invariably actual models of the thing which the sign expressed — as we still occasionally see some such sign as a bee-hive, a tea-canister, or a doll, and the like. For tiie same reason pi-inters employed some device, which they put upon the title-pages and at the end of their books, and paper-makers also introduced marks, by way of distinguishing the paper of their manufacture from that of others ; which marks becoming conuuon, naturally gave their names to difl'erent sorts of paper. And since names often remain long after the origin of them is forgotten and circumstances are changed, it is not surprising to find the old names still in use, though in some cases they are not applied to the same things which they originally denoted. One of the illustrations of ancient water-marks given in the ac- companying plate, that of an open hand with a star at the top, which was in use as early as 1530, i^robably gave the name to what is called fiaad paper, /.r/. 550. Another very favorite paper-mark, at a subsequent period 1540-GO, was the jug or pot which is also shown, /iV/. 551, and would appear to have originated the term pot paper. The foolscap was a later device, and does not appear to have been nearly of such long continuance as the former, ^'^. 552. It has given place to the figure of Britannia, or that of a lion rampant, supporting the cap of liberty on a pole. The name, however, has con- tiiaied, and we still denominate paper of a jiarticular size by the title oi' foohcap. The original figure has the cap and bells, of which we so often read in old plays and histories, as the particular head-dress of the fool, who at one time formed part of every great man's establishment. The water-maik of a cap may sometimes be met with of a much simpler form than thatjust mentioned — frer|ucntly resembling the jockey caps of the present day, with a trilling orna- mentation or addition to tiie upper part. The first edition of " Shaks[)eare," jjrintcd by laac Jar/f/ard 8 0-181 0-404 or as Sulphate of ammonia 1-037 0-702 1-567 Acetic acid 0-191 0-070 0-286 or as Acetate of Lime 0-280 0-111 0-419 l^vroxvlic spirit 0-14G 0-092 0-197 Viilalile oils - 0-790 0-571 1-262 F'x.'ddils 0-.5.'')0 0-266 0-760 l':naliine 0-134 0-024 0-196 908 PEAT A^'D TURF. It is- flius soon tliat the proportions of tliosc products vary within wide limits, wLich arc dctcrnjiiR'd In diHciuiicLv-; ()l'(|u:dity of the turl' or temperature in the distilliuiun. Several trials were made to determine the amount oi" Urcosote present in the tar, but glthough its presence could he recognized, its proportion was so minute as to render its (juautitativc estimation in)possihle. This circumstance constitutes an essential distinction ot peat-tar from wood-tar, and indicates i'or the former an infeiior commercial v;duc, as the presence of kreosotc, now so extensively employed, is an clement m the estunato of the price of the tar obtained i)y distilling wood. " It will be understood," writes Sir Robert Kano, " that the materials indicated in the foregoing table by the names 'fixed and volatile oils' are in reality mixtures of a variety of chemical substances of dillerent volatilities 'and compositions — generally carbo-hydrogens — of which the further sejwration wouhl be a labor of purely scientific curiosity, without having any bearing upon the objects of the present report. Although, therefore, those litpiids were carefully examined, and observations made regarding their chemical history, I shall not embarrass the [jresent repoi-t by jcl'erence to them in any other point of view than as products of destructive distillation whose properties, analogous to the highly volatile and to the fixed oils resi)ectively, may give them a commercial value such as has been represent- ed. I may remaiiv also, that as a purely scientific question, the true nature of the solid fatty product is of much interest. Tlic name parafiine has been given to this body, but iu some of its characters it appears to deviate from those of the true parafiine, as described by Reichenbach to Ije obtahied from wood-tar; those differences should, however, not contra- vene its connnercial uses." See PAnAKFi.NE. "The iucpiiry so far carried on sufficiently established that the peat by destructive dis- tillation in close vessels yielded the several products that had been desciibed, and were identical, or clo.^ely analogous, to those afforded in the distillation of wood or coal. The process in close retorts, however, being not at all that proposed or economically practicable lor commercial purposes, it was necessary to proceed to determine whether the same varieties of peat, being distilled in a blast furnace, with a cuirent of air, so that the heat necessary for the distillation was produced by the combustion of the peat itself, w'ould furnish the same products, and whether in greater or in less quantities than in the process in close vessels. " For this purpose, the cylinder which in the former series of experiments had been set horizontally in the furnace, was placed surrounded by biickwoik vertically, its mouth pro- jecting a little at top, so that the tube for conveying away the products of the distillation passed horizontally from the top of the brickwork casing to the condensing apparatus. Near the bottom of the cylinder the brickwork left a space where the cylinder was perfo- lated by an aperture 1} inch diameter, to which the tube of a large forge bellows was adapted. Tlic arrangement thus represented nearly the construction of an iron cupola. The cylinder being charged with peat, of which some fragments were fiist introduced lighted, and the blast being put on, the combustion spread, and the cover of the cylinder being screwed down, (he distillation proceeded, the products passing over with the current of air into the series of condensing vessels, and the gases and air finally being conducted by a waste pipe to the ashi)it of a fin-uace where they were allowed to escape. "By this means there was obtained, on a moderate scale, a satisf\tctory representation of the condition of air-blast distillation of peat which has been proposed as the commercial process. In so carrying it on several interesting observations were made which will require to be noticed here in a general point of view. "First, as to the nature ami quantities of the products. The specimens of peat ope- rated on were selected as similar to those employed in the former series of which the results have been quoted, and the products similarly treated were found to be, from 100 parts — Watery products - Tarrv products (ia-^cii - Ashes - " These several products having from 100 parts of peat — Ammonia or as Sulphate of ammonia Acetic acid or as Acetate of lime Pyroxylic spirit Volatile oils - Pa:amnc Avrrnire. Maximum. Minimum. 30-714 31-678 29-81 8 2-392 2-510 2-270 62-392 65-041 59-716 4197 7-226 2-493 li further examined, as in the former Avpra?e. Maximum. Minimnra. 0-2S7 0-344 0194 1-110 1-330 0-745 0-207 0-268 0174 0-305 0-.S03 0-256 0-140 0-158 0-106 1-059 1-220 0-946 0-125 0-169 0086 PEAT AND TURF. 909 " It is now important to compare these average results with tnose of the former series obtained by distillation in close vessels : we obtain — Average produce from Average produce hy close distillation. air-blast distillation. Ammonia - - - 0-268 0287 or as Sulphate of ammonia - 1-037 TllO Acetic acid - - - 0-191 0-207 or as Acetate of lime - - 0-280 0-305 Pyroxylic spirit - - 0-146 0-140 Oils - - - - 1-340 1-059 Paraffine - - - 0134 0-125" Experiments were made at the request of Sir Robert Kane, by Dr. Hodges, Professor of Agriculture, to determine the commercial value of the peat products. The quantities and nature of the products, as certified by Dr. Hodges, in the one trial which lie superintended, compared with the Museum average results reduced to the same standard (Dr. Hodges' acetic acid having been 25 per cent, of real) are — Sulphate of ammonia Acetic acid real hydrated - Wood naphtha Tar .... It hence is evident that the "quantity of ammonia obtained at Xewtown Crommelin is rather under that obtained at the JIuseum ; but the produce of acetic acid, tar, and naphtha, has been found in average decidedly inferior to that stated, although the maximum results found in particular trials have approximated closely to Dr. Hodges' numerical results. There having been, however, apparently but a single trial so accurately followed up at Newtown Crommelin, it is necessary to contrast the results of the Museum experiments more specially with the quantitative produce expected by Mr. Rcece. Mr. Recce's statement of the produce from 100 tons of peat distilled is compared with the average results of the Museum trials in the following table : — Professor Ilodcres. Mus ?um. From 100 From 100 From a ton. parts. From a ton. parts. 22 1 lbs. 1-000 247io lbs. 1-110 7i lbs. -328 4J lbs. -207 831 oz. ^232 50'/5 oz. •140 99* lb.s. 4-440 53| lbs. 2-390 Statement in Average results of From Mr. Keece's Museum trials by 100 parts of peat. prospectus. blast process. Sulphate of ammonia - 1-000 1-110 Acetate of lime - •700 •305 Wood naphtha - •185 -140 Paraffine - •104 •125 Fixed oils - •714 ) 1-059 Volatile oils •357 f From this comparison it is evident that the quantity of ammonia obtained is rather greater than that expected by Mr. Reecc ; secondly, that the quantity of paraffine and of oils may be considered the same ; thirdly, that the quantity of wood-naphtha expected by Mr. Reece is more than was obtained in average, but not more than was obtained in some Muse- um trials. That the quantity of acetate of lime expected by Mr. Reece is more than double that which was in average obtained in the Museum, unless the commercial acetate of lime calculated for by Mr. Reece shall contain such excess of lime, &c., as shall render its weight double that which the pure article, calculated in the result of the Museum trials, should have. This latter circumstance may possibly explain the difference. After a minute detail of the numerous experiments made by Dr. W. Sullivan, in the Laboratory of the Museum of Irish Industry, Sir Robert Kane gives the following summary of his results : — "From these considerations of the results of the experiments made in the Museum of Industry, and the trials at Newtown Crommelin, and of the circumstance* of the manufac- ture of the same products from the other species of fuels by proces.ses more or less analogous, it appears to me that some general conclusions may be deduced : — " 1. That the quantities of ammonia, of wood spirit, and of so-called paraffine, lixed and volatile oils, stated by Mr. Reece to l)e obtaineii by distillation from peat, do not apjicar to be exaggerated, as they fall within the limits of the results obtained in the JIu.scum labora- tory, and approach elo.sely to the average results. That the (juantity of acetic acid or acetate of lime, stated by Mr. Recce and Dr. Hodges, could not be obtained, the result of the Museum trials affording but from one-half to two-thirds of the expected (piantity of that substance. Tiiat, fiu'thcr, the ])rothice of jiaralline nuiy possibly be rendered much more considerable than was stated by Mr. Reece, through a more judicious tn^atnient of the resiu- i;u3 materials of the tar than had been proposed by that chemist. 910 PENCIL MANUFACTURE. " 2. That tlio (listilliition with combustion of the peat in the blast furnaces must be con- sidered to produce only the raw materials for the subsequent chemical operations, just as in the processes of wood or coal distillations, there are produced tar and ammonia, and acetic acid, which have long been the objects of manufacture. " 3. That those materials, if cliarpjcd with the total cost of the peat consumed, the cost of erecting and working the furnaces, the Ijlast engines, and condensing apparatus, and proportion of management, would not appear to be very much more economicallj obtained from peat, than they are now obtained from the products of wood and coal distillation, where they are sold at very low prices, and, at least as regards gas tar and gas liquor, in most places in Ireland, have been regarded as waste products. " 4. That the principal value of the d.ass of products obtained from peat is derived from the cost of their subsequent purification and conversion into a commercial form, and that consequently the piincipal advantage of a new mode of obtaining them must be looked for in the more economical treatment of those materials. " 5. That to this principle the extraction of the paraffine may be an exception, it being itself a material new to commerce on a large scale, and hence not having its value deter- mined by the comparative economy of preparation from sources of little value. " 6. That tiie economies introduced in the treatment of the tarry and watery products of peat distillation are reducible to two (so far as I have been able to learn) : — 1 , the separation of the wood spirit, by means of an improved distilling apparatus ; and 2, the utilization of the waste gases from the condensing pipes, so as to supersede the use of other fuel by burn- ing the gas in jets under the steam boilets, tar and acetic acid stills, evaporating pans, &c. " 7. That the former economy cannot be of paramount influence, as it affects but one stage of the preparation of a single product, and further miglit be applied in a similar way to lessen the cost of production of wood spirit from any other source. " 8. That the latter economy is of the most important character, and appears more than any other one condition to influence the probable success of the manufacture on the great scale; that therefore the amount of advantage derived from similar employment of gases in iron-smelting works will deserve careful comparison, and that it will be necessary particular- ly to take into account the difference of combustibility of gaseous mixtures when very hot, as when from an iron furnace, and when quite cold, as from the condensing apparatus of a peal l)last furnace. " 9. That under the circumstances of a manufacture presenting so many new and complex processes, which, in analogous branches of industry, it is found convenient to sep- arate and commit to different and individual interests, and that its conditions, as to the supply of peat, require its establishment in localities of but little industrial activity, it can scarcely be expected that even as much economy and advantage should be realized as might be expected after experience of the same process on a working scale and with trained labor. " 10. That although the excessive returns stated by the proposers of the manufacture may not be olitained, it is yet probable that, conducted with economy and the attention of individual interests, the difficulties connected with so great complexity of operations would be overcome, and the maimfacture l)e found in practice profitable ; and certainly it must be regarded as of very great interest and public utility tiiat a branch of scientific manufacture .should Ijc established, specially applicable to promote the industrial progress of Ireland by conferring a connnercial value on a material which has hitherto been principally a reproach, and bv affording employment of a remunerative and instructive character to our laboring population." PENCIL MANUFACTURE. {Orai/nn.% fabrigw de, Fr. ; Bleixflfte verfn-lir/iinrf. Germ.) The word pencil is used in two senses. It signifies either a small hair biush employed by painters in oil and water-colors, or a slender cylinder of black lead or plumbago, either naked or enclosed in a wooden case, for drawing black lines upon paper. The last sort, which is the one to be considered here, corresponds nearly to the French term crayon, though this includes also pencils made of differently coloi'cd earthy compositions. Tlie best Ijlack-lead pencils of this coimtry are formed of slender parallclopipeds, cut out by a saw, from sound ])iec('s of phnnt):igo, especially such as have been obtained from Borrowdale, in Cumbeiland. These parallclopipeds are generally enclosed in cases made of cedar wooEX. Syn. Pctraffine Oil. A term which has recently found its way into commerce, to designate certain oils or na])hthas for illuminating purposes. It is generally prepared from shales, brown coals, or canncls. Boghead coal, and the numerous varieties of inflammalile shales whicli more or less resemble it, are specially adapted for the prcpaiii- tion of photogen. The chief physical difference between photogen and ordinary coal oils of the same boiling point, is the specific gravity, which with the former varies from 0"820 to 0-830, whereas common co-al naphtha never has a less density than 0850°. It is true that photogen may be obtained of as high a density as 0'900, but then it will be of an ex- cessively high boiling point, and, in all probability, saturated with paraffine. Tiie light oil known as photogen may be obtained from common bituminous coals by distilling them at a lower temperature than is employed in gas works. To obtain the maxi- mum amount of photogen from coal, the temperature should not be much above 700' C. Preparation. — The coals broken in small pieces, the smaller the better, are to be heat- ed in vertical or hoiizontal iron retorts, the tar being received through a very wide worm into large tanks. Some manufacturers use vertical, and others horizontal retorts ; it is also common to distil the coals by tl>c heat produced by their own combustion. If the latter process be employed, the arrangements for condensing the product must be vciy perfect, or great loss will lie sustained, owing to the air which supports the combustion carrying away a considerable quantity of the hydrocarbons. This power of air to saturate itself with vapors, is of gieat importance in the economy of all processes where the distillation of one portion of substance is carried on by the heat evolved by the combustion of another. It is not uncommon in practice, where the cylinders are horizontal, to place the coal or other matters to be distilled in semi-cylindrical trays, which are capable of being inserted into the retorts, and also of being removed to make way for another charge at the completion of the operation. The tar obtained i)y any of the above processes is to be redistilled ; the lighter portions form (when purified by means of sulphuric acid and alkalies) the fluid known in commerce as "Boghead naphtha." See Naphtha, BociiKAn. In Germany and some other places, it is usual to divide the distillate from the tar into two portions, one being for the preparation of [)hotogen, and the other for "solar oil." This division is made as the fluid runs from the still ; the more volatile constituting the photogen, and the less the solar oil. The process of purification is the same in both cases, namely, alternate treatments with concentrated sulphuric acid to remove the highly colored and odorous constituents of the crude distillate, and washing with an alkali to remove carbolic acid and its congeners; also that portion of sulphuric acid which remains suspended in the naphtha, and the sulphurous acid produced by the decomposition of a i)ortion of the sulphuric acid by the carbon of certain easily decomposed organic matters in the crude distillate. This decomposition of the sulphuric acid happens thus : — 2S0'IIO + C = 2.-;O^+ 2110 + 00'. PHOTOGRAPHIC ENGRAVING. 915 There is another advantage in the treatment of the fluid by alkalies, inasmuch as some sulphide of hydrogen, and piobably olhur fa>tid sulphur compounds, is decomposed and the resulting products removed. In preparing photogen from any of the sources enumerated, much must be left to the discretion of the manufacturer both as regards the apparatus and the chemical processes. In some instances the solar oil and photogen are with advantage prepared separately, but in this country it is more usual to mix the heavy and light oils together so as to produce a fluid of medium density and volatility. It must be remembered that while the moie vola- tile hydiocaibons confer extreme inflammability and fluidity, they are at the same time more odorous than the less volatile portion of the distillate, which is the true paraffine oil. The more odorous impurities in photogen appear to be easily susceptible of oxidation. This is evident from the facility with which foully smelling photogen loses its olfensive odor in co:Uact with bichromate or manganate of potash, or even animal charcoal. Their ex- PQBurL^ to air even gi-eat!y improves the odor, and a recently disti.led photogen, which is very unpleasant, becomes comparatively sweet if kept in tanks or barrels ibr a few days. The same thing happens with many essential oils, such as those of peppermint, cloves, &c. Tae presence of sulphurous acid in photogen may be instantly detected by shaking a little in a test tube with a few drops of a very weak solution of bichromate of potash; if sulphu- rous acid be present a portion of the chromic acid will be reduced to green oxide, which will instantly betray the presence of the reducing agent alluded to. Piiotogen often shows the phenomenon of dichroisra, but the more it is purified by acids the more feebly is the coloration by reflected light observed, and if the less volatile portion of the distillate be rejected, the property alluded to will not be perceived. In distilling the heavy oils or tars produced by distilling Boghead coal or other photo- gen-yielding substances, it is particularly to be observed that the worms or other tubes pro- ceeding from the stills, if of too small diameter, are liable to become choked up with paraffine; this, unobserved, might lead to serious results. It is very convenient to have a steam pipe inserted into the worm tubes or condensing tanks, to enable the water to be heated to such a point as to melt any solid matters in the worms, and allow them to be waslied into the recipient by the fluids distilling over. None of the cannel or bituminous coal, shales, or other substances used for yielding burning fluid by distillation, gives distillates of such purity and freedom from odor as Rangoon tar. The more volatile portion of the distillate fiom the latter has obtained in commerce the absurd name of Sherwoodole ; it is used instead of coal benzole, for removing gi-case, &c. The parafline obtained from Rangoon tar has a greater value for commercial purposes than that from Boghead coal, inasmuch as it has a higher melting point, which renders it better adapted for candles. Tlie following are the melting points of various samples of parafline : — McUins point. 114' Fahr. 108° " Boghead coal paraffine " " another specimen - - - - The last, after being distilled 108° " Turf paraffine ] 16' " Bituminous coal paraffine, prepared by Atwood's process - - 110" " Rangoon tar paraffine -.---... 140° " It is curious to observe the effi?ct of light upon photogen. Some samples of extremely dark color, when exposed to its influence for a few days, become as completely bleached as animal oils would under these circumstances. At the same time, as we have before hinted, the odor becomes much improved. A photogen of good quality has by no means a re- pulsive odor, but if much of the more volatile constituents be present, it is impossible to avoid its being disagreeable if spilled about. The less volatile hydiocarbons have compara- tively little odor. It should not be too inflammable, that is to say, it must not take fire on the approach of a light. If it does, it is owing to the more volatile portion not having been sufficicntlv removed. — C. G. W. PHOTOGRAPHIC ENGRAVING. The fir.st who appears to have had any idea of heliograpluc engraving was Nicephore Nicpcc. According to M. Aime Girai-d the first proof taken by him by moans of this process bears date 1827, some dozen years before the publication of Mr. Talbot's PAo/oye?(ic ^roct'-s.vr.s'. This process, wliich is now almost for- gotten. Wits very simple ; it consisted in spreading a thin layer of bitumen of Jiidea upon a copper or pewter plate, which was then placed in the camera obseur.i, where it was allowed to remain some hours, until it had received the im|)ression of the external objects towards which the lens had been directed. On withdrawing the plate it was submitted to tiie action of the essence of lavender, which dissolved the portions of the bitumen not acted upon l)y the light, leaving the metal bare, while the remaining bitumen reproduced the design. Passing tlijc plate afterwards through an acid solution it was found that it had eaten hollows in the metallic plate, while the other parts were preserved by the protecdng varnish. Such was the process that M. Niepce revealed to Daguerre when he entered into a partnership 91 T) PHOTOGRAPHIC EXGRAYIXG. with him. Xifepco died in 1833, after struggling twenty year.a, during wliifh lie spent Lis time and money in endeavoring to perfect his discovery, poor and uln.ost uul^nowu. Six years later, that is in 1839, M. Daguerre made his discovery public. In the mean time he had considerably improved on Niepce's process ; but the introduction of the Calo- type led to the abandonment of the process for some years. The next process to which we shall refer is that of M. Fizeau. He took a daguerreotype plate and submitted it to the action of a mixture of nitric, nitrous, and hydrocliloric acids, which did not affect the whites of the picture but attacked the blacks with a resulting forma- tion of adherent chloride of silver, which speedily arrested the action of the acid. This he removed by a solution of ammonia, and the action of the acid was continued. This process he continued until a finely engraved plate was the result ; but the lines of this plate M-ere not deep enough to allow of prints being taken from it ; and to remedy this, he covered the plate with some drying oil, and then, wiping it from the surface, left it to dry in the hollows. He afterwards submitted the plate to an electro-chemical process which covered the raised parts with gold, leaving the hollows in which the varnish remained untouched. On the completion of the gilding this varnish was removed by means of cau.stic potash, and the surface of the plate covered with c/rahts de grarurc, producing what is technically termed an aquatint ground, and the deepening of the lines was proceeded with by means of the acid. The'Daguerreotype plate was by these means converted into an engraved plate, but as it was silver it would have worn out very soon ; to obviate which an impression was taken on copper by an electro-chemical process, which could of course be renewed when it showed signs of wear. M. Claudet and Mr. Grove both produced some very beautiful engravings on the Daguerreotype plate, but as these processes have proved rather curious than useful, they need not be described. On the 29th of Oct., 1852, Mr. Fox Talbot patented a process, which was similar to the Pkotocalvaxographic process previously used by MM. Pretsch and Poitevin, as regards the sub-stance first used, viz., a mixture of bichromate of potash and gelatine ; but the remaining portion of the process was conducted on the same principle, though in a different manner, to that of M. Fizeau. Mr. Mungo Ponton discovered the use of the bichromate of potash as a photographic agent, and Mr. Robert Hunt subsequently published a process, called the " Chromotype." In both these processes the peculiar property of the chromic acid liberated under the action of sunshine, to combine with organic matter, was pointed out. MM. Pretsch, Poitevin, and Talbot only availed themselves of this previous discovery, and in each instance gelatine was rendered insoluble by the decomposition of the bichromate of potash under the influence of aclinic power. By dissolving off the still soluble portions of the gelatine, cither metal could be precipitated by the voltaic battery, or an etching produced. In 1853 M. Niepce de St. Victor, the nephew of Xicephore Niepce, took up his uncle's plan, and with the assistance of M. Lemaitre, who had also assisted his uncle, endeavored to perfect it ; but though he modified and improved it, his success was not very great ; it was always found necessary to have the assistance of an engraver to complete the plate. After this many t)thers, among whom may be enumerated MM. Lerebours, Lemercier, Barreswil, Davannc, and finally Poitevin, endeavored to obtain a design by similar means on stone. The last appears to have succeeded. His method is based on the chemical re- action of light on a mixture of gelatine and bichromate of potash, as above. This mixture, which when made is perfectly soluble in water, becomes insoluble after exposure to the light. His mode of proceeding is as follows : — lie spreads the mixture on the stone, and after drying lays the negative upon it and exposes it to the light. After a suitable exposure the negative is removed, and the portions not acted upon Ijy the light are washed away with water, and the design remains with the property of taking the ink liko an ordinary lithographic crayon. The stone is then transferred to the press and proofs taken in the usual way. It is .said that excellent pictures have been obtained from the stone after 900 copies had been pulled. The process of M. Charles Niegre, which has excited much attention in Paris, is more complicated than the preceding, but yields superior results. His process appears to be not unlike that of M. Fizeau. He employs acids to cat the lines into the plate, and at a certain stage of the process it is submitted to the action of a galvanic bath which plates it with cojjper, silver, or gold, according to circumstances. By his process the half-tones are pro- duced with much delicacy. Mr. Fox Talbot's process of Photoglyphic Engraving has been thus described by himself: — " I employ plates of steel, copper, or zinc, such as are commonly used by engravers. Before using a plate its surface should be well cleaned ; it should then be rubbed with a linen cloth dipped in a mixture of caustic soda and whiting, in order to remove any remain- ing trace of greasiness.. The plate is then to be ruljbed diy with another linen cloth. This process is then to be repeated ; after which, the plate is in general sufficiently clean. PHOTOGRAPHIC ENGRAVING. 917 " In order to engrave a plate, I first cover it with a substance which is sensitive to light. This is prepared as follows : — About a quarter of an ounce of gelatine is dissolved in eight or ten ounces of water, b\' the aid of heat. To this solution is added about one ounce, by measure, of a saturated solution of bichromate of potash in water, and the mixture is strain- ed through a linen cloth. The best sort of gelatine for the purpose is that used by cooks and confectioners, and commonly sold under the name of gelatine. In default of this, isinglass may be used, but it does not answer 60 well. Some specimens of isinglass have an acidity which slightly corrodes and injures the metal plates. If this accident occurs, ammonia should be added to the mixture, which will be found to correct it. This mixture of gelatine and bichromate of potash keeps good for several months, owing to the antiseptic and preserving power of the bichromate. It remains liquid and ready for use at any time during the summer months; but in cold weather it becomes a jelly, and has to be warmed before using it : it should be kept in a cupboard or dark place. The proportions given above are convenient, but they may be considerably varied without injuring the result. The engraving process should be c.irried on in a partially darkened room, and is performed as follows : — A little of this prepared gelatine is poured on the plate to bo engraved, which is the.i held vertical, and the superfluous liquid allowed to drain off at one of the corners of the plate. It is held in a horizontal position over a spirit lamp, which soon dries the gela- tine, which is left as a thin film, of a pale yellow color, covering the metallic surface, and generally bordered with seveial narrow bands of prismatic colors. These colors are of use to tlie operator, by enabling liim to judge of the thinness of the film : when it is very thin, the prismatic colors are seen over the whole surface of the plate. Such plates often make excellent engravings ; nevertheless, it is perhaps safer to use gelatine films which are a little thicker. Experience alone can guide the operator to the best result. The object to be engraved is then laid on the metal plate, and screwed down upon it in a photographic copy- ing fianie. Such objects may be either material substances, as lace, the leaves of plants, &c., or they may be engravings, or writings, or photographs, &c., &c. The plate bearing the object upon it is then to be placed in the sunshine, for a space of time varying from one to several minutes, according to circumstances ; or else it may be placed in common day- light, but of course for a long time. As in other photographic processes, the judgment of the operator is here called into play, and his experience guides him as to the proper time of exposure to the light. When the frame is withdrawn from the light, and the object re- moved fiom the plate, a faint image is seen upon it — the yellow color of the gelatine having turned brown wherever the light has acted. "Tlie novelty of the present invention consists in the improved method by which the photograpiiic image, obtained in the manner alcove described, is engraved upon the metal plate. The first of these improvements is as follows : — I formerly supposed that it was necessary to wash the plate, bearing the photographic image, in water, or in a mixture of water and alcohol, which dissolves only those portions of the gelatine on which the light has not acted ; and I believe that all other persons who have employed this method of engrav- ing, by means of gelatine and bichromate of potash, have followed the same method, viz., that of washing the photographic image. But however carefully this process is conducted, it is frequently found, when the plate is again dr}', that a slight disturbance of the image has occurred whicli, of course, is injurious to the beauty of the result; and I have now ascertained that it is not at all necessary to wash the photographic image ; on the contrary, much more beautiful engravings are obtained upon plates which have not been washed, becaijse the more delicate lines and details of the picture have not been at all disturbed. The process which I now employ is as follows: — When the plate, bearing the photograjihic image, is leniovod from the copying frame, I spread over its surface, carefully and very eveidy, a little finely-powdered gum copal (in default of which common resin may be cm- ploycil). It is much easier to spread this resinous powder evenly upon the surface of gela- tine, than it is to do so upon the naked surfiice of a metal plate. The chief error the operator has to guard against is, that of putting on too much of the powder : the best results are oI)tained by using a very thin layer of it, jirovided it is uniforndy distributed. If too much of the powder is laid on it impedes the action of the etching liipiid. When the plate has been thus very thinly powdered with copal, it is held horizoutally over a sjiirit lamp in ordei- to melt the co|)al ; this re(iun'es a considerable heat. It might be supposed that this heating of the plate, alter the formation of a delicate photograpiiic image upon it, would distuH) and injure that image ; but it has no such elfect. . The melting of the copal is known by the change of color. The plate should then be withdiawn from the lamp, and suffered to cool. Tiiis process may be called the laying an a(iuatint ground ui)on the gelatine, and 'I believe it to Ije a new process. In the common mode of laying an aquatint giound, the • resinous particles are laid iqion the naked stnl'ace of the metal, before the engraving is commenced. The gelatine being tiius covereil with a layer of copal, disseminated uniforndy and iu minute particles, the etching rK|uid is to be jxiured on. This is prejiared as lol- lop.- : — Muriatic acid, otlierwise called liyilrochloric a''iil, is saturated with peroxide of iron, as much iLs it will dis.solvc with the aid of heat. After stiainiug the solution, to remove 918 PHOTOGRAPHY. imptiritios, it is cvapoiated till it is considerably reduced in volume, and is tlien poured off into bottles of a convenient capacity ; as it cools it solidiiies into a brown semi-crystalline nia.-s. The bottles are then well corked up, and kept for use. I shall call this preparation of iron by the name of pcrchloride of iron in the present specification, as I believe it to be identical with t'le substance described by chemical authors under that name — for example, see 7'iinicr\s Ch.i>iixtr;j, fifth edition, pa<;e 5y7 ; and by others called permuriate of iron — lor example, see Bru^rs JLninul of C/iei/us/rt/, second edition, vol. ii. page 117. " It is a substance very attractive of moisture. "When a little of it is taken from a bottle, in the form of a dry powder, and laid upon a plate, it quickly deliquesces, absorbing the atmospheric moisture. In solution in water, it forms a yellow liquid in small thicknesses, but chesnut-brown in greater thicknesses. In order to render its mode of action in photo- grapliic engraving more intelligible, I will first state, that it can be very usefully employed in common etching ; that is to say, if a plate of copper, steel, or zinc is covered with an etching ground, and lines are traced on it with a needle's point, so as to form any artistic subject ; then, if the solution of perchloride of iron is poured on, it quickly effects an etch- ing, and does this without disengaging bubbles of gas, or causing any smell ; for which reason it is much more convenient to use than aquafortis, and also because it does not in- jure the operator's hands or his clothes if spilt upon them. It may be employed of various strengths for common etching, but requires peculiar management for photoglyphic engrav- ing ; and as the success of that mode of engraving chiefly turns upon this point, it should be well attended to. " Water dissolves an extraordinary quantity of perchloride of iron, sometimes evolving much heat during the solution. I find that the following is a convenient way of pro- ceeding: — "A bottle (Xo. 1) is filled with a saturated solution of perchloride of iion in water. " A bottle (Xo. 2) with a mixture, consisting of live or six parts of the saturated solution and one part of water. " And a bottle (Xo ?>) with a weaker liquid, consisting of equal parts of water and the saturated solution. Before attempting an engraving of importance, it is almo.-t essential to make i)reliminary trials, in order to ascertain that tliese liquids are of the proper strengths. These trials I shall therefore now proceed to point out. I have already explained how the photographic image is made on the surface of the gelatine, and covered with a thin layer of powdered copal or resin, which is then melted by holding the plate over a lamp. When the jilite has become perfectly cold, it is ready for the etching process, which is performed as follows • — A small (luantity of the solution in bottle Xo. 2, viz. that consisting of five or six paits of the saturated sohition to one of water, is poured upon the plate, and spread witli a camel-hair brush cveidy all over it. It is not necessary to make a wall of wax round the plate, because the quantity of liquid employed is so small that it has no tendency to rim otfthe plate. The liquid penetrates the gelatine wherever the light has not acted on it, but it refuses to penetrate those parts upon which the light has sufficiently acted. It is upon this remarkable fact that the art of photoglyphic engraving is maiidy founded. In aliout a minute tlie etching is seen to begin, which is known by the parts etched turning d.u k brown or black, and then it spreads over the whole plate — the details of the picture appealing with great rapidity in every ([uarter of it. It is not desirable that this rapidity should be too great, for, in that case, it is necessary to stop the process before the etcliing has ac(iuired sufficient depth (which recjuires an action of some minutes' duration). If, therefore, the etching, on trial, is found to proceed too rapidly the strength of the liquid in bottle Xo.* 2 must be altered (l)y adding some of the saturated solution to it before it is employed for another engraving); but if, on the contrary, the etching fails to occur after the lapse of some minutes, or if it begin.s, but proceeds too slowly, this is a sign that the li.|Uid ill bottle Xo. 2 is too strong, and too nearly ajjpioacliing saturation. To correct this, a little water must lie added to it before it is employed for another engraving. But, in doing this, the operator must take notice, tliat a very minute (piantity of water added often mikes a great dilference, and causes the li(iuid to etch very rapidly. He will therefore be careful in adding water, not to do so too freely. When the proper strength of the solution in bottle Xo. 2 has thus been adjusted, which generally requires three or four expeiiinental trial.-i, it can be employed with .security. Supposing, then, that it has been ascertained to be of the riglit stiength, the etching is commenced, as above mentioned, and proceeds till ail the details of the ])icture have l)een visible, and present a .satisfactory a{)peaiance to the eye of the operator, which generally occuis in two oi- three minutes; the operator stirring the liquid all the time with a camel-hair bru.sh, and thus .-flight ly rubbing the surface of the gelaiiue, which has a good effect. When it seems likely that the etching will improve no fuither, it must be slopped. This is done by wiping off the li(iuid with cotton wool, and then rapidly pouring a stream of cold water over the plate, which carries off all the remain- der of it. The plate is then wiped with a clean linen cloth, and then rubbed with soft whiiiii'r and water to remove the gelatine. The etcliing is then found to be completed. i'llUTUGRAI'ilV. (From photo, light; (/ruph:,ii writing or a description.) The art PHOTOGKAPHY. 919 of producing pictures by the agency of sunshine, acting upon chemically prepared papers. The name appears unfortunate, since we are persuaded that it is not light — that is, the. luminous principle of the sunshine, which effects tlie chemical change, but a peculiar prin- ciple or power which is associated with light in the sunbeam. In the metaphysical refine- ments of our modern philosophy, which endeavors to refer every physical i)henomenon to some peculiar mode of motion, we are apt to lose sight of the stern facts, which, in spite of the enormous amount of talent which has been brought to bear on the whole series of un- dulatory hypotheses, still stand out as unreconeilable with any of these views. If llglit is motion, and shaihw degrees of repose, it remains unexplained how the most intense inotion, yellow light, not only produces no chemical change, but actually prevents it ; or how the deep shadow of the non-luminoux rays produces the most active chemical decomposition. M. Xiepce, in 1827, called his interesting discovery Hkliography, or sun-writing. This name, as involving no hypothesis, was an exceedingly happy one, and it is to be regretted that it was not adopted. In this dictionary it is our purpose only to deal with the chief principles involved in this very interesting art, and to give brief descriptions of some of the more remarkable and interesting of the processes which have been introduced. There are certain chemical com- pounds, and especially some of the salts of silver, which are rapidly decomposed by the iiithii'ncft of the sunshine, and even, though more slowly, by ordinary daylight, or powerful artificial light. As the extent to which the decomposition is carried on depends upon the intensity of radiation proceeding from the object, or passing through it, accordingly as we are employing the reflected or the transmitted rays, it will be obvious that we shall obtain very delicate gradations of dai-kening, and thus the photograph will represent in a very refined manner all those details which are rendered visible to the eye by light and shadow. There are two methods by which photographs can be taken : the first and simplest is by supcr-positio7i ; but this is applicable only to the copying of engravings of such botanical specimens as can be spread out upon paper, and objects which are entirely or in part trans- parent. The other method is by throwing upon the prepared paper the image obtained by the use of a lens fitted into a dark box — the camera obscura. To carry out either of those methods, certain sensitive surfaces must be produced ; these, therefore, claim our first attention : — The artist requires 1. Nitrate of silver. 2. Ammonia nitrate of silver. 3. Chloride of silver. 4. Iodide of silver. 5. Bromide of silver. Those five chemical compounds may be regarded as the agents most essential in the prepa- ration of photographic surfaces. 1. Nitrate of Silver. The crystallized salt should, if possible, always be procured. The fused nitrate, which is sold in cylindrical sticks, is more liable to contamination, and the paper in which each stick of two drachms is wrapped being weighed with the silver, ren- ders it less economical. A preparation is sometimes sold for nitrate of silver, at from Gd. to 9d. the ounce less than the ordinary price, which may induce the unwary to purchase it. Tliis reduction of price is effected by fusing with the salt of silver a proportion of some cupreous salt, generally the nitrate, or nitrate of potash. This fraud is readily detected by oljSLTving if the salt becomes moist on exposure to the air — a very small admixture of cop- per rendering the nitrate of silver deliquescent. The evils to the photographer are, want of sensibility upon exposure, and the perishability (even in the dark) of the finished drawing. The most simple kind of photographic paper which is prepared, is that washed with the nitrate of silver only ; and for many purposes it answers remarkably well, particularly for copying lace or feathers ; and it has this advantage over every other kind, that it is perfectly fixed by well soaking in pure warm water. The best proportions in which this salt can be used arc 60 grains of it dissolved in a fluid ounce of water. Care must be taken to apply it equally, witli a quick but steady mo- tion, over every part of the paper. It will be found the best practice to pin the sheet by its four corners to a flat board, and then, holding it with the left hand a little inclined, to sweep the brusli from the upper outside corner, over the whole of the sheet, removing it as seldom as possible. The nitrated paper not Vjcing very sensitive to hnninous agency, it is desirable to increase its power. This may be done to some extent by simple metliods. By soaking the pajier in a solution of isinglass or parchment size, or by rubbing it over with the white of egg, and drying it prior to the application of the sensitive wash, it will be found to blacken much more readily, and assume different tones of color, which may be ▼arii'd at the taste of the operator. By dissolving the nitrate of silver in common rectified sjjirits of wine instead of water, we produce a tolerably sensitive nitrated paper, wiiicli darkens to a very h(>Mutirul chocolate 920 PHOTOGRAPHY. brown ; but this wash must not be used on any sheets prepared with isinglass, parchment or albumen, as these substances are coagulated by alcohol. 2. Ammonia Nitrate of Silver. Liquid ammonia is to be dropped carefully into nitrate of silver ; a dark oxide of silver is thrown down ; if the ammonia liquor is added in excess, this precipitate is redissolved, and we obtain a perfectly colorless solution. Paper washed with this solution is more sensitive than that prepared with the ordinary nitrate. ?>. CiiLORiiiE OF Silver. This salt is obtained most readily by pouring a solution of common salt, chloride of sodium, into a solution of nitrate of silver. It then falls as a pure white precipitate, which rapidly changes color even in diffused daylight. Chloridated jjupcrs, as ihcy are termed, arc formed by producing a chloride of silver on their surface, by washing the paper with the solution of chloride of sodium, or any other chloride, and when the paper is dry, with the silver solution. It is a very instructive practice to prejiare small quantities of solutions of common salt and nitrate of silver of different strengths, to cover slips of paper with thom in various ways, and then to expose them all to the same radiations. A curious variety in the degrees of sensibility, and in the intensity of color, will be detected, showing the impoi'tance of a very close attention to proportions, and also to the mode of manipulating. A knowledge of these preliminary but important points having been obtained, the prepa- ration of the paper should be proceeded with ; and the following method is recommended : Taking some flat deal boards, perfectly clean, pin upon them, by their four corners, the paper to be prepared ; observing the two sides of the paper, and selecting that side to re- ceive the preparation which presents the hardest and most uniform surface. Then, dipping a sponge brush into the solution of chloride of sodium, a sufficient quantity is taken up by it to moisten the surface of the paper without any hard rubbing ; and this is to be applied with great regularity. The papers being " salted," are allowed to dry. A great number of these may be prepared at a time, and kept in a portfolio for use. To render these sensi- tive, the papers being pinned on the boards, or carefully laid upon folds of white blotting- paper, are to be washed over with the nitrate of silver, applied by means of a camePs-hair pencil, observing the instructions previously given as to the method of moving the brush upon the paper. After the first wash is applied, the paper is to be dried, and then sub- jected to a second application of the silver solution. Thus prepared, it will be sufficiently sensitive for all purposes of copying by application. T7ie most sensitive paper. — Chloride of sodium, 30 grains to an ounce of water ; nitrate of silver, 120 grains to an ounce of distilled water. The paper is first soaked in the saline solution, and after being carefully wiped with linen, or pressed between folds of blotting-paper and dried, it is to be washed twice with the solu- tion of silver, drying it by a warm fire between each washing. This paper is very liable to become brown in the dark. Although images may be obtained in the camera obscura on this paper by about half an hour's exposure, they are never very distinct, and may be re- garded as rather curious than useful. Less sensitive paper for copies of cneiravivgs or botanical specimens. — Chloride of so- dium, 25 grains to an ounce of water ; nitrate of silver, 99 grains to an ounce of distilled water. Common sensitive paper, for copying lace-icork, feathers, d'c. — Chloride of sodium, 20 grains to an ounce of water ; nitrate of silver, 60 grains to an ounce of distilled water. This paper keeps tolerably well, and, if carefully prepared, may always be depended upon for darkening equally. 4. Iodide of Silver. This salt was employed very early by Talbot, (see Calotype, vol. i.,) Ilcrschel, and others, and it enters as the principal agent into Mr. Talbot's calotype paper. Paper is washed with a solution of the iodide of potassium, and then with nitrate of silver. By this means papers may be prepared which are exquisitely sensitive to lumi- nous influence, provided the right proportions are hit ; but, at the same time, nothing can be more insensible to the same agency than the pure iodide of silver. A singular difference in precipitates to all appearance the same led to the belief that more than one definite cou)- pound of iodine and silver existed ; but it is now proved that pure iodide of silver will not change color in the sunshine, and that the quantity of nitrate of silver in excess regulates the degree of sensibility. Experiment has proved that the blackening of one variety of iodated paper, and the preservation of another, depend on the simple admixture of a very minute excess of the nitrate of silver. The papers prepared with the iodide of silver have .'ill the peculiarities of those prepared with the chloride, and although, in some instances, they seem to exhibit a much higher order of sensitiveness, they cannot be rccommer^lcd for general purposes with that confidence which experience has given to the chloride. u. Bromide of Silver. In many of the works on chemistry, it is stated that the chfo- ride is the most sensitive to light of all the salts of silver ; and, when they arc exposed in a perfectly formed and pure state to solar influence, it will be found that this is nearly cor- rect. Modern discovery has, however, ."shown that these salts may exist in peculiar condi- tions, in which the affinities are so delicately balanced as to be disturbed by the faintest PHOTOGRAPHY. 921 gleam ; and it is singular that, as it regards the chloride, iodide, and bromide of silver, when in this condition^ tlie order of sensibility is reversed, and the most decided action is evident on the bromide before the eve can detect any change in the chloride. To prepare a higbly sensitive paper of this kind, select some sheets of very superior glazed post, and wash it on one side only with bromide of potassium — iO grains to 1 ounce of distilled water, over which, when dry, pass a solution of 100 grains of nitrate of silver in the same quantity of water. The paper must be dried as quickly as possible without es- posin"' it to too much heat ; then again washed with the silver solution, and diied in the dark.° Such are the preparations of an ordinary kind, with which the photographer will proceed to work. The most simple method of obtaining suu-pictures, is that of placing the objects to be copied on a piece of prepared paper, pressing them close by a piece of glass, and exposing the arrangement to sunshine : all the parts exposed darken, while those covered are pro- tected from change, the resulting picture being white upon a durk ground. For the muhrplication of photogniphic drawings, it is necessary to be provided with a frame and glass, called a copying frame. The glass must be oi such thickness as to resist considerable pressure, and it should be selected as colorless as possible, great care being taken to avoid such as have a tint of yellow or red, these colors preventing the permeation of the most efficient rays ; fig. 559 represents the frame, showing the back, with its ad- justments for securing the close contact of the paper with every part of the object to be copied. Having placed the frame face downward, carefully lay out on the glass the object to be copied, on which place the photographic paper very smoothly. Having covered this with the cushion, which may be either of flannel or velvet, fix the back, and adjust it by the bar, until every part of the object and paper is in the closest possible contact ; then turn up the frame and expose to sunshine. It should be here stated, once for all, that such pictures, howsoever obtained, are called negative photographs ; and those which have their lights and shadows correct as in nature — dark upon a light ground — are positive photographs. The mode of effecting the produc- tion of a positive is: having, by fixing, given permanence to the negative picture, it is placed, face down, on another piece of sensitive paper, when all the parts which are white on the first, admitting light freely, cause a dark impression to be made on the second, and the resulting image is correct in its lights and shadows, and also as it regards right and left. For obtaining pictures of external nature, the camera obscura of Baptista Porta is cm- ployed. 6G1 562 The figures {figs. 560, 561, 5C2) represent a perfect arrangement, and. at the same time, one which is not essentially expensive. Its conveniences are those of folding, {Jig. 562,) and thus packing into a very small compass, for the convenience of travellers. I'ig. 560 exhibits the instrument complete. Fig. 561 shows the screen in which the sensitive paper is placed, the shutter being up and the frame open that its construction may be seen. 922 PHOTOGRAPHY. 563 5i34 Camera obscuras of a more elaborate character are constructed, and many of exceeding ingenuity, wliich give every f^icility for carrying on tbe manipulations for the collodion process, to be presently described, out of doors. The preceding is a camera obscura of this kind, manufactured by Mr. John Joseph Griffin, of Bunhill Row. This is really Mr. Scott Archer's camera obscura improved upon. Fig. 563 is a section of the instrument, and Jig. 5G4 its external form. With a view to its portability, it is con- structed so as to serve as a packing-case for all the apparatus required, a is a sliding door wliich supports the lens, b. c, c, are side openings fitted with cloth sleeves to admit the operator's arms. J is a hinged door at the back of the camera, which can be supported like a table by the hook c. f is the opening for looking into the camera during an operation. This opening is closed when necessary by the door g, which can be opened by the hand passed into the camera through the sleeves c. The yellow glass window which admits light into the camera during an operation is under the door h. i is the sliding frame for holding the focusing glass, or the frame with the prepared glass, cither of which is fastened to the sliding frame by the check k. The frame slides along the rod / /, and can be fitted to the proper focus by means of the step m. n is the gutta-percha washing-tray, o is an opening in the bottom of the instrument near the door, to admit the well p, and which is closed when the well is removed by the door. The well is divided into two cells, one of which contains the focusing glass, and the other the glass trough, each in a frame adapted to the sliding frame i. On each side of the sliding door that supports the lens «, there is within the camera a small hinged table, ?-, supported by a bracket, s. These two tables serve to sup- PHOTOGRAPHY. 923 port the bottles that contain the solutions necessary to be applied to the glass plate after its exposure to the lens. For supporting any of these camera obscuras, tripod stands are employed ; these are now made in an exceedingly convenient form, being light, af the same time that they are sufficiently firm to secure tlie instrument from any motion during the operation of taking a ])icture. The true photographic artist, however, will not be content with a camera obscura of this or any otiicr kind. lie will provide himself with a tent, in which he may be able to pre pare liis plates, and subsequently to develop and to fix liis pictures. Many kinds of tent have been brought forward, but we have not seen any one which unites so perfectly all that can be desired, witliin a limited space, and which shall have the great recommendation of lightness. Fig. 5f)5 represents Smartt's new photographic tent, which appears to meet nearly all the conditions required. In this tent an endeavor has been made to obviate many of the inconveniences com- plained of, especially as to working space, firmness, siniplicit}., and portability. Usually, in tlio various forms of tent, the upper part, where space is most required, is the most con- tracted, while at the lower part, where it is of little importance, a great amount of room is provided. Smartt's tent, made by Murray k Heath, is rectangular in form, is G feet high in the clear, and 3 feet square, affording table space equal to ;5() inches by ]8 inches, and ample room for the operator to manipulate with perfect ease and convenience. The chief feature in its construction is the peculiarity of its framework, which constitutes, when erected, a system of triangles, so disposed as to strengthen and support each other: it thus combines the two important qualities of lightness and rigidity. The table is made to fold up when not in use ; and in place of the ordinary dish for developing, a very efficient and portable tray is provided, made of india-rubber cloth, having its two sides fixed and rigid and its two 924 PHOTOGRAPHY. ends movable ; it thus folds up into a space but little larger than one of its sides. The working .«pace of the tal)le is economized thus : — a portion of it is occupied by the tray just described ; the silver-bath (which is one of Murray & Heath's new glass baths, with' glass water-tight top) is suspended from the front of the table, and rests upon a portion of the framework of the tent ; a contrivance is devised for disposing of the plate-slide of the camera, in order to reserve the space it would require if placed on the table. The bath and jjlate-holder, in their places as described, are shown in the wood-cut. This arrangement Itjaves ample space on the table for manipulating the largest-sized plates. The entire weight of the tent is 20 lbs., and it is easily erected or taken down by one person. The collodion pourer, the plate-developing holder, the developing cups, and the water- bottle, (the latter is suspended over the tray as in the wood-cut,) have all special points in construction. The object of the inventor has been completely realized, the operator being insured the means of working the wet-collodion process in the open air with ease, comfort, and conve- nience. Hitherto this has not been possible, in consequence of the great weight and bulk of the contrivances used, and to which niay be traced the existence of the many expedients for retaining, inore or less, the sensitiveness of thf> prepared plate. The object of the inventor has been to make a tent whicli shall be so efficient as to en- sure to the operator the means of working the wet collodion process in the open air with ease, comfort, and convenience. The processes of most importance may be divided as follows : — 1. The copying process, already described. 2. The Daguerreoti/pe, the earliest method successfully employed for obtaining pictures by means of the camera obscura. See Daguerkeottpk. 3. The Calotype of Mr. H. Fox Talbot, in which the sensibility of the iodide of silver is exalted by the agency of that peculiar organic compound, gallic acid. See Calotype. 4. The Collodion process, which must be succinctly described h( reaftcr. In addition to the ordinary form of the calotype process as devised by Mr. Fox Talbot, and of which an account has been given under the proper head, the Wax-pjaper process de- mands some attention. The following directions are those given by Mr. Wm. Crookes, who has devoted much attention to, and who has been eminently successful with, the wax- paper: — The first operation to be performed is to make a slight pencil-mark on that side of the paper which is to receive the sensitive coating. If a sheet of Canson's paper be examined in a good light, one of the sides will be ibund to present a finely reticulated appearance, while the other will be perfectly smooth ; this latter is the one that sliould be marked. FilYy or a hundred .sheets may be marked at once, by holding a pile of them firmly by one end, and then bending the packet round, until the loose ends separate one from another like a fan : generally all the sheets lie in the same direction, therefore it is only necessary to ascertain that the smooth side of one of them is uppermost, and then draw a pencil once or twice along the exposed edges The paper has now to be saturated with white wax. The wax is to be made perfectly liquiJ, and then the sheets of paper, taken up singly and l;eld by one end, are gradually lowered on to the fluid. As soon as the wax is absorbed, which takes place almost directly, they are to be lifted up witli rather a quick movement, held by one corner, and allowed to drain until the wax, ceasing to run off, congeals on the surface. "When the sheets are first taken up for this operation, they should be briefly examined, and such as show the water- mark, contain any i)lack spots, or have any thing unusual about their appearance, should be rejected. Tiie paper in this stage will contain far more wax than necessary ; the excess may be removed by placing the .sheets singly between blotting-paper, and ironing them ; but this is wasteful, and the loss may be avoided by placing on each side of the waxed sheet two or three sheets of unwaxed photographic paper, and then ironing tlie whole between blotting- paper ; there will generally be enough wax on the centre sheet to saturate fully those next to it on each side, and partially, if not entirely, the others. Tliose that are imperfectly waxed may be made the outer sheets of the succeeding set. Finally, each sheet must be separately ironed between blotting-paper, until the g'istcning patches of wax are absorbed. It is of the utmost consequence that the temperature of the iron should not exceed that of l)oiling water. Before using, always dip it into water until the hissing entirely ceases. This is one of the most important points in the whole process, but one wh.ich it is very diffi- cult to make beginners properly appreciate. The disadvantages of having too hot an iron are not apparent until an alter stage, while the saving of time and trouble is a great temp- tation to lieginners. A woll-waxed sheet of paper, when viewed by obliquely reflected light, ought to present a perfectly uniform glazed appearance on one side, wh.ilo th > other should be rather duller ; there must he no shining patches on any part of the siir ac, nor should any irregularities be observed on examining the paper with a black ground placed behind ; seen by transmit- PHOTOGRAPHY. 925 ted light, it will appear opalescent, but there should be no approach to a granular structure. The color of a pile of waxed sheets is slightl}' bluish. The paper, having undergone this preparatory operation, is ready for iodizing ; this is effected by completely immersing it in an aqueous solution of an alkaline iodide, either pure or mixed with some analogous salt. Bromide of potassium is sometimes added, and with much advantage in many cases, to the iodizing bath. The addition of a chloride has been found to produce a somewhat simi- lar effect to that of a bromide, but in a less marked degree. No particular advantage, how- ever, can be traced to it. The best results are obtained when the iodide and bromide are mixed in the proportion of their atomic weights, the strength being as follows : — Iodide of potassium 582"o grains. Bromide of potassium 417 '5 grains. Distilled water -.-' 40 ounces. When the two salts have dissolved in the water, the mixture should be filtered ; the bath will then be fit for use. At first a slight difficulty will be felt in immersing the waxed sheets in the liquid with- out enclosing air-bubbles, the greasy nature of the surface causing the solution to run off. The best jvay is to hold the paper by one end, and gradually to bring it down on to the liquid, commencing at the other end ; the paper ought not to slant toward the surface of the bath, or there will be danger of enclosing air-bubbles ; but while it is being laid down, the part out of the liquid should be kept as nearly as possible perpendicular to the surface of the liquid ; any curling up of the sheet when first laid down may be prevented by breath- ing on it gently. In about ten minutes the sheet ought to be lifted up by one corner, and turned over in the same manner ; a slight agitation of the dish will then throw the liquid entirely over that sheet, and another can be treated in like manner. These sheets must remain soaking in this bath for about three hours ; several times dur- ing that interval (and especially if there be many sheets in the same batli) they ought to be moved about and turned over singly, to allow of the liquid penetrating between them, and coming perfectly in contact with every part of the surface. After they have soaked for a sufficient time, the sheets should be taken out and hung up to dry ; this is conveniently effected by stretching a string across the room, and hooking the papers on to this by means of a pin bent into the shape of the letter S. After a sheet has been hung ujj for a few min- utes, a piece of blotting-paper, about one inch square, should be stuck to the bottom corner to absorb the drop, and prevent its drying on the sheet, or it would cause a stain in the j)icture. While the sheets are drying, they should be looked at occasionally, and the way in which the liquid on the surface dries noticed ; if it collect in drops all over the surface, it is a sign that the sheets have not been sufficiently acted on by the iodizing bath, owing to their hav- ing been removed from the latter too soon. The sheets will usually during drying assume a dirty pink appearance, owing probably to the liberation of iodine by ozone in the air, and its subsequent combination with the starch and wax in the paper. This is by no means a bad sign, if the color be at all uniform ; but if it appear in patches and spots, it shows that there has been some irregular absorption of the wax, or defect in the iodizing, and it will be as well to reject sheets so marked. As soon as the sheets are quite dry, they can be put aside in a box for use at a future time. There is a great deal of uncertainty as regards the length of time the sheets may be kept in this state without spoiling. Mr. Crookes speaks from experience as to there being no sensible deterioration after a lapse of ten months. Up to this stage, it is immaterial whether the operations have been performed by day- light or not ; but the subsequent treatment, until the fixing of the picture, must be done by yellow light. The next step consists in rendering the iodized paper sensitive to light. Although, when extreme care is taken in this operation, it is hardly of any consequence when this is per- formed ; yet, in practice, it will not be found convenient to excite the paper earlier than about a fortnight before its being required for use. The materials for the exciting bath arc nitrate of silver, glacial acetic acid, and water. The following bath is recommended : — Nitrate of silver 300 grains. Glacial acetic acid - - 2 drachms. Distilled water 20 ounces The nitrate of silver and acetic acid are to be added to the water, and when dissolvcfl, filtered into a clean dish, taking care that the bottom of the di.sh be flat, and that the liquid cover it to the depth of at least half an inch all over ; by the side of this, two similar dishes must be placed, each containing distilled water. A sheet of iodized paper is to be taken by one end, and gradually lowered, the marked 926 PHOTOGRAPHY. side downward, on to the exciting solution, taking care that no liquid gets on to the back, and no air-bubbles are enclosed. It will be necessary for the sheet to remain on this bath from five to ten minutes ; but it can generally be known when the operation is completed by the change in appearance, the yink color entirely disappearing, and the sheet assuming a pure homogeneous straw color. AV'hen this is the case, one corner of it must be raised up by tlse platinum spatula, lifted out of the dish with rather a quick movement, allowed to drain for about half a minute, and then floated on the surface of the water in the second dish, while another iodized sheet is placed on the nitrate of silver solution ; when this 1 as remained on for a suflicient time it must be in like manner transferred to the dish of distilled water, having removed the pre- vious sheet to the next dish. A third iodized sheet can now be excited, and when this is completed, the one first ex- cited must be rubbed pei-fectly dry between folds of clean blotting-paper, wrapped up in clean paper, and preserved in a portfolio until required for use ; and the others can be transferred a dish forward, as before, tidcing care that each sheet be washed twice in dis- tilled water, and that at every fourth sheet the dishes of washing water be emptied and re- I)Icnished with clean distilled water ; this water should not be thrown away, but preserved in a bottle for a subsequent operation. The above quantity of the exciting bath will be found quite enough to excite about fifty sheets of the size here employed, or 3,000 square inches of [i.-ijier. Of course these sensitive sheets must be kept in perfect darlcness. Generally, sufficient attention is not paid to this point. It should be Ijorne in mind, that an amount of white light, f[uitc harmless if the paper were only exposed to its action for a few minutes, will intallibly destroy it if it be allowed to have access to it for any length of time ; therefore, the longer the sheets are required to be kept, the more carefully must the light, even from gas, be excluded ; they must likewise be kept away from any fumes or vapor. Experience alone can tell the proper time to expose the sensitive paper to the action of light, in order to obtain the best effects. However, it will be useful to remember, that it is almost always possible, however short the time of exposure, to obtain some trace of effect by prolonged development. Varying the time of exposure, within certain limits, makes very little difference on the finished picture ; its principal effect being to shorten or prolong the time of development. Unless the exposure to light has been extremely long, (much longer than can take place under the circumstances we are contemplating,) nothing will be visible on the sheet after its removal from the instrument more than there was previous to exposure ; the action of the light merely producing a latent impression, which requires to be developed to render it visible. The developing solution in nearly every case consists of an aqueous solution of gallic acid, with the addition, more or less, of a solution of nitrate of silver. An improvement on the ordinary method of developing with gallic acid, formed tlie subject of a communication from Mr. Crookes to the F/iilosop/iical Mafjaziite for March, 1855, who recommends the employment of a strong alcoholic solution of gallic acid, to lie diluted with water when required for use, as being more economical both of time and trouble than the preparation of a great quantity of an aqueous solution for each operation. The solution is tints made : Put two ounces of crystallized gallic acid into a dry flafk with a narrow neck ; over this pour six ounces of good alcohol, (00° over jiroof,) and place the flask in hot water until the acid is dissolved, or nearly so. This will not take long, espe- cially if it be well shaken once or twice. Allow it to cool, then add half a drachm of gla- cial acetic acid, and filter the whole into a stoppered bottle. The developing solution for one set of sheets, or 180 square inches, is prepared by mix- ing together ten ounces of the water that has been previously used for washing the excited papers, and -i drachms of the exhausted exciting bath ; the mixture is then filtered into a peifeedy clean dish, and half a drachm of the above ahoholie solution of gallic acid poured into it. The dish must be shaken about until the greasy appearance is quite gone from the surface •, and then the sheets of paper may be laid down on the solution in the ordinary manner with the marked side downward, taking particular care that none of the solution gets on the back of the paper, or it will cause a stain. Should this happen, cither dry it with blotting-paper, or iumierse the sheet entirely in the liquid. If the paper has been exposed to a moderate light, the picture will begin to appear within five minutes of its being laid on the sohition, and will be finished in a few hours. It may, however, sometimes be requisite, if the light has been feeble, to prolong the develop- ment for a day or more. If the dish be perfectly clean, the developing solution will remain active for the whole of this time, and when used only for a few hours, will he quite clear and colorless, or with the faintest tinge of brown ; a darker appearance indicates the pres- ence of dirt. The progress of the development may be watched, by gently raising one cor- ner with the platinum spatula, and lifting the sheet up by the finger.*;. This should not be done too often, as there is always a risk of producing stains on the surface of the picture. PHOTOGEAPHT- _ 927 As soon as the picture is judged to be sufficiently intense, it must be removed from the gallo-nitrate, and hiid on a dish of water, (not necessarily distilled.) In this state it may remain until the final operation of fixing, which need not be })erformed immediately, if in- convenient. After being washed once or twice, and dried between clean blotting-paper, the picture will remain unharmed for weeks, if kept in a dark place. Some general remarks on Ihe fixing processes will be found toward the end of this article. The Collodion Process. The difficulty with which we are met in any attempt to describe this photographic process is, that it is almost hopeless to find two photographers who adopt precisely the same order of manipulation ; and books almost without number have been pubhshed, each one recom- mending some special system. By general consent "the discovery of the collodion process, as now employed, is given to the late Mr. Scott Archer. It will, therefore, be considered quite sufficient to give the details of his process, which has really been but little improved on since its first intro- duction. To prepare the collodion. — Thirty grains of gun-cotton should be taken and placed in 18 fluid ounces of rectified sulphuric ether, and then 2 ounces of alcohol should be added, making thus one imperial pint of the solution. The cotton, if properly made, will dissolve entirely ; but any small fibre which may be floating about should be allowed to deposit, and the clear solution poured off. To iodize the collodion. — Prepare a saturated solution of iodide of potassium in alcohol — say one ounce — and add to it as much iodide of silver, recently precipitated and well washed, as it will take up : this solution is to be added to the collodion, the quantity de- pending on the proportion of alcohol which has been used in the preparation of the col- lodion. Coating the plate. — A plate of perfectly smooth glass, free from air-bubble or stria?, should be cleaned very perfectly with a few drops of ammonia on cotton, and then wiped in a very clean cotton cloth. The plate must be he'd by the left hand perfectly horizontal, and then with the right a sufficient quantity of iodized collodion should be poured into the centre, so as to diffuse itself equally over the surface. This should be done coolly and steadily, allowing it to flow to each corner in succession, taking care that the edges are well covered ; then gently tilt the plate, that the superfluous fluid may return to the bottle from the opposite corner to that by which the plate is held. At this moment the plate should be brought into a vertical position, when the diagonal lines caused by the fluid running to the corner will fall one into the other, and give a clear flat surface. To do this neatly and cfFcctuully, some little prac- tice is necessary, as in most things ; but the operator should by no means hurry the opera- tion, but do it systematically, at the same time not being longer over it than is actuallv necessary, for collodion, being an ethereal compound, evaporates rapidly. Many operators waste their collodion by imagining it is necessary to perform this operation in great haste ; but such is not the case, for an even coating can seldom be obtained if the fluid is poured on and off again too rapidly ; it is better to do it steadily, and submit to a small loss from evaporation. If the collodion becomes too thick, thin it with the addition of a little fresh and good ether. Exciting the plate. — Previous to the last operation it is necessary to have the bath ready, which is made as follows : — Nitrate of silver -----...30 grains. Distilled water 1 ounce. Dissolve and filter. The quantity of this fluid nccessari/ to be made must depend upon the fo)in of trough to he used, whether horizontal or vertical, and also upon the size of the plate. With the vertical trough a glass dipper is provided, upon which the plate rests, preventing the necos- . sity of any handle or the fingers going into the liciuid. If, however, the glass used is a little larger than required, this is not necessary. Having then obtained one or other of these two, and filtered the liquid previously, the pfate, free from any particle of dust, &c., is to be /)«- niersed uteadilu and without hesitation ; for if a jiause should be made in any part, a line is sure to be formed, which will print in a subsefiuent part of the process. The plate being immersed in the solution must he kept there a sufficient time for the liquid to act freely upon the surface, particularly if a ncgitivo picture is to be obtained. As a general ride, it u'ill lake about two mintitrs, but (his will ran/ iiith (he trnifierati/re of the air at ihn time of operating, and the condition of the collodion. In cold weather, or, indeed, any thing below 50° F., the bath should be placed in a warm situation, or a proper decomposition is not obtained under a very long time. Above Oi>° the plate will be eert:iin to have obtained its maximum of sensii)ility by two minutes' immersion, but below this tem- perature it is better to give a little extra time. 928 PHOTOGRAPHY. To facilitate the action, let the temperature be what it mav, the plate must be lifted out of the liquid two or three times, which also assists in getting rid of the ether from the sur- face, for without this is thoroughly done, a uniform coating cannot be obtained ; but on no account should it be removed unlil the plate lias bceii immersed about half a mijiule, as marks are apt to be produced if removed sooner. The plate is now ready to receive its impression in the camera obscura. This having been done, the picture is to be developed. The development of Imar/e. — To eli'ect this, the plate must be taken again into the dark room, and with care removed from the slide to the levelling stand. It will be well to caution the operator respecting the removal of the plate. Glass, as before observed, is a bud conductor of heat ; therefore, if in taking it out, we allow it to rest on the fingers at any one spot too long, that portion will be warmed through to the face, and as this is not done until the developing solution is ready to go over, the action will be more energetic at those parts than at others, and consequently destroy tlie evenness of the picture. We should, therefore, handle the plate with care, as if it already possessed too much heat to be comfortable to the fingers, and that we must therefore get it on the stand as soon as possible. Having then got it there, we must next cover the face with the developing solution. This should be made as ibllows : — Pyrogallic acid 5 grains. Glacial acetic acid 40 minims. Distilled water 10 ounces. Dissolve and filter. Mr. Delamotte employs Pyrogallic acid -.--•-.--9 grains. Glacial acetic acid 2 drachms. Distilled water -.----..-3 ounces. Now, in developing a plate, the quantity of liquid taken must be in proportion to its size. A p'.ate measuring 5 inches by 4 will require half an ounce ; less may be used, but it is at the risk of stains ; therefore we would recommend that half an ounce of the above be measured out, into a perfecth/ clean measure^ and to this from 8 to 12 drops of a 50- grain solution of nitrate of silver be added. Pour this quickly over the surface, taking care not to hold the measure too high, and not to pour all on one spot, but having taken the measure properly in the fingers, begin at one end, and carry the hand forward ; immediately blow upon the face of the plate, which has the effect not only of diffusing it over the surface, but causes the solution to combine more ccjually with the damp surface of the plate : it also has the effect of keeping any de- posit that may form in motion, which, if allowed to settle, causes the picture to come out mottled. A piece of white paper may now be held under the plate, to observe the develop- ment of the picture : if the light of the room is adapted for viewing it in this manner, well ; if not, a light must be held below, but in either case arrangements should be made to view the plate easily whilst under the operation : a successful result depending so much upon obtaining sufficient development without carrying it too fiir. As soon as the necessary development has been olitained, the liquor must be poured off, and the surface washed with a little water, which is easily done by holding the plate over a dish, and pouring water on it ; talcing care, both in this and a subsequent part of the pro- cess, to hold the plate horizontally, and not vertically, so as to prevent the coating being torn by the force and weight of water. Protosulphate of iron, which was first introduced as a photographic agent in 1840 by Robert Hunt, may be employed instead of the pyrogallic acid with much advantage. The beautiful collodion portraits obtained by Mr. Tunny of Edinburgh are all developed by the iron salt. The following are the best proportions : — Protosulphate of iron - - - 1 ounce. Acetic acid 12 minims. Distilled water 1 pint. This is used in the same manner as the former solutions. Fixinrj of imnfie. — This is simply the removal of iodide of silver from the surface of the plate, and is effected l)y pouring over it, after it has been dipped into water, a solution of hyposulphite of soda, made of the strength of 4 ounces to a pint of water. At this point dayliglit may be admitted into the room, and, indeed, we cannot judge well of its removal without it. We then see by tilting the plate to and fro the iodide gradually dissolve away, and the different parts left more or less transparent, according to the action of light upon them. It then only remains to thoroughly wash away every trace of the hyposulphite of soda, for should any salt be left, it gi'adually destroys the picture. The plate should therefore cither be immersed with great care in a vessel of clean water ; or, what is better, water PLUMBAGO. 929 poured gently and carefully over the surface. After this it must be placed upright to dry, or held before a fire. Tke fixing proce^es. The most important part of Photography, and one to which the least attention has been paid, is the process of rendering permanent the beautiful images which have been obtained. Nearly all the fine photogiaplis with which we are now familiar are not permanent. This is deeply to be regretted, especially as there appears to be no ne- cessity for their fading away. In nearly all cases the fading of a photograph may be re- ferred to carelessness, and it is not a little startling, and certainly very annoying, to hear a very large dealer in photographic pictures declare that the finest pictures by the best pho- tographers are the first to fade. This is, no doul)t, to be accounted for by the demand which there is for their pictures, leading to a fatal rapidity in the necessary manipulatory details. There is no necessity for a photograph to fade if kept with ordinary care. It should be at all events as permanent as a sepia drawing. The hyposulphite of soda is the true fixing agent for any of the photographic processes, be they Daguerreotype, calotype, collodion, or the ordinary process for producing positive prints. It should be understood, whichever of t!ie salts of silver are employed, that by the action of the solar rays either oxide of silver or metallic silver is produced, and the unchanged chloride, iodide, or bromide can be dis- solved out by the use of the hyposulphite of soda. The photographic picture on paper, on metal, or on glass, is washed with a strong solu- tion of the hyposulphite of soda, and the silver salt employed combines with it, forming a peculiarly sweet compound, the hyposulphite of silver ; this is .soluble in water, and hence we have only to remove it by copious ablutions. The usual practice is to place the pictures in trays of water and to change the fluid frequently. In this is the danger, and to it may be traced the fading of nine-tenths of the pictures prepared on paper. Paper is a mass of linen or cotton fibre ; howsoever fine the pulp may be prepared, it is still full of capillary pores, which, by virtue of the force called capiliarity, hold with enormous force a large portion of the solid contents of the water. If we make a solution of a known strength of the hyposulphite of soda, and dip a piece of paper into it, it will be found to have lost more of the salt than belongs to the small quantity of water abstract- ed by the paper. Solid matter in excess has been withdrawn from the solution. So a pho- togaphic picture on paper holds with great tenacity one or other of the hyposulphites. By soaking there is of course a certain portion removed, but it is not possible by any system of soaking to remove it all. The picture is, however, prepared in this manner, and slowly, but surely, under the com- bined influences of the solar rays and atmospheric moisture, the metallic silver loses color, i. e., the photograph fodes. Tiie only process to be relied on demands that every picture should be treated sepa- rately. First, any number may be soaked in water, and the water changed ; by this means the excess of the hyposulphite of silver is removed. Then each picture must be taken out and placed upon a slab of porcelain or glass, and being fixed at a small angle, water should be allowed to flow freely over and off it. Beyond this, the operator should be furnished with a piece of soft sponge, and he should maintain for a long time a dabbing motion. By this mechjmical means he disturbs the solid matter held in the capillary tubes, and eventu- ally removes it. The labor thus bestowed is rewarded by the production of a permanent picture, not to be secured by any other means. In this article those processes only which have become of commercial value have been noted. The Carbon process of printing, which promises well, can scarcely be said to be as yet in a perfect state ; and for the other curious but less important processes, and for a full examination of the philosophv of the subject, see Hunt's Jicsearches on Lic/hl, 2d edition. PLATIXUM, ALLOYS OF. This metal will alloy with iron ; the alloy is malleable, and possesses much lustre. Copper and platinum in certain proportions form a brilliant alloy. Silver is much hardened by platinum ; although platinum is not soluble in nitric acid, it will, when alloyed with silver, dissolve in that acid. Some other alloys are known, but none of them are employed. PLUMBAGO, commonly called Black Lkad ; the name plumbago, and its common one, being derived from the fact of this mineral resembling lead in it? exernal appearance. In this country plumbago has been found most abundantly in Cumberland. The mountain at Borrowdale, in which the black lead is mined, is nearly 2,000 feet high, and the entrance to the mine is about 1,000 feet below its summit. This valuable mineral became so com- mon a subject of robbery about a century ago, as to have enriched, it was said, a great many persons living in the neighborhood. Even tlie guard stationed over it by the proprie- tors wiia of little avail against men infuriated with tlie love of plunder; since in those days a body of miners broke into the mine by main force, and held possession of it for a con- siderable time. The treasure was then protected by a building, consisting of four rooms upon the ground floor ; and immediately under one of them is the opening, secured by a trap-door, through Vol. III.— 59 930 PORCELAIN CLAY. which alone workmen could enter the interior of the mountain. In tliis apartnient, called the dressing-room, the miners change their ordinary clothes for their mining dress. At one time as much as £100,000 was realized from the Borrowdale mine in a year, the Cumber- land plumbago selling at 45s. per pound. This mine has not, however, been worked for many years. The la.-;t great discovery, stated to have been about £30,(i00"s worth, has been hoarded by the proprietors, a small quantity only being sold every year ; but it is now gen- erally understood to be nearly exhausted. Some few years since the Borrowdale Black Lead Mine was inspected by three experienced miners, but their report was far from en- couraging ; notwithstanding which a new company has been recently (1859) formed to work this mine. This plumbago in Borrowdale is found in " nests" in a trap rock, partially decomposed, which runs through the clay slate. In Glenstrathfarrar in Inverness, it is found in gneiss, and at Craigman in Ayrshire it occurs in coal beds which have been iormcd in coiitact with trap. In Cornwall plumbago has been discovered in small lumps in the El van courses ; and on the northern coast of that country, small pieces are picked out of the clay slate rocks, where it has been exposed by the wearing down of the cliffs. At Arendal, in Norway, it occurs with quartz. Plumbago is sometimes formed in considerable quantities in the beds of blast furnaces, especially at Cleator Moor. Plumbago occurs in Finland. Large quantities are brought from Ceylon and the East Indies. Some considerable portions are obtained from the mines of the United States. Mr. Brodie purifies plumbago by mixing it in coarse powder, in an iron vessel, with twice its own weight of commercial sulphuric acid, and seven per cent, of chlorate of pot- ash, and heats the whole over a water bath until chloric oxide ceases to be evolved. By this means the compounds of iron, lime, and alumina present, are rendered for the most part soluble, and the suljsequcnt addition of a little fluoride of sodium to the acid mixture, will decompose any silicates which may remain, and volatilize the silica present. The mass is now washed with abundance of water, dried, and heated to redness. This last operation causes the grains of the plumbago to exfoliate. The mass swells up in a surprising man- ner, and is reduced to a state of very minute division. It is then levigated, and obtained in a state of great purity, ready to be compressed by the method of Brockedon. — T. S. H. POAKE. A name amongst peltmongers for the collected waste arising in the prepara- tion of skins ; it is used for manure. PORCELAIN' CLAY. {Kaolin.) Nature has, up to a certain point, provided the arti- cle which man requires for the elaboration of the most perfect production of the potter s art. The clay — China clay, a.s it is commonly called, or kaolin, as the Chinese have it — is quarried from amidst the granitic masses of Dartmoor and of Cornwall. We are not at all satisfied with any of the theories which have been put forward to account for the formation of porcelain clay. It is commonly stated to be a decomposed granite ; this rock, as is well known, consisting of mica, quartz, and felspar, with sometimes shorl and hornblende. The felspar is supposed to have decomposed ; and, as this forms the largest portion of the mass, the granite is disintegrated by this process. We have, therefore, the mica, quartz, and the clay, forming together a soft mass, lying but a short distance below the surface, but extend- ing to a fconsiderable depth. It is quite evident that this stratum is not df posited ; had it been so, the particles constituting the mass would have arranged themselves in obedience to the law of gravity, towards which there is not the slighest attempt. But we do not know by what process the decomposition of the solid granite could have been effected to a depth from the surface of upwards of one hundred feet, and then, as it often does, suddenly to cease. This, however, is a question into which we cannot at present enter. The largest quantity of porcelain or China clay is manufactured in Cornwall, especially about St. Austell and St. Stephens; from which, in 1859, about G0,000 tons were sent away to the potteries, and for paper-making and bleaching. A spot being discovered where this substance abounds, the operation is commenced by removing the vegetable soil and substratum, called liy the workmen the oi-erlmrdni, which varies in depth f^i-om about three to ten feet. The lowest part of the ground is then select- ed, in order to secure an outlet for the water used in washing the clay. The overlurdin being removed, the clay is dug up in slopes : that is, in successive layers or courses, and each one being excavated to a greater extent than the one immediately below it, the slopes resemble a flight of irregular stairs. The depth of the china clai/ pits is various, extending from twenty feet to fifty feet. The clay when first raised has the appearance and consistence of mortar; it contains numerous grains of quartz, which are disseminated throughout in the same manner as in granite. In some parts the clay is stained of a rusty color, from the presence of veins and imbedded portions of shorl and quartz ; these are called by the workmen irced, capJe, and shell, which are carefully separated. The clay is next conveyed to the floor of the washing place, and is then ready for the first operation of the process. A heap of the clay being placed on an inclined platform, on which a little stream of water falls from the height of about six feet, the workman constantly moves it and turns it POROELAIX CLAY. 931 over with a piffc/le and shovel, by which means the whole is gradually carried down into an oblong trench beneath, which is also inclined, and which ends in a covei'cd channel that leads to the catch-pits about to be described. In the trench the giains of quartz are de- posited, but the other parts of the clay, in consequence of their greater levity, are carried away in a state of suspension. This watjr is conducted into a series of pits, each of which is about eight feet long, four in breadth and in depth, and is lined on the sides and bottom with cut nioorstone, laid in a waterproof cement. In these pits the porcelain earth is gradually deposited. In the lir.'^t pit the grosser particles collect ; and being of a mixed nature, aie always rejected at the end of each day's work by an opening provided for that purpose at the bottom of the pit. When the water has filled the first pit, it overflows into the second, and in like manner into the third ; and in these pits, particularly in the second, a deposit also takes place, which is often preserved, and is called by the workmen mica. The water, still holding in suspension the finer and purer particles of porcelain clay, next overflows into larger pits, caWed ponds:, which are of the same depth as the first pits, but about three times as long and wide. Here the clay is gradually deposited, and the clear supernatant water is from time to time dis- charged by plug-holes on one side of the pond. This process is continued until, by succes- sive accumulations, the ponds are filled. At this stage the clay i.s in the state of a thick paste ; and to complete the process it only remains to be consolidated by drying, and then it is fit for the market. This, however, is a tedious operation in our damp climate, and is effected as follows : — The moist clay is removed in hand-barrows into prtn.s, wiiich are constructed like the /re7.s and ponth, but are much larger, being about forty feet long, fifteen wide, and a foot and a half in depth. The above dimensions may not be quite correct, for I did not actually measure the pits ; they are, however, very near the truth. When the pans are nearly filled, the clay is levelled, and is then, allowed to remain undisturbed until it is nearly dry. The time required for this part of the process must depend in a great measure on the state of the weather and the senson of the year, because the pans are exposed to the air. During the winter at least eight months are necessary, whilst during the summer less than half the ti.ne is sufficient. When the clay is in a fit state, it is cut into oblong masses, and carried to the drying house — an oblong shed, the sides of which are open wooden frames, constructed in the usual way for keeping oil' the rain, but admitting the free passage of the air. The clay thus dried is next scraped perfectly clean, and is then packed up into casks, and carried to one of the adjacent ports, to be shipped for the potteries. The porcelain earth thus prepared is of a beautiful and uniform whiteness, and is perfect- ly smootii and soft to the touch. — Br. Boase\ Geologi) of Cornwall. The works at Lee Moor, on the borders of Dartmoor, being, however, far more com- plete, we have selected them as the best for our description. -Seejix/. 5G8. 568 Ileie we see a quarry of thi.s decomposed granite, shining white in the sunshine, and at tlie ))ottom of thi.s quarry are numerous workmen cni[)l()yed in filling trucks placed upon a 932 POTASH, NITRATE OF. tramway. This native material is now carried off to a house, distinguislied by the powerful water-wheel which revolves on one side of it, and here it undergoes its lirst process in manufacture. The trucks are lifted, and the contents discharged into a hopper, from which the clay falls into inclined troughs, through which a strong current of water passes, and the clay is separated fvom the large particles of quartz and mica, these being discharged over a grating, tlirongh vliich flows the water charged with the clay and the finer matter, the coarser portion sliding off the grating, and Jailing in a heap outside the building. The water Contains not only the pure clay, but the finer particles of silica, mica, shorl, or of any other matters which may be mixed with the mass. To separate these from the clay, very complete arrangements are made. Large and deep stone tanks receive the water as it comes from the mill ; in these the heavier particles settle ; and when each tank becomes full, the mica, &c., is discharged through openings in the bottom, into trucks placed to receive it on a railway, and this, the refuse material of the clay works elsewhere, is liere preserved for other uses, to be by-and-by described. The water, chai-ged with its clay, now flows slowly and quietly through a great length of stone channel, and during its progress nearly all the micaceous and other particles subside ; the water eventually flowing into very large pits, in which the clay is allowed slowly to deposit. The water enters in a thin sheet at one end, and gradually diffuses itself over the large area. The clay, in an impalpable powder, falls ^down, and perfectly clear water passes away at the other end. From the clay tanks marked A and B in the plan, the semi-fluid clay is pumped into the clay-pans, beneath which there circulate hot-water pipes, and in these the clay is finally dried. When a thickness of about eighteen inches is obtained, evaporation is promoted by the graduated artificial temperatm-e produced by the water pipes. After a little time, the clay is sufficiently hard to Ije cut out, and subjected to its final drying. The clay is cut out in squares of about eight inches, so that they form parallelograms when removed from the bed. These are then placed in heat- ed rooms, and being still further dried, are fit for the market. POTASH, XITKATE OF, KO,NO^ Syn. Nitre, Saltpetre, Priamatic nitre. {Nitrate (le potasse, Fr. ; Sa/petersaiires Kali, Germ.) For the mode of purification, see GrxpowDER. This well known and useful salt is found native in various parts of the world, more espe- cially in tropical climates. The formation of nitre in the earth appears to be much facilitated by warmth. Prejmratio7i. 1. By lixiviation of earth impregnated with the salt. The earth is heat- ed with water in tanks or tubs with false bottoms, and after sufficient digestion the solution is run off and evaporated to crystallization. The nitre procured by the first operation is exceedingly impure, and contains large quantities of chloride of potassium, and some sulphate of potash. By repeated crystallizations the salt may be obtained pure. If the crude product of the lixiviatioa contains, as is often the case, the nitrates of lime or magnesia, they may be got rid of by the addition of carbonate of potash ; the earths are pre- cipitated as carbonates, and may be filtered off, while an equivalent quantity of nitrate of pot- ash is formed and remains in solution, thus : — CaO,NO= -1- KO,CO^ = CaO,CO^ + KO,NO^ 2. The second mode of preparing nitre which we shall consider, is from nitrate of soda and chloride of potassium. On dissolving equivalent quantities of these two salts in water, and salting down, double decomposition takes place. The chloride of sodium may be removed from the hot concentrated fluid by means of shovels, while the nitrate of potash, being much more soluble in hot than in cold water, remains in solution, but crystallizes out on cooling. The decomposition takes place in accordance with the annexed equation : — XaO.XO" + KCl =: XaCl + KO,NO^ The above reaction is one of great interest and importance, inasmuch as it enables us to convert Peruvian or cubic nitre, as nitrate of soda is sometimes called, into the much more valuable salt, nitrate of potash. During the last war with Eussia it was found that large quantities of chloride of pota.ssium were exported, and found their way into that country. For some time no notice was taken, because the salt appeared too haiTnless to be declared contraband of war. Eventually it was found that it was entirely used in Russia for the purpose of affording nitrate of potash, by the process described. -It need scarcely be said that the gunpowder made through the medium of our own chloride of potassium, was em- ployed against our troops in the Crimea. 3. Nitre may of course be prepared by neutralizing nitric acid by means of carbonate of potash, or the caustic alkali. The process is evidently too expensive to be employed, except for the purpose of experimental illustration, or under other special circumstances. The formation of nitre in the earth of hot climates is probably in most cases due to the decomposition of nitrogenized organic matters. The subject of nitrification is one upon which some controversy has taken place. It is supposed by some chemists that the chief source of the nitric acid is the ammonia produced during the decay of nitrogenous matters. The presence of bases appears to have a remarkable tendency to increase the production of the acid. It has been asserted that the ammonia which is produced suffers partial oxidation, POTASH, NITRATE OF. 933 the acid formed uniting with undecomposed ammonia to form the nitrate of that alkali. On the other hand, it has been argued that the ammonia does not suffer oxidation, but that the nitrogen produced during the decay of organic matter combines, at tlie instant of its liberation with oxygen, to form nitric acid, which unites with the bases present. Nitrate of ammonia, no matter how formed, suffers double decomposition in presence of the carbo- nates of the alkaline earths, the result being the production of the nitrates of lime and magnesia. It is owing to the presence of the two latter salts in the crude liquor obtained by lixiviating nitrified earth, that the addition of carbonate of potash is so important, and causes so great an increase in the produce of nitre. It has been insisted by some observers that the presence of nitrogenous organic matters is not essential to the production of nitre. In support of this it has been sliown tliat large quantities of nitrates are often found where little or no organic matters are present. This has been explained by assuming tliat porous bodies have the power of absorbing water, oxygen, and nitrogen, and producing nitric acid from them. But it is evident that other forces exist capable of inducing the oxidation of atmospheric nitrogen. It has been experimentally demonstrated that nitric acid is produced during the discharge of atmospheric electricity. It is also probable that ozone plays an important part in the phenomena of nitrification. Perhaps the most of the chemists who have investigated the subject, have been too anxious to assign the formation of nitre to one particular cause, whereas the phenomena which have been noticed by different observes are in favor of the idea tliat several agencies are at work during the production of nitrates in the earth and in artificial nitre beds. During the time that France was fighting single-handed against the rest of Europe, great ditficulty was found in obtaining sufficient nitre for the production of the vast amount of gunpowder necessary to enable her artillery to be effectively supplied with ammunition. This led the French chemists to establish artificial nitre beds in various paits of the country. The success of the process may be judged of from the fact that they yielded 2,000 tons annually. Chemical and phi/sical jn'opertiex. — Nitre crystallizes in colorless six-sided prisms. The crj'stals are anhydrous ; large specimens, when broken, however, generally show the pres- ence of a little moisture mechanically adhering to the interstices. If wanted in fine powder, it must therefore be first coarsely bruised, and then dried, after which it may be finely pulverized and sifted, without that tendency to adhere into lumps which would other- wise be observed. By the careful application of heat, nitrate of potash may be melted without undergoing any decomposition or loss of weight. But if the heat be raised to redness it begins to de- compose, the degree to which the change takes place depending on the amount of heat and the time of exposure. By carefully heating for some time, a large quantity of nitrite of pot.ish is formed, oxj'gen gas Ijeing evolved. If the heat be raised, or the exposure to a high temperature be continued, a large quantity of nitrogen accompanies the oxygen, and the nitre becomes more and more changed, until finally, a mixture of potash with peroxide ofpot;issium is attained. If copper filings, clippings, or shreds be mixed with the nitre, the decomposition proceeds much more readily, and Wohlcr has proposed to prepare pure potash by this means. At high temperatures nitre is a potent agent of oxidation, so much so, that the diamond itself is attacked and converted into carbonic acid, which unites with the potash. It was in this manner that Smithson Tennant first showed the diamond to consist of pure carbon. Ills mode of operating was to fuse the nitre with fragments of diamond in a tube of gold. Cry.stallized boron, which is said to equal if not exceed the diamond in hardness, is not attacked by fused nitre. A very striking experiment lor the lecture table consists in pouring charcoal in powder into melted nitre retained at a red heat over a lamp. A violent deflagration takes place, and a considerable quantity of carbonate of potash js formed. The presence of the latter substance may be shown as soon as the capsule has become cold, l)y adding an acid to its contents, when a strong effervescence will take place. The oxidizing power of nitre is made use of in the arts in order to obtain bichromate of potash from chrome iron ore. Nitrate of potash is sometimes used as a source of nitric acid, but nitrate of soda is in every way more economical. This will be evident when it is considered that it takes 101 parts of nitrate of potash to yield one equivalent of dry nitric acid (.54 parts), whereas 85 [tarts of nitrate of soda yield the same amount of acid. Moreover, if nitrate of potash bo used, it is essential to employ two equivalents of sulphuric acid to decompose one etjuivalent of the salt, for if only one were used, the residue of sulphate of potash being hard, and not very readily removable by water, considerable chances would be incurred of injuring the still ; it is usual, therefore, to so adjust the proportions that the readily soluble bisulphate should be the residue. If, on the other hand, nitrate of .soda be employed, the residue in the still being sul[)hate of soda, no dillicidt.y is found in its removal. Nitrate of potash is employed in l)low-pipe experiments, in order to assist in the pro- duction of the green reaction characteri.stie of the presence of manganese. It often happens where the (juantity of manganese is exceedingly small, as in rose quartz, that the green 934 rOTASII, XlTIiATE OF. coloration with soda or platinum foil cannot be obtained ; if, however, a little nitre be add- ed, and the testin;^ be repeated, the reaction trenerally ai)pears witliuut any trouljle. Nitrate of pota^li is greatly employed in tb.e prepaiation of pyrotechnic mixtures. It ought always to be well dried and reduced to fine powder before being used. Solubility of nitre in water at various temperatures. 1 part of nitre dissolves in 13'320 parts of water at 32°*0 " 4-000 " er-o " 3-450 " 64°-4 " 1-340 " 113"-0 «• 0-424 " 206''-6 " 0-250 " 212'-0 From the above table it is evident that the solubility of nitre in water increases very rapidly with the temperature. Nitre is not unfrequently employed by the chemist for determining the percentage of sulphur in coals. For this purpose the coal, reduced to fine powder, is mixed with nitre and carbonate of soda, and projected by small portions into a silver crucible, maintained at a red heat. A platinum crucible must not be employed, as it is attacked by nitre in a state of fusion. The sulphur in the coal is converted, by the oxidi- zing agency of the nitre, into sulphuric acid ; the latter can then be converted into sulphate ol'baiyta, and the jiercentage of sulphur ascertained from its weight. Extiiiiution of the value of nitre. — A great number of processes have been devised for the determination of the percentage of puie nitre of jjotash in samples of the crude salt. All these processes are more or less incorrect, and a really accurate mode of determining tlie value of nitre his long been felt as a want by chemists. This want has only quite re- cently been supplied by Messrs. Abel and Bloxam of the Woolwich Arsenal, who have devoted much labor and skill to the subject, the importance of which, in connection with the art of war, can scarcely be over-estimated. Before detailing the new and successful process of the latter chemists, we will take a brief glance at the other methods commonly used for the purpose. The Fiench process depends upon the principle that a solution, when saturated with one salt, is still capable of dissolving a considerable quantity of saline matter differing in its nature from the hist. If, therefore, a saturated solution of nitre be poured upon pnic nitre, no more is dissolved if the temperature remains the same as it was when tlie original solution was prepai'ed. But if, on the other hand, the saturated solution of nitre be digested with an imjjure sample containing the chlorides of sodium, potassium, &c., the latter .salts will be dissolved, and the pure nitre remaining can, after proper draining, &c., be dried and weighed. The loss of weight obviou.sly represents the impurities removed. This process is subject to so many sources of error that the practical details need not be entered into. Another mode of valuing nitre consists in fusing the salt, and, after cooling, breaking the cake ; the tiiicness or coarseness and general characteis of the fracture are the means whereby the greater or loss value of the salt are ascertained. This process, which is known as the Swedish or .'>wartz's method, is far too dependent on the individual experience and dexterity of the operator to be of any value in the hands of the chemist whose attention is only now and then directed to the valiwtion of salii)etre. Moreover, although those who are in the habit of using it possess some confidence in its correctness, it is quite evident that it is impossible for such an operation to yield results of analytical accuracy. The Austiian method has also been used by some, but it is quite inadmissible as a gen- eral working process. It consists in ascertaining the temperature at which the solution crystallizes. (Jossart's method consists in determining the value of the nitre by measuring its power of oxidation. The latter is accomplished by finding the quantity of protoxide of iron which it can convert into peroxide. If to an acid solution of protosulphate of iron nitj-ic acid or a nitrate be added, the proto is converted into a persalt at the expense of a portion of the oxygen of the nitric acid, thus : — 2 (Fe0,80=) -f NO* 4- SO^" = Fe-0=, 3S0' -+-N0*. Theoretically this process is unexceptionable, ))m in practice it is liable to great errors. M. Pelouze endeavored to improve the above process by using such an excess of the proto.salt of iion that the nitre added should be able to convert only a portion of it into a per.sait. The remaining protoxide was then converted into persalt by means of a solution of peimanganate of potash of known strength. The data so obtained enabled the value of the nitre to be estimated. But even this process is liable to variations. The next process which we shall notice is that wiiich the chemists alluded to hare finally settled upon as yielding the best results. It is that of M. Gay-Lus.sae. It depends on the fact that if nitrate of potash be heated with charcoal, or, in fact, any carbonaceous matters i.i exee.ss, the nitiate is converted into carl)onate of potash, the amount of which may be accurately estimated by means of a standard solution of sulphuric acid. The chlorides wliich may be present are unacted upon by the charcoal, and do not, therefore, inlluenee iOTASH, NITRITE OF. Vi35 the result ; but if sulphates be present they are reduced by the carbon to sulphides, wliich, in consequence of being decomposed by the sulphuric acid, may cause serious errors. Fortunately the amount of sulphuric acid present in nitre is seldom sufficient to cause any great error. Any nitrate of soda present would come out in the final result as nitrate ot potash, and thus become another source of error ; in practice this is seldom likely to occur. The original process consists in weighing out 20 grammes (308-69 grains) of crude saltpetre, and mi.\ing it with 5 grammes (77-17 grains) of charcoal, and 80 grammes (1234-7 grains) of chloride of sodium. The mixture is thrown little by little into a red-hot crucible, and, when the decomposition is over, allowed to cool. The residual mass is dissolved in water, filtered, and water passed through the filter until it amounts to 200 cubic centimetres, (12-2 cubic inches.) The amount of alkali is then ascertained with a burette and standard sul- phuric acid. (See Alkalimeter.) Messrs. Abel and Bloxam have minutely and laljorious- ly studied this operation, and detected its sources of difficulty and error. Their researches have led them to employ the following modification. Twenty grains of the sample are to be well mixed' in a platinum crucible with 30 grains of finely-powdered resin, and 80 grains of pure dry common salt. The heat of a wire gauze flame is then applied, until no more vapor is given off. The crucible is then allowed to cool down a little, and 25 grains of chlorate of potash are added. A gentle heat is then applied until most of the chlorate is decomposed ; the hetit is then raised toJ>right redness for two or three minutes. The mass should be fluid, and free from floating charcoal. The mass, when cool, is removed to a funnel, and the crucible, &c., washed with boiling water. The mass is then dissolved in hot water, and the entire solution, colored by litmus, is neu- tralized with the standard acid. lu the annexed table 20 grains of pure nitre were taken for each experiment :— Exp. Nitre found. Nitre per cent. 1. 20-00 100-00 21 20 00 100-00 3; 19-91 99-85 4. 19-97 99-85 5. 20-08 100-40 6. 20-08 100-40 7. 20-08 100-40 The authors, not yet satisfied, made 53 more experiments by this method. The mean result with pure nitre was 99-7 per cent. The mean of 25 of the above experiments was 98-7 per cent. The mean of the remainder was 100-7 per cent. Subsequent experiments showed that greater accuracy might be obtained by substituting for the resin, pure ignited finely divided graphite, prepared by Professor Brodie's patented process. To perform the process 20 grains of the nitre are to be mixed with 5 grains of ignited graphite and SO grains of salt. The general process is conducted in the manner described in the operation with resin. The results are very exact, and apparently quite sufficient for all practical purpose. — C. G. W. POTASH, NITRITE OF, KO,NO^ When ordinary saltpetre, or nitrate of potash, is heated with sulphuric acid, in the cold, no special reaction becomes evident, as far as any evolution of gas is concerned ; but if, previous to the addition of the acid, the nitre be strongly fused, it will be found, as soon as the admixture takes place, that red fumes are evolved. This arises from the fact that nitrate of potash, when subjected to strong ignition, is decomposed with evolution of oxygen, the nitrate becoming gradually converted into the nitrite of potash, thus : — KO,NO' = KO,XO' -f 20. This reaction acquires great interest from the circumstance, that to its correct explana- tion was owing the commencement of the fame of the illustrious Swedish chemist Schcele. A pharmaceutist, at Ups;xla, having heated some saltpetre to redness in a crucible, hajjpen- ed, when it became cold, to pour vinegar over it, when, to his surprise, red fumes were evolved. Gahn was applied to for an explanation ; but, unable to conipreheiul the m-attter, he applied to liergmann ; but even he was as nmch in the dark as Gahn. The explanation which these eminent chemists were unable to give, was supplied by the pharmaceutist's ap- prentice, the young Scheele. Bergmann, when informed by (Jahn of Schecle's explanation, felt a strong desire to make his acquaintance, and ultimately they were introduced to each other. Nitre of potash has acquired some importance of late years, owing to the valuable propcritics, as a decomposing agent, which have been found by chemists bo reside in nitrous acid. Prepnrntion. — Nitrate of potash is to be fused at a red heat for a considerable time. When cold, the contents of the cruciljlc are to be dissolved out with boiling water, and the nitrate of potash remaining is to be removed as far as possible by crystallization. The nitrite of potash may be obtained from the mother liquor l)y evaporation and subsequent 930 PRINTING BLOCKS— ELECTRO. crvptallization. It is a neutral salt, which deliquesces on exposure to the air. If a piece of strongly-fused nitre bo put, when cold, into a solution of sulphate of copper, a very beautiful apple-green color is produced, of a tint which is seldom observed except in solu- tions containing the nitrite of that metal. — C. G. W. PRLNTIXG BLOCKS— ELECTRO. WhUe this book has been passing through the press, Mr. H. G. Collins has taken out two patents, which are likely to prove of essential service to the publishing world. By the one he is enabled to take on vulcanized caout- chouc, prepared with an equally elastic surface, an impression in transfer from anv steel or copper plate, wood block, stereotype, lithographic stoue, or, in fact, from an original drawing, if done in transfer ink on transfer paper, and increase or reduce the same to any required size. This is effected by expanding the India-rubber in one case, after it has re- ceived the impression ; and in the other, before the impression is made. In the first instance the impression is enlarged as the elastic material expands, in the other it is reduced by allowing the already expanded India-rubber to contract in its frame ; then laying the expanded or contracted copy down upon stone, and treating it after the usual manner of lithography. This prcscnt^i a vast field for adapting the plates of any work of acknowledged merit which may liave cost some hundreds or thousands of pounds, and years to produce, to the wants of the public in these days of cheap and well-illustrated literature, by bringing out the same works in a reduced size, which, but for this plan, no pul)lis]ier would think of attempting. Many plates, also, such as portraits, public buildings, or landscapes, may be enlarged and issued scparatively. This last application is particularly suitable for maps, as any one, from the size of a school atlas, may be taken and made to serve for large wall maps, without the cost of engraving the same. The rapidity with which this alteration of size can be accomplished is not among the least of its recommendations ; for an engraving that would take several months in the ordinary mode may be completed in from two to three days. This patent offers the same facilities to a vast number of the manufactures of the country, such as the lace trade, cotton printers, damask and moreen houses, potteries, paper-hangings ; in fact, to all and every one who employ art or design in their calling. It will be well to observe that the size cannot only be enlarged or diminished, as the case may be, but the pattern can be altered in form ; thus a circular design can be made into an oval, if required. Mr. Collins, by his second patent, is enabled, after these impressions are once upon the stone, to make them into electro blacks, thus reducing also the cost of printing engraved plates, which is effected in the following manner : — The impression being placed on the lithographic stone or the zinc plate — either one or the other can be employed — acid is applied to abrase to a certain extent the stone or metal over the unprotected portions ; when this is sufficiently deep a mould is taken in wax, the surface of which being prepared is subjected to the electrotype process, and thus a copper block is obtained. Mr. C. has also a provisional specification for a third patent, by which he can by the assistance of photography, produce blocks for surface printing (without the aid of the en- graver) in the course of a iev; hours. The whole of these patents are being brought into practical operation by the " Electro Printing-block Company." PRIXTIXCr M ACHIXE. An American machine, the invention of R. Hoe and Company, of New York, has within the last two years (1860) been introduced to this country. Machines of this description have been made for Tlie Tunes, and other newspaper offices, by Mr. Whitworth of Manchester. The following is Mr. Hoe's description of this machine. A horizontal cylinder of about 4-V feet in diameter is mounted on a shaft, with appro- priate bearings ; about one-fourth of the circumference of this cylinder constitutes the bed of the press, which is adapted to receive the form of types — the remainder is used as a cylin- drical distributing table. The diameter of the cylinder is less than that of the form of types, in order that the distributing portion of it may pass the impression cylinders without touch- ing. The Ink is contained in a fountain placed beneath the large cylinder, from which it is taken by a ductor roller, and transferred by a vibrating distributing roller to the cylin- drical distribution table ; the fountain roller receives a slow and continuous rotary motion, to carry up the ink from the fountain. The large cylinder being put in motion, the form of types thereon is, in succession, carried to eight corresponing horizontal impression cylinders, arranged at proper distances around it, which give the impression of eight sheets, introducing one at each impression cylinder. For each impression cylinder there are two inked rollers, which vibrate on the distributing surface while taking a supply of ink, and at the proper time pass over the form, when they again fall to the distributing surface. Each page is locked up u]3on a detached segment of the large cylinder, called by the compositors a "turtle," and this constitutes the bed and chase. The column rules run parallel with the shafts of the cylinder, so as to bind the types near the top. These wedge-shaped column rules are held down to the bed or "turtle ''by tongues, projecting at intervals along their length, and sliding in rebated grooves cut cross-wise in the face of the bed ; the space in the grooves between the column rules being filled with sliding blocks of metal, accurately fitted, the outer surface level with PIIIXTIXG AND NUMBERING CAliDS. 9:3'; the surface of the bed, the ends next the column rules being cut away underneath to receive a projection on the sides of the tongues and screws at the end and side of each page to lock them together, the tvpes are as secure on this cylinder as thev can be ou the old flat bed. In Tlie Times office there are two of those machines, one of them being a ten-cylinder machine, which is regularly employed to print 10,00i) sheets an hour, and it appears capable of printing 18,000. It is only l^y means of tlicse two American machines, and two of Ap- plegath's, all working on the diti'erent sides of the paper, that the enormous supply required every morning can be produced. The first successful application of steam, a.s a motive power, to printing presses with a platen and vertical pressure, was made in- the office where this book is being printed. Con- vinced of the superiority of the impression made by flat as compared with that of cylindrical pressure, Mr. Andrew Spottiswoode, assisted by his chief engineer, Mr. Brown, succeeded, after many experiments, in perfecting a machine whicli combines the excellence of the hand press with more than four times its speed, and a uniformity in color which can never be attained by inking by hand. The main point of the invention is the endless screw or drum which takes the carriage and type under the platen, and after the impression is taken re- turns it to its original position. PRINTING AND NUMBERING CARDS. It will be remembered in the early days of railway travelling, the ticket system then in vogue at the various stations was a positive nuisance ; as evei'y ticket before it was delivered to a passenger had to be .'^tamped, and torn out of a book — tluis causing the lo.ss of considerable time to travellers when many passengers were congregated. The first to remedy this was Mr. Edmondson, who constiuct- ed an ingenious apparatus for printing the tickets with consecutive numbers, and also dating the same. This gave great facilities for checking the accounts of the station clerks; but owing to the imperfect manner of inking, consequent ou the construction of the appara- tus, the friction to wliich the tickets were exposed, before they were delivered up, in a great manner obliterated the printing, and occasionally rendered them quite illegible. By Messrs. Church and Goddard's machine for printing, numbering, cutting, counting and pack- ing railway tickets, this diificulty is removed, and great speed is attained in manufacturing tickets, as the several operations are simultaneously performed. Pasteboard cut into strips by meaus of rollers is fed into the machine, by being laid in a trough, and brought under the prongs of a fork, (working with an intermitting movement,) which pushes the strips succes- sively forward between the first pair of a series of guide or carrying rollers. There are four pairs of rollers, placed so as to conduct the strip through the machine in a horizontal line ; and an intermittent movement is given them for the purpose of carrying the strips forward a short distance at intervals. The standards of the machine cany, at the top, a block term- ed the " pattern," as it acts the part of the press-head in the common printing machine — portions of it projecting downwards between the upper rollers of the first and second, and second and third pairs of carrying rollers, to the horizontal plane, in which the paste- board lies, so as to sustain it at those points while it receives the pressure of the printing types and numbering discs, hereafter referred to. The types to designate the nature of the ticket, as " Birmingham, First Class," are secured in a "chase," upon a metal plate or table, which also carries the numbering discs for imprinting the figures upon the cards ; and the table by a cam action is alternately raised, to bring the types and numbering discs in contact with the pasteboard, and then lowered into a suitable position, to admit of an inking roller moving over the types and numbering discs, and applying ink thereto. The table likewise carries at one end a knife, which acts in conjunction with a knife-edge, projecting downwards from the fixed head of the machine, and thereby gives the cross-cut to the strips between tlie third and fourth pairs of carrying rollers, — thus severing each into a given number of tickets. The strip of pasteboard which is fed into the machine stops on arriving at the second ]wir of carrying rollers ; and, on the ascent of the printing tal)le, the types print on that jiortion which is between the first and .second pairs of rollers. The strip then passes on to the third piir of rollers, where it stops; and, on the table again ascending, the numbering discs im- ))rint tlie proper number upon the pasteboard between the second and third pairs; the type, in the meanwhile, printing what is to be the next following ticket. On the next ascent of the table, the strip has advanced to the fourth pair of rollers ; and the knives ln-ing now brought into contact, the printed and numbered portion of the .strip is severed. The now com[)leted ticket is lastly delivered Ijy the fourth jjair of rolleis into a hollow guide piece, and conducted to a box below, provided with a piston, which, to facilitate the packing of the tickets in the box, can be adjusted to any height to i-eceive the tickets as they fall. To avoid the necessity of having to count the tickets after they are taken from the receiving box, a counting apparatus, connected with the working parts of the machine, is maile to strike a l)ell on the completion of every hundred or more tickets, so as to warn the attend- ant to remove them from the box. Tlie inking apparatus is assimilated in diaracter to self-acting inkers in ordinary ]ninting piesses ; and the numbering di.scs are worked in a m miKv verv similar to tjiose for {)aging books. 9;J8 PRINTING ROLLERS. A simple arrangement of apparatus for printing and numbering cards Iw.s been intro- duced liy Jle.s.srs. ilarrild and Sons. The types are fixed in a metal franie, winch also carries the numbering discs. This frame is mounted on a rocking shaft, and is furnished with a handle, whereby it is rocked to bring down the types and discs upon the card, to produce the impression. When the frame is raised again, the units disc is moved forward one figure, and the t}'pes are inked by a small roller, which takes its supply of ink from an inking table, that forms the top of the frame. M. Baranowski, of Paris, invented a machine foj printing and numbering tickets, and also indicating the number printed. The types and numbering discs are carried by a hori- zontal rotating shaft, upon which, near each end thereof, is a metal disc; and upon the periphery of these discs a metal frame is affixed, which carries the types and numbering tiises, and corresponds in curvature with the edge of the discs. The types for printing the inscription upon the ticket are arranged at right angles to the length of the shaft, which position admits of some lines of the inscription being printed in one color, and the remain- der in another color. In the type frame a slot or, opening is formed lengthwise of the shaft ; and behind this opening are three numbering discs, and three discs for indicating the quanti- ty of tickets numbered — all standing in the same row. The numbering discs are made with raised figures, which project through the slot, in order to print the number upon the ticket ; and on the peripheries of the registering discs (which move simultaneously with their corresponding numbering discs) the figures are engraved. The tickets to be printed and numbered are placed in a rectangular box or receiver, having at the bottom a fiat slid- ing piece, which has a recipiocating motion for the purpose of pushing the lowest ticket out of the box, through an opening in the front side thereof, beneath an elastic pressing-roller of India-rubber ; the type-frame (with the types and figures properly inked) is at the same time brought, by the rotation of its shaft, into contact with the ticket beneath the pressing roller, and as it continues its motion, it causes the ticket to move forward beneath the pressing roller, and to be properly printed and numbered. The ticket then falls from the machine ; and the type-frame, carried on by the revolution of the shaft, brings that number on the registering discs which corresponds with the number printed on the ticket, under a small opening in the case, covered with glass; whereby the number of tickets printed will be indicated. PRIXTIXG ROLLERS. Elastic inking rollers were introduced by Messrs. Donkin and Bacon. They are made of a mixture of glue and treacle, or of glue and honey ; the Ameri- can honey, it is said, being pieferred. 1 pound of good glue is softened by soaking in cold water for twelve hours, and then it is united, by means of heat, with about 2 pounds of ordinary treacle. Messrs. Hoe and Co. give the following directions for making and preserving composition rollers: — For ci/liiidir-prcss roncr!<, Cooper's No. 1. x glue is sufficient for ordinary pur- poses, and will pe found to make as durable rollers as higher priced glues. Place the glue in a bucket or pan, and cover it with water ; let it stand half an hour, or until about lialf penetrated with water, (care should be used not to let it soak too long,) then pour it off, and let it remain until it is soft. Put it in the kettle and cook it until it is thoroughly melted. If too thick, add a little water until it becomes of proper consistency. The molasses may then be added, and well mixed with the glue by frequent Ftirring. When properly prepared, the composition does not require boiling more than an hour. Too much boiling candies the molasses, and the roller consequently will be found to lose its suction much sooner. In proportioning the material, much depends upon the weather and temperature of the place in which the rollers are to be used. 8 pounds of glue to 1 gallon of sugar-house molasses, or syrup, is a very good proportion for summer, and 4 pounds of glue to 1 gallon of molasses for winter use. Hand-prcfis rollers may be made of Cooper's No. 1^^ (one and a quarter) glue, using more molasses, as they are not subject to so much hard usage as ci/lbidcr-prcsx rollers, and do not require to be as strong ; for the more molasses that can be used the better is the roller Before pouring a roller, the mould should be perfectly clean, and well oiled with a swab, but not to excess. Rollers should not be wa.shed immediately after use, but should be put away with the ink on them, as it protects the surface from the action of the air. When washed and ex- posed to the atmosphere for any length of time, they become dry and skinny. They should be wiished about half an hour f)efore using them. In cleaning a new roller, a little oil rubbed over it will loosen the ink, and it should be scraped clean with the back of a case knife. It .should be cleaned in this way for about one week, when h/e may be used. New rollers are often spoiled by washing them too soon with lye. Camphene may be substituted for oil ; but owing to its cumbustible nature it is objectionable, as accidents may ari-se from its use. PROVING MACHINE. The drawing shows a useful machine for testing the quality and power of India-rubber springs, designed by Mr. George Spencer, of the firm of Geo. Spencer and Co., and used by them for that purpose. Fiff. 575 shows an elevation, partly PURPLE DYES. 'J3'J in section, of the machine ; fg. 576 a plan of the same, a is a strong cast-iron frame, sup- ported by two cast-iron standards, b ; c is a sliding piston, working iu a hole cast in the end of frame a, one end of which impinges against the short arm of a strong cast-iron lever, d, J^ r forming one of a system of compound levers as shown, having fulcrumsat f and/, and pro- vided with a Salter's balance, 17, to register the power exerted by the spring. At the other end of frame, a, a brass nut, a, is placed in a hole in the frame, through which a square-threaded screw, s, works by means of the handle, 11, or by a long lever of wrought iron, according to the power of spring to be tested. The spring to be tested is placed between the two sliding guide plates, n, n', and a wrought-iron bolt passed through the plates, n, n', and spring, z, and passing into the hollow piston, c, for the purpose of keeping the spring in correct position, and receiving in its hollow head, M, the end of the screw, s. The action may be thus described : — The handle, II, being turned, the screw, s, advances and pushes on the plate, n', by means of the bolt- head, M. The other plate, n, rests against the piston, c, and is pressed against it by the intervening spring, z. The leverage, n, is so arranged that 1 lb. on the dial is equal to 2 cvvt. on the spring, or, in other words, is 1 in 224. Springs of a force of 20 tons can be tested by this machine safely. See Caoutchouc. PRUSSIAN BROWN. A fine deep ))rown color obtained by adding the yellow prus- siate of potash {fi'n-oprusainf.e) to a solution of sulphate of copper. PURPLE DYES. The purple dyes now oljtained liy more or less complex processes from coal tar, are so incomparably superior to any others, both in brilliancy and perma-. nence, that their production has opened up a new era in dyeing and calico-printing. The process of Mr. Perkin, the discoverer of aniline purple, is simple in principle, but the opera- tions, from the production of the coal tar to the formation of the pure purple, are so numer- ous, and require to be conducted on such a large scale, that the successful manufacture in- volves the necessity for large capital and considerable chemical skill. Mr. Perkin's process involves the following operations : — 1. Production of benzole from coal tar by fractional distillation. 2. Conversion of benzole into nitro-benzole by the action of nitric acid. 3. Conversion of nitro-benzole into aniline. 4. Production of neutral .sulphate of aniline. 5. Decomposition of sul|)hate of aniline by bichromate of potash. 6. Washing with water of the ])Tecipitate by bichromate of potash. 7. Drying of the washed precipitate. 8. Extraction of the lirown impurity contained iu the precipitate. 0. Extraction of the purple coloring matter. An outline of the process contained in Mr. Perkin's specification will be found in the article Animnk. Numerous patents have been taken out for the production of colors more or less reseni- liling Perkin's purple. J. T. Bealc and J. N. Kirkham employ l)leaching powder as the oxidizing ineiliiini. They take a saturated solution of aniline in water, and add to it acetic ariil and bleaching powder until the desired tint is ac(iiiirark. The first and second portions are mixed, strained, and treated with soda, which precipitates the alkaloids; the prccijjitate is washed and pressed, and then digesteil with dilute sulphuric acid, which di.^solves the alkaloids; this solution is evaporated and al- Inved to cool, when the sulphate of quinine crystallizes out, accompanied with some sul- 944 QUINIKE. pliatcs of quinidine and cinchonine, if the bark employed contained these latter alkaloids in any (luantity. The sulphate of (juinine thus obtained is diiod, and forms the unbleached or hospital (juinine. When the sulpluite of quinine is required (juite pure, this is treated with pure animal charcoal, and subjected to two or three further crystallizations. It will be seen that the principal points in this process are the extraction of the coloring matter by the caustic alkali and the use of pure animal charcoal in producing the perfectly white sulphate, which prevents completely the admixture of sulphate of lime with sulphate of quinine. This process yields from 80 to 90 per cent, of the quinine contained in the bark em- ployed ; and to obtain the remaining 10 or 20 per cent, the blood-red solutions formed by boil- ing the bark with the caustic alkali are treated with dilute hydrochloric acid in excess, which retains in solution any alkaloids that are present. This solution is strained and mixed with lime. The precipitate thus formed is collected, pressed, dried, and powdered. It is then digested with benzol, or any solvent which is not a solvent of lime. These various tinctures or preparations are well agitated with dilute sulphuric acid, which xtracts the quinine, &c. ; when allowed to settle, the Lmzol, oil of turpentine, or lard, whichever has been used, rises to the surface. The acid liquid is then siphoned off and evaporated, and the sulphate of quinine ol)tained from it is purified by two or three crystallizations, when it yields a salt equal to that obtained by the first process, viz. the unbleached or hos- pital sulphate of quinine. The sulphate of quinine of commerce is the neutral sulphate, and has the following composition: . 2C^"I1-^N-0',2HS0^+14 aq. When pure it occur.s as white spangles, or slender needles, which are slightly flexible, and possess a pearly lustre and an intensely bitter taste. It effloresces in the air, and loses about 12 atoms of water. {Baup.) It requires for solution, 740 parts of cold water and 30 parts of boiling water, 60 parts of alcohol at ordinary temperatures, and much less of boil- ing alcohol. Its solution in acidulated water turns the plane of polarization strongly to the left, and presents a blue tint, which is due to a peculiar refraction of the rays of light on the first surface of the solution, and is termed fuorcxccncc by Professor Stokes, who, as well as Sir John Herschel, has examined the cause of it, the latter referring it to epipolic dispersion. Heated to 212" F., sulphate of quinine becomes luminous, which is augmented by fric- tion, and the rubbed body is found to be charged with vitreous electricity, sensible to the electroscope. It fuses easily, and in that state resembles fused wax ; at a higher tempera- ture it assumes a red color, and at length becomes charred. When a solution of quinine is treated with chlorine and ammonia, it yields a bright green solution, very characteristic of cjuiuine. Besides the neutral sulphate, there exists an acid sulphate, or hisulphate, of the follow- ing composition : C'lP^N^OS 2HS0* -4- 1 6H0. It is formed by dissolving the neutral sulphate in dilute sulphuric acid, evaporating and crystallizing. It crystallizes in rectangular prisms, or silky needles. It is much more sol- uble in water than the neutral sulphate, requiring only 11 j)arts of water at ordinary tem- peratures to dis.'iolve it. The solution reddens blue litmus paper. It fuses in its water of crystallization, and at 212" F. loses 24-6 per cent, of water. (Lichifj and Baup). With sulphate of sesquioxide of iron, it forms a double salt, which crys- tallizes in octahedra resembling those of alum. An interesting compound of iodine and bisulphate of quinine has been discovered by Dr. Herapath, which crystallizes in large plates, and by reflected light presents an emerald green color and a metallic lustre, but by transmitted light appears almost colorless. The point of interest in this compound is, that its crystals have the same effect upon a ray of light as plates of tourmaline, and have even been used instead of this latter substance. Its composhion is: C^"H"XW,P,2HSO^-hl0 aq. It may be obtained by dissolving the bisulphate of quinine in concentrated acetic acid, and adding to the heated li(|uid an alcoholic solution of iodine, drop by drop. After stand- ing a few hour.s, the salt is deposited in large flat rectangular plates. Adulteration of su/pha/e of quinine. — Owing to the high price of sulphate of quinine, it is often adulterated wath various substances, as alkaline and earthy salts, boracic acid, su- gar, starch, mannite inargaric acid, salicine, sulphates of cinchonine and quinidine ; the two latter substances will be found in most of the commercial sulphate of quinine, and are not looked upon as fraudulent mixtures when present only in small quantities, arising then from the imperfect })urification of the sulphate of quinine. Sometimes, however, sulphate of cinchonine is present in large quantities, and this is effected by briskly stirring the solution from which the sulphate of quinine is crystallizing, when, although under other circum- stances the suljjhate of cinchonine would remain in solution, it will by tliis agitation be de- posited in a pulverulent form, together with the sulphate of quinine. No doubt this fraud has been prMctis'-d to a considerable extent. :JJ RAILS. 945 The inorganic substances may be easily detected by incinerating some of the suspect- ed salt, when they will be left as ash. When some of the suspected sample is dissolved in dilute sulphuric acid, the margaric acid would remain undissolved ; if we then add to the solution a slight excess of baryta water, the sulphuric acid and quinine will be precipitated ; the excess of baryta is precipitated by carbonic acid, the solution is then boiled and filtered, when the sugar, mannite, and saliciue remain in solution, and may be detected afterwards. The presence of saliciue may be detected directly in sulphate of quinine by the addition of sulphuric acid, when it becomes red if salicine be present. Starch is detected by solution of iodine, witii which it forms a deep blue compound. Boracfc acid is dissolved by alcohol, and is recognized by the green tinge given to the fiame of the ignited alcohol. For the dis- covery of cinchonine, several processes have been proposed. The one most generally adopt- ed, and perhaps the best, is that known as Liebig's process, which depends on the difference of solubility, in ether, of quinine and cinchonine. It consists in putting into a test tube 10 grains of the sulphate of quinine with 120 grains of ether, then adding 10 or 20 drops of caustic ammonia ; it is then briskly shaken. If the sulphate of quinine under examination contains no cinchonine, we obtain two layers of liquids, the one of water containing sulphate of ammonia, and the other ether holding the quinine in solution ; if the salt contained cin- chonine, this would remain suspended at the surface of the watery layer. The same process will detect quinidine also when present in quantities exceeding 10 per cent, of the sulphate of quinine ; but the great distinction between quinine and quinidine is their deportment with oxalate of ammonia, this reagent causing, in a solution of sulphate of quinine, a pre- cipitate of oxalate of quinine; whereas, the oxalate of quinidine being very soluble in water, no precipitate is formed by the addition of oxalate of ammonia to a solution of its salt. Determination of the quantity of -quinine in samples of cinchona harks. In commerce the value of a cinchona bark depends on the quantity of cry.5> 579, apian, and /.7. 580, ir^ M r^ a section of the same rail cut ^' _ — --, J '^' " i ' :_'!!^ through the middle. @ H ig Vol. III.— 60 946 EASP, MECHANICAL. These rails are made by passing bars of iron, when red hot, through rollers with indenta- tions or grooves in their peripheries, corresponding to the intended shape of the rails ; the rails thus formed present the same surface to the bearing of the wheels, and their depths being regulated according to the distance from the point of bearing, they also present the strongest form of section with the least material. See Rolling Mills. Malleable iron rails are now always employed. An objection has been urged against these rails on the ground that the weight on the wheels rolling on them expanded their upper surface, and caused it to separate in thin laminee. In many of our large stations rails may be frequently seen in this state ; layer after layer breaking off, but this may be regard- ed rather as an example of defective manufacture than any thing else. It is true. Professor Tyndal has referred to those laminating rails, as examples in proof of his hypothesis, that lamination is always due to, and is always produced by, mechanical pressure upon a body which has freedom to move laterally. Careful examination, however, convinces the writer that whenever lamination of the rail becomes evident, it can be traced to the imperfect welding together of the bars of which the rail is formed. The weight of railway bars varies according to section and length. There are some of 40 pounds per yard, and some of 80 pounds, almost every railway company employing bars of different weight. Besides flat rails, which are occasionally still used, we have bridge rails employed, which have the form of a reversed U- These have sometimes parallel sides, or, as in dovetail rails, the sides are contracted. The n-'^ils are more easily manufactured than the I-rails, the difficulty of filing the flanges not being so great as in the latter rail. Fig. 581 represents the old rail, and^^r. 582 Mr. W. H. Barlow's patent rail, which is made to form its own contin- 5S1 58.. ^ uous bearing. In section this rail somewhat resembles an in- verted V, with its ends con- siderably turned outwards. This portion forms the surface by which the rail bears upon the ballasting, the apex of the f\ being foimed with flanges in the ordinary form of rails ; and the rail, therefore, beds throughout on the ballast. It can be very easily packed up and adjusted when out of place, and all the fittings of sleepers, chairs, and keys, are done away with, nothing being rerjuired besides the rails themselves, except a cross or tic-iod at the joints, to hold them at the proper distance asunder, so as to keep the gauge of the line. RASP, MECHANICAL, is the name given by the French to an important machine much used for mashing beet-roots. See Sugar. RATTANS. The stems of the Calamus rotang, of C. ritdentnvi, and various species of palms. They are used for caning chairs, as a substitute for whalebone, for walking-sticks, and many other purposes. V<' e imported in 1858, 18,625,308 rattan canes, valued at £38,9GO. REFiNIXG GOLD AND SILVER. Since the object of this book is to treat more especially of the application of scientific processes to commercial undertakings, it would be out of place to give a detailed account of the processes ))y which gold and silver are refined, or rendered free from other metals. In the laboratory, where chemical manipulation has reached a great way to perfection, the precious metals are separated by nitric acid and other agents, but the processes are far too expensive and tedious to admit of being used upon a large scale. For the purposes of rendering gold containing foreign metals sufBciently pure for the operations of coining, Mr. Warrington has recently described a process by which fused gold is treated with black oxide of copper, with a view to oxidizing those metals wliich render gold too brittle for manufacture into coin. Mr. Warrington proposes to add to fused gold, which is found to be alloyed with tin, antimony, and arsenic, It) per cent, of its weifiht of the black oxide of copper, which, not being fusible, is capable of being stiiicd up with the fused mass of gold, just as sand may be stirred up with mercury, but witli this groat advan- tage, that the oxide of copper contains oxygen, with which it parts readily to oxidize any metal having a greater affinity for oxygen than itself The metals, once oxidized, become lighter than the fused metal, and mixing mechanically, or combining chemically with the black oxide of copper, float to the surface and are removed. In the execution of Mr. Warrington's proposition, it is imperative to use crucibles free from reducing agents, such as carbon, and it is found that half an hour is sufficient time to allow the contact of the oxide of copper with the fused gold. It has been generally stated by those supposed to be acquainted with the subject, that gold containing tin, antimony, and arsenic is so brittle as to render it wholly unfit for coin- ing. Tills requires modification, for although these metals, as well as lead, render gold so REFINING GOLD AND SILVER. 947 brittle that it will readily break between tlie fingers, yet it is not true to say that it renders gold so brittle as to be incapable of being coined. In June and Jnly, 1859, some brittle gold, to the extent of about 04,000 ounces, passed through the Mint. The bars were so brittle that they broke with the slighest blow from a hammer, but by special treatment the gold was coined into the toughest coins ever produced. It may now be stated that if the system of manufacture be changed to suit the recjuirements of the case, gold cannot be found too brittle for the purpose of coining. This is simply a matter of fact, but the ex- pense of coining brittle gold is undoubtedly very great; it is thereibre wise that Mr. War- rington's plan should be adopted for all gold containing the volatile metals or tin. Osniium- iridium does not render gold brittle. Dr. Percy and Mr. Smith have dcmonstiated tliat all metallic substances found in commerce contain traces of gold, whicli can be separated by carefully conducted chemical processes, and it is Ibund that silver is peculiaily liable to l>e in alloy with gold, and gold with silver ; hence a process of refining which shall cllbct the separation of as little as one five-hundredth part of gold from its mass of silver, is a matter of the utmost commercial importance. It is with regret that it is stated that the refineries of London are conducted with such secrecy as to render a full description of any one of them impossible, while the ignorance which will induce the proprietors of these estai)lishments to attempt such quietude is much to be pitied, for, except so far as regards details of interior arrangement, their processes are as well known and understood as it is possible for any manufacture to be. In Paris, (the London refiners are known to use the " French process,") the plan adopted is founded on the fact, that at a high temperature sulphuric acid parts with one equivalent of its o.xygen to oxidize an atom of a metal, while the atom of oxide so formed at once com- bines with another atom of sulphuric acid to form a sulphate. The atom of sulphuric acid which has parted with its atom of oxygen passes off as gaseous sulphurous acid. If mercury be boiled with sulphuric acid, (commonly called oil of vitriol,) it is found that it entirely loses its metallic existence, and assumes the form of a dense white salt. This change takes place at the expense of the sulphuric acid, and is shown Ijy the following eqtia- tion. For explanation sake, call mercury Hg, and sulphuric acid SO'; if now it is assumed that one part or atom of Hg be boiled with two parts or atoms of SO'', we have Hg + SO^ + SO^, and for elucidation we may write SO' as equal to SO'^ + 0, then we have Hg -J- + SO-* + SO^, which, under the influence of heat, become HgOSO' -:|- SO'^ a white salt. pas. If now the mind substitutes silver for mercury, and so writes Ag instead of Ilg, the whole matter will be understood. The silver is dissolved in sulphuric acid just as sugar would in water, and in this fact we have avaluable means of separating it from gold. If for a moment one imagines a mass of silver alloyed with gold to be represented by a piece of sponge filled with water and frozen, it is well known that if the mass be warm the ice is melted, and in the form of water filters from the sponge; just so, if a mass of the alloy of the precious metals be boiled in sulphuric acid, the silver is dissolved or washed away, leav- ing the gold in the form of a sponge, which, as it becomes exposed to the bubbling of the acid, is detached and falls to the bottom of the vessel in which it is boiled. If by assay the silver to be refined is found to be very rich in gold, it is better to fuse the mass with more silver, so as to produce a mass containing at least 3 of silver to 1 of gold, and this alloy, in its fluid state, should be poured into cold water, by which the falling stream is suddenly chilled, and the particles become what is technically called "granulated." The stream should fall some distance (not less than 2 feet) through the air before it reaches the water, that the coppor (if any be present) may be as much as possible oxidized, with a view to saving sulphuric acid. In all cases the alloyed metals should be granulated, because the extended surface of metal presented to the hot acid saves much time. Silver containing less than '/500 part of its weight of gold is fotmd not to pay for separa- tion, but any which contains this amount or more is treated as follows: — Vessels of platinum were formerly used, and were deemed indispensable, but experi- ment has proved that these may be safely re])laced by cast-iron vessels; in both cases the i)oilcrs or retorts aie provided with tubes passing from the top into chambers which receive the acid gases and vapors. The i)latinum vessels used by Mr. Mathison and subsequently by I^Iessrs. fJothschild for many years arc now out of use, but as .sketches of the vessels actually used cannot be ob- tained, it is deemed wi.se to give a sketch of the platinum vessels, which weigh 823--10 troy ounces, and contain, if filled to tlic neck, 8 gallons of water, a the retort or boiler; n the head, provided with a tube of platinum, n, to which.is joined at the time of >ise a long tube of lead. C is a tube terminating on the shoulder of tlie boiler, and provided with a lid, anil is of service to allow of the occasional stirring of the silver during solution, and of the addi- tion of the small (piantity of acid at the termination of tlie chemical action. The vcs.sels became much coated with gold, which was removed with dilficulty and at great risk of attacking the platinum. The sketches (fi'i/a. 583, 584, and 585) are 1 in. to a foot. 943 EEFINING GOLD AND SILVER. According to convenience and requirements, the retort or boilers may be multiplied aa to number, but about 5 or 6 would seem to be a convenient set for operations. Indepen- 583 dently of the smaller prime cost of cast-iron retorts or boilers, (now used in place of platinum,) there is the advan- tage of being able to use acid which is not free from im- purities, because the cost of the retorts is practically not worth consideration, if taken in relation to the extra price which must be paid for pure acid. Besides these facts, it is found that owing to some influence (is it chemical or catalytic V) which the iron exerts, less acid is required to be used in proportion to the precious metals than was used when platinum vessels were believed to be necessary. A charge for one boiler varies from 1 1 30 to 1 300 troy ounces of the granulated mixed j)rccious metals, and is heated with about twice or twice and a half times its weight of sul- phuric acid of sp. gr. 1'7047. The heat is gradually raised until effervescence takes place, and it is then regulated with care, while at last, the temperature is raised nearly to the boil- ing point. As in the case of mercury so in the case of silver, it is better not to rise quite to the boiling point, else sulphuric acid distils off with the escaping sulphurous acid. According to the care with which the granulating has been effected, each charge is heated from 3 to 4 hours. When the elimination of sulphurous acid ceases the operation is known to be ter- minated, and chemical examination shows that exactly equivalent quantities of sulphate of silver and sulphate of copper are formed to account for the sulphuric acid. In practice the sulphurous acid is frequently lost, although in all refineries it should be used for the recom- position of sulphuric acid. Leading from the top of the boiler or retort is an horizontal leaden tube from 8 to 10 yards long, terminating in a leaden chamber, in which sulphuric acid and sulphurous acids accumulate with some sulphate of silver mechanically carried over by the violence of the chemical action. It is found that the acid which accumulates in this leaden chamber has a sp. gr. of from l-3S04to 1-4493. The reduced strength of the acid from 1-T047 to this point is readily understood if the fact be remembered that sulphuric acid is really a com- pound of anhydrous sulphuric acid and water, and that only the anhydrous sulphuric acid is concerned, although the water performs the friendly part of leading it into action on the silver ; the action having commenced, the water is done with, and passes off with the sul- phurous acid as it is eliminated ; but independently of this cause, it is found that sulphuric acid, by boiling, parts with water, and concentrates itself, until by and by the anhydrous acid itself distils off, and when this is seen, it is at once known that the operation is carried rather too far. When the action has quite terminated, it is customary to add to each boiler or retort fiom CO to 80 troy ounces of sulphuric acid of sp. gr. 1-6656, procured from the liquor which has deposited sulphate of copper, (presently described,) then to pour the whole into a leaden Ijoiler, and boil it for a few minutes, then withdraw the fire, and allow to stand for half an hour, during which time the gold is precipitated. The object in adding this amount of sulphuric acid is to form a clear solution, that the gold may be enabled to settle to the bottom ; water could not be added, because it would probably cause an explosion by the heat evolved in its combination, and because sulphate of silver is not very soluble iu water, while it is soluble to a very large extent in hot sulphuric acid. At the end of half an hour the clear liquor, containing in solution the silver and copperas sulphates, is decant- ed and mixed with so much water as shall reduce it to a sp. gr. of from 1-2080 to 1-2605, and well stirred. Copper plates are then introduced, while the solution is kept hot or boil- ing by a jet of steam. The silver salt is decomposed by th(f copper plates, and the copper passes into solution as sulphate of copper, so that at the end of the precipitation the solution contains the copper of the original alloy, as well as the copper which has been used to precipitate the silver. The silver precipitates or falls to the bottom in a finely divided or spongy form, and it is commonly thought that the whole of the silver is thrown down when a portion of the solu- REFINING GOLD AND SILVER. 9il> tion 13 not rendered tnrbid by a solution of chloride of sodium ; but in the presence of a strongly acid solution this test is not to be relied on for minute quantities ; therefore, in some refineries, the solution is allowed to rest for days together in leaden cisterns in which copper plates are placed, so that by these means the last traces of silver are obtained. If the amount of gold be very minute, the original solution is well stirred and then allowed to settle for some time, when finely divided gold, mechanically mixed with crystals of sulphate of silver and crystals of sulphate of copper, is found at the bottom. Tiiis deposit is boiled with water, and is then transferred to a vessel in which it is kept hot, and is brought into contact witli suspended copper plates, by which the silver is rendered metallic, and fall- ing to the bottom of the vessel, mixes with the gold. The mixed precipitate of silver and gold is then dried, melted, and granulated, and treated with sulphuric acid, as in the process already described. By this extra process the gold becomes concentrated by the removal of the silver, and is then thrown down in larger and more easily collected particles. When the gold is finely divided and precipitates slowly, the following plan is sometimes adopted : — The whole precipitate containing finely-divided gold mixed with sulphate of silver, is washed well with warm water, and left to rest. The sulphate of silver is dissolved, but the gold set- tles to the bottom of the vessel, but is still mixed with a minute quantity of sulphate of silver. It is drained and placed in the retort or boiler of cast iron, and boiled with sulphu- ric acid ; this boiling is twice repeated, and at last a very diluted solution of sulphate of silver is obtained ; but by the boiling the gold has assumed a form which enables it to precipitate rapidly ; in fact, the flocculent sponge becomes a mass of dense particles, which fall readily to the bottom, are collected and well washed, to free them from silver, and are then dried ready for melting. The solution of sulphate of silver is evaporated in leaden vessels by the agency of steam until it becomes saturated, and is then allowed to stand for an hour, that all the gold may separate, and is then drawn off either by a tap placed about half an inch from the bottom of the vessel, or by a siphon, and is then treated with copper plates as already detailed. In all cases the precipitated spongy silver is carefully washed to free it from sulphate of copper, and dried by heat or by hydraulic pressure ; but if dried by pressure the masses obtained are found to contain from 8 to 10 per cent, of water, and are therefore dried by gentle heat to avoid the breaking up of the masses, from the sudden formation of steam, as well as to save the chance of destroying the pot of Picardy clay in which the silver is melt- ed when it has been dried. After melting, the silver is found to retain traces of gold, which are so minute a.s to be overlooked, since the cost of recovery would exceed the value of the gold to be recovered; but the silver is found to be alloyed with from 5 to 6 thousandths of its weight of copper, which appears to be left in the form of sulphate, notwithstanding the washings to which the silver has been subjected. It is practically impossible to wash away the last traces of sul- phate of copper. This small amount of copper is of little importance, since it amounts to but 5 parts of copper alloyed with 995 parts of silver, yet this may be removed by fusion and treatment with nitrate of potassa. During the whole process, even if copper be not present in the original mass of metal to be refined, it is to be observed that copper plates are used for precipitating the silver ; there- fore sulphate of copper is found in considerable quantities, and as this salt has a high com- mercial value as giving the base for many colors used in painting and paper-hangings, as well as for agricultural purposes, it becomes desirable to obtain this salt in a salable form. The solution is therefore evaporated to a sp. gr. of r.S804, and allowed to cool, when crys- tals deposit ; but since sulphate of cojiper deposited from strongly acid solutions is mixed with the anhydrous salt, the whole mass of crystals is redissolved in warm water, and allow- ed to stand in leaden vessels about 6 ft. long, 3 ft. deep, and 3 ft. wide, that the crystals may deposit slowly, as .slow formation produces large crystals, which are more easily collected. The sul|)hate of copper is represented by CuO,SO',5HO. Tlie mother licpiors are evaporat- ed and returned to the works, being in fact free sul[)huric acid, with a small amount of sulphate of copper in solution. The parts of the hydraulic presses which come in contact with the silver at the time of pressing, are coated with a compound of tin and lead, hardened by mixture with antimony. Cast iron is very little attacked bj' concentrated sulphuric acid, but it is necessary to avoid wrought iron in any shape, and copper vessels would of course be rapidly destroyed. The floors should be covered with lead of tolerable thickness. The melting pots used in France are made of Picardy clay, and hold from 220() to '2tiOO Troy ounces of silver. The pots cost from 4(i. to ijd. each, and if dried and used with care, very seldom crack or Ijreak. The total cost of refining silver in Paris, inclusive of the loss by melting, is stated to be IT) centimes for 32 Troy ounces; but it must be understood that the loss of silver by melt- inir is absolutely very minute, l)ecausc the (lues are swept, and the sweepings so obtained an' made to yield the silver which has been volatilized, while the pots, &c., are ground and maile to yield their absorbed silver. In the event of the mass containing much copper and little silver, it is usual to granulate 950 RHODIUM. the mas3 and roa?t the granulated particles to oxidize the copper ; the oxide of copper is tlifii dissolved out by diluted sulphuric acid, and the remaining mass of silver, with a smaller amount of copper, is treated in the ordinary way. If the gold contains platinum, it is found that it is apt to retain from 4 to 5 per cent, of silver, which must be .separated by mixing the precipitated gold with about a fourth of its weight of anhydrous sulphate of soda, (which is preferred to sulphate of potassa, on account of its greater solubility in water,) and to moisten tliis ma.ss with concentrated sulphuric acid, using about (> or 7 parts of acid to every 10 parts of sulphate of soda. The moistened mass is then heated till sulphuric acid ceases to distil off, and the heat is then raised till the whole mass melts; and by extracting the sulphate of silver and sulphate of soda the gold will be found to contain 91»-4t) parts of gold iu lOO'OO parts; but if the process be repeated, the gold is obtained of a purity of 9y"90. When the silver has been removed, the gold is fused with nitre, which oxidizes and re- moves the platinum ; but the pota.sh salt formed is found to contain gold, so that the gold and platinum are obtained from the potash salt mixed with fused nitre by the process of cupcUation, for which see Assay. — (J. F. A. KIIODIUM. The following remarks from a recent paper by Deville and Debray, "On xmiie /iropcrlies of the so-called jdatin um melafs,^^ are full of interest. These chemists prepare rhodium by fusing platinum residues with an equal weight of lead and twice its weight of litharge. When the crucible lias attained a bright red heat, and the litharge is thoroughly liquid, the crucible is shaken once or twice, and is then allowed to cool slowly. The button of lead, which contains all the metals in the residue less oxidizable than lead, is treated with nitric acid, diluted with an equal volume of water, which removes besides the lead the copper and the palladium. The insoluble powder which remains is mixed with five times its weight of binoxide of barium, weighed exactly, and is heated to redness in a clay crucible for one or two hours. After this it is first treated with water, and then with aqua regia to remove the osmic acid. When the liquor has lost all smell, sufficient sulphuric acid is add- ed to precipitate the baryta. It is then boiled, filtered, and evaporated, first adding to it a little nitric acid and then a great excess of sal ammoniac. The evaporation is carried to dryness at 212', and the residuum is washed with a concentrated solution of sal ammoniac, which removes all the rhodium. When the washings are no longer colored, the liquor is evaporated with a great excess of nitric acid, which destroys the sal ammoniac, and when only the salt of rhodium is left, the evaporation is finished in a porcelain crucible. The rho- dium salt is now moistened with hydrosulphide of ammonia, mixed with three or four times its weight of sulphur, and the crucible is heated to blight redness, after which metallic rho- dium is left in the crucible. So obtained rhodium may be considered almost pure, after it has been boiled for some time, first in aqua regia, and then in concentrated sulphuric acid. To obtain it perfectly pure it must l)e melted with four times its weight of zinc. The alloy is treated with concentrated hydrochloric acid, which dissolves most of the zinc, but leaves a crystalline matter which is really an alloy of rhodium and zinc in definite proportions. This is dissolved in arpia regia, and the solution is treated with ammonia until the precipitate first formed is redis.solved. The solution is boiled and evaporated, by which is obtained the yellow .salt, or chloride of rhodium. This is purified by repeated crystallization, and then calcined with a, little sulphur, l)y which means rhodium is procured absolutely pure. Rhodium melts less easily than platinum, so much so that the same fire which will li(|uefy ;5(H) grammes of platinum will only melt 40 or 50 grammes of rhodium. It is not volatilized, but it oxidizes on the surface like palladium. Less white and lustrous than sil- ver, it ha.s about the same appearance as aluminum. When perfectly pure it is ductile and malleal)le, at least after fusion. Its density is 12'1. The alloys of rhodium, those at least which have been examined, are true chemical com- binations, as is shown by the high temperature developed at the moment of their formation. The alloy with zinc already described resists the action of muriatic acid, but in contact with air and the odd there is soon a well-marked rose coloration which reveals an oxidation of the two metiils under the double influence of the air and acid. The alloy with tin is crys- tallized, lilack, brilli.mt, and fusible at a very high tempei'ature. RIFLE.S. RiKi.ED Okdnance and [{kvolveks. — Under the head of Fire-Arms, vol. i., in addition to the general description of the manufacture of the ordinary musket barrel and the twisted barrel, with that of gun locks of various kinds, there is an account of the mode adopted for rifling liarrels, and of the nK'tlif)ds in u.^e at the Royal Manufactory at Enfield. Beyond this, the carabine d Hffe, the Minie ritle, with the needle musket, or zundnadelge- wher of the Prussi m.s, were severally noticed; and some infoiniation given respecting the more recent Enfield rifle. So many and so inqxM-tant have been the improvements which have been introduced that it is necessary to return, somewhat more fully, to the considera- tion of this subject. Fire-arms are rifled to give rotation to the projectile round its axis of progression, in order to insure a regular and steady flight. The only practical method of doing this, iiitherto adopted, has been to make the barrel of a fire-arm of such a shape in its interior, that the projectile, while being propelled from the breach to the muzzle, may receive a rotatory, combined with a forward, motion. KIFLES. 951 Enfield Rifle. — The dimensions, &c., of the long Enfield is given in the article already referred to. The barrel of the short Enfield is only 2 ft. 9 in. in length. The material for the barrels of the arms made at the Government works is brought to tlie factory in slabs, half an inch thick, and 12 in. long by 4 in. broad. These slabs of iron are carefully forged, to insure the crossing of the fibres of the iron. They are heated, and first bent into a tubular form ; they are then heated again, and wliile white hot, passed between iron rollers, which weld the joining down the middle, and at the same time lengthen the tube nearly three inches. This heating is several times repeated, and the processes of loIIing continued until the barrel assumes the form of a rod, about 4 ft. long, having a bore down the centre about J of an inch in diameter. The muzzles are then cut off, the "butts" made up, and the process of welding on the nipple lump is begun. This operation requires much care, and it is executed with great quickness and skill by the trained workmen. The barrels pass from the smithy to the bor- ing department. The barrels are arranged horizontally, and the first-sized borer is drawn upward from the breech to the muzzle. The second boring is effected with rapidity ; but the third slowly; and after the fourth boring the barrel is finished to within the ^/looo of an inch of its proper diameter. The outside is ground down to its service size, and the barrel is straightened ; it is then tested by a proof-charge of 1 oz. of powder and 1 ball. The next step is to fit the nipple-screw, nipple, and breech-pin. The barrel is then bored for the fifth time, and it passes to the finishing shop. In lifling the Enfield, each groove is cut sepa- rately, the bit being drawn froni the muzzle to the breech. The depth of the rifling isO'5 at the muzzle, and 0'13 at the breech, and the width of each groove is Vie of an inch. After rifling the barrel is again proved, with half an ounce of powder and a single ball. It is then sighted, trimmed olf, milled, levelled, browned, gauged, and, at last, finished so per- fectly, that the steel gauge of '577 of an inch passes freely through, while that of '580 will not enter the muzzle. The system of rifling by grooves is the plan which has been generally employed, and many experiments with different numbers of grooves, some of varying depths, being deeper at the breech, and with different turns, some increasing towards the muzzle, have been tried, and thought advantageous, at various times. The Enfield rifle has three grooves, with a pitch of 6 ft. 6 in., so that the bullet receives half a turn round its axis while moving through the barrel, the length of which is 3 ft. 3 in. The bullet is cylindro-conchoidal ; it is wi'apped in paper, and made of such a diameter as to pass easily down the barrel. It re- quires very pure lead, to allow of its being properly expanded, or " upset," by the explosion, and is diiven partly against the original portions of the bore, called the lands, and partly in the form of raised ribs, is forced into the grooves, whose spiral shape gives the required rotation. The Enfield bullet is sho\^n in the annexed figure. It is conical in shape, and has its back end recessed for the insertion of a box-wood plug. Tliis plug, driven forward at the first shock of the explosion of gunpowder, expands the lead until it fills the grooves at the breech, {fig. 586.) The prime cost of a finished Enfield rifle is stated to be about £2 5.s\ ; and from 1,500 to 1,800 rifles per week are at present made at the Enfield rifle factory. W/nt worth' n R'tfle. — This fire-arm, and the principles on which it is constructed, cannot be better described than by adopting to a great extent the words of the inventor : — In the system of rilling which I have adopted, the interior of the bar- rel is hexagonal, and instead of consisting partly of non-effect- ive Icvuh, and partly of grooves, consists of elfective rifling sur- faces. The angular corners of the hexagon are always rounded, as shown in section, fig. 588, which shows a cylindrical bullet in a hexagonal barrel. The hexagonal bullet, which is pre- ferred to the cylindrical one, although either may be used, is shown in fig. 587. Supposing, however, that a bullet of a cylindrical shape is fired, when it begins to expand it is driven into the recesses of the hexagon, as shown mfig. 588. It thus adapts itself to the curves of the spiral ; and the in- clined sides of the hexagon offering no direct resistance, ex- pansion is easily elfected. With all expanding bullets proper powder must be used. In many cases this kind of bullet has failed, owing to the use of" a slowly-igniting powdt'r, which is desirable for a hard metal projectile, as it causes less strain upon the piece ; but is imsuitablc with a .soft metal expanding projectile, for which a (juickly-igniting powder is absolutely requisite to insure a complete expansion, which will fill the bore ; unless this is 952 RIFLES. done the gases rush past the bullet, between it and the barrel, and the latter becomes foul, the bullet is distorted, and the sliooting must be bad. If the projectile be made of the samo hexagonal shape, externally, as the bore of the barrel internally, that is, with a mechanical fit, metals of all degrees of hardness, from lead, or lead and tin, up to hardened steel, may be employed, and slowly-igniting powder, like that of the service, may be used. As we have already stated, the Entield rifle has one turn in C ft. 6 in. ; that is, the bullet rotates once on its axis, in passing over this space. This moderate degree of rotation, according to Mr. Whitworth, only admits of short projectiles being used, as long ones turn over on issu- ing fi'om the barrel ; and at long ranges, the short ones becomes unsteady. With the hex- agonal barrel much (luicker turns are used; and "I can fire projectiles of any required length, as, with the quickest that may be desirable, they do not 'strip.' I made a short barrel, with one turn in the inch (simply to try the effect of an extreme velocity of rotation) and found that I could fire from it mechanically-fitting projectiles, made of an alloy of lead and tin ; and with a charge of 35 grains of powder they penetrated through 7 inches of elm planks." " For an ordinary military b^rel 39 inches long, I proposed a •45-inch bore, with one turn in 20 inches, which is in my opinion, the best for this length. The rotation is suffi- cient, with a bullet of tlie requisite specific gravity, for a range of 2,000 yards. The gun responds to every increase of charge, by giving better elevation, from the service charge of 70 grains up to 120 grains; this latter charge is the largest that can be effectually con- sumed, and the recoil then becomes more than the shoulder can conveniently bear with the weight of the service musket." The advocates of the slow turn of one in 6 ft. 6 in., consider that a quick turn causes so much friction as to impede the progress of the ball to an injurious, and sometimes danger- ous, degree, and to produce loss of elevation and range ; but Mr. Whitworth's experiments show the contrary to be the case. The effect of too quick a turn, as to friction, is felt in the greatest degree when the projectile has attained its highest velocity in the barrel, that is at the muzzle, and is felt in the least degree when the projectile is beginning to move, at the breech. The great strain put upon a gun at the instant of explosion is due, not to the resistance of friction, but to the vis incrtixe of the projectile which has to be overcome. In a long barrel with an extremely quick turn, the resistance offered to the progress of the projectile as it is urged forward becomes very great at the muzzle, and although moderate charges give good results, the rifle will not respond to increased charges by giving better elevation. If the barrel be cut shorter, an increase of charge then improves the elevation. Rifled Ordnance. See Artillery. Whitworth's system of rifling is equally applicable to ordnance of all sizes, the principle of construction is simple, and the extent of bearing afforded by the rifling surfaces provides amply for the wear of the interior of the gun ; any requisite allowance for windage may be made at the same time that the projectile is kejit concentric with the bore. We have not space to enter on any examination of the rifled ord- nance manufactured by Mr. Whitworth, which is in principle the same as the rifle which we have briefly described. The extraordinary results obtained in the trials of Whitworth's guns have been so remarkable, that as a matter of curious history it appears important to preserve a statement of these trials, as made at Southport, which were witnessed by many of the most eminent authorities. Our space will not admit of our giving tables of all the experiments made ; we h.ave, therefore, cho.sen those which give the best and most interesting results. We have in each table given the distance of every shot fired in the series or group forming the particular experiment. In some cases average distances are calculated from the ascertained centre of the group of shots fired, and arc taken longitudinally and laterally. This is, in fact, apply- ing to the horizontal area in which the shots fell the same principles on which the " figure of merit" is determined on the vertical targets at the Hythe School of Musketry. This method of calculation is the most accurate, for, as the gun was always laid for the line of fire, and no alteration was made in its direction during the firing of a particular group, a certain amount of deviation would be given to all the shots by the wind. Therefore, the closer the shots lay, the better was the shooting, without regard to the general deviation from the line of fire, which might be greater or less according to the direction and force of the wind. After this digression we return again to the Rifles. A professional writer, well qualified to judge of the matter on which he wrote, has made some striking remarks on the Whit- worth rifle in the Mechanic^'' Magazine. After pointing out the small importance of a high prime cost in the case of so durable a weapon as the rifle in question, be refers to the strength of the metal used. In illustration of its great strength, this fact is quoted : Mr. Whitworth put into a rifle barrel, one inch in diameter at the breech, with a bore of 0'49inch, a leaden plug 18 incl.ei long, as tightly as it could be driven home upon the charge. It was fired with an ordinary charge of powder, and the leaden i)lug being expanded by the explosion remained in the barrel, the gases generated i)y the gunpowder all jtassing out through the touch-hole. RIFLES. 953 With such strength great durability must of necessity co-exist, unless the quick turn of the rifling should tend to its rapid deterioration. But this is not the case, Mr. Longridge's elab- orate investigations having proved that the amount of the force expended upon the rifling of the Whitworth rifle scarcely exceeds two per cent, of the total force of the powder. Table of Experiments. 3-PouNDER Gun, 9 shots fired at an eleva- tion of 3°, charge 7i oz., Feb. 22. EnDge in yards. Deviation from line of fire in yards. Average longitudinal deviation, 11^ yards ; average lateral devia- tion, f yard ; meas- ured from the centre of 9 shots fired. 1552 + 1568 , 2 1573 . i 1575 I t 1577 i 1588 1 1589 1593 1607 1 i 3-PocNDER GcN, 10 shots, at an elevation of 10°, charge 7^ oz., Feb. 23. Average longitudinal deviation, 48 yards ; average lateral devia- tion 9 7 yards from the centre of the group. 3865 n 3888 10 3871 13 3913 12 3831 13 381G 12 3717 11 3850 8 3763 n 3905 2i 3-Pou> DER GcN, 1 of 2 u", charge 6650 22 right 6614 21 6655 24 6702 17 6646 17 6704 17 6690 19 6581 19 6692 18 6645 7 6712 7 23. Average longitudinal deviation, 33 yards; average lateral devia- tion 4 yards; taken from the centre of group. 3-PocxnER GcN, 5 shots, at an elevation of 35°, charge 8i oz., Feb. 16. Range in yards. 9453 9503 9611 4965 9688 Deviation from line of fire in yards. 52 right 72 " 89 " 31 " 35 " Average longitudinal deviation, 81 yards; average lateral devia- tion 19 yards from centre of the group. 12-PorNDER GcN, 10 shots, at an eleva- tion of 5', charge 1^ lb. 2354 n right 2352 2i " 2351 3 " 2348 2 " Average longitudinal 2347 4 " deviation, 16 yards; 2343 2i " averatrc lateral devia- 2337 ileft tion from centre of 2334 2 right group, 1 yard. 2304 5 " 2288 2 " 12-PonNDER GcN, 4 shots, at an elevation of 7°, charge If lb., Feb. 21. 3098 3078 3107 3107 ileft \\ right Greatest difference in range, 29 yards ; greatest difference in width, Ij yard. SO-PorNRER GcN, 4 shots, at an elevation of 7°, charge 14 lb. 3482 3487 3498 3503 H right 6^ " 6 " 41 " Greatest difference in range, 21 yards; greatest difference in width, I5 yard. Perhaps the most remarkable testimony which has been borne to the merits of this rifle is that of General Hay, the director of musketry instruction at Ilythe. After admitting tlic superiority of the Whitworth to the Enfield in point of accuracy. General Hay said there was a peculiarity about the Whitworth small-bore rifles which no other siiniliar arms had yet produced — they not only gave greater accuracy of firing, but treble power of pen- etration. For special purposes, any description of bullet could be used, from lead to steel. The Whitworth rifle, with a bullet one-tenth of tin, penetrated 35 planks, whereas the Enfield rifle, with which a soft bullet was necessary, only p(>netratcd 12 planks. He had found tiiatat a range of 800 yards, the velocity added to tlie hardened bullet gave a power of penetration in the proportion of 17 to 4 in favor of the Wliitwortli rifle. This enormous jjenctratiou is of the highest importance in a military weapon, in filing through gabions, sandbags, and other artificial defences. Mr. Bidder, President of the Institution of Civil Engineers, says, tlie Whitworth small-bore rifl*, fired with common sporting powder, would never foul so as to render loading difficult. He had himself fired 100 rounds one day, 60 rounds the next, then 40 rounds, and so on, and left the gun witliout being cleaned for ten days, when it fired as well as it did on the first day. The words of Mr. Whitworth aa to the application of his 954 EITLES. principle to the Enfield weapon must be quoted in answer to the objections of cost, &c., uro-ed against it. " With regard to the cost of my rifled musket, which has been stated to be an impediment in the way of its adoption for the service, I may state that there would be no diliiculty in adapting the machinery and plant already in operation at Enfield, or any requi- site portion of it, for making rifles on my system. The change would not cause an increase in the manufacturing expenses; and, supposing the quality of the workmanship and the materials to remain the same, the advantages aiising from the use of my bore and turn, and hard metal projectiles, would double the efficiency of the rifle without increasing the cost." Amongst arms requiring some notice from us, the more remarkable, as involving some excellence in construction, or peculiarity in principle, are the following : — CoWs Repeating Rifle. — This weapon is constructed mainly on the principle which was introduced by Colonel Colt, in his " revolvers," to be noticed presently. The Secretary of War of the United States reports as follows on this arm, which is shown in fig. 589, and in section fig. 590. Fig. 591 is a vertical section of the revolving barrels, and fig. 592 the wiping rod. " The only conclusive test of the excellence of the arms for army purposes is to be found in the trial of them by troops in actual service. Colonel Colt's arms have undergone this test, and the result will be found in some measure, by reports of General Harney and Cap- tain Marcy, who used them in Florida against the Indians. These reports relate only to the rific, but are clear and satisfactory. * * * * _^ board of officers recently assembled to consider the best mode of arming our cavalry, made a report, showing the present appreciation of the arm by officers of the army standing deservedly high for their services, experience, and intelligence." In its internal construction this rifle differs in some respects from the pistols and early revolving rifles. The catch which causes the breech cylinder to revolve, instead of acting against ratchet teeth, and on the cylinder itself, works in teeth cut on the circumference ,of the cylinder end of the base-pin, in such a manner, that the base-pin rotates with the cylin- der itself, being locked by a small mortise in the cylinder; and the stop-bolt gears into cor- responding notches, also cut in the end of the base-pin, and thus locks it when required. This is an improvement in the arrangement of these weapons, and by a simple arrange- ment, the small spring catch, which, by means of a circular groove in the front end of the base-pin, keeps it in place, is immediately released by pressing on a small stud, and the cylinder can be instantaneously removed or replaced. Instead of the pin, which, in the pistol, is used to let the hammer down on, when carrying it, a small recess is cut between each nipple, in the cylinder itself, into which the hammer fits when let do\\ii, and makes security doubly secure. The rifle is provided with two sights; the ordinary leaf sight usually employed is also provided. The hinder sight is adjustable to suit long or varying ranges, and the front sight is that known as the bead sight, which consists of a small steel needle, with a little head upon it, like the head of an ordinary pin inclosed in a steel tube. In aiming with this sight, the eye is directed through a minute hole in the sliding piece of the hinder sight, to the small bead in the tube, which bead should cover the mark aimed at ; and this sight affords great accuracy in shooting. The wiping rod, which occupies the position usually allotted to the ramrod in muzzle loaders, is ingeniously constructed so as to admit of being lengthened. In its interior, which is hollow, slides a slight steel rod, in end of which a screw thread is cut ; on drawing out the rod, a turn or so of the hand in one direction enables this steel rod to be drawn out to a length, as nearly as possible that of the outer case, and a few turns in the contrary direction fastens it firmly in its place; thus enabling it to be used with as much facility as if it were solid. When done with, the reversal of the former motions enables the rod to be returned to its original dimensions, and it can then be returned to its place. This weapon has a real business-like serviceable appearance, and its weight varies, according to the length of the barrel, from 8 lb. to 10 lb. each, with five and six shots. Colonel Colt has introduced a new shot-gun which is adapted for being loaded alternately with shot and ball. This is adapted for the colonist, enabling him to use the gun as an ordi- nary sporting weapon for birds, &c., or for more deadly purposes. The ball for Colt's rifle is shown by figx. 594, 595. Lancasier'.s Elliptic Rife. — So called, although the elliptical rifle is very old. The bore in this rifle is slightly oblate ; the twist found by experience, to be most advantageous is one turn in 52 inches, the approved diameter of the bore "498 inches, the length of the barrel being 32 inches. An eccentricity of '01 inch in half an inch is found sufficient to make the bullet spin on its axis to the extreme verge of its flight. The length of the bullet found to answer best with these rifles is 2^ diameters in length, with a windage of four or five thousandths of an inch. Major JVuthaWs Rifie. — In the ordinary mode of grooving rifles, sharp angles are left between the groove and " land," (those parts of the smooth bore left in their original state after the process of grooving has been completed.) These create great friction with the projectile, both in loading and discharging. Major Nuthall removes these objections by rounding off the " lands " into the grooves, that is, making them a series of convex and con- 956 EIFLES. There are also General Boileau's rifle, and some others, wliich our space will not admi( of our noticing. Breicli -loading Jiijfes have been introduced, and they prove so satisfactory that the prin- ciple of breech-loading is applied to ordinary fowling pieces. Prince's breech-loader has been highly recommended. In this rifle, Ji(/. 5'JO, the barrel has attached to it a lever with a knob 596 at its end, kept in its place and locked by a little bolt attached to the bow of the guard. In order to load, the stock being firmly grasped under the right arm, the catch is released, and the knob attached to the lever is drawn to the right, and almost simultaneously pushed for- ward. The lever being firmly connected with the breech end of the barrel, the whole of the barrel is thus slipped forward in the stock, to the extent of about three inches, disclosing a steel cone, provided on either side with inclined planes, forming a segment of a screw, and locking tightly into slots at the breech end of the barrel. The cartridge is dropped into the open space at the extremity of the cone, the lever is depressed, pull backward, and then pushed into its place. The barrel and cone are thus tightly locked together, and until they are in this position the gun cannot possibly be fired. It is therefore obvious, that in strength and security this rifle is not inferior to any. At a trial at Hythe, Mr. Prince fired 120 rounds in less than eighteen minutes, showing the rapidity of loading which this weapon admits of. The rifling preferred by the inventor is a five-grooved bore rather deeply cut, the twist being three quarters of a turn in three feet. The London gunmakers have certified to the great merits of Prince's breech-loading rifle. Prince's cartridge is an ingenious invention ; it can be used either with a muzzle or with a breech-loader. The cartridge is made of gun-paper, produced in the manner described for making gun-cotton. The spark fires this with the powder, and if the paper is pure there is no ash left from its combustion. 5Ir. Prince is bringing out a new breech-loading rifle which is simpler than any yet produced. His practical experience in such matters, extend- ing over more than a quarter of a ccntur}', combined with the success he has already attained, causes any fresh arm emanating from him to be regarded w-ith considerable attention. The breech is opened by a half turn of a lever, and closed by a corresponding movement. Either common ammunition or a flask can be used in loading. The barrel is a fixture ; a chamber being attached to the breech end, so that existing muzzle-loaders may be readily converted. For cavalry a simple addition is made to the arm, so that the caps are placed on the nipple in the act of loading. lerri/s Brcech-loadiny Rifle differs from Prince's in having the barrel fixed. There is an opening at the base of the breech, which being lifted by a lever discloses a receptacle for the cartridge. Mr. Wcxtlcy Richards, Mr. Jamea Leetch., and some others have introduced breech-load- ing rifles. Of the former. Colonel Wilford says: "The weapon manufactured by Mr. \Vest- ley Richards is a perfect wonder. I saw a small carbine, weighing only 5^ lbs., fire better at" 800 yards than the long Enfield." In the rifle by Leetch the opening for the admission of the charge is in front of the cham- ber ; consequently the shooter has all the security that the solidity of the breech can impart. Revolvers or Repoaiinci Pistols. — The fame attached to Colt's revolveis, _/?osing matter ; they seem to rise from foetid cities or foetid land. Deltas have been chiefly blamed ; that of the Ganges for cholera, that of the Nile for plague, that of the Mississippi for yellow fever. Although from this view diseases would be considered as under the power of mankind to suppress, their cause seems too widely diff'used to place them under the direct control of limited communities, much less of individuals. About 1350 the whole world was thrown into violent commotion. The change may be snid to have begun in 1333, when floods, earthquakes, and sinking mountains are spoken of as occurring in China. Plague and parching drought covered much of the East : Cyrpus was nearly destroyed. In that island the earth opened and sent out a fa>tid vapor which killed many. A mist, thick and putrid, came to Italy from the East. Earthquakes occur- red all along the Mediterranean. Noxious vapors and chasms seem to have extended hundreds of miles. (IJcckrr.) Diseases from these causes are of course out of our control. Another natural source of disease is the existence of marsh land, producing malaiia. Malaria may also be produced from woody land and moist land, especially if there be many impurities. Deltas, or low lands, at the mouths of rivers, land flooded either by salt or I>y fresh water, especially if alternately by one and the other, not forgetting the great alluvial deposits, which are kept moist in hot climates. Numerous as are the cases of malaria where it is difficult to see the cause, the connection of the marshes with some febrile diseases is iM'vond any question. The fevers from this source seem in their worst states to pass into vfilow fever. This class of fevers is not epidemic, and does not travel far from its source. Tiiere are of course many cases of its being carried by the winds to a great distance, and the distance seems to depend on the amount of marshy land, or, in other words, on the extent of the poison produced. If little exist, it is dispersed before the wind travels far. Conditions of the weather may cause vegetation to putrefy instead of growing. In IPiOO, a striking example of this occurred at Modena, although other examples might be taken much nearer, if there were not such multitudes of opinions upon them. Four or five years of imusual dryness had occurred ; fruit was abundant, however, and health satisfactory. A wet winter came, chmdy and calm, without cold. This state continued through summer, with much rain. The numerous and noi.sy grnsshoppeis of Italy almost ceased, and frogs, that belong to a country of marshes, took their place. The corn had ceased to grow, and its place was supplied by fishes, so abundant was the water on the land ; whilst also organic matter was driven into the steams in unusual quantities. Vegetation was attacked with rubiffo — a rusty withered appearance — which increased in spite of all precaution ; begin- SANITARY ECONOMY. 9G9 ning with the mulberry, it attacked the corn, and then the legumens, and especially the beans. This extended' over the higher spots as well as the lower. It was melancholy to look on the fields, which, instead of being green and healtliy, were everywhere black and sootv. "The very animals returned the food which they had eaten. . . . The sheep and the silkworms perished The bees made their honey with timidity The waters became corrupt, and fevers attacked the inhabitants, chiefly tlie country people, such as Hved on the wet lands. This state produced intermittent fevers." — Bern. Ramazzini. Asain, there are causes purely artificial arising from the state of our towns in maim- facturing districts. It has been proved that diseases may be produced artificially of a kind closely resembling the great world epidemics. When persons live closely crowded together health gradually begins to fail, and loathsome diseases rapidly grow. These diseases very immeasurably, a:\d the variation seems to be as a great as the modes of decomposition of animal matter. Ai'ter a time these diseases attain virulence sufiicient to be infectious or contagious through the atmosphere. These various conditions are not perfectly understood, but even the statement of our as- certained knowledge has been most widely misunderstood by the pubhc, and sometimes even by professional men, many of whom, if they have conceived the matter clearly, have not expressed it well. There are at least three principal methods by which the air is rendered impure. 1st. by noxious gases, dust, and ashes, produced by geological, atmospheric, or artificial causes, sulphurous gas, carbonic acid, sulphuretted hydrogen, and perhaps many others. 2. Epi- demic or travelling causes to all appearance reproducing themselves as they advance, as in plague and cholera. Similar diseases produced by artificial or neglected accumulations of filth. 3. Malaria, or diseases caused by the disturbed or badly-regulated relation between tlie soil and the atmospheric conditions, whether from natural or artificial causes. It would bo difficult to include all the various evils arising from too much heat, cold, &c., &c. ; know- ing these things, we are able to a considerable extent to guide ourselves. When the disease or nuisance is caused by processes of manufacture the law sanctions interference. The judicious management of this branch of the subject is of the greatest importance to the community. There are also causes of disease relating more to the condition of the atmosphere ; for example, from the prolongation of a current of air or wind from one particular district, without due mixture ; and from conditions of moisture, and of electricity. Sanitary economy devises a method of avoiding the diseases spoken of. As to the first, those produced by geological phenomena, our chief protection lies in the choice of place : this remark may also apply to those diseases produced by atmospheric stagnation and electrical condition. AH we can do is to choose places which are known to be free from disturbances or irregularities ; when such occur, we are then able only to remove or to suffer. Such diseases are but Tittle understood. When the disease is epidemic, some trace its origin to causes which may be termed cosmic. One may be an excess of the decompos- ing agent, or by conditions of the atmosphere unfavorable to the continuation or tenacity of delicate chemical compounds. Take, as illustration, milk during a thunderstorm : this action is probably caused by a very rapid oxidation, which oxidation begins the phenomena of putrefaction. To bring such an analogy to explain the condition generally of organic matter, is legitimate, and we may either suppose the action to begin in living animals them- selves, or on substances external to them. The belief may be said to be established by a long host of great observers, that putrefying matter produces diseases under certain not very well known conditions, and that it reacts unfavorably on the health in every condition, and as a cause of instant death in concentrated forms. In Cairo, where houses are crowded with the living, and where the dead are buried with slight covering, underneath the living, there seems to be a periodic clearing out of the population by plague, reducing the number until there be enough of air to allow of healthy life. In our own prisons at one time tlie same tiling occurred, and in many of the prisons of the world impri.sonment is deatli ; such as in Turkey, China, and ])laces not civilized by modern sanitary knowledge. Prisons in Iv.irope, also might readily be mentioned as most unwholesome ; and prisons and work- hi)uses in England itself, where tlie greatest care must be taken to prevent want of clean- liness, as it produces an immediate result in disease. This is merely on a small scale what takes place on a great scale in nature. It is similar to what we every day .«ee, that man lays hold of some of the facts of nature, and under his hand they act by the same laws a.s they do in their cosmic manifestations. So in his disexses, man produces them by causing circumstances so to concur that the laws of nature act under his hand as they do when he has not interfered. Sanitary inquirers have ultimately been compelled to attribute many of the greatest effects on health to decomposition of organic matter. Almost all ages have referred to putrefaction or fermentation as an evil. The words have been used synony- mou.sly. For various opinions on this subject see Disinfectant. M. Place, in 17-1, says that in ^^'dr-' ''action a body works another lo conformity with itself. This is believed to be 970 SANITAEY ECONOMY. the case in many diseases. One erroneous opinion is very common. Gases which might be prepared in the chemist's laboratory liave been blamed as the causes of infectious diseases. Sulphuretted hydrogen and carbonic acid are spoken of as if they were infectious, and productive of fevers. Permanent cliemical compounds, gaseous or otherwise, are not capable of acting as infections. The idea of infection given is that of a body in a state of activity. But any gas, the atmospheric mixture excepted, is capable sooner or later of causing death. A true gas diffuses itself in the air, and is rapidly removed from any spot ; tu render a i)lace long unwliolesome the gas must be continuously generated at the spot. The movements of plagues are not similar to anything we know of gases ; on the contrary, we know that gases could not move in the manner that cholera and plague do. .Sulphuret- ted hydrogen is not miasma, it is poisonous ; it may destroy the constitution and produce diseases which may be deadly enough^ but the sources of it are resorted to by invalids ; this would never be the case were it a miasm. It has occasionally an internal beneficial action, and although in using it a little be taken into the lungs, this momentary breathing is not found prejudicial ; but an amount of cholera infection, such as we could perceive by the nose as readily as sulphuretted hydrogen, would no doubt be a most deadly dose ; we probably know of no such amount. The same may be said of carbonic acid and other gases. Some persons are capable of smelling the miasms of certain places — no doubt very fine senses could detect them wherever they existed ; but generally bad air may injure very im- portant organs without any effect being perceived by the senses until the evil has become very great. The chemical action is not one that the senses fully observe. Fermentation and putrefaction exhaust their powers after a short time, and cea,se ; so do infections, but not so pure gases, which act only by combining. The fermenting substances lose their power not by combination so much as a change of condition, a transformation of their parti- cles. All these actions, similar to fermentation, are connected with moist bodies : dried bodies cannot ferment, putrefy, or infect. (See Pi'trefactiox, vol. ii.) Infection, like fermentation, is most violent at an early stage, gradually spending its strength, and frequent- ly changing a portion of the substance into analogous forms. It has been argued that putrefraction cannot produce disease ; but there are no facts in nature better established than the production of disease by the presence of dead animals or vegetables, especially the first. The production of fever by crowding hospitals, barracks, and ships, is as easy as the formation of many other artificial organic actions, although no exact form of fever can be produced at will ; cases depending no doubt on time, place, climate, and constitution. The knowledge of these facts concerning zymotic diseases leads to this conclusion : in order to avoid the evil effects of decaying matter, it is necessary to have all our surroundings as clean as possible. Sanitary economy resolves itself at last chiefly into cleanliness. In- dividuals may learn pei-sonal cleanliness, but to render a town or a county clean many difficult arrangements are needed. Impurities arise from the conditions of animal life. Life is generated by the activities of certain substances which compose animals. "When the activity is over the substances are dead and unpleasant, and they pass into their former condition through a number of stages. In some of these stages the substances are gaseous, some liquid, some solid ; we may add, some in the state of vapor. Some of these sub- stances are exhalations, some excretions. Exhalations come from the surface of the whole body, but from the lungs principally. The lungs give out air with about 4, 6, and even 8 per cent, of carbonic acid in it, and the amount respired is about 380 cubic feet in 24 hours, and about 31 cubic inches per respiration, and 15 respirations per minute. The amount of air proposed as the supply for an individual varies greatly. Dr. Reid gave 30 cubic feet per minute — 1,800 feet per hour, and even 3,600. Liebig supposes 216 feet per hour. Dr. Keid gave more than was considered agreeable. Brennan supposes about 600, and calculates the following for every room per minute and per individual, the air being at 64°, and dew point at 50" : For supply to the lungs 0-83 feet To carry off insensible perspiration ... - 10-2 " For each common-sized candle 0'25 " If heated air is used for warming — For each square foot of glass in the window - - - I'D " Each window to make up for leakage .... 8"5 " Each door for the same 5 2" Eaclx 200 square feet of wall and ceiling - - - 1 " Allowing this to be excessive, the advantage of pure air is still to be urged, and it is desired most by the healthiest specimens of men. In speaking of the impure gases of the air, carbonic acid is generally referred to. This carbonic acid has been considered to be the great cause of disease in crowded local- ities, but the conclusion is contrary to our knowledge of the effects of carbonic acid when pure. There can be little doubt that there is a considerable amount of organic matter in the air of crowded places, and to that organic matter must be attributed most of the SANITARY ECONOMY. 971 evil. It may be true that 1 per cent, of carbonic acid may be observed by the senses, but this is generally tried with carbonic acid given out from the lungs. In the case of a prison in Germany, 2 per cent, of carbonic acid was found in the air. Skin diseases appeared rapidly, and deaths were excessive. But we do not know the action of the pure gas ; there must have been a large amount of corrupt matter in air which contained 2 per cent, of carbonic acid escaped from persons. It shows also great general filth. Amounts of organic matter, which are wonderfully less than even a hundredth of a per cent., are known to make the air unhealthy. In Manchester it seems to be the sulphurous acid which is chiefly felt, and that when it is less than one in a million, although it rises up in some places close to chimneys to 1, and even 4, in 100,000. It is not intended here to give statistics of disease, but it will be right to refer to the enormous amount of disease amongst miners in Cornwall. The depths being great, above 1,800 feet in some, and the temperature rising to about 100", the difficulty of working is extremely great. Candles are burnt, and the air has become so deteriorated that it contain- ed less than 18 per cent, of oxygen. The amount of carbonic acid had not risen above O'OSo per cent., which is not very high. Mr. R. Q. Couch, Sir J. Forbes, and Mr. Mack- worth, have successively reported on this subject and given some interesting details. Mr. Roberton, of Manchester, remarks on the great cleanliness of the women ; but they do not enter the mines, and their lives are longer. Consumption destroys the men rapidly in many of the deep mines.* Exhalations from the skin are abundant, both acid and oleaginous. Dr. Vogel found organic matter in the air of his class-rooms after a lecture. Dr. Angus Smith has shown that the exhalations may be traced on the walls of crowded rooms, which become coated with organic matter ; and he adds that the furniture becomes coated with a similar substance, which must be continually removed. Thus furniture and walls which are never touched in time become impure, and give out noxious exhalations when these sub- stances begin to decompose. Again, these substances are caught in our clothes and are retained there in a decided manner, on account of a peculiar faculty of retention in the fibre. This necessitates constant washing. Long custom has shown, that when retained by the cloth, a certain amount of it becomes innocent ; that is, different fibres have the power of retaining matter so firmly that it is imperceptible and incapable of acting on the air. Wool has this fiiculty to a great extent ; linen and cotton to a less extent. For this reason wool can be worn longer next the skin, remaining in reality clean. Clothes that are to be kept in good condition, if made of wool, as men's coats, cannot be washed: for this reason the custom has gradually been formed of wearing under clothing, which absorbs condcnsible substances especially, and is then washed, keeping the exterior clothing for a long time clean. As porous substances have an oxidizing power, it is probable, that if not too much organic matter is supplied, the exterior clothing, well aired, may be kept absoliltely clean, not merely by our ordinary practice of brushing and dusting, but also by oxidation, in the same way as Dr. Stenhouse has shown oxidation to take place in pores of charcoal. The instant removal of the breath and other exhalations is of great importance. This properly comes under the head of warming and ventilating. Walter Brennan, C!.E., in his " Ili.story of Warming and Ventilating," gives a remarkable amount of information. There have been many mistakes as to the effect of overcrowding ; its evils have actually been denied. The facts are very decided. Isolated houses may be crowded so much as to produce dis- eases, or they may be so badly ventilated without crowding as to have the same result. In this way persons in the country may have all the disadvantages of a crowded town. Again, a town-house well ventilated may have many of the advantages of the country, because, ulrhough the air is not of the purest, it may never be allowed to sink below the average purity of the external air. Indeed, freedom from disease is obtained in towns better in all eases than where there is a malarious atmosphere outside the town : this, of course, is well known ; and at the same time diseases from putrefaction, caused by want of space and clean- liness, are cured by leaving a town. Persons slightly exposed to the odor of water-closets in towns are frequently subjected to disease, the unoxidized air poisoning them, whilst persons working in the open air escape, although laboring amongst the excreta themselves. Again, persons living in the house are exposed to the excreta a day or two old, wliilst in the case of nightmen, it has frequently passed its worst stage when tliey apjiroach it. The stage giving off sulphuretted hydrogen is by no means the worst, peihaps one of the most innocent of the unpleasant stages, unless this gas be very strong, when it is fatal. But even in the minutest quantity this gas is hurtful to persons contiiniously exposed. The mode of removing excreta is an important point. Most inipiirers have decided against leaving them in a town, and against allowing them near a house. These conclusions are especially valuable for town hou.ses. We have in some towns whole streets of middens behind the hou.ses, and the air behind is always inferior to the front air. The process of carting refuse is also a great evil in a town. No plan removes filth so rapidly as that with * "J/tn«r's consumption,^'' as tljo disease wliicli destroys tlio miner is naincil, prevails also in the lead mines of the northern counties, which are usually shallow. — {Hd.) 972 SANITAPwY ECONOMY. water. Many people object to it, because vre have not yet learnt to make good sewers. Sewers should be tight. The Board of Health introduced small and rapid streams in the sewers, objecting to the canal-like sewers, which are as bad as cesspools, on account of the enormous amount of deposit in them, and are reservoirs of foul air from the amount of putrefaction going on within them. Many persons, not seeing this evil, have desired again to return to the no-plan of middens, not seeing what a deplorable result has been attained in Paris, where although using air-tight vessels to remove the refuse, they render most of the houses redolent of night-soil. The towns treated on the rapid removal eystem are models of cleanliness, and we do not doubt the speedy increase of the plan, especially as carried out by Robert Ilawlinson, C.E. It must be confessed, however, that the great objection to the plan is one which is not to be depised. There is too much water used ; if the water flows into the streams they are spoiled, and it is scarcely possible to put it on land. This difficulty must be met, or the plan so admirable for towns will be found de- structive to countries. There is one way of meeting it, that is, by making the liquid denser, and so having it so strong as to be a valuable manure. By a double system of drainage this might be eftected, the rain water going in a separate sewer. F. 0. Glassford proposes a water-closet which shall hold the excreta till they are mixed up to a thickish liquid with water ; he then removes it by pipes to certain reservoirs, and makes solid manure from it by sulphuric acid and evaporation, a plan which he has found to answer. Dr. Joule pro- poses large iron tanks for each block of houses, to be emptied daily, and disinfected on being emptied. All such plans must be inferior to the cleanliness caused by abundant water. We must learn to remove our filth from our towns, or they will be as unwhole- some as they once were. Nothing but abundant water can make the largest city in the world (London) the healthiest oPlarge cities. The assertion of the Board of Health is that combined works, comprising a water-pipe for the service of each house, a sink, a drain, and a waste-pipe, and a soil pan or water- closet apparatus, may be laid down and maintained in action at a cost not exceeding on the average three half-pence per week, or less than half the average expense of cleansing the cesspool for any single tenement. This seems borne out by the example of several towns under the care of engineers penetrated with the spirit which dictated the changes. To the above amount has been added water supply, which has increased the sum to threepence per week. Sewers must certainly not leak, or they must be disinfected. Dr. Angus Smith proposed long ago that they should be disinfected nearly from their sources. In other words, dis- infectants should flow through all the great sewers, and so bring them to the rivers in a state where putrefaction is impossible. The advantage of this would be great. When Mr. McDougall was showing his plan of disinfecting sewers to the Board of Works, the smell of the substance he used when he tried it in excess was perceived in the houses along the line of the sewer, showing clearly that the present sewers allow their filthy smells to go into the air of houses. lie completely destroyed the sewer smell. To prevent bad air in sewers, some persons, and amongst others some in the Board of Health, have proposed ventilation, and have thus polluted towns with the air which, after all, may be better where it was. To obviate this, they sometimes filter the air through cliareoal Ijcfore allowing it to escape. No plan will succeed but that which, by preventing putrefaction, prevents entirely the formation of foul air. At present all the lines of sewers are unclean ; they may all be cleaned by antiputrcscent Substances. If every family used them, even the smallest drains would be disinfected with univeral benefit. Of course the Thames would cease to putrefy if the larger sewers were all treated in this way. When the excretions are allowed to accumulate in a town behind the houses, as in Leeds and manv other large manufacturing towns, they must of course be periodically removed, as the amount of impure vapor is very much in proportion to the surface exposed. There is little improvement caused by slightly diminishing the solid contents. When removed, it must be taken either to deposits in the town, as at Manchester, or deposits out of the town, as at Paris. It cannot, except in small towns, be removed directly to the land, as the demand is not regular. In both cases the removal is a great grievance, and the places of deposit are unseemly, especially near Paris, at Bondy, where a great district becomes un- inhabitable. If removed by water, either the streams must be polluted, or sewers must be carried along the streams very far. If the sev.'cr matter is first disinfected in the sewers, it v.ill flow without disturbing any one; and if not so much diluted with surface matter as at present, it might be put at once on the land, without any one knowing by the smell that it differed from pure water. Since Edwin Chadwick, C.B., and Dr. Southwood Smith, whether under the name of the Board of Health, or Sanitary Commissioners, or other name, stimulated the countr}' to sanitary purposes, the supply of water and evei'V other progress relating to health has un- dergone a great change. Professor Clark first showed the advantages of soft water ; and, wherever it can be obtained, it is now used in towns. Every town which can obtain it has now a supply of water; and the supply in many is constant. ' The loss of labor to a family SANITARY ECONOMY. 973 where water is obliged to be carried from a well is sometimes equal to that of one person for at least one third of a day. And even with this loss there is an insufficient supply, which adds to the inconveniences of a household, and tiie loss of comfort and of health. As towns enlarge, and as houses become higlier, the necessity for a supply being introduced into liouses increases. In Glasgow there is a supply from Loch Katrine, 34 miles distant. The supply in Scotch houses must be taken to the highest story of the houses, on account of the system of living in flats, and because in the large towns almost every family has a water- closet and a bath. The cleaning of the surface of streets is another important point in sanitary economy. Abundance of water for this purpose would be a great advantage ; but the plan is not intro- duced here. The Whitworth sweeping machine was a good cleanser, but it was very heavy, and the cariage became expensive. Hand sweeping is still resorted to. If disinfecting agents were put into the water-carts which watered the streets, the putrefaction going on tliere in great abundance would be arrested, and the disinfected matter would flow into the sewers, which would then be free from impure air, and would run into the river in a state that would not corrupt. This was also proposed, in addition to the method alluded to of disinfecting sewers, and by the same persons. After the towns and their immediate neigh- bourhoods have been purified, it is needful to purify the land. The great sources of mala- ria are not known; but it is abundantly known that badly-drained land, especially at a high temperature, is productive of malaria; and that even at a moderate temperature malaria causes intermittent attacks. Drainage has greatly removed ague from this country ; it has cleared the land ; and the atmosphere has become brighter, because the dried land has not produced so many fogs as that which was cold and wet. The clearing of swamps was a labor of Hercules, no less valuable now. The agricultural or money value of land has, at the same time, greatly increased. Towns. — It lias been shown that a death-rate of 22 per thousand yearly prevails in Eng- 1 md, but that in large manufacturing towns it rises to 34, and in certain parts of them even to 4.3, whilst in small and healthy places it is as low as 17, and in some cases even less so. The loss of life is great, and the loss of property also. A great object of sanitary reformers his been to show that to improve health has been to improve property. There can be no doubt of it. Disease causes much loss of time and labor, and diminishes the power of a country in which it exists. We may very fairly calculate from the amount of deaths the amount of disease. To improve our health is to improve our happiness and our wealth, as well as our capacities for both. Although in some country places malaria may cause illness, and ignorance may in various ways induce most unwholesome habits, there is les.s fear of dis- ease on an average far from a town, because of the tendency of persons to live out of doors, breathing pure air, for in most places it is pure. In towns we are not only apt to be more shut up, and to have less exercise, but we are exposed to all the impurities which arise from the neighborhood of multitudes, as well as from the vapors and gases from manufactures. Many chemists have found it difficult to tell the difference between town and country air, and have denied any difference ; but it is now proved abundantly. The very rain of towns where much coal is burnt is so acid, tliat a drop falling on litmus renders it red. Blood shaken with the air of towns takes a different shade from that shaken with pure air. The air of Manchester contains about 0-0000934 of sulphurous acid, partly sulphuric, into which the first changes. Dr. Angus Smith has shown a method of measuring the amount of im- purity in the air by means of a very dilute solution of permanganate of potash. His results are obtained by filling a bottle with the air of the place, merely by pumping the air out and allowing the air around to enter. A little pei'manganate is poured into the bottle, and it is decolorized ; more is added until the color remains. By this means comparative amounts of oxidiz.ilile matter are readily measured. A pigstye required 109 measures; air from the centre of Manchester, on an average 5S ; air over the Thames, when the putrid stage had just passed, 43; London, 29; after a storm at Camden Town, 12; fields near Manches- ter, 13-7; German Ocean, 3-3; Hospice of St. Bernard, in a fog, 28; Lake of Lucerne, calm, 1-1. When sulphurous acid and sulphuretted hydrogen are present, the action is instantaneous: when organic matters only are present, the result is obtaincii more slowly. The dilferenco between town and country air is remarkable. The author hopes to make the experiment suitable for daily use in hospitals. The bottle used contains about KH) cubic inch(!s; the solution of i)ermanganate is graduated by a standard solution of oxalic acid, of which 1,000 grains contain 1 of anhydrous oxalic acid. 5 grains of this solution decompose 600 grains of the solution of permanganate. To prevent impurities in the air of towns is extremely difficult. Manufactures must not be crippled; certain noxious operations are not allowed, and complaints well substantiated against any olfensive works compel their removal. The method of ab.soibing noxious gases of some kinds is now becoming usual. The coke towers for ab.sorbing muriatic acid began a great change in. this respect. They have l)een used for sulphuric acid itself, nitrous fumes, suljihurous acid, sulphuretted hydrogen, Sec. In manufacturing towns there is little sul- phuretted hydrogen — it is decomposed rapidly by the sulphurous acid. A mode of absorb- 974 SANITARY ECONOMY. ing this latter acid from coal smoke would be a great blessing to all. But this would not remove all the evil ; coals send out black soot in such abundance that the whole of a town is darkened, every thing clean is made impure, and the people find that cleaning is a hope- less task. This might readily be burnt, but even then we have other difficulties. Ashes rise up in great amount, and fall do^Ti again in a perpetual shower of dust. It is these solid matters as well as the gases which render our towns unwholesome. If the smoke could be washed it would remove all these evils, but the loss of a draught to the fire is then a conse- quence not yet practically overcome. When coals are burnt with abundance of lime, no sulphur is given off", but the use of this cannot become general. We are very much in want of a more economical and wholesome method of obtaining from coals the power which is in them. Mr. Spence, of Manchester, proposes to connect all the furnaces of the city with the sew- ers, and thereby to burn the gases and to ventilate the sewers at the same time. He be- lieves that one chimney will ventilate readily 500 houses, including the house drains and sewers also. > The following advantages to be derived from the drainage of suburban land have been mentioned by the Board of Health : — 1. The removal of that excess of moisture which pre- vents the permeation of the soil by air, and obstructs the free assimilation of nourishing matter by the plants. 2. Facilitating the absorption of manure by the soil, and so diminish- ing its loss by surface evaporation, and being washed away by heavy rains. 3. Preventing the lowering of the temperature and the chilling of the vegetation, which diminishes the effect of solar warmth, not on the suface only, but at the depth occupied by the roots of plants. 4. Removing obstructions to the free working of the land, arising from the surface being at certain times, from excess of moisture, too soft to be worked upon, and liable to be poched by cattle. 5. Preventing injuries to cattle or stock, corresponding to the effects produced on human beings by marsh miasm, chills and colds, inducing a general low state of health, and in extreme cases the rot or typhus. 6. Dimiminishing damp at the foundations of houses, cattle sheds, and farm steadings, which cause their decay and dilapidation, as well as discomfort and disease to inmates and cattle. The Board of Health, in its excessive desire to remove all refuse by water, has often ex- aggerated the evils of every other aid to cleanliness. Water is unquestionably the best, but it cannot always be obtained. In some climates it is not to be found in abundance, and in some weather it is only to be had by the use of heat. When the cold is great there is no fear of putrefaction or putrid gases ; in warm places, or even in temperate, the use of disin- fectants before removing the putiid matter is much to be desired. The Board of Health has not feared to send putrid matter into a river, believing it better there than in the town ; it desires the water to be put instantly on the land, and to be disinfected by the land. It is well known that the process of doing this is often offensive. It is also known that large quantities of this matter cannot be disposed of at all times. It has been said that if the liquid were diminished by the rain-fall, it might be manageable. There is another method of diminishing its amount. At Carlisle it was found that the water was almost pure at certain hoXirs of the day, and at all hours of the night. By allowing the more impure only to run into the sewers, the quantity not only becomes managealile, but the quality becomes more valualjle. This is an important point, but one which will probably be less apparent in such a place as London, where the changes occurring from hour to hour cannot be so great as in smaller places. In Carlisle the sewage is deodorized and used on the meadows, and a great problem seems there and elsewhere to have begun its solution. Sanitary economy has proceeded chiefly under the impression that the pollution of the air is the evil most to be dreaded. That this idea is correct there are very many proofs; but that there are numerous other evils affecting our large towns, it is unwise to deny. Polluted air causes damp and close cellars, and unvcntilated garrets and other rooms, to be unwholesome, as well as all rooms without proper openings, without chimney.s, and with- out opening sashes to the windows. In a word, polluted air rises from close places and dir- ty places; want of light, too, is an evil under which all living creatures suffer. Great and crowded towns are subject most to all these evils, but in them also the habits of the people come into consideration. In many of the manufacturing towns the people obtain much larger wages than in the country places, but their houses are badly furnished, and their clothes, for every-day at least, are extremely filthy, whilst their love of pleasure is excess- ive. It is commonly supposed that the love of pleasure exists among the rich, but it is un- questionably one of the greatest evils oppressinr/ the poor in all large towns, because their cultivation of mind has not kept pace with their knowledge of the external appliances of civilization. A deficient intellectual and moral condition are the great causes both of poverty and bad health, for both go together in almost exact proportions. It must never be expected that pure air alone can make men healthy. The mind, as well as the body, must be freed from irregularities. Abimdant wages, which are equal to facilities of health, have rendered our working classes inferior in some cases, both in body and in mind, because they have not SEWING MACHINES. 975 Lad education to resist indulgence. These classes will often contrast badly with a poor but cleanly ruial population, cahn in mind, without a desire for excitement. Tlie subject is here only slightly touched, it needs a volume : sanitary economy, or the metliod by which man best adapts his place of abode to the conditions of external nature, must ever be a study of the most absorbing interest. — R. A. S. SCOL'KIXG. This art is tiiat which is employed for removing grease spots, &c., from clothes and furniture, which require skill beyond that of the laundry. It is divided into two distinct branches, viz., Frencli and English cleaning. We will first give an outline of English cleaning, although the other (French) has no more to do with the French than the English, except in name ; and that is kept because many people would not fancy the things were done properly if done by an English process. Gentlemen's clothes, such as trowsers, coats, &c., are treated in the following manner. They are stretched on a board, and the spots of grease, &e., first taken out by rubbing the spots well with a brush and cold strong soap liquor ; they are then done all over with the same, but the grease spots are done first, because they require more rubbing, of course, than the other parts, and when all the substance was wet they would not be so easily distin- guished. After treatment with the strong soap li(iuor,' the soap is worked by a weaker soap liquor; the articles are then well washed off with warm water, and treated with ammonia, {if 0!ack,) solution of common salt, or dilute acid, according to circumstances. They are then drained, beaten out with a little size, pressed and dried. Ladies'' articles of dress, as shawls, and woollen dresses. — The spots are first removed by rubbing them on the board with very strong soap liquor; they are then put into a strong soap liquor, and well worked about in it ; then taken out and treated with a weaker soap liquor, to work out the soap, &c. ; rinsed with warm and cold water alternately ; treated with solution of common salt or very weak acid, to maintain the colors. They are starched, if necessary, and ironed. Woollen dresses that are taken to pieces are calendered instead of ironing. Silk dresses, &c., are always taken to pieces, and each piece done separately, and as quickly as possible. If there are any spots of grease, they are taken out first, as above mentioned. Each piece, after the spots are removed, is immediately placed in a strong soap liquor, and well worked about in it, and then into a thinner soap liquor; well washed out with cold water, and treated with solution of common salt, or very weak acid, or both, as required ; each piece is then neatly folded and wrung separately, again folded smoothly and placed in dry sheets, and pressed, so as to remove all dampness from them ; they are then put into a frame, a little size or sugar and water used to stilFen and glaze ; lastly, dried while on the frame by a charcoal fire. Furniture, as curtains, i. This last sul)stance, though very soluble in alkaline menstrua, is not, however, susceptible, like fiits, of being transformed into an acid, and will not, of course, saponify or form a proper soap by itself. The more caustic the alkali the less con- sistence has the lesinous compound which is made with it. The employ of caustic alkalies, however, is not necessary with it, since it dissolves readily in aqueous solutions of carbon- ated alkalies ; but even with carbonate of soda it forms only a viscid mass, owing to its great affinity for water, so that even after having been artificially dried in an oven, and thus ren- dered to a great extent hard, the mass deliquesces again spontaneously by exposure, and returns to the soft state. The drying oils, such as those of linseed and poppy, produce the softest soaps. We said that, by boiling fats or oils with an aqueous solution of potash or of soda, a so- lution of soap was produced. The object of the soap-maker is to obtain the soap thus pro- duced in a solid form, which is done by boiling the soapy mass so as to evajjorate the excess of water to such a point that the soap may separate from the concentrated liquor and float oil tiie surface thereof in a melted state, or by an admixture of common salt, soap being in- soluble in lyes of a certain strength of degree of concentration, and in solutions of common salts of a certain strength, the glycerine remaining, of course, in solution in the liquor be- low the separated soap. Such is the theory of soap-making; but the viodus operandi fol- lowed by practical soap-makers will be described piesently. On the Continent olive oil, mixed with about one-fifth of rape oil, is principally used in making hard soap. This addition of rape oil is always lesorted to, because olive oil alone yields a soap so h ird and so compact that it dissolves only with difficulty and slowly in water, which is not the case with rape oil and other oils of a similar nature, that is to say, with oils which become thick and viscid by exposure, and which on that account are called drying oils ; experience having taught that the oils which dry the soonest by exposure, yield with soda a .softer soap than that made with oils which, like olive oil, remain limpid for a long period under the influence of the air. The admixture of rape oil has, therefore, the efFect of modifying the degree of hardness of the soap, and, therefore, of promoting its solubility. In England tallow is used instead of olive oil, the soap resulting from its treatment with soda is known under the name of curd sonp^ and is remarkable for the extreme difficulty with which it dissolves in water. The small white cubic, waxy, stubborn masses, which un- til a few years were generally met with on the washing-stand of bedrooms in hotels, and which for an indefinite period pa.>vsed on from traveller to traveller, each in turn unsuccess- fully attempting, by various devices and cunning immersions in water, to coax it into a lath- er, is curd son f>. Rape or linseed oil, added in eeitain proportions to tallow, would modify this extreme hardness and difficult solubility; but it is now the general practice to qualify the tallow with cocoa-nut oil — an oil, which, converted into soap, has the property of absorb- ing incriMlible quantities of water, so that the soap into the manufacture of which it has en- tered lathers immeiliately. Cocoa-nut oil, however, acfjuires l>y saponification a most disa- gvoealjle odor, (due to the formation of caprylic acid,) which it imparts to all the soaps in the manufacture of which it enters — an odor which peisists in sjjite of any perfume which may be added to ma-k it. The admixture of one-fourth or one-fifth of resin with tallow, in the process of saponifi- cation, mollifies also the hardness and considerably increases the solubility of curd soap, and this, in fact, constitutes the best yellow sonp. I .«aid that soap was more or less hard in proportion as the melting point of the fats em- ploved in its manufacture was higlier or lower. There are certain fatty substances, techni- cally called weak goods, such as kitchen fat, bone fat, horse oil, &c., which could hardly be SOAP. 98-6 used alone, still less with resin, the soap which they yield being too soft, and melting or dissolving awaj- too rapidly in the washing-tub. This led me to think, that if a means could be devised of artificially hardening soap, a larger class of oleaginous and fatty substances could be rendered available, at any rate to a greater extent than they hitherto had been, and that, by thus extending the resources of the soap boiler, he should be enabled to pro- duce a good and useful soap from the cheapest materials, and thus convert soaps of little commercial value into useful and economical products. In making experiments with this view, I found that the introduction of a small quantity of melted crystals or sulphate of soda into the soap answered the purpose admirably, and that the salt, in recrystallizing, imparted to the soap, which otherwise would have been soft, a desirable hardness, and prevented its being wa.sted in the tub. The use of sulphate of soda acts, therefore, inversely, like the addition of rape oil, or linseed oil, or of resin to tal- low, in the manufacture of soap. This process, which I patented in 1841, has been, since the removal of the uuties on soap, extensively employed by soap-makers, and continues to be highly approved of by the public. 3fantif act lire of mottled soap. — Soda which contains sulphurets is preferred for making the mottled or marbled soap, whereas the desulphuretted soda makes the best white curd soap. Mottling is usually given in the London soap-works, by introducing into the nearly finished soap in the pan a certain quantity of the strong lye of crude soda, through the rose spout of a watering-can. The dense sulphuretted liquor, in descending through the pasty mass, causes the marbled appearance. In France a small quantity of solution of sulphate of iron is added during the boiling of the soap, or rather with the first service of the lyes. The alkali seizes the acid of the sulphate, and sets the protoxide of iron free to mingle with the paste, to absorb more or less oxygen, and to produce thereby a variety of tints. A por- tion of oxide combines also with the stearine to form a metallic soap. When the oxide passes into the- red state, it gives the tint called manteaii Isabellc. As soon as the inottlcr has broken the paste, and made it pervious in all directions, he ceases to push his rake from right to left, but only plunges it perpendicularly till he reaches the lye ; then he raises it suddenly in a vertical line, making it act like the stroke of a piston in a pump, whereby he lifts some of the lye, and spreads it over the surface of the paste. In its subsequent descent through the numerous fissures and channels on its way to the bottom of the pan, the color- ed lye impregnates the soapy particles in various forms and degrees, whence a varied mar- bling results. , The best and most esteemed soap on the Continent is that known mider the name of Marseilles soap, and it ditfers from the English mottled soap by a diflerent disposition of the mottling, which in that soap is granitic instead of being streaky. It has also an agreeable odor, somewhat resembling that of the violet, whereas the English mottled soap, generally made of very coarse kitchen and bone fat, has an odor which reminds one of the fat em- ployed. The best English mottled soap in which tallow is employed, has no unpleasant smell, and if bleached palm oil has been used it acquires an agreeable odor, analogous to that of the Marseilles soap, which is made of olive oil alone, or mixed with rape or other grain or seed oil, which, however, seldom exceeds 10 per cent. ; for otherwise it would not have the due proportion of blue to the white, which is characteristic of soap made of genuine olive oil, the motthng becoming more closely granular when an undue proportion of grain has been used, a sign of depreciation which the dealers are perfectly well acciuainted with, and of which they at once avail themselves, to compel the maker to reduce his price. Pelouze and Fremy, in their Traite de chimie ffenerale, give the following reliable obser- vations : — " The best olive oil for the use of the soap-maker is Provence oil ; that of Aix comes next ; it is cheaper, but the same weight of it yields less soap than the other, and the latter has then a slight lemon yellow tinge. The oil from Calabre contains less margarine, and yields a softer soap. "Two kinds of soda ash are used in Marseilles, the soft soda (sonde douce) and the salt- ed soda (sonde salec), which contain a large quantity of common salt. " To prepare the lye, the soft soda previously reduced into small lumps is mixed with 12 per cent, of slaked lime, and shovelled up into tanks of masonry of about 2 cul)ic yards' capacity, called barquieux, and the exhaustion of the mass with water gives lyes of various degrees of strength. "The lye marking 12° is used for the first treatment, or cmputarjc of the oil, which is then submitted to a second and third treatment with a lye marking 15' or 20", the object of which is to close the grains of the emulsive m iss in process of saponification, (scrrcr Vem- pdtar/e.) The operation requires about twenty-four hours. During all the time of that op- eration a workman is constantly agitating the boiling mixture of tlie oil and lye by means of a long rake or c.utch, called rdble. The enifxllage is generally practised in large conical tanks of ma.sonry terminated at bottom by a copper pan, and capable of containing 12 or lo tons of made soap, and the operation proceeds so much tiie more rapidly, as the soda ho employed contains less common salt ; wherefore soft soda lye (sonde douce) must be iiued at I'le beginning, as we said. 984 SOAP. " The next operation is that called relargarjc, the object of which is to separate the larpe quantity of water which has been used to facilitate the empdtage. This separation of the water, or rdargage, is effected by means of salted soda, (that is to say, of soda a.'^h, contain- ing a good deal of common salt), of which as much is dissolved in water as will make a lye marking 20° or 25°. This salted lye is then gradually poured by a workman on the surface t;f the saponifying goods in the copper, while another workman is diffusing it in the mass by etirrijig the whole with a rake or crutch. " The immediate effect of the salt thus added is to separate from the soapy mass the water in which it was dissolved, and which gave it a homogeneous and syrupy appearance, and to coagulate it, the soap being thereby curded or coagulated, and converted into a mul- titude of granules floating among the excess of water in which they were dissolved, and which the salt has separated. The whole being then left at rest for two or three hours, in order to give the grains of soap time to rise and agglomerate at the surface, a workman proceeds to the epinage, an operation which consists in withdrawing the hquid portion by removing a wooden plug placed at the lower part of the boiler." In this country the epinage is generally performed by means of an iron pump plunging through the soap down to the pan at the bottom of the copper. This xpent h/e, in well-conducted factories, retains but little alkali, and is generally thrown away; but as it contains a rather large quantity of salt, which, in PVance, is an ex- pensive article, it might be, and is sometimes, kept and used for preparing fresh lyes. After the first epinage, the soap is treated twice again with salt lye, followed of course by two (-phiages ; but as the salt lye used in these two operations is not exhausted, it is al- ways kept for preparing fresh lyes. The cleansing, that is to say, the removing of the soap into the frames, takes place on the third day, at which time the operation called madrage is performed. J'or that purpose a plank is thrown across the boiler or copper, and two or three men standing on it, and therefore over the soapy mass in the copper, proceed to stir it up for two or three hours, by means of long crutches, which they alternately move up and down through it, the object being to keep the grains of soap well diffused through the liquid, weak lyes marking only 8° or 10", or ordinary water, as the case may be, being sprinkled from time to time into the mas.s, until the grains of soap have reabsorbed a sufficient quantity of water and have swol- len to such a size as to have a specitie gravity very little greater than that of the liquid among which they float about. A skilful workman knows by the appearance of the soap grains whether he should use alkaline lyes or simply water, and this is indeed a most im- portant point in the manufacture of Marseilles soap, for upon it the success of the operation depends in a commercial point of view, that is to say, all things being equal in other re- spects, a profit or loss on the batch of soap made will ensue. In effect, if too much water has been added the soap will lose either the whole, or too great a portion of its mottling ; that is to say, the result will be either a dingy white curd, or a soap in which the white por- tions will predominate to too great an extent over the blue streaks, a circumstance which so far deteriorates the market value, the buyer shrewdly suspecting then that he would pay for water the price of soap. If, on the contrary, a sufficient quantity of water has not been added, the soap grains remaining hard and dry, will form more or less friable, thereby caus- in"- also a deterioration of price, the buyer knowing that such soap, by crumbling into small pieces every time he has to cut it with his knife in selling it to his customers, will consider- ably reduce his profit, or perhaps even entail a positive loss to him. In the best conditions, that is to say, by employing the best Gallipoii oil for the purpose of producing Marseilles soap of fir.st quality, 100 cwt. of olive oil yield 175 cwt. of mottled soap ; liy using mixtures of^ olive and rape or other seed oils, the yield of soap is reduced to 170, or even less; in either case the yield is reduced by 5 or G per cent., when old or fermented is employed instead of new good oil. The manufacturing expenses are calculated at Marseilles at the rate of 17f. 25c. (nearly 13s. and lOj.) per ioo kilogrammes of fatty matter employed, wliich require 72 kilo- grammes of soda for their saponification. Mottled soap has a marbled, or streaky appearance, that is to say, it has veins of a blu- ish color, and resembling granite in their disposition or arrangement. The size and num- ber of these veins or speckles, and the proportion which they bear to the white ground of the soap, depend not only on the more or less rapid cooling of the soap after it has been cleansed, that is, transferred from the copper to the frame, but also on the quality and kind of the fat, grease, or oil employed, and on the manner in which it has been treated in the copper. A soap which has not been sufficiently boiled at the last stage of the manufacture is always tender. The blue or slate-color of the streaks or veins of mottled soap is due to the presence of an alumino-ferruginous soap interposed in the mass, and frequently also to that of sulphurct of iron, which is produced by the reaction of the alkaline sulphurcts contained in the soda lye upon the iron, derived from the soda ash itself, and from the iron pans and other utensils employed in the manufacture, or which is even purposely intro- duced in the state of solution of proiosulphate of iron. This introduction, however, is never SOAP. 985 resorted to, I believe, in this country. The veins or streaks disappear from the surface to the centre by keeping, because the iron becomes gradually peroxidized. A well-manul'ac- tured mottled soap cannot contain more tlian 33, 34, or at most 36 per cent, of water, whereas genuine curd soap contains 45, and yellow soap at least 52 per cent, of water, and sametimes considerably more than that. It is evident, in edect, tliat the mottling being due to the presence of sulphuret of iron held in the state jiaitly of deuiisolution and of suspen- sion, the addition of water would cause the coloring substances to subside, and a white, mii- colored, or fitted soap would be tlie result. This addition of water, technically called ///('/w.f/, is made when tlie object of tlic manufacturer is to ol)tain a inueolored soap, whetlier it be curd or yeUow soap. Afti^r fi (tin ff, the soap contains, therefore, an additional ciuantity of water, which sometimes amounts to 55 per cent. : the interest of tlie consumer would, tliere- fore, cle irly be to buy mottled soap in preference to yellow or white soap ; the mottling, when not artificially imitated, being a sure criterion of genuineness ; for the adihtion of water, or of any other substance, would, as was just said, infallibly destroy the mottling. To yellow or curd soap, on the contrary, incredible quantities of water may Ije added. I have known five pails of water (15 gallons) added to a frame (10 cwt.) of already _/?//?(/ soap, so that tlie soap, by this treatment, contained upwaids of 60 per cent, of water, to which common s ilt liaJ previously been added. The proportion of water in fitted soap has also been augmented, in some instances, by boiling the soap in high-pressure boilers before c^ea;i.?- i7iff. As cocoa-nut oil has the property of absorbing one-third more water, v/hen made into soap, than any other material, its consumption by the soap-maker has, within the last fifteen or twenty years, augmented to an extraordinary extent ; and, moreover, the patent taken in 1857 by Messrs. Blake and Maxwell, of Liverpool, for the invention of Mr. Kottula, which we shall describe presently, has, I believe, increased the demand for that species of oil in a notable degree. We said that the mottling, inasmuch as it was indicative of genu- ineness, was the more economical soap to buy ; unfortunately mottled soap has the draw- back of not being so readily soluble as yellow .soap, and the goods washed with it are more difficult to rinse; but the process patented by Messrs. Blake and Maxwell enabling the man- ufacturer to manufacture with coa-nut od a soap to which the mottling is artificially impart- ed, by means of ultramarine, black or brown oxide of manganese, in such a perfect manner as almost to defy detection, mottling has thus ceased to be a safe outward sign of genuineness, as far as regards the article which it pretends to represent. That description of soap, how- ever, has specific qualities; it is almost perfectly neutral, and it will not bear more than a definite proportion of water ; so that, although it contains more of that rupiid than ordi- nary mottled soap, — more than a certain fixed quantity cannot be forced into it; so that it also forms a standard soap, like the ordinary mottled, although that standard is different from, and inferior to, the latter. The process in question ia briefly as follows: — Take 80 cwt. of palm oil, made into soap in the usual way, with two changes of lye, grained with strong lye, or lye in the usual manner, but so that the lye leaves the curd perfectly free ; pump the spent lye away, and add 32 cwt. of cocoa-nut oil, GO cwt. of lye, at 20" of Beaume's areometer, and then gradually 14 cwt. of lye, at 14° Beaume. Boil until the whole mass is well saponified. Put now from 6 to 7 lbs. of ultramarine in water, or weak lye, stir the whole well, and pour it into the soap through the rose of a watering pot ; boil the whole tor aljout half an hour, or an hour, and cleanse it in the ordinary wooden iVames, or in iron frames surrounded by matting, or other covering, so that the soap may not cool too rapidly: the above proportions will yield 212 cwt. of soap, with a beautiful blue mottle. Determination of water and iin/niritics. — Besides water, soap is often adulterated by gelatine, forming a soap sometimes called " bone soap," which is made by adding to the soap a solution of disintegrated bones, sinews, skins, hoofs, sprats, and other cheap fish in strong caustic soda; also by dextrine, potato starch, pumice stone, silica, plaster, clay, salt, chalk, carbonate of soda, &c., and by fats of another or inferior kind than those from which they are represented to have been made. These impurities or superadded materials and their amount may be ascertained in the following manner : Estimation of the (juimtity of water: — Take about 1,000 grains of th(> soap under cxam- inition, cut into small and thin slices, not only from the outside, which is always drier, but from the interior of the sam[)le, so that the whole may represent a fair average ; mix the mass well together, and of this weigh accurately 100 grains; place it in an oven heated to a temperature of 212° Fahr., until it is quite dry, weighing it occasionally until no loss or diminution of weight is observed, the ditference between the original and the last weight, the loss, indicates, of course, the proportion of water. The loss of water in mottled soap and in soft soap should not be more than 30 to 35 per cent. ; in white or yellow soap from 3G to at most 50 per cent. If the soap is sulphated, the amount of sulphate craployed may bo determined by taking 200 grains of the sample, dissolving it in a cap.sule with boiling water, adding to the boiling solution as much hydrochloric acid as is necessary to render the li(|uid strongly acid, aiul therefore to decompose the soap entirely, throwing the whole in a filter jircviously wetted with water, adding to the filtrate an excess of chloride of barium, washing thoroughly the 986 SOAP. ■white precipitate so produced, igniting and weighing it ; every grain of sulphate of barytes thus obtained represents r467 grain of crystallized sulphate of soda. If the soap contains clay, chalk, silica, dextrine, fecula, pumice stone, ochre, plaster, salt, gelatine, &c., dissolve 100 grains of the sr^pected soap in alcohol, with the help of a gentle heat; the alcohol will dissolve the soap and leave all these impurities in an insoluble etate. Good mottled soap should not leave more than 1 per cent, of insoluble matter, and ■white or yellow soap still less. All soap to which earthy or siliceous matter has been added is opaque instead of transparent at the edges, as is the case with all genuine or fitted and sulphated soap. The drier the soap, the more transparent it is. Bone soap, or glue soap, is recognized by its unpleasant odor of glue and its dark color, its want of transparency at the edges ; that made with the fat of the intestines of animals has a disgusting odor oifteces. When uncombined silica has been added to soap, its presence may be readily detected by dissolving the suspected soap in alcohol, as before, when the silica will be left in an in- soluble state ; but if the silica is in the state of silicate of soda or of potash, it is necessary to proceed as follows: — dissolve a given weight of the suspected soap in boiling water, anil decompose it by the gradual addition of moderately dilute hydrochloric acid, until the liquor is strongly acid ; boil the whole for one or two minutes longer and allow it to cool in order that the fatty acids having separated and become hard, may be removed. Evaporate the acid liquor to perfect dryness, and the perfectly dry mass treated with boiling water will leave an insoluble residue which may be identified as silica by its grittiuess, which is recog- nized by rubbing it in the capsule with a glass rod. This white residue should then be col- lected on a filter, washed, dried, ignited, and weighed. The proportion of alkali (potash or soda) may be easily determined by an alkalimetrical assay as follows : — Take 100 grains of the soap under examination, and dissolve them in about 2,000 grains of boiling water ; should any insoluble matter be left, decant carefully the superincumbent solution and test it with dilute sulphuric acid of the proper strength, exactly as described in the article on alkalimetry. The proportion of alkali contained in soap may also be ascertained by incinerating a given weight of soap in an iron or platinum spoon, crucible, or capsule, treating the residue with water, filtering and submitting the filtrate to an alkalimetrical assay. This method, however, cannot be resorted to when the soap contains sulphates of alkalies, because the ignition would convert such salts, or a portion thereof, into carbonates of alkali, ■which by saturating a portion of the test-sulphuric acid would give an inaccurate result. The proportion of oil or fat in soap is ascertained by adding 100 grains of pure white wax free from water to the soap solution, after supersaturation with an acid, and heating the whole until the wax has become perfectly liquid, and has become perfectly incorporated with the oil or fat which has separated by the treatment with an acid. The •«hole is then allowed to cool, and the waxy cake obtained is removed, heated in a weighed crucible or capsule to a temperature of about 220"^ Fahr. in order to expel all the water, after which the whole is weighed ; the increase above 100 grains (the original weight of the wax) indi- cates, of course, the quantity of grease, fat, or oil contained in the soap. This addition of wax is necessary only when the fatty matter of the soap is too liquid to solidify well in cool- ing. Good soap ordinarily contains from 6 to 8 per cent, of soda; from 60 to 70 per cent, of fatty acids and rosin, and from 30 to 35 per cent, of water. The nature of the fat of which a given sample of soap has been made is more difficult to detect; yet, by saturating the aqueous solution of the mass under examination with an acid, collecting the fatty acids which then float on the surface, and observing their point of fusion, the operator at any rate will be thus enabled to ascertain whether the soap under examina- tion is identical with the sample from which it may have been purchased, and whether it was made from tallow, or from oil, &c. When the fatty acids which have been isolated and collected by decomposing the soap with an acid, as already described, are heated in a small capsule the odor evolved is often characteristic, or at least generally gives a clue to the nature of the fats or oils from which the soap has been made. This odor is often sufficiently perceptible at the moment when the aqueous solution of the soap is decomposed by the acid poured in. Cocoa-nut oil can always be detected when in proportions at all available to the soap-maker by tasting the poap, that is to say, by leaving the tongue in contact with the soap for a few moments, when a peculiar, very disagreeable and bitter flavor will become more or less perceptible. Properly made soap should dissolve completely in pure water; if a film or oily matter is seen to float on the surface, it is a proof that all the fat is not saponified. Another test ia that the fatty or oily acid separated by decomposing the aqueous solution of the soap by hydrochloric acid, should be entireli/ soluble in alcohol. Soft soaps, as we said, are combinations of fats or oils with potash, or rather are solu- tions of a potash soap, in a lye of potash, and they therefore always contain a great excess of alkali, and a more or less considerable proportion of water; they contain also a certain SODA, CARBONATE OF. mi quantity of chloridea, of sulphates, and all the glycerine which the saponifying process haa set free. Soft soap in this country is generally used for fulling, and for cleansing and scour- ing woollen stuffs. In Belgium, Holland, and Germany it is used also for washing linen, which thereby acquires an almost intolerable odor of fish oil, which no amount of perfume can mask, fish oil being generally employed in the manufacture of that description of soap. The most esteemed soft soap, however, is that made from hempseed oil, which imparts to the soap a greenish color, but this much-prized color is generally or very often artificially given to the soap made of other oil, which soap has a yellow color, by means of a little indigo finely pulverized and previously boiled for some time in water. For further particu- lars on the manufacture of soap, see vol. ii. SODA, CARBONATE OF (Kohlcusaurcs'tiatron, Germ.) Manufacture. — The manufac- ture divides itself into three branches : — 1. The conversion of sea salt, or chloride of sodium, into sulphate of soda. 2. The decomposition of this sulphate into crude soda, called black balls by the workmen. 3. The purification of these balls, either into a dry white soda ash ov into crystals. Preparation of Sulphate of Soda. — The decomposition of the common salt {chloride of sodium) by sulphuric acid is effected in furnaces, of vi\nc\ijig. 608 is a drawing, taken from Dr. ?^ Miller's Elements of Chemistry, a, the smaller of the two compartments which compose the furnace, is of cast iron ; into this [t.he decomposei') from five to six hundred weight of common salt are introduced, and an equal weight of sulphuric acid, of specific gravity 1"6, is gradually mixed with it; a gentle heat being applied to the outside, enormous volumes of hydrochloric acid gas are disengaged, and pass off by the flue d to the condensing towers e and F; these towers are filled with fragments of broken coke, or stone, over which a continu- ous stream of water is caused to trickle slowly from h h. A steady current of air is drawn through the furna(?e and condensing towers, )>y connecting the first tower with the second, as represented at cf, and the second tower with the main chimney, k, of the works. In the first bed of the furnace, about half of the common salt is decomposed, leaving a mixture of bisulphate of soda and common salt, which requires a greater heat for the expulsion of this latter portion of hydrochloric acid ; for this purpose it is pushed through a door into the roaster^ or .second division, b, of the furnace. The. 'Wflction in the first bed of the furnace is represented as follows : — 2NaCl + 2HS0^ = NaSO* IISO« + HCl 4- NaCI Common salt. Sulphuric acid. Common salt. By the higher temperature obtained in this second part of the furnace, the bisulphate of soda reacts on the undecomposed chloride of sodium, yielding neutral sulphate of soda and a fresh quantity of hydrochloric acid. NaSO\ USD' + NaCl = 2(NaS0^) -f IICl Bisulphate of soda. Common salt. Sulpliato of soda. Hydrochloric acid. The hydrochloric acid gas, as it is liberated from n, passes off through the flue, ccomes anhydrous. It is generally found in commerce i 1 large crystals, which l)elong to the oblique prismatic system. It is strongly alkaline, and acts on the skin, dissolving the outside cuticle. It is largely used in the manufacture of soap, gla.ss, &c., and is generally too well known to recpiire much description. The .soda trade made great progress in 1850, as compared with the two preceding years. In 1857, 1,538,988 cwts. were exported, of the value of £'7(;0,741 ; and in ]ii:>'\ 992 SODA, NITRATE OF. 1,018,289 cwts., of the value of £813,'72Y; whilst last year the quantity was 2,027,609, cwts., and the value £1,024,283. Scsquicarbonate. 2NaUU^,HC0'. This salt is frequently found native, and is described under Natuon, vol. ii., (which see.) Bicarbonate. NaCO^,HCO'. This salt is found in some mineral waters, as those of Carlsbad and Seltzer ; and is obtained from the waters of Vichy in large quantities. It is prepared by saturating the monocarbonate with carbonic acid, for which purpose several methods are employed. 1. By passing carbonic acid into a solution of the moiiocavbonatc. — A cold saturated solution of the monocarbonate of soda is made, and carbonic acid, obtained by the action of hydrochloric acid on marble or challi, is passed into it ; the bicarbonate forms and pre- cipitates to a great extent, and is then collected, pressed to remove as much of the adhering liquid as possible. A fresh portion of the monocarbonate is dissolved in the mother liquor, and the passage of carljonic acid through it repeated. By this method a pure bicarbonate is obtained, but the process is costly. 2. By exposing solid inonocarbonate of soda to an atmosphere of carbonic acid gas. — This is known as Smith's process. The crystals of the monocarbonate are placed on shelves, slightly inclined to allow the water to run off, in a large bo.\, containing a perforated false bottom ; carbonic acid is passed into this box under pressure, which latter is scarcely neces- sary, since the monocarbonate so rapidly absorbs the carbonic acid. When the gas ceases to be al)Sorbed, the salt is taken out and dried by a gentle heat. The crystals are found to have lost their water of crystiillization, and to have become opaque and porous, and a bicarbonate, still, however, retaining their original shape. These are giound between stones like flour, care being taken to avoid the evolution of much heat. This is the most economical process, but does not yield a perfectly pure product, yet, nevertheless, quite pure enough for ordinary purposes, the impurities contained in it being a little chloride of sodium and sulphate of soda, found in the original monocarbonate from which it was made, and even these are to a great extent dissolved and carried off by the water of crystallization as it escapes. 3. Its formation by the action of bicarbonate of ammonia has been already described. Bicarbonate of soda crystallizes in rectangular four-sided prisms, which require about ten parts of cold water to dissolve them, and if the solution be boiled, it loses carbonic acid, becoming first sesquicarbonate, and ultimately monocarbonate. As usuallyTnet with in commerce, this salt is a white powder. Its taste is slightly alkaline. It is largely used in medicine, for making seidlitz powders, &c. ; but the salt generally found in the shops is only a sesquicarbonate, or a mixture of bicarbonate and sesquicarbonate. — II. K. B. "soda, NITIIATE OF. (NaO,NOl) ^yn. cubic vitre ; QhWa, saltpetre. {Nitrate de sonde, Fr. ; Wiirfclsdlpetcr, Germ.) This important salt is found native in immense quanti- ties in Chili and Peru. It is, in some parts, found in beds of several feet in thickness. As found in nature it is tolerably pure, the principal impurities being chlorine, sulphuric acid, and lime. It is evident that nitrate of soda can be formed artificially by saturating nitric acid with soda or its carbonate, and evaporating the solution until the salt crystallizes. In analyzing a sample of the salt, it should be dissolved in boiling distilled water; any insoluble matters are to be removed by the filter, and, after being washed and dried, may be weighed. To the clear filtrate acidulated with pure nitric acid, nitrate of silver is to be added ; the precipitate of chloride of silver, when weighed with proper precautions, will en- able the amount of chloride of sodium to be calculated. For this purpose we say : as one equivalent of chloride'of silver is to one equivalent of chloride of sodium, so is the quanti- ty of cliloride of silver obtained to the quantity of chloride of sodium in the specimen taken. In another portion of the salt, the solution being prepared as before, the sulphuric acid may be determined by precipitation with chloride of barium ; and, in a third, the lime and magnesia are to be determined by precipitation, the first with oxalate of ammonia, and the latter in the filtrate from the oxalate of lime, by means of phosphate of soda and am- monia. The water may be determined by drying a known weight of the salt in the water bath until it ceases to diminish in weight. A good sample of nitrate of soda should not contain more than two per cent, of chloride of sodium. Solubility of Nitrate of Soda in Water. One part uf the salt dissolves in — 1'58 at a temperature of 21 '2° Fahr. 1-25 " " 320 1-36 " " 66-0 1-12 " " 82-4 0-77 " " 116-6 0-46 " " 246-2 The above table is not perfectly satisfactory, and tlie solubility of nitrate of soda in water at different temperatures requires reinvestigation. SOLDERS. 993 Nitrate of soda is not applicable for the preparation of gunpowder or fireworks, partly in consequence of its tendency to attract moisture from the air, and partly owing to the fact that mixtures made in imitation of gunpowder, but having nitrate of soda in place of nitrate of potash, explode far less powerfully than gunpowder itself. Nitrate of soda is extensively and economically employed as a source of nitric acid. It is also used for the purpose of being converted by double decomposition with chloride of potassium into nitrate of potash. It is employed in great quantities as a manure. The term cubic nitre applied to this salt is incorrect ; the crystals, it is true, appear cubic at a rough gl.ince, but they are in fact, rhombohedra, of which the angles are not very I'ar removed from those of a cube. — C. G. W. SODIUM. (Na.) This metal was discovered by Sir H. Davy, almost immediately after potassium, and by the same means, viz., by exposing a piece of moistened hydrate of soda to the action of a powerful voltaic batteiy, the alkali being placed between a pair of plati- num plates connected with the battery. By this process only very small quantities could be obtained, and processes have since been devised which provide it in almost any quantity, and since the demand for sodium in the maimfacture of aluminium by Wohler's process, principally by the exertions of M. St. Clair Deville, the cost of it has been considerably diminished. The process now adopted is the same as that for obtaining potassium ; an intimate mixture of carbonate of soda and charcoal is made by igniting in a covered crucible a salt of soda containing an organic acid, as the acetate of soda, &c., or by melting ordinary carbonate of soda in its water of crystalli- zation and mixing with it, while liquid, finely divided charcoal, and evaporating to dryness ; tliis mixture is mixed with some lumps of charcoal and placed in a retort, which is generally made of malleable iron ; but, owing to the difficulty of getting these sufficiently large, earth- enware or fireclay retorts have been used with success, and sometimes these are lined with or contain a trough of malleable iron. These retorts are so placed in a furnace that they are uniformly kept at a heat approaching to whiteness. Mr. Beatson {Pharmaceutical Journal^ vol. xv. p. 226) made an improvement in the process by which it can be carried on continuously for a week or fortnight. If the pro- portion of charcoal and soda be well regulated, the retort becomes nearly empty at the end of the process. In Mr. Beatson's process, as soon as one charge is worked oft" the receiver is removpd, and a fresh charge is introduced through the same tube as serves to convey the sodium to the receiver, by means of a semicircular scoop, so that the retort is kept at a constant temperature, and hence little loss of time. The receiver contains rock-naphtha, and is surrounded by cold water. The manuf\icture of sodium, when properly conducted, is much easier and more certain than that of potassium ; one advantage is, that the sodium does not unite with carbonic oxide to form the explosive compound, and the conducting tube is not so likely to be choked. The sodium which comes over is, however, mixed with some impurities, croconates, &c. ; and in order to separate the metal from these, Mr. Beat- son melted the sodium under mineral naphtha, in a cylinder, into which is fitted a piston, worked by a screw or hydraulic press, and when this is forced down the metal forms in a mass above it, -while the impurities remain at the bottom of the cylinder. The principal reaction which takes place in the retort, is the reduction of the soda by the charcoal, which is thus converted into carbonic oxide, which escapes through an aper- ture in the receiver made on purpose. NaO + C = Na -f CO Soda. Charcoal. Sodium. Carbonic oxide. Sodium is a silver-white metal, very much resembling potassium in every respect ; it is so soft at ordinary temperatures that it may be easily cut with a knife or pressed between the finger and thumb ; it melts at 194° F., and oxidizes rapidly in the air, though not so rapidly as potassium. Its sp. gr. is 0"972. When placed upon the surface of cold water it decomposes it with violence, but does not ignite the hydrogen which is liberated, imless the motion of the sodium be restrained, when the cooling effect is much less. When a few drops of water are added to sodium the hydrogen liberated immediately inflames, and such is also the case if it be put on hot water ; when burning it produces a yellow fianie, and yields a solution of soda. The equivalent of sodium is 23. When sodium is l)urnt in oxygen gas or in air, two different oxides are produced, viz. the protoxide, (NaO,) and another whose composition is uncertain, perhaps binoxide (NaO'^) or teroxide, (NaOl) These oxides also very much resemble the corresponding oxide of i)otas- sium. The princi[)al use of sodium is, as before stated, in the manufacture of aluminium, which is now carried on to a considerable extent. See Aluminiitm. — II. K. B. SOLDERS. Alloys which are employed for the purpose of joining together metals are so called. They are of various kinds, l)eing generally distinguished into hard and soft. Upon the authority of IIoltza[)pfel, the following receipts for solder are given, and these have been adopted, because, after a long and particular intiuiry in the workshops, we learn that these are regarded as very superior to any others recommended. Vol. III.— 68 994 SPECULUM METAL. Peioterers' Solder, (a) 2 Bismuth, 4 lead, 3 tin. (b) 1 Bismuth, 1 lead, 2 tin. Soft Spelter Solder. Equal parts of copper and zinc. Coarse Plumbers' Solder, (a) 1 tin, 3 lead, melts at about 500 F. (6) 2 tin, 1 lead, melts at about 360 F. Spelter Solder. 1 2 oz. of zinc to 1 6 oz. of copper. (For brass work the metals are generally mixed in equal proportions as above. For copper and iron the last given are usually employed.) The following Table of solders has been constructed by the late Mr. Iloltzappfel, from a Table of a much more extended character, published by Mons. H. Gaulthier de Claubry. Alloys and their Melting Heats. Fluxes. 1 2 3 4 5* 6 7 8 9 10 11 12 13 14 15 16 17 18 1 Tin 25 Lead - 558° Fahr. 1 '< 10 " - 541 1 '« 5 " - 511 1 " 3 " - 482 1 " 2 •' - 441 1 " 1 ' - 370 H " 1 " - 334 2 " 1 " - 340 3 " 1 " - 356 4 " 1 " - 365 5 " 1 " - 378 6 " 1 " - 381 4 Lead 4 Tin 1 Bismutli 320 3 " 3 " 1 " 310 2 " 2 " 1 " 292 1 " 1 " 1 " 254 2 " 1 " 2 " 236 3 " 6 " 3 " 202 A Borax. B Sal ammoniac. C Chloride of zinc. D Common resin. E Venice turpentine. F Tallow. G Gallipoli oil Modes of Applyisg Heat. a Naked fire. b Hollow furnace or muffle. c Imnrersion in melted solder. d Melted solder poured on. e Heated iron not tinned. / Heated copper tool tinned. g Blowpipe flame. h Flame alone, generally alcohol. i Stream of heated air. SPECULUM METAL. The metal employed in the mirrors of reflecting telescopes. The Earl of Rosso, who has been eminently successful in the production and publishing of large specula, says, in his paper published in the IVan.tactions of the Royal Society, "Tin and copper, the materials employed by Newton in the first reflecting telescope, are preferable to any other with which I am acquainted, the best proportions being 4 atoms of copper to 1 of tin, (Turner's numbers;) in fact, 126-4 parts of copper to 58'9 of tin." Mr. Rosse remarks tliat when the alloy for speculum metal is perfect, it should be white, glassy, and flaky. Copper in excess imparts a reddish tinge, and when tin is in excess, the fi-acture is granulated and less white. Mr. Ross pours the melted tin into the copper, when it is at the lowest temperature at which a mixture by stirring can be effected ; then he pours the metal into an ingot, and, to complete the combination, rcmelts it in the most gradual manner, by putting tlie metal into the furnace almost as soon as the fire is lighted. Trial is made of a small portion taken from the pot immediately prior to pouring. SriRlT OF SALTS. Hydrochloric or muriatic acid. SPIRITS OF WINE. Alcohol, (which see.) SPONGE. {Eponge., Fr. ; Schwavvn, Germ.) For a long time it was a disputed point whether the sponge of commerce belonged to the animal or the vegetable kingdom. Of late years the evidence has appeared to be conclusive as to its animal nature. The sponge consists of a soft gelatinous mass, mostly supported by an internal skeleton composed of reticularly anastomosing horny fibres, in or among which are usually imbed- ded siliceous or calcareous spicula. Sponges are rtfostly marine — two or three species only being found in fresh water. They are fixed by a kind of root, by which they hold firmly any surface upon which they once fix themselves. Sponges may be propagated by division, but more usually by gcmmules, which detach themselves from the parent body, and float about until they find a fitting resting-place, where they fix themselves and grow. The s[)()nges of commerce are ot)tained from the Mediterranean — Smyrna being the principal mart. They are collected by divers, many of whom have been trained to the work from their infancy. S[)onges are treated with muriatic (hydrochloric) acid to remove the lime. SPRUCE BEER is prepared as follows: — Essence of spruce, half a pint; pimento and ginger bruised, of each 4 ounces ; hops, from 4 to 5 ounces ; water, 3 gallons. Boil for ten minutes, then strain and add 1 1 gallons of warm water, a pint of yeast, and 6 pints of mo- lasses. Mix, and allow the mixture to ferment for twenty hours. SPRUCE, ESSENCE OV, is prepared by boiling the young tops of the Abies nigra, or black spruce, in water, and concentrating the decoction by evaporation. * No. 5 is the Phimherfs' sealed solder, which is as.saycd and then stamped by an officer of the Plumber's Coiii[iany. STEAM. 995 ST ANNATE OF SODA. The process of Mr. James Young for tlie preparation of stan- nate of soda, presents a very beautiful application of science. Instead of reducing metallic t'n from the ore, and oxidating the metal again to form the stannic acid at the expense of nitric acid, Mr. Young takes the native peroxide of tin itself, and fuses it with soda. The iron and other foreign metals present in the ore are insoluble in the alkali, so that by solu- tion of the fused mass in water, a pure stannate of soda is olitained at once. It is crystal- lized by evaporation, and obtained in elllorescent crystals containing nine equivalents of water. STEAM is a chemical compound of oxygen and hydrogen, in the proportion of 8 parts by weight of oxygen, to 1 of hydrogen. Its composition by volume is such, that the quan- tity of steam which, if it were a perfect gas, would occupy 1 cubic foot at a given pressure and temperature, contains as much oxygen as would, if uncombined, occupy half a cubic foot, and as much hydrogen as would, if uncombined, occupy 1 cubic foot, at the same pres- sure and temperature ; so that steam, if it were a perfect gas, would occupy two-thirds the si)ace which its constituents occupy when uncombined. Hence is deduced the following composition of the weight 1 cubic foot of steam would have at the temperature of 32' Fahr., and pressure of one atmosphere, (or 14'7 lbs. on the square inch,) if steam were a per- fect gas, and if it could exist at the pressure and temperature stated Data from the Expenments of Regnault. Half a cubic foot of oxygen at a pressure of one atmosphere ib. and temperature, 32"' 0-044628 1 cubic foot of hydrogen 0-005592 1 cubic foot of steam in the ideal state of perfect gas, at one atmosphere and 32" 0-050220 If steam were a perfect gas, the weight of a cubic foot could be calculated for auy given pressure and temperature by the following formula: — Weight of a cubic foot = 0-05022 lbs. x pressure in atmosphere — 493-°2 Temp.+4-61-°2 For example, at one atmosphere of pressure, and 212', the weight of a cubic foot of steam would be; — 0-05022 X "^ = 0-03679 lb. 673-'6 But steam is known not to be a perfect gas; and its actual density is greater than that which is given by the preceding formula, though to what extent is not yet known by direct experiment. The most probable method of indirectly determining the density of steam, is by computation from the latent heat of evaporation, from which it appears that at one at- mosphere and 212°, the weight of a cubic foot of steam is probably 0-0379 lb. The great- est pressure under which steam <;an exist at a given temperature, is called the pressure of sa'Hra(io7i for steam of a given temperature. The temperature is called the boiling point of water under the given temperature. The pressure of saturation is the only pressure at which steam and liquid water can exist together in the same vessel at a given temperature. It becomes necessary to understand correctly the method of determining fixed tempera- tu' es by certain phenomena taking place at them. Thus ice begins to melt at a point, which we call the Freezing Point, marked 32° upon the scale devised by Fahrenheit, (see TiiEKMo.METEK, vol. ii ;) and we determine the Boiling Point of water to be 212° on the same sc de, under the average atmospheric pressure of 14-7 lbs. on the square inch ; 2116-4 lbs. on the square foot; 29-992 inches of the column of mercury. At this latter point water ceases to be li'jiiid, and becomes vaporiform. F^-om 32" to 212°, all the heat which lias been jioured into the water, has effected no change of physical conclition, but the higher temperature being reached, a new condition is established, and steam is produced — this steam then be- ginning to act according to certain lixed laws. A cubic inch of water ^ evaporated under the ordinarji atino.iphcric prcsstire, is converted into a cubic foot of xteam. A cubic inch of ivater, evaporated under the at7nosphcric pressure, gives a mechanical force equal to what would raise a ton weiffht 1 foot high. These are the cfTects produced at 212' under the above-named pressure. Careful experiments have determined, within very small limits of erroi-, the following facts: — Steam under pressure of 35 lbs. per square inch, and at the temperature of '2t'A°, ;ert3 a force eijual to a ton weight raised one foot; under the ])ressure of 15 11 is. and at the temperature of 213°, it is 2,086 lbs., or al)out sevi'U per cent, less; and under 70 lbs. and at 306° it is 2,382 lbs., or nearly six and a half per cent, more than a ton raised a foot. It ia sufficient for all practical purposes to assume that each cubic inch evaporated, whatevet be the pressure, develops a gross mechanical effort equivalent to a ton weight raised 1 foot. As a given power is produced by a given rate of evaporation, to determine this the fol- lowing rules are applieal)le: — 996 STEAM. To produce the force expressed by one-horse power, the evaporation per minute must develoj) a mechanical force equal to 33,000 lbs., or about 15 tons raised 1 foot high. Fif- teen culiic inches of water would accordingly produce this effect, which, without evaporation would be equivalent to 900 cubic inches per hour. To find, therefore, the gross power developed by a boiler, it would l)e only necessary to divide the number of cubic inches of water evaporated per hour by 900. If, therefore, to 900 cubic inches be added the quantity of water per hour necessary to move the engine itself, independently of its load, we shall obtain the quantity of water per hour which must be supplied by the boiler to the engine for each horse power, and this will be the same whatever may be the magnitude or propor- tions of the cylinder. In the application of steam power, the most economical means have been attained in the pumping engines of Cornwall, where the steam is employed expansively. The following Tables will show the value of the Cornish engines. General Table of the Action of Cornish Steam Engines. Month ending August. Sept. Oct. Nov. Dec. Number reported . . . . - July 'JO. 23 24 24 24 24 24 oi Average load per square inch on piston, B in lbs. - - 119 11-4 11-5 11-8 12-5 12-7 Ml Average number of strokes per minute - 4-8 4-8 5-3 5-2 53 5-6 § Gallons of water drawn per minute - 8,773 8,980 8,772 4,031 4,373 4,000 BO i Average duty— being million lbs. lifted 1 ■g. foot high by the consumption of 1 cwt. of coals 61 -1 59-5 67-2 63-4 649 63-9 3 Actual horse-power employed - - . 710-8 740-1 725-8 787-8 845-8 814-6 Cui Average consumption of coals per horse- power per horse, in lbs. - - - - 4-0 4-1 3-5 4-3 41 4-1 Number reported IS IS 18 18 19 19 Number of kibbles drawn • - - - 62,608 66,162 65,645 68,895 71,135 74,705 a g Average depth of drawing, in fathoms 130-4 135-6 131-5 129-2 131-7 130-3 ~ S ■ Average number of horse whim-kibbles, b» to of 3 cwt. drawn the average depth, by o consuming 1 cwt. of coals 49 49-7 47-8 51-7 51-6 66-6 M^ . Average duty, as above .... 11-8 121 18-2 16-3 16-0 165 o S Number reported 6 6 6 6 6 6 c5 a Average number of strokes per minute - 13-9 14-0 14-8 14-9 14-1 13-8 Average dutv, as above . . . - 30 6 80-3 28-6 30-0 82-3 81-9 Vj " Horse power employed . - . . 88-5 90-1 54-9 58-2 104-9 111-1 Great Polgooth - - SOincb single 90-5 90-3 86-2 93-8 90-7 86-0 Par Consols - - 72 and 30-inch XA^ Sims' combined 89-9 94-1 88-3 92-0 94-5 . Fowey Consols - - 80-inch single 87-8 93-0 102-8 100 5 96-4 921 Par Consols - - 80-inch single 84-2 44-1 87-5 89-3 90-0 89-6 - •- ~ij i Callinston Mines - 50-inch single 821 78-1 70-4 62-5 67-0 72-0 Ph "5 [ Trelawny . . - - 50-inch single Par Consols - - 2-1 and 13-inch 77-4 70-3 • 73-9 67 74-7 Sims' combined 31 29-3 28-5 88-8 27 27-1 E S d Fowey Consols - - 22-inch double - 25-1 26-2 25-2 21-9 24-7 24-6 Fowey Consols - - 22-inch double - 20-3 19-5 18-3 20-8 24-2 239 ^ g'° Callington Mines - 22-inch double - 17-2 18-9 16-8 - . - Par Consols - - 24-inch sinsrle 16-0 16-3 . . . 15-4 Fowey Consols • . 18-inch double - 15-4 . . . . = S - Tamar Mines - - 30-inch single 43-3 44-4 41-4 45-8 441 39-2 "E.S 5 Great Polgooth - - 26-inch double - 33-4 40-8 24-8 29-4 S 5r.1i South Caradon - . 26-inch single SO-3 . 32 803 317 35-5 01 * '• Tincroft - - - S6-inch double - 29-8 35-0 88-5 44-0 Average Duty of Cornish Steam Engines. 184S. No. of pumping engines. Quantity of coal consumed. Water lifted 10 fathoms high. Average duty.* Tons. Tons. lbs. January - - - . 27 2,285 22,000,000 54,000,000 February . • - - 31 2,540 25,000,000 57,000,000 March .... 28 3,523 33,000,000 54,000,000 April - . - - 21 2,608 25,000,000 53,000,000 May 27 2,253 22,000,000 54,000,000 June 27 2,544 24,000,000 54,000,000 July 26 1,917 18,000,000 54,000,000 August .... 26 1,780 16,000,000 53,000,000 September ... 25 2,038 18,000,000 52,000,000 October .... 25 1,618 14,000,000 53,000,000 November .... 26 2,168 19,000,000 50,000,000 December - . . - 25 1,923 17,000,000 50,000,000 * The average duty in fifth coluum gives the number of lbs. lifted one foot high by the consumption ef a bushel of coal. STEEL. 997 Abstract of the Duty of Pumping Engines in Cornwall. Year. Number of Average duty. BEST ENOINE. reporied. Name of mine. Desoripllon. Engineers. Highest duty. 1S22 52 28,900,000 Wheal Abrabaru. Double cylinder. Woolf. 47,200,000 1S23 52 28,200,000 Do. Do. Do. 51,000,000 1S24 49 28.300,00(1 Polsooth. SO-in. cylinder. Sims. 46,90tt,0O(l 1S25 5G 32,000,000 D... Do. Do. 54,000,000 1S26 51 30,500.000 "Wheal Vor. Do. Sims &, Richards. 50.000,000 1827 51 32,lO;>,o;»o Wheal Towan. Do. Grose. 62,200,000 1S28 57 37,000,000 Do. Do. Do. 87,000,000 1S29 53 41,700,000 Do. Do. Do. 82,000,000 1S30 5G 4;j,3oo,ooo Do. Do. Do. 77,900,000 13-31 58 4:3,400,000 Do. Do. Do. 77,700,000 1S32 59 45,000,000 Whral Vor. Do. Elchards. 91,400,000 H33 5S 46,600.000 Do. Do. Do. 8S,.^00,000 183-t 52 47,800,0 Fowey Consols. Do. West. 97,900,000 1835 51 47,800,000 Do. Do. Do. 95,800,000 1836 61 46,600.000 Wheal Darlinston. Do. Eustis. 95,400,000 1837 58 47,000,000 Fowey Consols. Do. We.st. 85,000,000 1833 61 50,000,000 Wheal Darlington. Do. Eustis. 78,100,000 1839 52 55.000,O;)0 Fowey Consols. Do. West. 77,800,000 1840 54 51,000,000 WHieal Darlington. Do. Eustice. 81,700,000 1841 56 54,700,000 United Mines. 85-in. cylinder. Hocking & Loam. 101,900,000 1842 49 53,800,000 Do. Do. Do. 107,500,000 1843 36 60,000,000 Do. Do. Do. 96,100,000 In an inquiry upon the incrustations of the boilers of steam vessels, by M. Couste, it is stated that 8 or 10 per cent, of the heat of fuel is lost after the first few days' work — at Bor- deau-x: 15 per cent., and at Havre, after some days' constant work and observation, 40 per cent. ; in general practice it has been estimated that 40 per cent, of the heat of the fuel has been lost by the internal incrustations and deposits in the boilers of steam vessels. Tl« followincr results were obtained from French ocean steamers: — Stations. Sulphate of Lime. Carbonate of Magnesiii. Free Magnesia. Iron and Alumina. Water. Hamburg, deposit from the Burface of the boiler (partly crystallized) .Mediteiranean, tubular boiler (amorphous) - -Mediterranean, (amorphous deposit) . . - 85-20 84-94 80-90 2-25 2-34 3-19 5-95 7-66 10-35 0-41 C-50 6-5 4-65 4-56 An essential character of the sea-water incrustations is that they are free from the deposit of calcareous carbonates. STEEL {Acici^ Fr. ; Stahl, Germ.) is a carburet of iron, more or less freed from foreign matter, and may be produced by two processes opposed to each other. First, by working pig iron, whicli contains 4 or 5 per cent, of carbon, in a suitable furnace, until such carbon is reduced to th.it quantity required for constituting steel, which is about 1 per ceflt. ; the sec- ond method is to heat iron bars in contact with charcoal, until they have absorbed that quantity of carbon which may be required. Steel may be classed into three kinds: — 1st. Natural steel, which is manufactured from pig iron direct. 2d. Cemented or converted steel, which is produced by the carbonization of wrought iron. 3d. Cast steel, which is produced by the fusion of either natural or cemented steel, but principally from the latter. The various kinds of iron which arc used for the manufocture of steel are imported principally from Sweden, Norway, and Russia ; but the high price of Swedish and other steel iron has for the past few years compelled the consumers to look elsewhere for a supply of foreign-made iron, whilst at the same time every encouragement has been offered to Engli.sh manufacturers so to improve their steel irons as to render them at lea.st suitable for the pro- duction of steel good enough for tlie manufacture of coach springs and such other purposes. England now furnishes a large quantity of iron suitable for steel purposes, which may be estimated at 20,000 tons per annum ; this iron is manufactured with great care, often with an admixture of charcoal pig iron, aiul various chemical reactives, which arc atided at the caprice of each manul'acturer, but the object of which is to discharge the deleterious matters and to reduce the semi-metals. • It is of the highest importance that the iron used for steel purposes should be as pure and free from foreign matters as possible ; those irons which at present enjoy the highest reputation are tho.se manufactured from the Danncmora ores in Sweden ; the whole of the steel irons produced in that country are smelted from the black oxides, containing usually 60 per cent, of metal. Natural or German steel is so called becau.se it is produced direct from pig iron, the result of the fusion of the spathosc iron ores alone, or in a small degree mixed with the 998 STEEL. brown oxide ; these ores produce a highly crystalline raetal, called spiegle-eisen on account of the large crystals the metal presents. This crude iron contains 4 to 5 per cent, of car- bon, and 4 to 5 per cent, of manganese. Karsten, Hassengratz, Marcher, and Reaumur, all advocate the use of gray pig iron for the production of steel ; indeed they distinctly state that the best qualities cannot be produced without it ; they state correctly that the object of working it in the furnace is to clear away all foreign matters, but there can be no advantage gained by retaining the carbon, and combining it with the iron. This theory is incoriect, although it is supported by such high authorities ; gray iron contains the maxi- mum (juantity of carbon, and consetjuently remains for a longer time in a state of fluidity than iron containing less carbon; the metal is not only mixed up with the foreign matter it may itself contain, but also that with which it may become mixed in the furnace in which it is worked. This prolonged working, which is necessary in order to bring highly carbon- ized metal into a malleable state, increases the tendency to produce silicated oxides of iron; these mixing with the steel produced render it red short, and destroy many good qualities which the pig iron may have originally possessed. The semi-metals produced tend also to prevent malleability; the use of highly carbonized it7(j7e ^ii^ iro7i is equally inapplicable, and cuases a laige consumption of charcoal, as well as waste of metal. In Austria, where a large (juantity of natural steel is produced, the fluid metal is tapped from the blast furnace into a round hole ; water is sprinkled on the surface, which chills it, and thus forms a cake about half an inch thick. This is taken from the surface, and the operation is again per- formed until the whole is formed into cakes; they are then piled edgewise in a furnace, and covered with charcoal, and heated a full red heat for about 48 hours ; by this process much of the carbon is discharged. These cakes are then used for producing steel in the refinery. A much superior quality is thus obtained with greater economy. It appears that the most perfect plan for manufacturing the steel is to free the crude metal as much as possible from its impurities whilst in a fluid state. There is a process patented by Mr. Charles Sandei-son of Shetfield, which fulfils all that is required. The crude metal is melted on the bed of a reverberatory furnace, and any chemical reagent is added capable of disengaging oxygen during its decofnposition. Carbonic acid or carbonic oxide gases are produced by thB union of the oxygen with the carbon contained in the fluid iron, which is thus eliminated ; the gases so produced, being unable to reenter the metal, either pass off" in vapor, or act upon the silicates or other earthy compounds which the crude iron may contain, precipitating the metallic part and allowing the earthy matter to flow away as slag : a refined metal is thus produced of veiy great purity for the production of steel. The metal itself being to some extent decarbonized, the steel is more quickly produced, which secures economy in charcoal, time, and waste of metal, &c. ; the purity of the metal also prevents the formation of those deleterious compounds, which, when they are incorporated with the steel, seriously injure the quality. Natural steel manufactured from this purified iron has been found of very supeiior quality, and more uniform. The furnaces used for the production of natural steel are like the refineries in which charcoal iron is produced. In all countries their general construction is the same, but each lias its own peculiar mode of working. We find, there- fore, the (German, the 8tyrian, the Carinthian, and several other distinct methods, yet all producing steel from crude iron directly, although pursuing different modes of operation. These differences arise from the nature of the pig iron each country jjroduces, and the peculiar habits of the workmen. These modified processes do not affect the thcori/ of the manufacture of the steel, but rather accommodate themselves to the peculiar character of the metal produced. Fiff. 014 .sliows a ground plan of the furnace; fg. G15 an elevation; and /?)ut there are a f;ir gi eater nun.ber of instances in which steel is not adapted for the njanufacture of the article for which it was expressly made. Cast steel may be manufactured lor planir.g, borirg, or turning tools; its delects may be, that the tools, when made, ciack in the process of hardening, or that the tool, whilst exceedingly strong in one pait, will be found in ar.other part utterly useless. Cast steel may be wanted for the engraver. It niay be produced apparently perfect, and with a clear surface, but may be so improperly manufactured, that when the plate has been engraved and has to be hardened, it is found covered with soft places. The trial is even greater when the engraving is transferred by pressure to another plate. It is, therefore, evident that a steel-maker must not only attend to the intrinsic quality of his steel, but he has to use his judgment as regards the degree of hardness and tenacity which it should pos- sess, so as to iidapt it to the peculiar requisites vessel w;is brouglit into an inclined position, to receive the charge of crude iron, dnri|g which time -the tuyires were above the surface of the metal. As soon as the whole cluirge was run in, tlie vessel was moved on its axes, so as to bring the tuy6res l)elow the level of the metal, wlien the process was at once brought into full activity, and twenty small, though powerful, jets of air sprang upward through tlie fluid mass; the air, expanding in volume, divideil itself iiito glol)ules, or ))urst violently upward, carrying with it a large ((uantity of the fluid metal, which again fell back into the boiling mass below. Tlie oxygen of the air appeared, in this process, first to produce the combustion of the carbon contained in the iron, and at 1008 STEEL. the same time to oxidize tlie silicium, producing silicic acid, which, uniting with the oxide of iron, obtained by the combustion of a small quantity of metallic iron, thus produced a fluid silicate of the oxide of iron, or ' cinder,' which was retained -in the vessel and assisted in purifying the metal. The increase of temperature which the metal underwent, and which si'cuied so disproportionate to the quantity of carbon and iron consumed, was doubtless owing to the i'avorable circumstances under which combustion took place. There was no iutcivcpting material to absorb the heat generated, and to jirevent its being taken up by the ii:ctal, for heat was evolved at thousands of points, distributed throughout the fluid, and when the metal boiled, the Avhole mass rose I'ar above its natuial level, iorming a sort of spongy froth, with an intensely vivid combustion going on in every one of its numberless, ever-changing cavities. Thus, by the mere action of the blast, a ten perature was attained, in the largest masses of metal, in ten or twelve minutes, that whole days of exposure in the most powerful furnace would fail to produce. " The amount of deearbonizatiou of the metal was regulated, with great accuracy, by a meter, which indicated on a dial the number of cubic icet of air that had passed through the metal ; so that steel of any quality or temper could be obtained vith the greatest cer- tainty. As soon as the metal liad reached the desired point, (as indicated by the dial,) the workmen moved the vessel, so as to pour out the fluid malleable iron or steel into a founder's ladle, which was attached to the arm of a hydraulic crane, so as to be brought readily over the moulds. The ladle was provided with a flre-elay plug at the bottoni, the raising of which, by a suitable lever, allowed the fluid metal to descend in a clear vertical stream into the moulds. When the first mould was filled, the plug valve was depressed, and the metal was prevented from flowing until the easting ladle was moved over the next mould, when the raising of the plug allowed this to be filled in a similar manner, and so on until all the moulds were filled. " The easting of large masses of a perfectly homogeneous malleable metal into any de- sired form rendered unnecessary the tedious, expensive, and uncertain operation of welding now employed wherever large masses were required. The extreme toughness and extensi- bility of the Bessemer iron was proved by the bending of cold bars of iron 3 in. square, under the hammer, into a close fold, without the smallest perceptible rupture of the metal at any part; the bar being extended on the outside of the bend from 12 in. to 16f in., and being compressed on the inside from 12 in. to 7^ in., making a difference in length of 9^ in., between what, before bending, were the two parallel sides of a bar 3 in. square. An iron cable, consisting of four strands of round iron li in. diameter, was so closely twisted, while cold, as to cause the strands at the point of contact to be permanently imbedded in each other. Each of these strands had elongated 12i in. in a length of 4 ft., and had dimin- ished Vio of an inch in diameter, throughout their whole length. Steel bars, 2 in. square and 2 ft. G in. in length, were twisted cold into a spiral, the angles of which were about 45 degrees ; and some round steel bars, 2 in. in diameter, were bent cold under the hammer, into the form of an ordinary horse-shoe magnet, the outside of the bend measuring 5 in. more than the inside. " The steel and iron boiler plates, left without shearing, and with their ends bent over cold, afforded ample evidence of the extreme tenacity and toughness of the metal ; while the clear, even surface of railway axles and pieces of malleable iron ordnance were examples of the perfect freedom from cracks, flaws, or hard veins, which forn/S so distinguishing a characteristic of the new metal. The tensile strength of this metal was not less reniaikable, as the several samples of steel tested in the proving machine at Woolwich arsenal bore, according to the reports of Colonel Eardley Wilmot, R.A., a strain varying from 150,000 lbs. to 160, 9U0 lbs. on the square inch, and four samples of iron boiler plate from 68,314 lbs. to 73,100 lbs. ; while, according to the published experiments of Mr. W. Fairbairn, Stafibrd- shire plates bore a mean strain of 46,000 lbs. ; and Low Moor and Bowling plates a mean of 57,120 lbs. per square inch. " There was also another fact of great importance in a commercial point of view. In the manufacture of plates for boilers and for shipbuilding, the cost of production increased considerably with the increase of weight in the plate ; for instance, the Low Moor Iron Company demanded £22 per ton for plates weighing 2i cwt. each ; but if the weight ex- ceeded 5 cwt., then the price rose from £22 to .£"'.7 per ton. Now with cast ingots, such as the one exhibited and from which the sample plates were made, it was less troublesome, less expensive, and less wasteful of material, to make j)lates weighing from 10 cwt.' to 20 cwt., than to produfle smaller ones ; and indeed there could be but little doubt that large plates would eventu *ly be made in preference, and that those who wanted small plates would have to cut them from the large ones. A moment's reflection would, tlierefore, show the great economy of the new process in this respect ; and when it was remembered that every riveted joint in a plate reduced the ultimate strength of each 100 lbs. to 70 lbs., the great value of long plates for gir of testing the strength of the solution is to take a wine-glassful and drop a little hydrochloric acid into it ; by this means the wliolc of the silica in the solution is thrown down l)y the acid combininir witli tlic ' soda, so as to form chloride of sodium. The precipitated silica presents an apjiearancc resembling half-ster, the stop-cock 7, in the steam-pipe communicating with the jacket, is shut, and a cock in the pipe 8 is opened. The pressure of the steam in f then forces the fluid silicate through the pipe 8 into the vessel ii, 1012 STONE, ARTIFICIAL. where it is allowed to stand for a sliort time to deposit any sediment which it may contain. From II it is then conveyed by the pipe 9 to the evaporating pan k, which has a steam- jacket, A-, supplied with steam by the pipe 10. The cement is then boiled in the evaporating pan until it becomes of the consistency of treacle, when it is taken out. The specific grav- ity of the cement, when ready for use, is about 1-600. The general proportions of the ma- terials used in making up the artificial stone are about the following : — 10 pints of sand, 1 pint of powdered flint, 1 pint of clay, and 1 pint of the alkaline solution of flint. These ingredients are first well mixed in a pug-mill, and kneaded until they are thor- oughly incorporated, and the whole mass becomes of a perfectly uniform consistency. When worked up with clean raw materials, the compound possesses a putty-like consistence, which can be moulded iuto any required form, and is capable of receiving very sharp and delicate impressions. The peculiarity which distinguishes this from other artificial stones consists in the em- ployment of silica both as the base and the combining material. Most of the varieties of artificial stone hitherto produced are compounds, of which lime, or its carbonate, or sul- phate, forms the base ; and in some instances they consist in part of organic matters as the cement, and having inorganic matters as the base. To produce difl'erent kinds of artificial stone, adapted to the various purposes to which natural stones arc usually applied, both the proportions and the character of the ingredients are varied as circumstances require. By using the coarser description of grits, grinding- stones of all kinds can be formed, and that with a uniformity of texture never met with in the best natural stones. Any degree of hardness or porosity may also be given, by varying the quantity of silicate employed, and subjecting it to a greater or less degree of heat. For some descriptions of goods a portion of clay is mixed with the sand and other ingre- dients, for the double purpose of enabling the material to stand up during the process of firing in the kiln, and to prevent its getting too nmch glazed on the surface. The plastic nature of the compound allows of the most complex and undercut patterns being moulded with greater ease than by almost any other material we are acquainted Avith, if we except gutta percha, which, however, has the drawback of being affected by common temperatures. The moulds employed are generally of plaster of Paris, and are so divided as to allow of the difTcrent pieces which cannot be withdrawn together being separately removed from the putty-like substance with which it has been filled. In filling the moulds the workmen use a short stick, with which they ram in the material, much in the way in which green sand is forced into contact with the pattern in an iron foundry, only with the difference, that the sand in this case is mixed with glutinous cement, which enables it to retain the form im- pressed upon it with much greater persistency and sharpness than is practicable with dry sand, or even loam. The casts, after being taken from the mould, are first washed over with a diluted mixture of the silicate, technically called " floating." The whole surface is then carefully examined, and any broken or rough portions are sleeked with a tool. It should have been mentioned that tlie plaster of Paris moulds, before being filled, are first painted over with oil and then dusted with finely-powdered glass, to prevent them adhering to the cast. In attempting, however, to carry out his plan, two difficulties of a rather formidable character presented themselves. It was found that, in the process of desiccation, the sur- face of the stone parted with the moisture contained in the soluble silicate, and became hardened into a tough, impervious coating, which prevented the moisture escaping from the interior of the mass. Any attempt to dislodge the water retained in combination with the silicate in the interior of the stone, by raising the temperature of the whole above 212 de- grees, had merely the effect of breaking this outer skin of desiccated silicate, and rendering the surface cracked, and uneven. Instead, therefore,, of allowing the stones to be dried in an open kiln, they were placed in a closed chamber or boiler, surrounded with a steam-jacket, by which the temperature of the interior chamljcr could be regulated. In order that no superficial evaporation should take place, while the stones were being raised to the temperature of the steam in the jacket, a small jet of steam was allowed to flow into the chamber, and condense among and on the surfiice of the goods; until, as the temperature of the interior of the stones rose to 212' and upward, they became enveloped in an atmosphere of steam, which effectually prevented any hardening of the surface. The minute vents or spiracles formed by the steam as it was generated in the interior of the ma.sses, remained open, when the vapor contained in the closed chamber was allowed slowly to escape, and afibrded a means of cgi'css to any mois- ture wliieh might still be retained among the particles of sand and cement. The whole of the moi.sture contained in the silicate of soda having been thus vaporized before it left the stone, an opportunity was afforded it by opening a communication with the external atmos- phere, to pass off, leaving the interior of the stone perfectly dry. Simiile as this arrange- ment may seem, we will venture to say that not one of our readers has hit upon the expe- dient through his own cogitations on the subject. STOKE, ARTIFICIAL. 1013 The process, in effect, consists in stewing the stones in a closed vessel, and when all the moisture which they contain is converted into vapor, allowing it to escape, so that no one part of the mass can be dried before another. By this means Mr. Eansome was enabled to desiccate his artificial stone without any risk of the cracking or warping which had hitherto been the result of his attempts to harden them by exposure in an open stove. After being thoroughly dried they are taken to the kiln ; but, instead of being placed in sepgirs or boxes of clay, as is usually done in the potter's kiln, the goods are first bedded up with dry sand, to prevent any risk of their bending or losing their shape while burning. Flat slabs of fire-clay are then used to separate the various pieces laterally, and similar slabs are placed over them to form a shelf, on which another tier of goods is placed. The tem- perature of the kiln is very gradually raised for the first twenty-four hours ; the intensity is then augmented, until at the end of forty-eight hours a bright red heat is attained, when the kiln is allowed to cool gradually for four or five days, when the goods are ready to be taken out. The purposes to which this artificial stone is now applied are of the most miscellaneous description, comprising grindstones, whetstones for sharpening scythes, gothic foliage and mouldings for ecclesiastical decorations, tombstones and monumental tablets, chimney- pieces, fountains, garden stands for flowers, statuary, &c. From being composed almost entirely of pure siliceous matter, it is not acted upon by acids, and is apparently quite insoluble, even in boiling water. By proportioning the amount of cement, and varying the character of the sand which enters into the composition of the stone, it can be made porous or non-porous, as may be desired. The average absorbent power is less than that of the Bolsover Moor Dolomite used in the erection of the Houses of Parliament, and a little more than that of the Crag- leight Sandstone. DipPExnALL Silica Works, Farxham, Scrret. The manufactory which bears this name was built for the production of artificial stone, from a material only recently discovered, and never before employed for this purpose : so'uhle silica. By this term is meant that kind of silica which is found to be readily dis- solved by boiling in open vessels with solutions of caustic potash or soda ; thus distinguished from the silica of flint, which is only soluble in such solutions at a temperature of about 300° Fahr. in a steam-tight boiler ; and from that of quartz or sand, which is altogether insoluble. Up to the period when this discovery was made, silica had been only knoNvn to exist naturally in the two latter forms, and the former was merely a chemical product, de- rived from one of them by artificial means. This was at any rate the case in England ; but it is riglit to state that a somewhat similar deposit was mentioned by M. Sauvage, a French chemist, before the researches were made to which this paper relates, as existinof in the De- partment des Ardennes. This information, however, has not been turned to any practical account ; and therefore a short history of the English discovery may not be uninteresting, as the latter has introduced to the world a new material applicable to a great variety of purposes. About ten years ago the late Mr. Paine, of Farnham, proposed to the Chemical Commit- tee of the Royal Agricultural Society of England that a complete analysis should be made of all the soils of the king lorn, for the purpose of ascertaining their value as natural ma- nures. He undertook, for his own share, the strata of the chalk formation ; and his thor- ough geological knowledge, aided by the chemical science of Professor Way, then consult- ing chemist to the Royal Agricultural Society, enabled him fully to complete the inquiry. Some of the results of this joint investigation were communicated to the public by Messrs. Paiue and Way, in the 12th volume of the Journal of the Royal Agricultural Soci- ety, in a paper entitled " On the Strata of the Chalk Formation." The" soluble silica deposit is thus described : — " Immediately above the ganit, with the upper member of which it in- sensibly intermingles, lies a soft white-brown rock, having the appearance of a rich lime- stone. It is very remarkable on account of its low specific gravity, and still more so con- sidering its position, by reason of the very small quantity of carbonate of lime which it contains. It is one of the richest subsoils of the whole chalk series, being admirably adapted for the growth of hops, wheat, beans, &c. At the enl of the paper it is remarked that a careful study of this rock may throw light upon the composition of soils. The same authors contributed another article to the 1 1th volume of the " Journal," on " the Silica Strata of the Lower Ch:ilk," in which they state that " when the former paper was published, they were not unaware that this stnitum contained a large proportion of silica in the form which chemists call " .soluble ;" but that they wished, before making public their discovery, to ascertain whether it existed in sufficient quantity to render it availal)le forajri- cultural use." They then detail the result of their researches during the intervening two years, as far as they concern agriculture, mentioning all the localities in which this stratum may be found in England, anrl the various ways of employing it beneficially as a manure. T icy allude to the fact tiiat it will be found useful in its application to the arts, and conclude 1014 STONE, PRESERVATION OF. with these remarks on its probable formation : — " It is not infusorial, for, with the excep- tion of a few f'oramiiiil'era, no traces of animal life can be observed in the rock by micro- scopical examination. It cannot have been subjected to heat of any intensity, or it would have been rendered insoluble in alkalies. It is plainly the result of aqueous decomposition; and it seems very reasonable to suppose that silicate of lime in solution derived from the older rocks may have met with carbonic acid produced either by vegetaljle and animal decay, or by volcanic agency, and at one and the same time carbonate of lime and gelatinous or soluble silica would have been formed. It should be remembered that we find these beds in immediate contact with the chalk ; we find chalk without silica, silica without chalk, and, in other cases, both intimately blended. There is therefore good reason for supposing that these productions have been in some way connected." While these investigations were going on, it was also found that the new material was useful in a variety of ways quite distinct from agriculture. Mr. Way's experiments led to the conviction that it would be serviceable in sugar-refining, in soap-making, in making ani- mal charcoal, as a deodorizer, and above all, in the production of aitificial stone. The two investigators chiefly turned their attention to this latter branch of the subject ; and in 1852 they took out a patent for " Improvements in the Manufacture of Burned and Fired Ware." In their specification they lay claim to the production of a superior class of burned goo.ls by using the " soluble silica," with such admixtures of ordinary clay or lime as may be required. By these means they propose to make any kind of artificial stone, more or less resembling natural stone ; blocks or slabs, excellent building bricks of any color, and good fire-bricks. They do not claim any novelty in moulding or burning, except that they consider that in some cases articles might be burned to a slight degree of hard- ness, then finished up by the use of tools, and afterward reburned to any hardness that might be required. Mr. Paine's many other duties for some time prevented his carrying this patent into effect ; but at last, feeling it to be incumbent on him to make public so important a discov- ery, in spite of failing health and arduous occupation he commenced building the " Dippcn- hall Silica Factory" in 1856. Unhappily, he was not able to give his personal attention to the manufacture, so that it never had the benefit of his experience and scientific knowledge, and his death in 1858 put an end to his discoveries. The factory has therefore been carried on from the first under serious disadvantages ; but enough has been done to prove that its founder was not mistaken in the importance which he attributed to the invention. It is at present managed in a very simple manner. The material is carefully grouTid, either wet or dry, according to the purpose for which it is required, and mixed with clays or chalk when necessary. The bricks, vases, and other arti- cles, are n:oulded in the ordinary way, and burned in round kilna The building bricks, vases, and terra-cotta wares of all descriptions are generally acknowledged to be superior to any thing of the same kind hitherto produced, both in appearance, finish, and durability. There are at present jiractical difficulties in the manufacture of large blocks of stone, which do not seem to have been contemplated by the projectors ; and the fire-bricks cannot yet be called superior to the Stourbridge manufacture, as was confidently expected. They are per- fectly infusible under any amount of heat, but they are friable, and cannot bear a sudden change of temperature. Still, when it is remembered that the works have been carried on without any assistance from without, these difficulties only serve as incentives to further endeavors ; and the present proprietor is convinced that all that is required to overcome them, and to raise the reputation of the " Dippenh.all Silica Works" to the height to which their originator expected it to attain, is a man of equal scientific attainment, to resume the labors wliich were so prematurely arrested. — C. P. STONE, PRESERVATION OF. The attention of the scientific world has for some time past been directed to the importance of providing a means for protecting the stone of our public buildings from the ravages of time and the injurious efi'ects of the polluted atmos- pheres of our manufacturing and populous districts. The principal cause of the ruinous decay which is so apparent in the national edifices, churches, mansions, &c., of this country, is generally admitted to be tiie absorption of water charged witli carbonic or other acid gases, which by its chemical action either decomposes the lime or argillaceous matter forming the combining nodiimi unitirg the several siliceous or other particles of which the stone is composed, or mechanically disintegrates those par- ticles by the alternate expansion and contraction caused by variations of temperature. Many processes have from time to time been suggested, and several patents secured, for filling up the pores of the stone, and thus preventing the admission of these deleterious agents; hut they have been mostly, if not entirely, composed of oleaginous or gun.my sub- stances or compounds, which, although possessing for a time certain preservative proper- ties, become decomposed themselves upon exj)Osure, and constantly require to be renewed ; whilst from the nature of these applications the discoloration necessarily produced is highly objectionable. A little reflection will be sufiBcient to satisfy a thoughtful mind, that in seeking for a STOVE. 1015 means of preserving the stone of our national buildings, &c., we ought not to rest satisfied simply with the application of any organic substances, however great may be their apparent preservatis'e qualities for a time, but should endeavor to supply the defects of nature with an indestructible mineral incapable of change by any atmospheric influences. The process of silicatization introduced by Kuhhnann has the disadvantage of requiring some considerable time before the atmosphere can do its work of effecting the necessary combination between the silica applied in solution to the stone, and the lime contained in it, and therefore, when it is applied to the external parts of any building, it is liable to be washed out before solidification has been secured. Mr. Fredericli Ransouie, advancing from his siliceous stone process a step further, meets the condition by eft'ecting a chemical change at once within the stone. Mr. Ransome thus describes his process : — " Having b?en led to consider the importance of preserving the stone-work of our pub- lic and private edifices from the decay resulting from the variable condition of our climate, and other causes, I directed my attention to the existing processes proposed for efiecting such an object, and more especially to that which has been for some time in use on the con- tinent, in which a soluble silicate is employed, and I found that this process, though having for its base so important and indestructible a mineral as silica, was nevertheless very imper- fect in its results. It appeared to me that one great cause of failure arose from the fact that the silicate, being applied in a soluble form, was liable to be removed from the surface by rain, or even the humidity of the atmosphere, before the alkali in the silicate could absorb sufficient carbonic acid to precipitate the silicate in an insoluble form. But another great and serious defect in this process still existed, viz., that even were it possible to effect the precipitation of the silicate, still it would be simply in the form of an impalpable powder, possessing no cohesive properties in itself, and therefore able to afford but little, if any, real protection to the stone. It seemed to me, therefore, necessary not only to adopt a process which should insure an insoluble precipitate being produced, independently of the partial and uncertain action of the atmosphere, but that, to render such means efficient, a much more tenacious substance than merely precipitated silica must be introduced ; and in the course of my experiments I discovered that, by the application of a second solution, com- posed of chloride of calcium, a silicate of lime would be produced, possessing the strongest cohesive properties, and perfectly indestructible by atmospheric influences. The mode of operation is simply this : — The stone or other material of which a building may be com- posed, should be first cleaned by the removal of any extraneous matter on the surface, and then brushed over with a solution of silicate of soda or potash, (the specific gravity of which may be raised to suit the nature of the stone or other material ;) this should be followed by a solution of chloride of calcium, applied also with a brush ; the lime immediately com- bines with the silica, forming silicate of lime in the pores of the stone ; whilst the chloride combines with the soda, forming chloride of sodium, or common salt, which is removed at once by an excess of water. From the foregoing description it will be apparent that this invention has not only rendered the operation totally independent of any condition of the atmosphere in completing the process, but the work executed is imaffeeted by any weather, even the most excessive rains. Experience has shown, that where once applied to the stone, it is impossible to remove it, unless with the surface of the stone itself. I do not confine myself solely to the solutions above referred to ; in some cases I prefer to use, first a solu- tion of sulphate of alumina, and then a solution of caustic baryta, when a precipitate of sulphate of baryta and alumina is formed, the main object being to obtain two or more solutions, which upon being brought into contact mutually decompose each other and pro- duce an indestructible mineral precipitate in the structure and upon the surface of the stone. The application is one of extreme simplicity, and the material used perfectly indestruc- tible. The rationale of the process is thus explained : a liquid will enter any porous body to saturation, whilst a solid cannot go any further than the first interstices next the surface. Take, then, two liquids capable of producing, by mutual decomposition, a solid, and by the introduction of these liquids into the cells of any porous body, a solid is produced by their mutual decomposition internally; erc/o, if a solid could not go in as a solid, it cannot come out as a solid, and chemical decomposition having destroyed the solvents, tliey will never again be in a state of solution. The patentee has secured to himself the application of this important principle, and whilst we name silicate of soda and chloride ,of calcium as the agent under mutual decomposition by contact for producing the chloride of sodium, and the imperishable silicate of lime, there are many other ingredients that are capable of producing like results. STOVE. Space will not admit of our descril)ing the Dutch or American stoves, which are mainly modifications of the ordinary forms, which are sufficiently well known. Pierce's pyro-pneumatic stove-grate, shown firj. 028, appears to meet the requirement of a stove, of an open fire, and good ventilation, in a remarkable manner. In the annexed sketch is delineated the operation of the pyro-pneumatic stove, when employed in a large room, fig. 624. The channel c serves to supply pure air from any 1016 STOVE. source external to the building. The amount of the supply is regulated by the valve at b, and the direction of the currents is shown by the arrows. The fresh air is warmed iu its 623 course through the stove, and ascends to the ceiling, where it becomes diffused, and then descends, passing off by the smoke-flue. A special tube, d, is provided for ventilating the gas-lights, as exhibited in fig. 624. yy yi y ii d 'd y a y ii" ii i The application of the pjro-pneumatic stove to tlie warming of churches is extremely Bimplc, and its eflects arc found highly satisfactory. It gives an abundant supply of fresh STRUVE'S MIXE VENTILATOR. 1017 air, warmed to the desired temperature, and thereby prevents the influx of an impure at- mosphere from vaults and other sources of pollution. It carries off the vitiated air by the smoke-due, or in cases where a more rapid ventilation may be desirable, the warmth which it imparts to the air is sufficient to create an ample current in any shaft or ventilator that may be provided i:i tbe roof or spire of the building. In all cases this apparatus is economical in a high degree, not only from the smallness of its first cost, but also froui the fact that the full effect of the fuel consumed in it is secured to the uses of warming and ventilation. One element of economy cannot be too strongly insisted upon, viz., the feeling of warmth and comfort (even if it only exist in the imagina- tion) which is communicated by seeing the glow and blaze of an open lire. It would, perhaps, be no exaggeration to say, that with close stoves, heating apparatus, and other arrangements, in whicU tliere is no appearance of warmth, a much liiyher temper- ature oft/ie at no sphere ix rejuired to make it even feel- as warm as in that of an apartment heated by an open fire. Indeed, it may be fairly asserted that most persons will tolerate iucouvenienee and submit to expense, provided they see the cheerful blaze of the open fire, which they are at liberty to approach at will, and in the ever-varying embers of which they can conjure up visions of the past and fancies of the future. One of the large pyro-pneu natic stove-grates, when in full operation, is found to be capable of healing an ap irtment containing 50,000 cubic feet of air. In a very large church, containing upward of 175,000 cubic feet of air, and capable of accommodating a congrega- tion of 1,5 JO persons, four of these stoves of moderate size, arranged in convenient posi- tions toward the angles of the building, so that every individual of the congregation may see the fire, are found to be sufficient in the coldest weather, and do not even require to be sustained in full action, except during a few hours in the morning. One of these stove- grates placed in the hall or lower part of a staircase, warms and tempers the internal cli- mate of a large hou-«e, and gives the whole building a plentiful supply of pure fresh air. One of the s:niller grates is capable of warming a large room. And whether in dwelling- houses, schools, churches, or apartments, the arrangements can readily be brought into oper- ation at a moderate cost, and without any (beyond the most trifling) interference with exist- ing structural arrangements. The same inventor has introduced what he calls the fresh air fire-lump stove-grate, which may be thus described : — Tiiis grate is formed of the purest and best fire-clay, moulded in suitable forsns, adapted to the varied arrangements that are found necessary, and consists of the open fire-grate bars m front, surrounded at the sides and back by the fire-clay lumps, around which lumps an air-chamber is formed, communicating with the external atmosphere, admitting air to a cavity in the lower part of the grate, which communicates with the mouths of the vertical channels in the earthen lumps that surround the fire. The warmth, which is communicated to the air through the body of these lumps, and which, from their small conducting power, rarely exceeds 90', and can never be excessive, causes it to ascend through openings in the upper part of tlie casing into the apartment ; its place being sup- plied by fresh accessions of air from below. The warm air thus admitted into the apart- ment floats above, and gradually descends as it cools, its place being supplied by warmer air from the stove-grate, and taking with it to t!ie fire all the impurities of respiration, which is carried away by the flue, in which the heat maintains a constant upward current. Valves are provided for regulating the quantity and temperature of the fresh air admitted, and its distribution into the apirtmsnt when warmed. STRIPPING LIQUID, SILVERSMITH'S, consists of 8 parts of sulphuric acid and 1 part of nitre. STRU VE'S MIXE VENTIL.iTOR. The striking novelty of this ventilator is the gigan- tic scale upon which it has been constructed. Although in principle a pump of the simplest form, some of the pistons have been made 20 feet in diameter, and two pumps are about being constructed 21 feet in diameter. See Ji;/. 625. In some mines to which the machine has been applied, the rarcfixction and ventilation have proved so strong as to prevent single doors being opened, unless protected by supple- mental doors. The circumstance of the air not being compressed in the machine, admits of large valve spaces, so that there is scarcely any appreciable resistance to the passage of the air through the machine. The annexed drawing, firj. 625, represents the machine in operation at the Governor and Company's large collieries at Cwm Avon, Glamorganshire; and the following list of licenses granted to several large colliery proprietors, is a convincing proof that this invention ranks high among the modern improvements of mining. The sectional view explains the internal construction, the darts showing the air-currents ascending tlie upcast pit a, from the interior of the mine into the machine. The piston n is sliown immersed in water, which forms an air-tight packing. The front or outlet valves K are shown in the external view of the ventilator. The end of the machine is represented open in the drawing, for the convenience of showing the inlet valves E, and of explaining the internal construction. 1018 STRYCHNINE. The air-ports, or valve-work, can be made three-fourths of the area of the pistons, thus reducing tlie resistance of the air-current through the machine to a minimum. A. The upcast pit B. Hollow pistons, made of ■wrought iron. c. Wrought iron tanks, resting on two blocks of uiasonry, and on six iron pillars. D. Beam work, resting on three blocks of masonry. E. The valve work and framing, fastened to sixteen upright pieces of timber, 9 inches square. F. Crank wheel of steam engine. G. Piston rods. These machines can be applied to winding shafts. Cost of machines about £200, for capacities of 10,000 cubic feet of air per minute. STRYCHNINE. C"H=^N■■'0^ The bitter poisonous principle contained in the different varieties of utrj/chnos. It is usually extracted for commercial purposes from the nux vomica bean, the seed of the S. nux voynica. It is a well-marked alkali, and yields a great number of crystalline salts with acids and metallic chlorides. Its true constitution has been fully made out by the researches of Messrs. Nicholson and Abel. Although a most valuable medicine in paralytic affections, when employed in very small doses, it is a dangerous rem- edy in unskilful hands, and has been the cause of numerous deaths arising from carelessness, without reckoning the many who have been destroyed by it at the hands of the poisoner. Some years ago a panic was occasioned by a rumor of its employment for the purpose of giving a bitter flavor to beer ; this has been shown to be incorrect. Still the quantities of it produced annually by various manufacturers could not fail to excite attention and uneasi- ness. As much as 1,000 ounces have been known to be purchased at one time. It has been proved, however, that the chief use is for the destruction of wild animals in Australia and other thinly peopled localities. A great number of processes have been devised for its preparation, but, after having been subjected to the extractive operations, the bean is gen- erally found almost as bitter as before, indicating a want of economy in the methods. Probably the best method of extraction would be to disintegrate the beaus with stron? sul- SUGAE. 1019 phuric acid, (which is ■without action on strychnine,) and then, after the addition of excess of alkah, to dissolve out the base with benzole or chloroform. The latter being distilled off would leave the strychnine nearly pure, and only requiring crystallization. It has been shown by John Williams, that one bean will by this process yield a considerable quantity of crystals of pure strychnine. The detection of strychnine has unhappily become a problem of only too frequent occur- rence in chemical laboratories. It is, therefore, most important that ready and accurate methods should be known for the purpose. The following process may be relied on ; it is founded on that adopted by Graham and Hofmann for the detection of it when present in beer. The stomach or other organic substance is to be cut small and boiled with dilute hydrochloric acid for a quarter of an hour. The acid fluid, after filtration, is to be carefully neutralized with potash, and then digested with recently ignited ivory black. The charcoal is to be separated by filtration, and, when well drained, is to be boiled with spirit of wine. The strychnine which will have been absorbed by the charcoal will be dissolved out by the spirit. The latter is then to be distilled off on the water bath. The contents of the retort, being transferred to an evaporating basin, are to be exposed on the water bath until dry. The residue is then to be tasted ; if bitter, the process may be completed, but if no bitter- ness is observed it is scarcely worth while to proceed, as the merest trace of strychnine is capable of exciting the sense of extreme bitterness. The residue is to have a slight excess of potash added, and is to be shaken up with chloroform. The chloroform being separated is to be evaporated oif. The operation must be repeated if the product be colored. The substance thus obtained is to have a little strong oil of vitriol added, and a piece of bichro- mate of potash is to be rubbed on the parts where the strychnine is supposed to be ; if pres- ent, rich deep purple streaks will become evident. — C. G. W. SUGAR. The following will show the composition of the various sugars, and their principal combinations with bases: — Cane sugar, or sucrose - . . . . C'"H"0" Grape or starch sugar, or glucose ... C'-H''^0",2II0 Fruit sugar, or fructose C'^H'-O" at 212° F. Milk sugar, or lactose C'^IP^0'^.5H0 Manna sugar, or mellitose - ... - C-*H**0",4H0 Compounds of cane sugar called sugarates. With soda NaO,C'"H"0» With potash ....-•-. KO,C"H"0" With lime CaO,C''H"0" With baryta BaO,C'=H"0" With lead C"^^0", or 2PbO,C''ffO» With common salt NaCl.C^^IP'O'^' Compounds of grape sugar ^ or glucose. 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CC CO ■^ -^ -t ■n' rt* ■* tP ■*»" *0 if; O O *C «0 iC »C to to ^ ^ ^ ^ « ^ ,-H OJ OI o< Ol o» !tototototctotci- '"-fTf-TiCiCinOiiOi^O* :totr:totototcb-t I o cj CO to Ci oi to Ci o^ t-O oi^oi o X '?',»o^^''^'-t»^,^'^. *^,'-'^,"-l'^J"-:.'^ ■^,'^ —,'*,'■',— ^'^ *^ — o-i zS 'O '-o t~ ^^ ::: '-^'.S'^ '""ft-^ y'j of -^ ■7-ioo iT^ '^ t-^ oi ■z>' '-^ yi^ I— .^^T-.— .i-t©1010I-?104rN'->i01COCOCOCOCOCOCO-r-f-f*-t*'* " ■ ' ' " * CO to OS CO to Cl O) J »— CO C3 -^ 01 CO »C to h- 03 C: -r-l CO -t- tiO to X*" of O Ol* ♦•-t-^-^otiOiOi-OirtiCifototototototototob-i- co t- o CO t— ; ^ ^ ^ ^ ^ C-1 C^I Ol 01 0» Ol 01 C-1 CO CO C0e0C0C0C0'^"*-^-f'^*t'0»f0O»Cii0t0t0^tDtOt0t0t0l-l-t- 110,2 11G,G 117,9 iiy,8 120.0 124,6 127.3 128,0 131,3 13^,0 135,3 136,7 138.0 1.19,4 140.7 142,0 143.4 144,7 146,1 147,4 148,7 1.50,1 151,4 1.52,8 1.54,1 1.55,4 156.9 158,1 1.59,5 160,8 16-2.1 1(13.5 164,8 166.2 167.5 16s,8 170,2 171,5 17-2,9 174.2 CO cc CO cc CO Tt. 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The drainage is diluted, filtered through animal charcoal, boiled, SUGAR. 1033 and passed lhroun;h the centrifugal machines, and results in a second quality of sugar, tlie crystals being smaller. The drainage from this is treated in a similar manner, and a third quality of crystals is the result. A fourth quality of crystals is also sometimes obtained, the drainage from which is again boiled and laid aside in large moulds to crystallize for about a week, when treacle and a low quality of " pieces" are the final result. The drainages are sometimes filtered along with inferior qualities of raw sugar. The ditfieulty with which these large and beautiful crystals obtained by this process dis- solve, is an obstacle to their extensive consumption. C'riisfied su(/a): — This process closely resembles the manufacture of loaf-sugar, but the raw sugar used is generally of an inferior quality. The filtration through the animal char- coal is in consequence not so perfect ; the concentration rescnibleg that of loafsugar, but the use of a heater is dispensed with, and the process of liquoring is also dispensed with where practicable. The first crystallization is called " crushed," and the second " pieces," the drainage from which goes by the name of " syrup." When this syrup is diluted, filtered through animal charcoal, and concentrated, it is called "golden syrup." Trca'iiietit of vioiasses. — Foreign and colonial molasses, containing a large proportion of crystallizable sugar, are purchased by refiners. The Muscovado molasses from Cuba, from Porto Rico, Antigua, and Barbadoes, are esteemed the best, but the quality of molas- ses deteriorates as improvements in the manufacture of sugar are introduced on the planta- tions. The treatment of molasses formerly was simple ; it was merely concentrated and allowed to stand for several weeks in large moulds to drain. The liquid was sold as treacle, aad the impure soft, dark sugar, called bastards, found a market amorr^st the poorer classes, especially in Ireland. The more recent and better plan is to dilute the molasses, filter it through animal char- coal, and concentrate to the crystalHzing point, but without forming crystals. This readily crystallizes in the moulds, and in place of the bastards and treacle a bright yellov/ sugar and a fair quality of syrup are the result. Good molasses yields 40 per cent, sugar, 40 per cent, syrup, the remaining 20 per cent, being water, dirt, and loss. Palm or Date Sugar. — Many trees of the palm tribe yield a copious supply of sweet juice, which, when boiled down, gives a dark brown deliquescent raw sugar, called in India jaggery. The wild date palm and the gommuto palm yield the largest proportion of this kind of sugar, which is chemically identical with the sugar from the cane, though the crude- uoss of the manufacture is very injurious to it, and causes a large proportion to assume the uncrystallizable condition. One-twenty-fourth of all the caue sugar extracted for useful pur- poses is obtained from the palm-tree. Bket-root Sugar. — The extraction of sugar from beet root, which has become an im- portant manufacture in several countries on the continent, especially in France and Ger- many, was developed in consequence of the difficulty of obtaining colonial sugar in France during the blockade in the time of Napoleon I. The high price of sugar (5?. per lb.) was not the only stimulus to invention, as a prize of a million of francs was offered by the Gov- ernment for the most successful method of manufacturing indigenous sugar. The beet is a biennial plant, native to the south of Europe. There are several varieties of this root, each fitted to its own climate and soil ; but the white Silesian beet is the most prized where it can be grown, on account of the large amount of sugar in the juice, and the comparative absence of salts ; it is less prone to decay when stored previous to use. The average com- position of the root of the sugar beet may be stated as follows : — Sugar lOi per cent. Gluten 3' " Woody fibre, &c. 5 " Water 81^" 100 The proportion of sugar varies very much. First, it is greater in some varieties thnn ofhcrs ; second, it is greater in small beets tiian in large ; third, in dry climates, especially when the climate is dry after the roots have begun to swell ; fourth, in light than heavy soils ; fifth, in the part above than under ground ; sixth, when mainn-e has not lieen directly applied to the crop. The average proportion of sugar extracted Croui beet is (> per cent., tiioiigh it is stated that Y.V per cent, is obtained in some well-conducted manufactories. In Fr.ince and B(;Igium tlie average yield is 14 or 15 tons of beet to the acre, while about Mag- dcl)urg they do not exceed 10 to 12 tons, but the latter are richer in sugar. During the first year of its life the root is developed to its full sizr, and secretes the whole amount of sugar which, in the natural life of the i)lant, funiislies tiu' material for the growtli and maturity of its u|)per ])art. It follows tliat when the plant is cultivated for its sugar, it is ripe for the sugar manufacturers when its first year's stage of development is complete. The time required for this depends upon that of the sowing, and upon the sea- son. Its criterion is the commencement of death in the leaves. 'When ripe the beet roots are dug out, the mould gently shaken oft", and the heads cut off", togetlier with as much of 1034 SUGAR. the root as shows the presence of leaf buds. As the action of light is detrimental even to the exhumed roots, the latter must be covered cjuicklv. If the quantity be small, thej- may be covered with the leaves which have been cut off. It is more usual, however, to pile them in heaps on the ground, to hinder the evaporation of their water, and to protect them from light and frost by covering the heaps with a tjiin layer of earth. These mounds are some- times sprinkled with water, which is taken up by the roots restoring to them the plumpness and crispness which they have lost in a dry season. BoussiNGAULT gave the following analvses of French beets: — Where grown. Time of taking from giouud, &c. !Per cent, of dry matter. Botanic school - Garden of M. Brogniart Yigneux - Grenelle - Eovillc, Menrthe Analyzed tiy M. Braconnet. Au,2. 2.— Roots small . - . . Sept. 1.— A root of 1100 grammes =; about H lb. Sept. 1. — Koot, 460 grammes = about 1 lb. 2i oz. Sept. 7. — Koot. TOO to SCO grammes Touns root of 03 srammes = 4'6 grains Sept. 26. -Koot from SO to 100 grammes =^ Si oz. Oct. 9. — Koot, 150 grammes = about 5 oz. Sept. 28.— Root, 500 grammes = 1 i',„ lb. Sept. 23.— Root. 700 grammes = H lb. - Aug. 7. — Root, 300 grammes = */,(, lb. - Aug. 11.— Root, 600 crammes = Ij lb. - Aug. 30.— Root, 1 kilogramme = 2 ',^ lb. Beet in flower, 200 grammes ;= about Violb. Beet of two years in seed . . . White beet of SiUsia . . . . Leaves of the beet - - - - . 9-5 7-4 9-4 10-0 13-7 161 14-1 16-9 130 15'5 12-6 13-1 16-5 5-5 15S 6-4 Water. I Sugar. I 92-6 90-6 90-0 86-3 84-9 85-9 831 87-0 84-5 87-4 86-9 83-5 945 84-2 93-6 50 4-2 5 7-3 5-9 100 n-9 8-6 8-9 8-2 8-6 00 10-6 1-3 Ligneous fibre and albumen. 4-5 2-5 2-3 1-9 4-4 8-2 2-7 6-6 2-S 3-1 3-3 2-5 31 3-6 added to the lig. matter. 1-0 1-6 0-8 3-4 1-8 1-7 to preceding 1-6 1-4 3-4 11» 21 The beet-root rasp is represented in fgs. 640, 641. a, a is the framework of the ma- 640 641 7» chine ; b the feed-plate, made of cast iron, divided by a ridge into two parts ; c, the hollow drum ; d, its shaft, upon either side of whose periphery nuts are screwed for securing the saw blades e, e, which are packed tight against each other by means of laths of wood ; / is a pinion upon the shaft of the drum, into which the wheel (j works, and which is keyed upon the shaft ^ ; i is the driving rigger ; k, pillar of support ; /, blocks of wood, with which the workman pushes the beet-roots against the revolving rasp ; ??;, the cliest for receiving the beet-pap ; «, the wooden- cover of the drum, lined with sheet iron. The drum should make 50() or 600 turns in the minute. By the process of M. Schutzenbach, the manufacture may be carried on during the whole year, instead of during a few winter months. At Waghiiusel, near Carlsruhe, this system is adopted. The beets having been washed, are rapidly cut up into small pieces, and sub- jected to the drying heat of a coke fire for six hours. They lose from 80 to 84 per cent. of their weight ; the dried root may be kept without injury for many months, and the sugar is extracted by infusion. At this colossal establishment, which in 1855 employed 3,000 people, and the buildings of which covered 12 acres of land, there were 20 infusing vessels * Add 9 of nitre. t Add 1'5 nitre ; the albumen added to the sugar. SUGAR. 1035 12 to 14 feet deep, and T wide. A cwt. of raw roots cost Vc?., and the dried root contained 46 to 47 per cent, of sugar ; the capital employed was eighty millions of francs. Whether the juice is extracted from fresh or dried beets the subsequent processes are the same. The juice, having been extracted citlier by infusion or by submitting the rasped pulp to hydraulic pressure, is placed in a shallow vessel, and mixed with as much milk of lime as renders it strongly alkaline ; it is then boiled, generally by means of a copper coil heated by high-pressure steam. The excess of lime is removed by passing a stream of car- bonic acid gas through the liquid. The gas is generally produced by forcing a stream of air through an enclosed coke fire. The liquid is next filtered through cloth concentrated to a specific gravity of 25' B., filtered through animal charcoal, and treated in all respects simi- larly to ordinary cane sugar in a refinery. Though the vacuum-pan is employed in most beet-root establishments, there are some manufacturers who continue to evaporate in open vessels. The large amount of water which has to be removed in the concentration of beet-root syrups involves the use of so much fuel that, to economize it, an ingenious apparatus has been constructed by M. Call, of Paris. The principle adopted is to use the steam generated from the ebullition of liquid in one vessel for boiling another, the steam from which in like manner boils a third. Maple Scgar. — The manufacture of sugar from the juice of a species of maple-trees, which grow spontaneously in many of the uncultivated parts of North America, appears to have been first attempted about 1752, by some of the farmers of New England, as a branch of rural economy. The total production of maple sugar has been estinjated at 45 millions of pounds, or the one hundred and twenty-fifth part of the whole quantity of cane sugar extracted for the use of man. The manufacture of maple sugar diminishes yearly in proportion as the native American forests are cut down. See Sugar, vol. ii. 642 1036 SUGAR. Potato Scgar. — The manufacture of sugar from starch derived from potatoes, from woody matter, and from rags, can be effected by treating them with sulphuric acid and heat ; but the process, interesting though it is, is rarely if ever adopted at present, as the sugar is inferior in quality to that obtained from the cane, and dearer in price. See Potato Sugar, vol. ii. a Animal charcoal. — One of the most important considerations for a sugar refiner is to furnish himself amply with bone charcoal of the best quality, and to devote unsparing atten- tion to the process of revivification. The theory of the action of bone charcoal upon solu- tions of raw sugar and other colored liquids need not be discussed here. It may, however, be observed, that but little is known upon the subject, and that the behavior of bone char- coal with respect to metallic oxides and various salts is as remarkable as its action upon coloring matter. After the raw liquor has been passed continuously through a filter of bone charcoal, the decoloring power of the charcoal becomes impaired, and finally lost. This power may be more or less restored by the following means : — 1st. Washing with water. 2d. Fermenta- tion. 3d. Washing with weak hydrochloric acid. 4th. Long exposure to air and moisture. 5th. Heating to redness. The last plan being the only one which does not materially injure the charcoal, and most completely restore^ its power, 642a C^ is the course almost invariably adopted ; it is however preceded by washing with water. Various forms of apparatus for reburning charcoal have been pro- posed and adopted, but the four fol- lowing methods are the chief at present used : — 1st. Burning in iron pipes. A furnace about six feet in length, and eighteen inches wide, is placed be- tween two rectangular chambers with which it communicates ; each chamber contains thirty-two cast- iron pipes of four inches diameter and nine feet in length, whose ex- tremities pass through the top and bottom of each chamber ; to the lower end of each pipe a sheet-iron cooler is suspended. When the charcoal kiln is in use, the pipes filled with charcoal are maintained at a dull red heat, and the charcoal is withdrawn from the coolers in measured quantities at such inter- vals of time as to allow it to be four hours under the action of the heat. The advantages of this plan are cheapness of first cost and sim- plicity; its disadvantages are first, that the charcoal is unequally burnt, the pipes near the furnace being more heated than those further re- moved from it ; second, the kilns require frequent repairs, some of the pipes being destroyed by the fire ; third, the amount of fuel re- quired is large ; fourth, the pipes are apt to become choked. 2d. Burning in fire-clay cham- bers. This plan, proposed by Mr. Parker, of London, and improved by Mr. G. F. Chantrell, of Liverpool, is becoming generally adopted. The plan consists in arranging narrow chambers, composed of fire- tiles, and containing charcoal, between small furnaces. Fig. 642 shows a section of Mr. Chantrell's kiln through one of the fire-places; fps. 642 «, 642 6, two front views of the same, c is the fire-door ; ii the furnace ; the products of combustion issue tlirough aper- tures in the arched roof of the furnace, and are compelled to take a zigzag course to the flue G, by means of horizontal floors of tiles, each floor being open at alternate ends, b, b are apertures for cleaning the flues or inspecting the state of the kiln ; l, l, the coolers ; m, the SULPHURIC ACID. 1037 measuring-box or receiver ; F, a heated floor for drying the charcoal previous to being re- burned ; N, the firing floor. The advantages of this system are, first, the charcoal is very equally burnt ; second, the amount of fuel required is small, not reaching ten per cent, of the charcoal reburned ; third, non- liability to gel out of order ; the ^'^-^ chief disadvantage is the amount of first cost. 3d. Reburning in rotating cylin- ders. This plan, like the former the subject of a patent, is used at the extensive establishment of Mr. G. Torr, London, the regularity and the excellence of the result being considered by him a sufficient com pensation for the costliness of the process. 4th. Reburning by means of superheated steam. This ingenious method, were it not for the expense of the apparatus, and practical dif- ficulties, would supersede the pre- vious methods. The apparatus is the invention of MM. Laurens & Thomas of Paris. A furnace is constructed, in the flues of which a number of cast-iron tubes, connect- ed together and ranged in order, are placed ; the products of com- bustion, after maintaining the pipes at a high temperature, impart heat likewise to the vase-shaped vessel before entering the chimney. A jet of steam being passed through, the pipesbecomes sufficiently super- heated to expel the moisture from the charcoal contained in the re- ceiver, and subsequently to raise it to a temperature of 600° F. This is sufficient to effect destructive distillation of the coloring matter absorbed by the charcoal. The process takes about eight hours ; the advantages of this method con- sist in the steam coming in absolute contact with every single grain of charcoal ; the distil- lates are effectually removed, and there is little or no risk of the charcoal being subjected to too high a temperature ; but the plan is expensive and inconvenient, and has not been adopted in England. To reburn charcoal the best methods are those which most rapidly remove the water, raise the temperature of each grain of charcoal to a uniform temperature of 700^ Fahr., and which admit of its being readily cooled without contact with the air. The influences of time and temperature, in the reburning process, are very marked ; in the best regulated refineries the decoloring power of the charcoal is frequently examined and recorded, and an analysis of the charcoal is made each month. SULPIIUlilC ACID, Vitriolic Acid, or Oil of Vitriol. (Acid sulfiirique, Fr. : Schwe- felxaiire, Germ.) This important substance now forms an extensive article of manufacture. It appears to have been known several centuries back. It is found in large quantities in the mineral kingdom, combined with bases, in some rivers in the free state, and in such quantity as to render the water acid. It was previously prepared by the distillation of sulphate of iron or green vitriol, from which it received its name of oil of vitriol or vitriol- ic acid. This, process is even now carried on in some p^rts of Germany to a certain ex- tent. It was afterwards found that it might be produced by the combustion of sulphur, and the ultimate further oxidation of the sulphurous acid, thus obtained, liy the means of nitric acid ; and from time to time improvements have been made in the process, until it is now almost, perhaps entirely, perfect, tmd is the process most generally adopted. We shall proceed to describe the process more fully, as it is now carried on. In the first place the sulphur is burnt on suitable hearths, and the sulphurous acid pro- duced is carried by flues, together with some nitrous and nitric acids, generated in the same f r.-nace from a mixture of nitre and sulphuric acid, into the large leaden chambers, into 1038 SULPHURIC ACID. which steam and air are also admitted ; hero the different gases react on each other, and the sulpluirous acid becomes converted into sulphuric acid, and falls into the dilute sulphuric acid which is placed in the bottom of the chamber, which thereby becomes stronger, and, when of sufficient strength, is drawn off, and concentrated first in leaden vessels, and finally in vessels of platinum. The apparatus nec^sary for the manufacture of sulphuric acid is 1. Hearth on which the sulphur is burnt. 2. Iron pot tor the nitre. 3. Leaden cham- bers. 4. Steam boiler. 5. Concentrating pans, (leaden.) 0. Platinum or glass retorts. The place where the sulphur is burnt is a kind of furnace, but instead of the grate there is a stone hearth or iron plate, called the sole. The nitre pot or pan is of cast iron. In it the nitre is decomposed by the sulphuric acid, and it is placed in the burner when required. The leaden chamber has the form of a parallelopiped, the size varying with the amount of work reiiuircd to be done To produce 10 tons of oil of vitriol weekly, the chamber should liave a capacity of 35,000 cubic feet ; or a length of 187 feet, a breadth of 12A feet, and a height of 15 feet. {Plmrmaceutical limes, Jan. 2, 1847.) The bottom is covered to the depth of 3 or 4 inches with water acidulated with sulphuric acid. These leaden chambers are sometimes divided into 3 or 4 compartments by leaden curtains placed in them, which cause the more perfect mixture of the gases. Fi^. C43 is a drawing of one thus divided, taken from Fereira's Materia Medico. 013 JliS Oil or Vithioi, Cii.vmi i: :. a. Steam boiler. Ii, Pection of furnace or hurner. r/.inil/. 1.' aden cmtains inun Uie roof of the chamber to within six inches of the floor, e. Leaden cm tain li-inir Iroin tlic floor to within si.x inciies of the roof, f/, Le.iden conduit or vent-tube for the di^charfre of uncondensable irases. It .should commu- nicate with a tall chimney to carry off these gases, and to occasion a slight draught through the chamber. These curtains serve to detain the vapors, and cause them to advance in a gradual manner through the chamber, so that generally the whole of the suljihurous acid is convert- ed into sulplmric acid and deposited in the water at the bottom before it reaches the dis- charge pipes ; but as such is not always the case, there are sometimes smaller chambers, also containing water, appended to the larger, from which they receive the escajiing gases before they are allowed to pass out in the air, and thus prevent loss. These smaller cham- bers are seen in Jiff. C44 c, d, also taken from Pereira's Materia Mcdica. r-i4 ,,,f!ifff'ni'niiieiiiBiiii*!?jii!iii»ira Oil of Vitkiol .Masufactoky. a, Sulphnrbnrnp.rorfurnace. b. First leaden chamber, e, rrss. This was al.so carried on in largo leaden chambers ; but instead of a contintious stream of air, as passes into the chambers, thi'ough the furnace by the continuous [jrocess, the chaml)crs were opened now and then to introduce frcsli atmospheric air. This ]irocess is, however, now generally abandoned, on account of tlie difficulties and (hdays attending it, though it afforded large pi'oducts in skil- ful hands. The following is just an outline of tlic process : — On the intermittent plan, after the consumption of each charge, and contjcn.sation of the product, the chamber was opened 1040 SULPHURIC ACID. and freely ventilated, so as to expel the residuary nitrogen, and replenish it with fresh atmospheric air. In this system there were four distinct stages or periods : — 1. Combustion for two hours ; 2. Admission of steam, and settling for an hour and a half ; 3. Conversion for three hours, during which interval the drops of strong acid were heard falling like heavy hailstones on the bottom ; 4. Purging of the chamljcr lor three-quarters of an hour. The complicated changes which take place in the leaden chambers during the conversion of the sulphurous acid into sulphuric acid, were first traced by M. Clement-Desormes. lie showed that hyponitrie acid and sulphurous acid gases, when mixed, react on each other through the intervention of moisture ; that there thence resulted a crystalline combination of sulphuric acid, binoxide of nitrogen, and water ; that this crystalline compound was instantly destroyed by more water, with the separation of the sulphuric acid in a liquid state, and the disengagement of binoxide of nitrogen ; that this gas re-constituted hyponitiic acid at the expense of the atmospheric oxygen of the leaden chamber, and thus brought matters to their primary condition. From this point, starting again, the particles of sul- phur in the sulphurous acid, through the agency of water, became fully oxygenated by the hyponitrie acid, and fell down in heavy drops of sulphuric acid, while the binoxide of nitro- gen derived from the hyponitrie acid, had again recourse to the air for its lost dose of oxy- gen. This beautiful interchange of the oxygenous principle was found to go on, in their experiments, till either the sulphurous acid or oxygen in the air was exhausted. They verified this proposition, with regard to what occurs in sulphuric acid chambers, by mixing in a crystal globe the three substances, binoxide of nitrogen, sulphurous acid, and atmospheric air. The immediate production of red vapors indicated the transformation of the binoxide into hyponitrie acid gas ; and now the introduction of a very little water caused the proper reaction, for opaque vapors arose, which deposited white star-form crystals on the surface of the glass. The gases were once more transparent and colorless ; but another addition of water melted these crystals with efiervcscence, when ruddy vapors appeared. In this manner the phenomena were made to alternate, till the oxygen of the included air was expended, or all the sulphurous acid was converted into sulphuric. The residuary gases were found to be hyponitrie acid gas, and nitrogen without sulphurous acid gas ; while unctuous sulphuric acid bedewed the hiner surface of the globe. Hence, they justly con- cluded their new theory of the manufacture of oil of vitriol to be demonstrated. By a modification of this last process, the manufacture of sulphuric acid from sulphur and nitre may be elegantly illustrated. Take a glass globe with an orifice at its top laige enough to take a lead stojiper, through which are fixed five glass tubes ; one in connection with a flask generating sulphurous acid from copper turnings and sulphuric acid ; the second in connection with a gasometer supplying binoxide of nitrogen ; the third in connection with a vessel capable of supplying a tolerable current of steam ; the fourth connected to another gasometer supplying atmospheric air ; and the fifth, which is left open, does not pro- ject far into the globe, and serves to carry off the residual nitrogen. By regulating the influx of the different gases and steam, the solid white crystalline compound may be alter- nately formed and again decomposed. The bottom of the glass globe is formed like a funnel, and the sulphuric acid, when formed, thus runs down the sides into a bottle placed beneath. Some difference of opinion exists about the composition of the crystalline com- pound thus formed sometimes in leaden chambers. It is probably a compound of sulphuric acid and binoxide of nitrogen N0"+2S0', but it is not decided if it contains water or not. Peligot (Ann. Chim. et Phys. 3me ser. xii. 1844) states that the sulphurous acid is oxi- dized ince-fsantli/ and cxclus'n-ebj by nitric acid only, and he accounts for it in this way : — The hj-ponitric acid (XO'') by contact with water is converted into nitric acid, and nitrous acid (2\0' + nO = HNO''-i-N(V), and the nitrous acid (XO^) is again decomposed by more water into nitric acid and binoxide of nitrogen 3XO'+HO = HXO^+2XO^ The binoxide of nitrogen by contact with atmospheric air is again converted into hyponitrie acid (XC-^- 0^ = X0^), which goes through the same changes as before. There are some points in the manufacture of sulphuric acid which require attention. 1 St. If the heat in the sulphur furnace is too high, or when there is not a sufficient supply of air, some sulphur sublimes, and is condensed in the chamber, and at last falls into the sulphuric acid at the bottom of the chamber. By this means, not only is less sulphuric acid produced, but the sulphuric acid, when drawn from the chamber, contains some sul- phur in suspension : in this case it must be allowed to stand, so as to deposit the sulphxu", which may be collected, washed, dried, and again used. If the sulphur were not removed before concentrating, it would, at the temperature requisite for evaporation, decompose the sulphuric acid, with the escape of sulphurous acid gas, and hence much sulphuric acid would ^'e lost. The reaction that would take place is represented by the following equation : — 2IIS0^ -f S = 3S0' + 2H0 Sulphuric acid. Sulphur. Sulphurous acid gas. TVater. 2d. If there is not a sufficient quantity of steam admitted into the chamber, the solid compound of sulphuric acid and binoxide of nitrogen, above mentioned, would be formed SULPHUKIO ACID. lOil on the sides of the chamber, and thus remove the oxidizing agent from action, and hence a large quantity of sulphurous acid would escape by the waste-pipe unchanged. 3d. A deficiency of nitric acid in the chamber also causes great loss ; the Bulphurous acid, as in the former case, escaping unoxidized. The first of these three subjects was counteracted by M. Grovelle, who, taking advan- tage of an idea put forth by M. Clement Desormes, constructed a furnace for burning the sulphur, so as to have a double current of air. lie substituted for the sole of the furnace some parallel bars of iron, on which were placed cast-iron pans or boxes, bound together, but leaving intervals for the entrance of air between each : these were filled with sulphur, which was then ignited, and thus a plentiful supply of air was constantly kept up. Faming, or Nordhausen sulphuric acid. At Nordhausen and other parts of Saxony, sulphuric acid continues to be made upon the old plan. This consists in first subjecting sulphate of iron or green 645 vitriol to a gentle heat, by which it is deprived of its water of crystallization ; it is then distilled in earthen- ware, tubular, or pear-shaped retorts, of which a large number are placed in a gallery furnace. Fig. 645, the fire-place ; abb, chamber on each side of the fire-place, for depriving the green vitriol (c c) of its water. To these retorts ai-e adapted earthenware receivers, into which some ordinary sulphuric acid is previously placed, to condense all the anhydrous sulphuric acid which comes over. The heat is raised gradually, and at last the retorts are subjected to an intense heat, which is kept up for several hours. Some sulphurous acid gas escapes, arising from the decomposition of some of the sul- phuric^acid of the sulphate by the oxide of iron, and nothing remains in the retorts but sesquioxide of iron. 3FcS0^ = Fe'O' -}- 280^ + SO' Green vitriol. Oxide of iron. Anliydrous sulphuric acid. Sulphurous acid Anhydrous sulphuric acid. This is most easily obtained by subjecting the Nordhausen sulphuric acid to a gentle heat in a glass retort, to which is adapted a dry receiver placed in ice. White fumes of anhydrous sulphuric acid come over and are condensed in the re- ceiver. Care must be taken to avoid water coming into contact with it, as it unites with it with some violence. HSO*SO» = HSOn + SO' Nordhausen sulphuric acid. Common sulphuric acid. Anhydrous sulphuric acid. It is best to have a receiver, which can be hermetically sealed as soon as the operation is completed. Properties of the different Sulphuric Acids. Anhi/drous sulphuric acid. SO'. This is a white crystalline body, very much resem- bling asbestos in appearance. Exposed to the air, some of it absorbs moisture, and the rest flies oif in white fumes. Dropped into water it produces a hissing noise, just like red- hot iron, and in large quantities causes explosion. It melts at 66° Fahr., and boils at about 120" Fahr. The sp. gr. of the li(iuid, at 78^ Fahr., is 1-97, (Pcrcira,) and that of its vapor 3'0, (Mitschcrlich.) It does not present acid properties unless moisture be present. Nordhausen sulphuric acid. IISO', SO'. This is an oily liqiiid, generally of a brown color, (from some organic matter,) which gives off white fumes of anhydrous sulphuric acid when exposed to the air. Its sp. gr. is about 1-9. It is imported in stoneware bottles, having a stoneware screw for a stopper. It is probably only a solution of anhydrous sul- phuric acid in ordinary oil of vitriol, as, after being subjected to a gentle heat, nothing re- mains but the latter. It often contains several impurities. It is principally used for dissolv- ing indigo, which it does completely without destroying the color. Ordinary sulphuric acid or oil of vitriol. II80''. Sp. gr. 1'845. This is, when pure, a colorless, transparent, highly acrid, and most powerful corrosive liquid. It is a very strong mineral acid, one drop being sufficient to communicate the power of reddening litmus paper to a gallon of water, and produces an ulcer if placed upon the skin. It chars most or- - ganic substances. This depends upon its attraction for water, which is so great that, when ex- posed in an open saucer, it imbibes one-third of its weight from the atmosphere in twenty- four hours, and fully six times its weight in a few months. Hence it should be kept excluded from the air. If four parts, hy weight, of the strongest acid be suddenly mixed with one part of water, both being at 50' Fahr., the temperature will rise to 300'' Fahr. ; while, on the other hand, if four j)arts of ice be mixed with one of sulphuric acid, they immediately li(}uefy and ;i'i1c the thermometer to 4° below zero. In this last case the heat, that would otherwise Vol. III.— 66 1042 TANGLE. have been given off, has been employed in liquefying the ice. Upon mixing the acid and water they both suffer condensation, tlie dilute acid, thus formed, occupying less space than the two separately, and hence the evolution of heat. This affinity for water, which sulphuric acid possesses, is often made use of for evaporating liquids at a low temperature. The liquid is placed in a dish over another dish containing sulphuric acid, and both are plac- ed under the receiver of an air pump. Such is the rapidity with which the evaporation is carried on, that if a small vessel of water be so placed it will speedily be frozen. Sulphuric is decomposed by several substances when boiled with them ; such are most organic sub- stances, sulphur, phosphorus, and .several of the metals, as mercury, copper, tin, &c. Sulphui ic acid of s|). gr. r845, boils at about 620° Fahr., and may be distilled unchanged. This is the best way to oi)tain it pure. It is a most powerful poison. If swallowed in its concentrated state, even a small (juantity, it acts so powerfully on the throat and .'y M. Pclouze, which consists in exhausting the powdered gall-nuts by allowing ordinary ether to percolate through them in a proper apparatus. The ether, which always contains some water, separates at tlie bottom of the ap- paratus into two distinct layers; the under one, being the water, containing all the tannic acid, and the upper one, the ether, containing the gallic acid and coloiing matter. The solution of tannic acid is washed with ether and evaporated gently to dryness, when the gallo-tannic acid is left as a pale buff-colored amorphous residue. Some gall-nuts contain a^ much as 67 per cent, of gallo-tannic acid, and about 2 per cent, of gallic acid, (Guibourt.) Gallo-tannic acid is freely soluble in water, soluble in di- luted alcohol, slightly in ether. The tannic acids are all remarkable for the avidity with which they absorb oxygen; the gallo-tannic acid becoming gallic acid. A saturated aqueous solution of gallo-tannic acid is precipitated by sulphuric, hydrochlo- ric, phosphoric, and some other acids. When boiled for some time with diluted sulphuric or hydrochloric acid it is converted into sugar and gallic acid, (Strecker;) the latter crystal- lizes on cooling, whilst the glucose remains in solution. C%"0=^ + lOHO = 3(3HO C"H'0') + C'-n'=0"2aq. GalIo-t.innic acid. Gallic acid. Glucose. The composition of the gallo-tannates is but imperfectly knowa, and it is not decided if the acid be dibasic or tribasic. A solution of gallo-tannic acid gives, with persalts of iron, a bluish black precipitate, which is the basis of ordinary black writing ink. The most remark- able compound of gallo-tannic acid is that which it forms with gelatine, which is the basis of leather. See Tanxixg. By the reaction of heat gallo-tannic acid is converted into pyrogaltic acid, and this dis- tinguishes it from the other species of tannic acid, as they do not yield pyrogallic acid when subjected to the same treatment. The following formula will show the relation existing between gallo-tannic acid, gallic acid, and pyrogallic acid. C'^H--0*^ + lOHO = 3(3HO' C'H'O') + C"H'=0'-, 2 aq. Gallo-taaaic acid. Galic acid. Glucose. 3H0, C»H'0' = C'lPO" -t- 2C0* <3allic acid. Pj-rosallic acid. When powdered nut-galls are made into a paste, with water, and allowed to ferment for some considerable time, with occasional stirring to facilitate the absorption of oxygen, the gallo-tannic acid is almost entirely converted into gallic acid. 1 eq. tannic acid C"H"0'^ ) ( 3 eq. gallic acid C'-IP'O^ \ = \ -1 eq. water II' 0* 24 eq. oxygen 0"*) ( 12 eq. carbonic acid C'- 0"* TAN'yiN'G. There have been several patents for quickening the tanning process, but we shall mention only one or two here. The following is taken from the Bavarian Journal of Arts and Trades, and is known as Knodcrer's tanning- process. It is well known that the absence of atmospheric air greatly facilitates the process of tanning, and in order to effect this the process must be carried on in vacuo. The vessel, in which the tanning substance is kept, has to be made air-tight, and at the same time no metal can be used but the expensive one, copper. Iron, :us well a.s zinc, is aflfected by the tanning substance, and wood can only be used when its pores have been stopped by some varnish which elfectually prevents the passage of air into the vessel. The process is carried on as follows: — When the hides are taken from the wash, all the water contained in them is expelled by a powciful press. They are then |)laccd in a barrel, having a rotatory motion, together with the necessary amount of tanning material, and enough water added to keep the contents of the barrel moist. The man-hole is now clo.sed, and the air pumped out as completely as possible ; this being done, the stop-cock is closcii, and a piece of lead pipe is added to the conducting tube ; this lead i)ipe communicates with a tank which contains tanning fluid of proper strength. 1044 TANNING. If the stop-cock !g now opened, the tanning fluid rushes rapidly into the barrel, and when a sutlicient quantity has. been admitted, the stop-cocli; is closed, and the barrel is now rotated for an hour, or half an hour, according to the quantity of hides contained in it. After two or three hours' rest, the rotation is again continued to the end of the operation. The advantages of this process are : First, by the air being rarefied the pores of the skins are opened, and thus more rapidly absorb the tanning principle ; and the tannic acid is not so rapidly converted into gallic acid, which is of no use in tanning. Secondly, the rotatory motion facilitates the extraction of the tannic acid from the bark &c. Thus the hides are completely tanned in a much less time than without rotatory mo- tion, as will be seen by the following table, based on actual experiments. Time required for tanning, Time required when in vacuo, without motion. motion is employed. Calf skins - - from 6 to 1 1 days. • - 4 to 7 days. Horse hides - - 35 40 - - 14 18 Light cow hides - 30 35 --1216 Cow bides (middling) 40 45 - - 18 20 Heavy cow hides - 50 60 - - 22 SO Ox hides (light) - 50 60 - - 20 SO Ox hides (first quality) 70 90 - - 35 40 At the same time a large percentage of bark is saved. A patent was taken out by E. Welsford, of Bona, Algeria, in 1859. Instead of employ- ing oak bark or the ordinary tanning substances, he uses the leaves of the different trees and shrubs of the femily Tcrebinthacece, as the Pistacea tcrebinthus, Pi.stacca Atlantica, Pistacea lentixcus, &c., abounding on the coast of the Mediterranean and clsewher.e. He forms an infusion or decoction of the leaves for tanning. A machine has been invented by Mr. S. F. Cox, of Bristol, for effecting the various pro- cesses of depiling, scudding, striking, smoothing, sticking, and stretching, which are now usually effected by hand. The hide or skin is carried by a cylinder or roller, or by a mov- ing bed or platform, which presents it gradually to a revolving spiral bar rib knife or rubber. The spiral consists of a right and left handed screw, so arranged as to rub or scrape the hide, &c. from the centre toward the sides, or it may consist of a single thread of a screw, or several. The roller or bed which carries the hide or skin is pressed toward the revolving spiral instruments by springs or otherwise, and is gradually advanced by a ratchet, so that the whole of the hide is uniformly and successively exposed to the action of the revolving spiral instruments. A treadle is employed for withdrawing the roller or bed from the revolving spiral to facilitate the adjustment of the hide. Vegetable Substances used in Tanning. No two substances will produce the same quality leather, either in texture or color. Doubtless this is owing to a different variety of tannic acid contained in the material, though unfortunately very little is understood about it, the subject not having been much studied. Some things contain a large proportion of tannin but do not fill up the pores of the hide ; gambir, for instance, tans quickly, but 'does not make a heavy leather. Oak bark, {Qncrcus pedunculata.) — This bark is preferred to all other materials for tan- ning, since it produces the best leather for most purposes. The oak bark of this country is considered superior to that of any other part of Europe. The bark season in England is usually from the middle of April to the end of May. It is essential that the sap should run well before the bark is stripped, as it contains most tannin when the sap begins to run. Enc/lixh coppice oak bark. — This bark is very similar to timber oak bark, Ijut is lighter and thinner, and contains more tannin, as there is not so much epidermis, (which contains none.) It is preferred for tanning light goods. Coppice bark is stripped at the same time of year as the heavier sorts. Belcjium oak bark. — This bark is similar to the English, and is imported, chopped into small pieces, chiefly from Antwerp ; it docs not sell for so high a price as the English, for it is said not to contain so much tannin. Chopped bark is simply bark with the rough epidermis scraped off and then chopped into pieces. Cork-tree bark, [Qiiercus subcr.) — This is the inner bark of the cork tree, the cork gi'ow- ing on the exterior contains no tannin. If is imported from the Island of Sardinia, Tuscany, and the coast of Africa ; the Sardinian is the best, and may easily be distinguished by its color and weight, being of a pinkish hue throughout, and is stouter and heavier than the Tuscan or African. Cork-tree bark contains a great deal of tannin, but deposits little " bloom" cm the leather. There are four species of oak chiefly used for tanning in America. Spanish oak bark is thick, black, and deeply furrowed, and is preferred for coarse leather. In the Southern States the Spanish oak grows to the height of 80 feet with a diameter of 4 or 5 feet at the trunk, wliile in the North it does not exceed the height of 30 feet. TEA, 1045 The common red oak, abundant in Canada and in the Northern States, is very generally employed, though inferior in several respects to the other kinds. 2'Ae rock chestnut oak abounds in elevated districts. On some of the Alleghany moun- tains it constitutes nine-tenths of the forest growth ; its bark is thick, hard, and deeply fur- rowed, but only the bark of the small branches and young trees is used in tanning. Quercitron hark,{Qurrcuii thicloria,) or black oak, grows through th-^ States; its bark is not very thick, l)ut deeply furrowed, and of a deep brown color ; the leather tanned with it is apt to tinge the stockings yellow. This tree often attains a height of 90 feet, and a diameter of 4 or 5 feet. There are other varieties used, but it is needless to mention them here. Valonia, {Quercus cEjrtVops.)— Valouia is the acorn cup of the Quercus cegilops. Sec Leather. Sumac of commerce is the crushed or ground leaves of lihus corriaria, and is imported from Sicily. In making the usual ground sumac the larger branches or sticks are taken out by hand ; the smaller ones do not pulverize, and are taken out by sifting, the stem of the leaves are put under the mill a second time. In grinding, the calculation is that 333 lbs. of leaves turn out 280 lbs. of fine ground sumac. There is naturally, or at least unavoidably, from 3 to 4 per cent, of sand or dirt in the leaves as sent to the mill ; this can only be taken out before grinding, but if thoroughly done would cost Is. 6(7. per cwt. additional, which the trade will not pay. Mimosa bark is the bark of a tree belonging to the order Fabacew, subdivision Mimosce. It is imported from Australia and Tasmania, but is also abundant in the East Indies. Mi- mosa bark is difificult to grind, it is also difficult to extract the tannin; it deposits no bloom, and is, therefore, not much esteemed by English tanners, but is used in the East Indies to a large extent. Gambir, or terra japonica. — This astringent substance, sometimes called catechu, is produced by boiling and evaporating the brown hard wood of the acacia catechu in water, until the inspissated juice has acquired a proper consistency ; the liquor is then strained, and soon coagulates into a mass. It is frequently mixed with sand and other impurities, has little smell, but a sweet as- tringent taste in the mouth, and is gritty if it is perfectly pure ; it will totally dissolve in water, and the impurities will fall to the bottom. It is chiefly used in England as in the East Indies (whence it is imported) for tanning kips. It is mixed with valonia and sumac. Larch bark is used for tanning basils (sheepskins) for bookbinding, &c., principally in Scotland, where the bark is more abundant, though it is also used in England and Ireland. Birch bark is used for tanning Russia leather ; it is also used by the Laplanders. Hemlock bark {Abies Canadensis) is one of the principal barks used in America for tanning ; it makes a reddish colored leather, and not nearly so good as oak bark leather. There is a large collection of tanning materials in the Museum at the Royal Gardens at Kew, collected by Mr. W. G. Fry of Bristol, to whom we are indebted for the practical part of this paper. — H. K. B. TARE, or VETCH, a plant — Vicia saliva — which has been cultivated in this country from the earliest times. TARTRATES are bibasic salts composed of tartaric acid and oxidized bases, in equiva- lent proportions. Some of the tartrates are employed in the arts, bitartrate of potash being used as a mordant in dyeing woollen fabrics. Tartrate of chromium is sometimes used in calico printing, and the tartrate of potash and tin in wool dyeing. The Stockholm tar is regarded as the ))est ; we have a description of the mode in which it is prepared, by Dr. Clai'ke, in his Travels in Scandinavia. " The situation most favorable to the process is in a forest near to a marsh or bog, be- cause tiie roots of the fir, from which tar is principally extracted, are always most produc- tive in such places. A conical cavity is then made in the ground, (generally on the side of a bank or sloi)ing hill,) and tlie roots of the fir, togethei' witli logs and billets of the same, being neatly trussed in a stack of the same conical shape, aio let into the cavity. The whole is then covered with turf to prevent the volatile parts from l)eing di8sii)ated, wiiich, by means of a heavy wooden mallet and wooden stamper, woiked separately by two men, is beaten down and reudei'ed as firm as possible about the wood. Tiie stack of billets is then kindled, and a slow comliustion of the fir takes place as in working charcoal. During this combustion the tar exudes, and a cast-iron \ym\ lieing at the bottom of the funnel, with a spout whicli projects through tlie side of the liank, barrels are placed beneatii this spout to collect the fluid as it comes away. As fast as the barrels are filled they are bunged and ready for immediate exportation. Wood tar is obtained as a secondary product in the manufacture of acetic acid, in the dry distillation of wood. TEA. The observations of Liebig aflord a satisfactory explanation of the cause of the great partiality of the poor, not only for tea, but for tea of an expensive and su])erior kind, lie !-ays : " We shall never certainly be ulile to discover how men were first led to the use 10i6 TENT. of the hot infusion of the leaves of a certain shrub, (tea,) or of a decoction of certain roasted seeds, (coffee.) Some cause there must be which will explain how the practice has become a necessary of life to all nations. But it is still more remarkable, that the beneficial effects of both plants on the hcaltli must be ascribed to one and the same substance, {theine or caffe- ine,) the presence of wliich in two vegetables, belonging to natural families, the products of different quarters of the globe, could hardly have presented itself to the boldest imagination. Yet recent researches have shown, in such a manner as to exclude all doubt, that theine and caffeine are in all respects identical." And he adds, " That we may consider these vegeta- ble compounds, so remarkable for their action on the brain, and the substance of the oigans of motion, as elements of food for organs as yet unknown, which are destined to convert the blood into nervous substance, and thus recruit the energy of the moving and thinking faculties." Such a discovery gives great importance to tea and coffee, in a physiological and medical point of view. At a meeting of the Academy of Sciences, in Paris, lately held, M, Peligot read a paper on the Chemical Combinations of Tea. He stated, that tea contained epsential principles of nutrition, far exceeding in importance its stimulating properties : and showed that tea is, in every respect, one of the mo.st desirable articles of general use. One of his experiments on the nutritious qualities of tea, as compared with those of soup, was decidedly in favor of the former. TEXT. "We have no space to enter into the history of tents, or describe the varieties which have been used from time to time. A few words on modern tents must suffice : — 'J'lic hospital tnnrqnee is 29 feet long, and 14^ feet wide and 15 feet liigh. This is sup- posed to accommodate not less than eighteen nor more than twenty-four men. The height of each tent pole is 13 feet 8 inches; the length of the ridgepole, 13 feet 10 inches; the height of the tent walls from the ground, 5 feet 4 inches. The weight of all the material of such a tent is stated by Slajor Rhodes to be 652 lbs. Of the circular siufile-poleJ tents we have two kinds, the new cotton circular tent, and the new pattern linen circular tent ; each tent is provided with a vertical circular wall ; that of the cotton tent is 2 feet 6 inches in height, and that of the linen tent is 1 foot. The diameter of each tent is 12 feet C inches; the length of the pole about 10 feet. Such a tent accommodates sixteen men. Major Godfrey Rhodes has introduced a new and improved tent, which has no centre- pole. The frame of the tent is formed of stout ribs of ash, bamboo, or other flexible ma- terial. The endrz of the ribs are inserted into a wooden head, fitted with iron sockets, and tiic butts are thrust into the ground, passing through a double twisted rope, having fixed loops at equal distances. The canvas is thrown over this frame-work, and secured within the tent by leather straps to the ground, or circular rope. The present hospital tent, when pitched, covers about 340 square yards. Major Rhodes' hospital tent covers only 03 square yards, and weighs 395 lbs., while it accommodates an equal number of men. The field tent is made up in one package, 5 feet B inches long, weighing 100 lbs. ; the guard tent into one package, 7 feet 6 inches long, weighing 52 lbs. The accompanying cuts, Jir/s. 046 and 647, C46 TENT. 1047 show Major Rhodes' field tent and the frame thereof. The difference, as it regards weiglit and convenience, in those tents introduced by Major Rhodes, is very great. We regret our " space will not admit of more detail ; this, however, is somewhat compensated by the ample detail to be found in a book, Tents and Tent Life, published by the patentee. The ventilation of tents has been admirably effected by Mr. Doyle, to whom we are m- debted for the information contained in the following notes on the subicct :— The old method of ventilating military tents was very defective. Vent.latmg opemngs were made at the top of the tent, but no means were provided for the admission of fresh air. The result was mo.st unsatisfactory, as may be gathered from the following evidence given before the Sebastopol committee : — , i • ^ .t " The tents were very close indeed at night. When the tent was closed in wet weather, it was often past bearing. The men became faint from heat and closeness. * Evidence of Sergeant Dawson. Grenadier Guiirds. 1048 TERRA COTTA. The problem then was to let in fresh air, and produce a draft without inconveniencing the soldiers as they slept. The question attracted Mr. Doyle's notice during the period of the cafap at Chobham, ' and it appearing to him to be one of very great importance, he undertook, with the sanction of Lord llaglan, then Master-General of the Ordnance, to try the following experiment : — lie caused two openings to be made in the wall of a tent, about 6"^^ a/ 4 feet from the ground, and introduced the air between the wall and / a piece of lining somewhat resembling a carriage pocket, fy. 648 : / a a, is the wall of the tent ; 6, the opening to admit air ; c, the lining. / -^ It will be seen that air so introduced would naturally take an up- / ,''' ward direction, and that this communicating with the openings at / ,/ the top of the tent, would probably produce the desired effect. / /' The following extract from the report on this experiment will / ,/ show the actual result : — ^k/ / " The ventilators (Mr. Doyle's) were found of great use in clear- i^2-'' ing the tent of the fetid atmosphere consequent upon a number of tt/ men sleeping in so confined a space. The men state that the heavy smell experienced before the tent was altered is almost banished." In subsequent experiments the number of the new openings was increased from two to three, and a greater amount of ventilation thus obtained. The result, according to an offi- cial letter of thanks received on the subject, was " quite successful." The imjiiovement has been since adopted into the service, and by these very simple means one of the most fruit- ful causes of sickness among our soldiers in camp finally removed. TERRA-COTTA. When moulding is performed for terra-cotta works, sheets of clay are beaten on a bench to the consistency of glazier's putty, and pressed by the hand into the mould ; according to the magnitude of the work and the weight it may hava to sustain, the thickness of the clay is determined and arranged, and here consists a part of the art it would be impossible to describe, and which requires years of experience in such works to produce great works and fire them with certainty of success. At the Crystal Palace, Syden- ham, are several large works manufactured by Mr. J. M. Blashfield, who has extensive terra- cotta works at Stamford. The figure of Australia, modelled by John Bele, nine feet in height, and burnt in one piece ; the colossal Tritons modelled by the same artist, and other works, are examples. After the moulded article has become sufficiently dry, it is conveyed to a kiln. A slow fire is first made, and Cjuickened until the heat is sufficient to blend and partially vitrify the material of which the mass is composed ; when sufficiently baked, the kiln is allowed to cool, and the terra-cotta is withdrawn. TESSER.E. The Roman tessera^, of which many very fine examples have been discov- ered in this country, were, often, natural stones, (sometimes colored artificially,) but gen- erally of baked clay. The beauty of many of these has led to the production of modcrji imitations, which have been gradually improved, until, in the final result, they far exceed any work of the Romans. About half a century since Mr. C. "^^^yatt obtained a patent for a mode of imitating tes- selatcd pavements, by inlaying stone with colored cements. Terra-cotta, inlaid with colored cements, has also been employed, but with no very marked success. Mr. IBIashfield produced imitations of those pavements, by coloring cements with the metallic oxides : these stood exceedingly well when under cover, but they did not endure the winter frosts, &-c. Bitumen, colored with metallic oxides, was also employed by Mr. Blashfield. In 1839 Mr. Singer, of Vauxhall, introduced a mode of forming tesserfe from thin layers of clay. These vrere cut into the required forms, dried and baked. In 1840 Mr. Prosser, of Birmingham, discovered that if the material of porcelain (cliina clay) be reduced to a dry powder, and in that state be compressed between steel dies, the powder is condensed into about a fourth of its bulk, and is converted into a compact solid substance of extraordinary hardness and density. This process was first applied to the manufacture of buttons, but was eventually taken up by Mr. Minton and, in conjunction with Mr. Blashfield, Messrs. Wyatt, Parker «t Co., was carried to a high degree of perfection for making tesserae. The new process, invented by Mr. Prosser, avoided the difficulty altogether of using wet clay. This change in the order of the potter's operations, although very simple in idea, (and a sufficiently obvious result of reflection on the difficulties attending the usual course of pro- cedure,) lias nevertheless required a long series of careful experiments to find out the means of rendering it available in practice. The power which the hand of the potter has exercised over his clay has been proverbial from time immemorial, but it is limited to clay in its moist or plastic state ; and clay in its powdered state is an untractable material, requiring very exact and powerful machinery to W Fubstitutod for the hand of the potter ; in order, by great pressure, to obtain the requi- siti' ( olicsion of the particles of clay. TESSEE^. 1049 In the new process, the clay, or earthy material, after being prepared in the usual man- ner, and brought to tlie plastic state, as above described, (except tliat no kneading or tem- pering is requisite,) is formed into lumps, which are dried until tlie water is evaporated from the clay. The lumps of dried clay are then broken into pieces, small enough to be ground by a suitable mill into a state of powder, which is afterward sifted, in order to separate all coarse grains and obtain a fine powder, which it is desirable should consist of particles of uniform size as nearly as can be obtained. The powder, so prepared, is the state in which the clay is ready for being moulded into the form of the intended article by the new process. The machine and mould used for moulding articles of a small size, in powdered clay, are represented in the annexed drawing, wherein fig. 649 is a lateral elevation of the whole machine. A A is the wooden bench or table whereon the whole is fixed, that bench being sustained on legs standing on the floor, b d e is the frame, formed in one piece of cast iron ; the base B standing on the bench, and being fixed thereto by screw bolts ; the upright stand- ard D rising from the base, and sustaining at its upper end the boss e, wherein the nut or box a is fixed for the reception of the vertical screw f The screw f works through the 649 r \ box a, and has a handle, G, g, li, applied on the upper end of the screw ; the handle is bent downward at g, to bring the actual handle /; to a suitable height for the person who works that machine to grasp the handle h in his right hand, and, by pulling the handle h 1050 TESSERA. toward him, the screw f is turned round in its box, a, and descends. The lower end of the screw f is connected with a square vertical slider, h, which is fitted into a socket, i, fixed to the upiiglit part D of the frame, and the slider ii is thereby confined to move up or down, with an exactly vertical motion, when it is actuated by the screw, without devia- tion from the vertical. Thus far the machine is an ordinary screw press, such as is commonly used for cutting and compressing metals for various purposes. The tools with which the press is furnished for the purpose of this new process consist of a hollow mould, e c, formed of steel, the ex- terior cavity of the mould being the exact size of the article which is to be moulded. The mould c e is firmly fixed on the base d of the frame, so as to be exactly beneath the lower end of the piston, a, or plug, /, which is fastened to the lower end of the square slider h, and the plug / is adapted to descend into the hollow of the mould e e, when the slider h is forced downward by action of the screw f, the plug f being very exactly fitted to the interior of the mould e e. The bottom of the mould e e is a movable piece, n, which is exactly fitted into the interior of the mould, but which lies at rest in the bottom of the mould e e, during the operation of moulding the article therein ; but afterward the movable bottom ii can be raised up by pressing one foot upon one end, r, of a pedal lever, r s, the fulcrum of which is a centre pin, r, supported in a standard resting upon the floor, and the end s of the lever operates on an upright rod, in, which is attached at its upper end to the movable bot- tom 71 of the mould e e. A small horizontal table, T T, is fixed round the mould e c, and on that table a quantity of powdered clay is laid in a lump in readiness for filling the mould. The two detached figures, marked Ji(/s. 650 and 651, are sections of the mould e e, and the plug /, on a larger scale than fff. 049, in order to exhibit their action more com- pletely. The operation is extremely simple ; the operator, holding the handle h with his right hand, puts it back from him, so as to turn back the screw f, and raise the slider h, and the plug /, quite out of the mould e e, and clear above the orifice of the mould, as shown in Jiff. 019. Then with a spatula of bone, held in the left hand, a small quantity of the powder is moved laterally from the heap, along the surface of the table x t, toward the mould e e, and gathered into the hollow of the mould with a quiet motion, so as to fill that hollow very completely, and by scraping the spatula evenly across over the top of the mould e e, the superfluous powder will be removed, leaving the hollow cavity of the mould exactly filled with the powder in a loose state, and neither more nor less than filled. Then the handle //, being drawn forward with a gentle movement of the right hand, it turns the screw f, so as to bring the slider n, and the plug /, which thereby descends into the mould e e, upon the loose powder wherewith the mould has been filled, and begins to press down that powder, which must be done with a gentle motion without any jerk, in order to allow the air that is contained in the loose powder to make its escape ; but the pressure, after having been commenced gradually, is continued and augmented to a great force, by pulling the handle strongly at the last, so as to compress the earthy jnaterial down upon the bottom n of the mould, into about one third the space it had occupied when it was in the state of loose powder. The section, jig. 050, shows this state of. the mould e e, and the plug /, and the compressed material. Then the handle h is put backward again, so as to turn back the screw f, and raise up the slider h, and the plug /, until the latter is drawn up out of the mould e c, and clear above the orifice of the mould, as in fir/. 049, and immediately afterward by jn-cssure of one foot on the pedal u of the pedal lever R, S, and by action of the right rod in, the mov- able bottom n of the mould is raised upward in the mould e e, so as to elevate the com- pressed material which is resting upon the bottom n, and carry the same upward, quite out of the mould e e, and above the orifice of the mould, as is shown in Jig. 651, and then the compressed material can be removed by the finger and thumb. The compressed material which is so withdrawn is a solid body, retaining the exact shape and size of the interior cavity of the mould, and possessing sufiicient coherence to enable it to endure as much handling as is requisite for putting a number of them into an earthen- ware case or pan, called a sagger, in which they are to be enclosed, according to the usual practice of potters, in preparation for putting them into the potter's kiln for firing ; the sag- ger protects tlie articles from discoloration by smoke, and frotn partial action of the flame, which, if a number of small articles were exposed thereto, without being so enclosed, might operate more strongly upon some than upon others of those articles ; but by means of the snggcrs the heat is caused to operate with clearness, uniformity, and certainty upon a num- ber of small articles at once. After the firing is over, the articles, being removed from the saggers, are in the state of what is termed biscuit, and are ready for use, unless they are required to be glazed, in which case they may be dipped into a semi-liquid composition of siliceous and other matters, ground TIN PLATES. 1051 ia water to the consistency of cream, and the surface of the articles which are so dipped becomes covered with a thin coating of the glazed composition, and then the articles are again put into saggers, and subjected to a second operation of firing in another kiln, the heat whereof vitrities the composition and gives a glassy surface to the articles, all which is the usual course of making glazed eartlienware or porcelain ; but for articles formed by the new process, a suitable glazing composition is more usually applied within the saggers, into which the articles are put' for the first firing, and the glazing is performed at the same time with the first burning, without any other burning being required. Or, in other cases, the composition of earthy materials which is chosen for the articles may be such as will become partially vitrified by the heat to which they are exposed in the kiln, and thereby external glazing is rendered unnecessary. The great contraction whicla must take place in drying articles which have been moulded from clay in the moist state is altogether prevented, and consequently all uncertainty in the extent of that contraction is avoided. Tiles, tesserse, and other articles are now made by this machine ; and very beautiful pavements are constructed, excelling the finest works of the Romans in form, in color, and in all the mechanical conditions. THEBAIXE. C^'H^'XO-. One of the numerous alkaloids contained in opium. THIALDIXE. C'-H"XS'. A curious alkaloid, formed by the action of sulphuretted hydrogen on aldehvde ammonia. THORIXUM OR THORIUM. A rare metal found in the mineral thorite which con- tains about 57 per cent, of thorina, the oxide of this metal. TIN PLATES. The affinity of iron for tin is much greater than is generally supposed. The point at which the metals cohere is no doubt an actual alloy ; and advantage is taken of this by the manufacturers of articles for domestic use, male in iron — as bridle bits, com- mon stirrups, small nails, &c. When the imii, whether wroi rht or cast, is perfectly clean and free from rust, and brought in contact with melted tin, at a high temperature, an alloy seems to be at once formed, protecting the iron from oxidization whilst the tin lasts. Many plans are used for tinning iron articles, of small size, by the manufacturers. One of the common methods of manufacturers of bridle bits and small ware, in South Staffordshire, is to clean the surface of the articles to be tinned, by steeping them for sufficient time in a mixture of sulphuric and hydrochloric acids, diluted- with water, then washing them well with water, but taking great care they do not rust, at once placing them in a partially closed stoneware vessel, (such as a common bottle,) which contains a mixture of tin and hydro- chlorate of ammonia. This vessel is then placed on a smith's hearth, duly heated, and fre- quently agitated to sqcurc the complete distribution of the tin over the iron. The articles, when thus tinned, are thrown into water to wash away all remains of the sal ammoniac ; and lastly, cleaned in hot bran, or sawdust, to improve the appearance for sale. The plans of cleaning and preparing the iron for tinning have undergone many changes in the past century. About 1720 the plan for cleaning was to scour the plates with sand and water, and file off the rough parts, then cover with resin, and dip them in the melted tin. About 1747 the plates were, after being cold rolled, soaked for a week in the lees of bran, which had been allowed to stand in water about ten days, to become, by fermentation, sufficiently acid, and then scoured with sand and water. In 1760 the plates were pickled in dilute hydrochloric acid before annealing, and cleaned with dilute sulphuric acid after being taken out of the bran lees. An improvement of great importance in this process was made about 1715 ; the inventor seems to have been Mr. Mosely, who carried on tin plate works in South Staffbrdshire. This invention was the use of the grease pot, and in this department little, if any, improvement has since been made. The plan was introduced into South Wales in 1717 by Mr. John Jenkins, and his descendants are still amongst the principal manuf\ic- turers in the trade. The process of cleaning and tinning at some of the best works now is as follows : — When the sheet iron leaves the plate mill, and after separating the plates, and sprinkling between each plate a little sawdust, the effect of which is to keep them separate, they are then immersed, or, as technically termed, " pickled," in dilute sulphuric acid, and after this placed in the annealing pot, and left in the furnace about 24 liours ; on coming out, the plates are p;issed through the cold rolls ; after passing the cold rollsi, the plates seem to have too much the character of steel, and are not sufficiently ductile ; to remedy this they are again annealed at a low heat, washed in dilute sulphuric acid, to remove any scale of oxide of iron, and scoured with sand and water; the plates in this state require to be perfectly clean and bright, and may be left for months immei-sed in pure water without rust or injury ; but a few minutes' exposure to the air rusts them. With great care to have them perfectly clean, they are taken to the stow, 777. 652, being a section through the line K K of the plan firi. 653. Taken from right to left. 1 represents the Tinman's pan. 2 " the Tin pot 3 " the Washing or dipping pot. The tinman's pan is full of melted grea.^e : in this the plates are immersed, and left there until all aqueous moisture upon them is evaporated, and they arc con-plctclv covered wit' 4 represents the Grease pot. 5 " the Cold pot. 6 " the List pot. 1052 TIN PLATES. 652 ^t^_^ "Tl"! G53 i^-- .->K-- tip 1 It i; t t 11^ t^T the grease ; from this they are taken to the tin pot, and there phmged into a bath of melted tin, which is covered with grease ; but as in this first dipping the alloy is imperfect, and the surface not uniformly covered, the plates are removed to the dipping or wash pot ; this con- tains a bath of melted tin covered with grease, and is divided into two compartments. In the larger compartments the plates are plunged, and left sufficiently long to make the alloy complete, and to separate any superfluous tin which may have adhered to the surface ; the workman takes the plate and places it on the table marked b on the plan, and wipes it on both sides with a brush of hemp ; then to take away the marks of the brush, and give a polish to the surface, he dips it in the second compartment of the washpot. This last always contains the purest tin, and as it becomes alloyed with the iron it is removed on to the first compartment, and after to the tin pot. The plate is now removed to the grease pot (No. 4) : this is filled with m.elted grease, and requires very skilful management as to the tempera- ture it is to be kept at. The true object is to allow any superfluous tin to run off, and to prevent the alloy on the surface of the iron plate cooling quicker than the iron. If this were neglected the face of the plate would be cracked. The plate is removed to the cold pot (No. 5) : this is filled with tallow, heated to a comparatively low temperature. The use of the grease pots, Nos. 4 and 5, is the process adopted in practice for annealing the alloyed plates. The list pot (No. 6) is used for the purpose of removing a small wire of tin, which adheres to the lower edge of the plate in all the foregoing processes. It is a small cast-iron bath, kept at a sufficiently high ten,perature, and covered with tin about one fourth of an inch deep. In this the edges of the, plates are dipped, and left until the wire of tin is melted, and then detached by a quick blow on the plate with a stick. The plates are now carefully cleaned with bran to free them from grease. Lastly, they are taken to the sorting room, where every plate is separately examined and classed, and packed in boxes for market as hereafter described. The tests of quality for tin plates are — ductility, strength, and color. To obtain these, the iron must be of the best quality, and the manufacture must be conducted with propor- tionate skill. This necessity will explain to som.e extent the cause why nearly all the im- provements in working iron during the past century lave been eitlicr originated or first adopted by the tin-plate makers ; and a sketch of the processes used at difterent times, in working iron for tin plates, will be, in fact, a history of the trade. The process of preparing the best or charcoal iron seems to have undergone but little change from 1720 to 1607. The finery, the chaferv, and the hammer were the modes of bringing the iron from the pig to the state of fini-shed bars. The finery was of the exact form of the ffi^. 054, 655, 650, but less in size than those now used. The chafery or hollow fire was, in fact, the same as the present smitlis' forge fire, but on a larger scale ; and the "/(o//o?/t" or chamber, in which the bloom was heated, was made by coking the coal in the centre with the blast, and taking care not to disturb the mass of coal above, which was used to reverberate the heat produced. Both the finery and chafery were worked by blast. The hammers were of two descriptions : the forge hammer, a heavy mass for shaping the blooms, and the tilt hammer, much lighter and driven quicker, for shaping the bars. The charge for the finery was about 1 i cwt. of pig iron : this, under the first process, was nducccl to \\ cwt. It was, when ready, put under the forge hammer, and shaped into TIN PLATES. 1053 a " bloom," about 2 feet long and 5 inches thick ; this was then heated in the chafery, and under the tilt hammer drawn out to a " bar," 3 to 4 inches wide, and half inch thick. 65^ pv-rr- The manufacture up to this point, until a recent period, was carried on by the iron masters, and the iron in this state was sold under the name of " tin bars " to the plate makers. The average price for these bars, from 1780 to 1810, was £21 per ton. The sheet and cold rolls were then in use nearly .is at the present time In 1807, Mr. Watkin George, whose position had been established as one of the first engineers of his time, by the erection of the great water wheel and works at Cyfarthfa, removed to Pontypool, and undertook the remodelling of the old works there. He clearly 657 656 r \ \ U L_L I I \ saw that the secret of the manufacture was to produce the largest possible quan- tity with the least possible machinery and labor. His inventions, to this end, worked a complete change in the trade. His plans were : to first reduce the pig iron in a finery under coke, and then bring tliis " refiners' metal " (so termed) into the charcoal finery. The charcoal finery was ))uilt as shown mfigs. 654, 655, and 656 ; fiij. 654 being a front elevation, fig. 655 a horizontal, and fig. 656 a vertical section. A charge of 3 cwt. of iron was used in this, and as it became malleable it was reduced under the hammer to what he termed a " stamp : " this was a piece of iron about 1 inch thick, and of any shape horizontally. It was next broken in pieces of a convenient size, and about 84 lbs. were " piled" on a flat piece of tilted iron, with a handle about 4 feet long. This rough shovel, or holder, was called 1054 TIN PLATES. the " portal," or the " staff." To reheat this " pile " in the chafery would be a work of great cost and difficulty, and the brick hollow fire (as shown in fgs. 657, 658, 659, 660, 661, and 662 ; fgs. 657 and 658 being elevations, and fgs. 659, 660, 661, and 662 sec- tions) was invented. This is, the writer believes, one of the inventions which, although •660 in work during the past fifty years, still points to very great improvements in the manufac- ture of iron. It is in substance the plan of using the gases produced by the decomposition of fuel for the working of iron. The charcoal fnery is also worked by the use of the gases to a much greater extent than is generally known. The workman sends his blast directly into the mass of iron, and the charcoal seems to be simply the means by which he is better enabled to manipulate the iron in the finery, and keep it covered, so as to revive the oxidized metal, and thus prevent waste. A few hours spent with any intelligent workman at the side of his charcoal finery would show the wasteful and expensive character of the so-called 7icw schemes for con- TIN PLATES. 1055 662 verting cast into wrought iron by the use of air alone. The hite belief in these schemes, by men of high repute and practical knowledge in the trade, is a direct proof of the deficiency in knowledge of esact science, as at pres- ent applied to the nianuf\xcture of iron. The pile was now placed in the hol- low fire, and brought to a soft welding or washing heat — again hammered out to " slabs," 6 inches wide and three quarters inch thick ; these were re- heated, cut up, and afterward passed through rolls, reducing them to " bars" 6 inches by half inch. These were known in the trade as " hollow fire iron" or "tin bars." The result of Mr. Watkin George's improvements was to reduce the cost and double the production with the same outlay in machinery. All the tin plates made at this time had the great defect of a rougii and smooth side. In the year 1820, Mr. Win. Daniell (a gentleman siill living, and for whose invention the trade is and will be under great obligation) found a mode to remedy this defect. Himself a maker of tin bars and plates, he had observed that the smooth side of the plate was al- w;iys that corresponding to the flat part of the " portal," or " staff'; " be at once, having ascertained this cause, remedied the defect by hammering out the pile, notching it, and doubling it over, so that the tilted blade of the " staff" was on the top as well as the bottom of the pile. Tliis was the in- vention of " tops and bottoms," and the writer need not remind practical men of the immense sums made by this discovery during the past thirty- seven years. Another improvement since 180T is tlie use of the running-out fire : it is still adopted in only a fow works. Tiiis is represented by fyx. 003, 004, and 605. fir;. 063 is a front elevation ; Jiff. 604 a horizontal section ; andfr/. 665 a vertical section. This process saves waste of heat and labor, by rim- ning the refined metal at once into the charcufil finery*. p "^~^ K"a " " ls$>-| J# jiF= ■^T s-^-;-^ i jT^ % jpi I 1056 Tlis" PLATES. The "tin bars" before referred to, 6 inches by half inch, are heated and run through roll(?rs until they form a sheet of sufficient width ; this sheet is then doubled and passed through the rolls, and this repeated until this sheet is quadrupled, — the laminae are then cut to size, and separated as before described. The writer asks careful attention to 'the fact that the last part of the rolling is done when the iron is nearly cold. These sheets are next annealed, and were formerly bent separately by hand, into a saddle, forming two sides of a triangle, thus A , and placed in a reverberatory furnace, so that the flame should play amongst them, and heat them to redness ; they were then plunged into a bath of muriatic acid, or sulphuric acid and water, for a few minutes, taken out, and drained on the floor, and again heated in a furnace ; after which, a scale of oxide of iron separates from the plate during the work of bending them again straight, on a cast-iron block. The plates should be now free from rust or scale, and are then passed cold through the chilled rolls ; this last process is most important, as the ductility and the strength and color of the tin plate depend upon this ; at this point bad iron will crack or split, and any want of quality in the iron, or skill in the manufacture, will be shown. A great improvement in the process of annealing was made in 1829 by Mr. Thomas Morgan : the plates were piled on a stand, and covered with a cast-iron box, now termed an " annealing pot ; " in this they were exposed to a dull red heat in a reverberatory furnace 666 for 24 hours. This annealing pot with its stand is represented hj fg. 666, in plan and vertical section. A very important invention in the manufacture of iron for tin plates, and which is yet only partially carried out, was made by Mr. William Daniell in 184.5. About 21 cwt. of reflned metal is placed in the charcoal finery ; this is taken out in one lump, put under the hammer and "nobbled," then passed at once through the balling rolls, and reduced to a bar 6 inches square and about 2 feet 6 inches long. This bar is either cut or sawed off in pieces 6 inches long, and these rolled endways to give a bar about 6 inches wide, 2^ inches thick, and 12 inches long, and in this state the inventor calls it a "billet." This is heated in a small baUing furnace and rolled down to a bar one quarter inch thick and eleven inches wide, and will be about six feet long. This is taken at once to the tin-plate mill, and the process saves great expense in fuel and machinery. By the old method of annealing, a box of tin plates required about 13 lbs. of tin. This is now done with about 9 lbs. for charcoal and 8 lbs. for coke plates. In referring to tin plates the standard for quotation is always taken as 1 C. (Common, Xo. 1.) This is a box containing 2'25 plates, which should weigh exactly 112 lbs. One of the great items of expense in the manufacture of best iron, as before described, is the cost of charcoal for the fineries. This limits at present the production of iron made by these means ; but the superior quality of iron made in the charcoal finery is always ad- mitted. About 1850 the attention of the writer was directed to the use of a substifite for charcoal in the finery. Careful thought and experiment led him to the conclusion that some coals could be charred in such a way as to produce a mechanical structure analogous to charcoal, and at the same time, when deprived of sulphur, might be used in the finery. These experiments resulted in the manufacture of a substance the writer names ^^ charred coaly This material has been worked at several of the principal manufactories in South Wales, and declared equal in every respect to charcoal. Some tin plates made by this process were shown at the Great Exhibition in 1851 ; as also the charred coal used in the finery. (See the Juror^s Reports, dr.) The quality of the plates was admitted as equal to the best charcoal. The preparation of the '■^ charred coaV \s very simple. The coal is first reduced to small, and washed by any of the ordinary means : it is then spread over the bottom of a reverberatory furnace to a depth of about 4 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 light spongy mass which is turned over in the furnace, and drawn in about one hour and a half. To completely clear off the sulphur, water is now freely sprinkled over the mass until all smell of the sulphuretted hydrogen gas produced ceases. The result is " charred coal." The quantities of " charred coal " hitherto produced have been made on the floor of an ordinary TIN PLATES. 1057 coke oven, whilst red hot, after drawing the charge of coke. The following analysis of the coal from which this "charred coal" is made, is extracted from the "Report ou the Coals Suited to the Steam Navy," by Sir H. De la Beche and Dr. Playfair: — Abercarn Coal. Carbon 81-26 Hydrogen 6-31 Nitrogen - -11 Oxygen ...--.. 9'96 Sulphur 1-86 Ash - - 2-04 102-20 Some points of great practical value may be elicited from this description of the manu- facture of iron for tin plates. The stamp iron is highly crystalline, and falls to pieces under the hammer unless cautiously handled. The pile itself, after heating, is also crystalline and brittle ; but after passing through the rolls it becomes less crystalline. When reduced to a sheet it is still less crystalline and more ductile ; but after passing the cold rolls all the crystalline character is apparently destroyed, and it becomes a homogeneous mass, and very ductile, hard, and tough. The hammering and rolling appear to alter the structure of the iron, and, instead of allowing the atoms to arrange themselves in crystals, to bring them into a homogeneous or amorphous mass, which is then held together by the law of cohesion, and is more dense and closer than when crystallized. In practice this principle is constantly used. Every smith knows the practicil result of what is termed " hammer hardening." Tin coating of iron and zi/ic, by Mr. Morries Stirling's patent process. For this pur- pose the sheet, plate, or other form of iron, previously coated with zinc, cither by dipping or by depositing from solutions of zinc, is taken, and after cleaning the surface by washing in acid or otherwise, so as to remove any oxide or foreign matter which would interfere with the perfect and equal adhesion of the more fusible metal or alloy with which it is to be coated, it is dipped into melted tin, or any suitable alloy thereof, in a perfectly fluid state, the surface of which is covered with any suitable material, such as fatty or oily matters, or the chloride of tin, so as to keep the surface of the metal free from oxidation ; and such dipping is to be conclucted in a like manner to the process of making tin plate or of coating iron with zinc. When a fine surface is required, the plates or sheets of iron coated with zinc may be passed between polished rolls (as already described) before and after, or either before or after they are coated with tin or other alloy thereof. It is preferred in all cases to use for tlie coating pure tin of the description known as grain tin. Another part of the invention consists in covering either (wholly or in part) zinc and its alloys with tin, and such of its alloys as are sufficiently fusible. To effect this, the following is the process adopted : — A sheet or plate of zinc (by preference such as has been previous- ly rolled, both on account of its ductility and smoothness) is taken, and after cleaning, its surface by hydrochloric or other acid, or otherwise, it is dried, and then dipped or passed in any convenient manner through the melted tin, or fusible allqy of tin. It is found desirable to heat the zinc, as nearly as may be, to the temperature of the melted metal, previous to dipping it, and to conduct the dipping, or passing through, as rapidly as is con- sistent with thorough coating of the zinc, to prevent as much as possible the zinc becoming alloyed with the tin. It is recommended also that the tin or alloy of tin should not be heat- ed to a higher temperature than is necessary for its proper fluidity. The metal thus coated, if in the form of sheet, plate, or cake, can then be rolled down to the required thickness ; and should the coating of tin or alloy be found insufficient or imperfect, the dipping is to be repeated as above deseril)ed, and the rolling also, if desired, either for smoothing the surface or further reducing the thickness. Another part of the invention consists in coating lead or its alloys with tin or alloys thereof. The process is to be conducted as before described for the coating of zinc, and the surface of lead is to be perfectly clean. The lead may, like the zinc, be dipped more than once, either before or after being reduced in thickness by rolling. Lead and its alloys may also be coated with tin or its alloys of greater fusibility than the metal to be coated, as follows: — The cake, or other form to be coated, is to be placed as soon after casting as may be in an iron, gun metal, or other suitable mould ; or, if this can- not be conveniently done, the surfaces are to be cleansed and prepared for the reception of the coating metal, either ])y previously tinning the surfiice, or by applying other suitable material to facilitate the union, as heretofore practised. At one end of the mould are to be attached chambers, of more than sufficient capacity to contain the quantity of metal to be used for coating, which may with advantage form an integral part of the mould, or such chamber may surround the mould, anil by one or more sluices or valves in such chamber or chambers, th;; melted metal is to ))e allowed to run on to the surface of the metal to be coated, when the metal is to be coated on one side only. When it is intended to coat the metal on both sides, the vertical position will be found convenient, and the coating metal is Vol. III.— (17 1058 TUBES. to be poured into a chamber or chambers attached to the mould, and to be introduced into the lower part of the mould by opening a sluice or valve, sufficient space being left on each side of the cake or other form to allow of the coating being of the required thickness ; the sluice or valve should be of nearly the width or length of the cake or other form, and the melted metal should be allowed to flow into the bottom of the mould. The surface of the plate or cake ought to be smooth and true, and the mould, if horizontal, to be perfectly so, and if upright, quite perpendicular, so as to insure in either case an equal footing. The surface of the lead should also be clean, and it will be found advantageous to raise its tem- perature to a point somewhat approaching the melting point of tin or of the alloy employed for coating, as by this means the union of the two metals is facilitated. It is recommended also, that a somewhat larger quantity of the tin or alloy than is necessary for the coating of the lead or other metal, or alloy, should be employed, and that when the requisite thick- ness of coating has been given, the flow of the coating metal be stopped, as by this means the impurities on the surface of the tin will be prevented passing through the opening on to the surface of the cake : the chamber or chambers should be kept at such temperature as to insure the proper fluidity of the coating metal. Zinc and its alloys may in like manner be coated with tin and its alloys, by employing a like apparatus to that just describ- ed for coating lead and its alloys, and it constitutes a part of this invention thus to coat zinc. The coating of zinc with tin, however, is not claimed, that having been done by pouring on tin. TUBES. The manufacture of iron tubes for gas, water, and other purposes has become one of extreme importance. Mr. Russell of Wednesbury patented a process which has been carried out on a very large scale. In this process plate iron, previously rolled to a proper thickness, is cut into such strips or lengths as may be desirable, and in breadth correspond- ing with the width of the tube intended to be formed. The sides of the metal are then bent up with swages in the usual way, so as to bring the two edges as close as possible together. ^ The iron thus bent is then placed in an air or blast furnace, and brought to a welding heat, in which state it is with- drawn and placed under the hammer. Fig. 667, a, is the anvil having a block or bolster, with a groove suited to and corresponding with a similar groove, b, in the face of the block, c is a wheel with projecting knobs, which, striking in suc- cession upon the iron-shod end of the hammer shaft, causes it to strike rapidly on the tube. In this process the tube is repeatedly heated and hammered, until the welding is complete from end to end. A mandril may be inserted or not dur- ing this operation. When the edges of iron have been thus thoroughly united, the tube is again heated in a furnace, and then passed through a pair of grooved rollers similar to those used in the production of rods. Jig. 668. Sup- pose a tube, D, to be passing through these rollers, of which j?_qr. 669 represents a cross section, immediately upon its being de- livered from the groove it receives an egg-shape core of metal fixed upon the extremity of the rod e, over which the tube sliding on its progress, the inside and outside are per- fected together. Mr. Cort patented a similar process for the manufacture of gun barrels. TUFA. A volcanic product. See Mortar, Hydraulic, vol. ii. TUXGSTEX. (Tunr/sienc, Ft. ; Wolframiian, Germ.) Symbol, Ts or W. Its name is derived from the principal mineral from which it is obtainable. Tungsten, Swedish, fnnrr, heavy, sten, stone, or Wolfram, German. This metal was discovered by the brothers Do Luyart, about 1784, shortly after the discovery of tungstic acid by Scheele, from whom it is sometimes called Scheelium. It is never found in the native state, but is produced by a variety of processes. First, and most easily, by mixing the dried and finely-powdered tungstate or bitungstate of soda with finely-divided charcoal, such as i lampblack, placing tlie mixture in a crucible lined with charcoal, covering it with charcoal in powder, and then exposing the whole to a steady red heat for two or three hours. On removal of the cru- cible and cooling it, a porous mass is found, from which the soda is removed by solution in water, and the unconsumed carbon is separated by washing it off, the metal being left as a bright, glistening, blackish-gray metallic powder. It may also be obtained by treating tungstic acid in a similar manner, or by exposing the acid at a bright red heat, in an iron or glass tube, to a current of hydrogen gas. Tungsten is one of the heaviest metals known. TUNGSTEN". 1059 its specific gravity being 17'22 to 17"6. It requires such a very high temperature for fusion thit it has never yet been obtained in mass; more commonly as a fine powder, but sometimes in small grains. It is not magnetic. It is very hard and brittle. Alone it has not been rendered available for any useful purjiose, but it has lately been employed for the manufacture of certain alloys. Tungsten is comparatively a rare substance, and is remark- able for the very limited extent to which in nature it is found to have been mineralized by combination with other substances. In none of these does it exist as a salifiable base, but as an acid, as in wolfram, Scheelite, yttrolantalite, and the tungstatc of lead. The most common ore of this metal is wolfram, known also to the CornLsh miner as cal or callen, and gossan. It is most commonly found associated with tin ores, which contain besides the black oxide of tin or cassiterite, the metallic minerals, arsenical iron, copper, lead, and zinc sulphides ; but its peculiarly characteristic associate is the metal molybde- imm, for the most pait mineralized as a sulphide. This metal is remarkable in connection with tungsten as producing isoiieric compounds, and as having both its equivalent and its specific gravity equal to about one half that of tungsten, they being respectively as fol- lows: — equivalents, Ts, 9'), Mo, 48; sp. gr. Ts, ltV22, Mo, 8-615. Amongst miners wolfram has the reputation of being an abundant mineral, but on close inquiry it is found to be comparatively rare, scliorl, specular, and other iron ores, and gossan being commonly mistaken for it. From its association with tin ores, it has been until lately the source of great loss to the miner, as it was found quite impossible to sepa- rate it even to a moderate extent from the ore in consequence of its specific gravity, 7"! to 7'4, being so near to that of black tin, 6"3 to 7"0. Pryce, in his Mineralogia Cornubiensis, 1778, says: "After the tin is separated from all other impurities by repeated ablutions, there remains a quantity of this mineral sul)stince, (gal,) which being of equal gravity cannot be separated from the tin ore by water, therefore it impoverishes the metal and reduces its value down to 8 or parts of metal for twenty of mineral, which without its brood, so called, miglit fetch twelve for twenty." This de- scription of tin ores containing wolfram was still applicable until a very recent period, when a new process was invented by Mr. Robert Oxland, of Plymouth, and by him successfully introduced at the Drake AValls Tin Mine, at Gunnis Lake, on tlie banks of the Tamar, where it has been continued in operation ever since. At this mine, although the tin ore raised was of excellent quality, in spite of all that could be done by the old processes, it was left associated with so much wolfram that the ore fetched the lowest price of any mine in Cornwall. At the time of the introduction of the process the greater portion of the ore was sold for £42 per ton. The improvement efTected by it was so great that the same sort of ore sold for £56 per ton. The Drake Walls ores are now known as the best of the mine ores in Cornwall. The process is a neat illustration of the advantages obtainable by the careful direct application of scientific principles, guided by practical experience, to the improvement of the results obtainable by mining operations. The process consists in taking tin ores mixed with wolfram, dressed as completely as possible by the old process, and having ascertained liy analysis tlie quantity of wolfram con- tained therein, then mixing therewith such a quantity of soda ash of known value as shall afford an equivalent of soda for combination with the tungstic acid of the wolfram, which is the tungstate of iron and manganese; the o))ject of the process being by calcination to convert the insoluble tuugstate of iron and manganese into the soluble tungstate of soda, leaving the oxides of iron and manganese in a very finely-divided state and of low specific gravities, so that they can be easily washed off" with water. The mixture, in cliarges of five to ten cwt., is roasted in a reverberatory furnace on a cast-iron bed of the construction siiown in X'/s'- 070 and 671. The 670 use of the cast-iron bed is attended witii considerable economy in the consumption of fuel, and it is ad- mirably well adapted for the calcina- tion of the raw ores, for the evolu- tion of the sulphur and arsenic con- tained in them ; but it is especially necessary instead of fire brick or tile, to avoid the loss which would accrue from the reaction of the soda ash on the silica of the brick, and the formationofsodasilicateof tin which would consequently take place. The mixture is introduced to the bed through a hole in the crown of the fiu-nace ; from a side door it is eciually distributed over the bed. |''//#^# 1060 TURBINE. and from time to time it is turned over by the furnace man until the whole mass is of a dull red heat, emitting a slight hissing sound, and in an incipient pasty condition. In successive quantities the charge is then drawn through a hole in the bed of the furnace into the wrinkle or arch beneath, whence it is re- moved to cisterns, in which it is lixiviated with water, and the tungs- tate of soda is drawn off in solu- tion. The residuary mass left in the cisterns, — the whole of the solu- ble matter having been washed out, — is removed to the burning-house floors, and is there dressed over again in the usual manner, the final product of the operations being very nearly pure black oxide of tin. The liquid obtained is either evaporated sufficiently for crystallization when set aside to cool, or is at once dried down to powder. The crystals of tungstate of soda thus obtained are colorless, translucent, of a beautiful pearly lustre, having the form of rhombic prisms or of four-sided laminae. The composition of the crystallized and of the anhydrous tungstate of soda is as follows : — Anhydrous. Crystalline. 20-63 18-44 Soda - . - Tungstic acid Water - 79-37 •00 70-92 10-64 100-00 100-00 It has been proposed to use this substance as a mordant for dying purposes, as a source of supply of metallic tungsten for the manufacture of alloys, for the manufacture of the tungstates of lime, barytes, and of lead to be used as pigments ; and still more recently it has been found to be valuable, and preferable to any other substance, for rendering frabrics not inflammable, so as to prevent the terrible accidents constantly occurring from the burn- ing of ladies' dresses. For this purpose a patent has lately been obtained by Messrs. Vers- mann and Oppenheim. For the manufacture of metallic alloys a patent has been obtained by Mr. R. Oxland, as a communication from Messrs. Jacob and Koeller. Steel of very superior quality, man- ufactured under this patent, is now coming extensively into use in Germany. It is prepared by simply melting with cast steel, or even with iron only, either metallic tungsten, or prefer- ably, what has been termed the native alloy of tungsten, in the proportion of two to five per cent. The steel obtained works exceedingly well under the hammer. It is very hard and fine grained, and for tenacity and density is superior to any other steel made. The na- tive alloy is obtained by exposing to strong htat in a charcoal-lined crucible a mixture of clean powdered wolfram with fine carbonaceous matter. A black, steel-gray metallic spongy mass is obtained resembling metallic tungsten. The composition of the alloy is shown in the following statement of the composition of wolfram : — Tungstic acid. Oxide of Iron. Oxide of manganese. Tungsten 76-25 Iron 17-75 Manganese 6-00 = 100 Oxygen 19-06 Oxygen 5-07 Oxygen 1-71 = 25-84 125-84 The tungstate of soda is used in dyeing; metallic tungsten, or native alloy, is also used for the manufacture of packfong or Britannia metal, by alloying with copper and tin. By these useful applications this metal has already become a desideratum, which only a few years since was regarded as one of the most deleterious associates of tin ores, and the only one that was perfectly unmanageable. — R. 0. TURBINE. Although the horizontal water wheel has been known and employed under various forms from the highest antiquity, and has latterly been improved by Fourncy- ron, Fontaine, Jouval, and others, so as to rank among the most perfect of hydraulic motors, it has only recently been applied to mining uses, (pumping, loading, &c.,) and where so employed its success can scarcely be said to be yet decided. The failures may be attributed to the following causes. First: The plan of causing the water to flow simultaneously through all the buckets, necessitates the use of wheels of small dimensions, making a very great number of revolutions per minute, and thus requiring a considerable train of inter- mediate gear to reduce the speed to the working rate. Second: The complex nature of TURBINE. 1001 the ring sluices employed between the guide curves and the mouths of the bucket, renders them uncertain in action, and from their small dimensions liable to be easily choked by any mechanical impurities in the water; and lastly, the lubrication of the foot spindle of the vertical wheel, revolving at very great velocity, is attended with considerable difficulty and incouvenience, especially where the engine room is at a considerable distance below the surface of the earth, and it is requisite, as in the case of pumping wheels, to keep the machinery in action continuously for long periods of time. The form of wheel of which a notice is here appended, was introduced into the Saxon mines about the year 1849 by Herr Schwamkrug, inspector of machinery at the Royal Mines and Smelting Works at Frey- berg, and since that time several have been introduced for pumping, winding, driving stampheads, &c. The example selected for illustration was built to take the place of two overshot water-wheels, employed in pumping water at the mine " Churprinz Friedrich Au- gust ; " it differs from the usual form of turbine in having the wheel placW vertically, and in having the water supplied through a small number of guide curves near the lowest part. In this latter respect it resembles the tangential turbine of General Poncelet, with this dif- ference, that the water flows from the inner to the outer circumference, instead of the reverse way, as is the case in Poncelet's wheel. The construction of the wheel is as follows : a^fig. 672, is the tubular axle of cast iron which carries the seating for the arms s, which is 672 similar to that usually used for large water wheels ; to the ends of the arms is attached the wheel ?o, which is formed of two brags or shroudings of sheet iron, each 1" inches deep, measured radially, and of a total height of 10 feet 2 inches ; these two rings are maintained at a distance of inches apart, by means of 44 sheet-iron buckets of the form shown in the smaller detailed figure, ficj. OT^i ; the driving water is admitted thiough the pressure pipe y), in which is placed the admission throttle <, and turned tlirough a pipe of rectangular sec- tion (shown in the smaller figure) into the sluice box .s-, wliich contains tiic two guide curves V, v', wliich arc movable about the centres c, <■', ))y means of the levers /, l\ l>y means of these guide curves when fully oi)encd, as shown in tiie figure ; the water is admitted into the buckets in two parallel streams of jets of 5j- inches in breadth, and I'/iu inches in thickness; the power is transmitted from tlie axle of the wliee! by a pinion with 28 teeth, wliich draws the large toothed wheel x, which acts on a third shaft carrying the pump 1062 TUKKEY RED. cranks. The wheel is constructed to work under a head of 147 feet, and makes about 130 revolutions per minute, with a maximum quantity of 550 cubic feet of water, equal to nearly 175 horse power. A series of dynamomefrieal experiments on a wheel of similar construction of 7 feet 9 inches in diameter, with a discharge varying from 89 to 134 cubic feet, with a head of 103 feet, gave an available duty of from 58 to 79 per cent., the number of revolutions varying from 112 to 148 per minute. In conclusion it may be remarked that the vertical turbine may be employed with advantage where the available fall of water is too great to be employed on a single overshot water-wlieel ; and although a less perfect machine than the water-pressure engine, it is of simpler construction, and may be preferred where, from the hardness or yielding nature of tlie rock, it becomes ditlicult to construct large machine rooms or wheel pits underground. In practice it is found necessary to surround the wheel with a casing of wood, in order to prevent the affiif^nt water being projected to a distance from centrifugal action. TUKKEY RED is the name given to one of the most beautiful and durable of known dyes. The art of dyeing cotton with this color seems to have originated in India. In his Philoaopliy of Permanent Colors^ Bancroft has given a detailed account of the process as practised in that country, and this process will be found to agree in all essential particulars with that pursued by the Turkey-red dyers of Europe, except that in India the chaya root is employeil as the dyeing material in the place of madder. In the middle ages the art was practised in various parts of Turkey and Gicece, especially in the neighborhood of Adria- nople, and hence this color is olten called Adrimwple red. Even as late as the end of the last century the manufacture of Turkey-red yarn seems to have been extensively cariied on at Ambelakia and other places in the neighborhood of Larissa. An interesting account of the manufactuics and trade of this then flourishing district, by Felix, will Vje found in the An- iialex de Cfiimie, t. xxi. 1799. About the middle of the last century the art of Turkey-red dye- ing was introduced into France by means of dyers brought over from Greece. The French were also the first to dye pieces with this color, the art having previously been applied merely to the dyeing of yarn. The first establishments for dyeing this color in (ireat Britain were founded and conducted by Frenchmen. At the present day Turkey-red dyeing is carried on in various parts of France and Switzerland, at Elberfeld in Germany, in Lancashire, and at Glasgow. Turkey-red dyeing is essentially distinguished from other dyeing processes by the appli- cation previous to dyeing of a peculiar preparation consisting of fatty matter combined with other materials. Without the use of oil or some fatty matter it would be impossible to pro- duce this color, of which indeed it seems to form an essential constituent. If the color of a piece of Turkey-red cloth be examined, it will lie found to consist of red coloring matter and fat acid, combined with alumina and a little lime. The coloring n:atter thus obtained is so little contaminated with impurities as to appear on evaporating its alcoholic solution in yellowish-red crystalline needles. What part the fat acid plays, whether it merely serves to give to the compound of coloring matter and alumina the power of resisting the action of the powerful agents used after the operation of dyeing, or whether it also modifies and imparts additional lustre to the color itself, is quite unknown. The formation of this triple compoiind of coloring matter, fiit acid, and alumina, seems at all events to be the final result which is attained. Nevertheless, this apparently simple result can only be anived at by means of a long and complicated piocess, each step of which seems to be essential for its final success. The details of the process vary considerably both in theii- nature and number, in different countries and different dyeing establishments. They may however be described in general terms as follows : — The goods, after being passed through a soap 1 ath or weak alkaline lye, are oiled. For this purpose a mere impregnation with oil would not be sufficient. The oil must be mixed with a solution of carbonate of potash or soda, to which there is often added a quantity of sheep or cow dung, the ingredients being well mingled, so as to foim a n.ilky liquid or emulsion. Olive or Gallipoli oil is the kind generally used, and an impure, mucilaginous oil is preferred to one of a finer quality. Drying oils are not adapted for th.e i)urpc*e. In this li(|uid the goods are steeped for a short time, so as to become thoroughly impregnated with it. In the case of pieces the liquid is generally applied by means of a padding machine. After being taken out of this lifpiid the goods are often left to lie for some days in heaps, and if the weather is fine, they are then exposed on the grass to the action of the air ; other- wise, they must be hung up in a hot stove. Tliis process of steeping and exposing to the air is repented a number of^ times, until the fabric is thorougly impregnated with fatty mat- ter. Duiing tliis part of the process there can be no doubt that the oil undergoes a partial decomposition and oxidation, so as to become capable of uniting, on the one hand, with the vegetable fibre, and, on the other hand, with the coloring matter, with which it is subsequently brought into contact. The dung, by inducing a state of fermentation among the ingredients, probably promotes the decomposition of the oil into f^itty acid and glycerine, and the alkali serves to convey the fattv acid into every part of the fabric, and to assist m its oxidation on exposure to the air. The process of oxidation wliich takes place is sometimes so active as to TURKEY RED. 1063 produce spontaneous combustion of the goods in the stove. It might be supposed that by previously saponifying the oil, impregnating the goods with the soap, and, after suflicient exposure, decomposing the latter by means of an acid, the same object might be more easily attained than by the long process usually employed. This i.-^, however, not the case, which proves that we are still ignorant of the e.\act chemical nature of the change which takes place during the oiling process. The supposition formerly entertained, that the eflect of the oiling consi-sted in a so-called aniniallzation of the vegetable fibre, is quite untenable. In some establishments, the goods, after being oiled and stoved, are passed through a bath of very dilute nitric acid, and then exposed to the air belbre being oiled again, the process being repeated after every oiling. The nitric acid is supposed to contriljute to the oxidation of the oil. Several years ago a patent was taken out by .Messrs. Mercer and Greenwood for preparing the oil, previous to its being applied to the cotton, by treating it with sulphuric acid, and then with chloride of soda, but tiieir invention, though apparently of some import- ance, has not generally been adopted by Turkey-red dyers. After being oiled, the goods are steeped for some hours in a weak tepid solution of car- bonate of potash or soda. This operation, which is called by the French dcgraissage, serves to remove the excess of fatty acid, or that portion which has not thoroughly combined with the vegetable fibre. The liquid thus obtained is carefully preserved for the purpose of being mixed with the liquid used for the oiling of fresh goods, the quality of which it serves to improve. To this operation succeeds that of galling and mordanting. The goods, after being washed, are passed through a warm solution of tannin, prepared by extracting galls or sumac with boiling water and straining, after which they are impregnated with a solution of alum, to which sometimes a little chalk or carbonate of potash is added, or with a solution of ace- tate of alumina, prepared by double decomposition from alum and acetate of lead. Some- times the alum is dissolved in the decoction of galls, and thus the two operations are com- bined into one. The goods, after being dried in the stove, passed through hot water con- taining chalk, and rinsed, are now ready to be dyed. It has been asserted that the galling is not an essential part of the process, that it merely serves to fix the alumina of the mor- d.mt, and may l)e dispensed with when acetate of alumina is used instead of alum. It is certainly dilHcult to conceive how it can permanently affect the appearance of the color, since the tannin of the galls is undoubtedly removed from the fibre during the subsequent stages of the process. The dyeing is performed in the usual manner. The materials employed arc madder, chalk, sumac, and blood, in various relative proportions. The heat of the dye bath is grad- ually raised to the boiling point, and the boiling is continued for some time. The part played by the chalk in dyeing with madder has been explained above. It was formerly supposed that the red coloring matter of the blood contributed in producing the desired ef- fect in Turkey-red dveing; but to the modern cliemist this supposition does not appear probable. Nevertheless, it is certain that the addition of Ijlood is of .some benefit, though it is uncertain in what the precise effect consists. Glue is occasionally employed in the place of blood. Sometimes a second mordanting with galls and alum, and a second dyeing, is allowed to succeed the first mordanting and dyeing. After being dyed the goods appear of a dull brownish-red color, and they must therefore be subjected to tlie brightening process, in order to make them assume the bi-ight red tint required. For this purpose they are first treated with a boiling solution of soap and car- bonate of potash or carbonate of soda, and then with a mixture of soap and muriate of tin crystals. This operation is usually performed in a close vessel under pressure. The alka- lies remove the brown coloring matters and the excess of fat aciil contained in the color, and the tin salt probalily acts l)y extracting a portion of the alumina of the mordant, and substituting in its [ilace a ()uantity of oxide of tin, which has the ell'ect of giving the color a more fiery tint. The last finish is given to the color by treating the goods with bran or witii cliloride of soda. The chief objects which the Turkey-red dyer seeks to attain are, 1st, to obtain the de- sired eilect with the least possible expenditure of time and niateiial; 2d, to i)roduce a perfect uniformity of tint in the same series of dyeings; and, 3d, to impart to his goods a color which, though perfectly duraljle, shall be fixed as much as possible on tlie surface of the fal)ric. The last point is one of imjiortance in the case of calicoes dyed of this color, since this kind of goods is much employed for the ])n)dnction of a i)eciili.ir style of prints, in which poitions of tlie color are discharged, in order eitiier to rein.iin white or to l>c cov- ereil with other c;)lors. And if the red dye is too firmly fixed, or too (KHi)ly seated, it lie- comcs more dillicult to discharge it. In this respect the art has in modern times attained to such a degree of perfection, that the interior of each tliread of Turkey-red cotton will be found on examination to be perfectly white. This is particularly the ca.se with the Turkey reds from the establishment of .Mr. Steincr of Accrington, Lancashire, whose jiroductioiis in this branch of the art of dyeing are also unrivalled for the brilliancy and purity of their color. See Madder and Calico Pui.nti.ng. — E. S. 1064 UREA. u UREA. This is one of the principal constituents of urine, beins; always present in it, but in variable quantities: the average quantity in healthy urine is about 14 or 15 parts in 1,000 of urine, but of course this varies from several circumstances, as in disease, drinking a large quantity of liquid, kc. The urine passed the first in the morning gives a fair esti- mate of the quantity of urea yielded by the urine of an individual. It seems to be the prin- cipal form in which the waste nitrogenous compounds of the body are eliminated from the system. It is very prone to decomposition when in contact with albumen, mucus, or any fermentable matter ; and this is the cause of urine, which, when first passed, is generally slightly acid, becoming allvaline, and a precipitate being formed ; the change being much more rapid in hot than in cold weather, the mucus, &c., beginning to ferment sooner. The urea is decomposed into carbonate of ammonia, water being at the same time assimilated. Cn^NW + 4H0 = 2(NII^C0') Urea. Water. Carbonate of ammonia. The carbonate of ammonia neutralizes the acid which keeps the phosphates in solution, and hence the precipitate. In some diseases the quantity of urea in the urine amounts to 30 parts, and even more, in the 1,000 parts of urine. It is interesting as being the first organic base which was made artificially. It was found that cyanate of ammonia, which has exactly the same ultimate composition as urea, when dissolved in water and boiled for some time, became completely changed, neither cyanic acid nor ammonia being detected by the ordinary test in the solution, and that it had iu fact been converted by a molecular change into urea. NH\c=xo= = c=irx-o' Cyanate of ammonia. Urea. Its presence in the urine is detected thus : evaporate a portion of the urine over a water batli to about one fourth of its bulk, and when cold add half its volume of pure nitric acid, when after a little time abundant crystals of nitrate of urea will be formed. The quantity of urea in any sample of urine may easily be estimated by a process in- vented by Liebig. It consists in treating the urine with a standard solution of pernitrate of mercury. A copious white precipitate is formed, with liberation of nitric acid. As this acid prevents the further action of the nitrate, the urine is previously treated with a solution of two vols, of saturated baryta water, and one vol. of saturated solution of nitrate of baryta, which precipitates the phosphates, and the excess of baryta neutralizes the nitric acid as soon as it is liberated. The addition of the nitrate of mercury is continued until the last portion added causes a yellow binoxide of mercury instead of a white precipitate. The quantity of urea present in a given sample of urine may thus be readily deduced from the quantity of the nitrate required to precipitate it completely, the solution of nitrate of mercury being so arranged that every 100 grains of it shall be equal to one grain of urea. It is also to be noticed that no precipitate is formed in the presence of common salt ; that therefore has to be also removed by addition of nitrate of silver before using the nitrate of mercury. By an ingenious application of this fact, the quantity of common salt in any sample of urine may also be determined by the same solution of nitrate of mercurj'. Urea when in solution acts as an alkali on test paper; it unites with acids forming salts, the ni- trate and oxalate being the least soluble of them. Although urea is so easily decomposed, a pure solution of it may be kept a considerable time unchanged. — H. K. B. V VACUUM PAN. For a description of it, see Sugar. VALUE. Two methods have been adopted for ascertaining the value of our exports; one by means of the official value, the other according to the declared value. In Lowe's Present State of Eiiyland, (1822,) there is a very succinct and clear account of these meth- ods, which is here extracted : — " The official value of goods means a computation of value formed with reference, not to the prices of the current year, but to a standard, fixed so long ago as 1696, the time when the office of Inspector General of the imports and exports was established, and a Custom- house ledger opened to record the weight, dimensions, and value of the merchandise that passed through the hands of the officers. One uniform rule is followed, year by year, in the valuation, some goods being estimated by weight, others by the dimensions, the whole without reference to the market price. [Worsted stuffs are valued at £1 lis. 8c?. the piece, accordinir to MacGregor's Commercial Statistics.] This course has the advantage of exhib- iting. «i''i s'lii'f accuracy, every increase or decrease in the quantity of our exports. VEGETABLE EXTEACT. 1065 "Xext as to the value of these exports in the market: — In 1798 there was imposed a duty of 2 per cent, on our exports, the value of which was taken, not by the official stand- ard, but by the declaration of the exporting merchants. Such a declaration may be as- sumed as a representation of, or at least an approximation to, the market price of merchan- dise, there being on the one hand no reason to apprehend that merchants would pay a per- centage on an amount beyond the market value, while on the other the liability to seizure alForded a security against undue valuation." VEGETABLE EXTRACT. In offering any thing new, more especially as connected with an art so long practised as that of brewing malt liquors, Mr. Hodge, whose patent we are about to describe, is fully aware that changes in old established methods are never re- ceived readily. It is, however, evident that there are certain points to be attained in the production of malt liijuors, which, if carried out on scientific principles, would be a great boon to the profession. The present practice of first making an extract of malt, and then adding the hop-leaves to the wort in the copper, for the purpose of getting out their extractive matter (in a liquid already nearly to the point of saturation) is not in accordance with scientific principles. It is a well-known fact that, without long boiling, the resin, lupuline, and tannic acid of the hops are not readily disengaged from the leaf; hence we find ail brewers say that they like a good, lonr/, sharp boil to make the beer keep well. The two most antiputrescent ingredients are the lupuline and tannic acid ; but while the long boiling is going on to get these two ingredients liberated, the volatile oil, or that which gives the softening principle, as well as the aroma, to t.he ales, passes off into the atmosphere and is lost, so that the beer or ale has a nasty, rough, acrid taste, somewhat like gentian root. The great question is ? what are the constituents of wort liquor when drawn from the mash tun, what do we want to retain, and what to get rid of: The worts are composed of water, saccharine matter, starch in small quantity, albumen, and gluten. The saccharine matter is the only thing we want to retain, save its proper proportion of water. The other ingredients are nitrogenous, and liable to produce putrid fermentation. Boiling of the worts is intended to coagulate the nitrogenous matter ; two minutes will do this at 200° Fahr. What must now be effected is to bring these particles of coagulated matter into contact witli the tanning, resinous, and lupuline properties of hop, rendering them insoluble ; which chemical change prevents, in a measure, further decomposition for a time, until they are nearly all got rid of by fermentation or after precipitation. There cannot be a doubt that boiling worts to a certain extent is necessary, but long boiling is decidedly injurious, as there must be a decomposition of the saccharine matter going on, as well as a reglutinization of the albumen and other compounds, unless these particles are immediately brought into contact with those properties of the hop to arrest it. All these difficulties can be prevented by first making an extract of hop in a close digester, as is represented in the enclosed drawing, /f^. 674. The most volatile properties can either be distilled over, or drawn off from the top, and added to the worts after they are cooled, and before fermentation. The keeping princii)le of the hop will then be drawn off in a strong decoction and added to the worts after they are allowed to boil a few minutes, when the particles of nitrogenous matter will be immediately changed, retaining the aroma and other delicate properties of the hop. Hence the advantage of the separate extract of hop, in vessels where the temperature can be regulated to the greatest nicety, and where the air cannot come into contact to change the color of the liquid or lose the aroma. Another advantage in this process is, not allowing the hop leaf to go into the wort, thereby saving one in every 30 barrels brewed, or 3 per cent, on all malt extract, which to some brewers would amount to £20,000 per annum. Fir/s. 674, 1 ami 2, (.v and a,) are two digesters, which are supplied with water to the interior at 212' Fahr. This is admitted by the water-pi[)e passing through tiie hollow journal, and thence down the side pipe in the interior of the vessel below the perforated platform b'. The hops are placed between these platforms b b and b'. Steam is let on from the steam-pipe passing through the hollow journal, and into the steam-jacket c, c, c, which keep up the temperature of the mass at or above 212° Fahr., as may be deemed necessary ; at the same time no steam is allowed to escape, hence the whole of the aromatic properties of the hop are preserved. This is done in two ways ; first, by drawing off the top of the extract through the cock e, (this is added to the beer after it is cool;) or, the hop oil is distilled over by means of the hood f, and condenser «, and is run off through the cock ii fiij. 675. The cover D is then drawn up by the cliain and counter-weight. The extract is then drawn off through the bottom cock j, and is added to the boil. The perforated plat- form is removed, and the vessel, which swings on the trunnions, is turned upside down and the spent hops drop into a press. See Brewi.vg. Cooliriff. — The quicker worts are cooled down to the fermenting temperature after being boiled, the better. Tlie less it is expo.sod to the action of the atmosphere the less liable it is to absorb oxygen, preventing acetous fermentation. 1066 VEGETABLE EXTRACT. Rapid cooling to all brewers is of vital importance, for if wort be permitted to come into contact with the air during the time its caloric is given off, aciditv must set in, espe- cially in summer time. The best method to cool worts is that which is shown and described in the drawing annexed, _^^. 675. VENTILATION OF MINES. 1067 The worts are passed through copper tubes, thoroughly tinned. Instead of passing a current of water round these tubes, a dew jei of water is sprinkled all over the outer sur- f;ice, at the same time a current of cold air is brought into contact with the moist surface of the tube, so that as fast as the molecules of caloric are transmitted to the water through the metal tubes, they are blown away, giving place to others. By this process heat from liquids can be abstracted more rapidly than by any other. In fact, worts can be brought down to freezing temperature, although tho water used may be 80' to lUO" Fahr. Another great advantage is, that the quantity of water used is about one-half. These tubes can be cleaned with a brush with perfect ease. VEXTILATION OF MIXES. In our subterranean operations, especially where quan- tities of carbonic acid are constantly being produced by respiration and combustion, and where, especially in our coal mines, the workmen are constantly exposed to the efflux of ex- plosive gas — light carburetted hydrogen — it becomes necessary to adopt the means of remov- ing, as rapidly as possible, the air by which the miner is surrounded. See Strute's Mine Ventilator. Description of the Ventilating Fan at the Abercarn Collieries. — The mode of ventilation that is still generally used in the collieries of this country is the old furnace ventilation, where the required current of air through the mine is maintained by the rarefaction of the column of air in the ascending shaft, by means of a large fire kept constantly burning at the bottom of the shaft. In Belgium and France, on the contrary, this plan is almost super- seded by the use of machinery to maintain the current of air ; as the furnace ventilation, although possessing the important advantage of great simplicity and freedom from liability to derangement from dis- turbing causes, has some serious objections and deficiencies, and in some cases becomes so imper- fect a provision for ven- tilation as to render a better system highly de- sirable and even neces- sary. Mr. E. Rogers, having occasion to ventilate the workings in some ex- tensive and very fiery coal seams recently won at Abercarn in South Wales, under circum- stances where the fur- nace ventilation could not be applied, after carefully collecting every accessible information as to the ventilating machines used in Great Britain and on the Con- tinent, came to the con- clusion tliat a plan of machine proposed for the purpose some years since by Mr. James Nasmyth would be the most suita- ble and effective. After consultation with Mr. Nasmyth, it was resolved to test the principle and plan by actual practice ; and the ventilating fan described was ma(le at Patricroft by Mr. Nas- myth, and is erected at the Abercarn Collieries. The general arrange- ments of the top of the shaft and the ventilating fan are shown m figx. CYG and 677. Fig. 678 is a side elevation of the fan and engine, to a larger scale ; anil jf^r. 677 a vertical section of the fan. 1068 VENTILATION OF MINES. The fan a A,f(j. 677, is 13i^ feet diameter, with 8 vanes, each 3 feet 6 inches wide and 3 feet long. It is tixcd on a horizontal shaft, n, 8 feet 7 inches in length from centre to cen- tre of the boarhigs, which are 9 inches long by 4^ inches diameter. The vanes are of thin plate iron, and carried bj' forked wrought-iron arms secured to a centre disc, c, fixed upon the shaft B. The fan works within a casing d d, consisting of two fixed sides of thin wrought plate, en- tirely open round the circumfer- ence and connected together by stay rods ; the sides are 3 inches clear from the edges of the vanes, and have a circular opening 6 feet diameter in the centre of each, from which rectangular wrought- iron trunks, E K, are carried down for the entrance of the air ; the bearings for the fan ,«haft b being fixed in the outer sides of these trunks, A\hich are strengthened for the purpose by vertical cast- iron standards f bolted to them, and resting upon the bottom foundation stone g. The two air trunks e e join to- gether below the fan, as shown iu />(/. 67(5, and communicate with the pit ii by means of a hor- izontal tunnel, i, which enters the pit at 21 feet depth from the top. The fan is driven by a small direct-acting non-condensing en- gine, K, which is fixed upon the face of one of the vertical cast- iron standards f, and is connected to a crank on the end of the fan shaft B. The steam cylinder is 12 inches diameter and 12 inches stroke, and is woiked by steam from the boilers of the winding engine of the pit, at a pressure of about 13 lbs. per square inch. The eccentric l for the slide valve is placed just inside the air trunk E, and works the valve through a short weigh sliaft, m, with a lever on the outside. The pit II, ff/. C76, is of an oval form, 10 feet by 18 feet, and divided near the centre by a tim- ber brattice, N, the one side form- ing the upcast shaft and the other the downcast. Both of these are used for winding, and the cages o, in which the irucks, &c., arc brought up, work between guides fixed to the timbering of the pit. The pumps p are placed in the downcast shaft. In order to allow of the upcast shaft being used for winding, the top is closed by an air valve, R, which is formed by simply boarding up the under side of the oidinavy guard upon the mouth of the sliaft, leaving only the hole in the centre through which the chain woiks. This air valve R is carried up by the cage o, on arriving at the top of the shalt, as in Jjr/. 676, and then drops down again flat u[)on the opening, when the cage is again lowered. During the time that thc'valve is lifted, its place is occupied by the close bottom of Ihe cage o, which nearly fills the rectangular opening left at the top of the shaft. By this sim- ])le means it is found practically that a complete provision is made for keeping the top of the upcast shaft closc(l, and maintaining a uniform current of air up the shaft ; for the leakage of air dov.-nwards through tlie top whilst the cage is iu the act of opening or closing the air valve, and through the small area that always remains open, is found to be f|uito im- material, and the surfjlus ventilating power of the fan is amply sufficient to provide against it. WASHING COAL. 10G9 In the original construction a more perfect air valve was supposed to be requisite, antl was provided by the inclined flaps s s, which are fixed just above the horizontal tunnel i. These are fitted closely together, leaving only a small opening in the centre for the chain to pass through, and were intended to be opened by the ascending cage coming in contact with them, closing again directly by means of balance weights before the air valve R at the top of the shaft was opened, so as to preserve a thorough closing of the top of the shaft. The flaps were to be opened again by a lever from the top to allow the cage to de- scend. Uowever, it was found on trial that the valve r at the top was amply sufficient ; and consequently, although the other valves were also provided, they have never been put into use. The total depth of the pit is neariy 300 yards, and at a depth of 120 yards a split of air is taken off, and coursed through workings from which coal and fire-clay are got ; the larger portion of the air descends to the bottom of the pit, and is there split into many courses, to work two separate seams of coal and a vein of iron stone. The total length of road laid with plates or rails in the workings is about 7 miles, and the working faces amount to nearly double that distance. The longest distance that is traversed by any single course or split of air, in passing from the downcast to the upcast shaft, is nearly 2 miles. The quan- tity of materials raised from the pit is about 500 tons daily. The following Table gives the results of a series of experiments made with this ventilat- ing fan by Mr. K. S. Roper, showing that the quantity of air delivered at the velocities of 60 and 80 revolutions of the fan per minute is 45,000 and 66,000 cubic feet per minute, with a velocity of current of 782 and 1,037 lineal feet per minute respectively, or about 9 and 12 miles per hour ; and the degree of vacuum or exhaustion in the upcast shal't is "5 and '9 inch of water respectively. Synopsis of Experiments on Fan Ventilation. Heiglit of 'lemperatura i^ ^ '■< . a "3 Biirometer. by Fahrenheit's Thermomoter. ° 3 go '•< •■ Sj u" . •2 £ Is. ^1 Water gni Velocity of in feet p minute ® 3 1 0. < = 1/1 ^1 ^1 "3 « m a i1 feet c. feet Mean of twelve experi- ins. 1 ins. deg3. degs. degs. dega. revs. ins. p. min. p. min. lbs. lbs. ments. Natural Ven- tilation - - . 29-61 30-60 41-10 51-73 55-56 4S-00 -15 446-0 24,825 Mean of four experi- 1 nifents. Fan VentiLation 29-85 30-85 8S-10 50-10 53-93 47-30 60 -50 781-8 45,187 13-0 17-4 Mean of five experi- ments, Fan Ventilation 29-65 30-61 41-40 50-70 55-10 48-70 80 •90 1037-0 50,555 1-93 23-2 The speed at which the ventilating fan is usually worked is about GO revolutions per minute, giving a velocity at the circumference of the fan of 2,545 feet per minute; 45,000 cubic feet of air per minute are then drawn through the mine, nearly one-third of which ventilates the upper workings, and the rest passes through the lower workings. In these experiments the mode adopted for ascertaining the velocity of the air currents was by calculation from the difference of pressure, as observed by means of a carefully con- structed vacuum gauge, the result being cheeked by the anemometer and by the time of passage of the smoke of powder fired at fixed distances by means of wires from a voltaic battery at the top of the shaft. For further information upon this subject see articles, Mines, Ventilation of; Pit- coal ; and Ventilation, vol. ii. VERJUICE. {Verjux^Yw; Arp-cst, Germ.) A har.sh kind of vinegar, containing much malic acid, made from the expressed juice of the wild crab apple. VINE BLACK. A black procured by charring the tendrils of the vine and levigatuig them. w WASHING COAL. M. Berard is the inventor of a very successful apparatus for puri- fying small coal. He exhibited his arrangement at the Great Exhibition of 1851, receiving the council medal. Tlie decoration of the Legion of Honor and a gold medal was also awarded to him at the Taris Exhibition in 1855. This apparatus, to be presently described, elfects, witliout any manual labor, the following operations: — 1st. The sorting of the coal by throwing out tlie larger pieces. 2d. Breaking the coal, which is in pieces too large to be subjected to the operation of washing. 3d. Continuous and perfect purification of the coal. 4th. Loading the purified coal into wagons. 5th. Loading the refuse (pyrites or schist) into Viagons for removal. 1070 WASHING COAL. The power required for the apparatus is that of from four to five horses, and the ma- chine can operate upon from 80 to 100 tons of coal in about twelve hours, if fitted up near the colliery. The expense of the operation of purifying is stated to consist solely in the wages of the workmen charged to conduct the labor of the machine. The following description of the/y.5. GfO and 680, will render the arrangements of M. Bcrard's machine readily intelligible. ^ ""'^^^^^^ The coal is cariied from the mine on a staging, for example, and the tram-wagon b is unloaded into a hopper, c, either by opening the bottom or by tilting it (as in the position represented by the dotted lines b) by means of a lever. It falls afterward cither on to a ta!»le or a movable grating, d, formed of frames, or of a series of stages, of sloping perfor- ated plates, which immediately sorts it into as many sizes as there are perforated plates. fiSO This grating is suspended out of a perpendicular by four chains or iron rods, c c, fixed to the framework of the staging A. It is moved by means of a cam motion (an arrange- ment of a cam and tongue mentonnct) c', and falls back by its own weight against the stops, which produce concussions or vibrations favorable to the clearing out of the holes and to the descent of the materials. The motion communicated to the grating admits of a mucli less inclination being given to it than would be the case if it were fixed : the sorting is ef- fected quicker and more perfectly, besides which the diflerences of level which it is neces- sary to preserve are maintained. The larger pieces rejected by the first plate reach the picking table e, where a laborer picks out the largest stones and extraneous sub.^tances as fragments of castings, iron, &e. The fragments which have passed through the upper ])late, and are retained by that be- low, descend direct to the crushers f f', situated below. Lastly, the fine poitions of the coal which have passed through the second perforated plate fall on to a solid bottom, a', wl-.ence they arc thrown, delivered direct into the pit l)y means of a fixed shoot, c. The crushing cylinders f f' are made with a covering of cast-iron, mounted on an iron .'^haft. This covering can lie easily replaced when worn out. It has on its surface small grooves, which are usually placed longitudinally, parallel with the axis of the cylinder, in order to avoid the .^lipping of the substances operated on. But it is also necessary to crush fragments of slate which gain admission with the coal, and these consisting of thin, flattened lanjina?, it would be necessary to bring the cru.sher closer than would be required to reduce the coal which is of a more cubical form to the jiropcr size. In order to obviate this difficulty another series of gioovcs are formed on the surfaces of the cruslier transversely to those already descriljed, the intersection of the two producing WASHING COAL. 1071 projections in the form of quadrangular pyramids, with slightly rounded tops. In coming between the projections of the crushers the fragments of slate, being unable to pass, are broken up without reducing the coal to a smaller size than is recjuired. When the coal has undergone a preliminary sii'ting, which has removed all the pieces exceedin'^ 6 or 7 centimetres in size, one pair of crushers is sulficient. In that case the grating may be dispensed with altogether by discharging the coal direct into the pit, and returning from the sifter to the washer the pieces of coal which have not been able to pass beyond the first perforated plate. ' The small coal resulting from the washer, or from the sifter, by means of the jigger, is di'livered into a common pit placed under the washers. The pit is shaped like an inverted quadrangular pyramid, the three laces of which are inclined to one another at an angle of 45 \ to facilitate ihe descent of the substance, and the fourth is usually vertical. It is on the latter that an opening is made, which is regulated by a flood-gate. An elevator, formed of an endless chain, with buckets, raises the coal from the bottom of the pit, places itself sufficiently high to allow of the final discharge, which may take place iato the wagon. The rate of ascent of the buckets and their capacities are calculated so as to raise 160 to 200 tons of coal in the working hours ; but this quantity may be diminished by means of the flood-gate in the pit. The coal discharged by the elevator falls on the sorter, which ought immediately to di- vide it, according to size, and distribute it to the ferry-boats. The classifier is formed of a kind of oblong rectangular chest, made of iron plates, in the inside of which are placed stages of perforated plates, the apertures in which decrease in a downward direction. Suflicient space is allowed between each plate for the motion of the materials. At the bottom of the perforated plates are disposed inclined planes for throv/ing on one side the product of the sifting, which escapes through a slope made on the side of the sifter. A bottom fixed to the classifier itself, and like it movable, receives the dust in the finest numbers, if the sifting has been effected in the dry way, or else this bot- tom is immovable and fixed to longerons which support the classifier, if the sifting takes place in water, as we are about to point out. The classifier is suspended by two or three pairs of articulated handles turning on axles fixed to longerons: by that means it enjoys an extreme freedom of motion in a longitudinal direction. A rapid reciprocating motion is communicated by a " biellc,^'' which receives the action of a bent axle firmly estal)lished on a foundation fixed on the principal wall of the chamber of the machine. The motion of rotation is communicated to the axle by the dis- position of an iron pinion d^anr//.e working into a. The bac is formed of a rectangular chest in cast-iron, l', one part of the bottom of which is inclined at 45^, the other lower parts remaining horizontal. Opposite one of the lesser sides of the rectangle is placed a cylinder, o, opening into the oblong chest at about half its height. The chest l' is prolonged under the cylinder, in or- der to increase the stability of the system and the capacity of the drain-well, (puisard.) A cast-iron box, u m', is firmly fixed in the interior of the bac, on flanges of cast-iron with vertical fiices. This box has a slight inclination from m toward m'. It is covered with a perforated plate, usually of copper, fastened to the frame by a number of iron pins or bolts easy of replacement. The size of the holes varies according to that of the matters brought into the bac. A cast-iron door, n, traverses, opening outward, is fixed at a slight height above the frame, serving as a kind of partition dividing the materials in the bac, and against it a flood- gate, n', by means of which the opening beneath the cast-iron door may be closed at pleasure. A counter flood-gate, n', is placed at the lower extremity of the frame ; in raising it a barrier is formed of varialjle height, by means of which the substances between the flood- gate and counter flood-gate may be arrested. A piston, c, receives from the machine a sufficiently rapid reciprocating motion. Every thing being tlius arranged, if the l>ac is su[)posod to l)e filled with water to the level of the front face at n', and that the substances to be washed fill the space in (he bae between tliis level and the perfoiatcd plate of the frame, the piston \^■orking upward and downward will press the water in the body of the cylinder, and will force it l)y its iiiconi- [)res.sibility to pass through the holes in tlie perforated plate; it will establish aliove this [ilate an ascending current, which, if of sulficient power, will raise the substances sul)m('rged. The resistance to the rise of each body will be in proportion to its specific gravity, and. to 1.5. CcZ. per ton. The ordinary washing processes sacrifice more than 20 per cent, in weight, of which more than one half is the best coal. In this machine the water does not pass out, but is used over and over again in a continuously circulating stream. The loss of coal does not exceed 2 per cent., and is generally under 1 per cent. 3d. The economy in the power required to work the machine. 1 -horse power will suf- fice to work a machine with pump and elevator capable of purifying 50 tons of coal per day. 4th. The saving in manual labor. 5th. The quantity of water required is comparatively insignificant. A small supply of water is required to replace that absorbed by the wetting of the shale and coal. 6th. The coal is delivered drier than by any other existing process. Vth. The largest machine stands in an area of 9 feet square, and motion can be given off any existing engine by a strap to a pulley making 40 revolutions per minute, at a height of about 12 feet al)ove the ground. The height given to the machine is for the purpose of passing trams underneath it to receive the purified coal and shale as they are delivered. The machine requires no foundation, and is easily removable. 8th. The great economy of the process in every point of view is important to — The coke trade. — Many coals when deprived of their impurities will coke which never coked before, and the quality of every description of coke may be greatly improved. In coals above the average in (juality, it has been found that the clinker may by water purifica- tion be reduced by four-fifths in quantity. The two principal sources of clinker — the wliit- ish scales of carbonate of lime and the iron pyrites — are removed. A coke more uniform in texture ami better in appearance is produced, and different descriptions of coal may be simultaneously mixed and purified by this macliine. A cost of 3(/. per ton on the coke will remove those impurities for which tlie consumer now pays at the .same rate as the coke it- self. An increase in the make and quality of the iron results from using purified coke in blast fnniaccs. Persons using steam. — The amount of ash and clinker from a coal, by no means re- presents tlie full amount of loss and waste occasioned by tlicm. The coal is imperfectly burnt, and the fire bars are injured. By removing the impurities, much of tlie laljor in at- tending boiler fires may be spared, and the steam kept up more regularly. In steamers^ and whenever the freight of coal is heavy, these advantages are peculiarly important. _ Gas companies. — Gas may be produced comparatively free from sulphur, as well as a purer and more valuable coke. By a small addition to tlie cost of the machine the coal may be dehvered in a dry state. Siniliis and workers in metal. — A coal purer than the large coal is produced. Better work and metal and cleaner heartlis are the results. Smiths are paying in several instances nearly double the former prices for coals which have been purified. In puddling and other furnaces tlie advantages of pure coal have been well ascertained. Patent fuel companies. — In all cases where freights are heavy and the manipulation of the fuel costly, purity in the raw material is cs.sential. CoUierii owners. — Coal and shale in lieu of being thrown into the gob can be brought out of the mine and separated for from Is. to 2s. per ton, including haulage, &c. Crop coal, old pillars, and creeps may be turned to account. Tlie spontaneous combustion in the wastes of some mines may be iv.-cveiitod l)y l)ringing out tlie whole of the small coal and [lyiites at a now rcmunorative price. New coal scams may be brought into the market, to the l)enefit both of tlie jirodncer and consumer. In working this machine tlie coal tram is tipped into tlie coal lioppcr ; it is tlience con- veyed by the elevator in a continuous stream into the machine, and tlie purified coal is delivered continuously into a tram, whilst the shale and pyrites are delivered in a continu- ous manner l>y the dredger, or Jacob's ladder. Tiie workman ha.s oidy to attend to the jilacing of tiiese wagons and regulating the aniount of opening of the valves, which allow the shale to descend into the shale box after it is separated. Vor,. III.— r.8 1074 WATER PRESSURE MACHINERY FOR MINES, The revolving hopper allows the coal to descend gradually into the separator, where a plow current of water is driven upwards thvough the mass of shale and coal, at a velocity of from 4 to 5 feet per minute, by tlie agitator or screw. Tliis water passes back again by the finely perforated plate, and with the fine silt suspended in it, is again driven upwards by the screw to undergo a repetition of tho process. The gentle agitation produced by this current separates the shale and pyrites from the coal in the separator, the two latter descend through the valves and are talcen up by the dredger, whilst the former is pushed upwards out of the water by the curved arm ; and as soon as tlio water has drainecl off, the coal falls on to tlie shoot, which conducts it to the tram. A brush following the arm helps to keep the holes in the perforated plate open. The valves remain constantly more or less open, according to the indications given by the dredger, and are regulated by the valve lever. The water required to rei)lace that absorbed by the dry coal and shale enters by the hopper and flows .slightly inwards through the shale valves as the shale is coming out. The objects said to be attained by the machine are: 1st, a more perfect separation of the impurities than by the jigging or huddling processes; 2d, a saving of from 5 to 15 per cent, of coal ; 3d, economy of power and manual labor ; 4th, saving of water and the de- livery of the coal in a drier state. Machines have been established in Scotland, Cumberland, Derbyshire, Gloucestershire, and Wales, to purify from 20 to 100 tons of coal per day, at a cost not exceeding 3c/. per ton, and with a loss not exceeding 2 per cent, of coal. WATER PRESSURE MACHINERY FOR MIXES. Con.siderable attention has been given to the construction of pressure engines by Mr. Darlington, who was actively engaged some years since in effecting the drainage of the Alport Mines, in Derbyshire. Sec fig. C82. The first engine erected by him had a cylinder 50 inclies diameter, and a stroke of 10 feet ; the piston-rod passed tiirough the bottom of the cylinder and formed a continuation with the pump-rod, whilst the valve and cataract gearing was worked by a rod connected with the top of the piston, which gave motion to a beam and plug-rod gearing. The column of water was 132 feet high, affording a pressure on the piston of about 58 pounds per square inch, or more than 50 tons on its area. The water was raised from a depth of 22 , fathoms, by means of a plunger 42 inches diameter, and in very wet seasons it discharged into the adit nearly 5,ii00 gallons of water per minute. Water was admitted only on the under side of the piston, and in order to avoid violent concussion in working ; two sets of valves were employed, the larger being cylindrieally shaped, 22 inches diameter; and the smaller 5 inches diameter. In making the upstroke of the engine the cylindrical valves admitted a full flow of water for about | of the stroke, and then commenced closing, but at this stage the small valve opened, through which passed sufficient water to terminate the stroke. In this way the flow of water in the column was gradually slackened, and finally brought to a state of rest without imparting impact to the machinery. The speed of the engine was 'regulated by sluice valves, one fixed between the engine and the pressure column, and the other upon the discharge-pipe. The cylindrical valves were made of brass with a thin feather-edged beat, and kept tight by a concentric l-ioss, projecting from the nozzle, upon which hemp packing was laid. This was pressed down by a projection in the under surface of the valve bonnet. The water thus acted on the exterior of the valves between the zone of packing and the seatings, and when opened pa.ssed through the latter. Besides this engine, others of a different construc- tion were designed and erected by Mr. Darlington, but the one to which he gave preference for simplicity, cheapness, and smoothness of action, is illustrated in the following woodcut. This engine has one main cylinder a, resting on strong cast-iron beareis b b, fixed across the shaft. The piston-rod c is a continuation of the pump-rod s, and works through the cylinder bottom d. In front of the cylinder a, is a smaller one, e, with differential diam- eters for the admission and emission of water, and right and left are sluice valves not shown for regulating the speed of the engine. Connected with the second cylinder is a small 3-inch auxiliary cylinder, f, provided with inlet and outlet regulating cocks. In starting this engine the sluice valves and regulating cocks are opened, the water then flow from the pressure column o, into the main cylinder a, through the nozzle cylinder e, and acts under the piston ir, until the upstroke is completed. The piston i hasa counter j)iston K, of larger diameter, and when relieved from pressure on its upper surface, the water acting between them forces it upwards, in which case the pressure is cut off from the ruain piston, and the water contained in the cylinder a is free to escape under the piston i, through the holes l. With the emission of watc^r from the main cylinder through m, the downstroke is effected. The downward displacement of the pistons i and k is performed by the auxiliary cylinder f, and pistons n, o ; the pressure column is continually acting be- tween these pistons, and by their alternate displacement by the fall-bob p, and canti-arbor q. The water is either admitted or prevented from operating on the upper surface of tlic piston K. The water from the top of piston k escapes through the aperture R. The motion of the canti-arbor q is effected by tappets fixed on the pump-rod s. One of these engines was recently in operation at the Miucra Mines, in North Wales. WATER PRESSURE MAOHIKERY FOR MINES. 1075 The cvlinder was 35 inches diameter ; stroke 10 feet, pressure-column 227 feet high. Its average speed was 80 feet and maximum speed 140 feet per minute. The pressure of 6S2 M *? 1076 WATER PRESSURE MACHINERY FOR MINES. water under the piston was 98 pounds per square inch, giving a total weight on its area of about 40 tons. This macliine required no personal attendance, the motion being certain and continuous, as long as the working parts remained in order ; consequently the cost of maintaining it was of the most trifling character. In 1803, Trevithick erected an engine at the Alport Mines which worked continuously for a period of forty-seven years, or until 1850, when the mines ceased working. The water from tlie i)ressure-column acted on alternate sides of the main piston, by means of two pis- ton valves, displaced by a heavy tumbling beam, and tilted by a projection from the pump- rod. The construction and action of this machine will be best understood by the accom- panying illustration, jig. 083. A, main cylinder ; b and c, valve pis- tons ; D, chain wheel, upon the axis of which is fixed a lever not shown, in con- nection with a tumbling beam ; e, aper- ture through which water enters from pressure-column ; f, pipe in communica- tion with main cylinder a, and g, pipe for discharging the water admitted both above and under the main piston h. The posi- tion of the valve pistons in the woodcut shows that the pressure-column is sup- posed to be flowing through the holes i, upon the piston h, producing a down stroke, and that the water which has been introduced under this piston in order to make the up-stroke is leaving through the pipe f, holes k, and outlet jupe g. By referring to HYiiUArLic Cranks, the principles adopted by Sir Wm. Arm- strong will be understood. It is not necessary to repeat that part of the subject in this place, but it re- mains to notice the applications made of the pressure derived from natural falls. When the moving pcn'er consists of a natural column of water, the pressure rarely exceeds 250 or SOO feet ; and in such cases he has employed to produce rotary motion, in preference to the origi- nal scheme of a rotary engine, a pair of cylinders and pistons, with slide valves resembling in some degree those of a high-pressure engine, but having relief valves to prevent shock at the return of the stroke, as shown in f(j. 330, already described. Where the engine is single- acting, with plungers instead of pistons, as in the water-pressure engines already described, the relief valves are greatly simplified, and in fact are reduced to a single clack in connection with each cylinder, opening against the pressure, which is the same as the relief valve in the valve chest of the hydraulic crane. The water- pressure engines erected at Mr. Beaumont's lead mines, at Allenheads in Northumberland, present examples of such engines applied to natural falls. They were there introduced under the advice of Mr. Sopwith, and are now used for the various purposes of crushing ore, raising materials from the mines, pumping water, giving motion to machinery for washing and sep- arating ore, and driving a saw-mill and the machinery of a workshop. In all these cases nature, assisted by art, has provided the power. Small streams of water, which flowed down the steep slopes of the adjoining hills, have been collected into reservoirs at eleva- tions of about 200 feet, and pipes have been laid from these to the engines. Another application of hydraulic machinery at the same mines is now being made in situations where falls of sufficient altitude for working such engines cannot be obtained, which from its novelty deserves special notice. For the purpose of draining an extensive mining district and searching for new veins, a drift or level nearly six miles in length is now being executed. This drift runs beneath the valley of the Allen nearly in the line of that ' river, and upon its course three mining establishments are being formed. At each of these WATER, SEA. 107T power is required for the various purposes above mentioned, and it was desired to obtain this power without resorting to steam engines. The river Allen was the only resource, but its descent was not sufficiently rapid to permit of its being advantageously applied to water- pressure engines. On the other hand, it abounded with falls suitable for overshot wheels, but these could not be applied to the purposes required without provision for conveying the power to many separate places. Under these circumstances it was determined to employ the stream through the medium of overshot wheels in forcing water into accumulators, and thus generating a power capable of being transmitted by pipes to the numerous points where its agency was required. In this arrangement intensity of pressure takes the place of ujug- nitude of volume, and tiie power derived from the stream assumes a ibrm susceptible if unlimited distribution and division, and capable of being utilized by small and compact machines. A somewhat similar plan is also adopted at Portland Harbor, in connection with the coaHng establishment there forming for the use of the navy. The object in that case is to provide power for working liydraulic cranes and hauling machines, and more particularly for giving motion to machinery arranged by Mr. Coode, the present engineer of the work, for putting coal into war steamers. A reservoir on the adjoining height alfords an available head of upwards of 300 feet ; but in order to diminisli the size of the pipes, cylinders, and valves connected with the hydraulic machinery, and also with a view of obtaining greater rapidity of action, a hydraulic pumping engine and accumulator are interposed, for the pur- pose of intensifying tiie pressure and diminishing the volume of water acting as the medium of transmission. WATER, SEA — rendered fresh. {Commimicated bi/ Dr. Normandif.) The analyses of sea water which have been made at various times, and the results of which will be found elsewhere, prove that that liquid contains from 3i- to 4 per cent, of saline substances, two- thirds at least of which are common salt, and also a certain quantity of organic matters, all of which substances impart to it its well-known taste and odor, and render it unfit for drink- ing or other domestic purposes. To render sea water drinkable, and thus avoid the accidents resulting from an insuffi- cient supply, or from an absolute want of fresh v/ater, in sea voyages, is a problem which may be said to have engaged the attention of men from the very moment they ventured to lose sight of the friendly shore and became navigators ; gradually, as the enlargement of commercial operations extended the length of sea voyages, the difficulty of preserving in a pure state the fresh water taken in store, the necessity of putting up at stations for procur- ing a fresh supply of it when it is exhausted, the great gain to bo realized by being enabled to devote to the stowage of cargo the valuable space occupied by water-tanks and water- casks, have induced many people at various times, and for many years past, to contrive appa- ratus by means of which sea water would be rendered fit to drink, or by means of which good fresh water could be obtained therefrom. Fresh water can be obtained from sea water in two ways ; the one by distillation, the other by passing it through a layer or column of sand, or of earth, of sufficient thickness or length. Tn effect, if sea water be poured at a, in a pipe 15 feet high, and full of clean dry sand, the water, which will at first flow at b, will be found pretty fresh and drinkable, but as the operation is continued, the water which flows at B soon becomes brackish ; the brackishness gradually augmenting, until, in a very short time, the water which flows at b is actually more salted than that poured at a ; because the latter dissolves the salt which had been first retained by the sand, which must then be re- newed, or washed with fresh water, a process evidently useless for the purpose in question. This phenomenon, according to Berzelius, is due to the interstices between the grains of sand acting as capillary tubes; and as, at the beginning of the operation, the effect depends more on the. attraction than on the pressure of the liquid poured in one of the branches of the tube, the salt is partly separated from the ■water which held it in solution, the latter lodging itself into the inter- stices of the sand, and filling them ; if, when the mass of the sand is completely wetted, a greater quantity of sea water is poured upon it, the weight of the said sea water first displaces and expels the fresh water ; but as soon as the interstices of the sand have thus been forci- bly filled up witli sea water, the water flowmg at b becomes more and more salted; wherefore this filtration cannot yield more fresh water than can be contained in the interstices of a column of sand of a cer- tain length and proportionate to the saltness of the sea water. Howbeit, the removal of the salt from sea water, so as to obtain fresh water therefrom, is, practically speaking, an impossibility, except by evaporation. At first sight one would think that it is sufficient to submit sea water to distillation to 684 1U78 WATER, SEA. convert it into fresh water, and that the solution of the problem is altogether dependent upon a still constructed so as to produce, by evaporation, a great quantity of distilled water, with a consumption of fuel sufficiently small to become practicable. Distillation at a cheap rate is doubtless an important item, and fuel being a cumbrous and expensive article on board ship, it is superabundantly evident that, supposing all the apparatus which have hitherto been contrived for the purpose to answer equally well, that one would clearly merit the preference which would produce most at least cost ; but there are, besides, other desiderata of a no less primary importance, and it is from having neglect- ed, ignored, or been unable to realize them, tliat all the apparatus for obtaining fresh water from sea water, which have been from time to time brought before the public, have hitherto, without exception, proved total failures, or, after trial, have been quite discarded, or fulfil the object in view in a way so imperfect or precarious, that, practically speaking, the man- ufacture of fresh water at sea, or from sea water, may be said to have been, until quite lately, an unaccomplished feat. In order to understand the nature of the difficulties which stood in the way of success, a few words of explanation become necessary. When ordinary water, whether fresh or salt, is submitted to distillation, the condensed steam, instead of being, as might be supposed, pure, tasteless, and odorless, yields on the contrary a liquid free from salt, it is true, but of an intolerably nauseous and empyreumatic taste and odor, which it retains for many weeks; it is, moreover, insipid, flat, and vapid, owing to its want of oxygen and carbonic acid, which water in its natural state possesses, and of which it has been deprived by the process of distillation. In the absence of ordinary fresh water, this distilled water, however disagreeable and objectionable it may be, is of course of use so far as it is fresh, but the crews invariably refuse it as long as they can ob- tain a supply from natural sources, even though this may be of so bad a quality as to endan- ger their health or their lives, as evidenced by the report of The Times' Own Correspondent in reference to the water supplied to the crews of our ships in the Baltic during the Crime- an war. With a view to remedy the defects just alluded to, various means have from time to time been proposed and employed ; such as the addition of alum, sulphuric and other acids, chloride of lime, &c. ; but it is evident that chemical reagents cannot effect the object ; but if even they did, their use is always unsafe, for their continuous and daily absorption might, and doubtless would, cause accidents of a more or less serious nature, not to speak of the trouble and care i-equired in making such additions. Liebig said with both authority and reason, that, as a general rule, the use of chemicals should never be recommended for culi- nary (or food) purposes, fopchemicals are seldom met with in commerce in a state of purity, and are frequently contaminated by poisonous substances. On the other hand, the percola- tion through perforated barrels or coarse sieves, porous substances, plaster, chalk, sand, &c., the pumps, ventilators, bellows, agitators, which have been proposed to aerate the distilled water obtained, and render it palatable, are slow in their action, of a difficult, inconvenient, or impossible application ; and as to leaving the distilled water to become aerated by the agitation imparted to it in tanks or casks by the motion of the ship, this must be continued for a length of time, proportioned of course to the vigor of the oscillations imparted to the ship )iy the violence of the waves, and the time tluis required is always considerable ; yet in this way, and finally by pouring the water several times from one glass to another before drinking it, it may become fully aerated, but without entirely losing its vapid and nauseous taste and odor, and in fact the report of the correspondent of TJlb Times, above alluded to, shows that this method is attended with but indifferent success. I shall presently explain why no system or method of aeration whatever could be attended with success, in the pro- duction oi perfect fresh water from salt water, notwithstanding the great ingenuity displayed in their endeavors to realize the object in view l)y persons who, some of them at least, though of consummate skill as engineers or philosophers, or as men of general knowledge, were not, it would appear, sufficiently well acquainted with the exact nature of the difficul- ties which stood in the way, or were not fitted for the investigation and conquest thereof. In reality the failures in this respect have been due to the fact that the aeration of the dis- tilled water, instead of being, as everybody thought, the whole problem, is only a part of it ; and we shall see, moreover, that the said aeration, to be effective, must be practised under certain conditions, in a certain manner, and is oidy a preparatory step, though an all-impor- tant one, to the final production o^ perfect fresh water. But before proceeding further, it may not be amiss to say a few words respecting another condition in the construction of marine condensing machines, which, from not being suffi- ciently taken into account, frequently puts them suddenly out of service, or necessitates con- stant repairs. I am alluding to those condensers the joints of which arc made by soldering or brazing ; for the different rates of expansion and contraction of metals by heat and by cold, during tlie intervals of work and of rest of the apparatus, would be sure eventually to cause the soldered jiarts to crack and give way, an clTect which the motion of the ship would of course greatly promote. This in f ict was the cause of the accident which about thirty- five years ago put the lives of Captain Freycinet and of his crew in fearful jeopardy. On WATER, SEA. 1079 the other hand, the electro-chemical action which sets up between the metals of the solder and that of the condenser, corrodes the latter, and iu either case a leak being started, the sea water penetrates through it into the apparatus, which may thus be at ouce put out of service after a few months' working, its unsoundness thus creating the most distressing suf- ferings, and putting the lives of all on board in imminent peril. It may therefore be most truly asserted that any fresh-water distilling apparatus, for marine puri)oses, in any part of which solder is employed, is ipso facto defective, and ought not to be trusted, the soldered parts being sure to give way from the causes just alluded to. Lastly, another condition often lost sight of (although of extreme importance,) iu the endeavors which have been made to accomplish the object in question, is to obviate or prevent the deposit of saline matter which takes place when the limit of saturation has been attained, and wliich in a short time interferes, temporarily at least, and often permanently, with the working of the apparatus, renders frequent repairs necessary, and iu all cases eventually destroys it. The question which had been hitherto left unanswered, and yet which must be integrally solved before success could be hoped for, is the following : — To obtain, with a smarll proportion of fuel, large quantities of fresh, inodorous, salubri- ous aerated water, without the help of chemical reagents, by means of a self acting and compact apparatus, capable of being worked at all hours, under all latit^ies, in all* weathers and conditions compatible with the existence of the ship itself, and incapable of becoming incrusted, or of otherwise going out of order. How this complex and difficult problem has been solved I will now proceed to explain : — It is a kuown property of steam that it becomes condensed into water again, when- ever it comes in contact with water at a temperature lower than itself, no matter how high the temperature of that condensing water may be. It is known that the sea and other natural waters are saturated with air containing a larger proportion of oxygen and of carbonic acid than the air we breathe. In effect, 100 volumes of the air held in solution in water contain from 32 to 33 volumes of oxygen, whereas 100 volumes of ordinary atmospheric air contain only 2-i volumes of oxygen. Again, ordinary atmospheric air contains only ',4000 of carbonic acid, whereas the air held in solution in water contains from 40 to 42 per cent, of carbonic acid. The experiments which I undertook iu 1849-50, with a view to determine the amount of these gases present in water, showed me that this amount varied with the state of purity of the water , that, whilst ordinary rain water contains, on an average, 15 cubic inches of oxygenized air per gallon, constituted as follows: — * Carbonic acid - 6-26 Oxygen - - 5'04 Nitrogen 3-70 15-00 sea water, owing to the various substances which it holds in solution, contains only on an average 5 cubic inches of gases, more than one half of which is carbonic acid ; or, in other words, 1 gallon of sea water contains about two thirds less gases than ordinary rain water, and one half less gases than river water. I have also ascertained that air begins to be expelled from such natural waters when the temperature reaches about 130° Fahr. ; and we know that when the temperature reaches 212' Fahr., all the air which it contained has been expelled, and it is for this reason that distilled water contains no air. At that time I shared the prevalent opinions of all who had interested themselves on the subject, namely, that the flat, disagreeable, and mawkish taste and odor of distilled water were due to its having been deprived of air; and knowing that the various methods adopted or resorted to for aerating distilled water by forcing atmospheric air into it had failed, and that the distilled water thus aerated spontaneously or by mechanical means, retained the abominable taste and odor just alluded to, and remained for a long time almost undrinkable, I thought that the defect was possibly owing to the air mixed with it not being of a suitable quality, the experiments which I have related having indeed shown that the composition of air contained mrturally in water differed essentially from atmospheric air; and that con- sequently if I could reintroduce into the distilled water the carbonic acid and oxygen of which ebullition had deprivecl it, it would then become as sweet as good ordinary water. With this view I contrived the apparatus which forms the subject of the present article. The apparatus is represented infirjs. 083, C86. It consists of three principal i)arts, an evaporator, 14, a condenser, G, antl a refrigerator, 3, joined so as to form one compact and solid mass, screwed and bolted, without soldering or brazing of any kind. The evaporator is a cylinder, partly filled with sea water, into which a sheaf of pii)es are immersed, so that on admitting steam at a certain pressure into these pipes it is condensed into fre.-^h, though non-aerated water by the sea water by which the pipes are surrounded, that sea water being thus heated and a portion of it evaporated at the same time ; for it is one of the properties of steam to be condensed by water, no matter how high the temperature of thnt v.-ater may 1080 WATER, SEA. be, if it be only inferior to that of the steam. This non-aerated water becomes aerated, a\ I shall explain presently. On board steamers, the steam is obtained directly from the boil- ers of the ship ; in sailing vessels it is procured from a small boiler which may, or may not be connected with the hearth, galley, or caboose. The steam at a pressure being, of couvtie, hotter than ordinary boiling water, serves to convert a portion of the water contained in the evaporator into ordinary or no-pressure steam, which, as it reaches the pipes in the condenser 6, is resolved therein into fresh aer- ated water. The manner in which it becomes aerated will be exi)lained presently. By thus evaporating water under slight pressure, one fire performs double duty, and tlms the first condition, that of economy, is completely fulfilled; ibr while, in the usual way, 1 lb. of coal evaporates at most G or 7 lbs. of water, the same quantity of coals, burnt under the same boiler, but in connection with my apparatus, is thus made to evaporate 12 or 14 lbs. of water ; or, in other words, from the same amount of coals or of steam employed, the ma- chine which I am describing will produce double the quantity of fresh water that can be obtained by simple or ordinary distillation ; that is to say, double the quantity obtained by the ordinary condensers. The comparative trials made in 18.59 on board II. M. ships the S{)hynx, Erebus, and Odin, at Portsmouth, before the Commissioners of the Admiralty, have most conclusively proved the [jcrfcct accuracy of that statement. The steam issuing from the evaporator, and which is condensed by the water in the con- denser, imparts, of course, its heat to the sea water in it ; and as this water is admitted cold at the bottom, whilst the steam of the evaporator is admitted at the top of the condenser, the water therein becomes hotter and hotter gradually as it ascends, and when it finally reaches the top its temperature is about 208° Fahr. I have already stated that water begins to part with its air at a temperature of about 130' Fahr. ; therefore the greater portion of the air contained in the water which flows constantly and uninterruptedly through the condenser is thus separated, and led thiough a pipe into the empty space left for steam room within the evaporator, where it mixes with the steam. Now, as about six gallons of sea water must bo discharged for every gallon of fresh water which is condensed, and as each gallon of sea water contains, as we said before, 5 cubic inches of air, and whereas the utmost quantity of it that fresh water can natuially absorb is 15 cubic inches per gallon, it follows that the steam in the evaporator, before it is finally condensOT, has been in contact with twice as much air as water can take up, the result being a production of fresh water to the maximum of aeration, that is, containing as much air as in pure rain water. This aeration of the water to the maximum and with the air naturally contained in the water in its original state, though a condition of the utmost importance, as will be seen presently, having, to my extreme surprise, failed in removing the detestable odor and taste in question, it I)ccame necessary to try to discover whence came that flavor which no means of aeration could destroy, except after a considerable length of time, and even tlien never perfectly. With that view I took 25 gallons of distilled water, possessing the characteristic empyreumatic odor and taste, and having evaporated them slowly at a temperature much below the boiling point, I found, at the end of six weeks, the inside of the little platinum dish into which the experiment had finally been carried, covered with a thin oily film of a most disagreeable odor, and upon rinsing the little dish in 25 gallons of excellent ordinary fresh water, the latter immediately aci|uired the empyreumatic odor and flavor peculiar to distilled water, which odor and flavor are evidently due to the destructive action of the heat- ed surface of the vessels in which the water is boiled on the organic substances which are always floating in the air, or those indescriliable particles of dust which are seen playing or moving about in a sunbeam, and which have been dissolved or taken up by the water before its distillation. That water has the power of absorbing and dissolving organic matter in this way is, of course, well known; but it may be illustrated in a veiy simple manner, as follows : — If water, from whatever source, be distilled, the distillate will, of course, be fresh water, pure fresh water, but it will have a peculiar, nauseous, and empyreumatic taste and odor, stronger in proportion as the heat ajjplied to evaporate it has been more elevated ; it is that smell and taste wliich render it undrinkable for a while. If, wb.cn it has become sweet again liy long standing, which period may be hastened by agitation in the atmos- jihere ; if, I repeat it, that distilled water be then redistilled, the di.stillate will lie fouml to have acquired again the same empyreumatic taste and odor as when it was first distilled. How is this? Because it will, by standing or agitation, have redissolved a portion of the air in the room in which it was kept, and along with that air it will have absorbed whatever substances were present, dissolved or susjiended in it, and those substances by their contact with the heated surfaces of the still, yield an empyreumatic product, which taints the distil'.iite. On board ships, the water which is stored in lor the use of crews in the usual way, in the course of about a fortnight becomes putrid and almost undrinkable, because the organic matter which that water contains is undergoing putrefactive fermentation. But about a month or so afterward the water gra have completely disappeared ; all its combustible parts, that is to say, all those parts w.iich would have been burnt off if the tree had Ijcen set fire to, have vanished, and been volatilized, nothing being left behind l)ut the incombustil)lc parts, that is to say, the earthy constituents of the tree. Whether the tree is destroyed l>y actual burning or by sjiontnue- on.i deca'j, the rosult is the same ; the only difference is, that in the first case the combustion is rapid, and is energetically accomplished, with disengagement of heal and of light, in a few hours ; in the second case, the combustion is slow, without sensible elevation of tem- perature, and a period of thirty, or perhaps forty years may be rciiuired to accomplish it, and for the tree to disappear completely : it is only a question of time ; whether the ti ee is burnt in afire, or allowed to decay in the air, the final result is the same; the carbon and hy- drogen of its wood being oxidized, or l)urnt by the oxygen of the air, give, the one carl)()nic acid, the other water, both of which disappear, and a fixed residue, namely, asltcs, remains. Uiit if, instead of leaving the tree whole, it be cut into pieces, into sliavings, into fragments of shavings, into shreds — then its coinl)ustion in a fire will be comi)leted in a few moments; oi' spontancou.sly in a few months, as indeed is the ca.se with farm-yard manures, winch are .spread on tiie ground, and of which notinng remains in the ensuing year — nothing liut the iucombustifile pari thereof — the earthy portion, the ashes, mixed with the soil. — How is it tlial a corpse which, while putrefying, evolves a revolting odor, l)ecomes inodorous when it is put into a hole in the ground, covered with earth, wherein it contiinies nevertheless to decay and to rot, so entirely and eflectualiy, that irtler a certain time nothing remains but 1082 WATER, SEA. bone?, or the earthy matter of those bones ? What has become of the muscles, of the fat, of the nerves, tendons, tissues of all kinds"? They have been burnt, oxidized, converted into carbonic acid and water ; the sulphur thereof has been converted into sulphuretted hydrogen, and that again into sulphuric acid and water ; the nitrogen has been converted into ammonia, &c. &c. Whence it is seen, that all dead organic matter is eventually burnt up by the oxygen of the air ; and that this combustion, whether rapid or slow, is accelerat- ed by the greater or less degree or state of division in which it is exposed to the action of that gaj?. Now Dr. Stenhouse, several years ago, I believe, foimd that the power which charcoal possesses of purifying tainted air is owing to its burning in an insensible manner the sub- stances to which the bad odor was due ; and acting, therefore, upon this discovery, I con- ceived that in order to burn a substance spontaneously in that manner, it mattered not whether the oxygen of the medium into which the said substance was placed was a mixture of oxygen and nitrogen, (atmospheric air,) or a mixture of oxygen and water, (water aerated by my process,) since oxjigen alone was the supporter of combustion, the vitroffen having nothing to do with the burning of the substance, any more than the prater of the aerated water. And accordingly, on experimenting in that direction, I found that charcoal has the power of destroying the empyreuma of distilled water u-/ie7i such uatcr is AJiitATED, Ijjat is to say, when it contains free oxygen. I found by experiments, performed on a somewhat extensive scale for many months, that two cubic feet of charcoal are sufficient to remove entirely the empyreurnatic odor and taste of distilled water, produced at the rate of 500 gallons por diem, and that the charcoal iiever icants reneicing. because it does not act as a filter, but as afire grate, the substance burnt being the empyreumatic product, and the re- sult of the slow combustion thereof being the ordinary products of combustion, to wit, car- bonic acid and water. I have every reason to believe, from the length of time during which several of my apparatuses have been in operation, both on board a large number of ships and on land, that such a filter once made will last for ever, because the charcoal dis- infects the water, so to speak, as it docs air, not by mechanical separation, but by actual, though insensible combustion. The water as it issues from the apparatus is perfectly sweet, tasteless, inodorous, and saturated with its proper and normal quantity of oxygenized air and carbonic acid ; it is of sparkling clearness, and being refrigerated in traversing the sheaf of pipes of the refrigerator 3, surrounded by cold sea water at the lower part of the apparatus, it is fit for immediate use. These qualities I sincerely affirm are not in the slightest degree exaggerated, and a multitude of testimonials establish in an incontrovertible manner that such is truly the case. And thus is the second condition, that of aeration, of digestibility, of wholesomeness accomplished, whereby the fresh water produced is rendered at once not only drinkable, but so sweet, limpid, and fresh, that it cannot be distinguished from the very best spring water. During the experiments or comparative trials which took place at Portsmouth in 1859 before the Committee of the Admiralty, between my apparatus and that of the late Sir Thomas Grant, with which all H. M. steam ships were then provided, a very curious pheiK)m- enon took place, which corroborated in a startling manner the explanation which I have given of the nauseous odor of ordinary distilled water. The circumstances under which the phenomenon was produced were as follows : — On the 20th of October, 1859, steam having been got up in one of the boilers of IT. M. ship "Odin," that steam was turned in precisely equal quantity to each of the apparatuses under trial, (Sir T. Grant's and mine.) The first experiment was completed about 3-30 of the ensuing morning. The fire was then " banked up" for the rest of the night ; the gen- eral steaincock supplying the steam to both apparatuses was turned off; both apparatuses of course became quite cold, and the residuary steam in the boiler was used by the engineer for working his donkey pump. Toward 12 o'clock of the cu.suing day the experiments were resumed ; steam again got up for the purpose, and an equal quantity of it turned as before into each apparatus. When, however, a Ijoiler is not at work, or has been even a few hours without working, its steam room as well as the steam pipe is of course filled with common air instead of with steam ; wherefore the steam which is at first generated in the said boiler, instead of being steam only, is a mixture of steam and air. Accordingly when steam is at first turned into my apparatus, a small cock with which the latter is provided is simultaneously opened for the purpose of allowing an escape for that air which otherwise would to a certain extent interfere with the condensation of the steam, and retard the boiling of the sea water in my evaporator. In conformity with this practice, as soon as the steam from the ship's boiler was turned into both apparatuses, (Sir T. Grant's and mine,) the small cock above alluded to wa-4 opened, whereupon a rush of air escaped through it as usual ; but I then observed for the first time that this air escaping from my cold apparatus, (for no steam had as yet come into it,) instead of being merely atmospheric acid, was an inflammable gas, which, being • brought in contact with a lighted lamp,burut with a thin bluish flame, due evidently to the pres- ence of carburetted gases resulting from the decomposing action exercised by the heated sur- WATEK, SEA. 1083 faces of the boiler, not only on the organic matters naturally contained in all natural waters, as discovered by the experiments which I made in 1850, and to whicii I have already alluded, but also on the fatty matters of the packings of the pistons, and introduced into the boiler by the feed pump, but in all probability principally from the decompostion of the melted tallow which is generally forced in it by means of a syringe ad /loc, for the i)urpose of pre- venting "priming," which introduction, in my humble judgment, is not under certain circum- stances altogether free from danger. I believe that most of the boiler explosions unsatisfsictorily explained or absolutely un- accounted for are referable to the presence of the gases above alluded to, and of atmospheric air, in such proportions as to form a detonating mixture, which is then inflamed, possibli/, by the unduly heated surfaces of the boiler above the water level, but in my opinion nmch more probably by the electricity resulting from the friction of the vesicular steam against the steam pipe and other surfaces. In ettect, it is well known that the steam which issues from a boiler is always highly charged with electricity, and that electric sparks several inches in length may and have been drawn from it, especially when the boiler happens accident- ally or otherwise to be isolated. On the other hand, a mixture of these gases may be exploded when mixed with atmospheric air, in certain proportions varying between 1 of the former and from 6 to 10 of the latter, the maximum effect being when 1 of carburetted hydrogen is mixed v.'ith 8 of atmospheric air. Given, therefore, the conditions of a suf- ficiently insulated boiler, and a mixture therein of the above-mentioned gas and atmospheric air in proportions ranging between one of the first and six, seven, eight, or nine of the second, an explosion of the boiler, of a more or less formidalile nature, may take place. I have already stated that sea water contains salt in the proportion of about 1 lb. to 33 lbs. of water. Now when sea water is evaporated, all the steam produced therefrom being of course fresh water, all the salt which that water contained is left behind, that is to say, the salt previously contained in the evaporated portion is left in that portion which is not yet evaporated, and which is therefore more impregnated with salt than before. If this salt be not i^emoved, and the evaporation is continued, it goes on accumulating, furring and incrusting the vessel, and very soon destroys it. Tliis is, in fact, an inconvenience common not only to all the sea-water stills hitherto contrived, but to the boilers of marine engines ; for no boiler is safe from incrustation as soon as about one half of the sea water admitted into it has been evaporated ; that is, as soon as the sea water has been saturated by con- centration so as to contain 1 lb. of salt in about 16 lbs. of water. My apparatus is not liable to these incrustations or deposits of salt, because the sea water circulates in it in a constant and uninterrupted manner, a discharge taking place at the same time through cock 45, {socjic/. 685,) so as to leave the sea water in the apparatus superabundantly diluted to hold in perfect solution the whole of its salt ; in fact, the sea water discharged through that cock contains only about one half per cent, more salt than it did when it first entered the apparatus, which is a perfectly insignificant increase. The different parts of the apparatus being made of sheet, riveted, galvanized iron plates and of cast iron, connected in a substantial manner by screws and bolts, without soldering or brazing of any kind or in any part, it is perfectly impossible that it should go out of order by any accident short of those cases of force majeure which, unfortunately, arc too often the cause of the ruin or wreck of the ship itself. I shall now give a description ofthefir/s. 685 and 68G, in which the same numbers rep- resent the same organs. Fir/. 685 is a section on the same plane, showing tiie mode of action of the apparatus, without reference to the real position of its constituent parts. Fig. 686 is a correct front elevation of the apparatus. 1 shows the large entrance tube for the sea water : this tube is connected to a lai-gc cock, communicating with the sea through the side or bottom of the ship ; or else flanged to a much smaller pipe connected with a pump, by means of which the ajjparatus is su])plied with water from the sea, which thus penetrates into the refrigerator 3, through the tube of communication 4, and thence passes round the slieaf of pipes 15, in the said refrigerator, tin-ough another communication tube 5, into the condenser 6, as shown by the arrows, and up the large vertical tube 8, whence the surplus sea water pumped up Hows away through the pipe 9, in the direction indicated by the arrows. Tiie condenser 6 being thus com- pletely filled up with sea water, on opening the cock 10, the sea water jiassing tlnough i)ipo 11 falls into the feed and priming Irox Iti, and thence tlu-ough pipe 13 into the evaporator 14, filling it up to a certain level, regulated by opening or shutting the cock 10 so as to maintain the sea water at tlie proper level in the evaporator 14. 3, Rcfricfcrator. It is a hoi'izontal case pervaded with pipes, 15, placed horizontally in it. The sea water, being introduced into this refrigerator, circulates round a sheaf of jiipes 15, held between the caps 16, at each end of the .saio 25 into the steam trap 26, thence along pipes 29 and 31, and tin-ough the cock 41, into the other portion of pipes 15 of the refrigerator 3. The condensed water from the pi|)es 23 of the evaporator 14 be- comes aerated by the excess of air contained in the condensed water of the pipes 17 of the condenser, in its passage with the latter through tlie pipes 15 of the refrigerator 3, in traversing which the con»bined waters are cooled down to the temperature of the sea water round the said sheaf of jiipes in the refrigerator. And tlie result is, that after passing through the filter, it flows at 34 in tiie state of perfectly cold fresh water, thoroughly aerated, and of matchle.-JS f|uality. 20, level to which the .sea water rises in the aerating pipe 10. 21, pipe conducting the mixture of .'^team and air from the feed and priming box 12 into the sheaf of pipes 17 of the condenser G. 22, pipe leading the mi.xture of steam and air from the evaporator 14 into the feed and priming box 12, where any salt water, with wliii'h it may be mixed, is arrested and returneti to the evaporator 14, through pipe 13, wiiile the pure steam, piu, its further progress being intercepted by cock 41, which is shut, as said before. As soon as the condensed water flows out in a "clear state from,coek 40, shut it, and open cock 41, so that it may pass into the pipes 15 of the refrigerator 3, and out at cock 42. In a few moments the con- densed water will flow out in a clear state from that cock 42, which should then be closed, opening at the same time cock 32, so that it may pass into the filter 33. But the steam within the sheaf of pipes 23 of the evaporator 14 soon brings the sea water round them to the boiling point, and converts part of it into steam. This pure sec- ondary steam from the evaporator, issuing then from the priming box 12, passes through pipe 21 into the pipes 17 immer.sed in the salt water of the condenser 6, and being con- densed in the said pipes, is allowed to flow out at the cock 38 (which has been opened at start- ing) as long as it is not clear. In a short time, however, it will flow out from that cock, 38, in a perfectly clear state; when this takes place shut this cock 38, and open cock 3p, whereupon it will flow into the pipes 15 of the refrigerator 3, in which pipes it will mix with that coming from the pipes 23 of the evaporator 14, and flow with it through the .said pipes 15, and thence into the filter 33 through the cock 32, the whole issuing finally from the filter 33 through pipe 34, in the state of perfect aerated fresh water. From this brief description of my marine fresh-water apparatus it may be Been that a quantity of fresh water is produced always double that which can be evaporated from any boiler whatever, and indeed by increasing the number of evaporators lib. of coals may thus be made to yield 30 or 40 lbs." of fresh water of matchless quality ; that the small volinno of the apparatus, the large quantity of fresh aerated water which it produces,* at an ex- tremely small cost, its perfect safety, permanent order, and the case with which it can be disconnected and all its parts reached, not only render it preeminently suited to naval pur- poses, but likewise to such stations or places as are deficient in one of the first necessaries of life, saluljrious fresh water, or where it cannot be obtained at all, or only in an insuffi- cient, precarious, or expensive manner. — A. X. The following letters were addressed to the Editor in reply to an inquiry made by him as to the value of Dr. Xormandy's invention. "Government Emisration Board, 8 Park Street, "Westminster, 1st March. T^fiO. "Sir,— I am directed by the Emigration Commissioners to acknowledge the receipt of yr)nr letter of the ^Sth ultimo, requesting to be furnished with any evidence they may posses.s as to the good or ill effects of the use of Dr. Normandy's distilled water on board emigrant ships. " In replv. I am to acquaint you that the Commissioners have placed on bo.ard several of their emi- grant ships, Dr. Normandy's api>aratus for distilling fresh fnim salt water, and that the reports which they have as yet receivedfrom their surgeons in those vessels (who are instructed to pay particnhir attention to the matter) are uniformly of a favor.ible character — one gentleman onlv having mentioned that the water had at first an insipid t.oste which subsequently went otf. Tiiis probably arose fn>m some accidental circumstance in the particular machine, as freedom from insipidity is one of tbo main char- acteristics of the water. "I enclose, for your information, extracts from the official reports made to this Board by their sur- geons and the colonial emigration aironts, respecting the quality of the water and its effects. '• I have the honor to be, sir, your obedient servant, " Robert Hunt, Esq." " S. Walcott, St'cretary." Extract from the report of Dr. Duncan, Immigration Afjcnt, on the ship " Cotifance," dated Port Adelaide, Jan. 10, 1859 : — "A distilling apparatus, invented by Dr. Normandy, was sent out in the 'Conflancc' to test its ofll- ciencv. "There arc two great objections to water distilled in the ordinary manner; the first Is, that water thus obtained is without air, is unp.al.atable and indi^'cstible: the second is, that it contracts, while in tho process of distillation, ar -iiipyrcuuiatic odor and taste; in fact, ordinary distilled water is 6aid to bo indigestible and nauseou.^. "These two objections ai.pear to be perfectly met bv Dr. Normandy's invention ; tho water obtain«d by his proces.s is perfectlv palaUitde. well aerated, and devoid of smell. "During the passage of the ' Confiance,' nearly eleven thousand ga'lons of water were distilled, and is reported by Mie surgeon .superintemlent to have been of most excellent quality, and preferred by tho emigrants to tho water shipped on board in casks." ♦ An apparatus 4 ft. 6 in. high, 5 ft. long, and 2 ft. wide, produces at least 24 gallons of fresh water per hour. 1088 WEAVING BY ELECTRICITY. Extract from the Report of Dr. Carroll on the ship " Comcai/,^^ dated Melbourne, Sept 20, 1858:— "The qualitj- of the water produced was, in my opinion, excellent, and most aereeablo in taste; and, so far as my observation went, most wholesome ; in fact, during the hot weather I considered it quite a luxury ; and I regrettcil much that the quantity produced was not greater. It was also preferred by tho passengers to the ship's water." Extract from the Report of Br. Crane 07i the ship ^^ Forest Monarch,''^ dated Sidney, Jan. 5, ISoO : — " The condensed water wa.s very good, excelling in clearness and purity, and much more palatable than any water I had ever previously seen on board ship, being not unlike the rain water so much esteemed in the West Indies. The water, as it came from the ajiparatus, possessed a slight peculi.ir taste, which varied in degree with the purity of the sea water employed in its production, and -which disappeared on exposure to the air. This peculiar taste I attribute partly to the excessive aeration of the condensed water, as I have noticed a similar taste in .soda water that has been adulterated for ehiap- ne.^s' sake, with common air, and partly to empyreuniatic products obtained from the destructive dialil- lation of organic impurities contained in the sea water subjected to distillation." Extract from the Report of Dr. Rivers on the " Morayshire,'''' dated Calcutta, May 18 1859:— " The emigrants did not at first like the distilled water, but gradually got accustomed to it, and after- ward to preler it to the ordinary water. Those drinking it seemed better in he.alth than the pe( pie using the otlier water, and more free from bowel complaints. 1 Avould, therefore, stiongly recommend that the water prepared from Dr. Normandy's apparatus be generally used in all ships carrying Coolies, as, in my opinion, it is not only wholesome, but perfectly free from all impurities, besides not so liable to disorder the bowels as the common water." Extract from the Report of Mr. James Crosby, Immigration Agent at British Guiana, on the ship " Queen of the East," dated British Guiana, Oct. 19, iS59: — " I found also Dr. Normandy's admirable distilling apparatus in full operation. It is almost impos- sible to spiak in too favorable terms of this apparatus, capable of producing five hundred gallons a day — ■with the consumption, I think, of only eight bushels of coals— of water apparentlj- as pure and whole- some as could bo drunk, and taken from alongside the ship, from the muddy and impure M-ater of tno Demerara river." Extract of a letter from Dr. L. S. Crane, surgeon superintendent of the ship '■'■Devon- shire," dated Coconada, Dec. 27, 1859 : — The "Devonshire" was dismantled in a hurricane, by which the apparatus on deck was injured. " Since the water apparatus was broken, the health of the Coolies has deteriorated. After careful observation I can find no other cause for the dysentery and diarrhoea prevailing than the water they drink. The ventilation is excellent, the between-decks have been kejit beautifully clean and dry— the food is good and well cooked. The rice (cargo) has been steaming to a certain extent, but the diseases that arise from bad air, — low fevers and cholera, — have not made their appearance. Hesides, the crew have suffered very much more than the Coolies, and the only condition common to both is the water they drink." Extract of aletter from Mr. C. Chapman, surgeon superintendent of the ship '■'Euxine," to S. Walcott, Esq., dated Madras, Jan. 23, 18C0: — '•In my opinion, the water it (Dr. Normandy's apparatus') produces is perfectly sweet and whole- some ; is far preferable, and preferred by all hands, to the water in tanks or casks." WEAVING BY ELECTRICITY. The article Weaving, and tho.«e referred to from it, togctlier with the article on the Jacquard loom, will render the conditions necessary to the production of figures in any textile fabric tolerably familiar. A brief notice of a new inven- tion for employing electricity in weaving cannot fail to be interesting. So long ago as 1852, M. Bonelli constructed an electric loom, which was exhibited at that time in Turin, but the first trial to which the machine was submitted gave but small hope to those who saw it tliat the inventor would succeed in his object. The public trial at Turin, in 1853, in the presence of manufacturers, was not so successful as to remove all doubts as to the merits of the novel apparatus. In the following year it was submitted to the judgment of the Academy of Sciences at Paris, who appointed a committee to examine it, ))Ut it is believed that no report was ever made. In 1855, a model of the loom had a place at the Universal Exhibition at Paris, but the lateness of its arrival there prevented any official report being made in reference to its merits. Since then, M. Bonelli has devoted much time and attention in endeavoring to remedy its defects and to perfect its working, so as to render it capable of holding its j)lace in the factory. This M. Bonelli believes he has at la.st accomplished, and he has brought over to this country, not merely a model, but a loom in complete working order, which he is prepared with confidence to submit to the judgment of manufacturers, as a machine which, from its economy and efficiency, may be put in favorable comparison with the Jacquard loom. In the first place, it mu^st be understood that the special object of M. Bonelli's machine is to do away with the necessity for the Jacquard cards used to produce the pattern at the present time, the source of delay and very considerable cost, more especially in patterns of any extent and variety of treatment. JI. Bonelli uses an endless band of paper, of suitable width, the surface of which is covered with tin foil. On this metuilizcd surface, the required WEAVING BY ELECTRICITY. 1089 pattern is drawn, or rather painted with a brush in black varnish, rendering the parts thus covered non-conducting to a current of electricity. This band of paper, bearing the pat- tern, being caused to pass under a series of thin metal teeth, each of which is in connection with a small electro-magnet, it will readily be conceived that as the band passes under these teeth a current of electricity from a galvanic l^attery may be made to pass through such of the teeth as rest on the metallized or conducting portion of the band, and from such teeth, through the respective coils, surrounding small bars of soft iron, thus rendering them tem- porary magnets, whilst no current passes through those connected with the teeth resting on the varnished portions. Thus, at every shift of the band, each electro-magnet in connection with the teeth becomes active or remains inactive according to the varying portion of the pattern which happens to be in contact with the teeth. In a movable frame opposite the ends of the electro-magnets, which, it should be stated, lie in a horizontal direction, are a series of small rods or pistons, as M. Bonelli terms them, the ends of which are respectively opposite to the ends of the electro-magnets. These pistons are capable of sliding horizon- tally in the frame, and pass through a plate attached to the front of it. When this frame is moved so that the ends of the pistons are brought into contact with the ends of the electro- magnets, they are seized by such of them as are in an active state, and on moving the frame forward, those are retained while the others are carried back with it, and, by means of a simple mechanical arrangement, become fixed in their places ; thus there is in front of the frame a plate, with holes, which are only open where the pistons have been withdrawn, and this plate, as will be readily understood, acts the part of the Jacquard card, and is suitable for receiving the steel needles which govern the hooks of the Jacquard in connection with the warp threads as ordinarily used. The ordinary Jacquard cards are shown in the following wood-cut, fifj. 687. Instead of this arrangement, which will be understood by reference to the article Jac- quard, M. Bonelli, as we have said, instead of the cards prepares his design on metal foil, in a resinous ink, which serves to uiterrupt the current, and thus effect the object of the ma- chine. Fi(]s. 687 and 688 explain generally the arrangements by which the process is effected. A, /^f. 688, represents the plate pierced with holes, which j)Iays the part of the card. Each of the small pistons or rods i, forming the armatures of the electro-magnets r, has a small head, r/, affixed to the end, exactly opposite the needles c,fi(U 687, of the Jacquard, and are capable of passing freely through the holes of the plate a, /f^. 688. At a given Vol. III.— 69 L 1090 WEAVING BY ELECTRICITY. moment the plate is slightly lowered, which prevents the heads of the pistons passing, and the surface of the plate then represents a plain card. The pistons are sujjported on a frame, //, which allows them to move horizontally in the direction of their length. At each stroke of the shuttle, the frame, carrying with it a plate, a, has, by means of the treadle, a reciprocating motion backward and forward, and in its backward movement presents the end.s of the pistons to one of the poles of the electro-magnets, and, by means of certain special contrivances, contact with the magnets is secured. When the frame f f returns with the j)late a toward the needles of the Jacquard, the electro-magnets, which become temporarily magnetized by the electric current, hold back the pistons, the heads of which pass through the plate a, and rest behind it. On the other hand, the electro-magnets which arc not magnetized, owing to the course of the current being interrupted, permit the other pis- tons to be carried back, their heads remaining outside the plate and in front of it. At this moment, the plate, by means of an inclined plane beneath it, is lowered slightly, thus pre- venting the heads of the pistons passing through the holes, by the edges of which they are stopped, so as to push against the needles of the Jacquard ; on the other hand, the heads of the pistons which have passed within and to the back of the plate, leave the correspond- ing holes of the plate free, and the needles of the Jacquard which are opposite to them are allowed to enter. The electro-magnets are put into circuit in the following manner : — One of the ends of the wire forming the coil of each of the magnets is joined to one common wire in connec- tion with one of the poles of a galvanic battery. The other end of the coil wire of each magnet is attached to a thin metallic plate, w;, having a point at its lower extremity. All these thin metallic plates are placed side by side, with an insulating material between them, formed like the teeth of a comb, n n. At a given time these thin plates rest with their lower extremities on the sheet bearing the design p, which, in the form of an endless band, is wrapped round and hangs upon the cylinder q, and according as the thin metal plate rests on a metallized or on a non-conducting portion of the design, the corresponding electro-magnet is or is not magnetized, and its corresponding piston does not or does press against the needle of the Jacquard. The wire from the other pole of the battery of course communicates with the band bearing the design, by being attached to a piece of metal, which lies in constant contact with the metallic edge of the band. At b is a contact-breaker, which is put in motion by the movement of the frame. Besides this, by means of a mechani- cal arrangement connected with the treddle, which raises or depresses the griff frame, the band bearing the design is carried forward at each stroke, and the rapidity with which it is made to travel can readily be regulated, by means of gearing, at the will of the workman. r.y regulating the speed of the band, and by the use of thicker or thinner weft, an alteration in the character of the woven material may be made, whilst the same design is produced, though in a finer or coarser material. Such are the arrangements by which the loom will produce a damask pattern, or one arising from the use of two colors, one in the warp and the other in the weft. I will now shortly explain the method adopted by M. Bonelli for producing a pattern where several colors are required. The design is prepared on the metallized paper, so that the colored parts arc represent- ed by the metallized portion of the band, but each separate color is, by removing a very thin strip of the foil at the margin, insulated from its neighboring color. Then all the pieces of foil thus insulated, which represent one color or shade, are connected with each other by means of small strips of tin foil, which pierce through the paper and are fastened at the back, and are conducted to a strip of tin foil which runs along the edge of the band, tliere being as many such strips of tin foil as there are colors. Thus each special color of tlie pattern, in all its parts, is connected by a conductor with its own separate strip of tin foil, and by bringing the wire from the pole of the battery successively into contact with the several strips, a current of electricity may be made to pass in succession through the several parts of the design on the band representing the separate colors of the design. Thus, assuming four colors, 1, 2, 3, 4, there would be four strips of tin foil running the length of the band, insulated from each other, each of which would be in connection with its own separate color only. At any given moment, the thin plates of metal resting on the pattern would touch it in a line which, as it passes over the width of the pattern, would run through all, or any one or more of the colors, but the electric current would pass only through those plates which rest on the one color represented by the strip with which the pole of the battery at that instant happened to be in contact. The inventor claims the following as the results of his invention : — First. — The great facility with which in a very short time, and with precision, reductions of the pattern may be obtained on tlie fabric by means of the varying velocity with which the pattern may be passed under tlie teeth. Second. — That without changing the mounting of the loom or the pattern, fabrics thin- ner or thicker can be produced by changing the number of the weft, and making a corre- sponding change in the movement of the pattern. ^OAD. 1091 T7iird. — The loom and its mounting remaining unchanged, the design may be changed in a few minutes by the substitution of another metallized paper having a difl'erent pattern. Fourth. — The power of getting rid of any part of the design if required, and of modi- fying the pattern. WIRE ROPE. The mianufacture of ropes made of wire, has, of late years, become a most important one. \ot only are ropes of this description now employed in the most extensive coal mines of this country, and for winding generally, but they are used for much of the standing rigging of ships, and for numerous ordinary purposes. Perhaps the most important application of wire rope has been, however, in the construction of the electric cables. See Electro-telegraphy. The following Tables show the relative values of ropes of hemp, iron, and steel. Table I. Hound Wire Ropes, for inclined playies, mines, collieries, ships^ standing rigging, d:c. 1 Hemp. 1 I EON. 1 Steel. E-T StBEXGTH. Circum- lbs. weight Ciream- lbs. weight 1 Circpm- lbs. weight Working Breaking ference. per (athom. ference. per fathom. ference. per iathom. lead. •train. Cwts, Tona. 2f 2 1 1 1 . 6 2 1 1* 1* 1 1 9 3 3i 4 1 1* 2 - 12 4 H 2* u H 15 5 4i 5 U 3 13 6 2 8* 1* 2 21 7 5J 7 2i 4 li 2* 24 8 2i 4J 27 9 6 9 2} 5 ll 3 80 10 2* 5J . S3 11 6* 10 2i 6 2 3* 86 12 24 6* 2J 4 89 13 T 12 24 7 2J 41 42 14 ! 3 71 45 15 7i 14 3| 8 1 2i 5 43 16 SJ Si 51 17 8 16 sf 9 2* 51 54 IS 3i 10 • 2* 6 60 20 St 18 8f 11 2t 61 66 22 H 12 1 72 24 n 22 3i 13 3} 8 73 26 10 26 4 14 S4 28 4i 15 3| 9 90 80 11 80 4J 16 - - 96 82 4* 13 3J 10 103 86 12 84 4* 20 8t 1 12 120 40 Bound rope in pit sliafts must be worked to the same load as flat ropes. Table II. Flat Wire Ropes, for pits, hoists, cls, wliich are often streaked with purple. The leaves, which are the only part of the plant employed iti dyeing, are large, smooth, ami glaucous, like cabbage leaves, but exhil»it no external imlication of the presence of any blue coloring matter, which indeed, according to modern researches, is not contained in them ready fonn- ed. The plant called by the Romans glaxtmn, with which, according to Pliny, the Britons dyed their skins blue, is supposed to be identical with woad. Before the introduction of 1092 WO AD. indigo into the dvehouse of Europe, woad was generally used for dyeing blue, and was ex- tensively cultivated in various districts of Europe, such as Thuringia, in Germany ; Langue- doc, in France ; and Piedmont in Italy. To these districts its cultivation was a" source of great wealth. Beruiii, a rich woad manufacturer of Toulouse, became surety for the pay- ment of the ransom of his king, Francis I., then a ]irisoner of Charles Y., in Spain. The term pays dc cocaif/ne, denoting a land of great wealth and fertility, is indeed supposed to be derived from the circumstance that the woad balls, called in French cocaiyncs^ were manufactured chiefly in Languedoc. The woad leaves were not employed by the dyer in their crude state, but were previous- ly subjected to a process of fermentation, for the pur])ose of eliminating the coloring matter. The seed having been sown in winter, or early spring, the plants were allowed to grow until the leaves were about a span long, and had assumed the rich glaucous appearance indicative of maturity, when they were stripped or cut off. The cropping was repeated several times, at intervals of five or six weeks, until the approach of winter put a stop to the growth of the [dant. The leaves sent up in the succeeding spring yielded only an inferior article, (called in Gernian A'oinpsoivaid,) and it was therefore customary to keep only as many plants until the Ibllowing year as were required for obtaining seed, which, the plant being biennial, is only produced in the second j-ear. The leaves, after being gathered, were slightly dried, and then ground in a mill to a paste. In Germany it was usual to lav this paste into a heap for about twenty-four hours, and then form it Ijy hand into large balls, which were first dried partially in the sun, on lattice work or rushes, and then piled up in heaps a yard high, in an airy j)lace, l)ut under cover, when they diminished in size and be- came hard. These balls, when of good cjuality, exhibited, on being broken, a light blue or sea-green color. They were usually sold in this state to manufacturers, Ijy whom they were subjected to a second process in order to render them fit for the use of the dyer. This process was conducted in the following manner: — The woad balls were first broken by means of wooden hammers, and the triturated |jaass was heaped up on a wooden floor, sprinkled with water, sometimes with a little wine, and allowed to ferment or putrefy. The mass became very hot, and emitted a strong ammoniacal odor, and much vapor. In order to regulate the process it was frec|uently turned over with shovels and again sprinkled with water. When the heat had subsided, the ma.^s, which had become dry, was pounded, pass- ed through sieves, and then packed in barrels ready for use. It had the appearance of pigeon's dung. In France the paste obtained by pounding the woad leaves was taken to a room with a sloping pavement, open at one end, laid in a heap at the higher end of the room, and al- lowed to ferment for a period of twenty or thirty days. The mass swelled up and often showed cracks or fissures, which were always carefully closed as soon as they appeared, whilst a black juice exuded and ran away in gutters constructed for the purpose. AVhen the fermented heap had become moderately dry, it was ground again and formed into cakes, called in French coqnes, which were then fully dried, and in this state brought to market. In France and Italy a second fermentation was not generally thought essential, but when performed it was conducted exactly in the manner just descril)ed. At the present day woad is nowhere employed alone for the purpose of dyeing blue, since it is found more economical to use indigo, and the cidtivation of the plant has there- fore declined considerably, and has even Ijecome nearly extinct in districts where it was formerly carried on extensively. By woollen dyers, however, it is still used, but only as a means of exciting fermentation, and thus reducing the indigo blue in their vats; indeed, the woad employed by them contains little or no blue coloring matter. See Indigo. Numerous attempts have been made to extract the blue coloring matter from woad, in the same way that indigo is extracted from the leaves of the indigofera in the East Indies and other countries. At the commencement of the present century, when the price of in- digo on the continent of Europe was very high, a prize of 100,OfiO francs was even offered by the French government for the discovery of a method of obtaining from the Isatis tinc- toria, or some other native plant, a dyeing material, which, both in regard to price and the beauty and solidity of its color, should form a perfect substitute for indigo. The expei i- mcnts which were made in consequence served to prove that it was quite possible to obtain genuine indigo from woad leaves, but that the process could never be carried on profitably, on account of the very small proportion of coloring matter contained in the plant. Nine parts of fresh leaves yield only one part of the prepared material or pastel, and the latter does not afford more than 2 per cent, of its weight of indigo. According to Chevreul, the leaves of the Indif/nfrra anil, even when grown in the neighboihood of Paris, contain 30 times as much indigo blue as those of the Isatis iitictoria, and, when cultivated in tropical countries, the amount is probably still higher. The comparatively high price of land and labor would probably itself prove a sufficient obstacle to the successful manufacture of indigo in most European countries, even if the yield were equal to what it is in the tropics. In 1808 Chevreul published the results of his analysis of woad and pastel. It has more recently been made the subject of chemical investigation, for the purpose of ascertaining the state in which indigo blue exists in plants and other organisms. See Ixdigo. — E. S. zmc. 1093 ZINC, METALLURGY OF. RoaMing of Ores.— Blonde, or sulphide of zinc, is, pre- vious to its treatment for metal, carefully roasted in a reverberator)' furnace, over the bot- tom of which it is spread in a layer of about four inches in thickness. A strong heat is necessary for this purpose, and during the operation the charge is frequently stirred with a strong iron rake, with a view of exposing fresh surfaces to the gases of the furnace. The apparatus most commonly employed in this country for roasting sulphide of zinc consists of a reverberatory furnace about 36 feet in length and 9 feet in width, provided with a fire- place of the usual construction. The sole or hearth of this apparatus i.s divided into three distinct beds, of which that nearest the fire bridge is 4 inches lower than that which is next it, which is again 4 inches lower than that nearest the chimney. In addition to the heat derived from the fireplace, the gases escaping from the reducing furnaces are usually intro- duced immediately before the bridge, and a considerable economy of fuel is thcrel)y eHected. When the furnace has been sufficiently heated a charge of 12 cwt. of raw blende is intro- duced into the division nearest the chimney and equally .spread over the bottom, care being taken to stir it from time to time by means of an iron rake, as before described. After the expiration of about eight hours this charge is worlvcd on to the floor of the compartment forming the middle of the furnace, and a new charge is introduced into the division next the chimney. About eight hours after this charging the ore on the middle bed is worked on to the first, whilst that on the hearth next the chimney is equally spread on the middle one and a new charge introduced into the division next the stack. After the expiration of another period of eig'it hours the charge on the first hearth is drawn, the ore on the middle and third hearths moved forward, and a fourth charge introduced as before. In this way the operation is continuous, and each furnace will effect the calcination of about 36 cwt. of ordinary blende in the course of 24 hours. Calamine, or silicate of zinc, is usually prepared for smelting by calcination in a furnace resembling an ordinary lime kiln, the heat being often supplied by means of four fireplaces arranged externally, and so placed that the heated gases may be drawn into it, and regularly distributed through the interstices existing between the masses of ore. Calamine subjected to this treatment commonly loses about one-third of its weight, and is at the same time ren- dered so friable as easily to admit of being reduced to fine powder by an ordinary edge-mill. Reductiox. Beh/ian process. — When this method of treating zinc ore is employed, the furnace rep- resented in fi(/. 6S9 is commonly used. 089 GOO Fir/. 689 represents, on the left hand, a front elevation of the furnace, and on the right a sectional elevation through the ashpit and fireplace, f is the fireplace, whilst a is the cavity into which are introduced the retorts destined for the distillation of the metal. lO'M zmo. The products of combustion escape by the openings g into a flue, by which they are conducted into the calciner for the purpose of economizing the waste heat. These furnaces are either arranged in couples, back to baclf, or in groups of four, for the purpose of ren- dering thft structure more solid, and economizing heat. In the arched chamber a are placed 48 cylindrical retorts, 8 feet 6 inches in length from b to d, and *? inches internal diameter. These are made of refractory fire clay, well baked and supported behind by ledges of masonry, «, 6, fg. 690, whilst in front, at c d, they rest on tire-clay saddles let into an iron framing. Short conical fire-clay pipes, 10 inches in length from (Z to c, are fixed in the mouths of these retorts by means of moistened clay, and project for a short distance be- yond the mouth of the furnace. To these are adapted thin wrought-iron cones 18 inches in length from c to/, tapering off at the smaller extremity to an orifice of about three quar- ters of an inch in diameter. The inclined position of the retorts, the method of adjusting the pipes, and the general arrangement of the apparatus are shown in///. 690, in which r, r, J-, ?•, represent the nozzles of thin wrought iron. When a new furnace is first lighted the retorts are introduced without being jireviously baked, but care must be taken that they be perfectly dry and seasoned, and for this reason it is necessary to keep a large stock con- stantly on hand, in a store house artificially heated by means of "some of the flues of the es- tablishment. The heat is gradually increased during three or four days, at the end of which period charges of ore are introduced, the clay cones are luted in their places, and the furnace is brought into full working order. The charge of a furnace consists of 1,680 lbs. of roasted blende or calcined calamine, and 840 lbs. of coal dust. The ore and coal dust, after deing finally divided and intimately mixed, is slightly damped, and subsequently introduced into the retorts by means of a semi-cylindrical scoop, by the aid of which an experienced workman will eftect the charging without spilling the smallest quantity of the mixture. In this country the retorts in the lower tier are usually not charged, as they are ex- tremely lialjle to be broken, and are therefore only employed to modei-ate the heat of the furnace. On the Continent, however, the fireplace is frecj[uently covered by a hollow arch, and in that case every retort requires a charge of ore. The mixture introduced into the retorts varies, to a certain extent, with their position in the furnace, for in spite of every precaution to prevent inequality of temperature, it is found impossible to heat the whole of them alike, and those next the fire, therefore, from being the most strongly heated, are liable to work off first. As soon as the retorts have been charged the clay cones are luted into their places, and carbonic oxide gas, which burns with a blue flame at the mouth of the cones, quickly makes its appearance. The quantity of this gas gradually diminishes, and as soon as the flame assumes a greenish-white hue, and white fumes are observed to be evolved, the sheet-iron cones are put on, and the fur- nace at once enters into steady action. From time to time, as the iron cones become choked with oxide, they are taken off and gently tapped against some hard substance, so as to re- move it, and then replaced. The oxide thus collected is added to the mixture prepared for the next charge. After the expiration of about six hours from the time of charging the wrought-iron tubes are successively removed, and the metallic zinc scraped from the clay pipes into an iron ladle. This, when full, is skimmed, and the oxide added to that obtained from the nozzles, whilst the pure metal is cast into ingots, weighing about 28 lbs. each. At the expiration of twelve hours from the time of charging the zinc is again tapped, and the residue remaining in the retorts withdrawn. The rctoits are immediately recharged, and the operation of reduction is conducted as above described. The residues obtained from the retorts, after the first working, are passed through a crushing mill, mixed with a further quantity of small coal, and again treated for the metal they contain. The earthen adapters or cones, when unfit for further service, are crushed and treated as zinc ores. In order to work these furnaces with economy, it is of the greatest importance that they should be constantly supplied with a full number of retorts, since the amount of fuel consumed, and the general expenses incurred for each furnace, will be the same if the ap- paratus has its full complement of retorts, or if one-half of them are broken and conse- quently disabled. It is therefore necessary, in all zinc-smelting establishments, to keep a large stock of well- seasoned retorts, which, before being introduced into the furnace, to make good any deficiency cau.sed by breakage, are heated to full redness in a kiln provided for that purpose. The Belgian process of zinc smelting is that M-hich is at present most employed in this country. The principal localities in which zinc ores are treated are Swansea, Wigan, Llannelly, and Wrexham. Silesian procoxx. — In the zinc works of Silesia the furnaces employed differ considerably from those used in the Belgian process. Fifi. 001 represents an elevation, and ///. 692 a vertical section of the Silesian furnace. The distillation is effected in a sort of muffle of baked clay, m, fig. 692, and figs. 093, G94, about 3 feet 3 inches in length, and 20 inches in height. The front of this' imiffle is ZINO. 1095 pierced with two apertures. The lower opening, d, serves to remove the residues remaining in the retorts after each operation, and is closed during the process of distillation l)y a small door of baked clay, firmly luted in its place. In the upper opening is introduced a hollow cliy ar.n, bent at right angles, «, 6, c, and which remains open at c. An opening at b per- mits of charging the retort by means of a proper scoop, and this, during the operation, is closed by a luted clay plug. From six to ten of these muffles or retorts are arranged in rows, on either side of a furnace provided with suitable apeiturcs for their introduction. They are securely luted in their places, and the openings closed by sheet-iron doors, by which the too rapid cooling of the pipe a, 6, c is prevented. The fuel employed is coal, which is burnt on the grate G, situated in the centre of the furnace. The retorts are charged with a mixture of calamine and small coal, or more frequently coke dust, since, when coal i3 employed, the products of distillation are found to be liable "to choke the pipe «, h, c. The zinc escapes by the opening c of the adapter, and is received into the cavities o of the furnace. The furnace shown in 'ficjs. (595, 690, 097, is for remelting the metallic zinc. Fi(). 096 is a front view; fig. 695 is a transverse section, fig. 09*7 a view from al)ove; a is the fire- door ; b tlio grate ; c the fire bridge ; d the tluc ; c the chimney ; /, /, / east-iron melt- ing pots, wliich contain each about 10 cwt. of metal. The heat is moderated by the suc- cessive addition of pieces of cold zinc. The inside of the pots is sometimes coated with loam, to prevent the iron lacing attacked by the zinc. In some establishments, and particularly those at Stolberg in Prussia, the retorts have the form i), represented in fig. 098. C is an adapter also of fire clay ; b a cone of wrought iron, and a a small vessel of the same ma- terial for tlie collection of the oxide, and fur- nislied in the bottom with an aperture for the escape of the gases generated. 698 1096 ZINC. These are arranged on either side of a grate as represented, fig. G99, an internal open- ing serving for two retorts, and of which there are usually twelve in each furnace, e is the fire door ; f grate ; G chamber in masonry of furnace ; u diaphragm of fire brick sup- porting adapter, in the depressed part of which the metallic zinc is collected and subse- quently removed by a scraper, as in the case of the cone of the Belgian retort. The wrought- iron vessel a is supported by a chain or wire J. Fig. VOO represents a longitudinal elevation of the roasting furnace employed. The general consumption of Spelter throughout the world is about 67,000 tons per annum, of which about 44,000 tons are made to take the shape of rolled sheets, and these are estimated to be applied as follows, each quantity being somewhat below the truth: — Tons. Roofing and architectural purposes .... 23,000 . Ship sheathing 3,500 Lining packing cases 2,500 Domestic utensils 12,000 Ornaments 1,500 Miscellaneous 1,500 44,000 Fifteen years ago the quantity used for roofing did not exceed 6,000 tons; none was employed for ship sheathing or lining packing cases, and stamped ornaments in zinc date only from 1852. From the low temperature at which zinc fuses, and from the sharpness of impressions possessed by castings in this metal, it is much employed on the Continent for the production of statues and statuettes. The uses of this metal in the preparation of alloys have already been noticed under the head of alloys. It is also employed like tin for coating iron, pro- ducing what is known as galvanized iron. The disinfectant liquor of Sir W. Burnett is chloride of zinc, and the oxide of this met.al is much employed as a pigment in place of white lead. Zinc or Spelter imports in 1858: — Crude in cakes. Tons. Denmark ...... 271' Prussia 9,034 Hamburg 8,413 Holland 1,259 f Belgium 240 Other Parts 302 J Computed real value. £470,195. Eolled, but not otherwise manufactured. Denmark Prussia - Belgium Other Parts - 19,519 Tods. 47 T 304 1 3,818 f 37j 4,206 Computed real v.iluo. £128,738. THE EISTD. ULSa U BR ARY. -=»-«- ^ ^$i. nr