LIBRARY 
 
 OF THK 
 
 UNIVERSITY OF CALIFORNIA 
 
 GIFT OF 
 
 PROF. 
 
 Class 
 
DICTIONARY OF CHEMISTBY. 
 
 VOL. L 
 
LONDON 
 
 PRINTED BY S r O T T I 8 W O O D E AND I! O 
 NEW-STREET 6QUAIIH 
 
A DICTIONARY 
 
 OF 
 
 CHEMISTEY 
 
 AND THE 
 
 ALLIED BRANCHES OF OTHER SCIENCES, 
 
 BY 
 
 HENRY WATTS, B. A., F. C. S. 
 
 EDITOR OP 
 'THE JOURNAL OF THE CHEMICAL SOCIETY.' 
 
 ASSISTED BY EMINENT CONTRIBUTORS. 
 
 IN FIVE VOLUMES. 
 
 VOL. I. 
 
 ABICHITE CONGLOMERATE. 
 
 LONDON: 
 
 LONGMANS, GEEEN, AND CO. 
 1866. 
 
Wf 
 
 V/, I 
 
PREFACE. 
 
 THIS WORK was originally intended as a New Edition of URE'S 
 Dictionary of Chemistry and Mineralogy ; but the great changes made 
 in chemical science since the publication of the last edition of that Dictionary 
 (1831) changes, not merely consisting in the addition of new discoveries, 
 but involving a complete revolution in the mode of viewing and 
 expressing chemical reactions have rendered it almost impossible to adapt 
 any matter written so long ago to the existing requirements of the science. 
 The present must therefore be regarded as essentially a new work, in 
 which only a few articles of URE'S Dictionary are retained, chiefly of a 
 descriptive character. In compiling it, the Editor has freely availed 
 himself of the stores of information in GMELIN'S " Handbook," GERHARDT'S 
 " Chimie Organique," ROSE'S " Traite" d' Analyse Chimique," DANA'S 
 " Mineralogy," RAMMELSBERG'S " Mineralchemie," the " Handworterbuch 
 der Chemie," &c. ; and has endeavoured, by careful consultation of original 
 memoirs, to bring the treatment of each subject down to the present time. 
 He has also been fortunate in obtaining the co-operation of several 
 chemists of acknowledged ability and eminence, who have kindly con- 
 tributed articles on subjects to which they have paid special attention: 
 a List of their names is given on the next leaf. 
 
 The work is essentially a Dictionary of Scientific Chemistry, and is 
 intended as a Companion to the New Edition of URE'S Dictionary of Arts, 
 Manufactures, and Mines, to which therefore reference is, for the most 
 part, made for the details of manufacturing operations ; but those branches 
 of chemical manufacture which have come into existence, or have received 
 important developements, since the publication of that work, are described 
 in this Dictionary as fully as its limits will allow, and in all cases ex- 
 planations are given of the principles on which manufacturing processes 
 are conducted, and the chemical changes which they involve. Particular 
 
 237603 
 
vi PREFACE. 
 
 attention has also been given to the description of processes of Analysis, 
 both qualitative and quantitative. 
 
 In order that the work may, as far as possible, truly represent the 
 present state of scientific chemistry, it has been found absolutely necessary 
 to make the modern or " unitary " scale of atomic weights the basis of the 
 system of notation and mode of exposition adopted. Especial care has, 
 however, been taken that the treatment of all Articles which are likely to 
 be consulted, for the sake of practical information, by manufacturers, or 
 others not exclusively occupied in chemical pursuits, shall be such as to 
 make them readily intelligible to all who possess a general knowledge 
 of chemistry, though they may not have followed closely the recent 
 developements of the theoretical parts of the science. Hence, in all such 
 Articles (as ACETIC ACID, ANTIMONY, COPPER, &c.) the formulae are given 
 according to the old notation (printed for distinction, in Italics), as well as 
 according to that adopted in the rest of the work. 
 
 Temperatures are given on the centigrade scale, excepting when the 
 contrary is expressly stated. 
 
 HENRY WATTS. 
 
 7 PROVOST ROAD, LONDON, N.W. 
 July 1863. 
 
LIST OE CONTRIBUTORS. 
 
 EDMUND ATKINSON, Ph.D. F.C.S. 
 
 Professor of Chemistry at the Royal Military College, Sandhurst. 
 
 FRANCIS T. CONINGTON, M.A.. F.C.S. 
 
 Fellow of Corpus Christi College, Oxford, and late Examiner in Natural Science at that 
 University; Author of a < Handbook of Chemical Analysis.' 
 
 WILLIAM DITTMAE, Esq. 
 
 Principal Assistant in the Chemical Laboratory of the University of Edinburgh. 
 
 GEORGE C. FOSTER, B.A. F.C.S. 
 
 Lecturer on Natural Philosophy at the Andersonian University, Glasgow. 
 
 EDWARD FRANKLAND, Ph.D. F.R.S. 
 
 Foreign Secretary of the Chemical Society, and Professor of Chemistry at the Royal Institution 
 of Great Britain. 
 
 FREDERICK GUTHRIE, Ph.D. F.C.S. 
 
 Professor of Chemistry at the Royal College, Mauritius. 
 
 A. W. HOFMANN, LL.D. F.K.S. V.P.C.S. 
 
 Professor of Chemistry at the Government School of Mines. 
 
 WILLIAM S. JEVONS, M.A. 
 
 (lately) Gold Assayer in the Sydney Royal Mint. 
 
 CHARLES E. LONG, Esq. F.C.S. (the late) 
 Analytical Chemist. 
 
 WILLIAM ODLING, M.B. F.R.S. 
 
 Secretary to the Chemical Society, and Professor of Chemistry at St. Bartholomew's Hospital ; 
 Author of a ' Manual of Chemistry.' 
 
 BENJAMIN H. PAUL, Ph.D. F.C.S. 
 
 Consulting Chemist. 
 
 HENRY E. ROSCOE, Ph.D. F.C.S. 
 
 Professor of Chemistry at Owens College, Manchester 
 
 WILLIAM J. RUSSELL, Ph.D. F.C.S. 
 
 Of University College, London. 
 
 ALEXANDER W. WILLIAMSON, Ph.D. F.R.S. Pres. C.S. 
 
 Professor of Chemistry at University College, London, and Examiner in Chemistry at the 
 University of London. (A. W. W.) 
 
 ARTHUR WINCKLER WILLS, Esq. 
 
 Analytical and Manufacturing Chemist, Wolverhampton. (W. W.) 
 
 *#* Articles communicated by the several contributors are signed with their 
 initials j articles taken from UEE'S Dictionary of Chemistry (fourth edition, 1831) are 
 signed with the letter U ; those which have no signature are by the Editor. 
 
DICTIONARY OF CHEMISTRY. 
 
 ABXCHITZ:. (Aphanesite, Strahlerz, Strahlenkupfer.) A native arsenate of 
 copper, found chiefly associated with other copper ores and veins in Cornwall, and 
 in the Hartz. The crystals belong to the monoclinic or oblique prismatic system, 
 but they seldom exhibit any definite shape, being aggregated in radiating groups, 
 or disposed, as extremely minute individuals, in cavities of quartz. Sp. gr. 4 - 2 
 to 4-4. Hardness, 2'5 to 3. Translucent or opaque, with vitreous lustre. Colour, 
 blackish green inclining to blue. Streak, bluish-green. Dana (Mineralogy, ii. p. 428) 
 gives for this mineral the formula SCuO.AsO* + 3CuO.HO*, or AsCu 3 4 + Cu 3 HO, 
 deduced from the analyses of Eammelsberg andDamour. L. Gmelin (Handb. v. 471) 
 
 fives the formula dCuO.AsO 5 + 5fIO, deduced from the analysis of Chenevix, who 
 rand 54 per cent, of protoxide of copper, 30 per cent, of anhydrous arsenic acid, and 
 16 per cent, of water. 
 
 AEIETIC ACID, C 20 H 30 ? When Strasburg or Canadian turpentine (ob- 
 tained respectively from Abies picca and Abies balsamea,} is distilled with water; the 
 residue exhausted with absolute alcohol ; the solution evaporated to dryness ; the re- 
 sidual resin boiled with twice its weight of solution of carbonate of potassium ; the 
 alkaline liquid poured off; and the residue, which is a mixture of abietin and abietate 
 of potassium, treated with 30 times its weight of water, abietin separates in 
 the crystalline form, while abietate of potassium remains in solution. This solution 
 may be decomposed by sulphuric or hydrochloric acid, and the precipitated abietic 
 acid purified by digestion in hot aqueous ammonia. As thus obtained, it is a resinous 
 mass which dissolves easily in alcohol, ether and volatile oils, forming acid solutions, 
 from which it separates in the crystalline state. At 55 it becomes soft and trans- 
 lucent. Its barium-salt is said to contain 191 parts of the acid to 76'6 parts (1 at.) 
 of baryta. The acid is perhaps identical with sylvic or pymaric acid. (Caillot, 
 J. Pharm. xvi. 436; Gerh. iii. 656.) 
 
 ABXETSivr. Prepared as above. It is a tasteless inodorous resin, insoluble in 
 water, soluble in alcohol, especially at the boiling heat, also in ether, rock-oil, and 
 strong acetic acid, and separates in the crystalline form from these solutions by evapo- 
 ration. It melts when heated, and solidifies in a crystalline mass on cooling. It is 
 not acted upon by caustic potash. (Caillot.) 
 
 ABRAZXTS. ( Gismondin.) A mineral of the zeolite family, containing, according 
 to Marignac's analysis : 
 
 8(CaKO.Si0 2 ) + 4Al-'0 3 .Si0 2 -f 18ITO ; [Si = 28 ; = 16]. 
 
 or 2(CaO.KO},Si0 3 + 2(Al s O 3 .SiO 3 )^-9HO; [#-21 ; = 8]. 
 
 It is found on Vesuvius, at Aci-Castello in Sicily, and at Capo di Bove, near Home. 
 It occurs united with Phillipsite in quadratic octahedrons, generally aggregated in 
 
 * The atomic weights adopted in this work are those of the unitary system (II 1 ; O = 1G ; S = 32 ; 
 C = 12). Frequently, however, the formulas of compounds will likewise be given according to the 
 dualistic system (0= 8, S= 16, C = 6) ; and for distinction, these Utter formulas will be printed in 
 italics. 
 
 VOL. I. B 
 
: , JlBSINTHIN ACEDIAMINE. 
 
 masses. Transparent or translucent, with greyish-white colour. Hardness = 4'5. 
 Sp. gr. = 2'265. Gives off one-third of its water at 100. Easily dissolves in acids 
 and gelatinises. It was formerly supposed to be a variety of Phillipsite or lime- 
 harmotome ; but it differs from harmotome in composition as well as in crystalline form, 
 the latter mineral crystallising in the dimetric system. (Dana, ii. 322.) 
 
 ABSIKTTHIW. C 16 H 22 5 . The bitter principle of wormwood (Artemisia absin- 
 thium). It is prepared in the pure state, according to Luck, by exhausting the leaves 
 of wormwood with alcohol, evaporating the extract to the consistence of a syrup ; 
 and agitating with ether. This ethereal solution is evaporated to dryness, and the 
 residue treated with water containing a little ammonia, which dissolves the resin, and 
 leaves the absinthin nearly pure. To complete the purification, it is digested with 
 weak hydrochloric acid, washed with water, dissolved in alcohol, and treated with 
 acetate of lead, as long as a precipitate is formed. After the removal of this precipi- 
 tate by filtration, the excess of lead is precipitated by sulphuretted hydrogen, and the 
 eolution is evaporated. The absinthin then remains as a hard, confusedly crystalline 
 mass, possessing an extremely bitter taste. It is but slightly soluble in water, very 
 soluble in alcohol, and less so in ether. It possesses distinctly acid characters, and 
 is dissolved by potash and ammonia. (Me in, Ann. Ch. Pharm. viii. 61 ; Luck, ibid. 
 Ixxviii. 87; Gerh. iv. 258.) 
 
 ABSORPTION OF GASES. See GASES. 
 
 AC ACIST, or AC ACI A-G-ITIWC. Known in commerce as gum-arabic. See ARABIN 
 and GTJM. 
 
 ACAXtXOXtXTE. A variety of chabasite from New Caledonia, distinguished by 
 its large amount of alkali. (Hayes, Sill. Am. J. [2] I. 122.) 
 
 ACAJOU. The stem of the Acajou or Cashew-nut tree, Anacardium occidental, 
 yields a yellow gummy substance, sparingly soluble in water, which is a mixture of 
 ordinary gum and bassorin. The pericarp of the nuts of the same tree contains a 
 large quantity of a red-brown resinous substance, which produces inflammation and 
 blistering of the skin. It may be extracted by ether, and the ethereal solution when 
 slowly evaporated, leaves a residue consisting of a network of small crystals of ana- 
 cardie acid, soaked in an oily liquid called cardol, to which the resin owes its acrid pro- 
 perties (Stadeler, Ann. Ch. Pharm. Ixiii. 137). The name acajou is also applied 
 to a gum and resin obtained from the stem of the mahogany-tree. The gum re- 
 sembles that of the cherry-tree. 
 
 ACAROXD RESIN*. The resin of XanthorrJica hastilis, a liliaceous tree grow- 
 ing in New Holland ; also called resin of Botany Bay. It has a yellow colour, an agree- 
 able odour, and is soluble in alcohol, ether, and caustic potash. Its potash-solution 
 treated with hydrochloric acid deposits benzoic and cinnamic acids. Nitric acid con- 
 verts it into picric acid, and so readily, that this resin appears to be the best raw material 
 for obtaining picric acid. By distillation, the resin yields a light neutral oil, which ap- 
 pears to be a mixture of benzol and cinnamol, and a heavy acid oil, consisting of hydrate 
 of phenyl, mixed with small quantities of benzoic and cinnamic acids. (Stenhouse, 
 Ann. Ch. Pharm. Ivii. 84.) 
 
 ACECHLORIDE OP PLATINUM. See ACETONE, Decompositions (p. 29). 
 
 ACEiDIAIVlINE. C 2 H 6 N 2 . When hydrochlorate of acetamide is heated in a sealed 
 tube to 180 200, and the product afterwards distilled, or when acetamide is dis- 
 tilled in a stream of dry hydrochloric acid gas, several volatile products pass over, and 
 a residue is left consisting of hydrochlorate of acediamine, mixed with sal-ammoniac. 
 (See ACETAMIDE) : 
 
 2C 2 H 5 NO + HC1 = C^^ 2 . HC1 + C 2 H 4 2 . 
 
 Acetaraide. Hydrochlorate Acetic acid, 
 
 of acediamine. 
 
 Alcohol extracts the hydrochlorate of acediamine from this residue, and deposits it 
 by spontaneous evaporation in prismatic crystals, which may be completely freed from 
 adhering sal-ammoniac by solution in a mixture of alcohol and ether, and evaporation 
 in vacuo. The hydrochlorate decomposed by sulphate of silver, yields the sulphate of 
 acediamine (C 2 HN 3 ) 2 . S0 4 H 2 , which crystallises in colourless nacreous laminae, easily 
 soluble in water. The aqueous solution of the hydrochlorate mixed with dichloride of 
 platinum yields the chloroplatinate of acediamine, C 2 H 6 N 2 . HC1. PtCl 2 , in rather large, 
 bard, yellowish red prisms. 
 
 Acediamine is very unstable, and cannot be obtained in the free state. When the 
 sulphate or hydrochlorate is heated with potash or baryta, ammonia is given off, and 
 an acetate of the alkali is produced : 
 
 C 2 H 6 N 2 + 2H 2 = C 2 H 4 2 + 2NH. 
 
ACETAL. 3 
 
 Acediamine may be regarded as ammonia in which 1 at. H is replaced by the mona- 
 tomic radical C 2 H 4 N (azethyl), its rational formula being then N.H 2 . C 2 H 4 N or as a 
 double molecule of ammonia, N 2 H 6 , having 3 at. H replaced by the triatomic radical 
 C 2 H S , making its formula N 2 .H 3 . (C 2 !! 3 )"' It bears the same relation to acetamide as 
 ethylamine to alcohol : 
 
 C 2 H0 + NH 3 = C 2 H 7 N + H 2 : and C 2 H S NO + NH 3 = C 2 H 6 N 2 + H 2 0. 
 
 (Strecker, Ann. Pharm. ciii. 328.) 
 
 AC23PHOSGEWTZC ACXX and ACEPHOSSIC ACID. Compounds produced 
 by the action of phosphorus on acetone (see page 28). 
 
 ACETAX.. C 6 H U 2 . [G-m. ix. 38 ; Gerh. ii. 268;] A product of the oxidation 
 of alcohol, first observed by Dobereiner, more fully examined by Liebig (Ann. Ch. 
 Pharm. v. 25; xiv. 156), still further by Stas (Ann. Ch. Phys. [3] xix. 146), who 
 first correctly determined its empirical formula, and finally by Wurtz (Compt. rend. 
 xlviii. 478 ; Ann. Ch. Phys. [3] xlviii. 370 ; Ann. Ch. Pharm. cviii. 84). It is also 
 obtained from aldehyde. ("Wurtz andFrapolli, Ann. Ch. Pharm. cvii. 228.) 
 
 Preparation. I. From Alcohol. 1. By the imperfect oxidation of alcohol, under 
 the influence of platinum-black. Pieces of pumice-stone previously washed and 
 ignited are moistened with nearly absolute alcohol, and placed at the bottom of a 
 large wide-necked flask, which is then filled up with capsules containing platinum- 
 black, covered with a glass plate, and exposed to a temperature of 20, tiU the whole 
 of the alcohol is acidified. Alcohol of 60 per cent, is then poured into the flask, in 
 quantity not quite sufficient to cover the pumice-stones, and the flask left to itself for 
 two or three weeks in a room at a temperature of 20, the glass plate being removed 
 from time to time to admit fresh air. The thickish liquid is then drawn off, and the 
 same process repeated with fresh alcohol, till several quarts of thickish acid liquid are 
 obtained. This liquid is neutralised with carbonate of potassium, saturated with 
 chloride of calcium and distilled, and the first fourth of the distillate is saturated with 
 fused chloride of calcium, which separates from it a mixture of alcohol, acetic-ether, 
 aldehyde, and acetal. The aldehyde is removed by distillation over the water-bath ; 
 the residue treated with strong potash to decompose the acetic ether; the alcohol 
 removed by washing with water ; and the remaining liquid, the acetal, dried over 
 chloride of calcium and rectified. (Stas.) 
 
 2. By distilling alcohol with dilute sulphuric acid and peroxide of manganese. A 
 mixture of 2 parts alcohol, 3 parts peroxide of manganese, 3 parts sulphuric acid, and 
 
 2 parts water (the proportions given by Liebig for the preparation of aldehyde), 
 is subjected to distillation as soon as the frothing which first ensues has ceased ; 
 
 3 parts of liquid are distilled off; the distillate is rectified ; and the portion which 
 goes over at 80 is collected apart from that which distils between 80 and 95. 
 The first portion is mixed with chloride of calcium and rectified, the distillate 
 obtained below 60 chiefly consisting of aldehyde, while above 60 a product is 
 obtained, which, when treated with a strong solution of chloride of calcium, yields 
 an ethereal liquid. The portion of the former liquid which came over between 80 
 and 95, is also rectified, and the first portion of the resulting distillate treated with 
 strong solution of chloride of calcium, whereupon it likewise yields an ethereal liquid. 
 These ethereal liquids, containing aldehyde, acetic ether, &c. and acetal are united, 
 and shaken with caustic potash to resinise the aldehyde and decompose the acetic 
 ether. The brown liquid which floats upon the potash-solution is separated and 
 distilled ; the distillate again mixed with chloride of calcium ; the liquid thus separated 
 is heated to 100 for twenty-four hours with twice its volume of caustic potash in a 
 sealed tube ; the lower stratum is rectified ; the distillate again shaken with chloride of 
 calcium ; and the separated liquid is digested with pulverised chloride of calcium, and 
 submitted to simple rectification. Pure acetal then distils over from 100 to 105. 
 (Wurtz.) 
 
 3. By the action of chlorine upon alcohol, acetal being indeed the principal pro- 
 duct of that reaction, so long as no substitution-products are formed : 
 
 3C 2 H 6 + 2C1 = C 6 H 14 2 + 2HC1 + H 2 0. 
 
 Chlorine is passed through 80 per cent, alcohol cooled to between 10 and 15, till 
 a portion becomes turbid on the addition of water, indicating the formation of substi- 
 tution-products. One fourth of the strongly acid liquid is then distilled off; the dis- 
 tillate neutralised with chalk ; one fourth again distilled off; and the distillate, con- 
 sisting of alcohol, acetic ether, aldehyde and acetal, treated as above to separate the 
 acetal. (Stas.) 
 
 According to Lieben (Ann. Ch. Phys. [3] lii. 313), the chief products of the action 
 of chlorine on alcohol of 80 per cent, are monochloracctal and dichloracetal. (p. 5.) 
 
 II. From Aldehyde. 1. 15v treating aldehyde with pentabromide of phosphorus, 
 
 n 2 
 
4 ACETAL. 
 
 whereby it is converted into bromide of ethylidene C 2 H 4 Br 2 (a compound isomeric with 
 bromide of ethylene), and acting on this compound with ethylate of sodium. 
 C 2 H 4 Br 2 + 2C 2 H 5 NaO = 2NaBr + 2C 6 H 14 2 . 
 
 This mode of preparation is, however, very troublesome, on account of the difficulty 
 of obtaining the bromide of ethylidene. Chloride of ethylidene C 2 H 4 C1 2 , (produced by 
 the action of pentachloride of phosphorus on aldehyde) does not appear to yield acetal 
 when treated with ethylate of sodium. 
 
 2. By passing hydrochloric acid gas into a mixture of 1 vol. aldehyde and 2 vols. 
 absolute alcohol immersed in a freezing mixture, whereby the compound C 4 H 9 C10 is 
 obtained in the form of an ethereal liquid floating on aqueous hydrochloric acid, 
 and treating this compound with ethylate of sodium : 
 
 C 2 H 4 + C 8 H 6 + HC1 = C 4 H 9 C10 + H 2 
 and C 4 H 9 C10 + C 2 H 8 NaO = NaCl + C 6 H U 2 
 
 (Wurtz and Frapolli, Compt. rend, xlvii. 418 ; Ann. Ch. Pharm. cviii. 223.) 
 
 Properties. Pure acetal is a colourless liquid, less mobile than ether, having a pecu- 
 
 liar agreeable odour and a refreshing taste, with an after-taste like that of hazel nuts. 
 
 Sp. gr. 0-821 at 22-4. Boils at about 105 C., with the barometer at 0768 met. 
 
 Vapour density = 4'141. 
 
 It dissolves in eighteen times its volume of water at ordinary temperatures, the 
 
 solubility increasing as the temperature rises. From the aqueous solution it is sepa- 
 
 rated by chloride of calcium and other soluble salts. Ether and alcohol dissolve it in 
 
 all proportions. 
 
 Decompositions. 1. Acetal is not altered by mere exposure to the air, but in contact 
 
 with platinum-black it is quickly converted, first into aldehyde, and then into acetic 
 
 acid: 
 
 C 6 H 14 0* + 20 = 3C 2 H 4 + H 2 0. 
 
 Acetal. Aldehyde. 
 
 It is likewise oxidised by nitric and by chromic acid. 2. Caustic alkalies do not decom- 
 pose it, if the air is excluded. 3. Chlorine abstracts hydrogen from it and forms sub- 
 stitution-products. 4. Strong sulphuric acid dissolves and then decomposes it, the 
 mixture turning black. 5. Hydrochloric acid likewise dissolves and blackens it, form- 
 ing choride of ethyl. 6. Pentachloride of phosphorus acts strongly upon it, forming a 
 large quantity of chloride of ethyl, together with other products. 7. Heated in a sealed 
 tube with several times its weight of glacial acetic acid, it yields acetic ether, more than 
 1 atom of that compound being formed from 1 atom of acetal. 
 
 These reactions tend to show that acetal is an ethyl-compound. Stas regarded it 
 as a compound of 1 at. aldehyde with 1 at. ether : 
 
 C 2 H 4 + C 4 H 10 = C a H 14 2 ; 
 
 and "Wurtz, in his earlier researches on glycol (Compt. rend, xliii. 478), regarded it as 
 glycol TT 2 [ 2 > i 11 which 2 at. hydrogen are replaced by ethyl, ^-rp^ I O 2 . This view 
 
 of its constitution was corroborated by the result of distilling a mixture of alcohol and 
 wood-spirit with sulphuric acid and peroxide of manganese, whereby a distillate was 
 
 /"12TT4 \ 
 
 obtained consisting of dimethylate of ethylene /nrpmf O 2 , and methylethylate of ethy- 
 
 lene PUT-, /loirs f 0*- Subsequent researches have however shown that acetal is not 
 L>J B .Lrl ) 
 
 identical, but only isomeric with diethyl-glycol, or diethylate of ethylene C 2 !! 4 . (C 2 H 5 ) 2 . 2 . 
 For, when glycol C 2 H 4 .H 2 .0 2 is treated with sodium, 1 at. hydrogen is eliminated, and 
 the compound C 2 H 4 . NaH.O 2 is obtained. This compound treated with iodide of ethyl 
 yields ethylate of ethylene C 2 H 4 . C 2 H 5 . H.O 3 , whence, by the action of potassium, the 
 compound C 2 H 4 . C 2 H 5 . K.O 2 is produced ; and, lastly, this compound treated with 
 iodide of ethyl yields diethylate of ethylene C 2 H 4 . (C 2 H 5 ) 2 . O 2 . Now this liquid has a 
 specific gravity of 0'7993 at C., and boils at 123-5 C., whereas acetal has a sp. gr. 
 of 0-821 at 22-4, and boils at 105, that is to say, 18'5 lower. Eecent experiments 
 byBeilstein (Ann. Ch. Pharm. cxii. 240) seem to indicate that the rational formula 
 of acetal is C 4 H 9 O.C 2 H 5 .O. 
 
 Chloracetals (A.Lieben,Ann.Ch. Phys. [3]lvi. 313). Three of these compounds 
 have been obtained ; viz. mono-, di-, and tri-chloracctal. The two former are produced 
 by the action of chlorine on alcohol of ordinary strength (80 per cent.) When the 
 chlorine has been passed through for some time, and the heavy oil which separates on 
 addition of water is washed several times with aqueous chloride of calcium, and sub- 
 mitted to fractional distillation, it begins to boil at 80, and the boiling point gradually 
 
ACETAMIDE. 5 
 
 rises to 200, not, however, remaining stationary at any intermediate point. The por- 
 tion which distils below 120 consists of aldehyde and compound ethers; that which 
 distils above 120 (which is the larger portion) contains monochloracetal and dichlor- 
 acetal. On again submitting it to fractional distillation, the greater part goes over 
 between 170 and 185; this portion consists chiefly of diehloracetal, which may be 
 obtained pure by subsequent rectification. To separate the monochloracetal, the por- 
 tion of the second distillate boiling below 170, and the portion of the first distillate 
 which passed over above 120, are heated for several days with aqueous potash, 
 whereby a watery liquid is obtained, containing chloride and formate of potassium, 
 and an oily liquid consisting chiefly of monochloracetal mixed with dichloracetal ; these 
 compounds are finally separated by fractional distillation. 
 
 According to Lieben, the product of the action of chlorine on alcohol of ordinary 
 strength does not contain acetal. This is contrary to the statement of Stas, who, in 
 fact, prepared acetal by this very process. Probably the relative quantities of acetal, 
 monochloracetal, and dichloracetal obtained depend on the duration of the action of the 
 chlorine (compare page 3). 
 
 Monochloracetal, C 6 H 13 C10 2 , is a colourless liquid, having an ethereal aromatic odour, 
 and boiling at about 155. Vapour-density, by experiment 5'38 ; by calculation (2 vols.) 
 5'29. It is perfectly neutral, insoluble in water, soluble in alcohol. It is not attacked 
 by aqueous potash, and does not precipitate nitrate of silver. 
 
 Dichloracetal, C 6 H 12 CP0 2 , is a colourless neutral aromatic liquid of sp. gr. 1-1383 at 
 14. Boils at about 180. Vapour-density, by experiment 6-45 ; by calculation 
 (2 vols.) 6-435. (Lieben.) 
 
 Trichloracetal, C (i H u Cl 3 2 , is produced, together with dichloracetal, by the action of 
 chlorine on highly concentrated but not absolute alcohol. (Dumas, Lieben.) 
 
 AC EXAMINE. C 2 H 5 NO = KH 2 .C 2 H 3 0. Produced : _ 
 
 1. By heating acetate of ethyl with strong aqueous ammonia to about 120 : 
 
 C 2 H 3 O.C 2 H 5 .0 + NH 3 = NH 2 .C 2 H 3 + C 2 H 5 .H.O 
 
 Acetate of ethyl. Acetamide. Alcohol. 
 
 2. By the action of ammonia on acetic anhydride : 
 
 (C 2 H 3 0) 2 + NH 3 = NH 2 .C 2 H 3 + C 2 H 3 O.H.O 
 
 Acetic Acetamide. Acetic acid, 
 
 anhydride. 
 
 3. By distilling acetate of ammonium (C 2 H 4 0'.NH 3 = C 2 H 5 NO + H 2 0). A large 
 quantity of ammonia is given off at first, then at 160 an acid distillate, consisting 
 chiefly of acid acetate of ammonium ; above 1 60, a distillate containing acetamide 
 which crystallises in the condensing tube; and above 190 nearly pure acetamide. 
 By saturating glacial acetic acid with dry ammoniacal gas, and then distilling, \ of the 
 acetic acid may be converted into acetamide. (Kundig, Ann. Ch. Pharm. cv. 277.) 
 
 Acetamide is a white crystalline solid, which melts at 78 and boils at 221 or 222. 
 It deliquesces when exposed to the air, and dissolves readily in water. Heated either 
 with acids or with alkalis, it takes up water, and is converted into acetic acid and 
 ammonia. Distilled with phosphoric anhydride, it gives up water and is converted 
 into acetonitrile or cyanide of methyl C 2 H 3 N. Heated in a stream of dry hydrochloric 
 acid gas, it yields a liquid and a crystalline distillate, and a brownish non-volatile 
 residue. The liqiiid portion of the distillate consists of strong acetic acid, together 
 with small quantities of chloride of acetyl, and perhaps acetonitrile. The crystalline 
 distillate is a mixture of hydrochlorate of acetamide, and a compound of acetamide 
 and diacetamide C 2 H 5 NO.C 4 H 7 N0 2 ; the latter compound may be extracted by ether, 
 in which the hydrochlorate of acetamide is insoluble. The non-volatile residue con- 
 sists of hydrochlorate of acediamine mixed with sal-ammoniac. The decomposition is 
 represented by the following equations : 
 
 2C 2 H 5 NO + HC1 = C'H^O 2 + NH'Cl 
 
 Diacetamide. 
 
 2C 2 H 5 NO + HC1 = C 2 H 6 N 2 .HC1 + C 2 H J 2 
 
 Hydrochlorate Acetic 
 
 of acediamine. acid. 
 
 C 2 H 5 NO + 2IIC1 = C 2 H 3 OC1 + NH 4 C1 ; C 2 H 5 NO - H 2 = C 2 H 3 N. 
 
 Chloride of Acetonitrile. 
 
 acetyl. 
 
 Acetamide acts both as a base and as an acid, combining with hydrochloric and with 
 nitric acid, and likewise forming salts in which 1 atom of its hydrogen is replaced by 
 a metal. 
 
 B 3 
 
6 ACETAMIDE. 
 
 Hydrochlorate of Acetamide, (C 2 H 5 NO) 2 .HC1 is prepared : 
 
 1. By mixing acetamide fused 'at a gentle heat with oxy chloride of phosphorus, 
 dissolving the resulting crystalline mass in absolute alcohol, and leaving the solution 
 to cool, or better, mixing it with ether; hydrochlorate of acetamide is then obtained 
 in colourless crystalline needles. The crystalline mass first produced, appears to be 
 a compound of acetamide and oxychloride of phosphorus, and this, on addition of 
 alcohol, yields phosphate of ethyl and hydrochloric acid, which unites with the 
 acetamide : 
 
 2C 2 H 5 NO + POC1 8 + 3(C 2 H 5 .H.O) = (C 2 H 5 NO) 2 .HC1 + P(C 2 H 5 ) 3 0* + 2HCL 
 
 2. By directing a stream of dry hydrochloric acid gas on a solution of acetamide in 
 alcohol and ether cooled from without, washing the resulting crystalline mass with 
 anhydrous ether, and dissolving it in warm alcohol. The solution on cooling, or more 
 quickly on addition of ether, deposits the hydrochlorate in crystals. This mode of 
 preparation is preferable to the former. The compound forms long spear-shaped crystals, 
 having an acid taste and reaction, easily soluble in water and alcohol, but insoluble in 
 ether. Heated in a sealed tube to between 180 and 200, it decomposes, yielding 
 the same compounds that are obtained by heating acetamide in dry hydrochloric acid 
 gas. (Strecker, Ann. Ch. Pharm. ciii. 321.) 
 
 Nitrate of Acetamide, C 2 H 5 NO.N0 3 H, is obtained by dissolving acetamide in cold 
 strong nitric acid. It forms colourless acid crystals, which melt at a moderate heat, 
 and detonate at a higher temperature, leaving scarcely any residue. 
 
 CHLORACETAMIDES. Monochloracetamide, C 2 H 4 C1.NO = N.1I 2 .C 2 H 2 C10, is 
 obtained : 
 
 1. By the action of ammonia on monochloracetate of ethyl: 
 
 C 2 H 2 C10.C 2 IP.O -H NH 3 = N.H 2 .C 2 H 2 C10 + C 2 H 6 0. 
 
 2. By bringing perfectly dry ammoniacal gas in contact with chloride of mono 
 chloracetyl : 
 
 C 2 H 2 C10.C1 + 2NH 3 = KH 2 .C 2 H 2 C10 + NH 4 C1. 
 
 The product is a white amorphous mass, from which absolute alcohol extracts the 
 amide, and deposits it in large shining laminae. The amide dissolves in 10 parts of 
 water and 10| parts of alcohol at 24, but is very sparingly soluble in ether. It is 
 decomposed by potash, yielding chloride and acetate of potassium. (E. Willm. Ann. 
 Ch. Phys. [3] xlix. 99.) 
 
 Trichloracetamide. C 2 H 2 C1 3 NO = KH 2 .C 2 C1 3 0. This compound is produced 
 by the action of gaseous or aqueous ammonia : 
 
 1. On chloride of trichloracetyl : 
 
 C 2 CPO.C1 + 2NH 3 = N.H 2 .C 2 C10 + NH 4 C1. 
 
 2. On trichloracetate of ethyl : 
 
 C 2 C1 S O.C 2 H 5 .0 + NH 3 = N.H 2 .C 2 C1 3 + C 2 H 8 0. 
 
 3. On chloraldehyde, C 2 C1 4 0, or the polymeric compound, perchlorucetic ether, 
 C 4 C1 8 2 : 
 
 CTC1 4 + 2 NIP = C 2 H 2 CPNO + NIPC1. 
 
 Also by the action of ammonia on the perchlorinated ethylic ethers of formic, carbonic, 
 oxalic, and succinic acids, all these compounds yielding chloraldehyde when heated. 
 The best product is obtained from perchloracetic ether. The mass is treated 
 with cold water to dissolve the sal-ammoniac, and the resid.ua! trichloracetamide is 
 crystallised from ether. It then forms snow-white crystalline laminae. It dissolves 
 also in boiling water and in alcohol, and crystallises from the aqueous solution in ta- 
 bular crystals belonging to the rhombic system. It has a sweetish taste ; melts at 
 135, begins to turn brown at 200, and boils at about 240. It gives off ammonia when 
 heated with potash. Ammonia dissolves it after a while, and the solution yields, by 
 evaporation, beautiful prisms of trichloracetate of ammonium. Anhydrous phos- 
 phoric acid converts it into chloracetonitrile or cyanide of trichloromethyl : C 2 H r 'CPNO 
 -H 2 = C 2 C1*N. (Cloez, Ann. Ch. Phys. [3] xvii. 305; Malaguti, ibid. xvi. 5 ; 
 Cahours, ibid. xix. 352; G-erhardt, Compt. chim. 1848, 277; Traite, i. 760; 
 Gm. ix. 270.) 
 
 Tetrachlor acetamide, C 2 HC1'NO^N.H.C1.C 2 CFO; sometimes called chlora- 
 cetamic acid, is formed by exposing trichloracetamide, slightly moistened with water, to 
 the action of chorine in sunshine. It then sublimes in needles, which may be purified by 
 crystallisation from ether. It is permanent in the air, melts when heated, and partly 
 sublimes undecomposed. It is nearly inodorous, but has a harsh disagreeable taste. 
 Insoluble in water, but dissolves pretty readily in alcohol and wood-spirit, and very 
 easily in ether. It dissolves without decomposition in cold aqueous alkalis, forming 
 
ACETIC ACID. 7 
 
 crystallisable salts. When boiled with potash, it gives off ammonia, and leaves chlo- 
 ride and carbonate of potassium : 
 
 C 2 HC1 4 NO + 3H 2 = NH 3 + 4HC1 + 2 CO 2 . 
 (Cloez, Ann. Ch. Phys. [3] xvii. 305.) 
 
 Bromacetamides and lodacetamides are likewise known. 
 
 DIACETAMIDE, C^'NO 2 = NH(C 2 H 3 0) 2 . The ethereal solution of the compound of 
 ncetamide and diacetamide obtained by the action of hydrochloric acid gas on ace- 
 tamide, deposits, when hydrochloric acid gas is passed through it, spicular crystals of 
 hydrochlorate of acetamide, and the liquid filtered therefrom yields by evaporation 
 over sulphuric acid, crystals of diacetamide, easily soluble in water, alcohol, and ether. 
 The crystals when boiled with acids are resolved into acetic acid and ammonia, but 
 not so readily as acetamide. The alcoholic solution boiled with dichloride of platinum 
 deposits chloroplatinate of ammonium. (Strecker.) 
 
 ETHYLACETAMIDE. See ETHYLAMINE. 
 
 MERCTJRACETAMIDE, C 2 H 4 HgNO. An aqueous solution of acetamide saturated 
 with mercuric oxide deposits by evaporation in vacuo, colourless crystalline crusts 
 sparingly soluble in alcohol. Silver-acetamide, C 2 H 4 AgNO, is obtained in a similar 
 manner in crystalline scales. 
 
 PHENYLACETAMIDE, or ACETANILIDE, see PHENYLAMINE. 
 
 ACETEIffE. Synonyme of ETHYLENE and OLEFIANT GAS. 
 
 ACETIC ACID. Essigsaure, Acide Acetigue. C 2 H 4 2 = C "^. <0 | 0, or C 2 H 3 2 .H. 
 
 The hydrate or hydrated oxide of acetyl ; it may be regarded as a molecule of water 
 (IPO), in which half the hydrogen is replaced by acetyl C 2 H 3 0. (It was formerly 
 supposed to be derived from a radicle, C*H 3 , also called acetyl, which, in combination 
 with 3 atoms of oxygen, formed anhydrous acetic acid C^H^O 3 ; and this in com- 
 bination with an atom of water 210, formed hydrated acetic acid, C 4 H S O 3 .HO = 
 6'W 4 6> 4 ] See ACETYL. 
 
 Sources. Acetic acid exists, in nature, in the organic kingdom only, being found 
 in the juices of many plants, especially of trees, and existing probably also in several 
 of the animal secretions ; but more commonly it results from the decomposition and 
 oxidation of organic bodies. 
 
 Formation. 1. By the destructive distillation of organic substances, especially of 
 wood.. 2. By the action of oxidising agents, viz. atmospheric oxygen, chromic acid 
 nitric acid, hypochlorous acid, &c., on alcohol and other organic bodies. 3. By the 
 action of hydrate of potassium or hydrate of sodium at a high temperature on various 
 organic bodies, e.g. succinic acid, oleic acid, malic acid, sugar, alcohol, &c. 4. By 
 heating cyanide of methyl with aqueous caustic alkalis : CIF.CN + 2H 2 = C*H 4 2 
 + NH 3 . 5. By the action of carbonic anhydride on sodium-methyl ; CO 2 + CH 3 Na = 
 C'-H 3 Na0 2 (acetate of sodium). 6. By the reducing action of zinc or sodium-amalgam 
 on chloracetic acid. 
 
 Preparation. 1. From alcohol. Alcohol is converted into acetic acid by various 
 processes of oxidation ; e. g. by the action of spongy platinum. If a tray of finely- 
 divided spongy platinum be placed on a triangle over a porcelain dish containing a little 
 alcohol gently warmed, and the whole covered with a bell-glass standing on a wedge, 
 and open at the top so as to allow a gentle current of atmospheric air to pass through 
 the apparatus, the oxidation of the alcohol proceeds rapidly, acetic acid condensing in 
 abundance on the inside of the bell-jar. 
 
 By this process, however, much of the alcohol is converted into aldehyde, and lost 
 by volatilisation. It would appear, in fact, that, in the formation of acetic acid by 
 direct oxidation, aldehyde is always developed as an intermediate product, especially 
 if the oxidising influence be not sufficiently rapid 
 
 C 2 H 6 + = C 2 H 4 + H 2 ; and C^O + = C 2 H 4 2 . 
 
 Alcohol. Aide- Aide- Acetic 
 
 hyde. hyde. acid. 
 
 The oxidation of alcohol by atmospheric oxygen is greatly promoted by the presence 
 of ferments ; and, in fact, in the ordinary processes for making vinegar, an alcoholic 
 solution is exposed to the joint influence of air and a ferment. In France and Ger- 
 many wine is usually employed, and in England malt. 
 
 WINE VINEGAR ( Wdnessig, Finaigre).Tlie following is the plan of making vinegar 
 practised in Paris. The wine destined for vinegar is mixed in a large tun with a 
 quantity of wine-lees, and the whole being transferred into cloth-sacks, placed within 
 a large iron-bound vat, the liquid matter is squeezed through the sacks by superin- 
 cumbent pressure. What passes through is put into large casks set upright and 
 
 B 1 
 
8 ACETIC ACID. 
 
 having a small aperture at the top. In these it is exposed to the heat of the sun in 
 summer, or to that of a stove in winter. Fermentation supervenes in a few days. If 
 the heat should then rise too high, it is lowered by cool air and the addition of fresh 
 wine. In the skilful regulation of the fermentative temperature consists the art of 
 making good wine-vinegar. In summer, the process is generally completed in a 
 fortnight ; in winter, double the time is requisite. The most favourable temperature 
 is between 25 and 30 (77 and 86 F.). The vinegar is then run off into barrels 
 containing several chips of birch wood. In about a fortnight it is found to be 
 clarified, and is then fit for the market. It must be kept in close casks. 
 
 At the same time that the alcohol is thus acidified, the nitrogenous organic matters 
 which have served as ferments have likewise assumed new forms, and settled at the 
 bottom of the vessel in the form of a white gelatinous mass, known as "mother of 
 vinegar." This substance, which has been described by Mulder as a fungoid plant, 
 under the name of Mycoderma Vinl, is a nitrogenised body, which has the power of 
 exciting the acetification of pure alcohol in the presence of atmospheric air, probably 
 in consequence of its own tendency to change. By treating it with potash, the whole 
 of the nitrogen is removed, pure cellulose alone remaining. 
 
 A slight motion is found to favour the formation of vinegar, and to endanger its 
 decomposition after it is made. Chaptal ascribes to agitation the operation of thunder, 
 though it is well known, that when the atmosphere is highly electrified, beer is apt to 
 become suddenly sour, without the concussion of a thunder-storm. Vinegar does not 
 keep well in cellars exposed to the vibrations occasioned by the rattling of carriages. 
 The lees, which had been deposited by means of isinglass during repose, are thus 
 jumbled into the liquor, and promote the fermentation. 
 
 Almost all the vinegar of the north of France being prepared at Orleans, the manu- 
 facture of that place has acquired such celebrity as to render the process worthy of a 
 separate consideration. 
 
 The Orleans casks contain nearly 400 pints of wine. Those which have been 
 already used are preferred. They are placed in three rows, one over another, the upper 
 ones having an aperture of two inches diameter, kept always open. The wine for ace- 
 tification is kept in adjoining casks containing beech shavings, to which the lees 
 adhere. The wine thus clarified is drawn off to make vinegar. One hundred pints of 
 good vinegar, boiling hot, are first poured into each cask, and left there for eight days ; 
 ten pints of wine are mixed in, every eight days, till the vessels are full ; and the 
 vinegar is allowed to remain in this state fifteen days, before it is exposed for sale. 
 The manufacturers at Orleans prefer wine of a year old for making vinegar ; but if 
 the wine has lost its extractive matter by age, it does not readily undergo the acetous 
 fermentation. 
 
 The used casks, called mothers, are never emptied more than half, but are succes- 
 sively filled again, to acetify new portions of wine. In order to judge if the mother 
 works, the vinegar makers plunge a spatula into the liquid; and according to the 
 quantity of froth which the spatula shows, they add more or less wine. In summer, 
 the atmospheric heat is sufficient. In winter, stoves heated to about 76 Fahr. main- 
 tain the requisite temperature in the manufactory. 
 
 Quick method of Vinegar-making (Schnellessigbcreitung'). Since the efficient con- 
 version of the alcohol into acetic acid essentially depends upon the completeness of the 
 oxidation, the German chemists have proposed to promote this result by enlarging 
 the surface of the liquid exposed to the air. This is effected by allowing the alcoholic 
 liquor to trickle down in a fine shower from a colander through a large oaken tube 
 (called the vinegar generator, or graduator), filled with beech chips, up which a cur- 
 rent of air ascends through apertures in the sides. By the oxidation which goes on, 
 the temperature of the liquid rises to 37 or 40 C. (100 or 104 Fahr.). The liquid 
 requires to be passed three or four times through the cask before the acetification is 
 complete, which takes place in twenty-four or thirty-six hours. Care should be taken 
 to allow a sufficient supply of air. 
 
 In England the same result is often attained by causing the alcoholic liquor to be 
 distributed by means of a Barker's mill or other contrivance, over the beech shavings 
 in a tun, whilst a current of air is forced up through it by two floating gasometers 
 which are made to rise and fall alternately by steam power. 
 
 Wine vinegar is of two kinds, white or red, according as it is prepared from white or 
 red wine. It contains, besides acetic acid and water, sugar, colouring matter, gum, and 
 salts, especially bitartrate of potassium. Its specific gravity varies from 1*014 to 1-022. 
 
 MALT VINEGAR. This is prepared from malt or a mixture of malt and raw barley, 
 which is mashed with water as in the ordinary operation of brewing ; the wort is then 
 submitted to the vinous fermentation and the liquor thus obtained is converted by 
 oxidation into vinegar. This effected in two ways ; either by the process of field inq 
 or stoving. 
 
 When fielding, that is, exposure to the open air, is resorted to, the wort must be 
 
ACETIC ACID. 9 
 
 made in the spring months, and then left to finish during several^ months of the 
 warm season. In consequence, therefore, of the length of time required, the latter, 
 or staving process, is more generally used. The wash is introduced into barrels 
 standing endways, tied over with a coarse cloth, and placed close together in darkened 
 chambers, artificially heated by a stove. The liquor remains in these barrels until the 
 acetification is complete. This usually occupies several weeks or months. The product 
 is next introduced into large tuns with false bottoms, on which rape (the residuary 
 fruit from the making of British wines) is placed, and allowed slowly to filter through 
 them. Below the false bottom and above the true one is placed a tap which allows 
 the vinegar to flow into a back or cistern. From this cistern a pump raises the liquid 
 to the top of the vessel, and thence it flows through the rape to be again returned. Or 
 sometimes the rape tuns are worked by pairs, one of them being quite filled with 
 vinegar from the barrels, the other only three parts, so that the acetification is 
 excited more readily in the latter than the former, and every day a portion of the 
 vinegar is conveyed from one to the other, till the whole is finished and fit for sale. 
 
 Malt vinegar has a yellowish red colour, an agreeable acid taste, which is due to 
 acetic acid ; but the aromatic odour which distinguishes both it, and also wine vinegar, 
 from pyroligneous acid (to be afterwards described) is imparted to it by the presence 
 of acetic and other ethers. 
 
 Vinegar of four different strengths is sold by the makers, distinguished as Nos. 18, 
 20, 22, and 24. The last, which is the strongest, and is called proof vinegar, contains 
 6 per cent, of real acetic acid; its specific gravity is 1-019. _ (Pereira.) 
 
 Vinegar is liable to undergo a putrefactive decomposition, which was believed by 
 the makers to be prevented by the addition of sulphuric acid, and they are allowed 
 by law to add one-thousandth part by weight of sulphuric acid. It is now known that 
 this is unnecessary ; nevertheless the practice is still continued. 
 
 DISTILLED VINEGAR. By submitting wine or malt vinegar to distillation it is deprived 
 of its colouring and other non- volatile matters, a colourless limpid liquid being obtained 
 which is known in commerce as distilled vinegar. The product is, however, always 
 weaker than the vinegar from which it has been derived, because the boiling point of 
 strong acetic acicl is above that of water ; it is also liable to be contaminated with a 
 small quantity of alcohol and empyreumatic bodies. 
 
 2. From Wood. WOOD VINEGAR, or PYROLIGNEOUS ACID. The greater part of the 
 acetic acid now employed in the arts is obtained by the destructive distillation of wood. 
 The wood is heated in large iron cylinders like gas retorts, connected with a series of 
 condensing vessels, the uncondensable gases which are evolved in large quantity being 
 conveyed by pipes into the fire and aiding to maintain the heat. The liquid which 
 condenses in the receivers consists of water, tar, wood-spirit or methylic alcohol, 
 acetate of methyl, and acetic acid. The watery liquid, after being separated from the 
 tar, is redistilled, the wood-spirit passing over among the first portions of the distillate, 
 and the acetic or pyroligneous acid afterwards. The acid thus obtained is coloured, 
 and has a strong tarry flavour, which cannot be removed by redistillation. To purify 
 this crude acid, it is converted into acetate of sodium, either by direct saturation with 
 carbonate of sodium, or more economically by saturating it with carbonate of calcium, 
 and decomposing the calcium-salt with sulphate of sodium; and the acetate of sodium is 
 purified from tarry matter, first by gentle torrefaction, and afterwards by recrystallisa- 
 tion. It is then decomposed by strong sulphuric acid diluted with half its weight of 
 water, whereupon the sulphate of sodium, being insoluble in acetic acid, separates in 
 the crystalline form, and may be separated by simple decantation ; and the acetic acid 
 thus separated is purified from the last traces of sulphate of sodium by distillation. 
 
 The process just described yields a very pure acid, but it is too expensive, princi- 
 pally in consequence of the large quantity of fuel which it requires. A more economical 
 process has been proposed byVolckel (Ann. Ch. Pharm. Ixxxii. 49 ; Chem. Soc. Qu. J. 
 v. 274). In this process the crude wood-vinegar is immediately saturated with lime, 
 without previous rectification. Part of the tarry matter then separates in combination 
 with the lime, while the rest remains in solution with the acetate of calcium. The liquid, 
 aft or being clarified by repose, or by filtration, is evaporated down to half its bulk in 
 an iron pot, and mixed with a quantity of hydrochloric acid, sufficient to give it a slight 
 acid reaction. The greater part of the tarry matter then separates, and may be skimmed 
 off from the surface. The hydrochloric acid also decomposes certain compounds of the 
 lime with creosote and other volatile substances, which are then expelled by heat ; 33 
 go-lions of crude wood- vinegar require for purification from 4 to 5 Ibs. of hydrochloric 
 acid. The acetate of calcium thus purified is completely dried and distilled with hydro- 
 chloric acid, 100 parts of the dry salt requiring from 90 to 95 parts of hydrochloric acid 
 of sp. gr. 1-15 (or 20 Bm.). The sp. gr. of the acetic acid thus obtained is about 1'06 
 (8 Bm.). If it contains hydrochloric acid, it may be purified by redistillation, with 
 addition of a small quantity of carbonate of sodium, or better, 2 or 3 per cent, of 
 
10 ACETIC ACID. 
 
 bichromate of potassium, which, at the same time, destroys certain organic impurities 
 that impart a peculiar odour to the acid. 
 
 The presence of hydrochloric or sulphuric acid in vinegar is easily detected by boil- 
 ing the liquid for about twenty minutes with a small quantity of potato-starch, then 
 leaving it to cool and adding a few drops of iodide of potassium. If the vinegar is 
 pure, the blue colour of iodide of starch immediately makes its appearance, but not if 
 sulphuric or hydrochloric acid is present, because these acids boiled with starch con- 
 vert it into dextrin, which is not coloured blue by iodine (Pay en). Sulphuric acid 
 may also be detected by chloride of barium, and hydrochloric acid by nitrate of silver. 
 
 [For further details of the manufacture of acetic acid, see the new edition of Ure's 
 Dictionary of Arts, Manufactures and Mines, vol. i. pp. 5 to 20.] 
 
 CRYSTAI/LISABLE or GXACLAX ACETIC Aero. This term is applied to the pure acid 
 C 2 H 4 2 , [or C*H 4 4 ] of sp. gr. 1-0635, because it is at ordinary temperatures a crystalline 
 solid. The acid obtained by either of the processes above described consists of this com- 
 pound more or less mixed with water. On distilling this dilute acid, a weaker acid 
 passes over, and a stronger acid remains behind, because the boiling point of aqueous 
 acetic acid increases with its concentration ; and by repeated fractional distillation, an 
 acid is at length obtained which crystallises at a low temperature. Crystallisable acetic 
 acid is, however, more conveniently obtained by distilling certain acetates in the dry 
 state with an equivalent quantity of concentrated sulphuric acid or disulphate of potas- 
 sium ; thus with acetate of potassium : 
 
 2C 8 H 3 K0 2 + S0 4 H 3 = 2C 2 H 4 8 + SO'K 2 . 
 and: C 2 H 3 K0 2 + S0 4 IIK = C-H 4 2 + S0 4 K 3 . 
 
 The proportions required are 98 pts. of dry acetate of potassium, or 82 acetate of 
 sodium, or 79 acetate of calcium, or 163 acetate of lead, to 49 parts of monohydrated 
 sulphuric acid, S0 4 H 2 , or 136 parts of disulphate of potassium, S0 4 HK. Glacial acetic 
 acid may also be conveniently obtained from diacetate of potassium, C 2 H 3 K0 2 .C 2 H 4 2 
 by simple distillation. When neutral acetate of potassium is mixed with aqueous 
 acetic acid, not too dilute, and distilled, part of the acetic acid unites with the 
 neutral acetate, and a weaker acid passes over. But as the distillation goes on, the 
 acid potassium-salt decomposes, the distillate becomes continually richer in acetic 
 acid, and at length the pure crystallisable acid distils over. The temperature must 
 not be allowed to exceed 300 ; otherwise the acid suffers partial decomposition, and 
 becomes coloured (Me Is ens, Compt. rend. xix. 611). Crystallised acetate of copper 
 also yields glacial acetic acid, when dried at a temperature between 160 and 180 
 and afterwards distilled at a higher temperature. Towards the end of the distillation 
 the acid becomes mixed with acetone : that which passes over towards the middle 
 must be redistilled to free it from copper mechanically carried over, probably in the 
 form of cuprous acetate. The acid obtained by this process was formerly called 
 Spiritua Aeruginis or Spiritus Veneris. 
 
 Properties. Pure acetic acid solidifies at or below 15 C. in prismatic or tabular 
 crystals. In closed vessels it remains liquid at 12, and does not solidify till the 
 vessel is opened and shaken. Its specific gravity in 1 the solid state is 1 -100 at 8*5 
 (Persoz). It melts at 16 (Lowitz), at or above 22-5 (Mollerat), forming a 
 thin colourless liquid of sp. gr. 1*063 (Mollerat) ; T065 at 13 (Persoz) ; 1-0635 at 
 15 (Mohr); 1-0622 (Sebille-Auger); 1-08005 reduced to (Kopp, Pogg. Ann.. 
 Ixxii. 1). It boils at 119 (Sebille-Auger); at 117'3 (Kopp). The density of its 
 vapour is different at different temperatures, compared with an equal bulk of air at 
 the same temperature. At temperatures considerably above the boiling point, it follows 
 the ordinary law of condensation to 2 volumes ; thus at 300 and upwards the sp. gr. of 
 the vapour is found by Cahours to be 2*00, which agrees almost exactly with the calcu- 
 lated density, supposing the molecule to occupy 2 volumes. For the atomic weight of 
 acetic acid, compared with hydrogen as unity is 60 (= 2C + 4H + 20 = 24 + 4 + 32); 
 and if this be the weight of 2 volumes of the vapour, it follows that the weight of 
 1 volume of vapour, or in other words, the specific gravity as compared with hydrogen, 
 will be 30 ; and multiplying this number by 0-0693, the sp. gr. of hydrogen referred 
 to air as unity, we obtain for the sp. gr. of acetic acid vapour referred to air as unity, 
 the number 2'079. 
 
 But at temperatures near the boiling point, the density of the vapour is much 
 greater, exhibiting a condensation to |- volume, or even less. The following table ex- 
 hibits the den ity of the vapour at various temperatures as determined by Cahours 
 (Compt. rend. xix. 771 ; xx. 51) : 
 
 Temperature. 125 130 140 150 160 170 190 200 230 250 300 
 Density. 3'20 3'12 2-90 275 2-48 2'42 2'30 2-22 2-17 2'09 2'08 
 
 The tension of the vapour is 7mm. at 15; 14'5mm. at 22, and 32mm. at 32. 
 (Bincau, Ann. Ch. Phys. [3] xviii. 226.) 
 
ACETIC ACID. 
 
 11 
 
 The acid has a pungent sour taste and odour, blisters the skin, and acts as an acrid 
 poison. It does not redden litmus paper per se, but very strongly when mixed with 
 water. 
 
 Decompositions. 1. The vapour of acetic acid is inflammable, and burns with a 
 blue flame, producing water and carbonic acid. When it is passed through a red-hot 
 tube, the greater part remains unaltered, but a portion is decomposed, yielding free 
 carbon and combustible gases, together with acetone, napthalin, hydrate of phenyl and 
 benzol. (Berthelot, Ann. Ch. Phys. [3] xxxiii. 295.) 
 
 2. A mixture of glacial acetic and strong sulphuric acid blackens when heated, 
 giving off carbonic and sulphurous anhydrides. Fuming sulphuric acid mixes with 
 glacial acetic acid without evolution of gas ; but the mixture becomes hot, and if it be 
 raised to a higher temperature, carbonic anhydride is given off, mixed with only a small 
 quantity of sulphurous anhydride. Sulphuric anhydride dissolves in acetic acid without 
 evolution of gas, and on heating the mixture, sulphacetic acid is produced. 
 
 3. Acetic acid is not sensibly attacked by nitric acid. 
 
 4. Periodic acid converts it into carbonic or formic acid, with formation of iodic 
 acid and separation of iodine. 
 
 5. Chlorine in sunshine converts acetic acid into monochloracetic and trichloracetic 
 acids, the quantity of the one or the other being greater, according as the acetic acid 
 or the chlorine is in excess. See CHLORACETIC ACID. 
 
 6. Glacial acetic acid heated with bromine in a sealed tube forms bromacetic and 
 dibromacetic acids. Iodine has no action on acetic acid even in sunshine. 
 
 7. With pentachloride of phosphorus, glacial acetic acid forms hydrochloric acid, 
 chloride of acetyl and oxychloride of phosphorus : 
 
 C 2 H 3 O.H.O + PCP.Cl 3 = C 2 H 3 O.C1 + HC1 + PO.C1 3 . 
 
 8. With pentasulphide of phosphorus, it forms thiacetic acid and phosphoric 
 anhydride : 
 
 5(C 2 H 3 O.H.O) + P 2 S 5 = P ? 5 + 5(C 2 H 3 O.H.S). 
 
 The difference between the mode of action of the pentachloride and pentasulphide 
 of phosphorus, the former giving rise to two distinct chlorine-compounds, C 2 H 3 O.C1 and 
 HC1, whereas the latter forms only one sulphur-compound, is very remarkable, and 
 shows clearly the propriety of regarding chlorine as a monatomic, and sulphur as a 
 diatomic radicle. 
 
 AQUEOUS ACETIC ACID. Acetic acid mixes with water in all proportions, impart- 
 ing to it its taste and smell. The density of the aqueous acid varies with its 
 strength in a remarkable manner. When water is gradually added to glacial acetic 
 acid, the density increases till a hydrate is formed containing 79 pts. of crystallised 
 acid to 21 water, and having the composition C 8 H 4 0*. H 2 0. This hydrated acid has 
 a density of T073 and boils at 104. All further additions of water diminish the 
 density of the acid. 
 
 The following table constructed by Mohr (Ann. Ch. Pharm. xxxi. 277) gives 
 the quantity of crystallisable acetic acid in 100 pts. of the aqueous acid of different 
 densities. 
 
 Perc. 
 
 Sp. Gr. 
 
 Perc. 
 
 Sp. Gr. 
 
 Perc. 
 
 Sp. Gr. 
 
 Perc. 
 
 Sp. Gr. 
 
 Perc. 
 
 Sp. Gr. 
 
 100 
 
 1-0635 
 
 80 
 
 1-0735 
 
 60 
 
 1-067 
 
 40 
 
 1-051 
 
 20 
 
 1-027 
 
 99 
 
 1-0655 
 
 79 
 
 1-0735 
 
 59 
 
 1-066 
 
 39 
 
 1-050 
 
 19 
 
 1-026 
 
 98 
 
 1-0670 
 
 78 
 
 1-0732 
 
 58 
 
 1-066 
 
 38 
 
 1-049 
 
 18 
 
 1-025 
 
 97 
 
 1-0680 
 
 77 
 
 1-0732 
 
 57 
 
 1-065 
 
 37 
 
 1-048 
 
 17 
 
 1-024 
 
 96 
 
 1-0690 
 
 76 
 
 1-0730 
 
 56 
 
 1-064 
 
 36 
 
 1-047 
 
 16 
 
 1-023 
 
 95 
 
 1-0700 
 
 75 
 
 1-0720 
 
 55 
 
 1-064 
 
 35 
 
 1-046 
 
 15 
 
 1-022 
 
 94 
 
 1-0706 
 
 74 
 
 1-0720 
 
 54 
 
 1-063 
 
 34 
 
 1-045 
 
 14 
 
 1-020 
 
 93 
 
 1-0708 
 
 73 
 
 1-0720 
 
 53 
 
 1-063 
 
 33 
 
 1-044 
 
 13 
 
 1-018 
 
 92 
 
 1-0716 
 
 72 
 
 1-0710 
 
 52 
 
 1-062 
 
 32 
 
 1-042 
 
 12 
 
 1-017 
 
 91 
 
 1-0721 
 
 71 
 
 1-0710 
 
 51 
 
 1-061 
 
 31 
 
 1-041 
 
 11 
 
 1-016 
 
 90 
 
 1-0730 
 
 70 
 
 1-0700 
 
 50 
 
 1-060 
 
 30 
 
 1-040 
 
 10 
 
 1-015 
 
 89 
 
 1-0730 
 
 69 
 
 1-0700 
 
 49 
 
 1-059 
 
 29 
 
 1-039 
 
 9 
 
 1-013 
 
 88 
 
 1-0730 
 
 68 
 
 1-0700 
 
 48 
 
 1-058 
 
 28 
 
 1-038 
 
 8 
 
 1-012 
 
 87 
 
 1-0730 
 
 67 
 
 1-0690 
 
 47 
 
 1-056 
 
 27 
 
 1-036 
 
 7 
 
 1-010 
 
 86 
 
 1-0730 
 
 66 
 
 1-0690 
 
 46 
 
 1-055 
 
 26 
 
 1-035 
 
 6 
 
 1-008 
 
 85 
 
 1-0730 
 
 65 
 
 1-0680 
 
 45 
 
 1-055 
 
 25 
 
 1-034 
 
 5 
 
 1-007 
 
 84 
 
 1-0730 
 
 64 
 
 1-0680 
 
 44 
 
 1-054 
 
 24 
 
 1-033 
 
 4 
 
 1-005 
 
 83 
 
 1-0730 
 
 63 
 
 1-0680 
 
 43 
 
 1-053 
 
 23 
 
 1-032 
 
 3 
 
 1-004 
 
 82 
 
 1-0730 
 
 62 
 
 1-0670 
 
 42 
 
 1-052 
 
 22 
 
 1-031 
 
 2 
 
 1-002 
 
 81 
 
 1-0732 
 
 61 
 
 1-0670 
 
 41 
 
 1-051 
 
 21 
 
 1-029 
 
 1 
 
 1-001 
 
12 ACETIC ACID. 
 
 M oiler at, Ann. Cliim. Ixviii. 88, and Ad. van Toorn (J. pr. Chem. vi. 171) have 
 also given tables of the specific gravities of acetic acid of different degrees of concen- 
 tration. 
 
 It will be seen from the preceding table that the specific gravity of acetic acid varies 
 but slowly, a difference of 1 per cent, corresponding to a difference of only -001 in the 
 density, and sometimes even less. For this reason, the determination of the strength 
 of commercial acetic acid by the hydrometer or acetometer, as it is called when gra- 
 duated for this purpose, is not much to be depended on. The presence of colouring 
 matter, saline substances and other impurities, which frequently occur in vinegar, are of 
 course an additional source of inaccuracy in this method of estimation. It is better, 
 therefore, to determine the strength of the acid -by ascertaining the quantity of a 
 standard solution of caustic soda or ammonia, reqiiired to neutralise a given volume. 
 (See ACIDIMETRY and ANALYSIS, VOLUMETRIC.) This method, when applied to acetic acid, 
 is affected with a slight source of inaccuracy, arising from the fact that the normal or 
 neutral acetates of the alkalis exhibit a slight alkaline reaction. The error thence 
 arising is, however, of small amount, not exceeding ^ per cent, for an acid containing 
 10 per cent, of crystallisable acetic acid, as shown by Otto (Ann. Ch. Pharm. cii. 69). 
 Moreover, it may be completely obviated by iising a solution of caustic soda, graduated 
 for the purpose by means of a solution of pure acetic acid of known strength (ANALYSIS, 
 VOLUMETRIC). Greville Williams (Pharm. J. Trans, xiii. 594) recommends for the 
 volumetric estimation of acetic acid a graduated solution of lime in sugar- water. 
 
 Acetic acid mixes in all proportions with alcohol. It dissolves resins, gum-resins, 
 c';KD])lior, and essential oils. Its use for culinary purposes is well known. Its odour 
 is employed in medicine to relieve nervous head-ache, fainting fits, or sickness occa- 
 sioned by crowded rooms. Pungent smelling salts consist of sulphate of potassium 
 moistened with glacial acetic acid. Pyroligneous acid is largely used in calico-printing ; 
 the tar and empyreumatic substances present in it appear to be rather advantageous 
 than otherwise for that purpose. Large quantities of acetic acid are also used for the 
 preparation of the acetates of lead, copper, aluminium, &c. (See Dictionary of Arts, 
 Manufactures, and Mines.) 
 
 .Acetates. Acetic acid is monobasic, the general formula of its normal salts being 
 C 3 H S 8 .M [or C*H 3 0\M = C H H 3 O 3 .MO], the symbol M denoting a metal. It also 
 forms basic salts, which may be regarded as compounds of the normal acetates with 
 oxides. The normal acetates all dissolve in water, and most of them readily. The 
 least soluble are the silver and mercury salts, so that solutions of other acetates added 
 to mercurous nitrate or nitrate of silver, throw down white shining scales of mercurous 
 acetate or silver-acetate ; but generally speaking, acetates are not formed by precipita- 
 tion : they are produced by the action of acetic acid on metallic oxides or carbonates ; 
 many carbonates, however, the barium and calcium salts, for example, are not decom- 
 posed by acetic acid in its most concentrated state, but only after addition of water. 
 
 All acetates are decomposed by heat, most of them yielding carbonic anhydride, ace- 
 tone and an empyreumatic oil. Those which are easily decomposed, and likewise contain 
 bases forming stable carbonates, are almost wholly resolved into acetone and a car- 
 bonate of the base ; this is especially the case with acetate of barium : 
 2C-II 3 2 Ba --= C S II G + CCPBa 2 . 
 
 Those which, like the potassium and sodium salts, require a higher temperature to de- 
 compose them, yield more complex products, but always a certain quantity of acetone. 
 Among the products are found certain homologues of acetone, viz. methylacetone 
 C S H 5 (CH 3 )0 and ethyl acetone C 3 H 5 (C 2 H 5 )0, together with dumasin C 6 H I0 0. (Fittig, 
 Ann. Ch. Pharm. ex. 17). Acetates containing weaker bases, give off part of the 
 acetic acid undecomposed, the remaining portion being resolved into acetone and 
 carbonic anhydride, or if the heat be strong, yielding empyreumatic oil and charcoal : the 
 residue consists sometimes of oxide, sometimes, as in the case of copper and silver, of 
 reduced metal ; in this case part of the acetic acid is burnt by the oxygen abstracted 
 from the metal. Acetates heated with a large excess of fixed caustic alkali, are resolved 
 at a temperature below redness into marsh gas and alkaline carbonate, e. g. : 
 C-H 3 K0 2 + KHO = CII 4 f C0 3 K 2 . 
 
 Acetates distilled with sulphuric acid, give off the odoxir of acetic acid, and yield a 
 distillate which dissolves oxide of lead, and acquires thereby an alkaline reaction. Dis- 
 til led with sulphuric and" alcohol, they yield acetate of ethyl, recognisable by its odour. 
 The neutral acetates impart to solutions of ferric salts a reddish yellow or red-brov, 11 
 colour, according to the degree of dilution. Acetates heated to redness with ar- 
 penious acid give off the odour of cacodyl. The acetates of the alkali-metals, and 
 probably others also, treated with oxychloride of phosphorus, yield chloride of acetyl, 
 together with a tribasic phosphate: 
 
 3(C-IPO.Na.O) + PO.CP = 3C 2 H'OC1 + PO'Na". 
 
ACETIC ACID. 13 
 
 ACETATES OF ALUMINIUM. a. Triacetate. As aluminium is sesquiatomic (Al 2 being 
 equivalent to H 3 or Al^ to H) the normal salt should be a triacetate C 2 H 3 2 .A13 or 
 
 (C 2 H 3 2 ) S .A1 8 , [or AP0 5 .3C 4 H 3 3 , regarding it as a compound of alumina with an- 
 hydrous acetic acid]. This salt, however, exists only in solution, and is decomposed 
 by evaporation. The solution is obtained by digesting recently precipitated trihydrate 
 of aluminium in strong acetic acid, or by precipitating a solution of the trisulphate 
 with acetate of lead : 
 
 (S0 4 ) 3 A1 4 + 6C 2 H s 2 Pb = 3S0 4 Pb 2 + 2(C 2 H 3 2 ) 3 A1 2 . 
 
 This salt is largely used as a mordant in dyeing and calico-printing, and is generally 
 prepared for this purpose by precipitating alum with acetate of lead. The solution 
 thus formed contains sulphate of potassium as well as acetate of aluminium. 
 
 /3. Diacetate. When the solution of the triacetate obtained by decomposing trisul- 
 phate of aluminium with acetate of lead is evaporated at a low temperature, with 
 sufficient rapidity, as by spreading the concentrated liquid very thinly on plates of 
 glass or porcelain, exposing it to a temperature not exceeding 100 F. (37*7 C.), and, 
 as it runs together in drops, rubbing it constantly with a spatula, diacetate of aluminium 
 
 remains in the form of a dry powder containing ^ , 4 ' ( O 4 + 5H 2 [or, using the 
 
 smaller atomic weights of carbon and oxygen, 2C*H 3 0*.A1 2 3 + 5HO}. The diacetate 
 thus obtained dissolves easily and completely in water, and the solution when heated 
 deposits dihydrate of aluminium soluble in water. (See ALUMINIUM.) But when the 
 solution, instead of being quickly evaporated, is left to itself in the cold for some days, 
 it deposits a white saline crust, which is an allotropic diacetate of aluminium insoluble in 
 water. Heat effects the same change more rapidly, and the insoluble diacetate then 
 separates in the form of a granular powder. At the boiling temperature, the liquid is 
 thus deprived in half an hour of the whole of its alumina, which goes down with f of 
 the acetic acid, leaving | in the liquid. The insoluble diacetate digested in a large 
 quantity of water is gradually changed into the soluble modification, part of which is, 
 however, decomposed during the process into acetic acid and the soluble dihydrate. 
 (Walter Crum, Chem. Soc. Qu. J. vi. 217.) 
 
 ACETATES OF AMMONIUM. a. Normal acetate. C 2 H 3 2 .NH 4 . A white odourless salt, 
 obtained by saturating glacial acetic acid with dry ammonia. It is very difficult to 
 obtain it in the crystalline form : for its aqueous solution loses ammonia on evapora- 
 tion, and is converted into the acid salt (/3). It is readily soluble in water and alcohol. 
 Its aqueous solution, known in the Pharmacopeia as Spiritus Mindereri, is prepared by 
 saturating aqueous acetic acid with ammonia or carbonate of ammonium. This solution 
 is transparent and colourless, with a peculiar odour and cooling pungent taste. 
 When kept it is decomposed, and becomes alkaline, owing to the formation of carbonate 
 of ammonium ; by heat it is converted into a solution of the acid salt ()8). 
 
 . Acid Acetate, C 2 H 3 2 .NH 4 .C 2 H 4 2 [or C t H 3 3 .NH 4 + C*H 3 3 .HO]. Obtained 
 as a white crystalline sublimate when dry powdered chloride of ammonium is heated 
 with an equal weight of acetate of potassium or calcium, ammonia being given off 
 simultaneously. A warm saturated solution of this salt, kept in a closed bottle de- 
 posits long needle-shaped crystals. This salt is also obtained in a radiated crystalline 
 mass, by evaporating the aqueous solution of the normal salt (a). The crystals redden 
 litmus and deliquesce rapidly in the air. They melt at 76C. and sublime undecomposed 
 at 121. The composition of this salt is probably that expressed by the above formula. 
 
 ACETATE OF BARIUM, C 2 H 3 8 Ba. Prepared by decomposing carbonate or sulphide 
 of barium with acetic acid. The solution evaporated at a gentle heat yields flattened 
 prisms containing 2C 2 H 3 0-Ba + H 2 0, but when cooled to C. it yields rhomboidal 
 prisms, isomorphous with acetate of lead, and containing 2C 2 H 3 2 Ba + 3H 2 0. The 
 crystals dried at yield the anhydrous salt in the form of a white powder, which, 
 when strongly heated, is resolved into acetone and carbonate of barium. 
 
 ACETATE OF BISMUTH separates in micaceous laminae from a warm mixture of 
 nitrate of bismuth and acetate of potassium. Acetic acid mixed with a solution of 
 nitrate of bismuth prevents the precipitation of a basic salt of that metal by water. 
 
 ACETATE OF CADMIUM. Small prismatic crystals very soluble in water (Stromeyer). 
 According to Meissner and John, it is not crystallisable, but forms a gelatinous mass. 
 
 ACETATE OF CALCIUM, C 2 H 3 2 Ca, crystallises in prismatic needles, which effloresce 
 in the air, and dissolve in water and in alcohol. The salt is decomposed by heat 
 into acetone and carbonate of calcium. A solution of acetate and chloride of cal- 
 cium in equivalent proportions yields by slow evaporation, large crystals containing 
 C 2 H 3 2 Ca.ClCa + 5H 0. 
 
 ACETATE OF CERIUM. Small needles sparingly soluble in alcohol. 
 
14 ACETIC ACID. 
 
 ACETATES OF CHROMIUM. The chromous salt, 2C 2 H 3 2 Cr + H 2 is, produced by 
 pouring protochloride of cliromium into a solution of acetate of potassium or sodium. It 
 forms red transparent crystals, which when moist absorb oxygen very rapidly from the 
 air, undergoing a true combustion. The chromic salt is obtained as a green crystalline 
 crust, very soluble in water, by dissolving chromic hydrate in acetic acid : the so- 
 lution scarcely reddens litmus. 
 
 ACETATES OF COBALT. The red liquid formed by dissolving carbonate of cobalt in 
 acetic acid, yields by evaporation a red residue which turns blue when heated. It 
 may be used as a sympathetic ink. The oxides Co 4 3 and Co 3 2 also dissolve in 
 acetic acid without separation of oxygen, forming brown solutions. The solution of 
 the sesquioxide sustains a boiling heat without decomposition. 
 
 ACETATES OF COPPER. a. Cuprous Acetate, C 2 H 3 2 Ccu. [Ccu = Cu 2 = 63-2]. This 
 salt sublimes towards the end of the distillation of normal cupric acetate. According 
 to Berzelius, it is contained in common green verdigris, and sublimes when that sub- 
 stance is distilled. It forms soft, loose, white flakes, which redden litmus and have a 
 caustic astringent taste. Water decomposes it into normal cupric acetate and yellow 
 cuprous hydrate. 
 
 b. Cupric Acetates. (Berzelius, Pogg. Ann. ii. 233; Traite, iv. 173; Gm. viii. 
 323; G-erh. i. 728.) Four of these salts are known, viz. : 
 
 Normal Cupric Acetate C 2 H 3 2 Cu = C*H 3 3 . CuO. 
 
 Sesquibasic. . . (C 2 H 3 2 Cu) 4 . Cu ? = (C 1 H 3 3 )*. (CuO) 3 . 
 
 Dibasic . . . (C 2 H 8 2 Cu) 2 . Cu 2 = C*H*C* . (CuO)*. 
 
 Tribasic . . . C 8 H 3 OCu . Cu 2 O = C t H 3 3 . (CuO) 9 . 
 
 1. The normal salt C 2 H 3 2 Cu, called also Crystallised Verdigris, Verdet, Cristaux 
 de Venus, is produced by dissolving cupric oxide or common verdigris in acetic acid, or 
 by precipitating a solution of normal acetate of lead with sulphate of copper : in either 
 case, the liquid must be highly concentrated and then left in a cool place. It 
 forms dark bluish-green prisms belonging to the monoclinic system, and containing 
 2C*H 3 2 Cu + H 2 O. The ordinary combination is ooP . OP . + P.-r2Po>. Twin- 
 crystals also occur. Eatio of the axes: a : b: c = 0'6473 1 : 0-5275. Inclination 
 of the axes => 63. Inclination of the faces, ooP : ooP in the plane of the ortho- 
 diagonal and the principal axis = 108 ; ooP : OP - 105 30' ; OP : 4 2Pco = 
 119 4'. Cleavage parallel to OP and QO P. The salt is efflorescent, soluble in water, 
 sparingly soluble in alcohol, and poisonous like all soluble copper-salts. The crystals 
 after drying in vacuo at ordinary temperatures, suffer no further diminution in weight 
 at 100, but give off 9-6 per cent, of water between 110 and 140, then nothing more 
 below 240 ; between 240 and 260 strong acetic acid, which when rectified yields 32 
 per cent, of the crystallisable acid ; at 270 white fumes which condense into white flakes 
 of cuprous acetate ; and lastly a mixture of carbonic anhydride and a combustible gas. 
 At 330 the decomposition is complete, and a reddish substance remains consisting 
 chiefly of metallic copper. The solution boiled with sugar yields a red precipitate of 
 cuprous oxide. Acetate of copper crystallised at a temperature near 8, yields crystals 
 containing 2C 2 H 3 Cu + 5H 2 0. 
 
 2. The basic cupric acetates are contained in common verdigris (vert-de-gris, 
 Griinspan), a substance obtained by exposing plates of copper to the. air in contact 
 with acetic acid, and much used as a pigment and as a mordant in dyeing wool black. 
 There are two varieties of this substance, the blue and the green, the former consist- 
 ing almost wholly of dibasic cupric acetate, the latter of the sesquibasic salt mixed 
 with smaller quantities of the dibasic and tribasic acetates. The dibasic salt or blue 
 verdigris is prepared at Montpellier and in other parts of the south of France, by ex- 
 posing copper to the air in contact with fermenting wine-lees. The wine-lees are 
 loosely packed in casks together with straw, till they pass into the state of acetous fer- 
 mentation ; and when that is ended, they are arranged in pots covered with straw, in 
 alternate layers with rectangular plates of copper, which when used for the first time, are 
 previously moistened with a cloth dipped in a solution of normal acetate of copper, and 
 then dried. At the end of three weeks, the plates are taken out ; placed in an upright 
 position to dry ; dipped six or eight times in water in the course of as many weeks ; and 
 again left to dry, during which operations the verdigris continually swells up. It is 
 then scraped off, the plates again arranged alternately with sour wine-lees, and the 
 same processes are repeated till the plates are quite corroded. The same compound is 
 obtained by exposing copper plates to damp air in contact with normal acetate of copper 
 made into a paste with water. It forms delicate, silky, blue, crystalline needles and scales, 
 which yield a beautiful blue powder. They contain 6 at. water, which they give off at 
 60, and are then converted into a green mixture of the monobasic and tribasic salt : 
 
 (C 2 H 3 0-Cu) 8 .Cu 2 = C 2 H 3 2 Cu + C 2 TF0 2 Cu . Cu'O. 
 
ACETIC ACID. 15 
 
 By repeated exhaustion with water, it is resolved into the insoluble tribasic salt, 
 and a solution of the normal and sesquibasic salts : 
 
 5(C 4 H 6 3 .2Cu 8 0) = 2(C 4 H 6 3 .3Cu 2 0) + 2C 4 H 6 3 .3Cu a O + C 4 H 6 3 .Cu 2 0. 
 
 The following table exhibits the composition of several kinds of blue verdigris as 
 determined by Berzelius and by Phillips : 
 
 Phillips. 
 
 French. English. 
 
 Calculation. Berzelius. Crystallised. Compressed. 
 
 2Cu s O . . 160 . 43-24 . 43-34 . 43-5 . 43'25 . 44-25 
 
 C 4 H 6 3 . . 102 . 27-57 . 27'45 . 29-3 . 28-30 . 29-62 
 
 6H 2 O . . 108 . 29-19 . 29-21 . 25-2 . 28'45 . 25-51 
 
 Impurities 2-0 . . . . 0*62 
 
 370 . 100-00 . 100-00 . 100-0 . 100-00 . 100-00 
 
 The sesquibasic acetate is obtained in a state of purity by adding ammonia in small 
 portions to a boiling concentrated solution of the normal salt, till the precipitate is just 
 redissolved, and leaving the solution to cool; or by treating common green ver- 
 digris with cold or tepid water, and leaving the filtrate to evaporate. It is then 
 deposited in bluish scales containing (C 2 H 3 2 Cu) 4 . Cu 2 + 6H 2 0. It gives off half 
 its water at 60, and becomes greenish. 
 
 Green Verdigris, according to Berzelius, is a mixture of this salt with small quan- 
 tities of the dibasic and tribasic salts, sometimes also containing cuprous acetate and other 
 impurities. It is manufactured at Grenoble by frequently sprinkling copper-plates 
 with vinegar in a warm room ; and in Sweden by disposing copper-plates in alternate 
 layers with flannel cloths soaked in vinegar, till the green salt begins to form, then 
 exposing them to the air and frequently moistening with water. The greenest 
 kind contains according to Berzelius, 49-9 per cent, of cupric oxide, and 13*5 per cent, 
 of water and impurities ; the pure sesquibasic salt contains 43*5 per cent. Cu'-'O. 
 
 The tribasic acetate, C-'H 3 2 Cu.Cu-0 + H 2 0, is the most stable of aU the acetates of 
 copper. It is obtained by exhausting blue verdigris with water ; also by boiling the 
 aqueous solution of the normal salt, or by heating it with alcohol, or again by digesting 
 the same solution with cupric hydrate. The last method yields the salt in the form of a 
 green powder ; as obtained by the other methods, it forms a bluish powder composed of 
 fine needles or scales. It gives off its water at 160, and decomposes at a higher tem- 
 perature, yielding acetic acid. Boiling water decomposes and turns it brown. The 
 brown substance thus formed was regarded by Berzelius as a peculiar basic acetate, 
 containing C 4 H 6 3 . 48Cu 2 ; but it is more probably a mixture of the tribasic salt 
 with excess of oxide. 
 
 Acetate of Copper and Calcium. C 2 H 3 9 Ca . C 2 H 3 2 Cu + 4H 2 0. Obtained by 
 heating a mixture 1 atom of normal cupric acetate and 1 atom hydrate of calcium 
 with 8 times its weight of water and sufficient acetic acid to dissolve the precipitated 
 oxide of copper, and evaporating the green filtrate at a temperature between 25 
 and 27. It forms large, blue, transparent, square prisms, often converted into 
 octagonal prisms by truncation of the lateral edges. They effloresce slightly in the 
 air ; fall to powder at 75, giving off acetic acid ; and dissolve readily in water. An- 
 other cuprico-calcic acetate, C'-'H s 2 Ca + (C 2 H 3 O 2 Cu). Cu 2 + 2H 2 0, often exists in 
 crystallised verdigris : its optical properties differ from those of the normal cupric 
 acetate. 
 
 Aceto-arsenite of Copper. C 2 H 3 2 Cu.3As0 2 Cu, or C*H 3 0*.CuO + 3(AsO*.CuO'). 
 Schweinfurt green, Imperial green, Mitis green, and when mixed with gypsum or heavy 
 spar, Neuwieder green, Mountain green. Used as a pigment, and prepared on the large 
 scale by mixing arsenious acid with cupric acetate and water. 5 parts of verdigris are 
 made up to a thin paste, and added to a boiling solution of 4 parts or rather more of 
 arsenious acid in 50 parts of water. The boiling must be well kept up, otherwise the pre- 
 cipitate assumes a yellow-green colour, from formation of arsenite of copper; in that case, 
 acetic acid must be added, and the boiling continued a few minutes longer. The precipi- 
 tate then becomes crystalline, and acquires the fine green colour peculiar to the aceto- 
 arsenite. The salt is insoluble in water, and when boiled with water for a considerable 
 time, becomes brownish and gives up acetic acid. Acids abstract the whole of the 
 copper, and aqueous alkalis first separate blue cupric hydrate, which when boiled with 
 the liquid, is converted into black cupric oxide, and afterwards into red cuprous oxide, 
 an alkaline arsenate being formed at the same time. 
 
 ACETATES OF IRON. a. Ferrous Acetate. When metallic iron or the protosulphide 
 is dissolved in strong acetic acid, and the solution concentrated, small colourless silky 
 needles are obtained, which dissolve easily in water, and rapidly absorb oxygen from 
 the air. 
 
16 ACETIC ACID. 
 
 0. Ferric Acetate. Obtained by dissolving ferric hydrate in acetic acid, or by decom- 
 posing a solution of ferric sulphate with acetate of lead. It is uncrystallisable and 
 very soluble in water, forming a red-brown solution; soluble also in alcohol. The 
 aqueous solution, when kept in a state of ebullition for about 12 hours, undergoes a 
 remarkable modification, acquiring a brick-red colour, and remaining clear when 
 viewed by transmitted light, but appearing opaque and opalescent by reflected light. 
 At the same time, it loses entirely the metallic taste of iron salts, and acquires that of 
 vinegar ; it forms a brown instead of a blue precipitate with ferrocyanide of potassium, 
 and no longer exhibits the characteristic red colour with sulphocyanides. Traces of 
 sulphuric or phosphoric acid, or of alkaline salts, precipitate the whole of the iron in 
 the form of a red-brown precipitate, which, at ordinary temperatures, is perfectly in- 
 soluble in acids, even the most concentrated; hydrochloric and nitric acids throw 
 down a red granular precipitate, which, when perfectly freed from the acid mother- 
 liquor, dissolves easily and completely in water. (P6an de St. Grilles, Ann. Ch. 
 Phys. [3] xlvi. 47.) 
 
 A mixture of the two acetates of iron, called pyrolignite of iron (liqueur de ferraille, 
 bouillon noir\ is prepared on the Jarge scale by treating iron with wood-vinegar, in 
 contact with the air. It is used as a mordant for black dyes ; also for preserving 
 wood. 
 
 ACETATES OF LEAD. The normal acetate C'IF0 2 Pb, or PbO.&irO* (Sugar of lead, 
 saccharum Saturni, sel de Saturne, Bleizucker) is prepared by dissolving oxide or 
 carbonate of lead in acetic acid, wood-vinegar being used on the large scale, or by 
 immersing plates of lead in vinegar in vessels exposed to the air. It crystallises in 
 prisms containing 2O'H s O-Pb + H 2 0, and belonging to the monoclinic system. 
 Ordinary combination : oo P . OP . oo P oo , sometimes with the face OP predominating, 
 so as to give the crystals a tabular form. The length of the orthodiagonal is to that of 
 the clino-diagonal, as 0'4197 to 1. Inclination of the axes = 70 28'. Inclination 
 of the faces : oo P : oo P = 128; oo P : oo Poo = 116 ; oo P : OP = 98 30' ; 
 OP : oo P oo = 109 32. Cleavage parallel to OP and oo P oo . The crystals are 
 efflorescent, soluble in 0'59 parts of water at 15'5 (60 F.), and in 8 parts of alcohol. 
 The salt has a sweet, astringent taste, and is very poisonous. It melts at 75'5 ; begins 
 to give off water with a portion of its acid a little above 100 ; and is completely de- 
 hydrated at 280. Above that temperature it decomposes, giving off acetic acid, 
 carbonic anhydride, and acetone, and leaving metallic lead very finely divided and highly 
 combustible. The aqueous solution is partially decomposed by the carbonic acid of 
 the air, carbonate of lead being precipitated, and a portion of acetic acid set free, 
 which prevents further decomposition. The solution is not precipitated by ammonia 
 in the cold, but yields crystals of oxide of lead when heated with a large excess of 
 ammonia. Normal acetate of lead forms crystalline compounds with chloride of lead 
 and with peroxide of lead. 
 
 (Berzelius, Ann. Chim. xciv. 292 ; Schindler, Brande's Archiv, xli. 129; Payen, 
 Ann. Ch. Phys. [2] Ixv. 238, and Ixvi. 37; Wittstein, Buchner's Eepert. Ixxxiv. 
 170; G-m. viii. 310; Gerh. i. 736.) 
 
 Four basic acetates of lead have been described, viz. : 
 
 The sesquibasic acetate . (C'IFOTb) 4 . Pb 2 or (C*H*0*y. (PbOf. 
 
 The dibasic . (C 2 H 3 2 Pb)X Pb 2 or C*H*0* . (PW)\ 
 
 The tribasic . C-H 3 2 Pb . Pb 8 or C*H 3 O 3 . (P60) s . 
 
 Thesexbasic . (C'H 3 2 Pb) 2 .(Pb 2 0)or C*H 3 0* . (PbO) 6 . 
 
 All of these however, except the tribasic salt, are of rather doubtful composition. 
 
 The sesquibasic salt is obtained by heating the normal salt till it melts, and subse- 
 quently solidifies in a white porous mass. By dissolving the residue in water and eva- 
 porating, the salt is then obtained in nacreous laminse containing 2 [(C 2 H 8 0~Pb) 4 .Pb 2 0] 
 + H 2 0. It is more soluble in water and alcohol than the normal acetate, and forms 
 alkaline solutions. (Payen, Schindler.) 
 
 The dibasic acetate is deposited in the crystalline form when oxide of lead (massicot) 
 is dissolved in the proper proportion in the normal acetate. The crystals contain 
 2 atoms water, half of which is given off at 70, and the rest at 100. (Schindler.) 
 
 The tribasic acetate is obtained in the crystalline form, when a solution of the normal 
 salt saturated in the cold and mixed with f of its volume of ammonia, is left to 
 evaporate ; also by digesting 7 parts of massicot in a solution of 6 parts of the crys- 
 tallised normal acetate. It forms long silky needles, very soluble in water, but in- 
 soluble in alcohol. The aqueous solution becomes turbid on exposure to the air. 
 According to Payen, the crystals contain 2(C 2 H 3 2 Pb . Pb 2 0) + H'O, but according 
 to Berzelius, they are anhydrous. 
 
 The sexbasic salt is obtained by digesting the solution of either of the preceding 
 salts with excess of oxide of lead. A crystalline precipitate is then formed, which 
 
ACETIC ACID. 17 
 
 dissolves sparingly in boiling water, and separates in silky needles containing 
 2[(C 2 H 3 2 Pb) 2 .(Pb v O) 5 ] + 3H'0. (Berzelius.) 
 
 Tho liquid called Goulard's lotion, lead-vinegar, acetum Batumi, is a mixture of 
 the aqueous solutions of these basic acetates of lead, chiefly the tribasic salt. It is 
 prepared by digesting oxide of lead in acetic acid, or in a solution of the normal acetate. 
 It is an alkaline liquid which is decomposed by the carbonic acid in the air. It pre- 
 cipitates a large number of vegetable substances, such as gum-resins, colouring matters, 
 &c. and from its power of coagulating mucus, is much used as a lotion for wounds 
 and sores. 
 
 ACETATE OF LITHIUM. C 2 H 3 2 Li + 2 H 2 0. Eight rhomboi'dal prisms, deliquescent 
 in moist air, soluble in less than a third of their weight of water at 15, and in 4 "6 pts. 
 of alcohol of sp. gr. 0'81 at 14. 
 
 ACETATE OF MANGANESE. Pale rose-coloured splinters or small prisms grouped to- 
 gether ; soluble in 3 pts. of water. 
 
 ACETATES OF MERCURY. Mercurous acetate, C 2 H 3 2 ,Hhg, [Hhg = Hg 2 = 200], is 
 obtained by precipitating mercurous nitrate with a soluble acetate. It forms anhydrous 
 micaceous laminae, sparingly soluble in water. Heat decomposes it into metallic mer- 
 cury, carbonic anhydride, and acetic acid. 
 
 Mercuric Acetate, C 2 H s 2 Hg [or C 4 H 3 3 .HgO], is prepared by dissolving red oxide 
 of mercury in warm acetic acid. It crystallises in brilliant micaceous laminae, soluble 
 in their own weight of water at 10, and somewhat more soluble in boiling water. 
 Alcohol and ether decompose it, separating mercuric oxide. 
 
 Acetate of Mercurammonium, OIPO*. (NH 3 Hg) + H 2 0, is obtained by agitating 
 recently precipitated mercuric oxide with a solution of acetate of ammonium. It crys- 
 tallises in rhomboi'dal plates, very soluble in water, insoluble in alcohol. At 100 it 
 gives off from 30 to 31 per cent, of its weight, and is converted into acetate of tetrar.ier- 
 curammonium, C 2 H 3 8 (NHg 4 ). 
 
 ACETATE OF NICKEL crystallises in apple-green prisms, slightly efflorescent, soluble 
 in 6 pts. of cold water, insoluble in alcohol. The solution is decomposed by hydro- 
 sulphuric acid, which throws down sulphide of nickel. 
 
 ACETATES OF POTASSIUM. Normal acetate. C 8 H 3 2 K [or C 4 H 3 3 .KO]. (Terra 
 foliata Tartari, Arcanum Tartari, Tartarus regeneratus, Bldttererde, gebldtterte 
 Weinsteinerde). 
 
 This salt exists in the juices of many plants. It is prepared by dissolving carbonate 
 of potassium in acetic acid. When brown vinegar is used for the purpose, the car- 
 bonate of potassium should be added by small portions, so as to keep the solution 
 constantly acid. The object of this precaution is to avoid the formation of coloured 
 products by the contact of free alkali with the foreign matters in the vinegar. Pure 
 acetate of potassium is a white salt, difficult to crystallise, very soluble in water and 
 deliquescent, soluble also in alcohol, and precipitated by ether from the alcoholic 
 solution. Carbonic acid gas, passed into a solution of the salt in absolute alcohol, 
 throws down carbonate of potassium, and liberates acetate of ethyl. The salt melts 
 below a red heat, forming a limpid oil, which solidifies in an extremely deliquescent 
 mass on cooling. It requires a very high temperature to decompose it, and then gives 
 off acetone, empyreumatic oil, and inflammable gases, and leaves a residue of carbonate 
 of potassium mixed with charcoal. Heated with excess of hydrate of potassium, it 
 yields carbonate of potassium and marsh gas : 
 
 C 2 H 3 2 K + KHO = CH 4 + C0 3 K 2 . 
 
 Heated with arsenious anhydride, it yields cacodyl. (See ARSENIDES OF METHYL.) Chlo- 
 rine, passed into the aqueous solution of acetate of potassium, liberates carbonic anhydride, 
 and forms a bleaching liquid, which however loses its decolorising power on exposure 
 to the air. When an electric current is passed through a strong aqueous solution of 
 acetate of potassium separated into two parts by a porous diaphragm, hydrogen alone 
 is evolved at the negative pole ; while, at the positive pole, there is evolved a gaseous 
 mixture of methyl and carbonic anhydride, together with acetate of methyl and a small 
 quantity of oxide of methyl. The principal decomposition is represented by the 
 equation : 
 
 C 2 H 4 2 = CH 3 + CO 2 + H, 
 
 the acetate and oxide of methyl being secondary products. (Kolbe, Ann. Ch. Pharm. 
 Ixix. 257.) 
 
 Acid Acetate or Diacctate of Potassium, C 3 H 3 0*K:.C 2 H 4 3 , [or C 4 If0 3 .HO + 
 
 When the normal acetate is evaporated with an excess of strong acetic acid, this 
 VOL. i. C 
 
IS ACETIC ACID. 
 
 acid salt is deposited in needles or laminae, or by slow evaporation in long flattened 
 prisms, apparently belonging to the rhombic system. It is very deliquescent, melts at 
 148, and decomposes at 200, giving off crystallisable acetic acid. On this property 
 is founded an easy method of obtaining the crystallisable acid. 
 
 Diacetate of potassium is formed when the nprmal acetate is distilled with butyric or 
 valerianic acid ; but neither of these acids decomposes the salt thus produced. Hence, 
 when butyric or valerianic acid is mixed with acetic acid, a separation more or less 
 complete may be effected by half neutralising the liquid with potash, and distilling. If 
 the acetic acid is in excess, diacetate of potassium alone remains behind, the whole of 
 the valerianic or butyric acid passing over, together with the remainder of the acetic 
 acid. If, on the contrary, the other acid is in excess, it passes over, unmixed with 
 acetic acid, and the residue consists of diacetate of potassium, mixed with butyrate or 
 valerate. By repeating the process a certain number of times, either on the acid 
 distillate or on the acid separated from the residue by distillation with sulphuric acid, 
 complete separation may be effected. (Liebig, Ann. Ch. Pharm. Ixxi. 355.) 
 
 Anhydrous Diacetate of Potassium, 2C 2 H 3 2 KC 4 H e 3 [ = KO. Z&IPO 3 ] is pro- 
 duced 'by dissolving melted acetate of potassium in acetic anhydride at the boiling 
 heat, or by the action of potassium on acetic anhydride. Forms colourless needles 
 very soluble in water, less deliquescent than normal acetate of potassium. It is de- 
 composed by heat, giving off acetic anhydride. (Gerhardt, Ann. Ch. Phys. [3] 
 xxxvii. 317.) 
 
 ACETATE OF SILVER, C 2 H 3 2 Ag. Obtained by precipitating nitrate of silver with 
 acetate of sodium. Crystallises from boiling water in thin, flexible laminae ; soluble 
 in 100 pts. of cold water. 
 
 ACETATE OF SODIUM, C 2 H s 2 Na [or C 4 H 3 9 .NaO.] Terra foliata tartari crystal- 
 lisabilis, Terre foliee miner ale. Prepared either by dissolving carbonate of so- 
 dium in acetic acid, or by decomposing acetate of calcium with sulphate of sodium. 
 Forms large transparent prisms belonging to the monoclinic system. Ordinary 
 combination: ooP.[oo Poo]. OP. P; more rarely with oo Poo, + P, + 2Poo. 
 Katio of the axes: a : b : c = 0-8348 :.l : 0-8407. Angle of the axes = 68 16'. In- 
 clination of the faces : oo P : oo P in the plane of the orthodiagonal and principal axis 
 = 95'30; P: +P, forming the obtuse edges of the pyramid +Pin the plane of 
 the oblique diagonal and principal axis = 117"32; ooP: OP = 75-35. Cleavage 
 parallel to OP and ooP. (Gerhardt, Traite i. 725.) The crystals contain 3 at. 
 water. They effloresce slightly in dry air, completely at a moderate heat, and melt 
 below 100. They dissolve in 3 -9 pts. of water at 6, in 2*4 pts. at 37, and in 
 1*7 pts. at 48 (Osann). According to Berzelius, a solution saturated at the boiling 
 heat, contains 0'48 pts. water to 1 pt. of salt, and boils at 124-4. The salt is less 
 soluble in alcohol. It has a bitter, pungent, but not disagreeable taste. 
 
 ACETATE OF STRONTIUM crystallises like the barium-salt in two different forms, con- 
 taining different quantities of water. The salt deposited at 15, contains 4-23 p. c. 
 water (? 4C 2 H 3 2 Sr + H 2 0), and that which is deposited at low temperatures con- 
 tains C 2 H 3 2 Sr + H 2 0. The latter forms prisms belonging to the monoclinic system, 
 oo P : oo P = 124 54' ; oo P . oo P oo =- 107 33' ; OP : P oo = 153-12. Cleavage 
 indistinct, parallel to ooPoo . 
 
 ACETATE OF TIN. Boiling acetic acid dissolves tin slowly, with evolution of hy- 
 drogen ; the hydrated protoxide dissolves easily in the boiling acid, and the solution 
 evaporated to a syrup and covered with alcohol yields small colourless crystals. Hy- 
 drated dioxide of tin also dissolves in acetic acid, and the solution yields a gummy 
 mass when evaporated. Bichloride of tin forms a crystalline compound with glacial 
 acetic acid. 
 
 ACETATE OF URANIUM. Uranous Acetate, obtained by evaporating a solution of 
 oxide in acetic acid, crystallises in green needles grouped in warty masses. 
 
 Uranic Acetate, or Acetate of Uranyl, C 2 H S 2 (U 2 0)* [ = W 3 <9 4 ./ 2 6> 2 ], is ob- 
 tained by heating uranic nitrate till it begins to evolve oxygen, dissolving the yellow- 
 ish red mass, which still contains nitric acid, in warm concentrated acetic acid, and 
 evaporating to the crystallising point ; all the nitric acid then remains in the mother 
 liquid. From a very concentrated, or from an acid solution slightly cooled, the salt 
 separates in beautiful rhomboi'dal prisms, C 2 H 8 2 (U 2 0) + H 2 0, belonging to the mo- 
 noclinic system ; boiling water decomposes them with separation of uranic hydrate, but 
 the solution yields the same crystals by evaporation. A more dilute solution cooled 
 below 10 deposits square-based octahedrons containing C 2 H 3 2 (U 2 0) + 1 H 2 0, or 
 
 * Uranyl, U 2 O, is a monatomic radicle/supposed to exist in the uranic compounds. ''See URANHM.) 
 
ACETIC ANHYDRIDE. 19 
 
 2C 2 H S 2 (U 2 0) 4- 3IFO. They give off | of their water at 200, and the rest at 275, 
 leaving the yellowish red anhydrous salt. 
 
 Uranic acetate combines with the acetates of the more basic metals, forming double 
 acetates. The ammonium, potassium, and sodium salts are obtained by adding the 
 solutions of the carbonates to a solution of uranic acetate, till a precipitate is formed 
 consisting of a uranate of the alkali-metal, redissolving this precipitate in a slight 
 excess of acetic acid, and cooling the solution till it crystallises. The other double 
 salts of this group are obtained by boiling the carbonates with uranic acetate, till the 
 whole of the uranic oxide is precipitated, redissolving the precipitate in acetic acid, 
 and evaporating. The lead and cadmium salts consist of 1 at. of uranic acetate combined 
 with 1 at. of the monobasic acetate, their formula being C 2 H 3 Pb0 2 . C 2 H 3 (U 2 0)0 2 
 + 3H 2 and C 2 H 3 Cd() 2 .C 2 H 3 (U 2 0)0 2 + f H 2 0. All the rest contain 2 at. uranic 
 acetate with 1 at. of the monobasic metal, their general formula being C 2 H 3 M0 2 . 
 2C 2 H 3 (U 2 0)0 2 + ftH 2 0. Most of these salts crystallise with facility, the potassium 
 and silver salts in the quadratic system ; the sodium salt forms regular tetrahedrons. 
 The strontium and calcium salts are very soluble in water, and difficult to crystallise. 
 The sodium salt is anhydrous ; the rest contain water of crystallisation. (Wertheim, 
 J. pr. Chem. xxix. 209; Weselsky, Chem. Gaz. 1858, 390.) 
 
 ACETATE or YTTRIUM, C 2 H 3 2 Y + H 2 0. Ehomboidal prisms with trihedral sum- 
 mits. They are permanent in the air at ordinary temperatures ; give off their water, 
 and become opaque at 100 ; dissolve in 9 pts. of cold water, and in a smaller quantity 
 of boiling water ; also in alcohol. (Berlin.) 
 
 ACETATE OF ZINC, C 2 H 3 2 Zn + |H 2 0, or 2C 2 H 3 2 Zn + 3H 2 [ = C*H 3 ZnO*+ 3HO], 
 Obtained by dissolving either the metal, the oxide, or the carbonate in acetic acid. 
 Crystallises in nacrtous efflorescent laminse belonging to the monoclinic system (Kopp's 
 Krystallographie, p. 310). Ordinary combination : OP. oo P. o> Poo . + P . + 2Pco , the 
 face OP predominating. ' a : b : c = 0-4838 : 1 : 0'87. Inclination of axes = 4630'. 
 Inclination of faces, oo P : oo P in the plane of orthodiagonal and principal axis = 
 112 36'; ooP.OP = 112 28'; OP: oo Poo =113 30' ; OP: Poo =80; OP: +P 
 = 75 30'. Cleavage parallel to OP. The salt dissolves very readily in water. At 
 100 it melts, gives off its water with a little acetic acid, then solidifies, and does not 
 liquefy again till heated to 190 or 195, at which temperature anhydrous acetate of zinc 
 sublimes in nacreous scales. At higher temperatures, complete decomposition ensues. 
 (Larocque, Eecueil des Trav. de la Soc. Pharm. 1847-54.) 
 
 ACETIC ACID, SUBSTITUTION* PRODUCTS OF. The following acids 
 (which will be more fully described hereafter), are derived from acetic acid by substi- 
 tution : 
 
 Brcmacetic acid C 2 H 2 BrO ) Q 
 
 H ) 
 
 Dibromacetic acid C 2 HBr 2 ) Q 
 
 H ) 
 
 Chloracetic acid ..... 
 
 Trichloracetic acid ^^Tll 
 
 * 
 
 lodacetic acid . . TT > 
 
 Diniod-acetic acid . . C *SJo 
 
 -CM 
 
 Thiacetic acid ..... 
 
 The brominated and chlorinated acids are produced by the direct action of bromine 
 and chlorine on acetic acid ; the iodated acids by the action of iodide of potassium on 
 bromacetate and dibromacetate of ethyl ; and thiacetic acid by treating glacial acetic 
 acid with pentasulphide of phosphorus (p. 11). All these acids are monatomic, 
 like acetic acid itself, correspond to it in nearly all their reactions, and are formed 
 upon the same type. 
 
 ACETIC ANHYDRIDE. C 4 H0 3 = (C 2 H 3 0)*0. Anhydrous Acetic acid; 
 Oxide of Acetyl; Acetate of Acetyl (Gerhardt, Traite, i. 711.) 
 
 This compound is obtained : 1. By the action of oxy chloride of phosphorus, POC1 3 , 
 on acetate of potassium. The acetate deprived of water by fusion, is introduced into 
 a tubulated retort, and the oxychloride of phosphorus admitted through the tubulus, 
 drop by drop. A violent action takes place, the mixture becoming very hot without 
 
 c 2 
 
20 ACETIC ANHYDRIDE. 
 
 the application of external heat, and a liquid distils over, which is the chloride of 
 acetyl, while tribasic phosphate of potassium remains in the retort : 
 3C 2 H 3 K0 2 + POC1 3 = P0 4 K 3 + 3(C 2 H 3 O.C1). 
 
 If now this liquid be poured back again three or four times into the retort, so that 
 it may remain for some time in contact with the acetate of potassium, that salt being 
 also in excess and pretty strongly heated, a further action takes place between the 
 acetate of potassium and the compound C 2 H 3 O.C1, the result of which is the forma- 
 tion of acetic anhydride : thus, 
 
 C 2 H 3 K0 8 + C 2 H 3 O.C1 = KC1 + C 4 H 6 3 . 
 
 The acetic anhydride enters into combination with the acetate of potassium, and a 
 considerable degree of heat is required to destroy this compound and cause the anhy- 
 dride to distil over. The distillate is more or less contaminated with acetic acid and 
 chloride of acetyl ; but on redistilling the crude product, these impurities pass over at 
 the commencement, before the temperature rises to 137'5, after which the pure 
 anhydride distils over. 2. By the action of terchloride of phosphorus on acetate of 
 potassium. When the liquid chloride is added drop by drop to the acetate of potas- 
 sium (about 1 pt. PCI 3 to more than 2 pts. of the acetate), the action begins without 
 application of heat, and chloride of acetyl, amounting in quantity to about half the 
 chloride of phosphorus used, distils over mixed with a small quantity of chloride of 
 phosphorus. On heating the residue after this action has ceased, acetic anhydride 
 distils over free from chloride, and in quantity equal to about a third of the chloride 
 of phosphorus used. The product contains a small quantity of a phosphorus-compound, 
 which causes it to impart a brownish colour to nitrate of silver ; but it may be freed 
 from this impurity by a second distillation with acetate of potassium. 3. By the 
 action of chloride of benzoyl, C 7 H 5 O.C1, on fused acetate of potassium. The first 
 products of the action are chloride of- potassium and acetate of benzoyl, C 9 H 8 3 : 
 
 C 7 H 5 0. Cl + C 2 H 3 K0 2 = KC1 + 0. 
 
 But if the acetate of potassium is in excess, and the mixture is heated somewhat 
 above the temperature at which the original substances act upon each other, a further 
 action takes place, and a colourless liquid distils over, which is acetic anhydride, while 
 benzoic anhydride remains in the retort in combination with benzoate of potassium. 
 These new products are formed by double decomposition between 2 atoms of the 
 benzoic acetate : 
 
 H5 U_ C'H 5 0) n C 2 H 3 0) n 
 |C 2 H 3 OJ U ~ C'H 5 OJ u + OTEPOJ" 
 
 4. By the action of chloride of acetyl, C 2 H 3 OC1, on dry benzoate of sodium. The reaction, 
 which takes place without the aid of heat, is precisely similar to the preceding. 
 
 Acetic anhydride is a colourless, very mobile, strongly refracting liquid, having a 
 powerful odour, similar to that of the hydrated acid, but stronger, and recalling at the 
 same time that of the flowers of the white-thorn. Sp. gr. 1-073 at 20 0> 5, which is 
 nearly that of the hydrated acid, O'H 4 2 + H 2 O, at its greatest density. Boiling 
 point 137'5 under a pressure of 750 mm. Vapour density = 3'47 (by calculation 3-531 
 for a condensation to 2 volumes). 
 
 Fuming sulphuric acid becomes heated by contact with acetic anhydride, carbonic an- 
 hydride being given off and a conjugated acid produced, which forms a gummy salt with 
 lead. Potassium acts violently on acetic anhydride,, evolving a gas which does not 
 take fire if the potassium be introduced by small portions at a time. The liquid, after 
 a while, solidifies into a mass of needles, consisting of a compound of acetic anhydride 
 with acetate of potassium (p. 33). An oily substance is also produced, having a very 
 pleasant ethereal odour. Finely divided zinc acts upon acetic anhydride in a similar 
 manner, but less energetically, and only when heated in the water bath ; hydrogen 
 gas is then given off, and a soluble salt formed, which is deposited in microscopic 
 crystals on the surface of the metal, and greatly retards the action. On saturating 
 the excess of acetic acid in the residue with carbonate of sodium, the ethereal 
 odour above mentioned is perceived. The hydrogen evolved, if collected immediately, 
 has the same odour, burns with a bluish flame, and the product of the combustion 
 renders lime-water turbid ; but after passing through potassium, it is inodorous, and 
 when burnt yields nothing but pure vapour of water. 
 
 Acetic anhydride does not combine immediately with water, but when poured into 
 that liquid, falls to the bottom in oily drops which dissolve after a while, if the liquid 
 is heated or agitated. It absorbs water from the air, and must therefore be kept in 
 well closed vessels. 
 
ACETIC ETHERS. 21 
 
 Acetic anhydride combines with aldehydes. With ordinary aldehyde, it forms a 
 liquid compound, C 4 H 6 3 . C 2 H 4 (Geuther), and a similar compound with valeral. 
 C'H 6 3 . C S H'0 (Guthrie and Kolbe) ; also with bitter almond oil (Geuther). 
 
 C 2 H 3 ) 
 ACETOBENZOIC, or BENZoACETic ANHYDRIDE, C 9 H 9 3 = r 0. Acetate of 
 
 Benzoyl, Benzoate of Acetyl. Obtained by the action of chloride of acetyl on benzoate 
 of sodium. Heavy oil smelling like Spanish wine. Neutral to litmus. Boils at 120 C. 
 and is resolved into acetic and benzoic anhydrides (p. 35). Besolved into acetic and 
 benzoic acids by boiling with water, and more quickly with alkalis. 
 
 ACETO-CINNAMIC ANHYDRIDE, C 2 H 3 O.C 9 H 7 0.0. Acetate of Cinnamyl, $c. A very 
 instable product obtained by the action of chloride of acetyl on cinnamate of sodium. 
 Oil heavier than water, something like the preceding compound. 
 
 ACETO-CUMINIC ANHYDRIDE, C-H 3 . C 10 H U . 0. Acetate of Cumyl. Eesembles 
 the preceding compounds. In the moist state it quickly turns acid, and yields beautiful 
 laminae of cuminic acid, the odour of acetic acid becoming perceptible at the same time. 
 
 ACETO-SALICYLIC ANHYDRIDE, C 2 H 3 . C 7 H 5 2 .0. Acetate of Salicyl, $c. Salicylate 
 of sodium is strongly attacked by chloride of acetyl, even at ordinary temperatures, 
 the mixture liquefying at first, but becoming perfectly hard in a few seconds. The 
 product dissolves with effervescence in carbonate of sodium, the anhydride being con- 
 verted into acetate and salicylate of sodium. (G-erhardt, Traite, iii. 319.) 
 
 ACETIC ETHERS. These compounds are the acetates of the alcohol-radicles, 
 and may be divided into the following groups : 
 1. IMtonatomic Acetic Ethers. 
 
 ACETATE OF ALLYL, C-H 3 O.C 3 H 5 . Prepared by treating acetate of silver with iodid 
 of allyl, and rectifying once or twice over acetate of silver. It is a colourless liquid, 
 lighter than water, having a pungent, aromatic odour, and boiling between 98 and 
 100. Boiling potash decomposes it into acetate of potassium and allyl-alcohol. 
 (Cahours and Hofmann, Chem. Soc. Qu. J. x. 322.) 
 
 ACETATE OF AMYL, or ACETATE OF PENTYL, C 2 H 3 2 .C 5 H H . This compound is 
 slowly produced when amylic alcohol is left in contact with acetic" acid, and may be 
 conveniently prepared by distilling 2 pts. of acetate of potassium, or 3 pts. of de- 
 hydrated acetate of lead, with 1 pt. of strong sulphuric acid, and 1 pt. of amylic 
 alcohol, agitating the distillate with milk of lime, then dehydrating over chloride of 
 cnlcitim, and rectifying. It is a transparent, colourless liquid, of sp. gr. 0-8572 at 21, 
 and boiling a't 133'3, under a pressure of 27" 8'", with a platinum wire immersed in 
 it. Vapour-density 4'458. Odour ethereal and aromatic, like that of acetate of 
 ethyl. It is insoluble in water, but dissolves in alcohol, ether, and fusel oil. It is 
 decomposed very slowly by aqueous potash, but quickly by alcoholic potash, yielding 
 amylic alcohol and acetate of potassium. Chlorine passed through it at 100, converts 
 it into di-chlorinatcd acetate of a my I, C 7 H I2 C1 2 0'-, and this, by the action of chlorine in 
 sunshine, is converted into a higher chlorine-compound. 
 
 ACETATE OF BENZYL, C 2 H 3 2 .C 7 H 7 . Produced by treating 2 vol. benzyl-alcohol with 
 a mixture of 1 vol. sulphuric acid and 4 or 5 vol. acetic acid, or by boiling chloride of 
 benzyl with alcoholic acetate of potassium. Colourless oil, heavier than water, and 
 having a very agreeable odour, like that of pears. Boils at 210 C. Boiled with 
 potash-ley, it yields acetate of potassium and benzylic alcohol. (Cannizzaro, Ann. 
 Ch. Pharm. Ixxxviii. 130.) 
 
 ACETATE OF ETHYL. Acetic ether, Etht/lic Acetate, Essigdther, Essignaphtha, Es- 
 sff/aaiires Mthyloxyd, Ether acetique. C 4 H 8 2 = C-H 3 2 .C 8 H 5 . or CWO^CWO. 
 (Lauragais, Journ. d. S9avans, 1759, 324; Thenard, Mem. d'Arcueil, i. 153; 
 Dumas andBoullay, J. Pharm. xiv. 113; Liebig, Ann. Ch. Pharm. v. 34; xxx. 
 144 ; Gm. viii. 493 ; Gerh. i. 743). Discovered by Lauragais in 1759. It is formed 
 by heating alcohol with acetic acid, or with an acetate and strong sulphuric acid, 
 or by distilling ethyl-sulphate of calcium or potassium with glacial acetic acid. The 
 best mode of preparing it is to distil a mixture of 3 pts. of acetate of potassium, 
 3 pts. of absolute alcohol, and 2 pts. of sulphuric acid; or 10 pts. of acetate of sodium, 
 6 pts. of alcohol, and 15 pts. of sulphuric acid; or 16 pts. of dry acetate of lead, 
 4^ pts. of alcohol, and 6 pts. of sulphuric acid. The acid is first mixed with the 
 alcohol, and the liquid poured upon the salt reduced to fine powder. The mixture is 
 then distilled to dry ness, the heat being moderate at first, but increased towards the 
 end of the process. The product is purified by digesting it with chloride of calcium 
 and rectifying the decanted liquid. 
 
 c 3 
 
22 ACETIC ETHERS. 
 
 Acetate of ethyl is a colourless liquid, baying a pleasant ethereal odour. Sp. gr. 
 0-91046 at (Kopp); 0*932 at 20 (Gossmann). Boils at 74 0> 3, when the barometer 
 stands at 760mm. (Kopp). Vapour-density 3 '06 (Boullay and Dumas). It dis- 
 solves in 11 or 12 pts. of water, at ordinary temperatures (Mohr, Arch. Pharm.[2] Ixv. 1), 
 in all proportions of alcohol and ether. It burns with a yellowish flame, giving off the 
 odour of acetic acid, and leaving that acid in the liquid state. It is permanent when 
 dry, but in the moist state gradually decomposes into alcohol and acetic acid. The same 
 decomposition takes place more quickly under the influence of alkalis. Heated with 
 strong sulphuric acid, it is resolved into oxide of ethyl and acetic acid. Hydro- 
 chloric acid converts it into acetic acid and chloride of ethyl. 
 
 Action of Chlorine on Acetate of Ethyl. (Malaguti, Ann. Ch. Phys. [2] xx. 
 367; ibid. [3] xvi. 2, 58; Leblanc, ibid. [3] 197; Cloez, ibid. [3] xvii. 304., 
 When acetate of ethyl is introduced into a bottle filled with dry chlorine gas, in the 
 proportion of 1 atom acetate of ethyl to 8 atoms chlorine, and the action allowed to 
 go on, first in the shade and afterwards with continually greater exposure to sunshine, 
 a number of chlorinated compounds are formed in which 2, 3, 4, 5, 6, 7, and 8 atoms 
 of hydrogen in the acetate of ethyl are successively replaced by an equal number of 
 chlorine-atoms. It is however not always possible to obtain the particular compound 
 required, the compounds C 4 H 6 C1-0 2 , C 4 HC1 7 0-, and C 4 C1 8 2 , being the only ones that 
 can be produced with certainty. Other products are also formed, among which are 
 acetic acid, trichloracetic acid, and sesquichloride of carbon. If the acetate of 
 ethyl is at once exposed to sunshine in contact with chlorine, an explosion takes place, 
 attended with deposition of charcoal. 
 
 Dichlorinated Acetate of Ethyl, C 4 H 6 C1 2 2 , is the product obtained when the acetate 
 of ethyl is kept cool and in the shade during the action of the chlorine. On distilling 
 the product to separate the more volatile portions, till the boiling point rises to 110, 
 washing the brownish residue with water, and drying it over lime and sulphuric acid, 
 the compound is obtained as a transparent colourless oil, of sp. gr. 1-301 at 12. It 
 smells somewhat like acetic acid, has a peppery taste, and produces irritation in the 
 throat. It is slowly decomposed by water, yielding hydrochloric and acetic acids. 
 C 4 H G C1 2 2 + 2^0 = 2C 2 H 4 2 + 2HC1; slowly also by aqueous potash, but quickly by 
 alcoholic potash, yielding acetate and chloride of potassium. (Malaguti.) 
 
 Trichlorinated 'Acetate of Ethyl, C 4 H 5 C1 3 0", was obtained by exposing the di- 
 chlorinated compound for some time to the action of chlorine in a bottle, covered at the 
 upper part with black paper, so that the light fell only on the lower part of the liquid. 
 It resembles the preceding compound, but cannot be distilled without alteration. It 
 is isomeric with trichloracetate of ethyl, C-CP0 2 .C-H 5 . See TRICHLOKACETIC ACID. 
 (Leblanc.) 
 
 Tetrachlorinated Acetate of Ethyl, C 4 H 4 C1 4 0' ? , was obtained by exposing the di- 
 chlorinated compound to the sun in autumn, in bottles filled with dry chlorine. After 
 rectification, washing, and drying, it forms an oil of sp. gr. 1-485 at 25. It is de- 
 composed by potash, yielding chloride, acetate, and trichloracetate of potassium 
 (Leblanc). The five-chlorine compound, C 4 H 3 CP0 2 , was obtained in the same 
 manner as the preceding, excepting that the gas above the liquid was protected from 
 the action of the solar rays ; the six-chlorine compound C 4 H 2 C1 8 C 2 , by exposing the 
 last compound to the sun for two days, in a bottle filled with dry chlorine. Sp. gr. 
 1-698 at 23-5. The seven-chlorine compound, C 4 H01 7 C 2 , was produced by exposing the 
 dichlorinated compound in bottles filled with dry chlorine, to the sun for some months 
 in winter. It forms rather soft crystals, insoluble in water, sparingly soluble in cold 
 alcohol of ordinary strength, very soluble in ether. They melt ^elow 100, but do not 
 appear to be volatile without decomposition. An oily liquid isomeric with this com- 
 pound, and having a sp. gr. of T692 at 24-5, is obtained by exposing trichloracetate 
 of ethyl to chlorine in the shade, as long as any action goes on. (Leblanc.) 
 
 Perchlorinated Acetate of Ethyl, C 4 C1 8 2 , is prepared by exposing di- or tri-chlori- 
 nated acetate of ethyl to the brightest summer sunshine, and at the same time heating 
 it to 110; even then the substitution takes place very slowly (Leblanc). The pro- 
 duct is distilled in an atmosphere of carbonic acid, to remove free chlorine. It is a 
 colourless oil, which remains liquid at a few degrees below 0, and has a strong pungent 
 odour like that of chloral. Sp. gr. 1*79 at 25. Boils, with partial decomposition, at 
 245 (Leblanc). When its vapour is passed through a tube filled with fragments of 
 glass, and heated to 400, it is partly converted into the isomeric compound chlor- 
 aldehyde, C 2 C1 4 O (Malaguti). In contact with water or moist air, it is gradually 
 decomposed, yielding trichloracetic and hydrochloric acids. A similar decomposition 
 is instantly produced by strong aqueous potash (Leblanc) : 
 C 4 C1 8 0* + 2H 2 = 2C 2 IIC1 3 2 
 
ACETIC ETHERS. 23 
 
 Ammonia, either gaseous or dissolved in water, acts strongly on the compound, pro- 
 ducing sal-ammoniac and trichloracetamide(Malaguti) : 
 
 C 4 C1 8 2 + 2NH 3 = 2HC1 + 2C 2 IFC1 3 NO 
 
 With absolute alcohol, the compound becomes strongly heated, and is completely con- 
 verted into hydrochloric acid and trichloracetate of ethyl (Malaguti) : 
 
 OCPO 2 + 2C 2 H 6 = 2HC1 + 2C 4 H*C1 3 2 . 
 
 When exposed for a long time to the action of chlorine, it yields crystals of sesqui- 
 chloride of carbon. (Leblanc.) 
 
 Perchloracetic ether may be regarded as a trichloracetate of pentachlorethyl, 
 C 2 C1 3 2 . C 2 C1 5 ; and in like manner, all the preceding compounds which contain more than 
 3 atoms of chlorine, may be viewed as trichloraeetates of ethyl-radicles, in which the H 
 is more or less replaced by Cl: e.g. pentachloracetic ether, C 2 H 3 C1 5 O 2 = C 2 C1 3 2 .C 2 H 3 CF. 
 Some of them appear however to be susceptible of isomeric modifications. 
 
 ACETATE OF METHYL, C^O 2 = C 2 H 3 . CH 3 . Methylic Acetate, Essigsaurer 
 Holzdther. (Dumas and Peligot (1835), Ann. Ch. Phy's. Iviii. 46. Weidmann 
 and Schweizer, Pogg. xliii. 593. H. Kopp, Ann. Ch. Pharm. Iv. 181. Grm. viii. 
 484; G-erh. i. 741.) This compound occurs in crude wood-vinegar (Weidmann and 
 Schweizer). The liquid called Mother lignosus or Spirit us pyroaceticus appears to be 
 impure acetate of methyl. 
 
 Preparation. 1. Two pts. of wood-spirit are distilled with 1 pt. of glacial acetic 
 acid and 1 pt. sulphuric acid ; the distillate is shaken up with chloride of calcium, 
 the acetate "of methyl then rising to the top ; and this product is freed from sul- 
 phurous acid by agitation with quicklime, and from wood- spirit by 24 hours' contact 
 with chloride of calcium, which takes up the latter substance (Dumas and Peligot). 
 2. When 1 part of wood-spirit is distilled with 1 pt. acetate of potassium and 
 2 pts. of sulphuric acid, acetate of methyl passes over first, then sulphurous acid, acetic 
 acid, methylic oxide, and a small quantity of methylic sulphate. The first receiver 
 must therefore be removed as soon as sulphurous acid begins to escape ; its contents 
 shaken up with water ; and the separated ether rectified over chloride of calcium and 
 quicklime (Weidmann and Schweizer). 3. A mixture of 3 pts. wood-spirit, 14^ 
 pts. dehydrated acetate of lead, and 5 pts. sulphuric acid is distilled ; the distillate 
 is shaken up with milk of lime ; and the stratum of methylic acetate which rises to the 
 surface is dehydrated by repeated treatment with chloride of calcium, then decanted 
 from the lower liquid, and rectified. (H. Kopp.) 
 
 Acetate of methyl is a colourless liquid, having a very agreeable odour, like that 
 of acetate of ethyl, sp. gr. 9-0085 at 21; 0-9562 at (Kopp). Boiling point, 56-3 
 under a pressure of 760 mm. (Kopp, Pogg. Ann. Ixii. 1); 55 under a pressure of 
 762mm. (Andrews, Chem. Soc. Qu. J. i. 27). Vapour-density 2"563 (Dumas and 
 Peligot), by calculation 2-564. Index of refraction 1-3576. (Delffs, Pogg. Ann. 
 Ixxxi. 470.) 
 
 Acetate of methyl dissolves in water, and mixes in all proportions with alcohol and 
 ether. The aqueous solution suffers but little decomposition by boiling. Solutions of 
 caustic alkalis convert the compound into wood-spirit and an alkaline acetate. When 
 poured on pulverised soda-lime, it is decomposed with violence, yielding a mixture of 
 acetate and formate of sodium, and giving off h}'drogen. In contact with strong sul- 
 phuric acid, it becomes heated, gives off acetic acid, and forms methylsulphuric acid. 
 With chlorine it forms a number of substitution-products. 
 
 Dichlorinated Acetate of Methyl, C 3 H 4 C1-O 2 , is formed by passing dry chlorine gas 
 through acetate of methyl, assisting the action by a gentle heat towards the end. It 
 is purified like the corresponding ethyl-compound. It is a colourless neutral liquid, 
 having a pungent odour ; its taste is sweet at first, but afterwards alliaceous and burning. 
 Sp. gr. 1*25. Boils between 145 and 148, but begins to decompose and give off 
 fumes at 138. It burns with a yellow flame, edged with green at the bottom. It is 
 decomposed slowly by water, quickly by aqueous potash, and violently by alcoholic 
 potash, yielding formic, acetic, and hydrochloric acids : 
 
 C 3 H 4 C1 2 2 + 2H O = CIPO 2 - C 2 H 4 8 + 2IIC1. 
 
 This compound is isomeric if not identical with dichlorinated formate of ethyl. 
 (Malaguti, Ann. Ch. Phys. [2] Ixx. 379.) 
 
 Trichlorinated Acetate of Methyl, C 3 H 3 C1 3 2 , is obtained by passing chlorine very 
 slowly into acetate of methyl, as long as any decomposition takes place, and purifying 
 the product by repeated fractional distillation. It is a colourless oily liquid, heavier 
 than water, boiling at 145, and distilling without decomposition. It is decomposed by 
 caustic potash, yielding chloride and formate of potassium, and chloromethylase, CHC1 : 
 
 C 3 H 3 C1 3 2 + 2K 2 = 2KC1 + 2CHKO 2 + CHC1. 
 c 4 
 
21 ACETIC ETHERS. 
 
 It is isomerlc but not, identical with trichloracetate of methyl, C C1 3 8 . CH S , produced 
 by distilling wood-spirit with trichloracetic acid and a small quantity of sulphuric 
 acid. (Laurent, Ann. Ch. Phys. [2] Ixxiii. 25.) 
 
 Perchhrinated Acetate of Methyl, C S C1 6 2 . (Cloez, Ann. Ch. Phys. [3] xvii. 297, 
 311.) This compound, which appears to be identical with perchlorinated formate 
 of ethyl, is produced by exposing acetate of methyl to the action of chlorine in 
 sunshine, as long as the gas continues to be absorbed. It is a colourless liquid, having 
 a suffocating odour and a disagreeable taste, which soon becomes intolerably acid, from 
 decomposition. Sp. gr. 1'705 at 18. Boils at about 200, with partial decomposition. 
 It is quickly decomposed by water and by moist air, yielding hydrochloric, carbonic, and 
 terchloracetic acids : 
 
 C 3 C1 6 2 + 2H 2 = 3HC1 + CO 2 + C 2 HCP0 2 . 
 
 Similarly by the fixed alkalis in solution. With aqueous ammonia, it forms tri- 
 chloracetamide, together with chloride and carbonate of ammonium : 
 
 C 3 C1 6 2 + 6NH + 2H 2 = KH 2 .C 2 C1 3 + 3NH 4 C1 + CO 3 (NH 4 ). 2 
 
 With alcohol it forms hydrochloric acid, trichloracetate of ethyl, and monochlori- 
 nated fonniate of methyl : 
 
 C 2 C1 6 2 + 2C 2 H"0 = 2HC1 + C 8 C1 3 2 .C 2 H 5 + C 2 H S C10 2 . 
 
 Similarly with wood-spirit it yields trichloracetate of methyl, and monochlorinated 
 formate of methyl. 
 
 The vapour passed through a red-hot porcelain tube is decomposed into chloraldehyde 
 and chloro-carbonic oxide (phosgene) gas: 
 
 C 8 C1'0 2 = C 2 C1 4 + COC1 2 . 
 
 ACETATE OF OCTYL, C 2 H 3 2 . C 8 H 17 . Prepared by passing hydrochloric acid gas 
 through a mixture of acetic acid and octylic (caprylic) alcohol ; or, better by dis- 
 tilling a mixture of octylic alcohol, acetate of sodium, and sulphuric acid. It is a 
 liquid of very agreeable odour, insoluble in water, boiling at 1 90. (B o u i s, Compt. rend, 
 xxxviii. 937.) 
 
 ACETATE OF PHENYL, C 2 H 3 O.C 6 H 5 . Produced by the action of chloride of acetyl 
 on acetate of phenyl : also by boiling an alcoholic solution of phosphate of phenyl 
 with acetate of potassium. After all the alcohol has evaporated, the temperature of the 
 mixture rises rapidly, and acetate of phenyl distils over in the form of an oily liquid. 
 It is heavier than water, and slightly soluble in that liquid. Boils at 190. Boiling 
 potash decomposes it, yielding acetate of potassium and hydrate of phenyl. (S c r u g h a m, 
 Chem. Soc. Qu. J. vii. 241.) 
 
 ACETATE OF TETRYL, or ACETATE OF BUTYL, C 2 H 3 2 . C 4 H 9 . Obtained by heating 
 iodide of tetryl with a slight excess of very dry acetate of silver in a sealed flask 
 at 100: also by distilling in an oil-bath equivalent quantities of acetate of po- 
 tassium (recently fused) and tetryl-sulphate of potassium : 
 
 C 2 H 3 2 .K + S0 4 .K.C 4 H 9 = C 2 H 8 2 .C 4 H 9 + S0 4 .K 9 
 
 ACETATE OF TRITYL, or ACETATE OF PROPYL, C 2 H 3 2 .C 3 H 7 . Obtained by distilling 
 propylic alcohol with a mixture of acetic and sulphuric acid. Eesembles acetate of 
 ethyl. Boils at 90. (Berthelot.) 
 
 It is a colourless liquid of agreeable odour. Sp. gr. 0-8845 at 16 C. Boils at 
 114. Vapour-density 4*073 (calculation, 4-017). Boiling potash converts it into 
 acetate of potassium and tetrylic alcohol. 
 
 2. Diatomic Acetic Etbers. (Grlycolic Ethers.} These compounds are derived 
 from the diatomic alcohols or glycols by the substitution of 1 or 2 at. acetyl (C 2 H 3 = Ac), 
 for 1 or 2 at hydrogen. They are related to the glycols in the same manner as the 
 monatomic acetic ethers just described are related to the monatomic alcohols. The 
 following have been obtained : 
 
 Monoacetate of Ethylene ^c H 
 
 Diacetate of Ethylene ^jffl' \ 2 
 
 Diacetate of Propylene ^S / ' f O 2 
 
 Ac 2 
 Diacetate of Benzylene ?" I'' [ 2 
 
 The diacetates are produced by the action of acetate of silver on the chlorides, 
 bromides, or iodides of the several diatomic alcohol-radicles : e. g. 
 
 Diacetate of Butylene 
 
 Diacetate of Amylene (C 5 H 10 )" J Q2 
 
ACETINS. 25 
 
 Bromide of 2 at. acetate of Diacetate of 
 
 ethylene. silver. ethylene. 
 
 Monoacetate of ethylene is obtained by heating acetate of potassium with an alco- 
 holic solution of bromide or chloride of ethylene, or by heating in a sealed tube a 
 mixture of 1 at. hydrate of ethylene and 1 at. acetic anhydride : 
 
 All these compounds when distilled with potash are converted into the corre- 
 sponding diatomic alcohols. They will be more fully described in connection with 
 these several alcohols. 
 
 3. Tri atomic Acetic Ethers; Acetins. (Berth elot, Ann. Ch. Phys. [3] 
 xli. 277; Gin. ix. 496 ; G-erh. iii. 950; Berthelot and De Luca, Ann. Ch. Phys. 
 [3] liii. 433). Compounds obtained by the union of 1 at. glycerin, C 3 H 8 3 , with 1, 
 2, or 3 at. acetic acid C 2 H 4 2 , with elimination of an equal number of atoms of water. 
 They may be regarded as glycerin, C 3 H 5 S .H 3 , in which 1, 2, or 3 at. hydrogen are 
 replaced by acetyl. 
 
 Monoacetin, C 5 H 10 4 = C 8 H 5 3 .H 2 .C 2 H 3 0, is produced by heating a mixture of 
 glycerin and glacial acetic acid to 100 for 24 hours. Slight traces are also formed 
 by mere contact of the liquids at ordinary temperatures. It is a neutral liquid, having 
 a slightly ethereal odour. Sp. gr. 1/20. Mixed with half its bulk of water, it forms a 
 clear liquid, which becomes turbid on the addition of two or more volumes of water; 
 but the acetin does not separate from it, and the emulsion continues opalescent even 
 after the addition of a large quantity of water. Treated with alcohol and hydrochloric 
 acid, it forms glycerin and acetate of ethyl. It mixes with ether. 
 
 Diaeetin, also called Acetidin, C 7 H 12 5 = C 3 H 5 3 .H.(C 2 H 3 0) 2 = C 3 H S 3 + 2C 2 H 4 2 
 2H'-'0, is obtained by heating glacial acetic acid with excess of glycerin to 200 for 
 3 hours ; by heating the same two liquids together at 275 ; by heating glycerin to 
 200 with acetic acid diluted with an equal bulk of water ; and by heating to 200 a 
 mixture of 1 pt. of glycerin with 4 or 5 pts. of acetic acid. It is a neutral odori- 
 ferous liquid having a sharp taste; sp. gr. about 1*85. Boils at 280, and distils with- 
 out alteration. Assumes a viscid consistency at 40. It becomes slightly acid by 
 prolonged contact with air. 100 pts. of it saponified with baryta, yield 52*4 pts. of 
 glycerin and a quantity of acetate of barium corresponding to 66 -4 pts. of acetic acid ; 
 calculation requires 52'3 glycerin and 68'2 acetic acid. "With alcohol and hydro- 
 chloric acid it yields glycerin and acetate of ethyl. It dissolves in ether and in benzol. 
 
 Triacetin, C 9 H 14 6 = C 3 H 5 3 .(C 2 H 3 0) 3 = C 3 H 8 3 + 3C 2 H 4 - 3 H 8 0. Obtained 
 by heating diacetin to 250 for 3 hours with 15 to 20 times its weight of glacial 
 acetic acid. Eesembles the preceding compound. Sp. gr. 1-174 at 8. Volatilises 
 without residue. 100 pts. saponified with baryta yielded 80 '6 pts. acetic acid, and 
 43'1 glycerin; by calculation it should be 82*6 acetic acid and 42'2 glycerin. It is 
 insoluble in water, but soluble in dilute alcohol. 
 
 A compound of acetic acid and glycerin, probably triacetin, appears to exist in cod- 
 liver oil (De Jongh, Berz. Jahresber. 1843), and in considerable quantity in the oil 
 obtained from the seeds of Euonymus europcsus (Schweizer, J. pr. Chem. liii. 437). 
 Acetic acid was also observed by Chevreul among the product of the saponification of 
 fats. 
 
 Aeetochlorhydrin, C 5 H 9 C10 3 = C 3 H 9 3 -i- C 2 H 4 2 + HC1 - 2H 2 0, is obtained by 
 passing hydrochloric acid gas to saturation into a mixture of acetic acid and glycerin 
 heated to 100, and saturating the liquid with carbonate of sodium, after leaving it 
 at rest for several days. This process yields the compound mixed with dichlorhydrin. 
 It is also obtained, together with the following compound, by the action of chloride 
 of acetyl on glycerin. It is a neutral oil, smelling like acetate of ethyl and volatilising 
 at about 250. 
 
 Acetodicklorkydrin,C 5 IL 8 Cl 2 2 = C 3 H S 3 + C 2 H 4 2 + 2HC1 - 3H 2 0, is obtained by 
 adding chloride of acetyl to glycerin externally cooled, as long as any action takes 
 place, distilling the product, and purifying the distillate obtained between 180 and 
 160, by agitation with water and then with an alkali, drying with chloride of cal- 
 cium and quicklime, and fractional rectification. It is a transparent neutral oil 
 having a refreshing ethereal odour, sparingly soluble in water and distilling at 205 
 without decomposition. (Berthelot and De Luca.) 
 
 Diaci'tochlorht/drin, C'HC10 4 = C 3 H 8 3 + 2C 2 H 4 2 + IIC1 - 3H 2 0, is obtained 
 by the action of chloride of acetyl on a mixture of equal volumes of glycerin and 
 
26 ACETINS ACETONE. 
 
 glacial acetic acid. It is a neutral liquid which volatilises at 245. (Berthelot and 
 De Luc a.) 
 
 Similar compounds are produced by the action of bromide of acetyl on glycerin. 
 By treating glycerin with a mixture of chloride and bromide of acetyl in equal numbers 
 of atoms, acetochlorbromhydrin, C 5 H 8 ClBr0 2 = C 3 H 8 3 + C 2 H 4 2 " + HC1 + HBr - 
 3 IPO, is obtained as a neutral colourless liquid, smelling like acetate of ethyl and 
 bromide of ethylene, boiling at 208, and distilling without decomposition. It is 
 somewhat coloured by exposure to light. (Berthelot and D e L u c a. ) 
 The formulae of all these compounds may be derived from that of a triple molecule 
 
 HHO 
 
 of water HHO. By replacing 3 at. hydrogen in this formula by the triatomic 
 HHO 
 
 H 
 
 radicle, glyceryl C 3 H 5 , we obtain glycerin H(C 3 H 5 )0. Keplacing 1, 2 or 3 at. II in 
 
 H 
 
 this formula by acetyl (C 2 H S = Ac), we obtain monoacetin, &c. ; and, lastly, the re- 
 placement of one or two molecules of peroxide of hydrogen (HO), by chlorine in the 
 formulae of monoacetin and diacetin gives the acetochlorhydrins. Thus : 
 
 H 
 
 Monacetin. . . . Ac(C 8 H)'"0 
 H 
 
 H 
 
 Acetochlorhydrin . . Ac(C 3 H 5 ) /// 
 
 Cl 
 Cl 
 
 Acetodichlorhydrin . . Ac(C 3 H 5 )'"0 
 
 Br 
 Acetochlorbromhydrin . Ac (C"H'y"0 
 
 Cl 
 
 Ac O 
 
 Diacetochlorhydrin . . Ac(C 3 H 5 )'"0 
 
 Cl 
 
 Triacetin .... Ac 3 (C 8 H 5 ) /// 0". 
 
 Cl 
 
 ACETXTE. A compound formed from acetic acid and mannite in the same manner 
 as acetin from acetic acid and glycerin. (Berthelot, Compt. rend, xxxviii. 668.) 
 
 ACETO1WETER. A hydrometer graduated for determining the strength of com- 
 mercial acetic acid according to its density. (See ACETIC ACID.) 
 
 ACETONE. C 3 H 6 = C 2 H 3 O.CH 3 [or C*H H 0*]. Pyroacetic spirit, Essiygcist, 
 Brenzessiggeist (Gm. ix. 1 ; xiii. 462; Gerh. i. 700; iii. 943 ; iv.906). This compound 
 has long been known as a product of the destructive distillation of acetates (p. 2S). It is 
 also produced by passing the vapour of acetic acid through a red-hot tube ; by heating 
 gnm, sugar, tartaric acid, citric acid and other vegetable substances in contact with 
 lime ; and by heating citric acid with permaganate of potassium, or with a mixture of 
 binoxide of manganese and dilute sulphuric acid. (Pean de St. Gilles, Compt. 
 rend, xlvii. 555.) 
 
 C 6 H 8 7 + = C 3 H 6 + 3C0 2 + H 2 0. 
 
 Citric acid. 
 
 It is prepared : 1. By distilling acetate of barium or acetate of calcium at a mode- 
 rate heat, the metal then remaining in the form of carbonate : 
 2C 2 H 3 Ba0 2 = C 3 H 6 + C0 3 Ba 2 . 
 
 Acetate of barium when dry and pure, yields a perfectly colourless neutral distillate, 
 in fact pure acetone. The calcium-salt requires a higher temperature to decompose it, 
 and the distillate is in consequence contaminated with an empyreumatic oil, called 
 dumasin, C 10 H 16 0. 2. By distilling in an iron retort or quicksilver bottle, a mixture 
 of 2 pts. of acetate of lead and 1 pt. of pounded quicklime, rectifying the product 
 several times over chloride of calcium, and finally distilling over the water-bath. 
 
 Acetone is a limpid, very mobile liquid, of sp. gr. 0*792 at 18 (Liebig), 0-814 at 
 (H. Kopp). Itdoes not solidify at 15. Boils at 56 (Dumas), at 56-3 (Kopp) 
 under a pressure of 760 mm. Evaporates quickly, producing a considerable degree 
 of cold. Vapour-density 2'002o (D urn as). It has un agreeable odour, and a biting 
 taste like that of peppermint. It is very inflammable, and burns with a white flame, 
 without smoke. 
 
 Acetone mixes in all proportions with water, alcohol, ether, and many compound 
 ethers. It does not dissolve potash or chloride of calcium. It dissolves many cam- 
 phors, fats and resins. 
 
 Acetone forms definite compounds with the alkaline bisulphites. The potassium 
 salt, C 3 H 6 + SO 3 (KH), and the sodium-salt, C 3 H0 + S0 3 (NaH) crystallise in 
 nacreous scales (Limpricht). The ammonium-salt, C 3 H S + SO* (NH 4 H,) is de- 
 posited on mixing an alcoholic solution of bisulphite of ammonium with acetone, in 
 
ACETONE. 27 
 
 laminae resembling cholesterin, which quickly aggregate into a heavy crystalline 
 powder. (Stadeler.) 
 
 Acetone was regarded by Kane as an alcohol, C 3 H 5 .H.O, containing the radicle C 3 H 5 , 
 which he called mesityl. According to this view, however, the oxidation of acetone 
 should yield products containing C 3 , just as the oxidation of common alcohol, C 2 H 6 
 yields aldehyde and acetic acid containing C 2 ; but no such products are obtained. 
 A more probable view of the composition of acetone is that of Chancel, who regards it 
 as aldehyde coupled with methylene, C 2 H 4 O.CH 2 , or, which comes to the same thing, 
 that of G-erhardt and Williamson, who regard it as aldehyde in which the basic hy- 
 
 drogen is replaced by methyl; jp f This view is quite in accordance with the 
 
 decomposition of acetates into acetone and carbonates. For acetyl may be regarded as 
 a compound of methyl with carbonic oxide ; [C 2 H 3 = CH 3 . CO.] ; and it is easy 
 
 to conceive that 2 atoms of acetate of barium ~' 0, may decompose in such 
 
 a manner that the CO of the one may unite with the two atoms of barium and 
 the two external atoms of oxygen, to form carbonate of barium, while the methyl 
 remains in combination with the other atom of acetyl, forming acetone : 
 
 /CH 3 .CO> \ _ CO) Q2 CH 3 .CO) 
 M Ba ) "" Ba 2 { CH 3 1 
 
 Acetate of barium. Carbonate Acetone. 
 
 of barium. 
 
 The same view is strengthened by the fact (discovered by Williamson) that when a 
 mixture of acetate and valerate of barium is heated, an acetone is formed containing 
 acetyl coupled with tetryl (C 4 H 9 ), or valyl (C 5 H 9 0) with methyl: thus 
 CH 3 .CO ) n C 4 H 9 .CO ) n CO ) n . C 2 H 3 ) 
 Ba \ + Ba \ = Ba 2 j + CTP { 
 
 Decompositions of Acetone. 1. Acetone passed in the state of vapour through a red- 
 hot tube, deposits charcoal and is converted into a peculiar oil called dumasin, which 
 generally passes over together with acetone in the distillation of acetates. 
 
 2. Acetone is decomposed by chlorine, a portion of its hydrogen being replaced by 
 that element ; but it is not possible in this manner to replace the whole of the hydro- 
 gen by chlorine; even a mixture of chlorate of potassium and hydrochloric acid does 
 not appear to be capable of replacing more than two of the hydrogen atoms by chlorine. 
 The higher chlorinated acetones, may however be obtained by the action of chlorine, 
 or the mixture just mentioned, on other organic bodies. (See CHLOKACETONES, p. 29.) 
 
 Chlorine, in presence of alkalis, converts acetone into chloroform : 
 C 3 H 6 + 12 Cl + H 2 = 2CHC1 3 + CO 2 + 6 HC1. 
 
 Bromine, in presence of alkalis, acts in a similar manner, producing bromoform : but 
 iodine forms only a dark pitchy mass. 
 
 4. Hydrochloric acid gas is absorbed in large quantity by acetone, and according to 
 Kane, yields chloride of mesityl (or chloropropylene) C 3 H 5 C1. Hydriodic acid gas 
 passed into acetone forms, according to Kane, iodide of mesityl, C 3 IPI, which distils 
 over with the hydriodic acid ; iodide of pteleyl C 3 H 3 I (or rather tri-iodomesitylene, 
 C 9 H 9 I 3 ), which remains suspended in the residual liquid, in the form of yellow scales ; 
 and mesityl-hypophosphorous acid, C 3 H G O.PHO, which separates in silky needles as 
 the liquid cools. Friedel (Compt. rend. xlv. 1013) stated that a solution of hydro- 
 chloric acid gas in acetone yielded, when heated to 100, acetic acid and chloride of 
 methyl (2C 3 H G + 4HC1 = C 2 H'0 2 + 4CH 3 C1), and similarly with hydriodic acid ; 
 but he has since admitted that these results were obtained with impure acetone con- 
 taining wood-spirit. 
 
 5. With pcntachloride of phosphorus, acetone yields chloropropylene, C 3 H 5 C1, boiling 
 at about 30 and methylchloracetol, a compound isomeric with chloride of propylene, 
 C 3 IPC1 2 . This body treated with silver-salts, ammonia, ethylate of sodium, or alco- 
 holic potash, is resolved into hydrochloric acid and chloropropylene, identical with the 
 body obtained by the action of alcoholic potash on C 3 H 6 C1 2 . Hence it appears that 
 acetone is related to the propylene series. (Friedel, Ann. Ch. Pharm. cxii. 236.) 
 
 6. Strong nitric acid acts violently on acetone, giving off copious red fumes, and 
 forming mesitic aldehyde, C 3 H 4 0, and nitrite of pteleyl, C 3 H 3 N0 2 . [or rather trinitro- 
 mesitylene, C 9 H 9 (N0 2 ) 3 ], together with oxalic and cyanuric acid (Kane). By 
 dropping acetone into fuming nitric acid contained in a flask externally cooled, and 
 adding water as soon as the action ceases, a heavy oil is obtained, which explodes with 
 violence when heated, giving off red fumes. (Fittig, Ann. Ch. Pharm. ex. 45.) 
 
 7. Acetone mixed with strong sulphuric acid becomes heated, and, according to the 
 quantity of acid present. and the rise of temperature which takes place, forms either 
 
28 ACETONE. 
 
 oxide of mesity], C S H 10 0, or mcsitylene, C 9 H 12 , together with mesitylsulphuric acid, 
 S0 4 .C 8 H 5 .H, and sulphurous acid. (According to Kane, the composition of mesitylsul- 
 phuric acid is C 6 H a O.H O.SO 3 , and there is formed at the same time another acid 
 called pcrmcsitylsulphuric acid, C 6 H 6 0' Z . 2 S0 4 H). 
 
 8. Glacial phosphoric acid forms with acetone a dark brown mass, partly consisting 
 of mesity Iphosphoric acid. (Kane.) 
 
 9. A solution of phos2)horus in acetone turns acid when kept for some weeks, and 
 more quickly when heated, even in perfectly air-tight vessels. According to Zeise, the 
 change consists in the formation of three peculiar acids, to which he gives the names, 
 phosphacctic, acephosgenic and acephoric acids ; but their nature and composition have 
 not been clearly made out. Products of like nature are obtained witli sulphur. Sulphide 
 of phosphorus forms with acetone a peculiar acid, and an oil which has a powerful 
 odour but no acid reaction. (Zeise.) 
 
 10. A solution of ammonia in acetone yields, by spontaneous evaporation, a colour- 
 less syrupy residue, which gradually changes into an alkaline liquid, consisting of 
 acetonine, C B H 18 N 2 , an organic base, which bears to acetone the same relation that 
 amarine bears to bitter-almond oil : 
 
 3C 3 H 6 + 2 NIP = C 9 H 18 N 2 + 3H 2 0. 
 
 The non-basic compound first formed is perhaps isomeric with acetonine. (Stadeler, 
 Chem. Gaz. 1853, 241.) 
 
 11. By the action of ammonia and sulphur on acetone, Zeise obtained a number of 
 products, which however do not present any definite characters. (Gm. ix. 11.) 
 
 12. By the simultaneous action of ammonia and hydrosulphuric acid, acetone is 
 converted into thiacetonine, a sulphuretted base consisting probably of C 9 H 9 NS 2 . 
 It crystallises in shining yellowish rhombohedrons, having an alkaline reaction, 
 sparingly soluble in water, but dissolving with facility in alcohol, ether, acetone, and 
 dilute acids. (Stadeler.) 
 
 13. When 1 volume of acetone is mixed with 1 vol. disulphide of carbon and 2 vols. 
 aqueous ammonia, laminated crystals, resembling ice, form in the liquid after a- few 
 days ; but these gradually disappear, and are succeeded by large yellow crystals, which 
 are insoluble in water, sparingly soluble in ether, but dissolve, with decomposition, in 
 warm alcohol and in boiling hydrochloric acid (Hlasiwetz, J. pr. Chem. li. 355). 
 Hlasiwetz assigns to these crystals the improbable formula C 30 H 52 N K S 9 . Stadeler, on 
 the other hand, regards them as the hydrosulphate of an organic base, carbothiacetonine, 
 C 10 H 18 N-S 2 , and represents their formation by the equation, 
 
 3C 3 H 6 + 2NH 3 + CS 2 = C 10 H 18 N 2 S 2 4- 3H 2 0. 
 
 The formula C 10 H 18 N 2 S 2 . H 2 S agrees pretty nearly with the analytical numbers ob- 
 tained by Hlasiwetz. A ' 
 platinum a brownish yelk 
 
 tained by Hlasiwetz. A cold alcoholic solution of the crystals forms with dichloride of 
 dish yellow, amorphous precipitate consisting of C 10 H 18 N 2 S 2 .PtCl 2 .PtS, 
 and with mercuric chloride a white precipitate, which, according to Stadeler, is merely 
 
 Hg 2 Cl 2 S mixed with a small quantity of hydrochlorate of carbothiacetonine. 
 
 14. Acetone heated with a mixture of hydrocyanic and hydrochloric acid, is con- 
 verted into acctonic acid, C 4 H 8 3 (Stadeler): 
 
 C 3 H 6 + CNH + 2 IPO = C 4 H 8 3 + NH 3 . 
 
 15. Acetone distilled with dichromate of potassium and sulphuric acid, gives off 
 acetic and carbonic acids, but no formic acid : 
 
 C 3 H 6 + 40 = C 2 H 4 2 + CO 2 + H 2 0. 
 
 16. Caustic alkalis, such as hydrate of potassium and quick lime, exert a dehydra- 
 ting action on acetone, several products being formed, according to the proportion of 
 water abstracted. Lowig and Weidmann, by subjecting acetone to the action of 
 hydrate of potassium, obtained a dark brown mass, consisting chiefly of xylite-oil, 
 C 12 II IS O, which boiled at 200 P , together with a resin which they call xylite-resin. 
 Volckel, by leaving acetone for some time in contact with quick lime, also obtained an 
 oil boiling above 200, which he regarded as xylite-oil. But, according to Fit tig 
 (Ann. Ch. Pharm. ex. 32), the products obtained by the action of quick lime in closed 
 vessels, are oxide of mesityl, C 6 H 10 2 , boiling at 131, and a liquid isomeric or iden- 
 tical with phorone, C 9 H 14 0. It must also be noticed that Schweizer and Weidmann 
 (J. pr. Chem. xxiii. 14) obtained xylite-oil, and likewise xylite-naphtlia, C 12 H 22 3 , by 
 the action of potash and of strong sulphuric acid on a compound produced from crude 
 wood-spirit) which those chemists called xylite, assigning to it the improbable formula 
 C 6 H 6 2 \, but which was probably nothing but somewhat impure acetone. On the 
 w r hole it appears that the action of alkalis on acetone is similar to that of sulphuric 
 acid (p. 52), consisting in an abstraction of the elements of water. The products 
 
ACETONE. 29 
 
 obtained by the action of these dehydrating agents on acetone may be arranged as fol- 
 lows, according to their boiling-points : 
 
 Boiling-point. 
 
 Xylite-naphtha . C^H^O 8 = 4 C 3 JFO - H 2 0. .110 to 320 
 
 Oxide of Mesityl C 6 H lfl O = 2 C 3 H 6 - IPO . . 131 
 
 Mesitylene . C 9 H 12 = 3 C 3 H 6 - 3H-0 . . 155 160 
 
 Phorone ? . C 9 H H = 3 C 3 H fi O - 2H 2 . . 210 220 
 
 Xylite-oil . C 12 H I8 = 4C 3 H ti O - 3H 2 . . above 200 
 
 Vapour of acetone passed over heated hydrate of potassium or potash-lime is resolved 
 into marsh-gas and carbonic anhydride : 
 
 C 3 H 6 + 2 KHO = C0 3 K 2 + 2 CH 4 ; 
 
 or if the heat is not very strong, the chief products are acetic acid, formic acid and 
 hydrogen : 
 
 C 3 H 6 + 2 KHO + H 2 = C 2 H 3 K0 2 + CHKO 2 + 6 H. 
 
 17. Sodium is violently attacked by anhydrous acetone, but without evolution of 
 hydrogen, and hydrate of sodium is separated in white flakes. The liquid gradually 
 assumes a pasty consistence, and the sodium becomes coated with oxide, so that it no 
 longer acts perceptibly on the acetone. On distilling the mass, undecomposed acetone 
 passes over first, and afterwards a watery liquid collects in the receiver, covered with 
 a yellowish oil. On pouring the distillate into a basin, so that the undecomposed 
 acetone may evaporate, the watery layer solidifies in a white crystalline mass, from 
 which the oil may be separated by pressure between paper. The crystals consist of 
 hydrate of pinacone, C 6 H 12 + 7 H 2 0, and the oily liquid is phorone, C 9 H H 0. The 
 pinacone is produced by the abstraction of 1 at. oxygen from a double molecule of 
 acetone : 
 
 2 C 3 H 6 + 2Na = Na 2 + C 6 H 12 ; 
 
 and the anhydrous pinacone thus formed appears to take water from another portion of 
 the acetone, converting it into phorone : 
 
 3 C 3 H 6 - 2 H 2 = C 9 H 14 0. 
 
 By heating the crystals of hydrated pinacone in a narrow glass tube, a viscid liquid 
 is obtained, which absorbs water rapidly from the air, and is reconverted into the 
 crystalline hydrate. This liquid appears to be anhydrous pinacone ; but it is difficvilt 
 to expel all the water (Stadeler, Ann. Ch. Pharm. cxi. 277). Fittig (ibid. ex. 23) 
 assigns to the hydrated crystals, the formula C 3 H 6 + 3H 2 0, regarding them as the 
 hydrate of paracetone, a compound isomeric with acetone, which he also states is ob- 
 tained in anhydrous crystals, by the action of ammonia on acetone. Fittig's formulae 
 do not, however, agree with the results of analysis so well as Stadeler' s (see PINACONE); 
 moreover it is very unlikely that sodium should act with violence on acetone, without 
 abstracting a portion of its oxygen. The action of ammonia on acetone, produces, ac- 
 cording to Stadeler, not a crystalline compound, but a liquid organic base, acetonine 
 (p. 32). 
 
 18. Dry dichloride of platinum dissolves in acetone with evolution of heat, and 
 forms a brown solution, which, when evaporated, gives off hydrochloric acid, and leaves 
 a resinous mass, containing among other products, a yellow crystalline substance 
 called acechloride of platinum or cMoroplatinite of mesityl, C 6 H 10 O.Pt 2 Cl 2 . (?) This 
 compound may be obtained in larger quantity, by triturating dichloride of platinum 
 with acetone to the consistence of a thick paste, leaving the mass in a close vessel till 
 it liquefies and ultimately forms crystals, washing these crystals with acetone, and 
 purifying them by crystallisation from boiling acetone. Acechloride of platinum thus 
 obtained, is yellow, inodorous, sparingly soluble in water, alcohol and ether, more 
 readily in aqueous chloride of potassium or sodium. Cold acetone dissolves ^ of it ; 
 boiling acetone a little more. The aqueous solution reddens litmus. The compound is 
 decomposed and dissolved by potash, forming a brown solution. When boiled with 
 water, it deposits a black substance called aceplatinous oxide, probably C 2 Pt 2 0. The 
 same substance is deposited on boiling the mother-liquor of acichloride of platinum. 
 The acichloride yields by distillation a residue of carbide of platinum, PtC. (Zeise, 
 Ann. Ch. Pharm. xxxiii. 29 ; Grm. ix. 31.) 
 
 SUBSTITUTION-PRODUCTS OF ACETONE. Chloracetones. Each of theatoms of hydro- 
 gen in acetone may be replaced by chlorine, giving rise to six chlorinated acetones. The 
 first of these compounds is obtained by the action of nascent chlorine on acetone ; 
 the second by that of chlorine or the oxides of chlorine on acetone ; the third and 
 fourth by the action of chlorine on crude wood-spirit, probably containing acetone ; 
 the fifth and sixth can only be obtained by the action of chlorine or the oxides of 
 chlorine on other organic compounds. 
 
30 ACETONE. 
 
 Monochloracctonc, C 3 IPC10, is obtained by the action of a feeble electric current 
 (from three Bunsen's cells) on a mixture of acetone and hydrochloric acid, the 
 chlorine set free at the positive pole from the hydrochloric acid, acting on the acetone 
 and taking the place of 1 at. hydrogen. It is an oily, colourless liquid, which, when 
 separated from the watery solution and rectified, boils at 117, has a sp. gr. of 1*14 at 
 14, and vapour-density = 3 '40. Its vapour acts strongly on the nose and eyes, pro- 
 ducing a copious flow of tears. (Eiche, Compt. rend. xlix. 176.) 
 
 Dichlor acetone, C 3 H 4 C1 2 (Kane's mesitic chloral}, is produced by passing dry chlorine 
 into anhydrous acetone, or better, according to Stadeler, by mixing acetone in a capa- 
 cious flask with twice its volume of strong hydrochloric acid diluted with an equal 
 bulk of water, and adding pulverized chlorate of potassium by small portions. It is 
 an oily liquid of sp. gr. 1-331 (Kane); 1*236 at 90 (Fittig). Boils at 116'5 (Sta- 
 deler); at 121 0- 5 (Fittig). Vapour-density 3 -2. Its vapour smells like chloro- 
 form at first, but, after a few seconds, attacks the nose and eyes with violence. The 
 liquid blisters the skin like cantharides, producing wounds which are difficult to heal 
 (Liebig, Kane, Fittig.) It is insoluble in water, but mixes in all proportions with 
 alcohol and ether. 
 
 Trichloracetonc, C 3 H 3 CPO, is obtained by the action of chlorine on wood-spirit. 
 "When chlorine gas is passed into ordinary (unpurified) wood-spirit, crystals are formed 
 consisting of C S H 10 C1 2 2 (chloromcsitate of methi/lene), biit if the action of the chlorine 
 be further continued, the crystals disappear, and an oily liquid is formed, which is 
 terchlorinated acetone. It is heavier than water, has an extremely pungent odour, 
 and cannot be distilled without decomposition. ( B o u i s . ) 
 
 Tctrachloracetone, C 3 H 2 C1 4 0, is obtained by dissolving the crystals just mentioned 
 in wood-spirit and passing chlorine through the solution. It is an oily very volatile 
 and pungent liquid, which blisters the skin. When exposed to moist air, it forms 
 crystals containing C 3 H 2 C1 4 + 4 H 2 0, which melt at 35, and dissolve in water, alcohol 
 and ether, forming solutions which are not precipitated by nitrate of silver. The crystals 
 distilled with phosphoric anhydride yield the original anhydrous compound. This 
 and the preceding compound are doubtless formed from acetone contained in the wood- 
 spirit. (Bouis, Ann. Ch. Phys. [3] xxi. 111.) 
 
 Pentachloracetone, C 3 HC1 5 0, is obtained by the action of a mixture of chlorate of 
 potassium and hydrochloric acid on seveial organic compounds, viz. kinic, citric, 
 gallic, pyrogallic, catechucic and salicylic acids, also kinone, muscular flesh, albumin, 
 indigo and tyrosin. The best mode of preparing it is to add a considerable quantity 
 of chlorate of potassium to a boiling solution of kinic acid, and then add strong hydro- 
 chloric acid in such portions that chlorine and chlorous acid may be continually 
 evolved. The distillate is concentrated by rectification over chloride of calcium. It 
 then, if tolerably pure, solidifies into a crystalline hydrate when covered with water 
 at 4 or 5. If no solidification takes place, the product is contaminated with other 
 oils, and must be purified by agitating it with ice-cold water, and heating the de- 
 canted and clarified liquid to 60 ; the greater part of the oily impurities then separate 
 out. To purify it completely, it is converted into the crystalline hydrate as above men- 
 tioned, and the crystals are pressed between paper. The pure anhydrous compound 
 may be obtained by melting the crystals in a glass tube, whereupon they separate 
 into a watery and an oily liquid, the latter, which is undermost, being pure anhydrous 
 pentachloracetone. It is a colourless rather mobile oil, having a burning aromatic 
 taste, and an odour like that of chloral. Sp. gr. between 1-6 and 1*7. It remains 
 liquid at 20 and boils at 190. The hydrate, which crystallises in rhombic tables, 
 contains 4 atoms of water. Water dissolves ^ of its volume of anhydrous penta- 
 chloracetone, and on the other hand, this compound takes up a certain quantity of 
 water without change of appearance ; but it then becomes turbid at the heat of the 
 hand, like hydrated conine. Pentachloracetone dissolves readily in alcohol and ether. 
 The alcoholic solution mixed with alcoholic potash deposits chloride of potassium 
 together with scaly crystals, probably consisting of dichlor acetate of potassium, and 
 the solution is found to contain formic acid : 
 
 C 3 HCPO + H 2 = CHOI 3 + C 2 H 2 C1 2 2 
 
 Chloroform. Dichlnracetic 
 acid. 
 
 and: CHOP + 2 H 2 = 3 HC1 + CH 2 2 . 
 
 (Stadeler, Ann. Ch. Pharm. cxi. 277.) 
 
 Hexachloracctone, C 3 C1 6 (discovered by Plantamour, who assigned to it the formula 
 (C 8 C1 16 3 ), is obtained by the action of chlorine in sunshine on an aqueous solution of 
 citric acid. It is an oily liquid of peculiar pungent odour, sp. gr. 1*75 at 10, and 
 boiling between 200 and 201. It makes transient grease spots upon paper, gra- 
 dually reddens litmus paper, and forms with water, at temperatures not above 6, a 
 
ACETONES. 31 
 
 crystalline hydrate, C 3 C1 6 O 4- H 2 0, which melts at a temperature above 15, with 
 separation of an oil. 
 
 Bromacetone, C 3 H 5 BrO, is produced similarly to monochloracetone, viz. by the 
 action of a feeble electric current on a mixture of acetone and hydrobromic acid. It is 
 colourless when first prepared, but turns brown in a few minutes, and is decomposed by 
 distillation, the greater portion however passing over between 140 and 145. Its va- 
 pour irritates the eyes so strongly that the spilling of a few drops renders the air of 
 a room unendurable. (E i c h e. ) 
 
 lodacetone appears also to be formed in small quantity by the electrolysis of a mix- 
 ture of acetone and hydriodic acid. (Kiche.) 
 
 Methylacetone, C 4 H 8 = C 3 H 5 (CH 3 )0. When crude commercial acetone, 
 or, better, the brown liquid which floats on the top of it, is dehydrated with chloride 
 of calcium and then subjected to fractional distillation, pure acetone passes over below 
 60 and the distillate which is obtained between 60 and 130, yields, after about 
 thirty fractionations, three distinct compounds, viz. methylacetone, boiling between 75 
 and 77, ethylacetone, C 5 H 10 0, between 90, and 95 and dumasin, C 6 H 10 0, between 
 120 and 125. (Fittig, Ann. Ch. Pharm. ex. 18.) 
 
 Methylacetone is a colourless liquid of sp. gr. 0*838 at 19 C. having the odour of 
 acetone, miscible in all proportions with water and alcohol. It combines with acid sul- 
 phite of sodium, forming a crystalline compound, 2C 4 H 7 NaS0 3 + 3 H-0, which is very 
 soluble in water. 
 
 Ethylacetone, C 5 H 10 = C 3 H 5 (C 2 H 5 )0. Transparent, colourless liquid, smelling 
 faintly like acetone, sparingly soluble in water, but miscible in all proportions with 
 alcohol, sp. gr. 0*842 at 19. Boils between 90 and 95. With acid sulphite of sodium 
 it forms the compound 2C 5 H 9 NaS0 3 + 3 H 2 0, which crystallises in colourless nacreous 
 laminae very soluble in water. (Fittig.) 
 
 ACETONES or ELETOCTES. This term is applied to a class of compounds 
 which, like that just described, are composed of an acid-radicle united with an 
 alcohol-radicle. Nearly all the acetones at present known consist of the radicle of 
 a fatty acid combined with one of the corresponding alcohol-radicles ; their general 
 formula being C m H 2m + 1 . C 11 !! 211 " 1 0. where m may be either greater or less than n. 
 When m = 0, the acetone becomes an aldehyde, H.C n H 2n - = C n H 2n O ; the 
 acetones may therefore be regarded as aldehydes in which 1 at. hydrogen is re- 
 placed by an alcohol-radicle. 
 
 Acetones are either simple or compound. In the simple acetones, m = n 1, so that 
 their general formula is C n ~ 1 H 2n - 1 .C B H 2n ~ 1 0. = C 2n ~ 1 H 4u - 2 ; thus, acetic acetone, 
 for which n =_ 2, is CH 3 .C 2 H 3 0. The simple acetones are produced by heating the 
 barium or calcium salts of the fatty acids, 2 atoms of the salt being decomposed in 
 such a manner that the acid radicle of one of them is resolved into the next lowest 
 alcohol-radicle and carbonyl (CO), so that a carbonate of calcium or barium is formed 
 at the same time : 
 
 CH 2n - 1 0) n CO.C n --H 2n - J ) n C B H 2 - 1 0) C0) n , 
 Ca J u Ca i u = C n - 1 H>- 1 j + Ca 2 j U> 
 
 The formation of acetic acetone or methyl-acetyl (p. 26) by the decomposition of 
 acetate of barium, is a particular example of this process. In like manner, propione 
 or ethyl-propionyl, C 2 H 5 .C 3 H 5 0, butyrone or trityl-butyryl, C 3 H 7 .C 4 H 7 0, valerone or 
 tetryl-valyl, C 4 H 9 .C 5 H 9 0, are produced by the decomposition of the propionates, butyrates 
 valerates, &c. 
 
 These simple acetones were the only ones known, till Williamson in 1851 (Chem. 
 Soc. Qu. J. iv. 238) showed that, by distilling a mixture of the barium or calcium salts 
 of two different fatty acids, acetones may be obtained in which an acid radicle is as- 
 sociated with an alcohol-radicle which is not the next below it in the series [m greater or 
 less than n 1] : these are the so-called compound or intermediate acetones. If the 
 acids whose salts are distilled together contain p and atoms of carbon, the decom- 
 position may be represented by the equation : 
 
 Ca | + Ca [ = Ci- 1 H 2 i- 1 [ + C 
 
 or, since it is indifferent which of the acid radicles we suppose to be decomposed, the 
 formula of the acetone thus produced may also be ^5^ [ Thus a mixture of 
 
 acetate and valerate of calcium yields by distillation either methyl-valyl, CH 3 .C 5 H 9 0, or 
 tetryl-acttyl, C 4 H 9 .C 2 H 3 0, either of these formulas being equal to C 6 H 12 0. Possibly 
 two isomeric compounds having these formulae, may be produced together. If one of 
 
 the mixed salts is a formate, ^ J 0, the alcohol-radicle separated from it is reduced 
 to an atom of hydrogen, and the acetone becomes an aldehyde. (See AI/DEHYDES.) 
 
C 5 H 10 = CIP . C 4 H 7 
 C 5 H 10 = C-IP.C 3 H 5 
 C K H 12 = C* H 5 . C 4 H' O 
 C fi H 12 = C H 3 . C 5 H 9 
 C 7 H 14 = C 3 H 7 . C 4 H 7 
 C 8 H 16 = C H 3 . C 7 1I 13 
 C 9 H 18 = C 4 H 9 . C 5 H 9 
 C n H 22 = C 5 H".C 6 H n O 
 C is H 3o = C'H 15 . C 8 H 15 
 C 17 II 31 = C 8 H 17 . C 9 H 17 
 C"H 23 . C 12 IP 3 
 
 C 31 IP 2 = C 15 H 31 . C 16 H 31 
 
 32 ACETONES. 
 
 The compound acetones are also produced, together with the simple acetones and 
 other products, when a calcium or barium salt of a fatty acid is distilled alone. Thus 
 the distillation of butyrate of calcium yields, besides butyrone and a small quantity of 
 butyral, a considerable number of hydrocarbons (Berthelot, Compt. rend, xliii. 236); 
 and among these, methyl and ethyl appear to occur, and give rise to the formation oiethyl- 
 butyryl, C 2 H 5 .C 4 H 7 0, and mcthyl-butyryl, CH 3 .C 4 H 7 0. (Friedel, Compt. rend, 
 xlvii. 553.) 
 
 The following is a list of the acetones, or ketones, at present known, which are de- 
 rived from the fatty acids : 
 
 Methyl-acetyl (Acetone) . . . C 3 H 6 = CH 3 . C 2 H 3 
 
 Methyl-butyryl 
 
 Ethyl-propionyl (Propione) 
 
 Ethyl-butyryl .... 
 
 Methyl-valyl . . 
 
 Trityl-butyryl (Butyrone) . 
 
 Methyl-oananthyl 
 
 Tetryl-valyl (Valerone) 
 
 Amyl-capronyl (Capronone) 
 
 Heptyl-capryl (Caprylone) 
 
 Octyl-pelargonyl (Pelargonone) 
 
 Laurone 
 
 Myristone .... 
 Palmitone or Margarone . 
 Stearone 
 
 Some of the compounds in this table are isomeric, e. g. propione and butyracetone. 
 Among the higher terms of the series, the number of such isomeric compounds is doubt- 
 less very great, though but few of them have yet been obtained. 
 
 These bodies, with the exception of acetic acetone, have not been much studied. 
 Their reactions, so far as they are known, resemble those of common acetone already 
 described. The lower terms of the series unite with the acid sulphites of the alkali- 
 metals, generally forming c^stalline compounds. The best mode of purifying the 
 acetones is to shake them up with a strong aqueous solution of acid sulphite of potassium 
 or sodium, and distil the resulting solid compound with potash. The acetone then 
 passes over pure. 
 
 But little is known respecting acetones belonging to other series of acids. Two 
 have been formed containing the radicle benzoyl, viz. benzophcnone, or phenyl-benzoyl, 
 C 13 H 10 = C 6 H 5 .C 7 H 5 0, the acetone of benzoic acid, obtained by heating benzoate of 
 potassium ; and methyl-benzoyl, C 8 H 8 = CH 3 .C 7 H 5 0, obtained by distilling together 
 equivalent quantities of acetate and benzoate of calcium (Friedel). Benzophenone 
 treated with nitric acid yields nitrobenzophenone, C 13 H 8 (N0 2 ) 2 0. 
 
 The calcium-salt of camphoric acid, which is dibasic, yields by dry distillation an oily 
 liquid called phorone, which has the constitution of an acetone : 
 
 C 9 H"0 + C J 
 
 Phorone. 
 
 and suberate of calcium, C 8 H I2 4 Ca 2 , yields in like manner suberone, C 7 H 14 0, mixed 
 with other products. These are the only two acetones of dibasic acids yet discovered. 
 (Gerhardt, Traite, iv. 640.) 
 
 A-CETONIIffB. C 9 H 18 N 2 . Produced by the action of ammonia on acetone (p. 28), 
 either when a solution of ammonia in acetone is left to evaporate spontaneously to a 
 syrup, or when acetone saturated with ammonia is heated to 100 in a sealed tube. 
 It is a colourless liquid, having a peculiar urinous odour, a burning taste and alkaline 
 reaction, easily soluble in water, alcohol, and ether. It unites with acids, forming salts. 
 The oxalate C 9 H 18 N 2 .C-H 2 4 + H 2 crystallises from a hot saturated alcoholic solution 
 in delicate colourless prisms, which are soluble in water, insoluble in ether, give off half 
 their water at 100, the rest between 115 and 120, and decompose at a higher tem- 
 perature. The ckloroplatinatc, C 9 H 18 N 2 .HGl.PtCl 2 , forms lustrous, orange-coloured, four- 
 sided prisms with oblique terminal faces. It is soluble in water, also in boiling alcohol 
 containing hydrochloric acid; insoluble in ether. (Stadeler, Ann. Ch. Pharm. cxi. 30? .^ 
 
 ACETONTTRIIiE. C 2 H 3 K A compound obtained by ti eating acetate of am- 
 monium or acetamide with phosphoric anhydride : 
 
 C 2 H 3 2 .NH 4 - 2H 2 = C 2 H 3 tf ; and C 2 H 5 NO - IPO = C 2 IPN. 
 
 Acetate of ammonium. Acetamide. 
 
ACETONYL ACETYL. 33 
 
 It is identical with cyanide of methyl, obtained by distilling cyanide of potassium with 
 niethylsulphate of potassium. (See CYANIDE OF METHYL.) 
 
 Chloracetonitrile, C'-'C1 3 N, or cyanide of trichloromethyl, CCP.CN, is obtained by dis- 
 tilling trichloracetate of ammonium or trichloracetamide with phosphoric anhydride. 
 It is a liquid boiling at 81; of sp. gr. 1-4441. With boiling potash, it yields ammonia 
 and trichloracetate of potassium. It is violently attacked by potassium. 
 
 ACETOWYI*. C 6 H 12 . A hypothetical radicle supposed by Hlasiwetz to exist in the 
 yellow crystals formed by the action of ammonia and bisulphide of carbon on acetone. 
 Hlasiwetz assigns to these crystals the formula C 30 H 5 -N 6 S 9 , and regards them as sul- 
 pkocyanate of acetom/l with sulphocarbonate of sulphacctonyl = 2(C 6 H 12 .2CNS) 4- 
 2 C 6 H 12 S.C 2 H 4 N 2 S 3 . Stadeler's view of the constitution of this compound (p. 52), is 
 much more probable. 
 
 ACETOSYIi. The name given by G-erhardt to the hypothetical radicle C 2 H 3 or 
 C 1 H 3 , originally called acetyl, and supposed by some chemists to exist in acetic acid and 
 its derivatives. (See ACETYL and VINYL.) 
 
 ACETOXYL. Kolbe's name for the radicle C 2 H 3 or C*H 3 2 , usually called 
 acetyl, which see. 
 
 ACETUREID. Syn. of Acetyl-urea. 
 
 ACETYX,. C 2 H 3 or C*H 3 2 . Acctoxyl, Othyl A. radicle not yet isolated, 
 but supposed to exist in acetic acid and its derivatives, the rational formula of acetic 
 
 /^2TT3(^) ) f^*TT3O ) 
 
 acid being, on this hypothesis, > 0, and that of acetic anhydride, p 2 TT 3 / > [ 0. 
 
 The reason for assuming the existence of this radicle in the acetic compounds is, 
 that the formula to which it leads, affords the simplest representation of the most im- 
 portant reactions of acetic acid and the other bodies of the series. Thus, when acetic 
 
 acid -rr f is treated with a metallic oxide or hydrate, the basic atom of hydro- 
 ^ C 2 H 3 
 
 gen is replaced by a metal, and an acetate of that metal , .- is produced. On 
 treating the same compound with pentasulphide of phosphorus, P 2 S 5 , the external atom 
 
 O2TT3/") ) 
 
 of oxygen is replaced by sulphur, and thiacetic acid, S is formed ; and by the 
 
 action of pentachloride of phosphorus, the group HO is replaced by Cl, and chloride 
 of acetyl C 2 H 3 O.C1 is produced. (See ACETIC ACID, and ACIDS, p. 44.) 
 
 Formerly, however, acetic acid, and the other members of the same group, were sup- 
 posed to be derived from the radicle C 2 H 3 or C 4 H 3 ; and to this the name acetyl was 
 originally applied. Thus, anhydrous acetic acid was regarded as a trioxide of this 
 radicle, viz. C*H 3 .0*, and the hydrated acid as a compound of this oxide with water, 
 viz. C*H 3 3 .HO. &c. To apply the same name to two different radicles would of 
 course create confusion ; hence the terms acetoxyl proposed by Kolbe, and othyl (ab- 
 breviation of oxygen-ethyl) by Williamson, for the radicle C 2 H 3 0. Most chemists, 
 however, are of opinion, that the radicle supposed to exist in acetic acid and its deri- 
 vatives, is most appropriately designated by the term acetyl; and accordingly, this term is 
 now generally applied to the group C 2 H 3 0, while C 2 H 3 , which more properly belongs 
 to another series of compounds derived from alcohol, ether and ethylene, and having 
 a less intimate distant relation to acetic acid, is called by a different name. (See 
 ACETOSYL and VINYL.) 
 
 Acetyl, C 2 H 3 is regarded by Kolbe as a compound or conjugate radicle, 
 containing methyl and carbonyl, viz. CH 3 ,CO ; and in like manner, propionyl, C 3 H 5 O, 
 is regarded as a compound of ethyl: C 2 H 5 .CO ; butyryl, C 4 H 7 O, as a compound 
 of trityl : C 3 H 7 .CO, &c. each radicle of a fatty acid being supposed to contain the 
 next lowest alcohol-radicle associated with carbonyl. This view, which has been 
 adopted by Gerhard t, in his " Traite de Chimie Organique" is based upon the fact 
 that certain methyl-compounds may be obtained from acetic acid and its derivatives, 
 and the contrary ; similar transformations likewise taking place in the other terms 
 of the series. Thus, a solution of acetate of potassium subjected to electrolysis, yields 
 methyl and carbonic anhydride : 
 
 CH 3 .CO = CH 3 + CO 2 + H 
 
 "7 - ' 7? Methyl. 
 
 Acetic acid. 
 
 Cyanide of methyl boiled with aqueous potash gives off ammonia and forms acetate 
 of potassium: 
 
 CH'.CN + KHO + H 2 = CHS - C JO + NH 3 ; 
 
 Cyanide of * - , ' 
 
 methyl Acetate of 
 
 potassium. 
 
 VOL. I. D 
 
34 
 
 ACETYL. 
 
 and acetate of ammonium (CH 3 .CO).NH 4 .0, treated with.phosphoric anhydride, gives off 
 2H-0, and is reduced to cyanide of methyl, CH 3 .CN. Marsh-gas, or hydride of methyl, 
 CH 3 .H, is produced by the decomposition of acetates (p. 12) ; and cacodyl As(CH 3 ) 2 , 
 by the decomposition of acetic acid. The formation of acetone or methyl-acetyl, 
 CH 3 .C 2 H 3 O, from acetates, and the corresponding transformations of propionates, 
 valerates, &c. (p. 26), is another example of the same kind of decomposition. Again 
 it has been shown by "Wanklyn (Chem. Soc. Q. J. xi. 103), that sodium-ethyl 
 subjected to the action of carbonic anhydride is converted into propionate of sodium : 
 C 2 H 5 .Na + CO 2 = (C 2 H 5 .CO).Na.O ; 
 
 Sodium- Vropionate of sodium, 
 
 ethyl. 
 
 and in like manner, acetate of sodium may be prepared from sodium-methyl. 
 Lastly, many organic compounds, such as sugar, starch, alcohol, and acetone, which 
 are convertible into acetic acid by oxidation, may also, under the influence of chlorine, 
 or bromine, be converted into bodies belonging to the methyl-series, viz. chloroform, 
 C(HC1 2 ).C1, and bromoform, C(HBr 2 ).Br. It must be observed, however, that the 
 representation of acetic acid as a methyl-compound applies chiefly to a state of transi- 
 tion, just as the acid is being produced from or converted into a body belonging to a 
 different series, and exhibiting different chemical relations ; so long as we are concerned 
 with the transformation of one acetyl-compound into another, such as that of acetic 
 acid into chloride or bromide of acetyl, or of the chloride into acetic anhydride, the 
 
 C 2 H 3 ) 
 formula TJ > is sufficient for the representation of all the changes which take 
 
 place. 
 
 The hydrogen in acetyl may be partly or wholly replaced by other elements, viz. 
 chlorine, bromine, &c. ; and hence arise the conjugate or derivative radicles, bromacetyl, 
 chloracetyl, &c., which, like acetyl itself, are hypothetical, not having yet been isolated. 
 The following table exhibits a general view of the compounds of acetyl and of the 
 radicles derived from it by substitution. 
 
 Bromide of Acetyl 
 
 Chloride 
 
 Iodide 
 
 Hydride 
 
 Hydrate 
 
 Oxide 
 
 Peroxide 
 
 Sulphydrate 
 
 Sulphide 
 
 Nitrides 
 
 Hydrate of Bromacetyl . 
 
 Nitride 
 
 Hydrate of Dibromacetyl 
 
 Nitride . 
 
 Hydride of Tribromacetyl 
 
 Hydrate of Chloracetyl . 
 
 Nitride . 
 
 Chloride of Trichloracetyl 
 
 Hydride 
 
 C 2 H 3 O.Br 
 
 C 2 H 3 O.C1 
 
 C 2 H 3 O.I 
 
 C 2 H 3 O.H 
 
 C 2 H 3 O.H.O 
 
 (C 2 H 3 0) 2 .0 
 
 C 2 H 3 0.0 
 
 C 3 H 3 O.H.S 
 
 (C 2 H 3 0) 2 .S 
 (C 2 H 3 O.H 2 .N 
 \ (C 2 H 3 0) 2 .H.N 
 (C 2 H 3 O.C 2 H 5 .H.N 
 &c. &c. 
 
 C 2 H 2 BrO.H.O 
 
 C 2 H 2 BrO.H 2 .N 
 
 C 2 HBr 2 O.H.O 
 
 C 2 HBr 2 O.H 2 .N 
 
 C 2 Br 3 O.H 
 
 C 2 H 8 C10.H.O 
 
 C 2 H 2 C10.H 2 .N 
 
 C 2 C1 3 O.C1 
 
 C'CPO.H 
 
 Hydrate C 2 C1 3 O.H.O 
 
 Nitride .... 
 Phosphide 
 
 Hydrate of lodacetyl 
 Nitride . 
 
 Hydrate of Di-iodacetyl . 
 
 Nitride 
 
 Hydride of Tri-iodacetyl . 
 
 C 2 C1 3 O.H 2 .N. 
 
 C 2 C1 3 O.H 2 .P. 
 
 C 2 H 2 IO.H.O 
 
 C 2 H 2 IO.H 2 .N 
 
 C 2 HI 2 O.H.O 
 
 C 2 HI 2 O.H 2 .N. 
 
 C'FO.H. 
 
 Aldehyde 
 Acetic acid 
 Acetic anhydride 
 
 Thiacetic acid 
 Thiacetic anhydride 
 Acetamide 
 Diacetamide 
 Ethyl-acetamide 
 
 Bromacetic acid 
 
 Bromacetamide 
 
 Dibromacetic acid 
 
 Dibromacetamide 
 
 Bromal 
 
 Chloracetic acid 
 
 Chloracetamide 
 
 Chloraldehyde 
 
 Chloral 
 
 Trichloracetic acid 
 
 Trichloracetamide 
 
 Trichloracetyphide 
 
 lodacetic acid 
 
 lodacetamide 
 
 Di-iodacetic acid 
 
 Di-iodacetamide 
 
 lodal 
 
 Bromide of Acetyl. C 2 H 3 O.Br. Prepared by slowly adding glacial acetic acid to 
 pentabromide of phosphorus in a tubulated retort, distilling, and rectifying : 
 
 C 2 H 3 O.H.O + PBr'.Br 8 = C 2 H 3 O.Br + HBr + PBr 3 0. 
 
 It is a colourless liquid, boiling at 81. When exposed to the air, it fumes strongly 
 and immediately turns yellow. It colours the skin yellow, and is said to impart to it 
 the odour of phosphuretted hydrogen ; but this must arise from impurity. Water 
 
ACETYL. 35 
 
 decomposes it into acetic and hydrobromic acids. (Ritter, Ann. Ch. Pharm. xcv. 
 209.) 
 
 Chloride of Acetyl. C 2 H 3 O.C1. Produced by the action of oxychloride of phos 
 phorus on acetate of potassium : 
 
 3(C 2 H 3 O.KO) + POC1 3 = 3C 2 H 3 OC1 + P0 4 E? ; 
 
 or in the same manner as the preceding compound, by distilling glacial acetic acid with 
 pentachloride of phosphorus : 
 
 C 2 H 3 O.H.O + PCP.C1 2 . = C 2 H 3 O.C1 + HC1 + PCPO. 
 
 Gerhardt, who discovered this compound (Ann. Ch. Phys. [3] xxxvii. 294), pre- 
 pared it by adding oxychloride of phosphorus, drop by drop, to fused acetate of 
 potassium. A brisk action then takes place, and sufficient heat is produced to cause 
 the chloride of acetyl to distil over into the receiver, which must be well cooled. The 
 distillate may be freed from excess of oxychlor-ide of phosphorus by re-distillation over 
 acetate of potassium, then distilled by itself, and the liquid which passes over at 55 
 collected apart. The re-distillation over acetate of potassium is, however, attended 
 with some loss, in consequence of the formation of acetic anhydride. 
 C 2 H 3 O.C1 + C 2 H 3 O.K.O = (C 2 H 3 0) 2 + KC1. 
 
 For this reason, Ritter recommends the preparation of chloride of acetyl by the action 
 of pentachloride of phosphorus on glacial acetic acid, the product being thereby ob- 
 tained in larger quantity and more easily purified. 
 
 Chloride of acetyl is a colourless, very mobile, strongly refracting liquid, of specific 
 gravity M25 at 11, 1-1305 at 0, and 1-1072 at 16 (Kopp). Boils at 55. Vapour- 
 density, 2*87 (G-erhardt) : by calculation (2 vol.) = 2718. It fumes slightly in the air, 
 and has a pungent odour like that of acetic and hydrochloric acid. The vapour at- 
 tacks the eyes and respiratory organs very strongly. 
 
 Chloride of acetyl is decomposed with explosive violence by water, yielding acetic 
 and hydrochloric acids : 
 
 C 2 H 3 OC1 + H 2 = C 2 H 4 2 + HCL 
 Ammonia acts strongly upon it, forming acetamide : 
 
 C 2 H 3 O.C1 + H 3 N = C 2 H 3 O.H 2 .N + HC1. 
 
 Similarly with phenylamine, it forms phenylacetamide C 2 H 3 O.C 8 H 5 .H.N. Distilled 
 with acetate of potassium, it yields acetic anhydride : 
 
 C 2 H 3 O.K.O + C 2 H 3 O.C1 = (C 2 H 3 0) 2 + KC1 ; 
 and with benzoate of potassium it forms benzoate of acetyl or acetate of benzoyl : 
 
 C : H 5 O.K.O + C 2 H 3 O.C1 = C 2 H 3 O.C 7 H 3 0.0 + KC1; 
 
 and similarly with the salts of other acids. With thiacetate of lead, it forms chloride 
 of lead, and probably also thiacetic anhydride : 
 
 C 2 H 3 O.Pb.S + C 2 H 3 O.C1 = (C 2 H 3 0) 2 S + PbCl. 
 
 When it is heated with zinc in a sealed tube, the metal is strongly attacked ; and a 
 black tarry subtance is formed, from which water dissolves chloride of zinc, and sepa- 
 rates a liquid having an ethereal odour. 
 
 Hydride of Acetyl. See ALDEHYDE. 
 
 Iodide of Acetyl. C 2 H 3 O.I. Obtained by the action of iodide of phosphorus on 
 acetic anhydride (Guthrie, Phil. Mag. [4] xiv. 183), or on acetate of potassium ; 
 (Cahours, Compt. rend. xliv. 1253). After being shaken up with mercury and re- 
 distilled, it forms a transparent colourless liquid, of sp. gr. 1-98 at 17. It boils at 
 108 (G-uthrie); between 104 and 105 (Cahours). It fumes strongly in the air, 
 has a very pungent odour, and an intensely sour caustic taste. 
 
 Iodide of acetyl is partially decomposed by distillation. Water decomposes it with 
 violence, forming hydriodic and acetic acids. It acts strongly upon alcohol, forming 
 acetate of ethyl. It is decomposed by zinc and by sodium at ordinary temperatures, 
 also by mercury in direct sunshine, iodide of mercury being formed, and little or no 
 permanent gas being given off. 
 
 Peroxide of Acetyl. C 2 II 3 0.0. Discovered byBrodie in 1858 (Proceedings of 
 the Royal Society, ix. 361.) It is obtained by mixing acetic anhydride and peroxide of 
 barium, in equivalent proportions, in anhydrous ether. The mixture must be effected 
 very gradually, as it is attended with great evolution of heat. The products are 
 acetate of barium and peroxide of acetyl, the latter remaining dissolved in the ether : 
 
 (C 2 H 3 0) 2 .0 + BaO = C 2 H 3 O.Ba.O + C 2 H 3 0.0. 
 D 2 
 
36 ACETYLOUS ACID ACHMITE. 
 
 The ethereal solution, after filtration from the acetate of barium, is carefully distilled 
 at a low temperature, and the remaining liquid is washed three or four times with 
 water till the wash-water ceases to be acid. The residue is peroxide of acetyl. 
 
 It is a viscid liquid, extremely pungent to the taste, the smallest portion placed upon 
 the tongue burning like cayenne pepper. It is a powerful oxidising agent, and highly 
 explosive : a drop heated on a watch-glass explodes with a loud report, shivering the 
 glass to atoms. Baryta-water poured upon it is instantly converted into peroxide of 
 barium, with formation of acetate of barium. 
 
 Acetyl-urea. (See UREAS (Compound) and CABBAMIDE.) 
 
 ACETYXiENE. (See ADDENDA, p. 1111.) 
 
 ACETYXiOUS ACID. AXtDEHlTDXC ACID. Lampic acid, Etheric acid, 
 An acid supposed to be produced by the slow combustion of ether or of alcohol, 
 and under certain circumstances by the oxidation of aldehyde. When ether is 
 repeatedly distilled, or allowed to fall in successive drops on a solid body heated to 
 about 129, so that its vapour may come in contact with the air at a high temperature, 
 a disagreeable pungent odour is produced, supposed to be that of aldehydic acid. The 
 compound possessing this odour is formed in larger quantity, when a spiral of fine 
 platinum wire, previously heated to redness, is suspended over a basin containing 
 ether, and the whole covered with a bell-jar. The wire then continues to glow, the 
 ether undergoing a slow combustion without flame, and an acid liquid is formed, 
 which runs down the sides of the bell-jar, and may be collected in a vessel placed 
 below. This liquid is colourless, has a very sour taste, and gives off a pungent vapour 
 which excites tears, and causes great oppression when inhaled. The same compoimd 
 is obtained, according to Liebig, by heating oxide of silver with aqueous aldehyde ; 
 part of the silver is then reduced, while the other portion remains in solution in the 
 form of acetylite of silver, and by decomposing this silver-salt with sulphuretted 
 hydrogen, the acid may be obtained in the free state. It is, however, very liable to 
 decompose, as also are its salts. When the silver-salt is boiled with baryta-water, 
 silver is reduced and acetate of barium remains in solution. 
 
 2C 2 IPAgO + 2BaHO = C 2 H 3 BaO + C 2 H 3 Ba0 2 + 2Ag + H 2 
 
 Aidehydate of Hydrate of Aldehydate Acetate of 
 
 silver. barium. of barium. barium. 
 
 Gerhardt (Traite i.) is of opinion that the so-called aldehydic or acetylous acid is 
 merely a mixture of aldehyde and acetic acid, the aldehydate or acetylite of silver being 
 in fact merely aldehyde in which 1 atom hydrogen is replaced by silver. 
 
 ACHIX.X.EA TCXX.X.EFOX.ITriM[ (Millefoil.) The ash of this plant has been 
 analysed by Way and Ogston. 100 parts of the dry herb left 13*45 per cent, ashes con- 
 taining in 100 parts 30*37 parts of potash, 13*40 lime, 3*01 magnesia, 0*21 sesquioxide of 
 iron, 2*44 sulphuric anhydride, 9*92 silica, 9*36 carbonic anhydride, 7'13 phosphoric 
 anhydride, 20*49 chloride of calcium, and 3 '63 chloride of sodium. 
 
 ACHIXiXiEXC ACID. An acid said to exist in millefoil (Achittea Millefolium). 
 It crystallises in colourless prisms, soluble in 2 parts of water at 12 '5. With the 
 alkalies it forms salts which are easily soluble in water, but sparingly in alcohol. The 
 solutions are precipitated by neutral acetate of lead, whereas the free acid is precipi- 
 tated by the basic acetate only. The potassium, sodium, and calcium salts are crys- 
 tallisable : the ammonium and magnesium salts dry up to amorphous masses. The 
 quinine salt is said to be obtained in fine crystals grouped in stars, when its aqueous 
 solution is mixed with alcohol, then boiled and left to cool slowly (Zanon, Ann. Ch. 
 Pharm. Iviii. 31). Neither the acid nor its salts have been analysed. L. G-melin, 
 (Handbook, x. 207) suggested that this acid might be impure malic acid. According 
 to Hlasiwetz (J. pr. Chem. Ixii. 429) it is aconitic acid. 
 
 ACHIXiliEXN. A bitter substance of unknown composition, extracted by Zanon 
 from millefoil. It forms a hard, yellowish brown extract, having a peculiar ocloxir and 
 bitter taste, easily soluble in water and in boiling alcohol, sparingly in cold alcohol 
 and insoluble in ether ; but on treating it with a few drops of any acid, it becomes 
 easily soluble in ether; it dissolves also in ammonia. It is said to be useful as a 
 remedy against fever. 
 
 ACHXRZTE. (See DlOPTASE.) 
 
 ACHIMCXTE. A mineral first distinguished by Strom. It has a brown-black or 
 red-brown colour on the outside, blackish or dark greyish green on the fractured sur- 
 faces; in thin fragments it is translucent, and exhibits a yellowish-brown colour. 
 Sp. gr. 3*43 to 3*53. Scratches glass. Melts to a black bead before the blowpipe. 
 It crystallises in oblique four-sided prisms with truncated lateral edges and very 
 sharp four-sided terminal faces, the edges of which correspond with the lateral edges 
 
ACHROITE-ACIDIMETRY. 37 
 
 of the oblique prism. It has four cleavages, two parallel to the sides of the oblique 
 prism, and the other two less obvious parallel to the truncations of the acute lateral 
 edges. According to the analyses of Berzelius and Rammelsberg, its composition is 
 XaO.SiO 3 * Fe 2 3 . 2Si0 3 (Si = 21 -5 . =8) or 2Na 2 0.3SiO' 2 + 2(Fe 4 3 ,3Si0 2 ) 
 (Si = 28-5 . = 16.) It occurs, though rarely, embedded in granite at Eger, and in 
 syenite, near Porsgund in Norway. 
 
 ACHROXTS. A name given to the colourless variety of tourmalin. 
 
 ACHTAHATtfDITE. A name given by Breithaupt to a doubtful mineral, 
 hitherto found only in decomposed crystals (trigonal dodecahedrons) which occur in 
 association with vesuvian from Vilui (viluite) : they are perhaps derived from helvin. 
 
 ACIBROIVIIDES, ACXCHXiORXXJQBS, &c. (See OxYBROMiDES, OXYCHLOJBIDES, 
 &c. &c.) 
 
 ACICUXiITE. (Acicular Bismuth, Needle ore,} a native sulphide of bismuth, con- 
 taining also sulphides of copper and lead. The formula assigned to it by Dana is 
 (SCtiS + BiS 3 } + 2(3PbS + BiS 3 ) showing it to be analogous to Bournonite, with 
 which it is isomorphous. 
 
 It occurs embedded in white quartz, and accompanying gold, at Beresof, in Siberia. 
 
 ACXDIMZZTRIT. The determination of the quantity of real acid in a sample of 
 hydrated acid, is a problem of frequent occurrence, both for scientific and for technical 
 purposes. As the specific gravity of a mixture of acid and water always increases 
 with the proportion of acid present, and as, moreover, a certain specific gravity 
 always corresponds to a certain strength, provided no foreign substances are present, 
 it follows that if the specific gravity corresponding to each particular percentage of 
 real acid has once been accurately determined and tabulated, the strength of any 
 given sample of aqueous acid may always be determined by taking its specific gravity 
 and referring to the tables. (See SULPHURIC, NITRIC, HYDROCHLORIC ACID, &c.) This 
 method is in fact much used, the density being generally taken with the specific gravity 
 bottle for scientific purposes, and with the hydrometer for commercial estimations. 
 This method, however, necessarily supposes that the acid is pure ; the presence of any 
 foreign substance, such as nitrate of sodium in nitric acid, cream of tartar and ex- 
 tractive or colouring matter in vinegar, &c. would altogether destroy the accuracy of 
 the result. Moreover, in some acids, the specific gravity varies so little for consider- 
 able difference of strength, that a very slight inaccuracy of observation entails a large 
 error in the result. In acetic acid, for example (p. 11), an increase of strength amount- 
 ing to 1 per cent, produces on the average, an increase of density not exceeding 
 0-0034. For these reasons it is essential, especially for technological purposes, to adopt 
 some ready and exact method of determining the strength of an acid, independently 
 of its specific gravity. 
 
 The strength of an acid may be estimated : 
 
 a. By Volumetric analysis, that is by ascertaining the measured quantity of a standard 
 alkaline solution required to saturate a given volume of the acid. (See ANALYSIS, VOLU- 
 METRIC.) 
 
 b. By Weight analysis. This mode of estimation might be conducted in various 
 ways : for instance, by converting a given quantity of the hydrated acid into a neutral 
 salt of potassium, sodium, barium, lead, silver, &c. either by saturation or precipita- 
 tion, weighing the salt thus formed, and calculating the quantity of acid from its 
 known composition. This method is indeed constantly adopted in scientific chemistry ; 
 but is for the most part too tedious for technical purposes. A quicker method is to 
 decompose a known weight of the acid with an excess of acid carbonate of sodium or 
 potassium, and estimate by weight the quantity of carbonic anhydride evolved. The 
 quantity of real acid in the sample of hydrated acid is then easily calculated ; for each 
 atom of a monobasic acid, expels 1 atom of carbonic anhydride (CO 2 = 44,) and each 
 atom of a dibasic acid expels two atoms of carbonic anhydride (2C0 2 = 88) : this 
 will be seen from the following equations : 
 
 For hydrochloric acid : 
 
 C0 8 NaH + C1H = CINa + CO 2 4- H 2 0. 
 
 CO 2 : C1H = 44 : 36-5 
 For acetic acid : 
 
 C0 3 NaH + C 2 H 3 2 .H = C 2 H 3 2 .Na + CO 2 + H 2 
 
 CO 2 : C 2 H 3 2 .H = 44 : 60 
 For sulphuric acid : 
 
 2C0 3 NaH + S0 4 H 2 = S0 4 Na 2 + 2C0 2 + 2H 2 
 2C0 2 : S0 4 H 2 = 88 I 98 =-- 44 : 49 
 
 Suppose, for example, that 13 P 5 grm. of hydrated sulphuric acid thus treated with 
 
 i) 3 
 
38 
 
 ACIDIMETRY. 
 
 Fig. 1. 
 
 acid carbonate of sodium, eliminate 1/4 grains of carbonic anhydride. The quantity 
 of real acid (S0 4 H 2 ) in the 12-5 grm. is then 1-4 x ~ = 1-47 grm. and the 
 
 44 
 
 quantity of real acid in 100 parts of the hydrated acid will be given by the equation : 
 
 * - " 7 x IFs - l0 ' 89 ' 
 
 A convenient apparatus for these determinations is a small light glass flask (fig. 1) of 
 aboutlOO cubic centimetres (3 or 4 oz.) capacity, having a lipped edge, and fitted with a 
 cork perforated with two holes. Into one of these apertures is fitted a bent tube #, carry- 
 ing a drying tube b, filled with chloride of calcium, and into the other, a narrow tube c, 
 reaching nearly to the surface of the liquid, and bent at an obtuse angle above the 
 cork. A convenient quantity of the acid whose strength is to be determined, having 
 been weighed out in the flask, a quantity of acid carbonate of sodium or potassium 
 more than sufficient to neutralise the acid, is placed in a small test-tube about an inch 
 long, and having its lip slightly turned over, so that it may be suspended by a thread, 
 This tube is then let down into the flask by the thread, but not low enough to come 
 in contact with the acid ; the thread is fixed in its place by inserting the cork into the 
 neck of the flask, and the whole apparatus is weighed. The orifice of the bent tube e, 
 is then closed with a plug of cork or wax, the cork of the flask loosened sufficiently to 
 allow the short tube t, containing the alkaline carbonate 
 to drop into the acid, and the cork immediately tightened. 
 The carbonate is now decomposed by the acid, and carbonic 
 anhydride escapes through the drying tube, the chloride of 
 calcium retaining any moisture that may be carried along 
 with it. When the effervescence ceases, the flask must be 
 warmed to ensure the complete removal of the carbonic 
 acid from the liquid, and after it has cooled, the plug must 
 be removed from the bent tube c, and air drawn through 
 the apparatus by applying the mouth to the extremity 
 of the chloride of calcium tube, in order to remove all the 
 carbonic anhydride remaining in the flask, and replace it 
 by air. The whole is then again weighed, and the loss of 
 weight gives the qiiantity of carbonic anhydride which has 
 escaped. At the completion of the experiment, a piece of 
 blue litmus paper must be thrown into the liquid in the 
 flask ; if it remains blue, the determination may be con- 
 sidered exact ; but if it is reddened, there is still free acid 
 in the flask, showing that the quantity of carbonate intro- 
 duced was not sufficient to decompose it. In that case, a second small tube containing 
 alkaline carbonate must be introduced as before, the apparatus again weighed, 
 and the whole process repeated. The second loss of weight added to the first, gives 
 the total quantity of carbonic anhydride evolved. 
 
 Another form of apparatus for these estimations, devised by "Will and Fresenius, is 
 shown in fig. 2. A and B are two small flasks, having strong necks turned over in a 
 
 lip. Each of them is closed with a tight-fitting 
 cork pierced with two holes. Through the cork of A 
 there passes a straight tube a, reaching nearly to 
 the bottom of the flask ; a tube c, bent twice at 
 right angles, passes through both corks, termi- 
 nating just below that of A, bat reaching nearly 
 to the bottom of the flask B ; a straight tube d 
 also passes through the cork of B, terminating just 
 below it. The tube a is closed at the extremity b 
 with a plug of wax. The acid to be estimated is 
 weighed out in the flask A ; the other flask B is filled 
 to about one-third with strong sulphuric acid ; and 
 the whole apparatus is connected in the manner 
 shown in the figure, the proper quantity of acid car- 
 bonate of sodium being introduced into A in a 
 short test-tube, suspended by a thread in the manner 
 described with the former apparatus. The whole 
 apparatus is then weighed, the cork a loosened, so 
 as to allow the tube containing the carbonate to fall into the acid, and the cork im- 
 mediately secured. Carbonic anhydride is now evolved, and is obliged to pass through 
 the sulphuric acid in B, whereby it is completely dried. As soon as gas ceases to 
 escape, the flask A is immersed in water at about 50 or 60 C. till the fresh 
 evolution of gas thereby occasioned ceases. The wax-} 'lug is then loosened, to 
 
 Fig. 2. 
 
ACIDS. 39 
 
 prevent the sulphuric acid in B from being forced into A, in consequence of diminished 
 pressure in that vessel ; the apparatus is removed from the hot water ; and air is 
 sucked through the tube d as long as any taste of carbonic acid is perceived. Lastly, 
 the apparatus, when quite cold, is re-weighed, and the loss of weight gives the quantity 
 of carbonic anhydride evolved. , 
 
 This apparatus is much heavier and more bulky than that before described, and 
 does not appear to possess any advantage over it. Mohr points out, as a source of 
 inaccuracy in its use, that the large surface of the two flasks, being heated during the 
 experiment, is not likely, on cooling, to condense exactly the same quantity of moisture 
 as was attached to it before. 
 
 It is of the utmost importance that the acid carbonate of sodium or potassium., used in 
 these determinations, be quite pure and free from neutral carbonate. The acid carbonates 
 give a white precipitate with chloride of mercury, and the neutral carbonates a red-brown 
 precipitate ; but this test will not indicate the admixture of a small quantity of neu- 
 tral carbonate with the acid carbonate. A more certain test of purity is to weigh out two 
 equal portions of the acid carbonate, ignite one in a platinum crucible, and determine the 
 quantity of carbonic anhydride given off from the other by the action of the acid in the 
 apparatus represented in jig, 2 (See ALKALIMETRY). The quantity of neutral carbonate 
 of sodium remaining after the ignition should be to that of the carbonic anhydride 
 evolved as 53 to 44 ; and that of the neutral carbonate of potassium to the carbonic an- 
 hydride as 69 : 44. 
 
 If the acid carbonate is not pure enough to give a white precipitate with chloride of 
 mercury, it should be at once rejected. Commercial acid carbonate of sodium, which will 
 stand that test, may be further purified by triturating it to a uniform powder, covering 
 it with an equal weight of cold distilled water, leaving it. for 24 hours, then washing 
 it two or three times on a filter with a small quantity of cold water, leaving it to 
 drain, and drying it by exposure to the air without heating. Acid carbonate of potassium 
 may be purified by recrystallisation. (For further details on Acidimetry, see Dic- 
 tionary of Arts, Manufactures, and Mines, new edition, vol. i. p. 23.) 
 
 ACIDS. Salts of hydrogen. The following properties are common to the most 
 important acids, 
 
 1. Solubility in water. 
 
 2. A sour taste. (In those acids which possess the most strongly marked characters, 
 
 this property can be perceived only after dilution with a large quantity of 
 water.) 
 
 3. The power of reddening most organic blue and violet colouring matters (for ex- 
 
 ample, litmus), and of restoring the original colour of substances which have 
 been altered by alkalis. 
 
 4. The power of decomposing most carbonates, causing effervescence. 
 
 5. The power of destroying, more or less completely, the characteristic properties of 
 
 alkalis, at the same time losing their own distinguishing characters, and 
 forming alkaline salts. 
 
 The last is the only one of these properties which can be considered essential to 
 acids ; indeed, comparatively few acids possess them all. Moreover, there are many 
 substances which possess, in a greater or less degree, all these properties, but which 
 are never included among acids ; of these it will be sufficient to mention alum (sulphate 
 of potassium and aluminium). Alum is soluble in water ; its solution has a taste 
 which, though not purely sour, approaches much more nearly to sourness than that of 
 many acids (benzoic acid, for example) ; its solution also reddens litmus, causes brisk 
 effervescence with alkaline carbonates, and neutralises completely the alkalinity of 
 potash or soda, forming an alkaline sulphate. 
 
 In order to get a more exact idea of what it is which essentially constitutes acidity, 
 it may be useful to consider briefly the opinions which have successively been held 
 upon the subject by the chemists of past times. 
 
 In ordinary language, acid is equivalent to sour ; and in both Greek and Latin, the 
 idea of "sourne.-s" was expressed by almost the same word as that used for "vinegar," 
 the only acid known to the ancients (thus, Gr. 6vs, sour; ous, vinegar: Lat. acidus, 
 sour ; acetum, vinegar). It does not, however, appear that very great importance was 
 at any time attached to sourness as a characteristic of acids from a chemical point of 
 view. The number of known acids was first increased by the labours of the Arabian 
 chemists * ; and the solvent power which many of them exert on substances which 
 are insohible in water, seems first to have caused them to be regarded as a special 
 class of substances. Thus, Geber (middle of the eighth century), who was acquainted 
 
 * Almost all the historical statements containod in this article, for which no reference is given, are 
 nude on the authority ol Kopp, " Gesdiithte tier Chcmie," 4 vols. 8vo. Brunswick, 1843 - 47. 
 
 D 4 
 
40 ACIDS. 
 
 with nitric acid and with an impure kind of sulphuric acid, speaks of these bodies 
 under the common name of aqiue dissolutivce. The idea of corrosiveness, or at 
 least a kindred idea, which may perhaps be expressed with tolerable accuracy as that 
 of chemical activity, seems to have been long connected by chemists with the idea of 
 acidity. For example; Van Helmont (lived 1577 to 1644) attributed the active 
 properties of quick-lime to a peculiar acid, which he supposed limestone to obtain from 
 the fire during burning. Stahl (lived 1660 to 1734), who supposed the earths and 
 alkalis to have the same qualitative composition (see Art. ALKAU), represented the 
 alkalis as containing, in larger proportion than the earths, an acid principle to which 
 they owed their greater chemical activity; and even as lately as 1764, a similar idea 
 to that of Van Helmont was applied by M eye r to explain a large number of phenomena. 
 This chemist endeavoured to explain the different properties of the caustic and car- 
 bonated alkalis and alkaline earths, by supposing the former to be combinations of the 
 latter with a substance which he called acidum pingue (fatty acid), because, as he 
 thought, fat-like properties could be perceived by the sense of touch in its combinations 
 with alkalis (caustic alkalis). The idea that corrosiveness is the most important cha- 
 racteristic of acids, was also plainly uppermost in the mind of Lemery, when (1675) 
 he attributed the properties of acids to a sharp-pointed form of their smallest particles. 
 
 That the properties of acids are, in some important respects, opposed to those of 
 alkalis, was perceived at a comparatively early period. This opposition of properties 
 was in fact the basis of the medical theory of the latro-chemists (from the first quarter 
 of the 16th century to the middle of the 17th century). According to them, the con- 
 stituents of the human body had, some of them an acid, the rest an alkaline nature ; 
 the undue preponderance, or want of acidity or of alkalinity was the cause of disease, 
 the condition of perfect health being a particular relation between these two opposing 
 qualities. Otto Tachenius, a chemist of this school, gave, in 1668, as the essential 
 character of an acid, its power of combining with alkalis to form salts ; and accord- 
 ingly he included silica among acids. Boyle was well acquainted with the properties 
 which are now considered most distinctive of acids. He characterised acids by the 
 solvent power which they exert on various substances with various degrees of energy ; 
 by their power of precipitating sulphur and other substances from solution in alkali ; 
 by their power of changing the blue colour of many plants to red, and the red of many 
 others to bright red, and of bringing back to their original colour those which have been 
 changed by alkali ; and lastly by their forming with alkalis so-called neutral salts, at 
 the same time losing the properties just mentioned. This enumeration of the dis- 
 tinctive qualities of acids differs in no important respect from that given at the be- 
 ginning of this article. 
 
 Various suppositions have been made, from time to time, in order to account for the 
 properties possessed in common by the most strongly marked acids. In order to un- 
 derstand these, it must be borne in mind that the distinction which most chemists are 
 now accustomed to make between acids and salts, dates only from the time of La- 
 voisier, that is, from the end of the last century ; and that, till his time, acids, alkalis, 
 and the substances now by preference called salts, were all included under the common 
 term salts. But since the acids then known were comparatively few, and, as was 
 natural, were those of which the acid properties are most evident, the apparent dif- 
 ference between acids and other salts was much greater then than it is now. 
 
 The first theory of the constitution of acids was proposed by Becher in his " Physica 
 Subterranea," published in 1669. He attributed the common properties of acids to 
 their containing a common principle of acidity (acidum primigenium\ formed by the 
 union of primitive earth * and water, and supposed that the distinguishing characters 
 of each acid were due to the particular substance which it contained mixed with the 
 primitive acid. 
 
 The ideas of Lemery regarding acids have already been referred to. 
 
 He was followed by Stahl, who, in 1723, revived and extended Becher's theory. 
 The following may be taken as a summary of Stahl's views: The essential pro- 
 perties of all saline substances are : to affect the sense of taste, or to have sapidity ; 
 to be soluble in water ; and with regard to other chief properties, such as specific 
 gravity and fixity, to be intermediate between water and pure earth. In some salts 
 the saline properties are very marked, in others they are less prominent, and in some 
 they are barely perceptible. Those substances which are most saline, acids and 
 alkalis, have a great tendency to combine with bodies which have not saline pro- 
 perties, and to impart such properties to them. Hence we may conclude that some 
 substances are in themselves essentially saline, while others exhibit saline properties 
 merely because they contain a substance essentially saline as one of their constituents. 
 
 * According to Becher there were three pri 
 mercurial, which were the cau 
 corresponding to what the alch 
 
 j were three primitive earths, the vitrifiable, the combustible, and the 
 auses respectively of fusibility, of combustibility, and of volatility ; thus 
 itmuts understood by salt, sulphur, and mercury. 
 
ACIDS. 41 
 
 "We must regard as belonging to the former class those bodies which not only 
 possess saline properties (taste, solubility, &c.) but which can impart these properties 
 to other bodies by combining with them, and which, when separated from their 
 combinations, recover their original qualities. Hence, all acids and alkalis, fixed and 
 volatile, liquid and solid, must be considered as essentially saline. But, comparing 
 these bodies among themselves, we find that even they possess saline properties in very 
 various degrees. It appears, therefore, that there is only a very small number of actual 
 pr-imitive salts, or rather that there is only one such substance, which is a constituent 
 of all other saline bodies, and is the cause of their saline properties. It is obvious 
 that this substance must be sought among bodies which most distinctly and most 
 invariably manifest saline properties, and which are, at the same time, most simple in 
 their composition. Following this rule, we may at once exclude neutral salts, as being 
 resolvable into more simple saline substances ; again, alkalis are more subject to 
 alteration and to loss of their saline properties than acids ; they must, therefore, be 
 excluded. Of acids, we may select mineral acids as the most energetic. Lastly, of all 
 mineral acids, vitriolic (sulphuric) is the most active, has the greatest solvent powers, 
 adheres most forcibly to the matter dissolved, is the most deliquescent, &c. &c. Ac- 
 cordingly, acids must be considered as the basis of all other saline bodies, and vitriolic 
 acid as the basis of all acids. (Macquer's Dictionnaire de Chimie [1st. Edit, pub- 
 lished anonymously, Paris, 1766] Articles " Acide" and "Sel; " Kopp, iii. 15 ; also 
 Encyclopedic, ou Dictionnaire raisonne des Sciences, des Arts, et des Metiers, * * 
 mis en ordre et public par MM. Diderot et D'Alembert, t. xiv. [Neufchatel, 1765] 
 Article " Sel et Sels." The chemical part of this work was by Malouin). 
 
 Such were the ideas respecting acids and the cause of acidity, which, with unim- 
 portant variations, were held by almost all chemists until the rise of the antiphlogistic 
 system of chemistry. (See COMBUSTION.) But before the downfall of the older 
 system, chemists had begun to have more exact notions than formerly of what were 
 elementary bodies, and to feel the necessity of considering as elements all bodies which 
 they could not decompose. Hence, although Stahl regarded sulphuric acid as a 
 secondary principle, formed by the union of the primitive principles of earth and 
 water, and the other acids as compounds of sulphuric acid with various substances, 
 many of the last upholders of the phlogistic theory regarded most of the inorganic 
 acids as simple substances. For instance, phosphoric and sulphuric acids were sup- 
 posed to be elements which, when combined with phlogiston, formed phosphorus and 
 sulphur respectively. Sulphurous acid was one of the few inorganic acids which were 
 regarded as compounds ; it was supposed to be sulphuric acid combined with less 
 phlogiston than was needed to convert it into sulphur ; or, what was the same thing, 
 to be sulphur deprived of part of its phlogiston. 
 
 But all previous ideas about acids were gradually superseded by those of Lavoisier. 
 Having found, experimentally, that carbonic, nitric, phosphoric, sulphurous and sul- 
 phuric acids, all contained the then newly-discovered substance oxygen (discovered 
 August 1st, 1774), Lavoisier concluded that oxygen was a constituent of all acids, 
 that it was the acidifying principle. (Lavoisier, Traite elementaire de Chimie 
 (1st edit. 1789), i. 69 et passim; Kopp, i. 308; also iii. 17.) 
 
 He first proposed this theory of acids in 1778 ; and, although acids were known in 
 which no oxygen could be detected, nearly all chemists continued for about thirty 
 years to consider the assumption, that acidity was in every case due to the presence of 
 oxygen, as a necessary part of the antiphlogistic doctrine. Berthollet, indeed, as early 
 as 1789, pointed out that hydrosulphuric and prussic acids contained no oxygen; but 
 it was not till about 1810, after Davy's and G-ay-Lussac and Thenard's researches on 
 muriatic and oxy-muriatic acids (hydrochloric acid and chlorine) that chemists generally 
 began to admit the existence of acids free from oxygen. The conclusions drawn from 
 these experiments were confirmed by G-ay-Lussac's discovery of hydriodic acid in 1814, 
 and by his examination of prussic acid in 4 1815. From this time, most chemists re- 
 cognised two classes of acids those containing oxygen (oxygen-acids), and those 
 containing no oxygen (hydrogen acids). Attempts, however, were still made to dis- 
 cover a constituent common to all acids, to which their common properties could be 
 ascribed. Thus, on the one hand, Berzelius continued till 1820 to assert the necessary 
 existence of oxygen in all acids ; while, on the other hand, some chemists maintained 
 that all acids contained hydrogen as an essential constituent. 
 
 The latter opinion was advocated by Davy. His ideas about acids appear to have 
 been essentially the following.: No one substance ought to be regarded as the acidi- 
 fying principle ; the chemical properties of acids, as well as of other bodies, depend 
 not only on the nature of their constituents, but also on their corpuscular arrangement. 
 The so-called hydrated acids are the only true acids, and have a constitution similar 
 to that of their salts. Hydrated chloric acid is a ternary compound of chlorine 
 oxygen, and hydrogen, analogous to chlorate of potassium, which is a ternary compound 
 
42 ACIDS. 
 
 of chlorine, oxygen, and potassium. The whole of the oxygen may be removed from the 
 acid, and it will remain acid ; the whole of the oxygen may be removed from the neutral 
 salt, and it will remain neutral. We have no proof that in either of these bodies 
 the oxygen ^is divided between the chlorine and the other constituent, or that either of 
 them contains so-called anhydrous chloric acid. Similarly, there is no proof that sul- 
 phates or nitrates contain anhydrous sulphuric or nitric acid. Hydrated sulphuric and 
 hydrated nitric acids are the true acids, and are ternary compounds, like the sulphates 
 and nitrates. (Davy, Journal of Science and the Arts, i. 285 288; also Gilbert's 
 Annalen, liv. 377381 ; Phil. Trans. 1815, 212, 213; 218, 219; also Kopp.) 
 
 In 1816 Dulong proposed the theory, since known as the binary or hydrogen-theory 
 of acids. He endeavoured to show that all acids were similar in constitution to hy- 
 drochloric acid ; that they were all compounds of hydrogen with a radicle which was 
 in some cases simple (as in hydrochloric and hydriodic acids), in other cases compound 
 (as in hydrocyanic, oxalic, sulphuric, and nitric acids). His view of the constitution 
 of these acids may be expressed by the following formulae : 
 
 Hydrochloric acid H (Cl) 
 
 Hydriodic H (I) 
 
 Hydrocyanic H (CN) or H(Cy) 
 
 Oxalic H(C*0*) 
 
 Sulphuric H (SO*) 
 
 Nitric H(N0 6 ) 
 
 Salts, according to this theory, were represented as compounds of an acid-radicle 
 with a metal instead of with hydrogen ; thus : 
 
 Hydrochloric acid . . H (Cl) 
 
 Nitric acid . . . H (NO 6 ) 
 
 Chloride of potassium . K (Cl) Nitrate of potassium . K (NO 6 ) 
 
 Dulong's theory resembled Davy'<* in so far as it restricted the term acid* to sub- 
 stances containing hydrogen (hydrated acids), and assigned an analogous constitution 
 to acids and their salts, but differed from Davy's theory in representing the atoms of 
 every acid as arranged in a specific manner : namely, all the atoms except hydrogen 
 as grouped together to form a compound radicle. 
 
 -These views did not attract much attention till they were applied by Liebig, in 
 1837, to explain the constitution of several organic acids, and of the various modifi- 
 cations of phosphoric acid (Ann. Ch. Pharm. xxvi. 170 ; Ann. Ch. Phys. Lxviii. 70.), 
 and although they are explained and discussed in a large proportion of the Manuals 
 of Chemistry published during the fifteen or twenty years following that date, they 
 have never been generally adopted. Until a comparatively recent date, almost all 
 chemists continued to regard oxygen-acids as a class of bodies essentially distinct from 
 hydrogen-acids and from metallic salts. Confining the name of oxygen-acids to the 
 substances now known as ANHYDRIDES, they regarded oxygen-salts as bodies formed 
 by the direct union of acids with metallic oxides, and recognised no essential distinc- 
 tion between actual hydrated acids (acids in the sense of Davy and of Dulong) and 
 mere solutions of the anhydrides in water. 
 
 An important extension in the then existing views respecting acids resulted from 
 the discovery announced by Berzelius, in 1826 (Berzel. Jahresb. vi. pp. 184etseq.), 
 that certain metallic sulphides, such as those of arsenic and antimony, were capable 
 of imiting with the alkaline sulphides so as to form well-defined salts perfectly 
 analogous to those formed by the combination of the corresponding metallic oxides 
 with the alkalis. From this time, the existence of three new classes of acids (and 
 corresponding salts) was recognised, namely, acids in which the oxygen of ordinary 
 acids was replaced by sulphur, or by the analogous elements, selenium and tellurium. 
 
 We owe the ideas of the nature of acids, now very generally entertained, chiefly 
 to the advance of organic chemisty, which has brought to light a very large number, not 
 only of new acids, but of new substances of all kinds, whose chemical relations cannot be 
 adequately expressed upon the system formerly universally adopted, of regarding all 
 
 * Notwithstanding the more strict use, which was made by both Davy and Dulong, of the word 
 acid, very many chemists still use it to express bodies belonging to two very different classes : acids and 
 anhydrides. Thus the bodies HC1, UNO 3 . H 2 SCM, N^O 5 , SO 3 are all of them frequently called acids, 
 although the first three possess marked resemblances among themselves and equally marked differences 
 from the other two. Again, the bodies H 2 SO 4 and SO 3 are often called by the same name, sulphuric 
 acid, although they cannot be obtained in any case by the same process, and although, when caused to 
 act upon one and the same substance, they almost always give rise to products essentially unlike. This 
 confusion between acids and anhydrides dates from the earliest knowledge of the latter class of bodies, 
 and was caused by the fact that the anhydrides which were first discovered immediately produce acids 
 when thev come in contact with water. Thus, Lavoisier, by burning phosphorus in oxygen, obtained pirns- 
 phori anhydride, but since the solution of this substance in water contained phosphoric ;icid, he suppo-ed 
 the anhydride to be the acid, and regarded the real phosphoric acid as a combination of phosphoric acid 
 and water. Similarly, sulphuric acid was looked upon as containing "dry sulphuric acid" (sulph <ne 
 anhydride) and water ; and all other acids, even those of which the anhydrides were unknown, as nitric 
 and hydrochloric acids, were, in like manner, regarded as compounds ol a hypothetical anhydride (often 
 called "real acid ") with water. 
 
ACIDS. 43 
 
 compound bodies as formed by the union of two molecules possessing opposite electro- 
 chemical characters, or of two groups, which, in their turn, hare a similar binary consti- 
 tution. Among the new theories which were the earliest to be thus introduced into the 
 science, was the " Theory of Chemical Types," which represented chemical compounds 
 as combinations of the elementary atoms held together by the attraction exerted by 
 each atom upon all the rest, and capable of exchanging one or several atoms of one 
 element for an equal number of atoms of another, so as to produce new substances, 
 built up after the same plan or type as the original compoiinds, though one or more 
 of their atoms was of a different nature. According to this "view, acids and metallic 
 salts were regarded as bodies of the same class : each acid and its corresponding 
 salts were regarded as compounds formed upon the same type, and differing only 
 from the fact of the acid containing hydrogen in the place of the metal contained 
 in the salts. It will be seen that this manner of representing the mutual relation of 
 acids and salts differed but little from that of Davy. 
 
 Another result of the progress of organic chemistry which helped to modify the 
 older notions on these subjects, was the acquisition of more consistent ideas than had 
 previously existed of the relative weights of different substances which are chemically 
 comparable with each other. Thus it was discovered that an atom of water con- 
 tained twice as much hydrogen as an atom of hydrochloric acid, and therefore, that 
 the so-called monobasic acids, or acids containing the same quantity of hydrogen as 
 hydrochloric acid, could not be compounds of water with anhydrous acids, as had been 
 hitherto supposed. The discovery by G-erhardtin 1852 (Ann. Ch. Phys. xxxvii. 
 285) of the anhydrides corresponding to several monobasic acids, and the fact of their 
 atomic weights being found to be double the atomic weights of the hypothetical 
 anhydrides of the older theory, confirmed the same conclusion. 
 
 It is now clear that acids do not form a class apart, distinguished from other sub- 
 stances by something essentially different in their nature ; they are, on the contrary, 
 nothing more than a particular class of salts. The definition of acids as salts of 
 hydrogen, first clearly enunciated by Gferhardt*, and repeated at the head of this 
 article, is an accurate statement of the relations which exist between acids and other 
 chemical substances. This definition is, however, obviously insufficient, without 
 a previous answer to the question what is a salt ? For this we must refer to the 
 article SALT. In that article also the properties which acids possess in common with 
 other salts, and which characterise them as belonging to that class, will be most suit- 
 ably discussed. In the remainder of this article we shall consider the distinguishing 
 properties of acids as such, and the mutual relations of the principal classes into 
 which acids may be divided. 
 
 The mode in which acids most frequently react with other substances is by double 
 decomposition, in which they exchange their hydrogen for metals, or for radicles 
 possessing, to a certain extent, metallic functions. The following reactions are all of 
 this kind : namely, their reactions 
 
 1 With metals, 
 
 Zn 2 + H 2 S0 4 = H 2 + Zn 2 S0 4 . 
 2 With metallic oxides, sulphides, and salts generally, 
 
 KEO + HC1 = H 2 + KC1 
 
 KHS + HC1 = H 2 S + KC1 
 
 Pb 2 -h 2HC1 = H 2 O + 2PbCl 
 
 Fe 2 S + H 2 S0 4 = H 8 S + Fe 2 S0 4 
 
 2NaCl + H-SO 4 = 2HC1 + Na 2 S0 4 
 
 KNO 3 + H 2 SO* = HNO 3 + KESO 4 
 3 With the hydrates of alcohol-radicles, 
 
 C-IP.H.O + HC1 = H 2 + C 2 H 5 C1. 
 
 Hydrate of Chloride of 
 
 ethyl. ethyl. 
 
 4 With, various metallic compounds, 
 
 C 2 H 3 Zn + HC1 = C 2 H 5 .H + ZnCl. 
 
 Zinc-ethyl. Hydride of 
 
 ethyl. 
 
 KH 2 N + HC1 = H 3 N + ZC1: 
 
 Potassamiue. 
 
 * Precis de Chimie organique (Paris, 18 4) i. 70; Introduction fa 1'etude de la Chimie par le Systeme 
 Umtaire ( Paris, 1848), 103. On the similar characters of acids, or hydrogen-salts, and of metallic salto 
 in general, and on the important differences between them and the anhydrides, comp. Laurent, McthoUe 
 tie Chimie, pp. 48- 5G, or Cavendish Society's translation, pp. 3U to 45. 
 
44 ACIDS. 
 
 With some substances acids unite directly : namely 
 1 With ammonia and its analogues, 
 
 NH 2 + HC1 = NH 4 C1 
 PH 8 + HI = PH 4 I 
 2NC 6 H 7 + H 2 SO* = (NC 6 H 7 ) 2 .H 2 SO*. 
 
 Aniline. Sulphate of aniline. 
 
 2 With some hydrocarbons, 
 
 C 2 H 6 S0 4 
 
 HC1 
 
 Propylene. 
 
 Keactions such as the above can be produced by all well characterised acids. Th 
 majority of acids can also produce other reactions of various kinds, some of which are 
 characteristic of individual acids, while others are common to a considerable number, 
 and therefore serve for their division into classes. The rational formulae by which 
 the various acids are commonly represented, indicate the nature of their leading 
 reactions, and hence to the class to which they belong. 
 
 Oxygen-acids form by far the most numerous and important class of acids. We 
 may take acetic acid as a special example, and show how the double decompositions 
 which it is capable of undergoing, in common with the other acids of this class, lead to 
 the choice of the rational formulae by which oxygen-acids in general are usually re- 
 presented. 
 
 1. When acetic acid is converted into an acetate by acting upon it with an oxide, 
 metal, or any other substance, it loses hydrogen. This may be represented by writing 
 one atom of hydrogen in its formula apart from the rest : C 2 H 4 2 = C'-'H 3 2 ,H. 
 
 2. By perchloride of phosphorus acetic acid is converted into chloride of acetyl, and 
 loses one atom of oxygen and one atom of hydrogen. To express this, we must 
 write the formula of acetic acid thus ; C 2 H 3 O.HO. 
 
 3. By the action of pentasulphide of phosphorus, acetic acid loses half its oxygen, 
 and becomes thiacetic acid, 5(C 2 H 4 2 ) + P-S 5 = 5(C'-H'OS) + P 2 5 . 
 
 The rational formula derivable from this reaction is C'-H'O.O. 
 
 Combining these three expressions, we coine to divide the formula of acetic acid 
 
 into three parts H, C 2 H 3 and 0, and to write it 0, or H.C 2 H 3 O.O, or in some 
 
 similar way. This formula indicates beforehand all the most frequent double de- 
 compositions of which acetic acid is capable ; viz. the separation of one atom of 
 hydrogen, the other atoms remaining together (formation of acetates) ; the separation 
 of one atom of hydrogen and one atom of oxygen, leaving the group C 2 H 3 (forma- 
 tion of chloride of acetyl, of acetamide &c.) ; the separation of one atom of oxygen, 
 leaving the remaining atoms combined (formation of thiacetic acid, &c.) 
 
 The large number of acids which resemble acetic acid as to their leading double 
 decompositions, receive similar rational formulae ; that is to say, rational formulas con- 
 sisting of three parts: namely (1) one or more atoms of hydrogen, (2) one or more 
 atoms of oxygen or sulphur, (3) a radicle, nearly always compound and containing 
 oxygen, sulphur or a similar element. Thus, writing the rational formula of acetic acid 
 
 H ' we write that of benzoic acid H ' of P) acid 0, of 
 
 /"I2f\2 "PO f^2TT3O 
 
 oxalic acid -g- 2 O 2 , of phosphoric acid jp O s > of thiacetic acid H S, of sulpho- 
 
 /~1Q< fTO" PI 
 
 carbonic acid TT 2 S 2 , of sulphocyanic acid JT S, of hypochlorous acid Vr 0. 
 
 If in any of these formulae we replace the radicle by its equivalent quantity of hydro- 
 gen (see EQUIVALENTS) and the sulphur (where it occurs) by its equivalent of 
 
 TT TT2 
 
 oxygen, we obtain the formula of one, two, or three, atoms of water TT 0, jT 2 O 2 , 
 
 TT3 
 
 or r 3 O 3 . Moreover, the decompositions of which water is susceptible are essentially 
 
 quite similar to those of acetic acid. Thus, when converted into a hydrate by the ac- 
 tion of a metal or of an oxide, water loses one atom of hydrogen K + H 2 O = H V HKO, 
 or Ca 2 + H 2 = CaHO + HCaO ; oxychloride of phosphorus converts water into 
 hydrochloric acid, removing from it one atom of hydrogen and one atom of oxygen. 
 
ACIDS. 45 
 
 3H 2 + POCP = 3HC1 + P0 4 H 3 ; lastly, pentasulphide of phosphorus converts it 
 into hydrosulphuric acid, removing from it one atom of oxygen : 5H 2 + P 2 S 5 = 
 dH 2 S + P 2 5 . It is in this sense that water is taken as the type, or standard of 
 comparison for acetic acid and all other acids which undergo similar double decom- 
 positions. 
 
 Another class of acids are, in the same way, referred to the type hydrochloric acid, 
 HC1. These acids are susceptible of only one kind of double decomposition :_ their 
 atoms are separable into only two groups, hydrogen and a radicle. Hydrobromic acid 
 HBr, hydriodic acid HI, hydrocyanic acid HCN, are of this class. 
 
 There is still a third class of acids which may be referred to the type ammonia, 
 NH 3 . Succinimide, C 4 H 5 N0 2 , cyanic acid (carbimide), CONH, and sulphocyanic acid 
 (sulphocarbimide), CSNH, are acids of this kind. Under the influence of metallic 
 oxides, and hydrates they part with one atom of hydrogen, and take up in exchange 
 an atom of metal : 
 
 H 2 0. 
 
 2(C 4 H 5 N0 2 ) + Ag 2 = 2(C 4 H 4 AgN0 2 ) + 
 
 Succinimide. Argento-succini- 
 mide. 
 
 CHNO + HKO = CKNO + H 2 0. 
 
 Cyanic 
 acid. 
 
 . 1 
 
 Cyanate 
 of potassium. 
 
 When boiled with dilute acids, they break up into two groups, a carbonised radicle 
 on the one hand (which combines with oxygen or with oxygen and hydrogen derived 
 from the water of the dilute acid), and the group HN (which combines with two atoms 
 of hydrogen) on the other hand. 
 
 CHNO + H 2 = CO.O + HN.H 2 . 
 
 Carbonic Ammonia 
 anhydride. 
 
 2H 2 = C 4 H 4 2 .H 2 2 + HN.H 2 
 
 Succinimide. Succinic acid. 
 
 These reactions show that the rational formulae of these acids must consist of three 
 parts : an atom of nitrogen, an atom of hydrogen, and a radicle composed of the 
 
 ( C 4 H 4 2 
 remaining atoms. Thus the formula of succinimide must be N.H.C 4 H 4 2 or N j ^ 
 
 that of cyanic acid N.H.CO, or N $^. The substance called by Gerhardt nitride of 
 
 benzoyl, sulphophenyl and hydrogen (C 13 H n S0 3 N) is another acid deriving from the 
 type ammonia. Its decompositions have not yet been much studied, but its be- 
 haviour with metallic oxides and its formation from ammonia by the successive action 
 of the chlorides of sulphophenyl and of benzoyl (C 6 H 5 S0 2 C1 and C'H'OCl) require that 
 its rational formula should be composed of the four parts N, H, C"H 5 S0 2 and C 7 H 5 0. 
 Since the constituent atoms of this acid are separable into four groups, it is evidently 
 susceptible of undergoing even more numerous decompositions than either the acids 
 deriving from the type H 2 0, or those previously mentioned as deriving from the type 
 NH 3 , whose atoms are separable into only three groups. 
 
 In regard to their chemical constitution, we may thus divide acids into' three prin- 
 cipal classes, which have the same mutual relations of formation and decomposition 
 as hydrochloric acid*, water, and ammonia, and which may therefore be regarded as 
 deriving from these bodies as types. 
 
 But, in the same sense as some of the acids which we have been considering, are 
 formed from two, or from three atoms of the same type (from H 2 C1 2 , IPO 2 , H 6 3 , &c.), 
 there are certain others which are formed from two or more atoms of two (or perhaps 
 three) different types ; for example, sulphuric acid S0 4 H 2 , derives from the type 
 
 O 2 , thus ( S 2 /' | O 2 , while sulphamic acid, S0 3 H 3 N, and chlorhydrosulphuric acid, 
 S0 3 HC1, derive respectively from the double types ]^j and^ j; thus ^ S 2 ^ 3 Q j 
 
 = sulphamic acid; ^ TT o ( ~ c ^ or ^ 1 y^ rosll ^P^ lur i c ac ^ Acids of this kind may 
 be called, for the sake of distinction, intermediate acids. The so-called amic acids 
 (see AMIC ACIDS) afford the most numerous and best known illustrations of this 
 
 * Since the reactions of the acids of the first class are also possessed by those of the second and third 
 classes, it is plain that, if we have regard to these reactions only, all acids may be referred to the type 
 hydrochloric acid. To. this extent, but no further, the hydrogen -theory represents correctly the con- 
 stitution of all acids. 
 
46 
 
 ACIDS. 
 
 class. Like sulphamic acid, they derive from the type TT 2 Q [ They can give rise to 
 
 two kinds of double decomposition ; that is, they can decompose either as hydrates 
 (derivatives of water), or as amides (derivatives of ammonia), according to the nature 
 of the body with which they react. In like manner, chlorhydrosulphuric acid and 
 analogous substances can decompose either as hydrates or as chlorides (derivatives of 
 hydrochloric acid). 
 
 Another way in which acids may be classified has reference to their basicity : they 
 maybe divided into monobasic, dibasic, and tribasic* acids. Graham was the first 
 to call attention to the existence of polybasic acids in his paper on arsenic and phos- 
 phoric acids (Phil. Trans. 1833, 253; Phil. Mag. iii. 451, 469). The distinctions 
 which he established between monobasic and polybasic acids, had reference merely to 
 the composition of their salts. In 1837 Liebig (Ann. Ch. Pharm. xxvi. 138; Ann. 
 Ch. Phys. Ixviii. 35) showed that tartaric, citric, meconic, and some other organic 
 acids were polybasic, but he pointed out no new general characters of polybasic acids, 
 nor any new way of distinguishing them from monobasic acids. Grerhardt (Precis de 
 Chimie Organique (1844), i 71 84) was the first to connect the basicity of acids 
 with other facts than the composition of their metallic salts, and he and Laurent (Ann. 
 Ch. Phys. [3] xviii. 266; Methode de Chimie, 6276, or Cavendish Society's Transla- 
 tion pp. 50 62) first placed the question on its present footing. 
 
 Mono-, di-, and tri-basic acids may be defined, in a few words, as containing respec- 
 tively, one, two, and three atoms of hydrogen replaceable by other metals, or by com- 
 pound groups of analogous function. This definition, taken by itself, is, however, 
 obviously insufficient to decide the basicity of any particular acid, since, by properly 
 multiplying or dividing its formula, we can represent it as possessing whatever basicity 
 we please. Hence, before we can decide what the basicity of an acid is, we must 
 know its atomic weight, and conversely, in order to fix the atomic weight of an acid 
 we require to know its basicity : in other words, the determination of its basicity and 
 the determination of its atomic weight are the same thing. 
 
 To decide either of these points, we must take into consideration the general beha- 
 viour of the acid with other bodies, and the nature of its derivatives. The following 
 are the most important general differences shown by acids of different degrees of 
 basicity : 
 
 a. Each dibasic acid can 
 form two ethers; one of 
 them neutral, the other 
 acid. (Thus, sulphuric 
 acid forms sulphate of ethyl 
 and ethyl-sulphuric acid.) 
 Two volumes of the vapour 
 of the neutral ether con- 
 
 a. Each monobasic acid 
 can form but one ether. 
 This is neutral in its pro- 
 perties. Two volumes of its 
 vapour contain only one 
 volume of ethyl, or alcohol- 
 residue. Monobasic acids 
 do not form acid ethers. 
 
 b. Monobasic acids cannot 
 form stable, well-defined 
 acid salts, or salts with 
 two or more metallic bases. 
 
 c. Monobasic acids cannot 
 form double or multiple 
 ethers, that is, ethers con- 
 taining two or more kinds 
 of alcohol-residue. 
 
 tain two volumes of ethyl 
 or alcohol-residue. 
 
 b. Dibasic acids can 
 form, with each metallic 
 base, a neutral salt and an 
 acid salt, which last is 
 exactly intermediate in 
 composition betweeen the 
 neutral salt and the free 
 acid. They can also form 
 well-defined double salts 
 containing two metallic 
 bases, as well as hybrid 
 salts containing two or 
 more metallic bases in in- 
 definite proportions. 
 
 c. Dibasic acids can form 
 double ethers, that is, 
 ethers containing two kinds 
 of alcohol-residue. (Ex- 
 ample, double oxalate of 
 ethyl and methyl.) 
 
 a. Each tribasic acid can 
 form three ethers ; one of 
 them neutral, the other two 
 acid. (e.g. phosphoric acid 
 forms phosphate of ethyl 
 and monethyl- and diethyl- 
 phosphoric acids.) Two vo- 
 lumes of the vapour of the 
 neutral ether contain three 
 volumes of alcohol-residue. 
 
 b. Tribasic acids can form 
 three salts with the same 
 metallic base, two of them 
 acid, and one neutral. 
 They can also form double, 
 triple, and hybrid salts. 
 
 * It is probable that tetrabasic acids also exist, but none have yet been much Investigated : pyro- 
 phosphoric and silicic acids seem to be such. 
 
ACIDS. 
 
 47 
 
 The above distinctions apply to acids of all kinds, from whatever type they derive. 
 The following apply only to acids which derive from the type water (oxacids). 
 
 d. Each monobasic oxacid 
 can form a chloride, in two 
 volumes of the vapour of 
 which is contained only one 
 volume of chlorine. Each 
 such chloride can take up 
 an atom of oxygen and an 
 atom of hydrogen in ex- 
 change for an atom of chlo- 
 rine to re-form the normal 
 acid, but there is no com- 
 pound intermediate in com- 
 position between the chlo- 
 ride and the normal acid. 
 
 e. Monobasic oxacids, by 
 reacting with ammonia, or 
 its derivatives, form neu- 
 tral amides, in two volumes 
 of the vapour of which is 
 contained only one volume 
 of nitrogen. There are no 
 compounds intermediate be- 
 tween these amides and the 
 corresponding acids. 
 
 d. Each dibasic oxacid 
 can form a chloride, in two 
 volumes of the vapour of 
 which are contained two 
 volumes of chlorine. Di- 
 basic oxacids can also form 
 chlorides which contain, 
 in two volumes of vapour, 
 only one volume of chlo- 
 rine, and are exactly inter- 
 mediate in composition 
 between the chlorides last- 
 mentioned and the normal 
 acids ; that is, they can 
 take up an atom of chlorine 
 in exchange for an atom of 
 oxygen and an atom of 
 hydrogen, to form chlorides 
 containing two volumes of 
 chlorine in two volumes of 
 rapour ; or they can take 
 up an atom of oxygen and 
 an atom of hydrogen in 
 exchange for an atom of 
 chlorine, to re-form the 
 normal acid. Thus, sul- 
 phuric acid, S0 4 H 2 , forms 
 chloride of sulphuryl or 
 chlorosulphuric aldehyde 
 S0 2 C1 2 , and the interme- 
 diate compound chlorhy- 
 drosulphuric acid, S0 3 HC1. 
 
 e. Dibasic oxacids, by 
 reacting with ammonia, or 
 its derivatives, form neu- 
 tral amides, in two volumes 
 of the vapour of which are 
 contained two volumes of 
 nitrogen. Intermediate in 
 composition between these 
 amides and the corre- 
 sponding acids are com- 
 pounds, generally acid 
 (amic acids), in two vo- 
 lumes of the vapour of 
 which is contained but one 
 volume of nitrogen. For, 
 example, oxalic acid, 
 C 2 4 H 2 , forms neutral ox- 
 amide, C 2 2 H 4 N 2 , and the 
 intermediate compound 
 oxamic acid C 2 3 H 8 N. 
 
 d. Each tribasic oxacid 
 can form a chloride in two 
 volumes of the vapour of 
 which are contained three 
 volumes of chlorine. 
 
 /. Monobasic oxacids' do 
 not form acid compounds 
 (so-called conjugate acids) 
 by reacting with hydro- 
 
 /. Dibasic oxacids form 
 acid compounds (conjugate 
 acids) by reacting with 
 hydrocarbons or other neu- 
 
 e. Tribasic oxacids, by 
 reacting with ammonia, or 
 its derivatives, form neu- 
 tral amides, in two volumes 
 of the vapour of which are 
 contained three volumes of 
 nitrogen. Intermediate in 
 composition between each 
 of these amides and the cor- 
 responding acid, there may 
 exist two acid compounds, 
 one monobasic and contain- 
 ing in two volumes of va- 
 pour two volumes of nitro- 
 gen : the other dibasic and 
 containing in two volumes 
 of vapour only one volume 
 of nitrogen. For example, 
 citric acid, C 6 H 8 7 , forms 
 with phenylamine (aniline) 
 neutral citrophenylamide, 
 C 6 H 8 4 Ph 3 N 3 , (Ph = C H H 5 = 
 phenyl), and the interme- 
 diate monobasic citrodiphe- 
 nylamicacid, C 6 H 8 5 Ph 2 N 2 ; 
 the dibasic citromonophe- 
 nylamic acid, C fi H 8 6 PhN, 
 has not yet been discovered. 
 
 f. Tribasic oxacids form 
 acid compounds by reacting 
 with hydrocarbons or other 
 neutral substances. For 
 
48 ACIDS. 
 
 carbons, or other neutral tral substances. For ex- example, phosphoric acid 
 substances. ample, sulphuric acid re- reacts with glycerin to form 
 
 acts with benzene to form phosphoglyceric acid. 
 
 sulphobenzidic (phenylsul- 
 
 phurous) acid, and with 
 
 glycerin to form sulpho- 
 
 glyceric acid. 
 
 (Compare Odling, Chem. Soc. Qu. J. xi. 127.) 
 
 In addition to these, other properties of acids might be mentioned, which are con- 
 nected more or less intimately with their basicity ; but, notwithstanding the number 
 of comparatively very well-defined characters which they severally possess, it is im- 
 possible to establish any absolute distinction between monobasic and dibasic, or between 
 dibasic and tribasic acids. There are many acids, which, in relation to a particulai 
 set of reactions, have the properties of monobasic acids, but, in relation to another set 
 of reactions, behave like dibasic acids ; others, again, appear from one point of view to 
 be dibasic, while from another point of view they seem to be tribasic. This will ap- 
 pear more distinctly by considering what degree of generality belongs to each of the 
 differences we have pointed out between acids of different basicities. 
 
 a. Number of ethers. Perhaps the only exception to this law is afforded by phospho- 
 rous acid, which forms three ethers, one of them containing, in two volumes of vapour, 
 three volumes of alcohol-residue, although, as regards its metallic salts, it is only 
 dibasic. 
 
 b. Number of metallic salts. Acetic and formic acids, which possess in a special 
 degree most of the characters of monobasic acids, form, each of them, two potassium- 
 and two sodium-salts. 
 
 c. Multiple ethers. No exception to this law is known so far as regards mono- and 
 di-basic acids. Tribasic acids ought by analogy to form ethers containing two or three 
 kinds of alcohol residue ; none such have yet been obtained, but there is no reason to 
 suppose that they might not easily be formed. 
 
 d. Number of chlorides. Some acids, which according to a, b, and c would be classed as 
 monobasic, form chlorides containing two volumes of chlorine, as well as intermediate chlor- 
 acids. For instance, Wurtz' s chlorured'acetylechlore, C' 2 H 2 CPO (Ann.Ch.Phys. [3] xlix. 
 60) reacts with one atom of water to form chloracetic acid, C 2 H 3 C10 2 ; and this, with 
 a second atom of water, forms glycollic acid, C 2 H'0 3 . These three bodies are there- 
 fore related in the same way as chloride of sulphuryl, chlorhydrosulphuric acid, and 
 sulphuric acid. Again, lactic acid, C 3 H 6 3 , a homologue of glycollic acid, is decom- 
 posed by pentachloride of phosphorus, giving chloride of lactyl, C 3 H 4 CPO, which re- 
 acts with alcohol to form chloropropionate (chlorhydrolactate) of ethyl, C 5 H 9 C10 2 , 
 (Wurtz, Ann. Ch. Pharm. cvii. 192) ; that is to say, the ether of an acid intermediate 
 between chloride of lactyl and lactic acid. The intermediate acid itself is produced 
 C 3 H 5 C10 2 , by the action of chloride of lactyl on water. (Ulrich. Chem. Soc. Qu. J. 
 xii. 23 ; Ann. Ch. Pharm. cix. 268.) So far then as their chlorides are concerned, 
 glycollic and lactic acids resemble dibasic and not monobasic acids. (See also ob- 
 servations on e.) 
 
 In the case of tribasic acids, no intermediate chloracids are known, such as would 
 correspond to chlorhydrosulphuric acid and other derivatives of dibasic acids. It is 
 probable that each tribasic acid can form two such compounds, that phosphoric acid 
 (PH 3 4 ), for example, can form chlorhydrophosphoric acid (PH 2 C10 3 ,) dibasic?) and 
 dichlorhydrophosphoric acid * (PHCPO 2 , monobasic ?) 
 
 e. Number and nature of amides. Some monobasic acids form amides containing, in 
 two yolumes of vapour, two volumes of nitrogen. For instance, acetic acid forms 
 acediamine, C 2 H 6 N 2 , between which and acetic acid C 2 H 4 2 , acetamide C 2 H 5 NG is 
 exactly intermediate, (just as oxamic acid, C 2 H 3 N0 3 , is intermediate between oxamide, 
 O'H 4 N 2 2 , and oxalic acid, C 2 H 2 4 ) ; acetamide, however, is neutral, not acid, in its 
 properties. 
 
 Certain other acids, generally considered monobasic, form amides containing one 
 atom of nitrogen, which possess some of the properties of acids. Thus glycollic acid, 
 C 2 H 4 3 , forms glycocoll, C 2 H 5 N0 2 , a substance capable of acting -as an acid, and pos- 
 sessing the same relation of composition to glycollic acid, that oxamic acid does to ox- 
 alic acid, or acetamide to acetic acid. The so-called benzamic, toluamic, cuminamic. 
 &c. acids, are substances of a similar constitution : they are to oxybenzoic, oxycuminic, 
 &c. acids what glycocoll is to glycollic acid. In short, glycollic and similar acids, 
 though in the strict sense monobasic are diatomic ; that is, they form but one salt 
 
 * Chlorhydrosulphuric acid is formed; when sulphuric anhydride is brought in contact with dry 
 hydrochloric acid (SO 3 +HC) = SHC1O 3 ). Similarly, a liquid, which probably contains one or both of 
 the compounds mentioned in the text, is formed when phosphoric anhydride is exposed to dry hydro- 
 chloric acid (P2O'+311C1 = PH2C10 3 +PHC1202_?) 
 
ACIDS. 49 
 
 with each metallic base are monobasic as regards their metallic salts, but resemble 
 dibasic acids so far as regards their other derivatives (chlorides and amides). 
 
 /. Formation of complex acids. The difference in respect of acidity between com- 
 pounds formed by the reaction of monobasic and of polybasic acids on neutral sub- 
 stances, is a particular case of a general rule which was first announced by G-erhardt 
 (Precis de Chim. Organ, i. (1844) 102 ; Compt. rend. Trav. Chim. 1845, 161) in the 
 following form ; B b' + b 1, where B denotes the basicity of the body resulting from 
 the the reaction, b .and b' the basicities of the reacting substances (the basicities of 
 alkaline or neutral substances, and of mono-, di-, and tribasic acids being estimated re- 
 spectively as 0, 1, 2, and 3). Strecker (Ann. Ch. Pharm. Ixviii. 47) showed that the 
 rule admitted of a somewhat more extended application in the form B = b + b' aq, 
 where aq denotes the number of atoms of water which separate in the reaction. P i r i a 
 (Ann. Ch. Pharm. xcvi. 381), observing that, when more than two substances reacted 
 upon each other, the number of atoms of water formed was usually one less than the 
 number of reacting substances, expressed the rule of basicity in the following form, 
 =. b + b' + b 1 ' + . . . . (n 1), (n being the number of reacting substances). 
 In all these expressions, one substance only is regarded as the essential product of the 
 reaction, but, if we take into consideration the basicity of all the products (water, 
 hydrochloric acid, &c. as well as more complex subatances) and regard water as a 
 monobasic* acid, we arrive at the following expression The sum of the basicities of 
 the products of a reaction is equal to the sum of the basicities of the reacting bodies. 
 
 Examples : 
 
 HC1 + KHO = KC1 + H 2 
 Basicities 1 + 0=0 +1 
 
 H 2 S0 4 + KHO = KHSO* + H 2 
 Basicities 2 + = 1 +1 
 
 H 2 S0 4 + KHO + KHO = K 2 S0 4 + H 2 + H 2 
 Basicities 2 + + = +1+1 
 
 Acetate of 
 Acetic acid. Alcohol. ethyl. 
 
 C 2 HK) 2 
 Basicities 1 + 
 
 C 2 H 4 2 + NH 8 
 Basicities 1 + 
 
 Acetochlor- 
 hydrobrom- 
 Glycerin. hydrin. 
 
 C 2 H 4 2 + HC1 + HBr + C 3 H 8 3 = C 5 H 8 2 ClBr + H 2 + H 2 + H 2 
 Basicities 1+1+1+0= +1 + 1+1 
 
 Fhosphamide. 
 
 PONH* + H 2 + H 2 + H 2 = H 3 PO + NH 3 + NH 3 + NH 3 
 
 Basicities +1 + 1 + 1=3+0+0+0 
 
 The application of the rule of basicity to substances which, like glycollic acid, are 
 monatomic in some relations but diatomic in others, or, like phenylic alcohol (carbolic 
 acid), are intermediate between neutral bodies and acids, often leads, as might be ex- 
 pected, to contradictory results. It must be looked upon, not as a law universally true, 
 but as a rule applicable to the majority of cases, and always dependent on our defini- 
 tions of acidity and basicity. (Comp. Kekul6, Ann. Ch. Pharm. cvi. 130.) 
 
 It has been pointed out by B eke toff" (Bullet, de 1' Academic de St. Petersbourg, xii. 
 369) that this law, in any of the forms yet given to it, gives contradictory results 
 when applied to the three following reactions, which nevertheless are strictly com- 
 parable with each other. 
 
 * If water be also considered as a monacid base,, the acidity of bases (or the number of atoms of acid 
 with which they react, a property correlative with bast, -fty,} [is usually conformable to the following 
 rule : The sum of the acidities of the products of a reaction ts equal to the sum of the acidities of the 
 reagents. The representation of water as a monobasic acid and as a monacid base expresses the fact 
 that it easily takes up 1 atom of an electro-positive, or of an electro-negative radicle in exchange for an 
 a'om of hydrogen, or, an electro-positive and an electro-negative radicle in exchange for the two atoms 
 of hydrogen. The representation of water as a dibasic acid (or as a diacid base) expresses the possi- 
 bility of replacing both atoms of hydrogen by the same radicle (formation of anhydrides). This re- 
 placement though not unfrequent, certainly takes place less readilv than the replacement of 1 atom of 
 hydrogen only, or than the replacement of the two by radicles of different electro-chemical qualities. 
 Either view, however, is evidently entirely relative. 
 VOL. I. E 
 
50 ACIDS. 
 
 Benzole 
 acid. Alcohol. 
 
 1.CTPO* + (SPO 
 Basicities 1 + 
 
 Benzoate 
 of ethyl. 
 
 = + 
 
 IPO 
 1 
 
 Benzoic 
 acid. 
 
 Acetic 
 acid. 
 
 Aceto- 
 benzoic 
 anhydride. 
 
 
 Basicities 1 
 
 + 1 
 
 = cSS? + 
 
 + 
 
 H 2 
 1 
 
 Alcohol 
 
 Methylic 
 alcohol. 
 
 Methyl- 
 ethyl 
 ether. 
 
 
 CH*0 = C 3 H 8 + H 2 
 Basicities 0+0 0+1 
 
 According to the conventions which have been made above, the sum of the basicities 
 of the products of the first reaction is equal to the sum of the basicities of the re- 
 agents, but in the second reaction it is less, and in the third it is greater. The 
 obviously artificial character of the law of basicity, which is sufficiently shown 
 by these instances, induced Beketoff to propose to compare the whole quantity of 
 replaceable hydrogen in the reagents with that in the products, instead of merely 
 comparing their basicities, or the number of atoms of hydrogen which are easily re- 
 placeable by basylous radicles. If the so-called typical formulae (see FORMULA, 
 RATIONAL) are employed in writing the above reactions, it at once becomes evident 
 that in each case the whole quantity of replaceable hydrogen is two atoms, both in the 
 products and in the reagents ; and in all regular double decompositions, the whole 
 number of atoms of replaceable hydrogen remains similarly unaltered (For an account 
 of all that is important in Beketoff' s paper, and for an extended criticism of the 
 law of basicity, see Kekule, Lehrbuch d. organisch. Chemie, pp. 210 219.) 
 
 A general classification of acids according to their composition cannot yet be given. 
 There are but few elements which are known to form more than two or three distinct 
 acids ; and, although many remarkable relations can be pointed out among the acids 
 formed by different elements, these relations are more important as indications of 
 analogies among the elements, than as serving for the classification of the acids them- 
 selves.* There is, however, one element carbon which, in combination with hy- 
 drogen and oxygen, forms a very large number of acids, the best known of which, 
 generally exhibit, when compared together, certain gradations of chemical composition 
 and properties, in accordance with which they can be arranged in a number of homo- 
 logous series. (See HOMOLOGY.) The most important of these series are the fol- 
 lowing : 
 
 a. Monobasic acids represented by the general formula OH 2n 2 . 
 
 Formic acid CH 2 2 , Caproic acid C 6 H 12 2 , 
 
 Acetic C 2 H 4 2 , (Enanthylic C'H0 2 , 
 Propionic C 3 H0 2 , Caprylic C 8 H 16 2 , 
 
 Butyric C 4 H 8 2 , Pelargonic C 9 H 18 2 , 
 Valeric C S H 10 2 , Rutic or capric C 10 H 20 2 , 
 
 &c. 
 
 The acids of this series are found in various vegetable and animal products ; several 
 of them occur in combination with glycerin as the chief constituents of most natural 
 solid and liquid fats. The first four have been found in mineral waters (Scheerer, 
 Ann. Ch. Pharm. xcix. 257). They are produced artificially by a great variety of 
 processes, the most important of which are the following : 
 1. The oxidation of the alcohols OH 2n + 2 
 
 C 2 H 6 + O 2 = C 2 H 4 2 + IPO. 
 
 Ethyl- Acetic 
 
 alcohol. acid. 
 
 2. The decomposition of the so-called nitriles, or cyanides of alcohol-radicles, of the 
 formula C n H 2n - 'N, by alkaline hydrates. 
 
 C 3 H 5 N + 2H 2 = C 3 H 6 2 + NH 8 . 
 
 Acetonitrile Propionic 
 
 or cyanide acid. 
 
 of ethyl. 
 
 * For an able exposition of nearly all that can yet be said on this point, see Od ling, Phil. Mng. xviii. 
 3f)8; also a lecture on " Acids and Salts," delivered by the same at the Royal Institution, 30th March. 
 1860, Chemical News, i. 220. 
 
ACIDS. 51 
 
 3. The combination of the potassium- and sodium- compounds of the alcohol-radiclea 
 OH 2n+1 with carbonic anydride. 
 
 C 2 H 5 Na + CO 2 = C 3 H 5 Na0 2 . 
 
 4. The oxidation, destructive distillation, fermentation, or putrefactive decompo- 
 sition of complex organic compounds. 
 
 When a fixed- alkaline, or alkaline-earthy salt of one of these acids is subjected to 
 dry distillation, a carbonate and an acetone are generally produced. These products 
 are formed by the decomposition of two atoms of the salt. 
 
 The dry distillation of a mixture of the fixed-alkaline, or alkaline- earthy, salts of 
 two acids of this series gives rise, in like manner, to a carbonate and to an acetone 
 intermediate in composition between the two acetones corresponding to the acids 
 employed. 
 
 When one of the salts is a formate, a similar reaction takes place, but an aldehyde 
 is then produced instead of an acetone. 
 
 In some cases the dry distillation of salts of these acids produces (besides acetones) 
 aldehydes, or isomeric compounds (butyral, valeral ) and hydrocarbons. (See ALDE- 
 HYDES, ACETONES.) 
 
 When distilled with excess of alkaline hydrate, they give hydrocarbons of the 
 formula OH n2+2 (hydrides of alcohol-radicles) and alkaline carbonate. 
 C 2 H 3 K0 2 + HKO = CK 2 3 + CH 4 . 
 
 Acet. potas- Hydride 
 
 sium. of methyl. 
 
 With pentachoride of phoshorus they produce chlorides of the formula C n H 2n ~ 1 OCl ; 
 C 2 H 4 2 + PC1 5 = C 2 H 3 OC1 + FOCI 3 + HC1 
 
 Acetic acid Chloride 
 
 ofacetyl. 
 
 Their alkaline salts distilled with arsenious anhydride give compounds of arsenic 
 with the alcohol-radicles. (See ARSENIC.) 
 
 Subjected to electrolysis, they give carbonates, alcohol-radicles, hydrogen and hy- 
 drocarbons of the form C D H 2n and OH 2 "- 1 " 2 . 
 
 Under the influence of chlorine (or bromine) they lose one or more atoms of hydro- 
 gen, and take up in exchange an equivalent quantity of chlorine, forming chloracids 
 whose general properties usually resemble closely those of the normal acids from which 
 they are formed. 
 
 C 2 H 4 2 + Cl 2 = C 2 H 3 C10 2 + HC1. 
 
 Acetic acid. 
 
 + Br 4 - C 2 H 2 Br 2 2 + 2HBr. 
 
 + Cl 6 = C'HCPO 2 + 3HC1. 
 
 b. Acids represented by the formula OH 2n O s , di-atomic, but usually monobasic. 
 The acids of this series differ from those of series a by containing three, instead of 
 two, atoms of oxygen. 
 
 Carbonic acid . . . . . . CH 2 3 , 
 
 Glycollic C 2 H 4 3 , 
 
 Lactic C S H 6 3 , 
 
 Butylactic , C 4 H 8 3 , 
 
 Valerolactic (Buttlerow) . . . . C 5 H 10 3 , 
 
 Leucic , C 6 H 12 3 . 
 
 These acids are formed 
 
 1. By the reaction of the protochloro- or protobromo- derivatives of the acids of 
 series a with hydrates. 
 
 C 8 H 3 C10 2 + HKO = C 2 H 4 3 + KC1. 
 
 Chloracetic Glycollic 
 
 acid. acid. 
 
 E 2 
 
52 ACIDS. 
 
 2. By the oxidation of the diatomic alcohols, C n H 2n + 2 2 (glycols). 
 C 2 H 6 2 + O 2 = C 2 H 4 3 + H'O. 
 
 3. By the oxidation of certain amides of animal origin (glycocol and homologues), 
 especially by nitrous acid. 
 
 (OTNO 2 + NHO 2 = C 2 H 4 3 + N 2 + H 2 0. 
 
 Glycocol. Glycollic 
 
 acid. 
 
 4. By fermentation. 
 
 The acids of this series are decomposed by heat into anhydrides and water. (In 
 the case of carbonic acid, this decomposition takes place at the ordinary temperature.) 
 
 With pentachloride of phosphorus, they produce diatomic chlorides of the formula 
 C"H 2 - 2 OC1 2 ; e.g. 
 
 C 3 H 6 3 + 2PC1 5 = C 3 H 4 OC1 2 + 2POCP + 2HC1 
 
 Lactic acid. Chloride of 
 
 lactyl. 
 
 Lactic acid heated with hydriodic acid produces water, iodine and propionic acid 
 (Lautemann) : 
 
 CWO 3 + 2HI = C 3 H 6 2 + H 2 + I 2 
 
 Lactic acid. Propionic acid. 
 
 This will probably be found to be a general method of converting acids of series 
 b into the corresponding acids of series a. 
 
 c. Dibasic acids represented by the formula C"H (2ll ~ 2) 4 . The acids of this series 
 represent the acids of series b, in which 2 at. hydrogen are replaced by an equivalent 
 of oxygen. 
 
 Oxalic acid . . . C 2 H 2 4 
 
 Malonic . C 3 H 4 4 
 
 Succinic . C 4 H 6 0* 
 
 Lipic . C 5 H 8 4 
 
 Pimelic acid . . . C'H 12 4 
 Suberic C 8 H 14 4 
 
 Anchoic . C 9 H 16 4 
 
 Sebacic ,. , C IO H 18 4 . 
 
 Adipic . C 6 H 10 4 
 
 These acids are, for the most part, products of oxidation. They are solid at ordinary 
 temperatures, and are not volatile without partial or complete decomposition. Some 
 of them are decomposed by heat into carbonic anhydride and a monobasic acid of 
 series a. 
 
 C S H 4 4 = C 2 H 4 2 + CO 2 . 
 
 Malonic acid. Acetic acid. 
 
 Several of them also produce acids of series a, when fused with excess of alkaline 
 hydrate; the reaction is accompanied by evolution of hydrogen (Gerhard t). 
 Suberic and sebacic acids heated with a great excess of baryta, lose the elements of 
 of 2 at. carbonic anydride and yield the hydrocarbons C 6 H 14 and C 8 H 18 ; it is pro- 
 bable that other acids of this series would be decomposed in like manner if similarly 
 treated. (Riche.) 
 
 Pentachloride of phosphorus reacts on the acids of this series, producing at first 
 the corresponding anhydrides, which are afterwards converted by excess of the 
 chloride into chlorides of the formula OH> 4 2 C1 2 ; e. g. 
 
 1. C 4 H 6 4 + PCI 5 = C 4 H 4 3 + 2HC1 + POC1 3 . 
 
 Succinic Succinic 
 
 acid. anhydride. 
 
 2. C'H 4 3 - PCI 5 = C 4 H 4 2 C1 2 + POC1 3 
 
 Succinic Chloride of 
 
 anhydride. succinyl. 
 
 There is a certain number of acids which do not enter into any of these three series, 
 but which are related to certain members of them in the same way that the acids be- 
 longing to the different series are related to each other. For instance, glyoxylic acid, 
 C 2 H 4 4 , differs from glycollic acid, C*H 4 3 , in the same way that the latter differs 
 from acetic acid, C 2 H 4 2 ; namely, by containing one more atom of oxygen. And 
 just as bromacetic acid when boiled with oxide of silver produces bromide of silver and 
 glycollic acid 
 
 C 2 H 3 Br0 2 + HAgO = C^BX) 3 + AgBr 
 
 Bromacetic Glycollic 
 
 acid. acid. 
 
ACIDS. 
 
 53 
 
 bromoglycollic acid, when similarly treated, yields bromide of silver and glyoxylic 
 acid (Perkin and Duppa), 
 
 C 2 H 3 Br0 8 + HAgO = C 2 H 4 0* + AgBr. 
 
 differ from succinic acid by containing respectively one and two atoms more oxygen 
 and they can be converted into succinic acid by heating them with hydriodic acid, in 
 the same way that lactic acid can be converted into propionic acid (Schmidt); moreover, 
 dibromosuccinic acid is decomposed, when boiled with oxide of silver, into bromide 
 of silver and tartaric acid, just as dibromacetic acid is decomposed under similar 
 circumstances into bromide of silver and glyoxylic acid (Perkin and Duppa). The 
 same relation that exists between malic and succinic acids exists also between their 
 homologues, tartronic and malonic acids C 3 H 4 5 and C 3 H 4 4 , but in the case of 
 these acids, the conversion of one into the other has not yet been effected. There is 
 little doubt that these acids glyoxylic and glyceric, tartronic and malic, and tartaric 
 represent homologous series running parallel with the three first described, but of 
 which the other terms are as yet unknown. 
 
 The relation of all the series of acids, of which we have yet spoken, to each other 
 and to the alcohols homologous with common alcohol, glycol, and glycerine, is shown 
 in the following Table, giving the general formulae of each series. It will be seen 
 that of the formulae written one above another, each contains one atom of oxygen 
 more than the formula next above it, and that of the formulae written in the same 
 horizontal line, each contains two atoms of hydrogen less, and one atom of oxygen 
 more, than the one directly to the left of it. Where known, a special illustration of 
 each general formula is given. 
 
 Monatomic. 
 
 ALCOHOLS. 
 
 ACIDS. 
 
 CH?n+20 
 Propylic, CPH S O. 
 
 Monobasic. 
 
 CnH2n()2 
 
 Propionic, C3H6Q2 
 and acids of series a. 
 
 OH2n 2Q3 
 
 Pyruvic, C 3 H 4 O 3 ? 
 
 CnH2n 4Q* 
 
 Diatomic. 
 
 C n H2 n -M02 
 
 Propylic glycol, 
 (j3Hoi 
 
 CH2n03 
 
 Lactic, C3H6Q 3 
 and acids of series b. 
 
 Dibasic. 
 
 CnH2n-2O 
 
 M;ilonic, C3H0* 
 Succinic, C 4 R6Q4 
 and acids of series c. 
 
 CnH2n-40^ 
 Mesoxalic, C 3 H2O 
 
 Triatomic. 
 
 CnH2n+2Q3 
 Glycerin, C3H8Q3 
 
 CnH2n{)4 
 Glyceric, C3H6Q* 
 
 CuH2n-2Q5 
 
 Tartronic, C 3 H4O 5 
 Malic, C 4 H 6 Qi 
 
 Tribasic. 
 
 CnH2n-60< 
 
 Tetratomic. 
 
 C n H2n+2O' 
 
 CoH2n+Q 5 
 
 OH2n 2Q6 
 Tartaric, C4H6Q& 
 
 CnH2n-4Q7 
 Citric, Cfill*O7 
 
 Another series of acids is represented by the general formula OH 2 " 2 2 . They 
 are monobasic like the acids of series a, but differ from these by containing 2 atoms 
 less hydrogen combined with the same quantity of carbon and oxygen. None of 
 them have yet been very thoroughly investigated, and the empirical composition even 
 of some of them is still open to discussion. The terms of this series hitherto more or 
 less known are 
 
 Acrylic acid . . C 3 H 4 2 Campholic acid . . C 10 H 18 2 
 
 Crotonic . . C 4 H 8 2 Moringic . . C 15 H 28 2 
 
 Angelic . . C 5 H 8 2 Hypogaeic . . C^H^O 2 
 
 Pyroterebic . . C 6 H'0 2 Oleic . . C 18 H 34 2 
 
 Damaluric . . C 7 H I2 O- Brassic . . C 22 H 42 
 
 E 3 
 
54 ACONITIC ACID. 
 
 The following dibasic acids represented by the general formula OH 2n - 4 4 , are 
 related so far at least as composition is concerned to the last series, in the same 
 manner as the acids of series c are related to those of series a. 
 
 Fumaric acid . . C 4 H 4 4 
 Citraconic ) 
 
 Itaconic > acids . . C 5 H 6 4 
 Mesaconic ) 
 
 Terebic. . . . C 7 H 10 4 
 Camphoric . . . C IO H 16 0* 
 
 There are still two other series of acids, presenting the same mutual relations as 
 the series a and b, several terms of which have been very fully studied. They are, 
 
 1. Monobasic acids of the general formula OH 2 " *0 2 . " 
 
 Benzoic acid ....... C 7 H 6 2 
 
 Toluylic ....... C 8 H fl 2 
 
 Cuminic ....... C'H I2 2 
 
 2. Diatomic acids of the general formula OH 2n - 8 3 . 
 
 Oxybenzoic acid ...... C 7 H B 3 
 
 Oxytoluylic ...... C 8 H 8 3 
 
 Phloretic ...... C 9 H 10 3 
 
 Oxycuminic ...... C 10 H 12 3 
 
 The position which a few of the yet remaining organic acids occupy in relation 
 to the series already recognised can be indicated with tolerable certainty ; but the 
 greater number are still so imperfectly known that they cannot be included in any 
 classification which is not entirely articifial and empirical. CK C. F. 
 
 ACOWITIC ACI3>. C (i II 6 6 = g3 O 3 [or <7 12 # 6 <9 12 ]. Equisetic acid, 
 
 Citridic Acid. (G-m. xii. 408; Gerh. ii. 110; iii. 960; iv. 922.) An acid found 
 in the roots and leaves of monkshood (Aconitum Napellus) and other aconites, and in 
 the herb of Delphinium Consolida, collected after flowering. It is also produced by the 
 metamorphosis of citric acid under the influence of heat. It exists in the aconite as 
 aconitate of calcium, which crystallises out on evaporating the juice, and on account 
 of its insolubility may by freed from the colouring matters and other impurities, by 
 washing with water and alcohol. The aconitate of calcium is then dissolved in very dilute 
 nitric acid, and the filtered liquid is precipitated with acetate of lead. The aconitate 
 of lead, after being well washed, is decomposed by hydrosulphuric acid, the sulphide 
 of lead filtered off, and the solution which contains the aconitic acid is evaporated to 
 dryness, and the residue treated with ether, in which the acid dissolves, leaving the 
 impurities. 
 
 To obtain it from citric acid, the acid is heated till it ceases to give off inflammable 
 vapours ; and the residue dissolved in alcohol is treated with hydrochloric acid, by which 
 aconitic ether is formed, and separates on addition of water, as an oily liquid, which 
 by treatment with potash is converted into aconitate of potassium. This salt is 
 next converted into a lead salt, and the acid is liberated by hydrosulphuric acid as in 
 the preceding process. 
 
 On evaporating the ethereal solution, it is left as an amorphous mass, very soluble 
 in water, alcohol, and ether. When heated to 160 it is converted into an oily liquid, 
 which is itaconic acid, C 6 H 6 6 = C 5 H 6 4 + CO 2 . It is distinguished from fumaric 
 acid by being more soluble in water, and from maleic acid by not crystallising. 
 
 Aconitic acid is tribasic, and forms three classes of salts, viz. C 6 H 3 M 3 6 ; C 6 H 3 (M 2 H)0 6 ; 
 and C 6 H 3 (MH 2 )0 6 . The aconitates of ammonium, potassium, sodium, magnesium Hnd 
 zinc, dissolve readily in water ; the rest are insoluble or sparingly soluble. The soluble 
 aconitates form with solutions of lead and silver, white flocculent precipitates, which do 
 not become crystalline either by ebullition or after prolonged immersion in the liquid, 
 whereas the lead and silver precipitates formed by fumaric and maleic acid are 
 crystalline. 
 
 "With ammonium and potassium, aconitic acid forms salts, corresponding to each of 
 the three formulae above given ; with sodium, a disodic and a trisodic salt. Aconitate 
 of calcium, C 6 H 3 Ca 3 6 + 3H-0 ? occurs in large quantity in extract of aconite. It may 
 also be prepared by dissolving lime in aconitic acid, or by precipitating chloride of 
 calcium with aconitate of sodium. It dissolves in 99 parts of cold water, more readily 
 in boiling water. The solution evaporated at a gentle heat, and without agitation, 
 yields a gelatinous mass which dries up to a gum ; but if a few crystals of the salt be 
 introduced into the solution, the whole is deposited in delicate crystals. Aconitate of 
 manganese, C 6 H 3 Mn 3 O 6 + 6H 2 0, is obtained by boiling the acid with carbonate of 
 manganese. Small rose-coloured octahedrons, sparingly soluble in cold water. Aconi- 
 tate of lead, 2C 6 H 3 Pb 3 6 + 3H-0, is sparingly soluble in boiling water, and gives off 
 5'29 per cent, water at 140, Aconitate of silver, C 6 H 3 Ag 8 8 . Nitrate of silver is not 
 
ACON1TINE. 55 
 
 precipitated by the free acid, but with the alkaline aconitates it forms a white, 
 amorphous, sparingly soluble precipitate, which is partly reduced to the metallic state 
 by boiling with water. 
 
 Aconitate of Ethyl, C 6 H S (C 2 H 5 ) 3 6 , is prepared by dissolving aconitic acid in five 
 times its weight of absolute alcohol, and saturating the solution with hydrochloric 
 acid. On addition of water, the ether separates in the form of an oily layer. 
 
 It is a colourless liquid, having an aromatic odour, and very bitter taste. Boils at 
 236, and has a density of 1'074, at 14. 
 
 Aconitanilic acid or Phenyl-aconitamic acid. C 12 H 9 N0 4 = 
 
 an amic acid formed on the type ] TT , three of the hydrogen-atoms in the am- 
 monium being replaced by the triatomic radicle, aconityl, and the fourth by phenyl. 
 It is obtained by the action of water on the (not yet isolated) compound, C 12 H 8 N0 3 C1, 
 produced by treating citranilic (phenyl-citramic) acid with perchloride of phosphorus ; 
 probably thus : 
 
 C 12 HN0 5 + 2PC1 5 = C 12 H 8 N0 3 C1 + 2POC1 3 + 3HC1; 
 
 Citranilic acid. 
 
 and C 12 HN0 3 C1 + H 2 = C 12 H 9 N0 4 + HC1. 
 
 When 1 at. citranilic acid is mixed with 2 at. perchloride of phosphorus, added 
 by small portions, and the action is assisted at intervals by a gentle heat, the whole 
 dissolves, forming a yellow liquid; and on treating this liquid with water, hydro- 
 chloric acid is evolved, and aconitanilic acid separates in the form of a soft substance, 
 which, by solution in hot water and cooling, may be obtained in small yellow needles, 
 but cannot be rendered colourless even by repeated crystallisation. The acid dissolves 
 sparingly in water, easily in alcohol, and very easily in aqueous ammonia ; and the 
 ammoniacal solution mixed with nitrate of silver, yields rose-coloured flakes of the 
 silver-salt, C'-HMgNO 4 . (Pebal, Ann. Ch. Pharm. xcviii. 83.) 
 
 Aconitodianil or Diphenyl-aconito-diawAde, C 18 H 14 N 2 3 = N 2 .(C fl H 3 3 .)" / (C (5 H 5 ) 2 .H, 
 is produced (together with aconitanilide), by the action of aconitic acid upon aniline : 
 
 C 6 H 6 6 + 2C 6 H 7 N = C 18 H I4 N 2 3 + 3H 2 0. 
 also by the action of oxychlorocitric acid upon aniline : 
 
 C fi H 8 6 Cl 2 + 2C 6 H 7 N = C 18 H 14 N 2 3 + 3H 2 + 2HC1. 
 
 It is insoluble in water, very sparingly soluble in cold alcohol. From solution in a 
 large quantity of boiling alcohol, it crystallises on cooling in slender, pale yellow needles. 
 (Pebal.) 
 
 Aconitanilide or Tripkenyl-aconito-triamide, C 24 H 21 N 3 3 = N 3 (C 6 H 3 8 )" / (C 6 H 5 ) 3 .H 3 , 
 appears to be formed simultaneously with aconitodianil, by the action of aconitic acid 
 or oxychlorocitric acid on aniline : 
 
 C 6 H 6 6 + 3C 6 H 7 N = C 24 H 21 N 3 3 + 3H 2 
 and C 6 H 8 G C1 2 + 3C 6 H 7 N = C 24 H 21 N 3 3 + 3H 2 + 2HC1. 
 
 It is an amorphous substance, insoluble in water, but very soluble in cold alcohol, and 
 is thereby easily separated from aconito-dianil. (Pebal.) 
 The amides of aconitic acid have not yet been obtained. 
 
 ACOTTITIlffE. (7H 47 NO 7 [or C' 6e # 47 A 7 O n ]. (Geiger, Ann. Ch. Pharm. vii. 269 ; 
 Morson, Pogg. xlii. 175; v. Planta, Ann. Ch. Pharm. Ixxiv. 245.) The alkaloid 
 contained in the Aconitum Napellus, and probably in all the acrid aconites. It is 
 obtained by exhausting the leaves with alcohol, saturating the extract with milk 
 of lime, separating the lime by sulphuric acid, evaporating the filtered solution of 
 sulphate of acontine at a gentle heat to expel the alcohol, then diluting with water, 
 and treating the solution with carbonate of potassium, which precipitates impure 
 aconitine. The product is purified by redissolving it in alcohol, treating the solution 
 with animal charcoal, reconverting the base into sulphate, again decomposing this 
 salt with hydrate of lime, and treating the precipitate with ether, which dissolves 
 nothing but the aconitine. 
 
 Pure aconitine is deposited from solution in dilute alcohol in white pulverulent 
 grains, or sometimes in a compact, vitreous, transparent mass. It is inodorous, but has a 
 persistent, bitter, and acrid taste. It dissolves sparingly in cold water, and in 50 
 parts of boiling water, forming a strongly alkaline solution. It is very soluble in 
 alcohol, less in ether. At 80 it melts into a vitreous mass, without loss of weight ; 
 at 120 it turns brown, and at a higher temperature suffers complete decomposition. 
 It is dissolved without colour by nitric acid. Sulphuric acid colours it first yellow, 
 
 E 4 
 
56 ACONITYL ACROLEIN. 
 
 then violet ; tincture of iodine forms with it a kermes-coloured precipitate. It is in- 
 tensely poisonous, 5^ of a grain sufficing to kill a sparrow in a few minutes, and ^ of 
 a grain killing it instantly. 
 
 The salts of aconitine do not crystallise readily. They are not deliquescent, but 
 dissolve easily in water and alcohol. The solutions yield a precipitate of aconitine 
 with alkalies. The hydrochlorate, C 30 H 47 N0 7 .2HC1, is obtained by passing dry hydro- 
 chloric acid gas over dry aconitine. Its solution is not precipitated by chloride of 
 platinum, but yields a white precipitate with chloride of mercury, yellow with chloride 
 of gold, and also with picric acid. 
 
 ACQWITYIi. C 6 H 3 3 ; the triatomic radicle of aconitic acid and its derivatives. 
 
 ACRENE. A name given by Laurent to the hydrocarbon, C 3 H 4 . (See ALLYLENE.) 
 
 jA.CROX.EZXT. C S H 4 [or CWO 2 ]. (Eedtenbacher, Ann. Ch. Pharm. xlvii. 
 114; Geuther and Cartmell, ibid. cxii. 1 ; Hiibner and Geuther, ibid. cxiv. 35; 
 Gm. ix. 365; xii. 550; Gerh. i. iv. 779, 914.) This body constitutes the acrid prin- 
 ciple produced by the destructive distillation of fatty bodies, resulting in fact from the 
 decomposition of glycerin. It is also produced by the action of platinum-black or of 
 a mixture of acid chromate of potassium and sulphuric acid on allyl-alcohol, being indeed 
 the aldehyde of the allyl series. (Cahours and Hofmann.) (See AIXYL.) 
 
 Acrolein is best prepared by distilling in a capacious retort a mixture of glycerin 
 and acid sulphate of potassium, or phosphoric anhydride. When phosphoric anhydride 
 is used, the distillate consists entirely of acrolein ; but the contents of the retort 
 are very apt to froth over. With acid sulphate of potassium, the distillation is easier, 
 but the acrolein is contaminated with acrylic acid, sulphurous acid, and other pro- 
 ducts. The distillate is collected in a receiver kept very cold, and provided with 
 a long discharge-tube passing into the chimney in order to carry off the vapours, 
 which are intensely irritating to the eyes. To purify the acrolein, it is digested with 
 oxide of lead, which removes the acid impurities, then rectified in the water-bath, 
 dehydrated over chloride of calcum, and again rectified. As acrolein oxidises very 
 rapidly by contact with the air, all these operations must be conducted with a stream 
 of dry carbonic acid gas passing through the apparatus. (Redtenbacher.) 
 
 Hiibner and Geuther distil 1 pt. of glycerin with 2 pts. of acid sulphate of potassium, 
 over an open flame, the bottom of the flask being protected by wire-gauze, and a 
 quantity of oxide of lead being placed in the receiver to neutralise the acid products. 
 According to these chemists, the process consists of two stages, the acid sulphate of . 
 potassium first dissolving in the glycerin, forming glycerosulphate of potassium, with 
 elimination of water, so that the first portion of the distillate consists chiefly of water, 
 with but little acrolein ; but, afterwards, when the liquid becomes more concentrated, 
 the glycerosulphate is decomposed, and acrolein passes over with only a small quantity 
 of water. This latter portion of the distillate is subsequently purified as in Redten- 
 bacher's process. 
 
 Acrolein is a colourless, limpid, strongly refracting liquid, lighter than water, and 
 boiling at 52^4 (Hiibner and Geuther). Vapour-density 1 '897. Its vapour is so 
 intensely irritating, that a few drops diffused through a room are sufficient to render 
 the atmosphere insupportable. It burns readily with a clear bright flame. It dissolves 
 in about 40 parts of water, and very readily in ether. The solutions are neutral at 
 first, but gradually turn acid by contact with the air. 
 
 Acrolein cannot be preserved long, even in closed vessels, as it changes spon- 
 taneously into a flocculent substance called by Redtenbacher disacryl, and more rarely 
 into a resinous substance, disacryl-rcsin. It sometimes solidifies immediately after 
 being prepared, even in sealed tubes. It undergoes the same transformation under 
 water, which at the same time becomes charged with acrylic, formic and acetic acids. 
 Vapour of acrolein passed through a red-hot tube is decomposed, with formation of 
 water and deposition of charcoal. 
 
 Caustic alkalis convert acrolein into resinous products. By oxidising agents it is 
 converted into acrylic acid. It reduces oxide of silver with considerable evolution 
 of heat, forming acrylate of silver, which remains dissolved. Nitrate of silver forms 
 with aqueous acroleiu a white curdy precipitate (probably C^H^AgO) which, however, 
 gradually decomposes, yielding metallic silver and acrylate of silver. On adding a 
 few drops of ammonia, and boiling the liquid, the silver is immediately reduced, but 
 not in the specular form as with aldehyde. Nitric acid attacks acrolein strongly, 
 converting it into acrylic acid. Strong sulphuric acid blackens it, giving off sulphurous 
 anhydride at the same time. With chlorine and bromine, it forms heavy oils, to- 
 gether with hydrochloric or hydrobromic acid. Perchloride of j)~hos]jh(jrus acts 
 violently on acrolein, forming dichloride of allylene C 3 H 4 .C1 2 (see ALI,YI-ENE), and 
 another oily liquid which appears to be isomeric- with it. With acetic anhydride, it 
 unites directly, forming the compound C 3 H'O.C 4 H G 3 , which is identical in every 
 
ACRYLIC ACID. 57 
 
 respect with the compound resulting from the action of acetate of silver on dichloride 
 of allylene (Hiibner and G-euther), and may therefore be regarded as diacetate of 
 aUylene (C 3 H 4 )".(C 2 H 3 0) 2 .0. 
 
 Acrolein-ammonia. C 12 H 20 N 2 8 = C 12 H I8 N 2 2 .H 2 0. Acrolein acts strongly on 
 ammonia, forming a solid compound (first obtained by Eedtenbacher) : 
 
 4C 3 H 4 + 2NH 3 = C 12 H-N 2 3 + H 2 0. 
 
 It is best prepared by gradually adding a saturated solution of ammonia-gas in alcohol 
 to an alcoholic or ethereal solution of acrolein, and precipitating by addition of ether. 
 It is a white or yellowish, amorphous, odourless compound which turns brown at a 
 gentle heat and begins to decompose at 100, giving off volatile basic products. In 
 the moist state it dissolves readily in cold water and warm alcohol ; less in hot water. 
 It dissolves readily in acids, and is precipitated therefrom by alkalis and alkaline 
 carbonates. Hence it appears to be a base. Its solution in hydrochloric acid forms 
 with dichloride of platinum, a light yellow precipitate containing, when dried at 100, 
 C'2H 20 N 2 2 . 2HC1. 2PtCl*, or C 6 H 10 NO.HCl.PtCl 2 . (Hiibner and G-euther.) 
 
 Acrolein with Acid Sulphite of Sodium. When acrolein is poured into in aqueous so- 
 lution of acid sulphite of sodium, its odour is destroyed, and by evaporation over the 
 water-bath, a brown deliquescent syrup is obtained which does not deposit crystals, 
 and from which neither acrolein can be separated by boiling with carbonate of sodium, 
 nor sulphurous acid by boiling with sulphuric acid. (Hiibner and G-euther.) 
 
 Hydrochlorate of Acrolein, C 3 H 4 O.HC1. Produced by passing dry hydrochloric 
 acid gas into anhydrous acrolein in a vessel surrounded by cold water. The viscid 
 product, washed and dried over oil of vitriol in vacuo, yields hydrochlorate of acrolein 
 as a mass of velvety crystals, which melt at 32 into a thick oil, having the odour 
 of rancid fat. It is insoluble in water, but readily soluble in alcohol and ether, on 
 the evaporation of which it remains as a thick oil. It is resolved by heat into 
 acrolein and hydrochloric acid. It is not apparently altered by boiling with water, 
 or by the action of dilute solutions of the alkalis. Heated with ammonia to 100 in a 
 sealed tube, it yields chloride of ammonium and acrolein-ammonia. Strong hydro- 
 chloric acid decomposes it, setting the acrolein free ; a similar action is exerted by 
 dilute sulphuric or nitric acid. Hydrochlorate of acrolein in alcoholic solution does 
 not combine with dichloride of platinum, and very slowly reduces a boiling ammo- 
 niacal solution of nitrate of silver. 
 
 Gaseous hydriodic acid passed into acrolein exerts a violent action, attended with a 
 hissing noise like that of red-hot iron plunged into water. The product is a resinous 
 body which is insoluble in alcohol, ether, acids and alkalis, gives off iodine when 
 heated, and yields a small quantity of free iodine to bisulphide of carbon. 
 
 METACROLEIN. Hydrochlorate of acrolein heated with hydrate of potassium gives 
 off hydrogen, and yields an oily distillate, which solidifies in magnificent colourless, 
 needle-shaped crystals, consisting of metacrolein, a compound isomeric or more pro- 
 bably polymeric with acrolein. It is lighter than water, has an aromatic odour, and 
 a cooling taste with burning after- taste. It melts at 50, solidifies at about 45, or 
 volatilises a little before melting, so that it may be distilled with vapour of water. 
 By heat, it is changed into common acrolein. It is not affected by dilute alkalis, 
 but when heated with mineral acids it is changed more or less into acrolein. In 
 a stream of dry hydrochloric acid gas, it melts and is converted into the hydrochlorate 
 of acrolein above described. Hence it is probable that the compound so named is 
 really a hydrochlorate of metacrolein, perhaps C 6 H 8 2 .2HC1. 
 
 Hydriodate of Metacrolein is produced by passing dry hydriodic acid gas over meta- 
 crolein, as a heavy yellow liquid which resembles the hydrochlorate in taste and 
 appearance, and after washing in water, shows a tendency to crystallise at ordinary 
 temperatures. When placed over oil of vitriol, it decomposes, turning brown and 
 giving off iodine. 
 
 Hydriodic acid gas acts violently upon acrolein, producing a resinous substance 
 which is insoluble in alcohol, ether, acids and alkalis, and gives up iodine when 
 heated or when digested with bisulphide of carbon. (Geuther and Cartmell.) 
 
 ACRTZXXC ACID. C 3 H 4 2 = C 3 H 3 O.HO (or <7 6 // 4 4 ). (Gm. ix. 369; Gerh. 
 783 ; iv. 914.) Acroltic acid. This acid, discovered by Redtenbacher, is produced by 
 the oxidation of acrolein. The best agent to employ is oxide of silver, which, when di- 
 gested with acrolein, yields a deposit of metallic silver, and a solution of acrylate of 
 silver. This salt is decomposed by hydrosulphuric acid, and the acrylic acid thus set 
 free is purified by rectification. It is necessary carefully to cool the vessel during the 
 decomposition of the silver salt; otherwise, the heat developed is so great that an 
 explosion results. The acid is likewise obtained by the action of chromic acid on 
 oxide of allyl. (Hofmann and Cahou> s.) (See ALL YL.) 
 
58 ADIPIC ACID. 
 
 When purified, it is a colourless liquid, of an agreeable, slightly empyreumatic 
 odour. It is miscible with water in all proportions, and its boiling-point is inter- 
 mediate between that of formic and acetic acids. 
 
 It is a monobasic acid, its salts having the formula, C 8 (H 3 M)0 2 . They closely 
 resemble the formates and acetates, and are generally very soluble in water. 
 
 Acrylate of Sodium. 2C 3 (H 3 Na)0 2 + 5H 2 0, is obtained by saturating the acid with 
 carbonate of sodium and evaporating. It crystallises in transparent prisms. 
 
 Acrylate of Barium. C 3 (H 3 Ba)0 2 , is also a soluble salt. 
 
 Acrylate of Silver, C 3 (H 3 Ag)0 2 , forms white needles, having a silky lustre, and 
 very soluble in water. 
 
 Acrylate of Ethyl is obtained, though not in the pure state, by distilling acrylic 
 acid, or its sodium or barium-salt with alcohol and sulphuric acid. (Hedtenbacher.) 
 
 ACTXXTOXiXTE. A variety of Hornblende (q. v.) 
 
 ADAMANT. See DIAMOND. ADAM ATJTI3ME SPAR. See CORUNDUM. 
 
 ADAPTER or ADOPTER. A piece of tube of more or less conical form, used 
 to elongate the neck of a retort, and to connect it with a receiver. 
 
 ADHESXOXT. (See COHESION.) 
 
 ADHESIVE SI. ATE. (See SLATE.) 
 
 ADIAPHAXJOUS SPAR. (See GEHXENITE and SAUSSUEITE.) 
 
 ADXI^QXiE. A compact impure felspar, better known as petrosilex. It differs 
 from jaspar, which it otherwise much resembles, in being fusible before the blowpipe. 
 
 ADIPXC ACZD. C 6 H 10 4 = O 2 | C jp 8 , 2 [or 12 # 10 8 = C }2 H0 6 .2HO]. Adibasic 
 
 acid forming the fifth term of the series C 2 H 2n - 2 4 the lowest term of which is oxalic acid, 
 C 2 H 2 4 , and the highest at present known, sebacic acid, C 10 H 18 4 . It is produced by 
 the action of nitric acid on oleic acid, suet, spermaceti, and other fatty bodies. To pre- 
 pare it, tallow or suet is boiled in a capacious retort with nitric acid of ordinary strength, 
 which must be frequently renewed, and the distillate poured back till the fatty matter 
 disappears and crystals separate on cooling. The Liquid is then evaporated over the 
 water-bath till it solidifies in a crystalline mass on cooling ; this mass is washed in a 
 funnel, first with strong nitric acid, then with dilute nitric acid, and lastly with cold 
 water ; and the acid is finally purified by crystallisation from boiling water (M a 1 a g u t i). 
 Other acids of the same series are doubtless formed at the same time ; but according 
 to Malaguti, the crystals obtained in the manner just described have all the same 
 appearance, excepting the very last. Wirz (Ann. Ch. Pharm. civ. 257) obtains this 
 acid, together with several other members of the series, by the continued action of nitric 
 acid on the solid fatty acids of cocoa-nut oil. The action is continued for several 
 weeks till the mass solidifies to a crystalline magma. This product is resolved by 
 water into a mixture of several acids of the above series, and a heavy oil ; and the 
 acids are separated one from the other by fractional crystallisation from water and 
 alcohol, and lastly by fractional crystallisation of the silver-salts. (See ANCHOIC Aero. ) 
 The acid separates from its aqueous solution in crystalline crusts composed of soft, 
 white, opaque, hemispherical nodules, which appear to be aggregations of smaller crystals. 
 According to Wirz, these crystals dried at 100 contain water of crystallisation, their 
 formula being 2C 6 H 10 4 + H 2 [anal. 46-2, 46'4 and 47 '8 p. c. carbon, 6 '6 and 6*8 
 
 Lc. hydrogen; calc. 46*4 C and 7'0 H]. At 140 they melt and give off water, 
 ving the anhydrous acid C 6 H I0 4 [analysis, 48-2, and 48'3 C; 6'8 and 6'9 H; 
 calc. 49. 3 C and 6 -8 II] ; which soon afterwards sublimes in long slender needles [the 
 sublimed acid gave by analysis 49 '5 C and 6 '6 H]. 
 
 100 parts of water at 18 dissolve 7'73 of the crystallised acid : a hot solution 
 which deposited crystals abundantly on cooling, still retained 8-61 pts. of the acid in 
 100 pts. at 18 (Wirz). The acid dissolves very readily in hot alcohol and ether. 
 
 The adipates, C fl H*M 2 4 , are for the most part soluble in water and crystallisable ; 
 insoluble in alcohol. The ammonium-salt crystallises in needles (Laurent, Bromeis). 
 The barium-salt dried over sulphuric acid, forms opaque warty masses not containing 
 water of crystallisation (Wirz). The strontium-salt forms microscopic needles con- 
 taining 2C 6 H s Sr 2 4 + 3H 2 (Laurent). The calcium-salt resembles the barium-salt 
 in appearance, but contains 1 atom of water [C 6 H 8 Ca0 4 + H 2 0] which is given off 
 between 100 and 200 (Wirz). The silver-salt, C 6 H 8 Ag 2 4 , obtained by precipitating 
 the ammonium-salt with a considerable quantity of nitrate of silver, is a white 
 powder. 
 
 Adipate of Ethi/l, C 6 H 8 4 (C 2 H 5 ) 2 , obtained by saturating the alcoholic solution of 
 the acid with hydrochloric acid gas, is a yellowish oil of sp. gr. 1-001 at 20'5 which 
 lx)ils, with decomposition, at 230. It has a strong odour of apples and a bitter 
 
ADIPOCERE AESCULIC ACID. 59 
 
 caustic taste. Chlorine decomposes it, giving off hydrochloric acid and forming a 
 viscous mass. (Malaguti.) 
 
 ADXPOCERE. (From adcps, fat; and cera, wax.) A peculiar white substance, pro- 
 duced by the decomposition of animal matters under the influence of moisture and in 
 situations from which the air is excluded. It was first found by Fourcroy in the Cimetiere 
 d$s Innocents at Paris. A number of coffins had been piled one upon another, and 
 remained interred for about 20 years. The bodies were found compressed, as it were, 
 at the bottom of the coffins, and converted into a soft white substance resembling 
 cheese, which bore the imprints of the linen in which they had been wrapped. This 
 matter enclosed the bones, which were broken on the slightest pressure. It was 
 found to consist chiefly of margarate of ammonium together with the margarates of 
 potassium and calcium. 
 
 ADUXiARXA. (See FELSPAR.) 
 AEX>m,FORSXTE. (See EDELFOKSITE.) 
 
 AEG-XRXHT or AEGYRXW. (Handwork d. Chem. i. 169.) A mineral of the 
 augite family, occurring in the neighbourhood of Brevig in Norway, sometimes in very 
 la.rge and well-defined crystals belonging to the monoclinic system, and having the 
 general character and cleavage of augite. Colour greenish-black to leek-green. Lustre 
 vitreous. The edges exhibit various degrees of translucence, down to complete 
 opacity. Sp. gr. 3-43 to 3'50. Harduess about that of orthoclase. The mineral con- 
 tains a considerable quantity of iron, partly in the state of protoxide, partly of sesqui- 
 oxide, besides alumina, lime, magnesia, and soda, sometimes also protoxide of man- 
 ganese and potash, associated with silica, and sometimes with titanic acid. The 
 formula is not perfectly established, but it is probably of the general form, 
 3(M 2 O.Si0 2 ) -t- rc(M 4 3 .3Si0 2 ) = 3M 2 SiO s + wM'Si f 8 
 
 AERATED "WATERS. (See CARBONIC ACID and WATER.) 
 
 AEROX.ITE. (See METEORITE.) AEROSXTE. (See PYRARGYRITE.) 
 
 AESCHirTCXTE. (Handwork d. Chem. i. 192.) A mineral occurring at Miask in 
 the Ural, and consisting, according to Hart wall's analysis, of 56 titanic acid, 20 
 zirconia, 15 eerie oxide, 3*8 lime, 2'6 ferric oxide, 0'5 stannic oxide (making together 
 97*9), but according to Hermann's more recent analysis, of 25-90 titanic acid, 33*20 
 columbic acid, 22*20 eerie oxide, 5*12 cerous oxide, 5'45 ferrous oxide, 6'22 oxide of 
 lanthanum, 1-28 yttria, and 1'20 water ( = 100'57). By its crystalline form and 
 properties, as well as by its chemical constitution, it appears to be closely related 
 to Polymignite, Polycrase, Euxenite, &c. 
 
 AESCUI.ETXN- or ESCUXETXW. C 9 IP0 4 , or C 18 H*0*. A product of the de- 
 composition of sesculin, discovered in 1853 by Kochleder and Schwartz (Ann. Ch. 
 Phai-m. Ixxxvii. 186; Ixxxviii. 356), and independently by Zwenger (ib. xc. 63). 
 It is obtained^ 1. By boiling sesculin with hydrochloric or dilute sulphuric aeid. The 
 liquid on cooling deposits a crystalline mass which, when washed with cold water, 
 dissolved in hot alcohol, and treated with acetate of lead, yields a lead-compound of 
 sesculetin from which the latter may be separated by hydrosulphuric acid. 2. A 
 cold saturated solution of asculin mixed with emulsin (the fermenting principle of 
 sweet almonds) and left in a warm place, deposits after a while, small crystals of 
 cesculetin. 
 
 Asculetin forms shining needles or scales which are bitter, sparingly soluble in 
 cold water and alcohol, more soluble in the same liquids when warm, but nearly in- 
 soluble in ether. The aqueous solution is fluorescent like that of aesculin (q. v.), but 
 in a much less degree ; the fluorescence is however considerably exalted by addition 
 of a small quantity of carbonate of ammonium. 
 
 When gradually heated, it gives off 6-64 p.c. water at 100, melts above 270, and 
 then distils with decomposition. Hydrochloric acid dissolves it without alteration ; 
 nitric acid converts it into oxalic acid. It is also decomposed by hot concentrated 
 sulphuric acid. It dissolves in alkalis, forming solutions of a fine gold-yellow colour ; 
 its solution in boiling aqueous ammonia deposits on cooling a yellow substance, which 
 decomposes rapidly in contact with the air. .ZEsculetin imparts a dark green colour 
 to ferric salts. It reduces nitrate of silver at the boiling heat ; precipitates red oxide 
 of copper from cupric salts dissolved in potash ; and forms with acetate of lead a yellow 
 precipitate containing C 9 H 4 Pb 2 O 4 . 
 
 AESCVXiXC ACXX>. Obtained as a white precipitate by boiling saponin (a 
 substance contained in the horse-chesnut and in many other plants) with dilute hydro- 
 chloric or sulphuric acid, or by boiling saponin with potash-ley and decomposing the 
 resulting sesculetate of potassium with an acid. It is insohible in water, but soluble 
 in alcohol, and is deposited therefrom in granular crystals on cooling. Nitric acid 
 
60 AESCULIN-AGALMATOLITE. 
 
 transforms it into a yellow resinons nitro-compound. It is but a weak acid. The 
 alkaline aesculates are soluble in water, and crystallise from solution in alcohol. 
 The formula of sesculic acid, according to Fremy (Ann. Ch. Phys. [3] Iviiii. 101) is 
 CPH^O 12 . Bolley (Ann Ch. Pharm. xc. 211), who calls it sapogcnin, assigns to it 
 the formula C 12 H 18 5 . According to Kochleder and Schwarz (Ann. Ch, Pharm. 
 Ixxxviii. 357) it is identical with chinovatic acid C 6 H 10 2 . 
 
 AESCUXIiff or ESCULIW. C 21 H 24 13 , or <? 42 # 2 '6> 26 . (Gerh. ir. 291, Hand- 
 wort. d. Chem. i. 196.) A crystalline fluorescent substance obtained from the bark 
 of the horse-chestnut (Aesculus Hippocastanum) and of other trees of the genera 
 Aesculus and Pavia. It was first observed by Frischmann, more closely investigated by 
 Trommsdorff the younger in 1 835 (Ann. Ch. Pharm. xiv. 198), afterwards byRochleder 
 and Schwarz (ibid. Ixxxvii. 186 ; Ixxxviii. 156), and by Zwenger (ibid. xc. 63). 
 
 The aqueous extract of the bark is precipitated with acetate of lead ; the precipitate 
 is washed, suspended in water, and decomposed by hydrosulphuric acid ; and the liquid 
 is filtered at the boiling heat. Or better : the aqueous extract is mixed with solution 
 of alum and excess of ammonia ; the liquid filtered to separate the fawn-coloured pre- 
 cipitate of alumina mixed with the colouring matter of the bark ; the yellowish filtrate 
 neutralised with acetic acid and evaporated to dryness ; the residue containing the 
 sulphates and acetates of potassium and ammonium, boiled with a little strong alcohol 
 to extract the aesculin ; the alcoholic filtrate evaporated till it crystallises ; and the 
 sesculin thus obtained, is purified by pressure between bibulous paper, and recrystallisa- 
 tion. (Kochleder, J. pr. Chem. Ixxi. 414 ; Chem. Gaz. 1858, 96.) 
 
 Aesculin forms colourless, needle-shaped crystals. It is inodorous, has a bitter 
 taste, is sparingly soluble in cold water and alcohol, more soluble in the same liquids 
 at the boiling heat, and nearly insoluble in ether. 
 
 Aesculin is coloured red by chlorine ; it forms a yellow precipitate with subacetate 
 of lead, and reduces the protoxide of copper to suboxide, like glucose. It melts at 160 ' 
 and decomposes at a somewhat higher temperature, yielding various products among 
 which is a small quantity of sesculetine. Boiled with hydrochloric or dilute sulphuric 
 acid, it is resolved into sesculetin and glucose : 
 
 = C 9 H 6 4 + 2C 6 H 12 8 
 
 The aqueous solution of sesculin is highly fluorescent (see LIGHT), the reflected light 
 being of a sky-blue colour. Nearly the same fluorescent tint is exhibited by an in- 
 fusion of horse-chestnut bark. The colour is however slightly modified by the presence 
 of another fluorescent substance, paviin, recently discovered by Prof. Stokes (Chem. 
 Soc. Qu. J. xi. 17). The latter is separated from sesculin by its greater solubility in 
 ether. Its solution exhibits a blue-green fluorescence. Aesculin and paviin appear to 
 exist together in the barks of all species of the genera Asculus and Pavia, aesculin 
 being however more abundant in the former and paviin in the latter (see PAVHN). 
 The fluorescence of both sesculin and paviin is augmented by alkalis, but destroyed by 
 acids. 
 
 AETHAXi. (See CETYL.) 
 
 AETHER, AETHYX., &c. (See ETHEE, ETHYL, &c.) 
 
 AETHXOPS. An old pharmaceutical term applied to various mineral preparations 
 of black colour or approaching thereto : e. g. Aethiops antimonialis obtained by 
 triturating together mercury, sulphide of antimony, and sulphur ; Aethiops martialis 
 black oxide of iron ; Aethiops mineralis, black sulphide of mercury obtained by tritu- 
 rating mercury with sulphur; Aethiops narcoticus (or hypnoticus,} sulphide of mer- 
 cury obtained by precipitation ; Aethiops per se, the grey powder obtained by exposing 
 impure mercury to the air. 
 
 AETHOXIRRIW. The yellow colouring matter of the flowers of Antirrhinum 
 lAnaria. 
 
 AFFINITY. (See CHEMICAL AFFINITY.) 
 AFTOXTXTE. (See APHTONITE.) 
 
 AGAXiftlATOXiXTE [from &ya\fj.a, an image ; and \i6os, stone] ; Bildstein. 
 This name was originally given to a soft mineral or rather a number of such 
 minerals used by the Chinese for carving grotesque figures and idols. These minerals 
 vary in colour from greyish-green to yellow and red ; they are all more or less soft 
 and unctuous to the touch and capable of being cut and polished. 
 The Chinese agalmatolites are of three kinds : viz. 
 1. Hydrated silicates of aluminium and potassium : 
 
 a. 9Si0 2 .3Al 4 3 .lK 2 0.3H^O = GSi0 3 .3Al 2 3 .lK0.3HO 
 6..3Si0 2 .lAl 4 3 .M 2 0.1H 2 = 
 
 M denotes potassium, sodium, calcium, magnesium, &c. 
 
AGAR-AGAR AGARICUS. 61 
 
 2. Hydrated silicates of aluminium. 
 
 a. 9Si0 2 .2Al 4 O s .6H 2 = 3Si0 3 .lAP0 3 .3HO 
 b. 15Si0 2 .4Al 4 3 .4H 2 = 58iO t .24PO t .ZHO 
 
 3. Hydrated silicates of magnesium : 
 
 15Si0 2 .12Mg 2 0.4H 2 = 5Si0 3 .QMg0.2HO 
 
 There are also several European minerals which in composition and physical cha- 
 racter closely resemble the Chinese agalmatolites. 
 
 4. Agalmatolite from Magyag in Hungary has the same composition as the Chinese 
 mineral, 1, a. 
 
 5. Agalmatolite, from Ochsenkopf in the Saxon Harz, and Orikosin from Posseggen 
 in Salzburg, have a composition expressed by the formula : 
 
 9Si0 2 .3Al 4 3 .2M 2 0.3H 2 = 6Si0 3 .3Al 2 3 .2M0.3HO. 
 
 6. Mother of Diaspore, a mineral in which the diaspore of Schemnitz in Hungary is 
 intergrown, has the composition 2, a above. 
 
 7. Parophite from Canada has a composition corresponding to the formula : 
 
 9Si0 2 .3Al 4 O s .3M 2 0.4fH 2 = 6Si0 3 .3AP0 3 .MOAHO 
 
 8. Dysyntribite, from Diana and other localities in St. Lawrence county, New York, 
 appears also to have a constitution resembling that of the agalmatolites. 
 
 9. Kaolin, which is a hydrated silicate of aluminium, containing 
 
 (2Si0 2 .Al 4 3 .2H 2 0) = 4Si0 3 .3Al?0 3 .6HO, 
 exactly resembles the agalmatolites in physical character. 
 
 10. Neolite, from Eisenach and other localities, containing 
 
 9Si0 2 .Al 4 O s .3M 2 O.H 2 = 6Si0 3 .lAF0 3 .3M0.1HO, 
 
 also forms masses resembling agalmatolite. 
 
 All these minerals have a specific gravity ranging from 2'75 to 2*85 ; rarely as high 
 as 2'90. In hardness, they are intermediate between gypsum and calcspar. They are 
 more or less translucent, unctuous to the touch, do not adhere to the tongue, and 
 are easily carved and wrought. 
 
 The true agalmatolites are 1, a; 4, 5, 6, and 7 : the rest may be regarded as allied 
 species. (Handw. d. Chem. i. 375.) 
 
 AGAPHITE. (See TURQUOISE.) 
 
 AG AR-AG AR, or Bengal Isinglass : a dried sea -weed from Singapore, consisting 
 of small transparent colourless strips, is almost completely soluble in water, and forms 
 a large quantity of thick, tasteless, and odoiirless jelly. 
 
 AGARICIW. (See AMANITIN.) 
 
 AGARICUS. A genus of the order Fungi. Many fungi, especially of the genus 
 Agaricus are commonly used as food, and it is remarkable that the amount of nitrogen 
 contained in their dried substance exceeds that in peas and beans, which are generally 
 regarded as the most nutritious of all articles of food. 
 
 The following table exhibits the percentage of nitrogen and of ash in various species 
 of fungi, as determined by Schlossberger andDoppi ng (Ann. Ch. Pharm. lii. 106 to 
 120). The plants were dried at 100 C. The quantity of water averaged about 90 
 per cent. 
 
 Nitrogen. Ash. 
 
 Agaricus deliciosus .... 4-68 6-9 
 
 arvensis 7-26 
 
 glutinosus . . . ,4'61 
 russula . . . . . . 4-25 
 
 cantharellus . . . . 3'22 
 
 muscarius . . . .6-34 
 
 Boletus aurens 4-7 
 
 Ly coper don echinatum . . . .6*16 
 Polyporus fomentarius .... 4-46 
 D&dalea quercina 3-19 
 
 19-82 
 4-8 
 9-5 
 
 11-2 
 9-0 
 
 6-80 
 6-2 
 3-0 
 
 The ash contains a large proportion of phosphates. The solid tissue of fungi, for- 
 merly regarded as a peculiar substance, fungin, is nothing but cellulose: it may be ex- 
 tracted by treating the fungi successively with water, weak soda-ley, hydrochloric acid, 
 and alcohol Agarics were found by Schlossberger and Dopping to contain mannite and 
 fermentable sugar, but no starch. The acid contained in agarics and other fungi was 
 formerly supposed to be of peculiar nature, and called boletic cxfungic acid; but it 
 has been shown by Bolley and Dessaignes that many agarics contain fumaric acid, some- 
 times associated with malic, citric, and phosphoric acid. 
 
62 AGATE AGROSTEMMINE. 
 
 AGARXC17S XtfXXTERAXiXS, the mountain milk, or mountain meal, of the Ger- 
 mans, is one of the purest of the native carbonates of lime, found chiefly in the clefts of 
 rocks, and at the bottom of some lakes, in a loose or semi-indurated form. 
 
 The name of mineral agaric, or fossil meal, was also applied by Fabroni to a stone of 
 a loose consistence found in Tuscany in considerable abundance, of which bricks maybe 
 made, either with or without the addition of a twentieth part of clay, so light as to iloat 
 in water, and which he supposes the ancients used for making their floating bricks, 
 This, however, is very different from the preceding, not being even of the calcareous 
 ;enus, since it appears, on analysis, to be a hydrated silicate of magnesium mixed with 
 id a small quantity of iron. Kirwan calls it argillo- 
 
 alumina, and a small quantity of iron. Kirwan calls it argillo-murite. 
 
 AGATE. A mineral, whose basis is calcedony, blended with variable proportions 
 of jasper, amethyst, quartz, opal, heliotrope, and carnelian. Ribbon agate consists of 
 alternate and parallel layers of calcedony with jasper, or quartz, or amethyst. The 
 most beautiful comes from Siberia and Saxony. It occurs in porphyry and gneiss. 
 Brccciatcd agate ; a base of amethyst, containing fragments of ribbon agate, constitutes 
 this beautiful variety ; it is of Saxon origin. Fortification agate, is found in nodules 
 of various imitative shapes, imbedded in amygdaloid. This occurs at Oberstein on 
 the Ehine, and in Scotland. On cutting it across and polishing it, the interior zig-zag 
 parallel lines bear a considerable resemblance to the plan of a modern fortification. In 
 the very centre, quartz and amethyst are seen in a splintery mass, surrounded by the 
 jasper and calcedony. Mocha stone. Translucent calcedony, containing dark outlines 
 of arborisation, like vegetable filaments, is called Mocha stone, from the place, in Arabia, 
 where it is chiefly found. These curious appearances were ascribed to deposits of iron 
 or manganese, but more lately they have been thought to arise from mineralised plants 
 of the cryptogamous class. Moss agate, is a calcedony with variously coloured ramifi- 
 cations of a vegetable form, occasionally traversed with irregular veins of red jasper. 
 Dr. M'Culloch has detected, what Daubenton merely conjectured, in mocha and moss 
 agates, aquatic confervse, unaltered both in colour and form, and also coated with iron 
 oxide. Mosses and lichens have also been observed, along with chlorite, in vegetations. 
 An onyx agate set in a ring, belonging to the Earl of Powis, contains the chrysalis of 
 a moth. 
 
 Agate is found in most countries, chiefly in trap rocks and serpentine. Hollow 
 nodules of agate, called geodes, present interiorly crystals of quartz, colourless or 
 amethystine, having occasionally scattered crystals of stilbite, chabasite, and capillary 
 mesotype. These geodes are very common. Bitumen has been found by M. Patrin 
 in the inside of some of them, among the hills of Dauria, on the right bank of the 
 Chilca. The small geodes of volcanic districts occasionally contain water in their 
 cavities. These are chiefly found in insulated blocks of a lava having an earthy 
 fracture. When they are cracked, the liquid escapes by evaporation ; it is easily re- 
 stored by plunging them for a little in hot water. Agates are artificially coloured by 
 immersion in metallic solutions. Agates were more in demand formerly than at present. 
 They were cut into cups and plates for boxes ; and also into cutlass and sabre handles. 
 They are still cut and polished on a considerable scale and at a moderate price, at 
 Oberstein. The surface to be polished is first coarsely ground by large millstones of 
 a hard reddish sandstone, moved by water. The polish is afterwards given on a wheel 
 of soft wood, moistened and imbued with a fine powder of a hard red tripoli found in 
 the neighbourhood. M. Faujas thinks that this tripoli is produced by the decomposi- 
 tion of the porphyrated rock which serves as a gangue to the agates. The ancients 
 employed agates for making cameos (see CALCEDONY). Agate mortars are valued by 
 analytical chemists, for reducing hard minerals to an impalpable powder. 
 
 The oriental agate is almost transparent, and of a vitreous appearance. The occiden- 
 tal is of various colours, and often veined with quartz or jasper. It is mostly found 
 in small pieces covered with a crust, and often running in veins through rocks like 
 flint and petrosilex, from which it does not seem to differ greatly. Agates are most 
 prized when the internal figure nearly resembles some animal or plant. U. 
 
 AGEX>O*XXi. A name applied by Caventou to a crystaltisable substance obtained 
 from liquorice-root ; identical with asparagin. (Henry and Plisson.) 
 
 AGNESXTE. Syn. with BISMUTITE. 
 
 AGROSTEAHHIVTE. A crystalline basic substance obtained from the seeds of 
 the corn-cockle (Agrostemma Githago). The seeds are exhausted with weak alcohol 
 acidulated with acid ; the acid is concentrated by evaporation and mixed with magnesia; 
 and the dried precipitate is treated with alcohol. 
 
 Agrostemmin crystallises in pale yellow scales which are but slightly soluble in 
 water, but very soluble in alcohol, to which they impart an alkaline reaction. It is 
 decomposed by boiling potash, with evolution of ammonia. 
 
AIR ALANINE. 63 
 
 The sulphate, chloro-aurate and chloroplatinate of agrostemmine are crystallisable ; 
 the phosphate forms a bulky precipitate. (Schulze, Ann. Ch. Pharm. Ixvm. 350.) 
 
 AIKINITE. Syn. with ACICITLITE. 
 
 AIR. The term "air" (Latin, aer) is now exclusively employed to denote the com- 
 ponent gases of the earth's atmosphere. Amongst the older writers on science, we find 
 the word "air" made use of to designate the gaseous or aeriform condition of a body ; 
 thus carbonic acid gas was called "fixed air," hydrochloric acid gas "marine acid air, 
 hydrogen gas " inflammable air," &c. (See ATMOSPHERE.) 
 
 A JUG A REPTAHTS (Creeping Bugle). (Handw. d.Chem.i. 385.) This plant, 
 grown on the even ground of the Lechthal, yielded, when gathered in the beginning of 
 June, 84-3 p.c. water, and 10'4 p.c. ash (a) ; that which grew on the chain of hills ad- 
 joining the valley, yielded at the end of June, 81-6 p.c. water and 9'5 p.c. ash (6). 
 
 Potash 37*31 36-39 
 
 Soda , 
 
 Lime 23-73 
 
 Magnesia 10'70 
 
 Sesquioxide of iron . . . 279 
 
 Manganoso-manganic oxide . . trace 
 
 Phosphoric anhydride . . 5*46 
 
 Sulphuric . . . 3/63 
 
 Chloride of potassium . . o'04 
 
 Chloride of sodium .... 2'66 
 
 Silica. .... 8-61 
 
 4-81 
 15-70 
 5-43 
 1-70 
 2-29 
 5-51 
 3-68 
 
 2-78 
 21-71 
 
 AKANTXCON. (See EPIDOTE.) 
 AKCETHXar. (See ACETONE.) 
 AKIKXTE. (See ACHMITE.) 
 AK.OKTTITE. A variety of arsenical pyrites. 
 
 AXiABANDXN. (See MANGANESE-GLANCE.) 
 
 AXiAB ASTER. Granular gypsum, Albatre gypseux. The technical name for 
 granular gypsum or sulphate of calcium. Alabaster is among the several varieties of 
 gypsum what marble is among carbonates of calcium, and like marble is used for sculp- 
 ture, especially for objects of small dimensions. The hard, fine-grained, snow-white, 
 translucent alabaster from Volterra near Florence, is especially valued for these purposes. 
 
 AX.AX.XTE. (See DIOPSIDE.) 
 
 AXiAXOrxWE. C'IFNO 8 . (A. Strecker, Ann. Ch. Pharm. Ixxv. 29; Grin. ix. 
 
 434 ; G-erh.i. 678.) An organic base obtained by heating aldehyde-ammonia with 
 hydrocyanic acid in presence of excess of hydrochloric acid. 
 
 C 2 H 3 2 .NH* + CNH + HC1 + H 2 = C'H'NO 2 + NH'Cl. 
 
 To prepare it, an aqueous solution of 2 pts. aldehyde-ammonia is mixed with aqueous 
 hydrocyanic acid containing 1 pt. of the anhydrous acid, hydrochloric acid is added 
 in excess, and the mixture is boiled and afterwards evaporated to dryness over the 
 water-bath. The residue consisting of hydrochlorate of alanine and a large quantity 
 of sal-ammoniac, is digested in a little cold water, which leaves the greater part of 
 the sal-ammoniac undissolved ; the solution of hydrochlorate of alanine is boiled with 
 hydrate of lead, added in small portions as long as ammonia continues to escape ; the 
 liquid is filtered ; and the dissolved lead is precipitated from the solution by sulphu- 
 retted hydrogen. The filtered liquid yields crystals of alanine by evaporation, and 
 an additional quantity may be obtained from the mother-liquor by addition of alcohol. 
 Another and better method is to treat the mixture of hydrochlorate of alanine and 
 sal-ammoniac with alcohol and ether, in which the former only is readily soluble, con- 
 centrate the solution by evaporation, and remove the hydrochloric acid by boiling with 
 hydrate of lead. 
 
 Properties. Alanine crystallises on cooling from a hot saturated solution in colour- 
 less needles having the form of oblique rhombic prisms united in tufts. They have 
 a pearly lustre, are hard, and grate between the teeth. At 200, it sublimes and falls 
 down again in fine snowy crystals ; when rapidly heated, it melts and suffers partial 
 decomposition. It dissolves in 4-6 pts. of water at 17, and in a smaller quantity of 
 hot water ; it is very sparingly soluble in cold alcohol, and quite insoluble in ether. 
 The aqueous solution has a sweet taste, does not affect vegetable colours, and forms no 
 precipitates with any of the ordinary reagents. 
 
 Alanine is isomeric with urethane, lactamide, and sarcosine ; from the two former 
 it is distinguished by not melting below 100 ; from the last by being soluble in water, 
 and by its behaviour with metallic oxides. 
 
64 ALANINE-ALBUM GR^ECUM. 
 
 Decompositions. Alanine is not altered by boiling with dilute acids, or with alkalis. 
 It dissolves in strong sulphuric acid, and the solution does not blacken on boiling. 
 Fused with hydrate of potassium, it gives off hydrogen and ammonia, and yields 
 cyanide and acetate of potassium. When its aqueous solution is boiled with peroxide 
 of lead, it is resolved into aldehyde, carbonic anhydride, and ammonia : 
 CH 7 N0 2 + = C 3 H 4 + CO 2 + NH 3 . 
 
 The aqueous solution is also decomposed by nitrous acid, with evolution of nitrogen 
 and formation of lactic acid : 
 
 C S H 7 N0 2 + N0 2 H = C 3 H 6 S + 2N + H 2 0. 
 
 Alanine. Nitrous Lactic 
 
 acid. acid. 
 
 _ Compounds of Alanine. Alanine acts both as a base and as an acid. It unites 
 directly with acids, and when boiled with metallic oxides forms compounds consisting 
 of alanine with 1 atom of hydrogen replaced by a metal. With hydrochloric acid, it 
 forms two compounds, viz. 2C 3 H 7 N0 2 .HC1, obtained by treating alanine with dry hydro- 
 chloric acid gas, and C 3 H 7 N0 2 .HC1, produced by evaporating a solution of alanine 
 in excess of hydrochloric acid. Both these compounds dissolve readily in water, 
 sparingly ^in alcohol; the latter is very deliquescent, but may with some difficulty be 
 obtained in crystals. On mixing a solution of alanine in hydrochloric acid with excess 
 of bichloride of platinum, and evaporating, the chloroplatinate, 2C 3 H 7 N0 2 .HCl.PtCi ;i , 
 crystallises in slender yellow needles, soluble in water and alcohol, and even in a 
 mixture of alcohol and ether. Nitrate of alanine, C 3 H 7 N0 2 ,HN0 3 is obtained by 
 evaporating a solution of alanine in dilute nitric acid, in long colourless needles, which 
 deliquesce in damp air, and dissolve very readily in water, less in alcohol; at 100, 
 they turn yellow and decompose. Sulphate of alanine is very soluble in water, and 
 remains as a syrupy mass when its solution is evaporated ; it may be washed with 
 cold alcohol. It is not precipitated from its aqueous solution by alcohol, but a mixture 
 of ether and alcohol separates it in the form of a thick syrup. 
 
 The copper-compound of alanine, 2C 3 JFCuN0 2 + H 2 crystallises from a solution 
 of alanine which has been boiled with cupric oxide, in dark blue needles and thicker 
 rhombic prisms. It forms a dark blue solution in water, but is nearly insoluble in 
 alcohol. The crystals remain unaltered at 100, but at 120 they give off water, 
 and are reduced to C 3 H 6 CuN0 2 assuming at first a lighter blue colour, and afterwards 
 crumbling to a bluish-white powder. The silver-compound, C 3 H 6 AgN0 2 , is obtained 
 in a similar manner, and separates as the liquid cools, in small yellow needles united 
 in hemispherical groups. They assume a darker colour when exposed to light, and 
 also when heated to 100 in the moist state; but when dry they sustain that tempe- 
 rature without alteration. A solution of nitrate of silver mixed with alanine, yields 
 by spontaneous evaporation, colourless rhombic tables, which are decomposed by heat, 
 with slight detonation, and leave a residue of spongy silver. A lead-compound, 
 C 3 H 6 PbN0 2 .PbHO, is obtained in colourless glassy needles, by boiling protoxide of 
 lead in aqueous alanine, and evaporating and cooling the solution. It is also pre- 
 cipitated in radiating crystals, on mixing the aqueous solution with alcohol. The 
 crystals dried over sulphuric acid, give off water and crumble to a powder which is 
 no longer completely soluble in water. 
 
 (See INULIN.) 
 
 A white, crystalline, resinous substance extracted from gutta percha by 
 alcohol or ether. It is best obtained by treating gutta percha with ether, and digest- 
 ing the resulting extract with alcohol, which dissolves a yellow resin, and leaves a 
 white substance to which Payen gives the name of alban. After recrystallisation from 
 absolute alcohol, it forms a white pulverulent mass, which begins to melt at 100, is 
 perfectly fluid and transparent between 175 and 180, and contracts strongly in cool- 
 ing. It dissolves with facility in oil of turpentine, benzol, sulphide of carbon, ether, 
 hot alcohol, and chloroform, and separates from the solutions in the crystalline form. 
 The crystals are wetted by watery liquids. They exhibit with sulphuric acid the same 
 reactions as native gutta percha. (Payen, Compt. rend. xxxv. 109.) 
 
 AXiBENE. A name given by Volckel to a white substance which, according to 
 his observations, remains undissolved when melam is boiled with water. Volckel 
 assigns to this substance the composition C H 9 N 10 0* (Ann. Ch. Phys. [2] Ixii. 90). 
 
 (See APOPHYLUTE.) 
 
 Soda-felspar. (See FELSPAB.) 
 ALBUM GRJECUIVT. An obsolete name for the excrements of the dog, formerly 
 used as a remedy in medical practice. The substance contains about 79 per cent, of 
 phosphate of calcium. 
 
ALBUMIN. 65 
 
 (Gerh. iv. 433 ; L eh m a nn, Physiological Chemistry i. 330; also 
 Zoochemie in G-melin'sHandbuch, Bd. viii. Pelouze et Fremy, Traite deChimie 
 generale, vi. 67.) Albumin is the chief and characteristic constituent of white of egg 
 and of the serum of blood, and occurs in all those animal substances which supply 
 the body or individual parts of it with the materials required for nutrition and 
 renovation. It forms about 7 p. c. of blood and 12 p. c. of white of egg ; it is a principal 
 constituent of chyle, lymph and of all serous fluids. It occurs also in the juice of 
 flesh, in the brain, the pancreas, the amniotic liquid, and generally in a greater or 
 smaller quantity in all the liquids (transudates) effused from the blood-vessels into 
 the cellular tissues of the organs, into the cavities of the body, or on to the surface. 
 It is found in the solid excrements of man and of other animals, the quantity in- 
 creasing in disorders of the mucous membrane of the intestinal canal. It is not 
 found in normal urine, but is present in that liquid in many states of disease, espe- 
 cially in affections of the respiratory organs, which interfere with the process of 
 oxidation. 
 
 Albumin exists in two very distinct modifications, viz. the soluble form, in which 
 it always occurs in the animal body, and the insoluble form, into which it may be 
 brought by the action of heat, as when white of egg or blood-serum is boiled. These 
 two modifications of albumin are identical in chemical composition, the difference 
 between them being due, partly, perhaps, to peculiarity of molecular aggregation, but 
 chiefly to the presence of certain mineral salts which are always associated with the 
 soluble variety. In fact, albumin does not occur in the animal body in the free 
 state, but in the form of an alkaline albuminate ; white of egg, serum, and all liquids 
 which contain albumin, leave, when incinerated, an ash chiefly consisting of alkaline 
 carbonate. Insoluble albumin does not appear to exist in the living animal organism, 
 unless indeed, fibrin may be regarded as coagulated albumin, which is by no means 
 improbable, inasmuch as there is no exact method of distinguishing between the two. 
 
 Preparation. Albumin may be prepared either from white of egg, or from blood- 
 serum. White of egg consists of transparent thin-walled cellules, enclosing an alkaline 
 solution of albuminate of sodium. On beating it up with water, the cellular sub- 
 stance separates in pellicles, while the albuminate of sodium remains in solution, 
 together with chloride of sodium and phosphate of calcium. To remove these mineral 
 substances, the liquid, after being filtered from the cellular substance, is mixed with 
 a small quantity of subacetate of lead, which produces an abundant precipitate (an 
 excess of the lead-salt would redissolve it). The mass, after being washed, is stirred ' 
 up with water to the consistence of a paste, and carbonic acid gas is passed through 
 the liquid. The albuminate of lead is thereby decomposed, carbonate of lead remains 
 suspended in the liquid, and the albumin in the free state remains dissolved. The 
 solution is filtered through paper previously washed with dilute acid, and, as it still 
 retains traces of lead, it is treated with a few drops of aqueous hydrosulphuric acid, and 
 cautiously heated to 60, till it begins to show turbidity ; the first flocks of albumin 
 thus precipitated carry down the whole of the sulphide of lead. When the liquid 
 which after filtration is perfectly colourless, is evaporated in large capsules at 40, 
 a residue is obtained consisting of pure soluble albumin (Wurtz, Ann. Ch. Phys. 
 [3] xii. 27). The same method applied to the albumin of blood-serum does not yield 
 a pure product. 
 
 To obtain pure albumin in the coagulated state, white of egg, diluted with an equal 
 bulk of water, filtered, and reduced to its original volume by evaporation at 40, is 
 mixed with a strong solution of potash, whereby it is soon converted into a translu- 
 cent, yellowish elastic mass. This is divided into small portions and exhausted with 
 cold water as long as the water removes any alkali, the whole being kept as much 
 as possible from contact with the air. It is then dissolved in water or boiling alcohol, 
 and the solution is precipitated by acetic or phosphoric acid. The precipitate, after 
 washing, leaves no appreciable residue when incinerated. (Lieberkiihn.) 
 
 Properties. Soluble albumin, dried in the air, forms a pale yellowish, translucent 
 mass, easily triturated and reduced to a white powder. The specific gravity of the 
 albumin of the hen's egg, from which the salts had not been removed, was found by 
 C. Schmidt (Ann. Ch. Pharm. xi. 156-167), to be 1-3144, and after calculating 
 for the elimination of the salts, the density of pure albumin was found to be T2617. 
 It becomes electric by friction, and is tasteless, inodorous and neutral to vegetable 
 colours. It swells in water, assuming a gelatinous appearance ; it does not dissolve 
 freely in pure water, but very readily in water containing any alkaline salt. After 
 being dried in vacuo, or at a temperature below 50, it may be heated to 100 with- 
 out passing into the insoluble modification. Soluble albumin dried at 60 loses 4 p. c. 
 water at 140, remaining, however, soluble in water. 
 
 The aqueous solution of albumin deviates the plane polarisation of a ray of light 
 to the loft. It becomes opaline at 60, begins to deposit the albumen at 61 to 63, 
 
 VOL. I. F 
 
66 ALBUMIN. 
 
 nnd at a temperature a little higher the whole coagulates in a mass. When very 
 dilute, it becomes turbid without coagulating ; but if the liquid be then concentrated 
 by evaporation, it deposits the albumin in pellicles or flocks. 
 
 Coagulated albumin is white, opaque, elastic, and reddens litmus (Hruschauer, 
 Ann. Ch. Pharm. xlvi. 348). When dried, it assumes a yellow colour, and becomes 
 brittle and translucent like horn. When immersed in water, after drying, it gra- 
 dually absorbs about five times its weight of the liquid, and resumes its primitive 
 consistence. 
 
 When coagulated albumin is boiled in water for about 60 hours, it gradually dis- 
 appears, being transformed into a substance soluble in water, and consisting, ac- 
 cording to Mulder and Baumhauer (J. pr. Chem. xx. 346 ; xxxi. 295), of trioxide 
 of protein, C^H^N^ 8 (C = 50-98 p. c. ; H = 6-69; and S = 5'01 ; N = 27'32). 
 Coagulated albumin, heated to 150 with a small quantity of water in a sealed tube, 
 gradually forms a limpid solution, which has no longer the property of coagulating by 
 heat. (L. Gmelin.) 
 
 Albumin is insoluble in alcohol and in ether. Strong alcohol added in large excess, 
 precipitates albumin from its aqueous solution in the same state as when it is 
 coagulated by heat; but the precipitate produced by a small quantity of weak 
 alcohol redissolves completely in water. When alcohol is added to a somewhat dilute 
 solution of albumin, so as to render it slightly opaline, the liquid after a while, 
 solidifies in a jelly, which, however, is again liquefied by heat. Coagulated serum, 
 or white of egg, may be made to dissolve in alcohol by the addition of a little alkali. 
 (Scherer.) 
 
 Ether shaken up with a solution of albumin coagulates but a small portion of it ; 
 if, however, the albuminous solution is concentrated, it thickens so much as to appear 
 coagulated. Albumin is not acted upon by oils either fixed or volatile. 
 
 Nearly all acids precipitate albumin from its solutions. Nitric acid precipitates 
 it with peculiar facility, and may therefore be used as a test of the presence of 
 soluble albumin. Strong hydrochloric acid aided by heat dissolves coagulated albu- 
 min, forming a blue or violet solution, which turns brown when boiled in an open 
 vessel, and according to Bopp (Ann. Ch. Pharm. Ixix. 30) yields chloride of am- 
 monium, leucine, tyrosine, and other products of unknown composition. With aqua 
 regia, albumin yields both chlorinated and nitro-compounds. 
 
 Strong sulphuric acid coagulates albumin by the heat which is evolved when the 
 " two liquids come in contact. Dilute sulphuric acid precipitates albumin after some 
 time only, not however combining with it, as the acid may be completely removed 
 from the precipitate by washing. 
 
 Tribasic phosphoric acid, acetic, tartaric, and most other organic acids do not form 
 precipitates in moderately concentrated solutions, of albumin ; but when either of these 
 acids is added in excess to a highly^ concentrated solution of serum or white of egg, the 
 liquid solidifies in the cold to a jelly which liquefies like gelatin when heated, and 
 again forms a gelatinous mass on cooling. The aqueous solution of this jelly remains 
 perfectly transparent when boiled, but it is precipitated by a neutral salt of either of 
 the alkali-metals. (Lieberkiihn.) 
 
 When a small quantity of acetic acid is added to white of egg or serum, so as just 
 to saturate the alkali, and the liquid is then largely diluted with water, flocks of 
 albumin are deposited after awhile. If the supernatant liquid be then decanted, 
 and the precipitate treated with a small quantity of solution of nitre or common 
 salt, it immediately dissolves, and the solution is coagulated by boiling. (Scherer.) 
 Serum or white of egg mixed with a certain quantity of common salt or other 
 salt of an alkali-metal, forms a liquid precipitable by phosphoric, acetic, tartaric, 
 oxalic, lactic acid, &c. Conversely, a solution of albumin (or other albuminoidal sub- 
 stance) in acetic acid is precipitated by the salts of the alkali-metals. The precipi- 
 tation is greatly facilitated by heat, and likewise takes place with greater facility 
 as the proportion of salt added is greater. The precipitate dissolves in pure water, 
 with greater facility in proportion as less heat has been applied in producing it ; 
 the solution is not coagulated by heat. It is soluble also in acetic acid, phosphoric 
 acid, and even in alcohol, provided it has not been altered by desiccation, or by 
 contact with the air. The aqueous solution is precipitated by certain salts, ferro- 
 cyanide of potassium, for example. 
 
 Dried soluble albumin suspended in acetic, tartaric, or citric acid, swells up and is 
 converted into coagulated albumin, which may be completely freed from acid by 
 washing. Acetic, tartaric, and tribasic phosphoric acid dissolve coagulated albumin 
 when heated with it. Arsenious acid does not combine with albumin. Chlorine and 
 bromine precipitate albumin. 
 
 Alkalis do not in general precipitate albumin from its solutions ; but a strong 
 solution of potash added in considerable quantity to a solution of albumin, forms a 
 
ALBUMIN. 
 
 67 
 
 gelatinous mass of albuminate of potassium. Dilute solutions of potash and soda 
 mix with albumin in all proportions, and on boiling the liquid, an alkaline sulphide is 
 formed. When albumin is heated with hydrate of potassium melted in its water of 
 crystallisation, the water being renewed as it evaporates, ammonia and hydrogen 
 are evolved, leucine and tyrosine are produced, together with oxalate, butyrate 
 valerate, &c. of potassium. Alkaline carbonates added to a solution of albumin prevent 
 its coagulation by heat. Coagulated albumin digested at a gentle heat with neutral 
 carbonate or acid carbonate of sodium, displaces the carbonic acid, and forms with the 
 alkali a compound, which, after washing, is perfectly neutral to test paper, but leaves 
 when incinerated a considerable quantity of alkaline carbonate. 
 
 Albumin subjected to dry distillation yields water, carbonate of ammonium, 
 hydrosulphate of ammonium, volatile alkalis of undetermined composition, empyreu- 
 matic oils, &c. Coagulated albumin putrifies when left in contact with water, yielding 
 valeric and butyric acids, a crystalline body having a penetrating odour, an oily 
 acid, and a substance which dissolves in hydrochloric acid, producing a liquid of 
 beautiful violet colour and yielding tyrosine, together with other products (Bopp, Ann. 
 Ch. Pharm. Ixix. 30). The oxygen of the air has no action on serum or white of egg. 
 Recently extracted serum left for a fortnight in contact with oxygen in a tube 
 standing over mercury absorbs but a very small quantity of the gas, and does not 
 form carbonic acid. 
 
 Albumin distilled with a mixture of peroxide of manganese and sulphuric acid 
 yields acetic, propionic, butyric, and benzoic aldehydes, together with formic, acetic, 
 butyric, valeric, and benzoic acids, and probably also propionic and caproic acids. 
 Nearly the same products are obtained by distilling albumin with sulphuric acid and 
 acid chromate of potassium, this mixture yielding in fact, hydrocyanic acid, a heavy oil 
 having the odour of cinnamon, cyanide of tetryl (valeronitrile), also . benzoic, acetic 
 and butyric acids, with small quantities of formic, caproic and propionic acids, and of 
 benzoic and propionic aldehydes (Gruckelberger, Ann. Ch. Pharm. Ixiv. 39). Al- 
 bumin does not decompose oxygenated water. 
 
 Composition of Albumin. Albumin obtained from various animal fluids exhibits 
 the same composition, as shown by the following analyses : 
 
 From White of Egg. 
 
 Carbon 
 
 Hydrogen 
 
 Nitrogen 
 
 Oxygen 
 
 Sulphur 
 
 "Wurtz's analysis was made with soluble, the rest with coagulated albumin. Mulder 
 supposes that albumin contains also 0*4 per cent, phosphorus. Most of the preparations 
 with which the above analyses were made, contained small quantities of phosphorus 
 in the form of phosphate of calcium. 
 
 From Blood-serum. 
 
 ' 
 
 
 Dumas 
 
 
 
 ^ 
 
 Mulder. 
 
 Scherer. 
 
 and Cahours. 
 
 Rilling. 
 
 Wurtz. 
 
 Liebeikuhn. 
 
 . 53-4 . 
 
 . 54-3 . 
 
 . 53-4 . 
 
 . 53-4 . 
 
 . 52-9 
 
 . . 53-3 
 
 . 7-0 . 
 
 . 7-1 . 
 
 . 7-1 . 
 
 . 7'0 . 
 
 . 7'2 
 
 . . 7-1 
 
 . 157 . 
 
 . 15-9 . 
 
 . 15-8 . 
 
 . 
 
 . 15-6 
 
 . . 15-7 
 
 . 
 
 . . 
 
 . . 
 
 
 
 22-1 
 
 
 
 
 1-7 to 1-8 . 
 
 
 1-8 
 
 Dumas and Cahours. Mulder. Ruling. Scherer. 
 
 Carbon 
 
 53-3 
 
 
 53-5 . . 53-4 
 
 
 53-1 
 
 
 54-5 
 
 Hydrogen 
 
 7-1 
 
 
 7-3 . . 7-1 
 
 
 7-0 
 
 
 7-0 
 
 Nitrogen 
 
 157 
 
 
 15-8 . . 15-6 
 
 
 . . 
 
 
 157 
 
 Oxygen . 
 Sulphur . 
 
 
 
 
 .'.' .' .' 1-3 
 
 
 1*3 
 
 
 
 Mulder supposes that blood-albumin contains also 0*3 per cent, phosphorus. Ruling 
 found the amount of sulphur in eight analyses to vary from 1-29 to 1*39 per cent. 
 
 Scherer. Weidenbusch. Baumhauer. 
 
 
 a 
 
 b 
 
 c 
 
 rf 
 
 e 
 
 Carbon 
 
 54-2 . . 
 
 54-1 . . 
 
 54-0 
 
 . . 53-3 . . 
 
 54-3 
 
 Hydrogen . 
 Nitrogen 
 
 7-1 . . 
 15-5 . . 
 
 7-2 . . 
 15-8 . . 
 
 7-0 
 15-8 
 
 . . 7-0 .. 
 . . 157 . . 
 
 7'1 
 15-8 
 
 
 
 
 
 
 
 Sulphur 
 
 
 
 
 
 
 a from a hydrocele ; b from a congestion-abscess ; c from pus ; d from flesh of 
 poultry ; e from the flesh of fish. 
 
 From these and other analyses, Liebig deduces the formula C 2 ' 6 H 338 N 5I S 3 68 Mulder, 
 c > H m N *2 S0 8o. Lieberkiihn, C"H I1 *N 18 S0 22 . Each of these formulae gives numbers 
 
 F 2 
 
68 ALBUMIN. 
 
 agreeing nearly with the analytical results. Mulder regards albumin as a compound 
 of (hypothetical) protein with (hypothetical) sulphamide, viz. : 
 
 C 90 H 139 N 22 S0 80 = 5C 18 H 27 N 4 8 + N-II 4 S 
 
 Protein. Sulphamide. 
 
 Liebig's formula is intended merely to express in a simple form certain relations 
 between albumin and other animal substances. Lieberkiihn, on the other hand, 
 regards his formula as actually expressing the composition of the molecule of albumin 
 as it exists in the metallic albuminates (q. v.) 
 
 According to Lebonte and Groumoens ( J. Pharm. [3] xxiv. 17) albumin is not 
 a pure proximate element, but a mixture of two bodies, one of which is insoluble in 
 glacial acetic acid, while the other dissolves in that acid and is precipitated therefrom 
 by potash. 
 
 The properties of albumin vary in some degree with the source from which it is 
 derived. The differences may in some cases be attributed to the presence of different 
 mineral substances ; but in others they are of such a nature as rather to point to 
 the existence of different modifications of albumin. Thus, Fremy and Valen- 
 ciennes have found (Ann. Ch. Phys. [3] 1. 138) that the albumin of the eggs of 
 certain tribes of birds exhibits peculiar modifications. That from the eggs of 
 different species of gallinaceous birds always exhibits the characters above described ; 
 but the eggs of swimming and wading birds yield an albumin which, when diluted 
 with 3 measures of water, is not coagulated by heat, but is precipitated by nitric acid ; 
 and the albumin from the eggs of predaceous birds, and of some kinds of perching 
 and climbing birds is neither coagulated by heat nor precipitated by nitric acid. 
 The composition was, however, found to be the same in all cases. 
 
 Blood-albumin exhibits the same reactions as that from white of egg, excepting that 
 the latter when boiled gives up part of its sulphur in the form of sulphuretted 
 hydrogen, which blood-albumin does not ; nevertheless coagulated white of egg 
 appears to contain more sulphur than blood-albumin. 
 
 Paralbumin. Scherer found in a liquid obtained from a case of ovarian dropsy, 
 a substance resembling albumin, but differing from it in not being completely preci- 
 pitated by ebullition, even after addition of acetic acid, and in dissolving in water 
 after being precipitated by alcohol. Metalbumin is the name given by the same 
 chemist to another supposed modification of albumin, likewise obtained from a pa- 
 thological fluid, which exhibited similar peculiarities to the preceding, and was 
 further distinguished by giving no precipitate with hydrochloric acid, or with ferro- 
 cyanide of potassium after acidulation with acetic acid. 
 
 Other substances more or less resembling albumin are : globulin or crystallin 
 existing in blood-globules and in the crystalline lens of the eye ; hcematocrystattin, a 
 crystalline body obtained from blood, and vitellin, existing in the yolk of eggs (see 
 these substances). 
 
 Quantitative Estimation of Albumin. The best mode of precipitating albumin 
 from alkaline liquids (serum, for example), for quantitative estimation, is to neutralise 
 or slightly acidulate the liquid with acetic acid, and then coagulate the albumin by 
 boiling. The precipitate thus obtained is flocculent and may be easily collected on 
 a filter and washed, the liquid passing through perfectly 1 clear, whereas if the albumin 
 be 'coagulated by heat alone, it is very apt to clog the filter. Another reason for 
 using the acetic acid is, that mere boiling does not precipitate the albumin completely 
 from alkaline solutions. The precipitated albumin, after being thoroughly washed, 
 may be dried in vacuo over sulphuric acid or in a current of warm air. 
 
 Uses of Albumin. Albumin is much used for clarifying vinous and syrupy liquids, 
 inasmuch as, when boiled with them, it coagulates, and takes hold of the colouring 
 matter and other impurities, thereby removing them, and carrying them to the bottom 
 or to the surface of the liquid, according to its density. In cookery, white of egg 
 is employed for this purpose, but in large operations, such as sugar-refining, the 
 serum of blood is used. Albumin is applied to a considerable extent for fixing 
 colours in calico-printing ; it is also used in photography. Its property of forming a hard 
 compound with lime renders it very useful for making cement for laboratory pur- 
 poses and for mending broken earthenware. A paste made of white of egg and 
 slaked lime, acquires after a while the hardness of stone. 
 
 ALBUMINATES. (Lassaigne, Ann. Ch. Phys. [3] Ixiv. 90 ; Lieberkiihn, J. Pharm. 
 [3] xxxiii. 398 ; Lehmann, Physiol. Chem. i. 332; Grerh. iv. 447.) Albumin is a 
 weak acid, and apparently dibasic. Its compounds with the alkalis are soluble and 
 are obtained directly by treating albumin with caustic alkalis or alkaline carbonates. 
 The other albuminates are insoluble and are obtained bv precipitation. 
 
 Albuminate of Barium, C 72 H MI BaN li) S0 22 + IPO (?) A solution of albuminate 
 
ALBUMIN. 69 
 
 of potassium in dilute alcohol forms with barium-salts, a precipitate which, dries 
 up to a white powder, insoluble in water, alcohol and ether. White of egg mixed 
 with caustic baryta, strontia or lime, forms an insoluble compound, which becomes 
 very hard when dry. 
 
 Albuminate of Copper, C 72 H 1IO Cu 2 N 18 S0 82 + H 2 (?) Obtained in like manner 
 forms when dry, a green, brittle mass, insoluble in water and alcohol. Acids deco- 
 lorise, but do not dissolve it (Lieberkiihn). According to Lassaigne, double albu- 
 minates of copper with potassium, or barium, or calcium, may be obtained by 
 heating hydrate of copper with solution of albumin and solution of potash, baryta or 
 lime. There is also an albuminate of copper and magnesium which is insoluble 
 and has a lilac colour. 
 
 Albuminate of Lead is a white insoluble salt, obtained by mixing the solution of 
 albumin and subacetate of lead ; it is soluble in excess of the lead-salt, and is decom- 
 posed by all acids. 
 
 Mercuric Albuminate is a white substance obtained by precipitating corrosive 
 sublimate with albuminate of sodium (white of egg). It is insoluble in pure water, 
 but soluble in saline liquids ; for this reason, when white of egg is \ised as an antidote 
 in cases of poisoning by corrosive sublimate, endeavours should always be made 
 to produce vomiting ; otherwise a portion of the mercuric albuminate may remain 
 dissolved in the gastric juice, which contains chloride of sodium. 
 
 Albuminate of Potassium, C 72 H 110 K-N 18 SO- 2 + H 2 0. Prepared by mixing a con- 
 centrated solution of white of egg with strong potash-ley, and washing the result 
 ing gelatinous mass with cold water, as long as any alkali dissolves out, then dissolving 
 the residue in boiling alcohol, and precipitating by ether. After drying, it is no longer 
 soluble in boiling alcohol or in water. The aqueous solution is not coagulated by 
 boiling or by addition of alcohol. With a small quantity of acetic, tartaric, citric 
 or phosphoric acid, it yields an abundant white precipitate easily soluble in excess of 
 acid. These characters are the same as those of casein ; hence, Gerhardt considers 
 it probable that casein may be really albuminate of potassium. 
 
 Albuminate of Sodium is contained in blood-serum and in white of egg, together 
 with chloride of sodium and phosphate of calcium. Serum and white of egg have 
 a slight alkaline reaction, are more soluble in water than pure albumin, and when 
 boiled, coagulate in a gelatinous mass, not in flakes. After boiling, the filtered liquid 
 is more alkaline than before, and still contains albuminate of sodium, whereas the 
 coagulum is free from alkali. Hence, Gerhardt thinks it probable that serum 
 and white of egg contain an acid albuminate of sodium, C 72 H 1H NaN 18 S0 8 -, 
 which is decomposed by heat into the neutral albuminate, and free albumin which 
 separates from the liquid. This view is, moreover, in accordance with the composition 
 of dried white of egg, which, according to Lehmann's analysis, contains 1-6 per cent. 
 of soda, the formula C 72 H ni NaN 18 SO'- 2 + H 2 requiring 1-8 per cent. White of egg 
 or serum treated with strong caustic soda, yields a gelatinous mass nearly insoluble 
 in cold water, and closely resembling the compound produced under the same cir- 
 cumstances by potash. This gelatinous salt appears to be the neutral albuminate of 
 sodium, C 72 H 110 Na 2 N 18 S0 22 + H 2 0. It contains, according to Lehmann, 3'14 per cent. 
 soda (by calculation 37). 
 
 Albuminate of Silver, C 78 H 110 Ag 2 N 18 S0 22 + H 2 (?) Obtained by precipitation. 
 White, flocculent, blackens when exposed to light. 
 
 Albuminate of Zinc, C 72 H 110 Zn 2 N 18 S0 2 * + H*0 (?) White powder insoluble in water, 
 alcohol, and ether. 
 
 , VEGETABLE. (Gerh. iv. 444; Handw. d. Chem 2 te Aufl. ii. 
 147.) -7 Most vegetable juices contain a substance which appears to be identical in 
 composition and properties with the albumin of blood or of white of egg. The 
 same compound appears also to exist in the solid form in certain parts of plants, 
 especially in the seed. Vegetable juices containing albumin deposit it, when heated 
 to 65 or 70, in flocks, which are often coloured greenish by chlorophyll, and contain 
 tatty and waxy substances mechanically enclosed. To remove these matters, the 
 coagulum must be washed, first with water, then with boiling alcohol and with ether. 
 
 Albumin is especially abundant in tbe juice of carrots, turnips, cabbages, and 
 the green stems of peas, but it is more easily prepared from potatoes, by cutting 
 them into Alices, covering them with very dilute sulphuric acid (of 2 p.c.), leaving the 
 liquid to itself for 24 hours, then adding fresh potatoes, and repeating the same 
 operation once more, afterwards neutralising the solution with potash, and boiling. 
 A considerable quantity of albumin is then deposited in thick white flocks. 
 
 Wheat-flour also contains a considerable quantity of albumin, which may be ex- 
 tracted with cold water. For this purpose, the water which runs off in washing the 
 paste of wheat-flour for the preparation of gluten (q. v.) is left at rest till the stai-ch 
 
 F 3 
 
70 ALBUMINOIDS. 
 
 is completely deposited; the clear liquid is then heated to the boiling point, where- 
 upon it deposits a small quantity of albumin ; on evaporating the solution a larger quan- 
 tity is obtained. 
 
 Oleaginous seeds likewise contain albumin, which may be extracted by beating 
 the seeds with water into an emulsion, extracting the fat by agitation with ether, and 
 the albumin by boiling. 
 
 When sweet almonds which have been freed from their envelopes are reduced 
 to a pulp by rasping, and the pulp is digested for a few minutes in boiling water, 
 the sugar, gum, and the greater part of the legumin contained in the almonds enter 
 into solution ; and on depriving the residue of fatty matter by means of ether, 
 nothing is left but coagulated albumin, exhibiting the same characters as coagulated 
 white of egg. 
 
 a b c de 
 
 Carbon . 54-0 . 637 . 51-9 to 52-0 . 53-1 . 52-0 
 
 Hydrogen . 7'8 . 7'1 . 6-9 . 7-0 . 7*2 . 6-8 
 
 Nitrogen . 15'8 . 157 . 18-4 ......... 
 
 Oxygen .......... ...... 
 
 Sulphur ............. 0-97 . 079 . 1-0 . 077 
 
 a, albumin from rye,analysed by Jones (Ann. Ch. Pharm. xl. 66) ; b, from wheat- 
 flour, by Dumas and C ah onrs (Ann. Ch. Phys. [3] vi. 309); c, from wheat-flour 
 byBoussingault (ibid. [2] Ixiii. 225); d, from potatoes by Killing (Ann. Ch. 
 Pharm. Iviii. 306) ; e, from peas by Killing; /, g, from rye, by Mulder. 
 
 Vegetable albumin is distinguished from legumin (vegetable casein) by being 
 coagulated by heat, and not precipitated by acetic acid. It exhibits the same re- 
 actioHS as animal albumin with acids, alkalis, tannin, chloride of mercury, &c. The 
 mode of its occurrence differs, however, remarkably from that of animal albumin in 
 this respect, that it is always found in plants in neutral or acid liquids, whereas animal 
 albumin exists only in alkaline liquids (p. 25). 
 
 The albumin of sweet almonds is remarkable for the facility with which it decom- 
 poses, and by its property of acting as a ferment, and determining the metamorphosis 
 of amygdalin, salicin, and other organic bodies. This altered albumin is distinguished 
 by the terms emulsion and synaptase (q. v.~) 
 
 The myrosin of mustard-seeds likewise resembles vegetable albumin. Lastly, the 
 diastase of germinated barley, beer-yeast, and wine-lees are likewise albuminoidal 
 substances in a state of alteration. 
 
 . Oonin. (Handw. d. Chem. 2 te Aufl. i. 404.) The name given by 
 Couerbe to the substance of the cells which enclose the white of birds' eggs. It is 
 obtained by exposing white of egg for a month to temperature between and 8, in 
 the form of a white filmy substance, which when dried is white, translucent in thin 
 laminae and easily friable. It does not contain nitrogen, and consequently does not 
 evolve ammonia when heated. It is insoluble in water, whether hot or cold, but swells 
 up in hot water, forming a gummy mass. It is not acted upon by alcohol, ether, or 
 acetic acid. Nitric and sulphuric acids decompose it. It dissolves in hydrochloric 
 acid, and on adding water to the solution, a white powder is precipitated. It dis- 
 solves in caustic potash, forming a solution which is rendered turbid by acids, but not 
 precipitated. 
 
 ALBUMINOIDS. Protein-compounds. Blutbilder. (Gerh. iv. 430 ; Handw. 
 d. Chem. 2 te Aufl. ii. 120.) This term is applied to a class of compounds which 
 play an important part in the functions of animal and vegetable life. Three of them, 
 albumin, casein, and. fibrin are distinguished by well-marked characters. 
 
 Fibrin separates spontaneously in t,he solid form from blood, soon after its removal 
 from the living body ; albumin is contained in the serum or more liquid portion of 
 the blood, and separates from it as a coagulum on the application of heat; and 
 casein is contained in milk, from which it may be separated, not by heat, but by the 
 addition of an acid. The same substances are found in plants, viz. fibrin, in the grain 
 of wheat and other cereal plants ; albumin in most vegetable juices, and casein (or 
 legumin) in the seeds of the pea, bean and other leguminous plants. 
 
 The other bodies of this class are less distinctly characterised ; indeed, most of 
 them appear to be mere modifications of the one or other three above-mentioned : 
 thus, syntonin, 'the essential constituent of the muscular fibre, closely resembles 
 blood-fibrin ; vik llin, a substance occurring in the yolk of eggs, is scarcely distin- 
 guishable from albumin ; and f/lolni.li.n and hfematocn/stallin, two substances con- 
 tained in the blood, resemble albumin in the property of coagulating by heat. 
 
 Moreover, albumin, fibrin, and casein, though clearly distinguished from one 
 another by the different conditions under which they pass from the liquid to the 
 
ALBUMINOIDS. 71 
 
 solid state, nevertheless possess many characters in common. They all dissolve in 
 caustic potash or soda, and when boiled with those alkalis, yield solutions from which 
 acids precipitate them in a more or less altered state, and at the same time eliminate 
 hydrosulphuric acid. When subjected to diy distillation, they all give off ammonia 
 (or compound ammonias). They all decompose and putrefy with great facility when ex- 
 posed to moist air, and in that form are very active as ferments ; thus, yeast, wine-less, 
 diastase, &c., are merely albuminoidal substances in a peculiar state of decomposition. 
 All albuminoids treated with oxidising agents, such as mixtures of peroxide of 
 manganese or acid chromate of potassium and sulphuric acid, yield the same products, 
 viz. acids and aldehydes of the acetic and benzoic series (see AXBUMIN, p. 67). Albu- 
 minoids dissolve in very strong hydrochloric acid, forming a solution which is yellow 
 if kept from contact with the air, but assumes a fine blue or violet colour on exposure 
 to the air. A solution of mercury in an equal weight of nitric acid imparts to these 
 bodies a very deep red colour, this test serving to detect the presence of 1 part 
 of albumin in 100,000 parts of water. 
 
 All the albuminoids exhibit the same or nearly the same constitution. In the 
 living organism, albumin, fibrin, and casein are constantly being converted one into 
 the other. The casein of milk supplies the material for the formation of albumin 
 and fibrin ; and conversely, albumin and fibrin are converted into casein. Indeed, 
 the analyses of different bodies of the class do not differ from one another more than 
 analyses of the same body from different sources or by different experimenters. They 
 contain 50 to 54 p. c.- carbon, about 7 p. c. hydrogen, 15 to 17 p. c. nitrogen, about 25 p. c. 
 oxygen, and from 0*9 to 1 P 8 sulphur. According to some analyses, however, fibrin 
 contains rather less carbon and more nitrogen than albumin. Albumin and fibrin 
 have been supposed by some chemists to contain also a small quantity of phosphorus 
 as an organic constituent, but its existence is not well established. Most albuminoids 
 are associated with small quantities of mineral substances, including phosphate of cal- 
 cium, which cannot be separated from the organic matter by acids. 
 
 This great similarity of composition and properties exhibited by these bodies has 
 led to various views of the relation between them. Mulder supposed that all the 
 albuminoids contain the same organic group, C 18 H 27 N 4 6 , which he called protein, 
 combined with different quantities of sulphur and phosphorus, and that the con- 
 version of one of these bodies into the other depends upon the assumption or elimina- 
 tion of small quantities of one or both of those elements (see PROTEIN). Mulder 
 also stated, that when an albuminoid is treated with caustic alkali, the sulphur and 
 phosphorus are removed and the protein remains. The researches of other chemists 
 have shown, however, that this view is untenable. Neither of the albuminoids 
 contains phosphorus, and the proportion of sulphur appears to be the same in them 
 all : at all events, fibrin and egg-albumin, which perhaps exhibit the greatest dif- 
 ference of physical and chemical properties, do not differ perceptibly in amount of 
 sulphur. Moreover, the sulphur of albuminoids cannot be completely extracted by the 
 action of alkalis, so that the existence of the so-called protein is merely hypothetical. 
 Gerhardt was of opinion that all the albuminoids are identical, not only in com- 
 position, but in chemical constitution, and that they differ from one another only 
 in molecular arrangement, and by the nature of the mineral substances with which 
 they are associated ; in fact, that they contain a common proximate element which, 
 like many other organic compounds, is capable of existing in a soluble and in an 
 insoluble modification. Designating this common element by the name albumin, he sup- 
 posed that white of egg and serum consist of acid albuminate of sodium (p. 99), which is 
 separated by heat into free albumin and neutral albuminate of sodium, the latter remain- 
 ing dissolved ; that casein, which is soluble and non-coagulated by heat, consists of 
 neutral albuminate of potassium, from which the organic compound may be precipitated 
 by neutralising the alkali with an acid ; and that fibrin is albumin in the insoluble state, 
 more or less mixed with earthy phosphates. This view is in accordance with the fact 
 that fibrin and casein may be dissolved in neutral potassium-salts (better with addi- 
 tion of a little caustic alkali), forming a liquid which coagulates by heat, and deflects the 
 plane of polarisation of a luminous ray to the left, like albumin ; and that fibrin and 
 albumin, dissolved in a certain quantity of caustic alkali, exhibit the characters of 
 soluble casein. Nevertheless, it is possible to obtain the albuminoids in some cases 
 wholly, in others very nearly, free from mineral matters, and nevertheless exhibiting 
 their _ distinguishing characteristics. Moreover, it is certain that all these bodies 
 contain the same proportions of carbon, nitrogen, and sulphur. 
 
 Strecker (Handw. d. Chem. 2 te Aufl. ii. 124) supposes the albuminoids to be 
 composed of a great number of radicles (a supposition in accordance with the variety 
 of their products of decomposition) ; that the greater number of these radicles are the 
 same in all hence their great similarity, but that each contains one or more 
 such radicles peculiar to itself. Thus, when casein is converted in the animal body 
 
 F 4 
 
72 ALCOHOL. 
 
 into albumin and fibrin, it may take the radicles required for that transformation 
 from the other constituents of the milk, viz. the fat and the sugar. (See ALBUMIN, 
 BLOOD, CASEIN, CRYSTALLINE, FIBRIN, GLOBULIN, H^EMATOCRYSTALLIN, LEGUMIN, 
 MILK, VITELLIN.) 
 
 AXiBUiraiXTOBZi. This term is applied by Bouchardat to a product of the decom- 
 position of animal fibrin by very dilute hydrochloric acid (see FIBRIN), and by Mialhe, 
 to a peculiar substance into which he supposes albumin to be converted by the action 
 of the gastric juice before it is assimilated. 
 
 ALC AR.R./V.ZAS. Very porous vessels of slightly burnt clay used in hot climates 
 for cooling water and other liquids. The liquid oozes through the pores and stands 
 on the outside of the vessel in a sort of dew, which rapidly evaporates, especially if 
 the vessel is exposed to a current of air, and thereby cools the liquid. 
 
 AIiCH&lVTIXiXiA VUXiCARIS. 100 pts. of the fresh plant contain, according 
 to Sprengel : 76'0 pts. water, 10*3 pts. extractable by water, and 7 '8 by dilute potash- 
 ley; 5-6 woody fibre and l - 66 ash free from carbonic acid. The ash contained in 
 100 pts. ; 30-5 potash, 2-4 soda, 33'6 lime, 4'9 magnesia, 0'9 alumina, 14-4 silica, 
 4-4 sulphuric anhydride, 5 '4 phosphoric anhydride, 3 '5 chlorine, and traces of the 
 oxides of iron and manganese. 
 
 ALCOHOL. C 2 H 6 = C 2 H 5 .H.O [or C 4 H0* = &IPO.HO.']. This compound, 
 which is the spirituous or intoxicating principle of wine, beer, and other fermented 
 liquors, may be regarded as the hydrate or hydrated oxide of ethyl, or as a molecule of 
 water, HHO, in which half the hydrogen is replaced by the radicle ethyl, C' 2 H 5 . It has also 
 been regarded as a compound of ethyl ene and water, C 2 H 4 .H 2 0. 
 
 History. Intoxicating drinks produced by fermentation of vegetable juices contain- 
 ing sugar, have been known from the earliest times ; but it was not till the twelfth 
 century that the method of obtaining pure spirit of wine or hydrated alcohol from 
 these liquids by distillation, was discovered by Abucasis ; and the dehydration of this 
 liquid was first partially effected by means of carbonate of potassium by Eaimond 
 Lullius in the thirteenth century. The mode of obtaining perfectly anhydrous alcohol 
 was afterwards discovered by Lowitz. 
 
 Formation. 1. By the decomposition of glucose (grape-sugar) under the influence 
 of ferments, that is to say, of nitrogenous organic substances, such as yeast, which are 
 themselves undergoing decomposition. The sugar is then resolved into alcohol and 
 carbonic anhydride : 
 
 C 6 H i2 6 = 2C-'H 6 + 2CO*. 
 
 Other kinds of sugar, cane-sugar for example, as well as starch, woody fibre and 
 other vegetable substances, also yield alcohol under the influence of ferments, but they 
 are first converted into glucose. 
 
 2. From ethylene or olefiant gas, by addition of the elements of water : 
 C 2 H 4 + H 2 = C 2 H 6 0. 
 
 Olefiant gas briskly agitated for a long time with strong sulphuric acid, is absorbed, 
 and on diluting the liquid with water and distilling, alcohol passes over. This mode 
 of formation, first observed by Hennel (Phil. Trans. 1826, p. 240), haslately been con- 
 firmed and fully examined by Berthelot(Ann. Ch. Phys. [3] xliii. 385). As olefiant 
 gas can be obtained from inorganic materials, it follows that alcohol may be produced 
 without the agency of living organisms. 
 
 Preparation. 1. Of Hydrated or Aqueous Alcohol. When wine and other liquids 
 which have undergone the vinous fermentation are distilled, alcohol passes over together 
 with a considerable quantity of water ; and by subjecting the product to repeated dis- 
 tillations, spirit is obtained continually richer in alcohol, because the alcohol, being 
 more volatile than the water, passes over in larger quantity than the latter. But it is 
 not possible to remove the whole of the water by simple distillation. The residue of 
 the distillation, if continued long enough, is nothing but water containing small quan- 
 tities of acetic acid (produced by oxidation of the alcohol) and fusel oil. Portions of 
 these impurities also pass into the rectified spirit. The greater part of the acetic acid 
 however, and a considerable portion of the fusel oil are left in the residues of the 
 several distillations. The last portion of the acid is easily removed by distillation 
 over a small quantity of carbonate of potassium or wood-ashes : and the fusel oil, 
 which adheres more obstinately, and imparts a very unpleasant odour to the spirit, is 
 best removed by adding to the spirit about 07 of its weight of coarsely powdered 
 charcoal, leaving the mixture to stand for several days, and stirring it repeatedly, then 
 decanting and distilling. Bone-black or blood-charcoal may also be used. 
 
 2. Of Anhydrous or Absolute Alcohol. Alcohol cannot be completely dehydrated by 
 distillation, because, at the boiling-point of pure alcohol (78 C.), the vapour of water 
 possesses a considerable tension. The most highly rectified spirit obtained by frac- 
 
ALCOHOL. 73 
 
 tional distillation, still retains about 9 per cent, of water. The last portions of water 
 must be removed by the agency of some substance which has a powerful attraction for 
 it. Carbonate of potassium, chloride of calcium, and quick lime, are the substances 
 most commonly used for this purpose, more rarely acetate of potassium, sulphate of 
 copper, and other salts. 
 
 a. By Carbonate of Potassium. Highly rectified spirit is shaken up with ignited 
 carbonate of potassium, which forms a watery or pasty layer at the bottom. The 
 alcohol, whose density is thereby lowered to 0'815, is poured off into a distilling vessel 
 containing twice the quantity of pulverised and recently ignited carbonate of potassium, 
 left to stand for 24 hours, and then two-thirds of it are distilled off (Lowitz). This 
 method does not however remove the last minute portions of water. b. A more com- 
 plete dehydration is effected by chloride of calcium. The salt f used or dehydrated by 
 a heat of 400 C. is added in thick lumps to twice its weight of spirit containing 90 per 
 cent, of real alcohol ; and the mixture left for some days in a closed vessel and occa- 
 sionally shaken up, after which it is distilled in a retort over a fresh quantity of fused 
 chloride of calcium. The retort is heated in a sand or oil bath with its neck directed 
 upwards to prevent the contents from spirting over. When the quantity of alcohol 
 is large, a second treatment with chloride of calcium is necessary to effect complete 
 dehydration. 
 
 c. By Quick lime. A retort is two-thirds filled with small pieces of quick lime, and a 
 quantity of 90 per cent, spirit poured in sufficient to nearly cover the lime. The lime 
 soon slakes and becomes heated ; the mixture is left to digest for some hours ; and the 
 anhydrous alcohol is then distilled off in the water-bath. The distillation must be care- 
 fully conducted, otherwise the distillate will be contaminated with lime. Alcohol con- 
 taining fusel oil acquires a very unpleasant odour when treated with lime. This is by 
 far the easiest method of obtaining absolute alcohol. 
 
 d. When aqueous alcohol is enclosed in a bladder, and exposed to warm air, the 
 water gradually percolates through the bladder and evaporates, and absolute alcohol is 
 left inside. (Sommering.) 
 
 Alcohol may be regarded as anhydrous if sulphate of copper previously burnt white 
 does not acquire any blue colour when immersed in the alcohol in a close vessel (Cas- 
 soria), or if it forms a perfectly clear mixtxire with benzol (G-6'rgeu). It is doubtful 
 however whether either of these tests will indicate the presence of a very minute 
 quantity of water. 
 
 Properties. Alcohol is a transparent, colourless, very mobile liquid, having a strong 
 refracting power. Its specific gravity, according to Kopp (Pogg. Ann. Ixxii. 1), is 
 0792 at 20 ; or 07939 at 15-5, or 0-8095 at 0. If its volume at C. be taken for 
 unity, the volume at any temperature t is given by the formula : 
 
 v = 1 + 0-00104139* + 0-0000007836;! 2 + 0-000000017618* 3 . 
 and therefore for the temperatures : 
 
 ()C. 5C. 10 C. 15 C. 20 C. 25 C. 30 C. 
 
 the volumes of a given quantity of alcohol are as the numbers : 
 1-00000 1-00523 1-01052 1-01585 1*02128 1-02680 1-03242 
 
 Alcohol has never been reduced to the solid state, but becomes viscid at very low 
 temperatures, as when it is surrounded with a mixture of solid carbonic acid and 
 ether under an exhausted receiver. It boils at 78'4C. (173'1 Fah.) when the baro- 
 meter stands at 076 met. (G-ay-Lussac, Kopp.) Vapour-density = 1-613 (Gray- 
 Lussac); by calculation, for a condensation to 2 volumes, it is 1-591 when referred to 
 
 air as unity, and 23 when referred to hydrogen as unity [ - ^ = 23. ) 
 
 Alcohol has an en-livening odoiir and a burning taste, and when unmixed with water 
 exerts a poisonous action. It is a very slow conductor of electricity. 
 
 Decompositions. 1. By Heat. Alcohol- vapour passed through a red-hot glass or por- 
 celain tube yields carbonic anhydride, water, hydrogen, marsh-gas, olefiant gas, naphtha- 
 lin, empyreumatic oil and a deposit of charcoal. If the tube be filled with fragments of 
 pumice-stone, the solid and liquid products consist of nalphthalin. benzol, hydrate of 
 phenyl, acetic acid (?) and aldehyde, together with a number of solid compounds of not 
 very definite character, some of them smelling like musk, others like garlic (Berthelot, 
 Ann. Ch. Phys. [3] xxxiii. 285). Alcohol-vapour does not undergo decomposition at 
 300 C. in a tube containing fragments of porcelain, but gives off gas even at 220, if the 
 tube contains spongy platinum. (Reiset andMillon, Ann. Ch. Phys. [3] viii. 280.) 
 
 2. By Electricity. Absolute alcohol scarcely conducts the voltaic current, but when 
 potash or potassium is dissolved in it, decomposition takes place, hydrogen being 
 
74 ALCOHOL. 
 
 evolved at the negative pole and aldehyde-resin formed at the positive pole. 
 (Connell.) 
 
 3. By Oxygen. Alcohol is very inflammable, and burns in the air with a dull blue 
 flame, yielding water and carbonic acid. It does not readily deposit soot, even when the 
 supply of air is limited, but absolute alcohol deposits it more readily than ordinary spirit. 
 Alcohol- vapour mixed with air explodes by contact with flame or by the electric spark. 
 
 Imperfect Combustion. When alcohol or its vapour comes in contact with air, and 
 at the same time with platinum or certain other metals, an imperfect oxidation of the 
 alcohol takes place, the metal being generally heated to redness, and the alcohol being 
 converted, partly into carbonic acid and water, partly into aldehyde, acetic acid, formic 
 acid, acetal, and a peculiar compound having an excessively pungent odour. Some 
 metals excite this action at ordinary temperatures, others only when more or less 
 heated; but in all cases the action is more powerful as the metal is more finely divided 
 and consequently exposes a larger surface to the alcohol- vapour. The most powerful 
 action is exerted by platinum black. When this substance is shaken on paper mois- 
 tened with alcohol, it makes a hissing noise and becomes red-hot, sometimes setting 
 fire to the alcohol, or else continuing to glow, and inducing the slow combustion above 
 mentioned. If the platinum be previously moistened with a small quantity of water, 
 or at once covered completely with alcohol, the ignition is prevented, and the slow 
 combustion induced with greater certainty. If a number of watch-glasses containing 
 moist platinum black, be placed above a dish containing alcohol, and a bell jar open at 
 top inverted over them, the alcohol turns sour in a few weeks, and is found to contain 
 aldehyde, acetal, acetic acid, and acetic ether. 
 
 This action of platinum black affords an excellent means of discovering the presence 
 of alcohol in the air or in watery liquids. The liquid, neutralised, if necessary, with 
 alkali, to prevent the escape of volatile acids, is introduced into a retort, into the neck 
 of which, and near the bulb, is thrust a little boat containing platinum black, and on 
 each side of this boat is placed a piece of litmus paper, in contact with the platinum. 
 The retort is then gently heated in the water-bath, when, if alcohol is present, 
 its vapour will be converted into acetic acid by contact with the platinum black and 
 the paper will be reddened (Buchheim). [Other volatile organic liquids might exert 
 a similar action.] 
 
 Spongy platinum and clean platinum wire act in a similar manner to platinum black, 
 but not so quickly. If a coil of platinum wire be placed round the wick of a spirit- 
 lamp, the alcohol set on fire till the wire becomes red-hot, and the flame then blown 
 out, the wire will continue to glow and the alcohol- vapour to burn slowly, producing 
 acetic acid, aldehyde, &c. The same effect is produced by a ball of spongy platinum. 
 This is the lamp without flame, or glow lamp of Sir H. Davy. 
 
 4. By Chlorine. Chlorine gas is rapidly absorbed by alcohol, imparting to it a 
 yellow colour and causing considerable rise of temperature, which, if the liquid is ex- 
 
 Ced to light, may even cause it to take fire. At the same time it rapidly abstracts 
 irogen, which is partly replaced by chlorine, thereby producing hydrochloric acid, 
 aldehyde, acetal, acetic acid, acetate of ethyl, chloride of ethyl, and finally chloral. The 
 mixture of these substances, freed by washing with water from the soluble constituents, 
 was formerly called heavy hydrochloric ether. The formation of these several products 
 is represented by the following equations : 
 
 C'H'O + 2 Cl = C 2 H 4 -f 2 HC1 
 
 Alcohol. Aldehyde. 
 
 C 2 H 4 + 6 Cl = C 2 HC1 3 + 3 HC1 
 
 Aldehyde. 
 
 C 2 H0 + HC1 = C2H 5 C1 + H 2 
 
 Alcohol. 
 
 C'H 6 + H 2 + 4 Cl = C 2 H 4 2 + 4HC1 
 
 Acetic acid. 
 
 C 2 H'0 2 .C 2 H 5 + H 2 
 
 Alcohol. Acetic acid. Acetate of ethyl. 
 
 Acetate of ethyl may also be formed by the direct action of chlorine on the alcohol ; 
 thus : 
 
 2 C 2 H"O + 4C1 = C 2 H 3 2 .C 2 H 5 + 4 HC1 
 
 The acetal, which is probably formed at the beginning of the process, according to the 
 equation : 
 
 3C-H 6 + 2C1 = C 6 II 11 2 + H 2 + 2HC1, 
 
ALCOHOL. 75 
 
 is for the most part subsequently converted into acetic acid : 
 
 C 6 H 14 2 + 4H 2 + 10 01 = 3C 2 H 4 + 10HC1. 
 
 When the action of the chlorine is continued for a long time, chloral is always the 
 principal product. 
 
 Chlorine in presence of alkalis, converts alcohol into chloroform and carbonic 
 anhydride : 
 
 C 2 H 6 + 8C1 + = CHOP + 5HC1 + CO 2 . 
 
 The same products are formed by distilling dilute alcohol with hypochlorite of cal - 
 cium (chloride of lime, bleaching powder). (See CHLOROFORM.) 
 
 Bromine acts upon alcohol in a similar manner to chlorine, producing bromal, hydro- 
 bromic acid, bromide of ethyl, bromide of carbon, formic acid, and other products not 
 yet thoroughly examined. Iodine is at first dissolved by alcohol without decomposi- 
 tion, and forms a brown solution ; but after a while, hydriodic acid is produced, and 
 acting upon a portion of the alcohol, forms iodide of ethyl. An alcoholic solution of 
 potash treated with iodine yields iodoform and iodide of potassium, the former of which 
 compounds may be separated by water. 
 
 9. Chloric acid, in the concentrated state, sets fire to alcohol ; when diluted, it forms 
 acetic acid, the action being sometimes attended with evolution of chlorine. Perchlo- 
 ric acid mixes with alcohol without decomposition at ordinary temperatures, but the 
 liquid when heated first gives off alcohol, then ether, and ultimately white vapours 
 smelling like oil of wine, the residue at the same time turning black. 
 
 10. Strong Nitric acid decomposes alcohol, with great evolution of heat and brisk 
 ebullition, a mixture of various elastic fluids, the ethereal nitrous gas of the older 
 chemists, being evolved and an acid liquid remaining behind ; if the nitric acid is 
 dilute, the action does not take place without application of heat. Part of the nitric acid 
 unites directly with the alcohol, forming nitrate of ethyl, but the greater part is reduced 
 to nitrous acid which then forms nitrite of ethyl (nitrous ether) with a portion of the 
 alcohol, while the remainder of the alcohol is oxidised and converted into aldehyde, acetic 
 acid, formic acid, saccharic acid, oxalic acid, glyoxal, glyoxylic acid, and glycollic acid, 
 together with water and carbonic anhydride, which escapes as gas, together with nitric 
 oxide and the vapours of the more volatile among the compounds just mentioned. The 
 formation of glyoxal, glyoxylic acid, and glycollic acids is represented by the equations : 
 
 C 2 H 6 + 30 = C 2 H 2 2 + 2H 2 
 
 Glyoxal. 
 
 30 = C 2 H 4 3 + H 2 
 
 Alcohol. Glycollic acid. 
 
 C 2 H 2 2 + H- H*0 = C 2 H 4 4 
 
 Glyoxal. Glyoxylic 
 
 acid. 
 
 If urea be added to the mixture of nitric acid and alcohol so as to decompose the 
 nitrous acid as fast as it is formed (see UREA), the chief product of the action is nitrate 
 of ethyl N0 3 .C' 2 H 5 . Hydrocyanic acid has also been observed among the products of 
 the action of nitric acid upon alcohol. 
 
 When strong alcohol is heated with red fuming nitric acid (containing nitrous acid) 
 and nitrate of silver or mercuric nitrate is added, white fumes are given off, containing 
 aldehyde and other oxidised products, and a crystalline deposit of fulminate of silver 
 or mercury is formed, its production being due to the action of the nitrous acid on the 
 alcohol: e.g. 
 
 C 2 H 6 + 2 N0 2 Hg = C 2 N 2 Hg 2 2 + 3 H 2 
 
 Alcohol. Mercuric Fulminate 
 
 nitrite. of mercury. 
 
 But when a solution of mercury in nitric acid free from nitrous acid is added at a 
 temperature below 100 C. to alcohol of sp. gr. 0.8'44, no action takes place at first; but 
 on raising the temperature to 100, a white crystalline precipitate is formed, which is 
 a compound of mercuric nitrate with a nitrate of ethyl in which the whole of the hydro- 
 gen is replaced by mercury (Sobrero and Selmi; Grerhardt): 
 
 2 N0 3 H + 3 Hg 2 + C 2 H 6 = NOHg.NO s (C 2 Hg) + H 2 + 3 H 2 
 
 Crystalline compound. 
 
 11. Sulphuric acid forms with alcohol, a number of products varying in quantity 
 according to the proportions in which the two liquids are mixed, their degree of con- 
 centration, and the temperature to which the mixture is exposed. 
 
76 ALCOHOL. 
 
 Strong sulphuric acid mixes with alcohol, producing considerable evolution of heat, 
 and forms ethyl-sulphuric or sulphovinic acid, the acid being at the same time brought 
 to A greater state of dilution : 
 
 C 2 H 5 .H.O + SO.H = S0 4 .H.C 2 H 5 + H 2 
 
 Alcohol. Ethyl-su'phuric 
 
 acid. 
 
 When the strongest sulphuric acid (sp. gr. 1-825) is digested for some time at a 
 gentle heat, with excess of absolute alcohol, more than half the sulphuric acid is con- 
 verted into ethyl-sulphuric acid. If the acid or the alcohol is diluted with water, a con- 
 siderable quantity of the sulphuric acid remains unaltered. Sulphuric acid containing 
 1 at. water (S0 4 H 2 .H 2 0) forms ethyl-sulphuric acid only when heated. As the forma- 
 tion of ethyl-sulphuric acid is necessarily accompanied by that of water, a certain 
 portion of the sulphuric acid must always remain unconverted into ethyl-sulphuric 
 acid. 
 
 Formation of Ether. A mixture of 1 pt. alcohol, and from 1 to 2 pts. strong sulphu- 
 ric acid heated in a distillatory apparatus, boils between 120 and 140 C., at first giving 
 off ether, together with more or less undecomposed alcohol, then at 140 scarcely any- 
 thing but ether, at 160 ether and water, and at length when, in consequence of the 
 decomposition of the alcohol, the proportion of sulphuric acid has become excessive, 
 and the temperature rises above 160, the mixture blackens and gives off olefiant gas 
 together with sulphurous acid and other products hereafter to be mentioned. If how- 
 ever the alcohol be allowed to flow constantly into the vessel in a thin stream, so as to 
 maintain the proportion of 5 pts. alcohol to 9 pts. sulphuric acid, the temperature re- 
 mains constant at about 140, no sulphui-ous acid or olefiant gas is formed, but the 
 alcohol, as fast as it is supplied, is given off again in the form of ether and water. 
 
 The alcohol converts a molecule of sulphuric acid into ethyl-sulphuric acid and water, 
 as above : 
 
 C 2 H 5 .H.O + S0 4 .H 2 = S0 4 .C 2 H 5 .H + H 2 
 
 Alcohol. Sulphuric Ethyl-sulphuric Water, 
 acid. acid. 
 
 and the ethyl-sulphuric acid coming in contact with another molecule of alcohol, yields 
 ether and sulphuric acid : 
 
 S0 4 .C 2 H 5 .H + C 2 H 5 .H.O = (C 2 H 5 ) 2 + S0 4 H 2 . 
 
 Ethyl-sulphuric Alcohol. Ether. Sulphuric 
 
 acid. acid. 
 
 The sulphuric acid thus reproduced acts in like manner upon another molecule of 
 alcohol, and in this way the process continues as long as the supply of alcohol is kept 
 up. Etherification is therefore a continuous process, a given quantity of sulphuric 
 acid being capable of etherifying a very large quantity of alcohol. The water, how- 
 ever does not all pass off as it is formed, so that the sulphuric acid becomes continually 
 though slowly weaker, and consequently a continually larger quantity of alcohol passes 
 over undecomposed with the ether and water. 
 
 The explanation just given of the process of etherification is due to "Williamson 
 (Chem. Soc. Qu. J. iv. 106, 229). Its correctness is strikingly exhibited by the 
 analogous reaction which takes place between common alcohol and amyl-sulphuric acid. 
 When amyl-alcohol is dissolved in sulphuric acid, amyl-sulphuric acid is produced : 
 
 C 5 H".H.O + S0 4 H 2 = S0 4 .C 5 H".H + H 2 0. 
 
 Now, on heating this mixture and passing a stream of ordinary alcohol through it, as 
 above, ethamylic ether, or oxide of ethyl and amyl passes over first, then common 
 ether, and ethyl-sulphuric acid remains behind in place of amyl-sulphuric acid : 
 S0 4 .C 5 H".H + C 2 H 5 .H.O = C 2 H 3 .C 5 H n .O + S0 4 H 2 
 
 Amyl-sulphuric Alcohol. Oxide of ethyl Sulphuric 
 
 acid. and amyl. acid. 
 
 The sulphuric acid thus reproduced acts upon the ethyl-alcohol in the manner already 
 described, the products being ethyl-sxilphuric acid, ether, and water. The same products 
 are obtained by distilling a mixture of ethyl-alcohol and amyl-alcohol with sulphuric 
 acid. 
 
 The formation of ether from alcohol was formerly regarded as a simple process of 
 dehydration. Ether being regarded as C*H*0 and alcohol as its hydrate, C^H^O.HO, 
 it was supposed that the sulphuric acid simply abstracted the water and left the ether. 
 Against this view, however, it must be alleged that the quantity of water given off in 
 the distillation is very nearly equal to the whole quantity supposed to be separated 
 from the alcohol, which could not be the case if it were retained by the sulphuric acid. 
 Moreover, the molecule of ether referred to the same vapour- volume as that of alcohol. 
 
ALCOHOL. 77 
 
 C*H S 2 , is not C 4 H b O, but C 8 H 10 2 ', or, according to the atomic weights adopted in 
 this work, alcohol being C 2 H 6 0, ether is C 4 H 10 0. For these reasons, Mitscherlich, 
 Berzelius, and other chemists have regarded the action of sulphuric acid upon alcohol 
 as a, contact-action, or catalytic action, a mode of expression which simply states the fact 
 without explaining it. 
 
 Another objection to the views just mentioned, is that they take no account of the 
 formation of ethyl-sulphuric acid. That this, however, is an essential step in the process 
 of etherification is shown by the fact that, on distilling a mixture of alcohol and strong sul- 
 phuric acid, the quantity of ethyl-sulphuric acid constantly diminishes as the ether passes 
 over, and that, if the acid be diluted so far as not to form ethyl-sulphuric acid, the mix- 
 ture yields no ether by distillation. Liebig therefore supposed that the ethyl-sulphuric 
 acid is resolved at a certain temperature (120 to 140 C.) into ether, sulphuric acid, and 
 sulphuric anhydride : 
 
 2(C 2 H 5 .H.S0 4 ) = C 4 H'0 + S0 4 H 2 + SO 3 
 
 and that the sulphuric anhydride, uniting with water also present in the mixture, re- 
 produces sulphuric acid. But ethyl-sulphuric acid when heated alone gives off, not 
 ether but alcohol, even when heated to 140 or above in sealed tubes ; but when 
 heated with alcohol, it immediately yields ether. We are therefore led to regard the 
 formation of ether as a result of the mutual decomposition of alcohol and ethyl-sulphuric 
 acid, in the manner already explained. 
 
 When alcohol and strong sulphuric acid are heated together in sealed tubes, the 
 alcohol being in excess, a layer of ether forms on the top of the liquid, but no ethyl-sul- 
 phuric acid is found in the lower stratum. If the sulphuric acid is in excess, no ether 
 is formed (Graham, Chem. Soc. Qu. J. iii. 24). In the former case, it is probable that 
 ethyl-sulphuric acid was first formed, and afterwards converted by the excess of alcohol 
 into ether and sulphuric acid. Acid sulphate of potassium (Grr ah am) and various other 
 sulphates heated with alcohol in sealed tubes, also etherify it more or less completely, 
 the sulphate being in some cases converted into a basic salt. The alums, namely 
 common alum, ammonia-alum, potassio-ferric sulphate, and potassio-chromic sulphate 
 heated with an equal weight of 98 per cent, alcohol, etherify it completely. In all 
 these cases, the sulphate appears to give up a portion of its sulphuric acid, which then 
 acts on the alcohol as above. (Eeynoso, Ann. Ch. Phys. [3] xxviii. 385.) 
 
 Formation of Olefiant gas. When 1 pt. of alcohol is heated with 3 or 4 pts. of 
 strong sulphuric acid, the mixture begins, between 160 and 180 C., to blacken and 
 thicken, swells up considerably and gives off olefiant gas C 2 H 4 , together with variable 
 quantities of sulphurous anhydride, carbonic anhydride, carbonic oxide, oil of wine, 
 acetic acid, acetic ether and formic acid, and a black residue is ultimately left con- 
 sisting of a peculiar acid called thiomelanic acid and free sulphuric acid. By passing 
 alcohol- vapour through a boiling mixture of 10 pts. of strong sulphuric acid and 
 3 pts. of water, olefiant gas and water are obtained, with scarcely any coloration of 
 the mixture or formation of secondary products : 
 
 C 2 H 6 = C 2 H 4 + H 2 0. 
 
 12. Sulphuric anhydride, SO 3 , is dissolved by absolute alcohol, with evolution of heat, 
 and forms neutral sulphate of ethyl SO*.(C 2 H 5 ) 2 . When the vapour of the anhy- 
 dride is passed into absolute alcohol, crystals of sulphate of carbyl, C 2 H 4 .2S0 3 , are 
 formed, together with ethionic, isethionic, ethyl-sulphuric and sulphuric acids. 
 
 13. Phosphoric acid mixed with alcohol at ordinary temperatures, converts part of 
 it into ethyl-phosphoric acid. A mixture of phosphoric acid with a small quantity of 
 alcohol yields olefiant gas but no ether ; but if the alcohol is in excess, ether is first 
 given off, then olefiant gas and a thick acid distillate probably consisting of neutral 
 phosphate of ethyl, P0 4 .(C 2 H 5 ) 3 . Phosphoric anhydride absorbs the vapour of an- 
 hydrous alcohol, forming ethyl-phosphoric acid Pd 4 .C 2 H 5 .H 2 , and diethylphosphoric 
 acid, P0 4 .(C 2 H 5 ) 2 .H. Arsenic acid acts very much like phosphoric acid, producing 
 ether and ethyl-arsenic acid. Boric anhydride (vitrefied boric acid) in the state of 
 powder heated with absolute alcohol, gives off olefiant gas and leaves boric acid. 
 
 14. Hydrochloric acid gas is absorbed in large quantity by alcohol, and the solution 
 when heated gives off chloride of ethyl. The same compound is obtained by distilling 
 alcohol with strong hydrochloric acid, or with a mixture of common salt and sulphuric 
 acid ; but when a mixture of hydrochloric acid with a large excess of alcohol, either 
 anhydrous or hydrated, is heated to 240 in a sealed tube, ether is formed as well as 
 chloride of ethyl, these two liquids forming a layer on the surface, while the lower 
 stratum consists chiefly of water and hydrochloric acid. The ether results from the 
 action of alcohol on the chloride of ethyl already formed : 
 
 C 2 H 5 .C1 + C 2 H 5 .E.O = (C 2 IP) 2 + HO, 
 
78 ALCOHOL. 
 
 The same transformation takes place, though slowly, even at 100 C. (A. Key no so, 
 Ann. Ch. Phys. [3] xlviii. 385.) 
 
 15. Many metallic chlorides act upon alcohol in a similar manner to hydrochloric acid, 
 producing ether and chloride of ethyl. Chloride of zinc converts anhydrous alcohol 
 into chloride of ethyl with a small quantity of ether. "With hydrated alcohol, it yields 
 at 155C., ether and oil of wine, the quantity of which increases as the distillation goes 
 on ; hydrochloric acid is also given off, and basic chloride of zinc remains. When 
 dichloride of tin is distilled with a considerable quantity of alcohol, ether and chloride 
 of ethyl pass over between 140 and 170, afterwards a compound of chloride of ethyl 
 with dichloride of tin. (Kuhlmann, Ann. Ch. Pharm. xxxiii. 97, 192.) 
 
 Crystallised protochloride of tin distilled with alcohol yields ether, but no chloride 
 of ethyl (March and) ; the same decomposition takes place in a sealed tube at 240. 
 Crystallised chloride of manganese and protochloride of iron also etherify alcohol com- 
 pletely when heated with it in sealed tubes to 240; the chlorides of cadmium, nickel, 
 and cobalt partially ; in all these cases, the etherification takes place without blacken- 
 ing of the contents of the tube, and with little or no escape of gas when it is opened 
 (K ey noso, Ann. Ch. Phys. [2] xlviii. 385). The formation of ether in these reactions, 
 may be explained by the following equations, given by Williamson for the case of 
 chloride of zinc : 
 
 C 2 H 5 .H.O + ZnCl = C 2 H 5 .Zn.O 4 HC1. 
 
 C 2 H 5 .H.O 4- HC1 = C 2 H 5 .C1 + H 2 0. 
 
 C 2 H 5 .C1 + C 2 H 5 .Zn.O = (C 2 H 5 ) 2 + ZnCl. 
 
 With sesquichloride of iron, alcohol yields ether and chloride of ethyl between 130 
 and 140C., afterwards hydrochloric acid and water, the residue consisting of sesqui- 
 chloride of iron mixed with sesquioxide. With chloride of aluminium, chloride of 
 ethyl is given off between 170 and 200, afterwards hydrochloric acid, and alumina is 
 left behind. Trichloride and pentachloride of antimony convert alcohol into chloride 
 of ethyl, with a little ether, the residue consisting chiefly of oxychloride of antimony. 
 Protochloride of platinum boiled with alcohol of sp. gr. 0'813 to 0-893 is converted 
 into a black explosive powder called detonating platinum-deposit, C 2 H 4 Pt 2 0, the liquiJ 
 acquiring a strong acid reaction and the odour of chloride of ethyl : 
 
 C 2 H 6 + 2PtCl = C 2 H 4 Pt 2 4- 2HC1. 
 
 The chloride of ethyl is formed by the action of the hydrochloric acid on another por- 
 tion of the alcohol. (Zeise.) 
 
 Asolution of 1 pt. of dichloride of platinum in 10 pts. of alcohol of sp. gr. 0*823, dis- 
 tilled to |, yields aldehyde, chloride of ethyl, and hydrochlorie acid. The residual 
 dark brown liquid deposits a considerable quantity of the black detonating powder 
 just mentioned, and retains in solution the so-called inflammable chloride of platinum, 
 C 2 H 4 Pt 2 Cl 2 , according to Zeise, or C 2 H 3 Pt 2 Cl 2 , according to Liebig. Its formation 
 is represented by one of the following equations : 
 
 2C 2 H 6 + 2PtCl 8 = C 2 H 4 Pt 2 Cl 2 + C 2 H 4 + H 2 + 2HC1. (Zeise.) 
 
 Aldehyde. 
 
 3C 2 H 6 + 4PtCl 2 = 2C 2 H 3 Pt 2 Cl 2 + C 2 H 4 4- 2H 2 4- 4HCL (Liebig.) 
 
 Aldehyde. 
 
 The formation of the black deposit is not an essential part of the reaction, and in- 
 deed takes place most abundantly when the dichloride of platinum contains proto- 
 chloride. 
 
 Mercuric chloride, HgCl, dissolved in alcohol is slowly reduced to mercurous chloride 
 Hg 2 Cl. Potash added in excess to the alcoholic solution heated to 50C., forms an amor- 
 phous yellow precipitate containing carbon, hydrogen, oxygen and mercury, the hydrogen 
 being in smaller proportion than in alcohol. This precipitate heated to 200, explodes 
 without leaving any residue ; heated in the moist state, it decomposes less violently, 
 yielding mercury, water, and acetic acid (Sobrero and Selmi). Gerhardt and 
 Werther did not succeed in preparing this compound. 
 
 16. Trichloride of phosphorus readily decomposes alcohol, forming chloride of ethyl, 
 hydrochloric acid, tribasic phosphite of ethyl and phosphorous acid. (Be champ 
 Compt. rend ad. 944.) 
 
 6(C 2 H 5 .H.O) + 2 PCI 3 = 3C 2 H 5 C1 4- 3 HC1 4- P0 3 .(C 2 H 5 ) 3 + POMI 3 . 
 
 17. With pentachloride of phosphorus, the products are chloride of ethyl, hydro- 
 chloric and chlorophosphoric acid, PC1 3 O : 
 
 C 2 H 5 .H.O -t- PC1 3 .C1 2 = C 2 H 5 C1 4 HC1 T PCP.O. 
 
ALCOHOL. 79 
 
 18. Pentasulphide of phosphorus, on the other hand, converts alcohol, not into two 
 separate sulphides, but into the single compound mercaptan, or sulphide of ethyl 
 and hydrogen : 
 
 5(C 2 H 5 .H.O) + P 2 S 5 = 5(C 2 H 5 .H.S) + P 2 5 . 
 
 These last two reactions illustrate in a striking manner, the difference between mon- 
 atomic and diatomic elements or radicles. In the former, the single atom of oxygen 
 in alcohol is replaced by two atoms of chlorine, one of which unites with the ethyl, 
 and the other with the hydrogen of the alcohol, forming two perfectly distinct chlorides; 
 whereas in the latter, the oxygen of the alcohol is replaced by 1 atom of the diatomic 
 element, sulphur, which being indivisible, binds together the ethyl and hydrogen 
 into one single molecule of mercaptan. (Compare page 11.) 
 
 19. The bromides and iodides of phosphorus, hydrogen, and the metals, act like the 
 chlorides. Hydrofluoric acid appears to convert alcohol into fluoride of ethyl. 
 
 20. Potassium and sodium rapidly decompose absolute alcohol, 1 atom of hydrogen 
 being evolved and its place supplied by the metal ; the resulting compound is an ethyl- 
 ate of potassium (C 2 H 5 KO) or ethylate of sodium, which crystallises from the saturated 
 solution. The same compound appears to be formed by dissolving hydrate of potassium 
 or sodium in absolute alcohol: 
 
 C 2 H 5 .H.O + KHO = C 2 H 5 .K.O + H 2 
 
 The solution thus obtained exhibits in many cases the same reactions as that which is 
 produced by dissolving the metal in alcohol. 
 
 21. Alcohol heated with hydrate of potassium (or sodium) yields hydrogen gas and 
 an acetate : 
 
 C 2 H 6 + KHO = C'H 3 K0 2 + 4H. 
 
 To produce this decomposition, a mixture of equal weights of the alkaline hydrate and 
 pounded quick lime is moistened with alcohol, the excess of alcohol driven off at 100, 
 and the mixture gently heated without access of air. Hydrogen is then evolved, 
 together with a small quantity of marsh gas, and the residue contains acetate of potas- 
 sium, which, at a higher temperature, is resolved into marsh gas and carbonate of 
 potassium (p. 17). 
 
 22. Alcohol-vapour passed over anhydrous baryta heated nearly to redness, yields 
 olefiant gas, marsh gas and hydrogen, with a residue of carbonate of barium. 
 
 23. Gaseous Chloride of cyanogen is readily absorbed by alcohol, but does not decom- 
 pose it immediately. After a few days however, or more quickly if a little water is 
 present or if the liquid is heated to 80, chloride of ammonium separates out, while 
 chloride of ethyl, carbamate of ethyl (urethane) and carbonate of ethyl remain in solu- 
 tion. The urethane and carbonate of ethyl are formed in the manner represented by 
 the two following equations : 
 
 C 2 H 6 4- CNC1 + H 2 = C'ETCO 2 + HC1 
 
 2C 2 H 6 + CNC1 + H 2 = C0 3 (C 2 H 52 + NH 4 C1 
 
 The chloride of ethyl results from the action of the hydrochloric acid, produced as in 
 the first equation, on the alcohol. (Wurtz. Ann. Ch. Pharm. Ixxix. 77.) 
 
 24. Many organic acids when heated with alcohol convert it into compound ethers, 
 with elimination of 1, 2, or 3 atoms of water, according as the acid is monobasic 
 dibasic, or tribasic : e. g. 
 
 C 2 H 5 .H.O + C 2 H 3 O.H.O = C 2 H 3 O.C 2 H 5 .0 + H 2 
 
 Alcohol. Acetic acid. Acetic ether. 
 
 2(C 2 H 5 .H.O) + C0 2 .H 2 .0 2 = C0 2 (C 2 H 5 ) 2 2 + 2H 2 
 
 Alcohol. Oxalic acid. Oxalic ether. 
 
 3(C 2 H S .H.O) + C 6 H0 4 .H 3 .0 S = C 6 H 5 4 .(C 2 H 5 ) 8 .0 3 + 3H 2 
 
 Alcohol. Citric acid. Citric ether. 
 
 "With some acids, e. g. acetic and butyric acids, the transformation is easily effected ; 
 with others, as oxalic and hippuric acid, it takes a considerable time : in other cases 
 again, as with benzoic acid, no ether is formed when the acid and the alcohol are merely 
 
80 ALCOHOL ATES ALCOHOLOMETRY 
 
 distilled together; but on passing hydrochloric gas into the alcoholic solution of the 
 acid, the ether is quickly formed. In this case, chloride of ethyl is first formed and 
 afterwards decomposed by the organic acid. Other strong mineral acids, such as sul- 
 phuric acid, also facilitate the formation of these compound ethers. 
 
 Many polybasic organic acids form acid ethers when digested with alcohol ; thus 
 tartaric acid forms ethyl-tartaric acid C'H G 4 (C 2 H 5 .H)0 2 . 
 
 The anhydrides of monobasic acids quickly convert alcohol into the corresponding 
 ethers. (See Dictionary of Arts, Manufactures, and Mines.) 
 
 Compounds of Alcohol. Alcohol has a very strong affinity for water, and mixes 
 with it in all proportions. The mixture is attended with slight evolution of heat, and 
 also with contraction of volume, which gradually increases till the mixture contains 
 116 pts. water to 100 pts. alcohol. Strong alcohol absorbs moisture from the air. It 
 abstracts water from the moist parts of the animal body, and coagulates them if they 
 are of albuminous nature ; hence its iise in the preservation of anatomical preparations. 
 From the same cause it destroys life in the veins. 
 
 Alcohol dissolves iodine and bromine ; also sulphur and phosphorus in small quan- 
 tities. Gases for the most part dissolve in alcohol more readily than in water. (See 
 GASES, ABSORPTION OF.) Salts are, generally speaking, less soluble in alcohol than in 
 water ; indeed many salts quite insoluble in alcohol are easily soluble in water ; e. g. 
 the alkaline carbonates and sulphates. Chloride of mercury is, however, an exception 
 to the general rule, being more soluble in alcohol than in wafer. Inorganic compoimds, 
 sparingly soluble in water, are, for the most part, quite insoluble in alcohol ; so likewise 
 are efflorescent compounds. But all deliquescent salts, excepting carbonate and phos- 
 phate of potassium and a few others, are soluble in alcohol. 
 
 Since alcohol does not dissolve all compounds which are soluble in water, it follows 
 that many substances, when dissolved in alcohol, do not exhibit the same reactions 
 towards other substances as when dissolved in water. Thus many acids, when dis- 
 solved in absolute alcohol do not redden litmus or decompose carbonate of barium or 
 calcium, probably because the resulting calcium or barium salt would be insoluble in 
 alcohol. 
 
 Alcohol readily dissolves resins, ethers, essential oils, fats, alkaloids, many organic 
 acids, and in general, all substances containing a larger proportion of hydrogen. 
 
 ALCOHOIATES. Alcohol unites in definite proportion with several salts, forming 
 crystallisable compounds, which however have but little stability and are almost all 
 decomposed by water. These compounds were first obtained by Graham. (Graham, 
 Phil. Mag. Ann. iv. 265. 331; Einbrodt, Ann. Ch. Pharm. Ixv. 115; Chodnew, 
 ibid. Ixxi. 241; Lewy, Compt. rend. xxi. 371; Eobiquet, J. Pharm. [3] xxvi. 
 161.) 
 
 Nitrate of magnesium dissolved in alcohol forms, on cooling from a boiling hot solu- 
 tion, a crystalline mass like margarin, containing 3C 2 H 6 O.N0 3 Mg. 
 
 Fused chloride of calcium dissolves in absolute alcohol, and the solution if surrounded 
 with ice, deposits crystals containing 2C 2 H 6 O.CaCl. This compound subjected to dry- 
 distillation yields nothing but carburetted hydrogen. If the alcohol contains a small 
 quantity (about 1 per cent.) of water, the solution yields by evaporation sometimes a 
 crystalline mass, sometimes a syrup, which dries up in vacuo to a white amorphous 
 mass. Both the crystals and the syrup contain 2C 2 H 6 0.3CaCl + H 2 0. 
 
 Chloride of zinc forms with absolute alcohol a crystalline compound which contains 
 C 2 H 6 O.ZnCl, and yields when heated, alcohol, chloride of ethyl, hydrochloric acid and 
 oxide of zinc, but no ether. 
 
 Dichloride of tin and absolute alcohol, brought together in a vessel immersed in a 
 freezing mixture, unite immediately, and on evaporating the solution in vacuo, over 
 sulphuric acid and sticks of potash, crystals are formed containing 4C 2 H G O.Sn 2 Cl 6 0. 
 The crystals are very soluble in alcohol. They distil at 80 almost without decompo- 
 sition (Lewy.) By cooling a mixture of 11*5 pts. of anhydrous alcohol, and 32*4 pts. 
 of dichloride of tin in a frigorific mixture, Robiquet obtained a white powder which, 
 when dissolved in alcohol, yielded by evaporation in vacuo over sulphuric acid, crystals 
 containing 2C 2 H 6 O.SnCl 4 . 
 
 With baryta, alcohol forms the compound 2C 2 H 6 O.Ba 2 0. which is obtained by add- 
 ing anhydrous baryta to absolute alcohol, filtering, and again adding baryta. If the 
 alcoholic solution be then boiled, the compound separates in the form of a granular 
 precipitate which redissolves on cooling. Water added to the solution throws down 
 hydrate of barium. (Berthelot, Ann. Ch. Phys. [3] xlvi. 222.) 
 
 The following substances also form crystalline compounds with alcohol : sesquichloride 
 of iron, protochloride of iron nitrate of calcium, and protochloride of manganese. 
 (Graham.) 
 
ALCOHOLOMETRY. 
 
 81 
 
 The alcohol in all these compounds may be regarded as analogous to water of crys- 
 tallisation. 
 
 AI.COHOli-3A.SES. This name is frequently applied to the organic bases pro- 
 duced by the substitution of alcohol-radicles for the hydrogen in ammonia ; such, as 
 ethylamine, phenylamine, &c. (See AMINES.) 
 
 AXiCOHOXiOXVIBTRlT. (Alcoometric.} The value of spirituous liquors depends 
 upon the quantity of alcohol which they contain. This may be determined in various 
 ways : viz. by the specific gravity of the mixture, by its boiling-point, by the tension of 
 its vapour, by its rate of expansion, and by estimating the proportion of carbon contained 
 in it by combustion with oxide of copper. But of all these methods, that which depends 
 upon the density is almost always employed for practical purposes, other methods being 
 resorted to only when the mixture of alcohol and water is associated with foreign 
 substances, such as sugar, or colouring matter, or salts, in sufficient quantity to produce 
 a material alteration of the density. 
 
 To determine the amount of alcohol in a spirituous liquor by its density, it is neces- 
 sary to know beforehand the density corresponding to each particular proportion of 
 alcohol and water. If these liquids were capable of mixing without alteration of 
 volume, the specific gravity of each particular mixture might be calculated from the 
 proportions of alcohol and water contained in it, and the known specific gravity of 
 absolute alcohol. This however is not the case, the combination of alcohol and water 
 being attended with a contraction of volume varying in amoiint with the temperature. 
 For this reason the specific gravity of each mixture of alcohol and water must be 
 determined by direct experiment, and the results collected in tables. 
 
 The importance of this object for the purposes of revenue induced the British 
 government to employ Sir Charles Blagden to institute a very extensive and accurate 
 series of experiments on the density of spirit of various degrees of strength. The 
 determinations, which were made by CHlpin under Blagden's direction, were first pub- 
 lished in 1790, afterwards twice repeated to obtain greater accuracy, and published in 
 the Philosophical Transactions for 1794. 
 
 The specific gravity of the mixtures of alcohol and water was determined by accu- 
 rately weighing a quantity of the liquid in a flask having a long narrow neck, and 
 filled with it up to a certain mark, the weight of an equal quantity of distilled water 
 having been previously ascertained. In this manner, the specific gravity of 40 mixtures 
 was determined, each at 15 different temperatures. The standard alcohol used to mix 
 with the water was not absolute, but had a specific gravity of 0*82514; for conve- 
 nience, however, it was supposed to be = 0'825, a corresponding deduction being 
 made from all the numbers in the table. 
 
 TABLE I. Showing the Specific Gravity of various mixtures of Alcohol (of Specific 
 Gravity 82500 at 60 Fahr.) and Water at different Temperatures, the Specific Gra- 
 vity of water at 60 Fahr. being 100000. 
 
 Heat. 
 
 The 
 pure 
 spirit. 
 
 100 
 : rains of 
 spirit to 
 5 gr. of 
 water. 
 
 100 
 gniins o! 
 spirit to 
 10 gr. of 
 water. 
 
 100 
 grains o' 
 spirit to 
 15 gr. of 
 water. 
 
 100 
 grains of 
 spirit to 
 20 gr. of 
 water. 
 
 100 
 grains ot 
 spirit to 
 25 gr. of 
 water. 
 
 100 
 grains of 
 spirit to 
 30 gr. of 
 water. 
 
 100 
 grains of 
 spirit to 
 35 gr. of 
 water. 
 
 100 
 grains of 
 spirit to 
 40 gr. of 
 water. 
 
 100 
 grains of 
 spirit to 
 45 gr. of 
 water. 
 
 100 
 grains of 
 spirit to 
 50 gr. of 
 water. 
 
 30 F. 
 
 83896 
 
 84995 
 
 85957 
 
 86825 
 
 87585 
 
 88282 
 
 88921 
 
 89511 
 
 90054 
 
 90558 
 
 91023 
 
 35 
 
 83672 
 
 84769 
 
 85729 
 
 86587 
 
 87357 
 
 88059 
 
 88701 
 
 89294 
 
 89839 
 
 90345 
 
 90811 
 
 40 
 
 83445 
 
 84539 
 
 85507 
 
 86361 
 
 87184 
 
 87838 
 
 88481 
 
 89073 
 
 89617 
 
 90127 
 
 9059(: 
 
 45 
 
 83214 
 
 84310 
 
 85277 
 
 86131 
 
 86905 
 
 87613 
 
 88255 
 
 88849 
 
 89396 
 
 89909 
 
 90380 
 
 50 
 
 82977 
 
 84076 
 
 85042 
 
 85902 
 
 86676 
 
 87384 
 
 88030 
 
 88626 
 
 89174 
 
 89684 
 
 90160 
 
 55 
 
 82736 
 
 83834 
 
 84802 
 
 85664 
 
 86441 
 
 87150 
 
 87796 
 
 88393 
 
 88945 
 
 89458 
 
 89933 
 
 60 
 
 82500 
 
 83599 
 
 84568 
 
 85430 
 
 86208 
 
 86918 
 
 87569 
 
 88169 
 
 88720 
 
 89232 
 
 89707 
 
 65 
 
 82262 
 
 83362 
 
 84334 
 
 85193 
 
 85976 
 
 86686 
 
 87337 
 
 87938 
 
 88490 
 
 89006 
 
 89479 
 
 70 
 
 82023 
 
 83124 
 
 84092 
 
 84951 
 
 85736 
 
 86451 
 
 87105 
 
 87705 
 
 88254 
 
 88773 
 
 89252 
 
 75 
 
 81780 
 
 82878 
 
 83851 
 
 84710 
 
 85496 
 
 86212 
 
 86864 
 
 87466 
 
 88018 
 
 88538 
 
 89018 
 
 80 
 
 81530 
 
 82631 
 
 83603 
 
 84467 
 
 85248 
 
 85966 
 
 86622 
 
 87228 
 
 87776 
 
 88301 
 
 88781 
 
 85 
 
 81291 
 
 82396 
 
 83371 
 
 84243 
 
 85036 
 
 85757 
 
 86411 
 
 87021 
 
 87590 
 
 88120 
 
 88609 
 
 90 
 
 81044 
 
 82150 
 
 83126 
 
 84001 
 
 84797 
 
 85518 
 
 86172 
 
 86787 
 
 87360 
 
 87889 
 
 88376 
 
 95 
 
 80794 
 
 81900 
 
 82877 
 
 83753 
 
 84550 
 
 85272 
 
 85928 
 
 86542 
 
 87114 
 
 87654 
 
 88146 
 
 100 
 
 80548 
 
 81657 
 
 82639 
 
 83513 
 
 84038 
 
 85031 
 
 85688 
 
 86302 
 
 86879 
 
 87421 
 
 87915 
 
 VOL. I. 
 
ALCOHOLOMETRY. 
 
 TABLE I. (continued}. 
 
 
 100 
 
 100 
 
 100 
 
 100 
 
 100 
 
 100 
 
 100 
 
 100 
 
 100 
 
 100 
 
 Bert 
 
 grains of 
 spirit to 
 
 grains of 
 spirit to 
 
 grains of 
 spirit to 
 
 grains of 
 spirit to 
 
 grains of grains of 
 spirit to spirit to 
 
 grains of 
 spirit to 
 
 grains of 
 spirit to 
 
 grains of 
 spirit to 
 
 grains of 
 spirit to 
 
 
 55 gr. of 
 
 60 gr. of 
 
 65 gr. of 
 
 70 gr. of 
 
 75 gr. of , 80 gr. of 
 
 85 gr. of 
 
 90 gr. of 
 
 95 gr. of 
 
 100 gr. of 
 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 30 D F. 
 
 91449 
 
 91847 
 
 92217 
 
 92563 
 
 92889 
 
 93191 
 
 93474 
 
 93741 
 
 93991 
 
 94222 
 
 35 
 
 91241 
 
 91640 
 
 92009 
 
 92355 
 
 92680 
 
 92986 
 
 93274 
 
 93541 
 
 93790 
 
 94025 
 
 40 
 
 91026 
 
 91428 
 
 91799 
 
 92151 
 
 92476 
 
 92783 
 
 93072 
 
 93341 
 
 93592 
 
 93827 
 
 45 
 
 90812 
 
 91211 
 
 91584 
 
 91937 
 
 92264 
 
 92570 
 
 92859 
 
 93131 
 
 93382 
 
 93621 
 
 50 
 
 S0596 
 
 90997 
 
 91370 
 
 91723 
 
 92051 
 
 92358 
 
 92647 
 
 92919 
 
 93177 
 
 93419 
 
 55 
 
 90367 
 
 90768 
 
 91144 
 
 91502 
 
 91837 
 
 92145 
 
 92436 
 
 92707 
 
 92963 
 
 93208 
 
 60 
 
 90144 
 
 90549 
 
 90927 
 
 91287 
 
 91622 
 
 91933 
 
 92225 
 
 92499 
 
 92758 
 
 93002 
 
 65 
 
 89920 
 
 90328 
 
 90707 
 
 91066 
 
 91400 
 
 91715 
 
 92010 
 
 92283 
 
 92546 
 
 92794 
 
 70 
 
 89695 
 
 90104 
 
 90484 
 
 90847 
 
 91181 
 
 91493 
 
 91793 
 
 92069 
 
 92333 
 
 92580 
 
 75 
 
 89464 
 
 89872 
 
 90252 
 
 90617 
 
 90952 
 
 91270 
 
 91569 
 
 91849 
 
 92111 
 
 92364 
 
 80 
 
 89225 
 
 89639 
 
 90021 
 
 90385 
 
 90723 
 
 91046 
 
 91340 
 
 91622 
 
 91891 
 
 92142 
 
 85 
 
 89043 
 
 89460 
 
 89843 
 
 90209 
 
 90558 
 
 90882 
 
 91186 
 
 91465 
 
 91729 
 
 91969 
 
 90 
 
 88817 
 
 89230 
 
 89617 
 
 89988 
 
 90342 
 
 90668 
 
 90967 
 
 91248 
 
 91511 
 
 91751 
 
 95 
 
 88588 
 
 89003 
 
 89390 
 
 89763 
 
 90119 
 
 90443 
 
 90747 
 
 91029 
 
 91290 
 
 91-531 
 
 100 
 
 88357 
 
 88769 
 
 89158 
 
 89536 
 
 89889 
 
 90215 
 
 90522 
 
 90805 
 
 91066 
 
 91310 
 
 
 95 
 
 90 
 
 85 
 
 80 
 
 75 
 
 70 
 
 65 
 
 60 
 
 55 
 
 50 
 
 
 grains of 
 
 grains of 
 
 grains of 
 
 grains of 
 
 grains of 
 
 grains of 
 
 grains of 
 
 grains of 
 
 grains of 
 
 grains of 
 
 Heat. 
 
 spirit to 
 100 gr. of 
 
 spirit to 
 100 gr. of 
 
 spirit to 
 lOOgr. of 
 
 spirit to 
 lOOgr.of 
 
 spirit to 
 lOOgr. of 
 
 spirit to 
 lOOgr.of 
 
 spirit to 
 100 gr. of 
 
 spirit to 
 100 gr. of 
 
 spirit to 
 lOOgr.of 
 
 spirit to 
 100 gr.of 
 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 w att-r. 
 
 30 F. 
 
 94447 
 
 94675 
 
 94920 
 
 95173 
 
 95429 
 
 95681 
 
 95944 
 
 96209 
 
 96470 
 
 96719 
 
 35 
 
 94249 
 
 94484 
 
 94734 
 
 94988 
 
 95246 
 
 95502 
 
 95772 
 
 96048 
 
 96315 
 
 96579 
 
 40 
 
 94058 
 
 94295 
 
 94547 
 
 94802 
 
 95060 
 
 95328 
 
 95602 
 
 95879 
 
 96159 
 
 96434 
 
 45 
 
 93860 
 
 94096 
 
 94348 
 
 94605 
 
 94871 
 
 95143 
 
 95423 
 
 95703 
 
 95993 
 
 96280 
 
 50 
 
 93658 
 
 93897 
 
 94149 
 
 94414 
 
 94683 
 
 94958 
 
 95243 
 
 95534 
 
 95831 
 
 96126 
 
 55 
 
 93452 
 
 93696 
 
 93948 
 
 94213 
 
 94486 
 
 94767 
 
 95057 
 
 95357 
 
 95662 
 
 95966 
 
 60 
 
 93247 
 
 93493 
 
 93749 
 
 94018 
 
 94296 
 
 94579 
 
 94876 
 
 95181 
 
 95493 
 
 95804 
 
 65 
 
 93040 
 
 93285 
 
 93546 
 
 93822 
 
 94099 
 
 94388 
 
 94689 
 
 95000 
 
 95318 
 
 95635 
 
 70 
 
 92829 
 
 93076 
 
 93337 
 
 93616 
 
 93898 
 
 94193 
 
 94500 
 
 94813 
 
 95139 
 
 95469 
 
 75 
 
 92613 
 
 92865 
 
 93132 
 
 93413 
 
 93695 
 
 93989 
 
 94301 
 
 94623 
 
 94957 
 
 95292 
 
 80 
 
 92393 
 
 92646 
 
 92917 
 
 93201 
 
 93488 
 
 93785 
 
 94102 
 
 94431 
 
 94768 
 
 95111 
 
 
 45 
 
 40 
 
 35 
 
 30 
 
 25 
 
 20 
 
 15 
 
 10 
 
 5 
 
 
 grains of 
 
 grains of 
 
 grains of 
 
 grains of 
 
 grains of 
 
 grains of 
 
 grains of 
 
 grains of 
 
 grains of 
 
 Heat. 
 
 spirit to 
 
 spirit to 
 
 spirit to 
 
 spirit to 
 
 spirit to 
 
 spirit to 
 
 spirit to 
 
 spirit to 
 
 spirit to 
 
 
 100 gr. of 
 
 100 sr. of 
 
 lOOgr.of 
 
 100 gr. of 
 
 lOOgr.of 
 
 100 gr. of 
 
 lOOgr.of 
 
 lOOgr.of 
 
 ICOgr.of 
 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 water. 
 
 30 F. 
 
 96967 
 
 97200 
 
 97418 
 
 97635 
 
 97860 
 
 98108 
 
 98412 
 
 98814 
 
 99334 
 
 35 
 
 96840 
 
 97086 
 
 97319 
 
 97556 
 
 97801 
 
 98076 
 
 98397 
 
 98804 
 
 99344 
 
 40 
 
 96706 
 
 96967 
 
 97220 
 
 97472 
 
 97737 
 
 98033 
 
 98373 
 
 98795 
 
 99345 
 
 45 
 
 96563 
 
 96840 
 
 97110 
 
 97384 
 
 97666 
 
 97980 
 
 98338 
 
 98774 
 
 99338 
 
 50 
 
 96420 
 
 96708 
 
 96995 
 
 97284 
 
 97589 
 
 97920 
 
 98293 
 
 98745 
 
 99316 
 
 55 
 
 96272 
 
 96575 
 
 96877 
 
 97181 
 
 97500 
 
 97847 
 
 98239 
 
 98702 
 
 99284 
 
 60 
 
 96122 
 
 96437 
 
 96752 
 
 97074 
 
 97410 
 
 97771 
 
 98176 
 
 98654 
 
 99244 
 
 65 
 
 95962 
 
 96288 
 
 96620 
 
 96959 
 
 97309 
 
 97688 
 
 98106 
 
 98594 
 
 991<?4 
 
 70 
 
 95802 
 
 96143 
 
 96484 
 
 96836 
 
 97203 
 
 97596 
 
 98028 
 
 98527 
 
 991?4 
 
 75 
 
 95638 
 
 95987 
 
 96344 
 
 96708 
 
 97086 
 
 97495 
 
 97943 
 
 98454 
 
 99G66 
 
 80 
 
 95467 
 
 95826 
 
 96192 
 
 96568 
 
 96963 
 
 97385 
 
 97845 
 
 98367 
 
 98991 
 
ALCOHOLOMETRY. 83 
 
 Gilpin's tables do not give directly the quantity of absolute alcohol contained in spirit 
 of any given density. In this respect, however, they have been completed by the 
 experiments of Tralles, who in 1811 (Gilbert's Annalen, xxxviii. 386), determined 
 the specific gravity of alcohol, dehydrated as completely as possible by means of 
 chloride of calcium, and likewise the strength of Gilpin's standard spirit, having a 
 specific gravity of 0*825 at 60 F. He found that the specific gravity of absolute 
 alcohol at 60 F. compared with that of water at its maximum density is 0*7939 (or 
 0*7946 compared with water at 60) and that Gilpin's standard spirit contains in 100 
 parts by weight, 89 -2 parts of anhydrous alcohol, and 10 '8 parts of water. Proceeding 
 upon these data, Tralles calculated the proportions of absolute alcohol and water con- 
 tained in spirit of various densities ; the results are given in Table II. p. 83. 
 
 The proportions of alcohol in spirit of wine may be expressed either by weight or by 
 volume. The former mode of expression is by far the simpler and more definite, 
 because the proportion by weight is independent of the temperature, whereas the 
 proportion by volume varies with the temperature, being affected by the different 
 rates of expansion of alcohol and water. For scientific purposes, therefore, the 
 strength of spirit is always expressed in percentage by weight. In commerce, 
 on the contrary, the method by volume is always adopted, spirit being generally 
 bought and sold by measure, not by weight. It becomes therefore necessary to know 
 how to calculate the composition by volume from the composition by weight and the 
 observed specific gravity. 
 
 Let 8 be the specific gravity of the spirit (mixture of alcohol and water) : a the 
 quantity of alcohol in 100 parts by weight, and therefore 100 a the quantity of 
 water ; V the volume of the spirit referred to a unit of volume, such that a quantity 
 of water which fills it is the unit of weight (e, g. if the weight is expressed in grammes, 
 V is measured in cubic centimetres) then : 
 
 100 = V . S 
 
 If then, the specific gravity of anhydrous alcohol at the observed temperature com- 
 pared with water at the same temperature be s, the volumes of alcohol and water con- 
 tained in the spirit are : 
 
 and 100 a 
 d consequently, the proportions of alcohol and water in 100 volumes of the spirit 
 
 an 
 
 a 100 8 . . . , . 
 
 - . -=- = a. volumes of alcohol. 
 s V s 
 
 and: (100 -a) = (100 - a) S volumes of water. 
 
 For example : from the table p. 85 it appears that spirit containing 77*09 per cent, of 
 alcohol by weight has at 60 F. a sp. gr. of 0-8555, referred to water at the same tem- 
 perature, and the specific gravity of absolute alcohol referred to the same standard is 
 07946 : hence the percentage of alcohol by volume is : 
 
 77-09 = 83-00 
 
 and the percentage by volume of water is : 
 
 (100 77-09) . 0-8555 = 22-91 . 0*8555 = 20-60 
 the whole being measured at 60 F. 
 
 The volumes of alcohol and water thus obtained amount together to more than 100, 
 in the preceding example to 103*60 ; and accordingly, if 83'00. measures of alcohol be 
 mixed with 20-60 measures of water, both at 60 F., the mixture, after it has cooled to 
 60 F., will fill exactly 100 measures, and the spirit thus produced will contain 
 83 volumes per cent, of alcohol. (Eespecting the contraction which takes place on 
 mixing alcohol and water in various proportions, see Eudberg, Pogg. Ann. xiii. 196 ; 
 also Kopp, ibid. liii. 356.) 
 
 When the volume per cent, in a mixture of alcohol and water is given, the weight 
 per cent, is found from the equation : 
 
 Thus, according to the table (p. 85) spirit containing 68 volumes per cent, of alcohol 
 has a sp. gr. of 0*8949 at 60 F. Hence the weight per cent, of alcohol is: 
 
 6 ' 38 
 
 that is to say : 100 Ibs. of this spirit contain 69-38 Ibs. of alcohol and 39 -62 Ibs. of water. 
 
 G 2 
 
84 
 
 ALCOHOLOMETRY. 
 
 The specific gravity of aqueous alcohol may be determined by any of the ordinary 
 methods ; either by weighing in a specific gravity bottle, or by means of the hydrometer 
 (See SPECIFIC GRAVITY and HYDROMETER) and thence the percentage of anhydrous 
 alcohol by weight and by volume may be determined by means of the preceding formulae 
 and the tables to be given hereafter. To facilitate these determinations, hydrometers 
 are constructed with scales marking directly the percentage of alcohol by volume, and 
 sometimes also by weight, of the spirit in which they are immersed. Such instru- 
 ments are called ALCOHOLOMETERS. Three of them are in use, viz. the alcoholometer 
 of Tralles, which gives the percentage volume for the temperature of 60 F. 
 = 12| R. = 15| C. ; Gay-Lussac's alcoholometer, which likewise indicates percentage 
 by volume at 15 C. ; and Meissner's, which gives percentages both by weight 
 and volume, the latter for the temperature of 14 K = 17 '5 C. 
 
 As the scales of these instruments are constructed for different temperatures, they 
 cannot be expected to agree exactly ; but the differences arising from this cause are 
 trifling. Greater discrepancies however arise from the different experimental data 
 upon which the scales have been constructed ; that of Tralles being founded on the 
 exact and extensive observations of Gilpin, and Meissner's on experiments of his own. 
 Gay-Lussac has not stated on what experimental data his observations are founded, 
 but his numbers agree very nearly with those of Tralles, the differences never exceed- 
 ing per cent, for the same specific gravity. 
 
 The following table gives the percentages of anhydrous alcohol both by weight and 
 volume of mixtures of alcohol and water, according to their specific gravity as determined 
 by Tralles from the observations of Gilpin ; also the specific gravities as determined by 
 Gay-Lussac. They are deduced from Tralles' numbers by multiplying by 1*0009. 
 The corresponding indications of the hydrometers of Beck, Baum6, and Cartier, are 
 likewise added. 
 
 TABLE II. 
 
 Volumes 
 per cent, 
 accord- 
 ing to 
 Tralles. 
 
 Weights per cent. 
 
 Specific gravities 
 according to Gilpin 
 at60F. = 15f C. 
 
 Specific gravities 
 according to Gay- 
 Lussac at 15 C. 
 
 Degrees of 
 Beck's Hy- 
 drometer. 
 
 Degrees of 
 Baume's 
 Hydro- 
 meter. 
 
 Degrees of 
 Cartier's 
 Hydro- 
 meter. 
 
 
 
 
 
 1-0000 
 
 1-0000 
 
 o-o 
 
 10 
 
 11 
 
 1 
 
 0-80 
 
 0-9985 
 
 
 
 
 
 
 
 
 
 2 
 
 1-60 
 
 9970 
 
 
 
 
 
 
 
 
 
 3 
 
 2-40 
 
 9956 
 
 
 
 
 
 
 
 
 
 4 
 
 3-20 
 
 9942 
 
 
 
 1-0 
 
 
 
 
 
 5 
 
 4-00 
 
 9928 
 
 
 
 1-2 
 
 11 
 
 12 
 
 6 
 
 4-81 
 
 9915 
 
 
 
 1-4 
 
 
 
 
 
 7 
 
 5-62 
 
 9902 
 
 
 
 1-6 
 
 
 
 
 
 8 
 
 6-43 
 
 9890 
 
 
 
 1-9 
 
 
 
 
 
 9 
 
 7-24 
 
 9878 
 
 
 
 2-1 
 
 
 
 
 
 10 
 
 8-05 
 
 9866 
 
 
 
 2-3 
 
 12 
 
 
 
 11 
 
 8-87 
 
 9854 
 
 
 
 2-5 
 
 
 
 
 
 12 
 
 9-69 
 
 9844 
 
 
 
 2-7 
 
 
 
 13 
 
 13 
 
 10-51 
 
 9832 
 
 
 
 2-9 
 
 _ 
 
 
 
 14 
 
 11-33 
 
 9821 
 
 
 
 3-1 
 
 
 
 
 
 15 
 
 12-15 
 
 9811 
 
 
 
 3-3 
 
 
 
 
 
 16 
 
 12-98 
 
 9800 
 
 
 
 3-5 
 
 13 
 
 
 
 17 
 
 13-80 
 
 9790 
 
 
 
 3-6 
 
 
 
 
 
 18 
 
 14-63 
 
 9780 
 
 
 
 3-8 
 
 
 
 
 
 19 
 
 15-46 
 
 9770 
 
 
 
 4-0 
 
 
 
 14 
 
 20 
 
 16-28 
 
 9760 
 
 
 
 4-2 
 
 
 
 _ 
 
 21 
 
 17-11 
 
 9750 
 
 
 
 4-4 
 
 
 
 
 
 22 
 
 17-95 
 
 9740 
 
 
 
 4-6 
 
 
 
 
 
 23 
 
 18-78 
 
 9729 
 
 
 
 4-8 
 
 14 
 
 
 
 24 
 
 19-62 
 
 9719 
 
 
 
 4-9 
 
 
 
 
 
 25 
 
 20-46 
 
 9709 
 
 
 
 5-1 
 
 
 
 
 
 26 
 
 21-30 
 
 9698 
 
 
 
 5-3 
 
 
 
 15 
 
 27 
 
 22-14 
 
 9688 
 
 
 
 5-5 
 
 
 
 
 
 28 
 
 22-99 
 
 9677 
 
 
 
 5-7 
 
 
 
 
 
 29 
 
 23-84 
 
 9666 
 
 
 
 5-9 
 
 15 
 
 
 
 30 
 
 24-69 
 
 9655 
 
 0-9656 
 
 6-1 
 
 
 
 
 
 31 
 
 25-55 
 
 9643 
 
 
 
 6-4 
 
 
 
 , 
 
 32 
 
 26-41 
 
 9631 
 
 
 
 6-6 
 
 
 
 
 
ALCOHOLOMETRY. 
 
 TABLE II. (continued}. 
 
 Volumes 
 per cent, 
 accoi d - 
 ing to 
 Tralles. 
 
 Weights per cent. 
 
 Specific Gravities 
 according to Gflpin 
 at 60 F.=15 C. 
 
 Specific Gravities 
 according to Gay- 
 Lussac at 15 C. 
 
 Degrees of 
 Back's 
 Hydro- 
 meter. 
 
 Degrees of 
 Cat-tier's 
 Hydro- 
 meter. 
 
 Degrees of 
 Baume's 
 Hydro- 
 meter. 
 
 33 
 
 27-27 
 
 0-9618 
 
 0-9656 
 
 6-8 
 
 15 
 
 16 
 
 34 
 
 28-13 
 
 9605 
 
 
 
 7-0 
 
 16 
 
 
 
 35 
 
 28-99 
 
 9592 
 
 9595 
 
 7-2 
 
 
 
 
 
 36 
 
 29-86 
 
 9579 
 
 
 
 7-5 
 
 
 
 
 
 37 
 
 30-74 
 
 9565 
 
 
 
 77 
 
 
 
 
 
 38 
 
 31-62 
 
 9550 
 
 
 
 8-0 
 
 
 
 17 
 
 39 
 
 32-50 
 
 9535 
 
 
 
 8-3 
 
 17 
 
 
 
 40 
 
 33-39 
 
 9519 
 
 9523 
 
 8-6 
 
 
 
 _ 
 
 41 
 
 34-28 
 
 9503 
 
 
 
 8-0 
 
 
 
 
 
 42 
 
 35-18 
 
 9487 
 
 
 
 9-2 
 
 
 
 18 
 
 43 
 
 36-08 
 
 9470 
 
 
 
 9-5 
 
 18 
 
 
 
 44 
 
 36-99 
 
 9452 
 
 
 
 9-8 
 
 
 
 
 
 45 
 
 37-90 
 
 9435 
 
 9440 
 
 10-2 
 
 
 
 
 
 46 
 
 38-82 
 
 9417 
 
 
 
 10-5 
 
 19 
 
 19 
 
 47 
 
 39-75 
 
 9399 
 
 __ 
 
 10-9 
 
 
 
 
 
 48 
 
 40-66 
 
 9381 
 
 
 
 11-2 
 
 
 
 
 
 49 
 
 41-59 
 
 9362 
 
 
 
 11-6 
 
 
 
 
 
 50 
 
 42-52 
 
 9343 
 
 9348 
 
 11-9 
 
 20 
 
 20 
 
 51 
 
 43-47 
 
 9323 
 
 
 
 12-3 
 
 
 
 
 
 52 
 
 44-42 
 
 9303 
 
 
 
 12-7 
 
 
 
 
 
 53 
 
 45-36 
 
 9283 
 
 
 
 13-1 
 
 21 
 
 
 
 54 
 
 46-32 
 
 9262 
 
 
 
 13-5 
 
 
 
 21 
 
 55 
 
 47-29 
 
 9242 
 
 9248 
 
 13-9 
 
 
 
 
 56 
 
 48-26 
 
 9221 
 
 
 
 14-3 
 
 22 
 
 
 
 57 
 
 49-23 
 
 9200 
 
 
 
 14-8 
 
 
 22 
 
 58 
 
 50-21 
 
 9178 
 
 
 
 15-2 
 
 23 
 
 
 59 
 
 51-20 
 
 9156 
 
 
 
 15-6 
 
 
 
 
 60 
 
 52-20 
 
 9134 
 
 9141 
 
 16-1 
 
 
 23 
 
 61 
 
 53-20 
 
 9112 
 
 
 
 16-5 
 
 24 
 
 
 62 
 
 54-21 
 
 9090 
 
 
 
 17-0 
 
 
 
 
 63 
 
 55-21 
 
 9067 
 
 
 
 17-5 
 
 25 
 
 24 
 
 64 
 
 56-22 
 
 9044 
 
 
 
 18-0 
 
 
 
 65 
 
 57-24 
 
 9021 
 
 9027 
 
 18-4 
 
 
 
 25 
 
 66 
 
 59-27 
 
 8997 
 
 
 
 18-9 
 
 26 
 
 
 67 
 
 59-32 
 
 8973 
 
 __ 
 
 19-4 
 
 
 
 
 68 
 
 60-38 
 
 8949 
 
 
 
 20-0 
 
 27 
 
 26 
 
 69 
 
 61-42 
 
 8925 
 
 
 
 20-5 
 
 
 
 70 
 
 62-50 
 
 8900 
 
 8907 
 
 21-0 
 
 28 
 
 27 
 
 71 
 
 63-58 
 
 8875 
 
 ___ 
 
 21-5 
 
 
 
 72 
 
 64-66 
 
 8850 
 
 
 
 22-1 
 
 
 
 
 
 73 
 
 65-74 
 
 8824 
 
 
 
 22-6 
 
 29 
 
 28 
 
 74 
 
 66-83 
 
 8799 
 
 
 
 23-2 
 
 
 
 75 
 
 67-93 
 
 8773 
 
 8799 
 
 23-8 
 
 30 
 
 29 
 
 76 
 
 69-05 
 
 8747 
 
 
 
 24-4 
 
 
 
 77 
 
 70-18 
 
 8720 
 
 
 
 25-0 
 
 31 
 
 30 
 
 78 
 
 71-31 
 
 8693 
 
 
 
 25-6 
 
 
 
 79 
 
 72-45 
 
 8664 
 
 
 
 26-2 
 
 32 
 
 
 
 80 
 
 73-59 
 
 8639 
 
 8645 
 
 26-8 
 
 
 31 
 
 81 
 
 74-74 
 
 8611 
 
 
 27-4 
 
 33 
 
 
 82 
 
 75-91 
 
 8583 
 
 _ 
 
 28-0 
 
 34 
 
 32 
 
 83 
 
 77-09 
 
 8555 
 
 
 
 287 
 
 
 
 84 
 
 78-29 
 
 8526 
 
 
 
 29-4 
 
 35 
 
 33 
 
 85 
 
 79-50 
 
 8496 
 
 8502 
 
 30-1 
 
 
 
 86 
 
 8071 
 
 8466 
 
 
 30-8 
 
 36 
 
 34 
 
 o 3 
 
86 
 
 ALCOIIOLOMETRY. 
 
 TABLE II. (continued}. 
 
 Volumes 
 per cent, 
 accord- 
 ing to 
 Tralles. 
 
 Weights per cent. 
 
 Specific Gravities 
 according to Gil- 
 pin atGO=155C. 
 
 Specific Gravities 
 according to Gay- 
 Lussac at 15 C. 
 
 Degrees of 
 Be<k's Hy- 
 drometer 
 
 Degrees of 
 Baume's 
 Hydro- 
 meter. 
 
 Degrees of 
 Cartier's 
 Hydro- 
 meter. 
 
 87 
 
 81-94 
 
 0-8436 
 
 0-8502 
 
 31-5 
 
 37 
 
 35 
 
 88 
 
 83-19 
 
 8405 
 
 
 
 32-2 
 
 
 
 
 
 89 
 
 84-46 
 
 8373 
 
 
 
 33-0 
 
 38 
 
 36 
 
 90 
 
 85-75 
 
 8340 
 
 8346 
 
 33-8 
 
 . 
 
 
 
 91 
 
 87-09 
 
 8306 
 
 
 
 34-7 
 
 39 
 
 37 
 
 92 
 
 88-37 
 
 8272 
 
 
 
 35-5 
 
 40 
 
 38 
 
 93 
 
 89-71 
 
 8237 
 
 
 
 36-4 
 
 41 
 
 
 
 94 
 
 91-07 
 
 8201 
 
 
 
 37*3 
 
 
 
 39 
 
 95 
 
 92-46 
 
 8164 
 
 8168 
 
 38-2 
 
 42 
 
 40 
 
 96 
 
 93-89 
 
 8125 
 
 
 
 39-2 
 
 43 
 
 
 
 97 
 
 95-34 
 
 8084 
 
 
 
 40-3 
 
 44 
 
 41 
 
 98 
 
 96-84 
 
 8041 
 
 
 
 41-5 
 
 45 
 
 42 
 
 99 
 
 98-39 
 
 7995 
 
 
 
 42-7 
 
 46 
 
 43 
 
 100 
 
 100-00 
 
 7946 
 
 7947 
 
 43-9 
 
 47 
 
 
 
 The use of this table may be extended to intermediate numbers by interpolation. 
 Thus, if it be required to find the composition by volume of a mixture of 50 Ibs. of 
 anhydrous alcohol and 50 Ibs. of water, we find from the table that : 
 
 49-23 p. c. by weight corresponds to 57 p. c. by Tolume 
 and: 50- 2 58_ 
 
 difference 0*98 and 1 
 
 Hence, to find the fraction which must be added to the number 57 to give the percent- 
 age required, we have the proportion : 
 
 0-98 : (50 - 49-23) = 1 : x 
 
 which gives : x = - = 0'8 
 
 y o 
 
 Whence it appears that 100 volumes (measured at 60 F.) of a spirit containing equal 
 weights of alcohol and water contain 5 7 "8 volumes of alcohol, also at 60. 
 
 Again, let it be required to find the composition of a spirit having at 60 Fahr. the 
 specific gravity 0'8955, compared with water at the same temperature; this number is 
 intermediate between the numbers 8949 and 8973 in the third column of the table, 
 which correspond to the volume per centages 67 and 68 ; hence the proportion : 
 8973 - 8949 : 8973 - 8955 = 1 : x 
 
 which gives 
 
 18 _ 
 
 ; 2T= * 
 
 that is to say, 100 measures of spirit of sp. 0'8955 at 60 Fahr. contain 67| measures of 
 anhydrous alcohol. 
 
 Meissner's results are given in his " Araometrie in ihrer Anwendung auf Chemie und 
 Technik," Wien, 1816. Th. ii. 27. They differ somewhat from the preceding. 
 
 TABLE II. a. Specific Gravity (according to Meissner) ofHydrated Alcohol containing 
 
 in 100 parts: 
 
 Alcohol. 
 
 By Weight. 
 
 By Volume. 
 
 Parts. 
 
 At 20 C. 
 
 At 17-5 C. 
 
 At 20 C. 
 
 At 17'5 C. 
 
 100 
 
 0-791 
 
 0-793 
 
 0-791 
 
 0-793 
 
 95 
 
 0-805 
 
 0-801 
 
 0-809 
 
 0-811 
 
 90 
 
 0-818 
 
 0-822 
 
 0-824 
 
 0-828 
 
 85 
 
 0-831 
 
 0-835 
 
 0-839 
 
 0-843 
 
 80 
 
 0-843 
 
 0-847 
 
 0-854 
 
 0-857 
 
 75 
 
 0-856 
 
 0-859 
 
 0-867 
 
 0-869 
 
 70 
 
 0-868 
 
 0-870 
 
 0-880 
 
 0-883 
 
ALCOHOLOMETRY. 
 
 87 
 
 TABLE II. a. (continued). 
 
 Alcohol. 
 
 By Weight. 
 
 By Volume. 
 
 Parts. 
 
 At 20 C. 
 
 At 17-5 C. 
 
 At 20 C. 
 
 At 17-5 C. 
 
 65 
 
 0-880 
 
 0-883 
 
 0-893 
 
 0-896 
 
 60 
 
 0-892 
 
 0-895 
 
 0-906 
 
 0-907 
 
 55 
 
 0904 
 
 0-906 
 
 0-917 
 
 0-919 
 
 50 
 
 0-915 
 
 0-917 
 
 0-928 
 
 0-930 
 
 45 
 
 0-926 
 
 0-928 
 
 0-938 
 
 0-940 
 
 40 
 
 0-937 
 
 0-939 
 
 0-947 
 
 0-949 
 
 35 
 
 0-947 
 
 0-948 
 
 0-955 
 
 0-958 
 
 30 
 
 0-955 
 
 0-958 
 
 0-963 
 
 0-964 
 
 25 
 
 0-963 
 
 0-965 
 
 0-969 
 
 0-970 
 
 20 
 
 0-970 
 
 0-971 
 
 0-975 
 
 0-976 
 
 15 
 
 0-977 
 
 0-977 
 
 0-981 
 
 0-980 
 
 10 
 
 0-984 
 
 0-983 
 
 0-987 
 
 0-986 
 
 5 
 
 0-992 
 
 0-991 
 
 0-993 
 
 0-993 
 
 
 
 1-000 
 
 1-000 
 
 1-000 
 
 1-000 
 
 TABLE II. b. The following Table is given by Fownes (Manual of Chemistry, 3rd Ed. 
 p. 591), the Specific Gravities being taken at 15-6 C. or 60 Fahr. 
 
 Percentage 
 by weight. 
 
 Specific Gravity. 
 
 Percentage 
 by weight. 
 
 Specific Gravity. 
 
 Percentage 
 by weight. 
 
 Specific Gravity. 
 
 0-5 
 
 0-9991 
 
 34 
 
 0-9511 
 
 68 
 
 0-8769 
 
 1 
 
 0-9981 
 
 35 
 
 0-9490 
 
 69 
 
 0-8745 
 
 2 
 
 0-9965 
 
 36 
 
 0-9470 
 
 70 
 
 0-8721 
 
 3 
 
 0-9947 
 
 37 
 
 0-9452 
 
 71 
 
 0-8696 
 
 4 
 
 0-9930 
 
 38 
 
 0-9434 
 
 72 
 
 0-8672 
 
 5 
 
 0-9914 
 
 39 
 
 0-9416 
 
 73 
 
 0-8649 
 
 6 
 
 0-9898 
 
 40 
 
 0-9396 
 
 74 
 
 0-8625 
 
 7 
 
 0-9884 
 
 41 
 
 0-9376 
 
 75 
 
 0-8603 
 
 8 
 
 0-9869 
 
 42 
 
 0-9356 
 
 76 
 
 0-8581 
 
 9 
 
 0-9855 
 
 43 
 
 0-9335 
 
 77 
 
 0-8557 
 
 10 
 
 0-9841 
 
 44 
 
 0-9314 
 
 78 
 
 0-8533 
 
 11 
 
 0-9828 
 
 45 
 
 0-9292 
 
 79 
 
 0-8508 
 
 12 
 
 0-9815 
 
 46 
 
 0-9270 
 
 80 
 
 0-8483 
 
 13 
 
 0-9802 
 
 47 
 
 0-9249 
 
 81 
 
 0-8459 
 
 14 
 
 0-9789 
 
 48 
 
 0-9228 
 
 82 
 
 0-8434 
 
 15 
 
 0-9778 
 
 49 
 
 0-9206 
 
 83 
 
 0-8408 
 
 16 
 
 0-9766 
 
 50 
 
 0-9184 
 
 84 
 
 0-8382 
 
 17 
 
 0-9753 
 
 51 
 
 0-9160 
 
 85 
 
 0-8357 
 
 18 
 
 0-9741 
 
 52 
 
 0-9135 
 
 86 
 
 0-8331 
 
 19 
 
 0-9728 
 
 53 
 
 0-9113 
 
 87 
 
 0-8305 
 
 20 
 
 0-9716 
 
 54 
 
 0-9090 
 
 88 
 
 0-8279 
 
 21 
 
 0-9704 
 
 55 
 
 0-9069 
 
 89 
 
 0-8254 
 
 22 
 
 0-9691 
 
 56 
 
 0-9047 
 
 90 
 
 0-8228 
 
 23 
 
 0-9678 
 
 57 
 
 0-9025 
 
 91 
 
 0-8199 
 
 24 
 
 0-9665 
 
 58 
 
 0-9001 
 
 92 
 
 0-8172 
 
 25 
 
 0-9652 
 
 59 
 
 0-8979 
 
 93 
 
 0-8145 
 
 26 
 
 0-9638 
 
 60 
 
 0-8956 
 
 94 
 
 0-8118 
 
 27 
 
 0-9623 
 
 61 
 
 0-8932 
 
 95 
 
 0-8089 
 
 28 
 
 0-9609 
 
 62 
 
 0-8908 
 
 96 
 
 0-8061 
 
 29 
 
 0-9593 
 
 63 
 
 0-8886 
 
 97 
 
 0-8031 
 
 30 
 
 0-9578 
 
 64 
 
 0-8863 
 
 98 
 
 0-8001 
 
 31 
 
 0-9560 
 
 65 
 
 0-8840 
 
 99 
 
 07969 
 
 32 
 
 0-9544 
 
 66 
 
 0-8816 
 
 100 
 
 07938 
 
 33 
 
 0-9528 
 
 67 
 
 0-8793 
 
 
 
 o 4 
 
83 
 
 ALCOHOLOMKTRY. 
 
 It is often necessary to take the specific gravity of spirit at a temperature different 
 from the standard. In that case, the percentage of alcohol may be determined by means 
 of the two following tables, given by Tralles. 
 
 TABLE III. Specific Gravity of Spirit of different strengths at Temperatures from 
 30 Fahr. to 100 Fahr. that of Water at 39*83 Fahr. being = 10000. 
 
 Quantity of 
 Alcohol at 
 
 Temperatures (Fahr.) 
 
 iiO Fahr 
 
 
 
 
 in percent- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 ages by. 
 Volume. 
 
 30. 
 
 35. 
 
 40. 
 
 45. 
 
 50. 
 
 55. 
 
 60. 
 
 65. 
 
 70. 
 
 75. 
 
 80. 
 
 85. 
 
 90. 
 
 95. 
 
 100. 
 
 
 
 9998 
 
 10000 
 
 10000 
 
 0000 
 
 9998 
 
 9995 
 
 9991 
 
 9986 
 
 9980 
 
 9974 
 
 9967 
 
 9959 9951 
 
 9941 
 
 9931 
 
 5 
 
 9923 
 
 9929 
 
 9929 
 
 99-28 
 
 9926 
 
 9923 
 
 9919 
 
 9914 
 
 9908 
 
 9901 
 
 9894 
 
 9816 | 9877 
 
 9868 
 
 9857 
 
 10 
 
 9872 
 
 9872 
 
 9871 
 
 9869 
 
 9866 
 
 986-2 
 
 9857 
 
 9851 
 
 9844 
 
 9837 
 
 9828 
 
 9820 ; 9810 
 
 9800 
 
 97&-.I 
 
 15 
 
 9827 
 
 9825 
 
 9823 
 
 9819 
 
 9814 
 
 9808 
 
 9X02 
 
 9795 
 
 9787 
 
 9777 
 
 9768 
 
 1*758 9747 
 
 9735 
 
 97-23 
 
 20 
 
 9790 
 
 9786 
 
 9780 
 
 9774 
 
 9767 
 
 9759 
 
 9751 
 
 9742 
 
 9732 
 
 9721 
 
 9710 
 
 9698 9685 
 
 9672 
 
 9658 
 
 25 
 
 9756 
 
 9748 
 
 9739 
 
 9731 
 
 9721 
 
 9710 
 
 9700 
 
 9689 
 
 9676 
 
 9664 
 
 9650 
 
 9637 
 
 9622 
 
 9607 
 
 9591 
 
 30 
 
 9719 
 
 9708 
 
 9697 
 
 96S5 
 
 9672 
 
 9659 
 
 9646 
 
 9632 
 
 9618 
 
 9603 
 
 9587 
 
 9571 9555 
 
 9538 
 
 9521 
 
 35 
 
 9672 
 
 9658 
 
 9614 
 
 9629 
 
 9614 
 
 9599 
 
 9583 
 
 9566 
 
 9550 
 
 9583 
 
 9515 
 
 9497 
 
 9479 
 
 9461 
 
 9442 
 
 40 
 
 9613 
 
 95'.7 
 
 9580 
 
 9o62 
 
 9045 
 
 9528 
 
 9510 
 
 9492 
 
 9473 
 
 9454 
 
 9435 
 
 9416 i9396 
 
 9376 
 
 9356 
 
 45 
 
 9539 
 
 9521 
 
 9503 
 
 9484 
 
 9466 
 
 9446 
 
 9427 
 
 9407 
 
 9387 
 
 9367 
 
 9347 
 
 9326 9305 
 
 924 
 
 9263 
 
 50 
 
 9453 
 
 9454 
 
 9415 
 
 9395 
 
 9375 
 
 9355 
 
 9335 
 
 9314 
 
 9293 
 
 9272 
 
 9251 
 
 9229 
 
 9207 
 
 9185 
 
 9162 
 
 55 
 
 9358 
 
 9338 
 
 9318 
 
 9297 
 
 9276 
 
 9255 
 
 9234 
 
 9212 
 
 9191 
 
 9169 
 
 9147 
 
 9125 910-2 
 
 907!) 
 
 9056 
 
 60 
 
 9253 
 
 9233 
 
 9212 
 
 91!.'l 
 
 91<i9 
 
 9148 
 
 9126 
 
 9104 
 
 9082 
 
 9089 
 
 9036 
 
 9013 
 
 8'.)90 
 
 8967 
 
 8943 
 
 65 
 
 9143 
 
 9122 
 
 9101 
 
 9080 
 
 9058 
 
 9035 
 
 9013 
 
 8991 
 
 8968 
 
 8945 
 
 8921 
 
 8898 i 8875 
 
 8851 
 
 88V6 
 
 70 
 
 9025 
 
 0004 
 
 8982 
 
 8960 
 
 8i37 
 
 8914 
 
 8892 
 
 8869 
 
 8846 
 
 8823 
 
 8799 
 
 8775 
 
 8751 
 
 8727 
 
 8702 
 
 75 
 
 8900 
 
 8878 
 
 8856 
 
 8833 
 
 8811 
 
 878S 
 
 8765 
 
 8742 
 
 8719 
 
 8695 
 
 8671 
 
 8646 
 
 8622 
 
 8598 
 
 8573 
 
 80 
 
 8768 
 
 8746 
 
 8723 
 
 8701 
 
 8G78 
 
 8654 
 
 8631 
 
 8608 
 
 8584 
 
 8560 
 
 8535 
 
 851 1 8487 
 
 8462 
 
 8437 
 
 85 
 
 8627 
 
 8604 
 
 8581 
 
 8558 
 
 8535 
 
 8511 
 
 8488 
 
 8404 
 
 8440 
 
 8416 
 
 8392 
 
 8367 I 8343 
 
 8318 
 
 8293 
 
 90 
 
 8472 
 
 8449 8426 
 
 8426 
 
 8380 
 
 8356 
 
 8332 
 
 8308 
 
 8284 
 
 8260 
 
 8235 
 
 8211 8186 
 
 8161 
 
 8136 
 
 TABLE TV. Volumes of Alcohol of Specific Gravity 7939 at 60 Fahr. which would be 
 contained at 60 Fahr. in 100 measures of Spirit exhibiting at the several Tempera- 
 tures (Fahr.} stated at the heads of the columns the following apparent Specific Gra- 
 vities as determined with a Glass vessel or instrument. 
 
 Volumes 
 of 
 Alcohol. 
 
 30. 
 
 35. 
 
 40. 
 
 45. 
 
 50. 
 
 55. 
 
 60. 
 
 65. 
 
 70. 
 
 75. 
 
 80. 
 
 85. 
 
 
 5 
 10 
 15 
 20 
 
 9994 
 9924 
 9$ 68 
 9823 
 9786 
 
 9997 
 9926 
 9869 
 9822 
 9782 
 
 9997 
 9929 
 98U8 
 9820 
 9777 
 
 9998 
 9!<26 
 9867 
 !i817 
 9772 
 
 9997 
 9925 
 9865 
 9813 
 9766 
 
 9994 
 9922 
 9861 
 9807 
 9759 
 
 9991 
 9919 
 9857 
 9802 
 9751 
 
 9987 
 9915 
 9852 
 9796 
 9743 
 
 9981 
 9909 
 9845 
 9788 
 9735 
 
 9976 
 9903 
 9839 
 9779 
 9723 
 
 9970 
 9897 
 9831 
 9771 
 9713 
 
 9962 
 9889 
 9823 
 9761 
 9701 
 
 25 
 30 
 M 
 40 
 45 
 
 9752 
 9715 
 9668 
 9609 
 9535 
 
 9745 
 9705 
 9655 
 9594 
 9518 
 
 9737 
 9694 
 9G41 
 9577 
 9500 
 
 9729 
 9683 
 9627 
 9560 
 9482 
 
 9720 
 9671 
 3612 
 9544 
 9464 
 
 9709 
 9653 
 9598 
 9527 
 9445 
 
 9700 
 9546 
 1)583 
 9510 
 9427 
 
 9690 
 9633 
 9567 
 9493 
 
 9408 
 
 9678 
 9619 
 9551 
 9474 
 
 9388 
 
 9666 
 9605 
 9535 
 9456 
 9369 
 
 9653 
 9590 
 9518 
 9438 
 9350 
 
 9640 
 9574 
 9500 
 9419 
 9329 
 
 50 
 55 
 60 
 65 
 70 
 
 9449 
 9354 
 9249 
 9140 
 9021 
 
 9431 
 9335 
 
 9'230 
 9120 
 9001 
 
 9413 
 9316 
 9210 
 9009 
 8980 
 
 9393 
 
 9295 
 9189 
 9078 
 8958 
 
 9374 
 9'275 
 9168 
 9056 
 8936 
 
 9354 
 
 9254 
 9147 
 9034 
 8913 
 
 9335 
 9234 
 9126 
 9013 
 
 8892 
 
 9315 
 9213 
 9105 
 
 8992 
 8870 
 
 9294 
 9192 
 
 9083 
 8969 
 8847 
 
 9-->74 
 9171 
 JOfil 
 8947 
 8825 
 
 9253 
 9150 
 9039 
 
 8924 
 8801 
 
 J232 
 9128 
 9016 
 8901 
 
 8778 
 
 75 
 80 
 85 
 90 
 
 8896 
 8764 
 8623 
 8469 
 
 8875 
 8743 
 8601 
 8446 
 
 8854 
 8721 
 8579 
 8423 
 
 8832 
 8699 
 8556 
 8401 
 
 8S10 
 8676 
 8533 
 8379 
 
 8787 
 8653 
 8510 
 8355 
 
 8765 
 8631 
 8488 
 8332 
 
 8743 
 8609 
 8165 
 8309 
 
 8720 
 8585 
 8441 
 
 8285 
 
 8697 
 8562 
 8468 
 8262 
 
 8673 
 853S 
 8.394 
 8238 
 
 8619 
 8514 
 8370 
 8214 
 
 REDUCTIONS FOR A Brass INSTRUMENT. 
 
 To be deducted from 
 -5 I -4 
 
 the Specific Gravities. 
 -3 | -2| -2 
 
 ITo be addec 
 | +1 
 
 I to the Specific Gravit 
 +2 1 +2 | +3 
 
 ies. 
 +4 
 
ALCOHOLOMETRY. 89 
 
 In Table III. the specific gravity of the spirit is supposed to be compared with that 
 of water at the maximum density, and to be corrected for the expansion of the vess< 
 or instrument with which the determination is made. These densities may be reduced 
 to those compared with water at 60 F. (as in Table II.), by multiplying them all by 
 1-0009. .,, 
 
 To find by means of this table the strength of a spirit, when either the specific 
 gravity or the temperature is not given exactly as in the tables, we proceed by interpo- 
 lation as in the calculations connected with Table II. (p. 85.) But if neither tempe- 
 rature nor specific gravity is exactly given in the table, the calculation is made as in 
 the following example. Let it be required to find the strength of a spirit of sp. gr. 
 0-9321 at 77 F. 
 
 Specific Gravity 
 
 Per cent, of Alcohol. at 75 F. at 80 F. Difference. 
 
 45 9367 9347 20 
 
 50 9272 9251 21 
 
 Difference T 95 96 
 
 Hence the sp. gr. for 77 F., and for : 
 
 on 
 
 45 p. c. alcohol is 9367-2 x ^ = 9359 
 o 
 
 50 9272-2 x ^ = 9263-6 
 
 Difference = 95'4 
 
 Calling this difference 95, it follows that to each 1 per cent, of alcohol there corre- 
 sponds at 77 F. a difference of 19 in the specific gravity, and consequently the volume 
 per cent, of alcohol corresponding to the specific gravity 9321 is 
 
 45 + 9359 - 9321 =45+ 38 =47Tolpe- 
 
 This result shows that the spirit in question, when cooled down to the normal tem- 
 perature of 60 F. contains in 100 measures, 47 measures of absolute alcohol; this is 
 not, however, the actual proportion by volume at 77, because alcohol and water ex- 
 pand at different rates. 
 
 Table IV. exhibits in the same manner as Table III. the strength of spirit according 
 to its specific gravity, but on the supposition that the specific gravity is determined 
 with a glass instrument, and is not corrected for the expansion of the glass : hence 
 the expression " apparent specific gravity." 
 
 If the specific gravity of a sample of spirit has been determined at one temperature 
 and its volume measured at another, the amount of alcohol in it may be calculated as 
 in the following example : 350 quarts of spirit are measured out at 75 F., and the 
 specific gravity determined with a glass instrument at 65 F. is 0-8609. By Table IV. 
 the strength of this spirit is 80 per cent., that is to say, 100 volumes of it measured at 
 60 F. contain 80 vol. of alcohol. By Table III. the specific gravities of spirit of 80 
 per cent, for the temperatures 60 and 75 are 8631 and 8560. Consequently the volumes 
 of a given weight of the spirit at 60 and 75 are as 8560 : 8631, and therefore the 350 
 
 quarts of spirit would, if cooled to 60, measure 350 x . = 347*12 quarts; and this 
 
 8631 
 
 volume of liquid at the strength of 80 per cent, contains 277*7 quarts of real alcohol 
 
 To ensure perfect accuracy, the expansion of the vessel in which the spirit is measured 
 ought to be taken into account ; but for commercial purposes, to which calculations of 
 this kind chiefly apply, this correction is too small to be of any importance. 
 
 The quantity of alcohol of 60 F. in 100 volumes of spirit of the same temperature 
 is called the strength (StarJce; force), of the spirit ; and the quantity of alcohol of 60 F. 
 in 100 volumes of spirit of any given temperature is called the real amount of alcohol 
 (wahrer Alkoholgehalt ; Bichesse). Thus in the example just given, the strength of the 
 
 077.7 
 
 spirit is 80. but the real amount of alcohol is x 100 = 79'3. 
 
 350 
 
 The following Tables, V. and VI., exhibit the strength and the real amount of alcohol 
 of a sample of spirit, according to the indications of the alcoholometer and the ther- 
 mometer. If, for example, the alcoholometer marks 75 per cent, in a spirit whose 
 temperature is 50 F., we find from line 16, column 6, of Table V. that the strength 
 of the spirit is 767, and from the corresponding place in Table VI. that its real amount 
 of alcohol is 77*1 per cent. 
 
ALCOIIOLOMETRY. 
 
 TABLE V. Showing the Amount of Alcohol which a given sample of Spirit would 
 contain at 60 F. according to the indication of a glass Alcoholometer, immersed in it 
 at any oilier temperature. 
 
 9 
 
 
 S| 
 
 Strength of the Spirit, when tested by the Alcoholometer at the following temperatures. 
 
 ll 
 
 
 
 2 
 
 4 
 
 f, 
 
 8 
 
 10 
 
 12 
 
 14 
 
 16 
 
 18 
 
 20 
 
 22 
 
 54 R 
 
 - 
 
 
 
 2 5 
 
 5 
 
 7'5 
 
 10 
 
 12'5 
 
 15 
 
 17-5 
 
 20 
 
 22-5 
 
 25 
 
 27'5 
 
 30 C. 
 
 !< 
 
 32 
 
 36-5 
 
 41 
 
 45-5 
 
 50 
 
 54-5 
 
 59 
 
 63-5 
 
 68 
 
 72-5 
 
 77 
 
 81-5 
 
 % F. 
 
 
 
 0-3 
 
 0-4 
 
 0-4 
 
 0-4 
 
 0-4 
 
 0-2 
 
 
 
 
 
 
 
 
 
 5 
 
 5-4 
 
 5-5 
 
 ft* 
 
 5-5 
 
 5-4 
 
 5-2 
 
 5-0 
 
 4~7 
 
 ~4'4 
 
 4-1 
 
 ~3-7 
 
 3-2 
 
 2-5 
 
 10 
 
 11-2 
 
 11-1 
 
 11-0 
 
 10-9 
 
 10-7 
 
 10-4 
 
 10-1 
 
 9-7 
 
 9'2 
 
 8-8 
 
 8-3 
 
 7'8 
 
 7-3 
 
 15 
 
 17'8 
 
 17-4 
 
 17-0 
 
 1G-5 
 
 16-0 
 
 15-6 
 
 15-1 
 
 14-6 
 
 14-0 
 
 13-4 
 
 12-8 
 
 12-2 
 
 11*6 
 
 20 
 
 24-7 
 
 23-9 
 
 23 1 
 
 2-2-3 
 
 21-7 
 
 .209 
 
 20-2 
 
 19-5 
 
 18-8 
 
 18-0 
 
 17-2 
 
 16- 5 
 
 15 7 
 
 
 31-2 
 
 30-1 
 
 28-9 
 
 280 
 
 27-1 
 
 26-1 
 
 25-2 
 
 24'4 
 
 23-5 
 
 22-5 
 
 21-6 
 
 20-7 
 
 198 
 
 30 
 
 365 
 
 35-4 
 
 34-3 
 
 333 
 
 32-3 
 
 31-3 
 
 30 2 
 
 29-2 
 
 29-3 
 
 273 
 
 26-3 
 
 25 3 
 
 2J-3 
 
 35 
 
 41-4 
 
 40-4 
 
 39-3 
 
 38-3 
 
 37-3 
 
 30-2 
 
 35-2 
 
 31-2 
 
 33 2 32-2 
 
 3!'2 
 
 302 
 
 29-1 
 
 40 
 
 46-1 
 
 45'1 
 
 44-1 
 
 43-1 
 
 42-1 
 
 41-2 
 
 40-2 
 
 39'2 
 
 38-2 37-2 
 
 36-2 
 
 3V2 
 
 34-2 
 
 45 
 
 50-8 
 
 50-0 
 
 49-0 
 
 48-1 
 
 47-1 
 
 46 2 
 
 45-2 
 
 44'2 
 
 43-2 42-3 
 
 41-3 
 
 40-4 
 
 3!>'4 
 
 
 
 55-6 
 
 54-7 
 
 53-9 
 
 53-0 
 
 52 
 
 51-1 
 
 so-s 
 
 49-3 
 
 48-4 47'4 
 
 46-5 
 
 4.V5 
 
 44-6 
 
 55 
 
 60-4 
 
 59-5 
 
 SB- 7 
 
 57-8 
 
 56'9 
 
 56-1 
 
 55-2 
 
 54-4 
 
 53-5 
 
 526 
 
 51-6 
 
 50-7 
 
 49'7 
 
 60 
 
 65-2 
 
 64-4 
 
 63-6 
 
 62-7 
 
 61-9 
 
 61-1 
 
 60-2 
 
 59-4 
 
 53-5 
 
 57-6 
 
 5G7 
 
 55-8 
 
 54-9 
 
 65 
 
 70-0 
 
 69-3 
 
 68-5 
 
 677 
 
 66-9 
 
 66-1 
 
 65-2 
 
 64-4 
 
 635 
 
 62-7 
 
 61-8 
 
 (.0-9 
 
 59-9 
 
 70 
 
 74-8 
 
 74-1 
 
 73-4 
 
 72-6 
 
 7T8 
 
 71-0 
 
 70-2 
 
 69-4 
 
 68-6 
 
 C7-8 
 
 66-9 
 
 66-1 
 
 65-2 
 
 75 
 
 797 
 
 79-0 
 
 78-2 
 
 77-4 
 
 76-7 
 
 75-9 
 
 75-2 
 
 74-4 
 
 73-7 
 
 72-8 
 
 72-0 
 
 71-2 
 
 70-3 
 
 80 
 
 84-4 
 
 83-7 
 
 83-0 82-3 
 
 81-6 
 
 80-9 
 
 80-2 
 
 79-4 
 
 78-7 
 
 779 
 
 77-2 
 
 76-4 
 
 75-6 
 
 85 
 
 89-1 
 
 88-5 
 
 87-8 
 
 87-2 
 
 86-5 
 
 85-8 
 
 85-1 
 
 84-5 
 
 83-7 
 
 83-0 
 
 82-3 
 
 81-5 
 
 80-8 
 
 90 
 
 93-7 
 
 9:5-2 
 
 92-6 
 
 92-0 
 
 91-4 
 
 90-8 
 
 90-1 
 
 89-5 
 
 88-8 
 
 88-2 
 
 87-5 
 
 86-8 
 
 86-1 
 
 06 
 
 98'2 
 
 97-7 
 
 97-1 
 
 96*7 
 
 96-1 
 
 95-6 
 
 95-1 
 
 94-6 
 
 94-0 
 
 93'4 
 
 92-8 
 
 92'8 
 
 91-fi 
 
 100 
 
 
 
 
 """ 
 
 ~~ 
 
 " 
 
 
 
 lOO'J 
 
 99-6 
 
 99-1 
 
 98-5 
 
 98'0 
 
 97-5 
 
 972 
 
 TABLE VI. Showing the Real Amount of Alcohol in Spirit at different Temperatures 
 according to the indications of a glass Alcoholometer. 
 
 55 
 
 R?al Amount of Alcohol at the following Temperatures. 
 
 o| 
 
 
 ll 
 
 
 
 2 
 
 4 
 
 6 
 
 8 
 
 10 
 
 12 
 
 14 
 
 16 
 
 18 
 
 20 
 
 22 
 
 24 R. 
 
 
 
 
 25 
 
 5 
 
 7'5 
 
 10 
 
 1 2-5 
 
 18 
 
 17-5 
 
 20 
 
 22-5 
 
 25 
 
 275 
 
 30 C 
 
 
 32 
 
 36-5 
 
 41 
 
 45-5 
 
 50 
 
 54-5 
 
 59 
 
 63-5 
 
 68 
 
 72T) 
 
 77 
 
 81-5 
 
 86 F 
 
 "= < 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 o 
 
 0-3 
 
 0'4 
 
 0-4 
 
 0-4 
 
 0-4 
 
 02 
 
 
 . 
 
 
 _ 
 
 
 
 
 5 
 
 5-4 
 
 5-5 
 
 5-5 
 
 8-5 
 
 5-4 
 
 5-2 
 
 ~5'0 
 
 4-7 
 
 4-4 
 
 4-1 
 
 1-7 
 
 3-2 
 
 2-5 
 
 10 
 
 11*1 
 
 11-1 
 
 11-0 
 
 10-9 
 
 10-7 
 
 10-4 
 
 10-1 
 
 9'7 
 
 9-2 
 
 8-7 
 
 8-3 
 
 7-8 
 
 7'3 
 
 15 
 
 17-7 
 
 17-4 
 
 17'1 
 
 16-4 
 
 160 
 
 15-5 
 
 15-1 
 
 14-5 
 
 14-0 
 
 13-4 
 
 12-8 
 
 12-2 
 
 11-5 
 
 20 
 
 24-9 
 
 240 
 
 23-1 
 
 22-4 
 
 21-7 
 
 21-0 
 
 20-2 
 
 19-5 
 
 18-8 
 
 18-0 
 
 17-2 
 
 16-4 
 
 156 
 
 25 
 
 31-3 
 
 30-2 
 
 29-2 
 
 28-2 
 
 27-2 
 
 26-2 
 
 252 
 
 24-3 
 
 23-4 
 
 22-5 
 
 216 
 
 20-7 
 
 19-8 
 
 30 
 
 37-0 
 
 357 
 
 34-6 
 
 33-4 
 
 32-4 
 
 31-3 
 
 302 
 
 29-2 
 
 28-2 
 
 27-2 
 
 26-2 
 
 25-2 
 
 24-2 
 
 35 
 
 42-0 
 
 40-7 
 
 39-6 
 
 38-5 
 
 37-4 
 
 3'2 
 
 35-2 
 
 34-1 
 
 33-1 
 
 32-1 
 
 31-0 
 
 30-0 
 
 28-9 
 
 40 
 
 466 
 
 45-5 
 
 14-5 
 
 434 
 
 42-3 
 
 41-2 
 
 40-2 
 
 3'J-l 
 
 38'0 
 
 37-0 
 
 360 
 
 35-0 
 
 33-9 
 
 45 
 
 51-5 
 
 50-4 
 
 494 
 
 48-3 
 
 47-3 
 
 46-2 
 
 45 2 
 
 44-2 
 
 43-1 
 
 42-1 
 
 41-1 
 
 40-0 
 
 39-0 
 
 50 
 
 56-3 
 
 553 
 
 54-3 
 
 53-3 
 
 52-3 
 
 51-2 
 
 50-2 
 
 492 
 
 48-2 
 
 47'1 
 
 40- 1 
 
 45 
 
 44-0 
 
 55 
 
 6I"_> 
 
 60-2 
 
 59-2 
 
 58-2 
 
 57-2 
 
 56-2 
 
 55-2 
 
 M-2 
 
 53-2 
 
 52-2 
 
 51-2 
 
 50-2 
 
 49-2 
 
 60 
 
 66-2 
 
 6V 2 
 
 64-2 
 
 632 
 
 62-2 
 
 61-2 
 
 CO-2 
 
 59-2 
 
 r.8-2 
 
 57-2 
 
 56-3 
 
 553 
 
 54 3 
 
 65 
 
 71-1 
 
 70-1 
 
 fi9M 
 
 6H-1 
 
 67-2 
 
 66-2 
 
 65-2 
 
 64-2 
 
 63-3 
 
 62-3 
 
 61-3 
 
 60-3 
 
 59-3 
 
 70 
 
 76-0 
 
 750 
 
 74-1 
 
 73-1 
 
 72-1 
 
 71 I 
 
 702 
 
 69 3 
 
 68-3 
 
 67-3 
 
 66-4 
 
 65-4 
 
 64-4 
 
 75 
 
 80'9 
 
 79-9 
 
 79-0 
 
 78-1 
 
 77-1 
 
 76-1 
 
 75-2 
 
 743 
 
 733 
 
 72-3 
 
 71-4 
 
 70-4 
 
 G9-4 
 
 80 
 
 85-7 
 
 849 
 
 839 
 
 83-0 
 
 82-0 
 
 81-1 
 
 80-2 
 
 79-3 
 
 7K-3 
 
 774 
 
 7C-4 
 
 75-5 
 
 74 5 
 
 85 
 
 90-5 
 
 89- .", 
 
 88-8 
 
 87-9 
 
 87-0 
 
 86-1 
 
 85-2 
 
 84-3 
 
 83-4 
 
 8-2-4 
 
 81-5 
 
 80-6 
 
 7<CG 
 
 90 
 
 950 
 
 91-1 
 
 93-5 
 
 9-2-7 
 
 91-!t 
 
 91 -n 
 
 90-2 
 
 x<)-3 
 
 8H-4 
 
 87-5 
 
 86'8 
 
 85-7 
 
 84-8 
 
 95 
 
 99-5 
 
 986 
 
 98-0 
 
 97-1 
 
 965 
 
 95-8 
 
 <).V.> 
 
 91-3 
 
 9H'5 
 
 92-7 
 
 91-9 
 
 91-1 
 
 <)0-2 
 
 100 
 
 
 
 
 
 
 
 
 100-8 
 
 100-2 
 
 99- C 
 
 99-0 
 
 98-3 
 
 97-6 
 
 J6-9 
 
 95-7 
 
 The scale of Tralles' alcoholometer is constructed as follows. Suppose the cylindrical 
 or prismatic stem of the instrument to be divided into a number of equal parts, of 
 arbitrary length ; and let v be the volume of that portion of the neck between two 
 consecutive divisions ; V the volume of liquid of sp. gr. 1, displaced by the alcoholo- 
 meter, and P the weight of the alcoholometer ; then 
 
 P = V.I. 
 
 If now the division to which the instrument sinks in this liquid be marked 0, the 
 divisions being numbered upwards therefrom, and if the instrument be immersed in 
 spirit of specific gravity s to the mark n, we have 
 
 P = ( V + n v} s, 
 which equations give, 
 
 V l\ \ V 1 ? 
 
 r-(r + ).,-- (--i) -f--r 
 
ALCOHOLOMETRY. 
 
 91 
 
 The arbitrary quantity v is fixed by Tralles at such a magnitude that 
 
 1 5 
 
 n = 10000 - 
 s 
 
 Now for 60 F. the specific gravity of water compared with that of water at its maxi- 
 mum density (Table I.) is 0-9991 : hence for the division in which the instrument 
 sinks in pure water at 60, we find, 
 
 1-0-9991 
 n = 10000 - Q . 9991 = 9. 
 
 Again, spirit of 80 per cent, has at 60 F. the sp. gr. 0'8631 : hence, for the division 
 to which the instrument sinks therein, we have 
 
 : 10000 . 
 
 1-0-8631 
 
 = 1587, 
 
 0-8631 
 
 and in like manner the values of the other divisions of the scale may be found : they 
 are given in Table VII. 
 
 To graduate an alcoholometer by means of this table, the instrument is first im- 
 mersed in pure water at 60 F., and the point of the stem to which it sinks is marked 
 9. It is next immersed in spirit of known strength, and the point marked to which 
 it sinks when the liquid is at 60 F. Thus if spirit of 90 per cent, be used, the num- 
 ber of the division will be 
 
 1 0-8340 
 n = 1000 ' 0-8340 = 2002 - 
 
 The interval between these two marks is then to be divided into 2002-9 = 1993 
 equal parts, and the divisions continued upwards as far as 2597, which corresponds 
 to absolute alcohol. The percentages in the first column of Table VII. are then 
 marked on the scale by the side of the numbers of the divisions in the second 
 column. 
 
 To verify the scale of an alcoholometer already divided, the specific gravities of a 
 number of samples of spirit varying in strength by nearly equal intervals between 
 and 100 per cent, may be determined by any of the ordinary methods ; the correspond- 
 ing strength found from Tables L, II., or III. ; the temperatures of them all then 
 reduced to 60 F. ; and the alcoholometer immersed in them in order to ascertain 
 whether its indications agree with the strengths so determined. The intermediate 
 points may be tested by comparison with the numbers in the columns of Table VII. 
 marked " Differences." 
 
 TABLE VII. Alcoholometer-scale for Volumes per Cent, at 60 F. 
 
 Amount 
 of Alcohol 
 by 
 Volume. 
 
 Length of 
 immersed 
 part of 
 Stem. 
 
 Differ- 
 
 euces. 
 
 Amount 
 of Alcohol 
 by 
 Volume. 
 
 Length of 
 immersed 
 part of 
 Stem. 
 
 Differ- 
 ences. 
 
 Amount 
 of Alcohol 
 by 
 
 Volume. 
 
 Length of 
 immersed 
 part of 
 Stem. 
 
 Differ- 
 ences. 
 
 
 
 9 
 
 
 22 
 
 277 
 
 11 
 
 44 
 
 588 
 
 19 
 
 1 
 
 24 
 
 15 
 
 23 
 
 288 
 
 11 
 
 45 
 
 608 
 
 20 
 
 2 
 
 39 
 
 15 
 
 24 
 
 299 
 
 11 
 
 46 
 
 628 
 
 20 
 
 3 
 
 54 
 
 15 
 
 25 
 
 310 
 
 11 
 
 47 
 
 648 
 
 20 
 
 4 
 
 68 
 
 14 
 
 26 
 
 321 
 
 11 
 
 48 
 
 669 
 
 21 
 
 5 
 
 82 
 
 14 
 
 27 
 
 332 
 
 11 
 
 49 
 
 690 
 
 21 
 
 6 
 
 95 
 
 13 
 
 28 
 
 344 
 
 12 
 
 60 
 
 712 
 
 22 
 
 7 
 
 108 
 
 13 
 
 29 
 
 355 
 
 11 
 
 51 
 
 735 
 
 23 
 
 8 
 
 121 
 
 13 
 
 30 
 
 367 
 
 12 
 
 52 
 
 758 
 
 23 
 
 9 
 
 133. 
 
 12 
 
 31 
 
 380 
 
 13 
 
 53 
 
 782 
 
 24 
 
 10 
 
 145 
 
 12 
 
 32 
 
 393 
 
 13 
 
 54 
 
 806 
 
 24 
 
 11 
 
 157 
 
 12 
 
 33 
 
 407 
 
 14 
 
 55 
 
 830 
 
 24 
 
 12 
 
 169 
 
 12 
 
 34 
 
 420 
 
 13 
 
 56 
 
 854 
 
 24 
 
 13 
 
 180 
 
 11 
 
 35 
 
 434 
 
 14 
 
 57 
 
 879 
 
 25 
 
 14 
 
 191 
 
 11 
 
 36 
 
 449 
 
 15 
 
 58 
 
 905 
 
 26 
 
 15 
 
 202 
 
 11 
 
 37 
 
 465 
 
 16 
 
 59 
 
 931 
 
 26 
 
 16 
 
 213 
 
 11 
 
 38 
 
 481 
 
 16 
 
 60 
 
 957 
 
 26 
 
 17 
 
 224 
 
 11 
 
 39 
 
 498 
 
 17 
 
 61 
 
 984 
 
 27 
 
 li 
 
 235 
 
 11 
 
 40 
 
 5i5 
 
 17 
 
 62 
 
 1011 
 
 27 
 
 19 
 
 245 
 
 10 
 
 41 
 
 533 
 
 18 
 
 63 
 
 1039 
 
 28 
 
 20 
 
 256 
 
 10 
 
 42 
 
 551 
 
 18 
 
 64 
 
 1067 
 
 28 
 
 21 
 
 266 
 
 10 
 
 43 
 
 569 
 
 18 
 
 65 
 
 1096 
 
 29 
 
92 
 
 ALCOHOLOMETRY. 
 
 TABLE VII (continued}. 
 
 Amount 
 
 Length of 
 
 
 Amount 
 
 Length of 
 
 
 Amount 
 
 Length of 
 
 
 of Alcohol 
 
 Immersed 
 
 Differ- 
 
 of Alcohol 
 
 immersed 
 
 Differ- 
 
 of Alcohol 
 
 immersed 
 
 Differ- 
 
 by 
 Volume. 
 
 part of 
 Stem. 
 
 ences. 
 
 by 
 Volume. 
 
 part of 
 Stem. 
 
 ences. 
 
 by 
 Volume. 
 
 part of 
 Stem. 
 
 ences. 
 
 66 
 
 1125 
 
 29 
 
 78 
 
 1514 
 
 36 
 
 90 
 
 2002 
 
 47 
 
 67 
 
 1154 
 
 29 
 
 79 
 
 1550 
 
 36 
 
 91 
 
 2050 
 
 48 
 
 68 
 
 1184 
 
 30 
 
 80 
 
 1587 
 
 37 
 
 92 
 
 2099 
 
 49 
 
 69 
 
 1215 
 
 31 
 
 81 
 
 1624 
 
 37 
 
 93 
 
 2150 
 
 51 
 
 70 
 
 1246 
 
 31 
 
 82 
 
 1662 
 
 38 
 
 94 
 
 2203 
 
 53 
 
 71 
 
 1278. 
 
 32 
 
 83 
 
 1701 
 
 39 
 
 95 
 
 2259 
 
 56 
 
 72 
 
 1310 
 
 32 
 
 84 
 
 1740 
 
 39 
 
 96 
 
 2318 
 
 59 
 
 73 
 
 1342 
 
 32 
 
 85 
 
 1781 
 
 41 
 
 97 
 
 2380 
 
 62 
 
 74 
 
 1375 
 
 33 
 
 86 
 
 1823 
 
 42 
 
 98 
 
 2447 
 
 67 
 
 75 
 
 1409 
 
 34 
 
 87 
 
 1866 
 
 43 
 
 99 
 
 2519 
 
 72 
 
 76 
 
 1443 
 
 34 
 
 88 
 
 1910 
 
 44 
 
 100 
 
 2597 
 
 78 
 
 77 
 
 1478 
 
 35 
 
 89 
 
 1955 
 
 45 
 
 
 
 
 The following is a similar table for percentages by weight. 
 
 TABLE VIII. Alcoholometer-scale for Weights per Cent, at 60 F. 
 
 Amount 
 of 
 Alcohol 
 by Weight 
 
 Length of 
 immersed 
 part of 
 Stem. 
 
 Differ- 
 ences. 
 
 Amount 
 of 
 Alcohol 
 by Weight 
 
 Length of 
 immersed 
 part of 
 Stem. 
 
 Differ- 
 ences. 
 
 Amount 
 of 
 Ale., hoi 
 by Weight 
 
 Length ol 
 immersed 
 part of 
 Stem. 
 
 Differ- 
 ences. 
 
 
 
 9 
 
 _ 
 
 
 
 
 
 
 
 1 
 
 28 
 
 19 
 
 35 
 
 547 
 
 20 
 
 68 
 
 1411 
 
 31 
 
 2 
 
 46 
 
 18 
 
 36 
 
 568 
 
 21 
 
 69 
 
 1442 
 
 31 
 
 3 
 
 64 
 
 18 
 
 37 
 
 589 
 
 21 
 
 70 
 
 1473 
 
 31 
 
 4 
 
 82 
 
 18 
 
 38 
 
 610 
 
 21 
 
 71 
 
 1505 
 
 32 
 
 5 
 
 98 
 
 16 
 
 39 
 
 633 
 
 22 
 
 72 
 
 1536 
 
 31 
 
 6 
 
 114 
 
 16 
 
 40 
 
 655 
 
 22 
 
 73 
 
 1568 
 
 32 
 
 7 
 
 130 
 
 16 
 
 41 
 
 677 
 
 22 
 
 74 
 
 1600 
 
 32 
 
 8 
 
 145 
 
 15 
 
 42 
 
 700 
 
 23 
 
 75 
 
 1632 
 
 32 
 
 9 
 
 159 
 
 14 
 
 43 
 
 724 
 
 24 
 
 76 
 
 1664 
 
 32 
 
 10 
 
 173 
 
 14 
 
 44 
 
 748 
 
 24 
 
 77 
 
 1697 
 
 33 
 
 11 
 
 187 
 
 14 
 
 45 
 
 772 
 
 24 
 
 78 
 
 1730 
 
 33 
 
 12 
 
 201 
 
 14 
 
 46 
 
 797 
 
 25 
 
 79 
 
 1763 
 
 33 
 
 13 
 
 214 
 
 13 
 
 47 
 
 822 
 
 25 
 
 80 
 
 1796 
 
 33 
 
 14 
 
 227 
 
 13 
 
 48 
 
 847 
 
 25 
 
 81 
 
 1830 
 
 34 
 
 15 
 
 240 
 
 13 
 
 49 
 
 873 
 
 26 
 
 82 
 
 1865 
 
 35 
 
 16 
 
 252 
 
 12 
 
 50 
 
 899 
 
 26 
 
 83 
 
 1901 
 
 36 
 
 17 
 
 264 
 
 12 
 
 51 
 
 925 
 
 26 
 
 84 
 
 1938 
 
 37 
 
 18 
 
 277 
 
 13 
 
 52 
 
 951 
 
 26 
 
 85 
 
 1975 
 
 37 
 
 19 
 
 291 
 
 14 
 
 53 
 
 978 
 
 27 
 
 86 
 
 2012 
 
 37 
 
 20 
 
 304 
 
 13 
 
 54 
 
 1005 
 
 27 
 
 87 
 
 2050 
 
 38 
 
 21 
 
 317 
 
 13 
 
 55 
 
 1033 
 
 28 
 
 88 
 
 2088 
 
 38 
 
 22 
 
 330 
 
 13 
 
 56 
 
 1061 
 
 28 
 
 89 
 
 2126 
 
 38 
 
 23 
 
 343 
 
 13 
 
 57 
 
 1089 
 
 28 
 
 90 
 
 2165 
 
 39 
 
 24 
 
 357 
 
 14 
 
 58 
 
 1117 
 
 28 
 
 91 
 
 2204 
 
 39 
 
 25 
 
 371 
 
 14 
 
 59 
 
 1145 
 
 28 
 
 92 
 
 2254 
 
 40 
 
 26 
 
 386 
 
 15 
 
 60 
 
 1173 
 
 28 
 
 93 
 
 2286 
 
 42 
 
 27 
 
 402 
 
 16 
 
 61 
 
 1202 
 
 29 
 
 94 
 
 2329 
 
 43 
 
 28 
 
 419 
 
 17 
 
 62 
 
 1231 
 
 29 
 
 95 
 
 2372 
 
 43 
 
 29 
 
 435 
 
 16 
 
 63 
 
 1261 
 
 30 
 
 96 
 
 2415 
 
 43 
 
 30 
 
 452 
 
 17 
 
 64 
 
 1290 
 
 29 
 
 97 
 
 2458 
 
 43 
 
 31 
 
 469 
 
 17 
 
 65 
 
 1320 
 
 30 
 
 98 
 
 2503 
 
 45 
 
 32 
 
 487 
 
 18 
 
 66 
 
 1350 
 
 30 
 
 99 
 
 2549 
 
 46 
 
 33 
 
 507 
 
 20 
 
 67 
 
 1380 
 
 30 
 
 100 
 
 2597 
 
 48 
 
 34 
 
 527 
 
 20 
 
 
 
 
 
 
 
ALCOHOLOMETRY. 
 
 93 
 
 Various other hydrometers or areometers are also used for Fig. 3. 
 
 taking the specific gravity and ascertaining the strength of 
 spirits. Sik.es' s hydrometer is the one used in levying the 
 spirit duty in this country. This instrument has a four- 
 sided stem b, divided into 11 equal parts, and fitting into a 
 brass ball a, which carries at the bottom a small conical stem c, 
 terminating in a pear-shaped loaded bulb. It is also pro- 
 vided with 9 circular weights, numbered 10, 20, 30, 40, 50, 60, 
 70, 80, 90, having slits by which they fit into the stem. The 
 instrument is adjusted so as to float with the zero of the scale 
 coinciding with the surface of the liquid in spirit of specific 
 gravity 0-825 at 60F. which is the " standard alcohol" of the 
 excise (p. 82). In weaker spirit it will not sink so low; and if 
 the density of the liquid be much greater, it will be necessary 
 to add one or more of the weights, to cause the entire immer- 
 sion of the bulb. The sum of the numbers of the weights to- 
 gether with the number on the scale which is at the level 
 of the liquid, gives, by means of a table provided for the 
 purpose, the amount of proof spirit in the sample, proof 
 spirit being, according to Act of Parliament, such as at 51 
 Fahr. weighs if as much as an equal bulk of water, or in other 
 words has a specific gravity of 0-923077 at 51, or 0-919 at 
 60 F. 
 
 When spirit is said to be 30 per cent, (for example) above 
 proof, the meaning is, that 100 measures of this spirit, 
 when diluted with water, would yield 130 measures of proof ^^ ^ TnTfi ^ 
 spirit; on the other hand, spirit 30 per cent, below proof $H| lUffr! 
 contains in 100 measures, 100 30 or 70 measures of proof Mfl|/ 
 spirit. 
 
 It is often required to find the quantity of water which must be added to spirit 
 containing a given percentage of alcohol in order to reduce it to a lower percentage. 
 If the actual and required amounts are given in weights per cent., a and a f , the weight 
 x of water to be added to 100 Ibs of spirit to reduce the percentage of alcohol from 
 a to a', is given by the proportion : 
 
 100 + x : a = 100 : ', 
 
 whence x = 100 f- f 1 
 
 If, for example, spirit containing 90 Ibs. of alcohol in 100 Ibs. is to be reduced to 
 spirit containing 60 Ibs. per cent., the quantity of water required is 
 
 100 
 
 | - 1 ) 
 \oO / 
 
 100 x 0-5 = 50 Ibs. 
 
 Next, let it be required to find what volume of water must be added to 100 
 volumes of spirit containing v volumes per cent, of alcohol to reduce it to v' volumes 
 per cent. 
 
 If P be the weight, and S the specific gravity of the spirit we have : 
 
 P = 100 8. 
 
 and if to this we add w volumes of water, the weight of which will also be w (its 
 specific gravity being 1), we obtain a volume V of spirit, whose specific gravity may 
 be denoted by S', and its amount of alcohol in volumes per cent, by v'. Then, 
 
 P + w = 100 8 + w = V8', 
 and V I 100 = v : V 1 , 
 
 or, V = 100 . * 
 
 because the diluted spirit still contains the v volumes of alcohol which were present in 
 the liquid before dilution. From these two equations we find 
 
 For example, to reduce spirit of 80 volumes p. c. to spirit of 40 volumes p. c. we find, 
 w = 100 . / . 0-9519 - 0-8639^ = 103-99 
 
 so that 100 measures of the given spirit require 103-99 measures of water at 60F. to 
 reduce them from 80 to 40 per cent. 
 
S4 ALCOHOLOMETRY. 
 
 The volume of diluted spirit produced by the mixture is 
 
 Q/\ 
 
 In the example just given, 100 = 200 volumes, less therefore than the sum of 
 
 the volumes of the liquids mixed. 
 
 On the principles just explained, the numbers in the following table are calculated. 
 It must be observed, however, that the specific gravities are given as determined by 
 Gay-Lussac, and correspond to 15 C. on which account the result of the calculation 
 just given does not agree exactly with the number in the table. 
 
 The original volumes per cent, of the spirit are placed at the tops of the columns, 
 and the percentages to which they are to be reduced in the first column of the table. 
 Thus to find how much water is required to reduce spirit of 75 per cent, to 40 per cent, 
 look in the column headed 70 for the number on a level with 40 in the first column ; 
 we thus find that 7 7 "5 8 volumes is the quantity of water required: 
 
 TABLE IX. Showing the quantity of Water required to reduce 100 volumes of a 
 stronger Spirit to a Spirit of lower strength. 
 
 
 90 
 
 85 
 
 80 
 
 75 
 
 70 
 
 65 
 
 60 
 
 55 
 
 50 
 
 85 
 
 6-56 
 
 
 
 
 
 
 
 
 
 80 
 
 13-79 
 
 6-83 
 
 
 
 
 
 
 
 
 75 
 
 21-89 
 
 14-48 
 
 7-20 
 
 
 
 
 
 
 
 70 
 
 31-05 
 
 23-14 
 
 15-35 
 
 7-64 
 
 
 
 
 
 
 65 
 
 41-53 
 
 33-03 
 
 24-66 
 
 16-37 
 
 8-15 
 
 
 
 
 
 60 
 
 53-65 
 
 44-48 
 
 35-44 
 
 26-47 
 
 17*58 
 
 8-76 
 
 
 
 
 55 
 
 67-87 
 
 57*90 
 
 48-07 
 
 38-32 
 
 28-63 
 
 19-02 
 
 9-47 
 
 
 
 50 
 
 84-71 
 
 73-90 
 
 63-04 
 
 52-43 
 
 41-73 
 
 31-25 
 
 20-47 
 
 10-35 
 
 
 45 
 
 105-34 
 
 93-30 
 
 81-38 
 
 69-54 
 
 57-78 
 
 46-09 
 
 34-46 
 
 22-90 
 
 11-41 
 
 40 
 
 130-80 
 
 117-34 
 
 104-01 
 
 90-76 
 
 77-58 
 
 64-48 
 
 51-43 
 
 38-46 
 
 25-55 
 
 35 
 
 163-28 
 
 148-01 
 
 132-88 
 
 117-82 
 
 102-84 
 
 87-93 
 
 73-08 
 
 58-31 
 
 43-59 
 
 30 
 
 206-22 
 
 188-57 
 
 171-05 
 
 103-53 
 
 136-04 
 
 118-94 
 
 101-71 
 
 84-54 
 
 67'4o 
 
 25 
 
 266-12 
 
 245-15 
 
 224-30 
 
 253-61 
 
 182-83 
 
 162-21 
 
 141-65 
 
 121-16 
 
 100-73 
 
 20 
 
 355-80 
 
 329-84 
 
 304-01 
 
 278-26 
 
 252-58 
 
 226-98 
 
 201-43 
 
 175-96 
 
 150-55 
 
 15 
 
 505-27 
 
 471-00 
 
 436-85 
 
 402-81 
 
 368-83 
 
 334-91 
 
 301-07 
 
 267-29 
 
 233-64 
 
 10 
 
 804-54 
 
 753-65 
 
 702-89 
 
 651-21 
 
 601-60 
 
 551-06 
 
 500-59 
 
 450-19 
 
 399-85 
 
 A similar but much more extended table for this purpose is given by Gay-Lussac. 
 (See Haudworterbuch d. Chem. i. 504.) 
 
 To determine what quantity of a weaker spirit must be added to a stronger one to 
 produce a spirit of given mean percentage, we proceed as follows. 
 
 Let v be the volume of alcohol in 100 measures of the stronger spirit, S its specific 
 gravity, and P its weight. Also let F x be the volume of the weaker spirit added, v t its 
 percentage of alcohol, 8 1 its specific gravity, and P t its weight ; and lastly, let F 2 be 
 the volume of spirit resulting from the mixture, v 2 its percentage of alcohol, S z its spe- 
 cific gravity, and P 2 its weight. Then : 
 
 P = 100 3 : PJ. = 
 
 or 100 S + F^ = F 2 S 2 . 
 The quantity of alcohol contained in this mixture is, 
 
 P + 
 
 (1). 
 
 But since the mixed spirit is to contain F 2 volumes per cent, of alcohol, this quantity 
 of alcohol is also represented by 
 
 F 2 
 
 100 2 
 Hence the equation : 
 
 F 2 v 2 = 100 v + Fjflj. . . . (2). 
 
 And eliminating F 2 between the equations (1) and (2), we have, 
 
 100 S + F 1 S 1 
 
 r , i-i- v a = 100 v + F^v, 
 
ALCOIIOLOMETRY. 
 
 95 
 
 whence we obtain : 
 
 100 - 8 - 100 8 
 v _ v* 
 
 #1 - ^ S 2 
 
 The numerator of this fraction is the quantity of water which must be added to 100 
 volumes of the stronger spirit to produce a spirit of the required strength. The de- 
 nominator may be written in the form, 
 
 and is therefore the volume of water which must be added to * volumes of spirit con- 
 taining v 2 per cent, of alcohol to bring it to the percentage v r . 
 
 To determine the amount of alcohol in spirituous liquors, such as wine or beer, con- 
 taining foreign matters, as volatile oils, sugar, mucilage, saline substances, &c., the 
 liquid may be distilled, and the distillate, which will be free from the fixed impurities, 
 may be treated by the methods already described. Volatile oils are for the most part of 
 nearly the same specific gravity as alcohol, and the small quantities of them existing 
 in vinous liquors do not make any essential difference in the specific gravity. 
 
 Other physical characters have also been resorted to for determining the strength of 
 spirituous liquors, viz. the boiling-point, vapour-density, rate of expansion, &c. 
 
 The boiling-point of hydrated alcohol has been proposed by Groning as a means 
 of determining its strength. For this purpose, he has constructed the following 
 table. 
 
 Per Cent, 
 of Alcohol. 
 
 5 
 
 10 
 15 
 
 20 
 25 
 30 
 35 
 
 Boilir.g- 
 Point. 
 
 96-3 C. 
 92-9 
 91-0 
 89-1 
 
 87-5 
 86-2 
 85-0 
 
 Per Cent, 
 of Alcohol. 
 
 40 
 45 
 50 
 50 
 60 
 65 
 
 Boiling- 
 Point. 
 
 84-1 C. 
 
 83-4 
 
 83-1 
 
 82-2 
 
 81-9 
 
 81-5 
 
 Per Cent, 
 of Alcohol. 
 
 70 
 
 75 
 80 
 85 
 90 
 95 
 
 Boiling- 
 Point. 
 
 80-9 C. 
 
 80-3 
 
 797 
 
 79-4 
 
 79-0 
 
 78-4 
 
 According to Dalton, alcohol of 43 per cent, boils at 84 C. 
 
 J. J. Pohl (Denkschriften d. math, naturw. Classe d. Wien, Akad. II. abstr. 
 Wien, Akad. Ber. 1850 ; Marz. 246 ; Jahresber. 1850, 455) has also determined the 
 boiling-point of hydrated alcohol of various strengths. He finds that, at the commence- 
 ment of the ebullition, the thermometer remains constant for a short time, then slowly 
 rises a little, and afterwards remains constant for a somewhat longer time (from 4 to 
 16 seconds when 14-6 grms. of liquid were used). The temperatures at the second 
 stationary interval are given in the following table (Bar. at 760 mm.) 
 
 Percentage 
 of Alcohol. 
 
 . 
 
 1 . 
 
 2 . 
 
 3 . 
 
 4 . 
 
 5 . 
 6 
 
 Boiling- 
 Point. 
 
 100-00 c. 
 
 98-79 
 97-82 
 96-S5 
 95-90 
 95-02 
 94-21 
 
 Percentage 
 of Alcohol. 
 
 7 . 
 
 8 . 
 
 9 . 
 
 10 . 
 
 11 . 
 12 
 
 Boiling. 
 Point. 
 
 93-43 C. 
 
 92-70 
 
 92-03 
 
 91-40 
 
 90-83 
 
 90-27 
 
 The presence of sugar in the liquid up to 15 p. c. appears not to exert any percep- 
 tible influence on the boiling-point (a mixture of 10 pts. alcohol with 15 sugar and 75 
 water boiled at the same temperature as a mixture of 10 alcohol and 90 water). 
 
 Instruments, called Ebullioscopcs, for directly ascertaining the strength of hydrated 
 alcohol by its boiling-point, have been constructed by Broissard-Vidal and by Conaty. 
 (See a report on these instruments byDespretz, Pouillet, andBabinet, Comptrena. 
 xxvii. 374. A description and figure of a Vidal-instrument are given in the Pharm. J. 
 Trans, vii. 166.) Ure (Pharm. J. Trans, vii. 166 ; Pharm. Centr. 1847, 422) by means 
 of an instrument similar to Conaty's (which is merely an ordinary thermometer, having 
 a moveable scale which can be shifted so as to correspond with the variations of the 
 barometer, and has the percentages of alcohol marked on it) has determined the boil- 
 ing-points of hydrated alcohol as follows : 
 
96 ALCOHOL RADICLES. 
 
 Specific Boiling. I Specific Boiling. 
 
 Gravity. Point. Gravity. Point. 
 
 0-9200 
 0-9321 
 0-9420 
 0-9516 
 0-9600 
 
 81-4 C. 
 
 82-1 
 
 82-5 
 
 83-3 
 
 841 
 
 0-9665 .... 85-3 G 
 
 0-9729 .... 87-2 
 
 0-9786 .... 88-8 
 
 0-9850 .... 91-3 
 
 0-9920 94-4 
 
 Silbermann has proposed to determine the strength of hydrated alcohol by its rate 
 of expansion by heat, and has constructed an instrument for the purpose (Compt. rend. 
 xxvii. 418). A thermometer is filled up to a certain mark with the spirit at 25 C. and 
 after this liquid has been exhausted of air by the air-pump, an observation is made 
 of the amount by which it expands when heated to 50 C. The amount of alcohol is 
 then found by means of a scale graduated by direct observation upon a number of 
 samples of spirit of known strength. The indications of this instrument are not sen- 
 sib y affected by the presence of sugar or salts in the liquid. 
 
 Another instrument for the same purpose has been constructed and described by 
 Makin. (Chem. Soc. Qu. J. ii. 224.) 
 
 For further details on alcoholometry, see the new edition of lire's Dictionary of Arts, 
 Manufactures and Mines, vol. i. pp. 44-64. 
 
 ALCOHOL-RADICLES. The radicles which, when they replace half the hy- 
 drogen in a molecule of water form alcohols, are capable of uniting, though not directly, 
 with chlorine bromine, iodine, cyanogen, oxygen, sulphur, &c., with the radicles of acids, 
 and with metals : in short they exhibit in their chemical relations the character of 
 electro-positive elements or metals. Only a few of them have yet been isolated ; and 
 of these, all but one (allyl) belong to the first series of alcohols mentioned in the 
 preceding article, and are represented by the general formula OH 2n+1 , or C 2n H 4n+2 . 
 They are obtained : 
 
 1. By the action of sodium, potassium, zinc, &c., at high temperatures, on their 
 iodides or bromides. In this manner ethyl was first isolated by Frankland. 2. By 
 the electrolysis of the acids of the series C n H 8n O*. The general formula of the decom- 
 position is, 
 
 OH 2 "0 2 = O-'H 2 *-' + CO 2 + H. 
 
 In this manner, acetic acid, C 2 H 4 2 , yields methyl, CH 3 ; valeric acid, C 5 H I0 2 , yields 
 tetrylor butyl, C 4 H 9 ; caproic acid, C 5 H 12 2 , yields amyl, C 5 H 1J ; and cenanthylic acid 
 C 7 H 14 2 yields hexyl or caproyl, C 6 !! 13 . 3. Some of these radicles, viz. trityl or propyl, 
 tetryl, amyl and hexyl, are also found among the products of the dry distillation of 
 Boghead Cannel coal. (Or. "Williams, Chem. Gaz. 1857, pp. 29 and 95.) 
 
 Methyl and ethyl are gaseous at ordinary temperatures ; trityl, tetryl, amyl, and 
 hexyl, are liquids, the first boiling at 68 C, the second at 108, the third at 155, and 
 and the fourth at 202. They do not unite directly with any of the elementary bodies, 
 and it has not yet been found possible to reproduce from them, by direct union, 
 any of the bodies of the methyl, ethyl series, &c. At the moment of isolation, how- 
 ever, from their iodides by the action of metaiS, they exhibit a strong tendency to 
 unite with the metal: in this manner, zinc-ethyl, C 2 H 5 Zn and zinc-methyl, C 2 H 3 Zn, are 
 formed by the action of zinc on the iodides of those radicles. 
 
 The constitution of these bodies has given rise to considerable discussion. The 
 formulae CH 3 , C 2 H 5 , &c., originally assigned to them by Frankland and Kolbe, repre- 
 sent their vapours as condensed to 1 volume, whereas the usual mode of condensation 
 in organic compounds is to 2 volumes (see ATOMIC VOLUME). For this reason, and 
 likewise because all organic compounds whose formulae are well established, are found 
 to contain even numbers of hydrogen-atoms, Gerhardt (Compt. chim. 1848, 19; 
 
 1849, 11) proposed to double the formulae of these radicles in the free state, making 
 
 PITTS ) r*2TT5 ) 
 
 them C 2 H S or njp[> C 4 H 10 or X>jp[ &<* This duplication of the formulae was after- 
 
 wards supported byHofmann (Chem. Soc. J. iii. 121) on the ground that the boiling- 
 points of the consecutive terms of the series of these bodies differ by about 47 C., an in- 
 terval more than double of that which generally corresponds to a difference of CH 2 in 
 bodies of the methyl, ethyl, trityl series, &c. But the decisive argument in favour of the 
 double formulae is afforded by the experiments of Wurtz, who has shown that by the 
 action of mixtures of the iodides of these radicles (iodide of ethyl and iodide of tetryl, 
 for example) with sodium, or by the electrolysis of a mixture of the potassium-salts of 
 two fatty acids, e. a. acetate and oenanthylate of potassium, compound radicles are ob- 
 
 tained, viz. ethyl-tetryl, 4T j 9 Lmethyl-hexyl, 6 Tj 13 > &c.; and moreover that when 
 
 these mixed radicles are compared with the simple radicles with double formulae, a 
 regular gradation of physical properties is observed as the number of atoms in the 
 molecule increases. This will be seen from the following table. 
 
ALCOHOLS. 
 
 97 
 
 Radicle. 
 
 Formula. 
 
 Specific 
 Gravity at 
 ti C. 
 
 Vapour-Density 
 
 Boiling- 
 Point. 
 
 Observed. 
 
 Calculated. 
 
 Ethyl-tetryl . 
 Ethyl-amyl 
 Methyl-hexyl . 
 
 C 7 H 16 = 
 
 C 7 H 16 = 
 
 C 2 H 5 
 C 4 H 9 
 C'H 5 
 C 5 H n 
 CH 3 
 
 0-7011 
 0-7069 
 
 3-053 
 3-522 
 3-426 
 
 2-972 
 3-455 
 3-455 
 
 62 C. 
 88 
 82? 
 
 Tetryl . 
 
 C 8 H 18 = 
 
 C 4 H 9 
 
 0-7057 
 
 4-070 
 
 3-939 
 
 106 
 
 Tetryl-amyl . 
 
 C 9 H 20 = JJ^ 
 
 0-7247 
 
 4-465 
 
 4-423 
 
 132 
 
 Amyl 
 
 C'OH 22 = j*E" 
 
 0-7413 
 
 4-956 
 
 4-907 
 
 158 
 
 Tetryl-hexyl . 
 
 C"H 2 * - jg| 9 3 
 
 ? 
 
 4-917 
 
 4-907 
 
 155 
 
 Hexyl . 
 
 C12H26 = {C-H- 
 
 0-7574 
 
 5-983 
 
 5-874 
 
 202 
 
 It is clear that if the simpler formulae of tetryl, amyl and hexyl were retained, the 
 accordance between the gradation of properties and increase of atomic weight which 
 the preceding table exhibits would be completely lost. 
 
 Viewed in this light, the formation of the simple radicles is strictly analogous to 
 that of the mixed radicles, as will be seen from the following equations : 
 
 C 2 H 5 I + C'H 9 I + ZnZn = 2ZnI * C 2 H 5 .C 4 H 9 
 and 2C 2 H 5 I + ZnZn = 2ZnI +C 2 H 5 .C 2 H 5 . 
 
 AXiCOHOXiS. The term alcohol, originally limited to one substance, viz. spirit of 
 wine, is now applied to a considerable number of organic compounds, many of which, 
 in their external characters, exhibit but little resemblance to common alcohol. The 
 alcohols are all compounds of carbon, hydrogen, and oxygen. They are divided into 
 several homologous groups, but their rational formulae may all be derived from one, 
 
 TT ^ TT 2 ) TT 3 ) 
 
 two, or three molecules of water, -a- [ 0, -rp [ O 3 , -rp [ O 3 , by substitution of an or- 
 ganic radicle containing hydrogen and carbon for half the hydrogen in the type. 
 Alcohols are accordingly monatomic, diatomic, or triatomic, e.g. Ethyl-alcohol 
 
 (monatomic) = C ^0, Glycol (diatomic) = ^ C " H X|o 2 , Glycerin (tria- 
 
 H 
 
 tomic) 
 
 (C 3 H 5 )'" 
 H 3 
 
 O 3 
 
 A. IKonatomic Alcohols. 
 
 whose general formulae are OH 2 ' 
 
 1. Alcohols of the form OH 2 "*^ = 
 
 Of these there are several series, containing radicles 
 \ OH 2n - ', OH 2 "-'', C D H 2n ~ 7 - 
 
 C " ' ' 
 
 - 
 
 0. These alcohols, of which 
 
 nine, or perhaps ten, are at present known, are intimately related to the fatty acids (p. 
 50)* To every alcohol of this series there corresponds an acid of the series C n H 2n 2 , 
 which may be formed from the alcohol by oxidation, O being substituted for H 2 . The 
 following table exhibits the names and formulae of these alcohols, together with those 
 oi those of the corresponding acids : 
 
 Alcohols, 
 
 H 
 
 
 
 Methylic or protylic . . . CH 4 
 
 Ethylic or deutylic . . . C' 2 IFO 
 
 Propylic or tritylic . . . C 3 H 8 
 
 Butylic or tetrylic . . . C 4 H 1C 
 
 Amylic or pentylic . . . C 5 II 12 
 
 Caproylic or hexylic . . . C 6 H 14 
 
 CEnanthylic or heptylic . . C 7 H 16 
 
 Caprylic or octylic . . . C 8 H 18 
 
 Cetylic C 16 H 34 
 
 Cerotylic ....'. C 27 H 56 
 
 Melissylic .... CPIT^O 
 VOL. L H 
 
 Acids, 
 
 OH 2 " - >0 
 H 
 
 
 
 Formic . . . . CH 2 2 
 
 Acetic C 2 H 4 2 
 
 Propionic .... C 3 H fi 3 
 
 Butyric C 4 H 8 2 
 
 Valeric C 5 IT0 2 
 
 Caproic C fi H 12 2 
 
 CEnanthylic .... C 7 H 14 2 
 
 Caprylic .... C 8 H 16 O 2 
 
 Palmitic .... C 16 H 32 2 
 
 Cerotic C 27 H 54 2 
 
 Melissic . , 
 
98 ALCOHOLS. 
 
 These alcohols are also designated as Hydrates, or Hydratcd Oxides, of Methyl, 
 Ethyl, &c., or as Methylate, Ethylate, Tritylate, $c. of Hydrogen. The numerical tern is 
 protyl, deutyl, trityl, &c. were proposed by Gerhardt. They are in most cases pre- 
 ferable to the older names : but the terms, methyl, ethyl, and amyl, are too much con- 
 secrated by use to be discarded. 
 
 Methyl-alcohol, or wood-spirit, was first recognised as a compound similar in nature 
 and constitution to common alcohol by Dumas and Peligot in 1835. In the following 
 year, the same chemists showed that ethal (cetyl-alcohol), a substance first obtained 
 from spermaceti by Chevreul in 1823, is also of alcoholic nature. Fusel-oil was re- 
 cognised as an alcohol somewhat later by Cahours and Balard. Cerotyl-alcohol and 
 melissyl-alcohol were discovered by Brodie in 1848; octyl-alcohol by Bouis in 18.51 ; 
 tetryl-alcohol by Wurtz in 1852 ; trityl-alcohol by Chancel in 1852, and hexyl-alcohol 
 by Faget in the same year. 
 
 Methyl-alcohol is found among the products of the distillation of wood. Ethyl- 
 alcohol and the four following alcohols are produced by fermentation of sugar, 
 (C 8 H 12 6 ), perhaps in the manner represented by the following equations : 
 
 CPH^O 6 = 2C 2 H 8 + 2C0 2 
 
 Ethyl- 
 alcohol. 
 
 2C 6 H 12 8 = 2C 3 H 8 + C 2 H 6 + 4C0 2 + H 2 
 
 Trityl- Ethyl- 
 
 alcohol, alcohol. 
 
 C 6 H 12 8 = C 4 H 10 + 2C0 2 + H 2 
 
 Tetryl- 
 alcohol. 
 
 3C 6 H 12 8 = 2C 5 H 12 + C 2 H 8 + 6C0 2 + 3H0 
 
 Amyl- Ethyl- 
 
 alcohol, alcohol. 
 
 2C 6 H 12 8 = C 8 H 12 + C 3 IPO + 4C0 2 + 2H 2 
 
 Amyl- Trityl- 
 
 alcohol. alcohol. 
 
 5C 8 H 12 8 = 4C 5 H 12 + 10C0 2 + 6H 2 
 
 Amyl- 
 alcohol. 
 
 3C 6 H 12 6 = 2C 6 H 14 + 6C0 2 + 4IFO 
 
 Hexyl- 
 alcohol. 
 
 Octyl-alcohol is said to be obtained by saponifying castor-oil with potash, and dis- 
 tilling the resulting ricinolate of potassium with excess of the alkali at a high tempe- 
 rature. The ricinolic acid is then converted into octyl-alcohol, sebate of potassium, 
 and free hydrogen : 
 
 CiBH 34 3 + 2KHO = C 8 H 18 + C 10 H 16 K 2 4 + 2H 
 
 Ricinolic Octyl- Sebate of 
 
 acid. alcohol. potassium. 
 
 Bouis (Compt. rend, xxiii. 141). Other chemists, however, who have examined 
 this reaction, state that the alcohol produced by it is not octylic, but heptylic. Ac- 
 cording to Stadeler (J. pr. Chem. Ixxii. 241) two reactions take place simultaneously, 
 the one giving rise to the formation of heptylic alcohol, sebate of potassium, and 
 hydride of methyl (marsh gas), the other to the formation of methyl-cenanthyl, an acetone 
 isomeric with caprylic aldehyde, C 8 H 16 0, and free hydrogen ; thus : 
 
 C i8 H 34 3 + 2KHO = C T H 16 + C'H 16 K 2 4 + CH 3 .H 
 
 Ricinolic Heptyl- Sebate of Hydride 
 
 acid. alcohol. potassium. of methyl. 
 
 CiH 84 3 + 2KHO CH 3 .C 7 H 13 + C 10 H 16 K: 2 4 + H 4 
 
 Ricinolic Methyl- Sebate of 
 
 acid. cenanthyl. potassium. 
 
 According to Dachauer, on the contrary (Ann. Ch. Pharm. cvi. 270), the products 
 of the distillation are methyl-cenanthyl and octylic alcohol, the formation of this al- 
 cohol differing from that of methyl-oenanthyl only by the elimination of two atoms of 
 hydrogen instead of four. It does not appear that Stadeler actually observed the evo- 
 lution of marsh gas. 
 
 Cetyl-alcohol (or ethal) is obtained by decomposing spermaceti (which consists chiefly 
 of cetin,C 32 H. 64 2 ') with alkalis, palmitic acid being formed at the same time: 
 
 KHO ^ C'OH^O + C Ifl H 3I K0 3 
 
 Cetin. Cetyl- Palmitateof 
 
 alcohol. potassium. 
 
ALCOHOLS. 99 
 
 In the same manner, cerotyl-alcohol is formed from Chinese-wax, and melissyl- 
 alcohol from bees-wax. 
 
 C 54 H io8 2 + KHO = c^H^O + C 27 H M K0 2 
 
 Chinese- Cerotyl-- Cerotate of 
 
 wax. alcohol. potassium. 
 
 Some of these alcohols have also been formed from the corresponding hydrocarbons 
 OH 2 ", e. g. common alcohol from olefiant gas, C 2 H 4 , and trityl-alcohol from tritylene, 
 C 3 H 6 , by dissolving these gaseous hydrocarbons in strong sulphuric acid, and decom- 
 posing the resulting ethyl-sulphuric or trityl-sulphuric acid by distillation with water. 
 Methyl-alcohol has been formed from marsh-gas, CH 4 , by exposing that compound to 
 the action of chlorine in sunshine, whereby chloride of methyl is obtained, and decom- 
 posing this body with aqueous potash (Berthelot, Compt. rend. xlv. 916) : 
 CH 3 C1 + KHO = CH 4 + KCL 
 
 The first eight alcohols of the series are liquid at ordinary temperatures. Methylic 
 and ethylic alcohols are mobile watery liquids ; the others are more or less oily, the 
 viscidity increasing with the atomic weight! Cetyl-alcohol is a solid fat : cerotylic 
 and melissylic alcohols are waxy. 
 
 Oxidising agents convert these alcohols into aldehydes, OH 2n O, or acids, C n H 2n 2 , in 
 each case with elimination of one atom of water : 
 
 = C n H 2n O + H 2 
 and OH 8n+2 + O 2 = C n H 2n 2 + H 2 
 
 These changes take place on exposing the alcohols to the air, especially in contact with 
 platinum-black, and more quickly on distilling them with a mixture of dilute sul- 
 phuric acid and chromate of potassium. The alcohols are also converted into fatty 
 acids by heating them strongly in contact with soda-lime (a mixture of quick lime 
 with caustic soda) ; e.g. amyl-alcohol thus treated yields valerate of sodium. 
 
 The alcohols of this series contain one atom of hydrogen replaceable by metals or 
 compound radicles. Many of them, when treated with potassium or sodium, give off 
 hydrogen, and form solid compounds containing 1 atom of the alkali-metal, e. g. 
 ethylate of sodium, C 2 H 5 NaO. In this respect the alcohols partake of the nature of 
 acids. The compounds thus formed are easily decomposed, and are not easily ob- 
 tained in a definite form. 
 
 On treating these potassium- or sodium-alcohols with the iodide of an alcohol-radicle, 
 iodide of potassium or sodium is precipitated, and an ether is formed, that is to say, 
 a compound derived from an alcohol by the substitution of an alcohol-radicle for the 
 basic atom of hydrogen : thus ethylate of sodium with iodide of ethyl yields ethylic 
 ether (C-H 5 ) 2 0, and with iodide of amyl, ethyl-amyl ether, C 2 H 5 .C 5 H n .O (p. 76). 
 
 The alcohols are also converted into ethers by the action of strong sulphuric acid 
 chloride of zinc, fluoride of boron, and other powerful dehydrating agents, at a certain 
 temperature. The ultimate change is represented by the equation : 
 
 >n-H 
 
 H 
 
 r ' 
 
 Alcohol. Ether. 
 
 For the intermediate steps of the process see page 76. This particular change takes 
 place only between certain limits of temperature, e. g. for the etherification of common 
 alcohol by sulphuric acid, the limits are 140 and 160 C. At higher temperatures, a 
 further dehydration takes place, and a hydrocarbon OH> is obtained : 
 
 C"H 2 
 
 e. g. common alcohol heated above 160 with strong sulphuric acid, yields olefiant gas 
 C-'H 4 . 
 
 With the greater number of acids, alcohols yield compound ethers ; that is to say, 
 salts in which the basic hydrogen of the acid is more or less replaced by the radicle of 
 the alcohol. With monobasic acids, only neutral ethers are formed : thus common 
 alcohol heated with strong acetic acid yields acetate of ethyl, with elimination of 
 water : 
 
 C 2 H 5 ) C 2 H 3 0) C 2 H 3 
 
 _, ft 
 H H = C 2 H 5 +H0 
 
 The formation of these ethers is greatly assisted by the presence of strong sulphuric 
 or hydrochloric acid, to take up the water. They are commonly prepared either by 
 distilling the alcohol with sulphuric acid, and a salt of the other acid (e.g. acetate of 
 ethyl, by distilling alcohol witli sulphuric acid and acetate of sodium), or by passing 
 
 H 2 
 
100 ALCOHOLS. 
 
 hydrochloric acid gas into an alcoholic solution of the acid. The former method is 
 applicable to the more volatile ethers, the latter to those of higher boiling-point. 
 
 With dibasic and tribasic acids, the alcohols generally form acid ethers or alcoholic 
 acids, that is to say, compounds in which only a portion of the basic hydrogen of the 
 acid is replaced by the alcohol-radicle. Thus, when amyl-alcohol is mixed with sul- 
 
 C 5 H M ) ( S0 2 V ) 
 
 phuric acid and the mixture kept cool, amyl-sulphuric acid, TT [ SO 4 or ATTH TT ( O 2 
 
 is produced : 
 
 C 5 H) n H) q04 C 5 H) qn4 . H 
 
 H> U + TTf' 5 *-' = TT fU* + 
 ) &) H- ) 
 
 In like manner, phosphoric acid and amyl-alcohol yield amyl-phosphoric acid, 
 P0 4 .C 5 H n .H 2 . 
 
 Hydrochloric, hydrobromic, and hydriodic acids convert the alcohols of this series 
 into chlorides, &c., of the alcohol-radicles, with elimination of water : 
 
 A similar transformation is effected by the chlorides, bromides, and iodides of phos- 
 phorus: e.g. 
 
 " PC12 - C13 = c 5111 ^ 1 + HOI + POCP 
 
 Amyl- Penta- Chloride 
 
 alcohol. chloride of ofamyl. 
 
 phosphorus. 
 
 With the chlorides of acid radicles, the alcohols form compound ethers, hydrochloric 
 acid being at the same time eliminated : 
 
 Ethyl- 
 alcohol. 
 
 Persulphide of phosphorus transforms the alcohols of this series into mercaptans 
 (sulphur-alcohols) : 
 
 5OH 2n+2 + P 2 S 5 
 
 2. Alcohols of the form OH 2n O = JT ( convertible by oxidation into acids 
 
 of the form C"H 2 - 2 2 . 
 
 Only one term of this series is at present known, viz. : 
 
 Allyl-alcohol or Hydrate of AUyl, C 3 H 6 = 0. 
 
 This alcohol was discovered by Cahours and Hofmann in 1856. It is con- 
 verted by oxidising agents into acrylic aldehyde or acrolein, C 3 H 4 0, and acrylic 
 acid, C 3 H 4 2 , and moreover exhibits all the transformations of the bodies of the pre- 
 ceding series (see AXLYL). It is probable that to every acid of the series OH 2n - 2 2 
 (angelic, terebic, oleic acid, &c), there corresponds an alcohol of the form OH 2n O. 
 These alcohols are isomeric with the aldehydes of the preceding series; e.g. allyl- 
 alcohol with propionic aldehyde. 
 
 3. Alcohols of the form OH 2n - 2 = CnH ^~ 3 |o. Only one alcohol of this kind 
 is known, viz. : 
 
 Camphol, or Bornean Camphor, C 10 H 18 = JT [ 0. It is a solid substance which, 
 
 when distilled with anhydrous phosphoric acid, yields the hydrocarbon, C 10 H 16 = 
 C 10 H 18 H 2 O. It forms neutral ethers with stearic and benzoic acids. 
 
 4. Alcohols of the form C n H 2n - 6 O = H g ? | 0, and corresponding to acids of 
 the form OH 2n - 8 2 . Three of these alcohols are known, viz. : 
 Benzyl-alcohol, or Hydrate of Benzyl, C 7 H 9 jj { 
 
 Cumyl-alcohol, or Hydrate of Cumyl, C 10 H 14 = CI ** 13 } 
 Sycoceryl-alcohol, or Hydrate of Sycoccryl, 
 
ALCOHOLS. 
 
 Benzyl-alcohol was discovered by Cannizzaroin 1853; cumyl-aicbh:ol J by*Krautinl854 ; 
 these two alcohols are obtained by treating the corresponding aldehydes (bitter- 
 almond oil and cuminol) with an alcoholic solution of potash : 
 
 2C 7 H 6 + KBO = C 7 H S + C 7 H 5 K0 2 
 
 Benzyl- Benzoate of 
 alcohol. potassium. 
 
 Moreover, the aldehydes themselves may be formed from acids, by distilling a mix- 
 ture of the calcium-salt of the acid with formate of calcium, thus : 
 
 C 7 H 5 ) CO.H > Q = C 7 H 5 j 
 Ca \ CaJ H; 
 
 Benzoate of Formate Hydride of Carbonate 
 
 calcium. of calcium. of benzoyl. of calcium. 
 
 Hence it appears that these alcohols may be formed from the corresponding acids. 
 
 Benzylic and cumylic alcohols are liquids which volatilise without decomposition. 
 They are converted into aldehydes and acids by the action of oxidising agents ; they 
 form compound ethers when treated with a mixture of sulphuric acid and other 
 oxygen-acids (e.g. acetate of benzyl, C 2 H 3 2 .C 7 H 7 , is formed by treating benzyl- 
 alcohol with a mixture of sulphuric and acetic acids), and yield the chlorides of the 
 corresponding radicles when treated with hydrochloric acid ; thus chloride of benzyl, 
 C 7 H 7 C1 is obtained by treating benzyl-alcohol with strong hydrochloric acid. 
 
 With sulphuric acid or chloride of zinc, they yield resinous masses, which are 
 probably hydro-carbons analogous to olefiant gas: anhydrous boracic acid converts 
 benzyl-alcohol into benzyl-ether (C 7 H 7 ) 2 0. They do not appear to form conjugated 
 acids like ethyl- sulphuric acid. By caustic potash, at high temperatures, they are 
 converted into the corresponding acids and hydrides of the alcohol-radicles ; e.g.: 
 
 3(C 7 H 7 .H.O) = C 7 H C 2 + 2(C 7 H 7 .H) + H 2 
 
 Benzyl-alcohol. Benzoic Hydride of 
 
 acid.- benzyl. 
 
 Sycoceryl-alcohol was discovered by Warren DelaKueand Hugo Miiller,in 1859 
 (Proc. Koy. Soc. x. 298). It exists in the form of a natural acetic ether in the exuda- 
 tion from an Australian plant, the Fict(S rubiginosa. This ether is readily obtained 
 in beautiful crystals, and when treated with sodium-alcohol, yields acetic acid and 
 sycocerylic alcohol, in feathery crystals resembling caffeine or asbestos. Treated with 
 nitric acid, it yields an acid which appears tu be sycocerylic acid ; and with chromic 
 acid, it yields a product which is probably the corresponding aldehyde. 
 
 5. Alcohols isomeric with the last, but differing from them in forming conjugated 
 acids with sulphuric acid, phosphoric acid, &c., and in not being converted into acids 
 and aldehydes by the action of oxidising agents. Two of these alcohols are known, 
 
 Phenyl-alcohol, or Hydrate of 'Phenyl, C 6 H 6 = 
 Cresyl-alcohol, or Hydrate of Cresyl, C 7 H 8 = ^ O. 
 
 The former was identified as an alcohol by Laurent, in 1841 ; the latter was discovered 
 by Williamson and Fairlie, in 1854. 
 
 Both of these compounds occur among the products of the destructive distillation of 
 coal, and are separated by fractional distillation. Phenyl-alcohol is also produced by 
 the destructive distillation of salicylic acid : 
 
 C 7 H 6 3 = C 6 H 6 + CO 2 . 
 
 Phenyl-aZcohol is solid and crystalline at ordinary temperatures, melts at 35, and 
 distils without decomposition at about 185. Cresyl-alcohol is liquid at ordinary 
 temperatures. 
 
 These alcohols are easily decomposed by potassium and sodium, like common alco- 
 hols, hydrogen being evolved, and compounds formed analogous to ethylate of potas- 
 sium. They exhibit more decided acid characters than any of the preceding alcohols : 
 phenyl-alcohol indeed is sometimes called phcnic or carbolic acid : it forms a series of 
 
 salts, called phenates or carbolates, containing 1 at. metal in place of the basic hydrogen. 
 
 These alcohols are not converted into simple ethers or hydrocarbons by heating with 
 
 sulphuric acid. Strong nitric acid converts them into nitro-acids, e. g. phenyl-alcohol 
 
 into trinitrocarbolic or picric acid, C G H 3 (NO 2 ) 8 0. 
 
 H 3 
 
roe ALCOHOLS. 
 
 With pentachlb ri&e of' phosphorus, they yield a chloride and a phosphate of the 
 radicle together with hydrochloric acid : e.g. 
 
 4(C 6 H 5 .H.O) + PCP.CP = P0 4 (C 6 H 5 ) 3 + C 6 H 5 C1 + 4HC1 
 
 Hydrate of Phosphate of Chloride 
 
 phenyl. phenyl. of phenyl. 
 
 With the chlorides of the acid radicles, they form compound ethers, thus : 
 C 6 H 5 .H.O + C 7 H 5 O.C1 = C 7 IT0 2 .C 6 H 5 + HC1 
 
 Hydrate of Chloride of Benzoate of 
 
 phenyl. benzoyl. phenyl. 
 
 / > 1 n TT2n 9 ) 
 
 6. Alcohols of the form OH 2n - 8 = ^ H j 0. Two only of these bodies are 
 known, viz. : 
 
 ri9TT9 
 
 Cinnamic alcohol, Hydrate of Cinnamyl, or Styrone, C 9 H 10 jj 
 Cholesterin ...... C 2G H 44 = C ' 6]GC ^ 
 
 
 
 Styrone is obtained by heating styracin (cinnamate of cinnamyl), with caustic alkalis ; 
 cholesterin is found in the bile and other products of the animal economy. Styrone 
 is converted by oxidising agents into cinnamic aldehyde, C 9 H 8 0, and cinnamic acid, 
 C' J H 8 0*, and forms with fuming sulphuric acid a conjugated acid, the barium-salt of 
 which is soluble in water. Cholesterin heated with strong sulphuric acid gives up 
 water and forms a resinous hydrocarbon, C 26 H 42 (Zwenger, Ann. Ch. Pharm. Ixv. 
 5). Heated to 200, with acetic, butyric, benzoic, and stearic acids, it forms com- 
 pound ethers, with elimination of water, thus : 
 
 C' 8 H 35 0> n C 26 H J3 > n C 18 H 35 
 
 Stearic Cholesterin. 
 
 acid. 
 
 7. Saligenin, C 7 H 8 2 , an alcohol of the salicyl-series, and Anisic alcohvl, C 8 II I0 2 , 
 produced by the action of alcoholic potash on hydride of anisyl, C 8 H 7 2 .H, are 
 probably monatomic ; if so, they must contain oxygen-radicles, their rational formulae 
 
 O 2 
 
 p7TT7i~j ) P 8 TT 9 D ) P 7 TT6 ) 
 
 being l jjfO and H[ ; but thev may also be ^a* 01 alcohols, jf 2 ? 
 
 and TT 2 [ O 2 ' Their reactions are not sufficiently known to decide the question. 
 B. Diatomic Alcohols, or Glycols. OH 2n + 2 2 = ( C " ^2 \ O 2 . These com- 
 
 TT 2 
 
 pounds, discovered by Wurtz, are derived from a double molecule of water, TT2^ 2 > *. which 
 
 half the hydrogen is replaced by a diatomic radicle OH 2n . Four of these have been 
 obtained, viz. Efhylene-glycol, or Hydrate of Ethylene, C 2 H 6 2 
 
 lene-glycol, C 3 H S 2 , Butylene-glycol, C 4 H'0 2 , and Amylene-glycol, C 5 H 12 2 . The 
 simple name glycol is especially applied to the first of these, just as the term alco- 
 hol is especially applied to hydrate of ethyl, the most important of the monatomic al- 
 cohols. 
 
 Grlycol is obtained by treating iodide of ethylene with acetate of silver, whereby di- 
 acetate of ethylene is formed : 
 
 2 at. acetate of Diacetate of 
 
 silver. ethylene. 
 
 and heating the distilled diacetate of ethylene with potash, whereby it is decom- 
 posed, Like other compound ethers, yielding acetate of potassium and hydrate of 
 ethylene : 
 
 (C 2 H 3 2 ) 2 
 
 It was discovered by Wurtz in 1856. The other bodies of the series are obtained by 
 similar processes. They are oily liquids, which distil without decomposition. They 
 contain two atoms of basic hydrogen, one or both of which may be replaced by metals 
 or other radicles. 
 
 Glycol treated with sodium yields monosodic glycol, C' J H 4 (NaH)0 2 , and this com- 
 
ALCOHOLS. 103 
 
 pound, fused with excess of sodium, yields disodic glycol, C 2 H 4 Na 2 2 . By treating 
 monosodic glycol with iodide of ethyl, the product with potassium, and this product 
 again with iodide of ethyl, the compounds C 2 H 4 (C 2 H 5 .H)0 2 , C 2 H 4 (C 2 H 5 .K)O 2 , and 
 C 2 H 4 (C 2 H 5 ) 2 2 , are successively obtained. The last is isomeric with acetal, but not 
 identical with it (p. 3), inasmuch as it boils at a temperature 20 below that compound. 
 Dehydrating agents, such as sulphuric acid and chloride of zinc, do not act upon the 
 glycols in the same manner as upon the corresponding monatomic alcohols. Ethyl- 
 alcohol, C 2 H 5 .H.O, acted upon by sulphuric acid, or chloride of zinc, at certain tempe- 
 ratures, is converted into ether, (C 2 H 5 ) 2 0, a second atom of ethyl being introduced in 
 place of the remaining hydrogen. If glycol were acted on by these reagents in the 
 same manner, the result would be a glycolic ether containing (C 2 H 4 ) 2 2 . Instead of 
 this, the change which takes place is a simple abstraction of water, and the resulting 
 compound is aldehyde, C 2 H 4 O, a body of isomeric composition, but only half the atomic 
 weight : 
 
 H 2 = C 2 H 4 0. 
 
 Similar results are obtained with the other glycols. The aldehydes are isomeric 
 with the ethers of the diatomic alcohols (see ETHERS, and ETHYLENE, OXIDE OF); and 
 their mode of formation from these alcohols differs from the etherification of the mona- 
 tomic alcohols in the same manner as the conversion of dibasic acids into anhydrides 
 differs from that of monobasic acids, the latter being converted into anhydrides by 
 duplication of the radicle: e. g, acetic acid = C 2 H 3 O.H.O ; acetic anhydride = 
 (C*H 3 0) 2 O, whereas dibasic acids pass to the state of anhydrides by simple abstraction 
 of water, e.g. S0 4 H 2 - H 2 = SO 3 . (Wurtz, Compt. rend, xlvii. 346.) 
 
 By treating diatomic alcohols, first with hydrochloric acid and afterwards with 
 potash, compounds are obtained isomeric with the aldehydes, and resembling them in 
 some of their properties, but differing in others ; thus, ethylene-glycol, heated in a 
 sealed tube with hydrochloric acid, yields monochlorhydric glycol, C 2 H 5 C1O, a compound 
 intermediate between glycol and chloride of ethylene, C-H 4 C1 2 , and formed from glycol 
 by the substitution of Cl for 1 atom of peroxide of hydrogen : 
 
 C 2 H 4 .H 2 2 + HC1 = C 2 H 4 .HO.C1 + H 2 O; 
 
 and this compound, treated with potash, yields oxide of ethylene, a body isomeric with 
 acetic aldehyde : 
 
 C 2 H 4 .HO.C1 + KHO = C 2 H 4 + H 2 + KC1. 
 
 This oxide of ethylene resembles aldehyde in being miscible with water, and in form- 
 ing a crystalline compound with acid sulphite of sodium ; but differs from it by boiling 
 at a lower temperature, and by not forming a crystalline compound with am- 
 monia. Similar results are obtained with propylene-glycol. (Wurtz, Compt. rend. 
 xlviii. 100.) 
 
 The glycols corresponding to the other series of monatomic alcohols, have not yet 
 been obtained ; but several diatomic compound ethers containing benzylene, C 7 H 6 , have 
 been produced, viz. the acetate, valerate, and benzoate, C 7 H 6 .(O'H 3 0) 2 .0 2 , &c. ; the 
 methylate, ethylate, and amylate, C 7 H G .(CH 3 ) 2 .0 2 , &c. ; the sulphate, S0 4 .C'H 6 , and 
 the succinate, C 7 H 6 .C 4 H 4 2 .0'. The diatomic alcohol, C 7 H 6 .H>'0 2 , corresponding to 
 those compound ethers, has not yet been obtained, not being produced when the ethers 
 are decomposed by alkalis. (W. Wicke, Ann. Ch. Pharm. cii. 363.) 
 
 C. Triatomic Alcohols, or Glycerins. The general formula of these compounds 
 
 C u H 2n ~ ' ) 
 is O 3 , the radicle OH 2 "- l being equivalent to three atoms of hydrogen. One 
 
 "* /-13TT5 \ 
 
 term of the series has long been known, viz. ordinary glycerin, C 3 H 8 3 = Tr 3 > s , 
 
 the sweet oily liquid obtained in the saponification of fats. It was first shown to be a 
 triatomic alcohol by Berthelot, in 1853. (Compt. rend, xxxvii. 398.) 
 
 The neutral fats of the animal body, stearin, palmitin, olein, &c., consist of glycerin, 
 in which three atoms of hydrogen are replaced by acid radicles; and by heating 
 glycerin with acids in different proportions, a large number of compounds may b,e 
 formed, in which |, |, or the whole of the replaceable hydrogen is thus replaced, 
 the formation of these compounds being accompanied by the elimination of 1, 2, 
 or 3 atoms of water. Thus, with stearic acid, C^H^O 2 , the following compounds 
 are obtained: 
 
 Monostearin = C 21 H 4Z 4 = C 3 H 8 S + C I8 H 36 2 - H 2 O 
 Distearin = C S9 H 76 5 = C 3 H0 + 2C' 8 H 36 2 - 2H*O 
 
 - 3IFO 
 
 H 4 
 
104 ALCOHOLS. 
 
 Precisely similar actions take place on heating glycerin with hydrochloric, hydro- 
 bromic, or hydriodic acid ; but to refer the resulting compounds to the same type, it 
 is best to write the formula of glycerin thus : C 3 H 5 (HO) 3 , representing it as a compound 
 of glyceryl with 3 at. peroxide of hydrogen : then the compounds just mentioned may 
 be represented as glycerin in which 1, 2, or 3 at. peroxide of hydrogen are replaced 
 by Cl, Br, I, &c. Thus : 
 
 Monochlorhydrin = C 8 H 7 C10 2 = C 3 H 8 3 + HC1 - H 2 = C 3 H 5 C1(HO) 
 
 Pichlorhydrin = C 3 H 6 C1 2 = C 8 H 8 3 + 2HC1 - 2H 2 = C 3 H 5 C1 2 (HO) 
 
 Tricblorhydrin = C 3 H 5 C1 3 = C 8 H 8 0' + 3HC1 - 3H 2 
 
 Bromhydrodichlorhydrin = C 3 H 5 Cl 2 Br = C 3 H 8 3 + 2HC1 + HBr - 3H 2 0. 
 
 The chlorhydrins and bromhydrins are likewise produced by treating glycerin with 
 either of the bromides or chlorides of phosphorus. (See GLYCERIN.) 
 
 By treating glycerin with the chloride of an acid radicle, or by passing hydrochloric 
 acid gas into a solution of glycerin in the corresponding acid, compounds are formed 
 which may be regarded as glycerin, in which the peroxide of hydrogen is replaced 
 partly by chlorine and partly by the peroxide of the acid radicle ; thus with acetic acid 
 [Ac =. C 2 H0] : 
 
 Acetochlorhydrin = C 5 H 9 C10 S = C 8 H 8 3 + C 2 H 4 2 + HC1 - 2H 2 = 
 
 C 3 H 5 .Cl(AcO)(HO). 
 Diacetochlorhydrin = C 7 H U C10 S = C 3 H 8 3 + 2C 2 H 4 2 + HC1 - 3H 2 = 
 
 C 3 H 5 .Cl(AcO) 
 Acetodichlorhydrin = C 5 H 6 C1 2 2 = C 3 H 8 3 + C 2 H 4 2 + 2HC1 - 3H 2 = 
 
 C 3 H 5 .Cl 2 AcO. 
 (For further details, see ACETINS, p. 25.) 
 
 All these compounds, when heated with caustic alkalis, or with metallic oxides and 
 water, reproduce the acid and the glycerin ; thus stearin heated with caustic potash, 
 yields glycerin and stearate of potassium : 
 
 C3H5 C3HS C 18 H 35 
 
 Glycerin may also be formed synthetically in a similar manner to glycol, viz. by 
 heating tribromhydrin, C^^r 3 , with acetate of silver, whereby triacetin, C 3 H 5 Ac 3 3 ia 
 formed, and heating this compound with solution of caustic baryta. The other 
 glycerins have not yet been obtained in the free state, but the acetate of ethyl-glycerin 
 (C 2 H 3 ) / "Ac 3 3 appears to be obtained, together with glycol, by the action of iodide of 
 ethylene on acetate of silver. 
 
 I >. Alcohols not included in any of the preceding: groups. Berthelot 
 has shown that a considerable number of substances, not usually classed as alcohols, 
 nevertheless possess one essential character of those bodies, viz. that they unite with 
 acids, producing neutral compounds, the formation of which is attended with elimina- 
 tion of water ; and these compounds, when heated with alkalis, reproduce the sub- 
 stances from which they have been formed. The bodies in question are chiefly ot 
 a saccharine nature, viz. Mannite, C 6 H 12 5 .H 2 0, the sugar of manna; Dulcin, 
 C 6 H 11! O 5 .H'-'O, a saccharine substance from an unknown plant, brought from Mada- 
 gascar ; Finite, C 6 H 12 5 , a sugar from the Pinus lambertiana, a tree growing in 
 California ; Quercite, C 6 H 12 5 , the sugar of acorns ; Erythromannite, Erythroglucin, or 
 Phycite, C 6 H 14 8 , a sugar obtained from certain lichens, and from the Protococcus vul- 
 garis. Orcin, C 7 H S O 2 , a sweet crystalline substance, existing in the lichens which 
 yield archil and litmus ; Trehalose, C 6 H 10 5 , also a kinS. of sugar ; Glucose, C 6 H 12 6 , 
 and Meconin, C 10 H I0 4 , an acrid crystalli sable substance, obtained from opium. The 
 following are examples of the compounds formed : 
 
 C 6 H i2 5 + 2C 2 H 4 2 - 2H 2 = C 10 H I6 7 
 
 Mannitan. Acetic acid. 
 
 C 6 H I2 5 + 4C 18 H 36 2 - 2H 2 = C 78 H 152 
 
 Mannitan. Stearic acid. 
 
 C 8 H 12 5 + GC^H^O 2 - 6H 2 = 
 
 Mani.itan. Stearic acid. 
 
 2C 7 H 6 O 2 - 2H 2 = C 20 H"0 9 
 
 Phycite. Benzoic acid. 
 
 C 6 H i4 a + 6C 7 H 6 2 - 6H 2 = C 48 H 38 18 
 
 Phycite. Benzoic acid. 
 
 CH 12 + 2C J8 H 36 2 - 3H 2 = C^H^O 7 
 
 Glucose. Stearic acid. 
 
 C io H io 4 + 2C 1S H 36 2 - 2H 2 = CHO. 
 
 Meconin. Stearic acid. 
 
ALDEHYDE. 105 
 
 The compounds formed by all these bodies, excepting the last two, with acids, readily 
 yield the original saccharine substance and the acid. The compounds formed with 
 glucose are not very definite, and not easily decomposed ; but when treated with dilute 
 sulphuric acid, they yield the original acid and a fermentable sugar, which reduces 
 copper salts. (Berthelot, Compt. rend. xli. 452; xlvii. 262.) 
 
 ALDEHYDE. C 2 H 4 = C 2 H 3 O.H. [or<7 4 # 4 <9 2 = C*H*O.HO\. Acetic aldehyde, 
 Hydride of Acetyl (Gm. viii. 274; xiii. 437; Gerh. i. 658). A volatile liquid 
 produced by the oxidation and destructive distillation of alcohol and other organic 
 compounds. It was first obtained in an impure state by Dobereiner, who called it 
 Light oxygen ether, and was afterwards prepared pure and thoroughly examined by 
 Liebig (Ann. Ch. Pharm. xiv. 133 ; xxxvi. 376). The name aldehyde is an abbrevia- 
 tion of alcohol dehydrogenatum, inasmuch as the compound may be regarded as alcohol 
 deprived of two atoms of hydrogen. 
 
 Formation. 1. In the oxidation of alcohol, either by slow combustion in contact 
 with platinum-black, chromic oxide, &c., or by the action of chromic acid, nitric acid, 
 chlorine water, or a mixture of sulphuric acid and peroxide of manganese (see ALCOHOL, 
 p. 74). 2. When the vapour of alcohol or -ether is passed through a tube heated 
 to dull redness ; also in the slow combustion of ether. 3. In the decomposition of 
 acetate of ethyl, and probably also of other ethylic ethers, by a mixture of sulphuric 
 acid and acid chromate of potassium. 4. By heating ace tal with glacial acetic acid to 
 between 150 and 200 C. for two days. Acetic ether and alcohol are formed at the 
 same time, and on distilling the mixture, aldehyde passes over below 60 : 
 C 6 H 14 2 + C 2 H 4 2 = C 2 H 4 + C 4 H 8 2 + C 2 H 6 O 
 
 Acetal. Acetic Aldehyde. Acetic Alcohol, 
 
 acid. ether. 
 
 also by heating acetal with acetic anhydride : 
 
 C 6 H n Q2 + G 4 H fi 3 = C 2 H'0 + 2C 4 H"0 2 . 
 
 A few drops of liquid are also obtained boiling above 150, and probably consisting of 
 a compound of aldehyde with acetic anhydride (Beilstein, Compt. rend, xlviii. 
 1121). 5. By heating ethyl-sulphuric acid or one of its salts with a mixture of sul- 
 phuric acid and peroxide of manganese. This formation of aldehyde is said to take 
 place. under circumstances which altogether preclude any previous formation of alcohol 
 (Jacquemin and Lies-Bodard, 1'Institut, 1857, p. 407). 6. When hemp-oil is 
 passed through a gun-barrel heated to low redness, a liquid is formed containing a 
 large quantity of aldehyde, together with alhehydic or lampic acid (Hess). 7. By 
 the dry distillation of lactic acid, lactic anhydride, and lactates with weak bases, such 
 as lactate of copper, carbonic oxide being given off at the same time : 
 C 6 H 12 O e = 2C*H 4 + 2CO + 2H 2 0. 
 
 Lactic Aldehyde, 
 
 acid. 
 
 8. Lactic acid and the lactates also yield considerable quantities of aldehyde when dis- 
 tilled with sulphuric acid and peroxide of manganese (Stadeler, Ann. Ch. Pharm. 
 Ixxix. 333). 9. In the decomposition of animal albumin, fibrin, casein, and gelatin by 
 a mixture of sulphuric acid and peroxide of manganese, or bichromate of potassium 
 (Guckelberger), also of vegetable fibrin by sulphuric acid and peroxide ef manganese 
 (Keller). 10. By the dry distillation of a mixture of acetate and formate of calcium 
 in equal numbers of atoms (Limpricht. See ALDEHYDES, p. Ill ; also ACETONES, p. 31). 
 C 2 HCa0 2 + CHCaO 2 = C 2 H 4 O + C0 3 Ca 2 . 
 
 Acetate of Formate of Aldehyde. 
 
 calcium. calcium. 
 
 Preparation. 1. Two pts. of 80 per cent, alcohol are mixed with 3 pts. peroxide of 
 manganese, 3 pts. oil of vitriol and 2 pts. water, and distilled into a receiver kept at a 
 very low temperature. The mixture is gently heated till it begins to froth slightlv, 
 and the distillation is interrupted as soon as the liquid which passes over begins to 
 redden litmus, which it does when the distillate amounts to 3 pts. The distillate, 
 consisting of aldehyde, alcohol, &c., is mixed with an equal weight of chloride of 
 calcium, and distilled (the receiver being constantly kept very cold), till l pt. has 
 passed over, and this distillate is again rectified with an equal weight of chloride of 
 calcium till f pt. has passed over. This last portion is anhydrous, but contains alcohol 
 and certain compound ethers as well as aldehyde. To purify it, 1 vol. is mixed with 2 
 voL. ether, the mixture surrounded with cold water, and dry ammoniacal gas passed into 
 it to saturation ; the gas is absorbed rapidly and with great evolution of heat, and the 
 aldehyde separates out in crystals of aldehyde-ammonia. These crystals are washed 
 three times with absolute ether and dried as above. (Liebig.) 
 
108 ALDEPIYDE. 
 
 2. A mixture of 1 pt. 80 per cent, alcohol and 2 pts. water is saturated with 
 chlorine gas (being kept cool all the while), and the liquid distilled, as soon as it has 
 lost the odour of chlorine, till ~ has passed over. That which distils over afterwards 
 is alcohol, which may be collected in a separate receiver and again treated with chlorine 
 as above. The first distillate is again freed from water by repeated distillation so far 
 as to admit of its being saturated with ammonia as above, and yields a very large 
 crop of crystals. (L i e b i g. ) 
 
 3. One part of alcohol of sp. gr. 0'842 and 1 pt. of bichromate of potassium are in- 
 troduced into a capacious tubulated retort and 1| pt. oil of vitriol admitted by drops 
 through the tubulus. The heat evolved by the chemical action which ensues is suffi- 
 cient to begin the distillation, but towards the end, heat must be applied from without. 
 A large quantity of carbonic acid gas is evolved, and the aldehyde condenses in the 
 well cooled receiver, contaminated with only a small quantity of acetic acid and other 
 substances, so that the distillate may be immediately mixed with ether, and ammoniacal 
 gas passed through it as above (W. and K. Eodgers, J. pr. Chem. xl. 248). The 
 modes of formation 5, 6, and 8, above given, may also be advantageously used for the 
 preparation of aldehyde. 
 
 To obtain the pure anhydrous aldehyde from the aldehyde-ammonia formed by 
 either of these processes, a solution of 2 pts. of the aldehyde-ammonia in 2 pts. water, 
 is distilled in a water-bath at a gentle but increasing heat, with a mixture of 3 pts. 
 sulphuric acid and 4 pts. water, the distillation being interrupted as soon as the water 
 in the bath begins to boil, and the receiver kept as cold as possible, The hydrated 
 aldehyde which passes over is dried by contact with coarse lumps of chloride of cal- 
 cium in a well closed vessel, and then rectified in a water-bath, at a temperature not 
 exceeding 30. 
 
 Properties. Aldehyde is a thin, transparent, colourless liquid, having a pungent 
 suffocating odour. Its specific gravity is 0-80002 at (Kopp) ; 0-80551 at 
 (Pierre). It boils at 20 - 8 when the barometer stands at 760mm. (Kopp); at 
 22, with the barometer at 758-2 mm (Pierre). Vapour-density 1-532 (Liebig) ; (by 
 calculation, 1-520, for a condensation to 2 vol.) It does not redden litmus, even when 
 it is dissolved in water or alcohol. 
 
 Aldehyde may be regarded either as the hydride of acetyl, C 2 H 3 O.H, or as the hy- 
 
 C 2 H 3 ) 
 drate or hydrated oxide of vinyl, TT [ 0. Its chemical reactions may for the most 
 
 part be explained equally well on either hypothesis; but according to the recent 
 observations and calculations of Kopp, the formula C 2 H 3 O.H, is most in accordance 
 with the observed atomic volume of aldehyde, which is between 56-0 and 56-9, the 
 calculated atomic volume being 56-2, as deduced from the first formula, and 5T8 as 
 deduced from the second. (See ATOMIC VOLUME : also Graham's Chemistry, 2nd Ed. 
 vol. ii. p. 581.) Aldehyde is isomeric, but not identical, with the oxide of ethylene, 
 C 2 H 4 .0, recently discovered by Wurtz. 
 
 Aldehyde mixes in all proportions with water, alcohol, and ether. A mixture of 
 1 pt. aldehyde and 3 pts. water boils at 37. Chloride of calcium added to the 
 aqueous solution separates the aldehyde, which then rises to the surface. 
 
 Aldehyde dissolves sulphur and phosphorus, also iodine, forming a brown solution. 
 
 Dry sulphurous acid gas passed into anhydrous aldehyde surrounded with cold 
 water, is rapidly absorbed, 11 pts. of aldehyde absorbing 9 pts. of the gas, with 
 increase of volume. The absorption-coefficient of aldehyde for sulphurous acid gas is 
 1-4 times as great as for alcohol, and 7 times as great as for water. (Greuther and 
 Cartmell, Ann. Ch. Pharm. cxi. 17.) 
 
 Decompositions. 1. Aldehyde is very inflammable, and burns with a blue flame. 
 2. When kept in close vessels, it is often converted into a less volatile liquid, or into 
 two crystalline bodies, which are isomeric modifications of aldehyde (p. 109). 3. In ves- 
 sels containing air, it absorbs oxygen, and is converted into acetic acid ; the action is 
 greatly accelerated by the presence of platinum black. 4. Chlorine-water and nitric 
 acid also convert aldehyde into acetic acid. 5. By strong sulphuric acid, it is thickened 
 and blackened, also by phosphoric anhydride. 6. When an aqueous or alcoholic 
 solution of aldehyde is heated with potash, it becomes yellowish and turbid, and a 
 red-brown resinous mass, the resin of aldehyde, separates on the surface, the liquid at 
 the same time emitting a spirituous and disagreeably pungent odour. The solution is 
 afterwards found to contain formate and acetate of potassium. This is the most 
 characteristic reaction of aldehyde. 7. When vapour of aldehyde is passed over red- 
 hot potash-lime, acetate of potassium is formed and hydrogen evolved : 
 
 C 2 H 4 + KHO = C 2 H 3 K0 2 + 2H. 
 
 8. Potassium (or sodium") acts on aldehyde in the same manner as on alcohol, hydro- 
 gen being evolved and aldehydate of potassium, C'-'H 3 KO, produced. 9. When an 
 
ALDEHYDE. 107 
 
 aqueous solution of aldehyde is heated with oxide or nitrate of silver, mixed with a 
 small quantity of ammonia, the silver is reduced, forming a beautiful specular coating 
 on the side of the vessel, and acetate of silver is formed in the solution. This reaction 
 affords an extremely delicate test for aldehyde. 10. Chlorine gas in contact with alde- 
 hyde, both being dry, decomposes part of the aldehyde, forming chloride of acetyl, which 
 then unites with the undecomposed aldehyde, forming the compound, C 2 H 4 O.C 2 H S OC1. 
 11. When dry hydrochloric acid gas is passed into anhydrous aldehyde surrounded 
 by a freezing mixture, the gas is absorbed, and the liquid separates into two layers, 
 the lower consisting of water saturated with hydrochloric acid, and the upper of oxy- 
 chloride of ethylidene, C 4 H 8 C1 2 (A. Lieben, Compt rend. xlvi. 662) : 
 
 2C 2 H<0 + 2HC1 = C 4 H 8 CPO + H 2 0. 
 
 According to Geuther and Cartmell (Ann. Ch. Pharm. cxii. 13 ; Proc. Eoy. Soc. 
 x. 110) the first product of the action is the body, C S H 12 C1 2 2 , which, when gently 
 heated in an atmosphere of carbonic acid, splits up into aldehyde, C 2 H 4 0, and 
 C 4 H 8 C1 2 0. rphe Com p 0un( i C 6 H 12 C1 2 2 , may be regarded as a triple molecule of alde- 
 hyde (C 6 H 12 3 ), having one atom O replaced by Cl 2 . 12. Aldehyde mixed with twice 
 its bulk of absolute alcohol, and saturated in the cold with hydrochloric acid gas, 
 yields the compound C 4 IPC10, which, when treated with ethylate of sodium, forms 
 acetal (p. 3). 13. With pentachloride of phosphorus, aldehyde yields chloride of 
 ethylidene, C 2 H 4 C1 2 , and with pentabromide of phosphorus it yields bromide of ethyli- 
 dene, C 2 H 4 Br 2 , which is converted by ethylate of sodium into acetal (p. 4). 14. Ckloro- 
 carbonic oxide (phosgene gas) converts aldehyde into chloride of vinyl, C 2 H 3 C1, with 
 evolution of hydrochloric acid and carbonic anhydride. (Harnitz Harnitzky, Ann. 
 Ch. Pharm. cxi. 192.) 
 
 C 2 H 4 + COC1 2 = C 2 H 3 C1 + HC1 + CO 2 . 
 
 15. Hydriodic acid gas appears to act upon aldehyde in the same manner as hydro- 
 chloric acid, but the product is very unstable. 16. When aqueous aldehyde is satu- 
 rated with hydrosidphuric acid gas, a viscid oil is formed, consisting of hydrosul- 
 phate of acetyl-mercaptan : C 12 H 26 S 7 = SH 2 .6C 2 H 4 S. On treating this oil with strong 
 hydrochloric or sulphuric acid, hydrosulphuric acid escapes, and a white crystalline 
 mass remains, consisting of acetyl-mercaptan, C 2 H 4 S, a compound related to aldehyde, 
 in the same manner as ethyl-mercaptan, C 2 H 6 S, to alcohol. 17. Cyanic acid vapour 
 evolved from cyanuric acid is quietly absorbed by anhydrous aldehyde at ; but 
 even at ordinary temperatures the mixture becomes heated, gives off carbonic anhydride, 
 and ultimately froths up and solidifies into a mass consisting of trigenic acid, C'H 7 N 3 0-, 
 together with small quantities of cyamelide, aldehyde-ammonia, and other products 
 (Liebig and Wohler): 
 
 C 2 H 4 + 3CNHO = C 4 H 7 N'0 2 -f CO 2 . 
 
 ALDEHYDATES. Aldehyde may be regarded as a monobasic acid, inasmuch as it 
 contains one atom of hydrogen replaceable by metals. Thus, when potassium is 
 gently heated with aldehyde, hydrogen is evolved, and aldehydate of potassium, 
 C 2 H 3 KO, produced : and by evaporation in vacuo this salt may be obtained in the 
 solid state. Aldehydate of silver, C 2 H 3 AgO, is produced when oxide of silver is 
 heated with aldehyde and ammonia. The most important of these salts is the am- 
 monium-salt : 
 
 Aldehydate of Ammonium, Aldehyde-ammonia, Acetyl-ammonium, C 2 H 4 O.NH 3 = 
 C 2 H 3 O.NH 4 , or Oxide of Vinyl and Ammonium, C 2 H 3 .NH 4 .O. Ammoniacal gas 
 passed into pure aldehyde combines with it, giving off heat, and forming a 'white 
 crystalline mass. If the aldehyde be previously mixed with ether, the compound 
 separates in distinct crystals ; the finest are obtained by mixing a concentrated 
 alcoholic solution of aldehyde-ammonia with ether (Liebig). The crystals are acute 
 rhombohedrons with terminal edges of about 85, often truncated with the faces of 
 another rhombohedron (Gr. Kose) ; they are transparent, colourless, shining, strongly 
 refractive, of the hardness of common sugar, and very friable. The compound melts 
 between 70 and 80 C., and distils unaltered at 100. In the state of vapour or in 
 aqueous solution, it reddens turmeric paper. Its odour is ammoniacal, but has like- 
 wise the character of turpentine (Liebig). It dissolves very easily in water, less 
 easily in alcohol and ether. 
 
 Aldehyde- ammonia is very inflammable. In contact with the air, especially if also 
 exposed to light, it becomes yellow, and acquires an odour resembling that of burnt 
 animal substances. By distillation it may again be obtained in the colourless state, 
 and leaves a brown residue, which is soluble in water, and contains acetate of am- 
 monium and another ammoniacal salt. Even the weaker acids, such as acetic acid, 
 separate the aldehyde from the compound. Sulphuric acid and potash act upon it in 
 
108 ALDEHYDE. 
 
 the same manner as upon aldehyde. Its aqueous solution, digested with oxide of 
 silver, reduces part of this oxide and dissolves the rest, forming aldehydate and acetate 
 of silver mixed with ammonia, from which the oxide of silver is precipitated by baryta- 
 water, and reduced when the liquid is heated, while acetate of barium remains in 
 solution. 
 
 Aldehyde-ammonia treated with hydrosulphuric acid yields thialdine, C 6 H 13 NS 2 : 
 
 3(C 2 H 3 O.NH 4 ) + 3H 2 S = C 6 H 13 NS 2 + (NH 4 ) 2 S + 3H 2 0. 
 
 Similarly, with hydroselenic acid, it yields selenaldine, C 6 H' 3 NSe 8 . With bisulphide 
 of carbon it forms carbothialdine : 
 
 2(C 2 H 3 O.NH 4 ) + CS 2 = C 5 H 10 N 2 S 2 + 2H 2 
 
 Aldehyde-ammonia heated with hydrocyanic and hydrochloric acids yields alanine : 
 C 2 H 4 O.NH 3 + CNH + H 2 + HC1 = C 3 H 7 N0 2 + NH 4 C1. 
 
 Aldehyde- Hydro- Alanine. 
 
 ammonia. cyanic 
 
 acid. 
 
 But when a mixture of aldehyde-ammonia and hydrocyanic acid, with sufficient hydro- 
 chloric acid to give it a distinct acid reaction, is left to itself for some time, in a closed 
 vessel, especially in sunshine, colourless needle-shaped crystals are formed, consisting 
 of hydrocyanaldine, C 9 H 12 N 4 : 
 
 3(C 2 H 4 O.NH 3 ) + 3CNH + 2HC1 = C 9 H 12 N 4 + 2NH 4 C1 + 3H 2 0. 
 Aldehyde-ammonia heated in a sealed tube to 120 C. is decomposed, and yields two 
 layers of liquid, the upper consisting chiefly of aqueous ammonia, with small quanti- 
 ties of other volatile bases, while the lower, which remains behind on distilling at 
 200, contains a substance which has the composition C 10 H 13 NO, and may be regarded 
 as an aldehydate of tetravinylium : = C 2 H 3 O.N(C 2 H 3 ) 4 . Its formation is represented 
 by the equation : 
 
 6(C 2 H 3 O.NH 4 ) = C 10 H 15 NO + 4KH 3 + 4H 2 0. 
 
 By treating this compound with baryta-water, the group C 2 H 3 is replaced by HO. 
 and hydrate of tetravinylium is formed. 
 
 C ? H 3 O.N(C 2 H 3 ) 4 + BaHO = C 2 H 3 O.Ba + N(C 2 H 3 ) 4 .H.O. 
 
 (Babo, J. pr. Chem. Ixxii. 88 ; Chem. Gaz. 1858, 136.) 
 
 Concentrated aqueous solutions of aldehyde-ammonia and nitrate of silver yield, 
 when mixed, a fine-grained white precipitate, probably consisting of N0 8 Ag. 
 2(C 2 H 3 O.NH 4 ). It dissolves very sparingly in alcohol, easily in water. 
 
 Sulphite of Aldehyde-ammonia, or Sulphite of Vinyl-ammonium, C 2 H 3 (NH 4 )O.S0 2 = 
 (C-H 3 .NH 4 ).S0 3 . Sulphurous acid gas passed into a solution of aldehyde-ammonia in 
 absolute alcohol is rapidly absorbed ; and if the liquid be kept cool, sulphite of alde- 
 hyde-ammonia is deposited in small white prisms, which may be washed with alcohol 
 and dried in vacuo. This compound is isomeric with taurin, C 2 H 7 N0 3 S a substance 
 produced by the metamorphosis of a sulphur-acid contained in the bile but possesses 
 very different properties. It is soluble in water and in aqueous alcohol, very 
 sparingly in absolute alcohol. The crystals decompose slowly in the air at ordinary 
 temperatures, turn brown and lose weight at 100^, and are completely decomposed at 
 higher temperatures, leaving a spongy carbonaceous residue. Acids decompose them, 
 liberating aldehyde and sulphurous anhydride. When strongly heated with potash- 
 lime, they give off ethylamine (Gossmann, Ann. Ch. Pharm. xci. 122), or rather 
 perhaps dimethylamine : 
 
 C'IF.NmSO' + KEO = C 2 H 7 N + S0 4 .HK. 
 
 COMPOUND OF ALDEHYDE WITH ACETIC ANHYDEIDE, C 6 H 10 4 = C 4 H 6 3 .C 2 H 4 0. 
 When 1 at. acetic anhydride and 1 at. pure aldehyde are heated together in a sealed 
 tube to 180 C. for about 12 hours, they unite and form a liquid compound which may be 
 freed from unaltered aldehyde and acetic anhydride by fractional distillation, further 
 purified by washing the portion which passes over above 140 with hot water, and dehy- 
 drated over chloride of calcium. It then boils at 168. It has an alliaceous odour and 
 slight acid reaction, probably arising from decomposition during distillation. Heated 
 with hydrate of potassium, it yields acetate of potassium, giving off the peculiar odour of 
 aldehyde when similarly treated. This reaction distinguishes the compound from Wurtz's 
 acetate of ethylene (acetate of glycol), C 2 II 4 (C 2 H :| 0)*.0'' 8 with which it is isomeric: for 
 that compound heated with caustic alkalis, yields hydrate of ethylene (glycol), with- 
 out any odour of aldehyde. (Geuther, Ann. Ch. Pharm. cvi. 249.) 
 
 Aldehyde appears to form similar compounds with benzole and sc.ccinic anhydrides. 
 
ALDEHYDE. 109 
 
 COMPOUND OF ALDEHYDE WITH CHLORIDE OF ACETYL, C 4 H 7 C10 2 = C 2 H 4 O.C 2 H a OCl. 
 Chloride of acetyl and aldehyde heated together to 100 for three hours in a 
 sealed tube, unite and form a liquid which distils completely between 90 and 140 C. 
 and yields by fractional distillation a considerable quantity of liquid, boiling between 
 120 and 124. This liquid is lighter than water ; is very slowly decomposed by cold 
 water, more quickly by hot water ; and dissolves easily in dilute potash, forming 
 chloride and- acetate of potassium, and yielding free aldehyde which is partly resinised 
 by the potash. Moist oxide of silver also decomposes it, forming chloride and acetate 
 of silver. (Maxwell Simpson, Compt.-rend. xlvii. 174.) 
 
 The same compound is produced, according to Wurtz (Ann. Ch. Phys. [3] xliv. 58), 
 together with chloride of acetyl, by introducing perfectly dry aldehyde into a large 
 vessel filled with dry chlorine. Its formation is due to the union of the chloride of 
 acetyl first produced with the remaining aldehyde (compare p. 106). Wurtz, how- 
 ever, regards it as a double molecule of aldehyde (C 4 H 8 2 ), having 1 at. H replaced by 
 chlorine. 
 
 MODIFICATIONS OF ALDEHYDE. Aldehyde is susceptible of four isomeric modifica- 
 tions, two liquid and two solid. 
 
 . Liquid 'modifications. 1. Pure aldehyde sealed up in a tube changes in the 
 course of a few weeks into a liquid, which has a pleasant ethereal odour, boils at about 
 81, and no -longer forms a resin with potash; it may be exposed to the air without 
 oxidising, and floats on water without mixing. (Lie big) 
 
 2. Pure aldehyde mixed with about half its bulk of water and a trace of sulphuric 
 or nitric acid, and cooled to C., changes into a liquid which is no longer miscible with 
 water, and after being purified by agitation with water, and rectification over chlo- 
 ride of calcium, boils at 125. It has a peculiar aromatic burning taste, and is 
 soluble in alcohol and ether, sparingly also in water. Its vapour-density is 4-583, 
 which for a condensation to 2 volumes, corresponds to the formula C 6 H 12 3 . When 
 left to itself, or in contact with water, it readily changes into an acid, and then becomes 
 miscible with water ; occasionally also crystals separate from it at the same time. 
 When heated with a small quantity of sulphuric or nitric acid, it is converted into 
 ordinary aldehyde. (Weidenbusch, Ann. Ch. Pharm. Ixvi. 155.) 
 
 b. Solid modifications. 1. Solid and fusible Elaldehyde. Anhydrous aldehyde, en- 
 closed in a tube, together with pieces of chloride of calcium, for two months in winter, 
 yielded long transparent prisms, which, however, disappeared again after a fortnight, 
 so completely that not a trace of them could be perceived in the liquid. These crys- 
 tals melt at + 2 C., forming a liquid which solidifies at 0, and boils at 94, giving off 
 a vapour whose density is 4-5157. In the fused state, this substance has an ethereal 
 odour ; more agreeable and less pungent than that of aldehyde ; its taste is some- 
 what burning. Its burns with a blue flame ; its vapour passed through a red-hot 
 tube yields a combustible gaseous mixture, and a small quantity of a liquid having 
 an empyreumatic odour. Oil of vitriol blackens the crystals slowly in the cold, imme- 
 diately when heated. The crystals may be heated with potash-ley for some time with- 
 out becoming coloured, and solidify again on the surface as the liquid cools. When 
 heated with aqueous nitrate of silver, they throw down the silver in the form of a 
 grey powder, not as a specular coating. When dissolved in ether, they do not absorb 
 ammoniacal gas but remain unaltered. ' (Fehling, Ann. Ch. Pharm. xxvii. 319.) 
 
 Geuther and Cartmell (Ann. Ch. Pharm. cxi. 16) have obtained a similar modi- 
 tion, by saturating common aldehyde with sulphurous acid gas, dissolving the result- 
 ing liquid in water, saturating the acid with chalk, distilling, and treating the dis- 
 tillate with potash, which separates the remaining common aldehyde in the resinous 
 form, and leaves the modified aldehyde in the form of a clear liquid, which boils at 
 124 C., like the modification obtained by Weidenbusch, and solidifies at 10, starting 
 into crystals which also begin to melt at 10. 
 
 2. Solid and infusible Mctaldehyde. Anhydrous aldehyde kept for some time in a 
 sealed tube or well stoppered bottle, frequently deposits transparent, colourless, four- 
 sided prisms, which traverse the whole liquid like a network. The crystals remain 
 solid at 100 C., but at a stronger heat sublime undecomposed, in the form of transpa- 
 rent, colourless, shining, rather hard needles, which are easily pulverised, inodorous, 
 combustible, scarcely at all soluble in water, but easily soluble in alcohol and ether 
 (Liebig). Fehling, by exposing pure aldehyde to the cold of winter for several 
 weeks, once obtained the same crystals, mixed, however, with a larger quantity of 
 the crystals b. They are hard and easy to pulverise; at 120 they sublime without 
 previous fusion. When they are suffered to evaporate in the air, the vapour condenses 
 in fine snowy flakes (Liebig). Heated for some time to 180 in sealed tubes 
 they are reconverted into ordinary aldehyde. (G-euther, Ann. Ch. Pharm. cvi. 252.) 
 
 ALDEHYDE-RESIN. A resinous body obtained by heating aldehyde with potash, either 
 in aqueous or in alcoholic solution, especially the latter. It is also formed in solutions 
 
110 
 
 ALDEHYDES. 
 
 of the alkalis in alcohol, and in acetal, when kept for a long time. According to 
 Weidenbuseh (Ann. Ch. Pharm. Ixvi. 153) it is a substance of a fiery orange colour 
 which is reduced by drying at 100, to a powder, having a paler tint. It dissolves in 
 alcohol and ether, sparingly in water, scarcely at all in alkalis, partially in strong 
 sulphuric acid, from which it is precipitated by water. When purified as completely 
 as possible, it contains 76'4 per cent, of carbon, and 8'0 per cent, of hydrogen: its 
 formation is accompanied by that of acetic, formic and acetylou-i [?] acid; at the 
 same time a pungent odour is evolved, proceeding from a peculiar substance which 
 adheres obstinately to the resin. This substance is oily and volatile when first pro- 
 duced, but soon thickens, even when alone and still more quickly under the influence 
 of nitric acid, and is converted into a golden-yellow, viscid resin, which smells like 
 cinnamon, dissolves in alcohol and ether, and sparingly in water, and is different from 
 the true aldehyde-resin. 
 
 AIiDEHYDES. A class of organic compounds intermediate between alcohols 
 and acids. They are derived from alcohols by abstraction of 2 atoms of hydrogen, 
 and are converted into acids by addition of 1 atom of oxygen : thus in the fatty acid 
 
 OH 8n O, and OH 8 + = C"H 2n 2 
 
 Alcohol. 
 
 Aldehyde. 
 
 Aldehyde. 
 
 Acid. 
 
 Aldehydes may be regard d as derivatives : 1, Of a molecule of hydrogen HH, half 
 the hydrogen being replaced by an oxygen-radicle : e. g. benzoic aldehyde or bitter- 
 almond oil, C 7 H 6 = C'IPO.H. 2. Of a molecule of water, half the hydrogen being 
 
 replaced by a monatomic hydrocarbon, e.g. benzoic aldehyde = f O; acetic alde- 
 hyde = TT [ 0. 3. Of a molecule of water, in which the whole of the hydrogen is 
 
 replaced by a diatomic hydrocarbon: e.g. acetic aldehyde = (C 2 H 4 .) // 0. According to 
 this last view, which is strongly corroborated by the action of sulphuric acid and 
 chloride of zinc upon glycol (p. 102), the aldehydes are isomeric with the ethers or an- 
 hydrides of the diatomic alcohols, and are related to them in the same manner as the 
 dibasic anhydrides to the dibasic acids ; thus 
 
 Type H 4 2 Type H 2 
 
 Sulphuric acid 
 
 Sulphuric anhydride SO 2 . 
 
 Glycol H 2 [ 2 Aidekyd 6 C 2 H 4 .0. 
 
 The following are the aldehydes at present known. 
 
 1. Aldehydes of the form C n H 2n O = ^^"''JO = C 2n H 2n - ! O.H. 
 
 Acetic aldehyde 
 Propionic 
 Butyric 
 Valeric 
 CEnanthylic 
 
 C 2 H 4 
 C 3 H 6 
 C 4 H 8 
 C 5 H 10 
 C 7 H 14 
 
 2. Aldehyde of the form OH 2 - 2 = 
 Acrylic aldehyde, or Acrolein, C 3 H 4 0. 
 
 3. Aldehyde of the form OH 2 -0 = 
 Campholic aldehyde, or Camphor, C IO H 16 0. 
 
 4. Aldehydes of the form C"E>- 8 
 
 Benzoic aldehyde, or Bitter-almond oil, C 7 H 6 0. 
 Cuminic aldehyde, or Oil of Cumin, C 8 H 8 0. 
 
 6. Aldehyde of the form C"E>- 10 = 
 Cinnamic aldehyde, or Oil of Cinnamon, C 9 H 8 0. 
 
 6. Aldehydes of the form C"H>- 8 2 = Cn 
 
 Salicylic aldehyde, or Salicylous acid, C 7 H 6 2 . 
 Anisylic aldehyde, or Anisylous acid, C 8 H 8 0*. 
 
 Caprylic aldehyde [?]. 
 Enodic . 
 
 Laurie . 
 
 Palmitic . 
 
 C 9 H 16 O 
 C n H 22 
 C 12 H 24 
 C 16 H 32 
 
 C 2 H 2 --O.H. 
 
 = C"H 2 - 5 O.H 
 
 = OH^-'O.H. 
 
 ' or C n H ?n -O.H. 
 
 , or C-H 2 "- 9 8 .H. 
 
ALDEHYDES. Ill 
 
 The aldehydes corresponding to known alcohols may all be formed from those 
 alcohols by oxidation, either by exposure to the air in contact with platinum-black, or 
 by distillation with a mixture of dilute sulphuric acid and peroxide of manganese or 
 acid chromate of potassium. Aldehydes may also be prepared from the corresponding 
 acids by a general process, viz. by distilling a mixture of the barium-salt of the acid 
 with an equivalent quantity of formate of barium, thus : 
 
 C 7 H 5 
 
 (Limpricht, Ann. Ch. Pharm. xcvii. 368; Piria, Ann. Ch. Phys. [3] xlviii. 113). 
 This process is a particular case of Williamson's method of producing compound ace- 
 tones (p. 31). 
 
 Several aldehydes, as benzoic, acetic, propionic, butyric, &c. are produced by the 
 distillation of albumin, fibrin, casein, and gelatin with peroxide of manganese and 
 sulphuric acid. Some are formed in the destructive distillation of organic acids, as 
 acetic aldehyde from lactic acid, cenanthylic aldehyde from ricinolic acid. Caprylic 
 aldehyde is said by some chemists to be produced (together with the corresponding 
 alcohol), by distilling ricinolic acid with excess of potash. According to Bouis 
 (Compt. rend. xli. 603), a new acid, C 10 H 18 2 , is formed at the same time : 
 
 C 18 H 34 3 = C 8 H 16 + C 10 H 18 0' 2 . 
 
 Ricinolic Caprylic 
 acid. aldehyde. 
 
 But according to Malaguti (Cimeuto, iv. 401), the acid formed is sebacic acid 
 thus: 
 
 C 19 H 34 3 + 20 = C 8 H 16 + C 10 H 18 4 
 
 Caprylic Sebacic 
 
 aldehyde. acid. 
 
 This decomposition is supposed to take place simultaneously with that by which 
 octylic (capryHc) alcohol is produced (p. 97). The aldehyde might indeed be pro- 
 duced by oxidation of the alcohol. According to Stadeler, on the other hand ( J. pr. 
 Chem. Ixxxiii. 241), the product C 8 H 16 thus formed is not caprylic aldehyde, but 
 methyl-cenanthyl, CH 3 .C 7 H 13 0, a body isomeric with it (p. 97). 
 
 Many aldehydes are obtained directly from plants, either existing ready formed in 
 the plants, or being given off as volatile oils on distilling the plants with water. Thus, 
 benzoic aldehyde constitutes the essential part of bitter-almond oil, cinnamic alde- 
 hyde of cinnamon oil, cuminic aldehyde of Roman cumin oil, and salicylic aldehyde 
 or salicylous acid, of oil of spiraea. Oil of rue consists principally of euodic aldehyde, 
 mixed with a small quantity of lauric aldehyde (C. Of. Williams , Proc. Koy. Soc. ix. 
 167). It was formerly supposed to be capric aldehyde. Benzoic aldehyde is also pro- 
 duced by the action of nascent hydrogen (evolved by the action of zinc on hydrochlo- 
 ric acid) on cyanide of benzoyl, hydrocyanic being formed at the same time : 
 
 C 7 H 5 O.Cy + HH = C'IPO.H + CyH. 
 
 This mode of formation corresponds with the representation of aldehydes as hydrides 
 of acid radicles. 
 
 All the known aldehydes (except palmitic aldehyde, which is a fatty solid) are 
 liquids, which volatilise without decomposition. They are very prone to oxidation, 
 being converted into acids more or less quickly by mere exposure to the air. In con- 
 sequence of this tendency to oxidation, they easily reduce the oxides of the noble 
 metals (see p. 106). Many aldehydes are converted by hydrate of potassium, espe- 
 cially in alcoholic solution, into the corresponding alcohols, and the potassium-salt of 
 the corresponding acid : thus, with bitter almond oil : 
 
 2C T H 6 + KHO = C'H 8 + C'H 5 K0 2 
 
 Benzyl- Benzoate of 
 alcohol. potassium. 
 
 Cuminic aldehyde and anisylic aldehyde are decomposed in like manner. The al- 
 dehydes of the first series (corresponding to the fatty acids) and acrylic aldehyde, are 
 not decomposed in this manner : acetic aldehyde treated with potash yields acetate 
 and formate of potassium and a brown resinous mass. 
 
 All aldehydes form definite, and for the most part crystalline, compounds with the 
 acid sulphites of the alkali-metals, e. g. bitter-almond oil with acid sulphite of sodium, 
 
112 ALDEHYDES. 
 
 C 7 H G O.SO s NaH ^aj 808 + H2 == NaC 7 II 5 | 2 + H2 ' These com P luld3 
 are for the most part soluble in water and alcohol, but insoluble in saturated solutions 
 of the alkalj.no bisulphites. Hence by shaking a liquid containing an aldehyde with 
 excess of such a saturated solution, the aldehyde may be completely separated in the form 
 of a crystalline compound. This is an excellent method of purifying those volatile oils 
 which have the constitution of aldehydes. The acid sulphites of potassium and sodium 
 are, generally speaking, the best adapted for this purpose, as the compounds which they 
 form with the aldehydes are much less soluble in the solution of the sulphite than the 
 corresponding ammonium-compounds, and therefore crystallise more readily. From 
 all these compounds, the aldehyde may be set free by the action of the stronger acids, 
 or by neutralisation with an alkaline carbonate, and may then be obtained in the pure 
 state by distillation. 
 
 The aldehydes of the first series combine with ammonia, forming crystalline com- 
 pounds like aldehyde-ammonia, C 2 H 4 O.NH 3 , (p. 106), and valeral-ammonia, C 5 H 10 O.NH 9 . 
 These compounds treated with sulphuretted hydrogen yield sulphur-bases, like thial- 
 dine, C 6 H 13 NS*, and valeraldine, C 15 H 31 NS 2 , thus : 
 
 3(C S H 10 O.NH 3 ) + 3H 2 S = C I5 H 31 NS 8 + (NH 4 ) 2 S + 3H 2 0. 
 
 Heated with hydrocyanic and hydrochloric acids, they yield bases similar to the last, 
 but containing oxygen in place of sulphur : e. g. : 
 
 C 5 H'".O.NH 3 + CNH + C1H + H-'O = C^'NO 2 + NH 4 C1. 
 
 Leucine. 
 
 Acrylic aldehyde appears also to combine directly with ammonia, forming a white 
 amorphous compound. 
 
 The remaining aldehydes yield with ammonia peculiar amides called hydramides, 
 the formation of which is attended with elimination of 3 atoms of water, e. g. 
 
 3(C 7 H 6 .0) + N 2 H 6 = N 2 (C 7 H) 3 + 3H 2 
 
 Hydrobenza- 
 mide. 
 
 N 2 H 6 = K 2 (C 7 H 6 0) 3 + 3H 2 
 
 Salicylic Salhydramide. 
 
 aldehyde. 
 
 Aldehydes also combine with anhydrous acids (anhydrides), forming compounds 
 which are isomeric, but not identical with the diacid glycol-ethers. Thus acetic alde- 
 hyde unites with anhydrous acetic acid, forming the compound, OH 4 O.C 4 H 6 3 , isomeric 
 with acetate of ethylene, C 2 H 4 .(C 2 H 3 0) 2 .0 2 ; also with anhydrous benzoic and succinic 
 acids. Valeral forms with anhydrous acetic, and benzoic acids, the compounds 
 C 5 H'O.C 4 H 6 3 and C 5 H 10 O.C 14 H0 3 , isomeric with acetate and benzoate of amylene, 
 C 5 H'.(C 2 H 3 0) 2 .0 2 and C S H'.(C 7 H 5 0) 2 .O 2 . These compounds heated with caustic 
 alkalis yield acetates, benzoates, &c., of the alkali-metals, and reproduce the original 
 aldehydes, whereas the acetates, benzoates of ethylene, amylene, &c., under the same 
 circumstances, yield glycols, or hydrates of ethylene, amylene, &c. (Greuther, Ann. 
 Oh. Pharm. cvi. 249 ; Ghithrie u. Kolbe, ibid. cix. 296.) 
 
 The calcium and barium-salts of certain monobasic organic acids, butyric and valeric 
 acids, for example, yield by dry distillation, together with acetones (p. 31), compounds 
 isomeric with the aldehydes, but distinguished from them by not combining with am- 
 monia: these compounds are called butyral, valeral, &c. (Chancel, J. Pharm. [3] 
 vii. 143; Limpricht, Ann. Ch. Pharm. xc, 111.) 
 
 Many of the aldehydes are susceptible of polymeric transformations. Acetic alde- 
 hyde exhibits three or four such modifications (p. 108) ; and benzoic aldehyde is very 
 apt to pass into the solid substance benzoin, C 14 H 12 8 . 
 
 The acetones or ketones are aldehydes in which the basic atom of hydrogen is re- 
 placed by an alcohol-radicle, thus : 
 
 Aceto^e 
 
 Valeracetone - . C,PO 
 
 AXiDXDE. The generic name applied by L. Grmelin, in his Handbook, to the alde- 
 hydes, the latter term being by him restricted to acetic aldehyde. In Gmelin's system, 
 the term includes several organic anhydrides and other compounds not generally re- 
 garded as aldehydes. (Handb. vii. 192.) 
 
ALEMBIC ALIZARIN. 1 1 3 
 
 ALEMBIC. An apparatus for distillation, much used by the older chemists. ! t 
 consists of a body a, to which' is adapted a head b, of conical shape, and having its 
 external circumference or base depressed lower than . . 
 
 the neck, so that the vapours which rise and are con- ^ "' ' 
 
 densed against the sides, run down into the circular 
 channel formed by its depressed part, whence they 
 pass through the nose or beak c, into the receiver d. 
 The alembic is now scarcely used in the laboratory, 
 being superseded by the retort, which is simpler and 
 less expensive. Nevertheless, the alembic has its 
 advantages. In particular the residues of distilla- 
 tions may be easily cleared out of the body a ; and in 
 experiments of sublimation, the head is very con- 
 venient to receive the dry products, while the more 
 volatile portions pass over into the receiver. Glass 
 
 alembics are now used in some manufactories of sulphuric acid for effecting the final 
 concentration of the acid. 
 
 AXiEMBROTH-SAXiTr A name given by the alchemists to one of the double 
 chlorides of mercury and ammonium, 2(NH 4 Cl.HgCl) + H 2 0, also called Salt of wisdom. 
 
 ALEXANDRITE. (See CHRYSOBERYL.) 
 
 AXi&AROTH (Powder of). The alchemical name for the oxychloride of anti- 
 mony, produced by throwing the chloride (butter of antimony) into water. 
 
 . A hydrated silicate of alumina, occurring in New Jersey, and crys- 
 tallising, sometimes in right, sometimes in oblique prisms. The following analyses of 
 it have been given by Hunt and Crossley : 
 
 Silica . . . . . . . 52-16 52-00 
 
 Alumina ...... 26 '08 25 -42 
 
 Sesquioxide of Iron .... 1*94 1'54 
 
 Magnesia . . . . . 1-21 5'39 
 
 Potash ...... 10-69 10'38 
 
 Water ....... 7 '92 5-27 
 
 100 100-00 
 
 ALIMENTARY* SUBSTANCES. (See NUTRITION.) 
 
 AXiXSItXXNT, An acrid, bitter extract, probably a mixture of several compounds, 
 obtained from the water-plaintain (Alisma Plantago} (Jach, Kepert. Pharm. iv. 174 ; 
 vi. 246.) 
 
 AXiXXXA-CAMPHOR. A crystalline substance, sometimes deposited on the 
 inner surface of the bark oiAlixia aromatica. The crystals are white and capillary, with 
 a slight aromatic taste and the agreeable odour of the plant. They sublime un decom- 
 posed between 70 and 80C., but at higher temperatures they melt and form a brown 
 substance. They are insoluble in cold, but soluble in warm water, forming a neutral 
 solution, which deposits the crystals unaltered ; so likewise does the distillate obtained 
 from this solution. They dissolve readily in alcohol of 80 per cent., in ether, oil of 
 turpentine, caustic potash, carbonate of potassium, and caustic ammonia. Nitric acid 
 of sp. gr. 1-2 does not dissolve, but merely colours them yellow. (Handwork d. 
 Chem. i. 431.) 
 
 AXiZZARXC ACID. Obtained by Schunck by the action of nitric acid on alizarin, 
 and shown by Wolff and Strecker to be identical with Laurent's phthalic acid (which 
 see.) 
 
 AX.XZARXH-. C IO H 8 J + 21^0 [or C"H 6 O e + HO]. Uzaric acid, A. red colour- 
 ing matter obtained from madder. It was first prepared by Robiquet and Colin 
 (Ann. Ch. Phys. [2] xxxiv. 225), who obtained it by digesting pounded madder with 
 water at 15 or 20 C., exhausting the gelatinous extract thereby obtained with alcohol, 
 and treating the alcoholic solution, after concentration, with dilute sulphuric acid. A pre- 
 cipitate was thereby obtained, which, when washed, dried, and sublimed, yielded alizarin 
 in long, brilliant needles, having the red colour of native chromate of lead. Alizarin is 
 identical with Runge's madder-red ( J. pr. Chem. v. 362), and with the somewhat impure 
 matiere colorante rouge, obtained from madder by Per soz andGaultier de Claubry 
 (Ann. Ch. Phys. [2] xlviii. 69), and has been prepared in the pure state by Schunck 
 (Ann. Ch. Pharm. Ixvi. 174), by Debus (ibid. Ixv. 351), and by Wolff and Strecker 
 (ibid. Ixxv. 1). It appears not to exist ready formed in madder, but to be produce^ 
 by the decomposition of rubian and ruberythric acid. ^See MADDER.) 
 
 VOL. I. I 
 
114 ALIZARIN. 
 
 Preparation according to Wolff and StrecJccr. Madder is exhausted with boiling 
 water; the decoction is precipitated by sulphuric acid ; and the washed precipitate 
 while yet moist, is boiled with a concentrated solution of alumina in hydrochloric acid, 
 whiclTdissolves the colouring matters, and leaves a dark brown residue. The solution 
 mixed with hydrochloric acid deposits red flakes, consisting of alizarin, more or less 
 contaminated with purpurin and resinous matters. This precipitate is dissolved in 
 alcohol, or in dilute ammonia, and the solution is treated with hydrate of alumina, 
 which unites with the colouring matters ; and the alumina-compound thus formed is 
 boiled with carbonate of soda, which dissolves the purpurin and leaves the alizarin in 
 combination with the alumina. Lastly, this compound, after being freed from resinous 
 matters by digestion in ether, is decomposed by hot hydrochloric acid which dissolves 
 the alumina ; and the alizarin thus separated is washed, dried by simple exposure to 
 the air, and purified by repeated crystallisation from alcohol. 
 
 According to Schwartz (Bull, dela Soc. industr. de Mulhouse, 1856, No. 135), the 
 purest alizarin is obtained by subliming on paper an alcoholic extract of madder having 
 at least 35 times the colouring power of the root itself. According to Plessy and 
 Schiitzenberger (Compt. rend, xliii. 167), when an extract of madder prepared with 
 wood-spirit, is triturated with a tenfold quantity of water, and heated to 250 in a 
 closed vessel, the water on cooling becomes filled with crystals of alizarin ; and the 
 fused extractive mass remaining at the bottom of the vessel, yields, when again treated 
 in the same manner, an additional quantity of very pure alizarin. 
 
 Anderson, by treating opianic acid (0 10 H 10 5 = alizarin + 2H 2 0) with sulphuric 
 acid, obtained a colouring matter (probably alizarin), which yielded all the madder 
 colours with alumina and iron mordants. (Edinb. Phil. Trans, xxi. 1, 204.) 
 
 Alizarin in the anhydrous state forms red prisms, inclining more or less to yellow, 
 according to the size of the crystals. It combines with 2 at. water, forming scaly 
 crystals like mosaic gold. These crystals give off their water at 100 C., becoming 
 opaque and of a darker colour. At 215 the compound sublimes, yielding a crystalline 
 sublimate of the same composition as alizarin dried at 100 ; nevertheless a consider- 
 able quantity of charcoal is always left behind. 
 
 The following are the mean results of the analyses of alizarin dried between 100 
 and 120 or sublimed : 
 
 IOC 
 6H 
 3 O 
 
 Calculation. 
 
 
 Robiquet. 
 
 Schunck. 
 
 Debus. 
 
 Rochled^r. 
 
 . 120 
 
 68-96 
 
 6972 
 
 69-4 
 
 68-96 
 
 67-93 
 
 6 
 
 3-45 
 
 3-74 
 
 4-0 
 
 3-78 
 
 3-77 
 
 . 48 
 
 27-59 
 
 26-54 
 
 26-6 
 
 27-26 
 
 28-30 
 
 174 
 
 100-00 
 
 100-00 
 
 100-0 
 
 100-00 
 
 100-00 
 
 C 10 H 6 3 
 
 Shnnck assigns to crystallised alizarin the formula C I4 // 5 4 -r 1HO According to the formula 
 C10H6Q 3 , alizarin is clo-ely related to Laurent's chloronapthalic acid, C 10 H 5 C1O 3 . The latter, when 
 boiled with nitric acid, yields phthalic and oxalic acid, like alizarin (vid. inf.). 
 
 Alizarin dissolves but sparingly in water, even at the boiling heat ; but according to 
 Plessy and Schiitzenberger (loc. cit.} its solubility is much increased by heating to 
 higher temperatures in close vessels, 100 pts. of water dissolve 0'034 pt. of alizarin 
 at 100 C. ; 0-035 at 150 ; 0'82 at 200 ; 170 at 225 ; and 3'16 pts. at 250. 
 
 Alcohol and ether dissolve it, forming yellow solutions. It is not decomposed by 
 hydrochloric acid. Strong sulphuric acid dissolves it, forming a brown solution from 
 which the alizarin is precipitated by water in orange-coloured flakes. Nitric acid at 
 the boiling heat dissolves it, with evolution of red vapours, forming phthalic acid and 
 probably also oxalic acid (Wolff and Strecker): 
 
 C 10 H 6 3 + IPO -i- 40 = C 8 H 6 O + C 2 H 2 4 
 
 Alizarin. Phthalic Oxalic 
 
 acid. acid. 
 
 It is also converted into phthalic acid by boiling with ferric chloride or nitrate 
 (Schunck). Chlorine converts it, when suspended in water, into a yellow substance 
 which dissolves in alkalis without much colour, and yields a colourless sublimate when 
 heated. 
 
 Alizarin dissolves in caustic alkalis and in alkaline carbonates, forming deep purple 
 solutions, from which it is precipitated by acids in orange-coloured flakes. The ammo- 
 niacal solution gives off all its ammonia by evaporation, and forms with the chlorides 
 of barium and calcium purple precipitates which become nearly black when dry. The 
 potash solution is completely decolorised by lime-water, a precipitate being formed 
 containing 2C'H fi 3 .3CaHO, or 2C* H 6 6 .3(CaO,HO\ With baryta, in a similar 
 manner, two compounds are formed, viz. 2C 10 H0 3 .3BaHO and C IS H 6 3 .2BaHO. Alu- 
 mina decolorises an alcoholic solution of alizarin, forming a beautiful red lake. An 
 timinoniacal solution of alizarin forms with salts of magnesium, iron, copper, and silver, 
 
ALKALI. 115 
 
 purple precipitates with a re-1 or bluish iridescence. The silver precipitate becomes 
 reduced after some time. The alcoholic solution of alizarin forms with an alcoholic 
 solution of acetate of lead, a purple precipitate containing 4C lo H 5 Pb0 3 .3Pb 8 0, or 
 2C*H*Pb0 6 .3PbO, according to Schunck, and 3C l H 6 3 .2Pb 2 0, according to Debus. 
 ALIZITE. (See PIMELITE.) 
 
 AXiKJlXiX. Alcali, Laugensalz. The word alkali is used in various senses. In 
 its most restricted, but most usual sense, it is applied to four substances only : hydrate 
 of potassium (potash), hydrate of sodium (soda), hydrate of litlmun (lithia), and hy- 
 drate of ammonium (which may be supposed to exist in the aqueous solution of ammonia). 
 In a more general sense, it is applied to the hydrates of the so-called alkaline earths 
 (baryta, strontia, and lime), and to a large number of organic substances both natural 
 and artificial, which are more fully described in the articles ALKALOIDS and AMMONIUM- 
 BASES. The first four bodies are sometimes spoken of as alkalis proper, when it is 
 wished specially to distinguish them from the other alkalis. 
 
 As the individual alkalis are described with sufficient detail in the articles specially 
 devoted to each, we shall confine this article to a discussion of those properties which 
 they all possess in common ; in order, as far as possible, to define the essential nature 
 of alkalinity, and to point out upon what grounds this or that particular body is classed 
 as an alkali. These objects will probably be best attained by tracing the most im- 
 portant of the successive steps by which the word alkali, which was at first the name 
 of a single substance, has come to be the generic name of an indefinite number of bodies. 
 
 The term alkali was first used in chemistry to designate the soluble part of the ashes 
 of plants, especially of sea-weed (carbonates of sodium and potassium). It was, how- 
 ever, soon extended to several similar substances which were obtained by other pro- 
 cesses : for instance, to salt of tartar, and to carbonate of potassium obtained by heat- 
 ing nitre with charcoal. The substances obtained by these processes, and by others 
 of like nature, were regarded as identical, or at most, as mere varieties of the same 
 substance. Alkali was, therefore, not yet used as a generic name, but as the specific 
 name of a particular substance. The character which was chiefly depended upon for 
 distinguishing alkali from other substances was the property of effervescing with acids. 
 This property was supposed to be characteristic of, and essential to, alkaline bodies, 
 till after the middle of the 18th century. Another property of alkali which was early 
 observed was its opposition to acids, and power of destroying their most distinctive 
 characters. On account of its possessing these properties, carbonate of ammonium, 
 which had been known since the thirteenth century, was, from the beginning of the 
 seventeenth century, regarded as a kind of alkali. The power of alkali to change many 
 vegetable colours was recognised at a later period than the properties above mentioned, 
 but was well known to Boyle, who also knew that colours which had been thus altered 
 could be restored by acids. 
 
 It was first clearly established in 1736, by Duhamel, that there existed two essentially 
 distinct kinds of fixed alkali. From this time, three kinds of alkali were recognised, 
 vegetable alkali, mineral alkali, and volatile alkali, corresponding respectively to 
 potash, soda, and ammonia, or to their carbonates. 
 
 We have already said that, far on in the eighteenth century, the power of efferves- 
 cing with acids was regarded as an essential property of alkalis. Boyle had indeed 
 observed, in 1684, that volatile alkali could be obtained by distillation over quick lime 
 in a condition in which it no longer effervesced with acids, although it retained all its 
 other usual properties. But, notwithstanding isolated observations of this kind, non- 
 effervescing alkalis were regarded rather as subordinate varieties of the ordinary 
 alkalis than as essentially different substances. 
 
 Moreover, it was known at a very early date, that quick lime altered, some of the 
 properties of alkali. This alteration was expressed by calling alkali, which had not 
 been acted on by lime, mild, and alkali which had been so acted on, caustic. The 
 effect of the lime was ascribed by Basil Valentine (latter half of the fifteenth century) 
 to heat (" die Hitze aus dem lebendigen Kalk") which it imparted to the alkali. And 
 the idea that lime in burning combined with an active principle " matter of fire " 
 which it gave out again partially to water (when slaked), and completely to alkali, 
 remained long dominant. Van Helmont (circ. 1640) regarded the substance taken up 
 by lime as a kind of sulphuric acid, whence the heat evolved in the action of water on 
 quick lime. Meyer, as recently as 1764, supposed the lime-salt of a peculiar acid, 
 acidum pingue, to be formed during the burning of lime, and that when this salt was 
 treated with a mild alkali, a corresponding alkaline salt (caustic alkali) was obtained. 
 The greasy feel of the caustic alkalis suggested the name of the acid which Meyer 
 supposed them to contain.* 
 
 * It is a remarkable illustration of the change which takes place in the ideas attached to the same 
 wonl. that both Van Helmont and Meyer should have attributed what we consider an exaltation of the 
 alkaline property to the agency of an acid. (See Arms, p. 40.) 
 
 I 2 
 
116 ALKALI. 
 
 The true nature of the difference between caustic and mild alkalis was discovered 
 by Black in 1755. Black's investigation of this subject occupies so important a place 
 in the history of general chemical theory, that it is worth while to consider a little in 
 detail his experiments and the conclusions he derived from them. 
 
 His first observation was that quick lime, when deadened by exposure to air, became 
 heavier, not lighter, as was to be expected, if the change which took place consisted 
 in the escape of fire-matter. He made a similar observation in the case of magnesia 
 (a substance which he had previously found to be distinct from lime). He found further 
 that magnesia, in the state in which it effervesces with acids, lost considerably in 
 weight when calcined, and that it then no longer effervesced with acids, although it 
 formed with them salts exactly similar to those of effervescing magnesia. In order to 
 find out what was the substance which effervescing magnesia lost when calcined, he 
 repeated the calcination in a retort connected with a well cooled receiver. In this 
 experiment, he obtained nothing but a small quantity of water ; it occurred to him, 
 however, that a gas might have escaped, and that this gas might be the same as that 
 which is evolved during the solution of magnesia alba (effervescing magnesia) in acids. 
 Following out this supposition, he came to the conclusion that the effervescing mag- 
 nesia which is precipitated by a mild alkali from a solution of calcined (not effervescing) 
 magnesia in acid, could obtain the gas, which caused it to effervesce when dissolved, 
 from no source except the alkali. Hence he concluded further that the mild alkalis 
 contain the same gas as is expelled from magnesia alba by calcination ; that, when 
 they combine with acids, this gas is separated and causes effervescence ; and that, 
 when a magnesia salt is precipitated by a mild alkali, the gas leaves the latter and 
 unites with the magnesia, in cmbination with which it is precipitated. These con- 
 clusions were verified by the following quantitative experiment. A weighed quantity 
 of magnesia alba was calcined ; it then dissolved in sulphuric acid without effervescence. 
 The solution was precipitated by mild vegetable alkali (carbonate of potassium), the 
 precipitate washed, dried, and weighed : its weight was almost exactly the same as 
 thatof the original magnesia alba, and it behaved' in every respect like that substance. 
 On a further examination of the gas, which is expelled by acids from the mild alkalis 
 and lime, and from magnesia alba, Black found it to be the same as that which is formed 
 during fermentation, and gave it the name fixed air. 
 
 From the sum of his observations, Black deduced the following general conclusions. 
 The effervescing earths and alkalis contain fixed air, which can be expelled from the 
 former by heat, though not from the latter, but which is expelled from both by acids ; 
 the alkalis and earths are caustic when they contain no fixed air, and therefore their 
 causticity does not depend on the presence of any peculiar constituent, but is a pro- 
 perty possessed by them in a state of purity; quicklime renders the alkalis caustic, 
 not by imparting to them any principle of causticity, but by the removal from the in 
 of fixed air ; lastly fixed air partially neutralises the alkalis by combining with them, 
 insomuch as it destroys their causticity. 
 
 Two of the most important effects which the adoption of Black's theory had upon 
 the received ideas of alkalinity were that it caused chemists to perceive (which they 
 had not done before), a necessary opposition between the causticity of an alkali and 
 its power of effervescing with acids, and caused the term alkali to be transferred from 
 the carbonated to the caustic alkalis. 
 
 Besides the substances to which the name alkali was first given, it was soon per- 
 ceived that certain kinds of earth possessed, in some degree, alkaline properties ; that 
 is to say, the power of effervescing when acted on by acids, and of neutralising their 
 acid properties. Earths which possessed these qualities were called terr<e absorbentes, 
 or terras alcalina, and were long supposed to owe their peculiarities to the presence 
 of alkali as one of their constituents. 
 
 It is not easy to make any precise statement as to the degree of similarity or of 
 difference which was supposed to exist between these bodies and alkali proper. The 
 difficulty arises partly from the fact, that, until they had acquired some idea of the 
 principles of chemical analysis, chemists had no sure means of ascertaining the iden- 
 tity or individuality of chemical substances, and hence often called different bodies by 
 the same name, or, on the other hand, gave different names to the same substance 
 when obtained by different processes ; partly also, from the word alkali having been 
 used formerly as now in various senses : by Lemery, for instance, to include all sub- 
 stances which effervesce with acids; by Stahl, to include all those which neutralise 
 acids ; by many others, however, to denote none but the substances now known as the 
 alkaline carbonates. This uncertainty in the use of the word is not surprising, when 
 we remember that our present more extensive knowledge does not enable us to point 
 out any one difference of fundamental importance between the alkalis and the alkaline 
 earths.. The different solubility in water of their carbonates probably furnishes a more 
 exact distinction than any other single property. This character was pointed out by 
 
ALKALI. 117 
 
 Diihamel in 1736, as a generic difference. He distinguished earths from alkalis by 
 the property which the latter have of precipitating the former from their solutions, 
 and the alkaline earths from others by their capability of completely neutralising acids. 
 These distinctions have, for the most part, been ever since retained. 
 
 It is not necessary to discuss with much detail early ideas relating to the ultimate 
 constitution of the alkalis and alkaline earths. A similarity of constitution between 
 the earths and metallic calces was soon suspected ; in consequence of which Neumann, 
 before the middle of the eighteenth century, endeavoured to get a metal from quick 
 lime. By the later phlogistic chemists, both alkalis and earths were, like metallic 
 calces, regarded as simple bodies. Lavoisier, though he regarded metallic calces as 
 compounds, continued to class the alkalis and earths among elementary bodies, inas- 
 much as there was no known means of decomposing them. He considered it probable, 
 however, that they contained oxygen, and suggested that the earths might be oxides 
 of metals which had a greater affinity for oxygen than carbon, and therefore could 
 not be reduced. Many attempts were made by Lavoisier's followers to verify these 
 suppositions ; but their uniform failure seemed almost to have proved the elementary 
 nature of the bodies in question, when, in 1807, Sir Humphry Davy succeeded in re- 
 ducing potash and soda by the galvanic current. The composition of volatile alkali 
 (ammonia), was approximately ascertained by Berthollet in 1785. After the discovery 
 of oxygen in the fixed alkalis, it was long supposed by Davy and Berzelius that am- 
 monia also contained oxygen. The idea that aqueous ammonia contained the oxide of 
 a compound metal, which likewise existed in the ammonia-salts, was suggested by 
 Berzelius in 1820. (See AMMONIUM.) 
 
 In the present state of chemical theory, the relations of the alkalis to other sub- 
 stances lead to the representation of them as hydrates, or as water in which half the 
 hydrogen is replaced by a metal, or compound radicle. (See TYPES.) 
 
 The earliest addition made by modern chemistry to the old list of alkalis was morphia, 
 discovered in opium by Serturner in 1805, but first fully described by him in 1817. 
 This was the first organic alkali, or alkaloid which became known ; but, when the 
 general attention of chemists was directed to its existence, it was soon found to be 
 one of a very numerous class of compounds (see ALKALOIDS). Of late years, a large 
 number of bodies, possessing many points of resemblance to the natural alkaloids have 
 been obtained by artificial processes. The constitution of these artificial alkalis is 
 similar to that of hydrate of ammonium: they represent hydrate of ammonium in 
 which hydrogen is replaced by an electro-positive radicle (in most cases a hydrocarbon), 
 (see AMMONIUM-BASES), or in which nitrogen is replaced by phosphorus, arsenic, or 
 antimony. 
 
 The following properties are common to the mineral alkalis and to many of the 
 organic alkalis. 
 
 (1) They are more or less soluble in water, the alkalis proper much more so than 
 the alkaline earths. (2) They neutralise completely the strongest acids, and with 
 weak acids form salts possessing in some degree, alkaline properties. (3) Their aqueous 
 solutions exert a caustic or corrosive action on vegetable and animal substances ; (4) 
 precipitate the heavy metals from most of their acid solutions as hydrates or as oxides ; 
 (5) and alter the tint of many colouring matters ; for instance, they turn litmus, which 
 has been reddened by acid, blue, they turn turmeric brown, and syrup of violets and 
 infusion of red cabbage, green. The extent to which the various alkalis dissolve in 
 water appears to determine the degree in which they possess the last three properties 
 (3, 4, 5), the most soluble possessing them in a greater degree than the rest. The action 
 on colouring matters appears to belong to all metallic hydrates which are soluble in 
 water, and is possessed by the hydrates of lead, silver, and mercury, in a degree cor- 
 responding to their slight solubility. 
 
 (For further historical details concerning alkalis and alkaline earths, see Kopp, 
 Geschichte der Chemie, vols. iii. and iv.). Gr. C. F. 
 
 .ft.Xi2C&XiXnZETRir is the determination of the amount of real alkali in alkaline 
 mixtures and liquids, such as the commercial carbonates of potassium and sodium, 
 (commonly called potash and soda), in wood-ashes, solutions of caustic and carbonated 
 alkalis, &c. This estimation, like that of the strength of acids, may be made either 
 by volumetric or by weight-analysis* 
 
 The volumetric method of alkalimetry is merely a particular case of the general 
 method of " Analysis by Saturation," described in the article ANALYSIS, VOLUMETRIC 
 (which see). The valuation f an alkali by the amount of a standard acid solution 
 which it will saturate, was first introduced by Descroizille, afterwards perfected 
 by Gay-Lussac, and still farther by Mohr. (Lehrbuch der chemisch-analytischen 
 Titrirmethode, Braunschweig, 1855.) 
 
 Instead of the sulphuric or hydrochloric acid generally used for the purpose, Mohr 
 recommends oxalic acid, because it can be weighed with greater accuracy than any 
 
 i 3 
 
118 ALKALIMETRY. 
 
 liquid acid, and because its standard solution may be kept for any length of time with- 
 out change. To obtain it pure, the commercial acid, which is generally contaminated 
 with the oxalates of potassium and calcium, is finely pounded, and treated with a 
 quantity of lukewarm water sufficient to dissolve only a portion of it ; the solution is 
 filtered and left to crystallise ; and the crystals are collected on a filter and dried in 
 the air, till they no longer adhere to each other or to the paper. The acid is thus 
 obtained pure, and containing exactly C 2 H 2 4 + 2H 2 0, the atomic weight of which 
 is 126. 
 
 The standard solution is best made of such a strength that 1000 cubic centimetres 
 (1 litre), shall contain exactly one ^-gramme-atom (i.e. I atom expressed in |-grammes) 
 of the acid. This is effected by dissolving in water i| = 63 grammes of the crystals, 
 and diluting the solution to the bulk of 1 litre. 1000 c. c. of this solution contain one 
 |-gramme-atom of acid : hence 2 c. c. contain 1 milligramme-atom of acid, and 
 saturate 2 milligramme-atoms of a caustic alkali (KHO or NaHO), 1 milligramme of 
 an anhydrous alkali (K 2 or Na 2 0), or of an alkaline carbonate (C0 3 K 2 or C0 3 Na 2 .) 
 
 To estimate the value of a sample of commercial potash or soda, 3 or 4 grammes of 
 it are first ignited in a platinum crucible in order to determine the amount of water 
 contained in it. The residue is then dissolved in water ; a few drops of litmus are 
 added ; and the standard acid is gradually added from a burette till the first appearance 
 of a purple-red or wine-red colour. This takes place when a little more than half the 
 alkaline carbonate is decomposed by the oxalic acid : for the first portions of carbonic 
 acid disengaged by the oxalic acid, unite with the remaining portion of alkaline car- 
 bonate to form acid carbonate, and it is only when half the alkali has been neutralised 
 in this way that the carbonic acid is actually set free and reddens the litmus. After 
 this stage has been attained, the oxalic acid must be very cautiously added till the 
 purple-red produced by the carbonic acid, just passes into a bright yellowish-red, in- 
 dicating the presence of free oxalic acid, and showing that the whole of the alkali is 
 neutralised by that acid. Each c. c. of acid thus employed corresponds to 1 milli- 
 gramme of caustic alkali, or to one |-milligramme of alkaline carbonate, i.e. to 0-040 
 grm. caustic soda (NaHO), 0-056 grm. caustic potash (KHO), 0'069 grm. carbonate 
 of potassium (CO S K 2 ), and 0'053 grm. of carbonate of sodium. The amount of caustic 
 alkali or alkaline carbonate is then found by a simple proportion ; thus : 
 
 100 : 5'3 : : number of c. c. employed : amount of carbonate of sodium. 
 
 By operating on 100 times the |-milligramme-atom (e.g. 6 -9 grms. of carbonate of 
 potassium, or 5*3 grms. of carbonate of sodium), all calculation is saved : for as this 
 amount, if perfectly pure, would require 100 c. c. of acid for its saturation, the number 
 of c. c. actually required indicates at once the percentage of alkaline carbonate. The 
 burettes commonly used contain 50 c. c., and are graduated into half c. c. ; so that by 
 operating on 50 times the |-milligramme-atom, the number of divisions employed in- 
 dicates the percentage. 
 
 In operating upon alkaline carbonates in the manner just described, it is difficult to 
 notice the exact moment when the wine-red colour of the litmus due to the presence 
 of free carbonic acid, changes to the light red produced by oxalic or other strong acid. 
 For this reason Mohr recommends the following, called the residual method. The 
 standard acid is added till the colour of the litmus is distinctly bright red ; the solu- 
 tion is then heated to boiling, and a slight excess (5 to 10 c. c.) of acid is added. 
 The hot solution is freed from carbonic acid by agitation and by drawing air through 
 it by means of a glass tube, and then neutralised with a standard solution of caustic 
 soda (ANALYSIS, VOLUMETRIC), till the colour just changes from red to blue.^ Since 
 the acid and alkaline solutions neutralise each other, volume for volume, it is only 
 necessary to deduct the number of cubic centimetres employed of the latter from 
 that of the former, and calculate the amount of alkali from the residue. In esti- 
 mating the strength of caustic alkaline solutions, this residual method is of course 
 unnecessary. 
 
 To determine the proportion of caustic alkali and alkaline carbonate in a mixture of 
 the two, two equal portions of the solution must be taken : one of them treated with 
 chloride of barium, whereby the alkaline carbonate is converted into chloride, and car- 
 bonate of barium is precipitated. The liquid is filtered and the quantity of caustic 
 alkali determined in the filtrate as above. The second portion of the solution is 
 neutralised with the standard acid, without previous treatment with chloride of barium, 
 and the total amount of alkali, existing both in the caustic state and as carbonate, is 
 thereby determined. The first result deducted from the second, gives the quantity of 
 alkali existing as carbonate. 
 
 If it be preferred to make these estimations with the ordinary English ^weights and 
 measures, the standard solution of oxalic acid may be made by dissolving 63 grains 
 (^grain-atom) of the crystallised acid in water and diluting the solution to 1000 
 
ALKALIMETRY. 
 
 119 
 
 Fig 
 
 grain -measures at 60 F. This quantity of the solution will then neutralise 1 grain- 
 atom of a caustic alkali (40 grains of soda NaHO, or 56 grains of potash KHO), and 
 i-grain-atom of alkaline carbonate (69 grains of C0 3 K 2 , or 53 grains of C0 3 Na 2 ), and by 
 operating on -^ of these quantities of the substance to be tested, the percentages will 
 be given at once by the number of grain-measures of the standard acid employed. 
 
 A convenient method of estimating by volumetric analysis the proportion of potash 
 and soda in a caustic mixture of the two, has been kindly communicated to the Editor 
 by Mr. John Dale of Cornbrook, near Manchester. It depends upon the fact that 
 acid tartrate of potassium, though moderately soluble in water, is but very sparingly, 
 if at all, soluble in a liquid containing acid tartrate of sodium. The method is as 
 follows : Add to the mixture a standard solution of tartaric acid till an acid reaction 
 just becomes perceptible ; the alkalis are thereby converted into neutral tartrates ; 
 then add a second quantity of tartaric acid equal to the first, so as to convert them 
 into acid tartrates : the whole (or nearly the whole) of the acid tartrate of potassium 
 then separates. Next filter off the solution of acid tartrate of sodium, and add a 
 standard solution of caustic soda till the liquid just exhibits an alkaline reaction. 
 The quantity of the soda solution thus added is equal to the amount of soda present 
 in the mixture. The quantity of tartaric acid required to form acid tartrate with the 
 soda, subtracted from the total quantity added to the mixture of the two alkalis, gives 
 the quantity required to form acid tartrate with the potash ; and thus the amount of 
 potash is determined. This method would scarcely be applicable where scientific 
 accuracy is required ; but, for rapid estimation in commercial practice, it is found to 
 give good results. 
 
 Alkalimetry by Weight-analysis. The proportion of alkali in the commercial car- 
 bonates of potassium and sodium may be estimated by determining the quantity of car- 
 bonic anhydride evolved when the carbonates are decomposed 
 by an acid : for 22 parts of carbonic anhydride (CO 2 ) corre- 
 spond to 69 parts of carbonate of potassium (C0 3 K 2 ), and to 
 53 parts of carbonate of sodium (C0 3 Na 2 ). The apparatus 
 employed is the same as that described in the article ACIDI- 
 -METRY; but the method of using it is slightly different, A 
 weighed quantity of the carbonate to be examined is dis- 
 solved in warm water in the flask A, and a quantity of hydro- 
 chloric or dilute sulphuric acid more than sufficient to 
 decompose the carbonate, is placed in a short test-tube b, 
 which is carefully introduced into the flask, so that it may rest 
 against the side. The apparatus having been then weighed, 
 the extremity of the tube c is closed by a plug of wax, and 
 the flask is tilted so that the acid may run over into the 
 alkaline liquid. When the evolution of gas ceases, the flask 
 is heated to complete the decomposition ; the wax plug is 
 removed and air drawn through the apparatus to remove the 
 carbonic acid remaining in it ; and the flask after cooling is 
 again weighed to ascertain the loss of carbonic acid. At 
 the conclusion of the experiment, a piece of blue litmus-paper must be thrown into the 
 flask, to try whether the liquid is acid ; if not, more acid must be added, and the pro- 
 cess repeated. 
 
 The apparatus of Will and Fresenius (jig. 6) may also be used. The alkali dis- 
 solved in water is then placed in the flask A, and 
 strong sulphuric acid in B ; and the whole appa- 
 ratus is weighed; the tube a b is closed with a 
 wax plug ; and suction is applied by the mouth at 
 the end of the tube d, so as to draw a few bubbles 
 of air from A into B. On discontinuing the suction 
 the pressure of the air forces a small quantity of the 
 acid in B into the flask A, whereby a portion of the 
 alkaline carbonate is decomposed. This process is 
 repeated as long as any gas continues to be evolved, 
 after which the flask A is heated, and the experi- 
 ment completed in the manner just decribed. 
 
 If the alkaline carbonate contains any caustic al- 
 kali, which may be known (in the absence of sul- 
 phide), by its solution having an alkaline reaction 
 after the addition of excess of chloride of barium, 
 another equal portion must be mixed with about one- 
 third of its weight of carbonate of ammonium, and 
 3 parts of quartz-sand (to prevent caking), and heated till the water and ammonia are 
 
 i 4 
 
 Fig. 6. 
 
120 ALKALOIDS. 
 
 expelled ; the dry residue is then decomposed as above. The excess of alkaline car- 
 bonate obtained in the second determination is due to the caustic alkali in the sample, 
 which is converted into carbonate by ignition with the carbonate of ammonium ; and 
 from it the amount of caustic alkali is easily calculated ; thus for soda : 
 CO'Na 2 : 2NaHO [or CO*.NaO : NaO.HO] = 106 : 80. 
 
 The sulphites, hyposulphites, and sulphides of the alkali-metals, which often occur 
 in commercial samples of alkali, especially in " ball-soda," introduce errors both into 
 the volumetric and the weight-analyses : into the former, by neutralising a portion of 
 the test-acid, and into the latter by evolving sulphurous acid or sulphuretted hydro- 
 gen, which would be estimated as carbonic acid. When the amount of alkali is to be 
 determined by the volumetric method, these compounds may be decomposed by igniting 
 the substance with chlorate of potassium, whereby they are all converted into sulphates. 
 For the carbonic acid estimation, they may be oxidised by adding a small quantity of 
 neutral chromate of potassium to the solution in the flask,, before commencing the de- 
 composition. 
 
 The carbonates of the earths, which would introduce similar errors, may be removed 
 by dissolving the alkaline carbonate in water and filtering. 
 
 AIiX. AXiOXDS. Organic Alkalis, Organic Bases. At the beginning of this century, 
 the only substances in which alkaline properties had been recognised were potash, 
 soda, ammonia, and the alkaline earths (see ALKALI). In 1817, Sertiirner drew 
 attention to the existence in opium of a substance whose alcoholic solution acted upon 
 vegetable colours like the solutions of the alkalis, which combined directly with acids, 
 forming neutral salts, soluble in water, and giving the usual reactions of the acids 
 from which they were formed ; and which was precipitated from solutions of its salts 
 by the mineral alkalis. To this substance, Sertiirner gave the name morphine, and 
 in consequence of its possessing the properties just mentioned, regarded it as a kind 
 of alkali. After the discovery of morphine, it was soon found that many vegetable 
 products which had been long known as exerting marked physiological effects (e. g. 
 cinchona bark, nux vomica, tobacco, &c.), contained similar alkaline principles. The 
 number of such natural alkaloids now known is very great, and includes many sub-^ 
 stances which cannot in any strict sense be termed alkalis, but which are connected by 
 such insensible gradations (between intermediate terms) with substances decidedly 
 alkaline, that they must be regarded as possessing essentially the same chemical 
 nature as the latter. Since 1848, a great number of organic alkalis have been obtained 
 artificially. Some of these rival potash and soda in the degree of their alkalinity, 
 while in others the existence of alkaline properties is barely perceptible. 
 
 The only property which is possessed by all alkaloids, whether natural or artificial, 
 is that of combining directly with acids to form salts possessing a certain degree of 
 stability, and capable, when dissolved in water, of producing the ordinary phenomena 
 of saline double decomposition. Those alkaloids, whose salts possess any considerable 
 degree of stability, generally exhibit, when dissolved in water or alcohol, an alkaline 
 reaction with vegetable colours. 
 
 Most of the natural alkaloids contain carbon, hydrogen, nitrogen, and oxygen, and 
 are, at ordinary temperatures, solid, and not volatile without decomposition. Some 
 natural alkaloids contain carbon, hydrogen, and nitrogen only; these are, for the 
 most part, liquid at ordinary temperatures, and can be distilled without decomposition. 
 The greater number of the artificial alkalis are composed of carbon, hydrogen, and 
 nitrogen ; some, however, contain oxygen in addition. In both natural and artificial 
 alkaloids, hydrogen may be replaced by chlorine, bromine, iodine, peroxide of nitrogen, 
 &c. Alkaloids have also been obtained artificially, in which nitrogen is replaced by 
 phosphorus, arsenic, antimony, or bismuth. (See PHOSPHINES, ARSESTES, &c.) 
 
 Most of the alkaloids, as they are obtained in the free state, correspond in compo- 
 sition to ammonia, NH 3 , rather than to the fixed alkalis ; that is to say, they form 
 salts by direct union with acids, without elimination of water or any other substance. 
 In order to make them strictly comparable to the fixed alkalis, they require, like am- 
 monia, the addition of IPO to their formulae : they may then be considered as hydrates 
 of compound radicles analogoxis to ammonium. A few alkaloids, however, are known 
 which, when dehydrated as far as possible, correspond precisely to the fixed alkalis ; 
 e.g. hydrate of tetrethylium, C 8 H 2I NO = C 8 H-N.H.p. These bodies, for the most 
 part, resemble potash and soda very closely in properties. 
 
 The constitution of most of the artificial alkaloids is tolerably well known. The 
 processes by which they are obtained show that they must be considered as ammonia, 
 or as hydrate of ammonium, in which the hydrogen is replaced wholly, or in part, by 
 a compound radicle generally composed of carbon and hydrogen (see AMIDES, AM- 
 MONIUM-BASES). The phosphorus, arsenic, &c. alkaloids are similarly related to 
 phosphide, arsenide, &c. of hydrogen, PH 3 , AsH 3 , &c. The constitution of the natural 
 
ALKALOIDS. 
 
 121 
 
 alkaloids is, as yet, very imperfectly understood. They are probably, like the artificial 
 alkalis, derivatives of ammonia ; but it is unknown by what radicles the hydrogen is 
 replaced. 
 
 The following is a list of the most important nitrogen-alkaloids, natural and arti- 
 ficial, which are now known. 
 
 1. Alkaloids comparable to ammonia, forming salts by direct union with acids. 
 
 Name. 
 
 Acediamine . 
 ? Acetonine . 
 Acetylamine. 
 Aconitine 
 Alanine 
 
 Alkaloid 
 Alkaloid 
 
 . C 2 HN 2 
 . C 9 H 18 N 2 
 (See VINYL AMINE.) 
 
 . C 30 H 47 N0 7 
 . C 3 H 7 N0 2 
 
 Formula. Source or Mode of Formation. 
 
 Acetamide heated in hydrochloric acid gas. 
 Action of ammonia on acetone. 
 
 Alkaloid . 
 Alkaloid . 
 Allylamine , 
 
 Dibromdiallylamine . 
 
 Ethyldibromdiallylamine . 
 Amarine . . . 
 
 Diethylamarine . 
 Ammeline . 
 Amylamine . 
 
 Diamylamine 
 
 Diethylamylamine 
 
 Methylethylamylamine 
 
 Triamylamine . 
 Aniline. (See PHENYLAHINE, 
 Anisine . 
 Aricine . 
 
 Asparagine . 
 Atropine . 
 Azonaphtylamine . 
 Azophenylamine . 
 Bebirine , 
 
 C 3 H 5 N, 
 C 4 H 8 N 4 
 
 C 8 H 13 NO 
 C 10 H 15 NO 
 
 C 3 H 7 N. 
 
 C 6 H 9 Br 2 N 
 
 C 8 H 13 Br 2 N. 
 
 C 21 H 18 N 2 
 
 C 25 H 26 N 2 . 
 
 C 5 H !3 N. 
 C 10 H 23 N. 
 
 C 9 H 21 N; 
 
 C 8 H I9 N. 
 C 15 H 33 N. 
 
 C 22 II 24 N 2 3 
 C 23 H- 6 N 2 4 
 C 4 H 8 N 2 3 
 C I7 H 23 N0 3 
 
 Aconitum Napelhis. 
 
 Hydrochloric and hydrocyanic acids on 
 
 aldehydammonia. 
 
 Nitrous ether on creatine (D e s s a i g n e s). 
 Distillation of ethylcyanamide (Cahours 
 
 and Cloez). 
 
 From aldehydammonia (Bab o). 
 
 Tribromide of allyl on ammonia 
 
 Potash on hydrobenzamide. 
 
 Strong acids or alkalis on cyanamide. 
 
 Action of heat on anishydramide. 
 Cinchona bark. 
 
 Asparagus officinalis, and other plants. 
 Atropa belladonna, Datura Stramonium. 
 Reduction of dinitronaphtalene. 
 C 6 H 8 N 2 . Reduction of dinitrobenzine. 
 
 "Bebceru," a species of Ncctandra, British 
 Guiana. 
 
 Benzidine . 
 
 Berberine 
 Brucine 
 
 Ethylbrucine 
 
 . C 12 H 12 N 2 
 
 . C 21 H' 9 N0 5 
 . C 23 H 26 N 2 0< 
 
 . C 25 H 80 N 2 4 . 
 
 Caffeine .... C 8 H 10 N 4 2 
 Caproylamine. (See HEXYLAMINE.) 
 Caprylamine. (See OCTYLAMINE.) 
 Carbamide. (See UREA.) 
 Carbotriphenyltriamine, or 
 Cyantrphenyldiamine 
 
 Reducing agents on azobenzide and on 
 
 azoxibenzide. 
 Herberts vulgaris. 
 Strychnos nux vomica, S. Ignatii, S. 
 
 Colubrina. 
 
 Tea, coffee, &e. 
 
 Carbothiiildine 
 
 C I9 H 17 ON 3 
 
 Bichloride of carbon on phenylamine. 
 C 5 H 10 N 2 S 2 . Sulphocarbonie anhydride on aldehyd- 
 
 Cetylamine. 
 
 
 
 
 Tricetylamine . 
 
 
 C 48 H"K 
 
 
 ? Cheliclonine 
 
 
 C 20 H 19 N 3 S 
 
 . Chelidonium majus. 
 
 Cinchonicine 
 
 
 C 20 H 24 N 2 
 
 . Isomeric transformation of cinchonine or 
 
 
 
 
 of cinchonidine. 
 
 Cinchonidine 
 
 
 C 20 H 24 N 2 
 
 . Cinchona bark. 
 
 Methylcinchonidine 
 
 
 C 21 H 26 N 2 0. 
 
 
 Cinchonine 
 
 
 C M H 24 N 2 
 
 . Cinchona bark. 
 
 Methylcinchonine 
 
 
 C 21 H 26 N 2 0. 
 
 
 Codeine 
 
 
 C 18 H 21 N0 3 
 
 . Opium, 
 
 Ethylcodoine 
 
 
 C 20 H 25 N0 9 . 
 
 .r 
 
122 
 
 ALKALOIDS. 
 
 Name. 
 
 Formula. 
 
 Source or Mode of Formation. 
 
 Colchiceine . 
 
 C 35 H 44 N 2 n 
 
 Colchicum autumnale. 
 
 Collidine 
 
 C 8 HN 
 
 . Bone-oil. 
 
 Conhydrine . 
 
 C^H^O 
 
 . Hemlock (Conium maculatum). 
 
 Conine . . 
 
 C 8 H 15 N 
 
 . Hemlock (Conium maculaturni). 
 
 Ethylconine 
 
 C'H 19 N. 
 
 
 Methylconine 
 
 C 9 H 17 N. 
 
 
 Cotarnine 
 
 C 12 H 13 N0 3 * 
 
 . Oxidation of narcotine. 
 
 Coumaramine 
 
 C 9 H 7 N0 2 
 
 . Reduction of nitro-coumarine. 
 
 Creatine 
 
 C 4 H 9 N 3 2 
 
 . Juice of flesh. 
 
 Creatinine . 
 
 C 4 H 7 N 3 
 
 . Action of acids on creatine. 
 
 Cryptidine 
 
 CH n N 
 
 . Coal-tar. 
 
 Cumidine 
 
 C 9 H 13 N 
 
 . Reduction of nitro-cumine. 
 
 Cyanamide . 
 
 CH 2 N 2 
 
 . Gaseous chlor. of cyanogen on ammonia. 
 
 Amylcyanamide 
 
 C 6 H I2 N 2 . 
 
 
 Diamylcyanamide 
 
 C n H 22 N 2 . 
 
 
 Diethylcyanamide 
 
 C S H 10 N 2 . 
 
 
 Ethylcyanamide 
 
 C 3 H 6 N 2 . 
 
 
 Methylcyanamide 
 
 C 2 H 4 N 2 . 
 
 
 Methylethylcyanamide 
 
 C 4 H 8 N 2 . 
 
 
 Cyanethine .... 
 
 C 9 H 15 N S 
 
 . Potassium on cyanide of ethyl. 
 
 Cyanetholine 
 
 C S H 5 NO 
 
 . Chloride of cyanogen on ethylate of 
 
 
 
 sodium. 
 
 Cyaniline .... 
 
 C 14 H 14 N 4 
 
 Do. on phenylamine 
 
 
 
 (aniline.) 
 
 Cyanocumidine 
 
 C^H^N 4 
 
 Do. on cumidine. 
 
 Cyanomelamine . . n 
 
 C 15 H 13 N 5 
 
 Do. on melaniline. 
 
 Cyanotoludine 
 
 C 16 H 18 N 4 
 
 . . Do. on toluidine. 
 
 Diphenine . 
 
 C 12 H 12 N 4 
 
 . Reduction of dinitrazobenzide. 
 
 Diphenylformyldiamine 
 
 C 13 H 12 N* 
 
 . Chloroform on phenylamine. 
 
 Ethylamine . 
 
 C 2 IL r $ 
 
 
 Diethylamine . . 
 
 C 4 HN. 
 
 
 Triethylamine . 
 
 C 6 H I5 N. 
 
 
 Ethylenamine . . . 
 Diethylenamine . 
 
 C 2 H 8 N 2 ) 
 
 . Bromide of ethylene on ammonia. 
 
 Phenylethylenamine . 
 (orDiphenylbiethylenamine 
 Triethylenamine 
 
 C 16 H 18 N 2 '?E 
 
 C 6 H ,2 N 2 
 
 . Bromide of ethylene on phenylamine. 
 . Bromide of ethylene on ammonia. 
 
 Flavine . . 
 
 C 13 H 12 N 2 
 
 . Reduction of binitrobenzophenone. 
 
 Furfurine 
 
 C 15 H 12 N Z 3 
 
 . Furfuramide boiled with potash. 
 
 Glycocoll 
 
 C 2 H 5 N0 2 
 
 . Ammonia on chlor- or bromacetic-acid. 
 
 Glycosine 
 Glyoxaline 
 
 cSj 
 
 . Ammonia on glyoxaL 
 
 Guanine 
 
 C 5 H 5 N 5 
 
 . Guano, &c. 
 
 Harmaline . 
 Hydrocyanharmaline . 
 
 C 13 H 14 N 2 
 C 14 H I5 N 3 O 
 
 . Seeds of Peganum Harmala. 
 . Hydrocyanic acid and harmaline. 
 
 Harmine . 
 
 C 13 H' 2 N 2 
 
 . Seeds of Peganum Harmala ; also oxida- 
 
 
 
 tion of harmaline. 
 
 Hexylamine. 
 
 
 
 Trihexylamine . 
 
 C 19 H 39 N 
 
 . Sulphite of cenanthylsodium distilled with 
 lime. 
 
 ? Jervine . . 
 
 C 30 H 46 N 2 3 
 
 . Veratrum album, white hellebore. 
 
 Lepidine . 
 
 C 10 H 9 N 
 
 . Coal-tar; also quinine and cinchonine 
 
 
 
 distilled with potash. 
 
 Leucine . 
 
 CH' 8 N0 2 
 
 . Hydrochloric and hydrocyanic acids in 
 
 
 
 valeral ammonia. 
 
 Lophine . . . . 
 
 C 2i H i8 N a 
 
 . Distillation of hydrobenzamide. 
 
 Lutidine . , . , 
 
 C 7 H 9 N . 
 
 . Bone-oil. 
 
 Melamine .... C 8 H 6 N 6 . Action of heat on cyanamide. 
 * According to unpublished analyses by Matthiessen and Foster. 
 
ALKALOIDS. 
 
 123 
 
 Name. 
 Melaniline . 
 
 Menaphthylamine . 
 Methylamine 
 
 Dimethylamine . 
 
 Trimethylamine . 
 Methyluramine 
 
 Metoluidine . 
 Morphine 
 
 Ethylmorphine . 
 
 Methylmorphine 
 
 Naphtylamine 
 
 Ethylnapthylamine 
 Narceine . 
 Narcotine 
 
 Nicotine 
 
 Ninaphtylamine . 
 Octylamine . . 
 
 Papaverine . 
 Parvoline 
 
 Formula. 
 . C 13 H 13 N S 
 
 . C 21 H 13 N 3 
 . CH 5 N. 
 . C 2 H r N. 
 . C 3 H 9 N. 
 
 C 15 H 17 N 3 
 C I7 H 18 NO S 
 C I9 H i3 N0 3 . 
 C 18 H 21 N0 3 . 
 
 . C 12 H 13 N. 
 . C 24 H 29 N0 9 
 
 C1 H 14 N 2, 
 
 (C 5 HN ) 
 . C 10 H 8 N 2 
 
 . C 20 H 2I N0 4 
 . C 9 H W N 
 
 . C 18 H 21 N0 3 
 
 C 10 H 15 N. 
 C 38 H"N. 
 
 C 13 H 21 N. 
 C 8 HN. 
 
 C 12 H 19 N. 
 C 9 H I3 N. 
 C 7 H 9 N. 
 C 18 H 15 N 
 
 Pelosine, or Cissampeline 
 
 Phenylamine 
 
 Amylphenylamine 
 Diamylphenylamine . 
 Diethylphenylamine . 
 Dicetylphenylamine . 
 Cetylphenylamine 
 Ethylamylphenylamine 
 Ethylphenylamine 
 Methylamylphenylamine 
 Methylethylphenylamine 
 Methylphenylamine . 
 Triphenylamine . 
 
 Vinylphenylamine 
 (Phenylacetylamine 
 
 Phtalidine 
 Picoline 
 Piperidine . 
 
 Amylpiperidine . 
 
 Ethyl piperidine . 
 
 Methylpiperidine 
 ? Piperine 
 Propylamine. (See TEITYLAMINE.) 
 Pyridine .... C 5 H 5 N . 
 
 Quinicine 
 
 \ r * 
 
 ( C 16 H .8 N 2 
 
 . C 8 H 9 N . 
 
 C'H 15 N. 
 C 6 H I3 N. 
 
 Quinidine 
 Quinine 
 Ethylquinine . . 
 Methylquinine . 
 Quinoleine . 
 Amylquinoleine . 
 Ethylquinoleine 
 Methylquinoleine 
 
 . C 20 H 24 N 2 2 > 
 . C 20 H 24 N 2 2 J 
 . C 22 H 28 N 2 2 . 
 
 '. C 9 H 7 N . 
 
 '. C u H n N! 
 . C 10 H 9 N. 
 
 Source or Mode of Formation. 
 
 Cyananilide (cyanophenylamine) and 
 
 phenylainine. 
 Chloride of cyanogen on naphtylamine. 
 
 Creatine or creatinine heated with oxide 
 
 of mereury. 
 
 Chloride of cyanogen on toluidine. 
 Opium. 
 
 Eeduction of nitronaphtylene. 
 Opium. 
 
 Tobacco. 
 
 Reduction of dinitronaphtylene. 
 
 Opium. 
 
 Distillat. of bituminous shale of Dorset- 
 shire. 
 
 Cissampelos pareira, L. (Antilles). 
 Eeduction of nitrobenzene, &c. 
 
 Sulphite of cinnamyl-ammonium distilled 
 with lime. 
 
 Eeduction of nitrophtalene. 
 
 Coal-tar. 
 
 Piperine distilled with potash. 
 
 Pepper (Piper nigrum, P. longuni). 
 Bone-oiL 
 
 Isomeric transformation of quinine, or of 
 quinidine. 
 
 Cinchona bark. 
 
 Quinine or Cinchonine distiL with potash. 
 
 * According to unpublished analyses by Matthiessen and Foster. 
 
124 
 
 ALKALOIDS. 
 
 Name. 
 
 Sarcine . 
 
 Sarcosine 
 Sinamine 
 Ethylsinamine 
 
 Sinapine 
 Sinapoline . 
 
 Siucaline 
 Sparteine 
 
 Strychnine . 
 
 Tetrylamine (Petinine) 
 
 Thebaine 
 
 Theine. (See CAFEINE.) 
 
 Theobromine 
 
 ? Thiacetonine 
 
 Thialdine . . . 
 Thiosanime . 
 
 Ethylthiosanimine 
 Toluidine (Toluylamine) 
 Diethyltoluidlne 
 Ethyltoluidine . 
 Tritylamine . 
 
 Formula. 
 
 ' C 3 H 7 NO* 
 .' C 6 H'N 2 
 
 . C 16 H 28 N0 5 
 . C 7 H I2 N 2 
 
 . C 5 H I3 NO 
 . C S1 H 22 N 2 2 
 
 . C 4 H"N 
 . C 19 H 21 N0 3 
 
 . C 7 H 8 N 4 2 
 
 . C 9 H 19 NS 2 
 
 . C 6 H 13 NS 2 
 . C*H 9 N 2 S 
 
 . C 6 H 12 N 2 S 
 . C 7 H 9 N 
 . CH"N. 
 . C 9 H 13 N. 
 . C 3 H 9 N. 
 
 Urea (Carbamide . . . CHWO. 
 Allylurea .... C 4 H 8 N 2 0. 
 Amylurea .... C 6 H 14 N 2 0. 
 Diallylurea. (See SINAPOLINE.) 
 Diethylurea . . . C 5 H I2 N 2 0. 
 
 Diphenylurea. (See FLAVINE.) 
 Ethylallylurea 
 
 Ethylamylurea . 
 
 Ethylpiperylurea 
 
 Ethylurea . 
 
 Methylethylurea 
 
 Methylpiperylurea 
 
 Methylurea 
 
 Naphtylurea 
 
 Phenylallylurea 
 
 Phenylurea 
 
 Piperylurea 
 
 CH 12 N 2 0. 
 C 8 H 18 N 2 0. 
 C 8 H 16 N 2 0. 
 
 . C 4 H 10 N 2 0. 
 . C 7 H 14 N 2 0. 
 . C 2 H 6 N 2 0. 
 
 '. C 10 H 12 N 2 0! 
 . C 7 H 8 N 2 0. 
 C 6 H i2 N 2 0< 
 
 Sulphallylurea. (See THIOSINAMINE). 
 Tolylurea .... C 8 H 10 N 2 0. 
 
 Valeraldine . 
 Veratrine 
 ?Vinylamine . 
 
 C 15 H 31 NS 9 
 
 Source or Mode of Formation. 
 
 Juice of flesh. 
 
 Baryta- water on creatine. 
 
 Oxide of mercury on thiosinamine. 
 
 Ethylthiosinamine heated with hydrate 
 
 of lead. 
 
 White mustard. 
 Hydrate of lead in oil of mustard (sul- 
 
 phocyanate of allyl). 
 Alkalis on sinapine. 
 Spartium scoparium, L. (Cytisus scopa- 
 
 riiis, Linck.) 
 Strychnosnux vomica, S.Ignatii, S. colu- 
 
 brina. 
 
 Bone-oil. 
 Opium. 
 
 Cacao-beans. 
 
 Ammonia and hydrosulphuric acid on 
 
 acetone. 
 Hydrosulphuric acid on aldehydam- 
 
 monia. 
 Ammonia on sulphocyanate of allyl (oil 
 
 of mustard.) 
 
 Ethylamine on sulphocyanate of allyl. 
 Keduction of nitrotoluene. 
 
 Hydrosulphuric acid on yaleral ammonia. 
 
 Veratrum album. 
 
 Cliloride of ethylene on ammonia. 
 
 2. Alkaloids comparable to hydrate of ammonium, forming salts by combining with 
 acids and eliminating water. 
 
 C 10 H 25 NO. 
 
 Naine. Formula. 
 
 Amylium. 
 
 Hydrate of Methyldiethylamylium .... 
 ,, Tetramylium ..... 
 
 Triethylamylium C S1 H 27 NO. 
 
 Brucium. 
 
 Hydrate of Ethylbrucium 
 
ALKALOIDS. 125 
 
 Name. Formula. 
 
 Oonium. 
 
 Hydrate of Diethylconium C 12 H 25 NO. 
 
 Methylethylconium C n H 23 NO. 
 
 Ethylenium. 
 
 Hydrate of Trimethylethylenium C 5 H 1S NO. 
 
 Ethylium. 
 
 Hydrate of Methyltriethylium C 7 H 19 NO. 
 
 Tetrethylium C^'NO. 
 
 Methylium. 
 
 Hydrate of Tetramethylium C 4 H 13 NO. 
 
 Nicotium. 
 
 Hydrate of Ethylnicotium C 7 H 13 NO. 
 
 Methylnicotium OT^NO. 
 
 Phenylium. 
 
 Hydrate of Ethyltriphenylium C 20 H 21 NO. 
 
 Methylethylamyjophenylium . . . C H H 25 NO. 
 
 Triethylphenylium C 12 H 21 NO. 
 
 Piperylium. 
 
 Hydrate of Diethylpiperylium C 9 H 21 NO. 
 
 Pyridine. 
 
 Hydrate of Ethylpyridine C 7 HNO. 
 
 Strychnium. 
 
 Hydrate of Amylstrychnium C 26 H 34 N 2 3 . 
 
 Ethylstrychnium C* 3 H 28 N*0 3 . 
 
 Tolylium. 
 
 Hydrate of Triethyltolylium C 13 H 23 NO. 
 
 There are some substances not included in the above list, such as acetamide, 
 C 2 H 5 NO, acetonitrile, C 2 H 3 N, &c., which possess the most important properties of 
 alkaloids to quite as great an extent as some of the bodies there enumerated, but 
 which, in most of their relations, are associated with other well denned groups of com- 
 pounds, and are in consequence seldom classed among alkaloids. On the other hand, 
 this list contains some bodies, such as urea and its derivatives, which also find their 
 places in other classes, but which had long been regarded solely as alkaloids before 
 their relations to other compounds were discovered. This inconsistency is unavoidable. 
 There is not in nature any sharp distinction between alkaloids and other substances ; 
 hence, in determining whether particular bodies ought, or ought not, to be classed as 
 alkaloids, we must sometimes decide by reference to customary usage, or other circum- 
 stances equally arbitrary. G-. C. F. 
 
 Alkaloids, detection of, in chemico-legal investigations. The certain 
 detection of the poisonous alkaloids in chemico-legal investigations involves their sepa- 
 ration, in a state of purity, from the substances with which they are mixed. When, 
 as is often the case, a very small quantity of an alkaloid is contained in a large quan- 
 tity of a complicated mixture of animal or vegetable matter, its accurate separation 
 is a problem of considerable difficulty. The first chemist who gave a systematic 
 method of proceeding in such cases was Stas (Bulletin de 1' Academic Eoyale de Mede- 
 cine de Belgique, xi. 304 (1851) ; Ann. Ch. Pharm. Ixxxiv. 379 ; J. Pharrn. Chim. xxii. 
 281), and the method which he proposed continues to be the one most generally 
 employed. His process consists in the successive and systematic use of various 
 solvents, such as dilute acids, alcohol, and ether. 
 
 The method of carrying it out is as follows : When an alkaloid has to be sought for 
 among the contents of the stomach or intestines, the substances to be examined are 
 treated with twice their weight of pure absolute alcohol, to which from 0'5 gramme to 
 2 grammes of tartaric or oxalic acid (the former is preferable) have been added, and 
 the mixture is heated in a flask to between 70 and 75 C. (When an entire organ, 
 such as the liver, heart, or lungs, has to be examined for an alkaloid, it must first be 
 divided as finely as possible, then moistened with pure absolute alcohol, squeezed, and 
 afterwards washed with alcohol till all the soluble constituents are removed. The 
 liquid thus obtained is treated in the same way as a mixture of suspected matter and 
 alcohol.) When quite cold, the mixture is filtered, the insoluble part washed with 
 strong alcohol, and the alcoholic solution evaporated either in vacuo, or in a rapid 
 current of air at a temperature not exceeding 35 C. 
 
 If the residue left on evaporating the alcohol contains fat or other insoluble matter, 
 
126 ALKALOIDS. 
 
 it must be filtered again through a filter wetted with distilled water, the filtrate must 
 be evaporated nearly to dryness in vacuo over sulphuric acid, and the residue ex- 
 hausted with cold absolute alcohol. The alcoholic solution is once more evaporated 
 at the atmospheric temperature, either in the air, or better in vacuo, and the acid 
 residue of this evaporation is dissolved in the smallest possible, quantity of water. To 
 the solution so obtained, pure, powdered acid carbonate of potassium or of sodium is 
 added very gradually until there is no more effervescence. The neutralised solution 
 is shaken with from four to five times its bulk of pure ether, and then allowed to settle. 
 When the layer of ether has become perfectly clear, a little of it is decanted into a 
 glass capside, and left to. spontaneous evaporation in a very dry place. If, after the 
 evaporation of the ether, slight streaks of liquid appear on the side of the capsule, 
 and run together slowly to the bottom of it, a liquid and volatile alkaloid is probably 
 present. If this be the case, the warmth of the hand will be sufficient to cause the 
 contents of the capsule to exhale a disagreeable smell which, according to the nature 
 of the alkaloid, is more or less sharp, choking, and irritating. If these indications 
 are wanting, the alkaloid, if any is present, is probably solid and non-volatile. Ac- 
 cording to the nature of the alkaloid, as indicated by this preliminary trial, Stas 
 recommends different processes for its further purification. 
 
 A. The alkaloid is liquid and volatile. In tnis case 1 or 2 cub. cent, of strong 
 solution of caustic potash or soda are added to the contents of the flask, from which 
 the small quantity of the ethereal solution was taken, and the whole is again well 
 shaken. After standing for a sufficient time, the ether is poured off, and the residue 
 is again shaken three or four times with fresh quantities of ether. The ethereal 
 liquids so obtained, containing the alkaloid in solution, are united and shaken with 
 1 or 2 cub. cent, of a mixture of 4 parts by weight of water and 1 part of sulphuric 
 acid ; after being allowed to stand, the ether is poured off, and the acid liquid is 
 washed with a second quantity of ether. 
 
 As the sulphates of the volatile alkaloids are soluble in water, but almost all 
 insoluble in ether, the alkaloid sought is contained in the dilute sulphuric acid, in the 
 form of pure sulphate *, while the animal matter which the ether may have taken up 
 from the alkaline liquid together with the alkaloid, remains still dissolved by it. 
 
 In order to obtain the alkaloid from the solution of its sulphate, the latter is mixed 
 with a strong solution of caustic potash or soda; the mixture is well shaken, and then 
 exhausted with pure ether, which dissolves the alkaloid together with ammonia. The 
 ethereal solution is allowed to evaporate f at as low a temperature as possible, and 
 in order to remove from the residue the last traces of ammonia, the vessel containing 
 it is placed for an instant in vacuo over sulphuric acid. The alkaloid then remains 
 in a state of purity, with its characteristic chemical and physical properties. 
 
 B. The alkaloid is solid and fixed. If on evaporating a small quantity of the ether 
 with which the liquid neutralised by acid carbonate of sodium has been mixed (see 
 above), there is no sign of the presence of a volatile alkaloid, the liquid must be fur- 
 ther examined for fixed alkaloids as follows. Caustic potash or soda is put into the 
 flask containing ether and the neutralised solution, the mixture is again vigorously 
 shaken, the ethereal layer is poured off as soon as it is clear, and the watery alkaline 
 liquid is several times washed with a considerable quantity of fresh ether. The ether 
 now contains the free alkaloid in solution J, and on evaporation leaves either a solid 
 residue or a colourless milky liquid containing solid particles in suspension. The 
 smell of this residue is disagreeably animal, but not sharp ; it colours red litmus-^ 
 paper permanently blue. 
 
 In order to obtain the alkaloid in the crystalline state, a few drops of alcohol are 
 poured into the capsule containing it and allowed to evaporate. Usually, however, 
 it is still too impure to crystallise in this way. When this is the case, a few drops of 
 water made very slightly acid by sulphuric acid, are poured upon the residue left by 
 the evaporation of the alcohol, and made to come in contact with the whole of it by 
 properly inclining the capsule in various directions : the alkaloid is thus dissolved, 
 while the fatty impurities remain adhering to the capsule. The acid solution, which, 
 if the last operation has been well performed, is clear and colourless, is poured off, the 
 capsule is washed with a few drops more of the acid water, the washings are mixed 
 with the first solution, and the whole is evaporated over sulphuric acid to about 
 three quarters of its bulk. A saturated solution of pure carbonate of potassium 
 
 * Sulphate of conine being not quite insoluble in ether, a little of this alkaloid may remain in the 
 ethereal solution ; tin- greater part, however, is always in the aqueous acid solution. 
 
 t If conine be; present, a great part of it will evaporate with the ether. 
 
 j If morphine has to be sought for ihe liquid should be shaken with ether immediately after being 
 neutralised with rarbonate of sodium, and the ether should be po red off as quickly a- possible, for, if 
 the alkaloid have time to separate in the crystalline form, scarcely any of it is dissolved hy the ether, 
 (Otto.) 
 
ALKALOIDS. 127 
 
 is added TO the remaining liquid, and the mixture is treated with absolute alcohol, 
 which dissolves the liberated alkaloid, but leaves undissolved the sulphate and 
 excess of carbonate of potassium. On evaporating the alcoholic solution, the alkaloid 
 is obtained crystallised, and in a state to show its characteristic reactions. 
 
 According to Otto (Ann. Ch. Pharm. c. 39) the above process of purifying the 
 fixed alkaloids may be advantageously modified as follows. Instead of decomposing 
 the impure tartrate or oxalate by acid carbonate of potassium or sodium, and obtain- 
 ing a solution of the free alkaloid in ether, as described in the first part of this 
 article, the salt dissolved in a small quantity of water is washed with ether, as long as 
 the ether is coloured by it and leaves a residue on evaporation, and afterwards the 
 solution is neutralised by carbonate of sodium and ether added to dissolve the 
 alkaloid as already described. On evaporating the ethereal solution thus prepared, 
 the alkaloid is left in a state of great purity. Or, the acid sulphate of the alka- 
 loid may be formed and washed with ether, as in the process for purifying a volatile 
 alkaloid. 
 
 Another method of detecting and separating the organic alkaloids from mixtures of 
 other substances has been given by Sonnenschein (Ann. Ch. Pharm. civ. 45). 
 This method is founded upon the property which the alkaloids possess, in common 
 with ammonia, of giving precipitates in an acid solution of phosphomolybdate of 
 sodium : it is very easy of execution, and seems to give very accurate results. 
 
 Phosphomolybdate of sodium is thus prepared. The yellow precipitate obtained 
 by mixing acid solutions of molybdate of ammonium and phosphate of sodium is 
 well washed, suspended in water, and heated with carbonate of sodium till it is 
 completely dissolved. The solution is evaporated to dryness, and the residue ignited 
 till all ammonia is expelled : if any reduction of molybdic acid take place during 
 the ignition, the product is moistened with nitric acid and again ignited. It is then 
 heated with water, nitric acid added till the solution has a strongly acid reaction, 
 and the gold-yellow solution thus obtained is diluted till 10 parts of the solution 
 contain 1 part of solid residue. It must be carefully preserved from contact with 
 ammonia. 
 
 This reagent is applied to the separation of the alkaloids in the following manner. 
 The whole of the organic matter to be examined is repeatedly exhausted with very 
 dilute hydrochloric acid : the extract is evaporated at a heat of 30 C. to the consis- 
 tence of a thin syrup, then diluted, and left for some hours in a cool place before 
 filtration. The filtrate is precipitated by excess of phosphomolybdic acid, the precipi- 
 tate collected on a filter, thoroughly washed with water containing phosphomolybdic 
 and nitric acids, and introduced while moist into a flask. Caustic baryta is added, 
 to a distinct alkaline reaction : and the flask having been fitted with a delivery- 
 tube which is connected with a bulb-apparatus containing hydrochloric acid, heat is 
 gradually applied, when the ammonia and volatile organic bases distil over, and are 
 collected in the hydrochloric acid. The residue in the flask (containing the non- 
 volatile alkaloids) is freed from excess of baryta by a current of carbonic anhy- 
 dride, carefully evaporated to dryness, and extracted with strong alcohol. On 
 evaporating the alcoholic solution, the bases are commonly obtained in a state 
 of such purity that they will at once exhibit their characteristic reactions : occa- 
 sionally, however, they require to be further purified by recrystallisation from alcohol 
 or ether. 
 
 A process has been employed by Graham and Hofmann (Chem. Soc. Qu. J. v. 
 173 ; Ann. Ch. Pharm. Ixxxiii. 39; Pharm. J. Trans, xi. 504) for the detection of 
 strychnine in beer, which might doubtless be employed with equal advantage for the 
 detection of other alkaloids in large quantities of liquid. It consists in leaving the 
 liquid to be examined in contact with about a fortieth of its weight of good animal 
 charcoal for a day, the whole being frequently shaken, collecting the charcoal on a 
 filter, washing it once or twice with water, and then boiling it for half an hour with 
 alcohol, which dissolves out the alkaloid. The alcoholic solution is evaporated, 
 the residue is made alkaline by the addition of a few drops of potash or soda, and 
 then shaken up with ether, which, when poured off and evaporated, leaves the organic 
 base with its characteristic properties. 
 
 Schulze (Ann. Ch. Pharm. cix. 177) has indicated the acid liquid obtained by 
 dropping pentachloride of antimony into aqueous phosphoric acid as a very delicate 
 reagent for certain alkaloids, and as a substance which may probably serve for the 
 separation of the alkaloids in general. 
 
 When an alkaloid has been separated in a state of purity by one of the above 
 processes^ or by any other, its chemical and physical properties must be carefully 
 observed in order to determine its individual character, and the reactions obtained 
 should in every case be controlled by comparison with those given by a pure speci- 
 men of the substance suspected. 
 
128 ALLANTOIC AND AMNIOTIC LIQUIDS. 
 
 From what has been stated above relative to the absorption of the alkaloids by 
 animal charcoal, it is evident that that substance should never be employed to 
 decolorise a solution previous to its being examined for poisonous organic bases. The 
 employment of basic acetate of lead for the same purpose should also be avoided, 
 since it not only introduces a poisonous metal into the substance to be examined, but 
 the sulphuretted hydrogen, which is required to remove the lead, is apt to combine 
 with some of the organic matters present, forming compounds which, in contact with 
 the air, give rise to highly coloured and disagreeably smelling products, very difficult 
 afterwards to get rid of. (Stas.) 
 
 For further details concerning modifications of Stas's process, and for some methods 
 which are not mentioned in this article, the reader is referred to the article on the 
 same subject in Liebig, Poggendorff, and Wohler's " Handworterbuch der reinen und 
 angewandten Chemie," 2nd edition, i. 464 ; and for the reactions of the individual 
 alkaloids, to the various articles in this Dictionary in which they are specially de- 
 scribed. G. C. F. 
 
 The commercial name of two different plants. True alJcanet con- 
 sists of the leaves and roots of the Lawsonia inermis, which grows wild in the Levant. 
 The leaves pulverised and made into a paste with water yield a yellow dye. The 
 root, which contains a red pigment, is used as a cosmetic. 
 
 False alJcanet (Orcancttc, Radix alcannce spurice) is the root of Anchusa titic- 
 toria, which grows in France, Spain, Italy, Hungary and Greece. It is inodorous, 
 has a faint, somewhat astringent taste, and colours the saliva. It is used in dyeing 
 to produce a very brilliant violet and a grey ; and for this purpose, linen or cotton 
 goods previously prepared with alum-mordants for violet, and with iron-mordants for 
 grey, are dipped in an alcoholic extract of the root. It is also used for dyeing silk, 
 but not for wool. The colouring matter is called Anchusin (which see). 
 
 AXiXARGEN and AXiKARSXlff. (See AESENIDES OF METHYL.) 
 
 AXiXiAGXTE. A mineral which appears to be an intimate mixture of hornstone 
 and silicate of manganese, perhaps also with carbonate of manganese. 
 
 Syn. of DIOPSIDE and ATJGITE. 
 AX.X.ANXTX:. (See ORTHITE.) 
 
 ALXiANTOXC and AlttlUIOTIC LIQUIDS. The foetus of most mammi- 
 ferous animals is enveloped in two membranes, the outer of which is called the 
 allantois, and the inner the amnium. The space between the two is connected by a 
 duct with the urinary bladder of the foetus, and contains a liquid called the allantoic 
 liquid, which is in fact the urine of the foetus. The amnium at first lies close upon 
 the foetus, but gradually separates and becomes filled with a liquid in which the 
 foetus floats suspended by the umbilical cord. This liquor is the liquor amnii. 
 
 The allantoic liquid is especially distinguished by containing allantoin, together 
 with albumin, alkaline lactates, chloride of sodium and phosphates, and sometimes 
 glucose. The amniotic liquid contains albumin, pyin, a substance resembling mucus, 
 extractive matter, and in some instances glucose, together with alkaline chlorides, 
 sulphates and phosphates. 
 
 These liquids have been investigated by many distinguished chemists, but the most 
 exact analyses of them are those which have been recently made by Schlossberger 
 (Ann. Ch. Pharm. xcvi. 67, and ciii. 193), and by Majewski (Dissert, de Substan- 
 tiaram, &c., Dorpat, 1858; J. pr. Chem. Ixxvi. 99), Majewski's results are as 
 follows : 
 
 Both liquids, in the earlier stages of development of the embryo of cows and sheep, 
 are clear and colourless : at a later stage, the amniotic liquid of the cow becomes 
 gummy and yellowish, also turbid ; in sheep and swine on the contrary, it always 
 remains clear and colourless, and never becomes gummy. The allantoic liquid 
 becomes yellower with age, and at last reddish yellow, but remains clear, excepting 
 in swine, in which it is always turbid. Both liquids generally exhibit an alkaline 
 reaction. 
 
 In both liquids, the solid constituents, organic and inorganic, increase for the most 
 part in quantity as the development of the foetus progresses. In the human foetus, how- 
 ever, the quantity of solid matter in the amniotic liquid decreases considerably towards 
 the time of birth (see table). The same result was obtained by Vogt and by Scherer. 
 the latter of whom found 2*416 per cent, of solid constituents in the amniotic liquid 
 in the fifth month of gestation, and only 0'852 at birth. 
 
 The amniotic liquid retains its albumin up to the period of maturity of the foetus. 
 but (as appears from investigations on the human embryo) this amount decreases in 
 the later period of the development of the embryo, and this diminution appears to be 
 
ALLANTOIC AND AMNIOTIC LIQUIDS. 
 
 129 
 
 connected with the formation of the placenta. In the amniotic liquid of the cow, the 
 albumin may be recognised by its ordinary properties in the earlier stages of develop- 
 ment, but afterwards the liquid becomes gummy and no longer exhibits the usual 
 reaction with nitric acid. The same result was obtained by Schlossberger, (p. 130). 
 
 The allantoic liquid increases in quantity and consistence as the development of 
 the embryo advances ; it is always clear (excepting in swine) and resembles saturated 
 urine. The allantoic liquid of swine contains iron and a peculiar compound of lime 
 and albumin. 
 
 In both liquids, the quantity of sugar gradually increases from the earliest period 
 of foetal life, and is greatest a short time before birth. Sugar appears however to be 
 present only in the vegetable feeders : in human embryonic liquids it cannot be 
 detected. 
 
 The quantity of inorganic salts increases as development advances. Both liquids 
 contain chlorides, phosphates and sulphates, the quantity being greater in the 
 allantoic than in the amniotic liquid. 
 
 The following table exhibits a summary of the quantitative results obtained by 
 Majewski: 
 
 In 100 parts. 
 
 
 Period of 
 Development. 
 
 Amnios 
 Allantois 
 
 ' 
 
 cent. 
 
 / 
 
 Spec, 
 grav. 
 
 Water. 
 
 Solid 
 sub- 
 stance. 
 
 Or- 
 ganic. 
 
 Inor- 
 ganic. 
 
 Albu- 
 min. 
 
 Sugar. 
 
 Urea. 
 
 P2O5 
 
 A 
 S03 
 
 Week 3-4 { 
 
 27 
 
 1-0029 
 
 99-357 
 
 0-643 
 
 0-459 
 
 0-184 
 
 
 0-243 
 
 
 
 
 
 <- { 
 
 Amnios 
 Allantois 
 
 19 
 63 
 
 1-0018 
 1 0066 
 
 99-460 
 98-980 
 
 0-540 
 1-020 
 
 0-100 
 0-650 
 
 0-140 
 0-370 
 
 0-105 
 
 0-063 
 0-241 
 
 0-20 
 0-40 
 
 0-0047 
 
 0-0052 
 
 Embryo 
 of Sheep. 
 
 6J-9 { 
 
 Allantois 
 
 62 
 59 
 
 1-0047 
 1-008V 
 
 98-945 
 98-127 
 
 1-055 
 1-873 
 
 0-685 
 1-198 
 
 0-370 
 0-675 
 
 0125 
 
 0-114 
 
 0-449 
 
 0-302 
 0-500 
 
 0-0078 
 0-03.% 
 
 0-0061 
 0-11069 
 
 
 10-12J { 
 
 Amnios 
 Allantois 
 
 163 
 119 
 
 1-0069 
 1-0 100 
 
 98-51/i 
 97-453 
 
 1-485 
 2-547 
 
 0-917 
 1-671 
 
 0-5S8 
 
 0-87ti 
 
 0-170 
 
 0-172 
 0-642 
 
 0-370 
 0606 
 
 0-0 14S 
 0-013? 
 
 0-0054 
 0'0<!75 
 
 
 12|_18 { 
 
 .Amnios 
 Allantois 
 
 657 
 335 
 
 1-0064 
 1-0097 
 
 98-660 
 97-380 
 
 1-340 
 2-620 
 
 0-905 
 0-960 
 
 0-435 
 0-660 
 
 0-241 
 
 0-196 
 0-6C.7 
 
 0-475 
 0-780 
 
 0-0827 
 0-OW8 
 
 0-006 
 0-U326 
 
 
 9-12 { 
 
 Amnios 
 Allantois 
 
 675 
 95 
 
 1 -0047 
 1-010 
 
 98-970 
 J7-5HI 
 
 1-03 
 
 2-69 
 
 0-600 
 1-800 
 
 0-150 
 0-890 
 
 0-032 
 
 0-104 
 0-555 
 
 0-200 
 0-330 
 
 0-018 
 0-060 
 
 0-009 
 0-033 
 
 Embryo 
 of Cow. 
 
 12-22 { 
 
 Amnios 
 Allantois 
 
 1624 
 643 
 
 1-006) 
 1-0125 
 
 98-554 
 'JS-85S 
 
 1-446 
 3-142 
 
 n-876 
 2-338 
 
 0570 
 0-804 
 
 0-097 
 
 0-191 
 0-605 
 
 0-5:98 
 0-645 
 
 0-0 ->1 
 0-022 
 
 0-022 
 0-097 
 
 
 21-27 { 
 
 Amnios 
 Allantois 
 
 698 
 1236 
 
 1-0075 
 1-0163 
 
 98-076 
 96-160 
 
 1-924 
 3-840 
 
 1-171 
 2-767 
 
 0-753 
 1-073 
 
 0-215 
 
 0-302 
 0-642 
 
 0-426 
 0-857 
 
 0-016 
 0-038 
 
 0-022 
 0-112 
 
 Human f 
 Embryo. ( 
 
 In the 2nd month 
 At birth . 
 
 Amnios 
 
 
 1-0049 
 
 95-405 
 98-490 
 
 3-595 
 1-510 
 
 0-95 
 
 5-600 
 
 2-288 
 0-357 
 
 none 
 none 
 
 0-380 
 
 
 
 ofSe { 
 
 Between six and ( 
 eight weeks \ 
 
 Allantois 
 
 60 
 18 
 
 1 -0064 
 1-OOS8 
 
 98-114 
 97-580 
 
 1-886 
 2-420 
 
 1-218 
 1-705 
 
 0-638 
 0-715 
 
 0-562 
 
 trace 
 trace 
 
 0-240 
 0-358 
 
 
 
 Schlossberger found in the embryonic liquid of cows the following quantities of 
 water and inorganic salts : The ages of the foetus were: of (a) 30 weeks ; (b) 18 
 weeks ; (c) 15 weeks ; (d) 78 weeks ; (e) 5 weeks, and (/) 3 weeks : 
 
 Amniotic 
 liquid. ~\ d. 
 
 Allantoic 
 liquid. 
 
 Water. 
 97-18 
 97*28 
 98-96 
 98-67 
 
 / 98-12 
 
 c. 97-33 
 
 e 98-76 
 
 /. 97-35 
 
 Ash. 
 
 0-72 
 1-02 
 
 0-89 
 
 0-93 
 0-73 
 0-71 
 
 Soluble 
 Saks. 
 
 0-694 
 1-00 
 
 0-86 
 
 0-91 
 0-70 
 
 Insoluble. 
 Salts. 
 
 0-026 
 0-02 
 
 0-03 
 
 0-02 
 0-03 
 
 The liquids, even in the fresh state, exhibited an alkaline reaction, and effervesced 
 briskly with acids : and they all exhibited the reactions of sugar, the amniotic liquid 
 of d containing 0-092 per cent, of that substance, and the allantoic liquid of the same, 
 0-454 per cent. Schlossberger did not find urea in the amniotic liquid. 
 
 The albuminoidal substances of both liquids exhibited differences of character 
 amongst themselves, and many unusual reactions, indicating the presence of com- 
 pounds intermediate between albumin casein, mucus and pyin. The reactions ob- 
 served by Schlossberger are given in the following table: 
 
 VOL. I. K 
 
130 
 
 ALLANTOIC AND AMNIOTIC LIQUIDS. 
 
 Appearance. 
 Keaction on 
 boiling and 
 on addition 
 of acetic acid. 
 
 Amniotic liquid of a and c. 
 
 Allantoic liquid of b and c. 
 
 a. Viscid like white of egg : 
 mixed easily with water, and 
 filtered readily. On boiling, 
 became more mobile, with 
 scarcely perceptible turbidity. 
 On neutralising with acetic 
 acid : scarcely perceptible tur- 
 bidity, the liquid remaining vis- 
 cid. On boiling, small flocks 
 separated. The greater part of 
 the protein-substance remained 
 dissolved. On evaporation : films. 
 b. Not viscid. Remained 
 perfectly clear when boiled, 
 either alone or with acetic acid. 
 
 b. Not viscid; clear on boil- 
 ing. Acetic acid produces 
 slight turbidity, and redissolves | 
 the flocks but slowly, even in ex- 
 cess and at the boiling heat. 
 c. Coagulates even when 
 boiled alone, the coagulum being 
 but partially soluble in acetic 
 acid. On evaporation : films. 
 Both b and c become very 
 turbid when boiled with chlo- 
 ride of calcium or sulphate of 
 magnesium, especially c. The 
 turbidity (arising in b most pro- 
 bably from carbonates) disap- 
 pears on adding acetic acid. 
 
 Alcohol. 
 
 a. Throws down flocks solu- 
 ble in warm water. 
 c. No change. 
 
 b. No change. 
 c. Turbidity. 
 
 Nitric acid. - 
 
 a. Slight turbidity, disappear- 
 ing with excess of acid. 
 c. No turbidity. Liquid does 
 not become yellow on boiling. 
 
 b. Scarcely perceptible turbi- 
 dity. 
 c. Precipitate and yellow 
 colour on boiling. 
 
 HgCL 
 
 a. Slight turbidity : small 
 flakes on boiling. 
 c. Turbidity. (WithN0 8 Hg: 
 copious precipitate). 
 
 b. No change. 
 c. Precipitate. 
 
 Ferrocyanide 
 of potassium. 
 
 a. No change. 
 c. Turbidity only after addi- 
 tion of acetic acid. 
 
 b. No change. 
 c. After acidulation : flocks. 
 
 Acetate of 
 lead. Basic 
 acetate of lead. 
 Tannin. 
 
 Copious precipitates. 
 
 Copious precipitates. 
 
 Alum. 
 
 No change in any instance. 
 
 r. C 4 H 8 N 4 S , or C 9 H 6 N*0^. Discovered by Vauquelin and 
 Buniva (Ann. Chim. xxxiii 269) in the amniotic liquid of the cow.* Lassaigne 
 (Ann. Ch. Phys. [2] xvii. 301) obtained it from the allantoic liquid of the cow, and 
 Wohler (Ann. Ch. Pharm. Ixx. 220) from the urine of calves. It is formed arti- 
 ficially by treating uric acid with water and peroxide of lead. (Liebig and Wohler, 
 Ann. Ch. Pharm. xxvi. 244.) 
 
 C 5 H 4 N 4 8 + H 2 + 2PbO = C 4 HN 4 3 + CPb ? 3 ; 
 
 Uric acid. Allantoin. Carbonate 
 
 of lead. 
 
 or with a mixture offerricyanide of potassium and caustic potash. (Schlieper, Ann. 
 Ch. Pharm. Ixvii. 216.) ' 
 C 5 H 4 N 4 8 + 2C 6 N 8 Fe 2 K: s + 4KHO = C 4 H 8 N 4 3 + CK 2 8 + 4C 3 N 3 FeK 2 + H 2 0. 
 
 Uric acid. 
 
 Ferriryanide of 
 potassium. 
 
 Allantoin. 
 
 Carbonate of 
 potassium. 
 
 Ferrocyanide 
 of potassium. 
 
 Preparation. Pulverised uric acid is suspended in water, nearly at the boiling heat, 
 and finely pounded oxide of lead is added by small portions, and with frequent stirring, 
 till the last portions no longer turn white. The liquid filtered while hot deposits on 
 
 As, however, subsequent experimenters have not been able to obtain it from that source, it is pro- 
 bable that the amniotic liquid was mixed with allantoic liquid. 
 
ALLANTOIN. 131 
 
 cooling, crystals of allantoin, while urea remains in solution, and oxalate of lead is 
 left on the filter. The two latter compounds are produced by the action of the excess 
 of peroxide of lead on the allantoin. (Liebig and Wohler.) 
 
 C 4 IPN 4 3 + 2PbO + H 2 = 2CH 1 N 2 + C 2 Pb 2 4 . 
 
 Urea. Oxalate of 
 
 lead. 
 
 To obtain allantoin from the allantoic liquid, the liquid is evaporated to a fourth of 
 its bulk, and the crystals which are deposited on cooling are decolorised with ani- 
 mal charcoal. From calves' urine, it is prepared by evaporating the liquid to a syrup, 
 and leaving it at least for several days, then diluting with water; washing the deposit 
 with water to separate a quantity of gelatinous matter, chiefly consisting of urate of 
 magnesium ; boiling the crystalline residue of allantoin and phosphate of magnesium 
 with water and animal charcoal ; filtering at the boiling heat ; and adding a few drops 
 of hydrochloric acid to the filtrate to retain in solution the small quantity of phos- 
 phate of magnesium dissolved in the boiling liquid. The allantoin is then deposited in 
 crystals on cooling. 
 
 Properties. Allantoin forms shining colourless prisms, having a vitreous aspect, and 
 belonging, according to Dauber (Ann. Ch. Pharm. Ixxi. 68), to the monoclinic system. 
 It is tasteless and without action -on vegetable colours. It dissolves in 160 pts. of 
 water at 20 C., and in 30 pts. of boiling water. Alcohol dissolves it in larger quantity. 
 
 Decompositions. By dry distillation, allantoin is resolved into carbonate and cyanide 
 of ammonium, a small quantity of empyreumatic oil and a very porous charcoal. When 
 gently heated with nitric or hydrochloric acid, it is converted into urea and allanturic 
 acid. (Pelouze, Gerhardt.) 
 
 C 4 H 6 N 4 8 + H 8 = CH 4 N 2 + C 3 H 4 N 2 3 
 
 Allanturic acid. 
 
 Heated with sulphuric acid, it is resolved into carbonic acid, carbonic oxide, and am- 
 monia. (Liebig and Wohler.) 
 
 C 4 H 6 N 4 3 + 3H 2 = 2C0 2 + 2CO + 4NH 3 . 
 Boiled with baryta water, it gives off ammonia and precipitates oxalate of barium : 
 
 C 4 H 6 N 4 3 + 4BaHO + H 2 = 4NH 3 + 2C 2 Ba 2 4 . 
 
 Similarly with aqueous potash (Liebig and Wohler). A solution of allantoin .in 
 cold potash deposits all the allantoin unaltered, if immediately mixed with acids ; but 
 in the course of a day or two, it changes spontaneously into hydantoate of potassium 
 (C 4 H 7 KN 4 4 ), and is then no longer precipitated by acids, gives off but little ammo- 
 nia when boiled, and does not form any oxalic acid : 
 
 C 4 H 6 N 4 3 + KHO = C 4 H 7 KN 4 4 ; 
 
 by the further action of the alkali, the hydantoate of potassium is resolved into urea 
 and lantanurate of potassium : 
 
 C 4 H'KN 4 4 = CH 4 N 2 + C 3 H 3 KN 2 3 . 
 
 When the aqueous solution of allantoin is "boiled with metallic oxides, compounds 
 are formed which may be called salts of allantoin. Some of them consist simply of 
 allantoin in which 1 at. H is replaced by a metal ; thus, the cadmium-compound is 
 C 4 H s CdN 4 O 3 : and the s//#er-compound, obtained by mixing a solution of allantoin 
 with nitrate of silver and then with ammonia, is C 4 IPAgN 4 O 3 . But most of them con- 
 tain an excess of the metallic oxide; thus, the zinc-compound is Zn 2 0.2C 4 H a ZnN 4 8 , 
 and the lead-compound Pb 2 0.4C 4 H 5 PbN 4 3 . These compounds are insoluble or 
 sparingly soluble in water, and decompose at 100 or a little above (Limpricht, 
 Ann. Ch. Pharm. Ixxxviii. 94). The silver-compound was obtained by Liebiyr and 
 Wohler. 
 
 When a solution of allantoin is boiled with excess of mercuric oxide, the filtrate 
 becomes milky on cooling, and after a while deposits an amorphous powder containing 
 Hg 2 0.3C 4 H 5 HgN 4 3 , or 5Hg0.3C s H 5 N*0 5 . Three other compounds are said to be 
 obtained from the mother-liquor. Allantoin does not precipitate corrosive sublimate ; 
 but with mercuric nitrate, in a cold and very dilute solution, it forms a precipitate 
 containing 3Hg 2 0.4C 4 H 5 HgN 4 3 , or dHgO.ICt&WO*. 
 
 On this last property is founded a method for the quantitative estimation of allan- 
 toin, by precipitation with a graduated solution of mercuric nitrate. The method is 
 similar to Liebig' s process for the estimation of urea (q. v.\ but is applicable to 
 the estimation of allantoin only in liquids not containing urea. To precipitate 
 100 grins, of dry allantoin, C 4 II <i N 4 3 , requires 172 grms. of mercuric oxide: conse- 
 quently 10 cub. cent, of a graduated solution of mercuric nitrate containing 0'770 gnu. 
 
 K 2 
 
132 ALLANTURIC ACID ALLOPHANIC ACID. 
 
 mercuric oxide, will precipitate 0*448 grin, allantoin. The liquid should contain a con- 
 siderable excess of the mercuric salt. 
 
 AX.X. AlffTUXtXC ACID. C 3 H 4 N 2 3 . A product of the decomposition of allantoin 
 under the influence of nitric acid, hydrochloric acid, or peroxide of lead (p. 131) : 
 also obtained by treating uric acid with nitric acid or chlorine. It is a white solid 
 body, slightly acid, deliquescent, nearly insoluble in alcohol, and yields by distilla- 
 tion a product containing hydrocyanic acid, with a bulky residue of charcoal. With 
 nitrate of silver and acetate of lead, it forms white bulky precipitates, soluble in 
 excess of these salts, and of allanturic acid. (Pelouze, Ann. Ch. Phys. [3] vi. 71.) 
 
 AXiXiXHVXOXrTXTX:. Arsenide of Antimony, (p. 371.) 
 
 AXiXiXTURXC ACID. C 3 H S N 2 2 ? Obtained by mixing an aqueous solution of 
 alloxantin with excess of hydrochloric acid, boiling the liquid rapidly down to a small 
 quantity, treating the pulverulent mixture of allituric acid and undecomposed alloxantin 
 with nitric acid to dissolve out the latter, and dissolving the residue in 15 or 20 pts. 
 of hot water. The solution on cooling deposits allituric acid in the form of a bulky 
 yellowish white powder. It dissolves in strong sulphuric acid, and is precipitated from 
 the solution by water. Its solution in ammonia yields allituratc of ammonium, by 
 spontaneous evaporation, in colourless shining needles. The acid is decomposed by 
 boiling with potash, with evolution of ammonia, (Schlieper, Ann. Ch. Pharm. 
 Ivi. 20.) 
 
 AX.X.XUM SATIVUTO. (Garlic.} 100 pts. of the ash of the fresh plant yield 0;54 
 p. c. ash, containing in 100 parts: 12'17 carbonic anhydride, 4'82 sulphuric anhydride, 
 2'18 phosphoric anhydride, 35-13 potash, a trace of soda, 2*75 chloride of sodium, 
 5-74 carbonate of calcium, 6'89 carbonate of magnesium, 30-09 basic phosphate of 
 calcium, 0*22 silica, and traces of the phosphates of magnesium and iron. 
 
 AXiI>OCHROXTE. A variety of garnet, fine-grained, massive, and of dark dingy 
 colour. (See GARNET.) 
 
 AZiXiOGONXTX*. Syn. with HERDEBITE. 
 
 AXiXiOMORFHXTE. Breithaupt's name for a mineral from Eudolstadt, which, 
 according to the analysis of Gerngross, appears to be merely sulphate of barium. 
 
 AXiXiOPHAXTE. A hydrated silicate of aluminium, of a blue and sometimes 
 green or brown colour, occurring massive, or in imitative shapes, in a bed of iron-shot 
 limestone, or greywacke slate in the forest of Thuringia. It is transparent or trans- 
 lucent on the edges, moderately hard, but very brittle. Fracture imperfectly con- 
 choidaL Lustre vitreous. Specific gravity 1'89. According to Stromeyer's analysis, it 
 contains 2T92 silver, 32'2 alumina, 3'06 ferric hydrate, 73 lime, 0'52 sulphate of 
 calcium, 3'06 carbonate of copper, and 4T30 water. Bunsen found in a specimen from 
 a bed of lignite near Bonn, nearly the same composition, with a slight admixture of 
 the carbonates of calcium and magnesium, but no copper. The mineral appears from 
 the analyses of Walchner, Berthier, Guillemin, and others, to vary considerably in 
 composition, but irrespective of foreign admixtures it agrees nearly with the formula 
 Al 4 3 .3Si0 2 + 5H 2 0. Schnabel (Jahresber. d. Chem. 1850, s. 731), has, however, 
 analysed several allophanes containing from 14 to 19 per cent, of oxide of copper. 
 
 p2TT3>J2r)2 > 
 
 AX-iOPHAiariCACID. C 2 H 4 N 2 3 = ^ 0. Ureo-carbonic acid. (Gm. 
 
 ix. 266 ; Gerh. i. 418.) By passing the vapour of cyanic acid into absolute alcohol, 
 Liebig and Wohler obtained in 1830 a peculiar ether, which they regarded as cyanate 
 of ethyl; but in 1847 (Ann. Ch. Pharm. lix. 291), they discovered that the substance 
 thus formed was the ether of a peculiar acid which they called allophanic acid. 
 This acid contains the elements of 2 at. cyanic acid and 1 at. water : 
 C 2 H 4 N 2 3 = 2CHNO + IPO. 
 
 Its ethers are produced when the vapour of cyanic acid comes in contact with the 
 corresponding alcohols, and these ethers, treated with caustic alkalis, yield the cor- 
 responding salts of allophanic acid. The acid itself is not known in the separate state ; 
 when its salts are decomposed by a stronger acid, it is resolved into carbonic anhydride 
 and urea : 
 
 C 2 H 4 N 2 S = CO 2 + CH 4 N 2 0. 
 
 In like manner the salts when heated in the state of aqueous solution, are resolved into 
 carbonic anhydride, a carbonate, and urea. 
 
 Allophanate of Barium. Obtained by dissolving allophanate of methyl or ethyl in 
 baryta-water, whereby wood-spirit or alcohol is set free. The best method is to tri- 
 
 turate allophanate of ethyl with crystals of hydrate of barium and baryta- water, without 
 applying heat, till the ether disappears ; filter from the remaining bary 
 
 remaining baryta-crystals ; and 
 
ALLOPHANIC ETHERS. 133 
 
 set aside the filtrate for some days in a closed vessel ; the barium-salt then separates 
 gradually in hard crystalline nodules and crusts. The crystals are separated from 
 the vessel under the liquid ; the liquid quickly decanted ; any carbonate of barium 
 that may have been formed, is separated by elutriation ; and the crystals are washed a 
 few times with a small quantity of cold water, and dried on paper at the temperature of 
 the air. 
 
 The barium-salt has an alkaline reaction. When heated alone, it does not 
 give off a trace of water, but evolves monocarbonate of ammonium, and leaves cyanate 
 of barium. Its aqueous solution becomes turbid below 100 C., gives off carbonic 
 anhydride with effervescence, deposits all the baryta in the form of carbonate, and 
 afterwards contains nothing" but urea in solution : 
 
 2C 2 H 3 BaN 2 3 + IPO = C0 3 Ba 2 + CO 2 + 2CH 4 N 2 0. 
 
 This salt, when an acid is poured upon it, is decomposed with brisk effervescence, 
 yielding carbonic anhydride and urea ; even carbonic acid produces this decomposition, 
 though slowly ; neither cyanic acid nor ammonia is formed. 
 
 AUophanate of Calcium. Prepared like the barium-salt. Crystallisable. Sparingly 
 soluble in water. 
 
 AUophanate of Potassium. A solution of allophanic ether in alcoholic potash quickly 
 deposits this salt in laminae resembling those of chlorate of potassium. 
 
 AUophanate of Sodium. Obtained like the potassium-salt, or by triturating the 
 barium-salt, without application of heat, with an equivalent quantity of aqueous sul- 
 phate of sodium, and pouring alcohol upon the filtrate, which causes the sodium-salt to 
 crystallise out in small prisms having an alkaline reaction. The aqueous solution of 
 the salt evaporated without heat in vacuo, leaves the salt in the form of an iridescent 
 gelatinous mass ; evaporated between 40 and 50 C. it leaves the salt partly un de- 
 composed, partly resolved into urea and carbonate of sodium. The aqueous solution 
 mixed with nitric acid gives off carbonic anhydride and deposits shining scales of 
 nitrate of urea. It does not precipitate chloride of barium, in the cold, but, when 
 heated with it, forms an immediate precipitate of carbonate of barium. 
 
 Allophanic Ethers. These compounds contain the elements of 2 at. cyanic acid, 
 and 1 at. of an alcohol, monatomic, diatomic, or triatomic, e. g. 
 
 AUophanate of Ethyl . . . C 4 H 8 N 2 3 = 2CNHO + C 2 H 6 
 AUophanate of Ethylene . . C 4 H 8 N 2 4 = 2CNHO + C 2 H 6 2 
 AUophanate of Glyceryl . . C 5 H 10 l!s-0 5 = 2CNHO + C 3 H: 8 3 
 
 They are obtained by passing the vapour of cyanic acid into the alcohols. 
 
 AUophanate of Amyl, C 7 H"N 2 3 = C 2 H 3 (C 5 H U )N0 3 . Amylic alcohol rapidly 
 absorbs the vapours produced by the action of heat on cyanuric acid, the liquid, after 
 a while, solidifying into a magma of crystals, which may be purified by solution in 
 boiling water. (Schlieper, Ann. Ch. Pharm. lix. 23.) 
 
 AUophanate of amyl forms nacreous scales, unctuous to the touch, and without taste 
 or odour. It is insoluble in cold water, and its solution in hot water is neutral to 
 vegetable colours, and does not precipitate metallic salts. It is very soluble in alcohol 
 and in ether, and is precipitated from the solutions by water. It is not attacked by 
 chlorine, bromine, nitric acid, or hydrosulphuric acid. It melts at a gentle heat, and 
 sublimes without alteration ; but its melting-point is very near that at which decom- 
 position takes place. When heated above 100 C. it boils, gives off vapours of amylic al- 
 cohol, and leaves a residue of cyanuric acid, 3C 7 H 14 N 2 0* = 3C*H I2 + 2C 3 N'H 3 S . 
 Distilled with fixed alkalis, it gives off amyl-alcohol (Schlieper). According to 
 Wurtz (Compt. rend. xxix. 186), hot potash-ley converts it into carbonate of potassium, 
 amylamine, and ammonia : 
 
 C 7 H i4 N 2 3 + 4KHO = 2C0 3 K 2 + C 5 H I3 N + NH 3 + H 2 0. 
 
 AUophanate of Ethyl.ov Allophanic Ether, C 4 H 8 N 2 3 = C 2 H 3 (C 2 H 5 )N 2 3 . When 
 the vapours evolved from heated cyanuric acid are passed into absolute alcohol, 
 the liquid becomes very hot and gradually deposits crystals of aUophanic ether. The 
 product is washed with a small quantity of alcohol, then dissolved in a mixture of alcohol 
 and ether, and left to crystallise by evaporation (Liebig and Wohler, Ann. Ch. 
 Pharm. Iviii. 2GO ; lix. 291). According to Debus, aUophanic ether is likewise produced 
 by the action of ammonia on dicarbonate of ethylic di sulphide. 
 
 Allophanic ether crystaUises in colourless transparent needless, having a strong lustre. 
 It is insoluble in cold water, but dissolves in boiling water and in alcohol, sparingly in 
 ether. The solutions are neutral to test-papers, have no taste, and do not precipitate 
 metallic salts. 
 
 The ether dissolves in ammonia somewhat more freely than in water, and crystallises 
 
 K 3 
 
134 ALLOPIIANIC ETHERS. 
 
 therefrom, apparently free from ammonia. It dissolves in dilute sulphuric and nitric 
 acid at the boiling heat, apparently without decomposition. 
 
 The crystals when heated in an open vessel melt and volatilise, the vapours con- 
 densing in the air in woolly flocks. 
 
 Treated with cold alcoholic potash or baryta- water, it yields a metallic allophanate 
 and alcohol ; with a boiling solution of potash, it forms cyanurate of potassium. 
 
 Allophanate ofEthylene, C 4 H 8 N 2 4 = ^H^-H^ 2 ' Allo P hanate f Glycol.-^ 
 Grlycol (hydrate of ethyl one) absorbs cyanic acid vapour with considerable force, so 
 that it is best to cool the liquid during the absorption. The product is a white mass 
 which dissolves in boiling alcohol, and separates on cooling in colourless shining 
 laminae. It is soluble in water, and melts at 100 C. without decomposition, to a clear 
 colourless liquid, which solidifies in the crystalline form on cooling. At a stronger 
 heat, it gives off carbonate of ammonium, and a thick viscid liquid, while cyan uric acid 
 remains behind. Strong acids decompose it. With hydrate of barium, it behaves like 
 the glycerin-compound next to be described ; also with alcoholic potash. Strong 
 aqueous potash Likewise decomposes it, without formation of cyanuric acid. (Baeyer, 
 Ann. Ch. Pharm. cxiv. 160.) 
 
 P 2 TT 3 N 2 O 2 ) 
 
 Allophanate of Glyceryl, C 5 H'N 2 5 = H 2 (C^IP)'" [ 8 ' ^ttophanate of Gly- 
 cerin. Glycerin absorbs cyanic acid vapour, and is thereby converted into a white 
 sticky mass, which dissolves in alcohol, leaving only a small quantity of cyamelide. 
 The hot saturated solution, on cooling, deposits allophanate of glyceryl in hard crusts, 
 composed of small translucent nodules. The crystallisation is often slow, especially 
 when much glycerin is present ; hence it is best to wash the crude product with cold 
 alcohol before dissolving it in hot alcohol. The nodules, after recrystallisation from 
 alcohol and drying at 100, gave by analysis 3 3 -6 per cent, carbon, 57 hydrogen, and 
 15-5 N, the formula requiring 337 C, 5-6 H, and 157 N. 
 
 Allophanate of glyceryl has neither taste nor smell, dissolves slowly but abundantly 
 in water, and with tolerable facility in boiling alcohol. Heated in the dry state, it 
 melts at about 160 C. to a colourless liquid, which solidifies in a gelatinous mass on 
 cooling. On raising the temperature, a large quantity of carbonate of ammonium is 
 evolved, and the mass ultimately turns brown and emits an odour of burnt horn. 
 
 It is not decomposed by dilute adds at ordinary temperatures, but strong nitric and 
 sulphuric acids decompose it, with evolution of carbonic anhydride. 
 
 When triturated with water and hydrate of barium, it dissolves with facility ; but 
 the clear filtered solution deposits, after a short time, a bulky crystalline precipitate of 
 carbonate of barium. The precipitation takes place even when the quantity of baryta 
 is less than sufficient to saturate the allophanic acid present, so that it does not appear 
 possible to prepare allophanate of barium in this manner. A certain quantity of that 
 salt appears, however, to be formed, inasmuch as the liquid, after long standing, still 
 deposits carbonate of barium when heated. If alcohol be added to the liquid containing 
 an insufficient quantity of baryta, allophanate of ethyl is produced, probably by a 
 catalytic action. Allophanate of glyceryl heated with baryta- water, yields nothing but 
 carbonate of barium, urea, and glycerin. 
 
 In an alcoholic solution of potash, allophanate of glyceryl cakes together to a sticky 
 mass, then gradually dissolves, the solution after a while depositing long needles 
 which gradually change to small bulky masses of needles, apparently consisting of 
 ethyl-carbonate of potassium. (Baeyer.) 
 
 Allophanate of Methyl, C S HN*0 = C 2 H 3 (CH 3 )N 2 3 . Discovered by Ri chard- 
 son in 1837 (Ann. Ch. Pharm. xxiii. 128), and originally called ureo-carbonate of 
 methyl. When cyanic acid vapour is passed into methyl-alcohol, colourless crystals are 
 obtained, which must be repeatedly washed with water, and then dried at 100 C. When 
 heated, they partly volatilise undecomposed, and are partly resolved into ammonia, 
 methylene gas (?), carbonic anhydride, and cyanuric acid : 
 
 3C 3 H 6 N 2 8 - SNIP + 3CH 2 + 3C0 2 + O'H 3 N 3 3 . 
 
 Heated with potash, they are decomposed in the same manner as the ethyl-compound. 
 They dissolve readily in water, wood-spirit, and alcohol, especially when heated, 
 forming neutral solutions. 
 
 Allophanate of Eugenic acid, C 12 H 14 N 2 4 = C 2 H 3 (C 10 Hp)N 2 3 . Eugenic 
 acid rapidly absorbs cyanic acid vapour, forming a thick mass, which dissolves in hot 
 alcohol and separates in long shining needles on cooling. At 100 C. it gave 57'0 
 57-9 per cent. C, 57 5-9 H, and 11-3N (calc. 57'6 C, 5-6 II and 11-2 N). It contains 
 the elements of 2 at. cyanic acid, and 1 at. eugenic acid (2CNHO + C 10 H I2 2 ), and is 
 therefore analogous in composition to the allophanic ethers. 
 
 It is insoluble in water, sparingly soluble in cold alcohol, abundantly in hot alcohol. 
 
ALLOXAN. 135 
 
 It exhibits strong tendency to crystallise, so that even small quantities of the solution 
 yield needles of proportionally considerable length. It is very soluble in ether, is 
 destitute of taste and smell, has a silky lustre, and is permanent in the air. 
 
 Strong acids decompose it. Triturated with water and hydrate of barium, it forms 
 a stiff paste, consisting of eugenate and allophanate of barium. Alcoholic potash does 
 not appear to convert it into allophanate of potassium. When heated, it is resolved 
 into eugenic and cyanuric acids. (Baeyer, Ann. Ch. Pharm. cxiv. 164.) 
 
 See ISOMEEISM. 
 
 AX.X.OX.a.2?. (Alloxanhydridc, Laurent.) C 4 H 2 N 2 4 , or 
 History. Discovered in 1817 by Brugnatelli, who designated it Eryihrlc acid: 
 first completely investigated by Liebig and Wohler, in 1838 (Ann. Ch. Pharm. 
 xxvi. 256); more recently by Schlieper (Ann. Ch. Pharm. Iv. 253). 
 
 Formation and Preparation. Alloxan is one of the numerous products of the oxida- 
 tion of uric acid. Its preparation is a matter of some nicety. Liebig and Wohler 
 (loc. tit.) and Gregory (Phil. Mag. 1846), prepare it by the action of nitric acid on 
 uric acid: concentrated nitric acid specific gravity 1'4 to 1'42), must be employed, and 
 the temperature must not be allowed to rise above from 30 to 35 C. The process is 
 thus conducted. From 1| to 2 parts strong nitric acid are placed in a beaker or por- 
 celain basin, surrounded with cold water, and 1 pt. uric acid is added in successive 
 small portions, with constant stirring, care being taken not to add a fresh portion of 
 uric acid until the action caused by the addition of the former portion has quite sub- 
 sided. Carbonic anhydride and nitrogen are evolved with effervescence, the action 
 becoming gradually less violent as the operation proceeds ; and crystals of alloxan 
 gradually separate out. When the decomposition is complete, the mixture is left over 
 night in a cool place, and the crystalline magma is then thrown on a funnel plugged 
 with asbestos or coarsely pounded glass, and the last portions of the mother-liquor are 
 carefully removed by washing with ice-cold water, till the washings have only a faintly 
 acid reaction. Schlieper recommends removing the alloxan as it forms, in order to 
 withdraw it from the further action of the nitric acid. The crystals of alloxan are 
 dried by standing on filtering-paper or a porous tile, and then purified by solution in 
 the smallest possible quantity of water at from 60 to 80 C. ; the solution is filtered, 
 and cooled till it crystallises : by evaporating the mother-liquor at a heat not exceed- 
 ing 50 C. further crystals are obtained. The mother-liquor from these crystals, as 
 well as that originally drained off, still contains alloxan, which is best separated by 
 being previously converted into alloxantin. For this purpose, Schlieper proceeds as 
 follows : The mixed mother-liquors are nearly neutralised by carbonate of calcium or 
 sodium if the neutralisation were complete, the alloxan would be converted into 
 alloxanic acid and of the mixture are saturated with sulphuretted hydrogen, 
 whereby sulphur and alloxantin are precipitated, some dialuric acid being also formed 
 by the further action of the gas. The remaining | is then added, the alloxan in which 
 reconverts the dialuric acid formed into alloxantin. The alloxantin, which separates 
 out completely in 24 hours, is freed from sulphur by solution in boiling water and crys- 
 tallisation. In order to convert it into alloxan, one half of it is boiled with twice its 
 volume of water, nitric acid being added drop by drop until the evolution of nitric 
 oxide is perceptible, and the whole is heated in a water-bath until effervescence has 
 ceased : small portions of the remaining half are then added successively, until a fresh 
 addition produces no effervescence, then a little nitric acid, and so on till the nitric 
 acid is completely decomposed, a little alloxantin remaining in excess. The solution 
 is then filtered hot, and 3 or 4 drops of nitric acid added to the filtrate, which deposits 
 crystals of alloxan on cooling. The total weight of alloxan thus obtained, should be 
 about equal to that of uric acid employed. It is not advisable to operate on more than 
 70 to 80 grm. nitric acid at once. 
 
 Schlieper prefers chlorate of potassium to nitric acid as an oxidising agent. Into a 
 basin containing 124 grm. or 4 oz. of uric acid, and 240 grm. or 8 oz. of moderately 
 strong hydrochloric acid, he adds in successive portions, with constant stirring, 31 
 grm. or 6 dr. pulverised chlorate. Heat is evolved, which must not be allowed to 
 rise above a certain limit ; and a solution is obtained, containing only alloxan and 
 urea (C 5 H 4 N 4 3 + IPO + = C 4 H 2 N 2 4 + CH 4 N 2 0). If proper care be taken, no 
 gas is evolved. The solution is diluted with twice its volume of cold water, and de- 
 canted after three hours from any undissolved uric acid, which is heated to 50 with 
 a little strong hydrochloric acid, and oxidised by a fresh portion of chlorate. In order 
 to separate the alloxan from the urea, it is converted into alloxantin and reconverted 
 into alloxan in the manner above described. 
 
 The alloxan prepared by the above methods contains 1 or 4 atoms of water of crys- 
 tallisation. Anhydrous alloxan is obtained by heating the monohydrated compound 
 
 K 4 
 
136 
 
 ALLOXAN. 
 
 to 1/50 160 C. in a stream of dry hydrogen : the tetrahydrated compound must be 
 first converted into the monohydrate by very careful heating to 100. (Grmelin.) 
 
 Properties. Anhydrous alloxan is of a pale reddish colour, which is probably due 
 to the action of heat. When crystallised, it contains 1 or 4 atoms of water of crys- 
 tallisation. The crystals obtained by evaporating a warm aqueous solution, contain 
 1 atom of water : they are oblique rhombic prisms, belonging to the monoclinic system, 
 having the appearance of rhomboidal octahedra truncated at the extremities ; they 
 arc large, transparent, and colourless, of a glassy lustre, and do not effloresce in the 
 air. Liebig and Wohler regarded this compound as anhydrous. Those obtained by 
 cooling a warm saturated aqueous solution are transparent, pearly crystals, often an 
 inch long, belonging to the trimetric system : they effloresce rapidly in warm air, 
 and when heated to 100 are converted in the monohydrated compound. According 
 to Gregory, there exists a third hydrate containing 2| atoms of water. 
 
 Alloxan is readily soluble in water or alcohol, forming colourless solutions, whence 
 it may be precipitated by nitric acid. Its aqueous solution has an astringent taste, 
 and colours the skin purple after a time, imparting a peculiar and disagreeable smell. 
 It reddens litmus, but does not decompose alkaline-earthy carbonates : neither does it 
 attack oxide of lead, even on boiling. 
 
 The following is the percentage composition of the three varieties : 
 C 4 . . . 48 33-8 
 
 H a . 2 1-41 
 
 N*. . . 28 19-72 
 
 O 4 ., . _63 45-07 
 
 C 4 H 2 N 2 4 . 142 100-00 
 
 C'JBPN'O* 
 H 2 
 
 C 4 H 2 N 2 4 + aq. 
 
 C 4 H Z N 2 4 + H 2 
 
 3H 2 
 
 C 4 H 2 N 3 4 + 4 aq. 
 
 142 
 
 18 
 
 160 
 
 160 
 
 54 
 
 '214 
 
 Calc. 
 88-75 
 11-25 
 
 100-00 
 
 Calc. 
 
 74-77 
 25-23 
 
 100-00 
 
 L. a. W. 
 
 73-5 
 
 26-5 
 
 100-0 
 
 Gm. 
 
 88-65 
 11-35 
 
 "100-00 
 
 Gm. 
 
 74-72 
 25-28 
 
 100-00 
 
 Decompositions. 1. By Heat. When heated, alloxan melts, and is decomposed, 
 forming, besides other products, cyanide of ammonium and urea. (Handwb. d. Chim.) 
 
 2. By Electrolysis. An aqueous solution of alloxan is decomposed by the voltaic 
 current, oxygen being evolved at the positive pole, and crystals of alloxantin formed 
 at the negative pole. 
 
 3. By Nitric acid. Hot dilute nitric acid converts alloxan into parabanic acid and 
 carbonic anhydride : 
 
 C 4 IPN 2 4 + = C 3 H 2 N 2 3 + CO 2 
 
 Parabanic ac. 
 
 Further action of nitric acid converts the parabanic acid into nitrate of urea and car- 
 bonic anhydride. Monohydrated alloxan is scarcely attacked by heating with strong 
 nitric acid. (S c h 1 i e p e r. ) 
 
 4. By Hydrochloric and Sulphuric acids. When heated with these acids, alloxan is 
 converted into alloxantin, which gradually separates, and the mother-liquor yields on 
 evaporation acid oxalate of ammonium. The decomposition goes through several 
 stages : first, alloxantin, oxalic and oxaluric acids are formed ; then the oxaluric acid is 
 decomposed into oxalic acid and urea ; and the urea is finally resolved into carbonic an- 
 hydride and ammonia, which last combines with the oxalic acid. (Lie big and Wohler.) 
 
 5. An aqueous solution of alloxan is decomposed by boiling into carbonic anhydride, 
 parabanic acid, and alloxantin, which separating on cooling : 
 
 3C 4 H 2 N 2 4 = CO 2 + C 3 H 2 N 2 3 + C 8 H 4 N 4 7 
 
 * 1 Alloxantin. 
 
 Parabanic 
 acid. 
 
 6. By reducing agents, alloxan is converted into alloxantin. This decomposition is 
 effected by protochloride of tin, sulphuretted hydrogen, or zinc and hydrochloric acid 
 (nascent hydrogen) : 
 
 2C 4 H 2 N 2 4 + H 2 = C 8 H 4 N 4 7 + H 2 
 
 the further action of the two latter reagents converts the alloxantin into dialuric acid : 
 C 8 H 4 N<0 7 + IP + H 2 = 2C 4 H 4 N 2 0* 
 
 Dialuric acid. 
 
ALLOXANIC ACID. 137 
 
 The same decomposition is effected when an aqueous solution of alloxan is boiled with 
 excess of sulphurous acid. When, however, aqueous alloxan is saturated with sul- 
 phurous anhydride, and the solution evaporated at a gentle heat, it yields on cooling 
 large efflorescent tables of a conjugated acid, which, by analysis of its potassium-salt, 
 appears to contain the elements of 1 atom alloxan and 1 atom sulphurous anhydride 
 (Gregory). When a cold saturated solution of aqueous alloxan is treated with sul- 
 phurous acid in excess, ammonia added, and the whole boiled, thionurate of ammonium 
 is formed : 
 
 C 4 H=N 2 0* + NH 3 + S0 3 H 2 = C 4 H 5 N 3 SO + H 2 
 
 Thiontiric 
 acid. 
 
 7. By faced alkalis and alkaline earths, alloxan is converted into alloxanic acid : 
 
 C 4 H 2 N -2 4 + H 2 = C 4 H 4 N 2 5 
 Alloxanic 
 acid. 
 
 Aqueous alloxan gives with baryta- or lime-water a gradual white precipitate of allox- 
 anate of barium or calcium : a similar action is produced by a mixture of chloride of 
 barium, or nitrate of silver, with ammonia. If the alkali be in excess, the precipitated 
 alloxanate contains mesoxalate, and the nitrate contains urea (Schlieper). By boil- 
 ing with aqueous alkalis, alloxan is decomposed into mesoxalic acid and urea : 
 C 4 H 2 N 2 4 + 2 H 2 = C 3 H 2 5 + CH 4 N 2 
 
 Mesoxalic Urea, 
 
 acid. 
 
 8. "By Ammonia. A solution of alloxan in aqueous ammonia tnrns yellow when 
 gently heated, and on cooling forms a yellow transparent jelly of mycomelate of am- 
 monium : the liquid retains in solution alloxanate and mesoxalate of ammonium and 
 urea (Liebig) : 
 
 C 4 H 2 N 2 4 + 2NH 3 = C 4 H 4 N 4 2 + 2H 2 
 
 Mycomelic 
 acid. 
 
 9. With ferrous salts, aqueous alloxan gives a deep blue colour, but no precipitate 
 unless an alkali be added. 
 
 10. When aqueous alloxan is heated with peroxide of lead, carbonic anhydride is 
 evolved, carbonate of lead precipitated, and urea is contained in the solution : 
 
 C 4 H 2 N 2 4 + 4PbO + H 2 = CH 4 N 2 + 2C0 3 Pb 2 + CO 2 . 
 
 11. When aqueous alloxan is gradually added to a boiling solution of neutral acetate 
 of lead, mesoxalate of lead is precipitated, and urea remains in solution. When the 
 lead-solution is added to the alloxan-solution, alloxantin and oxalic acid are formed. 
 
 F. T. C. 
 
 AX.X.OXAIO-XC ACID. C 4 H 4 N 2 5 . = alloxan + H 2 0. 
 
 History. Discovered byLiebig and Wohler, in 1838 (Ann. Ch. Pharm. xxvi. 292), 
 further examined by Schlieper. (Ann. Ch. Pharm. Iv. 263, Ivi. 1.) 
 
 Formation and Preparation. Alloxanic acid is formed when alloxan is brought 
 into contact with aqueous fixed alkalis (see AXLOXAN), alkaline carbonates, or acid 
 carbonate of calcium (S t a d e 1 e r). It is prepared by decomposing alloxan ate of barium 
 by sulphuric acid. The salt is suspended in a little water, and a slight excess of dilute 
 sulphuric acid added, with constant agitation: 5 pts. salt require 1| pt. strong sul- 
 phuric acid, duly diluted. After digestion for some time at a gentle heat, the excess 
 of sulphuric acid is removed by pure carbonate of lead, the excess of lead by sul- 
 phuretted hydrogen, and the excess of gas by heat : the solution is then filtered, and 
 evaporated to a syrup, either over sulphuric acid in vacuo, or at a temperature not 
 exceeding 40 C. 
 
 Properties. Thus prepared, alloxanic acid forms hard white needles, arranged in 
 radiated groups, or in warty masses : if it has been heated above 40 C. it crystallises 
 with difficulty, or not at all. The crystals are permanent in the air: have a sour taste, 
 but a sweetish aftertaste ; are readily soluble in water, less readily, viz. in 5 to 6 pts. 
 alcohol, still less in ether. The solution is acid to litmus, readily decomposes car- 
 bonates and acetates, and dissolves zinc, cadmium, &c., with evolution of hydrogen. 
 Its composition is : 
 
 C 4 . . . 48 30-0 
 
 H* . 4 ... 2-5 
 
 N 2 ... 28 ... 17-5 
 
 0* . . . _80 . . . 50-0 
 
 C 4 H 4 N'0 S 160 
 
133 ALLOXANIC ACID ALLOXANTIN. 
 
 It is a dibasic acid, forming acid as well as normal salts : the formula of normal 
 alloxanates is C 4 H 2 M 2 N 2 5 , of acid alloxanates, C 4 H 3 MN 2 5 . It also appears to form 
 basic salts with some heavy metals. Alloxanates are mostly obtained by the action 
 of aqueous alloxanic acid on metallic carbonates. The alkaline alloxanates are soluble 
 in water : the normal salts of other metals are generally more or less insoluble, the 
 acid salts readily soluble. They part with their water of crystallisation at temperatures 
 varying from 100 C. to 150 ; and require a stronger heat for their decomposition. 
 
 The alloxanates have been investigated principally by Schlieper (loc. cit.}. The 
 only one which requires special mention is the normal barium-salt, which is employed 
 for the preparation of alloxanic acid. It is obtained by mixing 2 vols. of a cold satu- 
 rated solution of alloxan with 3 vols. of a cold saturated solution of chloride of barium, 
 heating the mixture to 60 or 70, and adding gradually potash-solution, with constant 
 agitation. Each addition of potash produces a white curdy precipitate, which soon 
 redissolves: at last the precipitate remains permanent, and the liquid suddenly 
 becomes filled with alloxanate of barium, which falls down as a heavy crystalline 
 powder, and may be freed from chloride of potassium by washing with cold water. 
 If too much potash has been added, a persistent curdy precipitate forms, consisting of 
 basic alloxanate and mesoxalate of barium ; it must be redissolved by the addition of 
 a little alloxan-solution. A less abundant, but more certainly pure product is obtained 
 by adding baryta-water to aqueous alloxanic acid. 
 
 Decompositions. 1. By Hea.t. When heated, the acid melts with intumescence, 
 becomes carbonised, and evolves vapours of cyanic acid. Alkaline alloxanates are 
 decomposed by heat into a mixture of carbonate and cyanide. An aqueous solution 
 of alloxanic acid is decomposed by boiling, carbonic anhydride being abundantly 
 evolved, and two new bodies formed, one of which, leucoturic acid, being insoluble in 
 water, separates as a white powder when the solution, after evaporation to a syrup, is 
 diluted with water; while the other, difluan, remains in solution, but may be preci- 
 pitated by alcohol. The latter is formed in far the larger quantity. The composition 
 of these bodies is not accurately established : Schlieper assigns to the former the for- 
 mula C 3 H 3 N ; 3 , to the latter, C 3 H 4 NW or C 6 H 4 N 2 5 . Schlieper states that a third 
 substance is also formed, soluble in water and alcohol, with the formula C 3 H 5 N 2 2 . 
 The alcoholic solution of alloxanic acid is not decomposed by boiling. Alloxanates are 
 decomposed by boiling with water into mesoxalate and urea : 
 
 C 4 H 4 N 2 5 + H 2 = c*H 8 5 + CH 4 N 2 
 
 2. When heated with nitric acid, alloxanic acid is decomposed into parabanic acid 
 and carbonic anhydride : 
 
 o = C 3 H'N 2 3 + CO 2 + H 2 0. 
 
 3. Alloxanate of potassium gives a dark blue precipitate with ferrous-salts. (See 
 ALLOXAN.) 
 
 Alloxanic acid is not decomposed by sulphuretted hydrogen, or by boiling with 
 bichromate of potassium or bichloride of platinum. 
 
 According to Ghnelin, the compound described byVauquelin (Mem. du. Mus. vii. 
 253) by the names acide purpurique blanc or urique suroxigenee (oxuric acid) is to be 
 regarded as impure alloxanic acid. F. T. C. 
 
 (Uroxin.} C 8 H 4 N 4 T +3H 2 [or C 16 H 4 N*0 1 \+6HO]. 
 
 History. Probably first noticed by P r o u t ; first described by L i e b i g and W 6 h 1 e r 
 in 1838 ; further examined by Fritz sche, who called it uroxin (J. pr. Chem. xiv. 237). 
 
 Formation and preparation. Alloxantin is formed in various reactions. 1. By 
 the action of warm dilute nitric acid on uric acid. 2. By the action of electrolysis, or 
 of reducing agents on alloxan, or by heating it with water or dilute sulphuric acid 
 (see ALLOXAN) : also by dissolving alloxan in dialuric acid. 3. By heating dialuramide 
 (uramil) with dilute sulphuric or hydrochloric acid, or thionurate of ammonium with 
 a large quantity of dilute sulphuric acid. 4. By the action of the air on dialuric acid. 
 6. In the decomposition of caffeine by chlorine. (Rochleder.) 
 
 The following are the most usual processes for the preparation of alloxantin. 
 1. Dry uric acid is added gradually to warm, very dilute, nitric acid, as long as it is 
 dissolved, and the solution evaporated till it has an onion-red colour; or dilute nitric 
 acid is added to 1 pt, uric acid in 32 pts. water, till all is dissolved, and the solution 
 evaporated to two-thirds ; the crystals obtained in either case are purified by re-crys- 
 tallisation from hot water. 2. Sulphuretted hydrogen is passed through an aqueous 
 solution of alloxan. till a crystalline magma forms ; this is dissolved by heat, the pre- 
 cipitated sulphur filtered off hot, and the filtrate crystallised. 3. A solution of alloxan 
 in dilute sulphuric acid is heated for a few minutes, when it becomes turbid, and do- 
 posits crystals of alloxantin on cooling. 4. Dialurate of ammonium is evaporated at 
 
ALLOXANTIN. 139 
 
 a gentle heat with a large excess of dilute sulphuric acid ; when dialuric acid crystal- 
 lises out, which is converted into alloxantin by the action of the air, without changing 
 its crystalline form. (Gregory.) 
 
 Properties. The alloxantin obtained by the above methods, contains 3 atoms of 
 water of crystallisation, which it does not lose till heated to above 150C. Of the 
 properties of anhydrous alloxantin nothing is known. The crystals are small, trans- 
 parent, colourless, or yellowish, oblique rhombic prisms, hard, but very friable. In 
 those prepared by methods 1, 2, and 3, the angle of the obtuse lateral edge is 105 : 
 in the dimorphous crystals obtained from dialurate of ammonium, it is 121. They 
 redden litmus, but do not exhibit acid properties in other respects. They are very 
 slightly soluble in cold water, more abundantly, but still slowly, in boiling water, 
 from which solution the alloxantin separates almost completely on cooling. The fol- 
 lowing is the percentage composition of anhydrous and hydrated alloxantin. 
 
 Anhydrous. Calc. Crystals. Calc. L. and W. Fritz sche. 
 
 C 8 96 35-8 C 8 96 29-81 30-52 30'06 
 
 H 4 4 1-5 H 10 40 3-11 3-15 3'04 
 
 N 4 56 20-9 N 4 56 17'39 17'66 17'52 
 
 O 7 112 41-8 O 10 160 48-67 48-67 49'38 
 
 T6(H) C 8 H 4 N<0 7 +3aq.322 100-00 ICMHM) lOO'OO 
 
 s. 1. By heat, alloxantin yields a peculiar crystalline product. 
 
 2. By oxidising agents, alloxantin is converted into alloxan. This change takes 
 place slowly, when its aqueous solution is exposed to the air, much more rapidly when 
 it, is heated with chlorine- water ; or when it is diffused in boiling water and a small 
 quantity of nitric acid added. Selenious acid also converts the hot solution of allox- 
 antin into alloxan, with separation of selenium. 
 
 3. By reducing agents, e. g. sulphuretted hydrogen, a hot solution of alloxantin is 
 converted into dialuric acid : 
 
 C 8 H 4 N 4 7 + H 2 S + H 8 = 2C 4 H 4 N 2 4 + S. 
 
 Dialuric acid. 
 
 4. When boiled with excess of hydrochloric acid, it is partly decomposed, and de- 
 posits on cooling, a white powder of allituric acid, C 3 H 3 N'-0 2 (Schlieper). At the 
 same time, alloxan and parabanic acid are formed, together with an acid which 
 Schlieper calls dilituric acid, which he has not succeeded in isolating. 
 
 5. With baryta-water, alloxantin gives a violet precipitate, which, on boiling, turns 
 white, and then disappears ; the solution contains alloxanate and dialurate of barium, 
 
 C s H 4 N 4 7 + 3BaHO = C 4 H 2 Ba 2 N 2 5 + C 4 H 3 BaN 2 4 + H 2 0. 
 Alloxanate Dialurate Ba. 
 
 Ba. 
 
 6. By ammonia, alloxantin is converted into purpurate of ammonium (murexide). 
 
 CH 4 N 4 7 + 2NH S = C 8 H 8 N 6 6 + IPO 
 
 Murexide. 
 
 This change takes place either in the wet or the dry way. In the dry way it occurs 
 when alloxantin is heated to 100 C. in an atmosphere of dry ammonia (Gmelin) : or 
 when it is exposed at the ordinary temperature to air containing ammonia. In the 
 wet way, an aqueous solution of alloxantin is coloured purple-red by ammonia : the 
 colour disappears on further heating, or when left for some time in the cold. When 
 nitric acid is gradually added to the hot alloxantin-solution, so as to form alloxan, 
 the addition of ammonia produces a deeper purple colour as the quantity of nitric 
 acid, and consequently of alloxan, increases ; but the coloration ceases when the 
 alloxantin is entirely converted into alloxan. When a solution of alloxantin in tho- 
 roughly boiled water is mixed with ammonia, and boiled till the purple colour has 
 disappeared, crystals of dialuramide (uramil) are deposited : the yellow mother-liquor 
 becomes purple by exposure to the air, deposits crystals of purpurate of ammonium, 
 and finally coagulates into a jelly of inycomelate of ammonium : 
 
 C 8 H 4 N 4 7 + 4NH 3 = C 4 H 5 N 3 3 + C'H 7 N 5 2 + 2H 2 0. 
 
 Uramil. Mycomel. 
 
 amm. 
 
 The formation of murexide depends upon the oxidation by the air of some of the 
 uramil which is dissolved in the ammonia. When a solution of alloxantin in aqueous 
 ammonia is repeatedly evaporated at a gentle heat in an open vessel, the residue being 
 each time dissolved in ammonia, pure oxalurate of ammonium is finally obtained : if the 
 air be excluded, this substance does not form. 
 
 7. Aqueous solutions of alloxantin and sal-ammoniac, both freed from air by boiling, 
 
1 40 ALLOXANTIN ALL YL. 
 
 form a purple-red mixture, which soon becomes paler, and deposits colourless or 
 reddish scales of uramil : the mother-liquor contains alloxan and hydrochloric acid : 
 
 C 8 H 4 N 4 7 + NH 4 C1 = C 4 H 5 N 3 S + C 4 H 2 N 2 4 + HC1. 
 
 Uramil. 
 
 Acetate or oxalate of ammonium acts like the chloride. 
 
 8. "When aqueous alloxantin is heated with oxide of silver, carbonic anhydride is 
 evolved, silver reduced, and oxalurate of silver formed : 
 
 C 8 H 4 N 4 7 + 4Ag 2 + H 2 = 2C 3 H 3 AgN 2 4 + 2C0 2 + 6Ag. 
 Oxalurate silver. 
 
 From nitrate of silver, alloxantin precipitates metallic silver: the filtrate gives a 
 white precipitate with baryta-water. Aqueous alloxantin dissolves mercuric oxide 
 with evolution of gas, probablv forming mercurous alloxanate. By peroxide of lead 
 alloxantin is converted like alloxan. 9. Aqueous alloxantin is decomposed by long 
 keeping, even out of contact with air, and is converted into alloxanic acid. (Gregory.) 
 
 Te tram ethyl -Alloxantin, C 8 H 14 N 4 8 = C 4 (CH 3 ) 4 N 4 7 + H 2 0. This composi- 
 tion is assigned by Gerliardt to a product of the action of chlorine on caffeine, disco- 
 vered byKochleder (Ann. Ch. Pharm. Ixxi. 1), also called Amalic acid (q. v.) F.T. C. 
 
 AX.X.OYS. (See METALS.) 
 
 ALLtTAUDITE. (See TuTPHYLINE.) 
 
 AX.X.YX.. Acryl, Propylenyl. C 3 H 5 . Berthelot and De Luca in 1854 (Ann. 
 Ch. Phys. [3] xliii. 257), by acting on glycerin with iodine and phosphorus, obtained 
 the compound C 3 H 5 I, which they regarded as iodotritylene, that is to say, tritylene, C 3 H fi , 
 having 1 at. H replaced by iodine, but which is now rather regarded as the iodide 
 of the radicle allyl. Ziniu, in 1855 (Ann. Ch. Pharm. xcv. 128) by acting on this 
 iodide with sulphocyanate of potassium, obtained a volatile oil, the sulphocyanate of 
 allyl, C 3 H 5 .CyS, identical with volatile oil of mustard, and afterwards (Ann. Ch. 
 Pharm. xcvi. 361) prepared the benzoate, acetate, &c. of the same series. Hofmann 
 andCahours, in 1856 (Compt. rend. xlii. 217 ; more fully, Phil. Trans. 1857, 1; 
 Ann. Ch. Pharm. cii. 285; Chem. Soc. Qu. J. x. 316), discovered allylic alcohol and 
 prepared a great number of its derivatives. Lastly, Berthelot and De Luca in the 
 same year isolated the radical allyl, and prepared the dibromide and diniodide. The 
 existence of this radicle in the oils of mustard and garlic was first demonstrated 
 by Wertheim. (Ann. Ch. Pharm. li. 289; Iv. 297.) 
 
 Allyl is the third term in the series of homologous radicles C"!! 11 - 1 , vinyl C 2 H 3 
 being the second; it is the only radicle of the series that has yet been isolated. 
 
 Allyl, in the free state, C 6 H' = C 3 H 5 .C 3 H 5 , is obtained by decomposing the iodide, 
 C s iPI, with sodium at a gentle heat, and afterwards distilling the liquid product. It 
 is a very volatile liquid having a peculiar pungent, ethereal odour, somewhat like that 
 of horse-radish. Specific gravity 0-684 at 14. Boils at 59 C. Vapour-density by ex- 
 periment 2-92 , by calculation from the formula C y H 10 (2 vol.) 2'89. Allyl is but 
 little attacked by strong sulphuric acid. Fuming nitric acid changes it into a neutral 
 liquid nitro-compound, soluble in ether and decomposed by heat. Chlorine acts 
 strongly upon it, hydrochloric acid being evolved and a liquid compound formed 
 heavier than water. Bromine and iodine unite directly with it, forming the com- 
 pounds C 3 H 5 Br 2 and C 3 H 5 I 2 . (Berthelot and De Luca.) 
 
 AX.X.-KX-AX.COHOX.. Hydrate of Allyl, C 3 H 6 = G ^ J 0. Prepared by the 
 action of ammonia on oxalate of allyl, oxamide being formed at the same time : 
 (C 2 2 )"(C 3 H 5 ) 2 O a + 2NH 3 = 2(C 3 H 5 .H.O) + N 2 .(C 2 2 )" .H 4 . 
 
 Oxalate of allyl. Allyl-alcobol. Oxamide. 
 
 Dry gaseous ammonia is passed into oxalate of allyl till the whole is converted into a 
 solid mass of oxamide saturated with allyl-alcohol. The latter is then distilled off in 
 a bath of cliloride of calcium, and rectified over anhydrous sulphate of copper. The 
 alcohol appears also to be produced by distilling benzoate or acetate of allyl with 
 potash (Zinin, Ann. Ch. Pharm. xcvi. 362). It is a colourless liquid, having a 
 pungent but not unpleasant odour, and a spirituous burning taste. It mixes in all pro- 
 portions with water, common alcohol, and ether. It burns with a brighter flame than 
 common alcohol. Boiling-point 103 C.* It gave by analysis, 62*08 per cent. C and 
 10-43 H, the formula C 3 H 6 requiring 62-07 C, 10'34 H, and 27'5 9 0. 
 
 * One sample of the alcohol very carefully prepared, Wris found to boil between 00 and 100 C. Thig, 
 h< \vi-ver, may h;ive arisen Irom decomposition ; at all events, the number 10H agrees with the differ- 
 ences generally ob>erved in analogous ethyl and allyl-compuunds. (Hofmann.) 
 
ALLYL, BROMIDES OF. 141 
 
 Allyl-alcohol is strongly attacked by phosphoric anhydride, a colourless gas, pro- 
 bably C 3 H 4 , being given off, which burns with a very bright flame. It is violently 
 oxidised by a mixture of acid chromate of potassium and sulphuric acid, with forma- 
 tion of allylic aldehyde (acrolein), C 3 H'0, and acrylic acid, C 3 H 4 O 2 . The same trans- 
 formation is effected, though more slowly, by platinum black. Potassium (or sodium) 
 decomposes allyl-alcohol, with evolution of hydrogen and formation of a gelatinous 
 mass of allylate of potassium, C 3 H 4 KO. Strong sulphuric acid acts on it in the same 
 manner as on common alcohol, converting it into allyl-sulphuric acid, C'HAH.SO 4 . 
 With potash and disulphide of carbon, it yields the potassium-salt of allyl-xanthic 
 acid, C 4 H 6 S 2 0. 
 
 
 BROIVKIDES OP. The monobromide, C 3 H 5 Br, which is isomeric, 
 or perhaps identical with bromotritylene, is obtained by the action of bromide of phos- 
 phorus on allyl-alcohol (Hofmann and Cahours); or by distilling dibromide of 
 tritylene, C 3 H ti Br 2 (or hydrobromate of bromotritylene, C 3 H 5 Br.HBr) with alcoholic 
 potash (Cahours). Its specific gravity is 1-47, and boiling-point 62 C. (Cahours.) 
 
 The hydrobromate of this compound, or dibromide of tritylene, is produced when 
 bromine is gradually passed into an excess of tritylene gas ; but when tritylene is 
 passed into excess of bromine, a number of compounds are formed which may be re- 
 garded as compounds of hydrobromic acid with bromide of allyl having its hydrogen 
 more or less replaced by bromine. (See TBITTLENE.) 
 
 Dibromide of Allyl, C 3 H 6 Br 2 . Allyl unites directly with bromine, the com- 
 bination being attended with evolution of heat. If the action be stopped just as the 
 liquid begins to show colour from excess of bromine, and to give off hydrobromic acid, 
 and if the liquid be then treated with potash, dibromide of allyl is obtained as a 
 crystalline body, very soluble in ether. It melts at 37 C. and when once fused, 
 sometimes remains liquid at ordinary temperatures. It may be volatilised without 
 decomposition (Berthelot and De Luca). The allyl in this compound takes the 
 place of 2 at. H. 
 
 Tribromide of Allyl, C s H 5 Br 3 . Obtained by gradually adding bromine to 
 iodide of allyl in a vessel surrounded by a freezing mixture. The mixture is left to 
 itself till the next day ; freed from crystallised iodine by washing first with alkaline and 
 afterwards with pure water ; then dried and distilled ; the liquid which passes over is 
 again washed and distilled, collecting apart that which goes over from 210 to 220 C.; 
 the purple liquid then obtained is cooled to C. whereupon it solidifies in a crys- 
 talline mass ; the mother-liquor is drained off; and the product is fused and again 
 rectified. By this method, tribromide of allyl is obtained as a colourless neutral 
 liquid, of not unpleasant odour, specific gravity 2*436 at 23 C., boiling at 217 
 or 218, and solidifying below 10. By slow solidification, it yields shining prisms, 
 which melt at 16. (Wurtz, Ann. Ch. Phys. [3] Ix. 84.) 
 
 Alcoholic potash converts it into an ethereal substance boiling at 135 C. Heated to 
 100 in a sealed tube with alcoholic ammonia, it is converted into Dibromallylamine, 
 N.H.(C 3 H'Br) 2 (M. Simpson, Phil. Mag. [4] xvi. 257). The decomposition appears 
 to consist of two stages ; in the first, the compound C 8 H 5 Br 3 , is converted into C 3 H 4 Br 2 , 
 and in the second, this latter is converted into dibromallylamine : 
 
 C 3 H 5 Br 3 -t- NH 3 - C 3 H 4 Br 2 + NH 4 Br. 
 
 (C 3 H 4 Br 
 
 and 2C 3 H 4 Br 2 + 3NH 3 = N^C 3 H 4 Br + 2NH 4 Br. 
 ( H 
 
 Dissolved in glacial acetic acid, and heated with acetate of silver to 120 125 C. 
 for a week, it yields bromide of silver and triacetin (p. 25.) 
 
 + 3AgB, 
 
 The radicle C 3 H 5 in this compound is triatomic, replacing 3 at. hydrogen, as seen in 
 the reaction just mentioned ; in other words the compound is formed on the type H 3 .H 3 . 
 Wurtz has obtained two compounds (or perhaps only one) isomeric with it, by the ac- 
 tion of bromine on bromotritylene, C 3 H 5 Br. and on the isomeric body bromide of allyl. 
 These compounds are perhaps formed on the type H 2 .H 2 , their rational formula being 
 C 3 H 4 Br.Br*. They both have a specific gravity of 2'392 at 23 C., and boil at about 
 195 ; but they differ somewhat in odour and in their action on silver-salts, the 
 former being more energetic in both respects than the latter (Wurtz). The action 
 of bromide of bromallyl on ammonia is totally different from that of tribromide of 
 allyl, giving rise, not to dibromallylamine, but to the compound C 3 H 4 Br 2 .C 3 IPBi :S . 
 ^Simpson.) 
 
142 ALLYL-COMPOUNDS. 
 
 HXiORIDE OP. Chlorotritylene, C 3 H 5 C1, is obtained like the bro- 
 
 mide, by the action of chloride of phosphorus on allyl-alcohol, or by treating chloride 
 of tritylene, C 3 H 6 .CF (hydrochlorate of allyl-chloride, C 3 H 5 C1.IIC1) with alcoholic 
 potash. The last mentioned compound treated with excess of chlorine yields substi- 
 tution-products similar to those obtained with the bromide. (See TKITYUENE.) 
 
 AZ.Z.YX. HYDRIDE OP, C 3 H 6 = C 3 H 5 .H. Tritylene or propylene, the third 
 term in the series of hydrocarbons C"H 2n , is perhaps the hydride of allyl. 
 
 AXiXTSTXi, IODIDES OP. The monoiodide (iodotritylene) C 3 H 5 I, is obtained 
 by distilling glycerin at a gentle heat with diniodide of phosphorus ; 
 
 2C 3 H 8 S + 2PI 2 = 2C 3 H 5 I + P 2 3 + 3H-0 + 21. 
 
 A quantity of tritylene-gas is given off, due to a secondary action, and a mixture of 
 oxygen-acids of phosphorus with iodine and undecomposed glycerin remains in the 
 retort. Tri-iodide of phosphorus may also be used, but the action is less regular. 
 The distillate is purified by rectification, the portion which passes over at 100 C. 
 being collected apart (Bert helot and De Luc a). Iodide of allyl is also produced by 
 the action of iodine and phosphorus on allyl-alcohol. (Hofmann and Oahours.) 
 
 "When first prepared, it is colourless, and has an ethereal alliaceous odoxir ; but by 
 the action of air and light, it becomes coloured and then gives off irritating vapours 
 Specific gravity 1'789 at 160 C. Boiling-point 101. It is insoluble, in water, but 
 dissolves in alcohol and ether. By the action of zinc or mercury, and hydrochloric 
 or dilute sulphuric acid, it is converted into tritylene (hydride of allyl) : 
 
 C 3 H 5 I + 4Hg + HC1 = C 3 H 8 + Hg 2 Cl + Hg 2 I. 
 and C 3 IPI + 2Zn + HC1 = C 3 H e + ZnCl + Znl. 
 
 Iodide of allyl is decomposed by silver-salts, iodide of silver being formed, and the 
 acid radicle being transferred to the allyl. 
 
 Diniodide of Allyl, C 3 H 5 I 2 . Obtained by dissolving 6 or 7 pts. of iodine in 
 1 pt. of allyl at a gentle heat. The mixture, which is liquid at first, solidifies after a few 
 minutes ; and by triturating the mass with aqueous potash, then digesting in boiling 
 ether, and evaporating the ethereal solution, the diniodide of allyl is obtained in the 
 crystalline form. It is decomposed by distillation, yielding iodine and a neutral 
 liquid. It is scarcely attacked by aqueous potash ; but alcoholic potash decomposes 
 it, producing a liquid which smells like allyl. It is not acted upon by mercury and 
 hydrochloric acid. (Berthelot and De Luc a.) 
 
 Iodide of Mercurallyl, C H 5 Hg 2 I, is obtained by agitating iodide of allyl with 
 metallic mercury. On crystallising the resulting yellow mass from a boiling mixture 
 of alcohol and ether, nacreous scales are formed, which turn yellow when exposed to 
 light, especially if moist. They dissolve but sparingly in cold alcohol, and are nearly 
 insoluble in boiling alcohol. Heated to 100 C. they sublime in rhombic plates; at 
 135 they melt, and solidify in a crystalline mass on cooling. When quickly heated, 
 they decompose, yielding a yellow sublimate and a carbonaceous residue. The alco- 
 holic solution treated with oxide of silver, yields a strongly alkaline liquid, which 
 when evaporated leaves a syrupy mass, probably consisting of hydrate of rnercurallyl. 
 (Zinin.) 
 
 AX.X.YX., OXIDE OP. AUylic ether, (C 3 H 5 ) 2 0, is produced by the action of iodide 
 of allyl on ally late of potassium : 
 
 C 3 H 5 KO + C 3 H S I = KI + (C 3 H 5 ) 2 0; 
 
 also by the action of oxide of silver or oxide of mercury on iodide of allyl : 
 2C 3 H 5 I + Ag 2 = 2AgI + (C 3 H 5 ) 2 0. 
 
 A body having the same composition was obtained by Wertheim (Ann. Ch. Pharm. 
 li. 309 ; Iv. 297), by acting on oil of garlic, (C 3 H 5 ) 2 S, with nitrate of silver, and dis- 
 tilling the crystalline product thereby produced; also by heating oil of mustard 
 (sulphocyanate of allyl), with fixed alkalis, e. g. with soda-lime. 
 
 Oxide of allyl is a colourless liquid, lighter than water, and insoluble in water. 
 It boils at 82 C. (Hofmann and Cahours) ; between 85 and 87 C. (Berthe- 
 lot and De Luc a). It forms with sulphuric acid a conjugated acid yielding a 
 soluble barium-salt. Nitric acid converts it into a nitro-compound heavier than 
 water. "With iodide of phosphorus, it yields iodide of ally]. Heated with butyric 
 acid it is decomposed, with formation of butyrate of allyl. (B. and L.) 
 
 Ethyl-allyl-ether, C 5 H 10 = C-H 5 .C 3 H 5 .0, is obtained by the action of iodide of 
 ethyl on allylate of potassium, or of iodide of allyl on ethylate of potassium. It is a 
 colourless aromatic, very volatile liquid, boiling at about 84 C. Similar compounds 
 
ALLYL, SULPHIDE OF. 143 
 
 are produced by treating iodide of allyl with methylate, amylate, and phenylate of 
 potassium (Hofmann and Cahours). Amyl-allyl-ether boils at about 120 C. 
 (Berthollet and De Luca.) 
 
 Oxide of Allyl and Glyceryl, or Triallylin, C 12 H 20 3 = [cH*)'| 3 - Iodide 
 of aUyl distilled with potash and glycerin yields this compound in the form of a liquid, 
 boiling at 232 C., soluble in ether, and having a disagreeable odour. (Bert he lot 
 and De Luca): 
 
 (C 3 H 5 )"'.H 3 .0 3 + 3C 3 H 5 I = SHI + (C 3 H 5 )"'.(C 8 H 5 ) 3 3 . 
 
 The formula is that of a triple molecule of water H 6 3 , in which 3 at. H are replaced 
 by the triatomic radicle glyceryl, and the other three by 3 at. of the monatomic 
 radicle allyl. 
 
 AXiXiYX., OXYGEK'-SAI.TS OP. Acetate, oxalate, sulphate, &c. (See the 
 several acids.) 
 
 AX.X.1T3J, SULPHIDE OF. Oil of garlic, C 8 H'S = (C 3 H 5 ) 2 S [or CH 5 S~\. This 
 compound is produced by distilling iodide of allyl with protosulphide of potassium : 
 
 2C 3 H 5 I + K 2 S = 2KI + (C 3 H 5 ) 2 S, 
 
 and is contained in the essential oils produced by distilling with water the leaves 
 and seeds of various plants of the liliaceous and cruciferous orders. It forms the 
 principal constituent of the oil obtained from the bulbs of garlic (Attium sativum), 
 from which it was first obtained in the pure state by Wertheim in 1844 ; and it 
 exists in smaller quantity in oil of onions (Allium cepa). It occurs also, together with 
 10 per cent, of oil of mustard (sulphocyanate of allyl), in the herb and seeds of 
 Thlaspi arvense, passing over when these matters are bruised with water and dis- 
 tilled. The leaves of Alliaria officinalis distilled with water yield oil of garlic ; the 
 seeds yield oil of mustard (Wertheim). The bruised seed distilled after maceration 
 in water, yields a mixture of 10 per cent, oil of garlic, and 90 oil of mustard ; but the 
 seed produced in sunny places yields only the latter. The herb and seeds of Thlaspi 
 arvense yield a mixture of 90 per cent, oil of garlic, and 10 oil of mustard. The herb 
 and seeds of Iberis amara likewise yield a mixture of the two oils ; and very small 
 quantities of the same mixture are obtained from the seeds of Capsella Bursa Pas- 
 toris, Eaphanus Raphanistrum, and Sisymbrium Nasturtium. (PI ess, Ann. Ch. 
 Pharm. Iviii 36.) 
 
 To obtain the whole of the mixed oils, the several parts of the plants, especially 
 the seeds, must be macerated in water some time before distillation. For, in the 
 seeds of Thlaspi arvense, for example, the oils do not exist ready formed ; the seeds, 
 in fact, emit no odour when bruised, and if before distillation with water, they are 
 heated to 100 C. or treated with alcohol, no oil passes over; and if the seed be ex- 
 hausted with alcohol, and the filtrate evaporated, there remains a crystalline residue 
 mixed with mucus, which, when triturated with water and with the seed of Sinapis 
 arvensis, yields, not oil of garlic, but oil of mustard. (PI ess, Ann. Ch. Pharm, 
 Iviii. 36.) 
 
 Preparation, a. From Iodide of Allyl. The iodide is cautiously dropped into a 
 concentrated alcoholic solution of sulphide of potassium, the liquid then becoming 
 very hot, and an abundant crystalline deposit of iodide of potassium being formed. 
 As soon as the action ceases, the liquid is mixed with a slight excess of sulphide of 
 potassium ; water is then added, and the oil which rises to the surface is rectified. 
 
 b. From Garlic. The crude oil is obtained by distilling bruised garlic-bulbs with 
 water in a large still. The oil passes over with the first portions of water, the pro- 
 duct amounting to 3 or 4 oz. from 100 pounds of the bulbs. The milky water which 
 passes over at the same time, contains a large quantity of oil in solution, and serves 
 therefore for cohobation. The crude oil is heavier than water, of dark brownish- 
 yellow colour, and has a most intense odour of garlic. It decomposes at 140 C. ; 
 that is to say, somewhat below its boiling-point, which is 150, becoming suddenly 
 heated, assuming a darker colour, and giving off intolerably stinking vapours, 
 without yielding a trace of garlic oil ; the residue is a black-brown glutinous mass 
 (Wertheim.) 
 
 Preparation of the rectified oil. The crude oil is distilled in a salt-bath (in the 
 water-bath the distillation is slower) as long as anything passes over. One-third of 
 the crude oil remains behind as a thick dark-brown residue. The rectified oil is 
 lighter than water, and of a pale yellow colour, or after two distillations, colourless, 
 and smells like the crude oil, though less offensive. Does not evolve a trace of 
 of ammonia when treated with hydrate of potash. It covers potassium with a liver- 
 coloured film of sulphide of potassium, depositing an organic substance, and giving 
 off a small quantity of a gas which burns with a pale blue flame. With fuming nitric 
 
144 ALLYL, SULPHIDE OF. 
 
 acid, oil of vitriol, hydrochloric acid gas, dilute acids and alkalis, corrosive sublimate, 
 nitrate of silver, bichloride of platinum and nitrate of palladium, it behaves like pure 
 sulphide of allyl. Even after being several times rectified and dried with chloride of 
 calcium, it exhibits a variable composition and a certain amount of oxygen, and 
 must therefore contain, besides sulphide of allyl, an oxygen compound, probably 
 oxide of allyl, the presence of which is indeed indicated by the reaction with potassium. 
 (Wertheim.) 
 
 Preparation of pure Oil of Garlic or Sulphide of Allyl. The rectified oil is again 
 rectified several times ; dehydrated over chloride of calcium ; decanted ; a few pieces 
 of potassium introduced into it ; and as soon as the evolution of gas thereby produced 
 has ceased, the oil is quickly distilled off from the residue. The rectified oil appears 
 to contain oxide as well as sulphide of allyl, together with excess of sulphur, these 
 impurities either pre-existing in the crude oil, or being formed from sulphide of allyl 
 by the action of atmospheric oxygen, that portion of the sulphide which takes up the 
 oxygen, giving up its sulphur to the rest. If the potassium be not suffered to 
 complete its action before the liquid is distilled, it merely removes the excess of 
 sulphur, but does not decompose the oxide of allyl, and a distillate is obtained, con- 
 taining from 65-17 to 6475 per cent. C, and 9'22 to 9-15 H. (Wertheim.) 
 
 Properties. Colourless oil, of great refracting power, and lighter than water. 
 Boils at 140 C. May be distilled without decomposition. Smells like the crude oil 
 but less disagreeably. It dissolves sparingly in water, readily in alcohol and ether. 
 
 Calculation. Wertheim. 
 
 60 . . 72 . . 63-16 . . 63-22 
 
 10H . . 10 . . 8-77 . . 8-86 
 
 S . . 32 . . 28-07 . . 27-23 
 
 (C 3 H 5 ) 2 S 114 100-00 99-31 
 
 Decompositions. 1. Sulphide of allyl dissolves with violent action in fuming nitric 
 acid ; the solution when diluted with water, deposits yellowish- white flakes, and is 
 found to contain oxalic and sulphuric acids; according to Hlasiwetz (J pr. Chem. 
 li. 355) oil of garlic treated with nitric acid, yields formic and oxalic acids. 2. With 
 cold oil of vitriol, it forms a purple solution, from which it is separated by water, 
 apparently without alteration. 3. It absorbs hydrochloric acid gas in large quan- 
 tities ; the deep indigo-coloured mixture becomes gradually decolorised on exposure 
 to the air, and immediately if gently heated or diluted with water. 4. From nitrate 
 of silver, it throws down a large quantity of sulphide of silver, whilst nitrate of silver 
 and allyl remains in solution (Wertheim). It is not altered by dilute acids or 
 alkalis, or by potassium. 
 
 Combinations. Sulphide of allyl does not precipitate the aqueous or alcoholic solu- 
 tions of acetate of nitrate of lead, or acetate of copper ; neither does it precipitate the 
 solution of arsenious or arsenic acid in aqueous sulphide of ammonium. 
 
 With solutions of gold, mercury, palladium, platinum, and silver, it forms precipi- 
 tates, consisting of a double sulphide of allyl and the metal, either alone or associated 
 with a double chloride. 
 
 Gold-precipitate. Sulphide of allyl forms with aqueous trichloride of gold, a beauti- 
 ful yellow precipitate, which resembles the platinum-precipitate, but soon cakes together 
 in resinous masses, and becomes covered with films of gold. 
 
 Mercury-precipitate. Alcoholic solutions of oil of garlic and corrosive sublimate 
 form a copious white precipitate, which when left to stand for some time, and espe- 
 cially if diluted with water, increases to a still greater quantity. It is a mixture of 
 the compounds a and b, which may be separated by continued boiling with strong 
 alcohol, only the compound a being soluble therein. (Wertheim.) 
 
 a. The alcoholic filtrate, when left to itself or evaporated with water, and after 
 washing and drying, yields a white powder, agreeing in composition with the formula 
 (C 3 H 5 )*S.2Hg 2 S + 2(C 3 H 5 C1.2HgCl), or 2(C 3 H 5 )'- : 8.Hg-S.6HgCl (anal. 10-91 C, 1-61 H, 
 63-67 Hg, and 16-41 Cl : calc. 11-32 C, 1'57 H, 62-87 Hg, and 1670 01). It blackens 
 superficially on exposure to the sun ; when heated, it gives off vapours smelling like 
 onions,and yields a sublimate of calomel and mercury. When immersed in moderately 
 strong potash-ley, it acquires a light yellow colour from separation of oxide of mercury; 
 if this oxide be then removed by dilute nitric acid, there remains a white substance, 
 probably = (C 3 H 5 ) 2 S.2Hg 2 S. When distilled with sulphocyanate ^of potassium, it 
 yields oil of mustard, together with other products. It is insoluble in water, and dis- 
 solves but sparingly in alcohol and ether. (Wertheim.) 
 
 b. The portion of the mercury-precipitate insoluble in hot alcohol contains the same 
 constituents, and has the carbon and hydrogen likewise in the ratio of 6 : 5 at., bufc is 
 much richer in mercury. (Wertheim.) 
 
ALLYL. 145 
 
 Palladium-precipitate. When rectified oil of garlic is gradually added to a solution 
 of nitrate of palladium, kept in excess, a brown precipitate is formed, which appears 
 to contain 2C s H 10 S.3Pd 2 S. Chloride of palladium forms with oil of garlic a yellow 
 precipitate, probably consisting of the preceding compound mixed with chloride of 
 palladium. 
 
 Platinum-precipitate. Oil of garlic forms a yellow precipitate with dichloride of 
 platinum. This precipitate is obtained of a finer yellow colour by the use of alcoholic 
 solutions ; but when strong alcohol is used, its formation is gradual, becoming instanta- 
 neous however on addition of water. If the water be added too quickly and in too great 
 quantity, the precipitate is yellowish-brown, resinous, and difficult to purify ; the addi- 
 tion of water must therefore be stopped as soon as a strong turbidity appears ; in that 
 case, if the oil of garlic is not in excess, a copious flocculent precipitate is sure to be ob- 
 tained, resembling chloro-platinate of ammonium. The precipitate is washed on the filter, 
 first with alcohol, then with water, and dried at 100 C. When heated considerably 
 above 100, it changes colour, and leaves sulphide of platinum in so porous a condition 
 that it takes fire at a higher temperature, and continues to glow till it is reduced to pure 
 platinum. Fuming nitric acid decomposes and dissolves the precipitate completely, 
 forming dichloride of platinum and platinic sulphate. When immersed in hydrosulphate 
 of ammonium, it is gradually converted into the kermes-brown compound next to be 
 described. Aqueous potash and sulphuretted hydrogen have no action upon it. The 
 precipitate is nearly insoluble in water, and dissolves but sparingly in alcohol and ether. 
 It gives by analysis 17*85 per cent. C, 2'87 H, 48'53 Pt, 18-29 S, and 13-22 CJ, 
 whence Wertheim deduces the somewhat improbable formula, 3(C e II IO S.2PtS) + 
 2(C 3 H 5 Cl.PtCl 2 ), which requires 1777 C, 2-47 H, 48-88 Pt, 1777 S, andl3;ll Cl. 
 
 Kermcs-brown compound, (C i H 5 ) 2 S.2PtS. Formed, together with dissolved sal- 
 ammoniac, when the platinum-precipitate just described is left in contact and shaken 
 up -with hydrosulphate of ammonium. The brown compound heated to 100 C. emits an 
 alliaceous odour, and gives off 4-88 per cent, of sulphide of allyl. The darker substance 
 containing excess of platinum which remains, continues unaltered till it is heated to 
 140 C. but between 150 and 160, gives off 5'17 per cent, more, therefore in all 9'55 
 per cent, of sulphide of allyl, leaving a still darker compound of (C 3 H 5 ) 2 S with 3PtS. 
 The kermes-brown compound is insoluble in water, alcohol, and ether. (Wertheim.) 
 
 Silver-precipitate. When a solution of nitrate of silver in aqueous ammonia is 
 mixed with excess of sulphide of allyl, .one portion of the compound resolves itself 
 into oxide of allyl, which rises to the surface as an oil, and nitrate of ammonium ; but 
 there is also formed at the beginning a white or pale yellow precipitate, which perhaps 
 consists of (C 3 H 5 ) 2 S + J?Ag'-'S. For if it be immediately washed with alcohol, and 
 dried between paper, it is resolved by distillation into sulphide of allyl and a residue 
 of sulphide of silver. But if it remains half an hour immersed in the liquid, it 
 assumes a continually darker brown colour, and is finally converted into black sulphide 
 of silver. (Wertheim.) 
 
 AX.Z.YX. and' HYDROGEN, SITX.PHXDE OP. Allyl-mercaptan, C 3 H fi S = 
 C 3 H 5 .H.S. Produced by distilling iodide of allyl with sulphide of hydrogen and 
 potassium : 
 
 C 3 H 5 I + KHS = KI + C 3 H 5 .H.S. 
 
 It is a volatile oily liquid, having an odour like that of oil of garlic, but more ethereal. 
 It boils at 90 C. It is powerfully attacked by nitric acid, assuming a red colour, and 
 yielding an acid analogous to ethyl-sulphurous acid. It acts with great energy on 
 mercuric oxide, forming a compound C 3 H 5 HgS, which dissolves in boiling alcohol, and 
 separates from the solution in pearly scales resembling mercaptide of mercury. (Hof- 
 mann and Cahours.) 
 
 AX.Z.YX,, SU1.PHOCYANATE OF. C 4 H 5 NS = CNS.C 3 IF. Volatile Oil of 
 Mustard. (See SULPHOCYANIC ETHERS.) 
 
 AX.X.YX.-SUX.PHGCARBAXVEXC,orSlTX.PHOSZarAPXC ACID. C'IFNS 2 = 
 ( "NT ( CSV C 3 H 5 H 
 S j Jj^ ' . This acid is not known in the separate state, but its soluble 
 
 Baits, viz. those containing the metals of the alkalis and alkaline earths, are obtained 
 by treating oil of mustard with the hydrosulphates of those metals : e. g. 
 
 C 4 H 5 NS + KHS ~ C<HKNS 2 . 
 
 It may bft regarded either as composed according to the preceding formula, that is to 
 say, as hydrosulphate of ammonium, NIP.H.S, having 1 at. H in the ammonium-mole- 
 cule replaced by allyl and two more by the diatomic radicle CS, or as a compound of 
 sulphocyanide of allyl with sulphide of hydrogen. The mode of formation leads 
 directly to the latter view. (See SuLmosiNAPic ACID.) 
 VOL. I. L 
 
146 ALLYL. 
 
 AXjI/Sr-SUXPHOCARBONXC, or AX.X.YX.-XANTHXC ACID 
 
 of Allyl, Carbonyl, and Hydrogen, C 4 H 6 S S = S 2 | H ^^. When 
 
 treated with potash and disulphide of carbon, a salt is formed, which crystallises in 
 yellow needles like xanthate of potassium. (Hofmann and Cahours.) 
 
 AX.X.YX.-SUX.PHURXC ACID. C 3 H 5 .H.S0 4 . Sulphate of Allyl and Hydrogen. 
 (See SULPHURIC ETHERS.) 
 
 AX.X.YI.-T7REA. (See CARBAMIDE.) 
 
 AX^XiYX.AXVXXXTX:. C'H'N = N.H' 2 .(C 3 H 5 ), is obtained by the action of ammonia 
 on iodide of allyl, or by boiling cyanate of allyl with strong aqueous potash. 
 
 CNO.C 3 H 5 + 2KHO = C0 8 K 2 + N.H 2 (C 3 H 5 ). 
 
 If the alkaline distillate be condensed in hydrochloric acid, a saline mass is obtained, 
 which when distilled with potash, yields, among other products, a basic oil having the 
 composition of allylamine. The platinum-salt, C 3 H 7 N.HCl.PtCl 2 , separated from 
 solution by slow evaporation forms magnificent crystals. 
 
 DIAIXYLAMINE, C 6 H 1J N = N.H.(C 3 H 5 ) 2 , is formed, together with other products, by 
 the action of iodide of allyl on allylamine. 
 
 DIBROMAIXYLAMINE, C 6 H 9 Br 2 N = N.H.(C 3 H 4 Br) 2 . Produced by the action of am 
 monia on tribromide of allyl (p. 141). 
 
 2C 3 H 5 Br 3 + 5NH 3 = C fi H 9 Br 2 N + 4NH'Br. 
 
 1 vol. tribromide of allyl is mixed with about 6 vol. of a solution of ammonia in weak 
 alcohol, and heated to 100 C. in sealed tubes for 10 or 12 hours ; the liquid is then 
 filtered from the separated bromide of ammonium, and the filtrate mixed with a largo 
 quantity of water, whereupon it becomes turbid, and deposits dibromallylamine in the 
 form of a heavy oil, which may be purified by dissolving it in hydrochloric acid, eva- 
 porating to dryness at 100 C., redissolving in water, filtering to separate a small 
 quantity of oil, again evaporating, and treating the residue with ether, in which the 
 hydrochlorate is nearly insoluble. From the salt thus purified, the base is separated 
 by distillation with potash. It is alkaline to test-paper, and forms a cloud with 
 hydrochloric acid : it is however but a weak base, incapable of decomposing the salts 
 of copper or silver. It cannot be distilled without alteration. It is but sparingly 
 soluble in water, but dissolves readily in alcohol and in acids. It has a peculiar sweet 
 and aromatic taste. It does not show much tendency to form crystallisable salts. 
 The sulphate forms a gummy mass. The hydrochlorate is a yellowish salt easily 
 soluble in water and alcohol, sparingly in ether. It tastes like the base itself. It 
 assumes a darker colour at 100 C. and sublimes partially at 160. On adding nitrate 
 of silver to the aqueous solution, the whole of the chlorine is precipitated as chloride of 
 silver, but the bromine remains in solution. The chloroplatinate, C 8 H 9 Br 2 N.HCl.PtCP, 
 is an orange-coloured precipitate nearly insoluble in absolute alcohol. Alcoholic solu- 
 tions of dibromallylamine and chloride of mercury form, when mixed, a copious white 
 precipitate. (Maxwell Simpson, Phil. Mag. [4] xvi. 257.) 
 
 Ethyldibromallylamine, C 8 H 13 Br 2 N = KC 2 H 3 .(C 3 H 4 Br) 2 . Obtained by enclosing 
 dibromallylamine with a large excess of iodide of ethyl in a sealed tube, and heating 
 the mixture to 100 C. for a considerable time. The excess of iodide of ethyl is 
 then distilled off, and the remaining hydriodate of ethylbibromallylamine is dissolved 
 in water and distilled with potash. It has a very bitter and pungent taste, smells 
 like nutmeg, is insoluble in water, soluble in acids, and alkaline to test-paper. It is 
 a stronger base than dibromallylamine, and precipitates oxide of copper from cupric 
 salts. (Simpson.) 
 
 TRIAIXYLAMINE, C 9 H 15 N = N.(C 3 H 5 ) 3 , is formed by the destructive distillation of 
 hydrate of tetrallylium. 
 
 TETRALLYLHIM, C 12 H 20 ]Sr = N(C 3 H 5 ) 4 . The iodide of this base is the chief product 
 of the action of ammonia on iodide of allyl. The action takes place without the aid 
 of heat, a large quantity of the iodide dissolving after a few days' contact; the solution 
 afterwards deposits splendid crystals of the iodide, and sometimes becomes a solid 
 mass. The separation of the crystals may be accelerated by adding a strong solution 
 of potash, in which the iodide is completely insoluble. The iodide is purified by ex- 
 posing it to the air till the potash is converted into carbonate, and then recrystallising 
 from absolute alcohol. Treated with oxide of silver, it yields the hydrated oxide of 
 tetrallylium, and the solution of this oxide mixed with hydrochloric acid and bi- 
 chloride of platinum, forms a yellow salt containing N(C 3 H 5 ) 4 Cl,PtCl 2 . 
 
 Tttrallylarsonium, As(C 3 H 5 ) 4 . "When iodide of allyl is digested with arsenide of 
 
ALL YL ALOES. 147 
 
 potassium, several liquid compounds are formed, having a very fetid odour, and at the 
 same time a solid crystalline body separates, which is the iodide of tetrallyl-arsonium. 
 (Hofmann and Cahours.) 
 
 C 8 H 4 . A diatomic radicle which bears to allyl the same relation 
 that ethylene O'H 4 , bears to ethyl C 2 E 5 . Respecting its properties in the free state and 
 the mode of separating it, see ADDENDA (p. 1112). 
 
 Chloride of Allyl ene, C 3 H 4 .C1 2 . Acroleinchlorid. Obtained by the action of per- 
 chloride of phosphorus on acrolein (p. 56). To prevent the action from becoming too 
 violent, the retort should be externally cooled, the perchloride of phosphorus covered 
 with a layer of oxychloride, and the acrolein added by small portions at a time. The 
 proportions are 1 pt. acrolein to 3 pts. of the perchloride. The crude distillate is shaken 
 up with water to remove oxychloride of phosphorus, and further purified by digestion 
 with chloride of calcium and rectification, the chloride of acrolein passing over at 
 about 90 C. It is a colourless oil, having a sweetish ethereal taste, and an odour like 
 that of chloroform. Specific gravity 1-170 at 27'5 C. Boiling-point (corrected) 84-4 C. 
 Another oily liquid, apparently isomeric with chloride of allylene, is likewise formed 
 by the action of perchloride of phosphorus on acrolein. 
 
 Chloride of allylene is slowly oxidised by nitric acid. Heated with aqueous nitrate 
 of silver, it precipitates chloride of silver. Chlorine converts it into a crystalline com- 
 pound, probably sesquichloride of carbon. Sodium has no action upon it. Heated 
 with ethylate of sodium, it appears to yield a compound corresponding to acetal 
 (p. 3). Heated in a sealed tube with alcoholic potash, it appears to yield the 
 same compound, together with chloride of acryl, C 3 H 3 C1. Heated in a sealed tube with 
 ammonia, it yields sal-ammoniac and acrolein-ammonia (p. 56). (Hiibner and 
 G-euther, Ann. Ch. Pharm. cxiv. 36.) 
 
 Acetate of Allylene, C 7 H 10 4 = /c^Ero) 2 \ 2 ' Acctate of Acrolein. Produced, 
 1. By heating in sealed tubes a mixture of 1 at. acrolein (C 3 H 4 0), and 1 at. acetic 
 anhydride (C 4 H 6 3 .) 2. By heating 1 at. chloride of allylene with 2 at. acetate of 
 silver in a sealed tube, first in the water-bath for several hours, then to 160 C. in 
 an oil-bath, rectifying the product, and collecting apart that which passes over between 
 135 and 160: C 2 H 4 C1 2 + (C 2 H 3 0) 2 .Ag 2 .0 2 = (C 2 H0) 2 .C 8 H 4 .0 2 + 2AgCl. It is a 
 colourless liquid, having a strong fishy odour, and very sharp taste. Specific gravity 
 1-076 at 22 C.; boils at about 180. It slowly reduces an ammoniacal solution of 
 nitrate of silver. Heated with caustic-potash, it yields acrolein and acetate of 
 potassium. It may he regarded as a compound of 1 at. acrolein with 1 at. acetic 
 anhydride, C 8 H 4 O.C 4 H 6 3 . (Hiibner and Geuther.) 
 
 AXiXVXAGRERXTZ:. Native anhydrous sulphate of zinc. (See SULPHATES.) 
 AX.MANDXNX. (See GARNET.) 
 
 AXMOlvrDS, OH OF. Both sweet and bitter almonds yield by pressure a fixed 
 oil, having a light yellow colour, an agreeable taste, but no odour. Specific gravity 0-918 
 at 15. It consists chiefly of olein, with but little solid fats, and consequently requires 
 a very low temperature ( 25 C.) to solidify it. It easily turns rancid. It dissolves 
 in 25 pts. of cold alcohol, in 6 pts. of boiling alcohol, and mixes in all proportions with 
 ether. 
 
 Bitter almonds macerated with cold water and distilled, yield also a volatile oil, of 
 fragrant odour, which is the hydride of benzoyl (C 7 H 5 O.H). This oil does not exist 
 ready formed in the almonds, but is produced by the action of an azotised body, 
 emulsin, on the amygdalin contained in the fruit. Sweet almonds do not contain 
 emulsin, and therefore do not yield the volatile oil. (See BENZOYL, HYDRIDE OF.) 
 
 AXiOERETXC ACID. (See ALOETIC ACID.) 
 
 The thickened juice of various species of aloe, a genus of plants belong- 
 ing to the liliaceous order. It is chiefly extracted from the Aloe soccotrina in Arabia; 
 from Aloe spicata and A. linguiformis at the Cape of Good Hope ; and from A. vulgaris 
 or sinuata in Barbadoes and Jamaica. The best sorts of aloes are prepared by ex- 
 posing to the sun the juice which exudes spontaneously from incisions in the leaves ; 
 inferior kinds are obtained by pressing the leaves. Aloes occurs in commerce in large 
 red-brown masses, having a shining conchoidal fracture ; in thin plates it is red and 
 translucent ; it is easily reduced to a yellow powder. It has an odour like that of 
 saffron, and a very persistent bitter taste. It dissolves completely in alcohol and in 
 boiling wafer. It possesses active purgative properties, due to a crystallisable principle 
 
 L 2 
 
148 ALGETIC ACID ALOUCHI. 
 
 aloin, which is contained in it, and may be extracted in a state of purity from Bar- 
 badoes aloes. 
 
 A3.0ETIC ACID. C* 4 fll!V*0 la ? Polychromio Acid. Artificial Bitter of Aloes. 
 Produced by the action of nitric acid upon aloes, chrysammic acid being formed at 
 the same time (Schunck, Ann. Ch. Pharm. xxxix. 24; Ixv. 235; G-. J. Mulder, 
 J. pr. Chem. xlviii. 39). 1 part of aloes is gently heated with 8 pts. of moderately 
 strong nitric acid till gas begins to escape ; the vessel is then removed from the fire, 
 and as soon as the disengagement of gas ceases, the solution is concentrated by eva- 
 poration, till a yellow powder separates, the quantity of which may be increased by 
 addition of water. The aloetic acid is separated from the chrysammic acid in this 
 powder by treatment with boiling alcohol, which dissolves the aloetic acid ; and on 
 evaporating the solution, the acid is obtained in the form of an orange-yellow powder 
 having a bitter taste. It is but slightly soluble in water, but dissolves more freely in 
 boiling water, forming a solution of a splendid purple colour, which is changed to 
 yellow by nitric acid, but restored by alkalies. It is dissolved by ammonia, potash, 
 and soda, forming purple solutions. Strong nitric acid converts it into chrysammic 
 acid. It is monobasic. The barium-salt, C 7 H s BaN 2 8 , is a brown-red nearly insoluble 
 powder, obtained by precipitating the aqueous acid with acetate of barium. The 
 potassium-salt separates by slow evaporation in crystals of a fine ruby colour. Ac- 
 cording to Schunck, the formula of aloetic acid is C 16 H*N0 13 -, according to Mulder 
 C li H 3 N 2 O u . According to the formula above given, it isisomeric with dinitrobenzoic 
 acid. 
 
 The alcoholic mother-liquor obtained in the preparation above described contains 
 another acid called Aloeretic acid, C 7 H 3 ON 6 ? which, according to Mulder, is the first 
 product of the action of nitric acid on aloes. It is separated by neutralising with 
 chalk, mixing the fLtrate with acetate of lead, decomposing the lead-precipitate with 
 hydrosulphuric acid, and evaporating. It is a brown amorphous mass, which when 
 boiled with nitric acid is converted first into aloetic, then into chrysammip acid. 
 (Mulder.) 
 
 The name aloeretic acid is also applied by Schunck to an acid produced by the action 
 of alkalis on chrysaminic acid, and called by Mulder chrysatric acid (which see). 
 
 AX.OXigr. C 17 H I8 7 , or (7 3 W 8 14 . A crystalline bitter principle obtained from 
 aloes : also called Bitttr of aloes. It is prepared by mixing Barbadoes aloes with sand, 
 to prpvent agglomeration, treating it several times with cold water, and evaporating 
 the aqueous extract in vacuo to the consistence of a syrup. It then separates in small 
 crystals. The solution must not be heated to the boiling-point, since aloin undergoes 
 alteration at 100 C. 
 
 According to Dr. Stenhouse (Phil. Mag. [3] xxxvii. 481), the Cape and Socotriu 
 aloes contain large quantities of foreign matters which prevent the crystallisation of 
 the aloin ; he has succeeded in isolating the aloin, only by operating on the Barbadoes 
 aloes. 
 
 Pure aloin separates from an alcoholic solution, in the form of small prismatic 
 needles, grouped in stars, of a pale yellow colour. Its taste is at first sweet, then 
 extremely bitter. It is much more purgative than aloes itself. In the cold, it is but 
 slightly soluble in water and alcohol, but dissolves better when hot ; the solutions 
 are yellow and neutral to test-paper. Dried at 100C. it contains C 17 H 18 7 . 
 
 The caustic and carbonated alkalis dissolve aloin with a bright yellow colour. 
 
 By digestion with concentrated nitric acid, aloin is transformed into chrysammie 
 acid. Chlorine passed into an aqueous solution of aloin, produces a bright yellow 
 precipitate, chloraldil, containing, according to Eobiquet, C n3 Cl0 5 . Solution of 
 chloride of lime colours aloin bright yellow, this tint passing rapidly to brown. 
 
 Bromine added in excess to a cold aqueous solution of aloin produces a yellow pre- 
 cipitate of bromalo'in, C 17 H' 5 Br 8 7 ? which dissolves in boiling alcohol, and separates 
 iu shining yellow needles, grouped in stars, and much larger than the crystals of aloin. 
 It is less soluble in cold water and alcohol than aloin : the solutions are neutral. 
 
 AZiOXSOXi. C 6 H*0 3 ? An oily liquid obtained in very small quantity by distil- 
 ling aloes with half its weight of quick lime. It is colourless, has a sharp penetrating 
 odour, is insoluble in water, but mixes in all proportions with alcohol and ether. 
 Specific gravity 0'877. Boiling-point 130C. By contact with the air, or by the action 
 of strong nitric acid on chlorine water, it is converted into a brown-red liquid, heavier 
 than water, and having a very decided odour of castorenm. Treated with oxide of 
 copper or chromic acid, it yields carbonic acid, water, and hydride of benzoyl. (Ko- 
 biquet, J. Pharm. [3] x. 167 and 241.) 
 
 AXiOUCXXI, or AZiUCHX RESIST is imported from Madagascar, where it ia 
 
ALPHENE ALUMINIUM. % 1 49 
 
 obtained, according to Valmont de Bomare, from a tree called Timpi. According to 
 others, from Wintcra aromatica. It is friable, whitish on the outside, black within, 
 has a marbled appearance, and a strongly aromatic, peppery, bitter taste. According to 
 Bonastre (J. Pharm. x. 1), it contains 6S'12 p. c. of resin easily soluble in cold 
 alcohol, 20'45 of resin sparingly soluble in cold alcohol, T58 essential oil, together 
 with small quantities of free acid and ammonia-salt, besides earthy impurities. The 
 sparingly soluble resin appears to be of peculiar nature. 
 
 AI.PHENE, SULPHIDE OP. (See SULPHOCYANIDE OF AMMONIUM.) 
 
 AXiSTOCTXTE. A mineral having the same composition as barytocalcite, C0 3 .BaCa. 
 [or BaO.CO* + CaO.CO' 1 -], but crystallising in oblique prisms, whereas baryto-calcite 
 forms right rhombic prisms : hence carbonate of barium and calcium is dimorphous. 
 Alstonite is found on Alston Moor in Cumberland. 
 
 AX.TAITE. (See TEMAJBIDE OF LEAD.) 
 AZiTHEZXT. Syn. of ASPARAGIN. 
 
 AIiTHIONIC ACID. C 2 H 6 S0 4 . This acid, isomeric with ethylsulphuric or 
 sulphovinic acid, is produced, according to Regnault (Ann. Ch. Phys. [2] Ixv. 98), 
 when alcohol is heated with excess of strong sulphuric acid till olefiant gas begins to 
 be evolved (between 160 and 180 C.) When equal parts of sulphuric acid and alcohol 
 are used, nothing but sulphovinic acid is formed, and even in the residues of the ether- 
 preparation on the large scale, the latter is the only acid found. 
 
 To prepare the barium-salt of althionic acid, the residue obtained in the preparation 
 of olefiant gas from 6 pts. sulphuric acid and 1 pt. alcohol, is saturated with milk of 
 lime ; the filtrate, after evaporation, is treated with oxalic acid to precipitate the lime ; 
 the liquid again filtered and saturated with baryta- water ; the excess of baryta preci- 
 pitated by carbonic acid ; and the filtrate evaporated, first by heat, and finally in vacuo, 
 crystallisation then taking place as soon as the liquid acquires a syrupy consistence. 
 The salt when purified by recrystallisation, forms spherules composed of small needles 
 permanent in the air, and giving off 8 '59 p. c. (1 at.) of water in vacuo. The formula 
 of the crystallised salt is C 2 H 3 BaS0 4 + H 2 0. It is more soluble in water than the 
 sulphovinate of barium, and dissolves also in alcohol especially when hot. 
 
 From the aqueous solution of the barium-salt, the free acid (the hydrogen-salt) may 
 be obtained by precipitating the baryta with sulphuric acid, and from this the other 
 salts may be prepared by direct combination. The calcium-salt evaporated at the 
 gentlest possible heat, solidifies completely in a mass, without crystallising. The 
 copper-salt forms pale green, very thin rhombohedrons, having an acute angle of 60. 
 (Regnault.) 
 
 Magnus (Pogg. Ann. xlvii. 523) was not able to find althionic acid in the residues 
 of the preparation of olefiant gas, but only ethionic, isethionic, and sometimes also 
 sulphovinic acid. 
 
 AIiTJDEZiS. Pear-shaped earthern vessels used by the older chemists for sub 
 liming. They are open at each end and fit into 
 one another in the manner shown in fig. 7. At ^' 1 9' ' 
 
 the quicksilver works at Almaden in Spain, vessels 
 of this shape are used to condense the mercurial 
 vapours issuing from the retorts. For this pur- 
 pose they are laid in the form of a chain on a slightly inclined surface called the 
 oludel-bath. (See MERCURY.) 
 
 AZiUXVI. (See SULPHATES.) 
 
 AI.TJ1VIINATES. Compounds of alumina with the stronger bases. 
 
 AIiTTXVIIxaTTE. A basic sulphate of aluminium, A1 4 3 .S0 3 + 9HO, found native 
 at New Haven in America. It is a white, opaque, earthy mass, of specific gravity 
 1705, soluble in hydrochloric acid. Gives off its acid at a red heat. (Stromeyer.) 
 
 ALUIVIITJIUIVT. Symbol, Al ; Atomic weight, 1375. This metal occurs in a 
 great variety of forms, viz. as oxide (alumina) anhydrous, and hydrated, sometimes 
 alone, but more generally associated with the oxides of other metals, iron zinc, 
 glucinum, magnesium, &c. ; as sulphate and phosphate ; as silicate, which is the chief 
 constituent of all clays, and in combination with other silicates, forms a vast, number 
 of minerals, especially the felspars ; also as mellitite, or honeystone, as fluoride of 
 aluminium and sodium in cryolite ; and in very small quantities in plants. 
 
 Alumina was first shown to be a distinct earth by Marggraff in 1754, having 
 been previously confounded with lime. Oerstedt, in 1826, showed how to prepare 
 
 L 3 
 
150 ALUMINIUM. 
 
 the chloride of aluminium by passing chlorine over a red-hot mixture of alumina 
 and charcoal; and Wohler, in 1828 (Pogg. Ann. xi. 136) succeeded in eliminating 
 the metal by igniting the chloride with potassium. It was thus obtained in the form 
 of a grey powder intermixed with tin-white globules arising from partial fusion. It 
 has lately been obtained in the compact form, and in much larger quantity, by 
 H. Sainte-Claire Deville and others. 
 
 Preparation. The mode of preparation now adopted is the same in principle as 
 that of Wohler, depending on the action of sodium at a red heat .on the chloride or 
 fluoride of aluminium, or better, on the double chloride or double fluoride of alumi- 
 nium and sodium. Sodium is used to effect the reduction in preference to potassium, 
 partly because it acts more regularly and with less violence, and partly because it is 
 more easily prepared, and, having a lower atomic weight than potassium, a smaller 
 quantity of it suffices for a given amount of chemical work. 
 
 The process first adopted by Deville consisted in passing the vapour of chloride of 
 aluminium over sodium contained in a tube of iron or copper which was kept at a 
 dull red heat. Metallic aluminium was thus obtained, mixed with chloride of alumi- 
 nium and sodium. The latter was removed by washing with water, and the metallic 
 globules which remained were made to unite by heating them till they began to melt, 
 and pressing them together with a pipe-stem. The mass thus obtained was then 
 remelted and cast into bars. Another method which promised to yield good results, but 
 has not yet been perfected, was to reduce the chloride of aluminium by vapour of 
 sodium. The mixture of carbonic oxide and sodium-vapour produced by heating a 
 mixture of charcoal and carbonate of sodium (see SODIUM) was conveyed into a large 
 earthen crucible by means of an iron tube passing through a hole near the bottom and 
 reaching nearly to the other side ; and as the sodium and carbonic oxide burned and 
 thereby heated the crucible, portions of chloride of aluminium were thrown in from 
 time to time. The crucible when cold was broken, and the aluminium separated 
 from the saline mass in the manner above described. 
 
 The quantity of compact aluminium obtained by these methods was however con- 
 siderably below the theoretical amount, a large portion of the metal being reduced in 
 the form of a fine powder which re-fused to unite into globules. This inconvenience 
 may be obviated and much better results obtained by the use of fluor spar or cryolite 
 as a flux. These fluorides assist the union of the particles, apparently by dissolving 
 small quantities of alumina produced by moisture adhering to the chloride, which 
 surround the particles of metal at the moment of reduction, and, not being decom- 
 posed by the sodium, prevent them from uniting into globules. The reduction may 
 be performed in crucibles, or better, in a reverberatory furnace. 
 
 a. 400 parts of chloride of aluminium and sodium, 200 pts. of chloride of sodium, 
 200 pts. of fluor spar or cryolite the latter being preferable all perfectly dry and 
 finely pulverised, are placed together, with 75 or 80 pts. of sodium, in alternate layers, 
 in an earthen or iron crucible, which is moderately heated till the action begins, 
 and afterwards to redness, the melted mass being stirred with an iron rod and after- 
 wards poured out. If the process goes on well, 20 pts. of aluminium are thus 
 obtained in a compact mass, and about 5 pts. more in globules encrusted in a hard 
 mass. 
 
 The aluminium thus obtained is, however, somewhat contaminated with silicon, 
 derived from the earthy matter of the crucible, which is attacked by the sodium, by 
 the aluminium itself, and by the fluorides in the slag. This evil may be corrected to 
 a certain extent, but not completely, by lining the crucible with a paste composed of 
 calcined alumina, or aluminate of calcium. If iron crucibles are used, the aluminum 
 is found to contain iron. 
 
 b. The reduction is performed with greater facility, and on a much larger scale, 
 by heating the mixture on the hearth of a reverberatory furnace. 
 
 The proportions used are : 
 
 Chloride of aluminium and sodium . . . .10 parts. 
 
 Fluor spar or cryolite . . . . 5 
 
 Sodium . . . . . . 2 
 
 The double chloride and the cryolite or fluor spar are mixed in the state of powder 
 with sodium in small ingots, and the whole is thrown on the hearth of the furnace pre- 
 viously raised to the required temperature. The dampers are then closed to prevent 
 access of air. A vivid action soon takes place, accompanied by evolution of heat, 
 sufficient to raise the walls of the furnace and the mixture itself to bright redness ; 
 and the mixture is almost completely liquefied. When the reduction is complete, the 
 fused mass is run out through an aperture at the back, the slag escaping first, and 
 then the aluminium flowing out in a single jet, and collecting in one mass below the 
 liquid slag. With a furnace having a hearth about 16 square feet in surface, about 
 
ALUMINIUM. 151 
 
 16 Ibs. of aluminium may be obtained at one operation. The slag consists of two 
 layers, the upper containing a large quantity of common salt, while the lower, which is 
 pasty and less fusible, consists chiefly of fluoride of aluminium. On pulverising this 
 latter and passing it through a sieve, an additional quantity of aluminium is obtained 
 in globules. The fluoride of aluminium may be used for the preparation of alumina. 
 
 This process (which has been patented by MM. Kousseau, Freres and M. Paul Morin, 
 both in France and in this country, 1856, No. 1810) is peculiarly advantageous in 
 this respect, that the reduced metal is very little exposed to contamination with silicon. 
 The introduction of this impurity generally arises from the action of the sodium or of the 
 slag on the earthy matters of the vessels in which the reduction takes place. Now, 
 when crucibles are used and the heat is applied from below, the part of the mixture 
 in contact with the crucibles is necessarily the hottest, and consequently the action 
 exerted on the crucible is considerable ; but when the mixture is fused on the hearth 
 of a reverberatory furnace, with the flame playing on its surface, the coolest part is in 
 contact with the hearth, which is therefore less acted upon. Moreover with the pro- 
 portions above given, the whole of the fluorine is separated as fluoride of aluminium, 
 a compound which exerts but little action on silicious substances. 
 
 Preparation from Cryolite. The pulverised mineral is mixed with half its weight 
 of common salt, and the mixture is arranged in alternate layers with sodium (2 pts. 
 of sodium to 5 pts. of cryolite), in an earthen or iron crucible, a layer of pure cryolite 
 being placed at top, and the whole covered with common salt. The mass is rapidly 
 heated till it melts completely, and then left to cool after being stirred with an iron 
 rod. The aluminium is generally found in large globules. Such was the method 
 originally practised by Professor H. Eose in Berlin, and by Dr. Percy and Mr. Allen 
 Dick in this country. It is now carried on, on the manufacturing scale, at Amfreville, 
 near Rouen, by C. and A. Tissier. 
 
 A peculiar apparatus for effecting the reduction of aluminium, either from the 
 double chloride or from cryolite, the object of which is to prevent loss of sodium by 
 ignition, has been invented and patented by F. W. Gerhard (1858, No. 2247). It 
 consists of a reverberatory furnace having two hearths, or two crucibles or reverbe- 
 ratory furnaces placed one above the other, and communicating by an iron pipe. In 
 the lower is placed the mixture of sodium with the aluminium-compound, and in the 
 upper a stratum of chloride of sodium, or of a mixture of sodium and cryolite, or of 
 the slag obtained in a former operation. This layer when melted, is made to run into 
 the lower furnace in quantity sufficient to cover completely the mixture contained 
 therein, so as to protect it from the air. 
 
 The .chief inducement for using cryolite as a source of aluminium, is that it is 
 a natural product obtained with tolerable facility, and enables the manufacturer to 
 dispense with the troublesome and costly preparation of the chloride of aluminium 
 and sodium. But the aluminium thus obtained is less pure than that prepared from 
 the double chloride by the method previously described. If earthen crucibles are 
 used, the aluminium is contaminated with silicon, because the fluoride of sodium pro- 
 duced by the decomposition acts strongly on the silicious matter of the crucible ; and 
 if crucibles of iron are used, the aluminium takes up a portion of that metal. For 
 these reasons, Deville is of opinion, that the best use of cryolite is as a flux in the 
 preparation of aluminium from the double chloride. In that case, as already observed, 
 the slag consists, not of fluoride of sodium, but of fluoride of aluminium, which acts 
 but slightly on the containing vessel. 
 
 Reduction of aluminium by means of hydrogen or carbon. Several attempts have 
 been made, but with doubtful success, to separate aluminium from its compounds by 
 means of the ordinary reducing agents. 
 
 F. W. Gerhard decomposes fluoride of aluminium, or the double fluoride of alumi- 
 nium and potassium or sodium, by subjecting it to the action of hydrogen gas at a 
 red heat. The aluminium-compound is placed in a number of shallow dishes of glazed 
 earthenware, each of which is surrounded by a number of other dishes containing iron 
 filings. These dishes are placed in an oven previously heated to redness ; hydrogen 
 gas is then admitted, and the heat increased. Aluminium is then separated, and 
 hydrofluoric acid evolved, which is immediately taken up by the iron filings, and 
 thereby prevented from acting on the aluminium. To prevent the pressure of gas 
 from becoming too great, an exit-tube is provided, which can be opened or closed at 
 pleasure by means of a stopcock. This process, which was patented in 1856 (No. 2980), 
 is ingenious and was said to yield good results ; the inventor has however since returned 
 to the use of the more costly reducing agent, sodium (see above), which would seem 
 to imply that the hydrogen method has not quite fulfilled his expectations. 
 
 Sir Francis C. Knowles has patented a process (1857, No. 1742) for reducing alu- 
 minium from its chloride by means of cyanide of potassium or cyanide of sodium, the 
 
 L 4 
 
152 ALUMINIUM. 
 
 chloride, either in the fused state or in the form of vapour being brought in contact 
 either with the melted cyanide or its vapour. Pure alumina may be added to increase 
 the product. 
 
 L. F. Corbelli, of Florence, states that aluminium may be obtained by mixing the 
 impure sxilphate (prepared by heating clay with strong sulphuric acid), with 2 pts. of 
 ferrocyanide of potassium, and 1| pt. common salt, and heating the mixture to whiteness. 
 The metal thus obtained must however be very impure, perhaps consisting chiefly of 
 iron. The process was patented in this country in 1858 (No. 142). 
 
 M. Cumenge, of Paris, obtains aluminium from the sulphide (A1 4 S 3 ) either by heat- 
 ing that compound in an atmosphere of hydrogen, or by heating it with alumina or 
 sulphate of- aluminium, in such proportion that the oxygen contained in that com- 
 pound shall be just sufficient to convert the whole of the sulphur into sulphurous 
 anhydride : 
 
 A1 4 S 3 + 2A1 4 3 = 3S0 2 + 12A1 
 or A1 4 S 3 + A1 4 (S0 4 ) 3 = 6S0 2 + 8A1; 
 
 or, lastly, by decomposing the sulphide with an ordinary metal, such as iron, copper 
 or zinc. This process is also patented (1858, No. 461). 
 
 Preparation of Aluminium by Electrolysis. The electrolytic reduction of alumi- 
 nium may be performed either in the dry or in the wet way. The reduction from 
 fused chloride of aluminium and sodium was first effected in this manner by Buns en 
 in 1854 (Pogg. Ann. xcii. 648). The salt is introduced in a fused state into a red- 
 hot porcelain crucible, divided into two parts by a porous earthenware diaphragm, and 
 the extremities of the carbon poles of a Bunsen's battery of ten elements are introduced 
 into the two halves of the fused mass. The metal is then reduced at the negative 
 pole. The heat must be raised considerably above the melting-point of the double 
 chloride, otherwise the aluminium separates in the pulverulent form. It is best to add 
 fresh quantities of chloride of sodium during the reaction, and to raise the tempera- 
 ture ultimately to the melting point of silver. The aluminium is then obtained in 
 globules of considerable size, which may be melted into one by throwing them into 
 chloride of sodium melted at a white heat. Deville adopts a similar method, using, 
 however, platinum instead of charcoal for the negative pole. 
 
 The same method may be used for coating metals with aluminium. Thus, if a bar 
 of copper be used as the negative pole, and a bar of aluminium as the positive pole, 
 tha latter dissolves as the action goes on, and is deposited upon the copper. 
 
 Aluminium may also be reduced by the action of the current from the solution of its 
 salts. Mr. Gore has in this way obtained a deposit of aluminium on copper, and 
 Messrs. Evans and Tilleyhave patented a process (1855, No. 2756), for coating metals 
 with aluminium and its alloys, by electrolysing a solution of alumina mixed with 
 cyanide of potassium, the negative pole being formed of the metal to be coated, and 
 the positive pole of platinum or aluminium, or of some other metal, such as copper, 
 tin or silver, which is to be deposited together with the aluminium. The bath may 
 also in some instances be composed of a mixed solution of aluminium and the other 
 metal to be deposited. M. Corbelli, of Florence, obtains a deposit of aluminium by 
 electrolysing a mixture of rock-alum or sulphate of aluminium with chloride of calcium 
 or chloride of sodium, the positive pole being formed of iron wire coated with an 
 insulating material and dipping into mercury placed at the bottom of the solution, and 
 the negative pole of zinc immersed in the solution. Aluminium is then deposited 
 on the zinc, and the chlorine eliminated at the positive pole unites with the mercury, 
 forming calomel. This process is also patented (1858, No. 507). 
 
 Of all the processes above described, the only one that has been successfully applied 
 to the production of aluminium on the large scale, is the decomposition of the double 
 chloride or of cryolite by sodium. The electrolytic method is too expensive, excepting 
 for producing a thin coating of aluminium on other metals ; and the attempts which 
 have been made to obtain aluminium by means of the ordinary reducing agents, such 
 as hydrogen and charcoal, do not appear to have led to very satisfactory results. At 
 present, therefore, the progress of the aluminium manufacture depends essentially on 
 the economical production of sodium; and indeed the manufacture of aluminium has 
 already given a great stimulus to that of sodium, and has led to considerable improve- 
 ments in that process, and consequent reduction of cost. (See SODIUM.) * 
 
 Purification. Aluminium may be purified from copper and iron by fusion with nitre 
 in an iron crucible, the foreign metals being thereby oxidised, -vhile the aluminium remains 
 
 When Devillp commenced his experiments in 1854, great hopes were entertained that aluminium 
 might be produced at a price sufficiently low to admit of a variety of useful applications. Hitherto these 
 expectations have been b'it imperfectly fulfilled, the metal being still too costly to be applied to other 
 than ornamental purpose*. Still, however, great progress has been niad,e, the price, which in ISnfi was 
 31 per oz., being now reduced to 5s.; and further reduction will doubtless be m.ide as the details of the 
 manufacture are improved. 
 
ALUMINIUM. 153 
 
 intact. Before introducing the aluminium, the inner surface of the crucible should be 
 well oxidised by the action of the nitre. Aluminium containing zinc, may be freed 
 from that metal by melting the alloy in contact with the air. No method has yet 
 been discovered of purifying aluminium from silicon. 
 
 Aluminium is very apt to retain portions of the slag in the midst of which it has 
 been formed, causing the surface, when worked and polished, to exhibit a number of 
 points of inferior lustre, which gradually became more and more conspicuous. The 
 best mode of purification is to melt the metal in an open black lead crucible for a con- 
 siderable time, then remove it from the fire and stir it with an iron skimmer oxidised 
 on the surface. By this means, the whitish slaggy matter is removed, together with a 
 small portion of the aluminium, which may be set aside to be remelted. The metal is 
 then cast into bars, and the whole operation repeated three or four times. 
 
 [For further information respecting the preparation of aluminium, see De F 'Aluminium, 
 par H. Sainte-Claire Deville, 8vo. Paris, 1859; L' Aluminium et les Metaux Ahalins, 
 par C. et A. Tissier, 12mo. Paris et Rouen, 1858 ; Chemical Technology, by Richard- 
 eoii and Watts, v l- * P* ** P- 1 Ure's Dictionary of Arts, Manufactures and 
 Mines, vol. i. p. 120.] 
 
 Properties. Aluminium is a white metal, with a faint tinge of blue. It takes a fine 
 polish, and its surface may be frosted, like that of silver, by plunging it for an instant 
 into a very weak solution of caustic soda, washing with a large quantity of water, and 
 then digesting it in strong nitric acid. When pure, it is quite destitute of taste and 
 odour. It is very malleable and ductile ; may be beaten and rolled as easily as gold 
 and silver, and drawn out into extremely thin wire. In this last operation, however, 
 it becomes very brittle, and requires to be tempered by cautiously heating it over a 
 lamp. In elasticity and tenacity, it is about equal to silver. After fusion it is as soft 
 as pure silver ; but after hammering in the cold, it acquires the hardness of soft iron 
 It is highly sonorous, a bar of the metal suspended by a thread and struck with a 
 hard body, emitting a beautifully clear, ringing sound. It is very light, being not much 
 more than 2| times as heavy as water, and about 4 times lighter than silver. Its 
 density after fusion is 2'56, and after being hammered in the cold, 2 '67. Its melting- 
 point is intermediate between the melting-points of zinc and silver, but nearer to the 
 former. It may be cast with the greatest ease in metallic moulds, and still better in 
 moulds of sand. It may be fused without any flux ; indeed, the addition of a flux 
 is rather detrimental than otherwise, the metal attacking borax and glass with 
 facility. Aluminium, heated in a closed vessel, does not exhibit the slightest tendency 
 to volatilise. 
 
 The electric conducting power of aluminium is eight times as great as that of iron, 
 and about equal to that of silver ; it conducts heat even better than silver. Its specific 
 heat is very great, and hence, though its melting-point is comparatively lo.w, it takes 
 a long time to liquefy. The melting together of small pieces of the metal may be 
 facilitated by shaking the crucible and pressing them together with an iron rod oxi- 
 dised on the surface. When slowly cooled from fusion, it exhibits a crystalline 
 structure ; the crystallisation is, however, most distinct when the metal is impure. 
 Aluminium precipitated from its solutions by electrolysis at low temperatures, crys- 
 tallises in octahedrons, which appear to be regular. It is slightly magnetic. 
 
 Aluminium does not oxidise in the air, even at a strong red heat ; neither does it, 
 in the compact state at least, decompose water, excepting at a white heat, and even 
 then but slowly (Deville). It is not attacked by sulphuretted hydrogen, or even by 
 sulphide of ammonium, and consequently preserves its lustre in the atmosphere of 
 large towns, where silver is very soon tarnished and blackened. It may also be heated 
 to redness in vapour of sulphur without showing any disposition to combine ; at very 
 high temperatures, however, combination takes place. 
 
 Aluminium is not attacked by nitric acid, either dilute or concentrated, at ordinary 
 temperatures, and very slowly even at the boiling heat ; neither is it acted upon by 
 sulphuric acid diluted to the degree at which that acid dissolves zinc ; but hydro- 
 chloric acid, either dilute or concentrated, dissolves it readily, even at low temperatures, 
 with evolution of hydrogen. The vegetable acids, such as acetic and tartaric acid, 
 exert no perceptible action on aluminium ; a mixture of acetic acid and common salt 
 exerts a somewhat greater action, because it contains free hydrochloric acid ; but even 
 in this case the action is very slow, and not nearly so great as would be exerted- upon 
 tin under similar circumstances. Aluminium would therefore be well adapted for 
 culinary vessels, especially as the small quantity of alumina which might be formed from 
 it by the action of certain acid mixtures would not exert any deleterious action on the 
 animal economy. 
 
 The hydrates of potassium and sodium in the state of fusion do not act upon alu- 
 minium, but their aqueous solutions dissolve it readily, forming aluminate of potassium 
 or sodium, and giving off hydrogen. Ammonia acts but slightly on it. 
 
154 ALUMINIUM. 
 
 A solution of common salt or chloride of potassium is also without action on alumi- 
 nium, but the solutions of many other chlorides dissolve it, and more readily, as the 
 metals which they contain are higher in the scale ; even a solution of chloride of 
 aluminium dissolves the metal, forming a basic chloride. Solutions of sulphates and 
 nitrates, on the contrary, do not act upon it. Hence in precipitating other metals upon 
 aluminium by electrolytic action, it is necessary to use acid solutions not containing 
 hydrochloric acid or any chloride. In an acid solution of sulphate of copper, the 
 aluminium quickly becomes coated with metallic copper. 
 
 Aluminium may be fused with nitre at a moderate heat, without undergoing the 
 slightest alteration ; hence this process may be adopted for purifying aluminium from 
 admixtures of other metals. If however the heat be raised till the nitric acid is com- 
 pletely decomposed and begins to give off nitrogen, a new reaction takes place at- 
 tended with incandescence, and aluminate of potassium is formed. 
 
 Uses. The lustre and whiteness of this metal, its unalterability in the air, and the 
 facility with which it takes a frosted surface, render it well adapted for jewellery, for 
 which purpose it is now much used. It also makes very bright reflectors. Its light- 
 ness renders it useful for mounting astronomical instruments, especially sextants. It 
 may also be used for making small weights, such as the divisions of the gramme. 
 Very delicate balance-beams have also been constructed with it. For culinary vessels 
 it is adapted by its lightness and the little tendency which it has to become corroded 
 by any of the liquids likely to come in contact with it. It is necessary however to 
 observe, that this power of resisting the action of corroding agencies, and more espe- 
 cially those of the atmosphere of large towns, is exhibited only by the pure metal. 
 Now, much of the aluminium of commerce is very impure, being contaminated with 
 iron or silicon, or not having been properly freed from slag. Aluminium thus con- 
 taminated soon becomes tarnished, and much disappointment has been experienced 
 from this cause by many who have used it for ornamental purposes. According to 
 Deville, the impurities just mentioned are found to the greatest amount in the metal 
 obtained from cryolite (p. 152). 
 
 General Characters and Reactions of Aluminium-compounds. Aluminium forms 
 only one class of salts, and into these it is supposed to enter as a sesqui-equivalent 
 radicle, 2 atoms of aluminium taking the place of 3 atoms of hydrogen : Al 2 = H 3 , or 
 A1S '= H. Thus, the chloride of aluminium is (A1 2 )'"C1 3 ; the oxide (alumina) is 
 
 m; the sulphate, (A1 4 )*.3S0 4 , or o*, &c. These formulae are 
 
 1 } > . (A 1 ) ) 
 
 based upon the isomorphism of the aluminium-compounds with other compounds of 
 corresponding character, which are known or supposed to contain sesqui-equivalent 
 radicles : thus, alumina, the only known oxide of aluminium, is isomorphous with 
 scsiiiitoxide of iron and sesquioxide of chromium; and common potash-alum 
 (A1 2 )'"K'(S0 4 ) 2 + 12H 2 0, is isomorphous with iron-alum (Fe 2 )'"K'.(S0 4 )- + 12IFO, 
 and chrome-alum (Cr 2 )'"K'.(S0 4 ) 2 + 12H 2 0. All these formulae may, however, ho re- 
 duced to others containing mono-equivalent radicles, the values of which are two-thirds 
 of those of the corresponding sesqui-equivalent radicles. For instance, the aluminium- 
 compounds may be supposed to contain a radicle (aluminicum), al = A1 = f . 13 ~75 
 10-31. The formula of the chloride will then be aid; that of alumina, al 2 ; that of 
 the sulphate /-S0 4 ; that of alum, afK.SO 4 . It is sometimes convenient to write the 
 formulae in this manner. 
 
 Most compounds of aluminium are colourless. The oxide, hydrates, borates, phos- 
 phates, arseniates, and silicates, are insoluble in water; most other aluminium-com- 
 pounds are soluble. All of these, excepting the silicates, are soluble in hydrochloric 
 and sulphuric acid, at least if they have not been strongly ignited. 
 
 The aqueous solutions have an acid reaction, and an astringent disagreeable taste. 
 They are not precipitated by any free acid. With sulphide of ammonium and other 
 soluble sulphides, they give a white gelatinous precipitate of trihydrate of aluminium, 
 the formation of which is attended with evolution of hydrosulphuric acid gas. The 
 precipitate is insoluble in excess of that reagent, but soluble in caustic potash or soda. 
 With solution of potash or soda, the same gelatinous precipitate of the hydrate is pro- 
 duced, soluble in excess of the alkali, and reprecipitated by boiling with sal-ammoniac, 
 or by cautious neutralisation with hydrochloric acid. With ammonia, the same preci- 
 pitate, insoluble in excess. With alkaline carbonates, the same, carbonic acid being 
 given off, and not entering into combination with the alumina. Withfcrrocyani.de of 
 potassium, a white gelatinous precipitate, after some time. With phosphate of sodium, 
 gelatinous precipitate, closely resembling the hydrate in appearance, and dissolving 
 with the same facility in hydrochloric acid and in potash. From these solutions it is 
 precipitated in the same manner as the hydrate, viz. from the hydrochloric acid solu- 
 tion by ammonia, and from the potash-solution by sal-ammoniac ; it is distinguished 
 
ALUMINIUM (ALLOYS). 155 
 
 from the hydrate however, by its insolubility in acetic acid, and by exhibiting certain 
 reactions of phosphoric acid (q. v.) 
 
 Most compounds of aluminium, when moistened with a small quantity of nitrate of 
 cobalt, and ignited before the blowpipe, exhibit a fine characteristic blue colour. This 
 character is best exhibited by placing a small quantity of alumina, precipitated as 
 above, on charcoal or platinum-foil, heating it to redness, then moistening with nitrate 
 of cobalt, and igniting again. 
 
 Quantitative Estimation of Aluminium. Aluminium is usually precipitated in the 
 form of hydrate by excess of ammonia or carbonate of ammonium, or better by sul- 
 phide of ammonium, because an excess of ammonia or its carbonate dissolves a 
 small but perceptible quantity of the hydrate, which can then be reprecipitated only 
 by boiling the liquid till every trace of ammonia is expelled. The precipitate when 
 ignited leaves anhydrous alumina, containing 53'26 per cent, of the metal. 
 
 Aluminium may also be very conveniently separated from its solutions by boiling 
 with hyposulphite of sodium; alumina is then precipitated together with sulphur, 
 while sulphurous acid is expelled, and a sodium-salt of the acid previously combined 
 with the alumina remains in solution : thus, if the aluminium exists in solution as 
 sulphate : 
 
 S 3 12 A1* + 3S 2 3 Na 2 = A1 4 3 + 3S + 3S0 2 + 3S0 4 Na 2 . 
 
 The liquid should be dilute, and must be boiled till it no longer smells of sulphurous 
 acid ; the alumina then separates quickly in a compact mass, not at all gelatinous, and 
 very easy to wash. The sulphur mixed with it is very easily expelled by ignition. 
 (G-. Chancel, Compt, rend. xlvi. 987.) 
 
 This mode of precipitation by hyposulphite of sodium, serves also to separate 
 aluminium from many metals, especially from iron, the latter metal being reduced to the 
 state of protoxide, and remaining in solution as a sodio-ferrous hyposulphite. To 
 ensure complete separation, the solution must be nearly saturated, if necessary, with 
 an alkaline carbonate, diluted to a considerable extent, and mixed with the hypo- 
 sulphite while cold ; otherwise the alumina separates too quickly, before the iron is 
 completely reduced to protoxide, and then carries some of the iron down with it. 
 After the separation of the alumina, the iron is re-oxidised by nitric acid and preci- 
 pitated by ammonia. (Chancel.) 
 
 Aluminium may also be separated from the alkalis and alkaline earths, by .precipi- 
 tation with ammonia or sulphide of ammonium. In thus separating it from the 
 alkaline earths, however, care must be taken to protect the solution from the air, 
 otherwise carbonic acid will be absorbed by the excess of ammonia, and will preci- 
 pitate the alkaline earth together with the alumina. From barium, aluminium is 
 most easily separated by sulphuric acid. 
 
 Alloys of Aluminium. Aluminium forms alloys with most metals. With zinc 
 and tin it unites readily, forming brittle alloys ; with cadmium it forms a malleable 
 alloy. With iron, aluminium unites in all proportions, forming alloys which are 
 hard, brittle, and crystallise in long needles, when the proportion of iron amounts 
 to 7 or 8 per cent. Aluminium containing iron dissolves in acids more readily than 
 the pure metal. (Deville.) 
 
 Aluminium alloyed with even a small proportion of silver, loses all its malleability. 
 An alloy containing 5 per cent, of silver may, however, be worked like the pure 
 metal, and has been used for making knife-blades. An alloy containing 3 per cent. 
 of silver is used for casting ornamental articles. It has the colour and lustre of silver, 
 and is not tarnished by sulphuretted hydrogen. (Deville.) 
 
 The alloys of aluminium and copper are of especial importance. One in particular, 
 containing 10 pts. of aluminium with 90 pts. of copper, called aluminium-bronze, 
 possesses very remarkable properties. It is a definite compound, containing Cu 9 Al. 
 It has the colour of gold, takes a high polish, is extremely hard, and possesses a 
 tenacity equal to that of the best steel ; it is also very malleable. Another alloy con- 
 taining only 2 Or 3 per cent, of copper, is used for casting ornamental articles of large 
 dimension, intended to be chased. Aluminium may be easily plated on copper. The 
 plates of the two metals are prepared in the usual manner, and well rubbed with sand, 
 then placed between two plates of iron, the whole being well bound together, heated 
 to low redness, and then strongly pressed. (Deville.) 
 
 Alloys of aluminium may be prepared by heating a mixture of alumina and the 
 oxide of another metal, such as copper, iron, or zinc, or a mixture of alumina with 
 carbon and the other metal in the free state, granulated copper, for instance, the 
 materials being all very finely divided, and mixed in atomic proportions ; or rather 
 with the carbon slightly in excess. This method, due to a foreign inventor, has been 
 patented in this country in the name of E. L. Benzon (1858, No. 2753). 
 
1.56 ALUMINIUM. 
 
 Amalgamation and Gilding of Aluminium. According to Cailletet, aluminium may 
 be amalgamated by the action of ammonium-amalgam or sodium-amalgam and water, 
 also when it is connected with the negative pole of the voltaic battery, and dipped 
 into the mercury moistened with acidulated water, or into nitrate of mercury. 
 Ch. Tissier (Compt. rend. xlix. 56), confirms this statement respecting the amalgamation 
 of aluminium in connection with the negative pole of the battery, and adds, that if 
 the aluminium foil is not very thick, it becomes amalgamated throughout, and very 
 brittle. The same chemist finds that aluminium may be made to unite with mercury. 
 merely by the use of a solution of caustic potash or soda, without the intervention of 
 the battery. If the surface of the metal be well cleansed and moistened with the 
 alkaline solution, it is immediately melted by the mercury and forms a shining amal- 
 gam on the surface. 
 
 The amalgam of aluminium instantly loses its lustre when exposed to the air, 
 becoming heated and rapidly converted into aluminium and metallic mercury. It 
 decomposes water, with evolution of hydrogen, formation of alumina, and deposition 
 of mercury. Nitric acid attacks it with violence. (Tissier.) 
 
 To gild aluminium, 8 grammes of gold are dissolved in aqua regia, the solution is 
 diluted with water and left to digest till the following day, with a slight excess of 
 lime ; after being well washed, it is treated at a gentle heat with a solution of 20 grms. 
 of hyposulphate of sodium. The filtered liquid serves for the gilding of aluminium, 
 without the aid of heat or electricity, the aluminium being simply immersed in it, after 
 having been well cleaned by the successive use of potash, nitric acid, and pure water. 
 (Tissier.) 
 
 It is somewhat difficult to solder aluminium, partly because no flux has yet been 
 found that will clean the surface without attacking either the aluminium or the solder, 
 partly because the surface of the aluminium is not easily melted by metals more fusible 
 than itself. An imperfect soldering may indeed be effected by means of zinc or tin, 
 but a better method, devised by M. Hulot, is to coat the aluminium with copper, by 
 the electrolytic method, and then solder in the ordinary way. (Devi lie.) 
 
 Arsenide of Aluminium. (See ARSENIDES.) 
 
 Boride of Aluminium. Boron unites with aluminium under the same circum- 
 stances as silicon (p. 160), and alters its properties in a similar manner. 
 
 Bromide of Aluminium, APBr 3 , is obtained by the action of bromine on pulveru- 
 lent aluminium, the metil being in excess. By sublimation, it is obtained in white, 
 shining laminae, which melt at 90, forming a mobile liquid which boils at about 265 C. 
 It is decomposed when heated in contact with the air. It dissolves in bisulphide of 
 carbon, forming a solution which fumes strongly in the air. It dissolves in water, 
 and the solution evaporated in vacuo over oil of vitriol, leaves needle-shaped crystals 
 containing APBr 3 + 6H 2 0. With bromide of potassium, it forms the double salt 
 KBr.APBr 3 . It absorbs ammonia and hydrosulphuric acid, forming compounds which 
 are decomposed by heat. (R. Weber, Pogg. Ann. ciii. 254.) 
 
 Chloride of Aluminium, APC1 3 . The finely divided metal heated to redness in 
 a current of dry chlorine gas, takes fire and is converted into the chloride, which 
 sublimes (Wohler). The compound is also produced bypassing dry chlorine over 
 an ignited mixture of alumina and charcoal : and this is the method adopted for pre- 
 paring it. Hydrate of aluminium precipitated from a hot solution of alum by an 
 alkaline carbonate is made up into small pellets with oil and lampblack, and the mix- 
 ture is strongly ignited in a crucible : the oil is then decomposed and an intimate 
 mixture of alumina and charcoal remains. This is introduced into a porcelain tube 
 or tubulated earthen retort placed in a furnace, and connected at one end with an 
 apparatus for evolving chlorine, and at the other with a dry receiver. On raising the 
 heat to bright redness, and passing chlorine through the apparatus, chloride of 
 aluminium is formed and condenses in a solid mass in the receiver. 
 
 A similar process is adopted in preparing the compound on the large scale. Alu- 
 mina or clay is mixed with coal, pitch, tar, resin, or any organic substance that will 
 decompose by heat and leave a considerable quantity of charcoal, and the mixture, 
 after being well calcined, is heated to redness in a cylinder of earthenware or cast 
 iron, through which a current of dry chlorine is made to pass. The vapours of 
 chloride of aluminium pass into a condensing chamber lined with plates of glazed 
 earthenware, on which the chloride collects in the solid state. If clay containing 
 a considerable proportion of iron is used in the preparation, it must first, after 
 ignition with carbonaceous matter whereby the iron is reduced to the metallic 
 state be treated with a dilute acid to dissolve out the iron, then washed and dried. 
 
 Chloride of aluminium is a transparent waxy substance having a crystalline struc- 
 ture like talc. It is colourless when pure, but generally exhibits a yellow colour, due 
 
ALUMINIUM (CHLORIDE OXIDE) 1 57 
 
 perhaps to the presence of iron. It is fusible in large masses, and according to 
 Liebig, boils at about 180 C. A small quantity volatilises immediately when heated. 
 It fumes in the air, and smells of hydrochloric acid. It is decomposed at a heat 
 below redness by potassium or sodium, aluminium being set free. When it is dis- 
 tilled with sulphuric anhydride, sulphurous anhydride and chlorine are given off and 
 sulphate of aluminum remains. (H. Kose.) 
 
 2 ATOP + 6S0 3 = A1 4 (S0 4 ) 3 + 3S0 2 + 601. 
 
 Chloride of aluminium is very deliquescent, and dissolves readily in water. The 
 solution left to evaporate in a warm dry place, yields the hydrated chloride A1 2 C1 3 . 
 6H-0 in six-sided prisms. The same solution is formed by dissolving alumina in 
 hydrochloric acid. The anhydrous chloride cannot be obtained by heating the 
 hydrated chloride, because the latter is thereby resolved into alumina and hydro- 
 chloric acid. 
 
 Chloride of Aluminium and Sodium, NaCl.ATOl 3 , is obtained by fusing together 
 the component chlorides in the proper proportions ; by passing the vapour of chloride 
 of aluminium over fused chloride of- sodium ; or by adding the proper quantity of 
 chloride of sodium to the mixture of alumina or aluminiferous matter and carbon used 
 for the preparation of chloride of aluminium, and igniting the mass in an atmosphere 
 of dry chlorine or hydrochloric acid, and condensing the vapour in the same manner as 
 that of the simple chloride. It is a crystalline mass which melts at 200 C., and 
 crystallises on cooling. It is perfectly colourless when pure, much less deliquescent 
 than chloride of aluminium, and being quite fixed at ordinary temperatures, may be 
 handled with facility. These qualities render it much more convenient than the 
 simple chloride for the preparation of aluminium. When ignited with sodium, it 
 yields nearly the theoretical quantity (14 p. c.) of aluminium. 
 
 Fluoride of Aluminium, APF 3 , is produced by the action of gaseous fluoride of 
 silicon on aluminium. The product is at first mixed with reduced silicon, but this 
 may be easily removed by digestion with a mixture of hydrofluoric and nitric acids. 
 Fluoride of aluminium then remains in a colourless mass of cubical crystals, which 
 have but little refracting power. It volatilises at a bright red heat, is insoluble in 
 water, and resists the action of all acids. (Deville, Compt. rend, xliii. 49.) 
 
 Fluoride of Aluminium and Potassium, 3KF.APF 8 , is obtained as a gelatinous pre- 
 cipitate by dropping a solution of fluoride of aluminium into a solution of fluoride of 
 potassium, till the latter remains in only slight excess. A precipitate of similar cha- 
 racter, but consisting of 2KF. A1 2 F 3 , is obtained by stirring up a solution of fluoride of 
 aluminium with a quantity of fluoride of potassium not quite sufficient for complete 
 saturation. Both precipitates dry up to white powders, and give off the whole of 
 their fluorine as hydrofluoric acid when heated with sulphuric acid. (Berzelius.) 
 
 Fluoride of Aluminium and Sodium, 3NaF.Al 2 F 3 . Found native as Cryolite, and 
 prepared artificially by pouring hydrofluoric acid in excess on a mixture of calcined 
 alumina and carbonate of sodium in the proportions indicated by the formula, then 
 drying and fusing the mixture. Cryolite belongs to the quadratic or dimetric sys- 
 tem. It is colourless and transparent, softer than felspar, of specific gravity 2 -96, 
 melts below a red heat, and forms an opaque glass on cooling : so likewise does the 
 artificially prepared salt. It is found in large quantity at Evigtok in Greenland, but 
 has not hitherto been discovered in any other locality. It is used, as already 
 described, for the preparation of aluminium, and also in Germany for the manufacture 
 of soda for the use of soap-boilers. 
 
 Iodide of Aluminium, Al 2 ! 3 , is obtained by heating the metal with iodine or iodide 
 of silver in sealed tubes. After repeated sublimation over metallic aluminium, it 
 forms a snow-white crystalline mass, which melts at about 185 C., and boils at a tem- 
 perature above the boiling-point of mercury. It resembles the bromide in most of its 
 properties. With water it forms the hydrate AFI 3 .6H 2 0, which may also be obtained 
 by dissolving hydrated alumina in hydriodic acid. It forms double salts with the 
 alkaline iodides, and absorbs ammonia, forming a snow-white powder. It does not 
 appear to combine with hydrosulphuric acid. (Weber, Pogg. Ann. cvii. 264.) 
 
 Oxide of Aluminium. Alumina, Al'O 3 , or Al*0 3 . This, which is the only 
 known oxide of aluminium, is formed by the direct combination of the metal with 
 oxygen. Aluminium in the massive state does not oxidise, even at a strong red heat ; 
 but in the state of powder it burns brightly when heated to redness in the air or in 
 oxygen gas, and is converted into alumina, 53*3 pts. of the metal taking up 46-69 
 pts. of oxygen to form 100 pts. of alumina. The atomic constitution of alumina 
 cannot be determined from this or any other direct experiment, because there is no 
 other oxide of aluminium with which to compare it ; but it is inferred to be a sesqui- 
 
158 ALUMINIUM (OXIDE). 
 
 oxide, because it is isomorphous with the sesquioxides of iron and chromium, and is 
 capable of replacing those oxides in combination in any proportion. 
 
 Alumina occurs native, and very nearly pure, in the form of corundum, varieties of 
 which, distinguished chiefly by their colour, are the sapphire, ruby, oriental topaz, 
 oriental amethyst, &c. The colourless variety is called hyaline corundum. The crys- 
 talline forms of these gems all belong to the rhombohedral or hexagonal system, tiie 
 primary form being a rather acute rhombohedron. Alumina in the crystalline state 
 has a specific gravity of about 3*9, and is, next to the diamond, the hardest sub- 
 stance known. An opaque variety of corundum called emery, which has a brown 
 red colour, arising from oxide of iron, is much used in the state of powder for polish- 
 ing glass and precious stones. 
 
 Alumina is prepared artificially : 1. By precipitating a boiling solution of common 
 alum (sulphate of aluminium and potassium), free from iron, with carbonate of am- 
 monium, washing the precipitate with water, and igniting it to expel the combined 
 water. 2. By igniting sulphate of aluminium or ammonia-alum. In the former case, 
 sulphuric anhydride is given off ; in the latter, that compound, together with sulphate 
 of ammonium, and alumina remains : 
 
 A1 4 .3S0 4 r= A1 4 3 + 3S0 3 
 and 2(A1 2 .NH 4 .2S0 1 ) = A1 4 3 + (NH 4 ) 2 .S0 4 + 3S0 3 . 
 
 Alumina thus prepared is apt however to retain a small quantity of sulphuric acid, 
 and if the original salt contained iron, the whole of that impurity remains in the 
 residue. 3.* By digesting clays, felspathic rocks, or other minerals containing alumina 
 in a strong solution of caustic potash or soda, assisting the action, if necessary, by 
 boiling under pressure, or by heating the same minerals with kelp or soda-ash in a 
 reverberatory furnace, and lixiviating the fused product with water. A solution of 
 aluminate of potassium or sodium is thus obtained, a silico-aluminate of the alkali 
 generally remaining un dissolved and the alumina may be precipitated from the solu- 
 tion as a hydrate by passing carbonic acid through the liquid ; by treating it with 
 acid carbonate of sodium, or with neutral or acid carbonate of ammonium ; by saturating 
 with an acid (using by preference the last vapours of hydrochloric acid evolved in the 
 manufacture of that compound) ; by treating it with chloride of ammonium, where- 
 upon, ammonia is evolved, chloride of potassium or sodium remains in solution, and 
 alumina is precipitated ; or by mixing the solution of the alkaline aluminate with 
 chloride of aluminium, the result being the precipitation of the alumina from both 
 compounds : 
 
 A1 2 K 3 3 + APC1 3 = A1 4 3 + 3KC1. 
 
 4. By mixing cryolite with rather more than f of its weight of quick lime, adding a 
 small quantity of water to slake the lime, then a larger quantity, and heating the 
 mixture by a current of steam. The products of this operation are fluoride of calcium 
 and aluminate of sodium : 
 
 APNa'T 6 + 3Ca 2 = 6CaF + Al 2 Na 3 3 
 Cryolite. 
 
 The aluminate of sodium is decanted from the heavy deposit of fluoride of calcium, and 
 decomposed by carbonic acid as above. If any insoluble aluminate of calcium should 
 be formed, it may be decomposed by digestion with carbonate of sodium. (Deville.) 
 
 5. The slag obtained in the preparation of aluminium from chloride of aluminium 
 and sodium, with fluor-spar or cryolite as a flux (p. 150), contains about 40 per 
 cent, of fluoride of aluminium, together with soluble chlorides ; and the residue of the 
 extraction of sodium by Deville' s process (see SODIUM), which consists in igniting a 
 mixture of carbonate of sodium, carbonaceous matter and chalk, contains about 14-5 p. c. 
 carbonate of sodium, 8'3 p. c. caustic soda, and 29'8 p. c. carbonate of calcium. Now, by 
 heating to redness a mixture of 5 or 6 pts. of the sodium-residue with 1 pt. of the 
 aluminium-slag, freed by washing from the soluble constituents, and lixiviating 
 the product after cooling, a solution of aluminate of sodium is obtained which may be 
 decomposed by carbonic acid as above. (D eville.) 
 
 Alumina prepared by any of the preceding processes contains iron. From this it 
 may be purified by dissolving it in caustic alkali and precipitating the iron by a 
 stream of sulphuretted hydrogen (Deville). It may then be reprecipitated by car- 
 bonic acid. The alumina thus precipitated always contains a certain quantity of 
 
 * This process, the invention of M. L- Chatelier of Paris, is patented in this country in the name of 
 H. F. Newton, 1858, No. 198S, and 185<j, No. 957. 
 
ALUMINIUM (OXIDES AND HYDRATES). l->9 
 
 alkaline carbonate, which cannot be removed by washing with water. It may, how- 
 ever, be separated by digestion, with the aid of heat, in a small quantity of dilute 
 hydrochloric or nitric acid, or by digestion with chloride of aluminium in excess. 
 (Le Chatelier.) 
 
 Artificially prepared alumina is white, and if it has been exposed only to a moderate 
 red heat, is very light and soft to the touch ; but after strong ignition, it cakes 
 together, becomes so hard as scarcely to be scratched with a file, and emits sparks 
 when struck with steel. According to H. Kose (Pogg. Ann. Ixxiv. 430), the specific 
 gravity of alumina ignited over a spirit-lamp is between 3'87 and 3'90; after six 
 hours' ignition in an air furnace, it is between 3'725 and 375 ; and after ignition in a 
 porcelain furnace, 3*999, which agrees very nearly with that of native corundum. 
 
 Alumina is infusible at all temperatures below that of the oxy-hydrogen flame ; but 
 at that degree of heat, it melts into transparent globules which assume a crystalline 
 structure on cooling. If a small quantity of chromate of potassium be added before 
 fusion, the melted alumina on cooling retains a deep red colour, and resembles the 
 natural ruby. When a mixture of 1 pt. of alumina and 3 or 4 pts. of anhydrous 
 borax is exposed for a considerable time to the high temperature of a porcelain fur- 
 nace, the alumina dissolves in the fused borax, and as the borax is volatilised by the 
 heat, remains in crystals resembling corundum ; in this case also, the addition of a 
 very small quantity of chromate of potassium causes the crystals to exhibit the colour 
 of the ruby. This method is applicable to the artificial formation of a great number 
 of crystallised minerals. (Ebelmen, Ann. Ch. Phys. [3] xxii. 211.) 
 
 Alumina is not decomposible by heat alone. Potassium at a white heat deoxidises 
 it partially, forming an alloy of potassium and aluminium which decomposes water. 
 It is not decomposed by chlorine at any temperature, unless it be mixed with charcoal, 
 in which case a chloride of aluminium is produced. 
 
 Anhydrous alumina is perfectly insoluble in water. After strong ignition, it is like- 
 wise insoluble in most acids, c6ncentrated hydrochloric or sulphuric acid being alone 
 able to dissolve it. In the crystallised state it is insoluble in all acids. It may, how- 
 ever, always be rendered soluble by fusion with hydrate of potassium or sodium. 
 
 HYDBATES or AI/UMINIUM, or OF ALUMINA. These compounds are three in num- 
 ber, viz. : 
 
 Monohydrate .... A1 2 H0 2 or APO\HO. 
 
 Dihydrate A1 4 H 4 S APO\1HO. 
 
 rate . ... A1 2 H 3 3 ,, AP0 3 .3HO. 
 
 JJmydral 
 Trihydre 
 
 The monohydrate is found native as Diaspore, a mineral which forms translucent 
 granular masses of specific gravity 3 '43, and crumbles to powder when heated, but 
 does not give off the whole of its water below 360 C. It is insoluble in water, and 
 even in boiling hydrochloric acid. 
 
 The trihydrate is the ordinary gelatinous precipitate, obtained by treating solutions 
 01 aluminium-salts, alum, for example, with ammonia or alkaline carbonates ; it is also 
 thrown down from the same solutions by sulphide of ammonium, the aluminium not 
 entering into combination with the sulphur. When dried at a moderate heat, it forms 
 a soft friable mass, which adheres to the tongue and forms a stiff paste with water, 
 but does not dissolve in that liquid. At a strong red heat, it parts with its water, and 
 undergoes a very great contraction of volume. It dissolves with great facility in acids, 
 and in the fixed caustic alkalis. When a solution of alumina in caustic potash is 
 exposed to the air, the potash absorbs carbonic acid, and the trihydrate of aluminium 
 is then deposited in white crystals which are but sparingly soluble in acids. 
 
 The trihydrate of aluminium has a very powerful attraction for organic matter, and 
 when digested in solutions of vegetable colouring matter, combines with and carries 
 down the colouring matter, which is thus removed entirely from the liquid if the 
 alumina is in sufficient quantity. The pigments called lakes are compounds of this 
 nature. The fibre of cotton impregnated with alumina acquires the same power of 
 retaining colouring matters ; hence the great use of aluminous salts as mordants to 
 produce fast colours. (See DYEING.) 
 
 Trihydrate of aluminium occurs native as Gibbsite, a stalactitic, translucent, fibrous 
 mineral, easily dissolved by acids. 
 
 Dihydrate of Aluminium, A1 4 H 4 5 , or A1 4 3 ,2H 2 0. When a dilute solution of diace- 
 tate of aluminium is exposed for several days to a temperature of 1 00 C. in a close vessel, 
 the acetic acid appears to be set free, although no precipitation of alumina takes place. 
 The liquid acquires the taste of acetic acid, and if afterwards boiled in an open vessel, 
 gives off nearly the whole of its acetic acid, the alumina nevertheless remaining in 
 solution^ This solution is coagulated by mineral acids and by most vegetable acids, 
 by alkalis, and by decoctions of dye-woods. The alumina contained in it is, however, 
 no longer capable of acting as a mordant, Its coagulum with dye-woods has the 
 
160 ALUMO-CALCITE ALUM- SLATE. 
 
 colour of tlie infusion, but is translucent and totally different from the dense opaque 
 lakes which ordinary alumina forms with the same colouring matters. On evapora- 
 ting the solution to dryness at 100 C. the alumina remains in the form of dihy- 
 drate, retaining only a trace of acetic acid. In this state, it is insoluble in the stronger 
 acids, but soluble in acetic acid, provided it has not been previously coagulated in the 
 manner just mentioned. Boiling potash converts it into the trihydrate (Walter 
 Crum, Chem. Soc. Qu. J. vi. 225). The dihydrate is said to occur native at Beaux 
 (B erthier, Schw. J. xxxiv. 154). Hydrargyllite, a mineral occurring in regular six-sided 
 prisms is also a hydrate of aluminium, but its exact composition is not known. 
 (G. Eose, Pogg. Ann. xlviii. 564; 1. 656.) 
 
 Aluminates. The hydrogen in trihydrate of aluminium, maybe replaced by 
 an equivalent quantity of various metals ; such compounds are called aluminates. Ac- 
 cording to Fremy, a solution of alumina in potash slowly evaporated [out of contact 
 of air ? ] deposits granular crystals of aluminate of potassium, APKO 8 , or Al'O 3 , K' 2 0. 
 Similar compounds occur native; thus Spinellia an aluminate of magnesium, Al-MgO 2 ; 
 Gahnite, an aluminate of zinc, Al 2 Zn0 2 . 
 
 Oxygen-Salts of Aluminium. The general characters of these salts have already 
 been described (p. 154). The most important of them are the sulphate AWSO 4 3 , 
 with its double sulphates, especially common alum, the sulphate of aluminium and 
 potassium, and the silicates and double silicates. [For the detailed descriptions of 
 these salts, see the several Acids.] 
 
 Phosphide of Aluminium.- -Obtained by heating pulverulent aluminium to red- 
 ness in phosphorus vapour. It is a dark grey mass, which acquires metallic lustre by 
 burnishing, and is decomposed by water, with evolution of non-spontaneously in- 
 flammable phosphoretted hydrogen. ( W 6 h 1 e r. ) 
 
 Sillcide of Aluminium. Aluminium combines readily, and in all proportions, 
 with silicon. When strongly heated in contact with any silicious substances, such as 
 glass or porcelain, it reduces the silicon and unites with it. Nevertheless aluminium 
 may be fused in glass or earthen vessels, without undergoing the slightest alteration, 
 provided no flux be used, because it does not then come into intimate contact with the 
 substance of the vessel ; but the addition of a flux produces instant decomposition. 
 The properties of the compound vary with the proportion of silicon. An alloy con- 
 taining 10'3 per cent, of silicon, called cast aluminium (fonte d' aluminium} is grey 
 and very brittle. A compound containing 70 per cent, silicon, still exhibits metallic 
 properties. All the compounds of aluminium and silicon are much more easily 
 altered by exposure to the air, or by the action of ,ids and alkalies, than either pure 
 aluminium or pure silicon. 
 
 Selenide of Aluminium, Al 4 Se 3 , or APSe* Produced with incandescence when 
 aluminium is heated in selenium vapour. It is a black powder, which acquires a 
 dark metallic lustre by burnishing, and is readily decomposed by water or by a moist 
 atmosphere, with formation of alumina and hydroseleuic acid. 
 
 Sulphide of Aluminium, A1 4 S 3 , or APS*. Sulphur may be distilled over alu- 
 minium without combining with it ; but when thrown upon the red-hot metal, it is ab- 
 sorbed with vivid incandescence (W 6 h le r). The sulphide may be prepared by passing 
 the vapour of disulphide of carbon over red-hot alumina. It is fusible, decomposes 
 water at ordinary temperatures, yielding hydrate of aluminium and hydrosulphuric acid, 
 and thus perhaps contributes to the formation of natural sulphur springs. (Fremy.) 
 AXiTTXtXO-CAXiCXTX:. A mineral from Erbenstock, in the Saxon Harz, having 
 the appearance of opal. Specific gravity 2'1 to 2'2, scarcely harder than mica. Con- 
 tains, according to Kersten's analysis, 6'25 per cent, lime, 2'23 alumina, and 40 
 water. It is probably a mere residue of decomposition. 
 
 AI.Tnvi-E.A.R.TH. A massive variety of aluminous schist, found in the neighbour- 
 hood of tertiary lignites, as in several parts of the valley of the Oder, on the Khine, 
 in Picardy, and other localities. It has not a distinct slaty structure, but is a soft, 
 friable, usually dark brown mass. 
 
 AliUlVI-SIaATS. A clay slate, containing bitumen and sulphide of iron, gene- 
 rally found in the transition-strata, but sometimes in more recent formations. It is 
 found in the north of England and in Scotland, in Scandinavia, in the Harz, in the 
 Ural, the Vosges, the lower Rhine, and other localities. There are two varieties of ft, 
 viz. 1. Common. This mineral occurs both massive and in insulated balls of a greyish- 
 black colour, dull lustre, straight slaty fracture, tubular fragments, streak coloured like 
 itself. Though soft, it is not very brittle. Effloresces, acquiring the taste of alum. 
 
 2. Glossy Alum-slate. A massive mineral of a bluish-black colour. The rents dis- 
 play a variety of lively purple tints. It has a semi-metallic lustre in the fracture, 
 
ALUNITE AMARINE. 161 
 
 which is straight, slaty, or undulating. There is a soft variety of it, approaching in 
 appearance to slate clay. By exposure to air its thickness is prodigiously augmented 
 by the formation of a saline effloresence, which separates its thinnest plates. These 
 afterwards exfoliate in brittle sections, causing entire disintegration. 
 
 ALUNITE, or AliUXVI-STOWE. A basic sulphate of aluminium and potas- 
 sium, A1 2 K.2S0 4 + 3A1 2 H 3 3 or A ^J j 4S0 3 + 3(A1 4 3 .3H 2 0), found chiefly in vol- 
 canic districts, viz. at Tolfa, near Civita Vecchia, at Solfatara, near Naples, at Puy do 
 Garcey, in Auvergne, and other localities. Used for the preparation of Eoman alum. 
 
 It is either massive or crystallised ; the former is usually greyish white, and some- 
 times red. It is translucent', easily frangible, scratches calcareous spar, but is scratched 
 by fluor spar. The crystals are generally situated in the cavities of the massive sub- 
 stance, they are small, shining, sometimes externally brownish, their form is an obtuse 
 rhomboid, variously modified. The crystals have the composition above given : the 
 massive variety contains in addition a considerable quantity of silica. 
 AXiUrffOGCHT. Native sulphate of aluminium. (See SULPHATES.) 
 AXVIAXiGAXVl. A combination of mercury with another metal. (See MERCURY.) 
 AftlAIiGAIlXATXON'. The process of extracting gold and silver from their ores 
 by dissolving them out with mercury. (See GOLD and SILVER.) 
 
 AlMAXiXC ACID (from a/u.a\6s, soft, on account of its feeble acid reaction.) A 
 product of the decomposition of caffeine by chlorine (see CAFFEINE), discovered by 
 Eochleder. Its composition is that of alloxantin, having the whole of its hydrogen 
 replaced by methyl : C 4 (CH 3 )*N 4 7 + H 2 0. 
 
 "It forms transparent colourless crystals, which do not give off their water at 100 C. 
 At a higher temperature, it melts and volatilises, leaving scarcely a trace of charcoal, 
 but giving off ammonia, and yielding an oil and crystallised body. It slightly reddens 
 litmus, and produces red stains on the skin, imparting to it an unpleasant odour, like 
 alloxantin. It reduces silver-salts like alloxantin. Nitric acid converts it into a crys- 
 talline substance. When exposed to vapour of ammonia, it gradually assumes a deep 
 violet colour, and forms a compound which dissolves in water with the colour of 
 murexide : the solution yields a crystalline body, to which Eochleder gives the name 
 murexoin. With baryta, potash, and soda, it forms compounds of a deep violet 
 colour. 
 
 AMARTXTXHTE. An organic base obtained by Letellier from the fly agaric (Agari- 
 cus miiscarius, or Amanita muscaria), and from Agaricus bulbosus, and supposed by him 
 to be the poisonous principle of these agarics. According to Apaiger and Wiggers, on 
 the other hand, the fly agaric contains a peculiar acid (muscaric acid), as well as a 
 base, and it is to the acid that the poisonous action is due. (Handw. d. Chem. 2 te Aufl. 
 i. 663.) 
 
 AXVCA&IXJX:. C 21 H' 8 N 2 . Benzoline, 'Pikramin^Hydrureffazobenzoiline. (Laurent, 
 Ann. Ch. Phys. [3] i. 306; Fowrnes, Ann. Ch. Pharm. liv. 363; Gossmann, Ann. 
 Ch. Pharm. xciii. 329; Gm. xii. 193.) 
 
 This compound was discovered simultaneously by Laurent and by Fownes. It is 
 isomeric with hydrobenzamide, from which it is generally prepared. 1. When hydro- 
 benzamide is heated for three or four hours to 120 130 C., the vitreous mass, when 
 cool, dissolved in boiling alcohol, and excess of hydrochloric acid added, white crystals 
 of hydrochlorate of amarine separate out (Bertagnini). 2. Hydrobenzamide is 
 boiled for some hours with caustic potash, the resulting resin dissolved in dilute sul- 
 phuric acid, the solution precipitated by ammonia, and the precipitate washed with 
 water and crystallised from hot alcohol (Fownes). 3. A solution of bitter-almond 
 oil in alcohol, when saturated with gaseous ammonia, solidifies in 24 48 hours into 
 a crystalline mass. This is boiled with water, and saturated while hot with hydro- 
 chloric acid, when an oily substance separates out, together with crystals of a peculiar 
 acid (see BENZIMIC ACID). The hot solution is decanted, and the residue again 
 extracted with boiling water, until all the hydrochlorate of amarine is dissolved out. 
 The solution is precipitated by ammonia ; and the precipitate is washed, dissolved in 
 boiling alcohol, mixed with hydrochloric acid, and reprecipitated by ammonia : pure 
 amarine then crystallises out (Laurent). 4. When the dry compound of bitter- 
 almond oil and acid sulphite of ammonium is heated in a large retort to 180 200 
 with 3 or 4 times its volume of slaked lime, amarine and lophine distil over. The 
 former, which collects partly in the receiver, partly in the lower part of the neck of 
 the retort, is dissolved in alcohol, and purified as in the former process. (Gossmann.) 
 
 Amarine crystallises from alcohol in shining six-sided prisms. It melts at 100C. 
 and solidifies to a vitreous mass on cooling : when heated more strongly, it volatilises 
 
 VOL. I. M 
 
162 AMARONE. 
 
 almost completely, ammonia being evolved : an oil smelling like benzol distils over, and 
 a sublimate collects in the neck of the retort, which Fownes calls pyrobcnzoline, and 
 which, according to Laurent, is identical with lophine. Amarine is inodorous, taste- 
 less at first, but afterwards slightly bitter. It is insoluble in water, soluble in al- 
 cohol and ether ; the alcoholic solution is strongly alkaline. Amarine becomes strongly 
 electrical by friction. Unlike its isomer, hydrobenzamide, it exerts a poisonous action 
 on animals. 
 
 Amarine is readily attacked by bromine, hydrobromate of amarine being formed 
 together with a resinous mass. When it is boiled with a mixture of sulphuric and 
 chromic acids and water, a brisk action takes place, and benzoic acid is abundantly 
 formed. Nitric acid acts similarly, but less violently. Fused potash does not attack 
 it, save at a very strong heat. 
 
 Amarine-salts are formed by the direct combination of amarine with acids. With 
 the exception of the acetate, they are all but slightly soluble. The hydrochlorate, 
 C 21 H 18 N 2 ,HC1, crystallises in small shining needles, which effloresce in vacuo, or when 
 heated to 100. When hydrochloric acid is poured upon amarine, a colourless oil in 
 formed, which gradually solidifies on drying, and may be drawn into threads when 
 heated. It distils without decomposition, passing over as an oil which solidifies to a 
 transparent mass. It is soluble in alcohol and ether. The chloroplatinate separates in 
 yellow needles, when boiling alcoholic solutions of the hydrochlorate and of dichloride 
 of platinum are mixed together. Fownes found in it 19 '8 per cent, platinum; the 
 formula PtCl s .C 21 H 19 N 2 requires 19-58 per cent. The sulphate crystallises from an acid 
 solution in small colourless prisms resembling oxalic acid. The nitrate is obtained 
 by treating amarine with hot dilute nitric acid ; a soft, amorphous mass is produced, 
 which dissolves in boiling water, and on cooling deposits small crystals, which remain 
 unaltered in vacuo. The acetate is very soluble, and yields on evaporation a gummy 
 non-crystalline mass. 
 
 Diethylamarine, C 21 (C 2 H 5 ) 2 H 16 N 2 . Amarine heated with iodide of ethyl, 
 yields a crystalline salt, which is the hydriodate of this base. The base itself is ob- 
 tained by distilling the hydriodate with potash. It crystallises readily in oblique 
 rhombic prisms, is nearly insoluble in water, but dissolves readily in alcohol and ether. 
 It melts between 110 and 115 C. but does not solidify again till cooled down to 
 70. At a stronger heat it decomposes. The hydrochlorate crystallises in oblique 
 rhombic prisms. The platinum-salt is a yellow powder, insoluble in water and in 
 ether, but soluble in alcohol, from which it crystallises in small prisms. (B or o dine, 
 Ann. Ch. Pharm. ex. 78.) 
 
 Diethylamarine treated with iodide of ethyl yields the hydriodate of another crystal- 
 line base, probably triethylamarine, which however has not yet been analysed, and 
 this base again treated witli iodide of ethyl, yields a third crystalline base. (Borodine.) 
 
 Trinitramarine, C 21 H 15 (NO 2 ) 3 N 2 (Bertagnini, Ann. Ch. Pharm. Ixxix. 275). 
 This compound is formed from trinitrohydrobenzamide, with which it is isomeric, just 
 as amarine is from hydrobenzamide. Triuitrohydrobenz amide is boiled with 1 vol. 
 caustic potash of 46 Baum6, and 50 vols, water; the resulting brown resinous 
 mass (which becomes brittle on cooling) is dissolved in hot alcohol ; a little ether 
 added ; and the solution is precipitated by hydrochloric acid. The hydrochlorate is 
 redissolved in alcohol, alcoholic ammonia added to the solution, and the precipitated 
 trinitramarine is washed with water, and recrystallised from alcohol Trinitramarine 
 is also obtained by heating trinitrohydrobenzamide in an oil-bath to 125 130 C. 
 
 It crystallises slowly from its alcoholic solution in white hard nodules. It melts in 
 boiling water, and dissolves slightly, forming an alkaline solution. It is soluble 
 in boiling alcohol or ether, most readily in a mixture of the two. A hot saturated 
 solution deposits it on cooling as an amorphous powder. 
 
 Its salts are but slightly soluble in water. The hydrochlorate separates in small 
 shining needles when hydrochloric acid is added to an alcoholic solution of trinitra- 
 marine ; it is nearly insoluble in cold, slightly soluble in boiling alcohol. The nitrate 
 crystallises in needles from boiling alcohol. An alcoholic solution of trinitramarine 
 forms with dichloride of platinum; small, yellow, heavy nodules insoluble in alcohol ; 
 and with mercuric chloride, a somewhat crystalline precipitate. F. T. C. 
 
 A7V5AROWTE. C 16 H"N (Laurent, Rev. Scient. xviii. 207, &c). A compound 
 formed by the dry distillation of azobenzoyl, benzoylazotide, or hydrobenzamide. The 
 sublimate obtained by heating benzoylazotide is washed with ether, and then freed 
 from lophine by boiling in alcohol containing hydrochloric acid ; the residue is washed 
 with alcohol, dried, crystallised from boiling rock-oil, and washed with ether. It forms 
 small, colourl ss, inodorous needles, which melt at 233 C., and solidify to a radiated 
 mass on cooling. It is insoluble in water, slightly soluble in alcohol, more readily 
 in ether. It dissolves in cold sulphuric acid, with a fine blood-red colour, which dis- 
 
AMARYL AMBER 163 
 
 appears on addition of water, the araarone separating out. It dissolves sparingly in 
 hot nitric acid, and crystallises unchanged on cooling. It is not decomposed by boiling 
 with alcoholic potash. F. T. C. 
 
 A name given by Laurent to a substance which he afterwards found 
 to be impure nitrate of lophine. 
 
 A1VTARYTHRIN. Syn. with ERYTHRIN-BITTER or PICBO-ERYTHRIN. 
 AMASATiar. Syn. with ISAMIDE. 
 A1KAUSXTE. Compact FELSPAB. 
 
 AMAZOlff-STOM'E. A variety of orthoclase, coloured green by copper. It is 
 found chiefly in the shores of Lake Ilmen in Eussia, also in Norway. It is used for 
 making trinkets. 
 
 AIVXBER. Sziccin, Elecfrum, Ambra flava, Bernstein, Agtstein, gelbes Erdharz. - 
 A hard brittle tasteless substance, sometimes perfectly transparent, but mostly semi- 
 transparent or opaque, and of a glassy surface ; it is found of all colours but chiefly 
 yellow or orange, and often contains leaves or insects. Its specific gravity varies from 
 1-065 to 1 - 070 ; hardness 2 to 2*5 ; slightly brittle; fracture conchoidal. It is susceptible 
 of a fine polish, and becomes electric by friction : hence the word electricity (from 
 ij\Krpov, amber). When rubbed or heated, it emits a peculiar smell. It is insoluble 
 in water and alcohol, though the latter, when highly rectified, extracts a reddish colour 
 from it. It is soluble in sulphuric acid, to which it imparts a reddish purple colour, 
 but is reprecipitated on addition of water. No other acid dissolves it, nor is it soluble 
 in essential or expressed oils without decomposition ; but pure alkalis dissolve it. 
 
 According to Berzelius, amber contains a volatile oil, succinic acid, and two resins 
 soluble in alcohol and ether. According to Schroetter and Forchammer, amber when 
 deprived by ether of all its soluble constituents, possesses the composition of camphor 
 viz. C'H I6 0. 
 
 The dry distillation of amber presents three distinct phases, characterised by the 
 nature of the products. When submitted to the action of heat, amber softens, fuses, 
 intumesces considerably, and gives off succinic acid, water, oil, and a combustible 
 gas. If now the residue (Colophony of Amber) be more strongly heated, a colourless 
 oil passes over. Lastly, when the residue is completely charred, and the heat is raised 
 till the glass nearly fuses, a yellow substance sublimes of the consistence of wax. 
 
 The oil thus produced is a mixture of several hydrocarbons. The more volatile portion 
 wnich passes over between 110 and 260- C., is decomposed in the cold by sulphuric acid, 
 and coloured blue by hydrochloric acid, and by chlorine ; the less volatile portion produced 
 by a heat approaching redness, begins to boil at 140, and then rises to 300 ; sulphu- 
 ric and hydrochloric acid and chlorine do not alter it. According toPelletier and 
 Walter (Ann. Ch. Phys. [3] ix. 89), these oils present the composition of oil of 
 turpentine, containing 88'7 percent, of carbon, and 11'3 of hydrogen. 
 
 The crude mixture of the two oils is used in pharmacy under the name of oil of 
 amber, being in fact one of the constituents of Eau de Luce, a preparation sometimes 
 used as a remedy for the bites of venomous animals, and consisting of 1 part of oil 
 of amber, 24 of alcohol, and 96 of caustic ammonia. 
 
 The wax-like solid which passes over in the dry distillation of amber is a mixture 
 of oil, yellow matter, a white crystalline substance, and a brown bituminous substance ; 
 these bodies are separated by treatment with ether and alcohol. The yellow matter 
 appears to be identical with chrysene (C 94-4, H 5*8). It is scarcely soluble in 
 boiling alcohol and ether, is pulverulent rather than crystalline, and requires for 
 fusion a temperature of 240 C. 
 
 The white matter (succisterene) is tasteless and inodorous, it is scarcely soluble in 
 cold alcohol, but little soluble in ether, but more soluble than the yellow matter ; it 
 melts between 160 and 162, and distils above 300. Nitric acid resinises it 
 in the cold. It contains, according to Pelletier and Walter, 95'6 per cent, of carbon 
 and 5-6 of hydrogen. 
 
 When amber is treated with fuming nitric acid, a resin is formed (artificial musk) 
 which is soluble in an excess of nitric acid, and contains C 15 H 16 N 2 2 . 
 
 When powdered amber is distilled with a strong solution of potash, a watery liquid 
 passes over, together with a white substance which exhibits all the properties of com- 
 mon camphor. 
 
 Amber occurs plentifully in ^egular veins in some parts of Prussia, especially between 
 Palmnicken and Grosz-Hubenicken. In East and West Prussia there is scarcely a 
 village where it has not been found, and thence it extends into Mecklenburg and HoJ- 
 stein and in fact along the whole Baltic plain. It has likewise been found in southern 
 Germany, in France, Italy, Spain, Sweden and Norway ; also on the shores of the 
 
 M 2 
 
164 AMBERGRIS AMBLYGONITE. 
 
 Caspian, in Siberia, Kamtschatka, China, Hindoostan, Madagascar, North America 
 and Greenland. In Britain it is thrown out by the sea on the shores of Norfolk, Suffolk 
 and Essex, and has also been found in the sands at Kensington. In the Royal Cabinet 
 at Berlin there is a mass of 18 Ibs. weight, supposed to be the largest ever found. 
 
 Haiiy has pointed out the following characters by which amber may be distin- 
 guished from mellite and copal, the bodies which most closely resemble it. Me] lite 
 is infusible by heat ; a bit of copal heated at the end of a knife takes fire, melting 
 into drops, which flatten as they fall; whereas amber burns with spitting and frothing, 
 and when its liquefied particles drop, they rebound from the plane which receives them. 
 
 Various frauds are practised with this substance. Neumann states as the common 
 practices of workmen the two following : The one consists in surrounding the amber 
 with sand in an iron pot, and cementing it with a gradual fire for forty hours, some 
 small pieces placed near the sides of the vessel being occasionally taken out for judging 
 of the effect of the operation. The second method, which he says is that most generally 
 practiced, is to digest and boil the amber about twenty hours with rapeseed oil, by 
 which it is rendered both clear and hard. 
 
 The chemical properties and mode of occurrence of amber leave no doubt of its 
 being the produce of extinct coniferse. It has been found encrusting or penetrating 
 fossil wood exactly like resin at the present day, and enclosing the cones and leaves of 
 the trees. Numerous insects, the inhabitants of these ancient forests have been em- 
 balmed in it. To the tree which principally produced it, Goppert gives the name of 
 Pinitcs sitccinifcr, but there was probably more than one species. Amber is often 
 stated to occur in the brown coal beds of Northern Germany, but Goppert states that 
 he knows of no instance of this, the substance found in those beds being retinite. 
 (Handw. d. Chem. 2te Aufl. ii. 972; Dana, ii. 466; Gerh. iv. 394). 
 
 AMBERGRIS. (Ambra, Ambra grisea), is found in the sea, near the coasts of 
 various tropical countries ; and has also been taken out of the intestines of the sperma- 
 ceti whale (Physeter macrocephalus). As it has not been found in any whales but 
 such as are dead or sick, its production is generally supposed to be owing to disease, 
 though some have a little too positively affirmed it to be the cause of the morbid 
 affection. As no large piece has ever been found without a greater or smaller quantity of 
 the beaks of the sepio octopodia, the common food of the spermaceti whale, interspersed 
 throughout its substance, there can be little doubt of its originating in the intestines 
 -of the whale : for if it were merely occasionally swallowed by the animal, and then 
 caused disease, it would much more frequently be without these bodies, when it is 
 met with floating in the sea, or thrown upon the shore. 
 
 Ambergris is found of various sizes, generally in small fragments, but sometimes so 
 large as to weigh near two hundred pounds. When taken from the whale, it is not so 
 hard as it afterwards becomes on exposure to the air. Its specific gravity ranges from 
 0-780 to 0'926. If good, it adheres like wax to the edge of a knife with which it is scraped, 
 retains the impression of the teeth or nails, and emits a fat odoriferous liquid on being 
 penetrated with a hot needle. It is generally brittle ; but, on rubbing it with the nail, 
 it, becomes smooth, like hard soap. Its colour is either white, black, ash-coloured, 
 yellow, or blackish ; or it is variegated, namely, grey with black specks, or grey with 
 yellow specks. Its smell is peculiar, and not easy to be counterfeited. At 62-2 C. 
 it melts, and at 100 C. is volatilised in the form of a white vapour; on a red-hot 
 coal it burns, and is entirely dissipated. Water has no action on it ; acids, except 
 nitric acid, act feebly on it ; alkalis combine with it, and form a soap ; ether and the 
 volatile oils dissolve it ; so do the fixed oils, and also ammonia, when assisted by heat ; 
 alcohol dissolves a portion of it. 
 
 The principal constituent of ambergris is ambrein (q. v.) Succinic and benzoic 
 acids are said to be sometimes found among the products of its destructive distillation. 
 Its inorganic constituents are carbonate and phosphate of calcium, with traces of ferric 
 oxide and alkaline chlorides. 
 
 An alcoholic solution of ambergris, added in minute quantity to lavender water, 
 tooth powder, hair powder, wash balls, &c. communicates its peculiar fragrance. Its 
 retail price being in London a guinea per oz. leads to many adulterations. These 
 consist of various mixtures of benzoin, labdanum, meal, &c. scented with musk. The 
 greasy appearance and smell which heated ambergris exhibits, afford good criteria, 
 joined to its solubility in hot ether and alcohol. 
 
 It has occasionally been employed in medicine, but its use is now confined to the 
 perfumer. Swediaur took thirty grains of it without perceiving any sensible effect. U. 
 
 AMBIiYGOKTITE. A greenish-coloured mineral of different pale shades, marked 
 on the surface with reddish and yellowish-brown spots. It occurs massive and crystallised 
 in oblique four-sided prisms. Lustre vitreous ; cleavage parallel to the sides of an 
 oblique four-sided prism of 106 10' and 77 50' ; fracture uneven ; fragments rhom- 
 boidal; translucent; hardness as felspar; brittle; specific gravity 3'0: intumesces 
 
AMIC ACIDS. 165 
 
 with the blowpipe, and fuses with a reddish-yellow phosphorescence into a white 
 enamel. It occurs in granite, with green topaz and tourmaline, at Chursdorf and 
 Arnsdorf, near Pinig, in Saxony. A specimen from Arsndorf analysed by Kammelsberg 
 gave 47-15 phosphoric anhydride, 88'43 alumina, 7'03 lithia, 3'29 soda, 0'43 potash. 
 and 8' 11 fluorine, agreeing very nearly with the formula: 
 
 (5A1 4 3 .3P 2 5 + 5M 2 0.3P 2 5 ) + 2 (A1 2 F 3 + MR) 
 (Handwork d. Chem. 2te Aufl. i. 665 ; Dana, ii. 409.) 
 
 By digesting ambergris in hot alcohol, specific gravity 0'827, the 
 peculiar substance, called ambrem by Pelletier and Caventou, is obtained. The alcohol, 
 on cooling, deposits the ambrem in very bulky and irregular crystals which still retain 
 a very considerable portion of alcohol. Thus obtained, it has the following properties : 
 It is of a brilliant white colour, has an agreeable odour, of which it is deprived by 
 repeated solution and crystallisation. It is destitute of taste, and does not act on 
 vegetable blues. It is insoluble in water, but dissolves readily in alcohol and ether ; 
 and in much greater quantity in these liquids when hot than when cold. It melts at 
 30 C. (86 G F.) softening at 25 C. When heated above 100 C., it is partly volatilised 
 and decomposed, giving off a white smoke. It does not seem capable of combining 
 with an alkali, or of being saponified. When heated with nitric acid, it becomes 
 green and then yellow, eliminates nitrous gas, and is converted into an acid, which 
 has been called ambreic acid. This acid is yellowish white, has a peculiar odour, 
 reddens vegetable blues, does not melt at 100 C., and does not evolve ammonia 
 when decomposed at higher temperatures. It is soluble in alcohol and ether ; but 
 slightly so in water. Ambreate of potassium forms yellow precipitates with chloride 
 of calcium, protosulphate of iron, nitrate of silver, acetate of lead, corrosive sublimate, 
 protochloride of tin and chloride of gold. ' (J. Pharm. v. 49.) 
 
 Ambrein is perhaps impure cholesterin, -which substance it greatly resembles in its 
 properties. Pelletier (Ann. Ch. Pharm. vi. 24) found it to contain 83-3 p. c. C, 
 13-3 H, and 3'32 0, which is nearly the composition of cholesterin: if this be so, 
 ambreic acid is probably identical with cholesteric acid. 
 
 AltXETH AWES. A name applied to the ethers of the amic acids, e. g. oxamethane 
 to oxamate of ethyl. (See AMIC ACIDS.) 
 
 AIWETHYST. The amethyst is a gem of a violet colour, and great brilliancy, 
 said to be as hard as the ruby or sapphire, from which it differs only in colour. This 
 is called the oriental amethyst, and is very rare. When it inclines to the purple or 
 rose colour, it is more esteemed than when it is nearer to the blue. These amethysts 
 have the same figure, hardness, specific gravity, and other qualities, as the best sap- 
 phires or rubies, and come from the same places, particularly from Persia, Arabia, 
 Armenia, and the West Indies. The occidental amethysts are merely coloured crystals 
 of quartz. U. (See QUARTZ and SAPPHIRE.) 
 
 AnxiANTHOID. A variety of Hornblende (q. v.) 
 AMIANTHUS. Mountain flax. (See ASBESTOS.) 
 
 AMIC ACIDS. By this name are designated a class of nitrogenised acids, which 
 differ from the acid ammonium-salts of polybasic acids by the elements of one or more 
 atoms of water ; and which, under certain circumstances, are capable of taking up the 
 elements of water, and regenerating ammonia and the original non-nitrogenised poly- 
 basic acid. They bear a considerable resemblance to amides in their modes both of 
 formation and of decomposition : but they differ from these bodies in possessing 
 invariable and decided acid properties, and in not deriving from the type NH 3 . 
 
 With regard to their constitution, amic acids are best regarded as deriving from 
 the double type NH S ,H 2 0. They represent this type in which 2, 3, or 4 atoms of 
 hydrogen are replaced by other radicles, one of which must be the radicle of a polybasic 
 acid : and they may be divided into 3 classes, according as 2, 3, or 4 atoms of hydrogen 
 are so replaced. In class 1, therefore, it is obvious that 2 atoms of hydrogen in 
 the type must be replaced by 1 diatomic acid radicle ; in class 2, three atoms of 
 hydrogen may be replaced by 1 triatomic, or by 1 diatomic and 1 monatomic acid radicle ; 
 and so on. No amic acid is formed by the substitution of an acid radicle of less than 
 2 atoms of hydrogen in the type : if 1 atom of hydrogen in NH 3 ,H 2 be replaced by 
 the radicle of a monobasic acid, the only result is the formation of the ammonium-salt 
 of that acid, e. g. : 
 
 NH 3 (C 2 H 3 0)HO = C 2 H 3 O.NH*.0 
 
 Acetyl. Acetate of 
 
 ammonium 
 
166 AMIC ACIDS. 
 
 Neither can an amic acid be formed by replacing 2 atoms hydrogen in the type by 
 2 monatomic acid radicles ; for when benzoic anhydride is treated with ammonia, the 
 2 atoms of benzoyl, each equivalent to H, do not remain combined, forming an amic acid, 
 but separate, forming 2 distinct compounds, benzamide and benzoate of ammonium : 
 
 (C'H 5 0) 2 .0 + 2NH 3 = N.C'H'O.H 2 + C'H 5 O.NH 4 .0 
 
 Benzoic anhyd. Benzamide. Benzoate of anim. 
 
 But when a dibasic anhydride is treated with ammonia, the acid radicle, equivalent to 
 H' 2 , being indivisible, is incapable of separating so as to form two distinct compounds ; 
 so that a single compound is necessarily formed, the ammonium-salt of an amic acid : 
 
 S0 2 .0 + 2NH 3 = 
 
 Sulphuric Sulphamate of 
 
 anhyd. amm. 
 
 Hence it follows that a monobasic acid is incapable of forming an amic acid : in fact 
 the possession of this property is perhaps one of the most distinguishing characteristics 
 of polybasic acids. 
 
 We now proceed to describe the modes of formation, properties, and reactions of 
 amic acids, dividing them into 3 classes, according as 2, 3, or 4 atoms of hydrogen are 
 replaced in the type. 
 
 Class 1. They represent the type NHHH HHO in which 2 atoms of hydrogen are 
 replaced by one diatomic acid radicle : 
 
 //* tt 
 
 Sulphamic acid ....... NH.H.S0 2 .H.O 
 
 Carbamicacid ....... NHJLCOH.O 
 
 Oxamic acid 
 
 Succimamic acid ....... NH.H.C 4 H 4 2 .H.O 
 
 They are formed 1. By action of heat on the acid ammonium-salt of a dibasic acid : 
 
 C 2 2 .(NH 4 )H.0 2 - H 2 
 
 Acid oxalate of amm. Oxamic acid. 
 
 In some cases, e. g. comenamic acid, NH 2 .C 6 H 2 3 .H.O, prolonged boiling of the am- 
 monium-salt with water is sufficient. 
 
 2. By action of ammonia on anhydrides : 
 
 C 10 H 14 2 .0 + NH 3 = NH 2 .C 10 H 14 2 .H.O 
 
 Camphoric Camphoramic acid. 
 
 anhyd. 
 
 The best mode is to dissolve the anhydride in absolute alcohol, and to lead dry 
 ammonia into the solution. The reaction takes place with 2 atoms of ammonia, an amate 
 of ammonium being formed. 
 
 3. By action of ammonia on acid salts of organic radicles : 
 
 C 7 H 4 0.(CH 3 )H.0 2 + NH 3 = NH 2 Tc ; H 4 aH.O + CH 3 .H.O 
 
 Acid salicylate of methyl. Salicylamic acid. Methylic 
 
 (Methyl -salicylic acid.) alcohol. 
 
 4. By action of aqueous ammonia on ethers of dibasic acids. (G-erhardt, Chim. 
 org. iv. p. 668.) 
 
 C 10 H 16 2 .(C 2 H 5 ) 2 .0 2 + NH 3 + H 2 = NHWHJI.O + 2/C 2 H 5 .H.O\ 
 
 Sebamicacid. V Alcohol. ) 
 
 6. Imides, boiled with dilute ammonia, take up H 2 0, and form amic acids : some 
 alkalamides exhibit the same reaction : 
 
 N.C 4 H 4 2 .H + H 2 = NHTc 4 H 4 2 5.0 
 
 Succinimide. Succinamic acid. 
 
AMIC ACIDS. 167 
 
 N.C 4 H 4 2 .Ag. + H'O = NH 2 .C 4 H 4 2 .Ag.O 
 
 Argento-succini- Succinamate of silver, 
 
 mide. 
 
 6. Some primary diamides, boiled with mineral acids or alkalis, take up H 8 0, and 
 form amic acids, or amates of ammonium : 
 
 N 2 .C 4 H 4 8 .H 4 + H 2 = NH 2 jC 4 H 4 6tH.O + NH 3 
 
 Malamide. Malamic acid. 
 
 (A&paragine.) (Aspartic acid.) 
 
 7. Some amic acids are formed by the action of hydrosulphuric acid on nitro-conju- 
 gated acids : 
 
 C 7 H 4 (N0 2 )O.H.O + 3H 8 S = NH?c5 4 oS.O + 2H 2 + 3S 
 
 Nitrobenzoic acid. Oxybenzamic acid. 
 
 The acid thus formed is commonly called benzamic acid ; an impossible name, as 
 benzoic acid is monobasic. We regard it as the amic acid of oxybenzoic acid, 
 C 7 H 4 O.H 2 .0 2 , a diatomic acid, although it does not form acid salts. Strecker regards 
 this amic acid as phenylcarbamic acid, NH.C 6 H 5 .CO.H.O. 
 
 Class 2. They represent the type NHHH HHO in which 3 atoms hydrogen of are re- 
 placed ; (a) by 1 triatomic acid radicle, (b) by 1 diatomic and 1 monatomic acid radicle, 
 (c) by 1 diatomic acid, and 1 monatomic basic radicle. 
 
 a. 3H are replaced by 1 triatomic acid radicle : 
 
 /// // 
 
 Phosphamic acid, NH.PO.H.O, formed by the action of ammonia on phosphoric 
 anhydride : 
 
 P 2 5 + 2NH 3 = 2(N.HPO.H.O) + H 2 0. 
 
 b. 3H are replaced by 1 diatomic and 1 monatomic acid-radicle : 
 
 Benzoylsalicylamic acid .... NH.C 7 H 5 O.C 7 H 4 O.H.O 
 
 Sulphophenyl-succinamic acid . . . NH.C 6 H 5 S0 2 .C 4 H 4 2 .H.O. 
 
 Obtained by boiling certain tertiary amides with aqueous ammonia (G-erhardt and 
 Chiozza): 
 
 KC 6 H 5 S0 2 .C 4 H 4 2 + NH 4 .H.O = 
 
 Sulphophenyl-succina- Sulphophenyl-succinamate of amm. 
 
 mide. 
 
 c. 3H are replaced by 1 basic monatomic and 1 acid diatomic radicle : 
 Ethyloxamic acid 
 
 Phenylsulphamic (sulphaniHc) acid . . . NH.C 6 H 5 .SO 2 .H.O 
 
 Phenylsuccinamic (succinanilic) acid . . . NH.C 6 H 5 .C 4 H 4 2 .H.O. 
 These compounds (which may be called alJcalamic acids) are obtained by the sarm 
 reactions that serve for the formation of acids of class 1, a primary amine being sub 
 stituted for ammonia: 
 
 1. By heating the acid salts of organic alkalis : 
 
 - H 2 
 
 2. By action of primary amines on dibasic anhydrides : 
 
 Acid oxalate of me- Methyloxamic acid. 
 
 thylium. 
 
 C 5 H 6 2 .0 + N.C 6 H 5 .H 2 
 
 Pyrotartaric Phenylamine. Phenylpyrotartramic acid. 
 anhyd. 
 
 M 4 
 
168 AMIDES. 
 
 3. By heating alkalimides with dilute ammonia : 
 N.C 6 H S .C 4 H 4 3 + H 2 
 
 Phenylmalamide. Phenylmalamic acid. 
 
 Class 3. They represent the type NH 3 ,H 2 in which four atoms of hydrogen are 
 replaced by other radicles, one of which must be a polyatomic acid radicle. The only 
 known members of this class are a few phenyl-compounds : phenylcitramic acid, 
 
 N.C B H S .C 6 H 5 4 .H.O, is an example. 
 
 There are also certain nitrogenised acids, which either exist ready formed in nature, 
 or are products of the decomposition of other compounds, which we may regard as 
 amic acids. Thus glycocoll, C 2 H 5 N0 2 , is the amic acid of glycollic acid,C 2 H 2 O.H 2 .0 2 , 
 and maybe written NH 2 .C 2 H-O.H.O. Hippuric, choleic, and other acids may also be 
 regarded as amic acids ; but their constitution is as yet but imperfectly understood. 
 
 Amic acids are distinct monobasic acids : they form well defined salts, which are 
 generally more soluble than those of the corresponding dibasic acids. They are mostly 
 solid, crystalline, not volatile without decomposition. When heated, many of them 
 lose the elements of 1 atom of water, and are converted into imides: others are decom- 
 posed into a dibasic anhydride and a primary amine. When boiled with mineral acids 
 or alkalis, they mostly take up the elements of 1 atom of water, and regenerate the 
 corresponding dibasic acid, and ammonia or a primary amine : in some cases, the mere 
 boiling of their aqueous solutions suffices for this reaction ; in others, fusion with solid 
 potash is required : 
 
 // // 
 
 H 2 = C 4 H 4 2 .H 2 .0 2 + N.C 6 H 5 .H 2 
 
 Phenylsuccinamic acid. Succinic acid. Phenylamine. 
 
 With nitrous acid, many amic acids regenerate the corresponding dibasic acid, with 
 evolution of nitrogen : 
 
 NHO 2 = C 4 H 4 9 .H 2 .0 2 + N 2 + H 2 0. 
 
 Malamic acid. Malic acid. 
 
 Like all decided acids, amic acids form ethers, i. e. salts of alcohol-radicles. These 
 amic ethers are sometimes called urethancs (or amethanes), the former name having 
 been applied to the earliest discovered, carbamic ether. They are formed by the in- 
 complete action of ammonia on the ethers of dibasic acids : 
 
 C 2 2 .(C 2 H 5 ) 2 .0 2 + NH 3 = HmCWcS'.O + C 2 H 6 .H.O. 
 
 Oxalic ether. Oxamic ether. Alcohol. 
 
 They are isomeric with alkalamic acids. When boiled with water, acids, or alkalis, 
 they are converted into dibasic acids, alcohol, and ammonia : 
 
 NH 2 .C 2 2 .C 2 H 5 .0 + 2H 2 = C 2 2 .H 2 .0* + C 2 H 5 .H.O + NH 8 . 
 
 Oxamic ether. Oxalic acid. Alcohol. 
 
 Excess of ammonia converts them into primary diamides (q. v.} F. T. C. 
 
 Amic Bases. This name may be given to a class of bodies produced by the action 
 of ammonia on the oxides, or chloro- or bromo- hydrates of polyatomic alcohol-radicles, 
 and which are related to the polyatomic alcohols in the same way as the amic acids to 
 th polyatomic acids. Their leading properties may be expressed by representing 
 them as derived from a combination of the types NH 8 and H 2 0. 
 
 The following bodies belonging to this class are already known : 
 
 Anisamine, C 8 HNO 
 
 Dianisamine, C 16 H 19 NO = ^ jj?'0i 
 
 Diglycolamine, C 4 HN0 2 = 
 
 Glyceramine, C 3 H 9 NO = 
 Diglyceramine, C 6 HN0 2 = 
 
 (C%> 
 
 H S N ) 
 2(H 2 0)S 
 
 Triglycolamine, C 6 H 15 N0 3 ~ w ~ 8 ' JQ; t 7P e 3()| 
 
AMIDES. 169 
 
 AMIDES. Ammonia, NHHH, is capable, under certain circumstances, of ex- 
 changing each atom of its hydrogen successively for a metal, or for a compound radicle, 
 acid or basic, thus giving rise to a numerous class of compounds, all deriving from 
 the same type, NHHH. The earliest discovered of these compounds were some of 
 those in which one atom of hydrogen was thus replaced, e. g. NHHK, which was re- 
 garded as a compound of NH 2 (amidogeri) with potassium, NH 2 K, and called amide of 
 potassium, analogous to the cyanide, CNK. In process of time, compounds came to be 
 discovered, deriving from the type NHHH, in which 2 or 3 atoms of hydrogen were 
 replaced by metals or compound radicles, to which the name amide in its original sense 
 of a compound containing amidogen, NH 2 , was plainly inapplicable ; accordingly these 
 compounds were designated by other names, imides, nitriles, &c., the introduction of 
 which has caused considerable confusion, since they in no way indicate the common 
 derivation of all these compounds. 
 
 Of late years attempts have been made, chiefly by Gerhardt, to remedy this confu- 
 sion, by assigning to this numerous class of compounds a rational constitution which 
 shall render evident their common derivation, and a nomenclature by which this con- 
 stitution is at once expressed. These attempts have been attended with considerable 
 success : and the classification adopted in this article is based upon that given by 
 Gerhardt and Chiozza (Ann. Ch. Phys. [3] xlvi.), certain modifications being 
 introduced where greater clearness seems thereby to be attained. 
 
 Since the hydrogen in ammonia is capable of being replaced either by acid- or by base- 
 radicles (simple or compound), the first obvious division of the compounds thus formed 
 is one based upon the nature of the radicle which has been substituted for hydrogen. 
 These compounds thus fall into three great divisions : 
 
 1. Ammonias in which 1 or more atoms of hydrogen are replaced by an acid-radicle. 
 To this division we propose to confine the name of amides. In the case of each in- 
 dividual member of the class, the generic name is preceded by a prefix, which indicates 
 the particular acid radicle or radicles contained in the compound, e.g. acetamide 
 N.C 2 H 3 O.H 2 , diacetamide N.(C 2 H 3 0) 2 H, &c. 
 
 2. Ammonias in which 1 or more atoms of hydrogen are replaced by ias^-radicles. 
 This division we call amines. For examples of the nomenclature of individuals, 
 we may take potassamine, N.K.H 2 , ethylamine, N.C 2 H 5 .H 2 , methylethylamine, 
 N.CH 3 .C 2 H 5 .H, &c. 
 
 3. Ammonias in which 2 or more atoms of hydrogen are replaced by acid- and 
 base-radicles. This division we call alkalamides. Examples are ethylacetamide, 
 N.C 2 H 5 .C 2 H 3 O.H, phenyldibenzamide, N.C 6 H 5 .(C 7 H 5 0) 2 . 
 
 This primary classification enables us to perceive in compounds deriving from fh.> 
 type ammonia, NHHH, the same seriation of properties which was first pointed out 
 by Gerhardt in the compounds deriving from the type oxide, OHH. As in the latter 
 case, we have metallic oxides (bases) occupying the positive extreme, acids the negative 
 extreme, while the middle place is filled up by salts, containing at once an acid- and 
 a base-radicle ; so in the former case, we have amines at the positive extreme, amides 
 at the negative, and alkalamides between the two extremes. 
 
 A further ground for division is furnished by the fact that amides, amines, and 
 alkalamides may derive from 1, 2, or 3 molecules of ammonia, according as they con- 
 tain monatomic, diatomic, or triatomic radicles. Hence we have a further division of 
 amides into 
 
 1 . Monamides (or amides), deriving from 1 mol. ammonia NHHH. 
 
 2. Diamides 2 mols. N 2 H 2 H 2 H 2 . 
 
 3. Triamides 3 mols. N 3 H 3 H 3 H 3 . 
 The same subdivision applies to amines and alkalamides. 
 
 In each of these types, NHHH, N 2 H 2 H 2 H 2 , N S H 8 H S H 3 , one third, two thirds, or the 
 whole of the hydrogen may be replaced by acid- or base-radicles : hence arises a further 
 division of amides, diamides, and triamides into : 
 
 1. Primary, in wh. | of the hydrogen is replaced, NAHH, N 2 A"H 2 H 2 , N 8 A'"H 3 H 3 
 
 2. Secondary, in wh. of the hydrogen is replaced, NA 2 H, N 2 (A") 2 H 2 , N 3 (A"') 2 H 3 . 
 
 3. Tertiary, in wh. the whole of the hydrogen is replaced, NA 8 , N 2 (A") 3 , N 3 (A'") 3 . ' 
 
 The same subdivision applies to amines, and (partially) to alkalamides. 
 
 Having thus indicated the general principles of classification which we adopt, we 
 now proceed to the more detailed consideration of amides, amines, and alkalamides. 
 It is not our purpose to give a complete list of these compounds, but merely to cite a 
 sufficient number of them to illustrate our classification ; and to enumerate the prin- 
 cipal reactions by which the formation and decomposition of each group is effected. 
 
170 AMIDES. 
 
 AMIDES. 
 I. Monamides or Amides. 
 
 1. Primary Amides. They represent 1 molecule of ammonia, in which I atom of 
 hydrogen is replaced by a monatomic acid-radicle (of a monobasic acid) : 
 
 Acetamide N.C 2 H 3 O.IP 
 
 Propionamide N.C 3 H 5 O.H 2 
 
 Benzamide N.C 7 H 5 O.H 2 
 
 Cyanamide N.CN.H 2 
 
 Sulphophenylamide N.C 6 H 5 S0 2 .H 2 . 
 
 They differ from the ammonium-salt of their acids in containing the element of 
 1 atom of water less : 
 
 C 2 H 3 2 (NH 4 ) - H 2 = N.C 2 H 3 O.H 2 
 
 Acet. amm. Acetamide. 
 
 They are formed : 1. By the action of ammonia on anhydrides (G-erhardt). 
 (C'H 5 0) 2 + NH S = C 7 H S O.H.O + N.C 7 H 5 O.H 2 
 
 Benzole anhyd. Benzole acid. Benzamide. 
 
 2. By the action of ammonia (Liebig and Wohler), or of carbonate of ammonium 
 (G erhardt) on the chlorides of acid-radicles : 
 
 CNC1 + NH 3 = HC1 + N.CN.H 2 
 
 Chloride of Cyanamide. 
 
 cyanogen. 
 
 This method is especially adapted to the formation of those amides which are insoluble 
 or nearly so, in water. 
 
 3. By the action of ammonia on ethers : 
 
 C 2 H 8 9.C 2 H 5 .0 + NH 3 = C 2 H B + N.C 2 H 3 O.H 2 
 
 Acetic ether. Alcohol. Acetamide. 
 
 This method is peculiarly adapted to the formation of soluble amides. Glycerides, 
 with ammonia, also yield an amide, and glycerin. (Bert helot.) 
 
 4. Some primary amides have special methods of formation : e. g. benzamide is 
 formed by oxidising hippuric acid with peroxide of lead : 
 
 C 9 H 9 N0 3 + 30 = N.C 7 H 5 O.H 2 + 2C0 2 + H 2 
 
 Primary amides are mostly solid and crystalline, easily fusible, neutral to test paper, 
 volatile without decomposition. Some of them, e. g. acetamide, combine with acids : 
 others e. g. benzamide, can exchange 1 atom of hydrogen for a metal, forming metallic 
 salts, or alkalamides. They are generally soluble in alcohol or ether : some in water. 
 
 Reactions. 1. Boiled with acids or with alkalis (some with water), they take up 
 H 2 and regenerate the acid and ammonia. 
 
 2. Treated with phosphoric anhydride, they lose H 2 0, and yield the corresponding 
 nitrile. The same reaction frequently takes place when they are passed in the state of 
 vapour over caustic lime. 
 
 N.C 2 H 3 O.H 2 - H 2 = N.C 2 H 3 
 
 Acetamide. Aceto- 
 
 nitrile. 
 
 3. Treated with pentachloride of phosphorus, they behave as though they were 
 oxides, yielding oxychloride of phosphorus, and the chloride of the radicle which they 
 may be supposed to contain, if derived from the type HHO (Gerhard t): 
 
 C 7 H 6 N.H.O + PCI 5 = PC1 3 + HC1 + C 7 H 6 N.C1 
 
 Benzamide. Chloride of 
 
 benzamyl. 
 
 The chloride thus formed is readily decomposed by heat, frequently below 100 C. 
 into hydrochloric acid and the corresponding nitrile, C 2 H 4 NC1 = HC1 + N.C 2 H 3 
 (aceto-nitrile). 
 
 4. With nitrous acid they yield their corresponding acid, with evolution of nitrogen : 
 
 N.C 7 H 5 O.H 2 + N0 2 H = NN + H 2 + C 7 H 6 2 
 
 Benzamide. Benzoic 
 
 acid. 
 
 2. Secondary Amides. They represent 1 molecule of ammonia, in which 2 atoms 
 of hydrogen are replaced : (a) by 2 monatomic acid-radicles, (b) by 1 diatomic acid- 
 radicle of a (dibasic acid). 
 
AMIDES. 171 
 
 a. H 2 are replaced by 2 monatomic radicles : 
 
 Diacetamide . . . . . . N.(C 2 H 3 0) 2 .H 
 
 Sulphophenyl-benzamide .... N.C 6 H 5 S0 2 .C 7 H 5 O.H 
 
 They are formed: 1. By the action of chlorides of acid-radicles on primary amides, 
 or their metallic salts (Gferhardt) : 
 
 N.C 6 H 5 S0 2 .H 2 + C 7 H 5 O.C1 = HC1 + N.C 6 H 5 S0 2 .C 7 H 5 O.H. 
 
 Sulphophenylamide Chloride of Sulphophenyl-benzamide. 
 
 benzoyl. 
 
 2. By action of dry hydrochloric acid on primary amides, at a high temperature 
 (Strecker): 
 
 2(N.C 2 H 3 O.H 2 ) + HC1 = NH 4 C1 + N.(C 2 H 3 0) 2 .H 
 
 Acetamide. Diacetamide. 
 
 These amides are readily seluble in ammonia. They exhibit acid properties, red- 
 dening litmus, and exchanging their remaining atom of hydrogen for a metal: the 
 metallic salts thus formed dissolve in ammonia, producing compounds which Grerhardt 
 regards as dialkalamides, but which, as they contain only monatomic radicles, it is 
 perhaps preferable to regard as monalkalamides containing a compound ammonium : 
 
 N.C 6 H 5 S0 2 .C 7 H 5 O.Ag. + NH 3 = N.C 6 H 5 S0 2 .C 7 H 5 O.NAgH 3 (monalkalamide). 
 or N 2 .C 6 H 5 S0 2 .C 7 H 5 O.Ag.H 3 (dialkalamide). 
 
 According to Grerhardt (Ann. Ch. Phys. [3] liii.), penfcachloride of phosphorus acts 
 on secondary amides in the same way as on primary amides : 
 
 N.C 6 H 5 S0 2 .C 7 H 5 O.H + PCI 5 = PCPO + HC1 + N(C 7 H 5 )(C 6 H 5 S0 2 )C1 
 
 Sulphophenylbenzamide. Chloride ofsulphophenyl- 
 
 and the chloride formed is decomposed by heat : 
 
 N(C 7 H 5 )(C 6 H 5 S0 2 )C1 = N.C 7 H 5 + C 6 HS0 2 .C1 
 
 Benzo- Chloride of 
 
 nitrile. sulphophenyl. 
 
 b. H 2 are replaced by 1 diatomic radicle. These are the bodies generally called 
 imides, being regarded as containing imidogen, NH. Though we reject this view of 
 their constitution, we retain the name for convenience sake. 
 
 Carbimide (cyanic acid) N.(CO)".H 
 
 Succinimide N.(C 4 H 4 2 )" . H 
 
 Camphorimide N.(C IO H H 2 )".H. 
 
 They differ from the acid ammonium-salts of their acids by containing 2 atoms of 
 water less : 
 
 C 4 H 4 4 (NH 4 )H - 2H 2 = N.C 4 H 4 3 .H 
 
 Acid succinate of Succinimide. 
 
 ammonium. 
 
 They are formed much more easily than secondary amides (a) : 
 
 1. By heating the acid ammonium-salts of dibasic acids. 
 
 2. By heating primary diamides : 
 
 N 2 .C 4 H 4 3 .H 4 = N.C 4 H 4 2 .H + NH S . 
 
 Succinamide. Succinimide. 
 
 3. By heating amic acids (Laurent): 
 
 KC 10 H 14 8 .H 2 .H.O = H 2 + N.C 10 H I4 2 .H 
 
 Camphoramic acid. Camphorimide. 
 
 4. By heating dibasic anhydrides with ammonia : 
 
 C 4 H 4 2 .0 + NH 3 = H 2 + KC 4 H 4 2 .H 
 
 Succinic anhy- Succinimide. 
 
 dride. ' 
 
 Imides possess decided acid properties, and readily exchange their basic hydrogen 
 for a metal ; carbimide in fact is identical with cyanic acid. 
 
 Reactions. 1. Boiled with acids or alkalis, they take up 2H 2 and regenerate the 
 dibasic acid and ammonia : 
 
 KC 4 H 4 2 .H + 2H 2 = C 4 H 4 4 .H 2 + NH 3 . 
 Secondary amides (a) also exhibit this reaction. 
 
 2. Boiled with dilute ammonia, they form the ammonium-salt of the corresponding 
 amic acid : 
 
 N.C 4 H 4 2 .H + NH 4 .HO = N.C 4 H 4 2 .H 2 .NH 4 .0 
 
 Succinamate of amm. 
 
172 AMIDES. 
 
 3. Tertiary Amides. They represent 1 molecule of ammonia, in which all the 
 hydrogen is replaced : (a) by 3 monatomic, (6) by 1 diatomic and 1 monatomic, (c) by 
 1 triatomic, acid-radicle : 
 
 a. H 8 are replaced by 3 monatomic radicles : 
 
 Sulphophenyl-benzoyl-acetamide . . N.C 6 H 5 S0 2 .C 7 H 5 O.C 2 H 3 0. 
 
 b. H 3 are replaced by 1 diatomic and 1 monatomic radicle : 
 
 Sulphophenyl-succinamide . . . N.C 6 H 5 S0 2 .(C 4 H 4 2 )". 
 
 They are formed by the action of chlorides of acid-radicles on the metallic salts of 
 secondary amides (tertiary alkalamides) : 
 
 KC 6 H 5 S0 2 .C'H 5 O.Ag + C 2 H 8 O.C1 = AgCl + KC 6 H S S0 2 .C 7 H S O.C 2 H 3 
 N.C 4 H 4 2 .Ag + C 6 H 5 S0 2 .C1 - AgCl + KC 4 H 4 2 .C 6 H 5 S0 2 . 
 
 Their reactions are but little known. Boiled with dilute ammonia, the amides of class 
 (6) give the ammonium-salt of the corresponding amic acid : 
 
 N.C 4 H 4 2 .C 6 H 5 S0 2 + NH 4 .H.O = NC 4 H 4 2 .C 6 H 5 S0 2 .H.NH 4 .0. 
 
 Sulphophenyl-succina- Sulphophenyl-succinamate of 
 
 mide. ammonium. 
 
 c. H s are replaced by 1 triatomic radicle. To this group, by their reactions and 
 mode of formation, the following mineral compounds belong : 
 
 N.(PO)'" . Gerhardt's biphosphamide (phosphorylamide) = P0 4 (NH 4 )H 2 - 3H 2 
 N.N.'" . Free nitrogen (Nitroso-nitrile) = N0 2 .NH 4 - 2H 2 O 
 
 N.(NO)'" . Nitrous oxide. (Nitro-nitrile) = N0 3 .NH 4 - 2H 2 0. 
 
 II. Diamides. 
 
 1. Primary Diamides. They represent 2 molecules of ammonia in which 2 atoms 
 of hydrogen are replaced by 1 diatomic acid-radicle. 
 
 Sulphamide . . . . . N 2 .(S0 2 )".H 4 
 
 Oxamide N 2 .(C 2 2 )".H 4 
 
 Succinamide N 2 .(C 4 H 4 2 )".H 4 
 
 Carbamide (urea) .... N 2 .(CO)".H 4 
 
 They differ from the normal ammonium-salts of their acids in containing 2 atoms of 
 water less : 
 
 C 2 4 (NH 4 )* - 2H 2 = N 2 .C 2 2 .H 4 
 
 Oxalate of Oxamide. 
 
 ammonium. 
 
 They are formed 1. By the action of ammonia on ethers : 
 
 C*0 4 (C 2 H 5 ) 2 + 2NH 3 = 2C 2 H d O + N 2 .C 2 2 .H* 
 
 Oxalic ether. Oxamide. 
 
 2. By the action of ammonia on chlorides of acid-radicles : 
 
 C 4 H 4 2 .C1 2 + 2NH 3 = 2HC1 + N 2 .C 4 H*0 2 .H* 
 
 Chloride of Succinamide. 
 
 succinyl. 
 
 3. By heating normal ammonium-salts of dibasic acids (Dumas). 
 
 4. By the action of ammonia on imides (Wohler) : 
 
 N.CO.H + NH 3 = N 2 .CO.H* 
 
 Carbimide. Carbamide. 
 
 By the action of ammonia on dibasic anhydrides, not primary diamides, but amic 
 acids, are generally formed. 
 
 Many primary diamides exhibit decidedly basic properties, combining with acids 
 and forming definite salts : e. g. urea, asparagine, &c. 
 
 Eeactions. 1. Many of them, when heated, evolve ammonia and yield imides. 
 
 2. Boiled with acids or alkalis, they take up 2H 2 0, and regenerate the acid and am- 
 monia : 
 
 N 2 .C 2 2 .H 4 + 2H 2 = C 2 4 .H 2 + 2NIP. 
 
 3. With nitrous acid, they regenerate their dibasic acid, with evolution of nitrogen 
 (Piria, Malaguti): 
 
 N 2 .C 2 2 .H 4 + 2N0 2 H = 2NN + C 2 4 .H 2 + 2H 2 0. 
 
 Oxamide. Oxalic acid. 
 
 Intermediate between primary and secondary diamides must be classed the bodies 
 
AMIDES. 173 
 
 lately discovered by Zinin (Ann. Ch. Phys. [3] xliv. 57), which he describes as 
 ureas, in which 1 atom of hydrogen is replaced by an acid radicle. They are of course 
 diamides, in which 3 atoms of hydrogen are replaced, 2 by a diatomic, and 1 by a mon- 
 atomic radicle. 
 
 Acetocarbamide (acetyl-urea) . . N 2 .CO.C 2 H 3 O.H S 
 Benzoearbamide (benzoyl-urea) . . N 2 .CO.C 7 H 5 O.H 3 . 
 
 They are formed by the action of chlorides of acid-radicles on urea : 
 N 2 .CO.H 4 + C 2 H 3 O.C1 = HC1 + N 2 .CO.C 2 H 8 OH 3 
 
 Carbamide. Chloride of Acetocarbamide. 
 
 acetyl. 
 
 Attempts to replace more than 1 atom of hydrogen in urea by an acid-radicle, have 
 hitherto failed. 
 
 > These bodies are crystallisable, and do not combine with acids. They are not 
 volatile, being decomposed by heat into cyanuric acid and a primary amide : 
 3(N 2 .CO.C 2 H 3 O.H 3 ) = C'N 3 3 H 3 + 3(N.C 2 H S O.H 2 ) 
 
 Acetocarbamide. Cyanuric acid. Acetamide. 
 
 Here too must be placed Gerhardt's phosphamide (Ann. Ch. Phys. [3] xviii.) 
 N 2 .(P())'".H 3 , formed by saturating pentachloride of phosphorus with ammonia, and boil- 
 ing with water : 
 
 PGP + 2NH 3 + H 2 = N 2 .PO.H 3 + 5HC1. 
 
 It differs from monacid phosphate of ammonium by the elements of 3 atoms of water : 
 P0 4 (NH 4 ) 2 H - 3H 2 = N 2 .PO.H 3 . 
 
 2. Secondary Diamides. They represent 2 molecules of ammonia, in which 4 
 atoms hydrogen are replaced by 2 diatomic acid-radicles, or by 1 diatomic and 2 
 monatomic radicles. 
 
 None of these have yet been formed. (Handwb.) 
 
 3. Tertiary Diamides. They represent 2 molecules of ammonia, in which all 
 the hydrogen is replaced by acid-radicles, one of which at least must be dibasic : 
 
 Trisuccinamide .... N 2 .(C 4 H 4 2 ) 3 
 
 Succinyl-disulphophenyl-dibenzamide . N 2 .(C 4 H 4 2 ).(C 6 H 5 S0 2 ) 2 .(C 7 H S 0) 2 . 
 
 They are formed by the action of chlorides of acid-radicles on the silver-salts of 
 secondary amides : 
 
 2(N.C 4 H 4 2 .Ag) + C 4 H 4 2 .C1 2 + N 2 .(C 4 H 4 2 ) 3 + 2AgCl. 
 
 Argentosuccinamide. Chloride Trisuc- 
 
 of succinyl. cinamide. 
 
 III. Triamides. 
 
 1. Primary Triamides. They represent 3 molecules of ammonia, in which 3 
 atoms of hydrogen are replaced by a triatomic acid-radicle : 
 
 Phosphamide .... N S .(PO)'".H 6 . 
 Citramide N 3 .(C 6 H 5 4 )'".H 6 . 
 
 They differ from the normal ammonium-salts of their acids by containing 3H 2 less : 
 C 6 H 5 7 (NH 4 ) 3 - 3H 2 O = N 3 .C 6 H 5 4 .H 6 . 
 
 Citrate of amm. Citramide. 
 
 Phosphamide is formed by the action of ammonia on oxychloride of phosphorus : 
 POC1 3 + 6NH 3 = 3NH 4 C1 + N'.PO.H 8 . (Schiff. Ann. Ch. Pharm. ci. 300.) 
 Citramide is formed by the action of ammonia on citric ether : 
 
 C 6 H 5 4 .(C 2 H 5 ) 3 .0 3 + 3NH 3 = N 3 .C 6 H 5 4 .H 6 + 3(C 2 H 5 .H.O) 
 
 Citric ether. Citramide. Alcohol. 
 
 Heated with acids or alkalis, they take up 3H 2 0, and regenerate their acid and 
 ammonia. 
 
 2. Secondary Triamides. ) They represent respectively 3 mols. ammonia, in which 
 
 3. Tertiary Triamides. \ two-thirds and the whole of the hydrogen is replaced 
 by acid-radicles, one of which at least must be triatomic. 
 
 No member of either of these groups has yet been formed. 
 
 Gerhardt (Chim. org. iv. p. 767) regards melam, C 3 H 6 N 6 , as a primary triamide, 
 N 3 .C 3 N 3 .H 6 : -and indeed we may admit the existence of a triatomic radicle, C 3 N 3 , and 
 regard hydrocyanic acid as tribasic, C 3 N 3 H 3 : otherwise such compounds as ferro- 
 cyanide of potassium, C 3 N 3 PeK 2 , present the anomaly of bodies deriving from a triple 
 type (H 3 C1 3 ), and yet containing only monatomic radicles. 
 
174 AMIDES. 
 
 AMINE.S. 
 I. Monamlnes or Amines. 
 
 1. Primary Amines. They represent 1 molecule of ammonia, in which 1 atom of 
 hydrogen is replaced by a monatomic base-radicle, whether a metal or an organic 
 radicle. They are sometimes called amide-bases. 
 
 Potassamine tf.KH 2 
 
 Platinamine N.Pt.H 2 . 
 
 Methylamine. . . . N.CH'.H 2 
 
 Ethylamine N.C'H'.H 2 
 
 Phenylamine (Aniline) . . . N.C 6 H 5 .H 2 . 
 
 Primary amines containing metals are generally obtained by the action of ammonia 
 on the metal or its oxide. Zincamine is formed by the action of ammonia on zinc- 
 ethyl: ZnC 2 H 5 + NH 3 = H.C 2 H 5 + NZnH 2 . When treated with water or acids, 
 they are mostly decomposed, like primary amides, yielding ammonia and the hydrate 
 of the metal. 
 
 Primary amines containing organic radicles are formed : 
 
 1. By action of ammonia on hydrobromic or hydriodic ethers (Hofmann) : 
 
 CH 3 I + NH 3 = HI + N.CH 3 H 8 
 
 Iodide of Methylamine. 
 
 methyl 
 
 2. By action of potash on cyanic or cyanuric ethers (Wurtz): 
 
 N.CO.CH 3 + K 2 H 2 2 = CO.K 2 .0 2 + N.CH 3 .H 2 
 
 Cyanate of Carbonate of Metliyl- 
 
 methyl. potassium. amine. 
 
 3. By action of reducing agents, viz. alkaline hydrosulphates (Zinin), acetate of 
 iron (Bechamp), on certain nitro-conjugated hydrocarbons: 
 
 C 6 H 5 (N0 2 ) + H 6 = 2H 2 + N.C 6 H 5 .H 2 
 
 Nitrobenzene. Phenylamine. 
 
 Their formation is also observed in the dry distillation of several nitrogenised organic 
 substances. (For the various modes of formation of monamines in general, primary, 
 secondary, and tertiary, see K^kule', Lehrb. d. org. Chemie, pp. 451 456.) 
 
 These primary amines are mostly liquid, boiling at a low temperature, and volatile 
 without decomposition. They strikingly resemble ammonia in all their properties: 
 like it they have a strong alkaline reaction ; they combine directly with acids, forming 
 salts, whence they are expelled by the fixed alkalis ; they precipitate metallic solu- 
 tions ; with anhydrides, ethers, and chlorides of acid-radicles, they react precisely like 
 ammonia (forming alkalamides, <?.#.), and with hydriodic ethers they form diamides. 
 With nitrous acid they yield nitrous ether or alcohol, with evolution of nitrogen : 
 
 KC 2 H 5 .H 2 + 2N0 2 H = NN + 2H 2 + N0 2 .C 8 H 5 
 Ethylamine. Nitrous ether. 
 
 N.C'HAH 2 + N0 2 H = NN + H 2 + C 6 H 6 
 
 Phenylamine. Phenylic 
 
 alcohol. 
 
 In this group must also be included those amines whose radicle contains chlorine, 
 bromine, iodine, or nitryl (NO 2 ), substituted for 1, 2, or 3 atoms of hydrogen : e. q. 
 Dichlorethylamine, N.C 2 H 3 C1 2 .H 2 , Chlorophenylamine, N.C 6 H 4 C1.H 2 , Dichlorphe- 
 nylamine, N.C 6 H 3 C1 2 .H 3 , Trichlorphenylamine, N.C 6 H 2 C1 3 .H 2 , Nitrophenylamine, 
 N.C 6 H 4 .(NO-).H 2 , &c. Their alkaline properties are less marked, the greater the num- 
 ber of atoms of chlorine, &c. they contain. They are formed mostly either by the 
 direct action of chlorine, &c. on amines, or by the metamorphoses of other conjugated 
 compounds. Nitrophenylamine is formed by the reduction of dinitrobenzene by 
 hydrosulphate of ammonium, just as phenylamine results from the reduction of nitro- 
 benzene by the same agent. 
 
 2. Secondary Amines. They correspond to 1 molecule of ammonia, in which 
 2 atoms of hydrogen are replaced by two monatomic base-radicles. They are sometimes 
 called Imide-bases. 
 
 Dimethylamine N.(CH S ) 2 .H. 
 
 Methylethylamine .... N.CH 3 .C 2 H 5 .H. 
 Ethylphenylamine .... N.C 2 H.C 8 H 5 .H. 
 They are formed by the action of hydriodic ethers on primary amines : 
 
 N.CH 3 .H 2 + C 2 H 5 I = HI + N.CH 3 .C 2 H. 5 H 
 
 Methylamine. Iodide of Methylethylamine. 
 
 ethyl. 
 
AMIDES. 175 
 
 In properties and reactions, they closely resemble primary amines : but they are in 
 general less volatile. 
 
 We must also regard as secondary amines two alkaloids, which have not yet been 
 formed artificially : 
 
 Piperidine . N.(C 5 H')".H. 
 
 Conine N.(C S H 14 )".H. 
 
 The chemical relations of the radicles contained in these compounds are as yet 
 unknown to us ; and we cannot determine whether they are single diatomic radicles, 
 or whether they are made up of two monatomic radicles. 
 
 3. Tertiary Amines. They represent 1 molecule of ammonia, in which all the 
 hydrogen is replaced : (a) by 3 monatomic, (b) by 1 diatomic and 1 monatomic, (c) by 
 1 triatomic base-radicle. 
 
 a. H 3 are replaced by 3 monatomic radicles (Nitrile -bases). 
 
 Tripot-assamine N.K 3 
 
 Trimercuramine . . . . . . N.Hg 3 
 
 Trimethylamine N.(CH 3 ) 3 
 
 Methyldiethylamine . . . . . N.CH 3 .(C 2 H 5 ) 2 . 
 
 Methylethylphenylamine .... N.CH 3 .C 2 H 5 .C 6 H 5 . 
 
 Those containing organic radicles are formed 1. By the action of hydriodic ethers 
 on secondary amines : 
 
 N.(CH 3 ) 2 .H + C 2 HM = HI + K(CH 3 ) 2 .C 2 H 5 . 
 
 Dimethylamine. Iodide of Dimethylethylamine. 
 
 ethyl. 
 
 2. By the distillation of the salts of organic ammonium-bases : 
 
 N.(C 2 H 5 ) 4 .H.O = N.(C 3 H 5 ) 3 + C 2 H 4 + H 2 
 
 Hydrate of Triethyla- Ethylene. 
 
 tetrethylium. mine. 
 
 N(C 2 H 5 )M = K(C 2 H 5 ) 3 + C 2 H 5 I. 
 
 Iodide of 
 tetrethylium. 
 
 3. By action of ethylate of potassium on cyanic ether : 
 
 N.CO.C 2 H 5 + (C 3 H 5 ) 2 .K 2 .0 2 = N.(C 2 H 5 ) S + CO.K 2 .0 2 
 
 Cyanate of ethyl. 2'mol. ethylate Triethyla- Carbonate of 
 
 of potassium. mine. potassium. 
 
 This reaction is analogous to that of hydrate of potassium on cyanic ethers. (See 
 PRIMABY AMINES.) 
 
 Tertiary amines are generally similar in properties to primary and secondary amines : 
 they are less volatile than either. They are however distinguished by one important 
 reaction, which at the same time exhibits in the strongest light their analogy with 
 the type from which they are derived. When acted upon by hydriodic ethers, direct 
 combination takes place, an iodide of an organic ammonium-base being formed : 
 
 N.(C 2 H 5 ) 3 + C 2 H 5 .I = N(C 2 H 5 ) 4 .I 
 
 Iodide Of 
 tetrethylium. 
 
 These iodides are usually crystalline, soluble in water and alcohol : when treated with 
 oxide of silver, they yield iodide of silver, and a hydrate of the ammonium-base : 
 
 2[N(C 2 H 5 ) 4 .I] + Ag 2 + H 2 = 2AgI + 2[N(C i H 5 ) 4 .H.O] 
 
 Hydrate of 
 tetrethylium. 
 
 These hydrates are crystalline and soluble in water : they are powerful alkalis ; in 
 some reactions they resemble the fixed alkalis, liberating ammonia from ammoniacal 
 salts, and decomposing ethers into acid and alcohol. Precisely, therefore, as ammonia 
 
 (nitride of hydrogen) NH 3 , combines with hydriodic acid (iodide of hydrogen) HI, 
 forming iodide of ammonium, NH 4 I ; so triethylamine (nitride of ethyl) N(C 2 H 5 ) 3 , 
 combines with iodide of ethyl, C 2 H S I, forming iodide of tetrethylium, N(C 2 H 5 ) 4 I. 
 Just as we have the hypothetical compound ammonium, NH 4 , playing the part of 
 potassium, sodium, and other metals, and replacing the basic hydrogen in acids to 
 form salts so we have the hypothetical compound tetrethylium, N(C 2 H 5 ), performing 
 precisely the same metallic functions. The analogy could not be more complete. 
 
 b. H 3 are replaced by 1 diatomic and 1 monatomic radicle: Hofmann's ethylene- 
 phenylamine, N.(C 2 H 4 )".C 6 H 5 . 
 
176 AMIDES. 
 
 c. H 3 are replaced by 1 triatomic radicle (Nitriles). 
 
 Acetonitrile (cyanide of methyl) N.(C 2 H 3 )'" 
 
 Propionitrile (cyanide of ethyl) K(C 3 H 5 )'" 
 
 Benzonitrile (cyanide of phenyl) .... N.(C 7 H r> )'". 
 
 They are formed 1. By the action of heat or dehydrating agents (e.g. phosphoric 
 
 anhydride) on ammoniacal salts of monobasic acids : 
 
 C 2 H 3 2 .NH 4 - 2H 2 = N.C 2 H 3 . 
 
 Acetate of amm. Acetonitrile. 
 
 These nitriles differ from primary amides in containing H-0 less. 
 
 2. By the action of cyanide of potassium on sulphate of ethyl and potassium (or a 
 homologous salt), or on hydriodic ethers : 
 
 S0 2 .(C 2 H 5 ).K0 2 + CN.K = S0 2 .K 2 .0 2 + CN.C 2 H 5 
 
 Sulphate of ethyl Sulphate of Cyanide of 
 
 aud potassium. potassium. ethyl or 
 
 propio-nitrile. 
 
 This mode of formation shows that nitriles may also be regarded as cyanides 
 (N.C 2 H 3 = CN.CH 3 ), deriving from the type C1H : and it is in this light that they 
 are usually considered. But, if we consider their formation from ammoniacal salts, 
 and their behaviour when boiled with acids or alkalis, when they regenerate their 
 acid and ammonia, NC 2 H 3 + KHO + H 2 = C'H'O-K + NH 3 , we may fairly 
 regard them as deriving from the same type with amides. And we are led to consider 
 them as amines rather than as amides, by the fact that, in one of them at least, the 
 radicle is clearly a basic one ; in propio-nitrile, N.C 3 H 5 , the radicle is glyceryl, the 
 triatomic radicle of the triatomic alcohol, glycerin, C 3 H 5 .H 3 .0 3 . Moreover, that they 
 resemble amines in the property of combining with acids, is shown by the compounds 
 which Grerhardt obtained by the action of pentachloride of phosphorus on primary 
 amides (q. .) CTBFNC1 = N.C'H 5 + HC1. 
 
 In order to show the connection between nitriles and the acids from whose 
 ammonium-salts they are formed, e.g. of acetonitrile N.C-H 3 , with acetic acid, C 2 H 4 2 , 
 and acetic compounds generally, it may be observed that acetic compounds may be 
 represented as containing the triatomic radicle C 2 H 3 . Thus acetic acid may be written 
 (C 2 H 3 ) '.H.O 2 , deriving from the double type H 4 2 : acetamide, N.H.C 2 H 3 .H.O, de- 
 riving from the double type NH 3 + H 2 : chloride of acetyl, C1.C 2 H 3 .O, deriving from 
 the double type C1H + H 2 : acediamine, N 2 .C 2 H S .H 3 , deriving from the double type 
 N 2 H. 
 
 "We have already seen that, when an amine which contains any replaceable 
 hydrogen (primary or secondary amines), is treated with the iodide of an organic basic 
 radicle, the result is the replacement of the basic hydrogen by the organic radicle : 
 but that when tertiary amines, in which all the basic hydrogen is already replaced, are 
 similarly treated, the result is a direct combination of the iodide with the amine. 
 Hence we are enabled to class as tertiary amines many natural organic alkalis, which 
 combine directly with organic iodides ; of whose constitution, as they cannot be formed 
 artificially, we should otherwise be ignorant. Among these are the following homo- 
 logous alkalis, obtained by the dry distillation of animal matter : 
 
 Pyridine N.C 5 H 5 
 
 Picoline N.C 6 H 
 
 Lutidine N.C'H 9 
 
 Collidine N.C 8 H 
 
 Parvoline N.C'H 13 . 
 
 Also the numerous vegetable alkalis or alkaloids (quinine, strychnine, morphine, &c.), 
 which have been extracted from plants. The majority of these latter compounds 
 contain oxygen-radicles : as many of them contain 2 atoms of nitrogen, it is possible 
 that they must be regarded as diamines. How many radicles they may contain, we 
 have as yet no means of determining. 
 
 II. Diamines. 
 
 1. Primary Diamines. ) They represent 2 molecules of ammonia, in which 
 
 2. Secondary Diamines. \2 and 4 atoms of hydrogen are replaced by 1 and 2 
 diatomic base-radicles. The only representatives of these groups are the compounds 
 lately obtained by Hofmann, by the action of bromide of ethylene on ammonia; they 
 contain the diatomic radicle ethylene, C 2 H 4 : 
 
 Ethylenamine ...... N 2 .(C 2 H 4 ).H 4 
 
 Diethylenamine N 2 .(C 2 H 4 ) 2 .H 2 . 
 
AMIDES. 177 
 
 They are thus formed : 
 
 C 2 H 4 .Br 2 + N 2 H 6 - 2HBr + N 2 .C 2 II 4 .H* 
 
 Bromide Ethylenaniine. 
 
 of ethylene. 
 
 2C 2 H 4 Br 2 + N 2 H fi = 4HBr + N 2 .(C 2 H 4 ) 2 .H 2 
 
 Di-ethylenamine. 
 
 Intermediate between secondary and tertiary diamines, is Hofmann's diphenyl- 
 formylamine, N 2 .(C 6 H 5 ) 2 .CH.H, obtained by the action of chloroform on phenylaniine ; 
 2(N.C 6 H 5 .H 2 ) + CHOP = N 2 .(C 6 H 5 ) 2 .CH.H + 3HC1. 
 
 3. Tertiary Diamines. They represent 2 mols. ammonia, in which all the hydrogen 
 is replaced ; (a) by 3 diatomic, (b) by 2 diatomic, and 2 monatomic base-radicles. 
 
 a. Hofmann has obtained triethylenamine, N 2 .(C-H 4 )', by the reaction : 
 
 3C 2 H 4 Br 2 + N 2 H 6 = 6NHBr -h N 2 .(C 2 H 4 ) 3 . 
 In this group may be classed the compounds known as hydramides : 
 
 Benzhydramide (hydrobenzamide) .... N 2 .(C 7 H G ) 3 
 
 Salhydramide N 2 .(C 7 H 6 0) 8 . 
 
 They are obtained by the action of ammonia on certain aldehydes : 
 3C 7 H 6 -f- N 2 H 6 = 3H 2 + N 2 .(C 7 H 6 ) 3 
 
 Benzoic al- Benzliydra- 
 
 dehyde. mide. 
 
 They are crystalline, insoluble in water, soluble in alcohol, not volatile without 
 decomposition. They are decomposed by hydrosulphuric acid, yielding sulph-aldehydes. 
 (Cahours.) 
 
 N 8 .(C 7 H 6 ) 3 + 3H 2 S = N 2 H + 3C 7 HS. 
 
 The view here taken of the constitution of hydrobenzamide is confirmed by its 
 formation from chlorobenzol, C 7 H 6 C1 2 , and ammonia (Engelhardt), by the manner 
 in which iodide of ethyl reacts upon it (B or o dine), and by the existence of a number 
 of bodies obtained from chlorobenzol, which may be regarded as the methylate, 
 ethylate, acetate, valerate, benzoate, &c. of the diatomic radicle C T H 6 . 
 
 b. Hofmann has obtained diethylene-diphenylamine, N 2 .(C''H 4 ) 2 (C 6 H 5 ) 2 , by the action 
 of chloride of ethylene on phenylamine : 
 
 2(C 2 H 4 .C1 2 ) + 2(N.C 6 H 5 .H 2 ) = 4HC1 + N 2 .(C 2 H 4 ) 2 .(C 6 H 5 ) 2 . 
 
 Here too should probably be classed cyanogen, or oxalo-nitrile, N 2 C 2 , which bears 
 the same relation to normal oxalate of ammonium that acetonitrile does to acetate of 
 ammonium : 
 
 C 2 0'.(NH 4 ) 2 - 4H 2 = N 2 C ? . 
 C 2 H 3 2 .NH 4 - 2H-0 = N.CH 3 ; 
 also nitride of boron, N 2 B 2 . 
 III. Triamines. 
 
 2 SeooiSrv I They re P resent 3 molecules of ammonia, in which 3, 6, or 9 atoms 
 
 3 Tertia ) f h y dro g en are replaced by 1, 2, or 3 triatomic basic radicles. 
 The only triamine known is Frankland and Kolbe's Cyanethine, C 9 H 15 N 3 , which, 
 
 according to Hofmann, should be regarded as triglycerylamine, N 3 .(C 3 H 5 ) 8 , a tertiary 
 triamine. 
 
 Tetramlnes and Pentamines. We know but little of any complex ammonia- 
 molecules of a higher order than the triamines ; nevertheless it appears that under 
 certain circumstances, four, five, or even a greater number of atoms of ammonia are 
 capable of coalescing into a complex molecule. 
 
 The only well characterised tetramines with which we are acquainted are qlycosiiir, 
 N 4 .C (i H 6 , a product of the action of ammonia on glyoxal, which may be regarded rs 
 
 N'(C'4r 2 ) 3 , and hcxamethylenamine, N 4 .C 6 H 12 , formed by the action of ammonia on 
 
 dioxymethylene, which maybe written N 4 (C'-H 4 ) 3 (Buttlerow, Bullet, dela Soc. Chim. 
 de Paris, i. 221.) There are also some natural bases containing 4 at. nitrogen, e. ci. 
 caffi-ine, C 8 H 10 N 4 2 , and thcobromine, C 7 H 8 N 4 2 , but we know nothing of the radicle* 
 which they contain. 
 
 VOL. I. N 
 
;78 AMIDES. 
 
 Pentamines appear to be produced by the action of ammonia on certain metallic 
 oxides. Some of the ammoniacal compounds of cobalt appear to be of this character ; 
 but further investigation is necessary to give accurate ideas of their constitution. 
 
 FHOSPHINES, AR SINES, STIBINES. In connection with the basic derivatives of 
 ammonium, we must also mention a class of bodies derived from phosphoretted hydrogen, 
 PH 3 , arsenetted hydrogen, AsH 3 . and antimonetted hydrogen, SbH 3 , by the substitu- 
 tion of alcohol-radicles for the hydrogen. All the compounds thus formed, are basic, 
 like the alcoholic derivatives of ammonia, and form salts of exactly analogous charac- 
 ter. Up to the present time, however, the only phosphines, arsines, and stibines, that 
 have been obtained are those in which the whole of the hydrogen in the type is 
 replaced by an equivalent quantity of an alcohol- radicle, e. g. : 
 
 Triethylphosphine P(C 2 H 5 ) 3 
 
 Trimethystibine Sb(CH 3 ) 3 
 
 These bases have not yet been obtained by direct substitution from the hydrides of 
 phosphorus, arsenic and antimony; but they are produced, either by submitting a 
 metallic compound of phosphorus, arsenic, or antimony to the action of the iodides, 
 bromides or chlorides of the alcohol radicles, e. g. : 
 
 Na 3 As + 3C 2 H 5 I = 3NaI + As(C 2 H 5 ) 3 
 
 Trisodic Iodide of Triethyl- 
 
 arseuide. ethyl. arsine. 
 
 or, better in most cases, by treating the metallic compounds of the alcohol-radicles 
 with the iodides, bromides, and chlorides of phosphorus, arsenic and antimony ; thus, 
 
 3CH 3 Zn + PCI 3 = 3ZnCl + P(CH 3 ) 3 
 
 Zinc-methyl. Trirmthyl- 
 
 pliosphine. 
 
 These compounds, when treated with the bromides or iodides of the alcohol-radicles, 
 behave exactly like the corresponding nitrogen-bases, producing the bromides or 
 iodides of bases containing 4 at. of the alcohol-radicle and belonging to the ammonium 
 type: e.g.: 
 
 P(C 2 H 5 ) 3 + C 2 H 5 I = P(C 2 H 5 ) 4 I 
 
 Triethyl- Iodide of Iodide of 
 phosphine. ethyl. ethylphos- 
 
 nium. 
 
 P(CH 3 ) 3 + C 2 H 5 I = P(CH 3 ) 3 (C 2 H 5 )I. 
 
 Trimethyl- Iodide of trimethyl- 
 
 phosphine. ethyl-phosphonium. 
 
 The phosphines treated with diatomic bromides (dibromide of ethylene, for example), 
 yield, among other products, the monobromide of a phosphonium-molecule, in which the 
 'fourth atom of hydrogen is replaced by a brominated alcohol-radicle ; thus triethyl- 
 phosphine, treated with dibromide of ethylene, yields the monobromide of broinethyl- 
 triethyl-phosphonium : 
 
 P(C 2 H 5 ) 3 + C 2 H 4 Br 2 = P[(C 2 H 4 Br)'.(C 2 H 5 ) 3 ]Br. 
 (See AMMONIUM-BASES.) 
 
 ALKALAMIDES. 
 I. Monalkalamides or Alkalamides. 
 
 1. Secondary Alkalamides. They represent 1 vol. ammonia in which 2 atoms 
 of hydrogen are replaced, one by an acid, the other by a base radicle. 
 
 Mercurobenzamide N.Hg.C 7 H 5 O.H. 
 
 Argentosulphophenylamide .... N.Ag.C 6 H 5 S0 2 .H. 
 
 Ethylformamide N.C'HACHO.H. 
 
 Ethylacetamide N.C-H S .C 2 H 3 O.H. 
 
 Phenylbenzamide (benzanilide) .... N.C 6 H 5 .C'H 5 O.H. 
 
 Ethylcyanamide N.C 2 H 5 .CN.H. 
 
 Those which contain metals are formed by the action of primary amides on metallic 
 oxides ; they are decomposed by most acids, which remove their metal. Those con- 
 taining silver are readily attacked by chlorides of acid-radicles, yielding secondary 
 amides and chloride of silver : 
 
 N.Ag.C 6 HS0 2 .H + C'H 5 O.C1 = AgCl + N.C 6 H 5 S0 2 .C'H S O.H. 
 
 Argentosulphophe- Chloride of Sulphophenylbenzamide. 
 
 nylaimde. benzoyl. 
 
ALKALAMIDES. 179 
 
 Those containing organic base-radicles, are formed by the same reactions as primary 
 amides, a primary amine being substituted for ammonia : 
 
 li By action of primary amines on monobasic anhydrides (G-erhardt) : 
 
 N.C 6 H 5 .H 2 + (C 7 H 5 0) 2 = C 7 H 5 O.H.O + N.C 6 H 5 .C 7 H S O.H. 
 
 Phenylamine. Benzoic an- Benzoic acid. Phenylbenzamide. 
 
 hydride. 
 
 2. By action of primary amines on chlorides of acid-radicles (G-erhardt): 
 
 N.CIP.H 2 + C 2 H 3 O.C1 = HC1 + N.CH 3 .C 2 H 3 O.H 
 
 Methylaniine. Chloride of Methylacetamide. 
 
 acetyl. 
 
 3. By action of primary amines on ethers : 
 
 KC 2 H 5 .H 2 + C 2 H 3 O.C 2 H 5 .0 = C 2 H 5 .H.O + N.C S H 5 .C 2 H 8 O.H. 
 
 Ethylamine. Acetic ether. Alcohol. Ethylacetamide. 
 
 4. By action of monobasic acids on cyanic ethers (Wurtz) : 
 
 CHN.H.O + KC 2 H 5 .CO = CO.O + N.C 2 H 5 .CHO.H. 
 
 Formic acid. Cyanate of Carbonic Ethyl-formamide. 
 
 ethyl. anhyd. 
 
 They are crystalline, and generally do not combine -with acids ; boiled with acids 
 or alkalis, they take up H 2 0, and regenerate their acid and primary amine : 
 
 N.CH 5 .C 2 H 3 O.H + H 2 = N.C 6 H 5 .H 2 + C 2 H 8 O.H.O. 
 
 Phenylacetamide. Phenylamine. Acetic acid. 
 
 Those containing cyanogen act as weak alkalis, forming with concentrated acids com- 
 pounds which are decomposed by water. By heat they are decomposed in rather a 
 peculiar manner, yielding a tertiary alkalamide, and a kind of intermediate dialkala- 
 mide, which contains only monatomic radicles : 
 
 3(N.C 2 H 5 .CN.H) = N.(C 2 H 5 ) 2 .CN + N 2 .C 2 H 5 .(CN) 2 .H 3 
 
 Ethylcyanamide Diethylcyana- Ethyldicyandiamide. 
 
 mide. 
 
 According to G-erhardt (Ann. Ch. Phys. [3] liii. 307) secondary alkalamides are 
 acted upon by pentachloride of phosphorus in the same way as primary and secondary 
 amides : 
 
 N.C 6 H 5 .C 7 H*O.H + PCI 5 = N(C 7 H 5 )'"(C 6 H 5 )C1 + POC1 3 + HC1. 
 
 Phenyl-benzamide. Chloride ot phenyl- 
 
 benzamidyl. 
 
 2. Tertiary Alkalamides. They represent 1 molecule of ammonia in which all 
 the hydrogen is replaced ; (a) by 1 basic and 2 acid monatomic radicles ; (6) by 2 basic 
 and 1 acid monatomic radicles ; (c) by 1 basic monatomic, and 1 acid diatomic radicle. 
 
 a. H 3 are replaced by 1 basic and 2 acid monatomic radicles : 
 
 Ethyl-diacetamide N.C 2 H 5 .(0 2 H 3 0) 2 
 
 Phenyl-dibenzamide N.CH 5 .(C 7 H 5 0) 2 
 
 They are formed : 
 
 1. By action of chlorides of acid-radicles on secondary alkalamides (Gerhardt 
 and Chiozza): 
 
 N.C 6 H 5 .C 7 H 5 O.H + C 7 H 5 O.C1 = HC1 + N.C 6 H 5 .(C 7 H 5 O) 2 . 
 
 Phenylbenzamide. Chloride of Phenyldibeiizamide. 
 
 benzoyl. 
 
 2. By action of monobasic anhydrides on cyanic ethers (Wurtz): 
 
 (C 2 H 8 0) 2 .0 + N.C 2 H 5 .CO = CO.O + N.C 2 H 5 .(C 2 H 3 0) 2 
 
 Acetic anhy- Cyaiiate of Ethyldiacetamide. 
 
 dride. ethyl. 
 
 They are neutral bodies, combining neither with acids nor with bases. 
 
 b. H 3 are replaced by 2 basic and 1 acid monatomic radicle: 
 
 Methyl-ethyl-cyanamide N.CH 3 .C-H 5 .CN 
 
 Diethyl-cyanamide N.(C 2 H 5 ) 2 .CN. 
 
 The only members of this group hitherto formed, contain cyanogen as the acid- 
 radicle. They are formed by the action of chloride of cyanogen on secondary amines 
 (Cahours and Cloez): 
 
 N.C 2 H 5 .C 6 H 5 .H + CKC1 = HC1 + KC 2 H S .C 6 H 5 .CN. 
 
 Ethylphenylamine. Ethylphenylcya- 
 
 namide. 
 
 They are liquid and volatile without decomposition. Heated with acids or alkalis, 
 
 N 2 
 
180 AMIDES. 
 
 they regenerate a secondary amine and cyanic acid, which latter is further decom- 
 posed into carbonic anhydride and ammonia : 
 
 K(C 2 H 5 ) 2 .CN + HHO = N.(C 2 H 5 ) 2 .H + CN.H.O. 
 
 Diethyl-c) r ana- Diethylamine. Cyanic acid, 
 
 mide. 
 
 N.CO.H -t- H 2 = NH 3 + CO.O 
 
 Cyanic acid. 
 
 c. H s are replaced by 1 monatomic baste, and 1 diatomic acid, radicle. As these 
 compounds correspond to those secondary amides which are commonly called imkles 
 we will retain the same termination for them : 
 
 Phenyl-succinimide (succinanile) .... N.C 6 H 5 .(C 4 H 4 2 )" 
 Ethyl-carbimide (cyanic ether) KC ; H 5 .(CO)" 
 
 "With the exception of cyanic ethers, the only members of this group that have been 
 studied are those containing phenyl as their basic radicle; they are commonly called 
 aniles. They are obtained by the action of phenylamine on dibasic anhydrides or 
 acids (probably also on the corresponding chlorides) : 
 
 N.C 6 H 5 .H 2 + C 10 H' 4 2 .0 = H 8 + N.C 6 H 5 .C 10 H"0 2 
 
 Camphoric Phenylcamphorimide. 
 
 anhydride. 
 
 N.C 6 H 5 .H 2 + C 10 H H 0'.H 2 .0 2 = 2H 2 + N.C 6 H 5 .C 10 H 14 2 . 
 
 Camphoric acid. 
 Boiled with dilute ammonia, they form the ammonium-salt of an amic acid : 
 
 N.C 6 H 5 .C 4 H 4 2 + NH 4 .H.O = 
 
 Phenylsuccinimide. Phenylsuccinamate of 
 
 ammonium. 
 
 Fused with potash, they regenerate phenylamine and their acid : 
 
 N.C 3 H 5 .C 4 H 4 2 + K 2 H 2 2 = C 4 H 4 2 .K 2 .0 + KC 6 H 5 .H 2 . 
 
 Succinate of 
 potassium. 
 
 As cyanic acid may be regarded as carbimide, cyanic ethers may obviously be 
 regarded as alkalimides. With potash they exhibit the same reaction as the foregoing 
 alkalimides : 
 
 N.C 2 H 5 .CO + K 2 H 2 2 = CO.K 2 .0 2 + N.C 2 H 5 .H 2 . 
 
 By the action of water or ammonia, they form Dialkalamides (compound ureas) : 
 N 2 .(C 2 H 5 ) 2 .(CO) 2 + H 8 = CO.O + N CO.(CH 5 ) 2 .m 
 
 2 mol. cyanic ether. Diethylcarbamide. 
 
 N.C 8 H 5 .CO + NH 3 = N 2 .CO.C 2 H 5 .H S . 
 
 Etliylcarbamide. 
 II. Dialkalamides. 
 
 There are no primary dialkalamides : but there exists a class of compounds occupy- 
 ing ail intermediate place between primary and secondary dialkalamides. They re- 
 present 2 mols. of ammonia, in which 3 atoms of hydrogen are replaced, 2 by a diatomic 
 acid-radicle, and 1 by a monatomic base-radicle. With the exception of phenyl-oxamide, 
 N 2 .C 6 H 5 .C 2 0-.H 3 , the only members of this class are the compound ureas, representing 
 urea or carbamide in which 1 H is replaced by a base-radicle : 
 
 Ethyl-carbamide (ethyl-urea) .... N 2 .(CO)".C 2 H 5 .H 3 
 Phenyl-carbamide (phenyl-urea) .... ^.(COy'.OIP.H 3 . 
 
 They are formed by the action of a primary amine on cyanic acid, or of ammonia on 
 
 cyanic ethers : 
 
 N.C 2 H 5 .H 2 + KCO.H = N 2 .CO.C 2 H 5 .H 3 
 NH 3 + N.CO.C 2 H 5 = N 2 .CO.C 9 H 5 .H 3 
 
 They are decomposed by potash, yielding carbonate, a primary amine and ammonia : 
 N 2 .CO.C 6 H 5 .H 3 + H 2 .K 2 .0 2 = CO.K 2 .0 2 + N.C 6 H 5 .H 2 + NH 3 . 
 
 2. Secondary Dialkalamides. They represent 2 molecules of ammonia in which 
 4 atoms of hydrogen are replaced by 2 monatomic base-radicles and 1 diatomic acid 
 radicle : 
 
 Dimethyloxamide N 2 .(CII 3 ) 2 .(C 2 2 )".H 2 
 
 Diphenylsuccinamide N 2 .(C (J H 5 ) 2 .(C 2 H 4 2 )..H 8 
 
 Diethylcarbamide (diethyl-urea) .... N 2 .(C 2 H 5 ) 2 .(CO)".H 2 
 
ALKALAMIDES. 181 
 
 They are formed: 
 
 1. By heating the normal salts of organic alkalis : 
 
 C 2 4 (N.CH 3 .H 3 ) 2 - 2H 2 = N 2 .(CH 3 ) 2 .C 2 2 .H 2 
 
 Oxalate of iriethy- Dimethyloxamide. 
 
 Hum. 
 
 2. By action of primary amines on ethers of dibasic acids : 
 
 C 2 2 .(C 2 H 5 ) 2 .0 2 - N 2 .(CH 3 ) 2 .H 4 = (C 2 H 5 ) 2 .H 2 .0 2 + N 2 .(CH 3 ) 2 .C 2 2 .H 2 . 
 
 Oxalate of ethyl. 2 mol. methyl- 2 inoi. alcohol. Dimethyloxamide. 
 
 amiue. 
 
 3. By action of primary amines on chlorides of acid-radicles : 
 
 N 2 .(C 6 H 5 ) 2 .H 2 .H 2 + CO.C1 2 = 2HC1 + N 2 .(C 6 H S ) 2 .CO.H 2 . 
 
 2 mol. phenylamine. Chloride Diphenylcarbamide. 
 
 of carbonyl. 
 
 The compound ureas (alkal-carbamides) belonging to this group are also formed by 
 the action of water on cyanic ethers : 
 
 2(N.CO.C 2 H 5 ) + H 2 = CO.O + N 2 .(C 2 H 5 ) 2 .CO.H 2 . 
 
 Cyanateof Diethylcarbamide. 
 
 ethyl. 
 
 All these secondary dialkalamides are decomposed by potash, yielding a primary 
 amine, and the normal potassium-salt of their acid : 
 
 N 2 .(C 2 H 5 ) S .C 2 2 .H 2 + H 2 K 2 2 = N 2 .(C 2 H 5 ) 2 .H 4 -t- C 2 2 K 2 .0 2 
 
 Diethyloxamide. 2 mols. ethyl- Oxalate 
 
 amine. potass. 
 
 Hofmann regards melaniline, C 13 H 13 N 3 , and a compound, C 19 H 17 N 3 , which he has ob- 
 tained by the action of dichloride of carbon on phenylamine, as cyan-diphenyldiamide, 
 N 2 .CN.(C 6 H 5 ) 2 .H 3 , and cyantriphenyldiamide, N-.CN.(C 6 H 5 ) 3 .H 2 , respectively,*, e. as 
 dialkalamides containing only monatomic radicles. Considering the reaction by which 
 the latter at least of these compounds is formed, it may perhaps be preferable to regard 
 it as deriving from 3 molecules of ammonia, in which a portion of the hydrogen is 
 replaced by the tetratomic radicle, C"" viz. as N 3 .C.(C 6 H 5 ) 3 .H 2 . 
 
 Pebal has described the following compounds, intermediate between secondary and 
 tertiary dialkalamides : 
 
 Diphenylcitrimide N 2 .(C 6 H 5 ) 2 .(C B H 5 4 )'".IT 
 
 Diphenylaconitimide N 3 .(C 6 H 5 ) 2 .(C 6 H 3 3 )'".H. 
 
 They correspond to the monacid phenylium-salts of tribasic acids, less the elements 
 of 3 atoms of water : 
 
 C 6 H 5 7 (N.C 6 H 5 .H 3 ) 2 H - 3H 2 - N 2 .(C S H 5 ) 2 .C 6 H 5 4 .H. 
 
 3. Tertiary Dialkalamides. They represent 2 molecules of ammonia in which 
 all the hydrogen is replaced by base- and acid-radicles, one of which at least must be 
 polyatomic. This process is represented by compound-ureas, in which all the hydro- 
 gen is replaced by basic radicles, e.g. Tetrethylcarbamide or tetrethyl-urea, 
 N 2 .(CO)".(C 2 H 5 ) 4 . Also by Buff's sulphocyanide of ethyleue (efaylene-disulphocarbamide) 
 N 2 .(CS) 2 .(C 2 H 4 )". obtained by boiling chloride of ethylene with an alcoholic solution of 
 sulphocyanate of potassium (Proc. Eoy. Soc. viii. 188), and by Hofmann' s diphenyl- 
 carboxamide, N 2 .(CO)".(C 2 2 )(C 6 H 5 ) 2 ", obtained by the action of dilute hydrochloric 
 acid on dicyanmelaniline. 
 
 C 15 H 13 N + 3HC1 + 3H 2 . 3NH 4 C1 + N 2 .CO.C 2 2 .(C 6 H 5 ) 2 
 
 More might probably be obtained by the action of secondary amines on chlorides of 
 acid radicles, or on ethers of dibasic acids : 
 
 2(N.(CH 3 ) 2 .H) + C 4 H 4 3 .C1 2 - 2HC1 + N 2 .(CH 3 ) 4 .C 4 H 4 2 . 
 
 Tetramethylsucci- 
 namide. 
 
 2[K(C 2 H 5 ) 2 .H] + C 4 H 4 2 .(C 2 H 5 ) 2 .0 2 = 2(C 2 H 5 .H.O) + N 2 .(C 2 H 5 ) 4 .C 4 H 2 3 
 
 Succinate of ethyl. Tetrethylsuccinamide. 
 
 III. Trialkalamides. 
 
 1. Secondary Trialkal amides. They correspond to 3 molecules of ammonia, in 
 which 6 atoms of hydrogen are replaced by 1 triatomic acid-radicle and 3 monatomic 
 base-radicles. Examples are Pebal's triphenylcitramide, N 3 .(C 6 H 5 ) 3 .(C H H 5 4 )'".H 3 , ob- 
 tiiined by the action of citric acid on phenylamine : 
 
 C 6 H 5 4 .H 3 .0 3 + 3(N.CH\H 2 ) = N 3 .(C 6 H 5 ) 3 .C 6 H 5 4 .H 3 + 3H 2 
 
 It corresponds to the normal citrate of phenylium, less the elements of 3 atoms of 
 water. Also Schiff' s triphenylphosphamide, N 3 .(C 6 H 6 ) 3 .PO.H 3 , and trinaphtylphos- 
 
 N 3 
 
132 AMMONIA. 
 
 phamide, N 3 .(C )0 H 7 ) 3 .PO.H 3 , obtained by the action of phenylamine and naphtylamine 
 respectively on oxychloride of phosphorus (Ann. Ch. Pharm. ci. 300) : 
 
 POC1 3 + 3(N.C 6 H 5 .H 2 ) = N 3 .(C 6 H 5 ) 3 .PO.H 3 . + 3HC1. 
 
 2. Tertiary Trialkalamides. The cyanuric ethers maybe placed in this divi- 
 sion, e. g. cyanurate of ethyl, N 3 .(CO) 3 .(C 2 H 5 ) 8 . F. T. C. 
 
 ATVnVEEIiXDE and AaXMEXiXNTE. See CYANTJKAMIC ACIDS. 
 
 .aittMIOiXTE. A red earthy mass from Chile, containing 36'5 antimony, 14'8 
 tellurium, 12'2 copper, 22'2 mercury, and 2'5 quartz, besides oxygen; probably a 
 mixture. (Eammelsberg 's Mineralchemie, p. 426.) 
 
 /LIvnvEONIA. NH 3 . (Synonymes, Volatile alkali, Alkaline air, Ammoniacal gas, 
 Ammoniaque, Ammoniak.) 
 
 History. The earliest mention of aqueous ammonia, which was known long before 
 the gas itself, is made by Eaymond Lully, in the thirteenth century : he prepared it 
 from urine, and called it Mercurius vel spiritus animalis. Basil Valentine, in the 
 fifteenth century, first prepared it from sal-ammoniac : he still retained the name spiritus 
 urines. It was Bergman (1782) who first designated it by the name ammonia. Am- 
 moniacal gas was discovered by Priestley, who describes it in 1774 by the name of 
 alkaline air ; he also observed its decomposition by the electric spark. Scheele, in 1777, 
 ascertained that it contained nitrogen, regarding it as a compound of nitrogen and 
 phlogiston. Its true composition was first ascertained by Berthollet (1785) ; and it 
 was finally analysed with still greater exactness, by his son Am. Berthollet in 1808. 
 
 Natural Sources. Ammonia exists in the air as carbonate of ammonium : in rain- 
 water, especially in that of thunder-showers, as nitrate. In sea-water, and in many 
 mineral springs. In most kinds of clay and soils : in sesquioxide of iron, and in the 
 majority of iron-ores. Sal-ammoniac and ammonium-alum are found as minerals, the 
 former chiefly in volcanic regions, and in some specimens of rock-salt. As ammoniacal- 
 salts, in animal fluids and excrements (especially in mine), and in the juices of many 
 plante. 
 
 Formation. Ammonia cannot be formed by the direct combination of its elements 
 in the free state. When 1 vol. nitrogen and 3 vols. hydrogen are passed through a 
 red-hot tube, no ammonia is formed, not even if spongy platinum be present. But it 
 is formed with great readiness by the combination of its elements, when one or both 
 of them is in the nascent state : i. e. at the moment of its liberation from another 
 compound : and in this manner ammonia may be formed from many substances, organic 
 and inorganic. 
 
 1. From inorganic substances. On igniting a mixture of oxygen, nitrogen, and 
 excess of hydrogen, nitrate of ammonium is formed. (Th. Saussure.) 
 
 a. Formation from nascent hydrogen and free nitrogen. Water containing at- 
 mospheric air yields nitric acid at the positive pole, and ammonia at the negate pole 
 of a voltaic battery (Sir H. Davy). Moistened iron-filings, in contact with atmo- 
 spheric air or nitrogen at the ordinary temperature, induce the formation of ammonia 
 (Chevallier, Berzelius). (Will states that no ammonia is thus formed.) This 
 reaction accounts for the existence of ammonia in rust of iron, and iron ores generally. 
 When liver of sulphur is fused with an equal weight of iron-filings, and water dropped 
 on the hot mass, ammonia is evolved (Hollunder). When certain metals which 
 combine readily with oxygen (potassium, arsenic, lead, iron, &c.) are heated with the 
 hydrates of potassium, sodium, barium, or calcium, in contact with air, ammonia is 
 formed. Faraday states that this formation of ammonia takes place even in an atmo- 
 sphere of hydrogen : a fact explained by Bischof as arising from the difficulty of 
 obtaining hydrogen free from atmospheric air. Eeiset also points out that the hydrogen 
 will contain nitric oxide, if the sulphuric acid employed for its generation contains 
 nitric acid or nitric oxide. 
 
 b. Formation from nascent nitrogen and free hydrogen. A mixture of 2 vols. nitric 
 oxide and 5 vols. hydrogen passed over gently heated spongy platinum, yields ammonia 
 and water (Hare; Ville, Ann. Ch. Phys. [3] xlvi) The same gases when passed 
 through a red-hot tube, only yield ammonia when some porous substance is present ; 
 pumice-stone, or ferric oxide acts most energetically (Reiset). Nitrous oxide and 
 hydrogen in excess yield ammonia when in contact with hot spongy platinum or plati- 
 num-black. Hydrogen saturated with nitric acid vapour acts in a similar manner. 
 
 c. Formation from nascent hydrogen and nascent nitrogen. Moist nitric oxide 
 passed over heated iron-filings yields ammonia. A mixture of nitric oxide and hydro- 
 sulphuric acid, passed over heated soda-lime, yields ammonia (Ville). Certain 
 metals which decompose water at a high temperature (iron, zinc, &c.), when treated 
 with dilute nitric acid, or the aqueous solutions of certain nitrates, yield ammonia. 
 Ammonia is formed when nitric acid is added to zinc and sulphuric acid in a hydrogen 
 
AMMONIA. 183 
 
 apparatus, also by the decomposition of chloride, iodide, and phosphide of nitrogen, 
 and of all bodies belonging to the class, amides, by water. When a mixture of baryta 
 and carbonaceous matter is heated in contact with air, cyanide of barium is formed, a 
 compound which is decomposed by steam at 300 C. into carbonate of barium and 
 ammonia : Margueritte and Sourdeval have lately proposed to employ this process for 
 the preparation of ammonia on the large scale. (Rep. Chim. App. ii. 170.) 
 
 2. From organic substances. Many non-nitrogenous organic bodies form ammonia 
 by prolonged contact with air and water : e. g. in the process of putrefaction. Sugar, 
 oxalates, tartrates, &c. yield ammonia when heated with alkaline or alkaline-earthy 
 hydrates, in contact with air. Oxygen-compounds of nitrogen, heated with organic 
 reducing agents, e.g. nitric oxide with alcohol- vapour, nitric acid with gum, form 
 ammonia. Most mtrogenised organic compounds yield ammonia, either free or com- 
 bined, in the processes of putrefaction or of dry distillation : it is from this source that 
 the ammonia existing in nature is chiefly derived. 
 
 Preparation. Powdered sal-ammoniac is mixed with twice its weight of slaked lime, 
 the mixture covered with a layer of coarsely powdered quick lime, about equal in weight 
 to the sal-ammoniac used, and the whole heated gradually in a flask or retort : for the 
 preparation of ammonia on a large scale, iron vessels are used. The gas is passed 
 through a two-necked bottle, in which aqueous vapour is condensed, and any solid 
 particles that may be carried over are arrested ; it is then dried by passing over solid 
 potash or quick lime or better, a mixture of the anhydrous oxides of potassium and 
 copper, obtained by heating nitrate of potassium with finely divided copper reduced 
 from the oxide by hydrogen (Stas), (chloride of calcium absorbs the gas) and collected 
 over mercury. If the gas is pure, it should be entirely absorbed by water. In order 
 to obtain perfectly dry ammonia, Vogel recommends saturating a concentrated aqueous 
 solution of ammonia with solid chloride of calcium, heating gently, and passing the 
 gas over solid potash. 
 
 Properties. Colourless gas, of a pungent smell, and strong alkaline taste. Its 
 specific gravity is (calculated) 0-5893 ; (H.Davy) 0'5901; (Thomson) 0-5931; (Biot 
 and Arago) 0'5967. 1 litre at C. and 760mm. barometric pressure weighs 0'7752 
 grm. (Biot and Arago). Its specific heat (water = 1) is 0*508 (Eegnault). Its 
 refractive power (air = 1) is 1*309 (Dulong). 
 
 It does not support either combustion or respiration : animals die when immersed 
 in it. It is feebly combustible : when issuing in a thin stream into atmospheric air, 
 it may be kindled, and burns with a pale flame. It colours turmeric paper brown, 
 and reddened litmus blue : the colours disappear on exposure to the air. 
 
 It may be condensed by cold and pressure, and obtained both in the liquid and solid 
 form. Faraday prepares liquid ammonia as follows : Ammonio-chloride of silver is 
 introduced into a very strong glass tube, closed at one end, which is then bent at an 
 acute angle, the chloride being in the longer limb. The shorter limb is then sealed 
 and immersed in ice, and the chloride gradually heated : it fuses at 38 C., and be- 
 tween 112 and 119 C. gives off all its ammonia, which condenses to a liquid by its 
 own pressure in the cool part of the tube. As the chloride of silver cools, the liquid 
 ammonia boils violently, and is reabsorbed by the chloride. Guy ton de Morveau and 
 Bunsen have condensed ammonia without pressure by a mixture of chloride of calcium 
 and ice, the former at 52 C., the latter at 40. Liquid ammonia is a colourless, very 
 mobile liquid, refracting light more powerfully than water; specific gravity 0*76: 
 boiling-point at 749mm. barometic pressure, 33*7 C. (Bunsen.) Its tension at 
 -1778 C. = 2-48 atmospheres: at C. = 4*44 atm. : at 10'8 C. = 6 atm. : at 
 19-44 C. = 7-60 atm.: at 28-31 C. = 10 atm. 
 
 Faraday has obtained solid ammonia by exposing the dry gas to a pressure of 20 
 atmospheres and to a cold of 75 C., produced by solid carbonic anhydride and ether. 
 It is a white, transparent, crystalline body, which melts at 75 C., and has a higher 
 specific gravity than liquid ammonia. 
 
 Decompositions. Dry ammonia is decomposed by a succession of electric sparks : 
 the resulting gas is double the volume of the original gas, and consists of 1 vol. nitroge;: 
 and 3 vols. hydrogen. Also by being passed through a red-hot porcelain tube contain- 
 ing copper or iron wire; gold-, silver-, or platinum- wire acts similarly, but less ener- 
 getically. No change is produced in the gold and platinum-wire : the copper and iron 
 wire are rendered brittle, and sometimes increased in weight, owing to the formation 
 of a nitride. 2 vols. ammonia mixed with not less than 1, nor more than 6 vols. 
 oxygen, are exploded by the electric spark : the products, if the oxygen be in excess, 
 are water and nitrate of ammonium ; if the ammonia be in excess, water, nitrogen, 
 and hydrogen, Aqueous ammonia, in contact with finely divided copper or platinum, 
 and oxygen or atmospheric air, is converted into nitrite of ammonium, both its con- 
 stituents undergoing oxidation (Handwb.j Ammonia is decomposed by several of the 
 oxygen-compounds of chlorine and nitrogen. Dry ammonia mixed with dry hypo- 
 's 4 
 
184 AMMONIA. 
 
 chlorous anhydride explodes violently at the ordinary temperature, with separation of 
 chlorine. Aqueous ammonia added gradually to aqueous hypochlorous acid, the 
 mixture being kept cool, yields nitrogen, and chloride of nitrogen. Ammonia mixed 
 with proper proportions of nitrous or nitric oxide, explodes by the electric spark, yield- 
 ing water and nitrogen. Ammonia is violently decomposed at the ordinary temperature 
 by peroxide of nitrogen, whether liquid or gaseous, with evolution of nitric oxide and 
 nitrogen (Dulong). In contact with chlorine in the cold, ammonia burns with a red 
 and white flame, forming chloride of ammonium and free nitrogen (4NH 3 + Cl 3 = 
 3NH 4 C1 + N) ; when chlorine is passed into strong aqueous ammonia or a solution of an 
 ammoniacal-salt, chloride of nitrogen is also formed. Iodine does not decompose 
 dry ammonia : in presence of water, iodide of ammonium and an iodine-deriva- 
 tive of ammonia are formed. With bromine, ammonia yields bromide of ammo- 
 nium and free nitrogen. Passed with vapour of phosphorus through a red-hot tube, 
 ammonia yields phosphide of hydrogen and free nitrogen. Passed over red-hot char- 
 coal, ammonia yields cyanide of ammonium and free hydrogen. With bisulphide of 
 carbon, ammonia gives hydrosulphuric and sulphocyanic acids (NH 3 + CS 2 = H'-S + 
 CSH). When potassium or sodium is heated in dry ammonia, hydrogen is evolved, 
 its place being supplied by the metal, and nitride of potassium and hydrogen (potassa- 
 mine), NKH-, is formed. In contact with zinc-ethyl, ammonia gives zinc-amine NZnH* 
 and hydride of ethyl, C 2 H 6 . Many metallic oxides decompose ammonia with the aid of 
 heat : the products are sometimes water, nitrogen, reduced metal, and more or less of 
 an oxygen-compound of nitrogen ; sometimes, water and a metallic nitride. Ammonia 
 reacts with anhydrous acids, chlorides of acid-radicles, and many compound ethers, 
 giving amio acids, or amides. In like manner, it gives with many derivatives of the 
 alcohols, amic bases or amines. (See AMIC ACIDS, AMIC BASES, AMIDES, AMINES.) 
 
 We have seen that ammonia is decomposed by certain metals and metallic oxides, 
 hydrogen being liberated, and compounds formed representing ammonia in which a 
 part or the whole of the hydrogen is replaced by a metal. There are certain organic 
 compounds (e. g. monobasic anhydrides, compound ethers, &c.) which are capable of 
 decomposing ammonia in a similar manner, with formation of compounds representing 
 ammonia in which the hydrogen is wholly or partially replaced by an organic radicle, 
 acid or basic. The numerous and interesting class of compounds which are thus 
 formed from ammonia by the partial or total replacement of its hydrogen by other 
 radicles, organic or inorganic, acid or basic, is known by the generic name of amides : 
 under which name they are fully described. 
 
 Combinations. 1. With Water (Solution of ammonia, Aqueous ammonia, or 
 simply Ammonia, Spirits of hartshorn, SalmiaJcgeist, Liquor ammonii). 
 
 Both water and ice absorb ammonia with great avidity, with considerable evolution 
 of heat, and with great expansion. Davy found that 1 vol. water at 10 C. and 29*8 
 inches barometric pressure absorbs 670 vols. ammonia, or nearly half its weight: the 
 specific gravity of this solution is 0*875. According to Dalton, water at a lower tem- 
 perature absorbs even more ammonia, and the specific gravity of the solution is 0'85. 
 According to Osann, 100 pts. water at 24 C. absorb 8'41 pts. at 55 C. 5'96 pts. am- 
 monia. 1 vol. water by absorbing 505 vols. ammonia, forms a solution occupying 
 1-5 vols., and having specific gravity 0'9 : this, when mixed with an equal bulk of 
 water, yields a liquid of specific gravity G'9455 : whence it appears that aqueous 
 ammonia expands on dilution. (Ure.) 
 
 Preparation. 1 part of sal-ammoniac in lumps is introduced into a glass flask, 
 with 11 parts slaked lime, and from 1 to 11 parts water : and the^flask is connected 
 by bent tubes with three Woulfe's bottles. The first bottle, which is intended to 
 arrest any solid particles that may be carried over mechanically, and any empyreu- 
 matic oil contained in the sal-ammoniac, as well as to condense aqueous vapour, con- 
 tains a small quantity of water (Mohr prefers milk of lime). The second bottle con- 
 tains the water to be saturated with ammonia : it should contain a quantity of water 
 about equal in weight to the sal-ammoniac employed, and should not be more than 
 three parts full, to allow for the expansion. These two bottles should be placed in cold 
 water, and each provided with a safety tube. The third bottle contains a little water, 
 to retain any ammonia that may pass through the second bottle. The flask is then 
 heated in a sand-bath, care being taken that its contents do not boil over : and the 
 operation continued till about half the water in the flask has distilled over into the first 
 bottle. The first bottle then contains a weak and impure solution of ammonia : the 
 second a pure and strong solution (if a perfectly saturated solution be required, the 
 quantity of water in this bottle should not exceed the weight of the sal-ammoniac 
 employed) : the solution in the third bottle is weak, but pure. 
 
 The proportions of lime and water to be added to the sal-ammoniac in order to pro- 
 duce the largest yield of ammonia have been variously stated : those given above are 
 
AMMONIA. 
 
 185 
 
 now most generally received. According to the equation, CaHO + NH 4 C1 = Nil 3 + 
 CaCl + IPO, the amount of slaked lime should be to that of sal-ammoniac as 
 37 : 53-5, or 69 parts of the former to 100 parts of the latter. But in practice it is 
 always found necessary to employ a larger proportion of lime ; for not only is the lime 
 of commerce always impure, but also it is impossible to bring the whole of it into such 
 contact with the sal-ammoniac, as woxild ensure the completeness of their reaction. 
 The object of adding water is to ensure the gradual solution of the sal-ammoniac, and 
 consequently its more complete contact with the lime. There are also other disad- 
 vantages which attend the absence of water. If the lime and sal-ammoniac are mixed 
 in a state of powder, a large quantity of ammonia is lost before the mixture is intro- 
 duced into the flask ; and the heated mass expands on cooling so as invariably to 
 break the flask. These inconveniences are avoided by first placing the sal-ammoniac 
 in lumps in the flask, and then covering it with the powdered lime : but in this case 
 the heat required is sufficient to volatilise the sal-ammoniac, which is liable to stop 
 up the delivery-tube and cause a dangerous explosion. Moreover a larger quantity 
 of empyreumatic oil passes over with the ammonia : and the chloride of calcium formed 
 in the flask obstinately retains a portion of the ammonia, which is consequently lost. 
 On the other hand, the addition of too much water diminishes the pi-oduct of am- 
 monia, and hampers the operation in other ways. 
 
 In the preparation of aqueous ammonia on a large scale, the gas is generated in 
 cast-iron or copper vessels : earthenware vessels are generally found not to answer, 
 owing to the porosity of their structure. 
 
 The aqueous ammonia thus prepared may contain the following impurities, which 
 are easily detected^: 
 
 Carbonate of ammonium. Occurs when the lime employed contains much carbonate, 
 or when the solution has been exposed to the air. Causes turbidity when heated with 
 chloride of barium. 
 
 Chlorine. Owing to chloride of ammonium having been sublimed, or carried over 
 mechanically. The solution, saturated with nitric acid, gives a cloudiness with nitrate 
 of silver. 
 
 Lime. Carried over mechanically. Gives a precipitate with oxalic acid : left as a 
 solid residue on evaporation. 
 
 Copper or Lead. Derived from the generating vessel. The former is detected by the 
 solution becoming tinged with blue on evaporation ; the latter by hydrosulphuric acid. 
 
 Empyreumatic oil. From the sal-ammoniac. The solution has a yellow colour 
 and a peculiar smell. 
 
 Properties. Aqueous ammonia is a colourless transparent liquid, smelling of 
 ammonia, and having a sharp burning, urinous taste. Its specific gravity varies from 
 1-000 to 0'85, according to the amount of ammonia it contains: its boiling-point varies 
 similarly (see D alt on ' s table, infra.} A perfectly saturated solution freezes between 
 38 and 41 C., forming shining flexible needles: at - 49 C. it solidifies to a 
 grey gelatinous mass, almost without smell (Fourcroy and Vauquelin). It loses 
 almost all its ammonia at a temperature below 100 C. The following tables have 
 been constructed, showing the amount of real ammonia contained in aqueous ammonia 
 of different densities : 
 
 DALTON. 
 
 H. DAVY. 
 
 UHE. 
 
 Specific- 
 gravity. 
 
 Percentage 
 Ammonia. 
 
 Boiling 
 Point 
 
 Specific 
 gravity. 
 
 Percentage 
 Ammonia. 
 
 Specific 
 gravity. 
 
 Percentage 
 Ammonia. 
 
 Specific 
 gravity. 
 
 Percentage 
 Ammonia. 
 
 0-85 
 
 353 
 
 -4 
 
 0-8750 
 
 32-3* 
 
 0-8914 
 
 27-940 
 
 0-9363 
 
 15-900 
 
 086 
 
 326 
 
 +3-5 
 
 8857 
 
 29-25 
 
 0-8937 
 
 27-633 
 
 09410 
 
 14-575 
 
 0-87 
 
 29-9 
 
 10 
 
 0-9. oo 
 
 26'00 
 
 G'8967 
 
 27-038 
 
 0-9455 
 
 13-250 
 
 0-.S8 
 
 27-3 
 
 17 
 
 0-9054 
 
 25-37* 
 
 0*S9>i3 
 
 26-751 
 
 0-9510 
 
 11-925 
 
 0-89 
 
 24-7 
 
 23 
 
 0-9166 
 
 2207 
 
 9000 
 
 2G-.VO 
 
 0-9564 
 
 10'600 
 
 0*90 
 
 22-2 
 
 30 
 
 9255 
 
 19-4 
 
 9045 
 
 '5-175 
 
 09614 
 
 9 275 
 
 0-91 
 
 19 8 
 
 37 
 
 0-9326 
 
 17-52 
 
 0-9090 
 
 23-S50 
 
 
 7*950 
 
 0-92 
 
 17-4 
 
 44 
 
 0-0385 
 
 15-88 
 
 0-9133 
 
 22-525 
 
 0-9716 
 
 6-625 
 
 0-93 
 
 16-1 
 
 50 
 
 0-9435 
 
 14 53 
 
 0-9177 
 
 21 200 
 
 0-9768 
 
 
 (i 91 
 
 12-8 
 
 57 
 
 0-9476 
 
 13-46 
 
 0-9227 
 
 19-875 
 
 0-<i82H 
 
 3-975 
 
 (i :,) 
 
 10-5 
 
 63 
 
 0-9513 
 
 1 2-40 
 
 0*9V7A 
 
 18 550 
 
 0-!<8H7 
 
 2 650 
 
 09G 
 
 83 
 
 70 
 
 0-954(5 
 
 11-56 
 
 0-9320 
 
 1 7 "'*'") 
 
 9945 
 
 1-325 
 
 0-97 
 
 6-2 
 
 79 
 
 0-9573 
 
 10-82 
 
 
 
 
 
 ' 9S 
 
 4-1 
 
 87 
 
 0-9597 
 
 10-17 
 
 
 
 
 
 099 
 
 2-0 
 
 92 
 
 0-9616 
 
 9 60 
 
 
 
 
 
 
 
 
 0-9692 
 
 9 50* 
 
 
 
 
 
 * Those numbers were determined by experiment : the rest in Davy's table by calculation. 
 
186 
 
 AMMONIA. 
 
 J. OTTO. Determinations made at 16 C. 
 
 Specific 
 gravity. 
 
 Percentage 
 Ammonia. ' 
 
 Specific 
 gravity. 
 
 Percentage 
 Ammonia. 
 
 Specific 
 gravity. 
 
 Percentage 
 
 Ammonia. 
 
 0-9517 
 
 12-000 
 
 0-9607 
 
 9-625 
 
 09697 
 
 7'250 
 
 0-9521 
 
 11-875 
 
 0-9612 
 
 9-500 
 
 0-9702 
 
 7' 1 25 
 
 0-9526 
 
 11-750 
 
 0-9616 
 
 9-375 
 
 0-9707 
 
 7-000 
 
 0-9631 
 
 11-625 
 
 0-9621 
 
 9-250 
 
 0-9711 
 
 6-87-i 
 
 0-9536 
 
 11-500 
 
 0-9626 
 
 9-125 
 
 0-9716 
 
 6-750 
 
 0-9540 
 
 11-375 
 
 0-!)<;:51 
 
 4-000 
 
 0-9721 
 
 6-6M 
 
 0-9545 
 
 11-250 
 
 0-96S6 
 
 8-875 
 
 0-9726 
 
 6500 
 
 09550 
 
 11-125 
 
 0-9641 
 
 8-750 
 
 0-9730 
 
 6-375 
 
 0-9555 
 
 11-000 
 
 0-9(i45 
 
 8- '125 
 
 0-9735 
 
 6-250 
 
 0-9556 
 
 10-950 
 
 0-<J650 
 
 8-500 
 
 0-9740 
 
 6-125 
 
 9559 
 
 10-875 
 
 0-9654 
 
 8-375 
 
 0-9745 
 
 6000 
 
 0-9564 
 
 10750 
 
 0-9059 
 
 8-250 
 
 0-9749 
 
 5-875 
 
 0-9569 
 
 10625 
 
 0-9664 
 
 8-125 
 
 C'9754 
 
 5750 
 
 0-9574 
 
 JO-.iOO 
 
 0-9669 
 
 8-000 
 
 0-9759 
 
 5-625 
 
 0-9.S78 
 
 10-375 
 
 09673 
 
 7-875 
 
 0-9764 
 
 5-500 
 
 09583 
 
 10-250 
 
 09078 
 
 7-750 
 
 0-9768 
 
 5-375 
 
 09588 
 
 10-1 '25 
 
 0-968M 
 
 7-625 
 
 0-9773 
 
 5-250 
 
 0-9593 
 
 10-000 
 
 0-9(588 
 
 7-500 
 
 0-9778 
 
 5-125 
 
 C'9597 
 
 9-875 
 
 0-9692 
 
 7-375 
 
 09783 
 
 5-000 
 
 0-9602 
 
 9-750 
 
 
 
 
 
 L. CAKIUS. (Ann. Ch. Pharm. xcix. 164.) Determinations made at 14 C. 
 
 Specific 
 gravity. 
 
 P. C. 
 
 Amm. 
 
 Specific 
 gravi-y. 
 
 P. C. 
 An m. 
 
 Specific 
 gi-avity. 
 
 P. C. 
 
 Amm. 
 
 Specific 
 r.ravity. 
 
 P. C. 
 
 Amm 
 
 Specific 
 gravity. 
 
 P. C. 
 
 Amm. 
 
 Specific 
 gravity. 
 
 P. C. 
 
 Amm. 
 
 0-8*44 
 
 36-0 
 
 0-8976 
 
 30-0 
 
 0-9133 
 
 24-0 
 
 0-9314 
 
 18-0 
 
 0-9520 
 
 12-0 
 
 0-9749 
 
 6-0 
 
 0-8848 
 
 35-8 
 
 0-H9H1 
 
 29-8 
 
 0-9139 
 
 2.5-8 
 
 0-9321 
 
 17-8 
 
 09527 
 
 11-8 
 
 0-9757 
 
 5-8 
 
 0-88.')2 
 
 356 
 
 08986 
 
 29-6 
 
 0-9145 
 
 2:5-0 
 
 0-9327 
 
 17-6 
 
 0-9534 
 
 11-6 
 
 0-W5 
 
 5-0 
 
 0-8X56 
 
 35-4 
 
 08991 
 
 29-4 
 
 0-9150 
 
 23-4 
 
 0-93:i3 
 
 174 
 
 9542 
 
 11-4 
 
 0-977--5 
 
 5-4 
 
 08860 
 
 3o 2 
 
 8>i96 
 
 29-2 
 
 0-9156 
 
 2.52 
 
 0-9340 
 
 17'2 
 
 0-9549 
 
 11-2 
 
 0-9781 
 
 5"2 
 
 0-8804 
 
 35-0 
 
 0-9f)()l 
 
 29 
 
 0-9162 
 
 23-0 
 
 0-9317 
 
 17'0 
 
 0-9556 
 
 11 
 
 0-9790 
 
 5-0 
 
 08*68 
 
 34-8 
 
 0-9006 
 
 28-8 
 
 0-9168 
 
 2*2" 8 
 
 0-9353 
 
 16-8 
 
 9o63 
 
 10-8 
 
 0-9799 
 
 4-8 
 
 0-8K72 
 
 346 
 
 0-9011 
 
 28-6 
 
 0-9174 
 
 22-6 
 
 0-9360 
 
 16-6 
 
 0-9571 
 
 10-6 
 
 0-9807 
 
 4-6 
 
 0-8877 
 
 34-4 
 
 0-9016 
 
 28-4 
 
 0-9180 
 
 22-4 
 
 0-9:500 
 
 16-4 
 
 0-S.V8 
 
 10-4 
 
 0-9815 
 
 4-4 
 
 0-8881 
 
 34*2 
 
 0-9021 
 
 28-2 
 
 0-9185 
 
 222 
 
 0-9373 
 
 16-2 
 
 0-9586 
 
 102 
 
 0-9823 
 
 4-2 
 
 0-8885 
 
 340 
 
 09026 
 
 28-0 
 
 0-9191 
 
 22-0 
 
 0-9380 
 
 16-0 
 
 0-9503 
 
 10-0 
 
 9:5i 
 
 4-0 
 
 0-88s9 
 
 33-8 
 
 0-9031 
 
 27-8 
 
 0-9197 
 
 218 
 
 09386 
 
 158 
 
 0-9601 
 
 9-8 
 
 0-9839 
 
 3-8 
 
 08*94 
 
 336 
 
 0-9036 
 
 27-6 
 
 0-9203 
 
 21-6 
 
 0-9393 
 
 15-6 
 
 9008 
 
 9-6 
 
 09847 
 
 3-6 
 
 0' 98 
 
 334 
 
 0-9041 
 
 27-4 
 
 0-9209 
 
 21-4 
 
 0-9400 
 
 15-4 
 
 0-9616 
 
 9-4 
 
 O-qHflS 
 
 3-4 
 
 0-8903 
 
 33-2 
 
 0-!)047 
 
 272 
 
 0-9215 
 
 21-2 
 
 0-9407 
 
 15-2 
 
 09623 
 
 9-2 
 
 0-9863 
 
 3-2 
 
 0-8907 
 
 33-0 
 
 0-9052 
 
 27-0 
 
 0-9221 
 
 21-0 
 
 0-9414 
 
 15-0 
 
 0-9031 
 
 9-0 
 
 0-98'3 
 
 3-0 
 
 0-8911 
 
 328 
 
 0-90-7 
 
 26-8 
 
 0-9227 
 
 20-8 
 
 0-9420 
 
 14-8 
 
 0-9639 
 
 8-8 
 
 09882 
 
 2-8 
 
 0-8916 
 
 326 
 
 ()-90f,3 
 
 26-6 
 
 9233 
 
 20-6 
 
 0-9427 
 
 146 
 
 0-9647 
 
 8-6 
 
 0-9890 
 
 2-6 
 
 O'*920 
 
 32-4 
 
 0-906H 
 
 20-4 
 
 0-9239 
 
 20 4 
 
 0-9434 
 
 14-4 
 
 0-9654 
 
 8-4 
 
 0-9S99 
 
 2-4 
 
 08925 
 
 322 
 
 0-9073 
 
 26-2 
 
 0-924.T 
 
 20-2 
 
 0-9411 
 
 14 2 
 
 0-9002 
 
 8-2 
 
 0-9907 
 
 2-2 
 
 0-8929 
 
 320 
 
 0-9078 
 
 26-0 
 
 0-9251 
 
 2-.-0 
 
 0-9449 
 
 14-0 
 
 09670 
 
 8-0 
 
 0-9915 
 
 2-0 
 
 0-8931 
 
 31-8 
 
 0-9083 
 
 25-8 
 
 0-9257 
 
 19-8 
 
 0-9456 
 
 13-8 
 
 0-9677 
 
 7-8 
 
 0-9924 
 
 18 
 
 0-8938 31-6 
 
 0-<)089 
 
 25-6 
 
 0-<>2G4 
 
 196 
 
 09403 
 
 13-6 
 
 0-9685 
 
 7-6 
 
 0-9932 
 
 1-6 
 
 08943 31-4 
 
 09094 
 
 25-4 
 
 0'9'27 1 
 
 19-4 
 
 0-9470 
 
 134 
 
 0-9 93 
 
 7-4 
 
 0-9941 
 
 1-4 
 
 0-8948 31-2 
 
 O'tlOO 
 
 25-2 
 
 09277 
 
 19-2 
 
 0-9477 
 
 1:5-2 
 
 0-9701 
 
 7'2 
 
 0-9950 
 
 1-2 
 
 08953 31-0 
 
 0-9106 
 
 25 
 
 92*3 
 
 19-0 
 
 09484 
 
 13-0 
 
 0-9709 
 
 70 
 
 0-9959 
 
 1 
 
 0-8957 ' 30-8 
 
 09111 
 
 24-8 
 
 0-929 
 
 1S-8 
 
 09191 
 
 128 
 
 0-9717 
 
 6-8 
 
 9907 
 
 0-8 
 
 8<02 30'6 
 
 0-9116 
 
 24-6 
 
 0-9290 
 
 18-0 
 
 0-9498 
 
 12-6 
 
 0-9725 
 
 6-6 
 
 0-9975 
 
 0-6 
 
 0-8967 304 
 
 0-9122 
 
 24-4 
 
 0-93(W 
 
 184 
 
 9505 
 
 12-4 
 
 0-973:$ 
 
 6-4 
 
 0-99*3 
 
 0-4 
 
 0-8971 30-2 
 
 0-9127 
 
 24-2 
 
 , 0'9308 
 
 18-2 
 
 0-9512 
 
 12-2 
 
 0-9741 
 
 6-2 
 
 0-9991 
 
 0, | 
 
 By the aid of these tables, the strength of aqueous ammonia, like that of commercial 
 alcohol, may be approximately ascertained by taking its specific gravity. (See also 
 Griffin's Table given in lire's Dictionary of Arts, Manufactures, and Mines, vol. i. 
 p. 132, and Chem. Soc. Qu. J. iii. 260.) 
 
 Roscoe and Dittmar (Chem. Soc. Qu. J. xii. 147), have determined the amount of 
 ammonia-gas absorbed by water at various pressures and temperatures. The results 
 are given in the two following tables. 
 
 Table A shows the weight of ammonia-gas in grammes Cr absorbed by 1 gramme 
 of water at C. and various partial pressures P.* 
 
 * By partial pressure is meant the total pressure under which the absorption occurs, minus the tension 
 of aqueous vapour at C. 
 
AMMONIA. 
 
 187 
 
 TABLE A. 
 
 p. 
 
 G. 
 
 * P. 
 
 G. 
 
 P. 
 
 G. 
 
 P. 
 
 G. 
 
 0-00 
 
 o-ooo 
 
 25 
 
 0-465 
 
 0-85 
 
 0-937 
 
 1-45 
 
 1-469 
 
 0-01 
 
 0-044 
 
 030 
 
 0-515 
 
 090 
 
 0-968 
 
 1-50 
 
 526 
 
 0-02 
 
 0-084 
 
 0-35 
 
 0561 
 
 0-95 
 
 001 
 
 1-55 
 
 1-584 
 
 003 
 
 0-1-20 
 
 0-40 
 
 0-607 
 
 1-00 
 
 037 
 
 1-60 
 
 f>45 
 
 0-04 
 
 0-149 
 
 045 
 
 0-646 
 
 05 
 
 075 
 
 1-65 
 
 707 
 
 005 
 
 0-175 
 
 0-50 
 
 0-690 
 
 10 
 
 117 
 
 1-70 
 
 770 
 
 0-75 
 
 0-2-M 
 
 0-55 
 
 0-731 
 
 15 
 
 161 
 
 1-75 
 
 835 
 
 0-100 
 
 0-275 
 
 oc-o 
 
 0-768 
 
 20 
 
 208 
 
 180 
 
 906 
 
 0-125 
 
 0'315 
 
 0-65 
 
 0-804 
 
 25 
 
 258 
 
 1-85 
 
 976 
 
 0-150 
 
 0-351 
 
 0-70 
 
 0-840 
 
 30 
 
 310 
 
 1-90 
 
 2-046 
 
 0-175 
 
 0-382 
 
 0-75 
 
 0-872 
 
 -35 
 
 361 
 
 1-95 
 
 2-1-20 
 
 0-200 
 
 0-411 
 
 0-80 
 
 0-906 
 
 1-40 
 
 415 
 
 2-00 
 
 2-195 
 
 From these numbers it appears : (1) that the quantity of ammonia absorbed by 
 water at C. is far from being proportional to the pressure ; and (2) that for equal 
 increments of pressure up to about 1 metre of mercury, the corresponding increments 
 of absorbed ammonia continually diminish, but that above this point, the amount of 
 dissolved gas increases in a more rapid ratio than the pressure. 
 
 Table B shows the weight in grammes of ammonia (column II.), absorbed by 
 1 gramme of water under the pressure of 0'76 m . and at various temperatures (column I). 
 
 TABLE B. 
 
 '. 
 
 11. 
 
 i. 
 
 II. 
 
 I. 
 
 II. 
 
 . 
 
 11. 
 
 oc. 
 
 0-875 
 
 16 C. 
 
 0582 
 
 3'2 C. 
 
 D-ssa 
 
 48 C. 
 
 0-244 
 
 2 
 
 0-H33 
 
 18 
 
 0-554 
 
 3'1 
 
 0-31/2 
 
 5<.- 
 
 0-2-29 
 
 4 
 
 0-792 
 
 20 
 
 0526 
 
 36 
 
 0343 
 
 52 
 
 0-JI4 
 
 6 
 
 0'751 
 
 22 
 
 0-4!'<) 
 
 38 
 
 6-324 
 
 54 
 
 0-200 
 
 
 0-713 
 
 24 
 
 0-474 
 
 40 
 
 307 
 
 56 
 
 0-1 06 
 
 10 
 
 0-'J79 
 
 26 
 
 0-449 
 
 42 
 
 0--HO 
 
 
 
 12 
 
 0645 
 
 28 
 
 0-426 
 
 41 
 
 0-275 
 
 
 
 14 
 
 612 
 
 3 
 
 0-403 
 
 4(> 
 
 0-A r i9 
 
 
 
 Aqueous ammonia possesses the property of dissolving many salts which are insoluble 
 in water. Thus it dissolves chromic and stannic oxides, the protoxides of tin, cadmium, 
 zinc, &c., the oxides of copper and silver. The compounds tims formed are decomposed 
 by heat, losing ammonia, sometimes with explosive violence. Many other salts are 
 also soluble in aqueous ammonia, e. g. phosphate, chloride, bromide of silver, &c. : in 
 some cases, the original salt can be recovered unchanged by evaporating off the ammonia ; 
 in others a more intimate combination is effected. 
 
 2. With alcohol. (Liquor ammoniac! alcoholicus). 
 
 Alcohol, Like water, absorbs ammonia in great quantity, with considerable expansion 
 and evolution of heat. The alcoholic solution is prepared in precisely the same way as 
 the aqueous solution, alcohol of 85 90 p. c. being substituted for water in the second 
 bottle. The proportion of alcohol to the sal-ammoniac employed should be somewhat 
 less than in the case of water. The specific gravity of the solution of course varies 
 with the amount of alcohol and ammonia which it contains. 
 
 3. With metallic salts. Ammonia forms solid compounds with certain metallic 
 oxides (of gold, silver, platinum, mercury, antimony, &c.) which are decomposed by heat, 
 frequently with explosive violence. Certain metallic chlorides, bromides, and iodides 
 (of silver, calcium, &c.) absorb ammonia, frequently with evolution of heat. Some of 
 these compounds lose their ammonia when exposed to the air ; others, but not all, when 
 heated. Some dissolve in water without decomposition, forming solutions from which 
 the whole of the ammonia is not precipitated by dichloride -of platinum : the majority 
 are decomposed by water, which sometimes dissolves the original salt and separate's 
 ammonia, sometimes precipitates the metal as hydrate. Similarly, certain crystalline 
 salts, when freed from their water of crystallisation, absorb ammonia abundantly and 
 in atomic proportion, forming compounds which are decomposed by heat or by wat r. 
 Ammonia also combines with metallic cyanides, with fluoride of silicon, and other bodies. 
 
 4. With acids, forming ammoniacal salts. (See AMMONIACAL SALTS.) 
 
 5. With poll/basic anhydrides, forming the ammonium-salts of amic acids. (See 
 AMIC ACIDS.) p 1 . T. C. 
 
183 AMMONIAC AL SALTS. 
 
 fUtXXtXOXflTXACAXi SAXiTS. Ammonium-salts, Sets aiiirnoniacaux, Ammonidk* 
 salze. 
 
 Ammonia combines very readily with acids, which it neutralises completely, forming 
 definite crystalline salts, known by the name of ammoniacaT. or ammonium-salts. 
 These salts are isomorphous with those of potassium, and are in their general properties 
 so closely analogous to metallic salts, that they are universally regarded as belonging 
 to this class of bodies. There is, however, a characteristic difference in their mode of 
 formation. While other metallic salts are formed by the substitution of a metal for 
 the hydrogen of an acid, e.g. chloride of zinc, ZnCl = HC1 + Zn H : ammoniaoal 
 salts are formed by the direct combination of ammonia with the acid, without elimi- 
 nation of hydrogen, r.g. chloride of ammonium, NH 4 C1 = NH 3 + HC1. 
 
 Among the various theories by which it has been proposed to represent the consti- 
 tution of these salts, that which most clearly expresses their analogy with other 
 metallic salts is unquestionably the Ammonium Theory of Berzelius. According to 
 this theory, ammoniacal salts contain a compound metal, ammonium, Nil 4 , analogous 
 to potassium, sodium, and other metals, the salts of which, ammonium-salts, are 
 analogous to other metallic salts. Thus, chloride of ammonium, C1NH 4 , is analogous 
 to chloride of potassium, C1K ; sulphate of ammonium, S0 4 (NH 4 ) 2 , to sulphate of 
 potassium, S0 4 K 2 , &c. This hypothetical metal has never been isolated. An amal- 
 gam of mercury and ammonium is, however, known to exist, which affords strong 
 corroborative evidence, not only of the existence of ammonium, but also of its metallic 
 nature, metals being the only bodies which are capable of forming amalgams with 
 mercury. This singular substance, discovered simultaneously in 1808, by Seebeck, at 
 Jena, and by Berzelius and Pontin, at Stockholm, was originally prepared by the action 
 of electricity upon aqueous ammonia in contact with mercury. A strong solution of 
 aqueous ammonia in which mercury is placed, is brought into the voltaic circle, the 
 negative pole dipping into the mercury, and the positive pole into the liquid. An- 
 other method is to dip the negative wire into mercury, which is placed in a cavity 
 hollowed out of a fragment of a solid ammonium-salt, carbonate, sulphate, phosphate, 
 or chloride, the positive wire being inserted into the salt itself, or connected with a 
 metallic plate on which the salt rests. Oxygen, or, if chloride of ammonium be em- 
 ployed, chlorine, is evolved at the positive pole, but scarcely any gas at the negative 
 pole ; while the mercury increases very largely in volume, and assumes the consistence 
 of butter. When completely saturated with ammonium, the amalgam is lighter than 
 water : obtained by the former method, it has frequently a crystalline structure. It 
 is a very unstable compound, decomposing spontaneously as soon as it is removed from 
 the voltaic circle, being resolved into liquid mercury, and a mixture of 2 vols. am- 
 monia, NH 3 , and 1 vol. hydrogen, H. When cooled below C., it solidifies and crys- 
 tallises in cubes. At a very low temperature, it contracts, and becomes brittle ; 
 decomposition does not begin till the temperature rises to 29 C. According to Sir H. 
 Davy, it contains 1 atom NH 4 to 753 atoms mercury. The amalgam may also be 
 prepared without the intervention of electricity, by bringing potassium- or sodium- 
 amalgam the latter is more energetic in its action into contact with an ammonium- 
 salt, either solid and moistened with water, or as a concentrated aqueous solution. 
 The amalgam thus prepared contains, according to Gay-Lussac and Thenard, 1 part 
 nitrogen and hydrogen to 1800 parts mercury. It contains a certain portion of potas- 
 sium or sodium, and on this account is less unstable than the amalgam prepared by 
 either of the former methods : it may be preserved for a considerable time in anhy- 
 drous rock-oil, or in an atmosphere of hydrogen. 
 
 Formation. Ammonium-salts are formed by bringing ammonia or carbonate of am- 
 monium, directly into contact with acids. 
 
 Properties. Ammonium-salts are isomorphous with potassium-salts. They have 
 mostly a pungent, saline, somewhat urinous taste. They are all soluble in water, 
 generally with facility : less soluble in alcohol or ether. Ammonium-salts of colourless 
 acids are colourless. 
 
 Reactions of Ammonium-salts. Tests for Ammonia. Ammonium-salts 
 are variously affected by heat : all, however, are wholly or partially volatilised, with 
 or without decomposition. The carbonate, and those which contain no oxygen (chloride, 
 iodide, &c.), are volatilised "undecomposed. All others lose their ammonia when heated. 
 Some, e.g. the phosphate, and borate, evolve ammonia undecomposed, leaving the acid. 
 Others, e. g. sulphate, evolve nitrogen, the acid being more or less completely reduced 
 by the hydrogen of the ammonia: the nitrate is decomposed into nitrous oxide and 
 water. Their aqueous solution, when exposed to the air (still more rapidly when 
 evaporated), generally loses ammonia, an acid salt, or a normal salt mixed with excess 
 of acid, being formed : hence, in crvstallising an ammonium-salt, ammonia must be 
 occasionally added during evaporation. When treated with chlorine, their aqueous 
 solution yields hydrochloric acid and nitrogen ; or, if the salt contains a powerful acid, 
 
AMMONIAC AL SALTS. 189 
 
 hydrochloric acid and chloride of nitrogen (D nl o n g). "With a solution of hypochlorous 
 acid, dry ammonium-salts yield water, chloride of nitrogen, and nitrogen, while nitrogen 
 and chlorine remain in solution (B alard). In solution they are decomposed by pro- 
 toxides, with liberation of ammonia ; not by sesquioxides. When heated, either solid 
 or in solution, with a fixed alkali, baryta, lime, oxide of lead, &c., they evolve ammonia : 
 magnesia expels only half the ammonia, forming a double salt. 
 
 The reaction by which ammonium-salts are generally detected, is their decomposition 
 when heated with jfcm alkalis or alkaline earths. If the ammonia evolved be in so minute 
 a quantity that its characteristic smell cannot be perceived, it is easily recognised by 
 its property of restoring the blue colour to reddened litmus-paper, and of forming dense 
 white fumes by contact with a glass rod moistened with dilute hydrochloric acid. If 
 the evolved ammonia be brought into contact with a strip of paper moistened with a dilute 
 neutral solution of subnitrate of mercury, sulphate of copper, or sulphate of manganese, 
 in the first case a black stain is produced on the paper, in the second a blue, in the 
 third a brown. A solution of molybdate of sodium containing phosphoric acid (phos- 
 phomolybdate of sodium), gives with ammonium-salts, a yellow precipitate, soluble in 
 alkalis and non-volatile organic acids, insoluble in mineral acids : in very dilute am- 
 monium solutions, the formation of the precipitate is gradual ; it is accelerated by heat. 
 When a solution containing an ammonium-salt or free ammonia is mixed with potash, 
 and a solution of iodide of mercury in iodide of potassium added, a brown precipitate 
 or coloration is immediately produced (Nessler). (NH 3 + 4HgI = NHg 4 ! + SHI). 
 This is by far the most delicate test for ammonia. With dichloride of platinit/r., 
 ammonium-salts give a yellow crystalline precipitate of chloroplatinate of ammonium, 
 PtCPNH 4 , slightly soluble in water, insoluble in alcohol or acids. When ignited, the 
 precipitate is converted into pure metallic platinum, perfectly free from chlorine. 
 With acid tartrate of sodium (or tartaric acid), they give a white precipitate of acid 
 tartrate of ammonium, slightly soluble in cold water, readily soluble in alkaline solu- 
 tions and in mineral acids. The carbonaceous residue left on igniting this precipitate 
 has no alkaline reaction. A not too dilute solution of an ammonium-salt gives with a 
 concentrated solution of sulphate of aluminium, a crystalline precipitate of ammonium- 
 alum. Only very concentrated solutions of ammonium-salts give precipitates with 
 perchloric or fluosilidc acid. Subnitrate of mercury gives a brown colour in solu- 
 tions containing free ammonia. A slightly alkaline solution of an ammonium-salt 
 gives a white precipitate with chloride of mercury. Alcoholic solutions of ammonium- 
 salts burn with a blue or violet flame. 
 
 Eeactions very similar to those just described, e. g. with phosphomolybdate of sodium, 
 iodomercurate of potassium, dichloride of platinum, chloride of mercury, &c., are 
 likewise produced by the salts of methylamine, ethylamine, and other compound 
 ammonias. These organic bases may, however, be distinguished with certainty from 
 ammonia itself by igniting the substance under examination with oxide of copper, 
 and passing the evolved gases into baryta water, when, if carbon is present, a 
 precipitate of carbonate of baryta will be produced. (See ANALYSIS, ORGANIC, p. 225.) 
 
 Separation and Estimation of Ammoniu m. Ammonium is separated from 
 all other metals except the alkaline metals, by its non-precipitation by hydrosulphuric 
 acid, sulphide or carbonate of ammonium, or phosphate of sodium, in presence of chloride 
 of ammonium. From sodium and lithium it is separated by dichloride of platinum 
 and alcohol, which precipitates potassium and ammonium as chloroplatinates, while 
 sodium and lithium remain in solution. The mixed chloroplatinates are converted by 
 ignition into a mixture of metallic platinum and chloride of potassium, the latter of 
 which is dissolved out by water, the solution evaporated to dryness, gently ignited, 
 and weighed. The weight of platinum corresponding to the amount of potassium 
 thus obtained being deducted from the total weight of metallic platinum, the remaining 
 platinum represents the ammonium present : 1 atom of platinum corresponds to 1 atom 
 of ammonium. This method is applicable only when the metals are present as salts which 
 are soluble in alcohol, e. g. as chlorides. Sulphates are best converted into chlorides 
 by adding carbonate of barium, and saturating the filtrate with hydrochloric acid. 
 
 The best method for the separation of ammonium from all other metals is to heat 
 the compound under examination in a combustion-tube with excess of soda-lime, and 
 to collect the ammonia evolved in a bulb-apparatus containing hydrochloric acid. The 
 chloride of ammonium thus obtained is mixed with excess of dichloride of platinum 
 (perfectly free from nitric acid), and evaporated to dryness on a water-bath. The 
 residue is treated with alcohol, which dissolves excess of the dichloride : the chloro- 
 platinate of ammonium is collected on a weighed filter, dried at 100 C., and weighed ; 
 or converted by ignition in a porcelain crucible into metallic platinum, from the weight 
 of which the amount of ammonia is readily calculated. This method is not applicable 
 to the separation of ammonia from other volatile organic bases. 
 
 Ammonium-salts may occasionally be estimated by loss. This is the case when the 
 
190 AMMONIACAL SALTS 
 
 ammonium-salt is entirely volatile, and when no other volatile or decomposible com- 
 pound is present. The substance under examination is heated in a water-bath until it 
 ceases to lose weight : it is then moderately ignited and weighed again, when the loss 
 of weight represents the amount of ammonium-salt present. This is a convenient 
 method for the estimation of chloride, nitrate, or normal sulphate of ammonium, in 
 presence of the corresponding fixed alkaline salts. 
 
 Ammonia may also be estimated by distilling it into a known quantity of dilute acid, 
 and determining volumetrically by a standard alkaline solution the excess of free acid. 
 
 The following are the principal ammonium-salts : 
 
 1. ACETATES OF AMMONIUM, a. Normal acetate, C 2 H 3 2 .N-H 4 . A white odourless 
 salt, obtained by saturating glacial acetic acid with dry ammonia. 
 
 b. Acid acetate, C 2 H 8 2 .NH 4 + OH 4 2 . Obtained as a white crystalline subli- 
 mate, when dry powdered chloride of ammonium is treated with an equal weight of 
 acetate of potassium or calcium, ammonia being given off simultaneously. (See ACE- 
 TATES, p. 1'2.) 
 
 2. CARBONATES OF AMMONIUM. H. Kose (Pogg. Ann. xlviii. 352) admits the 
 existence of a considerable number of carbonates of ammonium, to which he assigns 
 very various and complicated formulae. But, according to H. Deville (Compt. rend. 
 xxxiv. 880 ; Ann. Ch. Phys. [3] xl. 87), there exist only two carbonates of ammonium 
 of definite composition. 
 
 a. Normal carbonate, C0 3 (NH 4 ) 2 [or CO\NH*0 = C0 2 .NH*.HO].This salt has 
 never been isolated. The salt which crystallises from an alcoholic solution of sesqui- 
 carbonate of ammonium saturated with ammonia, is simply sesquicarbonate. Neither 
 can it be obtained from a saturated solution of commercial sesquicarbonate in strong 
 aqueous ammonia. It may be obtained in aqueous or alcoholic solution, or, as sesqui- 
 carbonate, in combination with the acid carbonate (b). (PelouzeetFremy, Traite 
 de Chimie, ii. 222.) 
 
 b. Acid carbonate, C0 3 .NH 4 .H [or CO*.NH*0 + CO S .HO.] Obtained by saturating 
 an aqueous solution of ammonia or sesquicarbonate of ammonium with carbonic an- 
 hydride. Or by treating the commercial sesquicarbonate finely powdered, with alcohol 
 of 90 per cent., which dissolves out normal carbonate, leaving a residue of acid car- 
 bonate. Sesquicarbonate of ammonium is similarly decomposed by cold water ; but 
 in this case, a larger quantity of the acid carbonate is dissolved. All carbonates of 
 ammonium, when left to themselves, are gradually converted into acid carbonate. It- 
 forms large crystals, belonging to the right prismatic or trimetric system. According 
 to Devi lie, it is dimorphous, but never isomorphous with acid carbonate of potassium. 
 When exposed to the air, it volatilises slowly, without becoming opaque, and gives off 
 a slight ammoniacal odour. At the ordinary temperature, it is soluble in 8 parts 
 of water ; if this solution be heated above 36 0,, it is decomposed, evolving carbonic 
 anhydride. Even at ordinary temperatures, the solution, whether concentrated or dilute, 
 gradually becomes ammoniacal on keeping (G-melin). It is insoluble in alcohol; 
 but when exposed to the air under alcohol, it dissolves as normal carbonate, evolving 
 carbonic anhydride. 
 
 It has been found native in considerable quantity in the deposits of guano on the 
 western coast of Patagonia, in the form of white crystalline masses, with a strong 
 ammoniacal smell. (Ulex. Ann. Ch. Pharm. Ixvi. 44.) 
 
 c. Sesquicarbonate, C 3 9 N 4 H 18 + 2H 2 [= ZCCP.INWO + 3HO.] Obtained by 
 dissolving commercial carbonate of ammonium in strong aqueous ammonia, at about 
 30 C., and crystallising the solution. It forms large transparent crystals, representing a 
 right rectangular prism, with the faces of the corresponding rhombic octahedron 
 resting on the angles. These crystals decompose very rapidly in the air, losing water 
 and ammonia, and being converted into di-acicl carbonate. This salt may be regarded 
 as a mixture or compound of 1 atom of normal carbonate with 2 of atoms acid carbonate 
 [CO 3 . (NH 1 ) 2 + 2(C0 3 .NH 4 .H) = C 3 9 N 4 H 18 ] : a view which is confirmed by its be- 
 haviour with water and alcohol ; which, when added in quantity insufficient for the 
 complete solution of the salt, dissolves out normal carbonate, leaving a residue of acid 
 carbonate: 100 pts. water at 13 C. dissolve 25 pts. sesquicarbonate, at 17, 30 pts. ; at 
 32, 37 pts. ; at 41, 40 pts. ; at 49, 60 pts. (Berzelius) : above this temperature, 
 carbonic anhydride is evolved, and a solution of normal carbonate formed. 
 
 Commercial carbonate of ammonium (sal volatile, salt of hartshorn, &c.) consists 
 of sesquicarbonate, more or less pure. It is prepared on a large scale by the dry dis- 
 tillation of bones, hartshorn, and other animal matter. The product thus obtained is 
 contaminated with empyreumatic oil, from which it is purified by subliming it once op 
 twice with 1| times its weight of animal charcoal, in cast-iron vessels over which glass 
 receivers are inverted. By repeated sublimation, the salt is partially decomposed. 
 Another method of preparing it is by heating to redness a mixture of 1 pt. chloride or 
 sulphate of ammonium, and 2 pts. carbonate of calcium (chalk), or carbonate of potassium, 
 
CARBONATES CHLORIDE. 191 
 
 in a retort to which a receiver is luted : ammonia and water are first disengaged, and 
 then the sesquicarbonate distils over and solidifies in the neck of the retort and the 
 receiver. On a small scale, glass vessels are employed : on a large scale, an earthenware 
 or cast-iron retort, and an earthenware or leaden receiver, which, when filled by 
 repeated distillations, is broken or cut in two: 10 pts. sal-ammoniac yield from 7 to 8 
 pts. sesquicarbonate. (See Dictionary of Arts, Manufactures and Mines, i. 135.) The 
 salt thus prepared is liable to contain the following impurities : 
 
 Hypostupkite of ammonium: when sulphate of ammonium, or chloride containing 
 sulphate, is employed in the preparation. The salt neutralised with acetic acid gives 
 a white precipitate which turns black on addition of nitrate of silver. Sulphate of 
 ammonium, from the same causes : detected by hydrochloric acid and chloride of barium. 
 Sal-ammoniac: detected by nitric acid and nitrate of silver. Lead, from the receiver : 
 the salt has a grey colour, and when dissolved in dilute nitric acid, gives the reactions 
 of lead. Lime and chloride of calcium, carried over mechanically : from these and 
 other fixed impurities the salt is freed by re-sublimation. 
 
 The sesquicarbonate obtained as above is a white, transparent, fibrous mass, with 
 a pungent caustic taste, and a strong ammoniacal smell. .Exposed to the air, it is 
 gradually converted into acid carbonate. It is completely volatile, though not without 
 partial decomposition. Its aqueous solution is strongly alkaline : from a hot saturated 
 solution, the acid carbonate crystallises on cooling, but not in the ordinary crystalline 
 form. (Deville.) 
 
 The aqueous solution of this salt (spiritus salis ammoniaci), is extensively employed 
 in me'dicine as a stimulant. It is also a very valuable reagent. The solid salt is 
 employed in the manufacture of other ammoniacal salts. 
 
 3. CHLOEIDE or AMMONIUM, C1NH 4 . (Hydrochlorate or muriate of ammonia, Sal- 
 ammoniac, salzsaures Ammoniak, SalmiaJc, Chlorure d 'ammonium, or Chlorure am- 
 moniquc.') 
 
 Hydrochloric acid gas and ammonia combine volume for volume, with great evolu- 
 tion of heat, forming solid chloride of ammonium. This salt forms colourless feathery 
 crystals, which, when examined by a lens, are found to consist of an aggregation of 
 cubes or octahedrons. It has no smell, but a pungent taste ; its specific gravity is 1'5. 
 It dissolves in 2*72 pts. water at 18'75 C., with great reduction of temperature ; and in 
 about its own weight of water at 100. It is less soluble in alcohol. When exposed 
 to the air, it loses ammonia, and becomes acid to test-paper. When heated, it vola- 
 tilises undecomposed, without previous fusion. After sublimation, it forms white 
 crystalline masses, which are exceedingly tough and difficult to powder : to obtain it 
 in a pulverulent state, a hot saturated solution is evaporated to dryness very rapidly, 
 with continual agitation, when the salt is left as a crystalline powder. 
 
 Chloride of ammonium is decomposed by several metals, potassium, iron, &c., a 
 metallic chloride being formed, and ammonia and hydrogen separated. It is also 
 decomposed by many salts; by some, e.g. alkaline and alkaline-earthy hydrates, 
 completely, ammonia being evolved ; by others, as by cupric and ferric salts, partially, 
 double salts being formed. Some salts, e. g. platinic chloride, combine with it 
 directly, forming double salts (chloroplatinates). Some metallic hydrates are soluble 
 in a solution of sal-ammoniac, especially those of zinc and magnesium. 
 
 Sal-ammoniac is found native in many volcanic regions ; also in small quantities in 
 sea-water. It is readily formod by heating nitrogenised animal matter containing 
 chloride of sodium, or with which that salt has been mixed. Until the middle of the 
 last century, sal-ammoniac was obtained almost exclusively from Egypt, where it was 
 prepared in this manner, by subliming the soot obtained by the combustion of camel's 
 dung. It is now largely manufactured in Europe, chiefly from the impure carbonate 
 of ammonium which is obtained in gas-works, or by the dry distillation of animal 
 matter. This carbonate is converted into chloride by the addition of hydrochloric 
 acid, or of the mother- liquor from salt-works, containing the chlorides of magnesium 
 and calcium, and by evaporating the solution (ammonia being added from time to time), 
 crystals of sal-ammoniac are obtained. These are contaminated with empyreumatic 
 oil, which is destroyed by heating the crystals to a temperature a little below their 
 subliming point. They are then dissolved in water, the solution decolorised by boiling 
 with animal charcoal, and again crystallised. The salt is finally purified by sublima- 
 tion, which is performed at a brisk heat, in large glass or earthenware bottles, the 
 neck of which must be carefully kept unobstructed, to avoid the risk of explosion : the 
 bottles are then broken and the sal-ammoniac removed in cakes. Metallic receivers 
 are sometimes employed in the sublimation ; in this case, the outer surface of the sal- 
 ammoniac is dark-coloured, owing to metallic impurities, and must be scraped off. 
 
 In some manufactories, the carbonate of ammonium is first converted into sulphate, 
 and subsequently into chloride. This is generally done by filtering the solution of 
 carbonate through a stratum of powdered gypsum (sulphate of calcium), when insoluble 
 
192 AMMONIACAL SALTS. 
 
 carbonate of calcium is formed, arid a solution of sulphate of ammonium obtained. 
 This solution is mixed with chloride of sodium, evaporated to dryness, and the sal- 
 ammoniac separated from the residue by sublimation. Or the solution of the two salts 
 is evaporated at the boiling heat, when sulphate of sodium, being less soluble at a hifji 
 than at a lower temperature, mostly crystallises out and is removed. The solution is 
 then cooled, when the sal-ammoniac crystallises out, since its solubility diminishes 
 rapidly with decrease of temperature. The crystals thus obtained are purified as 
 above described. Ferrous sulphate may be employed instead of gypsum to convert 
 the carbonate of ammonium into sulphate ; this is a more expensive process, but it 
 possesses the advantage of removing the greater part of the empyreumatic oil, which 
 is carried down by the precipitated iron-salt. (Berzelius.) 
 
 In the factory at Buxweiler, in Alsace, sal-ammoniac, phosphorus, and gelatin are 
 prepared by the following ingenious process. Bones are digested in hydrochloric acid, 
 which dissolves out the bone-earth, leaving the cartilage insoluble : the latter is em- 
 ployed for the preparation of gelatin. The hydrochloric solution is mixed with crude 
 carbonate of ammonium, when sal-ammoniac is formed, and phosphate of calcium preci- 
 pitated in the finely-divided state in which it is best adapted for the preparation of 
 phosphorus. [For further details of the manufacture of sal-ammoniac, see Dictionary 
 of Arts, Mamtfacturcs and Mines, i. 141.] 
 
 Sal-ammoniac is employed in medicine. In the laboratory it serves for the pre- 
 paration of ammonia, and carbonate of ammonium, and for frigorific mixtures. It is 
 employed in dyeing ; also in metal- works, as a deoxidising agent, especially for copper. 
 A solution of chloride of silver in chloride of ammonium is employed for plating cop- 
 per and brass. It enters into the composition of a cement used for fixing iron in 
 stone: this cement is formed by moistening with a solution of sal-ammoniac, iron- 
 filings mixed with 1 or 2 per cent, sulphur. Impure sal-ammoniac has recently been 
 employed as manure. 
 
 4. HYDRATE OF AMMONIUM, NH 4 .H.O. This compound has never been isolated. 
 The aqueous solution of ammonia behaves in many respects like a solution of hydrate 
 of ammonium. 
 
 5. NITRATE OF AMMONITJM, N0 3 .NH 4 [or N0 5 .NH*0 = N0 5 .NH 3 .HO~]. (Nitrum 
 flammans.} Obtained by crystallising a mixture of nitric acid with a slight excess of 
 aqueous ammonia. It forms long flexible needles : if the crystallisation be effected 
 very slowly, it may be obtained in six-sided prisms. When the solution is evaporated to 
 a very small bulk, the salt solidifies into a dense amorphous mass. It has a pungent 
 taste. It is soluble in about half its weight of water at 18 C., and in still less at 100 : 
 its saturated solution boils at 164 C., and contains 47'8 per cent, salt: when dissolved 
 in water it produces great cold. It is soluble in alcohol. Exposed to the air, it deli- 
 quesces slightly, loses ammonia, and becomes acid. When heated, it fuses perfectly 
 at 108 C., and boils without decomposition at 180. Between 230 and 250 it is de- 
 composed into water and nitrous oxide, (N0 3 .NH 4 = N 2 + 2H 2 0). If it be heated 
 too rapidly, ammonia, nitric oxide, and nitrite of ammonium are also formed. (Ber- 
 zelius). When thrown into a red-hot crucible, it burns with a slight noise, and a 
 pale yellow flame. In presence of spongy platinum, it is decomposed at about 170 C. 
 into nitrogen and nitric acid. (M i 1 1 o n and R e i s e t.) 
 
 Nitrate of ammonium is formed when a mixture of nitrogen, oxygen, and excess of 
 hydrogen is submitted to the electric current ; also when hydrosulphuric acid is passed 
 into a dilute solution of nitric acid. It is also formed by the action of nitric acid on 
 several metals, especially tin. 
 
 6. NITRITE OF AMMONIUM, N0 2 .NH 4 [ = NO*.NH 3 .HO]. Obtained by double decom- 
 position of nitrite of lead and sulphate of ammonium, or of nitrite of silver and chloride 
 of ammonium : the solution is evaporated in vacuo. Or by passing nitrous fumes into 
 aqueous ammonia, and evaporating over lime (Mi 11 on). It forms an imperfectly 
 crystallised mass. It is decomposed by heat into nitrogen and water, (NO'^.NH 4 N 2 
 + 2H 2 0). Its aqueous solution is similarly decomposed, suddenly if acid, gradually 
 if alkaline. 
 
 7. OXALATES OF AMMOXIUM. a. Normal oxalate. C 2 O 4 (NH 4 ) 2 + H 2 0. Obtain"l 
 by neutralising oxalic acid with ammonia, and crystallising. It forms long prisms 
 united in tufts, belonging to the rhombic, right prismatic or trimetrie sv.stem : soluble 
 in 3 pts. cold water, insoluble in alcohol. It is very slightly volatile at ordinary 
 temperatures. When carefully heated to 220 C. it is entirely decomposed into carbonic 
 oxide and carbonate of ammonium ; when it is heated more strongly, some oxamide is 
 formed. Its solution is employed as a reagent for precipitating calcium-salts. 
 
 b. Acid oxalate, C 2 0'.NH 4 .H + H 2 0. - Obtained in the crystalline form by adding 
 oxalic, sulphuric, nitric, or hydrochloric acid to a solution of the normal salt. It crys- 
 tallises in the trimetrie system. It reddens litmus, and is less soluble than the normal 
 
PHOSPHATE SULPHIDE. 193 
 
 salt. It is decomposed by heat, yielding, among other products, oxamide, C 2 2 N 2 H 4 , 
 and oxamic acid, C 2 3 NH 7 . 
 
 c. Quadroxalate, Hyper-acid oxalate, C 2 4 .NH 4 .H + C 2 4 H 2 + 2H 2 0. Obtained 
 by crystallising a solution of equal parts of acid oxalate and oxalic acid. The crystals 
 belong to the triclinic or doubly oblique prismatic system, and are isomorphous with 
 the corresponding potassium salt. They are very soluble in hot water. At 100 C. 
 they effloresce slightly, and lose their water of crystallisation. 
 
 8. PHOSPHATES OF AMMONIUM. a. Normal phosphate, P0 4 (NH 4 ) 8 [or PO^N^O.] 
 When a solution of monacid phosphate of ammonium is mixed with ammonia, 
 this salt separates as a crystalline magma : it cannot be dried without losing ammonia, 
 being converted into b. 
 
 b. Diammonic phosphate, P0 4 .(NH 4 ) 2 .H [or PCP.1NIPO.HO]. (Ordinary phosphate 
 of ammonium, formerly called neutral phosphate.') Obtained by adding a slight excess 
 of ammonia or carbonate of ammonium to acid phosphate of calcium (solution of bone- 
 earth in hydrochloric or dilute sulphuric acid) ; when phosphate of calcium is precipitated, 
 and monacid phosphate of ammonium remains in solution. It forms large, colourless, 
 transparent crystals, belonging to the monoclinic or oblique prismatic system. It has 
 a cooling, saline taste, and an alkaline reaction. Exposed to the air, it effloresces 
 slightly, losing ammonia. It is soluble in 4 pts. cold, and in a smaller quantity of 
 boiling water; insoluble in alcohol. By a red heat, it is converted into metaphosphoric 
 acid, P0 4 .(NH 4 ) 2 .H = P0 3 H + 2NH 3 + H 2 0). 
 
 c. Monammonic phosphate, P0 4 .(NH 4 ).H 2 [or PO*.NIP0.1HO]. (Formerly called 
 acid phosphate.) Obtained by adding phosphoric acid to aqueous ammonia, till the 
 solution is strongly acid, and no longer precipitates chloride of barium ; or by boiling 
 a dilute solution of b and evaporating it to crystallisation. It crystallises in the dimetric 
 or square prismatic system. It is somewhat less soluble in water than b, and is 
 similarly decomposed by heat. 
 
 The phosphates of ammonium are employed for the preparation of metaphosphoric 
 acid. As the residue of their ignition always retains ammonia, it must be moistened 
 with nitric acid, and again calcined. Gay-Lussac has proposed to preserve muslins 
 and other inflammable textures from ignition by steeping them in a solution of these 
 salts ; the salt being decomposed by heat, the tissue is covered with a film of metaphos- 
 phoric acid, which preserves it from contact with the air, and prevents its breaking 
 into flame. These salts cannot, however, be applied to fabrics which have to be 
 washed and ironed, because the heat of the iron would decompose them, expelling the 
 ammonia. The same objection applies to sulphate of ammonium, which is otherwise 
 efficacious in diminishing the inflammability of light tissues. From recent experiments 
 by Versmann and Oppenheim (Pharm. J. Trans. [2] i. 385), it appears that the 
 only salt universally applicable for rendering such fabrics non-inflammable, is the 
 neutral tungstate of sodium. (See TUNGSTATES.) 
 
 Some of the double phosphates of ammonium and other metals are of considerable 
 importance. The phosphate of sodium, ammonium and hydrogen, P0 4 .Na.NH 4 .H, com- 
 monly called microcosmic salt, or phosphorus salt, is much used as a blow-pipe flux, 
 being converted by heat into transparent metaphosphate of sodium, which dissolves 
 many metallic salts with characteristic colours. 
 
 9. SULPHATES OF AMMONIUM. a. Normal Sulphate, S0 4 (NH 4 ) 2 [or S0 3 .NH*0.] 
 (Glauber's Sel secretum.) Obtained by neutralising dilute sulphuric acid with 
 ammonia or carbonate of ammonium. It forms crystals belonging to the trimetric or 
 right prismatic system, isomorphous with potassic sulphate. It is colourless, and has 
 a very bitter taste ; it is soluble in twice its weight of cold, and in its own weight of 
 boiling, water; insoluble in alcohol. It fuses at 140 C: above 280, it is decomposed, 
 ammonia, nitrogen, and water being given off, and acid sulphite of ammonium 
 sublimed. 
 
 It is found native as Mascagnine. It is manufactured on a large scale (as already 
 described \inder Sal-ammoniac) by neutralising with sulphuric acid, or decomposing 
 by gypsum, the impure carbonate of ammonium obtained in gas-works, &c. and crys- 
 tallising the solution. The crystals are heated, to destroy animal matter, and purified 
 by recrystallisation. Sulphate of ammonium is employed in the manufacture of am- 
 monium-alum : also as manure. 
 
 b. Add sulphate, S0 4 .NH 4 .H, [or 2 S0 3 .NIPO.HO]. Obtained by treating a solution 
 of a with sulphuric acid. It crystallises in thin rhombohedrons. It is soluble in its 
 own weight of cold water, and in alcohol. It deliquesces slowly in the air. 
 
 10. SULPHIDES OF AMMONIUM. a. Sulphide, (NH 4 ) 2 S. When a mixture of dry hy- 
 drosulphuric acid and ammonia, the latter in excess, is exposed to a temperature of 
 18 C. 2 vols. ammonia combine with 1 vol. hydrosulphuric acid, and form sulphide 
 of ammonium. The same compound is formed when sulphide of potassium is distilled 
 
 VOL. I. O 
 
194 AMMONIUM-BASES. 
 
 with chloride of ammonium, provided the receiver be cooled to 18 C. It forms 
 colourless crystals, which have a strong alkaline reaction. At the ordinary temperature, 
 it is at once decomposed, losing ammonia, and being converted into sulphyclrate (6). 
 This decomposition takes place even in an atmosphere of ammonia. Its aqueous solu- 
 tion, which is much employed as a reagent, is prepared by dividing a saturated 
 solution of ammonia into 2 equal parts, saturating one with hydrosulphuric acid, and 
 then adding the other. It forms a colourless solution, which becomes yellow on 
 keeping, owing to the formation of a higher sulphide ; by further exposure to the 
 air, sulphur is separated, hyposulphite, sulphite, and finally sulphate of ammonium 
 being successively formed. 
 
 b. Sidphydrate or Hydrosulphate, NH 4 .H.S. Obtained by mixing dry hydrosul- 
 phuric acid and ammonia, in any proportions, at a temperature above 18 C. It 
 is a combination of the two gases in equal volumes. It forms colourless crystals, which 
 have an alkaline reaction, and volatilise undecomposed, even at ordinary temperatures. 
 Its aqueous solution is obtained by saturating aqueous ammonia with washed hydrosul- 
 phuric acid, out of contact with the air. It forms a colourless solution, which, by ex- 
 posure to the air, is decomposed in the same manner as the sulphide. 
 
 c. Poly sulphides. Besides the above, there are several other compounds of sulphur 
 and ammonium described, which may be regarded as combinations of the monosul- 
 phide with sulphur, or as poly sulphides of ammonium. These are 1. The disulphide, 
 (NH 4 ) 2 S 2 ; 2. The trisulphide, (NH 4 ) 2 S 3 ; 3. The tetrasulphide, (NH 4 ) 2 S 4 ; 4. The 
 pentasulphide, (NH 4 ) 2 S 5 ; 5. The heptasulphide, (NH 4 ) 2 S 7 . The most general method 
 of preparing these compounds is by distilling the corresponding sulphide of potassium 
 with excess of chloride of ammonium. In the wet way, they are prepared by adding 
 sulphur to a solution of the monosulphide, and saturating the mixture alternately with 
 ammonia and hydrosulphuric acid. The heptasulphide, to which there is no corre- 
 sponding sulphide of potassium, is formed by the spontaneous decomposition of the 
 pentasulphide : 
 
 3(NH') 2 S 5 = 2(NH 4 ) 2 S' + NH 3 + NH'.H.S. 
 
 It forms ruby-red crystals. It is the most stable of the polysulphides of ammonium, 
 not being decomposed at temperatures below 300 C., and but very slowly by water or 
 hydrochloric acid. 
 
 The substance known as fuming liquor of Boyle, or volatile liver of sulphur, is a 
 mixture of two or more sulphides of ammonium. It is obtained by distilling a mix- 
 ture of 1 pt. sulphur, 2 pts. sal-ammoniac, and 2 to 3 pts. quick lime. It is a dark 
 yellow liquid, of penetrating smell : it fumes strongly in the air, or in any gas con- 
 taining oxygen, not in gases free from oxygen. It is capable of taking up more 
 sulphur, forming a syrupy fluid, which no longer fumes on contact with air. F. T. C. 
 
 A hypothetical metal, whose composition is expressed by the 
 formula NH 4 : it is supposed to be contained in ammoniacal salts. (See AMMO- 
 NIACAL SALTS, p. 188.) 
 
 AIKXKOia-XUM-.A.llXAX.G.A.XK. (p. 188.) 
 
 A1VI1VTOTJIU1VI-BASES. In very many cases, the watery solution of ammonia 
 behaves with other bodies exactly like a solution of potash or soda. We cannot 
 express this similarity in our chemical formulae, if we regard liquid ammonia as a mere 
 solution of ammonia, NH 3 , in water : it only becomes comparable to the fixed alkalis 
 when we regard it as containing a compound of ammonia with water, NH 3 .H 0. In 
 order to express this relation still more precisely, Berzelius proposed to represent 
 aqueous ammonia as containing the hydrated oxide of the compound group, NH 4 , 
 
 (NH 3 .H 2 = TT [ 0), to which he gave the name Ammonium, and by means of which 
 
 the ammonia-salts can be represented as exactly analogous to those of potassium, 
 sodium, or the metals generally (see AMMONIUM-SALTS, p. 188). In the article 
 AMIDES, it is shown that a very large number of bodies may be formed from ammonia, 
 by replacing a part or the whole of its hydrogen by other radicles, simple or compound. 
 When the hydrogen of ammonia is replaced by the alcohol-radicles (methyl, ethyl, 
 &c.), or by other bodies which more or less resemble hydrogen in their general 
 chemical characters, the resulting compounds (Amines') retain the most important 
 property of ammonia itself, namely, the property of forming definite salts by direct 
 union with acids. It is evident that, if it is wished to express the analogy of the salts 
 of these derivatives of ammonia with the metallic salts, they may be represented as 
 containing ammonium in which part of the hydrogen is replaced by other radicles : 
 for instance, hydrochlorate of triethylamine, NC 6 H 18 C1, may be viewed as chloride of 
 triethylammonium, [N(C 2 H 5 ) 3 H]C1, analogous to chloride of ammonium, (NH 4 )Cl, and 
 chloride of potassium, KC1. 
 
AMMONIUM-BASES. 195 
 
 But since only three-fourths of the hydrogen of the ammonium in ammonia-salts is 
 derived from ammonia, the other fourth belonging to the acid, it is plain that the 
 compounds of the derived ammonias with acids never represent ammonium-salts in 
 which more than three-fourths of the hydrogen is replaced. But, by the combination 
 of tertiary amines (derivatives of ammonia by the replacement of all three atoms of 
 hydrogen by methyl, ethyl, or similar radicles), with the chlorides, bromides, or iodides 
 of the alcohol-radicles, compounds are formed which represent ammonium-salts in 
 which all the hydrogen is replaced by other radicles (see AMIDES, p. 175) : e.g. 
 
 K(C 2 H 5 ) 3 + C-IF.I = K(C 2 H 5 ) 4 I 
 Triethylamine. Iodide of Iodide of 
 ethyl. tetrethylium. 
 
 Notwithstanding the obvious analogy of this mode of formation to the formation of 
 the salts of amines by the action of the iodides, &c, of alcohol-radicles on am- 
 monia e. g. : 
 
 NH 8 + C 2 H 5 I = N.(C 2 H 5 .H 3 )I; 
 
 Iodide of Hydriodate of 
 
 ethyl. ethylamine. 
 
 the seriation which connects this class of bodies with the ammonium-salts : 
 
 N.H . H . H . H . I, hydriodate of ammonia, or iodide of ammonium, 
 N.C 2 H 5 . H . H . H .1, ethylamine, ethylium, 
 
 KC 2 H 5 . C 2 H 5 . H . H . I, diethylamine diethylium, 
 
 N.C 2 H 5 . C 2 H 5 . C 2 H 5 . H . I, triethylamine triethylium, 
 
 N.C 2 H 5 . C 2 H 5 . C 2 H 5 . C 2 H 5 . I, iodide of tetrethylium ; 
 
 and the applicability of the ammonium-theory to express the nature of the salts of the 
 amines, as pointed out above the derivatives of the ammonium-salts by the replace- 
 ment of all the hydrogen of the ammonium, nevertheless exhibit some important general 
 differences from the salts of the amines. For example, when caustic potash or lime is 
 added to a salt of ammonia, or of an amine, the salt is decomposed, even in the cold, and 
 ammonia, or a derivative, is set at liberty ; on the other hand, iodide of tetrethylium, 
 or a similar compound, is not decomposed by potash ; it can however be decomposed 
 by hydrate of silver ; but, even then, there is no separation of a derivative of ammonia, 
 but hydrate of tetrethylium, N.(C 2 H 5 ) 4 .H.O, or a similar body, is formed: 
 
 N(C 2 H 5 ) 4 I + AgHO = N(C 2 H 5 ) 4 .H.O + Agl. 
 
 Iodide of Hydrate of 
 
 tetrethylium. tetrethylium. 
 
 In the first case, the hydrate of ammonium, which may be supposed to be formed in 
 the first stage of the reaction, is decomposed into ammonia and water : in the second case, 
 the substance which represents hydrate of ammonium is stable and has the properties 
 of a strong alkali. This difference makes it convenient to have some general term to dis- 
 tinguish such bodies as hydrate of tetrethylium from such tasic hydrates as* decompose, 
 at the moment of their formation, into a representative of ammonia and water. The 
 former class of substances are therefore often spoken of as ammonium-bases, in contra- 
 distinction to the amine- or ammonia-bases. 
 
 The formation of the ammonium-bases is specially interesting in connection with 
 the theory of ammonium. It is impossible to isolate the hydrate of ammonium, which, 
 according to that theory, exists in solution of ammonia, or to obtain a corresponding 
 compound from any of the compound ammonias; but the ammonium -bases are repre- 
 sentatives of hydrate of ammonium, which correspond to the hydrates of potassium 
 and sodium, not only in their formulae, but very closely in their properties. Their 
 concentrated solution is caustic to the touch ; by evaporation, they are obtained as 
 crystalline substances, very soluble in water, which liberate ammonia from its salts, 
 dissolve most of the metallic oxides which are soluble in potash, and decompose com- 
 pound ethers into the corresponding acid and alcohol. At a high temperature, they 
 are decomposed, with formation of a tertiary amine : 
 
 K(C 2 H 5 ) 4 .H.O = N.(C 2 H 5 ) 3 + C 2 H 4 + H 2 0. 
 
 Hydrate of Triethyl- Ethy- 
 
 tetrethylium. amine. lene. 
 
 Their iodides, or similar salts, are similarly decomposed by heat : 
 N(C 2 H 5 ) 4 I = N(C-H 5 ) 3 + C 2 H 5 .L 
 
 Iodide of Triethyl- Iodide 
 
 tetrethylium. amine. of ethyl. 
 
 _ The tertiary derivatives of phosphide, arsenide, and antimonide of hydrogen, give 
 rise to precisely similar compounds by combination with hydriodic ethers and suroe* 
 
 o 2 
 
196 AMMONIUM-BASES. 
 
 quent decomposition of the iodide so formed, by hydrate of silver. The decomposition 
 by heat of the hydrates of the phosphonium-bases, differs from that of the correspond- 
 ing ammonium-bases : e. g. 
 
 P(C 8 H 5 ) 4 H.O = P(C 2 H 5 ) 3 + C 2 H 5 .H. 
 
 Hydrate of Oxide of Hydride of 
 
 tetrethyl- triethylphos- ethyl, 
 
 phosphonium. phine. 
 
 POLY AMMONIUM-BASES. These compounds bear to the monammonium -bases 
 just described, the same relation that the diamines and triamines bear to the mon- 
 amines : they may be considered as representing two or more molecules of hydrate of 
 ammonium in which the whole or part of the hydrogen is replaced by polyatomic 
 radicles. As in the case of the monammonium-bases, there is a difference between the 
 polyammonium-bases in which only part of the hydrogen is replaced, and those in 
 which it is all replaced : the former cannot be obtained in the isolated state ; the latter 
 are stable compounds and possess strong alkaline properties. But both these classes 
 of hydrates have been less studied, and are therefore hitherto less important, than the 
 corresponding salts, which are for the most part equally stable, whether still containing 
 replaceable hydrogen, or no. We shall therefore in this article treat of the poly- 
 ammonium compounds generally, making no essential distinction between hydrates 
 and other salts, or between those compounds in which the hydrogen of ammonium is 
 wholly, and those . in which it is partially replaced. Moreover, as the bodies of this 
 class containing phosphorus and arsenic have been at least as much studied as those 
 containing nitrogen, it will be most convenient to speak of the action of polyatomic 
 compounds on the basic derivatives of ammonia generally, taking as special examples 
 of the various reactions hitherto known, compounds containing nitrogen, phosphorus, 
 or arsenic, as these or those happen to be best known. 
 
 A. ACTION OF DIATOMIC CHLORIDES, BROMIDES, OR IODIDES : 
 
 1. On Ammonia. 
 
 The experiments which have been made in this direction are almost confined to 
 the action of bromide of ethylene on ammonia. The products thus formed are the 
 following : 
 
 Dibromide of ethylene-diammoniuum . . . N 2 (C 2 H 4 )H 6 Br 2 
 
 Dibromide of diethylene-diammonium . . 
 
 Dibromide of triethylene-diammonium . . 
 These compounds, when distilled with potash, give, respectively, ethylenamine, 
 
 N 2 (C 2 H 4 )H 4 , diethylenamine, N 2 (C 2 H 4 ) 2 H 2 , and triethylenamine, N 2 (C 2 H 4 ) 3 , bodies 
 which are likewise acted on by bromide of ethylene, the final product being a substance 
 very analogous to bromide of tetrethylium, and which is probably dibromide of 
 
 tetrethylene-diammonium,N 2 (C 2 H 1 ) 4 Br 2 . 
 
 2. On Primary derivatives of ammonia, primary amines. 
 Bromide of ethylene gives with ethylamine and phenylamine : 
 
 Dibromide of ethylene-diethyl-diammonium . . N 2 (C"H 4 )(C 2 H 5 ) 2 H 4 Br 2 
 
 Dibromide of diethylene-diethyl-diammonium . N 2 (C 2 H 4 ) 2 (C 2 H 5 ) 2 H 2 Br 2 . 
 and similar phenyl-compounds. 
 
 3. On Tertiary derivatives of ammonia. 
 
 Just as dibasic acids can combine with one or with two atoms of ammonia, so like- 
 wise can diatomic ethers (such as chloride or bromide of ethylene, or iodide of methy- 
 lene) combine with one or with two atoms of the tertiary derivatives of ammonia.* 
 Thus triethylphosphine with bromide of ethylene gives the compounds 
 
 " Bromide of bromethyl-triethylphosphonium" (Ho f mann ). 
 " Bromide of ethylene-hexethyl-diphosphonium " (H of mann). 
 
 The condition of the bromine contained in these compounds is worth noticing. The 
 addition of nitrate of silver to a solution of the first compound precipitates only half 
 the bromine contained in it, but nitrate of silver precipitates all the bromine contained 
 in the second. This difference is explained by Hofmann, by supposing that 1 atom of 
 
 Bromide of ethylene and iodide ofmethylene combine directly with only 1 atom of the tertiary 
 amines, but the compounds with two atoms can be obtained by the action of hydrobromic, or hydriodic 
 ethers on ethylenamine. 
 
AMMONIUM-BASES. 197 
 
 bromine in the first compound is contained in the form of bromethyl, C 2 H 4 Br : his 
 view of the constitution of the two compounds is expressed in the names quoted 
 above. It is not, however, difficult to account for the difference in the behaviour of 
 the two bromides without making this supposition. When we remember that the 
 bromine in bromide of ethyl is not precipitated by nitrate of silver, but that it 
 becomes so immediately bromide of ethyl is combined with ammonia or an analogous 
 body, it does not seem surprising that one of the two atoms of bromine in bromide of 
 ethylene should become saline (or accessible to ordinary reagents) when that body is 
 combined with one molecule of a representative of ammonia, and that both atoms 
 should become saline when it is combined with two molecules of an ammonia-deriva- 
 tive. In all compounds formed upon the model of the first compound, only 1 atom of 
 the salt-radicle is precipitable by nitrate of silver ; in all those formed upon the model 
 of the second, both atoms are precipitable. 
 
 The following are the most important transformations of the above or similar bodies. 
 
 a. The compound /Q2jTs-\3p ( i s decomposed by heat thus : 
 
 C 2 H 4 Br 2 ) _ m , C 2 H 3 Br 
 (C 2 H 5 ) 3 Pj = f (C 2 H 5 ) 3 Pi 
 
 Bromide of vinyl-trie- 
 thylphosphonium. 
 
 b. When a dilute solution is treated with hydrate of silver, it loses all its bromine 
 
 ^r^2TT4V'TT2 f)2) 
 
 and gives /rj2Tp4p ' [> which may be regarded as a compound of triethylphosphine 
 
 with glycoL This substance is a strong base, but, as in the bromine compound, only 
 one half of the elements combined with the ethylene, are directly replaceable by acid 
 
 p2TT4 fff) p] ) 
 
 radicles (e. g. hydrochloric acid gives /Q2jp)sp* [ ) : with bromide of phosphorus, it 
 regenerates the original bromine-compound. In a concentrated solution, hydrate of 
 silver gives /n2TT5\sp ( differing from the last substance by the elements of an atom of 
 
 water. This compound may be regarded as containing oxide of ethylene and triethyl- 
 phosphine, and belongs to the same class of bodies as the bases * which Wurtz ob- 
 tained by the action of ammonia on oxide of ethylene : 
 
 C 2 H.0 ) 2(C 2 H 4 .0)) 3(C 2 H 4 .0)) 
 
 (C 2 H 5 ) 3 Pj HN{ H 3 N C 
 
 Ethylene-triethyl- Diethylene- Triethylene- 
 
 hydorphosphine. dihydoramine. trihydoramine. 
 
 c. The same compound is converted by acetate of silver at 100 C. into acetate of 
 vinyl-triethylphosphonium, P(C 2 H 5 ) 3 C 2 H 3 .C 2 H 3 2 . This reaction probably has two 
 stages : 
 
 1 
 
 2 C 2 H 4 .(C 2 H 3 2 ) 2 ) _ C 2 H 3 .C 2 H 3 2 ) 
 (C 2 H 5 ) 3 P ) ~~ (C 2 H 5 ) 3 P j 
 
 If this be so, the second stage of the reaction is precisely similar to the decomposi- 
 tion already mentioned of the bromine-compound by heat. 
 
 d. By nascent hydrogen it is converted into bromide of tetrethylphosphonium : 
 
 C 2 H 4 Br 2 > _ C 2 H 5 Br ) A ^ 
 
 (C 2 H 5 ) 3 P( ~~ / r ^2TT5\3-Dr T JJ-L 
 
 e. With derivatives of ammonia, it gives bodies of the type of the second compound. 
 The following bodies have been so obtained. 
 
 C 2 H 4 Br 2 \ C 2 H'Br 2 ) C'H'Br 2 ) C 2 H 4 Br 2 \ C 2 H 4 Br 2 \ C 2 H 4 Br 2 \ &WBj? \ 
 \ t (C 2 H 5 ) 3 P , (C 2 H 5 ) 3 P , (C 2 H 5 )'P ,'(C 2 H 5 ) 3 P , (C 2 H 5 ) 3 P , (C 2 H') 3 P I 
 H 3 N J CH s .H 2 Nj OT*HWj (CH 3 ) 3 N j (CH 3 ) 3 P J (C 2 H 5 ) 3 Pj (C 2 H 5 ) 3 Asj 
 It has already been stated that bodies of this class part with all their bromine to 
 
 O2TT4 TT2 O2 "i 
 
 salts of silver. Hydrate of silver gives 2 [(C 2 H 5 ) 3 P] ( and 8imilar bodies. These 
 
 are strong bases and give the corresponding salts by the action of acids.. M(rrrS\xpi \ 
 
 C 2 H 4 ) 
 is decomposed by heat into /(pjpxsp > a compound already mentioned, and oxide of 
 
 * As rational names for bodies deriving from the mixed type jjjsjjj. namely amic bases and antic 
 acids, the terms hydoramines and hydoramides (not to be confounded with hydramides) may be used 
 (see further, art. NOMENCLATURE). 
 
 O 3 
 
198 AMMONIUM-BASES. 
 
 C 2 H 4 Br 3 
 
 (C 2 H 5 ) 3 P 
 (C 2 H 5 ) 3 As 
 
 C 2 H 4 Br 3 ) 
 
 triethvlphosphine, P(C 2 H 5 ) 3 0. (C 2 H 5 ) 3 P [ is decomposed by heat Into 
 
 j 
 
 triethylarsine, (C 2 H 5 ) 3 As. 
 
 B. ACTION OF TRIATOMIC CHLORIDES, BROMIDES, OR IODIDES : 
 
 1. On Ammonia. 
 
 Tribromide of glyceryl, (C'^H 5 )Br 3 , gives with ammonia a base containing NC 6 H 9 Br 2 , 
 and bromide of ammonium. The reaction probably takes place according to the 
 following stages : 
 
 1 C'H'Br* = C 3 H 4 Br 2 + HBr. 
 
 2 2(C 3 H 4 Br 2 ) + KH S - NC 6 H 9 Br 2 + 2HBr, 
 
 the hydrobromic acid which is formed of course combining with ammonia. The first 
 stage of the reaction is analogous to the conversion of bromide of ethylene into brom- 
 ethylene by the action of alcoholic potash : the compound, C 3 H 4 Br 2 may be regarded 
 as dibrom-propylene, or as bromide of brom-allyl, (C 3 H 4 Br)'Br. In the latter case, 
 
 ((C 3 H 4 Br) 
 the product of its action on ammonia becomes ^J/ngrm.* dibrom-diallylamine. 
 
 (H 
 
 (Maxwell Simpson). 
 
 2. On Primary derivatives of ammonia. 
 
 Chloroform, (CH)C1 3 , reacts on phenylamine, forming the hydrochlorate of a monoacid 
 base, containing, C 13 H 12 N 2 , and which may be considered as representing two molecules 
 
 of phenylamine in which the radicle (($H) replaces H 3 ; thus (cen 
 
 3. On Tertiary derivatives of ammonia. 
 
 lodoform, (CH)I S , combines with three molecules of triethylphosphine, giving 
 j^ { , This compound parts with all its iodine to silver-salts, which accords 
 
 with what is said above respecting the compounds of bromide of ethylene with trie- 
 thylphosphine. Its solution treated with hydrate of silver does not give a correspond- 
 ing hydrate, but hydrate of methyl-triethylphosphonium and oxide of triethylphos- 
 phine. 
 
 + 2[(C 2 IP) 3 P.O] + 3AgI. 
 
 C. ACTION OP TETRATOMIC CHLORIDES, BROMIDES, OR IODIDES ON DERIVATIVES 
 OF AMMONIA. 
 
 !v 
 
 Bichloride of carbon, (C)C1 4 , reacts on phenylamine thus : 
 
 3(CH 7 N) + CC1 4 ~ 3HC1 + C I9 H 17 N 3 .HC1. 
 
 3 mol. pheny- 
 lamine. 
 
 The product of this reaction may be regarded as the hydrochlorate of a base de- 
 riving from three molecules of phenylamine by the substitution of (C) for H 4 : viz. 
 
 ir 
 
 (C) ) 
 (C 6 H 5 ) 3 \ W. 
 ' H 2 J 
 
 (For details, see various papers by Hofmann, Proc. Koy. Soc. vols. ix. and x., also 
 the Articles PHOSPHORUS, ARSENIC, ANTIMONY.) 
 
 AMMONIUM-BASES CONTAINING METALS. A very large number of compounds 
 have been obtained by treating different metallic salts with ammonia. Some of these 
 compounds are apparently of similar constitution to the salts of the organic ammonium- 
 bases, or to easily conceivable derivatives of them. But it is impossible to reduce the 
 greater number of them to any consistent system, before they have themselves been 
 more thoroughly examined, and we have more definite notions as to the atomicity of 
 the metals contained in them. The following are examples of some of these com- 
 pounds which can be written as analogous to known or conceivable organic com- 
 pounds, 
 
AMMONIUM-BASES AMORPHISM. 199 
 
 Metallic Compounds. Organic Analogues. 
 
 KH 3 CuCl N.H 3 .C S H 5 .C1 
 
 NH 2 (Hg)Cl .... N.H 2 (C 2 H 5 ) 2 C1. 
 
 (or N 2 H 4 (Hi) 2 Cl 2 (?) . . . . N 2 H 4 (C 2 H 4 ) 2 .C1. 2 
 
 N(Hg) 2 Cl N(C 2 H 5 ) 4 C1. 
 
 (or N 2 (Hg) 4 Cl 2 (?) .... N 2 (C 2 H 4 ) 4 C1. 2 
 
 NH 3 (Hg)Cl 2 .... 'N(CH 8 ) 8 (C 2 !k 4 ):Br. 
 
 Nrn 2 NfH 2 
 
 O-j(Hg) .... OJ(C 2 H 4 ) (unknown.) 
 ll(Hg) ll(C 2 H 4 ). 
 
 NH 3 (Pt)Cl 2 P(C 2 H 5 ) 3 (C 2/ k 4 )Br 2 . 
 
 N 2 H 6 (Pt)Cl 2 P 2 (C 2 H 5 ) 6 (C 2 'k 4 )Br 2 . 
 
 ***Hg = 200 
 
 The attempts which have been made by some chemists to make formulae for many 
 other metallic derivatives of the ammonium-salts, by supposing ammonium capable of 
 replacing hydrogen in ammonium, or by assuming the existence of such radicles as 
 PtCl or PtO, may be described in words used with reference to another subject, by 
 the author of one such attempt, as " unwissenschaftliche Spielereien, die hier keine 
 Beriicksichtigung verdienen." Or. C. F. 
 
 A.XKXTIOTXC LIQUID. (See ALiANTOic and AMNIOTIC LIQUIDS.) 
 .aireoiBITE. A mineral allied to nickel-glance, and probably identical with it. 
 
 AXVIORPHISIVX. (G m. i. 102.) Solid bodies which do not exhibit any crystalline or 
 regular structure, even in their minutest particles, are said to be amorphous (, privative, 
 and fj.op<t>rj form). Such are opal and other forms of silica, also glass, obsidian, pumice 
 stone, bitumen, resins, coal, albuminous substances, and numerous precipitates. Such 
 bodies have a smooth conchoidal fracture, never exhibiting a granulated appearance on the 
 broken surface ; they have no particular planes of cleavage, such as are found in crystals, 
 but require the same amount of force to separate them in all directions : they also 
 conduct heat equally in all directions, and never exhibit double refraction, excepting 
 when pressed or otherwise brought into a forced state. In short, the essential character 
 of an amorphous body is perfect uniformity of structure in every direction, each particle 
 being similarly related to all those which surround it, the character of a fluid without 
 its mobility, whereas in crystallised or organised* bodies, the molecular forces act with 
 greatest energy in certain lines or axes, thereby determining an arrangement of the 
 particles according to fixed laws, and causing the body to exhibit different degrees of 
 tenacity, elasticity, permeability, refracting power, and conducting power for heat and 
 electricity in different directions. It must not be assumed that a body is amorphous 
 because it does not exhibit a regular shape in the mass : marble and loaf-sugar have 
 no definite external form ; but they consist of aggregates of minute crystals, and when 
 broken, exhibit, not a conchoidal, but a granular fracture. 
 
 The amorphous state is by no means peculiar to certain substances, a great number 
 of bodies being capable of existing both in the amorphous and in the crystalline state. 
 Sulphur, when it solidifies slowly from fusion or solution, forms regular crystals, but 
 when poured in the melted state into cold water, it solidifies in a soft, plastic, viscid 
 mass, capable of being drawn out into threads, and exhibiting no trace whatever 
 of crystalline structure. Phosphorus also assumes a regular crystalline form when 
 slowly cooled from solution in bisulphide of carbon or from fusion, but when cast into 
 moulds and quickly cooled, it forms a waxy solid, having a conchoidal fracture ; and 
 by other modes of treatment to be described hereafter, it may be reduced to a perfectly 
 amorphous red powder. Carbon is crystalline in the diamond and in graphite ; amor- 
 phous in charcoal, lamp-black, and the various other forms which it assumes when 
 
 * The term amorphous is generally used in contradistinction to crystalline alone ; but its proper use 
 is in opposition to regular, whether crystalline or organised: for organic structures exhibit many 
 properties of which amorphous bodies, properly so called, are destitute ; thus wood, according to the 
 researches of Dr. Tjndull, exhibits three distinct axes of cleavage, permeability, elasticity, and con- 
 ducting power for heat. 
 
 o 4 
 
200 AMORPHISM. 
 
 separated from organic bodies by imperfect combustion. Boron and silicon exhibit 
 similar varieties. Arsenious acid, as it collects in the chimneys of furnaces in which 
 arsenical ores are roasted, is a glassy amorphous mass ; but by dissolving it in hot 
 water or hydrochloric acid, and leaving the solution to cool, it is obtained in the cry- 
 stalline form (see ARSENIC). Native sulphide of antimony, which is crystalline, may 
 be rendered amorphous by melting it in a glass tube and plunging the tube into ice- 
 cold water : and by melting it again and cooling slowly, the crystalline structure may 
 be restored. Similar transformations may be effected with native sulphide of mercury, 
 also with the minerals Vesuvian and Axinite, and certain varieties of garnet. Glass, 
 which is perhaps the most characteristic of amorphous bodies, may be devitrified by 
 keeping it for some time in the soft state at a high temperature : it then acquires a 
 crystalline structure and becomes nearly opaque, forming the substance called Keau- 
 mur's porcelain. Generally speaking, rapid cooling from fusion is favourable to the 
 assumption of the amorphous structure, while crystallisation is promoted by slow cool- 
 ing, the particles then having time to arrange themselves in a definite manner. It is 
 a^o true to a great extent that bodies which pass at once from the perfectly fluid to 
 the solid state, water, for instance, crystallise on solidifying, whereas those which 
 pass through the viscous form, like glass, solidify in the amorphous state ; to this, how- 
 ever there are some striking exceptions : thus sugar, the solution of which is ex- 
 tremely viscid when concentrated, solidifies by slow evaporation in crystals of great 
 size and regularity. 
 
 The passage from the amorphous to the crystalline state sometimes takes place 
 spontaneously, the body all the while remaining solid. Vitreous arsenious acid, which, 
 when recently prepared, is perfectly transparent, becomes turbid when left to itself for 
 a few months, and subsequently white and opaque. Sugar which has been melted in 
 the form of barley-sugar is in the vitreous state, but after a while acquires a crystal- 
 line structure and becomes opaque. These phenomena show that the molecules of 
 bodies, even in the solid state, possess a certain freedom of motion. 
 
 The change from the amorphous to the crystalline condition, or the contrary, is 
 generally accompanied by an alteration of other physical properties. Bodies are for 
 the most part denser and less soluble in the crystalline than in the amorphous state, 
 and have less specific heat. Vesuvian, which crystallises in square prisms of specific 
 gravity about 3*4, and garnet, which occurs in rhombic dodecahedrons of specific 
 gravity 3*63, both form by fusion and subsequent cooling, transparent glasses whose 
 specific gravity is about 2*95, so that, in passing from the crystalline to the amorphous 
 state, garnet suffers an expansion of about ^ and vesuvian of y. The glass also dis- 
 solves readily in hydrochloric acid, whereas the crystallised minerals are quite 
 insoluble. Many other crystalline siliceous minerals not soluble in acids become so 
 by fusion, probably from the same causes. Quartz, which is crystallised silica, is 
 much harder and denser than opal, which is the same chemical compound in the 
 amorphous state. Quartz-powder dissolves but very slowly in boiling potash-ley and 
 is quite insoluble in that liquid when cold, whereas pulverised opal is gradually dis- 
 solved at ordinary temperatures and in a few minutes at the boiling heat. A remark- 
 able exception to the general rule is, however, presented by arsenious acid, which is 
 both less dense and more soluble in the crystalline than in the vitreous state. 
 
 Another difference first observed by Graham is, that bodies have greater specific 
 heat in the amorphous than in the crystalline state. Ordinary phosphate of sodium 
 (P0 4 Na 2 H) solidifies from fusion in the vitreous state ; the corresponding arsenate in 
 the crystalline form : now the former in solidifying gives out perceptibly less heat in 
 a given time than the latter, a greater portion of the latent heat of fusion appearing to 
 be retained by it. Connected with this law is the remarkable phenomenon of incan- 
 descence which many bodies exhibit when their temperature is gradually raised. 
 Hydrated oxide of chromium if heated merely to the point at which it parts with its 
 water, remains nearly as soluble in acids as before, but if the heat be raised nearly to 
 redness, the oxide suddenly becomes incandescent, and is afterwards found to be much 
 denser and nearly insoluble in acids. Similar phenomena are exhibited by alumina 
 and zirconia. Gadolinite (silicate of yttrium) which in its natural state exhibits a 
 conchoidal fracture and obsidian-like appearance, becomes vividly incandescent when 
 moderately heated, and is afterwards found to dissolve but very imperfectly in hydro- 
 chloric acid, although before ignition it is very easily soluble ; its density increases at 
 the same time, though its absolute weight remains unaltered. Vitreous arsenious 
 acid also sometimes exhibits incandescence in passing from the amorphous to the crystal- 
 line state. When a solution of the vitreous acid in hot hydrochloric acid is left to 
 cool in the dark, the formation of every crystal is accompanied by a flash of light ; but a 
 solution of the crystalline acid, under the same circumstances, exhibits no light what- 
 ever. 
 
AMPELIC ACID AMYGDAL1N. 201 
 
 AMPEXiZC ACID. An acid isomeric with salicylic acid, C 7 H 6 3 , obtained in 
 small quantity by the action of strong nitric acid upon those schist-oils which boil 
 between 80 and 150 C. Picric acid and a flocculent matter are formed at the same time. 
 Ampelic acid is a white substance, without odour, nearly insoluble in cold water, but 
 little soluble in boiling water. Its solution reddens litmus. Boiling alcohol and ether 
 dissolve it readily, and on cooling deposit it in the form of a powder, having a scarcely 
 perceptible crystalline character. Saturated with ammonia, it exhibits the following 
 reactions. With chloride of calcium, a white precipitate, which does not form when 
 hot ; the mixture deposits crystals on cooling. No precipitate with the chlorides of 
 barium, strontium, manganese, or mercury. A green precipitate with acetate of 
 nickel ; blue with acetate of copper ; and white with acetate and nitrate of lead. 
 (Laurent, Ann. Ch. Phys. [2] Ixiv. 325.) 
 
 AMPEXiXXa*. A substance resembling creosote, obtained from that portion of 
 schist-oil which boils between 200 and 280 C. The oil is shaken up several times 
 with strong sulphuric acid, then mixed with -^ or ^ of its bulk of aqueous potash, and 
 the liquid is left at rest for a day. The lower watery layer of liquid is then separated 
 from the upper oily layer, and shaken up with dilute sulphuric acid, and the oil which 
 rises to the surface is removed with a pipette, and gently heated with 10 or 20 times 
 its bulk of water, which dissolves the ampelin, leaving a small quantity of oil. On 
 separating this oil, and adding a few drops of sulphuric acid to the aqueous solution, 
 the ampelin rises to the surface in the form of an oil, having a slight brownish tint. 
 
 Ampelin dissolves in 40 or 50 times its volume of water, and is separated from the 
 solution by a few drops of sulphuric or nitric acid, even when very dilute. Potash, soda, 
 and their carbonates render the solution slightly turbid at the first instant, but it recovers 
 its transparency when heated. Carbonate of ammonium renders it permanently turbid. 
 Chloride of sodium or chloride of ammonium added to a solution of ampelin in caustic 
 potash or carbonate of potassium separates the ampelin, which is then not redissolved 
 on heating the liquid. Ampelin dissolves in alcohol, and in all proportions in ether. 
 It does not solidify at 20 C. It is decomposed by distillation, yielding water, a light 
 oil, and charcoal. Boiling nitric acid attacks it strongly, producing oxalic acid, and 
 an insoluble viscous substance. (Laurent, Ann. Ch. Phys. [2] Ixiv. 321.) 
 
 AXVIPHXBOXiE and AMPHIBOIiITE. (See HORNBLENDE.) 
 
 AftXPHlX) SAINTS. A name applied by Berzelius to salts which, according to 
 his views, are compounds of two oxides, sulphides, sclenides, or tellurides, e. g. sulphate 
 of copper, Cu 2 O.S0 3 ; sulpharsenate of potassium, 3K 2 S.As 2 S 5 ; sulphantimonate of 
 sodium, 3Na 2 S.Sb 2 S 5 , &c., such salts containing three ultimate elements in contra- 
 distinction to the haloid-salts, namely, the chlorides, bromides, iodides, &c., which 
 are binary compounds of the first order, containing only two elements, such as chloride 
 of sodium, NaCl, iodide of silver, Agl, &c. It is evident that the so-called amphid 
 salts are those which belong to the water-type, e. g. nitrate of copper, Cu 2 O.N 2 5 = 
 
 J 2 Sulpharsenate of potassium, 3K 2 S.As 2 S 5 = -S'j^?)'", whereas the haloid- 
 compounds belong to the type HH or HC1. 
 
 AIMPHIG-EZtfE. See LETJCITE. 
 
 AMP HILO CITE. See DiDBiMiTE. AMPHODEXXTE. See ANOBTHITE. 
 
 AXVEYGX>AX.XC ACID, C 20 H 26 12 . Produced by the metamorphosis of amygdalin 
 under the influence of alkalis. Amygdalin dissolves in cold baryta-water without 
 decomposition, but on boiling the mixture, ammonia is disengaged. The ebullition is 
 continued until the liberation of ammonia ceases altogether; a current of carbonic 
 acid ia then passed through the liquid, to precipitate the excess of baryta ; and the 
 acid is finally liberated from the barium-salt by cautious precipitation with sulphuric 
 acid. It is a slightly acid liquid, which dries up to a gummy mass, insoluble in 
 absolute alcohol, cold or boiling, and insoluble in ether. Boiled with a mixture of 
 peroxide of manganese and sulphuric acid, it yields formic and carbonic acids and hydride 
 of benzoyl. Its salts are not well defined ; they are more or less soluble in water 
 (Liebig and Wohler, Ann. Ch. Pharm., Ixiv. 185.) 
 
 Amygdalate of ethyl is obtained, according to Wohler, by dropping a mixture of 
 alcohol and amygdalin into hydrochloric acid gas. (Wohler, Ann. Ch. Pharm. Ixvi. 
 
 AMYGDAliisr, C 2 H 27 NO + 3IPO. A crystalline principle existing in bitter- 
 almonds, the leaves of the Ccrasus lauro-ccrasus, and many other plants, which by 
 isolation yield hydrocyanic acid. The bitter-almond oil and hydrocyanic acid do 
 not exist ready formed in these plants, but are the result of the decomposition of 
 umygdaJm under the influence of enmlsin, a nitrogenised fermentable principle existin" 
 with it in the plant. 
 
202 AMYL. 
 
 To prepare amygdalin, the oil is expressed from the paste of bitter-almonds, and 
 the residual mass extracted with boiling alcohol. This alcoholic solution is rendered 
 turbid by the presence of globules of oil, which are allowed to collect and separated by 
 decantation; it is then evaporated to half its original volume, and the amygdalin 
 separated by the addition of ether, in which it is insoluble. The precipitated amyg- 
 dalin is pressed between folds of bibulous paper, washed with ether, and finally crys- 
 tallised from concentrated boiling alcohol. (Liebig and Wohler.) 
 
 Amygdalin crystallises in white scales having a pearly lustre, insoluble in ether, but 
 very soluble in water, from which it crystallises in thin transparent prisms containing 
 3 atoms of water of crystallisation. Its aqueous solution has a slightly bitter taste. 
 It deflects the plane of polarisation of a ray of light to the left : [a] = 3 5 '51. The 
 change which amygdalin undergoes by the action of emulsin (and other albuminous 
 vegetable principles), is expressed by the following equation : 
 
 C 20 H 27 N0 11 + 2H 2 = C 7 H 6 + CNH + 2C 6 H 12 
 
 Amygdalin. Hydride Hydro- Glucose, 
 
 ofbenzoyl. cyanic 
 acid. 
 
 By distillation with nitric acid, or other oxidising agents, it is resolved into am- 
 monia, hydride of benzoyl, benzoic, formic, and carbonic acids. Caustic alkalis con- 
 vert it into amygdalic acid. 
 
 It is a neutral body, forming compounds neither with acids nor with alkalis. 
 
 AlVTYL, C 5 H", or C 10 H 22 . (Gm. xi. pp. 183; Gerh. ii. pp. 675 708). The 
 fifth term of the series of alcohol-radicles, OH 2n+1 . The alcohol in an impure state 
 (potato-fusel oil), appears to have been first noticed by Scheele ; and has been inves- 
 tigated, together with its derivatives, by Pelletan (J. Chim. med. i. 76, also Ann. 
 Ch. Phys. [2] xxx. 200), Dumas (Ann. Ch. Phys. [2] Ivi. 314; Dumas and Stas, 
 Ann. Ch. Phys. [2] Ixxiii. 128); Cahours (Ann. Ch. Phys. [2] Ixx. 81, Lev. 193); 
 and Balard, Ann. Ch. Phys. [3] xii. 294). The radicle itself was isolated by Frank- 
 land in 1849. (Chem. Soc. Qu. J. iii. 307 ; Ann. Ch. Pharm. Ixxiv. 41.) 
 
 Amyl in the free state, C 10 H 22 = C'lF.C 5 !! 11 , is prepared by the action of zinc- 
 amalgam upon iodide of amyl, the reaction being completed by the addition of potas- 
 sium (Frankland). 2. By the action of sodium upon iodide of amyl (Wurtz). 
 3. By the electrolysis of caproate of potassium (Brazier and Gossleth). 4. By the 
 destructive distillation of certain kinds of coal (Greville Williams). 
 
 (1.) Pasty zinc-amalgam is brought into the copper cylinder used in the preparation 
 of zinc-ethyl (see ETHYL) : the cylinder is then half filled with granulated zinc and 
 iodide of amyl is added. After gently warming to expel the air, the cylinder is closed 
 
 temperature. To obtain the amyl, 
 the cylinder is heated in a water-bath at 80 C., whereupon amylene and hydride of 
 amyl pass over. On applying the heat of a naked flame, amyl distils over, and may 
 be purified by one rectification. (Frankland.) 
 
 (2.) Iodide of amyl is warmed with sodium, and distilled; the product again dis- 
 tilled from sodium and rectified, the portion which passes over at 158 C. being collected 
 apart. (Wurtz, Ann. Ch. Phys. [3] xliv, 275.) 
 
 (3.) A concentrated solution of caproate of potassium is submitted to the electrolytic 
 action of six zinc-carbon elements, the platinum poles being separated by a porous 
 diaphragm. Amyl collects upon the surface of the liquid surrounding the negative 
 pole : it is distilled from alcoholic caustic potash and washed with water. (Brazier 
 and Gossleth, Chem. Soc. Qu. J. iii. 221.) 
 
 (4.) Bog-head naphtha is submitted to fractional rectification, the portion boiling be- 
 tween 154 169 C. being collected apart, and the product thus obtained is submitted 
 to the action of fuming nitric acid, the action of the acid being checked by cold. The 
 mixture on standing separates into two layers, the upper of which is again shaken 
 with nitric acid. The product which has remained unacted upon is washed with 
 caustic soda and water successively, dried with solid caustic potash, and distilled over 
 sodium. The resulting liquid is again rectified at 157 160 C. (C. Greville 
 Williams, Phil. Trans. 1857, 447.) 
 
 Amyl is a transparent colourless liquid, of agreeable smell and burning taste. 
 Specific gravity, 0'77 at 11 C. Boiling-point 155 159 C. Vapour-density 4'90. It 
 is miscible with alcohol, immiscible with water. Amyl is not acted upon by fuming sul- 
 phuric acid ; it is slowly attacked by nitric and nitro-sulphuric acids, and decomposed 
 after long digestion with pentachloride of phosphorus. 
 
 BROMIDE OF AMYL. Prepared by the action of bromine and phosphorus upon 
 amylic alcohol (Cahours, Ann. Ch. Phys. [2] Ixx. 98). In three flasks are placed respec- 
 
AMYL. 203 
 
 lively 15 pts. of amylic alcohol, 2^ pts. of bromine, and 1 pt. of phosphorus. A little 
 of the bromine is added to the amylic alcohol, and the latter is poured upon and 
 digested with the phosphorus to decoloration. It is then poured into its own flask, 
 and a little more bromine is added. The process is repeated, and the final product is 
 washed with water, dried, and rectified. 
 
 Bromide of amyl is a transparent colourless liquid, heavier than water. It has an 
 alliaceous odour and sharp taste. It is soluble in alcohol, insoluble in water. De- 
 composes by boiling with alcoholic caustic potash. 
 
 CHLORIDE OF AM YL, CWCL Obtained by the action of strong hydrochloric acid 
 upon amylic alcohol (Balard, Ann. Ch. Phys. [3] xii. 294) ; also by the action of penta- 
 chloride of phosphorus upon amylic alcohol. (Cahours.) 
 
 Preparation. 1. Amylic alcohol is heated in a retort to 110 C., a rapid current of 
 hydrochloric acid being passed through the tubulus into the amylic alcohol; the 
 chloride of amyl as it is formed distils over. When the retort is nearly empty the 
 distillate is poured back, and the same process repeated (Guthrie). The product is 
 then shaken with strong hydrochloric acid, in which amylic alcohol is soluble, chloride 
 of amyl insoluble, then with water. 
 
 2. Amylic alcohol is distilled with its own weight of pentachloride of phosphorus, 
 washed, dried, and rectified. 
 
 Chloride of amyl is a colourless, transparent, neutral liquid, of agreeable odour. It 
 boils at 101 C. Vapour-density, 3'8. Burns with a luminous flame bordered with 
 green. 
 
 Chlorine acts upon chloride of amyl, giving rise to substitution-products, which go 
 as far as C 5 H 3 C1 8 C1. 
 
 CYANIDE OF AMYL. See CYANIDES. 
 
 HYDRATE OF AMYL, or AMYL- ALCOHOL, C 5 H 12 = C5 ^ n Jo [or C^W O 2 = 
 
 C l H n O.HO]. Amylate of Hydrogen. Hydrate of Amyl. Hydrate of Pentyl. Hy- 
 dratcd Oxide of Amyl. Fusel-oil. This alcohol seems invariably to accompany ethyfio 
 alcohol (see ALCOHOLS, p. 97) when the latter is formed by fermentation. The conditions 
 of its formation are unknown ; it seems, however, to occur in largest quantity in those 
 liquids which remain most alkaline during fermentation. In the distillation of vege- 
 table juices which have been fermented, the latter portions of the distillate contain 
 water, ethylic, propylic (?) butylic and amylic alcohols, besides the acids and aldehydes 
 of these alcohols and probably higher fatty acids and aldehydes. To obtain the pure 
 amylic alcohol from the crude product, it is shaken several times with hot milk of lime, 
 decanted, dried over chloride of calcium, and rectified at 132C. 
 
 Amylic alcohol is a transparent colourless liquid having a peculiar odour (the peaty 
 smell of whisky is due to its presence in small quantities), which causes coughing, and 
 burning taste. It burns with a white smoky flame. Solidifies at about 22 C. 
 Specific gravity O'Sll at 19 C: Boiling-point 132 C. Vapour-density 3'147. 
 Soluble in common alcohol and ether, nearly insoluble in water. It dissolves small 
 quantities of sulphur and phosphorus. 
 
 According to Pasteur (Compt. rend. xli. 296), ordinary amylic alcohol is a mixture 
 of two amylic alcohols identical in chemical composition and vapour- density, but 
 differing in their optical properties, one of them turning the plane of polarisation of a 
 ray of light to the left, while the other is opticially inactive. A difference of solubility in 
 some of the salts obtained from the mixed alcohols, furnishes the means of their separa- 
 tion ; the active amyl-sulphate of barium is 2| times more soluble in water than the 
 corresponding inactive salt. The optical rotatory power of amylic alcohol varies, on 
 account of its being a variable mixture of these two modifications. This difference in 
 the two amylic alcohols is said to be traceable in some other of their derivatives, e. g. 
 caproic acid prepared from active cyanide of amyl, rotates the plane of polarisation. 
 (Wurtz.) 
 
 Decompositions of Amyl-alcohol. 1. By heat. The vapour of amyl-alcohol passed 
 through a glass tube heated to dull redness, is resolved into tritylene (propylene) 
 marsh-gas and other hydrocarbons. (Eeynolds.) 
 
 2. By oxidation. Amyl-alcohol is difficult to set on fire, and burns with a white 
 smoky flame. In contact with the air at ordinary temperatures, it is very slowly 
 oxidised and acquires a slight acid reaction. The oxidation is greatly accelerated by 
 the presence of platinum-black, the amyl-alcohol being then converted into valeric 
 acid : 
 
 C 5 H I2 + O 2 = C 5 H 10 2 + H 2 0. 
 
 Amyl-alcohol distilled with a mixture of sulphuric acid and peroxide of manganese or 
 bichromare of potassium, yields valeric aldehyde, valeric acid, and valerate of amyl. 
 The same products, together with nitrite of amyl and hydrocyanic acid, are formed 
 by the action of nitric acid. Amyl-alcohol is also converted into valeric acid by heat- 
 
204 AMYL. 
 
 ing it to 220 C. with a mixture of lime and hydrate of potassium, hydrogen gas being 
 evolved : 
 
 C 5 H 12 + KHO = C 5 H 9 K0 2 + 4H. 
 
 Amyl- Valerate of 
 
 alcohol. potassium. 
 
 3. By sulphuric acid. Amyl-alcohol mixes readily with strong sulphuric acid, forming 
 a red liquid, which contains amylsulphuric acid, S0 4 .C 5 H '.H, as well as free sulphuric 
 acid. On distilling the mixture, the amyl-alcohol is dehydrated, and amylene, C 5 H 19 
 passes over, together with the polymeric compounds, C'H 20 and C*H 40 , and perhaps 
 also amylic ether, (C 5 H n ) 2 ; at the same time, however, a portion of the alcohol is 
 oxidised and converted into valeric aldehyde and valeric acid, sulphurous acid being 
 evolved and a black pitchy mass remaining in the retort. 
 
 4. With phosphoric acid, amyl-alcohol yields amyl-phosphoric acid, P0 4 .C 5 H U .H 2 . 
 Distilled with phosphoric anhydride, it is converted into amylene and its nmltiples. 
 
 5. Trichloride of phosphorus converts amyl-alcohol into phosphite of amyl, amyl- 
 phosphorous acid, chloride of amyl, and hydrochloric acid : 
 
 3(C 5 H.H.O) + PCI 3 = P0 3 .(C s H n ) 2 .H + C 5 H n Cl + 2HC1. 
 
 Phosphite of amyl. 
 
 and 3(C 5 H n .H.O) + PCI 3 = P0 3 .C 5 H n .H 2 + 2C 5 HC1 + HC1. 
 
 Amylphosphorous 
 acid. 
 
 6. With pentachloride of phosphorus, amyl-alcohol forms chloride of amyl, hydro- 
 chloric acid, and chlorophosphoric acid, or, when the amyl-alcohol is in excess, diamyl- 
 phosphoric acid : 
 
 C 5 H U .H.O + PCI 5 = C 5 H"C1 + HC1 + POC1 3 
 
 Chlorophos- 
 phoric 
 acid. 
 
 and 9(C 5 H IJ .H.O) + 2PC1 5 = 5C 5 HC1 + 5HC1 + 2[P0 4 .(C 5 H n ) 2 .H] + H 2 0. 
 
 Diamylphosphoric 
 acid. 
 
 7. Chlorine-gas is absorbed in large quantity by amyl-alcohol and forms chloramylal, 
 a compound homologous with chloral. 8. Amyl-alcohol absorbs hydrochloric acid gas 
 and mixes with the concentrated aqueous acid ; on heating the mixture chloride of amyl 
 is formed. 9. It dissolves, with the aid of heat, in a concentrated aqueous solution of 
 chloride of zinc, forming a liquid which boils at 130C., and yields a distillate of amylene 
 and its multiples. 10. Distilled with phosphorus and bromine or iodine, it yields 
 bromide or iodide of amyl. 11. Distilled with fluoride of boron, or fluoride of silicon. 
 it yields amylene and its multiples, but little or no oxide of amyl. 11. Phosgene gas 
 is abundantly absorbed by amyl-alcohol, forming chloroformate of amyl, and the liquid 
 when distilled yields carbonate of amyl (Medlock) [with evolution of phosgene (?)] 
 
 C'ff'.H.O + COOP = CC10 2 .C 5 H + HC1. 
 
 Phos- Chloroformate 
 gene. of amyl. 
 
 and 2(CC10 2 .C 5 H) = C0 8 .(C 5 H) 2 + COC1 2 [?] 
 
 Carbonate of 
 amyl. 
 
 Carbonate of amyl is also obtained by adding water to the solution of phosgene in 
 amyl-alcohol (M e d 1 o c k) : 
 
 2(CC10 2 .C*H 11 ) + H 2 = C0 3 .(C 5 H) 2 + 2HC1 + CO 2 . 
 
 21. Disulphide of carbon, in presence of potash, converts amyl-alcohol into amylsul- 
 phocarbonic or amylxanthic acid (p. 206). 13. Chloride of cyanogen is rapidly 
 absorbed by amyl-alcohol, and forms products similar to those which it yields with 
 ethyl-alcohol. 
 
 C 5 H 12 O + CNC1 + H 8 = C 6 H 13 N0 2 + HC1. 
 
 Amyl- Amyl-ure- 
 
 alconol. thane. 
 
 14. Potassium (and sodium) decomposes amyl-alcohol in the same manner as ethyl 
 alcohol, forming amylate of potassium, C 5 H M KO with evolution of hydrogen. 
 
 Amyl-alcohol combines with a few metallic chlorides in the same manner as ethyl- 
 alcohol. With chloride of calcium and dichloride of tin, it forms crystalline com- 
 pounds which are decomposed by water. It dissolves in caustic potash and soda. 
 
 HYDEIDE OF AMYL, C 5 H".H. Iodide of amyl is heated -with zinc and its own 
 volume of water for a few hours to 142 C. in a copper cylinder (see zinc-ethyl), and 
 the contents are distilled from a water bath at 60. The distillate consists principally 
 of amylene and hydride of amyl. The mixture is left for 24 hours in contact with 
 
AMYL. 205 
 
 caustic potash, and again rectified from a water-bath at 35. The distillate is 
 immersed in a freezing mixture and treated with a mixture of anhydrous and fuming 
 siilphuric acid, which retains the amylene. Lastly, the hydride of amyl is distilled 
 from a water-bath (Frankland, Ann. Ch. Pharm. Ixxiv. 41). Colourless transparent 
 liquid, having a pleasant odour. Specific gravity 0-638, at 14 C. Boiling-point 
 30 C. Vapour-density 2'382. 
 
 IODIDE OF AMYL, C 5 H n I. Prepared by the action of iodine and phosphorus upon 
 amylic alcohol (Cahours, Ann. Ch. Phys. [2] Ixx. 81). Four parts of iodine are 
 placed in one flask, and excess of phosphorus in another. Seven parts of moist amylic 
 alcohol are poured upon the iodine, the liquid shaken till opacity is produced, then 
 poured upon the phosphorus and digested till the colour is removed again poured 
 upon the iodine, and so on, till all the iodine is exhausted. The nearly colourless 
 product so obtained, is washed with slightly alkaline water, dried over chloride of 
 calcium and rectified. The latter portions are the purest. 
 
 Iodide of amyl is a colourless transparent liquid of faint odour and pungent taste. 
 Specific gravity 1-511 at 11 C. Boiling-point 146. Vapour-density 6'675. It turns 
 brown on exposure to light. 
 
 OXIDE OF AMYL, C^H^O = (C 5 H n ) 2 [or G) fl0]. Amylic ether. Amylate 
 of Amyl. Prepared by the action of sulphuric acid on amyl-alcohol. Strong 
 sulphuric acid is heated to 150 C. in a retort, and amyl-alcohol allowed to enter 
 slowly through the tubulus ; the distillate is then shaken with carbonate of sodium, 
 washed and rectified. 2. By the action of amylate of potassium on iodide of amyl. 
 Amylate of potassium is digested in a retort connected with an inverted con- 
 denser, with an equivalent quantity of iodide of amyl, and the product is distilled and 
 rectified. 3. By the dry distillation of amylsulphate of calcium (Kekule). Oxide 
 of amyl boils at about 180 C. It is colourless and of agreeable odour. 
 
 Oxide of Amyl and Ethyl, C 7 H I6 = C 2 H 5 .C 5 H n .O. Amylate of Ethyl, Ethylate 
 of Amyl, Ethylamylic Ether. Prepared by the action of amylate of potassium upon 
 iodide of ethyl, or of iodide of amyl upon ethylate of potassium. ( W illiamson, Chem. 
 Soc. Qu. J. iv. 103, 234.) (1.) A known weight of potassium is dissolved in absolute 
 alcohol in a tubulated retort ; iodide of amyl is added in sufficient quantity for there 
 to be rather less than 1 at. of iodine for every at. of potassium in the ethylate of 
 potassium ; the retort is connected with an inverted condenser ; and the contents 
 are digested for some time. After distillation, water is added, and the liquid which 
 separates out is dried and rectified. (2.) Iodide of ethyl is added to a hot solution 
 of potash in amylic alcohol, digested &c., as in 1 (G-uthrie). Amylate of ethyl is 
 a colourless transparent liquid of agreeable odour, similar to that of sage. It is 
 lighter than water. Boiling-point 112 C. Vapour-density 4'04. 
 
 Amylate of Methyl, or Methylate of Amyl, CH 14 = CH 3 .C 5 H u .O,is prepared in 
 the same manner as (1) amylate of ethyl (Williamson). Boils at 92 C. Vapour- 
 density 374. 
 
 Amylate of Potassium, C^IP'KO. On bringing freshly cut potassium into dry 
 amylic alcohol, the potassium is dissolved and hydrogen is evolved. To obtain this 
 body in a state of purity, the action is aided by heat until the mass becomes viscid. 
 Any globules of metal which have remained unacted upon are removed, and the pro- 
 duct is poured upon a cold slab, and allowed to solidify. It is then strongly pressed 
 between many folds of bibulous paper to remove the unaltered amylic alcohol. 
 
 Amylate of potassium is a crystalline white body, soapy to the touch, and alkaline 
 to the taste. It is soluble in the alcohols. By water it is instantly converted into amylic 
 alcohol and hydrate of potassium. 
 
 Amylate 0/s0dmm,C 5 H 11 NaO. Closely resembles amylate of potassium. 
 
 SULPHIDES OF AMYL. Protosulphide of Amyl. (C 5 H") 2 S or C 10 H 22 S. 
 Equivalent quantities of amylsulphate and monosulphide of potassium are intimately 
 mixed in a retort (by solution and evaporation) and distilled (B a lard, Ann. Ch. Phys. 
 [3] xii. 248). Colourless liquid of offensive odour. Boiling-point 216 C. Vapour- 
 density 6-3. 
 
 Disulphide of Amyl, C 5 H n S. Obtained by distilling together amylsulphate and 
 disulphide of potassium (0. Henry, Ann. Ch. Phys. [3] xxv. 246). Amber-coloured 
 liquid. Boiling at about 250. Specific gravity -918 at 18 C. 
 
 Sulphide of Amyl and Hydrogen: Amyl-mercaptan, C 5 H n .H.S [or C 19 IP 1 S.HS.'\ 
 Prepared by saturating caustic potash with sulphuretted hydrogen, adding the 
 product to crude amylsulphate of potassium (prepared by mixing equal weights of 
 amylic alcohol and sulphuric acid, neutralising with carbonate of potassium and filter- 
 ing) and distilling from a capacious retort in a chloride of calcium bath. The oily 
 drops in the distillate are washed, dried, and rectified (Kreutzsch, J. pr. Chem. 
 xxxi. 1). Colourless liquid of intolerable odour. It is soluble in alcohol and ether, 
 
206 AMYL. 
 
 but insoluble in water. Specific gravity 0-845 at C. Boiling-point about 120 C. 
 Vapour-density 3-631. It combines with metallic oxides. 
 
 Amylmercaptide of mercury is obtained as a colourless liquid on bringing amyl- 
 mercaptan in contact with mercuric oxide. The mixture solidifies to a solid mass on 
 cooling. The compound is insoluble in water, but soluble in boiling alcohol. The 
 other amylmercaptides are not distinctly known. 
 
 Sulphide of Carbonyl, Amyl, and Hydrogen. Amylsulphocarbonic acid. 
 Amylxanthic acid. C 6 H 12 S 2 = QSJJU -g-f S. The free acid is prepared from the 
 
 potassium-salt by treating the aqueous solution of the latter with dilute hydrochloric 
 acid (Balard, Ann. Ch. Phys. [3] xii. 307). Light yellow oily liquid, of penetrating 
 odour, heavier than water, acid to test paper. It is quickly decomposed by water. 
 
 Amylxanthate of potassium, C 6 H U .K.S 2 0. A cold saturated solution of hydrate of 
 potassium in amylic alcohol, is treated with bisulphide of carbon until the alkaline 
 reaction has disappeared, and the yellow crystals of the potassium-salt which separate 
 out on cooling, are washed with ether, and dried between blotting paper. 
 
 The ethyl and methyl salts of amylxanthic acid, are formed by digesting equivalent 
 quantities of ethylsulphate or methylsulphate of potassium, with amylsulphocarbonate 
 of potassium. They are oily liquids lighter than water. (Johnson, Chem. Soc. Qu. J. 
 v. 142.) 
 
 Dioxysulphocarbonate of Amyl, C 6 H"S 2 0. The compound so-called, which contains 
 1 at. hydrogen less than amylxanthic acid, is produced by the action of iodine 
 on amylxanthate of potassium. It is an oily liquid which boils at 187 C, undergoing 
 decomposition at the same time, and yielding among other products amylxanthate of 
 amyl, CS 2 0.(C 5 H n ) 2 . Digested with aqueous ammonia, it yields amylxanthate of 
 
 ammonium, and xanthamylamide or sulphocarbamate of amyl, ^ ~) J^j I ~. 
 2CH"S 2 + 2NH 3 = CS 2 O.C 5 H".NH 4 + C 6 H 13 NSO + S. 
 
 Amylxanthate of Xanthamy- 
 
 ammonium. lamide. 
 
 The last mentioned compound, xanthamylamide, is a yellow neutral oil, which boils 
 at 184 C. but not without decomposition, being resolved by distillation into amyl- 
 mercaptan and cyanuric acid : 
 
 3C 6 H I3 NSO = 3C S H 12 S -f C 3 N 3 H 3 S . 
 
 Heated on platinum foil, it burns with a yellow luminous flame, giving off white 
 vapours. Boiled with hydrate of barium, it is resolved into amyl-alcohol and sulpho- 
 cyanide of barium : 
 
 C 6 H 13 NSO + BaHO = C 5 H 12 -t- CNSBa + H 2 0; 
 similarly with potash. It is decomposed by chlorine and by nitric acid. 
 
 Xanthamylamide is insoluble in water, but dissolves readily in alcohol and ether. 
 It unites with chloride of mercury, forming the compound C 6 H 13 NS0.4HgCl, which 
 crystallises in white feathery crystals. With dichloride of platinum dissolved in 
 water, it forms a yellow precipitate. (M. W. Johnson, Chern Soc. Qu. J. v. 142.) 
 
 Amysulphocarbamic acid, C 6 H 13 NS 2 (see next page). 
 
 TELLURIDE OF AMYL, or TEI.LUBAMYL, (C 5 H u ) 2 .Te. has been obtained in 
 an impure state by distilling telluride of potassium with amylsulphate of calcium. 
 It is a liquid having a strong disagreeable odour, and boiling at about 198 C. but 
 decomposing at the same time, and depositing tellurium in small shining prisms. By 
 exposure to the air it is converted into a white mass. The nitrate of telluramyl 
 is a colourless heavy oil, obtained by heating telluramyl with moderately strong nitric 
 acid. Treated with the bromide, chloride, or iodide of hydrogen or sodium, it yields 
 the corresponding compounds of telluramyl in the form of viscid heavy oils. The 
 chloride treated with oxide of silver, yields oxide of telluramyl in the form of an oily 
 liquid soluble in water, and so strongly alkaline that it separates ammonia from sal- 
 ammoniac. It forms a crystalline salt with sulphuric acid. (Wohler and Dean, Ann. 
 Ch. Pharm. xcvii. 1.) F. OK 
 
 AMYLAMINE, C 5 H 13 N = C 5 H n .H 2 .N. Amylammonia, Amylia. This organic base 
 is formed: (1.) By heating cyanate orcyanurate of amyl with caustic potash (Wurtz. 
 Ann. Ch. Phys. [3] xxx. 447) : 
 
 CNO.C 5 H n H- 2KHO = C 5 H 13 N + CO 3 K 2 . 
 
 Cyanate of Hydrate Am via- Carbonate 
 
 amyl. ofpotas- mine. ofpotas- 
 
AMYLAMINES. 207 
 
 (2.) In the destructive distillation of animal substances (Anderson). (3.) By heat- 
 ing amylsulphate of potassium with alcoholic ammonia to 250 C. (B e r t h e 1 o t ). (4. ) 
 By the dry distillation of leucine, carbonic anhydride being at the same time evolved 
 (Schwanert, Ann. Ch. Pharm. cii. 221): 
 
 CO 2 
 
 Leucine. Amyla- 
 
 mine. 
 
 Also by carefully distilling a solution of horn in strong caustic potash, leucine being 
 then formed and afterwards decomposed as above (S c hwan ert). (5.) By the action 
 of caustic potash on flannel, tetrylamine being also found among the products. (Grr. 
 Williams, Chem. Gaz. 1858, 310.) 
 
 Preparation. Cyanate or cyanurate of amyl (obtained by distilling cyanate of 
 potassium with amylsulphate of potassium) is distilled with strong caustic potash ; 
 the distillate is neutralised with hydrochloric acid, evaporated and recrystallised ; 
 and the hydrochlorate of amylamine decomposed by distillation from lime and rectified 
 over hydrate of barium. Colourless liquid. Specific gravity 075 at 18 C. Boiling- 
 point 94 C. Amylamine precipitates most metallic oxides which are precipitable 
 by ammonia ; it redissolves alumina. 
 
 Carbonate of amylamine is formed as a crystalline solid, when its base is exposed to 
 the carbonic acid of the air. Hydrobromate of amylamine, C 5 H 13 N.HBr, or bromide 
 of amylium, C 5 H 14 NBr, is formed by adding hydrobromic acid to the base. Hydro- 
 chlorate of amylamine, C 5 H 13 N.HC1 or chloride of amylium, C 5 H 14 NC1, forms' with 
 dichloride of platinum a double salt, C 5 H 14 NCl.PtCl 2 , which is soluble in boiling water. 
 
 Amylsulphocarbamate of Amylium, C n H 2B N 2 S 2 = ' 5 j S' is P roduced 
 
 by the union of 2 molecules of amylamine with 1 molecule of bisulphide of carbon : 
 (C n H 26 N 2 S 2 = 2C 5 H 13 N + CS 2 ). The mixture of the two substances becomes warm, 
 and on cooling deposits the compound in white shining scales, insoluble in water and 
 in ether, but easily soluble in alcohol. At 100 C. it decomposes after a while, giving 
 off sulphuretted hydrogen. Treated with hydrochloric acid, it yields chloride of 
 
 / /~1QJ\" TT f^STTll ) "M" 
 
 amylium, and amylsulphocarbamic acid \ HIS' wn ^ cn * s an ^7 k d y> 
 
 soluble in ether, ammonia and potash ; mixed with amylamine, it reproduces the 
 original salt. (A. W. Hofmann, Chem. Soc. Qu. v J. xiii. 60.) 
 
 DIAMYLAMINE, (C 5 !! 11 ) 2 !!^. When amylamine is heated to 100 C. with bromide 
 of amyl. direct combination occurs, and the solid hydrobromate of diamylamine is formed. 
 The base is obtained by distillation of the bromide with caustic potash (Hofmann, 
 Phil. Trans. 1851, p. 357). Slightly soluble in water. Boiling-point about 170. 
 The salts of diamylamine are difficultly soluble in cold water, more readily in hot 
 water. 
 
 TBIAMYLAMINE, (C 5 H M ) 3 N, is obtained by heating diamylamine with bromide of 
 amyl, and distilling the so-formed bromide of triamylium with caustic potash (Hof- 
 mann). Its properties and those of its salts are similar to those of diamylamine. It 
 boils at about 257 C. 
 
 TETKAMYLIUM, N(C 5 H n ) 4 . Tttr amyl ammonium. Ammonium in which the whole 
 of the hydrogen is replaced by amyl. Not known in the separate state, but obtained 
 as an iodide by the action of iodide of amyl on triamylamine, the mixture solidifying, 
 after three or four days' boiling, into an unctuous crystalline mass. The iodide of 
 tetramylium is also produced, but very slowly, by heating iodide of amyl in a sealed 
 tube with strong aqueous ammonia. This salt, N(C 5 H n ) 4 I, dissolves sparingly in 
 water, forming an extremely bitter liquid, from which it is precipitated in the crystal- 
 line form by alkalis. Boiled with oxide of silver, it yields a very bitter alkaline solu- 
 tion of the hydrate of tetramylium : 
 
 N(C"H)U + AgHO - Agl 
 
 On mixing the liquid with potash, or concentrating it strongly by evaporation, the 
 hydrate of tetramylium rises to the surface in the form of an oily layer, which 
 gradually solidifies. A moderately concentrated solution of the base left to evaporate 
 in an atmosphere free from carbonic acid, deposits the hydrate in definite crystals 
 sometimes an inch long, and containing several atoms of water of crystallisation. 
 These crystals when heated, melt in their water of crystallisation, and ultimately 
 leave the pure hydrate in the form of a semi-solid transparent mass. At higher 
 temperatures, the hydrate is completely decomposed, giving off water, triamylamine, 
 and a hydrocarbon, which is probably amylene : 
 
208 AMfLENE. 
 
 N(0H II ) 4 H.O = H 2 + N(C 5 H") 3 
 
 Hydrate of Triamy- Amylene. 
 
 tetramyliiun. lamine. 
 
 Hydrate of tetramylium dissolves readily in acids, forming solutions which yield 
 crystalline salts by evaporation. The sulphate crystallises in long, capillary threads : 
 the nitrate in needles, the oxalate in large deliquescent plates, the chloride in laminae 
 with palm-like ramifications; the chloroplatinate, (C 4 H l! ) 4 NCl.PtCl 2 , in beautiful 
 orange-yellow needles. (II of m an n, Chem. Soc. Qu. J. iv. 316.) F. GK 
 
 (For the Amyl-phosphincs, Ar sines, and Stibines, see PHOSPHORUS, ARSENIC, and 
 ANTIMONY.) 
 
 C 5 H 10 , or C } H. This hydrocarbon, a homologue of ethylene or 
 olefiant gas, and the fifth term of the series, OH 2n , is produced by the dehydration 
 of amylic alcohol by sulphuric acid, phosphoric anhydride, or chloride of zinc, also by 
 the dry distillation of amyl-sulphate of calcium (Kekule). To prepare it, a con- 
 centrated aqueous solution of chloride of zinc is heated to 130 C., with an equal volume 
 of amylic alcohol : and the product is distilled from a water-bath over caustic potash, 
 and repeatedly rectified (Balard, Ann. Ch. Phys. [3] xii. 320). It is a transparent 
 colourless, very thin liquid, having a faint but offensive odour. Boils at 39 C. 
 (Balard); at 35 (Frankland); at 42 (Kekule). Vapour-density, 2-68 (Balard), 
 2-386 (Frankland), 2-43 (Kekule); (by calculation, for 2 vol. = 2-4265). The 
 vapour is rapidly and completely absorbed by sulphuric anhydride and pentachloride 
 of antimony (Frankland). It possesses anaesthetic properties, and has been tried 
 as a substitute for chloroform, but has been found to be very dangerous, having in 
 more than one instance led to fatal results. 
 
 Amylene is diatomic, like ethylene, uniting with 2 at. Br, NO 2 , HO, &c., and with 
 1 at. O, S, &c. 
 
 ACETATE OF AMYLENE, C 9 H 16 4 = /V^TrsQ^ ( O 2 , is produced by heating the bro- 
 mide C'H^Br 2 , with a mixture of acetate of silver mixed with glacial acetic acid : 
 C 5 H 10 Br 2 + 2(C 2 H 3 O.Ag.O) = 2AgBr 
 
 It is a colourless neutral liquid, insoluble in water, boiling above 200 C and easily 
 decomposed by alkalis into acetic acid and amylene-glycol. (Wurtz, Ann. Ch. Phys. 
 [3] Iv. 458.) 
 
 BROMIDE OF AMYLENE, C 5 H 10 Br 2 , is produced by passing bromine-vapour into amy- 
 lene. Heated in a sealed tube with alcoholic ammonia, it forms bromide of ammo- 
 nium, and bromamylene, C 5 H 9 Br. By treating amylene with a larger quantity of 
 bromine, another compound is formed, containing C 5 H 9 Br 3 , probably dibromide of 
 bromamylene, C 5 H 9 Br.Br 2 . This compound, treated with alcoholic potash, yields di- 
 bromamylene, C 5 H 8 Br 2 . (C a hours, Ann. Ch. Phys. [3] xxxviii. 90.) 
 
 /Q5TT10N ) 
 
 HYDRATE OF AMYLENE, or AMYLENE-GLYCOL, C 5 H 12 2 == Jp \ 2 ' ?re P ared 
 by distilling acetate of amylene with dry pulverised hydrate of potassium, and purified 
 by a second distillation in the same manner, and subsequent rectification per se : 
 
 (OTTO)'! * + 2KH = 
 
 It is a colourless, very syrupy liquid, having a bitter taste with aromatic after-taste. 
 When cooled with a mixture of solid carbonic acid and ether, it solidifies into a hard 
 transparent mass. It does not affect polarised light. Its specific gravity is 0*987 at 
 C. It boils at 177, and distils without alteration. When pure it dissolves in water 
 in all proportions. The aqueous solution turns acid when exposed to the air in contact 
 with platinum-black, yielding chiefly carbonic acid, with only a small quantity of a 
 fixed acid, apparently butylactic acid. When gently heated with nitric acid, it is 
 rapidly oxidised, the chief product of the action being butylactic acid, C 4 H 8 3 . 
 (Wurtz, loc. cit.} 
 
 Amylene-glycol, treated with hydrochloric acid, either gaseous or aqueous, is con- 
 verted, slowly at ordinary, more quickly at higher temperatures, into the chlorhydrin 
 of amylene-glycol, C 5 H 10 .HO.C1. This compound cannot be isolated, but remains dis- 
 solved in the excess of acid and is decomposed by distillation. The acid solution 
 treated with potash yields oxide of amylene. 
 
 NITRYLIDE OF AMYLENE, C 5 H'(N0 2 ) 2 . Nitroxidc of Amylene. Obtained by 
 passing peroxide of nitrogen (nitryl, NO 2 , prepared by heating anhydrous nitrate of lead) 
 into a flask containing amylene, and surrounded by a freezing mixture. The gas is in- 
 
AMYLENE. 209 
 
 stantly absorbed, and the amylene is gradually converted into a pasty mass of minute 
 crystals, which may be purified by washing with cold alcohol, recrystallisation from 
 boiling ether and drying in vacuo over sulphuric acid. It gave by analysis, 3 7 '26 
 per cent. C, 6-51 H, and 17'66 N; the formula requiring 37'09 C, 618 H, and 17'28N. 
 
 The compound may also be obtained, though less advantageously, by passing vapour 
 of amylene mixed with air into fuming nitric acid. It is remarkable as affording the 
 first example of the direct combination of nitryl, (NO 2 ), with an organic radicle. 
 
 Heated by itself in a dry tube, it decomposes at about 95 C., giving off nitrous an- 
 hydride, N 2 O 3 , and nitrous acid, HNO 2 , and leaving a heavy liquid apparently containing 
 nitrate of amyl. Heated with quick lime, it gives off an aromatic body, probably con- 
 sisting of oxide of amylene. (Guthrie, Chem. Soc. Qu. J. xiii. 45, 129.) 
 
 OXIDE OF AMYLENE, (C 5 H 10 )".0, a volatile liqnid, isomeric with valeric aldehyde, 
 It boils at 95 C. Has a pleasant ethereal odour, and a rough taste. Specific gravity 
 in the liquid state, 0-8244 at C. Vapour-density by experiment 2'982, by calcula- 
 tion (2 vol.) = 2'805. It burns easily, with a yellow flame. It is insoluble in water, 
 and is not converted into amylene-glycol when heated with water in a sealed tube. 
 It dissolves in alcohol, in ether, and in a mixture of the two. It mixes with acids. It- 
 unites with anhydrous or crystallisable nitric acid at a higher temperature, but the 
 combination is attended with partial decomposition. (A. Bauer, Compt. rend. 
 li. 500.) 
 
 AMYLENE -WITH SULPHUR AND CHLORINE : 
 
 1. Dichlorosulphide of Amylene, C 5 H 10 SCP, or C l H"S 2 CP. Protochloride of sul- 
 phur (SCI 2 ) is brought into a flask surrounded with ice and an excess of amylene 
 added very gradually. The excess of amylene is evaporated off, the residue digested 
 and washed with water, dissolved in ether, filtered, and evaporated. It is a non- volatile 
 liquid, having a pungent odour, insoluble in water, soluble in ether and alcohol. 
 Specific gravity, 1*149 at 12 C. Distilled with excess of alcoholic caustic potash, it 
 yields amylene, disulphide of fusyl (C 5 H 9 S), and other products. 
 
 2. Disulphochloride of Amylene, C 5 H 10 SC1, or C 10 H lo &Cl.On treating disulphide 
 of chlorine (SCI), with excess of amylene, and evaporating the latter, a transparent 
 yellow, non- volatile liquid, of faint and nauseous odour is obtained, having the above 
 composition. It is obtained pure by digestion with water, solution in ether, filtration, 
 and evaporation. Specific gravity, 1-149 at 12 C. Soluble in ether, absolute alcohol, 
 and sulphide of carbon. (Guthrie, Chem. Soc. Qu. J. xii. 112.) 
 
 Disulphochloride of amylene treated with chlorine, giA r es off hydrochloric acid, and 
 is converted into a non-volatile liquid, of specific gravity 1-406 at 16 C., miscible with 
 ether, insoluble in water, but soluble in hot alcohol. This liquid gave by analysis 
 numbers agreeing approximately with the formula, CPWCPS, which may be that of 
 chlorosulphide of trichloramylene, C^IPCl^.SCl, or that of sulphide of tetrachloramyl, 
 C">(WCl*)S. (Guthrie, Chem. Soc. Qu. J. xiii. 43.) 
 
 AMYLENE WITH SULPHUR AND OXYGEN : 
 
 Disidphoocide of Amylene, WH^S^O. Prepared by digesting the disulphochloride in 
 alcoholic solution with protoxide of lead, till all the chlorine is combined, dissolving in 
 ether, filtering and evaporating. Specific gravity, 1-054 at 13 C. Non- volatile, yellow, 
 or almost colourless. Soluble in ether and alcohol, insoluble in water. 
 
 Hydrate of Disulphoxide of Amylene, C l H l S 2 O.HO. Disulphochloride of amylene is 
 heated in alcoholic solution for some hours, in a current of ammonia ; the liquid is then 
 poured off from the chloride of ammonium formed, and heated for some hours in a 
 sealed tube to 100 C. with alcoholic ammonia ; the excess of alcohol is driven off 
 in a water-bath ; the residue treated with water ; and the oil which is thereby pre- 
 cipitated is washed with water. Yellow liquid of meaty odour. Somewhat soluble 
 in hot water, soluble in alcohol and ether. Non-volatile. Specific gravity 1-049 at 
 8. (Guthrie, Chem. Soc. Qu J. x. 120.) F. G. and H. W. 
 
 ACID, C 44 H 64 7 . or C^H 32 O 7 . This acid is contained, together 
 with cardol, in the pericarps of the cashew nut (Anacardium occidentale). The pericarps 
 are extracted with ether, which dissolves out both the anacardic acid and the cardol ; 
 the ether is distilled off, and the residue, after being washed with water to free it from 
 tannin, is dissolved in 15 or 20 times its weight of alcohol. This alcoholic solution is 
 digested with recently precipitated oxide of lead, which removes the anacardic acid in 
 the form of an insoluble lead-salt. The lead-salt is suspended in water, and decom- 
 posed by sulphide of ammonium, and from the solution of anacardate of ammonium, 
 obtained after the removal of the sulphide of lead by filtration, the anacardic acid is 
 liberated by the addition of sulphuric acid. After repeated purification by solution in 
 alcohol, conversion into a lead-salt, and decomposition of this salt by hydrosul- 
 phuric acid, the acid is obtained as a white crystalline mass, which melts at 26 C. It 
 VOL. I. P 
 
210 ANACARDIC ACID ANALYSIS. 
 
 has no smell, but its flavour is aromatic and burning. When heated to 200 C. it is 
 decomposed, producing a colourless very fluid oil. It burns with a smoky flame, stains 
 paper, and liquefies by prolonged contact with air, emitting an odour similar to that 
 of rancid fat. Alcohol and ether dissolve it readily, and these solutions redden 
 litmus. 
 
 Some of its salts are crystalline, others amorphous. The silver-salt is a pulverulent 
 white precipitate, soluble in alcohol, in presence of a free acid. It contains two 
 atoms of metal, C 44 H B2 Ag 2 7 . The lead-salt, obtained by mixing a boiling alcoholic 
 solution of anacardic acid with an alcoholic solution of acetate of lead, is said to con- 
 tain C 44 H 60 Pb 4 7 or (7 44 # 30 P6 2 7 ; if this formula be correct, the acid is tetnibasic 
 [or dibasic, if the smaller atomic weights of carbon and oxygen are used]. The salts 
 of ammonium, potassium, barium, calcium and iron, have been described, but they are 
 not very definite, and their formulae have not been fixed. (Stadeler, Ann. Ch. 
 Pharm. Ixiii. 137.) 
 
 XL18TAX.CX1KE, siO 3 + H 2 = Na 2 O.Si0 2 + Al 4 3 .3Si0 2 + H 2 or 
 
 + 3(AP0 3 .2Si0 3 } + 2 HO. A. mineral belonging to the zeolite family 
 containing, according to H. Eose's analysis, 55'7 per cent, of silica, 13*5 soda, 23'0 
 alumina, and 8'3 water, which agrees very nearly with the preceding formula. It 
 belongs to the regular system. Primary form a cube ; it occurs also in leucite-octa- 
 hedrons, and in cubes with the faces of the leucite-octahedron replacing the solid 
 angles. Cleavage indistinct, parallel to the faces of the cube. Specific gravity from 2-1 
 to 2*2. Softer than felspar. In its purest form, it is colourless and transparent, but 
 sometimes white inclining to grey or flesh-colour. According to Brewster, it polarises 
 light in a peculiar manner, indicating a grouping of the molecules very different from 
 that which is usually found in the regular system. Before the blowpipe, it loses water 
 and becomes milk-white ; but when the heat is increased, it becomes clear again, and 
 then melts quickly to a transparent glass. It is readily decomposed by hydrochloric 
 acid, with separation of viscid silica ; after ignition, however, the decomposition is less 
 easy. Analcime occurs frequently in clefts and geodes in granite, trap-rocks and lava. 
 It is found on the Calton Hill, Edinburgh, at Talisker in the Isle of Sky, in Dumbarton- 
 shire, in theFerroe Islands, in the Harz, and in Bohemia. 
 
 ASLAX.YSZS 
 
 The object of chemical analysis is to ascertain the composition of any substance 
 whatever. The distinction usually made between organic and inorganic compounds, 
 has led to a corresponding division into organic and inorganic analysis : the latter 
 being confined to the investigation of inorganic or mineral compounds. The methods 
 employed in this branch of analysis, are far more numerous and varied than those 
 hitherto devised for the analysis of organic compounds. Inorganic analysis is divided 
 into qualitative and quantitative analysis. The former teaches us how to ascertain the 
 elements of a substance with regard to their quality only, and how to separate them one 
 from another: the latter establishes the methods of proceeding, by which we determine 
 the relations of weight or volume, which these elements bear to one another. It is 
 obvious that, before we can proceed to estimate the qiiantities of each element con- 
 tained in a compound, we must know what are the elements that it contains : hence 
 qualitative must always precede quantitative analysis. 
 
 Analysis is one of the most recent of the various branches of chemical science. Con- 
 siderable progress had already been made in synthetical chemistry, in the preparation 
 of chemical compounds, &c. at a time when the foundations of analytical chemistry 
 (in the sense at present attached to the term) had not even been laid. Less than a 
 century ago, when the properties and compounds of many elements were either entirely 
 unknown or but imperfectly established, few problems were more difficult than that of 
 inorganic analysis: the analyst had need of both penetration and caution in the highest 
 degree, in order to discriminate between known and unknown substances. It is only 
 within a comparatively recent period, that the discovery of many new elements, and 
 the more complete investigation of the reactions of those already known, have enabled 
 us to construct a systematic course of analysis, circumscribed within definite and well 
 established rules. 
 
 Analytical chemistry, as we have already observed, aims at two objects, each closely 
 connected with the other : 1. To ascertain what are the elements contained in sub- 
 stances whose composition is unknown : 2. To determine the relative proportions of 
 those elements whose existence has previously been qualitatively ascertained. In the 
 earliest analytical researches, both these objects were pursued simultaneously. Hence, 
 in the very brief sketch of the history of analytical chemistry, which it is now our 
 purpose to give, it is not possible to trace the progress of each of these branches of 
 analysis independently of the other. For this purpose it is more convenient to adopt 
 
ANALYSIS INORGANIC. 211 
 
 the distinction of analysis in the wet and in the dry way (vide infra) : for these two 
 branches of analysis aimed originally at different objects, and the progress of each 
 was in great measure independent of that of the other. 
 
 The earliest analytical methods of which we have any information were in the dry 
 way. They were directed exclusively to the separation of noble from ignoble metals ; 
 and they were generally conducted quantitatively, the object being to determine the 
 commercial value of alloys, &c., by extracting the amount of the most precious metal 
 contained in them. As early as the second century B.C., Agatharchides of Cnidos (quoted 
 by Diodorus Siculus) gives an account of a method employed by the Egyptians for the 
 extraction and purification of gold, which closely resembles the process of cupellation, 
 at present so extensively employed for the separation of silver from lead. Strabo 
 (about the Christian era) describes the extraction of silver from its ores by fusion with 
 lead ; and all the analytical methods which we meet with in the course of several 
 successive centuries are but modifications of the same process. We find a description 
 of the process given by Geber in the latter half of the eighth century, which corre- 
 sponds very closely with that at present employed. 
 
 Strictly speaking, the employment of analysis in the dry way for qualitative pur- 
 poses, is of much later date, commencing from the observation of the behaviour of 
 different metallic compounds when exposed to a high temperature in contact with 
 certain reagents, commonly called fluxes. It is to Pott, Professor of Chemistry at 
 Berlin, circ. 1750, that we owe the first distinct record of these observations; he 
 pointed out that it was possible, by the addition of certain fluxes, to fuse many 
 substances which were infusible alone ; and that the colour of the fused mass afforded 
 information as to the nature of the original substance. This method of experimenting, 
 which was conducted by him in crucibles and furnaces, on a comparatively large 
 scale, received an immense extension by the introduction of the blowpipe, by means 
 of which far more accurate indications were obtained with a much smaller quantity of 
 the original substance. The first mention of this implement occurs about 1660, in the 
 Memoirs of the Academia del Cimento, at Florence, when it is noticed as being em- 
 ployed by glass-blowers ; and the first indication of its use for chemical purposes, is 
 found in Kunkel's Ars vitraria experimentalis, 1679. Cramer, a German chemist, in 
 his Etementa Artis docimastica (1739), gives the earliest instructions for its "use as 
 an implement of analysis. The further investigation of the results to be attained by 
 means of this invaluable instrument, was effected mainly by a succession of Swedish 
 chemists, of whom Cronstedt and Bergman were perhaps the most remarkable ; and it is 
 to Berzelius that the establishment of the existing system of blowpipe analysis was 
 finally owing. 
 
 According to the present course of analysis, the method by the dry way is usually 
 employed only in the preliminary examination : the cases are very rare in which its 
 results can be relied upon for complete information as to all the constituents of a 
 substance. For this purpose, recourse is now invariably had to analysis in the wet way. 
 The early history of this method of analysis is very obscure, amounting in fact to 
 nothing but the enumeration of a few random reactions, in the employment of which 
 no system was observed. It was originally employed solely for the qualitative detection 
 of adulterations in drugs, &c. It was next directed to the examination of mineral 
 waters, to which purpose it was mainly confined until the latter half of the seventeenth 
 century, at which period the first true perception of the problem involved in analytical 
 chemistry was obtained by Boyle, who gave to this branch of the science the name by 
 which it is at present designated. He was the first to establish clearly the idea of a 
 chemical element, and to seek for methods of ascertaining what elements or known 
 compounds are contained in any substance of unknown composition. Although these 
 methods comprise many reactions which were known before his time, still he has the 
 credit of being the first to generalise these scattered facts, and to collect them into a 
 coherent system. Among the new reactions introduced in his time, we may mention 
 the precipitation of calcium-salts by sulphuric acid, as serving for the detection of 
 either calcium or sulphuric acid ; of silver-salts by hydrochloric acid, as a test for 
 both silver and chorine ; that of iron with tincture of galls ; the blue colour of copper- 
 salts with excess of ammonia, &c. Since the time of Boyle, analytical chemistry, in 
 the hands of Marggraf, Scheele, Bergman, Klaproth, H. Kose, &c. has made continual 
 advances, the enumeration of which cannot be attempted in a brief historical summary 
 like the present ; until by degrees it has assumed the systematic form of which wo 
 shall presently proceed to give an outline. 
 
 The establishment of quantitative analysis, as a distinct branch of chemical science, 
 is of comparatively recent date. For a long time it was almost entirely neglected, 
 little if any importance being attached to the relative proportions in which elements 
 exist in a compound. Until the latter half of the last century, it was confined to the 
 purpose of assaying, or of determining approximately the value of ores ; and it was not 
 
 p 2 
 
2 1 2 ANAL YSIS INORGANIC. 
 
 until Lavoisier, with such triumphant success, employed the balance as a means of 
 refuting old errors and of establishing new truths, that inquiries into the quantitative 
 composition of bodies came to be regarded as the only sure test and foundation for 
 chemical theory. Almost all the quantitative analyses by which any reliable know- 
 ledge of the constitution of substances has been obtained, are included in this period, 
 and date within the last 60 or 70 years. The empirical results thus obtained, have 
 led to the discovery of the most important theoretical truths, e.g. the theory of atoms 
 and equivalents, the law of multiple proportions, &c., which in turn have been of in- 
 estimable value in controlling the results of analysis, and ensuring to them a degree of 
 accuracy which could never have been attained by merely empirical determinations. 
 
 Until a comparatively recent period, the only method of quantitative analysis was 
 that by weight. By this method, the substance to be estimated is either weighed 
 directly, or in the form of some compound of known composition, from whose weight 
 that of the substance to be estimated is readily calculated, the reagent by which the 
 substance is separated being always employed in excess. More recently, another method 
 has been introduced, which depends upon the employment of only the exact quantity 
 of the reagent which is necessary to produce the reaction desired ; and upon the de- 
 termination of this quantity, not by weight, but by measure. This method, known as 
 the Volumetric method of analysis (see ANALYSIS VOLUMETRIC), is only applicable 
 in cases where the point at which the reaction is complete can be determined accu- 
 rately by means of some distinctly visible phenomenon occurring in the solution to be 
 analysed. The first introduction of this method is due to Descroizilles, who, at. the 
 close of the last century, applied it to the valuation of bleaching powder by means of 
 indigo-solution : since which time it has been gradually extended until it has grown 
 into a distinct and most important branch of analysis, which, in most cases, is at least 
 equal in accuracy to the method by weight, while it is greatly superior in speed and 
 facility of execution. 
 
 The methods of qualitative analysis consist in bringing the substance under ex- 
 amination into contact with other bodies of known properties, and observing the 
 phenomena which ensue. These phenomena consist in alterations, either in state of 
 aggregation, form, or colour, depending upon some chemical change. All bodies which 
 we employ for this purpose, we call by the general name of reagents, the ensuing phe- 
 nomena are called reactions. Acids, bases, salts, and simple bodies (elements) are 
 alike used as reagents. 
 
 By means of reagents, the chemist puts questions to the substance under examina- 
 tion, enquiring whether it contains this or that group of chemically similar elements, 
 or only this or that member of such group. If the question be put correctly i.e. if 
 all the conditions under which the reaction expected can be produced by the reagent 
 employed be carefully observed, the answer is decisive as to the presence or absence of 
 the element, or group of elements, sought : if, on the other hand, these conditions 
 i. e. the properties and chemical relations of the bodies formed by the chemical changes 
 which constitute the reaction, have been wholly or partially neglected, the answer, if 
 not certainly erroneous, is at least of doubtful accuracy. 
 
 Reagents may be employed either in the wet way or in the dry way. In the wet way, 
 the reagent in solution, i.e. in the liquid form, is brought into contact with the sub- 
 stance to be examined, which is also in the liquid form. In the dry way, the two 
 bodies are brought together in the solid state, and subjected to a high temperature. 
 Of the utmost importance in analysis by the latter method, is the knowledge of the 
 use of the blowpipe, and of the behaviour of bodies in the different flames which can 
 be produced by it. (See BLOWPIPE.) 
 
 Many reagents exhibit the same, or a similar behaviour, with a certain fixed number, 
 i. e. with a group, of elements, and with most of the compounds of these elements ; and 
 can therefore, be employed for the division of the elements into groups. Such reagents 
 are termed general reagents. Others serve for the further distinction of the several 
 members of such groups : their selection depends upon the knowledge of the special 
 characteristic behaviour to such reagents of each single element, or of each of its 
 several compounds. Such reagents are called special or characteristic reagents. Their 
 number is much greater than that of the general reagents, their nature being as various 
 as that of the substances which can come under examination : their selection depends 
 upon the solubility or insolubility, colour, or other physical or chemical properties of 
 the new compounds to which they give rise. They may frequently be employed re- 
 ciprocally : thus, starch is a characteristic test for iodine, and reciprocally, iodine is a 
 characteristic test for starch. 
 
 The analyst has not only to establish that this or that body is present in a compound, 
 but he has also to prove that no other body is present besides those which he has 
 actually found. Hence it is evident that he must not treat the substance under ex- 
 amination with any reagent indiscriminately. He must follow a certain fixed order, 
 
ANALYSIS INORGANIC. 213 
 
 a methodical system, in the application of reagents, which will be the jsame for all 
 inorganic sxibstances whatever, let their elements be what they may. This systematic 
 method, which cannot be departed from or abbreviated without danger, except in 
 certain cases by the experienced chemist, consists in the employment of general reagents 
 for the successive elimination of groups of elements possessing certain common chemical 
 properties ; and finally, in the recognition of each member of such groups by the em- 
 ployment of characterisric reagents. If the object be not a complete and accurate 
 analysis, but merely to establish the presence or absence of some particular body, the 
 characteristic reagent may in many cases be employed at once, without previous 
 recourse to general reagents. 
 
 The first thing to be done in the qualitative analysis of a solid body, is to subject 
 it to a preliminary examination in the dry way, by which means important information 
 as to its composition may frequently be obtained: after which it is dissolved, and its 
 constituents ascertained by examination in the wet way. The course of qualitative 
 analysis, therefore, consists of 3 parts : 
 
 I. Preliminary examination in the dry way. 
 II. Solution, or conversion into the liquid form. 
 III. Analysis of the solution in the wet way. 
 
 We shall now proceed to treat successively of each of these operations. 
 
 I. Preliminary Examination. 
 
 This consists partly in an accurate observation of the physical properties of the 
 substance (its form, colour, hardness, specific gravity, &c.) : but chiefly in observing 
 its behaviour at a high temperature, either alone, in contact with air, or with some 
 chemical compound which produces either decomposition or simple solution. 
 
 1. The substance is heated alone in a dry test-tube, on charcoal, or on platinum-foil. 
 Water, sulphur and its acids, ammonium-, arsenic-, and mercury-compounds are 
 completely volatilised. Carbon burns when heated in the air. If water is evolved, 
 observe whether it is acid or alkaline to litmus. If gases are evolved, observe whether 
 they are combustible : and if so, whether their combustion is sustained or intermittent. 
 Organic compounds are decomposed by heat, generally with evolution of inflammable 
 gas and separation of carbon : when heated with strong sulphuric acid and bichromate 
 of potassium, they evolve carbonic anhydride, which gives a white precipitate with 
 lime- or baryta-water. Bodies which are very rich in oxygen, nitrates, chlorates, per- 
 chlorates, bromates, iodates, deflagrate when heated on charcoal. Most alkaline, and 
 some alkaline-earthy salts, melt without volatilising or changing colour ; after strong 
 ignition, the residue is alkaline to test-paper. Many silicates (especially zeolites) 
 melt when a thin fragment of them is exposed in platinum-tongs to the blowpipe flame. 
 Borates and alum swell up : other salts, e. g. chloride of sodium, decrepitate. Of 
 metals: antimony, lead, tin, bismuth, cadmium, zinc, tellurium, fuse readily before 
 the blowpipe, giving an incrustation of oxide; gold, silver, and copper, fuse with 
 difficulty, and give no incrustation; iron, nickel, cobalt, molybdenum, wolfram, and 
 platinum metals are infusible. The oxides and salts of the earthy and alkaline-earthy 
 metals are infusible, or difficultly fusible ; they become vividly incandescent, with a 
 white light, but do not change colour ; the earths, after ignition, are not alkaline to 
 test-paper. The oxides and salts of some metals assume a darker colour when heated : 
 those of zinc, tin, titanium, columbium (niobium), and antimony, become yellow : those 
 of lead, bismuth, mercury (and chromates), become dark-brown. 
 
 2. The substance, after ignition on charcoal, is moistened with a drop of a solution 
 of nitrate of cobalt, and again strongly heated before the blowpipe. Alkaline phosphates 
 borates, and silicates, give a blue glass : the earths, earthy phosphates, silica and many 
 silicates give a blue infusible mass : zinc-oxide and titanic anhydride become yellowish- 
 green : binoxide of tin, bluish-green : antimonic and columbic anhydrides, dirty-green : 
 magnesia and tantalic anhydrides, flesh-red : baryta, brown or brick-red : glucina, 
 lime, and strontia, grey. 
 
 3. The substance is heated on platinum-wire (if a metallic salt, on charcoal) in the 
 inner blowpipe flame, and the colour of the outer flame observed. A yellow colour in- 
 dicates sodium : a violet, potassium : a carmine-red, lithium or strontium. The yellow 
 colour imparted by sodium, completely overpowers those of the other alkaline metals : 
 but, if the flame be observed through dark blue glass, the yellow rays are cut off, and 
 the colours of potassium and lithium are plainly visible, even in presence of a'large 
 excess of sodium. A reddish-yellow colour indicates calcium ; a yellow-green, barium or 
 molybdenum ; a green, cupric oxide, phosphoric, boric, or tellurous acid ; a blue, arsenic, 
 antimony, lead, selenium, or cupric chloride. In many cases, the colour is rendered 
 more apparent if the substance be previously moistened with hydrochloric acid, or a 
 
 p 3 
 
1214 ANALYSIS INORGANIC. 
 
 little chloride of silver added: phosphates and borates should be moistened with 
 sulphuric acid. 
 
 The delicacy and sharpness of these chromatic indications are greatly increased by 
 a method of observation lately introduced by Bunsen and Kirchhoff. It consists 
 mainly in igniting a metallic salt on platinum wire, in a feebly luminous and nearly 
 monochromatic flame, such as that of a Bunsen's gas-burner, and observing the 
 flame through a prism. Very characteristic spectra are then produced, containing 
 luminous coloured bands coincident in position with certain of Fraunhofer's lines. 
 Sodium gives a spectrum reduced to a single bright narrow band; lithium, a bright 
 red and a fainter yellow band ; potassium, a spectrum nearly resembling the ordinary 
 solar spectrum in the middle, but characterised by a bright line near the red ex- 
 tremity, and a fainter line near the violet end of the spectrum. The strontium 
 spectrum consists of a broad bright orange band, with some fainter red bands ; the 
 calcium spectrum, of a broad bright green band, a somewhat narrower bright orange 
 band, and some fainter yellow bands; and that of barium, of several bright green, 
 yellow and orange with two faint red bands. The sodium reaction is extremely 
 delicate, sufficing for the detection of a quantity of sodium as small as 3^5000 f 
 a milligramme ; distinct indications are likewise obtained with 1000 9 OQO(5 of a milli- 
 gramme of lithium, T ^ milligramme of potassium and barium, 1 . Q( f 000 milligramme 
 of strontium, 1000 6 0000 milligramme of calcium. (For details see the article LIGHT ; also 
 Pogg. Ann. ex. 161 ; Chem. Soc. Qu. J. xiii. 270.) 
 
 4. The substance is heated on charcoal in the, reducing flame with carbonate of 
 sodium, or with carbonate of sodium and cyanide of potassium. Most arsenic com- 
 pounds give a smell of garlic. All sulphur-, selenium-, and tellurium-compounds, give 
 an alkaline sulphide, selenide, or telluride, which, when moistened, leaves a black 
 stain on a clean silver plate. Tin-, silver-, copper-, and gold-compounds give malleable 
 shining scales : compounds of nickel, cobalt, iron, molybdenum, wolfram, and the 
 platinum-metals are reduced to a grey infusible powder : no incrustation is formed in 
 any of these cases. Antimony-compounds give a brittle metallic globule, and a white 
 incrustation : bismuth, a brittle globule and a brown-yellow incrustation : lead, a 
 malleable globule, and a yellow incrustation. Zinc and cadmium are not reduced to 
 the metallic state, but give, the former a white incrustation, not volatile in the outer 
 flame, the latter, a brown-red incrustation. 
 
 5. The substance is heated in a glass tube, open at both ends, held obliquely. The 
 following substances yield gases having a peculiar smell : sulphides, of burning sulphur ; 
 selenides, of horseradish; arsenides, of garlic; many ammonium-salts, of ammonia; 
 fluorides (especially on addition of microcosmic salt), of hydrofluoric acid. A metallic 
 sublimate indicates arsenic- or mercury-compounds : a white sublimate is given by 
 arsenides (crystalline), by antimonides and tellurides, (fusible), and by many ammonium- 
 salts. A fused sublimate is given by the higher sulphides (brown-yellow), by selenides 
 and selenium (blackish-red), and by sulphide of arsenic (yellow). All hydrated salts 
 or substances containing hygroscopic water yield drops of water, the acid or alkaline 
 reaction of which should be ascertained. 
 
 6. The substance is heated in contact with metallic zinc and dilute hydrochloric or 
 sulphuric acid. Many metallic acids are reduced to lower oxides by this treatment, 
 a change of colour being produced. Titanic acid gives a violet colour : tungstic acid, 
 and the chlorides of tantalum and columbium, a blue : molybdic acid, blue, changing to 
 green and dark-brown : columbous acid, blue, changing to dark brown ; chromic acid, 
 green, iodic acid, brown, or if starch be added, blue. 
 
 II. Solution of Solid Bodies. 
 
 After having ascertained by the preliminary examination in the dry way, to what 
 class of bodies the substance under examination belongs, the next step is to bring it 
 into the liquid form, in other words, to dissolve it. In order to effect this, it is generally 
 necessary, when the nature of the substance allows it, to reduce it to a fine powder by 
 pounding in a mortar, and, if necessary, by subsequent levigation with water. This 
 is indispensable in the case of minerals, especially of silicates, and of all other difficultly 
 soluble, insoluble, or difficultly decomposible compounds. If the substance contains 
 organic matter, this should be removed before proceeding further, as its presence 
 materially interferes with the reactions of many mineral compounds. This may gene- 
 rally be effected by heating the substance strongly for some time in contact with air 
 (more speedily with oxygen), until the whole of the carbon is converted into carbonic 
 anhydride. In many cases, the oxidation of the carbon is facilitated by dropping nitric 
 acid on the heated substance. 
 
 The solvents which are usually employed in the analysis of inorganic bodies are 
 water, hydrochloric and nitric acids, and aqua-regia. The finely-powdered substance 
 is first boiled with from 12 to 20 time'* its weight of distilled water, in order to ascertain 
 
ANALYSIS INORGANIC. 215 
 
 its complete or partial solubility or insolubility therein. If it be not completely dis- 
 solved, the solution is filtered off from the residue, and a drop or two of it evaporated 
 to dryness on platinum-foil, when, if the substance is partially soluble in water, a dis- 
 tinct residue is left ; if the substance is completely insoluble, there is no residue after 
 evaporation. In the former case, the solution is tested with litmus paper to see whether 
 it has a neutral, acid, or alkaline reaction, and set aside for further examination. 
 The portion insoluble in water is then treated successively with dilute and concentrated 
 hydrochloric acid, particular attention being paid to the nature of the gases, if any, 
 thereby evolved, and to the separation of solid products of decomposition. Carbonates 
 evolve carbonic anhydride, with effervescence ; peroxides, chromates, and chlorates 
 evolve chlorine; cyanides, hydrocyanic acid; many sulphides, hydrosulphuric acid; 
 sulphites and hyposulphites, sulphurous anhydride, with separation of sulphur in the 
 latter case. Most metals (iron, zinc, tin, &c.) evolve hydrogen ; or, if arsenic or an- 
 timony be present, arsenide or antimonide of hydrogen. If hydrochloric acid does not 
 completely dissolve the substance, it generally effects the complete separation of one 
 or more elements ; for which reason the solution should be separated from the residue, 
 and examined apart. The residue may consist of compounds undecomposible by 
 hydrochloric acid, which existed in the original substance ; or of insoluble compounds 
 formed by the decomposition of the original substance by hydrochloric acid. Thus 
 sulphur is separated from polysulphides, pulverulent or gelatinous silica from many 
 silicates, tungstic acid from tungstates, &c. ; or if lead, silver, or subsalts of mercury 
 be present, insoluble chlorides of these metals will be formed. 
 
 If the substance is not completely soluble in hydrochloric acid, the insoluble residue 
 is treated successively with nitric acid and aqua regia. In many cases (e. g. with 
 phosphates, arsenates, silicates, tungstates, &c.), these compounds act merely as solvents; 
 on many other bodies they exert an oxidising action. Thus, most sulphides, when 
 treated with nitric acid, separate sulphur, which, by prolonged digestion with the acid, 
 collects into yellow globules which swim on the surface of the liquid, or disappears 
 altogether, being oxidised into sulphuric acid, which may be detected in the solution, 
 unless it forms an insoluble salt with the dissolved metal. Sulphide of lead is con- 
 verted by nitric acid into sulphate of lead : sulphides of antimony and tin into white 
 oxides: protosulphide of mercury is insoluble in nitric acid, readily soluble in aqua regia. 
 Most metals are completely soluble in nitric acid : the only metals not attacked by it 
 are gold, platinum, and the rarer metals found in platinum-ores (with the exception 
 of palladium, which is slowly soluble in nitric acid). Gold and platinum are soluble 
 in aqua regia. Tin and antimony are not dissolved by nitric acid, but are converted 
 into white oxides, insoluble in the acid ; they are readily soluble in aqua regia (or 
 hydrochloric acid and chlorate of potassium), if excess of nitric acid be avoided. 
 
 When a finely powdered substance is neither dissolved by successive treatment with 
 the above solvents, nor so decomposed or attacked by them as to give an idea of its 
 nature, it must be rendered soluble, in order that its constituents may be determined 
 in the wet way. The method of doing this frequently depends upon the results of 
 the preliminary examination. The following are the principal insoluble (or difficultly 
 soluble) substances. 
 
 1. Sulphates (of barium, strontium, calcium, and lead). When heated on charcoal 
 with carbonate of sodium, they give an alkaline sulphide : sulphate of lead gives also 
 a malleable metallic globule ; it is blackened by sulphide of ammonium, and soluble 
 in basic tartrate of ammonium. They are rendered soluble by fusion with 3 4 pts. 
 alkaline carbonate : after treating the fused mass with water, the solution contains 
 the acid as alkaline sulphate, and the residue the base, as carbonate, which is now 
 soluble in hydrochloric acid. In this and in all the following cases, the substance 
 must be powdered as finely as possible before fusion. The sulphates of strontium, 
 calcium, and lead are decomposed (the first not completely), by digestion with a solu- 
 tion of sodic carbonate : sulphate of calcium is somewhat soluble in water. 
 
 2. Silica and silicates. When heated before the blowpipe with microcosmic salt, 
 they swim undissolved in the fused bead. They are rendered soluble by fusion with 
 3 4 pts. alkaline carbonate (or hydrate of barium), treatment with hydrochloric acid, 
 and evaporation with free acid, when the silica remains insoluble ; or by treatment 
 with hydrofluoric and sulphuric acids. 
 
 3. Fluorides (fluorspar, &c.) When gently heated with concentrated sulphuric 
 acid, they evolve hydrofluoric acid, which corrodes glass : if silica be present, fluoride 
 of silicium is evolved, which gives a precipitate on contact with water. They are 
 decomposed by fusion with 4 pts. alkaline carbonate, with addition of silica if neces- 
 sary. 
 
 4. Alumina or Aluminates.Tkey give a blue infusible mass when heated with 
 cobalt-solution. They are rendered soluble by fusion with 34 pts. acid sulphate of 
 potassium. 
 
 p 4 
 
216 ANALYSIS- QUALITATIVE. 
 
 5. Chromic oxide (chrome-iron-ore). It gives a green bead in both flames with 
 borax or microcosrnic salt. Chrome-iron-ore is decomposed by successive fusion with 
 acid sulphate of potassium, and with alkaline carbonate and nitre. 
 
 6. Binoxide of tin, and Antimonic anhydride. They are coloured yellow by sul- 
 phide of ammonium, and dissolved by digestion in excess of the reagent : when heated 
 on charcoal with sodic carbonate, they yield, the first a malleable, the second a brittle, 
 metallic globule. They are rendered soluble in acids by fusion with 3 4 pts. alkaline 
 carbonate. 
 
 7. Tantalic, tungstic, titanic, and columbous anhydrides. They give with micro- 
 cosmic salt a blue, violet, or (in presence of iron) a blood-red, bead : with zinc and 
 hydrochloric acid, a coloured solution. They are rendered soluble by fusion with 6 pts. 
 acid sulphate of potassium. 
 
 8. Chloride \ bromide, iodide, of silver ; Sulphides of molybdenum, lead, cfc. Chloride, 
 bromide, and iodide of silver, are soluble in cyanide of potassium : when heated on char- 
 coal with sodic carbonate, they yield metallic silver. Insoluble sulphides give off 
 sulphurous anhydride when heated : sulphide of molybdenum gives a yellowish-green 
 bead with microsmic salt, and is converted by roasting into niolybdic anhydride, which 
 gives a blue colour with zinc and hydrochloric acid. 
 
 9. Metals (osmide of iridium, or residues of platinum-ores). The insoluble sub- 
 stance has metallic lustre, or is a black powder, not affected by ignition. It is rendered 
 soluble by mixture with chloride of calcium and ignition in a stream of chlorine ; or 
 by fusion with potash and chlorate of potassium. 
 
 10. Carbon. The insoluble substance is black (as diamond, colourless) : it dis- 
 appears when strongly ignited in an open platinum crucible, or before the blowpipe. 
 It detonates when fused with nitre, forming carbonate of potassium ; and yields 
 carbonic anhydride when ignited with oxide of copper. 
 
 If the preliminary examination furnishes no distinct idea as to the nature of the 
 insoluble substance, it must be fused with four times its weight of carbonates of potas- 
 sium and sodium, the fused mass exhausted with water, and the residue treated with 
 hydrochloric acid. If the substance contains any easily reducible metal (arsenic, 
 antimony, tin, lead, bismuth, &.) it must not be fused in a platinum crucible. 
 
 III. Qualitative Analysis of Solutions. 
 
 The first steps to be taken in the qualitative analysis of solutions are to ascertain 
 whether the solution is neutral, aeid, or alkaline to test paper ; and whether it contains 
 any non- volatile constituents. For the latter purpose, a small portion of it is care- 
 fully evaporated on platinum-foil: when, if non-volatile compounds are present, a 
 residue is left which does not disappear when strongly heated, and should be submitted 
 to the preliminary examination above described. 
 
 These precautions are of course unnecessary when the solution has been made by 
 the analyst himself, as described in Section II. : but they should never be neglected 
 when the substance to be examined is already in the liquid form, since, if carefully 
 performed, they may enable him to conclude at once as to the presence or absence of 
 whole groups of bodies. Thus it is evident that a solution which, after careful evapo- 
 ration, leaves no fixed residue, cannot contain any non-volatile metallic salts. A 
 solution neutral to test-paper can generally contain only salts of the alkaline or alkaline- 
 earthy metals, since the salts of most other metals have an acid reaction. An alkaline 
 solution (in which no non-volatile organic compounds are present), cannot contain any 
 metals whose salts are insoluble in alkaline liquids : if the alkaline reaction be caused 
 by the presence of an alkaline carbonate, the presence of the alkaline-earthy metals 
 is impossible. If, however, non-volatile organic compounds are present, an alkaline 
 solution may contain salts of copper or sesquisalts of iron, as well as such oxides, 
 cyanides, sulphides, &c., as are soluble in cyanide of potassium or alkaline sulphides. 
 The presence of certain acids implies the absence of certain metals, and vice versa : 
 thus the same acid solution cannot contain sulphuric acid .and barium, hydrochloric 
 acid and silver, &c. Silver need not be looked for in an alloy soluble in hydrochloric 
 acid, nor gold, antimony, tin, &c. in one soluble in nitric acid. 
 
 It is advisable, when possible, to examine for acids and metals in separate portions 
 of the solution. 
 
 a. Examination for Metals. 
 
 The systematic course of examination for metals which is now almost exclusively 
 employed, depends upon the behaviour of metallic salts in solution towards the follow- 
 ing general reagents : hydrochloric acid, hydrosulphuric acid, sulphide of ammonium, 
 and carbonate of ammonium. It will be observed that all these reagents are volatile ; 
 so that in their application no substance is introduced into a solution which cannot 
 
ANALYSIS INORGANIC. 217 
 
 be removed by simple elevation of temperature. Their application depends upon 
 the different solubility of metallic chlorides and sulphides, and of the carbonates of 
 the alkaline-earthy and alkaline metals. By means of these general reagents, as 
 we have already observed, the metals are divided into certain groups, which are 
 successively eliminated from the solution under examination; by which proceeding 
 the detection of each individual member of each group is considerably facilitated. 
 The following are the groups into which the metallic elements are thus divided : 
 
 o. Metals whose chlorides are insoluble, or difficultly soluble in water or dilute acids. 
 These are lead, silver, and mercury (the last as sub-salts). These metals are not gene- 
 rally classed in a group by themselves, but are included in the group next following, 
 to which they also belong." 
 
 6. Group 1. Metals whose sulphides are insoluble in water or in dilute acids. 
 They are all precipitated from their slightly acid solution by hydrosulphuric 
 acid. They are further divided into two subdivisions according to the behaviour of 
 their sulphides to sulphide of ammonium. 
 
 Subdivision A. Metals whose sulphides possess acid properties. Their sulphides 
 are soluble in alkaline sulphides (sulphides of ammonium, potassium, or sodium), 
 forming therewith soluble sulpho-salts, which are generally analogous to the oxygen 
 salts of the same metals, oxygen being replaced by sulphur. They are arsenic, anti- 
 mony, tin, gold, platinum, iridium, selenium, tellurium, molybdenum, wolfram, 
 vanadium. 
 
 Subdivision B. Metals whose sulphides do not possess acid properties, not com- 
 bining with alkaline sulphides, and so being insoluble therein. They are lead, silver, 
 mercury, bismuth, copper, cadmium, palladium, rhodium, osmium, ruthenium. (Sul- 
 phide of mercury is soluble in sulphide of potassium or sodium : sulphide of copper is 
 somewhat soluble in sulphide of ammonium.) 
 
 7. Group 2. Metals which are not precipitated by hydrosulphuric acid, but which 
 are precipitated by sulphide of ammonium, from acid solutions. This group 
 also is further subdivided. 
 
 Subdivision A. Metals which are precipitated as sulphides. They are nickel, 
 cobalt, manganese, iron, uranium, zinc. Their sulphides are insoluble in water, but 
 soluble in dilute acids, with evolution of hydrosulphuric acid: hence they are not 
 precipitated at all by hydrosulphuric acid from acid solutions, and not completely 
 from neutral solutions. They are however completely precipitated from an acid solu- 
 tion by sulphide of ammonium, the acid being neutralised by the ammonia contained 
 in it. 
 
 Subdivision B. Metals which are precipitated as hydrates. They are aluminium, 
 glucinum or beryllium, zirconium, thorium, yttrium, erbium, terbium, cerium, lan- 
 thanum, didymium : titanium, tantalum, columbium, chromium. (The first ten metals 
 in this subdivision are known as metals of the earths, or earthy metals'}. They do not 
 combine with sulphur in the wet way, and so are not precipitated by hydrosulphuric 
 acid under any circumstances. Their hydrates, however, being insoluble in water, are 
 precipitated from their neutral or acid solutions by sulphide of ammonium, the acid 
 by which they were held in solution being neutralised by the ammonia of the reagent, 
 while hydrosulphuric acid escapes. 
 
 Certain compounds of the earthy and alkaline-earthy metals with non-volatile acids 
 (phosphates, oxalates, borates, &c.), being soluble in dilute acids and insoluble in 
 water, are similarly precipitated by sulphide of ammonium. 
 
 5. Group 3. Metals whose sulphides and hydrates are soluble in water ; which, 
 therefore, are not precipitated by hydrosulpuhric acid or sulphide of ammonium from 
 any solution. This group includes the alkaline-earthy and alkaline metals. They are 
 further subdivided according to their behaviour to carbonate of ammonium in presence 
 of chloride of ammonium. 
 
 Subdivision A. Metals which are precipitated by carbonate of ammonium. 
 They are barium, strontium, calcium. Their normal carbonates are insoluble in water 
 or in chloride of ammonium. 
 
 Subdivision B. Metals which are not precipitated by carbonate of ammonium. 
 They are magnesium, potassium, sodium, lithium, ammonium. Carbonate of magne- 
 sium is insoluble in water, soluble in chloride of ammonium : the carbonates of the other 
 four metals (alkaline metals), are soluble in water. The different solubility of their 
 phosphates affords a means for the further detection of the metals of this subdivision. 
 
 In the usual classification, the alkaline-earthy metals (barium, strontium, calcium, 
 magnesium) constitute Group 3 : and Group 4 comprises the alkaline metals. 
 
 The following table exhibits in a compendious form the behaviour of all the 
 metals to the general reagents above enumerated. 
 
218 
 
 ANALYSIS INORGANIC. 
 
 Behaviour of Metallic Solutions with Hydrochloric Acid, 
 
 Ammonium, 
 
 Hydrochloric 
 Acid. 
 
 Hydrosulplmric Acid. 
 
 
 Metals which are pre- 
 
 i 
 
 Metals which are precipitated as sulphides from their 
 
 A 
 Metals whose salts 
 
 
 cipitated as chlorides 
 
 hydrochloric acid solution by hydrosulphuric acid. 
 
 are partly re- 
 
 
 from their neutral or 
 
 
 duced in an acid 
 
 
 acid solutions by hy- 
 
 
 solution by hy- 
 
 
 drochloric acid.* 
 
 
 drosulph. acid, 
 
 
 
 
 with separation 
 
 
 
 
 of sulphur.* 
 
 
 Lead (partially), white, 
 
 Soluble in sulphide of 
 
 \ 
 
 Insoluble in sulphide 
 
 Iron as ferric 
 
 
 crystalline, soluble in 
 
 ammonium. 
 
 of ammonium. 
 
 salt. 
 
 
 hot water, precipitated 
 
 
 
 The solution be- 
 
 
 thence by sulphuric 
 
 
 
 comes colourless. 
 
 
 acid. 
 
 Arsenic (yellow). 
 
 Mercury* \ 
 
 and contains a 
 
 
 Silver, white, curdy, 
 
 Antimony (orange). 
 Tin* (brown or yellow). 
 
 ST+ <**> 
 
 ferrous salt. 
 
 
 soluble in ammonia, 
 precipitated thence by 
 
 Gold N ,, , . 
 ) (black- 
 Platinum [ , 
 
 Copper / 
 Cadmium (yellow). 
 
 Chromium as 
 chromate. 
 
 
 nitric acid. 
 
 I-T -j- -, ) brown j. 
 [Indium] ' 
 
 Bismuth (brown). 
 
 The solution be- 
 
 
 Mercury as subsalt, 
 white, finely-divided, 
 blackened by am- 
 monia. 
 
 Molybdenum f (brown). 
 [Selenium] (red-yellow). 
 [Tellurium] (black). 
 
 [ Palladium] J \ 
 [Osmium] ( (black- 
 [Khodium] I brown). 
 [Ruthenium] J 
 
 comes green, and 
 contains a chro- 
 mic salt. 
 
 
 * In a saturated solution 
 of a barium-salt, hydrochl. 
 acid gives a white precip. 
 readily soluble in water. 
 In an alkaline solution, 
 hydrochloric (or nitric) acid 
 gives a precipitate in pre- 
 sence of 
 Silicic x 
 
 * SnS is brown, SnS* yellow. 
 From the solution of SnS in 
 sulphide of ammonium, hy- 
 drochl. acid precipitates yel- 
 low SnS2. 
 + The sulphides of tungsten 
 and [vanadium} are not pre- 
 cip. by hydrosulph. acid from 
 an acid solution : but they are 
 when their solution in sul- 
 
 * Mercury as protcs.ilt is 
 precip. white by a little hy- 
 drosulph. acid; black by ex- 
 cess, 
 t Lead is only precip. com- 
 pletely from dilute, uot too 
 acid, solutions. 
 The sulphides of all the 
 platinum-metals are precipi- 
 tated very slowly. 
 
 * Sulphur is also 
 separated in presence 
 of free chlorine, bro- 
 mine, and iodine, of 
 sulphurous, nitrous, 
 hiipochlorous, chlo- 
 ric, iodic, bromic 
 acids, &c. : and gene- 
 rally in presence of 
 easily reducible salts 
 
 
 Boric 
 
 phide of ammonium is de- 
 
 
 of metals which arc 
 
 
 Antimonic ! ac j^ B . 
 
 composed by an acid. 
 
 
 not precip. as sul- 
 
 
 Tioifjstic [ 
 
 
 
 phides from an acid 
 
 
 Molybdic I 
 
 
 
 solution. 
 
 
 Benzoic ' 
 
 
 
 
 
 or of those metals whose 
 
 
 
 
 
 oxides are soluble in alkalis 
 
 
 
 
 
 (aluminium, &c., soluble in 
 
 
 
 
 
 excess of acid) ; or of cy- 
 
 
 
 
 
 anides and ferrocyanides; 
 
 
 
 
 
 or of those sulphides which 
 
 
 
 
 
 are soluble in sulphide of 
 
 
 
 
 
 ammonium. In presence of 
 
 
 
 
 
 soluble poll/sulphides or hy- 
 posulphites, sulphur is se- 
 
 
 
 
 
 parated. 
 
 
 
 
 
 The metals enclosed thus [ ] are very rare, and 
 
ANALYSIS INORGANIC. 
 
 219 
 
 Hydrosulphuric Acid, Sulphide of Ammonium, and Carbonate of 
 successively applied. 
 
 Sulphide of Ammonium. 
 
 Metals which are precipitated by sulphide of ammonium, in presence 
 
 of chloride of ammonium. 
 
 (The solution should be neutralised with ammonia before adding sulphide 
 
 of ammonium.) 
 
 r~ 
 
 
 \ 
 
 f 
 
 \ 
 
 As Sulphides : 
 
 As Oxides: 
 also precip. by ammonia. 
 
 As Salts: 
 also prec. by amm. 
 
 precipitate* 
 
 does not 
 precip. 
 
 Nickel* , 
 
 a. soluble in potash. 
 
 a. in presence of 
 
 Barium \ - 
 
 a. precipitable 
 
 Cobalt j (black). 
 
 Aluminium* ^ (colour- 
 
 phosphoric acid. 
 
 Strontium | 
 
 by phosphate 
 
 Iron ' 
 
 [Grlucinum] j less). 
 
 Magnesium (crys- 
 
 Calcium ' , 
 
 of ammonium 
 
 Uranium (black-brown). 
 
 Chromium (green). 
 
 talline). 
 
 as carbonates. 
 
 (and ammonia). 
 
 Manganese (flesh- red). 
 
 [Tantalum] f. 
 
 
 
 Magnesium 
 
 Zincf (white). 
 
 [Columbium or Nio- 
 bium.] 
 
 b. in presence of 
 phosphoric, ox- 
 
 
 (crystalline). 
 
 
 b. insol. in potash. 
 
 alic, boric or hy- 
 
 
 b. not precip. by 
 
 
 [Cerium] . 
 
 drofluoric acid. 
 
 
 phosphate of 
 
 
 [Lanthanum] \ 
 [Didymium] J ~ 
 [Yttrium] 1 J 
 
 Calcium* \ -^ 
 Strontium | 
 Barium ' & 
 
 
 ammonium. 
 Potassium. 
 Sodium. 
 
 
 [Erbium] s 
 
 as phosphates, ox- 
 
 
 Lithium.* 
 
 
 [Terbium] ( |" 
 
 alates, borates, 
 
 
 Ammonium. 
 
 
 [Zirconium] \ 
 
 or fluorides. 
 
 
 
 
 [Thorium] , 1, 
 
 
 
 
 
 Titanium / 
 
 
 
 
 * Sulphides of nickel and 
 cobalt are difficultly soluble 
 in acetic and dilute hydrochl. 
 acids. Sulphide of nickel is 
 slightly sol. in yellow sul- 
 phide of ammonium, forming 
 
 * In presence of phosphoric 
 acid aluminium is also precip. 
 as phosphate, sol. in potash, 
 t Soluble after fusion with 
 potash. 
 
 * The alkaline- 
 earthy phosphates 
 are insol. in potash, 
 sol. in acetic acid. 
 Oxalate of calcium is 
 insol. in acetic acid. 
 
 * The precipitation 
 is not complete unless 
 ammonia is added, 
 and the whole heated 
 to boiling. 
 
 * A concentrated 
 solution of a li- 
 thium-salt is pre- 
 cip. by phosph. sod. 
 on heating. 
 
 a brown solution. 
 
 
 
 
 
 t Sulphide of zinc is in- 
 
 
 
 
 
 soluble in acetic acid. 
 
 
 
 
 
 Carbonate of Ammonium. 
 
 Metals which are precipitated neither 
 by kydrosulphuric acid nor by 
 sulphide of ammonium. Car- 
 bonate of ammonium, in presence 
 of chloride of ammonium, 
 
 oot bo sought for except in special cases. 
 
220 ANALYSIS INORGANIC. 
 
 If wo suppose the case of a solution containing all the metals, it is obvious that, by 
 the successive application of each of these general reagents, we shall separate, first, by 
 hydrochloric acid, those metals whose chlorides are insoluble ; secondly, by hydrosul- 
 phuric acid, those metals whose sulphides are insoluble in dilute acids ; thirdly, by 
 sulphide of ammonium, those remaining metals whose sulphides or hydrates are 
 insoluble in neutral or alkaline liquids ; and lastly, by carbonate of ammonium, those 
 metals whose carbonates are insohible : so that at last we have only the alkaline 
 metals left in solution. In order, however, to effect the complete separation of each 
 group, the general reagents must be employed in the order above stated: for sulphide 
 of ammonium would precipitate those metals whose sulphides are insoluble in dilute 
 acids, as well as those whose sulphides are only insoluble in neutral or alkaline liquids ; 
 and carbonate of ammonium, if employed before the other reagents, would precipitate 
 most of the metals of Groups 1 and 2, their carbonates being also insoluble. 
 
 The following rules, the importance of which will be obvious on the least reflection, 
 must also be strictly observed. 
 
 1. The mineral acid employed to acidify the original solution (when it is not already 
 sufficiently acid), is either hydrochloric or nitric acid. Both are employed dilute, and 
 not in sufficient quantity to interfere with the formation of the sulphides of Group 1. 
 Hydrochloric is generally preferable to nitric acid : for it serves as a general reagent, 
 separating at once those metals which form insoluble chlorides. If nitric acid be em- 
 ployed, these metals will be found in the precipitate by hydrosulphuric acid. 
 
 2. The precipitation by each general reagent must be complete. To ensure this, 
 the reagent must be added gradually, allowing the precipitate to subside between each 
 addition, until no further precipitate is produced. In the case of hydrosulphuric acid, 
 the precipitation is complete when the solution, after agitation, still smells strongly of 
 the gas. Gentle heat facilitates the separation of precipitates in almost every case. 
 Arsenic (as arsenic acid), gold, platinum, iridium, rhodium, and molybdenum, are 
 precipitated very slowly by hydrosulphuric acid. Tungsten and vanadium are not 
 precipitated by hydrosulphuric acid from an acid solution : they are, however, included 
 in Group 1, because their sulphides (obtained by adding sulphide of ammonium and 
 then hydrochloric acid), are insoluble in acids, but soluble in sulphide of ammonium. 
 
 3. Each group, when precipitated, must be thoroughly freed by washing with water 
 from all members of the subsequent groups, which may be contained in the solution. 
 This washing is effected, according to circumstances, either on a filter, or by decan- 
 tation. If the precipitate contains any easily oxidable sulphides, a little hydrosul- 
 phuric acid must be added to the wash-water (if the sulphide is insoluble in dilute 
 acids, e. g. sulphide of copper), or a little sulphide of ammonium (if the sulphide is 
 soluble in dilute acids, e. g. sulphides of iron and manganese), in order to prevent the 
 partial oxidation of the sulphide by exposure to the air during the washing of the 
 precipitate. After the precipitation of each group, it is advisable to ascertain the 
 presence or absence of any members of the succeeding groups, by carefully evaporating 
 on platinum-foil a moderate quantity of the filtrate; if, after ignition, there is no 
 distinctly visible residue, non-volatile substances need not be looked for further. It 
 is obvious that, if these two precautions (complete precipitation and thorough washing) 
 be neglected, metals belonging to one. group are liable to be found among those of 
 another group ; and consequently, as the analysis proceeds, reactions will be obtained 
 which will be the source of great perplexity to the unpractised analyst. 
 
 Each group of metals having been separated by the application of general reagents, 
 the presence or absence of each member of each group is ascertained by means of 
 special or characteristic reagents. It seldom happens that the number of elements 
 contained in any inorganic compound exceeds ten or twelve : and in most cases some 
 distinct idea of the nature of its principal constituents is afforded by the results of the 
 preliminary examination. In metallic minerals and alloys, the heavy metals are 
 chiefly to be looked for : in silicates, the earthy, alkaline-earthy, and alkaline metals, 
 iron, and manganese. It frequently happens that important information may be 
 derived from the colour of a precipitate or of a solution. Thus solutions of cupric, 
 chromic, molybdic, and vanadic salts, are blue or green ; those of nickel-salts, green ; 
 those of ferrous-salts, light bluish-green ; those of chromates, gold-salts, ferric- and 
 platinic-salts, yellow, with a red or brown tinge ; those of cobalt-salts, red, &c. These 
 colours are not perceptible when the amount of metal present is very small, or when 
 they are masked by the presence of other metals, the colour of whose solutions is 
 complementary to them. 
 
 In order to show the systematic method by which the members of each group are 
 detected in presence of each other, we will now briefly go through the most important 
 groups mentioned in the table. 
 
 1. Precipitate produced by hydrochloric acid. Chloride of lead is soluble in a large 
 quantity of water, especially on boiling ; chloride of silver, in ammonia ; subchloride 
 
ANALYSIS INORGANIC. 221 
 
 of mercury is blackened by ammonia. (The addition of either hydrochloric or nitric 
 acid may produce a precipitate in presence of such acids, hydrates, cyanides, sulphides 
 &c., as are soluble in alkaline liquids, but insoluble in water; or a precipitate of 
 sulphur, in presence of a polysulphide or hyposulphite, or a white precipitate, readily 
 soluble in more water, in a saturated solution of a barium-salt.) 
 
 2. Precipitate produced by hydrosulphuric acid. 
 
 a. Portion soluble in alkaline sulphides. Sulphide of arsenic is soluble in acid sul- 
 phite of potassium or in sesquicarbonate of ammonium, the sulphides of antimony and 
 tin are not. When the three sulphides are dissolved in aqua-regia, and the solution is 
 introduced into a Marsh's apparatus, antimony and arsenic are detected by the behaviour 
 of their gaseous hydrogen-compounds ; tin, after its separation by zinc, by its solubility 
 in hydrochloric acid, and by the reaction of its solution with chloride of mercury. 
 
 b. Portion insoluble in alkaline sulphides. The precipitate is treated with nitric 
 acid : sulphide of mercury and sulphate of lead may remain undissolved. In the 
 solution, lead is detected by sulphuric acid ; silver, by hydrochloric acid ; bismuth by 
 its precipitation by ammonia, or by water if no excess of acid is present ; copper, by 
 the blue colour of its ammoniacal solution, or by ferrocyanide of potassium ; cadmium, 
 by the precipitation of its ammoniacal solution by hydrosulphuric acid, after the addi- 
 tion of cyanide of potassium. 
 
 3. Precipitate produced by sulphide of ammonium. The precipitate is digested with 
 excess of caustic potash in the cold : chromium, zinc, aluminium, and glucinum are found 
 in the solution. Of the metals contained in the residue : cobalt, nickel, and manganese 
 form soluble double salts with ammonia, and so are not precipitated by it : iron, uranium, 
 the rarer earthy metals, and alkaline- earthy phosphates, oxalates, &c., are precipitated 
 by ammonia, even in presence of chloride of ammonium. The hydrates of uranium and 
 the rarer earthy metals are readily soluble in carbonate of ammonium : ferric hydrate 
 is less soluble, and the alkaline-earthy salts are insoluble. Ferric salts are detected 
 by sulphocyanate or ferrocyanide of potassium ; the alkaline-earthy salts by appro- 
 priate characteristic reagents. 
 
 4. Precipitate produced by carbonate of ammonium. The metals which compose 
 this group (barium, strontium, calcium) are distinguished by the different solubility 
 of their sulphates, oxalates, chromates, &c. : and by the colours which they com- 
 municate to the blowpipe flame, or to that of burning alcohol. 
 
 5. The solution, after the successive application of the above general reagents, 
 can only contain magnesium and the alkaline metals. Magnesium is detected by its 
 precipitation by phosphate of ammonium ; the alkaline metals by the colour which 
 they impart to the blowpipe or alcohol flame, and by the different solubility of their 
 tartrates or chloroplatinates. Ammonium is always sought for in a separate portion of 
 the original solution : it is detected by the evolution of ammonia when any of its salts 
 are heated with a fixed alkali or alkaline earth. 
 
 Since hyposulphite of sodium is decomposed by the salts of most of those metals which 
 are precipitated by hydrosulphuric acid from an acid solution, a metallic sulphide being 
 precipitated, it has been proposed to employ this compound as a general reagent 
 instead of hydrosulphuric acid, and so to avoid the unpleasant smell of the latter. 
 This substitution, however, has not as yet been generally adopted. 
 
 Carbonate of barium may also be employed as a general reagent. "When a solution 
 containing metallic salts is shaken up with excess of this salt, in the cold : 
 
 Are precipitated. Are not precipitated. 
 
 Tin. Silver. 
 
 Gold. Lead. 
 
 Iridium. Iron \ 
 
 Khodium. Nickel 
 
 Palladium. Cobalt Us protosalte. 
 
 Platinum. Manganese J 
 
 Mercury. Zinc. 
 
 Copper. Cerium. 
 
 Bismuth. Yttrium. 
 
 Cadmium. Glucinum. 
 
 Aluminium. Magnesium. 
 
 Manganese ] Calcium. 
 
 Iron V as sesquisalts. Barium. 
 
 Uranium j Strontium. 
 
 Chromium, as sesquisalt, or as chromic acid. Ammonium. 
 Titanium,as titanic acid. Lithium. 
 
 Sodium. 
 
 Potassium. 
 
222 ANALYSIS INORGANIC. 
 
 Mercury, platinum, palladium, rhodium, iridium, and gold are precipitated by 
 carbonate of barium only when they are present as oxygen-salts, not when present as 
 chlorides, &c. Arsenic, antimonic, phosphoric, selenic, and sulphuric acids are not 
 precipitated by carbonate of barium until the solutions of their salts have been 
 acidulated with nitric or hydrochloric acid. Carbonate of barium is not much used as 
 a general reagent ; it is however employed with advantage for the separation of the 
 metals which are precipitated by sulphide of ammonium, since it precipitates com- 
 pletely those which are present as sesquisalts, while the protosalts remain in solution. 
 
 When, in the course of a systematic qualitative analysis, one or more members of 
 the different groups have been recognised as constituents of the substance under ex- 
 amination, by means of the reactions above enumerated, the results must be confirmed 
 by certain special reactions, which will be detailed at length in the articles devoted to 
 the several elements. 
 
 b. Examination for Acids. 
 
 The qualitative detection of acids, is, on the whole, more difficult than that of metals ; 
 still, with due care, it may be accomplished with great precision. In most cases, the 
 preliminary examination, as well as the nature of the metals already found, give infor- 
 mation as to what acids should especially be looked for. The knowledge of the 
 solubility of different salts, and of the reactions of their aqueous solutions with 
 vegetable colours, is of the greatest importance in this examination. By heating the 
 substance either alone or with concentrated sulphuric acid, the presence or absence of 
 organic and volatile inorganic acids is at once ascertained, these acids either volati- 
 lising undecomposed, or yielding volatile products of decomposition. For this pur- 
 pose, a small portion of the dry substance is heated in a test-tube (not to boiling) with 
 3 to 4 times its volume of concentrated sulphuric acid ; when, in the case of all acids 
 which are either volatile without decomposition, or are decomposed by sulphuric acid 
 at a high temperature, gases or vapours are evolved, the properties of which, in most 
 cases, indicate the nature of the acids present. 
 
 1. Non-volatile acids : whose compounds evolve no vapours when heated with sul- 
 phuric acid, the mixture not being blackened Silicic, Boric, Phosphoric, Sulphuric, 
 lodic, Arsenic, Selenic, Tungstic, Molybdic, Titanic acids. 
 
 2. Acids which evolve a coloured gas, the mixture not being blackened Hydriodic, 
 Hydrobromic, Bromic, Chloric, Hypochlorous, Nitrous acids. 
 
 3. Acids which evolve a colourless gas, generally possesses an irritating smell 
 and an acid reaction, the mixture not being blackened a. Volatile without decom- 
 position: Hydrosulphurie, Hydrochloric, Nitric, Acetic, Benzoic, Succinic, Hydro- 
 floric acids. The gas evolved is not inflammable, except in the case of hydro- 
 sulphuric acid b. Decomposed Cyanic, Chromic (evolves oxygen), Carbonic, 
 Sulphurous, Hyposulphurous, Polythionic, Oxalic, Formic, Hydrocyanic, Sulphocyanic, 
 acids, Ferro- and Ferri-cyanides. In most of these cases, the gas evolved is inflam- 
 mable. 
 
 4. Non-volatile organic acids: Tartaric, Kacemic, Citric, Malic, Tannic, Gallic, 
 Uric acids. The mixture is blackened, and carbonic and sulphurous anhydrides and 
 carbonic oxide are evolved. 
 
 The behaviour of a mixture of salts, when heated alone or with sulphuric acid, is 
 often different from that of each individual salt under the same circumstances. Thus 
 a mixture of a nitrate or chlorate with a salt of an organic acid, does not blacken when 
 ignited, but commonly detonates : a chloride, in presence of a nitrate, when heated 
 with sulphuric acid, evolves chlorine and red nitrous fumes ; in presence of a chromate, 
 red fumes of chlorochromic acid ; in a mixture of a sulphite and a nitrate, chlorate, 
 chromate, &c., the sulphurous acid is converted into sulphuric acid ; in a mixture of 
 a sulphide and a sulphite, the two acids decompose each other, sulphur being sepa- 
 rated, and the characteristic smell of each destroyed. Chloride and subchloride of 
 mercury, and chloride of tin are decomposed with difficulty, if at all, by sulphuric 
 acid. 
 
 From a solution containing volatile and non-volatile acids, the former may be 
 separated by distillation with dilute sulphuric acid. 
 
 The general reagents usually employed in the examination for acids in the wet way, 
 are chloride or nitrate of barium ; chloride of calcium ; a mixture of sulphate of mag- 
 nesium, ammonia, and ^chloride of ammonium ; sesquichloride of iron ; nitrate of silver ; 
 and indigo-solution. By these reagents, the most important acids are divided into the 
 following groups. 
 
 1. Acids which are precipitated by chloride of barium : 
 
 a. from a solution acidulated with nitric or hydrochloric acid Sulphuric, Selenic, 
 Fluosilicic acids. 
 
ANALYSIS INORGANIC. 223 
 
 b. From a neutral solution (the precipitate being soluble in acids) Sulphurous, 
 Phosphoric, Carbonic, Silicic, Hydrofluoric, Oxalic, Chromic, Boric, Tartaric, Citric, 
 Arsenious, Arsenic acids. The last five acids are not precipitated in presence of 
 ammoniacal-salts. 
 
 2. Acids which are precipitated by chloride of calcium : 
 
 a. From a neutral solution only (the precipitate being soluble in acetic acid) Phos- 
 phoric, Arsenic, Boric, Carbonic, Sulphurous, Tartaric, Citric acids, and Ferrocyanides. 
 
 1. From a neutral or acetic acid solution Sulphuric, Hydrofluoric, Oxalic, Kacemic 
 acids. 
 
 3. Acids which are precipitated by sulphate of magnesium, in presence of ammonia 
 and chloride of ammonium Phosphoric, Arsenic, Tartaric acids. 
 
 4. Acids which are detected by sesquichloride of iron : 
 
 a. Are precipitated Ferrocyanides (from a solution containing free hydrochloric 
 acid): Phosphoric, Arsenic, Tannic acids (from a neutral or acetic acid solution) : Boric, 
 Benzoic, Succinic acids (from neutral solutions only). 
 
 b. Are coloured In presence of free hydrochloric acid; Ferricyanides (brown), Sul- 
 phocyanic acid (red). In neutral solutions only : Acetic, Formic, Sulphurous, Meconic 
 acids (red) : Gallic acid (black). 
 
 5. Acids which are precipitated by nitrate of silver : 
 
 a. From neutral solutions only (precipitate being soluble in dilute nitric acid) 
 Phosphoric, -Pyro- and Meta-pbosphoric, Arsenic, Arsenious, Chromic, Oxalic, Boric, 
 Tartaric, Citric, Sulphurous, Formic acids : Silicic and Acetic acids from concentrated 
 solutions. 
 
 b. From acid solutions also (the precipitate being insoluble in dilute nitric acid). 
 Hydrochloric, Hydrobromic, Hydriodic, Hydrocyanic, Sulphocyanic, lodic, Hydro- 
 sulphuric acids, and Ferro- and Ferri-cyanides. 
 
 6. Indigo-solution is decolorised, without the addition of an acid, by free chlorine 
 and bromine ; by all the oxygen-acids of chlorine, when free, and by metallic hypo- 
 chlorites ; by free nitric acid, if not too dilute, by alkaline sulphides, and by caustic 
 alkalis. On addition of sulphuric acid, and heating, by chlorates, bromates, iodates, 
 and nitrates. On addition of hydrochloric acid, and heating (chlorine being evolved), 
 by all the foregoing compounds ; also by chromates, selenates, tellurates, vanadates, 
 manganates, permanganates, ferrates, and all peroxides. 
 
 In investigating the acids contained in a soluble compound, the first step is to as- 
 certain the behaviour of the solution to vegetable colours. When, as is frequently the 
 case, a neutral solution is required, the solution, if acid, is neutralised by ammonia : 
 if alkaline, by nitric acid, or, if nitrate of silver be not employed as a reagent, by 
 hydrochloric acid. But, as many of the heavy metals, as well as some alkaline-earthy 
 salts, are precipitated when their solution is neutralised by ammonia, it is generally 
 necessary to remove from the solution all metals except the alkaline metals, before 
 proceeding to test for acids ; in which process, the presence or absence of metallic acids, 
 and of alkaline-earthy phosphates, oxalates, &c. will be ascertained. When this is 
 not done, it is frequently necessary to substitute for the general reagents mentioned 
 above, the nitrate of the same base, since nitric acid forms no insoluble salts : thus 
 nitrate, instead of chloride, of barium, must be employed in solutions containing lead, 
 silver, or subsalts of mercury. We have already mentioned cases in which the addition 
 of nitric or hydrochloric acid to an alkaline solution will produce a precipitate. The 
 following acids are also precipitated by the mere acidulation of their alkaline solutions : 
 Tungstic, Molybdic, Antimonic, Benzoic, Uric acids ; Boric and Silicic acids from con- 
 centrated solutions. Under the same circumstances, a precipitate of sulphur is produced 
 in presence of hyposulphurous acid or polysulphides : of iodine, in a solution containing 
 an iodide and an iodate : of acid tartrate of potassium or ammonium, in a solution 
 containing the normal tartrates of these metals. The nature of the metals found in 
 a solution will often imply the absence of one or more acids : generally speaking, a 
 neutral or acid solution containing one of the metals whose salts are used as general 
 reagents for acids, need not be examined for any of those acids which are precipitated 
 by that metal. Thus, sulphuric or hydrochloric acid need not be sought for in soluble 
 compounds containing barium or silver respectively. In order not to overlook the 
 presence of uncombined volatile organic acids, the acid solution is neutralised with 
 carbonate of sodium, evaporated to dryness, and ignited : when the organic acid, which, if 
 free, would have been volatilised undecomposed, is decomposed, with separation of 
 carbon. 
 
 Substances which are insoluble in water or acids are rendered soluble by one of the 
 methods already described, and the solution is examined for acids in the wet way. In- 
 soluble compounds of the heavy metals are mostly decomposed by digestion with 
 
224 ANALYSIS INORGANIC. 
 
 sulphide of ammonium ; sulphates of strontium and calcium by digestion with carbonate 
 of sodium : in both cases, the filtrate contains the acid, together with an excess of the 
 decomposing agent, while the metal is found in the residue. Insoluble salts of organic 
 acids are decomposed by boiling with an alkaline carbonate ; ferric salts of volatile 
 organic acids by digestion with ammonia : in both cases, the filtrate contains an alkaline 
 salt of the acid. Sulphides and all salts of the lower oxygen-acids of sulphur, yield 
 sulphuric acid when digested with nitric acid, or any other oxidising agent. 
 
 The application of confirmatory tests is as necessary in the case of acids as in that 
 of metals. F. T. C. 
 
 The methods of quantitative inorganic analysis cannot be included in one article. 
 The processes for the separation and quantitative estimation of each element are de- 
 scribed in the article devoted to that element. The analysis of ashes, soils, mineral- 
 waters, &c. and volumetric analysis, are also described in separate articles. We may 
 here however describe a method, of general application, which is found useful in many 
 cases, viz. : 
 
 The Indirect method of Quantitative Analysis. The usual method of de- 
 termining the quantities of the several constituents of a compound or mixture, is to 
 separate each of them in the form of a definite compound, which can be collected and 
 weighed, e. g. silver as chloride, barium as sulphate, &c., and calculate the weight of 
 the required constituent from the known composition of this compound. It sometimes 
 happens however, that the complete separation of certain substances is very difficult, 
 or even impossible, and in that case, recourse is had to a method of determination, 
 which depends on the general principle that any number of unknown quantities may 
 be determined simultaneously, if we can find between them a number of relations 
 equal to that of the quantities themselves ; in other words, n unknown quantities may 
 be determined by means of n equations. 
 
 Suppose for example, we have a mixture, either solid or liquid, containing potassium 
 and sodium, in the form of hydrates or carbonates. Take two equal portions of the 
 mixture (it is not necessary to know the weight of these portions), convert one portion 
 into chlorides, the other into sulphates, and weigh the two products. Let the sum of 
 the weights of the chlorides be a, and that of the sulphates b : the unknown weight 
 of potassium x, and that of sodium y ; then from the known atomic weights of the 
 metals, their chlorides and sulphates, we have : 
 
 74-5 58-5 
 
 39" * + sr y - a 
 
 87 71 
 
 39 * + 23 y = b 
 
 whence the quantities x and y may be determined. 
 
 Another form in which the indirect method may be applied to the determination of 
 two substances, is to bring them both together into a form in which they can be 
 weighed, e. g. as chlorides or sulphates, and determine the.quantity of chlorine or of 
 sulphuric acid in the mixture ; thus, suppose a mixture of potash and soda to be con- 
 verted into chlorides : let the sum of the weights of these chlorides be s, and let the 
 amount of chlorine in this mixture, determined as chloride of silver, be c ; then if x be 
 the quantity of potassium and y the quantity of sodium, we have the two equations : 
 
 KC1 NaCl Cl Cl 
 
 ET* + -Na^ = * ; K* + K& y =C 
 
 74-5 38-5 35-5 35-4 
 
 or 3T-* + 2T^ -* ; Z9-* + W- y = s 
 
 whence x and y may be found. 
 
 If three substances are to be determined, e. g. barium, strontium, and calcium, we 
 should of course require three equations, which, in the case supposed, might be obtained 
 by weighing the three substances, first as carbonates, then as oxalates, then as sul- 
 phates. It is seldom, however, that the indirect method is applied to the determination 
 of more than two substances. 
 
 A case in which this indirect method of analysis is often applied, is to the deter- 
 mination of a small quantity of bromine or iodine in presence of chlorine, as in the 
 analysis of mineral waters. The chlorine and bromine are precipitated by a solution 
 of silver, and the mixed chloride and bromide of silver is weighed. It is then ignited 
 in a stream of chlorine till all the bromine is expelled, and the resulting chloride is 
 again weighed : let the difference of the two weights be d : then, since chlorine and 
 
ANALYSIS (ORGANIC). 225 
 
 bromine replace one another in the proportion of their atomic weights, viz. as 
 35-6 to 80, we have : 
 
 35-5 _ 44-5 ,, 
 
 whence Br - an Br = d; ^ Br = d. 
 
 o() ou 
 
 and therefore Br = 1797 d. 
 
 The indirect method of analysis can only be employed with advantage to ascertain 
 the relative quantities of substances whose atomic weights differ considerably : with a 
 mixture of bodies of the same atomic weight, it cannot give any definite result ; in 
 fact the two equations which it involves become in that case identical. 
 
 ANALYSIS (ORGANIC). The analysis of organic substances divides itself, 
 like that of inorganic bodies, into qualitative and quantitative. A further division is 
 also convenient, viz. into Elementary or Ultimate Analysis and Proximate analysis, 
 according as the object of the inquiry is to determine the ultimate elements, carbon, 
 hydrogen, &c., of which the body is composed, or the proximate principles, such as 
 sugar, starch, fibrin, &c., in which those elements are grouped. 
 
 I. ELEMENTARY OB ULTIMATE ORGANIC ANALYSIS. 
 
 Organic bodies are composed of carbon, hydrogen, and oxygen, with or without 
 nitrogen, sometimes also associated with sulphur and phosphorus : these are all the 
 elements that occur in natural organic compounds ; those which are artificially prepared 
 may contain any elements whatever. 
 
 The detection and estimation of these elements depends essentially on the process 
 of COMBUSTION. "When an organic compound is heated to redness in contact with free 
 oxygen, or with a substance which gives up that element with facility, it is com- 
 pletely decomposed, its elements being separated either in the free state or in new 
 forms of combination. 
 
 Qualitative Analysis. Carbon and Hydrogen are detected by burning the 
 compound in a glass tube in contact with oxide of copper or chromate of lead. The 
 carbon is then converted into carbonic acid*, which if passed into baryta-water, forms 
 a white precipitate of carbonate of barium, and the hydrogen into water, which collects 
 in drops in a small cooled receiver attached to the combustion-tube, or, if in very small 
 quantity, may be rendered visible by causing the vapour to pass through a narrow 
 glass tube lined with phosphoric anhydride, which if water is present, will be con- 
 verted into phosphoric acid and dissolved. Carbon may also, in nearly all cases, be 
 detected by the black residue which remains when the organic substance is burned in 
 the air, or ignited in a close vessel, or heated with strong sulphuric acid ; very few 
 organic bodies contain sufficient oxygen to burn away the carbon completely, even in 
 contact with the air. The black residue of carbonaceous matter may be distinguished 
 from black substances of inorganic origin, by burning slowly away when heated to 
 redness, and by its property of deflagrating with nitre and chlorate of potassium. 
 
 Nitrogen in organic bodies ia for the most part given off in the free state when the 
 compound is burned with oxide of copper, but a surer mode of detecting it, especially 
 when in small quantity, is to heat the substance in a test-tube with a considerable 
 excess of hydrate of potassium or sodium. The carbon is then converted into car- 
 bonic acid by the oxygen of the alkaline hydrate, while the whole or the greater 
 part of the hydrogen unites with the nitrogen to form ammonia, which may be detected 
 by its odour, by its action on litmus paper, and by the white fumes which it produces 
 when a glass rod dipped in dilute hydrochloric acid is held over the mouth of the 
 tube (see AMMONIA). A still more delicate test for nitrogen is the following, given by 
 Lassaigne. A portion of the organic compound is fused in a test-tube with a small 
 piece of potassium ; the mass is treated with water when cold ; and the liquid boiled 
 with protosulphate of iron partially oxidised by contact with the air. If it be then 
 supersaturated with hydrochloric acid, the presence of nitrogen will be indicated by 
 the formation of a precipitate of Prussian blue, or in case of very minute quantities, by 
 a bluish green colour being communicated to the solution. 
 
 Chlorine in organic bodies is detected by igniting the compound with quick lime, 
 whereby it is completely destroyed, the chlorine uniting with the calcium, in which 
 state of combination it may be dissolved out by water, and the chlorine precipitated 
 by nitrate of silver. In some organic compounds which contain hydrochloric acid 
 ready formed, viz. the hydrochlorates of the organic bases, the chlorine may be imme- 
 diately detected by nitrate of silver without this preliminary treatment. 
 
 * Throughout this article, the term carbonic acid is used for CO 2 , in accordance with established 
 usage, instead of the more correct appellation carbonic anhydride. 
 
 VOL. L Q 
 
226 ANALYSIS (ORGANIC) 
 
 Bromine and Iodine may be detected by similar treatment ; Fluorine in the same 
 manner as in inorganic bodies. 
 
 Sulphur, Phosphorus, and Arsenic, are detected by igniting the organic compound 
 with a mixture of hydrate of potassium, and nitre or chlorate of potassium, whereby 
 those elements are converted into sulphuric, phosphoric, and arsenic acids, the 
 presence of which may be demonstrated by reactions appropriate to each. 
 
 Metals occurring in organic compounds, remain for the most in the form of oxides, 
 or in the metallic state when the organic matter is burnt. Mercury may be detected 
 in the ordinary way, by distillation with lime. 
 
 Quantitative Analysis. The first quantitative analyses of organic bodies were 
 made by Gray-Lussac and The"nard. The substance to be analysed was mixed with a 
 known weight of chlorate of potassium, and made up into small pellets, which were 
 dropped one by one through a stopcock of peculiar construction, into an upright glass 
 tube heated to redness, the gas thereby produced escaping by a lateral tube and being 
 collected over mercury. The volume of gas was exactly measured, and the carbonic 
 acid absorbed by caustic potash. The remaining gas consisted either of pure oxygen, 
 or (in the case of azotised bodies) of a mixture of oxygen and nitrogen, the propor- 
 tions of which were determined eudiometrically (see ANALYSIS OF GASES). Knowing 
 then the weight of the substance burned, the weight of the chlorate of potassium used, 
 and consequently the quantity of oxygen evolved, also the quantity of carbonic acid 
 produced, and of the oxygen remaining after its absorption, sufficient data were obtained 
 for calculating the amount of carbon, hydrogen, and oxygen in the substance analysed : 
 for, the difference between the total quantity of oxygen which had disappeared, and 
 that which was consumed in burning the carbon (this latter quantity being equal in 
 volume to the carbonic acid produced), gave the quantity which had united with the 
 hydrogen to form water, and thence the amount of hydrogen was calculated. 
 
 This process was a great step in chemical science, and yielded many important 
 results ; but it was difficult of execution, requiring great skill on the part of the 
 operator ; it was also inexact in the case of nitrogenous bodies, and totally inapplicable 
 to liquid or volatile compounds. Berzelius simplified it by mixing the chlorate of 
 potassium with common salt, thereby causing the combustion to go on gradually, and 
 rendering it possible to introduce the whole of the material at once. He also collected 
 and weighed the water produced, and thus greatly simplified the calculation. 
 
 Saussure and Prout burned the organic substance in an atmosphere of oxygen. 
 Prout's apparatus was so contrived that the substance was burnt in a measured volume 
 of oxygen, and the volume of the gas remaining after combustion was compared with 
 the original volume. Now, since the volume of carbonic acid produced by the com- 
 bustion of carbon is equal to that of the oxygen consumed, while that which unites 
 with the hydrogen to form water disappears altogether, it follows that if the organic 
 substance contains oxygen and hydrogen exactly in the proportion to form water (as 
 in acetic acid, sugar, &c.), the volume of gas remaining after combustion will be equal 
 to that of the original oxygen : whereas if the proportion of hydrogen is greater (as in 
 alcohol and ether), the volume of gas will be diminished by the combustion ; and if 
 the proportion of hydrogen is less (as in oxalic acid), the volume of gas will be in- 
 creased. Hence, by absorbing the carbonic acid with potash and measuring the 
 residual gas, sufficient data were obtained for calculating the quantities of carbon, 
 hydrogen, and oxygen. 
 
 The method now universally adopted for the estimation of carbon and hydrogen in 
 organic compounds, consists in burning the compound with a large excess of oxide of 
 copper or chromate of lead, and determining the quantities of carbonic acid and water 
 produced by the combustion, not by measure but by weight, the water being absorbed 
 by chloride of calcium, and the carbonic acid by potash. The use of oxide of copper 
 was first introduced by Gray-Lussac and afterwards adopted by Ure ; but it is to Liebig 
 that we are indebted for those modifications of the process which have brought it to 
 its present state of simplicity and exactness. 
 
 The process, as now performed, requires the following materials and apparatus. 
 
 Oxide of Copper. Prepared by dissolving copper in nitric acid, evaporating to dry- 
 ness, and calcining the residual nitrate in a crucible at a low red heat. As thus 
 prepared, it is a dense, soft black powder, which rapidly absorbs water from the air 
 even before it is quite cold. If, however, it be very strongly heated, it aggregates 
 into dense hard lumps, which, when broken into small pieces and sifted from the finer 
 powder, yield an oxide well adapted for the combustion of volatile liquids. Oxide of 
 copper may also be prepared by igniting copper turnings in a muffle. The oxide thus 
 obtained is much harder and less hygroscopic than that prepared from the nitrate, 
 but it is not so easily mixed with an organic substance in the state of fine powder. 
 Oxide of copper must always be heated to low redness immediately before use. 
 
 Chromate of Lead. Prepared by precipitating a solution of acetate of lead with \a- 
 
ELEMENTARY OR ULTIMATE. 227 
 
 chromate of potassium, fusing the washed and dried precipitate in a crucible, and 
 pulverising it in an iron mortar ; it is then obtained in the form of a yellow-brown 
 powder. It is but very slightly hygroscopic ; but to ensure its complete dryness, it 
 should be preserved in stoppered bottles and heated over a lamp just before it is used. 
 
 Metallic Copper. Used in the analysis of bodies containing nitrogen. The most 
 convenient form is that of fine copper turnings, or thin foil rolled up into a spiral. As 
 the surface, especially of the turnings, is seldom clean, the metal should first be heated 
 in a current of air, to destroy any organic matter adhering to it, then pressed 
 into a combustion-tube, and heated in a current of dry hydrogen gas to reduce the 
 oxide previously formed, the heat being continued as long as vapour of water continues 
 to be given off, and the stream of hydrogen afterwards kept up till the metal is cold. 
 By this treatment, the surface becomes covered with finely divided copper, which is 
 very hygroscopic and must therefore be strongly heated over a lamp before use. 
 Finely divided copper reduced by hydrogen from the oxide, is not applicable, being 
 found to decompose carbonic acid at a red heat. 
 
 Combustion-tubes of hard glass. They must be capable of sustaining a strong red 
 heat without melting or even softening to such a degree as to be blown out by the 
 pressure of the evolved gases. The best are made of the hard Bohemian glass (silicate 
 of calcium and potassium), which may now be procured without difficulty. Glass 
 containing lead is utterly unfit for the purpose. When the temperature required for 
 a combustion is very high, the tube should be protected by wrapping it in copper foil 
 or brass wire-gauze, to prevent it from bending if it becomes softened by the heat. 
 
 The length and diameter of tube required vary according to the substance to be 
 burnt. For the combustion of ordinary solids, tubes of half an inch internal diameter, 
 and 18 inches long, are well adapted : for solids containing very little carbon, a diameter 
 of pj of an inch is sufficient : for liquids, it is necessary to use tubes ^ of an inch 
 wide and 20 or 30 inches long, the length being greater as the liquid is more volatile. 
 The use of tubes of larger dimensions than the particular case requires, is not to be 
 recommended, as it involves waste of oxide of copper and increases the unavoidable 
 errors of the operation. 
 
 The tubes, after being thoroughly cleansed and dried, are drawn out into an inclined 
 neck, and sealed at one end, 
 
 while the other end is cut as Fig. 8. 
 
 evenly as possible with a - -- , 
 
 file, and afterwards made 
 smooth at the edges by care- 
 ful heating in the blowpipe 
 flame. The best mode of 
 sealing is to take a tube of 
 double the length required, 
 soften it in the middle by 
 means of a powerful blow- / 
 pipe flame, then draw it out j 
 in the manner shown in fig. 8, 
 and apply the point of the flame for an instant at the middle of the neck a, so 
 as to divide and seal it. By this means, two tubes of the required shape are made 
 at once. 
 
 Chloride of calcium tubes. The chloride of calcium for absorbing the water gene- 
 rated in the combustion, is usually contained in a bulb-tube of the form shown in 
 fig. 9. The end a passes through a perforated 
 
 cork fitting into the combustion-tube, and Fig. 9. 
 
 the end b is fitted with a cork and narrow 
 glass tube, which is connected with the potash- 
 apparatus by means of a flexible tube of caout- 
 chouc. Small plugs of cotton-wool are placed 
 at c, d, to keep the chloride of calcium in its place. The cork d should be covered 
 
 nX ' ^ ***** * ** *** ^ " absor P tion 
 
 Another form of this apparatus presenting some advantages is the U-tube (fia 10} 
 having at the end nearest to the combustion-tube, a small test-tube, t, which serves to 
 
 ^]T^A^t^*^>"^^^***rt^ does not get so 
 much wetted, and may be used several times without renewal. Chloride of calcium 
 tubes are sometimes also made in the form of a U-tube (fig. 1 1 ), having two bulbs, the one 
 
 er be n^ 7 f , ""^ ^ ^ ^^ ^ with chloride f <*lcium, and the 
 upper being empty to receive the greater part of the water. This form of tube 
 
 that iast 
 
 c2 
 
228 
 
 ANALYSIS (ORGANIC) 
 
 The U-tube must always be used in preference to the straight tube (fig. 8), 
 when the combustion is made in a stream of oxygen gas ; because the current of gas 
 being then rather strong, is apt to carry the vapour of water through the straight 
 tube so quickly that a portion of it escapes uncondensed, whereas the U-tube 
 detains it longer, and is more likely to ensure complete absorption. 
 
 Fig. 10. 
 
 Fig. 11. 
 
 Fig. 12. 
 
 The chloride of calcium should be in the spongy state in which it is obtained by 
 drying at about 200 C. The fused chloride is not so good for the purpose, because it 
 often contains free lime, which absorbs carbonic acid as well as water. 
 
 Potash-bulbs. The solution of caustic potash 
 which absorbs the carbonic acid, is contained in 
 a Liebig's bulb-apparatus (fig. 12), the form of 
 which is so contrived as to keep the bubbles of gas 
 in contact with the solution for a considerable time, 
 without using a long column of liquid. The large 
 bulb a, is connected with the chloride-of-calcium 
 tube, the other extremity of the apparatus being 
 left open. The solution of potash should have a 
 density of about 1-27. If a weaker ley be used, 
 the carbonic acid will not be completely absorbed, 
 and stronger ley is apt to froth, and in that case 
 a portion of it is sure to be forced out at the open 
 end of the apparatus, thereby annihilating the re- 
 sult of the experiment. To fill the bulbs, the potash 
 solution is poured into a small beaker or crucible, 
 and drawn into the apparatus by means of a small 
 suction- tube (fig. 13), attached to one end by means 
 of a perforated cork The quantity of liquid introduced should be sufficient to nearly 
 fill the three lower bulbs, not more : the apparatus thus filled weighs from 40 to 50 
 grammes. Before weighing, it must be carefully wiped on the 
 outside; and the inside of the tube, by which the liquid has 
 entered, must be dried by means of a thin roll of filtering paper. 
 Corks. The connection between the combustion-tube and the 
 chloride of calcium tube, is made by a perforated cork. The 
 greatest pains should be taken to select for the purpose good 
 corks, smooth, and free from flaws. They should be softened by 
 beating or by pressure. Immediately before the combustion, 
 the cork must be thoroughly dried in an air-bath or sand-bath at a temperature a 
 little above 100 C.: too great a heat must be avoided, as it renders the cork brittle. 
 Caoutchouc-tubes. The chloride-of-calcium tube is connected with the potash- 
 apparatus by a flexible tube of caoutchouc. These tubes are easily made by binding a 
 piece of sheet-caoutcb.ouc over a glass rod or tube of the proper size, and cutting it 
 with a single stroke of a pair of scissors. If the edges be then pressed together, a per- 
 fectly tight tube will be made. The connections are made air-tight by tying with 
 silk cord. Tubes of vulcanised caoutchouc, which may be purchased ready made, may 
 also be used, and if of such a size as to require some force to fit them to the tubes, 
 they make an air-tight joint without tying ; they must however always be previously 
 digested with a moderately strong solution of potash, in order to remove the sulphur, 
 which is otherwise apt to get into the chloride of calcium tube and potash-apparatus. 
 
 Combustion-furnaces. The combustion-tubes are heated either with charcoal or 
 with coal gas : formerly charcoal was the only fuel employed ; but gas-furnaces are 
 
 Fig. 13. 
 
ELEMENTARY OR ULTIMATE. 
 
 229 
 
 now coming into general use. Furnaces have also been constructed for burning spirit, ; 
 but the high price of that material in most countries renders its use -very limited. 
 
 The charcoal-furnace is made of sheet iron, in the form of a trough (Jig. 14), 22 to 
 24 inches long, and 3 inches high. The bottom is 3 inches wide, wth narrow aper- 
 tures about i an inch apart, which form a sort of grate ; the sides of the furnace are 
 inclined outwards, and 4| inches apart at top. To support the combustion-tube, pieces 
 of strong sheet-iron of the form D (fig. 15), are riveted to the bottom of the furnace at 
 
 Fig. 14. 
 
 Fig. 15. 
 
 intervals ; they are of exactly equal height,, with their edges ground flat, and correspond 
 with the round aperture in front of the furnace A. The furnace is placed upon flat bricks, 
 so that but little air can enter the grating unless the whole is purposely raised ; the 
 draught can thus be regulated at pleasure. The heat produced by the charcoal fire 
 is very regular, and may be raised to any degree required, higher indeed than the 
 best combustion-tubes can bear ; on the other hand, the use of charcoal as fuel has 
 many inconveniences; the operator is exposed to great heat and to the deleterious 
 fumes of carbonic oxide, and the ash flies about to such an extent that it is always 
 necessary to perform the combustions in a room apart from the general laboratory. 
 
 For these reasons, it has long been considered desirable to use coal-gas as the fuel 
 for the combustion process, and several forms of furnace have been contrived for the 
 purpose. It is only lately, however, that the problem has received a satisfactory 
 solution, viz. in the gas furnace constructed by Dr. Hofmann, and described by him in 
 the Journal of the Chemical Society, vol. xi. p. 30, whence the following details and 
 illustrations are taken. 
 
 In using coal-gas as fuel, it is essential that the gas while burning be mixed with 
 air in sufficient quantity to ensure complete combustion and prevent smoking. This 
 is usually effected by interposing a sheet of wire gauze between the flame and the orifices 
 from which the gas issnes. This contrivance was indeed adopted in a form of furnace 
 for organic analysis invented some years ago by Dr. Hofmann, and has also been 
 adopted by others. But all furnaces thus constructed are very liable to get out of 
 order, in consequence of the speedy destruction of the wire gauze ; moreover, they 
 do not afford sufficient heat for many combustions : hence they have not come into 
 general use. 
 
 In the new form of gas furnace, the mixing of the gas with air is attained by causing 
 it to issue through a number of small orifices placed very close together. For this 
 purpose, a peculiar form of burner is used, 
 
 Fig. 16. 
 
 called atmopyre (fig. 16). It consists of a 
 hollow cylinder of burnt clay, closed at top, 
 open at bottom, and having numerous per- 
 forations in the sides. Those which are 
 used for the combustion-furnace, are 3 
 inches high, | of an inch in external, and 
 | internal diameter. The perforations, of 
 about the thickness of a pin, are made in 
 rows, each cylinder having 10 rows of 15 
 holes each. From such a clay cylinder 
 loosely fixed upon an ordinary bat's wing 
 burner, the stopcock of which has been 
 properly adjusted, the gas burns with a 
 perfectly blue smokeless flame, which en- 
 velopes the cylinder and soon renders it 
 incandescent. 
 
 The disposition of the apparatus is shown 
 in fig. 17. Into a brass tube a, from 3 feet to 3 feet 
 8 inches long, and 1 inch in diameter (shown in section 
 in the figure), which communicates at both ends with 
 the gas-main of the laboratory, there are screwed from 
 24 to 34 tubes b. These tubes, an inch wide and 
 7 inches high, are provided with stopcocks and carry 
 brackets c c, f an inch long, and f of an inch in diameter, 
 for the reception of five ordinary bat's wing burners (each consuming from 3 to 
 
 Q 3 
 
 a. Horizontal gas pipe. 
 
 6. Vertical gag pipe provided 
 
 with stop cock, 
 c c. Brackets for burners. 
 d ddd. High clay burners. 
 e. Low clay burners. 
 /. Combustion tube. 
 g g. Wrought iron frame. 
 /(A. Cast iron supports. 
 f f. Ca<t iron footplate. 
 kk. Sides of fire-clay. 
 II. Cover plates of fire-clay. 
 
230 
 
 ANALYSIS (ORGANIC) 
 
 cubic feet of gas per hour, for a full luminous effect) upon which are fixed a corre- 
 sponding number of clay burners. These clay burners dddd, have the dimensions 
 above stated, excepting the middle one, which is only If inches high and has 70 or 
 80 perforations. It serves as a support for the combustion-tube /, which is thus 
 bedded in a channel of heated fire-clay. The system of brackets lying side by side, 
 acquires sufficient stability by a strong iron frame gg, which rests upon two firm 
 supports h h, of cast-iron, fastened down by screws upon the foot-plate, i ', likewise 
 of cast-iron. The iron frame g g, has moreover a groove for the reception of 
 moveable side plates of fire-clay 'k k. They are of the same height as the high 
 burners, over which they project about f of an inch, in consequence of their resting upon 
 the frame g ; lastly, 1 1 are covering plates, likewise of fire-clay, which are supported 
 by the side plates k k. 
 
 The whole disposition of this apparatus will be best understood by the perspective 
 view given mfig. 18. In the front part, contiguous to the potash-apparatus, the side 
 plates and the covering plates are omitted, in order to show the disposition of the 
 burners. During the combustion, however, all the burners are inclosed, as exhibited 
 in the posterior part of the apparatus. 
 
 iff. 18. 
 
 The efficiency of the furnace depends essentially upon the correct disposition of 
 the gas jets. The most appropriate space between the several burners, is about | 
 inch. It is very important for the attainment of a perfectly uniform temperature 
 that the several brackets bearing the burners should be equidistant. Their position is 
 therefore specially secured by every bracket being fixed in an aperture formed in the 
 iron frame gg, Jig. 17. 
 
 According to the length of the combustion-tube, from 8 to 10 stopcocks (under all 
 circumstances the largest possible number) are opened at once at the commencement 
 of a combustion. If care has been taken to regulate the amount of gas, either by 
 the stopcocks in the horizontal gas pipe, or by those in the separate supply-tubes, the 
 lighted portion of the furnace will, in 10 or 12 minutes, be in a state of perfect in- 
 candescence. After this it is only necessary to open the remainder of the stopcocks, 
 in appropriate succession, to insure a slow and regularly progressing combustion. The 
 time required for the completion of an analysis varies from 40 minutes to an hour, 
 rarely more. 
 
 The heat obtained by this furnace is very regular ; and since it is conveyed to the 
 combustion- tube chiefly by radiation from the incandescent mass of surrounding clay 
 every part of the tube is equally heated. The temperature which it is capable of 
 yielding is entirety at the command of the operator. When strained to its full 
 power, it, gives a heat equal to that of the strongest charcoal combustion-furnace ; but 
 by properly adjusting the stopcocks, it may be kept at any desired temperature, 
 especially since it is only necessary to look into the channel, when, with a little 
 practice, a correct idea of the temperature is rapidly obained from the colour of 
 the glowing cylinders. It deserves, however, to be noticed that the apparatus 
 furnishes rather more heat than is generally required ; it is preferable, therefore, 
 under all circumstances, to protect the combustion-tube by a metallic shield : for this 
 purpose ordinary brass wire gauze may be conveniently employed ; it is more easily 
 Tiianipulated, and may be used longer than the thin copper or brass plate generally 
 employed. 
 
 One great advantage of this furnace is its durability. The clay plates and burners 
 show but lit ile tendency to split, and fhe mixture of gas and air is so perfect that 
 
ELEMENTARY OR ULTIMATE. 231 
 
 the holes in the burners never become stopped up with carbon. Moreover, the cost of 
 the gas consumed is very much less than that of the charcoal required to produce the 
 same amount of heating effect. Dr. Hofmann has found that 
 a combustion lasting 1 hour, and requiring the whole length Fig. 19. 
 
 of the furnace (34 rows of burners), consumes from 80 to 90 _J L. 
 
 cubic feet of gas. For a carbon determination, with 24 rows 
 of burners, which generally lasts about 40 minutes, from 
 50 to 60 cubic feet are required, and for a nitrogen deter- 
 mination, 25 to 30 cubic feet. In laboratories where many 
 combustions are made, the saving of fuel soon covers the 
 original cost of the furnace. 
 
 The expense of the apparatus and the consumption of 
 gas, may be diminished by reducing the number of 
 rows of burners from 5 to 3, as shown in fig. 19. The 
 heat given by such a furnace is of course not so great as 
 that afforded by the larger one, but it is sufficient for nearly 
 all combustions. 
 
 Several other forms of gas furnace for organic analysis 
 
 have also been proposed. One of these invented by Babo, which is much used in the 
 German laboratories, is represented in fig* 26, page 235. 
 
 PREPARATION OF THE SUBSTANCE FOR ANALYSIS. 
 
 Before proceeding to determine the proportion of the elements in an organic com- 
 pound, it is necessary to ensure that the substance is in a perfectly pure and definite 
 state. It is but seldom that the processes of ultimate analysis can be advan- 
 tageously applied to complex organic mixtures ; only indeed when the proportion of 
 a single element is to be determined for commercial purposes, as in the valuation of 
 articles of food or of manures by the quantity of nitrogen which they contain. 
 
 In solids, uniformity and regularity of structure, whether crystalline or otherwise, is 
 in many cases the best test of purity : in such cases, examination by the microscope 
 is often of great service. Constancy of melting-point is also a test of the purity of 
 many substances, especially of fatty bodies. The purification of solids is generally 
 effected by recrystallisation from solution, or from the fused state, or in the case of 
 volatile bodies, by sublimation. In liquids, the chief test of purity is constancy of 
 boiling point, and purification is effected chiefly by fractional distillation. In all cases 
 a small quantity of the substance must be burnt upon platinum foil, in order to ascer- 
 tain whether it contains any inorganic matter ; if the organic body is pure, it will burn 
 without residue. If inorganic matter is present in considerable quantity, or if it forms 
 an essential part of the compound, as in the salts of organic acids, its quantity must be 
 exactly determined by burning a weighed portion of the compound. 
 
 Further, it is necessary before proceeding to the process of combustion, to free the 
 compound from hygroscopic water. For this purpose, a weighed quantity of the sub- 
 stance is heated for some time in a water-bath at 100, and then weighed again; if it 
 has lost weight, it is again heated and again weighed : and these operations are re- 
 peated till two successive weighings, between which the substance has been heated, 
 give the same result. The substance may then be considered dry. ' 
 
 Bodies which cannot bear a temperature of 100 C. without decomposition, may be 
 dried by placing them over a large dish containing strong sulphuric acid, and covering 
 the whole arrangement with a bell-jar; the desiccation is greatly accelerated by 
 placing the whole apparatus on the plate of the air-pump, and exhausting the air. 
 
 The same methods may be applied to determine the amount of chemically combined 
 water which exists in many compounds, the water of crystallisation of salts, for ex- 
 ample. Many bodies, however, retain their water with too great force to be over- 
 come by the means just mentioned. Such substances may be dehydrated by enclosing 
 them in a test-tube immersed in a water or oil-bath, while a current of dry air is 
 drawn through the tube by means of an aspirator. In some cases even this is not suffi- 
 cient, and the desiccation can only be effected by heating the substance in a tube 
 from which the air is exhausted by an air-pump, then introducing dry air, exhaust- 
 ing again, and so on, till the substance ceases to lose weight. (See EVAPORATION and 
 WATER.) 
 
 It is often, however, difficult to determine how much of the oxygen and hydrogen 
 existing in a compound exists in the form of water : for many substances, before they 
 give off all the water that can be eliminated by the methods above described, begin to 
 decompose and form new compounds. In such cases, the process of organic annlysis 
 must be applied to the compound in the hydrated state, and the quantity of water 
 estimated as nearly as possible by the phenomena which the substance exhibits when 
 heated, or by its chemical reactions. 
 
 Q 4 
 
232 ANALYSIS (ORGANIC) 
 
 Volatile liquids are dehydrated by leaving them for some time in contact with 
 lumps effused chloride of calcium and then distilling, the chloride of calcium being 
 however previously removed, as it might, when heated, give up some of the water 
 which it has absorbed. 
 
 The substance having been brought to the proper state of purity and dryness, may 
 now be subjected to the combustion process. 
 
 ESTIMATION OF CARBON AND HYDROGEN. 
 
 In Solids not containing Nitrogen. The substance being thoroughly dry and in 
 the state of fine powder, about 0*3 grm. (or 5 grains) is weighed out in a small test- 
 tube, or between two watch-glasses, the weighing being made exact to the tenth of a 
 milligramme (or -001 of a grain). The vessel and its contents are weighed together, 
 and after the substance has been removed, the vessel, with the small quantity of 
 matter adhering to it is again weighed. This weight deducted from the former gives 
 the quantity of substance used in the experiment. The combustion-tube after being 
 cleansed, if necessary, is made very hot in the sand-bath, and a long glass tube being 
 thrust into it, the air is sucked out so as to remove every trace of moisture. 
 
 The combustion may be made either with oxide of copper or with chromate of lead ; 
 the latter being the more easily managed, on account of its possessing little or no 
 hygroscopic tendencies, we shall describe its use in the first place: A quantity of the 
 chromate (previously fused and pulverised) sufficient to fill the tube, is heated over 
 a gas lamp till its colour changes to brown-red. When it has cooled, a small quan- 
 tity is poured into the tube, sufficient to fill about an inch of its length, and about two- 
 thirds of the remainder is poured into a clean dry porcelain mortar. The substance to 
 be analysed is then added to it, and the two are carefully mixed by gentle trituration. 
 The combustion-tube being then taken in the right hand, and the mortar in the left, 
 the mixture is transferred to the tube by a kind of screwing motion, the open end of 
 the tube being slightly inclined upwards after each addition, and the tube lightly 
 tapped against the side of the mortar to make the mixture descend. When nearly 
 the whole of the mixture has been thus introduced, a small quantity of fresh chro- 
 mate is poured into the mortar, triturated so as to rinse it, and then transferred to the 
 tube in the same manner. The remainder of the tube up to within an inch of the 
 end is filled with pure chromate. The contents of the tube are then shaken together 
 by a few gentle taps on the table, so as to leave a free passage throughout for the 
 evolved gas. The arrangement of the mixture in the tube is shown in jig. 20, where 
 
 Fig. 20. 
 
 a represents the pure chroraate, b the mixture, c the rinsings, and d the pure chromate 
 near the open end. 
 
 The tube is now laid in the combustion furnace, and the chloride-of-calcium tube 
 and potash-bulbs are attached to it in the manner already described, the potash- 
 bulbs resting on a folded cloth, and the outer bulb being slightly raised by placing a 
 cork under the apparatus at r. Fig. 21, represents the arrangement for burning 
 with charcoal. The disposition of the gas-furnace is shown in fig. 16, page 225. 
 
 Fig. 21. 
 
 Before commencing the combustion, the apparatus must be carefully examined to 
 ensure its tightness. For this purpose, a hot coal is held for a short time near the 
 
ELEMENTARY OR ULTIMATE. 233 
 
 inner bulb (m) of the potash apparatus, so as to rarefy the air and cause a few bubbles 
 to pass through the liquid. The coal is then withdrawn, and the apparatus left to 
 itself for about ten minutes. If all the joints are air-tight, the liquid will now rise 
 in the bulb m to a higher level than in the outer bulb, and will retain its position ; 
 but if any leak occurs, it will soon fall down to its original level. Should this be the 
 case, the leakage is most probably in the cork which fits into the combustion-tube, or 
 in the caoutchouc connector. To remedy this inconvenience without delay, it is well 
 to be provided with two or three well dried perforated corks and a good stock of 
 caoutchouc connectors. 
 
 The tightness of the apparatus having been established, the heat may now be 
 applied. The anterior portion of the tube containing the pure chromate is first 
 heated to redness, by laying red-hot charcoal round it (or turning on the gas jets im- 
 mediately under it). The charcoal furnace is provided with a moveable screen g, 
 (fig. 21), to prevent the heat from extending too quickly along the tube. When the 
 anterior portion is thoroughly red-hot, the pure chromate of lead at the closed end of 
 the tube must also be heated to redness, in order to burn any vapour that may diffuse 
 into that part of the tube, and to prevent its deposition on the drawn out point, 
 whence it would afterwards be difficult to remove (this precaution must be taken in 
 every combustion, by whatever process). The fire is slowly extended towards the fur- 
 ther extremity, each portion of the mixture being thoroughly burnt before the fire is 
 extended further. The combustion should be so regulated that the carbonic acid may 
 enter the potash-bulbs at a uniform rate, and in a succession of bubbles which may be 
 easily counted. If no nitrogen is present, these bubbles are, after a certain time, 
 completely absorbed by the potash ; but when an azotised body is burnt, bubbles of 
 nitrogen pass through the potash-solution during the whole process. 
 
 When the tube has been heated to redness throughout, the heat must be raised by 
 fanning the fire on the top, and admitting air below by slightly raising the furnace from 
 the bricks. As soon as the evolution of gas begins to slacken, the cork is removed 
 from under the potash-bulbs, and the apparatus brought into the horizontal position. 
 If the combustion has gone on well, the evolution of carbonic acid ceases all at once ; 
 if, on the contrary, the gas bubbles continue to pass slowly at intervals for a long time 
 after the tube has been thoroughly ignited, we may be sure that the combustion is 
 imperfect, most probably in consequence of the mixture not having been sufficiently 
 intimate, and that the quantity of carbon will be found deficient. 
 
 As soon as the evolution of gas ceases, the liquid begins to rise in the bulb m. 
 The coals must then be quickly removed from the end of the tube, and the point 
 broken off with a pair of nippers. If the passage through the tube is clear; the potash- 
 solution immediately falls to the same level in both bulbs : if it does not, there is a 
 stoppage in the tube, and no time must be lost in clearing it, by thrusting in a stout 
 iron wire from end to end ; otherwise the potash-solution will be sucked up into the 
 chloride of calcium tube, and the result will be entirely destroyed. To complete the 
 experiment, it is now only necessary to draw a stream of air through the apparatus, by 
 applying the suction-tube (fig. 13) to the extremity^, of the potash apparatus, so as to 
 draw the small portions of carbonic acid and aqueous vapour remaining in the tube 
 into the chloride of calcium tube and potash-bulbs. In doing this, however, a certain 
 precaution is necessary : for the broken end of the tube being surrounded with an 
 atmosphere of carbonic acid, a portion of this gas is likely to be drawn through the 
 
 Fig. 22. 
 
 tube it.-to the potash-solution, thereby making the proportion of carbon appear too 
 great, To prevent this, a long glass tube open at both ends is placed over the end of 
 
234 
 
 ANALYSIS (ORGANIC) 
 
 the combustion-tube, and supported in a slanting position, as in fig. 22, while the air 
 is being drawn through the apparatus. By this means, the air is drawn from a height 
 above the stratum of carbonic acid over the furnace. When the gas furnace is used, 
 this precaution is of course superfluous, as the flame can be extinguished at once. 
 
 Lastly, the chloride-of-calcium tube and the potash-bulbs are detached, left to cool 
 for about half an hoxir, and then weighed. The increase of weight of the potash-bull^ 
 gives the quantity of carbonic acid produced, and ^ of this is the quantity of carbon 
 in the substance analysed. The increase of weight of the chloride-of-calcium tube 
 gives the quantity of water produced, and | of this is the amount of hydrogen. Know- 
 ing then the quantities of carbon and hydrogen in a given quantity of the substance 
 analysed, it is easy to calculate the proportions of carbon and hydrogen in 100 parts. 
 If the quantities thus determined make up 100, the substance is a hydrocarbon ; if 
 there is a deficiency, and it is known that no nitrogen, sulphur, chlorine &c. is present, 
 the difference gives the percentage of oxygen. Examples of the calculation will be 
 given further on. 
 
 Combustion with Oxide of Copper. When the combustion is made with oxide of 
 copper instead of chromate of lead, particular precautions are required to prevent the 
 absorption of water during the mixing and filling of the tube. A quantity of the 
 oxide is heated to redness in a covered earthen crucible, and left to cool till it will 
 no longer burn a cloth in which the crucible is held. It is then mixed in a hot mortar 
 with the substance to be analysed, and the mixture is arranged in the tube between 
 two columns of pure oxide of copper, exactly as described for chromate of lead, the 
 whole operation being conducted as quickly as possible. Some substances, however, 
 will not bear mixing with hot oxide of copper ; and even when this can be done, the 
 oxide is sure to cool during the mixing sufficiently to cause an absorption of moisture 
 from the air : hence an excess of hydrogen in the result of the analysis. To obviate 
 this source of error, it is sometimes recommended to lay the tube, after filling, in a 
 trough of hot sand, and connect it with an air-pump, then introduce air dried by pass- 
 ing over chloride of calcium, exhaust again, and so on. This, however, is a trouble- 
 some complication of the process. A simpler method of preventing the absorption of 
 
 Fig. 23. 
 
 Fig. 24. 
 
 Fig. 25. 
 
 water, is to pour the oxide of copper, while still hot, into a long-necked flask (fig. 23), 
 closed by a perforated cork in which a chloride-of-calcium tube is inserted, leave 
 it to cool, and mix it with the organic substance in the combustion-tube itself. 
 The neck of the flask must be a little wider than the combustion-tube, so that 
 the latter will just pass into it (fig. 24): the oxide may then be transferred to the 
 tube without coming in contact with the air. A small quantity of the cooled oxide 
 is first introduced in this manner, then a portion of the organic substance is added, 
 and upon this a column of oxide about three inches long is poured in the same 
 manner as before. This portion of oxide is mixed with the organic substance by 
 stirring it with a clean iron rod (fig. 25), the extremity of which is bent into two 
 turns of a screw ; and when it is thoroughly incorporated, the rest of the substance is 
 introduced, then another column of oxide of the same length as before, and the stirring 
 is repeated. Lastly, the rest of the tube is filled with pure oxide, and the combustion 
 performed as above. This method of incorporation does not ensure so complete a mix- 
 ture of the substance with the oxide as trituration in a mortar; but it answers this 
 purpose sufficiently well in most cases. 
 
 Oxide of copper is in many respects more convenient for use than chromate of lead, 
 and indeed is more generally used for the combustion of substances which burn with 
 facility. It is more easily prepared, and when partially reduced by the combustion 
 process, may be restored to its original state by moistening it with nitric acid, and 
 
ELEMENTARY OR ULTIMATE. 235 
 
 heating it to low redness in a crucible. It then becomes denser and less hygroscopic, 
 and in every way better adapted for use : in fact, it improves in this respect by each 
 repetition of the treatment. Chromate of lead may also be reoxidised by digestion 
 with nitric acid and subsequent fusion ; but the pulverisation of the fused mass is a 
 very laborious operation. 
 
 On the other hand, there are many cases in which the use of chromate of lead 
 presents decided advantages, viz. in the combustion of substances which are very rich 
 in carbon or difficult to burn, such as fatty bodies, coal, graphite, indigo, &c. Such 
 bodies are never completely burned by oxide of copper, probably because, at the begin- 
 ning of the combustion, they give off combustible gases, which partially reduce the 
 copper in the neighbourhood of each particle, and leave behind a quantity of charcoal 
 no longer in contact with the oxide, and requiring an atmosphere of free oxygen to 
 burn it. Now chromate of lead fuses when the heat becomes strong, thus becoming 
 more intimately mixed with the combustible substance, and moreover gives off a 
 quantity of free oxygen, which effectually completes the combustion of the carbon. 
 Its efficiency may be still further increased by mixing it with about ~ of its weight 
 of acid chromate of potassium. 
 
 Organic salts (tartrates, acetates, &c.) of potassium, sodium, barium, strontium, or 
 calcium, if burnt with oxide of copper, also exhibit a considerable deficiency of carbon, 
 because the metal then remains in the form of a carbonate. This source of error may 
 be obviated by adding to the oxide of copper a quantity of phosphate of copper or 
 oxide of antimony sufficient to decompose the carbonate ; or, better, by making the 
 combustion with chromate of lead. 
 
 Combustion with Oxide of Copper in a stream of Oxygen. The oxygen may either 
 be evolved from chlorate of potassium placed in the combustion-tube, or in a vessel 
 connected with it ; or it may be previously prepared and supplied from a gas-holder 
 connected with the tube. 
 
 The simplest way of proceeding is to place at the closed end of the combustion -tube 
 about \\ inch of a mixture of 1 pt. of chlorate of potassium (or better of perchlorate) 
 and 8 pts. oxide of copper, previously heated over a lamp and introduced while hot ; 
 then half an inch of pure oxide of copper, then the mixture, and a column of pure 
 oxide as usual. The combustion is carried on in the ordinary manner, until the tube 
 is ignited as far as the pure oxide near the sealed end. Heat is then cautiously applied 
 to the mixture of oxide and chlorate, so as to evolve oxygen at a moderate rate. 
 The carbon is thereby completely burned, and if the supply of oxygen is sufficient, 
 the reduced copper is reoxidised. After the gas has passed through the potash-solu- 
 tion for a few minutes without being perceptibly absorbed, the bulbs and the chloride- 
 of-calcium tube may be detached, without breaking off the point of the combustion-tube, 
 and air drawn through them to displace the free oxygen, which would otherwise in- 
 crease their weight. 
 
 The stream of warm oxygen passing through the potash-solution is sure to carry 
 away a certain quantity of vapour of water. To prevent this, a small tube containing 
 lumps of fused potash should be attached to the bulb apparatus. The apparatus 
 with this addition usually weighs between 50 and 60 grammes. 
 
 In operating in the manner above described, there is, however, considerable danger 
 of the stream of oxygen becoming too rapid, and thereby carrying off the vapour faster 
 than it can be absorbed by the solid potash. 
 
 It is better, therefore, to supply the oxygen from a gas-holder. The combustion- 
 
 Fiq. 26. 
 
 tube is open at both ends, and the end , furthest from the potash-bulbs and chloride- 
 of-calcium tube is connected with two gas-holders (Jig. 26), one filled with atmospheric 
 
236 ANALYSIS (ORGANIC) 
 
 air, and the other with oxygen gas. The communication is made by means of a 
 T-tube provided with a cock, which renders it easy to connect either gas-holder with 
 the combustion-tube and shut off the other at the same time. The air and oxygen 
 before entering the combustion-tube, are made to pass through two U-tubes, one con- 
 taining pumice-stone soaked in sulphuric acid, to dry the gas, the other lumps of caustic 
 potash, to free it from carbonic acid. The combustion-tube may be heated either 
 _,. _ 7 with gas or with charcoal (the figure represents a 
 
 ^ l $' Babo's gas apparatus), and theimixture may be disposed 
 
 ~ """^ in the tube in the ordinary way. But instead of mix- 
 
 v 1 ^/ ing the substance with the oxide of copper, it is better 
 
 / / in many cases to place it by itself in a small boat of 
 
 platinum or porcelain b (fig. 27). 
 The combustion-tube is first filled to two-thirds of its length with oxide of coj 
 
 
 platinum or porcelain b (fig. 27). 
 
 its length wt oxe o copper, 
 which need not be previously ignited, the remaining third, nearest to the gas-holder 
 
 being left free to receive the boat. It is then laid in the furnace, and connected, in 
 the manner just described, with the gas-holder containing atmospheric air ; the oxide 
 of copper is heated to redness ; and a stream of dry air is passed through the tube so 
 as to remove every trace of moisture. The tube is then left to cool ; the boat con- 
 taining the substance is put into its place, a plug of recently ignited asbestos having 
 been previously introduced to prevent the oxide of copper from coming in contact with 
 it ; the chloride-of-calcium tube (U-shaped, see p. 228) and potash-bulbs are attached in 
 the usual manner, and the apparatus is connected with the gas-holder containing oxygen. 
 The oxide of copper is now once more heated to redness, and as soon as it is thoroughly 
 ignited, heat is very cautiously applied to the part of the tube containing the boat, a 
 slow stream of oxygen being passed through the apparatus, sufficient to prevent any 
 backward passage of the evolved gases, but not to cause any free oxygen to pass through 
 the solution of potash. If the oxide of copper exhibits a red colour, arising from 
 reduction, the heating of the substance in the boat must be discontinued till the copper 
 is reoxidised. When at length there is nothing left of the substance but black char- 
 coal, the heat may be increased and the stream of oxygen accelerated. In this manner 
 the combustion is soon completed ; and when the bubbles of gas appear to pass through 
 the potash without absorption, the process is continued in the same manner for a 
 few minutes longer, and the potash-bulbs and chloride-of-calcium tube are then de- 
 tached, after air has been passed through the apparatus for a little while to expel the 
 oxygen. Lastly, the stream of air is continued for a sufficient time to effect the com- 
 plete reoxidation of the copper, which is then ready for another experiment without 
 further preparation. 
 
 After the tube has cooled, the boat is taken out and reweighed. If any inorganic 
 matter remains in it, the quantity of this is at once ascertained if the weight of the 
 boat itself is previously known. 
 
 This method, when carefully conducted, gives very exact results : it ensures the 
 complete combustion of the carbon, and obviates all danger of an excess of hydrogen 
 arising from moisture in the oxide of copper. It likewise saves the trouble of igniting 
 the oxide of copper before the experiment, and afterwards treating it with nitric acid, 
 But to ensure a good result, especial care must be taken not to heat the substance in 
 the boat too suddenly ; otherwise combustible gases will be given off more quickly 
 than they can be burnt, and the analysis will be worthless. 
 
 Combustion of Liquids. Volatile liquids are enclosed in small glass bulbs with 
 narrow necks (fig. 28). The bulb is first weighed and then filled with the liquid, in 
 the same manner as a thermometer tube, viz. by gently warming the 
 Fig. 28. bulb so as to rarefy the air, and dipping the neck into the liquid, so that 
 as the air cools, a small quantity of the liquid may be forced up by ex- 
 ternal pressure. The bulb is then again heated till the liquid boils, the 
 end of the neck immediately plunged again into the liquid, and the heat 
 removed. The vapour now condenses and leaves a vacuum, into which 
 the liquid is forced up so as to fill the bulb and the greater part of the 
 neck. The neck is then sealed, and the bulb re-weighed. It is best to 
 use two bulbs, each containing about 400 milligrammes of liquid. 
 
 The analysis is made with oxide of copper : the coarse-grained variety 
 obtained by oxidising copper turnings in a muffle, or by breaking oxide 
 which has been hardened by strong ignition juto small lumps, and sifting 
 off the finer particles, is best adapted for the purpose, because it affords 
 free space for the passage of the vapours, whereas the fine-grained 
 oxide lies more compactly, and the greater part of the vapour passes 
 over the surface instead of finding its way between the. particles. For 
 the same reason, chromate of lea'}, which fuses into a mass, is not so well adapted for 
 
ELEMENTARY OR ULTIMATE. 237 
 
 the combustion of volatile liquids. The oxide of copper must be ignited in a crucible 
 and left to cool completely in a corked flask (p. 234). 
 
 ' The combustion-tube should be at least 20 inches long, very volatile liquids 
 requiring even a greater length. About an inch of the cold oxide is first poured in 
 through a wide-necked funnel ; one of the bulbs is then taken by the neck, a slight 
 scratch having been previously made on it with a file ; it is thrust into the tube, bulb 
 downwards, the neck broken off at the scratch, and both bulb and neck dropt into the 
 tube. About three inches more oxide is then added, the other bulb introduced in the 
 same manner, and the tube filled up with oxide of copper. This oxide is first heated 
 to redness, care being taken to proceed very gradually, and when the charcoal furnace 
 is used, to protect the bulbs by a screen. As soon as the oxide is well ignited, a hot 
 coal is approached to the nearest bulb, so as to volatilise a portion of the liquid, 
 especial care being taken not to drive it over too fast. When the first bulb is empty, 
 the heat is gradually extended ; the liquid in the second bulb is then distilled in the 
 same manner, and the combustion is finished in the ordinary way. As soon as the 
 distillation of the liquid commences, a few pieces of hot charcoal must be placed under 
 the point of the combustion-tube, to prevent the liquid from condensing there, as if 
 this occurs, considerable heat will be required to dislodge the liquid, and a sudden 
 burst of vapour is likely to take place. 
 
 The object of using two bulbs is to prevent too great a reduction of copper in the 
 neighbourhood of either of them ; when there is no longer any oxide close to the bulbs, 
 a deposition of carbon is apt to take place, and then a stream of air or oxygen is 
 required to burn it. Greville Williams, however, uses only one bulb, and drives all 
 the liquid, at the very commencement of the analysis, into a column of cold oxide of 
 copper about four inches long. This portion is not directly heated till the end of the 
 analysis, the liquid being volatilised by the heat conducted by the oxide. Finally, a 
 stream of oxygen is passed through the tube to burn the deposited charcoal. Volatile 
 liquids cannot be burned in a continuous stream of oxygen, because an explosive mix- 
 ture would be formed. 
 
 For extremely volatile liquids, like aldehyde, a different plan is adopted. Such 
 liquids are enclosed in a bulb having the form of a small retort, the neck of which, 
 previously sealed, is inserted into the 
 
 hinder extremity of the combustion-tube, Fig. 29. 
 
 which is drawn out and left open for the 
 purpose, the connection being made air- 
 tight by means of a caoutchouc tube. As 
 soon as the oxide of copper is ignited, the 
 sealed end of the retort is broken off by 
 pressing it against the combustion-tube, 
 and the liquid is volatilised by cautiously 
 applying the heat of the hand or of tepid water to the bulb. If the liquid is so volatile 
 a * to boil at the temperature of the room, the bulb must be immersed in ice, and the 
 evaporation regulated by removing the ice from time to time, and replacing it as soon 
 as the liquid begins to boil. 
 
 Fixed oils are weighed in a short test-tube, which is then dropped into the com- 
 bustion-tube, a small quantity of oxide of copper having been first introduced, and 
 by inclining the tube, the oil is made to spread itself over the sides for about half the 
 length, after which the tube is filled up with oxide of copper or chromate of lead. 
 Soft, easily fusible fats are treated in the same manner. Waxy bodies are weighed in 
 small lumps, then dropped into the combustion-tube, and spread over its surface by 
 fusion. Fatty and waxy bodies may also be placed in boats in the manner already 
 described (p. 236), and burnt with chromate of lead, or with oxide of copper in a stream 
 of oxygen. 
 
 Modification of the Combustion-process in particular Cases: 
 a. In bodies containing Nitrogen. When an azotised organic body is burnt, the 
 greater part of _the nitrogen is given off in the free state, together with the water 
 and carbonic acid; but a certain portion, varying according to the nature of the 
 substance and the manner in which the combustion takes place, is converted into nitric 
 oxide or one of the higher oxides of nitrogen. Now, if either of these compounds is 
 formed in the process of organic analysis, it will pass over with the carbonic acid, and 
 if not_ decomposed before it reaches the potash -ley, it wiU be absorbed by that liquid 
 and give rise to an error in the estimation of the carbon. Before, therefore, an organic 
 compound is subjected to the combustion process, it must be carefully examined for 
 nitrogen in the manner already described (p. 226), and if that element is found to be 
 present, the combustion must be made in such a manner as to ensure that the whole 
 of it shall be evolved in the free state. 
 
238 ANALYSIS (ORGANIC) 
 
 For this purpose a long combust ion-ttibe is taken, and after the mixture and the 
 pure oxide of copper have been introduced in the ordinary way, about five inches of 
 copper- turnings, prepared as described at p. 227, are placed at the open extremity. 
 This metallic copper must be heated in a sand or air-bath just before it is wanted 
 and introduced into the tube while still hot, as its surface is very hygroscopic. 
 The combustion is made in the ordinary way, the metallic copper being however first 
 heated to redness, and kept in a state of strong ignition during the whole process. 
 The nitrogen is then evolved in the free state, and passes through the potash-ley in 
 bubbles. 
 
 The combustion must be made with oxide of copper alone : if chromate of lead is 
 used, or a continuous stream of oxygen passed through the tube, the quantity of nitric 
 oxide formed is too large to be effectually decomposed, even by a very long column of 
 red-hot copper. Oxygen may, however, be passed through the tube at the end of the 
 combustion, being evolved for that purpose from chlorate of potassium (p. 235). The 
 more slowly the combustion is conducted, the smaller will be the quantity of nitric 
 oxide formed. 
 
 ]8. In bodies containing Sulphur. When organic bodies containing sulphur are 
 burned with oxide of copper, the sulphur is converted into sulphurous acid, which, if 
 not intercepted, will pass into the potash-solution together with the carbonic acid. 
 This may be prevented, by interposing between the chloride-of-calcium and potash- 
 apparatus, a tube containing peroxide of lead : the sulphur will then be retained in 
 the form of sulphate of lead. It is better however to make the combustion with 
 chromate of lead, placing in the front part of the tube a rather long column of pure 
 chromate, which is heated only to dull redness : the sulphur will then be retained in the 
 combustion-tube. 
 
 y. In bodies containing Chlorine. When chlorinated organic compounds are burnt 
 with oxide of copper, chloride of copper is formed, which being volatile, passes over 
 into the chloride of calcium tube, and renders the determination of the hydrogen 
 inexact. This source of error may be completely avoided by burning with chromate 
 of lead, the chlorine then forming chloride of lead, which is not volatile even at a red 
 heat. 
 
 Similarly with bodies containing bromine and iodine. 
 
 5. In bodies containing Inorganic Matter. If an organic body, when burnt in the 
 air, leaves a residue which gives off carbonic acid on being treated with acids, its 
 analysis by combustion with oxide of copper will not give exact results, because a part 
 of the carbonic acid will be retained in the ash, instead of passing into the potash-bulbs. 
 This is particularly the case with the organic salts of potassium, sodium, barium, 
 strontium, and calcium. If the residue were in all cases a neutral carbonate, its 
 quantity might be determined and the amount of carbonic acid contained in it added 
 to that" which is absorbed in the potash apparatus. But this is not the case, the 
 composition of the residue being variable, and depending on a variety of circumstances. 
 
 In such cases, the complete evolution of carbonic acid may be ensured in two ways : 
 either by burning with oxide of copper, and mixing the organic substances with ignited 
 phosphate of copper, boric anhydride, or oxide of antimony ; or better, by burning with 
 chromate of lead, the alkaline carbonate being then completely decomposed by the 
 chromic acid. When these organic salts are burnt in a platinum boat, in a stream of 
 oxygen (p. 231), the residue may be weighed, the quantity of carbonic acid in it 
 determined in the ordinary way, and added to that absorbed by the potash. 
 
 Amount of Error in the Estimation of Carbon and Hydrogen. By the 
 methods above described, the carbon may be determined within 0*2 per cent. The 
 error is generally in defect, in consequence of imperfect combustion ; sometimes, how- 
 ever, it is in excess, especially in azotised bodies. 
 
 The hydrogen may be determined yet more nearly, viz. within O'l per cent. The 
 error is usually in excess, arising from absorption of water from the air during the 
 mixing of the substance with oxide of copper. But if this be avoided, by making the 
 mixture in the tube itself, or if the combustion be made with chromate of lead, only 
 a very slight excess of hydrogen need be apprehended. When the substance is burnt 
 in the platinum boat (p. 231), the hydrogen sometimes comes out a little below the 
 theoretical quantity. 
 
 ESTIMATION OF OXYGEN. 
 
 Oxygen is usually estimated by difference, after all the other elements of the com- 
 pound have been determined directly. In compounds containing only carbon, hydro- 
 gen, and oxygen, this method is sufficiently accurate : for, the error of the carbon being 
 generally in defect, and that of the hydrogen in excess, the two nearly compensate 
 each other ; but when chlorine, sulphur, and other elements are present, the errors 
 
ELEMENTARY OR ULTIMATE. 239 
 
 upon all these being usually in the same direction, viz. in defect, the amount of oxygen 
 determined by difference is likely to be much too great. A good method of determining 
 oxygen directly is therefore a desideratum, more especially as it would afford a check 
 on the estimation of the other elements. 
 
 A. method of effecting this determination has been given by Baumhauer (Ann. 
 Ch. Pharm. xe. 228), and applied in one or two cases. A combustion-tube open at 
 both ends is fitted up in the ordinary way for the determination of carbon and hydro- 
 gen, and the two ends of the apparatus are placed in connection with graduated glass 
 tubes, the one at the hinder extremity of the combustion-tube being filled with oxygen, 
 so that, when the combustion is finished, a stream of oxygen may be passed through 
 the tube and re-oxidise the reduced copper. The apparatus is then left to cool, the 
 quantity of gas in the two tubes is read off, and compared with the quantity before the 
 experiment, due regard being paid to corrections for temperature and pressure. The 
 difference gives the quantity of oxygen taken up by the reduced copper. Now, the 
 quantities of carbonic acid and water produced by the combustion having been 
 determined, the amount of oxygen in this carbonic acid and water, diminished by the 
 quantity of oxygen which has disappeared, gives the quantity of oxygen contained in 
 the substance analysed: thus, if the amount of oxygen in the carbonic acid and water 
 were 10, and the quantity of oxygen absorbed by the copper were 7, the amount of 
 oxygen contained in the substance would be 3. 
 
 Baumhauer gives two analyses (of oxalic acid and oxalate of lead), in which the 
 oxygen was determined by this method with great exactness. As, however, the total 
 volume of gas in the apparatus (the combustion-tube, potash-bulbs, &c.) is not known, 
 but only the difference of volume before and after the experiment, the corrections for 
 pressure and temperature cannot be made with accuracy. For exact results, it is 
 therefore necessary that the pressure and temperature at the beginning and end of the 
 experiment should be nearly the same. 
 
 ESTIMATION OF NITROGEN. 
 
 The quantity of nitrogen in an organic compound is determined, either by burning 
 the compound with oxide of copper and metallic copper in the manner already described, 
 and measuring the quantity of nitrogen evolved, or by igniting the compound with 
 soda-lime, whereby the nitrogen is evolved in the form of ammonia, absorbing the 
 ammonia by hydrochloric acid and precipitating by dichloride of platinum. 
 
 When the nitrogen is evolved in the free state, it may be estimated in two ways. viz. 
 comparatively, that is, by comparison with the quantity of carbon in the compound, 
 previously determined ; or absolutely, that is, by direct measurement of the whole 
 quantity evolved. 
 
 Liebig's Comparative method. A mixture of the substance (which need not be 
 weighed), with the usual proportion of oxide of copper, is introduced into a combustion- 
 tube of such a length as to be half filled by it, the remainder of the tube being filled 
 
 Fig. 30. 
 
 I 
 
 up, half with oxide of copper, half with copper turnings. To the mouth of the 
 combustion-tube is fitted a gas-delivery tube, which passes into a trough of mercury 
 and is made flexible by the insertion of a tube of caoutchouc. 
 
 A screen being placed between the mixture and the pure oxide of copper, the oxide 
 and the metallic copper are first raised to a strong red heat ; a second screen is then 
 placed at the back part of the tube, about an inch from the scaled end, and the portion 
 of mixture at that end is ignited, so that the products of the combustion may drive 
 the atmospheric air out of the tube. The combustion of the rest of the mixture is 
 then carried on in the ordinary way, the heat being gradually extended towards the 
 hinder part of the tube, and the mixture of carbonic acid and nitrogen evolved is 
 collected in a number of graduated jars, half an inch in diameter, and twelve or 
 thirteen inches long. These jars must be accurately divided into equal parts of the 
 same value in all ; but the absolute value of the divisions may be any whatever. 
 
 As soon as one of the tubes is about three-fourths filled with gas, it should be lifted 
 up and the rest of the mercury allowed to run out, so that its place may be supplied 
 
240 
 
 ANALYSIS (ORGANIC) 
 
 with atmospheric air. The object of this is to ascertain whether the gas is free from 
 nitric oxide ; if only y^ pt. of that gas is present, reddish fumes of peroxide of 
 nitrogen will be produced, and if not seen immediately, will become visible on look- 
 ing along the axis of the tube. If any red or yellow colour is perceptible, another jar 
 must be examined in the same manner, and so on till perfectly colourless gas is 
 obtained. When about six jars have been filled with the gaseous mixture, the process 
 may be stopped, nothing being gained by carrying it to the end. 
 
 The jars filled with gas are now to be transferred one by one to a tall jar (fig. 31), 
 containing mercury, and the proportion of carbonic acid and nitro- 
 6 en * n eac k f them determined, by first bringing the mercury to 
 the same level inside and out, and reading off the volume of the 
 gaseous mixture, then absorbing the carbonic acid by a strong 
 solution of caustic potash, introduced by means of the curved 
 pipette A, and reading off the volume of nitrogen left. If the 
 combustion has been properly conducted, the proportion of car- 
 bonic acid and nitrogen should be the same in all the jars. 
 
 Now, a molecule of anhydrous carbonic acid CO 2 , containing 1 atom 
 of carbon [ = 12], occupies the same volume as a molecule (or double 
 atom) of nitrogen, NN [2 . 14 = 28]. If therefore, the volumes of 
 carbonic acid and nitrogen in the gaseous mixture are to one 
 another as m : 1, it follows that the number of carbon-atoms is 
 to the number of nitrogen-atoms as m : 2, and consequently the 
 weight of the carbon in the compound is that of the nitrogen as 
 m x 12 : 2 x 14, or as 3 in : 7 ; so that, if the percentage of 
 carbon (c) be previously found, the percentage of nitrogen (ri) will be 
 given by the equation : _ 
 
 n = - c. 
 3m 
 
 For example, caffeine, which contains 49*48 per cent, of carbon, is 
 found by the process just described to yield carbonic acid and 
 nitrogen in the proportion by volume of 4 : 1 ; the percentage of 
 
 nitrogen in caffeine is therefore . 49'48 = 28'89. 
 
 This comparative method of estimation yields perfectly satisfactory results for all 
 compounds in which the proportion of nitrogen to carbon is not less than 1 : 8, pro- 
 vided the combustion is conducted in such a manner as to avoid the evolution of nitric 
 oxide. The risk of error from this source is less, the more intimately the organic sub- 
 stance is mixed with the oxide of copper, and the more slowly the combustion is per- 
 formed. This rule applies to all combustions of azotised bodies. 
 
 Liebig's comparative method has been variously modified by different chemists. 
 Bunsen has contrived a form of apparatus by which it may be carried out with 
 accuracy, even when the proportion of nitrogen is very small, and with not more 
 than a few centigrammes of substance. This method consists in burning the sub- 
 . stance with oxide of copper and metallic copper in a sealed tube filled 
 ^' ' with hydrogen, and analysing the resulting mixture of carbonic acid and 
 nitrogen in a carefully graduated eudiometer. 
 
 A tube of thick Bohemian glass, about 15 inches long, and of an 
 inch internal diameter, is drawn out at one end in the form of a cone, 
 as shown at a (fig. 32), and the part a is then heated in the blowpipe 
 flame till it is contracted and the glass very much thickened. A mix- 
 ture of 3 to 5 centigrammes of the organic substance, with 5 gnus, of 
 oxide of copper, is now introduced into the tube, together with a few 
 copper turnings, and the other end of the tube is drawn out and thickened 
 in the same manner as the first. The tube is then connected at one end 
 with a hydrogen-apparatus, fig. 33 (A being the generating vessel, and 
 u a receiver containing sulphuric acid to dry the gas), and at the other 
 with an exhausting syringe. The hydrogen, after passing through the 
 tube, escapes by the cock p. 
 
 As soon as all the air is expelled, the cock p is closed, the cork of the 
 generating vessel loosened, the caoutchouc tube c tightly tied, the tube 
 partially exhausted by a stroke of the pump, and the cock s immediately closed. The 
 tube is now sealed at d and b with the blowpipe flame, the sealing being much facilitated 
 bv the partial exhaustion. The next step of the process is to heat the tube to redness. 
 
 having first enclosed it in a mould of gypsum, to prevent it from being blown out by 
 the expansion of the enclosed gases. For this purpose, the two halves of a cylin- 
 drical mould of iron plate, shown in fig. 34, are filled with gypsum paste mixed 
 
ELEMENTARY OR ULTIMATE. 
 
 241 
 
 with a few cow-hairs, and as soon as the plaster begins to set, the tube is laid 
 in one half of the mould, the other half put on, and the two firmly wedged 
 together. The apparatus is then heated to low redness for an hour, the tube taken 
 out when quite cold, and one of the sealed ends broken off under a graduated jar full 
 
 of mercury, so that the mixture of carbonic acid and nitrogen in the tube may pass up 
 to the top of the jar. The gaseous mixture is moistened by passing up a drop of 
 water, then accurately measured, with due regard to corrections for pressure and 
 temperature, and afterwards freed from carbonic acid by thrusting up into it a ball of 
 
 Fig. 34. 
 
 fused potash, fixed at the end of an iron wire (see ANALYSIS OF GASES), the ball being 
 first moistened by breathing on it. This ball is then withdrawn, and another ball of 
 dry potash introduced for the purpose of drying the gas, after which the residual 
 nitrogen is measured. The proportion of carbon and nitrogen is then calculated in the 
 manner already described. 
 
 Other modifications of Liebig's method have been introduced by Dr. Maxwell 
 Simpson (Chem. Soc. Qu. J. vi. 290), by Marchand (J. pr. Chem. xl. 177) and 
 by Gottlieb (Ann. Ch. Pharm. Ixxxviii. 241). 
 
 b. Absolute method. The organic compound is burnt with oxide of copper, as before, 
 and the whole quantity of carbonic acid and nitrogen collected. In the form originally 
 given to this process by Liebig, the carbonic acid and nitrogen wore collected in a 
 graduated jar, containing air and standing over mercury, the gas-delivery tube being 
 bent so as to pass up through the mercury into the air in the jar. The volume of air 
 
 VOL. I. B 
 
242 
 
 ANALYSTS (ORGANIC) 
 
 was carefully noted before the experiment, also the volume of air and gas when the 
 combustion was finished and the apparatus had been left to cool, the observed volumes 
 being in each case reduced to the standard pressure and temperature ; the increase 
 gave the volume of carbonic acid and nitrogen produced by the combustion. The 
 volume of carbonic acid was then calculated from a previous determination of the 
 carbon, and this, deducted from the volume of the mixed gases, gave the quantity of 
 nitrogen by volume, from which the weight was calculated. For example, O'l grin, 
 caffeine burnt in this manner yields lli'06 cub. cent, of gas at C. and 28" bar. 
 The same quantity burnt in the ordinary way yields 0'181 grm. carbonic acid, cor- 
 responding to 91*09 cub. cent, at C. and 28 inches of the barometer : consequently O'l 
 grm. caffeine yields 114-06 91'09 = 22'85 cub. cent, nitrogen gas = 28*86 per cent, by 
 weight. 
 
 The process in this form is liable to numerous sources of error. In the first place, 
 the necessary limits to the the size of gas jars standing over mercury, restricts the 
 quantity of substance burnt to 1 or 2 decigrammes ; and with this small qxiantity the 
 errors of observation and manipulation bear too great a proportion to the whole to give 
 even a good approximation to the truth, unless the proportion of nitrogen is rather 
 large. Very considerable errors may arise from the alteration in the dimensions of 
 the tube, likely to result from softening by heat, and from the consumption of a 
 portion of the oxygen of the air in the tube during the combustion. (For the details 
 of the process, see Handworterbuch d. Chemie, 2 te Aufl. i. 873.) 
 
 To remove these sources of error, the process has been modified by Dumas and 
 others, so as to make the result independent of the volume of air in the apparatus. 
 This is effected by replacing the air by another gas, which can afterwards be removed 
 by absorption, and sometimes also by exhausting with the air-pump. 
 
 In Dumas' s process, the air is removed from the combustion-tube, partly by ex- 
 haustion with the air-pump, and partly by a stream of carbonic acid gas evolved from 
 carbonate of copper placed at the sealed end of the tube. The combustion is then 
 performed ; the carbonic acid and nitrogen evolved by it are collected in a graduated 
 jar standing over mercury, and containing also solution of potash, which absorbs the 
 carbonic acid; and, when the combustion is finished, the carbonate of copper is again 
 heated, so as to evolve carbonic acid, and sweep all the remaining nitrogen into the 
 jar. The volume of nitrogen is then observed, with due regard to pressure and 
 temperature. 
 
 This process gives accurate results ; but it is troublesome, and requires rather 
 complicated apparatus. A simpler form of it is now generally used, -in which the 
 exhaustion with the air-pump is dispensed with by the use of a substance which 
 evolves carbonic acid more abundantly than carbonate of copper. This simplification 
 is due to Mel sens. (Ann. Ch. Pharm. Ix. 115.) 
 
 At the sealed end of a combustion-tube 30 inches long, is placed a layer, 6 inches long, 
 of acid carbonate of sodium, a b (jig. 35) ; then oxide of copper, be; then the mixture 
 
 of the organic substance with oxide 
 of copper, cd; then strongly ig- 
 nited oxide of copper, dc; and, 
 lastly, copper turnings, ef. The 
 tube is enveloped in copper foil or 
 brass wire gauze, and connected by 
 a gas delivery- tube with a graduated 
 
 jar, standing over mercury (fig. 36), and partly filled with strong solution of potash. 
 The tube is laid in the combustion furnace, and the acid carbonate of sodium gradually 
 
 heated, the other part of the 
 
 Fig. 36. tube being protected by a 
 
 screen. Carbonic acid gas 
 is then evolved, and drives 
 the air out of the tube. It 
 is tested from time to time 
 by collecting it in small 
 tubes filled with mercury, 
 and passing caustic potash 
 into it. As soon as the 
 gas is completely absorbed 
 by the potash-ley, showing 
 that all the air is expelled 
 from the tube, the heat is removed from the acid carbonate of sodium ; the graduated 
 jar, filled partly with mercury, and partly with potash-ley, is adjusted in its place 
 over the extremity of the delivery-tube, and the combustion is commenced. The 
 nitrogen and carbonic acid then pass over together; the carbonic acid is absorbed 
 
ELEMENTARY OR ULTIMATE. 243 
 
 by the potash ; and the nitrogen collects in the jar. When the combustion is finished, 
 heat is again applied to the acidcarbonate of sodium, so as to evolve more carbonic acid, 
 and sweep all the residual nitrogen into the gas jar. 
 
 The gas is left standing over the caustic potash till the absorption of the carbonic 
 acid appears to be quite complete : it may be accelerated by a gentle agitation. A 
 ground glass plate is then placed under the jar, pressed against it, to prevent the mer- 
 cury from running out, and the jar is transferred from the mercury-trough to a large 
 vessel of water. On removing the glass plate, the mercury and potash-ley run out, 
 their place being supplied by water. The volume of the gas is then read off, and 
 reduced to the standard pressure and temperature, allowance being also made for the 
 tension of the aqueous vapour. From the corrected volume of nitrogen thus obtained, 
 the weight is easily deduced by calculation. 
 
 If commercial bicarbonate of soda is used in this process, it must be tested 
 beforehand, in order to ascertain whether it gives off any gas not absorbable by 
 potash. Indeed, it is advisable to subject all the materials used in the process to a 
 trial by ignition without the organic substance. They ought not to yield more than to 
 1| c. c. of gas not absorbed by potash-ley. 
 
 It is also of the greatest importance, in all nitrogen estimations in which the 
 nitrogen is determined by volume, to test carefully the accuracy of the weights with 
 which the substance to be analysed is weighed out. In other analyses, the absolute 
 value of the weights used is unimportant, provided they agree amongst themselves ; 
 but if the gramme weight and its subdivisions, with which the substance is weighed 
 out, are not true to their standard values, the weight of the nitrogen, determined by 
 calculation from its observed volume, according to fixed data, will not give the true 
 weight of nitrogen contained in the compound. 
 
 Another modification of Dumas's process is given by Dr. Maxwell Simpson 
 (Chem. Soc. Qu. J. vi. 299). The combustion is made with a mixture of oxide of 
 copper and mercuric oxide, the free oxygen evolved by the latter being absorbed by 
 red-hot copper, and the atmospheric air expelled by a stream of carbonic acid, evolved 
 from carbonate of manganese. The gaseous mixture evolved by the combustion is 
 collected in a receiver of peculiar construction, from which, after the carbonic acid has 
 been absorbed by potash, the nitrogen can be transferred, without loss, to a eudio- 
 meter, and accurately measured over mercury. The details are as follows : 
 
 A combustion-tube, from 1\ to 3 feet long, is sealed at one end, and a mixture of 
 12 grm. carbonate of manganese and 2 grm. mercuric oxide (the latter being added to 
 prevent the possible formation of carbonic oxide) is introduced into it. At an inch 
 from this mixture is placed a plug of asbestos, and then the mixture of the substance 
 to be analysed (5 or 6 decigm.) with about 45 times its weight of a mixture of 4 pts. 
 oxide of copper and 5 pts. oxide of mercury. To ensure that the oxide of mer- 
 cury is free from nitrogen, it must be prepared, not by ignition of the nitrate, but by 
 precipitating corrosive sublimate with excess of caustic potash ; the precipitate is 
 washed with aqueous phosphoric acid, to remove free potash, then with water, and 
 dried at a rather strong heat. 
 
 The mixture having been introduced, the mortar is rinsed out with oxide of copper, 
 and the rinsings added as usual ; then a plug of asbestos is thrust in ; then 2 or 3 
 inches of pure oxide of copper added, this also being kept in its place by an asbestos 
 plug; and the tube is filled up with metallic copper, prepared by 
 reducing the coarse-grained oxide (p. 226) with hydrogen. The open Fig. 37. 
 end of the tube is then drawn out, and the neck joined by a 
 caoutchouc connector with a gas delivery-tube, bent at right angles 
 and dipping into the mercury-trough. 
 
 The combustion-tube is now laid in the furnace, and heat is applied 
 to the metallic copper and oxide of copper, and at the same time to 
 the carbonate of manganese, the heated portions being shut off by 
 screens from the middle of the tube ; and as soon as the air is com- 
 pletely expelled from the tube by the stream of carbonic acid, the 
 mixture of the oi-ganic substance with the oxides is heated in the 
 usual way, from the front backwards, the tube being first connected 
 with the vessel intended to receive the nitrogen. This vessel lias the 
 form shown injiy. 37, and a capacity of about 200 cub. cent. : the ex- 
 ternal diameter of the upper part should not exceed 7 or 8 mm. 
 A tube of thick vulcanised caoutchouc, 1| inch long, is slipped over 
 the top, which it must accurately fit, to the extent of half an inch, and securely 
 bound round with silk cord. A glass rod, half an inch long, with the ends ground 
 flat, and having the same diameter as the caoutchouc tube, is thrust down the latter 
 till it touches the gas vessel. A piece of thermometer tubing, also of the same dia- 
 meter, and having a fine hair-bore, is bent into the form shown in fig, 38, and also 
 
 & 2 
 
244 
 
 ANALYSIS (ORGANIC) 
 
 Fig. 38. 
 
 inserted. The caoutchouc is next slightly stretched over it, and firmly secured with 
 silk cord, so that there may be no interval between the glass rod, bent tube, and gas 
 vessel. A silk cord is, lastly, tied round the part of the caoutchouc tube where the 
 solid rod lies, so as to make it perfectly air-tight. Before using the apparatus, the 
 joints must be tested by partially filling it with mercury, plunging the mouth 
 beneath the surface of the liquid, and observing if the level remains constant. 
 
 The apparatus is completely filled with mercury and caustic potash solution, and 
 placed in the mercurial trough as shown in fig. 38. The gas delivery-tube, proceeding 
 
 from the combustion- 
 tube, being then in- 
 serted into its lateral 
 opening, the products 
 of combustion pass into 
 it, the carbonic acid 
 being absorbed by the 
 potash-ley, while the 
 nitrogen remains. At 
 the termination of the 
 combustion, the nitro- 
 gen still remaining in 
 the tube is swept out 
 into the receiver by a 
 stream of carbonic acid, 
 evolved by heating the 
 portion of carbonate of 
 manganese still remain- 
 ing undocomposed. 
 
 The next thing to be done is to transfer the nitrogen to a eudiometric tube. For 
 this purpose a bent tube, narrowed towards the lower part of the upright arm is fitted 
 air tight to the lateral opening of the receiver by means of a cork, care being taken 
 that no air is introduced in fitting it, to ensure which it is best to moisten the cork 
 with a solution of corrosive sublimate. Mercury is now poured into the bent tube, 
 and the receiver is lifted out of the mercury, carried to a mercurial trough with glass 
 sides (fig. 39), and allowed to stand for an hour or two, so that the absorption of the 
 
 carbonic acid may be com- 
 
 Fig. 39. plete. A eudiometer, pre- 
 
 viously moistened with a drop 
 of water, so that the gas may 
 be saturated with moisture, 
 is then carefully filled with 
 mercury, and inverted in the 
 trough ; the end of the gas 
 delivery-tube from the re- 
 ceiver is brought under it; 
 the cord which tied the 
 caoutchouc tube to the glass 
 rod is removed ; and the ni- 
 trogen is driven into the 
 eudiometer by slowly pouring 
 mercury into the bent tube, 
 as shown in the figure. As 
 soon as the potash-ley makes 
 its appearance in the gas de- 
 livery-tube, the addition of 
 mercury is stopped. The 
 volume of nitrogen which 
 
 then remains in the gas delivery tube is exactly equal to the volume of the air which 
 was contained in it at the beginning of the process, and was driven into the eudiometer 
 tube by the first portions of mercury added, so that the volume of gas driven into the 
 endiometer is exactly that which was contained in the receiver. Lastly, the gas is 
 measured, with due regard to pressure and temperature, and the weight calculated 
 accordingly. 
 
 This process gives very exact results. Its peculiar advantages are, that the free 
 oxygen evolved from the oxide of mercury ensures complete combustion, while the 
 vapour of mercury prevents the formation of any oxides of nitrogen : moreover, it 
 enables the gas to be measured over mercury, which is much more exact than the 
 ordinary mode of measuring over water. - 
 
ELEMENTARY OR ULTIMATE. 245 
 
 Estimation of Nitrogen by Witt and Varrcntrapp' s Method. Most azotised organic 
 bodies heated with hydrate of potassium or sodium, give off the whole of their nitrogen 
 in the form of ammonia, the carbon uniting with the oxygen of the alkaline hydrate to 
 form carbonic acid, while the hydrogen combines with the nitrogen to form ammonia. If 
 the quantity of nitrogen present is not sufficient to unite in this manner with all the 
 hydrogen, the remainder is evolved as gas ; but there is no organic substance, ex- 
 cepting those containing nitric acid, in which the quantity of nitrogen is too great to be 
 completely converted into ammonia by the hydrogen thus liberated from the alkaline 
 hydrate. In many cases, however, cyanide of potassium or sodium is formed in the 
 first instance ; but even then, if a sufficient excess of the alkaline hydrate is present, 
 the cyanogen is decomposed when the heat becomes very strong, and the whole of the 
 nitrogen is given off as ammonia. It is on these facts that Will and Varrentrapp's 
 method of estimating nitrogen is founded. 
 
 As the hydrates of potassium and sodium are very deliquescent, and act strongly on 
 glass at high temperatures, it is convenient to mix them with quick lime, which makes 
 them more manageable, and diminishes their action on the glass. The mixture 
 generally used is soda-lime, containing 1 pt. of hydrate of sodium, and 2 pts. of quick 
 lime. It is prepared by adding the requisite quantity of quick lime to caustic soda-ley 
 of known strength, evaporating to dryness in an iron pot, calcining the residue in a 
 crucible, and afterwards rubbing it to fine powder in a warm mortar. It must be 
 preserved in wide-mouthed vessels with good stoppers. If commercial soda is used 
 for this purpose, it must be previously tested for nitric acid, as the presence of that 
 compound would vitiate the analysis. 
 
 The substance to be analysed is mixed in a warm porcelain mortar, with a quantity 
 of soda-lime sufficient to fill about two-thirds of a combustion-tube, from 16 to 
 18 inches long. The soda-lime must be previously heated over a lamp to expel any 
 moisture or ammonia that it may have absorbed, and the mixture must be made by 
 very gentle trituration, otherwise portions of it will adhere obstinately to the mortar 
 and pestle. After it has been introduced into the tube, the mortar is rinsed with 
 fresh soda-lime, and finally with pounded glass, to remove any small portions of ad- 
 hering matter. Lastly, the tube is filled up with soda-lime to within an inch of the 
 extremity, a plug of ignited asbestos being placed at the end to prevent the light 
 powder from being carried forward by the vapours. 
 
 The ammonia is collected in a bulb-apparatus of the form shown in fig. 40, con- 
 
 Fig. 40. 
 
 taining hydrochloric acid (specific gravity about 1*10), sufficient to half fill one of the 
 larger bulbs. This apparatus is adapted to the combustion-tube in the manner shown 
 in the figure, and the tube is gradually heated from end to end. Ammonia is then given 
 off and is absorbed by the hydrochloric acid. Towards the end of the combustion, the 
 heat must be very much increased, in order to decompose any cyanide of sodium that 
 may have formed in the earlier stage of the process. When the combustion is finished, 
 the point of the tube is broken off, and air drawn through the apparatus in the usual way. 
 Bouis (Bullet. Soc. Chim. de Paris, i. 105) recommends to place at the closed end of 
 the tube a mixture of oxalate of calcium and slaked lime (obtained by neutralising 
 oxalic acid with milk of lime, boiling the precipitate with excess of lime, and drying 
 rapidly at 110 C.) which, when decomposed at the end of the operation, evolves a 
 stream of hydrogen that sweeps all the ammonia remaining in the combustion-tube into 
 the acid placed to receive it. 
 
 The acid liquid is emptied into a capsule, and the bulbs are rinsed with alcohol, 
 and then repeatedly with distilled water. Sometimes oily hydrocarbons are formed 
 during the combustion, and collect on the surface of the acid liquid. In this case it 
 is best, before proceeding further, to separate the oil from the acid liquid bv filtration, 
 the filter being previously moistened with water. Bichloride of platinum is*now added 
 to the acid solution, which precipitates the ammonia as chloroplatinate of ammonium, 
 NH'Cl . PtCP ; the whole is evaporated to dryness over the water-bath ; and the dry 
 mass when cold, is treated with a mixture of 2 volumes of strong alcohol and 1 vol. 
 
 it 3 
 
246 ANALYSIS (ORGANIC) 
 
 ether, which dissolves the excess of bichloride of platinum, and leaves the chloro- 
 platinate of ammonium. This suit is collected on a weighed filter, washed with the 
 same mixture of alcohol and ether, then dried at 100 and weighed ; 100 pts. of it 
 correspond to 6*279 pts. of nitrogen. Or, the salt with its filter may be ignited in a 
 weighed crucible of platinum or porcelain, till the filter is completely burned to ashes 
 and metallic platinum is left. The ignition must be performed with great care, 
 commencing with a very gentle heat, which should be increased very gradually, 
 because the vapours of sal-ammoniac and chlorine which escape are very apt to carry 
 with them a small quantity of platinum : 100 pts. of platinum correspond to 14-204: 
 pts. of nitrogen. 
 
 The process just described may be applied to most azotised organic bodies without 
 further modification. Sometimes, however, when the proportion of nitrogen is large, 
 as in urea, mellone, &c., the whole of the hydrogen is given off as ammonia. In this 
 case, the quantity of uncondensable gas evolved is comparatively small, and towards 
 the end of the process, the acid in the bulbs is very likely to be suddenly drawn back 
 into the combustion-tube. This accident may be prevented by adding to the mixture 
 a small quantity of sugar or tartaric acid, so as to dilute the ammonia with uncon- 
 densable gases. 
 
 Liquids containing nitrogen may be treated in the same manner, being enclosed in 
 bulbs, as for combustion with oxide of copper. 
 
 There are some azotised organic bodies to which Will and Varrentrapp's process is 
 not applicable, those, namely, in which the nitrogen exists in the form of an oxide, 
 generally as NO 2 (the so-called nitro-compounds) : these bodies, when ignited with 
 an alkaline hydrate, giving off only a portion of their nitrogen in the form of ammonia, 
 so that the quantity found is always too small. 
 
 Other azotised bodies, when heated with soda-lime, give off, not ammonia, but organic 
 bases free from oxygen, and more or less resembling ammonia. Thus indigo yields 
 phenylamine (C 6 !FN), and many non-volatile organic bases, e.g, narcotine, morphine, 
 quinine, and cinchonine, give off organic volatile bases. Many non-oxygenised 
 organic bases, such as phenylamine, chinoline, &c., pass over ignited soda-lime without 
 decomposition, or at all events do not yield all their nitrogen in the form of ammonia. 
 Now all these volatile organic bases form platinum-salts, in which, as in chloro- 
 platinate of ammonium, 1 atom of platinum corresponds to 1 atom of nitrogen. If, 
 therefore, these bases are treated by Will and Varrentrapp's process, the resulting 
 platinum-salts ignited, and the metallic platinum weighed, 100 pts. of it will correspond 
 to 14 204 pts. of nitrogen, whatever organic base may have been formed in the decom- 
 position. As, however, the platinum-salts of many of these bases are more soluble in 
 alcohol than chloroplatinate of ammonium, it is best to wash them, not with the 
 mixture of alcohol and ether above-mentioned, but with absolute ether to which only a 
 few drops of alcohol are added. In all cases in which it is not certainly known that the 
 body submitted to analysis gives off the whole of its nitrogen as ammonia, the chloro- 
 platinate should be ignited after being weighed, and the residual platinum weighed 
 again, so as to ascertain whether the chloroplatinate weighed was really chloroplatinate 
 of ammonium. (NIFPtCl 3 corresponds to 44*3 per cent, platinum.) 
 
 Instead of precipitating the ammonia with bichloride of platinum, its quantity may 
 also be determined volumetrically, for instance, by receiving it in dilute sulphuric acid 
 of known strength, and estimating the quantity of free acid remaining by means of a 
 standard alkaline solution. Peligot uses for this purpose dilute sulphuric acid, containing 
 61-25 grms. of SO 1 !! 2 , in a litre of liquid; neutralises it with a measured quantity of 
 a solution of lime in sugar-water ; and compares the quantity of the lime-solution re- 
 quired for this purpose with that which is required to neutralise the same volume of 
 acid after absorption of the ammonia. Instead of the solution of lime in sugar-water, 
 which quickly varies in strength, and must be standardised before each experiment, it 
 is better to use a standard : olution of caustic soda (see ACIDIMETRY, and ANALYSIS 
 You METRIC). If an acid be used containing 1 at. S0 4 H 2 in a litre of liquid, and a 
 solution of soda containing 2 at. NallO in the same volume of liquid, the quantity of 
 acid saturated by the ammonia will be very readily found, and thence also the quantity 
 of ammonia absorbed. These methods, being more rapidly executed than the platinum- 
 determination, are especially applicable in the determination of nitrogen for technical 
 purposes, in the valuation of guano for example. 
 
 Other modifications of Will and Varrentrapp's process have been proposed, for 
 example, receiving the ammonia in tartaric acid, but they do not appear to present 
 any peculiar advantages. 
 
 ESTIMATION OF CHLORINE. 
 
 Organic bases combine with hydrochloric acid, forming salts (the hydrochlorate of 
 iiioi-piiiiie, for example), from the solutions of which chlorine may be completely prcci- 
 
ELEMENTARY OR ULTIMATE. 247 
 
 pitated by simply adding nitrate of silver. But many organic compounds contain 
 chlorine in a form in which it cannot be precipitated as chloride of silver, until the 
 compound is completely destroyed. 
 
 The mode of decomposition adopted in such cases is to ignite the compound with a 
 caustic alkali or alkaline earth, generally with quick lime. The lime used for the 
 purpose is obtained by subjecting marble to a strong red heat in a crucible. It must 
 be tested for chlorine, and if that element is found in it, the lime must be slaked, and 
 the chloride of calcium separated from it by washing with water, after which it is to 
 be recalcined. 
 
 The organic compound, if solid, is mixed in a mortar with the pure pounded lime, 
 the mixture introduced into a combustion-tube from 12 to 18 inches long, and the 
 tube filled-up with pure lime, or (in order to diminish the quantity of lime which has 
 to be subsequently dissolved in nitric acid) with a mixture of lime and pounded glass. 
 The mixture is then burnt in the usual manner ; afterwards, while the tube is still 
 hot, the open end is closed by a cork, it is then wiped with a piece of filter-paper, and 
 gradually introduced into a tall glass cylinder about one-third full of cold distilled 
 water : the hot tube breaks on thus coming in contact with the water, and its contents 
 fall into the cylinder, where the excess of lime is dissolved by nitric acid. The liquid 
 is then filtered, if necessary, and the chlorine precipitated by nitrate of silver. Or, 
 the contents of the tube when cold are turned out into a jar of distilled water, and the 
 whole is dissolved by nitric acid. This method, however, is more subject to error than 
 the first ; for it is difficult to prevent a portion of the very fine dust of lime being 
 carried away by the air while emptying the tube into the water. 
 
 Liquids containing chlorine are enclosed in bulbs in the manner already described 
 (p. 232), and the vapours passed over the red-hot lime. 
 
 Bromine and iodine in organic compounds are estimated in like manner. 
 
 ESTIMATION OF SULPHUR. 
 
 Sulphur is sometimes contained in organic compounds in such a manner that it 
 exhibits its usual reactions with metallic solutions ; more generally, however, its sepa- 
 ration can only be effected by the complete destruction of the compound. In some 
 cases, oxidation with strong nitric acid will effect the decomposition, the sulphur being 
 converted into sulphuric acid ; but a more certain method is to fuse the compound 
 with an alkaline hydrate or carbonate, mixed with nitre, chlorate of potassium, or oxide 
 of mercury. 
 
 For non- volatile bodies, a few lumps of hydrate of potassium are fused in a silver 
 crucible over a gas lamp, with about i of nitre, a few drops of water being added to 
 facilitate the fusion ; a weighed quantity of the sulphuretted organic compound is then 
 added in successive small portions, and the heat is gradually raised, small quantities 
 of nitre being thrown in from time to time, if necessary, to burn away the carbon. 
 The fused mass when cold is dissolved in boiling water, the excess of alkali neutralised 
 with hydrochloric acid, chloride of barium then added, and the precipitate of sulphate 
 of barium filtered, washed, and ignited with the usual precautions. (See SULPHURIC 
 ACTD.) 
 
 Sulphur-compounds may also, whether fixed or volatile, be burnt in a combustion- 
 tube with a mixture of carbonate of sodium, with nitre, chlorate of potassium (Kolbe), 
 or oxide of mercury (Russell, Chem. Soc. Q,u. J. vii. 212), non-volatile pulverisable 
 .solids being mixed up with the carbonate of sodium and the oxidising agent, volatile 
 liquids being enclosed in sealed bulbs, and volatile solids and fatty bodies placed in 
 platinum boats. 
 
 ESTIMATION OF PHOSPHORUS. 
 
 Phosphorus in organic bodies is estimated by burning the substance with a mixture 
 of alkaline carbonate and nitre or chlorate of potassium, in the same manner as for 
 sulphur, and precipitating the resulting phosphoric acid as phosphate of magnesium 
 and ammonium. Similarly for arsenic. 
 
 Other non-volatile substances occurring in organic compounds are estimated by the 
 ordinary processes adapted to each of them, in the residue left after the organic matter 
 has been burnt away. 
 
 An easier method of estimating sulphur, phosphorus, chlorine, &c., in organic com- 
 pounds, lately introduced by Carius (Ann. Ch. Pharm. cxvi. 1), consists in heating 
 the substance with nitric acid, of specific gravity about 1-2, in a sealed tube. 
 Sulphur is thereby, in nearly all cases, completely converted into sulphuric acid,, and 
 may be precipitated by chloride of barium ; phosphorus and arsenic are converted into 
 phosphoric and arsenic acids, and may be precipitated as ammonio-magnesium salts ; 
 chlorine is partly oxidised, partly separated in the free state, but may be completely 
 
 it 4 
 
248 ANALYSIS (ORGANIC) PROXIMATE. 
 
 converted into hydrochloric acid by means of a dilute solution of sulphurous acid or 
 sulphite of sodium, and then precipitated by nitrate of silver; bromine and iodine are 
 completely separated in the free state, and may be estimated in like manner ; lastly, 
 metals are converted into oxides or nitrates, and may be estimated by the ordinary 
 methods of mineral analysis. 
 
 This method of oxidation by nitric acid in sealed tubes, is likewise applicable to 
 many inorganic compounds, the sulphides of arsenic, for example. (For details, see the 
 articles CHLORINE, PHOSPHORUS, SULPHUR, &c.) 
 
 DETERMINATION OF THE CHEMICAL FORMULA OF AN ORGANIC COMPOUND. 
 
 When the quantities of the several elements of a compound which make up a given 
 weight, say 100 parts, are known, it is easy to calculate the relative number of atoms 
 of these elements. For, since the actual weight of a substance ( W) is equal to the 
 weight of each atom (A), multiplied by the number (n) of the atoms (W = n A), it 
 follows that the number of atoms is equal to the total weight divided by the atomic 
 
 weight (n = ) ; so that, when the percentage composition is known, the relative 
 
 ri& 
 
 numbers of the atoms in other words, the empirical formula will be found by dividing 
 the percentage of each element by its atomic weight, and reducing the result to its 
 simplest numerical expression. 
 
 For example, sorbic acid is found by Hofmann's analysis (Chem. Soc. Qu. J. xii. 46) 
 to contain in 100 parts : 64-38 C, 7'20 H, and 28-42 0. Therefore: 
 
 Number of Carbon-atoms = = 5-36 or 3 
 
 7'20 
 Hydrogen-atoms = = = 7'20 or 4 
 
 23.42 
 Oxygen-atoms = = 1-77 or 1 
 
 consequently, the simplest atomic expression of the constitution of sorbic acid is 
 C 3 H<0. 
 
 Whether this is the real expression for the composition of the molecule, or whether 
 it should be C 6 H 8 2 , or C 3 H 12 3 , or any other multiple of the first formula, must be 
 determined by other considerations. In the case of an acid, we naturally look to the 
 constitution of its salts, the barium- and silver-salts being generally selected as being 
 the most easily prepared and analysed. The analysis of sorbate of barium gives : 
 
 InlOOpts. at. wt. No. of atoms. 
 
 Carbon . . . 40-37 -^ 12 3'36 or 6-08 
 
 Hydrogen . . . 4-02 -7- 1 = 4-02 or 7 '27 
 
 Barium . . . 7'89 4- 68'5 = 0*55 or 1 
 
 Oxygen . . . 17'72 *- 16 = I'll or 2 
 
 100-00 
 
 This approaches very nearly to the formula C 6 H 7 Ba0 2 , showing that the rational 
 formula of sorbic acid is, not C 3 H 4 0, but C 6 H 8 2 , supposing the acid to be monobasic, or 
 C 12 H 1B 4 , if it is dibasic. Which of these hypotheses is correct must be determined 
 by other considerations ( ACIDS, p. 46). The monobasic formula is adopted because it 
 is found that sorbic acid forms but one class of salts, one ether, one amide, &c. 
 
 The rational formulae of bases are also determined by the constitution of their salts. 
 The platinum-salts are most generally relied on, because they can be easily obtained 
 pure, and the platinum can in most cases be determined with great accuracy. The 
 rational formula of the base is that which corresponds to 1 atom of platinum. Thus 
 the platinum-salt of nitranisidine gives numbers corresponding to the formula, 
 C 7 H 8 N 2 O 3 .HCl,PtCl 2 : hence the formula of the base is C 7 H 8 N O 3 . In some cases, the 
 gold-salts are better adapted than the platinum-salts for determining the constitution 
 of an organic base. But any well defined and stable salt in which the amount of acid 
 or acid-radicle can be directly and accurately determined, will answer the purpose 
 equally well. 
 
 To determine the rational formula of a compound which is neither acid nor basic, 
 recourse must be had to its derivation and to its modes of decomposition. Thus 
 indigo yields by analysis numbers corresponding to the fornmla, C 8 H 5 NO. By 
 oxidising it with nitric acid, we obtain isatin, C 8 H 5 N0 2 (=indigo + O) ; and isatin 
 treated with potash yields the potassium-salt of isatic acid, C 8 H 3 KN0 3 . Now, as 
 isatic acid exhibits the characters of a monobasic acid, this formula shows that it con- 
 
ANALYSIS (ORGANIC) PROXIMATE. 
 
 tains 8 atoms of carbon ; and consequently isatin and indigo, which are related to it in 
 the manner just mentioned, must also contain 8 atoms carbon. Substitution-producl s 
 formed under the influence of chlorine, nitric acid, &c. are often of great use in deter- 
 mining rational formulae. Thus the composition of mesitylol may be expressed em- 
 pirically by either of the formulse, C 3 H 4 , C 6 H 8 or C'H' 2 . But this body, under tha 
 influence of nitric acid, yields the three substitution-products, nitro mesitylol, 
 C 9 H"(N0 2 ), dinitromesitylol, C 9 H'(N0 2 ) 2 , and trinitromesitylol, C 9 H 9 (N0 2 ) 3 , the corn- 
 position of which is utterly irreconcilable with the formula, C 3 II 4 , or C G H 8 . Again, 
 the composition of naphthalin might be expressed empirically by the formula, C 10 H 8 , or 
 C 5 II 4 ; but the existence of the compounds, C'H 7 C1, C 10 H f Cl 2 , C 10 H''CP, C">H 5 BrCl 2 , 
 C 10 H 4 BrCl 3 , and C 10 H 3 Br 2 Cl 3 , shows clearly that the higher formula is the true one. 
 
 When a compound is volatile without decomposition, its atomic weight may gene- 
 rally be determined by means of its vapour-density. In nearly all cases, the mole- 
 cule of a compound in the gaseous state is sxipposed to occupy 2 volumes (ATOMIC 
 VOLUME), in other words, the vapour-density is half the weight of the molecule, and 
 the formula of the compound must be calculated accordingly. Thus the vapour- 
 density of alcohol, as determined by Gray-Lussac, is T6133, referred to air as unity, or 
 
 23*25, referred to hydrogen as unity. The double of this number, or 46-5 
 
 is therefore the weight of the molecule. Now the composition of alcohol, as deter- 
 mined by elementary analysis, is C 2 H 6 0, and the weight of the molecule calculated 
 from this formula is 46. The formula of alcohol is therefore C 2 H 6 and not any mul- 
 tiple thereof. 
 
 II. PROXIMATE OBGANIC ANALYSIS. 
 
 The knowledge of the ultimate elements of which an organic body is composed, is 
 not sufficient to give a complete idea of its constitution, unless the substance under 
 examination is a definite chemical compound, such as sugar, alcohol, albumin, &c. In 
 that case, all the knowledge that we wish to obtain, or indeed that we can obtain re- 
 garding the constitution of the body, is derived from its elementary analysis, together 
 with the study of its chemical reactions ; but when a complex organ, as a leaf or a 
 root, or a vegetable or animal fluid, such as the sap, milk or blood, is to be examined, it 
 is necessary, before proceeding to the ultimate analysis, to separate the several definite 
 compounds o? proximate elements, of which the complex substance is made up; just as 
 in examining a sample of granite, it is not sufficient to know the relative quantities 
 of silicon, aluminium, potassium, oxygen, &c., which it contains, but we require 
 also to know something of the manner in which these elements are grouped in the 
 form of definite minerals ; in other words, to ascertain what proportions of quartz, 
 felspar, and mica enter into the composition of the rock. 
 
 The ultimate analysis of organic bodies is, as we have seen, reduced to a very com- 
 plete system ; there is indeed no element occurring in an organic compound which 
 cannot be detected with certainty, and estimated quantitatively within very narrow 
 limits. But it is otherwise with the proximate analysis. With regard to vegetable 
 substances in particular, nothing more than a few general directions can be given. In 
 the case of animal bodies, some progress has been made towards the establishment of 
 a systematic course of qualitative analysis, but much remains to be done before the 
 method can approach in regularity and exactness to the processes of mineral analysis. 
 
 The substance, whether vegetable or animal, solid or liquid, is divided into two parts, 
 one for the determination of the inorganic, the other for that of the organic consti- 
 tuents. The former is dried and incinerated (see ASHES) and the ash examined by 
 the processes of mineral analysis. The former, if the analysis is to be quantitative, 
 and in some instances also for qualitative analysis, is dried at a temperature between 
 100 and 110 or 115 C., great care being taken not to let the heat rise too high, as 
 organic bodies are very easily decomposed by heat. Some bodies must be dried at 
 the ordinary temperature over sulphuric acid. Liquids are first evaporated in 
 shallow basins over the water-bath, and the residue is then dried at a somewhat 
 higher temperature. 
 
 The dried residue or the original substance, is then subjected to the action of 
 various solvents, generally of ether, alcohol and water. Gerhardt recommends these 
 solvents to be used in the order here indicated : this of course implies that the sub- 
 stance is previously dried. Ether dissolves especially fatty and waxy substances, 
 resins and camphors; alcohol dissolves the same substances with less facility, 
 but on the other hand, it dissolves many substances which are insoluble in ether: 
 water dissolves saccharine, gummy and amylaceous substances, and salts of organic 
 acids. Benzol, oil of turpentine, chloroform and sulphide of carbon, are also 
 used as solvents. Vegetable alkalis are extracted by dilute sulphuric or hydro- 
 
250 ANALYSIS (ORGANIC) PROXIMATE. 
 
 chloric acid ; organic acids by dilute ammonia or potash. The solutions of vegetable 
 acids, and of certain other substances thus obtained, are often treated with acetate or 
 subacetate of lead, in order to precipitate the organic principles in the form of in- 
 soluble lead-salts, which are then decomposed by sulphuretted hydrogen. Acetate of 
 aluminium and ferric acetate are also used as precipitants. 
 
 The solutions obtained in this -way generally contain a mixture of proximate organic 
 principles, which must be separated by fractional distillation, precipitation, saturation, 
 or crystallisation : when crystals are obtained, it is mostly of great service to examine 
 them by the microscope, in order to determine their form, and ascertain whether they 
 are homogeneous. 
 
 Fractional precipitation with acetate of lead is much used for the separation, of the 
 higher terms of the fatty acid series, stearic, palmitic, acid, &c. The mixture of fatty 
 acids is dissolved in alcohol ; the solution is partially precipitated with acetate of 
 lead ; the precipitate is decomposed by sulphuric acid ; the fatty acids thereby sepa- 
 rated are redissolved in alcohol, and again partially precipitated ; and this series of 
 operations is repeated till the fatty acid thus separated shows a constant melting 
 point. 
 
 The method of fractional saturation applied by Liebig to the separation of some of 
 the lower terms of the fatty acid series, may also here be noticed. When valeric and 
 butyric acids occur together in a liquid, their separation may be effected by half 
 saturating the mixture with soda, and distilling. If the valeric acid is in excess, pure 
 valerate of sodium is left behind, and a mixture of butyric and valeric acids distils 
 over ; if, on the contrary, the butyric acid is in excess, the residue contains butyrate as 
 well as valerate of sodium : but the distillate consists of pure butyric acid. On dis- 
 tilling the residue with excess of dilute sulphuric acid, the two acids pass over together, 
 and by partially neutralising the distillate with an alkali, and again distilling, a fur- 
 ther separation may be effected. At each stage of the process, the less volatile acid 
 (the valeric) displaces the more volatile, and one only of the acids is found either in 
 the distillate or in the residue, according as the more or the less volatile acid predo- 
 minates. When a mixture of acetic acid with butyric or valeric acid is treated in this 
 manner, different phenomena present themselves, the acetic acid, though the most 
 volatile, exhibiting the greater tendency to displace the other two and remain in the 
 residue. This peculiar behaviour is due to the formation of an acid acetate of sodium, 
 C 2 H 3 Na0 2 .C-H'0 2 , which is not decomposed by either of the other acids. Hence, 
 if the mixture contains more acetic acid than is sufficient to form an acid acetate with 
 the quantity of soda added, the excess will pass over together with the whole of the 
 butyric or valeric acid present, the residue consisting of pure acid acetate of sodium ; 
 if, on the contrary, the quantity of acetic acid is less than sufficient to convert the 
 whole of the soda into the acid acetate, pure valeric or butyric acid will pass over, and 
 the residue will contain acid acetate of sodium, mixed with butyrate or valerate. 
 
 Volatile oils are separated by fractional distillation. The roots, seeds, leaves, &c., 
 containing them are macerated in water and distilled, and the oils which pass over 
 with the aqueous vapour, are separated mechanically from the watery distillate, and 
 subjected to fractional distillation, the portions which distil at constant boiling points 
 or between narrow limits of temperature being collected apart. Many volatile oils 
 have the composition of aldehydes, and these are separated from mixtures containing 
 them, by agitation with a saturated solution of acid sulphite of sodium, with which they 
 form crystalline compounds. 
 
 In most cases, however, more information will be obtained concerning the best 
 method of procedure in any particular case, by consulting the methods which are 
 actually in use for separating special substances from complex mixtures in which they 
 occur, than from any general rules : see for example the articles ALKALOIDS (DETECTION 
 OF), BONE-OIL, CINCH ON A- BARK, OPIUM, for the methods of separating alkaloids ; the 
 articles BILE, OLEIC ACID, STEARIC ACID, URIC ACID, &c., for the methods of separating 
 acids ; and the articles ALBUMIN, GLYCERIN, SUGAR, &c., for the methods of separating 
 neutral bodies. 
 
 Examination of Animal Substances: Zoochemical Analysis. The 
 general directions just given for the proximate analysis of complex organic bodies, are 
 for the most part equally applicable to vegetable and to animal substances : but the 
 proximate principles of the animal body being less numerous than those of the 
 vegetable kingdom, where distinct proximate principles occur in every natural order 
 and in many individual species, it is somewhat easier to lay down a systematic course 
 for the qualitative analysis of animal substances. The following is the method given 
 by Gorup-Besanez, in the Handworterbuch der Ckemie, 2 te Aufl. i. 984. 
 
 a. For liquids. The physical characters must first be examined. Any turbidity or 
 sediment occurring in the liquid is to be examined by the microscope for the detection 
 of crystals., or bodies of any other definite form. An acid reaction of the liquid indi- 
 
ANALYSIS (ORGANIC) PROXIMATE. 251 
 
 cates the presence of free acids or of acid salts ; an alkaline reaction, that of free 
 alkalis, alkaline carbonates or phosphates (as in blood, blood-serum, and serous transu- 
 dates, or of ammonia resulting from decomposition (as in mine). A coagulum forming 
 spontaneously, after a while, in a liquid originally clear, generally consists of fibrin ; it- 
 may also consist of organised bodies, a question to be decided by examination with the 
 microscope. 
 
 The liquid, clarified, if necessary, by filtration or straining, is now to be examined 
 as follows. 
 
 1. A portion of it is heated in a test-tube to the boiling point, acetic acid being 
 added, before the boiling heat is attained, in sufficient quantity to produce a faint 
 acid reaction, in case the liquid was originally neutral or alkaline. 
 
 0. If no distinct coagulum is formed, albumin is absent: pass on to (2). 
 
 b. A distinct coagulum or turbidity is produced : Divide the liquid into two portions. 
 To one portion add a few drops of dilute hydrochloric acid. If the precipitate dis- 
 appears, albumin is absent, but earthy phosphates are probably present. Look for 
 them by the microscope or by chemical tests. 
 
 If the coagulum or turbidity does not disappear, add hydrochloric acid and heat to 
 the boiling-point; if it dissolves gradually, with blood-red colour, albiimin is present : 
 for a confirmatory test, add a few drops of nitric acid to a small quantity of the 
 original liquid. 
 
 N.B. If the coagulum formed by boiling the liquid, or the liquid itself, has a reddish- 
 tinge, h sematin and globuli n may be present. The coagulum is then to be digested 
 in alcohol containing sulphuric acid, and the liquid treated with the tests specially 
 adapted to the discovery of those compounds. 
 
 2. The liquid in which no coagulum is produced by boiling, or the liquid filtered 
 from the coagulum in the contrary case, may still contain the following albuminoidal 
 substances: paralbumin and metalbumin, casein andglobulin. 
 
 If only a turbidity was produced on boiling the liquid, paralbumin or metal- 
 bumin may be present. Add acetic acid during ebullition; if the liquid then becomes 
 turbid or deposits flocks, and yields a turbid filtrate, if it also gives a precipitate with 
 ferrocyanide of potassium and nitric acid, and the last-mentioned precipitate is inso- 
 luble in excess of nitric acid, paralbumin is present. Then look for metalbumin 
 with alcohol and ferrocyanide of potassium. If alcohol produces a precipitate soluble 
 in a large quantity of water, but ferrocyanide of potassium produces no precipitate, 
 metalbumin is present. 
 
 If the liquid remains perfectly clear on boiling, it may still contain the following 
 albuminoid substances and their derivatives ; casein, globulin, glutin, chondrin, 
 pyin, and mucus. 
 
 A sample of the liquid is mixed with ferrocyanide of potassium. If it remains 
 clear, casein and globulin are absent: pass on to (3). 
 
 If a precipitate is formed, test for casein with solution of chloride of calcium and 
 boiling, also with calf's rennet; for globulin, by observing whether a precipitate is 
 formed by neutralising the solution after it has been made acid or alkaline. 
 
 3. To a portion of the liquid add acetic acid. If it remains clear, pyin, mucus, 
 and chondrin are absent: pass on to (4). 
 
 A precipitate is formed : test the solution with corrosive sublimate. If no precipi- 
 tate is formed, pyin is absent. The occurrence of a precipitate indicates the presence 
 of py i n, which may be verified by tincture of galls and neutral acetate of lead. If the 
 corrosive sublimate produces merely a turbidity, chondrin is perhaps present. Con- 
 centrate a portion of the liquid: the formation of a jelly indicates chondrin, the 
 presence of which may be confirmed by its behaviour to alum and metallic salts. 
 
 4. The liquid in which acetic acid produced no precipitate may yet contain glutin. 
 Concentrate a portion strongly, and leave it to cool: the formation of a jelly will then 
 indicate glutin, which may be further tested with corrosive sublimate. 
 
 5. The original liquid or of it contained albumin, the liquid freed from that com- 
 pound by boiling is concentrated by a gentle heat to | or i of its volume, then heated 
 to boiling and left to cool. 
 
 If no precipitate forms, the liquid is probably free from u rates : pass on to (6). 
 
 If a precipitate is formed, add acetic acid. If the hitherto amorphous masses are then 
 sera under the microscope to assume the form of rhombic tablets, uric acid is present 
 and may be further tested with nitric acid and ammonia. 
 
 A crystalline precipitate not altered by acetic acid points to the presence of sul- 
 phate of calcium, or phosphate of magnesium, which may be further sub- 
 mitted to microscopic and chemical examination. The precipitate, if crystalline, may 
 also contain allantoin, tyrosin, hippurate of calcium, and benzoic acid. 
 Microscopical examination and the general behaviour of the substance must then de- 
 termine the further tests to be applied. 
 
252 ANALYSIS (ORGANIC) PROXIMATE. 
 
 6. The concentrated liquid in which no precipitate is formed by boiling and sab- 
 sequent cooling, or the liquid filtered from such a precipitate, is evaporated to a syrup 
 on the water-bath, and left to itself for a considerable time. 
 
 If crystals gradually form, it is left to stand as long as they continue to increase. 
 They may consist of creatine, creatinine, glyccocoll, leucine, allantoin, 
 taurine, sarcosine, iuosite, alkaline hippurates, chloride of sodium 
 and other inorganic salts. 
 
 It must in the first place be determined whether these crystals are organic or 
 inorganic. In the former case, they must be tested especially for nitrogen, sulphur 
 and phosphorus (p. 221), their chemical character determined as nearly as possible, 
 and the further examination regulated accordingly. In the latter case, they must be 
 treated by the methods of inorganic analysis. If they blacken when strongly heated, 
 but also leave a fixed residue, they probably consist of an organic acid combined 
 with an inorganic base : in that case, the fixed residue will effervesce strongly with 
 acids. 
 
 7. The syrupy residue itself, or the liquid separated from the crystals which have 
 formed in it is evaporated nearly to dryness, and the residue exhausted with alcohol 
 of specific gravity 0-833. 
 
 a. A portion of the alcoholic solution concentrated and then diluted with water, is 
 tested with nitric acid containing nitrous acid, for b i 1 e-p igment: b. A second portion 
 treated in like manner, is tested with sugar and sulphuric acid for the acids of bile: 
 c. A third portion is evaporated nearly to dryness, the residue dissolved in water, and 
 the solution examined by Trommer's or Fehling's test for s u g ar : d. A larger portion 
 of the alcoholic solution is evaporated to a small bulk, the cooled residue treated with 
 nitric acid free from nitrous acid, and the vessel immersed in ice-cold water or in a 
 freezing mixture. A laminar crystalline precipitate exhibiting the micro-crystalline 
 characters of nitrate of urea, indicates urea (care must be taken to distinguish it 
 from nitrates of the alkalis). A crystalline precipitate appearing after some time, or 
 more quickly after previous heating, indicates hippuric or benzoicacid, the pre- 
 sence of which must be verified by the microscope and by chemical reactions: e. Mix a 
 portion of the concentrated alcoholic extract with a syrupy solution of chloride of zinc : 
 if a crystalline precipitate forms, it may contain creatine and creatinine: if no 
 such precipitate appears after a considerable time, creatine is certainly absent: 
 f. The last portion of the concentrated alcoholic extract, which will exhibit a strong 
 acid reaction, if any free acid is present, is to be heated with oxide of zinc, filtered 
 hot, and a drop left to evaporate on a glass plate : if lactic acid is present, the cha- 
 racteristic club and tun-shaped crystals of lactate of zinc will be seen by examination 
 with the microscope. The presence of lactic acid may be confirmed by preparing a 
 pure salt of the acid from a larger quantity of the liqiiid. 
 
 8. The residue insoluble in alcohol may contain, in addition to inorganic and so- 
 called extractive matters, uric acid, guanine, hypoxanthine, and albumi- 
 nates not precipitated by boiling. It must be exhausted with water, which takes \vp 
 casein, pyin, and extractive matters, together with soluble salts, then with dilute 
 potash solution, which dissolves uric acid, hypoxanthine, and guanine, and lastly, with 
 dilute hydrochloric acid. What then remains may contain albuminates which have 
 become insoluble, mucus, and perhaps also silica. All these substances must be 
 further looked for by special tests. 
 
 9. Part of the original liquid is evaporated to dryness, and the residue, pulverised 
 if possible, is exhausted with ether. The ethereal extract, chiefly containing fats in 
 solution, is evaporated and further examined (see FATS and GLYCEKIDES). The residue 
 insoluble in ether is incinerated, and the ash examined by the methods of inorganic 
 analysis. 
 
 /8. Tissues and Organs. In the analysis of animal tissues, it is absolutely necessary 
 to operate with considerable quantities of material, not less than 20 pounds ; otherwise 
 a very tedious investigation may be gone through without any satisfactory result. 
 
 The tissue is first carefully comminuted and completely exhausted with cold water ; 
 the extract is freed from albumin by boiling, and to the filtered liquid a concentrated 
 solution of caustic baryta is added as long as any precipitate or turbidity is produced. 
 The precipitate may contain phosphate of barium, phosphate of magnesium, 
 sulphate of barium, uric acid, and hypoxanthine. The filtrate is evaporated 
 to a syrup over the water-bath, care being taken to remove any mucous films like 
 casein that form during the evaporation. These generally consist of carbonate of 
 barium or phosphate of magnesium, but may also contain uric acid, hypoxanthine, 
 or barium-salts of organic acids; they must, therefore, not be throAvn away. As 
 soon as the filtrate is concentrated to the consistence of a thin syrup, it must be left 
 to evaporate spontaneously. If small short colourless prisms form in it, they 
 
ANALYSIS (ORGANIC) PROXIMATE. 253 
 
 probably consist ofcreatine; as soon as they appear to be completely deposited, 
 they are to be separated from the mother-liquor, recrystallised, and submitted to 
 farther examination. 
 
 The mother-liquor is then further evaporated, and mixed with small portions of 
 alcohol, till a milky turbidity is produced, after which the mixture is left to itself for 
 a few days ; if granular, laminar, or needle-shaped crystals form in it, they may con- 
 tain, besides creatine and phosphate of magnesium, inosate of potassium and 
 in o sate of barium. To obtain the inosic acid, dissolve the deposit in hot water, 
 add chloride of barium, purify the inosate of barium which separates by crystallisation, 
 and separate the inosic acid by precipitation with dilute sulphuric acid. 
 
 The liquid separated from the deposit of inosates is now to be mixed with a fresh 
 portion of alcohol, whereupon it generally separates into two layers, the lower being 
 syrupy, the upper more mobile. The upper layer is decanted, and the lower is mixed 
 with an equal volume of ether, which generally causes a fresh separation. The lower 
 stratum thus formed may contain alkaline lactates, inosite, and salts of the 
 volatile fatty acids; the upper, creatinine and leucine. The ether-alcoholic 
 liquid is evaporated and left to crystallise. If the residue gradually deposits fine 
 laminated crystals, dilute it with a little alcohol, filter off the mother-liquor, and treat 
 the crystals with boiling alcohol ; they may contain creatine and creatinine. The 
 creatine separates immediately as the filtrate cools ; the creatinine crystallises from 
 the mother-liquor. 
 
 The heavy syrupy liquid mixed with the mother-liquor of the creatine and creatinine 
 is supersaturated with dilute sulphuric acid, in order to precipitate all the baryta, and 
 the filtrate is distilled to obtain the volatile acids. The residue of the distillation, if 
 shaken up with ether, may perhaps yield lactic and succinic acids. 
 
 The residue of the distillation, after being freed from these acids, is mixed with 
 strong alcohol, till it becomes turbid, and left at rest. Sulphate of potassium then 
 crystallises out, and on repeatedly adding fresh portions of alcohol, more sulphate of 
 potassium, together with inosite, which must be separated from the sulphate of 
 potassium, as far as possible by mechanical means, and then by recrystallisation from 
 a small quantity of warm water. To obtain hypoxauthine and uric acid from the 
 baryta-precipitates, viz. that which separated in films at the beginning of the process, 
 and that which was produced by adding sulphuric acid to separate the volatile acids 
 treat the united precipitates with boiling potash-ley, filter, acidulate with hydrochloric 
 acid, rediesolve the resulting precipitate in potash, and add sal-ammoniac. Uric 
 acid is then precipitated as urate of ammonium, while hyp oxan thine remains in 
 solution, and may be obtained by evaporation as a yellowish- white powder. 
 
 If the filtrate from the coagulum of albumin, after being evaporated to a syrup, 
 does not yield any well developed crystals, but after standing for some time, masses 
 having a crystalline aspect, soft and unctuous to the touch, and appearing under the 
 microscope as yellowish refracting spherules, the presence of leucine may be sus- 
 pected. These masses are then to be separated from the mother-liquor, which, after 
 standing for a longer time, deposits more of them, and the entire product strongly 
 pressed between porous tiles and purified by repeated crystallisation from boiling 
 alcohoL If tyro sine is present, it covers the filtrate, after it has been freed from the 
 albumin-coagulum and evaporated, with numerous stellate groups of slender needles, 
 which for the most part remain undissolved when treated with alcohol. They may be 
 dissolved in boiling water, whence they separate on cooling, purified by solution in 
 hydrochloric acid, with addition of acetate of potassium, and boiling, and then further 
 examined. 
 
 The mother-liquors from the leucine and tyrosine deposits are examined as above 
 for volatile acids, lactic acid, succinic acid, inosite, &c. 
 
 Another process for the examination of animal tissues is given by Stiidelcr and 
 Cloetta : 
 
 The extracts obtained by maceration and pressing are boiled with a few drops of 
 acetic acid to coagulate albumin and colouring matter of blood, and the strained 
 licniid, after being evaporated over the water-bath to ^ of its bulk, is precipitated 
 with eubacetate of lead. The precipitate, which may contain uric aci d and inosite, 
 is collected on a filter and washed ; the filtrate is freed from excess of lead by sul- 
 phuretted hydrogen, and evaporated to a syrup; the residue, which generally contains 
 alkaline acetates, is freed from these compounds by digettion in cold weak alcohol ; 
 sulphuric acid diluted with alcohol is then added as long as a precipitate of alkaline 
 sulphates continues to form ; and the excess of sulphuric acid is removed by careful 
 addition of baryta-water. The clear filtrate evaporated till it no longer becomes 
 permanently turbid when mixed with an equal volume of absolute alcohol, is heated 
 till the turbidity disappears, and then left at rest. Any crystals which separate must 
 
254 ANALYSIS (VOLUMETRIC). 
 
 be further examined: they may consist of creatine, but also cf tyrosine and 
 taurine, which last compound has lately been found by Cloetta in the tissue of the 
 lungs. The mother-liquor of the crystals, if carefully evaporated to a smaller bulk, 
 deposits any leu cine that may be present. 
 
 The precipitate produced by subacetate of lead is washed, suspended in water, and 
 decomposed by sulphuretted hydrogen. If the liquid filtered from the sulphide of lead 
 deposits, after some time, small white crystalline grains, exhibiting under the micro- 
 scope the forms of uric acid, they must be collected and examined for uric acid by 
 the murexide test (Umc ACID). The liquid filtered from the uric acid is evaporated 
 over the water-bath, till a sample mixed with alcohol becomes permanently turbid. 
 The entire liquid is then mixed with an eqiial volume of alcohol, and warmed till the 
 turbidity disappears. If after some days, a deposit forms on the bottom and sides of 
 the vessel, consisting of crystalline masses, which, when recrystallised from water, form 
 rhombic prisms insoluble in alcohol and ether, having a pure sweetish taste, and leav- 
 ing no residue when burnt, inosite is probably present, and must be sought for by 
 other tests. [For further details, and for the quantitative analysis of animal substances 
 see Lehmann, Lehrb. d. physiolog. Chem. 2 te Aufl. Leipzig, 1853; Heintz, Lehrb. 
 d. Zoochemie, Berlin, 1853; Robin et Verdeil, Traite de Chimie anat. et physiol. 
 Paris, 1858 ; Gorup-Besanez, Anleitung zur zoochem. Analyse, 2 te Aufl. Niirnberg. 
 1854.] 
 
 AZJAX.YSZS (VOXiUXVSETRXC) of LIQUIDS and SOLIDS. The method 
 usually employed by chemists to determine quantitatively the constituents of a mix- 
 ture, consists in separating them out one after the other, either in the pure state, or in 
 the form of some compound of known composition, and weighing the products. Every 
 one who has occupied himself with such separations knows how much time they usually 
 require ; indeed the value of an analytical result is very often much less than that oi 
 the time and trouble spent upon its determination. We are indebted to the sagacity 
 of Gay-Lussac for the introduction of a new principle in analytical chemistry, which in 
 many instances obviates the inconvenience mentioned. This consists in submitting the 
 substance to be estimated to certain characteristic reactions, employing for such 
 reactions liquids of known strength, and, from the quantity of the liquid employed, 
 determining the weight of the substance to be estimated by means of the known laws of 
 equivalence. Let us, for example, consider the problem which suggested to Gay- 
 Lussac the idea of this method. Suppose it be required to determine the amount of 
 silver in an alloy of silver and copper. The older analytical method consists in dis- 
 solving a weighed quantity of the alloy in nitric acid, precipitating the silver as 
 chloride by the addition of hydrochloric acid, then filtering, washing, fusing, and 
 weighing the resulting chloride of silver. From the known fact that chloride of silver 
 contains if^.^ of its weight of silver, the amount of silver in the alloy is calculated. 
 The same result is evidently obtained by preparing a solution of chloride of sodium of 
 known strength, and ascertaining how much of the solution is necessary and sufficient 
 to precipitate the silver as chloride of silver from a solution of a weighed quantity of 
 the alloy in nitric acid. The weight of the precipitated silver may be determined 
 from the amount of the chloride of sodium employed; because it is known that 58'5 
 parts by weight of chloride of sodium are exactly sufficient to convert 108 parts of 
 silver into chloride of silver. 
 
 The liquid reagents of known strength employed in determinations of this nature are 
 called "standard solutions." The amount of standard solution employed in a deter- 
 mination may be estimated either by weight or by volume ; but inasmuch as the 
 latter method has been found easier of application, it is now universally employed ; 
 and hence the method of analysis based upon the use of standard solutions is called 
 "volumetric analysis." At first glance it would seem that nearly all analytical 
 methods based upon weight might be transformed into processes by volume, as in the case 
 of the silver determination above quoted. This is, however, not always possible. A reac- 
 tion to be applicable in volumetric analysis must satisfy two conditions. (1.) It must not 
 occupy much time ; precipitations, for instance, which take place gradually are at once 
 to be rejected. (2.) The termination of the reaction must be recognisable with ease and 
 certainty. Hence the number of possible volumetric processes is much limited. On 
 the other hand numerous reactions inapplicable in weight-analysis furnish excellent 
 means for volumetric determinations. 
 
 It is proposed in this article to give a short introduction to volumetric analysis, 
 and for this purpose the subject will be divided into three parts : 
 
 I. Description of the necessary apparatus. 
 II. General rules for the preparation of standard solutions. 
 III. Description of the most important volumetric methods as yet discovered. 
 
ANALYSIS (VOLUMETRIC). 255 
 
 I. Apparatus : description, use, and verification. Besides the apparatus necessary 
 for ordinary chemical operations, such as beakers, basins, &c., the performance of 
 volumetric analysis requires: (1.) a delicate balance and weights. (2.) Graduated 
 glass vessels for the measurement and preparation of the standard solutions. A balance 
 is necessary for the preparation of the standard solutions, and for weighing the sub- 
 stances to be analysed. A good analytical balance capable of weighing 100 grammes 
 is quite sufficient for both purposes. To those who have many volumetric analyses to 
 perform, a small light sensible balance with short arms is of great use. Such balances 
 admit of more rapid weighing than can be obtained by the ordinary laboratory 
 balances. 
 
 The absolute magnitude of the units of weight and measure adopted, may of course 
 be chosen at pleasure. But the French decimal system of weights and measures offers 
 so many advantages, chiefly on account of the simple relation which it establishes 
 between the units of measure and weight, that its employment in the sequel in all data 
 of weight and measure needs no justification. 
 
 In order to be able to measure the standard solutions accurately, certain precautions 
 are to be observed which we wil now proceed to consider more particularly. 
 
 When an aqueous solution is poured out of a vessel, the vessel is, as is well known, 
 never completely emptied ; a small portion of the solution remains always upon the 
 the sides, even after the vessel has been long held in an inclined position. In using 
 a measure for liquids we must, therefore, be careful to note whether the dry vessel, 
 when filled up to a certain line, holds the required volume, or whether such volume is 
 delivered from the vessel when it is emptied in a certain manner. In the first case 
 the vessel is said to be graduated for the contents; in the second for delivery 
 (a F ecoulement). The reading off is performed by bringing the eye and the surface of 
 the liquid into one horizontal line, and noting what division of the volumetric instru- 
 ment is opposite to the liquid surface. Now aqueous liquids which are enclosed in 
 cylindrical glass vessels, always show a concave surface, which is the more strongly 
 curved the narrower the vessel. But a curved surface is of course opposite to many 
 points of the scale at once. In order to avoid the ambiguities which are here intro- 
 duced a definite method of reading off must be invariably adopted. The following 
 has been found practically the best. A small piece of black paper is fastened a few 
 millimetres below the surface of the liquid by means of a caoutchouc ring; the instru- 
 ment is brought into an exactly vertical position, one eye is closed, and the other 
 brought to the right elevation. The meniscus then appears by transmitted light, 
 sharply bounded below by a black line, by means of which it is easy to see with 
 what point of the scale the former coincides (see ANALYSIS OF GASES). In order to 
 ensure a fixed point of sight the eye, the meniscus, and a distant horizontal line, of 
 about the same elevation as the eye, are either brought into one horizontal line, or the 
 instrument is placed at a short distance before a vertical strip of mirror, and the eye 
 is brought into such a position that the image of the pupil and that of the meniscus 
 may coincide as nearly as possible : the scale is then read off. 
 
 It must be mentioned that the volume of every body varies with the temperature, 
 and that consequently the divisions on a measure for liquids, as well as the strength 
 of a standard solution, are applicable for one temperature only. The expansion of the 
 glass is so small that it may be always neglected in volumetric analyses. A glass 
 vessel, for instance, which holds a liter at 15 C. contains at 15 + 10 J , one litre + 
 0-27 c.c. : now 0-27 c.c. ; are only the -^~ of a litre. The expansion of liquids Is 
 greater, and must be taken into account in exact experiments. 
 
 This is especially to be attended to when volumetric instruments are to be graduated 
 by determining the weight of water which they hold. In this case the correction for the 
 expansion of water by heat is not the only one to be made. Since one gramme is by 
 definition the weight in vacuo of one cubic centimetre of water at + 4 C., the volume of 
 a given quantity of water in c.c. is never expressed by the same number as its apparent 
 weight in grammes, even at + 4 C. There is of course no necessity for employing 
 the real cubic centimetre in volumetric analyses ; but, as everything connected with 
 weights and measures should be as precise as possible, we think it advisable to use 
 the words litre, cubic centimetre, &c., in their strict sense.* We therefore give the 
 following table, by means of which the apparent weight of a certain required volume 
 of water may easily be found. 
 
 * There are, even in scientific researches, cases in which absolutely correct measures must be em. 
 ployed; lor instance, 1 litre of air of C. has the weight of 1-293 grms., only when its tension ia 
 equivalent to the pressure of a mercury column 076 real metres high, the litre being the volume cf s 
 quantity of water ot 4 C., which balances in vacuo the kilogramme employed. 
 
256 
 
 ANALYSIS (VOLUMETRIC) 
 
 The weight of 1000 c.c. of water of t C. when determined by means of brass 
 weights in air of t C. and of a tension of 076 metres, is equal to 1000 .r grms. 
 
 t~ 
 
 X 
 
 
 
 1 
 
 2 
 1 15 
 
 3 
 
 4 
 
 ri2~ 
 
 5 
 
 6 
 1-14 
 
 7 
 
 8 
 l-.'l 
 
 9 
 
 1-27 
 
 10 
 1-34 
 
 11 
 
 U 
 
 l.&j 
 
 13 
 1-63 
 
 14 
 
 15 
 
 l"2.T 
 
 1 '^0 
 
 Ml 
 
 1-1-2 
 
 1-16 
 
 1-43 
 
 1-76 
 
 1 81) 
 
 t 
 
 1G 
 
 17 
 
 18 
 
 19 
 
 20 
 
 21 
 
 22 
 
 23 
 
 21 
 
 25 
 
 26 
 
 27 
 
 28 
 
 29 
 
 30 
 
 31 
 
 X 
 
 204 
 
 2-20 
 
 2-;7 
 
 2-:V> 
 
 2-74 
 
 2-95 
 
 3-17 
 
 339 
 
 3<,3 
 
 3-88 
 
 4-13 
 
 4-39 
 
 4-G7 
 
 4-94 
 
 5-24 
 
 
 When the barometer stands at 76 + n centim., every # is to be replaced by x + 
 0'014 n. The variations of atmospheric pressure may however be neglected, unless 
 a very great degree of exactness is required. 
 
 If the strength of a standard resolution is known for one temperature, the strength 
 corresponding to another temperature can only be calculated, if the rate of expansion 
 by heat of the liquid is known. It would lead to entirely wrong results if such cal- 
 culations were founded on the known expansion of pure water, as experiment has 
 shown that even weak solutions of salts and acids expand far more than water 
 (see Gerlach " Specifische G-ewichte der Salzlosungen, &c.," Freiberg). As long 
 as the expansion of the commonly used standard solutions is not directly deter- 
 mined, it is advisable to estimate the strength of such solutions not only by volume, 
 but also by weight, which is easily done by weighing a known volume of the liquid 
 immediately after its strength has been determined. The ratios of the weight of the 
 solution to the weight of active substances in it, is of course independent of 
 temperature. 
 
 It is a matter of course that such corrections are appropriate only where the errors 
 from other sources are not greater than the corrections themselves. 
 
 "We may now proceed to describe the separate instruments. 
 
 1. Pipettes. Glass vessels of forms shown in figs. 40* and 41, provided with a single 
 mark upon the narrow neck, and which are only graduated for delivery. In using 
 them, they are filled, at a little above the mark, by suction, and then closed above with 
 the forefinger of the right hand. The lower point is brought in contact with a wet 
 piece of glass ; the liquid is allowed to flow oat, by very gentle displacement of the 
 finger, as far as the mark ; and the finger is then removed, to allow it to run out into 
 the vessel employed. The drop of liquid in the point of the pipette is to be kept in 
 exactly the same conditions as during the marking of the pipette ; i. e. it is either 
 totally neglected, or it is partly removed by holding the point against the wet side of 
 the glass, or it is to be blown out entirely. If the same method of evacuation be 
 always faithfully followed, we may assume that, with all thin liquids, equal volumes 
 remain adhering to the sides of the vessel. 
 
 It is convenient to be provided with such pipettes containing 100 c.c., 50 c.c., 20 c.c., 
 10 c.c., and 5 c.c. Pipettes of 10 and 5 c.c. may conveniently have the form of Jig. 41, 
 larger ones the form of fig.^Q*. It seldom happens that we have to make pipettes our- 
 selves, as they may be bought at a low price; but they should always be verified. 
 This is easily done by filling them with water of a known temperature, pouring this 
 into a tared flask, and weighing. The volume of the water may then be found from 
 its weight by means of the table above given. 
 
 2. Pipettes which are divided throughout their whole length and graduated for 
 delivery. It is sufficient to have one of 50 c.c., which is divided in half c.c. {fig. 42), 
 and several of 2 to 3 c.c., divided into -i c.c. (fig. 43). 
 
 3. Flasks, graduated for the contents (fig. 44), in various sizes, from ~ litre to 
 5 litres. They may be easily made by making an arbitrary mark upon the neck of 
 the flask, and then measuring the volume by pipettes. It is more exact to weigh 
 the contained water. It is convenient if, but not absolutely necesssary that, the volumes 
 of these flasks should be whole numbers, such flasks being used only for the prepara- 
 tion of standard solutions. 
 
 4. For measuring the liquids used in an analysis the burette is most generally 
 employed. This is an ingenious instrument invented by Gay-Lussac. Upon a glass 
 tube (fig. 45) about 16 18 mm. wide and 30 centim. long, a narrow tube is fused at d, 
 carried up close along the wide tube to about 2 ctm. from its upper end, and there 
 (at c) bent and cut off in the manner shown by the figure. The divisions of f c.c. 
 begin about one ctm. below c, and the instrument is graduated " for delivery." In using 
 the burette it is washed out with some of the standard solution, then filled to ; the 
 point c is slightly greased, and the required quantity of liquid is poured out of the 
 narrow tube. 
 
 After some practice it is easy to allow the liquid to flow out either in a stream 
 
OF LIQUIDS AND SOLIDS. 
 
 257 
 
 or in drops. The volume must not be read off before the surface has attained a constant 
 height. Tenths of cubic centimetres may, after some practice, be easily judged of by 
 the eye in burettes graduated to half cubic centimetres. It is erroneous to suppose that 
 greater accuracy is attained by employing narrower tubes. The gain in accuracy due 
 to the increased distance of the divisions is lost, because in narrower tubes, the 
 meniscus is less sharply defined, and the quantity of liquid adhering to the sides is 
 less constant. A burette of the dimensions given, contains 50 to 60 c.c., an amount 
 more than sufficient for most analyses : larger burettes are inconvenient. If more 
 than 50 c.c. liquid are required in analysis, the greatest portion is measured off in a 
 pipette. (40*.) and the remainder added from the burette. In cases where greater 
 accuracy is required than can be attained by the burette, the latter is replaced by the 
 use of several pipettes. 
 Mohr has substituted for Gray-Lussac's burette a simple divided tube (Jig, 46), pro- 
 
 42. 
 
 40*. 
 
 41. 
 
 43. 
 
 n 
 
 \ 
 
 \/ 
 
 45. 
 
 46. 
 
 vided below with a caoutchouc tube, which is closed by a spring clamp (fig. 47) 
 (Quetsch-Hahri) made of brass wire. Where a great number of analyses of the same 
 kind have to be performed, Mohr's burette is much to be preferred to Gay-Lussac's 
 In scientific laboratories, however, where a greater diversity of analyses occur the old 
 form is preferable, inasmuch as caoutchouc is acted upon by some solutions which 
 are frequently employed. 
 
 The verification of a burette is performed either by the balance or by the pipettes 
 described in (1). 
 
 II. Preparation of the Standard Solutions. Standard solutions maybe divided into 
 (1) such as are immediately prepared by weighing a substance of known composition, 
 dissolving it and diluting to a certain volume ; (2) such as are prepared by approxi- 
 mate mixture and subsequent exact analysis. The preparation of the first kind re- 
 
 VOL. I. . 
 
258 ANALYSIS (VOLUMETRIC) 
 
 quires no description. The preparation of the second may be effected by a kind of 
 successive approximation, which is best described by an example. 
 
 Let it be required to prepare a standard solution of sulphuric acid containing t 
 grammes of hydrate of sulphuric acid S0 4 H 2 in 1 litre. The table given by Bineau of 
 the relation between the specific gravity and strength of sulphuric acid affords the best 
 means for determining the strength to the first approximation. Pure sulphuric acid 
 (monohydrate, S0 4 H 2 ) is diluted with about its own weight of water; the mixture is 
 allowed to cool, and its specific gravity is quickly and accurately determined by measur- 
 ing 100 c.c. in a pipette, weighing this, and dividing the weight (in grammes) by 100. If 
 the temperature be observed, the percentage of monohydrated sulphuric acid (p} may 
 be determined by the table, to within a hundredth of its true value. According 
 
 to the result of this determination every - 100 = g grms. of the solution are di- 
 luted with water up to 1 litre. From Bineau's table (see SULPHURIC ACID) the 
 specific gravity ($) of the required /solution may be seen. To every q grms. of acid, 
 1000 S q w grammes of water have to be added. An analysis performed with 
 this mixture generally shows that it contains not t but t l grms. in 1 litre. Two cases 
 are now possible : 
 
 (1) t 1 is greater than t. It is clear that the quantity t } of sulphuric acid contained 
 
 in 1 litre is sufficient for = (1 + A) litre. With every 1 litre of the mixture, 
 
 A litre of water must be mixed, in order to bring it to the right strength. (2) i 1 is 
 
 ^i 
 
 less than t. From t } grms. of sulphuric acid only = (1 A) litre of standard solu- 
 tion can be formed. Hence 1 litre of our mixture may be regarded as a mixture of 
 (1 A) litre of right standard solution and A litre of water. Hence to every litre of the 
 solution as much of the acid of p per cent, must be added as is sufficient to form the 
 right standard solution, with A of litre water ; and since by mixing q grms. of the p 
 per cent, acid with w grms. of water, we had obtained a mixture of nearly the right 
 strength, it follows that the quantity of strong acid which must be added to every litre 
 
 is ( q I grammes, neglecting an error which need not be considered, if A is a 
 
 small fraction. 
 
 After performing these operations, we must determine by experiment how nearly 
 we have arrived at the required strength, and, if necessary, make a second cor- 
 rection. If the corrections required are great, it will be almost invariably found, 
 on performing the analysis, that the strength required has not been exactly attained, 
 however carefully the mixture of the liquids may have been made. This is the case 
 even if the above described approximate synthesis is replaced by a theoretically exact 
 one, this cause of the inaccuracy being, that in the measurement and mixture of large 
 quantities of liquids, small errors of measurement and losses are difficult to avoid, and 
 that the contraction of the mixture has been neglected. If, on the other hand, the 
 solution to be corrrected is already so nearly right, that its strength differs by only 
 1 or 2 per cent, from that which is required, the result will be satisfactory, even if the 
 volume of the liquid taken was only approximately determined, provided the analysis 
 was performed accurately, and the measurement of the small quantities of water or 
 acid which were added, were made with sufficient care. 
 
 If, for instance, we consider the case (1) and assume that the volume of the acid to 
 be Corrected was found to be n litres, while in fact it was n (1 + a) litres, the quan- 
 tity of water to be added would then be, not n A litres but w A (1 + a). The resulting 
 
 >lu 
 
 A (1 + a) _ n A = n A a. If, 
 for instance, it is found that a = i, which seldom occurs, if moderate care is employed, 
 and A = yi^, then the volume of the mixture would be n ^^ litres too small, and 
 consequently the amount of sulphuric acid in 1 litre would be too large by about ^^ 
 of its actual quantity. Similar considerations are applicable to case (2), and lead to 
 the conclusion that in the preparation of large quantities of liquids, according to the 
 method just described, large measures accurately divided are not necessary. Such pro- 
 cesses are conveniently performed in large cylindrical bottles, which are divided down 
 the side with divisions corresponding to entire decilitres. As the liquid in such cas< s 
 is not transferred from one vessel to the other till it is quite prepared, loss is easily 
 avoided. 
 
 The strength of a solution is best noted by giving the number (n) of gramme- 
 atoms of the active substance which it contains in 1 litre. By "gramme-atom" 
 we understand a number of grammes equal to the atomic weight of the substance 
 (H = 1), for instance, 108 grammes silver, 28 iron, 35*5 chlorine, &c. It is clear that 
 the calculations are hereby simplified. For instance, 1 litre of solution of silver, con- 
 
OF LIQUIDS AND SOLIDS. 259 
 
 taining n atoms ( = n x 108 grms.) of silver exactly precipitates n x 35'5 grms. of 
 chlorine, n x 80 grms. of bromine, n x 127 grms. of iodine. It is also evident that 
 calculation will be facilitated by making n a small number. If it can be done without 
 loss of time, it is in fact advisable so to adjust the strength of the standard solution 
 that n = 1, f, ^ &c. 
 
 It is of the highest importance that the standard solutions should remain of constant 
 strength. To ensure this condition, they must be carefully protected from evaporation 
 and other hurtful influences. Large quantities may be preserved in bottles of 1 or 2 
 litres capacity, provided with well ground stoppers. Bottles which are not in daily 
 use should have have their stoppers greased and bound over with bladder or sheet 
 caoutchouc. 
 
 III. Description of the most important Volumetric processes hitherto employed. 
 Among the many volumetric methods hitherto discovered, those only are of general 
 scientific interest by help of which the analysis of a whole series of bodies can be made 
 with one, or at least, a few standard solutions. These alone will be more particularly 
 considered here. For the many methods applicable in special cases, reference must be 
 made to the several articles of this work. 
 
 Volumetric determinations may be classified as follows, according to the principles 
 on which they are based : 
 
 1. Analysis by Precipitation. The quantity of the substance to be determined, is 
 derived from that of the reagent required to separate it out in an insoluble state. 
 
 2. Analysis by Saturation. The quantity of a base or an acid is measured by the 
 quantity of acid or base which is necessary to convert it into a neutral salt. 
 
 3. Analysis by Oxidation and Seduction. The quantity of substance to be deter- 
 mined is found by the quantity of chlorine, bromine, iodine, or oxygen to which it is 
 equivalent (regarded as oxidant), or by the quantity of chlorine, bromine, iodine, or 
 oxygen which it requires to pass from a lower to a higher stage of oxidation. 
 
 1. ANALYSIS BY PBECTPITATION. Of the numerous methods belonging to this divi- 
 sion, we will here consider those only which depend upon the insolubility of the com- 
 binations of silver with the halogens (chlorine, bromine, iodine, cyanogen). 
 
 If the neutral or slightly acid solution of a chloride, bromide, iodide, or cyanide, 
 is mixed with a solution of nitrate of silver, it is well known that an insoluble chloride 
 bromide, &c., of silver is precipitated, while a nitrate remains in solution. For 
 instance 
 
 N0 3 Ag + CINa = ClAg + K0 3 Na. 
 
 All these silver precipitates have the common property of forming, on violent agita- 
 tion, a curdy mass which rapidly subsides. Hence it is possible to recognise exactly 
 the point at which the precipitation is completed. The reactions mentioned may, 
 therefore, be employed, on the one hand, to determine chlorine, bromine, &c., by 
 means of a standard silver solution, and on the other, to determine silver by standard 
 solutions of chlorides, bromides, &c. 
 
 Special processes for the determination of Hydrochloric Acid and Chlorides. 
 Necessary reagents. 
 
 1. Chemically pure silver in the form of foil or wire. 
 
 2. A silver solution (nitrate) containing i gramme-atom (10-8 grm.) silver in 
 1 litre. It is easily prepared by dissolving 10*8 grm. of silver in excess of nitric acid 
 and diluting to 1 litre. 
 
 3. A solution of -^ grm.-atom == 1-08 grm. silver in 1 litre. 
 
 4. A solution of chloride of sodium of ^ grm.-atom (= 5'85) in 1 litre. 
 
 a. 5-85 grm. pure recently fused chloride of sodium is dissolved in water and diluted 
 litre. 
 
 b. A solution of chloride of sodium saturated at ordinary temperatures, has a com- 
 position almost independent of the temperature: it contains in 1 litre, 318'4 grm. of 
 
 NaCl. 18-37 c.c. ( = 3^.4 ) diluted to 1 litre, gives accordingly the standard 
 
 solution required. 
 
 The chloride of sodium solution must, if properly prepared, be exactly equivalent to 
 the silver solution (2). We must never neglect to try whether this is really the case 
 by the method to be described below, and if necessary to make the proper corrections. 
 
 5. A solution of chloride of sodium containing -L grm.-atom in 1 litre = 0'585 grm. 
 
 6. Freshly prepared chloride of silver : this is obtained by mixing equal volumes of 
 (2) and (4), shaking vigorously and pouring off the clear liquid. 
 
 Performance of the Analysis. Let us at first assume that we have an approximate 
 knowledge of the amount of chlorine in the substance to be examined. In this caso 
 a weighed quantity is introduced into a bottle of clear glass with a well-fitting stopper, 
 
 s 2 
 
260 ANALYSIS (VOLUMETRIC) 
 
 dissolved in water or nitric acid, and the previously calculated quantity of strong 
 solution of silver (2) is added from a pipette. The quantity of substance, and that 
 of the water employed in its solution or dilution, are to be so taken that 100 c.c. of 
 the mixture may contain - 4 grin, to 1 grm. silver, and less than about 3 gms. of the 
 dissolved salt. If a mixture has to be examined which is poor in chlorine, this rela- 
 tion is no longer possible. In such cases, enough freshly precipitated chloride of silver 
 (6) must be added to bring the quantity of silver present up to that mentioned. Small 
 quantities of silver-precipitates disseminated through much liquid do not evince that 
 adherence and consequent tendency to subsidence which is necessary for the accurate 
 performance of this mode of analysis. Solutions which are poor in chlorine, such as 
 mineral waters, must be concentrated by evaporation previous to analysis. It is also 
 advisable in such cases not to employ a standard solution of silver, but to weigh 
 metallic silver and dissolve it in a minimum of nitric acid. 
 
 The mixture obtained as above is now to be violently and continuously shaken, till 
 it has lost its first milky appearance, and forms a mixture of curdy chloride of silver 
 in the midst of a clear solution. A speedy clarification is evidence of an excess of 
 silver ; slow subsidence indicates the reverse. 
 
 As soon as the chloride of silver has sufficiently subsided, | c.c. of strong solution 
 of silver must be added, in order to determine whether chlorine is still present in the 
 solution. If no precipitation occurs, the i c.c. silver solution is neutralised by the 
 addition of ^ c.c. solution of chloride of sodium ; the liquid is then shaken, and i c.c. 
 of solution of chloride of sodium being added shows whether silver is in solution. Let 
 us assume, for example, that the addition of the chloride of sodium has shown the 
 presence of silver in considerable quantity. The amount of solution of chloride of 
 sodium, which is exactly equivalent to this, cannot of course be known ; but in every 
 case we are sure of the existence of some maximum value (V c.c.) which certainly 
 
 includes it. c.c. of chloride of sodium solution is then added, the mixture is shaken, 
 and | c.c. of the same solution being added shows whether the precipitation with the 
 
 first quantity was complete or not. In the first case, c.c. of silver are added ; in 
 
 V 
 the second - c.c. of chloride. In both cases, the completion of the precipitation is 
 
 tested by the addition of | c.c. of test solution. By continually adding half the 
 possible maximum of the necessary reagents, we soon arrive at a point when less than 
 I c.c. of one of the two solutions is present in excess. When this point is arrived at, 
 cubic centimetres are added singly of the weaker (^~ atomic) solutions, until the last 
 cubic centimetre leaves the liquid quite clear, This last c.c. is not at all considered, 
 and the one preceding it is considered only of the value of | c.c. In this way, a result 
 is obtained, the error of which corresponds to less than | c.c. of the weak standard solu- 
 tion. It is easily seen that a systematic procedure like that given is quite essential, in 
 order to arrive quickly at a result ; by planless addition of standard solutions, we may 
 lose much time without arriving at any result. As long as ^ atomic solutions are added, 
 it is scarcely necessary to wait for a complete subsidence of the precipitate previously 
 formed. The white cloudy freshly precipitated chloride of silver is easily distin- 
 guished from the previously precipitated, violet-coloured, and coagulated chloride. 
 As soon, however, as we begin to work with ^ atomic solutions, we must always wait 
 for the complete clarification of the liquid before adding a fresh quantity of solution. 
 Weak precipitations are best seen by holding the vessel against the light, with a piece 
 of black paper obliquely behind it. The precipitation can be considered complete only 
 when the last cubic centimetre of solution gives no more turbidity after | to 1 minute's 
 standing. 
 
 Those who make such analyses for the first time, will do well to place in several 
 flasks some chloride of silver (6) and 100 c.c. water, then add to the several flasks 
 |, |, 1, 2 milligrammes of silver; shake, and after subsidence add to each flask 1 c.c. 
 of the 1^0 atomic solution of chloride of sodium. By this means the judgment is 
 greatly assisted in the subsequent actual reactions. 
 
 Experience has shown that it is not expedient to work with less than | grm. of silver 
 at once, and that no greater accuracy is obtained by adding less at once than 1 c.c. of 
 the jig atomic solution ; the termination of the reaction is thereby only rendered more 
 indistinct. 
 
 If it be desired to arrive at the utmost accuracy in such determinations, a second 
 analysis may be made by dissolving 1 grm. or more of silver in nitric acid, adding the 
 quantity of substance necessary for its precipitation, as found from the previous 
 analysis, and completing the precipitation by means of the ^ atomic solution. The 
 determination of atomic weights, performed in this way by Marignac and Pelouze, 
 shows to what great accuracy the process may be brought. 
 
 It has been hitherto assumed that the amount of chlorine in the substance is ap- 
 
OF LIQUIDS AND SOLIDS. 
 
 261 
 
 proximately known. If this is not the case, the definite determination must be preceded 
 by a trial upon a small quantity of the substance. The more exact such trial is made, 
 the quicker will be the performance of the final determination. 
 
 The calculation of the analysis is very simple. The number of atoms of silver, 
 diminished by the number of atoms of Chloride of sodium, added as standard solution, 
 is equal to the number of chlorine-atoms contained in the substance. 
 
 That which is here described for chlorine is applicable, mutatis mutandis, to 'bromine, 
 iodine, and cyanogen. 
 
 The determination of silver by means of chlorine also follows immediately from the 
 above, and requires no further explanation.* 
 
 2. ANALYSIS BY SATURATION. All methods belonging to this division depend upon 
 the fact that potash, soda, ammonia, baryta, strontia, and lime combine easily and 
 directly with acids, and that the corresponding carbonates are fully decomposed in 
 contact with stronger acids, with evolution of carbonic acid. The solutions of the 
 i.eutral salts which the above named bases form with strong acids are without action 
 upon litmus, while the smallest excess of acid or alkali is immediately detected by its 
 reddening or blueing that vegetable colour. 
 
 Reagents. 1. Pure anhydrous monocarbonate of sodium. If this salt be kept ready 
 prepared in powder, it must always be ignited before use. Carbonate of sodium, fused 
 in a platinum crucible, and cast in slabs, is less hygroscopic, but its use must be 
 avoided, since Scheerer has shown that carbonate of sodium loses on fusing a con- 
 siderable part of its carbonic acid. 
 
 2. Standard solution of hydrochloric acid, containing nearly or exactly 36' 5 grms. 
 HC1 (1 atom) in 1 litre. This may be prepared in several ways. 
 
 a. The most exact method is to determine the specific gravity of a sample of con- 
 centrated pure hydrochloric acid, deduce its strength by means of lire's table t (see 
 HYDROCHLORIC ACID, under CHLORINE), add the proper amount of water and determine 
 exactly the strength of the mixture by means of silver solution, as described in a pre- 
 ceding paragraph. 
 
 b. A concentrated acid, whose strength is approximately known from its specific 
 gravity, is so far diluted that it contains, as nearly as can be effected by this means, 
 20" 2 per cent, of HC1. If the liquid so obtained be quickly boiled in a narrow necked 
 flask, or in a retort in contact with platinum (not in an open basin), a time soon 
 arrives after which hydrochloric acid and water evaporate in the same proportion in 
 which they are contained in the residue. If about one half be evaporated we may be 
 certain that the point mentioned is attained. The percentage strength of the residue 
 depends upon the contemporary barometric pressure, according to the following table, 
 derived from experiments made on this subject bv Eoscoe and Dittmar. (Chem. Soc. 
 Qu. J. xii.) 
 
 Height of barometer in metres 
 
 073 
 
 074 
 
 0-75 
 
 0-76 
 
 0-77 
 
 0-78 
 
 0-79 
 
 Percentage strength of [ 
 residue in HC1 ^ ' 
 
 20-30 
 
 20-28 
 
 20-26 
 
 20-24 
 
 20-22 
 
 20-20 
 
 20-18 
 
 It will be seen that in cases where the barometer stands at about 0*76, the percentage 
 of HC1 may, without incurring great error, betaken as 20*24. 180"3 grms. of such an 
 acid are accordingly equivalent to 36'5 gr. of HC1. 
 
 c. Concentrated hydrochloric acid of known specific gravity is so far diluted with water 
 that it contains rather more than 36 -5 gr. HC1. In a measured quantity ( Fc.c.) of this 
 acid, carbonate of sodium is dissolved in the cold in the proportion of 53 milligrammes 
 to every 1 c.c. of the acid. A few grammes of sulphate of sodium are then added, 
 and the whole is boiled to expel the carbonic acid. The sulphate of sodium is added 
 to prevent the evolution of hydrochloric acid. 
 
 The liquid so prepared contains, besides the neutral salts, only the excess of acid 
 
 * Gay-Lussac's method of determining silver has recently been investigated by Mulder (see Mulder, 
 " Die Silberprobir-methode," etc., Leipzig bei Weber). He has made the singular observatiou, that a 
 mixture of exactly equivalent quantities of Ag and NaCl-solution gives precipitates wth both reagents. 
 Of either of the two solutions a quantity equivalent to z ^^ of the silver just precipitated is to be added, 
 before the formation of precipitates ceases. Stass ha~s, in the course of his determinations of atomic 
 weights, made a similar observation ; but according to him, the limits of the state of indifferent equi- 
 librium are narrower. These observations show that in order to attain the highest possible degree of 
 accuracy, a strictly empirical procedure must be adopted. 
 
 t For an acid whose strength is between twenty and thirty per cent, the relation between specific 
 gravity j, and percentage />, is given by the equation 
 
 p = 200 (s-l)-r- 0-3. 
 8 3 
 
262 ANALYSIS (VOLUMETRIC) 
 
 whose quantity has to be determined in order to find the strength of our test- acid. 
 For this purpose the mixture is coloured slightly red with solution of litmus, and 
 an arbitrarily diluted caustic soda solution is added while the liquid is hot, till the last 
 drop causes a decided blue colour (without mixture of violet). The quantity of 
 soda (t c.c.) required to produce the effect is noticed.* On the other hand, a fixed 
 volume (v) c.c. of the test-acid is measured, and in exactly the same manner, the 
 quantity (t l c.c.) of caustic soda required for its neutralisation is determined. 
 
 From the last test, we have found that 1 c.c. of the arbitrarily diluted soda is equi- 
 valent to r^- 1 of our acid. Hence we had previously added -j v c.c. more of this acid 
 than is necessary for the neutralisation of V. 53 miligrm. of carbonate of soda, i. e. 
 \V A) c.c. of test acid would have exactly sufficed to neutralise the weighed 
 quantity of carbonate of sodium. If, accordingly, we dilute f V ^\ c.c. of acid to 
 
 V c.c., then 1 c.c. of the mixture will contain exactly J. milligramme-atom of HC1. 
 In most cases, however, it is better not to perform this dilution, but to note that 1 c. c. 
 
 test-acid contains / -\ 3 6 '5 milligrammes of HC1. 
 
 I v - 71 / 
 
 3. Test Sulphuric acid. It is not necessary to have this as well as the hydrochloric 
 test-acid. Nevertheless it has over the latter the important advantage of being wholly 
 non-volatile when boiled in dilute solution. It can be prepared according to the 
 method described for hydrochloric acid under (c). 
 
 4. Test Caustic soda, which is, volume for volume, exactly or nearly equivalent to 
 the test-acid. Carbonate of sodium is rendered caustic in the ordinary manner, and 
 so far concentrated that the requisite strength is nearly attained. A small quantity 
 more of milk of lime is then added, the liquid allowed to cool (the air being excluded), 
 and the clear liquid drawn off by a syphon. For the exact determination of its strength, 
 60 c.c. test-acid are poured into a porcelain basin, a few drops of litmus are added, 
 and then the soda-solution is poured in from a burette till the colour begins to deepen. 
 A decided reaction is recovered by addition of 1 c.c, of test-acid ; about 2 grms. of 
 sulphate of soda are then added (if hydrochloric acid is being employed) ; the liquid is 
 heated to boiling, and soda is again poured in, till the liquid exhibits a distinct blue 
 colour. The calculation of the result requires no explanation. 
 
 5. Solution of Litmus. Powdered litmus is digested in the cold with twenty times 
 its weight of water, the solution filtered, and so exactly saturated, that 1 c.c. of 
 the litmus solution diluted with about 100 c.c. water, is turned decidedly red by ^ c.c. 
 of test-acid, and decidedly blue by the same quantity of test-alkali. 
 
 Acidimetry. Free acids in aqueous solutions, if these be free from magnesia, 
 alumina, and the heavy metals, and are not deeply coloured, may be determined in a 
 manner which will be sufficiently clear from paragraph 4. If hot solutions are used, 
 the caustic soda may without injury contain a little carbonic acid. But if we are 
 compelled to work in the cold, in consequence of the presence of salts of ammonia, or 
 because the acid to be determined cannot be prevented from evaporating by addition 
 of sulphate of sodium, caustic soda must be employed which is almost perfectly free 
 from carbonate. But even in such case, the termination of the reaction is not so easily 
 recognisable as when the solution is warm. It is best detected by dropping in the 
 soda rather quickly and without intermission, till the liquid, after stirring, remains 
 distinctly blue for some seconds. The gradual change of this colour to violet is no 
 evidence of the solution not being neutral. Such change depends upon the subsequent 
 action of carbonic acid upon the litmus. In the determination of weaker acids, 
 such as the organic, the same exactitude of reaction is not observed as occurs in the 
 determination of sulphuric, nitric, hydrochloric, and other strong acids. It must be 
 also noticed that many substances somewhat modify the blue colour which is the 
 criterion of completed reaction. In presence of many substances, such as ammoniacal 
 salts, &c., the change of colour from red to blue does not occur so quickly and decidedly 
 as when these substances are absent ; and in a few instances, as when acetic acid is pre- 
 sent, the real point of saturation is not reached until after the change of colour has taken 
 place. In order to render the analysis, in such cases as these, as accurate as possible, 
 it is advisable to make a control experiment under the same conditions as occur in the 
 real determination. Thus, for instance, if the strength of an acetic acid be required, 
 it will not be sufficient to make an analysis in the ordinary way, because the neutral, 
 acetates of sodium and potassium have an alkaline reaction, and this will mask the 
 true point of saturation ; it is best, therefore, to prepare a solution of acetic acid of 
 
 * The change of colour is best seen in a porcelain basin, or in a flak standing on white paper. 
 
OF LIQUIDS AND SOLIDS. 263 
 
 known strength by adding a known quantity of standard sulphuric acid to excess of 
 acetate of sodium, and to determine how much standard soda-solution is necessary 
 to bring about a definite change of colour in this acid solution. The strength of the 
 soda-solution being thus empirically determined with acetic acid, the real analysis 
 can be made without any reference to hypothesis. 
 
 Alkalimetry. Caustic alkalis and their carbonates are easily determined in a 
 manner which is so analogous to the method given (2, c.) for the preparation of standard 
 acid, that a fuller description is unnecessary. If many such determinations are to be 
 made, it is advisable to employ test-sulphuric (not hydrochloric) acid, and so to dilute 
 the soda that it saturates the test- acid, volume for volume. If ammonia is to be deter- 
 mined, the reneutralisation by soda must be performed in a perfectly cold solution. 
 
 Baryta, Strontia, and Lime, and their carbonates, are determined exactly as the 
 the fixed alkalis. But hydrochloric acid must be employed and no sulphate of sodium 
 can be added, otherwise sulphates of these earths are precipitated, and such preci- 
 pitates influence the litmus reaction. If only a small excess of acid has been used, the 
 quantity of hydrochloric acid lost by a boiling of short duration is very inconsiderable. 
 If this excess of acid does not occur in the first analysis, it may be made to do so in a 
 second one (see page 117). 
 
 3. ANALYSIS BY OXIDATION AND KEDTJCTION. It is known that most ele- 
 ments combine in various proportions with oxygen or its substituents ; that lower 
 oxides or chlorides are converted into higher oxides or chlorides, by the direct or in- 
 direct addition of oxygen or chlorine ; and that these higher compounds often give up 
 a portion of their oxygen or chlorine when in contact with reducing agents. Amongst 
 the innumerable reactions of this kind, all those can be employed which occur quickly, 
 and in which the termination of the reaction may be recognised with distinctness. 
 Amongst the numerous methods of volumetric analysis of this kind hitherto pro- 
 posed, we shall mention only the most important. These may be divided into 
 two classes : (a) those in which permanganic acid is the oxidant, (b) those in 
 which iodine acts as oxidant. 
 
 (a). With PERMANGANIC ACID : 
 
 1. Determination of Iron. If a solution of permanganate of potassium be added to 
 a strongly acid and dilute solution of a protosalt of iron, the Mn 2 4 K gives up f of 
 its oxygen to the iron, converting it into sesquisalt, and is itself converted into a 
 manganosum- and a potassium-salt of the acid added ; e. g. : 
 
 2Mn 2 4 K + 10S0 4 Fe 2 + 8S0 4 H 2 = 2S0 4 Mn 2 + S0 4 K 2 + 5(S0 4 ) 3 Fe 4 + 8H 2 0. 
 
 The deep purple red colour of the permanganic acid is continually destroyed as long 
 as any protoxide of iron is present ; but as soon as all the protoxide of iron is converted 
 into sesquioxide, the next drop of the reagent, even if the solution is very dilute, gives 
 a distinct rose-red coloration. Hence it is clear that protoxide of iron may be 
 determined by means of permanganate of potassium. A convenient standard solution 
 is obtained by dissolving about 8 grammes of the commercial crystallised salt in 1 litre 
 of water ; 1 c.c. of such solution oxidises, according to the relative purity of the salt, 
 from 12 14 milligrammes of iron present in the form of protoxide. On account of 
 this uncertainty, and because the solution gradually though slowly decomposes, a fresh 
 estimation of the strength of the solution must precede every series of iron deter- 
 minations. For this purpose, 0'5 grm. of pure iron (thin harpsichord wire is almost 
 perfectly pure) is dissolved in a great excess of pure dilute sulphuric acid, the air 
 being as far as possible excluded. Mohr recommends the double salt, S0 4 FeNH 4 + 
 3H Z 0, as a standard. The air-dry salt does not oxidise in air : it contains y of its 
 weight of iron. The solution is then allowed to cool, and is diluted with water free 
 from air to between 0'4 and 0'5 litres. Chameleon solution is added from a burette 
 to this liquid, till the colour of the last drop no longer disappears. From the result 
 it is easy to calculate how many milligrammes of iron are oxidised by 1 c.c. of the 
 chameleon solution. In order now to determine the quantity of iron in a given sub- 
 stance, so much of the substance as will contain about 0'5 gr. of iron is dissolved, if 
 possible, in water or sulphuric acid ; hydrochloric acid should be used only when it 
 cannot be avoided. If all the iron is dissolved as protoxide, the solution is diluted 
 to about 0-4 or 0'5 litres, and examined just as was done in the case of the standard 
 solution above described. If the iron is present partly or wholly as sesquioxide, this 
 must, previous to the dilution by boiling with zinc free from iron, be completely 
 reduced to the state of protoxide. The reduction may be considered complete when 
 the solution has become completely or nearly colourless. If any metals such as 
 arsenic, copper, &c. are hereby precipitated, they must be removed by quick filtration 
 through bibulous paper. 
 
 That the determination may be accurate, it is necessary 1. That the solution be 
 
 s 4 
 
264 ANALYSIS (VOLUMETRIC) 
 
 very dilute, in order that the yellow colour of the sesquioxide of iron formed may not 
 interfere with the distinctness of the reaction. If hydrochloric acid be present, more 
 water than usual must in general be added, because in concentrated solutions, hydro- 
 chloric acid reduces permanganic acid. 
 
 Mn 4 7 + 14HC1 = 7H 2 + 10C1 + 4MnCl 
 
 2. An excess of acid if possible, of sulphuric acid must be present. The object of 
 this is not only to make the colour of the sesquioxide of iron faint, but also to prevent 
 the oxygen of the air and the small quantity of air in the water used for the dilution, 
 from exerting an oxidising action during the operation. 
 
 It is scarcely necessary to mention that protoxide of iron may in this manner be 
 determined in the presence of sesquioxide. The principal advantage of this deter- 
 mination consists in the fact that the presence of many substances, which often greatly 
 complicated weight-analyses, does not interfere with its simplicity and accuracy. Even 
 the iron contained in ferrocyanides may be determined by means of permanganate of 
 potassium. 
 
 The behaviour of permanganic acid towards protoxide of iron may serve for the 
 indirect estimation of many substances which are capable of oxidising proto-salts of 
 iron. It is only necessary to allow the substance to act upon a known quantity of 
 iron in excess dissolved as protoxide, and to estimate the amount of protoxide unacted 
 upon, in the manner just described. Free chlorine, the active chlorine in chloride of 
 lime, the higher oxides of manganese *, nitric acid, &c., may be determined in this 
 way. We shall subsequently discuss other and better methods of estimating these 
 substances, and will not therefore here enter into further particulars. 
 
 2. Determination of Copper. The solution of the substance in water or nitric acid 
 is mixed 'with a quantity of tartrate of potassium and sodium sufficient to prevent 
 precipitation by the subsequent addition of an excess of caustic potash. The alkaline 
 liquid is heated to boiling, and milk-sugar is added, till all the copper is precipitated 
 as suboxide. This is collected on a filter, washed with hot water, and digested, 
 together with the filter, in strong hydrochloric acid and chloride of sodium. The 
 resulting solution of NaCl + Cu' 2 Cl, is to be diluted and treated with permanganate 
 of potassium, as in the determination of iron. The filter, if the operation be quickly 
 performed, has no action upon the permanganic acid. Since in this reaction, 4 atoms 
 of copper take up one atom of oxygen from the permanganic acid, every volume of 
 our solution will oxidise as many atoms of copper (31 '7 grms.), as it does of iron 
 (28 grms). 
 
 5Cu 4 + Mn 4 0' = lOCu'O + 2Mn'0 
 and lOFe'Q + Mn 4 7 = 5Fe 4 3 + 2Mn 2 0. 
 
 3. Determination of Oxalic acid. When oxalic acid and permanganic acid are 
 brought together in acid solutions, the former is oxidised to carbonic acid, the latter 
 reduced to protoxide of manganese, which unites with the acid present : 
 
 Mn'O 7 + 5C 2 H 2 4 + 2S0 4 H 2 = 10C0 2 + 2S0 4 Mn 2 + 7H 2 0. 
 
 Hence oxalic acid may be determined by means of permanganate of potassium in a dilute 
 solution containing an excess of free sulphuric acid, in a manner exactly similar to 
 that described under iron. For the determination of the permanganic acid, either pure, 
 air-dried, crystallised oxalic acid, C 2 H 2 4 + 2H 2 0, or pure iron, is employed. A volume 
 
 of test-solution which oxidises x atoms (x . 28) of iron, will convert - atoms of oxalic 
 
 acid (x : 31 -5) into carbonic acid and water. 
 
 The behaviour of permanganic acid towards oxalic acid may be employed for the 
 valuation of commercial peroxide of manganese : 1 grm. of the very finely powdered 
 peroxide is mixed with a weighed quantity (about 1-5 gramme) of crystallised oxalic 
 acid and a considerable excess of pure dilute sulphuric acid, and warmed till the 
 peroxide of manganese is decomposed. Water is added, the solution allowed to cool, 
 and the excess of oxalic acid determined as above : 1 atom of peroxide of manganese 
 transforms 1 atom of oxalic acid into carbonic acid : 
 
 Mn'O 2 + C 2 IF0 4 + S0 4 H 2 = S0 4 Mn 2 + 2C0 2 + 2H 2 0. 
 
 (6). METHODS IN WHICH IODINE ACTS AS OXIDISING AGENT. Iodine in 
 aqueous solution, in presence of oxidable substances, often acts upon the elements of 
 water so as to form hydriodic acid with its hydrogen, while the oxygen acts upon the 
 substance present. Now as the smallest quantity of free iodine may be recognised by its 
 property of blueing starch-solution, whereas hydriodic acid and the iodides are without 
 action upon starch, the substances mentioned may often be determined by mixing their 
 
 * The riotermination of nitric acid becomes exact only when the reaction takes place in an atmosphere 
 of hydrogen, but this precaution being taken, N*O S oxidises exactly 12Fe. (Freseuius.) 
 
OF LIQUIDS AND SOLIDS. 265 
 
 aqueous solutions with starch-solution, and then adding a standard solution of iodine 
 in iodide of potassium, until permanent blue coloration occurs. In order that this 
 reaction may succeed, the substance to be oxidised must, even in very dilute solution, 
 possess the property of decolorising the iodide of starch which has been locally 
 formed. For examples of determinations of this kind, we will take the following. 
 
 Hyposulphurous acid, as potassium-, or sodium-salt, in neutral or alkaline solutions 
 (made alkaline by bicarb on ates of the alkalis), acts upon iodine in such a manner 
 that tetrathionates of alkalis and metallic iodides are produced, e. g. \ 
 2S 2 3 Na 2 + 21 = 2NaI + S'O'Na 2 . 
 
 Arsenious acid, in the form of an alkali-salt, is converted by iodine into arsenic acid, 
 in a solution made distinctly alkaline by carbonate or bicarbonate of an alkali-metal. 
 Iodine must be added till the iodide of starch formed is no longer decolorised on the 
 addition of bicarbonate of sodium ; 4 atoms of iodine (508 pts.) oxidise 1 atom of 
 arsenious acid (198 pts.) : 
 
 As 2 + 41 + 2H 2 = 4HI + As 2 5 . 
 
 Sulphurous add, may be determined like hyposulphurous acid in solutions rendered 
 feebly alkaline by an alkaline carbonate. The product formed is sulphuric acid: 
 
 SO 2 + 21 + 2H 2 = 2HI + S0 4 H 2 . 
 
 If we endeavour to determine free sulphurous acid by iodine, very divergent results 
 are obtained when the solution is strong. _ In such cases, the quantity of sul- 
 phurous acid converted into sulphuric acid varies very much, according to the quantity 
 of water present and the rapidity with which the iodine is added. If, however, before 
 adding the iodine, the solution is so far diluted with water free from air, that less than , 
 0-4 grin, of sulphurous acid is contained in 1 litre of water, the reaction, 21 + 2H 2 + 
 SO 2 = 2HI + S0 4 H 2 , occurs with perfect regularity. 
 
 The circumstances under which this reaction takes place, were determined by 
 Bun sen (Ann. Ch. Pharm. Ixxxvi. 265), and applied to a series of very accurate volu- 
 metric determinations, the most important of which we shall here explain. 
 
 Analyses by means of Iodine and Sulphurous Acid. 
 
 Eeagents. 1. Pure iodide of potassium. 2. Pure hydrochloric acid. 3. Freshly 
 prepared, thin, very clear starch-solution.* A dilute solution of iodide of potassium, 
 mixed with starch and hydrochloric acid, must give a mixture which remains colourless 
 for several minutes. 
 
 4. A standard solution of iodine in iodide of potassium, 5 grms. of commercial 
 iodine, and 10 to 12 grms. of iodide of potassium, are dissolved in about 20 c.c. water, 
 and as soon as all the iodine is dissolved the solution is diluted to 1 litre. 
 
 5. A solution of sulphurous acid in distilled water. This must be so diluted that 
 about 10 volumes of it are necessary to decolorise 1 volume of the iodine-solution (4). 
 This solution should be prepared in quantities of 10 to 20 litres, and allowed to stand 
 about an hour excluded from the air, before use, so that the oxygen contained in the 
 dissolved air may be absorbed by the sulphurous acid. It may be advantageously 
 kept in an earthenware vessel, provided with a tap at the bottom, and a fine drawn 
 out tube above to allow the air to enter. The strength of such a solution may be 
 considered as constant during the performance of one analysis. 
 
 The first question is to determine exactly the strength of the iodine-solution, already 
 approximately known. If we had a small quantity of perfectly pure iodine of known 
 weight, this might be easily done by comparing such iodine with the standard-solution 
 by means of the same sulphurous acid. Such a quantity of iodine to serve as a 
 measure, is obtained by boiling between 200 and 400 milligrammes ( = A) of pure 
 anhydrous bichromate of potassium with fuming hydrochloric acid, and collecting the 
 evolved chlorine in a solution of iodide of potassium (for one part of the bichromate 
 about 20 parts iodide of potassium are employed). 1 atom ( 294 % 8) of bichromate 
 liberates under these circumstances 6 atoms of iodine (6 x 127'0): 
 
 Cr 4 K 2 7 + 14HC1 = 7IFO + 2KC1 + 2Cr 2 Cl s + 6C1 
 6C1 + 6KI = 6KC1 + 61 
 
 In order to perform this operation without loss, the following method is adopted. 
 
 On a glass tube of about 4 5 mm. internal diameter, a bulb of about 30 c.c. capacity 
 is blown, and a flask is thus obtained of the form shown in fig. 48. To a short piece 
 of the same tubing, a longer and narrower tube is fused, drawn out at d, and bent as 
 shown in the figure. If the neck of the flask and the adapter-tube be ground flat and 
 connected with caoutchouc, in such a manner as to bring them close together, an appa- 
 
 Starch-solution, when filtered and saturated with chloride of sodium, may be kept a long time with- 
 out decomposition. (Mohr.) 
 
266 
 
 ANALYSIS (VOLUMETRIC) 
 
 Fig. 48. 
 
 ratus is obtained for the evolution of chlorine, which is scarcely inferior to one con- 
 sisting wholly of glass. The caoutchouc tube before use must be freed from adhering 
 sulphur by boiling with very dilute caustic soda and thorough washing with water. 
 
 A retort of about 150 c.c. capacity (fig. 49) serves to hold the solution of iodide of 
 potassium. The neck of the retort is widened at a, to receive any solution driven 
 back by the expelled air. In order to make the determination, we bring the bi- 
 chromate of potassium into the flask, which is then filled to | with fuming hydro- 
 chloric acid ; the delivery-tube is attached, and placed so far in the retort (filled up 
 to the commencement of the neck with iodide of potassium solution), that the chlorine 
 which is not immediately absorbed must collect at b. The flask is first gently heated 
 till the decomposition is complete, then more strongly, in order to drive over every 
 trace of chlorine into the iodide of potassium solution by means of the gaseous water 
 and hydrochloric acid. The retrogression of the iodide can scarcely take place if 
 some care is taken, because it can only occur very slowly, in consequence of the small 
 volume of the apparatus and the fineness of the point d. After the hydrochloric acid 
 vapours have been evolved for about five minutes, it may be assumed that all the 
 chlorine is expelled. Without discontinuing the boiling, the delivery-tube is with- 
 drawn from the retort, and the vapours are conducted into some fresh solution of 
 iodide of potassium, the boiling being continued for a few moments longer. If this 
 solution remains uncoloured, the operation may be regarded as successful. 
 
 The contents of the retort (coloured deep brown by iodine) are quickly cooled, and 
 poured out into a beaker glass, and portions of 400 to 450 c.c. of the dilute sulphurous 
 
 acid are successively added, without 
 loss of time, until the liquid is 
 colourless. The measurement of the 
 sulphurous acid is effected in a flask 
 which contains, up to a mark on its 
 narrow neck, from 400 to 450 c.c., 
 but whose capacity need not be ac- 
 curately known. The flask is rinsed 
 out with the sulphurous acid, filled 
 up to the mark, and emptied in a 
 definite manner, which should be 
 strictly adhered to during the same 
 analysis. Direct experiments have 
 shown that the volume of the liquid 
 delivered is sufficiently constant. 
 
 The liquid decolorised by sul- 
 phurous acid contains an excess of 
 this body. Starch and then normal 
 iodine-solution are therefore added 
 till blue coloration occurs. Let the 
 volume of the latter necessary for 
 this be t } c.c. Immediately after- 
 wards, one of the measures of sul- 
 phurous acid previously employed is 
 taken, and the volume (t c.c.) of 
 standard iodine-solution determined 
 
 which is necessary for its oxidation. If, then, the number n of the flasks of sul- 
 phurous acid which were added to the iodide of potassium solution from the retort 
 has been noted, the strength of the normal solution may be easily calculated. 
 
 Let us call, for brevity, the contents of the flask the " volume." From the result 
 of the determination just given, we find that nt c.c. normal iodine-solution were 
 necessary for the oxidation of n volumes sulphurous acid. For such oxidation, t 1 c.c. 
 of the same iodine-solution, together with the quantity of iodine produced by the 
 distillation of A milligrammes of bichromate of potassium with hydrochloric acid, were 
 
 also sufficient. This amount of iodine (A. ] millg. is therefore equivalent 
 
 to (nt t 1 ) c.c. of iodine solution. Hence 1 c.c. of the latter contains 
 
 A x 3 x 127 
 147-4 ( t - t } \ mi ^ 1 S rammes Of free iodine, or 
 
 A x 3 
 147-4 (nt t 1 ) = ^ mil % ramme - atoms of f ree io<line. 
 
 Inasmuch as all subsequent analyses depend upon these determinations, the latter 
 must be performed two or three times, and the mean taken of the results (which should 
 
 Fig. 49. 
 
OF LIQUIDS AND SOLIDS. 267 
 
 nearly agree). The most various analyses may be performed by means of an exactly 
 determined iodine-solution. We will take the following examples. 
 
 1. The determination of sulphurous, hyposulphurous, and arsenious acids has been 
 already described. 
 
 2. Sulphuretted hydrogen may be determined similarly to sulphurous acid, in a 
 solution containing less than 0'4 grm. in 1 litre; but from some unexplained cause the 
 results are only approximately exact. The reaction which here occurs is represented 
 by the equation: IPS + 21 = 2HI + S. 
 
 3. Determination of free Iodine, Bromine, and Chlorine. Iodine dissolves directly in 
 a solution of iodide of potassium ; bromine and chlorine form bromides and chlorides, 
 liberating an equivalent of iodine. The quantity of the latter is determined by adding 
 excess of sulphurous acid (n volumes), then starch, and finally solution of iodine (t l c.c.), 
 until the well-known reaction occurs. If now t c.c. of iodine solution were necessary 
 for the oxidation of 1 volume of sulphurous acid, the liberated iodine must be equi- 
 valent to nt t l of iodine-solution, or the chlorine, bromine, or iodine must have the 
 value of (nt t 1 ) T milligramme-atoms. 
 
 4. Determination of the Oxides of Chlorine which contain less than five atoms of 
 Oxygen for two atoms of Chlorine. All these substances are decomposed by iodide 
 of potassium and hydrochloric acid in the following way : 
 
 CPO* 
 
 The free iodine is determined according to (3). Commercial bleaching powders are 
 tested for the amount of active chlorine which they contain, by treating them with an 
 excess of iodide of potassium and enough hydrochloric acid to cause a slightly acid 
 reaction. Each atom of active chlorine liberates an atom of iodine : 
 
 CaCIO + CaCl + 2HC1 + 2KI = 2CaCl + H*0 + 2KC1 + 21. 
 
 5. Chlorates. According to Bunsen's experiments, these salts when distilled with 
 hydrochloric acid do not give up free oxygen, but only free chlorine and lower oxides 
 of chlorine. If the products of distillation be received in excess of iodide of potas- 
 sium, the final result is the liberation of 61 for C10 3 H. Such iodine may be deter- 
 mined according to (3).* 
 
 6. lodates. One atom of free iodic acid decomposes with 5 atoms of hydriodic acid 
 to 3 atoms of water and 6 atoms of free iodine (HIO 3 + 5HI = 61 + 3H 2 0). 
 This reaction may serve for the determination of iodic acid. On the other hand, 
 pure iodate of potassium may be conveniently employed for determining the strength 
 of the normal iodine-solution. (B un s e n.) 
 
 7. Metallic oxides containing a portion of their oxygen in such a state that it liberates 
 an equivalent quantity of chlorine on boiling with strong hydrochloric acid, may be 
 determined by boiling them with fuming hydrochloric acid, collecting the chlorine in 
 iodide of potassium, and determining the iodine set free according to (3). To this 
 class belong all peroxides, the higher oxides of manganese, chromic acid, and other 
 metallic acids, &c. &c. In analysing manganic oxides, a weak hydrochloric acid of 
 about 20 per cent, must (exceptionally) be employed, because on using fuming hydro- 
 chloric acid, chlorine is apt to escape. The calculation scarcely needs any explanation. 
 The amount of free chlorine, if we retain the usual symbols, amounts to (nt t l )T 
 milligramme-atoms. Half this number of atoms of active oxygen are therefore 
 present, and these stand in a known simple numerical relation to the number of atoms 
 of the substance to be determined. 
 
 8. Metallic oxides which may be peroxidised by chlorine, are determined by boiling 
 them with a weighed excess of bichromate of potassium and hydrochloric acid, receiving 
 the excess of chlorine in iodide of potassium solution, and determining it according 
 to (3). As an example of the calculation, let us take the determination of protoxide 
 of iron. Let the amount of bichromate of potassium employed be A milligrammes ; 
 
 this (- milligramme-atoms), if iron had been absent, would have liberated '- 
 
 milligramme-atoms of free iodine. If instead of this, we actually find only (nt tf 1 ) T 
 milligramme-atoms, then : 
 
 milligramme-atoms of chlorine must have served for the oxidation of the iron. Or : 
 
 x 28 
 
 milligrammes of iron must have been present. 
 
 * If perchloric acid were produced in this reaction (and its entire absence has not yet been proved ), the 
 method, as applied to chlorates, would not give accurate results. Bunsen, in his Memoir, gives only 
 one determination of chlorate of potassium, which, however, agrees very well with theory. 
 
268 ANALYSIS (VOLUMETRIC) 
 
 Having become acquainted with the most important volumetric methods we may 
 now consider a point in connection with the calculation of the results. If a long series 
 of determinations of the same kind have to be performed successively, the time neces- 
 sary for their calculation is of great consequence, and it is important to consider the 
 best way of simplifying it as much as possible. This may generally be effected by so 
 choosing arbitrary magnitudes which occur in the calculation, as the weight of the 
 substance, the strength of the normal solution, &c., that the mathematical expression for 
 the result may be as simple as possible. The following examples will illustrate this : 
 
 1. A number of soda determinations have to be made with an acid which contains 
 1*017 milligramme-atoms of sulphuric acid (S0 4 H* = 98) in 1 c.c. If a milligrammes 
 of soda be employed in the analysis, and if the volume of the acid used in neutralisation 
 
 , . ^ . * x 1-017 x 62 x 100 
 
 be Jc c.c. then the soda contains per cent, of anhydrous 
 
 soda (Na'O). If now 1-017 x 62 x 100 milligrammes of soda be weighed each time, 
 
 A.I. ^ j> * 1'017 x 62 x 100 . 
 
 then the fraction is = 1, and the percentage of the soda in caustic 
 
 soda is =3 k, that is, simply equal to the number of c.c. of the standard acid used. 
 
 2. In the previous division (8), we have considered the determination of iron by 
 means of iodine-solution and sulphurous acid. . If milligramme of the iron compound 
 be employed for the analysis, the percentage (x) of iron is derived from the formula 
 
 2 x 28 x 100 
 
 in which the letters have the signification before given. It is clear that the calculation 
 is considerably simplified if (1) T be a round fractional number, for instance, i, 
 (2) if A be made a simple multiple of 147-4, for instance, 5 x 147 '4 milligrammes. 
 (3). By taking e so as to be a simple submultiple of 2 x 28 x 100, for instance, 
 30 x 28 milligrammes. W. D. 
 
 ANALYSIS (VOX.UIWCETRIC) of GASES. This branch of analysis has 
 of late attracted much attention from chemists ; but the chief improvements and de- 
 velopments relating to it are due to Professor Bunsen. Previous to his researches 
 on the subject, the processes adopted for measuring and analysing gases were so ex- 
 ceedingly imperfect, the inaccuracies introduced so numerous, and even the reagents 
 made use of so defective, that only the most variable results could be obtained ; now, 
 on the contrary, gases may be analysed with an accuracy which cannot be equalled 
 in any other branch of chemistry. So far indeed as accuracy and simplicity of mani- 
 pulation are concerned, Bunsen' s method leaves little to be desired; but it is long and 
 tedious, even a simple analysis requiring some days for completion. The necessary 
 calculations for the reduction and correction of the observations are also numerous and 
 require considerable time and attention.* To obviate these inconveniences, several 
 methods have of late been proposed, by which the composition of a gas may be accu- 
 rately determined in a very much shorter time, and without the calculations formerly 
 necessary. 
 
 The arrangement of the subject adopted in this article is : first a description of the 
 apparatus and general method proposed by Bunsen ; then that of the more recent and 
 expeditious methods ; and lastly, the processes, which to a certain extent are common 
 to all the methods, for separating and estimating the different gases. 
 
 According to the method of Professor Bunsen, the gases are collected and measured 
 in graduated tubes over mercury. For this purpose, two straight glass tubes are used ; 
 one of them, which should be about 250 mm. long and 20 mm. in diameter, is termed the 
 absorption-tube, and the other which is from 500 to 600mm. long, and 20 mm. in 
 diameter, is termed the eudiometer (figs. 50, 51). The absorption-tube is pro- 
 vided with a sort of lip as shown in the figure, to enable the operator to pass the gas 
 easily out of this tube into the eudiometer. As this latter tube is the one in which the 
 combustible gases are exploded, two platinum wires must be fused into the closed end 
 of it, for the passage of the electric spark. This is done by strongly heating the end of 
 the tube in the blowpipe lamp, and then just touching it at the point where the wire is 
 to be introduced, with a hot platinum wire ; to this the glass strongly adheres, and by 
 this means is drawn out to a fine thread, which, on being cut off close to the eudiometer, 
 is found to be hollow ; through this hole a platinum wire is introduced, and the glass 
 carefully fused all round it. A second platinum wire is then by similar means fused into 
 the opposite side of the eudiometer. These wires should not project straight across the 
 tube, as they are then apt to become bent and moved from their proper distance 
 
 * For a more detailed account of Bunsen's method of analysis, and for further information on 
 gasometry in general, we would refer the reader to Buust-u's " Gasometry," translated by Roscoe. 
 ( Walton and Maberly.) 
 
OF GASES. 
 
 269 
 
 Fig. 51. 
 
 f\ 
 
 -= 
 
 I 
 
 apart on filling the tube with mercury ; if straight, they would also prevent the 
 eudiometer from being properly cleaned : it is consequently most convenient to have 
 them bent so as to lie against the rounded top of the eudiometer. The ends of the 
 wires should be at the distance apart of about 1 to 2 m.m. In order to ascertain 
 whether the wires have been properly fused in, so that the con- 
 tact of the platinum and glass may be perfect and no probability Fig. 50. 
 of leakage can occur, the eudiometer is filled and inverted in a 
 mercury trough, and then, while held in a vertical position, sharply 
 rapped against the bottom of the trough ; this communicates a move- 
 ment to the mercury in the tube, which sinking for a moment leaves 
 a vacuum at the top, whereupon if the wires are not fu ed in abso- 
 lutely air-tight, a row of small bubbles will be seen rising from the 
 defective point. 
 
 Having proved the tube to be air-tight, the next operation is to 
 etch, by means of hydrofluoric acid, a millimetre scale on it and 
 on the absorption-tube. This may easily be done by the following 
 process, which was also suggested by Professor Bunsen. The tube 
 to be etched is heated up to the temperature at which bees-wax 
 melts over a fire, being held by means of a stick which passes 
 through a cork fitted into the open end of it. The tube is then 
 covered as uniformly as possible with melted wax, which is best 
 done by painting it all over with wax, by means of a brush 
 or feather. During the cooling, it should be continually turned 
 round in the hand, so as to keep the wax equally distributed over the 
 whole surface. If the tube when cold is found to be completely 
 covered with wax, it is then ready for etching. 
 
 Fig. 52 represents the apparatus used for this purpose, A B is a 
 table or large board, with a groove running along it of such size 
 that the tube to be graduated will lie easily in it ; d d represents 
 this tube, which is firmly held in its place by two brass plates e e, 
 screwed down upon it. At the other end of the groove, a standard 
 tube b b, is also firmly fixed by means of a brass plate, and on this 
 tube is the scale which is to be exactly copied on the wax covering 
 the tube d d. This is done by means of a long bar of wood, to one 
 end of which is fixed a steel point, and to the other a kind of knife. 
 The rod is held by the ends as shown in the figure, the right hand 
 guiding the knife. In using the apparatus, the steel point is 
 allowed to fall into one of the divisions on the standard tube, 
 which are purposely deeply etched, and while it is held there, a cut is made by means 
 of the knife on the wax covering the tube. The length of this cut, and the consequent 
 breadth of the scale, is regulated by the distance between the two brass plates e e. 
 As soon as this first stroke has been made, the wooden rod is gently moved a 
 
 Fig. 52. 
 
 little forwards until the point falls into the next mark on the standard tube ; then 
 a second cut is made in the wax, and so on. The steel point should always rest 
 against the brass plate c c, which will then serve to keep it in the same straight line. 
 In order to render the reading of the scale more easy, it is convenient to have every 
 fifth stroke on it longer than the others ; which is easily accomplished by having slits 
 made in the brass plate e, at the distance of 5 mm. apart, so that when the knife 
 arrives at one of these slits, it passes further across the tube than in other cases. 
 Before removing the waxed tube, it must be carefully examined, and if any false strokes 
 are seen, they may be removed by applying a thin heated wire to the spot : then, 
 when the wax has cooled, a fresh stroke may be made. The tube is now removed, and 
 at each centimetre, the figures indicating the number of millimetres from the top are 
 scratched in the wax by means of a needle. If any of the wax has been removed from 
 the tube by the pressure of the brass plates, these places must be carefully re-covered, 
 and the tube is then ready to be exposed to the hydrofluoric acid. 
 
270 
 
 ANALYSIS (VOLUMETRIC) 
 
 Fig. 53. 
 
 This is most conveniently done in a kind of long narrow leaden dish. Powdered 
 fluor-spar is strewed along the bottom, and a large excess of sulphuric acid added ; 
 heat may then be applied. As soon as the gas comes off abundantly, the lamp is 
 removed, the tube laid over the dish resting on two wire supports, and the whole is 
 covered with a sheet of paper. When the tube has remained there about three minutes 
 it should be removed and one of the divisions examined by passing the nail over it, 
 to ascertain to what extent the etching has taken place. In from three to six minutes, 
 most tubes will be sufficiently acted on. The etching may also be accomplished with- 
 out applying heat to the hydrofluoric mixture ; in this, case the tube must be left in 
 contact with the acid for several hours. This latter method yields perhaps the most 
 distinct graduation. In order to render the scale still more clear, it should be rubbed 
 over with a mixture of vermilion and copal varnish, which fills and hardens in each of 
 the divisions, rendering them very evident to the eye. 
 
 Since no tube is of precisely the same diameter for any length together, the scale 
 thus etched bears evidently no constant relation to the cubic capacity of the tube. 
 In order then to ascertain to what extent the capacity varies in different parts of tube 
 equal volumes of mercury must be poured into it, and the space they occupy read off 
 on the scale. Fig. 53 represents a convenient form of apparatus for always obtaining, 
 
 these equal volumes of mercury, a is a small glass 
 tube fixed in a handle and capable of containing 
 about that amount of mercury which is required to 
 fill the eudiometer through 20 mm. of its length. 
 c is a glass plate, on the top of which the two ends 
 of a strip of caoutchouc are fastened by sealing wax, 
 so as to form a loop which is slipped over the 
 thumb. By turning the stopcock, which allows the 
 mercury to flow from the reservoir b, the glass 
 measure, the top of which must be ground perfectly 
 even, is completely filled, and the mercury rises 
 in a curve above the top ; on depressing the plate c, 
 the excess is expelled and the tube obtained per- 
 fectly full: care must, however, be taken that no 
 bubbles of air remain adhering to the sides. In 
 filling the measure, it is well to allow the end of 
 the tube e to rest on the bottom of it, and only 
 gradually to withdraw it when nearly full of mer- 
 cury. The tube to be calibrated is firmly held in 
 a perpendicular position by means of a clamp, and 
 the measures of mercury are then carefully poured 
 in, any bubbles of air which may remain adhering 
 to the tube, being removed by means of a small stick 
 or piece of whalebone. After each addition of 
 mercury, the height which it occupies on the scale is 
 read off. In order to prevent errors from parallax, 
 this should be done by means of a telescope fastened 
 to a clamp which moves on a perpendicular support. 
 In all readings-off, it is the position of the highest 
 part of the mercury meniscus on the scale that is observed. This process for deter- 
 mining the cubic capacity of the tube should always be gone through twice, and the 
 mean of the two series of observation taken as the basis of calculation. An example 
 will best show how these calculations are made and the results tabulated. The height 
 of the mercury in the tube after the successive additions of the measured quantity is, 
 
 diff. 
 9-1 
 
 23-0 
 
 36-6 
 
 50-15 
 
 - 13-9 
 
 - 13-6 
 
 - 13-55 
 
 In the second column is expressed the height which this constant quantity of mer- 
 cury occupied. This varies of course with the capacity of the tube, increasing as the 
 tube diminishes, and diminishing as the tube increases in size. One of these differences, 
 generally the largest, is taken as the standard, say 13 -9, that is, 13 '9 volumes of mer- 
 cury have been found to occupy on the scale : 
 
 mm. 
 
 1 x 13-9 - 9-1 
 
 2 x 13-9 - 23-0 
 
 3 x 13-9 - 36-6 
 
 4 x 13-9 - 50-15 
 
OF GASES. 
 
 271 
 
 This gives the relative values of the scale at these particular points, and it only 
 remains to interpolate the respective values of each division between these successive 
 points. In the first instance, between 9'1 and 23 '0, each millimetre will represent 
 exactly 1 volume of mercury ; but in the second instance, where the 13"9 vols. of mer- 
 cury occupy only a length of 13 '6 mm. where the tube in fact is broader, each division 
 
 I O.Q 
 
 will have a value equal to = 1-022, and this number represents the capacity of 
 
 13'6 
 each millimetre between 23*0 and 36'6. Again the capacity of each division between 
 
 1 ^*Q 
 36-6 and 50'15 is 4 ^ = 1'025. In this way is formed a table, which, although 
 
 13"5o 
 
 perfectly arbitrary, is relatively correct, the amount of error arising from the alteration 
 of the size of the tube between each reading-off of the height of the mercury, being 
 quite inappreciable, when the measured quantity does not extend over more than 
 about 20 mm. The following table is calculated from the foregoing observations. 
 In the first column, the divisions on the scale are given, in the second their arbitrary 
 value. 
 
 9 
 
 13-80 
 
 24 
 
 28-82 
 
 39 
 
 44-17 
 
 10 
 
 14-80 
 
 25 
 
 29-84 
 
 40 
 
 45-20 
 
 11 
 
 15-80 
 
 26 
 
 30-86 
 
 41 
 
 46-23 
 
 12 
 
 16-80 
 
 27 
 
 31-88 
 
 42 
 
 47-25 
 
 13 
 
 17-80 
 
 28 
 
 32-91 
 
 43 
 
 48-28 
 
 14 
 
 18-80 
 
 29 
 
 33-93 
 
 44 
 
 49-30 
 
 15 
 
 19-80 
 
 30 
 
 34-95 
 
 45 
 
 50-33 
 
 16 
 
 20-80 
 
 31 
 
 35-97 
 
 46 
 
 51-36 
 
 17 
 
 21-80 
 
 32 
 
 36-99 
 
 47 
 48 
 
 52-38 
 
 18 
 
 22-80 
 
 33 
 
 38-02 
 
 63-41 
 
 19 
 
 23-80 
 
 34 
 
 39-04 
 
 49 
 
 51-43 
 
 20 
 
 24-80 
 
 35 
 36 
 
 40-06 
 
 50 
 
 55-45 
 
 21 
 
 25-80 
 
 41-10 
 
 51 
 
 
 22 
 
 26-80 
 
 37 
 
 42-12 
 
 52 
 
 
 23 
 
 27-80 
 
 38 
 
 43-15 
 
 53 
 
 
 As it is always the highest point of the meniscus of the mercury that is read off 
 on the scale, both in calibrating the tube and afterwards in measuring the amount of 
 gas it may contain, a slight correction must be applied to every observation to correct 
 the error which would otherwise arise from the convexity of the mercury. By re- 
 ferring to fig. 54, it will easily be seen how this error arises. (1) In calibrating the 
 tube : if a o a' represent the meniscus, it is the number on the scale coinciding with the 
 line c c', that is read off, although the tube is not full up to that point by the space 
 a c c' a ; and (2), in analysing a gas, when the tube is in the reverse position, the same 
 number on the scale would be read off, although the meniscus of the mercury only 
 coincided with the curve n o n', leaving in fact a space as much below c c' unoccupied 
 by mercury in this instance, as was left above it in the former one. Hence after re- 
 ferring to the table to ascertain the relative value of any reading-off, there must be 
 added to it a quantity equal to the whole space ana' n. What this number is, which 
 has always to be added can easily be ascertained by the following process. The 
 eudiometer being fixed in a perpendicular position with its closed end downwards, a 
 
272 
 
 ANALYSIS (VOLUMETRIC) 
 
 small quantity of mercury is poured into the tube, and its height carefully noted ; 
 a few drops of a dilute solution of corrosive sublimate are now added, the effect of 
 which is entirely to destroy the meniscus, and render the surface of the mercury 
 
 Fij. 54. 
 
 perfectly flat : the height ##' at which it now stands in the tube is read off. Twice the 
 
 difference of these two readings is then the quantity to be added to each observation 
 
 after referring to the table of capacities. 
 
 The most convenient form of mercury-trough is that proposed by Bunsen, and 
 
 represented in fig. 55. It is about 350 mm. long, and 80 mm. broad. The two sides 
 
 c c, are made of thick glass plates, and the lower part of it A, is formed out of a single 
 piece of wood hollowed out. In order to economise the amount of mercury 
 
 Fig. 56. necessary, the inside of the trough is made round at the bottom instead of 
 being square. G forms a convenient support for the eudiometer. Before 
 using the trough, it should be well rubbed with corrosive sublimate and 
 mercury, or else small bubbles of air are apt to remain adhering to the wood, 
 and may afterwards rise into the eudiometer. 
 
 A good thermometer and barometer are of course indispensable. The 
 length of the degrees on the thermometer scale should be such that the 
 position of the mercury, to a tenth of a degree centigrade, may be easily 
 read off by means of the telescope. The barometer generally used is of 
 the syphon form (fig. 56). The scale is etched on the glass and the 
 closed end is bent as shown in the figure, so that the scale on the two limbs 
 is in the same straight line. The thermometer t, is placed in the open 
 end of the barometer, and held in its place by a small piece of whalebone, 
 which acts as a spring. Before reading off the height of the barometer and 
 thermometer, the latter should be gently moved a little up and down, thus 
 communicating to the mercury in the barometer a slight movement, which 
 overcomes any adhesion between the mercury and the glass. 
 
 The kind of room which is used as a gas-laboratory when this process 
 is adopted, is a point of very considerable importance. It should have a 
 northerly aspect, and the walls should be thick ; in fact, the room must be 
 protected in every way from sudden changes of temperature. The mercury 
 trough and barometer should stand on a table immediately in front of a 
 window, if possible a double one. The table is provided with a rim round 
 it, in order to prevent the loss of any mercury that may happen to be spilt 
 upon it. Between every two operations in the analysis, at least half an hour 
 must be allowed to elapse, in order that all parts of the apparatus may return to 
 the temperature of the room. Great care must be taken in filling the eu- 
 diometer and absorption-tube with mercury, that no air remains adhering to 
 the sides of the tube. This is most easily avoided by introducing the mercury 
 through a funnel, to which is attached a narrow glass tube reaching very 
 
 nearly to the top of the eudiometer ; the mercury then rises gradually, the funnel being 
 
ANALYSIS (VOLUMETRIC) OF GASES. 
 
 273 
 
 Fig. 57. 
 
 kept full, and expels the air very thoroughly from the tube. A small bubble of air 
 will however generally be found to remain in contact with the platinum wires in the 
 eudiometer ; this must be got rid of by placing the thumb over the open end of the 
 tube, and holding it in an inclined position ; then, by means of a sudden jerk, the 
 bubble may be detached from the wires, and by merely inverting the eudiometer, 
 allowed to escape. 
 
 All the readings-off, as before stated, are made with the help of a telescope, which 
 should be at a distance of seven or eight feet from the tubes. Care should always be 
 taken that the division to be read off is nearly in the middle of the field of the tele- 
 scope, or a slight error may arise from parallax. It is therefore convenient to have 
 the telescope provided with a cross wire. 
 
 At each stage of the analysis, four observations have to be made : 1st, the height 
 of the mercury in the gas-tube ; 2nd, the height of the mercury in the trough as 
 measured on the scale of the gas-tube ; 3rd, the tempera- 
 ture ; and 4th, the atmospheric pressure. The barometer 
 and thermometer are always read off last ; for before doing 
 this, it is necessary to approach the table in order to move 
 the thermometer, as before described, and the heat given 
 out from the body would increase the volume of gas in the 
 tube. In order to read off accurately the level of the 
 mercury in the trough, it is necessary so to place a piece 
 of white paper between the glass side of the trough and 
 the tube, that it may reflect the light from the window on 
 to the scale. Fig. 57 shows how this is conveniently ar- 
 ranged, the scale being seen through the slit m. 
 
 After each operation in the analysis, before leaving the 
 tubes to cool, a rapid observation should be made with 
 the telescope, in order to see that the scale on the eudio- 
 meter is in its right position, passing apparently exactly 
 through the highest point of the meniscus, and also that 
 the height of the mercury both in and outside the tube 
 can be easily read off. 
 
 In order to render the observations thus made at different 
 temperatures and pressures comparable, they must be re- 
 duced to a common standard, the one generally employed being dry air at C., and 
 under a pressure of 1 metre of mercury. If v represent the volume of gas as taken 
 from the table, m the error of the meniscus, b the height of the mercury in the gas- 
 tube above that in the trough, t the temperature, and B the height of the barometer, 
 the following formula will give the corrected volume V\ under the standard tempe- 
 
 There is also another point which must not be overlooked in the calculation, viz. the 
 effect of the tension of water- vapour. If the gas is saturated with moisture, and the 
 temperature at which the observation of its volume was made is known, it is then 
 only necessary to refer to the table of tensions of aqueous vapour and extract the 
 number corresponding to that temperature : this must be deducted from the height of 
 the barometer. Thus, the formula for the reduction of gases saturated with aqueous 
 
 vapour is - - - - ^ - = V, where T is the tension of aqueous vapour 
 ' J 
 
 for the temperature t. To ensure a gas being completely saturated with moisture, a 
 drop of water is always introduced into the eudiometer before filling it with mercury. 
 In order to show more clearly how these calculations are made, the following ex- 
 ample taken from Bunsen's Gasometry, is cited, of the measurement of the same 
 quantity of air, first saturated with moisture and afterwards dry. 
 
 Observation at the lower level of the mercury . 
 Observation at the upper level in the eudiometer 
 Height of the column b to be subtracted from 
 
 barometer 
 
 The divisions 317'3 and 3107 correspond to the 
 
 volumes in the table of capacity . 
 Correction for the meniscus .... 
 
 Temperature of the air 
 
 Height of the barometer ..... 
 Tension of aqueous vapour for 20*2 C. 
 
 VOL. I. T 
 
 Moist. 
 565-9 mm. 
 317-3 
 
 248-6 
 
 V . 292-7 
 
 0-4 
 
 20-2 C. 
 0-7469 m. 
 0-0176 m. 
 
 Dry. 
 
 565-9 mm. 
 310-7 
 
 255-2 
 
 286-0 
 0-4 
 
 20-2 C. 
 0-7474 m. 
 
274 
 
 ANALYSIS (VOLUMETRIC) OF GASES. 
 
 log.(F + m) = log. 293-1 = 2-46702 
 
 + log. (B - b - T) = log. -4807 = 0-68187 - i 
 
 + compl. log. (1 + 0-00366)5) = compl. log. 1-0739 = Q-96903 - 1 
 
 log. V 2-11792 
 
 V 131-20. 
 
 For the dry air we have : 
 
 log. (V + m) - log. 286-4 = 2-45697 
 
 + log. (B b) = log. 0-4922 = 0-69214 - 1 
 
 + compl. log. (1 + 0-00366*) = compl. log. 1-0739 = Q-969Q3 - 1 
 
 log. V 2-11814 
 
 V = 131-26. 
 
 A modification of Bunsen's method has been proposed by Messrs. Williamson 
 and Kussell (Proceedings of the Eoyal Society, vol. ix. p. 218), whereby the effect 
 of any alteration in the barometer or thermometer on the gas during the analysis 
 is entirely eliminated : moreover, the gas operated on is always read off saturated 
 with aqueous vapour, so that no calculations are necessary for reducing the 
 volume to a standard temperature and pressure. The principle on which this simpli- 
 fication depends is, that of always retaining the gas at the same degree of elas- 
 ticity. If, for instance, a fall of temperature has occurred, then by diminishing the 
 pressure on the gas a certain amount, its elasticity will remain unaltered ; and for a 
 rise in temperature, the pressure must be correspondingly increased to retain the gas 
 at the same volume. This equally applies to any alteration in the barometer. The 
 means adopted for ascertaining exactly how much the pressure on the gas has to be 
 increased or diminished for any variations of the barometer or thermometer, is simply 
 to introduce a standard quantity of air into a tube over mercury, and mark off the 
 height of the mercury on the tube, at the normal temperature and pressure ; then, at 
 any other temperature or pressure, by raising or lowering the tube in the mercury- 
 trough, so as exactly to bring the mercury again to the same mark, the elasticity of 
 the air is maintained constant. The gas in the eudiometer is always read off at this 
 constant degree of expansion, and this is done merely by raising or lowering it in the 
 trough, until the column of mercury within the eudiometer is of exactly the same 
 height as that in the tube containing the standard amount of air. Fig. 58 represents 
 
 Fig. 58. 
 
 the apparatus used in this method. A B is the tube containing the standard amount 
 of air, and is termed the "pressure-tube:" the upper part of it is six or seven 
 inches long, and of about the diameter of an ordinary Bunsen's eudiometer ; the lower 
 part B is of about the same length, but only f inch internal diameter. Into this pres- 
 sure-tube is introduced such a quantity of mercury that, when it is inverted in the 
 trough, the mercury stands at a convenient height in the narow tube ; at this point, the 
 mark is made which indicates the height of mercury needed at any temperature or pres- 
 
ANALYSIS (VOLUMETRIC) OF GASES. 
 
 275 
 
 Fig. 59. 
 
 sure, to reduce the enclosed air to its original volume. The mercury-trough c D differs 
 from the ordinary form in being provided with a well E, at one end, in which the 
 eudiometer is to be raised or lowered so as to bring the gas it contains to the same 
 pressure as the air in the pressure-tube. Both the eudiometer and the pressure-tube 
 are held in a perpendicular position by means of clamps F and G, which slide on up- 
 right rods. Each clamp is provided with a simple kind of slow movement, by which 
 the tube can be raised or lowered by the operator, whilst he is looking through a 
 telescope at a suitable distance. 
 
 Fig. 59 is an enlarged view of one of the clamps, which shows more distinctly how 
 the slow movement is produced. A is the part which slides up and down the vertical 
 rod ; it is furnished on the inside 
 with a small steel peg, which moves 
 in a groove, thus causing the arm 
 always to remain in the same plane, 
 c D is a tube through which the rod 
 F, carrying the clamp, passes. E is a 
 screw which retains the rod F in its 
 place, and by means of which the 
 friction on the rod passing through 
 the tube can be increased at pleasure. 
 G is a small cylinder fixed to c D ; 
 on turning this round to the right or 
 to the left, the string above or below 
 is wound on to it, and consequently 
 the rod F raised or lowered. In order 
 that the heat from the body may not 
 affect the volume of the gases in the 
 tubes, thin iron rods, some six feet in 
 length, are screwed into these cylin- 
 ders, and rest on the arm carrying 
 the telescope, as shown in fig. 58. H 
 is merely an arrangement for tighten- 
 ing the string. K. is a peg so placed 
 with regard to the stop L, that when, 
 by turning the clamp round, it is 
 pressed against the stop, the tube is 
 then in the right position for applying 
 the final adjustment and reading off. In operating with this apparatus, the pressure- 
 tube is placed immediately in front of the eudiometer, and the clamp moved up or 
 down the vertical rod till the top of the mercury inside about coincides with the mark 
 on the stem of the tube ; in the same way, the eudiometer is so adjusted that the 
 internal column of mercury is of about the same height as that in the pressure-tube. 
 The iron rods are then screwed on, and the whole allowed to cool. 
 
 The method adopted in reading off the amount of gas is, while looking through the 
 telescope, first to turn the rod connected with the pressure-tube so as to bring the 
 mercury exactly up to the mark on the stem, then raise or lower the eudiometer so 
 that the meniscus of the mercury inside it may coincide precisely with the meniscus in 
 the pressure-tube. This is easily done, as the diameter of the pressure-tube is con- 
 siderably smaller than that of the eudiometer, and the meniscus in the latter can be 
 clearly seen on both sides of the meniscus of the pressure-tube. It is convenient also 
 to have a second pressure-tube, the stem of which should be about three times as long 
 as that of the one already described. By this means, when only a small amount of 
 gas has to be measured, it can be read off at a greatly reduced pressure, and conse- 
 quently with greater absolute accuracy. In order to render the reading made with 
 one pressure-tube comparable with those made with the second, it is only necessary to 
 measure the same amount of gas at each of these degrees of expansion, this at once 
 establishes the proportion in which any amount of gas read off, at the greater degree 
 of expansion, for instance, will have to be diminished in order to render it com- 
 parable with gas read off at the lower degree of expansion. This method yields very 
 accurate results, and they are obtained with less trouble than by Bunsen's method, 
 and without any tedious calculations. 
 
 The method and apparatus next to be described is that proposed by MM. Kegn an It 
 and Keiset (Ann. Cliim. Phys. [3] xxvi. 333). Its peculiar advantage is, that 
 analyses may be made by it with very mucli greater rapidity than is possible by 
 oither of the methods previously described, and also that it does not require a room to 
 be set apart for gas analysis. 
 
 T 2 
 
276 
 
 ANALYSIS (VOLUMETRIC) OF GASES. 
 
 The economy of time is effected in two ways : first, by surrounding the gas-tubes 
 with water, which almost immediately causes their contents to assume the same 
 temperature as that of the external medium; secondly, by the use of liquid reagents 
 instead of solid, which are necessarily used in Bunsen's method. 
 
 The form and principle of M. Kegnault's apparatus will be easily understood from 
 Jigs. 60 and 61. It consists essentially of two parts, which can be easily joined and 
 
 Fig. 60 
 
 In the one part, the gas is subjected to the action of the liquid reagents, and 
 this is termed the laboratory or absorption-tube; in the other, the gas is mea- 
 sured, and it is termed the measuring-tube ; these are represented in the figures by / g, 
 and a b. The measuring tube a b, is from 15 to 20 mm. internal diameter. It is divided 
 into millimetres, and terminates above in a fine capillary tube a r, while the lower 
 end is luted into a cast iron piece NN, having two tubulations, b and <?, and a stopcock 
 .ff. To the second tubulation c t is luted a straight tube c d, open at both ends, of the 
 
 Figs. 62, 63, 64. 
 c 
 
 same diameter as the tube a b, and divided also into millimetres. The stopcock E is 
 bored through in two directions at right angles to one another, as shown in 
 figs. 62, 63, and 64, go that by turning the key in different positions, communi- 
 cation can be established between the two tubes a b and c d, or the mercury can be 
 
ANALYSIS (VOLUMETRIC) OF GASES. 
 
 277 
 
 allowed to flow from either. These tubes are surrounded by a glass cylinder filled 
 with w;tter, in which the thermometer T is immersed. During the analysis, the 
 thermometer must of course indicate a constant temperature ; should any alteration 
 havs taken place, the original temperature must be restored by the addition of hot or 
 coJd water. 
 
 The whole apparatus is fixed on a cast-iron stand z z, furnished with levelling- 
 S'^rews. The absorption tube g f, is open at the bottom and terminated above by a 
 curved capillary tube / e r. This tube dips into a small mercury 
 trough V, of cast iron, or what is still better, gutta-percha, Fig. 65. 
 
 Figs. 65 and 66 represent more clearly the form of this trough. 
 When in its place, it rests on a small iron bracket, which by means 
 of the rack i i, and the pinion o, to which the handle B is at- 
 tached, is easily moved up and down. It is retained in any 
 position by the rachet q, to which, in order to facilitate its 
 working, a weight is fixed, and as this is turned from one side 
 to the other, the rachet is thrown in or out of gear with the 
 pinion. To the ends of the capillary tubes, which terminate the Fig. 66. 
 
 absorption- and measuring- tube, are carefully luted two small 
 steel stopcocks, r r\ the ends of which exactly fit each other, 
 and have the shape represented in fig. 67, in section. In order 
 to render the joining of the two as air-tight as possible, a little 
 melted caoutchouc is applied to the faces a b and a b\ which 
 are then pressed together as tight as possible by means of a screw 
 clamp, represented in fig. 68. The laboratory-tube is held in a 
 vertical position by the clamp u, which is lined with cork, and 
 can be adjusted to the required distance from z z, by means of 
 the screw s. The measuring-tube a b is provided with two 
 platinum wires, as in the ordinary eudiometer. The following 
 account given by Regnault (Cours de Chimie, iv. 77) of an 
 analysis of a mixture of air and carbonic acid will perhaps best 
 explain how the apparatus is used. 
 
 The first operation is to fill the measuring-tube : this is done 
 by pouring mercury into the tube c d, xmtil it begins to escape 
 through the stopcock r, which is then closed. The laboratory- 
 tube is next filled by plunging it into the mercury-trough V, the 
 stopcock r being open. To fill the capillary-tube / e r, the best 
 method is simply to apply the mouth to the open end of it and 
 suck the mercury up, then close the stopcock. The tube being 
 now perfectly full of mercury, it is fixed in its place and the Fig. 68. 
 
 clamp screwed on to the stopcocks. 
 
 The gas to be analysed is now introduced into the laboratory- 
 tube, the trough V having been lowered to such a position that 
 the end of the laboratory-tube only reaches to a short distance 
 under the mercury ; the gas is then easily passed up into it. This being done, the 
 trough is again raised and the mercury allowed to flow out of the measuring-tube, by 
 which means the gas is forced over into the measuring -tube. When the mercury reaches 
 the capillary tube / e, the stopcock r is nearly closed, thus causing it to rise but slowly, 
 and when the column of mercury arrives at a certain mark a on the horizontal part of 
 the capillary tube, the stopcock r', is closed. The level of the mercury is thus 
 brought to a given division a, of the tube a 6, and the difference of height of the two 
 columns can immediately be read off on the scale of the tube c d. The water should 
 be well agitated by blowing air into it through a tube which descends to the bottom of 
 the cylinder. The height of the thermometer and barometer must also be observed. 
 
 In order that no calculation should be necessary for estimating the tension of 
 aqueous vapour, the gas is always saturated with moisture ; this is done by moistening 
 the sides of the measuring-tube a b : the mercury, in passing through, merely removes 
 the excess of water, and always leaves a small quantity adhering to the sides of the 
 tube. Let t be the temperature of the water, which, as before stated, must be station- 
 ary during the analysis, / the tension of the aqueous vapour at this temperature ; v 
 the volume of the gas ; H the height of the barometer ; and lastly, h the difference 
 of the height of the mercury in the two tubes. H + h f is then the elasti- 
 city of the gas when dry. Having thus measured the quantity of gas taken, the next 
 operation is to absorb the carbonic acid present. The trough V is again lowered and 
 by means of a bent pipette, a single drop of a strong solution of caustic potash is 
 introduced into the laboratory-tube. Mercury is then poured into the tube c <?, and 
 the stopcock R turned so as to establish communication between the tubes a b and c d. 
 On opening the stopcocks r r' t the gas is then forced back into the laboratory- tube. 
 
 T 3 
 
 Fig. 67. 
 a! 
 
278 ANALYSIS (VOLUMETRIC) OF GASES. 
 
 As the mercury in it sinks, the caustic potash moistens the sides of the tube, thus 
 exposing a very large absorbing surface. In a few minutes, the whole of r,he carbonic 
 acid is absorbed ; and the absorption may be rendered still more speedy and certain, by 
 raising the trough and opening the stopcock r, so that the gas may again be drawn into 
 the measuring tube and afterwards forced back a second time into the laboratory-tube, 
 thus bringing it in contact with a fresh surface of potash. It has been shown that after 
 this operation has been repeated twice, no appreciable amount of carbonic acid remains 
 unabsorbed. As it is essential that none of the absorbing liquid should ever pass 
 over into the measuring-tube, the error arising from an amount of gas remaining in 
 the capillary tube f e r, is best eliminated by always making this a constant quantity, 
 which is done by closing the stopcock r', when the column of liquid reagent or mercury 
 arrives at a certain mark <r. 
 
 The absorption being completed, the level of the mercury in the tube a b is again 
 brought to the mark o, and the difference of height ti of the mercury in the two tubes 
 a b and c d, is read off. H' the height of the barometer, is also noted. If the tempe- 
 rature of the water in the cylinder has changed, it must be restored to the original 
 temperature t, by the addition of hot or cold water. The elastic force then of the gas 
 deprived of carbonic acid and dry, is H' + h' f; and consequently (H -t- h /) 
 (If + h' /) H H' + h h', is the diminution of elastic force, caused by the 
 
 absorption of the carbonic acid ; and ^7 j. 7 represents the proportion of 
 
 carbonic acid in the gas when dry. The proportion of oxygen in the remaining gas 
 has now to be determined. The laboratory-tube is detached, thoroughly washed, and 
 dried, first by means of paper, and afterwards by bringing it into connection with an 
 air-pump. It is then again filled with mercury and fitted on to the measuring-tube. 
 The trough u is now raised, and the stopcock 7? opened. On now turning the cocks r r', 
 the mercury in the laboratory -tube passes into the capillary-tube a r, and is allowed to . 
 proceed as far as a given mark T ; when it reaches this mark, the stopcocks r r' are closed. 
 The mercury in the measuring-tube is then again brought to the point a, and the 
 difference of the level k" and the height of the barometer H" read off. H" + h" f 
 is therefore the elastic force of the dry gas now in the apparatus, a small quantity 
 (about 37^0) of the whole having been lost by detaching the laboratory-tube. This 
 second measurement prevents any inaccuracy thence arising. 
 
 A proper quantity of hydrogen is now introduced, and a uniform mixture of the 
 whole produced by passing the gas two or three times backwards and forwards from 
 the laboratory-tube into the measuring tube. When thoroughly mixed, the column of 
 mercury is again brought to the mark r, and the gas in the measuring tube to the 
 point a. The difference of height k'" of the two columns of mercury is read off, and 
 the height H'" of the barometer. H'" + h'" f is therefore the elastic force of the 
 mixture of hydrogen, oxygen, and nitrogen. The capillary-tube ra, is now com- 
 pletely filled with mercury, so that none of the gas shall escape combustion, and an 
 electric spark passed through the mixture. After the explosion, the stopcocks r r are 
 carefully opened and the gas subjected to a slight pressure, so that the mercury is 
 forced back along the capillary-tube till it arrives at the point r ; the stopcocks are 
 then again closed, and the gas expanded as before to the mark a. Its elasticity 
 now be represented by H"" + h"" - f. Consequently (H'" + K" - f) (H"" + 
 h"" /) = H'" H"" + h'" h"", is the elastic force of the gaseous mixture 
 which disappeared during the combustion ; (H'" H"" + h'" h"") is the elastic 
 force of the oxygen contained in the dry gas, of which the elastic force was H" + h" f; 
 
 and i jjT, -pi f i 3 ^ ne proportion of oxygen contained in the gas when 
 
 freed from carbonic acid, whence the proportion of oxygen in the original gas may be 
 easily deduced. 
 
 As the gag is made to occupy a constant volume during the whole analysis, this 
 entirely removes the necessity of calibrating any of the tubes. This apparatus may, 
 however, be used in a different way, and then the calibrating of the tube a b becomes 
 necessary. In this case, instead of always bringing the gas to a constant volume and 
 reading off the pressure it supports, the pressure is retained constant, and the difference 
 of volume read off. The calibration of the tube a b is effected by filling it completely 
 with mercury, and then allowing a small quantity to flow out througli the stopcock B, 
 collecting and weighing this, then reading off on the tube the height through which 
 the mercury has fallen. The temperature of the water in the cylinder should be kept 
 constant during the whole operation. 
 
 The apparatus of MM. Regnault and Reiset leaves but little to be desired with 
 regard to the rapidity with which analyses can be made ; but this rapidity is to a 
 certain extent obtained at a sacrifice of accuracy, considerable change in the bulk of 
 gas operated on being represented by only a small change in the amount of pressure. 
 In a comparison made by Messrs. Frankland and Ward, of the methods of Bunsen 
 
ANALYSIS (VOLUMETRIC) OF GASES. 
 
 279 
 
 Fig. 69. 
 
 and Regnault, it was shown that an error of i of a millimetre in the first obser- 
 vation would cause in Kegnault's method an error in the percentage amount, seven 
 times as great as would be the case when Bunsen's method was adopted. There n 
 also considerable practical difficulty in maintaining the water in the cylinder at precisely 
 the same temperature for any length of time together. 
 
 Messrs. Frankland and Ward have constructed (Chem. Soc. J. vol. vi. p. 197) 
 another form of apparatus for the analysis of gases, which, in mechanical construction 
 and in the method of working . 
 it, is very similar to the ap- 
 paratus of Kegnault and Rei- 
 set, but possesses at the same 
 time many important advan- 
 tages over it. The effect of at- 
 mospheric pressure on the gas 
 is entirely removed ; the prin- 
 ciple adopted in measuring the 
 amount of gas yields very ac- 
 curate results ; the gas may be 
 expanded to almost any amount, 
 rendering this apparatus one of 
 considerable importance. Fig. 
 69 is a drawing of the appara- 
 tus. "It consists of the tripod A, 
 furnished with the usual level- 
 ling screws, and carrying the 
 vertical pillar B B, to which is 
 attached on the one side the 
 movable mercury-trough c, of 
 gutta-percha, with its rack and 
 pinion a a, and on the other 
 the glass cylinder D D, with its 
 contents. The cylinder is 36 
 inches long, and 4 inches in- 
 ternal diameter; its lower ex- 
 tremity is firmly cemented into 
 an iron collar c, the under 
 surface of which can be screwed 
 perfectly water-tight upon the 
 bracket-plate d, by the inter- 
 position of a vulcanised caout- 
 chouc ring. The circular iron 
 plate d is perforated with three 
 apertures, into which the caps 
 e e e are screwed, and which 
 communicate below the plate 
 with the x-piece E E. This 
 latter is furnished with a double-waycock /, and a single-waycock 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 and H are three glass tubes which 
 are firmly cemented into the caps e e e. F and H are each 15 to 20mm. internal 
 diameter, and to avoid any difference in the capillary action, are selected of as nearly 
 the same bore as possible. The tube G is somewhat wider, and may be continued to 
 any convenient height above the cylinder. H is accurately graduated into milli- 
 metres, and is furnished at the top with a small funnel i, into the neck of which a 
 glass stopper, about 2 mm. in diameter, is carefully ground. The tube F terminates 
 at its upper extremity in the capillary-tube k, which is carefully cemented into the 
 small steel stopcock /. F has also fused into it at m two platinum wires, for the passage 
 of the electric spark. After this tube has been firmly cemented into the cap e, its in- 
 ternal volume is accurately divided into ten equal parts. This is done first by filling 
 it with mercury from the supply tube G, up to its junction with the capillary tube Jc, and 
 then allowing the mercury to run off through the nozzle h, until the highest point of the 
 meniscus stands at the division 10 previously made, so as exactly to coincide with the 
 zero of the millimetre scale on H. The weight of the mercury thus ' run off is care- 
 fully determined, and the tube is again filled as before, and divided into ten equal 
 parts, by allowing the mercury to run off in successive tenths of the entire weight., and 
 marking the height of the top of the meniscus after each abstraction of the metal, 
 
 T 4 
 
 Jill!' 
 
280 ANALYSIS (VOLUMETRIC) OF GASES. 
 
 by screwing a small copper ring on to the tube at that point. By using proper pre- 
 cautions with regard to temperature, &c., an exceedingly accurate calibration can be 
 made in this way. In practice, however, it is found much easier to make the calibra- 
 tion in the following manner. The ten copper rings are screwed on to the tube first, 
 at about equal distances apart, but without any relation to the capacity of the tube, 
 which is afterwards ascertained by expanding the same volume of gas down to each 
 of the ten divisions, and reading off the height of the column of mercury in the tube 
 H in each instance. The way in which the laboratory tube j is joined to the rest of 
 the apparatus is precisely similar to that adopted by. MM. Eegnault and Eeiset, and 
 already described. 
 
 When the instrument is thus far completed, it is requisite to ascertain the height 
 of each of the nine upper divisions on the tube above the lowest or tenth division ; 
 this is very accurately effected in a few minutes by carefully levelling the instrument, 
 filling the tube G with mercury, opening the cock I, and the stoppered funnel i, and 
 placing the cock / in such a position as to cause the tubes F H to communicate with 
 the supply-tube G. On now slightly turning the cock g, the mercury will slowly rise 
 in each of the tubes F and H ; when its convex surface exactly coincides with the 
 ninth division on F, the influx of metal is stopped, and its height in H accurately 
 observed ; as the tenth division on F corresponds with the zero of the scale upon H, 
 it is obvious that the number thus read off is the height of the ninth division above 
 the 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 
 inside of the tubes F and H are once for all moistened with distilled water, by the 
 introduction of a few drops into each, as in Kegnault's apparatus. 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 /, that cock is also closed. The tubes F and H are now apparently 
 filled with mercury, but a minute and imperceptible film of air still exists between 
 the metal and the glass : this is effectually got rid of by connecting F and H with 
 the exit-tube h, and allowing the mercury to flow out until a vacuum of several inches 
 in length has been produced in both tubes. By allowing the instrument to remain thus 
 for an hour, the whole of the film of air above mentioned will diffuse itself into the 
 vacuum, and will become visible as *a minute bubble in each tube, on allowing the 
 vacuum to be filled up from the supply-tube G. By opening for a moment the stopper i 
 and the cock /, whilst G is full of mercury, these bubbles are expelled. The absorption 
 or laboratory-tube i being then filled with quicksilver, and attached to I by the screw 
 clamp, the instrument is ready for use. 
 
 The method of introducing the gas, applying the absorbents, and passing the gas 
 from one tube to the other, is in this apparatus so precisely similar to that adopted in 
 using Regnault's apparatus, and before described, that it need not be further dwelt 
 upon. The method of reading off the amount of gas is, however, different, and 
 requires a few words of explanation. When the gas has been passed over into 
 the tube F, mercury is allowed to flow out of the stopcock /, until a vacuum of two 
 or three inches in length is formed in H, and the metal in F is just below one of 
 the divisions ; the cock / is then reversed, and the mercury very gradually admitted 
 from G until the highest point in F exactly corresponds with one of the divisions on 
 that tube ; that this is really the case, must afterwards be ascertained by viewing it 
 through a telescope. The height of the mercury in the tube H is then read off. If 
 the division on the tube F, to which the gas has been expanded is, for instance, the 
 fourth, then, from the number read off on the tube H must be deducted the height of 
 this fourth division above the zero point of the tube. The remainder will express the 
 volume of the gas ; but in order to compare this with subsequent readings made at 
 other divisions upon F, the number thus obtained, which represents the pressure of the 
 gas, is reduced to what it would have been had the gas been expanded to the tenth 
 division of F. This is very simply done, by merely multiplying the number repre- 
 senting the pressure of the gas by a fraction whose denominator is 10, and numerator 
 the number of the division to which the gas has been expanded ; thus, in the case above 
 cited, the multiplier would be 0'4. 
 
 The following are the results of an analysis of air made by Messrs. Frankland and 
 Ward. 
 
 Volume of air used. (Determined at fifth division on F.) 
 
 Observed height of mercury in H .... 673 '0 mm. 
 
 Height*of fifth division above zero .... 383*0 
 
 Corrected pressure of gas 290-0 
 
 -5 
 
 Connected pressure of gas at tenth division . . . 145'0 
 
ANALYSIS (VOLUMETRIC) OF GASES. 281 
 
 Volume after the admission of hydrogen. (Determined at sixth division.) 
 
 Observed height of mercury in H .... 772*3 mm. 
 
 Height of sixth division above zero .... 304*0 
 
 Corrected pressure of gas 468*3 
 
 -6 
 
 Corrected pressure of gas at tenth division . . . 280*98 
 
 Volume after explosion. (Determined at fifth division.) 
 
 Observed height of mercury in H .... 763*3 
 
 Height of fifth division above zero .... 383*0 
 
 Correct pressure of gas 380*3 
 
 5 
 
 Corrected pressure of gas at tenth division . . . 190*15 
 
 Results. 
 
 Volume of air used % . 145'00 
 
 Volume of oxygen 30*276 
 
 Hence : 
 
 Nitrogen 79*120 
 
 Oxygen 20*880 
 
 100*000 
 
 Greatly superior as this form of apparatus is to that of Eegnault, and capable as 
 it is of yielding accurate and rapid results, still there are defects in it which detract 
 somewhat from its practical value. The principal of these is the great difficulty there 
 exists in always maintaining the apparatus in a perfectly air-tight condition, especially 
 as the stopcocks I' and I have to be joined and separated once or twice during an analysis. 
 Considerable inconvenience has also been found to arise from the very fragile nature 
 of the laboratory- tube ; this, even when full of mercury, is only supported by the 
 capillary tube, to which it is fused, and consequently the slightest blow or pressure 
 upon it is apt to cause it to separate at this point of junction. Some difficulty is also 
 experienced in keeping the water in the cylinder at exactly the same temperature 
 during the whole course of the analysis. Regnault, as before stated, suggests adding 
 hot or cold water till the required temperature is obtained ; this is an operation 
 which takes considerable time, and without much care is likely to lead to fallacious 
 results. Dr. Frankland has proposed using a stream of water direct from the street 
 main, which enters the cylinder at the bottom, and is allowed to flow off by an exit- 
 tube near the top. This is a great improvement upon Regnault's method, but even 
 with this arrangement, slight variations occasionally occur. 
 
 Having now described the principal forms of apparatus used in the analysis of gases, 
 we shall proceed to state the methods to be adopted for the separation and quantita- 
 tive estimation of the different contituents which may occur in a gaseous mixture. 
 Gases which have a strong affinity for any particular reagent, are estimated directly by 
 introducing the reagent into the absorption-tube ; but since many gases are not absorb- 
 able in this manner, another and indirect method has to be adopted, as for instance, 
 in the case of hydrogen, which is estimated by exploding it with oxygen and observing 
 the diminution of volume thence ensuing. 
 
 The following list will show which gases are estimated directly and which indirectly. 
 Two of the number, namely oxygen and carbonic oxide, will be found in both lists, as 
 they can be estimated by either method. 
 
 Gases estimated by the direct method. 
 
 Hydrochloric acid (anhydrous). 
 Hydrobromic acid. 
 Hydriodic acid. 
 Hydrofluoric acid. 
 Hydrosulphuric acid. 
 
 Carbonic acid (anhydrous). 
 Oxygen. 
 Carbonic oxide. 
 Olefiant gas. 
 Nitric oxide. 
 
 Sulphurous acid (anhydrous). 
 
 Gases estimated indirectly. 
 
 Nitrogen. 
 Oxygen. 
 Hydrogen. 
 Carbonic oxide. 
 
 Light carburetted hydrogen. 
 
 Ethyl. 
 
 Methyl. 
 
282 ANALYSIS (VOLUMETRIC) OF GASES. 
 
 The gases estimated by absorption may, for analytical purposes, be conveniently 
 divided into three groups. 
 
 1st Group: Hydrochloric acid; Hydrobromic acid; Hydriodic acid. These are 
 absorbable by means of sulphate of sodium. 
 
 2nd Group : Hydrosulphuric acid ; Sulphurous acid ; Carbonic acid. These are 
 absorbed by caustic potash, but not by sulphate of sodium. 
 
 3rd Group: Oxygen; Nitric oxide; Carbonic oxide; Olcfiant gas. These are 
 neither absorbed by sulphate of sodium nor by caustic potash. With regard to the 
 manner of applying the reagent, if the apparatus of Eegnault or Frankland be used 
 a few drops of a very strong solution of the reagent are introduced into the laboratory- 
 tube, by means of a bent pipette, as little of the liquid being used as possible, to pre- 
 vent any appreciable loss arising from its absorbing power. But in using Bunsen's 
 method, or that proposed by Williamson and Russell, the reagent must be introduced 
 in a solid form if possible, or if necessarily a liquid, some porous substance must bo 
 saturated with it. 
 
 Estimation of the Gases of the 1st Group. The sulphate of sodium is intro- 
 duced into the gas by^st melting it in its water of crystallisation, and then dipping 
 into it the end of a platinum wire which has been bent into a short coil ; this is repeated 
 several times until a ball of the sulphate of sufficient size is obtained. If much of 
 these acids is believed to be present, the ball should be of a large size, or else the 
 sulphate of sodium is apt to become deliquescent, and run down the sides of the tube. 
 All aqueous vapour must also be carefully removed from the gas before introducing the 
 sulphate of sodium. This is best accomplished by means of a ball of phosphoric acid, 
 which may easily be made by dipping the coiled end of a platinum wire into hot liquid 
 phosphoric acid ; a drop adheres to the wire, and then as the acid cools the size of the 
 ball is increased to about that of a large pea, by turning it round in the viscous melted 
 mass. The thickness of the platinum wires used in these experiments should be such 
 that the balls of reagent may be easily pushed into the eudiometer without the wire 
 bending. Great care must also be taken that the surface of the ball is as smooth as 
 possible, or adhering air will be introduced into the gas, and some of the gas removed 
 on withdrawing the ball. Oxide of bismuth or zinc may also be used for absorbing 
 the members of this group. A ball of these substances is best made by applying the 
 moist oxide to the end of the platinum wire, and then igniting it in the flame of a 
 spirit-lamp. The results obtained with these absorbents are, however, generally not 
 quite so accurate as those obtained with the sulphate of sodium. Thediiferent members 
 of this group cannot be separated by any eudiometrical process. If several of them 
 occur together, the ball of sulphate of sodium used for their absorption must after- 
 wards be dissolved in water, and the solution analysed in the ordinary way. 
 
 Estimation of the Gases of the 2nd Group. As stated above, the members of 
 this group are all absorbed by caustic potash. A ball of this substance is made by 
 fusing caustic potash and adding sufficient water to render it, when cold, soft enough to 
 receive an impression from the nail ; the end of the platinum wire bent into a coil is 
 then placed in a bullet-mould of convenient size, and the fused potash poured in. If 
 the ball should adhere firmly to the mould when cold, as is sometimes the case, heat 
 must be applied ; it will then easily be removed. On xising a potash-ball for absorbing 
 gases, it must always be moistened with water before introducing it into the gas. 
 When much gas has to be absorbed by this means, the potash-ball should, after some 
 hours, be removed from the eudiometer, washed, and then again introduced. It should 
 be allowed to remain some four to six hours in contact with the gas, in order to ensure 
 complete absorption. 
 
 Hydrosulphuric acid. This gas is best absorbed by means of a ball of peroxide of 
 manganese. The manganese is very finely powdered and made into a thin paste, with 
 water ; this is introduced into a bullet-mould with the platinum wire in it, and then 
 dried on a hot sand-bath. If, however, this ball were at once introduced into a 
 gaseous mixture, it would, from its porous nature, absorb an appreciable amount of 
 other gases besides hydrosulphuric acid. To obviate this, the ball before being used 
 should be thoroughly moistened with a syrupy solution of phosphoric acid ; care must 
 however be taken that this does not soften the ball, or it may fall to pieces on attempt- 
 ing to introduce it into the eudiometer. There is also another method of estimating 
 this gas, but it is applicable only when sulphurous acid is not present. A potash-bull 
 containing a large quantity of water, but not moistened externally, so that, on with- 
 drawing it, none of the potash remains in contact with the mercury, is introduced into 
 the eudiometer : this absorbs the hydrosulphuric and carbonic acid, if any is present. 
 " Distilled water acidulated with acetic acid, is then boiled in two flasks until all the 
 dissolved air has been removed ; the contents of one flask is then poured, whilst boiling, 
 into the other, filling it up to the top of the neck. The flask is then well closed with 
 
ANALYSIS (VOLUMETRIC) OF GASES. 283 
 
 a cork covered with a plate of caoutchouc, so that no bubble of air is left between the 
 liquid and the caoutchouc plate. As the liquid cools, the cork is pushed further into 
 the neck, in order to prevent the formation of a vacuous space and the possible en- 
 trance, of air. The ball of potash, cut off from its platinum wire immediately on with- 
 drawal from the gas, is allowed to dissolve in this liquid when cool, and a few drops 
 of a clear solution of starch are added." * The amount of hydrosulphuric acid present 
 is then determined by means of a standard solution of iodine. In order to free the 
 determination from any error which might arise from impurities in the potash, the 
 experiment is repeated exactly in the same way with a ball of the same potash, but 
 containing no sulphide of potassium The amount of iodine used in this case is then 
 subtracted from the amount used in the former experiment. 
 
 Sulphurous acid. This gas is estimated by exactly the same methods as those 
 adopted for hydrosulphuric acid. 
 
 Carbonic acid. Caustic potash is the reagent always used in determining the 
 amount of this gas in any mixture. The method of preparing the ball, and the neces- 
 sary precautions in using it, were described when speaking of potash as the general 
 absorbent of this group. 
 
 Estimation of the Gases of the 3rd Group. This group consists of four gases 
 not absorbable either by sulphate of sodium or by caustic potash. They will be treated 
 in the order in which they would have to be separated from a gaseous mixture. 
 
 Oxygen. This gas may be estimated either directly or indirectly, the method to 
 be adopted in any particular case depending on the quantity present, and the nature 
 of the gases with which it is mixed. If other combustible gases are present, or if there 
 is only a small amount of oxygen in the mixture, it is always better to estimate 
 it directly. The method to be adopted in determining it indirectly will be described 
 further on. Phosphorus was formerly the substance generally used to free a gaseous 
 mixture from oxygen ; but owing to the tension of the vapour of the phosphorus acid 
 formed, the difficulty of removing it, and the action which many gases have in pre- 
 venting the union of phosphorus and oxygen at ordinary temperatures, the use of 
 this reagent is apt to lead to incorrect results. A much better method of absorbing 
 oxygen is to use pyrogallate of potassium. It may be introduced into the ab- 
 sorption-tube either by means of a papier-mache ball, or if liquid reagents are used, a 
 few drops of a strong solution of the acid are first introduced and some caustic potash 
 added to it. 
 
 The papier-mache ball is made by thoroughly macerating some bibulous paper in 
 water, then, having introduced the platinum wire into a bullet mould, and tied the 
 two handles together so that it cannot open, as much of the pulp is forced in round the 
 platinum wire as possible. After being dried on a sand-bath, a hard compact ball is 
 thus formed ; this is thoroughly saturated with the pyrogallate of potassium, and then 
 immediately introduced into the gas. The absorption of oxygen by this means is not 
 always very rapid, and it is often necessary to withdraw the ball from the eudio- 
 meter, again saturate it with the pyrogallate solution, and introduce it a second time 
 into the eudiometer. 
 
 Nitric oxide. This gas and oxygen can, of course, never occur together. The best 
 method of estimating it, is first to convert it into nitrous acid and then absorb the acid 
 thus formed, by potash. For this purpose, afew bubbles of oxygen are introduced into 
 the gas in the absorption-tube, and afterwards potash, either in the solid or liquid 
 form. When the absorption is complete, a further quantity of oxygen is added ; if 
 after this addition, no absorption is caused by the potash, then an excess of oxygen is 
 present, but if absorption again takes place, more oxygen must be added. Having in 
 this manner ascertained that the whole of the nitric oxide is removed, it then only 
 remains to absorb the excess of oxygen present, by means of pyrogallate of potassium, 
 as before described. When this gas is mixed with nitrous oxide, olefiant gas, or hy- 
 dride of ethyl, this method, according to Dr. Frankland, gives good results ; but in the 
 presence of other hydrocarbons, it is possible that the nitrous acid and peroxide of 
 nitrogen might exercise an oxidising action on them, and thus vitiate the results. 
 Protosulphate of iron was also formerly used as an absorbent for nitric oxide ; but it 
 does not yield very satisfactory results. 
 
 Carbonic oxide. Like oxygen, this gas is also estimated sometimes directly, some- 
 times indirectly. At present, its direct estimation only will be treated of. This is best 
 effected by means of a concentrated solution of subchloride of copper. A papier- 
 mache ball, similar to the one used for the pyrogallate of potassium, is the best means 
 of introducing the solution into the absorption-tube, when the liquid alone cannot be 
 used. This gas is, however, generally estimated by the indirect method, which yields 
 extremely accurate results. 
 
 * Bunsen's Gasometry, p. 86. 
 
284 ANALYSIS (VOLUMETRIC) OF GASES. 
 
 Olefiant gas. This gas, together with all others of the formula OH 2n , is easily 
 and rapidly absorbed by means of anhydrous sulphuric acid, dissolved in about an 
 equal weight of the monohydrated acid. This mixture is best introduced into the gas 
 by saturating a coke bullet with it. The bullet is made by taking a finely powdered 
 mixture of equal parts of cannel coal and coke, or anthracite coal, and after intro- 
 ducing the platinum wire, compressing as much as possible of the mixture into the 
 bullet-mould, which is then carefully and slowly heated to redness. By this means a 
 hard and compact ball is easily formed. Before introducing it into the acid mixture, 
 it should always be warmed to expel any moisture present, and after being saturated 
 with acid, must be introduced into the gas as quickly as possible. The ball, when with- 
 drawn after some hours from the eudiometer, should still give off dense white fumes, 
 on coming in contact with air, thus showing that an excess of acid was present. 
 Owing to the tension of the sulphuric acid introduced, and the sulphurous acid which 
 is formed, the bulk of gas in the absorption-tube generally increases instead of dimi- 
 nishes, on first introducing the coke bullet. To remove the acid vapours thus formed, 
 after withdrawing the coke bullet, a potash-ball must be introduced. 
 
 After the coke bullet has been withdrawn, although at present there is no direct 
 method known for separating and estimating singly the different hydrocarbons having 
 the general formula C 2 H 2n , still, if two of them occur together, the amount of each can 
 be easily determined by an indirect method to be described further on. 
 
 GASES ESTIMATED INDIRECTLY. In estimating the gases belonging to this class by 
 Buusen's method, the long eudiometer is always used. After having completed the ab- 
 sorptions in the short tube, a portion only of the gas is introduced into the eudiometer, 
 the amount depending on the nature of the gases operated on. In most cases, a 
 volume occupying about 120 mm. on the scale, will be found convenient. Certain 
 precautions are, however, necessary in using the tube for exploding gases. In order 
 to close securely the open end of the eudiometer, so that no gas may be forced out 
 at the moment of explosion, a small round piece of cork or wood, of rather greater dia- 
 meter than the eudiometer, is covered on one side with a thick piece of caoutchouc, 
 and the other is so shaped that it rests firmly on the bottom of the mercury-trough. 
 Before exploding the gas, the eudiometer is tightly pressed down on to the caoutchouc, 
 and held firmly in this position by a wooden arm pressing on the top of it. In order 
 to prevent any air adhering to the surface of the caoutchouc, which, after the ex- 
 plosion, owing to the diminution of pressure, might be sucked up into the eudiometer, 
 the caoutchouc, before introducing it under the mercury, should always be moistened 
 with a solution of corrosive sublimate, which causes the mercury to adhere closely 
 to it, and entirely removes the possibility of any air being introduced into the eudio- 
 meter. 
 
 It will be found convenient, as it saves much time and calculation, to form for the 
 eudiometer a table of volumes. This is done by introducing a small tube full of air, 
 and then reading off the height at which the mercury stands ; a second tube full is then 
 introduced, and the height of the mercury again read off, and so on till the eudiometer 
 is filled with air. By noting down the level of the mercury in the tube after each 
 addition of air, the successive differences of these numbers express the bulk of the 
 same amount of gas under different pressures, these pressures depending on the height 
 of mercury in the eudiometer. 
 
 The following is part of a table formed in this way : 
 
 Vol.. Height of D . fference8 . 
 
 1 . . . . 53 . . . .2 
 
 2 . . . 96 . . . .43 
 
 3 . . . . 131 . . . .35 
 
 4 . . . . 161 . . . .30 
 
 5 . . . . 187 . . . .26 
 
 The use of this table is to enable the operator to see at a glance the amount of gas 
 to be added when the mixture is to be exploded ; for instance, suppose the height of 
 the mercury in the eudiometer was 131, and the nature of the gas such that about 
 2 vols. of oxygen had to be added, in order that an explosion of the proper degree of 
 intensity should take place ; by referring to this table the operator would see at once 
 that oxygen must be added till the mercury falls to 187. As the object of the table 
 is only to show about how much gas has to be added under different circumstances, 
 any great degree of accuracy in forming it is not necessary. The readings-off of the 
 heights of the mercury, after each addition of air, may be made without the telescope, 
 and any alteration in the heights of the thermometer and barometer during the opera- 
 tion need not be taken into account. 
 
 The explosion of the gaseous mixture is best effected by means of an electric spark, 
 
ANALYSIS (VOLUMETRIC) OF GASES. 
 
 285 
 
 for obtaining which, a small Leyden jar is charged from an electrophorus or an 
 electrical machine, or else by the still simpler method adopted by Bunsen, which con- 
 sists merely in rubbing a large porcelain tube with a piece of silk on which some 
 amalgam is spread. Kuhmkorif's coil may also be advantageously used for exploding 
 gases. 
 
 Before filling the eudiometer with mercury, a drop of water should always be intro- 
 duced into the top of it, so that the volume of gas may be read off saturated with 
 aqueous vapour. 
 
 Nitrogen. This gas, from its incombustible nature, can, of course, be estimated only 
 by removing all others with which it is mixed, and measuring the amount remaining ; 
 but although it cannot be made to combine with oxygen, so as to remove it entirely 
 from a mixture, still, as is well known, the oxidation of it does often take place to a 
 considerable extent, and, if not properly guarded against, is likely to lead to very 
 serious errors in the analysis of gases. In fact, the discordant and incorrect results 
 obtained by the earlier experimenters on the composition of the atmosphere, did no 
 doubt arise in great measure from this cause. It became then a point of great im- 
 portance to ascertain whether this oxidation of nitrogen always took place when mix- 
 tures containing it were exploded, and if not, what must be the relative amounts of 
 combustible and incombustible gases present, in order that no trace of any oxide of 
 nitrogen should be formed. We are indebted to Professor Bunsen for a series of ex- 
 periments on this subject, which remove all uncertainty in thp matter. By taking 
 mixtures of atmospheric air and electrolytic detonating gas in different proportions, 
 he has clearly shown that when for every 100 volumes of non -combustible gas 26 to 
 64 volumes of combustible gas are taken, no oxidation of the nitrogen takes place. 
 
 To determine the presence of nitrogen in a mixture, the following is the process to 
 be adopted : Having removed all absorbable gases and measured off a suitable 
 quantity in the eudiometer, some pure oxygen is introduced, and the volume of gas 
 again measured. An electric spark is now passed through the mixture. Even if no 
 diminution of volume should ensue, it cannot be assumed that the gas was pure 
 nitrogen, as the combustible constituents may have existed in so small a quantity that 
 the gas was not of itself explosive. In order to ascertain whether this was the case, 
 about 40 volumes of electrolytic detonating gas must be added for every 100 volumes 
 of the incombustible gas. If, after the explosion which then ensues, the volume of gas 
 still remains unaltered, only pure nitrogen could have been present in the gas examined. 
 
 The electrolytic gas above-mentioned maybe prepared by means of the apparatus repre- 
 sented in figure 70. The tube A is an ordinary test-tube of rather strong glass, filled to 
 the level s s, with distilled water freed from air by 
 boiling, and acidulated with a few drops of sulphuric 
 acid. The open end of the tube is closed with a 
 cork provided with a gas-delivery tube, and having 
 two platinum wires passing through it, to the ends 
 of which are attached platinum plates, serving as 
 electrodes. When the outer extremities of the wires 
 are connected with the poles of a voltaic battery of ,s 
 two of Bunsen's elements, and the portions of gas 
 evolved in the first quarter of an hour are allowed to 
 escape, a chemical mixture of 2 vols. hydrogen and 
 1 vol. oxygen is afterwards obtained, which disappears 
 completely on explosion, so that there is no necessity 
 to measure the amount of it mixed with any other 
 gas. Time must, however, be allowed for it to 
 diffuse itself through the mixture already in the 
 eudiometer ; for this purpose, half to three quarters of 
 an hour should be allowed to elapse, after the introduction of this gas, before the ex- 
 plosion takes place, and the eudiometer should be well agitated. 
 
 Oxygen. By exploding the mixture containing this gas with an excess of hydrogen, 
 the quantity present may be very accurately determined, care being taken that the 
 amount of explosive gas bears a proper relation to the total amount present, so that 
 the detonation is not so violent as to endanger the safety of the tube or oxidise the 
 nitrogen if present, and also not too feeble, as in that case oxygen may escape com- 
 bustion. One-third of the total amount of contraction caused by the explosion is the 
 quantity of oxygen which was present. The hydrogen used in these experiments may 
 be generated in a small flask from pure zinc and dilute sulphuric acid. To remove 
 any traces of carbonic and hydrosulphuric acids, and to prevent sulphuric acid being 
 carried over mechanically, the gas, as it is evolved, should be made to pass through a 
 tube containing caustic potash. The evolution of gas should always be allowed to 
 take place for five or ten minutes before any of it is passed up into the eudiometer. 
 
 Fig. 70. 
 
286 ANALYSIS (VOLUMETRIC) OF GASES. 
 
 For very exact experiments, the hydrogen should be obtained by another profess, 
 which yields an absolutely pure gas, namely, from the electrolytic decomposition of 
 water. For the generation of this gas, an apparatus similar in form to that used for 
 obtaining the detonating gas (fig. 70), may be used. Instead, however, of two 
 platinum plates, only one is used, and the positive pole consists of a platinum wire 
 melted into the decomposing cell at the bottom, and there brought in contact with a 
 layer of mercury amalgamated with zinc. The acid liquid is of the same degree of 
 strength as in the former apparatus. On now passing the current of a battery through 
 it in the proper direction, pure hydrogen is evolved, and is dried by passing through 
 a small vessel containing sulphuric acid, or a tube containing chloride of calcium. 
 
 Hydrogen. The method of estimating this gas is precisely the reverse of that 
 adopted for the estimation of oxygen. The amount of hydrogen present is represented 
 by | of the contraction caused by explosion. The oxygen added is best prepared from 
 powdered chlorate of potassium, contained in small retorts of about the capacity of 
 eight or ten cubic centimetres. 
 
 These little retorts are easily made by blowing a bulb at the end of a piece of glass 
 tubing, then introducing the powdered chlorate of potassium, and afterwards bending 
 the tube a little above the bulb, so as to give it the form of a retort. The open end 
 should also be bent upwards, in order that it may be introduced into the eudiometer. 
 The air is, of course, first thoroughly expelled by evolving a considerable amount of 
 gas before any is allowed to enter the eudiometer. 
 
 Carbonic Oxide. The method of estimating this gas by absorption has already been 
 explained ; it is, however, most accurately, and in most cases most easily estimated by 
 exploding it with oxygen, and then absorbing the carbonic acid formed by means of 
 potash. 
 
 Light Carburetted Hydrogen (Marsh-gas). This gas is also estimated by exploding 
 it with oxygen, and measuring the contraction which has taken place and the amount of 
 carbonic anhydride formed. This gas and all hydrocarbons containing their carbon 
 and hydrogen, as they do in a condensed form, require much greater dilution with non- 
 combustible gases, in order to modify the violence of the explosion, and prevent the 
 oxidation of any nitrogen which may be present. Pure light carburetted hydrogen 
 should be diluted with from 8 to 12 volumes of air and 2 of oxygen, in order that it 
 may be exploded so as to yield accurate results. The object of using air instead of 
 merely oxygen as the diluent is, that if the gas has afterwards be examined for 
 nitrogen, the amount of oxygen which would be present would probably be so large 
 that the eudiometer could not contain sufficient hydrogen to explode it. 
 
 Ethyl, Methyl, tyc. These hydrocarbons are easily estimated by simple combustion 
 with oxygen, and measuring the amount of carbonic acid formed, care only being 
 taken that they are sufficiently diluted with incombustible gas. To pure ethyl some 
 20 times its volume of air should be added, and 6 or 7 volumes of oxygen. Methyl, 
 on the other hand, requires only about 8 volumes of air and 2 or 3 of oxygen. In operat- 
 ing with a mixture which may contain any of these gases, and of entirely unknown 
 composition, the best method of proceeding is to add at first so much air and oxygen 
 that even if the whole of the gas were ethyl, an explosion of not undue violence would 
 take place. If the gas should not explode on passing the spark through it, then a small 
 quantity of electrolytic gas or hydrogen must be added. In this way all danger of a 
 violent explosion may be avoided. The solubility of the gases in strong alcohol may 
 sometimes be examined with advantage, in order to ascertain roughly what is the 
 composition of the gas operated on, and consequently how much diluent it is necessary 
 to add. 1 volume of alcohol will dissolve some 18 volumes of ethyl, while of methyl 
 and hydride of ethyl it dissolves only about its own volume. With regard to these 
 two gases, methyl and hydride of ethyl, since they are isomeric, and in equal volumes 
 contain the same amount of carbon and hydrogen, they cannot be distinguished by 
 any eudiometrical process. 
 
 The methods adopted for calculating the composition of the gas from the data which 
 have been thus obtained, are as follows : With the gases that are estimated directly 
 the nature of the calculation is easily understood. By taking a definite example, the 
 method used in calculating the amount of combustible gases in a mixture will be rendered 
 very obvious. Suppose then that the gas introduced into the long eudiometer contains 
 hydrogen, carbonic oxide, light carburetted hydrogen, and nitrogen. Oxygen would 
 be introduced, the mixture exploded, and the carbonic acid formed absorbed ; then to 
 determine the amount of nitrogen present, hydrogen must be added in excess, and the 
 mixture again exploded to remove the oxygen remaining. 
 
 Let a be the amount of gas in the long eudiometer, 
 
 ^ ,i , , after the addition of oxygen, 
 
 c after the explosion, 
 
ANALYSIS (VOLUMETRIC) OF GASES. 287 
 
 Let d be the amount of gas after the absorption of the carbonic acid, 
 e after the addition of hydrogen, 
 
 f after explosion. 
 
 From these observations the following data are deduced : 
 A, the volume of combustible gas. C, the volume of carbonic acid formed. 
 
 2?, oxygen consumed. D, nitrogen present. 
 
 f__i represents the amount of oxygen which remained unconsumed by the first ex- 
 
 plosion. If this quantity be deducted from d, the remainder is evidently the amount 
 of nitrogen present. 
 
 A, the volume of combustible gas which was present, is found by deducting the 
 amount of nitrogen from the original volume of the gas, thus : 
 
 By subtracting the amount of oxygen ~ consumed in the second explosion from 
 
 the amount originally added, we obtain B, the amount consumed by the combustible 
 gas, thus: 
 
 The amount of carbonic anhydride formed, is : 
 
 C = c - d. 
 
 ' The values of A, B, and C being thus known, it will be possible to calculate from 
 them that of the three unknown quantities : 
 
 a; the volume of hydrogen 
 y light carburetted hydrogen 
 
 z carbonic oxide 
 
 On undergoing combustion the hydrogen and carbonic oxide combine with half 
 their volume of oxygen, whereas the marsh-gas requires twice its volume ; and further, 
 both the carbonic oxide and marsh-gas on combustion prodxice a volume of carbonic 
 acid equal to their original volume. These data give, then, the three following equa- 
 tions : 
 
 x + y + z = A 
 
 y + z = C 
 
 and from these may be deduced the value of x, y, and s 
 
 x = A - C 
 2B -A 
 *- 3- 
 
 2B-A 
 ~~B~ 
 
 Thus is obtained the quantity of these gases present in the mixture. If another 
 combustible gas had been present, its amount might also have been determined by esti- 
 mating the water produced by the explosion as well as the carbonic acid ; or else 
 it might be determined by previously removing the carbonic oxide by subchloride of 
 copper in the manner already described. The aqueous vapour in a gas is estimated by 
 placing the eudiometer within a larger tube, and filling the space between the two 
 with steam, the heat from which, as the gas is under a diminished pressure, is quite 
 sufficient to convert the whole of the water into vapour. 
 
 If two members of the olefiant gas series OH an should occur together, the quan- 
 tity of each present may be indirectly estimated in the following way: A complete 
 analysis of the gas must be made in the ordinary manner, absorbing the olefiant gases 
 by fuming sulphuric acid, and exploding the combustible gases with oxygen. A 
 second analysis must afterwards be made ; but, instead of introducing sulphuric acid 
 to absorb the olefiant gas, oxygen is added, and the whole exploded. The difference in 
 the amount of the carbonic acid formed, and in the contraction which has taken place 
 after the explosion, is evidently duo to the olefiant gases present. 
 
288 
 
 ANALYSIS (VOLUMETRIC) OF GASES. 
 
 Let Tolume of olefiant gases = A 
 
 carbonic acid formed = 11 
 
 contraction on combustion = G 
 
 If the two gases are, for instance, believed to be ordinary olefiant gas and butylene, 
 then, since 1 volume of olefiant gas gives 2 volumes of carbonic acid, and 2 volumes 
 contraction, and 1 volume of butylene gives 4 volumes of carbonic anhydride and 
 3 volumes contraction, then, if x represent the former gas, and y the latter 
 
 x + y = A 
 
 _ B - 2A 
 
 B - 2A 
 
 * - A - -T- 
 
 The contraction C gives also a third formula : 
 
 which, combined with the first equation, gives the values of x and y to be : 
 
 y = C - 2 A 
 x = A - C + 2A 
 
 The values obtained from both these sets of equations ought to agree. 
 
 B}' means of the following table, it will be easy to ascertain what formulae have to be 
 
 adopted in calculating the amount of combustible gases present in any mixture.* 
 
 Name of Gas. 
 
 Volume 
 of Gas. 
 
 Volume of 
 Oxygen 
 consumed. 
 
 Decrease of 
 volume after 
 explosion. 
 
 Vol. of 
 carbonic 
 anhydride 
 produced. 
 
 Hydrogen 
 
 1 
 
 0-5 
 
 1-5 
 
 
 
 Carbonic oxide .... 
 
 1 
 
 0-5 
 
 0-5 
 
 1 
 
 Hydride of methyl 
 
 1 
 
 2-0 
 
 2-0 
 
 1 
 
 Olefiant gas .... 
 
 1 
 
 3-0 
 
 2-0 
 
 2 
 
 Methyl 
 
 1 
 
 3-5 
 
 2-5 
 
 2 
 
 Hydride of ethyl .... 
 
 1 
 
 3-5 
 
 2-5 
 
 2 
 
 Propylene . . . 
 
 1 
 
 4-5 
 
 2-5 
 
 3 
 
 Butylene 
 
 1 
 
 6-0 
 
 3-0 
 
 4 
 
 Ethyl 
 
 1 
 
 6-5 
 
 3-5 
 
 4 
 
 If the gaseous mixture consisted, for instance, of hydrogen, carbonic oxide, and 
 nitrogen, and if A = the volume of the gas, C the diminution after explosion, and D 
 the amount of carbonic acid produced, then taking x = hydrogen, y = carbonic acid, 
 and z = nitrogen, we have : 
 
 = A 
 
 which gives : 
 
 As another example may be taken a mixture of hydrogen, carbonic oxide, and 
 hydride of ethyl or methyl gas ; then, if x, y, and z represent the quantities of these 
 gases present : 
 
 3A + 2(7 - 4D 
 
 y = 
 
 6 
 - 2(7 
 
 D 
 
 * The Table is taken from the Handworterbuch der Cbemie. 
 
ANALYSIS, ZOOCHEMICAL ANCHOIC ACID. 289 
 
 (For further details, see Bunsen's Gasometry, translated by Roscoe, London, 1857, 
 pp. 42114 ; Regnault, " Cours elementaire de chimie, Paris, 2 me ed. iv. 73 103 ; 
 Handw. d. Chem. 2 te Aufl. i. 930978.) W. J. R. 
 
 ANALYSIS, ZOOCHEIVXXCAZ.. See ANALYSIS, ORGANIC, p. 250. 
 
 A1VTAIVEIRTIN, C 19 H 36 2 . The fatty matter extracted from grains of paradise or 
 cocculus indicus (Anamirta cocculus\ is composed of a solid glyceride, called anamirtin 
 or stcarophanin, together with a certain quantity of a free fatty acid. The seeds are 
 first freed from picrotoxine and colouring matter by digestion in ether, then exhausted 
 with hot ether, and the filtered ethereal solution is exposed to a low temperature. 
 Anamirtin then separates in arborescent crystals, which are purified by two or three 
 crystallisations from boiling absolute alcohol. It melts at 35 or 36 C., and on cooling 
 solidifies in a wrinkled mass, but does not crystallise. It is waxy and not friable. 
 (Francis, Ann. Ch. Pharm. xlii. 254.) 
 
 An amir tic acid is obtained by saponifying anamirtin with caustic potash and 
 decomposing the soap with hydrochloric acid. It then separates as a colourless oil 
 which gradually solidifies in a white crystalline mass. When dissolved in boiling 
 dilute alcohol, it crystallises on cooling in small needles, which have a nacreous lustre 
 when dry. It melts at 68 C. and solidifies on cooling in very brilliant radiating masses. 
 According to Francis (Ann. Ch. Pharm. xlii. 25 1) it contains C^H A ' 3 0\ Heintz, 
 however (Lehrb. d. Zoochemie, pp. 387, and 1671), considers it to be identical with 
 stearic acid. The sodium-salt separates from boiling absolute alcohol in elongated 
 prisms. The silver-salt is a white precipitate, soluble in ammonia, and soon blackened 
 by exposure to light. Anamirtate of ethyl is obtained by passing hydrochloric acid 
 gas for several hours into a hot alcoholic solution of anamirtic acid. It separates at 
 the surface of the liquid, in the form of a nearly colourless oil, which solidifies on cool- 
 ing. It is but slightly volatile, and is partly decomposed by distillation. It contains 
 76'4 per cent, of carbon, and 12'69 of oxygen. 
 
 AN AW AS, Dili OR ESSENCE OP. A solution of butyrate of ethyl in 8 or 10 
 times its weight of alcohol possesses the odour of the pine-apple (Ananassa sativa'), and 
 is employed in confectionery and perfumery, also to imitate the flavour of rum. The 
 butyrate of ethyl thus used must be quite free from volatile fatty acids. (Hofmann 
 Ann. Ch. Pharm. ImcTJ. 87.) 
 
 ANATASE. Octahcdrite. Titane anatase. TiO 2 . A pure or nearly pure oxide 
 of titanium crystallised in octahedrons, belonging to the quadratic or dimetric system, 
 with angles of terminal edges, = 13622 and of lateral edges 9756. The crystals 
 arc often very much elongated : hence the name, from avoir avis, erection. The mineral 
 has an adamantine lustre, exhibiting various degrees of translucency down to com- 
 plete opacity ; its colour by transmitted light is greenish-yellow ; by reflected light 
 yellow-grey, honey-yellow, hyacinth-red, clove-brown, and iron-black, more rarely 
 dark sky-blue or indigo. Cleavage distinct parallel to the octahedral faces. Specific 
 gravity 3'83 3'95, sometimes after heating, 4'11 4'16. Hardness 5*56. It is 
 brittle, with sub-conchoidal fracture, and yields a colourless powder. Streak uncoloured. 
 Infusible before the blow-pipe. Anatase is found most abundantly at Bourg d'Oisans, 
 in Dauphine, with felspar, axinite, and ilmenite. It occurs with mica slate in the 
 Orisons ; in Bavaria near Hof ; in the Fichtelgebirg, Norway ; and in the Urals ; in 
 chlorite in Devonshire ; with Brookite at Tremadoc, North Wales ; in Brazil, in 
 quartz, and in highly lustrous detached crystals. It is also said to occur in the slags 
 from the iron furnaces of Orange County, New York. (Dana ii. 122; Handw. d. 
 Chem. 2 te . Aufl. i. 990). (See BBOOKITE, KUTILE, TITANIC ACID.) 
 
 ANATTA. See ANNOTTO. 
 
 ANAUXITE. The name given by Breithaupt to a hydrated silicate of magnesium 
 and aluminium found at Bilin in Bohemia. Its composition has not yet been ascer- 
 tained with accuracy, but it contains 11 '5 per cent, water, and 557 per cent, silica. 
 It is softer than calc-spar, of a greenish-white colour, with mother-of-pearl lustre, 
 translucent at the edges. Specific gravity 2'26. Cleavage in one direction very dis- 
 tinct. A doubtful species. (Handw. d. Chem. 2 te Aufl. i. 991.) 
 
 ANCHOIC ACID. C 9 H 16 4 = C 9 H 14 2 .H 2 .0 2 . Lepargylic acid. Discovered by 
 Buck ton (Chem. Soc. Qu. J. x. 166) among the products of the oxidation of Chinese 
 wax by nitric acid; and by Wirz (Ann. Ch. Pharm. civ. 265) among the products 
 of the action of nitric acid on the solid fatty acids of cocoa-nut oil. 
 
 Preparation. 1. When Chinese wax is heated for several hours with 4 or 5 times 
 its volume of nitric acid, of specific gravity 1*39, the acid which distils over being 
 continually poured back, a greenish distillate is obtained, containing caprylic, oenan- 
 thylic, and butvric acids, and a residue consisting of anchoic acid, together with 
 
 VOL. I. U 
 
290 ANCHOIC ACID ANCHUSIN. 
 
 suberic and pimelic acids. On boiling this residue with water, evaporating the filtrate 
 to the crystallising point, pressing the crystalline crusts thus obtained, washing with 
 ether, and recrystallising from hot water, anchoic acid crystallises out pure, the other 
 acid remaining in solution. Cerotic acid also yields anchoic acid when treated with 
 nitric acid, but not so readily as Chinese wax (Buckton). 2. Several pounds of 
 the solid fatty acids of cocoa-nut oil (obtained by decomposing the soda soap with dilute 
 sulphuric acid, and distilling off the volatile acid), are digested with nitric acid for 
 several weeks till the oxidation is complete, and the mass solidifies in a white crystal- 
 line magma ; this product is dissolved in twice its volume of hot water ; and the 
 granular mixture of suberic and anchoic acids which separates is redissolved and 
 recrystallised several times, at last from weak alcohol, till the portion which first 
 crystallises out exhibits the composition of pure anchoic acid. The mother-liquor 
 separated from the crystalline magma of suberic and anchoic acids, contains several 
 other acids of the series C n H 2n - a O' (see ACIDS, p. 52) viz. pimelic, adipic, lipic, and 
 succinic acid. (Wirz.) 
 
 Properties. Anchoic acid forms snow-white aggregated nodules (Buckton); round 
 granules resembling those of suberic acid, but harder (Wirz). Melts between 114 
 and 11 6 C. (Buckton); partially at 115, completely at 124, and solidifies on cooling, 
 in a finely radiated nacreous mass (Wirz). At a stronger heat, it sublimes with 
 partial decomposition, emitting white inodorous vapours, which produce a very suffo- 
 cating effect when inhaled (Buckton): hence the name (7Xf" / , to suffocate). It 
 dissolves in 217*4 pts. of water at 18 C. and volatalises partially when the solution is 
 evaporated (Wirz). Hot water dissolves it readily, the solution becoming whiter and 
 semi-fluid on cooling (Buckton). It dissolves also in alcohol; has an acid taste and 
 reaction. 
 
 Anchoic acid is dibasic, the formula of the neutral anchoates being C 9 H M O 2 .M 2 .0 2 . 
 It also forms acid salts. Anchoate of ammonium is an amorphous mass, which dissolves 
 readily in water and alcohol, and gives off ammonia when heated. Neutral anchoate 
 of potassium forms indistinct crystalline masses, which dissolve readily in water. 
 The acids-dit, C 9 H 15 K0 4 , forms microscopic granules, which remain unaltered at 140 C. 
 It dissolves in 3 pts. of cold water, more readily in hot water ; soluble also in wood- 
 spirit (Buckton). The sodium-salt crystallises more readily than the potassium-salt, 
 Neutral anchoate of barium, C"H 14 Ba 2 4 , is obtained by neutralising the acid with 
 baryta-water, or with carbonate of barium, or by precipitating a mixture of the 
 ammonium-salt and chloride of barium with alcohol. Forms a transparent film which 
 becomes dull at 100 C. (Buckton). After drying over sulphuric acid, it forms a 
 white opaque mass, having the aspect of porcelain (Wirz). It is very soluble in 
 water, insoluble in alcohol and in ether (Buckton). It does not appear possible to 
 prepare an acid anchoate of 'oarium (Buckton). 
 
 The ammonium-salt form t a gelatinous precipitate with chloride of calcium, white 
 with acetate of lead, whitish with ferrous sulphate, light brick-red with ferric chloride, 
 and bluish-green with cupric sulphate (Wirz). It also precipitates ZTrtC-salts, mercu- 
 rous salts and mercuric salts (Buckton.) Anchoate of silver C 9 H !4 Ag 2 4 , obtained by 
 precipitation from the ammonium-salt, forms a white powder which soon decomposes 
 when moist (Wirz) : white flocks, which are permanent at 120 C., and dissolve spar- 
 ingly in water. (Buckton.) 
 
 Anchoate of Ethyl. C"H^0 8 = C 9 H'<0 4 . (C-H 5 ) 2 . Obtained by passing hydrochloric 
 acid gas into the alcoholic solution of the acid. It is a yellowish viscid oil, lighter 
 than water and having an agreeable odour. It boils at 325 C. (Buckton). Becomes 
 brown without distilling at 260 (Wirz). 
 
 or AXrCHUSXC ACZB. The colouring principle of the alkanet 
 root (Anchusa tinctoria). It is extracted by first -macerating the root in cold 
 water, to extract the matters soluble in that liquid, then drying it in a stove, and 
 exhausting with alcohol. The solution, at first red, becomes violet by boiling, then 
 of a greyish-green ; these changes of colour may, however, be prevented by adding a 
 few drops of hydrochloric acid. The extract is concentrated, and agitated with ether, 
 which then becomes charged with the colouring matter, and yields it by evaporation in 
 the form of a resinous mass. Anchusin is an amorphous substance, having a deep red 
 colour and resinous fracture : the colour is not altered by exposure to light. It softens 
 at 60 C. At a higher temperature, it gives off very pungent violet vapours, similar 
 to those of iodine ; at a very high temperature, it becomes carbonised. It is insoluble 
 in water, but dissolves in alcohol, and especially in ether ; oil of turpentine, and fixed 
 oils also dissolve it. According to Bolley and Wydler (Ann. Ch. Pharm. Hi. 14 1} 
 it contains C^H^O"; 71'33 p. c. C; 7'00 H. 
 
 Nitric acid transforms anchusin into oxalic acid and a bitter substance. Concen- 
 trated sulphuric acid dissolves it, forming a solution of a beautiful amethyst colour.' 
 
ANCHUSIN ANEMONIN. 291 
 
 The alkalis form with, anclmsin blue compounds, soluble in water, less soluble in 
 alcohol and ether. With subacetate of lead it forms a bluish-grey precipitate soluble 
 in alcohol. 
 
 The alcoholic solution of anchusin evaporated over the water-bath, leaves a blackish 
 green residue from which water extracts a brown substance. The insoluble portion well 
 washed with water and then treated with ether, yields a green extract containing, 
 according to Bolley and Wydler, C 34 H 44 8 , and formed from anchusin by fixation of 
 water, and elimination of carbonic anhydride ; 
 
 C 35 H 4o 8 + 2H 2 = C S4 H 44 8 + CO 2 . 
 
 ANDAX.USITE. Al 4 3 .Si0 8 , or 3Al 2 O 3 .2Si0 3 . A crystallised mineral, found 
 originally in the Spanish province of Andalusia, and occurring also in Scotland, Ireland 
 the Pyrenees, and other localities, in mica-slate, and others of the older rocks. It 
 forms rhombic prisms, belonging to the trimetric system, with angles of 91 35', and 
 88 27'. Specific gravity from 3'0 to 3'2. Hardness = 7'5. It is infusible before 
 the blowpipe : dissolves with difficulty in borax, forming a clear glass, and even less 
 easily in phosphorus salt. It is insoluble in acids. The alumina is generally more 
 or less replaced by the sesquioxide of iron and manganese. The minerals chiastolite 
 and cyanite have the same composition as andalusite : cyanite, however, belongs to 
 the triclinic (doubly oblique prismatic) system, and is found in the oldest plutonic 
 rocks, whereas andalusite and cyanite occur in metamorphic rocks, as in mica-slate 
 and clay-slate. Crystals are also found having the external form of andalusite, but 
 made iip of a mass of fine crystalline grains of cyanite. (Handw. d, Chem. 2 te Aufl. i. 
 991 ; Gin. iii. 412; Dana, ii. 257.) 
 
 AXXDAQUXES-WAX. (Cera de los Andaquies.) The wax of a peculiar species 
 of bee, found near the Oronoco and Amazon rivers, and used as a substitute for 
 ordinary beeswax, in the manufacture of candles, &c. According to Lewy (Ann. 
 Ch. Phys. [3] xiii. 458), it has a density of 0'917, melts at 77 C., and contains 81'6 
 per cent. C, 13-5 H, and 4*8 0. It is not, however, a definite compound, but, like 
 ordinary beeswax, is a mixture of three different fats, one of which, constituting about 
 half the entire substance, is insoluble in alcohol, melts at 72 C., and is identical with 
 palm-wax. The solution obtained by boiling the original wax with alcohol deposits 
 on cooling, a fat which melts at 82 C., and agrees in every respect with cerosin ob- 
 tained from the sugar-cane ; this substance exists in the Andaquies-wax to the amount 
 of 45 per cent. Lastly, the alcoholic mother-liquor yields by evaporation about 5 per 
 cent, of an oily fat, not yet further examined. 
 
 ACTDESXKT. A mineral resembling felspar in external appearance, but differing 
 from it essentially in composition. It may be represented by the general formula 
 
 = M 2 O.Si0 8 + Al 4 3 .3Si0 2 , or (regarding silicic acid as tribasic) = 
 
 SMO.ZSiCP + 3(APO 3 .2SiO 3 '), the symbol M denoting potassium, sodium, calcium, 
 or magnesium, which metals may replace each other in any proportions. Specific 
 gravity 2733. The mineral was originally obtained from the Andes, but has since- 
 been found in the Vosges and in other localities. (Handw. d. Chem. 2 te Aufl. i. 993.) 
 
 ANTDRBASBERGOXiXTX: and ANDREOLITE See HAHMOTOME. 
 
 ANEftXONXN. <7 30 # J2 6 (?) A crystalline body, obtained from the leaves of 
 several species of anemone, viz. Anemone pulsatilla, A. pratensis, and A. nemorosa. 
 Water distilled off these leaves deposits, after some weeks, a white inodorous substance, 
 which softens at 150 C., giving off water and acrid vapours. It is purified by 
 repeated recrystallisation from boiling alcohol. 
 
 The crystals belong to the trimetric system. In the cold, they are but sparingly 
 soluble in alcohol ; ether and water dissolve but little, even at a boiling heat ; the 
 solutions are neutral. Anemonin is a poisonous substance; applied to the skin, it 
 produces slight irritation. 
 
 By the action of alkalis, anemonin is transformed into anemonic acid. Boiled with 
 water and oxide of lead, it yields a crystalline compound, C 30 H^O u .PbO, soluble in 
 boiling water. Strong sulphuric acid blackens anemonin. Hydrochloric acid dissolves 
 it without sensible alteration. By oxidising agents, such as peroxide of manganese and 
 sulphuric acid, it is converted into formic acid. Chlorine attacks it readily when 
 heated, forming hydrochloric acid and an oily volatile body. 
 
 Anemonic Acid. This name has been applied to an acid substance produced by 
 the action of baryta- water on anemonin (Lowig and Weidmann, Pogg. Ann. xlvi. 
 45), and likewise to an amorphous substance, which is deposited together with ane- 
 monin, from distilled anemone water (Schwarz. Mag. Pharm. x. 193; xix. 168; 
 
 u 2 
 
292 ANGELIC ACID 
 
 Feliling, Ann. Ch. Pharm. xxxviii. 218). Both these substances are said to consist 
 of anemonin together with the elements of water. (G-erhardt, Traite iv. 263.) 
 
 BAXiSAM. When the root of archangel (Angelica archangelica) 
 is exhausted with strong alcohol, and the residue left after distilling off the greater 
 part of the alcohol is evaporated over the water-bath, a viscid mass is obtained, which, 
 when washed with water and digested in ether, yields a solution from which, by eva- 
 poration, a black-brown balsam is obtained, amounting to about 6 per cent, of the root. 
 This balsam is a mixed product, and on treating it with potash-ley and distilling off 
 part of the water, a small quantity of an essential oil (angelica-oil) separates ; on con- 
 tinuing to heat the mass with the alkaline liquid, a waxy body (angelica-wax), is left 
 behind: and the liquid concentrated to a certain point yields a crystalline resin, 
 angelicin. On distilling the residue with excess of sulphuric acid, butyric acid passes 
 over with the water, and afterwards angelic acid. (Buc liner, Ann. Ch. Pharm. xlii. 
 226.) 
 
 ANGELIC ACID. C 5 II 8 2 = O, [or (7 10 ZP0 3 . 7/0.] This acid exists 
 
 in the root of the archangel, Angelica archangelica (Buchner, Ann. Ch. Pharm. xlii. 
 226), and in sumbul, or moschus root, a drug imported from Asia Minor, and probably 
 also belonging to an umbelliferous plant. From archangel root it is prepared by boil- 
 ing fifty pounds of the root, cut into small pieces, with four pounds of lime and with 
 water, straining through a cloth, concentrating the liquid, and distilling it with dilute 
 sulphuric acid. A complex distillate is then obtained, which is neutralised with potash, 
 and evaporated to dryness over the water-bath. The residue, distilled with sulphuric 
 acid diluted with twice its weight of water, yields first a distillate of water, acetic acid, 
 and valerianic acid, and afterwards angelic acid, part of which crystallises in the neck 
 of the retort, while the rest passes into the receiver ; on leaving the distilled liquid in 
 a cold place for some days, the angelic acid dissolved in it crystallises out. The 
 crystals are washed with a small quantity of water, and repeatedly crystallised to free 
 them from valerianic acid (Meyer and Zenner, Ann. Ch. Pharm. Iv. 307). From 
 sumbul root the acid is obtained by exhausting the root with alcohol, evaporating the 
 filtered solution, boiling the residual balsam with strong potash-solution, filtering to 
 separate a volatile oil, mixing the brown-red alkaline filtrate with sulphuric acid, 
 which separates a dark brown oil, and distilling this oil with water, added at intervals 
 as long as the distillate continues to be mixed with drops of oil. This distillate, set 
 aside in a cold place, deposits angelic acid, which may be purified by twice saturating 
 it with carbonate of sodium, distilling with sulphuric acid, then distilling it alone, and 
 lastly, boiling it for a long time to separate sumbulamic acid. (Keins^h, Jahrb. pr. 
 Pharm. vii. 79.) 
 
 Angelic acid is also produced by heating the essential oil of chamomile (Anthemis 
 nobilis) which consists of angelic aldehyde, together with a hydrocarbon (C 5 H 8 ) 
 with hydrate of potassium : 
 
 C 5 H 8 + KHO = C 5 H 7 K0 2 + 2H 
 
 Angelic Arigelate of 
 
 aldehyde. potassium. 
 
 The oil must be gently heated with pulverised and tolerably dry potash, till the 
 temperature of the mass rises considerably, and hydrogen begins to escape. If the 
 source of heat be then removed, the action goes on by itself, the hydrocarbon vola- 
 tilises, and angelate of potassium remains mixed with the excess of hydrate. On 
 dissolving this residue in water, taking off the small remaining portion of oily hydro- 
 carbon with a pipette, and treating the solution with sulphuric acid, angelic acid rises 
 to the surface in the form of an oil, which solidifies in a crystalline mass on cooling. 
 This mode of preparation is much more productive than the preceding, provided the 
 application of heat be discontinued at the right time. If it be continued too long, with 
 the view of expelling the whole of the hydrocarbon not attacked by the potash, a con- 
 siderable portion of the angelic acid will be resolved into acetic and propionic acids : 
 
 C 5 H"0 2 + 2H 2 = C 2 H'0 2 + C 3 H 6 2 + H 2 , 
 
 the admixture of which greatly impedes the crystallisation of the angelic acid. 
 (Gerhardt, Traite ii. 449.) 
 
 Angelic acid is also produced, together with oreoselin, by treating peucedanin with 
 alcoholic potash : 
 
 C 12 H 12 S + KHO = C S H 7 K0 2 + C 7 H 8 2 
 
 Peuce- Angolate Oreoselin. 
 
 danin. of potassium. 
 
 (Wagner, J. pr. Chem. bui. 275.) 
 
 Angelic acid crystallises in large long prisms and needles, which are colourless and 
 
ANGELIC ACID ANHYDRIDES. 293 
 
 transparent. It melts at 45 C., boils at 190, and distils without decomposition. It 
 has a peculiar aromatic odour, a sour but aromatic taste, and reddens litmus. It burns 
 with a bright and rather smoky flame. It dissolves sparingly in cold, but abundantly 
 in hot water, whence it crystallises in needles on cooling. In alcohol, ether, oil of 
 turpentine, and fat oils, it dissolves with great facility. 
 
 Angelic acid is monobasic, and belongs to the series of acids whose general formula 
 
 is [ 0, the other known members of which are acrylic acid (C 3 ), pyroterebic 
 
 (O), hypogaeic (C 16 ), and oleic (C 18 ). 
 
 The "angelates of the alkali-metals are soluble in water and alcohol. The calcium- 
 salt, C 5 H 7 Ca0 2 + H 2 0, forms shining laminae, very soluble in water. The soluble 
 angelates form with lead-salts, a white precipitate, C 5 H 7 Pb0 3 , soluble in a large 
 quantity of water ; with ferric salts, a flesh-coloured insoluble precipitate ; with cupric 
 salts, a bluish-white sparingly soluble precipitate ; with mercurous nitrate, 'a white 
 precipitate, which soon turns grey and redissolves ; with mercuric chloride, no pre- 
 cipitate ; and with nitrate of silver, a white precipitate, which dissolves in a large 
 quantity of water, forming a solution which after a while deposits metallic silver. A 
 somewhat acid solution of oxide of silver in the boiling aqueous acid, yields, when 
 evaporated at the gentlest possible heat, small greyish-white crystals of the normal 
 silver-salt, C 5 H 7 Ag0 2 , sometimes also laminae of a basic salt. (Meyer and Zenner.) 
 
 Anqdate of Ethyl, Angelic Ether, is obtained by distilling angelate of sodium with 
 a mixture of 1 pt. strong sulphuric acid, and 2 pts. of 94 per cent, alcohol. It is a 
 colourless oily liquid, which smells like sour apples, has a sweetish, burning, aromatic 
 taste, and excites coughing and headache when inhaled. (Keinsch and Keeker, 
 Jahrb. pr. Pharm. xvi. 12.) 
 
 ANGELIC ANHYDRIDE, or Anhydrous Angelic Acid, C 10 H 14 3 = (C 5 H 7 0) 2 0. 
 Produced by the action of oxychloride of phosphorus on angelate of potassium : 
 
 PO.C1 = o + POTP t 3KC1 
 
 6 at. angelate Oxj'chloride 3 at. angelic 
 of potassium. of phosphorus. anhydride. 
 
 The viscid oil resulting from the action yields, when treated with carbonate of sodium 
 and then with ether, a solution which leaves the anhydride on evaporation. It is a 
 perfectly neutral, limpid oil, heavier than water, and having a peculiar odour quite 
 different from that of angelic acid. It does not crystallise, even at the temperature of 
 a mixture of ice and salt. When distilled, it begins to boil at 240 C., but the boiling- 
 point soon rises to 250, and the compound is subsequently decomposed, yielding a 
 distillate of angelic acid and a neutral oil, and leaving a carbonaceous residue. _ The 
 anhydride is but slowly rendered acid by the action of water, but dissolves readily in 
 strong alkaline liquids. Aqueous ammonia first converts it into a buttery mass, and 
 then dissolves it. In contact with aniline, it becomes strongly heated, and deposits 
 crystals of phenyl-angelamide, N.H,C 6 H 5 ,C 5 H 7 0. (Chiozza, Ann. Ch. Phys. [31 TTTJT. 
 210.) 
 
 AXrGXXiXCXN. A crystalline substance obtained, according to Buchner, by treat- 
 ing angelica-balsam with potash (p. 287). 
 
 AXTOXi ARXTE. A variety of vivianite, found at Arglac, in the department of the 
 Haute- Vienne, France. 
 
 ANGLE SITE. Native Sulphate of Lead. 
 
 An organic base, said by Brands to exist in true angustura 
 bark, Cusparia fibrifuga. Its existence is doubtful. 
 
 ANHYDRIDES. Secondary Negative Oxides, or Oxides of Acid-radicles. These 
 bodies are also often called anhydrous acids, and are sometimes even confounded with 
 acids. As regards their composition, they stand in the same relation to acids as oxide 
 of potassium, K 2 0, to potash, KHO ; or, generally, as anhydrous (secondary) oxides, 
 to hydrates (primary oxides) : that is, they represent one or more atoms'of water, 
 wH 2 6 (the substance taken as the standard of comparison for all oxides), in which 
 the whole of the hydrogen is replaced by one or more negative radicles ; while the 
 corresponding acids represent one or more atoms of water in which the same radicles 
 replace one half of the hydrogen. 
 
 For example : 
 
 Hypochlorous anhydride = C1.C1.0, hypochlorous acid = H.C1.0, 
 
 Nitric = N0 2 .N0 2 .0, nitric = H.N0 2 .0, 
 
 Acetic = C 8 H 3 O.C 2 H 3 0.0, acetic = H.C 2 H 8 O.O, 
 
 Benzoic . = C 7 H 5 O.C 7 H 5 0.0, benzoic = II,C 7 H 5 0.0,' 
 
 ul 
 
294 ANHYDRIDES. 
 
 Aceto-benzoic anhydride = C 2 H 3 O.C'H 5 0.0, 
 
 Sulphuric = SO-.O, sulphuric acid = H 2 .S0 2 .0 2 , 
 
 Succinic = C 4 H 4 2 .0, succinic = H 2 .C'H 4 2 .0 3 , 
 
 Phosphoric = PO.PO.O 3 , phosphoric = IF.PO.O 3 . 
 
 From these instances it is evident that there are three classes of anhydrides, namely. 
 (a) those which derive from 1 at. water by the replacement of II- by 2 atoms of the 
 same monatomic acid-radicle (hypochlorous, acetic, &c.), or by 2 different monatomic 
 radicles (aceto-benzoic, &c.) ; (b) those which derive from 1 at. water by the replace- 
 ment of H 2 by 1 atom of a diatomic acid-radicle (sulphuric, &c.) ; (c) those which 
 derive from 3 at. water by the replacement of H 6 by 2 atoms of a triatomic acid-radicle 
 (phosphoric). Anhydrides deriving from 2 at. water have not yet been shown to 
 exist. 
 
 All anhydrides are more or less quickly converted into acids by the action of water 
 or of hydrates ; in the dry state, or when dissolved in ether or other liquids which do 
 not. change them into acids, they are without action on litmus or other vegetable 
 colours. 
 
 Anhydrides (a) are obtained by the action of chlorides of monatomic acid-radicles on 
 monatomic acids or salts : 
 
 C1.C1 + Hg.Cl.0 = Hg.Cl + C1.CLO. 
 
 Hypochlorite Hypochlorous 
 
 of mercury. anhydride. 
 
 C 7 H 5 O.C1 + KC 2 H 3 0.0 = KC1 + C 2 H S O.C'H 5 0.0. 
 
 Chloride of Acetate of Aceto-benzoic 
 
 benzoyl. potassium. anhydride 
 
 They are liquid, or solid bodies, and those which contain only one acid-radicle, are 
 usually volatile without decomposition: those which contain two acid-radicles are 
 decomposed by heat into two anhydrides, each containing one radicle. 
 
 C 2 H 3 O.C 7 H S 0.0 + C 2 H 3 O.C 7 H S 0.0 = C 2 H 9 O.C 2 H 3 0.0 + C 7 H 5 O.C 7 H 5 0.0. 
 
 Aceto-benzoic Aceto-benzoic Acetic anhydride. Benzole anhydride. 
 
 anhydride. anhydride. 
 
 The anhydrides of this class, which correspond to organic acids, are insoluble or but 
 slightly soluble in water ; they dissolve in alcohol, but are gradually decomposed by it 
 forming salts of ethyl (compound ethers) ; in ether they dissolve without alteration. 
 Ammonia and its derivatives convert them into amides, or alkalamides. 
 
 C 7 H 5 O.C 7 H 5 0.0 + 2NH 3 = H 2 + 2(N.C 7 H 5 O.H 2 ) 
 
 Benzoic anhydride. 2 at. benzamide. 
 
 C*H 3 O.C 2 H 3 0.0 + 2N.CH 5 .H2 = IPO + 2(N.C*H 3 O.C 6 H 5 .H) 
 
 Acetic anhydride. 2 at. phenyl- 2 at. phenylacetamide. 
 
 amiue (aniline). 
 
 With perchloride of phosphorus they give chlorides of monatomic acid-radicles : with 
 sulphide of phosphorus, sulphanhydrides (secondary negative sulphides). 
 
 The anhydrides (b) correspond to dibasic or diatomic acids. They are formed by 
 the decomposition of these acids, or their salts, by heat. 
 
 H 2 .C 4 H 4 2 .0 2 H 2 + C 4 H 4 2 .0 
 
 Succinic acid. Succinic 
 
 anhydride. 
 
 Fe 4 .(S0 2 ) 3 .0 6 - Fe 4 3 + 3(S0 2 .O) 
 
 Sesquisulphate Sesqui- 3 at. sul- 
 
 ofiron. oxide of phuric an- 
 
 iron. hydride. 
 
 With ammonia, they give ammonium-salts of amic acids : 
 
 C 4 H 4 2 .0 + 2NH 3 = N.C 4 H 4 2 .H 2 NH 4 .0 
 
 Succinic Succinamate of ammo- 
 
 anhydride. uium. 
 
 and, lo some extent, also secondary amides (imides) : 
 
 C 4 H 4 2 .0 -f- NH 3 = H 2 + N.C 1 H 4 2 .H 
 
 Succinic anhy- Succinimide. 
 
 dride. 
 
 They react in a similar way with phenylamine (aniline) and some other primary deri- 
 vatives of ammonia. 
 
 Perchloride of phosphorus converts them into chlorides of diatomic acid-radicles. 
 
 In the case of sulphuric anhydride, SO 3 , or S0 2 .0, which has been much more 
 minutely studied than any other anhydride of this class, certain additional reactions 
 
ANHYDEITE ANIME. 295 
 
 have been observed. For instance, it has been found to combine with hydrochloric 
 acid, forming chlorhydro-sulphuric acid : 
 
 SO 3 + HC1 = HS0 3 C1 
 
 Chlorhydro- 
 sulphuric 
 acid. 
 
 as well as with other chlorides, inorganic and organic (chlorides of ammonium, 
 barium, ethyl, phenyl, &c.), to form compounds which represent the metallic salts and 
 ethers of this acid. It also combines with hydrocarbons, producing neutral compounds 
 of varying constitution : 
 
 2S0 3 + C 2 H 4 = C 2 H 4 S 2 8 
 
 Ethylene. Ethionic 
 
 anhydride. 
 
 SO 3 + 2C 6 H 6 = H 2 + C 12 H 10 S0 2 
 
 2 at. ben- Sulphoben- 
 
 zine. zide. 
 
 The comparison of these reactions with those produced by acids in similar circum- 
 stances (see pp. 43, 44), makes it clearly evident that anhydrides and acids are essen- 
 tially different in their chemical characters. 
 
 Very few triatomic anhydrides (c) are yet known. Phosphoric anhydride, P 2 5 , or 
 PO.PO.O 3 , is the only well known member of this class. It is obtained by the direct 
 combination of phosphorus and oxygen. Ammonia converts it into phosphamic acid : 
 
 PO.PO.O 3 + 2NH 3 = H 2 + 2(NH.PO.HO) 
 
 with perchloride of phosphorus it gives oxychloride of phosphorus (chloride of phos- 
 phoryl) ; and, like sulphuric anhydride, it combines with hydrochloric acid. Or. C. F. 
 
 ANHYDRITE. Anhydrous sulphate of calcium. There are six varieties of it : 
 1. Compact. Has various shades of white, blue, and red ; massive and kidney-shaped ; 
 dull aspect ; splintery or conchoi'dal fracture ; translucent on the edges ; is scratched 
 by fluor, but scratches calc-spar ; somewhat tough : specific gravity 2-850. It contains 
 a trace of sea-salt. It is found in the salt mines of Austria and Salzburg, and at the 
 foot of the Harz mountains ; also in the gypsum pits at Ashton-on-Trent, near Derby. 
 2. Granular. The scaly of Jameson, is found in massive concretions, of which the 
 structure is confusedly foliated. White or bluish colour, with a pearly lustre. Compo- 
 sition as above, with 1 per cent, of sea-salt. It occurs in the salt mines of Halle. 
 Specific gravity 2-957. 3. Fibrous. Massive ; glimmering, pearly lustre ; fracture in 
 delicate parallel fibres ; scarcely translucent ; easily broken. Found at Halle, Ischel, 
 and near Brunswick. 4. Radiated. Blue, sometimes spotted with red ; radiated, splen- 
 dent fracture ; partly splintery; translucent; not hard; specific gravity 2*940. 5. Sparry 
 or Cube-spar. Milk-white colour, passing sometimes into greyish and reddish-white ; 
 short four-sided prisms, belonging to the -trimetric system, having two of the opposite 
 sides much broader than the other two ; occasionally the lateral edges are truncated, 
 whence results an eight-sided prism belonging to the trimetric system ; lustre splendent, 
 pearly ; foliated fracture ; threefold rectangular cleavage ; cubical fragments ; translu- 
 cent ; scratches calc-spar ; brittle ; specific gravity 2*9. This is the muriacite of some 
 writers. It is doubly refracting. It is said to contain 1 per cent, of sea-salt. It is 
 found at Bex in Switzerland, and Halle in the Tyrol. 6. Siliciferous, or Vulpinite. 
 Massive concretions of a laminated structure ; translucent on the edges ; splendent 
 and brittle : greyish-white, veined with bluish-grey; specific gravity 2*88. It con- 
 tains 8 per cent, silica ; the rest is sulphate of calcium. It is called by statuaries, 
 Marmo bardiglio di Bergamo, and takes a fine polish. It derives its name from 
 Vulpine in Italy, where it accompanies lime. U. 
 
 AlOTIi. A nearly obsolete synonyme of indigo. The same term is also used as 
 a synonyme of PHENYLIMIDE (q. v.) 
 
 ANIIiAlVliC ACID. Syn. of PHENYLAMIC ACID. 
 
 ANXXilX>ES. Syn. of PHENYLAMIDES. 
 
 ANILINE. Syn. of PHENYLAMINE. 
 
 ANXlVXAIiXSATION. The process or series of processes by which food is con- 
 verted into the constituents of the animal body (see DIGESTION and NUTRITION). The 
 same term is used in the arts to denote the operation by which vegetable fibres, such 
 as cotton and .flax, are made to unite with albuminous substances. 
 
 ANIME RESIST, improperly called gum-anime. A resinous substance used for 
 fumigation. There are three varieties of it, the East Indian, the "West Indian, and the 
 
 u 4 
 
296 ANIME ANISAMIC ACID. 
 
 brown American. West Indian anime, sometimes called courbaril resin, is the pro- 
 duce of the Hymencea Courbaril, a tree belonging to the order GssalpinctB, growing in 
 the West Indies and in South America ; the other varieties are of unknown origin. 
 The West Indian resin forms yellowish-white transparent, somewhat unctuous tears, 
 or sometimes larger masses ; it is brittle ; of a light pleasant taste, and very agreeable 
 odour; hence its uso in fumigation and in perfuniery. It softens in the mouth, melts 
 easily in the fire, and burns with a bright flame. Specific gravity T028 (Bresson), 
 1*032 (Paoli). Insoluble in water, perfectly soluble in hot alcohol. Cold alcohol 
 dissolves about 54 per cent, of it. The soluble portion is, according to Laurent, 
 identical with the resin of turpentine. The insoluble portion crystallises from 
 boiling alcohol in slender colourless needles, consisting, according to Laurent, of 
 83'6 per cent. C, 11-5 H, and 4'9 0, agreeing with the formula C M H 3 0. According 
 to Filhol, the resin of Hi/mcn(ga Courbaril is nearly insoluble in cold absolute alcohol, 
 melts at 100 C, and contains 85 '3 per cent, carbon, 11 -5 hydrogen, and 3-2 oxygen. 
 
 Brown American anime softens in the mouth, and dissolves completely in cold 
 alcohol; specific gravity 1'0781 (Paoli). Oriental anime, which, according to Gui- 
 boust, is no longer met with in commerce, is likewise perfectly soluble in cold alcohol, 
 has a density of 1*027, and appears to consist of two resins, differing in melting 
 point (Paoli, Trommsdorff' s Journ. Bd. ix. St. 1; s. 40, 61; G-uiboust, Kev. Scient. 
 xvi. 177; Laurent, Ann. Ch. Phys. [2] Ixvi. 315; Gerhardt, Traite", iii. 669; 
 Filhol, J. Pharm. [3] i. 301, 507.) 
 
 There is some confusion respecting the use of the word anime, the French designating 
 copal as rcsinc anime ; and denoting the West Indian anime or courbaril resin, by the 
 term Copal or anime, tcndre, 
 
 ATCIRIIWE. An organic base obtained, together with three others, odorine, 
 ammoline, and olanine, from bone-oil (Oleum animale Dippclii\ by Unverdorben in 
 1826 (Pogg. Ann. xi. 59 and 67). None of these bases were prepared by Unverdorben 
 in a state of purity. Odorine was afterwards obtained pure, and more exactly inves- 
 tigated under the name of picoline, by Anderson, who showed that it is isomeric with 
 aniline, C 6 H 7 N. The other three bases, which were less volatile than odorine, were 
 probably mixtures of the homologous bases lutidinc, C 7 H 9 N, and collidine, C 8 H n N, 
 together with other substances. (See Grm. xi. 273.) 
 
 AN I OTT (from aviov, that which goes up). A term used by Faraday to denote the 
 element of an electrolyte, which is eliminated at the positive pole or anode ; the other 
 element, which is eliminated at the negative pole or kathode, being called a kation 
 (KCLTIOV, that which goes down). To understand these terms, we must suppose the 
 decomposing body to be so placed that the current (of positive electricity) passing 
 through it, shall be parallel to, and in the same direction with, that which is supposed 
 to exist in the earth, viz. from east to west, or in the direction of the sun's diurnal 
 motion. The positive pole or electrode will then be towards the east. (Faraday's 
 Experimental Researches in Electricity, vol i. p, 196.) 
 
 ANISAMIC ACID. C 8 H fl N0 3 . (Zinin, Ann. Ch. Pharm. xcii. 327.) Ob- 
 tained by passing hydrosulphuric acid into a mixture of nitranisic acid with 8 pts. 
 of alcoholic ammonia. After twelve hours, when the acid is dissolved, the whole is 
 boiled, with occasional addition of water, till all the alcohol is driven off; it is then 
 filtered from the separated sulphur, and mixed with acetic acid, which precipitates 
 anisamic acid in long brown needles: they are obtained colourless by solution in water 
 and treatment with animal charcoal. It forms thin, brilliant, four-sided prisms, which 
 dissolve but slightly even in boiling water, or in ether, but are readily soluble in alcohol. 
 Hydrochloric and boiling acetic acid dissolve it unchanged ; its solution in dilute nitric 
 acid reddens on long boiling, and by cooling deposits brown flakes and a white pulveru- 
 lent substance. It melts at 180 C., and is decomposed at a higher temperature. The only 
 anisamate that has been analysed is the silver-salt, C 8 H 8 AgN0 3 : it is a curdy precipitate, 
 insoluble in water, readily soluble in ammonia and acids ; in the dry state, it may be 
 heated to 120 C. without decomposition, but turns brown when boiled with water. 
 The ammonium-salt is very soluble, and crystallises with difficulty in four-sided 
 tables; its aqueous solution is partially decomposed by boiling, ammonia being evolyed, 
 and the acid crystallising out on cooling. The lead and cadmium-salts are white 
 precipitates. An aqueous solution of anisamic acid does not precipitate lime- or 
 baryta-water, or silver-salts. With ammoniacal sulphate of copper, it gives, in the 
 cold, a light blue flocculent precipitate, which, on boiling, becomes pulverulent, and of 
 a cinnamon colour. 
 
 The mode of formation of anisamic from anisic acid being analogous to that of oxy? 
 benzamic acid from benzoic acid, it should perhaps be regarded as oxyanisamic acid, 
 
 H '')N 
 
 (OTTO) jg, K T. 0. 
 
ANISAMINES ANISE, OIL OF. 297 
 
 H 2 /( ) N 
 
 ANXSAMXDZ:. C S H 9 N0 2 [or, rather, anisamic add, (CHOKm^ (C all ours, 
 
 H ) 
 
 Ann. Ch. Phys. [3] xxii. 353.) Obtained by treating chloride of anisyl with dry am- 
 monia, whereupon heat is evolved, and the mixture becomes a solid mass of anisamide, 
 which is soluble in alcohol, whence it crystallises by spontaneous evaporation in 
 large prisms. It is also formed by the action of ammonia on anisate of ethyl in a 
 closed vessel. F. T. C. 
 
 (Cannizzaro, Compt. rend. 1.1100). These bases are pro- 
 
 duced by the action of strong alcoholic ammonia on the chlorhydrin of anisic alcohol 
 (C 8 H"OC1) : 
 
 C 8 H 9 OC1 + NH 3 = C 8 HON + HC1. 
 
 Anisamine. 
 
 2C 8 H 9 OC1 + NH S = C 18 H 19 2 N + 2HC1. 
 DLuiisamine. 
 
 The resulting mass is freed from sal-ammoniac by digestion in water, then dissolved 
 in alcohol, and the residue obtained by evaporating the alcoholic solution to dryness, 
 consists, after washing with ether, of a mixture of the hydrochlorates of the two 
 bases. These hydrochlorates are separated by water, the anisamine -salt being much 
 the more soluble of the two ; and the bases are obtained in the free state by adding 
 ammonia or potash to the solutions of the hydrochlorates, then agitating with ether, 
 and evaporating the ethereal solution. 
 
 Anisamine crystallises in small needles, soluble in water, alcohol, and ether, and 
 melting with colouration above 100 C. Dianisamine forms at first a thick oil, 
 which, after a few days, crystallises in white laminae. It is soluble in alcohol and in 
 ether; less soluble in water than anisamine. It melts and solidifies between 32 
 and 33 C. 
 
 Both these alkaloids are strong bases. The chloroplatinate of anisamine, 
 C 8 H u ON.HCl.PtCP, crystallises in small gold-yeUow laminse. The chloroplatinate 
 of dianisamine, C 16 H 19 2 N,HCl.PtCl 2 + H 2 is precipitated as a brown oily liquid, 
 gradually changing to a mass of yellow needles. 
 
 The constitution of these bases may be viewed in two different ways. If anisic 
 alcohol be regarded as monatomic = 8 H 9 O.H.O, the bases then appear as ordinary 
 amines, containing the radicle C 8 H 9 0, viz. : 
 
 ( "FT 2 ( TT 
 
 Anisamine = ^mwi Dianisamine 
 
 but if we suppose anisic alcohol to be diatomic = (C 8 H 8 )".H 2 .0 2 , then the bases must 
 be regarded as hydoramines (p. 197), viz. : 
 
 ( T 
 
 = Nj /r 
 
 )".H 2 .0 2 , 
 
 famine . , Dianisamme = 
 
 ANXSANXXiXDE. See PHENYiANisAHTDE, under PHENYLAMINE. 
 
 ArilSE, Oil. OP. Essence d'anis. Anisbl. The name given to the essential 
 oil which is obtained by distillation with water from the seeds of the common anise 
 (Pimpinella anisum}, and the China or star anise (Illicium anisatum}. (According to 
 Hees, 20 Ib. of seeds yield 5J oz. oil.) This oil contains an. oxygenated principle, 
 which, by the action of oxidising agents, is converted into hydride of anisyl. The 
 same principle is found in the oils extracted from fennel (Anethum fceniculum}, and 
 tarragon (Artemisia Dracunculus). All these oils may, therefore, be conveniently 
 described in the same article, though they differ slightly in their physical properties. 
 
 1. Oil of anise and of fennel is a neutral, yellowish, somewhat syrupy liquid, 
 possessing a peculiar aromatic smell and taste. Its specific gravity varies from 0-977 
 to 0-991. It is soluble in all proportions in cold alcohol of specific gravity 0'806, and in 
 2-4 pts. alcohol of specific gravity 0'84 at 25 C. It appears to consist of two distinct oils, 
 one of which solidifies at temperatures below 10, while the other remains fluid at all 
 temperatures. Scarcely anything is known of the latter of these oils ; according to 
 Gerhardt (Trait, iii. 352 ct scq.) it is isomeric with oil of turpentine. The former, 
 which is generally known as anethol or anise-camphor, has been examined by 
 C ah ours (Ann. Ch. Phys. [3] iii. 274). The proportion of these two constituents 
 varies in different specimens of the commercial oil ; but generally the camphor composes 
 f of the whole. The crude oil absorbs oxygen when exposed to the air, becomes more 
 syrupy, and finally loses the property of solidifying by cold. In order to obtain the 
 camphor in a state of purity, it is freed from the liquid oil by pressure between 
 folds of filtering paper, and repeatedly crystallised from alcohol of specific gravity 0'85. 
 It crystallises in soft, white, lustrous laminse, of specific gravity 1-014, having a smell 
 similar to, but weaker" and more agreeable than, that of the crude oil. It is very 
 
298 ANISE, OIL OF. 
 
 f rial ile, especially at 0C. ; melts at 18 C., and at 222 boils and volatilises com- 
 pletely, but not without slight coloration. Its formula is C IO H 12 0. Its vapour-density, 
 taken at 338 C., is 5*19 ; at lower temperatures, its density is higher. It is not affected 
 by exposure to the air in the solid state ; but, if kept in a state of fusion, it gradually 
 ceases to solidify on cooling, and finally resinifies completely. Nitric acid converts 
 it into hydride of anisyl, anisic or nitranisic acid, and oxalic acid ; the products vary 
 Avith the concentration of the acid. Generally a yellow resinous substance is also formed, 
 to which Cahours gives the name nitraniside, and the formula C 10 H 10 (N0 2 ) 2 (?). 
 This is a very insoluble substance, which melts at about 100 C., and is completely de- 
 composed by distillation ; when treated with a strong solution of potash, it gives off 
 ammonia abundantly, and is converted into a black substance, which Cahours calls 
 mclan isic acid. Under certain circumstances, the action of dilute nitric acid produces 
 an acid containing 10 atoms carbon (see ANISOIC ACID). When distilled with sulphuric 
 acid and bichromate of potassium, oil of anise yields anisic and acetic acids. (Hemp el, 
 Ann. Ch. Phann. lix. 104.) 
 
 Strong boiling solutions of caustic alkalis do not attack oil of anise ; but when it is 
 heated with potash-lime in a sealed tube to the boiling point of the oil, a peculiar 
 acid is formed, which appears to be isomeric with cuminic acid. (Gerhardt.) 
 
 Anise-camphor treated with acid sulphite of sodium, is resolved into methyl and 
 hydride of anisyl, C'H 12 + H 2 = 2CH 3 + C 8 H 8 2 . (Stadeler and Wachter 
 Ann. Ch. Pharm. cxvi. 172.) 
 
 Anise-camphor absorbs hydrochloric acid gas abundantly, forming a liquid com- 
 pound, C'H 12 O.HC1, which contains 19 '8 per cent, chlorine. It absorbs chlorine 
 rapidly, with evolution of heat and vapours of hydrochloric acid, forming substitution- 
 products, in which the number of atoms of hydrogen replaced by chlorine varies with 
 the duration of the action of the gas. The trichlorinated compound (chloranisal} 
 C'H 9 C1 3 0, is a syrupy liquid, which is completely decomposed by distillation, and 
 from which, by the further action of chlorine, aided by heat, a still higher chlorine 
 compound may be obtained. Oil of anise treated with pentachloride of phosphorus, 
 yields a liquid boiling at a high temperature, probably C 10 H 12 C1 2 . (Aelsmann and 
 Kraut, J. pr. Chem. Ixxvii. 490.) 
 
 When anhydrous bromine is gradually added to anise-camphor, heat and hydro- 
 bromic acid are evolved, and the whole becomes liquid, and finally, when the bromine 
 is in excess, solidifies after a time ; it is then washed with cold ether, and recrys- 
 tallised from boiling ether. The bromanisal, C l H 9 Br 3 0, thus obtained forms large 
 lustrous crystals, insoluble in water, very slightly soluble in alcohol; it is decomposed by 
 heat, decomposition commencing at about 100 C. ; it is not further acted on by bromine. 
 
 When oil of anise is treated with perchloride of tin or trichloride of antimony, 
 it thickens into a red pitchy mass, which, when boiled with water, deposits a white 
 substance, apparently isomeric with anise-camphor. Cahours calls it anisoin. It 
 is also formed when oil of anise is gradually mixed with 1^ pts. strong sulphuric 
 acid, and the resulting resinous mass treated with water. It is purified by solution in 
 ether, and reprecipitation by dilute alcohol. Thus obtained, it is a white, inodorous 
 solid which fuses a little above 100C., and, when further heated, burns with a brilliant 
 flame and an aromatic smell ; it is heavier than water ; insoluble in water, almost 
 insoluble in alcohol, even on heating ; more soluble in ether and volatile oils. It is 
 soluble in strong sulphuric acid, forming a red solution, whence it is reprecipitated by 
 water. It is not attacked by a boiling solution of caustic potash. When distilled, it 
 partly volatilises unchanged and partly passes over as an isomeric oil. When cry- 
 stallised from its ethereal solution, it forms very small white needles. The substance 
 obtained by Will (Ann. Ch. Pharm. Ixv. 230), by dropping oil of anise into a strong 
 solution of iodide of potassium saturated with iodine, and treating the resulting magma 
 with 6 or 8 times its volume of alcohol, is, according to Gerhardt, whose statement 
 is confirmed by the recent experiments of Aelsmann and Kraiit (loc. cit.}, identical 
 with anisoin. This substance, when treated with chlorine, yields a chlorine substi- 
 tution-compound. Anisoin is also produced by treating oil of anise with chloride of 
 benzoyl. (Aelsmann and Kraut.) 
 
 When anise-camphor is distilled with chloride of zinc, a volatile oil passes over, 
 which after a time generally deposits crystals, volatile without decomposition and 
 not ^melting at 100^C. Both oil and crystals have the same composition as the 
 original camphor; and the vapour-density of the oil is the same as that of the 
 camphor. The oil is readily soluble in strong sulphuric acid, forming a fine crimson 
 solution ; the addition of water destroys the colour, but does not precipitate anything. 
 By saturating the aqueous solution with carbonate of barium, a gummy salt is ob- 
 tained, whose solution gives a dark violet colour with ferric salts ; both acids and 
 alkalis destroy the colour (Gerhardt). The same product is obtained when oil of 
 anise or anise-camphor is treated with 3 4 pts. concentrated sulphuric acid, water 
 
ANISHYDRAMIDE. 299 
 
 added, the oil which separates filtered off, and the aqueous filtrate saturated with 
 barytic carbonate. It appears to be identical with Laurent's sulphodraconate of 
 barium, obtained by him from oil of tarragon. 
 
 2. Oil of Tarragon (Laurent, Kevue Scient. x. 6) consists mainly of a camphor 
 isomeric with that of anise, and behaving in the same manner with nitric and sul- 
 phuric acids and metallic chlorides. The proportion of liquid oil in this essence 
 is very small : hence the crude oil does not boil below about 200 C., and the boiling 
 point gradually rises to 206, where it remains stationary. Its specific gravity is 
 0-945 ; vapour-density 6-157 at 230. When treated with chlorine, it evolves heat and, 
 acid vapours, and gradually becomes more syrupy ; one of the products thtis obtained 
 (chloride of draconyl}, of about the consistence of turpentine, gave on analysis per- 
 centages which seem to indicate the formula C 10 H 10 Cr 2 O.Cl 2 . When treated with 
 alcoholic potash, this substance yielded a thick oil (chlorodraconyl) containing 42*5 
 per cent, carbon and 3*4 per cent, hydrogen. 
 
 3. Oil of Bitter Fennel (Cahours, loc. tit). This essence is composed of two oils, 
 the less volatile of which can readily be obtained pure by fractional distillation. Its 
 composition is the same as. that of anise-camphor ; but it does not solidify at 10 C. Its 
 specific gravity is somewhat less than that of water ; it boils at 225 C. Treated with 
 nitric acid, it behaves like anise-camphor ; with bromine it gives a liquid viscous pro- 
 duct, which is very difficult to purify. The more volatile oil appears to have the same 
 composition as oil of turpentine. It boils about 190 C. When a stream of nitric oxide is 
 led into it, it becomes thick and turbid, and on addition of alcohol of specific gravity 0-80, 
 yields a white, silky precipitate, which is purified by repeated washing with alcohol. This 
 substance, which forms fine crystalline needles, contains 3C 10 H 16 ,8NO. It is discohmred 
 when heated to 100 C., and at a higher temperature is entirely decomposed. It is scarcely 
 soluble in alcohol of specific gravity 0'80, rather more in absolute alcohol, still more 
 in ether ; soluble in strong caustic potash, and reprecipitated by acids. When heated 
 with caustic soda, it yields ammonia, an oil smelling like petroleum, and a gas which 
 attacks the eyes. When treated with sulphydrate of ammonium in the cold, and then 
 by an acid, it gives a precipitate which explodes slightly when heated ; the filtrate 
 gives an abundant blue precipitate with ferric salts. It dissolves in boiling sulp- 
 hydrate of ammonium, forming a brown solution, and depositing sulphur, while a 
 strong smell of oil of bitter-almonds is evolved. It is scarcely attacked by boiling 
 hyposulphite of sodium. (Chiozza.) F. T. C. 
 
 ATCriSHYDRAnxXDE. Hydrurc d'azoanisyl. C 24 H 24 N 2 3 . (Cahours, Ann. Ch. 
 Phys. [3] xiv. 487.) The action of ammonia upon hydride of anisyl is analogous to 
 that which it exerts upon the hydrates of benzoyl and salicyl, a hydramide being 
 formed : 
 
 3C 8 H 8 2 + 2NH 3 = C 24 H 24 N 2 3 + 3H 2 
 
 Hydride of Anishydra- 
 
 anisyl. mide. 
 
 This substance is obtained by abandoning for some time a mixture of 1 vol. hydride 
 of anisyl, and 4 5 vols. of a saturated aqueous solution of ammonia, in, a closed 
 vessel, when shining crystals of anishydramide gradually form, until, after some 
 weeks, the whole becomes a semi-solid mass. The crystals are then freed from ad- 
 hering liquid by pressure between folds of filtering paper, and dried. They are hard, 
 snow-white prisms, very easily powdered; insoluble in water, soluble in boiling 
 alcohol or ether, and in warm concentrated hydrochloric acid, whence they recry- 
 stallise on cooling. They melt at about 120 G. When anishydramide is acted on by 
 sulphide of ammonium, a white powder is obtained, which Cahours (Compt. rend, 
 xxv. 458) calls thianisiol, andG-erhardt (Traite, iii. 360) hydride of sulphanisyl. Its 
 formula is C"H 8 SO. 
 
 For the probable constitution of anishydramide, see HYDKAMIDES in art. AMIDES, 
 p. 177. 
 
 When anishydramide is kept for two hours at a temperature between 165 
 and 170 C., it is converted into an isomeric alkaloid, to which the name anisine has 
 been given (Bertagnini, Ann. Ch. Pharm. Ixxxviii. 128). In order to obtain 
 this substance in a state of purity, it is dissolved in boiling alcohol, and hydrochloric 
 acid added to the solution, when the hydrochlorate separates out in crystals. These 
 are freed from the mother- liquor, decomposed by potash or ammonia, and the free base is 
 recrystallised from alcohol. Thus obtained, anisine forms colourless transparent prisms, 
 scarcely soluble either in hot or cold water, slightly soluble in ether, readily in alcohol. 
 Its solution has a strong alkaline reaction and a bitter taste. Anisine forms crystallisable 
 salts with acids. The hydrochlorate, C 24 H 24 N 2 3 .HC1, crystallises in colourless brilliant 
 needles, slightly soluble in water, readily in alcohol. "When dried at the ordinary 
 temperature, they contain 4C"H W N 2 8 .HC1 + 9IFO; they give off water at 100 C. 
 
300 ANISIC ACID. 
 
 The chloroplatinate, C M H w N*O a ,HCl,PtCl 8 , obtained by adding bichloride of platinum to 
 the hydrochlorate, forms brilliant orange-coloured scales, slightly soluble in alcohol. 
 
 F. T. C. 
 
 ANISIC ACID. Hydrate of anisyl. Draconic acid, &c. C 8 H 8 3 = (C 8 H 6 0)".H 2 .0 2 . 
 (Cahours, Ann. Ch. Phys. [3] ii. 287; xiv. 483 ; xxiii. 351; xxv. 21 ; xxvii. 439; 
 Laurent, Revue Scient. x. 6, 362; Grerhardt, Ann. Ch. Phys. [3] vii. 292.) This 
 acid, discovered by Cahours in 1841, is a product of the oxidation of anise-cam- 
 phor and of the crude oils of anise, fennel, and tarragon. The acids obtained 
 from these several oils were at first distinguished by different names; but their 
 identity is now clearly established. The first product of the oxidation of these sub- 
 stances is hydride of anisyl, which, by further oxidation, is converted into anisic acid. 
 (See ANISYL, HYDRIDE OF.) 
 
 Cahours prepares anisic acid by boiling oil of anise with nitric acid of specific 
 gravity 1-2 (23 Baume), when a yellow resinous substance (nitraniside) is formed, 
 together with anisic acid, which crystallises from the acid liquid on cooling. The 
 crystals are washed with cold water, and dissolved in ammonia ; the ammonium-salt 
 is repeatedly crystallised till it is colourless, and then decomposed by acetate of lead ; 
 the difficultly soluble lead-salt is washed, and decomposed by sulphuretted hydrogen ; 
 and the anisic acid is dissolved from the sulphide of lead by boiling water, crystallised, 
 and purified (if necessary) by sublimation. 
 
 Laurent's method of preparing it from oil of tarragon is as follows : 1 pt. oil 
 together with a little water, is heated in a large retort, and 3 pts. common nitric acid 
 are added gradually. The mixture thickens by degrees, and is finally converted into 
 a brown, resinous, slightly crystalline mass. This is washed, and extracted with hot 
 dilute ammonia, which dissolves all but a small quantity of a brown substance. The 
 ammoniacal solution is evaporated to a syrup, when it deposits a further portion of 
 the brown substance, which was held in solution by the free ammonia : if the evapora- 
 tion be carried too far, the anisate and nitranisate of ammonium contained in the 
 solution may be partially decomposed. The syrup is mixed with water, boiled, and 
 filtered through animal charcoal ; and the filtrate (neutralised, if acid, by ammonia) 
 is evaporated, when anisate of ammonium crystallises in rhomboidal tables, while the 
 nitranisate remains in the mother-liquor. The anisate is recrystallised two or three 
 times from alcohol, dissolved in a boiling mixture of alcohol and water, and nitric 
 acid added to the hot solution, which, on cooling, deposits crystals of anisic acid. 
 These are further purified by recrystallisation from boiling alcohol, and, if necessary, 
 by sublimation. 
 
 Anisic acid may also be prepared by dropping hydride of anisyl upon fused caustic 
 potash. A soft resinous mass is obtained, which, when dissolved in water and 
 saturated with hydrochloric acid, deposits crystals of anisic acid, which are purified 
 as above. If hydride of anisyl be procurable, this is the most advantageous method, 
 since the formation of nitranisic acid is entirely avoided. (Handwb.) 
 
 Anisic acid crystallises in brilliant colourless prisms, belonging to the monoclinic 
 system, often of considerable size, with angles of 114 and 66. The acute edges are 
 mostly truncated ; the base is replaced by two principal and three smaller faces. It 
 has no taste or smell ; is tolerably soluble in hot, but scarcely in cold, water ; readily 
 soluble in alcohol or ether, especially on boiling; its solution reddens litmus feebly. 
 It fuses at 175 C, and solidifies on cooling to a crystalline mass; at a higher tem- 
 perature it sublimes without decomposition into snow-white needles. 
 
 It is isomeric with salicylate of methyl. 
 
 It is violently attacked by chlorine and bromine (see below, SUBSTITUTION-PRODUCTS). 
 Hot concentrated nitric acid converts it into nitranisic acid. Fuming nitric acid 
 converts it into dinitranisol or trinitranisol (see ANISOL), the product varying with 
 the duration of the reaction and the proportion of the reagants. If heat be applied, 
 a third substance, chrysanisic acid, isomeric with trinitranisol, is simultaneously 
 formed. A mixture of sulphuric and fuming nitric acids converts it into trinitranisol. 
 Perchloride of phosphorus attacks it violently, forming chloride of anisyl, chloride 
 phosphoryl, and hydrochloric acid. When distilled over caustic baryta, it is decom- 
 posed into carbonic anhydride and phenate of methyl (anisol). 
 
 C 8 H"0 3 = CO 2 + C 6 IP(CH 3 )0. 
 
 Anisate s. Anisic acid is usually considered as monobasic ; but it is probably 
 diatomic, like glycollic and lactic acids. The general formula of the anisates is C 8 H 7 MO* 
 (see ANISYL). They are mostly crystallisable : the alkaline and earthy salts are 
 soluble, and the addition of a mineral acid separates anisic acid from their solutions. 
 
 The aluminium-salt crystallises slowly in fine needles, when a dilute solution of 
 alum is added to anisate of ammonium. 
 
 The ammonium-salt, C*H 7 (NH')0 8 , is very soluble, and crystallises in large rhombic 
 
ANISIC ACID. 301 
 
 tables, the angles of whose base are 84 and 96. Exposed to the air, they become 
 opaque : heated to 99 C. in vacuo, they lose ammonia, pure anisic acid being left 
 behind. 
 
 The barium-salt, when prepared directly by boiling anisic acid with baryta, crys- 
 tallises first in needles, and then in rhomboidal scales. Chloride of barium does not 
 precipitate anisate of ammonium immediately, but after some time, a difficultly soluble 
 crystalline precipitate forms. 
 
 The calcium-salt. Chloride of calcium precipitates anisate of ammonium imme- 
 diately ; if the solutions are dilute, it crystallises in groups of needles. 
 
 The copper-salt is a bluish-white precipitate. 
 
 The ferric-salt is a yellow precipitate, composed of microscopic needles. 
 
 The lead-salt is a white precipitate, soluble in hot water, whence it crystallises on 
 cooling in shining scales, which retain | atom of water after drying at 120. 
 
 The magnesium-salt is soluble. 
 
 The manganese-salt crystallises slowly from a mixture of sulphate of manganese and 
 anisate of ammonium. 
 
 The mercuric, mercurous, and zinc-salts are white precipitates ; the first crystallises 
 from hot water in microscopic needles. 
 
 The potassium-salt crystallises in rhomboidal or hexagonal tables ; the sodium-salt 
 in needles. 
 
 The silver-salt is a white precipitate, crystallising from hot water in fine needles, or 
 pearly scales. 
 
 The strontium-salt crystallises gradually in small hexagonal or rectangular laminae, 
 from a mixture of chloride of strontium and anisate of ammonium. 
 
 ANISIC ETHERS. (Cahours, Ann. Ch. Phys. [3] xiv. 492.) 
 
 Anisate of Methyl, C 9 H 10 3 = C 8 H 7 (CH 3 )0 3 . A mixture of 2 pts. anhydrous 
 wood-spirit,. 1 pt. anisic acid, and 1 pt. strong sulphuric acid, assumes an intense 
 carmine-red colour ; on the application of a gentle heat, wood-spirit first passes over, 
 and then a heavy oil, which solidifies in the receiver. This is anisate of methyl. It 
 is purified by washing with hot sodic carbonate, and with water, and recrystallisation 
 from alcohol or ether. Thus prepared, it forms large, white, shining scales, which 
 melt about 47 C., and solidify on cooling to a crystalline mass ; at a higher temperature 
 it distils undecomposed. It has a faint smell, resembling that of oil of anise, and 
 a burning taste. It is insoluble in hot or cold water ; readily soluble in alcohol or 
 ether, especially on boiling. Unlike salicylate of methyl, it does not combine with 
 potash or soda ; but, when boiled with a strong solution of either alkali, is decomposed 
 into methylic alcohol and an alkaline anisate. Aqueous ammonia does not dissolve 
 it, but gradually decomposes it into methylic alcohol and anisamide, the latter of 
 which crystallises out. Bromine, chlorine, and fuming nitric acid attack it violently, 
 forming respectively the methyl-salts of the corresponding substitution-acid. 
 
 Anisate of Ethyl C 10 H 12 3 = C 8 H 7 (C 2 IP)0 3 . When a solution of 1 pt. anisic 
 acid in about 6 pts. absolute alcohol is saturated at about 60 C. with hydrochloric acid 
 gas, a fuming liquid is obtained, whence water precipitates only anisic acid. On 
 distilling this liqiiid chloride, hydrate, and finally anisate of ethyl pass over; and on 
 adding water to the distillate, the latter product separates out as a heavy oil, which 
 is washed with sodic carbonate, dried over chloride of calcium, and rectified over 
 oxide of lead. It is a colourless oily liquid, heavier than water, with a smell like 
 that of oil of anise, and a warm aromatic taste. It boils between 250 C. and 255, is 
 insoluble in water, readily soluble in alcohol and ether. It may be kept unchanged 
 in closed vessels ; but, when exposed to the air, it gradually becomes acid. Its decom- 
 positions are precisely analogous to those of the methyl-salt. 
 
 Substitution-derivatives of Anisic Acid. 
 
 BROMANISICACID. Bromodraconcsic acid (Laurent). C 8 H 7 Br0 3 . When 
 
 powdered anisic acid is treated with bromine, heat is evolved, together with abundance 
 of hydrobromic acid ; the product is washed with water, and crystallised from boiling 
 alcohol. Bromanisic acid is thus obtained in white shining needles, slightly soluble 
 in hot water, readily in hot alcohol or ether. It melts at 205 C., and sublimes in 
 iridescent laminae. When distilled with lime, it yields carbonic anhydride and bro- 
 manisol. The alkaline bromanisates are soluble; the potassium and sodium-salts 
 yield bromanisol by dry distillation. In their solution, lead-, silver-, barium-, strontium-, 
 and calcium-salts give white precipitates ; the last three are not quite insoluble, but 
 crystallise gradually from dilute solutions. 
 
 Bromanisate of Methyl, C 8 H 6 (CH 3 )Br0 3 , is obtained by dropping bromine on the 
 anisate, and treating the yellowish-red product as in the case of bromanisic acid. Also 
 
302 ANISIC ACID. 
 
 in the same manner as the anisate, bromanisic being substituted for anisic acid. The 
 mixture is boiled in a water-bath for a quarter of an hour, and water added, when the 
 bromanisate separates in flakes, which are washed with dilute ammonia and crys- 
 tallised from hot alcohol. It forms colourless transparent prisms, which melt at a 
 gentle heat : it is insoluble in water ; soluble, especially on heating, in alcohol and 
 wood-spirit; less soluble in ether. By boiling potash it is decomposed like the 
 anisate. 
 
 Bromanisate of Ethyl, C 8 H 6 (C 2 H 5 )Br0 3 , is obtained by the same process as anisate 
 of ethyl, anisic being replaced by bromanisic acid ; or by treating anisate of ethyl with 
 bromine. It is purified in the same way as the methyl-salt It forms long, white, 
 shining needles, insoluble in water, soluble in alcohol or ether : it fuses at a gentle 
 heat, and sublimes undecomposed. It is decomposed by boiling potash, and is not 
 attacked by excess of bromine. 
 
 CHLOBANISIC ACID, C 8 H 7 C10 S , is obtained by passing chlorine over anisic acid 
 in fusion; the product is washed with water, and crystallised from alcohol of 95 
 per cent. It forms fine shining needles, scarcely soluble in water, readily in alcohol 
 or ether. It melts at about 176 C., and may be sublimed without decomposition. It 
 is not acted upon by chlorine, even in sunshine. Strong sulphuric acid dissolves 
 it by aid of gentle heat ; it recrystallises from the solution on cooling, or is at once 
 precipitated by water. When heated with baryta, it is decomposed like anisic acid. 
 The metallic chloranisates resemble the corresponding bromanisates in solubility and 
 general properties. The chloranisates of methyl and ethyl are obtained by submitting 
 the corresponding anisates to the action of dry chlorine ; the latter may also be prepared 
 in a similar way to anisate of ethyl. Both are crystalline compounds, insoluble in 
 water, soluble in alcohol or ether, and decomposed by boiling potash. 
 
 NITRANISIC ACID, C 8 H 7 (N0 2 )0 3 , is formed by the action of strong warm nitric 
 acid on anisic acid. It is usually prepared by boiling oil of anise with nitric acid of 
 specific gravity T33 (36 Baume), until the oily substance which first forms has com- 
 pletely disappeared. The addition of water then precipitates yellowish flakes of impure 
 nitranisic acid. This is purified by washing with water, dissolving in ammonia, re- 
 crystallising the ammonium-salt till it is colourless, dissolving it in water, precipitating 
 the acid by nitric or hydrochloric acid, and washing it repeatedly with water. It is 
 also formed in Laurent's process for preparing anisic acid from oil of tarragon, remain- 
 ing in the ammoniacal mother-liquor whence anisate of ammonium has crystallised 
 out. It is obtained thence by adding nitric acid, washing the precipitate, and boiling 
 it for half an hour with nitric acid ; the acid solution deposits on cooling short prisms 
 of nitranisic acid, which are washed with water, and crystallised from hot alcohol. 
 Nitranisic acid crystallises in small shining needles, of a slight yellow tinge, without 
 taste or smell. It is scarcely soluble even in hot water ; readily in alcohol or ether. 
 It melts between 175 and 180. When carefully heated further, it partly sublimes, 
 partly blackens, and is decomposed ; if heated suddenly, it decomposes at once, with 
 evolution of light. It is not attacked by chlorine, bromine, or strong nitric acid ; by 
 fuming nitric acid, it is acted on in the same way as anisic acid. When heated with 
 perchloride of phosphorus, it yields a dark yellow oil, with a very high boiling point, 
 which is probably chloride of nitranisyl, C 8 H 6 (N0 2 )0 2 ,C1 (C a hours). An alcoholic 
 solution of sulphide of ammonium converts it into anisamic acid (p. 291). According 
 to Laurent (loc. cit.} nit-ranisic acid combines, atom for atom, with anisic, chloranisic, 
 and bromanisic acids, forming peculiar dibasic acids. 
 
 The alkaline nitranisatcs are soluble and crystallisable : the ammonium-salt crys- 
 tallises in fine needles, grouped in spheres ; it is soluble in alcohol. The alkaline- 
 earthy nitranisates are difficultly soluble; those of the heavy metals generally 
 insoluble. 
 
 Nitranisate of methyl is prepared by a process analogous to that described in the 
 case of anisate of methyl ; or by dissolving anisate of methyl in fuming nitric acid, 
 adding water, and crystallising the precipitate from alcohol. It forms beautiful 
 large shining tables of a yellowish hue. It is insoluble in water ; readily soluble in 
 hot alcohol or wood-spirit, whence it separates almost completely on cooling. It melts 
 at about 100 C., and sublimes undecomposed. 
 
 Nitranisate of ethyl is prepared either by dissolving anisate of ethyl in an equal 
 volume of fuming nitric acid, or by a process analogous to that described in the case 
 of anisate of methyl. In the latter case, the mixture must be kept at a temperature of 
 60 70 C., while it is saturated with hydrochloric acid. The compound is precipitated 
 ty water, washed with dilute ammonia, and crystallised from alcohol. It exactly 
 resembles the methyl-salt in appearance, and solubility in water and alcohol, and 
 melts between 98 and 100 C. Strong sulphuric acid dissolves it in the cold, more 
 readily on heating; it partly recrystallises as the solution cools, and is completely 
 precipitated by water. Bromine exerts no action upon it. 
 
ANISIC ALCOHOL. 303 
 
 Trinitranisic Acid, C 8 H 5 (N0 2 ) S 8 , is obtained by treating anisic acid in the 
 cold with a mixture of fuming nitric and fuming sulphuric acid, and diluting the 
 mixture with 8 to 10 times its volume of water. It forms very beautiful salts with 
 the alkalis, especially with ammonia and potash. 
 
 SULPHANISIC ACID, C 8 H 8 3 ,S0 3 . (Zervas, Ann. Ch. Pharm. ciii. 339 ; Lim- 
 pricht, Gm. Handb. xiii. 128.) Obtained by heating anisic acid with common 
 sulphuric acid to 110 C. or with fuming sulphitric acid to 100, diluting the mixture 
 with water, adding carbonate of lead, filtering at the boiling .heat, and boiling the 
 insoluble residue with water as long as the filtered liquid yields crystals of the lead- 
 salt on cooling. These, when decomposed by sulphuretted hydrogen, yield the acid 
 (Zervas). Limpricht treats anisic acid with sulphuric anhydride. 
 
 Sulphanisic acid, obtained by slow evaporation of the aqueous solution, forms 
 needles which are permanent in the air, and give off 6'9 per cent. (1 at.) water at 
 100 C., and suffer no further decomposition below 170. The aqueous solution may be 
 boiled without decomposition. 
 
 Sulphanisic acid is dibasic. The sulphanisates of ammonium, potassium, and 
 sodium crystallise readily, the first in long slender needles. The barium-salt, 
 C 8 H 6 Ba 2 3 .S0 3 + 8H 2 0, obtained by saturating the acid with carbonate of barium, 
 forms fine crystals, which, after drying over sulphuric acid, give off 16-9 per cent. 
 (8 at.) water at 180 C. It dissolves easily in water, and is precipitated by alcohol. 
 The magnesium-salt forms very soluble needles. The normal lead-salt, C 8 H 6 Pb 2 3 .S0 3 
 + 8H 2 6, forms beautiful needles, which give off their water at 180 C. The acid 
 lead-salt, C 8 H 7 Pb0 3 .S0 3 + H 2 0, forms nodular crystals ; easily soluble in water. 
 
 The silver-salt forms nodular crystals, sparingly soluble in water. According to 
 Zervas, the solubility of the barium and lead-salts is diminished by repeated 
 crystallisation. F. T. C. 
 
 ANISIC ALCOHOL. Hydrate of Anisalyl, C 8 H I0 2 = (OTO.H.O. (Can- 
 nizzaro and Bertagnini, Ann. Ch. Pharm. xcviii. 188.) Formed from hydride 
 of anisyl in the same way as benzoic alcohol from hydride of benzoyl. When 
 a solution of pure hydride of anisyl in an equal volume of alcohol is mixed with 
 three times its bulk of alcoholic potash of about 7 Beaume (specific gravity 
 1-052), a slight evolution of heat takes place, and anisic alcohol and anisate 
 of potassium are formed, the latter in such quantity that the mixture shortly 
 becomes a crystalline pulp. (2C 8 H 8 2 + KHO = C 8 H 7 K0 3 + C 8 H I0 2 .) After 10 
 or 12 hours, the alcohol is distilled off in a water-bath, and the residue is suspended in 
 water, and extracted with hot ether. On evaporating the ethereal solution, a brown 
 oil is obtained, and on distilling the oil, anisic alcohol passes over at about 260C., as 
 a colourless liquid, which crystallises on cooling. This product generally contains some 
 hydride of anisyl, which may be detected by agitating it with a concentrated solution 
 of acid sulphite of sodium (see ANISYL, HYDRIDE OF). To purify it, it is treated again 
 with a small quantity of alcoholic potash, distilled in carbonic anhydride, and the 
 crystalline distillate pressed between filter-paper. 
 
 Anisic alcohol crystallises in hard, white, shining needles. It distils undecomposed 
 between 248 and 250 C., and melts at 23, when anhydrous, but at much lower 
 temperatures when moist. It is heavier than water, has a faint spirituous, sweetish 
 smell, and a burning taste like that of oil of anise. At ordinary temperatures, it 
 remains unaltered in the air ; but when heated nearly to its boiling point it, absorbs 
 oxygen, and is converted into hydride of anisyl. Oxidising agents (as platinum- 
 black, nitric acid, &c.) convert it, first into hydride of anisyl, then into anisic acid. 
 Potassium dissolves in it with evolution of hydrogen. Sulphuric acid, even when 
 moderately concentrated, or phosphoric anhydride, converts it into a resinous mass. 
 Heated with chloride of zinc, it yields water, and an oily liquid, which solidifies on 
 cooling into a hard, transparent, vitreous mass, which melts at 100 C., and is insoluble 
 in water and alcohol, but soluble in bisulphide of carbon. 
 
 When treated with hydrochloric acid gas, it forms water and a colourless liquid, 
 having a fruity smell and a burning taste. This substance is its hydrochloric ether, 
 or chloride of anisalyl, C 8 H 9 O.C1, and is decomposed by alcoholic ammonia yielding 
 chloride of ammonium, and the hydrochlorates of anisamine and dianisamine (p. 297). 
 
 If, as is probable from its analogy to salicylic acid, anisic acid be regarded as 
 dibasic, anisic alcohol becomes diatomic, (C 8 H 8 ).H 2 .0 2 ; and chloride of anisalyl will be 
 
 ( TTO 
 C 8 H 8 < i , analogous to glycolic chlorhydrin. F. T. C. 
 
 ANISIC ANHYDRIDE. C 16 H I4 5 = C 8 H 7 2 .C 8 H 7 2 .0. (Pisani, Ann. Ch. 
 Pharm. cii. 284.) Formed by the action of oxychloride of phosphorus on dry anisate of 
 sodium ; the mass is washed with water, and the insoluble residue crystallised from 
 ether. It forms silky needles, soluble in alcohol or ether, insoluble in water or 
 
304 ANISIDIXE. 
 
 aqueous alkalis ; it melts at 99C., and distils at a higher temperature. By long 
 boiling with water or aqueous alkalis, it is converted into anisic acid. F. T. C. 
 
 (Mi-thylphenidine, Gerh.) C 7 H 9 NO = N.C 7 H 7 O.H 2 . (C ah ours. 
 Ann. Ch. Phys. [3] xxvii. 443.) The action of sulphide of ammonium on the nitro- 
 derivative of anisol gives rise to the formation of peculiar organic bases. Anisidine is 
 obtained by dissolving nitranisol in an alcoholic solution of sulphide of ammonium, 
 evaporating at a gentle heat to a quarter of its volume, adding a slight excess of 
 hydrochloric acid to the brown residue, separating the sulphur by addition of water, 
 and filtering. The yellow-brown filtrate deposits on evaporation, needles of hydro- 
 chlorate of anisidine, which are dried with filter paper and distilled with a strong 
 solution of potash, when anisidine passes over with the aqueous vapour in the form of 
 an oil, which solidifies on cooling. 
 
 The properties of anisidine but are imperfectly known. It combines with acids, form- 
 ing salts. The hydrochlorate forms fine colourless needles, soluble in water and alcohol. 
 When a hot concentrated solution of this salt is mixed with a concentrated solution of 
 dichloride of platinum, the chloroplatinate separates on cooling in yellow needles. The 
 nitrate, sulphate, and oxidate are crystallisable. 
 
 The products of the action of sulphide of ammonium on the higher nitro-derivatives 
 of anisol may be regarded as nitro-derivatives of anisidine, though it is not known 
 whether they can be formed by the action of nitric acid on anisidine. 
 
 NITRANISIDINE (Methylnitrophenidine, Gerh.) C 7 H 8 N 2 3 - C 7 H 8 (N0 2 )NO. 
 Prepared by a process similar to that described for anisidine, dinitranisol being substituted 
 for nitranisol. The filtrate is mixed with ammonia, and the precipitate thus formed 
 is washed with water, and crystallised from boiling alcohol. Nitranisidine forms long, 
 garnet-red, shining needles, which are insoluble in cold, soluble in boiling, water ; 
 soluble in boiling alcohol, whence it separates almost entirely on cooling ; also in 
 ether, especially if heated. It melts at a gentle heat, and on cooling forms a radiated 
 mass ; when heated gradually to a higher temperature, it gives off yellow fumes, which 
 condense into yellow needles. Bromine attacks it violently, forming a resinous mass, 
 which has no alkaline properties. Fuming nitric acid decomposes it violently, yielding a 
 viscous mass, insoluble in acids. The chlorides of benzoyl, cinnamyl, cumyl, and anisyl 
 attack it when gently heated, forming hydrochloric acid, and compounds analogous to 
 benzamide, which are described by Cahours under the names of bmzonitranisidc, 
 (J"H 12 N 2 4 = N.C 7 H 5 O.C 7 H 6 (N0 2 )O.H., cinnitraniside, C 16 H 14 N 2 4 , &c. These bodies 
 are obtained pure by successively washing the products of these reactions with water, 
 hydrochloric acid, and dilute potash, and crystallising from boiling alcohol ; they are 
 insoluble in water or in cold alcohol. 
 
 Nitranisidine dissolves readily in acids, and with many of them forms crystalline 
 salts. The hydrochlorate and hydrobromate, when pure, form colourless needles, slightly 
 soluble in cold, readily in boiling, water. The chloroplatinate separates in orange- 
 brown needles from a mixture of hot concentrated solution solutions of the hydro- 
 chlorate and dichloride of platinum. The sulphate forms concentric groups of silky 
 needles, readily soluble in water, especially in water containing sulphuric acid. The 
 nitrate forms large needles, much more soluble in hot than in cold water. 
 
 Dinitranisidine (Mcthyl-dinitrophenidine, Gerh.) C'HTO'O 5 = C 7 H 4 (N0 2 ) 2 NO. 
 Prepared precisely like nitranisidine, trinitranisol being substituted for dinitranisol. 
 When dry, it is an amorphous powder, of a bright red or violet-red colour, according to 
 the concentration of the solution from which it was precipitated. It is almost insoluble 
 in cold water, very slightly in hot water, forming an orange solution : slightly soluble in 
 cold, moderately in hot alcohol, and separates on cooling in violet-black crystals; 
 slightly soluble in hot ether. It meks at a gentle heat, and solidifies on cooling into a 
 radiated, violet-black, crystalline mass. It is much less basic in its properties than the 
 foregoing compound : it forms crystallisable salts with hydrochloric, nitric, and sul- 
 phuric acids, if the acids be employed in excess, but these compounds are decom- 
 posed by water. When heated with fuming nitric acid, it is violently attacked, and 
 yields a yellowish brown resinous mass, which dissolves in potash, forming an intcnsdy 
 brown solution. F. T. C. 
 
 ATJISITJE. See ANISHYDRAMIDE. 
 
 ANISOIC ACID. C'H 18 6 . (Limpricht and Hitter, Ann. Ch. Pharm. xcvii. 
 364.) A product of the oxidation of oil of star-anise (probably also of oil of anise, tar- 
 ragon, fennel, &c.). The oil is heated with nitric acid, of specific gravity 1-2, and the 
 oily layer which sinks to the bottom of the mixture is agitated with a warm solution 
 of acid sulphite of sodium, whence anisoate of sodium crystallises on cooling. To the 
 purified crystals, enough sulphuric acid is added to decompose the salt, the whole eva- 
 
ANISOL, 305 
 
 porated to dryness, and the acid extracted from the residue by absolute alcohol. It 
 crystallises from its aqueous solution in small laminae, which have a strong acid reaction, 
 and are very soluble in water, alcohol, and ether; they melt at about 120 C., and are 
 not volatile without decomposition. 
 
 Anisoates are mostly readily soluble. The sodium-salt, C 10 H 17 Na0 6 , and the barium- 
 salt, form white crystalline nodules. The silver-salt forms soluble nodules, and speedily 
 blackens when moist. F. T. C. 
 
 Stadeler and Wachter (Ann. Ch. Pharm. cxvi. 169) regard this acid as identical 
 with thianisoic acid, C 10 H 14 SO 4 ,the product which they obtain by treating anise-cam- 
 phor with nitric acid of specific gravity 1'106, then distilling and agitating the distil- 
 late with acid sulphite of sodium and alcohol. The atomic weights of the two acids 
 are nearly equal (anisoic acid = 234 ; thianisoic acid = 230), so that the determina- 
 tions of carbon and metal in Limpricht and Bitter's analyses of the silver and barium- 
 salts will agree with the one formula, as well as with the other. Moreover in Limpricht 
 and Hitter's analyses of both these salts, the amount of hydrogen found was much too 
 low for the formula of anisoic acid (in the barium-salt 5'44 per cent., by calculation 
 5'65 ; in the silver-salt 4*0 per cent., calculation 4*98), and the absence of sulphur 
 was not established by direct experiment. (See THIANISOIC ACID.) 
 
 AITISOIW. See ANISE, OIL OF. 
 
 ASTZSOZ.. Phenate of methyl Dracol C 7 H 8 = C fi H 5 (CIF)0. (C ah ours, Ann. 
 Ch. Phys. [3] ii. 274 ; x. 353 ; xxvii. 439.) This compound is formed by the 
 action of caustic baryta on anisic acid, or on its isomer, salicylate of methyl: also 
 directly from phenic acid, by the substitution of methyl for 1 at. hydrogen. It may 
 be obtained in various ways. Anisic acid distilled with excess of caustic baryta or 
 lime, is decomposed, anisol passing over as a volatile oil : C 8 H 8 3 + Ba 2 = C 7 H 8 + 
 C0 3 Ba 2 . The same result follows when salicylate of methyl is dropped on finely 
 powdered baryta, and the mixture gently distilled. A third method is to heat phenate 
 of potassium with iodide of methyl in a sealed tube, to 100 120 C. C 6 H 5 KO + 
 CH 3 I = C fi H 5 (CH 3 )0. + KI. The product of either of these reactions is washed with 
 dilute potash and with water, and rectified over chloride of calcium. 
 
 Anisol is a colourless, very mobile liquid, with a pleasant aromatic smell. It is in- 
 soluble in water, very soluble in alcohol and ether, insoluble in potash. Its specific 
 gravity at 15 C. is 0'991 ; it boils at 152 C., and distils un decomposed. It is isomeric 
 with benzoic alcohol and taurylic acid. 
 
 It may be distilled over phosphoric anhydride without decomposition. It dissolves 
 entirely in strong sulphuric acid, and is not precipitated by water, a copulated acid 
 being formed. This acid, which Cahours calls sulphanisolic, and Gerhardt methyl- 
 sulphophenic acid, has the formula C 7 H 8 S0 4 . By saturating the acid liquid with 
 carbonate of barium, a crystalline barium-salt is obtained, which contains 1 at. barium. 
 If fuming sulphuric acid be employed, not in excess, the addition of water separates 
 crystalline flakes of a neutral body, which Cahours calls sulphanisolide. Its formula 
 is C 14 H H S0 4 ; it is to sulphanisolic acid as sulphate of ethyl is to ethyl-sulphuric acid. 
 This body is best obtained by passing the vapour of sulphuric anhydride into arti- 
 ficially cooled anisol, and adding water to the mixture ; sulphanisolide is then de- 
 posited in fine needles, which are recrystallised from alcohol, while sulphanisolic acid 
 remains in solution. It forms soft silvery prisms, insoluble in water, soluble in alcohol 
 and ether. It melts at a gentle heat, and sublimes undecomposed. Strong sulphuric 
 acid converts it into sulphanisolic acid. 
 
 SrssTiTUTioN-DEKivATivES OF ANISOL. Chlorine and bromine form with 
 anisol crystalline substitution-compounds. The chlorine-compounds have not been 
 examined ; there are two bromine-compounds, bromanisol, C 7 H 7 BrO, and dibromanisol, 
 C 7 H 6 Br 2 0. The latter is soluble ill boiling alcohol, whence it crystallises in brillant 
 scales. It melts at 54 C., and at a higher temperature sublimes entirely in small 
 shining tables. 
 
 Fuming nitric acid acts energetically on anisol, forming three distinct nitro-com- 
 pounds, Nitranisol, Dinitranisol, and Trinitr anisol, according to the proportions of the 
 reagents and the duration of the reaction. Nitranisol, C 7 H'(N0 2 )O, is prepared by 
 adding fuming nitric acid by small portions to anisol, the mixture being kept cool by 
 ice. A bluish-black oily liquid is thus obtained, which is washed with dilute potash, 
 and rectified over chloride of calcium. Anisol distils over first, and when the boiling 
 point remains constant at about 260 C., the receiver is changed. Nitranisol is a clear 
 amber-coloured liquid, heavier than and insoluble in water, with an aromatic smell, 
 something like that of bitter-almond oil. It boils between 262 and 264 C. It is 
 not attacked by aqueous potash, even on heating. When gently heated with strong 
 sulphuric acid, it dissolves, and separates out again on the addition of water. -When 
 heated with fuming nitric acid, it is successively converted into di- and tri-nitranisol. 
 
 VOL. I. X 
 
306 ANISYL. 
 
 Dinitranisol, C 7 H 6 (N0 2 )*0, is prepared by boiling anisol for a few minutes with 
 excess of fuming nitric acid : on adding water, a yellow liquid is separated, which 
 soon solidifies into a yellow mass, which is recrystallised from boiling alcohol. It is 
 also obtained by heating anisic acid to 90 100 C., for about half an hour, with two 
 or three times its weight of fuming nitric acid : chrysanisic acid forms at the same time, 
 and is removed by dilute potash. Dinitranisol crystallises in long pale yellow needles, 
 insoluble even in boiling water, soluble in alcohol and ether. It melts at about 86 C., 
 and sublimes undecomposed. Aqueous potash does not attack it, even on boiling, 
 unless the solution be very strong, and even then long boiling is required : when 
 boiled with alcoholic potash, it is speedily decomposed, dinitrophenate of .potassium 
 being formed. 
 
 Trinitranisol, C'H^NO 2 )^), is formed when anisol, anisic, or nitranisic acid is 
 heated with a mixture of equal parts of strong sulphuric and fuming nitric acid. 
 Anisic acid is generally employed for its preparation. The mixture, which at first is 
 clear and colourless, is gently heated till it begins to become turbid, carbonic anhy- 
 dride being copiously given off. The heat is then removed, when there gradually 
 collects on the surface an oil, which solidifies on cooling. A large quantity of water 
 is then added, and the solid product is washed with boiling water, and crystallised from 
 a mixture of equal parts of alcohol and ether. The reaction is complete if 15 pts. 
 of the mixed acids be employed for 1 pt. anisic acid. Trinitranisol crystallises in 
 yellowish, very brilliant tables, insoluble in water, soluble in hot alcohol or in ether. 
 It melts at 58 -60 C., and if carefully heated, sublimes. Warm sulphuric or nitric 
 acid dissolves without decomposing it. Aqueous ammonia or dilute potash, does not 
 attack it, even on boiling ; but moderately strong aqueous potash gives it an intense 
 brown-red colour, and completely decomposes it on boiling, forming a slightly soluble 
 potassium-salt of an acid, which is isomeric with, but, according to Cahours, distinct 
 from picric, or trinitrophenic acid, which he designates picranisic acid. 
 
 All the nitro-derivatives of anisol are readily attacked by alcoholic sulphide of am- 
 monium, sulphur being separated, and anisidine and its nitro-derivatives being formed. 
 
 F. T. C. 
 
 The name given by Brandes and Reimann to a brown product, 
 obtained by extracting anise-seed, after previous treatment with alcohol, water, and 
 hydrochloric acid, with aqueous potash, and precipitating the alkaline solution by acetic 
 acid. F. T. C. 
 
 AXfXSTTRXC ACXD* C 10 H n N0 2 . An acid analogous to hippuric acid, produced 
 by the action of chloride of anisyl on the silver-compound of glycocoll (C*H 4 AgN0 2 + 
 C 8 H 7 2 C1 = AgCl + C IO H n N0 2 ). Acids, with aid of heat, convert it into glycocoll 
 and anisic acid. (Cahours, Ann. Ch. Pharm. ciii. 90.) 
 
 C 8 H 7 2 . A hypothetical radicle, supposed to be contained in anisic 
 acid, hydride of anisyl, and other anisic compounds. It may be regarded as salicyl, 
 C 7 H S 2 , in which 1 at. hydrogen is replaced by methyl, C 8 H 7 2 = C 7 H 4 (CH 3 )0 2 : and, 
 in fact, anisic acid and salicylate of methyl are not only isomeric compounds, but are 
 both decomposed in the same manner by caustic baryta. Anisic acid is, therefore, 
 to salicylic acid, as acetic is to formic acid. If, as Piria's recent researches (Ann. 
 Ch. Pharm. xciii. 262) tend to show, salicylic acid be not monobasic but dibasic, the 
 clear analogy between it and anisic acid, would probably lead to the conclusion 
 that the latter acid is also dibasic ; in which case, all anisic compounds must be 
 regarded as containing a diatomic radicle, C 8 H 6 0, rather than a monatomic radicle, 
 C 8 H 7 2 . 
 
 BROMIDE OF ANISYL. C 8 H 7 2 .Br. (Cahours, Ann. Ch. Phys. [3] xiv. 486.) 
 Prepared by dropping dry bromine (excess of which must be avoided), upon hydride 
 of ^anisyl : heat is evolved, hydrobromic acid given off, and the mixture solidifies. The 
 solid product is rapidly washed with ether, pressed between filter-paper, and crystallised 
 from ether. It forms white, silky crystals, which are volatile without decomposition. 
 Strong boiling potash gradually converts it into anisate and bromide of potassium. 
 
 CHLORIDE OF ANISYI,. C 8 H 7 2 .C1. (Cahours, Ann. Ch. Phys. [3] xxiii. 351.) 
 When dry anisic acid is treated in a retort with pentachloride of phosphorus, a 
 violent action takes place, and a mixture of products passes into the receiver. These 
 are fractionally distilled, that part which boils between 250 and 270 C. being collected 
 apart, washed with a little water, and rectified over chloride of calcium. Chloride of 
 anisyl also seems to be formed by the action of chlorine on the hydride. It is a 
 colourless liquid, with a strong smell : its boiling point is 262 C.; its specific gravity it 
 1-261 at^l5. When exposed to moist air, it is speedily decomposed into hydrochloric 
 and anisic acids. In contact with dry ammonia, it evolves heat, and is converted into 
 amsamide (q. v.). Alcohol and wood-spirit attack it energetically, forming hydro- 
 chloric acid, and anisate of ethyl and methyl respectively. 
 
ANKERITE ANNOTTO. 307 
 
 HYDRIDE OF ANISYL, C 8 H 8 2 = C 8 H 7 2 . H. Anisylwasserstoff '; Anisylous 
 Acid; Anisic Aldehyde; Anisal. (Cahours. Ann. Ch. Phys. [3] xiv. 484 ; xxiii. 354.) 
 Formed, together with anisic acid, by the oxidation of oil of anise, or of anisic 
 alcohol ; in the latter case, the action of platinum-black is sufficient to produce the 
 effect. It is prepared by gently heating oil of anise for about an hour, with tliree 
 times its volume of nitric acid of specific gravity T106 (14 Baume): the heavy oil 
 which is thus formed is washed with dilute potash, and distilled. The distillate is 
 agitated with a warm solution of acid sulphite of sodium, of specific gravity 1/25 ; the 
 crystalline compound thus formed is collected on a funnel, thoroughly washed with 
 alcohol, dissolved in as little hot water as possible, and the solution heated with 
 excess of strong sodic carbonate, when the hydride of anisyl separates out and floats 
 on the surface. It is then purified by redistillation. The reaction is as follows, oxalic 
 acid being simultaneously formed : 
 
 + O 6 = C 8 H 8 2 + C 2 H 2 4 + H 2 
 
 Oil of anise. Hydride Oxalic 
 
 of anisyl. acid. 
 
 Hydride of anisyl is a yellowish liquid, with a burning taste, and an aromatic smell 
 somewhat like that of hay : its specific gravity at 20 C. is T09, and its boiling-point 
 253 255 C. It is almost insoluble in water, but soluble in all proportions in alcohol 
 and ether. Strong sulphuric acid dissolves it, forming a dark-red solution, whence it 
 is reprecipitated by water. When exposed to the air, it gradually absorbs oxygen, and 
 is converted into anisic acid ; the same change is produced more rapidly by means of 
 oxidising agents, such as platinum-black, or dilute nitric acid. Strong nitric acid 
 converts it into nitranisic acid. Strong aqueous potash does not dissolve it till after 
 long boiling ; fused or alcoholic potash convert it into anisate, with evolution of hydro- 
 gen, or formation of anisic alcohol. Prolonged contact with caustic ammonia converts 
 it into anishydramide (q. v.~). Pentachloride of phosphorus attacks it energetically, 
 the mixture thickening, and finally becoming a black pitchy mass, and a scanty distillate 
 is obtained, consisting of chloride of phosphoryl, together with a neutral oil having a 
 strong smell of turpentine. 
 
 Hydride of anisyl possesses the property peculiar to aldehydes, of forming crys- 
 talline compounds with acid sulphites of alkali-metal. Sulphite of anisyl-sodium, 
 C 8 H 7 Na0 2 ,SO- + aq. (Bertagnini, Ann. Ch. Pharm. Ixxxv. 268), is obtained by 
 agitating hydride of anisyl with a strong solution of acid sulphite of sodium : the mix- 
 ture assumes the consistence of butter, and finally becomes crystalline. When dried 
 and recrystallised from boiling alcohol, it forms colourless, shining scales ; but it is 
 always partially decomposed during crystallisation. It is soluble in cold water, and 
 is reprecipitated by acid sulphite of sodium, in which it is almost insoluble : its aque- 
 ous solution is decomposed by boiling, hydride of anisyl being formed and sulphurous 
 anhydride evolved. Acids and alkalis decompose it also. Ammonia dissolves it, form- 
 ing oily drops which gradually solidify into crystals of anishydramide. Iodine and 
 bromine decompose it readily. The potassium- and ammonium-compounds are similar 
 to the sodium-compound, both in mode of formation and in general properties. F.T. C. 
 
 -A.jM3ER,lTE. A variety of dolomite, C0 3 CaMg, in which the magnesium is 
 partly replaced by iron and manganese. According to Berthier (Pogg. Ann. xiv. 
 103), it fuses to a crystalline compound with carbonate of sodium. 
 
 AKTETxlBERCITE. See NiCKEL-GItEEN. 
 
 (Tempering, Recuit, Anlassen.*) Many bodies when raised to a 
 high temperature and quickly cooled, become very hard and brittle. This is a great 
 inconvenience in glass, and also in steel, when this metallic substance is required to 
 be soft and flexible. These inconveniences are avoided by cooling the substance very 
 gradually ; and the process is called annealing. Glass vessels, or other articles, are 
 carried into an oven or apartment near the great furnace, called the leer, where they 
 are permitted to cool, more or less quickly, according to their thickness and 
 bulk. The annealing or tempering of steel, or other metallic bodies, consists simply 
 in heating them, and suffering them to cool again, either upon the hearth of the 
 furnace, or in any other situation where the heat is moderate, or at least the tempera- 
 ture is not very low. U. (See Dictionary of Arts, Manufactures, and Mines, i. 162.) 
 
 ANNOTTO. The pellicles of the seeds of the Bixa orcllana, a liliaceous shrub, 
 from 15 to 20 feet high in good ground, afford the red masses brought into Europe 
 under the name of annotto, anatto, arnatto, arnotto, orlean, and roucou. 
 
 The annotto commonly met with in this country is moderately hard, of a brown 
 colour on the outside and a dull red within. It is difficultly acted upon by water, 
 and tinges the liquor of a pale brownish -yellow colour. In rectified spirit of wine, 
 it dissolves very readily, and communicates a high orange or yellowish-red colour. 
 
 x 2 
 
308 
 
 ANORTHITE ANOXOLUIN. 
 
 Hence it is used as an ingredient in varnishes, for giving more or less of an orange 
 cast to the simple yellows. 
 
 Ether is the best solvent of annotto. Potash and soda, either caustic or carbonated, 
 disolve annotto in large quantity, from which solutions it is thrown down by acids 
 in small flocks. The alkaline solutions are of a deep red colour. Chlorine de- 
 colorises the alcoholic solution of annotto, the liquid becoming speedily white and 
 milky. If strong sulphuric acid be poured on annotto in powder, the red colour passes 
 immediately to a very fine indigo blue : but this tint is not permanent, changing to 
 green, and finally to violet, in the course of twenty-four hours. This property of 
 becoming blue belongs also to saffron. Nitric acid, slightly heated on annotto, 
 sets it on fire, and a finely divided charcoal remains. Annotto is soluble both in 
 essential oils, as oil of turpentine, and in fixed oils. (Boussingault, Ann. Ch. Phys. 
 xxviii. 440.) 
 
 Annotto contains a crystalline yellow colouring matter, called bixin (q.v.~), which, 
 when treated with alkalis, in contact with air, absorbs oxygen, and is converted into a 
 red substance called bixein. Annotto is used in dyeing, but the colours produced by it 
 are all fugitive ; also for colouring cheese. U. (See Ure's Dictionary of Arts, Manu- 
 factures, and Mines, i. 178.) 
 
 ANODE. Faraday's term for the positive pole or electrode in the voltaic circuit. 
 (See ANION and ELECTBICITY.) 
 
 AiaORTHlTE. Ca 2 O.Si0 2 + Al 4 3 .Si0 2 = (Ca aP)Si0 4 . A mineral belonging to 
 the felspar family. It occurs in small crystals belonging to the triclinic system ; also 
 massive, with granular, columnar, or coarsely lamellar structure. Cleaves perfectly in 
 two directions, inclined to, one another at 85 48'. Specific gravity 2-66 278. 
 Hardness = 6 7. Transparent to translucent, with white, greyish or reddish colour, 
 and vitreous lustre. Streak uncoloured. Fracture conchoidal. Brittle. Before the 
 blowpipe it melts, and forms with soda a milk-white enamel. Strong hydrochloric 
 acid decomposes it completely, but does not gelatinise it. 
 
 Anorthite is found on Vesuvius and Somma, in the island of Procida, in Corsica, near 
 Bogoslowsk in the Ural, on Hecla and in other localities in Iceland, in Java, in the 
 island of St. Eustache in the Antilles, and in the meteorite of Juvenas. The follow- 
 are analyses : 
 
 SiO 2 
 Al'O 8 
 Fe 4 
 Ca 2 
 Mg 2 
 Na 2 
 K?0 
 
 Ni 2 and Co 2 
 Water 
 
 G. Rose. 
 
 Deville. 
 
 Damour. Waltersha usen. Potvka. 
 
 Somma. 
 
 Antilles. 
 
 Hecla. Hecla. 
 
 Ural. 
 
 . 44-49 . 
 
 . 45-8 . 
 
 . 45-97 . 45-14 . 
 
 . 46-79 
 
 . 34-46 . 
 
 . 35-0 . 
 
 . 33-28 . 
 
 32-11 . 
 
 . 33-16 
 
 . 074 . 
 
 
 
 . 1'12 . 
 
 2-03 . 
 
 . 3-04 
 
 . 15-68 . 
 
 '. 177 ! 
 
 . 17-21 . 
 
 18-32 . 
 
 . 15-97 
 
 . 5-26 . 
 
 . 0-9 . 
 
 . 
 
 
 
 
 
 . 
 
 . 0-8 . 
 
 . 1-85 . 
 
 1-06 . 
 
 . 1-28 
 
 
 
 
 
 
 
 0-22 . 
 
 . 0-55 
 
 . 
 
 . 
 
 
 
 0-77 . 
 
 
 
 . . 
 
 . . 
 
 . . 
 
 0-31 . 
 
 . 
 
 100-63 
 
 100-2 
 
 99-43 
 
 99-96 
 
 100-79 
 
 The formula above given, which is that of an orthosilicate, requires 43-2 SiO 2 , 36'8 
 A1 2 3 , 20-0 Ca 2 0. 
 
 The following are varieties of anorthite having nearly the same composition and 
 crystalline form: 1. Amphodclite has the structure and specific gravity of anorthite; 
 found at Logi, in Finland, and Tunaberg in Sweden. 2. Bytownite, from Bytown in 
 Canada. 3. Diploite or Latrobtte, from the island Amitok on the coast of Labrador. 
 Rose-red, with the form, structure, and density of anorthite. 4 Indianite, from 
 Hindostan. Granular masses, having the structure of felspar. 5. Lepol-itc, from Logi 
 and Orijarfvi in Finland. Resembles amphodelite. 6. Lindsayitc, from the same 
 localities, appears to be the same altered, and containing a^ few per cent. ofwiter. 
 7. Polyargitc, from Tunaberg. Rose-red ; granular ; gives 'off water when heated. 
 and becomes colourless. 8. Eoscllan, from Aker, Sodermanland. Exhibits similar 
 properties. 9. Sundvilkite, from Kimito, Finland. Has the form of felspar; and 
 specific gravity = 270. 10. Wilsomite, from Canada. Rose-red; specific gravity 
 276 277 : hardness very different in different parts ; becomes colourless when 
 heated ; gives off water and melts before the blowpipe, swelling up to a white enamel. 
 (Dana, ii. 234 ; Rammelsberg's Mineralchemie, 590.) 
 
 ANOTTO. See ANNOTTO. 
 
 According to Leconte and Go u mo ens (Compt. rend, xxxvi. 
 834), fibrin, muscular fibre, albumin, vitellin, globulin, and casein, contain two 
 different s\\bstances, one of which, called oxoluin, dissolves in glacial acetic acid, while 
 the other, anoxoluin, is insoluble in that acid. In fibrin and muscular fibre, the 
 
ANTHOKIRRIN ANTHRACOXENE. 309 
 
 anoxoluin may also be distinguished, when examined by the microscope, by its fibrous 
 structure, from the oxoluin, which is granular. Anoxoluin dissolves with reddish colour 
 in dilute sulphuric acid, whereas oxoluin dissolves but sparingly and with yellowish 
 colour. Anoxoluin is precipitated of a carmine-red colour by mercuroso-mercuric 
 nitrate : oxoluin, light rose-red. Chromic acid dissolves anoxoluin at 100 C., forming a 
 red-brown solution, whereas oxoluin is not affected by it. Hydrochloric acid dissolves 
 the former readily, forming a violet solution, the latter but sparingly, with yellowish 
 colour. A boiling saturated solution of tartaric acid dissolves anoxoluin readily, but 
 not oxoluin. 
 
 The yellow colouring matter of the flowers of yellow toad- 
 flax (Linaria vulgaris or Antirrhinum Linaria, L). It may be prepared by treating 
 the flowers with 'warm alcohol, evaporating to dryness, exhausting with water to dis- 
 solve sugar, gum, &c., treating the insoluble portion with alcohol, evaporating again 
 and digesting in ether. On evaporating the ethereal solution, the colouring matter is 
 obtained in yellow nodules. It melts when heated, and sublimes apparently without 
 decomposition. The fixed alkalis dissolve it with red colour ; ammonia and alkaline 
 carbonates, with dark yellow colour : from these solutions it is precipitated yellow by 
 acids. Minerals acids dissolve it with red colour, the solutions becoming yellow on 
 standing. The concentrated aqueous solution is precipitated reddish-yellow by acetate 
 of lead, greenish-yellow by cupric-salts, orange-yellow by protochloride of tin. With 
 hydrate of alumina it forms a pale yellow lake. The flowers of toad-flax are some- 
 times used for dyeing yellow ; stuffs dyed with them have a light yellow colour, but 
 assume a dirty yellow colour when exposed to the air. (Eiegel, Pharm. Centralb. 
 1842, 454.) 
 
 AUTSIOXITAK 1 or CYAOTXW. The blue colouring matter of flowers. (See 
 COLOURING MATTER.) 
 
 AHTTHOXiEUCXN. The white colouring matter of flowers. (See COLOURING 
 MATTER.) 
 
 ANTHOPHlTXiXiXTE. A mineral belonging to the amphibole family. (See 
 HORNBLENDE.) 
 
 ATtfTHOSIBSRZTE. A native silicate of iron, found at Antonio Pereira, in 
 Minas Greraes, Brazil. It has an ochre-yellow colour inclining to yellow-brown, 
 and a fibrous radiated structure. Its composition, according to Schnedermann's 
 analysis, is Si 9 Fe 8 24 + 2H 2 = 2Fe 4 3 .9Si0 2 + 2H 2 0. 
 
 AXTTHOXAIO'THXXX. The yellow colouring matter of flowers. (See COLOURING 
 MATTER. ) 
 
 ANTHRACENE or ACTTHRACHN*. Syn. with PARANAPHTHALIN. 
 
 ANTHRACITE. Blind coal, Kilkenny coal, or Glance coal. There are three 
 varieties. 1. Massive, the conchoi'dal of Jameson. Its colour is iron-black, some- 
 times tarnished on the surface, with a resplendent lustre. Fracture conchoi'dal, with 
 a pseudo-metallic lustre. It is brittle and light. It yields no flame, and leaves 
 whitish ashes. It is found in the newest floetz-formations, at Meissner, in Hesse, and 
 Walsall in Staffordshire. 2. Slaty anthracite. Colour black, or brownish-black. 
 Imperfectly slaty in one direction, with a slight metallic lustre. Brittle. Specific 
 gravity 1-4 to 1-8. Consumes without flame. It is composed of 72 carbon, 13 silica, 
 3-3 alumina, and 3*5 oxide of iron. It is found in both primitive and secondary- 
 rocks : at Calton Hill, Edinburgh ; near Walsall, Staffordshire ; in the southern parts 
 cf Brecknockshire, Carmarthenshire, and Pembrokeshire, whence it is called Welsh 
 culm ; near Cumnock and Kilmarnock, Ayrshire ; and mostly abundantly at Kilkenny, 
 Ireland. 3. Columnar anthracite. Small short prismatic concretions, of an iron- 
 black colour, with a tarnished metallic lustre. It is brittle, soft, and light. It yields 
 no flame or smoke. It forms a thick bed near Sanquhar in Dumfriesshire ; at Salt- 
 coats and New Cumnock in Ayrshire. It occurs also at Meissner in Hesse. TJ. (See 
 lire's Dictionary of Arts, Manufactures, and Mines.) 
 
 AN THRACOXiXTE or ASTTHS ACQUITS, A variety of calc-spar or limestone, 
 coloured black or blackish-brown, by coal and bituminous matter, occurring in certain 
 aluminous schists, and similar formations containing vegetable and animal remains, 
 as at Andreasberg in the Hartz, and at Christiania in Norway. When the bitumen pre- 
 dominates, the mineral is called stinkstone, from the property which it possesses of 
 emitting, when rubbed or cracked, an odour like that of putrefying animal remains. 
 
 ANTHRACOXENE. A fossil resin which occurs in layers of great extent, and 
 2 inches thick, between the strata of coal at Brandeisl, near Schlau in Bohemia. It 
 is brownish-black in the mass, but exhibits a hyacinth-red colour in thin layers ; has 
 
 x 3 
 
310 ANTHROPIN ANTICHLOR. 
 
 a shining surface, and conchoi'dal fracture ; is brittle, and yields a yellowish-brown 
 powder. It melts and swells up strong when heated, and burns with a not unpleasant, 
 odour, leaving a residue of ferric oxide, lime, sulphuric acid, and silica. It appears to 
 be a mixture of several substances. Ether dissolves a portion of it, leaving a resin, 
 which has, according to Laurent, the composition C^H^O 15 . The ethereal solution 
 deposits after partial evaporation, a brown powder, containing C SO H &1 7 , and this, 
 when exposed to the air, takes xip oxygan, and becomes partially soluble in alcohol ; 
 and the alcoholic solution, precipitated with acetate of copper, yields a flocculent pre- 
 cipitate, containing oxide of copper, in combination with a resin, whose composition is 
 expressed by the formula 6 Y80 // 56 13 . The portion left undissolved by the alcohol 
 appears to contain C^R^GP. (Handw. d. Chem. 2 te Aufl. ii. 39.) 
 
 .UNTHRAIUTXIXC ACID. See PHHKTLCABBAHIO Aero. 
 
 AWTHH-OPIW. Heintz, in examining human fat, obtained, besides stearic acid, 
 an acid which melted at 52 C., and gave by analysis numbers corresponding to the 
 formula C 17 H :i2 2 . This he at first supposed to be a peculiar acid (anthropic acid) 
 existing in the fat in the form of a glyceride (anthropin) ; but later investigations 
 proved that it was a mixture of stearic acid with margaric or palmitic acid. (Pogg. 
 Ann. Ixxxiv. 238 ; Ixxxvii. 233.) 
 
 AltiTTXARXXT, C 14 H 20 5 + 2H 2 0. The poisonous principle of the Upas antiar, a 
 kind of green resin which exudes from the upas tree (Antiaris toxicaria), and is em- 
 ployed by the Javanese for poisoning their arrows. It is extracted by exhausting 
 the upas with boiling alcohol, evaporating to dryness after the antiar-resin (see below) 
 has deposited, treating the extract with water, and evaporating to a syrup; the 
 antiarin then takes the form of scales, which are purified by recrystallisation. It is 
 without odour, dissolves at 22 0- 5 C. in 251 parts of water, 70 parts of alcohol, and 2'8 
 pts. of ether ; the solution is neutral to test-papers. It likewise dissolves in dilute acids. 
 When dried at ordinary temperatures, it contains 13*4 per cent of water of crystalli- 
 sation, which it goes off at 112 C. It melts at 220 C. into a colourless liquid, which 
 assumes a vitreous aspect on cooling, and at a higher temperatxire turns brown, and 
 exhales acid vapours. Dehydrated antiarin contains C 14 H 20 5 (62'69 p.c. C and 7 '45 
 H.) Sulphuric acid colours antiarin brown. Hydrochloric and nitric acids dissolve 
 it without alteration ; so likewise do potash and ammonia. 
 
 Antiarin applied to a wound produces vomiting, convulsions, diarrhoea, and soon 
 afterwards death ; its poisonous action is remarkably accelerated by mixture with a 
 soluble substance, such as sugar. (Mulder, Ann. Ch. Pharm. xxviii. 304.) 
 
 AXTTXAR REEXKT, C I6 H 24 0. The upas antiar also contains a resin which does 
 not exhibit any poisonous action. It is extracted by treating the upas with boiling 
 alcohol or ether, and is deposited on cooling in white, odourless, glutinous flakes, 
 having a density of 1*032 at 20 C., melting at 60 ; insoluble in water ; soluble in 325 
 pts. of alcohol at 20, and in 44 pts. of boiling alcohol. Boiling ether dissolves f pt. 
 of the resin. It dissolves readily in essential oils, and is sparingly dissolved by caustic 
 potash. Its alcholic solution is not precipitated by alcoholic acetate of lead ; but on 
 adding water to the mixture, a plastic mass is precipitated containing 23*44 per cent. 
 oxide of lead. (Pelletier and Caveutou, Ann. Ch. Phys. xxvi. 57; Mulder, 
 Ann. Ch. Pharm. xxvii. 307.) 
 
 AlffTXCHXiOR. The application of alkaline hypochlorites (chloride of lime, &c.) 
 to the bleaching of cotton and linen, is attended with this inconvenience, that the 
 fibre is apt to retain a quantity of free chlorine, which gradually rots and destroys it. 
 Hence the necessity of removing this free chlorine, either by long continued washing, 
 or by the application of some reagent which can unite with the chlorine, and convert 
 it into an innocuous compound. Such reagents are called " Antichlors : " their use is 
 especially necessary in the paper manufacture, in which long continued washing in- 
 volves a considerable waste of the pulp, and on the other hand, the non-removal of the 
 free chlorine is attended with a gradual rotting of the goods after stowage, fading of 
 the coloured quantities, and in some instances partial obliteration of documents 
 written upon the paper thus imperfectly prepared, besides injury of the delicate 
 machinery of the manufactory. 
 
 The first substances used for this purpose were the neutral and acid sulphites of 
 sodium (sulphite and bisulphite of soda). A patent for this application of the 
 acid sulphite was granted in 1847 to Mr. Henry Donkin, a manufacturer of paper- 
 maker's machinery, &c. at Bermondsey, and it was largely used till 1853, when it was 
 superseded by hyposulphite of sodium^ which is both cheaper to prepare and more 
 efficacious, its practical value being just double that of the acid sulphite. (See 
 HYPOSULPHITES, under SULPHUR.) The products formed by the action of chlorine, (or 
 hypochlorous acid) on sulphite or hyposulphite of sodium, are sulphate and chloride of 
 sodium, both of which are perfectly innocuous, and easily removed by washing. 
 
ANTICHLOR ANTIMON Y. 311 
 
 To ensure the complete removal of the free chlorine, the bleached paper or other 
 material, or the wash water which runs from it, must be tested with a mixture of 
 iodide of potassium and starch : the slightest trace of chlorine will be indicated by a 
 blue colour. To ascertain whether an excess of the antichlor has been used, add to the 
 mixture of starch and iodide of potassium a few drops of the bleaching liquid, so as 
 to produce a blue colour, and then add a portion of the liquid to be tested; if 
 the antichlor is present in excess, the colour will be destroyed. 
 
 Sulphide of calcium, prepared by boiling sulphur with milk of lime, has also been used 
 as an antichlor ; so likewise has a solution of protochloride of tin in hydrochloric acid ; 
 in the latter case, however, it is necessary, after the completion of the bleaching 
 process, to add carbonate of sodium, in order to neutralise the free hydrochloric acid, 
 which would otherwise act as injuriously as the free chlorine itself. The precipitate 
 of oxide of tin thereby produced is quite white and soft, and does not interfere with 
 the subsequent stages of the paper manufacture. 
 
 Lastly, coal-gas has been used since 1818, as an antichlor in paper making ; it does 
 not appear, however, to be so convenient as the reagents above-mentioned. (See 
 BLEACHING, Ure's Dictionary of Arts, Manufactures, and Mines.) 
 
 AlffTZCZXX.ORXSTZC THEORY. See CHLORINE. 
 
 AiWTZCS-OIIZTE. A hydrated silicate of magnesium belonging to the serpentine 
 group, found in the valley of Antigoria in Switzerland. (See SEBPENTINE.) 
 AK-TZ2VSOSTATES. See ANTIMONY, OXIDES OF. 
 
 AOTTXAXONXAXi COPPER. Native sulphide of copper and antimony, or Wolfs- 
 bergite. (See COPPEE, SULPHIDES OF.) 
 
 ANTIMOWZAIi COPPER GXiAHTCE. Also called Wolchite. A mineral 
 found in the iron mines at St. Grertraud, in Carinthia. Short rhombic prisms with 
 cleavage parallel to the brachydiagonal, imperfect; also massive. Specific gravity 
 5-7 5-8. Hardness = 3. Colour blackish lead-grey. Fracture conchoi'dal, to uneven ; 
 brittle. Contains, according to Schrotter's analysis, 28-60 S, 16'5 Sb, 6*04 As, 29'50 
 Pb, 17-35 Cu, 0-40 Fe, = 95-94. (Dana, ii. 82.) 
 
 AlBTTZllIONTAXi CROCUS. See ANTIMONY, OXYSULPHLDE OF. 
 AXTTXlKORTXAXi ZiEAB ORES. See LEAD, SULPHIDES OF. 
 
 ANTXIKOSTXAXi CTXCXEXi, and ABTTXltlON'XAXi SZXiVER. See ANTI- 
 
 MONY, ALLOYS OF. 
 
 ANTZItXONZAXi SUXiPHXDE of SXXiVER. See SILVER, SULPHIDE OF. 
 AXfTXMOOTZTE. Native Sulphide of Antimony. 
 See ANTIMONY, OXIDES OF. 
 
 Spiessglanzmetall, Spiessglassmetatt, Antimoine, Antimonium, 
 Stibium. Symbol, Sb. Atomic weight (as determined by the recent experiments of 
 Schneider) = 120-3.* 
 
 Some of the compounds of antimony were known to the ancients ; but the method of 
 preparing the metal itself was first described byBasilius Valentinus towards the end 
 of the fifteenth century. 
 
 Antimony is found native, and alloyed with other metals ; viz. with arsenic, nickel, 
 and silver ; also in combination with oxygen ; viz. as trioxide, in the form of antimony 
 bloom, white antimony, or Valentinite, Sb 2 3 and as tetroxide, antimony ochre, OP 
 Ccrvantite, Sb 2 4 ; in combination with sulphur, as stibnite or grey antimony ore, 
 Sb 2 S 3 ; with sulphur and oxygen, as red antimony, antimony blende, or Jcermesite 
 Sb 2 3 .2Sb 2 S 3 ; also as sulphide combined with various other metallic sulphides, chiefly 
 those of lead and silver, e.g. zinkenite, Pb 2 S . Sb 2 S 3 ; miargyrite, Ag 2 S.Sb 8 S 3 , &c. (See 
 SULPHANTLMONITES.) Lastly it occurs in ferruginous water, associated with arsenic, 
 tin, lead, and copper. 
 
 Preparation. All the antimony of commerce is obtained from the native tri- 
 sulphide, which occurs in many localities among the older rocks, gneiss, clayslate, 
 porphyry, &c. The sulphide is first separated from its gangue by fusion (p. 329), then 
 converted into oxide by roasting, and the oxide is subsequently reduced by coal or char- 
 coal; or the sulphide is at once reduced to the metallic state by fusion with a mixture 
 of charcoal and alkali, or with metallic iron. The following details are taken from 
 Gmelin's Handbook, vol. iv. p. 318. 
 
 1. Powdered grey sulphide of antimony, mixed with about half its weight of 
 charcoal powder to prevent caking, is roasted at a gentle heat (on the small scale, on a 
 
 * Berzelius estimated the atomic weight of antimonv at 129, wlpch number was for a long time 
 adopted; II. Rose (J. pr. Chem. Ixviii. 115,376) obtained the number J20'7; Dexter (I'ogj;. Ami. 
 c. 563) estimated it at 122-3. (See page 321.) 
 
 x 4 
 
312 ANTIMONY. 
 
 roasting dish; on the large scale, in a reverberatory furnace), with constant stirring, 
 the fire being gradually increased, but not sufficiently to fuse the mass. The sulphur 
 escapes in the form of sulphurous acid, and there remains a mixture of tetroxide 
 of antimony with a small quantity of trioxide, amounting to about of its weight 
 (G-eiger and Eeimann, Mag. Pharm. xvii. 136), and traces of undecomposed sulphide 
 of antimony: Antimony-ash, Calx Antimonii grisca per sc, or Cinis Antimonii. This 
 residue is then mixed with half its weight of cream of tartar, or with 1 part of char- 
 coal and i pt. potash, or with charcoal powder saturated with an aqueous solution of 
 carbonate of sodium, and fused in a covered crucible at a low red heat ; the fused mass 
 is then poured out into a hot mould partly filled with tallow, and the mould gently 
 tapped to make the metal sink to the bottom. The slag at the top consists of a mix- 
 ture of alkaline carbonate, double sulphide of antimony and potassium (or sodium) and 
 charcoal. The charcoal separates the oxygen from the antimony, and from a portion 
 of the alkali ; and the potassium or sodium thus eliminated separates the sulphur from 
 part of the sulphide of antimony still present, and then, in the form of sulphide, unites 
 with the remainder. 2. A mixture of 8 parts of sulphide of antimony, and 6 parts 
 of cream of tartar is heated in a crucible, nearly to redness, and from 2 to 3 parts of 
 nitre are added till the mass becomes perfectly fused. Or a mixture of 8 pts. of 
 sulphide of antimony, 6 pts. of cream of tartar, and 3 pts. of nitre, is projected by 
 small portions at a time into a red-hot crucible placed in a furnace, and the whole 
 is heated for a short time, till perfectly fused. The mass is then poured out as before. 
 The lower stratum consists of metallic antimony ; the upper, of double sulphide of 
 antimony and potassium mixed with charcoal. The charcoal in the black flux with- 
 draws oxygen from the potash; the potassium thus separated decomposes a portion of 
 the sulphide of antimony, setting the metal free ; and the resulting sulphide of 
 potassium unites with the still undecomposed sulphide of antimony. Probably accord- 
 ing to the following equation : 
 
 5Sb 2 S s + 6K 2 + 60 = 3(2K 2 S.Sb 2 S 3 ) + 4Sb + 6CO. 
 
 According to this, only f of the antimony contained in the sulphide should be obtained 
 in the metallic state, or from 100 parts of the sulphide of antimony, 29'15 parts of 
 regulus. This result accords with actual experience, 100 parts cf sulphide of anti- 
 mony being found to yield 27 parts of antimony. According to Liebig, however, by 
 leaving out the nitre in this process, 100 parts of sulphide of antimony produce 45 
 parts of the metal. 3. An intimate mixture of 8 parts of siilphide of antimony with 
 1 pt. of dry carbonate of sodium and 1 pt. of charcoal, heated in an earthen crucible, 
 and constantly stirred with a stick till it fuses quietly, and then poured out into the 
 casting mould, yields 57 parts (71 per cent.) of antimony, which is afterwards purified 
 from iron and copper by fusion with | its weight of nitre (Duf los, Br. Arch, xxxvi. 
 277 ; xxxviii. 158). In this process, rather more than 3 atoms of carbonate of sodium 
 and charcoal are used to 1 atom of trisulphide of antimony, so that a sufficient 
 quantity of sodium is set free to separate the whole of the sulphur : 
 Sb 2 S 3 + 3Na 2 + 30 = 2Sb + 3Na 2 S + 3CO. 
 
 The fusion must be continued for a long time, during which the mass is very apt to 
 boil over, and the antimony to burn away; the total amount obtained is only 66 per 
 cent., and the antimony still contains the whole of the other metals which were 
 present in the sulphide (Liebig, Mag, Pharm. xxxv. 120). 4. A mixture of 177 pts. 
 (1 at.) of sulphide of antimony with at most 82 pts. (3 at.) of iron filings or iron 
 nails is heated to bright redness in a closely covered crucible, and then left to cool : 
 Sb 2 S 3 + 6Fe = 2Sb + 3Fe 2 S. 
 
 The iron separates the whole of the sulphur, even at a gentle heat ; but a stronger 
 heat is required to fuse the sulphide of iron, and cause the antimony to form a distinct 
 stratum beneath it; at this high temperature, the antimony is apt to burn away if the 
 crucible be not well covered ; hence a layer of charcoal powder over the mixture is 
 useful. The addition of carbonate of potassium or sodium, or of nitre, accelerates the 
 fusion, because double sulphide of iron and potassium or sodium is thereby formed, 
 which is more readily fusible than pure sulphide of iron. For example, 22 pts. of 
 nitre are added to a strongly ignited mixture of 100 pts. of sulphide of antimony and 
 33 pts. of iron, or 6 pts. of nitre to 100 pts. of sulphide of antimony and 47 pts. of 
 iron ; or 100 pts. of sulphide of antimony, 43 pts. of iron, from 10 to 50 pts. of dry- 
 carbonate of sodium, and 2 to 5 pts. of charcoal are melted together. Berthier, how- 
 ever, found it most advantageous to fuse together 100 pts. of sulphide of antimony, 
 55 60 pts. of smithy scales, 45 pts. of carbonate of potassium, and 10 pts. of charcoal : 
 this mixture yielded 69 pts. of antimony; the mass, however, was found to froth up 
 considerably. Liebig (Mag. Pharm. xxxv. 120) gives the preference to this method ; 
 but the regulus which it separates from sulphide of antimony containing lead is 
 contaminated with that metal (Ann. Ch. Pharm. xxii. 62). A mixture- of 100 pts. of 
 
ANTIMONY. 313 
 
 -sulphide of antimony, 42 pts. of iron, 10 parts of dry sulphate of -sodium, and 2| pts. of 
 charcoal, yields between 60 and 64 pts. of antimony (Liebig). The slag obtained 
 in the second process likewise yields a large quantity of antimony by fusion with 
 iron, because the double sulphide of antimony and potassium is thereby converted into 
 double sulphide of iron and potassium. 
 
 Antimony obtained by the first, second, and third processes, the Eegulus Antimonii 
 simplex s. vulgaris, which solidifies in the mould, and has a stellated structure on the 
 upper surface, whence it has been called Regulus Antimonii stellatus, may contain 
 sulphur, potassium, arsenic, lead, iron, and copper; the antimony prepared by the 
 fourth method, Eegulus Antimonii martialis, may contain a large quantity of iron, 
 especially when the iron has been used in excess. The powdered antimony may be 
 freed from iron by fusing it with sulphide of antimony ; from sulphur, by fusion with 
 carbonate of potassium ; from sulphur and potassium, by fusion with nitre ; and, ac- 
 cording to Berzelius, from sulphur, potassium, arsenic, and iron, by fusion with from 
 to 1 pt. of antimonious oxide. 
 
 By fusing sulphide of antimony, or the slag obtained in the second process, with 
 tin, lead, copper, silver, &c., an antimony is obtained, which may contain small quan- 
 tities of these metals ; antimony thus prepared was formerly called Ecgulus Antimonii 
 jovialis, saturninus, venercus, lunaris, &c. 
 
 Purification. 1. By the following method, commercial antimony and likewise that 
 prepared on the small scale, may be perfectly freed from sulphur, arsenic, iron (when 
 not in too large quantity), and copper, but not from lead: hence the antimony sub- 
 jected to this process, should be free from lead. A mixture of 16 pts. of coarsely 
 pounded antimony with 1 pt. of grey sulphide of antimony and 2 pts. of dry carbonate 
 of sodium, is fused in a hessian crucible for an hour, care being taken to prevent any 
 charcoal from falling into the mass. When cold, the crucible is broken, and the slag 
 completely separated from the metal, which is again coarsely pulverised, fused with 
 1^ pt. dry carbonate of sodium for an hour, and, lastly, after cooling and removal of the 
 slag, once more fused with 1 pt. of carbonate of sodium. In this manner 15 pts. of pure 
 antimony are obtained (Liebig, Ann. Ch. Pharm. xix. 22). The sulphide of antimony 
 converts the other metals, except the lead, into metallic sulphides, which pass into the 
 slag in combination with sulphide of sodium. The remaining arsenic is separated by 
 the carbonate of sodium, in the form of arsenate of sodium. If any charcoal falls into 
 the crucible, it reduces arsenic from the arsenate of sodium, whereby the antimony is 
 again rendered impure (Liebig). Hence a black-lead crucible cannot be used; 
 such a crucible also reduces sodium, which then mixes with the antimony (Anthon, 
 Eepert. lix. 240). If the commercial antimony has been prepared with iron, and is 
 consequently richer in iron, a larger quantity of sulphide of antimony must be added 
 in the first fusion, that is to say, in proportion nearly corresponding to the iron (4 pts. of 
 sulphide of antimony and 4 pts. of carbonate of sodium, to 16 parts of the antimony) : 
 in this case, the loss of antimony is greater. As long as iron is present, it is impos- 
 sible to remove the arsenic by means of carbonate of sodium (Liebig, Ann. Ch. 
 Pharm. xxix. 58; Handworterb. 2 te Aufl. ii. 45; see also Buchner, Eepert. li. 267). 
 2. Well washed powder of algaroth is reduced with alkali and charcoal. By this 
 means, all impurities from the heavy metals are got rid of. Artus (J. pr. Chim. viii. 
 127) digests 1 pt. of finely powdered grey sulphide of antimony or glass of antimony, 
 with 2 pts. of common salt, 3 pts. of oil of vitriol and 2 pts. of water for eight hours, 
 then boils for one hour, and afterwards mixes the liquid with water till a permanent 
 precipitate begins to appear ; then filters ; precipitates the powder of algaroth by 
 adding more water; washes it thoroughly, and fuses 100 parts of the dry compound 
 with 80 parts of dry carbonate of sodium and 20 pts. of charcoal-powder for fifteen or 
 twenty minutes : 61 pts. of pure antimony are thus obtained. 3. A very pure metal 
 may be obtained by heating tartrate of antimony and potassium (tartar-emetic) to 
 bright redness, and digesting the resulting metallic mass in water, to remove any 
 potassium that may have been reduced at the same time. (Capitaine, J. Pharm. xxv. 
 516 ; also J. pr. Chem. xviii. 449.) 
 
 Purification from Arsenic only. The extensive use of antimonial preparations in 
 medicine, renders the removal of this impurity a point of particular importance. 
 1. Four pts. of powdered commercial antimony are mixed with five pts. of nitre and 
 2 pts. of dry carbonate of sodium (without the latter, insoluble arsenate of antimony 
 would be formed), and the mixture is projected into a red-hot crucible. The mass 
 remaining after the combustion (which takes place quietly) is then pressed together, 
 heated for ha if an hour to a higher temperature, so that it may become pasty but not 
 fused, and pressed down as often as it swells up from evolution of gas. After this, it 
 is taken out of the crucible with the spatula, while still hot and soft, then reduced to 
 powder, and boiled for some time in water, with frequent stirring. The water, to- 
 
314 ANTIMONY. 
 
 getlier with the finer powder, is then poured off; the coarser powder crushed with a 
 pestle, and boiled with a fresh quantity of water ; the two liquids with their deposits are 
 mixed ; and the insoluble portion is freed by repeated subsidence and decantation, and, 
 lastly, by washing on a filter, from the alkaline solution which contains the alkaline 
 arsenate and but a very small quantity of antimonate. The washed acid anti- 
 monate of potassium is white ; but if it contains lead, which cannot be removed by 
 nitric acid, it has a yellow colour. It is then fused with half its weight of cream of 
 tartar at a moderate red heat, and the resulting metallic antimony containing potassium 
 is pulverised and thrown into water, which removes the potassium and liberates pure 
 hydrogen gas ("Wohler, Pogg. Ann. xxvii. 628; also Ann. Ch. Pharm. v. 20.) Ac- 
 cording to C. Meyer (Ann. Ch. Pharm. Ixvi. 236; Centr. Blatt. 1348, 828) the use of 
 nitre is objectionable, because it gives rise to the formation of antimonate of potas- 
 sium, which destroys the exactness of the process. Meyer recommends a mixture of 
 nitrate and carbonate of sodium, whereby a mass is obtained which does not yield a 
 trace of antimony to water. This method is so exact that it may be used to separate 
 antimony from arsenic in quantitative analysis; moreover, the antimony thus ob- 
 tained is not contaminated with potassium or sodium. 2. One part of pulverised 
 antimony, prepared by the second method (p. 312), is rapidly fused with half its weight 
 of carbonate of potassium, and the mass is poured out ; the metal obtained is then 
 crushed, fused with one-fourth its weight of nitre, again poured out, the metal again 
 crushed, and fused with one-third its weight of hydrated antimonic acid ; and lastly, 
 the antimony, after being repulverised, is fused with one-third its weight of car- 
 bonate of potassium, and poured into the mould. This method completely removes 
 the arsenic (Th. Martius, Kastn. Arch. xxiv. 253). 3. If 32 pts. of antimony, 
 rich in arsenic, are fused with 4 pts. of nitre, the slag contains a large quantity of 
 arsenate of potassium ; and the resulting 30 pts. of metal fused with 3 pts. of nitre, still 
 yields a small quantity of arsenate of potassium and 27 pts. of metal; this, if again 
 fused with 2 pts. of nitre, yields a slag containing scarcely anything but antimonate of 
 potassium, and metallic antimony perfectly free from arsenic. If carbonate of potassium 
 be used instead of nitre, the separation of the arsenic is much more difficult (J. A. 
 Buchner, Eepert. xliv. 246). 4. One part of antimony prepared by the third 
 method, is heated with l pt. of oil of vitriol in a porcelain basin, stirring constantly 
 as long as sulphurous acid gas continues to be evolved, and water is carefully added 
 by small portions at a time, till a greyish-white intumescent mass is formed. This is 
 then mixed in a vessel made of antimony, with from 0'2 to 0-4 pt. finely powdered 
 fluor-spar, and 0'4 to 0'8 pt. oil of vitriol (according to the quantity of arsenic present). 
 The whole is then heated, with constant stirring, as long as hydrofluoric acid and 
 fluoride of arsenic are given off; the residue is afterwards gradually mixed with water, 
 and washed by decantation till the wash-water ceases to exhibit an acid reaction ; and 
 the remaining basic sulphate of antimony is reduced by fusion with half its weight of 
 cream of tartar, in a covered crucible. If a leaden vessel were used, antimony and 
 arsenic would be reduced together, and consequently the antimony obtained would not 
 be free from arsenic. (Duflos, Kastn. Arch. xix. 56; also, Schw. Ix. 353; further, 
 Schw. Ixii. 501; see also Buchner and Herberger, Eepert. xxxviii. 381, xliv. 
 246.) 
 
 Tests for Impurities in Antimony. 1. Sulphur. The powdered metal, when 
 heated with strong hydrochloric acid, gives off hydrosulphuric acid. 2. Potassium 
 or Sodium. The antimony appears more grey than white, and loses its lustre on 
 exposure to the air. Its powder has an alkaline taste, reddens moist tumeric paper, 
 and evolves hydrogen gas when put under water, giving up alkali to the liquid. 
 3. Arsenic. The metal, when fused in the air, emits a garlic colour. If its powder be 
 detonated with about \ pt. of nitre, and the resulting mass treated with water, a 
 filtrate is obtained, which contains arsenate and antimonate of potassium, so that 
 when supersaturated with hydrochloric acid, and rapidly saturated with hydrosul- 
 phuric acid gas, it first gives a yellowish red precipitate of pentasulphide of antimony, 
 and then, if rapidly filtered and preserved in a close vessel, gradually deposits a yellow 
 precipitate of peutasulphide of arsenic. The antimony ignited with an equal weight 
 of cream of tartar in a covered crucible, yields an alloy of potassium, arsenic, and 
 antimony, which, if reduced to powder under water, evolves arsenietted hydrogen, 
 recognisable by its depositing brown metallic arsenic on ignition (see ARSENIC). 4. Lead. 
 The powdered metal boiled with nitric acid nearly to dryness, and then treated with 
 water, yields a filtrate which contains nitrate of lead, and is consequently precipitated 
 by sulphuric acid. When the quantity of lead is large, a solution of antimony in 
 aqua-regia deposits crystalline needles of chloride of lead on cooling. If the antimony 
 contains sulphur besides the lead, the lead remains undissolved in the form of sulphate, 
 on treating the metal with nitric acid. If the antimonious oxide in the residue is then 
 dissolved out by warm hydrosulphate of ammonia, black sulphide of lead remains 
 
ANTIMONY. 315 
 
 behind, and if iron is present, black sulphide of iron also. 5. Iron. The finely 
 divided metal ignited with three times its weight of nitre, and washed with boiling 
 water, leaves a yellowish residue, from which boiling dilute hydrochloric acid sepa- 
 rates ferric oxide, which may be detected by ferrocyanide of potassium, &c. 
 6. Copper. When the lead has been precipitated from the nitric acid solution by 
 sulphuric acid, according to the method above given, the cupric oxide remains 
 dissolved, and may be recognised by its behaviour with hydrosulphuric acid, ferro- 
 cyanide of potassium, ammonia, or polished iron. A solution of antimony in aqua- 
 regia should give a yellowish-red precipitate with sulphide of ammonium, perfectly 
 soluble in excess of the precipitant. If a black residue is left, it must consist of 
 sulphide of lead, iron, or copper. (H. Kose.) 
 
 Properties. Antimony is a brilliant metal, having a bluish- white colour, and 
 highly lamellated structure. By melting it in a crucible, then leaving it to cool par- 
 tially, and pouring out the still liquid portion, it may be obtained in rhombohedral 
 crystals. Its tendency to crystallise is well shown in the cakes of metal which are 
 met with in commerce, the surface of which often exhibits beautiful stellate or fern- 
 like markings. Its density is from 6702 to 6*86. It is very brittle, and easily pul- 
 verised in a mortar. It melts at 450 C. (842 Fah.), and may be distilled at a white 
 heat in an atmosphere of hydrogen, but the distillation is very slow, in consequence of 
 the small density of the vapour. Metallic antimony occurs native in small quantity, 
 sometimes in rhombohedral crystals, at Andreasberg in the Harz, at Przibram in 
 Bohemia, at Sala in Sweden, and at Allemont in France. 
 
 Amorphous Antimony. Antimony is deposited from its solutions by electrolysis in 
 two different states. When thus precipitated, with a positive electrode of antimony, 
 from a solution of 5 pts. of tartar emetic and 5 pts. of tartaric acid dissolved in a 
 mixture of 2 pts. hydrochloric acid and 30 pts. water., it has a silvery-grey colour and 
 frosted surface, is hard in texture, has a radiating crystalline structure, and a density 
 of 6'55. But from a solution of 1 pt. of tartar emetic in 4 pts. of the ordinary chloride 
 of antimony (containing excess of hydrochloric acid ?) it is deposited with the colour 
 and appearance of polished steel, and a bright, metallic, amorphous fracture. Its 
 specific gravity is then only 5'78. This amorphous antimony, when heated or struck, 
 undergoes a rapid and intense molecular change throughout its mass, attended with 
 great evolution of heat (from 60 to upwards of 450 F.), increasing at the same time 
 in density, and approaching in colour and structure to the crystalline variety. At the 
 same time, a quantity of chloride of antimony and of gas, condensed within its pores 
 and retained with considerable force, is given off. No such change takes place in 
 the grey crystalline metal. By carefully triturating thin pieces of the amorphous 
 metal under water, it may be obtained in the state of a fine powder, exhibiting the 
 molecular property above mentioned. This change of antimony from the amorphous to 
 the crystalline state appears to be similar to that which has been observed in sulphur, 
 selenium, and other substances. (G. Gore, Proc. Roy. Soc. ix. 70.) 
 
 In a subsequent paper (Proc. Roy. Soc. ix. 304), Mr. Gore states that the evolu- 
 tion of heat accompanying the change " is not limited to a particular temperature, 
 but commences between 170 and 190 F., and increases in rapidity to some point 
 above 212 F., when it becomes sudden. The heat may be discharged either sud- 
 denly or gradually, according to the amount to be discharged relative to the cooling 
 influences present. The specific heat of the unchanged (amorphous) metal was found 
 to be 0*06312; and of the same specimens, after being gradually discharged, the 
 specific heat was not sensibly different. But the specific heat of the substance, after 
 sudden discharge, was found to be 0-0543. The total amount of heat evolved by the 
 substance during the change was sufficient to raise the temperature of its own weight 
 of ordinary antimony (specific heat = 0*0508) about 650 F." An acid solution of 
 fluoride of antimony yielded by electro-deposition, crystalline antimony not possessing 
 the heating powers. 
 
 Antimony is not sensibly altered by exposure to the air at common temperatures, 
 but oxidises quickly when melted. At a red heat, it takes fire, burning with a white 
 flame, and producing white fumes of the trioxide. A lump of the pure metal heated 
 on charcoal before the blowpipe, burns brilliantly, emitting copious white inodorous 
 vapours, and if left to cool before it is completely burnt away, becomes covered with 
 a white network of the crystallised oxide. If, on the contrary, the antimony is con- 
 taminated with arsenic and iron, it exhales a garlic odour, especially at the com- 
 mencement ; becomes covered with a slag of oxide of iron ; has a dull surface ; 
 ceases to burn as soon as the blowpipe flame is withdrawn ; and yields a yellow oxide. 
 (Liebig.) 
 
 Antimony is strongly attacked and oxidised by nitric acid, but not dissolved. The 
 degree of oxidation varies with the strength of the acid. If the acid be moderately 
 
316 ANTIMONY: ALLOYS. 
 
 dilute, the product consists of trioxide of antimony, mixed with a small quantity of 
 pentoxide ; with strong nitric acid, on the contrary, the product consists chiefly or 
 wholly of pentoxide (H. Kose, Analyt. Chem. i. 258). The metal is not acted 
 upon by dilute sulphuric acid, but when heated with the strong acid, it is converted 
 into sulphate, with evolution of sulphurous anhydride. In the state of fine powder, it is 
 dissolved by boiling hydrochloric acid, with evolution of hydrogen, but in the compact 
 State, it resists the action of that acid, even at the boiling heat. 
 
 Antimony forms, with acid or chlorous radicles, two classes of compounds, viz. 
 
 1. Antimonious compounds or tri-compounds of antimony, containing 1 atom of the 
 metal with 3 atoms of a monobasic acid-radicle, Cl, I3r, &c. or 2 atoms of metal with 
 3 atoms of a dibasic acid radicle, 0, S, &c., e. g. : 
 
 Trichloride of antimony ..... SbCP 
 Trioxide or antimonious oxide .... Sb 2 3 
 Trisulphide ....... Sb 2 S 3 
 
 2. Antimonic compounds or penta-compounds of antimony, in which 1 or 2 atoms of 
 metal are associated with 5 atoms of an acid-radicle, e. g. : 
 
 Pentachloride of antimony ..... SbCP 
 Pentoxide or antimonic oxide .... Sb 2 5 
 Pentasulphide ....... Sb' 2 S* 
 
 In the antimonious compounds, Sb = H 3 ; in the antimonic compounds, Sb = H 5 . 
 
 There are likewise a few compounds of antimony not included in either of these 
 series ; e.g. the tetroxide, SbO 2 , which may, however, be regarded as a compound of the 
 two oxides above mentioned, viz. antimonoso-antimonic oxide, Sb 2 3 .Sb 2 5 = 4Sb0 2 . 
 
 AXiiLO YS OP. Antimony unites with most of the heavy metals, 
 rendering them harder and more brittle. Most of the alloys are easily formed by 
 fusing the two metals together ; some occur native. The alkali -metals likewise form 
 alloys with antimony. 
 
 For the compounds of arsenic and antimony see ARSENIC. 
 
 Antimonide of Copper. Prepared by fusing the two metals together in equal quan- 
 tities is pale violet, very brittle, and of laminar texture. According to Karsten, 
 copper alloyed with 0'15 per cent, of antimony, becomes somewhat cold-short and 
 very hot-short. 
 
 Antimonide of Gold. The two metals unite very easily, melted gold even absorb- 
 ing vapour of antimony. An alloy of 9 pts. gold to 1 pt. antimony is very brittle, 
 white, and exhibits the fracture of porcelain. Gold loses its malleability by admixture 
 with about ^ of antimony. The antimony is easily expelled from the alloy by 
 heat. 
 
 Antimonide of Iron. A mixture of 7 pts. of antimony, and 3 pts. of iron heated to 
 whiteness in a crucible lined with charcoal, forms a white, very hard, slightly magnetic 
 alloy, which gives sparks when filed. An alloy of antimony and iron is always formed 
 when sulphide of antimony is reduced by iron in excess (regulus antimonii martialis}. 
 A very small quantity of antimony (0*23 per cent.) makes refined iron both hot- and 
 cold-short. 
 
 Antimonide of Lead. The two metals unite readily in all proportions. Lead is 
 hardened by admixture with antimony. An alloy of equal parts of the two is brittle 
 and ringing; 12 pts. lead and 1 pt. antimony form a malleable alloy, somewhat 
 harder than lead. Type-metal is an alloy of antimony and lead, usually containing 
 17 to 20 per cent, ot antimony. Sometimes other metals are added, e. g. 1 pt. bismuth 
 to 1C pts. lead and 2 pts. tin, or, for stereotype plates, JL to ^ of tin. The specific 
 gravity of alloys of lead and antimony is always above the mean. 
 
 Antimonide of Nickel, NiSb, occurs as a metallurgic product obtained by sublimation 
 in long hexagonal prisms, Another alloy, Ni 2 Sb, occurs as a natural mineral called 
 antimonial nickel or Breithauptite, in thin hexagonal plates of specific gravity 7'541, 
 hardness 5-5 ; fracture uneven; the recent fracture exhibits a light copper colour with 
 a tinge of violet ; powder red-brown. Not magnetic. Ignited in a glass tube, it yields 
 a small sublimate of antimony. On charcoal it forms an antimonial deposit, and can- 
 not be fused excepting in small pieces. It is but little attacked by simple acids, but 
 dissolves easily in aqua-regia. Analysis byStromeyer (Pogg. Ann. xxxi. 134) : 
 
 Sb . . Ni . . Fe . . Pb 8 S 
 63-73 . . 28-95 . 0-87 . . 6-44 = 99-99 
 59-71 . . 27-05 . 0-84 . . 12-36 = 99'96 
 
ANTIMONY: CHLORIDES. 317 
 
 It was formerly found in the Andreasberg mountains, with calc-spar, galena, and 
 smaltine ; but the vein has long been exhausted. A similar alloy may be obtained 
 artificially by melting 2 at. Ni with 1 at. Sb. (Dana, ii. 53.) 
 
 Antimonide of Tin, The alloy is easily formed by fusing the two metals together, 
 also by reducing sulphide of antimony with tin (regulus antimonii jovialis). Britannia 
 metal is an alloy of 9 pts. tin and 1 pt. antimony, frequently also containing small 
 quantities of other metals, as copper, zinc, and bismuth. Alloys of antimony with 
 tin, or tin and lead, sometimes also containing copper, are now much used for machinery 
 bearings in place of gun-metal. (See Ure's Dictionary of Arts, Manufactures, and 
 Mines, i 169.) 
 
 Antimonide of Zinc. Antimony forms with zinc, alloys of definite crystalline 
 character. A fused mixture of the two metals, containing from 43 to 70 per cent, of 
 zinc, deposits by partial cooling, silver-white rhombic prisms, containing from 43 to 
 64 per cent, of zinc. The alloy containing exactly 43 per cent, of zinc, appears to be 
 a definite compound, stibiotrizincyl, SbZn 3 . Mixtures containing from 33 to 20 per 
 cent, of zinc deposit rhombic crystals containing from 35 to 21 per cent, of zinc. The 
 alloy containing exactly 33 per cent, is stibiodizincyl, SbZn 2 . These alloys, especially 
 SbZn 3 , decompose water, with evolution of hydrogen at the boiling heat, and very 
 rapidly under the influence of acids. (J. P. Cooke, SilL Am. J. [2] xviii. 229; xx. 
 222.) 
 
 Antimonide of Potassium. Alloys of antimony and potassium may be obtained by 
 fusing the two metals together, or by igniting metallic antimony, or its oxide or 
 sulphide, with an organic salt of potassium. Thus, when 5 pts. of crude tartar and 
 4 pts. of antimony are slowly heated in a covered crucible till the mixture becomes 
 charred, then heated to whiteness for an hour, and left to cool, a crystalline regulus is 
 obtained containing 12 per cent, of potassium. This alloy decomposes water rapidly, 
 and oxidises slowly in the air when in the compact state, but becomes heated and takes 
 fire when rubbed to powder. (Lowig and S c h w e i z e r . ) 
 
 Antimonide of Silver. Ag 4 Sb and Ag 6 Sb occurs native as antimonial silver or 
 discrasite, in the form of six-sided prisms with truncated lateral edges ; also in scaleno- 
 hedrons, similar to those of calc-spar. Specific gravity 9*4 to 9*8; hardness 3 '5 to 4 ; 
 silver- white ; fracture uneven. Before the blowpipe, it gives off fumes of antimony, 
 and leaves a grey, non-malleable, metallic globule ; by continuing the heat on charcoal, 
 silver is obtained. It dissolves in nitric acid, leaving oxide of antimony. Analysis by 
 Klaproth: 
 
 Ag 4 Sb Ag fi Sb 
 
 .a. b. c. 
 
 Antimony . .24 24 16 
 
 Silver . 76_ 76 84 
 
 100 100 100 
 
 a is a coarse-grained variety from Wolfach, in Baden ; b lamino-granular, from 
 Andreasberg, in the Hartz ; c fine-grained, from "Wolfach. The mineral occurs also 
 at Wittichen, in Suabia ; at AHemont, in Dauphine ; at Casalla, in Spain ; and near 
 Coquimbo, South America. (Grm. vi. 199; Dana, ii. 35.) 
 
 Antimonide of Sodium resembles antimonide of potassium, and is prepared in like 
 manner. 
 
 Native trioxide of antimony. 
 
 , BROMIDE OF. SbBr 3 . This is the only known compound of 
 antimony and bromine, and is formed by direct combination. Antimony takes fire in 
 bromine vapour, or in contact with liquid bromine, running about on the surface in 
 melted globules. To prepare the compound, bromine is put into a retort, and dry 
 antimony powder is introduced through the tubulus, agitating each time till the 
 combination is complete. The product is then purified by distillation. It forms on 
 cooling a mass of colourless needles, deliquescent, melting at 90C., volatile at 270. 
 Water decomposes it, forming an oxibromide. 
 
 AWTIIVIOWY, CHLORIDES OF. Antimony and chlorine unite directly when 
 brought in contact, and if the antimony is in a state of fine division, the combination 
 is attended with visible combustion. The compound formed is a trichloride or a 
 pentachloride, according as the antimony or the chlorine is in excess. 
 
 TBICHLOBIDEOPANTIMONY, SbCl 8 , is obtained:!. Bypassing chlorine gas 
 slowly through a tube containing excess of antimony, or over heated trisulphide of 
 antimony, the chloride of sulphur formed at the same time being afterwards volatilised 
 
318 ANTIMONY : DETECTION. 
 
 by a gentle heat. - 2. By distilling 3 pts. of antimony with 8 pts. of mercuric chloride, 
 or 2 pts. of the trisulphide of antimony with 4-6 pts. of mercuric chloride : 
 
 Sb + 3HgCl = SbCP + 3Hg; and Sb'S 3 + GHgCl = 2SbCP + 3Hg*S. 
 3. By heating the trisulphide with strong hydrochloric acid, or metallic antimony with 
 hydrochloric acid to which nitric acid is added in successive small portions : if too 
 much nitric acid were added, a precipitate of oxide of antimony or antimonic acid 
 would be formed. A solution of the trichloride in excess of hydrochloric acid is thus 
 formed, and on subsequently distilling this liquid, water and hydrochloric acid pass 
 over first,, and afterwards the pure trichloride. 
 
 Trichloride of antimony is at ordinary temperatures a translucent fatty mass 
 thence called butter of antimony. It melts at 72 C., and boils at about 200 : fumes 
 slightly in the air, and is very corrosive. When thrown into water, it is decomposed 
 into hydrochloric acid and trioxide of antimony, which however remains united with 
 a portion of the chloride, forming a white powder called powder of algaroth. The 
 same decomposition takes place on adding water to the solution of the trichloride in 
 strong hydrochloric acid. The precipitate is redissolved by excess of hydrochloric 
 acid, and the solution, which contains hydrated trichloride of antimony, is the most 
 convenient that can be used for exhibiting the reactions of antimony. The addition 
 of tartaric acid to this solution, prevents its decomposition by water. 
 
 The anhydrous trichloride combines with ammonia, forming the compound NH 3 .SbCP, 
 and forms crystalline compounds with the chlorides of the alkali-metals. 
 
 PENTACHLORIDE OF ANTIMONY, SbCP, is formed, with brilliant combustion, 
 when finely powdered antimony is thrown into chlorine gas. It may be prepared by 
 passing dry chlorine over pulverised antimony, gently heated in a tubulated retort 
 provided with a receiver, or over the trichloride. Hofmann (Chem. Soc. Qu. J. xiii. 
 65) introduces metallic antimony coarsely powdered into a combustion-tube five or 
 six feet long, rising at an angle of 10 or 15, one end being fitted into a tubulature 
 of a two-necked glass globe, the other neck of which is connected with a tube supply- 
 ing dry chlorine. Combination takes place in the tube, and the products flow back- 
 wards into the globe, whilst the long layer of antimony prevents the escape of any 
 chlorine. Pentachloride of antimony is a colourless or yellowish, very volatile liquid, 
 which emits suffocating vapours. Water first converts it into a crystalline hydrate 
 and then decomposes it, forming hydrochloric and antimonic acids. It absorbs am- 
 monia and phosphoretted hydrogen, forming solid red-brown compounds. It absorbs 
 defiant gas, C 2 H 4 , as readily as chlorine, and forms Dutch liquid. By passing dry 
 olefiant gas and dry chlorine simultaneously through boiling pentachloride of anti- 
 mony, in a retort connected with an inverted condenser, large quantities of Dutch 
 liquid may be easily obtained. The pentachloride here acts as a carrier of free 
 chlorine, a purpose for which it may often be advantageously used (Hofmann, 
 loc. cit.) It likewise absorbs hydrosulphuric acid gas, at ordinary temperatures, forming 
 a white crystalline chlorosulphide of antimony, SbCPS, analogous to chlorosulphide of 
 phosphorus, POPS. With bisulphide of carbon, the latter being in excess, it yields 
 tetrachloride of carbon, trichloride of antimony, and free siilphur : 
 
 CS 2 + 2SbCl 5 = CC1 4 + 2SbCP + S 2 . 
 
 The mixture becomes very hot, and on cooling deposits crystals of trichloride of anti- 
 mony, mixed with sulphur-crystals, the tetrachloride of carbon remaining in the 
 liquid state (Hofmann, loc. cit.}. The pentachloride combines with hydrocyanic acid, 
 forming a white, crystalline, volatile compound, containing SbCP.SHCy ; also with 
 chloride of cyanogen. A white pulverulent substance containing 2SbCP.3SCl 2 , is ob- 
 tained by heating pentasulphide of antimony in dry chlorine gas ; it is decomposed at 
 300 C. into chloride of sulphur, trichloride of antimony, and free chlorine. 
 AJTTIftXOire, DETECTION 1 AND ESTIMATION 1 OF : 
 1. Blowpipe Reactions. Solid compounds of antimony fused upon charcoal, with 
 dry carbonate of sodium or cyanide of potassium, yield a brittle globule of antimony, 
 a thick white fume being at the same time given off, and the charcoal covered to some 
 distance around with a white deposit of oxide. ' If the heat be continued for some 
 time, the globule will be completely dissipated. The reduction with cyanide of potas- 
 sium may be performed in a porcelain crucible without charcoal. 
 
 The antimony globule is converted by nitric acid into a white oxide, soluble in a 
 boiling solution of cream of tartar. It is insoluble in pure hydrochloric acid, but dis- 
 solves easily on addition of a small quantity of nitric acid, forming a solution of the 
 trichloride, which is decomposed by water, forming a white precipitate, soluble in 
 excess of hydrochloric or tartaric acid. If tartaric acid be previously added, water 
 produces no precipitate. 
 
ANTIMONY: DETECTION. 319 
 
 2. Liquid Eeactions. The acid solution of the trichloride gives with hydrosul- 
 phuric acid gas, a brick-red precipitate of the trisulphide, easily soluble in sulphide of 
 ammonium, and reprecipitated by acids. With potash, it forms a white precipitate of 
 the trioxide, soluble in a large excess of the reagent. Ammonia forms the same pre- 
 cipitate, insoluble in excess. Carbonate of potassium or sodium also gives a white 
 precipitate of the trioxide, which dissolves in excess, especially of the potassium-salt, 
 but reappears after a while. If, however, the solution contains tartaric acid, the pre- 
 cipitate formed by potash dissolves easily in excess of the alkali, ammonia forms but 
 a slight precipitate, and only after long standing, and the precipitates formed by the 
 alkaline carbonates are insoluble in excess of those reagents. These last mentioned 
 characters are also exhibited by a solution of tartar-emetic (tartrate of antimony and 
 potassium). The solution of this salt is decomposed by the stronger acids, yielding a 
 white precipitate, consisting of acid tartrate of potassium, mixed with the oxide or a 
 basic salt of antimony. With solutions of barium, strontium, calcium, lead, and silver, 
 it forms white precipitates, consisting of tartar-emetic, the potassium of which is re- 
 placed by the other metal. 
 
 A solution of trichloride of gold, added to a solution of trichloride of antimony, or 
 other antimonious salt, forms a yellow precipitate of metallic gold, antimonic acid being 
 at the same time precipitated in the form of a white powder, unless the solution 
 contains a larger excess of hydrochloric acid : 
 
 4AuCl 3 + 3Sb 2 3 + 6H 2 = 4Au + 12C1H + 3Sb 2 5 . 
 
 The reduction is slow at ordinary temperatures, but is accelerated by heating. In a 
 solution of the trioxide (antimonious acid), in potash, trichloride of gold produces a 
 black precipitate, which affords a very delicate reaction for antimonious acid. Nitrate 
 of silver produces in a solution of trichloride of antimony, a white precipitate, from 
 which ammonia dissolves out chloride of silver, leaving oxide of antimony undis- 
 solved. In a solution of antimonious acid in potash, nitrate of silver produces a deep 
 black precipitate, insoluble in ammonia. In a solution of tartar-emetic, nitrate of 
 silver forms a white precipitate, perfectly soluble in ammonia : but if the solution be 
 previously mixed with excess of potash, nitrate of silver produces a black precipitate 
 insoluble in ammonia. 
 
 Zinc and iron precipitate antimony from its solutions, in the form of a black powder. 
 Copper precipitates it in the form of a brilliant metallic film, which may be dissolved 
 off by a solution of permanganate of potassium, yielding a solution which will give the 
 characteristic red precipitate with hydrosulphuric acid. (Odling, Guy's Hospital 
 Reports [3] ii. 249.) 
 
 Antimonic Addis distinguished from antimonious acid by the different colour of 
 the precipitate which it forms with hydrosulphuric acid (p. 328) ; but better by its 
 behaviour with chloride of gold and nitrate of silver. Trichloride of gold produces no 
 precipitate in solutions of antimonic acid, not even when they contain excess of potash. 
 Nitrate of silver, added to a solution of antimonate of potassium, forms a white preci- 
 pitate of antimonate of silver, perfectly soluble in ammonia : if the solution contains 
 excess of potash, the precipitate is brown from admixed oxide of silver, but even then 
 it is completely soluble in ammonia. The slightest trace of antimonious acid present 
 produces a black precipitate, insoluble in ammonia. If a small quantity of an oxide 
 cf antimony in the solid state be rubbed up with water to a milky liquid in a porcelain 
 capsule, then dried, and moistened with ammonio-nitrate of silver, a black spot will 
 be produced, if trioxide antimony is present, either in the free state or combined with 
 antimonic acid : but if only antimonic acid is present, no blackening will take place. 
 This is a very delicate reaction (Bun sen, Ann. Ch. Pharm. cvi. 1). Antimonic acid 
 may also be distinguished from the trioxide by its behaviour with hydriodic acid, 
 The pure trioxide dissolves in hydrochloric acid to which iodide of potassium is added, 
 producing a pale yellow liquid, containing tri-iodide of antimony, without separation 
 of iodine ; but antimonic acid or antimonate of antimony, forms under the same cir- 
 cumstances a solution coloured dark brown by free iodine : 
 
 Sb 2 3 + 6HI = 2SbI 3 + 3H 2 
 and Sb-0 5 + 10HI = 2SbF + 5H 2 -!- 41. 
 
 If the quantity of antimonic acid is considerable, the liquid gives off violet vapours on 
 boiling ; but even if it does not exceed a few hundredth^ of a milligramme, the free 
 iodine in the solution may be detected by shaking it up with a few drops of bisulphide 
 of carbon, which then exhibits a violet or amethyst colour when it rises to the surface. 
 It is of course essential that the hydrochloric acid do not contain free chlorine, and 
 that the iodide of potassium be free from iodate. (Bunjen.) 
 
320 ANTIMONY: ESTIMATION. 
 
 When the presence of antimony is suspected in liquids containing considerable 
 quantities of organic matter, as in cases of supposed poisoning by tartar-emetic or 
 other antimonial preparations, it is best to destroy the organic matter by oxidation 
 with hypochlorous acid. If the matter to be examined is solid, it should be cut into 
 small pieces ; if a large quantity of liquid is present, it must be brought by evaporation 
 to a convenient bulk. It is then mixed with strong hydrochloric acid, a gentle heat 
 applied, and chlorate of potassium added by small portions, till the liquid acquires a 
 light yellow colour. It is then heated till the odour of chlorine is no longer percep- 
 tible, and afterwards left to cool and filtered. From the clear liquid thus obtained, 
 the antimony may be precipitated by hydrosulphuric acid, or by metallic copper, and 
 the precipitates treated in the manner already described ; or the liquid may be intro- 
 duced into a Marsh's apparatus (see ARSENIC), with zinc and dilute sulphuric acid, 
 and the antimony reduced, either in the escape-tube by the heat of a lamp, or on a 
 porcelain plate held in the flame. The metallic deposit thus obtained may be dissolved 
 in aqua-regia, and the solution treated with hydrosulphuric acid, which will pro- 
 duce the characteristic brick-red precipitate. Another method of testing the deposit 
 is to moisten it with nitric acid, of specific gravity 1-42, then heat the vessel over a 
 lamp, and blow over the surface so as to cause the acid to evaporate without boiling. 
 The white deposit then remaining consists chiefly or wholly of trioxide of antimony, 
 which will produce a deep black spot with ammonio-nitrate of silver. A deposit of 
 metallic arsenic, treated in the same way, gives with ammonio-nitrate of silver, either 
 a yellow precipitate of arsenite, or a red-brown precipitate of arsenate of silver, accord- 
 ing to the degree of oxidation produced by the nitric acid. (Bun s en.) 
 
 3. Quantitative Estimation. 1. Antimony may be accurately estimated in the 
 form of tetroxide or antimonate of antimony, SbO 2 , that oxide being neither volatile 
 nor decomposible at a red heat. The antimony being precipitated from solution by 
 hydrosulphuric acid, the precipitate is washed and dried, then placed, together with 
 the filter, in a porcelain basin covered with a funnel, and fuming nitric acid poured 
 upon it. A violent action then takes place, the antimony and the greater part of the 
 sulphur being immediately oxidised : the oxidation of the sulphur may be com- 
 pleted by heating the vessel over a water-bath. The resulting white mass, consisting 
 of antimonic acid mixed with sulphuric acid, is converted by ignition into pure anti- 
 monate of antimony, containing 79'22 per cent, of the metal. The oxidation of the 
 sulphide of antimony cannot be conveniently effected by nitric acid of ordinary strength 
 (specific gravity 142), because that liquid boils at a temperature 10 C. above the melting 
 point of sulphur, and consequently the sulphur separated at the commencement of the 
 action collects in melted globules, which are extremely difficult to oxidise, and if left 
 in the mass during the subsequent ignition, would reconvert a portion of the oxide of 
 antimony into sulphide. Fuming nitric acid, on the contrary, boils below the melting . 
 point of sulphur, and the sulphur separated by its action takes the form of a fine 
 powder, which is easily oxidised at a gentle heat. If the sulphide of antimony is 
 mixed with a large quantity of free sulphur (which is often the case when it has been 
 dissolved in an alkaline sulphide and reprecipitated by an acid), it is best to remove 
 the free sulphur by washing the precipitate with bisulphide of carbon. 
 
 The oxidation of the sulphide of antimony may also be effected by igniting it with 
 mercuric oxide (prepared by precipitating a hot solution of mercuric chloride with 
 excess of caustic potash). When these substances are heated together in equivalent 
 proportions, a violent explosion takes place ; but if the sulphide of antimony be mixed 
 with between thirty and fifty times its weight of mercuric oxide, the oxidation takes 
 place quietly. The mixture is heated in a porcelain crucible, gently, so long as mer- 
 curial vapours go off, afterwards more strongly, and at last very strongly, to expel the 
 last traces of mercury. Antimonate of antimony then remains in the form of a soft 
 white powder. As mercuric oxide, even when prepared with the greatest care, always 
 leaves a small residue when ignited, the amount of this residue must be determined 
 once for all, and the proportionate amount deducted from the weight of the antimonate 
 of antimony. As, however, this residue never exceeds a few thousandths of the whole, 
 it is not necessary to weigh the oxide of mercury with great exactness. In this pro- 
 cess, it is necessary, if the sulphide of antimony contains a large excess of free sulphur, 
 to remove that substance by washing with bisulphide of carbon, before proceeding to the 
 ignition; because free sulphur, even when ignited with a large excess of mercuric 
 oxide, produces explosions which might occasion loss. The method just described has 
 been lately introduced by Bu n s e n (Ann. Ch. Pharm. cvi. 3). It is quite exact, provided 
 due attention be paid to the precautions above indicated. 
 
 2. The precipitated sulphide of antimony is collected on a weighed filter, dried in 
 an oil-bath, at about 120 C., and then weighed. A known portion of it is then either 
 decomposed by ignition in an atmosphere of hydrogen, whereby the sulphur is expelled 
 
ANTIMONY: ESTIMATION. 321 
 
 in the form of hydrosulphuric acid, and metallic antimony remains: or a weighed 
 portion of the sulphide is oxidised by means oi hydrochloric acid and chlorate of potas- 
 sium, the action being continued till the greater part of the sulphur is converted into 
 sulphuric acid, and the remainder collected at the bottom of the liquid in a melted 
 globule. The liquid is then diluted with water containing tartaric acid, to prevent 
 the precipitation of a basic salt of antimony, and decanted ; the globule of sulphur* 
 washed and weighed, and the quantity of sulphur in solution estimated as sulphate of 
 barium (see SULPHUR), the quantity thus found being added to the weight of the 
 globule. The proportion of sulphur in the precipitated sulphide of antimony being 
 thus found, the amount of antimony is easily calculated. Antimony cannot be accu- 
 rately estimated by merely weighing the precipitated sulphide, because the precipitate 
 almost always contains free sulphur, and sometimes pentasulphide of antimony in 
 unknown proportion. 
 
 When antimonious and antimonic acids exist together in solution, the total quantity 
 of antimony may be estimated by treating one portion of the liquid as above described, 
 and the quantity existing as antimonious acid determined in another portion by means 
 of trichloride of gold, 4 at. of precipitated gold corresponding to 3 at. of antimony 
 (p. 313). 
 
 Atomic Weight of Antimony. Berzelius (Schw. J. xxii. 69) determined the 
 amount of tetroxide produced from a given weight of the metal by oxidation with 
 nitric acid, and thence found, for the atomic weight of antimony, the number 129-03. 
 The same process has more recently been followed by Dexter (Pogg. Ann. c. 579), 
 who found the smaller number 122'33 : but even this number is generally regarded as 
 too high, the error being supposed to arise from incomplete oxidation and the conse- 
 quent admixture of trioxide with the tetroxide. 
 
 The number at present most generally adopted is that determined by Schneider 
 (Pogg. Ann. xcviii. 293) from the analysis of the native trisulphideby hydrogen. Stib- 
 nite from Arnsberg, which consists of pure trisulphide of antimony mixed with only a 
 small quantity of quartz (about | per cent.), was decomposed by ignition in a stream 
 of hydrogen, and the reduced antimony weighed, the escaping gas being passed into 
 aqueous ammonia to absorb any sulphide of antimony that volatilised, and this 
 quantity being afterwards precipitated by hydrochloric acid, oxidised by fuming nitric 
 acid, and weighed as tetroxide (its quantity did not exceed 1 or 2 milligrammes). 
 Corrections were also made for the quartz in the mineral and for the small amount of 
 sulphide which remained unreduced and unvolatilised ; for which purpose the residue 
 in the reduction-tube was weighed, then digested in aqua-regia, the residual quartz 
 again weighed, the sulphur in the solution determined by precipitation as sulphate of 
 barium, and the amount of antimony in the residue thence determined (about 0'4 per 
 cent.) After making these corrections, the composition of the trisulphide (81)' 2 .S <1 ) was 
 found to be 71'480 Sb + 28*520 S = 100, whence, the atomic weight of sulphur being 
 32, that of antimony is : 
 
 *" - isfe 48 = 120 ' 30 - 
 
 This result agrees nearly with former determinations by H. Eose, and also with that 
 found by Weber (Pogg. Ann. xcviii. 455), from the analysis of trichloride of anti- 
 mony, viz. 1207. Dumas, by decomposing trichloride of antimony with a standard 
 solution of silver, finds for the atomic weight of antimony the number 122. (Ann. Ch. 
 Pharm. cxiii. 29.) 
 
 Valuation of Antimony Ores. To estimate the amount of antimony in the native 
 sulphide, the ore is carefully roasted, and then fused at a moderate heat with 1 to 
 3 pts. of black flux and about 25 per cent, of borax, the whole being covered with a 
 layer of common salt. The quantity of metal which can be thus extracted from the 
 sulphide does not exceed 54 to 64 per cent, the calculated quantity being 71 '5 per 
 cent. Or the sulphide is fused with iron filings (about 42 pts. iron to 100 of sulphide), 
 together with three times its weight of black flux, and about 25 per cent, of borax, the 
 whole being covered with a thick layer of common salt. This process yields 66 to 68 
 antimony from 100 pts. of the sulphide. 
 
 To estimate the amount of sulphide of antimony in a sample of the crude ore, the 
 ore, in pieces of about the size of a walnut, is heated in a hessian crucible perforated at 
 bottom, and standing on another crucible placed below the grate, and surrounded with 
 ashes or sand to^keep it cool. Care must be taken to avoid applying too much heat. 
 
 If the gangue is not attacked by hydrochloric acid, the amount of sulphide may be 
 estimated by boiling a weighed portion of the ore with that acid and weighing the 
 residue. (Kerl, Hiittenkunde, iii. 26.) 
 
 4. Separation of Antimony from other me tals. From the metals of the 
 second and third groups (see ANALYSIS, p. 213) antimony is separated by precipitation 
 
 VOL. I Y 
 
322 ANTIMONY: FLUORIDEIODIDE. 
 
 with hydrosulphuric acid ; from those of the first group, whose sulphides are insolub'e 
 in alkaline sulphides, it is separated by precipitating with hydrosulphuric acid and 
 digesting the precipitate in sulphide of ammonium. The sulphide of antimony then 
 dissolves, the other metals remaining undissolved; and on mixing the filtrate with 
 excess of hydrochloric or acetic acid, the sulphide of antimony is reprecipitated. When 
 hydrochloric acid is used, care must be taken to keep the liquid dilute and not allow it 
 to get hot, otherwise some of the antimony may be redissolved. 
 
 When antimony is combined with other metals in the form of an alloy, it may often 
 be separated by treating the alloy with moderately strong nitric acid, which dissolves 
 the other metals, leaving the antimony in the form of antimonic acid, which may then 
 be converted into antimonate of antimony by ignition. This method, however, is not 
 rigidly exact, because the nitric acid dissolves a small portion of the antimony ; but it 
 is near enough for commercial purposes. It is of course not applicable to the separa- 
 tion of antimony from tin, gold, or platinum. 
 
 The separation of antimony from tin may be effected by immersing in the solution a 
 piece of pure tin, which precipitates the antimony in the form of a black powder. To 
 render the separation complete, a gentle heat must be applied, and the solution should 
 contain an excess of acid. The antimony is collected on a weighed filter, dried at a 
 gentle heat, and weighed. If the sum of the weights of the two metals in the solution 
 is previously known, the amount of tin is at once determined by difference ; if not, the 
 metals must be precipitated together by zinc from a known quantity of the solution, and 
 the antimony precipitated by tin from another portion. Another method of separa- 
 tion given by Levol (Ann. Ch. Phys. [3] xiii. 125) is, to precipitate the two metals by 
 zinc, and treat the precipitate with strong hydrochloric acid, without previously decanting 
 the solution of chloride of zinc. The tin then dissolves, while the antimony remains 
 undissolved, the presence of the chloride of zinc diminishing its tendency to dissolve 
 in the acid. The tin may be afterwards precipitated by hydrosulphuric acid, and the 
 sulphide converted into stannic oxide by treating it with strong nitric acid. 
 
 For the separation of antimony from arsenic, gold, and platinum, see those metals. 
 From selenium and tellurium, antimony is separated in the same manner as arsenic (q. v.) 
 
 AWTIMOKTH-, FLUORIDE OP. SbF 3 . Obtained by dissolving the trioxide in 
 hydrofluoric acid. It forms colourless crystals, which dissolve completely in water 
 without decomposition. 
 
 GZiASS OP. See ANTIMONY, OxYSTTTPHIDE OF. 
 
 HYDRIDE OP, or ATffTUVTOWIDE OP HZBROGEW, 
 
 generally called Antimonetted or Antimoniurctted hydrogen SbH 3 . When an anti- 
 mony-compound, tartar-emetic for example, is introduced into an apparatus in which 
 hydrogen is generated by the action of zinc or dilute sulphuric acid, the flame pro- 
 duced by the combustion of the gas at the orifice of the jet, acquires a bluish tinge 
 from admixture of antimonide of hydrogen. This compound may be obtained in a 
 state of greater purity by dissolving an alloy of 2 pts. of zinc and 1 pt. of antimony 
 in hydrochloric or dilute sulphuric acid. It is always, however, more or less con- 
 taminated with free hydrogen. 
 
 It is a colourless gas, and when free from arsenic, quite inodorous ; insoluble in 
 water and in alkaline liquids. ^ When it is passed into hot concentrated nitric acid, a 
 white powder is deposited, consisting of antimonic acid. When passed into a solution 
 of nitrate of silver or chloride of mercury, it forms a black precipitate, containing the 
 whole of the silver or mercury. The silver-precipitate has been found to be SbAg 3 , 
 and is formed by simple substitution of silver for hydrogen. Hence the antimonide 
 of hydrogen is inferred to be SbH 3 , analogous to ammonia, and to arsenide and phos- 
 phide of hydrogen, AsH 3 and PH 3 . 
 
 When antimonide of hydrogen is passed through a tube of hard glass and strongly 
 heated by the flame of a lamp, it is decomposed, and a mirror of metallic antimony is 
 deposited on the tube. If a funnel be held over the flame of the gas, a deposit of 
 trioxide of antimony is formed on its inner surface. A cold porcelain dish held in the 
 middle of the flame, becomes covered with spots of metallic antimony, which are darker 
 in colour' than those formed in a similar manner by arsenic, and are further dis- 
 tinguished from the latter by not dissolving in hypochlorite of sodium. The antimony 
 deposit dissolves easily in aqua-regia and in permanganate of potassium, and the 
 solution thus formed exhibits the characteristic reactions of antimony with hydro- 
 sulphuric acid, &c. (p. 319). 
 
 There are several compounds of antimony with alcohol-radicles, analogous to 
 antimonetted hydrogen, viz. stibtrimethyl, Sb(CH s ) 3 , stibtriethyl, Sb(C 2 H 5 ) 3 , and stib- 
 triamyl, Sb(C 5 H u ) 8 . 
 
 ANTIIVCOTJY, XODIDS OP. Sbl 3 . Prepared like the bromide. It is a dark 
 red body, decomposed by water, forming an oxyiodide. The sulphiodide, Sb 2 I 2 S 3 , is 
 
ANTIMONY: ORES AND OXIDES. 323 
 
 obtained as a red sublimate, by heating an intimate mixture of iodine and the 
 trisulphide in a retort. It is decomposed by water, yielding hydriodic acid and an 
 oxysulphide. 
 
 AWTI1V10N-Y, ORES OP. See p. 311 ; for the valuation, p. 321. 
 
 ANTIIVIOM'Y, OXIDES OP. Antimony forms with oxygen three definite com- 
 pounds, viz. : the 
 
 Trioxide or Antimonious oxide ..... Sb 2 8 or SbO* 
 Tetroxide or Antimonoso-antimonic oxide . . . Sb 2 4 or SbO* 
 Pentoxide or Antimonic oxide ..... Sb 2 5 or 
 
 The tetroxide is perhaps a compound of the other two, Sb s 3 .Sb-0 5 = 2Sb 2 0*. A 
 suboxide Sb 2 (?) is also said to be produced, as a grey film, when antimony is used as 
 the positive pole in the electrolysis of water. It appears, however, to be merely a mix- 
 ture of the metal with the trioxide, for, when treated with hydrochloric acid, it yields 
 solution of the trioxide and a residue of antimony. (Berzelius.) 
 
 TRIOXIDE OF ANTIMONY, or ANTIMONIOUS OXIDE, Sb 8 3 , occurs, though 
 rarely, as a natural mineral (Valcntinite, White Antimony, Antimony-bloom, Weiss- 
 piessglanzerz}, in shining white crystals belonging to the trimetric system; specific 
 gravity 5*566 hardness; 2'5 3. It occurs in veins of primary rocks at Przibram in 
 Bohemia, at Braunsdorf in Saxony, and at Malaczka in Hungary. It is found also 
 in regular octahedrons, viz. as Scnarmontite, a mineral from the GHied Hamimim 
 mine, in the province of Constantine, Algeria : it is therefore dimorphous. This oxide 
 is formed when the metal burns in the air, and may be prepared by heating antimony 
 in a crucible imperfectly closed with its cover : it is then deposited on the sides of the 
 crucible, a little above the melted metal, in shining prismatic crystals, known by the 
 name of flowers of antimony, flores antimonii argentei. But the easiest mode of obtain- 
 ing it is, to heat the trisulphide with strong hydrochloric acid as long as hydrosulphuric 
 acid continues to escape, and pour the resulting solution of the trichloride into a 
 boiling solution of carbonate of sodium. A crystalline powder is then deposited, 
 consisting (according to Graham) of the anhydrous trioxide: 
 
 2SbCP + 3Na 2 C0 3 = Sb 2 3 + 6NaCl + 3C0 2 . 
 
 Eegnault, however, states (Cours de Chimie, iii. 239) that the oxide thus obtained is 
 a hydrate, containing Sb 2 3 .H 2 or SbHO 8 . The trioxide is likewise obtained, though 
 mixed more or less with antimonic acid, by treating metallic antimony with nitric 
 acid (p. 318). 
 
 The artificial as well as the native trioxide of antimony is dimorphous. The 
 crystals produced by the rapid oxidation of the metal belong to the trimetric or right 
 prismatic system. Sometimes, however, when the oxide is sublimed at a comparatively 
 low temperature, as when a few ounces of antimony are heated till the metal begins 
 to burn, and then left to cool slowly, the prismatic crystals are mixed with regular 
 octahedrons. According to Mitscherlich (Ann. Ch. Phys. [2] xxxiii. 394) the 
 trioxide is also deposited in regular octahedrons from a solution in boiling soda. In 
 each of its forms, it is isomorphous with one of the forms of trioxide of arsenic 
 (arsenious oxide) : the two bodies are therefore isodimorphous. Antimonious oxide is 
 white or grey isli- white at ordinary temperatures, but turns yellow when heated. It 
 melts below a red heat, and sublimes when raised to a higher temperature in a close 
 vessel. When heated in the air, it is partly converted into antimonic oxide. It is 
 not decomposed by heat alone, but is reduced to the metallic state when heated with 
 hydrogen, charcoal, or potassium. 
 
 Trioxide of antimony dissolves sparingly in water, more freely in strong hydro- 
 chloric acid; the latter solution is quite clear, provided the oxide is free from 
 antimonic acid, but is rendered turbid by dilution with water. It dissolves when 
 boiled with aqueous tartaric acid, and very easily in a solution of acid tartrate of 
 potassium (cream of tartar) ; forming the tartrate of antimony and potassium, or tartar- 
 emetic, C 4 H 4 KSb0 7 . (See TARTRATES.) 
 
 It is quite insoluble in nitric acid of ordinary strength ; but dissolves in cold fuming 
 nitric acid, forming a solution which deposits pearly scales of a nitrate, N 2 5 .2Sb"0 3 
 (Peligot). It dissolves also in fuming sulphuric acid, the solution depositing 
 shining scales of a sulphate containing 3S0 3 .Sb i: 3 . It does not absorb carbonic acid; 
 indeed, no carbonate of antimony is known to exist. 
 
 Trioxide of antimony acts as a feeble acid, forming salts called antimonites. 
 The precipitated trioxide dissolves easily in alkalis, but the resulting compounds are 
 very unstable, being decomposed by mere evaporation. The solutions give with nitrate 
 of silver and excess of ammonia, a black precipitate insoluble in free ammonia. They 
 reduce trichloride of gold, precipitating the metal. More stable salts, the anti- 
 
 y 2 
 
324 ANTIMONY: OXIDES. 
 
 inonoso-antimonates, are formed by the union of the antimonitos with antimonates 
 (vid. inf.). The trioxide fused with caustic alkalis or their carbonates is converted 
 into antimonic acid, which unites with the alkali. (Fremy.) 
 
 TETROXIDE OF ANTIMONY, or Antimonoso-antimonic oxide, sometimes 
 called Antimonious acid, Sb 2 4 . This oxide is found native, as Cervantitc or Antimony- 
 ochre, forming acicular crystallisations, or massive, or as a crust or powder. It is 
 yellow, or nearly white, of a greasy, bright or earthy lustre, and specific gravity 
 4-084. It is found at Pereta, in Tuscany (Dana, iii. 141). The same oxide is pro- 
 duced by the action of heat upon antimonic oxide (Sb-0 5 ), by roasting the trioxide or 
 trisulphide, or by treating pulverised antimony witli excess of nitric acid. As thus 
 prepared, it is white, infusible, and unalterable by heat; slightly soluble in water, 
 more soluble in hydrochloric acid. It is easily resolved into antimonious and anti- 
 monic oxides. On boiling it with acid tartrate of potassium (cream of tartar) anti- 
 monious oxide dissolves, and antimonic oxide is left behind ; and when a solution of the 
 tetroxide in hydrochloric acid is gradually dropped into a large quantity of water, a 
 precipitate of antimonious oxide is first produced, while antimonic acid remains in 
 solution. From these and similar reactions, it has been inferred that the tetroxide is a 
 compound of the trioxide and pentoxide, or an antimonate of antimony (Sb 2 3 + 
 Sb 8 5 = 2Sb 2 4 ). On the other hand, it is sometimes regarded as a distinct oxide, 
 because it dissolves in alkalis, forming salts (often called antimonites), which may 
 be obtained in the solid state. By fusing the tetroxide with hydrate or carbonate of 
 potassium, exhausting with cold water, treating the residue with boiling water, and 
 evaporating to dryness, a yellow, uncrystalline, saline mass is obtained, composed of 
 K 2 O.Sb 2 4 , and by mixing the solution of this salt with a small quantity of hydro- 
 chloric acid, a more acid salt, K 2 0.2Sb 2 4 is precipitated. By treating the same 
 solution with a large quantity of acid, a precipitate is formed, consisting of the 
 hydrated tetroxide, H 2 O.Sb 2 4 . It is, however, more in accordance with the reactions 
 above-mentioned, to regard these salts as antimonoso-antimonates, that is to say, 
 as compounds of antimonates (containing Sb 2 5 ) with antimonites (containing Sb*0 3 ) ; 
 thus the salt, K 2 O.Sb 2 4 , maybe regarded as (K 2 O.Sb 2 8 ) + (K 8 O.Sb 2 5 ), or KSbO 2 . 
 KSbO*. 
 
 The antimonoso-antimonates of the earth-metals and heavy metals are insoluble in 
 water, and may be obtained by precipitation. Two of them are known as natural 
 minerals, viz. 1. Bomcinc, or (so-called) Antimonite of calcium, found at St. Marcel, . 
 in Piedmont, in groups of minute square-based octahedrons, of hyacinth-red, or 
 honey-yellow colour; specific gravity 4*714 (in powder 4*675), hard enough to scratch; 
 glass. It contains 62'18 per cent, antimony, 15*82 oxygen, 16*29 lime, 1*31 iron, 1*21 
 protoxide of manganese, and 2'86 silica. The formula, 3Ca*0.2Sb 2 4 , requires 61*9 
 per cent., Sb, 22'7 0, and 15'4 Ca (Dana, ii. 410). 2. Ammiolitc, or (so-called) Anti- 
 monite of mercury, occurs, mixed with clay and hydrated sesquioxide of iron, in the 
 quicksilver mines in Chili, and at Silberg, near Olpe in Westphalia. It is a red 
 powder, containing, according to Domeyko (Ann. Min. [4] vi. 183), 12*5 per cent. 
 Sb 2 4 , 14-0 Hg 2 0, 22-3 Fe 4 3 , 26'5 SiO 2 , and 247 water (and loss). Probably only a 
 mixture. (Dana, ii. 142.) 
 
 PENTOXIDE OF ANTIMONY, ANTIMONIC OXIDE or ANHYDRIDE, Sb 2 5 . 
 In the hydrated state : ANTIMONIC ACID. This compound is obtained as a hydrate : 
 
 1. By treating antimony with nitric acid, or with aqua regia containing excess of 
 nitric acid. 2. By precipitating a solution of antimonate of potassium with an acid. 
 
 3. By decomposing pentachloride of antimony with water. 
 
 The hydrated oxide obtained by either of these methods gives off its water at a 
 heat below redness, and yields the pentoxide or anhydrous antimonic acid, as a 
 yellowish powder. The same body is obtained by heating pulverised antimony with 
 mercuric oxide till the green antimonate of mercury at first produced is decomposed 
 and all the mercury driven off. It is tasteless, insoluble in water and in acids, and 
 has a specific gravity of 6*6 (Bo u Hay). At a red heat, it gives off oxygen, and is 
 converted into the tetroxide. It is dissolved by boiling potash-ley, and when fused 
 with carbonate of potassium expels carbonic anhydride and forms a salt, from which 
 acids separate hydrated antimonic acid. 
 
 The hydrated oxides or acids obtained by the three methods above given, are by no 
 means identical. That obtained by the first and second method is monobasic, and ac- 
 cording to Berzel ius, contains Sb'-0 5 .H-Oor SbHO'; accordingto Fremy, Sb 2 5 .5H 2 O, 
 or S1)H 5 5 , when air-dried at mean temperature ; but the acid obtained by the action of 
 water on pentachloride of phosphorus is dibasic, and contains, accordingto Fremy, 
 Sb 2 5 .4H 2 0. The monobasic acid is called Antimonic acid; the dibasic acid, Mctanti- 
 monic acid. _ These acids are further distinguished by the following characters. Anti- 
 monic acid is a soft white powder, sparingly soluble' in wntcr, reddens litmus, and is 
 dissolved, even in the cold, by strong hydrochloric acid and by potash-ley. The hydro- 
 
ANTTMONATES. 325 
 
 chloric solution mixed with a small quantity of water, yields after a while, a precipi- 
 tate of antimonic acid, Init if diluted M r ith a large quantity of water, it remains clear. 
 Ammonia does not dissolve it in the cold. It is converted into metantimonic acid by 
 heating with a large excess of hydrate of potassium. Metantimonic acid dissolves in 
 acids more readily than antimonic acid, and is dissolved by ammonia, after a while, 
 even at ordinary temperatures. It likewise dissolves completely in a large quantity 
 of water, and is precipitated therefrom by acids. It is very unstable, and easily 
 changes into antimonic acid, even in water. 
 
 ANTLMONATES and METANTIMONATES. Antimonic acid forms neutral or normal 
 salts, containing M 2 O.Sb 2 5 or MSbO 3 , and acid salts containing M 2 0.2Sb 2 5 , or 
 Sb 2 0*.2MSb0 8 . Metantimonic acid, which is dibasic, forms normal salts containing 
 2M 2 O.Sb-0 5 , orMWO 7 , and acid salts containing 2M 2 0.2Sb 2 5 , or M 2 O.Sb 2 5 , so that 
 the acid metantimonates are isomeric or polymeric with the neutral antimonates.* An 
 acid metantimonate easily changes into a neutral antimonate (Fremy, Ann. Ch. 
 Phys. [3] xii. 316, 357; xxii. 404). Heffter (Pogg. Ann. Ixxxvi. 411) analysed a 
 series of antimonates, which, calculating from the old atomic weight of antimony 
 (119), he supposed to contain 12 at. Sb 2 5 to 13 at. of a base M'-'O ; but on recalculat- 
 ing the analyses with the new atomic weight (Sb = 120'3), it is found that they agree 
 with the general formula M 2 O.Sb 2 5 . 
 
 The metantimonates of ammonium, potassium, and sodium, are crystalline; the 
 antimonates of the same bases are gelatinous and unerystallisable . The soluble acid 
 metantimonates form a crystalline precipitate with sodium-salts ; the soluble antimo- 
 nates do not form any such precipitate. 
 
 The antimonates and metantimonates of the alkali-metals are the only ones that 
 are easily soluble in water. All the rest are insoluble or sparingly soluble, and may 
 be obtained by precipitation. 
 
 Antimonate of Aluminium. On adding the solution of an aluminium-salt to 
 excess of antimonate of potassium, the whole of the alumina is precipitated in com- 
 bination with antimonic acid, in white flocks,, somewhat soluble in excess of the 
 aluminium-salt. 
 
 Antimonate of Ammonium, (NH 4 ) 2 O.Sb 2 5 + 2H 2 Q, or (NH 4 )Sb0 3 + H 2 0, sepa- 
 rates as a white powder from a solution of antimonic or metantimonic acid in warm 
 aqueous ammonia. Neutral metantimonate of ammonium, 2(NH 4 ) 2 O.Sb 2 5 , is ob- 
 tained in solution by treating metantimonic acid with cold aqueous ammonia ; it is 
 not easily obtained in the solid state. The solution mixed with a drop or two of 
 alcohol, deposits a crystalline salt, which is the acid metantimonate of ammonium, 
 (NH*) 2 O.Sb'-'0 5 + 6II 2 0. This salt is soluble in water, and the solution precipitates 
 sodium-salts. It is very unstable, being converted, with loss of water, slowly at 
 ordinary temperatures, and immediately at the boiling heat, into the insoluble neutral 
 antimonate, with which it is isomeric. 
 
 /,Sb 2 O 3 .Sb 2 5 . The tetroxide of antimony is sometimes 
 regarded as constituted in this manner (p. 317). 
 
 Antimonate of Barium, Ba 2 O.Sb 2 5 , or BaSbO 3 , is obtained by double decom- 
 position, as a flocculent precipitate which gradually becomes crystalline ; it dissolves 
 slowly in aqueous chloride of barittm. 
 
 Antimonate of Calcium, Ca*O.Sb 2 5 , is a crystalline precipitate, which adheres 
 closely to the sides of the vessel, like carbonate of calcium. 
 
 Antimonate of Cobalt, Co*O.Sb 2 O 5 . Reddish" crystalline precipitate, which, 
 when heated, gives off water, turns violet, and then black ; when heated to redness, it 
 becomes incandescent, and on cooling appears nearly white. By mixing a solution of 
 sulphate of cobalt with a hot solution of antimonate of sodium, Heffter (loc. cit.) 
 obtained a flocculent rose-coloured precipitate, containing Co 2 O.Sb 2 O s + 7H 2 0, and 
 the mother-liquor, after standing for some days, deposited six-sided prisms containing 
 Co 2 O.Sb 2 5 + 12IFO. 
 
 Antimonate of Copper, Cu 2 O.Sb 2 5 , or CuSbO 8 , is a greenish crystalline powder, 
 which when heated gives off 19| per cent, water, and turns black. At a red heat, it 
 glows like the cobalt-salt, turns white, and is afterwards unattackable by acids or alkalis 
 in solution. On charcoal before the blowpipe, it is reduced to antimonide of copper. 
 
 Antimonates of Iron. The ferrous salt is a white powder which becomes yel- 
 lowish grey when dry, red by ignition, and is sparingly soluble in water. The/e-mc 
 salt is light yellow. 
 
 Antimonate of Lead, Pb 2 O.Sb 2 5 , or PbSbO 3 , is obtained as a yellow anhydrous 
 powder by fusing pentoxide of antimony with oxide of lead, or as a white hydrate by 
 precipitation ; the hydrate gives off its water when heated, and turns yellow. 
 
 * If = S, the formula; of the neutral and acid antimonates are AfO.SbO* and A/0.2S60 S , and of the 
 metautimonates, ZMO.SbO* and 2Jtf0.2S6O 9 respectively. 
 
326 ANTIMONATES. 
 
 A basic antimonate of lead, known by the name of Naples Yellow, is much used in 
 oil-painting. It is obtained of the finest colour by mixing 2 pts. of chemically pure 
 nitrate of lead with 1 pt. of the purest tartar-emetic and 4 pts. of common salt puri- 
 fied by repeated crystallisation, exposing the mixture for two hours to a heat just 
 sufficient to fuse the chloride of sodium, and dissolving out the chloride of sodium 
 with water ; if the temperature has not been allowed to rise too high, the Naples 
 yellow is then obtained in the form of a fine powder. The same pigment is likewise 
 obtained, but generally of a less brilliant colour, by fusing equal parts of antimony 
 and lead with 3 pts. of nitre and 6 pts. of common salt. 
 
 Another basic antimonate of lead, 3Pb 2 O.Sb 2 5 + 4H 2 0, occurs native at Nerts- 
 chinsk in Siberia, forming the mineral Blcinicrite. It is amorphous, reniform, sphe- 
 roidal ; also earthy or incrusting ; sometimes with curved lamellar structure, specific 
 gravity 3-933 (Karsten); 4-6476 (Hermann). Lustre resinous, dull, or earthy. 
 Colour grey, brownish, or yellowish. Opaque. Streak, greyish or yellowish. It is 
 perhaps a mechanical mixture of lead and antimony ochres, and appears to result from 
 the decomposition of other ores of antimony. (Hermann, J. pr. Chem. xxxiv. 179.) 
 
 Antimonate of Lithium. Obtained by mixing a concentrated solution of 
 chloride of lithium with antimonate of potassium, in flocks which soon become crys- 
 talline. It dissolves easily in hot water, and separates in grains on cooling. In 
 dilute solutions, no precipitate is obtained. 
 
 Antimonate of Magnesium, Mg 2 O.Sb 2 5 + 12H 2 0. Separates by double 
 decomposition from boiling solutions, in colourless shining hard crystals, which are 
 isomorphous with the corresponding cobalt-salt, give off 8 per cent, water at 100 C., 
 10 per cent, at 200, and 11 per cent, at 300. (Heffter.) 
 
 Antimonate of Manganese. White, altered by exposure to the air, sparingly 
 soluble in water, . somewhat more soluble in excess of the manganous salt. At a red 
 heat, it becomes unattackable by acids, but does not glow. 
 
 Mercuric Antimonate, Hg 2 O.Sb 2 5 , or HgSbO 3 , is obtained by double decom- 
 position as an orange-yellow precipitate. There is also an olive-green mercuric 
 antimonate obtained by heating to low redness a mixture of 1 pt. powdered antimony, 
 and 6 or 8 pts. mercuric oxide. At a stronger heat, this salt gives off oxygen and 
 mercury, and leaves antimonic oxide. It is biit little attacked by acids ; but boiling 
 hydrochloric acid dissolves a small quantity of it, and ammonia added to the solution 
 throws down a light green powder. 
 
 Antimonate of Nickel. Sulphate of nickel mixed with a boiling solution of anti- 
 monate of potassium, immediately forms a light green flocculent precipitate containing 
 Ni-O.Sb 2 5 + 6H 2 0, and the mother-liquor, after a few days, yields crystals of darker 
 colours isomorphous with the magnesium-salt and analogous to it in constitution. 
 
 Antimonates of Potassium. The neutral salt, K 2 O.Sb 2 5 + 5H 2 0, is obtained 
 by fusing 1 pt. of antimony with 4 pts. of nitre, digesting the fused mass in tepid 
 water to remove nitrate and nitrite of potassium, and boiling the residue for an hour 
 or two with water. The white insoluble mass of anhydrous antimonate is thereby 
 transformed into a hydrate containing 5 at. water, which is soluble. The solution, 
 when evaporated, leaves this hydrate in the form of a gummy uncrystallisable mass, 
 which gives off 2 at. of water at 160 C., and the whole at a higher temperature. 
 According to Heffter the anhydrous neutral antimonate is partly decomposed by pro- 
 longed boiling with water, an acid salt 2K 2 O.Sb 2 5 remaining undissolved, and the 
 liquid filtered therefrom yielding by evaporation the neutral salt with 7 at. water : 
 5 + 7H 2 0. 
 
 Acid Antimonate of Potassium is obtained by passing carbonic acid gas through a 
 solution of the neutral antimonate. It is white, crystalline, perfectly insoluble in 
 water, and is converted into the neutral salt when heated with excess of potash. This 
 salt is the antimonium diaphoreticum lavatum of the pharmacopeias. (Fremy.) 
 According to Heffter, the salt thus obtained is 2K 2 O.3Sb 2 5 + 10H 2 0. 
 
 Neutral Mctantimonate of Potassium is prepared by fusing antimonic oxide or neutral 
 antimonate of potassium with a large excess of potash. The fused mass dissolves in a 
 small quantity of water, and the solution evaporated in vacuo yields crystals of the 
 neutral metantimonate. This salt dissolves freely and without decomposition in warm 
 water containing excess of potash ; but cold water or alcohol decomposes it into potash 
 and the acid matantimonate, Hence the aqueous solution of this salt gives a pre- 
 cipitate, after a while, with salts of soda. (Fremy.) 
 
 Acid Metantimonate of Potassium, K 2 O.Sb 2 5 + 7H 2 0, sometimes called granular 
 antimonate of potassium. This salt is used as a test for soda. To obtain it, the 
 neutral antimonate is first prepared and dissolved in the manner above described; the 
 
ANTIMONY: OXYCHLORIDE. 327 
 
 solution is filtered to separate any acid antimonate that may remain undissolved, then 
 evaporated to a syrup in a silver vessel ; and hydrate of potassium is added in lumps to 
 convert the antimonate into metantimonate. The evaporation is then continued till 
 the liquid begins to crystallise, which is ascertained by taking out a drop now and 
 then upon a glass rod, and the liquid is then left to cool. A crystalline mass is thus 
 obtained, consisting of neutral and acid metantimonate of potassium ; the alkaline 
 liquor is then decanted, and the salt dried upon filtering paper or unglazed porcelain 
 (Fremy). This salt may also be prepared by treating trichloride of antimony with 
 an excess of potash sufficient to redissolve the precipitate first formed, and adding 
 permanganate of potassium till the solution acquires a faint rose colour. The liquid, 
 filtered and evaporated, yields crystals of the granular metantimonate (Reynoso). 
 This salt is sparingly soluble in cold water, but dissolves readily in water, between 
 45 and 50 C. When boiled with water for a few minutes, or kept in contact with 
 water for some time, it is converted into the neutral antimonate. It must therefore be 
 preserved in the solid state, and dissolved just before it is required for use. A small 
 quantity of it is then treated with about twice its weight of cold water, to remove 
 excess of potash, and convert any neutral metantimonate into the acid salt; the 
 liquid is decanted ; and the remaining salt is rapidly washed three or four times with 
 cold water, then left in contact with water for a few minutes, and the liquid is filtered. 
 On adding to the solution thus obtained a small quantity of any sodium-salt, a crystal- 
 line precipitate is formed, consisting of acid metantimonate of sodium (vid. inf."). 
 
 Antimona te of Sodium is obtained in tabular aggregates of small crystals, when 
 the wash-water, resulting from washing a deflagrated mixture of antimony and nitre, 
 is mixed with a sodium-salt. This salt has, according to Fremy, the composition 
 Na 2 O.Sb 2 5 + 7H 2 0. A salt of the same constitution is obtained, according to 
 Heffter, in regular octahedrons, by boiling golden sulphide of antimony with caustic 
 soda, and filtering the aqueous extract. It is nearly insoluble in cold water, soluble 
 in about 350 pts. of boiling water. It gives off 2 at, water at 200 C., 2 at. more at 
 300, and the rest at a red heat. 
 
 Acid Metantimonate of Sodium, Na 2 O.Sb 2 5 + 7H 2 0, or 2NaHO.Sb 2 5 + 6H 2 0. 
 This salt is produced when a solution of acid metantimonate of potassium, free from excess 
 of alkali, is added to the solution of a sodium-salt. If the solution is not very dilute 
 the precipitate is flocculent at first, but soon becomes crystalline. It is produced 
 immediately in solutions containing not less than 1 pt. of sodium-salt in 300 pts. of 
 liquid. In more dilute solutions, the precipitation is gradual, the metantimonate of 
 sodium being deposited in crystals on the sides of this vessel, the effect being apparent 
 after twelve hours, even in solutions containing not more that j~ pt. of sodium-salt. 
 The precipitation is accelerated and rendered more complete by adding a little alcohol. 
 The presence of free alkali retards it. The solution of sodium to be tested in this 
 manner should be free from salts of lithium, ammonium, and the earth-metals, all of 
 which, when diluted to a certain extent, yield precipitates of similar character. Acid 
 metantimonate of sodium gives off 6 at. of water at 100C.,the seventh at about 300. 
 
 Antimonate of Strontium. Amorphous precipitate containing Sr ? O.Sb 2 5 + 
 6H 2 0. 
 
 Antimonate of Zinc, Zn'-O.Sb 2 5 . Crystalline precipitate somewhat soluble in 
 excess of the zinc-salt. When heated, it gives off water and turns yellow, but without 
 incandescence. On charcoal before the blowpipe it does not fuse ; neither is it 
 reduced without addition of alkali. 
 
 ANTXiviOire, OXYCHLORIDE OP. Basic Chloride of Antimony, Powder 
 of Algaroth, Pulvis Algaroiki s. angelicus, Mcrcurius Titcs, &c. A compound formed 
 by the action of water on trichloride of antimony. It was formerly much used in 
 medical practice, but now serves chiefly for the preparation of pure antimonious 
 oxide and tartar-emetic. The best way of preparing it is to boil commercial sulphide 
 of antimony in fine powder with strong hydrochloric acid, till the liquid is saturated, 
 sulphuretted hydrogen escaping all the while ; leave the solution to cool ; add to it, 
 with agitation, small portions of water till it begins to show turbidity ; then filter ; 
 mix the filtrate with five to ten times its bulk of water; and wash the resulting pre- 
 cipitate thoroughly with cold water by decantation or on the filter. The addition of 
 a small quantity of water and filtration before the complete precipitation, is neces- 
 sary, in order to remove a small quantity of hydrosulphuric acid, which always remains 
 in the acid liquid, but is carried down by the first portions of oxy chloride precipitated, and 
 thereby removed : if allowed to remain, it would cause the precipitate to turn yellow. 
 
 The dried precipitate is a heavy white amorphous powder ; but if left to stand in 
 the liquid, or if boiled with it, is converted into a mass of small shining oblique rect- 
 angular pi-isms. It varies in composition according to the temperature of the water 
 used for the precipitation and washing. According to Duflos and Bucholz, it is 
 
 Y 4 
 
328 ANTIMONY: OXYIODIDE SELENIDE. 
 
 2ShCl 3 .5Sb 2 3 ; according to Johnston, 4SbCl 3 .9Sb 2 3 ; according to Schneider, 
 2.SbOCl.Sb 2 O s ; according to Peligot, the precipitate formed in the cold is SbCl 3 . 
 Sb-0 3 , or SbO.Cl, (chloride of antimonyl), and after it has become crystalline by 
 heating, 2SbCl 3 .5Sb 2 3 . Continued washing with water removes more and more of 
 the chloride, ultimately leaving nearly pure antimonious oxide; alkaline-water removes 
 the whole of the chloride. The oxychloride is also decomposed by heat, the chloride 
 being volatilised and oxide remaining. 
 
 Antimonious oxide dissolves in about 15 times its weight of the boiling trichloride, 
 and the solution on cooling solidifies into a pearly grey, perfectly crystalline mass, 
 apparently consisting of Sb 2 OCl 4 .6SbCl 3 , analogous to the sulphochloride formed in 
 like manner (p. 338). It is decomposed by absolute alcohol, with separation of powder 
 of algaroth. (Schneider, Pogg. Ann. cviii. 407.) 
 
 OXYIODIDZ OF. Antimonious iodide is decomposed by water, 
 yielding a white precipitate, which appears to be analogous in composition to the 
 oxychloride. An oxy iodide, 2SbI 3 .5Sb 2 3 , is likewise obtained in gold-coloured 
 spangles resembling iodide of lead, by adding iodine to a solution of tartar-emetic, OP 
 by treating the trichloride of antimony with solution of iodide of potassium, evaporat- 
 ing the solution, treating the residue with water, and repeating these operations 
 several times. It is decomposed by heat. Hydrochloric acid dissolves it, with sepa- 
 ration of iodine. It is slightly soluble in tartarie acid and cream of tartar. Nitric 
 acid decomposes it, separating oxide of antimony. (Preuss, Pharin. Centr. 1839, 
 p. 311.) 
 
 ANTIMONY, OXYSITX.PHIBE OP. The compound Sb 2 3 .2Sb 2 S 3 occurs native 
 as Red antimony, Antimony blende, Kcrmcsomc, Rothspiesscjlanzerz, in needles or tufts 
 of capillary crystals belonging to the monoclinic system : Specific gravity = 4'5 to 4 '6. 
 Hardness = 1 to To. It has a cherry-red colour and adamantine lustre, gives a 
 brownish-red streak, and is slightly translucent, appearing scarlet by transmitted light. 
 Melts very readily before the blowpipe, sinking into the pores of the charcoal, and 
 volatilising in dense clouds. Ignited in a current of hydrogen, it yields hydrosulphuric 
 acid, water, and metallic antimony (H. Rose, Pogg. Ann. iii. 452). It contains 74*5 to 
 747 Sb, 5-29 to 47 0, and 20*5 S. Occurs in veins in quartz, accompanying grey and 
 white antimony, at Malaczka near Posing in Hungary, at Braunsdorf near Freiberg, 
 and at Allemont in Dauphiny. It appears to result from alteration of grey antimony 
 ore. A similar compound, but of an orange-red colour and containing only 17'9 per 
 cent, sulphur, sublimes when aqueous vapour is passed over the ignited trisulphide. 
 (Regnault.) 
 
 Various oxysulphides of antimony may be prepared artificially. They were formerly 
 much used in pharmacy for the preparation of tartar-emetic, but are now nearly obso- 
 lete. a. Antimonial crocus or saffron (Crocus antimonii, s. mctallorum) is a brownish- 
 yellow substance, prepared by fusing a mixture of 3 pts. of the trioxide and 1 pt. tri- 
 sulphide of antimony, or an oxide of antimony with the proper proportion of sulphur. 
 A similar compound, mixed however with variable quantities of antimonite of potassium, 
 is obtained by treating the trisulphide with caustic alkalis (p. 332). 0. Glass of anti- 
 mony ( Vitrum antimonii) is an oxysulphide prepared by roasting the grey sulphide at a 
 moderate heat, till it is converted into the tetroxide, and fusing this antimony ash in 
 an earthen crucible, with about ^ of its weight of sulphur. It is a brilliant sub- 
 stance, varying in colour from yellowish-red to hyacinth-red, according to the propor- 
 tions used. It gives up its oxide to acids, and evolves sulphuretted hydrogen when 
 treated with hot hydrochloric acid. 7. A compound of trisulphide of antimony with a 
 very small portion of oxide, called Rcgulus antimonii medicinalis or Rubinus antimonii, 
 is obtained by fusing 5 pts. of the grey sulphide with 1 pt. of pearl-ash, and sepa- 
 rating the upper stratum (consisting of sulphantimonite of potassium) from the lower. 
 It is a black mass, having a brilliant conchoidal fracture, and yielding a dark grey 
 powder. 
 
 According to Liebig, mineral kermes prepared by the action of alkaline carbonates 
 on the amorphous trisulphide, is a definite oxysulphide of antimony (see p. 328) ; but 
 kermes obtained by most other modes of preparation, appears to contain the oxide 
 merely in a state of mixture with the sulphide. 
 
 ANTIMONY, SBXiENXDX: OP. Antimony and selenium unite when heated 
 together, to a lead-grey crystalline mass, the combination being attended with rise 
 of temperature, often amounting to ignition. The same compound is formed by pre- 
 cipitating a solution of tartar-emetic with seleniuretted hydrogen ; hence its formula 
 is probably SlrSe 3 . Selenide of antimony is easily fusible, and oxidises when heated 
 in the air, giving off selenious acid, Heated with trioxide of antimony, out of contact 
 with the air, it melts into a muss resembling the fused sulphide. 
 
ANTIMONY: SULPHIDES. 
 
 329 
 
 AKTTXlVIOira, SULPHIDES OP. Antimony forms . two sulphides, Sb 2 S 2 and 
 Sb 2 S 5 , corresponding to antimonious and to antimonic oxide, and perhaps also an 
 intermediate sulphide corresponding to the tetroxide. 
 
 TRISULPHIDE OF ANTIMONY, ANTIMONIOUS SULPHIDE, ANHYDROUS 
 SULPHA.NTIMONIOUS ACID, 8b 2 S 3 ,or SbS 3 . This compound exists in the crystalline 
 and in the amorphous state. 
 
 1. The crystallised trisulphide occurs as a natural mineral called stibnite, stibine, grey 
 antimony, antimony-glance (Spicssglanz, Grauspiessglanzerz, Antimoine sulfure, Leo 
 riibcr, Plumbum nigrum, Lupus metalloruni). It is the source of all the antimony of 
 commerce. It is found in various localities in Hungary, Germany, and France, also 
 in Cornwall, in Dumfriesshire, in Maine, Maryland, ar.d New Hampshire (U. S.), and 
 abundantly in Borneo, always associated with the older rocks, such as gneiss, quartz, 
 clay-slate, mica-slate, limestone, porphyry, &c., whence it is separated by simple 
 fusion, yielding the crude antimony of commerce. 
 
 The separation of the sulphide from the accompanying gangue is effected in various 
 ways. The simplest arrangement is that which is in use at Malbosc in the depart- 
 ment of Ardeche, in France, and at Wolfsberg in the Harz. A number of conical pots, 
 perforated at bottom, and standing upon receivers sunk in the ground, are placed 
 twenty -five or thirty in a row, between walls about nine inches high, the space be- 
 tween the pots being filled with coal, and the fire lighted with brushwood. Each pot 
 holds about 45 kilogrammes of ore, and in forty hours four meltings are made, suffi- 
 cient to fill the receivers. The advantages of this method are that it saves the ex- 
 pense of erecting a furnace, and may be carried on at any place to which the ore and 
 fuel can be most easily transported. But it involves a large consumption of fuel, and 
 is therefore advantageous only where fuel is very abundant. At Malbosc the con- 
 sumption is 300 kilogrammes of coal and 40 kil. of wood, for every 100 kil. of crude 
 antimony produced. 
 
 Another method, somewhat different from the above, consists in heating the conical 
 pots by the flame of a reverberatory furnace, the receivers being placed below the 
 hearth. This arrangement is also in use at Wolfsberg, and at La Lincouln in Haute 
 Loire. At Schmollnitz in Hungary, the pots are likewise heated by a reverberatory 
 furnace ; but the melted sulphide runs through a channel into receivers placed outside 
 the furnace. This arrangement effects a considerable saving of time and fuel, as it 
 enables the pots to be filled and emptied without putting out the fire. 
 
 In some localities, cylindrical tubes are used in preference to conical pots, as being 
 more durable. An arrangement of this 
 
 kind is in use at Malbosc. The ore Fig. 71. 
 
 is placed in large cylinders E B (fig. 
 71) each holding 500 pounds of ore, 
 and four being heated in each furnace. 
 The cylinders are perforated at bot- 
 tom, and stand en plates pierced with 
 corresponding apertures. Beneath these 
 plates, in the chambers c c, are placed 
 earthen pots p p, to receive the melted 
 sulphide. The process lasts three hours, 
 and when it is finished, the residues are 
 taken out, either through the top of 
 the furnace, or through apertures in the 
 lower part of the cylinders (which are 
 stopped with clay during the melting), 
 and then the cylinders are refilled. 
 With this arrangement, 64 pts. of coal are 
 consumed for every 100 pts. of crude 
 antimony produced. 
 
 Lastly, the ore is sometimes heated on 
 the hearth of a reverberatory furnace, without the use of either pots or cylinders. 
 The furnace has an inclined hearth, and the fused sulphide flows into a receiver 
 placed outside. This arrangement, which is in use at Linz, in Prussia, and at Eame 
 in La Vendee, effects a great saving of fuel, and likewise dues away with the expense 
 of the containing vessels ; but it involves a considerable loss of sulphide of antimony 
 by volatilisation, and is therefore adopted only where fuel is very dear. 
 
 Whatever arrangement may be adopted, it is important that the ore be not broken 
 into very small pieces. If it be too much divided or pulverised, the melted sulphide 
 cakes together with the gangue, and is very difficult to separate. Too great heat must 
 also be avoided, as at a white heat, sulphide of antimony is perfectly volatile. The 
 residues always contain 10 or 12 per cent, of antimony, partly as sulphide, partly as 
 
330 ANTIMONY: TRISULPHIDE. 
 
 oxide. [For further details, see Bruno Karl's " Handbuch der metallurgischen 
 Hiittenkunde," Freiberg, 1858, iii. 25.] 
 
 Native sulphide of antimony crystallises in prisms belonging to the trimetric system, 
 with four-sided summits resting on the lateral faces. Cleavage very distinct, parallel 
 to the shorter diagonal and the principal axis. Specific gravity 4-516 (Haiiy) ; 4*62 
 (Mohr). Hardness = 2. It is sectile, and in thin laminae slightly flexible; fracture 
 subconchoi'dal. It has a metallic lustre and lead-grey colour, inclining to steel-grey, 
 sometimes iridescent. Produces a streak of the same colour. The fused sulphide 
 generally forms blackish -grey, radiating, specular masses, having a steel-grey lustre. 
 It is easily fusible, thin splinters melting even in the flame of a candle. 
 
 The native sulphide is seldom pure, being generally contaminated with lead, copper, 
 iron and arsenic. "Wittstein found in four samples of crude antimony : 
 
 Antimony 62-48 59-67 7C) C; 26 71'98 
 
 Lead 
 Iron 
 Arsenic 
 Sulphur 
 
 10-40 11-96 
 0-70 0-63 0-31 
 
 trace trace 
 
 26-42 27-74 29-43 28-02 
 
 100-00 100-00 100-00 100-00 
 
 a. Iridescent, from Kronach in Upper Franconia ; b. Non-iridescent, from the same 
 locality ; c. Hungarian ; d. English. 
 
 The best way of detecting these impurities is to heat the finely pulverised mineral 
 with strong hydrochloric acid, till it is completely decomposed. Lead, if present in 
 any considerable quantity, will then separate on cooling, as crystallised chloride ; water 
 added to the solution will throw down oxychloride of antimony, while iron, copper, 
 arsenic, and a little lead will remain in solution ; copper may then be detected by 
 ammonia, iron by ferrocyanide of potassium, lead by sulphuric acid. 
 
 To detect arsenic, the pulverised mineral is deflagrated with nitrate and carbonate 
 of sodium ; the fused mass boiled with water, the filtrate acidulated with hydrochloric 
 acid, and sulphurous acid added to reduce the arsenic acid to arsenious acid, which 
 may then be precipitated by sulphuretted hydrogen. The precipitate, however, may 
 likewise contain sulphide of antimony, and must therefore be further examined. 
 
 To obtain pure crystallised trisulphide of antimony, it is best to prepare it arti- 
 ficially, by fusing pure metallic antimony with sulphur. 13 pts. of finely pulverised 
 antimony are mixed as intimately as possible with 5 pts. of flowers of sulphur, and the 
 mixture is thrown by small portions into a heated crucible, care being taken not to 
 add a fresh portion till the combination of the last portion is completed, which may 
 be known by the incandescence which accompanies the action. When the whole has 
 been added, the crucible is covered and left to cool. If any portion of the antimony 
 remains uncombined, it will sink to the bottom of the fused mass, and may easily be 
 separated from the sulphide after cooling. It is sometimes recommended to remelt 
 the product two or three times with smaller quantities of sulphur. 
 
 The reactions of crystallised sulphide of antimony are the same as those of the 
 amorphous sulphide, to be presently described : but they take place less quickly, on 
 account of the greater cohesion of the mass. 
 
 Amorphous Trisulphide of Antimony, Mineral Kermes. Brown-red sulphide 
 of Antimony, Pulvis Carthusianorum, Sulphur stibiatum rubrum, Stibium sulphur atum 
 rubrum. This substance is prepared by a great variety of processes, some of which 
 yield the pure trisulphide, differing from the native compound only in colour and in 
 the absence of crystalline structure, while others yield the sulphide more or less mixed 
 with the trioxide, and sometimes with other antimonial compounds. 
 
 a. The pure amorphous sulphide may be obtained by the following processes. 
 1. By keeping the grey trisulphide in the fused state for a considerable time, and then 
 cooling it very suddenly by throwing the vessel in which it has been melted into a 
 large quantity of cold water (Fuchs). 2. By dissolving the native sulphide in potash- 
 ley, and precipitating by an acid (Liebig). 3. By igniting 1 pt. of crude antimony with 
 2 pts. of black flax (a mixture of 1 pt. nitre, and 2 pts. cream of tartar), boiling the 
 ignited mass with water, and mixing the clear filtrate with an alkaline carbonate, 
 whereby the pure amorphous sulphide is precipitated (Liebig). 4. By the decom- 
 position of alkaline sulphantimonites (livers of antimony). 5. By treating mineral 
 kermes containing oxide of antimony, with tartaric acid, whereby the oxide is 
 dissolved out. 
 
 b. Mineral Kermes containing oxide is obtained by the action of alkalis on the tri- 
 sulphide. The oldest method, given by La Ligerie, consists in boiling the finely 
 pulverised grey sulphide with the solution of an alkaline carbonate, and leaving the 
 
ANTIMONY: TRISULPIIIDE. 331 
 
 filtered solution to cool : the same process is given in the last edition of the Prussian 
 Pharmacopoeia. As however, crystallised sulphide of antimony dissolves but slowly in 
 alkaline carbonate, it is better first to convert the crystallised into the amorphous 
 sulphide, and prepare the kermes from the latter. The following is the process given 
 by Lie big (Handw. d. Chem. 2 te Aufl. ii. 121). 
 
 1 pt. of the pulverised grey sulphide is boiled for an hour with 1 part of solid 
 caustic potash and 30 pts of water (or 1 pt. of the grey sulphide with 4 pts. potash-ley 
 of specific gravity 2'25 and 12 pts. water, or 1 pt. sulphide, with 1 pt. carbonate of 
 potassium, 1^ pts. slaked lime, and 15 pts. water), and the filtered liquid is mixed 
 with dilute sulphuric acid, whereby amorphous sulphide of antimony is precipitated. 
 The thickish mixture is then divided into three parts, and covered with water in three 
 separate vessels ; the precipitate is left to settle ; the water is decanted ; and fresh 
 water added till the precipitates are well washed : they are then placed upon three 
 separate filters. 1 pt. of anhydrous (or 27 pts. of crystallised) carbonate of sodium is 
 next dissolved in 34 pts. of water ; the precipitate from the first of the three filters is 
 introduced into the filtered solution ; the liquid is boiled for an hour ; and the solution, 
 which has taken up all the sulphide of antimony, is left to cool, whereupon it deposits 
 kermes. The supernatant liquid is now brought to the boiling heat, the second pre- 
 cipitate is added to it and treated in the same manner, and finally the same 
 processes are repeated with the third. The finest coloured kermes is deposited from 
 the second boiling. The precipitates are washed with cold water : their weight after 
 drying, amounts to nearly the half of the grey sulphide used. [For the rationale of the 
 process, see DECOMPOSITIONS OF SULPHIDE OF ANTIMONY, p. 333.] 
 
 The solution obtained by boiling the grey sulphide with caustic potash or soda 
 deposits kermes on cooling, provided the alkali is not in great excess ; and by boiling 
 the mother-liquors remaining after the deposition of the kermes with the undissolved 
 portion of the grey sulphide, fresh deposits, smaller in quantity, may be obtained. 
 According to Duflos, the solution obtained by boiling 100 pts. of grey sulphide for 
 a quarter of an hour whh a solution of 30 parts of hydrate of potassium in 300 pts. 
 of water, deposits on cooling 25 pts. of kermes ; a second boiling of the mother-liquor 
 with the undecomposed grey sulphide yields 10 pts.; a third yields 2'3 pts. The 
 successive deposits thus formed are continually richer in oxide of antimony. 
 
 A solution containing so much alkali as not to yield any deposit on cooling, yields 
 a precipitate of kermes when carbonic acid gas is passed through it, and afterwards 
 an additional quantity when treated with strong acids. The precipitate thus formed 
 generally contains a little oxide, and always a sulphantimonate of potassium or sodium, 
 of the form K 2 S.Sb 2 S 5 , because, according to H. Kose, part of the antimony is oxidised 
 by the air, and gives up its sulphur to the trisulphide of antimony, thereby converting 
 it into pentasulphide. 
 
 Kermes may likewise be obtained by boiling sulphide of antimony with potash-ley 
 and sulphur, or by boiling a solution of sulphantimonite of sodium with metallic anti- 
 mony. There are also several other modes of preparation, for which we must refer to 
 Gmelin's Handbook, vol. iv. pp. 340349, where they are fully described. The pre- 
 parations obtained by these different methods, are, however, by no means identical ; 
 they contain variable proportions of oxide of antimony, and many of them likewise 
 contain sulphantimonite of potassium or sodium. 
 
 Properties. The pure amorphous trisulphide obtained by Euchs's method is a dense 
 fissured mass, harder than the native sulphide, having a conchoi'dal fracture, a grey 
 colour, or in thin pieces, dark hyacinth-red, and yielding a red-brown powder some- 
 what lighter in colour than ordinary kermes ; its specific gravity is 4' 15. The pure 
 amorphous sulphide prepared by other methods is a brown-red, loosely coherent 
 powder, which makes a brown streak on paper. It is lighter than the native sulphide, 
 and does not conduct electricity. It contains water, which it gives off below 100 C. 
 When treated for some time with cold hydrochloric acid, or when fused and very 
 slowly cooled, it is converted into the crystalline sulphide. 
 
 Ordinary kermes containing oxide is a brown-red loose powder, which becomes 
 blackish-grey when washed with boiling water. By fusion and slow cooling, it is con- 
 verted into a slag-like mass, totally destitute of crystalline structure, a property by 
 which it differs essetnially from the pure amorphous sulphide. 
 
 Hydrated Trisulphide of Antimony. The amorphous sulphide is obtained as a 
 hydrate by passing sulphuretted hydrogen through an acid solution of the trichloride, 
 or through a solution of tartar-emetic acidulated with acetic acid. The precipitate at 
 first formed in a solution of the trichloride acidulated with tartaric acid, is a mixture of 
 the hydrated sulphide with oxychloride ; but on continuing the passage of the gas, it be- 
 comes darker in colour, and is completely converted into the hydrated sulphide. The 
 precipitate obtained by decomposing a solution of sulphantimo'nate of potassium with 
 sulphuric acid is probably also the hydrated sulphide. 
 
332 ANTIMONY: TRISULPHIDE. 
 
 Hydrated trisulphide of antimony when dry has a fine dark orange-colour. It gives off 
 water when moderately heated, but to dehydrate it completely, requires a temperature 
 of 200 C. it then turns black. At higher temperatures, it melts and solidifies in the 
 crystalline form on cooling. 
 
 Decompositions of Trisulphide of Antimony. The reactions of this compound are 
 nearly the same, whether it be in the crystalline or in the amorphous state, the crystalline 
 variety merely acting less quickly on account of its closer state of aggregation. 
 1. The dry amorphous sulphide touched with a red-hot body burns away in the air with 
 a glimmering light, producing sulphurous anhydride, antimonious oxide, and antimonic 
 oxide ; the grey sulphide heated above its melting point, burns with a blue flame, 
 yielding the same products. 2. The recently precipitated amorphous sulphide is de- 
 composed by boiling for some time with a large quantity of water, yielding hydro- 
 sulphuric acid and antimonious oxide, which dissolve. Vapour of water passed over 
 red-hot sulphide of antimony likewise yields hydrosulphuric acid and antimonious 
 oxide, the latter combining with undecomposed sulphide, and an orange-yellow body 
 subliming. 
 
 3. Chlorine, with the aid of heat, decomposes the trisulphide completely, forming 
 trichloride of antimony and chloride of sulphur. 4. Heated in hydrochloric acid gas 
 or boiled with the strong aqueous acid, it gives off hydrosulphuric acid, and forms 
 trichloride of antimony, which in the latter case dissolves in the excess of acid. 
 6. With strong sulphuric acid, it yields sulphurous anhydride and antimonious sulphate, 
 the sulphur being separated as a compact mass. 6. With strong nitric acid, it forms 
 antimonious oxide and sulphuric acid, part of the sulphur, however, being set free and 
 remaining mixed with the oxide. 7. Aqua-rcgia containing excess of hydrochloric 
 acid dissolves the trisulphide, forming trichloride of antimony and sulphuric acid, 
 and leaving a residue of sulphur often mixed with a little antimonic acid. 8. The 
 trisulphide ignited with nitrate of potassium or sodium, is violently oxidised, being 
 completely converted into sulphuric and antimonic acids, if 17 pts. or more of nitre 
 are used to 10 of antimony ; with less nitre, a compound of sulphide of potassium, 
 sulphide of antimony and antimonic oxide is likewise formed. 9. Many metals, e. g. 
 iron, potassium, and sodium (or a mixture of carbonate of potassium or sodium with 
 charcoal), decompose sulphide of antimony at a red heat, the resulting metallic sulphide 
 sometimes uniting with undecomposed sulphide of antimony; if, on the other hand, the 
 reducing metal is in excess, it sometimes forms an alloy with the reduced antimony. 
 
 10. The fixed caustic alkalis decompose trisulphide of antimony in the same manner 
 in the wet and in the dry way, forming trioxide of antimony and a sulphide of the 
 alkali-metal : 
 
 3K 2 = 3K 2 S + Sb 2 3 , 
 
 but the final products of the action vary according to the state of aggregation of the 
 antimonious sulphide, the temperature to which the mixture is exposed, and the pro- 
 portions of the two substances present, a. When amorphous sulphide of antimony, 
 prepared in the wet way, is triturated with cold potash-ley, it dissolves completely up 
 to a certain point, the sulphide of potassium formed as above, taking up undecomposed 
 sulphide of antimony, and the antimonious oxide dissolving in the potash. This 
 solution contains sulphantimonite and antimonite of potassium. When treated with 
 acids, it yields a precipitate of antimonious sulphide, without evolution of sulphuretted 
 hydrogen, because the quantity of that compound evolved by the decomposition of the 
 sulphide of potassium present, is but just sufficient to convert the trioxide of antimony 
 into trisulphide. But if the addition of the trisulphide be continued, a point is at 
 length reached, at which the alkaline liquid cannot take up any more antimonite of 
 potassium, and any further quantity of antimonious oxide then formed remains undis- 
 solved, partly combined with potash, partly with antimonious sulphide, forming the 
 mixture called crocus antimonii (328). The incomplete solution thus formed contains, 
 however, a larger proportion of sulphide of potassium than the complete solution, the 
 excess being proportional to the quantity of oxide left undissolved. This excess of 
 sulphide of potassium takes up an additional quantity of sulphide of antimony, and 
 the solution treated with acids, evolves sulphuretted hydrogen, besides giving a pre- 
 cipitate of antimonious sulphide. The complete solution mixed with carbonate of 
 ammonium, or with acid carbonate of potassium or sodium, yields a dirty brown pre- 
 cipitate consisting of 3 at. antimonious sulphide with 1 at. sulphide of potassium or 
 sodium, a portion of the alkaline sulphide also remaining in the liquid. The greater 
 part of the ^ alkaline antimonite is likewise precipitated, because the caustic alkali 
 which held it in solution is converted into neutral carbonate. The precipitation of 
 the antimonious oxide, is, however, partly caused by its affinity for the sulphide 
 of antimony previously thrown down in combination with the alkali-metal. The 
 incomplete solution is decomposed in like manner, but the precipitate contains a 
 
ANTIMONY: TRISULPHIDE. 333 
 
 smaller proportion of antimonic oxide. The complete solution rapidly absorbs oxygen 
 from the air ; the sulphide of potassium is first decomposed, yielding oxide of potas- 
 sium and sulphur, which then converts the trisulphide of antimony into penta- 
 sulphide : 
 
 3K 2 S + Sb 2 S 3 + O 2 = 2K 2 + K 2 S.Sb*S 5 
 
 so that the solution treated with acids yields a precipitate of pentasulphide of anti- 
 mony ; and subsequently the antimonite of potassium is converted into antimonate, 
 which collects in crystals at the bottom. 
 
 b. When antimonious sulphide in excess is digested with hot caustic alkalis, the 
 products formed are the same as in the cold, excepting that the sulphide of potassium 
 then takes up a larger proportion of antimonious sulphide, the excess of which is sub- 
 sequently deposited on cooling ; not, however, in the pure state, but in combination, 
 partly with alkaline sulphide, partly with antimonious oxide, the composition of the 
 precipitate being, in fact, similar to that which is produced by alkaline bicarbonates 
 in a cold-prepared solution of antimonious sulphide. The supernatant liquid gives 
 with alkaline bicarbonates a precipitate of alkaline sulphantimonite free from oxide. 
 
 All the precipitates above-mentioned are altered in composition by prolonged treat- 
 ment with cold water containing air, or with boiling water, antimonious oxide being 
 dissolved out, in combination with alkali, and pure dark-coloured antimonious sulphide 
 remaining. 
 
 c. Crystalline antimonious sulphide is acted upon by caustic alkalis in the same way 
 as the amorphous sulphide, but less easily, and when the action takes place in the 
 cold, a residue of crocus antimonii is always left, whatever may be the quantity of 
 alkali present. The resulting solution exhibits the reactions of the incomplete solution 
 above-mentioned. 
 
 11. Alkaline carbonates, fused with antimonious sulphide, either crystalline or 
 amorphous, give off carbonic anhydride, and form antimonious oxide and a sulphide of 
 the alkali-metal, the fused mass containing these products in combination with excess 
 of antimonious sulphide and alkali. With 4 pts. antimonious sulphide and 1 pt. 
 alkaline carbonate, an easily fusible mass is formed, which, after cooling, has an iron- 
 grey colour, is perfectly homogeneous, and is not attacked by water. A mixture of 
 2 pts. carbonate to 1 pt. antimonious sulphide requires a strong red heat to melt it, 
 and yields on cooling 12 per cent, of metallic antimony, together with a light brown 
 liver of antimony, which deliquesces in the air, and is perfectly soluble in water. The 
 separation of the metallic antimony results from decomposition of the alkaline anti- 
 monite contained in the mass, part of it being converted into antimonate. With 
 intermediate proportions, the mixture fuses more readily, and the resulting liver of 
 antimony is less soluble in water as the proportion of antimonious sulphide is greater. 
 The insoluble residue contains the excess of antimonious sulphide in combination with 
 a portion of the alkaline sulphide and with antimonious oxide ; it is, in fact, similar in 
 composition to the crocus prepared in the wet way, but generally contains more sulphide 
 of antimony. Water acts upon these livers of antimony exactly in the same manner 
 as solutions of the caustic alkalis act upon antimonious sulphide under the same 
 circumstances. 
 
 Solutions of alkaline carbonates do not act on antimonious sulphide in the cold, but 
 at the boiling heat, they dissolve the amorphous sulphide readily, the crystalline 
 slowly. The hot solution, prepared out of contact with the air, contains the same 
 
 Products as the complete solution of the amorphous sulphide in cold potash-ley (p. 332). 
 t becomes turbid on cooling, and deposits a grey -brown precipitate similar in compo- 
 sition to that which is produced by alkaline bicarbonates in the cold complete solution 
 just mentioned, consisting, in fact, of two compounds, viz. an alkaline sulphantimonite 
 and an oxysulphide of antimony. The liquid, after the separation of this precipitate, 
 retains a certain portion of alkaline sulphide. 
 
 If the solution of antimonious sulphide in hot alkaline carbonate be boiled for some 
 time in contact with the air, part of the alkaline sulphide becomes oxidised, and gives 
 up part of its sulphur to the dissolved trisulphide of antimony, thereby converting it 
 into pentasulphide, which remains in solution after cooling. The quantity of anti- 
 monious oxide in the precipitate remains the same, but the proportion of antimonious 
 sulphide in it is diminished by the quantity thus retained in solution. The proportion 
 of sulphide of sodium is likewise diminished by the oxidation. The quantity of 
 antimonious oxide in the precipitate is now not only sufficient to replace all the 
 alkaline sulphide in combination with the precipitated antimonious sulphide, but a 
 certain quantity of alkaline antimonite likewise remains free in the liquid ; and there 
 is precipitated a compound of trioxide and trisulphide of antimony, which is the true 
 medicinal kermes ; it is generally, however, mixed with small quantities of alkaline 
 antimonite. 
 
334 ANTIMONY: SULPHANTIMONITES. 
 
 Kermes prepared in this manner, contains, under all circumstances, -a tolerably 
 constant quantity of antimonious oxide, because, when alkaline carbonates are used, 
 the portion of sulphide of antimony attacked by them passes completely into the solution, 
 without leaving any residue, and consequently the entire quantity of the products thus 
 formed is likewise contained in the liquid. (Lie big, Handwort. d. Chem. 2 te . Aufl. ii. 
 125130.) 
 
 12. By ignition with baryta, strontia, lime, and other oxides, antimonious sulphide is 
 decomposed in the same manner as by caustic and carbonated alkalis : the products 
 are insoluble in water, and consist of mixtures of metallic sulphantimonites with an 
 oxysulphide of antimony. 
 
 SITLPHA.NTIMONITES. Trisulphide of antimony is a sulphur-acid, uniting with basic 
 metallic sulphides. Some of these compounds, containing the sulphides of the heavy 
 metals, are natural minerals, viz. : 
 
 Zinkenite Pb 2 S . Sb 2 S 3 
 
 Miargyrite Ag 2 S . Sb 2 S 3 
 
 Antimonial Copper-glance .... Cu'S . Sb 2 S 3 
 
 Plagionite 4Pb 2 S . 3Sb 2 S 3 
 
 Jamesonite . . . . . 3Pb 2 S . 2Sb 2 S 3 
 
 Feather-ore 2Pb 2 S . Sb 2 S 3 
 
 Boulangerite . 3Pb 2 S . Sb 2 S 3 
 
 Pyrargyrite 3Ag 2 S . A ^|s 3 
 
 Bournonite .... 3(Cu 4 S.Sb 2 S 3 ) + 3Pb 2 S.2Sb 2 S 3 ) 
 
 (25) 
 
 Stephanite 6Ag 2 S . Sb 2 S 3 
 
 (25) 
 
 Berthierite 3Fe 2 S . 2Sb 2 S 3 
 
 Variety of Berthierite, from Anglar . . Fe^ . Sb 2 S 3 
 Variety of Berthierite, from Marturet . . 3Fe a S . 4Sb 2 S 3 
 
 In these formulae, the elements whose symbols are written one above the other, 
 replace one another isomorphously. [For description, see the names of the several 
 minerals.] 
 
 The most important of the artifically prepared sulphantimonites are those which 
 contain the protosulphides of the alkali- metals : they are called LiversofAntimony 
 (Hcpar Antimonii'). They are obtained, mixed with oxide in various proportions, by 
 fusing the trisulphide of antimony with alkaline carbonates, or metallic antimony with 
 sulphate of potassium ; and free from oxide, by melting sulphide of antimony with 
 alkaline sulphates and charcoal, or with alkaline carbonates, sulphur and charcoal, or 
 again by melting sulphantimonate of sodium with metallic antimony. 
 
 These alkaline sulphantimonites, or livers of antimony, are easily fusible, and deli- 
 quescent or unalterable in the air, according to the proportion of the alkaline sulphide 
 and the antimonious sulphide contained in them. They are more or less soluble in 
 water, when the ratio of the antimonious sulphide to the alkaline sulphide is less 
 than 2:1; insoluble, when it is greater. 
 
 In the fused state, they are black or black-brown and crystalline. Their solutions 
 boiled with pulverised antimonious sulphides, dissolve an additional quantity of it, 
 which on cooling is deposited as a flocculent precipitate containing also the alkaline 
 sulphide. Acids added to the solutions throw down the amorphous sulphide; so like- 
 wise does carbonate of ammonium. Alkaline bicarbonates immediately throw down 
 sulphantimonite of potassium or sodium ; the solution mixed with an alkaline mono- 
 carbonate, remains clear at first, but solidifies after a while to a tremulous jelly con- 
 taining the same compound. The same effect is produced when the aqueous solution 
 of a liver of antimony is diluted with a large quantity of cold water. The solution of 
 a liver of antimony changes very quickly when exposed to the air, a sulphantimonate 
 being formed in solution, and a portion of the trisulphide of antimony being separated 
 in brown metallic films or as a powder. 
 
 PENTASTTLPHIIXE OF ANTIMONY; ANTIMONIC SULPHTDE ; ANHYDROUS SULPHAN- 
 TIMONIC Aero. Persulphide of Antimony ; Golden Sulphuret of Antimony; Sulphur 
 Antimonii auratum, Sb 2 S 5 , or SbS*. This compound is not found native. It is pre- 
 pared : 1. Bypassing sulphuretted hydrogen through a mixture of the pentachloride 
 with water and tartaric acid, or through antimonic oxide suspended in water. 2. By 
 decomposing the solution of the sulphantimonate of an alkali-metal with an acid, the 
 sodium-salt, for example, whereby the sulphide of sodium is decomposed, a salt 
 
ANTIMONY: SULPHANTIMONATES. 335 
 
 of the alkali metal being formed, with evolution of sulphuretted hydrogen, and penta- 
 sulphide is precipitated : 
 
 3Na 2 S.Sb 2 S 5 + 6HC1 = GNaCl + 3H 2 S + Sb 2 S 5 . 
 
 Sulphantimonate 
 of sodium. 
 
 [For details see Gmelin's Handbook, iv. 355 ; Handworterb. d. Chem. 2* Aufl. ii. 
 133.] 
 
 Pentasulphide of antimony is a yellowish-red powder, or loosely agglomerated mass, 
 without any trace of crystalline structure ; it has a very feeble odour of sulphur, a 
 sweetish sulphurous taste, and is slightly emetic. Heated in close vessels to the boil- 
 ing point of sulphur, it is resolved into the trisulphicle and free sulphur. It burns 
 with flame when heated in the air. Exposed to the air in the moist state, it is partly 
 converted, after a while, into the trioxide of antimony. Hot hydrochloric acid decom- 
 poses it, giving off sulphuretted hydrogen, separating sulphur, and forming an aqueous 
 solution of trichloride of antimony; cold hydrochloric acid imparts to it a greyish 
 colour, perhaps in consequence of the formation of the trisulphide and liberation of 
 2 at. sulphur. Triturated, out of contact of air, with aqueous ammonia, it dissolves 
 completely, more easily in a warm acid than in a cold solution, and is precipitated 
 therefrom by acids. If the pentasulphicle contains trisulphide, the latter remains as 
 a brown residue ; a yellow or white residue, on the otaer hand, indicates the presence 
 of sulphur or of antimonic oxide. The pentasulphide dissolves readily in potash or 
 soda-ley, also in sulphide of ammonium. "With a solution of sulphate of copper or 
 nitrate of silver, it forms Sulphantimonate of copper or silver, together with antimonic 
 oxide. 
 
 SULPHANTIMONATES. Pentasulphide of antimony is a strong sulphur-acid, uniting 
 readily with the more basic metallic sulphides, and forming sulphur-salts, most of 
 which have the composition 3M v S.Sb 2 S 5 , or M 3 SbS 4 [or SMS.SbS 5 , if 8 = 16], analo- 
 gous to that of the ordinary tribasic phosphates (M 3 P0 4 ). The sulphantimonates of 
 the alkali-metals and alkaline earth-metals, are very soluble in water, and crystallise 
 for the most part with several atoms of water ; none of them appear to be soluble in 
 alcohol. The sulphantimonates of the heavy metals are insoluble in water. 
 
 The soluble sulphantimonates are obtained : 1. By fusing pentasulphide of antimony 
 or a mixture of the trisulphide and sulphur, with the sulphide of an alkali-metal, or 
 with charcoal and the carbonate or sulphate of an alkali-metal. If a strong heat is 
 used, the addition of sulphur to the trisulphide is unnecessary, as at high temperatures 
 that compound is resolved into metallic antimony and the pentasulphide. 2. By dis- 
 solving pentasulphide of antimony in aqueous solutions of the alkaline hydrosulphatcs. 
 3. By dissolving the pentasulphide in the solution of a caustic alkali, or of an alkaline 
 carbonate at the boiling heat ; in which process an antimonate of the alkali-metal 
 is formed simultaneously, and deposited as a white powder. 4. By decomposing the 
 aqueous solutions of the alkaline antimonates with hydrosulphuric acid, f of the anti- 
 mony being thereby separated as pentasulphide, because the alkaline antimonates are 
 monobasic, and the sulphantimonates tribasic : 
 
 3(K*O.Sb 2 5 ) + 18H 2 S = 3K 2 S.Sb-S 5 + ISIP + 2Sb 2 S 5 . 
 or : SKSbO 3 + 9H 2 S = K 3 SbS 4 + 9H 2 + Sb 2 S 5 . 
 
 The insoluble sulphantimonates are prepared by gradually adding a solution of a 
 metallic salt to a solution of the Sulphantimonate of an alkali-metal, that of sodium 
 being generally used, keeping the latter in excess. If, on the other hand, the solution 
 of the other salt is in excess, and especially if the liquid be boiled, the resulting pre- 
 cipitate contains oxygen, and the liquid is found to contain free acid. The precipitates 
 thus formed generally contain 3M 2 S.Sb-S 5 + 5M 2 0, or rather 8M 2 S + Sb 2 5 , being, in 
 fact, mere mixtures of a metallic sulphide with autimonic oxide, the latter being 
 retained in them by its insolubility. (Rammelsberg, Pogg. Ann. lii. 193.) 
 
 The soluble sulphantimonates are decomposed by all acids, even by carbonic acid, 
 with evolution of sulphuretted hydrogen. Many of the insoluble salts are decomposed 
 only by nitric acid and aqua-regia, The sulphantimonates of the alkali-metals are not 
 decomposed by ignition in closed vessels ; those of the heavy metals give off sulphur 
 at a red heat, leaving sulphantimonites containing 3M 2 S.Sb 2 S 3 , or M 3 SbS 3 . 
 
 Sulphantimonate of Ammonium, 3(NH 4 ) 2 S.Sb 2 S 5 , or (NH 4 ) 3 SbS 4 , is produced 
 by digesting pentasulphide of antimony in excess with pure sulphide of ammonium, 
 free from excess of ammonia. It cannot be obtained in the solid state, being decom- 
 posed both by concentration, even out of contact with the air, and by mixture with 
 alcohol. 
 
 Sulphantimonate of Barium, Ba'SbS 4 + 3H 2 0. Obtained by dissolving re- 
 
336 ANTIMONY: SULPHANT1MONATES. 
 
 cently precipitated prosulphide of antimony in sulphide of barium, and mixing the 
 solution with alcohol, in stellate needles, which, when exposed to the air, do not 
 deliquesce, but become covered with a brown kermes-coloured film. 
 
 Sulphantimonate of Bismuth is obtained by precipitation, but is not easily 
 obtained free from excess either of pentasulphide of antimony or of sulphide of bismuth. 
 
 Sulphantimonate of Cadmium. Light orange-coloured precipitate obtained by 
 dropping a neutral cadmium-salt into a solution of Sulphantimonate of sodium. 
 
 Sulphantimonate of Calcium. Sulpho stibias-calcius. Ca s SbS 4 . Produced 
 like the barium-salt, but cannot be crystallised. A mixture of this compound with 
 excess of lime and saffron of antimony, constitutes the pharmaceutical preparation 
 known as Calx antimonii cum sufphure Hoffmanni, Sulphurctum stibii cum calce, 01 
 Calcaria sulphurata stibiata, discovered by Hoffmann in the eighteenth century. L 
 is prepared by igniting an intimate mixture of 3 pts. trisulphide of antimony, 4 pts. 
 sulphur, and 16 pts. quicklime ; or 8 pts. of prepared oyster shells, 1 pt. antimony, 
 and 2 pts. sulphur. It is a whitish-yellow, yellowish, or brownish-yellow powder, whieh 
 has a sharp sulphurous taste, smells of sulphuretted hydrogen when exposed to mois? 
 air, and is but partially soluble in water. The solution is colourless, and contain 
 Sulphantimonate of calcium. 
 
 Sulphantimonate of Cobalt, obtained by precipitation, is black, oxidises in the 
 air, and is decomposed by boiling hydrochloric acid. 
 
 Sulphantimonate of Copper. Cu 3 SbS 4 . Obtained by dropping a solution of 
 cupric acetate or sulphate into a solution of Sulphantimonate of sodium. The solutions 
 must be rather dilute ; the copper-solution must be dropped in slowly and with rapid 
 stirring ; and the precipitate then heated, together with the liquid, with brisk stirring 
 all the while. "Without these precautions, each drop of the copper-solution, as it 
 enters, becomes enveloped by the precipitate ; and if the precipitate be thrown on the 
 filter in this state, the solution of Sulphantimonate of sodium runs away first, and then 
 the acetate of copper and Sulphantimonate of copper decompose each other, acetic acid 
 or sulphuric acid being set free, which then acts upon the Sulphantimonate of sodium 
 still remaining in the precipitate, setting free pentasulphide of antimony and hydro- 
 sulphuric acid. In this manner, the precipitate becomes contaminated with pentasul- 
 phide of antimony and sulphide of copper. Sulphantimonate of copper, when pure, is 
 a dark brown precipitate, which when heated gives off sulphur, and leaves a residue 
 apparently consisting of cuprous sulphantimonite (Sb' 2 S 3 with Cu 4 S). Boiling potash 
 decomposes the Sulphantimonate, separating sulphide of copper and dissolving penta- 
 sulphide of antimony, which is at the same time partially converted into antimonic 
 acid. 
 
 If Sulphantimonate of sodium be added to excess of cupric sulphate, and the pre- 
 cipitate boiled for some time with the liquid, a product is obtained containing 16 at. 
 copper, 8 at. sulphur, 2 at. antimony, and 5 at. oxygen, and the liquid exhibits a 
 strong acid reaction : 
 
 3Na 2 S.Sb 2 S 5 + 8Cu 2 S0 4 + 6H 2 = (8Cu 2 S + Sb 2 5 ) -t- 3Na 2 S0 4 + 5H 2 S0 4 . 
 
 The precipitate thus formed, may, as already observed (see above), be either 3Cu 2 S.Sb 2 S 5 
 + 5Cu 2 0, or 8Cu 2 S + Sb 2 5 . On boiling it with potash-ley, sulphide of copper 
 remains behind, and a solution of antimonate of potassium is formed, which gives with 
 acids a white precipitate of untimonic acid. On the other hand, the precipitate, when 
 quickly and strongly heated in close vessels, gives off a large quantity of sulphurous 
 anhydride, but no sulphur, and the residue contains sulphide of copper and pentasul- 
 phide of antimony. Moreover the same products are obtained by igniting a mixture 
 of 8 at. pure sulphide of copper, and 1 at. pure antimonic oxide, or of 1 at. Sulphantimo- 
 nate of copper and 5 at. cupric oxide. So far then it is impossible to decide upon the 
 constitution of the precipitate obtained in the manner just described. But when 
 sulpharsenate of potassium is dropt into excess of cupric sulphate, and the mixture 
 boiled, a precipitate is obtained consisting of pure sulphide of copper, the whole of 
 the arsenic remaining dissolved as arsenic acid. Hence, from the analogy of the 
 arsenic and antimony compounds, it is probable that the antimony precipitate above- 
 mentioned is a mixture of sulphide of copper and antimonic oxide. 
 
 Sulphantimonate of Iron. Ferrous sulphate dropt into Sulphantimonate of 
 sodium forms a black precipitate, which quickly turns reddish-yellow. The sodium-salt 
 forms with ammonio-ferric sulphate, so long as the latter is in excess, a greenish-brown 
 precipitate, consisting merely of sulphur and pentasulphide of antimony, the whole of 
 the iron being reduced to the ferrous state and remaining in the liquid. 
 
 Sulphantimonate of Lead. Pb 3 SbS 4 . Obtained by adding acetate of lead to 
 Sulphantimonate of sodium, with the same precautions as those described for the 
 
ANTIMONY: SULPHANTIMONATES. 337 
 
 preparation of the copper-salt. It is a dark brown precipitate, which is decomposer! 
 by heat, giving off 2 at. sulphur, and leaving sulphantimonite of lead, 31'b' 2 S.Sb-S*, or 
 Pb 3 SbS s , of the same composition as the mineral Boulangerite. Boiling potash-ley 
 decomposes it in the same manner as the copper-salt. A precipitate, containing 16Pb, 
 8S, 2Sb, and 5O, is likewise obtained by adding sulphantimonate of sodium to excess 
 of acetate of lead. 
 
 Sulphantimonate of Magnesium. Kecently precipitated pentasulphide of 
 antimony dissolves in aqueous hydrosulphuric acid, in which magnesia is suspended, 
 the magnesia likewise dissolving ; but the compound cannot be made to crystallise. 
 
 Sulphantimonate of Manganese. Eed-brown precipitate, produced by mix- 
 ing the sodium-salt with sulphate of manganese; it oxidises during washing and 
 drying. 
 
 Sulphantimonates of Mercury. The mercuric salt, 3Hg 2 S.Sb 2 S 5 , or Hg 3 SbS 4 , 
 obtained like the copper- and lead-salts, is an orange-coloured precipitate. If after 
 washing it be immersed in solution of mercuric chloride, or a solution of sulphanti- 
 monate of sodium be added to excess of mercuric chloride, a white substance is formed, 
 containing 3Hg 2 S.Sb' 2 S 5 + 6HgCl + 3Hg 2 0. This substance is not a mere mixture, 
 but a chemical compound, which is not attacked by any acid except aqua-regia. 
 Potash decomposes it immediately, leaving mercuric sulphide, and dissolving antimonic 
 and hydrochloric acids. Mercurous nitrate, mixed with sulphantimonate of sodium, 
 forms a black precipitate, whichever salt may be in excess. 
 
 Sulphantimonate of Nickel. Black precipitate, which oxidises in the air, and 
 is decomposed by hot hydrochloric acid. 
 
 Sulphantimonate of Potassium, K 3 SbS 4 ; in the crystallised state 2K 3 SbS 4 + 
 PH 2 0, or 3K 2 S.Sb 2 S 3 + 9H 2 0. The anhydrous salt is obtained by fusing sulphide of 
 potassium with trisulphide of antimony and sulphur, or sulphate of potassium with 
 the trisulphide and charcoal, or by heating one of the potassium-livers of antimony, 
 in which case metallic antimony separates out. The product is a brown mass, the 
 aqueous solution of which yields crystals of the hydrated salt. The latter is, however, 
 better obtained by boiling a mixture of 11 pts. of finely levigated trisulphide of anti- 
 mony, 6 pts. of carbonate of potassium, 1 pt. of flowers of sulphur, and 3 pts. of lime 
 previously burnt and slaked, with 20 pts. of water, for some hours, renewing the 
 water as it evaporates ; or by leaving the same mixture in a covered vessel for 24 
 hours, and stirring frequently ; then filtering and evaporating. The hydrated salt 
 forms colourless or yellowish, granular or radiating crystals, which give off their water 
 when heated. 
 
 Sulphantimonate of potassium is likewise formed when pentasulphide of antimony 
 is boiled with aqueous carbonate of potassium, antimonate of potassium being formed 
 at the same time, and separating in the solid state. Hot caustic potash-ley dissolves 
 the pentasulphide completely ; but on diluting the solution, and adding carbonate of 
 ammonium, a precipitate is formed, consisting merely of the pentasulphide mixed with 
 a small quantity of sulphantimonate of potassium. Cold potash-ley of moderate 
 strength acts upon pentasulphide of antimony somewhat differently ; the pentasulphide 
 loses its colour; white acid antimonate of potassium (K 2 0.2Sb 2 5 + 6H-0) remains 
 undissolved, notwithstanding the excess of potash present ; free sulphide of potassium 
 is formed ; and the liquid yields by evaporation a colourless double salt, consisting of 
 Rulphantimonate and antimonate of potassium (K 3 SbS 4 .KSb0 3 + 5H 2 0), crystallising 
 in long needles, which, when exposed to the air, become covered with a kermes- 
 coloured film. Cold water renders these crystals milk-white, dissolving a portion, and 
 leaving a white residue of acid antimonate of potassium. Hot water dissolves the salt 
 readily, and the solution, when mixed with acids, yields an orange-coloured precipitate, 
 consisting of pentasulphide of antimony mixed with antimonic acid. 
 
 Sulphantimonate of Silver, Ag 3 SbS 4 , prepared like the lead- and copper-salts 
 forms a black, perfectly insoluble precipitate, which gives off sulphur when heated, 
 leaving a fused grey residue of sulphantimonate of silver, Ag-^SbS 3 , which yields a red 
 powder by trituration. By adding sulphantimonite of sodium to excess of nitrate of 
 silver and boiling for several hours, a precipitate is obtained containing antimonic oxide, 
 which may be completely extracted from it by potash. 
 
 Sulphantimonate of Sodium, Na'SbS 4 + 9H 2 0, or ZNaS.SbS* + 9HO. 
 Schlippe's salt. This salt is prepared by digesting at ordinary temperatures in a 
 vessel that can be closed, and with frequent stirring, a mixture of 11 pts. of elutriated 
 trisulphide of antimony, 13 pts. crystallised carbonate of sodium, 1 pt. flowers of 
 sulphur, 5 pts. of quick lime previously slaked, and 20 pts. of water. After twenty-four 
 hours, the liquid is strained off, the residue washed several times with water and the 
 
 VOL. I. Z 
 
338 ANTIMONY: SULPHO-CHLORIDE. 
 
 solution together with the wash-water, is evaporated in a porcelain dish or clean iron 
 pot, till a sample yields crystals on cooling. The whole is then left to cool quietly, and 
 the resulting crystals are washed several times with cold water, and dried in the air, or 
 better, under a bell jar, over lime or oil of vitriol. The formation of the salt is much 
 accelerated by boiling the mixture. (Liebig, Handwort. d. Chem. 2 te Aufl. ii. 139. 
 For other modes of preparation, see Gmeliu's Handbook, iv. 384.) 
 
 Sulphantimonate of sodium forms transparent, colourless, or pale yellow, regular 
 tetrahedrons, with truncated summits, or acuminated with the faces of the rhombic 
 dodecahedron. Its taste is bitterly metallic, and at the same time alkaline. It dis- 
 solves in 2 '9 pts. of water at 15 C., and the solution is precipitated by alcohol. When 
 heated, it melts in its water of crystallisation, and after all the water has gone off, 
 forms a greyish-white mass, which crumbles to a bulky powder when exposed to the 
 air. At a commencing red heat, it fuses, without decomposition, if the air be excluded. 
 The fused mass is liver-coloured, and dissolves in water, leaving a small quantity of 
 sulphide of antimony. The decomposition of the solution, as well as of the salt itself, 
 by contact with the air, is due to the action of carbonic acid, btit is not complete even 
 after many months. The resulting brown precipitate contains sulphantimonate of 
 sodium with trisulphide of antimony, and the liquid is found to contain carbonate, 
 sulphide, and hyposulphite of sodium, but no sulphate. 
 
 When sulphantimonate of sodium is added to a solution of tartar-emetic, the liquid 
 first turns red, and then yields an orange-coloured precipitate containing pentasulphide, 
 trisulphide, and trioxide of antimony, while tartrate of sodium and potassium remains 
 in solution : 
 
 6C 4 H 4 KSb0 7 + 2Na 3 ShS 4 = 6C 4 H 4 KNa0 6 + Sb 2 S 5 + Sb'S 3 + 2Sb 2 3 
 
 This precipitate melts at a high temperature, forming a black metallic-shining mass, 
 exhibiting red translucence on the edges, and perfectly soluble in hydrochloric acid. 
 Potash decomposes it, leaving a yellow residue consisting of sulphide of sodium, tri- 
 oxide of antimony, and a compound of that oxide with potash. (Handworterbuch.) 
 
 Sulphantimonate of Strontium. -Prepared like the calcium-salt: not crys- 
 tallisable. 
 
 Sulphantimonate of Uraniu m. Yellow-brown precipitate, obtained by adding 
 ammonio-uranic chloride to sulphantimonate of sodium. 
 
 Sulphantimonate of Zinc, obtained by dropping sulphate of zinc into a solution 
 of the sodium-salt, is an orange-coloured precipitate which dissolves in the liquid when 
 heated, and partly runs through the filter during washing. It is decomposed and dis- 
 solved by hydrochloric acid. 
 
 The precipitate obtained with excess of the zinc-salt, has the same colour, but is not 
 easily obtained free from the preceding, even after long boiling. Fuming nitric acid 
 decomposes it, with ignition. (Handworterbuch.) 
 
 ANTIZVIOWS-, SUX.PHOCKX.ORXBE OP. SbSCl 3 . Obtained by slowly passing 
 dry sulphuretted hydrogen into pentachloride of antimony. It is a white crystalline 
 body, which melts at a moderate heat, is resolved at a higher temperature into sulphur 
 and trichloride of antimony, deliquesces in moist air, and is decomposed by water into 
 sulphur and trichloride (? oxychloride) of antimony ; with aqueous tartaric acid, it 
 yields a precipitate of sulphide of antimony mixed with oxide. (Cloez, Ann. Ch. 
 Phys. [3] xxx. 374.) 
 
 Other sulphochlorides of antimony have been obtained byE. Schneider (Pogg. 
 Ann. cviii. 407). Finely pulverised trisulphide of antimony dissolves in 14 or 15 
 times its weight of the melted trichloride, without evolution of sulphuretted hydrogen, 
 and the light brown solution solidifies on cooling to a yellow crystalline mass. By 
 pouring off the still remaining liquid at a certain stage of the solidification, the com- 
 pound may be obtained in regular crystals (rhombic prisms bevelled at the ends with 
 a macrodiagonal dome), containing Sb 2 SCl 4 .6SbCl 3 . It is very deliquescent, and is 
 decomposed by a large quantity of water, with separation of a yellow powder ; by 
 prolonged heating, it is resolved into volatile trichloride of antimony, and a black 
 residue of sulphide. It is decomposed by absolute alcohol, out of contact of air, a 
 large quantity of chloride of antimony and a little of the sulphide dissolving, and a 
 reddish-yellow amorphous substance being left, containing 28bClS.3Sb*S 3 . This com- 
 pound is decomposed, by heating in close vessels, into trichloride and trisulphide of 
 of antimony, also by the action of dilute hydrochloric acid. 
 
 A WTI1VIONY, SULPKIOUIDF, OP. SbSI. This compound is obtained by dis- 
 solving trisulphide of antimony in the melted tri-iodide. It has a brilliant metallic 
 lustre and red-brown colour, appears red and transparent under the microscope, and 
 yields a powder of a fine cherry-red colour. (R. Schneider, J.'pr. Chem. Izzix. 
 422; Rep. Chim. pure, ii. 323.) 
 
ANTIMONY-RADICLES (ORGANIC). 339 
 
 When a mixture of equal parts of iodine and trisulphide of antimony is slowly 
 heated in a retort, an iodosulphide, probably of the same composition, rises in red 
 vapours, which condense in the receiver. Tiie same body is formed by subliming a 
 mixture of 24 pts. antimony, 9 pts. sulphur, and 68 pts. iodine, or of 2 pts. iodine and 
 9 pts. iodide of sulphur, ft forms shining transparent, blood-red needles and laminae, 
 which melt at a gentle heat, and sublime more easily than the iodide of antimony. It 
 has a pungent taste and repulsive odour. It is decomposed at a strong heat, also by 
 chlorine and by water. Henry and Grarot (J. Pharm. x. 511), assigned to this pro- 
 duct the formula SbS s I 3 ; but this is doubtless incorrect. 
 
 ANTXAEONY'-RADXCXiES, ORGAX7XC. Antimony combines with alcohol- 
 radicles in various proportions, forming compounds which themselves act like simple 
 radicles, uniting with chlorine, oxygen, sulphur, &c., in the same manner as the 
 metals. Some of these bases are formed on the type of ammonia, NH 3 , containing 
 1 at. antimony.united with 3 at. of the alcohol-radicle ; others on the type NH 4 ; and a 
 compound of antimony with amyl is known containing 1 at. antimony with 2 at. amyl. 
 The names and formulae of the antimony-radicles at present known, are given in the 
 following table : 
 
 Antimonides of Amyl : 
 
 Stibdiamyl Sb(C s H") 2 
 
 Stibtriamyl or Triamylstibine .... Sb(C 5 H n ) 3 
 
 Antimonides of Ethyl : 
 
 Stibtriethyl or Triethylstibine .... Sb(C 2 H 5 ) 3 
 
 Stibethylium or Tetrethylstibonium . . . Sb(C 2 H 5 ) 4 
 
 Antimonides of Methyl : 
 
 Stibtrimethyl or Trimethylstibine . . . Sb(CH 3 ) 3 
 
 Stibmethylium or Tetramethylstibonium . . Sb^CH 3 ) 1 
 
 The existence of pentethylstibine Sb(C 2 H 5 ) 5 and pentamethylstibine Sb(CH 3 ) 5 , has 
 also been rendered probable by the recent experiments of Mr. Buck ton (Chem. Soc. 
 Qu. J. xiii. 115). 
 
 The compounds containing 3 at. of alcohol-radicle are obtained by distilling the iodides 
 of the alcohol-radicles with antimonide of potassium or sodium, or by the action of tri- 
 chloride of antimony on zinc-ethyl. They are liquids which volatilise without decom- 
 position, and rapidly absorb oxygen from the air, with great evolution of heat, sufficient 
 in the case of the ethyl- and methyl-compounds to produce vivid combustion. The 
 compounds containing 4 at. of alcohol-radicle are not known in the free state ; but 
 their iodides are obtained by treating the corresponding compounds containing 3 at. 
 alcohol-radicle with the iodides of those radicles ; and these iodides when treated 
 with oxide of silver and water, yield the hydrated oxides of the same radicles, which 
 are fixed bases, having a strong alkaline reaction, and uniting readily with acids like 
 the hydrates of potassium and sodium. In this respect, they resemble the correspond- 
 ing nitrogen-bases, hydrate of tetrethylium, N(C 2 H*) 4 .H.O, &c. 
 
 The antimony-radicles containing 4 at. of the alcohol-radicle, are monatomic, uniting 
 with 1 at. chlorine, iodine, &c. ; but those which contain 3 at. alcohol-radicle, stibtri- 
 ethyl, for example, are diatomic, uniting with 2 at. chlorine, iodine, &c., and with 1 at. 
 oxygen, e.g. Sb(C 2 H a ) 3 .Cl 2 , Sb(C 2 H 5 ) 3 O, &c. The same law holds good with respect 
 to other organo-metallic bodies similarly constituted, arsentriethyl, for example : but it 
 does not extend to the corresponding nitrogen-radicles, such as triethylamine, tri- 
 methylamine, &c., which, indeed, do not unite directly with oxygen, chlorine, iodine, 
 &c., but combine with hydrated acids in the same manner as ammonia. 
 
 Antimonides of A.myl, or Stibamyls.* 
 
 These compounds are obtained by the action of iodide of amyl on antimonide of 
 potassium, the process being conducted similarly to that for the preparation of stib- 
 ethyl (p. 341). After the action has ceased, and the excess of iodide of amyl has dis- 
 tilled off, the residue is either distilled in an atmosphere of carbonic anhydride, whereby 
 a distillate is obtained containing stibdiamyl; or the product is exhausted with ether, 
 and the solution freed from ether by distillation, in which case a residue is left con- 
 sisting of stibtriamyl. If the stibtriamyl thus obtained is contaminated with amylic 
 alcohol or iodide of amyl, pure compounds may be prepared from it by dissolving it in 
 a mixture of ether and alcohol ; adding alcoholic bromine till its colour just begins to 
 be permanent ; precipitating the bromide of stibtriamyl by adding a large quantity of 
 water; converting the bromide into oxide by means of oxide of silver suspended n 
 
 * F. Berle, J. pr. Chem. Ixv 385; Gm. xi. 125. 
 Z2 
 
340 ANTIMONY-KADICLES (ORGANIC). 
 
 alcohol ; precipitating the oxide by water, and dissolving it in hydrochloric acid and 
 alcohol ; precipitating the pure chloride by another addition of water ; and freeing it 
 from a small quantity of water by heating it to 100 C. in contact with fused chloride 
 of calcium. 
 
 STIBDIAMYL. Sb(C 5 H n ) 2 = SbAm 9 . The distillate just mentioned, after being 
 freed from undecomposed iodide of amyl by re-distillation over antimonide of potassium, 
 gave off at 80 C. a colourless liquid, which burnt with a white flame, diffusing a white 
 smoke of oxide of antimony. The liquid which then remained was stibdiamyl. It was 
 greenish-yellow, heavier than water, and tolerably mobile, with a peculiar aromatic 
 odour and bitter taste ; insoluble in water, but miscible in all proportions with alcohol 
 and ether. It was not spontaneously inflammable, but when set on fire, burned with 
 a very white flame, diffusing a white fume of oxide of antimony. It exploded with 
 great violence when heated in oxygen gas, and was decomposed by nitric acid with 
 considerable evolution of heat. Its ethereal solution exposed to the air, left an oxide 
 which absorbed carbonic acid; and the stibdiamyl itself heated to 100 C. in a 
 stream of dry carbonic acid, yielded a viscid liquid, which appeared to be the car- 
 bonate (SbAm 2 ) 2 .C0 8 . The haloid salts of stibdiamyl are gummy liquids; the 
 sulphate and nitrate are precipitated from their alcoholic solutions by water, in the 
 form of gummy masses, which dry up to amorphous solids. 
 
 STIBTRIAMYL or TRIAMYLSTIBINE. Sb(C 5 H") 3 = SbAm 3 . Transparent slightly 
 yellowish liquid, very viscid below 20 C., more mobile at higher temperatures. It has 
 a peculiar aromatic odour, and a bitter, somewhat metallic and very persistent taste. 
 Specific gravity 1'333 at 17 C. (according to Cramer, Pharm. Centr. 1855, 465, it is 
 1-0587). In contact with the air, it does not take fire, but fumes strongly and decom- 
 poses, depositing a white powder. A drop of it placed on bibulous paper and exposed 
 to the air, becomes so strongly heated as to char the paper. It is insoluble in water, 
 but dissolves sparingly in alcohol, and readily in ether. It does not exhibit any 
 tendency to unite with iodide of amyl, when heated with that compound in a sealed 
 tube. 
 
 Stibtriamyl is a diatomic radicle, like stibtriethyl. Its oxide, Sb(C 5 H n ) s .O = is pro- 
 duced by slow evaporation of an ethereal solution of stibtriamyl in contact with the air ; 
 or by decomposing the chloride, iodide, or bromide with oxide of silver. It is a greyish- 
 yellow viscid mass, which becomes somewhat more fluid when gently heated, but 
 decomposes at higher temperatures. It tastes and smells like the radicle itself. It is 
 insoluble in water, sparingly soluble in dilute alcohol and in ether, but dissolves 
 easily in absolute alcohol. The alcoholic solution precipitates metallic oxides from 
 their salts. Oxide of stibriamyl dissolves readily in acids, and the resulting compounds 
 are precipitated from their solutions by water. 
 
 1. The chloride, Sb(C 5 H 11 ) 3 Cl 2 , obtained by dissolving the oxide in hydrochloric 
 acid, is a yellowish translucent liquid, viscid at ordinary, comparatively mobile at higher 
 temperatures, heavier than water, soluble in alcohol and ether. It 'tastes and smells 
 like stibtriamyl. Decomposes at temperatures above 160 C. The bromide and iodide 
 resemble the chloride. 
 
 Nitr a t e. Sb(C 3 H n ) 3 .2N0 3 . When the chloride or iodide is mixed with an alcoholic 
 solution of nitrate of silver, as long as a precipitate forms, and then filtered, the filtrate 
 forms an emulsion, from which, after standing for some time in a warm place, two 
 liquids separate, the upper being light, yellow, and mobile, and the lower a deep 
 brown-red oil. The upper layer, when i-lowly evaporated, yields the nitrate in slender 
 white crystals grouped in stars ; they may be purified by recrystallisation from dilute 
 alcohol. The dark red oil likewise dissolves on addition of a large quantity of 
 hydrated alcohol, and the solution, after standing for some time, yields the same crys- 
 tals. These crystals melt at about 20 C. : the fused mass does not dissolve in alcohol 
 so readily as the crystals. This salt, the only crystallisable compound of stibtriamyl, 
 is insoluble in water and ether, but dissolves in hydrated alcohol. It has a peculiar 
 metallic taste. 
 
 The sulphate, Sb(C 5 H u )*.S0 4 , is formed by decomposing equivalent quantities of 
 sulphate of silver and a haloid compound of stibtriamyl dissolved in alcohol. This salt 
 was obtained only as an oily liquid body. 
 
 The white powder, formed by the action of the air upon stibtriamyl is insoluble in 
 ether, alcohol, and water : it does not dissolve in hydrochloric acid, but imperfectly in 
 fuming nitric acid ; slowly in aqua-regia. It remains unaltered even when strongly 
 heated, not decomposing below a rejd heat. Berle supposes it to be antimonite of stib- 
 triamyl, SbAm 3 O.Sb 2 3 . When sulphuretted hydrogen was passed for some time 
 through this compound suspended in alcohol, a white powder immediately separated, 
 which gradually assumed an orange colour, and then formed a pulpy mass, which could 
 ot be filtered. After addition of a large quantity of alcohol and ether the liquid, 
 
ANTIMONY-RADICLES (ORGANIC). 341 
 
 when left to stand in a warm place, deposited an orange-red, flocculent precipitate, 
 which, after drying, formed a brownish-yellow powder, insoluble in alcohol, ether, and 
 water ; this powder decomposed at a very high temperature, and took fire when 
 fuming nitric acid was poured upon it. Berle regards this compound as sulpkami- 
 monite of stibtriamyl, SbAm 3 S.Sb 2 S 3 (it gave 18-38 per cent, sulphur, the formula 
 requiring 17 '59). A compound, supposed to be identical with this, is formed by 
 passing sulphuretted hydrogen for some time through an alcoholic solution of oxide 
 of stibtriamyl. 
 
 Antimonides of EtbyJ, or Stibethyls. 
 
 STIBTRIETHYL or T RIETHYLSTI BINE, commonly called Stibctht/l. Sb(C 2 H 5 ) 3 = 
 SbE 3 . (L6 wig and Schweizer, Ann. Ch. Pharm. Ixxv. 315, 327; Lowig, ibid. Ixxx. 
 323 ; G m. ix. 79 ; Grerh. ii. 370.) This compound is prepared by the action of iodide of 
 ethyl on antimonide of potassium. The alloy is finely pulverised together with two or 
 three times its weight of quartz-sand (if pulverised alone it is apt to take fire) ; the 
 mixture is introduced into a number of small short-necked flasks, so as to fill them to 
 about two-thirds ; and iodide of ethyl is added in quantity just sufficient to moisten the 
 mixture of alloy and sand. The action begins in a few minutes, and is accompanied with a 
 rise of temperature sufficient to volatilise the excess of iodide of ethyl, which is collected 
 by itself in a small receiver ; as soon as this action is over, the flask is connected as 
 quickly as possible with a condensing apparatus, through which a stream of carbonic 
 acid gas is passed during the whole operation. This condensing apparatus consists of a 
 tall wide cylindrical vessel closed by a cork having three apertures. Through one of 
 these apertures, passes a tube proceeding from the carbonic acid apparatus, and reach- 
 ing to the bottom of the vessel; through the second a short straight tube to carry off 
 that gas, and through the third is inserted the distillation tube connected with the 
 flask containing the mixture : this tube descends nearly to the bottom of the glass 
 cylinder, and drops into the mouth of a small receiver, partly filled with antimonide of 
 potassium. This apparatus being completely filled with carbonic acid gas, the gener- 
 ating flask is heated very gently at first, and afterwards more strongly as long as any 
 liquid distils over. This flask is then removed, the distillation-tube stopped with 
 wax, till a second flask is ready to be adapted, and the operation is then repeated. 
 The contents of 20 to 24 flasks of 3 or 4 ounces capacity yield 4 or 5 ouuces of crude 
 product, which may thus be obtained in the course of a day. The receiver in which 
 the distillate has been collected is then closed while still immersed in the atmosphere 
 of carbonic acid, afterwards removed, and used as a retort in the rectification of the 
 product, the same condensing apparatus being used as before. The first portions of 
 the rectified product contain iodine, and deposit after a while, a number of colourless 
 crystals consisting of iodide of stibethylium. (Lowig and Schweizer.) 
 
 2. By the action of trichloride of antimony on zinc-ethyl, similarly to the preparation 
 of triethylphosphine. (Hofmann : See PHOSPHORUS BASES.) 
 
 Properties. Stibtriethyl is a transparent, colourless, mobile, strongly refracting liquid, 
 having a disagreeable alliaceous odour. Specific gravity 1*3244 at 16 C. It does not 
 solidify at 29 C. Boils at 158 0> 5 (bar. at 730 mm.). Vapour-density, by experi- 
 ment = 7'44 ; by calculation 7'18, the formula Sb(C 2 H 5 ) 3 , representing 2 volumes of 
 vapour. Stibtriethyl is insoluble in water, but dissolves readily in alcohol and ether. 
 
 A drop of Stibtriethyl exposed to the air at the end of a glass rod, emits thick white 
 fumes, and in a few seconds takes fire and burns with a white, strongly luminous 
 flame. When introduced in a thin stream into oxygen gas, it burns with dazzling 
 brightness. But if it be made to run into a glass globe containing air, in such a 
 manner as not to take fire, it gives off dense white fumes, which collect on the sides of 
 the vessel in the form of a powder, which is insoluble in ether, but dissolves in 
 alcohol and water ; at the same time a transparent, colourless, viscid mass is formed, 
 which is soluble in ether. This latter substance is the oxide of Stibtriethyl, SbE 3 ; 
 the powder is antimonite of Stibtriethyl, SbE 3 O.Sb 2 3 . Stibtriethyl oxidises very 
 slowly w r hen immersed in water ; hence it is best to keep it under that liquid. Sul- 
 phur, selenium, iodine, bromine, and chlorine combine directly with Stibtriethyl, the 
 action being always attended with evolution of heat, and in the case of bromine and 
 chlorine, with inflammation. The compounds contain 1 at. Stibtriethyl, with 1 at. of 
 a dibasic radicle, 0, S, SO 4 &c., or 1 at. stibethyl with 2 at. of a monobasic radicle, 
 Cl, Br, NO 3 , &c., in which respect they resemble the compounds of stibtrimethyl, ar- 
 sentriethyl (see p. 322). Stibtriethyl introduced into hydrochloric acid gas, yields chlo- 
 ride of Stibtriethyl and free hydrogen : 
 
 SbE 3 + 2HC1 = SbE 3 Cl 2 + H 2 . 
 
 The same reaction takes place with fuming hydrochloric acid. Dilute nitric acid, with 
 the aid of heat, acts on Stibtriethyl in the same manner as on the metals, evolving 
 
 z 3 
 
342 ANTIMONY-RADICLES (ORGANIC). 
 
 nitric oxide and forming nitrate of stibtriethyl. Neither fuming nitric acid nor aqua- 
 regia oxidises the antimony completely. 
 
 Antimonite of Stibtriethyl, Sb(C z H 5 ) 3 .Sb 2 4 , or SbE 3 O.Sb 2 3 , is formed, together 
 with the oxide, by the gradual oxidation of stibtrietliyl. The white fumes which 
 stibtriethyl diffuses in the air consist almost wholly of this compound. It may be pre- 
 pared by leaving an ethereal solution of stibtriethyl to evaporate spontaneously, and dis- 
 solving out the simultaneously formed oxide with ether-alcohol. The antimonite then 
 remains as a white, pulverulent, amorphous body. It has a bitter taste, and is soluble in 
 water and in alcohol. The aqueous solution prepared in the cold is perfectly mobile, 
 but when heated, becomes viscid like starch-paste, and dries up to a friable mass, 
 having the appearance of porcelain. Water poured upon this mass dissolves the 
 greater part, but leaves a small residue of antimonious oxide. Hydrochloric acid, 
 added to the alcoholic solution throws down chloride of stibtriethyl ; the acid liquid 
 separated from the chloride yields with sulphuretted hydrogen, a precipitate of kermes ; 
 on mixing it with water, powder of algaroth is precipitated. (Lowig.) 
 
 Bromide of Stibtriethyl^ Sb(C 2 H 5 ) 3 Br 2 . -Stibtriethyl takes fire when added by 
 drops to bromine. The bromide is prepared by adding a recently prepared alcoholic solu- 
 tion of bromine to an alcoholic solution of stibtriethyl cooled by ice, as long as the colour 
 of the bromine disappears. On mixing the solution with a large quantity of water, the 
 bromide of stibtriethyl is precipitated, in the form of a colourless liquid which must then 
 be washed with water and dried by contact with chloride of calcium. Transparent, 
 colourless, strongly refracting liquid, having a density of 1'953 at 17 C. Has an un- 
 pleasant odour like that of turpentine, and excites sneezing. Solidifies in a crystalline 
 mass at 10 C. It is not volatile. When distilled, it yields, among other products 
 a strongly acid liquid having an intolerable odour like that of chloral. It is 'decom- 
 posed by oil of vitriol, with evolution of hydrobromic acid, and by chlorine with separa- 
 tion of bromine. Insoluble in water, but dissolves readily in alcohol and ether. The 
 alcoholic solution gives with metallic salts, reactions similar to those of bromide of 
 potassium. 
 
 Chloride of Stibtriethyl. Sb(C 2 H 5 ) 3 Cl 2 . Stibtriethyl dropt into chlorine gas 
 takes fire and burns with a bright but smoky flame. Introduced into dry hydrochloric 
 acid gas, it forms chloride of stibtriethyl, and separates a quantity of hydrogen equal in 
 volume to half the hydrochloric acid gas. The chloride is easily obtained in the pure 
 state by decomposing a strong solution of nitrate of stibtriethyl with strong hydrochloric 
 acid ; it then separates in the form of a liquid which may be purified in the same 
 manner as the bromide. Transparent, colourless liquid, of specific gravity 1'540 at 
 17 C. ; it has a powerful odour like that of turpentine, and a bitter taste. Kemains 
 fluid at 12 C. When it is distilled with water, a small portion appears to volatilise 
 undecomposed ; when heated alone, it behaves like the bromide. Strong sulphuric 
 acid decomposes it, with evolution of hydrochloric acid, while, on the other hand, 
 hydrochloric acid added to a solution of sulphate of stibtriethyl throws down the 
 chloride. In other respects, its relations are like those of chloride of potassium or 
 chloride of sodium. It is insoluble in water, but dissolves readily in alcohol and ether. 
 
 Cyanide of Stibtriethyl appears to be formed when 2 at. cyanide of mercury, 
 and 1 at. sulphide of stibtriethyl are mixed in the state of aqueous solution. Sulphide of 
 mercury is then formed, together with a liquid which smells like prussic acid, and 
 behaves with metallic salts like cyanide of potassium. 
 
 Iodide of Stibtriethyl. Sb(C 2 H 5 ) 3 ! 2 . Iodine and stibtriethyl combine together 
 under water, with rise of temperature. On adding iodine to an ethereal solution of stib- 
 triethyl, a violent momentary ebullition takes places, and the iodine quickly disappears. 
 The iodide is, however, most easily prepared by adding iodine in small portions to an 
 alcoholic solution of stibtriethyl surrounded by a frigorific mixture, as long as the colour 
 of the iodine disappears, and leaving the colourless solution to evaporate. The iodide 
 then crystallises in colourless needles, which must be recrystallised from alcohol, and 
 afterwards from ether, to free them from a small quantity of adhering yellow powder. 
 
 Iodide of stibtriethyl has a slight odour of stibtriethyl and a bitter taste. It dissolves 
 in water without decomposition and readily in alcohol and ether. It melts and 
 solidfies at 70-5 C., sublimes in small quantity at 100, without alteration, but is 
 decomposed at a somewhat higher temperature, with formation of dense white fumes. 
 In the fused state, it is instantly decomposed by potassium, with separation of stibtri- 
 ethyl. With sulphuric acid and with metallic salts, it behaves like iodide of 
 potassium. Hydrochloric oc/<2 immediately precipitates chloride of stibtriethyl. Bro- 
 mine and chin-in-- separates the iodine; so likewise does nitric acid, forming nitrate of 
 Btibtriethyl. With zhw-cthyl it, appears to form stibpcntethyl, SbE 3 F + ZnE = 
 2ZnI + SbE 5 ; but this compound is decomposed Jy distillation into stibtriethyl, ethy- 
 
ANTIMONY-RADICLES (ORGANIC). 343 
 
 lene, and hydride of ethyl ; Sb(C 2 H 5 ) 5 = Sb(C 2 H 5 ) 3 + C 2 H 4 + C 2 H a . (B nekton, 
 Chem. Soc. Qu. J. xiii. 116.) 
 
 Oxy 'iodide of Stibtriethyl. (SbE 3 ) 2 FO = SbE 3 I 2 ,SbE 3 0. Produced by the 
 action of ammonia on iodide of stibtriethyl : 
 
 2SbE 3 F + 2NH 3 + H 2 = (SbE 3 )-I 2 + 2NH 4 I 
 
 also by mining the oxide and iodide of stibtrethyl in equivalent quantities. It forms 
 octahedral crystals containing 36-9 per cent, iodine: by calculation 37'1 (Strecker 
 Ann. Ch. Pharm. cvi. 306). Merck, who obtained this compound by mixing iodide of 
 stibtriethyl with an ethereal solution of stibtriethyl in an atmosphere of carbonic anhy- 
 dride, supposed it to be, not an oxyiodide, but a monoiodide of stibtriethyl SbE 3 I, and 
 explained its formation, together that with of another crystalline compound not 
 analysed, but supposed to be SbE 3 HI, on the hypothesis that the iodide of stibtri- 
 ethyl prepared by Lowig and Schweizer, really contained I at. hydrogen more than 
 those chemists supposed, its true formula being SbE 3 HF, or SbE 3 LHI : 
 
 SbE 3 HI 2 + SbE 3 = SbE 3 I + SbE'HI. 
 
 But the formula SbE 3 . 1 is contrary to analogy, the triethyl- and trimethyl-compounds of 
 arsenic, bismuth, and phosphorus, all uniting with 2 at. I, Br or Cl. Moreover Merck's 
 mode of preparation, which consisted in covering the liquid with a funnel, and passing 
 a stream of carbonic anhydride through the beak, till all the ether was evaporated, 
 was not very well adapted to exclude the air perfectly ; hence it is probable, especially 
 as the action took place but slowly, that oxide of stibtriethyl was first formed, and 
 then combined with the iodide. The oxyiodide might, however, be formed without 
 access of air, if the mixture was not perfectly dry, the compound SbE 3 HI being pro- 
 duced at the same time : thus, 
 
 2SbE 3 + 2SbE 3 F + H 2 = (SbE 3 ) 2 I 2 + 2SbE 3 HI 
 
 The oxyiodide treated with hydriodic acid yields iodide of stibtriethyl and water * 
 (SbE 3 ) 2 FO + 2HI = 2SbE 3 F + H 2 
 
 With oxide of silver, it yields oxide of stibtriethyl, SbE 3 0, and with chloride of 
 mercury, an oxychloride of stibtriethyl, (SbE 3 ) 2 Cl 2 0. (Strecker.) 
 
 Merck supposed that the action of various mercury and silver-salts on his supposed 
 iodide, SbE 3 I, yielded a series of compounds of analogous constitution, viz. a chloride, 
 SbE'Cl, an oxide (SbE 3 ) 2 0, &c. 
 
 Nitrate of Stibtriethyl. Sb(C 2 H 5 ) 3 .2N0 3 . Obtained by saturating dilute nitric 
 acid with oxide of stibtriethyl, or by dissolving stibtriethyl in the dilute acid with the 
 aid of heat. In this latter reaction, nitric oxide is evolved, and a small quantity of 
 antimonious oxide separates. The salt may be obtained in crystals by evaporating the 
 solution. At 62-5 C. it melts into a transparent liquid, which solidifies to a crystal- 
 line mass at 57 ; at a higher temperature, it deflagrates like a mixture of nitre and 
 charcoal. It dissolves easily in water, less easily in alcohol, and is nearly insoluble in 
 ether. The solutions have an acid reaction and bitter taste. 
 
 Oxide of Stibtriethyl. Sb(C 2 H 5 ) 3 0. Formed by the direct oxidation of stibtri- 
 ethyl, either in the free state, as above mentioned, or dissolved in alcohol or ether ; as 
 thus obtained, however, it is always more or less mixed with antimonite of stibtriethyl, 
 especially when obtained from the ethereal solution. The alcoholic solution on the 
 contrary yields but a small quantity of antimonite. Accordingly, the oxide may be 
 obtained by leaving a dilute alcoholic solution to evaporate slowly in a loosely covered 
 foot-glass, treating the residue with ether, which dissolves the oxide and leaves the 
 antimonite, and repeating this treatment as long as the ether leaves any insoluble 
 residue. The oxide may also be obtained by treating an aqueous solution of sulphate 
 of stibtriethyl with baryta-water ; evaporating the filtrate over the water-bath ; ex- 
 hausting the residue with alcohol, which dissolves out a compound of oxide of stibtri- 
 ethyl and baryta ; precipitating the baryta by carbonic acid, and evaporating the 
 filtered alcoholic solution. An alcoholic solution of stibtriethyl shaken up with finely 
 divided red oxide of mercury, quickly reduces the mercury to the metallic state, and 
 yields pure oxide of stibethyl. 
 
 Oxide of stibtriethyl in its purest state, is a transparent, colourless, viscid, amorphous 
 mass, which dissolves readily in water and alcohol, somewhat less readily in ether ; 
 has a very bitter taste ; does not appear to be poisonous ; is not altered by exposure 
 to the air ; is not volatile ; but when heated in a tube, gives off white vapours which 
 burn with a bright flame, and leaves a residue containing antimony and charcoal. It 
 is decomposed by potassium, at a gentle heat, with separation of stibtriethyl. Fuming 
 nitric add decomposes it, with evolution of light and heat ; dilute nitric and str<ig 
 sulphuric acid dissolve it, forming salts of stibtriethyl ; hydrochloric acid and other hy- 
 drogen-acids dissolve it in the form of chloride of stibtrictliyl and similar compounds, 
 
 z 4 
 
344 ANTIMONY-RADICLES (ORGANIC). 
 
 Hydrosulphuric add has no perceptible action upon it ; but on evaporating a solution 
 of the oxide saturated with the gas, crystals of sulphide of stibtriethyl are obtained ; the 
 smallest trace of antimonite of stibtriethyl mixed with the oxide is detected by the 
 formation of a yellow precipitate. 
 
 Sulphate of Stibtriethyl, Sb(C 2 H 5 ) 3 .S0 4 , is obtained by decomposing the aqueous 
 solution of the sulphide with sulphate of copper. It crystallises in small white prisms, 
 soluble in water and alcohol, inodorous, but having a bitter taste and acid reaction. 
 
 Sulphide of Stibtriethyl, Sb(C 2 H 5 ) 3 S, is formed, with evolution of heat, when sul- 
 phur and stibtriethyl are brought together under water. But it is most readily obtained 
 by boiling an ethereal solution of stibtriethyl with flowers of sulphur; the liquid decanted 
 from the sulphur soon solidifies in needle-shaped crystals, which may be purified by 
 leaving the adhering sulphur to oxidise in the air, and crystallising several times from 
 ether. Sulphide of stibethyl thus purified forms a bulky mass, having a silvery lustre, 
 an unpleasant odour, and a bitter taste ; it is permanent in the air when dry, melts 
 above 100 C., and is decomposed by a stronger heat, with evolution of stibtriethyl va- 
 pour. The aqueous solution of the sulphide precipitates metals from their solutions 
 as sulphides, and yields sulphuretted hydrogen with dilute acids. 
 
 Sulphantimonite of Stibtriethyl. SbE 3 .Sb 2 S 4 , or SbE 3 S.Sb 2 S 3 . Sulphuretted 
 hydrogen passed through a solution of the antimonite, throws down this compound in 
 the form of a light yellow precipitate, having an extremely unpleasant, persistent odour, 
 like that of mercaptan. The compound is also formed by adding recently precipitated 
 trisulphide of antimony to a solution of sulphide of stibtriethyl, the latter being in ex- 
 cess, whereupon the brown-red colour of the kermes immediately changes to light yellow. 
 Dried over sulphuric acid, it forms a powder of a beautiful light yellow colour, which 
 changes to brown-red at the heat of the water-bath. When distilled over a spirit- 
 lamp, it yields a liquid distillate having all the properties of sulphide of stibtriethyl. 
 Dilute sulphuric acid poured upon it, separates trisulphide of antimony, with evolution 
 of sulphuretted hydrogen, and formation of sulphate of stibtriethyl : 
 SbE 3 .Sb 2 S 4 + S0 4 H 2 = SbE 3 .S0 4 + H 2 S + Sb 2 S s . 
 Fuming nitric acid decomposes it, with emission of light and heat. 
 
 STIBETHYLIUM. Sb(C 2 H 5 ) 4 = SbE 4 . (E. Lowi'g, J. p. Chem. Ixiv. 415; Chem. 
 Soc. Qu. J. viii. 261; Grm. x. 527.) The iodide of this radicle is formed by intro- 
 ducing a mixture of equal parts of stibtriethyl and iodide of ethyl into a retort filled 
 with carbonic acid gas, nearly filling the retort with water, sealing the neck, and then 
 heating it in boiling water. The solution evaporated and cooled, yields beautiful hexa- 
 gonal prisms, often an inch long, containing 2SbE 4 I.3H 2 0, and other crystals, con- 
 taining 4SbE 1 I.3H 2 O. The salt has a very bitter taste, and 1 pt. of it dissolves iu 
 5-26 pts. of water at 20 C. It dissolves more easily in absolute alcohol, but less in ether. 
 The solution of this salt, mixed with chloride of mercury, forms a white precipitate, which 
 dissolves in warm water, and yields crystals containing 3HgI.SbE 4 I. Another double 
 iodide, 3HgI.2SbE 4 I, is obtained by adding iodide of mercury to a hot solution of iodide 
 of stibethylium. 
 
 The iodide digested with oxide of silver, yields a strongly alkaline solution, which 
 when evaporated, leaves the hydrate of stibethylium in the form of a thick colourless 
 oily liquid, having a strong alkaline taste and reaction. It expels ammonia from its 
 compounds, precipitates metallic oxides, and redissolves alumina and stannic oxide. It 
 dissolves in acids, forming salts which have a bitter taste. The carbonate is a tough 
 deliquescent mass. The sulphate and nitrate crystallise. The formate yields needle- 
 shaped crystals, difficult to dissolve. The acetate forms similar crystals, but more 
 soluble. The oxalate crystallises ; the succinate does not. The neutral tartrate and 
 racemate form large deliquescent crystals ; the acid tartrate, fine needles. 
 
 The sulphide, (SbE 4 ) 2 S, is obtained by treating the oxide with hydrosulphuric acid. 
 It is a yellowish oily liquid, soluble in water and alcohol, and exhibiting the reactions 
 of alkaline sulphides. The bromide and chloride are crystalline compounds obtained 
 by saturating the oxide with the corresponding acids. The chloride forms with chloride 
 of mercury, compounds analogous to the double iodides above mentioned. It also com- 
 bines with dichloride of platinum, producing the compound 3PtCl 2 .2SbE 4 Cl, which 
 forms fine yellow crystals, soluble in water and alcohol. 
 
 Antimonldes of Methyl.* 
 
 STIBTRIMBTH YL. Sb(CH 3 ) 3 = SbMe 3 . Produced, like the corresponding ethyl-com- 
 pound, by the action of iodide of methyl on antimonidc of potassium. It is a colourless 
 heavy liquid, insoluble in water, sparingly soluble in alcohol, readily in ether. When 
 exposed to the air, it gives off thick white fumes, and takes fire, burning with a white 
 
 Landolt, Ann. Ch. Pharm. Ixxviii. 91 ; Cm vii. 321 ; Gerh. i. 646. 
 
ANTIMONY-RADICLES (ORGANIC). 345 
 
 flame and depositing metallic antimony. Its compounds are precisely analogous to 
 those of stibtriethyl. 
 
 Stibpentamethyl, Sb(CH 8 ) 5 , appears to be produced by the action of zinc-ethyl on 
 stibtrimethyl; and to be decomposed by distillation into stibtrimethyl and hydro- 
 carbons. (Buck ton, compare page 336.) 
 
 STIBMETHYLIUM. Sb(CH 3 ) 4 = SbMe 4 . This compound is obtained as an iodide 
 by the action of iodide of methyl on stibtrimethyl. It is not quite certain whether it has 
 yet been isolated. The iodide distilled with excess of antimonide of potassium, in an 
 atmosphere of carbonic anhydride, yields a spontaneously inflammable oily liquid, re- 
 sembling stibtrimethyl ; and the aqueous solution of the iodide subjected to the action 
 of the electric current, yields iodine at the positive pole, while at the negative pole, the 
 liquid becomes alkaline, and gives off a spontaneously inflammable gas containing 
 antimony, and having the odour of stibtrimethyl ; but which of these products, if either, 
 is stibmethylium, has not yet been ascertained. 
 
 The compounds of stibmethylium closely resemble the corresponding potassium-salts, 
 and are isomorphous with them. They have a bitter taste. They are decomposed by 
 potash or soda, and then form white fumes, if a glass rod moistened with hydro- 
 chloric acid is held over them. They are for the most part easily soluble in water, 
 less soluble in alcohol, and insoluble in ether. The antimony in them is scarcely 
 recognisable by the ordinary reagents, not being precipitated by hydrosulphuric acid 
 till after a long time. They yield a slight deposit of antimony, when treated with 
 zinc andsulphuric acidin Marsh's apparatus. They bear a heat of about 140C. without 
 decomposition, but between 180 and 200 they are decomposed, and give off spon- 
 taneously inflammable vapours. 
 
 Bromide. SbMe 4 Br. Obtained by decomposing iodide of stibmethylium with 
 bromide of mercury. On filtering from the iodide of mercury and evaporating, a 
 beautiful salt is obtained, soluble in alcohol and water, but insoluble in ether, and 
 having a saline bitter taste. This compound, when heated, evolves white vapours 
 which take fire in the air. Oil of vitriol poured upon it liberates hydrobromic acid ; 
 nitric acid separates bromine. "With metallic salts, bromide of stibmethylium behaves 
 in the same manner as bromide of potassium. 
 
 Carbonates. The neutral carbonate is obtained by decomposing a solution of the 
 iodide with recently precipitated carbonate of silver. The filtered liquid evaporated 
 over the water-bath, leaves an indistinctly crystallised, somewhat yellowish, transparent 
 mass, which deliquesces very readily in the air, exhibits an alkaline reaction, dis- 
 solves very easily in water and in alcohol, but very slowly in ether. This com- 
 pound is very unstable, beginning to smell of stibtrimethyl as soon as it is formed. 
 When heated, it gives off white fumes, which take fire spontaneously in the air. It 
 does not appear to contain water of crystallisation. The acid carbonate, (SbMe.H.)CO 3 , 
 is formed by passing carbonic anhydride through a solution of the oxide or of the 
 neutral carbonate, and evaporating. It crystallises with difficulty in small deliquescent 
 needles, arranged in stars. In the solid form, it soon decomposes, like the neutral 
 carbonate. The aqueous solution evolves carbonic anhydride when heated, and does 
 not precipitate magnesium-salts. 
 
 Chloride. SbMe 4 Cl. Obtained by adding a hot solution of corrosive sublimate to 
 aqueous iodide of stibmethylium, as long as a precipitate of iodide of mercury is pro- 
 duced. The filtered liquid evaporated over the water-bath deposits the chloride in 
 white six-sided tables, similar to those of the iodide. These crystals are easily soluble 
 in water and alcohol, nearly insoluble in ether : their taste is saline and bitter. Tin's 
 salt intumesces when heated in a tube, and at a higher temperature gradually dis- 
 appears, giving off white fumes, which take fire spontaneoiisly in the air, and deposit 
 on the cooler part of the tube a white sublimate containing chloride of antimony. 
 
 Chloroplatinate. SbMe 4 Cl.PtCl 2 . Obtained as a yellow crystalline precipitate, by 
 adding dichloride of platinum to chloride of stibethylium. It may be dissolved in 
 boiling water, and separates on cooling as an orange-yellow crystalline powder. It is 
 the least soluble in water of all the salts of stibmethylium, and is intermediate in solu- 
 bility between the chloroplatinates of potassium and sodium. It is quite insoluble in 
 alcohol and ether, very difficult of solution in alkalis, but dissolves more easily in hot 
 hydrochloric acid. When heated, it turns black, and soon takes fire, leaving an allo}' 
 of platinum and antimony, from which the latter metal is but imperfectly removed by 
 aqua-regia. 
 
 Hydrate. SbMe 4 .H.O. Obtained by agitating an aqueous solution of the iodide 
 with recently precipitated oxide of silver, filtering from the resulting iodide of silver, 
 aivrJ evaporating the filtrate in vacuo over sulphuric acid. It is a white, crystalline 
 mass which feels soapy between the fingers, is highly caustic, and dissolves rapidly in 
 
346 ANTIMONY-RADICLES (ORGANIC). 
 
 water and alcohol, but is insoluble in ether. In the state of aqueous solution, it is 
 slightly volatile, and forms white fumes when a glass rod moistened with hydrochloric 
 acid is held over it ; but the solution, when evaporated over the water-bath, yields the 
 original quantity with scarcely any loss. When the solid hydrate is suddenly heated 
 in a test-tube, it gives off vapours which take fire on coming in contact with the 
 air, and deposit metallic antimony; but when carefully heated, it sublimes unde- 
 composed. 
 
 The aqueous solution has an alkaline taste and odour, and instantly turns reddened 
 litmus paper blue. In all its chemical relations, it exhibits the closest resemblance to 
 caustic potash. When evaporated in an open vessel, it absorbs carbonic acid, and then 
 effervesces strongly with acids ; but on the addition of lime-water, carbonate of calcium 
 is precipitated, and the pure base is again found in the solution. It expels ammonia 
 from ammoniacal salts, even in the cold, and separates baryta from iodide of barium. 
 Lime and oxide of lead are immediately precipitated by the solution of this base. 
 With zinc-salts it forms a white precipitate, soluble in excess ; with copper-salts a pre- 
 cipitate insoluble in excess; with mercurous, mercuric, and silver-salts, it gives the 
 same reactions as potash; with chloride of platinum, it forms a yellow precipitate, 
 resembling the chloroplatinate of potassium. The aqueous solution, boiled with sulphur, 
 forms a yellow liquid, which, when mixed with dilute acids, yields a precipitate of 
 sulphur, and gives off sulphuretted hydrogen. 
 
 Iodide of Stibmethylium, SbMe 4 !, is formed by the action of iodide of methyl on 
 stibtrimethyl. If, in the preparation of stibtrimethyl, the iodide of methyl which distils 
 over at first, and the stibtrimethyl which passes over when the temperature is raised, are 
 collected in the same receiver, a slight ebullition takes place, and the liquid mixture 
 solidifies after a while into a perfectly white, crystalline mass. This is dissolved in 
 warm water, the excess of iodide of methyl separated, and the solution set aside to 
 evaporate slowly over the water-bath. The iodide of Stibmethylium then separates in 
 crystals belonging to the hexagonal system. They are remarkably beautiful, large, 
 six-sided tables, usually scalariform, and from 10 to 15 millimetres in diameter; the 
 terminal faces are plane, and the lateral edges intersect one another at angles of 120. 
 The crystals contain water mechanically enclosed, and consequently decrepitate when 
 heated. They dissolves in 3*3 pts. of water at 23 C., and are likewise easily soluble in 
 alcohol, but dissolve very slowly in ether. Iodide of Stibmethylium heated in a test- 
 tube first falls to powder, and at 200 C. begins to decompose, disappearing gradually, 
 and evolving thick white fumes, which have the odour of stibtrimethyl. The vapour thus 
 evolved is partly deposited as a coating on the inside of the tube ; but the greater 
 portion reaches the mouth, where it takes fire spontaneously, forming rings of smoke 
 like phosphoretted hydrogen. Boiling water dissolves but a small portion of the 
 deposit in the tube. The solution treated with nitrate of silver, yields a precipitate 
 consisting of iodide of silver and metallic silver, the latter being doubtless produced 
 by pure stibtrimethyl or Stibmethylium, the former by undecomposed iodide. The aqueo us 
 solution of iodide of Stibmethylium is gradually decomposed by repeated evaporation, 
 a small quantity of a yellow insoluble substance (not yet examined) being formed, and 
 the odour of stibtrimethyl evolved. The yellow substance likewise appears, though not 
 constantly, when the solution is exposed to sunshine. [For the decomposition by electro- 
 lysis, see page 345.] Filtering paper, covered with strong starch-paste, to which iodide 
 of Stibmethylium has been added, behaves towards ozone, exactly in the same manner as 
 paper prepared with iodide of potassium, but is even more sensitive. Sulphuric acid, 
 bromine, chlorine, and nitric acid, act upon iodide of Stibmethylium exactly as upon 
 iodide of potassium ; hydrochloric acid decomposes it, with formation of chloride of 
 Stibmethylium. Aqueous solution of iodide of Stibmethylium poured upon amalgam 
 of sodium, produces a succession of little explosions, accompanied by appearance of 
 fire, metallic antimony being also separated. The iodide distilled with excess of an- 
 timonide of potassium, yields a yellow oily liquid, which is perhaps Stibmethylium. 
 The aqueous solution dissolves a considerable quantity of the yellow modification 
 of mercuric iodide. The red iodide boiled in the solution changes into the yellow 
 modification before it dissolves ; and as the liquid cools, a considerable portion of the 
 mercuric iodide separates out, but always in the yellow modification. 
 
 Nitrate of Stibmethylium, SbMe 4 .N0 3 . Formed by adding nitrate of silver to 
 an aqueous solution of iodide of Stibmethylium as long as any precipitate is formed, 
 then filtering and evaporating till the salt crystallises. The crystals are anhydrous. 
 The salt dissolves readily in water, slowly in alcohol or ether. Its taste is harsh and 
 bitter, not cooling like that of nitre. When heated, it gives off white fumes, which im- 
 mediately take fire ; the entire mass then explodes with a large white flame, just like 
 a mixture of nitre and charcoal. The salt is very stable, not being decomposed, even 
 by boiling with strong sulphuric acid. 
 
ANTIMONY-RADICLES (ORGANIC). 347 
 
 Sulphates of Stibmethylium. The neutral sulphate, (SbMe 4 ) 2 .S0 4 , is obtained 
 by adding a hot solution of sulphate of silver to aqueous iodide of stibmethy Hum, as long 
 as any precipitate of iodide of silver is formed. On evaporating the filtered liquid over 
 the water-bath, colourless crystals are obtained, which maybe pressed between paper and 
 dried in the air; also, by saturating a concentrated solution of the acid salt with oxide of 
 stibmethylium, and mixing the aqueous solution with alcohol and ether ; the neutral salt 
 then separates in oily drops, which after a while assume the solid form. The crystals, 
 which appear to be rhombic, contain 15'42 per cent. (5 at.) water of crystallisation, 
 which they give off at 100 C. Placed over sulphuric acid, they lose part of their water, 
 and fall to a white powder. The crystals dissolve very readily in water ; the anhy- 
 drous salt becomes strongly heated when water is poured upon it. The salt is also 
 soluble in alcohol, but insoluble in ether. Its taste is saline and bitter. 
 
 Add Sulphate, (SbMe 4 ).H.S0 4 . Obtained by adding 1 at. sulphuric acid to an 
 aqueous solution of 1 at. of the neutral sulphate. After several crystallisations, 
 beautiful, hard, transparent crystals are obtained, some of which are four-sided tablets 
 with obliquely truncated edges. It has a strongly acid taste, leaving a bitter taste in 
 the mouth. When heated, it behaves exactly like the neutral sulphate. On dissolving 
 it in a small quantity of water, then adding alcohol, precipitating by ether, and re- 
 peating these operations several times, the neutral sulphate is at length obtained. 
 In this respect, the acid salt behaves exactly like acid sulphate of potassium. The 
 salt contains no water of crystallisation. The basic water (or hydrogen), like that of 
 acid sulphate of potassium, is not driven off at 120 C. 
 
 Sulphide, (SbMe 4 ) 2 S. Prepared, like monosulphide of potassium, by dividing an 
 aqueous solution of oxide of stibmethylium into two parts, saturating the one with 
 hydrosulphuric acid, and then adding the other. The resulting solution, quickly eva- 
 porated in a retort, leaves the sulphide in the form of an amorphous green powder, 
 which smells like mercaptan, dissolves readily in water and alcohol, but is insoluble in 
 ether. The solutions give black precipitates with lead- and silver-salts. Heated in a 
 tube, it melts and decomposes, giving off spontaneously inflammable vapours, and 
 leaving sulphide of antimony. In contact with the air, it oxidises rapidly. 
 
 A solution of hydrate of stibmethylium boiled with sulphur, yields milk of sulphur 
 on the addition of an acid : hence it is probable that higher sulphides of stibmethylium 
 may be formed. 
 
 STiBTRiMETHYLETHYLiUM,Sb(CH 3 ) 3 (C 2 H 5 ), is obtained as an iodide by the action 
 of iodide of ethyl on stibtrimethyl. It closely resembles the iodide of stibmethylium. 
 
 STIBMETHYLTRIETHYLIUM, Sb(CH 3 )(C 2 H 5 ) 3 = SbMeE 3 . (Friedlander, J. pr. 
 Chem. Ixx. 443 ; Grm. xiii. 500). The iodide of this radicle, obtained by the action 
 of iodide of methyl on stibtriethyl, forms beautiful crystals, apparently having the 
 form of rhombic prisms, with a glassy lustre when fresh, changing after a while to 
 nacreous ; they crumble to pieces when dry, but are otherwise permanent in the air. 
 The iodide has an intensely bitter taste, is inodorous when cold, but at 100 C. gives 
 off a peculiar odour, without sensible decomposition. It dissolves in twice its weight 
 of water at 20 C., is soluble also in alcohol, but insoluble in ether. The solutions 
 turns the plane of polarisation to the left. 
 
 Iodide of stibmethyltriethylium forms two double salts with mercuric iodide, viz. 
 SbMeE 3 !. 2HgI, obtained by adding recently precipitated mercuric iodide to a solution 
 of iodide of stibmethyltriethylium ; and SbMeE 3 I.3HgI, which is precipitated on adcl- 
 ding a hot solution of mercuric chloride to a boiling solution of iodide of stibmethyl- 
 triethylium, the chloride of the antimony-radicle then remaining in solution : 
 
 4SbMeE 8 I + 3HgCl = SbMeE 3 !. 3Hg! + 3SbMeE 3 CL 
 
 This double iodide is insoluble in water; and sparingly soluble in alcohol and ether, 
 crystallising from the alcoholic solution in yellow needles which melt below 100 C. 
 
 Chloride, SbMeE 3 Cl. Produced as above, or by dissolving the hydrate or carbonate 
 in hydrochloric acid, and may be obtained by evaporation in small crystalline needles. 
 
 Hydrate. Produced (1), by decomposing the iodide with moist oxide of silver (when 
 thus prepared, however, it always contains silver) ; or (2), by decomposing the sul- 
 phate with an exactly equivalent quantity of hydrate of barium, and concentrating the 
 filtrate in vacuo. It is a thick, oily, non-volatile liquid, which has a strong bitter 
 taste and alkaline reaction, decomposes ammonia-salts, and precipitates metallic oxides 
 from their solutions, the zinc and alumina precipitates being soluble in excess. 
 
 Hydrate of stibmethy Itriethylium dissolves in acids, forming neutral and acid salts, 
 which may likewise be prepared by double decomposition from the iodide, chloride, or 
 sulphate. The salts arc more or less soluble in water and alcoho A ; some are deliques- 
 cent, others permanent. Those which crystallise do not contain water. There are 
 no basic salts of stibmethy Itriethylium, 
 
348 ANTIPHLOGISTIC THEORY APATITE. 
 
 The carbonate, (SbMeE s ) 2 .C0 3 , is a white resinous mass which reacts like carbonate 
 of ammonium. The sulphate, (SbMeE 3 )-.SO' is produced by dissolving the hydrate 
 in sulphuric acid, or by decomposing the iodide with sulphide of silver, and may be 
 obtained, by evaporation in vacuo, in white, shining, bitter crystals, which melt at 
 100 C. and are extremely deliquescent. 
 
 The acetate, formate, and butyrate are crystalline. The neutral oxalate, 
 (SbMeE 3 ) 2 .C' 2 4 , forms anhydrous glassy needles, moderately soluble in water. The 
 acid oxalate, SbMeE 3 .H.C a 4 , forms needles very soluble in water. The tartrate is 
 obtained by evaporation as a syrupy liquid which rapidly absorbs water, but does not 
 crystallise. 
 
 The cyanide is obtained by dissolving the hydrate in hydrocyanic acid. The clear 
 watery solution boiled with potash-ley gives off ammonia and forms an antimonetted 
 acid, which yields insoluble or sparingly soluble salts with all bases, except potash, 
 soda, and ammonia. 
 
 ANTIPHLOGISTIC THEORY. See COMBUSTION. 
 
 ANTII&RHIN. See ANTHOK.IRRIN. 
 
 ANTIRRHINIC ACID. An acid of unknown composition, obtained by Morin 
 from the leaves of the fox-glove (Digitalis purpurea). It is prepared by distilling the 
 leaves with water, saturating the distillate with baryta, evaporating, distilling the 
 residue with excess of sulphuric or oxalic acid, and rectifying over chloride of calcium. 
 The acid then floats on the top of the liquid in oily drops, having an unpleasant odour 
 like that of the plant, and producing headache and giddiness. It reddens litmus 
 strongly, dissolves readily in alcohol, and in contact with water forms white films, 
 which gradually dissolve. (J. Pharm. April 1845, p. 299.) 
 
 ANTISEPTICS. Substances which prevent the spontaneous decomposition of 
 vegetable and animal substances. They are chiefly : the mineral acids, the alkaline 
 hypochlorites, common salt, nitre, spices, sugar, creosote and yeast. (See FERMENT- 
 ATION and PUTREFACTION.) 
 
 ANTXTARTARIC ACID, also called L&votartaric and Lcevoraccmic acid. 
 Pasteur has shown that racemic acid, which has no action on polarised light, is a com- 
 pound of two acids in equal proportions, one of which turns the plane of polarisation of a 
 ray of light to the right, and the other to the left. Hence he calls these acids re- 
 spectively, d(xtro- and Icevoracemic acids, or dextro- and l&vo-tartaric. The dextro- 
 acid is identical with ordinary tartaric acid. Gmelin (Handb. x. 365) retains the 
 name tartaric for the ordinary dextro-rotatory acid, and distinguishes the Isevo- 
 rotating acid as antitartaric acid. (See TARTARIC and EACEMIC ACIDS.) 
 
 ANTRIIVIOZiITE. A hydrated silicate of aluminium, found in white stalactitic 
 masses on the north coast of Antrim. According to Th. Thompson's analysis (J. pr. 
 Chem. viii. 489) it contains 43-47 per cent, of silica, 30'26 alumina, and 15'32 water, 
 together with 7'50 per cent, lime, 4*10 potash, 0'19 protoxide of iron, and 0*098 
 chlorine. It appears to be related to mestoype. 
 
 ANTS, OIXi OP. The red ant (Formica rufa) contains a volatile oil, which may 
 be extracted by distilling the insects with water : to the amount of 0-12 per cent., 
 according to Nolle ; 1 per cent, according to Hermbstadt. It is transparent and colour- 
 less, and has an agreeable odour ; its taste is not burning. It is slightly soluble in 
 absolute alcohol. (Grm. xiv. 358.) 
 
 ANTYHRHINIC ACID. The name given by Walz to a volatile acid, obtained 
 by distilling toad-flax (Antirrhinum Linaria, L., Linaria vulgaris, Dec.) with water. It 
 forms a deliquescent barium-salt, the analysis of which gives for the atomic weight of 
 the acid the number 212. 
 
 ANYIiAIVSIDE. Syn. with Nitrosalicylamide. See SALICYLAMIDE. 
 
 APATEI.ITE. A native basic sesquisulphate of iron = 2(Fe 4 3 .3S0 3 ) + 3H 2 0, 
 found, in egg-shaped, earthy, yellow masses, in the clay, at Meudon and Auteuil, near 
 Paris. 
 
 APATITE. Phosphate of calcium. This mineral occurs both massive and crys- 
 tallised. The crystals are six-sided prisms, belonging to the rhombohedral system, 
 sometimes passing into the six-sided table ; often hemihedral. Lustre vitreous, in- 
 clining to subresinous. Translucent, rarely transparent. Scratches fluor-spar, but is 
 scratched by felspar.^ Brittle. Colours, white, wine-yellow, green, and red. Specific 
 gravity 3'17 to 3'25. Phosphoresces on coals. Electric by heat and friction. It 
 occurs in primitive rocks ; in the tin veins of the granite of St. Michael's Mount, 
 Cornwall ; near Chudleigh in Devonshire ; at Nantes in France ; on the St. Gothard ; 
 and with molybdenum in granite, near Colbeck, Cumberland ; also at Elirenfrie- 
 
APATOID APIITONITE. 349 
 
 dersdorf, in Saxony, in the Tyrol, in Bavaria, in Bohemia, and in Spain. Large 
 crystals are found near New York one crystal from Robinson's farm being nearly a 
 foot in length, and weighing 18 pounds also in New Hampshire, in Maine, Massa- 
 chusets, and Delaware. A massive variety called Phosphorite, because it becomes phos- 
 phorescent by friction, is found in veins of tin-stone, and likewise in secondary forma- 
 tions. A very large vein of this mineral is found at Estremadura in Spain. It has a 
 botryoi'dal ai?d kidney-shaped surface, and a radiating fibrous texture. 
 
 The chemical composition of apatite may be expressed, according to Gustav Kose 
 
 (Pogg. Ann. ix. 185), by the general formula, 3P0 4 Ca 3 + QJJ Q, the chlorine and 
 
 fluorine, which are isomorphous, being capable of replacing one another in any pro- 
 portion whatever. If the chlorine is altogether absent, the mineral becomes a Fluor- 
 apatite, or Francolite, 3P0 4 Ca 3 -t- CaF, containing 7 '9 per cent, fluoride of calcium, 
 and 92-31 tribasic phosphate. An analysis of Francolite by Dr. Henry gives in 100 
 pts. 41-34 phosphoric anhydride (P 2 5 ), 53'38 lime (Ca 2 0), 2'96 protoxide of iron (Fe 2 O), 
 2 '32 fluorine, and a trace of chlorine; whence we may calculate that the proportion 
 of tribasic phosphate of calcium is 93*3, and that of the fluoride 4'91 ; part of the 
 theoretical quantity of calcium is, however, replaced by the iron. The apatites of the St. 
 Gothard, of Ehrenfriedersdorf in Saxony, and of Faldigl and Greiner in the Tyrol, are 
 fluor-apatites. Apatites free from fluorine have not yet been found. The greater num- 
 ber contain chlorine and fluorine together. The largest amount of chloride of calcium 
 is found in the apatite of Snarum in Norway, which contains 4-28 CaCl, 1*59 CaF, and 
 91-13 P0 4 Ca 3 . An apatite in which the fluorine was wholly replaced by chlorine 
 would contain 10-62 per cent, of chloride of calcium. 
 
 The composition of apatite is only a particular case of the general formula 
 
 3 [ . 4 .M S J + , j-p in which M denotes a metal, which, in the species hitherto exa- 
 mined, may be either calcium or lead, and in which phosphorus and arsenic may replace 
 each other in any proportion, as well as chloi'ine and fluorine. This formula likewise 
 includes the pyromorphites, or green lead-ores, which are isomorphous with apatite. 
 Apatite was so named by Werner from airareiv, to deceive, on account of the mistakes 
 of the earlier mineralogists respecting its nature. Even Berzelius was not aware of 
 the presence of phosphorus in it. (Handw. d. Chem. 2 te Aufl. ii. 147.) 
 
 APATOID. A mineral free from phosphoric acid, found in certain American 
 meteorites. 
 
 APEX.AXC ACID. See AZELAIC Acn>. 
 APHACTESITE. See ABICHITE (p. 6). 
 AFHAX3TTE. See DlOBITE. 
 
 APHXiOGXSTXC X* AMP. Lamp without flame, or glow-lamp. (See ALCOHOL, 
 p. 74.) 
 
 APHRITE. Schie/erspar. Chaux carbon atee nacree. A slaty carbonate of 
 calcium, having a mother-of-pearl lustre, found rarely in beds and veins in the older 
 rocks, as in Cornwall, at Kongsberg, &c. A soft friable variety of it, called earth-foam 
 (SchaumJcalk, Schaiimerde), containing silica and oxide of iron, is found at Gera, and 
 at Eisleben in Thuringia. 
 
 APHRIZITE. See TOUKMAXINE. 
 
 APHRODITE. A hydratod silicate of magnesium, resembling meerschaum, 
 found at Longbanshytta, in Sweden. Its formula is 16Mg-0.15Si0 2 + 12H-O. 
 Now in the magnesia-silicates, 3 at. water may be supposed to replace 1 at. magnesia 
 (see SILICATES) hence the preceding formula may be reduced to 4M"0.3Si0 2 , or 
 ZMO.SiO 3 [M denoting a monatomic metal]. 
 
 APHRONTTR1TIVE, (&4>pos froth and virpov soda.) An old name for the saline 
 efflorescences formed on walls, commonly called wall-nitre, but consisting for the most 
 part of carbonate and sulphate of sodium, sometimes with sulphate of magnesium. 
 
 APHROSIDERITE. A silicate of iron and aluminium, containing, according to 
 Sandberger, 26-4 per cent, silica, 21*2 alumina, I'l magnesia, 44*2 protoxide of iron, 
 and 7'7 water. Sandberger represents it by the formula 3(3FeO.SlG 3 ) + 
 SAP&.SiO 3 f 6HO. It is doubtful, however, whether all the iron exists as protoxide. 
 
 APHTAX.OSE. See ARCANITE. 
 
 APHTOXTITE. The name given by Svanberg to a mineral from Wiirmkog, in 
 "Warmeland, resembling fahl-ore (q. v.\ but distinguished by a peculiarly large amount 
 of basic metallic sulphides. According to Svanberg's analysis (Ofversigt af Kongl. 
 
350 APIIN APOPHYLLIC ACID. 
 
 Vatenskaps Acad. Vorhandlingar, iv. 85), its general formula is 7M' J 8.Sb 7 S 3 ; perhaps a 
 mixture of 6M 2 S.Sb 2 S 3 with M a S. It consists chiefly of copper, zinc, silver, iron, and 
 antimony, with only a trace of arsenic. Specific gravity 4*87. 
 
 APIIN. A gelatinous substance extracted by Braconnot (Ann. Ch. Phys. [3] 
 ix. 250), from common parsley (Apium pttroselinuni) by boiling with water. The 
 boiling liquor passed through a cloth becomes on cooling a transparent jelly, like 
 pectic acid. It is washed in cold water, and after drying over the water-bath, is 
 treated with boiling alcohol and ether, which extract from it a certain quantity of 
 chlorophyll. 
 
 Pure apiin is a colourless powder, without odour or taste. It melts at 180 f C. into 
 a yellow liquid, which forms a vitreous mass on cooling. It begins to decompose 
 between 200 and 210 C. It is very sparingly soluble in cold water, but dissolves readily 
 in boiling water, which deposits it on cooling in the form of a jelly. It is soluble 
 in boiling alcohol and insoluble in ether. According to PI ant a and Wallace (Ann. 
 Ch. Pharm. Ixxiv. 262) it contains C^H^O 13 . Its solution in boiling water produces 
 a blood-red colour with ferrous salts : this reaction is extremely delicate, sufficing to 
 indicate the smallest traces of apiin. The aqueous solution, after boiling for a long 
 time, no longer gelatinises on cooling, but deposits nearly white flakes, which appear 
 to consist of C 24 H 28 13 .H 2 0. When apiin is boiled with dilute sulphuric or hy- 
 drochloric acid, the liquor deposits on cooling, white flakes, which appear to contain 
 C'- M H 20 O 9 , that is to say, apiin minus 4 atoms of water. Apiin is dissolved by 
 alkalis and reprecipitated in its original state by acids. When boiled with sul- 
 phuric acid and peroxide of manganese, it yields carbonic, acetic, and formic acids. 
 
 API OS TUBEROSA or Glycine apios (Z.) A leguminous plant from North 
 America, the roots of which have been proposed as a substitute for the potato, and the 
 young seeds for peas. The roots are eaten in Virginia, and are said to have been used 
 by the aborigines of the country. Pay en (Compt. rend, xxviii. 189) gives the follow- 
 ing statement of the composition of the roots, compared with that of the variety of 
 potato called pair ague jau ne. 
 
 Apios. Potato. 
 
 Nitrogenous matter 4'5 1-7 
 
 Fatty matter 0'8 O'l 
 
 Starch, sugar, pectin, &c. . . . . 33'55 21'2 
 
 Cellulose and epidermis . . . .1*3 1'5 
 
 Inorganic matter 2'25 1*1 
 
 Water . 57'8 74-4 
 
 APZRIW or APlTBirJ, An alkaline substance said to be contained in the nut 
 of Cocos nucifcra and Cucos lapidea. (Bizio, J. Chim. med. 1833, 495.) 
 
 APJOHTJITE. See MANGANESE-ALUM. 
 
 APIiITE. A name inappropriately given to a kind of granite, consisting chiefly 
 of a fine-ground mixture of quartz and felspar with only a trace of mica. 
 APX.OIVXZ:. See GARNET. APOGXiUCXC ACID. See GXUCJC ACTD. 
 APROCRENIC ACID. See HuMic ACID. 
 
 APOPH VXiXiXC ACID, C'^'NO 4 . A nitrogenous acid obtained by the de- 
 composition of cotarnine; first prepared by Wo hi er (Ann. Ch. Pharm. i. 24), after- 
 wards more fully examined by Anderson (Edinb. Phil. Trans, xxiii. 347 ; Chem. Soc. 
 Qu. J. v. 257). 
 
 Preparation. 1. Cotarnine is dissolved in nitric acid diluted with twice its volume 
 of water ; strong nitric acid is added ; and the whole is heated to boiling, whereupon 
 abundance of red vapours are evolved. As soon as a small portion of the solution, on 
 being mixed with alcohol and ether, quickly deposits crystals (if no crystals appear 
 the heating must be continued), the whole of the solution is treated in the same way, 
 and the crystals which are deposited after 24 hours, are filtered off and purified by 
 boiling their solution which animal charcoal, and recrystallising. A great excess of 
 nitric acid hinders the precipitation of the apophyllic acid (Anderson). 2. On 
 decomposing chloroplatinate of cotarnine with sulphuretted hydrogen, filtering off 
 the platinum and evaporating the filtrate with hydrate of barium, apophyllate of barium 
 was found in the residue ; and after exti'acting the cotarnine with alcohol, and boiling 
 the residue with dilute sulphuric acid, a yellow solution was obtained which deposited 
 crystals of apophyllic acid after the lapse of several weeks. (Wohler.) 
 
 Apophyllic acid crystallises from a boiling saturated solution on cooling, in rather 
 lonp: anhydrous prisms, which do not effloresce when heated. It reddens litmus strongly 
 and has a weak acid taste (Wohler). Melts at 205 C., and solidifies on cooling, 
 into a crystalline mass. (Anderson.) 
 
APOPHYLLITE 351 
 
 a. Hydrated' apophyllic acid, C^ETNO* . H 2 0, crystallises from a saturated and not 
 boiling solution, in colourless, very sharp rhombic octahedrons the form of which 
 approaches to that of a square-based octahedron. Angles of the base about 88 and 
 92; of the lateral edges, about 106 28', 105 24', and 190. The crystals cleave very 
 readily in a direction parallel to the base, forming faces of pearly lustre, like the 
 crystals of apophyllite (hence the name). These give off their water, amounting to 
 about 9 per cent, at a temperature much below 100 C. (Wohler.) 
 
 Aqueous Apophyllic Acid. Apophyllic acid dissolves slowly and with great difficulty 
 in cold water. It is soluble in sulphuric acid (Anderson); insoluble in alcohol and 
 ether. 
 
 When heated, it melts, chars, and evolves an oily, strongly alkaline liquid, which 
 smells like chinoline ( W 6 h 1 e r). By distillation it yields a neutral oil, as well as a base, 
 which does not become coloured when treated with chloride of lime (Anderson). 
 2. Nitric acid converts it into oxalic acid (Anderson). 
 
 Apophyllates. Nearly all the apophyllates are soluble in water. 
 
 Apophyttate of Ammonium forms small prismatic needles. It is readily soluble in 
 water. 
 
 Apophyllate of Barium is obtained in nodular crystals by digesting the acid with 
 carbonate of barium and adding alcohol to the solution. (Anderson.) 
 
 Apophyttate of Ammonium does not precipitate lead-salts. (Wohler.) 
 
 Apophyttate of Silver, C 8 H 6 AgN0 4 , is obtained by digesting apophyllic acid with 
 moist carbonate of silver and precipitating the solution with alcohol and ether. It 
 forms a crystalline powder, which burns slowly when heated, leaving a residue of 
 metallic silver. It is easily soluble in water, insoluble in alcohol and ether (Ander- 
 son). On mixing a solution of apophyllate of ammonium with nitrate of silver, 
 a double salt, consisting of apophyllate and nitrate of silver, C 9 H 6 AgN0 4 .NO s Ag, is 
 deposited after a while in small crystalline stars, which soon increase to zeolitic 
 groups of fine needles. The salt explodes violently when heated, like oxalate of silver. 
 It is slightly soluble in water. 
 
 APOPH"if SiX.ITE. Ichthyophthalmite, Fish-eye stone. A silicate of calcium and 
 potassium, also containing fluorine, which is found both massive and crystallised. 
 The crystals belong to the dimetric system. The most usual form is oo P oo . P, also 
 with OP. Cleavage perfect, parallel to OP, imperfect parallel to oo P oo . The massive 
 variety has a laminated structure. Specific gravity 2*3 to 2-4. Hardness about that 
 of apatite, or generally rather less. The finest varieties are transparent and colour- 
 less, or sometimes tinged with rose colour; translucent crystals are also found, or 
 opaque in the mass, translucent only at the edges, and white, reddish-white, or flesh- 
 coloured. External lustre splendent and peculiar; internal lustre glistening and 
 pearly. The transparent crystals exhibit, according to Brewster, a peculiar optical 
 character, which shows that each individual crystal is an aggregate of several pieces 
 symmetrically arranged. In some places (especially at Aussig in Bohemia) a variety 
 called albin is found, consisting of opaque crystals of peculiar form. Apophyllite, heated 
 before the blowpipe, exfoliates (hence its name, from a.Tro<f>v\Xi&ii>\ then froths, and 
 melts into an opaque bead. It is easily decomposed by strong hydrochloric acid, with 
 separation of gelatinous silica. The filtrate, supersaturated with ammonia, yields 
 a precipitate of fluoride of calcium. 
 
 The composition of apophyllite, as determined by analysis, is as follows : 
 
 Berzelius. Stromeyer. 
 
 Silica 52-13 51-86 
 
 Potash .... 5-27 5-31 
 
 Lime (including CaF) . . 25-53 25-22 
 
 Water 16-20 16-91 
 
 99-13 99-30 100-73 
 
 From these results, L. G-melin (Handb. iii. 394) deduces the formula 
 + 6(<?a0.2&'0 2 ) + CaO.SiO* + CaF + 16HO*, or 15Si0 2 .7Ca 2 O.K 2 + 2CaF + 16H 2 0.f 
 Simpler formulae may be obtained, if we suppose the fluorine to take the place of 
 part of the oxygen in equivalent proportion. Berzelius gives the formula KO.2^10 3 
 - 8(CaO.i0 3 )$ + 16HO, which, if M denote a monatomic radicle, may be reduced to 
 WSii0 3 .9MO.l6HO. The analytical results may, however, be equally well represented 
 by the general formula 9 5i s . 8M0.15HO; and, assuming that BHO may replace 
 1MO (see ISOMORPHISM, POLYMERIC), this formula may be reduced to 9^i0 3 .13Jf 0, $ 
 or 27Si0 2 .26M 2 0. 
 
 * Si = U ; = 8. t Si = 28 ; O = 1G. J j = 21 - 5 ; = 8. 
 
352 APORETIN ARABIN. 
 
 APOUETITT. A resin obtained by dissolving in alcohol that portion of the 
 alcoholic extract of rhubarb which is insoluble in water, precipitating by ether, and 
 again treating the precipitate with alcohol, the aporetin then remaining uudissolved 
 (Schlossberger and Dopping, Ann. Ch. Pharm. i. 219). Treated with concen- 
 trated nitric acid, it yields a yellow substance, which appears to be chrysammic acid, 
 together with oxalic acid and an acid which produces a brown-red colouring with 
 alkulis. (De la Rue and Miiller, Chem. Soc. Qu. J. x. 298.) 
 
 APOSEPXDIxr. Kdsoxyd. A product of the putrefaction of the so-called 
 protein-compounds, discovered by Proust, but since shown by Mulder and others to be 
 merely impure leucine. 
 
 APOTHEIVI. A term applied by Berzelius to the insoluble brown deposit which 
 forms in vegetable extracts when exposed to the air. It is not a definite compound, 
 but a mixture of several substances in a state of decomposition, and therefore of very 
 variable constitution. (See DECAY and PUTREFACTION.) 
 
 APPXiES. A comparison of various sorts of apples and pears, with regard to 
 specific gravity and amount of water and acid in the juice, has been made bySchulze 
 (J. pr. Chem. Ixii. 207). The results vary greatly according to season, climate, and 
 soil; but the general conclusions are as follows: The specific gravity of the fresh 
 fruit varies from 072 to 0-91. The fruits contain between 13 and 21 per cent, of dry 
 substance, of specific gravity above 1'4. The juice of 20 kinds of apples had a specific 
 gravity between 1'020 and 1-027; in two varieties only, it was found to be between 
 1-033 and T037. The acid in the juice, estimated as tartaric acid, amounted to 
 between 0-48 and 1'13 per cent. In Wurtemberg. the specific gravity of the juice of 
 apples and pears rises in warm seasons above 1-080, and even approaches T090, the 
 amount of free acid, estimated as tartaric acid, varying from 0'4 to 1'2 per cent., and 
 that of sugar from 4 to 10 per cent. 
 
 APPLE-TREE. (Pyrus Mains.') The ash of the branch of an apple-tree con- 
 tained, after deducting the carbonic acid, in 100 pts. : 19'24 potash; 0'45 soda; 
 63-60 lime; 7*46 magnesia ; 2'41 ferric phosphate ; 4 - 15 phosphoric acid; 0-45 chlo- 
 ride of sodium; 0'93 bulpliuric acid; and 1*31 silica. (Fresenius, Handw. d. Chem. 
 2 te Aufl. i. 171.) 
 
 MalviJe. A yellowish oil formed in apples when kept. It is 
 lighter than water, has a yellowish-grey colour, a sharp and harsh taste, boils at 
 190C., and distils completely; burns with a slightly fuliginous flame; dissolves 
 sparingly in water, but readily in alcohol and ether. Contains 64'15 per cent, carbon, 
 20'65 hydrogen, and 15*20 oxygen. Forms a crystalline compound with hydrochloric 
 acid, but is decomposed by chlorine. (Handw. d. Chem. 2 te Aufl. i. 172.) 
 
 APPXiE-OIXi ( ARTIFICIAL ). This name is given to a solution of valerate 
 of amyl in 6 or 7 parts of alcohol, which has the smell of apples, and is used as a 
 perfume. (Hofmann, Ann. Ch. Pharm. Ixxxi. 87.) 
 
 APYRXir. See APIRIN. 
 
 APYRXTE. Siberite, Rubellite, Red tourmaline. See TOURMALINE. 
 
 AQUA FORTXS. This name is given to a weak and impure nitric acid commonly 
 used in the arts. It is distinguished by the terms double and single, the single having 
 only half the strength of the other. The artists who use these acids call the more 
 concentrated acid, which is much stronger even than the double aqua fortis, spirit of 
 nitre. (See NITRIC ACID.) 
 
 AQUAMARINE. See BERYL. 
 
 AQUA-RECrXA or REG-ZS. A mixture of nitric and hydrochloric acid, so 
 called from its property of dissolving the noble metals, gold and platinum. (See 
 
 NlTRO-HYDROCHLORIC AciD). 
 
 AQTTA-VIT.2E. Ardent spirit of the first distillation has been distinguished by 
 this name in commerce. The distillers of malt and molasses spirits call it low wines. 
 
 AQUXX.A AX.BA, IKXTIGATA, CCEX.ESTIS, 1KERCTTRXX. An old name 
 for subchloride of mercury ; also mercurius dulcis, or mild muriate of mercury. 
 
 ARABIC (G-UTO). This gum exudes spontaneously from several species of 
 acacia (Acacia vura, A. arabica) &c. It was formerly imported into Europe from 
 Egypt and Arabia, but is now obtained chiefly from Senegal. The co-ir.-irr and 
 cheaper varieties mostly used by calico printers and other manufacturers are known 
 by the name of gum-senegal. (See GUM.) 
 
 ARABXN*. The principal constituent of gum arabic, in which, according to 
 
ARACHIDIC ACID-ARACHIS. 353 
 
 Neubauer (Ann. Ch. Pharm. cii. 105), it exists in combination with lime, magnesia 
 and potash. By treating the gum with hydrochloric acid and alcohol, these compounds 
 are decomposed, and the arabin is separated in the form of a gum, which exhibits the 
 properties of an acid. In the moist state, it dissolves readily in cold water, forming a 
 gummy solution, from which it is precipitated by alcohol. After drying at 100 C. it no 
 longer dissolves in cold water, but merely swells up to a gelatinous mass. Dried at 
 100 C. it has the composition C I2 H* 2 U , ^ of the hydrogen being replaceable by 
 metals. 
 
 ARACHXDIC ACID, C^H^O 2 = -g 0. Produced by the saponification 
 
 of oil of earth-nut (Arachis liypogaa]. The oil is saponified with soda ; the mixture of 
 fatty acids separated from the soap by hydrochloric acid, is macerated with five or six 
 times its bulk of cold alcohol to remove the volatile acids ; the insoluble portions 
 are pressed and dissolved in alcohol; and the solution, heated nearly to the boiling 
 point, is mixed with such a quantity of acetic acid, that on adding an excess of alco- 
 holic acetate of lead, no precipitation takes place while the liquid remains hot. The 
 crystals which separate after the liquid has remained in the cold for forty-eight hours, 
 are separated from the liquid and mixed with alcohol and hydrochloric acid ; the 
 resulting ethers of the fatty acids, after being filtered off from the chloride of lead 
 and freed from part of the alcohol by evaporation, are decomposed by boiling with soda-ley 
 after the alcohol has been completely expelled ; the resulting soda-soap is decomposed 
 by hydrochloric acid : and the mixture of fatty acids thus separated, is again dissolved 
 in alcohol, and fractionally precipitated with alcoholic acetate of magnesium. The 
 portions first precipitated contain arachidic acid, which after several crystallisations is 
 obtained pure. 
 
 Arachidic acid crystallises in very small shining scales ; melts at 75 C., and solidifies 
 again at 7 3 - 5, forming a radiated mass, which after a while assumes the appearance 
 of porcelain. It is but very slightly soluble in cold alcohol of ordinary strength, but 
 dissolves easily in boiling absolute alcohol and in ether. (A. Grossman n, Ann. Ch. 
 Pharm. Ixxxix. 1.) 
 
 The acid is monobasic, belonging in fact to the series of fatty acids, C"^" - 'O 2 .!!. 
 The ammonium, potassium, and sodium salts, are soluble in water, the rest insoluble 
 or sparingly soluble in water, but soluble in boiling alcohol. The silver-salt, 
 C^H^O^Ag, is a white precipitate which separates from boiling alcohol in slightly 
 lustrous prisms, not altered by exposure to light. (Grossmann and Sch even, Ann. 
 Ch. Pharm. xcvii. 257.) 
 
 Arachidate of Ethyl, C^H^O^C 2 !! 5 , obtained by passing hydrochloric acid gas 
 through an alcoholic solution of the acid at 80 or 90 C., is a crystalline, slightly 
 tenacious mass, which melts at 52'5, and solidifies at 51. (Grossmann.) 
 
 Arachamide, (C'^H^O^N^N, is obtained by leaving earth-nut oil for several 
 weeks in contact with ammonia. It forms prisms grouped in stars, insoluble in water, 
 dissolving with tolerable facility in boiling alcohol, melting at 98 or 99 C. When 
 fused with hydrate of potassium, it gives off ammonia. 
 
 AracMn, or Arachidate of Glt/ceryl, is obtained by heating equal parts of arachidin 
 acid and syrupy glycerin to 210 C. in a sealed tube. It is a lustrous fatty substance 
 which melts at 70 C., and solidifies in a crystalline mass when slowly cooled. It dis- 
 Bolves^ sparingly in alcohol of 90 per cent., more freely in absolute alcohol, and still 
 more in ether. It gave by analysis 76-2 per cent, carbon, and 12*6 hydrogen ; whereas 
 the formula of triarachidate of glyceryl, C 3 H S 3 .(C 20 H S9 O) 3 , requires 77'62 C and 12'6 H 
 (Grossmann and Scheven). Berthelot (Ann. Ch. Phys. [3] xlvii.355) regards the 
 product obtained by Grossmann and Scheven as a mixture of diarachin with free 
 arachidic acid. He prepares the pure neutral arachins by melting in a flask the crude 
 product obtained by heating glycerin with arachidic acid, then adding slaked lime to 
 neutralise the free acids, digesting with ether for fifteen minutes, and afterwards 
 boiling with ether, which dissolves the neutral fat and leaves the lime-soap undissolved. 
 The ethereal solution when evaporated, leaves the neutral fat, which, if quite free 
 from adhering fatty acids, should form with boiling alcohol a solution which does not 
 redden litmus. In this manner Berthelot has obtained the three neutral arachins, 
 corresponding to the acetins, viz. monoarachin, C 3 H 5 3 .C 2e H 39 O.H 2 , diarachin 
 C 3 H 5 3 .(C 20 H 39 0) 2 .H, and triarachin, C 3 H 5 3 .(C 20 H 39 0) 3 . 
 
 ARACHXS HYPOGIEA. Earth-nut. A leguminous creeping plant, indi- 
 genous to India and the coasts of South Africa and South America, and cultivated in 
 North America and in the south of Europe. The flower-bearing stems exhibit, as 
 soon as the fruit begins to form, a tendency to bury themselves in the soil, those 
 which remain above ground bearing little or no fruit. Hence in the cultivation of the 
 plant, the main point to be attended to is to cover up with earth all the flower-bearing 
 
 VOL. I. A A 
 
354 ARACHYL ARBUTIN. 
 
 stems as soon as the flowers fade. The seeds contain about half their weight of faf; 
 oil, earth-nut oil (huile d"arackide, huile de pistache de terre, Erdnuss-ol), which is 
 extracted from them by pressure. The cold-pressed oil is nearly colourless, has a 
 faint agreeable odour, and may be used for culinary purposes instead of olive oil, 
 only it becomes rancid more quickly. The warm-pressed oil is coloured, and has 
 a disagreeable taste and smell. The cold-pressed oil has a density of 0'916 at 50 C.; 
 and solidifies at 3 C. When it is exposed for some time to a temperature of + 3C. 
 a solid fat resembling stearin separates from it. It dissolves but sparingly in alcohol, 
 more readily in ether and essential oils. It saponifies slowly when boiled with caustic 
 soda, yielding a hard, white, odourless soap, which is manufactured in France, and to 
 some extent also in Germany. This soap, when decomposed by the stronger acids, 
 yields two peculiar fat-acids, viz. arachidic acid, C 20 H 40 O 2 , belonging to the series 
 OH 2n 2 , and hypogaeic acid, C 16 H S0 2 , belonging to the oleic acid series, OH 2n - 2 2 
 besides a large quantity of palmitic acid. The oil consists therefore of arachin, hypo- 
 gsein, and palmitin. 
 
 ARACHYXi. C 20 H 39 0. The hypothetical radicle of arachidic acid. 
 
 AH.ZEO1VEETER. See HYDROMETER. 
 
 (from &pa.ios, rare and eVos, guest). A variety of vanadate of 
 lead, in which a considerable portion of the lead is replaced by zinc, giving the 
 formula V0 3 (Pb; Zn) 3 . Von Kobell found 487 per cent, oxide of lead, and 16 ; 3 per 
 cent, oxide of zinc. The mineral, which was formerly mistaken for chromate of lead, 
 is found in clefts of a bed of sandstone, at Dahn in the Eheinpfalz. It forms 
 botryoidal crystalline masses, exhibiting on the fracture traces of radiating structure. 
 Colour, dark red, inclining to brown ; slightly translucent. Streak, light yellow. 
 Hardness 3. Melts quickly before the blowpipe, with intumescence. The powder 
 is easily decomposed by heating with hydrochloric acid. (See Kobell, J. pr. Chem. 
 ii. 496.) 
 
 A-g.soi.-A-ss.EA RESIN. This resin is the produce of the Canarium album, 
 a tree belonging to the natural order Terebinthaeece, which grows in the Phillipine 
 Islands ; the resin, which is used by the natives for caulking their canoes, is greyish 
 yellow, soft, glutinous, and has a strong agreeable odour. According to Bon a st re 
 (J. Pharm. x. 199) it contains in 100 pts. 6T29 pts. of resin, very soluble in alcohol ; 
 25-00 of resin, sparingly soluble in alcohol; 6-25 essential oil; 0'52 free acid; 0-52 
 bitter extractive matter; 6-42 woody and earthy impurities. Baup (Ann. Ch. Phys. 
 [3] -rim'- 108) has obtained from it four different crystallisable substances, viz. 
 
 Amyrin. Insoluble in water, sparingly soluble in cold, easily in hot alcohol, easily 
 also in ether, whence it crystallises in satiny fibres, having a strong lustre. Melts at 
 174 C. Contains, according to Dumas, 85-3 per cent, carbon and 117 hydrogen, and 
 is perhaps identical with crystallised elemi-resin. 
 
 Breidin. Crystallises in transparent rhomboidal prisms of 102 and 78, terminated 
 by four sided pyramids. Dissolves in 260 pts. of water at 10 C. much more abun- 
 dantly in hot water; easily in alcohol, sparingly in ether,. The crystals become 
 opaque at a gentle heat, melt at a temperature a little above that of boiling water, 
 and sublime undecomposcd at a higher temperature, yielding a slightly pungent 
 vapour which excites coughing. 
 
 Brein. Insoluble in water, soluble in 70 pts. of 85 per cent, alcohol at 20 C.; more 
 soluble in absolute alcohol ; very soluble in ether. When slowly crystallised from an 
 alcoholic solution, it forms transparent rhomboi'dal prisms of about 70 and 110, 
 terminated by dihedral summits whose faces meet at about 80. By rapid cooling 
 acicular crystals are formed. Melts at 187 C. Neutral. 
 
 Bryo'idin. Crystallises from water in white silky filaments. Has a slightly bitter 
 and burning taste, and when heated gives off a vapour which excites coughing. Melts 
 at 135 C., begins to volatilise before melting, and sublimes in colourless needles. Spar- 
 ingly soluble in cold, much more in hot water, very easily in alcohol and ether. The 
 aqueous solution is neutral to test-paper, but precipitates acetate and subacetate 
 of lead. 
 
 ARBOR XtXAXTJE, ARBOR 1KARTXS, ARC OR SATURNTX, &.C. These 
 names are applied to the arborescent metallic precipitates formed by the slow reduction 
 of one metal in solution by another, e.g. lead by zinc. 
 
 ARBUTXXir. A crystalline substance discovered by Kawalier (Ann. Ch. Pharm. 
 Ixxxi. 241 ; Ixxxiv. 356) in the leaves of the red bear-berry (Arctostaphylos Uva 
 Ursi). The aqueous infusion of the leaves forms with neutral acetate of lead a 
 yellow precipitate containing gallic acid; the filtered liquid freed from excess of 
 lead by hydrosulphuric acid, and then concentrated to the consistence of a syrup, 
 deposits crystals of arbutin, which may be pimficd by pressure, solution in boiling 
 
ARC ANITE ARCHIL. 356 
 
 water, and treatment with animal charcoal. Arbutin forms groups of coloxirless 
 bitter crystals, which are soluble in water, alcohol, and ether ; the solutions are neutral 
 to test-paper. 
 
 When heated it melts and gives off water of crytallisation. Its aqueous solution 
 does not form any precipitate with ferric salts, or with acetate or subacetate of lead. 
 
 A solution of arbutin mixed with emulsin (extracted from sweet-almonds), and left 
 for some days in a warm place, acquires a reddish tint, and leaves when evaporated 
 over the water-bath, a reddish brown residue, from which ether extracts arctuvin, 
 and leaves a quantity of insoluble saccharine matters. This decomposition of arbutin 
 is represented, according to Kawalier, by the equation : 
 
 Arbutin. Arctuvin. Glucose. 
 
 but according to Gerhardt, by the equation 
 
 C.8JJ22Q10 = C 12 H 10 0' + C"H 12 6 
 
 Arbutin. Arctuvin. Glucose. 
 
 Kawalier's analysis of arbutin gives 52'4 per cent, carbon, and 6*1 hydrogen. His 
 formula requires 52*4 C and 6-0 H ; Gerhardt' s, 54'2 C and 5'5 H. (Gerhardt, Traite, 
 iv. 266.) 
 
 ARCASIXTX:. See GLASERITE. 
 
 ARCXXXXi, ORCHIIi, or ORSEIZiXiE. A fine purple dye obtained from various 
 species of lichen. There are two varieties, called in France orsciUe de mer and orseille 
 de terre. The former is obtained from various lichen's of the genus Rocella growing on 
 the rocky coasts of the Azores, the Canary and Cape de Verd isles, also of the Cape 
 of Good Hope, Madeira, Corsica, Sardinia, &c. ; the latter from Varlolaria orcina, from 
 Auvergne, Variolaria dcalbata, from the Pyrenees, Lccanora tartarea, from Sweden, and 
 others. None of these lichens contain the colouring matter ready formed, but they 
 contain certain colourless acids, erytkric, lecanoric acid, &c., which are susceptible 
 of transformation into a colourless neutral body. called orcin (q. v.) ; and this, when 
 acted upon by the air and by ammonia, changes into a purple substance called 
 orcein, which is the colouring principle of archil. 
 
 To prepare archil, the lichens, after being ground between stones, are rubbed up to 
 a thin paste with water and putrefied urine or carbonate of ammonium, and left to 
 ferment, with addition of quick lime, a small quantity of alum or arsenious acid being 
 sometimes added, perhaps, to prevent the fermentation from going too far. In a week, 
 a violet colour is obtained, which becomes brighter in a few days longer. When 
 carbonate of potassium or sodium is added to the lichens as well as ammonia, a 
 different change takes place, and a blue colouring matter called Litmus is obtained, 
 which is never produced by the action of ammonia alone. (See LITMUS.) 
 
 Dyers rarely employ archil by itself, on account of its dearness, and the perishable- 
 ness of its beauty. The chief use they make of it is for giving a bloom to other 
 colours, as pinks, &c. This is effected by passing the dyed cloth or silk through hot 
 water slightly impregnated with the archil. The bloom thus communicated soon 
 decays upon exposure to the air. The addition of a little solution of tin gives a 
 durable dye, the colour of the archil being at the same time changed toward a scarlet, 
 and becoming more permanent in proportion as it recedes the more from the natural 
 tint. 
 
 Prepared archil very readily gives out its colour to water and to alcohol ; it is the 
 substance principally made use of for colouring the spirits of thermometers. As 
 exposure to the air destroys its colour upon cloth, so does the exclusion of the 
 air produce a like effect in these hermetically sealed tubes, the spirits of large ther- 
 mometers becoming in a few years colourless. The Abbe Nollet observes (in the 
 Memoirs of the Academic des Sciences for the year 1742) that the colourless spirit, 
 upon breaking the tube, soon resumes its colour, and this for a number of times succes- 
 sively ; that a watery tincture of archil, included in the tubes of thermometers, lost its 
 colour in three days ; and that in an open deep vessel it became colourless at the 
 bottom, while the upper retained its colour. 
 
 A solution of archil in water, applied on cold marble, stains it of a beautiful violet 
 or purplish-blue colour, far more durable than the colour which it communicates to 
 other bodies. M. du Fay says he has seen pieces of marble stained with it, which in 
 two years had suffered no sensible change. It sinks deep into the marble, sometimes 
 above an inch, and at the same time spreads upon the surface, unless the edges be 
 bounded by wax or some similar eubstance. It seems to make the marble somewhat 
 more brittle. 
 
 There is a considerable consumption of a variety of archil manufactured in Glasgow. 
 It is much esteemed, and sold by the name of cudbear. It affords very beautiful 
 
 AA 2 
 
356 ARCTIZITE ARG YRITES. 
 
 colours on silks, of various shades, from pink and crimson to a bright mazarine bine, 
 which are said to be very permanent U. (See Ure' s Dictionary of Arts, Manufactures, 
 and Mines, i. 175.) 
 
 ARCTIZITE. See WERNERITE. 
 
 ARCTOSTAPHTXiOS TJVA TTRSI. The bear-berry. An ericaceous plant 
 which grows wild in the mountainous parts of England and Scotland, and in the north of 
 Europe. It possesses strongly astringent properties. The leaves boiled with water yield 
 a liquid which contains tannic acid and a large quantity of gallic acid, and may therefore 
 be used for making ink. The same decoction contains, according to Kawalier, (Ann. 
 Ch. Pharm. Ixxx. 356) arbutin, sugar, ericolin, a resinous substance, wax, fat, chloro- 
 phyll, vegetable fibre, and a body resembling emulsin, which has the power of inducing 
 the transformation of arbutin. The resin may be separated from the mother-liquor of 
 the preparation of arbutin, by heating it with hydrochloric acid. It is brittle, nearly 
 
 black, dark brown after trituration, and is said to consist of C^H^O ^, perhaps rather 
 C^IT'O 8 . Besides these substances, H. Trommsdorff (Chem. Gaz. 1853, p. 61) also 
 found in the leaves another crystallisable substance which could be extracted by ether, 
 viz. ursonc. 
 
 ARCTUVTN is deposited by evaporating the ethereal solution of the brown 
 residue obtained by the decomposition of arbutin (p. 354), in colourless crystals, 
 which are purified by recrystallisation from water, alcohol, and ether, with the aid of 
 animal charcoal. It forms long prisms, which are bitter, fusible, and may be sublimed 
 when cautiously heated. It contains, according to Kawalier' s analysis, 64-4 C and 
 5-6H. The formula C 20 H-0 7 requires 64*50 and 5-4 H. Gerhardt's formula, 
 C 12 H 10 4 , requires 65'4 C and 5'4 H. If sesquichloride of iron be added, drop by drop, 
 to an aqueous solution of arctuvin, the mixture assumes a bluish tint, gradually 
 changing to green. With a solution of subacetate of lead containing a little ammonia, 
 arctuvin forms a white precipitate, which soon turns brown. Arctuvin moistened 
 with ammonia and exposed to the air gradually forms a black substance, which 
 Kawalier calls arctuvein ; it contains 35'9 C, 3*0 H, 12'5 N, and 48'6 0. (Gerhardt, 
 Traite iv. 266.) 
 
 ARECA NUTS, the fruit of the areca palm (Areca catechu, L.}, contain, as 
 their chief constituents, catechu, a variety of tannic acid, and gallic acid, together 
 with acetate of ammonium, fats, oil, gum, nitrogenous substances, and a dye called 
 areca-red, which is of a brown colour, without taste or smell, insoluble in cold water and 
 in ether, soluble in boiling water and alkaline liquids, whence it may be precipitated 
 by acids. Boiled with nitric acid, it yields oxalic acid. (Morin, J. Pharm. viii. 449.) 
 
 ARENDAX.XTE. See EFIDOTE. 
 
 ARETHASE, a name given by Laurent to a product of the decomposition of 
 chloride of cacodyl by alcoholic potash. (See ARSENIC-RADICLES, ORGANIC.) 
 
 ARPWEDSONXTE. A ferruginous variety of hornblende. Colour black. 
 Cleavage-faces much more brilliant than those of hornblende, which scratches it. 
 Specific gravity 3 -44. Melts even in the flame of a candle ; boils up strongly before 
 the blowpipe, and yields a black magnetic globule. Not soluble in acids or in caustic 
 potash. Its composition may be represented by the general formula Si 6 M'0 17 = 
 5M 2 0.6Si0 2 . A specimen from Greenland, analysed by Kobell (J. pr. Chem. xiii. 3) 
 yielded results agreeing nearly with the formula (15Fe 2 0.4Na 2 O.Ca 2 0).24Si0 2 . 
 
 SiO 2 Fe 2 O NaK) Ca 2 Mg'O Mn 2 A1 4 3 Cl 
 
 Analysis . . 49'27 36-12 8'00 1-50 0-42 0-62 2'00 0'24 = 98-17. 
 Calculation . . 52'33 36-93 877 1'97 ........ = lOO'OO. 
 
 or ARGOI. The commercial name of crude tartar in the state in 
 which it is taken from the inside of wine-casks. 
 
 ARGENT AN. Syn. of Nickel-silver or German silver. See NICKEL. 
 
 ARGENT AXKAXONXUlftK. A metallic ammonium-radicle (p. 198), containing 
 1 at. silver in place of hydrogen. Its oxide (NH 3 Ag) 2 is commonly called fulminat- 
 ing silver. (See SILVER.) 
 
 ARGENTINE. A schiefer-spar mixed with silica, found at Southampton and 
 Williamsburgh, in Massachussets. (See CALCSPAR.) 
 
 ARGENTINE FLOWERS OF ANTIMONY. An old name of tctroxide of 
 antimony, or antimonate of antimony (p. 324). 
 
 ARGENTITE or ARGYROSE. Syn. of SILVER-GLANCE. 
 
 ARGXXiXiACEOUS EARTH, See ALUMINA and CLAY. 
 
 ARG7RXTE8. See LEAD-OXIPK. ARGYROSE. See SILVER-GLANCE. 
 
ARICINE ARNICA. 357 
 
 &R1CINE. C 2S H 2fi N 2 4 (Cinckovatine, Cusconinc, Quinovine}.A.n alkaloid, dis- 
 covered in white cinchona bark from Arica, by Pelletier and Corriol (J. Pharm. 
 [2] xv. 575). Manzini (J. Pharm. [3] ii. 95) afterwards, found in a fibrous white 
 cinchona from Jaen, an alkaloid which he called cinckovatinc, but which has been 
 shown by Winckler (Buchner's Kepert, d. Pharm. [2] xxxi. 294; xlii. 25 and 231 ; 
 ibid. [3] i. 11) to be identical with aricine, 
 
 Aricine is extracted from the cinchona bark in the same manner as quinine (q. v.\ 
 viz. by boiling the bark with acidulated water, treating the liquor with lime, and 
 digesting the lime-precipitate in alcohol. The solution, filtered at the boiling heat, 
 yields a very dark-coloured liquid, which, after a while, deposits the greater part of 
 the aricine in crystals. An additional quantity may be obtained from the mother- 
 liquor by expelling the alcohol by distillation, treating the residue with a slight excess 
 of hydrochloric acid, separating the greater part of the colouring matter by means of 
 a saturated solution of common salt, then precipitating the aricine by ammonia, dis- 
 solving the precipitate in alcohol, decolorising with animal charcoal, and crystallising. 
 
 Aricine forms white prismatic crystals, more elongated than those of cinchonine ; 
 they are inodorous, and have a bitter taste, which, however, does not show itself for 
 some time, on account of the sparing solubility of the alkaloid. It dissolves easily in 
 alcohol, especially when warm, less readily in ether. The solution blues reddened 
 litmus, and turns syrup of violets green. The crystals, which are anhydrous, melt at 
 188 C,, forming a brownish liquid, which blackens at a higher temperature, yielding 
 fetid empyreumatic products. Aricine dissolves with decomposition in strong nitric 
 acid, forming a deep green solution : this is a very characteristic reaction. 
 
 The salts of aricine are, for the most part, easily soluble and crystallisable. They 
 are obtained by dissolving aricine in dilute acids; the solutions are precipitated 
 by alkalis. The add sulphate, C 28 H 26 ]S^0 4 .S0 4 H 2 , crystallises in flattened needlea 
 (Pelletier), which are anhydrous (Manzini). The neutral sulphate does not crys- 
 tallise from solution in water, but forms a gelatinous mass, which dries up to a 
 horny substance (Pelletier, Ann, Ch. Phys. [2] 1L 185). The platinum-salt, 
 C 23 H* G N 2 4 .HCl.Ptl 2 , is soluble in alcohol, and is deposited from the solution by 
 spontaneous evaporation in crystalline plates. 
 
 ARISTOI.OCHIA CLEIWCATITIS. Birthwort. The root of this plant, 
 which has a sharp bitter taste, and was formerly much used in medicine, has been ex- 
 amined by several chemists : but the results hitherto obtained are not very definite. 
 When distilled with water, it yields about 0-004 of an essential oil of specific gravity 
 0-903, and said by Walz to be composed of C U H 8 8 . A volatile acid, aristolochic acid also 
 passes over, the barium-salt of which contains, according to Walz, C 8 IIBa 2 9 . From 
 the aqueous extract of the root, Walz obtained an impure bitter compound, clemati- 
 dine, C 9 H 5 6 , which is perhaps identical with the aristolochine obtained by Chevalier 
 from Aristolochia serpentaria. Frickinger obtained from the root a bitter uncrys- 
 tallisable body, and also a yellow crystalline substance, aristolochia-yellow, perhaps 
 identical with aristolochine or clematidine. The root also contains a resin soluble in 
 alcohol and ether. The inorganic constituents of the root are : potash 10'3, soda 4*2, 
 chloride of sodium 8'6, lime 9'1, magnesia 3'0, phosphoric acid (PO 4 ) 14-2, sulphuric 
 acid (SO 3 ) 1*4, sesquioxide of iron 3'1, silica 4*5, sand, charcoal, and carbonic acid 
 4-35. (Winckler, Jahrb. pr, Pharm. xix. 71; Frickinger, Buchn. Kepert. [3] vii. 
 1 ; Walz, Jahrb. pr. Pharm. xxiv. 65 ; xxvL 65.) 
 
 ARISTOLOCHIA SERPEMTTARIA. The root of this plant, which had 
 once a great repute "in medicine, is now nearly fallen into disuse. Chevalier states 
 that the active principle of it is a yellow bitter substance, which he calls aristolochine. 
 The root also contains an essential oil, resins, gum, &c. 
 
 ARKANSITE. See BROOKITE. 
 
 ARXX. See ARSA. 
 
 ARK.OSC. A fclspathic sandstone, often having a porphyritic structure, found 
 near Poiyin in the Vosges. According to Delesse (Arch. d. Sc. Phys. et Nat. de 
 Geneve vii. 177) it has been metamorphosed in the humid way, by taking up the 
 constituents of felspar and hyalite, and gradually transformed into the Vosges sand- 
 stone above and granite below. 
 
 STOOTE. Lapis Armenius, Armenite.An old name for a mixture 
 
 of earthy azure copper and limestone, sometimes mixed with copper or iron pyrites ; 
 or for quartz coloured blue by azure copper. 
 
 ARNICA, Oil. OP. Both the roots and the flowers of Arnica montana contain 
 volatile oils. The oil is obtained from the flowers has a yellow to brownish green 
 colour, dissolves in 100 pts. of alcohol, of specific gravity 0-85, becoming turbid and 
 flocculent, and in 10 to 60 pts. of absolute alcohol, and forms a solid- resin, whoa 
 
 A A 3 
 
358 ARNICINE AREAGONITE. 
 
 treated with nitric acid. The oil from the roots has a specific gravity of - 98 to 0-99, 
 and a wine-yellow to brownish yellow colour ; dissolves in 2 pts. of alcohol of specific 
 gravity 0'85, and in all proportions of absolute alcohol, and becomes viscid when 
 treated with nitric acid. Both oils have a slight acid reaction. (Zeller, " Studien 
 .iiber atherische Oele," Landau, 1850.) 
 
 ARNZCXaiXi. A bitter principle in the flowers of the Arnica montana. 
 
 ARPIDE1.ITB. See SPHENE. 
 
 ARQUERXTE. A silver amalgam from the mines of Arqueros in Coquimbo, Chili. 
 
 ARRACK. A spirit obtained by fermenting infusion of rice. In Ceylon it is ob- 
 tained from cocoa-nut toddy (palm wine). 
 
 ARRAGOXTXTE. Rhombic Carbonate of Lime. This mineral, which derives its 
 name from the locality where it was first found, viz. in Arragon, occurs sometimes in 
 regular crystals, sometimes in fibrous or radiated crystalline masses, sometimes as a 
 deposit or sinter from hot calcareous springs. 
 
 The crystals belong to the dimetric, rhombic, or right prismatic system, and are 
 derived from a right rhombic prism with angles of 116 16' and 63 44', exhibiting 
 two directions of distinct cleavage parallel to the faces of this prism. Twin-crystals 
 also frequently occur, likewise globular, reniform, and botryoidal masses, sometimes 
 columnar, composed of straight or divergent fibres. 
 
 The crystals of arragonite are seldom colourless, mostly exhibiting a variety of 
 colours ; yellowish, greenish, reddish, brown, grey, &c. They have a vitreous lustre, 
 and the powder exhibits phosphorescence on a plate of hot iron. Specific gravity in 
 the pulverulent state, and when free from air, from 2'92 to 3'8 ; larger masses have 
 occasionally a specific gravity as low as 277. Hardness about from 3*5 to 4. 
 
 Crystals of arragonite are found in various localities; in clay and gypsum in 
 Arragon ; in clefts and cavities of the newer volcanic rocks, especially of basalt, as at 
 Bilin in Bohemia, in Hungary, Scotland, the Feroe Isles, &c. ; also in the dolerite on 
 the Kaiserstuhl in the Breisgau ; in gneiss and syonite near Dresden and in North 
 America ; in the lava of Etna and Vesuvius, &c. Radiated arragonite, which forms 
 crude masses having a radiated structure, is found chiefly on the Kaiserstuhl in the 
 Breisgau, at Gergovie in Auvergne, and in Scotland. Fibrous arragonite, iron-bloom, 
 or jlosferri, occurs in globular, kidney-shaped or stalactilic mass, having a fibrous or 
 laminar texture, and a mother-of-pearl lustre. It is found in veins of iron ore in 
 Carinthia and Styria, Hungary and Transylvania. Sprudelstein, a fibrous variety of 
 carbonate of calcium deposited from hot calcareous springs, contains both arragonito 
 and calcspar. Mountain milk, Bock milk (Bergmilch, Chaux carbonatee pulverulentc), 
 is, according to H. Rose, arragonite mixed with chalk ; it occurs in thick, spongy, 
 globular, or kidney-shaped masses, or as a deposit in limestone cavities in Wurtem- 
 berg, Switzerland, Bohemia, and other localities. Specific gravity 2'72 to 2'82. It 
 contains traces of organic matter, and leaves a small quantity of charcoal when ignited 
 in a close vessel. Friable aphrite ( Schaumkalk, Schaumerde) was formerly supposed 
 to be a variety of calcspar, but has been shown by Gustav Rose to be arragonite, 
 pseudo-morphosed in the form of gypsum. It occurs sometimes in the form of 
 gypsum-crystals, sometimes as a crystalline or laminar, white or yellowish-white mass. 
 The crystals exhibit a strong nacreous lustre on the cleavage-faces. Its specific 
 gravity, after thorough boiling with water to free it from air, is 2*98. Aim or albene 
 is a mineral resembling mountain-milk, extensive formations of which are found in 
 Southern Bavaria, where indeed it forms a subsoil many feet in thickness. Osteocolla 
 (Beinbruchstein) is a carbonate of calcium mixed with sand and organic remains, 
 which collects round decaying roots, and takes their peculiar forms ; it is found in the 
 neighbourhood of Berlin. Its specific gravity is 2'82. It exhibits, under the micro- 
 scope, the form of arragonite mixed with granular masses. 
 
 Arragonite consists of carbonate of calcium, C0 3 Ca 2 , or CaO.CCP, sometimes pure, 
 sometimes mixed with small quantities of the isomorphous compound, carbonate 
 of strontium, which, in the arragonite of Molina, amounts to 4 per cent. ; small quan- 
 tities of the carbonates of magnesium, manganese, iron, &c., are also occasionally 
 found in it. A peculiar variety called tarnowitzite, from Tarnowitz in Upper Silesia, 
 contains 3-86 per cent, of carbonate of lead. The chemical properties of arragonite are 
 essentially the same as those of carbonate of calcium in its other forms ; dilute acids, 
 however, act upon it less quickly than on calcspar, so that when a mixture of calcspar 
 and arragonite is immersed in a very dilute acid, a residue of arragonite is obtained 
 after a while. 
 
 Carbonate of calcium, in its two forms of calcspar (rhombohedral), and arragonite 
 (rhombic or right prismatic), exhibits one of the most striking examples of dimor- 
 phism, thai is to say, of the same chemical compound crystallising in two forms be- 
 
ARROW-ROOT ARSENIC. 359 
 
 longing to different systems (see DIMORPHISM). Formerly, when the existence of 
 dimorphism was unknown, the deviation of arragonite from the more ordinary form of 
 carbonate of calcium was attributed to the presence of carbonate of strontium, which 
 always crystallises in the rhombic system. It was found, however that this mineral 
 was present in arragonite, often in extremely minute quantities, or indeed absent 
 altogether, the form still remaining the same ; and thus the fact of the dimorphism 
 of carbonate of calcium became apparent. 
 
 Arragonite and calcspar exhibit many differences in their physical properties. 
 Arragonite has two axes of double refraction ; calcspar only one. Arragonite has less 
 specific heat (0 % 1966) than calcspar, greater hardness and greater density. Large 
 crystals of arragonite frequently decrepitate when heated, then swell up suddenly and 
 fall to powder ; smaller pieces, or fibrous arragonite, become turbid and rotten. The 
 mineral after this change is found to have the density of calcspar ; indeed the change 
 appears to consist in the passage of the arragonite to the form of calspar. This action 
 may explain the pseudomorphoses of calcspar in the form of arragonite. Mitscherlich 
 describes a crystal of arragonite from Vesuvius, which had been converted into calc- 
 spar on the outside by the action of the red-hot lava, while its interior still retained 
 the structure of arragonite. 
 
 The circumstances which have determined the crystallisation of carbonate of cal- 
 cium in one form or the other are not precisely known; it appears, however, to 
 assume by preference the form of arragonite, when it crystallises from hot solutions. 
 According to H. Rose (Pogg. Ann. xlii. 363), the precipitate formed on mixing the 
 boiling solutions of chloride of calcium and carbonate of ammonium, consists of micro- 
 scopic crystals of arragonite, which, however, change into rhombohedrons of calcspar 
 if left for some time under the cold liquid. 
 
 The occurrence of arragonite in the deposits of hot calcareous springs points to the 
 same conclusion. The concentration of the liquid appears also to exert some influence. 
 According to Becquerel (Compt. rend, xxxiv. 29 and 573), when gypsum is im- 
 mersed at ordinary temperatures in a concentrated solution of acid carbonate of so- 
 dium, carbonate of calcium is deposited in the form of arragonite, but if the solution 
 of the acid carbonate of sodium is dilute, the deposit takes the form of calcspar. On 
 the whole it would appear that the tendency to the assumption of the arragonite form 
 increases with the rapidity of the crystallisation. 
 
 ARROW-ROOT. The starch of the Maranta arundinacea, a plant belonging 
 to the order Marantacece, and cultivated both in the East and West Indies. Ac- 
 cording to Benzon, the root has the following composition: Starch 26-00 per cent.; 
 woody fibre 6'00 ; albumin T53; chloride of calcium - 25; water 65'60 per cent. 
 In the island of St. Vincent, the skinned tubers are washed and ground in a mill, 
 and the pulp is washed in cylinders of tinned copper with perforated bottoms. To 
 obtain the fecula free from impurity, great care must be used in every step of the 
 process. Palette knives of german silver are used for skinning the deposited fecula, 
 and even shovels of the same material for packing it. The drying is effected in pans, 
 covered by white gauze to exclude dust and insects. 
 
 The term arrow-root is applied generically to indicate a starch or fecula ; thus Port- 
 land arrow-root is obtained from Arum maculatum; East India arrow-root, from 
 Curcuma angustifolia; Brazilian, from latropha manihot ; Tahiti arrow-root, from 
 Tacca oceanica ; English, from the potato. 
 
 Arrow-root, like the rest of the starches, contains C' 2 H 20 10 . The cheaper feculas 
 are sometimes substituted for genuine arrow-root ; but they are readily detected by 
 the microscope. Arrow-root is one of the most palateable and digestible of the 
 starches. The expressed juice of the plant has been used as an antidote to poisons and 
 to the bites and stings of venomous insects. (See Ure's Dictionary of Arts, Manufac- 
 s, and Mines, i. 182.) . 
 
 ARSA. An alcoholic liquor, procured by the Tartars from fermented mare's milk 
 (Kumis). In the weak state it is called araca; after rectification, arsa. 
 
 ARSENIC. (Arscn, Scherbenfiobalt, Fliegengift, NapchenJcobalt, Arsenicum, Re- 
 gulus Arscnici, the apa-wiKbv of Dioscorides.) Symbol, As. Atomic weight, 75. 
 Vapour-density, 150 (hydrogen = l) ; Atomic volume, . 
 
 History. This element has been known from very early times, chiefly as sulphide 
 and arsenious acid. The first accurate investigation of its chemical nature was made 
 by Brandt in 1733. Scheele, in 1755, discovered arsenic acid and arsenetted hydro- 
 gen gas. Sir H. Davy discovered the solid arsenide of hydrogen. The stoichio- 
 metrical relations of arsenic and its numerous sulphur-compounds, were specially 
 investigated by Berzelius. Bunsen in 1842 discovered cacodyl, an organic radicle 
 containing arsenic and methyl, and several other organic arsenic-radicles have since 
 been discovered by Landolt and others. 
 
 A A 4 ' 
 
360 ARSENIC. 
 
 Occurrence. Arsenic is found native, but much more frequently associated with 
 other metals and with sulphur. The ores from which it is prepared on the large scale, 
 as a principal product, in the form of metallic arsenic or arsenious oxide, are : native 
 arsenic, As ; arsenical iron, two species, FeAs, and Fe 4 .As 3 ; and arsenical pyrites, 
 FeAs + FeS 2 . Metallic arsenic and arsenious oxide are likewise obtained as secondary- 
 products from smaltine, cloanthite, arsenical cobalt, cobalt-glance, nickel-glance, copper- 
 nickel, arsenical nickel, arsenical fahl-orcs, and other ores of similar character. 
 
 These arsenical ores are found more or less abundantly in various parts of the 
 world, but chiefly in the mining districts of Germany and in the Spanish province of 
 Catalonia. In small quantities, arsenic is very widely diffused, being found in the 
 ferruginous deposits of mineral waters (Will, Ann. Ch. Pharm. Ixi. 192) ; in nearly all 
 iron ores (Walchner, ibid. 209) ; in the various kinds of pyrites, and in native sulphur. 
 Hence also it is almost always found in sulphuric acid, and in numerous chemical and 
 pharmaceutical products, in the preparation of which sulphuric acid is used. In short, 
 arsenic in small quantities is one of the most widely diffused substances in nature. 
 It was said by Orfila (J. Chim. med. xv. 462, 632) to exist also in the bones and 
 muscles of men and animals in a state of health ; but the experiments of other chemists 
 have shown this statement to be erroneous. 
 
 Preparation. Metallic arsenic is obtained on the large scale by heating native 
 arsenide of iron, FeAs or Fe 4 As 3 , or arsenical pyrites, Fe 2 AsS, in earthen tubes or 
 retorts : the whole of the arsenic then sublimes, and iron or protosulphide of iron 
 (Fe 2 S) remains behind. The retorts are laid horizontally in a long furnace, a tube 
 made by rolling up a piece of thin iron plate, is inserted into their mouths, and an 
 earthen receiver luted on. The arsenic condenses chiefly in the iron tube, in the form 
 of a coherent internally crystalline mass, and when the tube has cooled, is detached by 
 unrolling it. The arsenic thus obtained is purified, if necessary, by a second sublima- 
 tion. The metal is also prepared by heating arsenious oxide with charcoal in earthen 
 crucibles, surmounted by inverted crucibles, or by conical iron caps. This is the 
 process adopted at Altenberg, in Silesia, It is more productive and economical than 
 the former, but the metal which it yields is grey and pulverulent, whereas the former 
 is compact and nearly white. Arsenic may also be obtained from its sulphides, by 
 heating those compounds with a mixture of charcoal and an alkaline carbonate or 
 cyanide of potassium. (Kerle's Hiittenkunde, iii. 4.) 
 
 Properties. Arsenic is a very brittle metal, of a steel-grey colour. Its specific 
 gravity in the solid state is, according to different observers, between 5'62 and 5*96. 
 Vapour-density = IG'3995 (air = 1), or 150 (hydrogen = 1), which -is double the 
 atomic weight; hence the atomic volume of arsenic vapour is anomalous, being only 
 half that of hydi'ogen. (See ATOMIC VOLUME.) Arsenic crystallises in rhombohedrons, 
 isomorphous with tellurium and antimony. It volatilises at a dull red heat, without 
 previous fusion, emitting a characteristic disagreable odour resembling that of garlic. 
 Its physical properties vary considerably with the manner in which it is sublimed. 
 "When very strongly heated, or when it condenses on a part of the subliming apparatus, 
 the temperature of which is but little below that at which arsenic volatilises, so 
 that the metal is deposited in an atmosphere of its own vapour, it condenses in a 
 compact, nearly white mass, having a strong metallic lustre. This compact arsenic 
 scarcely oxidises in the air, even when pulverised and exposed to a temperature 
 of 80 C. Such is the condition of the~metal obtained by heating arsenical pyrites. 
 When, on the contrary, the arsenic, as it passes into the gaseous form, becomes 
 mixed with other gases (as when it is reduced from arsenious acid by charcoal), or 
 when it is deposited on the colder parts of the subliming apparatus, it solidifies in a 
 dark grey crystalline powder, less dense than the preceding, and oxidising readily in 
 the air, especially when heated. 
 
 Native arsenic forms botryoi'dal, kidney-shaped, spherical, and conchoidal masses, 
 varying in texture from fine-grained to compact ; less frequently, indistinct rhombo- 
 hedral crystals. In the recent state, it has a light lead-grey colour, but soon becomes 
 greyish-black by exposure to the air. In its chemical properties, it resembles artifi- 
 cially prepared arsenic. It is found in various localities of the Saxon and Bohemian 
 mining districts, at Andreasberg in the Harz, at Kapnik in Transylvania, Kongsberg 
 in Norway, and several places in the United States of America. 
 
 Arsenic forms two principal series of compounds, analogous to those of antimony and 
 phosphorus, viz. the arsenious compounds in which it is triatomic, e.g. AsH 3 , 
 AsCl 3 , (As) 2 3 , (As) 2 S 3 , &c., and the arsenic compounds in which it is pentatomie, 
 
 e. g. ( As) 2 O 5 , (As) 2 S 5 , &c. Besides these, there are a few compounds into which it 
 enters in other proportions, c. y. the sulphide AsS, and several alloys. 
 
ARSENIC: DETECTION. 361 
 
 Many compounds of arsenic are isomorphous with the corresponding compounds of 
 phosphorus and antimony, e. g. rhombic arsenious oxide is isomorphous with native tri- 
 oxide of antimony : the salts of arsenic acid are isomorphous with the corresponding 
 phosphates. 
 
 DETECTION AND ESTIMATION OF AESENIC. 
 
 I. Reactions in the dry way. Metallic arsenic, heated with but slight access 
 of air, as in a narrow test-tube, is converted into a vapour having the peculiar al- 
 liaceous odour already mentioned, and condenses on the cold part of the tube in a 
 shining, brownish-black, metallic, ring. With greater access of air, as when a small 
 quantity of the metal is heated in a wide test-tube, or in a tube open at both ends and 
 held over a lamp in a slanting position, the arsenic is converted into arsenious oxide, 
 which condenses on the cold part of the tube in a white crystalline ring, soluble in 
 boiling water. 
 
 The oxides of arsenic heated with charcoal or other deoxidising substances, are 
 reduced to the metallic state, the metallic arsenic thus liberated exhibiting the cha- 
 racters just mentioned. If a small quantity of arsenious oxide be placed on charcoal, 
 and the point of the blowpipe flame directed upon it, a greyish-white smoke is imme- 
 diately evolved, accompanied by a powerful alliaceous odour; and if the arsenious 
 oxide be mixed with perfectly dry and coarsely pounded charcoal, and heated to red- 
 ness at the bottom of a small test-tube, a ring of metallic arsenic will be deposited on 
 the cold part of the tube. 
 
 The sulphides of arsenic, and the salts of arsenious and arsenic acid, are not easily 
 reduced by ignition with charcoal alone, but when heated with carbonate of potassium 
 or sodium, or with a mixture of an alkaline carbonate and charcoal, or cyanide of potas- 
 sium, they yield metallic arsenic with its characteristic properties. 
 
 II. Reactions in the wet way. a. Of Arsenious Compounds. Hydrosulphiiric 
 acid gas passed into an aqueous solution of arsenious acid, colours it yellow, and on 
 addition of hydrochloric acid, throws down the whole of the arsenic in the form of 
 bright yellow trisulphide. The precipitate is said to be perceptible in a solution con- 
 taining not more than 1 pt. of arsenious acid in 160,000 pts. of water. The precipitate 
 dissolves easily in ammonia, carbonate of ammonium, and sulphide of a-mmonium, and 
 is reprecipitated without alteration by hydrochloric acid. It is likewise soluble in 
 a considerable quantity of boiling water, and in boiling dilute hydrochloric acid, with 
 liberation of hydrosulphuric acid gas. (Odling, Guy's Hospital Reports [3] i. 239.) 
 
 Nitrate of silver added to aqueous arsenious acid produces a scarcely appreciable yellow 
 turbidity, and on cautiously adding ammonia, a canary-yellow precipitate of arsenite of 
 silver, which dissolves with great facility in nitric acid, acetic acid, and excess of ammonia. 
 Hence, if the quantity of arsenic present is but small, it is difficult to avoid adding too 
 much ammonia, and thus preventing altogether the formation of the precipitate. This 
 inconvenience may however be obviated by using a solution of nitrate of argcntam- 
 monium, commonly called ammonia-nitrate of silver, prepared by treating a solution 
 of nitrate of silver with a quantity of ammonia sufficient to redissolve only a portion 
 of .the precipitated oxide of silver, and filtering. Such a solution contains exactly the 
 proportion of ammonia required to precipitate the arsenious acid as arsenite of silver. 
 If, however, an excess of nitric acid is present, a further quantity of ammonia will be 
 required to neutralise it. In a neutral solution of an arsenite of alkali-metal, nitrate 
 of silver produces an immediate precipitate of arsenite of silver. 
 
 With sulphate of copper, on addition of ammonia, arsenious acid forms a bright green 
 precipitate of arsenite of copper (Scheele's green), easily soluble in acids and in am- 
 monia. In this case also, it is convenient to use a solution of sulphate of cupram- 
 monium, or ammonio-suJphate of copper, S0 4 (NH 3 Cu) 2 , prepared in the same manner 
 as the ammonio-nitrate of silver. 
 
 Nitric acid, hypochlorous acid, chromic acid, and other oxidising agents, convert 
 arsenious acid into arsenic acid. With a solution of trichloride of gold, it yields arsenic 
 acid, and a black precipitate of metallic gold. 
 
 A piece of metallic copper immersed in a hot solution of arsenious acid or an arsenite, 
 mixed with hydrochloric acid, becomes covered with a grey film of metallic arsenic, 
 which may be sublimed and converted into arsenious oxide by heating the coated 
 metal in a dry glass tube (Reinsch's test). 
 
 Zinc immersed in a solution of arsenious acid or an arsenite acidulated with hydro- 
 chloric or sulphuric acid, likewise reduces the arsenic to the metallic state, part of the 
 reduced arsenic being deposited as a black film on the zinc, while the rest unites with 
 the nascent hydrogen and escapes as gas ; and from this gas, which burns with a 
 peculiar greyish flame, the arsenic may be separated in the metallic state, either by 
 passing the gas, after drying with chloride of calcium, through a narrow glass tube, 
 one part of which is heated to redness over a lamp, the metal being then deposited 
 
362 ARSENIC: DETECTION. 
 
 in the cold part of the tube beyond the flame ; or else by burning the gas at the 
 extremity of the tube drawn out to a fine jet, and holding in the flame, near the 
 orifice, a plate of clean white porcelain. The arsenic is then deposited on the plate in 
 brownish-black, shining metallic films, which may be distinguished from those of 
 antimony formed in like manner (pp. 320, 322), by their solubility in aqueous hypo- 
 chlorite of sodium, and by other characters to be noticed hereafter. 
 
 This reaction, which is known as Marsh's test, is extremely delicate, and is therefore 
 much used in searching for minute quantities of arsenic, especially in cases of poisoning. 
 A convenient apparatus for the purpose is that represented in fig. 72. A is the gene- 
 rating vessel, provided with a funnel-tube B, for introducing the acid and the solution 
 
 Fig. 72. 
 
 to be tested, c is a drying-tube containing chloride of calcium ; D E the reduction-tube 
 which should be of hard glass, free from lead. It is convenient to have this tube 
 contracted at one or two points, as shown in the figure, and turned up at right angles 
 at the end, so as to form a vertical jet. The first thing to be done is to ascertain 
 whether the zinc and acid are free from arsenic. For this purpose, they must be intro- 
 duced into the generating vessel, without the solution under examination, and after the 
 evolution of gas has continued long enough to expel atmospheric air, the reduction- 
 tube is to be heated at a by a lamp-flame for about a quarter of an hour, and the gas 
 set on fire at the jet F, a piece of white porcelain being held in the flame. If no de- 
 position of arsenic takes place either in the tube or on the porcelain, the liquid to be 
 tested is then to be poured in through the funnel-tube and the heating continued. If 
 arsenic is present, it will be deposited in a shining mirror at b, a little beyond the 
 flame. After a sufficient deposit has been obtained at that point, the lamp may be 
 removed to c, when a second deposition will take place at d, and so on. If the quan- 
 tity of arsenic is considerable, spots may also be opined on a plate of porcelain held 
 in the flame at E. The portions of the reduction-tube containing the deposits may 
 then be cut off with a file, sealed, and reserved for further examination. Instead of 
 burning the escaping gas -at E, it may be passed, by means of a tube joined to the 
 reduction-tube by a caoutchouc connector, into a solution of nitrate of silver. Metallic 
 silver will then be deposited, and the whole of the arsenic will remain in solution as 
 arsenious acid. 
 
 A solution of arsenious acid acidulated with hydrochloric or sulphuric acid, is de- 
 composed by the electric current, the greater part of the arsenic eliminated at the 
 negative pole being given off in the form of arsenetted hydrogen, which may be 
 examined as above (Bio x am, Chem. Soc. Qu. J. xiii. 14). The apparatus used 
 consists of a two-ounce narrow-mouthed bottle, the bottom of which has been cut off 
 and replaced by a piece of vegetable parchment tightly stretched over it, and secured 
 by a ligature of platinum wire (any ligature of organic nature, even vulcanised caout- 
 chouc, would be quickly destroyed by the ozone evolved at the positive pole). The 
 bottle is furnished with a cork, carrying a small tube bent at right angles, and at- 
 tached to the reduction-tube by a caoutchouc joint, also a funnel-tube for introducing 
 the liquid to be tested. Through the cork there likewise passes a platinum wire, 
 carrying a plate of _the same metal, which forms the negative pole of the voltaic cir- 
 cuit. The bottle is placed within a glass of such a size as to leave a small interval 
 between the two, this glass standing in a vessel of cold water. An ounce of dilute 
 sulphuric acid is introduced into the apparatus, so as to fill the bottle and the outer 
 
ARSENIC: DETECTION. 363 
 
 space to about the same level, the positive plate being immersed in the acid contained 
 in this outer space. The current of a voltaic battery (6 Grove's cells of ordinary size) 
 is then passed through the arrangement, and the shoulder of the reduction-tube is 
 heated to redness for about a quarter of an hour, to ascertain whether any deposit of 
 arsenic is produced from the sulphuric acid itself : if the result be negative, the liquid 
 to be tested is then introduced through the funnel-tube and the heating of the reduc- 
 tion-tube is continued. This method is extremely delicate, even j~ of a grain of 
 arsenious acid diffused through a considerable quantity of liquid, producing a per- 
 ceptible deposit in the reduction-tube after 15 30 minutes. 
 
 The electrolytic method of eliminating arsenic possesses certain advantages over that 
 of Marsh : 1. It avoids the use of zinc, and thereby obviates a frequent source of error 
 arising from the presence of arsenic in that metal. 2. It introduces no substance into 
 the liquid that can interfere with its subsequent examination for other metals. 3. If 
 any other metals are present, it precipitates them on the surface of the negative plate. 
 Even antimony is for the most part precipitated in this manner. When the reduction 
 is effected by zinc, antimony if present is evolved, together with the arsenic (p. 322), 
 and the subsequent separation of these metals is troublesome ; but with the electrolytic 
 method, as above described, only a very small quantity of antimony is evolved as anti- 
 monetted hydrogen ; and even this quantity may be completely arrested by adding to 
 the liquid a solution of hydrosulphuric acid. Both antimony and arsenic are then 
 converted into sulphides ; but the sulphide of arsenic is reduced by the electrolytic 
 hydrogen as easily as arsenious acid (see below), whereas the sulphide of antimony 
 completely resists the action of that agent, and remains in the liquid. 
 
 )8. Of Arsenic Compounds. A solution of arsenic acid gives with nitrate of silver, 
 without addition of ammonia, a red-brown precipitate of arsenate of silver easily soluble 
 in ammonia and in nitric acid. It does not precipitate sulphate of copper until am- 
 monia is added, and the precipitate then produced is of a pale bluish-white colour, 
 quite distinct from Scheele's green. With sulphate of magnesium, ammonia, and 
 chloride of ammonium (the last being added to prevent the precipitation of hy- 
 drate of magnesium), arsenic acid forms a white crystalline precipitate of arsenate 
 of magnesium and ammonium, AsMg 2 (NH 4 )0 4 + 6H 2 0, similar in appearance and 
 in constitution to the phosphate of magnesium and ammonium. If the solution 
 is very dilute, the precipitate does not appear immediately but is deposited in 
 crystals, after a few hours on the sides of the tube. Molybdate of ammonium added in 
 excess to a solution of an arsenate containing free nitric acid, yields, when the liquid 
 is heated, a bright yellow precipitate of arseno-molybdate of ammonium ; exactly 
 similar to the phosphomolybdate (see PHOSPHORIC ACID). This precipitate is in- 
 soluble in acids, but soluble in ammonia, and in excess of the arsenic solution ; hence 
 it is especially adapted for detecting small quantities of arsenic acid, and is indeed 
 one of the most delicate tests for that acid, provided no phosphoric acid is pre- 
 sent. With sesquisalts of iron and uranium, arsenic acid forms yellowish- white 
 precipitates. With lead-sa'ts, it forms a white precipitate of arsenate of lead, which 
 when heated on charcoal in the inner blowpipe flame, gives off the odour of arsenic, 
 and yields a button of metallic lead. Hydrosulphuric acid gas passed through a solution 
 of arsenic acid colours it yellow at first, and after a long time produces a yellow pre- 
 cipitate of trisulphide of arsenic, mixed with sulphur, the precipitation being accelerated 
 by heat. A solution of a neutral arsenate of alkali-metal, through which hydro- 
 sulphuric acid gas is passed, yields the same precipitate on addition of hydrochloric 
 acid. Sulphurous acid, phosphorous acid, and other deoxidising agents reduce arsenic 
 acid in solution to the state of arsenioxis acid. Hence in a solution of arsenic acid 
 mixed with sulphurous acid or a soluble acid sulphite, hydrosulphuric acid produces 
 an immediate precipitate of trisulphide of arsenic. 
 
 Nascent hydrogen evolved by the action of zinc on dilute sulphuric or hydrochloric 
 acid, converts arsenic acid into arsenetted hydrogen, which is evolved as gas (Scheele, 
 L. Gmelin); but the action is much slower than with arsenious acid. When an 
 electric current is passed through a solution of arsenic acid, metallic arsenic is 
 deposited on the negative pole (Gmelin's Handbook, iv.), and arsenetted hydrogen is 
 evolved provided no chlorides are present (Bloxam) ; on adding sulphurous acid, or 
 acid sulphite of sodium to the solution, whereby the arsenic acid is reduced to arsenious 
 acid, the evolution of arsenetted hydrogen is greatly accelerated. The same effect is 
 produced, even with greater certainty on adding aqueous hydrosulphuric acid to the 
 solution. This effect is also chiefly due to the reduction of the arsenic acid to 
 arsenious acid ; but even when the hydrosulphuric acid is added in excess, the evolu- 
 tion of the arsenetted hydrogen still takes place, the arsenic uniting with the hydrogen 
 in preference to the sulphur. (Bloxam, Chem. Soc. Qu. J. xiii. 138.) 
 
 Compounds insoluble in water, may be examined for arsenic by dissolving them in 
 
364 ARSENIC: DETECTION. 
 
 hydrochloric acid ; passing hydrosulphuric acid gas through the solution ; digesting 
 the precipitate with sulphide of ammonium, to dissolve out the sulphide of arsenic ; 
 and precipitating the sulphide of arsenic by hydrochloric acid. The precipitate may 
 then be dried, and reduced by heating with carbonate of sodium and charcoal, or dis- 
 solved in hydrochloric acid, with addition of chlorate of potassium, and the solution, 
 which will contain arsenic acid, tested as above. 
 
 The following characters taken together are sufficient to distinguish arsenic from all 
 other substances. 
 
 1. Formation of a black shining metallic sublimate by one of the methods of reduc- 
 tion above described. 
 
 2. Conversion of this metallic deposit into white crystalline arsenious oxide by sub- 
 limation in contact with the air. 
 
 3. Solution of this sublimate in boiling water, and production of the reactions charac- 
 teristic of arsenious acid, viz. yellow with hydrosulphuric acid, yellow with ammonio- 
 nitrate of silver, light green with ammonio-sulphate of copper. 
 
 4. Solution of the metallic sublimate in hot nitric acid, and production of the re- 
 actions characteristic of arsenic acid, viz. red-brown with nitrate of silver, white 
 crystalline with ammonia and magnesium-salts, bright yellow with molybdate of 
 ammonium. 
 
 The metal with which arsenic is most likely to be confounded, is antimony, 
 especially when the reduction to the metallic state is effected by Marsh's method, 
 (pp. 320, 322.) The arsenical and antimonial deposits obtained in this manner, may 
 however be distinguished by the following characters : 
 
 The arsenic-mirror has a strong lustre, and a black-brown, or brown-black colour ; 
 thin films of it formed in a glass tube, appear perfectly translucent, with brown colour, 
 when held before white paper. On account of the volatility of arsenic, the deposit 
 is formed only at a certain distance from the heated portion of the tube, and always 
 on the side towards which the stream of gas is directed. The spots formed on porce- 
 lain have a black-brown, or when very thin, a brown or light brown colour. The 
 antimony mirror on the contrary is formed in the reduction tube on both sides of the 
 flame and close to it. Where most strongly heated, it has a whiter colour, and when 
 examined by a lens, exhibits small fused metallic globules. It is brownish in thin 
 films, but not continuously brown and shining, like that of arsenic. Antimony-spots 
 formed on porcelain are velvet black, and without lustre, unless very thin ; in that case 
 they have an iron-black, or dark plumbago colour, brownish-grey at the edges. 
 
 If the part of the reduction-tube containing the arsenic-mirror be cut off, and heated 
 in a small lamp flame, the flame exhibits the characteristic greyish colour, and the 
 strong garlic odour of arsenic becomes perceptible. If the pieces of tube covered 
 with arsenic are heated in a narrow test-tube, the characteristic white crystalline 
 sublimate of arsenious oxide is formed, perfectly soluble in boiling water, and ex- 
 hibiting the characters above-mentioned. 
 
 The antimony- deposit does not give off any odour when heated in a lamp-flame, and 
 if heated in a wide test-tube, yields a white shining sublimate of oxide, which is in- 
 soluble in water and in ammonia, but dissolves readily in hydrochloric acid, the solu- 
 tion yielding with hydrochloric acid the characteristic red precipitate of antimonious 
 su'phide. 
 
 The arsenic-mirror dissolves readily in an alkaline solution hypochlorite of sodium, 
 the solution exhibiting the characters of arsenic acid. The antimony-mirror is in- 
 soluble in the same liquid, provided it does not contain free chlorine. 
 
 Nitric acid of specific gravity 1'2 to T3 dissolves the arsenic deposit in the cold, or 
 at a gentle heat, the solution exhibiting the characters of arsenious acid ; at a stronger 
 heat, arsenic acid is formed. The same acid likewise dissolves the antimony mirror, 
 but the solution is turbid, gives no precipitate with nitrate of silver and ammonia, 
 orange-yellow, with hydrosulphuric acid. 
 
 A very good way to identify arsenic spots is to collect one or more in a watch-glass, 
 add a drop or two of nitro-hydrochloric acid evaporate quite to dryness, moisten 
 with water, and then add nitrate of silver solution. 
 
 Yellow sulphide of ammonium dissolves arsenic spots with great difficulty, and 
 never completely ; and on evaporating to dryness, there is always left a grey stain of 
 arsenic in the midst of the yellow orpiment. Antimony spots dissolve at once and 
 completely, and the orange-red sulphide of antimony left on evaporation, dissolves 
 completely in hydrochloric acid, being converted into chloride, which volatilises, or 
 leaves only a slight residue of white antimonious oxide. 
 
 The arsenic-deposit is easily dissolved in the cold by hydrochloric acid with addition 
 of chlorate of potassium, and the solution yields, with magnesium-salts, mixed with 
 ammonia and tartaric acid, the crystalline precipitate characteristic of arsenic acid. 
 
ARSENIC: DETECTION. 365 
 
 The antimony-deposit similarly treated, dissolves only when heated, and the solution 
 mixed with tartaric acid and ammonia is not precipitated by magnesium-salts. 
 
 When arsenetted hydrogen is passed into a solution of nitrate of silver, metallic 
 silver is precipitated, and all the arsenic remains in solution as arsenious acid, which 
 may be precipitated by sulphuretted hydrogen, &c.; but when antimonetted hydrogen 
 is passed into nitrate of silver, the whole of the antimony is precipitated in the 
 metallic state, together with the silver, and the solution, after being freed from excess 
 of silver by hydrochloric acid, gives no precipitate with sulphuretted hydrogen. 
 
 It often happens that antimony and arsenic are evolved together as gaseous hy- 
 drogen-compounds. In that case, the two metals may be separated by the reaction 
 with nitrate of silver just mentioned * ; by dissolving the metallic mirror in hydro- 
 chloric acid, with addition of chlorate of potassium, then adding tartaric acid and 
 ammonia, and precipitating the arsenic by sulphate of magnesium ; or by gently heat- 
 ing the deposit in a very slow stream of dry sulphuretted hydrogen, whereby both are 
 converted into sulphides, and then passing dry hydrochloric acid through the tube. 
 The sulphide of antimony is thereby converted into chloride, which passes on with the 
 stream of gas, and may be received in water and further tested, while the sulphide of 
 arsenic remains unaltered. If the hydrochloric acid gas is not perfectly dry, a small 
 portion of the antimony will be left behind as oxide. 
 
 For other methods of separating arsenic and antimony, see page 368. 
 
 Detection of Arsenic in cases of Poisoning. Nearly all compounds of 
 arsenic are poisonous, the most soluble being, generally speaking, those which act with 
 the greatest violence. But arsenious oxide, commonly called arsenious acid, being the 
 most generally known and easily procured, is that which is most likely to be met with 
 in cases of poisoning by arsenic, whether accidental or intentional. 
 
 As arsenious oxide is but sparingly soluble in water, and is generally administered 
 in the solid state, mixed with viscid articles of food, such as gruel or rice, it some- 
 times happens that, by careful examination, small lumps of it may be found adhering 
 to culinary vessels, &c., or even to the coatings of the stomach and intestines after 
 death. When this is the case, the arsenic may be picked out and reduced to the 
 metallic state by heating it with charcoal. 
 
 If the arsenious oxide is too finely divided to be picked out in this manner, it may 
 sometimes be separated by stirring up the mass several times with water, and leaving 
 the heavier particles to settle. Any solid arsenious acid that may be present will be 
 sure to be found in the residue, and may then be washed with cold water and dried 
 over the water-bath. 
 
 The oxide thus separated may be reduced to the metallic state by heating it in 
 a small test-tube with charcoal, as described as page 361. A good way of effect- 
 ing the reduction, is to place the dried granules or powder at the bottom of a small 
 test-tube, drawn out as shown in fig. 73, and place above it a splinter of well-dried 
 
 Fig. 73. 
 
 1 
 
 charcoal, a. The tube is first held in a horizontal position with the part a in the 
 flame of a lamp, so as to heat the charcoal to redness ; it is then gradually inclined 
 to volatilise the arsenious acid, and cause the vapour to pass over the ignited charcoal. 
 A speculum of metallic arsenic then collects at the shoulder of the tube, and may after- 
 wards be reconverted into arsenious oxide by sublimation in contact with the air, as 
 already described (p. 361). 
 
 More frequently, however, the arsenic is intimately mixed with large quantities of 
 organic matter, such as articles of food, vomited or evacuated matters, portions of the 
 animal body, as the stomach, liver, &c. In such cases, Keinsch's test (p. 361)maybe 
 very conveniently applied. The suspected matter, if liquid, is acidulated with about 
 one -sixth of its bulk of hydrochloric acid and boiled. The solid tissue is cut up into 
 very small pieces and boiled for some time in a mixture of 1 pt. of hydrochloric acid, 
 and 6 parts of water, till the whole is completely disintegrated, and then strained 
 through muslin, or filtered through paper previously wetted. Pieces of copper-gauze or 
 foil are then to be immersed in the boiling liquid, and if any grey deposit is produced, 
 fresh pieces must be added as long as any perceptible alteration of colour takes place 
 on the surface of the metal. They are then to be removed, washed with distilled 
 
 * The best mode of detecting small quantities of antimony thus precipitated is, after carefully washing 
 out the arsenious acid, to digest the precipitate in aqueous tartaric arid ; the antimony then alone dis- 
 golves, and may be tested by hydrosnlphuric acid. (Hofmaun, Chem. Soc. Qu. J. xiii. 79.) 
 
366 ARSENIC: DETECTION. 
 
 water, and dried between bibulous paper, folded up, introduced into a dry test tubty 
 and heated over a lamp. The arsenic is thereby converted into arsenious oxide, which 
 collects on the cold part of the tube in the form of a crystalline sublimate. It may be 
 dissolved in water and tested with nitrate of silver, &c. Inasmuch as Reinsch's pro- 
 cess involves the solution of a minute quantity of copper, the foil or gauze employed 
 should be so far free from arsenic that the solution of four or five grains of it should 
 not yield a trace of the poison. 
 
 The arsenic may also be detected by other methods which, however, for the most 
 part require more complete destruction of the organic matter. This may be effected 
 by one of the following processes : 
 
 1. The organic matter is mixed with about a fourth of its weight of strong sul- 
 phuric acid, and heated till the whole is reduced to a dry friable carbonaceous mass ; 
 and this residue, after being pulverised, is treated with nitric acid mixed with a small 
 quantity of hydrochloric acid, in order to bring the arsenic to the state of arsenic acid, 
 which is very soluble in water. The mixture is then evaporated to dryness, and the 
 residue boiled with water and filtered. If the organic matter contains alkaline chlorides, 
 which is frequently the case, care must be taken not to heat it more strongly than is 
 necessary for complete incineration, otherwise a portion of the arsenic maybe converted 
 into chloride and lost by volatilisation. 2. The organic matter is gently heated in a 
 tubulated retort with strong hydrochloric acid, and nitric acid is added by small 
 portions at a time. The organic matter is thereby completely destroyed, with the 
 exception of the fat. The liquid, which is transparent and colourless, is then decanted 
 from the fatty matters ; the latter are well washed with water ; and the washings, toge- 
 ther with the distillate in the receiver, are added to the main bulk of the liquid (G au 1 - 
 tier de Claubry, J. Pharm. [3] xvii. 125). 3. Chlorate of potassium may also be 
 added in successive portions instead of the nitric acid. 4. The organic matter, after 
 being comminuted as much as possible, may be suspended in water, and chlorine gas 
 passed through the liquid till the organic matter is partly destroyed and partly de- 
 posited in brown flakes. 5. The organic matter, after being dried, is mixed with 
 nitre, and the mixture projected by successive portions into a red-hot crucible. The 
 arsenic is thereby converted into arsenate of potassium, which dissolves readily in 
 water. (Wohler.) 
 
 Mr. Graham finds that a most effective separation of the organic matter capable of 
 interfering with the precipitation of arsenic by reagents, may be effected by his appa- 
 ratus for the diffusion of liquids. A flat hoop of white wood or gutta-percha, about 
 ten inches in diameter, is covered with a sound sheet of parchment-paper, so as to form 
 an instrument like a tambourine in form. The organic fluid is placed within the 
 instrument so as to cover the parchment bottom to the depth of half an inch, and the 
 whole is then floated upon distilled water, contained in a basin. Three-fourths of the 
 arsenious acid present are found to escape by diffusion and enter the water below, in 
 the course of twenty-four hours, giving a perfectly colourless solution. To this liquid, 
 when concentrated, all the ordinary tests of arsenic may be applied. (See DIFFUSION 
 OF LIQUIDS.) 
 
 A clear solution having been obtained, the arsenic may be separated from it in 
 either of the following ways : 
 
 1. By Precipitation as TrisulpMde. The clear arsenical solution is saturated with sul- 
 phurous acid to reduce the arsenic acid to arsenious acid, the excess of sulphurous acid, 
 is expelled by gentle heating, and a stream of sulphuretted hydrogen gas passed through 
 the liquid for a considerable time. The precipitated trisulphide of arsenic is then care- 
 fully washed with cold water, dried, and reduced to the metallic state by heating it in a 
 small tube harving a bulb blown at the end with a mixture of dry carbonate of sodium and 
 charcoal, or cyanide of potassium. The bulb, after the introduction of the mixture, 
 should 'first be gently heated over a lamp to expel moisture, the tube then wiped out 
 with filtering paper, and the bulb strongly heated in the blowpipe flame. A ring of 
 metallic arsenic is then deposited in the tube, and may be treated as already described. 
 
 2. By Conversion into Arsenetted Hydrogen. This may be effected either by Marsh's 
 or by Bloxam's process (p. 362). The former has long been used by toxicologists. 
 It is extremely delicate, and indeed has nearly superseded all other methods, except- 
 ing that of Keinsch. If the liquid to be tested has been effectually freed from 
 organic matter by either of the methods just given, so that there is no longer any 
 danger of frothing, it may be introduced, together with the zinc and sulphuric acid, 
 into an ordinary gas-generating vessel, provided with a drying tube and reduction- 
 tube (p. 362). Peculiar forms of apparatus have, however, been devised for perform- 
 ing the process without the trouble of completely removing the organic matter. Such 
 is the original apparatus of Marsh, a figure and description of which are given in 
 Graham's Elements of Chemistry, 2nd ed. vol ii. p. 215. Another form of appa- 
 ratus, contrived for the purpose by a committee of the Prussian government, and 
 
ARSENIC: ESTIMATION. 367 
 
 simplified by the late Dr. Tire, is described in Ure's Dictionary of Arts, Manufac- 
 tures, and Mines, new edition, i. 189. 
 
 It is found however, that the presence of organic matter sometimes completely pre- 
 vents the detection of minute quantities of arsenic by Marsh's process (Odling, 
 Guy's Hospital Keports, [3] v. 367 ; Pharm. J. Trans. [2] i. 374). Hence it is better in 
 all cases, before applying this test, to eliminate the organic matter by one of the pro- 
 cesses above described. It must be observed, however, that all these processes yield 
 the arsenic in the form of arsenic acid, so that it becomes necessary to add sulphurous 
 acid or acid sulphite of sodium, in order to reduce it to arsenious acid. Another 
 mode of proceeding, recommended by Odling (loc. cit.\ is to mix the suspected sub- 
 stance with strong hydrochloric acid, distil to dryness and test the distillate. In this 
 case the addition of sulphurous acid is unnecessary. 
 
 Bloxam's electrolytic process is of recent introduction and has not, so far as we are 
 aware, been yet applied in judicial investigations ; but it appears to present several 
 advantages over that of Marsh, especially in securing, by the addition of hydrosul- 
 phuric acid to the liquid, the complete separation of arsenic and antimony, the former 
 being then evolved as arsenetted hydrogen, the latter remaining wholly in the liquid. 
 The certainty of this separation is of especial importance in the investigation of cases 
 of poisoning by arsenic, inasmuch as tartar-emetic is often given in such cases to pro- 
 duce vomiting. 
 
 In all processes of testing for arsenic, it is of the utmost importance to ensure that 
 the indications obtained of the presence of that substance do not proceed from the 
 reagents themselves. Arsenic is very widely diffused in the mineral kingdom, and 
 hence it is by no means an easy matter to procure reagents absolutely free from it. 
 Sulphuric acid, hydrochloric acid, and zinc are often contaminated with it, and con- 
 sequently Marsh's process, in which these reagents are employed, is very liable to give 
 incorrect indications, unless the precaution be taken of testing the reagents in the 
 manner already described (p. 362) before introducing the suspected liquid. Sul- 
 phuretted hydrogen, evolved by the action of dilute sulphuric acid on sulphide of 
 iron often contains arsenic, proceeding from one or both of the substances used ; but 
 that which is evolved by heating native sulphide of antimony with hydrochloric acid 
 is generally free from it, because sulphide of arsenic, even if present in the sulphide of 
 antimony, is not decomposed by hydrochloric acid. The complete destruction of organic 
 matter by the processes described at page 366, requires the use of considerable quantities 
 of sulphuric or hydrochloric acid ; consequently the arsenic contained in the acid is 
 likely to accumulate in the resulting liquid in sufficient amount to make itself visible 
 in the subsequent examination, even though the proportion of it contained in the acid 
 may be too small to be perceptible in the comparatively small quantities required for 
 the actual testing. This consideration tends rather to induce a preference for methods 
 which do not require so complete a destruction of the organic matters, such as Eeinsch's 
 or the electrolytic process. 
 
 Quantitative Estimation of Arsenic. When arsenic is contained in a solu- 
 tion entirely in the form of arsenic acid, it is best to precipitate it in the form of 
 arsenate of magnesium and ammonium, AsMg 2 (NH 4 )O 4 + 6H 2 0, by mixing the 
 solution with excess of ammonia, and then with sulphate of magnesium, adding also a 
 quantity of chloride of ammonium sufficient to prevent the precipitation of hydrate of 
 magnesia by ammonia. The liquid is left to stand for some hours, and the precipitate 
 is collected on a weighed filter, and washed with water containing ammonia. It may 
 then be dried, either in vacuo or sulphuric acid, in which case it retains all its water 
 of crystallisation ormore expeditiously at 100 C., in which case it loses i| of its water, 
 and is reduced to AsMg 2 (NH 4 )0 4 + iH 2 0, or rather 2[AsMg 2 (NH 4 )0 4 ] + H 7 0, from 
 which the quantity of arsenic is easily calculated. 
 
 If arsenic exists in solution in the form of arsenious acid, it may either be brought 
 to the state of arsenic acid by oxidation with nitric acid, and the arsenic determined 
 as above, or the arsenic may be precipitated as trisulphide by hydrosulphuric acid, 
 the solution being previously acidulated with hydrochloric acid, and the precipitate 
 collected on a weighed filter, washed and dried at a temperature a little above 100 C. 
 If the trisulphide were quite pure and definite, its quantity might be at once deter- 
 mined by deducting the weight of the filter from the gross weight, and the quantity 
 of arsenic calculated from the formula As z S 8 . But, as the precipitate almost always 
 contains free sulphur, the quantity of arsenic in it must be estimated by oxidising the 
 sulphur with strong nitric acid, and proceeding in a manner exactly similar to that 
 which has been described for the estimation of antimony (p. 321). 
 
 Arsenious acid may also be estimated by its reaction with trichloride of gold, which 
 converts it into arsenic acid, and at the same time yields a precipitate of metallic 
 gold, every 4 at. of gold corresponding to 3 at. arsenious acid: 
 
 4 Audi" + 6H 2 + 3As'-0 = 4Au + 12HC1 + 3As 2 5 . 
 
368 ARSENIC : ESTIMATION AND SEPARATION. 
 
 The gold solution used for the purpose is the sodio-chloride or ammonio-chlorido 
 (see GOLD) : it must be free from nitric acid. 
 
 When arsenious and arsenic acids exist together in solution, the latter may be pre- 
 cipitated as ammonio-magnesian arsenate (a considerable quantity of chloride of 
 ammonium being added to prevent the simultaneous precipitation of the arsenious 
 acid) ; the arsenious acid in the filtrate is converted into arsenic acid by oxidation 
 with chlorate of potassium and hydrochloric acid, and then precipitated in the 
 same manner ; or the arsenious acid may be estimated by chloride of gold, as just 
 described. 
 
 Atomic Weight of Arsenic. Berzelius (Schw. J. xxxiii. 172) determined the 
 atomic weight of arsenic from the quantity of sulphurous anhydride produced by heat- 
 ing arsenious oxide with sulphur. The equation, 2As 2 3 + S 9 = 2As 2 S 3 + 3S0 2 , 
 shows that 1 at. As 2 s , yields 1| at. SO 2 . Now in an experiment made by Berzelius, 
 2-203 grm. As 2 3 gave 1-1069 SO 2 . Therefore: 
 
 . 96 = m-84 
 
 and deducting s = 48, there results As 2 = 149-84 and As = 74-92. Pelouze 
 (Compt. rend. xx. 1014) decomposed pure trichloride of arsenic with water, and de- 
 termined the quantity of hydrochloric acid produced by means of a standard solution 
 of silver. His results (calculated with the atomic weights of silver and chlorine now 
 adopted (Ag = 108 ; Cl = 35-5), give as a mean of three experiments, As = 75*08. 
 The mean between this number and that of Berzelius is exactly 75. 
 
 Separation of Arsenic from other Elements. From other metals of the 
 second and third groups (ANALYSIS, INORGANIC), and from all non-metallic elements, 
 excepting selenium, arsenic is separated by precipitation with hydro-sulphuric acid 
 gas in acid solutions. From those metals of the first group whose sulphides are in- 
 soluble in alkaline sulphides, lead, copper, silver, &c., it is separated by precipitating 
 with hydrosulphuric acid, digesting the precipitate with sulphide of ammonium, 
 and acidulating the filtered solution with hydrochloric acid. From selenium and 
 tellurium, it is separated by sulphurous acid, which precipitates those elements from 
 their solutions in the free state. 
 
 Separation from Antimony. When arsenic and antimony exist together in the form 
 of an alloy, they may be completely separated by heating the compound to low redness 
 in a stream of carbonic anhydride, the arsenic then volatilising and the antimony re- 
 maining. Antimony is, however, the only metal from which arsenic can be completely 
 separated in this manner ; if the alloy contains any other metal, some of the arsenic 
 will be retained, and the method is no longer applicable. When this is the case, the 
 alloy may be dissolved in hydrochloric acid, to which nitric acid or chlorate of potas- 
 sium is gradually added ; the solution diluted with water after addition of tartaric 
 acid, is then mixed with a considerable quantity of chloride of ammonium and excess 
 of ammonia, and the arsenic precipitated by addition of sulphate of magnesium. The 
 antimony may then be precipitated from the filtrate by hydrosulphuric acid. This 
 mode of separation is equally applicable when the two metals are in the state of 
 sulphides ; as, for instance, when they are precipitated together from solution by hydro- 
 sulphuric acid. When they occur together as oxides, they may be dissolved in hydro- 
 chloric acid, mixed with tartaric acid, and treated as above ; or they may be separated 
 by fusion with caustic soda in the manner to be presently described. 
 
 The separation of arsenic from tin may be effected by converting the two metals 
 into sulphides, and separating them, after drying and weighing the whole, by ignition 
 in a stream of hydrosulphuric acid gas. The mixed sulphides are introduced into a 
 weighed glass bulb, having a tube attached to it on each side. One of these tubes, 
 the exit-tube, must be at least a quarter of an inch in diameter, to prevent stoppage, 
 and bent downwards so as to dip into a flask containing ammonia. The whole is 
 then weighed, hydrosulphuric acid gas passed through the apparatus, and the bulb 
 heated till the whole of the sulphide of arsenic is sublimed. Part of the sulphide of 
 arsenic passes into the ammoniacal liquid, by which it is dissolved, and the rest 
 sublimes in the wide tube. When the operation is ended, and the apparatus has 
 cooled, the wide tube is cut off at a short distance from the bulb, then broken, and 
 the pieces digested in caustic potash to dissolve out the sulphide of arsenic. The 
 solution thus obtained is added to the ammoniacal liquid in the flask ; the sulphide of 
 arsenic is precipitated by hydrochloric acid, and oxidised, without previous filtration, 
 with hydrochloric acid and chlorate of potash ; and the resulting arsenic acid is pre- 
 cipitated by ammonia and sulphate of magnesium. The sulphide of tin remaining in 
 the bulb is converted into stannic oxide by treating it with strong nitric acid. 
 
 Separation of Arsenic from Antimony and Tin together. The separation of these 
 
ARSENIC: ESTIMATION AND SEPARATION. 369 
 
 three metals is attended with considerable difficulty. The best mode of effecting it 
 is to convert them into arsenate, antimonate, and stannate of sodium, and treat the 
 mixture with dilute alcohol of a certain strength, which dissolves the arsenate and 
 stannate of sodium, and leaves the antimonate undissolved. 
 
 If the three metals exist together in solution, they are precipitated as sulphides by 
 hydrosulplmric acid, and the sulphides are fused in a silver crucible with a mixture 
 of nitre and caustic soda ; or, better, they are oxidised by heating them with strong 
 nitric acid ; and the solution, together with the insoluble stannic and antimonic acids, 
 is mixed with excess of caustic soda and evaporated to a small bulk, then transferred 
 to a silver crucible, evaporated to dryness, and fused for some time at a red heat. 
 The fused mass, consisting of arsenate, antimonate, and stannate of sodium, is disin- 
 tegrated by digestion in warm water, the contents of the crucible are transferred to a 
 beaker glass, and the crucible is well rinsed out with a measured quantity of water. 
 The greater part of the arsenate and stannate of sodium then dissolves, while the 
 antimonate remains undissolved. But to effect complete separation, a quantity of 
 alcohol of specific gravity 0-833, is added equal in bulk to one-third of the water used ; 
 the mixture is left to stand for 24 hours and frequently stirred ; and the antimonate of 
 sodium, which has then completely settled down, is collected on a filter and washed, 
 first with a mixture of 1 vol. of the same alcohol and 3 vols. water ; then with 1 vol. 
 alcohol to 2 vols. water ; next with a mixture of equal measures of water and alcohol ; 
 and, lastly, with 3 vols. alcohol to 1 vol. water. 
 
 The antimonate of sodium, separated by this process, is digested in a mixture of 
 hydrochloric and tartaric acids, which dissolves it completely ; the antimony is then 
 precipitated by hydrosulphuric acid, and its quantity estimated in the manner already 
 described (p. 320). 
 
 The filtrate containing the arsenate and stannate of sodium is supersaturated with 
 hydrochloric acid, which throws down a bulky precipitate of stannic arsenate ; hydro- 
 sulphuric acid gas is passed through the liquid till the white precipitate is completely 
 converted into a brown mixture of the sulphides of tin and arsenic ; the whole is left to 
 stand till the odour of hydrosulphuric acid is no longer perceptible ; the precipitate is col- 
 lected on a weighed filter ; and the filtrate is heated for some time to expel the greater 
 part of the alcohol, then mixed with sulphurous acid, and again treated with hydrosul- 
 phuric acid, whereby a small quantity of sulphide of arsenic is generally precipitated. 
 This quantity of sulphide of arsenic being qxiite free from tin, need not be added to the 
 mixed sulphides on the filter. These mixed sulphides are dried at 100 C., their total 
 weight determined, and a known quantity heated in a stream of hydrosulphuric acid 
 gas in the manner described at page 368. The residual sulphide of tin is then con- 
 verted into stannic oxide, and the sublimed sulphide of arsenic, together with the 
 small quantity separately precipitated, is converted into arsenic acid by treatment 
 with hydrochloric acid and chlorate of potassium, and the arsenic precipitated as am- 
 monio-magnesian arsenate. (II. Rose, Analyt. Chem. 1851, ii. 229.) 
 
 This method is long and tedious, but gives accurate results. The most troublesome 
 part of it is the disintegration of the fused mixture of the sodium-salts, which is very 
 hard. To obviate this inconvenience, Professor Williamson dissolves the precipitated 
 sulphides of the three metals in a mixture of sulphide of sodium and caustic soda, 
 and mixes the solution with hypochlorite of sodium. The sulphides are thereby con- 
 verted into arsenic, antimonic, and stannic acids, which combine with the soda, and 
 may be separated by treatment with dilute alcohol as above. 
 
 If the three metals are in the state of solid oxides, the mixture may be dissolved in 
 hydrochloric acid, with addition of tartaric acid, and the metals precipitated as 
 sulphides as before. If the metals are mixed in the form of an alloy, they may be 
 dissolved in aqua-regia, the solution mixed with tartaric acid, then diluted, and pre- 
 cipitated in the same manner. 
 
 The method just described may, of course, be applied to the separation of antimony 
 from tin or arsenic alone. In these cases, however, the simpler methods above given 
 are preferable. 
 
 Bun sen has lately introduced a new method of separating arsenic from antimony 
 and tin, depending on the action of acid sulphite of potassium on the sulphides of 
 those metals. When recently precipitated trisulphide of arsenic is digested with 
 a solution of sulphite of potassium containing excess of sulphurous acid, it dissolves 
 at first ; but on raising the heat to the boiling point, the liquid becomes turbid from 
 deposition of sulphur, which, however, is dissolved for the most part by continued 
 boiling. Sulphurous acid is also given off, and the liquid contains arsenite and hypo- 
 sulphite of potassium : 
 
 *2As 2 S* + 16KHS0 3 = 4KAs0 2 + 6K 2 S 2 3 + 3S + 7S0 2 + 8H 2 
 
 Acid sulphite Arsenite of Hyposulphite 
 of potassium. potassium. ot potassium. 
 
 VOL. I. B B 
 
370 ARSENIC: ALLOYS. 
 
 The sulphide-s of tin and antimony arc not affected by acid sulphite of potassium. 
 Consequently, when a solution of these three sulphides in sulphide of potassium is 
 precipitated by a large excess of sulphurous acid, the liquid digested for some time 
 over the water-bath, and then boiled to expel the excess of sulphurous acid, the sul- 
 phides of tin and antimony remain undissolved, while the whole of the arsenic passes 
 into solution, and may be precipitated from the filtrate by hydrosulphuric acid. If 
 only sulphide of antimony is present in the residue, it may be washed with pure water ; 
 but disulphide of tin thus washed is sure to pass through the filter ; hence, if tin is 
 also present, the residue must be washed, first with a saturated solution of chloride of 
 sodium, and then with a slightly acid solution of acetate of ammonium to remove the 
 chloride of sodium ; after which it may be dried, the ammonium salt then volatilising. 
 The washing cannot be performed with acetate of ammonium alone, because arsenic is 
 never completely precipitated by hydrosulphuric acid from a solution containing 
 acetate of ammonium, that salt being in fact partly decomposed by hydrosulphuric 
 acid into free acetic acid and sulphide of ammonium, which retains the arsenic in 
 solution. Hence the liquid which runs through in washing out the chloride of sodium 
 by acetate of ammonium must not be added to the first wash-water containing the 
 arsenic. (Ann. Ch. Pharm. cvi. 8.) 
 
 Valuation of Arsenic Ores. To ascertain the amount of metallic arsenic that can 
 be obtained from an ore, the ore is gradually heated to redness in a retort or earthen 
 cylinder, either alone or, if it be a sulphide, with potash or quick lime. The greater 
 part of the sublimed arsenic may be collected on a thin iron plate rolled up and 
 inserted into the neck of the retort, and the rest on a cone of copper foil luted on to 
 the neck, a small aperture being left to allow the escape of gases. The sublimed 
 arsenic is then collected and weighed. Commercial arsenious acid may be assayed in a 
 similar manner by heating it with 16 to 20 per cent, of charcoal. 
 
 It is seldom required to ascertain the quantity of arsenious acid (anhydrous) that 
 an ore will yield by roasting. A more frequently occurring problem is to determine 
 the proportion of pure anhydrous arsenious acid contained in a crude product. If no 
 other volatile substances are present, the amount of the pure anhydrous acid may be 
 determined by sublimation in a retort ; in the contrary case, the arsenious acid may 
 be dissolved out by boiling water, and its amount ascertained by weighing the residue. 
 
 The quantity of pure sulphide which may be obtained from an ore, realgar, orpi- 
 ment, arsenical pyrites, &c., is found by sublimation. (Kerl's Huttenkunde, Bd. iii. 
 1* Abth. S. 2.) 
 
 ARSENIC, AXiZ<OYS OP. Arsenides. Arsenic unites by fusion with most 
 metals, forming alloys which are generally brittle. "With potassium and sodium it 
 forms alloys which give off arsenetted hydrogen gas when thrown into water. With 
 iron, zinc, and tin, it forms brittle compounds ; with copper, a white malleable alloy ; 
 with gold and silver, grey brittle alloys ; with lead and with antimony, hard, brittle, 
 very fusible compounds. It is introduced into the lead used in the manufacture of 
 shot, to prevent tailing, and cause the metal to run into regular globules. 
 
 Metallic arsenides heated out of contact of air, either retain the arsenic altogether 
 or give it up but partially. The alloys of arsenic and antimony are completely de- 
 composed by ignition at a moderate heat in an atmosphere of carbonic anhydride, the 
 arsenic volatilising and the antimony remaining. When an alloy of arsenic is heated 
 in contact with the air, part of the arsenic is evolved as arsenious oxide, while the 
 rest remains in the form of a metallic arsenite or arsenate. The arsenides of the 
 alkali-metals dissolve in hydrochoric or dilute sulphuric acid, with evolution of 
 arsenetted hydrogen ; the arsenides of heavy metals are little, if at all, attacked by 
 any acid, except nitric acid or aqua-regia. By fusion with nitre, metallic arsenides 
 are converted into basic arsenates ; when the arsenides of the heavy metals are fused 
 with nitre and an alkaline carbonate or hydrate, and the fused mass is treated with 
 water, the whole of the arsenic dissolves as arsenate of alkali-metal, and the heavy 
 metal remains in the form of oxide free from arsenic. Arsenides are not decomposed 
 by fusion with alkaline carbonates alone or mixed with charcoal, but if sulphur be 
 added, a sulpharsenite or sulpharsenate of the alkali-metal is formed, and the other 
 metal remains as sulphide free from arsenic. 
 
 Many metallic arsenides are definite compounds in atomic proportion, and in that 
 respect differ from the generality of alloys, which are mere mixtures of their constituent 
 metals in indefinite proportions. In this respect, as in some others, arsenic resembles 
 the metalloids rather than the true metals. The distinction is, however, not absolute, 
 as many of the metals proper form with one another alloys constituted in definite 
 atomic proportions. 
 
 Many metallic arsenides occur as natural minerals, e.g. copper-nickel, Ni 2 As, white 
 nickel pyrites, NiAs, tcsseral pyrites (Co; Ni; Fe) As, &c. 
 
ARSENIC : BROMIDE HYDRIDE. 37 1 
 
 Arsenide of Antimony, also called Allemontite, is found at Allemont, in the Chalanche 
 Mountains, department of Isere ; also at Andreasberg, Przibram, &c. ; occurring in 
 veins in gneiss, together with native antimony, antimony ores, and arsenical cobalt. It 
 forms fine-grained, spherical, and kidney-shaped masses, with uneven fracture. Specific 
 gravity 6'2. Hardness 3'5. It is of a tin-white colour, opaque, with a faint lustre, 
 and in general appearance more or less resembling native arsenic. It contains, accord- 
 ing to Kammelsberg's analysis, 37'9 per cent. Sb to 62'1 As, corresponding to 1 at. 
 Sb : 2*6 at. As [Sb = 120'3], whence it would appear that the two metals are not 
 combined in atomic proportions, but isomorphously mixed. 
 
 The other metallic arsenides will be described with the several metals. 
 
 ARSENIC, 33ROXVIIDE OP, AsBr 3 , is prepared by shaking arsenic in powder 
 into a retort filled with bromine vapour the bromide of arsenic being distilled from 
 the excess of arsenic ; also, according to Nickles (Compt. rend xlviii. 837), by treating 
 pulverised arsenic with a solution of bromine in sulphide of carbon : it then crystal- 
 lises from the solution. It forms a white crystalline mass, which melts at 20 
 25 C. to a pale yellow liquid, boils at 22 C., and in the fused state fumes but slightly 
 in the air : in contact with water it is converted partly into arsenious acid and hydro- 
 bromic acid, partly into oxybromide of arsenic (p. 385). 
 
 ARSENIC, CHLORIDE OP. Butter of Arsenic ; Caustic Oil of Arsenic, AsCl*. 
 This is the only known chloride of arsenic, and corresponds to arsenious oxide, As 2 s . 
 It is produced when finely divided arsenic is brought in contact with chlorine the 
 metal becoming ignited by the intensity of the combination. The same compound is 
 obtained by distilling a mixture of 1 part of metallic arsenic and 6 pts. of corrosive 
 sublimate ; also by distilling arsenious oxide with strong hydrochloric acid, or with 
 common salt and sulphuric acid in excess. A colourless, oily, and very heavy liquid 
 is obtained, which is decomposed by water into arsenious and hydrochloric acid ; if 
 the quantity of water is insufficient for complete solution, oxychloride of arsenic (p. 386) 
 is produced. It does not solidify even at 29 C. Boils at 132, producing a vapour 
 whose density is 6*3006 (Dumas). It evaporates in the air at ordinary temperatures, 
 producing white fumes of arsenious oxide. It is highly poisonous. 
 
 Ammonio-chloride of Arsenic, As 2 H 21 N 7 Cl = 2AsCP.7NH 3 (H. Rose, Pogg. Ann. 
 
 62 Hi.), or 2(NHAs.Cl).4NH 4 Cl.NH 3 (Pasteur, Ann. Ch. Pharm. Ixviii. 207). Dry 
 ammonia gas passed into chloride of arsenic is rapidly absorbed, forming a white solid 
 body, which is soluble in water and in alcohol, and crystallises therefrom without 
 alteration. It is decomposed by heat, and according to Pasteur, ammonia is first given 
 off, and then the residue volatilises completely, yielding a sublimate, in which cubes 
 of sal-ammoniac can be detected by the magnifying glass. It is decomposed by hot 
 water, ammonia being evolved, and arsenious acid and sal-ammoniac remaining in 
 solution. When cold water is poured upon it, it becomes heated, gives off ammonia, 
 and forms a solution, yielding by spontaneous evaporation six-sided tables, which 
 may be regarded as a compound of chloride of arsenammonium with arsenious oxide 
 
 and water, 2(NHAs.Cl).As 2 3 .4H 2 0. This compound treated with strong aqueous 
 ammonia is converted into a hard mass of long six-sided tables, consisting of mon- 
 ammonic arsenite, As(NH 4 )0 2 , which quickly decomposes in solution, and still more 
 quickly in the solid state, giving off the greater part of its ammonia. 
 
 ARSENIC, FIiUORIBE OP, AsF 3 , is produced by mixing 1 pt. of fluor-spar, 
 purified by ignition, with 1 pt. of arsenious oxide and 3 pts. of strong sulphuric acid 
 in a leaden retort, and heating the mixture till it boils. It is a transparent, colour- 
 less liquid, of specific gravity 273, very volatile, boiling at 63 C., and fuming strongly 
 in the air even, at ordinary temperatures. The vapour is about four times as heavy as 
 atmospheric air. A drop of the liquid coming in contact with the skin evaporates 
 almost instantly, but nevertheless produces a painful wound, which suppurates for a 
 long time like a burn. It attacks glass but slowly in a close vessel, but in contact 
 with moisture, it is decomposed, yielding arsenious acid and hydrofluoric acid, which 
 corrodes the glass. With water, it forms a clear liquid, which corrodes glass, but 
 scarcely attacks zinc or tin. 
 
 ARSEMTC, HYDRIDE OP. Arsenic contains two compounds with hydrogen, 
 one solid and the other gaseous. The solid arsenide of hydrogen is obtained by passing 
 an electric current through water, the negative pole being formed of metallic arsenic ; or 
 by dissolving arsenide of potassium or sodium in water. It is a brown powder, which 
 evolves hydrogen when heated in a close vessel, and burns when heated in the air 
 (Davy). From Soubeiran's analysis, it appears to be AsH 2 . 
 
 TRIHYDRIDEOF ARSENIC, ARSENETTED HYDROGEN, AsH 3 , a gas analogous 
 in composition to ammonia, is obtained: 1. By dissolving arsenide of potassium in 
 
 B B 2 
 
372 ARSENIC: HYDRIDE ORES. 
 
 water, the solid arsenide being formed at the same time. 2. By dissolving an alloy of 
 1 at. arsenic and 3 at. zinc or tin, in hydrochloric or dilute sulphuric acid : 
 
 AsZn 3 + 3C1H = AsH 3 + 3ClZn. 
 
 3. By dissolving zinc in hydrochloric or dilute sulphuric acid containing arsenioua 
 acid (p. 361.) 
 
 12Zn + = 2AsH + 3H'0 
 
 4. By dissolving zinc, tin, or iron in aqueous arsenic acid or in a mixture of that acid 
 with hydrochloric or sulphuric acid : 
 
 2AsH 3 4 + 16Zn = 2 AsH 3 + 8Zn 2 0. 
 
 This last mode of formation was first given by Scheele, and afterwards denied by 
 Fischer (Pogg. Ann. ix. 261), who stated that aqueous arsenic acid, if quite free 
 from arsenious acid, evolves nothing but hydrogen when treated with zinc. Gmelin, 
 however, obtained arsenetted hydrogen with perfectly pure arsenic acid and zinc. 
 (Handbook, iv. 264.) 
 
 5. By the electrolysis of arsenious or arsenic acid. (Bloxam, p. 361.) 
 
 The gas obtained by either of the above processes is never pure, but always mixed 
 more or less with free hydrogen. It may be collected over water, but the most 
 scrupulous care must be taken that not the smallest quantity be inhaled, as it is exces- 
 sively poisonous, and has proved fatal in more than one instance. 
 
 Arsenetted hydrogen is a colourless gas, which liquefies at 30 C., but does not 
 solidify even at 110 C. It has an extremely repulsive odour, and even when largely 
 diluted with air, produces nausea, giddiness, and oppression. Small animals are 
 instantly killed by it. It does not redden litmus. Its specific gravity, according to 
 Dumas, is 2'695 (air = 1). One volume of the gas contains 1| vol. hydrogen and vol. 
 vapour of arsenic : [f . 0-0693 -f . 10-39 = 2701]. 
 
 Arsenetted hydrogen is slightly soluble in water. It does not combine either with 
 acids or with bases. It decomposes the solutions of many of the metals which are 
 precipitated by hydrosulphuric acid, its hydrogen alone being oxidised, and the 
 arsenic precipitated in combination with the metal. Prom a solution of sulphate of 
 copper, for example, it throws down arsenide of copper, AsCu 3 : 
 
 2AsH 3 + 3S0 4 Cu 2 = 3S0 4 H 2 + 2AsCu s . 
 
 When a mixture of this gas with free hydrogen is placed over a solution of sulphate 
 of copper, the arsenetted hydrogen is completely absorbed and the hydrogen remains. 
 From the salts of silver, gold, and platinum, arsenetted hydrogen precipitates the 
 metals, and is converted into arsenious acid, which remains in solution, e. g. : 
 
 6N0 3 Ag + AsH 3 + 3H 2 O = 6Ag + 6N0 3 H 
 
 Nitrate of Nitric Arsenious 
 
 silver. acid. acid. 
 
 Arsenetted hydrogen is decomposed at a red heat into free hydrogen and metallic 
 arsenic. It burns in the air with a bluish-white flame, quite different in appearance 
 from that of pure hydrogen, forming water and arsenious acid, which rises in white 
 smoke, and is deposited in a white crust on a cold body, such as a piece of porcelain 
 held just above the flame ; but if the porcelain be held in the middle of the flame so as 
 to cool it partially, then the hydrogen is alone burnt, and the arsenic, being less 
 combustible is deposited on the porcelain in metallic spots (p. 362). This effect is pre- 
 cisely similar to the deposition of soot on a glass rod or other cold body held in the 
 flame of a candle. 
 
 ARSENIC GLASS. See ABSENT, SULPHIDES OF (p. 386). 
 
 ARSENIC, IODIDE OF. AsP. Arsenic and iodine unite when gently heated 
 together, the combination being attended with considerable evolution of heat. By 
 distilling 3 pts. of iodine with 1 pt. of metallic arsenic, in a retort having its bulb 
 immersed in a sand-bath, the iodide is obtained as an orange-coloured crystalline 
 sublimate having the lustre of gold. It may also be prepared, like the bromide, by 
 treating metallic arsenic with a solution of iodine in sulphide of carbon. It dissolves 
 in 3-32 pts. of boiling water, and the solution, if boiled down, leaves pure iodide of 
 arsenic ; but, if left to cool slowly, deposits crystals of a compound of arsenious oxide 
 with oxyiodide of arsenic (p. 368). The iodide may be recrystallised from boiling 
 alcohol, and is then obtained in shining lamina? of a fine brick-red colour. Iodide of 
 arsenic has been used in the treatment of cancer. 
 
 ARSENIC, LIVER OP. An old term for the alkaline sulpharsenites (p. 388). 
 
 AM.SENIC, ORES OF. (pp. 360, 370.) 
 
ARSENIOUS OXIDE. 373 
 
 ARSENIC, OXIDES OP. Arsenic forms two well-defined oxides, viz. the Tri- 
 oxide or Arsenious Oxide, As 2 s , or AsO 3 , and the Pentoxide or Arsenic Oxide, As 2 5 , 
 or AsO 5 . The black film which forms on the surface of the metal when exposed to the 
 air is by many supposed to be a suboxide, but it is more probably a mixture of metallic 
 arsenic with the trioxide. 
 
 ABSENIOUS OXIDE (or ANHYDRIDE), As 2 3 ; in the hy drat ed state, AKSENIOUS 
 ACID. This compound occurs native in the mineral arsenite oTarscnolitc (q. v.) which 
 forms capillary crystals investing ores of nickel, cobalt, &c. It is formed when arsenic 
 volatilises in contact with free oxygen, as when the metal is heated in a glass tube 
 through which a current of air is passing. 
 
 On the large scale, arsenious oxide is obtained as an accessory product in the roasting 
 of arsenical ores of tin, cobalt and nickel, and as a principal product in the roasting of 
 arsenical pyrites. The ores are sometimes roasted on the hearth of a reverberatory 
 furnace, where they are in direct contact with the flame, more generally in muffles 
 which are surrounded by the flame but prevent it from touching the material. The 
 latter method involves a larger consumption of fuel, but yields a purer product, inas- 
 much as when the flame comes in contact with the ore, the arsenious oxide produced 
 by the oxidation becomes mixed with carbonaceous matter, which, in the subsequent 
 sublimation, reduces a portion of the arsenic to the metallic state, and gives the product 
 a grey colour. 
 
 At Keichenstein, in Silesia, arsenious oxide is prepared from arsenical pyrites. The 
 ore reduced to powder, is roasted in a muffle-furnace, and the vapour of arsenious 
 oxide is made to pass into a condensing chamber, divided into partitions, where it is 
 deposited in the pulverulent state, as crude arsenic or poison-flour (Giftmehl). This 
 product is refined by sublimation in cast-iron pots, the tops of which are contracted 
 into cones, and terminate in pipes which also pass into a condensing chamber. Lastly, 
 the refined arsenious oxide is again sublimed at a higher temperature, and collects in 
 the upper part of the subliming vessel in the form of a glass (vitreous arsenious 
 oxide). 
 
 At Eibas, in Catalonia, arsenious oxide is obtained from arsenical pyrites by roasting 
 in a reverberatory furnace without muffles ; in other respects, the series of operations 
 is similar to that just described. At Andreasberg, in the upper Harz, argentiferous 
 native arsenic is roasted to extract the silver, and arsenious oxide is obtained as a 
 secondary product. It is also produced in large quantity in the roasting of tin 
 ores and cobalt ores at Altenberg in Saxony, and of tin ores in Cornwall. (See Ure's 
 Dictionary of Arts, Manufactures, and Mines, i. 185 ; Kerl's Hiittenkundc, iii. l te Ab- 
 theilung, S. 14.) 
 
 Properties. Arsenious oxide is a white solid, which occurs in two crystalline forms 
 and likewise in the amorphous state. 1. Amorphous, vitreous or glassy arsenious 
 oxide is produced, when the vapour condenses on a surface whose temperature is but 
 little below the volatilising point of the oxide, so that before solidifying it passes 
 through the semi-fluid state. It is transparent when first prepared, but gradually 
 becomes opaque, and passes into the crystalline state. Its specific gravity, according 
 to Grriibourt, is 3 "7 385. 2. Octahedral arsenious oxide* This variety is produced by 
 sublimation when the vapour is cooled so quickly that it solidifies at once, without pass- 
 ing through the semi-fluid state. A hot saturated aqueous solution deposits the 
 oxide in regular octahedrons on cooling. Vitreous arsenious oxide is transformed into 
 the octahedral variety by keeping, especially in contact with the air, and also by 
 solution in water or hydrochloric acid. When 2 or 3 pts. of the vitreous oxide are 
 dissolved in a mixture of 12 pts. of fuming hydrochloric acid and 4 pts. of water, 
 and the solution is left to cool slowly, the arsenious oxide crystallises in 
 transparent octahedrons, the formation of each crystal being accompanied by a flash 
 of light (IL Rose). The specific gravity of octahedral arsenious oxide is 2*695 
 (G-uibourt). 3. Right Rhombic Arsenious Oxide. This variety, which is isomorphous 
 with native oxide of antimony, is occasionally obtained by sublimation (Wohler), 
 also, according to Pasteur, when a boiling solution of potash is saturated with arsenious 
 acid and left to cooL It is converted into the octahedral variety by sublimation or 
 by solution in hot water. 
 
 Arsenious oxide volatilises at about 218 C., forming a colourless vapour of specific 
 gravity 13-85. The vapour is perfectly inodorous, provided the oxide has not been 
 heated in contact with charcoal or other reducing agent. The vitreous oxide may be 
 fused before it volatilises to any considerable extent; but the crystallised oxide 
 sublimes before fusion. Under pressure, the oxide may be melted to a glass. 
 
 Arsenious oxide dissolves but sparingly in cold water, more readily in boiling water, 
 the vitreous oxide dissolves more readily than the crystalline variety. A hot saturated 
 solution contains 1 pt. of the oxide or anhydrous acid in 10 or 12 pts. of water, and 
 
 B B 3 
 
374 ARSENIC: OXIDES. 
 
 on cooling deposits the greater portion, leaving a solution containing 1 pt. of flic 
 anhydrous acid in 30 pts. of water. The statements of different authors regarding- 
 the solubility of arsenious acid in water differ considerably, the discrepancy probably - 
 arising from the simultaneous occurrence of the vitreous and crystalline modification 
 in the acid submitted to experiment (Grm. iv. 257). No definite hydrate of arsenious 
 acid appears to exist. The aqueous solution is transparent and colourless, and slightly 
 reddens litmus. (For its behaviour with hydrosulphuric acid, nitrate of silver, and 
 other reagents, see page 361.) 
 
 Arsenious oxide dissolves in hot dilute acids more readily than in water, but separates 
 out completely on cooling, without forming any definite compound. It has therefore 
 little or no basic power. With tartaric acid, however, it forms a potassic double salt 
 analogous to tartar-emetic. (See TARTARIC ACID.) 
 
 It dissolves in at /call's, forming arsenites of alkali-metals. 
 
 It is nearly insoluble in alcohol, quite insoluble in ether. 
 
 Arsenious oxide, whether in the dry state or in solution, is one of the most violent of 
 the acrid poisons, a dose of two or three grains being certain to cause death, unless it 
 be very speedily ejected by vomiting, or rendered innocuous by conversion into an 
 insoluble compound. Nevertheless it appears to be possible, by commencing with 
 small closes and gradually increasing them, to accustom the human body to sustain 
 without injury, doses of 4 grains or even more ; and it is moreover stated, apparently 
 on good authority, that arsenic thus taken produces a plump and healthy appearance 
 in those who use it, and especially increases the power of the respiratory organs, and 
 consequently facilitates moiintain-climbing under heavy burthens. The Tyrolese 
 peasantry are said to swallow arsenic in considerable quantities for this purpose. 
 Those Avlio are accustomed to taking arsenic in this way, are also said to experience 
 great depression and loss of strength if they discontinue it. 
 
 Arsenious acid in small doses is much used in medicine, chiefly in cases of skin- 
 disease. The form in which it is most frequently administered is that of Fowler's 
 solution, which is an arsenite of potassium. 
 
 The best antidote to poisoning by arsenic is Jiydrated sesquioxide of iron, which, 
 when administered in excess, converts the arsenious acid into a basic ferric arsenite, 
 perfectly insoluble in water and in the fluids of the alimentary canal. It may be 
 prepared by precipitating a solution of ferric chloride or sulphate with ammonia, and 
 washing by decantation, and should then be kept under water, because when dry, its 
 power to lay hold of arsenious acid is very much diminished. It is most efficacious 
 when recently precipitated, the absorbing power being somewhat diminished, even by 
 keeping under water (Bunsen and Berthold, " Das Eisenoxyd ein Gegengift der 
 arsenigen Saure." Grottingen, 1834). Still more efficacious, according to Fuchs, is a 
 mixture of hydrated ferric oxide with magnesia, obtained by precipitating a solution of 
 ferric chloride or sulphate with excess of calcined magnesia. It should be prepared at 
 the time when it is wanted, and may be used at once, without washing, the soluble 
 magnesium-salt produced by the reaction being rather beneficial than otherwise, inas- 
 much as it exerts a purgative action. When ammonia is used as the precipitant, the 
 washing cannot be dispensed with, because arsenite of iron is somewhat soluble in 
 ammoniacal salts. The magnesia used for precipitating the ferric hydrate must not 
 be very strongly calcined. Magnesia itself is likewise capable of abstracting arsenious 
 acid from solution, and forming an insoluble compound with it ; but ferric hydrate is 
 more powerful in this respect, and the mixture of the two prepared in the manner just 
 mentioned, is more efficacious than either, probably because the ferric hydrate is 
 spread over the surface of the particles of magnesia in a state of fine division. 
 ( Handw. d. Clnm. 2 te Aufl. ii. 294.) 
 
 Arsenious oxide acts both as an oxidising and as a reducing agent. It partially de- 
 oxidises many compounds rich in oxygen, e.g. nitric acid, manganic acid, chromic 
 acid, hypochlorous acid, &c., being itself converted into arsenic oxide or acid. It 
 quickly reduces gold from the solution of the trichloride. Potassium, charcoal, sodium, 
 .<>*' [,l. H r, phosphorus, and zinc deoxidise it at a red heat, separating metallic arsenic. 
 I)i stilled with acetates, it yields cacodyl, a compound of 1 at. arsenic with 2 at. methyl, 
 As(CH 3 ) 2 , which may be recognised by its peculiar and intolerable odour. When 
 vapour of arsenious oxide is passed over red-hot lime, part off it is resolved into 
 metallic arsenic, which sublimes, and arsenic oxide which unites with the lime, forming 
 an arscnate (Wollaston), while another portion, greater as the heat is less, unites 
 directly with the lime, forming an arsenite (Simon). Heated with carbonate of 
 potassium, it likewise yields metallic arsenic and an arsenate (Gay-Lussac). As 
 an oxidising agent, arsenic oxide is used in the manufacture of glass, for the purpose 
 of converting protoxide of iron into sesquioxide, which yields less highly coloured glasses 
 I him the protoxide. 
 
 ARSEXITES. Arsenious acid unites with bar.es in several proportions, but the salts 
 
ARSENITES. 376 
 
 are not very stable, and have been but little examined. Those whose composition is 
 MAsO 2 or M 8 O.As 2 3 , are generally regarded as neutral ; and besides these there are 
 basic arsenites containing M 4 As 2 5 , or 2M 2 O.As 8 8 , and M 3 As0 3 , or 3M 2 0. As 2 3 , besides 
 acid salts.* Arsenious oxide dissolves in caustic potash or soda, but does not neu- 
 tralise the alkali ; the concentrated solutions are decomposed by the carbonic acid in 
 *he air, and yield, after a while, very large and well formed crystals of anhydrous 
 arsenious acid. The acid dissolves in ammonia more readily than in water, and 
 remains free from ammonia when the solution is evaporated. Lime, baryta, and stron- 
 tia, dissolve when boiled with water and excess of arsenious acid, and on adding lime-, 
 baryta-, or strontia- water in excess to the solutions, basic salts are precipitated in white 
 flocks. These precipitates dissolve in acids and in ammoniacal salts : hence arsenious 
 acid cannot be precipitated by the alkaline earths from solutions containing ammo* 
 niacal salts. The other arsenites are insoluble in water, and are obtained by precipi 
 tation. They dissolve in hydrochloric acid, and some of them in acetic acid, also in 
 sulphate, hydrochlorate, and nitrate of ammonium. 
 
 Solutions of the alkaline arsenites give a light green precipitate with cupric salts, 
 egg-yellow with nitrate of silver. Hydrosulphuric acid produces no precipitate unless 
 a stronger acid is present in excess ; but all arsenites when dissolved in hydrochloric 
 acid give a precipitate with hydrosulphuric acid ; and if the metallic base of the 
 arsenite is likewise precipitable by hydrosulphuric acid, a compound metallic sulphide 
 may be produced. 
 
 Most arsenites are decomposed by heat : some give off arsenious oxide, and leave the 
 base in the form of oxide : but the arsenites of the alkali-metals and the alkaline earth- 
 metals, give off metallic arsenic and leave a salt of arsenic acid (5As 2 3 = 3As 2 5 + 
 As 2 ). Arsenite of silver gives off arsenious oxide and leaves a mixture of metallic 
 silver and arsenate of silver ; arsenite of lead alone withstands a red heat without 
 decomposition, and arsenite of magnesium is but imperfectly decomposed (Simon, 
 Pogg. Ann. xi. 435). Arsenites heated with charcoal give off metallic arsenic. 
 
 Arsenite of Ammonium, NH 4 As0 2 , or (NH l ) 2 O.As 2 3 , according to Pasteur; 
 (NH 4 ) 4 As 2 5 , or 2(NH 4 ) 2 O.As 2 3 , according to Stein, is produced, according to Pasteur, 
 when very strong aqueous ammonia is poured upon arseiiious oxide, and forms a 
 hard mass composed of microscopic six-sided tables belonging to the trimetric system. 
 It exists only in contact with ammonia, quickly giving off ammonia in contact with 
 the air. It forms a yellow precipitate with silver-salts, the solution turning acid. It 
 is insoluble in alcohol and in ether. 
 
 Arsenite of Antimony. Produced by digesting metallic antimony with 
 aqueous arsenic acid, and is precipitated on diluting with water. It may also be ob- 
 tained as a transparent, fused, vitreous mass, by heating metallic arsenic with anti- 
 monic oxide. 
 
 Arsenite of Barium, BaAsO 2 , or Ba 2 O.As 2 3 , is obtained by mixing a solution 
 of chloride of barium with acid arsenite of potassium, separating after a few hours as 
 a gelatinous mass or in dendritic ramifications. In this state it is very soluble in 
 water, but becomes sparingly soluble after drying : the liquid decanted from the jelly 
 likewise yields the salt by evaporation, as a heavy sparingly soluble powder. The 
 gelatinous salt is probably a hydrate. A salt containing 2Ba'-O.As 2 3 + 4H 2 is ob- 
 tained, according to Stein, by dropping baryta-water into aqueous arsenious acid, as 
 long as a precipitate continues to form, and washing with dilute alcohol. It gives off 
 2 at. water at 100 C., and the rest at a higher temperature, arsenic, however, volatilising 
 at the same time. 
 
 A concentrated solution of arsenious acid is immediately precipitated by baryta- 
 water, a very dilute solution after some time only, or not at all (L. Gmelin). Arse- 
 nite of ammonium precipitates solution of chloride of barium after a while. 
 
 Arsenite of Calcium. The several arsenites of potassium, added to solution 
 of chloride of calcium, yield precipitates, but not of constant composition (Filhol). 
 The neutral salt, CaAsO 2 , is obtained, according to Simon, by precipitating chloride'of 
 calcium with ammonia saturated with arsenious acid ; the precipitate is increased by 
 adding excess of ammonia, but dissolves partially when washed with water. When, 
 on the other hand, an aqueous solution of arsenious acid is mixed with excess of lime- 
 water, a white heavy powder (2Ca 2 O.As 2 3 , with water) is precipitated, which is very 
 little soluble in water, somewhat more soluble in the presence of ammonia-salts, or of 
 chloride of potassium or sodium. According to Stein, the precipitate thus ob- 
 tained is a mixture of several basic salts, but on adding sufficient arsenious acid to 
 dissolve part of it, the residue consists of 3Ca 2 0.2As 2 3 + 3H 2 ; this salt gives off 
 1 at, water at 100 C., the rest at a temperature at which decomposition begins. 
 
 * If = 8, the formula are MO.AsO*, ZMO.AsO 3 , and3A/0.^0^ respectively. 
 B B 4 
 
376 ARSENIC: OXIDES. 
 
 According to Kuhn (Jahresb. f. Chem. 1852, 379), a boiling solution of arsenious 
 acid added to excess of lime-water throws down the salt, 3Ca 2 O.As 2 3 , or Ca a As0 3 . 
 
 Arsenite of Cobalt, 3Co 2 0.2As 2 3 + 4H 2 0, is obtained by quickly mixing 
 arsenite of potassium with a solution of chloride of cobalt containing a large excess of 
 sal-ammoniac. 
 
 Arsenite of Copper, Cu 4 As s 5 , or 2Cu 2 O.As 2 O s , is obtained by precipitating a 
 salt of copper with arsenite of potassium, or with arsenious acid and a sufficient quantity 
 of ammonia to neutralise the acid present (p. 361). It is a light green precipitate 
 (Scheele's green), which dissolves in excess of ammonia without colour, yielding a 
 solution of arsenic acid and cuprous oxide. Arsenite of potassium containing excess 
 of alkali dissolves it readily, with blue colour, but the solution quickly deccomposes 
 into arsenate of potassium and cuprous oxide. Vapour of arsenious oxide passed over 
 red-hot cupric oxide does not combine with it. 
 
 Aceto- Arsenite of Copper. 3CuAs0 2 .C 2 H 3 Cu0 2 . Schweinfurt Green, or Imperial Green. 
 This compound, the preparation of which is given at page 15, is much used as a pig- 
 ment, on account of its splendid green colour. A great deal of needless alarm has 
 lately been excited about the supposed deleterious effects of this pigment. It is ex- 
 tensively employed for staining wall-papers, and persons inhabiting rooms thus papered 
 are said to have had their health seriously deranged by the arsenical fumes evolved 
 from it ! Now it is utterly impossible that arsenic should volatilise from such a com- 
 pound at ordinary temperatures : it does not decompose at any temperature below 
 redness. The only way in which danger could arise from the use of paper stained 
 with an arsenical colour, is that particles of the compound might be brushed off in 
 in dusting the paper, and thus become mixed with the air of the apartment ; but it is 
 not in this way that the supposed accidents are said to have occurred ; the panic has 
 arisen from a mistaken notion as to the volatility of the arsenic. That the use of the 
 pigment is not really dangerous may be safely inferred from the fact that no bad 
 effects are experienced by the workmen engaged in its manufacture. (See Ure'a 
 Dictionary of Arts, Manufactures, and Mines, i. 157.) 
 
 Arsenite of copper forms a similar double salt with butyrate of copper. 
 
 Arsenites of Iron. There are several basic ferric arsenites. When recently 
 precipitated ferric hydrate is digested with a concentrated solution of arsenious acid, 
 in such proportion that the quantity of anhydrous ferric oxide present is equal to ten 
 times the weight of anhydrous arsenious acid, the acid is completely removed from the 
 liquid. With a smaller proportion of ferric oxide, the precipitation is nearly though 
 not quite complete. The products formed are basic arsenites containing 3Fe 4 3 .As 2 O 3 , 
 &c., from which part of the arsenious acid may be extracted by water. It is this 
 power possessed by hydrated ferric oxide of removing arsenious acid from a solution, 
 which renders it so useful as an antidote to arsenious acid (p. 374). 
 
 Arsenious acid, or arsenite of potassium, forms with ferric acetate an ochre-yellow 
 precipitate, which dries up to a brown mass containing 4Fe 2 3 .As 2 3 + 5Aq, and 
 when heated gives off water and the greater part of the acid (Bunsen), the whole, ac- 
 cording to Simon. Water removes part of the arsenious acid ; strong mineral acids 
 dissolves the salt completely. Ferric sulphate or chloride is not precipitated by free 
 arsenious acid : but gives with arsenite of potassium, according to Guibourt, a rusty- 
 brown precipitate, containing when dry, 2Fe 4 9 .As 2 3 + 7H 2 0. According to Damour, 
 this precipitate is slowly dissolved, with rusty-brown colour, by caustic potash, and 
 when slowly heated, melts before giving off arsenious oxide. A rusty yellow precipi- 
 tate, likewise containing 2Fe 4 3 .As 2 3 + 7H 2 0, is obtained by oxidising a solution of 
 ferrous sulphate with aqua-regia, neutralising with ammonia, and precipitating by soda- 
 ley, which has been saturated at the boiling heat with arsenious acid and freed from 
 the excess of that acid by cooling. It is soluble in caustic soda, and the solution, 
 evaporated to dryness, yields a red mass perfectly soluble in water. 
 
 Ferrous Arsenite, 2Fe*O.As 2 3 , is obtained by mixing ferrous sulphate with a solution 
 of arsenious acid in ammonia, as a greenish white precipitate, which becomes ochre- 
 yellow on drying. The non-oxidised compound is soluble in ammonia. 
 
 Arsenite of Lead. The neutral salt, Pb 2 O.As 2 3 , or PbAsO 2 , is obtained by pre- 
 cipitating neutral acetate of lead with acid arsenite of potassium, or with arsenious 
 acid (Filhol), or, according to Berzclius, with ammonia which has been saturated with 
 arsenious acid while warm ; the precipitate obtained by the latter process contains 
 water, becomes strongly electrical by friction, and when heated gives off some of its 
 acid and water, and melts to a yellowish glass. Neutral arsenite of lead is somewhat 
 soluble in water, insoluble in potash, but soluble in soda. The tctraplumbic -salt, 
 Pb 4 As s '0 5 ,or 2Pb 2 O.As 2 O 3 , is formed, according to Filhol, by precipitating neutral acetate 
 of lead with basic arsenite of potassium, or, according to Berzelius, by precipitating basic 
 acetate of lead with an ammoniacal solution of arsenious acid. It w a white hydrated 
 
ARSENITES. 377 
 
 powder, insoluble in water and in ammonia-salts, melting to a yellowish glass when 
 heated. According to Simon, it is obtained by passing the vapour of arsenious oxide 
 over red-hot oxide of lead, as a sulphur-yellow, easily fusible glass, which sustains a 
 considerable degree of heat without decomposing. A triplumbic salt, 3Pb 2 O.As 2 3 , 
 or Pb 3 As0 3 , is obtained by precipitating basic acetate of lead with a boiling solution 
 of arsenious acid. (Kuhn.) 
 
 Arsenite of Magnesium. Calcined magnesia, boiled with arsenious acid, takes 
 up a portion of it, but not in any definite amount. A precipitate of uncertain com- 
 position is obtained by mixing sulphate of magnesium with acid arsenite of potassium, 
 and heating. A solution of sulphate of magnesium is not precipitated by aqueous 
 arsenious acid ; but on adding a small quantity of ammonia, a copious precipitate is 
 formed which, according to Stein, has, after drying over sulphuric acid, the composition 
 Mg 3 As0 3 , or 3Mg'-O.As 2 3 . It is insoluble in ammonia, but dissolves in a large excess 
 of sal-ammoniac. (H.Rose.) 
 
 Arsenite of Manganese, 3Mn 2 0.2As 2 3 + 5H 2 0, is obtained, by treating a 
 manganous solution with arsenite of ammonium, as a rose-coloured precipitate, which 
 oxidises rapidly in the air, gives off 1 at. water at 100 C., and at a higher temperature 
 gives off arsenious oxide and metallic arsenic, leaving a residue of manganese and 
 manganous arsenate. 
 
 Arscnites of Mercury. The mercuric salt is obtained, by precipitating mercuric 
 nitrate with arsenious acid, as a white powder soluble in nitric acid. It dissolves also 
 in arsenite of potassium, and if the solution contains excess of potash, a black deposit 
 of reduced metal is immediately formed. The mercurous salt is obtained by double 
 decomposition, or by digesting mercury in arsenic acid, as a white precipitate soluble 
 in nitric acid. 
 
 Arsenite of Nickel. The salt 2Ni 2 O.As 2 3 is precipitated on adding arsenite of 
 potassium to a nickel-salt. A less basic salt, 3Ni 2 0.2As 2 3 + 4H 2 0, is produced, 
 according to Grirard (Compt. rend, xxxiv. 918), by quickly mixing a solution of 
 chloride of nickel containing a large excess of sal-ammoniac, with arsenite of potassium. 
 It is a greenish precipitate, which gives off 10 '3 per cent. (4 at.) water at 110C. 
 When heated in the air, it first gives off its water, and then yields a sublimate of 
 arsenious oxide, leaving yellow infusible arsenate of nickel : 
 
 3Ni 2 0.2As 2 3 + O 2 = 3Ni 2 O.As 2 5 4- As 2 3 . 
 
 Arsenite of nickel dissolves with violet colour in ammonia. It is converted by nitric 
 acid into arsenate ; by hydrochloric acid into arsenious acid and chloride of nickel. 
 
 Arsenite of Potassium. The neutral or monopotassic salt, KAsO 2 , orK 2 O.As 2 3 , 
 is obtained, by boiling the acid salt for some time with carbonate of potassium, and 
 agitating the residual salt several times with alcohol : it then remains as a syrupy 
 mass (Pasteur). Filhol was not able to prepare it pure. An acid salt, K 2 O.2As 2 3 + 
 2H 2 0, is obtained, by boiling potash-ley with excess of arsenious acid, whereby an alka- 
 line liquid is produced, which gives with silver-salts a yellow precipitate, 2Ag 2 O.As 2 :? , 
 mixed with arsenious acid, the liquid at the same time becoming acid. On mixing the 
 alkaline liquid with alcohol, it becomes thick and turbid, deposits after a few days 
 right rectangular prismatic crystals, adhering to the sides of vessel and after a longer 
 time solidifies completely to a saline mass. The salt gives off 1 at. water at 100 C., 
 whence it should perhaps be regarded as 2KHAs 2 4 + H 2 (Pasteur). The basic or 
 tctrapotassic salt, 2K 2 O.As 2 3 , is obtained by mixing the neutral salt with, excess of 
 potash-ley and precipitating by alcohol. It is very soluble in water, and yields with 
 silver-salts a yellow precipitate of the diargentic salt, 2Ag 2 O.As 2 8 , the liquid remain- 
 ing neutral. 
 
 Arsenite with Iodide of Potassium. A solution of iodide of potassium yields witli 
 arsenious acid or arsenite of potassium, a precipitate, 2KI.3As 2 3 , which is sparingly 
 soluble in cold water, dissolves in 19 pts. of boiling water, and decomposes at 315 C., 
 when heated with sulphuric acid (Emmet, Sill. Am. J. [2] xviii. 583). By passing 
 carbonic acid gas into a solution of this salt in a small quantity of boiling water mixed 
 with 3 or 4 times its volume of hot alcohol, and evaporating the resulting syrupy 
 liquid, a crystallised compound is obtained, consisting of 2KI . 3(K 2 O.H-'O.As 2 3 ), 
 or 2(KL3KAs0 2 ) + 3H 2 0. This salt is soluble in water and in alcohol, and reacts 
 with metallic salts like a mixture of iodide and arsenite of potassium. Strong sul- 
 phuric acid decomposes it, forming a red or yellowish precipitate of arsenious iodide. 
 The hot saturated solution of this salt deposits on cooling, nodular masses, or, when 
 carbonic acid gas is passed through it, a white powder, consisting of the salt 
 2KI.(K 2 O.H 2 O.3As 2 3 ), or 2(KI.KHAs 2 4 ).As 2 3 , which is sparingly soluble in 
 water, and when heated in a narrow glass tube, gives off vapour of water and metallic 
 
378 ARSENIC : OXIDES. 
 
 arsenic, together with arsenious oxide. No iodine is given off unless the air has 
 access to the salt. (E. Harms, Ann. Ch. Pharm. xci. 371.) 
 
 Arscnite of Silver. The tetr argentic salt, 2Ag 2 O.As 2 O s = Ag<As 2 5 , is formed 
 ns a yellow precipitate on treating solutions of silver salts with alkaline arsenites 
 (pp. 861, 375). It gradually turns dark grey when exposed to the air, blackens if exposed 
 to light. When heated, it gives off, according to Simon, first water, then arsenious 
 oxide, and leaves a mixture of arsenate of silver with metallic silver. 
 
 Another arsenite of silver is obtained, according to Filhol, as a light yellow pre- 
 cipitate on adding ammonia saturated with arsenious acid to an ammoniacal solution 
 of nitrate of silver. Between 140 and 150 C. it blackens suddenly, without loss of 
 weight, and at a higher temperature melts and gives off arsenious oxide. 
 
 It is easily soluble in acetic acid (whereby it is distinguished from phosphate of 
 silver) ; soluble also in potash. The latter solution is not precipitated by chloride of 
 potassium, but, on the contrary, is capable of dissolving an additional quantity of 
 chloride of silver. It slowly deposits metallic silver, while arsenate of potassium 
 remains in solution. When a solution of chloride of palladium or platinum is mixed 
 with arsenite of potassium, and then with arsenite of silver and potassium, the 
 platinum or palladium separates quickly in the metallic state. (Key no so.) 
 
 Scsqui-argentic Arsenite, 3Ag 2 0.2As 2 3 , or Ag 2 0.4(AgAs0 2 ), is produced as a white 
 precipitate, with evolution of ammonia, when nitrate of silver, mixed with a large 
 excess of nitrate of ammonium, is added by drops to arsenite of potassium. It is 
 blackened by light, dissolves in ammonia and in excess of arsenite of potassium, and 
 when heated blackens, yields a sublimate of arsenious oxide, and leaves a fusible 
 residue of a fine red colour. (E. Harms and others.) 
 
 Arsenite of Sodium. According to Pasteur, the sodium-salts of arsenious acid 
 correspond exactly to the potassium-salts, excepting that the acid salt does not crys- 
 tallise. Filhol did not obtain the neutral salt in a state of purity. 
 
 Arscnite of Strontium, SrAs0 2 +2H 2 0. Strontia- water is not precipitated 
 by aqueous arsenious acid in any proportion, even on boiling (Grmelin). Chloride of 
 strontium is precipitated by arsenite of potassium, but only after some days. The 
 precipitate gives off one-fourth of its water at 100 C. 
 
 A rscnitcs of Tin. Both the stannic and the stannous salts are white precipitates ; 
 the former is difficult to fuse. 
 
 ARSENIC OXIDE, As 2 O 5 , or As O 5 . In the hydrated state, ABSENicAci D. This 
 compound is produced by oxidising arsenious oxide or arsenious acid with nitric acid, 
 j'.qua-regia, hypochlorous acid, or other oxidising agents. 1. When 4 parts of arsenious 
 oxide are gradually added to 3 pts. of nitric acid of specific gravity 1-35, the mixture 
 becomes hot, and after 24 hours yields a syrupy liquid like strong oil of vitriol, consist- 
 ing of arsenic acid, still containing a little arsenious acid, which may be completely 
 oxidised by the addition of a small quantity of nitric acid. This process is used for 
 the preparation of arsenic acid on the large scale (E. Kopp). 2. Four parts of 
 arsenious oxide are heated with 1 pt. of hydrochloric acid, 12 pts. of nitric acid are 
 gradually added (Mitscherlich), and the resulting solution is evaporated to a syrup. 
 Both the oxidation and evaporation must be performed under a chimney having a 
 good draught, because part of the arsenic is converted into chloride, which escapes in 
 vapour. 3. Arsenic acid is also produced, together with hydrochloric acid, by passing 
 chlorine gas into aqueous arsenious acid. 
 
 Arsenic acid forms three hydrates analogous to those of phosphoric acid, viz. : 
 
 Monohydrate . . H 2 O.As 2 5 , or HAsO 3 
 
 Dihydrate . . 2H 2 O.As 2 5 , or H 4 As ! 7 = s O* 
 Trihydrate . . 3H 2 0. As 2 5 , or H 3 AsO* = ^ As( ^ 8 j O 3 
 
 The syrupy solution obtained as above, deposits, after standing for some time at 
 15 C. (60 F.), transparent, rather long prisms or rhomboidal laminae, containing 
 3H 2 O.As 2 5 + H 2 0, or 2H 3 AsO* + H 2 ; they deliquesce rapidly in the air, and 
 dissolve in water with great reduction of temperature. Both the water of crystallisa- 
 tion and the basic water may be expelled by heat. 
 
 The crystals heated to 100 C., first melt, and then yield the trihydratc, H 3 As0 4 , as 
 a crystalline precipitate. The same compound may be obtained in large transparent 
 crystals by exposing a concentrated solution of arsenic acid to a very low temperature. 
 
 * If = 8, the formulas are HO.AsO'\ '2110. AsO*, and ZHO.At>O'\ 
 
AKSENATES. 379 
 
 It dissolves easily in water, without reduction of temperature. The dihydrate, H 4 As z 7 , 
 which may be regarded as a compound of the mono- and tri-hydrates, is obtained by 
 heating the crystallised acid, 2H 3 As0 4 .H 2 0, for some time to 140 160 C.; it then sepa- 
 rates in hard shining crystals, leaving a mother-liquor of specific gravity 2 - 36 at 16 C. 
 It dissolves in water with moderate facility, but the solution is attended with great 
 rise of temperature. 
 
 The monohydrate, HAsO 3 , is formed by heating the before-mentioned crystals to 
 200, and at last to 206 C. ; the mass then suddenly becomes pasty, gives off a large 
 quantity of aqueous vapour, and is ultimately converted into a white nacreous sub- 
 stance consisting chiefly of the monohydrate; it dissolves slowly in cold water, 
 with moderate facility in warm water, producing great evolution of heat. (E. Kopp, 
 Ann. Ch. Phys. [3] xlviii. 196.) 
 
 Arsenic Oxide, Arsenic Anhydride, Anhydrous Arsenic Acid, Pentoxide of Arsenic, 
 As'-O 5 , is obtained by heating either of the hydrates to dull redness, and remains in 
 the form of a white mass, which has no action upon litmus ; is nearly insoluble in 
 water, and in ammonia ; and scarcely absorbs water from moist air, even in the course 
 of several days, deliquescing only after a long time. At a full red heat, it is resolved 
 into arsenious oxide and free oxygen. 
 
 The solutions of the three hydrates and of the anhydride exhibit exactly the same 
 characters ; they have a sour metallic taste, and all contain the trihydrate, the other 
 hydrates being immediately con verted into that compound when dissolved in water: in 
 this respect, the hydrates of arsenic acid differ essentially from those of phosphoric acid. 
 
 Arsenic oxide is reduced to the metallic state by charcoal, metals, cyanide of potas- 
 sium, Sfc., at a red heat, in the same manner as arsenious oxide. Aqueous arsenic acid 
 dissolves zinc and iron, with evolution of pure hydrogen ; but if sulphuric or hydro- 
 chloric acid is present, the arsenic acid is reduced, metallic arsenic, and solid arsenide 
 of hydrogen are deposited, and arsenetted hydrogen gas is evolved (p. 363). An electric 
 current passed through aqueous arsenic acid acidulated with sulphuric or hydro- 
 chloric acid eliminates arsenetted hydrogen, provided the solution does not contain 
 chlorides (Bloxam). Sulphurous acid reduces arsenic acid to arsenious acid, with 
 formation of sulpluu'ic acid. Hydrosulphuric acid slowly precipitates trisulphide 
 of arsenic, the action being assisted by heat, or by the presence of another acid. 
 Hyposulphite of sodium added to a solution of arsenic acid containing hydrochloric 
 acid, likewise throws down trisulphide of arsenic mixed with sulphur : 
 
 5Na-S 2 3 + 2H 3 AsO = As'S 3 + S 2 + 5Na 2 S0 4 + 3H 2 0. 
 
 Arsenic acid and its salts are very poisonous, but not in so high a degree as 
 arsenious acid and the arsenites (Wohler and Frerichs, Ann. Ch. Pharm. Ixv. 335). 
 A strong solution of arsenic acid placed upon the skin produces blisters like burns. 
 
 Arsenic acid is now extensively used in calico printing, in place of tartaric acid, for 
 developing white patterns on a coloured ground in the chloride-of-lime vat. 
 
 ARSENATES. Arsenic acid is a strong acid, expelling all the more volatile acids 
 from their salts at high temperatures. It is tribasic like ordinary phosphoric acid, 
 the general formula of its salts being M 3 As0 4 , in which 1 or 2 at. M may be replaced 
 by hydrogen. The solutions of the tri- and ^/-metallic salts, M 3 As0 4 , and M"HAsO ' ; 
 (sometimes called basic and neutral) have an alkaline or neutral reaction ; those of the 
 wwwo-metallic (or acid) salts, MH 2 As0 4 , have an acid reaction. The di- and mono- 
 metallic arsenates give off their water when heated, but take it up again on being dis- 
 solved in water : consequently there are no arsenates corresponding to the pyro- 
 and meta-phosphates. 
 
 The arsenates of the alkali-metals are soluble in water; of the others, only the 
 monometallic salts are soluble in water ; but the di- and tri-metallic salts dissolve 
 readily in free arsenic acid, and in the stronger mineral acids, less easily in acetic 
 acids : hence solutions of salts of the earth-metals and heavy metals are precipitated 
 by arsenate of potassium, but not by free arsenic acid. 
 
 The dimetallic arsenates of barium, strontium, and calcium, are insoluble in water, 
 but soluble in ammoniacal salts ; hence solutions containing arsenic acid together with 
 large quantities of ammoniacal salts are not precipitated by the salts of barium, 
 strontium, and calcium. When solutions of metallic salts are precipitated by a dime- 
 tallic arsenate of an alkali-metal, an insoluble trimetallic arsenate, M 3 AsO v , is often 
 formed, the liquid at the same time acquiring an acid reaction. 
 
 A solution of an arsenate in hydrochloric acid is slowly precipitated by sulphurcttul 
 hi/drogin, the precipitate consisting of trisidphide of arsenic and sulphur in the pro- 
 portion of the pentasulphide ; and if the metallic base of the salt is likewise thrown 
 down by sulphuretted hydrogen from :in acid solution, a precipitate is formed consist- 
 in" of a metallic sulph arsenate. A solution of an alkaline sulphide, with subsequent 
 
380 ARSENIC: OXIDES. 
 
 addition of hydrochloric acid, acts in the same manner as sulphuretted hydrogen. 
 An aqueous solution of an arsenate boiled with hyposulphite of sodium, deposits 
 trisulphide of arsenic and sulphur on addition of hydrochloric acid. Potash with- 
 draws from the insoluble arsenates the whole or part of the arsenic acid. 
 
 Solutions of the tri- and di-metallic arsenates of alkali-metal give white precipitates 
 with baryta- or lime-water, also with salts of bari^tm, strontium, calcium, the earth- 
 metals, manganese, zinc, and lead, also with stannous and ferric salts ; yellowish- 
 white with uranic and mcrcurous salts, yellow with mercuric-salts ; rose-coloured with 
 cobalt-salts, green with nickel-salts ; pale greenish blue with cupric salts ; light 
 brown withplatinic salts ; brown-red with silver-salts. These precipitates are for the 
 most part soluble in arsenic, sulphuric, hydrochloric, and nitric acid, and in ammoniacal 
 salts : arsenate of silver, however, is not soluble in ammoniacal salts. 
 
 Magnesium-salts mixed with sufficient chloride of ammonium to prevent precipita- 
 tion by ammonia, give with solutions of arsenates, a white crystalline precipitate 
 of arsenate of magnesium and ammonium, insoluble in aqueous ammonia and in 
 chloride of ammonium ; the latter character distinguishes it from the correspondin g 
 salt of arsenious acid (p. 377). Solutions of arsenates added to excess of molybdate 
 of ammonium containing nitric acid, form, when the liquid is heated, a bright yellow 
 precipitate of arseno-molybdate of ammonium. All arsenates dissolved in water or 
 in nitric acid, give with basic acetate of lead, a white precipitate of arsenate of lead, 
 which when ignited with charcoal, melts and is reduced, with abundant evolution of 
 metallic arsenic. The last three reactions afford very delicate tests for arsenic acid. 
 The reaction with uranic salts is also very delicate, being perceptible to the twenty- 
 thousandth degree of dilution. 
 
 The arsenates are isomorphous with the corresponding phosphates. 
 
 Arsenate of Aluminium, 2Al 4 3 .3As 2 5 , is obtained by double decomposition 
 as a white precipitate, easily soluble in free acid, tind remaining as a vitreous ma*s 
 when the solutions are evaporated. 
 
 Arsenate ef Ammonium. The triammonic salt, (NH 4 ) 3 As0 4 , is obtained by 
 supersaturating a strong solution of arsenic acid with ammonia, as a heavy soluble 
 powder, which, when slightly heated, is quickly converted into the following salt : 
 The diammonic salt, (NH 4 )MI.As0 4 , is formed in the manner just mentioned, and also 
 by saturating a strong solution of arsenic acid with ammonia till a precipitat^ begins 
 to form ; by leaving the solution to evaporate, it is obtained in prismatic crystals of 
 the trimetric system, which effloresce in the air, giving off half their ammonia, but no 
 water. When heated, it decomposes, yielding metallic arsenic, ammonia, water, and 
 nitrogen gas. Its solution has an alkaline reaction. The monammonic or add salt, 
 NH 4 .H 2 .As0 2 . is obtained by imperfectly saturating arsenic acid with ammonia. It is 
 deliquescent, very soluble in water, and separates from the solution by spontaneous 
 evaporation in square-based octahedrons. It is decomposed by heat like the preced- 
 ing. Its solution has a strong acid reaction. 
 
 Arsenate of Barium. The tribarytic salt, Ba 3 As0 4 , is obtained as a white 
 powder, nearly insoluble in water, by precipitating aqxieous arsenic acid with baryta- 
 water (Laugier), or better, by gradually dropping trisodic arsenate into chloride 
 of barium (Graham). The dibarytic salt, 2Ba 2 HAs0 4 , is obtained when a solution 
 of the disodic salt is added drop by drop to an excess of chloride of barium. If, on the 
 other hand, the arsenate of sodium is in excess, the precipitate formed is a mixture 
 of the di- and tri-barytic salts, while monobarytic arsenate remains in solution. The 
 di-barytic salt contains, according to Mitscherlich, \ at. water (2Ba 2 IIAs0 4 + H'-'O) ; 
 according to Berzelius, 2 at. It gives up its water at a red heat. In contact with 
 water, it is resolved into the monobarytic salt, which dissolves, and the tribarytic salt 
 which remains undissolved (Berzelius). The monobarytic salt, BalFAsO 4 , is ob- 
 tained by adding baryta- water to aqueous arsenic acid till a precipitate begins to form ; 
 also by treating the dibarytic salt with water, or better, by dissolving it in aqueous 
 arsenic acid, and leaving the solution to crystallise. If a very large excess of arsenic 
 acid be used, the solution evaporated nearly to dryness, and the mass treated with 
 water, there remains a white powder, consisting of an acid salt containing 
 Ba 2 0.3H 2 0.2As 2 5 + 2H 2 0, or 2BaH 2 As0 4 .As 3 5 + 3H 2 0. (Setterberg.) 
 
 Arsrnatc of ^Barium and Ammonium, Ba*(NH 4 )As0 4 + |H 2 0, is obtained by 
 mixing the dibarytic salt with ammonia (Baumann), and Ba(NH 4 )H0 4 , by mixing 
 a solution of nitrate of barium with arsenic acid (Mitscherlich); both salts are 
 formed as bulky precipitates, which become crystalline after a while. 
 
 Arsenate of Calcium. The dicalcic salt occurs native, as Haidingcrite, 
 2Ca 2 HAs0 4 + H*O, and Pharmacohte, 2Ca 2 HAs0 4 + 5H 2 0, and may be prepared 
 like the corresponding barium-salt. The mowcalcic salt is soluble, the tricaldc salt 
 
ARSENATES. 381 
 
 insoluble in water; the latter is obtained by precipitating chloride of calcium in 
 excess with trisodic arsenate. (Graham.) 
 
 Arscnate of Calcium and Ammonium, Ca 2 (NH 4 )As0 4 + 6H 2 0, is produced, accord- 
 ing to Wac'h (Schw. J. xii. 285), by mixing a hot solution of arsenic acid in excess 
 of ammonia, with nitrate of calcium, and crystallises on cooling in tables arranged 
 like steps; if the solutions are mixed cold, the salt is precipitated as a powder. Any 
 arsenious acid that may be present remains dissolved. Another salt Ca(NH 4 )HAs0 4 
 is obtained by adding ammonia in excess to a solution of dicalcic arsenate in nitric 
 acid, as a flocculent precipitate, soon changing to a mass of needle-shaped crystals. ^ If 
 only enough ammonia be added to precipitate a portion of the salt, and the remaining 
 liquid be left at rest, the same salt is obtained in crystals belonging to the regular 
 system : it is therefore dimorphous. (Baumann.) 
 
 Cerous Arsenate, 2Ce 2 O.As 2 5 (?), is a white powder insoluble in water, but 
 dissolving in arsenic acid as an acid salt, which dries up to a vitreous mass. 
 (Hisinger and Berzelius.) 
 
 Chromic Arsenate. Chromic salts yield with arsenate of potassium an apple- 
 green precipitate. 
 
 Ar -senates of Cobalt. The cobaltic salt is a brown precipitate, obtained by 
 adding arsenate of potassium to a solution of cobaltic hydrate in acetic acid. 
 
 Cobaltous Ar senate. The tricobaltous salt occurs in red crystals, as cobalt-bloom, 
 Co s As0 4 .4H 2 (Kersten), a secondary product formed by the weathering of cobaltine 
 (see COBALT-BLOOM) ; and is obtained artificially as a reddish powder by precipi- 
 tating cobalt-salts with trisodic arsenate. 
 
 A basic arsenate of cobalt, known in commerce as Chaux metaltique, is prepared : 
 T. T3y adding carbonate of potassium to a solution of cobalt-glance in nitric acid or 
 aqua-regia, as long as a white precipitate of ferric arsenate continues to form, then 
 filtering, and treating the filtrate with more carbonate of potassium to precipitate 
 cobaltous arsenate. 2. By fusing cobalt-glance with twice its weight of crude potash 
 and a little quartz-sand, exhausting the fused mass with water, which takes up sul- 
 phide of potassium, together with arsenic, iron, and potassium, and again fusing the 
 white regulus with potash, whereby a blue slag is obtained, which is used for the pre- 
 paration of smalt, and a pure regalus of arsenide of cobalt, which, by careful roasting, 
 is converted into the required basic arsenate. 
 
 The product obtained by either of these processes is a reddish powder, which dis- 
 solves in ammonia with bluish-red, or in hydrochloric acid with red colour. Caustic 
 potash extracts the arsenic acid and leaves a blue protoxide of cobalt, which, when 
 ignited with 1 or 2 pts. of alumina yields a fine blue pigment. 
 
 Oentele, by melting Chaux metallique, prepared in the wet way, in a porcelain fur- 
 nace, obtained a mass, the cavities of which contained deep blue prisms, yielding a 
 rose-coloured powder, easily soluble in acids, and consisting of 4Co 2 O.As 2 5 . 
 
 The dicobaltous salt is not known. The monocobaltous salt is obtained by evaporat- 
 ing in vacuo the solution of cobaltous hydrate in excess of arsenic acid. 
 
 Arscnate of Copper, Cu 3 As0 4 , is obtained as a green powder by precipitating sul- 
 phate of copper with disodic arsenate, the liquid at the same time becoming acid. If 
 the liquid, together with the precipitate, be mixed with a sufficient quantity of 
 ammonia to dissolve the precipitate, and the solution be then left to evaporate, crystals 
 are obtained, consisting of Cu(NII 4 ) 2 As0 4 + NH 4 .H.O, which are permanent in the 
 air at ordinary temperatures, but are decomposed by exposure to sunshine, or by a 
 temperature of 300 C., ammonia and water first passing off, and arsenious oxide sub- 
 liming at higher temperatures. 
 
 Several basic arsenates of copper occur as natural minerals, viz. 4Cu 2 O.As 2 5 , 
 occurring with 1 at. water as olivcnite, with 7H 2 as euchroite, and with 10H 2 O 
 as liroconite ; also 5Cu 2 O.As' J 5 , occurring with 2H 2 as crinite, with 5H 2 as 
 aphancse, and with 10H 2 as leirochroite (Kupferschauni). 
 
 Arsenate of Iridium. Brown precipitate formed on adding arsenate of sodium 
 to chloride of iridium, and heating. 
 
 Arsenates of Iron. A ferric arsenate, 2Fe 4 3 .3H 2 0.3As 2 5 + 9Aq, or/e 2 HAsO 4- 
 3Aq, is obtained by precipitating ferric chloride with disodic arsenate, as a 
 white powder, which turns red and gives off water when heated. At a red heat it 
 glows slightly, and acquires a more yellowish tint. It dissolves in hydrochloric and 
 in nitric acid, separating as a white powder on evaporation. It is insoluble in acetic 
 acid and in ammoniacal salts. Aqueous ammonia dissolves it immediately when recently 
 precipitated, slowly after drying. The solution when evaporated leaves a ruby-red, 
 transparent, fissured mass, consisting of ammonio-fcrric arsenate, soluble in ammonia, 
 but decomposed by pure water, which extracts arsenate of ammonium, together with 
 
382 ARSENIC : OXIDES. 
 
 the undecomposed portion of the salt, and leaves ferric arsenate. The ammouiacal 
 solution remains clear when mixed with ferrocyanide of potassium, but on addition of 
 an acid yields Prussian blue. When diferrous arsenate is oxidised with nitric acid 
 and ammonia is added in excess, a precipitate is formed consisting of Fe 4 3 .As 2 5 , or 
 /c 3 As0 4 , insoluble in ammonia. Potash in large excess extracts part of the acid, 
 leaving a compound of 7 pts. arsenic acid (anhydrous) with 79 pts. ferric oxide, corre- 
 sponding to the formula IGFe'O'.As'O 5 + 24IFO (B er z el i us). On heating this salt to 
 redness, bright incandescence takes place, but no arsenious oxide is given off. 
 
 Iron-cinder is a native ferric arsenate containing 2Fe 4 3 .As 2 O 5 + 12H-O; scorodite 
 is Fe 4 O 3 .As-0 5 + 4JTO or /e 3 As0 4 + 2H-0 ; cube-ore is a ferroso-fcrric arsenate = 
 Fe 2 O.Fe 4 3 .As 2 5 + 6H 2 ; pittizite or brown iron ore is a ferric arsenate, 2Fe 4 3 . 
 As 2 5 + 12H 2 0, combined, or perhaps only mixed, with ferric sulphate and water. 
 
 b. Ferrous Arsenate is obtained by precipitation as a white powder, which assumes 
 a dirty green colour when exposed to the air. 
 
 Arsenate of Lead. The triplumbic salt, Pb 8 As0 4 , is prepared by dropping a solu- 
 tion of a lead-salt into excess of disodic arsenate, or by digesting the diplumbic salt 
 with ammonia. "When heated, it turns yellow and cakes together, but does not melt. 
 Insoluble in ammonia and ammoniacal salts. A tetraplumbic salt, 2Pb 2 O.As 2 5 , or 
 Pb 4 As 2 7 , is precipitated on mixing a solution of nitrate of lead with arsenic acid, or 
 with less than the equivalent quantity of di-ammonic, dipotassic, or disodic arsenate. 
 It is a white crystalline powder, insoluble in water and in acetic acid, soluble in nitric 
 and in hydrochloric acid. 
 
 Arseno-chloride of Lead. In many varieties of pyromorphite, PbCl.SPbTO 4 , the 
 phosphorus is more or less replaced by arsenic. 
 
 Arsenate of Magnesium. The trimagnesic salt, Mg 3 As0 4 , is formed by preci- 
 pitating sulphate of magnesium with disodic arsenate, or by boiling the dimaguesic 
 salt for a long time with a strong solution of arsenate of sodium. The dimagnesic salt, 
 2Mg*HAs0 4 + 13H 2 (Graham), is formed as a white insoluble precipitate on mixing 
 the dilute solutions of 3 pts. sulphate of magnesium, and 5 pts. disodic arsenate. In the 
 recent state, it dissolves easily in nitric acid, but it is insoluble in acids after ignition. 
 The monomagncsic salt dissolves readily in water, and dries up to a gummy mass. 
 
 Arsenate of Magnesium and Ammonium, Mg'-(NH l )As0 4 + 6H O, is obtained 
 as a crystalline precipitate by adding arsenic acid strongly supersaturated with am- 
 monia to a solution of a magnesium-salt mixed with sal-ammoniac. At 100 C. it 
 gives off y| of its water (44'28 per cent.), together with ammonia and a certain portion 
 of arsenic. Like the corresponding phosphate, it is almost insoluble in water con- 
 taining ammonia, or in sal-ammoniac, and is therefore well adapted for the estimation 
 of arsenic acid, and for separating that acid from arsenious acid. (H. Kose, p. 367.) 
 
 An arsenate of Magnesium and Calcium, containing Ca 2 HAs0 4 .Mg 2 HAs0 4 + Ca 3 AsO'. 
 Mg 3 As0 4 + 5H 2 0, occurs native as picropharmacolite. 
 
 Arsenate of Magnesium and Potassium, Mg 2 KAs0 4 , is produced by fusing arsenate 
 of magnesium with excess of carbonate of potassium, and adding 1 at. hydrate 
 of potassium : it is easily decomposed by water. The corresponding sodium-salt is 
 obtained in like manner. 
 
 Arsenate of Manganese, Mn 2 HAs0 4 , is obtained by saturating arsenic acid with 
 recently precipitated carbonate of manganese. 
 
 Arsenate of Manganese and Ammonium, Mn 2 (NH 4 )As0 4 + 6H 2 0. Kcddish-white 
 precipitate, gummy at first, afterwards becoming crystalline : obtained like the corre- 
 sponding magnesium-salt. 
 
 Arsenates of Mercury. A mercuric arsenate is obtained as a yellow precipitate 
 on adding arsenic acid to mercuric nitrate, or arsenate of sodium to mercuric chloride. 
 The same yellow salt is produced, with volatilisation of arseuious oxide, when arsenic 
 oxide is heated with mercury. 
 
 Di-mercurous arsenate, 2Hg 4 O.IFO.As 2 5 + H 2 0, or Hhg 2 .H.As0 4 + |H 2 *, is 
 obtained by dropping mercurous nitrate into a strong solution of arsenic acid, as a 
 white precipitate, which turns red in drying. When, on the other hand, arsenic 
 acid or arsenate of sodium is added to the mercurous solution, a double salt of arsenate 
 and nitrate of mercurosum is first formed ; but it quickly decomposes, especially if 
 heated, assuming a yellow, orange, red, and ultimately purple tint. When either of 
 these precipitates is dissolved in warm nitric acid, and the acid is gradually neutralised 
 with ammonia, a black precipitate is formed, which turns red when heated for some 
 time. 
 
 Dimercurous arsenate is composed of fine needles, sometimes brown-red, sometimes 
 purple-red. When dried at 100 C., and then more strongly heated, it first gives off 
 
 * Hhg = Hg = 200. 
 
ARSENATES. 383 
 
 a little water, then mercury, and leaves yellow mercuric arsenate, which, at a higher 
 temperature, is resolved into mercury, arsenious oxide, and free oxygen. With cold 
 concentrated hydrochloric acid, it yields a solution of arsenic acid, and a residue of 
 calomel, which is resolved by boiling into mercury and soluble mercuric chloride. It 
 is converted into mercuric arsenate by boiling with nitric acid, but dissolves unchanged 
 in that acid when cold, the solution being precipitated by ammonia. It dissolves 
 slightly in aqueous nitrate of ammonium, and separates on evaporation with fine red 
 colour and crystalline structure. It is quite insoluble in water, acetic acid, and am- 
 monia. (Simon, Pogg. Ann. xli. 424.) 
 
 Monomercurous arsenate, HhgAsO 3 , or Hg 4 O.As 2 5 , is produced by boiling mercuric 
 oxide, or the di-mercurous salt, to dryness with aqueous arsenic acid, triturating the 
 dry mass when cold with water, washing the powder, and drying it over the water- 
 bath, whereby the whole of the water is expelled. It is white and amorphous, gives 
 off mercury at a red heat, and leaves mercuric arsenate, which then undergoes further 
 decomposition. By careful addition of potash, it is converted into the dimercurous 
 salt With hydrochloric acid and with boiling nitric acid, it behaves like the dimercurous 
 salt. In cold nitric acid it dissolves less abundantly than the latter, and on heating . 
 with gradual addition of ammonia, it yields a precipitate of the dimercurous salt. It 
 is insoluble in water, acetic acid, and alcohol. (Simon.) 
 
 A double salt, consisting of arsenate and nitrate of mercurosum, Hhg 4 As 2 7 .2HhgN0 3 
 is obtained, when water is carefully poured upon an equal volume of a strong solu- 
 tion of mercurous arsenate in moderately strong nitric acid, and an equal volume of 
 aqueous ammonia then added, without allowing the liquids to mix. The double salt 
 is then gradually deposited in white nodules and needles. If the mercurous nitrate be 
 mixed with a very small quantity of nitric acid, the compound is obtained in the form 
 of powder. (Simon.) 
 
 Arsenate of Molybdenum. Molybdous Arsenate is a grey precipitate, produced 
 by mixing molybdous chloride with arsenate of sodium. The precipitate redissolves 
 at first, but afterwards becomes permanent. 
 
 Arseno-inolybdic Acid. Arsenic and molybdic acids digested together yield a colour- 
 less acid solution, and a lemon-yellow basic salt, insoluble in water. The solution 
 evaporated to a syrup, yields colourless crystals, which when treated with alcohol, first 
 yield white flocks, and then dissolve. 
 
 Arseno-molybdate of Ammonium. On adding arsenic acid to a solution of molyb- 
 date of ammonium and heating to 100 C., a yellow precipitate is formed, similar to 
 that produced by phosphoric acid. It contains 7 per cent, arsenic, and appears to be 
 analogous to phospho-molybdate of ammonium. (See PHOSPHORIC ACID.) 
 
 Arsenate of Nickel, Ni 3 As0 4 , occurs as nickel-bloom, and is obtained by double 
 decomposition as an apple-green crystalline powder, insoluble in water, soluble in 
 arsenic acid and in other strong acids, also in ammonia ; from the latter solution 
 potash throws down hydrate of nickel free from arsenic. 
 
 Arsenate of Palladium. Light yellow precipitate obtained by heating to- 
 gether the solutions of neutral nitrate of palladium and arsenate of sodium. 
 
 Arsenate of Platinum. Light brown powder soluble in nitric acid, obtained by 
 precipitating platinic nitrate with arsenate of sodium. 
 
 Arsenate of Potassium. The tripotassic salt, K 3 As0 4 , is obtained, by mixing 
 aqueous arsenic acid or the neutral salt with potash-ley, and strong concentration, in 
 small needles, which deliquesce quickly in the air. The dipotassic salt, K 2 HAs0 4 , is a 
 deliquescent non-crystalline mass, produced by saturating arsenic acid with potash, or 
 by fusing arsenious oxide with hydrate of potassium. 
 
 The monopotassic salt, KH 2 As0 4 (Macquer's arscniJcalischcs Mittehalz), is prepared : 
 1. By deflagrating arsenious oxide with an equal weight of nitre, dissolving the fused 
 mass in water, and leaving the solution to crystallise. 2. By mixing aqueous 
 carbonate of potassium with such a quantity of arsenic acid, that the solution reddens 
 litmus-paper but the redness disappears as the paper dries, and then evaporating. 
 3. A mixture of potash-ley and arsenic acid neutral to vegetable colours, deposits the 
 monopotassic salt when partially evaporated, the alkaline dipotassic salt remaining in 
 solution (Mitscherlich). Monopotassic arsenate is isomorphous with the corre- 
 sponding phosphates of potassium and ammonium, and with monammonic arsenate. 
 The crystals have a specific gravity of 2'638 ; they are permanent in the air, and give 
 off but little water, even at 288 C., but at a red heat they melt, give off water, and are 
 converted into a thin liquid, which on cooling solidifies into a white mass, cracked in 
 all directions. They dissolve in 5 '3 pts. of water at 6 C., forming a solution of 
 specific gravity, I'll 34; they are much more soluble in hot water, but insoluble in 
 alcohol. The aqueous solution reddens litmus, but the redness disappears on drying. 
 
384 ARSENIC: OXIDES. 
 
 It does not precipitate the salts of barium, calcium, magnesium, or the other earth- 
 metals. 
 
 Arsenate of RJiodium. Yellowish-white precipitate formed by heating arsenate 
 of sodium with chloride of rhodium and sodium. 
 
 Arsenate of Silver. The tri-argentic salt, Ag 3 As0 4 , is the only one that can be 
 obtained by precipitating nitrate of silver with soluble arsenates ; it is a dark brown 
 precipitate which melts to a brown-red glass when heated, is converted into chloride of 
 silver by hydrochloric acid, dissolves in acetic acid and aqueous ammonia, and when heated, 
 in sulphate, nitrate and succinate of ammonium. It dissolves also in aqueous arsenic 
 acid, and the solution, if left to evaporate, deposits the monargentic salt, AgH 2 As0 4 . 
 Both this salt and the mother-liquor from which it has separated, are decomposed by 
 water, yielding the brown triargentic salt. 
 
 The triargentic salt treated with sulphuric acid yields by evaporation a double salt, 
 Ag 4 As'-'0 7 .Ag 2 S0 4 , which is decomposed by water and by dilute sulphuric acid. 
 (Setterberg.) 
 
 Arsenate of Sodium. The trisodic salt, Na 3 As0 4 + 12H 2 is prepared by fusing 
 1 at. of the disodic salt with carbonate of sodium, or by mixing the aqueous solution 
 of arsenic acid with excess of carbonate of sodium, and evaporating to a small bulk. 
 The salt then crystallises almost completely, the excess of soda remaining dissolved. 
 The crystals are right rhombic prisms permanent in the air ; they have an alkaline 
 taste, melt at 86 C., and dissolve in 3^ pts. of water, the solution as well as the 
 ignited salt absorbing moisture from the air. The disodic salt, Na 2 HAs0 4 + 12H 2 0, 
 separates from a solution of arsenic acid slightly supersaturated with carbonate of 
 sodium, and left to evaporate below 18 C., in large efflorescent crystals isomorphous 
 with ordinary phosphate of sodium. By leaving a more concentrated solution to 
 crystallise at 20 C. or above, crystals are obtained belonging to the monoclinic system, 
 containing 14 at. water, and not efflorescent. Both kinds of crystals give off the 
 whole of their crystallisation-water, at 200 C., melt easily at a higher temperature, 
 and give off their basic water, leaving the anhydrous salt, 2Na 2 O.As~0 5 , or Na 4 As 2 7 ; 
 this anhydrous salt, however, recovers its basic water when redissolved. According 
 to Setterberg, a salt with 26 at., water of crystallisation separates from a solution 
 cooled to C. 
 
 The monosodic salt, NaH 2 As0 4 , is formed when arsenic acid is added to carbonate 
 sodium till the solution no longer precipitates chloride of barium ; it crystallises out 
 after a while in the cold. It is more soluble than the disodic salt, and forms large 
 crystals isomorphous with the corresponding phosphate. 
 
 Arsenate of Sodium and Ammonium, Na(NH 4 )HAs0 4 + 4H 2 0, is obtained by mix- 
 ing the solutions of the di-ammonic and disodic salts, in crystals exactly resembling 
 those of the corresponding phosphate (microcosmic salt). When heated to redness, 
 they leave monosodic arsenate. (Mitscherlich.) 
 
 Arsenate of Sodium and Potassium, KNaHAsO 4 + 16H 2 0. (Mitscherlich). 
 Obtained by neutralising the monosodic salt with carbonate of potassium. The crystals 
 contain, according to Mitscherlich' s analysis, 43-88 per cent, water, the preceding for- 
 mula requiring 44 16 per cent. ; but as they appear to be ismorphous with the disodic 
 salt containing 14 at., L. G-melin (Handbook iv. 299) considers it probable that 
 they also contain the same quantity of water. 
 
 Arseno-fluoride of Sodium, Na 3 As0 4 .NaF + 1 2 H 2 0. Prepared by gradually in- 
 troducing a mixture of 1 pt. arsenious oxide, 4 pts. carbonate of sodium, 3 pts. 
 nitrate of sodium, and 1 pt. fluor-spar, into a red-hot crucible, and ultimately heating 
 to complete fusion. On boiling the fused mass with water and filtering, the double 
 salt crystallises out in regular octahedrons, exactly like common alum. They have a 
 specific gravity of 2*849 at 21 C., dissolve in 9-5 pts of water, at 25 C., and in 2 pts. 
 at 75 C. (Briegleb, Ann. Ch. Pharm. xcvii. 95.) 
 
 Arsenosulphate of Sodium. A solution of 3 at. Na 2 HAs0 4 , mixed with 1 at. sulphuric 
 acid, yields crystals containing Na 8 As G I9 .2Na 2 S0 4 , or 4Na 2 0.3As 2 5 + 2(Na 2 O.S0 3 ) ; 
 their solution slightly reddens litmus, but still turns turmeric brown (Mitscherlich). 
 By dissolving sulphate of sodium and disodic arsenate together in equivalent proportions, 
 or by heating anhydrous disodic arsenate in a current of sulphurous anhydride (half the 
 arsenic acid being then reduced to arsenious acid, which volatilises), and subsequent 
 recrystallisation, a salt is obtained, composed of Na 2 S0 4 .Na 4 As 2 7 , which does not 
 alter by exposure to the air, and fuses more easily than either of its component salts. 
 (Setterberg.) 
 
 Arsenate of Strontium, Sr 2 HAs0 4 . Resembles the barium-salt. By precipitat- 
 ing its solution in nitric acid with excess of ammonia, a double salt is produced contain- 
 ing Sr 2 (NH 4 )AsO + H 2 0. 
 
ARSENIC : OXYBROMIDE. 385 
 
 Ar senate of Thorinum, is obtained by double decomposition, as a white flocculent 
 precipitate, insoluble in water and in the aqueous acid. 
 
 Ar sen ate of Titanium. Arsenic acid added to solution of titanic oxide, throws 
 down white flocks, which dry up to vitreous masses, and are soluble in free titanic 
 acid, as well as in arsenic acid. 
 
 Arscnates of Tin. The stannic salt, 2Sn0 2 .As 2 5 + 10H 2 0, or (Sn) 2 As-0 9 .10H 2 0, 
 is precipitated as a gelatinous mass when a mixed solution of stannate and excess of 
 arsenate of sodium is treated with excess of nitric acid. It is transparent when dry, 
 and gives off all its water at 120 C. (Haeffely, Phil. Mag. [4] x. 290.) 
 
 Stannous Arsenate is a white precipitate obtained by adding arsenic acid to stannous 
 chloride or acetate. Tin heated with aqueous arsenic acid eliminates hydrogen and 
 forms a gelatinous mass. 
 
 Ar senates of Uranium. Urania arsenate, or Arsenate of Uranyl, (U 2 0) 2 HAs0 4 + 
 4H 2 0, is formed by precipitating uranic acetate with arsenic acid, or uranic nitrate 
 with arsenate of sodium. It is a yellow precipitate which gives off its water at 
 120 C. 
 
 A sodio-uranic nitrate, (U 2 0)NaAsO + |H 2 0, is obtained by mixing a solution^ of 
 uranic nitrate with trisodic arsenate ; and by boiling uranic arsenate with solution 
 of basic acetate of copper (obtained by digesting verdigris with water), a green cupro- 
 uranic arsenate is formed, containing (U 2 0).CuAs0 4 + 4Aq. (Werther.) 
 
 Uranous Arsenate, IPHAsO 4 + |H 2 0, is a green precipitate obtained by treating 
 uranous chloride with disodic arsenate. It dissolves in hydrochloric acid, and the 
 solution mixed with excess of ammonia yields a very bulky precipitate of tri-uranous 
 arsenate, U 3 As0 4 . (Rammelsberg, Pogg. Ann. lix. 96.) 
 
 Arsenates of Vanadium. A solution of vanadic hydrate in excess of arsenic 
 acid yields by evaporation, a crust of blue crystalline granules, containing 1 at. 
 vanadic oxide (VO) to 1 at. anhydrous arsenic acid. It dissolves very slowly in 
 water, but easily in hydrochloric acid. A more basic salt is obtained as a syrupy 
 mass, mixed with crystals of the preceding salt, by evaporating a solution of arsenic 
 acid saturated with vanadic oxide. 
 
 If the solution of the crystalline compound in nitric acid be evaporated till nitrous 
 acid begins to escape, a yellow powder is deposited, which is a compound of vanadic 
 and arsenic anhydrides, 2V 2 3 .3As 2 5 . 
 
 Arsenate of Yttrium. The di-yttric salt obtained by precipitation is a white 
 heavy powder, which dissolves in nitric acid, and separates therefrom in crystalline 
 grains. The nitric acid solution supersaturated with ammonia yields the tri-yttric salt. 
 Yttria dissolves in excess of arsenic acid, but the solution when heated deposits the 
 di-yttric salt. 
 
 Arsenate of Zinc. Acetate of zinc treated with arsenic acid or arsenate of 
 sodium, yields a white precipitate, which dissolves in excess of arsenic acid, and se- 
 parates on evaporation in cubical crystals of an acid salt. Zinc dissolves in aqueous 
 arsenic acid, with evolution of arsenetted hydrogen, and deposition of metallic arsenic 
 mixed with brown solid arsenide of hydrogen. When zinc and arsenic oxide are fused 
 together, a large quantity of arsenic is reduced, with slight detonation. 
 
 Trizincic Arsenate, Zn :t As0 4 + 4H 2 0, occurs as Kbttigite in the Daniel cobalt mine 
 near Schneeberg in Saxony, forming monoclinic crystals, or crusts with crystalline 
 structure. Specific gravity 8*1. Hardness 2'5 3. It is of light carmine or peach- 
 blossom colour, translucent, and gives a reddish- white streak. The zinc is partly 
 replaced by cobalt and nickel. Analysis 37'2 per cent. As 2 5 , 30'5 Zn0, 6-9 Co 2 O, 
 2-00 Ni 2 O, with trace of lime, and 23-4 water. (Kottig, J. pr. Chem. xlvii. 183; 
 Naumann, ibid. 256.) 
 
 Sulphate of zinc added to a solution of arsenate of sodium containing ammonia pro- 
 duces a precipitate of trizincic arsenate, which soon changes to a crystalline compound 
 containing, according to Bette, Zn 3 As0 4 .NH 3 .|H 3 (?) 
 
 Arsenate of Zirconium. White precipitate insoluble in water. 
 
 ARSETCTIC, OXYBROMIDB OP. Bromarsenious Add. AsErO. Arsenious 
 oxide dissolves easily and abundantly in fused arsenious bromide, forming a somewhat 
 viscid dark-coloured liquid, which does not solidify so quickly as the pure bromide. 
 If this liquid be distilled till it becomes rather thick and then allowed to cool to about 
 150 (C. or F. ?) it separates into two layers, the lower of which is a soft dark-coloiired 
 mass, consisting of the oxybromide AsBrO, while the upper, which is very viscid, is a 
 compound of the oxybromide with arsenious oxide, probably 6AsBrO.As 2 3 ; both these 
 bodies are decomposed by heat, giving off bromide of arsenic (W. Wallace, Phil. Mag. 
 [4] xvii. 122). An oxybromide of arsenic is likewise formed by the action of water on 
 
 VOL. I. C C 
 
386 ARSENIC: SULPHIDES. 
 
 the bromide (Serullas). When bromide of arsenic is boiled with a quantity of water 
 containing hydrobromic acid not sufficient to dissolve it, the undissolved portion is 
 converted into oxybromide. A cold solution of bromide of arsenic in water containing 
 hydrobromic acid, yields, by evaporation over sulphuric acid, thin white pearly crystals, 
 consisting of hydrated oxybromide, 2AsBr0.3H 2 0. A solution of bromide of arsenic 
 in water, prepared at the boiling heat, deposits on cooling crystals of arsenious oxide ; 
 but if the water contains a large quantity of hydrobromic acid, the solution deposits on 
 cooling ,white flocks of a compound, which after drying between filter-paper, consists 
 of 2AsBrC.3As 2 3 + 12H 2 0. When bromide of ammonium is added to a cold con- 
 centrated solution of bromide of arsenic, six-sided tables are slowly deposited, consisting 
 mainly of anhydrous bromide of arsenic. (Wallace, loc. cit.) 
 
 ARSENIC, OXYCHZ.ORIDE OP. Chlorarsenious Acid. AsCIO, or AsCl 3 . As 2 3 . 
 Pulverised arsenious oxide added in successive portions to boiling chloride of arsenic 
 continues to dissolve till the liquid contains 2 at. chloride to 1 at. oxide. The same 
 solution is obtained by passing dry hydrochloric acid gas into a vessel containing dry 
 arsenious oxide till the latter is dissolved : great heat is evolved during the reaction. 
 On distilling the solution obtained by either process, till it begins to froth, and leaving 
 the residue to cool, oxychloride of arsenic separates as a viscid, translucent, brownish 
 mass, which fumes slightly in the air, and absorbs oxygen from it, froths when strongly 
 heated, giving off chloride of arsenic, and at the subliming temperature of arsenious 
 oxide, leaves a hard vitreous residue, consisting of AsC10.As 2 3 . 
 
 Oxychloride of arsenic is likewise produced when chloride of arsenic is treated with 
 a quantity of water not sufficient to dissolve it completely. A solution of chloride of 
 arsenic in the smallest possible quantity of water (8H'-'0 to lAsCl 3 ) deposits, after 
 some days, small, white, needle-shaped crystals, grouped in stars or like prehnite, and 
 consisting of AsC10.H 2 ; the mother-liquor yields an additional quantity when mixed 
 with chloride of sodium. 
 
 Oxychloride of arsenic unites with metallic chlorides. By mixing aqueous chloride 
 of arsenic with a quantity of hydrochloric acid sufficient to prevent the separation of 
 oxychloride, and then adding a lump of sal-ammoniac, crystals of that salt separate 
 out at first, and after a few days, fibrous needles of the compound AsC10.2NH 4 01, 
 apparently containing | at. H 2 0, which is given off when the crystals are left over sul- 
 phuric acid. (Wallace Phil. Mag. [4] xvi. 358.) 
 
 ARSENIC, OXYIODIDE OP. As 8 I 2 O n = 2AsI0.3As 2 8 . A hot aqueous solu- 
 tion of arsenious iodide deposits, when concentrated by boiling, fine red needles of the 
 anhydrous iodide ; but if left to cool slowly, it deposits thin pearly laminae, which after 
 drying between bibulous paper, are composed of 2AsI0.3As 2 3 + 6H*0, and give off all 
 their water over sulphuric acid. They are decomposed by water, and when heated 
 yield a sublimate chiefly consisting of iodide of arsenic, while arsenious oxide remains 
 behind (Wallace, Phil. Mag. [4] xvii. 122). The formation of this compound had 
 previously been observed by Plisson and by Serullas and Hottot, who regarded it as 
 a compound of arseuious oxide with arsenious iodide. (Grm. iv. 282.) 
 
 ARSENIC, OXVSITIiPBIDE OP. See SUXPHOXARSENATE OF POTASSIUM 
 (p. 395). 
 
 ARSENIC, SULPHIDES OP. The sulphides of arsenic are more numerous 
 than the oxides. There are three well defined sulphides, AsS, As 2 S 3 , and As 2 S 5 [or 
 AsS 2 , AsS 3 , and AsS 5 , if S = 16], all of which act as sulphur- acids. The first two 
 occur as natural minerals, realgar and orpiment, and may also be obtained in the free 
 state by artificial processes ; the third is known only in combination. Besides these 
 compounds, there is a subsulphide, As I2 S (?), which remains as a brown powder when 
 the disulphide AsS is digested with caustic alkalis ; and, according to Berzelius, a per- 
 sulphide, AsS 9 , obtained in yellow crystalline scales, by mixing a solution of dipotassic 
 or disodic sulpharsenate with alcohol, and evaporating to about two-thirds ; but the 
 product thus obtained is most probably a sulpharsenate with excess of sulphur. When 
 arsenious oxide is fused with sulphur, sulphurous anhydride is evolved, and a sulphide 
 of arsenic containing excess of sulphur remains. On distilling this residue, sulphur 
 passes over, accompanied by a continually increasing quantity of arsenic. Much of 
 the ordinary sulphur of commerce is a compound of this nature. 
 
 BISULPHIDE OF ARSENIC. AsS. Realgar, Red Orpiment, or Ruby Sulphur ; 
 rothes Rauschgelb, Arsenic sulphure rouge, Risigallo ; Sandaraca of Pliny and 
 Vitruvius ; (ravSapaitri of Theophrastus and JDioscorid.es. In combination : HYPOSULPH- 
 AESENIOUS ACID. This compound occurs native as realgar, crystallised in oblique 
 rhombic prisms of the monoclinic system, having an orange-yellow or aurora-red 
 colour, resinous lustre, and more or less translucent: streak varying from orange- 
 red to aurora-red; fracture conchoi'dal, uneven; sectile. Specific gravity = 3'4 to 3 '6. 
 
ARSENIC: SULPHIDES 387 
 
 Hardness = 1'5 to 2. It is found accompanying ores of silver and lead, at Andreas- 
 burg in the Harz, Kapnik and Nagyag in Transylvania, Felsobanya in Hungary, 
 Joachimsthal in Bohemia, and Schneeberg in Saxony. At Tajowa in Hungary, it 
 occurs in beds of clay; at St. Gothard imbedded in dolomite; near Julamerk in 
 Koordistan ; also in the Vesuvian lavas, in minute crystals. Strabo speaks of a mine 
 of sandaraca at Pompeiopolis, in Paphlagonia. (Dana.) 
 
 Bisulphide of arsenic may be prepared by melting metallic arsenic with sulphur or 
 orpiment, or sulphur with arsenious oxide, in the required proportions. As thus 
 obtained, it is transparent and of a ruby-colour, easily fusible, and crystalline after 
 solidification from fusion. An impure product is prepared on the large scale by heat- 
 ing in a subliming apparatus a mixture of arsenical pyrites and iron-pyrites, -and 
 melting the product with arsenic or sulphur, according as a darker or lighter colour is 
 desired. This commercial product is amorphous, usually brown-red, opaque, and of 
 variable composition, generally containing arsenious oxide. It is used as a pigment, 
 though not so much now as formerly. 
 
 Bisulphide of arsenic burns in the air with a blue flame, forming sulphurous and 
 arsenious oxides. When, deflagrated with nitre, it produces a bright white light. 
 Indian white fire is a mixture of 24 pts. nitre, 7 pts. sulphur, and 2 pts. realgar. The 
 disulphide heated with nitric acid, yields arsenic acid and free sulpur. With strong 
 sulphuric acid, it forms sulphurous and arsenious acids. When it is digested in fine 
 powder with potash-ley, part dissolves and there remains a brown powder consisting 
 of As 12 S. (?) 
 
 HYPOSULPHARSENITES. These are sulphur-salts formed by the mixing of disulphide 
 of arsenic with basic sulphides. They are for the most part sparingly soluble in 
 water. The little that is known of them is due to the researches of Berzelius. 
 
 The ammonium-salt is deposited in small dark brown granules on the sides of a 
 closed vessel in which neutral sulpharsenite of ammonium is kept for a long time. It 
 absorbs ammonia-gas, but gives it off again on exposure to the air. 
 
 Hyposulpharsenite of Potassium. The colourless liquid obtained by boiling trisul- 
 phide of arsenic with moderate concentrated carbonate of potassium, deposits in the 
 course of 12 hours, brown-red flocks of the salt K 2 S.AsS, or K 2 AsS 2 . If this compound 
 be washed with a small quantity of cold water till it swells up to a jelly, and then 
 treated with more water, the greater part dissolves, forming a red solution of the salt, 
 3K 2 S.2AsS, and leaving an insoluble dark-brown powder consisting of K 2 S.4AsS, which 
 melts easily when heated, and solidifies on cooling to a transparent dark red mass. 
 The basic salt 3K 2 S.2AsS, remains perfectly soluble in water, even after complete 
 drying. 
 
 The sodium hyposulpharsenitcs resemble those of potassium. 
 
 Other hyposulpharsenites are obtained by precipitation. The barium and calcium 
 salts are red-brown ; the magnesium-salt is brown ; the manganese-salt dark red. 
 
 TEISULPHIDE OF ABSENIC, or ARSENIOUS SULPHIDE. In combination: 
 SULPHAESENIOUS ACID. As 2 S 3 , or As 8 s . Orpiment, Yellow Sulphide of Arsenic, G-elbes 
 Rauschgdb, Risigallum, Auripigmentum (Vitruvius); Arsenicum (Pliny); 'AporeWoi/ 
 (Dioscorides) ; ' 'AfyeviKov (Theophrastus). This sulphide occurs native in^ rhombic 
 prisms belonging to the trimetric system, easily splitting parallel to ooPoo into thin 
 flexible laminae. They are translucent, of lemon-yellow colour, inclining to orange-yellow, 
 with pearly lustre on the cleavage-faces, resinous elsewhere ; powder lemon-yellow ; 
 specific gravity 3-459 (Karsten), 3*48 (Mohs, Haidinger), 3*4 (Breithaupt). 
 
 Trisulphide of arsenic is obtained in the pure state by passing hydrosulphuric acid 
 gas into a solution of arsenious acid or an arsenite acidulated with one of the stronger 
 acids. As thus prepared, it has a fine lemon-yellow colour, becoming darker by heat, 
 and produces an orange-yellow powder: it melts easily and volatilises at a higher 
 temperature. 
 
 An impure trisulphide is prepared on the large scale by subliming 7 parts of pulve- 
 rised arsenious oxide with 1 pt. of sulphur. It always contains more or less oxide, 
 inasmuch as to convert that compound completely into trisulphide requires 7 '3 pts. of 
 sulphur to 10 pts. of the oxide : hence this preparation is much more poisonous than 
 the pure artificial sulphide or the native sulphide. It was formerly much used as a 
 pigment, under the name of King's yellow, but is now almost entirely superseded by 
 chrome-yellow. The arsenious oxide may be extracted from it by boiling with water, 
 or with dilute aqueous acids, or cream of tartar. 
 
 Arsenious sulphide is also used in calico printing, the pattern being printed with a 
 preparation containing arsenious acid, and then passed through water containing 
 hydrosulphuric acid. A solution of orpiment in potash-ley is used in dyeing as a de- 
 oxidising agent, especially for reducing indigo. A paste composed of slaked lime, 
 orpiment, and water, is employed by some nations as a depilatory for removing the 
 
 cc 2 
 
388 ARSENIC: SULPHIDES. 
 
 beard; but it is a dangerous preparation, and, according to Bottger may be re- 
 placed for this purpose by sulpliydrate of calcium. 
 
 Decompositions. 1. Arsenious sulphide, like all the other sulphides of arsenic, is 
 converted by oxidising agents into oxides of sulphur and arsenic. When it is fused 
 with acid sulphate of potasssum, sulphurous oxide (SO 2 ) is given off, and arsenite of 
 potassium remains mixed with neutral sulphate. 2. Exposed to the action of chlorine 
 gas, it becomes heated, and deliquesces to a brown liquid consisting of a sulphochloricle 
 of arsenic, As 2 Cl 8 S 3 (H. Eose). 3. The vapour of arsenious sulphide passed over red- 
 hot iron, silver, and other metals, is decomposed, yielding a metallic sulphide and 
 free arsenic, which, if the other metal is in excess, unites with it. 
 
 4: When the vapour is passed over red-hot lime, arsenic is separated, and arsenate 
 of calcium is produced, together with sulphide of calcium. 
 
 5. Arsenious sulphide heated with carbonate of potassium or sodium in a glass tube, 
 yields a mirror of arsenic, together with sulpharsenate and arsenate of the alkali- 
 metal. If the mixture is heated in an atmosphere of hydrogen, or with addition of char- 
 coal, the arsenical mirror is increased by the arsenic reduced from the arsenate ; the 
 Bulpharsenate remains undecomposed. (H. Kose, Pogg. Ann. xc. 565.) 
 
 6. When arsenious sulphide is heated in a test-tube with a mixture of alkaline 
 carbonate and cyanide of potassium, the whole of the arsenic is reduced, according to 
 Fresenius ; only part of it, according to H. Eose, because the sulphur-salt of arsenic 
 formed at the same time resists the action of the cyanide of potassium. Hence 
 arsenious sulphide fused with cyanide of potassium and excess of sulphur does not 
 yield any arsenical mirror. The formation of the mirror may also be prevented by 
 the presence of other easily reducible metals, which convert the arsenic into an 
 arsenide, and do not give it up. 
 
 7. When arsenious sulphide is boiled with the solution of an alkaline carbonate, and 
 the concentrated solution is filtered, a clear liquid is obtained, which deposits a brown 
 powder, consisting of hyposulpharsenite of the alkali-metal, while a sulpharsenate re- 
 mains in solution. A similar decomposition takes place when a soluble neutral sulph- 
 arsenite is treated with water. 
 
 8. Arsenious sulphide is readily dissolved by cold caustic potash, soda, or ammonia, 
 undergoing exactly the same decomposition as antimonious sulphide under similar 
 circumstances (p. 322), the oxygen of the alkali converting the arsenic into arsenious 
 acid, while the alkali-metal unites with the sulphur, and the basic sulphide thus 
 formed combines with the rest of the arsenious sulphide : 
 
 4As 2 S s + 5K 2 = 3(K 2 S.As 2 S 3 ) + 2K 2 O.As 2 3 
 
 On adding an acid to this solution, no sulphuretted hydrogen is evolved, but the whole 
 of the sulphur and arsenic are separated as arsenious sulphide : 
 
 3(K 8 S.As 2 S 3 ) + 2K 2 O.As 2 O s + 10HC1 =- 10KC1 + 5H 2 + 4As 2 S 3 
 
 SULPHA.ESENITES. Arsenious sulphide unites with basic metallic sulphides in three 
 different proportions, forming, with potassium, for example, the compounds 3K 2 S.As 2 S 3 
 or K 8 AsS 3 , 2K 2 S.As 2 S 3 or K 4 As 2 S 5 , and K 2 S.As''S 3 or KAsS 2 [or 3KS.2AsS 3 , ZKS.AsS 3 , 
 and KS.AsS 3 . Of these, the dibasic or tetrametallic salts are the most common, and 
 are regarded as neutral or normal sulpharsenites. 
 
 The soluble sulpharsenites are prepared : 1. By igniting sulpharsenates out of con- 
 tact with the air, 2 at. sulphur then escaping. 2. by dissolving arsenious sulphide in 
 an alkaline sulphide or sulphydrate; in the latter case, sulphuretted hydrogen is evolved. 
 3. By dissolving arsenious sulphide in a cold solution of caustic alkali. 4. By dis- 
 solving arsenious oxide in an alkaline sulphydrate, in which case half of the alkali is 
 converted into arsenite ; e.g.'. 
 
 As 2 3 + 2KHS = KAsS 2 + KAsO 2 + H 2 0. 
 
 The only sulpharsenites that are soluble in water are those of the alkali-metals, 
 alkaline earth-metals, and magnesium, and even these are decomposed by water, unless 
 the water is in considerable quantity. Hence the solutions cannot be evaporated to 
 dryness without decomposition. The solutions are colourless or yellowish, tasting 
 hepatic at first, and afterwards disgustingly bitter. 5. The sulpharsenites of the 
 earth-metals and heavy metals are obtained by precipitating a solution of the corre- 
 sponding compound of an alkali-metal, obtained by either of the methods 2, 3, 4, with 
 a salt of the earth-metal or heavy metal. (Berzelius.) 
 
 The sulpharsenites are either yellow or red. Most of them, when ignited out of 
 contact of air, give off all their sulphur-acid ; others give up such a quantity that the 
 residue contains 3 at. sulphur-base to 1 at. sulphur-acid ; but the sulpharsenites of the 
 alkali-metals, even those which contain equal numbers of atoms of base and acid, give 
 off nothing when ignited. The alkali-metal compounds obtained by the first method, 
 
SULPHARSENATES. 389 
 
 when treated with a small quantity of water, and the dilute s olutions obtained by 
 method 2, 3, or 4, when they evaporate in the air, are resolved into brown hyposulph- 
 arsenite which is precipitated, and sulpharsenate which remains in solution- but the 
 decomposition is not complete till the solution is concentrated to the crystallising 
 point of the latter salt. If the decomposed mass be digested in a large quantity of 
 water and boiled, the whole is reconverted into sulpharsenite and redissolved. The 
 solutions of the barium, strontium, calcium, and magnesium salts, containing 1 at. base 
 to 1 at. acid, deposit, on boiling, a portion of the arsenious sulphide ; the ammonium, 
 potassium, sodium, and litlmim compounds remain undecomposed. On adding alcohol 
 to the aqueous solution of a compound of 1 at. of arsenious sulphide with 2 at. of the 
 sulphide of an alkali-metal, a compound containing 3 at. of sulphur-base is precipi- 
 tated, while a compound containing 1 at. of sulphur-base remains in solution : 
 
 2(2K 2 S.AsS 3 ) = 3K 2 S.AsS 3 + K 2 S.AsS 2 . 
 
 But the precipitated tribasic salt soon turns black, being resolved into hyposulph- 
 arsenite and sulpharsenate. The potassium and sodium compounds exhibit this 
 blackening on the addition of alcohol, even when the solution contains nothing but 
 tribasic salt (3K 2 S.As'-'S 3 ) ; but with the ammonium, barium, strontium, and calcium 
 salts, it does not take place unless the solution contains dibasic salt (2Ba 2 S.As 2 S 3 ). 
 Aqueous solutions of sulpharsenites exposed to the air are decomposed by oxidation 
 (more slowly in proportion to the excess of sulphur-base), depositing orpiment and a 
 brown compound of disulphide of arsenic with the sulphur-base. Hydrated oxide of 
 copper, added to a solution containing a compound of sulpharsenious acid with the sul- 
 phide of an alkali-metal, decomposes that compound, yielding twelve-basic sulph- 
 arsenite of copper, which remains undissolved, and a hyacinth-red solution, containing 
 an alkaline arsenite and tribasic sulpharsenite of copper, and deposits the latter on the 
 addition of hydrochloric acid. Perhaps in this manner : 
 
 9(K 2 S.As 2 S 3 ) + 27Cu 2 = 2(12Cu 2 S.As 2 S 3 ) + 3Cu 2 S.As 2 S 3 + 3(3K 2 0.2As 2 3 ). 
 
 If the hydrated oxide of copper is in excess, the arsenious acid contained in the solu- 
 tion is converted into arsenic acid, and the protoxide of copper reduced to sub-oxide. 
 Oxide of silver in excess decomposes the solution, forming sulphide of silver and 
 alkaline arsenite : 
 
 KAsS 2 + 2Ag 2 = 2Ag 2 S + KAsO 2 . 
 
 Sulpharsenite of Ammonium, 2(NH 4 ) 2 S.As 8 S 3 . The solution of arsenious 
 sulphide in sulphide of ammonium or caustic ammonia yields, when mixed with 
 alcohol, a precipitate of this composition, which, however, soon turns brown. If 
 previously mixed with sulphydrate of ammonium, it deposits white feathery crystals of 
 the basic salt (3NH 4 ) 2 S.As 2 S 3 . Finely divided arsenious sulphide absorbs 6| per 
 cent, of ammonia-gas, but gives it up again when exposed to the air. 
 
 Sulpharsenite of Barium. The solution of arsenious sulphide in sulphydrate oi 
 barium dries up to a red-brown gummy mass of the neutral salt, 2Ba 2 S. As 2 S 3 , perfectly 
 soluble in water. Alcohol precipitates from the solution crystalline flakes of the basic 
 salt, 3Ba 2 S.As 2 S 3 , which is likewise obtained by treating arsenious sulphide with excess 
 of sulphide of barium. 
 
 Sulpharsenite of Bismuth, 2Bi 2 S 3 .As 2 S 3 , is a red-brown precipitate, which 
 turns black in drying. By fusion, a grey metallic-shining mass is obtained, con- 
 sisting of the basic salt. 
 
 Sulpharsenite of Cadmium. Cadmium-salts mixed with a saturated solution 
 of arsenious sulphide in sulphide of ammonium, yield a yellow precipitate, 2Cd 2 S.As 2 S 3 . 
 which becomes orange-yellow when dry, and semifluid when heated, giving off part of 
 the arsenious sulphide, and leaving a fused grey compound containing a larger pro- 
 portion of cadmic sulphide. 
 
 Sulpharsenite of Calcium. When orpiment is digested with milk of lime, and 
 the solution is filtered from the arsenite of calcium, which forms at the same time, a 
 colourless filtrate is obtained, which, by spontaneous evaporation, yields feathery 
 crystals of the basic salt 3Ca 2 S.As 2 S 8 , surrounded by a brown syrup of the neutral salt 
 2Ca 2 S.As 2 S 3 . This syrup digested with an additional quantity of arsenious sulphide 
 turns yellow and deposits a brown powder consisting of hyposvlpharsenite of calcium, 
 Ca 2 S.2AsS. The solution of the sulpharsenite containing excess of sulphide of calcium 
 yields, with alcohol, a white precipitate of the basic salt, containing 3Ca'-S.As 2 S 3 + 15Aq. 
 
 Sulpharsenite of Cerium, 2Ce 2 S.As 2 S 3 . Yellow precipitate, which acquires a 
 deeper colour when dry, melts, and evolves part of the arsenious sulphide when heated, 
 nd when roasted gives up all its arsenic, and is completely converted into sulphate. 
 
 Sulpharsenite of Chromium, 2Cr < S 3 .3As 2 S 3 . Greyish-yellow precipitate, 
 
 an 
 
390 ARSENIC: SULPHIDES. 
 
 greenish-yellow after drying. When heated, it melts and gives off part of the 
 arsenious sulphide, and is converted into chromic oxide by roasting. 
 
 Sulpharsenite of Cobalt, 2Co ? S.As 2 S 3 , is a dark brown precipitate, which 
 becomes black in drying, dissolves in excess of the precipitant, and when ignited 
 in close vessels, leaves a residue having the composition of cobalt-glance. 
 
 Sulpharsenite of Copper. A twelve-basic salt, 12Cu 2 S.As'-'S 3 , remains undis- 
 solved as a brown mass, when cupric hydrate is added to solution of monopotassic 
 sulpharsenate, till the colour of the liquid is no longer altered. The tribasic salt, 
 3Cu 2 S.As 2 S s , is precipitated in light brown flakes on adding hydrochloric acid to the 
 hyacinth-red solution obtained in the manner just mentioned. The neutral salt, 
 2Cu 2 S.As 2 S, is obtained by adding neutral sulpharsenite of sodium to a cupric salt, as 
 . a black-brown precipitate, which acquires a metal-grey aspect by trituration. When 
 distilled, it first gives off sulphur, then arsenious sulphide, and leaves a tumefied 
 metal-grey substance, probably consisting of cuprous hyposulpharsenite. 
 
 Sulpharsenite of Glucinum, 2G 2 S.As 2 S 3 , is a yellow precipitate, formed, without 
 evolution of sulphuretted hydrogen, on adding a neutral glucinum-salt to a solution 
 of sulphide of sodium saturated with arsenious sulphide. Acids separate but little 
 sulphuretted hydrogen from it, ammonia partly dissolves it, and leaves pure glucina. 
 
 Sulpharsenite of Gold, 2Au 2 S 3 .3As 2 S 3 . Yellow precipitate, becoming darker 
 as it settles down, black when dry, and yielding by trituration a yellow-brown powder. 
 At a dull red heat, it melts, gives off part of the arsenious sulphide, and solidifies to a 
 transparent yellow-red mass, yielding by dry trituration a yellow-brown mass, which, 
 however, by continued trituration under water, assumes a metallic lustre, as if 
 from reduced gold. To expel the whole of the arsenious sulphide requires a full 
 white heat. 
 
 Sulpharsenites of Iron. The ferric salt, 2Fe 4 S 3 .3As 2 S s , is an olive-green 
 precipitate, soluble in excess of the precipitating alkaline sulpharsenite, acquiring a 
 green colour when dry, and a fine yellow-green by trituration. It melts easily when 
 heated, and decomposes at a red heat, leaving pure sulphide of iron. Theferrous salt, 
 2Fe 2 S.As 2 S 3 , / is a brown-black precipitate, also soluble in excess of the precipitant; 
 grey-brown when dry, dark greenish after trituration. It is decomposed by heat, 
 leaving pure sulphide of iron. The dried precipitate always contains ferric oxide 
 mixed with the preceding salt. 
 
 Sulpharsenite of Lead, 2Pb 2 S.As 2 S 3 . Red-brown precipitate, black when dry; 
 melts to a brittle metallic-looking mass, a shining grey crystalline fracture, and yield- 
 ing a grey powder. 
 
 Sulpharsenite of Lithium resembles the potassium- and sodium-salts. 
 
 Sulpharsenite of Magnesium. The aqueous solution evaporated, or cooled 
 to 5 C., becomes light brown, and deposits a brown powder consisting of hyposul- 
 pharsenite of magnesium ; then dries to a viscid mass, which ultimately solidifies, 
 and is almost wholly soluble in water. 
 
 Sulpharsenite of Manganese. Light red precipitate, becoming orange-yellow 
 when dry. Heated in close vessels, it gives off a considerable portion of the arsenious 
 sulphide, and leaves a yellow-green compound, from which hydrochloric acid extracts 
 the manganese, with evolution of sulphuretted hydrogen, leaving a residue of arsenious 
 sulphide. 
 
 Sulpharsenites of Mercury. The neutral mercuric salt, 2Hg 2 S.As 8 S 3 , is an 
 orange-red flocculent precipitate, which becomes white in presence of excess of mercuric 
 chloride, but retains its colour if the precipitant is in excess. It is dark brown when 
 dry, and gives a yellow powder. When heated, it yields a grey metallic-shining sub- 
 limate of Hg 2 S.As 2 S 3 , which is translucent in thin films, and yields a yellow powder 
 when finely ground. The mercurous salt, 2Hg 4 S.As 2 S 3 , is a black precipitate, which 
 decrepitates with explosion when distilled, giving off mercury and yielding a sublimate 
 of mercurous hyposulpharsenite in black opaque metallic crusts, which yield a red 
 powder. 
 
 Sulpharsenite of Molybdenum. The solution of molybdic acid in hydrochloric 
 acid forms with sulpharsenite of sodium, a dark brown powder, which becomes black in 
 drying, and decomposes at a red heat, giving off arsenious sulphide and sulphur, and 
 leaving disulphide of molybdenum, MoS. 
 
 Sulpharsenite of Nickel, 2Ni 2 S.AsS 3 , is a black precipitate, which, when distilled, 
 easily gives off all its arsenious sulphide, and leaves yellow sintered sulphide of nickel. 
 
 Sulpharsenite of Potassium. The neutral salt, 2K 2 S.As 2 S 3 , is obtained by 
 igniting the corresponding sulpharsenate (2K 2 S.As 2 S 5 ) till the excess of sulphur is 
 
SULPHARSENATES. 391 
 
 driven off. It is a dark yellow mass, which becomes yellow on cooling. Treated with 
 water, it yields a solution of basic sulpharsenate (3K 2 S.As 2 S 5 ) and a residue of 
 hyposulphursenite. When arsenious sulphide is dissolved at mean temperature in 
 aqueous sulphydrate of potassium, till all the sulphuretted hydrogen is eliminated, 
 the solution contains an acid sulpharsenite, K 2 S.2As 2 S 3 . This solution is decomposed 
 by evaporation, depositing brown hyposulpharsenite of potassium, K 2 S. AsS. On mixing 
 the solution with alcohol, a white precipitate of 3K 2 S. As 2 S 3 is formed at first ; but 
 it soon becomes brown and syrupy, and deposits the hyposulpharsenite. When car- 
 bonate of potassium is fused with arsenious sulphide till the excess of the latter is 
 expelled, there remains a mass, consisting of K 2 S.As 2 S 3 . This salt is decomposed by 
 water, the acid salt, K 2 S.2As 2 S 3 , dissolving, and a compound, still richer in arsenious 
 sulphide, remaining undissolved. 
 
 Sulpharsenite of Silver, 2Ag 2 S.As 2 S 3 , is a light brown precipitate, transparent 
 at first, becoming black during collection ; when heated in the dry state, it melts and 
 gives off part of the arsenious sulphide. The black fused mass yields a brown powder. 
 When acid sulpharsenite of sodium is precipitated by a saturated solution of chloride 
 of silver in ammonia, a dark yellow precipitate is formed, containing 6Ag 2 S.As 2 S 3 . 
 
 Sulpharsenite of Sodium. Strictly analogous to the potassium-salt. 
 
 Sulpkarsenites of Tin. The stannous salt, 2SnS.As 2 S 3 , is a dark red-brown 
 precipitate, infusible, but giving off part of its sulphur at high temperatures. The 
 stannic salt, SnS 2 .As 2 S 3 , is a gummy yellow precipitate, which becomes orange-yellow 
 when dry. 
 
 Urania Sulpharsenite, 2TJ 4 S 3 .As 2 S 3 , is a dingy yellow precipitate, which melts 
 and gives off part of its sulphur when heated, and, after exposure to a white heat, 
 leaves a grey porous mass, still containing arsenious sulphide. 
 
 Sulpharsenite of Zinc, 2Zn 2 S.As 2 S 3 . Lemon-yellow precipitate, orange-yellow 
 when dry ; gives off arsenious sulphide when heated, leaving a more basic compound, 
 and at a higher temperature, pure sulphide of zinc. 
 
 Sulpharsenite of Zirconium, 2Zr 4 S 3 .As 2 S 3 . Orange-yellow precipitate, quite 
 insoluble in excess of the alkaline sulpharsenite. 
 
 PENTASULPHIDE OF ARSENIC, or ARSENIC SULPHIDE. In combination: 
 SULPHARSENIC ACID. As 2 S 5 , or AsS 5 . A substance containing arsenic and sulphur 
 in this proportion is precipitated when a soluble sulpharsenate is decomposed by hy- 
 drochloric acid ; but it appears to be rather a mixture of the trisulphide with free 
 sxilphur. When sulphuretted hydrogen is passed into an aqueous solution of arsenic 
 acid, sulphur is first separated, and remains for a long time suspended in the liquid. 
 The precipitate contains a very small quantity of trisulphide of arsenic, which may be 
 extracted by dilute ammonia, pure sulphur then remaining. The filtered liquid is then 
 found to contain arsenic acid, together with a small quantity of arsenious acid ; and, if 
 sulphuretted hydrogen be then rapidly passed through it for a short time, a precipitate 
 of trisulphide of arsenic is obtained. If this precipitate be separated by filtration, and 
 the passage of the sulphuretted hydrogen continued, the liquid again becomes turbid 
 from separation of sulphur, and, by repeating these operations, the whole of the 
 arsenic may be precipitated as trisulphide. (H. Rose, Pogg. Ann. cvii. 186; H. 
 Ludwig, Arch. Pharm. [2] xcvii. 23.) 
 
 A sulphide of arsenic corresponding to anhydrous arsenic acid, As 2 5 , does not 
 therefore appear to exist in the free state. Nevertheless, the precipitate thrown down 
 by acids from solutions of sulpharsenates has the composition of the pentasulphide, 
 and as such dissolves completely in alkaline sulphides and in strong ammonia ; dilute 
 ammonia, however, dissolves out the trisulphide and leaves the sulphur. 
 
 SULPHARSENATES. These salts may be regarded as compounds of pentasulphide of 
 arsenic with basic metallic sulphides. Our knowledge respecting them is chiefly due 
 to the researches of Berzelius. They are for the most part mono-, di, or tribasic, a few 
 instances only occurring of sulpharsenates with larger proportion either of sulphur- 
 base or sulphur-acid. Their general formulae are : 
 
 Monobasic or Monometallic . M 2 S.As 2 S 5 or MAsS 3 
 Dibasic or TetrametaUic . 2M 2 S.As 2 S 5 or M 4 As 2 S T 
 
 Tribasic or Trimetallic 3M 2 S.As 8 S 9 or M 3 AsS 4 = A 
 
 M.' 
 
 * Or MS.AsP, 2MS.AsS\ and 3MS.At&. 
 cc4 
 
392 ARSENIC: SULPHIDES. 
 
 The tetrametallic salts are generally regarded as neutral ; the monometallic as acid ; 
 the trimetallic as basic. 
 
 The sulpharsenates are prepared: 1. By passing sulphuretted hydrogen through the 
 solution of an arsenate in water or in hydrochloric acid, thus : 
 
 K 3 As0 4 + 4H 2 S = K 8 AsS 4 + 4H 2 0. 
 
 2. Byfusing orpiment with excess of sulphur and a caustic alkali or alkaline carbonate. 
 3. By digesting the trisulphide in an aqueous solution of a disulphide or polysulphide 
 of alkali-metal. 4. By dissolving the pentasulphide (As 2 S 3 + 2S) in a caustic alkali, 
 or in an alkaline carbonate at the boiling heat. In this case an arsenate is formed at 
 the same time. 6. Those sulpharsenates which are insoluble in water may be obtained 
 by precipitation from the solution of an alkaline sulpharsenate. 
 
 The dry sulpharsenates of the alkali -metals are lemon-yellow ; the others red or 
 brown. They are permanent in the air. Those which are soluble taste hepatic at 
 first, afterwards intensely bitter. The tribasic salts have a tendency to crystallise ; 
 the dibasic and monobasic salts are amorphous. 
 
 The trimetallic sulpharsenates of potassium, sodium, lithium, and barium may, if air 
 be excluded, be heated almost to whiteness without decomposition ; on cooling, they 
 solidify to a yellow mass perfectly soluble in water. The tetrametallic and monometallic 
 sulpharsenates of these metals give off sulphur when heated, and are converted into 
 sulpharsenites. The silver- and mercury-salts (the latter of which sublimes) remain 
 undecomposed at a red heat. The other tetrametallic and monometallic sulpharsenates 
 are decomposed by ignition, first yielding sulphur and a red salt of sulpharsenious acid ; 
 and in many cases, the sulpharsenite is resolved by continued ignition into trisulphide 
 of arsenic, which sublimes, and the sulphur-base, which remains behind. The calcium- 
 and magnesium-salts first evolve sulphur, and then the greater part of the trisulphide, 
 and leave a white unfused compound of magnesium- or calcium-sulphide, with a very 
 small quantity of trisulphide ; most of the heavy-metal-compounds evolve sulphur at 
 first, and then all the sulphide of arsenic, so that nothing but the sulphur-base re- 
 mains behind. The sulpharsenates, when heated in the air, give off orpiment and 
 arsenious oxide, and leave a sulphate when the base contains an alkali-metal, and pure 
 oxide if it contains a heavy metal. The aqueous solution of the sulpharsenate of an 
 alkali-metal is decomposed by exposure to the air the liquid becoming turbid, and 
 depositing sulphur, pentasulphide of arsenic (As 2 S 3 + S s ) and a brown salt of hypo- 
 sulpharsenious acid, while alkaline arsenite and hyposulphite are formed, and the latter, 
 by further oxidation, is converted into sulphate ; the cooler and more concentrated 
 the solution, the more slowly does the decomposition proceed. Acids, even carbonic 
 acid, decompose the alkaline sulpharsenates, separating hydrosulphuric acid gas of a 
 peculiar odour, and precipitating a mixture of arsenious sulphide and sulphur. 
 Hydrated cupric oxide, introduced into the solution of an alkaline sulpharsenate, 
 decomposes a portion of that compound, forming alkaline arsenate and sulphide of 
 copper, a small portion of which dissolves in the liquid. A similar reaction is 
 produced by other heavy metallic oxides which do not retain their oxygen with very 
 great force. (Berzelius.) 
 
 Many sulpharsenates are soluble in water, namely, those of the alkali-metals, 
 magnesium, yttrium, and glucinum. The solutions are either colourless or pale yellow. 
 From the solutions of the dibasic salts alcohol precipitates a tribasic salt, and leaves 
 monobasic salt, in solution. When this solution is placed in a shallow dish, and 
 evaporated at a gentle heat, there remains a lemon-yellow residue, from which water 
 extracts a dibasic salt. (Berzelius.) 
 
 Sulpharsenate of Ammonium. 2(NH 4 ) 2 S.As 2 S 5 = (NH 4 ) 4 As 2 S 7 . The solution 
 of pentasulphide of arsenic in sulphide of ammonium, yields by evaporation, a viscid, 
 reddish-yellow mass, which decomposes partially in drying, and still more when heated, 
 first giving off a liquid containing disulphide of ammonium, and then yielding a sub- 
 limate of arsenious sulphide : (NH 4 ) 4 As 2 S 7 = 4NH 4 S + As 2 S 3 . The solution becomes 
 brownish-yellow when boiled, and on cooling deposits a yellow powder composed of 
 (NH 4 ) 2 S.12As 2 S 5 . The aqueous solution of the dibasic salt is precipitated by alcohol, 
 the monammonic or acid salt, NH 4 AsS 3 , then remaining in solution. If the solution be 
 previously mixed with sulphide of ammonium and heated, alcohol throws dqwn the 
 tri-ammonic or basic salt (NH 4 ) 3 AsS 4 , in prismatic crystals. 
 
 Sulpharsenate of Antimony is a burnt-yellow, easily fusible precipitate. 
 
 Sulpharsenate of Barium. The tribarytic-salt, Ba 3 AsS 4 , is obtained by decomr 
 posing the tetrabarytic or neutral salt: 1, by a red heat ; 2, by mixing its aqueous solu- 
 tion with sulphide of barium, the mixture evaporated in vacuoover sulphuric acid at the 
 freezing point, yielding the basic salt in loose, transparent, non-crystalline scales ; 3, by 
 
ARSENIC: SULPHAR SENATES. 393 
 
 precipitation with alcohol : it then falls down as a curdy precipitate, very soluble in 
 water, probably a hydrate : The dibasic salt, Ba 4 As 2 S 7 = 2Ba 2 S.As 2 S 5 , is produced by 
 saturating a solution of neutral arsenate of barium with hydrosulphuric acid. The 
 solution dries up to a fissured lemon-yellow mass, which, if exposed to the air after all 
 its water has been drawn off, absorbs water again, swelling up and falling to pieces 
 at the same time. It dissolves in water in all proportions. With sulphate of potas- 
 sium, it yields a precipitate of sulphate of barium, and a solution of neutral sulph- 
 arsenate of potassium. The monobarytic or acid salt, BaAsS 3 , remains in solution 
 when the neutral salt is precipitated by alcohol. It is decomposed by evaporation, 
 yielding a yellow deposit of the salt, Ba 2 S.3As 2 S 5 , while the neutral salt remains in 
 solution. 
 
 Sulpharsenate of Bismuth. Both the basic and the neutral salts are dark- 
 brown precipitates, soluble in excess of the alkaline sulpharsenate. 
 
 Sulpharsenate of Cadmium is a light yellow powder. 
 
 Sulpharsenate of Calcium. The basic salt, Ca 3 AsS 4 , is obtained by mixing the 
 solution of the neutral salt with sulphide of calcium, and either evaporating or precipi- 
 tating with alcohol ; it is not crystallisable, and when precipitated by alcohol, forms 
 either a powder or a syrup, according to the quantity of water that it contains. It 
 dissolves easily in water, but is insoluble in alcohol. The neutral salt, Cu 4 As 2 S 7 = 
 2Ca 2 S.As 2 S 5 , is precisely analogous to the barium-salt. Its solution when evaporated, 
 coagulates to a syrup, which, if then left to evaporate further, dries up to a yellow 
 opaque mass, becoming anhydrous at 60 C. : when exposed to the air, it absorbs 
 water, swells up, and detaches itself from the sides of the vessel. There appears to be 
 no acid sulpharsenate of calcium. 
 
 Sulpharsenates of Cerium. The eerie salt, 2Ce 4 S 3 .As 2 S 5 , is a yellowish white 
 precipitate, not quite insoluble in water, and consequently not appearing in very 
 dilute solutions. The cerous salts, Ce 2 S.As' : S 5 , and 3Ce 2 S.As 2 S 5 , are obtained by 
 double decomposition as precipitates of a fine yellow colour, which become some- 
 what darker when dry. 
 
 Sulpharsenate of Cobalt, Co 4 As 2 S 7 = 2Co ? S.As s S 5 , is a brown precipitate which 
 becomes black when collected and dried, and dissolves with dark colour in excess ol 
 sulpharsenate of sodium. 
 
 Sulpharsenate of Copper, Cu 4 As 2 S 7 = 2Cu 2 S.As 2 S 5 , is obtained as a dark brown 
 precipitate, by treating solutions of copper-salts with neutral sulpharsenate of sodium, 
 or by passing sulphuretted hydrogen through an acid solution containing arsenic acid 
 and cupric oxide : if the arsenic acid is in excess, the brown sulphur-salt is first 
 precipitated, and then yellow sulphide of arsenic. From a precipitate of this kind, 
 sulphide of ammonium dissolves not only the sulphide of arsenic, but likewise by its 
 intervention, a large portion of the sulphide of copper. Very dilute ammonia likewise 
 extracts the sulphide of arsenic : stronger ammonia acquires a brown tint by taking 
 up some of the sulphide of copper. (Grin. v. 475.) 
 
 Sulpharsenate of Glucinum. Pentasulphide of arsenic digested with hydrate 
 of glucinum and water, is dissolved to a small amount and reprecipitated by acids. 
 Glucinum-salts are not precipitated by sulpharsenate of sodium. 
 
 Sulpharsenate of Gold. The tribasic salt, (Au)AsS 4 = (Au) 2 S 3 .As 2 S 5 , is formed 
 by precipitating a gold-solution with tribasic arsenate of sodium. It is a dark brown 
 precipitate, soluble in pure water. Ferrous sulphate decolorises the solution, and 
 
 throws a yellow-brown substance not yet examined. The dibasic salt, 2(Au) 2 S 3 .3As 2 S 5 , 
 obtained by precipitation with neutral sulpharsenate of sodium, dissolves in pure 
 water, with brown red colour. 
 
 Sulpharsenates of Iron. The ferric salt, 2Fe 4 S 3 .3As 2 S 5 = or /e 4 As 2 S 7 , is a 
 greyish-green precipitate, which dissolves with very dark colour in excess of the pre- 
 cipitant, is not altered by drying, but melts easily when heated, giving off sulphur, 
 and being converted into ferric sulpharsenite. The ferrous salt, 2Fe 2 S.As 2 S 5 = 
 Fe 4 As 2 S 7 , is a dark brown precipitate, which dissolves in excess of the alkaline 
 sulpharsenate. It decomposes in drying, assuming a rusty colour, and then consists 
 of a mixture of the preceding salt with ferric oxide. 
 
 Sulpharsenate of Lead. The salts Pb 3 AsS 4 , and Pb 4 As 2 S 7 , are obtained by 
 precipitation. The former is black-brown, the latter of a fine red colour ; both turn 
 black in drying. 
 
 Sulpharsenate of Lithium.^ basic salt, Li 3 AsS 4 , is precipitated by alcohol 
 from the solution of the neutral salt in shining, colourless crystalline scales, soluble in 
 hot water, and separating therefrom on cooling in six-sided prisms, and by spontaneous 
 
394 ARSENIC: SULP II All SEN AXES. 
 
 evaporation in four-sided tables with rhombic base. The neutral salt, Li'As'S 7 , is a 
 non-crystalline lemon- yellow mass, which absorbs moisture from the air, and is perfectly 
 soluble in water. The acid salt, LiAsS 3 , is known only in alcoholic solution, being 
 decomposed by evaporation. The hyper acid salt, with 12 at. As'-'S 5 , is prepared like 
 the corresponding potassium-salt. 
 
 Sulpharsenate of Magnesium. The tribasic salt, Mg'AsO 4 or 3Mg 2 S.As 2 S 5 , is 
 obtained by adding sulphydrate of magnesium to a solution of the neutral salt as long 
 as sulphuretted hydrogen continues to escape, and afterwards evaporating the solution, 
 or if it be not too dilute, cooling it quickly down. It forms colourless radiating 
 crystals, which become moist on exposure to the air. Alcohol decomposes them, 
 extracting the neutral salt and leaving a compound of 1 at. As 2 S 5 with more than 
 3 at. Mg 2 S, which is nearly insoluble in water. The same compound remains as a 
 white unfused mass, when the neutral salt is heated to redness in a retort. Potash 
 added to the aqueous solution of the tribasic salt precipitates magnesia, and forms a 
 solution of tribasic sulpharsenate of potassium. The neutral salt, 2Mg 2 S.As 2 S 5 , is a 
 non-crystalline, lemon-yellow mass, which does not absorb water from the air, dis- 
 solves in water to any amount, and is precipitated from the solution by alcohol. 
 
 Sulpharsenate of Magnesium and Ammonium, (NH 4 )Mg 2 AsS 4 (?) Precipitated on 
 adding alcohol to an aqueous solution of the mixed sulpharsenates of magnesium and 
 ammonium, in delicate white needles, which, when exposed to the air, give off sul- 
 phuretted hydrogen and turn yellow. It dissolves easily in water. 
 
 Sulpharsenate of Manganese. The neutral salt, 2Mn 2 S.As 2 S 5 , is obtained by 
 digesting recently precipitated sulphide of manganese with water, trisulphide of 
 arsenic and sulphur, partly dissolving in the water and partly remaining at the bottom 
 in the form of a lemon-yellow powder, which however dissolves in a larger quantity 
 of water. The solution when evaporated, yields sulphur, and afterwards deposits a 
 lemon-yellow mass, no longer completely soluble in water. The neutral salt is like- 
 wise obtained, but mixed with arsenate of manganese, when carbonate of manganese 
 is boiled with water and trisulphide of arsenic and sulphur. Manganous salts are 
 not precipitated by sulpharsenate of sodium. A sexbasic salt, 6Mn 2 S. As 2 S 5 , is produced 
 by digesting the yellow powder of the neutral salt in strong ammonia. It is a brick- 
 red powder, somewhat soluble in water, and, when ignited at one point, continues to 
 burn. 
 
 Sulpharsenates of Mercury. The mercuric salt, 2Hg 2 S.As 2 S 5 , is precipitated 
 from mercuric chloride both by basic and by neutral sulpharsenate of sodium, as a 
 dark yellow substance, which retains its colour after drying. It sublimes undecom- 
 posed, and yields a powder of the colour of cinnabar. The mcrcurous salt, 2Hg 4 S. As 2 S 5 , 
 or Hhg 4 As 2 S 7 , is precipitated black from solutions free from mercuric oxide ; if 
 the latter is present, the precipitate is brownish-yellow, and becomes darker in 
 drying. When distilled, it decrepitates violently and gives off mercury, and at a 
 higher temperature yields a sublimate of the mercuric salt just described. 
 
 Motybdic Acid is is not precipitated by sulpharsenate of sodium. 
 
 Sulpharsenate of Nickel. Nickel-salts, if not too dilute, immediately yield a 
 black precipitate, with neutral or basic sulpharsenate of sodium. Very dilute solutions 
 first assume a yellow-brown colour, then yield a precipitate. 
 
 Sulpharsenate of Platinum. The neutral and basic sodium-salts do not 
 precipitate platinum-solutions, but merely colour them dark-brown. Ferrous sulphate 
 added to the brown liquid, throws down a black-brown substance, while the solution 
 becomes colourless. 
 
 Sulpharsenate of Potassium. The tribasic salt, 3K 2 S.As 2 S 5 , or K 3 AsS 4 , is 
 deposited as an oily concentrated solution, on mixing the aqueous solution of the 
 neutral salt with alcohol. When dried at a gentle heat, it leaves a fibrous deliquescent 
 mass. 
 
 The neutral or dibasic salt, 2K 2 S.As ? S 5 , or K 4 As 2 S 7 , is produced by saturating an 
 aqueous solution of dipotassic arsenate with hydrosulphuric acid and evaporating in 
 vacuo. The residue is a viscid, yellowish, somewhat crystalline mass, which does not 
 dry up completely, but on exposure to the air first liquefies and then solidifies in a 
 crystalline mass of rhombic tablets. 
 
 The monobasic or acid salt, K 2 S.As 2 S 5 , or KAsS 3 , remains dissolved when the aqueous 
 solution of the neutral salt is precipitated with alcohol. The solution is decomposed 
 by evaporation, and deposits crystals of persulphide of arsenic (see p. 386). 
 2 Aqueous sulphide of potassium dissolves at ordinary temperatures, more than at. 
 but less than 1 at. of pentasulphide of arsenic. The solution, when evaporated in 
 the air, first becomes covered with a film of sulphur, then deposits a red crust, and by 
 this loss of sulphide of arsenic, is converted into the dibasic salt, which dries up first to 
 a stiff syrup and then to a lemon-yellow mass. 
 
ARSENIC: SULPHAR SENATES. 395 
 
 A hyper-add salt, K 2 S.12As 2 S 5 , is precipitated when the solution of the neutral salt 
 is decomposed by carbonic acid ; similarly on passing hydrosulphuric acid gas through 
 monopotassic arsenate. It is a yellow powder, containing 2 '9 sulphide of potassium 
 and 97'1 pentasulphide of arsenic. (Berzelius.) 
 
 Sulphoxarsenate of Potassium. (K 2 0.2H 2 0)As 2 S 3 2 = (K 2 H 4 )As 2 S 3 5 . Produced 
 when sulphuretted hydrogen is rapidly passed through a cold saturated solution of dipo- 
 tassic arsenate (p. 383). The liquid first turns yellow, then deposits a small quantity of 
 trisulphide of arsenic mixed with sulphur, and ultimately a colourless crystalline salt. 
 When a certain quantity of this salt has been formed, caustic potash is to be added to 
 the liquid, and the stream of sulphuretted hydrogen continued: by this means, an 
 additional quantity is obtained. The greater part of the sulphide of arsenic must 
 then be rinsed away with the mother-liquor, and the salt washed with very small 
 
 ratities of water, pressed, and dried in vacuo. It crystallises in small white 
 gated prisms, sometimes 1 or 2 centimetres long, slightly soluble in water. The 
 dry salt is permanent in the air, and gives up all its water at 170 C., without melting. 
 It fuses over the spirit-lamp, giving off, first arsenic sulphide and then metallic arsenic. 
 The aqueous solution decomposes rapidly at a boiling heat, giving off hydrosulphuric 
 acid and depositing sulphur. If hydrochloric acid be then added, a precipitate of sul- 
 phide of arsenic is obtained. From the salt itself, hydrochloric acid precipitates 
 nothing but sulphur, and the precipitation is complete; the filtrate then contains 
 arsenious acid. Lead-salts added to the solution give a white precipitate, which soon 
 turns black. The acid of this salt, H 6 As 2 S 3 5 (arsenic acid, having part of its oxygen 
 replaced by sulphur), cannot be obtained in the free state. If the lead-salt, 
 immediately after its formation, be collected on a filter and mixed with a quantity 
 of dilute sulphuric acid less than sufficient to decompose it completely, a strongly acid 
 liquid is obtained, which gives no precipitate with barium-salts ; but it quickly decom- 
 poses and deposits sulphide of arsenic. (Bouquet and Cloez, Ann. Ch. Phys. [3] 
 xrii. 44.) 
 
 Sulpharsenate of Silver. Both the neutral and basic salts are precipitated from 
 silver- solutions, with brown colour, turning black in drying ; the precipitates are very 
 slow in settling down. When they are heated in the air, the sulphide of arsenic burns 
 away, and sulphide of silver remains ; but if heated to redness in close vessels, they 
 fuse without giving off sulphur or sulphide of arsenic, and on cooling solidify in the 
 form of a grey, somewhat ductile cake, exhibiting metallic lustre. 
 
 Sulpharsenate of Sodium, a. Tribasic salt. 3Na 2 S.AsS 5 + 15H 2 = 2Na s AsS 4 -f- 
 15H 2 0. Obtained : 1. By precipitating a solution of the dibasic salt with alcohol. 
 2. By leaving a mixture of the dibasic salt b and sulphydrate of sodium to evaporate. 
 3. By digesting the alcoholic solution of pentasulphide of sodium with orpiment, 
 pouring the liquid off, washing the residue with alcohol, then dissolving out the tri- 
 basic salt with water, and leaving the solution to crystallise. 4. By dissolving penta- 
 sulphide of arsenic in aqueous soda-solution, and leaving the liquid to crystallise. 
 The crystals obtained by either of these methods are washed on a filter with alcohol, then 
 pressed and dried (Berzelius). 5. By boiling 1 pt. of sulphur, 1| pt. of orpiment, 
 and 8 pts. of crystallised carbonate of soda with water, and purifying the crystals ob- 
 tained from the filtrate by recrystallisation (Kammelsberg, Pogg .Ann. liv. 238). 
 By method (1) the salt is obtained in snow-white crystals; by (4) in ill-defined rhom- 
 boidal tables. It crystallises by slow cooling from a hot aqueous solution, in irregular 
 six-sided prisms, with two of their lateral edges more acute than the rest ; by spon- 
 taneous evaporation or very slow cooling, in transparent rhombic prisms with dihedral 
 summits resting on the acute lateral edges ; and by still slower cooling, till the tem- 
 perature falls below C., in white, opaque, rhombic octahedrons. The opaque 
 crystals are milk-white ; the transparent crystals are yellowish, and have somewhat 
 of a diamond lustre. (Berzelius.) 
 
 The salt when dry is permanent in the air ; even in vacuo over oil of vitriol, it 
 does not give up its water till gently heated ; it then becomes milk-white ; when more 
 strongly heated, it gives off a small quantity of hydrosulphuric acid, and turns yellow. 
 Heated in a retort, in fuses it its water of crystallisation, forming a very pale yellow 
 liquid, then gives off water, and is converted into a white salt, which, when more 
 strongly heated, decrepitates slightly, evolves the remaining water and a small quan- 
 tity of hydrosulphuric acid, and fuses to a dark red liquid ; on cooling, this liquid 
 solidifies and forms the yellow anhydrous compound, Na 3 AsS 4 (Berzelius). It is 
 decomposed completely by boiling with sulphate of copper, yielding a precipitate of 
 sulphide of copper, while soda, sulphuric acid, and arsenic acid remain in solution : 
 Na 3 AsS 4 + 4Cu 2 S0 4 + 4H 2 = 4Cu 2 S + Na 3 As0 4 + 4H 2 S0 4 . 
 
 A similar decomposition takes place with acetate of lead ; but the precipitated sul- 
 phide of lead [if the acetate is in excess], is mixed with arsenate of lead, because that 
 
396 ARSENIC-RADICLES (ORGANIC). 
 
 salt is insoluble in acetic acid (Rammelsberg). The salt dissolves easily and 
 abundantly in water. (Berzelius.) 
 
 b. Dibasic or Neutral salt. 2Na 2 S.As 2 S 5 =Na 4 As 2 S 7 . The aqueous solution of di- 
 sodic arsenate saturated with hydrosulphuric acid gas, and then left to evaporate spon- 
 taneously, yields a viscid liquid, and afterwards, if gently heated, a dry lemon-yellow 
 mass. This substance melts at a moderate heat, forming a very pale yellow liquid 
 (losing water at the same time if warmed in an open vessel), and on cooling solidifies 
 in a yellow mass, which softens when exposed to the air. (Berzelius.) 
 
 c. Monobasic salt. Na 2 S.As 2 S 5 = NaAsS 3 . When the tribasic salt is prepared with 
 alcohol according to method (1), the supernatant alcoholic solution contains the 
 mono-basic salt. On distilling off the alcohol, the liquid often deposits persulphide 
 of arsenic in beautiful crystals. 
 
 d. Hyper-acid salt, Na 2 S.12As 2 S 5 . Yellow powder, obtained like the potassium 
 compound. (Berzelius.) 
 
 Sulpharsenate of Sodium and Ammonium, (NH 4 ) 3 AsS 4 .]S"a 3 AsS 4 , is obtained by 
 mixing the solutions of the two basic salts with alcohol, and cooling slowly, where- 
 upon it collects on the sides of the vessel in small four-sided tables ; or more easily by 
 dissolving sal-ammoniac in an exactly proportional quantity of the basic sodium-salt 
 and leaving the solution to evaporate ; it then separates in yellowish six-sided prisms, 
 permanent in the air, and much more soluble in water than the sodium-salt. When 
 distilled, it gives off sulphide of ammonium with a little water, leaving sulpharsenite 
 of sodium. 
 
 The neutral sulpharsenates of sodium and ammonium dry up to a yellow mass when 
 mixed. 
 
 Sulpkarsenate of Sodium and Potassium. Very regular four-sided tables, having 
 a faint yellowish colour. 
 
 Sulpkarsenate of Strontium. The neutral salt is obtained in the same manner 
 as the barium-compound. On mixing the solution with alcohol, the basic salt is preci- 
 pitated, sometimes as a syrup, sometimes as a white powder, according as it is more or 
 less purified from the neutral salt. 
 
 Sulpharsenates of Tin. Both the neutral and basic sodium-salts form with 
 stannous chloride, a dark chestnut-brown precipitate ; with stannic chloride, pale 
 yellow gummy precipitates, becoming orange-yellow when dry. 
 
 Uranic Sulpharsenate. The neutral salt, 2U 4 S 3 .As 2 S 5 or (U 2 S) 4 As 2 S 7 , is a dingy 
 yellow precipitate ; the basic salt has a somewhat darker colour. Both dissolve with 
 dark brown colour in excess of the precipitant. 
 
 Van a die salts give no precipitate with sulpharsenate of sodium; but the blue 
 solution is decolorised. 
 
 Sulpharsenate of Yttrium. Resembles the glucinum-salt. 
 
 Sulpharsenate of Zinc. The neutral salt is a light yellow precipitate, the basic 
 salt till lighter; both are orange-yellow when dry. 
 
 Sulpharsenate of Zirconium. Solutions of zirconium-salts are precipitated, 
 though not immediately, both by basic and by neutral sulpharsenate of sodium ; the 
 precipitate is lemon-yellow while moist, orange-yellow after drying. Acids do not 
 extract zirconia from it. 
 
 ARSENICAL COBALT, COPPER, IRON, &c. See the several metals. 
 ARSENICAL PYRITES. See IRON, ARSENIDES OF. 
 
 ARSENICAL PYROPHORTTS. Arsenite of barium ignited with gum-traga- 
 canth, is said by Osann to yield a greyish-yellow pyrophoric mixture. 
 
 ARSENIC-RADICLES (ORGANIC). Arsenic unites with the alcohol- 
 radicles, forming compounds analogous to those of antimony, and containing 1 at. 
 arsenic, combined with 1, 2, 3, or 4 at. of the organic radicle. The following is a list 
 of the compounds of this class at present known. Those to which no formulae are 
 assigned, have been but imperfectly studied. 
 
 Arsenides of Allyl. 
 Arsenides of Amyl. 
 Arsenides of Ethyl: 
 
 Arsenethyl . As(C 2 H 5 ) 
 
 Arsendiethyl, or Ethyl-cacodyl . . . As(C 2 H 5 ) 2 
 
 Arsentriethyl, or Triethylarsine . . . As(C 2 H 5 ) 8 
 
 Arsenethylium, or Tetrothylarsonium . . As(C 2 H 5 ) 4 
 
ARSENIDES OF ETHYL. 397 
 
 bromethyl-triethylium 
 Arsenvinyl-triethylium 
 Ethylene-hexethyl-diarsonium 
 Ethylene-triethylarsammonium 
 Aurarsenethylium 
 
 As(C 2 H 4 Br)(C 2 H 5 ) 8 
 
 As(C 2 H 3 )(C 2 H 5 ) 3 
 
 As 2 (C 2 H 4 )"(C 2 H 5 ) 8 
 
 AsNH 3 (C 2 H 4 )"(C 2 H 5 ) s 
 
 As(C 2 H 5 ) 3 Au 
 
 Platarsenethylium As(C 2 H 5 ) 3 Pt 
 
 Arsenides of Methyl: 
 
 Arsenmethyl As(CH 3 ) 
 
 Arsendimethyl, or Cacodyl . As(CH 3 ) 2 
 
 Arsentrimethyl, or Trimethylarsine 
 
 Arsenmethylium, or Tetramethylarsonium 
 
 Arsentrimethyl-ethylium 
 
 Arsendimethyl-diethylium 
 
 Arsenmethyl-triethyliuin. 
 
 Arsendimethyl-diamylium 
 
 As(CH 3 ) 3 
 
 As(CH 3 ) 4 
 
 As(CH 3 ) 3 (C 2 H 5 ) 
 
 As(CH 3 ) 2 (C 2 H 5 ) 2 
 
 As(CH 3 )(C'H 5 ) 3 
 
 As(CH 3 ) 2 (C 5 H) 
 
 Arsenide of Tetryl (or Butyl). 
 Arsenide of Trityl (or Propyl). 
 
 These compounds are produced, like the antimonides of the alcohol-radicles, by dis- 
 tilling the iodides of these radicles with arsenide of potassium or sodium. Arsen- 
 dimethyl, or cacodyl, is likewise formed by distilling a mixture of arsenious oxide and 
 an alkaline acetate, and was obtained in this manner by Cadet, so long ago as 1760. 
 The di-trityl and di-tetryl compounds appear to be produced in a similar manner, by 
 distilling arsenious oxide with an alkaline valerate or butyrate. The compounds con- 
 taining 2 and 3 at. of alcohol-radicle, e. g. cacodyl and arsentriethyl, have been obtained 
 in the free state ; the rest only in combination. 
 
 The compounds containing 1 at. alcohol-radicle, such as As(CH 3 ), are di-atomic and 
 tetr-atomic, uniting with 2 and 4 at. Cl, I, &c. ; those with 2 at. alcohol-radicle, 
 cacodyl, for example, tire mono- and tri-atomic ; those with 3 at. alcohol-radicle, 
 As(C 2 H 5 ) 3 , for example, are di-atomic ; and .those which contain 4 at. alcohol-radicle, 
 e.g. As(C 2 H 5 ) 4 , are monatomic and triatomic. (See OKGANO-METAXZIC BODIES.) 
 
 Arsenides of Allyl. When iodide of allyl is heated with arsenide of potas- 
 sium, a number of liquid products are formed, having an extremely offensive odour, 
 and rising gradually in boiling point, so that their separation cannot well be effected, 
 and at the same time, a solid crystalline mass is formed, which appears to be the 
 iodide of arsenallylium or tetrallylarsonium, As(C 3 H 5 ) 4 I. (Cahours and 
 Hofmann, Phil. Trans. 1857, p. 335.) 
 
 Arsenides of Amyl. Iodide of amyl distilled with arsenide of potassium, 
 yields compounds analogous to the arsenides of ethyl and methyl. (Cahours and 
 Kiche.) 
 
 Arsenides of Ethyl.* 
 
 Three of these compounds, viz. arsendiethyl, As(C 2 H 5 ), arsentrictkyl, As(C 2 H s ) 3 , and 
 arsenethylium, As(C 2 H 5 ) 4 , are obtained by a process similar to that already described 
 for the preparation of stibtriethyl (p. 341), viz. by subjecting arsenide of sodium mixed 
 with quartz-sand, to the action of iodide of ethyl in an atmosphere of dry carbonic 
 acid gas. The action takes place without external heating, and when it is finished, the 
 resulting arsenides of ethyl may be separated one from the other either by fractional 
 distillation, or by treatment with ether. Arsenethyl, AsC 2 H 5 , is obtained by the 
 decomposition of arsendiethyl. 
 
 ARSENETHYL, or ARSENMONETHYL, As(C 2 H 5 ) = AsE. This radicle is not 
 known in the free state ; but the di-iodide is obtained (together with iodide of ethyl), 
 by the action of 2 at. iodine on 1 at. iodide of arsendiethyl, or of 3 at. iodine on 1 at. 
 arsendiethyl : 
 
 AsE 2 ! + P = El + AsEP 
 AsE 2 + P = El + AsEP. 
 
 The di-iodide distilled with 2 at. iodine, yields tri-iodide of arsenic (AsEP + P = 
 El + AsP). Treated with excess of oxide of silver and water, it is converted into 
 arsenmonethylic acid, As(C 2 H 5 )H 2 O s . (Cahours, Compt. rend. 1. 1022 ; Kep, 
 Chim. pure, ii. 256.) 
 
 ARSENDIETHYL, or ETHYL-CACODYL, As(C 2 H 5 ) 2 , is best obtained by treating 
 arsenide of sodium with excess of iodide of ethyl, in the manner just mentioned, 
 
 Landolt, Ann. Ch. Pharra. Ixxxix. 301 ; xcii. 365 ; Gm. ix. 70; Gerh. ii. 949 Cahours and 
 Riche, Cotnpt. rend, xxxvi. 1001 ; xxxix. 541 ; Jahresber. f. Chem. 1853, 487 ; 1854, 530. Cahours, 
 Compt. rend. xlix. 87 ; Jahresber. 1859, 430 ; further, Compt. rend. 1. 1022; R6p. Chim. pure, ii.255. 
 
398 ARSENIC-RADICLES (ORGANIC). 
 
 digesting the crude distillate with ether, mixing the ethereal extract with absolute 
 alcohol, expelling the ether by evaporation, and mixing the alcoholic solution with 
 water, which precipitates arsendiethyl, and retains in solution the iodide of arsenethy- 
 lium, formed by the union of arsentriethyl with the excess of iodide of ethyl. 
 
 Arsendiethyl is an oily liquid, having a faint yellowish colour, strong refracting 
 power, and a very disagreeable, pungent, alliaceous odour. It sinks in water without 
 mixing. Boils between 185 and 190 C. It absorbs oxygen rapidly from the air. 
 giving off vapours of arsenious oxide, and if it has been separated by fractional dis- 
 tillation, it takes fire when a drop of it is let fall on wood or paper ; but if it has been 
 precipitated by water from the alcoholic solution, it does not take fire till heated to 
 180 C. It is rapidly oxidised by strong nitric acid, with evolution of light and heat, 
 less completely by dilute nitric acid, which also forms with it a red substance analogous 
 to Bunsen's erythrarsin. Arsendiethyl reduces the noble metals, silver, mercury, &c. 
 from their solutions, and is at the same time converted into arsendiethylic add, 
 As(C 2 H 5 ) 2 H0 2 . 
 
 Arsendiethyl also unites directly with chlorine, bromine, iodine, and sulphur. These 
 compounds are liquids having a peculiarly repulsive and persistent odour, and attacking 
 the eyes strongly ; continued exposure to it produces headache and other unpleasant 
 symptoms. The iodide, As(C 2 H 5 ) 2 I, is prepared by saturating an ethereal solution of 
 arsendiethyl with an ethereal solution of iodine, and evaporating the ether. It is a 
 yellow oil, insoluble in water, but soluble in alcohol and ether. The alcoholic solution 
 mixed with nitrate or sulphate of silver, yields a precipitate of iodide of silver, and a 
 solution of nitrate or sulphate of arsendiethyl. 
 
 On gradually adding a dilute alcoholic solution of mercuric chloride to an alcoholic 
 solution of arsendiethyl, a white precipitate is formed, which however disappears 
 on boiling, and the solution yields on cooling a crystalline powder, consisting of 
 2Hg 2 O.As(C 2 H 5 ) 2 Cl s . This salt is inodorous,' sparingly soluble in cold water and in 
 alcohol, more soluble in boiling water : it is decomposed by strong nitric acid. Two 
 other crystalline compounds are formed at the same time, in small quantity. 
 
 Arsendiethylic Acid. As(CH 5 ) 2 H0 2 . When arsendiethyl is triturated with 
 red oxide of mercury under water, mercury separates out, and a solution of arsendi- 
 ethylate of mercury is formed : and by precipitating the mercuric oxide with baryta- 
 water, removing the excess of baryta by carbonic acid, decomposing the filtered solution 
 of arsendiethylate of barium with sulphuric acid, and evaporating, arsendiethylic acid 
 is obtained in crystals. This acid is also produced by the direct oxidation of arsen- 
 diethyl, as when that substance is left for some time in a loosely stoppered bottle ; also, 
 when its alcoholic solution is exposed to the air. or more quickly when that solution 
 is shaken up with oxygen gas. The crystals contain As(C 2 H 5 ) 2 H0 2 . They are 
 inodorous, have a slightly acid, afterwards bitter taste, deliquesce in the air, 
 and dissolve readily in water and alcohol, sparingly in ether. They melt at 
 190C., forming an oily liquid, which solidifies in a crystalline mass on cooling; but 
 at higher temperatures, they are decomposed, with evolution of arsenious oxide and 
 stinking arsenical products. The acid is not attacked by nitric acid, aqua-regia, or by 
 the milder reducing agents, such as sulphurous acid, and ferrous sulphate ; but phos- 
 phorous acid reduces it, forming a pungent oily liquid, probably the oxide of arsendi- 
 ethyl. The aqueous solution of the acid readily decomposes carbonates, and precipitates 
 ferric, mercurous, and cupric salts ; also acetate of lead. The mercuric salt is a deli- 
 quescent crystalline mass. The barium-s&lt, obtained by saturating the aqueous acid 
 with baryta-water and evaporating, contains 2BaH0.3As(C 2 H 5 ) 2 H0 2 + |H 2 0; the 
 water of crystallisation is not completely given off at 120 C. 
 
 ARSENTBIETHYL, or TRIETHYLARSINE. As(C 2 H 5 ) 3 . This is the chief product 
 of the action of iodide of ethyl on arsenide of sodium, and is easily separated from the 
 other products by fractional .distillation in an atmosphere of carbonic anhydride : it 
 passes over between 140 and 180C. It is also produced by the action of trichloride 
 of arsenic on zinc-ethyl (Hofmann and Cahours, Compt. rend. xli. 831). It is a 
 colourless, mobile, strongly refracting liquid, having a disagreeable odour, like that of 
 arsenetted hydrogen. Specific gravity 1-151 at 167 C. Under a pressure of 736 mm. 
 it begins to boil at 140 C., but the boiling point quickly rises to 180, a small quantity 
 of arsenic separating at the same time. Its vapour-density is, by experiment, 5'2783 ; 
 by calculation (2 vol.) 5-6156. 
 
 Arsentriethyl fumes and becomes heated in contact with the air, but seldom takes fire 
 unless it is heated : the products of the oxidation are arsenious anhydride, carbonic anhy- 
 dride and water. The oxidation takes place slowly, even under water in a closed vessel. 
 Strong nitric acid oxidises it rapidly, with vivid combustion and explosion, but nitric 
 acid of specific gravity 1-42, dissolves it slowly, giving off nitric oxide, and producing 
 nitrate of arsentriethyl ; but no red compound is formed. This character serves to 
 
ARSENIDES OF ETHYL. 399 
 
 distinguish arsentriethyl from arsendiethyl : a further distinction is afforded by tho 
 fact that arsentriethyl does not reduce the noble metals from their solutions. 
 
 Arsentriethyl is a diacid radicle, 1 at. of it uniting with 2 at. of a monatomic acid 
 radicle, e. g. As(C-H 5 ) 3 .! 2 , and with one at, of a diatomic acid radicle, e.g. As(C'-H 5 ) 3 .S. 
 
 Bromide of Arsentriethyl, As(C 2 H 5 ) 3 Br 2 , is obtained by mixing the alcoholic solu- 
 tions of bromine and arsentriethyl, the former in slight excess, and evaporating at 100 C. 
 It is a yellowish, deliquescent, crystalline mass, the odour of which excites sneezing. 
 When heated it melts, and burns with a white flame. It is decomposed by chlorine, 
 by nitric acid, and by strong sulphuric acid. 
 
 Iodide of Arsentriethyl, As(C 2 H 5 ) 3 I 2 , is obtained by mixing the ethereal solutions 
 of its constituents : it is then deposited in yellow flakes which rapidly turn brown and 
 liquefy on exposure to the air. It dissolves readily in water and alcohol, sparingly in 
 ether. 
 
 The chloride appears to be formed in small quantity by the action of hydrochloric 
 acid on the oxide or sulphide. 
 
 Oxide of Arsentriethyl, As(C 2 H 5 ) 3 0, is produced when an ethereal solution of 
 arsentriethyl is left to evaporate in the air; but it may be obtained in a state of greater 
 purity by exhausting the mass produced by the action of iodide of ethyl on arsenide of 
 sodium, first with ether, and then with alcohol, evaporating the alcoholic solution, and 
 distilling the residue. It is an oily liquid, heavier than water and not miscible with 
 it, but soluble in alcohol, and precipitated from the alcoholic solution by water. It 
 dissolves in dilute nitric acid, but not in sulphuric or hydrochloric acid. When left 
 for some weeks in a loosely stoppered bottle, it is gradually converted into an inodorous 
 crystalline substance [probably arsentriethylic acid]. 
 
 Sulphide of Arsentriethyl, As(C 2 H 5 ) 3 8, is obtained by boiling an ethereal solution 
 of arsentriethyl with flowers of sulphur. It forms beautiful prismatic crystals, which 
 may be purified by recrystallisation from boiling water or alcohol, or better by 
 solution in warm ether, and gradual evaporation. It has a bitter taste, but is quite 
 inodorous when pure. It melts at 100 C., and decomposes at a higher temperature, 
 giving off spontaneously inflammable vapours. It is rapidly oxidised by strong nitric 
 acid. Dilute hydrochloric acid decomposes it partially, giving off small quantities of 
 hydrosulphuric acid and. chloride of arsentriethyl, recognisable by its peculiarly pungent 
 odour. It is not decomposed by boiling with caustic potash. Its aqueous solution 
 precipitates metallic solutions like an alkaline sulphide. 
 
 ARSENETHYLIUM or TETKETHYLARSONIUM, As(C 2 H 5 ) 4 , is not known in the free 
 state, but is obtained as an iodide by the action of iodide of ethyl on arsentriethyl ; also, 
 according to Cahours and Kiche, by the action of metallic arsenic on iodide of ethyl. 
 Its compounds are analogous to those of tetrethylium, and contain 1 at. arsenethylmm 
 with 1 at. of a monobasic acid radicle, or 2 at. arsenethylium with 1 at. of a dibasic 
 acid radicle. The hydrate, obtained by the action of oxide of silver on the iodide, 
 is a fixed base resembling hydrate of potassium, and dissolves readily in acids, forming 
 salts which crystallise readily, are permanent in the air, have a bitter taste, and do 
 not appear to be poisonous. In this respect, they differ remarkably from the com- 
 pounds of arsendiethyl and arsentriethyl. 
 
 Bromide of Arsenethylium, As(C 2 H 5 ) 4 Br, is a white, deliquescent, saline mass, 
 which dissolves easily in water and alcohol, and exhibits with acids and metallic 
 salts, the same reactions as bromide of potassium. 
 
 Chloride of Arsenethylium forms crystals containing As(C 2 H 5 ) 4 C1.4H 8 0, 
 which dissolve readily in water and alcohol, but are insoluble in ether. The aqueous 
 solution immediately precipitates chloride of silver from the nitrate and forms an in- 
 soluble double salt with mercuric chloride. With dichloride of platinum it forms the 
 compound As(C 2 H 5 ) 4 Cl.PtCl 2 , which dissolves very sparingly in cold, somewhat more 
 readily in boiling water. 
 
 Iodide of Arsenethylium, As(C 2 H 5 )' l I, forms large colourless crystals, easily 
 soluble in water and alcohol, but insoluble in ether. When heated, they fall to 
 powder, give off spontaneously inflammable vapours, and yield a sublimate of arsenic. 
 They are decomposed by nitric and by sulphuric acid. A compound of iodide of arsen- 
 ethylium and iodide of arsenic is obtained by heating iodide of ethyl to 100 C. 
 with metallic arsenic : 
 
 4C 2 H 5 I + As 2 = As(C 2 H 5 ) 4 I.AsI 3 . 
 
 This compound forms splendid red tables, which are decomposed by distillation, yield- 
 ing iodide of arsentriethyl and iodide of arsendiethyl (Cahours and Kiche, Compt, 
 rend, xxxix. 546 )._ It is also^ decomposed by hot potash-solution, yielding iodide of 
 arsenethylium, iodide of potassium, and arsenite of potassium. Iodide of arsenethylium 
 
400 ARSENIC-RADICLES (ORGANIC). 
 
 heated with iodide of zinc, yields the compound As(C 2 H 5 ) 4 I.ZnI ; similarly with iodide 
 of cadmium. 
 
 Arsenethylium likewise forms a tri-iodide, As(C 2 H 5 ) 4 ! 3 , analogous to the tri-iodide 
 of tetrethylium discovered by "Weltzien. (Cahours, Compt. rend. 1. 1022 ; K6p. Chim. 
 pure, ii. 255.) 
 
 The sulphate, [As(C 2 H 5 ) 4 H]S0 4 , is formed by precipitating a solution of the iodide 
 with an acid solution of sulphate of silver. Granular crystals, easily soluble in water 
 and alcohol, sparingly in ether, and decomposed by heat, with evolution of acid vapours. 
 
 ARSEN-BROMETHYL-TRIETHYLIUM, or BROMETHYL-TRIETHYLARSONIUM. 
 As(C 2 H 4 Br)(C 2 H 5 ) 3 . The bromide of this radicle is obtained by heating a mixture of 
 triethylarsine with a very large excess of dibromide of ethylene, in sealed tubes at a 
 temperature not above 50 C., extracting the product with water, evaporating and recrys- 
 tallising from boiling alcohol. It forms beautiful crystals, extremely soluble in water, 
 the form of which exactly resembles that of the corresponding phosphonium-compound 
 (see PHOSPHORUS-RADICLES, ORGANIC). It contains the elements of 1 at. dibromide 
 of ethylene and 1 at. triethylarsine : 
 
 C 2 H 4 Br 2 + As(C 2 H 5 ) 3 = [As(C 2 H 4 Br)(C 2 H 5 ) 3 ]Br. 
 
 Nitrate of silver added in excess to the solution of the bromide, precipitates only half 
 the bromine ; the other half is precipitated on treating the nitrate with ammonia 
 (see AMMONIUM-BASES, p. 196). The platinum-salt of this radicle forms splendid 
 yellow needles, sparingly soluble even in boiling water. (A. W. Hofmann, Proc. Eoy. 
 Soc. xi. 62.) 
 
 ARSENVINYL-TRIETHYLIUM, or VINYL-TRIETHYLARSONIUM. As(C 2 H 3 ) 
 (C 2 H 5 ) 3 . The hydrated oxide of this radicle is obtained by treating bromide of bro- 
 methyl-triethylarsouium with excess of oxide of silver : 
 
 [As(C 2 H 4 Br)(C 2 H 5 ) 3 ]Br + Ag 2 = As(C 2 E 3 )(C-H 5 ) 3 
 
 A strongly alkaline solution is obtained which, when treated with hydrochloric acid 
 and precipitated by dichloride of platinum, yields beautiful, rather soluble octahedrons, 
 containing [As(C 2 H 3 )(C 2 H 5 ) 3 ]Cl.PtCl 2 - (Hofmann, loc. cit.) 
 
 ETHYLENE-HEXETHYLDIARSONIUM. As 2 (C 2 H 4 )"(C J H 5 ) 6 . Obtained as a dibro- 
 mide or dichloride, by digesting the bromide or chloride of bromethyl-triethylarsonium 
 with triethylarsine at 150 C. for two hours. The dibromide [As 2 (C 2 H 4 )"(C 2 H 5 ) c ]"Br 2 , 
 
 treated with oxide of silver, yields the hydrate [ As2 ( C2H T( C2 ^)Tjo2, which is a 
 
 powerful alkali, and forms with acids a series of beautiful salts : 
 
 The platinum-salt. [As(C 2 H 4 )"(C 2 H 5 ) 6 ]"Cl 2 .2PtCl 2 , is a pale yellow crystalline pre- 
 cipitate, soluble in water and in boiling hydrochloric acid, from which it crystallises 
 Dn cooling. 
 
 The gold-salt, [As 2 (C 2 H 4 )"(C 2 H 5 ) 6 CP.2AuCl 3 , crystallises from hydrochloric acid in 
 gold-coloured plates. (Hofmann, loc. tit.) 
 
 ETHYLENE -TRIETHYLARSAMMONIUM f(C 2 H 4 )"^ TPN! * The ^roweWe of 
 
 this radicle is obtained by heating the bromide of bromethyl-triethylarsonium with 
 ammonia to 100C. for two hours. Treated with oxide of silver, it yields the caustic 
 base [(0<HYXCH')HA S Nr , 
 
 crystallises from hydrochloric acid in needles, sparingly soluble in boiling water. The 
 gold-salt crystallises from hydrochloric acid in golden-yellow plates. (Hofmann, 
 loc. cit.) 
 
 The reactions by which the last four bases are obtained are precisely similar to 
 those which yield the corresponding compounds of the phosphorus series, and will be 
 more fully considered in the article PHOSPHORUS-RADICLES (ORGANIC), in which also 
 the phospharsoniums, containing both phosphorus and arsenic, will be described. 
 
 AURARSENETHYLIUM, As(C 2 H 5 ) 3 Au, and PL ATARSENETHYLIUM, As(C 2 H 5 ) 3 Pt. 
 
 The chlorides of these compounds are obtained in fine crystals by treating an alcoholic 
 solution of arsentriethyl with trichloride of gold and dichloride of platinum respec- 
 tively. (Hofmann, Ann. Ch. Pharm. cvii. 357.) 
 
 Arsenides of XVIethyl. 
 
 Cadet discovered, in 1760, that by distilling acetate of potassium with arsenious 
 oxide, a fetid brown-red liquid is obtained, which takes fire on exposure to the air. 
 But the nature of this liquid was not understood till Bun sen undertook its examination, 
 and showed that it contained a metalloidal radicle, AsC 2 H 8 , to which he gave the 
 the name Cacodyl (from KO.KOS, bad) on account of its extremely poisonous qualities. 
 
ARSENIDES OF METHYL. 4ui 
 
 Buns e u, moreover, isolated this radicle, and prepared a great number of its compounds, 
 showing that, in its chemical relations, it is precisely analogous to a simple metal. 
 This was the second instance of the isolation of a compound radicle, the separation of 
 cyanogen by Gray-Lussac having been the first. It has since been shown by Cahours and 
 Kiche(Compt. rend, xxxix. 341), that cacodyl or arsendimethyl, As(CH 3 ) 2 may 
 be obtained by the action of iodide of methyl on arsenide of sodium, other arsenides of 
 methyl, viz. As(CH 3 ) 8 and As(CH 3 ) 4 being formed at the same time. Lastly, Baeyer, 
 has obtained several compounds of arsenmonomethyl, AsCH 3 . 
 
 ARSENMETHYL, or ARSENMONOMETHYL, AsCH 3 = AsMe. (Baeyer, Ann. 
 Ch. Pharm. cvii. 279.) The dichloride of this radicle (which is not known in the sepa- 
 rate state) is produced either by the decomposition of trichloride of arsendimethyl 
 (cacodyl) by heat : 
 
 AsMe 2 Cl 3 = AsMeCl 2 + MeCl 
 
 Trichloride of Dichloride Chloride of 
 
 cacodyl. arsenmethyl. methyl. 
 
 or by the action of hydrochloric acid on cacodylic acid : 
 
 AsMe 2 2 H + 3HC1 = AsMeCl 2 + MeCl + 2H 2 0. 
 
 When a stream of dry hydrochloric acid gas is p.assed over cacodylic acid, basic per- 
 chloride of cacodyl (p. 408) is first formed ; but by the continued action of the gas, 
 this compound is also decomposed, with separation of water, which passes over in the 
 distillate, together with the dichloride. 
 
 Dichloride of arsenmethyl is a colourless, heavy, mobile liquid, having a strong 
 refracting power. It boils at 133 C., which is nearly the boiling point of tri- 
 chloride of arsenic. It does not fume in the air, and is not decomposed by water, but 
 dissolves rather freely in that liquid. It forms a white precipitate with sulphuretted 
 hydrogen. The vapour of this compound exerts a most violent action on the mucous 
 membranes : on smelling it, the eyes, nose, and the whole face swell up, and a peculiar 
 lancinating pain is felt, extending down to the throat. 
 
 Tetrachloride of Arsenmethyl, AsMeCl 4 . When chlorine is passed over a 
 mixture of dichloride of arsenmethyl and sulphide of carbon cooled to 10 C., large 
 crystals are obtained, which immediately decompose at temperatures near the freezing 
 point of water, yielding chloride of methyl and trichloride of arsenic : hence the 
 crystals consist of tetrachloride of arsenmethyl : 
 
 AsCH 3 Cl 4 = AsCl 3 + CH 3 C1. 
 
 Chlorobromide of Arsenmethyl, AsMeClBr, appears to be produced by the 
 spontaneous decomposition of chlorodibromide of cacodyl, bromide of methyl being 
 given off at the same time : 
 
 AsMe 2 ClBr 2 = AsMeClBr + MeBr; 
 
 but the liquid product of the decomposition is too unstable to admit of an examination 
 of its properties. 
 
 Iodide of Arsenmethyl, AsCH 3 ! 2 , is obtained by the action of hydriodic acid on 
 the alcoholic solution of the oxide (see below). The liquid yields by spontaneous 
 evaporation, shining yellow needles of the iodide an inch long. They are not altered 
 by contact with the air, but appear to decompose slowly by keeping (Baeyer). The 
 same compound is produced by the action of 2 at. iodine on iodide of cacodyl, or of 
 3 at. iodine on free cacodyl, iodide of methyl being set free at the same time. 
 (Cahours, Compt, rend. 1. 1022) : 
 
 AsMe 2 ! + I 2 = Mel + AsMe! 2 
 AsMe 2 + I 3 = Mel + AsMel 2 
 
 It melts at 25 C., and often remains liquid for a long time after cooling. It is colourless 
 and volatile without decomposition above 200 C. It is but slightly soluble in water, 
 but dissolves readily in alcohol, ether, and sulphide of carbon ; less readily, however, 
 in presence of free hydriodic acid. Hydrochloric acid converts it into chloride, and 
 hydrosulphuric acid into sulphide of arsenmethyl. (Baeyer.) Distilled with 2 at. 
 iodine, it yields iodide of methyl, and triiodide of arsenic, Asl 3 . (Cahours.) 
 
 Oxide of Arsenmethyl, As(CH 3 )0, is produced by the action of potash on the 
 dichloride : 
 
 AsMeCl 2 + 2KHO = AsMeO + 2KC1 + H 2 ; 
 
 but on distilling the product with excess of potash, complete decomposition takes place 
 and oxide of cacodyl is obtained, instead of oxide of arsenmethyl (see below). 
 VOL. I. D D 
 
402 ARSENIC-RADICLES (ORGANIC). 
 
 A better result is obtained by saturating the dichloride with carbonate of potassium, 
 then adding an excess of the latter, extracting with absolute alcohol, distilling off the 
 alcohol in a stream of carbonic acid, digesting the residue in sulphide of carbon, 
 which leaves chloride of potassium and other impurities undissolved, and leaving the 
 clear solution to evaporate. Oxide of arsenmethyl is then obtained in large cubical 
 crystals (not regular, however), which soon become dull, and assume the aspect of 
 white porcelain ; sometimes, however, crystals are obtained which retain tlreir trans- 
 parency, but they are then very imperfectly developed. The oxide is very heavy, 
 permanent in the air, and has a strong odour like that of asafoetida. It dissolves 
 slowly but abundantly in cold water, readily in hot water, also in alcohol, ether, and 
 sulphide of carbon. It melts at 95 C., and remains liquid for a considerable time 
 after cooling". It is decomposed by distillation, and the evolved vapours explode when 
 mixed with air. A portion volatilises, however, with the vapour of water or alcohol. 
 By distillation with hydrate of potassium, it is resolved into arsenious oxide and oxido 
 of cacodyl : 
 
 4As(CH 3 )0 = As 2 3 + As 2 (CH 3 )<0. 
 
 The oxide appears to possess rather basic than acid properties, as it does not unite 
 with baryta, but dissolves readily in acids ; its aqueous solution is neutral to vege- 
 table colours. Hydrochloric acid added to the concentrated aqueous solution throws 
 down the chloride of arsenmethyl in oily drops ; hydrobromic acid acts in like manner ; 
 hydriodic acid produces a yellow precipitate of the iodide ; and hydrosulphuric acid a 
 white precipitate of the sulphide. The oxide is not acted upon by hydrocyanic acid, 
 but is easily raised to a higher stage of oxidation by nitric acid, mercuric oxide, or 
 silver-oxide. Chlorine, bromine, and iodine added to its solution in sulphide of 
 carbon, form precipitates which soon decompose. Corrosive sublimate does not appear 
 to unite with it. 
 
 Arsenmethylic acid. As(CH 3 )H 2 3 . The barium-salt of this acid is obtained 
 by decomposing the dichloride of arsenmethyl with a slight excess of silver-oxide ; 
 filtering from chloride of silver ; treating the filtrate with excess of baryta-water ; re- 
 moving that excess by carbonic acid ; evaporating the filtered liquid to dryness over 
 the water-bath ; dissolving the residue in a small quantity of water ; and precipitating 
 by alcohol. The same salt may be obtained by decomposing the aqueous solution of 
 oxide of arsenmethyl with mercuric oxide (for which purpose the alcoholic distillate 
 obtained in the preparation of the oxide, vid. sup. may be used), decomposing the 
 resulting mercurous salt with baryta, and proceeding as before. 
 
 By carefully decomposing the barium-salt with sulphuric acid and evaporating the 
 filtrate over the water-bath, arsenmethylic acid is obtained in the form of a lami- 
 nated mass, resembling precipitated nitrate of urea. It is purified by solution 
 in hot alcohol, and crystallises, on cooling, in large spear-shaped laminae, composed of 
 small needles, united in arborescent groups, permanent in the air, and not containing 
 any water of crystallisation. It is a strong acid, having a pure, sour, agreeable, taste, 
 and capable of decomposing carbonates. It is very soluble in water, and dissolves in 
 alcohol more readily than cacodylic acid. All its salts either crystallise or form pre- 
 cipitates. It is a dibasic acid, the formula of its normal salts being As(CIP)0 3 M' 2 , 
 The barium-salt, prepared as above, crystallises in colourless needles, containing 10 at, 
 of water, which it gives up at 100 C. The anhydrous salt separates as a white powder, 
 composed of rhombic crystals, when the concentrated aqueous solution is evaporated 
 or mixed with alcohol. On examining with the microscope the precipitate produced 
 by alcohol, the rhombic crystals are seen to change in a few minutes into the long 
 needles of the hydrated salt. The salt is quite insoluble in alcohol, and may thus be 
 easily separated from cacodylate of barium, which is soluble in that liquid. Arsen- 
 methylate of silver, As(CH 3 )0 3 Ag 2 , is precipitated in small crystals, having a strong 
 nacreous lustre, on mixing the neutral solution of the barium-salt with nitrate of silver. 
 It is anhydrous, is but little altered by exposure to air and light, does not decompose 
 at 100 C., but explodes at higher temperatures, with rather strong detonation. 
 
 Sulphide of Arsenmethyl, As(CH 3 )S. Obtained bypassing sulphuretted hy- 
 drogen into water in which dichloride of arsenmethyl is immersed : 
 
 As(CH 3 )CP + H 2 S = As(CH 3 )S + 2HC1. 
 
 The chloride is then converted into a white mass of the sulphide, without the slightest 
 separation of sulphur. The product is dissolved in a mixture of alcohol and sulphide 
 of carbon, from which it crystallises by rapid evaporation in shining laminse, or by 
 slow evaporation in small prisms. It is insoluble in water, moderately soluble in 
 alcohol and ether, very soluble in sulphide of carbon. In the crystallised state, it 
 melts at about 100 C., but often remains fluid for a long time after cooling. It is 
 
ARSENIDES OF METHYL. 403 
 
 decomposed by heat, with separation of sulphide of arsenic. It is permanent in the 
 air, and has a faint odour like that of asafcetida. The alcoholic solution decomposes 
 the salts of silver, copper, lead, platinum, and mercurosum, with formation of me- 
 tallic sulphides, and produces a white cloud with mercuric chloride. 
 
 ARSENDIMETHYL or CACODYL. As(CH 3 ) 2 = Kd. (Cadet, Crell. N. Chem. Arch, 
 i. 212; Bunsen, Pogg. Ann. xl. 219; xlii. 145 ; Ann. Ch. Pharm. xxxvii. 6 ; xlii. 19 ; 
 Baeyer, Ann. Ch. Pharm. cyii. 257. Grm. ix. 316; Grerh. i. 626.) This body, together 
 with the products of its oxidation, constitutes the spontaneously inflammable liquid, 
 known as Cadets fuming liquid or alkarsin* To prepare this liquid, a mixture of equal 
 parts of acetate of potassium and arsenious oxide is distilled in a retort provided with a 
 receiver, from which a long tube passes into the chimney, to carry away the poisonous 
 gases evolved during the process. The retort is placed in a sand-bath and gradually 
 heated till it is red-hot at the bottom. A brown oleaginous liquid consisting of im- 
 pure cacodyl is then found in the receiver, together with metallic arsenic, and a 
 mixture of water, acetone, and acetic acid, which floats on the top. The reaction is 
 very complicated, considerable quantities of carbonic anhydride and hydride of methyl 
 (marsh-gas) being given off, together with other gases in smaller quantity ; but the 
 formation of cacodyl is evidently connected with the splitting up of acetic acid at a 
 red heat into carbonic anhydride and hydride of methyl (p. 12). The oily liquid, 
 which is very inflammable, is decanted by means of a syphon, the longer arm of 
 which dips under water. It is then washed with boiled water and distilled over 
 hydrate of potassium in a current of hydrogen. 
 
 Pure cacodyl is obtained by decomposing the chloride with metallic zinc, dissolving 
 out the chloride of zinc by water, and dehydrating the oily liquid, which sinks to 
 the bottom, by distillation from chloride of calcium. The strong tendency of ca- 
 codyl to take fire in the air and the extremely poisonous quality of its vapour, render 
 it necessary to perform all the distillations in sealed vessels, filled with dry carbonic 
 acid gas. Bunsen's method is as follows: 
 
 1. Chloride of cacodyl is prepared perfectly free from oxide, by distilling alkarsin 
 with strong hydrochloric acid, till the resulting chloride no longer emits the slightest 
 fume on exposure to the air ; or better, by mixing the dilute alcoholic solutions of 
 alkarsin and mercuric chloride, and distilling the resulting precipitate of cJiloromcrcurate 
 of cacodyl (Kd 2 0.4HgCl) with very strong hydrochloric acid. To free the distillate 
 obtained by either of these methods from water and hydrochloric acid, it is digested 
 for several days with a mixture of chloride of calcium and quick lime, contained in the 
 bulb-apparatus A (fiff* 74). The air is first expelled from this apparatus by a stream 
 of dry carbonic acid gas ; the lower extremity a is then dipped into the chloride of 
 cacodyl below the hydrochloric acid; the chloride of cacodyl is drawn into the bulb by 
 means of a hand-syringe attached by a caoutchouc tube to the upper end b ; and lastly 
 the apparatus is sealed at both ends and set aside for several days. 
 
 2. The decomposition of the chloride of cacodyl is effected in a second apparatus B, 
 represented in fig. 75. A moderately strong and rather wide gas-delivery tube is 
 blown out to a bulb in two places a, b, about six inches apart ; the lower extremity is 
 then drawn out and twice bent, as shown at c, d: the upper bulb a is partly 
 filled through the wide open end of the tube with small cuttings of pure zinc- 
 foil ; the upper end of the tube is then drawn out and bent, as shown in the figure, 
 and the whole apparatus is filled with perfectly dry carbonic acid gas. To introduce 
 the purified chloride of cacodyl into the bulb a, the tube of apparatus A is cut off 
 at c, just above the bulb ; the upper extremity / of the apparatus B, is then introduced 
 into bulb A ; and a quantity of the liquid, sufficient to half fill it, is drawn in by 
 moans of a hand-syringe connected with the lower end e, after which the lower end 
 of the tube is sealed by the blowpipe at c, and the upper end sealed and melted off at g, 
 close to the bulb a. The apparatus is now inverted, and the bulb a immersed in 
 water at 100 C. The reduction then takes place without evolution with gas, and 
 after some hours, the contents of the bulb a are converted into a white saline mass, 
 which appears to be a compound of cacodyl with chloride of zinc, and melts to an 
 oily liquid at 110 120 C. To separate the cacodyl from the chloride of zinc, the 
 
 * This liquid was supposed by Bunsen to be the oxide of cacodyl, (AsC 2 H 6 )2Q. It does not appear, 
 however, to be definite in constitution. Bunsen's analyses of it vary from 29'9 to 22-4 per cent- in the 
 carbon, and from 65-4 to 66'2 in the arsenic. Dumas (Ann. Ch. Phys. [3] viii. 362) found 22 and 23'2 
 percent, carbon, and from 68'9 to 69'3 per cent, arsenic. Now the formula of oxide of cacodyl requires 
 21-2 carbon, and 66 4 arsenic, while that of cacodyl itself requires 22'9 carbon, and 71 4 arsenic. These 
 results are quite in accordance with the supposition that Cadet's liquid is a variable mixture of cacodyl 
 and its oxide ; the spontaneous inflammability of the liquid likewise indicates the presence of free caco- 
 dyl. The true oxide of cacodyl (Bunsen's paracacodylic oxide, p. 407, supposed by him to be isoineric 
 with alkarsin), produced by slow oxidation of cacodyl or of alkarsin itself, is not spontaneously inflam- 
 mable. (Gerhardt.) 
 
 D D 2 
 
404 
 
 ARSENIC-RADICLES (ORGANIC). 
 
 end e of the apparatus is broken off under water which has been thoroughly froed 
 from air by boiling ; the whole apparatus is heated to expel the carbonic anhydride, and 
 then left to cool, till the bulb b is nearly filled with water ; the end e is again sealed ; 
 the apparatus inclined so that the water may flow into the bulb a ; and this bulb is 
 gently heated. The chloride of zinc then dissolves, and the cacodyl sinks to the 
 bottom as a heavy oily liquid. 
 
 Fig. 74. 
 
 . 75. 
 
 To dehydrate the cacodyl and purify it further, it is next transferred, with the same 
 precautions as before, into another apparatus A (fig. 74), the bulb of which contains 
 dry chloride of calcium : for this purpose, the bulb a of apparatus B is cut off at h, and 
 the apparatus A having been filled with dry carbonic acid gas, its lower extremity a is 
 introduced into the bulb a, and made to dip into the cacodyl below the watery liquid ; 
 the cacodyl is then drawn by suction with the syringe into the bulb of apparatus A, 
 which is then sealed at both ends, and set aside for some time. The dehydrated 
 cacodyl is next transferred into a second apparatus B, filled with dry carbonic acid 
 gas, and having some zinc-cuttings in the bulb a, and the two arms of the tubes are 
 then sealed and melted off just below the bulbs a, b. The bulb b is then immersed in 
 cold water; the cacodyl distilled into it by gently heating the bulb a with a spirit- 
 lamp, and then poured back ; and the rectification is repeated in this manner two or three 
 times. Lastly, the bulb b is cooled in a freezing mixture to 6 C., and left there till 
 about | of the liquid has crystallised, and the still liquid portion is poured back : that 
 which 'then remains in the solid state is pure cacodyl. 
 
 Cacodyl may also be prepared by heating the sulphide with mercury. 
 
 Propertits. Cacodyl is at ordinary temperatures a transparent colourless, strongly re- 
 fracting liquid, heavier than water. It boils near 170 C. Its vapour-density (referred 
 to air as unity) is by experiment 7'101, which shows that the formula of cacodyl in 
 the free state is As 2 C 4 H 12 = As 2 Me 4 = KdKd. For the atomic weight represented 
 by this formula is 210 ( = 2 . 75 + 4 . 12 + 12 . 1), and if this represents 2 vols. of 
 vapour, the weight of one vol. of vapour, that is to say, the specific gravity referred to 
 hydrogen as unity, is 105 ; and multiplying this by 0*0693, the specific gravity of 
 hydrogen referred to air, we obtain for the specific gravity of cacodyl-vapour referred 
 to air as unity, the number 7 '27 55, which is very near the number determined by 
 experiment. Cacodyl has a disgusting odour, somewhat like that of arsenetted hydro- 
 gen, and its vapour is very poisonous. It solidifies at 6 C. in square-based prisms. It 
 is sparingly soluble in water, very soluble in alcohol and in ether. When heated in a 
 close vessel to about 400 C. it is resolved, without deposition of carbon, into metallic 
 arsenic, and a mixture of 2 vol. marsh gas and 1 vol. olefiant gas : 
 
 As 2 C 4 H 12 = 2CH 4 + C 2 H 4 + As 2 . 
 
 Cacodyl takes fire in the air, at ordinary temperatures, even more readily than crude 
 alkarsin, yielding carbonic anhydride, water, and arsenious oxide, but if the quantity 
 of air present is not sufficient for complete combustion, a red compound, Bunsen's 
 erythrarsin, is formed at the same time. This red substance is also produced when 
 cacodyl is passed through red-hot tubes ; also by the action of protochloride of tin, 
 or phosphorous acid on cacodyl. It appears to contain C'H ?2 As c O 3 . Cacodyl exposed 
 
ARSENIDES OF METHYL. 405 
 
 to the gradual action of oxygen, as when air is passed into it in successive bubbles, is 
 converted first into oxide of cacodyl, and afterwards into cacodylic acid. It takes fire 
 in chlorine gas, and is converted by chlorine-water into chloride of cacodyl. It dis- 
 solves sulphur, forming a protosulphide or trisulphide of cacodyl, according to the 
 quantity. Fuming sulphuric acid dissolves it without blackening : the solution gives 
 off, even in the cold, a considerable quantity of sulplnirous acid, and yields by distil- 
 lation a product having an agreeable ethereal odour. It dissolves in nitric acid, 
 and the solution yields with nitrate of silver a crystalline precipitate of nitrate of 
 silver and cacodyl. 
 
 Bromide of Cacodyl, As(CH 3 ) 2 Br = KdBr, is obtained by distilling the chlo- 
 romercurate, As 2 C 4 H I2 0.4HgCl, with concentrated hydrobromic acid, and is pxirified 
 like the chloride. It is a yellow liquid, which does not fume in the air, and closely 
 resembles the chloride. When heated over mercury to a temperature between 200 
 and 300 C. it is decomposed, yielding free cacodyl and mercurous bromide. Heated 
 with water it forms an oxybromide. 
 
 Chloride of Cacodyl, As(CH 3 ) 2 Cl=:KdCl. Prepared by distilling the chloro- 
 mercurate with very strong hydrochloric acid, and purified from water and adhering 
 hydrochloric acid by placing it in contact with chloride of calcium and quick lime, and 
 distilling it in the hermetically sealed apparatus (fiff. 74) filled with dry car- 
 bonic anhydride. It is also produced by the action of chlorine-water on cacodyl. It 
 is a very mobile liquid, heavier than water, which does not solidify even at 45 C. 
 It boils a little above 100 C., forming a colourless vapour of specific gravity 4-56 
 (by calculation 4'85). It does not fume in the air, but emits a very pungent intoxi- 
 cating odour. The vapour mixed with air produces, when inhaled in rather large 
 quantity, swelling of the mucous membrane of the nose and extravasation of blood 
 in the eyes. The vapour evolved from the boiling liquid takes fire spontaneously 
 in the air, and explodes violently when heated with oxygen gas. 
 
 Chloride of cacodyl is insoluble in water and ether, but soluble in all proportions in 
 alcohol. Sulphuric and phosphoric acids decompose it, eliminating hydrochloric acid. 
 Strong nitric acid sets it on fire. It burns in chlorine gas, with copious deposition of 
 charcoal. Zinc, tin, and iron decompose it, setting the cacodyl free. With alcoholic 
 potash it yields chloride of potassium, and an ethereal liquid having a disagreeable 
 odour, and miscible in all proportions with water and alcohol. Mixed with solution of 
 nitrate of silver, it gives up the whole of its chlorine, forming a precipitate of chloride 
 of silver. 
 
 A subchloride or oxychloride of cacodyl, KdCl.#Kd 2 0, is obtained by the action of 
 water on the chloride, also by distilling alkarsin with dilute hydrochloric acid, rectify- 
 ing the product over a mixture of chalk and water, and redistilling in an atmosphere 
 of carbonic anhydride. It is a liquid which resembles the chloride, has a very offensive 
 odour, and boils at 109 C., giving off a vapour of specific gravity 5 -46. 
 
 Chlorocuprite of Cacodyl, KdCl.Cu 2 Cl, is obtained as a bulky white precipitate, on 
 mixing an alcoholic solution of chloride of cacodyl with a solution of cuprous chloride 
 in hydrochloric acid. In contact with the air, it turns green, and gives off very fetid 
 arsenical vapours. It is decomposed by heat into its component chlorides. 
 
 Chloroplatinate of Cacodyl. An alcoholic solution of chloride of cacodyl mixed with 
 dichloride of platinum, yields a red-brown precipitate, probably consisting of AsC 2 H 6 Cl. 
 
 PtCl 2 ; but on boiling this product with water, a yellow solution is obtained, which on 
 cooling, deposits crystals of a new compound, viz. : 
 
 Chloride of Cacoplatyl, AsC 2 H 4 PtCl.H 2 0, or rather AsC 2 H 4 pt 2 Cl.H-0, that is to 
 say, the chloride of a radicle, cacoplatyl, formed from cacodyl by the substitution 
 of 2 at. platinicum (pt. = 49 -9) for 2 at. hydrogen. It appears to be formed from 
 chloroplatinate of cacodyl, by abstraction of 2HC1. This salt forms needle-shaped 
 crystals, which are inodorous, have a nauseous taste, and are soluble in hot water and 
 alcohol. Ammonia dissolves it in all proportions, and the solution when evaporated 
 yields indistinct crystals insoluble in alcohol. Chloride of cacoplatyl sustains a tem- 
 perature of 164 C. without decomposing, merely giving off 4 per cent, of water, 
 which it takes up again when boiled with water. At higher temperatures, it turns 
 brown, and then burns away, giving off arsenical vapours and leaving arsenide of 
 platinum. Chloride of cacoplatyl is not attacked by hydrochloric acid ; sulphuric 
 acid colours it yellow. With iodide and bromide of potassium, it forms yellow, 
 precipitates of iodide and bromide of cacoplatyl, precisely similar in composition to 
 the chloride. With nitrate of silver, it forms a precipitate of chloride of silver, the 
 
406 ARSENIC-RADICLES (ORGANIC). 
 
 Trichloride of Cacodyl, As(CH 3 ) 2 Cl 3 . Produced: 1. By the action of perchloride of 
 phosphorus on cacodylic acid : 
 
 KdO^H + 2PCP = KdCP + 2PCPO + IIC1. 
 
 The chloride of phosphorus must be immersed in anhydrous ether, the cacodylic acid 
 in powder added by small portions at a time, and the action moderated by external 
 cooling. 2. By the action of chlorine on the monochloride. The latter compound, 
 when brought direct!}' in contact with chlorine gas, takes fire and undergoes complete 
 decomposition ; but if chlorine be led on to the surface of a solution of the mono- 
 chloride in sulphide of carbon externally cooled, the trichloride is formed in crystalline 
 laminae, which may be purified by washing with sulphide of carbon. 
 
 The trichloride, prepared by the first method, forms beautiful large prismatic crys- 
 tals, which, however, are very unstable, being instantly decomposed, at temperatures 
 between 40 and 50 C., into chloride of methyl and dichloride of arsen-monomethyl : 
 
 As(CH 3 ) 2 .CP = As(CH 3 )CP + CH 3 C1. 
 
 The decomposition takes place spontaneously in the course of a day at ordinary tem- 
 peratures, even when the compound is enclosed in sealed tubes. The crystals obtained 
 by the second method are much more stable. 
 
 Trichloride of cacodyl dissolves without decomposition in anhydrous ether, and sepa- 
 rates by quick cooling of a warm saturated solution, in laminae, by slow cooling, or 
 spontaneous evaporation, in transparent colourless prisms, which, however, become dull 
 even in a vacuum. It dissolves less freely in sulphide of carbon, from which it sepa- 
 rates in large laminae. Anhydrous alcohol decomposes it, forming a syrup, which, by 
 slow evaporation, yields crystals of basic perchloride of cacodyl, or hydrochlorate of 
 cacodylic acid : 
 
 As(CH 3 ) 2 Cl 3 + 2(C 2 H 5 .H.O) = As(CH 3 ) 2 2 H 2 Cl + 2C*H 5 C1. 
 
 Basic perchloride of Chloride 
 cacodyl. of ethyl. 
 
 The alcoholic solution, left to evaporate, gives off a substance, probably dichloride of 
 arsen-monomethyl (p. 401), which acts intensely on the mucous membranes. The tri- 
 chloride fumes in moist air, giving off hydrochloric acid, and forming basic perchloride 
 of cacodyl. The same decomposition takes place in the ethereal solution when ex- 
 posed to the air, the basic perchloride separating in long needles, the formation of 
 which may be accelerated by the addition of water or alcohol. The trichloride dis- 
 solves in water, with considerable rise of temperature, forming a solution of cacodylic 
 acid and hydrochloric acid : 
 
 As(CH s ) 2 Cl 3 + 2H 2 = As(CH 3 ) 2 2 H + 3HCL 
 
 The decomposition is exactly similar to the preceding, the basic perchloride containing 
 indeed the elements of cacodylic and hydrochloric acid : 
 
 As(CH 3 ) 2 2 H 2 Cl = As(CH 3 ) 2 2 H + HC1. 
 
 The ethereal solution of the trichloride does not attack mercuric oxide ; but on adding 
 alcohol, a brisk action takes place, and an oil separates which contains chlorine and 
 mercury, is soluble in alcohol, and precipitated by ether. On further addition of 
 mercuric oxide, the whole solidifies to a mass of corrosive sublimate, and the compound 
 of that substance with cacodylic acid (p. 408). Oxide of silver is also without action 
 on the ethereal solution. (B a e y e r. ) 
 
 Dibromochloride of Cacodyl, As(CH 3 ) 2 ClBr 2 . Bromine acts upon monochloride of 
 cacodyl in the same manner as chlorine. On adding bromine to a mixture of the 
 monochloride and sulphide of carbon, the dibromochloride is precipitated in the form 
 of a yellow crystalline body, which is even more unstable than the trichloride, being 
 quickly resolved into gaseous bromide of methyl, and a liquid which appears to be 
 chlorobromide of arsen-monomethyl, As(CH 3 ) 2 .ClBr, but is very unstable. (B a ey e r). 
 
 Cyanide of Cacodyl, As(CH 3 ) 2 .CN = KdCy, is obtained by distilling alkarsin 
 (Cadet's liquor) with strong hydrocyanic acid, or better with a concentrated solu- 
 tion of cyanide of mercury ; metallic mercury then separates, and cyanide of cacodyl 
 collects under the water in the receiver, in the form of a yellowish oil, which soon 
 solidifies in fine prismatic crystals. The liquid is decanted, and the crystals are dried 
 by pressure between bibulous paper. The crystals are oblique prisms, truncated on the 
 acute edges, and terminated by dihedral summits. It melts at 33 C., forming a colour- 
 less ethereal, strongly refracting liquid, which solidifies again on cooling. It boils at 
 140 C., yielding a vapour of specific gravity 4-63. It dissolves sparingly in water, much 
 more readily in alcohol and ether. It is intensely poisonous, more so than any Other 
 cacodyl-compound. A few grains of it diffused in vapour through the air of a room, 
 
ARSENIDES OF METHYL. 407 
 
 are sufficient to excite giddiness, delirium, numbness of the hands and feet, and even 
 loss of consciousness; these attacks, however, are of short duration, provided the 
 person affected make his escape in time. Cyanide of cacodyl is not decomposed by 
 dilute alkalis, but concentrated acids decompose it, with evolution of hydrocyanic 
 acid. With silver-solutions it forms a precipitate of cyanide of silver. It reduces 
 mercurous nitrate, but does not act on mercuric nitrate. With mercuric chloride, it 
 forms a white precipitate of chloromercurate of cacodyl. 
 
 Fluoride of Cacodyl, As(CH 3 ) 2 F = KdF. Produced by distilling the chloro- 
 mercurate with hydrofluoric acid. It is a colourless liquid, which has an offensive 
 odour, and attacks glass. 
 
 Iodide of Cacodyl, As(CH 3 ) 2 I = Kdl. When alkarsin is distilled with concen- 
 trated hydriodic acid, an oily liquid passes over, which on cooling deposits transparent 
 rhomboidal tables, consisting of oxyiodide ofeacodyl. To complete the separation, the 
 liquid is immersed in a freezing mixture, then decanted from the crystals, and afterwards 
 dried and rectified in the manner described for the chloride, the distillation being, how- 
 ever, discontinued when two-thirds of the liquid have passed over. Iodide of cacodyl thus 
 prepared is a yellowish, slightly syrupy liquid, having a strong repulsive odour. It is 
 heavier than melted chloride of calcium. It remains liquid at 10 C., and boils at a 
 temperature above 100 C. ; nevertheless it distils with the vapour of water. It does 
 not fume when exposed to the air, but gradually oxidises and deposits fine prismatic 
 crystals of cacodylic acid. It is soluble in alcohol and ether, but insoluble in water. 
 Nitric and sulphuric acids decompose it, setting iodine free. When heated in the air 
 it burns with a dazzling flame, giving off vapours of iodine. 
 
 Oxide of Cacodyl, As 2 C 4 H 12 = Kd 2 0. (Bunsen's Paracacodylic Oxide, see p. 
 403.) This compound is formed by the slow oxidation ofeacodyl ; also by the action of 
 reducing agents, such as hydriodic, hydrobromic, sulphydric, or phosphorous acid, 
 protochloride of tin, &c., on cacodylic acid. When air is made to bubble slowly through 
 alkarsin, that liquid is gradually converted into a syrup filled with crystals of caco- 
 dylic acid; and on dissolving in water the mass thus obtained, and distilling, water 
 having the odour of cacodyl passes over at first, and afterwards between 120 and 
 130 C., an oily liquid, which when dried over caustic baryta, and rectified out of con- 
 tact of air, yields pure oxide of cacodyl, in the form of a limpid oil, having a pungent 
 odour, sparingly soluble in water, and boiling at 120 C. When exposed to the air, it 
 oxidises very slowly, without fuming or rise of temperature, and is converted into 
 cacodylic acid. Air mixed with its vapour between 50 and 70 C. detonates violently 
 on the approach of a burning body. Oxide of cacodyl dissolves in hydrochloric, hy- 
 driodic, and hydrobromic acids, forming the chloride, bromide, and iodide of cacodyl. 
 
 Oxide of cacodyl forms with mercuric chloride, a white precipitate, which is a com- 
 pound of the two substances Kd 2 0.4HgCl. This compound, called chloromercurate 
 of cacodyl, is also produced by mixing a dilute alcoholic solution of alkarsin with 
 a dilute solution of mercuric chloride, the latter not being in excess. After several 
 crystallisations from boiling water, it forms silky tufts, and by slow cooling of the 
 solution, may be obtained in small rhombic tables; 100 pts. of boiling water dissolve 
 3-47 pts. of the compound : it is also soluble in alcohol, especially at the boiling heat 
 It is inodorous, but has a disagreeable metallic taste, and is very poisonous. When 
 heated in contact with the air, it decomposes without leaving any residue. With 
 hydrochloric, hydriodic, and hydrobromic acids, it forms chloride, iodide, and bromide 
 of cacodyl. 
 
 Oxide of cacodyl forms with mercuric bromide, a compound similar in composition 
 and properties to that just described, viz. the bromomercurate of cacodyl, 
 Kd'0.4HgBr. With nitrate of silver, it forms the compound 3Kd 2 0.2N0 3 Ag, which 
 separates in the form of a heavy, white, crystalline powder, on pouring a solution of 
 nitrate of silver into a cold solution of alkarsin in dilute nitric acid. This compound 
 sustains a temperature of 90 C. without decomposing, but explodes at 100 C., giving 
 off fetid arsenical products. With dichloride of platinum, oxide of cacodyl forms a 
 red-brown precipitate, and with cyanide of mercury a brown pulverulent precipitate, 
 resembling paracyanogen and smelling like dried nightshade berries. 
 
 Dioxide of Cacodyl, AsC 2 H 6 = KdO, or Cacodylate of Cacodyl, ^ | O 2 This 
 
 is the thick syrupy liquid which is produced by the slow oxidation of cacodyl or alkar- 
 sin, and gradually becomes filled with crystals of cacodylic acid. It is decomposed by 
 water, and the_liquid then yields a distillate of oxide of cacodyl, and leaves a residue 
 of cacodylic acid : 
 
 4KdO + H 2 = Kd 2 + 2Kd0 2 H. 
 
 Cacodylic Acid, AsC 8 H 7 2 = Kd0 2 .H, or Kd 2 3 .H 2 0. This compound may be 
 
 D D 4 
 
408 ARSENIC-RADICLES (ORGANIC). 
 
 prepared by passing oxygen gas for several days through alkarsin ; the greater part of the 
 liquid is then converted into crystals of cacodylic acid, which may be purified by pressure 
 between paper and recrystallisation. This mode of preparation, however, is disagree- 
 able and dangerous, on account of the inflammability and poisonous character of the 
 cacodyl. A safer and more expeditious method is to oxidise alkarsin with mercuric 
 oxide. The two substances are placed together under water, in a vessel externally 
 cooled ; mercury is thereby reduced, and cacodylate of mercury formed : 
 
 Kd + 2Hg 2 = 3Hg + Kd0 2 Hg. 
 
 More alkarsin is then added, drop by drop, till mercury no longer separates on heating 
 the mixture, and a faint odour of cacodyl becomes perceptible ; after which the liquid 
 is evaporated, the residue dissolved in alcohol, and the cacodylic acid which crystallises 
 from the solution is purified by recrystallisation from alcohol. It is then obtained in 
 large oblique rhomboidal prisms, transparent and colourless. It is inodorous and not 
 at all poisonous, although it contains 54 -35 per cent, of arsenic. It dissolves in water 
 in all proportions, somewhat less freely in alcohol, and is insoluble in ether. It is 
 permanent in dry air, but damp air decomposes it. It is altogether a very stable 
 compound, sustaining a heat of 200 C. without decomposition ; at higher tempera- 
 tures however, it decomposes, yielding arsenious oxide and other arsenical products 
 having a very fetid odour. It is not attacked by fuming nitric acid, or by a mixture 
 of sulphuric acid and chromate of potassium, even at the boiling heat. It is not deoxi- 
 dised by sulphurous acid, oxalic acid, ferrous sulphate, or hydrogen gas ; but when 
 heated with phosphorous acid, it gives off vapours of cacodyl. It is also reduced when its 
 aqueous solution is boiled with zinc. An acid solution of protochlortde of tin converts it 
 into chloride of cacodyl. Dry hydriodic acid gas, passed over dry cacodylic acid, forms 
 iodide of cacodyl, water, and free iodine : 
 
 Kd0 2 H + SHI = Kdl + 2H 2 + 21. 
 
 Dry hydrobromic acid gas acts in a similar manner. With dry hydrochloric acid, on 
 the contrary, or with the concentrated aqueous acid, cacodylic acid unites directly, 
 forming the compound Kd0 2 H.ClH. But by exposing cacodylic acid for some time to 
 a stream of hydrochloric acid gas, dichloride of arsenmonomcthyl is obtained, together 
 with water and chloride of methyl. (Baey er) : 
 
 As(CH 3 ) 2 2 H + 3HC1 = AsCIFCl 2 + 2H 2 + CH 3 C1. 
 
 Sulphydric acid, either dry or in aqueous solution, decomposes cacodylic acid, with 
 rise of temperature, forming disulphide of cacodyl, water, and sulphur : 
 
 2Kd0 2 H + 3H 2 S = 2KdS + 4H 2 + S; 
 
 but if the cacodylic acid is dissolved in weak alcohol, a considerable quantity of proto- 
 sulphide is formed as well as disulphide : 
 
 2Kd0 2 H + 3H 2 S = Kd 2 S + 4H 2 + 2S. 
 
 Cacodylates. Cacodylic acid dissolves metallic oxides, and decomposes carbonates 
 with effervescence. Most of its salts are gummy, but few being capable of crystal- 
 lising. The general formula of the normal cacodylates is AsC 2 H 6 M0 2 = KdO'-M. 
 They require a higher temperature to decompose them than the acid, and give off 
 stinking products, leaving a residue of carbonate or arsenate. They dissolve in water 
 and in alcohol. Sulphydric acid converts them into the corresponding sulpho-cacody- 
 latcs KdS 2 M. "With silver, cacodylic acid forms a normal salt, Kd0 2 Ag, and an acid 
 salt, Kd0 2 Ag.2Kd0 2 H, both of which crystallise in needles. 
 
 Cacodylic acid also combines with certain acids. 
 
 Hydrochlorate of cacodylic acid, Kd0 2 H.ClH, called by Bunsen, basic perchloride of 
 cacodyl, is obtained by dissolving cacodylic acid in concentrated hydrochloric acid, and 
 evaporating in vacuo. It then solidifies in a mass of beautiful lamellated crystals, in- 
 odorous, but having a strong acid taste (Bun sen). It is also produced by the action 
 of water or alcohol on trichloride of cacodyl (Baeyer, p. 406). The compound is 
 decomposed by water into hydrochloric and cacodylic acids, and when heated to 
 200 C. gives off monochlorinated hydride of methyl, water, hydrochloric acid, and 
 an oily liquid, leaving a residue of arsenious acid. 
 
 On mixing the alcoholic solutions of cacodylic acid and mercuric chloride, a caco- 
 dylate of mercuric chloride, Kd 2 3 .2HgCl, is precipitated in white shining scales, 
 which change after a while to slender needles. 
 
 Hydrofluoric acid forms with cacodylic acid a similar compound, Kd0 2 H.FH, which 
 crystallises in fine prisms. Hydrobromic acid also unites directly with cacodylic acid, 
 but the compound is a syrupy liquid which does not crystallise. 
 
 Selenide of Cacodyl, is obtained by distilling chloride of cacodyl two or three 
 times with aqueous selenide of sodium. It passes over with the vapour of water, in 
 the form of a heavy yellow oil, having an extremely offensive odour. It is insoluble 
 
ARSENIDES OF METHYL. 409 
 
 in water, but soluble in alcohol and ether. It has a very high boiling point. ^ It forms 
 black precipitates with lead and silver salts, and with mercuric chloride, it yields first 
 a black precipitate of sulphide of mercury, and afterwards, on further addition of the 
 mercury-salt, a copious precipitate of chloromercurate of cacodyl. 
 
 Sulphide of Cacodyl,As-C 2 II 6 S = Kd 2 S, may be prepared by adding a solution of 
 sulphide of barium to the crude liquid obtained by distilling acetate of potassium with 
 arsenious oxide, or by distilling sulphydrate of barium with chloride of cacodyl. It is 
 purified by means of carbonate of lead and chloride of calcium. It is a transparent, 
 colourless, extremely fetid liquid, which retains its fluidity at 40 C., and boils at a tem- 
 perature considerably above 100, yielding a vapour of specific gravity 7*72. It is nearly 
 insoluble in water, but mixes in all proportions with alcohol and ether. It does not 
 fume in the air, but rapidly absorbs oxygen, being converted into dioxide and disul- 
 phide of cacodyl : 
 
 Kd 2 S + = KdO + KdS. 
 
 Hydrochloric acid converts it into chloride of cacodyl, with evolution of sulphydric 
 acid. 
 
 Disulphide of Cacodyl, KdS, or Sulphocacodylate of cacodyl, K( j|S 2 . Obtained by 
 
 the action of sulphur on cacodyl, or on the monosulphides, or by treating cacodylic acid 
 with sulphuretted hydrogen in a vessel externally cooled. Disulphide of cacodyl then 
 separates, mixed with excess of sulphur, from which it may be separated by solution 
 in boiling alcohol. The solution, if slowly cooled, deposits the disulphide in large 
 rhombic tables, but if quickly cooled, in small prisms, soft and greasy to the touch. 
 The compound has a pungent odour, like that of asafoetida, is permanent in the air, 
 and melts at 50 C., forming a colourless liquid, which solidifies in a crystalline mass on 
 cooling. It is insoluble in water, but dissolves readily in alcohol, very sparingly in 
 ether. It dissolves in hydrochloric acid without alteration ; in strong sulphuric acid, 
 with evolution of sulphurous acid and separation of sulphur. Nitric acid and peroxide 
 of lead convert it into cacodylic acid. Mercury decomposes it, forming protosulphide 
 of cacodyl, and sulphide of mercury. 
 
 Sulphocacodylic acid, AsC 2 H 7 S 2 = KdS 2 H. This acid has not been obtained in 
 the free state, but its salts, KdS 2 M, are obtained by precipitating the alcoholic solution 
 of the disulphide with alcoholic solutions of certain metallic salts, or by decomposing 
 the cacodylates with sulphydric acid. The lead-salt, KdS 2 Pb, forms small white 
 pearly scales, which are indorous, permanent in the air, not affected by sulphydric 
 acid, insoluble in water, nearly insoluble in alcohol. The cuprous salt, KdS 2 Ccu, 
 [Ccu = Cu 2 ], is obtained by adding an alcoholic solution of cupric nitrate to a large 
 excess of alcoholic disulphide of cacodyl, cacodylic acid and nitrate of cacodyl being 
 formed at the same time : 
 
 4KdS + 2N0 3 Cu + 2H 2 = 2KdS 2 Cu + KdO'H + N0 3 Kd + N0 3 H. 
 It is a soft, loose, egg-yellow powder, which is decomposed by heat, and is insoluble 
 in water, aqueous acids, alcohol, and ether. The antimony-salt, Kd 3 S 6 Sb (Sb being equi- 
 valent to H 3 ), crystallises in short light yellow needles, difficult to purify. The 
 bismuth-salt, Kd 3 S 8 Bi, forms delicate, golden-yellow, inodorous scales, which are per- 
 manent in the air, sustain a heat of 100 C. without decomposition, and are not affected 
 by sulphydric acid. They are insoluble in water, and nearly insoluble in alcohol 
 and ether. The gold-salt, KdS 2 Au, is obtained by mixing the alcoholic solutions of 
 disulphide of cacodyl and trichloride of gold, cacodylic acid being formed at the same 
 time, as a soft, yellowish white, tasteless, inodorous powder, which is set on fire by 
 strong nitric acid, with separation of sulphur and gold. It is decomposed by caustic 
 potash, but not by sulphydric acid. Insoluble in water, hydrochloric acid, alcohol and 
 ether. 
 
 ARSENTRIMETHYL As(CH 3 ) 3 and ARSENMETHYLITJM As(CH 9 ) 4 . (Cahours and 
 Riche, Compt. rend, xxxix. 541.) When iodide of methyl is dropped by small portions 
 into a small flask filled with carbonic anhydride and containing pulverised arsenide of 
 sodium, a considerable degree of heat is developed ; and if the additions of iodide of 
 methyl be repeated till no further rise of temperature is produced, and the mixture be 
 then distilled in a current of carbonic anhydride, four products are obtained, viz. unal- 
 tered iodide of methyl, a white crystalline body, and a heavy liquid composed of two dis- 
 tinct compounds, one of which boils at 120 C., the other between 165 and 170. The 
 former is arsentrimethyl ; the latter arsendimethyl or cacodyl. The quantity of these 
 liquids obtained is but small, even when the matter operated upon amounts to 100 
 grammes. 
 
 Arsentrimethyl is obtained pure by the decomposition of iodide of arson- 
 
410 ARSENIC-RADICLES (ORGANIC.) 
 
 methylium, e.g. by treating the compound of iodida of arsenmethylium and iodide of 
 arsenic (vid. inf.') with boiling potash-ley, evaporating to dryness, and distilling in ' 
 an atmosphere of carbonic anhydride. It is a colourless mobile liquid, boiling below 
 100 C. It is diatomic. The oxide, AsMe 3 0, is crystallisable but deliquescent. The 
 sulphide, AsMe s S crystallises from aqueous or alcoholic solution by slow evaporation 
 in colourless prisms. It unites already with iodine and bromine, forming the com- 
 pounds AsMe 8 ! 2 and AsMe 3 Br 2 . (C ah ours, Compt. rend, xlix 87; Jabresber. 
 d. Chem. 1869, 431.) 
 
 Iodide of Arsenmethylium. This is the crystallised body just mentioned, 
 which is in fact the chief product of the reaction. It may also be obtained by the 
 action of iodide of methyl upon cacodyl. On mixing these two liquids in a tube, a 
 violent action takes place, and a yellowish white mass of crystals of iodide of ar.sen- 
 methylium is obtained, impregnated with an oily matter of the same colour, consisting 
 of iodide of cacodyl : 
 
 2CH'I + 2As(CH 3 ) 2 = As(C 2 H 8 ) 4 I + AsC 2 H 6 .I. 
 
 The crystals, freed from the oil by draining and pressure between bibulous pap^r, and 
 then dissolved in iodide of methyl mixed with alcohol, separate from the solution in 
 the form of beautiful colourless tables having a high lustre. 
 
 Iodide of arsenmethylium boiled with recently precipitated oxide of silver, yields a 
 strongly alkaline liquid, which, when evaporated in vacuo, yields very deliquescent 
 crystalline laminae consisting of the hydrated oxide of arsenmethylium ; and its solution 
 mixed with sulphate or nitrate of silver, yields iodide of silver, and sulphate of arsen- 
 methylium, S0 4 (AsMe 4 ) 2 , or the nitrate, NO'AsMe 4 . These salts are very soluble, highly 
 deliquescent, and separate from their solutions by evaporation in vacuo, in the form of 
 beautiful crystals. 
 
 Iodide of Arsenmethylium with Tri-iodide of Arsenic As(CH 3 ) 4 I.AsP. 
 When iodide of methyl is heated to 200 C., in contact with metallic arsenic, the latter 
 disappears, and a large quantity of orange-red tabular crystals are obtained, moistened 
 with a brownish liquid. 
 
 The crystals are decomposed by distillation, yielding an oil which has a penetrating 
 odour and excites tears. This oil is a mixture of several substances, the least volatile 
 of which boils at 170 C., has the composition of iodide of cacodyl, and yields cacodyl 
 when distilled with amalgam of zinc ; the more volatile portion deposits long white 
 very beautiful needles, isomeric with iodide of cacodyl. 
 
 'Iodide of Arsenmethylium and Zinc, As(CH 3 ) 4 I.ZnI, is obtained in colour- 
 less crystals by heating iodide of methyl with arsenide of zinc. It is decomposed 
 by boiling with potash-ley, a heavy oil separating, which solidifies on cooling, and if 
 this mass be exposed to the air till the free potash is converted into carbonate, then 
 exhausted with absolute alcohol, and the alcohol left to evaporate, iodide of arsen- 
 methylium crystallises out in prisms. (C a hours, Compt. rend. xlix. 87.) 
 
 Iodide of Arsenmethylium and Cadmium, As(CH 3 ) 4 LCdI, is obtained in 
 like manner and exhibits similar properties. (Cahours.) 
 
 Tri-iodide of Arsenmethylium, As(CH 3 ) 4 ! 3 . Analogous to tri-iodide of tetr- 
 ethylium. (Cahours.) 
 
 Bromide of Arsenmethylium. Bromide of methyl acts energetically on 
 cacodyl, yielding bromide of arsenmethylium in beautiful, very deliquescent crystals, 
 and liquid bromide of cacodyl. (Cahours and R i c h e. ) 
 
 ABSENDIMETHYL-DIETHYLIUM. As(CH 3 ) 2 (C 2 H 5 ) 2 = AsMe 2 E a . (Cahours and 
 Kiche, Compt. rend xxxix. 544.) 
 
 This radicle, like the preceding, has not been obtained in the free state, but the 
 sulphide, iodide, bromide, and chloride are formed, together with the corresponding 
 compounds of cacodyl, by the action of sulphide, iodide, &c., of ethyl on cacodyl. 
 
 Iodide. As(CH 3 ) 2 (C 2 H 5 ) 2 L When iodide of ethyl is mixed with cacodyl, no 
 apparent change takes place at first ; but the mixture, when left to itself, gradually 
 deposits magnificent crystals of iodide of arsendimethyldiethylium, and likewise yields 
 an oil consisting of iodide of cacodyl : 
 
 2EI + 2AsMe 2 = AsMe 2 E 2 I + AsMe 2 !. 
 
 Bromide and Chloride of ethyl act in a similar- manner, but more slowly. To obtain 
 chloride of arsenmethethylium, the mixture must be heated in sealed tubes to 180 
 or 200 C. ; it then deposits an oil containing needle-shaped crystals of the chloride. 
 On distilling the oil and leaving the distillate to cool, these crystals separate in largo 
 
ARSENIDES OF METHYL. 411 
 
 quantity. Chloride of arsendimethyldiethylium forms crystalline compounds with 
 chloride of mercury, trichloride of gold, and dichloride of platinum. 
 
 The Hydrate is formed by treating a solution of the iodide with oxide of silver; a 
 strongly alkaline liquid is then obtained, which, when evaporated, deposits the oxide 
 in very deliquescent crystalline scales. 
 
 Sulphide. Sulphide of ethyl acts very slowly on cacodyl, and only when heated, 
 forming crystalline sulphide of arsendimethyldiethylium and a yellowish oil, consisting 
 of sulphide of cacodyl. 
 
 The Sulphate and Nitrate are obtained in the form of very deliquescent 
 crystals, by treating the solution of the iodide with sulphate or nitrate of silver. 
 
 ARSENTRIMETHYL-ETHYLIUM, AsMe s EI, and ARSENMETHYL-TRIETHYLITJM, 
 AsMeE*. The iodides of these radicles are obtained by treating arsentrimethyl with 
 iodide of ethyl, and arsentriethyl with iodide of methyl respectively. Both are 
 isomorphous with the iodides of arsentetramethylium and arsentetrethylium. 
 
 ARSENDIMETHYL-DIAMYLIUM, As(C 2 H 3 ) 2 (C 5 H n ) 2 = AsMe 2 Am 2 . The iodide of 
 this radicle is produced, together with iodide of cacodyl, by heating cacodyl with iodide 
 of amyl to 180 C. for two or three days. It crystallises either in nacreous needles, or 
 in thin plate?. Treated with oxide, nitrate, and sulphate of silver, it yields the oxide, 
 nitrate, and sulphate of arsendimethyldiamylium. (Cahours and Riche.) 
 
 The arsenides of methyl and their compounds are related to one another by the fol- 
 lowing law. If we arrange them in two groups, the one formed on the type of chloride 
 of ammonium, NH 4 C1, the other on that of ammonia, NH 3 , as in the following tables, 
 we find that each member of the second column may be derived from the one next 
 above it in the first, by abstraction of chloride of methyl ; and each member in the first 
 column except the highest, may be formed from the one next above it in the second, 
 by addition of 2 atoms of chlorine, the series extending from chloride of arsentetrame- 
 thylium to trichloride of arsenic : 
 
 Type NH'Cl. Type NH 3 . 
 
 As Me Me Me Me Cl As Me Me Me 
 
 As Me Me Me Cl Cl As Me Me Cl 
 
 As Me Me Cl Cl Cl As Me Cl Cl 
 
 As Me Cl Cl Cl Cl As Cl Cl Cl 
 
 All the reactions indicated in this table have been actually observed, excepting the 
 resolution of AsMe 4 Cl into AsMe 3 and MeCl, and that of AsMe 3 Cl 2 into AsMe 8 Cl and 
 MeCl ; but a decomposition analogous to the former of these, appears to take place in 
 the preparation of the iodides of the arsenmethyls and arsenethyls, the iodide of arsen- 
 
 into iodide of ethyl 
 and triethylamine. 
 
 There is also another relation to be observed between these compounds, viz. that 
 each of them may be derived from the one immediately above it in the same column, 
 by substitution of chlorine for methyl; and hence it appears that AsMe 4 is monatomic ; 
 AsMe 3 diatomic ; AsMe 2 either monatomic or triatomic ; and AsMe either diatomic or 
 tetratomic ; just as in chloride of propyl, C 3 H 7 C1, the radicle C 3 H 7 replaces 1 at. hydro- 
 gen, whereas in chloride of propylene, C 3 H 6 C1 2 , derived from the former by substitution 
 of 1C1 for 1H, the radicle C S H 6 takes the place of 2 atoms of hydrogen ; and in tri- 
 chlorhydrin, C 3 H 5 C1 3 , the next term in the same series, C 3 H 5 (glyceryl), takes the 
 place of 3 at. H. Moreover, just as the group C 3 H 5 is monatomic in the allyl-com- 
 pounds, and triatomic in the glyceryl-compounds, so likewise As(CH 3 ) 2 is sometimes 
 monatomic and sometimes triatomic. The analogy between the two series of com- 
 pounds will be more clearly seen from the following tabular view : 
 
 As(CH 3 ) 2 . Cl C 8 H 7 . Cl 
 
 As(CH 3 ) 8 . Cl 2 C 3 H 8 . Cl 3 
 
 As(CH 3 ) 2 . Cl 3 C"H 5 . Cl 3 
 
 As(CH 3 ) 2 Cl. C 3 H 5 . Cl. 
 
 Similar analogies may be traced in the compounds of arsenic and ethyl, and like- 
 wise, though not yet quite so clearly, in the compounds of antimony, bismuth, and 
 phosphorus, with the alcohol-radicles. (Baeyer.) In fact, the compounds of these 
 metalloi'dal radicles may, in almost all cases, be reduced to the general types MR 3 
 M 2 E 3 , MR 5 , M"R 5 , where M stands for P, As, Sb, or Bi ; and the 3 or 5 at, R are made 
 
412 ARSENIDE OF TETRYL ARTIIANITIN. 
 
 up, partly by an alcohol-radicle, partly by an equivalent quantity of chlorine, iodine, 
 oxygen, sulphur, &c. (See ORGANO -METALLIC BODIES.) 
 
 Arsenide of Tetryl. Tetryl- or Butyl-cacodyl. Cacodyl of Valeric Acid. 
 When valerate of potassium is distilled with an equal weight of arsenious oxide, a 
 heavy yellowish oil passes over, which has a penetrating alliaceous odour, fumes 
 copiously in the air, but does not take fire spontaneously. It is soluble in water, forma 
 a thick white precipitate with mercuric chloride, and appears to reduce mercuric oxide 
 to the metallic state. When left for some time in a loosely closed vessel, it changes 
 entirely into a mass of large, hard, shining, nearly colourless, prisms, which, after 
 drying between filtering paper, are destitute of odour. They have an acid reaction, 
 dissolve in water, and are completely decomposed by nitrate of silver. (Gribbs, Sill. 
 Am. J. [2] xv. 118.) 
 
 Arsenide of Trityl. Trityl- or Propyl-cacodyl. Cacodyl of Butyric Acid. By 
 distilling equal weights of butyrate of calcium and arsenious oxide, shaking up the 
 distillate with magnesia and water, and rectifying, a heavy colourless oily liquid is 
 obtained, which has a disgusting cacodyl-odour, does not fume in the air, but burns 
 when set on fire with a white flame and arsenical smoke. The watery liquid which 
 passes over with the oil, appears to contain a considerable quantity of it, and gives a 
 white precipitate with mercuric chloride, the cacodyl-odour being at the same time 
 destroyed. The precipitate dissolves on heating the liquid, but reappears in small 
 crystals on cooling. On mixing the solution and the crystals with hydrochloric acid 
 and zinc, the odour of cacodyl reappears, the evolved hydrogen gives off thick white 
 fumes in the air, and deposits an orange-coloured substance on cold bodies. The 
 mixture when heated yields a colourless foetid oil, which fumes in the air, but is not 
 spontaneously inflammable. (Wo'hler, Ann. Ch. Pharm. Ixviii. 127.) 
 
 ARSEKTXOSXDZiRXTZ:. Arsenocrocite. A hydrated ferrico-calcite arsenate, 
 occurring at Komaneche, near Macon, in spherical masses of fibrous texture and yellow 
 colour. Its exact composition has not been determined. 
 
 ARSEXTXTE or ARSENOIiXTE. Arsenic bloom. Native Arsenious Oxide. 
 A rare mineral, generally occurring in needle-shaped or capillary crystals, also massive, 
 with spherical and botryoidal surface ; very rarely in regular octahedrons. Specific 
 gravity = 3*69 to 3'71. Hardness = 1-5. It consists of arsenious oxide more or less 
 pure, has a white to greyish- white colour, occasionally yellow, red, or green ; sometimes 
 covered with a blackish crust (? suboxide or a mixture of arsenious oxide with metallic 
 arsenic). It is translucent, with vitreous to silky lustre. It is found, accompanying 
 ores of silver, lead, arsenical iron, cobalt, nickel, &c., at Andreasburg in the Harz; 
 also at Joachimsthal in Bohemia, Kapnik in Hungary, and in the old mines of Biber 
 inHanau. (Dana, ii. 139.) 
 
 ARSENCMEX.AN-X;. See BINNITE. 
 
 ARS2NOPYRITE. Syn. with MlSPICKEL. 
 
 ARSEZffOSXDXiRXTX:. Native diarsenide of iron. (See IBON, ARSENIDES OF.) 
 URSEWPHYXilITE. Breithaupt's name for a mineral which, according to him, 
 has the composition of arsenious oxide, but crystallises in forms of the trimetric 
 system, isomorphous with valentinite. The trioxides of arsenic and antimony are 
 therefore isodimorphous. 
 
 ARSXDOGXiXtr. The name given byL. G-melin (Handb. ix. 315), to the hypo- 
 thetical compound AsH 2 (= Ar), analogous to amidogen, NH 2 , formerly supposed 
 by Laurent, Gerhardt, and Dumas, to exist in cacodyl and its derivatives. Accord- 
 ing to this view, cacodyl was supposed to be the hydride of a compound, C*ArIf 3 , 
 analogous to ethylene, viz. C 4 ArH 3 .H; oxide of cacodyl = &ArH*.HO; the proto- 
 sulphide == C*ArH 3 .HS, &c. 
 
 ARTHA7TXTXN', or CYCXi AMX1U, a crystalline substance extracted by Saladi n 
 (J. Chirn. med. vi. 417), from the roots of Cyclamen Europceum (Arthanita officinalis). 
 It is said also to exist in small quantity in the roots of the cowslip (Primula vcris), 
 of Anagallis arvensis, and Limosclla aquatica. It is prepared by digesting the fresh 
 roots of cyclamen with alcohol, evaporating the extract, and treating the residue, first 
 with ether, then with cold water : the insoluble part constitutes arthanitin. It is 
 purified by recrystallisatiou from alcohol, with the aid of animal charcoal. It crys- 
 tallises in fine colourless needles, which are inodorous, but have a strongly acrid and 
 styptic taste. It is neutral to vegetable colours, dissolves in 500 pts. of water, readily 
 in alcohol. It is altered at the temperature of boiling water, becoming less soluble in 
 alcohol. Nitric acid transforms it into oxalic acid. Sulphuric acid communicates to 
 it a violet-red tint. Taken internally, arthanitin acts like a purgative, and produces 
 vomiting. 
 
ARTICHOKE ASAFCETIDA. 413 
 
 ARTICHOKE. According to Verdeil (Compt. rend. xli. 588), the green colour- 
 ing matter of the artichoke ( Cynara scolymus) and other composite plants, is a sub- 
 stance distinct from chlorophyll, and is formed by the action of the air, water, and 
 ammonia, on the comminuted parts of the plants. The liquid, which has a fine green 
 colour, forms with acetic acid a bulky green precipitate, which resembles indigo when 
 dry, but when treated with aqueous alkalis, again forms solutions of a beautiful green 
 colour. 
 
 The artichoke yields, according to Eichardson (Ann. Ch. Pharm. Ixvii. Table), 
 in the fresh state, M7 per cent, of ash; in the dry state, 6'2 per cent. In the roots, 
 stems, and leaves of the Jerusalem artichoke (Helianthus tuberosus) Way and Ogston 
 (Journ. of Agric. Soc. vii. [2] 593) found in the fresh state, 179, 1'94, and 15-00 per 
 cent, of ash; in the same parts when dried, 12-2, 4-4, and 28'3 per cent. The con- 
 stituents of the ash are given in the following table : 
 
 Artichoke. Jerusalem Artichoke. 
 
 Root. Stem. Leaves. 
 
 Potash . . . 24-0 . . 55-9 . . 38-4 . . 6-8 
 
 Soda .... 5-5 .. 07 .. 37 
 
 Lime 9-6 . . 3'3 . 20'3 . . 40'1 
 
 Magnesia . . . 4'1 .1-3. . 1'9 .20 
 
 Sulphuric acid (SO 3 ) . 5'2 . . 3-8 . 3-2 . . 2-0 
 
 Carbonic acid (CO 2 ) . . . 11-8 . . 25-4 . . 24-3 
 
 Phosphoric acid (P 2 5 ) 36-2 . . 167 . . 30 . . 0-6 
 
 Silica . . . . 7-0 . .1/5. 1'5 . . 17'5 
 
 Sesquioxide of iron . 0'5 . . 0'9 I'l 
 
 Chloride of potassium . 5'0 
 
 Chloride of sodium .3-6.. 47 1'8 
 
 Sesquiphosphate of iron 4'8 
 
 ARTOCARPUS Z2TCISA. The fruit of this tree, the bread-fruit tree, which 
 grows in the islands of the East Indian Archipelago, contains 14 per cent, of starch, 
 3 per cent, albumin, 19 gluten and woody fibre, and 63 water. 
 
 ARUM ESCUIiESTTUZVT. The fresh tubers of this plant yield, according to 
 T. J. Herapath (Chem. Soc. Qu. J. iii. 193), T65 per cent, ash, containing in 
 100 pts. : 617 pts. soluble in water, and consisting of 45'1 K 2 ; 8'1 NaCl ; 3-8 SO 3 ; 
 47 P 2 5 ; and 387 pts. insoluble in water, consisting of 18'3 K 2 ; 1*1 Fe<0 3 ; 
 11-4 P 2 5 , 6-1 SiO 2 . 
 
 ARUIVI MACTJXi ATU1VT. The fresh plant contains a sharp milky juice, which pro- 
 duces inflammation of the skin, but is so volatile and unstable that it is no longer present 
 in the dried root. The dry root is said to contain 71 per cent, starch, together with 
 23 per cent, gum and vegetable mucus. 
 
 ARUCTDO FHRAGIVXXTES. The dry plant yields 47 per cent, of ash, which 
 according to Schulz-Fleeth (Pogg. Ann. Ixxxiv. 80), contains in 100 pts.: 8'6 K 2 0' 
 5-9Ca 2 0; l-2Mg 2 0; 0-2Fe 4 3 ; 2-8S0 3 ; 71'5Si0 2 ; 6-6 CO 2 ; 2'0 P*0 5 ; 0-4NaCi; 
 
 ASA DULCIS. See BENZOIN. 
 
 ASAFCETXDA. Gummi ASGB Jcettdcs, StinJcasant, TtufclsdrecTc. A gum-resin 
 extracted from the root of the Ferula Asafoetida, an umbelliferous plant growing in 
 Persia. The root, which is black on the outer surface, resembles a large parsnep. On 
 cutting it transversely, the asafoetida exudes in the form of a white juice, like cream, but 
 on exposure to the air, it gradually becomes yellow and at last dark brown. It is very 
 apt to run into decomposition ; hence, those who collect it carefully defend it from the sun. 
 The fresh juice has an excessively strong smell, which grows weaker and weaker upon 
 keeping ; a single dram of the fresh fluid smells more than a hundred pounds of the 
 dry asafoetida brought to us. The Persians are commonly obliged to hire ships on 
 purpose for its carriage, as scarcely any one will receive it along with other commo- 
 dities, its stench infecting everything that comes near it. 
 
 Asafoetida is met with, sometimes in small drops or tears, but more frequently in 
 reddish masses with white streaks. Specific gravity 1-327. Its recently fractured 
 surface has but little colour, but quickly reddens on exposure to the air. It is friable 
 at very low temperatures, but softens at the heat of the hand. It dissolves in alcohol 
 much more readily than in water. It has an extremely disagreeable alliaceous 
 odour, and a sharp biting taste. It contains in 100 pts., according to Pelletier 
 (Bull. Pharm. iii. 556), 65-0 of resin, 19-4 soluble gum, 11-2 bassorin, 3-6 volatile 
 oil, and 0'3 of malate of calcium. According to Johnston (Phil. Mag. Dec. 1838) 
 the resin of asafcetida, which may be extracted by alcohol, is of a light yellow colour, 
 
414 ASAFOETIDA ASARUM. 
 
 when pure, but becomes purple on exposure to the sun. It contains about 70-2 
 per cent, of carbon, 7'6 of hydrogen, and 22 - 2 of oxygen; no sulphur. Asafcetida 
 is used as a remedy in nervous and hysteric affections, as a deobstruent, and 
 sometimes as an anthelmintic. It is said to be used also by some Asiatic tribes as a 
 condiment. 
 
 Oil of Asafcetida. Asafcetida distilled with water yields about 3 per cent, of a 
 sulphuretted essential oil, to which its odour is due. This oil is neutral, begins to boil 
 between 135 and 140 C., and when left at rest, gives off a considerable quantity 
 of sulphydric acid. HI a si we tz (Ann. Ch. Pharm. Ixxi. 23) obtained from it by ana- 
 lysis, from 64-2 to 69'3 per cent, carbon, from 9'1 to 10'5 percent, hydrogen, and 20-2 
 to 25-5 per cent, sulphur, its composition varying with the time elapsed since its 
 preparation. Hlasiwetz regards it as a variable mixture of the two compounds 
 C^H^S' and C 12 H-S. When it is treated with oxide of silver, sulphide of silver 
 is formed, and the liquid, if afterwards rectified, contains 6 5 -6 per cent. C, 13'1 H, 
 and 24'8 S. On agitating it with strong solution of potash and hydrate of lead, and 
 then rectifying, an oil is obtained having an odour of lavender or rosemary, and con- 
 taining about 6O7 per cent. C, 9'5 N, and 29*85 S. An oil having the same compo- 
 sition is obtained by passing sulphurous acid gas through the crude oil. 
 
 The alcoholic solution of oil of asafcetida forms with dichloride of platinum, yellow 
 or brown precipitates varying in composition, according to the strength of the solutions 
 and the duration of the action, but all containing the same proportions of. carbon and 
 hydrogen as the oil itself, viz. C 6 H n . 
 
 On mixing concentrated alcoholic solutions of oil of asafcetida and chloride of mer- 
 cury a white precipitate is formed, which is partly dissolved by boiling alcohol ; and 
 the solution on cooling yields microscopic crystals containing 2C ti H"S.5Hg 2 S + 
 2C 6 H II Cl 2 .HgCl. The portion of the precipitate insoluble in alcohol, blackens when 
 treated with potash, a proof that it contains mercurous chloride : it was found to 
 contain C 6 H 11 S 4 .Hg 2 S.4Hg 2 C1.4Hg 3 SCl. Both these mercury-compounds, when treated 
 with sulphocyanate of potassium, yield a volatile oil smelling like oil of mustard, and 
 like that oil, forming a crystalline compound with ammonia : it does not however 
 contain allyl, but probably the homologous radicle, C 6 H U (Hlasiwetz, Hand. d. Chem. 
 2 te Aufl. ii. 339.) 
 
 ASARXN or ASARONE, C 20 H 26 5 . This substance is contained in the root of 
 asarabacca (Asarum europ&um) and passes over in the crystalline form when the dry 
 root is distilled with water. The crystals belong to the monoclinic or oblique pris- 
 matic system, and resemble camphor in taste and odour. Asarone melts at 40 C., begins 
 to boil at 280, and may be sublimed in small quantity between two watch-glasses. 
 It is insoluble in water, but dissolves readily in alcohol, ether, and essential oils. 
 When it is boiled for some time with alcohol, the solution gradually turns red, and a 
 portion of the asarone is converted into an uncrystallisable, resinous, isomeric modfica- 
 tion, which does not distil with vapour of water, and decomposes at 300 C. Nitric 
 acid converts asarone into oxalic acid. It is dissolved with red colour by strong sul- 
 phuric acid, and reprecipitated by water. It is strongly attacked by chlorine, giving 
 off hydrochloric acid, and yielding a thick oil whose composition approximates to the 
 formula C 20 H 22 C1 4 5 . (Goertz, Pfaff's System d. Materia Medica, iv. 229 ; Blanchet 
 and Sell, Ann. Ch. Pharm, vi. 296; Schmidt, ibid. liii. 156.) 
 
 AS ARXTE. A camphor-like substance found, together with asarone, in the root of 
 Asarum europu&m, and resembling that substance in many respects, but differing from 
 it in appearance, in not decomposing so readily when sublimed, but chiefly in its melting 
 point which is 70 C. whereas that of asarone is 40. It is obtained by dissolving in 
 alcohol the impure crystals of asarone as they are obtained by distilling the root with 
 water, precipitating by alcohol, and collecting the small silky crystals which float 
 about in the liquid. Grager, who obtained this substance at first, regarded it as a 
 distinct body, but was afterwards disposed to regard it as identical with asarone : the 
 difference in the melting point is, however, too great to be accounted for by error of 
 observation. Blanchet and Sell suppose it to be the solid part of asurum-oil, and 
 asarone a product of the decomposition of that oil. 
 
 ASARUIVl-OZZi. A volatile oil existing in small quantity (about yl^) in the root 
 of Asarum europceum, and passing over, together with asarone, when the root is distilled 
 with water. It may be separated from the asarone by treating the oily portion of the 
 distillate with a small quantity of alcohol. Two layers then form, the upper being 
 an alcoholic solution of asarone, containing a little of the oil ; the lower, a solution of 
 small quantities of asarone and alcohol in the oil. On distilling this lower liquid over 
 hydrate of lime, and leaving the distillate to stand for some time, the asarone sepa- 
 rates out, and the remaining oil may be dehydrated by chloride of calcium. The 
 
ASBESTOS ASBOL1NE. 415 
 
 oil is yellowish and viscid, smells like valerian oil, has a sharp burning taste, is lighter 
 than water, sparingly soluble in water, but easily soluble in alcohol, ether, and in oils 
 both fat and volatile. Blanchet and Sell (Ann. Ch. Pharm. vi. 296) deduce from 
 their analysis (74-4 C, and 97 H) the formula C 8 H 9 0, which does not agree very 
 well with it: the formula C'H 15 2 , is more in accordance with the analysis. As, how- 
 ever, the oil doubtless still contained asarone, it is useless to attempt to determine its 
 formula exactly till further experiments are made. It appears, however, to contain 
 more carbon and hydrogen than asarone, which therefore may have been formed from 
 it by oxidation. 
 
 ASBESTOS, or ASBESTTTS. (a0-)8e<rros, indestructible.) A mineralogical term 
 used rather to denote a peculiar form assumed by several minerals, than to designate 
 any particular species. It is, in fact, applied to several varieties of amphibolic and 
 augitic minerals, such as actinolite, tremolite, anthophi/llite, &c. which occur in long 
 capillary crystals, placed side by side in a parallel position, thus producing a fibrous 
 mass. These conditions may be fulfilled in various degeees, and there are accordingly 
 various kinds of asbestos. Those varieties whose fibres are very delicately and regu- 
 larly arranged, are called flexible asbestos, or amianth (a Greek term, signifying unpol- 
 luted} ; the individual crystals are easily separated from each other, are very- 
 flexible and elastic, and have a white or greenish colour, with a fine silky lustre. A 
 single fibre of this mineral fuses readily into a white enamel ; but in the mass, it is 
 capable of resisting ordinary flame, so that when woven it produces a fire-proof cloth. 
 The most beautiful specimens are found in the Tarantaise in Savoy, and in Corsica, 
 where it occurs very abundantly. It is also found near Barege in the Pyrenees, in 
 Dauphiny, and on the St. Gothard ; at St. Neverne in Cornwall ; at Portsoy in Scotland ; 
 in mica slate at Glenelg, Inverness-shire ; and near Durham. Those varieties in which 
 the crystals are coarser, with scarcely any flexibility, are called common asbestos. 
 There are also three other varieties, called mountain leather, mountain cork, and 
 'mountain wood, which differ from common asbestos by the fibres interlacing each 
 other. 
 
 Common asbestos occurs in masses of fibres of a dull greenish colour, and of a 
 somewhat pearly lustre. Fragments splintery. It is scarcely flexible, and much 
 denser than amianthus. It is slightly unctuous to the touch. Specific gravity 2*7. 
 Fuses with difficulty into a greyish-black scoria. It is more abundant than amianthus, 
 and is found usually in serpentine, as at Portsoy in the Isle of Anglesea, and at the 
 Lizard in Cornwall. It was found in the limestone of Glentilt, by Dr. M'Culloch, in a 
 pasty state, but soon hardened by exposure to air. 
 
 Mountain Leather consists, not of parallel fibres like the preceding, but inter- 
 woven and interlaced so as to become tough. When in very thin pieces, it is called 
 mountain paper. Its colour is yellowish-white, and its touch meagre. It is found at 
 Wanlockhead, in Lanarkshire. Its specific gravity is uncertain. 
 
 Mountain Cork, or Elastic Asbestos, is, like the preceding, of an interlaced fibrous 
 texture ; opaque ; has a meagre feel and appearance, not unlike common cork, and 
 like that substance is somewhat elastic. It floats on water. Its colours are, white, grey, 
 and yellowish-brown. It takes an impression from the nail ; is very tough ; cracks when 
 handled, and melts with difficulty before the blowpipe. Specific gravity from 0'68 
 to 0-99. 
 
 Mountain Wood. Ligniform asbestos is usually massive, of a brown colour, and 
 has the aspect of wood. Internal lustre glimmering. Soft, sectile, and tough ; opaque ; 
 feels meagre ; melts to a black slag. Specific gravity 2-0. It is found in the Tyrol ; 
 Dauphiny ; and in Scotland, at Glentilt, Portsoy, and Kildrumie. 
 
 The ancients manufactured cloth out of the fibres of flexible asbestos, for the pur- 
 pose, it is supposed, of wrapping up the bodies of the dead when exposed on the 
 funeral pile. This cloth has also been made in modern times, the chief artifice 
 seeming to consist in the admixture of flax and a liberal use of oil, both which 
 substances are afterwards consumed by exposing the cloth for a certain time to a 
 rod heat. Gloves are made of it for holding red-hot crucibles, &c. The cloth of 
 asbestos, _ when soiled, is restored to its primitive whiteness by heating in the fire. 
 Ignition impairs the flexibility of asbestos in a slight degree. U. 
 
 ASBOX.AKT. See COBALT, EABTHY. 
 
 ASBOX.Z10-E. A nitrogenous substance contained, according to Bra con not (Ann 
 Ch. Phys. [2] xxxi. 37), in soot. (&roArj). It is extracted by boiling the soot with 
 water, evaporating, redissolving in water, adding hydrochloric acid to the solution 
 washing the pitchy precipitate with cold water, then boiling it with water, filtering 
 after cooling, evaporating again, and treating with boiling water till no deposit forms 
 on cooling. The liquid then yields by evaporation a kind of varnish, partially soluble 
 
416 ASCLEPIADIN ASH. 
 
 in alcohol ; and on treating the residue with ether and evaporating, asboline remains in 
 the form of a yellow, very acrid, bitter, volatile oil, which is lighter than water, burns 
 with flame, and yields an ammoniacal product by distillation. Asboline dissolves in 
 nitric acid, yielding picric and oxalic acids. Its aqueous solution is coloured deep red 
 by alkalis, forms an orange-coloured precipitate with acetate of lead, reduces nitrate of 
 silver, and is precipitated by infusion of galls. 
 
 ASCXiSPZADIW. A bitter emetic principle, contained in the Asdepias vince- 
 toxicum. It is insoluble in water, alcohol, and alcoholic ether. It appears not to 
 contain nitrogen. (Fenelle, J. Pharm. [2] xi. 565.) 
 
 ASCZiEPIOKTE. C 20 H 34 S . When the white milky juice of Asdepias syriaca is 
 heated, the albumin contained in it coagulates, and on treating the coagulum with 
 ether, and evaporating, asclepione is deposited in finely radiated or cauliflower-like 
 groups of crystals. It is tasteless, inodorous, quite insoluble in water and alcohol, but 
 dissolves readily in ether, less easily in oil of turpentine, naphtha, and strong acetic 
 acid. It melts at 104 C., and then remains amorphous. At a higher temperature, it 
 decomposes, giving off the odour of burnt caoiitchouc. It is not attacked by strong 
 bailing potash. (List, Ann. Ch. Pharm. Ixix. 125.) 
 
 ASH OP ORGANIC BODIES. When any part of an organised body, 
 vegetable or animal, is burnt with free access of air, part of it is resolved into volatile 
 compounds, chiefly water, carbonic anhydride, and free nitrogen, while the other, and 
 generally the smaller portion, is left as incombustible residue or ash. This residue 
 may contain the following elements : 
 
 Basic. Acid. 
 
 Potassium Chlorine 
 
 Sodium, Bromine 
 
 Calcium Iodine 
 
 Barium Phosphorus (as phosphoric acid) 
 
 Iron Sulphur (chiefly as sulphuric acid) 
 
 Magnesium Silicon (as silicic acid) 
 
 Manganese Carbon (as carbonic acid, and occa- 
 Aluminium sionally as cyanogen). 
 
 Copper 
 Zinc 
 (Lead, nickel, cobalt, tin) ? 
 
 These substances are the so-called inorganic or mineral constituents of the vege- 
 table or animal structure ; they are essential to its existence, and are associated with 
 the organic matter in certain definite forms, not necessarily the same as those which 
 they assume in the ash. It must be remembered, however, that the distinction 
 between the organic and inorganic elements of an organised body is by no means 
 absolute : for the carbon and oxygen, which are never absent from the ash, belong 
 essentially to the organic structure of the body. Perhaps the best distinction between 
 the organic and inorganic constituents of a plant or animal body is, that the former, 
 viz. the carbon, hydrogen, oxygen, and nitrogen, are derived, in great part at least, 
 from the air, whereas the latter are derived exclusively from the soil. 
 
 The inorganic constituents above enumerated are not all of equal importance to the 
 existence of organised structures, or of equally frequent occurrence. Potassium, 
 sodium, calcium, magnesium, and iron, associated with phosphoric acid, sulphuric acid, 
 carbonic acid, silicic acid, and chlorine, are almost always present, in greater or 
 lesser quantity, in the ashes of organised bodies, whether vegetable or animal ; 
 fluoride of calcium, in very small quantity, appears also to be an almost invariable con- 
 stituent ; and manganese, also in small quantity, is of frequent occurrence ; the other 
 elements are of rare or doubtful occurrence. 
 
 The mineral constituents of plants and animals vary greatly in amount, as well as 
 in composition. In bone, the inorganic matter constitutes from to f of the entire 
 mass, the amount in individual cases depending upon the age and species of the 
 animal ; in the higher classes of animals, the bone-ash consists mainly of p h o s p h a t e 
 of calcium, with a smaller quantity of carbonate ; in the lower classes, the propor- 
 tions of these constituents are reversed. Phosphate of calcium occurs also in the 
 ashes of the albuminous principles, both of plants and animals, and is especially abun- 
 dant in the seeds of cereal and leguminous plants; phosphate of magnesium 
 is abundant in the ash of wheat-grain. The alkali nee hi orides are very 
 widely diffused throughout the bodies of plants and animals; chloride of sodium 
 is invariably present in the fluids of the animal body and in the juices of plants. 
 Alkaline carbonates are always present in the blood, and appear to be essential 
 to the solution of the albuminous principles. Carbonate of potassium forms the 
 
ASH OF ORGANIC BODIES. 417 
 
 greater part of wood-ash. Silica is scarcely ever absent from the ashes of organised 
 bodies. The ashes of equisetaccous plants contain 97 per cent, of silica. The hard 
 external sheathing of the stems of grasses consists of silicate of potassium. The 
 shields of the lowest classes of animals, infusoria, &c., consist mainly of silica, which 
 is so thickly deposited in their organs, that neither decomposition nor incineration can 
 destroy their form : hence it is that deposits of infusoria are so often discovered. In 
 the tissues and juices of the higher classes of animals, silica occurs only as an inci- 
 dental constituent, though it is seldom altogether absent. According to Grorup- 
 Besanez (Ann. Ch.Pharm. Ixvi. 342), it forms an integral constituent of feathers and 
 of hair. 
 
 Sulphur occurs to the amount of about 1 per cent, in all the albuminoi'dal sub- 
 stances, and is converted during incineration into sulphuric acid, which is found in 
 the ash as alkaline sulphate, sometimes however more or less reduced to sulphide by 
 the action of the carbon at a high temperature. The juices of the animal body and of 
 plants also contain small quantities of alkaline sulphates and sulphate of calcium. 
 
 Iron is always present in vegetable and animal tissues and fluids, and is found in 
 the ash as sesquioxide, either free or as basic phosphate. 
 
 Alumina has been found in considerable quantity in the juice of plants which ex- 
 hibit an acid reaction, e.g. in Lycopodium chamacyparissus, L. clavatum, and L. den-, 
 ticulatum (Salm-Horstmar, J. pr. Chem. xl. 302; Aderholdt, Ann. Ch. Pharm. 
 Ixxxii. Ill; Solms-Laubach, ibid. c. 297). In most other plants, alumina is alto- 
 gether absent, any small quantities that may be found in the ash, generally arising 
 from impurity in the reagents, especially in the caustic potash or soda, or from want 
 of due care in cleansing the leaves, roots, or other parts under examination, from 
 adhering particles of soil. 
 
 The other metals above-mentioned as occasional constituents of ashes, occur only 
 in very small quantity, their presence being mostly, perhaps, due to some peculiarity 
 in the nutrition of the plant or animal in which they are found. A peculiar kind of 
 violet (Viola calaminaris] with yellow flowers, was found by A. Braun (Pogg. Ann. 
 xcii. 175) to contain zinc, which metal was likewise found in the soil, its presence 
 doubtless determining the production of the peculiar variety of the plant. The ash of 
 the blue blood of Limulus cyclops was found by Genth (Pogg. Ann. xcv. 60) to contain 
 0'08 to 0'33 per cent, of oxide of copper. The occurrence of titanic acid in 
 plant-ashes is mentioned by Stadeler (Wohler's prakt. Chem. Uebungen, 1853 
 p. 173), of baryta by Scheele (in 1788), and more recently by Eckard (Ann. Ch. 
 Pharm. c. 294), and by Forchhammer (Pogg. Ann. xcv. 60; Jahresber d. Chem. 
 1859, p. 987). On the occurrence of copper and other metals in plant-ashes, see also 
 Jahresber. 18478, p. 874 ; 1849, p. 430 ; 1852, p. 702 ; 1853, p. 604. 
 
 As the mineral constituents of plants are all derived from the soil and vary greatly 
 both in amount and in composition, it will be easily understood that the examina- 
 tion of plant-ashes is of great importance with reference to agriculture. A plant will 
 not grow on soil deficient in the mineral substances which it requires ; if phos- 
 phoric acid is deficient, wheat and other cereal grasses cannot form their seed in its 
 normal amount ; if there is a deficiency of silica, the straw will be weak. Some 
 plants require abundance of alkali, others of lime, &c. The examination of the ash 
 shows what particular mineral substances the plant requires, and consequently what 
 substances must be supplied to it artificially in the form of manure, if they are not 
 already contained in the soil. 
 
 We now proceed to describe the preparation and analysis of ashes. 
 
 Preparation of the Ash. The substance to be incinerated must in the first 
 place be carefully freed from extraneous matter. Herbs, roots, and barks, which are 
 especially liable to be contaminated with adhering mould, clay, or sand, must first 
 be cleaned from the grosser impurities by scraping, or otherwise, and then washed 
 with a slightly moistened sponge to remove the fine dust; washing with large quanti- 
 ties of water is objectionable, as it may remove some of the soluble salts. Seeds are 
 best cleaned by pouring distilled water upon them in a glass jar, stirring for a little 
 while with a rod, and then pouring the whole on a coarse sieve, which allows the fine 
 dust to run through, but retains the seeds. After repeating this treatment two or three 
 times, the seeds may be further cleansed by rubbing them between a linen cloth. 
 Animal substances are less liable to contamination with mechanical impurities ; 
 their incineration is often facilitated by exhausting them with water, and incinerat- 
 ing separately the aqueous extract and the residue. The quantity of material 
 incinerated should be such as to yield from 4 to 6 grammes of ash. Of seeds, roots, barks, 
 and leaves, which are for the most part rich in mineral constituents, from 100 to 200 
 grammes of the dried substance is generally sufficient ; of wood, two or three times 
 that quantity must be taken ; of animal substances containing a large amount of 
 
 VOL. I. E E 
 
418 ASH OF ORGANIC BODIES. 
 
 water, it is often necessary to incinerate a much larger quantity. The substance should, 
 previous to incineration, be carefully dried and somewhat comminuted; seeds, however, 
 if not very large, are best incinerated without comminution. 
 
 The incineration must be conducted with great care, as the constitution of the ash 
 is often materially affected by the manner in which it is performed. The chlorides of 
 potassium and sodium, though fixed at comparatively low degrees of heat, volatilise per- 
 ceptibly at the high temperature sometimes attained during the incineration, especially 
 in a current of air ; this is still further the case with iodides. Moreover, by the joint 
 action of silica and charcoal, phosphates may be decomposed and phosphorus volati- 
 lised; sulphates also reduced to sulphides, or sulphuric acid driven off. And even 
 when no actual loss takes place, different modes of incineration may give rise to con- 
 siderable differences in the composition of the ash. Carbonates in an ash generally 
 result from the combustion of salts of organic acids existing in the substance burned ; 
 they may, however, be introduced in other ways. If tribasic phosphate of sodium be 
 ignited in presence of a large quantity of organic matter, sugar, for example, till the 
 organic matter is charred, and the mass be then lixiviated with water, a solution of 
 carbonate of sodium is obtained, and the residue, after the charcoal has been com- 
 pletely burned away, consists of pyrophosphate of sodium, the carbonic acid produced 
 by the combustion of the organic matter having decomposed the tribasic phosphate, 
 taken away 1 at. of the base, and converted it into carbonate. If, on the other 
 hand, the mass be at once completely incinerated without lixiviation of the charcoal, 
 nothing but tribasic phosphate will be obtained. In all cases then, in which the 
 arrangement of the mineral constituents of an organised structure is to be inferred from 
 the composition of the ash, great care must be taken to guard against or allow for any 
 such modifications as that just noticed. In the examination of plant-ashes for agri- 
 cultural purposes, such questions are indeed of minor importance, the chief object of 
 the investigation being to determine the ultimate constituents of the ash ; but in 
 physiological inquiries, the actual arrangement of the mineral constituents in the living 
 structure is often a point of great importance. 
 
 The difficulty of incinerating an organic substance is greatly increased when the ash 
 is easily fusible, the decompositions just considered being then most likely to occur. 
 Leaves, herbaceous stems, roots, bark, &c., which chiefly contain infusible salts of the 
 alkaline earths, are comparatively easy to burn; but seeds, and many animal sub- 
 stances, such as dried blood, which contain large quantities of alkaline salts, are very 
 troublesome, and require great care in regulating the temperature. 
 
 The method of incineration originally "practised, especially for the preparation of 
 plant-ashes, consisted in burning the dried substance in a Cornish or Hessian crucible, 
 laid obliquely in the fire, and kept at a moderate red heat. The carbon then burns 
 away with greater facility, the looser the texture of the charred mass, and the less its 
 position and form are altered by movement and stirring. The objections to this 
 method are that it often gives incorrect results regarding the amount of phosphoric 
 acid, carbonic acid, and chlorine, inasmuch as chlorides are decomposed by the action 
 of acid phosphates in presence of water, and at very high temperatures, phosphorus may 
 be volatilised by the action of charcoal on acid phosphates. Extraneous matters may 
 also be introduced into the ash by the action of phosphates in a state of fusion on the 
 crucible. 
 
 A much better method is that recommended by Erdmann, which consists in in- 
 cinerating the plant or animal substance in a muffle built into the mouth of a fur- 
 nace in such a manner that the heat may play upon it chiefly from the top. 
 The incineration goes on most favourably at a distance of 3 or 4 inches from the 
 front aperture of the muffle, and at a low red heat not visible by daylight. At 
 this temperature, there is no danger either of the volatilisation of chlorides or of the 
 fusion of phosphates. If the muffle be kept loosely closed by a clay stopper, sufficient 
 air will enter fco produce, in the course of twelve hours, a quantity of ash free from 
 charcoal sufficient for an analysis. A convenient mode of proceeding is first to char 
 the substance in a platinum or porcelain dish, and then heat the charred residue in 
 the muffle in the manner just described ; the charcoal then burns away with slight 
 incandescence. The ash may afterwards be weighed in the dish. 
 
 Messrs. Lawes and Gilbert use cast-iron muffles 18 inches long, 3| inches high, 
 and 5 inches wide at the bottom. The muffle, which has a flange at the fore part, 
 fits exactly into an orifice in a cast-iron furnace front ; and a 1| inch pipe proceeding 
 from the farther end of the muffle, passes through the cast iron furnace back, and 
 serves to carry away the evolved gases. The muffle rests on a brick in the furnace, to 
 lessen bottom heat and thus prevent fusion, the fuel being heaped up at the. sides and 
 top, chiefly the latter. The substance is burnt in large platinum sheets or dishes, the- 
 latter 10 inches long, 4 to 5 inches wide, and 1| inch deep. By this arrangement, tho 
 access of ash from the fire is entirely avoided ; the ash is burnt by surface, not by 
 
ASH OF ORGANIC BODIES. 419 
 
 bottom heat ; the draught of air is free ; and the incineration may be accomplished at 
 a very low temperature.* 
 
 This is by far the best mode of incineration yet devised ; nevertheless it is occa- 
 sionally attended with slight loss of sulphur, phosphorus, chlorine, iodine, &c. To ob- 
 viate these losses, it has been proposed to mix the substance to be incinerated with lime, 
 baryta, or other strong bases capable of retaining the acids. Wackenroder adds for 
 this purpose, acetate or carbonate of calcium, or quick lime; Streaker proposes to 
 moisten the dried and charred substance with such a quantity of baryta- water, that the 
 ash, after incineration, may contain about half its weight of baryta. The moistened 
 charcoal is then dried and burnt in the muffle at as low a temperature as possible. To 
 substances which produce ashes containing much carbonic and silicic acids, Way and 
 O g s t o n , add for the same purpose, nitrate of barium ; Slater adds peroxide of barium ; 
 Verdeil, nitrate of ammonium; and Will, mercuric oxide; but all these admixtures 
 are attended with peculiar inconveniences, which stand in the way of their general 
 application. 
 
 H. Rose adds a weighed quantity of carbonate of sodium, chars the substance in a 
 crucible, and burns away the charcoal by directing a stream of oxygen upon it through 
 an aperture in the lid. This method effects a complete and rapid combustion of the 
 charcoal, but the high temperature produced often causes the ash to fuse, and then the 
 crucible is attacked. Crucibles of stone- ware (Steinguf) withstand the action better 
 than those of porcelain. 
 
 [For the methods of Mitscherlich and Hlasiwetz, seeHandw. d. Chem. 2 to Aufl. 
 ii. 352 ; for the latter also, Ann, Ch. Pharm. xcvii. 244.] 
 
 Analysis of the Ash. Of the various methods which have been given for the 
 analysis of ashes, the simplest and most generally applicable is that of Professor 
 Will (Handw. d. Chem. 2 te Aufl. ii. 361 ; Conington's Handbook of Chemical Analysis, 
 p. 226). The ash prepared in the muffle at the lowest possible temperature, is tritu- 
 rated to a uniform powder, and preserved in a stoppered bottle. One portion of it is 
 used to determine the carbonic acid by one of the methods given under ALKALIMETRY, 
 p. 119. A second is treated with dilute nitric acid, and the filtrate is used for deter- 
 mining the chlorine by precipitation with nitrate of silver ; while a third portion (4 or 5 
 grammes) is used for determining the silica and the other constituents. For this last 
 purpose, the ash is treated with hydrochloric, acid ; the silica separated by complete 
 evaporation to dryness, and digestion of the residue with water containing hydro- 
 chloric acid (see SILICA); and the quantity of the filtrate, together with the washings, is 
 determined, either by weight or by measure. 
 
 In one portion of this filtrate, of known weight or volume, the sulphuric acid is 
 determined by precipitation with chloride of barium ; in a second, the lime, magnesia, 
 sesquioxide of iron (alumina, if present), and the phosphoric acid; in a third, the 
 alkalis. 
 
 Lime, Magnesia, Ferric Oxide, Phosphoric Acid. If, as in the ashes of seeds and of 
 many animal substances, all the bases, or the greater part of them, are present as 
 phosphates, the liquid is first supersaturated with ammonia (or mixed with acetate of 
 sodium), then with acetic acid, and the undissolved ferric phosphate, Fe 4 3 .cP 2 5 , is 
 collected and weighed (together with phosphate of aluminium, if present, which may 
 afterwards be separated by potash). The lime is next precipitated by oxalic acid, 
 then part of the phosphoric acid and all the magnesia by ammonia, and the rest of the 
 phosphoric acid by a magnesium-salt. In ashes containing a smaller proportion of 
 phosphoric acid, part or the whole of the magnesia remains in solution after this treat- 
 ment. This portion is determined by precipitation with phosphate of sodium, or (if 
 the filtrate is to be afterwards used for the determination of the alkalis) with phosphate 
 of ammonium. If manganese is likewise present (as a manganous salt), the ferric 
 phosphate is first precipitated as above ; the liquid filtered from the precipitate is 
 mixed with a known volume of a standard solution of ferric chloride made as neutral 
 as possible ; the whole is heated to boiling ; the precipitate thoroughly washed with 
 hot water and dried ; and from its weight, that of the (anhydrous) phosphoric acid is 
 found by deducting the weight of the ferric oxide added t ; to this quantity of phos- 
 phoric acid, must be added that which was previously determined as ferric phosphate 
 (and phosphate of aluminum). In the filtrate, which contains manganese, calcium, 
 and magnesium, these metals are determined by the usual methods, the manganese 
 being precipitated as peroxide by hypochlorite of sodium, the precipitate collected after 
 twenty-four hours, then ignited or weighed as manganoso-manganic oxide (Mn 3 2 ). 
 
 Alkalis. The ash, dissolved in hydrochloric acid, not in great excess, is mixed with 
 
 * For the above description, the Editor is indebted to the kindness of Dr. Gilbert. 
 
 t The amount of phosphoric acid in this precipitate might be determined directly by dissolving in 
 hydrochloric acid, adding sufficient tartaric acid to prevent precipitation of iron and alumina by alkali-, 
 then adding excess of ammonia, and precipitating by a magnesium-salt. 
 
 E E 2 
 
420 ASH; VOLCANIC. 
 
 oxalic acid, then with excess of ammonia, and if magnesia is Btill in solution, with 
 phosphate of ammonium.* The precipitate is washed with ammoniacal water; th^ 
 filtrate is evaporated a little to expel the excess of ammonia, and mixed while still 
 hot with acetate of lead ; the liquid is again filtered, and the excess of lead removed 
 by ammonia and carbonate of ammonium ; the filtrate from this precipitate, together 
 with wash-water, is evaporated, with addition of sal-ammoniac ; and the ammoniacal 
 salts are expelled by gentle ignition. The residue, which contains nothing but the 
 chlorides of potassium and sodium, is then weighed, and the relative quantities of the 
 two chlorides are determined, either by precipitating the potassium with dichloride of 
 platinum, or determining the amount of chlorine by precipitation with nitrate of 
 silver. (See ANALYSIS, INDIRECT, p. 220.) 
 
 Knop and Arendt (Chem. Centralbl. 1857, 169), determine the phosphoric acid in 
 ashes by adding uranic acetate to the solution, acidulated with acetic acid as above, 
 whereby a precipitate of ammonio-uranic phosphate is produced, which, when ignited 
 with addition of a few drops of nitric acid, leaves uranic phosphate, containing 
 2Ur 4 3 .P 2 5 . (For the details of the method, see PHOSPHORIC ACID, under PHOS- 
 PHORUS.) 
 
 For other methods of ash-analysis, see Fresenius and Will, Ann. Ch. Pharm. 1. 
 363; Erdmann, J. pr. Chem, xxxviii. 20; H.Rose, Pogg. Ann. Ixxx. 94, and 
 Handb. d. Analyt. Chem. ii. 766 ; Mitscherlich, J. pr. Chem. xxxv. 231 ; Wacken- 
 roder, Arch. Pharm. [2] liii. 1 ; Stadeler, Prakt. TJebungen in der Chem. Anal, von 
 Wohler, 1853, 172 ; Wittstein, Pharm. Centralbl. 1853, 761. Also for a description 
 of all these methods, Handw. d. Chem. 2 te Aufl. ii. 353. 
 
 For the composition of the ash of individual plants, see the names of the plants in 
 this dictionary. Extensive tables of the composition of plant-ashes are given in the 
 first five volumes of Liebig and Kopp's Jahresbericht fur Chemie, 1847 to 1852. The 
 new edition of lire's Dictionary of Arts, Manufactures, and Mines (i. 212), also con- 
 tains a table showing the average composition of the ash of some of the most useful 
 agricultural plants. 
 
 ASH, VOLCANIC. This name is applied to the pulverulent portion of the 
 matter thrown out by volcanos. The ash emitted by different volcanos, by the same 
 volcano at different times, and even at different stages of the same eniption, exhibits 
 great differences of structure and composition. It is sometimes dark-coloured or even 
 black, and composed of earthy or soft particles, sometimes grey or white, and finely 
 divided. In the eruption of Vesuvius, A.D. 79, which overwhelmed Pompeii and 
 Herculaneum, the ash was so fine and dry that it took exact casts of objects buried 
 in it. It is this finely divided matter to which the term ash is especially applied, 
 the coarser varieties being generally denominated volcanic sand; it sometimes 
 rises to considerable heights, and is then carried by the wind to great distances. In 
 the eruption of Coseguina, on the Bay of Conchagua, in Guatemala (1835), some of the 
 ash fell at Kingston in Jamaica, at a distance of 700 miles. 
 
 Volcanic ash, when examined by the microscope, appears to be composed of frag- 
 ments of lava, slag, mica, felspar, magnetic iron ore, augite, pumice, olivine, &c. It 
 is therefore a mechanical mixture of minerals and rocks abraded by trituration against 
 each other. In the ash thrown out by Vesuvius on the 22nd of October 1822, 
 Vauquelin found 28 pts. silica, 8'0 alumina, 18 gypsum, 20-88 iron pyrites, 2-6 lime, 
 and 1 carbon, together with 41-42 pts. sulphate of copper, sulphate of ammonium, 
 chlorides, and sulphur. In the ash emitted from the crater of the Soufriere in Guada- 
 loupe, in 1797, Dufrenoy (Ann. Ch. Phys. [2] Ixvii. 251) found 2 per cent, of alum, 
 potash, and gypsum, 8-84 water, 32'61 pts. of matter attacked by acids (which he 
 regarded as labrador), and 56'23 pts. not attacked by acids (regarded as glassy fel- 
 spar). In the ash thrown out by the same crater in the year 1836, Dufrenoy found 
 50-88 pts. of matter insoluble in acids, 33'72 pts. soluble in acids, 6'93 water and 
 0-62 sulphur (loss 1-85 per cent.) 
 
 The following table contains the results of a few more recent analyses : a, b, ash 
 from the above-mentioned eruption of Coseguina (Dufrenoy and Eli e de Beaumont, 
 Ann. Ch. Phys. [2] Ixviii. 266) ; this ash contained 18 pts. of matter decomposable 
 by hydrochloric acid (a), and 82 pts. unattacked by that acid (6). c, Ash from 
 Gunnung-Gurtur, in Java; eruption of January 4th, 1843 (Mayer, Leonhard, and 
 Bronn's Jahrb. d. Miner. 1853, 463). d, Ash from the same volcano ; eruption of 
 November 25th, 1843. Of this ash, water dissolved 0-3 per cent, consisting of lime 
 and magnesia-salts (Schweitzer, J. pr. Chem. Ixv. 194). e. So-called ferric ashes, 
 and/, so-called ferrous ashes from Etna (Sartorius von Waltershausen, "Vul- 
 canishe Gesteine," Gottingen. 1853, 172). q. Ash from the eruption of Hecla in 1846 
 (Genth, ibid. 176). 
 
 For other methods of separating magnesia from the alkalis, see MAGNBSIUII. 
 
ASPARAGINE. 
 
 421 
 
 Silica . 
 Alumina 
 Ferric oxide 
 Ferrous oxide 
 Lime 
 Magnesia 
 
 Potash . 
 Water and loss 
 Matter soluble in water 
 
 a 
 
 b 
 
 e 
 
 d 
 
 e 
 
 / 
 
 9 
 
 517 
 
 64-3 
 
 34-2 
 
 51-6 
 
 487 
 
 51-3 
 
 56-9 
 
 15-2 
 
 21-1 
 
 37'5 
 
 21-9 
 
 17-9 
 
 18-4 
 
 14-2 
 
 13-0 
 
 . 
 
 18-2 
 
 
 
 127 
 
 
 
 
 
 
 
 
 
 67 
 
 10-8 
 
 
 
 117 
 
 13-9 
 
 11-1 
 
 1-4 
 
 07 
 
 9-3 
 
 5-5 
 
 7'5 
 
 6-2 
 
 
 
 07 
 
 
 
 3-3 
 
 2-5 
 
 4-3 
 
 4-0 
 
 6-2 
 
 9-6 
 
 __ 
 
 2-9 
 
 4-5 
 
 4-6 
 
 2-3 
 
 
 
 
 
 
 
 0*5 
 
 2-0 
 
 1-6 
 
 2-6 
 
 2-8 
 
 3-4 
 
 1-0 
 
 0-6 
 
 6-6 
 
 0-5 
 
 __ 
 
 17 
 
 0-3 
 
 27 
 
 100-0 100-5 100-0 101-2 101-4 102'6 lOO'l 
 
 C*H*N 2 8 , ar C S H S N 2 6 : Altheine, Asparamide. (G-m. x. 
 239.) This substance was discovered in 1805 by Vauquelin and Kobiquet (Ann. 
 Chim. Ivii. 88). It exists ready formed in many plants, viz. in common asparagus 
 (Asparagus offieinalis}, in the marsh-mallow (Alihacea off.}, in comfrey (Symphytum 
 off.}, in potatoes, in chestnuts,, in the leaves of the deadly nightshade (Atropa Bella- 
 donna}, in liquorice-root, in the root of Eobinia pseudacacia, in Convallaria majalis, 
 and C. multiflora, in the milky juice of the lettuce, in the tubers of the dahlia, and 
 in the young shoots of vetches, peas, beans, and several other leguminous plants grown 
 in the dark. According to Piria (Ann. Ch. Phys. [3] xxii. 160), the young shoots of 
 these plants, when formed in the light, contain just as much asparagine as when they 
 are grown in the dark ; but the asparagine disappears as the plant arrives at the flower- 
 ing stage. On the other hand, JDessaignes and Chautard (J. Pharm. [3] xiii. 
 245), and likewise Pasteur (Ann. Ch. Phys. [3], Ixxxi. 70), find that vetches growing 
 in light are free feom asparagine. 
 
 Preparation. The juice obtained from the young shoots of asparagus, filtered and 
 evaporated to a syrup, deposits after standing for some days, crystals of asparagine, 
 which may be purified by recrystallisation from water. As the mucus of the plant 
 impedes the crystallisation, it is best to leave the shoots to ferment for a few days in 
 a warm place, and then bruise and press them, with addition of water ; by this treat- 
 ment the mucus is decomposed. In a similar manner, asparagine may be obtained 
 from marsh-mallow roots, and from the young shoots of vetches, &c. grown in the 
 dark. To obtain asparagine from liquorice-root, the root is cut into pieces and ex- 
 hausted with water; the liquid boiled to precipitate the albumin, then mixed with 
 acetic acid to separate the glycyrrhizin contained in the root, and afterwards with 
 acetate of lead, which throws down phosphate and malate of lead, together with brown 
 colouring matter; and the excess of lead is removed by sulphydric acid. The 
 filtered liquid evaporated to a small bulk, deposits crystals of asparagine after a few 
 days. 
 
 Asparagine forms hard brittle crystals, C 4 H fl N 2 O s .H 2 0, belonging to the trimetric 
 system. The ordinary form is a right rhombic prism, ooP . oP . mP oo . oo f* oo, with 
 the hemihedral faces ^-. Inclination of the faces, ooP : o>P = 129 37'; \ : oP = 
 116-57'; mPoo : oP = 120 46'. Specific gravity 1-519 at 14 C. The crystals are 
 inodorous, have but a slight taste, and are permanent in the air. They give off water 
 of crystallisation at 100 C. They dissolve in 11 pts. of cold, and 4-44 pts. of boiling 
 water ; the solution has a slight acid reaction. Asparagine dissolves also in acids and 
 in alkalis. It is insoluble in cold absolute alcohol, and nearly insoluble in that liquid 
 at higher temperatures ; insoluble also in ether and in oils, whether fat or volatile. 
 
 Asparagine dissolved in water and in alkalis, deflects the plane of polarisation of a 
 ray of light to the left ; but when dissolved in acids, it deflects the plane of polarisa- 
 tion to the right. The specific rotatory power of an acid solution is + 35, and of an 
 ammoniacal solution, 11 18'. 
 
 Asparagine heated with strong acids or alkalis, is resolved into aspartic acid and 
 ammonia : 
 
 C 4 HN 8 3 + H 2 = C 4 H 7 N0 4 + NH S . 
 
 The crystals subjected to dry distillation also give off ammonia, and leave aspartic acid. 
 Asparagine dissolved in cold nitric acid, yields aspartic acid and nitrate of ammonium, 
 but when subjected to the action of nitrous acid, as when nitric oxide gas is passed 
 through a solution of asparagine in pure and moderately strong nitric acid, it is con- 
 verted into malic acid, with evolution of nitrogen : 
 
 C 4 H 8 N 2 3 + N 8 3 
 
 CH0 S 
 E 3 
 
 H 2 
 
422 
 
 ASPARAGINE ASPARTIC ACID. 
 
 The solution of pure asparagme-crystals may be kept unaltered ; but if the crystals 
 are coloured, their solution soon passes into a state of fermentation, and the whole of 
 the asparagine is converted into succinate of ammonium : 
 
 C 4 H 8 N 2 3 + H 2 + H 2 = C 4 H 4 (NH 4 ) 2 4 . 
 
 The hydrogen is derived from the fermenting matter. A solution of perfectly pure 
 asparagine experiences the same change when mixed with a small quantity of the 
 juice expressed from the young shoots of vetches (Piria). Asparagine ferments also 
 under the influence of casein, and is converted first into aspartate of ammonium, after- 
 wards into succinate. 
 
 Asparagiue forms definite compounds with acids. The hydrochlorate, C 4 H 8 N 2 3 .HC1, 
 is obtained in large crystals either by dissolving 1 at. asparagine in 1 at. hydrochloric 
 acid, evaporating at a gentle heat, and adding alcohol ; or by passing dry hydrochloric 
 acid gas over finely pounded crystals of asparagine, exposing the resulting compound 
 to the air till it no longer gives off acid vapours, then dissolving in hot water, and 
 leaving the solution to cool. 
 
 Asparagine also forms salts in which 1 at. of its hydrogen is replaced by a metal ; 
 thus the copper-salt is C 4 H 7 CuN 2 3 . These salts are obtained by mixing a solution of 
 asparagine with the corresponding oxides. Asparagine also unites with chloride of 
 mercury and nitrate of silver. 
 
 Asparagine has the same composition as malamide, N 2 (H 4 .C 4 H 4 3 }, and its conversion 
 into malic acid by the action of nitrous acid, suggests the idea that it may be really 
 the amide of that acid. According to Demondesir, however (Compt. rend, xxxiii. 
 227), and Pasteur (Ann. Ch. Phys. [3] xxxviii. 437) the amide obtained by the 
 action of ammonia on malic ether, differs from asparagine in crystalline form and in 
 other properties. 
 
 ASPARAGOXiXTC. An old name of the variety of apatite which has the green 
 colour of asparagus. 
 
 ASPARAGUS OFFXCXBTAIiXS. The ashes of wild and cultivated asparagus, 
 and of the young heads of the cultivated plant, have been analysed by T. J. Hera- 
 path (Chem. Soc. Qu. J. ii. 9). 100 parts of the fresh wild plant yielded 2-42 pts. of 
 ash; 100 pts. of same dried, 6-07 per cent. ash. The cultivated plant yielded in the 
 fresh state 1-53, and in the dry state 6*07 per cent. ash. The young heads in a state 
 fit for the table gave 0*81 per cent, and 11 -24 per cent. ash. The constituents of 
 the several ashes are as follows : 
 
 Soluble in water: 
 ^ ( Carbonic acid 
 "0 < Sulphuric acid 
 <' (Phosphoric acid . , 
 
 Potash 
 
 Soda 
 
 Chloride of sodium 
 
 Chloride of potassium , 
 Insoluble: 
 
 Carbonate of calcium 
 
 Carbonate of magnesium 
 
 Basic c-phosphate of calcium . 
 
 Basic ferric c-phosphate . 
 
 Silica 
 
 Sulphate of calcium 
 
 Basic phosphate of magnesium 
 
 Wild. 
 
 4-86 
 
 7-77 
 trace 
 15-81 
 
 2-72 
 20-51 
 
 21-43 
 2-62 
 
 21-67 
 1-70 
 0-85 
 trace 
 trace 
 
 99-94 
 
 Soluble in water (per cent.) . 51-67 
 Insoluble . 48'27 
 
 Cultivated. 
 
 Young Heads. 
 
 14-27 
 
 4-01 
 
 3-56) 
 2-loJ 
 
 31-08 
 
 32-74) 
 
 32-63 
 
 $ 
 
 
 trace ) 
 13-06$ 
 
 10-06 
 
 14-61 
 
 6-96 
 
 16-21 
 
 14-05 
 
 0-46 
 
 0-21 
 
 2-97 
 
 1-00 
 
 trace 
 
 trace 
 
 trace 
 
 trace 
 
 99-98 
 
 57-64 
 42-34 
 
 100-00 
 
 778 
 22-22 
 
 ASPARAIVIIDE. Syn. with ASPARAGINE. 
 
 ASPARAXVXXC ACID. Syn. with ASPABTIC ACID. 
 
 ASPARTXC ACXX>. C*H 7 N0 4 , or WH^NO*. (PI is son, Ann. Ch. Phys. xxxv. 175, 
 
 xl. 303. PlissonandO. Henry, Md.yilv, 315. Boutron-ChautardandPelouzo, 
 ibid. Hi. 90. Liebig, Pogg. xxxi. 232, Ann. Ch. Phann. xxvi. 125, 161. Piria, 
 Ann. Ch. Phys. [3] xxii. 160. Dessaignes, Compt. rend. xxx. 329; xxxi. 342; 
 Ann. Ch. Pharm. Ixxxiii. 83. Pasteur, Ann. Ch. Phys. [3] xxxiv. 30; Ann. Ch. 
 
ASPARTIC ACID. 423 
 
 Pharm. btxxii. 324. Gm. x. 230 ; Gerh. i. 812.) This acid, which is isomeric, if not 
 identical with malamic acid, J g^ \ is obtained either by the decomposi- 
 
 tion of asparagine, chiefly under the influence of acids or alkalis, or by the action of 
 heat on the acid malate, maleate, or fumarate of ammonium. The acids obtained by 
 these two processes are identical in composition, but differ in their relations to pola- 
 rised light,- the former being optically active, the latter inactive. 
 
 To prepare active aspartic acid, asparagine is boiled : 1. With water and oxide 
 of lead, as long as ammonia continues to escape, the water being replaced as it 
 evaporates : the resulting aspartate of lead, after being purified by boiling with 
 water and alcohol, is decomposed by sulphydric acid, and the filtered solution is 
 evaporated till it crystallises (PI is son). 2. With baryta- water, the aspartate of 
 barium being decomposed by sulphuric acid (Boutron and Pelouze). 3. With potash, 
 the liquid being afterwards evaporated to dryness with excess of hydrochloric acid, and 
 the chloride of potassium dissolved out by water, which leaves the aspartic acid undis- 
 solved and perfectly free from potash (Lie big). 4. With hydrochloric acid, for three 
 hours, the solution being then evaporated to dryness, and the residual chloride of 
 ammonium and hydochlorate of aspartic acid dissolved in a small quantity of water 
 and half neutralised with ammonia ; the liquid on cooling deposits a considerable 
 quantity of aspartic acid. (De s s aignes.) 
 
 Active aspartic acid crystallises in very small thin, shining, rectangular plates, trun- 
 cated at the angles ; they belong to the trimetric system. Specific gravity 1*6613 
 at 12'5 C. It is much less soluble in water than asparagine, 1 pt. of it re- 
 quiring 364 pts. of cold water to dissolve it. In boiling water it dissolves more 
 readily, but is nearly insoluble in alcohol. It dissolves readily in alkalis, and the 
 solutions turn the plane of polarisation of a luminous ray to the left. It is also easily- 
 soluble in the stronger acids, and the solutions thus formed turn the plane of polari- 
 sation to the right. The specific rotatory power of the solution in hydrochloric acid 
 is + 27 86'. (Pasteur.) 
 
 Inactive Aspartic Acid is obtained by heating acid malate of ammonium to 
 200 C.; boiling the residue for some hours with hydrochloric acid ; dissolving the hydro- 
 chlorate of aspartic acid, which crystallises from the liquid on cooling, in hot water, and 
 half saturating the solution with ammonia. Inactive aspartic acid then separates in 
 small crystals, belonging to the monoclinic system. Ordinary combination coP . o P. 
 [P oo]. Inclination of the faces, o>P : ooP in the plane of the oblique diagonal and 
 the principal axis = 128 28'; oP : ooP = 91 30'; [Poo ] : oP = 131 25'. The crystals 
 are grouped in stars, and sometimes take a lenticular form. Specific gravity 1-6632 at 
 12' 5 C. The inactive acid is more soluble in water than the active acid, 1 part of it 
 dissolving in 208 pts. of water at 13'5 C. It dissolves very easily in hydrochloric 
 and in nitric acid. The solutions have no action on polarised light. (Dessaignes, 
 Pasteur.) 
 
 Aspartic acid is decomposed by heat, giving off ammonia and a faint empyreumatic 
 odour, like that evolved in the destructive distillation of animal substances. It is not 
 acted upon by boiling with hydrochloric acid or with dilute sulphuric acid, but when 
 heated with strong sulphuric acid, it decomposes, and sulphurous acid is given off. It is 
 not decomposed by pure nitric acid, but if nitrous acid is also present, as when nitric 
 oxide gas is passed through a solution of aspartic acid or nitric acid, the aspartic acid 
 is converted into malic acid, with evolution of nitrogen gas : 
 
 2C 4 H 7 N0 4 + N 2 3 = 2C 4 H 6 5 + N 4 + H 2 
 
 Aspartic Malic 
 
 acid. acid. 
 
 Compounds of Aspartic Acid with Acids. Both the active and inactive varieties of 
 aspartic acid dissolve in the stronger acids, forming definite compounds, which by 
 evaporation over the water-bath, or better by spontaneous evaporation, are obtained in 
 crystals. The compounds are active or inactive to polarised light, according as they 
 are obtained from the active or inactive acid. 
 
 The active hydrochloratc, C 4 N 7 N0 4 .C1H, forms crystals belonging to the trimetric 
 system; they are prisms with angles of aboiit 90, very much truncated on two 
 opposite lateral edges, and terminated by faces inclined at an angle of about 115, and 
 belonging to an iiTegular tetrahedron. The crystals deliquesce in the -air, the aspartic 
 acid being set free. They are decomposed by solution in water, but the addition of a 
 few drops of hydrochloric acid prevents the decomposition. Specific rotatory power 
 of the solution + 24-4. The crystals are decomposed by heat, giving off water and 
 hydrochloric acid, and leaving fumarimide. The crystals of the inactive hydrochlo- 
 ratc belong to tlu i monocHiuc system, and differ altogether in appearance from those 
 
424 ASPARTIC ACID. 
 
 of the active compound. Ordinary combination oo P. ooPoo . P. oP. +mPoo. 
 Inclination of the faces oP : ooP oo = 119 45' ; * P oo : oo P =. 123. The crystals 
 are nearly unalterable in the air, only in summer losing their lustre and transparency, 
 and becoming milk-white on the surface. They decompose when dissolved in water, 
 but the inactive acid being more soluble than the active acid, is not precipitated ; if, 
 however, alcohol be added, an abundant precipitation takes place. The inactive hy- 
 drochlorate is decomposed by heat like the active salt. 
 
 The sulphate, C 4 H 7 NO*.S0 4 H 2 , is obtained by gradually adding aspartic acid to strong 
 sulphuric acid heated to 50 or 60 C. in a wide glass tube, and leaving the tube closed 
 for a few days ; it then separates in large agglomerated prisms, which are lighter than 
 the mother-liquor (Dessaignes). The nitrate is obtained, like the hydrochlorate, in 
 beautiful crystals. 
 
 ASPARTATES. Aspartic acid is monobasic, the formula of its normal salts being 
 C 4 H 6 MNO 4 . It likewise forms basic salts, the composition of which is not very clearly 
 made out. The aspartates of the alkali-metals are soluble, and taste like broth. The 
 active and inactive aspartates agree in composition, and in most of their properties, 
 differing only in solubility, crystalline form, and relation to polarised light. 
 
 The ammonium and potassium salts are very soluble and difficult to crystallise. 
 
 The sodium-salts, C 4 H 7 NaN0 4 .H 2 O, are obtained by neutralising the acid with 
 caustic soda or its carbonate, and leaving the solutions to evaporate slowly; they 
 are perfectly neutral. The active salt crystallises in prismatic needles belonging to 
 the right prismatic system, and terminated by faces of a tetrahedron inclined to one 
 another at about 106. The four faces of this tetrahedron are either present alone, or 
 are much more developed than those of the opposite tetrahedron, which, if equally 
 developed with the former, would constitute a rhombic pyramid ; 1 part of this salt 
 dissolves in 1/12 pts. of water at 12'2 C. The specific rotatory power of the solution 
 is 2 23'. The salt gives off its water of crystallisation at 160 C., turns yellow and 
 gives off ammonia at 170, and froths up considerably at higher temperatures. The 
 inactive sodium-salt crystallises in the monoclinic system, the ordinary combina- 
 tion being oo P . oo P oo . oP . + P. Inclination of the faces, oP : oo P oo a 144 46' ; 
 ooP : ooP, in the plane and of the oblique diagonal and principal axis = 51 38'; 
 + P : + P = 112 53'. The salt often form's twin-crystals, with the face of junc- 
 tion oo P oo. One pt. of the salt dissolves in 1-19 pts. of water at 12-5 C. 
 
 Normal barium-salt, C 4 H 6 BaN0 4 .2H 2 0. The active salt crystallises in very slender 
 silky needles soluble in water, and giving off 14-4 per cent, water at 120 C. (Des- 
 saignes). The inactive normal salt forms an uncrystallisable gummy mass (Wolff). 
 The basic barium-salt is obtained by gradually adding hydrate of barium to a hot and 
 rather strong solution of the normal salt. The liquid solidifies on cooling in a crystal- 
 line mass, but by recrystallisation from boiling water in a vessel protected from the 
 carbonic acid of the air, this salt may be obtained in rather large shining prisms con- 
 taining 2C 4 H 6 BaN0 4 .Ba 2 + 5H 2 0. In vacuo, the crystals give off 3 at. water; when 
 heated to 160 C. they lose 16'4 per cent., and the residual salt contains, according to 
 Dessaignes, 57'Q5 per cent. Ba 2 O, agreeing nearly with the formula C 4 H 5 Ba 2 NO 4 , 
 which requires 57 '55 per cent. This is the formula of the normal salt of a dibasic 
 acid ; but since aspartic acid is in all probability an amidogen-acid, and such acids are 
 always monobasic, it is rather to be supposed that the true formula of the salt dried 
 at 160 C. is 2C 4 H (i BaN0 4 .Ba 2 0. This formula requires only 55-0 per cent. Ba 2 ; the 
 greater proportion obtained by Dessaignes may have been due to the presence of car- 
 bonate of barium. (Gerhardt, Traite, i. 818.) 
 
 The normal calcium-salt is gummy, and tastes like the sodium-salt, The basic salt 
 frequently forms prismatic crystals containing 2C 4 H 6 CaN0 4 .Ca 2 O + 7H 2 ; according 
 to Dessaignes, it gives off 8 atoms of water at 160 C., and is then reduced tc 
 C 4 H 5 Ca*N0 4 . 
 
 Magnesium-salts. The normal salt forms crystalline crusts, soluble in about 16 pts. 
 of boiling water, insoluble in absolute alcohol. The basic salt obtained by dissolving 
 magnesia in the normal salt is a gummy mass. 
 
 Aspartate of Zinc is a white non-deliquescent salt. Aspartate of nickel is obtained 
 by evaporation in a green fissured mass. An aspartate of iron is precipitated on add- 
 ing a solution of basic aspartate of magnesium to sesquichloride of iron. 
 
 Aspartates of Copper. The normal salt of the active acid exists only in solution. 
 A basic salt is obtained by adding a solution of the normal barium-salt to a hot solu- 
 tion of sulphate of copper. The liquid on cooling deposits pale blue, very light crys- 
 tals which, according to Dessaignes, contain C 4 H 5 Cu 2 NO 4 .5H 2 (or rather, perhaps, 
 2C 4 H 6 CuNO 4 .Cu 2 + 9H 2 O), and give off their water at 160 C., leaving the anhy- 
 drous salt C 4 H 5 Cu 2 N0 4 . Inactive aspartate of ammonium forms a bluish precipitate 
 with copper-salts. (Wolff.) 
 
ASPASIOLITE ASPHALT. 425 
 
 Aspartatcs of Lead. The, normal lead-salt, C 4 H G PbN0 4 , is obtained by precipitate 
 ing a solution of acetate of lead with aspartate of potassium or basic aspartate of cal- 
 cium. On mixing an ammoniacal solution of normal acetate of lead with inactive 
 aspartate of sodium, a curdy precipitate is formed, and the filtered liquid, if diluted 
 with a considerable quantity of water, deposits, after two or three days, nacreous 
 crystals united in very hard spherical masses. These crystals are anhydrous, and 
 contain 63'88 per cent, of lead-oxide, agreeing with the formula 2C 4 H 6 PbN0 4 .Pb 2 O, 
 which requires 64 '5 per cent. Pb 2 0. The formula C 4 H 5 Pb 2 4 , analogous to that of 
 the basic aspartates examined by Dessaignes, would require 66'1 per cent, of lead- 
 oxide (Pasteur). The sodium-salt of active aspartic acid also forms a precipitate with 
 ammoniacal acetate of lead, and the liquid afterwards deposits hard radiated nodules 
 containing 65 per cent, lead-oxide ; these, however, are nothing but a basic acetate of 
 lead. (Pasteur.) 
 
 Aspartate of Mercury. Mercuric oxide, boiled with aspartic acid, forms a white 
 powder, containing, when dried at 100, 2C 4 H 8 HgN0 4 .Hg 2 0, a composition analogous 
 to that of Pasteur's basic lead-salt. (Dessaignes.) 
 
 Aspartatcs of Silver. When nitrate of silver is added to a slightly alkaline solution 
 of aspartate of ammonium, a precipitate is formed, which disappears on stirring, and 
 the liquid, after 24 hours, yields white, heavy, entangled crystals of a basic salt. The 
 mother-liquor, left to crystallise, deposits yellowish crystals of the normal salt, 
 C 4 H d AgNO 4 . The basic salt appears to be C 4 H 5 Ag 2 4 . This formula requires 
 66-86 per cent, oxide of silver, and the mean of several analyses made by different 
 chemists, and not differing by more than 0'2 per cent., gives 667 per cent. This salt 
 appears then to be really a dibasic aspartate. Pasteur finds, however, that the same 
 salt, when merely pressed between paper, and then dried for 24 hours at the ordinary 
 temperature, agrees in composition with the basic lead- and mercury-salts, its formula 
 being 2C'H 6 AgN0 4 .Ag 2 0. The active and inactive acids yield silver-salts identical in 
 composition. (Pasteur.) 
 
 Aspartate (?) of Ethyl. When malate of ethyl is saturated with dry ammonia- 
 gas, the liquid becomes heated, and in a few days solidifies to a radiated crystalline 
 mass, which, after being drained, and then washed with ether, consists of pure mala- 
 
 mate (or aspartate) of ethyl, ' 0. By further treatment with ammonia, it 
 
 is converted into malamide [ ? asparagine]. (Pasteur.) 
 
 ASPASIOLITE. A variety of cordierite [3(Mg 2 O.Si0 2 ) + Fe 2 O.Si0 2 + 
 2(2Al 4 3 .3Si0 2 )], in which the magnesia is partly replaced by water. The two 
 minerals crystallise in the same form, and crystals are found consisting partly of 
 cordierite, partly of aspasiolite, the most complete transitions from one to the other 
 occurring in the same specimen. Moreover, both minerals contain the same propor- 
 tions of silica and alumina ; but aspasiolite contains less magnesia and more water 
 than cordierite, the difference being that 1 at. of magnesium in the latter is replaced 
 by 3 at. of hydrogen in the former (or 1 at. of magnesia by 3 at. of water). Similarly 
 it is found that 1 at. of iron or manganese may be replaced by 3 at. H without altera- 
 tion of crystalline form. This kind of isomorphism, called polymeric isomorphism, 
 was discovered by Scherer; it was first noticed in the minerals cordierite and aspa- 
 siolite. (Pogg. Ann. Ixviii. 319.) 
 
 ASPERTAWXBTC ACID. A variety of tannic acid obtained by S ch war tz (Ann. 
 Ch. Pharm. Ixxx. 333) to be contained in woodruff (Asperula adorata). Schwarz 
 assigns to it the formula C 14 H 9 O 9 , but it does not appear to have been obtained in 
 a state of purity. (See also Rochleder, Ann. Ch. Pharm. Ixxxiii. 64.) 
 
 ASPERTTXiA ODOR AT A. The herb of this plant contains cumarin, aspertannic 
 acid (?), rubichloric acid, citric acid, and probably catechu. 
 
 ASPHAIiT. Compact Bitumen, Mineral Pitch, Jew's Pitch, Bitumen Judaicum, 
 Judcnpcch, Erdpcch, Bcrgpech, Goudron mineral. A smooth, hard, brittle, black, 
 or brownish-black, resinous mineral, having a conchoi'dal fracture, and a streak lighter 
 than the broken surface with which it is made. Specific gravity 1> to 1-68. Odour 
 bituminous, becoming stronger by friction. Melts at about 100 C., easily takes fire, 
 and burns with a bright, but very smoky flame. Like all bituminous substances, it is 
 a product of the decomposition of vegetable matter, consisting chiefly of .hydrocarbons, 
 with variable quantities of oxygen and nitrogen, and yields by dry distillation a small 
 quantity of ammoniacal water, a peculiar empyreumatic oil, and a residue of charcoal 
 mixed with variable quantities of inorganic matter. It dissolves partially in alcohol, 
 more easily in oils both fat and volatile ; it is also dissolved by alkalis and alkaline 
 carbonates. 
 
 Asphalt is found in most parts of the world, sometimes pure, sometimes associated 
 
426 ASPHALT. 
 
 with various minerals. The name earthy or crude asphalt is applied to various rocks 
 more or less impregnated with bitumen. Pure asphalt is found on the shores of the 
 Dead Sea, issuing from the earth in the liquid state at the bottom, and rising to tho 
 surface, where it forms solid lumps, which are thrown upon the shore. In Trinidad 
 there is a lake of bitumen l mile in circumference, cold and solid near the shore, but 
 gradually increasing in temperature and softness towards the centre. Asphalt is also 
 found, more or less pure, in Cuba, South America, and various parts of Europe. 
 
 At Seyssel, near the Khone (Dept. de 1'Ain), it forms a deposit 2500 ft. long and 
 800 ft. broad, yielding about 1500 tons annually. At Bechelbrunn and Lobsann, in 
 the Lower Rhine, a viscid bituminous mass is found, called graissc de Strasbourg, toge- 
 ther with a ferruginous sandstone, containing about 12 percent, of bituminous matter. 
 At Bastennes and Dax, in the D^partement des Landes, there is a siliceous sand, im- 
 pregnated with about 6 per cent, of bitumen. In the Val de Travers, Neufchatel, 
 there is a cretaceous formation, strongly impregnated with asphalt, which is used for 
 building purposes. In the British Isles, asphalt is found at the Poldice mine in 
 Cornwall ; near Matlock in Derbyshire ; at Haughmond Hill in Shropshire ; and at 
 the Hotwells near Bristol ; also in limestone near Glasgow ; in freestone near Edin- 
 burgh ; in the sandstone of Caithness ; and generally throughout the Orkneys. 
 
 Asphalt is separated from the minerals with which it is associated, either by boiling 
 with water, which causes the bitumen to run out in the melted state, or by the action 
 of hydrochloric acid, which dissolves carbonate of calcium and leaves the asphalt, or 
 with oil of turpentine, which dissolves out the bitumen. 
 
 The following table contains the results of analyses of various kinds of asphalt : 
 a is asphalt from Coxitambo inPeru ; b from Bastennes ; c from Pont-du-Chateau, 
 Auvergne ; d from the Abruzzi near Naples ; e from Pontnavey ; / from Cuba : 
 
 Boussingault.* Ebelmen.f Regnault.J 
 
 a bed e f 
 
 Carbon . . 88-63 8870 78-50 76-13 77'64 67'43 81-46 
 
 Hydrogen . 9'69 9'68 8-80 9-41 7'86 7'22 9'57 
 
 Oxygen > ,. fi8 .- 2-60 10-34 8'35 23-98) R . q7 
 
 Nitrogen} ' 1'65 2'32 1-02 1*7J 
 
 Ash 8-45 1-80 5-13 
 
 100-00 100-00 100-00 100-00 100-00 100-00 100-00 
 
 According to Boussingault (Ann. Ch. Phys. [2] Ixiv. 141), asphalt or compact 
 bitumen is a mixture of two definite substances, viz. asphaltene, which is fixed and 
 soluble in alcohol, and pctrolene, which is oily and volatile. The greater part of the 
 latter may be volatilised by distilling the asphalt with water. 
 
 Pctrolene (from the asphalt of Bechelbrunn) forms, when dried over chloride of 
 calcium and rectified, a pale yellow oil having a faint taste and bituminous odour. 
 Specific gravity 0-891 at 21 C. Does not become solid at 12 C. It stains paper, 
 and burns with thick smoke. Boils at 280, forming a vapour of specific gravity 9 -4 15. 
 It contains, according to Boussingault, 87*2 per cent, carbon and 12'1 hydrogen, agree- 
 ing nearly with the formula C 20 H 32 , which for a condensation to 2 vols. gives the 
 vapour-density 9-5. 
 
 Asphaltene is obtained pure by heating asphalt for 48 hours to 250 C., whereby 
 the petrolene is completely volatilised. It is a black solid substance, having a strong 
 lustre and conchoi'dal fracture. It becomes soft and elastic at about 300 C., decom- 
 poses before it melts, and burns like a resin. It gives by analysis 74-2 per cent. C, 
 and 9-9 H, whence Boussingault deduces the formula C 80 H 32 3 . Gerhardt prefers 
 C'^H^O 3 , and suggests that asphaltene may be formed by the oxidation of petrolene. 
 
 Asphalt-oil. Asphalt yields by dry distillation, a yellow oil consisting of hydro- 
 carbons mixed with a small quantity of oxidised matter. It begins to boil at 90 C. 
 but the boiling point gradually rises to 250. The portion boiling between 90 and 
 200 has a specific gravity of 0'817 at 15 C.; that which boils between 200 and 
 250 has a specific gravity (3f 0-868 at 15 C. Both portions gave by analysis about 
 87"5 per cent, carbon, 11-6 hydrogen, and - 9 oxygen, which is nearly the composition 
 of oil of amber. (Volckel, Ann. Ch. Pharm. Ixxxviii. 139.) 
 
 Asphalt-oil, treated with nitric acid, is transformed into a resin, having the odour 
 of musk and the taste of bitter almonds. On treating the oil with strong sulphuric 
 acid, part dissolves, while the rest floats on the surface. This latter, when decanted, 
 washed with potash, and rectified, yields an oily mixture, whose boiling point ranges 
 from 90 to 250 C., and density from 0*784 to 0'867 at 15 C. Subjected to frac- 
 tional distillation at intervals of 20 or 30 C., it yields a number of oils gradually 
 
 * Ann. Ch. Phys. [2] Ixxiii. 422. f Ann. Min. xv. 523. J Dingl. polytechn. J. Ixviii. 201. 
 
ASPHODELUS ASPIRATOR. 427 
 
 increasing in density, but agreeing very nearly in composition, the mean result of their 
 analysis being 87'5 per cent, carbon, and 12'5 H, a proportion agreeing with the 
 formula wC 3 H 5 . It agrees also with Boussingault's analysis of petrolene. All these 
 oils have nearly the same odour, are insoluble in water, but very soluble in alcohol 
 and ether. Strong sulphuric acid scarcely attacks them. They are insoluble in strong 
 nitric acid, and on boiling the liquid, the nitric acid volatilises, and there is formed a 
 very small quantity of a heavy yellow oil. 
 
 Asphalt was used by the ancient Egyptians in embalming, and appears to have been 
 employed in the construction of the walls of Babylon. It is now used, mixed with 
 sand, chalk, ground sandstone, &c., for pavement, for making water-tight tanks and 
 covers, as a coating for tubes of glass and iron used for conveying gas or water, and for 
 various other purposes of like nature. 
 
 Artificial or Gas-tar Asphalt is a mixture of sand, chalk, or lime-stone, with the 
 thick pitchy residue obtained by evaporating off the more volatile portions of gas-tar. 
 The mineral substance must be strongly heated to expel moisture and adhering air, 
 the presence of which would prevent the pitch from penetrating thoroughly into the 
 pores of the mineral, and added to the pitch while in the melted state. The pitch 
 should also be very strongly heated, but not enough to char it. This artificial asphalt 
 is used in the same way as the natural asphalt, for pavements, tanks, &c. 
 
 ASPHODELUS. The bulbs of Asphodele de Sardaigne, of Asphodelus racemosus, 
 and other species of the same genus, are said to contain a fermentable substance from 
 which alcohol may be prepared. According to Landerer, an excellent glue may bo 
 obtained from the bulbs of A. racemosus and A. fistulosus by washing them with 
 water, drying them thoroughly in a stove, grinding them to coarse powder, and 
 mixing the powder with water. 
 
 ASPIRATOR. An apparatus first devised by Brunner for drawing a stream of 
 air through a tube or other vessel. The simplest form of it is a cylindrical vessel 
 A (fig. 76), of zinc or tin plate to hold water, having a cock a near the bottom, and 
 three apertures closed with corks b, c, d on the 
 top. b is connected with the vessel through 
 which the stream of air is to be drawn ; c is for 
 the insertion of a thermometer, and d to pour 
 in water. The vessel A being filled with water, 
 the apertures c and d closed, and the cock a 
 opened, the water runs out ; and as air can only 
 enter by the bent tube e, inserted into the 
 opening b, a stream of air is drawn through the 
 apparatus with which the other end of this tube 
 is connected, the volume of air thus drawn 
 through being exactly equal to that of the 
 water which runs out at A. Instead of the 
 metal cylinder, a glass vessel may be used, 
 having a stopcock at the lower part of its 
 side. 
 
 Regnault, in his analysis of air, used a* cy- 
 lindrical metal vessel with conical terminations, 
 and having at the bottom, a stopcock to which was attached a short glass tube bent 
 upwards, so that the small column of liquid which remained in it when the vessel was 
 emptied of water might prevent air from entering at the bottom The advantage of tho 
 conical terminations is that the vessel can be more completely filled and emptied, 
 and the volume of water which runs from it, more exactly measured. 
 
 In all these forms of aspirator, the refilling of the vessel with water is yery 
 troublesome, especially when large quantities of air are to be drawn through. To 
 obviate this inconvenience, an aspirator has been contrived by Brunner, consisting of 
 two equal cylindrical vessels placed one above the other and communicating by tubes 
 which can be opened or closed, so that, when the water has run from the upper to 
 the lower vessel, the apparatus, turning for the purpose on a horizontal axis, may be 
 inverted so as to bring the empty vessel to the bottom, and the full one to the top ; 
 the water may then be again made to run without the trouble of refilling. 
 
 M ohr's aspirator has the form of an ordinary gasometer, consisting of two cylindrical 
 vessels, the inner of which, of rather smaller diameter than the outer, is closed at top, 
 and inverted in the outer which contains water. The inner vessel is balanced by a 
 weight passing over a pulley, as in the large gasometers used at gas-works. The vessel 
 through which the air is to be drawn is connected with the inner vessel by a bont 
 tube passing through the outer vessel near the bottom and terminating within the 
 inner vessel. 
 
428 
 
 ASSACOU ASSAMAR. 
 
 Fig. 77. 
 
 A simple apparatus, serving both for aspirator and perspirator is described by Dr. 
 F. Guthrie (Phil. Mag. [4] xv. 64). 
 
 An aspirator which works by a constant stream of water and does not require 
 any filling or emptying of vessels, has been contrived by M. "W. Johnson (Chem. 
 Soc, Qu. J. iv. 186). The principle of this apparatus is the same as that of the water- 
 blast used in the Hungarian mines. The apparatus 
 consists of a small hollow cylinder A, of brass or glass, 
 open at both ends, and connected with the vessel 
 through which the air is to be drawn, by the lateral 
 tube C. A straight glass tube B is fitted to the lower 
 end of the cylinder A, and the upper end of that 
 cylinder is attached by a caoutchouc tube to a water- 
 tap supplying a constant stream. On opening the tap, 
 the water, as it runs down, carries the air in the cylin- 
 der A along with it and the air in the lateral tube C 
 is then driven in by the external pressure. In this 
 manner, a stream of air is made to pass from C to A as 
 long as the water is running. It is best not to open 
 the tap to the full. For a cock f of an inch in 
 diameter, the cylinder A may be 2 in. long and f in. 
 wide ; B 1 in. long and f in. wide ; C also 1 in. long 
 and | in. wide. The volume of air drawn through this 
 aspirator is not equal to that of the water which runs 
 away. With the tube B t 8 in. long and | in. wide, John- 
 eon found that, for every cubic foot of air drawn in, only 
 0*69 cub. in. of water was expended. It is clear, 
 therefore, that this form of aspirator cannot be used 
 when the volume of air drawn in is to be exactly 
 measured. In that case one of the aspirators before de- 
 scribed must be used. When only small quantities of 
 water are run out, it is sufficient to receive the water 
 in a graduated measure and determine its volume 
 directly. When a large aspirator is used and has to 
 
 be filled several times, its capacity must be previously determined by filling it with 
 water from a flask of known capacity. 
 
 This volume of air determined by direct measurement of the water run out, must of 
 course be reduced to the standard pressure and temperature, C. and 760 mm., the co- 
 efficient of expansion for each degree centigrade being 0'003665. A correction is also 
 required for the quantity of aqueous vapour in the air, which is saturated with mois- 
 ture. To determine the alteration of volume thus produced, we must look in the tables 
 of the tension of aqueous vapour for the tension corresponding to the observed tem- 
 perature. Let this tension expressed in millimetres of mercury be/; also let h denote 
 the height of the barometer, t the temperature in centigrade degrees ; v the observed 
 and v' the corrected volume of the air : then 
 
 *-/ 1 
 
 ' 760 1 + 0-003665 . t 
 
 ASSACOU or TJSS ACTT. The Brazilian name for the Hura brasiliensts Martins, 
 a euphorbiaceous tree, the bark and sap of which contain an acrid very poisonous 
 principle. The thickened sap and the decoction of the bark exert an emetic action, 
 produce ulcerating pustules on the skin, and are used as a remedy for elephantiasis. 
 The natives also use them to prepare poisonous drinks, against which no antidote is 
 known. (Merat and Gilbert, Pharm. Centr. 1849, p. 30.) 
 
 ASSAMAR. (From assare to roast, aed amarus bitter.) This name was given 
 by Reichenbach to the peculiar bitter substance produced when gum, sugar, starch, 
 gluten, meat, bread, &c. are roasted in the air till they turn brown. Reichenbach 
 (Ann Ch. Pharm. xlix. 3) prepares it by roasting thin slices of bread till they become 
 black-brown, treating the pulverised product with absolute alcohol, evaporating to a 
 syrup, again treating with alcohol, &c. till a residue is obtained completely soluble in 
 alcohol. The alcoholic solution is then mixed with ether, which precipitates a peculiar 
 brown substance ; the decanted liquid is evaporated ; and the residue carefully heated 
 till it is dry. Volckel (Ann. Ch. Pharm. Ixxxv. 74) prepares assamar in a similar 
 manner, from the brown tarry liquid obtained by the dry distillation of sugar or 
 caramel, after neutralising the acid contained in the liquid with carbonate of sodium, 
 an- 1 evaporating. 
 
 Aswamar, according to Reichenbach, is a yellow transparent solid ; but according 
 
ASTER AT AC AMITE. 
 
 429 
 
 to Volckel, it is a reddish-yellow syrupy liquid, which does not solidify till it begins 
 to decompose. It is extremely hygroscopic, and dissolves in water in all proportions. 
 When heated, it melts (R eichenbach), becomes more fluid, and at 100 C., decomposes 
 and becomes darker in colour, after which it no longer dissolves completely in water 
 (Volckel). The aqueous solution is neutral, and reduces nitrate of silver when 
 heated. Assamar is dissolved by potash, and acids precipitate from the solution, a body 
 of different composition. Volckel assigns to assamar the formula C**H W 1 *; but it is 
 doubtful whether the substance so-called is a definite compound, or has ever been 
 obtained in the pure state. 
 
 ASTER-TRXPOXiXITM. 8m Starwort. The ash of this plant, which grows in 
 salt-marshes, is very rich in chloride of sodium. The several parts of the plant 
 gathered towards the end of September, were found by Harms (Ann. Ch. Pharm. 
 xciv. 247) to yield ash of the composition and amount given in the following table : 
 
 
 Root-leaves. 
 
 Stems. 
 
 Stem-leaves. 
 
 Flowers. 
 
 Ash per cent .... 
 
 14-9 
 
 87 
 
 16-2 
 
 9-4 
 
 Containing, in 100 pts., after 
 
 
 
 
 
 deducting charcoal and sand : 
 
 
 
 
 
 Carbonic acid (anhyd.) 
 
 3-4 
 
 3-3 
 
 4-2 
 
 37 
 
 Sulphuric acid (anhyd.) 
 
 27 
 
 1-8 
 
 4-1 
 
 10-5 
 
 Phosphoric acid (anhyd.) 
 
 2-0 
 
 0-6 
 
 17 
 
 10-8 
 
 Silica (anhyd.) 
 
 0-6 
 
 0-5 
 
 0-8 
 
 1-0 
 
 Chloride of sodium 
 
 65-5 
 
 68-5 
 
 60-2 
 
 30-0 
 
 Chloride of potassium 
 
 37 
 
 14-1 
 
 
 
 
 
 Soda .... 
 
 
 __ 
 
 14-0 
 
 1-4 
 
 Potash .... 
 
 13-6 
 
 2-5 
 
 6-1 
 
 25-4 
 
 Lime .... 
 
 6-0 
 
 4-5 
 
 4-8 
 
 7-2 
 
 Magnesia . . . 
 
 2-2 
 
 2-2 
 
 17 
 
 57 
 
 Sesquiphosphate of iron 
 
 1-1 
 
 2-1 
 
 2-3 
 
 4-0 
 
 Manganaso-manganic oxide 
 
 trace 
 
 trace 
 
 trace 
 
 trace 
 
 A native sulphate of magnesium and sodium, S0 4 MgNa.2H 2 
 occurring in white, opaque, prismatic crystals, together with ordinary sulphate of 
 magnesium, in the bitter salt-marshes on the eastern side of the mouth of the Volga. 
 
 ASTRAXiXTE. A glass flux resembling aventurin, but containing crystals of a 
 cuprous compound, which by reflected light exhibits a dichroitic iridescence of dark 
 red and greenish-blue. To prepare it, a mixture of 80 pts. of silica, 120 lead-oxide, 
 72 carbonate of soda, and 18 anhydrous borax, is fused either with 24 pts. of scale 
 oxide of copper, and 1 pt. of scale oxide of iron, or with 5 pts. of lime, 26 scale oxide 
 of copper, and 2 scale oxide of iron. The mixture is fused in a hessian crucible, at- 
 the heat of an ordinary air-furnace, and left to cool slowly in the furnace. The first 
 mixture melts more easily than the second, and yields larger crystals. The dichroitic 
 iridescence is particularly beautiful on cut and polished surfaces. (Pettenkofer, 
 Abhandl. d. naturw. techii. Commission bei d. Akad. d. Wiss. zn Miinchen, p. 134.) 
 
 ASTROPHlTXiXiXTE. A variety of mica found at Brevig in Norway. It con- 
 tains silica, alumina, ferric oxide, magnesia, potash, soda (a trace), ferrous oxide, 
 manganous oxide, lime, and about 3 per cent, of water. The amount of iron is 
 unusually large. Fluorine is absent. Before the blowpipe it melts easily, and with 
 intumescence. Colour pinchbeck-brown, varying to nearly a golden-yellow in the 
 thinner parts. The crystals are often united in beautiful stellate and floral groups : 
 hence the name. (Scheerer, Berg- u. hiittenmannische Zeitung, 1854, s. 240.) 
 
 ATACAMXTE. A native oxychloride of copper, originally found in the desert 
 of Atacama in Peru, and since observed in other localities, viz. in some silver mines in 
 Peru, in the districts of Huasco Bajo and Aconcagua in Chili, in the lavas of Vesu- 
 vius, and in the mines of Schwarzenberg in Saxony. According to the analyses of 
 Klaproth, J. Davy, Ulex, and Mallet, it contains CuCl.SCuHO, or CuCl+ 3(CuO.HO). 
 Berthier (Kammelsb. Handw. i. 55), found in a specimen from Cobija, twice the amount 
 of water given by the above formula. F. Field (Chem. Soc. Qu. J. vii. 194), deduces 
 from his analysis of a specimen from Copiapo in Chili, the formula CuCl + SCuO + 
 5HO, or CuC1.3CuIIO.H 2 0. It forms small rhombic crystals, varying in colour from leek 
 to emerald green, and generally aggregated in crystalline groups. According to Mon- 
 teiro (Phil. Mag. [4] xiii. 470), it occurs at Serra do Bembe near Ambriz, on the 
 west coast of Africa, in small translucent crystals, ooP . P oo, on malachite and quartz. 
 It dissolves easily and completely in acids, and in ammonia. It is used for the ex- 
 traction of copper. 
 
430 ATHAMANTA ATHERI ASTITE. 
 
 ATHAMAITTA OREOSEZiIKTUIVT. The root and seeds of this plant contain 
 a peculiar bitter substance, not yet examined, together with athamantin (see next 
 article). The leaves contain, not athamantin, but a bitter principle and a volatile oil, 
 which is obtained by distilling the herb with water. This oil has the composition of 
 oil of turpentine, C"H 16 ; it smells like elder, has a density of 0*841, and boils at 
 163 : C.' With hydrochloric acid gas, it forms an uncrystallisable liquid, which is 
 colourless after distillation, lighter than water, and boils at 190 C. It does not appear 
 to be related, in composition or properties, either to athamantin or to oil of valerian, 
 which is produced by the decomposition of the latter. (Schnedermann and 
 Winckler, Ann. Ch. Pharm. li. 336.) 
 
 ATHAXVEAIffTIN 1 . C'- 4 H 30 7 . (Gm. xii. 101 ; G-erh. iv. 269.) -A substance exist- 
 ing in the root and seeds ofAtkamanta orcosclimim, and other species of the same genus. 
 It was first obtained in an impure state by Winckler (Buchn. Repert. xxvii. 169), 
 afterwards prepared pure and more completely examined by Schnedermann (Ann. 
 Ch. Pharm. li. 315). It is extracted by treating the roots and seeds with alcohol. 
 The solution, if not too concentrated, yields the athamantin, by spontaneous evapora- 
 tion, in crystals, which may be purified by pressure and recrystallisation. It forms 
 colourless, fibrous, silky crystals, or sometimes rectangular prisms with truncated sum- 
 mits ; has a rancid soapy odour, and a slightly bitter acrid taste. It is insoluble in 
 water, and melts in it at the boiling heat, in drops which sink to the bottom of the 
 vessel. It dissolves readily in alcohol and ether, and the solutions are not precipitated 
 by metallic salts. It melts between 60 and 80 C. It does not volatilise undecom- 
 poged, although it can sustain a tolerably high temperature without decomposition. 
 By dry distillation, it yields valerianic acid and other products. 
 
 Melted athamantin absorbs hydrochloric acid gas, and appears to enter into com- 
 bination with it, but on raising the temperature to 100 C., decomposition takes place, 
 and the athamautin is resolved into valerianic acid and oreoselone : 
 
 2C 5 H 10 2 + C 14 H 10 3 
 
 Athamantin. Valerianic Oreoselone. 
 acid. 
 
 When hydrochloric acid gas is passed into an alcoholic solution of athamantin, the 
 products formed are oreoselone and valerate of ethyl. Sulphurous acid acts on athaman- 
 tin like hydrochloric acid, a crystalline compound being formed at first, and soon after- 
 wards oreoselone, valerianic acid, and sulphurous acid gas. Concentrated sulphuric acid 
 dissolves athamantin and decomposes it in like manner. Athamantin heated with 
 caustic potash, yields valerate of potassium, and a white amorphous substance, which 
 appears to be a hydrate of oreoselone. Lime-water and baryta-water act in the same 
 manner, but more slowly. (See OREOSELONE and PEUCEDANIN.) 
 
 Trichlorathamantin, C-'II 27 C1 3 7 , is a light yellow resinous body, produced by mixing 
 an alcoholic solution of athamantin with water, and cautiously adding dilute chlorine- 
 water, till the liquid smells slightly of chlorine. A corresponding bromine-compound 
 appears to be formed by treating athamantin with bromine-water. 
 
 Trinitratkamantin, C 2I H 27 (N0 2 ) 3 7 , is formed, together with other substitution- 
 products, by the action of cold fuming nitric acid on athamantin. Precipitated by 
 water, it is a yellow pulverulent substance, scarcely wetted by water, easily soluble in 
 alcohol, ether, and ammonia, slightly in dilute nitric acid. (Geyger, Ann. Ch. Pharm. 
 ex. 359.) 
 
 ATHANOR or ACACTOR. Tiger Henricus, Fourncau des paresseux. A kind 
 of furnace, which has long since fallen into disuse. The long and tedious operations 
 of the ancient chemists rendered it a desirable requisite, that their fires should be 
 constantly supplied with fuel in proportion to the consumption. The athanor furnace 
 was peculiarly adapted to this purpose. Beside the usual parts, it was provided with 
 a hollow tower, into which charcoal was put. The upper part of the tower, when 
 filled, was closely shut by a well-fitted cover ; and the lower part communicated with 
 the fire-place of the furnace. In consequence of this disposition, the charcoal sub- 
 sided into the fire-place gradually as the consiimption made room for it ; but that 
 which was contained in the tower was defended from combustion by the exclusion of 
 a proper supply of air. U. 
 
 ATHAR or ATTAR. The Indian name of volatile oil of roses. 
 
 ATHERXASTXTE. Thf name given by Weibye to a mineral from Arendal, 
 bearing an external resemblance to scapolite. In composition it appears to be related 
 to epidote, as will be seen by the following comparison of its analysis by Berlin 
 (Pogg. Ann. Ixxix. 302)- with that of epidote from Arendal by Scheerer (ibid. 
 xcv. 503). 
 
ATLAS ORE ATMOSPHERE. 431 
 
 Atheriastite. 
 
 Silica .... 38-00 
 Alumina . . . 24-10 
 Ferric oxide . . . 6'22 
 Lime . . . .22-64 
 Magnesia . . . 2*80 
 Water .... 6-95 
 
 100-71 100-05 
 
 Berlin does not state whether the iron in atheriastite is present as a ferrous or as a 
 ferric compound ; but it is probably all in the form of ferric oxide. (S c h e e r e r, Handw. 
 d. Chem. 2 te Aufl. i. 405.) 
 
 AT&AS ORE. See MALACHITE. 
 
 ATXiAS SPAR. See SATIN SPAR. 
 
 ATZKERYTKRIXQ 1 . The name given by Kane (Compt. rend. ix. 656) to a pro- 
 duct which volatilises in red vapours, and condenses in reddish-green laminae, in the dry 
 distillation of litmylic acid (erythrolitmin) and litmic acid (a mixture of azolitmin 
 and spaniolitmin), with lime. 
 
 ATMXDOSCOPX:. An instrument invented by Bab in et (Compt. rend, xxvii. 
 529) to measure the rate of evaporation. 
 
 ATMOSPHERE. The gaseous envelope which surrounds any solid or liquid 
 body is called an atmosphere (OT/XOS smoke, fftydipa globe) ; thus we speak of the atmo- 
 sphere of oxygen which spongy platinum attracts to its surface, or of the reduction of 
 a metal in an atmosphere of hydrogen. The term atmosphere is, however, especially 
 employed to designate the gaseous matter which encircles the solid and liquid portions 
 of the earth's surface, forming the air or earth's atmosphere. 
 
 Of the existence of matter above the visible crust of the globe we have striking 
 evidence in the resistance offered to bodies moving near the earth's surface and 
 in the effects produced by wind ; but the most direct proof that the air is attracted 
 by the solid and liquid portions of the earth's body, or that the air has weight, is 
 afforded by the fact that a vessel filled with air weighs more than the same vessel 
 from which the air has been removed, and that a closed vessel filled with air weighs 
 less in the atmosphere than it does in a vacuum. That the air possesses weight was 
 suspected even before the time of Aristotle ; but Galileo, in 1640, was the first who gave 
 the right explanation to the fact observed by the Florentine pump-makers, that they 
 were unable to raise water by a suction-pump more than 32 feet, and supposed by 
 them to show that nature had a " horror vacui." Galileo's explanation was beauti- 
 fully verified by his pupil Torricelli, who argued that, if the atmospheric pressure 
 supports a column of water 32 feet in height, it must support a column of mercury, 
 which is nearly fourteen times heavier than water, of about 30 inches in height ; 
 and thus the first barometer was constructed, the empty space above the mercury in 
 the tube being called, from its discoverer the, Toricellian vacuum. 
 
 The atmosphere, then, having weight, or obeying the laws of gravitation, forms a 
 part of the earth's body, and accompanies the solid and liquid portions in their axial 
 and orbital motions. The height to which the atmosphere extends above the earth's 
 surface is not the same at all points, since, owing to the increase of the attractive 
 force at the poles and its diminution at the equator, and to the action of the 
 centrifugal force, as also to the increase of temperature, the atmosphere presents, 
 like the earth's solid body, the form of a spheroid, whose polar is considerably 
 shorter than its equatorial diameter. The absolute height to which the atmosphere 
 extends above any point on the surface of the earth has not been determined 
 with any degree of certainty: for, as air is an expansive fluid, and the volume 
 which a given quantity of air occupies is directly dependent upon the pressure 
 and temperature to which it is exposed (in accordance with the known laws regu- 
 lating the expansion and contraction of gases), the density of the atmosphere is not 
 uniform, but diminishes as the distance from the earth's surface increases: the 
 exact point at which the atmosphere terminates is thus very difficult to determine. 
 That there is, however, a limit of the earth's atmosphere is rendered certain from the 
 fact, ascertained by the observations of the occultations of stars or satellites, that our 
 moon and most of the planets are destitute of an atmosphere like ours, which 
 could not be the case if the terrestrial air were diffused throughout space. Dr. Wol- 
 laston supposed that a gas cannot expand beyond a certain limit, and Faraday has 
 shown that in the case of the vapour of mercury such a limit really exists : hence 
 there can be no doubt that there is a definite limit to the atmosphere ; and, from 
 calculations of the time during which the twilight extends to the zenith, it appears 
 
432 ATMOSPHERE. 
 
 that the atmosphere reaches, in a state of sensible density, to the mean height of from 
 forty to forty-five miles above the earth's surface.* 
 
 Barometric observations at various heights above the sea-level prove conclusively 
 that Galileo's theory of atmospheric pressure is correct. The first of these barometric 
 measurements, made on the Puy-de-D6me by Pascal's advice in 1648, showed that the 
 column of mercury supported by the atmosphere sinks as the distance from the earth's 
 surface increases ; thus, at the sea-level, the mean height of the barometric column is 
 760 millimetres (29'92 English inches), whereas in Potosi, at a height of 13,220 feet, the 
 mercury sinks to a mean level of 471 millimetres. The average weight, then, of the 
 atmosphere at the level of the sea is, in our latitudes, that of a column of mercury 
 700 mm. in height, or equal to a pressure of 103*33 kilogrammes on a square deci- 
 metre (nearly 15 pounds on a square inch). This weight, the human body, in common 
 with all substances existing at the bottom of the ocean of air, has to carry ; and 
 although it may at first sight appear remarkable that the animal frame should be able 
 without discomfort to bear a pressure amounting to several tons, yet it is certain that 
 not only is this the case, but that our bodies are arranged so that we cannot exist with- 
 out this pressure ; and as an effect of the weight of the air, it has been shown by the 
 brothers Weber, that the human thigh-bone is, in certain positions of the body, re- 
 tained in its place, together with the ball and socket hip-joint, only by atmospheric 
 pressure ; it is well known also that persons remaining for any length of time at great 
 heights above the earth's surface are inconvenienced by haemorrhage from the nose, 
 eyes, and mouth, owing to the small blood-vessels, unsupported by the atmospheric 
 pressure, being unable to withstand the forcible propulsion of the blood through the 
 system. 
 
 The relation according to which the density of the air diminishes in ascending, is 
 easily deduced from the well-known law of Mariotte, that the density of a gas 
 is directly proportional to the pressure to which it is subject ; whence it follows that, 
 alterations of temperature and variations in the force of gravity at different heights 
 not being considered, the density diminishes in a geometrical ratio, as the height in- 
 creases in an arithmetical ratio. It has been found by experiment that, when the 
 barometer stands at a height of 760 mm. it is necessary to ascend 10'5 metres in 
 order to effect a fall of 1 millimetre in the barometric column, or to bring the mercury 
 
 759 
 
 to stand at 759 mm., or at 760 = mm. Now we may assume, without appre- 
 ciable error, that the air throughout this space of 10 '5 metres is of equal density; 
 
 759 
 at a height, then of 10-5 metres the pressure is 760 : hence the air in the next 
 
 759 
 10-5 metres has only a density of - of what the lower layer had ; and therefore, 
 
 in ascending through the second 10*5 metres, the barometer does not fall 1 millimetre, 
 
 759 
 but only ,= of a millimetre, so that at a height of twice 10'5 metres, the barometer 
 
 760 750 759 /759\ 2 
 
 will stand at 760 = ^rrr = 760 I ^-, } ; and as the density of the third layer 
 
 760 7oO \7t>0/ 
 
 of 10-5 metres is ^r^- times less than that of the second, the barometer at the height 
 
 ' /759\ 2 /759\ 2 /759\ 8 
 
 of three times 10'5 metres, will be 760 I^QO) ~ \T^o) = ^ 6 * ( 760 ) ' andsoon - If 
 
 then, at two places the barometer stands respectively at B = 760 l^~) and 
 /759\ m \'t>y/ 
 
 B' = 760 (= ) , their difference in elevation is 10'5m x (n ni); hence, from 
 \760/ 
 
 these two equations the difference in height, ZT, between these two points expressed in 
 metres is 
 
 H = 18363 (log B - log 2?') 
 or in English feet 
 
 H = 60246 (log B - log B'). 
 
 By means of this formula, we find that the pressure is diminished to half its original 
 amount, and therefore the air expanded into double its original volume, at a height of 
 5528 metres or 18,136 ft. above the level of the sea, and that at a height of twice 
 5528 metres, the pressure is reduced to ^ of its original amount, and so on. 
 
 The mean temperature of the atmosphere, like its density, is not equal throughout 
 the mass, but diminishes as the distance from the earth's surface increases, so that, at 
 a certain height above the sea-level, different for different latitudes, we arrive at a 
 
 * In order to give an idea of the relation between the earth's diameter and the height of the atmo- 
 sphere, it may be stated, that if we represent the earth by a globe of 1 foot in diameter, the atmosphere 
 will be represented by a layer of air ^ of an inch in height. 
 
ATMOSPHERE. 433 
 
 lino above which the mean temperature of the air does not rise higher than the freezing 
 point, and this line is called the level of perpetual snow. This regular diminution of 
 temperature in the higher regions of the atmosphere is to be attributed mainly to two 
 causes : 1st, to the fact that the air absorbs but a small portion of the heating rays of 
 the sun in their passage to the earth, the lower zones of the atmosphere being heated 
 by contact with the warmer solid and liquid crust of the globe ; and, secondly, to the 
 increase of latent heat which all gases undergo on rarefaction, producing a diminution 
 in temperature. Besides this regular alteration of mean temperature of the various 
 zones of air above the earth, the various portions of the atmosphere exhibit great and 
 constant variation in temperature, owing to the unequal heating effects produced by 
 the sun on the earth in various latitudes and at various times. The mean tem- 
 perature of any place, and therefore of the air above that place, is the resultant of the 
 amount of heat received from the sun, and that lost by radiation. These two con- 
 trolling causes are, however, never constant, either in the same or in different places, 
 and hence the temperature is continually varying. The chief factor representing the 
 change of temperature, is the height to which the sun rises above the horizon, and the 
 intensity with which any point on the earth's surface is heated, is proportional to the 
 cosine of the sun's zenith-distance at that point ; thus, in the torrid zone, the sun's 
 zenith-distance varies from to 33'5, or the cosine from 1 to 0-917, whilst in the 
 temperate and frigid zones the cosine of the angle varies from 0-930 to 0-367, and 
 from 07 31 to 0. We see from these numbers that, although many other circum- 
 stances, such as duration of day and night, and the thickness of atmosphere through 
 which the sun's rays have to pass affect the temperature, the warm climate of the 
 torrid zone is not subject to such variations as occur in the other portions of the globe. 
 The height at which the mean atmospheric temperature sinks below C., or the 
 height of the snow-linq, in different latitudes, is determined by many circumstances 
 besides those already mentioned, as, for instance, the geographical relations of the 
 country, neighbourhood of large masses of water, &c. ; thus the snow-line on the 
 northern slope of the Himalaya is found at a height of 15,600 ft., whilst on the southern 
 slope it reaches only 12,200 ft. above the sea. Still the general descent of the line of 
 perpetual snow with increase of latitude is, notwithstanding these local irregularities, 
 plainly seen; thus, under the equator, the snow line is not reached until 15,207 ft., 
 whereas, under the latitude of 60, it is found at 3818 ft., and in latitude 75, at 
 only 1016 ft. above the sea-level. 
 
 In passing through the atmosphere, a portion of the solar rays is absorbed, the 
 amount of this absorption depending upon the thickness of the layer of air through which 
 the rays pass. Pouillet (Pogg. Ann. xlv. 25 and 481) concluded, from his own ex- 
 periments, that when the sun is in the zenith and the atmosphere clear, the amount 
 of the sun's heat which is absorbed by passing through the air, varies from 18 to 25 per 
 cent, of the quantity which enters the atmosphere. 
 
 The light of the sun is also partially absorbed and reflected in its passage through 
 the air, and, according to Clausius (Pogg. Ann. Ixxii. 294), out of 1000 rays of direct 
 sunlight entering the atmosphere, 750 reach the earth direct, whilst 186 are reflected as 
 diffuse light, and 64 are absorbed. For the more refrangible chemically active rays, 
 Bunsen and Roscoe have lately determined the amount of atmospheric absorption and 
 reflection : for the numerical results of these experiments the reader is referred to the 
 article on the Chemical Action of Light. Besides suffering absorption and reflection, 
 every ray of light which enters the atmosphere otherwise than perpendicularly to the 
 limiting surface, undergoes refraction, or is bent out of its coiirse in the direction of tho 
 denser medium, so that, as we see the object in the direction of the tangent to the 
 curve as it enters the eye, all celestial objects appear higher than they really are. Ac- 
 cording to the experiments of Biot and Arago, the refractive index, from the absolute 
 vacuum into air at C. and 076 m. pressure of mercury, is 1 '000294 ; and hence the 
 refractive power of the air is equal to 0*000588.* 
 
 Owing to the unequal heating effect which the sun produces on the various portions 
 of the earth's surface, either from general or local causes, the temperature of the 
 atmosphere varies in every part of the globe, and in the same part undergoes 
 continual change, thus producing the motion of masses of air which we call wind. 
 Winds are invariably caused by the ascent of a heated mass of air, and the motion of 
 a colder mass to fill up the space thus left vacant ; the former of these gives rise to 
 currents in the higher regions of the atmosphere, whilst the latter produces the hori- 
 zontal currents which we observe at the surface of the earth. Winds may either be con- 
 fined to very narrow limits, as for example the sea and land breezes seen on every coast, 
 or they may extend over a large portion of the globe, as is the case with the trade winds. 
 The former are caused by local circumstances depending upon the unequal heat-absorb* 
 
 * If the index of refraction be = n, the refractive pr.wor is n- 1. See LIGHT. 
 VOL. I. F F 
 
434 ATMOSPHERE. 
 
 ing and radiating power of the sea and land, whilst the Litter depend upon the iraequnl 
 distribution of temperature throughout the globe, being caused by the rise of hot air 
 from the equatorial zones, inducing horizontal currents to stream in from the colder polar 
 regions. These polar currents would, if the earth were at rest, move directly south 
 and north to the equator ; but, owing to the earth's axial motion from west to east, 
 they pass continually over latitudes having a velocity of rotation greater than that of 
 the current, which therefore acts as a resistance towards the east, or as a north- or 
 south-east wind. 
 
 Composition of the Atmosphere. 
 
 It was not until the year 1774 that the true composition of the atmosphere was 
 pointed out by Lavoisier. Before this time, the air was spoken of as one of the four 
 elements, together with fire, earth, and water ; and it was only during the few years 
 preceding this date that the vague impressions of speculative philosophers were ex- 
 changed for the careful observations of Priestley and Scheele, whose discovery of 
 oxygen had paved the way for the knowledge of the exact composition of the atmo- 
 sphere. In November 1774, having the advantage of acquaintance with Priestley's 
 previous discovery of the vital air procured from red precipitate, Lavoisier announced 
 to the world that the atmosphere consists of two gases, one of them being essential to 
 life, and the other incapable of supporting respiration or combustion. These two gases 
 he named oxygen (o|i/, acid, and yev to give rise to) and azote (a privative, and 
 fa)), life) or nitrogen, and he found that the first of these gases occupies about one-fifth 
 by bulk of the atmosphere, the other occupying the remaining four-fifths. Besides 
 these two gases, which form by far the largest portion of the atmosphere, many other 
 substances occur in the air, which although present in comparatively small quantities, 
 play so important a part in the action of the atmosphere on our globe that they 
 cannot be regarded as accidental constituents : these substances are, aqueous vapour, 
 carbonic acid, ammonia, and organic decomposing matter. The atmosphere also con- 
 tains traces of very many other bodies which may be considered as foreign or accidental 
 constituents, such as nitric acid, sulphurous acid, carbonic oxide, hydrocarbons and minute 
 solid particles which are seen floating about in ihe air by the light of a sunbeam. 
 
 Since the time of Priestley, Scheele, and Lavoisier, the determination of the quanti- 
 tative composition of the atmosphere has been made the subject of experiment by 
 many of the most eminent chemists of the present century ; but in spite of these 
 numerous investigations, the relative distribution of the component gases of the atmo- 
 sphere is still but imperfectly known. 
 
 At the commencement of this century, there was much difference of opinion amongst 
 scientific men as to the true composition of the atmosphere : Prout, Dobereiner, and 
 Thomson considered the atmosphere to be a chemical compound of 20 volumes of 
 oxygen, and 80 volumes of nitrogen, whilst D alt on (Manchester Memoirs, 2 Ser. 
 Tol. i. p. 244) contended that the atmosphere is a mere mechanical mixture, but sup- 
 posed that the relative amounts of the two gases varied according to their specific 
 gravities at different heights above the earth's surface, the oxygen increasing in 
 quantity the nearer the sea-level was approached, and the amount of nitrogen becom- 
 ing larger as the distance from the surface of the earth increased. 
 
 That the determination of the amount of oxygen which air in different localities 
 contains, should have excited the interest of men of science as soon as the discovery of 
 the true composition of the air was made, does not seem remarkable, when we bear in 
 mind the direct dependence of all life upon this element, and the great influence which 
 even slight alterations in the amount of atmospheric oxygen might produce on the 
 animal life subjected to this change, and hence Eudiometry (eu5o?, good, eGdia, serene air, 
 and fjiTpeiv, to measure), or the mode of measuring the quality of tlie air, quickly became 
 a new and important branch of chemical analysis. At first sight it appeared not unlikely 
 that the unequal development of animal life on the various parts of the globe, would 
 effect considerable alterations in the composition of the air in different localities ; and 
 this idea was borne out, not only by the well-known fact of the unhealthiness of the 
 air of certain districts, such as crowded towns, marshes, and the like, but also by the 
 earliest determinative experiments, which showed variations in the composition of air 
 of various localities amounting to nearly 10 per cent. Thus Fontana determined the 
 quantity of oxygen contained in air by absorption with nitric oxide, and obtained 
 results showing from 18 to 25 per cent. ; whilst Scheele, on absorbing the oxygen with 
 sulphide of potassium, or by a mixture of sulphur, iron, and water, found from 25 
 to 33 per cent, of that gas present in air. Other experimenters, however , and 
 among them Dalton, Gay-Lussac, Davy, and Boussingault found, on employing other 
 analytical methods, that the amount of the atmospheric oxygen varied but very slightly 
 in different situations, and that the non-accordance of the results formerly obtained 
 was owing to errors of experiment, caused by the use of imperfect methods. The 
 
 
ATMOSPHERE. 43o 
 
 quantity of oxygen found by Dalton in English air was from 207 to 28 per cent., and 
 Gay-Lussac and Humboldt found that Paris air contained from 21 '1 to '20-9 per cent., 
 whilst Davy in London obtained from 20*8 to 21 '1 per cent. ; Thomson in Glasgow, 
 21*1 ; and Kupffer, in Kasan, 21 '1 per cent, of oxygen. Experiments made by Dalton 
 himself on the composition of mountain air, did not tend to confirm his theory as to the 
 diminution of the relative quantity of oxygen at great heights ; and further experience 
 showed that Dalton's views, although theoretically correct for an atmosphere of mixed 
 gases at rest, are not applicable to the air in motion : for Gay-Lussac and Thenard 
 analysed the air which the former savant collected in his celebrated balloon ascent at 
 a li eight of 7000 metres, and they found that the oxygen amounted to 21 '6 per cent, 
 agreeing exactly with an analysis of the air of Paris, made in the same way at the 
 same time, both differing, however, owing to a common error of experiment, from the 
 exact result of later observers. Although from these experiments we can draw the 
 important conclusion that, within certain very small limits, the air has throughout its 
 mass a constant composition as regards oxygen, still the observational errors of these 
 earlier investigators were large, and it was evidently necessary that the composition of 
 the atmosphere should be determined with all the precision that modern science could 
 bestow. The more recent labours of Dumas and Boussingault, Eegnault, Bunsen, and 
 Lewy, have attained this end by help of methods in which the maximum error is 
 reduced to ~o- 
 
 The analysis of air may be conducted in two ways. Either by measuring the 
 volumes of tne.component gases, or by determining their weight. The details of the for- 
 mer, or the eudiometric method, are fully described in the article on ANALYSIS OF GASES, 
 and this is the method adopted, with slight variations, by Eegnault, Bunsen, and 
 Lewy, whilst the determination by weight has been employed by Dumas and Boussin- 
 gault. 
 
 For the purpose of carrying out the analysis of air, these two French chemists 
 [Ann. Ch. Phys. [3] iii. 257], employed an apparatus in which air previously freed 
 from aqueous vapour, carbonic acid, and ammonia, by passing through U-tubes con- 
 taining sulphuric acid and potash, was passed through a weighed tube containing 
 metallic copper kept at a red heat, and then entered an exhausted balloon, the weight 
 of which had been accurately determined. The difference of weight of the tube before 
 and after the experiment, was due to the oxygen ; that of the balloon, to the nitrogen of 
 the air which passed into the apparatus. This process, conducted with every possible 
 precaution, showed the composition of the atmosphere to be : 
 
 Percentage qf oxygen by Weight. 
 
 1841. Small balloon. Large balloon. 
 
 27th April . . . 22-92 22-92 
 
 28th ... 23-03 23-09 
 
 29th ... 23-03 23-04 
 
 22-993 23-016 
 
 or 100 parts by weight of air, are composed of 23 parts of oxygen, and 77 parts of 
 nitrogen. From this composition by weight, the composition by volume of the air can 
 be determined when the specific gravity of the oxygen = o and that of the nitrogen 
 
 23 77 100 
 = n are given: for + = -= . Dumas and Boussingault found, on employing 
 
 the specific gravities as obtained by Berzelius and Dulong, that the sum was not 100 
 but 99-J6 ; hence they concluded that these specific gravities must be incorrect, and 
 determined them again, obtaining o = 1-1057, and n = 0-972, from which the com- 
 position by volume of the atmosphere was found to be 
 ' Oxygen = 20-81 
 Nitrogen = 79-21 
 
 100-02 
 
 The near approximation of these numbers to the truth, has since been proved by the 
 very exact experiments of Eegnault (see Eegnault' s work on Steam, p. 151 ; or Pogg. 
 Ann. Ixxiv. p. 202), who has shown that one litre of air at C. and 076 m. pressure, 
 freed from moisture, carbonic acid, and ammonia, weighs 1-293187 grms., whilst one litre 
 of oxygen, under like circumstances, weighs 1-429802 grms., or has a specific gravity of 
 1-10563, and 1 litre of nitrogen at C. and 0-76, weighs 1-256167 grm., or has a specific 
 gravity of 0'97137. In accordance with these results, Boussingault found in air which 
 he collected in South America, the following percentage volumes of oxygen : 
 
 Air from Santa Fe de Bogota, at a height of 2650 m. above sea- level 20-65 p. c. 0. 
 
 Ibaque 1323 2070 p. c. O. 
 
 Mariquita 518. 2077 p c. O. 
 
 FF 2 
 
436 ATMOSPHERE. 
 
 The eudiometric determinations of Bunsen and Eegnault are on the whole to be 
 preferred to any method of analysis of the air by weight, not only from their greater 
 accuracy, but from the simplicity of the apparatus employed, and the ease with which 
 small samples of air collected at various times and in different localities can thus be 
 analysed. 
 
 Bunsen (Gasometry, p. 71), in a series of analyses of air made on fourteen different 
 days in January and February 1846, amongst which the maximum amount of oxygen 
 was 20'97 per cent, and the minimum 20-84 per cent., found a mean of 20-93 per cent, of 
 oxygen. 
 
 Eegnault (Ann. Ch. Phys. [3] xxxvi. 385) has analysed a very large number 
 of samples of air collected in various quarters of the globe in a uniform manner, 
 according to instructions given by him. The method of analysis employed rarely 
 gave a difference of 0*02 per cent, on the same sample of air. In more than one 
 hundred analyses of air collected in or near Paris, Kegnault found a maximum amount 
 of 20*999 vols. of oxygen, and a minimum of 20-913 or a mean of 20-96. This differ- 
 ence of 0-086 per cent, is, according to Eegnault, too large to be accounted for by ex- 
 perimental errors. 
 
 9 samples from Lyons, Montpelier, Normandy gave 
 
 from . . . 20-918 to 20-966 p.c. of 0. 
 
 30 samples collected in Berlin contained . . . 20-908 20-998 
 10 Madrid ... 20-916 20-982 
 
 23 from Geneva and Chamounix . . . 20'909 20*993 
 
 Of seventeen samples of air collected in Toulon Eoads and other parts of the Medi- 
 terranean, fifteen gave similar results of 20-912 to 20-982 per cent, oxygen, whilst two 
 samples collected from Algiers harbour contained only 20*42 and 20-395 per cent. 
 This abnormal result cannot be accounted for, but a similar phenomenon was observed 
 by Lewy. 
 
 5 samples taken on the voyage from Liverpool to Vera 
 
 Cruz gave 20-918 to 20-965 p. c. of 0. 
 
 2 samples from Ecuador in S. America contained .20-96 
 
 2 the summit of Pichincha, higher than 
 
 Mont Blanc 20-949 to 20-988 
 
 Eleven samples collected in the Asiatic seas from 1848 to 1850, all except two, gave 
 normal results. On the 1st February 1849, the air in the Bay of Bengal contained only 
 20-46 and 20*45 per cent, oxygen, and on the 8th March 1849 the air from above the 
 Ganges, collected during foggy weather, in presence of much decomposing animal 
 matter, temperature 35 C., when cholera was commencing, contained from 20*390 to 
 20-387 per cent, of oxygen. 
 
 Air collected by Captain Sir James Eoss in the Arctic seas gave the normal com- 
 position from 20-86 to 20-94 per cent, oxygen. The conclusion which Eegnault draws 
 from all these determinations, is that the atmosphere shows perceptible, though very 
 small, alterations in the amount of oxygen at different times and in different places. 
 This variation ranges from 20-9 to 21-0 per cent,, but from special unknown causes in 
 tropical countries, the amount of oxygen may sink as low as 20'3 per cent. Bunsen's 
 analyses of the air in Iceland confirm these views. 
 
 Lewy (Ann. Ch. Phys. [3] xxxiv. 1) has also published a series of analyses of air 
 collected from various parts of the globe. The relative amounts of oxygen and nitrogen 
 were determined by Eegnault' s eudiometric process, and the maximum difference be- 
 tween the composition of the same sample of air analysed at different times was Y^,^. 
 The air of Paris contained, in a mean of three experiments, 21*014 per cent, of oxygen, 
 that of Havre 20*888 per cent., whilst that collected on the Atlantic gave 20*961 and 
 21*061 per cent., and in South America, 20-995 and 21*022 per cent, of oxygen. Hence 
 we can positively state that no greater difference exists between the composition of 
 the atmosphere as regards oxygen and nitrogen in different latitudes (some few special 
 cases excepted), than is found in the same place at different times. 
 
 _ Frankland (Chem. Soc. Qu. J. xiii. 22) has lately determined the composition of 
 air collected by himself at different elevations on Mont Blanc, viz. at the Grands 
 Mulcts^ at the summit, and at Chamounix. The conclusion which Frankland draws 
 from his experimental numbers is, that as far as the nitrogen and oxygen are con- 
 cerned, the composition of these samples of air falls within the limits of variation 
 noticed by former experimenters. 
 
 That the air is a mechanical mixture and not a chemical combination of oxygen 
 and nitrogen is seen from the following facts: 1. The amounts of oxygen and nitrogen 
 in the air do not present any simple relation to the combining proportions of. these 
 
 
 
ATMOSPHERE. 
 
 437 
 
 2. On mixing oxygen and nitrogen gases in the 
 > contraction or evolution of heat is observed, and 
 
 elements, and are moreover variable. 
 
 proportion in which they occur in air, no contraction or evol 
 
 the mixture acts in every way as air. 3. When air is dissolved in water, the proportion 
 
 between the oxygen and nitrogen in the dissolved air is quite different from that in 
 
 the undissolved air, this difference occurring in strict accordance with the laws of the 
 
 absorption of gases in liquids (see GASES, ABSORPTION OF). When water is saturated with 
 
 air at any temperature below 30 C., 100 volumes of the dissolved air contain 34-19 vols. 
 
 of oxygen and 65'09 vols. of nitrogen, whilst the undissolved air contains 2T1 per cent. 
 
 of oxygen and 78'9 per cent, of nitrogen. Were the air a chemical combination of 
 
 oxygen and nitrogen, such a separation by solution would be impossible. 
 
 The other constituents of the atmosphere, viz. the aqueous vapour, carbonic acid, 
 ammonia, and decomposing organic matter, alter in amount at various times and in 
 different places, much more considerably than the oxygen and nitrogen. 
 
 The humidity of the air is affected by many circumstances, such as temperature, 
 distance from masses of water, and configuration of the land over which it lies. The 
 amount of aqueous vapour which any volume of air can take up depends entirely upon 
 the temperature of the air, and is represented by the tension and corresponding 
 density of the vapour of water in vacuo for that temperature ; thus at 10 C. the 
 tension of aqueous vapour is 9 '47 mm. of mercury, and the corresponding density 
 0-00000974, or 1 cubic metre of air at 10 C. is saturated when it contains 974 grms. 
 of water in the form of vapour. It seldom happens, however, that the air contains its 
 saturating quantity of moisture, and the amount varies extremely with the conditions 
 before mentioned ; thus, on the coast of the Eed Sea, during a simoon, the air was 
 found to contain only ^ part of the aqueous vapour required to saturate it, whilst in 
 our moist climate, the air is often saturated with watery vapour. The following table 
 shows the relative humidity, i. e. the existing percentage on the saturating quantity, 
 as found by Kamtz in Halle, as a mean of several years' observations : 
 
 Jan. 
 
 Feb. 
 
 March. 
 
 April. 
 
 May. 
 
 June. 
 
 July. 
 
 Aug. 
 
 Sept. 
 
 Oct. 
 
 Nov. 
 
 Dec. 
 
 850 
 
 79-9 
 
 76-4 
 
 71-4 
 
 69-1 
 
 G9-7 
 
 66-5 
 
 61-0 
 
 72-8 
 
 78-9 
 
 85-3 
 
 86'2 
 
 Hence we see that in Halle the air is most humid in December and driest in 
 August. 
 
 The determination of the aqueous vapour contained in the atmosphere may be 
 made, either by leading a known volume of air through weighed tubes containing 
 some hygroscopic substance, as sulphuric acid or chloride of calcium, or by means 
 of hygrometers of various construction, for the description of which the article 
 HYGROMETKY must be consulted. 
 
 The carbonic acid or anhydride contained in the air varies also considerably in 
 amount, though by no means to so large an extent as the aqueous vapour. Many methods 
 are employed for ascertaining the quantity of carbonic acid present in the atmosphere. 
 The most certain method is to absorb the carbonic acid from a known volume of air by 
 passing the air, freed from aqueous vapour and ammonia, through weighed tubes con- 
 taining caustic potash. Saussure (Pogg. Ann. xix. 391), Brunner (Pogg. Ann. 
 xxiv. p. 569), Pettenkofer (Chem. Soc. Qu. J. x. p. 292), Smith (Chem. Soc. Qu. 
 J. xi. p. 196), and Frankland (Chem. Soc. Qu. J. xiii. 27), have all proposed different 
 methods, for the explanation of which we must refer to the original papers. 
 
 From very numerous observations made by Saussure, Brunner, Lewy, and others, it 
 appears that air in the open country contains quantities of carbonic acid varying from 
 
 3 to 10 volumes in 10,000 of air. As an average number, it has been found that 
 
 4 vols. in 10,000 represent the usual composition of the air as regards carbonic acid. 
 In some few peculiar cases, a much larger proportion of carbonic acid has been found 
 (as noticed by Lewy in S. America at Bogota) ; but these abnormal results are ex- 
 plained by local circumstances, as neighbouring volcanic emanations or burning forests. 
 The air collected above the ocean showed a small variation in carbonic acid between 
 day and night ; that collected in the day contained 5'4, whilst that collected during 
 the night contained 3'3 carbonic acid in 10,000 volumes of air. This observation is 
 easily accounted for by the increase of the coefficients of absorption with the diminution 
 of temperature occurring during the night. Air above the land also slightly changes 
 its amount of carbonic acid at various seasons of the year and times of the day, in 
 dependence upon different meteorological alterations, but as yet experiment has'not 
 decided the nature of this dependence. At a certain elevation above the earth's sur- 
 face, the air, according to Saussure and Schlagentweit, contains more carbonic acid than 
 
 F F 3 
 
438 ATMOSPHERE. 
 
 is found in the lower belts of the atmosphere; this increase, which however it 
 not large, probably arises from the decrease of vegetation in the higher atmospheric 
 regions. In the air of crowded towns or of closed inhabited spaces (such as dwelling- 
 rooms, &c.), the carbonic acid often rises to ten times the normal quantity, owing to in- 
 efficient ventilation. 
 
 Although the relative amount of 4 vols. of carbonic acid in 10,000 vols. of air ap- 
 pears to be a very small one, yet the absolute quantity of carbon thus contained in the 
 atmosphere is very large, exceeding indeed all that is contained on the earth's surface in 
 the solid form, in the bodies of plants and animals, and that found under the earth's 
 solid crust in the coal formations. The question of change in the composition of the 
 earth's atmosphere as regards carbonic acid is one of vital interest to all forms of 
 terrestrial life : for whilst forming the staple nutriment of the vegetable world, car- 
 bonic acid, when present in certain quantities, acts as a violent poison on the higher 
 orders of animal life ; nor is the limit at which this gas begins to be hurtful to the 
 animal, very far removed from the quantity which at present exists in the atmo- 
 sphere : for we find that Leblanc and Peclet assign a limit of five in 1000 (ten times 
 the normal quantity), whilst Eeid and Arnott give a much lower limit to the non- 
 injurious effect of this gas. Whether the atmosphere is now slowly undergoing, or 
 has in past ages undergone, any perceptible change in the amount of its carbonic acid, 
 is a question to which, owing to the absence of certain and accurate data, we are as yet" 
 unable to give any very satisfactory answer. We do, however, know that there are a 
 great number of causes continually at work, some of which tend to increase the amount 
 of atmospheric carbonic acid, whilst there are others which tend to effect a diminution 
 in this constituent. Whether the resultant of these various counteracting influences is 
 such as to keep, during future ages,* the carbonic acid exactly at the present amount, it 
 is, with our present knowledge, impossible to say ; but from the remarks which follow, 
 it will be seen that if any alteration occur, it must proceed with extreme slowness. 
 
 The principal causes which tend to increase the atmospheric carbonic acid are : 
 (1) The respiration of animals. (2) Combustion of vegetable carbonised material. 
 (3) Exhalations of carbonic acid caused by volcanic and other intra-terrestrial 
 agencies. It would appear that the quantity of carbonic acid escaping from volcanic 
 vents, mineral springs, and other inorganic sources into the atmosphere is much 
 larger than that produced by the two causes first named. According to the calcula- 
 tions of Poggendorff (naturally but very rude approximations to the truth), it seems 
 that, taking the amount of carbonic acid evolved by volcanic action to be ten times 
 larger than that given off by every kind of combustion of carbonised material, the 
 quantity of carbonic acid at present contained in the atmosphere would be doubled in 
 386 years, supposing, of course, that no causes of diminution of were acting. That 
 such causes of diminution are, however, continually at work we know. They consist 
 mainly in (1) the decomposition of carbonic acid, i. e. reduction of carbon and regenera- 
 tion of oxygen, which living vegetables effect in sunlight. (2) The fixation of carbonic 
 acid as carbonate of lime by the vital action of certain animalculse, giving rise to 
 coral reefs and islands, and the whole of the vast limestone deposits. (3) The 
 fixation of carbonic acid by inorganic chemical processes. 
 
 The immense extent to which these actions, particularly the second one, have gone 
 and are still going on, appears to justify the opinion that if any change in the amount 
 of the atmospheric carbonic acid occur at all, it is more probably a diminution than 
 an increase. Any conclusions which we can draw from geological facts, seem rather to 
 support this opinion : for it is more likely that the air contained a larger amount of 
 carbonic acid during the deposition of the enormous carboniferous system when the 
 vegetation must have been so luxuriant and profuse, and when few, if any, air-breathing 
 animals existed, than less than at present. Still, we have no right positively to 
 assume that the air at the time of the deposition of the coal and limestone contained 
 more carbonic acid than now : for we know nothing of the length of time during which 
 these formations were in progress. 
 
 From the foregoing remarks, it is seen that a continual circulation of the atmospheric 
 carbon takes place ; the animal gives off the waste portion of its body mainly as car- 
 bonic acid, and thus deteriorates the atmosphere, which would soon become unfit for 
 his further use, if the vegetable world did not absorb the poisonous gas, at once 
 ret'iiuinp: the carbon in the solid form, fit for the subsequent nourishment of the animal, 
 and exhaling the oxygen wherewith the higher organism again removes his spent 
 materials. 
 
 Having described the causes effecting possible variation of the atmospheric carbonic 
 acid, it is almost needless to consider any change which the oxygen may undergo, for 
 the atmosphere becomes unfit for the sustenance of animal life from the presence of a 
 small quantity of carbonic noid, long before the oxygen is materially diminished. If, 
 however, the carbonic ut-id is slowly decreasing, it nuiy be interesting to inquire how 
 
ATMOSPHERE. 439 
 
 long our supply of oxygen will last us. Such a speculation has been answered, as satis- 
 factorily as the circumstances admit of, by Dumas and Boussingault. These chemists 
 calculated that if the whole of the earth's atmosphere were put into a balloon and sus- 
 pended from one end of a balance, it would require 581,000 cubes of copper, each having 
 aside of 1 kilometre (1093 English yards) in length, to be suspended at the other end 
 to equalise the balance. Of this total weight, the oxygen would be represented by 
 134,000 cubes. Assuming, from the best data, that a man consumes a kilogramme of 
 oxygen per day, taking the population of the earth to be 1000 millions, and supposing 
 that the oxygen .taken up by animals and by putrefactive processes is four times as large 
 as that consumed by human beings, and supposing further, that the oxygen given off 
 by plants only covers the expenditure of oxygen effected by other causes not mentioned, 
 it appears, even in this exaggerated case, that an amount of oxygen three times as large 
 as that consumed in one century by the whole number of animals existing on the earth, 
 is represented by 15 or 16 of the copper cubes, each having a side of 1 kilometre in 
 length, or the alteration effected in a century is less than ^ of the total quantity of oxy- 
 gen, and is therefore altogether inappreciable by our most exact determinative methods. 
 (See Dumas and Boussingault (1841) Ann. Ch. Phys. [3] iii. 257, 288.) 
 
 As regards the ammonia and the organic impiirities contained in the atmo- 
 sphere, we still labour under the disadvantage of insufficient experimental data. The 
 great difficulty in the estimation of these constituents, lies in the very minute quantities 
 which are contained in the atmosphere. This difficulty is seen when we compare some 
 of the statements put forward of the amount of atmospheric ammonia ; thus Ho rs ford 
 (Ann. Ch. Pharm. Ixxiv. 243), found in 1 million parts of air, 47*6 parts of ammonia, 
 whilst Bineau (Ann. Ch. Phys. xlii. p. 462) found in the same quantity of air, from 
 0'04 to O'l part of ammonia. Between these extremes, we have numerous experiments 
 in which every variation in the quantity of atmospheric ammonia has been found. Al- 
 though, from the great differences in the numerical results (maximum 135 ; minimum 
 O'l parts of carbonate of ammonia), probably arising, partly from errors of analysis and 
 partly from real variations in the contained quantity, it is impossible to fix upon any 
 number as giving the average composition, still it is certain that the atmosphere 
 always contains ammoniacal salts, and that rain (the first portions more than the latter 
 portions), hail, snow, and dew, all contain appreciable quantities of ammonia. 
 
 The atmospheric ammonia plays a very important part in vegetation : for it is mainly 
 if not altogether, from the ammoniacal salts contained in the air, that plants obtain 
 the nitrogen which they require for the formation of seed and other essential parts of 
 their structure. Whether plants are at all able to assimilate the free nitrogen of the 
 atmosphere, must, in spite of the numerous researches on the subject, be considered 
 doubtful. George Ville has for some time asserted, founding his assertion on a large 
 number of elaborate experiments, that plants can absorb and assimilate the free atmo- 
 spheric nitrogen. Boussingault, on the contrary, from his own extensive investigations, 
 denies Ville' s conclusions, affirming that it is from nitrogenous compounds alone that 
 plants can assimilate the nitrogen. The commission of the French Academy, which 
 was deputed to examine the question under the direction of Chevreul, reported in 
 Ville's favour, although some doubt as to the estimation of the ammonia contained in 
 the distilled water used, was expressed. Still more lately Lawes, Gilbert, and Pugh, 
 have investigated the subject with great care, and find that plants growing in an 
 atmosphere and on a soil free from ammonia or combined nitrogen in other forms, 
 do not contain more nitrogen than the seeds from which they grow. In the state of 
 uncertainty in which such contradictory statements leave us, we may, however, be certain 
 of one fact in which all the experiments agree, namely, that whether or not plants can 
 assimilate small quantities <5f free nitrogen, it appears that plants growing in air 
 perfectly free from ammonia, do not flourish to anything like the same extent as plants 
 living in an ammoniacal atmosphere. 
 
 Concerning the remaining constituents, and especially the organic putrescent matters, 
 our present knowledge is even less satisfactory or positive than is the case with the 
 ammonia. Within a very recent period, we were unacquainted with any method for 
 determining the presence of organic putrescent matters ; and even the very important 
 and ingenious method lately proposed by Dr. E. Angus Smith (Chem. Soc. Qu. J. 
 xi. p. 196) requires much extension and general application before we can arrive at 
 a knowledge of the exact qualitative distribution of the organic impurities. Smith's 
 method (for the details of which we must refer to the paper), depends upon the 
 reducing action which solid, liquid or gaseous organic putrescent matter effects on per- 
 manganate of potassium. The strength of the test-solution is determined by adding 
 it to a solution of sugar of known composition, until the colour of the permanganate 
 remains permanent ; and the same reaction performed with the air under examination, 
 shows the quantity of contained organic matter. In this way, Smith has detectc-d great 
 
 FF 4 
 
440 ATOMIC VOLUME. 
 
 differences between the air of various localities. The air from high country ground 
 was found to contain 1 grain of organic matter in 200,000 cubic inches of air, whilst 
 the air from a cesspool contained the same quantity of organic matter in 60 cubic 
 inches of air. In a sanitary, as well as in a purely scientific point of view, it is diffi- 
 cult to over-estimate the importance of this simple method for determining the organic 
 impurities which air contains ; and if future research confirm its applicability to all 
 cases, it will prove an invaluable instrument in the hands of the physician and the 
 sanitary reformer. 
 
 Besides the constituents already mentioned, air contains minute quantities of 
 nitrates, hydrocarbons, sulphurous and sulphuric acids, and according to some 
 chemists, iodine, but this has been lately denied. Ozone also occurs in the atmo- 
 sphere in very small amounts, varying, however, extremely with the situation and 
 meteorological conditions of the place. (See OZONE.) 
 
 The atmosphere of the ocean, as well as of the masses of fresh water occurring on 
 the earth's surface, is subject to the same changes from the existence of animal and 
 vegetable life, as the earth's gaseous atmosphere. The relative proportion between the 
 gases dissolved in the water is fixed in accordance with the law of absorption, and 
 many important and interesting conclusions, such as the relative increase of dissolved 
 oxygen, or diminution of temperature, enabling mammalia to live in the polar but not 
 in the tropical seas, can be drawn from an application of these laws to the atmosphere 
 of the sea. The equilibrium between the constituents of the dissolved atmosphere 
 kept up by animal and vegetable life, is well illustrated by the vivaria now so common, 
 which were first introduced by Mr. Warington. 
 
 The air of towns and close-inhabited spaces, becomes, as has been stated, often 
 overcharged with carbonic acid and other impurities. The amount of carbonic acid 
 present in dwelling-rooms, &c., has been made the subject of experiment byLeblanc 
 (Ann. Ch. Phys. [3] v. 223; xxvii. 373), Pettenkofer (Chem. Soc. Q,u. J. x. 292) ; 
 Roscoe (Chem. Soc. Q-u. J. x.) ; and Smith (Chem. Soc. Qu. J. xi 196). The main 
 results may be stated to be : (1) that in rooms which are not thoroughly ventilated, the 
 amount of carbonic acid may rise from 1 to 7 volumes in 1000 of air ; (2) that in well 
 ventilated rooms, the amount of carbonic acid should not rise above 0'8 in 1000; 
 (3) that in ordinary dwellings, or even in school- or barrack-rooms, the carbonic acid is 
 diffused uniformly throughout the space, in whatever parts of the room the exit for 
 deteriorated air is placed, though in the exaggerated -case of crowded theatres, the 
 air at the highest part of the building was found to contain more carbonic acid than 
 the air at the level of the stage. For other interesting details, we must refer to the 
 original papers, or to the article on VENTILATION. H. E. E. 
 
 ATOMIC VOLUME. Specific volume; Equivalent volume; Molecular volume. 
 The atomic or specific volume of a body is the space occupied by a quantity of 
 it proportional to its atomic weight, and is therefore expressed by the quotient of the 
 atomic weight divided by the weight of a unit- volume, that is by the specific gravity : 
 
 ... , atomic weight 
 
 Atomic volume = ^- -s_ - 
 
 specific gravity 
 
 It must not, however be supposed that the atomic volumes represent the relative 
 volumes of the actual material atoms of different bodies. For, regarding any sub- 
 stance, solid, liquid, or gaseous, as an aggregate of material particles capable of 
 moving amongst themselves, it is impossible to suppose these particles to be in actual 
 contact and to fill up the entire volume of the body ; we must suppose them to be 
 separated by certain intervals : consequently the specific gravity, and therefore also 
 the specific volume of the. body, will depend, partly on the relative weights of these 
 atoms, partly on the number of them contained in a given space, and therefore on the 
 magnitude of the interstitial spaces. Unless, therefore, the spaces are either infinitely 
 small in comparison with the magnitude of the atoms themselves, or bear the same 
 proportion thereto in all bodies, it is impossible to determine the relative volumes of 
 the actual material atoms: for we have no means of ascertaining the proportion 
 between the size of the atoms and of the intervening spaces in each particular case. 
 The atomic volume of bodies must therefore be understood, as the spaces occupied by 
 aggregates of atoms (including the interstitial spaces), whose weights are proportional 
 to the atomic weights of the bodies. 
 
 As the atomic weights, or multiples thereof, represent the proportions in which 
 bodies combine by weight, so likewise do the atomic volumes or multiples thereof 
 indicate the proportions in which they unite by volume, thus : the atomic volume of 
 1 97 1 OR 
 
 iodine being ^ = 257, and that of silver = = 10-2, we infer that 257 vols. 
 iodine unite with 10'2 vols. silver to form iodide of silver, Agl. 
 
ATOMIC VOLUME. 441 
 
 The numbers representing the atomic volumes of bodies vary according to the units 
 of atomic weight and specific gravity chosen, and according to the particular values 
 assigned to the atomic weights. Thus, if the atomic weight of hydrogen be equal to 1, 
 that of chlorine = 35 -5, and of sulphur = 32, the atomic weight of hydrochloric acid 
 (HC1) wiU be 36-5, and that of sulphydric acid (H 2 S) = 34. Now the specific gravity 
 of hydrochloric acid gas referred to air as unity is 1-264, and that of sulphydric acid 
 is 1-177. Hence we have : 
 
 Atomic volume of HC1 = r-^J = 14-44 
 1-264 
 
 If, on the other hand, we adopt hydrogen as the standard of specific gravity for gases, 
 that of hydrochloric acid is 18-25, and that of sulphydric acid is 17, in each case 
 half the atomic weight. On this hypothesis, therefore, the atomic volumes of both 
 gases are expressed by the number 2. Again, if common ether be represented by the 
 formula C 4 H 10 O [C = 12, H = 1, O = 16], its atomic weight is 74; and, its specific 
 gravity in the gaseous state being 37 (referred to hydrogen), its atomic volume in 
 
 that state is -^= 2, and in the liquid state (specific gravity at referred to water), 
 07 
 
 74 
 its atomic volume is 7 r^^ = 100-41. But if ether be represented by the formula 
 
 U' I of 
 
 C 4 H b O [C = 6, H = 1, = 8], then its atomic volume in the gaseous state will be 
 
 O fj OT 
 
 '- = 1, and in the liquid state -^-^^ = 50-205. The atomic volumes of gases and 
 
 of (J'iof 
 
 vapours are calculated from the specific gravities referred either to hydrogen or to 
 atmospheric air ; those of solids and liquids from the specific gravities referred to water 
 as unity. 
 
 Atomic Volumes of Gases. 
 
 According to the system of atomic weights adopted in this work, equal volumes of 
 different elementary gases are supposed to contain, for the most part, equal numbers 
 of atoms of their respective elements, so that the atomic weight of each body in the 
 gaseous state is the weight of a volume of the gas equal to that of a quantity of hydro- 
 gen whose weight is taken as unity ; in other words, the atomic weights of the simple 
 gases are expressed by the same numbers as their specific gravities referred to hydro- 
 gen as unity. This is sometimes expressed by saying that an atom of each elementary- 
 gas occupies one volume. The only exceptions to this law are presented by phosphorus 
 and arsenic, whose densities in the gaseous state are double of what they should be if 
 they followed the law ; and by selenium and tellurium, whose vapour-densities have not 
 yet been ascertained with certainty. Sulphur- vapour was formerly supposed to have 
 a density three times as great as that which the general law just stated requires, but 
 recent experiments have shown that it conforms to the general law. 
 
 The atoms or molecules of compound bodies in the gaseous state occupy, for the 
 most part, twice the volume of an atom of hydrogen or other simple gas ; in other 
 words, the number of molecules of a compound gas contained in a given space is half 
 the number of atoms of hydrogen which would be included in that same space. Con- 
 sequently, the specific gravity of a compound gas or vapour referred to hydrogen as 
 unity is equal to half the atomic weight. Thus, the atomic weight of hydrochloric 
 acid (HC1) is 36*5, and its specific gravity referred to hydrogen is 18*25; the atomic 
 weight of ammonia (NH 3 ) is 17, and its specific gravity referred to hydrogen is 8 -5. 
 (For the further development of this law, and for certain exceptions to it, real and 
 apparent, see the article ATOMIC WEIGHTS.) 
 
 The mode of stating these laws of gaseous atomic volume, must of course be modified 
 according to the system of atomic weights chosen. On that which has hitherto been 
 most generally adopted (H =1,0 = 8, $=16, &c.), some of the elementary gases, 
 viz. chlorine, iodine, bromine, nitrogen, and mercury are supposed to have atomic 
 volumes equal to that of hydrogen, while oxygen, sulphur, phosphorus, and arsenic 
 have atomic volumes only half as great. The former are generally called two-volume 
 gases, and the latter one-volume gases, the volume of oxygen being taken as the unit. 
 On the same system, the molecules of most compound bodies in the gaseous state are 
 said to occupy four volumes. 
 
442 
 
 ATOMIC VOLUME. 
 
 Atomic Volumes of Liquids and Solids. 
 
 1. Of Elementary Bodies. The following table contains the atomic volumes of 
 those solid and liquid elements whose densities have been determined with accuracy. 
 The numbers in the third column are the quotients of the atomic weights divided by the 
 specific gravities referred to water as unity : 
 
 Substance. 
 
 Atomic 
 weight. 
 
 Atomic 
 volume. 
 
 Specific gravity (water = 1). 
 
 Aluminium 
 
 1375 
 
 5-3 
 
 2-5 2-67, Wohler; 2'67, Deville. 
 
 Antimony 
 
 120-3 
 
 17'9 
 
 6*72, Marchand and Scheerer; Kopp. 
 
 Arsenic . 
 
 75 
 
 13-3 
 
 5-63, Karsten; 5'67, Herapath. 
 
 Bismuth 
 
 210 
 
 21-2 
 
 9-80, Marchand and Scheerer ; 978, Kopp. 
 
 Bromine 
 
 80 
 
 25-8 
 
 Liquid: 3 -19, Pierre; 2-99, Lowig. 
 
 Cadmium 
 
 56 
 
 6-5 
 
 8'69, Stromeyer ; 8'45, Kopp. 
 
 Calcium 
 
 20 
 
 12-6 
 
 1-58, Bunsen. 
 
 
 12 
 
 ( 3-4 
 
 Diamond: 3 -52, Brisson. 
 
 Carbon . . . 
 
 
 i 5-2 
 
 Graphite: 2 '32, Karsten ; 2'27, Eegnault. 
 
 Chlorine 
 
 35-5 
 
 26-7 
 
 Liquid: 1'33, Faraday. 
 
 Chromium 
 
 26-2 
 
 3-8 
 
 7 '01, Bunsen and Frankland. 
 
 Cobalt . 
 
 29-5 
 
 3-5 
 
 8-49, Brunner ; 8*51, Berzelius. 
 
 Copper . 
 
 31-7 
 
 3-6 
 
 8-95, Marchand and Scheerer ; 8'93, Kopp. 
 
 Glucinum 
 
 4-7 
 
 2-2 
 
 2-1, Debray. 
 
 Gold . 
 
 196 
 
 10-2 
 
 19-34, G. Eose; 19'26, Brisson. 
 
 Iodine . 
 
 127 
 
 25-7 
 
 4-95, Gay-Lussac. 
 
 Iridium . 
 
 99 
 
 4-5 
 
 21-80, Hare. 
 
 Iron 
 
 28 
 
 3-6 
 
 7-84, Broling; 779, Karsten 
 
 Lead . 
 
 103-6 
 
 9-2 
 
 11-39, Karsten; 11 '33, Kopp. 
 
 Lithium 
 
 7 
 
 11-9 
 
 0*59, Buusen. 
 
 Magnesium . 
 
 12 
 
 6-9 
 
 1-74, Bunsen; 1 '70. Kopp. 
 
 Manganese 
 
 27-6 
 
 3-5 
 
 8-03, Bachmann ; 8*01, John. 
 
 Mercury 
 
 100 
 
 7'4 
 
 Liquid : 13'60, Eegnault, Kopp. 
 
 Molybdenum . 
 
 46 
 
 5-3 
 
 8-628-64, Buchholz. 
 
 Nickel . 
 
 29-5 
 
 3-4 
 
 8-60, Brunner; 8'82, Tupputi. 
 
 Palladium 
 
 53 
 
 4-6 
 
 11-80, Wollaston. 
 
 Phosphorus . 
 
 31 
 
 (16-8 
 \ 15-8 
 
 Yellow: 1-84, Schrotter; 1'83, Kopp. 
 Bed: 1-96, Schrotter. 
 
 Platinum 
 
 99 
 
 4-6 
 
 21-5, Wollaston, Berzelius. 
 
 Potassium 
 
 39-2 
 
 45-6 
 
 0*86, Gay-Lussac and Thenard. 
 
 Rhodium 
 
 52 
 
 4-7 
 
 11-0, Wollaston; 11-2, Cloud. 
 
 Selenium 
 
 79 
 
 (18-4 
 j 16-4 
 
 Amorphous: 4-28, Schaffgotsch. 
 Granular : 4'80, Schaffgotsch. 
 
 Silicon . 
 
 28 
 
 11-2 
 
 Graphito'idal : 2'49, Wohler. 
 
 Silver . 
 
 108 
 
 10-2 
 
 10-4, Karsten, 10'57, G. Eose. 
 
 Sodium . 
 
 23 
 
 23-7 
 
 0'97, Gay-Lussac and Thenard. 
 
 Strontium 
 
 43'8 
 
 17-2 
 
 2-54, Bunsen. 
 
 Sulphur 
 
 32 
 
 515-2 
 }l6'2 
 
 Trimetric : 2-07, Marchand and Scheerer, Kopp. 
 Monoclinic: 1'98, Marchand and Scheerer. 
 
 Tellurium 
 
 128 
 
 20-6 
 
 6-24, Berzelius; 6'18, Lowe. 
 
 Tin ... 
 
 118 
 
 16-2 
 
 7'29, Karsten; 7 '30, Kopp. 
 
 Tungsten 
 
 92 
 
 5-3 
 
 17'2, Allen and Aiken; 17'5 18'3, Wohler. 
 
 Uranium 
 
 60 
 
 3-3 
 
 18-4, Peligot. 
 
 Ziiic 
 
 32-5 
 
 4-6 
 
 7'13, Kopp; 7-1 7'2, BoUey. 
 
 The numbers in the third column of this table, do not exhibit the simplicity of re- 
 lation which exists between the atomic volumes of gaseous bodies. There are, indeed, 
 several causes which interfere with the existence, or at least with the observation, of 
 such simple relations between the atomic volumes of solid and liquid elements. In 
 the first place, the densities of three of them, viz. mercury, bromine, and chlorine, are 
 such as belong to them in the liquid state, whereas the densities assigned to all tho 
 others have been determined in the solid state. In solids, moreover, the density is 
 greatly affected by the state of aggregation, whether crystalline or amorphous, and in 
 dimorphous bodies, each form has a density peculiar to itself. Further, as solids ami 
 
ATOMIC VOLUME. 
 
 443 
 
 liquids are variously affected by heat, each having a peculiar rate of expansion, and 
 that rate being different at different temperatures, it is not to be expected that their 
 atomic volumes should exhibit simple relations, unless they are compared at tempe- 
 ratures at which they are similarly affected by heat. Even gases are found to exhibit 
 abnormal atomic volumes if compared at temperatures too near the points at which 
 they pass into the liquid state. In liquids, the simplest relations of atomic volume are 
 found at those temperatures for which the tensions of the vapours are equal (Kopp) ; 
 and in solids, the melting points are most probably the comparable temperatures. 
 Now the specific gravities of most of the solid elements in the preceding table, have 
 been determined at mean temperatures (as at 15-5 C.), which, in the case of potassium, 
 sodium, phosphorus, and a few others, do not differ greatly from the melting points, 
 but in other cases, as with gold, platinum, iron, &c., are removed from the melting 
 points by very long intervals. In spite, however, of these causes of divergence, the 
 atomic volumes of certain analogous elements are very nearly equal to each other : viz. 
 those of selenium and sulphur ; of chromium, iron, cobalt, copper, manganese and 
 nickel; of molybdenum and tungsten ; of iridium, platinum, palladium and rhodium; 
 and of gold and silver. 
 
 2. Of Liquid Compounds. The relations between the atomic volumes of liquids, 
 have been investigated chiefly by H. Kopp (Ann. Ch. Phann. xcvi. 153, 303, c. 19). 
 The atomic volumes of liquids, as already observed, are comparable only at temperatures 
 for which the tensions of their vapours are equal, as at the boiling points. If the 
 atomic weights are compared with the densities at equal temperatures, no regular re- 
 lations can be perceived ; but when the same comparison is made at the boiling points 
 of the respective liquids, several remarkable laws become apparent. The density of a 
 liquid at its boiling point cannot be ascertained by direct experiment ; but when the 
 density at any one point, say at 15 '5 C., has been ascertained, and the rate of ex- 
 pansion is also known, the density at the boiling point may be calculated. (See 
 EXPANSION.) 
 
 Table A. contains Kopp's determinations of the atomic volumes of several liquids 
 containing carbon, hydrogen, and oxygen, at their boiling points. The atomic weights 
 are those of the hydrogen scale. The calculated atomic volumes in the fourth column 
 are determined by a method to be presently described ; the observed atomic volumes 
 are the quotients of the atomic weights divided by the specific gravities at the boiling 
 referred to water as unity. 
 
 TABLE A. 
 Atomic Volumes of Liquids containing Carbon, Hydrogen, and Oxygen. 
 
 Substance. 
 
 Formula. 
 
 Atomic 
 Weight. 
 
 Atomic Volume at the Boiling Point. 
 
 Calculated. 
 
 Observed. 
 
 
 ^Benzene .... 
 
 C 6 H 6 
 
 78 
 
 99-0 
 
 96-0... 99-7 at 80 C. 
 
 
 Cymene . . 
 
 C'H 14 
 
 134 
 
 187-0 
 
 183-5.. .185-2 175 
 
 . 
 
 Naphthalin 
 
 C 10 H 8 
 
 128 
 
 154-0 
 
 149-2 . . 218 
 
 
 Aldehyde . 
 
 C 2 H'0 
 
 44 
 
 56-2 
 
 56-0... 56-9 21 
 
 
 Valeraldehyde . . 
 Bitter almond oil . 
 
 C 5 H 10 
 C 7 H 6 
 
 86 
 106 
 
 122-2 
 122-2 
 
 117-3.. .120-3 101 
 118-4 . . 179 
 
 H 
 
 Cuminol 
 
 C 10 H 6 
 
 148 
 
 188-2 
 
 189-2 . . 236 
 
 
 Tetryl . . . 
 
 C 8 H 16 
 
 114 
 
 187-0 
 
 184-5. ..186-8 108 
 
 
 -Acetone .... 
 
 C 3 H e O 
 
 58 
 
 78-2 
 
 77-3... 77-6 66 
 
 
 rWater .... 
 
 H 2 
 
 18 
 
 18-8 
 
 18-8 . . 100 
 
 
 Wood-spirit . 
 
 CH 4 
 
 32 
 
 40-8 
 
 41-9... 42-2 59 
 
 
 Alcohol .... 
 
 C 2 H 6 
 
 46 
 
 62-8 
 
 61-8... 62-5 78 
 
 
 Amylic alcohol 
 
 C 5 H' 2 
 
 88 
 
 128-8 
 
 123-6.. .124-4 135 
 
 O 
 
 Phenylic alcohol 
 
 C 6 H fi O 
 
 94 
 
 106-8 
 
 103-6. ..104-0 194 
 
 i 
 
 Benzylic alcohol 
 
 C 7 H 8 
 
 108 
 
 128-8 
 
 123-7 . . 213 
 
 HH 
 
 Formic acid . 
 
 CH 2 2 
 
 46 
 
 42-0 
 
 40-9... 41:8 99 
 
 A 
 
 Acetic acid 
 
 C 2 H 4 O a 
 
 60 
 
 64-0 
 
 63-5... 63-8 118 
 
 H* 
 
 Propionic acid 
 
 C 3 H G 2 
 
 74 
 
 86-0 
 
 85-4 . . 137 
 
 
 Butyric acid . 
 
 C'H 8 2 
 
 88 
 
 108-0 
 
 106-4.. .107-8 156 
 
 
 Valerianic acid 
 
 C 5 H'0 2 
 
 102 
 
 130-0 
 
 130-2.. .131-2 175 
 
 
 .Benzoic acid . 
 
 C 7 1L G 2 
 
 122 
 
 130-0 
 
 126-9 . . 253 
 
444 
 
 ATOMIC VOLUME. 
 
 TABLE A (continued'). 
 
 Substance. 
 
 Formula. 
 
 Atomic 
 Weight. 
 
 Atomic Volume at the Boiling Point. 
 
 Calculated. 
 
 Observed. 
 
 
 'Ethylic ether . 
 
 C 4 H 10 
 
 74 
 
 106-8 
 
 105-6.. .106-4 at 34 C. 
 
 
 Acetic anhydride . 
 
 C 4 H 6 3 
 
 102 
 
 109-2 
 
 109-9.. .110-1 138 
 
 
 Formate of methyl 
 
 C 2 H 4 2 
 
 60 
 
 64-0 
 
 63-4 . . 36 
 
 
 Acetate of methyl . 
 
 C 3 H 6 2 
 
 74 
 
 86-0 
 
 83-7... 85-8 55 
 
 
 Formate of ethyl . 
 
 C 3 H 6 0- 
 
 74 
 
 860 
 
 84-9... 85-7 55 
 
 
 Acetate of ethyl 
 
 C 4 H 8 2 
 
 88 
 
 108-0 
 
 107-4. ..107-8 74 
 
 
 Butyrate of methyl 
 
 C 5 H 10 2 
 
 102 
 
 130-0 
 
 125-7. ..127-3 93 
 
 d 
 
 Propionate of ethyl 
 
 C 5 H 10 
 
 102 
 
 130-0 
 
 125-8 . . ,,93 
 
 w" 
 
 Valerate of methyl . 
 
 C 6 H-0 2 
 
 116 
 
 152-0 
 
 148-7. ..149-6 112 
 
 
 Butyrate of ethyl . 
 
 C 6 H 12 2 
 
 116 
 
 152-0 
 
 149-1. ..149-4 112 
 
 o> 
 
 Acetate of tetryl 
 
 C 6 H 12 2 
 
 116 
 
 152-0 
 
 149-3 . . 112 
 
 J5 
 
 Formate of amyl 
 
 C 6 H 12 2 
 
 116 
 
 152-0 
 
 149-4.. .150-2 112 
 
 H 
 
 Valerate of ethyl . 
 
 C 7 H 14 2 
 
 130 
 
 174-0 
 
 173-5.. .173-6 131 
 
 
 Acetate of amyl 
 
 C 7 H 14 2 
 
 130 
 
 174-0 
 
 173-3. ..175-5 131 
 
 
 Valerate of amyl . 
 
 C 10 H 20 2 
 
 172 
 
 240-0 
 
 244-1 . . 188 
 
 
 Benzoate of methyl 
 
 C 8 H 8 2 
 
 136 
 
 152-0 
 
 148-5. ..150-3 190 
 
 
 Benzoate of ethyl . 
 
 C 9 H'0 2 
 
 150 
 
 1740 
 
 172-4.. .174-8 209 
 
 
 Benzoate of amyl . 
 
 C 12 H'0 2 
 
 192 
 
 240-0 
 
 247-7 . . 266 
 
 
 ^Cinnamate of ethyl 
 
 C"H 12 2 
 
 176 
 
 207-0 
 
 211-3 . . 260 
 
 O ''Acid salicylate of methyl 
 txj | Carbonate of ethyl . 
 W, j Oxalate of methyl . 
 < Oxalate of ethyl . 
 
 C 8 H 8 3 
 C*H 10 S 
 C'H'O 4 
 C 6 H'0 4 
 
 152 
 118 
 118 
 146 
 
 159-8 
 137-8 
 117-0 
 161-0 
 
 156-2. ..157-0 223 
 138-8.. .139-4 126 
 116-3 . . 162 
 166-8.. .167-1 186 
 
 ^ 1 Succinate of ethyl . 
 
 C 8 H I4 4 
 
 174 
 
 205-0 
 
 209-0 . . 217 
 
 A comparison of the numbers in this table, leads to the following results : 
 
 1. Differences of atomic volume are in numerous instances 'proportional to the dif- 
 ferences between the corresponding chemical formula. Thus, liquids whose formulae 
 'differ by n . CH 2 , differ in atomic volume by n . 22 ; for example, the atomic volumes of 
 formate of methyl, C 2 H 4 2 , and butyrate of ethyl, C 6 IF 2 2 , differ by nearly 4 x 22. 
 Acetate of ethyl, C'lPO 2 and butyrate of methyl, C 5 H I0 2 . whose formulae differ by 
 CH 2 , differ in atomic volume by nearly 22. The same law holds good with respect to 
 liquids containing sulphur, chlorine, iodine, bromine, and nitrogen (see Tables B, C, 
 D). Again, by comparing the atomic volumes of analogous chlorine and bromine 
 compounds, it is found that the substitution of 1, 2, or 3 atoms of bromine for an 
 equivalent quantity of chlorine, increases the atomic volume of a compound by once, 
 twice, or three times 5. This will be seen by comparing the atomic volumes of PBr 3 
 and PCI 3 ; C 2 H 5 Br and C 2 H 5 C1, &c. (Table C.) 
 
 P 2 TT 3 O 
 The atomic volume of acetic acid, ^ [ is 
 
 formate of methyl, QJJ| is 63 -4 ; the atomic volume of butyric acid, I is 
 
 2. Isomeric liquids belonging to the same chemical type have equal atomic volumes. 
 
 between 6 3 -5 and 6 3 -8 ; that of 
 
 C 4 H 7 0] 
 H 
 
 between 106-4 and 107'8; that of acetate of ethyl, ^"^JJ [ is between 107'4 and 
 107-8. 
 
 3. In liquids of the same chemical type, the replacement of hydrogen by an equivalent 
 quantity of oxygen (that is to say, of 1 pt. of hydrogen by 8 pts of oxygen), makes but 
 a slight alteration in the atomic volume. This may be seen by comparing the atomic 
 volumes of alcohol, C 2 H 6 0, and acetic acid, C 2 H 4 2 ; of ether, C 4 H 10 0, acetate of ethyl, 
 C 4 H 8 2 , and anhydrous acetic acid, C 4 H 6 3 ; of cymene, C 10 H' 4 , and cuminol, W H W O. 
 The alteration caused by the substitution of for H 2 is always an increase. 
 
 4. In liquids of the same chemical type, the replacement of 2 at. H by 1 at C (1 pt. 
 by weight of hydrogen by 6 parts of carbon) makes no alteration in the atomic volume. 
 Such, for example, is the case with benzoate of ethyl, C 5 H I0 2 , and Valerate of 
 ethyl, C 7 H I4 2 , and with the corresponding benzoates and valerates in general; also 
 
ATOMIC VOLUME. 445 
 
 with bitter-almond oil, C 7 H 6 0, and valeraldehyde, C 5 H 10 ; also with phenylic 
 alcohol, CPTL e O, and vinic ether, C 4 H 10 0. 
 
 In liquids belonging to different types, the same relations are not found to hold 
 good. Moreover the types within which these relations are observed, are precisely 
 thote of Gerhardt's classification (see CLASSIFICATION). Further, when liquid com- 
 pounds are represented by rational formulce founded on these types, their atomic 
 volumes may be calculated from certain fundamental values of the atomic volumes of 
 the elements, on the supposition that the atomic volume of a liquid compound is equal 
 to the sum of the atomic volumes of its constituent elements. In this manner the 
 calculated atomic volumes in the fourth columns of tables A, B, C, D are determined. 
 It must be understood however that these values are based upon somewhat doubtful 
 assumptions respecting the atomic volumes of the elements, and are regarded by Kopp 
 merely as approximations to the truth. 
 
 Since the addition of CH 2 to a compound increases the atomic volume by 22, this 
 number may be taken to represent the atomic volume of CH 2 ; moreover, since C 
 may take the place of H 2 in combination, without altering the atomic volume of the 
 compound, it follows that the atomic volume of C must be equal to that of H 2 ; and 
 
 22 
 therefore the atomic volume of C = -^- = 11, and that of IP also equal to 11, or that 
 
 of II = 5'5. Further, as the substitution of for H 2 produces a slight increase in 
 the atomic volume of a compound, the atomic volume of must be rather greater 
 tli an 11 ; and it is found that, by assuming the atomic volume of 0, when it takes 
 place of H 2 (that is to say, in a radicle, as when acetyl, C 2 H 3 0, is formed from ethyl, 
 C' 2 H 5 ), to be equal to 12'2, results are obtained agreeing very nearly with those of 
 
 observation. But when oxygen occupies the position which it has in water, -rrO, its 
 
 atomic volume is smaller. The specific gravity of water at the boiling point is 
 
 18 
 0-9579 ; hence its atomic volume at that temperature is = 18'8 ; now the 
 
 2 atoms of hydrogen occupy a space equal to 11 ; hence the volume of the oxygen 
 is 7*8. The same value of the atomic volume substituted for in the formula of the 
 several compounds belonging to the water-type, in which it occupies a similar place, 
 that is to say, outside the radicle, gives results agreeing nearly with observation. 
 That a given quantity of a substance should occupy different spaces, under different 
 circumstances, is a fact easily explained, when it is remembered that the particles of 
 a body cannot be supposed to be in absolute contact, but are separated by certain 
 spaces, which, increase or diminish according to the temperature of the body, and 
 according as it is in the solid, liquid, or gaseous state. 
 
 From these values of the atomic volumes of the elements, carbon, hydrogen, and 
 oxygen; viz. 
 
 Atomic volume of C ....... . = 11 
 
 H ........ = 5-5 
 
 O (within the radicle) . . . . = 12'2 
 
 O (without the radicle) . . . . = 7*8 
 
 the calculated values of the atomic volumes of liquids, in the fourth column of Table 
 A are deduced. The method of calculation may be understood from the following 
 examples : 
 
 Benzene, C 6 H 6 = C 6 H 5 .H. 
 Atomic volume of C 6 ...... = 66 
 
 H 8 ...... = jtf 
 
 benzene ...... = 99 
 
 Aldehyde, C 2 H 4 = C 2 H 9 O.H. 
 Atomic volume of C 2 ....... = 22 
 
 H 4 ....... = 22 
 
 (within the radicle) . . . = 12-2 
 
 aldehyde ...... = 56-2 
 
 Alcohol, C 2 H 6 = C2 
 
 Atomic volume of C 2 ....... = 22 
 
 H 6 ....... = 33 
 
 (without the radicle) . . . = 7'8 
 
 alcohol . . = 62-8 
 
446 
 
 ATOMIC VOLUME. 
 
 Acetic acid, C 2 H 4 2 = 
 
 H 
 
 C 2 H 3 
 Atomic volume of C 2 . 
 
 H . . . . 
 
 (within the radicle) 
 
 ,, (without the radicle) 
 
 acetic acid 
 
 22 
 22 
 12-2 
 
 _L. 
 64-0 
 
 Acetic anhydride C 4 H C 3 = 
 
 Atomic volume of C 4 . 
 
 H . . . . 
 
 O 2 (within the radicle) 
 
 O (without the radicle) 
 
 acetic anhydride . 
 
 Oxalate of methyl, C 4 H 6 4 = 
 
 Atomic volume of C* . 
 
 H 6 . . . . 
 O 2 (within the radicle) 
 
 O 2 (without the (radicle) 
 
 oxalate of methyl . 
 
 0. 
 
 = 44 
 
 = 33 
 
 = 24-4 
 
 = 7-8 
 
 = 109-2 
 
 = 44 
 
 = 33 
 
 = 24-4 
 
 = 15-0 
 
 117-0 
 
 Liquids containing Sulphur. Sulphur enters into combination in various ways ; 
 sometimes taking the place of oxygen in the type HH.O (as in mercaptan) ; sometimes 
 taking the place of carbon within a radicle (as in sulphurous anhydride) SO.O, com- 
 pared with carbonic anhydride CO.O ; sometimes replacing oxygen within a radicle (as 
 in sulphide of carbon), CS.S, compared with carbonic anhydride. In the first and 
 second cases, the atomic volume of sulphur-compounds may be calculated by attri- 
 buting to sulphur, (8 = 32), the atomic volume 22*6, those of the other elements re- 
 maining as above ; in the third case, the atomic volume of sulphur appears to be 
 greater; viz. 28 '6. 
 
 'Ex.. Mercaptan, C 2 H 6 S = 
 
 Atomic volume of C 2 
 ii - ** 
 
 .. 
 mercaptan 
 
 = 22 
 
 = 33 
 
 = 22-6 
 
 = 77-6 
 
 Sulphide of carbon, CS 2 = CS.S. 
 
 Atomic volume of C . . = 11 
 S (within the 
 
 radicle) . = 28'6 
 S (without the 
 
 radicle) . = 22-6 
 sulphide of carbon . = 752-2 
 
 TABLE B. Atomic Volumes of Liquid Sulphur-corn^ 
 
 
 
 
 Atomio Volume at the Boiling Point. 
 
 Substance. 
 
 Formula. 
 
 Atomic 
 Weight. 
 
 
 
 
 
 
 
 Calculated. 
 
 Observed. 
 
 Mercaptan . 
 
 C' 2 H G S 
 
 62 
 
 77-6 
 
 76-0... 76-1 at 36 C. 
 
 Amylic mercaptan . 
 
 C 5 H 12 S 
 
 104 
 
 143-6 
 
 140-1. ..140-5 120 
 
 Sulphide of methyl 
 
 C 2 H fi S 
 
 62 
 
 77-6 
 
 757 . . 41 
 
 Sulphide of ethyl . 
 
 C 4 H 10 S 
 
 90 
 
 121-6 
 
 120-5.. .121-5 91 
 
 Bisulphide of methyl 
 Sulphurous anhydride 
 Sulphite of ethyl . 
 Sulphide of carbon 
 
 C-'H 6 S 2 
 SO 2 
 C 4 H ,o S0 3 
 
 cs a 
 
 94 
 64 
 138 
 76 
 
 100-2 
 42-6 
 149-4 
 62-2 
 
 100-6. ..1007 114 
 43-9 . . -8 
 148-8... 149-5 160 
 62-2... 62-4 47 
 
 Chlorides, Bromides, and Iodides. In liquid compounds of this class, the atomic 
 volume of Cl is supposed to be 22-8, that of Br = 27'8, and that of I = 37'5, those of 
 the other elements remaining as above. 
 
 
ATOMIC VOLUME. 
 
 447 
 
 TABLE C. Atomic Volumes of Liquid Chlorides, Bromides, and Iodides. 
 
 Substance. 
 
 Formula. 
 
 Atomic 
 Weight. 
 
 Atomic Volume at the Boiling Point. 
 
 Calculated. 
 
 Observed. 
 
 Dichlorinated ethylene 
 
 C 2 H 2 C1 2 
 
 97 
 
 78-6 
 
 79V . at 37 C. 
 
 Chloride of carbon 
 
 C 2 C1 4 
 
 166 
 
 113-2 
 
 115-4 . . 123 
 
 Chloride of ethylene . 
 
 C 2 H 4 C1 2 
 
 99 
 
 89-6 
 
 85-8.-. 86-4 85 
 
 monochlorinated . 
 
 C 2 H 3 CP 
 
 133-5 
 
 106-9 
 
 105-4. 107-2 115 
 
 dichlorinated 
 
 C 2 H 2 C1 4 
 
 168 
 
 124-2 
 
 120-7. ..121-4 137 
 
 ,, trichlorinated 
 
 C 2 HCP 
 
 202-5 
 
 141-5 
 
 143 . . 154 
 
 Chloride of tetrylene 
 
 C 4 H 8 CP 
 
 127 
 
 133-6 
 
 129-5... 133-7 123 
 
 Monochlorinated chloride 
 
 
 
 
 
 of methyl 
 
 CH 2 CP 
 
 85 
 
 67-6 
 
 64-5 . . 30-5 
 
 Chloroform 
 
 CHCP 
 
 119-5 
 
 84-9 
 
 84-8... 65-7 62 
 
 Chloride of carbon 
 
 CC1 4 
 
 154 
 
 102-2 
 
 104-3.. .107-0 78 
 
 Chloride of ethyl 
 
 C 2 H 5 C1 
 
 64-5 
 
 72-3 
 
 71-2... 74-5 11 
 
 monochlorinated . 
 
 C 2 H 4 CP 
 
 99 
 
 89-6 
 
 86-9... 89-9 64 
 
 dichlorinated 
 
 C 2 H 3 CP 
 
 133-5 
 
 106-9 
 
 105-6.. .109-7 75 
 
 Chloride of amyl 
 
 C 5 H U C1 
 
 106-5 
 
 138-3 
 
 135-4...137-0 102 
 
 Chloral .... 
 
 C 2 HCPO 
 
 147-5 
 
 108-1 
 
 108-4. ..108-9 96 
 
 Chloride of acetyl 
 
 C 2 H :J OC1 
 
 78-5 
 
 73-5 
 
 74-4... 75-2 55 
 
 Chloride of benzoyl . 
 
 C 7 H 5 OC1 
 
 140-5 
 
 139-5 
 
 134-2.. .137-8 198 
 
 Bromine .... 
 
 Br 2 
 
 160 
 
 55-6 
 
 54 ... 287 63 
 
 Bromide of methyl . 
 
 CH 3 Br 
 
 95 
 
 55-3 
 
 58-2 . . 13 
 
 Bromide of ethyl 
 
 C 2 H 5 Br 
 
 109 
 
 77-3 
 
 78-4 . . 41 
 
 Bromide of amyl 
 
 C 5 H"Br 
 
 151 
 
 143-3 
 
 149-2 . . 119 
 
 Bromide of ethylene . 
 
 C-H'Br 2 
 
 188 
 
 99-6 
 
 97-5... 99/9 130 
 
 Iodide of methyl 
 
 CH 3 I 
 
 142-1 
 
 65-0 
 
 65-4... 68-3 43 
 
 Iodide of ethyl 
 
 C 2 H 6 I 
 
 156-1 
 
 87-0 
 
 85-9... 86-4 71 
 
 Iodide of amyl 
 
 C 5 H"I 
 
 198-1 
 
 153-0 
 
 152-5.. .155-8 147 
 
 Chloride of sulphur . 
 
 SCI 
 
 67-5 
 
 . 
 
 45-7 . . 140 
 
 Chloride of phosphorus 
 
 PCP 
 
 137-5 
 
 
 93-9 . . 78 
 
 Bromide of phosphorus 
 
 PBr 3 
 
 271 
 
 . 
 
 108-6 . . 175 
 
 Chloride of silicon 
 
 SiCl 4 
 
 170 
 
 
 121-6 . . 59 
 
 Bromide of silicon 
 
 SiBr 4 
 
 348 
 
 . 
 
 144-0 . . 153 
 
 Chloride of arsenic 
 
 AsCP 
 
 181-5 
 
 f 
 
 94-8 . . 133 
 
 Chloride of antimony 
 
 SbCP 
 
 235-5 
 
 
 100-7 . . 223 
 
 Bromide of antimony 
 
 SbBr 3 
 
 369 
 
 
 116-8 . . 275 
 
 Chloride of tin 
 
 SnCl 4 
 
 .260 
 
 . 
 
 132-4 . . 115 
 
 Chloride of titanium . 
 
 TiCl 4 
 
 92 
 
 
 
 126-0 - . . 136 
 
 The compounds PC1 S and AsCP, have nearly equal atomic volumes: whence it may 
 be inferred that phosphorus, and arsenic, in their liquid compounds, have equal atomic 
 volumes. The same conclusion may be drawn regarding tin and titanium since the 
 atomic volumes of SnCl 4 and TiCl 4 are nearly equal. 
 
 Nitrogen-compounds. In compounds belonging to the ammonia type, the atomic 
 volume -of nitrogen is 2 '3. This result is deduced from the observed atomic volume of 
 phenylamine C 6 H 7 N, which is 106-8. Now the atomic volume of 6C + 7H = 6 . 11 + 
 7.5-5= 104-5, which number, deducted from 106-8, leaves 2-3 for the atomic volume 
 of nitrogen. 
 
 The atomic volume of cyanogen deduced from the observed atomic volume of cyanide 
 of phenyl, CN.C 6 H 5 , or C 7 H 5 N, is nearly 28. Thus : 
 
 Atomic volume of C 7 H S N = 121-6 
 
 C 6 H 5 = 93-5 
 
 CN = 28-1 
 
 A similar calculation, founded on the observed atomic volume of cyanide of methyl, 
 C 2 H S N, gives, for the atomic volume of cyanogen, the number 26-8. The atomic volume 
 of liquid cyanogen determined directly at 37 or 39 C. aboTe its boiling point, is 
 
448 
 
 ATOMIC VOLUME}. 
 
 between 28-9 and 30'0. As a mean of these values, the atomic volume of cyanogen 
 may be assumed to be 28 ; and with this value the atomic volumes of the liquid cya- 
 nides are calculated. Thus, for 
 
 PfT 
 
 Oil of mustard (sulphocyanate of allyl), C 4 H 5 NS = Qq 
 
 Atomic volume of C 3 H 5 . --= 60-5 
 
 CN . = 28-0 
 
 S (without the radicle) = 22*6 
 
 oil of mustard . . = 111-1 
 
 The atomic volumes of compounds containing the radicle NO 2 , are calculated on the 
 hypothesis that the atomic volume of that radicle is 33, which agrees nearly with the 
 observed atomic volume of liquid peroxide of nitrogen. Thus : the atomic volume of 
 nitrite of amyl, C 5 H n N0 8 = at. vol. of C 5 H U + at. vol. of N0 2 = 115'5 + 33 = 148'5. 
 
 TABLE D. Atomic Volumes of Liquids containing Nitrogen. 
 
 Substance. 
 
 Formula. 
 
 Atomic 
 Weight. 
 
 Atomic Volume at the Boiling Point. 
 
 Calculated. 
 
 Observed. 
 
 Ammonia 
 
 H 3 N 
 
 17 
 
 18-8 
 
 22-4... 23-3 at 10... 16 C.* 
 
 Ethylamine 
 
 C 2 H 7 N 
 
 45 
 
 62-8 
 
 65-3 . . at 18-7 
 
 Tetrylamine 
 
 C 4 H U N 
 
 73 
 
 106-8 
 
 
 Amylamine . . 
 
 C 5 H 13 N 
 
 87 
 
 128-8 
 
 125-0 . . 94 
 
 Octylamine . . 
 
 C 8 H 19 N 
 
 129 
 
 194-8 
 
 190-0 . . 170 
 
 Phenylamine 
 
 CH 7 N 
 
 93 
 
 106-8 
 
 106-4.. .106-8 . 184 
 
 Toluidine . . - 
 
 C 7 H 9 N 
 
 107 
 
 128-8 
 
 
 Ethylphenylamine 
 
 C 8 HN 
 
 121 
 
 150-8 
 
 150-6 . . 204 
 
 Diethylphenylamine 
 
 CiH la N 
 
 149 
 
 194-8 
 
 190-5 . . 213-5 
 
 Cyanogen 
 
 CN 
 
 26 
 
 28-0 
 
 28-9... 30-0 . 16 f 
 
 Hydrocyanic acid 
 
 CHN 
 
 27 
 
 33-5 
 
 39-1 . . 27 
 
 Cyanide of methyl 
 
 C 2 H 3 N 
 
 41 
 
 55-5 
 
 54-3 . . 74 
 
 Cyanide of ethyl . 
 
 C 3 H 5 N 
 
 55 
 
 77'5 
 
 77-2 . , 88 
 
 Cyanide of tetryl 
 
 C 5 H 9 N 
 
 83 
 
 121-5 
 
 
 Cyanide of phenyl 
 
 C 7 H 5 N 
 
 103 
 
 121-5 
 
 121-6.. .121-9 . 191 
 
 Sulphocyanate of methyl 
 
 C-'H 3 NS 
 
 73 
 
 78-1 
 
 75-2... 78-2 . 133 
 
 Sulphocyanate of ethyl 
 
 C S H S NS 
 
 87 
 
 100-1 
 
 99-1 . . 146 
 
 Oil of mustard 
 
 C 4 H 5 NS 
 
 99 
 
 111-1 
 
 113-1. ..114-2 . 148 
 
 Cyanate of ethyl . 
 
 C 3 H 5 NO 
 
 71 
 
 85-3 
 
 84-3... 84-8 . 60 
 
 Peroxide of nitrogen . 
 
 NO 2 
 
 30 
 
 33-0 
 
 31-7... 32-4 . 401 
 
 Nitrate of methyl 
 
 CH 3 N0 3 
 
 77 
 
 68-3 
 
 69-4 . . 66 
 
 Nitrate of ethyl . 
 
 C 2 H 5 NO s 
 
 101 
 
 90-3 
 
 90-0... 90-1 . 86 
 
 Nitrobenzene 
 
 C G H 5 NO ? 
 
 123 
 
 126-5 
 
 122-6.. .124-9 . 218 
 
 Nitrite of methyl . 
 
 CH NO 2 
 
 161 
 
 60-5 
 
 61-6 . . 14 
 
 Nitrite of ethyl . 
 
 C 2 H 5 N0 2 
 
 75 
 
 82-5 
 
 79-2... 84-6 . 18 
 
 Nitrite of amyl . 
 
 C'lT'NO* 
 
 117 
 
 148-5 
 
 148-4 . . 95 
 
 From the preceding observations and calculations, it appears that the atomic volume 
 of a compound depends, not merely on its empirical, but likewise on its rational formula ; 
 in other words, not merely on the number of atoms of its elements, but further on the 
 manner in which those atoms are arranged. Now a compound may have more than 
 one rational formula, according to the manner in which it decomposes ; and hence it 
 might appear that the calculation of atomic volumes must be attended with consider- 
 alile uncertainty, inasmuch as the atomic volumes of certain elements, as oxygen and 
 sulphur, vary according to the manner in which they enter into the compound. Alcle- 
 
 C 2 H 3 ) C 2 H 3 ) 
 
 hyde, for example, may be represented either as H j 0, or as H I ' and ' as 
 
 the atomic volume of oxygen is 12'2 or 7*8, according as it is within or without, the 
 radicle, the atomic volume of aldehyde will be 56'2 if deduced from the type HII, and 
 
 Botwepn 44 and 50 above the boiling point. 
 About 35 above the boiling point. 
 
 t Between 37 and 39 above the boiling point. 
 27 above the boiling point. 
 
ATOMIC VOLUME. 
 
 449 
 
 61-8 If deduced from the type HH.O. But the atomic weight of aldehyde, and its 
 specific gravity at a given temperature are invariable ; it cannot therefore have two 
 different atomic volumes. It must be remembered, however, that, in speaking of a 
 compound as having several rational formulge, we consider it rather in a dynamical 
 than in a statical point of view ; as under the influence of disturbing forces, and on 
 the point of undergoing chemical change. But if, on the other hand, we regard a 
 compound in its fixed statical condition, as a body possessing definite physical proper- 
 ties, a certain specific gravity, a certain boiling point, rate of expansion, refractive 
 power, &c., we can scarcely avoid attributing to it a fixed molecular arrangement, or, 
 at all events, supposing that the disposition of its atoms is confined within those limits 
 which constitute chemical types. It is found, indeed, that isomeric liquids exhibit 
 equal atomic volumes only when they belong to the same chemical type. If this view 
 be correct, the relation between the atomic volumes of elements and compounds, may 
 often render valuable service in determining the rational formula which belongs to a 
 compound in the state of rest. Thus of the two atomic volumes just calculated for 
 aldehyde, the number 56 '2, deduced from the formula C 2 H 3 O.H, agrees with the 
 observed atomic volume of aldehyde, which is between 56 '0 and 56*9, better than 51*8, 
 
 the number deduced from 
 
 0. This result leads to the conclusion that the 
 
 aldehydes belong to the hydrogen type rather than to the water type. 
 
 There are many groups of liquid compounds, irrespective of isomerism or similarity 
 of type, the members of which have equal or nearly equal atomic volumes. The fol- 
 lowing table exhibits the calculated atomic volumes of several of these groups : 
 
 Water 
 
 H 2 
 
 18-8 
 
 Ether 
 
 C 4 H 10 
 
 106-8 
 
 Ammonia . 
 
 NH 3 
 
 18-8 
 
 c Tetrylic alcohol 
 
 C 4 H>0 
 
 106-8 
 
 
 
 
 Pheuylic alcohol 
 
 C 6 H 6 
 
 106-8 
 
 Bromine . 
 
 Br 2 
 
 55-6 
 
 Tetrylamine 
 
 C 4 HN 
 
 106-8 
 
 Cyanogen . 
 
 (CN) 2 
 
 56-0 
 
 Phenylamine 
 
 C 6 H 7 N 
 
 106-8 
 
 Aldehyde . 
 
 C'H'O 
 
 56-2 
 
 Butyric acid 
 
 C 4 H 8 2 
 
 108-0 
 
 Cyanide of methyl 
 
 C 2 H 3 N 
 
 55-5 
 
 Acetate of ethyl 
 
 C 4 H 8 2 
 
 108-0 
 
 Bromide of methyl 
 
 CH 3 Br 
 
 55-3 
 
 Acetic anhydride 
 
 C 4 H 6 3 
 
 109-2 
 
 
 
 
 Chloral . 
 
 C 2 HC1 3 
 
 108-1 
 
 Alcohol . 
 
 C 2 H 6 
 
 62-8 
 
 Di chlorinated chloride 
 
 
 
 Acetic acid 
 
 C 2 H 4 02 
 
 64-0 
 
 of ethyl 
 
 C-H 3 C1 3 
 
 106-9 
 
 Formate of methyl 
 
 C 2 H 4 2 
 
 64-0 
 
 Monochlorinated chlo- 
 
 
 
 Cyanate of methyl 
 
 C-H 3 NO 
 
 63-3 
 
 ride of ethylene 
 
 C 2 H 3 C1 3 
 
 106-9 
 
 Ethylamine 
 
 C 2 H 7 N 
 
 62-8 
 
 Bromide of phos- 
 
 
 
 Sulphide of carbon 
 
 CS 2 
 
 62-3 
 
 phorus . 
 
 PBr 3 
 
 108-6 
 
 Iodide of methyl 
 
 CH 3 I 
 
 65-0 
 
 
 
 
 
 
 
 Valeraldehyde . 
 
 C 5 H 10 
 
 122-2 
 
 Acetone 
 
 C 3 H 6 
 
 78-2 
 
 Cyanide of tetryl 
 
 C 5 H 9 N 
 
 121-5 
 
 Cyanide of ethyl 
 
 C 3 H 5 N 
 
 77-5 
 
 Bitter almond oil 
 
 C 7 H 6 
 
 122-2 
 
 Sulphocyanate of me- 
 
 
 
 Cyanide of phenyl 
 
 C 7 H 5 N 
 
 121-5 
 
 thyl ... 
 
 C 2 H 3 NS 
 
 78-1 
 
 Sulphide of ethyl 
 
 C 4 H 10 S 
 
 121-6 
 
 Sulphide of methyl . 
 
 C 2 H 6 S 
 
 77-6 
 
 
 
 
 These groups exhibit an approach to the uniformity of atomic volume which is 
 observed in the gaseous state. 
 
 Berthelot has adduced a number of examples, showing that when a liquid compound 
 is formed by the union of two other liquids, whose specific volumes are denoted by A and 
 B, with elimination of x atoms of water, the specific volume of the compound is nearly 
 = A + B scG (the atomic volume of water being denoted by C). Berthelot's obser- 
 vations, however, were made at medium temperatures, not at the boiling points of the 
 liquids (Ann. Ch. Phys. [3] xlviii. 322). 
 
 3. Of Solid Compounds. (H. Kopp, Pogg. Ann. xlvii. 133 ; lii. 243, 262 ; Ann. 
 Ch. Pharm. xxxvi. 1. Ammermuller, Pogg. Ann. xlix. 341. H. Schroder, ibid. 
 i. 552; lii. 269, 282; cvi. 226; cvii. 113. Filhol, Ann. Ch. Phys. xxi. 415. 
 Playfair and Joule, Chem. Soc. Mem. ii. 477; iii. 54, 199; Chem. Soc. Qu. ,T. 
 i. 121. H. Schiff, Ann. Ch. Pharm. cvii. 64; cxii. 88. Grm. i. 6786.) 
 
 The most general relation that has been observed between the atomic volumes of 
 
 of solid compounds is, that isomorphous compounds have equal atomic volumes, in other 
 
 words, their densities are proportional to their atomic weights. Such is the case, for 
 
 example, with carbonate of strontium (strontianite) and carbonate of lead (witherite). 
 
 Formula. At. Weight. Sp. Gr. At. Volume. 
 
 Si^CO 3 147-6 3-60 41-0 
 
 Pb 2 C0 8 267-4 6-47 41-4 
 
 VOL. I. G G 
 
450 
 
 ATOMIC VOLUME. 
 
 If the crystalline forms are only approximately similar, the atomic volumes also arc 
 only approximately equal, the difference being less as the angles of the two crystalline 
 forms are more nearly equal, and their axes more nearly in the same ratio. An 
 alteration of atomic volume, such as is often produced by the introduction of one 
 element into a compound in place of another, is attended with a corresponding altera- 
 tion of crystalline form. The atomic volume may likewise be altered without any 
 change in the composition of the body, viz. by change of temperature, and this also 
 produces in most cases, as Mitscherlich has shown, a corresponding alteration in the 
 magnitude of the angles. In crystals of the regular system, however, variation of 
 temperature produces no alteration either in form or in atomic volume. 
 
 In dimorphous compounds, each modification has a density, and therefore also an 
 atomic volume, peculiar to itself. 
 
 The equality, exact or approximate, of the atomic volumes of isomorphous compounds, 
 has been traced by Hugo Schiff, through several classes of salts, especially in the sulphates 
 of the general form, M 2 S0 4 .7H 2 (vitriols}, in the double sulphates of the magnesian 
 
 K NH 4 ) 
 
 class, '-, >S0 4 .3H 2 0, and in the alums. The atomic volumes of these com- 
 pounds are given in the following table : 
 
 Formula. 
 
 Atomic 
 Weight. 
 
 Specific 
 Gravity. 
 
 Atomic 
 Volume. 
 
 Vitriols. 
 Mg 2 S0 4 . 7H 2 ... 
 
 246 
 
 1-685 
 
 146 
 
 Zn 2 SO 4 . 7H 2 .... 
 
 287 
 
 1-853 
 
 146-9 
 
 Ni'SO 4 . 7H 2 O 
 
 281-2 
 
 1-931 
 
 145-6 
 
 Co 2 S0 4 . 7H 2 
 Fe 2 S0 4 . 7H 2 
 
 281 
 
 278 
 
 1-924 
 
 1-884 
 
 146 
 147-5 
 
 (MgCu)SO 4 . 7H 2 
 
 265-7 
 
 1-813 
 
 146-5 
 
 MgZnSO 4 . 7H 2 
 MgCdSO 4 . 7H 2 
 
 Double Magnesian Sulphates. 
 (NH 4 )MgS0 4 . 3H 2 . 
 
 266-5 
 290-0 
 
 180 
 
 1-817 
 1-983 
 
 1-680 
 
 146-6 
 146-2 
 
 107-1 
 
 KMgSO 4 . 3H 2 O .... 
 
 201-2 
 
 1-995 
 
 100-9 
 
 (NH 4 ,ZnS0 4 . 3H 2 .... 
 
 200-5 
 
 1-910 
 
 104-9 
 
 KZnSO 4 . 3H 2 
 
 221-7 
 
 2-153 
 
 103 
 
 (NH 4 )NiS0 4 . SH^O 
 
 197-6 
 
 1-915 
 
 103-2 
 
 KNiSO*.3H 2 
 
 218-8 
 
 2-123 
 
 103-1 
 
 (NH 4 )CoS0 4 . 3H 2 O 
 
 197-5 
 
 1-873 
 
 105-4 
 
 KCoSO 4 . 3H 2 
 
 218-7 
 
 2-154 
 
 101*6 
 
 (NH 4 )FeS0 4 . 3H 2 .... 
 
 196 
 
 1-813 
 
 108-1 
 
 KFeSO 4 . 3H*O 
 
 217-2 
 
 2-189 
 
 99-2 
 
 (NH 4 )CdS0 4 . 3H 2 .... 
 
 223-7 
 
 2-073 
 
 107-9 
 
 KCdSO 4 . 3H 2 
 
 244-9 
 
 2-438 
 
 100-5 
 
 (NH) 4 CuS0 4 . 3H 2 
 
 199-7 
 
 1-931 
 
 103-4 
 
 KCuSO 4 . 3H0 .... 
 
 220*9 
 
 2-137 
 
 103*3 
 
 Alums. 
 KA1 2 S 2 8 . 12H 2 
 
 474-6 
 
 1-722 
 
 275-6 
 
 NaAl 2 S 2 8 . 12H 2 
 
 458-4 
 
 1-641 
 
 279-2 
 
 (NH 4 )A1 2 S 2 8 . 12H 2 . 
 
 453-4 
 
 1-621 
 
 279-6 
 
 KCrS'O 9 . 12H 2 
 
 600-8 
 
 1-845 
 
 271-4 
 
 (NH 4 )Cr 2 S 2 8 . 12H 2 O .... 
 
 479-6 
 
 1-736 
 
 276-2 
 
 (NH 4 )Fe 2 S 2 8 . 12H 2 
 
 482-0 
 
 1-712 
 
 281-4 
 
 The atomic volumes of the vitriols are very nearly equal; so likewise are those of 
 the alums. Those of the double magnesian sulphates, M(K ; NH 4 )S0 4 3H 2 0, differ 
 somewhat more, the difference between the greatest and least amounting to 8 -9. It 
 is remarkable, however, that the atomic volume of the ammonium- and potassium- 
 salta in each pair differs from the mean value (10 i) by nearly equal values, the former 
 in excess, the latter in defect ; thus, in the first pair we find, 107'1 104 = + 3'1 ; 
 and 100-9 - 104 = - 3-1 ; and in the second pair : 104-9 - 104 = + 0'9; and 
 103 - 101 = - 1-0. 
 
ATOMIC VOLUME. 
 
 451 
 
 The following table contains the atomic volumes of certain chlorides, bromides, 
 and iodides : 
 
 Formula. 
 
 Atomic 
 Weight. 
 
 Specific 
 Gravity. 
 
 Atomic 
 Volume. 
 
 Chlorides. 
 
 36-5 
 139-5 
 63-5 
 55-5 
 65-0 
 135-5 
 143-5 
 98-9 
 79-5 
 58-5 
 104-1 
 
 82-0 
 281-0 
 104-0 
 149-6 
 181-0 
 189-0 
 185-0 
 
 128-0 
 166-2 
 150-0 
 327-0 
 235-0 
 195-6 
 227-0 
 231-0 
 
 1-501 
 5-78 
 2-528 
 2-205 
 2-56 
 5-320 
 5-517 
 3-70 
 2-96 
 2-148 
 3-82 
 
 2-00 
 7-307 
 2-952 
 4-23 
 5-92 
 6-353 
 6-63 
 
 2-25 
 2-85 
 3-45 
 7-644 
 5-35 
 4-917 
 5-91 
 6-07 
 
 24-3 
 
 24-2 
 25-1 
 25-2 
 25-3 
 25-5 
 26-0 
 26-7 
 26-9 
 27-2 
 27-2 
 
 41-0 
 
 384) 
 35-2 V 
 353) 
 30-6-. 
 29-8 [ 
 28-0) 
 
 57-0) 
 58-3 J 
 43-5) 
 42-8^ 
 43-9) 
 39-8) 
 38 -4> 
 38-1) 
 
 
 
 Chloride of calcium 
 
 Chloride of mercuricum 
 
 Chloride of cuprosum 
 
 Chloride of sodium 
 
 Bromides. 
 
 Bromide of mercurosum 
 
 Bromide of barium ...... 
 
 
 
 Iodides. 
 
 Iodide of potassium 
 
 Iodide of mercurosum 
 
 Iodide of barium 
 
 
 
 It will be observed that the atomic volumes of the bromides and iodides do not 
 agree among themselves so nearly as those of the chlorides. The atomic volume of a 
 bromide is not, for the most part, the mean between those of the corresponding chloride 
 and iodide, but approaches more nearly to that of the chloride. (Schiff.) 
 
 That isomorphous compounds do in many instances occupy equal atomic volumes 
 is sufficiently apparent from the preceding examples. Nevertheless, Schroder con- 
 cludes, from calculations founded partly on his own determinations of specific gravity, 
 partly on those of other observers, that equality of atomic volume is not necessarily 
 connected with similarity of crystalline form, but is exhibited by heteromorphous 
 elements and compounds quite as often as by those which are isomorphous, if not 
 oftener. (Pogg. Ann. cvi. 226 ; cvii. 113.) 
 
 The connection between the atomic volumes of compounds and of their elements has 
 not been so fully examined in solids as in liquids ; nevertheless certain general rela- 
 tions have been shown to exist. The most important of these relations, first pointed 
 out by Schroder, and further established by Kopp, is that equivalent quantities of dif- 
 ferent elements^ in uniting with the same quantity of a given element (or compound 
 radicle} receive equal increments of volume. Thus, when 207*4 grammes, or 18-44 
 cub. cent, of lead (Pb 2 ), 112 grm. = 13 c.c. cadmium (Cd 2 ), 637 grm. = 7*2 c.e. copper 
 (Cu 2 ), or 65-2 grm. = 9*2 c.c. zinc (Zn 2 ), unite with 16 grms. of oxygen (0) to form 
 the compounds Pb 2 0, Cd 2 O, &c., the increment of volume is found to be in each case 
 nearly 2-6 cubic centimetres. Again, in the oxidation of 112 grm. iron (Fe 4 ) to ferric 
 oxide, Fe^O 3 , the increment of volume is 8-1 = 3 x 27 c.c. The explanation of this 
 law appears to be that certain elements enter into combination with the same atomic 
 volume that they occupy in the separate state. Such, according to Kopp, is the case 
 with the heavy metals : so that, by determining experimentally the atomic volumes of 
 their oxides, chlorides, nitrates, &c., and deducting therefrom the volumes of the 
 metals themselves as given in the table (p. 442), the atomic volumes of 0, 01, NO 3 , &c., 
 
 G o 2 
 
452 ATOMIC VOLUME. 
 
 which cannot be observed directly, may be found ; thus, a comparison of the oxides 
 above-mentioned shows that the atomic volume of oxygen in these compounds is 2'6. 
 
 The metals of the alkalis and earths do not appear to enter into combination with 
 the same volume that they occupy in the free state. Their atomic volumes in com- 
 bination must, therefore, be calculated by deducting from the observed atomic volumes 
 of their salts, the chlorides for example, the volume of the chlorine as determined 
 from the chlorides of the heavy metals, this determination of course resting on the 
 assumption that the atomic volume of the chlorine in combination is the same in all 
 analogous compounds. 
 
 On these principles, Kopp has made the following estimations of the atomic volumes 
 of the alkali-metals, earth-metals, and certain salt-radicles : 
 
 NH 4 in its salts . . .... . . 17'4 
 
 K , 187 
 
 Na . ...... . . 10*4 
 
 Ba . . . . ... . . 11-4 
 
 Sr . . . . ... . . .8-6 
 
 Ca 4-8 
 
 CO 3 in the carbonates of Pb, Cd, Fe, Mn, >Ag, Zn, Ba, Ca, K, Mg, 
 
 Na, Sr 12-1 
 
 NO 3 in the nitrates of Pb, Ag, NH 4 , Ba, K, Na, Sr . 28*6 
 
 SO 4 in the sulphates of Cu, Ag, Zn, Ca, Mg, Na . . .18*9 
 
 SO 4 in the sulphates of Pb, Ba, K, Sr . . . .14-9 
 
 Cl in the chlorides of Pb, Ag, Ba, Na 15*7 
 
 Cl in the chlorides of NH 4 , Ca,.K, Ccu, Hg, Hhg, Sr . . 19-6 
 
 in the oxides Pb 2 0, Cd 2 0, Cu 2 0, Hg 2 0, Zn 2 0, SnO, Sb 2 3 , 
 
 Fe 4 3 ,Co 4 3 , Bi 2 3 , Pb 3 2 ... . . . .2-6 
 
 in the oxides Ccu 2 0, Ag 2 0, Hhg 2 0, Mo 2 3 , . . , . . 5-2 
 
 These values were determined in 1841, and many of them require correction accord- 
 ing to the atomic weights and densities since established. According to Schroder 
 (loc. cit.), the relations upon which they depend are true only with regard to isomor- 
 phous compounds, being regulated by the following general law: " If two elements OP 
 groups of elements, A, B, &c., unite with other elements or groups, C, D, E, &c., form- 
 ing compounds AC and EC, AD and BD, AE and BE, &c., which belong to the same 
 type, and are isomorphous by pairs, the differences of atomic volume of AC and B C, AD 
 and BD, AE andBE, &c., are always s equaL; but, if these pairs of compound are not 
 isomorphous, or belong to different types, then the differences of atomic volume are 
 unequal." ,.....-, 
 
 Messrs. PI ay fair and Joule have observed some remarkable relations between 
 the atomic volumes of crystallised salts and that of the water which they contain, viz. 
 1. In certain highly hydrated salts, viz. the arsenates and phosphates with 12 at. water 
 and in carbonate of sodium with 10 at. water, the volume of the entire molecule is the 
 same as that of the water of crystallisation frozen into ice, the particles of the acid 
 and base appearing to be interposed between those of the water without increasing 
 the total bulk. The following table contains the specific gravity of some of these 
 salts, as calculated upon this hypothesis, and as determined by direct experiment : 
 
 Salt. Specific Gravity. 
 
 Exp. Calc. 
 
 Na 2 C0 3 . 10H 2 1-454 1-463 
 
 Na 2 HP0 4 . 12H 2 ..... 1-525 1-527 
 
 Na 3 P0 4 . 12^0 1-622 1-622 
 
 Na 2 HAs0 4 . 12H 2 .... 1-736 1736 
 
 Na 3 As0 4 . 12H 2 1-804 1-534 
 
 In cane-sugar and milk-sugar, the atomic volume is the same as that of the hydrogen 
 and oxygen, supposed to be united as water and frozen. Specific gravity of cane- 
 sugar on this hypothesis = 1-586; by experiment =1'586; of milk-sugar, by calculation 
 1-534; by experiment 1-531. 
 
 2. In another class of salts, including the hydrated magncsian sulphates (M 2 O.S0 8 
 + 6IPO), normal sulphate of aluminium, borax, pyrophospliate of sodium, and the 
 alums, the atomic volume is made up of the solid water and of the base (M 2 or 
 M 4 3 ) ; in other words, the volume of the hydrated salt is made up of that of the water 
 of crytallisation frozen into ice, and that of the base as it exists in the free state, or 
 in the anhydrous salt. (For details see the memoirs cited on page 449.) 
 
 ATOMIC WEIGHTS. The ultimate constitution of matter, and its finite or 
 infinite divisibility, have been made the subjects of speculation and argument from 
 almost the earliest times. The molecular idea of matter seems to have prevailed in 
 the primitive philosophies of the Hindoos, Phoenicians, and Egyptians, from the last 
 
ATOMIC WEIGHTS. 453 
 
 f whom it was probably transmitted to the Greeks. Among them, we find the notion 
 of finite divisibility constituting the basis of the cosmogony of Democritus, who appa- 
 rently acquired the doctrine directly from Leucippus. Subsequently Epicurus, and the 
 Epicureans generally, extended the atomic hypothesis, which, however, was strongly 
 opposed by Empedocles and the later Pythagoreans, who contended for the in- 
 finite divisibility of matter, and for its continuity in any given mass. Plato and 
 Aristotle also, especially the latter, advocated the notion of infinite divisibility. In 
 modern times, the doctrine of material atoms was maintained by Newton, and opposed 
 by Descartes, Leibnitz, and Euler. After the time of Euler, the question of the ultimate 
 constitution of matter fell into some neglect, although the non-atomic view seems to 
 have been generally preferred, until Dalton, in 1804 8, revived the atomic hypothesis, 
 in order to account for the phenomena of chemical combination in definite and multiple 
 proportions, which he first brought prominently into notice. Prior to his discovery, the 
 chemical composition of bodies, as determined by analysis, had been expressed in 
 centesimal proportions only, whereby the relations in composition of different bodies 
 wre in great measure concealed from observation. Thus, the relative composition of 
 olefiant gas and marsh gas, was expressed very imperfectly by saying that the former 
 contained 85'7 per cent, of carbon and 14'3 per cent, of hydrogen, while the latter 
 contained 75'0 per cent, of carbon and 25'0 per cent, of hydrogen. It was from the 
 results of an examination of these two gases that Dalton was first led to the conception 
 of his theory. He ascertained that both gases consist of carbon and hydrogen only, 
 and set out the centesimal composition of each in the customary manner. But he 
 observed further, that the ratio of hydrogen to carbon is exactly twice as great in the 
 one case as in the other ; that in olefiant-gas, for instance, the carbon is to the hydro- 
 gen as 6 to 1, whereas in marsh-gas it is as 6 to 2. Or, in other words, a given 
 quantity of carbon unites with either one or two proportions of hydrogen to form the 
 respective compounds, olefiant-gas and marsh-gas. Dalton, whose turn of mind was 
 essentially mechanical, explained the constitution of these two compounds by supposing 
 that the first consisted of 1 at. of carbon united with 1 at. of hydrogen ^0, while 
 the second consisted of 1 at. of carbon united with 2 at. of hydrogen 00, the atom 
 of carbon being considered to have 6 times the weight of the atom of hydrogen. 
 He then calculated the composition of other bodies on the same plan, and found, for 
 instance, that the quantity of hydrogen which unites with 6 pts. of carbon to form 
 olefiant gas, unites with 8 pts. of oxygen to form water. Hence water was represented 
 by the symbol Q, the atom of oxygen being considered to have 8 times the weight 
 of the atom of hydrogen. The crowning point of Dalton's theory was reached when 
 he discovered that the numbers which expressed the respective combining proportions 
 of carbon and oxygen with 1 pt. of hydrogen, also expressed the proportions in which 
 they combine with one another. Thus the ratio of carbon to oxygen in carbonic oxide 
 gas was found to be as 6 to 8 ; whereas in carbonic anhydride gas it was as 6 to 
 twice 8. The former compound he considered to result from the union of 1 at. of 
 carbon with 1 at. of oxygen ^0 ; and the latter to result from the union of 1 at. of 
 carbon with 2 at. of oxygen O@O- Dalton extended the same views to the com- 
 pounds of nitrogen, and concluded that the quantity of that element which united with 
 1 pt. of hydrogen to form ammonia (X'0, united with 8 pts. of oxygen to form nitrous 
 gas 0O. We may apply this formula for nitrous gas to the compound known as 
 nitrous anhydride, though, from an error in the rough process of analysis then adopted, 
 it was intended to apply to what is now called nitric oxide, or deutoxide of nitrogen. 
 Even at the present day, it is highly interesting to compare the information afforded 
 by Dalton's expressions for the above-mentioned compounds, with the information 
 afforded by a statement of their respective centesimal proportions, thus : 
 
 Dalton's Expressions. Centesimal Proportion?. 
 
 Olefiant-gas 
 
 Marsh - 
 Water 
 
 gas 
 
 Carbonic oxide 
 Carbonic anhydride 
 Ammonia 
 Nitrous gas . 
 
 85-72 + 14-28 
 75-00 + 25-00 
 88-89 + 11-11 
 42-86 + 57-14 
 27-27 + 72-73 
 82-35 + 17-65 
 36-80 + 63-20 
 
 Dalton thus established that general principle in chemistry known as the law of 
 combination in definite and multiple proportions. He showed that a par- 
 ticular number might be selected for every element, in such a manner that the propor- 
 tions by weight in which any two or more elements combine with one another, should 
 be always in the ratios of their respective numbers, or of different multiples of those 
 numbers. And he accounted for this law by supposing that the elements unite with one 
 
 G G 3 
 
454 ATOMIC WEIGHTS. 
 
 another atom to atom, and that the proportional number accorded to each particular 
 element expresses the relative weight of its atom. Hydrogen being the lightest 
 substance in nature, was at once chosen by Dalton as the unit in his scale of atomic 
 weights, and the weights of the atoms of other elements were established by ascer- 
 taining, directly or indirectly, the respective quantities of those elements which unite 
 either with 1 pt. of hydrogen, or with the quantity of some other element which unites 
 with 1 pt. of hydrogen. But many chemists, who speedily acknowledged the truth of 
 Dalton's laws of combination, refused to admit the atomic doctrine which he had de- 
 duced therefrom. Among these was Davy, who introduced the word proportion as 
 a substitute for Dalton's word atom, conceiving the use of the latter word to be objection- 
 able, as involving a theoretical assumption. At the present day, the word atom 
 is most generally employed by chemists ; but, while some use it in its strict Dai- 
 toman materialistic sense, others use it, in an abstract sense only, to express the 
 smallest indivisible combining proportion of a body, and consider the proportional 
 number of a body as an ultimate or unexplained property pertaining to it. Dalton's 
 symbols were speedily replaced by those now in use, which represent the abbreviated 
 names of the elements. Every such symbol is used to express one atomic proportion of 
 its particular element. Thus, Cl stands for 3 5 '5 pts. of chlorine, Na for 23 pts. of 
 sodium, and As for 75 pts. of arsenic, as compared with 1 pt. by weight of hydrogen. 
 Every compound body being composed of two or more elementary atoms, is expressed 
 by an allocation of symbols. Thus, common salt or chloride of sodium is represented 
 by the formula NaCl, which implies a compound of 23 pts., or 1 combining proportion 
 of sodium, united with 35 - 5 pts., or 1 combining proportion of chlorine. Again, tri- 
 chloride of arsenic is represented by the formula AsCl 3 , which implies a compound of 
 75 pts., or 1 combining proportion of arsenic, united with 106'5 pts. or 3 combining 
 proportions of chlorine. 
 
 The proportional number or atomic weight of a compound "body is the sum of the 
 atomic weiyhts of its constituents. Thus, the atomic weight of chloride of sodium is 
 58-5 and that of trichloride of arsenic 181-5. The relative quantity of a compound 
 body, represented by its formula, is frequently spoken of as its atom, and there is 
 nothing unphilosophical in such an employment of the word. By the atom of sodium, 
 for instance, is understood, the least indivisible proportion of the elementary body 
 sodium, and by the atom of chloride of sodium, the least indivisible proportion of the 
 compound body chloride of sodium, that can have any existence. Soon after the 
 publication of Dalton's theory, it received a valuable corroboration, through its adap- 
 tability to groupings of elements or compound atoms. Wollaston, in the course of 
 some analytical experiments, noticed, that if in the two carbonates of potassium, 
 the weight, of oxide of potassium be taken as constant, then the weights of car- 
 bonic anhydride in each salt are to one another as 1 to 2 ; and Thomson made a 
 similar observation with regard to the two oxalates of potassium. Hence these salts 
 were represented at that time, in accordance with Dalton's views, as consisting respec- 
 tively of one compound atom of oxide of potassium, united with one or two compoxmd 
 atoms of carbonic anhydride, and with one or two compound atoms of oxalic anhydride. 
 The compound atom of a body, or more correctly the atom of a compound body, is 
 now often spoken of as its molecule, but in many cases there is a distinction between 
 the application of the two words which will be presently adverted to. 
 
 The accuracy of Dalton's laws of combination in definite and multiple proportions, 
 was confirmed by a reference to the previous neglected researches of Wenzel and 
 Bichter upon the double decomposition of salts ; and by the subsequent brilliant 
 researches of G-ay-Lussac upon the laws of combination by volume; in which he 
 showed that the combining proportions of simple and compound gases might be ex- 
 pressed volumetrically or by bulk, as well as numerically or by weight. 
 
 It is worth while to refer for a few moments to the above-mentioned experiments 
 of Wenzel and Richter. If we add together solutions of chloride of sodium and 
 nitrate of silver, which are both neutral salts, we get by double decomposition, 
 chloride of silver and nitrate of sodium, and the mixture still remains neutral. There 
 is no redundancy or deficiency of either sodium or silver, but the quantity of sodium 
 separated from its chloride is exactly sufficient to replace the silver separated from its 
 nitrate, and vice versd. Wenzel of Preyberg in Saxony, as early as the year 1777, 
 made very many analyses of salts with great accuracy, and was thereby enabled to 
 account for this neutrality, resulting from the mutual decomposition of neutral salts, 
 by showing that in all salts the quantities of salt-residue, so to speak, which are com- 
 bined with equal weights of some one metal, will also combine with equal weights of 
 ftnv other metal. Thus, if y grains of chloride of sodium, and z grains of nitrate of 
 BOoimn alike contain x grains of sodium, then (y x} + w grains of chloride of silver, 
 and (z x} + w grains of nitrate of silver will alike contain w grains of silver; 
 IHT.MISP the quantifies x and tt> represent the relative combining proportions of the 
 metals, silver and sodium, which can take the place of one another, and unite with the 
 
ATOMIC WEIGHTS. 456 
 
 same amount of chlorine or other salt radicle, or residue. Eichter of Breslau in 
 Silesia, published, in the year 1792, what may be regarded as an extension of 
 the views and experiments of Wenzel. He showed that the neutrality of a saline 
 solution does not change during the direct precipitation or substitution of its metal 
 by some other, and that the respective quantities of different metals which displace one 
 another in salts, all unite with the same weight of oxygen. He also constructed 
 a table of the quantities of different oxides or bases, which contain replaceable 
 amounts of metal, and of the quantities of different acids which can be neutralised by 
 those quantities of the respective bases. His experimental results were very inaccu- 
 rate, but his notions of chemical decomposition, had they received due attention at 
 the time, must have led directly to the doctrine of combining proportions, if not to 
 the Daltonian theory of atoms. It was not until some time after the publication of 
 Dalton' s views, that Berzelius first called attention to the prior researches of Wenzel 
 and Kichter, as affording a valuable confirmation of the laws of chemical combination 
 which Dalton had enunciated. 
 
 In the establishment of proportional members or atomic weights, two distinct 
 points have to be considered, namely the exact determination of the ratios, according 
 to which bodies combine, and the correct expression or interpretation of those ratios. 
 The first is a question of experiment, while the second is one of judgment or inference. 
 Thus whether the ratio of hydrogen to nitrogen in ammonia is as 1 to 5, or as 1 to 
 4*67 is a question of mere experiment : but whether the atom, or smallest indivisible 
 combining proportion of nitrogen is 4'67 times, or 14 times as heavy as the atom or 
 smallest indivisible combining proportion of hydrogen, and consequently, whether the 
 molecule of ammonia consists of one light atom of nitrogen united with 1 of hydro- 
 gen, or of one heavy atom of nitrogen united with 3 of hydrogen, are questions for 
 the judgment, which can only be decided by an intimate acquaintance with, and careful 
 consideration of very many circumstances relating to the respective bodies and their 
 congeners. The numbers originally chosen by Dalton to express the ratios in which 
 the different elements unite with 1 part of hydrogen, are most of them very in- 
 correct. Thus his number for nitrogen was 5 instead of 4'67, that for carbon 5 instead 
 of 6, that for oxygen 7 instead of 8, that for phosphorus 9 instead of 10'33, that for 
 sulphur 13 instead of 16, and similarly with the remainder. Davy raised the number 
 for oxygen from 7 to 7*5, which Prout, soon after, on theoretical grounds increased to 8. 
 But the first series of numbers, deduced from trustworthy experiments, was drawn up 
 by Berzelius, whose results, the work of a lifetime, must ever excite our highest 
 admiration for the marvellous industry and skill by which they were achieved. Of 
 late years, when analytical and synthetical processes have been so greatly simplified 
 and improved, many of his atomic weights have undergone slight corrections at the 
 hands of Dumas, Marignac, Pelouze, Sta.s, Maumene, Erdmann, Marchand, and others, 
 but the general exactitude of his numbers still remains unimpeached. Berzelius, 
 following the example of Wollaston in this country, selected the atomic weight of 
 oxygen as the unit of his scale, and the same plan was adopted until within this last 
 twenty years by continental chemists in generaL The atomic weight of oxygen 
 was fixed at 100, and those of the other elements estimated in accordance therewith; 
 but the simpler numbers by which most of the ratios are expressed on the hydrogen 
 scale, have eventually secured for it the preference. 
 
 In the year 1815, Prout, in a paper " on the relations between the specific gravities 
 of bodies in the gaseous state, and the weights of their atoms," propounded the idea 
 that the atomic weights of all bodies are multiples of the atomic weight of hydrogen. 
 His opinion was shared by Dalton on other grounds, and met with very general ac- 
 ceptance in this country. But it was never acknowledged by Berzelius, or until lately 
 by any large number of continental chemists Although Prout's views must be con- 
 sidered, in the present state of our knowledge, to rest rather upon a speculative than a 
 substantial philosophical basis, it cannot, be denied that the tendency of modern investi- 
 gation has been to confirm liis law or rather, a certain modification of it, which Dumas 
 first introduced in a definite form, but which Prout himself seems to have admitted. Ac- 
 cording to this modification, the atomic weights of all bodies are multiples by whole 
 numbers of a submultiple of the atomic weight of hydrogen. A striking confirmation of 
 this view occurred in the year 1840, when Dumas and Stas showed that the atomic 
 weight of carbon is exactly 6. In 1843 Dumas also showed that oxygen and hydrogen 
 unite to form water exactly in the ratio of 8 to 1, and his experiments were confirmed by 
 those of Erdmann and Marchand. Then Pelouze and Marignac separately ascertained 
 that the atomic weight of nitrogen is 14; and Maumene, Marignac, and Pelouze, sepa- 
 rately ascertained that the atomic weights of chlorine, silver, and potassium coincide 
 almost absolutely with the numbers of 35'5, 108, and 39 respectively. Pelouze showed 
 also that the atomic weights of sodium, barium, and arsenic are 23, 68 '5, and 75 respec- 
 tively. At the present time, out of fifty-eight elementary atomic weights, calculated 
 
 G 4 
 
456 ATOMIC WEIGHTS. 
 
 from the acknowledged best experiments, not more than half a -dozen differ appreciably 
 from multiples by whole numbers of half the atomic weight of hydrogen. Some of 
 these exceptional numbers ought probably to be doubled, whereby they would accord 
 with Prout's modified law, while others of them can hardly be looked upon as satisfac* 
 torily determined. It is worthy of observation also that the smallest atomic weights 
 which, as a general rule, are those of the best known, and most easily estimated 
 elements, accord the most precisely with Prout's law. Dumas is of opinion that 
 some of the exceptional numbers are multiples of one-fourth the atomic weight of 
 hydrogen. Stas, from an elaborate series of experiments, the exactness of which it 
 seems impossible to exceed, has arrived at the conclusion that Prout's law is not true, 
 or at any rate that it is only approximative^ true. He has obtained the following 
 numbers for potassium, sodium, silver, sulphur, nitrogen, chlorine, and lead. Each 
 number has been derived from numerous closely concordant experiments performed by 
 different processes^ on a scale of magnitude and with a degree of delicacy, hitherto 
 unequalled. His number for potassium, however, is the only one which differs con^- 
 siderably i.e. | per cent, from the usually accepted number: 
 
 Stas's numbers. Differences. 
 
 Potassium ... 39 39-130 + 0'130 
 
 Sodium .... 23 23-050 + 0'050 
 
 Silver . . . .108 107'943 - 0-057 
 
 Sulphur .... 32 32-074 + 0-074 
 
 Nitrogen .... 14 14-041 + 0'041 
 
 Chlorine . . . . 35'5 36-460 - 0-040 
 
 Lead .... 103-5 103-457 - 0'043 
 
 Hence it is apparent that the differences in the experimental determination of the 
 ratios according to which bodies combine with one another, have been reduced within 
 very narrow limits. But the case is far otherwise when we come to consider the in- 
 terpretation of these ratios, or the establishment of the atomic weights of simple and 
 compound bodies. Thus mercury unites with chlorine in two proportions to form 
 calomel and corrosive sublimate respectively. In the former compound the ratio of 
 chlorine to mercury is as 35*5 to 200; and in the latter as 35'5 to 100 ; or as twice 
 35-5 to 200. We have therefore to decide between the numbers 200 and 100, where- 
 with to express the atomic weight of mercury. If we select the number 200, the for- 
 mula of calomel will be HgCl, and that of corrosive sublimate HgCI'. If we select the 
 number 100, the formula of calomel will be Hg-Cl, and that of corrosive sublimate, 
 HgCl. Much the same difficulty also exists in those cases in which two elements combi ne 
 in only one proportion. Thus chlorine unites with silver in the proportion of 35 '5 to 
 108, or to twice 54. Now supposing even that we all agree to represent calomel by 
 Hg'Cl, and corrosive sublimate by HgCl, we have still to consider whether chloride of 
 silver is a body analogous to calomel or to corrosive sublimate, before we can decide 
 upon representing it by the formula Ag 2 Cl, in which Ag = 54, or by the formula AgCl, 
 in which Ag = 108. Again, chlorine unites with aluminium in the single proportion 
 of 35'5 parts of chlorine to 9 parts of aluminium. Chloride of aluminium may conse- 
 quently be represented by the formula A1C1, in which Al = 9 ; or by A1CP, in which 
 : Al = 18 ; or by A1CP, in which Al = 27 ; or by A1-C1, in which Al = 4-5 ; or by 
 APCP, in which Al = 13-5; or by one of many other possible formulae. From n 
 variety of considerations, more or less complicated, the last formula, AFCP, is the one 
 which has been generally but not unaminously adopted. Again, the composition of 
 marsh-gas has been ascertained with the greatest certainty. The ratio of carbon to 
 hydrogen is precisely as 3 to 1. Hence we may represent the gas by the formula CH 
 in which the atomic weight of carbon = 3 ; or by the formula CH 2 , in which C = 6 ; 
 or by the formula CH 3 , in which C = 9 ; or by the formula CH 4 , in which C = 12 ; 
 or we may represent the gas by the formula C 2 H 4 , in which C = 6 ; &c. &c. At the 
 present time, all chemists are agreed that the molecule of marsh-gas contains four atoms 
 of hydrogen, but they disagree as to whether it contains two atoms of carbon having 
 each the value 6, or one atom of carbon only having the value 12. 
 
 It is obvious that the atomic weights of an element and of its combinations, should 
 . be selected so as to express the entire series of combinations by the simplest series of 
 formulae ; so as best to accord with the chemical properties and metamorphoses of the 
 bodies ; so as best to illustrate their analogies with other bodies ; and so as to be in 
 relation with their physical properties, such as their specific volumes, specific heats, 
 isomorphism, &c. Now it so happens that these different requirements, chemical and 
 physical, are not always satisfied by one and the same number. Hence we have to 
 subordinate requirements, much in the same manner that zoologists and botanists sub- 
 ordinate characters, and to select that atomic weight which fulfils the greatest number, 
 or rather the most important of them. Many of the discrepancies which were formerly 
 thought to exist between the numbers deduced respectively from chemical and physical 
 
ATOMIC WEIGHTS. 457 
 
 considerations, have of late years been satisfactorily explained away ; and we have 
 every reason to believe that with increasing knowledge leading to higher generalisations, 
 all such anomalies as at present exist will also disappear. 
 
 In a determination of the least indivisible combining proportion, or chemical atom 
 of a body, it is clear that purely chemical considerations must be entitled to the greatest 
 weight, and to some of these we will now direct our attention. If we examine marsh- 
 gas, for instance, we soon perceive that its molecule contains four atoms of hydrogen ; 
 because we find ourselves able to displace one-fourth, or two-fourths, or three-fourths, 
 or four-fourths of. its hydrogen. In other words, we find that its hydrogen is divisible 
 into four equal parts; and as the atom of hydrogen expresses the least indivisible part 
 of hydrogen that can enter into a combination, it is evident that marsh gas must con- 
 tain four of such parts, or four atoms, of hydrogen. Thus taking the formula C*H 4 for 
 marsh-gas, we have the following series of derivatives, the constitution of which could 
 not be expressed, save by according four atoms of hydrogen to the molecule of the gas. 
 
 C*H 4 Marsh-gas O H 4 . 
 
 C* H 3 C1 Chloride of methyl C* H 3 Na Sodium-methyl. 
 
 O H 2 C1 2 Bichloride of methylene . . 
 
 OHCP Chloroform C*HI 3 lodoform. 
 
 C* Cl 4 Tetrachloride of carbon . . 
 
 Hence the metamorphoses of marsh-gas show that the most simple formula by which 
 the ratio of its carbon and hydrogen can be expressed, namely, CH, is not the proper 
 formula of the body. Again, the quantity of marsh-gas, which is the resultant of any 
 reaction, cannot be expressed with less than four atoms of hydrogen. Thus, when 
 acetic acid is decomposed by heat, we have the reaction, C 2 * X H 4 0'* = C*H 4 + C^O 2 . 
 The quantity of carbon C*, which unites with 4 pts. of hydrogen to form marsh-gas, 
 unites with 32 pts. of oxygen to form carbonic anhydride ; but whereas the quantity 
 of hydrogen in marsh-gas is experimentally divisible into 4 pts., the quantity of oxy- 
 gen in carbonic anhydride is experimentally divisible into 2 pts. only ; so that while 
 we represent marsh-gas by the formula C J H 4 , we represent carbonic anhydride by 
 the formula C* O 2 , as will be again referred to. 
 
 The same class of chemical reasons which induce us to regard marsh-gas as tetra- 
 hydric, also induce us to regard ammonia as trihydric. In ammonia we can replace 
 one-third, or two-thirds, or three-thirds of its hydrogen, but we cannot replace one- 
 fourth, or two-fourths, or three-fourths. The hydrogen in marsh-gas being divisible 
 into 4 equal parts, the hydrogen in ammonia is divisible into 3 equal parts only, and 
 consequently the molecule of ammonia contains 3 indivisible proportions or atoms of 
 hydrogen. We are acquainted with many ammonias in which one, two, and three- 
 thirds of the hydrogen are displaced, for example : 
 
 N* H 3 Ammonia. N J HI 2 Diniodamide 
 
 N* H' 2 K Potassamine N* Hg 3 Trimercuramine, &c. &c. 
 
 But the most striking illustration of displacement by thirds is afforded by Hofmann's 
 researches on the volatile alkaloids, in which he successively displaced one, two, and 
 three atoms of hydrogen in ammonia by a mere coi.tinuation of one and the same 
 process : 
 
 Ammonia. Ethylia. Diethylia. Triethylia. Ethyl-methyl-aniliiie. 
 
 (H (H (H (Et ( Et 
 
 N- 3H N- Ifl N* }Et N- }Et N- hie &c. &c. 
 
 (H (Et (Et (Et (Ph 
 
 Again, in ninety-nine cases out of a hundred, the quantity of ammonia which is the 
 agent or resultant of a reaction, must contain 3 or some multiple of 3 atoms of 
 hydrogen. Thus when ammonia results from the hydrogenation of nitric acid, we 
 obtain, for every molecule of nitric acid containing 1 atom of hydrogen, a quantity of 
 ammonia containing 3 atoms; and when ammonia reacts with benzoic chloralde- 
 hyde to form benzamide and sal-ammoniac, we require, for every molecule of benzoic 
 chloraldehyde decomposed, a quantity of ammonia containing twice 3 atoms of hydrogen, 
 2N* II 3 ; and so in other instances. In the great majority also of compounds which 
 ammonia forms directly with other bodies, the quantity of combining ammonia must 
 necessarily be represented with 3 or some multiple of 3 atoms of hydrogen. Thus the 
 single molecule of aldehyde unites with N* H 3 , and the single molecule of nitrate of 
 silver with 2N* H 3 . &c. Express these combinations or reactions how we please, we 
 cannot represent them save with a proportion of ammonia containing 3 or some mul- 
 tiple of 3 atoms of hydrogen, and ninety-nine cases out of a hundred will yield the same 
 result. In those few exceptional cases in which the combining or reacting ammonia need 
 not necessarily be represented with 3 atomsof hydrogen, it may be, and we contend ought 
 to be, so represented. Thus when ammonia is decomposed by excess of chlorine, the re- 
 
 * 
 
 action might be expressed, thus: N 3 + Cl - N ; 'C1 + IIC1: but it is quite certain 
 
458 ATOMIC WEIGHTS. 
 
 that the molecule of chloride of nitrogen contains 3 at. of chlorine, and consequently 
 the reaction by which it is produced ought to be expressed thus : N* H 3 + Cl 8 =* 
 N* Cl 3 + 3HC1 ; and so in other instances. 
 
 The same class of chemical reasons which induce us to regard marsh-gas as tetra- 
 hydric and ammonia as trihydric, also induce us to regard water as dihydric. In water 
 we can replace one-half or two-halves of the hydrogen, but we cannot replace one-third 
 or two-thirds as in ammonia, or one-fourth or three-fourths as in marsh-gas. If we 
 act upon water 0* IF by metallic potassium, we displace one-half its hydrogen to form 
 the very definite body hydrate of potassium 0* KH ; and if we act upon hydrate of 
 potassium by potassium, we displace the other half of the hydrogen and form oxide of 
 potassium 0* KK. Or instead of introducing a second atom of potassium, we may 
 turn out the first one. Thus if we treat hydrate of potassium 0* KH with iodide of 
 ethyl we obtain alcohol 0* EtH, or we put a molecular grouping called ethyl in the 
 place of the potassium, which displaced one-half the hydrogen of the water. Now if 
 we act upon the alcohol thus formed by potassium, it behaves exactly as did the 
 hydrate of potassium, or in other words it yields the remaining half of the original 
 hydrogen in exchange for potassium, and we obtain ethylate of potassium 0* EtK. If 
 we now act upon this new body by the iodide of methyl or ethyl, we turn out the 
 potassium representing one-half the original hydrogen and obtain ethylate of methyl 
 0* EtMe, or ethylate of ethyl 0* EtEt. 
 
 Again, in ninety-nine cases out of a hundred, the quantity of water, which is the 
 agent or resultant of a reaction must contain 2 or some multiple of 2 atoms of 
 hydrogen. Thus, whenever an alcohol, ketone, or any definite organic substance, 
 yields a hydrocarbon or other compound by dehydration, whenever an organic acid 
 yields a pyroacid, or other pyrogenous product by dehydration, whenever a salt of 
 ammonia, phenylamine, or other volatile alkali loses water, and whenever two com- 
 pounds act upon one another to form a new body with simultaneous elimination of 
 water, whether the action be that of an acid upon a hydrocarbon, of an acid upon an 
 alcohol, of an acid upon an alkali, of an acid upon an acid, of an acid upon a"n aldehyde, 
 of an alkali upon an aldehyde, or of an alkali upon an alcohol, the quantity of 
 water eliminated inevitably contains 2, or some multiple of 2 atoms of hydrogen. 
 Moreover whenever a conjugated compound or diameride, a chloraldehyde, an organo- 
 metallic body, &c. &c., is decomposed by water, the quantity of water which reacts 
 must necessarily be represented with 2 or some multiple of 2 atoms of hydrogen. 
 For example, when water reacts with hippuric acid to form benzoic acid and glycocine, 
 for every molecule of hippuric acid decomposed, we require a quantity of water con- 
 taining 0* H 2 . When glycerin becomes acrolein by dehydration, for every molecule 
 of glycerin decomposed we obtain a quantity of water containing 20* H 2 . When 
 nitric acid reacts with naphthalene to form nitro-naphthalene, for every molecule of 
 nitric acid which reacts, we have eliminated a quantity of water containing 0* H 2 . 
 When acetate of ammonia becomes cyanide of methyl by loss of water, for every 
 molecule of the salt decomposed, we liberate a quantity of water containing 20 r H 2 ; and 
 so in an infinite number of other instances. Again, in the majority of direct compounds 
 which water forms with other bodies, the combining water must be represented with 
 two atoms, or some multiple of two atoms of hydrogen. Thus the molecule of glucose 
 differs from that of fructose, and that of lactine differs from that of dextrine by the 
 addition of 0* H 2 . The molecule of turpentine becomes hydrated turpentine by 
 absorbing 30* H 2 , and so in many other instances. The water of crystallisation in 
 the great majority of hydrated salts must be represented with 2 atoms, or some 
 multiple of 2 atoms of hydrogen. Thus the molecules of chloride of barium, nitrate of 
 mercurosum, and chloride of copper, crystallise with 0* IP ; the molecules of nitrate 
 of cadmium, chloride of manganese, and nitrate of calcium with 20* IF ; the mole- 
 cules of chloride of calcium, nitrate of magnesium, and acetate of sodium with 30* H 2 ; 
 the molecules of microcosmic salt and hydrate of barium with 40* H 2 ; the molecule of 
 borax with 50* H 2 ; the molecules of chloride of aluminium and potassio-sulphate of 
 nickel, with 60* H 2 ; the molecule of common arsenate of sodium with 7 or 12 0* H 2 ; 
 and the molecules of alum and rhombic phosphate of sodium with 120* H 2 , &c. &c. 
 There are some comparatively few salts, the acetate of barium, for example, in which 
 the water of crystallisation might be represented by 0* H 2 , or by l0* H 2 , &c., but 
 none in which it need be so represented, while there are scarcely any reactions in which 
 the resulting or reacting water could possibly be expressed by |0* H 2 or l0* H 2 , and 
 none in which it would be correctly so expressed. 
 
 We have mentioned above that the quantity of carbon which unites with four 
 separable portions of hydrogen to form marsh-gas, also unites with two separable 
 portions of oxygen to form carbonic anhydride. Now each of these separable portions 
 of oxygen is identical with the quantity of oxygen 0*, which unites with 2 parts of 
 hydrogen to form water. 
 
ATOMIC WEIGHTS. 459 
 
 Lastly, when we come to examine hydrochloric acid, we are unable to show that 
 its hydrogen is divisible, and we consequently look upon its molecule as containing but 
 one atom, or one indivisible proportion of hydrogen; whence we represent the com- 
 pound by the formula 01*11; and we may anticipate here by remarking, that all 
 physical evidence tends to show that the molecules of marsh-gas, ammonia, water, and 
 chlorhydric acid contain respectively four, three, two, and one atom of hydrogen. 
 
 In addition to the class of binary hydrides, the atomic weights of the principal 
 members of which we have just considered, there is another large class of hydrogenised 
 bodies, namely, the class of ternary or oxacids, the correct determination of whoso 
 molecules is of the highest importance. The molecule of oxalic acid, for instance, may 
 be represented by the formula OHO 2 * *, or C 2x *H*0 4x * , according as the acid is found 
 to be monhydric or dihydric, monobasic or dibasic. Now the polybasicity of an acid 
 does not depend in any way upon the indivisibility of its formula, but solely upon its 
 possession of certain specific characters ; and the examination of the properties of oxalic 
 acid soon shows us that its molecule must be represented, not by the more simple mono- 
 basic, but by the more complex dibasic formula. In fact the same class of chemical 
 reasons which induce us to regard water as dihydric, must also induce us to regard 
 oxalic acid as dihydric, and so in other instances. Inasmuch as the modes of dis- 
 tinguishing between monobasic, dibasic, tribasic, and tetrabasic acids have been 
 minutely set forth in the article ACIDS, it is unnecessary here to repeat them. "We 
 will only observe that certain special acids, to the properties and metamorphoses of 
 which we shall presently have occasion to advert, are proved by their specific charac- 
 ters to be dihydric and dibasic, namely : 
 
 Carbonic acid H 2 O0 3x * 
 
 Oxalic acid IFC'O 4 ** 
 
 Sulphurous acid H 2 S*0 3 ** 
 
 Sulphuric acid H 2 S*0 4xa! 
 
 We will now turn our attention to the atomic weights of the four elements with 
 which the hydrogen of the four primary hydrides, whose atomic weights we have con- 
 sidered somewhat minutely, is combined ; whereby it will appear that the quantities of 
 carbon, nitrogen, oxygen, and chlorine which we have represented by the symbols 
 O , N x , 0* , and CP , respectively, constitute the atoms of these elements, or the 
 smallest indivisible proportions of them which can enter into chemical combination. 
 To begin with carbon: we wish to prove that 12 parts of that element, or the 
 quantity thereof which combines with 4 parts of hydrogen to form marsh-gas, is 
 the smallest proportion of carbon that can exist in a compound. We find in the 
 first place that the quantity of carbon contained in the great majority of carbon-com- 
 pounds must necessarily be represented by 12, or some multiple of 12 parts. We may 
 adduce in illustration of this position, the primary series of homologous fatty acids and 
 their sodium-salts. 
 
 Formic . C lxl2 H*0 2x 
 
 Acetic . C 2 * I2 H 4 02* 
 
 Propionic . C 3 * 12 H 6 O 2 * 
 
 Butyric . C 4 x 12 H 8 O 2 x 
 
 Valeric . C 5xl2 H'0 2x 
 
 Caproic . C 6xl2 H 12 2x 
 
 C lxl2 H NaO* x2 . Formate 
 
 C 2x > 2 H 3 NaO*x2 f Acetate 
 
 . Propionate 
 
 C 4 * 12 H 7 NaO* x 2 . Eutyrate 
 
 C 5xl2 H 9 NaO*x2 . Valerate 
 
 C 6xl2 H n NaO Sx2 . Caproate 
 
 The ratio of carbon to hydrogen in the sodium-salts, necessitates our expressing 
 the constituent carbon as a multiple of 12. The mere ratio of carbon to hydrogen in 
 the acids, would allow the carbon, in all of them, to be expressed satisfactorily by 
 numbers which are not multiples of 12, but of 6. Valeric acid, for instance, might be 
 represented by the formula C 5 x 6 H 5 0* ; but the circumstance that one-tenth part of its 
 hydrogen can be displaced by sodium prevents the possibility of our halving the 
 hydrogen in its molecule, and consequently of our reducing its carbon from a multiple 
 of 12 to a mere multiple of 6. 
 
 From the circumstance that all carbon-compounds must be represented with 12 
 parts, or some multiple of 12 parts of carbon, it follows that whenever two compounds 
 differ from one another by the different proportions of carbon which they respectively 
 contain, that difference amounts to 12 parts of carbon, or to some multiple of 12 parts. 
 Thus, wood-spirit consists of 16 pts. of oxygen, 4 pts. of hydrogen, and 12 pts. of 
 carbon, whereas in aldehyde we have another 12 parts of carbon, and in acrolein two 
 other 12 parts of carbon in addition, so that the three bodies may be represented by 
 the respective formulae : 
 
 Cixi2H 4 0* Wood-spirit 
 
 C 2xi2 H 4 * Aldehyde 
 
 C 3X12 H'0* . Acrolein 
 
460 
 
 ATOMIC WEIGHTS. 
 
 We are not acquainted with any bodies intermediate in composition between wood- 
 spirit and aldehyde, or between aldehyde and acrolein, nor have we any reason to 
 anticipate their formation at any future time. Again toluene contains 8 parts of hydrogen 
 united with seven times 12 parts of carbon ; whereas cinnamene contains another 12 parts 
 of carbon, and naphthalene three other 12 parts of carbon in addition, thus : 
 
 C 7xl2 H 8 ..... Toluene 
 
 Q8 X i2 jp ..... Cinnamene 
 
 C 9xl2 H 8 ..... Wanting 
 
 C 10X12 H 8 ..... Naphthalene 
 
 Now the probability amounts almost to a certainty that a hydrocarbon intermediate 
 between cinnamene and naphthalene will be discovered, and that a hydrocarbon inter- 
 mediate between toluene and cinnamene, or between cinnamene and the expected com- 
 pound, or between the expected compound and naphthalene will not be discovered. It 
 follows also that when carbon, plus some other element or elements, is added to or 
 taken from a body, the quantity of carbon added or subtracted is always 12 parts, or 
 some multiple of 12 parts. Thus the molecule of sodium-ethyl absorbs 12 parts of 
 carbon, plus some oxygen to form propionate of sodium ; aconitic acid, by the loss of 
 12 parts of carbon, plus some oxygen, becomes citraconic acid ; undphthalic acid, by the 
 loss of twice 12 parts of carbon, plus some oxygen, becomes benzene. Moreover in 
 those series of compounds known as homologous, the quantity of carbon in each 
 successive member of the series increases by 12 parts, as shown in a preceding table of 
 the fatty acids and their sodium-salts. All chemists recognise the fact, which is 
 indeed indisputable, that the smallest increment or decrement of carbon that can be 
 effected in a compound is 12 times ag great as the smallest quantity of hydrogen 
 that can be introduced into or displaced from a compound ; so that if the entire series of 
 carbon-compounds is to be represented by the simplest satisfactory formulae, the atom or 
 smallest combining proportion of carbon must be represented as having 12 times the 
 weight of the atom or smallest combining proportion of hydrogen. But some chemists 
 who from old association still accord to carbon the atomic weight 6, consider that all 
 carbon-compounds contain an even number of atoms of carbon, and that in the decom- 
 positions and recom positions of these compounds, two inseparable carbon-atoms are 
 always concerned. But if we understand the smallest inseparable or indivisible pro- 
 . portion of an element to constitute its atom, the conception of two inseparably asso- 
 ; ciatod atoms is clearly illogical. Two small atoms of carbon, having each the va^ie 
 6, if they can never be separated from each other, must nececessarily constitute one 
 large atom of carbon having the value 12. 
 
 There are two well-known compounds of carbon, namely, carbonic oxide, and car- 
 bonic anhydride, which may possibly be regarded as constituting exceptions to some 
 of our previously made assertions. Thus the molecules of these two bodies may be 
 represented by one or other of the following pairs of formulae : 
 
 C lx6 lx8 Carbonic oxide c ixl2 Ix16 
 
 C lx6 2x8 Carbonic anhydride c ixl2 2 * lfi 
 
 Now provided we recognise the dibasicity of the carbonic, oxalic, and other similar acids, 
 as their chemical properties require us to do, it is quite certain that a proportion of either 
 carbonic oxide or carbonic anhydride, containing only 6 parts of carbon, is incapable 
 of effecting or of resulting from a definite chemical reaction. Carbonic anhydride in 
 particular, is a very frequent product of chemical action, but in no definite decomposi- 
 tion do we ever obtain a smaller proportion of the gas than that represented by 12 
 parts of carbon plus 32 of oxygen. A few illustrations are appended of the formation of 
 carbonic oxide and carbonic anhydride, from the decomposition by heat of three mono- 
 basic acids, namely, the formic, acetic, and benzoic ; of two dibasic acids, namely, the 
 oxalic and tartaric ; and of one tribasic acid, namely, the aconitic, the decomposition 
 of which last has been before referred to. 
 
 Formic acid 
 Acetic acid 
 Oxalic acid 
 Benzoic acid 
 Tartaric acid 
 Aconitic acid 
 
 C Ixl2 H 2 2x 
 C 8xl2 H 4 2x 
 C 2xl2 H 2 O 4x 
 C 7xl2 H0 2x 
 C 4xl2 H 6 6x 
 C 6 x 12 II 4 6 x 
 
 12 O 1 
 12 O 8 
 
 C lxl2 2 
 C lxI2 2 
 C |X12 2 
 
 H 2 
 C 1 x 12 H 4 
 
 C1X12Q2X* + IpO* 
 C GX 12 H 6 
 
 C 3xl2 H 4 3x * + IPO* 
 C 5xl2 H 4 4x ^. 
 
 With regard to nitrogen, all chemists are agreed that 14 parts of that element, 
 or the quantity thereof which combines with 3 parts of nitrogen to form ammonia, is 
 the smallest proportion of nitrogen that can exist in a combination. We find that the 
 quantity of nitrogen contained in the great majority of nitrogenous compounds, in- 
 cluding all salts of ammonia and of organic alkaloids, must necessarily be represented 
 
ATOMIC WEIGHTS. 461 
 
 by 14 parts, or some multiple of 14 parts. Among miscellaneous bodies we may 
 adduce cyanogen, indigo, and nitric acid, each of which contains 14 parts of nitrogen ; 
 urea, asparagin, and chrysammic acid, each of which contains twice 14 parts of nitro- 
 gen ; creatine and carbazotic acid, each of which contains three times 14 parts of 
 nitrogen ; uric acid and caffeine, each of which contains four times 14 parts of nitrogen, 
 &c. &c. From the circumstance that all nitrogenous compounds must be represented 
 with 14 parts of nitrogen, it follows that whenever nitrogen is liberated by a chemical 
 reaction, and whenever nitrogen plus some other element is introduced into a chemical 
 compound, the quantity of nitrogen concerned must be represented by 14 parts or some 
 multiple of 14 parts. Thus by the action of nitric acid upon the hydrocarbons, and 
 upon a great variety of other compounds, we can introduce into the compounds 14 parts, 
 or twice 14 parts, or three times 14 parts, &c. &c. of nitrogen, whereas we cannot 
 introduce any intermediate proportion. Again, when sal-ammoniac is decomposed 
 by chlorine, for every molecule of the salt decomposed, 14 parts of nitrogen are 
 liberated ; and when nitrate of ammonia is decomposed by metallic zinc, for every 
 molecule of the salt decomposed twice 14 parts of nitrogen are liberated; 
 and so on. There are a few bodies formed on the type of one or more atoms of am- 
 monia, in which the ratios of the constituent elements might be satisfactorily expressed 
 by formulae in which the quantity of nitrogen represented was not a multiple of 14. 
 Thus trimercuramine might be represented by the formula N' x47 IIg, and tri- 
 ethylamine, by the formula N lx4 ' 7 C 2 H 5 . Similarly, all derivatives of ammonia in 
 which the whole of the hydrogen is displaced by one and the same metal, hydrocarbon, 
 or halogen, might be represented by formulae in which N = 4'7 ; which formulae 
 moreover, would be more simple than those in which N = 14. But the same class of 
 reasons which induce us to represent the molecule of ammonia with 3 atoms of 
 hydrogen, induce us to represent the molecules of these bodies with 3 atoms of 
 metal, radicle, or halogen. Thus triethylamine is the third of a series of compounds, 
 namely, N 1 * 14 H 2 (C 2 H 5 ), N 1 * "H^H 5 ) 2 , and N 1 *(C 2 H 5 ) 8 , obtained successively by 
 a continuance of the same reaction. Moreover, a quantity of triethylamine containing 1 
 less than 14 parts of nitrogen, is not sufficient to effect any decomposition, or to 
 combine with the molecule of any acid or salt. It is observable that the entire series 
 of compounds is represented most simply by formulae, in which N = 14, although one 
 particular member of the series may be represented most simply by a formula in which 
 N = 47. 
 
 Let us now direct our attention to oxygen. We wish to show that 16 parts 
 of that element, or the quantity thereof which unites with 2 atoms of hydrogen to 
 form water, is the smallest proportion of oxygen that can enter into a combination. 
 We find in the first place that the quantity of oxygen contained in the great majority 
 of definite oxidised compounds, must necessarily be represented by 16 or some mul- 
 tiple of 16 parts. Thus the molecules of all hydrates, double oxides, acids, 
 oxisalts, aldehydes, ketones, alcohols, oxacid-ethers, and a great number 
 and variety of other compounds, doubtless forming together 99 per cent, of all known 
 compounds of oxygen, cannot be represented save with 16 parts, or some multiple of 
 16 parts of oxygen. For example, the molecules of hydrate of potassium, benzoic 
 aldehyde, acetone, chloral, hypochlorite of sodium, &c. &c. each contain 16 parts of 
 oxygen. The molecules of spinelle, brown-hoe matite, camphor, benzile, acetate of sodium, 
 benzoic acid, &c. &c. each contain twice 16 parts of oxygen. The molecules of nitric 
 acid, glycerin, chlorate of potassium, salicylic acid, augitc, &c. &c. each contain three 
 times 16 parts of oxygen. The molecules of phosphate of sodium, perchloric ether, 
 garnet, olivine, sulpJiovinic acid, &c. &c. each contain four times 16 parts of oxygen. 
 The molecules of starch, acid malate of lead, nitrosalicylic acid, &c. &c. each contain 
 five times 16 parts of oxygen. The molecules of m.annite, cream of tartar, &c. &c. each 
 contain six times 16 parts of oxygen, while the molecules of citric acid, pyrophosphate 
 of copper and sodium, &c. &c. contain each seven times 16 parts of oxygen, and so on. 
 From the circumstance that nearly all oxidised compounds must necessarily be repre- 
 sented with 16 or some multiple of sixteen parts of oxygen, it follows that when two 
 bodies differ from one another in composition by the different proportions of oxygen 
 which they respectively contain, that difference amounts to 16 parts or some multiple 
 of 16 parts of oxygen, as is well seen in the two following series of bodies. 
 KC1 Chloride of potassium C 2 H 4 Ethylene 
 
 KC10 1 * 16 Hypochlorite of potassium C 2 H 4 lxlG Aldehyd 
 
 KC10** 1 * Chlorite of potassium C 2 H 4 2 * 16 Acetic acid 
 
 KC10 3x16 Chlorate of potassium C 2 H 4 3 * 16 Glycolic acid 
 
 KC10 4x16 Perchlorate of potassium C 2 H 4 lx16 G-lyoxylic acid. 
 
 It follows also that the quantity of oxygen which can be liberated by any reaction, and 
 which, either alone or together with some other element, can be added to, substracted 
 
462 ATOMIC WEIGHTS. 
 
 from, or displaced in a compound, must be 16 or some multiple of 16 parts. Now 
 why this should be unless the 16 parts constitute an indivisible proportion or chemical 
 atom, is quite inconceivable. We may adduce the following illustrations. Each 
 molecule of nitrate of sodium decomposed by heat into oxygen and nitrite of sodium, 
 yields 16 parts of oxygen. Each molecule of permanganate of potassium, decomposed 
 by sulphuric acid into oxygen and manganese-alum, yields twice 16 parts of oxygen. 
 Each molecule of chlorate of potassium decomposed by heat into oxygen and chloride 
 of potassium, yields three times 16 parts of oxygen. Each molecule of penta chloride 
 of phosphorus, converted by treatment with water into phosphoric chloraldehyde and 
 hydrochloric acid, acquires 16 parts of oxygen in exchange for an equivalent quantity 
 of chlorine. Each atom of alcohol converted into aldehyde by oxidation, reajcts with 
 16 parts of oxygen, and each atom of alcohol converted into acetic acid by oxidation, 
 reacts with twice 16 parts of oxygen. Each molecule of bromacetic acid, converted by 
 the action of water into gly colic acid, acquires 16 parts of oxygen and 1 part of hydro- 
 gen, in exchange for one atom of bromine. Each atom of benzene, converted by treat- 
 ment with nitric acid into nitrobenzene, acquires twice 16 parts of oxygen, and 14 parts 
 of nitrogen, in exchange for one atom of hydrogen, and so on. But precisely as there 
 are some nitrogenised bodies which with the atomic weight of nitrogen = 4 '7, may be 
 divided into thirds, and can thus receive simpler formulae than with the atomic weight 
 of nitrogen = 14 ; so are there some comparatively few oxidised bodies which, with 
 the atomic weight of oxygen = 8, may be divided into halves, and can thus receive 
 simpler formulae than with the atomic weight of oxygen = 16. We have seen, how- 
 ever, that if the comparable molecules of nitrogenised bodies were correctly formulated 
 they would all be represented more simply by formulae in which N = 14, than by 
 formulae in which N = 4'7 ; so it will appear that if the comparable molecules of 
 oxidised bodies were correctly formulated, they would all be represented more simply 
 by formulae in which = 16, than by formulae in which = 8. Those oxidised 
 bodies in which the ratio of the oxygen to the other constituents can be satisfactorily 
 expressed by assigning to the oxygen a number which is not 16 or a multiple of 16, 
 but only 8 or a multiple of 8, comprise most compounds in which the oxygen is united 
 with one kind of matter only, including all the simple metallic oxides. Thus in water 
 and lime, the ratio of the constituent oxygen to the hydrogen and calcium respectively, 
 is as satisfactorily expressed by the formulae O 1 x 8 H, and O 1 x 8 Ca, as by the formulae 
 0i x isjp^ an< i O 1 x 16 Ca 2 . The only question is, which of these pairs of formulae represents 
 the molecules of the two bodies. Now it is no more necessary to argue the point whether 
 O 1 x 8 Ca, is the correct expression for the metallic oxide, lime, than it was to argue the 
 point whether N 1 x 4 ' 7 Hg, was the correct expression for the metallic nitride, mercur- 
 amine. The accordance of a trihydric formula to ammonia, necessitates the accordance 
 of a trimetallic formula to mercuramine, and in a precisely similar manner, the accord- 
 ance of a dihydric formula to water necessitates the accordance of a dimetallic formula 
 to lime. It may be observed, moreover, that many strictly comparable reactions can be 
 effected by means of water, hydrate of calcium, and lime respectively, and that in these 
 cases the quantities of the reagents can only be expressed by the formulae O 1 x 16 HH, 
 QI x iHCa, and O 1 x 16 CaCa. Again, in bodies analogous to ordinary ether and the 
 homogeneous anhydrides, the ratio of the oxygen to the other constituents may be 
 satisfactorily represented by formulae in which the proportion of oxygen is expressed by 
 8 parts only. Thus ether may be represented by the formula O 1 x8 Et, and b enzoic 
 anhydride by the formula O 1 x 8 Bz ; but all arguments founded on mode of formation, 
 on reactions, on vapour-densities, on seriated position and properties, &c. tend to show 
 that the above formulae are not correct expressions of the molecules of the bodies 
 represented, which, like that of water, contain 16 parts of oxygen. Thus, ether is one 
 of the following series of bodies : ' x 16 HEt, ethylate of hydrogen, or alcohol ; O 1 x I6 MeEt, 
 ethylate of methyl; O lxl6 EtEt, ethylate of ethyl or ether; lxI6 PrEt, ethylate of 
 propyl ; and benzoic anhydride is one of the following series : O 1 x l6 HBz, benzoate of 
 hydrogen, or benzoic acid ; O 1 x 16 BzBz, benzoate of benzoyl, or benzoic anhydride ; 
 O 1 x l6 AcBz, benzoate of acetyl, or aceto-benzoic anhydride ; &c. &c. Lastly, in certain 
 dibasic acids and their salts of one metal, the ratio of the oxygen to the other con- 
 stituents may be satisfactorily expressed by monobasic formulte, in which the oxygen is 
 expressed not as a multiple of 16, but as a multiple of 8. Thus sulphurous acid and 
 
 sulphite of sodium may be formulated as follows : HS 7 3 x 8 , and NaS^O 3 x 8 , respec- 
 tively. But as we have before observed, the distinctions between monobasic and di- 
 basic acids and their salts are very decided ; and inasmuch as these acids and salts are 
 indisputably dibasic (see ACIDS), their molecules cannot be correctly represented by 
 monobasic formulae. The simplest dibasic formulae for carbonates, sulphites, and sul- 
 phates respectively, are the following, in which the proportion of oxygen is necessarily 
 1 a multiple of 16 parts : 
 
ATOMIC WEIGHTS. 463 
 
 H 2 C0 3x16 H-S*O 3x!<i H 2 S*0 4x16 
 
 CaHC0 3xla NaHS*0 3xIU KHS*0 4x18 
 
 Ca 2 CO 3xls Na 2 S*0 3xltf K 2 S*0 4x18 
 
 MgCaCO 3 x 16 NH 4 NaS * O 3 x ' NiKS * O 4 x 16 
 
 Many chemists, who acknowledge that the molecule of water consists of 2 parts of 
 hydrogen united with 16 pts. of oxygen, and that, in ninety-nine cases out of a 
 hundred, the smallest quantity of oxygen that can enter into the composition of a well- 
 defined molecule must be represented by 16 parts, prefer, from old association, to 
 accord to oxygen the atomic weight 8, and to admit that all oxygenated molecules 
 contain two inseparably associated atoms of oxygen, or some multiple of two inseparably 
 associated atoms. Thus, they represent water by the formula H 2 2 x 8 instead of H 2 0, 
 and nitric acid by HNO 6 x 8 instead of HNO 3 , &c. This practice is evidently most 
 inconsequent : for the conception of two inseparable proportions of 8 each, amounts 
 after all to that of one indivisible proportion of 16, that is to an atomic proportion of 
 16. To be consistent, we must represent the molecules of hydrochloric acid, water, 
 ammonia, and marsh-gas either by Gerhardt's atomic, or by Dalton's equivalent 
 formulae, thus : 
 
 HC1 1 * M '5 Hydrochloric acid HOP * 35>s 
 
 H 2 ixi6 Water HO 1 * 8 
 
 H 3 N * 14 Ammonia HN 1 * 4 ' 7 
 
 H 4 C 1X12 Marsh-gas EC 1 * 3 
 
 except that Dalton took, not marsh-gas, but olefiant-gas, for his standard hydrocarbon, 
 and accorded to it the formula HC 1 x 6 , whereby marsh-gas became H 2 C 1 x 6 . Now-a- 
 days we know that the molecules of marsh-gas and olefiant-gas both contain the same 
 number of hydrogen- atoms, and that their formulae are C 1 x 16 H 4 and C 2 x 16 H 4 respec- 
 tively. 
 
 With regard to chlorin e, all chemists are agreed that 35-5 parts of that element, or 
 the quantity thereof which unites with 1 part of hydrogen to form hydrochloric acid, is 
 the smallest quantity of chlorine that can enter into a combination. We find that 
 35*5 parts of chlorine are capable of directly displacing 1 part of hydrogen in a great 
 variety of compounds ; that in all well defined molecules, the quantity of constituent 
 chlorine must be represented by 35 - 5, or some multiple of 3 5 '5 parts ; that whenever 
 two bodies differ from one another in composition by the quantity of chlorine they 
 respectively contain, the difference amounts to 35'5, or some multiple of 35 - 5 parts ; 
 and that it is impossible to add to, subtract from, or displace in any compound a pro- 
 portion of chlorine which is not represented by 3o - 5, or some multiple of 35*5 parts. 
 
 In the course of the preceding observations, reference has occasionally been made to 
 the principle of analogy as a guide in determining the molecule of a compound body, 
 and the atomic weights of its constituent elements. Thus we have referred to the 
 analogy of triethylamine with ammonia, and to that of lime or oxide of calcium with 
 water or oxide of hydrogen. But, in addition to the arguments already used, we 
 may show more especially that the principle of analogy is in favour of the atomic 
 weights and molecules which we have adopted. Thus the indisputable analogies of 
 nitrous acid, nitric acid, and peroxide of nitrogen, with chlorous acid, chloric acid, 
 and peroxide of chlorine respectively, are shown very clearly by formulae in which 
 N = 14, whereas they would be concealed by formulae in which N = 4 '7, as seen 
 below : 
 
 Chlorous acid, HC10 2 HNO 2 Nitrous acid HN 3 2 
 
 Chloric acid, HC10 3 HNO 3 Nitric acid HN 3 3 
 
 Perchloric oxide, C1 2 4 N 2 4 Pernitric oxide. N 6 4 
 
 Again, with the molecule of water = 9, the relation of water to the alcohols as the 
 undoubted vanishing term of the series, would not be manifested as it is with the 
 molecule =18. Thus, if we write alcohol C 2 H 6 2 x 8 , wood-spirit CH 4 2 x 8 , and water 
 HO 1 x8 , the relation of water to the alcohols does not appear, but in the following 
 series of formulae with = 16, it is perfectly apparent : 
 
 C 5 H 12 0, Amylic alcohol C 2 H 6 0, Ethylic alcohol 
 
 C 4 H 10 0, Butylic CH 4 0, Methylic 
 
 C 3 H 8 0, Propylic H 2 0, Hydric 
 
 The relation of water to the alcohols, as shown in the above formulae, is not a mere 
 paper relation, but has its foundation in experiment. When water and alcohol re- 
 spectively are acted upon by potassium, by chloride of benzoyl, by pentachloride of 
 phosphorus, and by a host of other reagents, the reactions are acknowledged by all to 
 be precisely similar. All chemists, no matter what the formulae they employ, recognise 
 the fact that the quantity of water which in a reaction corresponds to one proportion 
 of alcohol, must contain two units of hydrogen. Similarly, with regard to hydrated 
 
464 
 
 ATOMIC WEIGHTS. 
 
 bases and acids. The reactions of the bodies clearly show that the quantity of water 
 which corresponds to one proportion of hydrate of potassium, or of hypochlorous acid, 
 for instance, must contain two units of hydrogen. If we write hydrate of potassium 
 KH0 2x8 , hypochlorous acid HC10 2x8 , and water HO 1 x8 , the formulae do not repre- 
 sent comparable quantities. But, in the following series of formulae with = 16, the 
 relations of the bodies are rendered perfectly evident : 
 
 KKO, Oxide of potassium HC10, Hypochlorous acid 
 
 KHO, Hydrate of potassium C1C10, Hypochlorous anhydride 
 
 HHO, Water KC10, Hypochlorite of potassium 
 
 Moreover the principle of analogy is frequently allowed to overrule all other con- 
 siderations. Thus the smallest quantity of aluminium that can enter into a combi- 
 nation is 27 '5 times as great as the smallest quantity of hydrogen. This quantity of 
 aluminium, like 14 parts of nitrogen, is capable of uniting with 3 atoms of chlorine, and 
 of its representatives. But, from the strong analogy existing between aluminic and 
 ferric compounds, the atomic weight of aluminium is fixed at 13 '75, in order that its 
 compounds may be represented by formulae which, though more complex than those 
 with Al = 2 7 '5, are in accordance with the formulae of corresponding ferric compounds, 
 thus: 
 
 Fe 2 Cl 3 , 
 
 KFe*(S0 4 ) 2 . 12H 2 0, 
 
 HFe 8 2 , 
 
 A1 8 CP, 
 
 KA1 2 (S0 4 ) 2 .12H*0, 
 
 HA1 2 2 , 
 
 Sesquichloride of iron 
 Iron alum 
 Brown haematite 
 Sesquichloride of aluminium 
 Common alum 
 Diaspore 
 
 The principle of analogy frequently enables us to determine satisfactorily the 
 molecules and atomic weights of bodies with which we are comparatively but little 
 acquainted. Thus the analogy of selenium and tellurium compounds, in so far as they 
 are known, to the well-known compounds of sulphur, requires us to give similar 
 formulae to the similar compounds of all three elements. With regard to sulphur 
 itself, precisely the same reasons that induce us to represent water by the formula 
 H 2 0, and to accord to oxygen the atomic weight 16, must induce us to represent sul- 
 phydric acid by the formula H 2 S, and to accord to sulphur the atomic weight 32. But 
 even if our acquaintance with sulphur were much less intimate than it is, still the 
 analogy of its best known compounds with those of oxygen would suffice to allow of a 
 satisfactory determination of its atomic weight. The principle of analogy induces us 
 to accord to the primary hydrides and chlorides of the more or less electronegative 
 elements, the following formulae, and to classify them in four principal groups, thus : 
 Monatomic. Diatomic. Triatomic. 
 
 HF H 2 H 3 N 
 
 HC1 H 2 S H 8 P 
 
 HBr H 2 Se H'As 
 
 HI EPTe H 3 Sb 
 
 cii CPO cm 
 
 C1 2 S C1 3 P 
 
 CPAs 
 CPSb 
 Cl 3 Bi 
 
 The following table represents the atomic weights of the elementary bodies on the 
 hydrogen scale (H = 1) as determined by the preceding considerations. Those on the 
 oxygen-scale (0 = 100), which are now but little used, may be found by multiplying the 
 
 hydrogen-numbers by -y^ or 6-25. The actual determinations of the atomic weights 
 are given, with the methods of quantitative estimation, under each element. 
 
 TABLE OF ATOMIC WEIGHTS. 
 
 Tetratomic. 
 
 H 4 C 
 H*Si 
 C1 4 C 
 
 ci 4 si 
 
 Cl 4 Sn 
 
 Name. 
 
 Sym- 
 bol. 
 
 Atomic 
 Weight. 
 
 Formula of Compound 
 analysed. 
 
 According to Experi- 
 ments by 
 
 Aluminium 
 
 Al 
 
 1375 
 
 Chloride of aluminium, A12CP 
 
 Dumas. 
 
 Antimony 
 
 Sb 
 
 120-3 
 122 
 
 Trisulphide, Sb 2 S3 
 Trichloride, SbCl 3 
 
 Schneider. 
 Dumas. 
 
 Arsenic .... 
 
 As 
 
 75 
 
 AsC13 
 
 Felouze, Berzelius. 
 
 Barium .... 
 
 Ba 
 
 68-6 
 
 Chloride, Bad 
 
 Marignuc, Pelouze, 
 
 Bismuth .... 
 
 Bi 
 
 210 
 
 BiCP 
 
 Dumas. 
 
 Boron .... 
 
 B 
 
 11 
 
 f Boric anlmlrido, IJ 2 O 3 
 t chloride, BC1 3 
 
 Berzelius. 
 Dumas. 
 
ATOMIC WEIGHTS. 
 
 465 
 
 TABLE continued. 
 
 Name. 
 
 Sym- 
 bol. 
 
 Atomic 
 Weight. 
 
 Formula of Compound 
 analysed. 
 
 According to Experi- 
 ments by : 
 
 Bromine .... 
 
 Br 
 
 80 
 
 Bromide of potassium, KB 
 
 Marignac. 
 
 Cadmium .... 
 
 Cd 
 
 Ca 
 
 56 
 20 
 
 Oxide, Cd 2 O 
 
 f imf Pa^O 
 
 Von Hauer. 
 
 Carbon .... 
 
 C 
 
 12 
 
 ijime, ^a \j 
 Carbonic anhydride, CO 2 
 
 f Dumas and Stas. 
 I Erdmann and Marchand 
 
 Cerium 
 
 Ce 
 
 46 
 
 Cerous oxide, Ce 2 O 
 
 Marignac, Hermann. 
 
 
 
 
 t Chloride ol potassium 
 
 Marignac, Penny ; Mau* 
 
 Chlorine 
 
 n 
 
 35-5 
 
 } 
 
 
 
 
 
 ( silver 
 
 Dumas. 
 
 Chromium 
 
 Cr 
 
 26-2 
 
 Chromic anhydride, Cr 2 O 3 
 
 Peligot, Berlin. 
 
 Cobalt .... 
 
 Co 
 
 29-5 
 
 Chloride, CoCl 
 
 Dumas. 
 
 Columbium or Niobium 
 
 Cb 
 
 976 
 
 Tetrachloride, CbCl 4 
 
 H. Rose. 
 
 Copper .... 
 Didymium 
 
 Cu 
 Di 
 
 31-7 
 
 48 
 
 Cupric oxide, Cu <2 O 
 Oxide, Di 2 O 
 
 Erdmann and Marchand. 
 Marignac. 
 
 Erbium .... 
 
 E 
 
 
 
 
 Fluorine .... 
 Glucinum 
 
 F 
 Gl 
 
 19 
 
 f 47 
 1 7-0 
 
 < Fluoride of calcium, CaF 
 \ sodium, NaF 
 Glucina, G1 2 O 1 
 OHO 3 t 
 
 Louyet. 
 Dumas. 
 
 Awdejew. 
 
 Gold .... 
 
 Au 
 
 196 
 
 Auric chloride, AuCl 3 
 
 Levol, Berzelius. 
 
 Hydrogen 
 
 H 
 
 
 Water, H 2 O 
 
 Dumas ; Erdmann and 
 
 
 
 
 
 Marchand. 
 
 Iodine .... 
 Iridium .... 
 
 I 
 Ir 
 
 127 
 986 
 
 f Iodide of potassium, KI 
 ( silver, Agl 
 Dichloride, IrCl 2 
 
 Marignac. 
 Dumas. 
 Berzelius. 
 
 
 
 
 
 5Svani:erg and Norlin. 
 
 
 
 
 t Ferric oxide, Fe 4 O 3 
 
 Maumene, Erdmann and 
 Marchand. 
 
 Iron . . 
 
 Fe 
 
 28 
 
 j 
 
 Berzelius. 
 
 
 
 
 ' Ferric chloride, Fe 2 Cl 3 
 
 Dumas. 
 
 Lanthanum . . 
 
 La 
 
 46 
 
 Oxide, La 2 O 
 
 Marignac. 
 
 Lead .... 
 
 Pb 
 
 103-6 
 
 Pb 2 O 
 
 Berzelius. 
 
 Lithium .... 
 
 Li 
 
 6-5 
 t 7-0 
 
 f Li*0 
 
 I Carbonate. I^CO 3 
 Sulphate, Li 2 S0 4 
 
 Troost. 
 Mallet. 
 
 Magnesium 
 
 Mg 
 
 12 
 
 f Magnesia, Mg-O 
 \ Chloride, MgCI 
 
 Berzelius. 
 Dumas. 
 
 Manganese 
 
 Mn 
 
 27-6 
 
 MnCl 
 
 Berzelius. 
 
 Mercury .... 
 
 Hg 
 
 100 
 
 Mercuric oxide, Hg 2 O 
 
 Erdmann and Marchand. 
 
 Molybdenum . 
 
 Mo 
 
 r 
 
 Molybdic anhydride, Mo 2 O 3 
 
 Svanberg and Strure ; 
 Berlin. 
 
 
 
 I 48 
 
 
 
 Dumas. 
 
 Nickel .... 
 
 Ni 
 
 ( 29 
 \ 29-5 
 
 Oxide, Ni'O 
 Chloride, NiCl 
 
 Schneider. 
 Dumas. 
 
 Nitrogen .... 
 Osmium .... 
 
 N 
 Os 
 
 14 
 
 100 
 
 Sal-ammoniac, NH"C1 
 Dichloride, OsCl 2 
 
 Pelouze, Marignac, Penny. 
 Berzelius, Fremy. 
 
 Oxygen .... 
 Palladium 
 
 O 
 Pd 
 
 16 
 53 
 
 Chloride, PdCl 
 
 Berzelius. 
 
 Phosphorus . . 
 
 P 
 
 31 
 
 f Phosphoric anhydride, P 2 O 5 
 1 Pentachloride, PCI 5 
 
 Schrotter. 
 Dumas. 
 
 Platinum .... 
 
 Pt 
 
 99 
 
 Dichloride, PtCl 2 
 
 Berzelius, Andrews. 
 
 
 
 ( 39 
 
 Chloride, KC1 
 
 Marignac, Fremy, Mau- 
 
 Potassium . . . 
 
 K 
 
 3 
 
 
 mene. 
 
 
 
 1 39-2 
 
 B 
 
 Stas. 
 
 Rhodium .... 
 
 Rh 
 
 52 
 
 Se'squichloride/Rh'Cl 3 
 
 Berzelius. 
 
 Ruthenium 
 
 Ru 
 
 52 
 
 
 Claus. 
 
 Selenium .... 
 
 Se 
 
 79 
 
 Selenide of 'mercury, Hg 2 Se 
 
 Berzelius, Sacc, Erdmann 
 
 
 
 
 
 and Marchand. 
 
 Silicon .... 
 
 Si 
 
 2S 
 
 Chloride, SiCl 4 
 
 Dumas. 
 
 Silver .... 
 
 Ag 
 
 108 
 
 AgCl 
 
 Marignac, Maumenfe, 
 
 
 
 
 
 Penny, Berzelius 
 
 Sodium ... 
 
 Na 
 
 23 
 
 NaCl 
 
 Penny, Pelouze, Dumas. 
 
 Strontium 
 
 Sr 
 
 43-8 
 
 SrCl 
 
 Dumas. 
 
 
 
 
 ( Cinnabar, Hg 2 S 
 
 Erdmann and Marchand, 
 
 Sulphur .... 
 
 s 
 
 32 
 
 
 Struve. 
 
 Tantalum . . . 
 
 Ta 
 
 137-6 
 
 (Sulphide of silver, Ag'-'S 
 Tetrachloride, TaCl 4 
 
 Dumas. 
 H. Rose. 
 
 Tellurium 
 
 Te 
 
 128 
 
 Bromide of potassium and tel- 
 
 
 
 
 
 lurium, K 2 TeBr 
 
 v. Hauer. 
 
 Terbium .... 
 
 Tr 
 
 
 
 
 Thorinum 
 
 Th 
 
 59-6 
 
 Thorina, Th 2 O 
 
 Berzelius. 
 
 Tin 
 
 Sn 
 
 f 116 
 
 Stannic oxide, SnO 2 
 
 Mulder, Vlaanderen. 
 
 
 
 \ 118 
 
 chloride, SnCl 4 
 
 Dumas. 
 
 Titanium .... 
 
 Ti 
 
 1 50 
 
 Tetrachloride, TiCl 4 
 
 Pierre. 
 
 Tungsten 
 Uranium .... 
 
 W 
 U 
 
 92 
 60 
 
 Tungstic anhydride, W 2 O 3 
 Uranic oxide, U 4 O 3 
 
 Schneider, Birch, Dumas. 
 Peligot. 
 
 Vanadium 
 
 V 
 
 68'5 
 
 Vanadic anhydride, V 2 O 3 
 
 Berzelius. 
 
 Yttrium .... 
 
 Y 
 
 
 
 
 Zinc . ... 
 
 Zn 
 
 32-5 
 
 Oxide, Zn 2 O 
 
 A. Erdmann. 
 
 Zirconium 
 
 Zr 
 
 < 33-5 
 
 t 895 
 
 Zirconia, ZHO 3 > 
 
 Berzelius, Erdmann. 
 
 We will now turn our attention to the determination of atomic weights from 
 physical considerations, and observe how far the weights deduced from physical and 
 chemical considerations coincide with one another. In tho first place then, we will dis- 
 
 VOL. I. H II 
 
466 ATOMIC WEIGHTS. 
 
 cuss the combining volumes of gases and vapours- from the observation of 
 which we derive the most important of all means for controlling our conclusions as to 
 the atomic weights of volatile bodies. If we take the specific gravity of hydrogen gas as 
 unity, we find experimentally that the specific gravities of most other elementary gases 
 and vapours are represented by the numbers we have selected to express their atomic 
 weights. Hence, these atomic numbers represent the weights of equal volumes of 
 the respective gases and vapours; and the formula of a compound body shows the 
 number of elementary volumes of which it is composed. Thus while the formula for 
 nitric acid HNO 3 represents a compound of one part of hydrogen, fourteen parts of 
 nitrogen, and three times sixteen parts of oxygen, it also represents a compound of onn 
 volume of hydrogen, one of nitrogen, and three of oxygen. The relative specific 
 .gravities of the following elements, when in the gaseous state, and exposed to the 
 same pressure and temperature, have been ascertained to be respectively : 
 
 H = 1 Cl = 35-5 = 16 N = 14 
 
 Hg = 100 Br = 80 S - 32 P = ^ 
 
 Cd = 56 I = 127 Se=r 79-5 As = Tf 
 
 Hydrochloric acid gas is composed of one volume of hydrogen, and one volume of 
 chlorine united without any condensation. Consequently the molecule of hydrochloric 
 acid is represented by two volumes of gas QD , whilst the atoms of hydrogen and 
 chlorine respectively are represented by one volume only n. Hence while the 
 specific gravity, or weight of a unit of volume of chlorine coincides with its atomic 
 weight, the specific gravity or weight of a unit of volume of hydrochloric acid coin- 
 cides with the half of its atomic weight, = 18*25. Now ninety-nine percent. 
 
 of all known volatile compounds agree with hydrochloric acid in this particular, 
 namely, that their specific gravities in the gaseous state are the halves of their atomic 
 weights. Thus the atomic weight of water JFO 1 x 16 , being 18, one volume of steam 
 is found to be 9 times as heavy as one volume of hydrogen. The atomic weight of 
 ammonia, H'N 1 x 14 , being 17, one volume of ammoniacai gas is found to be 8-5 times 
 as heavy as one volume of hydrogen. The atomic weight of marsh-gas, IFC 1 x r2 , 
 being 16, one volume of the gas is found to be 8 times as heavy as one volume of 
 hydrogen, and so forth. Inasmuch, therefore, as half the atomic weight coincides 
 with the specific gravity, or weight of one unit of volume, the entire atomic weight 
 must represent twice the specific gravity or the weight of two units of volume; a con- 
 clusion which may be confirmed by actual experiment. Thus one volume of oxygen, 
 and two volumes of hydrogen at the temperature 100 C. can be converted into two 
 volumes of steam at the temperature 100. Again two volumes of ammonia, when 
 decomposed by the transmission of a series of electric sparks, yield one volume of 
 nitrogen, and three volumes of hydrogen. No matter what the number of atoms or 
 volumes which enter into the constitution of any volatile compound, they all become 
 condensed into two volumes, as shown by the fact that the specific gravity or vapour- 
 density of the compound is the half of its atomic weight. 
 
 Seeing that the molecule of a compound body corresponds with two volumes of gas 
 or vapour, and the atom of an element with but one volume, it is evident that the 
 quantity of an element which is strictly comparable to the molecule of a compound body 
 must be represented by two atoms. Hence the symbols | H I H j , |H| cl"|, and jTTJci', 
 represent comparable quantities of the three bodies, hydrogen, hydrochloric acid, 
 and chlorine respectively which, thus formulated, present an obvious relation of 
 sequence to one another. By the molecule of an element, therefore, we invariably 
 understand two atoms or two volumes; and there is great reason to believe that our 
 acquaintance with the uncombined elements pertains exclusively to their molecules. 
 So that while Cl, for instance, represents the atom, or smallest proportion of chlorine 
 that can enter into a combination, Cl 2 represents the molecule or smallest proportion 
 of free chlorine that can result from or effect a reaction. There are certain com- 
 pound molecular groupings also, which like the elementary molecules, occupy two 
 volumes when in the free state, and become halved in combination. Thus ethyl in the 
 free state is represented by C 4 H 10 = DC? , in the combined state by C 2 H 5 = Q , and 
 so in other instances. 
 
 It is evident from the preceding observations that, in the great majority of instances, 
 the molecules we have deduced from chemical considerations, are identical with the 
 molecules deduced from the physical law of gaseous volumes enunciated by Ampere, 
 namely, that all gases contain the same number of molecules within the same volume. 
 But if we had represented water by the formula HO 1 x 8 , sulphydric acid by the 
 formula ITS 1 * 16 , and carbonic oxide by the formula C lx6 lx8 , we should have 
 represented their molecules as having only half the volume of the molecule of hydro- 
 chloric acid, and should consequently have violated Ampere's physical law. The 
 
ATOMIC WEIGHTS. 467 
 
 general conclusions at which we have arrived, however, namely that the chemical atoms 
 of elementary bodies correspond with one gaseous volume, and the chemical molecules 
 of simple or compound bodies, with two gaseous volumes, is quite in accordance with 
 physical requirements. Nevertheless there are some exceptions, real or apparent, to 
 which we must now direct our attention. We may premise by saying that some 
 chemists attach so great an importance to the law of volumes, that they would be 
 guided exclusively by it, and would accord to all bodies whatsoever, such atomic 
 weights as would be in accordance with it. In the present state of knowledge, however, 
 it seems to us preferable to deduce the chemical atom or molecule of a body chiefly 
 from chemical considerations, and to wait for further investigation to clear up the few 
 anomalies which at present exist between the results of chemical and physical inquiry. 
 Certain apparent exceptions to the law of volumes have of late years been satis- 
 factorily explained away, by having regard to the following habitudes of volatile 
 bodies. In the first place, some vapours, at temperatures but little raised above their 
 condensing points, have anomalous densities which are much too high, or, in other 
 words, the volumes of their atomic proportions are much too small ; whereas at higher 
 temperatures their densities and volumes are perfectly normal. Thus at a temperature 
 a little above its condensing point, an atomic proportion of sulphur vapour occupies 
 only | the bulk of an atomic proportion of hydrogen gas at the same temperature ; but 
 at the temperature 1000 C. the two atomic proportions .occupy the same volume. 
 Again the molecule of acetic acid vapour at the temperature 230 C. has the same 
 volume as the molecule of hydrochloric acid gas at that temperature ; but at lower 
 temperatures, its volume decreases almost to one-half that of hydrochloric acid gas at 
 the same temperatures. In reference to this property it must be borne in mind that 
 vapours near their condensing points manifest variations from several of the physical 
 laws affecting gases. It would seem, indeed, that a vapour must be heated to a tem- 
 perature considerably above its condensing point before it acquires the properties of a 
 perfect gas. The recognition of this circumstance enables us to account in several 
 instances for those departures from Ampere's law, in which the density of the gas is 
 too high. In the second place, several compounds at the high temperatures required 
 to bring them into a perfectly elastic state, seem to undergo a change, which has been 
 investigated by Kopp, Marignac, Deville, Hofmann, Kekule and others, and has been 
 termed disassociation. According to these investigators, the molecule of a volatile 
 compound, when strongly heated, sometimes breaks up into two simpler molecules 
 which, on a reduction of temperature, reunite to form th<) original body, so that at 
 the temperature at which the density is taken, we are really operating, not upon one 
 more complex, but upon two less complex molecules ; whence the densities are found to 
 correspond with four volumes of vapour instead of with only two. The anomalous 
 volumes or densities of the following compounds have been explained in this way. 
 
 4Vols 2 Vols. 2Vols. 
 
 Sal-ammoniac NIFC1 = NH 3 + HC1. 
 
 Sulphuric acid H 2 S0 4 = SO 3 + H 2 O. 
 
 Pentachloride of phosphorus . . PCI 5 = PCI 3 + Cl 2 . 
 
 Hydrate of ethylendiamine . . . C 2 H 10 N 2 = C 2 H 8 N 2 + H 2 0. 
 The phenomenon of disassociation then frequently enables us to explain various 
 departures from Ampere's law, in which the densities are too low ; or in which, in 
 other words, the volumes are too great. But there still remain certain exceptions, 
 which, in the present state of knowledge, cannot be satisfactorily explained by either 
 of the above described considerations. Thus the atomic volumes of the vapours of 
 phosphorus and arsenic respectively, are only one-half that of hydrogen. In order to 
 make their atomic weights correspond with their atomic volumes, the ordinarily re- 
 ceived atomic weights would have to be doubled, whereby they would become 62 and 
 150 respectively. But this doubling of the atomic weights of phosphorus and arsenic 
 would be in violation of all chemical considerations, and likewise of all physical consi- 
 derations except that relating to the atomic volumes of the elements themselves. Thus 
 the formula for phosphamine would become P lx62 H 6 , and that, for arsenamine 
 As lxl50 H 6 , despite the analogy of the two compounds to ammonia NH 3 , and despite 
 the fact that the hydrogen of the two compounds is divisible into thirds only and 
 not into sixths. Moreover the vapour-densities of the compounds P J X 62 H 6 an( j 
 As lxl50 H 6 would correspond to 4 volumes instead of 2, and would consequently be 
 in opposition to Ampere's law. Again, the atomic heats of phosphorus and arsenic 
 corresponding to the atomic weights 62 and 150 respectively, would be twice as high 
 as the highest atomic heat of any other element. Lastly, by doubling the atomic 
 weights of arsenic and phosphorus, the isomorphism of certain compounds of ammonia 
 with the corresponding compounds of phosphamine and arsenamine would become 
 unintelligible. At present then we are forced to admit that the vapour-densities of the 
 elements, phosphorus and arsenic, are anomalous, and that we are incapable of ex- 
 
 ii n 2 
 
468 ATOMIC WEIGHTS. 
 
 plaining the cause of the anomaly. It may be that the vapours of these elements, 
 Hke that of sulphur, though anomalous at one temperature, become normal at a 
 higher temperature, though it must be admitted that the recent experiments of Deville 
 do not countenance such an expectation. Or it may be that the anomalies depend 
 upon allotropy. Phosphorus and arsenic are known to exist in different allotropic 
 conditions, and it is not improbable that each allotropic form may have a different 
 atomic weight. Hence the anomaly might be explained by supposing that phospha- 
 mine, for instance, contains the element phosphorosum, having the atomic weight 31 ; 
 whilst phosphorus-vapour is composed of the element phosphoricum, having the 
 atomic weight 62. This supposition of vapour-allotropy might also serve to explain 
 the anomolous vapour-density of acetic acid at a low temperature. Normal acetate of 
 potassium has the formula O'IPKG 2 , but there is also an acid-acetate having the 
 formula C 4 H 7 KO 4 . The small vapour-density might possibly represent an acetic acid 
 corresponding to the former salt, and the high vapour-density an acetic acid corre- 
 sponding to the latter. 
 
 Certain other real or apparent exceptions to the law of volumes, are afforded by the 
 chlorides and ethylides of zinc, mercury, and some other metals, as indicated below : 
 
 Hydrochloric acid . . . HC1 = 2 vols. 
 
 Hydride of ethyl . . . HEt 
 
 Chloride of ethyl . . . ClEt 
 
 Chloride of mercury . . . HgCl = 1 vol. or Hg 2 Cl 2 = 2 vols. 
 
 Ethylide of mercury . . . HgEt HgW 
 
 Ethylide of zinc .... ZnEt Zn 2 Et ? 
 
 Methylide of zinc . . . ZnMe,, ., Zn 2 Me 2 
 In consequence of the anomalous vapour-densities of the molecules of these com- 
 pounds, as above expressed, some chemists have proposed to double the ordinarily 
 received atomic weight of the metals mercury and zinc, so as to represent the molecules 
 of the above volatile compounds by the following 2-volume formulae ; and it must be 
 acknowledged that very strong reasons may be urged in favour of the duplication : 
 Chloride of mercury . . . CFHg 1 * 20 " 
 
 Ethylide of mercury 
 Ethylide of zinc 
 Methylide of zinc 
 
 corresponding to j^f 1 " 80 ^- 
 
 Et'Hg 1 * 200 
 Et'Zn 1 * 65 
 Me'Zn'* 65 
 
 It is admitted both by those who advocate and those who deprecate the proposal, that 
 the duplication of the atomic weights of the metals mercury and zinc, would necessi- 
 tate the duplication of the atomic weights of several other metals, including magnesium, 
 cadmium, lead, copper, iron, chromium, and aluminium. Now the principal objections 
 to the adoption of this proposal are the following. Firstly, because, although the 
 duplication of the atomic weights of the metals would bring the volumes of their 
 chlorides and ethylides into accordance with Ampere's law, it would bring the volumes 
 of the elements themselves into discordance. therewith. Thus, the atomic volumes of 
 mercury and cadmium corresponding to the atomic weights 200 and 112 respectively, 
 would each be twice as great as the atomic volume of any other element. Secondly, 
 because the chlorides, oxides, &c., of these metals, which are ordinarily represented 
 as proto-compounds, would have to be represented as deuto-compounds, thus 
 HgCl 2 , ZnCl 2 , CdCl 2 , &c., a result not warranted by chemical considerations, seeing that 
 in their chemical properties, these compounds are quite undistinguishable from undis- 
 puted proto-compounds. Moreover, the adoption of these doubled atomic weights 
 would lead to most complex expressions for very many compounds. Of course, if it 
 could be proved that the true atomic weights of these metals were really the doubles of 
 those ordinarily employed, the circumstance of the duplication leading to inconvenient 
 formulae would have to be disregarded ; but in the absence of such proof, the com- 
 plexity to which the conclusion would lead is pro tanto evidence against the proba- 
 bility of its being true. Thus, phosphate of lead would become Pb" 3 P 2 8 instead of 
 Pb 3 PO 4 ; potassio-sulphate of copper would beecome K 2 Cu"(S0 4 ) 2 .6H 2 instead of 
 KCuS0 4 .3H 2 0; sulphovinate of zinc would become Et 2 Zn"(SO')-.2H 2 O instead of 
 EtZnSO 4 .H 2 0; mercaptide of mercury would become Et 2 Hg"S 2 instead of EtIIgS, &c. &c. 
 Other exceptions to Ampere's law are furnished by the sesquichlorides of aluminium, 
 iron, and chromium, the vapour densities of each of which, as determined by Deville, 
 correspond to one volume of vapour only, instead of to two volumes. Hence it has been 
 proposed to double the weights of the molecules of these compounds, and to represent 
 them by the formulae Al'Cl 6 , JVCl 6 , and Cr 4 Cl a respectively. But it is observable 
 that if the molecule of sesquichloride of aluminium really contains 6 atoms of chlorine, 
 it must also contain 55 parts of aluminium, and as a consequence, 55 parts of alumi- 
 
ATOMIC WEIGHTS. 
 
 469 
 
 nium will constitute the smallest combining proportion of the metal, or the smallest, 
 quantity which ever exists in a combination ; in which case the smallest combining pro- 
 portion of aluminium will have twice the specific heat of the smallest combining propor- 
 tion of any other element, a result that must throw considerable doubt upon the 
 propriety of the change on which it would be consequent. Again the vapour-density 
 and chemical relations of chlorochromic aldehyde alike show that its molecule must 
 be expressed by the' formula Cr 2 2 Cl 2 ; while the correlations of sesquichloride of 
 chromium and chlorochromic aldehyde require the molecules of the two compounds to 
 be represented by formulae expressing the same amount of chromium, which would not 
 be the case if the sesquichloride were represented by the formula Cr*Cl 8 . There is, 
 moreover, another compound, namely, arsenious anhydride, As 8 3 , the vapour-density 
 of which corresponds to only one volume of vapour instead of two volumes, although no 
 reason for the anomaly has yet been brought forward. There are also three well- 
 known compounds, the vapour-densities of each of which correspond to four volumes, 
 instead of to only two, namely, nitric oxide, N 2 2 , pernitric oxide, N 2 4 , and perchloric 
 oxide, C1 2 4 . In its chemical relations, the molecule of nitric oxide, N 2 2 , corresponds 
 to the molecule of chlorine, Cl 2 , and the atom of nitric oxide, NO, corresponds to the 
 atom of chlorine, Cl : but whilst the atom of chlorine corresponds to one volume, and 
 the molecule of chlorine to two volumes, the atom of nitric oxide corresponds to 
 two volumes, and its molecule to four volumes of gas, and similarly with pernitric 
 oxide and perchloric oxide. At present no satisfactory explanation has been given 
 of these anomalies, though it is not improbable that they may be explicable on 
 the principle of disassociation. Thus, it is possible that the atom of sulphurous 
 anhydride, (SO 2 )", which, like that of oxygen, O", is capable of displacing two atoms of 
 hydrogen, would also, like the atom of oxygen, be represented by one gaseous volume, 
 were it not for the circumstance that the molecule of oxygen, O 2 , cannot split into two 
 other molecules, whereas the molecule of sulphurous anhydride, S 2 4 , corresponding 
 thereto in equivalency, can split into two separate molecules, each of which is capable 
 of occupying two volumes ; and this relation of oxygen to the diequivalent atoms of 
 sulphurous anhydride, sulphuric anhydride, carbonic oxide, carbonic anhydride, &c., 
 may be a parallel of the relation which subsists between chlorine and the prot- 
 equivalent atoms of nitric oxide, pernitric oxide, and perchloric oxide respectively. 
 
 Out of many hundred volatile bodies whose vapour-densities have been ascertained, the 
 following table comprises all the well-known exceptions to Ampere's law, though doubt- 
 less the strict chemical analogues of some of these bodies would also prove exceptional : 
 
 Symbol. 
 
 Vapour. 
 
 Atomic 
 weight. 
 
 Theore- 
 tical 
 volume. 
 
 Actual 
 volume. 
 
 P 
 
 Phosphorus 
 
 P = 31 
 
 1 
 
 1 
 
 As 
 
 Arsenic 
 
 As = 75 
 
 I 
 
 I 
 
 ITgCl 
 
 Corrosive sublimate 
 
 Hg =100 
 
 2 
 
 1 
 
 HgEt 
 
 Mercuric ethyl 
 
 
 2 
 
 1 
 
 HgMe 
 
 Mercuric methyl 
 
 
 2 
 
 1 
 
 ZnEt 
 
 Zinc-ethyl 
 
 Zn =32-5 
 
 2 
 
 1 
 
 ZnMe 
 
 Zinc-methyl 
 
 
 2 
 
 1 
 
 As-0 8 
 
 Arsenious anhydride 
 
 As =75 
 
 2 
 
 1 
 
 APC1 3 
 
 Aluminic chloride 
 
 Al =13-75 
 
 2 
 
 1 
 
 Fe-Cl 3 
 
 Ferric chloride 
 
 Fe =28 
 
 2 
 
 1 
 
 Cr-'Cl 3 
 
 Chromic chloride 
 
 Cr =26-2 
 
 2 
 
 1 
 
 N 2 2 
 
 Nitric oxide 
 
 N = H 
 
 2 
 
 4 
 
 N 2 4 
 
 Pernitric oxide 
 
 
 2 
 
 4 
 
 C1 2 4 
 
 Perchloric oxide 
 
 Cl = 35-5 
 
 2 
 
 4 
 
 H 2 S0 4 
 
 Sulphuric acid 
 
 S = 16 
 
 2 
 
 4 
 
 NH 4 C1 
 
 Sal-ammoniac 
 
 N = 14 
 
 2 
 
 4 
 
 NH'CN 
 
 Cyanide of ammonium 
 
 C = 12 
 
 2 
 
 4 
 
 NIF.H.S 
 
 Sulphydrate of ammonium 
 
 S = 32 
 
 2 
 
 4 
 
 PGP 
 CH 10 N 2 
 C 6 H 1S N 2 
 
 Pentachloride of phosphorus 
 Hydrate of ethylene-diammonuim 
 Hydrate of diethyl-ethylene-diammo- 
 
 P = 31 
 C = 12 
 
 2 
 2 
 2 
 
 4 
 
 4 
 4 
 
 
 nium 
 
 
 
 
 HH 3 
 
470 
 
 ATOMIC WEIGHTS. 
 
 The anomalous volumes of the last seven compounds are clearly explicable on the prin- 
 ciple of disassociation. With regard to the duplication of the atomic weights of those 
 metals whose chlorides and ethylides have anomalous densities, it must be remembered 
 that the proposal is at present young, and that further investigation may suffice to 
 remove some of the objections which at present surround it ; precisely as further in- 
 vestigation removed the objections which in the first instance seemed to oppose with 
 overwhelming force, Gerhardt's proposal to double the then received atomic weights of 
 carbon, oxygen, and sulphur. This same remark applies to the proposal of Cannizzaro, 
 which we shall next have to consider. 
 
 It was contended by Dulong and Petit, who were the earliest investigators on the 
 subject, that all elementary atoms have the same capacity for heat, or, in other words, 
 that the specific heats of all elementary atoms are the same. If this law 
 be admitted, it is obvious that the determination of the specific heat of an element 
 must furnish a ready means of fixing its atomic weight. The atomic heats of simple 
 and compound bodies have been of late years ascertained with great care, though from 
 the nature of the subject it can scarcely be said with great accuracy, by Kegnault, 
 whose results, corresponding to the atoms which we have adopted, are as follows : 
 
 12 
 
 32-5 
 56 
 
 1375 
 28 
 29-5 
 29-5 
 317 
 100 
 
 53 
 
 99 
 
 27-5 
 
 26-2 
 
 12 
 
 20 
 
 43-8 
 
 68-6 
 
 Carbon . 
 Zinc 
 
 Cadmium . 
 Aluminium 
 Iron 
 
 Nickel . 
 Cobalt . 
 Copper 
 Mercury . 
 Lead 
 
 .Palladium 
 Platinum 
 
 2-89 
 3-10 
 3-16 
 2-93 
 3-18 
 3-20 
 3-15 
 3-01 
 3-19 
 3-25 
 3-15 
 3-19 
 
 Chromium 
 
 Magnesium 
 
 Calcium 
 
 Strontium 
 
 Barium 
 
 80 
 
 Bromine 
 
 127 
 
 Iodine . 
 
 32 
 
 Sulphur 
 
 79 
 
 Selenium 
 
 128 
 
 Tellurium 
 
 31 
 
 Phosphorus 
 
 75 
 
 Arsenic . 
 
 120-3 
 
 Antimony 
 
 210 
 
 Bismuth 
 
 118 
 
 Tin 
 
 23 
 
 Sodium . 
 
 39 
 
 Potassium 
 
 108 
 
 Silver . 
 
 196 
 
 Gold . 
 
 674 
 6-87 
 6-48 
 6-62 
 6-06 
 5-85 
 6-10 
 6-09 
 6-57 
 6-57 
 675 
 671 
 6-16 
 6-38 
 
 The numbers representing Regnault's atomic heats were obtained by multiplying the 
 observed specific heats of the bodies, referred to that of water as unity, by their 
 atomic weights on the oxygen scale. But it would be found more convenient in prac- 
 tice to assume the atomic heat of lead, which corresponds nearly with the mean 
 atomic heat, as unity ; whereby the atomic heats of the first class of metals would 
 approximate more or less closely to the number 1, and those of the second class to 
 the number 2. On this scale, the specific heats of the first class elements would cor- 
 respond to the reciprocals of their atomic weights on either scale, and those of the 
 second class to twice their reciprocals. 
 
 At the time of Regnault's researches, the atomic weights of all the elements in the 
 second column, with the exception of sodium, potassium, and silver, were frequently 
 expressed by the halves of the numbers we hare adopted. Kegnault proposed to halve 
 the atomic weights of these three metals also, whereby the atomic heats of all the 
 elements would be in accordance with Dulong and Petit's law, and would be ex- 
 pressed by numbers approximating more or less closely to 3'0 on the water-unity 
 scale, or to 1-0 on the lead-unity scale. It is observable that in no case does the 
 experimental atomic heat thus obtained differ from the mean atomic heat in the propor- 
 tion of 1*1, or 0'9, to 1*0 ; whereas the extreme atomic weights differ from one another 
 in the ratio of 1 to 9. Concerning this close correspondence in the atomic heats of the 
 elements, Graham writes : " The law (of Dulong and Petit) would probably represent 
 the results of observation in a perfectly rigorous manner, if the specific heat of each 
 body could be taken at a determinate point of its thermometrical scale, and if the 
 specific heat could be further disencumbered of all tne foreign influences which modify 
 the observation," such as the original state of hardness or softness of the body, its 
 crystalline or amorphous condition, the heat absorbed to produce softening, and the 
 heat absorbed to produce dilatation, &c. Kecent chemical research, however, has 
 rendered it impossible for chemists to halve the atomic weights of the elements in the 
 second column, so as to make their atomic heats coincide with that of lead ; and hence 
 Cannizzaro has been led to advocate a transposition of Regnpult's proposal, so as to main- 
 tain the integrity of Dulong and Petit's law, by doubling the atomic weights of the 
 metals in the first column, whereby the atomic heats of all the elements, with the 
 
ATOMIC WEIGHTS. 471 
 
 possible exception of carbon, would be expressed by numbers approaching more or less 
 closely to 6. 
 
 Cannizzaro has also pointed out that if his atomic weights were adopted, the atomic 
 heats of many compound bodies, when divided by the number of their constituent 
 atoms, would give a number approximating more or less closely to 6, or in other 
 words, the atomic heats of these bodies approximate to the sum of the atomic heats 
 of their constituent elements. It is observable, however, that the latter mode of ex- 
 pressing the fact applies equally well, whether or not we double the atomic weights in 
 the first column. Thus the atomic heat of chloride of silver approximates to 6 + 6 
 or 12, and that of chloride of lead to 6 + 3, or 9. 
 
 It is evident that the atomic weights proposed by Cannizzaro, from considerations 
 of specific heat, frequently correspond with those which he and others have been led 
 to from considerations of atomic volume ; and their adoption is consequently liable to 
 the objections which we have already taken. 
 
 Cannizzaro' s proposal, moreover, would involve the dissassociation of silver from 
 lead, and that of the metals of the alkalis from those of the alkaline earths. The 
 chlorides of silver and potassium, for instance, would be represented as protochlorides 
 by the formulae AgCl and KC1 respectively, whilst those of lead and barium 
 would be represented as dichloridcs by the formulae PbCl 2 and Bad 2 respec- 
 tively. Now the highly basic characters of the alkaline earth-metals, the strongly 
 alkaline reactions of their dissolved hydrates, the perfect neutrality and great per- 
 manency of their salts, seem to demonstrate their analogy to undisputed protequiva- 
 lent metals, such as potassium, rather than to undisputed di-equivalent metals, such 
 as tin. Again, the large number of similar compounds to which silver and lead give 
 origin, the close resemblance in chemical properties of their corresponding compounds, 
 their very general paramorphism, and not unfrequent isomorphism, seems to forbid 
 their representation by discordant formulae. The two metals are soft, malleable, 
 fusible, volatile, and isomorphous. The two chlorides are anhydrous and insoluble, 
 or sparingly soluble ; the two sulphates are anhydrous, insoluble and similiform ; the 
 two hydrates are sparingly soluble, forming alkaline solutions ; the two sodium-double- 
 chlorides, potassium-double-iodides, protosulphides, cuprososulphides, monobasic and 
 tribasic sulphantimonites, are similar in their chemical, and isomorphous in their 
 physical relations. 
 
 It seems to us that the objections to Cannizzaro's general proposition, are, in the 
 present state of knowledge, too great to admit of its adoption ; but still it is a question 
 whether some of the metals comprised in the first column might not advantageously, 
 receive the doubles of their ordinarily admitted atomic weights. With regard to the 
 metals palladium and platinum, for instance, it is not by any means improbable 
 that their real atomic weights may prove to be 106 and 198 respectively. With 
 regard to aluminium, again, it is certain that, so far as our actual knowledge goes, the 
 smallest indivisible proportion of aluminium that can exist in a combination is twice 
 the proportion expressed by its ordinarily received atomic weight, or, in other words, 
 it amounts to 27'5, instead of to only 13*75 parts. All chemists invariably represent 
 the compounds of aluminium to contain 27 '5 parts of aluminium, which is indeed its 
 smaDest combining proportion or chemical atom. Consequently, by employing the num- 
 ber 13*75 to express the atomic weight of aluminium, all aluminous compounds have to 
 be represented as containing two inseparable atoms, or some multiple of two inseparable 
 atoms of the metal, a result which is evidently un philosophical. The chemical habitudes 
 of the metal aluminium resemble the chemical habitudes of the metal bismuth, 27 '5 parts 
 of the former corresponding to 210 parts of the latter : and there is no greater chemical 
 reason for halving the 27'5. parts of aluminium in order to represent its trichloride 
 as a sesquichloride, than there is for halving the 210 parts of bismuth in order to 
 represent its trichloride as a sesquichloride. Somewhat similar observations apply to 
 the metals, iron, manganese, and chrome, when entering into the constitution of 
 ferric, manganic, and chromic salts, respectively. Throughout all the decompositions 
 and rccompositions of ferric compounds, for instance, so long aa they continue to be 
 ferric compounds, we find 56 parts of iron constituting one indivisible combining pro- 
 portion or chemical atom. We have two allotropic forms of the metal iron, one of 
 which we call ferrosum, having the atomic weight 28, the atomic heat 3, and combin- 
 ing with 1 atom of chlorine, to form a protoehloride ; the other, which we call 
 ferricum, having the atomic weight 56, the atomic heat 6, and combining with 3 
 proportions of chlorine to form a trichloride ; and similarly with chromosum and chro- 
 niicum, manganosum and manganicum. The ferrous and ferric atoms have distinct 
 chemical properties and form distinct series of compounds, which differ more from 
 one another than do the salts of ferrosum from those of nickel and copper, or than do 
 the salts of ferricum from those of aluminium and bismuth. So great, indeed, is the 
 difference, that, had we been unacquainted with the methods of converting ferrous 
 
 11 11 i 
 
472 ATOMIC WEIGHTS. 
 
 and ferric compounds into one another, we should never have suspected them fo 
 contain the same metal, or even similar metals. Now, that two different allotropic 
 forms of the same element may have different atomic weights and different equiva- 
 lent functions, seems to be no longer questionable. Brodie's reseaches on graphon 
 have shown conclusively that compounds may be prepared which contain the graphitic 
 modification of carbon, and are altogether dissimilar from compounds containing the 
 ordinary form of carbon. In fact, ordinary carbon-compounds present a greater 
 analogy to corresponding compounds of sulphur than they do to any of the known 
 compounds of graphon, precisely as the salts of ferrosum resemble salts of nickel more 
 closely than they do the salts of ferricum. The only circumstance wanting to complete 
 the parallel is that not only carbon and graphon compounds, but isolated carbon and 
 graphon are known to chemists ; whereas, though ferrous and ferric compound's are well 
 known, chemists have not yet recognised any form of iron distinct from ferrosum, 
 unless indeed we make the by no means improbable assumption that iron in the passive 
 state constitutes ferricum. The specific heats of carbon, graphon, and diamond cor- 
 respond clearly with different atomic weights. Thus, if we accord to carbon the atomic 
 weight 12, to graphon the atomic weight 18, and to diamond the atomic weight 24, the 
 atomic heats of the three bodies, calculating from Regnault's results, will be 2*8980, 
 3*6324, and 3*5232 respectively, giving a mean of 3*3512. But it seems probable from 
 chemical considerations that the atomic weight of graphon is not 18, but 36 (33 
 Brodie), in which case its atomic heat will be 7*2048, or exactly as much above the 
 mean as that of phosphorus is below it. 
 
 Precisely as the double atoms of iron and aluminium in ferric and aluminic salts 
 constitute indivisible proportions, so do the double atoms of copper and mercury in 
 cuprous and mercurous compounds constitute indivisible proportions throughout all 
 the decompositions and recompositions of their respective salts. So long as the metals 
 remain in the state of cuprosum and mercurosum, so long do 63*5 parts of the former 
 and 200 parts of the latter constitute their respective atomic weights or smallest 
 indivisible combining proportions. Each metal would have for its atomic heat the 
 number 6, and would combine with one atom of chlorine to form a protochloride, so that 
 while the atoms of ferrosum and ferricum combine with the halogens, &e., in different 
 proportions, or, in other words, have different degrees of equivalency, the atoms of 
 mercurosum, and mercuricum though having different atomic weights and different 
 atomic heats, combine each with the same proportion of halogen, or, in other words, 
 have the same degree of equivalency ; and similarly with cuprosum and cupricum (see 
 EQUIVALENTS). A convenient mode of representing the atoms of ferricum, mercurosum, 
 &c., consists in doubling one of the letters of the respective symbols used to express 
 the atoms of ferrosum and mercuricum, &c., so as to indicate that the atoms of the 
 former elements are twice as heavy as those of the latter. In a similar manner the 
 atom of graphon might be represented by the symbol Ccc, to imply that it had three 
 times the atomic weight of carbon. In this way we might arrange the following 
 series of atoms : 
 
 Atomic heats = 3. Atomic heats 6. 
 
 Carbon . . C"" 12 Graphon . . Gr or Ccc 36 
 
 Aluminium . All'" 27*5 
 
 Ferrosum . Fe' 28 Ferricum . Ffe'" 56 
 
 Manganosum . Mn' 27 '5 Manganicum . Mm'" 55 
 
 Chromosum . Cr' 26*25 Chromicum . Ccr'" 52*5 
 
 Mercuricum . Hg' 100 Mercurosum . Hhg' 200 
 
 Cupricum . Cu' 31*75 Cuprosum . Ccu' 63*5 
 
 By thus recognising the quantities represented in the second column as distinct atoms, 
 we obtain nearly all the advantages, with scarcely any of the disadvantages, which 
 would accrue from Cannizzaro's proposal, and are enabled to account satisfactorily for 
 the frequent isomorphism or parallelism of the double proportions of these elements, 
 with the single proportions of other elements, as illustrated below : 
 
 KC10 1 withKMmO 4 instead of KMn 2 4 
 K 2 S0 4 3 2 Mm0 4 K 2 Mn 2 4 
 
 K 2 Cr 2 4 
 
 Cr 2 3 
 
 K 2 S0 4 K-CcrO 4 
 
 SO 3 CcrO 3 
 
 80 2 C1 2 Ccr0 2 Cl 2 
 
 Ag-S Ccu 2 S 
 
 Ag'SbS 3 Pb 2 CcuSbS 3 
 
 Pb-S PbCcuS 
 
 Cr 2 2 CP 
 Cu 4 S 
 
 Pb'Cu 2 SbS 3 
 PbCu 2 S 
 
 In addition to vapour-density and specific heat, isomorphism also furnishes a 
 valuable aid in the determination of atomic weights. As a rule, the isomorphism of a 
 
ATOMIC WEIGHTS ATRIPLEX. 473 
 
 comparatively unknown substance, with a substance of which the formula and atomic 
 weight are well determined, warrants us in according to the less known body a 
 formula and atomic weight corresponding to those of the better known body. Thus, 
 the isomorphism of the stannic and titanic anhydrides, of the chromate and molybdate 
 of lead, of the sulphate and selenate of sodium, assists us materially in our determi- 
 nation of the atomic weights of titanium, molybdenum, and selenium respectively, and 
 of the formulae of their respective compounds. But atomic weights deduced chiefly 
 from isomorphous considerations, require to be received with very great caution, 
 for the following reasons. We sometimes find obvious chemical analogies to exist in 
 cases, where from dimorphism, or some other cause, the isomorphism is very imper- 
 fectly developed ; and on the contrary, we sometimes have a marked isomorphism 
 existing between bodies whose chemical correlations are very unsatisfactory. Thus, 
 the isomorphism of potassium and sodium salts is not by any means striking. Nitrate 
 of potassium, for instance, usually crystallises in right rhombic prisms, and nitrate of 
 .sodium in rhomboids. It seems, however, that each salt can crystallise in both 
 systems, and that while the ordinary form of nitrate of sodium corresponds with the 
 rare form of nitrate of potassium, the ordinary form of nitrate of potassium corre- 
 sponds with the rare form of nitrate of sodium. Again, the chemical analogies of 
 similar lead and mercury compounds are extremely well marked, but isomorphism is 
 manifested in a very few instances only. Indeed the isomorphous relations of lead 
 and calcium are more decided than are the isomorphous relations of lead and mercury. 
 Again, tellurium is heteromorphous with its chemical analogues, selenium and sulphur, 
 and isomorphous with its chemical heterologues, arsenic and antimony. One might 
 here refer for a moment to the well-known isomorphism of certain sulphides and 
 arsenides. Thus, sulphide of nickel, Ni 2 S, is isomorphous with the arsenide Ni 2 As, 
 and the antimonide Ni 2 Sb. Marcasite, Fe 2 S 2 , is isomorphous with mispickel, Fe 2 SAs ; 
 and common pyrites, Fe 2 S 2 , with cobalt-blende, Co 2 SAs, and smaltine, Co 2 As 2 . 
 From this isomorphism a general analogy in composition between arsenic and sulphur 
 compounds, might possibly be inferred, were it not that such an inference would 
 speedily be found incompatible with the results of chemical analysis. But if arsenic 
 had been a rare and imperfectly known element, the isomorphism of marcasite and 
 mispickel might not improbably have led to the association of its compounds with 
 those of sulphur instead of with those of phosphorus. 
 
 Moreover, 2 atoms of one element are not unfrequently isomorphous with 1 atom 
 of another. We have already given several examples of this phenomenon when 
 referring to the isomorphism of sulphates with chromates, M 2 S0 4 and M 2 Cr 2 4 , of 
 perchlorates with permanganates, MC10 4 and MMn 2 4 , and of salts of silver with 
 salts of cuprosum, Ag 2 S and Cu 4 S ; and we have shown how the anomaly could be 
 readily explained away. Nevertheless it may be useful to point out definitely the 
 kind of difficulty to which this sort of isomorphism might possibly give rise. At the 
 present time, the ordinary salts of zinc, iron, lead, and silver, are alike thought to be 
 protosalts. Now we find that copper forms two chlorides, two oxides, two sulphides, 
 &c., in one set of which, the proportion of copper is twice as great as in the other. 
 Which of these sets then comprises the protosalts ? Judging from the isomorphous 
 relations of cupric compounds with salts of iron and zinc, we should say that the 
 cupric compounds were protocompounds, and that the atomic weight of copper was 
 31*7. Judging, on the other hand, from the isomorphous relations of cuprous com- 
 pounds with salts of lead and silver, we should say that the cuprous compounds were 
 the protocompounds, and that the atomic weight of copper was 63-4. 
 
 Lastly, we find that isomorphism sometimes subsists between compounds of a some- 
 what similar, but not of a strictly analogous chemical constitution. Thus, haematite, 
 (Fe 2 )'" 2 3 , is isomorphous with ilmenite, Fe'-Ti""0' J ; and zircon, Z""Si0 4 , with wer- 
 nerite, (Al 2 )"'Ca 1 Si0 4 . Again, nitrate of sodium, NaNO 3 , calc-spar, Ca 2 CO 3 , and red- 
 silver, Ag 3 SbS 3 , are isomorphous with one another; as are also nitrate of potassium, 
 KNO 3 , arragonite, Ca 2 C0 3 , and bournonite, Pb 2 CcuSbS 3 . Perchlorate of potassium, 
 KC10 4 , is isomorphous with sulphate of barium, Ba 2 S0 4 ; and sulphate of iron, 
 Fe 2 S0 4 .7II 2 0, is paramorphous, if not isomorphous, with arsenate of sodium, 
 Na 2 IIAs0 4 .7H-O. These illustrations are sufficient to show that the inferences de- 
 ducible from isomorphism, unless supported by chemical or by some other physical 
 evidence, nrast not be inconsiderately adopted as certain means for the determination 
 of atomic weights and chemical formulae. W. O. 
 
 ATRAIWSEWTUIWC STONE. Atramcntcnstein. A product of the partial 
 oxidation of iron pyrites, consisting of a mixture of ferrous and ferric sulphates with 
 free ferric oxide and a variable quantity of cupric sulphate and undecomposed pyrites. 
 ]t is used in the manufacture of ink (airamentuni). 
 
 X. Many plants belonging to this genus are used for the extraction 
 
 of soda. (Rochleder.) 
 
474 ATROPINE. 
 
 ATRIPLEX VERRUCIFERA, a chenopodiaceous plant growing in ti.e Kwgis 
 steppes, leaves 12*5 per cent, of ash containing 43'3 percent, of soluble salts, viz. 7 '2 per 
 cent, sulphate of potassium, 4'8 sulphate of sodium, and 8 carbonate of sodium, 24'6 
 chloride of sodium, and 1/9 caustic soda. (Gob el.) 
 
 ATROPIC ACID. An organic acid stated by Eichter (J. pr. Chem. xi. 33) 
 to exist in belladonna, and to be obtained by treating the aqueous extract with alcoholic 
 ammonia, evaporating the solution with potash, and decomposing the resulting 
 potassium-salt with sulphuric acid. It is said to resemble benzoic acid in form and 
 volatility ; but its properties, and indeed its separate existence, have not been well 
 made out. 
 
 ATROPIN-E, or D^TURINE. C 17 H 23 NO, or C^H^NC?. This alkali, dis- 
 covered in 1833, almost at the same time by Geiger and Hess (Ann. CLPharm. vii. 269), 
 and by Mein (ibid. vi. 67), exists in all parts of the deadly nightshade (Atropa Bella- 
 donna) ; it is also contained in the seeds of the thorn-apple (Datura stramonium}. 
 The alkaloid has been analysed by Liebig (Ann. Ch. Pharm. vi. 66), and by Planta 
 (ibid. Ixxxiv. 245) ; the latter has also analysed many of its salts. 
 
 To extract it, the roots of the belladonna are treated with strong alcohol, and the 
 extract left some hours in contact with caustic lime, then filtered, and supersaturated 
 with sulphuric acid, the alcohol having been previously driven off by a gentle heat. 
 A concentrated solution of carbonate of potassium is then added, and the liquid filtered 
 as soon as it begins to show turbidity. The crystals of atropine, which separate after 
 a while, are purified by repeated crystallisation from alcohol. Care must be taken not 
 to apply too strong a heat, as the atropine is easily decomposed. Eabourdin extracts 
 the atropine by chloroform. Fresh belladonna taken at the period of flowering, is 
 heated to 80 or 90 C. to coagulate the albumin. The clarified juice, when cold, is 
 mixed with caustic potash and chloroform, in the proportion of 4 grms. potash and 
 30 grms. chloroform to a litre ; and the whole is agitated for a minute and then left 
 to settle. After half an hour, the chloroform charged with atropine separates in the 
 form of a greenish oil, which after being washed, is distilled till all the cliloroform 
 passes over. The residue in the retort is extracted with a little water acidulated with 
 sulphuric acid, which dissolves the atropine, leaving a green resinous matter behind. 
 The acid solution is then treated with carbonate of potassium, and the precipitated 
 atropine crystallised from alcohol. 
 
 Atropine crystallises in colourless silky needles united in tufts ; by slow evapora- 
 tion of its alcoholic solution, it is often obtained in the form of a translucent vitreous 
 mass. It is but slightly soluble in water, but dissolves readily in alcohol, less in ether. 
 It is strongly alkaline, and has a very bitter taste. It melts at 90, and volatilises at 
 140C., undergoing partial decomposition. It is highly poisonous, causing vertigo, 
 headache, and even death ; it also produces persistent dilatation of the pupil. 
 
 Chlorine acts but slowly on atropine, producing a yellowish liquid, which contains a 
 considerable quantity of hydrochlorate of atropine. Tincture of iodine colours it brown. 
 Hot nitric acid attacks it, with evolution of red fumes. Chloric acid dissolves it, but 
 deposits it again unaltered, by spontaneous evaporation. 
 
 Atropine dissolves readily in acids, but the salts are difficult to crystallise. They 
 are bitter, acrid, and poisonous ; inodorous in the pure state. They are permanent in 
 the air at ordinary temperatures, but become coloured even at the temperature of boil- 
 ing water ; most of them are soluble in water and alcohol, and insoluble in pure ether. 
 Potash, ammonia, and their carbonates, precipitate atropine only from highly concen- 
 trated solutions of its salts ; the precipitate dissolves readily in excess of the alkali. 
 Tannin precipitates it only after addition of hydrochloric acid. 
 
 Acetate of atropine forms nacreous prisms grouped in stars : it is permanent and 
 very soluble; after being several times dissolved, it loses a little of its acid. (Geiger.) 
 
 The chloro-auratc, C 17 H 23 N0 3 .HCl.AuCl 3 , is precipitated as a yellow powder, gradually 
 becoming crystalline, when a strong solution of hydrochlorate of atropine is poured 
 into a dilute solution of trichloride of gold ; the liquid should be well shaken during 
 the mixing, to prevent the agglutination of the precipitate. The chloromercurate is 
 precipitated only from very concentrated solutions. The chloroplatinate is a pulve- 
 rulent precipitate, which rapidly agglutinates : it is very soluble in hydrochloric acid. 
 The hi/drochlorate crystallises in tufts (Geiger); according to Planta, it is uncrys- 
 tallisable. The nitrate forms a syrupy deliquescent mass. The picrate is a yellow 
 pulverulent precipitate. The sulphate crystallises, according to Geiger, in delicate, 
 colourless, nacreous needles, grouped in stars or tufts : it is very soluble. Planta did 
 not succeed in crystallising it. The tartrate is a syrupy mass, which becomes moist 
 in contact with the air. 
 
 The valcrate, prepared by dissolving atropine in an equivalent quantity of valerianic 
 
AUGITE. 475 
 
 acid diluted with 2 pts. of ether, and cooled to C., then adding a further quantity 
 of rectified ether (of 60 Cartier), equal to five times the weight of the atropine used, 
 and leaving the solution to itself in a glass cylinder at 10 C., forms colourless trans- 
 parent rhombic crystals, which refract light strongly. According to Callmann (J. pr. 
 Chim. Ixxvi. 69), they contain C^H'^NO 6 + H'-O.C 5 H 10 2 . They melt at 42 C., give 
 off the greater part of their water at 100, and at 120 begin to evolve vapours of 
 valerianic acid. The salt prepared as above is perfectly soluble in water. 
 
 AUGITE. Pyroxene. (Grm. iii. 402 ; Handw. d. Chem. ii. 556.) The name 
 of a class of minerals distinguished : 1. By a certain form, belonging to the mono- 
 clinic or oblique prismatic system, being a prism of 87 with the base inclined at an 
 angle of 74; and 2. By the general formula SiM 2 8 = M 2 O.Si0 2 , or S-ftfO^SiO 8 ,* 
 
 where M consists for the most part of Mg and Ca, giving the formula -.^.O.SiO 2 , less 
 
 frequently of Fe or Mn. Occasionally also IMg is replaced by 3H (polymeric iso- 
 morphism) ; and in the varieties called aluminous augites, 1 at. SiO 2 by 1 at. Al'O 3 (or 
 2@i0 3 by 3^ s ). 
 
 Specific gravity 3*23 to 3*5. Hardness = 3 to 6. Lustre vitreous, inclining to 
 resinous : in some varieties, pearly. Colour green, of various shades, verging on one 
 side to white or greyish- white, and on the other to brown or black. Streak white to 
 grey. Transparent to opaque. Fracture conchoi'dal to uneven. Brittle. 
 
 The nature of the metals, whether calcium, magnesium, or iron, which enter into the 
 composition of the mineral, produces considerable variations, not only of colour, lustre, 
 transparency, and density, but also of crystallographical development, sometimes giving 
 rise to differences in the magnitude of the angles in the primitive forms. These dif- 
 ferences of character constitute the distinctions between the several species of augite, 
 the principal of which are the following. 
 
 Common Augite, (M = Ca, Mg, Fe), the silica being sometimes also replaced by 
 alumina. Black, greenish, or brownish-black crystalline masses, with cleavage parallel 
 to the faces of a monoclinic prism of 87 and 93. Specific gravity 3*33 to 3'36. The 
 best developed crystals are found in basalt and other volcanic rocks. It occurs in the 
 lavas of Etna and Vesuvius, in the volcanic Eifel, in the Bohemian Mittelgebirge, in 
 the Fassathal, Iceland, and in numerous other localities. In some of these augites, the 
 Mg is almost wholly replaced by iron and calcium. Hudsonite from North America, 
 contains chiefly iron and scarcely any magnesium, a considerable portion of the silica 
 in this mineral is also replaced by alumina (SiO 2 by A1 4 3 ). 
 
 Pyroxene. This name is sometimes used as synonymous with augite, to denote 
 the entire family ; but it is especially applied by some mineralogists to certain varieties 
 of augite, having a green or dark green colour, viz. Fassaite, Coccolite (consisting of an 
 aggregation of roundish crystalline grains), Funkite, Baikalitc, &c. They are dis- 
 tinguished from common augite chiefly by containing a smaller amount of iron. 
 
 Diopside (white augite, Mussite). Essentially a silicate of calcium and mag- 
 nesium, (CaMg)SiO 3 , some varieties, however, containing small quantities of iron, man^ 
 ganese, and even hydrogen (H 3 instead of Mg). Colour, white, greyish, or greenish' 
 white, and light green. Occurs in very fine crystals, especially on the Mussa Alp in 
 Piedmont. 
 
 Malacolite. An augite rich in magnesium, also containing hydrogen, calcium 
 and iron being only subordinate. The water which it contains renders it softer than 
 the anhydrous augites. Salitc and Pyrgom are related in chemical composition to 
 malacolite on the one hand, and to pyroxene and diopside on the other. 
 
 Diallage and Broncite are, like malacolite, hydrated augites rich in magnesia, 
 but having also the silica more or less replaced by alumina. In hi/persthcne, the iron 
 predominates very strongly as protoxide. All these minerals, * to which also the 
 aitf/ltic talcs are related (see TAXC), possess a laminated structure, arising from the 
 peculiar facility with which they cleave in a particular plane. 
 
 Asbesto'idal augites, are hydrated calcio-magnesian augites of fibrous structure : 
 some of them occur as paramorphoses. This is the case with Traversdlite, a hydrated 
 ferroso-magnesian augite from Traversella in Piedmont. To this sub-species appears 
 also to belong a nearly pure ferrous augite, analysed by Grann. (Compt. rend 
 xxiv, 794.) 
 
 The following minerals also belong to the augite family : Mgyrin, probably a calcio- 
 sodium augite; Acmite or Achmite (p. 36), in which silica is replaced by alumina; 
 Spodumcne in which 3M 2 are replaced by A1 4 3 ; Jeffersonite, an augite containing 
 zinc; Rhodonite, a nearly pure manganese augite. 
 
 21 + 3 X 8. SiO^ = 28 + 2 X IG. 
 
476 
 
 AUGITE AVENTURIN. 
 
 The following are analyses of certain varieties of augite : 
 
 Wackenroder. Bonsdorff. 
 
 H. Rose. 
 
 HcrzelHis. 
 
 Lime .... 
 Magnesia . 
 Protoxide of manganese 
 Protoxide of iron. 
 Silica .... 
 Alumina 
 
 a 
 
 ft 
 
 c 
 
 d 
 
 e 
 
 f 
 
 24-74 
 
 24-76 
 
 23-57 
 
 24-94 
 
 23-47 
 
 20-00 
 
 18-22 
 
 18-55 
 
 16-49 
 
 18-00 
 
 11-49 
 
 4-50 
 
 0-18 
 
 0-32 
 
 0-42 
 
 2-00 
 
 0-61 
 
 3-00 
 
 2-50 
 
 0-99 
 
 4-44 
 
 1-08 
 
 10-02 
 
 18-85 
 
 64-16 
 
 54-83 
 
 54-86 
 
 54-64 
 
 54-08 
 
 50-00 
 
 0-20 
 
 0-28 
 
 0-21 
 
 
 
 
 100-00 99-73 99-99 100'66 99'67 96-35 
 
 a is diopside from Fassa ; b from Fammare ; c, salite from Sala ; d, malacolite from 
 Orrijerfor ; e from Dalecarlia ; /from Dagero. 
 
 Crystals having the form, structure, and composition of augite may be obtained by 
 exposing a mixture of 1 at. lime, 1 at. magnesia, and 2 at. silica (SiO 2 ) to the heat of 
 a porcelain furnace, and leaving it to cool very slowly (Berthier, Ann. Ch. Phys. [2] 
 xxiv. 376) ; similar crystals are likewise found among the slags of blast-furnaces. 
 (Noggerath, J. pr. Chem. xx. 501.) 
 
 The augites are not completely decomposed by any acid except hydrofluoric acid. 
 Their behaviour before the blowpipe varies according to their constitution. Diopside 
 yields a colourless nearly transparent glass ; ferruginous augite, a dark-coloured glass. 
 Augite dissolves readily in borax, but with difficulty in microscosmic salt, forming a 
 skeleton of silica. 
 
 AUGUSTITB. Syn. with APATITE. 
 
 AURAI>E. The name given by Plisson to a body which separates from oil of 
 neroli, on addition of alcohol, in white nacreous laminae ; it is probably the camphor or 
 stearoptene of the oil, and appears t6 agree in composition with the camphor of rose-oil. 
 It melts at 50 C., and on cooling solidifies to a waxy non-crystalline mass ; in a close 
 vessel it sublimes without decomposition. It is insoluble in water, dissolves in 10 pts. 
 of boiling alcohol of 44 Bm. ; soluble also in ether and in oil of turpentine. It ia 
 not attacked by acids. Fresh oil of neroli, which appears to be richer in this sub- 
 stance than the old oil, yields about 1 per cent, of it. (Handw. d. Chem. ii. 558.) 
 
 AI7HAJTTITT. Syn. of HESPEBEDIN. 
 
 AURXCHAXiCXTE. (Aurum, gold, and XO.\KOS, ore.) A. mineral occurring in trans- 
 parent, verdigris-green, needle-shaped crystals at Loktewsk on the Altai Mountains. 
 It appears to contain 2C0 3 Cu 2 .3ZnHO. When reduced, it yields a gold-coloured 
 alloy of copper and zinc. 
 
 AUROTEiliURITE. See TELLURIUM, GRAPHIC. 
 AITTOZKAXiITX:. See SPINEL. 
 
 AUTUWITE. Lime-urauite. (See UEANTTE.) 
 
 Atriiin*! xvxoSAXCUM or Mirsivinvi. The old name of disulphide of tin 
 prepared in the dry way. (See Tm.) 
 
 AVENXCT. A nitrogenous substance contained in oats, similar to, and most pro- 
 bably identical with, legumin. 
 
 A VENTURIS or AVACTTURXXT. A variety of quartz rock, which, when 
 polished, exhibits a strong reflected light from innumerable points of its surface, pro- 
 ceeding partly from minute crystals of mica Embedded in the mineral, partly from mi- 
 nute cracks and fissures. The most beautiful comes from Spain, but very fine specimens 
 have also been found at Glen Fernat in Scotland. The most usual colour is brown 
 or reddish-brown, enclosing golden-coloured spangles. The mineral is used as a gem, 
 but is often replaced by the artificial aventurin-glass, which even excels it in beauty. 
 
 AVENTURXN CHLASS, also called gold-flux. A brownish- coloured glass 
 interspersed with small spangles, which give it a peculiar shining appearance. This 
 glass was formerly used in the arts and for ornaments, and its preparation was long 
 kept secret by the manufacturers at Murano near Venice : it is now, however, prepared 
 in other localities. The following are analyses of this glass : a, by Schnedermann and 
 Wohler ; b, by P61igot ; c, by Kersten. 
 
 SiO 2 P 2 5 A1 4 3 Fe 4 3 Fe 2 Ca 2 Mg 2 K 2 Na 2 Cu Sn Pb 
 
 a . 65-2 1-5 6-5 8'0 4-5 2-1 3-2 3-0 trace 
 
 ft . 67-7 trace 3'5 8'9 5-5 7'1 3-9 2-3 M 
 
 c . 67'3 2-4 - 9-0 5-3 7'0 4-0 2-3 1-0 
 
AVENTURIN AZELAIC ACID. 477 
 
 Gahn first observeed that the spangled appearance of the glass is due to minute 
 shining, opaque, crystals, having the form of octahedral segments. Hence, and from 
 the composition of the glass, it was concluded that the crystals consist of metallic 
 copper. Clemandot and Fremy (Compt. rend. xii. 339), by melting together for 
 12 hours a mixture of 300 pts. of pounded glass, 40 pts. of copper filings, and 80 pts. 
 of iron filings, and cooling slowly, obtained a rather dull-looking glass containing 
 copper diffused through it in octahedral crystals. Pettenkofer, on the other hand, main- 
 tains that the spangles consist of crystals of a cuprous silicate, identical in composition, 
 but larger in size than the crystals of the compound which impart the deep-red colour 
 to hsematinone-glass or porporino (q. y.), and are diffused through a mass of glass 
 coloured green by protoxide of iron, the red crystals seen through the green glass 
 producing a mixed or resultant tint of brown. Aventurin-glass may in fact be pre- 
 pared with certainty by adding to 100 pts. of a not too refractory glass, 8 to 10 pts. 
 of a mixture of equal parts of ferrous and cuprous oxides, and leaving the mixture to 
 cool very slowly so as to facilitate the formation of crystals. A red crystalline cuprous 
 compound then separates, and the ferrous oxide remains in the glass, imparting a 
 green colour. Pettenkofer has also converted hsematinone into aventurin-glass by 
 addition of iron. (Handw. d. Chem. 2 te Aufl. ii. 504.) 
 
 A. VENTURIS? GIiAZE. A glazing for porcelain invented by Wo hi er (Ann. 
 Ch. Pharm. Ixx. 57). To prepare it, 31 pts. of kaolin from Halle, 43 quartz-sand, 14 
 gypsum, and 12 porcelain fragments, the whole finely ground and levigated, are stirred 
 up with 300 pts. of water, and to the paste thus formed are successively added the 
 solutions of 19 pts. of acid chromate of potassium, 47 acetate of lead, 100 protosul- 
 phate of iron, and sufficient ammonia to precipitate the whole of the iron. After the 
 potassium and ammonium-salts have been washed out by repeated decantation, tho 
 glazing is ready for use, and is laid on the burnt wares in the ordinary manner, and 
 burnt by the heat of the porcelain furnace. When cold, it forms a brownish ground, 
 containing crystalline laminae which have a golden lustre, but appear green and trans- 
 parent under the microscope and by transmitted light ; these crystals are regarded 
 by Wachter as chromic oxide or a compound of that oxide with ferric oxide. 
 
 AVIGNON*, GRAIN'S OP. (French Berries.) See YELLOW-BERRIES. 
 
 AXE-STONE. A sub-species of jade, from which it differs in not being of so 
 light a green, and in having a somewhat slaty texture. The natives of New Zealand 
 work it into hatchets. It is found in Corsica, Switzerland, Saxony, and on the banks 
 of the River Amazon, whence it has been called Amazonian stone. Its constituents are, 
 silica 50*5, magnesia 31, alumina 10, oxide of iron 5*5, water 2'75, oxide of chromium 
 0-05. U. 
 
 AXINITE. A silicate containing boric acid, so named from the axe-like bevelling 
 of its lateral edges. It is also called Thum-ite, from one of its localities, Thum in 
 Saxony. Its formula is 6M 2 0.2M 4 3 .8Si0 2 .B 2 3 , where M 2 stands for magnesia and 
 protoxide of iron, and M 4 3 for alumina, sesquioxide of iron, and sesquioxide of man- 
 ganese (Gm. iii. 453). Crystalline system, the triclinic or doubly oblique prismatic. 
 Specific gravity 3*294. Harder than felspar. Colour varying from a fine violet-brown 
 to leek-green, sometimes plum-colour ; some crystals are white and transparent, with 
 a glassy lustre. Before the blowpipe it exhibits the reaction of boron with acid sulphate 
 of potassium. In the unignited state, it is not attacked by hydrochloric acid, but 
 yields to it after fusion. It is found in various localities in France, Norway, Saxony, 
 the Harz, and the Alps ; at Botallack, near the Land's End, Cornwall ; and at Tre- 
 welland in that neighbourhood. 
 
 AZADIRINE. A bitter principle, perhaps an alkaloid extracted from Melia 
 Azadirachta, an East Indian tree, by Piddington (Geiger's Mag. xix. 50), who 
 states that it may be used as a substitute for quinine. According to O'Shaughnessy 
 (Pharm. Centr. 1844, p. 365), all the parts of Azadirachta Indica are very bitter. 
 The leaf is bitter and nauseating ; the bark is peculiarly bitter, and somewhat 
 astringent, and is used effectively in Bombay as a substitute for cinchona bark ; the 
 husk of the ripe fruit yields a very bitter fat oil, which possesses anthelmintic pro- 
 perties, and is used as an embrocation. 
 
 AZEI.AIC ACID. An acid stated by L aurent (Ann. Ch. Phys. [2] Ixvi. 154) 
 to be produced, together with suberic and other acids, in the oxidation of oleic acid 
 by nitric acid. It closely resembles suberic acid, being distinguished merely by a 
 lower melting point and greater solubility in ether. Laurent assigned to it the formula 
 C 19 H 36 5 ; but it is probably nothing but impure suberic acid. (Compare Ann. Ch. 
 Phiirm. xxxv 103.) 
 
 AZOBENZENE. Azobenzide, Azobenzol. C 12 H'N 2 . (Mitscherlich, Ann. Ch. 
 Phys. xxxii. 224); Zinin, J. pr. Chem. xxxvi. 96 ; Ivii. 173 ; Laurent and Gerhardt, 
 
478 AZOBENZENE AZOBENZOYL. 
 
 Compt. chim. 1849, 417.) A product of the reduction of nitrobenzene, or of the oxida- 
 tion of benzidine. It is obtained, together with phenylamine, by the dry distillation of 
 azoxybenzene ; or simply by distilling a mixture of nitrobenzene and alcoholic potash ; or 
 by distilling a mixture of 1 pt. nitrobenzene, 3 pts. iron, and 1 pt. acetic acid (Noble). 
 Azobenzene passes over towards the end of the operation, as a red oil, which solidifies 
 on cooling,; it is freed from aniline by hydrochloric acid, and recrystallised from alcohol 
 or ether. It forms large reddish-yellow scales, scarcely soluble in water, readily 
 in alcohol or ether. It melts at 65 C., boils* at 293, and distils undecomposed 
 (P. W. Hofmann). Vapour-density, by experiment, =94, referred to hydrogen; 
 6-50 referred to air; by calculation (2 vol.), 91 referred to hydrogen, 6-32 referred to 
 air (P. W. Hofmann, Ann. Ch. Phann. cxv. 364). It is soluble in nitric or sulphuric 
 acid, and is reprecipitated by water. Sulphide of ammonium and sulphurous acid con- 
 vert it into benzidine. It is not decomposed when heated to 250 C. over soda-lime. 
 
 When acted on by fuming nitric acid, it -yields two nitro-substitution compounds. 
 Nitrazobenzene^ C I2 H 9 (N0 2 )N 2 , is formed when the reaction is not prolonged : it sepa- 
 rates out in reddish-yellow crystals, which, after the acid has been decanted, are washed 
 with water, and dissolved in boiling alcohol (which generally leaves a residue of the di- 
 nitro compound). The solution deposits orange-yellow crystals of nitrazobenzene, which 
 are washed with alcohol and ether. When heated, it melts, and cools into a crystalline 
 mass. It is less soluble in alcohol than azobenzene. Dinitrazobcnzenc, C' 2 H 8 (N0 2 ) 2 N 2 , 
 is formed when the action of the nitric acid is prolonged for a few minutes : red 
 crystals are deposited, which are washed with nitric acid, water, and ether, and recrys- 
 tallised from boiling alcohol. It forms small reddish needles, which may be obtained 
 larger by crystallisation from fuming nitric acid. When heated, it melts to a blood-red 
 liquid, which crystallises on cooling. It is less soluble than nitrazobenzene in alcohol 
 or ether. Sulphide of ammonium converts it into diphenine (q. v.) F. T. C. 
 
 AZOBEirzxx.. C 21 H 1! >NO.(?) (Zinin, Ann. Ch. Pharm. xxxiv. 190; Laurent, 
 Bev. scient. xix. 445). Formed as a white granular precipitate, when a not too con- 
 centrated alcoholic solution of benzil is mixed with aqueous ammonia : after standing 
 in the liquid for ten hours, it is washed and recrystallised from alcohol. It forms 
 long, lustrous, iridescent needles, which are soluble in alcohol, alcoholic potash or 
 ammonia, and hydrochloric acid (whence it crystallises unaltered) ; insoluble in water, 
 potash, or ammonia. F. T. C. 
 
 AZOBCNZOIBE. C 42 H 33 N 5 (?) (Laurent, Ann. Ch. Phys. [2] Ixvi. -190). 
 A white amorphous powder, formed by the prolonged action of ammonia on crude 
 bitter-almond oil. It is insoluble in alcohol and ether. When heated, it melts, and 
 solidifies in crystalline granules ; more strongly heated, it is decomposed. 
 
 F. T. C. 
 
 AZOBEXrZOXBXXTX:. C 43 H 37 N 5 . (?) (Laurent, Ann. Ch. Phys. [3] i. 302.) A 
 product of the action of ammonia on crude bitter-almond oil. It forms small, shining, 
 oblique prisms : is inodorous, nearly insoluble in alcohol, slightly soluble in ether. It 
 is dissolved and decomposed by nitric, hydrochloric, or sulphuric acid. It solidifies 
 after fusion into a non-crystalline transparent mass. F. T. C. 
 
 AZOBEXTZOXX.XBE. C I4 H"N. (Laurent, Ann. Ch. Phys. [3] i. 304; xviii. 
 272.) A product of the action of ammonia on pure bitter-almond oil. The oil was 
 shaken up with potash and chloride of iron, distilled, and the first | which passed over 
 was covered with an equal volume of ammonia. Crystals were gradually deposited, 
 and in three weeks the oil was half solidified. The mass, when extracted with ether, 
 left a residue of azobenzoilide. 
 
 2(C 7 H 6 0) + NH 3 = C i4 HN + 2H 2 0. 
 
 It forms a microscopic crystalline powder, inodorous, insoluble in alcohol, very slightly 
 soluble in ether. It is decomposed by prolonged fusion. Hot nitric acid dissolves it, 
 apparently without decomposition ; hot sulphuric acid dissolves it, forming a yellow 
 solution, in which ammonia produces a white precipitate. F. T. C. 
 
 AZOBEXTZOITL. C 21 H I5 N 2 . (Laurent, Ann. Ch. Phys. [2] Ixvi. 185.) A 
 product of the action of ammonia on crude bitter-almond oil. When the yellow resinous 
 mass obtained by leaving the oil for four weeks in contact with an equal volume of ammo- 
 nia, is treated with boiling ether, a mixture of azobenzoylandbenzoylazotide is left un dis- 
 solved : the former is dissolved out by boiling alcohol, and purified by recrystallisation. 
 It forms a white, shining, crystalline, indorous powder, composed of irregular six-sided 
 tables ; insoluble in water, not very soluble in boiling alcohol. After fusion, it cools to a 
 transparent mass ; it is decomposed by a strong heat, leaving a residue of carbon. 
 
 * The boiling point of azobenzene is commonly stated, on Mitscherlich's authority, to be 193 C. 
 doubtless from a misprint in the original memoir. 
 
AZOBENZOYL AZOXYBENZENE. 479 
 
 According to Laurent (Ann. Ch. Phys. [3] i. 300), a mixture of equal volumes 
 crude bitter-almond oil, ammonia, and sulphide of ammonium, solidifies after a long 
 time ; and on treating the product with boiling ether, a white crystalline powder 
 remains behind, consisting of microscopic rhombic tables, which are nearly insoluble in 
 alcohol, and slightly soluble in boiling ether. Laurent calls this body hydrosulphate 
 of azobenzoyl, and assigns to it the formula C 21 H 18 N 2 S 1 -i, U p n which no reliance can be 
 placed. F. T. C. 
 
 AZOZ533IZCir:ii, HYDRIDE OP. Syn. with HYDROBENZAMIDE (q.V.) 
 
 AZOCimfAMYI., HYDRIDE OP. See CINNAMYL. 
 
 AZOCODEINTE. An organic base which Anderson obtained by the action of 
 sulphide of ammonium on nitrocodeine. (See CODEINE.) 
 
 AZODIPUlffE. Gmelin's name for AZOBENZIDE. 
 
 AZOERYTHRICT. See OBCEIN. 
 
 AZO1.EZC ACID. Syn. with (ENANTHYIJC ACID. 
 
 AZOXiITKOPEIiIiIC ACID. See LlTHOFEULIC AciD. 
 
 AZOI.ITHIZN-. See LITMUS. 
 
 AZOMARIC ACID. See PIMARIC ACID. 
 
 AZOPHECTYXiAXKINE of Zinin. A product of the decomposition of nitro- 
 phenylamine by sulphide of ammonium. (See PHENYLAMINE.) 
 
 AZOPHENTYXiAlttlSIE of Gottlieb, more correctly Nitrazophenylamine. A. 
 product of the decomposition of dinitrophenylamine by sulphide of ammonium. (See 
 PHENYLAMINE.) 
 
 AZORITE. A mineral occurring in the trachytic rock of the Azore Islands, in 
 small greenish or yellowish white pyramids. According to Hayes, it consists for the 
 most part of tantalate of calcium. 
 
 AZQSTTIiPHIDE OP BSltf ZEOTE. Syn. with HYDRIDE OF SULPHAZO-BENZOYI. 
 or THIOBENZALDIN. (See BENZOYL-HYDUIDE, decompositions by sulphide of ammonium.) 
 
 AZOTE, (o privative and fw); life.) Lavoisier's name for nitrogen. 
 
 AZOTAZJ. A name, not much used, for chloride of nitrogen. 
 
 AZOTIDES Syn. of NITRIDES. 
 
 AZOXYBSCTZEZtJE. Azoxybcnzidc, Azoxybenzol. C 12 H 10 N 2 0. (Zinin, J. pr. 
 Chem. xxxvi. 96; Ivii. 173; further, Ann. Ch. Pharm. cxiv. 217; Laurent and 
 Gerhardt, Compt. chim. 1849, 417.) When to a solution of 1 pt. nitrobenzene in 
 10 vols. absolute alcohol, 1 pt. powdered potash is added, the whole becomes brown, and 
 is heated to boiling. The mixture is shaken up and kept boiling for some minutes : on 
 cooling it sometimes deposits brown crystals. The mother-liquor is decanted, and 
 distilled till it forms two layers. The upper is a brown oily liquid, which, after de- 
 can tation and washing with water, solidifies into a mass of brown needles ; the lower 
 contains aqueous potash, carbonate of potassium, and a brown potassic salt, almost in- 
 soluble in alcohol. The crystals are dried with filter-paper, and recrystallised from 
 alcohol or ether : they are easily decolorised by passing chlorine through their alcoholic 
 solution. 2 pts. nitrobenzene yield 1^ pt. azoxybenzene. 
 
 Thus obtained, azoxybenzene forms yellow, shining, four-sided needles, often an inch 
 long, as hard as sugar, without smell or taste, insoluble in water, hydrochloric, or dilute 
 sulphuric acid, potash, or ammonia, readily soluble in alcohol, still more so in ether. It 
 melts at 36 C., and solidifies on cooling to a crystalline mass : it is decomposed by dry- 
 distillation, yielding aniline and azobenzene, and leaving a residue of carbon. It is 
 not attacked by chlorine : bromine attacks it, forming a yellow componnd, very slightly 
 soluble in alcohol. Strong sulphuric acid dissolves it, forming apparently a copulated 
 acid. Sulphide of ammonium and sulphurous acid convert it into azobenzene. 
 
 Nitrazoxy benzene, C 18 H 9 (N0 2 )N 2 O. Azoxybenzene is not attacked by dilute 
 nitric acid, but when gently heated with nitric acid of specific gravity 1'45, it dissolves, 
 with great evolution of heat, and the liquid, if carefully cooled, solidifies after a while, to 
 a thick pulp, consisting of two isomeric nitro-compounds, nitrazoxybenzene, and 
 isonitrazoxybenzene, which may be separated by their different solubility in 
 alcohol. If the pulp just mentioned be thrown on a filter, washed with water, treated 
 three or four times with a quantity of boiling alcohol not sufficient to dissolve the 
 whole (not more than 4 pts. alcohol to 1 pt. azoxybenzene), and the decanted liquors 
 left to cool, crystals of nitrazoxybenzene are first deposited ; and after a while, shining 
 needles make their appearance in the midst of them. If the liquid be then filtered, 
 and part of the alcohol distilled off, isonitrazozybenzene separates on cooling, in the 
 form of an oil, which quickly solidifies in a crystalline mass ; it may be purified by 
 two or three crystallisations from small quantities of very strong alcohol. 
 
480 AZOXYBENZENE BABINGTONITE. 
 
 Nitrazoxybcnzenc is a yellowish crystalline body, slightly soluble in boiling alcohol 
 or ether. It is promptly attacked by boiling alcoholic potash, and coloured brown ; 
 on adding water, a yellowish-rod powder is precipitated, which may be crystallised 
 from boiling oil of turpentine. This compound appears to contain C 12 H 9 N 3 (Lau- 
 rent and Gerhardt). If the action of alcoholic potash be prolonged, the mixture 
 becomes blue ; the colour is destroyed by water. An alcoholic solution of sulphydrato 
 of ammonium converts nitrazoxybenzene, with separation of 3 at. sulphur into a crys- 
 tallisable base, which dissolves readily in alcohol and in benzene, and forms salts with 
 acids. 
 
 Isonitrazoxybenzcne forms crystals very much like those of nitrazoxybenzene, but 
 easily soluble in alcohol. It dissolves also in a large quantity of ether, and in benzene, 
 and often crystallises from these liquids in fine rhomboidal prisms. It melts at 49 C. 
 but does not volatilise without decomposition. When 1 pt. of this substance is treated 
 with a solution of 1 pt. of potash in 8 pts. of alcohol, it melts and dissolves with 
 ebullition, giving off the odour which is evolved on treating nitrobenzene with alcoholic 
 potash. On boSing the liquid, a resinous mass separates, which yields by distillation 
 an orange-coloured product, which crystallises from alcohol, and resembles nitro- 
 phenylamine. At the same time, an oily body is formed not possessing basic properties, 
 and charcoal remains behind. 
 
 Isonitrazoxybenzene treated with alcoholic sulphydrate of ammonium, yields a body 
 having the composition C 12 H 9 N 3 : 
 
 C 12 H 9 (N0 2 )N 2 + 2H 2 S = C I2 H 9 N 3 + 2H 2 + S 2 . 
 
 This body is insoluble in water, very soluble in alcohol, ether, benzene, and rock-oil, 
 soluble also in acids ; but does not form definite salts. It melts at 85 C. to a yellow 
 liquid, which solidifies on cooling, provided the temperature has not been raised too 
 high. If a strong heat be applied, a brown liquid distils over, soluble in alcohol, 
 though less so than the original substance. F. T. C. 
 
 UKTE. Ghnelin's name for AZOXYBENZENE. 
 
 ACID. A brown substance produced by the spontaneous decompo- 
 sition of cyanogen and hydrocyanic acid. An aqueous or a dilute alcoholic solution of 
 cyanogen or aqxieous hydrocyanic acid, when left to itself for some time, especially after 
 addition of ammonia or potash, acquires a brown colour and gradually deposits brown 
 flakes, consisting of azulmic acid. The solution contains azulmate of potassium or 
 ammonium, from which the acid may be precipitated by the stronger acids. The 
 same product is obtained by passing cyanogen gas into aqueous ammonia or alcoholic 
 potash. Respecting the composition of this substance, statements vary greatly; ac- 
 cording to Pelouzeand Eichardson (Ann. Ch. Pharm. xxvi. 63), it is C 4 H 4 N 4 2 , 
 that is to say, 4 at. cyanogen + 2H 2 : but it is doubtful whether any of the analyses 
 have been made upon a pure definite compound. The acid yields by dry distillation 
 hydrocyanic acid, ammonia, and water, and leaves a residue of charcoal containing 
 nitrogen. (For a full account of all the modes of preparation, properties, and reactions 
 of azulmic acid, see Grmelin's Handbook, xi. 375.) 
 AZURE-BX.UE. See SMALT. 
 
 AZURE-STONE ) 
 
 AZURITE I SeeLAZULiTE. 
 
 B 
 
 BABIKTGTONTTE. A mineral consisting principally of silicate of iron and cal- 
 cium, found near Arendal in Norway, in the Shetland Isles, at Gouverneur in St. Law- 
 rence County, New York, and at Athol in Massachusetts. It forms short, nearly right 
 angled rhomboidal prisms, of the triclinic system, with truncated edges and obtusely 
 bevelled summits. Fracture imperfectly conchoi'dal. Colour dark greenish-black, 
 with vitreous lustre. Opaque in the mass, translucent in thin splinters. Hardness 
 5-5 to 6'0. Specific gravity 3 '4 to 3 '5. Brittle, producing a greenish-grey streak. 
 Melts easily with intumescence before the blowpipe, forming a brownish-black shining 
 globule, attracted by the magnet. It is slowly decomposed by boiling hydrochloric 
 acid. The mineral has been analysed by Arppe (Berz. Jahresb. xxii. 20), and 
 by K. D. Thomson (Phil. Mag. [3] xxvii. 123), but its formula has not yet been 
 determined : 
 
 SiO 2 Mg 2 Ca 2 Fe 2 Mn 2 A1 4 3 . 
 
 54-4 2-2 19-6 21'3 1-8 0'3 0'9 = 100-5 (Arppe) 
 
 47'5 2-2 147 16'8 10-2 6'5 1-2 = 99-1 (Thomson) 
 
 BABXiAH or NEB-WEB. The commercial names foe the fruits of several 
 
BABL AH BALANCE. 
 
 481 
 
 species of acacia. The principal varieties are East Indian bablah, from the Acacia 
 Bambolah (Roxburgh], and Senegal and Egyptian bablah, from Acacia nilotica 
 (Delile). The pericarp of these fruits contains a dark brown astringent juice. The 
 aqueous extract contains, according to Chevreul (Lecons de Chimie appliquee a la 
 Teinture, ii. 211), gallic and tannic acids, a red colouring matter, and a nitrogenous 
 substance, besides other substances not yet examined. East Indian bablah yields to 
 boiling water 49 per cent, of soluble matter; Senegal bablah 57 per cent. ; neverthe- 
 less, according to Ghiibourt, the East Indian variety is richer in tannic and gallic acid, 
 and therefore more valuable. Bablah is used in calico-printing in combination with 
 alumina and iron mordants, to produce various shades of fawn-colour. The tint pro- 
 duced by the seeds is different from that obtained with the husks ; the seeds are said 
 to contain a red colouring matter, and to be used in Egypt and India for dyeing 
 morocco. (Handw. d. Chem. 2 te Aufl. ii. 603.) 
 
 BABUIi-CrUM or GOND-BABUXi, an inferior sort of gum arabic, from the 
 babul tree, Acacia Arabica (Willd.) growing in Bengal. 
 
 BABYLONIAN* QUARTZ. This name is given to peculiar groups of quartz- 
 crystals, composed of thin crystalline plates, disposed one above the other Hke terraces. 
 It is found at Beerlston in Devonshire. 
 
 BAGRATXOXXXTX:. See OBTHITE. 
 
 BAXERXST or BAXERXTE. A variety of niobite found at Bodenmais in 
 Bavaria and at Limoges in France. 
 
 BAXXAXiXTE. A green modification of diopside. 
 
 BAXiAXJCE. Chemistry being concerned with the relative masses or quantities 
 of the elements which compose all known substances, and the weight or force of 
 gravitation of a body being the only practicable measure of its mass or quantity 
 of matter, the balance, which shows the equality of two weights, and may hence 
 determine the ratio of all commensurable weights, is the chemist's most important 
 instrument. 
 
 Fig. 78. 
 
 Theoretically speaking, the balance consists of a lever or inflexible straight line 
 turning with perfect freedom on its central point. A weight is applied to each extreme 
 point, and the force of gravity acting perpendicularly downwards, if either of these 
 weights be in the least degree greater than the other, it will prevail and cause the lever 
 to revolve in its own direction. The equilibrium of the lever or balance affords the 
 desired criterion of perfect equality of weight ; and an arbitrary weight being assumed 
 as a standard, we can arrive, theoretically speaking, at any of its multiples or sub- 
 multiples by successive duplication and bisection combined with addition and sub- 
 traction, and a perfect measure of all weights from the greatest to the least may thus 
 be attained. The results of course are not absolute weights, as we say in common 
 speech, but ratios of weights to each other, or to the standard unit-weight. 
 
 Practically, however, the balance consists of a metal beam with two almost equal 
 VOL. I. II 
 
482 
 
 BALANCE. 
 
 Fig. 79. 
 
 and similar arms, suspended near its centre of gravity on a pivot, the weights to be 
 compared being also suspended from two pivots at nearly equal distances from the 
 centre pivot. In the balance thus constructed, we have by no means the simple and 
 perfect comparison of two weights supposed in theory ; the weight of the beam, the 
 friction of the pivots, their unequal distances from the middle one, the resistance of 
 the airland possibly other causes, introduce small extraneous forces, which render the 
 comparison required more or less uncertain and erroneous. 
 
 THE CHEMICAL BALANCE, is adapted for the ordinary operations of quantitative 
 analysis, and is usually capable of weighing any quantity less than 100 grammes or 
 1500 grains^ In its most perfect form (see fig. 78) it consists of a perforated brass 
 beam, cast in a single piece, combining great strength and perfect inflexibility with 
 comparatively small weight. It is suspended at the centre on a knife-edge of agate 
 about an inch long, and turns on a single polished plane of agate fixed on a projecting 
 brass support, which enters a perforation of the beam, and does not impede its mo- 
 tion. The agate knife-edge is firmly embedded in a wedge-shaped piece of brass, and 
 being once adjusted exactly at right-angles to the plane of the beam, is then permanently 
 fixed. At each end of the beam is a smaller agate prism (see Jig. 79), with the edge 
 
 uppermost, fixed in a brass setting, which 
 is capable of a little lateral movement, but 
 slides upon a brass plane, in such a man- 
 ner that the two extreme edges and the 
 centre edge are all appreciably in one 
 plane, as may be seen by looking along 
 them. The extreme edges may be moved 
 to or from the centre edge by little ad- 
 justing screws, and fixed in the desired 
 position with the assistance of two clamp- 
 ing screws. 
 
 Upon these extreme edges (i. e. knife- 
 edges) are balanced two agate planes, from 
 which, by the bent wire and a series of hooks 
 and light wires, the pans are suspended. 
 Except, however, when a weighing is actually being made, the agate planes and 
 edges are never in contact, but the beam and pan suspensions are borne by a frame or 
 movement, having in the centre two Ys (fig. 78) which catch projecting pins close to 
 the centre edge, and lift the beam about of an inch off the plane, while steel points 
 (shown in dotted outline in^. 79.) entering hollows in the lower surface of the pan- 
 suspensions, likewise raise these planes off the edges, and retain them in the exact 
 positions proper for a new experiment. The movement of the brass frame is governed 
 by a rod descending through the pillar of the balance and resting on a simple eccentric, 
 by the turning of which it is gradually raised or lowered. In the best balances too, a 
 second eccentric, by means of two bent levers, raises supports beneath the pans of the 
 balance, and either holds these safely while weights are being placed in them, or 
 checks their oscillations preparatory to the release of the beam. The two eccentrics are 
 so adjusted that on turning the handle, the pan supports are first rapidly dropped ; 
 the beam is then very gently lowered on to the centre plane ; and lastly the pan- 
 suspensions are in the most delicate manner left free upon the extreme edges, the 
 beam being perfectly horizontal and undisturbed, so as not to show the slightest prepon- 
 derance one way or another. Much of the excellence of a balance, as it is employed 
 in chemistry, depends upon these several movements being smoothly performed, and 
 the parts being released without the least stickiness ; otherwise the beam is thrown 
 into oscillation, and the true approach to equilibrium cannot be readily observed. 
 
 Most of the weight of the beam and frame is usually borne by a spiral spring in the 
 interior of the column. An index moving over an ivory scale one inch long, divided 
 into twenty parts, indicates the movement of the beam. The index should, of course, 
 point exactly to the centre division, both before the beam is raised and when it is free 
 and unloaded. The balance is enclosed in a glass case, with convenient windows, not 
 shown in the figure ; but when a very bulky object has to be weighed, the finger- 
 screws at the base of the column (fig. 78) are to be loosened : the column and beam 
 may then be turned through about 60, so that the scales extend without the case. 
 Two spirit-levels, or a circular level, and levelling screws, are attached by which the 
 whole instrument must be adjusted to horizontally. Above the centre of the beam 
 is a small weight, which we may call the gravity-bob, and which, being screwed up 
 or down, regulates the stability of the balance, while a small vane being turned to the 
 right or the left adjusts the beam to equilibrium. In the figure too will be seen an 
 arrangement of rods, by which a small rider weight may be placed upon any part of 
 the beam, the balance case remaining closed. 
 
BALANCE. 
 
 483 
 
 The balance above described is by Oertling, of Bishopsgate Street, London, who like- 
 wise constructs the chemical balance in seven different varieties more or less elaborate. 
 
 Fig. 80. 
 
 Fig. 81. 
 
 Fig. 82. 
 
 The largest of these, with a 16-inch beam, able to bear two pounds in each pan, and 
 yet turn with y^ grain is a remarkably fine instrument. The German balances made 
 by Oertling of Berlin, Standinger of Giessen, Steinheil of Munich, and others, are 
 extremely delicate and well made instruments. Deleuil of Paris enjoys also a just 
 celebrity for his chemical balances. M. Stas, in his late researches upon the atomic 
 weights, employed a balance , 
 
 by Gambey, which turned to *& 83 ' * 84 ' 
 
 half a milligramme when laden 
 with a kilogramme ; also one 
 by Sacr6 of Brussels, carry- 
 ing two or three kilogrammes 
 and turning with - 3 milli- 
 gramme. Fig. 83 shows the 
 terminal suspension of a de- 
 licate balance by Fortin of 
 Paris, capable of indicating 
 one part in a million, while 
 fig. 84 is from a German ba- 
 lance. 
 
 THE ASSAY BALANCE is specially adapted for weighing small objects with great 
 accuracy and 'rapidly. The French assay balances consist of a very light steel beam 
 mounted in the manner of a pair of scales with hook pan suspensions, yet their perfor- 
 mance is good. 
 
 Oertling constructs the assay balance in five forms, of which the most commonly 
 employed has an 8-inch plain brass beam with a centre steel knife-edge and hook pail 
 suspensions, adjustable by a small screw, as shown in fig. 80. It is not adapted to 
 bear more than two grammes in each pan, and will perhaps indicate the ^ part of a 
 milligramme. 
 
 Another kind has an 8-inch perforated beam, with three agate edges and planes, 
 and in fact all the elaborate movements and adjustments of the chemical balance 
 above described, on a small scale. It will bear 10 or 15 grammes in each pan, and yet. 
 indicate surely and rapidly about ^ of a milligramme. 
 
 Lastly, we may mention the 10-inch assay balance, with a very light perforated 
 beam. A figure and a short description of this balance will be found under the article 
 GOLD ASSAY, but the terminal suspensions are shown here in figs. 81 and 82, and are 
 formed of two small screws, bearing sharp points of ruby, one working into a little 
 hollow, the other into a little channel in a steel cross-piece, from which the pan is 
 suspended. 
 
 In contrast to the last balance it may be mentioned that Oertling constructs balances 
 on the principles of the chemical balance with a beam 4 feet long, able to bear 
 2000 ounces in each pan, and yet turn with half a grain, or the one-millionth part of the 
 load. They are chiefly employed in the several English and American mints for 
 weighing bullion, but might be useful in some scientific investigations. See Jury 
 Eeports on the Great Exhibition of 1851 (p. 258). 
 
 It is of little use to describe forms of the balance which are now antiquated. Those by 
 Eobinson, by Eamsden, and his successor, Berge, and by Barrow, had beams composed 
 of two hollow brass cones joined at the base with many elaborate adjustments. A 
 balance made by Eamsden for the Eoyal Society is said to have indicated one part in 
 seven millions. In the Gottingen Transactions, is described a balance constructed by 
 Gauss and Weber, the beam and scales of which were poised on watch springs, a 
 method contrived by Gauss. Beams suspended by ribbons, threads, or turning oa 
 little spheres of steel have been tried by Steinheil ; but in no instrument have attempts 
 to invent new forms been more futile. 
 
 ii 2 
 
484 BALANCE. 
 
 THE ADJUSTMENT OF THE BEAM to the due degree of sensibility and accuracy 
 has to be entirely performed by repeated trial-weighings, and requires the greatest 
 skill. 
 
 Firstly, if the three edges of suspension are not already in one plane, but admit of 
 adjustment, as is sometimes the case, proceed as follows: Without weights in 
 the pans poise the beam, and then raise or lower the lob until the vibrations are ren- 
 dered very slow ; now put weights into the pans equal to about half the greatest load 
 the balance is to carry, so that the beam may be poised again ; if it now vibrates 
 slowly as before, it proves the adjustment to be perfect ; but in case it either over- 
 sets or vibrates too quickly, restore it to slow motion by the adjusting weight or 
 gravity-bob, as we may call it, noting the number of turns of the screw and parts of a 
 turn which were required to produce slow motion ; now turn the screw the contrary way, 
 through double the noted quantity, and then produce the required slow motion by the 
 proper adjustment at the end of the beam. Repeat the operation till the adjustment 
 is perfect. 
 
 Secondly, to adjust the edges of suspension to equal distances ; poise the beam with 
 weights as in the last case, and then change the pans and suspensions from one side to 
 the other. If equilibrium still holds, the adjustment is perfect ; if not, take as much 
 hair or wire as when put into the apparently lighter scale, will restore the balance ; 
 take away half of it, and poise the beam by the proper adjustment at the left end, 
 which completes the process. Instead of placing any weights in the pans, all the 
 poising may be conveniently done by a rider-weight on the beam, and in the last 
 operation it is to be removed half way towards the centre of the beam. The adjust- 
 ment of the edges to perfect parallelism is of course indispensable ; we only presume 
 that it is done by placing narrow planes or hooks on different parts of the edges and 
 moving these until the apparent weight is the same on whatever part the weight 
 bears. 
 
 A good balance in perfect adjustment should bear most of the following tests : 
 Without weights, of course, it should remain with the index at zero, or make equal 
 slow excursions on either side. The pans being removed, the beam alone should be iu 
 equilibrium, and oscillate probably much more quickly. If there be nothing in the con- 
 struction of the balance to hinder it, the beam should be turned round from left to right 
 and should act as before ; this test is a severe one, generally disclosing as it does 
 some defect in the work of the middle knife-edge and the planes on which it rests. 
 If the pans and suspensions have been separately adjusted to equality, which is 
 advantageous, although not quite necessary, equilibrium should hold when the pans 
 and suspensions are variously changed in both positions of the beam. Lastly, the 
 pans being fully and equally loaded, the weights should be changed from pan to pan, 
 and equilibrium yet hold, proving the lengths of the arms to be fully equal. 
 
 A good balance, too, may be known by its giving the weight of an object, the same or 
 nearly so, when weighed several times successively. There are few balances that will 
 do this with certainty to the last minute fractions which they are capable of in- 
 dicating. 
 
 WEIGHTS. The results required by the chemist in analyses being merely comparative 
 or proportional, the choice of a unit weight is a matter of indifference, provided 
 that it be not varied during the progress of an experiment. But it is most con- 
 venient to adopt weights connected with some national standard, so that absolute 
 weighings may if necessary be recorded. Grain weights are still sometimes used by 
 English chemists, but most men of science of all nations appear by a kind of tacit 
 agreement to have adopted the French standard weight, the gramme, with its uniform 
 series of decimal multiples and submultiples ; and we therefore strongly recommend 
 its exclusive employment by every scientific chemist. 
 
 A complete set of weights extends from the smallest that the balance will indicate, 
 up to the greatest that it will bear, and the series usually supplied with a balance ia 
 as follows : 
 
 001 
 
 gramme 
 
 01 
 
 gramme 
 
 1 gramme 
 
 1-0 
 
 gramme 
 
 10-0 
 
 grammes 
 
 001 
 
 M 
 
 01 
 
 n 
 
 1 
 
 }J 
 
 1-0 
 
 
 
 10-0 
 
 > 
 
 001 
 
 B 
 
 02 
 
 tf 
 
 2 
 
 }> 
 
 1-0 
 
 
 
 20-0 
 
 N 
 
 002 
 
 M 
 
 05 
 
 D 
 
 5 
 
 n 
 
 2-0 
 
 
 50-0 
 
 If 
 
 C05 
 
 M 
 
 
 
 
 
 5-0 
 
 > 
 
 
 
 the whole making up just 101 grammes. These are arranged most conveniently in two 
 little wooden stands, which may either be introduced into the balance case or enclosed 
 together with the forceps in a separate box. A glass cover also lies over the small 
 weights. The weights from 1 gramme upwards are best made of brass gilt ; below 
 1 gramme, of platinum in the form of flat squares, with a corner bent up for holding 
 in the forceps, the weight being stamped on each piece. The milligramme weights 
 
BALANCE. 485 
 
 are sometimes made of palladium or aluminium ; but tlie latter metal is rather too soft 
 for the purpose, and is apt to wear away. 
 
 An admirable improvement in the modern balance consists in its partial employment 
 on the principle of the steel-yard, as far as regards the estimation of the last minute 
 fractions. A small rider, or hanging weight of thin gold (or brass) wire, is placed upon 
 the upper edge of the beam either by the forceps, or more conveniently without opening 
 the case, by a brass sliding rod and a little arm (see fig. 78), on either side of the beam. 
 Now the weight which this rider exerts towards turning the beam is such a fraction of 
 its whole weight in the pan, as its distance from the centre of the beam is of the distance 
 of the pan-suspension from the centre. The rider commonly weighs -01 gramme, and 
 each arm of the beam is graduated into twenty parts ; but the fifth part of these 
 divisions may easily be guessed, so that the fractional weight may really be read off to 
 the Y5o P ar t of the rider weight, or '0001 gramme. This simple contrivance, compared 
 with the use of minute weights in the pans, presents the following advantages. 
 
 1. Saving of much time and trouble. 2. Greater accuracy, small weights being 
 liable to collect dirt, or to be rubbed or injured. 3. Minute estimation of weights to 
 any required degree. 4. Diminished chance of error in reading off the weight. With 
 numerous small weights errors are certain frequently to occur. 
 
 The series of grain weights 1, 2, 3, 4, 10, 20, 30, 40, &c. is not uncommonly em- 
 ployed, and is quite as convenient as the series 1, 1, 2, 5, 10, &c. As a curious fact, it 
 may be mentioned, that the series of powers of 3, viz. 1, 3, 9, 27, 81, affords the greatest 
 number of combinations to a given number of weights. Thus twelve such weights give 
 by addition or subtraction, any integral number from 1 to 265,720, while 21 weights of 
 the series, 1, 1, 2, 5, do not reach 200,000. 
 
 Weights when used in a laboratory must almost always become too light by wear, or 
 more commonly too heavy by corrosion of the brass. Were the error always propor- 
 tional to the size of the weight, all error would be eliminated in any comparative 
 result. But this is not usually the case, since the mass increases as the cube, while 
 the surface increases as the square of the diameter. Hence the small weights will be 
 more erroneous in proportion than the large. Weights should never be rubbed, and if 
 dusty, should be wiped with a silk handkerchief or a camel' s-hair brush. Small platinum 
 weights may be cleaned if necessary, by momentary exposure to the flame of a spirit- 
 lamp. One set of weights should, if possible, be carefully preserved beyond the in- 
 fluence of fumes, and should not be touched but by ivory-pointed forceps. The weights 
 commonly used should occasionally be tested against these, to see whether their errors 
 be disproportionate ; or weights may less satisfactorily be tested against each other. 
 An experienced weigher will never trust even the best balance maker as to the ac- 
 curacy of his weights, but will always test them against each other in various ways, on 
 first receiving them. Many conclusions, observes Faraday, tending to subvert most 
 important chemical truths, might be quoted as having arisen solely from errors in 
 weights and balances. 
 
 In assaying (see GOLD ASSAY), a special unit and set of weights is adopted to suit 
 the weighings required ; the same might be advantageously done in any large set of 
 analyses or experiments. 
 
 Much time will on the whole be saved in weighing, if the weights be taken me- 
 thodically in their proper order, 10, 5, 2, 1, 1, except, of course, the slow motion of 
 the balance indicate that only a small weight more should be added. For if an unknown 
 weight exceed 10 but fall short of 20, it is an even chance that it be above or below 15, 
 so that if the weights 2, 1, 1, be used after the 10, it is as likely as not that the 
 weigher will lose his trouble, and have to resort to the weight 5. In this respect the 
 series of weights (avoirdupois) 16, 8, 4, 2, 1, %, i, &c. is obviously the most advantageous. 
 
 When equilibrium is nearly attained, the expert weigher will notice the rapidity 
 with which the index of the beam traverses the arc, or the extent of the oscillation if 
 it be less than the whole arc, and comparing this with the load in the pans, and with 
 his previous experience of the same balance, will closely estimate the alteration of 
 weight required, and thus save half the time and trouble which the adjustment would 
 otherwise have occupied. It will afterwards be shown that the oscillations of a good 
 balance may give sure determinations of the most minute fractional weights. 
 
 We cannot too strongly impress upon the reader the danger of mistakes in reading 
 off the weights in the pan of a balance. The danger is greater with small than with 
 large weights, and this alone would be sufficient reason for the use of a rider weight. In 
 any case, the weights in the pan should be read, then taken out and arranged in order, 
 and again read ; lastly restored to the pan, and fresh trial made. Or the reading of the 
 weights may be compared with the vacancies in the box of weights. When the vibra- 
 tions of the balance have to be read, the divisions of the scale should be numbered 
 from left to right continuously. For if the zero be in the centre, the signs + and 
 must be used, and mistakes are sure to occur. Under the article GOLD ASSAY will be 
 
 ii 3 
 
486 BALANCE. 
 
 found an instance in which vibrations are used with great convenience in estimating 
 the last fractions of weights. 
 
 The casual sources of mistake are too many to mention. Not unfrequently a rider 
 may remain unnoticed on some part of the beam, and vitiate several weighings. When 
 a bulky or flexible object is being weighed, some part is very likely to come in contact 
 with the balance case. We have even known a scrupulously exact gold-assayer led 
 into serious mistakes by a small fly, which settled on his balance, unobserved at the 
 time. 
 
 An object heated many degrees above the temperature of the air, cannot be accurately 
 weighed ; for it is surrounded by ascending currents of air, which cause its apparent 
 weight to vary every moment, and it is very likely to heat and expand unequally the 
 arms of the beam above. Special modes of weighing hygroscopic substances, liquids, 
 powders, gases, &c., must be adopted according to the nature of the case ; the chemist 
 must generally depend for these on Ms own ingenuity, but will find many valuable 
 directions in Faraday's Chemical Manipulation, section II., also in Grreville Williams's 
 Chemical Manipulation. 
 
 If we have to compare the weights of any two objects, A and B, which are held or 
 accompanied by other objects, X and Y, the weights of the latter may be perfectly 
 eliminated if each of A and B be weighed as often in X as in Y, and the mean result 
 taken. 
 
 We will make the following suggestions for the care of a balance. 
 
 1. It should never be moved, if possible, from its appointed place ; for this would 
 not only disturb its adjustment to horizontality, but the swinging and shaking of the 
 pans and beam would be likely to injure or slightly alter the condition of the balance. 
 The operator too will never weigh so well as in a place, and with a light to which 
 he is accustomed. 
 
 2. The balance should not be cleaned or altered often or hastily. A good cleaning, 
 once every three months, for instance, is enough, if the balance case be kept well 
 closed. An hour or sometimes two or three, may well be spent in the operation of 
 cleaning. All the loose parts should be carefully taken out and dusted ; the move- 
 ments cleaned and fresh oiled ; the suspensions polished with a piece of soft leather. 
 Then all the parts are to be put together again, and brought to elaborate adjustment, 
 which with careful usage will be maintained for some months. 
 
 3. The chemist should be perfectly acquainted with the capacity, the general 
 character, and also the particular condition, at any moment, of each of his balances. 
 
 4. Before every weighing, or set of weighings, he should try whether the unloaded 
 balance is in perfect equilibrium; if not, he may brush the pans or beam with a 
 camel's hair brush, to remove dust, or if he dust the preponderating side only, it will 
 often restore equilibrium. He should not touch the little regulating vane, or alter any 
 part of the balance, without being satisfied that some special cause for it has arisen. 
 The one great essential of accuracy is perfect uniformity in everything but the thing 
 to be measured, and no one can have faith in a measuring instrument which is always 
 changing. 
 
 5. It is almost needless to say that a balance, especially one with steel knife-edges, 
 must be kept beyond reach of all acid fumes or damp. A small vessel of quick lime 
 or chloride of calcium should be in the balance case, and this should be kept constantly 
 closed. 
 
 All weighing out of reagents, where a grain more or less is not material, should 
 be made with common apothecaries' scales on the laboratory table. 
 
 A balance should be placed in a good light, falling if possible over the right shoulder 
 of the operator. But it may also with advantage be placed before a window, provided 
 that a purple silk shade be used. The purple Light thus thrown behind the balance is 
 subdued, agreeable, and complementary to the yellow of the brass. As a general rule, 
 the object to be weighed should always be placed in the left hand pan, which we may 
 hence call the object-pan. The other, or weight-pan, will thus be conveniently opposite 
 the right hand. In assaying, this arrangement is reversed. 
 
 The number of balances required in a chemical laboratory may vary from one to 
 twenty, or more, according to the size and purposes of the laboratory. For the com- 
 mon operations of quantitative analysis, the chemical balance first described is 
 alone necessary. A larger balance will, however, be almost indispensable in water- 
 analyses, and in many physico-chemical investigations, and will always be ad- 
 vantageous by allowing the use of large evaporating dishes and vessels, or the 
 weighing of a series of drying tubes, or other apparatus as a whole. But a laboratory 
 is not complete without an assay balance, which will perform all light weighings with 
 an accuracy and expedition impossible in a large balance. 
 
 When the employment for balances is very extensive, it will be best accommodated, 
 not so much by increasing the number of balances as by classifying them, assigning to 
 
BALANCE. 
 
 487 
 
 each its proper work, and strictly adhering to rules once laid down. Where there are 
 two balances of the same kind, it is obviously best to retain one for the more refined 
 purposes, and make the other perform all common work, and two balances thus used 
 may serve better than half a dozen indiscriminately worked and spoiled, 
 
 Mechanical Theory of the Balance. 
 
 Properly to understand the action of a balance, it must be considered both statically 
 and dynamically, that is to say, both when the beam is at rest and while it is in 
 motion ; for the oscillations of a good balance are almost as valuable an indication as 
 its position at rest. 
 
 First, however, to show the conditions of equilibrium, let (fig. 85) be the central 
 axis of suspension of a balance, and EE', the extreme axes of suspension not neces- 
 sarily in the same straight line with O. Suppose equal weights, each = P', to act at 
 E and E', including of course the 
 
 whole weight of the burthen, pans, Fig. 85. 
 
 aud other objects suspended at the 
 extreme axes. Then the whole 
 weight 2P' may be conceived as 
 acting at G', the middle point of 
 the line EE'. Assuming the axis 
 to be properly placed at equal dis- 
 tances from E and E', the line OG' 
 will be perpendicular to EE', and 
 the weight of the beam, say P, will 
 act at its centre of gravity, which 
 is, or should be, some point G, on 
 this line or its prolongation. 
 
 Lastly, let some small additional 
 weight p act at E. The beam can 
 not now remain horizontal, but may V , 
 again rest in equilibrium in some v 
 
 position inclined at an angle, say 0, to the horizontal line NN'. Drawing E N, E' N', 
 Gr A,G' B, perpendicular to NN', we must have, according to the principle of the 
 lever, the sum of the moments of the forces on one side equal to that on the 
 other, or 
 
 2F . OB + P . OA = p . ON = XBN-BO) 
 Or, substituting in terms of 0, we have 
 
 2P' . OG-' . sin 6 + P. OG sin = p . G'E . cos - p . OG' . sin 
 'iQ p . G'E 
 
 tan 9 
 
 cose (2F+^)OG'+ P.OG 
 
 Now for small values, tan 6 varies very nearly as the angle of deviation 8, which angle 
 may be regarded as the true measure of the sensibility of the balance, and p being 
 quite inconsiderable compared with 2P' and P, we*may say that the sensibility is in- 
 creased by increasing the length of the beam, diminishing the weights of the beam and 
 load, or diminishing the distances of Gr and Gr ' from the axis 0, and also that the sensi- 
 bility varies very nearly in the direct or inverse ratio of these changes. 
 
 Again, the force tending to restore the beam to the horizontal position when dis- 
 turbed is sin (2P' . OG' H- P . OG). This is the measure of the stability of a balance, 
 a certain degree of which is required to render a balance useful. Now with given 
 weights P and P', and for any given deviation 0, the force of stability will entirely 
 depend upon the positions of G and G', and the following are the cases which arise. 
 
 1. The extreme points of suspension EE' may be so placed that G' falls above 0. 
 The stability is sin (P . OG - 2P' . OG'), which for a certain value of P' will be nothing, 
 so that the whole system will be suspended at the centre of gravity, and the beam 
 being disturbed will have no tendency to return, but will rest in neutral equilibrium, 
 indifferently in any position. 
 
 For a greater value of P', the force will be negative, and the equilibrium unstable, 
 that is to say, the beam when loaded beyond a certain degree will overset, and per- 
 manently sink down on one side without a tendency to return, even when the weights 
 on the two sides are not unequal. A balance of such construction then, could only be 
 used for weights of a certain smallness, and its sensibility would increase and its 
 stability decrease with its load. 
 
 2. If G fall above and G' below, the stability is sin (2P' . OG-P'. OG), which 
 will be nothing for a certain value of P', and negative for smaller values. The balance 
 
 ii 4 
 
488 
 
 BALANCE. 
 
 then would be stable only when P, the load in the pans, is not less than a certain 
 magnitude. 
 
 3. If G coincide with (OG = 0) and G' fall above 0, the balance is always un- 
 stable and useless. 
 
 4. If G- coincide with and G' fall below O, the stability is 2P' . OG' . sin 9, which 
 depends entirely upon the weight placed in the pans. 
 
 5. Now let G-' coincide with 0, (OG' = 0) the three points EOE' being in a straight 
 line, but let G fall below 0. The stability is sin Q . P . OG, which for a given value of OG, 
 
 is constant. Also tan = ' ~ which depends only on p. In a balance of such 
 
 construction, all weights may be weighed indifferently and with equal accuracy, and 
 any required degree of sensibility may be obtained by duly regulating the length 
 of OG. 
 
 6. Let G and G' coincide ; then sin 6 . OG(2P' + P) is the measure of stability, and 
 
 is proportional to the weight to be moved. Also tan = (2P F +P~+ K)G var * es 
 inversely as the total weight moved. 
 
 In any case of stable equilibrium, it will be easy to determine the position of the 
 
 centre of gravity (say g) of the whole system from, the formula Off = - a\^p> p \ 
 
 by observing the deviation for several values of p, and for a given load P' in the pans. 
 A different value will be found for Og for each different value of P', unless the balance 
 be constructed in the sixth mode described above. In a sensitive balance Og, will 
 probably not exceed lo ^ go part of an inch. 
 
 "We may now consider the balance in the character of a compound pendulum, select- 
 ing for this purpose the fifth mode of construction above described. Thus if G, the 
 centre of gravity of the beam (fig. 86), be vertically under 0, and the weights in the 
 
 
 pans be equal, the system will be at rest. But now suppose a small additional weight 
 p added at E : the centre of gravity is no longer at G but say at g, nearer to E by a 
 distance (G^), such that 
 
 0.GE 
 
 Since g is not vertically under 0, the beam cannot remain at rest, but will vibrate 
 about the perpendicular line OG, and the point C of the index fixed to the beam will 
 describe the arc CO', subtending the angle 20. 
 
 The velocity of the beam is greatest, of course, when g is vertically under 0, and 
 being proportional, as proved in the theory of dynamics, to the angle 6, is also 
 nearly proportional to p. Hence when the deviation is small, the greatest velocity which 
 the beam attains may be observed as an indication of p. 
 
 As in any other pendulum, the length of time occupied in a vibration is almost the 
 same whether the vibration be great or small, as may easily be observed to be the 
 case. 
 
 Fully to understand the motions of a beam, it would be necessary to determine its 
 moment of inertia round the axis, which is the sum of the moments of each particle, 
 the moment of inertia being the mass of a particle multiplied by the square of its 
 distance from the axis. The velocity of the beam depends on the proportion of the 
 force of stability or the force of disturbance, and the moment of inertia, which it has 
 
 
BALANCE. 489 
 
 to overcome. Hence the force of stability alone gives a very imperfect idea of the 
 motion of the beam, which will be slower the greater the weight in the pans, espe- 
 cially if the force of stability itself be not increased, as in the sixth case, by increasing 
 the weight in the pans. 
 
 The mechanical problem of the balance is not so simple as may at first sight ap- 
 pear, and has not, so far as we are aware, been properly considered dynamically. The 
 problem of the compound pendulum, will be found best treated byPoisson (Traite 
 de Mechanique, t. ii. c. i. 3). Euler, in the Petersburg Commentaries (x. 3), appears 
 to have shown the statical conditions of a balance. 
 
 It will be apparent that, the length of the beam remaining constant, the properties 
 of statical sensibility and stability are reciprocal to each other. By increasing the 
 length of the beam, indeed, the balance is said to be rendered both more sensible and 
 stable. But in reality the weight of the beam must be increased in a far greater pro- 
 portion than its length, so that its motions will become nmch slower, to say nothing 
 of the less convenience of a large instrument. 
 
 The construction in which the three axes are in one straight line, is undoubtedly the 
 most perfect, and is especially suitable if the vibrations are to be used, as afterwards 
 described, for the determination of fractional weights. But a balance in which the 
 centre axis is slightly above the line of the extreme axes, will not become so much 
 slower in its movements when heavily laden, and will yet indicate at least as small a 
 fraction of its load when this is great, as when small. Hence such a balance will, we 
 think, be suitable for most purposes. It is necessary however to bear in mind, that 
 when the three points of suspension are not in one straight line, equilibrium may 
 subsist when the beam is not horizontal, and the weights in the pans are unequal. For 
 when the angle EON is greater than the angle E'ON', ON and ON' are unequal, and 
 we may have equilibrium for P' . ON = P" . ON', where P' and P" are unequal weights 
 in the pans. 
 
 The truth is, that a balance must be so adjusted in its length, strength, weight, 
 and relative position of the centres of suspension and gravity, as to combine the exact 
 degrees of sensibility, stability, or quickness, and capacity for bearing weights, which 
 its special employment requires. In this adjustment, the chief skill of the balance 
 maker consists. Diminution of weight of the beam is an unqualified advantage, as long 
 as the strength is sufficient. Thus the employment of aluminium in the construction of 
 balances, will be of great advantage when accomplished ; but an aluminium beam, 
 which we have seen, was stated not to be trustworthy in point of strength and in- 
 flexibility. 
 
 The impediment to the free motion of a beam, is usually stated vaguely to be the 
 friction at the knife edges. But although friction or adhesion may be of some im- 
 portance, the variation in the length of the arms has really a much greater effect. 
 Thus, suppose, as is generally the case, that the knife-edges, instead of being perfectly 
 sharp or round, terminate in very narrow planes (fig. 87), of the width y. If the 
 
 iff. 87. 
 
 distances between the middle points of the knife edges be a, the real lengths of the two 
 arms of the lever when the beam is not horizontal, will be a x, and a + x, consequently 
 weights which have the ratio of a + x, and a x, may be apparently in equilibrium. 
 In order then that a balance with a 20-inch beam may indicate the millionth part of 
 
 1,000,000 a x 10 
 
 its load, we must at t te most have j^b^oi = TVx r * = 2,000,001 mch; thm 
 the same length too, the two arms of the beam must be adjusted to equality if the 
 balance is to be accurate within one millionth part of its load. Now this length, 
 being inappreciable in a common microscope, will give some idea of the skill required 
 in a balance-maker. We are thus prepared too for the statement of Prof. Miller 
 (see reference below), that he not only detected a difference in the expansion of the arms 
 of his balance by a change of temperature, owing to some difference in the quality of the 
 metal, but that temperature also affected the sensibility of the instrument, which 
 resembled an over-compensated pendulum, from the difference of expansion of the steel 
 knife edge and the brass in which it was fixed. 
 
 The resistance of the air has but an inconsiderable effect upon a balance. 
 
490 BALANCE. 
 
 ELIMINATION OF ERRORS. Since every balance however good, requires some dtjtnilc 
 weight to cause it to turn, a difference of this amount may exist between any two 
 weights which are apparently in equilibrium. Thus if a balance when loaded refuse 
 to turn with anything less than i of a grain, it is an even chance, that two weights 
 which do not cause the balance to move, differ by ^ of a grain or more. In the 
 common use of a balance, the turning-weight (scrupulum in Latin), will give the 
 limit of accuracy of the weighings. Let this turning-weight be Ax; then the balance 
 . will turn when the weights x + Ax and x are in the pans. It will also probably turn 
 in the opposite direction when x Ax is substituted for x + Ax, because the balance, 
 unless a very bad one, will turn as easily one way as the other. Thus the mean of 
 x + Ax and x Ax, will be the true weight required, nearly freed from the error of in- 
 sensibility. This operation may be resorted to when a balance has become insensible by 
 age but is otherwise good, and may be very easily performed by the use of a rider 
 weight. But the .delicacy of balances is generally ahead of what is required of them. 
 Any good balance should weigh with certainty to the 100 1 000 part of its load, but 
 there are as yet few chemical operations which can pretend to an accuracy of 
 
 The only other kind of error to which the determinations of a balance are essentially 
 liable, is that caused by the inequality of the arms : for the extreme edges can never 
 be adjusted at perfectly equal distances from the centre edge. This error is avoided 
 entirely and without trouble, in the ordinary operations of the chemist, by taking care, 
 during each analysis or series of experiments, to use, say the left pan invariably for 
 the objects to be weighed, and the right pan for the weights. The apparent weights 
 of all the objects are thus increased or diminished in precisely the same ratio, and 
 the comparative results are therefore unaffected by the real falsity of the balance. 
 
 Thus if a be the length of the arm bearing the weight-pan, and b the length of that 
 bearing the object-pan, then objects of the true weights, x, y, z, &c. will appear to 
 
 weigh x, y, z. but the ratios a? : y \z are the same as x : y : z, the ratios 
 * a ' a*' a ' a a y a 
 
 of the true weights. That this elimination of error may be perfect, it is obviously 
 necessary that no weights be placed in the object-pan, as is sometimes done, for the 
 purpose of making up a given weight in the easiest manner by subtraction. 
 
 There are, however, two well known methods for obtaining the true absolute weight 
 of an object, even by a false balance. The first, introduced by Gauss, proceeds by 
 simply weighing the object alternately in one pan and the other. If the apparent 
 weights are the same, they are each the true weight, or the balance is appreciably 
 correct. If not, the geometric mean is the correct weight, and is found by multiplying 
 the true apparent weights together, and taking their square root. For if the true 
 
 weight be x, and a, b be the lengths of the balance arms as before, -? x, and - x will 
 be the apparent weights in the respective pans, and x = ./ - x . - x. if the appa- 
 rent weights be very nearly equal, their common arithmetic mean-/Y# + -x\ is 
 
 quite close enough to the truth. Thus the arithmetic mean of 1-000 and 1-001 is 
 1-0005, and the geometric mean 1-0004998 ... . 
 
 The second method for ascertaining absolute weights free from all error, is that 
 known as the method of substitution, ascribed by French writers to Borda, but pro- 
 bably due to the Pere Amiot. If there be one weight C in the weight-pan, and other 
 weights X, Y, Z, &c. be in succession placed in the object-pan, and the balance is yet 
 
 always in equilibrium, it is evident that X = Y = Z = C. Thus we prove the 
 
 perfect equality of X, Y, Z, although each of these may differ in an unknown degree 
 from C, owing to the inequality of b and a, the lengths of the balance-arms. 
 
 To compare the weights of any two objects by this method, counterpoise the greater 
 with the weight C, made up of shot, tin-foil, wire, or any convenient substance. 
 Then substitute the second object for the first, and observe how many small weights 
 must be added to the pan to restore equilibrium with (7. The only errors which can 
 affect such a result will be that of insensibility, and any error which may arise from 
 a minute change of the edges of suspension during the substitution ; but these errors 
 may be eliminated by taking the mean result of many such operations, a new counter- 
 poise being adjusted each time. 
 
 But when important weighings have to be made with the most rigorous accuracy, as 
 in the comparison of standard weights, the method of vibrations must be resorted to. 
 This being a process of pure observation, as distinguished from one of adjustment, 
 
BALLUS BALSAM. 491 
 
 admits of unlimited approach to absolute exactness, just as the difference of two 
 standard yards may be ascertained to the % o 000 part of an inch, although it would 
 be impossible to make two yards agree within ten times that quantity. 
 
 The paper by Prof. W. H. Miller, on the Construction of the New Imperial Standard 
 Pound (Phil. Trans, cxlvi. (1856) p. 753), should be studied by all engaged in exact de- 
 terminations of weights, but a more explicit account of the method of vibrations will 
 be found in Kupffer's work, "Travaux de la Commission pour fixer les Poids et 
 Mesures de Eussie," St. Petersburg, 1841. Prof. Miller's mode of observing the os- 
 cillations appears to be the most eligible. His balance had a very light ivory scale, 
 about half an inch long, divided into spaces of about ^ inch, attached to the right 
 end of the beam. This scale, as it moved, was viewed through a fixed compound 
 microscope, having a single horizontal wire in the focus of the eye-piece. A still more 
 delicate mode of observation, is by a small mirror fixed to the beam, in which the 
 reflection of a divided scale is viewed through a fixed telescope, as in the instruments 
 of a magnetical observatory. 
 
 The weights to be compared being very nearly in equilibrium, the balance when 
 released oscillates slowly through a very small arc, and the extreme points of each 
 excursion are to be observed. Supposing the readings thus observed to be E', E 2 , E 3 , E 4 . 
 
 Then - is the position of equilibrium of the beam : for, by the 
 
 nature of the pendulum already considered, the excursions will be as far on one side as 
 on the other. In this expression, E 2 and E 3 are doubled, because they are the end of 
 one half vibration and the beginning of another. Prof. Miller usually rejected the 
 first reading because it is apt to exhibit slight irregularities, and his result was derived 
 
 from . This observation completed, a small known weight is added to 
 
 the lighter of the weights compared, and the new position of equilibrium which the 
 beam tends to take up, is observed by a new set of readings. Now the deviation from 
 the horizontal position in a good balance being very nearly proportional to the weight 
 causing it, we obviously learn from the angular difference of the two positions of the 
 beam, the deviation corresponding to a given small weight. Hence we learn by 
 the simplest calculation the difference of weight corresponding to the deviation in the 
 first observation. 
 
 The method of weighing by reversal was found more convenient by Prof. Miller, 
 than that by substitution, and was thus practised. 
 
 The nearly equal weights P and Q to be compared, were weighed directly against 
 each other, but repeatedly reversed, and the balance was so adjusted by a small con- 
 stant weight placed in one of the pans or on the beam, that on interchanging P and Q, 
 the position of equilibrium was still near the middle of the scale. Then if (P, Q) be 
 the reading of the scale in the position of equilibrium when P is in the left hand pan, 
 and Q in the right hand pan, and (Q, P) the reading when Q is in the left hand pan, 
 and P in the right hand pan ; then 2Q, = 2P + m ((P, Q) - (Q, P)), where m is the 
 weight equivalent to one degree of deviation on the scale. 
 
 In the determination of the equivalents of the elements, and in many physico- 
 chemical determinations, it is to be hoped that chemists will soon have to tax to the 
 utmost these refined methods of weighing. 
 
 On the balance generally, the reader may further consult Biot, Traite de Physique, 
 i. 9; Pouillet, El. de Phys. i. 66; Ann. de Chim. xxxvi. 3; Jury Eeports on the 
 Exhibition of 1851, pp. 257 262; Phil. Trans, cxvi. pt, 2, p. 36. For a description 
 of Napier's "Automaton-balance" for weighing coin, see tire's Dictionary of Arts, 
 Manufactures and Mines, i. 245. W. S. J. 
 
 BAXiXilTS, or BAZiAXS RUBY. A variety of spinelle, varying in colour from 
 reddish- white to pale red. 
 
 BAXiXiESTEROSXTE. A variety of iron pyrites, found in Asturia and Gallkia, 
 Specific gravity 4'75 to 4'90. 
 
 B AXiXiOOXf . Eeceivers and flasks of spherical form are sometimes called balloons. 
 
 BAXiSAM. This term, originally confined to a single substance, viz. Balm of 
 Gilead, Mecca Balsam, or Balsam of Judea, is now extended to a variety of products, 
 more or less resembling that body, but exhibiting considerable diversity of composition 
 and properties. They are viscid, aromatic liquids, which exude from growing plants, 
 either spontaneously, or from incisions made for the purpose. 
 
 Balsams are mixtures of resins with volatile oils, the resins being produced from the 
 oils by oxidation, so that a balsam may be regarded as an intermediate product be- 
 tween a volatile oil and a perfect resin. They may be divided into two groups, the 
 one including those of purely oleo-resinous character, viz. Copaiba balsam, Mecca bal~ 
 
i92 BALSAMS. 
 
 sam, and the balsams or turpentines of coniferous plants ; the other group, includ- 
 ing those which contain cinnamic acid, such as Peru balsam, Tolu balsam, Liquid- 
 ambar, and Storax. Benzoin and Dragon's-blood are sometimes also classed among 
 balsams ; but they are more properly resins ; the true balsams are liquids more or less 
 viscid, and yield volatile oils by distillation with water. The balsams of the second 
 group yield by dry distillation, cinnamate or benzoate of ethyl or methyl, and accord- 
 ing to Scharling, these products, or perhaps others not previously existing in the 
 balsams, may be formed from them by the action of aqueous alkaline leys. 
 
 Balsams of the First Group : Oleo-resins. 
 
 CANADA BALSAM or CANADIAN TURPENTINE, Baume du Canada, is the produce of 
 Abies balsamea (Dec.), a coniferous tree growing in Canada, Virginia, and Carolina. 
 It collects in vesicles under the bark, and is obtained by making incisions in the 
 stem. It is either colourless or slightly yellowish, rather mobile, but tenacious and 
 capable of being drawn into threads, turbid when fresh, but soon becomes perfectly 
 transparent when left at rest. It turns the plane of polarisation of a luminous ray to 
 the right, and has an index of refraction equal to T532. It dries up to a hard varnish 
 when exposed in thin layers to the air for about forty-eight hours, and gradually 
 thickens, even in closed vessels. Its power of hardening, its transparency, and its 
 peculiar refractive power, which is nearly the same as that of crown glass, renders 
 it very useful as a cement in the construction of optical instruments. In some coun- 
 tries it is used as a medicine ; when taken internally, it imparts a nutmeg odour to the 
 urine. 
 
 Canada balsam distilled with water, yields a volatile oil, of balsamic odour, agree- 
 ing in composition with oil of turpentine (Wirzen), and like that oil, turning the 
 plane of polarisation to the left (Blot); it also leaves a resinous cake, brittle after cool- 
 ing, and consisting of a mixture of several substances. The balsam is partially soluble 
 in alcohol, a granular resin remaining undissolved. 
 
 Canada balsam contains, according to Bonastre (J. Pharm. viii. 572 [1822]), 18*6 
 per cent, volatile oil, 40 - resins easily soluble in alcohol, 33*0 resin sparingly soluble 
 in alcohol, together with 8*4 caoutchouc and bitter extractive matters soluble in water. 
 The sparingly soluble resin is described as dry, friable, heavier than water, difficult to 
 melt, and becoming electrical by friction. According to Caillot (J. Pharm. xvi. 436 
 [1830]), the balsam contains two neutral resins, one called abietin (seep. 1), being 
 crystallisable and easily soluble in alcohol of 0*824, the other white, pulverulent, with- 
 out crystalline form, very little soluble in alcohol of 0'824, or in rock oil, or potash- 
 ley, and closely resembling the sparingly soluble resin obtained from other species of 
 abies ; also an acid resin, which forms a coherent paste when mixed with i of its 
 weight of magnesia, and imparts to Canada balsam the property of forming a white soap 
 with potash. According to Wirzen (De balsamis ct prcesertim de balsamo Canadense 
 Dissertatio, Helsingforseae, 1849), Canada balsam contains 16 per cent, of volatile 
 oil, 30 pts. of a resin o, soluble in boiling alcohol of 0'833, and containing C 40 H 32 0* 
 (78-31 per cent. C and 10*08 H), 33 pts. of another resin 0, insoluble in hot alcohol, 
 but soluble in ether, and containing C^H'^O 7 ; and, lastly, 20 pts. of a resin 7, in- 
 soluble in alcohol and ether. Wirzen's a resin is probably a mixture of abietin with 
 an acid resin. 
 
 A balsam exactly resembling the preceding, excepting that it has a darker colour, 
 is obtained from Abies canadensis (Link). Canada balsam is distinguished from all 
 other varieties of turpentine by its peculiar odour, its perfect transparency and ducti- 
 lity, and the facility with which it hardens when exposed to the air. Strasburg 
 turpentine, from Abies pectinata, which very much resembles it, is distinguished by its 
 optical laevo-rotatory power; and Venice turpentine (from Larix europad), by its easy 
 and complete solubility in alcohol of ordinary strength, and its indifference towards 
 calcined magnesia. 
 
 The other balsams, or turpentines, derived from coniferous plants, will be described in 
 the article TURPENTINE. 
 
 COPAIBA or COPAIVA BALSAM. Balsamum Copaivce, Baume de Copahu. This 
 balsam is produced by several species of Copaifera (order Casalpincce), particularly by 
 Copaifera bijugal, Willd., C. muUijuga, Hayne, C. Gruianensis, C. Langsdorfii, and C. 
 Jacquini, Desf., which are indigenous in Brazil, Peru, Mexico, and the Antilles. It is 
 obtained by making incisions or perforations in the trees during rainy weather, and 
 flows so abundantly that a single incision often yields 12 pounds of the balsam. 
 
 Copaiba balsam consists of several resins dissolved in a volatile oil, the amount and 
 nature of the resins varying considerably in balsam from different suurces. There are 
 three principal varieties, the Brazilian, the Antillian and the Columbian. 
 
 Brazilian copaiba is light yellow, generally transparent, of various degrees of con- 
 
BALSAM OF COPAIBA. 493 
 
 sistence, from mobile to syrupy, and of specific gravity ranging from 0-920 to 0'985. 
 It has a peculiar, aromatic, disagreeable odour, and a persistently bitter and irritating 
 taste. By exposure to the air, it becomes darker in colour, of the consistence of tur- 
 pentine, heavier than water, and ultimately solid and inodorous. When heated in 
 contact with the air, it takes fire and burns with a bright, but very smoky flame. The 
 balsam from the Antilles differs from the Brazilian by its more viscid consistence, 
 darker colour, imperfect transparency, and turpentine-like odour. Columbian copaiba 
 is distinguished by its turbidity, arising from suspended particles of resin, which are 
 deposited as a crystalline crust when the balsam is left at rest. 
 
 The chemical examinations hitherto made of copaiba balsam relate chiefly to the 
 Brazilian, of which two varieties are distinguished. 
 
 I. Copaiba balsam chiefly containing acid resins. This variety, which was for- 
 merly the only one known, is distinguished by the following characters : It is inso- 
 luble in water, but imparts to the water its taste and smell. It dissolves in all pro- 
 portions in absolute alcohol, in ether, and in oils, both fixed and volatile ; the alcoholic 
 solution, however, is often rendered turbid by the separation of resinous flakes. 
 Alcohol of 90 per cent, dissolves a large quantity of it ; alcohol of 80 per cent, only 
 
 1 to ^ of its own weight. Mixed with an equal weight of fixed oil, it dissolves in 
 
 2 pts. of 90 per cent, alcohol, the fixed oil separating only on the addition of a con- 
 siderable quantity of alcohol. It absorbs chlorine gas, becoming turbid at the same 
 time, from formation of hydrochloric acid. With strong sulphuric acid, it assumes a 
 red colour and viscid consistence, with evolution of sulphurous anhydride, and an 
 odour of oil of amber. Strong nitric acid acts upon it with violence ; dilute nitric 
 acid more quietly, forming a hard yellow resin, which dissolves partially in the acid, 
 and a yellow bitter substance insoluble in water and in alcohol. Distilled with 2 or 3 
 per cent, of its weight of strong sulphuric acid or with hypochlorite of calcium, it yields 
 a volatile oil of fine blue colour (Lowe, Pharm. J. Trans, xiv. 65) ; the same oil is said 
 to be produced by the action of acid chromate of potassium. Three pts. of the balsam 
 mixed with 1 pt. of potash-ley containing | pt. of hydrate of potassium, yield a clear 
 liquid, which does not lose its transparency when mixed with alcohol or with a small 
 quantity of water, but becomes milky on addition of a large quantity of water. A 
 larger quantity of caustic potash-ley added to the clear liquid, throws to the surface a 
 transparent copaiba-soap, which forms a turbid solution with a large quantity of' 
 water, or with absolute alcohol, but dissolves completely in ether or in hydrated 
 alcohol When an alcoholic solution of the balsam is mixed with dilute potash or soda- 
 ley, a volatile oil rises to the surface, while the resulting compound of resin and alkali 
 remains dissolved in the hydrated alcohol. This process may be used for the prepara- 
 tion of the volatile oil. Five pts. of the balsam form with 2 pts. of aqueous ammonia 
 of specific gravity 0-921, a clear mixture, from which a larger quantity of ammonia 
 separates a soapy compound. A mixture of 9 pts. of the balsam and 2 pts. aqueous 
 ammonia well shaken up and left at rest at + 10 C., gradually yields a crystalline 
 deposit, consisting of the resinous acid of the balsam. The balsam likewise combines 
 readily with magnesia. It dissolves completely ^ of its weight of calcined magnesia, 
 and when mixed with ^ of its weight of that substance, thickens to a stiff paste in the 
 course of a few days; with | in a few hours. Similarly with quick lime. Carbonate 
 of magnesium likewise forms with 4 pts. of the pure balsam at mean temperatures 
 (15 C. or 60 F.), a clear viscid solution. 
 
 The balsam distilled with water yields a volatile mobile oil, C 5 H 8 , possessing in a 
 high degree the peculiar odour of the balsam, and forming a crystalline compound 
 with hydrochloric acid (see COPAIBA OIL), while in the retort there remains a mass 
 of brittle resin, which is resolved by treatment with rock-oil, into a crystallisable por- 
 tion soluble in that liquid (the o resin of Berzelius), and an insoluble unctuous sub- 
 stance (0 resin of Berzelius). The crystallisable resin has the formula C ao H 30 2 , and 
 from its property of reddening litmus and uniting readily with acids, is called copaivic 
 add. The crystalline deposit which separates from the turbid balsam, is, according to 
 Fehling's investigation, a resinous acid containing C 20 H' 28 3 . It is to these two 
 resins that the peculiar reactions of the balsam with bases are due. The soft resin 
 is, perhaps, formed by oxidation of the volatile oil in the air, and appears to have but 
 a very slight amnity for bases, inasmuch as when isolated it dissolves but slowly, and 
 only, with the aid of heat, in potash and ammonia, forming a turbid solution. (See 
 COPAIBA KESINS.) 
 
 Besides these essential constituents, the balsam likewise contains occasionally a 
 small quantity of water, and, according to Durand, small quantities of extractive 
 matter, acetic acid (perhaps also succinic acidX and a fatty substance, which re- 
 mains behind when the balsam is dissolved in alcohol of specific gravity 0-842 ; also 
 traces of chloride of calcium. The followiw are analyses of this variety of copaiba 
 balsam: 
 
494 BALSAM OF COPAIBA. 
 
 Stoltze.* Guibourt.f Gerber.t 
 
 Fresh balsam. Old balsam 
 
 Volatile oil . . 38-00 45'0 41'0 31-97 
 
 Alpha-resin . . 52-75 53-9 51'38 52'68 
 
 Beta-resin . . 1'66 1-1 2'18 11-15 
 
 Water and loss . . 7'59 5-44 4-10 
 
 100-00 100-0 100-00 100-00 
 
 II. Copaiba Balsam, containing only neutral resins. PARACOPAIBA BALSAM. This 
 variety, which is of recent introduction, is distinguished from the former by its much 
 greater mobility. In odour and taste it agrees with the preceding, but, according to 
 Posselt (Ann. Ch. Pharm. Ixix. 67), behaves in a totally different manner with sol- 
 vents and with bases. With alcohol, in any proportion, it forms a turbid mixture. 
 Potash and ammonia also form with it turbid liniments, which, when left at rest, 
 deposit the balsam in its original state. It does not thicken with magnesia. The 
 volatile oil, paracopaiba-oil, which it yields by distillation with water, is distinguished 
 from the copaiba-oil above-mentioned, by its viscidity, its sparing solubility in abso- 
 lute alcohol, and especially by not forming a crystalline compound with hydrochloric 
 ucid. The resinous cake, brittle in the cold, which remains after the volatile oil has 
 been distilled off, is resolved by cold alcohol into a soluble portion, which separates 
 on evaporation of the alcohol, in drops that gradually solidify in amorphous masses, 
 and another resin, which dissolves only in boiling alcohol and in ether, is difficult to 
 fuse, and likewise uncrystullisable. Neither of these resins exhibits any acid reaction 
 in the state of solution, or forms compounds with bases (see COPAIBA RESINS). One 
 hundred pts. of the Brazilian balsam examined by Posselt, contained 82 pts. of volatile 
 oil, and 18 pts. resin, the greater part of which was soluble in cold alcohol. 
 
 The two varieties of copaiba balsam just described, the first of which, from its be- 
 haviour with magnesia, is called solidifiable balsam, must be regarded merely as 
 types which are, perhaps, not the only ones and may vary greatly in the proportion 
 of oil and resin, and therefore in consistence. Oberdorffer (Arch. Pharm. [2] xlv. 
 172) found in three varieties of mobile copaiba balsam of the first variety : 
 
 I. II. in. 
 
 Volatile oil . . . .60 58 54 
 
 Resins .... 40 42 46 
 
 The following proportions of oil and resin have been found in several balsams of 
 unknown origin : 
 
 Ulex. Stockhardt.li Procter.f 
 
 Specific gravity 
 
 Volatile oil 
 Resins 
 
 The amount of volatile oil was estimated either by the loss of weight which the 
 balsams suffered by boiling with water (I. to VI.), or by continued heating to 120 C. 
 (248 F.), till the weight remained constant (VII. to XI). The balsams IV. to VI. 
 were mobile and are not further distinguished ; VII. and VIII. are mobile balsams of 
 the second variety ; IX. to XI. viscid balsams of the first variety. 
 
 According to Procter, the proportion of oil varies with the age of the trees, the 
 youngest trees yielding the most liquid balsam. The acid resins appear to be formed 
 in the plant itself, while the soft resin (j8 resin) is produced by the oxidation of the 
 volatile oil, and consequently increases in amount with the age of the balsam, espe- 
 cially when it is kept in loosely closed vessels ; this is in accordance with the results 
 of Oberdorffer's analyses just quoted. 
 
 Copaiba balsam is used in the preparation of lac- varnishes and tracing paper ; but 
 its chief application is in medicine, as a remedy in diseases of the urinary passages. 
 It is not known with certainty to which constituent of the balsam the peculiar physio- 
 logical action is due ; but it does not appear to reside especially in the volatile oil ; for 
 in many places, the resin completely freed from oil is successfully used in medical 
 practice, instead of the balsam in its original state. Whether the more oleaginous 
 variety, containing only neutral resins, which is of recent introduction, is capable of 
 exerting the same action as the more viscid and acid variety, which has long been in 
 use, is not yet known. 
 
 Copaiba balsam is often adulterated, especially with fixed oils and turpentines. Of 
 
 * Berliner Jahrb. f. Pharm. xxvii. 179. f Pharm. J. Trans, x. 172. 
 
 J Brandos Archiv, xxx. 147. Arch. Pharm. cxxii. 14. 
 
 I Arch. Pharm. xxxvni. 12. ^ Pharm. J. Trans, x. 603 
 
 IV. 
 
 0-928 
 
 s~- 
 
 V. 
 
 * N 
 
 911. 
 
 VII. 
 
 0-916 
 
 VIII. 
 
 0-956 
 
 IX. 
 0-983 
 
 X. 
 
 0-985 
 
 xi 
 
 0-986 
 
 90 
 11 
 
 58 
 
 42 
 
 56-5 
 43-5 
 
 80 
 20 
 
 65 
 35 
 
 50 
 50 
 
 35 
 65 
 
 34 
 
 64 
 
BALSAM OF MECCA. 494 
 
 late years East Indian wood-oil (also called Crurjun balsam, or capivi), which closely 
 resembles copaiba balsam in taste and smell, has been introduced as a substitute for it. 
 This oil may be easily distinguished by its property of becoming gelatinous when 
 heated to 130 C. (268 F.), whereas pure copaiba balsam becomes more fluid when 
 heated. 
 
 The presence of fixed oils in copaiba balsam may be detected by the following 
 methods : 1. By placing one or two drops of the balsam on paper, and evaporating it 
 at a very gentle heat. The pure balsam then leaves a hard, sharply defined varnish- 
 like spot, whereas if any fixed oil be present, the spot is soft and surrounded with a 
 circle of fat (Berzelius). 2. The pure balsam, boiled for some hours with water in an 
 open vessel, leaves a resin which becomes brittle on cooling : fixed oils render this 
 residue soft or greasy. 3. The fixed oils remain behind when the balsam is dissolved 
 in 8 pts. of alcohol of 90 per cent, (a smaller quantity of alcohol of that strength 
 would leave some of the balsam undissolved, p. 493). This last method will not in- 
 dicate the presence of castor-oil, which is itself soluble in alcohol; neither will it detect 
 the presence of less than 10 per cent, of other fixed oils. Turpentine and oil of tur- 
 pentine may be recognised by their odour, especially when the balsam is dropped upon 
 a metal plate. 
 
 All other methods of testing copaiba balsam are founded on the amount of acid 
 resins contained in it, and relate to the first variety (p. 493). This officinal balsam 
 may be regarded as genuine when, besides exhibiting the characters above mentioned 
 (p. 493), it forms a clear or nearly clear solution with alcohol, yields by distillation 
 with water, not more than 45 per cent, of volatile oil ; forms a clear solution with f of 
 its weight of aqueous ammonia of specific gravity 0'921, and when mixed with ^ of 
 its weight of calcined magnesia, gradually forms (in twenty-four to forty-eight hours) 
 a plastic paste. (Handwork d. Chem. 2 te Aufl. ii. 634.) 
 
 MECCA. BALSAM or BALM OF GILEAD. Opobalsamum verum s. zileadense. Bourne 
 de la Mecque, de Judee, ou du Caire. This balsam is the produce of the Balsamo- 
 dendron gileadense or, Amyris gilcadensis, a shrub belonging to the terebenthaceous 
 order, native of Arabia Felix. There appear to be three varieties of it. The finest, 
 which is used only in the East, and has a peculiarly fragrant odour, is said to exude from 
 the flowers in clear colourless drops. An inferior sort exudes spontaneously, or from 
 incisions in the young branches of the plant. It is mobile, pale yellow, turbid like 
 almond syrup, has a very agreeable odour like rosemary and lemon, and a bitterish 
 sharp taste. When exposed to the air, it gradually hardens and loses its transparency. 
 The third sort, which is the most common, is obtained by boiling the wood and the 
 branches with water. It is somewhat more viscid than balsam of copaiba, becomes 
 white and soapy when rubbed in the hand, and when dropped upon water, forms a 
 film which is easily removed by a quill feather. Ordinary spirit of wine dissolves it 
 but partially, and leaves a transparent odorous substance, of which warm alcohol of 
 specific gravity 0'815 dissolves about two-thirds. The residue is a flocculent sub- 
 stance, which may be drawn out into threads. 
 
 Trommsdorff (Trommsd. Neues Journal, xvi. 62) found in a sample of this balsam, 
 30 per cent, of volatile oil, 64 per cent, of hard resin, 4 per cent, of soft resin, and 0-4 
 per cent, of bitter principles. The volatile oil was mobile, colourless, fragrant, and 
 had a rough taste ; dissolved in alcohol and ether, and with deep red colour in sul- 
 phuric acid, whence it was precipitated by water as a resin. It was also resinised by 
 nitric acid. The hard resin was honey-yellow, transparent, brittle, of specific gravity 
 1-333, softened at 44 C., and melted completely at 90. It dissolved with difficulty 
 in alcohol and ether at ordinary temperatures, easily with aid of heat ; it was likewise 
 soluble in oils, both fixed and volatile. It was altered by hot nitric, and sulphuric 
 acids, and appeared to combine with alkalis, forming compounds insoluble in free 
 alkali. The soft resin was brown and very glutinous, inodorous and tasteless ; melted, 
 when dry, at 112 C. It was insoluble in alcohol and ether, but soluble in oils, both 
 fixed and volatile. It was not attacked by alkalis or by strong sulphuric acid ; with 
 nitric acid, it swelled up and became friable. 
 
 According to Bonastre (Ann. Ch. Pharm. iii. 147), Mecca balsam contains in 
 100 pts. : 
 
 Fragrant volatile oil 10 pts. 
 
 Brown bitter extract, soluble in water and alcohol . . . 4 
 
 Acid resin, soluble in alcohol, and not hardening . . . 70 
 
 Stiff whitish-grey resin, sparingly soluble in alcohol . . 12 
 
 Acid substance and impurities . . . . . . 4 ,, 
 
 Mecca balsam was formerly used in medicine, but has now fallen into disuse on 
 account of its scarcity and dearness. In the East it is used internally as a tonic. 
 
495 BALSAM OF PERU. 
 
 Balsams of the Second Group, containing Cinnamic Acid. 
 
 LIQUIDAMBAB BALSAM is the produce of Liquidambar styracijlua, a large tree grow- 
 ing in Louisiana, Florida, and Mexico. There are two varieties of it, viz. : 
 
 1. Liquid liquidambar, or Oil of liquidambar, which is obtained by making inci- 
 sions in the tree, receiving the balsam immediately, in vessels which protect it from 
 the action of the air, and afterwards decanting the liquid from a portion of opaque 
 balsam, which settles to the bottom. It is a thick transparent oil of amber-yellow 
 colour, has an odour like that of liquid storax, but more agreeable, and an aromatic 
 taste, which irritates the throat. It contains a rather large quantity of benzoic or 
 cinnamic acid, and reddens litmus paper strongly. Boiling alcohol dissolves it, with 
 exception of a slight residue, and the filtered liquid becomes turbid on cooling. 
 
 2. Soft or white liquidambar is formed from the preceding by exposure to the air, as 
 when it runs down the stem of the tree and is left there to thicken. It resembles 
 very thick turpentine or soft pitch, is opaque and whitish, has a less powerful and 
 more agreeable odour than the preceding, and a sweet, perfumed, but irritating taste. 
 It contains a large quantity of benzoic or cinnamic acid. By continued exposure to 
 the air, it solidifies completely, and becomes nearly transparent. It was formerly sold 
 as white Peru balsam. (G-erh. iii. 386.) 
 
 PERU BALSAM. Balsamum peruvianum ; Sals, indicum. This balsam is the 
 produce of certain species of Myroxylum, or Myrospermum, growing on the Balsam 
 coast near San Sonate, in the state of San Salvador, Central America. There are three 
 varieties of it : 
 
 1. White Peru balsam. Obtained from the fruit of the tree by removing the 
 wings and the outer and middle integuments, and subjecting the inner coating, together 
 with the seed, to pressure. The balsam thus obtained is pale yellow, somewhat thick, 
 turbid and granular, and has an agreeable odour of melilot. When left at rest, it 
 deposits a solid crystalline layer. Cold alcohol or ether dissolves it but imperfectly ; 
 the same liquids when hot dissolve the greater portion. The alcoholic solution, when 
 left at rest, deposits crystals of myroxocarpin (<?.#.), of which also the crystalline 
 sediment above mentioned appears to consist. The ethereal extract of the balsam 
 leaves when evaporated a mixture of resin and fixed oil. The balsam distilled with 
 water, yields traces of a volatile oil and a volatile acid (Scharling). According to 
 Guibourt, there is another kind of white Peru balsam, which is identical with liquid- 
 ambar. 
 
 2. Dry Peru balsam, Balsamum peruvianum siccum, Opobalsamum siccum, is 
 said to be produced from the preceding by hardening in contact with the air. Ac- 
 cording to Weddell, it exudes spontaneously from the stem of a myroxylum. It is 
 reddish-yellow, translucent, hard, smells aromatic and like vanilla, melts when heated, 
 and burns with a smoky flame; 100 pts. of it contain, according to Tromsdorff, 12 pts. 
 benzoic (more probably cinnamic) acid, - 2 volatile oil, and 88'0 resin. 
 
 3. Black Peru balsam. Black balsam of San Salvador or San Sonate. Balsamum 
 peruvianum e. indicum nigrum. Baume de Peru noir. This, which is the ordinary 
 Peru balsam, has been known in Europe since 1580. It is said to be obtained by making 
 incisions in the stem of the trees, partially detaching a portion of the bark in such a 
 manner as to leave it still connected with the stem at the upper part, then thrusting woollen 
 rags between the bark and the wood, and warming the tree by making a fire round it. 
 Fresh incisions are then made higher and higher up, till the rags are saturated, the 
 process occupying ten or twelve days. The cloths impregnated with balsam are then 
 removed, and well boiled with water, and the balsam which sinks to the bottom is 
 freed from water, which it retains somewhat firmly, by several hours boiling under 
 water. It is then further purified by straining, and sent to Eiirope by way of Peru, 
 whence its name. (Copious details of the history and preparation of this balsam, are 
 given in Muspratfs Chemistry, i. 228 ; see also Ure's Dictionary of Arts, Manu- 
 factures and Mines, i. 248.) 
 
 Black Peru balsam is viscid but not glutinous, of dark brown colour, opaque in the 
 mass, bxit in thin layers perfectly transparent, with brown-red colour. Specific gravity 
 1-15. In contact with the air, it gradually thickens, but does not solidify. It has an 
 agreeable odour, like vanilla, a bitter, persistently irritating taste, and an acid reaction, 
 1000 parts of the balsam saturating about 75 of carbonate of sodium. 
 
 When heated, it takes fire and burns with a smoky flame. When distilled with water, 
 it does not yield any volatile oil, but the distillate contains cinnamic acid, which exists 
 in the balsam in the free state, and may be extracted by repeated boiling with water, 
 or by carbonate of sodium. Peru balsam mixes in all proportions with absolute alcohol ; 
 but the solution is not quite clear, and deposits a flocculent substance when left at rest. 
 Weaker alcohol dissolves it less easily, and leaves a residue of resin. It is also but 
 incompletely soluble in ether and in oils, whether fixed or volatile. It mixes without 
 
BALSAM OF STORAX. 497 
 
 turbidity with | of its weight of fixed oil, or with | of its weight of balsam of copaiba ; 
 but if a larger quantity of either of these liquids be added, two layers are formed. 
 Sulphuric acid converts it into a thick red mass, with evolution of sulphurous acid ; 
 nitric acid acts upon it only when heated, giving off nitrous fumes and hydrocyanic 
 acid ; after the evaporation of the mixture, there remains a brownish-yellow bitter 
 substance, soluble in water. When 2 volumes of the balsam are gently heated with 
 
 3 volumes of potash-ley, of specific gravity 1-3, two layers of liquid are formed, the 
 upper consisting of a brownish oil (oil of Peru balsam), and the lower, which is watery, 
 containing cinnamic acid, resins, and colouring matters in combination with potash. 
 
 4 pts. of the balsam form a soapy mixture with 1 pt. hydrate of potassium aW 1 pt. of 
 water. When subjected to dry distillation, it begins to boil at 287 C. and yields, 
 with continual rise of temperature, an oil coloured byproducts of decomposition, while 
 a porous charcoal remains in the retort. 
 
 Black Peru balsam has been repeatedly analysed. The earliest examination of it 
 was made in 1824, by Stoltze (Berliner. Jahrb. f. Pharm. xxv. 24), who found in 
 100 pts. 69-0 pts. of a peculiar volatile oil, 6*4 of acid (supposed at the time to be 
 benzoic acid, but really consisting of cinnamic acid), 20*7 resin easily soluble in 
 alcohol, 2'4 resin sparingly soluble in alcohol, 0'6 extractive matter, and 0*9 moisture. 
 
 According to Fremy (Ann. Ch. Phys. [2] Ixx. 180), the balsam is composed of 
 variable quantities of a volatile oil (cinnamein or styracin), a crystallisable substance 
 {metacinnamein}, isomeric therewith, cinnamic acid, and resin. On dissolving the 
 balsam in alcohol, and adding alcoholic potash, the resin is precipitated in combination 
 with potash, while the cinnamein remains dissolved, and may be precipitated by 
 water, the cinnamic acid still remaining in solution. The oil is purified from resin by 
 solution in rock-oil and evaporation ; by exposing it to a low temperature, and redis- 
 solving in weak alcohol, the crystalline metacinnamein, which however is not always 
 present, is separated (see CINNAMEIN). The resinous portion of the balsam appears to 
 be a mixture of several distinct resins, one of which agrees in composition with the 
 resin produced from cinnamein by the action of sulphuric acid ; another differs from 
 that just mentioned merely by containing a smaller amount of the elements of water. 
 Fremy therefore regards cinnamein and metacinnamein as the original constituents 
 of Peru balsam, the cinnamic acid as a product of oxidation, and the resins as hydrates 
 of cinnamein. This view explains the variation in constitution of the balsam with 
 age ; also the fact that cinnamic acid is still present in the balsam after it has been 
 boiled with water, and increases in quantity with the age of the balsam. 
 
 For Plantamour's results, which agree with those of Fremy, so far as regards the 
 presence of cinnamein and cinnamic acid, see Ann. Ch. Pharm. xxvii. 329 ; xxx. 347. 
 According to Scharling (ibid, xcvii. 168), the cinnamein obtained from different 
 samples of Peru balsam is not of constant composition ; but the formulae which he 
 assigns to them are improbable. 
 
 The resin of Peru balsam mixed with pumice and subjected to dry distillation, yields 
 benzoic acid, together with an oily and a watery distillate. On distilling the former 
 by itself, a lighter oil passes over at 175 C., and afterwards a heavy liquid, which 
 sinks to the bottom. The light oil, repeatedly rectified with potash-ley, and finally 
 over hydrate of potassium, yields pure cinnamene, C 8 H 8 . The heavier liquid appears to 
 consist of benzoate of methyl and phenic acid : when distilled with potash-ley, it yields 
 wood-spirit. (Scharling, loc. tit.) 
 
 Black Peru balsam is used in medicine as an application to wounds, and also as an 
 internal remedy. It is also used in perfumery, and in the preparation of chocolate, as 
 a substitute for vanilla. The white and dry balsams (p. 496) are scarce, and have 
 not received any practical application. 
 
 Adulterations in Peru balsam may be detected as follows : Fixed oils remain un- 
 dissolved on treating the balsam with strong alcohol ; volatile oils lower the boiling 
 point, and pass over on distilling the balsam with water; copaiba balsam and tur- 
 pentine may be recognised by the odour which they give out when heated ; also by 
 yielding volatile oils on distillation with water ; sugar and all substances soluble in 
 water, by the diminution of volume which the balsam so adulterated undergoes when 
 shaken up with water ; syrup of sugar also renders the balsam turbid. 
 
 STORAX BALSAM. This balsam is _ the produce of Styrax officinalis, a shrub 
 growing in the Levant, Palestine, Syria, and Greece. It is imported into Europe 
 from Trieste. There are two principal varieties of it, Styrax liquidus, and Styrax 
 calamita. 
 
 a. Liquid storax. This variety is sometimes transparent, of brownish-yellow colour, 
 of the consistence and tenacity of Venice turpentine, and has a peculiar sweetish or 
 vanilla- like odour; sometimes opaque, with grey colour, the consistence of bird-lime, 
 and a strong oppressive odour, slightly mixed with that of benzene or naphthalene. 
 1 iquid storax is a mixture of styrol, cinnamic acid, stvracin, and resins. 
 
 VOL. I. K K 
 
498 BALSAM OF TOLU. 
 
 b. Heed storax, Styrax calamita. This is imported in compact masses of fragrant 
 odour and rich brown colour, interspersed with white tears, whence it has also been 
 called amygdaloid storax. According to Keinsch, it contains about 0'5 per cent of 
 volatile oil, 33 to 54 per cent, resin, 1-1 to 2 P 6 benzoic acid, 8 to 14 gum and extract, 
 9*6 to 24 matter extracted by potash, 20 to 27 woody fibre, 5 water, and traces of 
 ammonia. The drug sold under this name is, however, of very variable composition, 
 often consisting of nothing but saw-dust or decayed wood, impregnated with coal- 
 tar, or some similar substance, and bearing no resemblance whatever to the genuine 
 storax. 
 
 Storax is used in medicine, as a stimulating expectorant, its operation being 
 analogous to that of Peru balsam or benzoin. It is also used as a detergent, in the 
 form of ointment. (Muspratt's Chemistry, i. 225.) 
 
 TOLU BALSAM. This balsam is obtained in large quantity from incisions in the 
 stem of the Myrospermum toluiferum (Sprengel), Myroxylum toluiferum (Eichards), 
 a tree growing in various districts of Columbia, viz. in the mountains of Turbaco 
 and Tolu, and on the Magdalena River. In the fresh state it is yellowish, trans- 
 parent and liquid, like turpentine (white tolu-balsam} but changes rather quickly by 
 keeping, acquiring a reddish-brown colour and stiff consistence (black tolu-balsam'}, and 
 being ultimately converted into a friable substance of granular crystalline structure 
 (dry tolu-balsam). It has an aromatic odour, like that of lemon and jasmine, and a 
 sweetish, aromatic, somewhat irritating taste. It melts at a gentle heat ; dissolves 
 readily and completely in alcohol ; less readily in ether and in volatile oils ; not com- 
 pletely in fixed oils. Hot water extracts from it cinnamic acid (and, according to 
 Deville and Scharling. likewise benzoic acid), together with volatile oil. Heated with 
 strong sulphuric acid, it forms a red solution without giving off sulphurous acid. With 
 potash-ley of specific gravity T17, it forms a clear solution having an odour of violets, 
 and with drops of oil floating on the surface. 
 
 Tolu balsam is a mixture of volatile oil, free acid, and resin. The volatile oil is ob- 
 tained by distilling the balsam with water, the quantity being always small, but 
 varying according to the age of the balsam. Deville obtained 0-2 per cent., Scharling 
 1 per cent., and, by afterwards passing steam heated to 170C. through the balsam, 
 0-2 per cent. more. This oil is, according to Deville, a mixture of tolene, C 12 H 18 , pass- 
 ing over betweeen 160 and 170 C., and cinnamein, C 16 H M 2 , which distils between 
 340 and 350 C. According to E. Kopp and Scharling, on the other hand, the oil 
 consists wholly of tolene, which, according to Kopp, is isomeric witli oil of turpentine, 
 C 10 H 16 . The small quantity of volatile oil contained in Tolu balsam, and the rapidity 
 with which it hardens by exposure to the air, are characters by which it is readily 
 distinguished from balsam of Peru. 
 
 The free acid of Tolu balsam consists, according to Deville and Scharling, of cin- 
 namic and benzoic acids ; according to Fremy and E. Kopp, of cinnamic acid only. 
 The balsam boiled with water, yields a solution which, on cooling, deposits crystals 
 chiefly of cinnamic acid (Deville). The oil obtained by distilling the balsam with 
 water, and cohobating the distillate several times, deposits benzoic acid when exposed 
 to the air (Deville). Benzoic acid is likewise extracted, together with cinnamic acid, 
 by treating the balsam with aqueous carbonate of sodium, or caustic potash, adding 
 chloride of calcium to precipitate the resins, and supersaturating the filtrate with hy- 
 drochloric acid (Deville, Scharling). E. Kopp is of opinion that the benzoic acid 
 is a product of decomposition, and does not pre-exist in the balsam. 
 
 Eesins. According to E. Kopp, Tolu balsam contains two resins, an resin, easily 
 soluble in alcohol, and a /3 resin, C 18 H 20 5 , sparingly soluble in alcohol. 
 
 The a resin, C 18 H 19 4 , according to Kopp, but more probably C 18 H 18 4 , as suggested 
 by G-erhardt (Traite, iii. 408), is obtained by treating the balsam with cold alcohol, 
 after it has been freed from volatile oil and cinnamic acid by distillation and boiling 
 with water. It is brown, translucent, and shining ; friable in the cold ; but the 
 powder cakes together even at + 15 C., and the resin melts at 60 C. Strong sul- 
 phuric acid colours it purple-red. When dissolved in potash-ley, and exposed to the 
 air, it oxidises readily, and is converted into )8 resin. By dry distillation it yields 
 toluene and benzoic acid. 
 
 The )8 resin, C 18 H*0 5 , is brownish, dull, and without taste or smell ; melts at a 
 temperature above 100 C. It is sparingly soluble in alcohol and ether, dissolves with 
 brown colour in potash- ley, and is precipitated with violet colour by sulphuric acid. 
 It is more permanent than the a resin. 
 
 The mixture of the two resins, treated with nitric acid, yields a number of volatile 
 and gaseous products, consisting of carbonic anhydride, nitrous anhydride, nitric oxide, 
 bitter-almond oil, hydrocyanic acid, and a small quantity of benzoic acid, and there 
 remains a yellow mass, consisting of benzoic acid and a yellow resinous colouring 
 matter, which prevents the benzoic acid from crystallising till it has been separated by 
 
BALSAMS BAMLITE. 499 
 
 sublimation. The resin thus treated yields about a third of its weight of pure benzoic 
 acid. 
 
 According to Deville, Tolu balsam contains only one kind of resin, which has the 
 composition of the resin just described. To extract it, Deville dissolves the balsam 
 in potash largely diluted with water, saturates the liquid with carbonic acid gas, 
 whereby a small quantity of resin is precipitated, then adds chloride of calcium, which 
 precipitates the carbonic acid and the rest of the resin as calcium-salts, leaving benzoic 
 and cinnamic acids in solution. The rose-coloured mass, left after filtration, is then 
 treated with hydrochloric acid, which dissolves out the lime and leaves the resin, and 
 the latter is purified by solution in a small quantity of alcohol and precipitation by 
 water. It then forms a rose-coloured powder, having a faint odour of vanilla, soluble 
 in alcohol and in potash, very hygrometric, and varying considerably in colour from 
 the effect of atmospheric influences, and perhaps also of light. Treated with fuming 
 nitric acid, it takes fire and burns as in oxygen. By dry distillation, it yields a small 
 quantity of water, benzoic acid, toluol, benzoate of ethyl, and a mixture of carbonic 
 oxide and carbonic anhydride. (Deville.) 
 
 Scharling finds that, when the resins of Tolu balsam are mixed with half their 
 weight of .powdered pumice, and covered in" the retort with a layer of pumice, the 
 process of dry distillation goes on quietly and without tumefaction. 16 pts. of the 
 resin heated in this manner, ultimately to redness, yield 2 pts. of a watery, and 5 pts. 
 of an oily liquid, which is heavier than water, and is resolved by fractional distillation 
 into toluol, phenic acid, and a portion boiling above 198 C. The latter was not ob- 
 tained of constant boiling point, and yielded by analysis numbers intermediate 
 between the composition of benzoate of ethyl, C 7 H 3 (C 2 H 5 )0 2 , and benzoate of methyl. 
 C 7 JI 5 (CH 3 )0 2 . When distilled with potash, however, it yielded only methylic alcohol, 
 without any common alcohol; hence it appears that the products of distillation of the 
 resins are toluene, phenic acid, and benzoate of methyl. 
 
 The mode of formation of Tolu balsam is not known with certainty. If we regard 
 cinriamein as the primary constituent, the resins a and may be formed from it by 
 absorption of oxygen and water : 
 
 C 18 H 18 4 = C 18 H 16 2 + + H 2 
 resin. Cinnamein. 
 
 C 18 H 20 5 = C 18 H 16 2 + + 2H 2 
 
 P resin. 
 
 or the a resin may be converted by oxidation into the j3 resin and cinnamic acid : 
 2C 18 H 18 4 + = C 18 H 2e 5 + 2C 9 H 8 2 
 
 resin. resin. Cinuamic 
 
 acid. 
 
 Lastly, the )8 resin may split up into benzoic acid, water, and a hydrocarbon : 
 C 18 H 80 0* = 2C 7 H 6 2 + H 2 + C 4 H 6 
 
 which hydrocarbon is supposed by E. Kopp to give rise to the formation of tolene. 
 Scharling, on the other hand, supposes that all the constituents of the balsam are 
 formed from tolene, inasmuch as this body, when exposed to the air, quickly becomes 
 resinous and acquires an acid reaction. It must be observed, however, that the resins 
 thus formed are very different in composition and properties from those of Tolu balsam, 
 and the nature of the acid has not been determined. 
 
 Tolu balsam is used medicinally to facilitate expectoration in coughs and chronic 
 catarrhs ; also in perfumery. It is said to be often adulterated with liquid storax, 
 liquidambar, and Canada balsam. Pure Tolu balsam may be known by its perfect 
 transparency when fresh ; by its odour ; by its freedom from water ; by its perfect solu- 
 bility in potash-ley of T17, and in alcohol ; and by its reaction with sulphuric acid. 
 
 B All SAM 5, ARTIFICIAL Pharmaceutical preparations, chiefly for external 
 use, and somewhat resembling the natural balsams in their physical character, 
 e. g. Balsamum opodeldoc, an alcoholic soap-solution containing ammonia ; Balsamum 
 Arcai, a salve containing elemi-resin ; Balsamum sulphuris, a solution of sulphur in 
 linseed oil, &c. 
 
 BAXiTIMORITE. A variety of chrysotil, or fibrous serpentine, found at Balti- 
 more in North America. 
 
 BAIVZIiITE. A silicate of aluminium, found in microscopic linear or fibrous 
 crystals, at Bamle in Norway. Specific gravity 2'984 ; hardness about equal to that 
 of disthene ; colour varying from white to pale greenish ; lustre vitreous to silky ; 
 translucent, or in single individuals nearly transparent and colourless. According to 
 Erdmann' s analysis (J. pr. Chem. xxxi. 165) it contains 56'9 silica, 4( i>7 3 alumina, 
 
 K K 2 
 
500 BARALITE BARIUM. 
 
 1-04 ferric oxide, 1'04 lime, and traces of fluorine, numbers which correspond nearly 
 to the formula Si 9 Al 16 30 = 4Al 4 3 .9Si0 2 ; but it requires further examination. 
 Kobell regards it as a mixture of disthene and quartz. 
 
 BARAXiXTX! or BAVAXiITE. A mineral from Baralon, Cote du Nord, con- 
 taining silica, alumina, ferric oxide, lime, magnesia, and water. It is probably a 
 mixture, the separate constituents of which are not distinguishable by the eye. 
 
 BARBATIIVXAO. A name applied to several Brazilian barks containing tannin, 
 and used both as astringent medicines and in the tanning of leather. 
 
 BARDXGXiXONX:. A blue variety of anhydrite cut and polished for various 
 ornamental purposes. 
 
 BAREaXN. Glairin. A nitrogenous substance contained in sulphurous thermal 
 springs, especially in France. It forms a deposit on the sides of the basins and 
 conduits of the springs, which are sometimes filled with water and sometimes empty, 
 never occurring in parts which are constantly full. The name baregin is derived from 
 its occurrence at Bareges; it is also called Plombierin, from Plombi6res, another 
 locality in which it is found in considerable quantity. Baregin is in the moist state 
 a transparent, gelatinous, nearly colourless substance, destitute of taste and odour. 
 It dissolves very sparingly in the cold, more readily at higher temperatures, in water, 
 alcohol, aqueous acids, and alkalis, and in oil of turpentine ; insoluble in ether. 
 "When dried, it forms a horny mass, and on heating this mass, it emits an odour like 
 that of burnt horn, together with ammoniacal vapours. According to Bouis (Compt. 
 rend. xli. 16) it contains from 44 to 487 per cent, of carbon, 67 to 77 hydrogen, 
 5'6 to 8'1 nitrogen, and 30'2 to 407 per cent, of ash, chiefly consisting of silica. It 
 does not contain sulphur. According to Danberg, it consists for the most part of a 
 mass of confervse and oscillatorise. 
 
 Nearly allied to, if not identical with baregin, is a substance which is sometimes 
 formed in the quick method of preparing vinegar (see ACETIC Aero, p. 7), and attaches 
 itself in gelatinous shreds to the inside of the perforated casks. This substance when 
 dried forms a parchment-like layer, containing 42 per cent, carbon and 6 hydrogen, 
 besides nitrogen and oxygen, and leaving an alkaline ash. (Grerh. iv. 536 ; Handw. 
 d. Chem. 2 te Aufl. ii. 643.) 
 
 BARXXiXiA or BARXXiXiOR. The term given in commerce to the impure soda 
 imported from Spain and the Levant. It is made by burning to ashes different plants 
 that grow on the sea shore, chiefly of the genus Sal sola, and is imported in hard 
 porous masses of a speckled brown colour. Kelp, a still more impure alkali, made in 
 this country by burning various sea- weeds, is sometimes called British barilla. These 
 substances were formerly the source of all the soda of commerce ; but their use is 
 now almost entirely superseded by the manufacture of soda from common salt. 
 
 BARXUXVX. Symbol Ba; Atomic weight 68'5. (The name is derived from fiapvs, 
 heavy, in allusion to the great density of its compounds.) This metal occurs abun- 
 dantly as a sulphate and carbonate ; also in the mineral barytocalcite, a carbonate of 
 barium and calcium, in certain ores of manganese, in Harmotome and in Brewsterite; 
 traces of it has also been found in mineral waters. It is never found native. The 
 oxide, baryta, was first recognised as a peculiar earth, distinct from lime, by Scheele, 
 in 1774 ; and the metal itself was first obtained by Davy, in 1808. 
 
 Preparation. 1. Hydrate of barium, or the carbonate, chloride, or nitrate, is made 
 into a doughy mass with water, formed into a cup, and placed upon a platinum dish, 
 which is connected with the positive pole of a voltaic battery of 500 pairs of plates, 
 the cup being filled with mercury, into which the negative wire dips. The amalgam 
 of barium thus obtained is heated in a tube of glass without lead, filled with the 
 vapour of rock-oil, till all the mercury is sublimed (Sir H. Davy). If the hydrate of 
 barium is mixed with oxide of mercury, the amalgam is obtained in larger quantity 
 (Sir H. Davy.) Hare (J. pr. Chem. xix. 249) prepared the amalgam in a similar 
 manner from moistened chloride of barium surrounded by a freezing mixture, using 
 two batteries, each of 100 pairs, and containing more than 100 square feet of zinc. 
 The mercury was expelled by heating the amalgam in an iron^ crucible provided with 
 an iron cover, and exhausted of air. 2. Barium may be obtained in an impure state, 
 according to Davy, by passing vapour of potassium over red-hot baryta or chloride of 
 barium. 3. Pure baryta or the nitrate is placed in a hole made in a piece of charcoal 
 or slate, and exposed to a burning jet of detonating gas, produced from three measures 
 of hydrogen and one measure of oxygen gas. Effervescence takes place, and white, 
 shining little globules of metallic barium are formed. The baryta must be anhydrous 
 and the detonating gas must be passed through oil and not through water; otherwise a 
 translucent vitreous or horny mass will be obtained. (Clarke, Ann. Phil. xvii. 419.) 
 4. Buns en subjects chloride of barium, mixed up to a paste with water and a little 
 
BARIUM: CHLORIDE. 501 
 
 hydrochloric acid, at a temperature of 100 C., to the action of the electric current, 
 using an amalgamated platinum wire as the negative pole. In this manner, the metal 
 is obtained as a solid, silver- white highly crystalline amalgam, which, when placed in a 
 little boat made of thoroughly ignited charcoal, and heated in a stream of hydrogen, 
 yields barium in the form of a tumefied mass, tarnished on the surface, but often 
 exhibiting a silver-white lustre in the cavities (Pogg. Ann. xci. 619). Matthiessen 
 has obtained barium by a method similar to that adopted for strontium (q. v.} ; but 
 only in the form of a metallic powder. 
 
 Properties. Barium, according to Davy, is a silver-white metal with less lustre than 
 cast-iron ; according to Clarke, it has the colour and lustre of iron ; according to 
 Matthiessen, it is a yellow powder. It sinks rapidly in strong sulphuric acid, even 
 when surrounded by bubbles of gas. Its specific gravity, according to Clarke, is 4-0 
 or somewhat greater. It is ductile, and may be beaten flat, though with difficulty. 
 It melts below redness, and does not volatilise at a red heat. It oxidises rapidly in 
 the air, becoming heated at the same time, and decomposes water rapidly at ordinary 
 temperatures. When heated in the air, it burns with a dark red light (Davy) ; before 
 the oxy-hydrogen blowpipe it burns with a greenish flame (Clarke). Sulphuric 
 acid rapidly converts it into sulphate, with evolution of hydrogen. 
 
 BARIU1VI, BROZKXDS OF. BaBr. Crystallised: BaBr.H 2 0. Prepared by 
 saturating baryta- water, or sulphide, or carbonate of barium with hydrobromic acid, 
 or by decomposing the sulphide with free bromine, sulphur being at the same time 
 precipitated. It is very soluble in water and crystallises with difficulty. Isomor- 
 phous with the chloride. It is soluble in strong alcohol, and may thus be separated 
 from the chloride, which is nearly insoluble in that liquid. 
 
 BARIUM, CHLORIDE OP. BaCl. Crystallised, BaCl.H 2 0. The hydrated 
 Bait was formerly called Terra ponderosa salita. This salt is prepared either from the 
 carbonate or from the sulphate of barium, both of which are natural minerals. The 
 carbonate (witherite) is simply dissolved in hydrochloric acid, and the resulting chlo- 
 ride purified by recrystillation. From the native sulphate (heavy spar), the chloride 
 may be prepared in two ways : 1. By igniting the sulphate in a crucible with pounded 
 coal, whereby it is converted into sulphide, Ba 2 S, extracting the sulphide by boiling 
 water, and decomposing the filtered solution with hydrochloric acid : 
 
 Ba 2 S + 2HC1 = 2BaCl + H 2 S; 
 
 The acid is added in sufficient quantity to produce a strong acid reaction, and the liquid 
 is boiled for some time to drive off all the sulphuretted hydrogen, then filtered, eva- 
 porated, and cooled till it crystallises. 2. By heating a mixture of 2 pts. heavy spar, 
 and I pt. fused chloride of calcium to redness for about an hour. Sulphate of calcium and 
 chloride of barium are then formed (SO 4 Ba 2 + 2CaCl = S0 2 Ca 2 + 2BaCl), and the 
 latter may be extracted by pulverising the fused mass, boiling with water, and filter- 
 ing as quickly as possible ; otherwise, a portion of the chloride of barium will be re- 
 converted into sulphate, because the sulphate of calcium in the residue gradually 
 dissolves in the water, and mixing with the dissolved chloride of barium, produces a 
 reaction exactly the reverse of that which took place in the fused mass. The decom- 
 position of the sulphate may be facilitated by adding to the mixture in the crucible a 
 quantity of iron filings and charcoal. Sulphide of iron is then formed, together with 
 an insoluble oxysulphide of calcium, from which the chloride of barium may be sepa- 
 rated by water as above. 
 
 Commercial chloride of barium often contains small quantities of the chlorides of 
 strontium and calcium ; also chloride of aluminium, sesquichloride of iron, and some- 
 times traces of copper and lead. The chlorides of strontium and calcium may be 
 removed by washing the crystals with alcohol ; the latter also by digesting the aqueous 
 solution with carbonate of barium, whereby the chloride of calcium is slowly decom- 
 posed and converted into carbonate ; the same decomposition may be more quickly 
 effected by adding baryta-water, and then passing carbonic acid gas into the liquid. 
 Digestion with carbonate of barium also precipitates the aluminium and iron in the 
 form of sesquioxides. Lead and copper may be precipitated by adding to the solution 
 a small quantity of sulphide of barium. 
 
 Chloride of barium crystallises from its aqueous solution in transparent, colourless, 
 four-sided tables, belonging to the trimetric or right prismatic system. The form of 
 the crystals resembles that of heavy spar. The angles are oo P : o> P = 93 20' 
 oP : P oo = 142 35'; oP : P oo = 140 57'. The crystals decrepitate in the fire! 
 Their specific gravity is 2'66 (Filhol) ; cubical expansion from to 100 C. = 0-00987 
 (Joule and PI ay fair). They^have an unpleasant, bitter, and sharply saline taste, 
 excite nausea, and afe highly poisonous. 
 
 100 pts. of water at C. dissolve 32-62 pts. of anhydrous chloride of barium and 
 
 KK 3 
 
502 BARIUM: DETECTION. 
 
 0-2711 pts. for every degree above C. ; 100 pts. of water at 15*6 dissolve 43'5, and at 
 105-5, 78 pts. of the crystallised chloride (Gray-Lussac). One pt. of crystallised 
 chloride of barium dissolves at 18'1 in 2'257 pts. of water, forming a solution of 
 specific gravity 1-28251 (Karsten). Specific gravity of a saturated solution at 
 8 = 1-270 (Anthon). Water acidulated with hydrochloric acid dissolves less than 
 pure water, and concentrated aqueous hydrochloric acid hardly any ; so that a satu- 
 rated solution in water is precipitated by it. Hot absolute alcohol dissolves only 
 ~ pt. of the crystals, but more if it contains water. According to Fresenius 
 (Ann. Ch. Pharm. lix. 117), one pt. of the salt dissolves in 8108 pts. of alcohol of 
 99-3 per cent, at 14 C., and in 4857 pts. of the same alcohol at the boiling heat. 
 
 The crystals do not effloresce in the air: at 100 C. they give off the whole of their 
 water, leaving the anhydrous chloride in the form of a white mass, which melts at a 
 full red heat, and is translucent after solidification. Specific gravity of the anhydrous 
 chloride = 3-7037 (Karsten), 3-8 (Richter), 3-86 to 4-156 (Pol. Boullay). Heated 
 by itself, it does not become alkaline till after fusion ; but when heated in aqueous 
 vapour, it becomes alkaline below the melting point, and evolves hydrochloric acid. 
 By ignition with sulphur it is partly changed into sulphide of barium (Karsten). 
 It is not decomposed, at ordinary temperatures, by vapour of anhydrous sulphuric acid. 
 According to H. Wurtz, it completely decomposes silicates when fused with them. 
 
 Chloride of barium in the state of concentrated solution, is decomposed by nitrate 
 of potassium or sodium, yielding nitrate of barium and a chloride of the alkali-metal, 
 It forms a crystalline compound with glycocol. Blood mixed with it remains fluid 
 and does not putrefy. 
 
 The chief use of chloride of barium is as a chemical reagent, especially for the 
 detection and estimation of sulphuric acid. 
 
 BARIUM, CYANIDE OF. See CYANIDES. 
 
 BARIUM, DETECTION AND ESTIMATION OF. 1. Reactions in 
 the dry way. Barium-compounds, heated in the inner blowpipe flame, colour the 
 outer flame green. They likewise impart a green colour to the flame of alcohol, and 
 when this flame is examined with a prism by Bunsen and KirchhofFs method (see 
 ANALYSIS, INOEGANIC, p. 214, and LIGHT), a spectrum is seen, having several broad 
 green bands, in the neighbourhood of Fraunhofer's lines b, E, a bright yellow band 
 coincident with the line D, a bright orange band just beyond it, and two fainter 
 orange-red bands, one of which nearly coincides with the line C. 
 
 Beactions in the wet way. The hydrate, sulphide, chloride, nitrate, and many 
 organic salts of barium, the acetate, for example, are soluble in water ; most of the 
 other salts are insoluble in water, but soluble in nitric and hydrochloric acid : the 
 sulphate and the silicofluoride are insoluble in all acids. All barium-compounds are 
 colourless, excepting those which, like the chromate, contain a coloured acid. The 
 soluble salts of barium are poisonous. Solution of potash (free from carbonate), forms 
 a precipitate of hydrate of barium, only in very concentrated solutions of barium-salts : 
 ammonia forms no precipitate, even in the most concentrated solutions. Alkaline car- 
 bonates form a white precipitate of carbonate of barium, soluble, with efflorescence, in 
 hydrochloric acid. Phosphate, arsena-te, borate, and iodate of sodium, also form precipi- 
 tates soluble in acids. Free oxalic acid, or acid oxalate of potassium, precipitates 
 oxalate of barium, only from very concentrated solutions ; neutral alkaline oxalates 
 form a precipitate in all neutral solutions of barium-salts, which are not very dilute. 
 Neutral alkaline succinates precipitate barium-salts quickly or slowly, according to 
 the concentration of the solutions. Ferrocyanide of potassium forms a precipitate in 
 moderately dilute solutions ; ferricyanide only in strong solutions. Sulphydric acid, 
 sul,phide of ammonium, and perchloric acid, form no precipitates. Sulphuric acid and 
 soluble sulphates, throw down sulphate of barium, from all solutions of barium-salts, 
 whether neutral or acid. The precipitate is insoluble in nitric or hydrochloric acid, 
 even at the boiling heat. A solution of nitrate of barium, containing only 1 pt. 
 of baryta in 50,000 to 100,000 pts. of water, gives a very distinct cloudiness with 
 sulphuric acid or sulphate of sodium; with 200,000 to 400,000 pts. of water, after 
 some minutes only ; and with 800,000 pts, of water, the reaction is no longer visible. 
 (Lassaigne, J. Chim. me"d. viii. 526.) According to Harting (J. pr. Chem. xxii. 
 58), a solution of chloride of barium containing 1 pt. of baryta in 71,000 pts. of water, 
 becomes turbid with sulphate of sodium after the lapse of half an hour. Alkaline 
 chromates form with barium-salts, a yellowish precipitate of chromate of barium, in- 
 soluble in dilute acids, soluble only in a large excess of nitric acid. Hydrofluosilicic 
 acid forms with barium-salts, after a while, a white crystalline precipitate, nearly in- 
 soluble in nitric or hydrochloric acid. This reaction will detect 1 pt. of the chloride 
 in 3800 pts. of water. The precipitation is accelerated by addition of alcohol. 
 
 This last reaction affords a complete distinction between barium and strontium ; 
 
BARIUM: ESTIMATION. 503 
 
 the latter metal not being precipitated by hydrofluosilicic acid. The reaction with 
 sulphuric acid distinguishes barium in solution from all other metals, except lead and 
 strontium. From lead it is easily distinguished by its behaviour with sulphuretted 
 hydrogen, which forms a black precipitate with lead, and by many other characters. 
 Strontium and calcium are distinguished from barium by the greater solubility of their 
 sulphates, so that a solution of sulphate of strontium, or calcium, added to a soluble 
 barium-salt, forms a precipitate of sulphate of barium. Another distinction is afforded 
 by the colour imparted to the flame of alcohol by the compounds of these two metals, 
 barium-compounds colouring the flame pale green (p. 500), while strontium compounds 
 colour it deep red. The tabular crystals of chloride of barium, which are nearly in- 
 soluble in alcohol, likewise afford a means of distinguishing barium from strontium 
 and calcium, the chlorides of which form hygroscopic needle-shaped crystals, easily 
 soluble in alcohol. 
 
 3. Quantitative Estimation. Barium is always estimated in the form of 
 sulphate. The precipitation is effected by means of dilute sulphuric acid. The acid 
 must be added in excess, and to a hot solution of the barium-salt ; otherwise a small 
 quantity of the original salt, especially if it be nitrate, will be thrown down undecom- 
 posed together with the sulphate. The precipitate is washed with hot water, ignited 
 at a moderate heat, together with the filter, and the amount of barium or of baryta 
 calculated from its weight. 100 pts. of it correspond to 5878 pts. of barium, and 
 65-64 of baryta. 
 
 This mode of estimating barium is very exact ; but the precipitate, unless certain 
 precautions are taken, is very troublesome to filter, sometimes passing through as a 
 milky liquid, and sometimes completely stopping up the pores of the paper. To avoid 
 these inconveniencies, the liquid must be heated, and the precipitate allowed to settle 
 down completely, before the filtration is commenced. The clear liquid is then to be 
 passed through the filter, the precipitate stirred up with boiling water, and again left 
 to settle down, this clear liquid also poured through the filter, and the same process 
 repeated three or four times. The result of this treatment is to render the precipitate 
 dense and granular ; it may then be poured on the filter, and washed with hot water 
 as above-mentioned. 
 
 Kecent experiments have shown that sulphate of barium is soluble to a perceptible 
 extent in strong hydrochloric, and still more in nitric acid (Calvert, Chem. Gaz. 
 1856, 55. Nicholson and Price, Phil. Mag. [4] xi. 169. Noad, Chem. Soc. Qu. 
 J. ix. 25). According to Seigle (J. pr. Chem. Ixix. 144), it is also slightly soluble 
 in dilute acids, but less in acetic than in hydrochloric or nitric acid. Care must 
 therefore be taken that the liquid, from which the sulphate of barium is precipitated, 
 does not contain too much free acid ; and it must be washed with pure, not with 
 acidulated water. 
 
 Barium ^ may also be estimated as carbonate ; but the method is less accurate 
 than that just described, because carbonate of barium is not completely insoluble in 
 water. 
 
 4. Atomic Weight of Barium. The most exact estimations of this number have 
 been made by determining the amount of chloride of silver obtained by precipitating 
 pure chloride of barium with nitrate of silver. In this manner Marignac (Ann. 
 Chem. Pharm. Ixviii. 215), operating on chloride of barium purified by washing with 
 alcohol, recrystallisation from water, and drying at a low red heat, found, as a mean 
 of six closely agreeing experiments, that 1 pt. of silver corresponds to 0'96365 pt. of 
 BaCl. Hence, the atomic weight of silver being 108, we have : 
 
 Atomic weight of BaCl = 0-96365 x 108 = 104-07 
 Whence deducting . Cl . . = 35-50 
 
 There remains . . Ba . . = 68-57 
 
 In like manner, the atomic weight of barium was estimated byBerzelius (Schw. J. 
 xx. 1014) at 68-40, and by Pelouze (Compt rend. xx. 1047) at 68-65. 
 
 Lastly, Dumas (Ann. Ch. Phys. [3] Iv. 129), by numerous experiments made with 
 chloride of barium, carefully purified and fused in a stream of hydrochloric acid gas, 
 has obtained results varying between the limits 68'47 and 68-56 ; mean value = 68'5, 
 which last number is here adopted. 
 
 The atomic weight of barium has likewise been estimated from the amount of 
 sulphate produced from a given weight of chloride ; but the results do not appear to 
 be so trustworthy as those obtained by the method above described. 
 
 5. Separation of Barium from other metals. The precipitation of barium 
 by sulphuric acid affords the means of separating it from all other elements excepting 
 strontium, calcium and lead. From strontium and calcium it may be separated by 
 hydrofluosilicic acid, which throws down a crystalline precipitate of silicofluoride of 
 
 KX 4 
 
504 BARIUM: IODIDE OXIDE. 
 
 barium 2BaF.SiF 2 . This precipitate is somewhat soluble in water, but the separation 
 may be rendered complete by adding alcohol and warming the liquid : from dilute 
 solutions it takes some time to settle down. It must be collected on a weighed filter, 
 dried at a moderate heat, and weighed. 100 pts. of it correspond to 49*01 of barium 
 and 54 '73 of baryta. For other methods of separation, see CALCIUM and STBONTIUM. 
 
 The separation of lead from barium is easily effected by sulphydric acid, which pre- 
 cipitates the lead as sulphide. 
 
 BA.RXU1VX, FLUORIDE OP. BaF. Obtained by neutralising baryta-water 
 with hydrofluoric acid, by digesting the recently precipitated carbonate in that acid, or 
 by decomposing nitrate of barium with fluoride of potassium or sodium. It is a white 
 powder, or, when obtained by evaporating the acid solution, a granular crystalline 
 crust. It is insoluble in water, but dissolves easily in nitric, hydrochloric, or hydro- 
 fluoric acid. 
 
 Fluoride of barium unites with the fluorides of boron and silicon, forming the com- 
 pounds BaF.BF 3 and 2BaF.SiF 2 . The latter is nearly insoluble in water, and serves 
 for the separation of barium from strontium and calcium, p. 502 (see BoROFLUOBiDEa 
 and SELICOFLUORIDES). It also forms a crystalline compound with chloride of barium, 
 BaCLBaF, which is produced on mixing a solution of fluoride of potassium or fluoride 
 of sodium with chloride of barium. This compound is more soluble than the fluoride 
 itself, and remains as a granular mass when the solution is evaporated. 
 
 BARIUM , IODIDE OP. Bal. Formed when hydriodic acid gas is passed 
 over baryta at a red heat, the combination being attended with production of light. 
 Protosulphide of barium dissolved in water is mixed with a saturated alcoholic 
 solution of iodine [iodine without the alcohol might be preferable], as long as a pre- 
 cipitate of sulphur is formed; the colourless filtrate is boiled rapidly so as to prevent 
 the action of the air almost to dryness; the mass is dissolved in a small quantity of 
 water, and filtered quickly ; and the filtrate is evaporated to dryness in as short a 
 space of time as possible in a glass bolt-head. (0. Henry.) 
 
 On redissolving the mass in hot water and leaving the solution to cool, the hydrated 
 salt crystallises in slender deliquescent needles containing, according to Croft (Chem. 
 Gaz. 1856, p. 125), 2BaI.7H 2 ; they dissolve readily in alcohol. Heated out of 
 contact with the air, they leave the anhydrous salt, which is not decomposed by heat 
 in a close vessel, but in contact with the air, decomposes slowly at ordinary tempera- 
 tures and quickly when heated, giving off vapours of iodine and leaving baryta. 
 
 BARIUM, OXIDES OP. Barium forms two oxides, a protoxide, Ba 2 0, and a 
 dioxide or peroxide, BaO ; the first produced by the direct oxidation of the metal, or 
 by heating certain of its salts ; the second, by heating the protoxide to dull redness in 
 contact with excess of oxygen. 
 
 PROTOXIDE OF BARIUM, or BARYTA, Ba 2 0, or BaO. Barytes, Terra ponderosa, 
 Terre pesante, Schwererde. Barium oxidises rapidly in the air, even at ordinary 
 temperatures, and when heated, burns with a dark-red light and is completely con- 
 verted into anhydrous baryta. This oxide is however more readily obtained by igniting 
 the nitrate or carbonate of barium. 
 
 Preparation. 1. Nitrate of barium is heated in a porcelain crucible, or better in a 
 porcelain retort, till it is completely decomposed, and no more red vapour or free 
 oxygen is given off. The heat should be moderate at first, because the nitrate fuses 
 and froths very much; but towards the end of the process, it must be raised to bright 
 redness. If the heat is too long continued, the baryta is apt to absorb carbonic acid 
 and oxygen from the fire. 
 
 It is not convenient to use a platinum crucible in this process, because baryta attacks 
 platinum rather strongly at high temperatures, and if a Cornish or Hessian crucible 
 be used, the baryta becomes contaminated with silica, alumina, oxide of iron, and 
 other matters derived from the crucible. A porcelain vessel is attacked in the same 
 manner, though less strongly, and the baryta prepared in it always contains small 
 quantities of alumina and silica. This contamination, and likewise the inconvenience 
 arising from the frothing of the mass, may be obviated in some cases by mixing the 
 nitrate with rather more than its own weight of pounded sulphate of barium (heavy 
 spar). Such a mixture does not fuse, and may therefore be heated in an earthen 
 crucible without attacking it (Mohr, Ann. Ch. Pharm. xxvii. 27). This process is 
 very convenient when the baryta is to be used for purposes for which the presence of 
 the sulphate is not objectionable, as for preparing baryta-water or the hydrate. 
 
 2. On the small scale, baryta may be conveniently prepared by igniting the iodate 
 of barium, which readily gives up all its iodine and f of its oxygen without fusion or 
 frothing (2I0 3 Ba = Ba 2 + FO 5 ). 3. Carbonate of barium exposed to the strongest 
 heat of a forp.-fire is converted into baryta (Abich), and at an ordinary white heat, 
 when mixed with S 1 6 of its weight of lamp-black or charcoal, and made into a thick 
 
BARIUM: OXIDES. 505 
 
 paste with oil ; the mixture should be heated in an earthen crucible lined with lamp- 
 black, and having a close-fitting cover. Baryta is prepared by this process on the large 
 scale from Witherite, to be used in separating crystallised sugar from molasses 
 (Leplay and Dubrunfaut, Sill. Am. J. [2] xvi. 276). Baryta is also prepared on 
 the large scale by igniting a mixture of the carbonates of barium and calcium in a 
 current of aqueous vapour. (Jacquelain, Compt. rend, xxxii. 877.) 
 
 Properties. Greyish-white, friable mass, of specific gravity 4'7 (Karsten); 5*54. 
 (Filhol). It is strongly alkaline, caustic, and poisonous. It melts only at the 
 strongest heat of a forge-fire, or in the flame of the oxyhydrogen blowpipe, forming a 
 lead-grey slag. It is a non-conductor of electricity, but may be decomposed by the 
 electric current, with the intervention of mercury, yielding barium and oxygen (p. 560). 
 Potassium deoxidises it at a red heat. Heated in vapour of sulphide of carbon, it forms 
 carbonate and sulphide of barium : 
 
 3Ba 2 + OS 2 = C0 8 Ba 2 + 2Ba 2 S. 
 
 With water, it forms a hydrate (see below). It unites with alcohol and wood- 
 spirit, forming the compounds Ba 8 0.2C 2 H 6 and Ba 2 0.2CH 4 0. It dissolves readily 
 in dilute nitric and hydrochloric acid, and in some other acids; with many acids, 
 it forms insoluble salts. When vapour of sulphuric anhydride is passed over baryta, 
 heated to low redness in a glass tube, combination takes place attended with incan- 
 descence, and sulphate of barium, S0 4 Ba 2 , is produced. 
 
 OXIDE OF BARIUM and HYDROGEN; HYDRATE OP BARIUM, BaHO or 
 BaO.HO. Hydrate of Baryta, Caustic Baryta, Hydrated oxide of Barium. Formed 
 by the action of water on anhydrous baryta (Ba 2 + H 2 = 2BaHO). When anhy- 
 drous baryta is sprinkled with water, the hydration takes place, with great evolution of 
 heat and expansion of volume. Anhydrous baryta also rapidly absorbs water from the 
 air. The hydrate is usually prepared by heating a solution of sulphide of barium (ob- 
 tained by igniting the native sulphate with coal or charcoal) with oxide of copper, till 
 a filtered portion of the liquid gives a white instead of a black precipitate with lead- 
 salts. Another mode of preparation is to decompose the nitrate of barium with 
 caustic soda. A solution of soda of specific gravity I'lO to 1*15, whose strength has 
 been previously determined, is mixed with an equivalent quantity of finely pounded 
 nitrate of barium, the liquid being kept in a state of ebullition, and water being added 
 from time to time in small portions to facilitate the solution of the nitrate; and when 
 the whole is dissolved, the boiling liquid is rapidly filtered, if necessary, through a 
 folded filter into a bottle which can be well closed. On cooling, it deposits an abundant 
 crop of crystals of the hydrate, which may be freed from the mother-liquor by draining, 
 or better by means of a centrifugal machine. The crystals retain but a very small 
 quantity of nitrate, and may be freed from it by recrystallisation. Chloride of barium 
 may also be used in this preparation, instead of the nitrate, but the presence of small 
 quantities of chloride of sodium in the product is more likely to be detrimental in the 
 use of the baryta, than that of the nitrate. (Mohr, Arch. Pharm. [2] Ixxxviii. 38.) 
 
 Hydrate of barium crystallises from its aqueous solution in transparent, colourless, 
 four or six-sided prisms with four-sided summits. They contain 4 at. water : BaHO 
 4H 2 0; dissolve in 20 pts. of water at 15 C. and in 2 pts. of boiling water. The 
 aqueous solution, Baryta-water, has a strong alkaline reaction, is highly caustic, and 
 rapidly absorbs carbonic acid from the air, forming a film of carbonate on the surface. 
 
 The crystals are efflorescent, and in vacuo over oil of vitriol, give off of their water 
 of crystallisation, leaving 2BaHO.H 2 O. At 100 C. they melt, giving off 1 at. water, 
 and at a red heat, the remainder of the water of crystallisation is given off, leaving 
 the pure hydrate BaHO (Bloxam, Chem. Soc. Qu. J. xiii. 49). This, when heated 
 alone, is not reduced to anhydrous baryta below a red heat, but when heated in a 
 stream of carbonic anhydride, it is easily converted into carbonate of barium, with 
 elimination of water: 
 
 2BaHO + CO 2 = COW + H 2 0. 
 
 Heated in a current of air, it takes up oxygen and is converted into peroxide of 
 barium, also with elimination of .water. (Boussingault.) 
 2BaHO + = 2BaO + H 2 0. 
 
 Hydrate of barium is extensively used as a chemical reagent, viz. for the estimation 
 of carbonic acid, for precipitating metallic oxides, and especially for separating mag- 
 nesia from the alkalis. 
 
 PEROXIDE OF BARIUM, BaO or BaO*. Produced by heating anhydrous baryta 
 or hydrate of barium to low redness in a current of pure oxygen, or of air free 
 from carbonic acid. Pure anhydrous baryta absorbs oxygen with facility ; the hy- 
 drate less readily, because it melts at the temperature required for the absorption : 
 
606 BARIUM: PEROXIDE PHOSPHIDES. 
 
 the absorption may however be rendered rapid by mixing the hydrate of barium with 
 lime and magnesia in sufficient quantity to prevent fusion, and keeping the mass in a 
 porous state, so that the oxygen may penetrate it thoroughly. Peroxide of barium 
 may also be produced by sprinkling red-hot baryta with four times its weight of 
 pounded chlorate of potassium in successive small portions. Chloride of potassium is 
 formed at the same time, and on washing out this salt with water, the peroxide 
 remains in the form of a hydrate. 
 
 Peroxide of barium is a grey powder, somewhat more fusible than anhydrous baryta. 
 At a strong red heat, it evolves oxygen and is converted into baryta, and when vapour 
 of water is passed over it at a red heat, it likewise gives up half its oxygen and is con- 
 verted into hydrate of barium. The absorption of oxygen by hydrate of barium at a 
 red heat, and its subsequent evolution when the resulting peroxide is heated in a 
 stream of aqueous vapour, has been proposed by (Boussingault, Ann. Ch. Phys. 
 [3] xxx. 5) as a means of extracting oxygen from the air by a continuous process. 
 Hydrate of barium mixed with lime and magnesia, as above described, is heated in a 
 porcelain tube through which a current of air previously freed from carbonic acid is 
 drawn by an aspirator : and as soon as the conversion of the hydrate into peroxide is 
 complete, the current of air is stopped, the temperature is raised, and vapour of water 
 is passed through the tube as long as oxygen continues to be given off. Anhydrous 
 baryta may also be used instead of the hydrate, being first converted into peroxide as 
 above, and the peroxide then decomposed by heating it to bright redness without 
 passing aqueous vapour over it : but the temperature required for this decomposition 
 is much higher ; and moreover if the baryta contains small quantities of silica and 
 alumina, which is often the case, it cakes into a very hard mass after frequent exposure 
 to a high temperature, and will then no longer absorb oxygen with facility. 
 
 Peroxide of barium is readily decomposed by carbon, phosphorus, sulphur, hy- 
 drogen, and the metals, at a red heat, and by sulphydric acid at ordinary temperatures. 
 Heated over a large spirit-lamp in a rapid current of carbonic oxide, it becomes white- 
 hot, and at the same time small white flames burst out from its surface, probably 
 arising from the evolution of oxygen from the still undecomposed peroxide. A similar 
 but more brilliant appearance is presented when the peroxide is heated in sulphurous 
 anhydride ("Wohler, Ann. Ch. Pharm. Ixxxviii. 125). In contact with strong sulphuric 
 acid, it gives off oxygen at ordinary temperatures or when gently heated. If the tem- 
 perature of the mixture does not exceed 50 or 60 C., part of the oxygen is evolved 
 in the form of ozone ; but above 70 C., nothing but ordinary oxygen is evolved. 
 
 Peroxide of barium thrown into water diffuses itself through the liquid and forms a 
 hydrate, probably containing Ba0.3H 2 0. The same hydrate is precipitated in crys- 
 talline scales when peroxide of hydrogen is added to strong baryta- water ; it is 
 slightly soluble in cold water, but decomposes at the boiling heat, yielding free oxygen 
 and hydrate of barium. 
 
 Both the anhydrous peroxide and the hydrate dissolve in excess of water acidulated 
 with hydrochloric acid, forming chloride of barium and peroxide of hydrogen, without 
 evolution of oxygen (BaO + HC1 = BaCl + HO). When the peroxide is mixed 
 with acidulated water in presence of oxide of silver, peroxide of manganese, peroxide 
 of lead, &c., oxygen is evolved, both from the peroxide of barium and from the other 
 oxide, so that the peroxide of barium here acts as a reducing agent (see CHEMICAL 
 AFFINITY and PEROXIDE OF HYDROGEN). Oxide, chloride, sulphate, or carbonate of 
 silver, introduced into an acid solution of peroxide of barium, is partly reduced to 
 metallic silver, the quantity thus reduced being, however, always less than that which 
 is equivalent to half the oxygen in the peroxide of barium (Ba 2 O.O). The quantity 
 reduced increases with the amount of silver-salt present, and diminishes as the tem- 
 perature is higher. A small quantity of the silver-compound, or of any similar sub- 
 stance, is capable of decomposing a large quantity of peroxide of barium. Iodine, on 
 the other hand, decomposes an exactly equivalent quantity : BaO + I = Bal + 0. 
 (Brodie, Phil. Trans. 1850, 759.) 
 
 BARIUM, OXYC-EW-SAIfTS OP. The general characters and reactions are 
 described at p. 502. For the special descriptions, see the several ACIDS. 
 
 BARIUXVI, OXYSUIiPHIDES OP. A solution of sulphide of barium in boil 
 ing water, left to stand in a close vessel, first deposits crystals of hydrate of barium, and 
 the liquid decanted therefrom yields scaly crystals, whose composition is nearly ex- 
 pressed by the formula Ba 14 S 3 4 .58H 2 0, and afterwards granular crystals, consisting of 
 Ba 4 S0.10H 2 O. A moderately concentrated solution of the sulphide deposits, after 
 about two months, large transparent tabular crystals, having the form of a hexagonal 
 dodecahedron, with truncated summits, and containing Ba 8 S 3 0.28H 2 0, or Ba 2 0.10H 2 O 
 + 3(Ba 2 8.6H 2 0) (H. Hose). These oxysulphides are very easily clecomposible, being 
 resolved by hot water into hydrate and sulphydrate of barium, of which, perhaps, they 
 are merely mixtures. 
 
BARIUM: SELENIDESULPHIDES. 507 
 
 BARIUM, PHOSPHIDE OP. BaP? When vapour of phosphorus is passed 
 over red-hot baryta, a brownish-red mixture of phosphide and phosphate of barium is 
 obtained, commonly called phosphuret of baryta, the reaction perhaps taking place in 
 the manner represented by the equation : 
 
 4Ba 2 + 6P = 5BaP + P0 4 Ba s . 
 
 It is decomposed by water, forming a solution of hypophosphite of barium, and giv- 
 ing off a mixture of spontaneously inflammable phosphoretted hydrogen gas and 
 free hydrogen. 
 
 BARIUM, SELENIDE OP. Ba 2 Se, or BaSe. Produced by exposing selenite of 
 barium to a red heat in contact with hydrogen gas or finely divided charcoal (lamp-black). 
 It is soluble in water, but decomposes at the same time, like the monosulphide, yield- 
 ing hydrate of barium, and a higher selenide of barium, the solution of which is de- 
 composed by acids, with evolution of selenhydric acid and precipitation of selenium. 
 
 BARIUM, SULPHIDES OP. The protosulphide, Ba*S, or BaS, is ob- 
 tained by passing sulphydric acid or vapour of sulphide of carbon over red-hot baryta, 
 or by reducing pulverised sulphate of barium in a stream of hydrogen or carburetted 
 hydrogen. Either of these processes yields a very pure product ; but for preparation 
 on the larger scale, the native sulphate of barium is heated to bright redness with 
 carbonaceous matter. If charcoal is used, it must be thoroughly well incorporated 
 with the heavy spar, otherwise the reduction will be imperfect, as no fusion takes 
 place. The admixture of resin, oil, or starch is advantageous, to bind the mass toge- 
 ther and produce partial fusion ; but a much better method is to mix the powdered 
 sulphate with about | of its weight of bituminous coal, and heat the mixture in a 
 crucible to full redness for an hour ; the tarry matter of the coal then penetrates 
 thoroughly into the mass, so that every particle of the sulphate comes well in contact 
 with the reducing matter. 
 
 The mass thus obtained consists of sulphide of barium mixed with excess of car- 
 bonaceous matter and undecomposed sulphate ; the sulphide of barium may be ex- 
 tracted by treating the mass with a sufficient quantity of hot water, and crystallised. 
 Another method is to ignite a mixture of 100 pts. heavy spar, 200 common salt, and 
 15 pts. charcoal powder in a reverberatory furnace, and extract the sxilphide of barium 
 by hot water. The use of the chloride of sodium is to promote fusion. (Kuczinski, 
 Repertory of Patent Inventions, 1835, p. 151.) 
 
 Pure sulphide of barium is a white mass, having a hepatic odour and alkaline taste, 
 and easily soluble in water. Exposed to the air, it absorbs water and carbonic acid, 
 and is converted into carbonate, with evolution of sulphuretted hydrogen. When 
 heated in the air, it oxidises but slowly, but when heated to redness in an atmosphere 
 of aqueous vapour, it is converted into sulphate of barium, with elimination of hydrogen. 
 
 Sulphide of barium dissolved in water is easily decomposed by boiling with oxide of 
 copper, oxide of iron, $'c., forming hydrate of barium and sulphide of copper, &c. 
 Hydrochloric, nitric, carbonic acid, $c. decompose it, eliminating sulphuretted hydrogen, 
 and forming chloride, nitrate, &c. of barium. Chlorine, bromine and iodine decompose 
 it, with formation of the corresponding salts and deposition of sulphur. Sulphide of 
 barium is indeed the material most generally used for preparing the other compounds 
 of barium. 
 
 A mixture of sulphide of barium with the sulphate, such as is obtained by igniting 
 the sulphate with an insufficient quantity of carbonaceous matter (gum-tragacanth 
 answers well, because it forms a paste with the heavy spar), acquires by exposure to 
 the sun's rays the property of shining in the dark : it is called the Bolognian phos- 
 phorus. 
 
 With water, protosulphide of barium forms hydrate and sulphydrate of barium : 
 
 Ba 2 S + H 2 = BaHO + BaHS. 
 
 The quantity thus decomposed varies with the quantity and temperature of the 
 water. When crude sulphide of barium, prepared by igniting the sulphate with 
 carbonaceous matter, is treated nine times in succession with a quantity of cold 
 water less than sufficient to dissolve the whole, the mass being digested for twenty- 
 four hours each time in a closed vessel, the first two solutions obtained are of a 
 pale yellow colour; yield a large quantity of sulphuretted hydrogen and a pre- 
 cipitate of sulphur, when treated with hydrochloric acid ; and form with chloride 
 of manganese, a flesh-coloured precipitate of sulphide of manganese mixed with free 
 sulphur, sulphuretted hydrogen being likewise evolved : hence these solutions contain . 
 sulphydrate of barium (BaHS) together with a polysulphide of barium. The third 
 solution behaves like a solution of protosulphide of bariiim containing a slight excess 
 of sulphuretted hydrogen. The fourth is of the same character, but contains a 
 
508 BARIUM BAROMETER. 
 
 slight excess of baryta. This excess goes on continually increasing in the fifth, sixth 
 and seventh solutions : and the eighth and ninth behave like pure baryta-water, 
 yielding with chloride of manganese a white precipitate of manganous oxide. If the 
 crude sulphide is at once treated with a quantity of water sufficient to dissolve the 
 whole of the sulphide, the solution exhibits the characters of the pure protosulphide : 
 it may however be a mixture of hydrate and sulphydrate of barium (see the above 
 equation). A solution of sulphide of barium in not too large a quantity of water, 
 kept for some years in a stoppered bottle, deposits, first crystals of hydrate of barium, 
 then scales which are a mixture of crystallised hydrate of barium and the hydrated 
 protosulphide (Ba 2 S.3H 2 0), and afterwards double six-sided pyramids containing the 
 same substances, but much richer in sulphide of barium. The mother-liquor boiled 
 down in a retort, evolves a continuous current of sulphuretted hydrogen, and on cooling 
 deposits hydrated sulphide of barium in the form of a white powder, while sulphide of 
 barium and hydrogen remains in solution. 
 
 Hydrated Sulphide of Barium, Ba 2 S.3H 2 0, is a white powder, which soon turns 
 yellow. When treated at once with a quantity of water sufficient to dissolve it 
 perfectly, it yields a solution which when mixed with a manganous salt, yields a pre- 
 cipitate of sulphide of manganese (Mn 2 S) without evolution of sulphuretted hydrogen ; 
 but a smaller quantity of water extracts sulphydrate of barium and leaves hydrate of 
 barium undissolved. 
 
 Sulphydrate of Barium, BaHS, or BaS.HS. Baryta-water, or protosulphide of 
 barium reduced to a paste with water, and warmed, is saturated with sulphydric acid, the 
 solution evaporated apart from the air, and cooled, when crystals of baryta and yellow 
 prisms are formed. The remaining liquid is either evaporated in a confined space, when 
 white opaque prisms are obtained, or mixed with alcohol, filtered from the sulphur 
 and hyposulphite of barium produced by air contained in the alcohol, and cooled 
 down to 10 C. ; in this way, colourless and transparent four-sided prisms are pro- 
 duced. Also when baryta or either of its hydrated compounds is allowed to crystallise, 
 together with sulphide of barium, from an aqueous solution of protosulphide of barium, 
 by evaporation in a retort and cooling, and the residual liquid (which is of a yellowish 
 cokmr, from the air not being perfectly excluded) further evaporated and cooled, it 
 solidifies to a crystalline mass of sulphydrate of barium (H. Rose). The crystals 
 contain water, which they lose when heated, becoming white at the same time. When 
 exposed to the air, they effloresce and turn white, while hyposulphite and sulphate of 
 barium are formed. In a retort, they lose their water of crystallisation without fusing, 
 and then evolve sulphydric acid as the temperature approaches redness, leaving dark 
 yellow protosulphide of barium, which becomes white as it cools. An aqueous solution 
 precipitates chloride of manganese, with escape of sulphydric acid gas (Berzelius, 
 Pogg. Ann. vi. 441). The salt, when boiled, evolves sulphydric acid. With iodine, it 
 forms iodide of barium and free hydriodic acid, sulphur being set free. It is insoluble 
 in alcohol. (H. Kose.) 
 
 and 2*8 pts. of sulphate of barium, remain behind (Vauquelin). When, the 
 moistened trisulphide is heated to redness and vapour of water is passed over it, sul- 
 phuretted hydrogen is given off, and sulphate of barium is formed. (Gray-Lussac.) 
 
 Pentasulphide of Barium, Ba 2 S 5 , is obtained in solution, by boiling the proto- 
 sulphide or the sulphydrate with sulphur (H. Rose); also, together with hyposulphite 
 of barium, by boiling baryta-water with sulphur. The solution is yellow, bitter, 
 alkaline and caustic ; leaves a pale yellow amorphous mass when evaporated in vacuo; 
 and is decomposed by exposure to the air, with deposition of sulphur and formation of 
 hyposulphite of barium. 
 
 BARLEY. See CEREALS. 
 
 BARTJHARDTITE. A sulphide of copper and iron, 2Cu 4 S.Fe' l S 3 , containing 
 traces of silver, found in a mine in Earnhardt's Land, and other localities in North 
 Carolina. Bronze-yellow, with metallic lustre, sometimes dull and opapue. Fracture 
 conchoi'dal ; no cleavage. Specific gravity 4-521. Hardness = 3-5. Brittle. Streak 
 greyish-black, somewhat shining. Tarnishes in the air, especially in contact with 
 moisture, acquiring a brown or rose-red colour. Before the blowpipe, it gives the 
 reactions of iron and copper. (G-enth. J. pr. Chem. Ixiv. 468.) 
 
 BAROCAXiCXTEi. Syn. with BAJRYTOCAXCITB. 
 
 BAROXiXTi:. Syn. with WITHERITE. 
 
 BAROZVXSTER (/3apos weight and perpov measure). The barometer is an instru- 
 
BAROMETER. 509 
 
 ment employed to measure the pressure or weight of the atmosphere. It consists essen- 
 tially of a continuous body of liquid, generally mercury, from one part of the upper 
 surface of which all pressure is removed, while the atmosphere still presses upon the 
 remainder of the surface. It is a law of hydrostatics that, in a heavy fluid, the pressure 
 at all points in a horizontal plane must be uniform, in order that there may be equi- 
 librium. The surface of the mercury cannot, then, remain in one plane, as it does 
 when the atmosphere presses equally on every part, but it must rise where protected 
 from the atmosphere, until the pressure of the portion thus rising exactly balances 
 and replaces the pressure of the atmosphere. Thus in fig. 92, the surface of mer- 
 cury on which the atmosphere presses is at A, and the glass tube A B, having been 
 perfectly emptied of air and every other fluid, the mercury has risen to B, so that the 
 perpendicular column of mercury A B exerts a pressure at the horizontal plane A, exactly 
 equal to the pressure of the atmosphere at A. 
 
 Now supposing mercury to be always of one specific gravity, the length of the 
 barometric column will be exactly proportional to the weight or pressure of the atmo- 
 sphere, and thus a length expressed in inches or parts of a metre becomes a convenient 
 expression for a weight. It is well, however, to bear in mind the real pressures indi- 
 cated, which are easily determined, as in the following example : 
 
 29 - 872 inches = mean height of barometric column for noon at Greenwich. 
 13-568 = specific gravity of mercury at 60 F. 
 99 7 '13 7 oz. avoirdupois = weight of one cubic foot of water at 62 F. 
 
 "' gx7 ' 11 ' 7 - 233 ' 879 oz - - uw lbs - the 
 
 spheric pressure for noon at Greenwich on every square superficial inch. 
 
 Barometer at 28 inches Atmospheric pressure 13*70 pounds 
 29 14-19 
 
 30 14-68 
 
 31 15-17 
 
 When any other liquid, is used, the height of the barometric column will be in- 
 versely as the specific gravity. Thus the height of a column of water corresponding 
 
 1 o.Q 
 
 to 29-872 inches of mercury at 60 F. is 29-872 x -^-7^77, or 405-3 inches or 3377 feet; 
 
 I'OOU 
 
 similarly a column of sulphuric acid would stand 29 -87 2 x , or 219 inches high. 
 
 A full account of a water barometer constructed for the Koyal Society by Professor 
 Daniell will be found in Phil. Trans, cxxii. (1832), 539. 
 
 CONSTRUCTION OF THE BAROMETER. All that is necessary to construct a barometer is 
 to seal a glass tube about three feet along at one end, to fill it perfectly with mercury, 
 and putting the finger over the open end, to invert the tube into a vessel of mercury. 
 On withdrawing the finger, the mercurial column descends a few inches, and a measure 
 being applied, the height of the column remaining is found. But to attain accuracy, 
 great precautions are required at every step. 
 
 If any air remain in the tube, by adhering to the glass, it will rise into the space 
 above the mercury, and its pressure, partly counteracting that of the atmosphere, will 
 depress the barometric column. Most of the air may be got out by shaking the 
 mercury in the tube, but some will certainly remain, to eliminate which, the tube 
 must be boiled as follows : Fill only about six inches of the tube with mercury, and 
 gradually heat it over a strong flame or a charcoal fire until the mercury has boiled 
 for a few moments. At the same time, heat another portion of mercury, that it may 
 not crack the hot tube, and with it fill a few inches more of the tube. Expose this 
 new part chiefly to the flame until it boils, and thus proceed, alternately pouring in a 
 little mercury and then boiling, until the tube is almost full. It would be well to 
 anneal the tube, if a large one, while cooling, to prevent fracture. When cold, fill it 
 entirely with mercury, already boiled, and invert, with great precautions, to prevent 
 entrance of air. Any kind of dirt entering also will prove very detrimental, and the 
 tube, in the first place, before sealing, should be thoroughly sponged out with whiting 
 and spirits of wine. 
 
 The mercury used must be perfectly pure, otherwise it will be thick, sluggish, and 
 dirty, as well as somewhat false in specific gravity. To purify it, agitate with diluted 
 nitric acid or sulphuric acid, and keep it under the acid, if possible, for a week or more, 
 afterwards washing with fresh acid and distilled water. Carefully distilled mercury 
 is pure enough, except that the dissolved oxide of mercury must be removed by treat- 
 ment with sulphuretted hydrogen water, or dilute sulphide of ammonium. 
 
 Many forms of the barometer have been contrived since its first discovery by Torri- 
 
510 
 
 BAROMETER. 
 
 celli; but, except in rendering the instrument portable and unalterable, no improve- 
 ment has ever, or perhaps can ever be made on the original simple form. In fact, the 
 most perfect barometer existing, the Great Standard at the Kew Observatory, men- 
 tioned further on, is also the most simple that could be imagined. 
 
 We shall, therefore, content oiirselves with describing those forms of the barometer 
 which can be recommended to the observer of the present day for their accuracy and 
 
 convenience. 
 
 s. 8893 
 
 88 
 
 A 
 
 89 
 
 In fig. 88 is shown the PORTABLE STANDARD BAROMETER, as first invented byFortin 
 of Paris, and now made, amongst others, by Negretti and Zambra of Hatton Garden, 
 London, at a cost of eight guineas. 
 
 The barometer tube has an internal diameter of '39 or '40 inch, and the air is per- 
 fectly driven out by the usual process of boiling. The cistern (fig. 89) is composed 
 partly of a glass cylinder G, of boxwood sides and top, w and w', and of a leather bag, t, 
 the bottom of which can be raised or lowered by the finger-screw, s. The whole is, 
 of course, held together by a brass casing, and the barometer tube, the lower end of 
 which is contracted, is connected with the cistern by a leather joint at M. 
 
 To make an observation of this barometer, the lower surface of the mercury must 
 first be adjusted so as just to touch the ivory fiducial point p (fig. 89), by turning 
 the screw s. The moment of exact contact may be very accurately observed, if the 
 mercury be properly clean and bright, by watching when the ivory point and its 
 reflection just meet ; if the mercury be even -^^ of an inch too low, light will 
 appear between the point and mercury; while, if too high, a small depression, 
 instantly detected by reflected light, will be caused in the mercurial surface by the 
 ivory point. 
 
 Next, the upper surface of the mercurial column is observed by adjusting the lower 
 edge of a moveable brass cylinder, so that it shall visually be the tangent to, that is 
 shall just touch, the curved surface of the mercury. To avoid the error of parallax, 
 the line of vision must be exactly horizontal. The scale of inches, with the assistance 
 of the vernier engraved on the moveable cylinder, then gives the actual height of the 
 column, subject to index error, within the TT ^ part of an inch. But the observer, with 
 a little practice, will soon discriminate the ^ part by the naked eye. 
 
 A Barometer should never be carried about in its ordinary upright position; for 
 
BAROMETER. 611 
 
 the mercurial column, being delicately balanced against the weight of the air, will be 
 found to -vibrate, or as it is said, to pump rapidly up and down when the barometer 
 suffers any vertical disturbance. Not only might bubbles of air adhering to the lower 
 part of the tube be thus carried up, but the mercury violently striking the sealed 
 and vacuous end, might shatter a tube that was not very strong. To render this 
 barometer portable, the handscrew at s must be screwed up, and the instrument 
 gently inclined at the same time, until the mercury fills the whole of the tube, and 
 almost the whole of the cistern ; it is then to be inverted and kept or carried about as 
 nearly as possible in this position until again safely suspended. A board and bracket, 
 not shown in the figures, accompany this barometer, as also an arrangement of 
 three screws, by which it may be secured motionless in the vertical position, which it 
 of course assumes when free. Such a barometer is very suitable and quite good enough 
 for a laboratory, or for a series of meteorological observations. It is the form of baro- 
 meter most esteemed on the Continent. 
 
 Of MOUNTAIN BAROMETERS, which require to be far more portable and secure from 
 accident than that above described, the best is Gray-Lussac's form (see Ann. de 
 Chimie, 1816, i. 113), as improved by Bun ten, and drawn in. fig. 90 from an instru- 
 ment by Negretti and Zambra. Its tube is in the form of a syphon, of which the 
 parts D E and F o have an uniform diameter of '2 inch, while the part E F is a capil- 
 lary tube, with a bore of about -05 inch. The end of the tube at G is sealed, but a 
 minute and somewhat sunken hole is pierced about an inch below the end, so that air 
 may pass freely in or out, but not the mercury. At E is a pipette or air trap, shown 
 on a larger scale in fig. 91, contrived by Bunten, so that even if air pass up the tube 
 E F, it will collect at E, since it is scarcely possible that it should find its way through 
 the capillary communication (H, fig. 91) into the upper part of the tube. 
 
 The tube is loosely packed in a brass tube-case, through two slits in which the 
 upper and lower surface of the mercury may be observed in the same manner as the 
 upper surface in the Fortin barometer. There are two divided scales, both 9 inches 
 long, and measured from the lowest point of the lower scale, and the difference of the 
 readings is the height of the barometric column. The verniers read to the ~^ of 
 an inch. 
 
 NEWMAN'S STANDARD BAROMETER is well known, and has long been relied upon in 
 other countries as well as this. The tube has a diameter of '5 or '6 inch, and stands 
 in a plain cylindrical glass cistern. The graduated scale is of brass, affixed to a brass 
 rod passing down the inside of one of the upright supports, and terminating below in 
 a conical ivory point, which by an endless screw and wheel is very accurately ad- 
 justed to contact with the mercury. In this respect the construction is superior to 
 that of the Fortin barometer, because the mercury when raised or lowered, as in the 
 latter, may not at once assume its true position, owing to adhesion. Mr. Newman has 
 adopted a method of filling his barometer-tubes in vacuo, and of boiling them under 
 diminished pressure, which obviates all oxidation and fouling of the tubes. 
 
 THE GREAT STANDARD BAROMETER of the Kew Observatory, constructed by the 
 late Mr. Welsh, has a tube I'l inch in bore, and as it was found impossible to fill so 
 large a tube satisfactorily in the ordinary way, the following excellent method was 
 adopted: To the upper end of the barometer tube AB (Jiff. 93) was attached a 
 capillary tube A D E F, much contracted at D, with a small bulb at E, drawn out at F 
 to a fine point, and hermetically sealed. To the lower end of the large tube was 
 attached 10 inches of a smaller tube B c G, having a bore of 0*3 inch, and to that 
 again was added about 6 inches of capillary tube G H. A bulb of f of an inch was 
 blown at G, and the small tube finally bent into a syphon form at B. The end H of 
 the capillary tube was now connected with a good air-pump, and the air very slowly 
 extracted, at the same time that the whole tube was strongly heated by passing a 
 large spirit flame along it. When the air had been as well as possible extracted, and 
 whilst the pump was still in action and the heat still applied, the capillary tube G H 
 was sealed at i by a blowpipe flame. When the tube had cooled, it was placed at a 
 small inclination with the end F in perfectly pure mercury, which had been previously 
 boiled, and the point being broken off, the mercury rose until the bulb at G was more 
 than half filled. The point F was then again sealed, the capillary tube remaining 
 quite filled with mercury. When the glass at F had cooled, the whole tube was in- 
 verted, the mercury now separating at the contracted part D, leaving the tube from D 
 to F filled, or very nearly so, and from D to A perfectly vacuous. The operation was 
 completed by sealing the tube at K, removing the portion K D E F, placing the bend B 
 in the cistern of the barometer, and breaking off the tube c G at the point c. 
 
 The tube finally adopted at Kew, is perfectly free from air in the portion B, which 
 is 9 inches long; it is mounted in an open brass frame (fig. 92), adjusted to verti- 
 cality by screws at s ; at c c' are two steel rods, the first terminating below in a conical 
 point, the second in a knife-edge, and both adjusted so as just to touch the surface of 
 
612 BAROMETER. 
 
 the mercury in the cistern. The height of the mercurial column is then easily observed 
 by a cathetometer placed five feet off, the telescopic wire of which is made alternately 
 to bisect a mark on the head of the rods c or c', and to form a tangent to the mercurial 
 surface at B. The difference of the readings on the divided scale of the cathetometer, 
 added to the known length (3-515 for c) between the point and end of the steel rod, 
 and the mark on its head, gives the actual length of the barometric column. The 
 cistern of this barometer stands 3 3 '9 feet above the mean sea-level. (Phil. Trans. 
 [1856] p. 507.) 
 
 A very interesting account of the construction of the Eoyal Society's Standard 
 barometer by DanieU, will be found in his Meteorological Essays, p. 353. See also 
 Mr. Baily's Description of a New Barometer, Phil. Trans, cxxvii. 431 ; and Hudson, 
 Phil. Trans. [1832] p. 575. 
 
 We will now consider the precautions and corrections necessary in obtaining the true 
 atmospheric pressure with exactness. 
 
 CORRECTION FOR CAPACITY. It is obvious that in proportion as the barometer 
 stands higher, so much more mercury there must be in the tube, and consequently so 
 much less in the cistern. We should not then get the true variations in the length of 
 the mercurial column, by noticing the top of the column only, since the base of the 
 column also varies, and a correction must obviously be made for the amount of the 
 variation. 
 
 This correction, indeed, is not required in any of the barometers above described, 
 because observations or adjustments are made both at the upper and lower surfaces 
 of mercury. But in many other barometers, the scale is measured truly from 
 the lower surface of the mercury, only when the column is at one particular height, 
 called the neutral point, usually determined by the barometer-maker, and marked on 
 the instrument. When the column is higher or lower than this point, the mercury in 
 the cistern must be lower or higher in a proportion depending on the sectional areas 
 of the tube and cistern. If JF/be the height of the neutral point, and h the observed 
 height of the barometer, the correction for capacity is 
 
 < diameter of tube \ 2 . . __ 
 (diameter of cistern) ^ 
 
 In the marine barometer adopted by the Board of Trade, this correction is actually 
 performed upon the divided scale, so that the inch divisions are about | less than 
 real inches. In any syphon barometer, like that of Gfay-Lussac, in which both legs 
 are of equal diameter, the correction for capacity is made by doubling the variations 
 in height of one surface, and Gray-Lussac recommends this method when great nicety 
 is not required; but measurements of both surfaces are evidently necessary for 
 certainty. 
 
 CORRECTION FOR TEMPERATURE. The length of the barometric column is propor- 
 tional to the pressure which it has to measure only so long as the specific gravity of 
 mercury is constant. Now mercury expands ]0 ^ 00 of its own volume when its 
 temperature rises one degree (Fahr.), and its density of course varies inversely. Hence 
 all readings of the barometer must be reduced to what they would be at one uniform 
 temperature, that of 32 Fahr., when the specific gravity becomes 13-60. The brass 
 scale by which the height is measured also expands by heat, and is only of the standard 
 length when at a temperature of 62 F. (for the English yard). 
 
 To ascertain the temperature of the barometer, a thermometer is always attached. 
 This should be placed half way up the barometer tube, with the bulb close to the tube, 
 and well covered up from the atmosphere. The barometer should be placed in a 
 room of which the temperature changes as little and as slowly as possible. 
 
 If h be the observed height of the barometer, and t its temperature in degrees Fahr., 
 the height reduced to 32 F. is 
 
 -OOOlOOl^- 32)- 000010434(<- 62) 
 1* -0001001(z!- 32) 
 
 but it is quite exact enough to subtract (or add if t be less than 29 Fahr.) the fol- 
 lowing correction : 
 
 ;i}(*-32)(-0001)-(*-62)(-00001)| 
 
 The reader will observe that the cubic, not the linear, expansion of mercury is used 
 in these formulae, for it is on the cubic expansion that the specific gravity depends. 
 
 The correction is most conveniently obtained, however, from a table such as that 
 on the following page, which applies to barometers with brass scales, extending from 
 the cistern to the top of the mercurial column. 
 
BAROMETER. 
 
 513 
 
 Table for the Temperature-correction of the Barometer. 
 
 Temp. 
 F. 
 
 28-5 
 inch. 
 
 29-0 
 inch. 
 
 29-5 
 inch. 
 
 300 
 inch. 
 
 30-5 
 inch. 
 
 Temp. 
 F. 
 
 28-5 
 inch. 
 
 29-0 
 inch. 
 
 29-5 
 inch. 
 
 30-0 
 inch. 
 
 30-5 
 inch. 
 
 31 
 
 006 
 
 007 
 
 007 
 
 007 
 
 007 
 
 61 
 
 083 
 
 084 
 
 086 
 
 087 
 
 089 
 
 32 
 
 009 
 
 009 
 
 009 
 
 009 
 
 010 
 
 62 
 
 085 
 
 087 
 
 088 
 
 090 
 
 091 
 
 33 
 
 012 
 
 012 
 
 012 
 
 012 
 
 012 
 
 63 
 
 088 
 
 089 
 
 091 
 
 093 
 
 094 
 
 34 
 
 0)4 
 
 014 
 
 015 
 
 015 
 
 015 
 
 64 
 
 090 
 
 092 
 
 094 
 
 095 
 
 097 
 
 35 
 
 017 
 
 017 
 
 017 
 
 018 
 
 018 
 
 65 
 
 093 
 
 095 
 
 '096 
 
 098 
 
 100 
 
 36 
 
 019 
 
 020 
 
 020 
 
 020 
 
 021 
 
 66 
 
 096 
 
 097 
 
 099 
 
 101 
 
 102 
 
 37 
 
 022 
 
 022 
 
 022 
 
 023 
 
 023 
 
 67 
 
 098 
 
 100 
 
 102 
 
 103 
 
 105 
 
 38 
 
 0'24 
 
 025 
 
 025 
 
 026 
 
 026 
 
 68 
 
 101 
 
 102 
 
 104 
 
 106 
 
 108 
 
 39 
 
 027 
 
 027 
 
 028 
 
 028 
 
 029 
 
 69 
 
 103 
 
 105 
 
 107 
 
 109 
 
 110 
 
 40 
 
 029 
 
 030 
 
 030 
 
 031 
 
 031 
 
 70 
 
 106 
 
 108 
 
 109 
 
 111 
 
 113 
 
 41 
 
 032 
 
 033 
 
 033 
 
 C34 
 
 034 
 
 71 
 
 108 
 
 110 
 
 112 
 
 114 
 
 116 
 
 42 
 
 034 
 
 035 
 
 036 
 
 036 
 
 037 
 
 72 
 
 111 
 
 113 
 
 115 
 
 117 
 
 119 
 
 43 
 
 037 
 
 038 
 
 038 
 
 039 
 
 040 
 
 73 
 
 113 
 
 115 
 
 117 
 
 119 
 
 121 
 
 44 
 
 040 
 
 040 
 
 041 
 
 042 
 
 042 
 
 74 
 
 116 
 
 118 
 
 120 
 
 122 
 
 .124 
 
 45 
 
 012 
 
 043 
 
 044 
 
 044 
 
 045 
 
 75 
 
 118 
 
 120 
 
 122 
 
 125 
 
 127 
 
 46 
 
 045 
 
 015 
 
 046 
 
 047 
 
 048 
 
 76 
 
 121 
 
 123 
 
 125 
 
 127 
 
 M29 
 
 47 
 
 047 
 
 048 
 
 049 
 
 050 
 
 051 
 
 77 
 
 123 
 
 126 
 
 128 
 
 130 
 
 132 
 
 48 
 
 050 
 
 051 
 
 052 
 
 052 
 
 053 
 
 78 
 
 126 
 
 128 
 
 130 
 
 133 
 
 135 
 
 49 
 
 052 
 
 053 
 
 054 
 
 055 
 
 056 
 
 79 
 
 128 
 
 131 
 
 133 
 
 135 
 
 137 
 
 50 
 
 055 
 
 056 
 
 057 
 
 058 
 
 059 
 
 80 
 
 131 
 
 133 
 
 136 
 
 138 
 
 140 
 
 51 
 
 057 
 
 058 
 
 059 
 
 060 
 
 Ofil 
 
 81 
 
 134 
 
 136 
 
 138 
 
 141 
 
 143 
 
 52 
 
 OGO 
 
 061 
 
 062 
 
 063 
 
 064 
 
 82 
 
 136 
 
 138 
 
 14] 
 
 143 
 
 146 
 
 53 
 
 Ofi3 
 
 064 
 
 065 
 
 OG6 
 
 067 
 
 83 
 
 139 
 
 141 
 
 143 
 
 140 
 
 148 
 
 54 
 
 065 
 
 0<6 
 
 067 
 
 068 
 
 070 
 
 84 
 
 141 
 
 144 
 
 146 
 
 149 
 
 151 
 
 55 
 
 068 
 
 069 
 
 070 
 
 071 
 
 072 
 
 85 
 
 144 
 
 146 
 
 149 
 
 151 
 
 154 
 
 56 
 
 070 
 
 071 
 
 073 
 
 074 
 
 075 
 
 86 
 
 146 
 
 149 
 
 151 
 
 154 
 
 156 
 
 57 
 
 073 
 
 074 
 
 075 
 
 076 
 
 078 
 
 87 
 
 149 
 
 151 
 
 154 
 
 157 
 
 159 
 
 58 
 
 075 
 
 077 
 
 078 
 
 079 
 
 081 
 
 88 
 
 151 
 
 154 
 
 157 
 
 159 
 
 162 
 
 59 
 
 078 
 
 079 
 
 080 
 
 082 
 
 083 
 
 89 
 
 154 
 
 156 
 
 159 
 
 162 
 
 165 
 
 GO 
 
 080 
 
 082 
 
 083 
 
 085 
 
 086 
 
 90 
 
 156 
 
 159 
 
 162 
 
 164 
 
 167 
 
 The fail tables, as originally calculated by Prof. Schumacher (Jahrbuch fur 1837, 
 Astron. Nach. t. ii.), will be found in the " Eeport of the Committee of the Eoyal 
 Society on Physics," 1840. The Admiralty "Manual of Scientific Enquiry," and most 
 works on Physics and Meteorology, also contain tables, often slightly differing from 
 each other. 
 
 To obtain an approximate correction, multiply the number of inches in the height of 
 the reading by the number of degrees Fahr. above 32, and subtract -0001 inch for 
 every unit of the result. The following data are useful. 
 
 For lFahr. 
 
 Coefficient of the cubic expansion of 
 
 mercury 
 (log. 1-0001001 = 0-0000435) 
 
 Coefficient of the linear expansion) . 0000956 
 
 Coefficient of the linear expansion' 
 of brass adopted by Schumacher 
 
 Coefficient of the linear expansion) .0000048 
 of glass. \ 
 
 0001001 
 
 0000105 
 
 For lCentigra<] 
 00018018 
 
 00001722 
 
 0000188 
 
 0000086 
 
 The last must be employed instead of the coefficient of brass, when the scale is 
 engraved on the glass barometer tube, as often occurs on the Continent. Tables for 
 glass metre scales and centigrade degrees, will be found in Bunsen's Gasometry, 
 translated by Eoscoe. 
 
 THE CAPHXAKY DEPRESSION of the mercurial column is a formidable obstacle to the 
 attainment of accuracy when the tube is of small bore. For this reason, important 
 standard barometers, like that of Kew, have a large tube in which the capillary de- 
 pression is inappreciable. 
 
 The cause of the depression is, that the particles of the mercury have a much 
 stronger attraction for each other than for the glass ; a slight resultant attraction thus 
 arises, tending to draw each particle towards the general mass of mercury. The form 
 which the surface of the mercury assumes is spheroidal; the highest point of the 
 surface is to be always taken, in adjusting the edge of the vernier for an observation. 
 
 To avoid any error from the capillary depression, it is far the best way to compare the 
 barometer with an undoubted standard barometer in which the capillary depression is 
 inappreciable. The correction for capillarity is then merged into that for index error. 
 
 VOL. I. L L 
 
514 
 
 BAROMETER. 
 
 If this be not done, the bore of the barometer tube must be ascertained from the 
 barometer maker, or otherwise, and the correction then taken from the following table, 
 which is the one generally adopted for the purpose in England. 
 
 Diameter 
 
 Add to the reading for 
 
 Diameter 
 
 Add to the reading for 
 
 of tube. 
 
 
 of tube 
 
 
 
 Unboiled tubes. 
 
 Boiled tubes. 
 
 
 Unboiled tubes. 
 
 Boiled tubes. 
 
 0-60 inch. 
 
 0-004 inch. 
 
 0.002 inch. 
 
 0-30 inch. 
 
 0-028 inch. 
 
 0-014 inch. 
 
 0-50 
 
 0-007 
 
 0-003 
 
 0-25 
 
 0-040 
 
 0-020 
 
 0-45 
 
 o-oio 
 
 0-005 
 
 0-20 
 
 0-060 
 
 0-029 
 
 0-40 
 
 0-014 
 
 0-007 
 
 0-15 
 
 0-088 
 
 0-044 
 
 0-35 
 
 0-020 
 
 0-010 
 
 0-10 
 
 0-142 
 
 0-070 
 
 Continental observers have attempted to attain greater accuracy by making the 
 height of the meniscus or curved surface of the mercury an argument in the correction. 
 M. Delcros has calculated an elaborate table on this principle of which a part is here 
 given. 
 
 
 Height of the meniscus in millimetres. 
 
 Bore of the tube. 
 
 
 Millimetres. 
 
 
 
 
 
 
 
 
 
 
 
 0-2 
 
 0-4 
 
 0-6 
 
 0-8 
 
 1-0 
 
 1-2 
 
 1-4 
 
 1-6 
 
 1-8 
 
 3-0 
 
 0-24 
 
 0-48 
 
 0-70 
 
 0-90 
 
 1-07 
 
 1-20 
 
 1-32 
 
 
 
 4-0 
 
 0-12 
 
 0-24 
 
 0-35 
 
 0-46 
 
 0-55 
 
 0-63 
 
 0-71 
 
 077 
 
 
 5-0 
 
 0-07 
 
 0-13 
 
 0-19 
 
 0-25 
 
 0-30 
 
 0-35 
 
 0-40 
 
 0-44 
 
 
 6-0 
 
 0-02 
 
 0-06 
 
 0-09 
 
 0-13 
 
 0-18 
 
 0-20 
 
 0-23 
 
 0-25 
 
 0-27 
 
 7-0 
 
 o-oi 
 
 0-03 
 
 0-06 
 
 0-09 
 
 o-io 
 
 0-12 
 
 0-14 
 
 0-15 
 
 0-16 
 
 For the full tables and for a very elaborate description of the principal standard 
 barometers on the continent, the determination of their mean differences, and the 
 errors to which barometers are subject, the reader should consult a paper by Bravais 
 and Martins in Nouv. Mem. de 1'Acad. Eoy. de Bruxelles xiv. 31 (1841) ; see also 
 Dove, Repertorium der Physik, i. 37. 
 
 The capillary depression of the barometric column has been investigated mathe- 
 matically by Mr. Ivory in the Philosophical Magazine and Annals for 1828, vol. iii. 
 p. 1. [This reference is usually wrongly given to the Philosophical Transactions.] 
 
 This correction is considered unnecessary to the Gay-Lussac, or any other syphon 
 barometer, in which the two surfaces of mercury are of equal extent, and therefore 
 subject to equal capillary action. But we think that the adhesion of the mercury in 
 the lower limb of the Gay-Lussac tube, being much increased by the presence of air 
 and dust, is liable to cause inaccuracy unless carefully attended to. 
 
 The INDEX EKEOB is properly the error in the length of brass rod or scale ex- 
 tending between the two surfaces of mercury. Such error may usually be considered 
 uniform for all parts of the divided scale, which is accurately divided by a machine, 
 and the error probably arises, if at all, from the wrong adjustment of the ivory fiducial 
 point. 
 
 But the index error, as usually determined by comparison with a standard barometer, 
 comprises the capillary depression before mentioned, as well as any minute errors from 
 impurity in the mercury, from imperfect vacuum in the upper part of the tube, error 
 of the attached thermometer, and so on. Comparison with a standard, in short, secures 
 the final accuracy of the result, and no observer of the present day who desires to be 
 considered trustworthy should use an uncompared barometer. The purchaser of a 
 barometer for scientific purposes should insist on receiving with it an authentic certi- 
 ficate of its index error from comparison with the Greenwich, Kew, or Royal Society 
 Standard. The best barometer makers, Negretti and Zambra, Newman of Eegent 
 Street, or Barrow of Oxenden Street, the latter the maker to the British Meteorological 
 Society, will readily procure such a certificate. Of course a fresh comparison is neces- 
 sary if the barometer be in any way disordered or suspected of being disordered. 
 
 To compare two barometers, they should be suspended side by side, and a score of 
 simultaneous readings of each taken at intervals, if possible when the barometric 
 column is at various heights, and both rising and falling. The readings of each baro- 
 meter are to be fully and carefully corrected for temperature, according to its own 
 
 , 
 
BAROMETER, 515 
 
 attached thermometer ; the mean difference of all the readings, together with the known 
 index error of the one barometer, is the index error of the other barometer. 
 
 From the uniformity of the readings, the observer may judge either of his own skill or 
 of the character of the instruments. With good instruments and a careful observer, the 
 differences should be uniform within about y|^ of an inch, and the whole index error, 
 apart from capillary action, should not exceed ^ or ^ ; thus, in the comparison of 
 the writer's barometer by Mr. Glaisher at Greenwich, the differences of twenty read- 
 ings vary from 0-009 to 0-020, with a mean error of 0'014, apart from the 
 assumed capillary depression -008 inch, making the whole correction + '022 inch. 
 
 Treated according to the formulae of the calculus of probabilities, the probable error 
 of this determination from the mean of twenty observations is rather less than -0015 
 inch. Assuming the Greenwich standard to be absolutely correct, his probable error 
 of '0015 inch is the only source of error which would not be eliminated by a proper 
 use of the instrument, and in the taking of a number of observations, as is always the 
 case in meteorology. 
 
 It is curious that a barometer maker, named Assier-Perricat, of Paris, as long ago as 
 1802, practised and advocated the method of ensuring the accuracy of barometers by 
 comparison. (Assier^Perricat, Nouveau Traite sur 1' Invention des Barometres, etc.) 
 
 It is important to be able easily to detect the presence of any air which might by 
 accident get into the upper part of the barometer tube, where it would falsify the reading 
 by a minute direct pressure, and probably also by increasing the capillary action. There 
 happens to be a ready and perfect test as follows : Incline the barometer so that the 
 mercury may run up and strike the sealed end of the tube ; if the sound be sharp and 
 metallic, repeat the experiment several times, each time more gently. If the least 
 trace of air be present, the sound will at last become soft and puffy ; if, on the con- 
 trary, the vacuum be perfect, the sound will always remain beautifully clear and 
 distinctly metallic. 
 
 If air be thus detected, uncover and examine the end of the tube, to see how large 
 a bubble remains when the barometer is laid flat. Also invert the instrument and tap 
 it, as sharply as is safe, near the bubble, which may sometimes be thus dislodged and 
 eliminated. We do not think that a minute quantity of air can sensibly affect the 
 reading of the barometer for ordinary purposes, but if there be more, the instrument 
 must certainly be disused until refilled by the maker. If important observations have 
 been made with a barometer containing air, they may be corrected, if the barometer be 
 compared with a true one before its condition is altered. The simple difference of 
 readings will be an. approximate correction, but the exact correction is 
 
 in which e 2 and e 3 are the errors of the readings k^ and h z at different points of the 
 scale, as determined by comparison, and h is the reading to be corrected. 
 
 If we suppose a bubble of air of ~ of an inch diameter at the atmospheric pressure 
 to eater the vacuous space of the Fortin barometer, described above, the depressing 
 effect on the mercurial column may, by a simple calculation, be shown not to exceed 
 10 ooo f an inch, apart, however, from any influence on the capillarity, a point probably 
 of much greater importance than the direct effect. 
 
 DIRECTIONS FOB TAKING AN OBSERVATION OF THE BAROMETER. 
 
 1. Read and record the attached thermometer, making a correction for index error 
 if necessary (see THERMOMETER). 
 
 2. Adjust the mercury below to exact contact with the fiducial point. 
 
 3. Slightly tap the tube near the upper end of the column, and adjust the edge of 
 the vernier to exact tangential contact, the line of vision being horizontal. 
 
 4. Eecord the reading and work out the correct height as soon as convenient after- 
 wards, as shown in the following example, which comprises all the corrections ever 
 required : 
 
 Inches. 
 
 Attached thermometer . . 58'3 F. Barometer reading . . 29-964 
 
 Data. Neutral point . . 28-861 Correction for capacity . + -033 
 
 Capacity . ^ capillarity + -007 
 Diameter of the tube . -4 inch 
 Index error to K. 0. 
 
 Standard (apart from temperature --080 
 
 capillarity) . - -014 inch index error -.-014 
 
 True height of the barometer 29-910 
 
 LL 2 
 
516 
 
 BAROMETER. 
 
 When many observations of one barometer have to be made, much labour will be 
 saved by combining all these corrections into a special table, one reference to which 
 furnishes the required correction. In important observations or comparisons, the ad- 
 justments and vernier readings should be made with a pocket lens. 
 
 It is much to be desired that the English should adopt the metre scale for the baro- 
 meter, which is used all over the Continent; but although this may at once be done in 
 chemical matters, it seems almost impossible at present in meteorology. For the easy 
 reduction of the barometer scale from millimetres into English inches and vice versa, 
 we give the following tables. Negretti's portable barometer may be hadVith both 
 millimetre and inch scales attached. 
 
 Milli- 
 metres. 
 
 Inches. 
 
 Milli- 
 metres. 
 
 Inches. 
 
 Milli- 
 metres. 
 
 Inches. 
 
 700 
 
 27-560 
 
 751 
 
 29-567 
 
 762 
 
 30-000 
 
 705 
 
 27756 
 
 752 
 
 29-607 
 
 763 
 
 30-040 
 
 710 
 
 27-953 
 
 753 
 
 29-646 
 
 764 
 
 30-079 
 
 715 
 
 28-150 
 
 754 
 
 29-685 
 
 765 
 
 30-119 
 
 720 
 
 28-347 
 
 755 
 
 29-725 
 
 766 
 
 30-158 
 
 725 
 
 28-544 
 
 756 
 
 29-764 
 
 767 
 
 30-197 
 
 730 
 
 28-741 
 
 757 
 
 29-804 
 
 768 
 
 30-237 
 
 735 
 
 28-938 
 
 758 
 
 29-843 
 
 769 
 
 30-276 
 
 740 
 
 29-134 
 
 759 
 
 29-882 
 
 770 
 
 . 30-315 
 
 745 
 
 29-331 
 
 760 
 
 29-922 
 
 771 
 
 30-355 
 
 750 
 
 29-528 
 
 761 
 
 29-961 
 
 772 
 
 30-384 
 
 1 millimetre = 0-03937 inch 1 inch = 25-39954 millimetres 
 
 0-1 = 0-00394 0-1 = 2-53995 
 
 0-01 = 0-00039 0-01 = 0-25400 
 
 0-001 = 0-02540 
 
 USES OF THE BAROMETER. The chemist requires to know the atmospheric pres- 
 sure when very accurate weighings are made of light bodies, in order that the weight 
 of the air they displace may be allowed for. On this subject, see Bessel's formulae in 
 the article SPECIFIC GRAVITY. Secondly, gases are usually weighed or measured, sub- 
 ject to the atmospheric pressure, and vary directly in density and.' inversely in volume 
 with the pressure. Hence the atmospheric pressure must always be observed at the 
 moment, in order that the weight or measure may be reduced, by a simple calculation, to 
 what it would be at some standard pressure, which in England is 30*000 inches, and 
 
 QA'AAfi 
 on the Continent 760 millimetres or 29*922 inches. Now - x 100 = 100-261 
 
 2t&*u2i2i 
 
 or 100 cubic inches of gas at the English standard pressure are equal to 100-261 cubic 
 inches at the French standard pressure. It happens, however, that the English adopt 
 60 F. and the French 32 F., as the standard temperatures in these matters, and 
 allowing for the expansion of mercury between these points, 29-922 inches become 
 30-006. Hence the true equivalent volume on the continental standard for 100 cubic 
 
 inches of gas at 30-000 inch, 60 F., is 
 
 100 = 99-98 cubic inches, the differ- 
 
 30-006 
 ence being so trifling that it may almost always be neglected. 
 
 DETERMINATION OF ALTITUDES. Since the barometer measures the weight of the 
 superincumbent air, the higher we rise in the atmosphere the lower the barometer must 
 stand. At the surface of the earth, the barometer changes nearly -001 inch for every 
 foot in the change of altitude ; but more exactly, the change of elevation correspond- 
 ing to '001 inch of the barometer, is : 
 
 At temperature of 30 0'865 foot 
 
 ,,40 0-883 
 
 50 . . . . . 0-900 
 
 60 . . . . . 0-918 
 
 ,,70 0-936 
 
 ,,80 0-954 
 
 The difference of level ( = x feet) of two barometers may be calculated by the follow- 
 ing formula : 
 
 x = 60345-7 x \ 1 + 0-002837 cos 2 lat. j x jl T H 
 
BAROMETER BARYTIC FLUORSPAR. 517 
 
 In which B and b are the simultaneous corrected heights of the barometers at the 
 higher and lower stations, and 2\ t the numbers of degrees Fahr. above 32, at which, 
 the thermometers stand. (Biot, Trait6 de Physique, i. 100.) 
 
 If the height does not much exceed 3000 feet, the following more simple formula 
 may be used : 
 
 xi^**{i+ r " 
 
 In meteorological observations, it is necessary to know the height of the barometer 
 above the mean sea level, and to reduce the average results to that level accordingly, in 
 order that they may be comparable with observations made at other places, and reduced 
 in a similar manner. 
 
 METEOROLOGY. The chief use of the barometer is of course in meteorology, since 
 changes of pressure in the atmosphere are the immediate cause of all winds. These 
 changes are extremely complicated and interesting : for besides the irregular fluctua- 
 tions, and extraordinary disturbances during storms, there is an average change, ac- 
 cording to the season, and a semidiurnal oscillation, probably due to a kind of 
 atmospheric tide, caused by the expansion of the atmosphere, where it is heated by 
 the sun's rays (Phil. Mag. [4] xvii. 313). In keeping a register of the barometer, it 
 should be observed every day at 9 A. M., the time of the daily maximum, and at 3 p. M., 
 the time of daily minimum, or else at noon, when the pressure is near the mean. 
 
 The nightly maximum is about 9 P.M., the nightly mininum about 4 A.M. Almost 
 every climate, however, is characterised by special laws of barometric fluctuation. 
 
 ANEROID BAROMETER, (a, priv. vypos, liquid). The essential part of this beautiful 
 instrument is a small round metal box, exhausted of air, and with a thin circularly 
 fluted lid, which the weight of the atmosphere more or less tends to press in. A 
 complicated system of levers, causes an index, revolving over a dial, to mark the 
 slightest movements of this metal lid. (Vidi, Compt. rend. xxiv. 275; Belville's 
 Manual of the Mercurial and Aneroid Barometers.) 
 
 BOURDON'S METALLIC BAROMETER also consists of a vacuous metal box, but it is in 
 the form of a flat tube bent almost into a circle. The two ends of the tube approach 
 or recede as the atmospheric pressure increases or diminishes. 
 
 These metallic barometers are very sensitive and excellent as weather glasses, and 
 they should be carried at sea or on exploring expeditions as a last resource in case the 
 mercurial barometers, as often happens, become disordered. But they afford no inde- 
 pendent measure of pressure, and are so much affected by variations of temperature as 
 to be unsuitable for scientific use. The writer, however, has used an aneroid baro- 
 meter with some success, and obtained an approximate correction for temperature by 
 simply warming the instrument on various occasions, and noting the average change 
 of reading (= -0065 inch per degree F.) thus caused. An adjusting screw will be 
 found at the back of the aneroid barometer, by which its reading may be made to 
 agree at some one point and temperature with that of a mercurial barometer. 
 
 For a description of Macworth's " Underground barometer," see Ure's Dictionary 
 of Arts, Manufactures, and Mines, i. 255.) W. S. J. 
 
 BARRAS. The resinous incrustation in the wounds made in fir-trees. 
 
 BARSOWITE. A silicate of calcium and aluminium found near the river Bar- 
 sowka in the Ural, in compact white masses or fine-grained aggregations, having a 
 distinct cleavage in one direction. The granular variety has a faint mother-of-pearl 
 lustre : the compact variety is dull and translucent on the edges. Sp. gr. 2740 to 
 2752. Hardness 5'5 to 6'0. Before the blowpipe, it melts with difficulty to a tume- 
 fied glass on the edges : with borax, slowly and quietly to a transparent colourless 
 glass ; likewise with phosphorus-salt, with separation of silica, the glass becoming 
 opalescent on cooling if the proportion of the mineral is considerable. With an equal 
 weight of carbonate of sodium, it melts to a tumefied glass, which with a larger 
 quantity of soda, becomes snow-white and infusible. With solution of cobalt, it 
 becomes blue on ignition. The powder is easily decomposed by hydrochloric acid, 
 forming a thick jelly. According to Varrentrapp's analysis, it contains 3(2Ca 2 O.Si0 3 ). 
 (4Al'0 3 .3Si0 2 ) a small quantitiy of the lime being replaced by magnesia. (Handw 
 d. Chem. 2" Aufl. ii. 679.) 
 
 BARWOOD or C AIV1WOOD. A red dye-wood, the colouring matter of which 
 appears to be identical with santolin (Preisser und Girardin, Ann. Ch. Phara. lii. 
 376.) See also Urcs Dictionary of Arts, Manufactures and Mines, i, 255.) 
 
 BARYTA. See BARIUM, OXIDES OF. 
 
 BARYTES, BARYTXNE, or BAROSEZ.ENTTE. See HuAVY SPAB. 
 
 BARYTIC FLUORSPAR. A mixture of about equal parts of sulphate of barium 
 
 L L 3 
 
518 BARYTO-CALCITE BASALT. 
 
 and fluorspar, occurring on the slaty limestone of Derbyshire, where it forms a bed 
 about an inch thick. 
 
 BAHYTO-CALCITE, BaCaCO 9 or BaO.CO* + CaO.CO 1 *; a mineral found in 
 Cumberland, of a slightly yellowish-brown tinge, translucent, with a waxy lustre, and 
 sp. gr. 3-66. It contains cavities which are lined with crystals having the form of oblique 
 rhombic prisms. The external surface is coated with sulphate of barium. (Brooke. 
 Ann. Phil. N.S. viii. 114.) 
 
 The name baryto-calcite was also given by Thomson to a laminated mineral con- 
 taining 71-9 p. c. sulphate of barium and 2S'l sulphate of calcium, found between 
 Leeds and Harrogate in Yorkshire; also by Johnston to Alstonite, which is of the 
 same composition but different crystalline form. 
 
 BARYTO-CCEItESTICT. This name is given to two minerals, both consisting 
 of sulphate of barium and sulphate of strontium (coelestin), one occurring near Kings- 
 town in Canada, the other in the Binnenthal in Switzerland. The Swiss mineral forms 
 orthorhombic crystals, containing, according to Waltershausen (Pogg. Ann. xciv. 
 134), 87'S p.c. sulphate of barium and 9'1 sulphate of strontium. The Canadian mine- 
 ral occurs in crystalline masses, containing, according to Thomson, Ba'^Sr'.SSO 4 . 
 Allied to this is a mineral from the chalk marl of Moen, containing 40 p.c. Sr 2 S0 4 , 
 28-3 Ba 2 S0 4 , 15'5 Ca 2 S0 4 , 13-5 Ca 2 C0 3 , and 2'5 water. 
 
 BARYTOPHYXiXiXTE. Syn. with CKLOKITOIDE. 
 
 B ASAXiT. A rock of volcanic origin, occurring in amorphous masses, columnar, 
 amygdaloida], and vesicular. Its colours are greyish-black, ash-grey, and raven-black. 
 Massive, with dull lustre and granular structure. Fracture uneven or conchoidal. 
 Concretions columnar, globular, or tabular. It is opaque, yields to the knife, but is 
 not easily frangible. Streak light ash-grey. Sp. gr. 3. Melts into a black glass and 
 recovers its granular structure by slow cooling. It is found in beds and veins in 
 granite and mica slate, the old red sandstone, and coal formations. It is distri- 
 buted over the whole world, and is met with in great variety in Scotland. 
 
 The most remarkable variety of basalt is the columnar, which forms immense 
 masses, composed of columns thirty, forty, or more feet in height, and of enormous 
 thickness ; those at Fairhead are two hundred and fifty feet high. These constitute 
 some of the most astonishing scenes in nature, for the immensity and regularity of 
 their parts. The coast of Antrim in Ireland, for the space of three miles in length, 
 exhibits a very magnificent variety of columnar cliffs ; and the Giant's Causeway 
 consists of a point of that coast formed of similar columns, and projecting into the sea 
 upon a descent for several hundred feet. These columns are, for the most part, 
 hexagonal, and fit very accurately together; but most frequently do not adhere 
 together, though water cannot penetrate between them. Another very remarkable 
 formation of columnar basalt is the island of Staffa on the west coast of Scotland. 
 The most extensive mass of basalt yet observed is that discovered by Colonel Sykes 
 in the Deccan, where it occupies a surface of many thousand square miles. 
 
 Basalt is not a mineral of definite constitution, but a mixture of several minerals, 
 generally of labradorite, augite, olivine, magnetic iron ore, and a zeolite. These 
 minerals may however be replaced by others, namely labradorite by other varieties of 
 felspar, and augite by amphibole : the zeolitic portion also varies greatly in compo- 
 sition. Some of the constituents of basalt viz. the olivine, the magnetic iron ore and 
 the zeolite are decomposible by hydrochloric or sulphuric acid ; the rest for the most 
 part resist the action of acids ; but the analytical results obtained by this mode of 
 treatment are not very definite, inasmuch as the action of the acid varies with its 
 strength, with the state of aggregation of the basalt, and with the nature of the 
 individual minerals of which it is composed. The constituents of basalt, are silica 
 (about 50 per cent.) alumina, protoxide of iron, lime, magnesia, potash, soda and 
 water, the proportions of which differ considerably in the several varieties of basalt, 
 as shown by the numerous analyses which have been made of it. 
 
 Basalt when calcined and pulverised, is said to be a good substitute for pozzolana 
 in the composition of mortar, giving it the property of hardening under water. Wine 
 bottles have likewise been manufactured with it, but there appears to be some nicety 
 required in the management to ensure success. A mixture of 1 pt. basalt, 2 pts. 
 broken ^glass, 2 soda, 1 wood-ash, and ^ peroxide of manganese, has also been used 
 for similar purposes. 
 
 BASAXiTIC HORNBXiERTDE usually occurs in opaque six-sided crystals, which 
 sometimes act on the magnetic needle. It is imbedded in basalt or grauwacke. 
 Colour velvet-black. Lustre vitreous. Scratches glass. Melts with difficulty to a black 
 glass. Contains 47 per cent, silica, 26 alumina, 8 lime, 2 magnesia, 15 iron, and 0-5 
 
BASANITE BASTITE. 519 
 
 
 
 water. It is found in the basalt of Arthur's Seat, in that of Fifeshire, and in the Isles 
 of Mull, Canna, Eigg, and Skye ; also in the basaltic and floetz traps of England, 
 Ireland, Saxony, Bohemia, Silesia, Bavaria, Hungary, Spain, Italy, and France. U. 
 
 BASANZTE. See JASPEE. BASANOMEI.AOTE. See ILMENITE. 
 
 33 ASE. This term is the correlative of Aero, and denotes the electropositive consti- 
 tuent of a salt. Its signification varies, however, to a certain extent, according to the 
 view which is taken of the constitution of salts. In the dualistic system, which re- 
 gards salts as formed by the union of two binary compounds of the first order, e.g. 
 sulphate of copper = Cu 2 O.S0 3 ; sulpharsenate of potassium = 3K'-S.As 2 S 5 : hydro- 
 chlorate of ammonia = NH 3 .HC1 ; nitrate of ethylamine = NH 2 (C 2 H 5 ).HN0 3 , &c. ; 
 the base is the electropositive oxide, sulphide, selenide, or alkaloid, which unites with 
 the electronegative oxide, sulphide, &c., or hydracid ; but in the unitary system, in 
 which the salts of any acid are regarded as formed on the same type as the acid (or 
 hydrogen-salt) itself, the base must be understood as the metal or other electropositive 
 radicle by which the hydrogen of the acid is replaced : thus in the salts above-men- 
 tioned, regarded as Cu 2 SO l , K 3 AsS 4 , NH 4 C1, NH 3 (C 2 H 5 ).N0 3 , the bases are the radicles 
 Cu, K, NH 1 , NH 3 (C 2 H 5 ). (See ALKALIS, ALKALOIDS, AMINES, AMMONIUM-BASES, 
 OXIDES, EADICLES.) 
 
 EASICERINE. See HYDROCEBITE. 
 
 B ASXCXT1T. The power of an acid to unite with one or more atoms of base. See 
 ACIDS, p. 46. 
 
 BASIXiICUIVX, OXXi OP. The leaves of the Ocymum basilicum, a plant belong- 
 ing to the labiate order, yield by distillation with water, an essential oil, which after 
 a while deposits prismatic crystals, having the character and composition of hydrate 
 of turpentine, C 10 H^O :J = C 10 II 16 .3H 2 (Dumas and Peligot). The oil itself has not 
 been examined. 
 
 BASSZA XiATXFGXiXA. The seeds of this plant, which grows on the Hima- 
 layas, yield by pressure a yellowish oil, which gradually becomes colourless on expo- 
 sure to light, has a faint odour, a density of 0'958, and a buttery consistence at 
 ordinary temperatures ; melts at 27 to 30 C. ; dissolves sparingly in anhydrous 
 alcohol, scarcely at all in spirit of ordinary strength, readily in ether. By saponifica- 
 tion it yields, besides oleic acid and glycerin, two fatty acids, one which has not been 
 obtained pure, but appears to have the composition C 15 H 30 8 ; the other, originally 
 supposed to be a peculiar acid, and called bassic acid, is identical in composition and 
 properties with stearic acid, C 18 H 36 2 . (Hardwicke, Chem. Soc. Qu. J. ii. 231.) 
 
 BASSORXRT. The principal constituent of Gummi bassorce, Cr. Toritonense, or 
 Cr. Kutera, a gum obtained from various species of acacia. This gum contains only 
 about 5'6 per cent, of matter soluble in water (arabin), while the larger proportion, 
 which is the bassorin, merely swells up in water. (See GUM.) 
 
 BASTARD CIiOVER. Trifolium hybridum. 100 pts. of the fresh flowering 
 plant yield 2*44 pts. of ash ; 100 pts. of the dry plant 8'1 pts. of ash. The ash con- 
 tains in 100 pts. 19-9 potash, 57 soda, 18'4 lime, 3-1 magnesia, 5'6 alumina (?), 3'9 
 sesquioxide of iron, 1-8 protoxide of manganese (?), 35 - l silica, T4 sulphuric anhydride, 
 4*5 phosphoric anhydride, 0'6 chlorine. (Sprengel, J. pr. Chem. x. 56.) 
 
 BASTITE. A mineral found at Basti in the Harz, and forming imperfectly 
 defined individual crystals intergrown with serpentine. It cleaves very easily in one 
 direction, less easily in another, making an angle of 87 with the first ; there are also 
 two imperfect cleavage-planes in the direction of the longitudinal and lateral faces. 
 Fracture, uneven and splintery. Colour, leek to olive green, passing into yellow and 
 brown. It has a metallic, glittering, nacreous lustre on the cleavage-faces ; translucent 
 on the edges. Specific gravity 2 -6 to 2'8. Hardness 3-5 to 4'0. Gives off water when 
 heated, and before the blowpipe becomes pinchbeck-brown and magnetic ; it then 
 splinters, melting to a brown glass on the edges. With borax and phosphorus-salt, 
 it gives the reactions of iron and chromium, and with the latter a skeleton of silica. 
 It is imperfectly decomposed by hydrochloric, completely by sulphuric acid. Its 
 composition is nearly represented by the formula 4Mg 2 H'O s . 3(Mg 4 or Fe 4 )Si 3 8 
 which, if the hydrogen be regarded as basic, may be reduced to the general form 
 M 3B Si 9 3fi , that is to say to the formula of an orthosilicate M 4 Si0 4 . Hermann 
 regards the mineral as crystallised serpentine somewhat altered in composition by ad- 
 mixture of foreign minerals ; but its form indicates rather a relation to the augite 
 family. (Handw. d. Chem. i. 756.) 
 
 BASYXf. Graham's name for the metal or other electropositive constituent of a 
 Bait (Elements of Chemistry, 2nd ed. i. 186). 
 
 L L 4 
 
520 
 
 BATATAS BATH. 
 
 BATATAS EDUXXS. Sometimes called Convolvulus batatas or Spanish 
 potato, a plant said to be indigenous in India, but extensively cultivated in America, 
 and sometimes also in the south of Europe. The tubers resemble those of the potato, 
 but have a sweeter taste. According to T. J. Herapath (Chem. Soc. Qu. J. iii. 
 194), they contain, in the fresh state, 66'7 per cent, water and other volatile matter, 
 31'8 vegetable matter, and I'd inorganic matter. The ash contains in 100 pts. : 
 
 (a.) Soluble in water. 87 CO 2 , 7'1 SO 3 , 0-9 P 2 5 , 29'3 K 2 0, 12'4 KC1, and 11-4 
 NaCL 
 
 (6.) Insoluble. 6-2 CO 2 , 7'1 P 8 5 , 12-0 Ca 2 0, 1-4 Mg 2 0, 1-3 Fe 4 3 , 2-1 SiO 2 , with 
 traces of sulphuric acid and alumina. 
 
 According to Henry (J. Pharm. xi. 223) the tubers contain in 100 pts. 13'3 starch, 
 0'9 albumin, 3'3 sugar, 1*1 fat insoluble in ether, 6'8 woody fibre, 1'4 malic acid, acid 
 phosphates, chloride of potassium, &c., and 73'1 water, also 0-05 of a volatile poisonous 
 matter. 
 
 BATH. The heat communicated from lamps and fires is subject to variation from 
 many circumstances ; and this variation not only influences the results of operations, 
 but often endangers the vessels, especially if they are made of glass. To obviate these 
 sudden changes of temperature, and at the same time to afford means of observing and 
 regulating the degree of heat imparted, the vessel containing the substance operated 
 upon is immersed in another containing water, oil, fusible metal, air, or other medium, 
 which receives the heat directly from the source. The sand-bath and water-batli are 
 most commonly used, the latter for maintaining a substance for any length of time at 
 the constant temperature of 100 C., the former for higher temperatures, particularly 
 when the exact observation of the temperature is not an object. In using the water- 
 bath, the vessel to be heated may, according to convenience, be either immersed in 
 the water or so placed above the vessel that its lower surface may be in contact with 
 the steam. A ready method of constructing a water-bath for small operations is to 
 place the basin containing the substance to be heated on the top of another of equal 
 size, containing water and supported over a gas lamp. 
 
 The temperature of the water-bath may be raised above 100 C., by dissolving certain 
 salts in the water. A saturated solution of common salt boils at a temperature of 7'5 C. 
 or 13 3 F., above the boiling point of water ; and by using a solution of chloride of 
 calcium, a bath of any temperature between 100 and 125 C. or 212 and 252 F. 
 may be conveniently obtained. 
 
 Liquid baths of higher temperature are obtained by the use of linseed oil or fusible 
 metal heated in cast-iron pots. The oil-bath may be used for temperatures up to about 
 300 C., but it is dirty, and exhales an extremely unpleasant odour when strongly heated. 
 Fusible metal is much cleaner and more pleasant to use, but its weight is an incon- 
 
 Fiff. 94. 
 
 Fig. 95. 
 
 venience where a large bath is required. A thermometer immersed in the liquid, as 
 near the middle as possible, serves to indicate the temperature. The oil-bath is much 
 used in the determination of vapour-densities by Dumas's method, also for heating 
 Tolatile substances or mixtures in sealed tubes, so as to subject them to a higher tern- 
 
BATH. 
 
 521 
 
 perature than that to which they could be exposed under the ordinary atmospheric 
 pressure. The danger of explosion attending this operation may be obviated by 
 enclosing the sealed glass tube in a strong tube of wrought iron, haying a massive 
 screw cap. 
 
 The air-bath is very convenient for many purposes, especially for desiccation. An 
 air-bath may be extemporaneously constructed by placing an empty basin over a lamp, 
 and another basin containing the substance to be dried on the top of it. The upper 
 vessel is then heated by the air in the intervening space. A more convenient apparatus, 
 which also serves to indicate the temperature, consists of a cylindrical copper vessel A, 
 fig. 94, the cover of which is movable and has two apertures, the middle serving for 
 the escape of vapour and the lateral one for the insertion of the thermometer. The 
 vessel to be heated rests on a ring within the box, supported by a tripod. A larger 
 air-bath serving to heat several small vessels at once is represented in fig. 95. Air- 
 baths are sometimes surrounded with a jacket to hold water or oil. When water is 
 used, the temperature of course cannot exceed 100 C. "When oil is used, the tempera- 
 ture is indicated by a thermometer having its bulb immersed in the liquid. 
 
 High-pressure baths. The danger of explosion in heating volatile liquids in sealed 
 tubes is greatly diminished, when the tubes are at the same time subjected to a pres- 
 sure from without. This may be effected by enclosing the tube containing the volatile 
 liquid in a wider glass tube containing a less volatile liquid, and likewise sealed ; the 
 whole is then heated in an oil- or air-bath. In this manner, alcohol or ether may be 
 
 heated to 360 C., the outer tube containing oil of turpentine (Berthelot). Greater 
 security is obtained by enclosing the glass tube in a wrought, iron tube, with a 
 screw-cap, or by the use of a Papin's digester, or better, by the following apparatus 
 invented by Frankland (Ann. Ch. Pharm. xcv. 30). 
 
 A A (fig. 96) is an iron cylinder 18| inches long, 3 inches internal diameter, 
 inch thick in the side, and welded in one piece by the steam hammer. This cylinder 
 
522 BATH-METAL BAULITE. 
 
 has a flanch, B B, 1| inch broad, f inch thick, turned true on the upper surface, and 
 having an internal annulus* sunk ^th of an inch below the level of the surrounding sur- 
 face. The cap C C, which is of the same diameter and thickness as the flanch, has a 
 projecting face | inch deep which fits exactly into the mouth of the cylinder. Within this 
 projection the cap is pierced with two apertures, into one of which is fitted a cast-iron tube 
 d, 6 inches long and | inch in external diameter, filled with mercury and destined to 
 receive a thermometer. The other aperture is bouched with brass, and serves as the 
 bed of the safety-valve, which consists of brass wire | inch thick, somewhat flattened on 
 two sides, and furnished with a head accurately ground to the surface of the cap. The 
 valve is loaded in the usual way with a lever / and weight g. The cap and flanch 
 are fastened together by four screw-bolts, which are inserted from below and tightened 
 by a lever-key, and the pressure thus exerted acts upon a lead washer | inch thick, 
 placed in the annular depression of the flanch. In this manner the apparatus may be 
 made capable of bearing a pressure of 100 atmospheres without allowing any escape 
 of gas. The cylinder A is about two-thirds filled with water, and the glass tube con- 
 taining the volatile liquid is enclosed in it. In this manner, tubes of considerable width 
 may be heated without danger of explosion. 
 
 The apparatus is heated in a gas-furnace (fig. 97). A A A A is a massive frame of 
 wrought-iron, within which is fixed a cylinder B B, cf tin plate, closed at bottom and 
 open at top to receive the apparatus above described, c is a regulator for the admis- 
 sion of air. The gas-burner is a copper tube e, | inch wide and pierced with 18 or 
 20 apertures. To prevent loss of heat by radiation, the whole apparatus is enclosed 
 in a cylinder B' B', of polished tin plate, separated from the inner cylinder by a space 
 about | an inch wide. The products of combustion escape by the apertures D D. 
 
 BATH-METAL An alloy of copper and zinc containing a larger proportion 
 of zinc than ordinary brass, and usually prepared by melting brass with zinc. 
 
 B ATRAC KITE. A mineral found on the Eizomberg in the Tyrol, generally massive, 
 with a granular structure, rarely crystalline. It contains according to C. E a mm els- 
 berg (Pogg. Ann. li. 466), 37'69 silica, 35-45 lime, 2179 magnesia, 2*99 protoxide of 
 iron, and T27 water. Colour varying from light greenish-grey, like that of a frog 
 ), to white ; translucent with waxy l 
 
 lustre. Specific gravity 3'0 to 3-1. 
 
 Hardness = 5'0. Melts before the bio wpipe, assuming a pale red colour with solution 
 of cobalt ; is but slightly attacked by acids. The water appears to be xinessential, 
 and the composition of the mineral approaches to that of Monticellite. (Handw. d. Chem. 
 ii. 757.) 
 
 BATRACHOXiEXC ACID. An acid said to be contained, together with stearic 
 acid, glycerin, and a peculiar yellow fat, in the oil obtained by pressure from the 
 epiploon of the water salamander. (Eossignon, Compt. rend. xiii. 929.) 
 
 BATTDXSSERXTE. A dense variety of magnesite containing silica, found near 
 Baudissero in Piedmont. As the amount of water contained in it is very variable, 
 F. v. Kobell and Neumann regard it as a compact hydromagnesite intimately mixed 
 with silica. 
 
 BAUZiXTE, or Krablite. A mineral found on the Krabla in Iceland, and likewise 
 on the Baulaberg, either in short prismatic crystals belonging to the triclinic or doubly 
 oblique prismatic system, or in crystal! o-granular masses. Cleavage in two directions 
 at right angles to each other. Fracture uneven and conchoidal. Colourless, with 
 glassy lustre; transparent or translucent. Specific gravity 2'5 to 27. Hardness 5-5 
 to 6*0. In the following table, a is the analysis of a specimen of baulite resembling 
 pearlstone, from the Baulaberg, by Forchammer (Ann. Min. viii. 644) ; b is that of 
 a crystallo-granular variety of baulite, ejected by the volcano of Viti in Iceland, mixed 
 with quartz-crystals and a black needle-shaped mineral, also byForchhammer (Ber- 
 zelius's Jahresb. xxiii. 261) : c is Grenth's analysis (J. pr. Chem. Ixvi. 93), of crystal- 
 lised baulite from the Krabla : 
 
 SiO 2 Al'O 3 Fe'O 3 Fe 2 Mn<0 3 Ca 2 Mg 2 K 2 Na 2 Cl, H 2 
 
 a. 74-38 13-78 1-94 1-19 0-85 0-58 2-63 3-57 0-12 2-08 
 
 b. 76-65 11-57 0-63 0'05 0'20 3'26 373 
 
 c. 80-23 11-34 trace 1-46 trace 4-92 2'26 
 
 These analyses agree sufficiently well with the formula (M 2 0.3Si0 2 ).(Al 4 3 .6Si0 8 ), 
 which (if al = |A1) may be reduced to (M 2 aZ 6 )8i 9 M or 2K 4 Si0 4 .7SiO ;2 , the formula 
 of an orthosilicate with \ at. silica ; but it is probable, as Bunsen supposes, that the 
 mineral is intimately mixed with orthoclase, Before the blowpipe, baulite is fusible 
 in very thin splinters ; with borax and phosphorus-salt it yields clear glasses, a skeleton 
 of silica floating in the latter. It is insoluble hi hydrochloric acid. (Handw. d. Chem. 
 ii. 758.) 
 
BAVALITE-BEAN. 
 
 523 
 
 SAVAIcITE. See BARALITE. 
 BAY-SAXiT. See SODIUM, CHLORIDE OF. 
 
 A gum-resin of which there are two varieties, African and Indian. 
 African bdellium is derived, according to Perrotet, from a shrub indigenous in Sene- 
 gambia, the Hcnddotia africana (Gruillem andPerr); Balsamadendron africanum 
 (Arnott); Amyrks Nicattout (Adanson), belonging to the amyredaceous order. It 
 forms irregular, translucent masses, of a yellowish, reddish, or brownish colour, accord- 
 ing to age; unctuous to the touch, brittle, but soon softening, and growing tough 
 between the fingers. Specific gravity 1-371. It has a bitterish taste, and a moderately 
 strong balsamic odour, not unlike that of myrrh. It does not easily take fire, and 
 when set on fire soon goes out : in burning it gives off a balsamic odour, and sputters 
 a-little, owing to the presence of moisture. Alcohol dissolves about | of it, forming a 
 golden-yellow tincture, from which water throws down a yellowish-white resin, and 
 nitric acid a sulphur-yellow resin. Potash dissolves it completely. By dry distillation 
 it yields ammonia, together with other products. According to Pelletier (Ann. Ch. 
 Phys. [2] Ixxx. 38), it contains 59 per cent, resin, 9'2 gum, 30'6 vegetable mucus, and 
 1-2 volatile oils (and loss). 
 
 The resin is transparent, but becomes white and opaque by boiling with water ; 
 melts between 58 and 60 C. According to Johnston (J. pr. Chem. xxvi. 145), it is 
 C l H 31 5 . The gum is yellowish-grey, and when treated with nitric acid, yields malic 
 but no mucic acid. The vegetable mucus is also yellowish-grey, swells up with water, 
 coagulates with alcohol, and is converted by nitric acid into a thin liquid. The volatile 
 oil is heavier than water. 
 
 Indian bdellium is said to be obtained from Balsamodendron MuJcal (Hooker), 
 also an amyredaceous tree, growing in Scinde. It forms irregular, greenish-brown, or 
 blackish masses, having a strong odour, and sharp bitter taste like myrrh. It becomes 
 sticky between the fingers. 
 
 SEAN. Two species of bean are commonly cultivated in Europe, viz. 1. Faba 
 vulgaris, or Vicia Faba, the common field or garden bean (Feldbohne, grosse Bohne, 
 Saubohne), the most common garden varieties of which are the Windsor broad bean, 
 the Toker, the long-pod, and the Mazagan, while for field cultivation, the Heligoland, 
 or tick-bean, and the common horse-bean, are preferred as being more hardy. 
 2. Phaseolus vulgaris, the French, haricot, or kidney-bean, innumerable varieties of 
 which are cultivated, some dwarf, others climbing. The scarlet-runner, Phaseolus 
 multiflorus is closely allied to this species. 
 
 The seeds of these several species and varieties differ but little in chemical com- 
 position, as the following tables will show; but they are all remarkable for the large 
 amount of nitrogenous matter (legumin) and phosphoric acid which they contain. 
 
 TABLE A. Composition in 100 parts of various kinds of Bean. 
 
 
 Legumin, 
 &c. 
 
 Sugar. 
 
 Gum. 
 
 Starch. 
 
 Fat. 
 
 Pectin 
 substances. 
 
 Woody 
 fibre. 
 
 Ash. 
 
 Water. 
 
 1. Field-bean (air-dried] 
 
 24-2 
 
 
 44-2 
 
 1-4 
 
 
 12-6 
 
 3-6 
 
 14-0 
 
 2. 
 
 23-3 
 
 2-0 
 
 4-5 
 
 36-0 
 
 2-0 
 
 4-0 
 
 10-0 
 
 3-6 
 
 14-8 
 
 3 Haricot-bean 
 
 250 
 
 0-3 
 
 4-0 
 
 38-0 
 
 3-0 
 
 12-0 
 
 3-7 
 
 14-0 
 
 4. old Irish (untried) 
 
 247 
 
 4-6 
 
 3G-4 
 
 24 
 
 17-6* 
 
 1-8 
 
 12-8 
 
 5. Egyptian (undricd) 
 
 24-6 
 
 6-5 
 
 31-5 
 
 2-8 
 
 18-8 
 
 
 10-8 
 
 G. common white (air- 
 
 
 
 
 
 1-8 
 
 
 dried) 
 
 22-8 
 
 45-4 
 
 2-7 
 
 6-2 f 
 
 3-6 
 
 19'3 
 
 1. Poggiale (J. Pharm. [3] xxx. 180). The shells amounted to 15 per cent, of 
 the weight of the entire pods, and contained neither legumin nor starch. 2. Mean of 
 earlier analyses by Braconnot, Horsford, and Rrocker. 3. Mean of earlier analyses by 
 Einhof, Boussingault, Horsford, and Krocker. 4, 5. Poison (Chem. Gaz. 1855, 
 p. 211). 6. Poggiale (loc. tit.} The shells amounted to 7'5 per cent, of the weight 
 of the entire pods, contained very little starch, 0'2 per cent, fat, 6*5 nitrogenous 
 matter, and 5'8 ash. 
 
 Ward and Eggar (Jahresber. d. Chem. 1849, p. 708), obtained from several 
 varieties of fresh beans grown on various soils : 2-4 to 3 -6 per cent, nitrogen, 1*2 to 
 1-7 per cent, fat, and 11-0 to 17'0 per cent, water. Way and Ogston obtained from 
 the same varieties of bean (Heligoland and Mazagan), grown on various soils, in 
 100 pts. of the fresh seeds : 8-1 to 17'0 per cent, water, and in 1000 pts. of the dried 
 seeds of five varieties, 2-5 to 2'9 per cent, sulphur, in a sixth kind, 4'6 per cent 
 sulphur. 
 
 * Cellulose and Shells. -f Cellulose. 
 
524 
 
 BEAN. 
 
 Mayer (Ann. Ch. Phann. ci. 144), obtained from 100 pts. of air-dried Mazngan 
 beans, 11-8 to 12'5 per cent, water, 1-13 and 1-18 phosphoric anhydride, and 4-25 to 
 4-3 nitrogen. In dwarf haricot beans, he found 10-1 per cent, water, T06 phosphoric 
 anhydride, and 3'32 nitrogen ; in climbing haricot beans, 9-4 per cent, water, 0'95 
 phosphoric anhydride, and 3-17 nitrogen. 
 
 The sugar occurring in beans is usually regarded as grape-sugar. Vohl (Ann. Ch. 
 
 TABLE B. Composition (in 100 pts.) of 
 
 
 Potash, 
 K 2 O. 
 
 Soda, 
 
 Lime, 
 
 Magnesia, 
 
 I. SEED. 
 Faba vulgaris. 
 1. Common field bean from Holland . . . 
 2. Alsace .... 
 3. Giessen . . . 
 4. England . . . 
 5 Mazagan bean (seed sown) ..... 
 
 20-8 
 46-3 
 33-9 
 517 
 367 
 
 17'8 
 
 13-0 
 0-5 
 
 o-i 
 
 7-3 
 5-3 
 4-9 
 5-2 
 12*1 
 
 8-9 
 9-0 
 6-3 
 6-9 
 6'0 
 
 6. raised therefrom on clay soil . . . 
 7. sandy soil . . . 
 8 Heligoland bean (seed sown) . 
 
 43-4 
 457 
 42-9 
 
 1-3 
 1-6 
 
 5-8 
 13-3 
 
 77 
 
 57 
 6-5 
 
 77 
 
 9. raised therefrom on clay soil . . . 
 10. sandy soil . . . 
 
 PJiaseolus vulgaris. 
 
 43-5 
 407 
 
 38-9 
 
 2-4 
 11-3 
 
 4-8 
 
 8-2 
 
 5-9 
 
 5-6 
 
 77 
 
 9-0 
 
 
 51-0 
 
 
 6-0 
 
 11-9 
 
 13. Kurhessen .... 
 14 England 
 
 22-1 
 36-8 
 
 21-4 
 18'4 
 
 5-5 
 
 77 
 
 6-3 
 
 H. STBAW. 
 
 15-3 
 
 13-3 
 
 39-3 
 
 
 16 , 
 
 32-8 
 
 2-8 
 
 19-8 
 
 2'5 
 
 17 Mazagan bean on clay soil 
 
 187 
 
 13-9 
 
 18-9 
 
 3-1 
 
 18 sandy soil 
 
 25-6 
 
 
 22-4 
 
 47 
 
 
 19-6 
 
 
 18-3 
 
 4-9 
 
 20. sandy soil .... 
 
 21-1 
 
 0-2 
 
 25-6 
 
 6-9 
 
 1. Analysed by Bichon(Handw. d. Chem. 2 te Aufl.ii. [2] 259). 2.Boussingault 
 (iMd.} 3. ByBiichner (ibid,') 4-10 and 16-20. Way and Ogston (Journal of 
 the Royal Agricultural Society, ix. pt. 1). 11. Levi (Handw.) 12. Boussingault 
 (ibid,) 13. Thon (ibid.) 14. Richardson (Jahresber. f. Chem. 1847, 1848, p. 1075, 
 Tafel C). 15. Hertwig (Handw.) This contained carbonic acid, which has been 
 deducted. 
 
 The pods of Phaseolus multiftorus contain, according to T. J. Herapath (Chem. Soc. 
 Qu. J. 4), 94'1 percent, water ; air-dried, they yielded 0'631 per cent., and, after drying 
 at 100C., 10*7 per cent, of ash, containing: 
 
 Of matter soluble in water : 14*1 carbonic anhydride; 3 '4 sulphuric anhydride ; 
 1-5 phosphoric anhydride; 36*1 potash; 4-9 chloride of sodium. 
 
 Of matter insoluble in water: 22'2 carbonate of calcium; 3 -8 carbonate of mag- 
 nesium; 11'9 phosphate of calcium; and 2'1 silica. 
 
 BEAinvTONTITE. A mineral found in the gneiss at Jones Falls near Balti- 
 more, in North America, in square pyramids, having terminal dihedral angles of 147 
 28', and the lateral edges replaced by the square prism oo P. 
 
 Cleavage parallel to QO P. Yellowish-white to honey-yellow, translucent, with 
 nacreous lustre. Specific gravity 2 - 24. Hardness 4 -5 to 5*0. According to D e 1 e s s e 
 (Ann. Ch. Phys. [3] ix. 385), it contains 64-2 silica, 14'1 alumina, 4-8 lime, 17 mag- 
 nesia, 1'2 protoxide of iron, 0*6 soda (and loss), 13 -4 water. Alger and Dana are of 
 opinion that the mineral thus characterised is merely stilbite, the form of which has 
 been incorrectly determined, and the analysis made with impure material. 
 
BEAN BEBIRINE. 
 
 525 
 
 Phdrm. xcix. 125), found, in the unripe seeds, another kind of sugar, -which he at 
 first regarded as a peculiar substance, designated by him as phaseomannite, from ita 
 resemblance to mannite. According to later investigations, however, it appears to be 
 identical with inosite, the saccharine substance which Scherer obtained from muscular 
 flesh. 
 
 the Ash of Bean Seed and Bean Straw. 
 
 Sesqui- 
 oxide of 
 iron, 
 Fe 1 Q3. 
 
 Sulphuric 
 anhydride. 
 SO 3 . 
 
 Silica, 
 SiO*. 
 
 Carbonic 
 anhydride, 
 CO*. 
 
 Phos- 
 >horic an- 
 hydride, 
 
 P20 S . 
 
 Ch'orideof 
 potassium, 
 KCI. 
 
 Chloride 
 of sodium, 
 NaCl. 
 
 Ash per cent. 
 
 In sub- 
 stance un- 
 dried. 
 
 In sub- 
 stance 
 dried at 
 100" C. 
 
 1-0 
 
 1-3 
 
 2-4 
 
 
 38-0 
 
 
 2-4 
 
 
 
 
 
 1-6 
 
 0-5 
 
 i-o 
 
 357 
 
 1-5 
 
 
 
 
 07 
 
 
 
 0-5 
 
 
 
 40-5 
 
 
 
 
 
 trace 
 
 3-0 
 
 0-4 
 
 3-4 
 
 287 
 
 
 
 
 
 2-37 
 
 2-65 
 
 0-6 
 
 4-3 
 
 1-5 
 
 1-6 
 
 337 
 
 
 
 3-2 
 
 2-85 
 
 3-43 
 
 o-i 
 
 3-1 
 
 0-4 
 
 3-4 
 
 367 
 
 
 
 
 
 2-68 
 
 3-01 
 
 0-6 
 
 3-1 
 
 0-4 
 
 0-8 
 
 26-9 
 
 0-9 
 
 1-8 
 
 2-48 
 
 2-97 
 
 0-3 
 
 5-1 
 
 2-2 
 
 2-6 
 
 29-9 
 
 
 
 
 
 2-54 
 
 2-90 
 
 o-i 
 
 6-2 
 
 07 
 
 2-8 
 
 30-6 
 
 
 
 3-2 
 
 2-53 
 
 2-94 
 
 0-3 
 
 5-3 
 
 0-04 
 
 0-3 
 
 33-3 
 
 1-2 
 
 3-2 
 
 2-80 
 
 3-83 
 
 o-i 
 
 2-5 
 
 0-4 
 
 
 31-3 
 
 
 0-5 
 
 
 
 
 
 1-3 
 
 1-0 
 
 3-3 
 
 28-4 
 
 0-2 
 
 
 
 
 0-3 
 
 2-3 
 
 1-5 
 
 
 
 35-9 
 
 
 
 3-4 
 
 
 
 2-8 
 
 4-0 
 
 4-1 
 
 
 
 17-0 
 
 
 
 2-8 
 
 0-68 
 
 
 2-0 
 
 21 
 
 11-3 
 
 
 12-1 
 
 
 0-4 
 
 
 
 0-6 
 
 1-4 
 
 2-6 
 
 25-3 
 
 0-5 
 
 
 
 11-5 
 
 4-97 
 
 5-56 
 
 07 
 
 1-4 
 
 2-2 
 
 24-4 
 
 6-5 
 
 
 
 10-0 
 
 5-17 
 
 5-81 
 
 0-5 
 
 5-4 
 
 4-6 
 
 22-6 
 
 3-3 
 
 
 
 6-9 
 
 4-64 
 
 5-05 
 
 0-4 
 
 3-9 
 
 1-5 
 
 257 
 
 11-1 
 
 3-6 
 
 11-0 
 
 6-47 
 
 7'24 
 
 2-0 
 
 2-1 
 
 7-3 
 
 181 
 
 8-4 
 
 
 
 8-3 
 
 6-05 
 
 6-69 
 
 The name Beaumontite is also given by Jackson to a variety of siliceous malachite, 
 or an allied mineral containing silica, water, and oxide of copper. 
 
 BEBXRZC ACID. An acid contained, according to Maclagan, in the bark of 
 the Bcbeeru or Sipeeri (Nectandra Rodiei), a tree growing in British Guiana. To ob- 
 tain the acid, the bark is exhausted with water acidulated with acetic acid ; the 
 alkalis, bebirine and sepirine, with which the acid is in combination, are precipitated 
 by ammonia ; the filtered liquid is precipitated by acetate of lead ; the precipitate 
 decomposed by sulphuretted hydrogen ; the clear liquid evaporated over sulphuric 
 acid; and the residue digested in ether, which dissolves the acid, but leaves the 
 colouring matter. On evaporating the ethereal solution, bebiric acid remains as a 
 white crystalline substance, having a waxy lustre. By exposure to the air, it is gra- 
 dually reduced to a syrupy liquid. It melts a little above 200 C., and sublimes in 
 tufts of needles. With potash and soda, it forms deliquescent salts soluble in alcohol ; 
 sparingly soluble salts with the alkaline earths ; the lead-salt also is but sparingly 
 soluble in alcohol. 
 
 HEBEERITJE. C 19 H 21 N0 3 or C* 9 IP } N0 6 . An alkaloid dis- 
 covered in 1834 by Dr. Kodie of Bemerara, in the bark of the bebeeru tree (vid. sup.\ 
 Maclagan in 1843 (Ann. Ch. Pharm. xlviii. 106), showed that Eodie's bebirine 
 was a mixture of two distinct alkaloids, which he denominated bebirine and sepirine. 
 The former of these was more exactly investigated in 1845 by Maclagan and Tilley 
 (Phil. Mag. xxvii. 186), who assigned to it the formula C^H^NO 6 . But bebirine 
 
526 BEBIRINE -BEECH. 
 
 was first obtained perfectly pure by v. PI ant a (Ann. Ch. Pharm. Ixxvii. 333), who 
 assigned to it the formula above given. 
 
 Preparation. 1. The bark is exhausted with water containing sulphuric acid ; the 
 extract is concentrated, filtered, and precipitated by ammonia ; and the precipitate, 
 consisting of bebirine, sepirine, and tannin, is dried, dissolved in acidulated water, 
 and decolorised with animal charcoal. The solution again decomposed by ammonia, 
 yields a nearly colourless precipitate of bebirine and sepirine. As, however, the 
 treatment with animal charcoal always occasions a certain loss of alkali, it is better to 
 triturate the precipitate while yet moist with oxide of lead or milk of lime, dry the 
 mixture over the water-bath, extract the two alkaloids by means of alcohol, and 
 evaporate the alcoholic solution. To separate the two alkaloids, the product is ex- 
 hausted with ether, which dissolves only the bebirine (Maclagan and Pilley). 
 2. The bebirine prepared by the process just described, is not quite pure, and does 
 not dissolve completely in ether. It may be purified by treating it with acetic acid, 
 adding acetate of lead to the filtrate, precipitating the mixture with caustic potash, 
 washing the precipitate with a large quantity of cold water, and redissolving in ether. 
 The ethereal solution, when evaporated, leaves the bebirine in the form of a clear 
 yellow syrup, which is dissolved in a small quantity of strong alcohol, and the solution 
 is added drop by drop to a considerable quantity of water, with constant agitation : 
 bebirine then separates in the form of a floculent precipitate, (v. Planta.) 
 
 Bebirine when dry, is a white, amorphous, odourless powder, which does not change 
 by exposure to the air, and becomes electrical by friction. It melts at 198 C. to a 
 vitreous mass, which decomposes at a higher temperature. By boiling with strong 
 nitric acid, it is converted into a yellow pulverulent substance. Heated with chromic 
 acid, it yields a black resin. It does not yield chinoline when heated with caustic 
 potash. 
 
 Bebirine is nearly insoluble in water, but dissolves readily in alcohol and ether, 
 especially with the aid of heat. The solution has an alkaline reaction, and a very 
 persistent bitter taste. It dissolves readily in acetic and hydrochloric acid, forming 
 bitter uncrystallisable salts. It is precipitated from its solutions by dilute nitric 
 acid. 
 
 Hydrochlorate of bebirine is very soluble in water ; and the solution treated with 
 caustic alkalis or their carbonates yields bebirine in white flakes, easily soluble in ex- 
 cess of the reagents. The chloromercurate is obtained by adding mercuric chloride 
 to the solution of the hydrochlorate ; a small quantity of hydrochloric acid or chloride 
 of ammonium increases the precipitate ; but an excess redissolves it. The chloroaurate 
 is a brown-red precipitate. The chloroplatinate, C 19 H 21 N0 3 .HCl.PtCP, is an orange- 
 yellow amorphous precipitate, insoluble in hydrochloric acid. The sulphocyanate is 
 a white precipitate ; the pier ate yellow. 
 
 Sulphate of bebirine in the impure state has been used as a remedy in intermittent 
 fever. 
 
 The bark of the bebeeru tree, which has a bitter and astringent taste, contains 
 about 2 '5 per cent of bebirine and sepirine, together with bebiric acid and a peculiar 
 tannin ; the seed contains the same principles, together with about 50 per cent, of 
 starch, which impedes the extraction of the bases and acid. 
 
 BECKZTE. This name has been given to a mineral from Paynton in Devonshire, 
 which, according to Kenngott, is merely a coral hardened into a chalcedonic or horn- 
 stone variety of quartz, intergrown with compact grey limestone. 
 
 BEECH. Fagus sylvatica. Beech-wood recently felled, has a specific gravity of 
 0*982, and contains 40 per cent, water ; after drying in the air, it has a specific gravity 
 of 0-590, and contains 18 to 20 per cent, water. After drying at 100 C. it contains, 
 according to Baer (Arch. Pharm. [2] Ivi. 159), 46'1 to 48-3 per cent, carbon, 5'8 to 
 6-0 hydrogen, 46'6 to 45'1 oxygen, and 1*2 to 0*6 ash. According to Chevandier 
 (Compt. rend. xxiv. 269), it contains 49'8 per cent. C, 6-0 H, 43'1 0, M N, and 
 yields 1-06 per cent. ash. According to Sprengel (J. techn. Chem. xiii. 384), the 
 air-dried wood yields 0-365 per cent, ash, containing 0'14 crude carbonate of potash ; 
 and the leaves which fall in autumn yield 6 '695 per cent. ash. 
 
 The following table exhibits the composition percent, of the ash of beech-wood, and 
 of the leaves, a, g, h are by Sprengel (loc. tit.}; b, c (Witting, Pharm. Centr. 
 1851, 104); b, of wood grown on sandstone (buntcr Sandstciri), near Marburg; c of 
 wood grown on the Muschelkalk, near Morschen in Kurhessen ; d, e, f (Hey er and 
 Vonhausen, Ann. Ch. Pharm. Ixxxii. 180). The wood was grown on a basaltic 
 hill near Giessen. A hectare of surface produced yearly 2-672 cubic metres of stem- 
 wood (Scheitholz}; 0-965 c. m, large branch-wood (Prugelholz) ; 0769 c. m. small 
 branch-wood (Stockholz); and 1-878 c. m. of twigs (Reisholz}; and these quantities 
 
BEECH BEER. 
 
 527 
 
 of wood extracted from the soil, in all, 51 '3 kilogrammes of ash, viz. the stem-wood 
 17'0 kil., the large branch-wood 9-9 kil., the small branch-wood 4-9 and the twig- 
 wood 19*5 kil. Hence a cubic metre of the stem- wood yields 6*342 kilogrammes 
 of ash; of large branch- wood 10*233 kil.; and of twig-wood 14-144 kil, The table 
 shows also that, reckoning from the bottom upwards, the proportion of alkali dimi- 
 nishes, that of the phosphoric and sulphuric acid increases ; while of silica, the twigs 
 have more than the stem, and the thick branches least of all. 
 
 Potash . 
 Soda . 
 Lime . 
 Magnesia . 
 
 ^ 
 a 
 
 Wood. 
 
 * 
 b 
 
 ~s 
 
 c 
 
 Wood with Bark. 
 
 Leaves. 
 
 Stem. 
 
 Large 
 Branches. 
 
 Twigs. 
 
 d 
 
 e 
 
 / 
 
 g 
 
 h 
 
 249 
 1-1 
 274 
 6-6 
 2-2 
 
 7-4 
 
 7-1 
 5-2 
 
 15-1 
 2*6 
 
 10-9 
 1-2 
 13-5 
 12-0 
 0-05 
 
 T-4 
 1-0 
 6'3 
 
 26-2 
 5-6 
 
 G-7 
 2-1 
 107 
 
 6-9 
 0'3 
 43-6 
 5-4 
 
 0-6 
 trace 
 (Hi 
 
 i-i 
 
 283 
 7-5 
 
 0-6 
 3-7 
 
 13'1 
 3-1 
 
 39-8 
 
 10-1 
 
 0-5 
 0-9 
 04 
 6-2 
 19-6 
 6-0 
 
 o-i 
 
 12-5 
 1-7 
 37-8 
 13-4 
 
 0-3 
 1-0 
 05 
 5-5 
 17-4 
 96 
 
 0-8 
 
 11-8 
 i-8 
 40-2 
 9-0 
 
 0-6 
 0-fi 
 1-0 
 8- '2 
 16-3 
 10-3 
 
 0-1 
 
 07 
 51-7 
 6-1 
 
 HI 
 
 0-8 
 4-1 
 1 9 
 27-0 
 
 (Fe 
 
 5-1 
 1-0 
 37-7 
 7-9 
 
 0-4 
 2-4 
 1'3 
 
 28'5 
 10-5 
 4 8 
 
 0-3 
 
 Ferric oxide 
 Manganic oxide 
 Sulphuric anhydride 
 Silica 
 
 Carbonic anhydride 
 Phosphoric . 
 Ferric phosphate 
 Chloride of sodium 
 Charcoal ..... 
 
 
 
 The barJc of the beech contains, together with the usual constituents of vegetable 
 substances, about 2 per cent, of tannin, also a peculiar red substance, and another 
 which smells like vanilla. The latter is soluble in alcohol, insoluble in water and in 
 ether ; and by shaking up the alcoholic solution with hydrate of lead, and repeated 
 precipitation by water, it may be obtained as an amorphous white powder, with an 
 odour of vanilla and a bitter taste. It dissolves in acetic acid and in alkalis ; nitric 
 acid converts it into oxalic acid. (Lepage, J. Pharm. [3] xii. 181.) 
 
 Dry beech-bark yields about 0'6 per cent, crude potash. According to Hertwig 
 (Ann. Ch. Pharm. xlvi. 97), it yields 6'6 per cent, ash, containing in 100 pts. 3'0 
 soluble salts, consisting of alkaline carbonates, sulphate of potassium, and a trace of 
 chloride of sodium, and 97 '0 pts. of insoluble salts, viz. 64'7 carbonate of calcium, 
 16-9 magnesia, 2*7 phosphate of calcium, 1*9 phosphates of magnesium, aluminium, 
 and iron, and 9-0 silica. 
 
 The ash of beech-nuts yields in 100 pts. 18-1 K 2 0, 7'5 Na 2 0, 19'5 Ca 2 0, 9'2 Mg 2 0, 
 2-5 Mn 3 2 , 16-5 P 2 5 , 0-7 NaCl. 1'5 SiO 2 , 9-1 CO 2 , and 9'4 charcoal. (Handw. d. Chern. 
 2* Aufl. ii. [2] 549.) 
 
 BEECH-1UX7T OIL. Huile de faine. C I5 H 28 2 . Beech-nuts yield, by pressure, 
 about 17 percent, of a clear, light-yellow, viscid oil, inodorous, having a mild taste and 
 a density of 0-9225 at 15 C. It solidifies at 17 C., and is coloured rose-red by 
 nitric acid. It is a non-drying oil, and yields a white soap. It is used in cooking and 
 for illumination. Mixed with eight or ten times its bulk of water, and treated at 60 
 or 80 C. with chlorine gas, it is converted into a chlorinated oil containing C I5 H 26 C1 2 2 . 
 Bromine acts on it with violence, but if the oil be cooled at the same time, the com- 
 pound C 15 H 26 Br'-'0 2 is produced. (Lefort, Compt. rend. xxxv. 734.) 
 
 is the wine of grain, and is prepared from malt, or grain, generally barley, 
 which has been allowed to germinate. The grain is steeped for two or three days in 
 water, until it swells, becomes somewhat tender, and tinges the water of a bright 
 reddish-brown colour. The water being then drained away, the barley is spread about 
 two feet thick upon a floor, where it heats spontaneously, and begins to grow by first 
 shooting out the radicle. In this state, the germination is stopped by spreading it 
 thinner, and turning it over for two days ; after which it is again made into a heap, 
 and suffered to become sensibly hot, which usually happens in little more than a day. 
 Lastly, it is conveyed to the kiln, where, by a gradual and low heat, it is rendered dry 
 and crisp. This is malt, and its qualities differ according as it is more or less soaked, 
 drained, germinated, dried, and baked. 
 
 Malt is distinguished by its colour, as pale, amber, brown, or black malt, accord- 
 
528 BEER. 
 
 ing to the different degrees of heat to which it has been subjected. Pale malt is 
 produced when the drying temperature does not exceed 90 to 100 F., amber- 
 coloured malt when the heat has been raised to 120 to 125, and brown malt at 150 
 to 170. Black malt, commonly called patent malt, is prepared by roasting in 
 cylinders like coffee, at a heat of 360 to 400 F. ; it is used as colouring matter in the 
 brewery of porter. 
 
 Indian corn, and probably all large grain, requires to be suffered to grow into the 
 blade, as well as root, before it is fit to be made into malt. For this purpose, it is 
 buried about two or three inches deep in the ground, and covered with loose earth ; 
 and in ten or twelve days it springs up. In this state, it is taken up and washed, or 
 fanned, to clear it from dirt ; and then dried in the kiln for use. 
 
 During the process of germination, the albuminous matter of the barley or other 
 grain is brought into the peculiar state called diastase, in which it acts as a ferment 
 on the starch contained in the grain, converting it into dextrin and sugar, and thereby 
 rendering it soluble. A portion of the starch is, however, always left unchanged by 
 the germinating process, and its conversion into dextrin and sugar is completed by 
 the kiln-drying. The benefit of this latter process is, therefore, not confined to the 
 mere expulsion of moisture from the grain ; indeed kiln-dried malt always yields a 
 larger quantity of saccharine extract than malt which has been left to dry in the air at 
 ordinary temperatures. 
 
 The diastase of malt is capable of converting into sugar a much larger quantity of 
 starch than that which the grain itself contains : hence in the preparation of the ex- 
 tract, the malt may be mixed with a certain quantity of unmalted barley or other 
 grain. In Belgium, large quantities of beer are prepared from malt mixed with 
 potato starch. 
 
 To make beer, the malt, after being ground or cut to pieces in a mill, is placed in a 
 tun or tub with a false bottom ; water at about 180 F. is then poured upon it ; and 
 the whole is well stirred about by suitable machinery. This operation is called mash- 
 ing. After the infusion has been left for a few hours to clarify or set, the clear liquor 
 or sweet wort is transferred to a copper boiler and boiled with hops, which give it a 
 bitter aromatic taste, and perhaps also render it less liable to spoil by keeping. 
 When the wort has been sufficiently boiled, it is drawn from the copper into large 
 shallow vessels, so as to cool it as rapidly as possible to the temperature of the air, 
 and thereby avoid an irregular acid fermentation, to which it would otherwise be liable. 
 It is then transferred to the fermenting vats, which in large breweries are of great 
 capacity, and mixed with yeast, the product of a preceding operation. The liquid is 
 thereby brought into a state of commotion ; the sugar is more or less converted into 
 alcohol and carbonic acid, which escapes as gas ; and the nitrogenous matter of the 
 extract is converted into yeast, part of which is expended in keeping up the fermenta- 
 tion, while the rest rises to the surface. The fermentation is never suffered to run 
 its full course, but is always stopped at a certain point, by separating the yeast and 
 drawing off the beer into casks. A slow and almost insensible fermentation then 
 takes place, whereby more of the sugar is converted into alcohol, and the beer is rendered 
 stronger and less saccharine. 
 
 During this last process, the beer gradually becomes clear or fine, the solid par- 
 ticles of yeast which float about in it during the fermentation, and render it muddy, 
 being gradually brought to the surface and discharged through the bung-holes of the 
 casks, whence the yeast is conveyed into proper receptacles. A very effective ar- 
 rangement for this purpose is adopted at the extensive breweries of Messrs. Bass and 
 Allsopp at Burton-on-Trent, for a description and figure of which see Muspratfs 
 Chemistry, vol. i. p. 276. Frequently, however, it is found necessary to assist the 
 clarification by means of substances called finings, which lay hold of the suspended 
 matter, and precipitate it to the bottom. Isinglass dissolved in sour beer is often 
 used for this purpose, also gelatin, white of egg, serum of blood, Carragheen moss, 
 and the dried stomach of the cod, called sounds. It is best, however, when the 
 clarification takes place spontaneously, without the usa of finings ; for all these sub- 
 stances tend to make the beer flat, and prevent it from carrying a good head. The 
 composition of the water used in brewing has a great influence on the result. Lime 
 in particular appears to favour the clarification, by combining with the acids of 
 the malt-extract, and forming insoluble salts, which carry down the suspended 
 matter. The spring- water of Burton-on-Trent (not that of the river Trent) contains 
 19 per cent, of sulphate of lime, only a small portion of which is precipitated on 
 boiling. 
 
 The strength and taste of beer are susceptible of endless variety, according to the 
 quality and quantity of the malt and hops used, and the mode of conducting each 
 stage of the process, but especially the fermentation. If the first fermentation be 
 
BEER. 529 
 
 stopped at an early stage, the beer will contain a considerable quantity of sugar and 
 comparatively little alcohol : it will be mild, and if bottled, will acquire the property 
 of effervescing strongly when the bottle is opened, because the carbonic acid produced 
 by the subsequent slow fermentation, remains dissolved in the liquid, and escapes with 
 violence as soon as the pressure is removed. If, on the other hand, the fermentation 
 be allowed to go on in the vat or in casks, till nearly all the sugar is converted into 
 alcohol and the carbonic acid escapes, the beer then becomes more alcoholic ; but if 
 the process be allowed to go on too long, it loses its briskness and becomes flat and 
 unpalatable. Strong beers are those which contain a considerable amount of alcohol ; 
 substantial beers are those which are rich in malt-extract; the latter are also said to 
 possess body. 
 
 The malt-liquors consumed in this country are of two kinds, ALE and POUTER. Ale 
 is prepared from the paler kinds of malt, and in its preparation, the first fermentation 
 is checked at such a stage as to leave a considerable quantity of saccharine matter in 
 the liquor, which, by its subsequent conversion into alcohol and carbonic acid, may 
 keep up the briskness. The ale is mild or bitter, according to the quantity of hops 
 added to the wort. Pale ale is prepared from the palest malt dried in the sun or by 
 steam heat, and from the best and palest hops. An essential point in its preparation 
 is to keep the fermenting temperature as low as possible, never allowing it to rise 
 above 72 F. By this means, the formation of acetic acid is prevented, as also the 
 solution of the yeast by alcohol, which always communicates an unpleasant flavour to 
 the liquor, and the delicate flavour and aroma of the hop are preserved. Scotch ale 
 is a sweet strong ale; it was formerly flavoured with honey, but that practice appears 
 to be now abandoned. - 
 
 Porter is a dark-coloured beer, prepared from a mixture of pale, amber, brown, and 
 black malt. The following table (taken from Muspratt's Chemistry) exhibits the 
 composition of the various mixtures employed : 
 
 Table of Porter Grists. 
 
 No. Black. Brown. Amber. Pale. Total. 
 
 1 . .9 . .0 . .0 . .91 . ,.100 
 
 2 . .6 . .34 . . 0. . .60 . .100 
 
 3 . . 2 . 30 . .10 . .58 . .100 
 
 4 . .3 . .25 . .15 . .57 . .100 
 
 5 . .4 . .24 . .24 . .48 . .100 
 
 6 . .5 . .0 . .95 . .0 . .100 
 
 Of these the preference is given to the last two ; in the others, the excess of black and 
 brown malt introduces too much carbonaceous and useless matter, whence the porter 
 acquires a disagreeable taste, as if liquorice were added to it. The fermentation of 
 porter in the vats is carried on till the original gravity of the liquid is reduced to 
 about one-third. Stout is merely a stronger kind of porter. Small beer, as its namo 
 implies, is a weaker liquor, and is made either by adding a large quantity of water to 
 the malt, or by mashing with a fresh quantity of water, the residuum left after ale or 
 porter has been drawn off. 
 
 The temperature at which the fermentation of beer is conducted, has a marked 
 effect on its quality, and especially on its power of keeping without turning sour. 
 When the fermenting temperature ranges from 65 to 90 F., as is the case with the 
 beers of England, France, Belgium, and most parts of Germany, the beer gradually 
 becomes sour by contact with the air, the alcohol being slowly converted into acetic 
 acid. But Bavarian beer, which is fermented at a much lower temperature, 8 or 10 
 C. (46*5 to 50 F.), does not undergo this change. The difference arises from the 
 manner in which the fermentation takes place, and is explained by Liebig as follows : 
 Wort is proportionally richer in soluble gluten than in sugar, and when set to ferment 
 in the ordinary way, it evolves a large quantity of yeast in the state of a thick froth, 
 with bubbles of carbonic acid gas adhering to it, whereby it is floated to the surface 
 of the liquid. Now the conversion of gluten into yeast is partly, at least, a process of 
 oxidation; and when the liquor is covered with a thick scum, as just described, the 
 gluten stil dissolved in the liquid, not having free access to the air, appears to take 
 oxygen from the sugar and other matters contained in the liquid, the formation of the 
 yeast thus going on at the expense of the sugar, which is consequently destroyed before 
 the whole of the gluten is converted into yeast. From this cause, a quantity of free 
 gluten is left in the liquid, and on subsequent exposure to the air, this gluten acts as 
 a ferment, inducing the conversion of the alcohol into acetic acid. In the Bavarian 
 process, on the contrary, the carbonic acid, instead of escaping in large bubbles, which.' 
 carry the yeast to the surface, rises in minute bubbles in the same manner as from 
 
 VOL. I. M M 
 
530 BEER. 
 
 an effervescing mineral water ; little or no scum forms on the surface, but the yeast, as 
 it is produced, sinks to the bottom, and leaves the surface of the wort freely exposed 
 to the air. The gluten is thus converted into yeast by atmospheric oxidation, and is at 
 last wholly removed from the liquid without decomposition of the sugar. Beer thus 
 fermented, is not liable to acidification by exposure to the air. 
 
 The kind of fermentation last described, is called bottom fermentation (Unter- 
 gahrung), and the yeast produced by it bottom yeast ( Unterhefe} ; while the ordi- 
 nary fermentation process is called top fermentation (Obergahrung), and the 
 yeast which it produces top yeast (Oberhefe\ These two kinds of yeast differ 
 essentially in their properties and mode of action. The top-yeast is gluten oxidised in 
 a state of putrefaction, and the bottom yeast is the gluten oxidised by cremacausis or 
 slow combustion. Each of them has a tendency to induce the particular kind of fer- 
 mentation by which it was itself produced. (See FERMENTATION.) 
 
 For further details respecting the preparation and properties of beer, see the articles 
 BEER and BREWING in the new edition of Ure's Dictionary of Arts, Manufactures, and 
 Mines ; also the article BEER in Muspratfs Chemistry, and in the Handworterbuch 
 der Chemie, 2 te Aufl. ii. [1] 103-6 
 
 ANALYSIS OF BEER. The normal constituents of beer are alcohol, carbonic acid, 
 and extractive matters of malt and hops ; acetic acid is also present, but its amount 
 in good beer is very small. 
 
 The amount of carbonic acid in beer is but small, not exceeding 0-1 to 0'5 per 
 cent, even in bottled beer, and of this small quantity the greater portion escapes 
 as soon as the beer is opened. The strength of the frothing will give a very good 
 idea of its relative amount. An exact estimation of the carbonic acid is indeed 
 seldom necessary ; but if desired, it may be made by boiling a known quantity of 
 the beer in the flask-apparatus, represented in fig. 5, p. 119, (art. ALKALIMETRY.) 
 The carbonic acid (anhydrous) then escapes as gas, while the vapours of water 
 and alcohol given off at the same time are retained by the chloride of calcium in 
 the drying tube. 
 
 The amount of acetic acid is estimated by the usual processes of ACIDIMETRY 
 
 (*) 
 
 The quantity of extractive matter in beer maybe determined by evaporating 
 20 grammes of beer in a platinum or porcelain dish, and drying the residue in an air- 
 bath (p. 520) at 100 115 C. till it ceases to lose weight. Before weighing, it 
 must be cooled under a bell-jar over chloride of calcium, as it is very hygroscopic. 
 
 It is seldom necessary to examine the extractive matter any further. It .consists 
 mainly of sugar, dextrin, albuminous matter, and lupulin, the bitter principle of the 
 hop. The amount of dextrin and sugar may be determined by moistening the dried 
 residue with water to a thin syrup, and gradually adding strong alcohol as long as dextrin 
 is thereby separated. The clear sugar-solution may then be decanted, and the dextrin 
 freed from the remaining sugar by repeated solution in water and precipitation by 
 alcohol. The solutions of dextrin and sugar may then be evaporated to dry ness, and 
 the residues weighed. The albuminous matter may be estimated from a separate por- 
 tion of the beer by boiling it so as to coagulate the albumin, collecting the precipitate 
 on a tared filter, then washing, drying, and weighing it. Lastly the sum of the 
 weights of the dextrin, sugar, and albuminous matter, deducted from the total weight 
 of the extract gives the quantity of lupulin. 
 
 The inorganic constituents of beer are estimated by evaporating to dry ness a 
 known quantity of the beer, charring the residue, and then igniting it, as in the prepara- 
 tion of plant-ashes (p. 419). They consist chiefly of the phosphates of calcium and 
 magnesium. Alkaline phosphates may likewise be found, but the greater part of 
 them is dissolved out during the maceration of the barley for malting. Common salt, 
 which is sometimes added to beer, will of course be found in the ash. Any consider- 
 able amount of alkaline carbonate may be attributed to alkali added to neutralise free 
 acid in the beer. 
 
 The amount of alcohol in beer is ascertained by distilling 500 to 1000 grammes 
 (15 to 30 ounces) in a somewhat capacious retort, having its neck inclined upwards and 
 connected with a Liebig's condenser, receiving the distillate in a tared flask, weighing 
 it, and determining its specific gravity at 15 C. (60 F.), that of water at the same 
 temperature being assumed = I'OOO ; or the proportion of alcohol may be found by 
 testing the distillate with a delicate alcoholometer. The weight per cent, of alcohol is 
 then found by means of table A, which is an amplification of part of that given 
 under ALCOHOLOMETRY (p. 81), and thence the total amount of alcohol in the given 
 quantity of beer may be found. 
 
 Suppose, for instance, 1000 grms. of beer gave 615'38 grins, of distillate of specific 
 
BEER. 
 
 531 
 
 gravity 0*98949 at 60 F. ; then, according to the table, the distillate would contain 
 6-11 per cent, alcohol, and therefore the 615-38 grms. of distillate would contain 37*6 
 grms. alcohol. Now thess 3 7 '6 grms. of alcohol were obtained from 1000 grms. of beer ; 
 consequently the amount of alcohol in the beer is 376 per cent. The trouble of 
 calculation may be saved by diluting the distillate till its weight becomes equal to 
 that of the beer employed ; the specific gravity will then at once give the percentage 
 by weight of alcohol in the beer. If, for example, the distillate after dilution exhibited 
 a specific gravity = 0-9932, the percentage of alcohol would be 376. If a Tralles' 
 alcoholometer were used, it would show in the distillate, before dilution, a percentage 
 by volume of 7'6, corresponding to 6'11 by weight. In using the alcoholometer, it is 
 best not to dilute the distillate, unless the instrument is especially graduated for very 
 weak liquids. If the observed specific gravity or alcoholometer-degree does not occur 
 in the table, the weight per cent, of alcohol will be found by interpolation. 
 
 TABLE A. Specific Gravity and Strength of Spirits. 
 
 Volume 
 per cent. 
 
 Weight 
 per cent. 
 
 Specific Gravity. 
 
 Volume 
 per cent. 
 
 Weight 
 per cent. 
 
 Specific Gravity. 
 
 1- 
 
 0-80 
 
 0-99850 
 
 4-5 
 
 3-60 
 
 0-99350 
 
 1-1 
 
 0-88 
 
 0-99835 
 
 4-6 
 
 3-68 
 
 0-99336 
 
 1-2 
 
 0-96 
 
 0-99820 
 
 4-7 
 
 376 
 
 0-99322 
 
 1-3 
 
 1-04 
 
 0-99805 
 
 4-8 
 
 3-84 
 
 0-99308 
 
 1-4 
 
 1-12 
 
 0-99790 
 
 4-9 
 
 3-92 
 
 0-99294 
 
 1-5 
 
 1-20 
 
 0-99775 
 
 5-0 
 
 4-00 
 
 0-99280 
 
 1-6 
 
 28 
 
 0-99760 
 
 5-1 
 
 4-08 
 
 0-99267 
 
 17 
 
 36 
 
 0-99745 
 
 5-2 
 
 4-16 
 
 0-99254 
 
 1-8 
 
 44 
 
 0-99730 
 
 5-3 
 
 4-24 
 
 0-99241 
 
 1-9 
 
 52 
 
 0-99715 
 
 5-4 
 
 4-32 
 
 0-99228 
 
 2-0 
 
 60 
 
 0-99700 
 
 5-5 
 
 4-40 
 
 0-99215 
 
 2-1 
 
 68 
 
 0-99686 
 
 5-6 
 
 4-48 
 
 0-99202 
 
 2-2 
 
 76 
 
 0-99672 
 
 57 
 
 4-56 
 
 0-99189 
 
 2-3 
 
 84 
 
 0-99658 
 
 5-8 
 
 4-64 
 
 0-99176 
 
 2-4 
 
 92 
 
 0-99644 
 
 5-9 
 
 472 
 
 0-99163 
 
 2-5 
 
 2-00 
 
 0-99630 
 
 6-0 
 
 4-81 
 
 0-99150- 
 
 2-6 
 
 2-08 
 
 0-99616 
 
 6-1 
 
 4-89 
 
 0-99137 
 
 27 
 
 2-16 
 
 0-99602 
 
 6-2 
 
 4-97 
 
 0-99124 
 
 2-8 
 
 2-24 
 
 0-99588 
 
 6-3 
 
 5-05 
 
 0-99111 
 
 2-9 
 
 2'32 
 
 0-99574 
 
 6-4 
 
 5-13 
 
 0-99098 
 
 3-0 
 
 2-40 
 
 0-99560 
 
 6-5 
 
 5-21 
 
 0-99085 
 
 3-1 
 
 2-48 
 
 0-99546 
 
 6-6 
 
 5-30 
 
 0-99072 
 
 3-2 
 
 2-56 
 
 0-99532 
 
 6-7 
 
 5-38 
 
 0-99059 
 
 3-3 
 
 2-64 
 
 0-99518 
 
 6-8 
 
 5-46 
 
 0-99046 
 
 3-4 
 
 272 
 
 0-99504 
 
 6-9 
 
 5-54 
 
 0-99033 
 
 3-5 
 
 2-80 
 
 0-99490 
 
 7-0 
 
 5-62 
 
 0-99020 
 
 3-6 
 
 2'88 
 
 0-99476 
 
 7-1 
 
 570 
 
 0-99008 
 
 37 
 
 2-96 
 
 0-99462 
 
 7-2 
 
 578 
 
 0-98996 
 
 3-8 
 
 3-04 
 
 0-99448 
 
 7-3 
 
 5-86 
 
 0-98984 
 
 3-9 
 
 3-12 
 
 0-99434 
 
 7-4 
 
 5-94 
 
 0-98972 
 
 4-0 
 
 3-20 
 
 0-99420 
 
 7-5 
 
 6-02 
 
 0-98960 
 
 4-1 
 
 3-28 
 
 0-99406 
 
 7-6 
 
 6-11 
 
 0-98949 
 
 4-2 
 
 3-36 
 
 0-99392 
 
 77 
 
 6-19 
 
 0-98936 
 
 4-3 
 
 3-44 
 
 0-99378 
 
 7-8 
 
 6-27 
 
 0-98924 
 
 4-4 
 
 3-52 
 
 0-99364 
 
 7-9 
 
 6-35 
 
 0-98912 
 
 
 
 
 8-0 
 
 6-43 
 
 0-98900 
 
 The residue in the retort may be used for determining the amount of extractive 
 matter in the beer. For this purpose it is diluted with water, after cooling, till its 
 weight becomes equal to that of the beer before distillation, and the amount of extrac- 
 tive matter is then found from its specific gravity, by means of tables provided for the 
 purpose. 
 
 The following is taken from a more detailed table in the Handwortcrluch, 2 te Aufl. ii. 
 [1] 1081. 
 
 M M 2 
 
532 
 
 BEER. 
 
 TABLE B. Specific Gravity and Strength of Malt-Extract. 
 
 Specific 
 Gravity. 
 
 Malt-extract 
 in 100 pts. 
 of liquid. 
 
 Specific 
 Gravify. 
 
 Malt-extract 
 in 100 pts. 
 of liquid. 
 
 Specific 
 Gravity. 
 
 Vlalt extract 
 in 100 pts. 
 of liquid. 
 
 Specific 
 Gravity. 
 
 Malt-extract 
 in 100 pts. 
 of liquid. 
 
 I'OOO 
 
 o-ooo 
 
 1-018 
 
 4-500 
 
 1-036 
 
 8-925 
 
 1-054 
 
 13-238 
 
 1-001 
 
 u '250 
 
 1-019 
 
 4-750 
 
 1-037 
 
 9-170 
 
 1-055 
 
 13-476 
 
 1-002 
 
 0-500 
 
 1-020 
 
 5-000 
 
 1-038 
 
 9-413 
 
 1-056 
 
 13714 
 
 1-003 
 
 0750 
 
 1-021 
 
 5-250 
 
 1-039 
 
 9-657 
 
 1-057 
 
 13-952 
 
 1-004 
 
 1-000 
 
 1-022 
 
 5-500 
 
 1-040 
 
 9-901 
 
 1-058 
 
 14-190 
 
 1-005 
 
 1-250 
 
 1-023 
 
 5-750 
 
 1-041 
 
 10-142 
 
 1-059 
 
 14-428 
 
 1-006 
 
 1-500 
 
 1-024 
 
 6-000 
 
 1-042 
 
 10-381 
 
 1-060 
 
 14-666 
 
 1-007 
 
 1-750 
 
 1-025 
 
 6-244 
 
 1-043 
 
 10-619 
 
 1-061 
 
 14-904 
 
 1-008 
 
 2-000 
 
 1-026 
 
 6-488 
 
 1-044 
 
 10-857 
 
 1-062 
 
 15-139 
 
 1-009 
 
 2*250 
 
 1-027 
 
 6-731 
 
 1-045 
 
 11-095 
 
 1-063 
 
 15-371 
 
 1-010 
 
 2-500 
 
 1-028 
 
 6-975 
 
 1-046 
 
 11-333 
 
 1-064 
 
 15-604 
 
 1-011 
 
 2-750 
 
 1-029 
 
 7-219 
 
 1-047 
 
 11-595 
 
 1-065 
 
 15-837 
 
 1-012 
 
 3-000 
 
 1030 
 
 7-463 
 
 1-048 
 
 11-809 
 
 1-066 
 
 16-070 
 
 1-013 
 
 3-250 
 
 1-031 
 
 7-706 
 
 1-049 
 
 12-047 
 
 1-067 
 
 16-302 
 
 1-014 
 
 3-500 
 
 1-032 
 
 7-950 
 
 1-050 
 
 12-285 
 
 1-068 
 
 16-534 
 
 1-015 
 
 3750 
 
 1-033 
 
 8-195 
 
 1-051 
 
 12-523 
 
 1-069 
 
 16-767 
 
 1-016 
 
 4-000 
 
 1-034 
 
 8-438 
 
 1-052 
 
 12761 
 
 1-070 
 
 17-000 
 
 1-017 
 
 4-250 
 
 1-035 
 
 8-681 
 
 1-053 
 
 13-000 
 
 
 
 A more extended table of the specific gravity of pure syrup, which does not differ 
 greatly from that of malt-extract, is given in lire's Dictionary of Arts, Manufactures, 
 and Mines, new edition, vol. ii. p. 610. 
 
 The amount of alcohol in beer may in most cases be calculated with sufficient 
 accuracy for practical purposes, from the difference between the specific gravity of the 
 boiled and unboiled beer, according to the following principle : The specific gravity of 
 the unboiled beer is less than that of the boiled beer, in the same proportion as the specific 
 gravity of spirit of wine of equal alcoholic strength is less than that of water. To 
 determine the amount of alcohol in beer accordingly, the beer is first freed from car- 
 bonic acid by brisk agitation in a capacious flask, assisted perhaps by very gentle 
 warming, and its specific gravity is accurately determined. It is then boiled to drive 
 off the alcohol, and the residue is diluted with water, till its weight becomes exactly 
 equal to the original weight of the beer ; it is then filtered, if necessary, through a 
 covered filter, and its specific gravity likewise determined. The amount of alcohol is 
 then calculated, as in the following example. Suppose the specific gravity of the unboiled 
 beer, freed from carbonic acid, to be 1-0250 ; and after boiling and dilution with 
 water, to be increased to 1*0320. Then, according to the principle just stated, the 
 specific gravity of pure spirit of the same alcoholic strength as the beer, will be to 
 
 1-0250 
 
 that of water as 1-0320 : 1-0250 ; that is to say, it will be 
 
 1-0320 
 
 0-9932, which, ac- 
 
 cording to the table, page 531, corresponds to 3 -8 per cent. 
 
 The empirical rule for finding the specific gravity of spirit of equal strength with 
 the beer is : Divide the specific gravity of the unboiled beer by that of the boiled beer, 
 after its original weight has been restored by dilution. 
 
 It is clear that the results obtained by this method (called in Germany the Specific 
 Seer-test], will be more exact, in proportion as the composition of the beer differs less 
 from that of pure spirit of equal strength, in other words, the smaller the amount of 
 of the extractive matter contained in the beer. For beers like those of Bavaria, it 
 answers very well ; but for those which contain a larger amount of extract it cannot 
 be relied on. 
 
 For Balling's Saccharometric method (saccharimetrische Bierprobe), and Fuchs's 
 Hallymetric method (hallymetrische Bierprobe\ which latter consists in determining 
 the quantities of alcohol and extractive matter in beer by the quantity of common 
 salt which it is capable of dissolving, see Handwbrterbuch der Chemie, 2 te Aufl. ii. 
 [1] 1078; and Handbuch der technisch-chemischen Untersuchungen von P. A. Bolley, 
 2 te Aufl. Leipzig, 1861, s. 350. 
 
 The following tables C and D, exhibit the composition of various kinds of beer. 
 See also Jahresbericht fur Chemie, 1849, p. 708; 1850, p. 683 ; 1853, p. 758; 1855, 
 p. 852. 
 
BEER. 
 
 533 
 
 TABLE C. Average Amount of Malt-extract and Alcohol in various Kinds of Beer. 
 
 Name of Beer. 
 
 Percen 
 Malt-extract. 
 
 tageof 
 Alcohol. 
 
 London Ale, for exportation .... 
 London Ale, ordinary 
 London Porter, for exportation 
 London Porter, ordinary .... 
 
 75 
 54 
 76 
 54 
 5-53-5 
 53 
 43-5 
 85 
 6-54 
 6-25-7 
 
 68 
 45 
 56 
 34 
 4-56 
 2-54 
 44-5 
 3-54 
 3-^=4-5 
 1-82 
 
 Brussels Faro 
 Biere forte de Strasbourg .... 
 Biere blanche de Paris 
 
 White Beer of Berlin 
 
 TABLE D. Special Eesults of the examination of certain Seers. 
 
 Name of Beer. 
 
 Malt- 
 extract. 
 
 Percei 
 Alcohol. 
 
 itage of 
 
 Carbonic 
 acid.* 
 
 Water. 
 
 Analysed 
 by 
 
 London" Porter (Barclay and Perkins) . 
 London Porter 
 
 6-0 
 6-8 
 
 5-4 
 69 
 
 0-16 
 
 88-44 
 86-3 
 
 Kaiser. 
 Balling. 
 
 
 5*9 
 
 47 
 
 0-37 
 
 89-0 
 
 Ziurek. 
 
 
 14 5 
 
 5-9 
 
 
 79-6 
 
 Hoffmann. 
 
 
 10-9 
 6-3 
 
 8-5 
 7*6 
 
 0-15 
 0-17 
 
 80-45 
 85-93 
 
 Kaiser. 
 Ziurek. 
 
 Ale (Berlin) 
 
 
 3-4 
 
 5-5 
 
 0-2 
 
 90-9 
 
 Kaiser. 
 
 Brussels Faro 
 
 2-9 
 
 4-9 
 
 0-2 
 
 92-0 
 
 Kaiser. 
 
 
 9*4 
 
 4*6 
 
 0*18 
 
 85-85 
 
 Kaiser. 
 
 
 9-2 
 
 4-2 
 
 0'17 
 
 86-49 
 
 Kaiser. 
 
 Bavarian'Draught beer (Schenkbier] Munchen 
 Bavarian Store-beer (Lager-bier) Munchen ? 
 
 5-8 
 5-0 
 
 3-8 
 5-1 
 
 0-14 
 0-15 
 
 90-26 
 89-75 
 
 Kaiser. 
 Kaiser. 
 
 16 months old ... J 
 
 
 
 
 
 
 Bavarian Store-beer, MUnchen 
 
 3-9 
 
 4-3 
 
 0-16 
 
 91-64 
 
 Kaiser. 
 
 Bavarian Draught-beer, Brunswick 
 Bavarian Beer, Waldschlosschen . 
 
 5-t 
 4-8 
 
 3'5 
 3-6 
 
 Z 
 
 91-1 
 91-5 
 
 Otto. 
 Fischer. 
 
 Prague Draught-beer ... 
 Prague Town Beer (Stadt-bier) 
 
 6-9 
 10-9 
 14-0 
 
 2-4 
 3'9 
 l-6 
 
 
 
 90-7 
 85-2 
 84-7 
 
 Balling. 
 Balling. 
 Otto. 
 
 Josty's Beer Berlin ..... 
 
 2-6 
 
 2'6 
 
 0-5 
 
 94-3 
 
 Ziurek. 
 
 Werder's Brown Beer, Berlin . 
 
 3-1 
 
 23 
 
 0-3 
 
 94-2 
 
 Ziurek. 
 
 White Beer, Berlin ... 
 
 57 
 
 1-9 
 
 0-6 
 
 91-8 
 
 Ziurek. 
 
 Biere blanche de Louvain 
 
 3-0 
 
 4-0 
 
 _ 
 
 93-0 
 
 Le Carnbre. 
 
 Petermann, Louvain ... 
 
 4-0 
 
 6-5 
 
 
 
 89-5 
 
 Le Cambre. 
 
 
 45-0 
 
 1-9 
 
 
 
 53-1 J 
 
 Freytag and 
 Busse. 
 
 
 The following are examples of the percentage composition of the ash of beer, the first 
 three analysed by Walz (Jahrb. pr. Pharm. iii. 312 ; Jahresber. f. Chem. 1855, p. 892), 
 the rest by Dickson (PhiL Mag. xxxiii. 341; Jahresber. 1847-8, p. 1112). 
 
 TABLE E. Ash of Beer. 
 
 
 Ijmdon 
 Beer. 
 
 From 
 Munchen. 
 
 From 
 Spejer. 
 
 Scotch Ale 
 (14 samples). 
 
 Scotch 
 Porter 
 (2 samples). 
 
 Dublin 
 Porter 
 (2 samples). 
 
 London 
 Porter 
 (5 samples). 
 
 Potash .... 
 
 38-35 
 
 36-58 
 
 37-68 
 
 3-229-8 
 
 18-920-9 
 
 21-432-0 
 
 4-9 31-1 
 
 Soda .... 
 
 7-68 
 
 9-03 
 
 6-59 
 
 20-9 - 3-5 
 
 33-838-8 
 
 24-0427 
 
 21-8 50-8 
 
 Lime .... 
 
 2-45 
 
 1-48 
 
 2-98 
 
 0-2 2-0 
 
 1-3 1-6 
 
 08 1-5 
 
 0-8 6-9 
 
 Magnesia . . . 
 
 3-78 
 
 5-64 
 
 4-66 
 
 0-1 5-6 
 
 0-2 1-4 
 
 0-2 1-2 
 
 0-1 IS 
 
 Sulphuric acid (SO 3 ) . 
 Chlorine 
 
 1-36 
 2-75 
 
 1-68 
 3-14 
 
 2-56 
 2'14 
 
 1-6 )9'2 
 4-318-25 
 
 2-2 6-4 
 7-411-4 
 
 2-810-1 
 6-910-1 
 
 1-6 122 
 6-5 14-5 
 
 Silica .... 
 
 9-87 
 
 9-96 
 
 10-29 
 
 4-619 1 
 
 13-318-6 
 
 6-919-7 
 
 8.25197 
 
 Phosphoric acid (P2Q5) 
 
 33-76 
 
 31-69 
 
 33-10 
 
 6-025-7 
 
 12'5 -18-8 
 
 7-9 20'0 
 
 9 '3 20-6 
 
 
 100-00 
 
 10000 
 
 100-00 
 
 
 
 
 
 * The blanks in this column indicate that the carbonic acid was not determined quantitatively in the 
 corresponding samples. 
 
 MM 3 
 
534 
 
 BEER. 
 
 Original Gravity of Seer-worts. The conversion of sugar into alcohol by fer- 
 mentation, is attended with a diminution of density in the liquid; consequently the 
 specific gravity of beer is always less than that of the wort before fermentation. Now 
 by the revenue-laws of this country, the brewer is allowed a drawback upon all beer 
 that is exported, the amount being regulated according to the original gravity of the 
 wort. Hence it is necessary that the revenue officer be possessed of a method^ of 
 determining the original gravity, from the observed specific gravity and composition 
 of the beer, whereby he may check the record kept by the brewer. 
 
 If the non-volatile matter of beer consisted entirely of starch-sugar (glucose), the 
 determination of the original gravity would be a veiy easy matter : for it is found 
 that every 1 per cent, of alcohol in beer corresponds very nearly to 2 per cent, of 
 sugar in the wort before fermentation : hence it would merely be necessary to double 
 the percentage of alcohol in the beer, add thereto the percentage of sugar as found 
 by direct experiment, and the sum would be the total amount of sugar in 100 pts. of 
 the unfermented wort ; the specific gravity would then be given by a saccharometer- 
 table, such as Table B, p 532. 
 
 For example, London porter (No. 1, of Table D), contains 6*0 per cent, of malt- 
 extract (which we shall suppose to consist of starch-sugar), and 5 -4 per cent, alcohol, 
 the latter corresponding approximately to 10'8 per cent, starch-sugar. Hence the total 
 quantity of extract in the unfermented wort would be 6*0 + 10'8 = 16*8, giving a 
 specific gravity of 1*06. 
 
 But the actual problem to be solved is much less simple : for the wort contains 
 several other substances, all differing more or less in specific gravity from starch-sugar. 
 Hence the exact determination of original gravities can only be effected by special 
 observations. The question has been examined by several foreign chemists, especially 
 by Balling of Prague, in his great work on Brewing* ; in this country it has been 
 investigated by Messrs. Dobson and Phillips, of the Department of Inland Kevenue, 
 and more recently by Professors G-raham, Hofmann, and Eedwood, from whose 
 " Eeport on Original Gravities," f the following observations are extracted. 
 
 The substances contained in beer- wort, in addition to starch-sugar, are : 1. Dextrin, 
 which has not been converted into sugar in the process of mashing. 2. In many in- 
 stances, cane-sugar, the use of which is now permitted in breweries. 3. Caramel, 
 arising either from high-dried malt, or from treacle or burnt-sugar, the use of which 
 in the brewery of porter is also allowed by law. 4. A peculiar saccharine substance, 
 called " extractive substance," resembling caramel, possessing decided aeid properties, 
 and not fermentable by yeast, even after boiling with sulphuric acid.J 5. Azotised 
 or albuminous matter, derived from the grain. 6. Alkaline and earthy salts. 
 
 The albuminous matter and the inorganic salts, have but little effect on the com- 
 parative densities of the wort before and after fermentation ; but the dextrin, cane- 
 sugar, caramel, and " extractive matter," all give solutions of less specific gravity than 
 a solution of starch-sugar containing the same quantity of carbon, and therefore 
 capable of yielding an equal amount of alcohol. The differences are exhibited in the 
 following table. 
 
 TABLE F. Specific Gravities of Solutions of various SACCHARINE SUBSTANCES, and of 
 PALE and BROWN MALT containing equal quantities of CARBON. 
 
 
 
 
 
 
 
 
 Parts of Cane- 
 
 Solution 
 of Starch- 
 sugar. 
 
 Solution 
 of Cane- 
 sugar. 
 
 Solution 
 of 
 Dextrin. 
 
 Solution 
 of Extrac- 
 tive Sub- 
 stance. 
 
 Solution 
 of 
 Caramel. 
 
 Solution 
 of 
 Pale Malt. 
 
 Solution 
 of Brown 
 Malt. 
 
 sugar correspond- 
 ing in 1000 Parts 
 by Weight of 
 Solution. 
 
 1010-4 
 
 1010-1 
 
 1009-7 
 
 1008-9 
 
 1008-7 
 
 1010-0 
 
 1010-0 
 
 25 
 
 1020-8 
 
 1020-2 
 
 1019-3 
 
 1017-8 
 
 1017-3 
 
 1020-3 
 
 1020-2 
 
 50 
 
 1031-3 
 
 1030-2 
 
 1028-8 
 
 1026-5 
 
 1026-2 
 
 1030-6 
 
 1030-6 
 
 75 
 
 1042-4 
 
 1040-6 
 
 1038-3 
 
 1035-5 
 
 1034-9 
 
 1041-2 
 
 1041-2 
 
 100 
 
 1053-5 
 
 1051-0 
 
 1047-9 
 
 1044-7 
 
 1043-8 
 
 1052-1 
 
 1052-0 
 
 125 
 
 1064-9 
 
 1061-8 
 
 1057-3 
 
 1053-9 
 
 1052-8 
 
 1063-0 
 
 1062-9 
 
 150 
 
 1076-0 
 
 1072-9 
 
 1066-9 
 
 1063-0 
 
 1062-3 
 
 1074-2 
 
 1074-0 
 
 175 
 
 1087-8 
 
 1083-8 
 
 1067-6 
 
 1072-7 
 
 1071'8 
 
 1085-5 
 
 1085-5 
 
 200 
 
 1099-4 
 
 1095-2 
 
 1086-3 
 
 1082-3 
 
 1081-3 
 
 1097-2 
 
 1097-2 
 
 225 
 
 1111-4 
 
 1106-7 
 
 1095-8 
 
 
 1091-0 
 
 1109-0 
 
 1109-0 
 
 250 
 
 * Die Giihrungschemie wissenschaftlich begrundet und in ihrer Anwctidung avf die IVeinbercitung, 
 Bieibrauerei, Branntwcinbrennerei, und Hefenerzeugung prahtisch dargcstellt. Von C a r 1 N . Balling. 
 Prague, 1845. Or a shorter treatise by he same author : Die Saccharomctn'schc Bier- und Branntwein- 
 meischprobc. Prague, 1846. See also Handworterbuch d. Chem. 2te Aufl. ii. [!'] 1079. 
 
 t Chem. Sor. Q. J. v. 229. 
 
 t It probably contains glycerin and succinic acid, both of which substances have been shown by 
 Pasteur to be produced in alcoholic fermentation. 
 
BEER. 535 
 
 These numbers plainly show that if an unfermented wort contains cane-sugar and 
 dextrin, and the gravity lost by fermentation is inferred from the quantity of alcohol 
 contained in the beer, on the supposition that the fermentable matter consisted wholly 
 of starch-sugar, the estimated gravity will be too high ; and on the other hand the con- 
 version of a portion of the fermentable sugar into unfermentable extractive matter, which 
 gives a solution of lower specific gravity for the same amount of carbon, will cause 
 the estimate of the original gravity to come out too low; indeed, the extractive substance 
 indicates only about five-sixths of the saccharine principle from which it is derived. 
 
 To obviate these difficulties, the authors of the Eeport were led to propose,for the deter- 
 mination of original gravities, a purely empirical method, which consisted in ferment- 
 ing solutions of cane-sugar, starch, sugar, and malt-extract, of known original gravity, 
 and making, at ten or twelve stages of the process, two following observations : 1. Dis- 
 tilling a convenient quantity (4 fiuid ounces) of the fermented liquid in a retort as 
 described at page 530, diluting the alcoholic distillate with water, to the original 
 volume of the liquid, and taking its specific gravity ; this deducted from the specific 
 gravity of water (= 1000) gives the spirit-indication of the beer: e.g. if the 
 specific gravity of the alcoholic distillate after dilution is 985'95, the spirit-indication 
 is 14'05. 2. Diluting the boiled beer after cooling, to its original volume, taking its 
 specific gravity, and subtracting this, which is called the extract-gravity, from the 
 known original gravity of the wort before fermentation. The difference gives the 
 number of degrees of gravity lost, corresponding to the spirit-indication previously 
 observed. The results of a long series of determinations of this kind on liquids of 
 known original gravity are given in the " Eeport" in the form of tables : of these we 
 shall quote only those which embody the general result of the inquiry, and are 
 intended for actual use in determining the original gravity of beer- worts. 
 
 Table Gr (p. 536) is to be used when the spirit- indication of the beer is found by 
 distillation in the manner above-mentioned. The first column gives the integers of 
 spirit-indication, the fractional parts (tenths) thereof being placed at the heads of the 
 other columns ; the numbers in these several columns are the degrees of gravity lost 
 corresponding to the several spirit-indications. Thus, suppose that a sample of beer 
 distilled as above, gives a spirit-indication = 9'4, and extract-gravity = 1030'6. On 
 the ninth line of the table, and in the column headed -4, is found the number 41-2, 
 which is the gravity lost, and this added to the extract-gravity, gives 41 - 2 + 1030'6 
 = 1071 '8 for the original gravity of the wort. 
 
 As the distillation of the beer in a retort, and collecting of the entire quantity of 
 alcohol evolved, is an operation which occupies considerable time, and requires some 
 experience in manipulation, it is often desirable to obtain the spirit-indication of the beer 
 by an easier process. This may be done by first taking the specific gravity of the beer 
 deprived of carbonic acid by agitation, then boiling it in a flask till all the alcohol is 
 expelled, diluting it to its original volume, and again taking its specific gravity. The 
 first result, the beer-gravity, deducted from the second, the extract-gravity, is the 
 new spirit-indication : thus if the beer before boiling has a specific gravity of 10447, 
 and after boiling of 1035'!, the spirit-indication is 9'6 degrees. By numerous 
 experiments in which the beer was boiled in a retort, and the alcoholic distillate 
 collected as above, it was found that the second method, the evaporation-method, 
 gives a spirit-indication nearly equal to that resulting from the first or distillation- 
 method, but always sensibly less ; thus the spirit-indication of a particular sample was 
 9-9 degrees by the first method, and 9-6 by the second. The experiments in question 
 were made on liquids of known original gravity, and thus a series of determinations 
 were obtained of the relation between the spirit-indication as determined by the 
 evaporation-method, and the degrees of gravity lost. The general results of the 
 inquiry, as applied to malt- worts, are given in the Table H, the arrangement of which 
 is the same as that of Table Gr. 
 
 The authors of the Keport likewise suggest a rational method of determining 
 original gravities, which is interesting in a scientific point of view, though not expedi- 
 tious enough for practical use. It is as follows : First determine the amount of alcohol 
 in the beer by distillation. Then treat the residual liquid, which generally contains 
 both starch-sugar and unfermentable extractive matter, with yeast, to complete the 
 fermentation, and determine the additional quantity of alcohol thus produced, making 
 a correction for that which is introduced by the yeast itself. Lastly, make up the 
 remaining spiritless liquor with water to the original volume of the beer, and take its 
 specific gravity, a correction being also made for the increase of gravity caused by the 
 yeast. The quantity of starch-sugar corresponding to the corrected gravity of this 
 solution of extractive matter may now be found from a table provided for the purpose ; 
 and this, added to the amount of starch-sugar corresponding to the alcohol, gives the 
 total quantity of starch-sugar, from which the original gravity may be found by the 
 Baccharometer tables. 
 
 M M 4 
 
536 
 
 BEER. 
 
 TABLE G-. To be used in ascertaining Original Gravities by the DISTILLATION- 
 
 PEOCESS. 
 
 Degrees of Spirit-indication with corresponding Degrees of Gravity lost in Malt- 
 Worts. 
 
 Degrees of 
 
 
 
 
 
 
 
 
 
 
 
 Spirit- 
 
 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 indication. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 _ 
 
 0-2 
 
 0-6 
 
 0-9 
 
 1-2 
 
 1-5 
 
 1-8 
 
 2-1 
 
 2-4 
 
 27 
 
 1 
 
 3-0 
 
 3-3 
 
 37 
 
 4-1 
 
 4-4 
 
 4-8 
 
 5-1 
 
 5-5 
 
 5-9 
 
 6-2 
 
 2 
 
 6-6 
 
 7-0 
 
 7'4 
 
 7'8 
 
 8-2 
 
 8-6 
 
 9-0 
 
 9-4 
 
 9-8 
 
 10-2 
 
 3 
 
 10-7 
 
 11:1 
 
 11-5 
 
 12-0 
 
 12-4 
 
 12-9 
 
 13-3 
 
 13-8 
 
 14-2 
 
 147' 
 
 4 
 
 15-1 
 
 15-5 
 
 16-0 
 
 16-4 
 
 16-8 
 
 17-3 
 
 177 
 
 18-2 
 
 18-6 
 
 19-1 
 
 5 
 
 19-5 
 
 199 
 
 284 
 
 20-9 
 
 21-3 
 
 21-8 
 
 22-2 
 
 227 
 
 23-1 
 
 23-6 
 
 6 
 
 24-1 
 
 24-6 
 
 25-0 
 
 25-5 
 
 26-0 
 
 26-4 
 
 26-0 
 
 27-4 
 
 27-8 
 
 28-3 
 
 7 
 
 28-8 
 
 29-2 
 
 297 
 
 30-2 
 
 307 
 
 31-2 
 
 317 
 
 32-2 
 
 327 
 
 33-2 
 
 8 
 
 337 
 
 34-3 
 
 34-8 
 
 35-4 
 
 35-9 
 
 36-5 
 
 37-0 
 
 37-5 
 
 38-0 
 
 38-6 
 
 9 
 
 39-1 
 
 397 
 
 40-2 
 
 407 
 
 41-2 
 
 417 
 
 42-2 
 
 427 
 
 43-2 
 
 437 
 
 10 
 
 44-2 
 
 447 
 
 45-1 
 
 45-6 
 
 46-0 
 
 46-5 
 
 47-0 
 
 47-5 
 
 48-0 
 
 48-5 
 
 11 
 
 49-0 
 
 49-6 
 
 50-1 
 
 50-6 
 
 51-2 
 
 517 
 
 52-2 
 
 527 
 
 533 
 
 53-8 
 
 12 
 
 54-3 
 
 54-9 
 
 55-4 
 
 55-9 
 
 56-4 
 
 56-9 
 
 57-4 
 
 57-9 
 
 58-4 
 
 589 
 
 13 
 
 59-4 
 
 60-0 
 
 60-5 
 
 61-1 
 
 61-6 
 
 62-2 
 
 627 
 
 63-3 
 
 63-8 
 
 64-3 
 
 14 
 
 64-8 
 
 65-4 
 
 65-9 
 
 66-5 
 
 67-1 
 
 67'6 
 
 68-2 
 
 687 
 
 69-3 
 
 69-9 
 
 15 
 
 76-5 
 
 
 
 
 
 
 
 
 
 
 TABLE H. To be used in ascertaining Original Gravities by the EVAPORATION 
 
 PROCESS. 
 
 Degrees of Spirit-indication with corresponding Degrees of Gravity lost in Malt- 
 Worts. 
 
 Degrees of 
 
 Spirit- 
 indication. 
 
 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 
 
 _ 
 
 0-3 
 
 07 
 
 I'O 
 
 1-4 
 
 17 
 
 2-1 
 
 2-4 
 
 2-8 
 
 3-1 
 
 1 
 
 3-5 
 
 3-8 
 
 4-2 
 
 4-6 
 
 5*0 
 
 54 
 
 5-8 
 
 6-2 
 
 6-6 
 
 7-0 
 
 2 
 
 7-4 
 
 78 
 
 8-2 
 
 87 
 
 9-1 
 
 9-5 
 
 9-9 
 
 10-3 
 
 107 
 
 11-1 
 
 3 
 
 11-5 
 
 11-2 
 
 12-4 
 
 12-8 
 
 13-2 
 
 13-6 
 
 14-0 
 
 14-4 
 
 14-8 
 
 153 
 
 4 
 
 158 
 
 16-2 
 
 16-6 
 
 17'0 
 
 17-4 
 
 179 
 
 184 
 
 18-8 
 
 19-3 
 
 19-8 
 
 5 
 
 20-3 
 
 207 
 
 21-2 
 
 21-6 
 
 22-1 
 
 22-5 
 
 23-0 
 
 23-4 
 
 23-9 
 
 24-3 
 
 G 
 
 24-8 
 
 25-2 
 
 25-6 
 
 26-1 
 
 26-6 
 
 27-0 
 
 275 
 
 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 
 
 355 
 
 36-0 
 
 36-6 
 
 371 
 
 377 
 
 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 
 
 487 
 
 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 
 
 567 
 
 573 
 
 57-8 
 
 58-3 
 
 58-9 
 
 59-4 
 
 59-9 
 
 60-5 
 
 13 
 
 61-0 
 
 61-6 
 
 62-1 
 
 627 
 
 63-2 
 
 63-8 
 
 64-3 
 
 64-9 
 
 65-4 
 
 66-0 
 
 14 
 
 66-5 
 
 67-0 
 
 67'6 
 
 68-1 
 
 687 
 
 69-2 
 
 69-8 
 
 70-4 
 
 70-9 
 
 71-4 
 
 15 
 
 72-0 
 
 
 
 
 
 
 
 
 
 
 Adulteration of Beer. The addition of extraneous substances to beer, to give it 
 colour and heading, or to provide cheaper substitutes for the bitter of the hop, appears 
 to have been formerly carried to a great extent in this country. Dr. Ure says, in his 
 "Dictionary of Chemistry" 4th edition, 1831, p. 203 : "As long ago as the reign of 
 Queen Anne, brewers were forbid to mix sugar, honey, Guinea pepper, essentia bina, 
 cocculus indicus, or any other unwholesome ingredient, in beer, under a certain 
 penalty ; from which we may infer, that such at least was the practice of some ; and 
 writers, who profess to discuss the secrets of the trade, mention most of these, and 
 some other articles, as essentially necessary. The essentia bina is sugar boiled down 
 to a dark colour, and empyreumatic flavour. Broom tops, wormwood, and other bitter 
 plants, wore formerly used to render beer fit for keeping, before hops were introduced 
 into this country, but are now prohibited to be used in beer made for sale." 
 
BEER BELLADONNA. 537 
 
 " By the present law of this country, nothing is allowed to enter into the com- 
 position of beer, except malt and hops. Quassia and wormwood are often fraudulently 
 introduced; both of which are easily discoverable by their nauseous bitter taste. 
 They form a beer which does not preserve so well as hop beer. Sulphate of iron, 
 alum, and spit, are often added by the publicans, under the name of beer-heading, to 
 impart a frothing property to beer, when it is poured out of one vessel into another. 
 Molasses and extract of gentian root are added with the same view. Capsicum, 
 grains of paradise, ginger root, coriander seed, and orange peel, are also employed to 
 give pungency and flavour to weak or bad beer. The following is a list of some of the 
 unlawful substances seized at different breweries, and brewers' druggists' laboratories, 
 in London, as copied from the Minutes of a Committee of the House of Commons ; 
 cocculus indicus multum (an extract of the cocculus), colouring, honey, hartshorn 
 shavings, Spanish juice, orange-powder, ginger, grains of paradise, quassia, liqxiorice, 
 caraway seeds, copperas, capsicum, mixed drugs. Sulphuric acid is frequently added 
 to bring beer forward, or make it hard, giving to new beer instantly the taste of what 
 is eighteen months old." 
 
 This appears at first sight, a rather formidable picture of adulteration : nevertheless 
 most of the articles enumerated are perfectly harmless, and of those which are really 
 injurious, the use appears to have very much declined, partly perhaps in consequence 
 of the improved taste of consumers. Formerly there was a preference for what was 
 called good hard beer, that is to say beer in which nearly all the sugar and mucilage 
 had been converted into alcohol by fermentation : hence the use of sulphuric acid, 
 as above stated, to simulate the taste of beer thus advanced in fermentation. 
 With regard to burnt sugar or treacle, which is added to porter to give colour and 
 body, its use is now legalised, and therefore it can no longer be regarded as an 
 adulteration. 
 
 Picric acid and cocculus indicus are sometimes added to give bitterness to beer, 
 especially to bitter ale. The latter of these substances is especially objectionable, as 
 it contains a very poisonous substance, viz. picrotoxin. Picric acid may be detected 
 according to Lassaigne, by treating the liquid, evaporated to half or a quarter of its 
 bulk, with subacetate of lead, or shaking it up with powdered animal charcoal. Pure 
 beer is thereby almost wholly decolorised ; but if picric acid is present^ the filtered 
 liquid retains a lemon-yellow colour. This reaction is very delicate, sufficing to detect 
 1 part of picric acid in 12,000 to 18,000 parts of beer. Subacetate of lead likewise 
 precipitates the bitter principle of the hop, and thereby deprives pure beer of its 
 bitterness ; but beer containing picric acid remains bitter after being thus treated. 
 According to Pohl (Wien. Akad. Ber. xii. 88), a still more delicate test for picric 
 acid is obtained by immersing unbleached sheep's wool, or any fabric made there- 
 with, in the beer, boiling for six or ten minutes, and then washing the wool. If 
 the beer is pure, the wool remains white, but if picric acid is present, even to the 
 amount of only 1 pt. in 125,000, the wool then appears of a canary-yellow colour, pale 
 or dull according to the quantity. 
 
 Picrotoxin may be detected, according to T. J. Herapath, by mixing the beer with 
 excess of acetate of lead ; removing the lead from the filtrate by sulphuretted hydrogen ; 
 filtering again, boiling for a few minutes ; then slowly evaporating the solution till it 
 becomes thickish ; shaking it up with pure animal charcoal ; collecting the charcoal, 
 which contains the picrotoxin, on a filter; washing it with the smallest possible 
 quantity of water; then drying it at 100 C.; boiling it with alcohol; concentrating 
 the alcoholic filtrate ; and leaving it to evaporate. The picrotoxin then separates in 
 well defined quadrilateral prisms; or if the solution be rapidly concentrated, in 
 beautiful feathery tufts. (For figures of these crystals, see Muspratfs Chemistry, 
 i. 283.) 
 
 Inorganic substances added to beer will be found in the ash. Chalk is sometimes 
 added to sour beer to neutralise the acid ; in that case, the ash will contain more lime 
 than the normal quantity. If copperas has been added to promote the heading, the 
 liquid will give the reaction of sulphuric acid with chloride of barium, and the ash 
 will contain an abnormal quantity of oxide of iron. 
 
 BEGUIN'S VOXiATlIiE SPIRIT, Spiritus sidphuris Beguini, consists essen- 
 tially of sulphide of ammonium with excess of sulphur. 
 
 BEIiliADONCTA, OIXi OP. An oil expressed in Wurtemberg from the seed of 
 deadly nightshade (Atropa belladonna), and used for illumination and for culinary pur- 
 poses. It is limpid, of golden-yellow colour, of insipid taste, and without odour. Sp. gr. 
 0-9250 at 5 C. It thickens at - 16 C. and solidifies at - 25. The vapours which 
 it exhales during the _ process of extraction, intoxicate the workmen. The narcotic 
 principle, of the plant is retained in the marc, which cannot therefore be used as food 
 for cattle. (Gerh. ii. 881.) 
 
538 BELL ADONNINE BENZAMIDE. 
 
 B2SXiXf ADOXXCTXRTZ!. Ail alkaloid said to exist in Atropa belladonna. 
 BEX.Z.-METAXI ORE. See TIN PYRITES. 
 
 BEXiXHOHTTXir. A fatty substance prepared from Burmese naphtha. 
 BEXiONTTXi. KobelTs name for NEEDLE-ORE. 
 
 BEXQ*, OXIi OP. The oil expressed from the fruits of Moringa Ntix Behen, )esf. ; 
 Guilandina moringa Linn. ; or Moringa old/era Lam. It is colourless or slightly 
 yellow, of specific gravity 0*912, thick at 15 C., solid in winter. It is odourless, and 
 has a mild taste, is neutral to test-paper, and does not readily become rancid. It is 
 used in perfumery to extract the odorous principle of fragrant plants. In India it is 
 used as an embrocation for rheumatism. According to Volcker (Ann. Ch. Pharm. 
 Ixiv. 342), it is saponified perfectly by potash, 400 grammes yielding about 18 
 grammes of a mixture of solid fatty acids, together with oleic acid. The solid fatty 
 acids are : 1. An acid soluble in strong alcohol, insoluble in ordinary alcohol, melting 
 at 83 C. and containing 81*6 per cent, carbon and 13'8 hydrogen, numbers which 
 approximate to the formula C 45 H 90 2 ; but the quantity obtained was too small for 
 complete investigation. 2. Ordinary margaric acid. 3. An acid resembling stearic 
 acid, and called by Volcker, benic acid. 
 
 Another kind of oil of ben, said to be obtained from the seeds of Moringa aptera, 
 yields by saponification four fixed fatty acids, viz. stearic acid, margaric acid, and two 
 peculiar acids, benic acid and moringic acid. (Walter, Compt. rend. xxii. 1143.) 
 
 BEMTC ACID. This name has been applied to two different fatty acids, men- 
 tioned in the last article, both obtained from oil of ben, the one by Volcker, the other 
 by Walter. For distinction, Volcker's acid, which has the higher melting point, may 
 be called benostcaric acid, and Walter's benomargaric acid. 
 
 BENOMARGARIC Aero, C I5 H 30 2 , crystallises from its alcoholic solution in very bulky 
 nodules, melting at 52 Or 53 C. 
 
 Benomargarate of ethyl is very soluble in alcohol, and separates from the solution 
 in a crystalline mass. It melts at a very low temperature, even at the heat of the 
 hand. (Walter.) 
 
 BENOSTEARIC ACID, C 2I H 42 2 according to Volcker, C 22 H 44 8 according to Strecker 
 (Ann. Ch. Pharm. Ixiv. 346). The latter formula agrees with Volcker's analysis better 
 than the former. It is a white crystalline fat, melting at 76 C. and solidifying at 
 70 C. to a shining white crystalline mass, composed of needles, which may be rubbed 
 to powder; it is soluble in alcohol, and bears a strong resemblance to stearic acid. 
 
 Benostearate of sodium, C 22 H 4S Na0 2 , is obtained by saponifying the acid with car- 
 bonate of sodium, and dissolving the dried soap in absolute alcohol. The alcoholic 
 solution solidifies after a while to a gelatinous pulp, which is resolved into crystalline 
 grains by drenching it with a large quantity of alcohol. The barium-salt, C 22 H 43 Ba0 2 , 
 is precipitated on mixing an alcoholic solution of the sodium-salt with chloride of 
 barium. The lead-suit, C 22 H 43 Ba0 2 , is a white precipitate obtained by mixing the 
 soda soap with acetate of lead. 
 
 Benostearate of ethyl, C 22 H 43 2 .C'H 5 , is obtained by passing hydrochloric acid gas 
 through a solution of the acid in absolute alcohol. It is a crystalline mass, melting at 
 48 or 49 C. (Volcker.) 
 
 BENZAXiDIB-E. Syn. with hydride of benzoyl. See BENZOYL, HYDRIDE OF. 
 
 BENZAMXC ACID. Syn. with OXYBENZAMIC Aero (q. v.) 
 
 BEUZABIIDE. C 7 H 7 NO = N.C 7 H 5 O.H 2 . Nitride of Benzoyl and Hydrogen. 
 Liebig and Wohler, Ann. Ch. Pharm. iii. 268; Fehling, ibid, xxviii. 48 ; Schwarz, 
 ibid. Ixxv. 195; Laurent, Kev. Sclent, xvi. 391; Grerhardt, Traite, iii. Ixxv. 
 
 This body may bo obtained in various ways. 1. By the action of ammonia on bro- 
 mide, chloride, or cyanide of benzoyl. Chloride of benzoyl, when saturated with per- 
 fectly dry ammonia, evolves heat and solidifies into a white mass of benzamide and 
 chloride of ammonium, which must be repeatedly broken up, lest any chloride of ben- 
 zoyl be enclosed in it, and so escape the action of the ammonia. The sal-ammoniac is 
 extracted with cold water, and the benzamide crystallised from boiling water. Grer- 
 hardt prefers pounding chloride of benzoyl in a mortar, with excess of commercial car- 
 bonate of ammonium, heating the whole gently, extracting with cold water, and 
 crystallising the residue from alcohol or boiling water. Laurent prepares it by mixing 
 an alcoholic solution of chloride of benzoyl with aqueous ammonia. 2. By the action 
 of ammonia on benzoic anhydride. 3. By the action of ammonia on benzoate of ethyl. 
 The reaction takes place slowly at the ordinary temperature, more rapidly when the 
 ether is heated with aqueous ammonia over 100 C. in a sealed tube (Dumas). 4. By 
 boiling hippuric acid with water and peroxide of lead (Schwarz, Fehling); or by 
 heating it in a stream of dry hydrochloric acid. (Strecker.) 
 
BENZAMIDE. 539 
 
 When its hot aqueous solution is cooled suddenly, benzamide separates in small 
 pearly crystals, resembling those of potassic chlorate. When it is cooled slowly, it 
 solidifies into a mass of white shining needles, in which cavities form after a time, con- 
 taining one or more large crystals ; the transformation extends gradually through the 
 whole mass. The finest crystals are obtained from a solution containing a little 
 potash or ammonia. The crystals belong to the trimetric system. Benzamide is in- 
 odorous, almost insoluble in cold water, soluble in hot water (especially if it contains 
 ammonia), in alcohol, and in ether. It melts at 115 C., and solidifies on cooling to a 
 crystalline mass ; between 286 and 290 it volatilises undecomposed ; its vapour 
 smells slightly of bitter almonds, owing to the formation of some benzonitrile, is very 
 inflammable, and burns with a smoky flame. 
 
 When vapour of benzamide is passed through a red-hot tube, it is but slightly de- 
 composed, a small portion of a sweetish oil being formed, which, according to G-erhardt, 
 is benzonitrile. It is decomposed at a moderate heat, when passed through a tube 
 filled with pumice-stone, yielding hydrogen, nitrogen, carbonic oxide, and benzol 
 (Barreswil). Benzamide is not decomposed by cold caustic potash; but on boiling, 
 potassic benzoate is formed, and ammonia evolved. It is similarly decomposed by 
 boiling with strong acids, the solution on cooling depositing benzoic acid, while it re- 
 tains the ammonium-salt of the acid employed. When baryta is heated with benza- 
 mide, it undergoes a kind of fusion, and appears to be converted into hydrate of 
 barium ; ammonia is evolved, together with the oil which Gerhardt regards as benzo- 
 nitrile. Benzamide, heated with potassium, yields cyanide of potassium and benzo- 
 nitrile (cyanide of phenyl), but no ammonia. Heated with benzoic anhydride, or 
 chloride of benzoyl, it yields benzonitrile and benzoic acid : 
 
 C 7 H 7 NO + C 14 H 10 3 = 2C 7 H 6 2 + C 7 H 5 N 
 
 Benz. anhyd. Benz. acid. Benzonitrile. 
 
 C 7 H 7 NO + C 7 H 5 O.C1 = C 7 H 6 2 + C 7 H 5 N + HC1 
 
 Benzonitrile is also formed when benzamide is heated alone, or in a stream of dry 
 hydrochloric acid (Handw.) ; or treated with phosphoric anhydride or pentachloride of 
 phosphorus. Benzamide is not decomposed by boiling with water and peroxide of 
 lead ; but if hydrochloric or sulphuric acid be added, and the whole boiled, filtered, 
 mixed with ammonia, and exposed to the air, it turns brown, and deposits a mould- 
 like substance. 
 
 When benzamide is gently heated with fuming hydrochloric acid, it dissolves, con- 
 bining with the acid, and forming hydrochlorate of benzamide, C 7 H 7 NO.HC1, which 
 separates on cooling in long aggregated prisms. It is a very unstable compound ; the 
 crystals give off hydrochloric acid when exposed to the air, and in a few days have 
 become opaque, and lost the whole of their acid. (Dessaignes, Ann. Ch. Phys. [3] 
 xxxiv. 146.) 
 
 Benzamide is a primary amide, i. e. it represents 1 at. NH 3 in which 1H is replaced 
 by benzoyl. The remaining 2H may be wholly or partially replaced by a metal, or 
 an organic acid or basic radicle, secondary or tertiary amides or alkalamides being 
 formed. Those alkalamides which contain organic radicles are described under the 
 corresponding amine ; the amides and those of the alkalamides which contain a metal 
 will be described here. 
 
 Benzomcrcuramide. C 7 H 6 HgNO = N.C 7 H 5 O.Hg.H (Dessaignes, G-erhardt, 
 loc. cit,) Aqueous benzamide dissolves mercuric oxide abundantly, and the saturated 
 solution solidifies to a crystalline mass, which is coloured with excess of oxide. This 
 is treated with hot alcohol, and the solution on cooling deposits benzomercuramide in 
 white shining laminse, which may be washed and dried at 100 C. It is readily soluble 
 in alcohol and boiling ether. It is violently attacked by chloride of benozyl, yielding 
 benzoic acid, benzonitrile, and chloride of mercury. 
 
 Aqueous benzamide also dissolves small quantities of cupric and argentic oxides ; 
 but the compounds have not been examined. 
 
 Benzacetosulphophenamide. C 15 H 13 NS0 4 = N.C 7 H 5 O.C 2 H 3 O.C 6 H 5 S0 2 . Pro- 
 duced by the action of chloride of acetyl on benzosulphophenylargentamide. 
 
 Benzocumylsulphophcnamide, C 23 H 21 NS0 4 = N.C 7 H 5 O.C 10 H n O.C 6 H 5 S0 2 , is 
 obtained by the action of chloride of cumyl on benzosulphophenargentamide ; it crys- 
 tallises from ether in confused prisms. 
 
 Benzosalicylimide. C H H 9 N0 2 = N.C 7 H 5 O.C 7 H 4 0" (Limpricht, Ann. Ch. 
 Pharm. xcix. 250). Obtained by heating benzosalicylamic acid (benzosalicylamide) in 
 a small retort to 270 C., until about | has volatilised, and boiling the residue with 
 small quantities of alcohol, to remove the undecomposed acid. The pulverulent benzo- 
 salicylimide is dissolved in a larger quantity of boiling alcohol, whence it separates on 
 cooling in small yellowish needles. It is soluble in about 1000 pts. boiling alcohol. 
 
510 BENZ AMIDE. 
 
 Benzosulphophenamide. C 13 II"NS0 3 = N.C 7 H 5 O.C 6 H 5 S0 2 .H (Gerhardt and 
 Chiozza, Ann. Ch. Phys. [3] xlvi. 145). Obtained by heating equivalent quantities 
 of chloride of benzoyl and sulphophenamide to 140 145 C., as long as hydrochloric 
 acid is evolved. The fluid mass crystallises on cooling, and is recrystallised from 
 boiling alcohol. Forms shining, colourless, truncated, interlaced needles, which are 
 slightly soluble in cold water or ether, readily in alcohol. It has a strong acid reac- 
 tion, and is readily soluble in caustic alkalis. It melts between 135 and 140 C. ; 
 when quickly heated, it burns, gives off vapours of benzonitrile, and no longer solidifies 
 on cooling. Its ammoniacal solution becomes syrupy when gently evaporated, and 
 finally solidifies into a radiated mass, which Gerhardt states to be the acid ammonium- 
 salt of bcnsosulphophcnamic acid, C 26 H 29 N 3 S 8 8 = NH 3 .(C 13 H 13 NS0 4 ) 2 . This salt is 
 very soluble in water and alcohol, but insoluble in ether. When an acid is added 
 to its aqueous solution, an oily substance separates, which soon changes into needles 
 of benzosulphenamide. 
 
 Benzosulphophenamide, like many -other amides, behaves like a hydrate when acted 
 on by pentachloride of phosphorus, forming the chloride of a peculiar body, which 
 Gerhardt calls benzosulphophenamidyl. 
 
 C 13 H n NS0 3 + PCI 5 = C 13 H 10 NS0 2 .C1 + PG1 3 + HC1. 
 
 Chloride of benzo* 
 sulphophenamidyl. 
 
 The reaction does not take place till heat is applied. The new compound is decom- 
 posed by heat into benzonitrile and chloride of sulphophenyl. When it is tritu- 
 rated with carbonate of ammonium it forms an amide, benzosulphophenamidylamide, 
 N.C 13 H : NSO S .H 2 , which crystallises from alcohol, and is very slightly soluble in 
 ammonia. (Gerhardt, cited in Handw. ii. [1] 884.) 
 
 Benzosulphophenargentamide. C l3 H 10 AgNS0 3 =N.C 7 H 5 O.C 6 H 5 S0 2 .Ag. When 
 nitrate of silver is added to a boiling aqueous solution of benzosulphophenamide con- 
 taining a little ammonia, there is no precipitate ; but on cooling, this compound separates 
 out in colourless needles. It is but slightly soluble in cold water, readily in alcohol. 
 It is decomposed by heat, giving off sulphurous anhydride and benzonitrile, and leaving 
 a residue of metallic silver and carbon. Its solution in strong ammonia yields on eva- 
 poration, fine rose-coloured crystals, which contain the elements of 1 at. benzosulpho- 
 phenamide + 1 at. ammonia. They are readily soluble in boiling water ; the solution 
 on boiling deposits crystals of benzosulphophenargentamide ; the addition of an acid 
 separates benzosulphophenamide. Gerhardt regards this compound as a diamide, 
 N J .C 7 H 5 O.C 6 H 5 S0 2 .Ag.H 3 , a view which the absence of a diatomic radicle renders 
 improbable. 
 
 Benzosulphophenylsodamide. C 13 H 10 NaNS0 3 = KC 7 H 5 O.C 6 H 5 S0 2 .Na. Ben- 
 zosulphophenamide dissolves in sodic carbonate with evolution of carbonic anhydride ; 
 the solution is evaporated to dryness, and the residue exhausted with boiling alcohol, 
 which deposits the compound on cooling in opaque nodules. It is soluble in water ; 
 acids separate from it benzosulphophenamide. (Gerhardt, cited in Handw. ii. 
 [1] 884.) 
 
 Dibenzosulphophenamide. C 20 H 15 NS0 4 = N.(C 7 H 5 0) 2 .C 6 H 5 SO. (Gerhardt 
 and Chiozza, loc. cit.) Obtained by the action of chloride of benzoyl on benzosulpho- 
 phenargentamide. Chloride of silver is formed, together with a viscid mass, which 
 dissolves in ether, and crystallises in large brilliant prisms. It melts at 105 C., and 
 is slightly soluble in ammonia. It cannot be obtained by the action of chloride of 
 benzoyl on benzosulphophenamide. 
 
 Benzoyl enters into the composition of certain biamides and triamides, forming 
 compounds, which will be described under the original diamides and triamides 
 referred to. 
 
 Substitution-products of Benzamide. 
 
 Bromobenz amide is not known. Benzamide dissolves in bromine, without evo- 
 lution of hydrobromic acid ; the solution, after some days, deposits deep-red crystals, 
 having the composition C 7 H 7 NOBr', which may be regarded as the hydrobromate of 
 bromobenzamide, C 7 H 6 BrNO.HBr. The crystals are decomposed slowly by water, im- 
 mediately by ammonia, with separation of benzamide. (Laurent.) 
 
 Chlorobenzamide. C 7 H 6 C1NO = N.C 7 H 4 C10.H 2 (Limpricht and Uslar, 
 Ann. Ch. Pharm. cii. 263). Obtained by dissolving chloride of chlorobenzoyl in 
 strong aqueous ammonia ; the solution deposits yellow laminae of chlorobenzamide, 
 which are purified by recrystallisation from hot water or alcohol. It is insoluble in 
 cold water ; it fuses at 122 C., and sublimes in small quantities. The compound ob- 
 tained by Gerhardt and Drion (Ann. Ch. Phys. [3] xlv. 102), by triturating 
 chloride of chlorobenzoyl with carbonate of ammonium, has the same composition with 
 
BENZAMIL BENZENE. 541 
 
 the above, but differs from it slightly in properties, being insoluble in water, soluble 
 in alcohol or ammonia, . whence it crystallises in fine needles. It evolves ammonia 
 when boiled with potash. 
 
 Nitrobenzamide. C 7 H 6 N 2 3 = N.C 7 H 4 (N0 2 )O.H 2 . (Field, Ann. Ch. Pharm. 
 Ixv. 45. Chancel, Compt. Chim. 1849, 180.) Obtained in small quantity by fusing 
 nitrobenzoate of ammonium. Better, by adding aqueous ammonia to a solution of 
 nitrobenzoic ether in a rather large quantity of alcohol, and allowing the mixture to 
 stand for some days till it is not rendered turbid by water. It is then evapo- 
 rated on the water-bath till it crystallises on cooling ; and the crystals are purified 
 by recrystallisation from mixed alcohol and ether. It is also formed by the action 
 of ammonia on chloride of nitrobenzoyl. Nitrobenzamide is slightly soluble in 
 cold, readily in hot water; also in alcohol, ether, or wood-spirit. From these 
 latter solutions it crystallises in long needles, or, by slow evaporation, in large tables 
 resembling gypsum. It fuses above 100 C., and crystallises on cooling. When boiled 
 with strong potash, it forms potassic nitrobenzoate. Its aqueous solution is decom- 
 posed by sulphide of ammonium, as follows : 
 
 C 7 H 6 N 2 3 + 3 H 2 S = C'H 8 N 2 + 2H 2 + S 3 
 
 Pbenyl- 
 
 carbamide. 
 
 (Phenyl-urea.) 
 
 Dinitrobensamide. C 7 H 5 N 3 5 = N.C 7 H S (N0 2 ) 2 O.H 2 (Voit, Ann. Ch. Pharm. 
 xcix. 105.) When dinitrobenzoic ether is digested for some days with alcoholic 
 ammonia, it forms a blood-red solution, which deposits dinitrobenzamide in yellowish 
 laminae and prisms. It has a bitter taste, and dissolves sparingly in cold, more readily 
 in hot water; the solution is neutral. It melts at 183 C., and is decomposed by 
 further heat. Its ammoniacal solution is not precipitated by nitrate of silver. 
 
 Thiobenzamide. Schwefclbenzamid. Benzamide sulfure. C 7 H 7 NS = N.C 7 H 5 S.H a 
 (Cahours, Compt. rend, xxvii. 329). When a solution of benzonitrile in slightly 
 ammoniacal alcohol is saturated with sulphuretted hydrogen, the liquid becomes 
 brownish-yellow ; and if, after some hours, it is boiled down to its volume, and 
 water added, it deposits yellow flakes, which dissolve in boiling water, and separate 
 on cooling in long yellow silky needles of thiobenzamide. It is decomposed by mer- 
 curic oxide, yielding mercuric sulphide, water, and benzonitrile ; by potassium, 
 yielding potassic sulphide and cyanide. F. T. C. 
 
 BENZAftXXI.. C 28 H 20 N 2 2 (?) (Laurent, Eev. scient. xix. 446.) Crude 
 bitter-almond oil, shaken up with potash, is distilled till about has passed 
 over, the residue dissolved in ether-alcohol, and ammonia passed into the solution. 
 The deposit which forms is separated and boiled with a large quantity of ether ; and 
 the solution on cooling deposits silky crystals and a white powder : the latter is ben- 
 zamil. It is nearly insoluble in alcohol, difficultly soluble in ether. It melts at 170 C., 
 and solidifies very slowly. On dry distillation, it yields a substance soluble in ether. 
 It dissolves in alcoholic potash, and the solution, on cooling, deposits crystals which 
 have not been examined. F. T. C. 
 
 BECTZANXXiXDE. Syn. with Phenylbenzamide. See PHENYIAMIXE. 
 
 BENZEWE or BECTZOX., C G II 6 , or C n H?. Benzine, Hydride of phenyl, Bicarburet 
 of hydrogen. (Faraday, Phil. Trans. 1825, 440. Mitscherlich, Ann. Ch. Pharm. 
 ix. 39. Peligot, Ann. Ch. Phys. [2] Ivi. 59. Mansfield, Chem. Soc. Qu. J. i. 244.) 
 Discovered by Faraday. It is a product of the decomposition of many organic com- 
 pounds, being formed: 1. When benzoic acid is heated with caustic lime or baryta 
 (Mitscherlich), or when its vapour is passed over red-hot iron (Darcet, Ann. 
 Ch. Phys. [2] Ixvi. 99). 2. When phtalic acid is heated with caustic lime 
 (Marignac, Ann Ch. Pharm. xlii. 217), or insolinic acid with baryta (Hof- 
 mann). 3. By dry distillation of quinic acid (Wohler). 4. By passing vapour 
 of bergamot-oil over red-hot lime (Ohme, Ann. Ch. Pharm. xxxi. 318). 5. By 
 passing fats through red-hot tubes (Faraday). 6. By dry distillation of coal 
 (Hofmann, Mansfield). 7. In small quantity, when acetic acid or alcohol is 
 passed through a red-hot tube (Berthelot, Compt. rend, xxxiii. 210). It is also 
 found in Eangoon tar. ( D e La Eue and Miiller.) 
 
 The readiest method of preparing pure benzene, is to distil 1 pt. benzoic acid with 
 3 pts. slaked lime at a gently increasing heat ; the mixture of benzene and water which 
 passes over is shaken up with a little potash, the benzene decanted, dried over 
 chloride of calcium, and rectified on the water-bath. 3 pts. benzoic acid yield 1 pt, 
 benzene. The most abundant source of benzene is coal-tar ; but the product obtained 
 from this source is very impure, containing several higher hydrocarbons, volatile 
 -*d other substances. To obtain benzene pure, Mansfield shakes ur> tho 
 
542 BENZENE. 
 
 light oil obtained by the distillation of coal-tar with dilute sulphuric acid, then with 
 water, and then with potash, in order to remove all the acids and alkaloids that it 
 contains, and submits the washed oil to repeated fractional distillation ; the portion 
 which passes over at 80 90 C. is cooled to 12, when the benzene crystallises, 
 and is purified from liquid substances by pressure. A better method is to distil 
 the washed light oil in a metal still, and to pass the vapour upwards through a tube 
 surrounded with boiling water, and then into a cooled receiver ; thus the oils which 
 boil above 100 C. are condensed and run back into the still. The distillate is 
 similarly treated, the water round the condensing-tube being kept at 80 C. and the 
 distillation stopped when the heat in the retort rises to 90. This second distillate, 
 (only half of which solidifies at 20 ), is shaken up with i. vol. strong nitric acid, de- 
 canted, and shaken up with | vol. strong sulphuric acid, rectified without decantation, 
 and the product purified as before by cooling and pressure. Commercial benzene is 
 always very impure, containing many higher hydrocarbons ; it may be approximately 
 purified by distillation in the water-bath. 
 
 At the ordinary temperature, benzene is a limpid, colourless, strongly refracting 
 oil, of specific gravity 0-85 at 15-5 C. (Faraday, Mitscherlich), 0'8991 at 
 (Kopp). When cooled, it solidifies into fern-like tufts, or into hard masses like 
 camphor, which melt at 5'5 C., expanding in bulk at the same time, and solidify 
 again at 0. At 18, it is hard, brittle, and of specific gravity 0-956. It boils at 
 80-4 at 776 mm. (Kopp), at 86 (Mitscherlich), and volatilises undecomposed. 
 Its vapour- density is (expt.), 277 (calc.), 2'704. It has a pleasant smell. It is 
 scarcely soluble in water, but imparts a strong odour to it ; readily soluble in alcohol, 
 ether, wood-spirit, and acetone. It dissolves sulphur, phosphorus, and iodine, espe- 
 cially on heating; fixed and volatile oils, camphor, wax, mastic, caoutchouc, and 
 gutta-percha, abundantly ; gum-lac, copal, anime, and gamboge, in small quantity ; 
 quinine, somewhat readily ; strychnine and morphine in small quantity ; cinchonine, 
 not at all (Mansfield). Impure benzene is much used to remove stains from 
 silk, &c. 
 
 Benzene is very inflammable, and burns with a bright smoky flame. A mixture of 
 1 vol. benzene with 2 vols. alcohol of 0'85, forms a very good lamp-oil; a larger pro- 
 portion of benzene gives a smoky flame. When vapour of benzene is passed through 
 a red-hot tube, carbon is separated, and a gaseous hydrocarbon formed. Chlorine and 
 bromine (not iodine), act upon it in the sunshine, forming substitution-products (see 
 below). Strong nitric acid converts it into nitrobenzene ; according to Abel, the same 
 result is obtained by repeated distillation with dilute acid. Sulphuric anhydride or 
 fuming sulphuric acid converts it into sulphobenzide and sulphophenylic acid ; strong 
 non-fuming sulphuric acid into the latter product only (Grerhardt). According to 
 Mansfield and Mitscherlich, the non-fuming acid has no action upon it. Potassium, 
 aqueous alkalis, and pcrchloride of phosphorus, do not act upon benzene, even when 
 heated to its boiling point; neither does aqueous chromic acid (Abel), or phosgene 
 gas in sunshine. (Mitscherlich.) 
 
 Church (Phil. Mag. [4] xiii. 415) describes, under the name of Parabcnzcne, a 
 hydrocarbon obtained by him from the light oil of coal-tar, which is isomeric with 
 benzene, but has a different smell, boils at 97'5 C. and does not solidify at -20. 
 Nitric acid converts it into nitrobenzene ; fuming sulphuric acid into an acid isomeric 
 with sulphophenylic acid, but whose copper- and barium-salts are somewhat different 
 in properties from those of that acid. 
 
 Hofmann (Ann. Ch. Pharm. Iv. 201) gives a good process for the detection of 
 benzene in a mixture of volatile oils, founded on the facility with which benzene is 
 converted into nitrobenzene by nitric acid, and nitrobenzene into phenylamine by 
 reducing agents. The liquid to be examined is warmed in a test-tube with fuming nitric 
 acid, diluted with water, and shaken up with ether, which dissolves the nitrobenzene. 
 The ethereal solution is separated by a pipette, and mixed with equal volumes of 
 alcohol and hydrochloric acid, and granulated zinc added. After five minutes, the 
 mixture is saturated with potash, again shaken up with ether, which dissolves the 
 liberated phenylamine, and the ethereal solution evaporated on a watch-glass ; the 
 addition of a drop of hypochlorite of calcium to the residue gives the intense purple 
 colour characteristic of phenylamine. 
 
 Substitution-products of Benzene. 
 
 Bromine dissolves in benzene, forming compounds in which 1, 2, and 3 at. H are 
 respectively replaced by Br. 
 
 Bromobenzene. Monobromobenzid. Bromide of phenyl, C 6 H 5 Br (Co up or, 
 Ann. Ch. Phys. [3] lii. 309). The vapour of an equivalent quantity of bromine is 
 passed into a large- flask in which some benzene is heated to boiling; the product is 
 
BENZENE. 543 
 
 washed with potash, dried, and distilled ; most of it passes over about 150 C. It is a 
 colourless liquid, smelling like benzene ; it does not solidify at 20 C. ; its vapour- 
 density is 5-631. It is not decomposed when heated to 200 C. with acetate of silver, or 
 with a solution of sulphate of silver in strong sulphuric acid. Heated with potassium 
 in a sealed tube, it explodes ; with sodium, it yields benzene and a crystalline body. 
 Fuming nitric acid converts it into bromonitrobenzene, C 6 H 4 BrN0 8 , a crystalline body 
 which melts below 90, and distils undecomposed. Fuming sulphuric acid dissolves it, 
 forming bromosiilpJiophenylic acid. 
 
 Dibromobcnzene. Bibromobenzid. C G H 4 Br 2 (Couper, loc. cit.} When mono- 
 "bromobenzene is acted on for some time by excess of bromine, hydrobromic acid is 
 SA r olved, and crystals separate, which, by recrystallisation from ether, are obtained in 
 large oblique prisms, which melt at 89 C. and boil at 219 without decomposition. 
 
 Tribromobenzene. Terbromobenzid. C'^Br 3 (Mitscherlich (1835), Pogg. 
 Ann. xxxv.374. Lassaign e, Rev. scient. v. 360). A mixture of benzene and bromine 
 exposed to sunlight gradually forms a solid crystalline body, which is purified by 
 washing with boiling ether. This is the hydrobromate of tribromobenzcnc, C^IPBr 6 
 C 6 H 3 Br 3 .3HBr. It forms a white inodorous tasteless powder, insoluble in water, 
 sparingly soluble in boiling alcohol or ether, whence it crystallises in microscopic 
 oblique rhombic prisms. It is fusible, and crystallises on cooling. When heated, it 
 partly sublimes undecomposed, and is partly resolved into tribromobenzene, hydro- 
 bromic acid, bromine, and hydrogen Heated with hydrate of calcium, it yields tri- 
 bromobenzene. This compound is best obtained by boiling the hydrobromate with 
 alcoholic potash, adding water, dissolving the precipitated oil in ether, and evaporating 
 the solution ; it forms silky, very fusible needles, soluble in alcohol and ether, and 
 volatile without decomposition. 
 
 Monochlorobenzene. See PIIENYL, CHLORIDE or. 
 
 Trichlorobenzene. Chlorobcnzid. C 6 H 3 C1 3 (Mitscherlich, loc. cit. Pe"ligot, 
 Ann. Ch. Phys. [2] Ivi. 66. Laurent, ibid. Ixiii. 27). The action of chlorine in 
 sunshine upon benzene is similar to that of bromine, resulting in the formation of 
 crystals of hydrochlorate of trichlorobenzene, C 6 H 6 C1 6 = C 6 H S C1 3 .3HC1, which are 
 washed with ether or recrystallised from boiling alcohol. It forms colourless shining 
 laminse, or rhombic prisms with truncated lateral edges, insoluble in water, soluble in 
 alcohol or ether: melts at 132 C. (Mitscherlich); 135 140 (Laurent) ; distils 
 completely at 288, with partial decomposition, without leaving any residue. In its 
 decompositions, it resembles the corresponding bromine compound. Trichlorobenzene 
 is obtained by the repeated distillation of the hydrochlorate alone (Mitscherlich); 
 or by heating it with hydrate of barium or calcium, washing the distillate with water, 
 and rectifying it over chloride of calcium; or by boiling it with alcoholic potash 
 (Laurent). It is a colourless oil, of specific gravity 1*457 at 7 C. ; boils at 210; 
 vapour-density 6 -37 ; insoluble in water, soluble in alcohol, ether, or benzene. It is 
 not attacked by chlorine, bromine, acids, or alkalis. 
 
 Chlorodinitrobenzene. See CHLORIDE OF DINITROPHENYL, under PHENYL, 
 CHLORIDE OF. 
 
 Nitrobenzene. Nitrobenzol. Nitrobenzid. C 6 H 5 N0 8 (Mitscherlich (1834), 
 Pogg. Ann. xxxi. 625). Formed by the action of fuming nitric acid on benzene, or by 
 the dry distillation of nitrobenzoates. Prepared by gradually adding benzene to warm 
 fuming nitric acid ; the nitrobenzene separates as an oil on cooling, is washed with 
 water, and rectified over chloride of calcium. It is a yellowish liquid, with a very 
 sweet taste, and a smell like bitter-almond oil; specific gravity 1-1866 at 14'4C. 
 (Kopp); boils at213C. (Mitscherlich), 219 220(Kopp); vapour-density 4-4. 
 Below 3 C. it crystallises in needles. It is insoluble in water, readily soluble in 
 alcohol and ether. It is much used by perfumers, under the name of Essence de mir- 
 bane. It is not attacked either by chlorine or bromine at the ordinary temperature ; 
 but its vapour is decomposed when passed with chlorine through a red-hot tube, yield- 
 ing hydrochloric acid. Fuming nitric acid dissolves it, and on heating converts it 
 into dinitrobenzene. Strong sulphuric acid dissolves it, and on heating decomposes 
 it, forming a dark- coloured solution, and evolving sulphurous anhydride. Dilute 
 nitric or sulphuric acid does not attack it, even at 100C. It is scarcely attacked by 
 boiling with aqueous potash or ammonia, or by distillation over caustic lime ; when 
 boiled with alcoholic potash, it yields azoxybenzide (p. 479) ; and when distilled with 
 alcoholic potash, azobenzide. When a solution of nitrobenzene in alcohol is mixed 
 with ammonia, and saturated with sulphuretted hydrogen, sulphur is deposited, and the 
 product, when cooled to C., solidifies to a mass of yellow needles, which are soluble 
 in water or alcohol and have a biting taste ; on driving off the alcohol by heat, more 
 sulphur is deposited, and phenylamine is finally left : 
 
 C a H 5 N0 2 + 3H 2 S = C 6 H 7 N + 2H 2 + S 3 . 
 
544 BENZHYDRAMIDE BENZIDINE. 
 
 Other reducing agents, c. g, zinc with a mixture of alcohol and hydrochloric acid, 
 iron filings and acetic acid, and arsenite of potassium, convert nitrobenzene into 
 phenylumine. 
 
 Dinitrobenzene. C 6 H 4 N 2 4 = C 6 H 4 (N0 2 ) 2 (Devill* (1841), Ann. Ch. Phys. 
 [3] iii. 187. Muspratt and Hofmann, Ann. Ch. Pharm. Ivii. 214). Formed very 
 slowly by boiling nitrobenzene with fuming nitric acid ; rapidly when nitrobenzene is 
 dropped gradually into a mixture of equal vols. fuming nitric and strong sulphuric 
 acid as long as solution takes place. The mixture is boiled for some minutes, and the 
 crystalline magma which forms on cooling is washed with water and recrystallised 
 from boiling alcohol. It forms long shining needles or lamina;, which melt below 
 100 C. and solidify into a radiated mass. It is insoluble in water, soluble in warm 
 alcohol Sulphide of ammonium converts it into nitrophenylamine, and separates 
 sulphur. Zinc and hydrochloric acid convert it into nitrosophenylin (q. v.} Accord- 
 ing to Hilkenkamp (Ann. Ch. Pharm xcv. 86), sulphite of ammonium converts 
 it into a peculiar acid, dithiobcnzolic or phenyldisulphodiamic acid, C 6 H 8 N 2 S 2 6 . He 
 obtained this compound by the action of sulphite of ammonium on nitrobenzene, as 
 follows ; but he attributes its formation to the presence of dinitrobenzene. He heated 
 80 grms. nitrobenzene with 240 grms dry sulphite of ammonium, 1 litre absolute alcohol, 
 and some carbonate of ammonium, for 8 or 10 hours on a water- bath. The liquid was 
 filtered from the sulphate of ammonium which separated on cooling, and evaporated to 
 a syrup, when it deposited at first abundance of fine white lamina?, which quickly 
 decomposed, and then a smaller quantity of hard needles, which are the ammonium- 
 salt of this acid. 
 
 6S0 3 N 2 H 8 = C 6 HN 2 S 2 6 + 4S0 4 N 2 H 8 + 4NH 3 . 
 
 Dinitrobenzene. Dithiobenzolic 
 
 acid. 
 
 It is readily soluble in water or dilute alcohol, slightly in absolute alcohol, insoluble 
 in ether. Nitric acid colours its solution yellow ; chlorine forms with it abundance 
 of chloranil, with traces of a brown resinous substance. The barium- salt is crys- 
 talline, soluble in water, insoluble in alcohol. The acid has not been obtained in the 
 free state. F. T. C. 
 
 BEKTZHYDRAMIDE. Hydride of Cyanazobenzoyl. C 22 H 18 N 2 (Laurent, 
 Ann. Ch. Phys. [2] Ixvi. 180; Laurent and Gerhardt, Compt. Chim. 1850, 114). 
 A product of the action of ammonia on crude bitter-almond oil ; or of cyanide of 
 ammonium on hydride of benzoyl. 
 
 3C 7 H 6 + NH 4 CN = C 82 H 18 N 2 + 2H 2 0. 
 
 Crude bitter- almond oil heated to 100 C., is saturated with dry ammonia, and the 
 product dissolved in ether-alcohol: after twenty-four hours, the solution begins to 
 deposit crystals, which go on increasing for three or four days. The mother-liquor is 
 decanted, and the crystals treated with boiling alcohol, which leaves a white residue, 
 benzoylazotidc. The solution, on spontaneous evaporation, deposits small needles, mixed 
 with drops of oil : these are washed quickly with a little ether-alcohol, and recrys- 
 tallised from boiling alcohol. It is also formed in the process for the preparation of 
 azobenzoyl (q. ?;.) 
 
 Benzhydramide forms colourless, microscopic, rectangular prisms, with two terminal 
 faces intersecting at an obtuse angle. It is insoluble in water, sparingly soluble in cold 
 alcohol, readily in hot alcohol or in ether. It is very fusible, and solidifies on cooling 
 to a resinous mass, without decomposition : when further heated, it gives off hydro- 
 cyanic acid, and yields an oil, a crystalline sublimate, and a little carbon. It is not 
 decomposed by cold dilute hydrochloric acid ; but, on boiling, it yields hydride of 
 benzoyl, hydrocyanic acid, and chloride of ammonium. F. T. C. 
 
 BENZHYDROCY ATJIDE. Syn. with BENZIMIDE (q. v.} 
 
 BENZHYDROXiXC ACID. Kochleder and Hlasiwetz gave 
 
 the name of benzhydrol to a camphor obtained by them from oil of cassia. Further 
 investigation by Rochleder and Schwarz, has shown that this camphor contains two 
 substances, one richer in hydrogen, the other in oxygen : they call the former benzhy- 
 drol, the latter, benzhydrolic acid. F. T. C 
 
 BENZXDAXVX. Syn. with PHENYLAMINE (q. v.) 
 
 BENZIDINE. C 12 H 12 N 2 = N 2 .C 12 H 8 .H 4 (Zinin, J. pr. Chem. xxxvi. 93; Ivii. 
 173 ; Ann. Ch. Pharm. Ixxxv. 328.) An organic alkali formed by the reduction of 
 azobenzene or azoxybenzene. It is obtained by saturating with sulphuretted hydrogen 
 a solution of azobenzene in alcoholic ammonia: the liquid turns brown, and, when 
 heated, deposits sulphur abundantly, which is filtered off The filtrate, on cooling, 
 deposits crystals of benzidine, which are purified by dissolving them in boiling alcohol, 
 
BENZIDINE BENZIL. 5 [5 
 
 adding dilute sulphuric acid as long as a precipitate forms, washing the precipitate with 
 alcohol, and dissolving it in boiling aqueous ammonia : the solution, on cooling, deposits 
 benzidine in white shining scales. When an alcoholic solution of azobenzene or azoxy- 
 benzene is treated with sulphurous acid, sulphate of benzidine is at once precipitated. 
 
 Benzidine is inodorous ; scarcely soluble in cold water, readily in hot water, alcohol, 
 or ether ; its solution has a bitter burning taste. It melts at 108 C., and cools to a 
 crystalline mass : further heated, it partly sublimes, and is partly decomposed. When 
 a solution of benzidine, or its salts, is treated with chlorine, it becomes first blue, then 
 dark brown, and deposits scarlet crystals, scarcely soluble in water, more readily in 
 alcohol (probably azobenzene). Nitrous fumes attack it violently at a gentle heat, 
 and convert it into azobenzene (Noble). It is decomposed by strong nitric acid. 
 
 Benzidine combines with acids, forming definite salts, which are mostly readily 
 crystallisable : their solutions are precipitated by caustic alkalis or alkaline carbonates. 
 The hydrochlorate, C 12 H 12 N 2 .2HC1, crystallises in white, pearly, rhombic prisms, 
 soluble in water or alcohol, almost insoluble in ether. The chloroplatinate, 
 C 12 H 12 N*.2PtCl 3 H, is a yellow crystalline precipitate, obtained by adding dichloride of 
 platinum to the aqueous or alcoholic solution of the foregoing salt. It is slightly 
 soluble in water, insoluble in alcohol or ether. When boiled with water (more readily 
 with alcohol or ether), it is converted into a dark-violet powder. The nitrate forms 
 rectangular prisms, soluble in water. The acid oxalate, C 12 H 12 N 2 .C 2 4 H 2 , forms 
 white, silky, radiated needles, slightly sohible in water or alcohol. The acid sulphate, 
 C 12 H I8 N 2 .S0 4 H 2 , separates as a dull white powder, when sulphuric acid is added to a 
 solution of benzidine : from a very dilute solution it separates in crystals. It is scarcely 
 soluble in boiling water or alcohol. The benzoate, acetate, tartrate, and phosphate are 
 all crystalline. With mercuric chloride, benzidine forms a crystalline double-salt, 
 soluble in water and alcohol. F. T. C. 
 
 Diethylbcnzidine, C la H 20 N 2 = N 2 .C 12 H 8 ". (C 2 H 5 ) 2 .H 2 . The hydriodate of this base, 
 CioH-'N^HI) 2 , or iodide of diethyl-binzidammonium [N 2 .(C 12 H 8 )''(C 2 H 5 ) 2 .H 4 ].I 2 , is 
 obtained in crystals by digesting benzidine with alcohol and iodide of ethyl, in a 
 sealed tube at 100 C. for two hours. Treated with ammonia, it yields the free 
 base, which unites with acids forming well crystallised salts. The chloroplatinate, 
 C 16 H 22 C1 2 . 2PtCl 2 is sparingly soluble. (P. W. Hofmann, Proc. Eoy. Soc. xv. 585; 
 Ann. Ch. Pharm. cxv. 362.) 
 
 Tetrethylbenzidine, C 20 H 28 N 2 = N*.(C 12 H 8 )".(C 2 H 5 ) 4 , is obtained as a hydriodate by 
 treating the diethylated base with iodide of ethyl. The free base melts at 83 C. re- 
 solidifies at 80, and forms crystalline salts with acids. Iodide of ethyl acts but 
 slowly on it, but when treated with iodide of methyl, attacks it with energy, forming : 
 
 Iodide of Dimethyl-tetrethyl-benzidammonium, C 22 H 34 N*I 2 = [N 2 .(C 12 H 8 )".(C*H 5 ) 4 . 
 (CH 3 ) 2 ].! 2 . This salt dissolves sparingly in alcohol, but easily in boiling water, 
 whence it crystallises in long beautiful needles. Its solution is not precipitated by 
 ammonia, but yields with oxide of silver, a strongly alkaline solution containing the 
 
 hydrate N ^ C1 H5 )^ C g7|o 2 . This base unites readily with acids, forming 
 
 beautifully crystalline salts. The chloroplatinate C 22 H 34 N 2 Cl 2 .2PtCl 2 , is almost in- 
 soluble in water, but dissolves sparingly in boiling hydrochloric acid, whence it 
 crystallises on .cooling in beautiful needles. (P. W. Hofmann, loc. cit.) 
 
 BENZIL. Sousoxide de Stilbese, C 14 H'0 2 . (Laurent. Ann. Ch. Phys. [2] lix. 
 402. Liebig. Ann. Ch. Pharm. xxv. 25. Zinin, Ann. Ch. Pharm. xxxiv. 190. 
 Gregory, Compt. Chim. 1845. 308.) Formed by the action of oxidising agents on 
 benzoin. Laurent prepares it by passing chlorine over fused benzoin as long as hydro- 
 chloric acid is evolved, and crystallising the product from hot alcohol. Zinin heats 
 gently 1 pt. benzoin with 2 pts. concentrated nitric acid ; the reaction is complete when 
 no more nitrous fumes are evolved, and when the yellow oil which rises to the surface 
 is quite clear. This oil solidifies to pure benzil on cooling. 
 
 It crystallises by spontaneous evaporation of its alcoholic or ethereal solution in long 
 yellowish six-sided prisms, which are commonly hollow. Observed faces, oo P . oP . P. 
 It is without smell or taste, insoluble in water, soluble in alcohol, ether, and warm sul- 
 phuric acid, and reprecipitated from the last by water. It fuses between 90 and 92 C. 
 and solidifies to a fibrous mass : at a higher temperature, it volatilises undecomposed. 
 
 It burns with a red sooty flame. It is not altered by boiling with nitric acid or 
 with aqueous potash : but when boiled with alcoholic potash, it turns blue and forms 
 benzilic acid. With ammonia, an alcoholic solution of benzil forms various products, 
 according to the concentration and the duration of the reaction (see AZOBENZIL) 
 BENZELAM, BENZTLIM, IMABENZIL). With sulphuretted hydrogen, it deposits sulphur, 
 and forms a yellow oil, smelling of garlic : this oil is more readily obtained by dis- 
 tilling benzil with alcoholic sulphide of ammonium. With sulphide of ammonium, it 
 
 VOL. I. N N 
 
546 BENZILAM BENZILIM. 
 
 yields two or three different products, among which is hydrobemil (a. v.) Fused witli 
 potassium, it gives off violet vapours and leaves a carbonaceous residue. 
 
 Benzil is polymeric with the hypothetical radicle benzoyl, C 7 H 5 0. 
 
 Hydrocyanate of Benzil. C 16 H 12 N 2 2 = C"H 10 2 ,2HCy (Zinin). When benzil 
 is dissolved in boiling alcohol, and an equal weight of nearly anhydrous prussic acid 
 is added, the mixture gradually deposits white shining rhombic tables of hydrocyanate 
 of benziL This compound melts and decomposes when heated, leaving pure benzil. 
 It is not attacked when boiled with water or strong hydrochloric acid : when heated 
 with nitric acid or ammonia, it yields benziL Its alcoholic solution gives with nitrate 
 of silver a precipitate of cyanide of silver, and benzil crystallises from the solution. 
 When its alcoholic solution is heated with mercuric oxide, mercury is reduced, and the 
 smell of benzoic ether becomes distinctly perceptible. F. T. C. 
 
 BENZILAM. C H H 9 N. (Laurent, Eev. scient, xix. 443.) Formed, together 
 with imabenzil and benzilim, by the action of ammonia on benzil. It is best pre- 
 pared by dissolving imabenzil or benzilim in sulphuric acid, and adding water, 
 when an oil separates out which speedily solidifies : this is washed with water and 
 a little alcohol, and crystallised from ether-alcohol. It forms colourless rhombic 
 prisms readily soluble in alcohol or ether. It melts at 105 C. : if imperfectly fused, 
 it quickly crystallises on cooling, but if perfectly fused, it solidifies much more slowly, 
 without crystallisation. It is volatile without decomposition. Boiling alcoholic 
 potash has no action upon it : nitric acid decomposes it, yielding an oil which crystal- 
 lises on cooling, and is insoluble in ether : it is soluble in sulphuric acid, and is repre- 
 cipitated by water. F. T. C. 
 
 BEKTZILIC ACID. Stilbic Acid. C 14 H 12 3 . (Liebig [1838], Ann. Ch. Pharm. 
 xxv. 25. Zizin, ibid. xxxi. 329.) Formed by the action of alkalis on benzil or 
 benzoin. Benzil is dissolved in boiling alcoholic potash, in such quantity that the 
 solution remains distinctly alkaline, and the whole is boiled until a sample of it gives 
 no turbidity when mixed with water. The solution is then evaporated to dryness on 
 the water-bath, the residue powdered, and exposed to an atmosphere of carbonic anhy- 
 dride till all the potash is converted into carbonate ; it is then extracted with alcohol, 
 the solution mixed with water, and, after distilling off the alcohol, decolorised with 
 animal charcoal, and evaporated to crystallisation. The potassic benzilate thus ob- 
 tained is redissolved in water, and mixed with boiling dilute hydrochloric acid : on 
 cooling, benzilic acid crystallises out. 
 
 It forms hard, shining, colourless needles, which are sparingly soluble in cold, more 
 readily in hot water, easily in alcohol or ether. It has no smell, a bitter metallic 
 taste, and a strong acid reaction. It melts at 120 C. ; when heated more strongly, 
 it turns red, and emits violet vapours which condense to a brown-red oily liquid, a 
 residue of carbon being left. This oil is volatile, insoluble in water, soluble with a 
 red colour in alcohol or ether : the solution is not decolorised by water, or by hydro- 
 chloric or sulphuric acid, but it is decolorised by potash, ammonia, or nitric acid. 
 Benzilic acid burns with a very smoky flame. With strong sulphuric acid all 
 benzilates give a fine crimson colour, which is not easily destroyed by heat disappears 
 on adding water, but reappears on evaporation. It dissolves in warm nitric acid, and 
 is precipitated unchanged by water. Pentachloride of phosphorus converts it into 
 chlorobenzil. 
 
 Benzilates. Their general formula is C 14 H"M0 3 . The lead-salt is obtained by 
 adding the aqueous acid to neutral acetate of lead. It is a white powder, slightly 
 soluble in hot water : it is unalterable at 100 C., but when strongly heated melts to a 
 red liquid, and emits violet vapours. The potassium-salt forms colourless, transparent, 
 anhydrous crystals, readily soluble in water and alcohol, insoluble in ether. It melts 
 at 200 C., and solidifies on cooling : heated more strongly, it decomposes, yielding a 
 colourless oily distillate, smelling like naphthaline, insoluble in water, soluble in 
 alcohol; the residue contains carbon and potassic carbonate. The silver-salt is a 
 white, crystalline powder, obtained by precipitating nitrate of silver by the potassium- 
 salt. It is slightly soluble in hot water ; at 100 C. it turns blue, without losing weight, 
 and melts when further heated, emitting violet vapours and leaving metallic silver. 
 
 F. T. C. 
 
 BZSrzix,xzyx. BenzUimide. C 28 H 22 N 2 0- (Laurent [1845], Eev. scient. xix. 442). 
 One of the products of the action of ammonia on benzil. It is most easily obtained 
 pure by dissolving imabenzil in boiling alcoholic potash, and adding water to the 
 solution. It forms white, silky, very fine needles, sparingly soluble in alcohol or 
 ether. It melts at 130 C. and solidifies slowly in cooling to an amorphous mass. It 
 distils apparently undecomposed, but the distillate is readily soluble in ether, and 
 crystallises from it in needles. It is not attacked by boiling potash or by hydrochloric 
 acid : warm nitric acid attacks it, evolving red fumos, and yielding a yellow oil, which 
 
BENZIMIC ACID BENZOERETIC ACID. 547 
 
 crystallises on cooling, and is insoluble in ammonia, but soluble and crysfallisable 
 from ether. It dissolves in warm sulphuric acid, and the addition of water separates 
 benzilam. F. T. C. 
 
 BEHTZIAKIC ACID. (Laurent, Compt. Chim. i. 37.) The name given by 
 Laurent to a peculiar acid which is formed in the preparation of amarine (q. v.) It 
 is best prepared by saturating an alcoholic solution of bitter-almond oil with ammonia, 
 letting it stand for 48 hours, and adding water, which takes up benzimate of ammo- 
 nium. The addition of hydrochloric acid to the aqueous solution precipitates the 
 acid, which is purified by dissolving it in alcohol containing ammonia, boiling the 
 solution, and neutralising with hydrochloric acid. It forms white silky needles, 
 insoluble in water slightly soluble in alcohol : it melts when heated, and cannot be 
 distilled undecomposed. It has not been analysed. F. T. C. 
 
 BENZIIVIIDE. Benzhydrocyanide. Hydride of Cyanobenzoyl, C 23 H 18 N*0 2 . 
 (Laurent (1836), Ann. Ch. Phys. [2] lix. 397: Ixvi. 193; Kev. seient. x. 120. 
 Zinin, Ann. Ch. Pharm. xxxiv. 188. Gregory ibid. liv. 372. Laurent and 
 Gerhardt, Compt. chim. 1850, 116.) Formed by the action of hydrocyanic acid on 
 hydride of benzoyl : 
 
 3C 7 H 6 + 2CNH = C 23 H 18 N 2 2 + H 2 0. 
 
 Hydride of benzoyl mixed with i its volume of nearly anhydrous prussic acid is 
 shaken up with an equal volume of strong alcoholic potash diluted with 6 pts. alcohol, 
 and the whole gently heated : after a time a white curdy precipitate separates, which 
 is boiled with water, and purified by solution in alcohol Benzimide also occurs, 
 mixed with hydride of benzoyl and benzoin, in the resinous residue of the rectification 
 of oil of bitter-almonds : it may be extracted by treating the residue with hot alcohol. 
 Benzimide forms a light loosely-coherent mass, white, with a greenish tinge, and 
 leaves a stain when rubbed or pressed. It is insoluble in water, or in cold potash or 
 hydrochloric acid ; sparingly soluble in boiling alcohol or ether. When heated, it melts, 
 and finally volatilises with decomposition, leaving a carbonaceous residue. It dissolves 
 in strong sulphuric acid with a green colour, which soon changes to red, and is re- 
 precipitated by water. Nitric acid dissolves it with decomposition : heated with nitric 
 acid and alcohol, it evolves red fumes and yields ammonia and benzoate of ethyl. 
 Boiled with hydrochloric acid, it yields hydride of benzoyl, sal-ammoniac, and probably 
 also formic acid. 
 
 C 23 H 18 N 2 2 + 5H 2 = 3C 7 H 6 + 2CH 2 2 + 2NH 3 . 
 
 Heated with strong bases, it yields benzene ; and with pofcassic hydrate moistened with 
 alcohol, it forms ammonia and potassic benzoate. F. T. C. 
 
 BENZINE. Syn. with BENZENE (q. v.) 
 
 BENZOACETIC AXTHYDRXDE. See ACETIC ANHYDRIDE. 
 
 BEN ZO ANGELIC ANHYDRIDE. See BENZOIC ANHYDRIDE. 
 
 BENZOCARBOLIC ACID. BENZOATE OF PHENYL. See BENZOIC ACID. 
 
 BENZOCHLORHYDRIN, C IO HC10 8 (Berth elot, Ann. Ch. Phys. [3] xli. 302). 
 One of Berthelot's artificial fats, containing the elements of benzoic and hydrochloric 
 acids and glycerin, minus water : 
 
 C 7 H 6 O 2 + HC1 + C 3 H 8 3 = C 10 H U C10 S + 2H 2 0. 
 
 It is prepared by saturating with hydrochloric acid gas a mixture of glycerin and 
 benzoic acid, which is kept for several hours at 100 C., and removing the excess of acid 
 by sodic carbonate : the benzochlorhydrin then sinks to the bottom as an oily liquid. 
 .When pure, it is a neutral oil, solidifying at 40. It is decomposed by potash, 
 yielding potassic chloride and benzoate : and by hydrochloric acid and alcohol, yield- 
 ing glycerine and benzoate of ethyl. The chlorine is not withdrawn from the 
 compound even by long digestion at 100 with oxide of silver. F. T. C. 
 
 BENZOCITJNA1VIIC ANHYDRIDE. See BENZOIC ANHYDRIDE. 
 
 BENZOCTJMINIC ANHYDRIDE. See BENZOIC ANHYDRIDE. 
 
 BENZOCUXKYXiSirXiPHOPHEXTAlWIDE;. See BENZAMIDE. 
 
 BENZOEN. Syn. with Toluol. See BENZYL, HYDRIDE OF. 
 
 BENZOERETIC ACID. Amorphous benzoic acid, Parabcnzoic acid (E. Kopp. 
 Compt. chim. 1849, 154). An amorphous powder, obtained by heating gum-benzoin 
 with 6 or 8 pts. nitric acid, not strong enough to form nitrobenzoic acid. When 
 quite pure, it is white ; but it is commonly yellowish, owing to the presence of a small 
 quantity of a yellow resin, which accompanies it into all its compounds. It is readily 
 soluble in alcohol, ether, and boiling water. It has an aromatic, faintly sour and 
 bitter taste. It melts at 113 C., boils at 256, and by dry distillation yields pure crys- 
 
 N N 2 
 
548 BENZOGLYCOLLIC ACID. 
 
 talline benzoic acid, and, if not quite pure, a slight carbonaceous residue. When 
 gently heated, or exposed to the sun, it becomes covered with small crystals of 
 benzoic acid. Distilled with lime, it yields benzene. It forms salts which crystallise 
 with difficulty, and are generally less soluble than the corresponding benzoates. 
 Different specimens have yielded different results to analysis : but in some cases tho 
 composition is very near that of benzoic acid. F T. C. 
 
 BENZOGLYCOLLIC ACID. C 9 H 8 4 = (C 2 H 2 0)".C 7 H 5 O.H.0 2 (Strecker[1847J, 
 Ann. Ch. Pharm. Ixviii. 54. StreckerandSocoloff, ibid. Ixxx. 18. Grossman, ibid. 
 xc. 181; xci. 359). Formed by the action of nitrous anhydride on hippuric acid: 
 
 2C 9 H 9 N0 3 + N 2 S = 2C 9 H 8 4 + N 4 + H 2 0. 
 
 It is prepared by rubbing hippuric acid to a thin paste with strong nitric acid, and 
 passing a current of nitric oxide into the mixture : nitrogen is then evolved, and the 
 hippuric acid gradually dissolved. After some time, the clear solution becomes opaque 
 from the deposition of benzoglycollic acid : the current of gas is kept up until the 
 liquid assumes a greenish colour, when a large quantity of water is added, and the whole 
 allowed to cool. The acid then separates out in considerable quantities ; it is collected 
 on a filter, washed with cold water, suspended in water, neutralised with milk of lime, and 
 the resulting calcium-salt is purified by recrystallisation and pressure between paper, and 
 subsequently decomposed by hydrochloric acid (Socoloff and Strecker). It may also 
 be prepared by slowly passing chlorine into a solution of hippuric acid in excess of 
 moderately dilute potash: when the evolution of nitrogen ceases, the mixture is 
 carefully neutralised by hydrochloric acid, concentrated by gentle evaporation, and 
 mixed with a slight excess of hydrochloric acid, when it solidifies to a crystalline mass. 
 This is purified by solution in ether, and distilling off the ether from the watery layer 
 below it, when the acid separates as an oil in the midst of the water (Grossman). 
 The acid obtained by either of these methods generally contains a large quantity 
 of benzoic acid, which is removed by partially neutralising the acid with milk of 
 lime and evaporating to dryness : benzoic acid, being the weaker acid of the two, 
 remains uncombined, and is extracted from the residue by ether. 
 
 Benzoglycollic acid crystallises from alcohol in colourless prisms of 37 40' and 
 142 20', which often take the form of thin plates : when precipitated by acids from 
 aqueous solutions of its salts, it separates as a white crystalline powder. It is scarcely 
 soluble in cold, more so in hot water, readily in alcohol and ether : it melts in hot 
 water before dissolving. It melts when heated and solidifies to a crystalline mass ; 
 heated more strongly, it gives off vapours containing benzoic acid, and leaves a slight 
 residue of carbon. When boiled for some time with water, it is gradually decomposed 
 into benzoic and glycollic acids : 
 
 C'H 8 4 + H 2 = C 7 HO a + C 2 H 4 0. 
 This decomposition is accelerated by the presence of a mineral acid. 
 
 BENZOGLYCOLLATES are mostly crystalline, soluble in water, some of them in alcohol 
 also. They are neutral to litmus, and have a faint but peculiar taste. Their aqueous 
 solutions may be boiled and even evaporated to dryness without decomposition. From 
 most of their solutions strong acids separate benzoglycollic acid as a crystalline powder. 
 The acid being monobasic, their general formula is C 9 H 7 MO 4 . 
 
 The Ammonium-salt is obtained by saturating the acid with ammonia, or decompos- 
 ing the calcium-salt with ammonic carbonate. It loses ammonia when evaporated. 
 
 The Barium-salt, C 9 H 7 Ba0 4 + Aq, forms delicate silky needles, which lose their 
 water at 100 C. 
 
 The Calcium-salt, C 9 H 7 Ca0 4 + Aq, forms delicate silky needles, united in groups, 
 which lose their water at 120 C. It dissolves in 42-3 pts. cold, and 7'54 pts. boiling 
 water. It possesses in a remarkable degree the property of forming supersaturated 
 solutions, so that a solution saturated at boiling heat frequently takes some days to 
 deposit all its crystals in successive crops. When a strong solution of this salt is eva- 
 porated with chloride of calcium to a syrupy consistence, a double salt separates out 
 on cooling in octahedrons, which are permanent in the air, but are decomposed by 
 water or alcohol into benzoglycollate and chloride of calcium. 
 
 The Copper-salt crystallises on cooling in abundant blue rhombic tables, when a 
 boiling saturated solution of the calcium-salt is mixed with nitrate of copper. It 
 becomes green and opaque at 1 00 C, but retains its lustre ; is scarcely soluble in cold, 
 more so in hot, water. 
 
 The Ferric salt, 2Fe<0 3 .3C 18 H0 7 + 28Aq, or 3(/e0.2C 9 H 7 /e0 4 ) + Aq, is a volu- 
 minous flesh-coloured precipitate, insoluble in water, which becomes darker when 
 dried. After drying in the air, it loses 27'36 per cent. (28 at.) water at 100 C. 
 
 There appear to be at least two basic Lead-salts besides the normal one. When a 
 cold solution of benzoglycollate of calcium is mixed with normal acetate of lead, a 
 
BENZOHELICIN BENZOIC ACID. 549 
 
 fiocculenl precipitate is formed, which is a mixture of several salts. If this be 
 dissolved in cold water, the solution, on spontaneous evaporation, yields, first, crystals 
 of the salt b, and subsequently soft starry crystals of the normal salt CFIFPbO 4 , which 
 melt with partial decomposition at 100 C. 
 
 b. 4C 9 IFPb0 4 .Pb 2 O + 3Aq, forms hemispherical groups of crystals, which melt at 
 100, and lose 1| at, water. 
 
 c. 2C''IFPb0 4 .5Pb 2 + 2Aq. When the cold solution of the calcium-salt is mixed 
 with basic acetate of lead, and the precipitate digested in cold water and filtered, this 
 salt crystallises after some days. It loses 1 at. water at 100 C. 
 
 The precipitate obtained by adding the calcium-salt to a boiling solution of normal 
 acetate of lead, is a mixture of several basic salts. 
 
 The Magnesium salt forms long, very slender needles, readily soluble in water and 
 alcohol. 
 
 The Potassium- and Sodium-salts are obtained like the ammonium-salt. The former 
 crystallises with difficulty, being very soluble. The latter crystallizes more readily 
 from a hot saturated solution in rhombic tables ; it contains 3Aq, which it loses at 
 100 C. 
 
 The Silver-salt, C 9 H 7 Ag0 4 , is obtained as a curdy precipitate when the neutral 
 ammonium salt is mixed with nitrate of silver ; this precipitate is washed in cold, and 
 dissolved in boiling, water, whence it separates in white microscopic crystals, which 
 when moist quickly blacken in the light; when dry they are not changed at 100 C. 
 
 Zinc-salt, C 9 H 7 ZnO* + 2Aq. A boiling saturated solution of the calcium-salt 
 mixed with chloride of zinc, yields on cooling long thin needles, which are dried by 
 filter paper and recrystallised. They lose 2 at. water at 100 C. F. T. C. 
 
 BENZOHELICIN. C 20 H 20 8 . (Piria, Ann. Ch. Phys. [3] xxxiv. 278; xliv. 366.) 
 The product of the action of the nitric acid on populin. It may be regarded as 
 helicin, <C 13 H 17 7 ), in which 1 H is replaced by benzoyl, C 20 H 20 8 = C 13 H 15 (C 7 H 5 0)0 T . 
 It is to populin (benzosalicin) as helicin is to salicin. 
 
 Obtained by dissolving populin in pure nitric acid of specific gravity 1'3, the solu- 
 tion becomes yellow, and benzohelicin soon crystallises out. On diluting the mother- 
 liquor with water, more crystals separate out. It forms silky needles closely resem- 
 bling helicin. When boiled with water and magnesia, it is converted into helicin and 
 benzoic acid. Synaptase has no action upon it. Acids and alkalis convert it into benzoic 
 acid, hydride of salicyl, and glucose : 
 
 C 20 H 20 8 + 2H 2 = C 7 H 6 3 + C 7 H 6 2 + C"H 12 6 . 
 
 Hydride Glucose, 
 
 salicyl. 
 
 F. T. C. 
 
 BENZOIC ACID. Flowers of Benzoin. Hydrate of BenzoyL Benzoeblumen. 
 Benzoesaure. Acide benzo'ique. C 7 H 6 2 = C 7 H 5 O.H.O. [or VWO* = C"H*O.HO.] 
 
 History and Sources First noticed by Blaise de Vigenere (Traite du feu ct du 
 sel, 1608). Its true composition was determined by Liebig and Wohler (Ann. 
 Ch. Pharm. iii. 249). It occurs ready formed in gum -benzoin, dragon's blood, 
 storax, Peru and Tolu balsams, and in many other resins and balsams ; also in casto- 
 reum (Wohler, Ann. Ch. Pharm. Ixvii. 360), in the spindle tree, Euonymus europoeus, 
 (Schweizer, J. pr. Chern. 411, 437), and in the putrefied urine of man and of grami- 
 nivorous animals (Liebig, ibid. 1. 168). 
 
 Formation. It is formed in a great number of organic reactions. 1. By the oxida- 
 tion of hydride of benzoyl, even by its exposure to moist air. 2. By the action of 
 water on chloride, bromide, or iodide of benzoyl. 3. By heating benzylic alcohol with 
 aqueous chromic acid. 4. By the action of nitric acid on hydride of cinnamyl, cinna- 
 mic acid, cinnamol, cumol, and cuminol. 5. By oxidising casein or gelatin with sul- 
 phuric acid and binoxide of manganese (Griickelberger, Ann. Ch. Pharm. Ixiv. 80). 
 6. From hippuric acid, by putrefaction, or by boiling with acids or alkalis. 7. By the 
 action of dilute alkalis on populin. 8. By the dry distillation of insolinic (Hofmann) 
 and quinic acids (Wohler, Ann. Ch. Pharm. li. 145). 
 
 Preparation. Gum-benzoin is employed for the preparation of benzoic acid on the 
 large scale; the process may be conducted either in the dry or wet way. The best 
 method of preparing it in the dry way, or by sublimation, is that given by Mohr, 
 Ann. Ch. Pharm. xxix. 177). The coarsely-powdered resin is placed at the bottom of 
 a round shallow iron-pot, 8 inches in diameter and 2 inches deep ; the mouth is closed 
 by a diaphragm of coarse filter-paper, closely cemented to the sides of the vessel ; and 
 over this is tied a covering of thick paper, in size and shape like a hat. The vessel 
 is then heated gently and slowly on a sand-bath (1 Ib. of gum requires 3 or 4 hours), 
 On removing the paper-cover when the whole is cool, it is found lined with a crystalline 
 sublimate of benzoic acid. The diaphragm allows the vapours of benzoic acid to pass 
 
 N N 3 
 
550 BENZOIC ACID. 
 
 through it, purifies them in great measure from empyreumatic products, and prevent* 
 the sublimed acid from falling back into the vessel. About 4 per cent, acid is thus 
 obtained : if the residue in the iron vessel be broken up and again heated, the yield 
 may be increased to 12| per cent. The acid prepared by this method, which is on the 
 whole the best for pharmaceutical purposes, is quite pure, with the exception of traces 
 of a volatile oil, which gives it a smell like that of vanilla, and on which its medical 
 properties depend, at least to some extent. The extraction of the acid from gum- 
 benzoin may be effected more completely in the wet way. Sch eel e's process (Opusc. 
 ii. 23) is to mix 2 pts. resin with rather less than 1 pt. quick lime, which is first 
 slaked, to digest the mixture for some hours with 20 pts. cold water, and to boil the 
 whole for half an hour. The solution containing benzoate of calcium is filtered 
 from the residue, which is then washed with hot water, evaporated to one-half, and 
 mixed with excess of hydrochloric acid ; the benzoic acid which crystallises out on cooling 
 is pxirified by recrystallisation from hot water, or by sublimation. If sodic carbonate be 
 employed instead "of lime, a portion of the resin is apt to be dissolved, which colours the 
 benzoic acid, and cannot be removed without difficulty. Wohler (Ann. Ch. Pharm. 
 xlix. 245) gives the following method: Powdered gum-benzoin is dissolved by the 
 aid of heat in an equal volume of alcohol of 90 95 per cent., the hot solution mixed 
 with fuming hydrochloric acid till the residue begins to be precipitated, and the whole 
 distilled as long as its consistency permits ; it is then aDowed to cool, and again dis- 
 tilled with water as long as any benzoic ether passes over. The joint distillates, con- 
 taining benzoic ether, alcohol, and hydrochloric acid, are heated with caustic potash 
 until the ether is entirely decomposed, and the resulting solution of potassic benzoate 
 decomposed by hydrochloric acid. The acid thus obtained precisely resembles that 
 prepared by Mohr's method. 
 
 Benzoic acid may also be prepared from hipptiric acid by boiling it for half an hour 
 with strong hydrochloric acid, and washing the product with cold water. Benzoic 
 acid is sometimes met with in commerce, which is prepared from the urine of grami- 
 nivorous animals. The urine is allowed to putrefy, then mixed with milk of lime and 
 filtered ; and the filtrate is evaporated and precipitated by hydrochloric acid. If the 
 resulting benzoic acid be coloured, it is redissolved in thin milk of lime, the whole boiled 
 with chloride of calcium, hydrochloric acid added, and the precipitate recrystallised from 
 boiling water. The acid thus prepared is inferior to and cheaper than that obtained 
 by sublimation. It always smells of urine, and never has the peculiar smell of the 
 sublimed acid. 
 
 Properties. Benzoic acid crystallises in colourless, transparent, pearly needles or 
 laminae, which, under the magnifying glass, appear to be six-sided prisms. It has no 
 smell, and a faint but persistent sour and warm taste. It reddens litmus. It melts 
 at 121-4 C. to a colourless liquid of specific gravity 1*0838 (water at being taken as 
 unity), and boils without decomposition at 249'2 (at 740 mm. pressure) (Kopp). It 
 begins to sublime at a much lower temperature, and distils over abundantly with 
 vapour of water. Its vapour-density is 4'27 (Mitscherlieh); the vapours excite 
 coughing. It dissolves in 200 pts. cold, and in 24 30< pts. boiling water, much more 
 readily in alcohol and ether. Fats and volatile oils dissolve it abundantly. It dissolves 
 in strong sulphuric acid without decomposition, and is reprecipitated by water. It is 
 not attacked by boiling dilute nitric or chromic acid ; and is thus distinguished from 
 cinnamic acid, which, under these circumstances, yields hydride of benzoyl. 
 
 Decompositions. 1. By heat. When vapour of benzoic acid is passed through a 
 red-hot tube filled with fragments of pumice-stone, it is decomposed into benzene and 
 carbonic anhydride. The same decomposition takes place at a lower temperature when 
 1 pt. acid is heated in a retort with 5 or 6 pts. coarsely powdered pumice. If too 
 much heat be applied, naphthalin and some empyreumatic products are also formed, 
 and a residue of carbon left (Barreswil and Boudault). If benzoic acid be heated 
 with lime, only benzene passes over, the carbonic anhydride being retained by the lime. 
 Heated in contact with air, benzoic acid burns with a bright smoky flame, and leaves 
 no residue. 2. Dry chlorine acts upon benzoic acid in sunlight, forming a reddish, 
 tough, gnromy mass, whence potassic carbonate extracts chlorobenzoic acid (see below), 
 and leaves a brown-red residue, which smells of benzoin, and contains chlorine 
 (Herzog). Bromine acts on benzoic acid in similar a manner. When chlorine 
 is passed into a hot aqueous solution of benzoic acid, or when benzoic acid is boiled 
 with aqueous chloride of lime, or with potassic chlorate and hydrochlo.ric acid, a mix- 
 ture of mono-, di-, and tri-chlorobenzoic acids is obtained ; but these acids have not been 
 separated and examined (Stenhouse, Ann. Ch. Pharm. Iv. 10). When a solution of 
 benzoic acid in excess of potash is saturated with chlorine, chloroniceic acid, C^IPCIO 2 , 
 is produced (St. Evre). 3. When benzoic acid is heated with strong nitric acid, 
 'nitrobenzene acid is formed: a mixture of sulphuric and fuming nitric acid converts it 
 into dinitrobcnzoic acid. 4. Fuming sulphuric acid converts it into sulphobenzoic 
 
BENZOIC ACID. 551 
 
 ftcid. 5. Heated to 200 C. with a mixture of anhydrous acid sulphate of sodium, 
 (Na 2 S0 4 .S0 3 ) and chloride of sodium, it yields chloride of benzoyl together with hydro- 
 chloric acid. 
 
 C 7 H 6 2 + SO 8 + 2NaCl = C 7 H 5 OC1 + IIC1 + Na 2 S0 4 . 
 
 The neutral sulphate of sodium is associated with the sulphuric anhydride to prevent 
 the latter from converting the benzoic acid into sulphobenzoic acid (Beketoff, 
 Ann. Ch. Pharm. cix. 256). 6. Perchloride of phosphorus does not act upon benzoic 
 acid till heat is applied, when hydrochloric acid is evolved, and chlorides of benzoyl 
 and of phosphoryl formed. 7. In the animal organism, benzoic acid is converted into 
 hippuric acid, which is found in the urine. (Wohler, &c.) 
 
 BENZOATES. Benzoic acid decomposes carbonates, but an alcoholic solution of 
 potassic benzoate is decomposed by carbonic anhydride, potassic carbonate being pre- 
 cipitated. It is a monobasic acid, but forms some acid and basic salts. The normal 
 benzoates are mostly crystallisable, and soluble in water and alcohol. Their aqueous 
 solutions are decomposed by almost all acids, benzoic acid being precipitated. Alkaline 
 and alkaline-earthy benzoates yield, by dry distillation, benzene, benzone, solid hydro- 
 carbons isomoric with naphthalin, and a metallic carbonate. A mixture of benzoate 
 and formate of potassium yields, when heated, hydride of benzoyl (Piria). "With 
 chloride of phosphoryl, alkaline benzoates yield chloride of benzoyl and a phosphate ; 
 with chloride of benzoyl, an alkaline chloride and benzoic anhydride. With 
 perchloride of phosphorus or chloride of sulphur, they yield either chloride of benzoyl 
 or benzoic anhydride, according to the proportion of benzoate present. 
 
 Benzoate of Ammonium, a. Normal. Obtained in crystals by cooling a solu- 
 tion of benzoic acid in strong warm ammonia ; or by evaporating a more dilute solution 
 with addition of ammonia from time to time. It deliquesces in the air, and is soluble 
 in water and alcohol, but less so in the latter than the potassic salt. When heated 
 in a retort, it loses water, and is converted into benzo-nitrile. Its solution loses 
 ammonia on evaporation, yielding : 
 
 b. Acid salt. Obtained in large irregular crystals by the spontaneous evaporation of 
 the solution of . Less soluble than a in water and alcohol. 
 
 Benzoate of Barium, C 7 H 5 Ba0 2 + Aq. Slender permanent needles (Tromms- 
 dorf), or large tables, which become opaque at 100 C. (Plantamour), andlose their 
 water at 110 (Limpricht). 
 
 Benzoate of Cadmium, C 7 H 5 Cd0 2 + Aq. By evaporating a solution of carbonate 
 of cadmium in aqueous benzoic acid, shining aggregated needles are obtained, soluble 
 in hot water, sparingly in alcohol. (Schif f .) 
 
 Benzoate of Calcium, C 7 H 5 Ca0 2 + Aq. Crystallises in feathery needles or in 
 granules, soluble in 29 pts. cold, and in less hot water. 
 
 Benzoate of Copper. A hot solution of sulphate of copper gives with potassic 
 benzoate an aggregate of bluish -green needles (Ettling), which are anhydrous 
 (Mitscherlich). It dissolves in warm dilute acetic acid, and crystallises thence in 
 small green needles. It is insoluble in alcohol. By dry distillation it yields benzene, 
 benzoic acid, benzoate of phenyl, and an oil which boils at 260 C., and, when heated 
 with sulphuric acid, is decomposed into hydrate of phenyl and a solid hydrocarbon, 
 C 5 H 4 : the residue contains salicylate of copper. 
 
 Ferric Benzoate. The normal salt crystallises in yellow needles from a solution 
 of ferric hydrate in aqueous benzoic acid ; it is soluble with decomposition in water 
 and alcohol, a basic salt being left behind. A still more basic salt is obtained when 
 a solution of ferric chloride, containing enough ammonia to give it a dark-red colour, 
 is mixed with an alkaline benzoate : it is a flesh-coloured precipitate, insoluble in, 
 and not decomposed by, cold water, and containing 17'5 per cent. iron. (Berzelius.) 
 Ferrous Benzoate crystallises in needles, which effloresce and turn yellow when 
 exposed to the air, and are soluble in water and alcohol. Benzoate of ammonium does 
 not precipitate ferrous salts. 
 
 Benzoate of Lead. C 7 H 5 Pb0 2 + | Aq. A light crystalline powder, obtained by 
 precipitating normal lead-salts with potassic benzoate. It melts a little above 100 C., 
 and gives off its water (Beo-zelius). When digested with basic acetate of lead, it 
 gradually becomes heavy and granular, being converted into a compound of basic 
 benzoate and acetate of lead (Varrentrapp). A basic salt, C 7 H 5 Pb0 2 'Pb 2 0, is 
 obtained by digesting the normal salt with ammonia, or precipitating benzoate of 
 ammonium with sub-acetate of lead. 
 
 Benzoate of Magnesium. Feathery efflorescent crystals, readily soluble in 
 water. 
 
 Manganous Benzoate. C 7 H 5 Mn0 2 + | Aq. Transparent, colourless, permanent 
 
 N N 4 
 
552 BENZOIC ACID. 
 
 needles, soluble in 20 pts. cold, and in a much smaller quantity of boiling water } 
 sparingly soluble in alcohol. 
 
 Mercuric Benzoate. C 7 H 5 Hg0 2 + | Aq. A white precipitate, made up of 
 slender needles, obtained by adding an alkaline benzoate to a solution of corrosive 
 sublimate. It is insoluble in cold, tolerably soluble in hot, water ; alcohol and ether 
 decompose it, leaving a basic salt, which may also be obtained by boiling benzoic acid 
 with water and excess of mercuric oxide. When treated with ammonia, mercuric 
 benzoate is converted into ammonio-mercuric benzoate, a white powder, insoluble in 
 water, almost insoluble in alcohol or ether ; potash turns it yellow, and eliminates 
 ammonia : it contains 69'92 per cent, mercuric oxide. (Harff.) 
 
 Mercurous Benzoate. C 7 H 5 Hg 2 2 . A bulky crystalline precipitate, consisting 
 of slender needles ; insoluble in cold water ; decomposed by boiling water or alcohol, 
 with separation of metallic mercury. Becomes light-yellow when exposed to the 
 light. Treated with ammonia, it is converted into a black powder, containing 80*9 
 per cent, mercurous oxide. 
 
 Benzoate of Potassium, a. Normal. C 7 H 5 K0 2 + Aq. Crystallises with diffi- 
 culty from an aqueous solution, more easily from hot alcohol, in feathery needles or 
 pearly laminae. It is very soluble in water, has a sharp burning taste, and at 100 C. 
 loses its water. Heated with arsenious hydride, it yields benzene. (Darcet.) 
 
 b. Add salt. C 7 H 5 K0 2 + C 7 H 6 2 . Formed in the preparation of acetic anhydride 
 from chloride of benzoyl and acetate of potassium ; the residue is washed with water, 
 dried, and dissolved in boiling alcohol, when the acid benzoate crystallises in pearly 
 laminae. It is slightly soluble in cold water, or in boiling alcohol. (Gregory.) 
 
 Benzoate of Silver. A white curdy precipitate, obtained by double decomposition : 
 it dissolves in a large quantity of boiling water, and crystallises thence in long shining 
 laminae. When heated, it melts and swells up, and leaves very white metallic silver. 
 It dissolves in 1'96 pts. alcohol, at 100 C. (Mitscherlich.) 
 
 Benzoate of Sodium. Efflorescent pointed crystals, soluble in water, sparingly 
 in alcohol. 
 
 The cobalt-, nickel-, and zinc-salts are crystallisable and soluble in water and alcohol : 
 the aluminium-salt, crystalline, tolerably soluble in water : the lithium-salt, uncrys- 
 tallisable, very soluble : the bismuth-, cerium-, tin-, yttrium-, and zirconium-salts, are 
 white precipitates, sparingly soluble in water. 
 
 BENZOIC ETHEBS. Benzoate of Methyl. Benzoeformester. C 8 H 8 2 = C 7 H 5 (CH 3 )0 2 . 
 (Dumas and Peligot [1835] ; Ann. Ch. Phys. [2] Iviii. 50; Malaguti, ibid. [2] 
 Ixx. 387.) Formed, according to Scharling, in the dry distillation of tolu-balsam. 
 For its preparation, 2 pts. benzoic acid, 1 pt. wood-spirit, and 2 pts. strong sulphuric 
 acid, are distilled together, the residue redistilled two or three times with fresh wood- 
 spirit, and the united distillates mixed with water. The impure benzoate of methyl 
 which is thus precipitated, is washed, dried over chloride of calcium, and rectified 
 over oxide of lead, that portion which comes over above 198 C. being collected apart. 
 It may also be prepared by distilling sulphate of methyl with potassic benzoate. It 
 is a colourless, oily liquid, with a pleasant balsamic smell, insoluble in water, soluble 
 in alcohol and ether : boils at 198'5 C. at 761 mm., or at 199-2 at 746 mm. (Kopp). 
 Specific gravity 1-10 at 17, or 1-0876 at 16'3 (Kopp): vapour-density, by experi- 
 ment, 4717. Its vapour, passed through a red-hot tube filled with lime, yields, among 
 other products, benzene. It absorbs chlorine without apparent alteration : when the 
 saturated liquid is heated, hydrochloric acid and chloride of methyl pass over first, 
 and then chloride of benzoyl in abundance ; the coloured residue contains benzoic acid r 
 benzoate, and (probably) chlorobenzoate of methyl. 
 
 Benzoate of Ethyl. Benzoevinester. C 9 H 10 2 - C 7 H 5 (C 2 H 5 )0 2 . (Scheele, Opusc. 
 ii. 141 ; Dumas and Boullay, Ann. Ch. Phys. [2] xxxviii. 20; WohlerandLiebig, 
 Ann. Ch. Pharm. iii. 274 ; Deville, Ann. Ch. Phys. [3] iii. 188.) Benzoate of ethyl 
 is not formed by the mere contact of benzoic acid and alcohol, however prolonged ; but 
 the reaction takes place gradually when the mixture is heated to 100 C. in a sealed tube, 
 or when a small quantity of a strong acid is added to it. The statements of Deville and 
 Cahours, that it is formed by the dry distillation of tolu-balsam and gum-benzoin, seem 
 to require confirmation. It is prepared by distilling 4 pts. alcohol with 2 pts. benzoic 
 acid, and 1 pt. fuming hydrochloric acid, till two-thirds have passed over, and pouring 
 back the distillate into the retort two or three times : a little of the ether passes over, 
 but the greater part remains in the residue, whence it is separated by addition of 
 water. Or a solution of 3 pts. benzoic acid in 2 pts. boiling alcohol of 80 per cent, is 
 heated for some time. Liebig and Wohler prepare it by dissolving chloride of benzoyl 
 in absolute alcohol : heat and hydrochloric acid are evolved, and the addition of water 
 separates the ether. The ether prepared by any of these methods, contains some free 
 
EENZOIC ACID. 553 
 
 benzole acid, from which it is purified by agitation with sodic carbonate, washing with 
 water, and rectification over oxide of lead. 
 
 Benzoate of ethyl is a colourless oil, with a pleasant aromatic smell, and a pungent 
 taste ; boils at 212-9 C., when the barometer stands at 745*5 mm. Specific gravity 
 1-0556 at 10-5 C. (Kopp). Vapour-density by experiment, 5'406. It is slightly 
 soluble in water, soluble in all proportions in alcohol and ether. It burns with a bright 
 smoky flame. Chlorine does not act upon it below 60 or 70 C., when hydrochloric 
 acid and chloride of ethyl pass over : on heating the mixture, a colourless distillate 
 passes over at 190, to which Malaguti (Ann. Ch. Phys. [2] Ixx. 374), assigns the 
 formula C 18 H 16 C1 6 3 , regarding it as a compound of chloride of benzoyl with bichloro- 
 vinic ether : the black residue, when further heated, yields chloride of benzoyl. Nitric 
 acid, or a mixture of nitric and sulphuric acids, converts it into nitrobenzoate of ethyl. 
 It is not attacked by perchloride of phosphorus (Cahours). When distilled over fused 
 chloride of zinc, it yields chloride of ethyl and benzoate of zinc, which latter is de- 
 composed by further heat, forming benzoic acid and benzene. Ammonia acts upon it 
 slowly, at the ordinary temperature ; but, if the mixture be heated above 100 C. in a 
 sealed tube, benzamide is readily formed. Aqueous potash converts it very slowly into 
 alcohol and potassic benzoate: when heated with solid potash or potash-lime, hy- 
 drogen is evolved, and benzoate and acetate of potassium formed (Dumas and Stas). 
 Sodium acts upon it between 60 and 70 C. : the liquid turns brown, without evo- 
 lution of gas, yielding, among other products, the ether of a peculiar acid. (See HYPO- 
 
 BENZOYLOUS AdD.) 
 
 Benzoate of Ethylene. Benzoate of Glycol. C 16 H0* = (C 7 H 5 0) 2 .(C 2 H*)".0 2 . 
 (M. Simpson and Wurtz, Ann. Ch. Phys. [3] Iv. 400.) Obtained by the action of 
 dibromid of ethylene on benzoate of silver. It is soluble in ether, and crystallises 
 from the solution in colourless, shining, right-rhombic prisms. Melts at 67 C., and 
 distils without alteration at a temperature above the boiling point of mercury. 
 
 Benzoate of Amyl C 12 H 16 O 2 = C 7 H 5 (C 5 H)0 2 (Kieckher, (1847), Jahr. pr. 
 Pharm. xiv. 15). Obtained by distilling 1 pt. fusel-oil and 2 pts. sulphuric acid with 
 excess of alkaline benzoate. It is a yellowish oil of peculiar smell : boils at 260 '7 C. 
 when the barometer stands at 745 P 6 mm. Specific gravity 0-9925 at 14-4 (Kopp) : 
 readily decomposed by alcoholic potash. 
 
 Benzoate of Allyl. Bcnzoepropylenyl C 10 H 10 2 = C 7 H 5 (C 3 H 5 )0 2 (Zinin, Ann. Ch. 
 Pharm. xcvi. 362; Cahours and Hofmann, ibid. cii. 297; Berthelot and De 
 Luca, Ann. Ch. Phys. [3] xlviii. 286). Obtained by distilling equal quantities of 
 iodide of allyl and benzoate of silver, washing the distillate with sodic carbonate, and 
 rectifying over oxide of lead. Also by the action of chloride of benzoyl on allylic 
 alcohol. A yellow aromatic oil, heavier than water : boils at 230 240 C. : insoluble 
 in water, soluble in alcohol or ether: decomposed by boiling with potash. 
 
 Benzoate of Benzyl Benzoate of Tolyl. (Canizzaro.) C 14 H 12 8 = C 7 H 5 (C 7 H 7 )0 2 . 
 When chloride of benzoyl and benzylic alcohol are distilled together in equal propor- 
 tions, hydrochloric acid is evolved, benzoic acid and chloride of benzyl pass over, and 
 finally benzoate of benzyl, in the form of a yellowish oil, which crystallises on cooling. 
 It is purified by pressure between filter-paper, rectification over benzoic anhydride, 
 washing with sodic carbonate, and another rectification. It forms colourless crystal- 
 line laminae, which melt below 20 C., and boil at about 345. After fusion, it recrys- 
 tallises with great difficulty, often requiring the aid of a freezing mixture. It is isomeric 
 with benzoin. 
 
 Benzoate of Glycyl. See BENZOICIN. 
 
 Benzoate of Phenyl. Benzophenid. Benzoeoxyd. Benzocarbolic acid. C 13 H I0 2 = 
 C 7 H 5 (C 6 H 5 )O 2 . (Ettling (1845), Ann. Ch. Pharm. liii. 87; Stenhouse, ibid.im. 
 91 ; Laurent and Gerhardt, ibid. Ixxv. 75; List and Limpricht, ibid. xc. 190.) 
 Obtained by the action of chloride of benzoyl on phenylic alcohol or phenylate of 
 potassium : by the dry distillation of benzoate of copper (Ettling) : by heating ben- 
 zosalicylic anhydride (Gerhardt). List and Limpricht have shown the identity of 
 the substances obtained by all these methods. It is best prepared by heating phenylic 
 alcohol with chloride of benzoyl, as long as hydrochloric acid is evolved, washing the 
 crystalline product with potash, exhausting it with ether-alcohol, and evaporating the 
 solution to crystallisation. To obtain it from benzoate of copper, the dry salt is dis- 
 tilled over the open fire as long as vapours are evolved ; the distillate again distilled 
 with excess of sodic carbonate, as long as benzene passes over with aqueous vapour ; the 
 insoluble residue in the retort separated from the alkaline liquid, washed with water, 
 and dissolved in hot alcohol ; and the crystals which separate on cooling, purified by 
 repeated crystallisation from hot alcohol. (List and Limpricht.) 
 
 Beuzoate of phenyl forms hard, shining, colourless, rhombic prisms, often half an 
 
554 BKNZOIO ACID. 
 
 inch long. It melts at 66 C., and cools to a crystalline mass : at a higher temperature 
 it volatilises undecomjposed. It has a faint smell of geraniums, or, when heated, of 
 lemons : is insoluble in water, soluble in alcohol and ether, especially on heating. It 
 burns with a red, very smoky flame. Chlorine and bromine convert it into substitution- 
 products (see below^j. Sulphuric acid dissolves it readily; the addition of water 
 separates benzoic acid, while sulphophenylic acid remains in solution. Boiling hydro- 
 chloric acid does not attack it. It is not decomposed by boiling with aqueous potash, 
 but, if the mixture be heated to 150 170 C. in a sealed tube, potassic benzoate and 
 phenylate are formed : the same decomposition is effected by fusion with solid potash, 
 or by contact with alcoholic potash, even in the cold. It may be boiled with alcoholic 
 ammonia without decomposition ; if the mixture be heated to 150 C. in a sealed tube, 
 phenylic alcohol and benzamide are formed, but no aniline. It is similarly decom- 
 posed when distilled in a stream of dry ammonia. Perchloride of phosphorus does not 
 attack it. (List and Limpricht.) 
 
 Substitution-products of Benzoate of Phenyl. 
 
 1, 2, or 3 at, H in benzoate of phenyl may be replaced by Br, Cl, or NO 2 . These 
 substitution-products are obtained either by the direct action of chlorine, bromine, or 
 nitrosulphuric acid, on benzoate of phenyl ; or by the action of chloride of benzoyl on 
 the substitution-products of hydrate of phenyl. 
 
 Benzoate of Bromophenyl, C 13 H 9 BrO' = C 7 H 5 (C 6 H 4 Br)0 2 , and of Dibromo- 
 phenyl, C 13 H 8 Br 2 2 = C 7 H 5 (C fi H 3 Br 2 )0 2 . Bromo- and Dibromo-benzophenid. (List 
 and Limpricht, loc. tit.} When dry benzoate of phenyl is treated with bromine as long 
 as any hydrobromic acid is eA-olved, the excess of bromine distilled off, and the residue 
 repeatedly crystallised from hot alcohol, large colourless needles are obtained, which 
 melt below 100 C., sublime undecomposed, and are insoluble in water, but soluble in 
 hot alcohol and ether. From the great variation in the analyses, this compound is 
 certainly a mixture of at least two substitution-compounds : and it is probable that 
 tribromobenzophenide is present also. The substance is dissolved and decomposed by 
 cold alcoholic potash, into benzoic, bromophenylic, and dibromophenylic acids. 
 
 Benzoate of Chlorophenyl. Chlorobenzophcnid. C 13 H 9 C10 2 = C 7 H 5 (C 6 H 4 C1)0 2 . 
 (Stenhouse, loc. tit.} When dry chlorine is led for some days over fused benzoate 
 of phenyl, a dark-yellow mixture is produced, consisting of an oily and a solid body, 
 having a very pungent smell : this is pressed between filter-paper, and the solid resi- 
 due repeatedly crystallised from ether. Large flat crystals are thus obtained, which 
 melt at 84 C., and sublime in four-sided prisms : they have a faint smell, like that of 
 sesquichloride of carbon. From analyses, this substance appears to be a mixture of 
 chloro- with dichloro-benzophenide. The oily substance contains more chlorine, and 
 probably consists in part of trichlorobenzophenide. Both compounds, when heated with 
 alcoholic potash, yield chloride and benzoate of potassium, and on addition of hydro- 
 chloric acid, a dark, resinous body, smelling of creosote, which is probably impure 
 chlorophenylic acid. 
 
 Benzoate of Dinitrophcnyl. Dinitrobcnzophenide. C 13 H 8 N 2 6 = C 7 H 5 (C 6 H S 
 (N0 2 ) 2 )0 2 . (Laurent and Gerhardt, loc. tit.} Dinitrophenylic acid is heated with 
 chloride of benzoyl, as long as hydrochloric acid is evolved ; and the product is extracted 
 with dilute ammonia, washed with cold alcohol, and crystallised from boiling alcohol. 
 Yellow rhombic laminae, insoluble in water, slightly soluble in hot alcohol, more 
 readily in warm ether, partly soluble in potash. 
 
 Benzoate of Trinitrophenyl. Trinitrobenzophenide. C 13 H 7 N 3 8 = C 7 H 5 (C 8 H 2 
 (N0 2 ) 3 )0 2 . Prepared like the preceding compound, trinitrophenylic (picric) acid being 
 substituted for dinitrophenylic acid. Shining yellow rhombic laminae, less soluble in all 
 menstrua than the dinitro-compound. When heated, it melts and solidifies to a 
 crystalline mass : heated more strongly, it explodes. Dissolves in boiling potash, form- 
 ing a dark-red solution, whence acids precipitate crystalline flakes. 
 
 Substitution-products of Benzoic Acid. 
 
 BROMOBENZOIC Aero. C 7 H 5 Br0 2 . (Peligot [1836], Ann. Ch. Pharm. xxviii. 246 ; 
 Herzog, N. Br. Arch, xxiii. 16; Miiller, Compt. rend. xxx. 325.) Benzoic acid is 
 treated with bromine in the sunshine, the excess of bromine distilled off, the residue 
 dissolved in sodic carbonate (when an oil containing bromine remains undissolved), 
 and the solution precipitated by nitric acid (Herzog). Peligot makes bromine- 
 vapour act upon benzoate of silver, by placing the salt, together with a tube contain- 
 ing bromine, in a closed vessel, and leaving it for twenty-four hours : from the product 
 the bromobenzoic ncid is dissolved out by ether. The solution, on evaporation, yields 
 a brown oil, which crystallises on cooling: this is dissolved in potash, treated with 
 animal charcoal, and reprocipitated by nitric acid. It forms a colourless crystalline 
 
BENZOIC ACID. 555 
 
 mass, which melts at 100 C., and sublimes at 250, leaving a residue of carbon. It 
 burns with a smoky green-edged flame : is sparingly soluble in water, readily in alcohol 
 and ether. 
 
 Bromobenzoates are generally soluble and crystallisable : the lead-, copper-, and 
 .mercurous-salts are less soluble. The silver-salt, C 7 H 4 AgBr0 2 , is soluble in warm 
 water. 
 
 CHLOROBENZOIC Aero. Chloromichmylic acid. C 7 H 5 C10 2 . (Herzog, 1840, N. Br. 
 Arch, xxiii. 15 ; Scharling, Ann. Ch. Pharm. xli. 49 ; xlii. 268 ; Sten h ouse, ibid. Iv. 1; 
 Field, ibid. Ixv. 55; Limpricht and v. Uslar, ibid. cii. 259; Chiozza, Ann. Ch. 
 Phys. [3] xxxvi. 102). When dry benzoic acid is acted on by chlorine, a moist viscid 
 reddish mass is formed, which appears to contain a mixture of mono-, bi-, and tri- 
 chlorobenzoic acids ; these acids (which Stenhouse also obtained by treating benzoic 
 acid with chloride of lime and hydrochloric acid), cannot be separated from each other. 
 Limpricht and Uslar obtained pure chlorobenzoic acid from chloride of chlorobenzoyl. 
 According to them, the acid obtained by Chiozza, by the action of perchloride of 
 phosphorus on salicylic acid, is not identical, but isomeric, with chlorobenzoic acid : 
 we shall describe it separately as parachlorobenzoic acid. There is no doubt that the 
 chloromichmylic acid obtained by Scharling by distilling urine with nitric acid, is 
 identical with chlorobenzoic acid. 
 
 Limpricht and Uslar boil chloride of chlorobenzoyl (obtained by the action of per- 
 chloride of phosphorus on chlorosulphobenzoic acid) with potash, and saturate the 
 solution with hydrochloric acid : the precipitated chlorobenzoic acid is purified by re- 
 combination with a base and reprecipitation by an acid. It forms colourless, concen- 
 trically-grouped prisms, which melt at about 140 C., but sublime at a lower tempe- 
 rature in small needles. It dissolves sparingly in cold water, readily in hot water, 
 alcohol, or ether. Fuming nitric acid converts it into nitrochlorobenzoic acid. The 
 chlorobenzoatcs are generally soluble. The solution of the ammonium-salt gives off 
 ammonia abundantly when evaporated, so that the residue is nearly pure chlorobenzoic 
 acid. The acid which Field obtained by boiling benzoic acid with potassic chlorate and 
 hydrochloric acid, melts with difficulty, and blackens when heated. The barium- and 
 calcium-salts crystallise with 1| aq., which they lose at 100 C. The lead-salt is a white 
 precipitate, which melts and turns yellow at 110. The potassium- and sodium-salts 
 are uncrystallisable. The silver-salt, C 7 H 4 AgC10 2 , is a white precipitate, consisting of 
 microscopic needles. Chlorobenzoic ether (chlorobenzoate of ethyl), C 9 H U C10 2 = 
 C 7 H 4 (C-H 5 )C10 8 , is obtained by treating the acid with alcohol and sulphuric acid, or 
 chloride of chlorobenzoyl with alcohol, and precipitating the product with water. It 
 is a liquid smelling like benzoate of ethyl, and boiling at 245 C. It dissolves in nitro- 
 sulphuric acid, and water precipitates from the solution an oil which gradually solidifies 
 into crystals, probably of nitrochlorobcnzoic ether. 
 
 Parachlorobenzoic Acid, C 7 H 5 C10 2 (Chiozza, loc. cit.) Salicylic acid is distilled 
 with perchloride of phosphorus, and the distillate rectified, when a heavy, strongly re- 
 fracting oil passes over between 200 and 250 C., which is converted gradually by cold, 
 immediately by hot water, into hydrochloric and parachlorobenzoic acids : the oil is 
 probably the chloride corresponding to the acid. Parachlorobenzoic acid forms 
 colourless shining crystals, like those of salicylic acid, from which it is distinguished 
 by giving no violet colour with ferric salts. It melts at 130 C., and sublimes unde- 
 composed : dissolves readily in hot water, and the saturated solution solidifies on 
 cooling into a mass of needles. Some of its salts differ from the corresponding chloro- 
 benzoates in the amount of water of crystallisation which they contain : thus the 
 barium-salt is anhydrous, and the calcium-salt contains 1 aq. The silver-salt may bo 
 obtained in rather large crystals. 
 
 NITEOBENZOIC ACID, C 7 H 5 N0 4 = C 7 H 5 (N0 2 )0 2 . (Plantamour [1839], Ann. Ch. 
 Pharm. xxx. 349; Mulder, ibid, xxxiv. 297; Abel, ibid. Ixiii. 313; Bertagnini, 
 ibid. Ixxix. 259; Blumenau, ibid. Ixxxvii. 127; Grerland, ibid.~s.ai. 185). Mulder's 
 method of heating benzoic acid with fuming nitric acid, is a long process. Grerland 
 recommends agitating 1 pt. benzoic acid and 2 pts. nitre with strong sulphuric acid, 
 and heating the whole till it softens : the resulting nitrobenzoic acid is purified by 
 crystallisation from boiling water. The acid is also formed by the decomposition of 
 several organic compounds : by the oxidation of hydride of nitrobenzoyl by chromic 
 acid (Bertagnini) : by boiling cinnamic acid and other cinnamyl-compounds (Plan- 
 ta*mour, Mulder), cumene^ (Abel), or dragon's blood (Blumenau), with nitric 
 acid: by heating nitrohippuric acid with hydrochloric acid (Bertagnini). Nitro- 
 benzoic acid forms colourless laminae, generally grouped together. It melts at 127 C., 
 but sublimes at 110, and if pure, leaves no residue: the vapours excite coughing. 
 When boiled it blackens and decomposes. It dissolves in 400 pts. water, at 10, 
 and in 10 pts. at 100, forming strongly acid solutions; it melts in water below 100, 
 
556 BENZOIC ACID. 
 
 to a heavy oil : is readily soluble in alcohol and ether. Strong nitric or hydrochloric 
 acid dissolves it without decomposition : but it is decomposed by prolonged boiling 
 with nitric acid. It dissolves in cold sulphuric acid : on heating the solution, some 
 nitrobenzoic acid sublimes, and near the boiling point of sulphuric acid the mixture 
 becomes red, a peculiar compound being formed (Mulder). It is not altered by 
 sublimation in dry chlorine. Perchloride of phosphorus attacks it when heated, 
 yielding chlorides of nitrobenzoyl and of phosphoryl. With sulphide of ammonium it 
 forms benzamic acid (q. v.} In the animal system it is converted into nitrohippuric 
 acid, which appears in the urine. 
 
 Nitrobenzoates are generally crystallisable and soluble in water and alcohol : they 
 explode when heated, and give off nitrobenzol. Nitrobenzoic acid is a strong acid, and 
 decomposes the salts of many other acids. The normal ammonium- salt loses ammonia 
 when heated, and yields an acid salt, which also crystallises when the solution of the 
 normal salt is evaporated : the normal salt on prolonged fusion, yields nitrobenzamide 
 (Field). The barium-salt. C 5 H 4 BaN0 4 + 2aq., forms fine crystals which lose their 
 water at 100 C. The calcium-salt contains 1 aq., which it loses at 130 180 C. 
 The copper-salt is a blue powder, which separates on cooling from a hot mixture of the 
 acid with cupric acetate : at 130 C. it loses water and some acid. The ferric salt is 
 anhydrous : it is obtained as a bulky flesh-coloured powder, when a boiling solution 
 of the acid is precipitated by ferric chloride. The normal lead-salt is obtained in crys- 
 tals when a boiling solution of the acid is added to basic acetate of lead, until a perma- 
 nent precipitate is formed : it is decomposed by washing with water, and yields basic 
 salts. 
 
 The manganese-salt contains 2 aq., one of which it loses below 100, the other at 
 133 C. The potassium- and sodium-salts crystallise with difficulty : when heated, 
 they are decomposed, emitting sparks. The silver-salt, C 7 H 4 AgN0 4 , is obtained in 
 pearly laminae, by crystallising from hot water the precipitate which nitrobenzoate of 
 ammonium gives with nitrate of silver: at 120C. it turns grey, and loses acid, at 
 250 it explodes in closed vessels, forming nitrobenzenel. The zinc-salt contains 2| aq., 
 which it loses at 140 : it crystallises from the filtrate which runs off from the gelatinous 
 precipitate formed by nitrobenzoate of ammonium with sulphate of zinc: this pre- 
 cipitate is a basic salt. 
 
 Nitrobenzoic Ethers. Nitrobenzoate of Methyl, C 8 H 7 N0 4 = C 7 H 4 (CH 3 )(N0 2 )(> 
 (Chancel, Compt. Chim. 1849, 179; Bertagnini, Ann. Ch. Pharm. Ixxix. 269.) 
 Prepared in a similar manner to nitrobenzoate of ethyl, which it resembles 
 in all its reactions. It forms small, white, nearly opaque right rhombic prisms, 
 which melt at 70 and boil at 129 C. : are insoluble in water, slightly soluble in 
 alcohol and ether, somewhat more in wood-spirit : have a faint aromatic smell, and a 
 cooling taste. 
 
 Nitrobenzoate of Ethyl C 9 H 9 N0 4 = C 7 H 4 (C 2 H 5 )(N0 2 )0 2 . (E. Kopp, Compt. rend, 
 xxxiv. 615; Chancel, loc. cit. ; Bertagnini, loc. cit. ; List and Limpricht, Ann. 
 Ch. Pharm. xc. 206.) A boiling alcoholic solution of nitrobenzoic acid is saturated 
 with hydrochloric acid : after some time water is added, and the precipitated ether is 
 agitated with hot sodic carbonate, washed with cold water, dried between filter-paper, 
 and crystallised from ether-alcohol. Bertagnini prepares it by crystallising a solution of 
 chloride of nitrobenzoyl in alcohol ; and List and Limpricht. by dropping benzoate of 
 ethyl into a mixture of 1 pt. nitric and 2 pts. sulphuric acid. It forms right rhombic 
 prisms, which melt at 42, and boil at 298 C. : smells like strawberries, and has a 
 fresh taste ; is insoluble in water, readily soluble in alcohol and ether. Boiling potash 
 decomposes it into alcohol and nitrobenzoic acid : with ammonia it forms nitroben- 
 zamide and alcohol : with sulphide of ammonium, benzamate of ethyl. 
 
 Nitrobenzoate of Dibromophenyl. (Nitrobibromobenzophenide.} C"H 7 BrN0 4 = 
 C 7 H 4 (C 6 H 3 Br 2 )(N0 2 )0 2 (List and Limpricht, loc. cit.') Separates as a resin when 
 benzoate of dibromophenyl is added to nitrosulphuric acid; the addition of water 
 scarcely precipitates anything more. It crystallises from hot alcohol in nodules, com- 
 posed of small needles : from a concentrated solution, it separates as an oil. It melts 
 between 90 and 100 C. : is insoluble in water, sparingly soluble in hot alcohol. 
 Alcoholic potash decomposes it into nitrobenzoic and dibromophenylic acids. 
 
 Nitrobenzoate of Dinitrophcnyl. C I3 H 7 N 8 8 = C 7 H 4 [C 6 H S (N0 2 ) 2 ](N0 2 )0 2 (List and 
 Limpricht, loc. cit.) Powdered benzoate of phenyl is added to cold nitrosulphuric 
 acid, whereupon it dissolves, and yellow crystals separate out, which are increased by the 
 addition of water ; these are washed, first with cold water, then with alcohol. It forms 
 a white crystalline powder, which turns yellow when heated, and melts at 150 C. : on 
 cooling, it solidifies to a yellow glass, which gradually becomes opaque. It is insoluble 
 in cold water or alcohol, sparingly soluble in hot alcohol or in ether. Heated on 
 platinum-foil, it burns with yellow smoky flame : heated in a tube, it explodes feebly. 
 It is decomposed by alcoholic potash. Sulphide of ammonium dissolves it with deep- 
 
BENZOIC ANHYDRIDE. 557 
 
 red colour : by evaporation on a water-bath, a dark-violet resinous mass is obtained 
 partly soluble in acids. 
 
 Dinitrobenzoic Acid. C 7 H 4 N 2 6 = C 7 H 4 (N0 2 ) 2 2 (Cahours, Ann. Ch. Phys. 
 [3] xxv. 30). When fused benzoic acid is gradually added to a warm mixture of nitric 
 and sulphuric acids, it dissolves with slight evolution of gas : the whole is then 
 boiled (for 1 hour, Cahours ; for 6 hours, Voit), and as soon as it begins to be turbid, 
 it is cooled and water added, which precipitates yellow flakes, which are washed with 
 water, dried, and crystallised from boiling alcohol. Dinitrobenzoic acid is thus ob- 
 tained in short shining prisms, which melt at a gentle heat, and sublime in delicate 
 needles. It is slightly soluble in cold, more in boiling, water ; readily in alcohol or 
 ether, especially on heating. It dissolves in hot nitric acid, and crystallises on cooling. 
 Cold sulphuric acid dissolves it unaltered, but decomposes it when heated strongly. 
 Sulphide of ammonium and other reducing agents convert it into diamidobenzoic acid. 
 The alkaline dinitrobenzoatcs are soluble and crystallisable : the lead- and silver-salts 
 are slightly soluble. Dinitrobenzoic ether (dinitrobenzoate of ethyl), C 9 H 9 N 2 6 = 
 C 7 H 3 (C' 2 H 5 )(N0 2 ) 2 2 , is obtained by saturating absolute alcohol with the acid, or heat- 
 ing the acid with alcohol and sulphuric acid : it forms oily drops, which solidify on 
 cooling, and are washed with dilute ammonia, and crystallised from hot alcohol. Long 
 delicate needles, with a slight yellow tinge : decomposed by strong potash, especially 
 on heating, into alcohol and potassic dinitrobenzoate. Digestion with alcoholic am- 
 monia converts it into dinitrobenzamide : sulphuretted hydrogen converts it into di- 
 amidobenzoic acid. (Voit.) 
 
 Nitrochlorobenzoic Acid. C 7 H 4 NC10 4 = C 7 H 4 (N0 2 )C10 2 (Limpricht and 
 v. Uslar, Ann. Ch. Pharm. cii. 261). When chlorobenzoic acid is dissolved in fuming 
 nitric acid, there is no immediate precipitate, but the solution continues for several 
 days to deposit colourless tables of nitrochlorobenzoic acid. These melt at 118 C. ; are 
 soluble in alcohol and ether ; melt in warm water, dissolve on boiling, and do not 
 separate out on cooling. The barium- and silver-salts only are known : the latter, 
 C 7 H 3 AgClN0 4 + Aq (?), forms small shining laminae, tolerably soluble in water. For 
 nitrochlorobenzoic ether, see above, chlorobenzoic ether. F. T. C. 
 
 BENZOIC AX.COHOXi. Syn. with BENZYLIC ALCOHOL (q. v.) 
 
 BENZOIC ANHYDRIDE. Benzoate of Benzoyl. C 14 H 10 3 = (C 7 H 5 0) 2 .O 
 (Grerhardt (1852), Ann. Ch. Phys. [3] xxxvii. 299; Wunder, J. pr. Chem. Ixi. 
 498 ; Heintz, Pogg. Ann. xcii. 458). Formed by the action of chloride of benzoyl on 
 alkaline oxalates or benzoates : also of oxychloride or perchloride of phosphorus, or 
 chloride of sulphur on alkaline benzoates, the first stage of the reaction being the 
 formation of chloride of benzoyl : also by the dry distillation of acetobenzoic and similar 
 anhydrides : 
 
 C 7 H 5 K0 2 + C 7 H 5 OC1 = C 14 H 1C 3 + KC1. 
 C 2 4 K 2 + 2C 7 H 5 OC1 = C 14 H 10 3 + 2KC1 -f CO + CO 2 . 
 2C 7 H 5 K0 2 + PCP = C I4 H'0 3 + 2KC1 + POC1 3 
 8C'H 5 K0 2 -J- 3SC1 8 = 4C 14 H'0 3 + 6KC1 + S0 4 K 2 + S 2 . 
 
 Equal parts of dry benzoate of sodium and chloride of benzoyl are heated to 130 C. on 
 a sand-bath, whereby a clear liquid is produced, from which chloride of sodium separates 
 out : the cooled mass is washed with cold water containing sodic carbonate, and crys- 
 tallised from ether or warm alcohol. The previous preparation of chloride of benzoyl 
 is avoided by employing perchloride or oxychloride of phosphorus (5 pts. oxychloride 
 to 1 pt. benzoate). Oxalate of potassium is heated with an equal weight of chloride 
 of benzoyl, with constant agitation, till the smell of chloride of benzoyl has disappeared ; 
 and the cooled mass is suspended in cold water, washed with water containing ammonia, 
 and crystallised from alcohol (G e r h a r d t). In preparing large quantities, it is better to 
 purify the product by distillation than by crystallisation from alcohol. 
 
 Benzoic anhydride forms oblique rhombic prisms, sometimes smelling of bitter-almond 
 oil or benzoic ether: it melts at 42 C., and distils undecomposed at about 310. It 
 is insoluble in cold water, soluble in alcohol and ether : the solution when fresh has no 
 acid reaction. It melts in boiling water, and remains fluid for a long time, even when 
 agitated, and is slowly converted into benzoic acid, which dissolves. Caustic alkalis 
 convert it much more rapidly into benzoic acid. Aqueous ammonia does not attack it 
 in the cold, but dissolves it on heating, forming benzamide and benzoate of ammo- 
 nium : the same reaction takes place when it is heated in dry ammonia : 
 C i4 H .o 3 + 2NIF = C 7 IFNO + C 7 H 5 (NH 4 )0-'. 
 
 Aniline acts similarly, forming phenylbenzamide. (G-erhardt.) 
 
 One atom of benzoyl in benzoic anhydride is capable of being replaced by other acid 
 radicles, forming a series of anhydrides containing benzoyl. They are obtained by the 
 
658 BENZOIC ANHYDRIDE BENZOICIN. 
 
 action of chloride of benzoyl on the alkaline salts of other monobasic acids, or, con- 
 versely, by treating alkaline benzoates with the chlorides of monobasic acid radicles. 
 They are generally decomposed by heat into two simple anhydrides : by water, and 
 more rapidly by alkalis, into two acids. 
 
 BENZOACETIC ANHYDRIDE. See ACETIC ANHYDRIDE. 
 
 BENZOANGELIC ANHYDRIDE. C 12 H 12 3 = C 5 H 7 O.C 7 H 5 0.0 (Chiozza, Ann. Ch. Phys. 
 [3] xxxix. 210). Produced by gently heating chloride of benzoyl with angelate of 
 potassium. It is a limpid oil, heavier than water, somewhat less fluid than angelie 
 anhydride, and quite neutral to test-paper. It smells like angelic anhydride, but emits 
 much more acrid vapours when heated. In a mixture of ice and salt, it thickens 
 slightly, without crystallising. 
 
 BENZOCINNAMIC ANHYDRIDE. Benzoate of Cinnamyl C i6 H 12 3 = C 7 H 5 O.C 9 H 7 O.O 
 (G-erhardt, loc. cit.) Obtained by heating 7 pts. chloride of benzoyl with 10 pts. dry 
 cinnamate of sodium, and purifying the product as in the case of benzoic anhydride. It is 
 a thick oil, colourless and odourless, which gradually becomes acid when exposed to moist 
 air. Specific gravity 1/184 at 23 C. Is decomposed by distillation, yielding a yellow 
 oil, smelling of cinnamol, which gradually deposits crystals of benzoic anhydride, and 
 an acid substance soluble in sodic carbonate. 
 
 BENZOCUMINIC ANHYDRIDE. Bcnzoate of Cumyl C 17 H 16 3 = C 7 H 5 O.C 10 H I '0.0 
 (Grerhardt, loc. cit.) Obtained like the preceding, cuminate being substituted for 
 cinnamate of potassium. Kesembles the preceding in appearance and behaviour in 
 moist air. Specific gravity 1*115 at 23 C. Is decomposed by distillation : when heated 
 in a closed vessel, it appears to volatilise without decomposition. Aqueous ammonia 
 converts it into cuminamide, and benzamide, or benzoate of ammonium. 
 
 BENZOMYRISTIC ANHYDRIDE. Benzoatc of Myristyl. C 21 H 32 3 = C 7 H 5 O.C 14 H 27 0.0 
 (Chiozza and Malerba, 1855). Obtained by heating chloride of benzoyl with my- 
 ristate of potassium. Crystallises from boiling ether, in which it is slightly soluble, in 
 shining laminae : melts at 38, and solidifies at 36 C. 
 
 BENZOOSNANTHYLIC ANHYDRIDE. Benzoate of (Enanthyl. C I4 H 18 3 = C 7 H 5 O.C 7 H 13 0.0 
 (Chiozza and Malerba, Ann. Ch. Pharm. xci. 102). Obtained by the action of 
 chloride of benzoyl on renanthylate of potassium. Colourless oil, of specific gravity 1-043 
 at 11C. ; smells like cananthylic anhydride : exposed to the air, it yields crystals of 
 benzoic acid. 
 
 BENZOPELARGONIC ANHYDRIDE. Benzoate ofPelargonyl. C 16 IP'0 3 = C 7 H 5 O.C 9 H 17 0.0 
 (Chiozza, Ann. Ch. Phys. [3] xxxix. 310). Prepared like the foregoing compounds. 
 A heavy oil, resembling pelargonic anhydride. A little below C. it solidifies to the 
 consistency of butter : is decomposed by heat into benzoic and pelargonic anhydrides. 
 
 BENZOSTEARIC ANHYDRIDE. Bcnzoate of Stearyl. C 25 H'0 3 = C 7 H 5 O.C 18 H 35 0.0 
 (Chiozza and M a 1 e r b a, loc. cit. ) Prepared by heating chloride of benzoyl and potassic 
 stearate in an oil-bath. Shining scales, which melt at 70 C. 
 
 BENZOVALERIC ANHYDRIDE. Benzoate of Valeryl. C 12 H H 3 = C 7 H 5 O.C 5 H 9 0.0. 
 (Chiozza, Ann. Ch. Pharm. Ixxxiv. 106). Chloride of benzoyl acts violently on vale- 
 rate of potassium : the product is a heavy, neutral, strongly refracting oil, smelling 
 like valeric anhydride. At about 260 C. it is decomposed into benzoic and valeric 
 anhydrides. 
 
 Substitution-products of Benzoic Anhydride. 
 
 BBNZONITROBENZOIC ANHYDRIDE. Benzoate of Nitrobcnzoyl. C 14 H 9 N0 5 = 
 C 7 H 5 O.C 7 H 4 (N0 2 )0.0. 3 pts. chloride of benzoyl are heated with 7 pts. dry nitro- 
 benzoate of sodium, and the product is purified as in the case of benzoic anhydride. 
 Crystalline : more stable than the following compound. (Grerhardt, loc. cit.) 
 
 NITROBENZOIC ANHYDRIDE. Nttrobenzoate of Nitrobenzoyl. C M H 8 N 2 7 = 
 [C 7 H 4 (N0 2 )0] 2 .0. 8 pts. nitrobenzoate of sodium are heated to 150 C. with 1 pt. 
 oxychloride of phosphorus, till the smell of chloride of nitrobenzoyl has disappeared. 
 On treating the product with cold water, a white mass is obtained, almost insoluble in 
 alcohol and ether, less fusible than nitrobenzoic acid, into which it is quickly con- 
 verted by washing with water. (Gerhardt, loc. cit.) F. T. C. 
 
 SENZ.OIC ETHERS. See p. 552. 
 
 3ENZOXCXBT. (Berthelot, Ann. Ch. Phys. [3] xli. 290.) The name given by 
 Berthelot to the artificial fats obtained by the action of benzoic acid on glycerin. 
 Glycerin being a triatomic alcohol, C 3 H 5 .H 3 .0 3 , contains 3 at. H replaceable by other 
 radicles ; and Berthelot has succeeded in obtaining the compounds in which 1 and 3 H 
 respectively are replaced by benzoyl. 
 
BENZOIN. 559 
 
 Monobenzoicin. Beneoate of Glycyl. C'H I2 O 4 = C 3 H 5 .C 7 H 5 O.H 2 .0 3 . _ Ob- 
 tained by heating benzoic acid with glycerin in a sealed tube, for forty-four hours, to 
 
 120 150 C. if the acid be in excess, to 200 C. if the glycerin be in excess ; at a 
 
 higher temperature a shorter time suffices. The product is purified by washing with 
 potassic carbonate. It is a colourless, neutral, very viscid oil, with a bitter aromatic 
 taste, and a slight balsamic smell; specific gravity 1*228 at 16 0< 5 C. _At 40 it is a 
 transparent nearly solid mass, that can be drawn out into threads ; it boils at 320, but 
 decomposes at the same time, yielding acrolein and benzoic acid. It is insoluble in 
 water, scarcely soluble in bisulphide of carbon, readily in alcohol, ether and benzene. 
 It oxidises very slightly in the air. Heated with potash it forms potassic benzoate ; 
 with ammonia, benzamide. Alcohol and hydrochloric acid convert it in the cold into 
 glycerin and benzoate of ethyl ; the same decomposition is effected when its alcoholic 
 solution is heated to 100 C. for forty-eight hours. 
 
 Tribenzoicin. Tribenzoate of Glycyl. C 24 H 20 6 = C 3 H 5 .(C 7 H 5 0) 3 .0 3 . Ob- 
 tained by heating monobenzoicin for four hours to 250 C., with 10 or 15 pts. benzoic 
 acid ; the product is washed with sodic carbonate, and repeatedly crystallised from 
 ether. Large white needles, unctuous to the touch, and fusing pretty readily. 
 Alcohol and hydrochloric acid decompose it like monobenzoicin. F. T. C. 
 
 BECTZOIN. Bitter-almond-oil-camphor. C 14 H 12 2 . (Liebig and Wohler, 
 Ann. Ch. Pharm. iii. 276; Eobiquet and Boutron-Charlard, Ann. Ch. Phys. 
 [2] xliv. 352 ; Laurent, ibid. lix. 402 ; Ixvi. 193 ; Zinin, Ann. Ch. Pharm. xxxiv. 186.) 
 - First described by Stange, 1823 (Repert. Pharm. xiv. 329) ; first correctly examined 
 by Liebig and Wohler in 1832. It is frequently contained in crude bitter-almond oil, 
 and is obtained as a by-product when the oil is purified by lime and ferrous chloride ; 
 the residue is treated with dilute hydrochloric acid, and dissolved in alcohol. Pure 
 bitter-almond oil (hydride of benzoyl) is converted into benzoin by cyanide of potas- 
 sium. To prepare benzoin from crude bitter-almond oil, the oil is mixed with its own 
 volume of a saturated alcoholic solution of potash ; after a few minutes, the whole 
 solidifies to a mass of crystals, which are purified by recrystallisation from alcohol. 
 As the amount of benzoin in different specimens of the crude oil varies considerably, 
 according to their age and to the amount of prussic acid which they contain, it is always 
 advisable to test a small portion first with alcoholic potash ; if it does not speedily 
 solidify, the crude oil had better be first freed from prussic acid, and then treated by 
 the ensuing method. Pure oil of bitter-almonds is readily converted into benzoin by the 
 addition of a dilute alcoholic solution of cyanide of potassium, or of alcoholic potash to 
 which a few drops of hydrocyanic acid have been added : this reaction is difficult to 
 account for. 
 
 Benzoin is isomeric with benzoate of benzyl, and polymeric with hydride of ben- 
 zoyl. It forms shining, transparent, colourless prisms, without smell or taste ; melts at 
 120 C., and crystallises on cooling ; if further heated, it distils undecomposed. It is 
 insoluble in cold, slightly soluble in hot water, whence it crystallises on cooling ; more 
 soluble in hot than in cold alcohol. It burns readily in the air, with a bright smoky 
 flame. Its vapour passed through a red-hot tube is reconverted into hydride of ben- 
 zoyl. When heated in chlorine, it yields benzil and hydrochloric acid. Bromine at- 
 tacks it, evolving hydrobromic acid, and forming (probably) benzil. Strong nitric 
 acid converts it into benzil. Sulphuric acid dissolves it, forming a violet solution, 
 which blackens when heated. Boiling potash does not attack it ; fused with solid 
 potash, it evolves hydrogen and yields benzoic acid : C 14 H 12 O 2 + 2KHO = 2C 7 H 5 KO - 
 4- H 4 ; boiled with alcoholic potash, it is coloured violet, and yields benzilic acid, with 
 evolution of hydrogen : C 14 H 12 2 + KHO = C 14 H n K0 3 + H 2 . With ammonia, it 
 yields, among other products, benzoinam and benzoinamide. Perchloride of phos- 
 phorus attacks it violently, yielding chloride of phosphoryl, and other products diffi- 
 cult to obtain pure. (Cahours.) 
 
 Benzoin combines with chlorides of acid radicles, yielding compounds representing 
 benzoin in which 1 H is replaced by an acid radicle. Zinin (Ann. Ch. Pharm. civ. 
 116) has obtained the following : 
 
 Acctyl-benzoin. C 16 H 14 S = C 14 H M (C 2 H 3 0)0 2 . 4 pts. of benzoin dissolve in 3 pts. 
 chloride of acetyl at 40 50 C., with evolution of hydrochloric acid ; when the solution 
 is complete, the whole is heated to 100 as long as vapours are evolved : on cooling, the 
 product slowly solidifies into crystals, which are recrystallised from alcohol or ether. 
 It crystallises from the ethereal solution in large rhombic prisms and six-sided tables ; 
 from the alcoholic solution in thin shining crystals. It is insoluble in water, melts 
 below 100, and does not always crystallise on cooling. Sulphuric or hydrochloric 
 acid, or aqueous potash does not act upon it ; with alcoholic potash it yields acetate 
 and benzoate of potassium. Strong nitric acid converts it into a mixture of two nitro- 
 produets in the form of a viscid colourless mass, insoluble in water, soluble in alcohol 
 and ether ; the solution deposits crystals. 
 
560 BENZOINAM BENZOIN-GUM. 
 
 'Benzoyl-benzoin. C 8I H 18 S = C 14 H"(C 7 H 5 0)0 2 . Chloride of benzoyldoes notact 
 upon benzoin in the cold, but at about 70 C. the benzoin dissolves and hydrochloric acid 
 is evolved ; the whole is then heated to nearly the boiling point of chloride of benzoyl 
 (196 C.), when a yellowish oily liquid is obtained, which solidifies into crystals on 
 cooling. This product is purified by being poured while liquid into cold 75 per cent. 
 alcohol, when benzoyl-benzoin separates as a crystalline powder, which is washed on a 
 filter with cold alcohol. It is insoluble in water, sparingly soluble in cold alcohol, soluble 
 in 6 pts. boiling 80 per cent, alcohol, whence it crystallises in thin colourless needles ; 
 readily soluble in ether, and crystallises by spontaneous evaporation in large shining 
 rhombic prisms ; soluble in chloride of benzoyl, and may be heated with it to 150 C. 
 without alteration. Melts at 125 C., and crystallises very slowly on cooling. Chlorine 
 does not attack it, neither does hydrochloric or dilute sulphuric acid; strong sulphuric 
 acid decomposes it. Aqueous potash does not attack it ; alcoholic potash dissolves it 
 with a violet colour, and, on boiling, converts it into benzoate and benzilate of 
 potassium. 
 
 Nitrobenzoyl-benzoin. C 21 H 15 N0 5 = C :4 H n (C 7 H 4 (N0 2 )0)0 2 . Strong nitric acid 
 (specific gravity 1*51) dissolves benzoyl-benzoin, which, if too little acid be employed, 
 crystallises out again unaltered; but if at least 1| pt. acid be taken, and the yellowish 
 solution poured into cold water, a resinous substance separates, which is a mixture of 
 two nitro-products. Ether dissolves one of these, and abandons it on evaporation as a 
 thick oil ; the other, which is nitrobenzoyl-benzoin, remains undissolved as a crystal- 
 line powder, which is recrystallised from boiling alcohol. White shining scales, com- 
 posed of rhombic tables, aggregated into scalariform groups, insoluble in water. Melts 
 at 137 C., and solidifies at 110 to an amorphous mass, which very slowly becomes 
 crystalline. Strong nitric acid dissolves it unaltered and in large quantities, especially 
 if gently heated ; on boiling the solution a new body is formed, soluble in ether, 
 which separates as a powder on cooling. F. T. C. 
 
 C 28 H 24 N 2 0. (Laurent, Compt. Chim. [1845] 37). Formed by 
 the action of alcoholic ammonia on benzoin : 
 
 2C 14 H 12 2 + 2NH 8 = C M H 24 N 2 + 3H 2 0. 
 
 Obtained, together with benzoinamide and other products, when a mixture of alcoholic 
 ammonia and benzoin is left for some months in a closed vessel. Forms white mi- 
 croscopic inodorous needles, insoluble in water ; slightly soluble in hot ether or rock- 
 oil, whence it crystallises on cooling in very bulky needles, readily soluble in hot 
 alcohol containing hydrochloric acid, whence it is partially precipitated by water, 
 entirely by ammonia. Melts when heated, and partly solidifies on cooling. Potash 
 does not attack it ; strong sulphuric acid dissolves it with red colour, and water pre- 
 cipitates orange flakes. F. T. C. 
 
 BEXrZOIXTAlKXDX:. C 42 H 36 N 4 . (Laurent [1837], Ann. Ch. Phys. [2] Ixvi. 
 189.) Formed by the action of aqueous ammonia on benzoin : 
 
 C H 36 N 4 + 6H 2 0. 
 
 Obtained as a white powder when benzoin and aqueous ammonia are left for eight 
 weeks in a closed vessel ; it is boiled in alcohol to remove excess of benzoin, and 
 crystallised from boiling ether. A white, tasteless, odourless powder, consisting of fine 
 microscopic needles ; insoluble in water, very sparingly soluble in alcohol or ether ; 
 melts when heated, and solidifies to a fibrous mass ; distils without decomposition. 
 
 F. T. C. 
 
 BEWZOIN-GUIVT. The commercial name of a resin which flows from the bark of 
 Styrax benzoin, a tree growing in Sumatra, Borneo, Java, and Siam. It comes into 
 the market in different forms. The Siamese gum occurs in irregular flat fragments, 
 about an inch long, which are reddish-yellow on the outside, white and shining in the 
 inside. The common or Calcutta-gum forms larger irregular lumps, brittle, of a dirty 
 reddish-grey or brown colour, with many light coloured spots, and often contains frag- 
 ments of wood and bark. The Siamese almond-gum appears to be a mixture of both 
 these kinds. The commercial gum has a pleasant smell, especially when heated, and 
 a sweetish, sharp, balsamic taste. It melts when heated, evolves vapours of benzoic 
 acid, and burns with a smoky flame. Specific gravity 1'063 1*092. Alcohol dis- 
 solves it completely, excepting impurities ; ether partially ; boiling water dissolves out 
 benzoic acid. 
 
 According to Unverdorben (Pogg. Ann. viii. 397), Stolze (Berl. Jahrb. Pharm. 
 xxvi. 75), Van der Vliet (Ann. Ch. Pharm. xxxiv. 177), and E. Kopp (Compt. 
 rend. xix. 1269), gum-benzoin is a mixture of three resins, whicli may be distinguished 
 as a, )3, and 7, together with benzoic acid, and. a small quantity of a volatile oil. The 
 whole of the benzoic acid cannot be driven offby heat. According to Kolbe and Laute- 
 mann (Ann. Ch. Pharm. cxv.113). some varioties of gum-benzoin, especially the almond 
 
BENZOIN-GUM BENZOLACTIC ACID. 561 
 
 gum of Sumatra, contain not benzole acid, but an acid isomeric with toluylic acid, 
 C 8 H 8 2 , which melts to a clear liquid under hot water, crystallises in forms quite 
 different from that of benzoic acid, and yields hydride of benzoyl when treated with 
 oxidising agents. 
 
 Unverdorben separates the resins in the following manner : The powdered gum is 
 extracted with boiling sodic carbonate, which dissolves out all the benzoic acid and 
 the resin 7 ; the alkaline solution is precipitated by hydrochloric acid, and the preci- 
 pitate treated with boiling water, which dissolves the acid only, leaving the resin 7 
 insoluble. The portion insoluble in sodic carbonate is washed, dried, and digested with 
 ether, which dissolves the resin a, and leaves the resin undissolved. According to 
 Kopp, the ethereal solution of a gradually deposits a small quantity of a fourth resin, 5, 
 of a reddish-brown colour. Analyses of two specimens of gum gave the following 
 results (Kopp) : 
 
 I. II. 
 
 Benzoic acid 14'0 14-5 
 
 Kesina 52'0 480 
 
 Kesin )8 25'0 28'0 
 
 Resin 7 3'0 3'5 
 
 Kesin 5 0-8 0'5 
 
 Impurities 6 - 2 6 '5 
 
 Kopp further states that the white spots in the gum are composed only of resin a, and 
 contain 8 12 per cent, benzoic acid; while the brown portions consist of resins /3 
 and 7, and contain as much as 15 per cent, acid (18 per cent, according to Unverdorben). 
 
 The resin a is readily soluble in ether and alcohol, insoluble in naphtha ; soluble in 
 potash, and not reprecipitated by excess ; insoluble in ammonia. Salts of the earthy 
 or heavy metals give, in its alkaline solution, precipitates which are insoluble in ether. 
 According to Van der Vliet it is a mixture of resins and 7, for it is decomposed into 
 these two resins by prolonged ebullition with sodic carbonate. Resin is a brownish 
 mass, soluble in alcohol, insoluble in ether and volatile oils ; soluble in potash, and re- 
 precipitated by excess ; insoluble in ammonia. Resin 7 is dark-brown, soluble in 
 alcohol, slightly in ether and volatile oils, insoluble in naphtha. Potassic carbonate 
 slowly dissolves it, and the solution is precipitated by sal-ammoniac. Its alcoholic 
 solution precipitates acetate of lead, but not acetate of copper. Resins a and , when 
 precipitated by acids from their alkaline solutions, are converted into 7 by exposure to 
 the air. 
 
 The following are the results of the analysis of these resins, and the (unreliable) for- 
 mulae, which Van der Vliet has deduced therefrom : 
 
 V. d. V. Mulder. 
 
 Resin a Carbon 72-9 71'8 73'1 
 
 Hydrogen 7'2 M 7'3 
 
 Resin Carbon 7M 71'0 717 
 
 Hydrogen 6-2 6'3 6*9 
 
 Resin 7 Carbon 73'2 73'2 73'2 
 
 Hydrogen 8-6 8-4 8-6 
 
 By the dry distillation of the resins of gum-benzoin, completely freed from benzoic 
 acid, Kopp obtained a solid substance, which he regards as the odorous principle of 
 the gum, and a rose-red distillate, which gradually becomes darker, and contains crys- 
 tals of benzoic acid ; the fluid portion appears to be hydrate of phenyl. By the same 
 process, Cahours obtained an oil, which Deville (Ann. Ch. Phys. [3] iii. 192) regards 
 as benzoate of ethyl. When they are distilled to dryness, with excess of nitric acid, 
 nitrous fumes are abundantly evolved, and a distillate is obtained, containing hydride 
 of benzoyl, benzoic acid, and hydrocyanic acid ; boiling water extracts picric acid from 
 the residue, and leaves a yellow powder, benzoeretic acid (q. v.) Sulphuric acid dis- 
 solves the resins to a common solution, whence the addition of water separates them 
 almost completely as a violet precipitate ; the acid liquid, decanted and neutralised 
 with lime yields a soluble calcium-salt. F. T. C. 
 
 BENZOLACTIC ACID. Bcmomilchsaure. C 10 H 10 4 = C 3 H 4 O.C 7 H 5 O.H.0 2 
 
 (Socoloff and Strecker, Ann. Ch. Pharm. ITYY. 46. Strecker ibid. xci. 359). 
 This acid is analogous to benzoglycollic acid, representing lactic acid in which 1 at. of 
 of basic hydrogen is replaced by benzoyl, just as benzoglycollic acid represents 
 glycollic acid in which 1 at. of basic hydrogen is similarly replaced. 
 
 It is prepared by heating 10 pts. of syrupy lactic acid with 14 pts. of benzoic acid 
 in an oil-bath to 150 C., finally raising the temperature to 200, and keeping it there 
 for some hours. Water distils over, and some benzoic acid sublimes The residue in 
 
 VOL. I. 00 
 
562 BENZOL ACTIC ACID - BENZONE. 
 
 the retort solidifies on cooling to a crytsalline mass of benzoic and benzolactic acids. 
 These are separated by partial saturation with sodic carbonate, which takes up the 
 benzolactic acid first ; the solution is filtered from the benzoic acid, and freed from 
 the small quantity of benzoic acid which it contains by agitation with ether ; on the 
 addition of hydrochloric acid, benzolactic acid separates in crystals, which are purified 
 by recrystallisation from boiling water, or from ether-alcohol. 
 
 It forms colourless tabular or spear-shaped crystals, unctuous to the touch : melts at 
 112 C., and solidifies very slowly on cooling to a crystalline mass; sublimes unde- 
 composed when heated considerably above 120. It dissolves in 400 pts. cold, and in 
 much less boiling water: when boiled with not enough water to dissolve it, the 
 excess of acid melts and the solution becomes milky on cooling, and clarifies very 
 slowly, with separation of crystals. It dissolves readily in alcohol or ether, the latter 
 removing it entirely from its aqueous solution ; after drying in the air, it does not lose 
 any water when heated to melting. By prolonged boiling in water, it is decomposed 
 with benzoic and lactic acids : the decomposition is accelerated by the addition of a 
 dilute acid. 
 
 The benzolactates are mostly crystalline, soluble in water, and closely resemble the 
 benzoates, from which, however, they are distinguished by their neutral solution not 
 being precipitated by normal acetate of lead. The barium-salt, C 10 H 9 BaO* -4- 3 aq, 
 crystallises in thin, shining, six-sided laminae, which lose their water at 100 C. The 
 silver-salt C l H 9 Ag0 4 , is a flocculent precipitate, soluble in boiling water, whence it 
 crystallises in fine needles. The sodium-salt crystallises in colourless needles from 
 boiling alcohol F. T. C. 
 
 BE3VZOLIC ALCOHOL, See BENZYLENE. 
 
 Syn. with AMARENE (q.v.) 
 
 BENZOLOUE. C 21 H 15 2 (?) (Eochleder, Ann. Ch. Pharm. xli. 94). Formed 
 together with benzostilbin, when hydrobenzamide is heated with solid potash. The 
 mixture must be heated till it blackens ; the product is powdered, extracted with water, 
 washed with cold hydrated alcohol, and the residue dissolved in strong sulphuric acid. 
 The blood-red solution thus formed becomes greenish-yellow on addition of dilute 
 alcohol, and deposits small crystals of benzolone : on addition of water, it separates in 
 the uncrystalline state. It is insoluble in water or alcohol ; melts at 248 C., and 
 sublimes almost without decomposition, when more strongly heated. Strong nitric 
 acid dissolves it with a reddish-yellow colour, and it is reprecipitated by water ; fuming 
 nitric acid decomposes it, forming a yellowish resin with evolution of nitrous fumes. 
 It is not attacked by aqueous potash. Rochleder's analyses give a mean composition of 
 C 63-5, H 5-2. / F. T. C. 
 
 BEWZOIVEERCUR.A.IV1IDE. See BEXZAMIDE. 
 
 BENZOMYRISTIC ANHYDRIDE. See BENZOIC ANHYDRIDE. 
 
 BETJZOKTE. Benzophenone. Phenyl-benzuyl. C 13 H 10 = C 6 H 5 .C 7 H 5 (Peligot* 
 Ann. Ch. Phys. [2] Ivi. 69. Chancel, Compt. rend, xviii. 83.; Ann. Ch. Pharm. 
 ITTY. 25). The acetone of benzoic acid ; it is formed by the dry distillation of benzoate 
 of calcium: 
 
 2C 7 H 5 Ca0 2 = C 1S H 10 + COW. 
 
 Dry benzoate of calcium is mixed with ^ of its weight of quick lime, and distilled in 
 an iron mercury bottle, fitted with a bent gun-barrel. The red liquid which passes 
 over (which Peligot called benzone), contains, besides benzone, benzene, hydride of 
 benzoyl, and two solid hydrocarbons isomeric with naphthalin. On distilling it in a 
 tubulated retort, benzene first passes over ; and the temperature rises rapidly : the 
 portion which comes over at 315 325 C. is collected apart, and consists of nearly 
 pure benzone, which solidifies on cooling, and may be obtained quite pure by recrystal- 
 lisation from ether-alcohol. 1 kilogr. benzoate of calcium yields about 250 grms. 
 benzone. 
 
 Benzone forms colourless, transparent crystals, often of considerable size, belonging 
 to the trimetric system. It melts at 46 C. to a thick oil which does not solidify 
 unless it be agitated ; boils at 315 and distils undecomposed : its vapour is very inflam- 
 mable, and burns with a bright flame. It has a pleasant smell, somewhat like that of 
 benzoic ether. It is very soluble in ether, less so in alcohol, not at all in water ; strong 
 nitric or sulphuric acid dissolves it abundantly, and water reprecipitates it unchanged. 
 When heated with soda-lime to about 260 C. it is decomposed, yielding sodic benzoate 
 and benzene, but not a trace of hydrogen : 
 
 C 6 H 5 .C 7 IPO + NaHO = C 6 H 5 .H + C 7 H 5 O.Na.O. 
 Dinitrobenzonc. Dintrobcnzophenone. C 18 H 8 N 2 5 = C W H 8 (N0 2 ) 2 O. Warm fuming 
 
BENZONITRILE. 563 
 
 nitric acid converts benzone into a thick oil, which solidifies very slowly ; other dis- 
 solves it and deposits it speedily in the form of a yellowish crystalline powder, which 
 is dinitrobenzone. Reducing agents convert it into diphenyl-carbamide (flavine) : 
 
 C 1S H 8 N 2 5 + 6H 2 S = C I3 H 12 N 2 + 4H 2 + S 6 . 
 flavine. 
 
 Of the two hydrocarbons, isomeric with naphthalin, mentioned above, one cry- 
 stallises in large needles, fusible at 92 C., the other, much less soluble in alcohol 
 and ether, forms small nodules fusible at 65. The former is readily obtained by 
 dissolving in strong sulphuric acid the liquid obtained by the dry distillation of 
 calcic benzoate ; it immediately solidifies on the surface, and is removed, washed, dried 
 by filter paper, and crystallised from hot alcohol. The latter is best prepared by the dry 
 distillation of potassic benzoate with potash-lime : it then passes over alone, in solution 
 in benzol, which is distilled off in a water-bath, and the residue crystallised from 
 alcohol. It is also formed together with benzol, when ammonic benzoate is passed 
 over heated baryta. F. T. C. 
 
 BElffZOXriTRXX.E. Cyanide of Phcny I C 7 H 5 N = C 6 H S .CN" (Fekling (1844), 
 Ann. Ch. Pharm. xlix. 91. Limpricht and v. Uslar, ibid. Ixxxviii. 133). Ben- 
 zonitrile is obtained by various methods : 1. By the dry distillation of benzoate of 
 ammonium, or by heating benzamide, either alone or with caustic lime, or baryta, 
 phosphoric anhydride, or perchloride of phosphorus: the reaction in all these cases 
 consists in the abstraction of the elements of water : 
 
 C 7 H 5 O.NH 4 .0 - 2H 2 = C 7 H 5 N. 
 Benz. amm. 
 
 N.C 7 H 5 O.H 2 - H 2 = C 7 H 5 N. 
 
 Benzamide. 
 
 2. By heating hippuric acid, either alone (Limpricht), or with chloride of zinc 
 (Grossmann). 3. By the action of chloride of benzoyl or benzoic anhydride on benza- 
 mide, or by heating beuzamide with potassium (see BENZAMIDE). 4. By the action of 
 chloride of benzoyl on oxamide (Chiozza): 
 
 C 7 H 5 O.C1 + N 2 .C 2 2 .H 4 = C 7 IPN + CNH + HC1 + CO 2 + H 2 0. 
 
 or on eulphocyanate or cyanate of potassium (Schiff, Ann. Ch. Pharm. xcix. 117, 
 ci. 93) : 
 
 2C 7 H 5 O.C1 + 2CNSK = 2C 7 H 5 N + 2KC1 + CO 2 + CS 2 . 
 
 6. By heating benzoic anhydride with cyanate or sulphocyanate of potassium (Schiff) : 
 2CNOK = 2C 7 H 5 N + C0 3 K 2 + CO 2 . 
 
 6. By the action of mercuric oxide on thiobenzamide (q. v. under BENZAMIDE). 
 
 Preparation. 1. When dry benzoate of ammonium is heated in a retort, ammonia 
 escapes, benzoic acid sublimes, and water passes over with a few oily drops of benzo- 
 nitrile ; as most of the benzonitrile remains in the fused residue in the retort, this is 
 covered with water (to which a little ammonia is added), again distilled to dryness, 
 and the operation repeated as long as any oil passes over with the water: 12 oz. 
 benzoic acid yield in 5 days, 6 oz. impure benzonitrile. This product is washed with 
 dilute hydrochloric acid, then with water, dried over chloride of calcium, and recti- 
 fied (Fehling). According to Laurent and Chancel (Compt. chim. 1849, 117), 
 benzonitrile is more easily prepared by passing the vapour of ammonic benzoate over 
 heated baryta. 2. One pt. dry hippuric acid is mixed in a warm mortar with an equal 
 bulk of quartz-sand and 2 pts. chloride of zinc dried as completely as possible, and the 
 mixture is heated in a dry retort to 3 00 350C.: benzontrile then distils over, carbonic 
 anhydride escapes, and a little carbon is deposited ; 100 grms. hippuric acid (the utmost 
 precautions being taken to exclude moisture) yielded 33 40 grms. benzonitrile; 
 calculation requires 57 grm. (Grossmann, Ann. Ch. Pharm. c. 72). 3. According to 
 Buckton and Hofmann, benzonitrile is best prepared by distilling benzamide with 
 phosphoric anhydride. 
 
 Benzonitrile is a clear, colourless, strongly refracting oil, smelling like bitter-almond 
 oil, and having a burning taste; specific gravity 1-0230 at 0, 1*0084 at 16-8 C. 
 Kopp). At higher temperatures it is less dense than water, for it sinks in cold water, 
 but rises to the surface when heated. It boils at 190-6 C. with the barometer 
 at 733'4 mm. (Kopp), and distils undecomposed : its vapour density is 37 (expt.) ; 
 its coefficient of refraction is 1-503 (Reusch). It dissolves in 100 pts. boiling 
 water, and separates out again on cooling; it mixes with alcohol and ether in afl 
 proportions. Sulphur dissolves in it with the aid of heat, and crystallises out on 
 cooling. 
 
 o o 2 
 
564 BENZONITRILE BENZOSALICYLAMIC ACID. 
 
 Benzonitrile burns with a bright smoky flame. Cold aqueous potash does not 
 attack it, but on boiling, ammonia is evolved and potassic benzoate formed ; a similar 
 decomposition is effected by dilute acids. Strong sulphuric add dissolves it, and on 
 heating, sulphobenzoic and disulphobenzolic acids, and acid sulphate of ammonium 
 are formed, and carbonic anhydride is evolved : (Buck ton and Hofmann) : 
 
 2C 7 H 5 N + 5S0 4 H + H 2 = C 7 H 6 S0 5 + C S H 6 S 2 6 + 2(NH 4 .H.S0 4 .) + CO 2 . 
 
 "With fuming nitric acid it forms a substitution-product (see below); when heated 
 with potassium in a sealed tube, it assumes a carmine colour, and at 240 C. yields a 
 sublimate of fine needles ; water extracts cyanide of potassium from the product, and 
 the residue yields on distillation, a green oil smelling of creosote, in which crystals 
 again form (Bingley, Chem. Gaz. 1854, 329). With sulphide of ammonium, it forms 
 thiobenzamide (q. v. under BENZAMIDE). 
 
 Substitution-products of Benzonitrile. 
 
 Chlorobemonitrile or Cyanide of Chlorophenyl, C 7 H 4 C1N, has not been obtained 
 by the action of chlorine on benzonitrile ; but it is the principal product when sulpho- 
 benzamide or sulphobenzamic acid is distilled with perchloride of phosphorus. The 
 distillate is mixed with potash, and rectified, when chlorobenzonitrile passes over with 
 aqueous vapour, and collects in the receiver, forming crystals which are obtained in large 
 colourless prisms by recrystallisation from alcohol or ether. It smells like bitter-almond 
 oilj is insoluble in water, but readily soluble in alcohol or ether ; melts below 40, and 
 aolidifies at 36 C., volatilises slightly at the ordinary temperature, more rapidly at 
 a gentle heat. Prolonged boiling with dilute nitric acid converts it into chlorobenzoic 
 acid; heated to 100 with ammonia in a sealed tube, it yields chlorobenzamide. 
 (Limpricht.) 
 
 Nitrobenzonitrile or Cyanide of Nitrophenyl. C 7 H 4 N 2 2 = C 6 H 4 (N0 2 )K Pre- 
 cipitated as a white solid body when benzonitrile is heated gently with fuming nitric 
 acid and water added to the solution ; it is tolerably soluble in hot water, and sepa- 
 rates on cooling in small white silky needles, soluble in acids, and reprecipitated by 
 water. When heated, it evolves irritating vapours, and leaves a residue of carbon. 
 When boiled with acids or alkalis, it yields ammonia and a nitrobenzoate. It cannot be 
 obtained by the dry distillation of nitrobenzoate of ammonium (Gerland). F. T. C. 
 
 BENZOItf ZTROBEUZOIC ANHYDRIDE. See BENZOIC ANHYDRIDE. 
 
 BENZOlVrrrRQCinVIIDE. See CuMYLAMINE. 
 
 BENZO<ErJANTHYI,IC ANHYDRIDE. See BENZOIC ANHYDRIDE. 
 
 BENZOPELARGONIC ANHYDRIDE. See BENZOIC ANHYDRIDE. 
 
 BENZOPHE10TDE. Syn. with BENZOATE OF PHENYL. See BENZOIC ACID. 
 
 BENZOPHENONE. Syn. with BENZONE (q. v.) 
 
 BENZOPIPERIDE. See PIPEBIDINE. 
 
 BENZOPROPYIiENYIc. Syn. with BENZOATE OF ALLYL. See BENZOIO ACID. 
 
 BENZOSAIiICIN. Syn. with POPTILIN (q. v.) 
 
 BEBTZOSAXiICYIiAIMCIC ACID. Benzosalicylamide. C l4 H n NO s =N.H.C 7 H s O. 
 C 7 H 4 O.H.O. (Gerhardt and Chiozza, Compt. rend, xxxvii. 86 ; Limpricht, Ann. 
 Ch. Pharm. xciv. 249.) When equivalent quantities of salicylamic acid and chloride of 
 benzoyl are heated together to 120 145 C., as long as hydrochloric acid escapes, the 
 product remains liquid a long time after cooling, but crystallises on adding a few drops of 
 alcohol or ether ; it is washed with ether, and dissolved in boiling alcohol, whence it 
 crystallises in slender needles united in flocks. It is sparingly soluble in alcohol, 
 even on boiling. When heated, it gives off water, and is converted into benzo- 
 salicylimide. It is readily soluble in ammonia, and is reprecipitated unchanged 
 on evaporating the solution, or on addition of an acid. It dissolves in the fixed 
 alkalis, forming deep yellow solutions, but is generally decomposed into benzoate and 
 salicylate. It is attacked by chloride of benzoyl, yielding a crystalline product, 
 which appears to be converted into benzosalicylamic acid by the addition of water or 
 alcohol. After fusion, it is no longer completely soluble in hot ammonia ; the yellow 
 residue is soluble in alcohol, forming a yellow solution which deposits on evapora- 
 tion small crystals, apparently of an ammonium-salt : the solution is decolorised by 
 hydrochloric acid. 
 
 Bcnzosalicylamates. The ammoniacal solution of the acid forms a light-yellow pre- 
 cipitate with normal acetate of lead, and a light-blue with sulphate of copper. With 
 nitrate of silver, it forms the silver-salt, C 14 H 10 AgN0 3 , a yellow precipitate, which 
 becomes heated on contact with chloride of benzoyl, forming a viscous product, which 
 dissolves in alcohol, leaving-a residue of chloride of silver. 
 
BENZOSALICYLAMIDE BENZOYL. 565 
 
 If salicylic acid be regarded as monobasic, this compound becomes benzosalicylamide, 
 N.C 7 H 5 O.C 7 H 5 0. 2 H. R T. C. 
 
 BEr/ZOSAXiXCYXAIVXXDE. See BENZOSALICYLAMIC ACID. 
 
 BENZ.CSALICYI.IC ACID. C 14 H 10 4 = C 7 H 4 O.C 7 H 5 O.H.O*. (Gerhardt 
 (1852), Ann. Ch. Phys. [3] xxxvii. 322.) Formed by the action of chloride of benzoyl 
 on salicylate of potassium, as a viscous mass difficult to purify, soluble in ether, de- 
 composed by boiling water into benzoic and salicylic acids. By dry distillation, it 
 yields benzoate of phenyl, and other products soluble in potash. 
 
 This compound is analogous to benzoglycollic and benzolactic acids. If salicylic acid 
 be regarded as monobasic, it becomes benzosalicylic anhydride, C 7 H 5 O.C 7 H 5 O 2 .0. 
 
 F. T. C. 
 
 BEXrZOSAXiXCYX.XMXl>B. See BENZAMIDE. 
 
 BEXTZOSTEARXC ANHYDRIDE. See BENZOIC ANHYDRIDE. 
 
 C 14 H'0 (?) (Rochleder, Ann. Ch. Phann. xli. 93). The 
 yellow powder obtained by fusing hydrobenzamide with solid potash consists of a 
 mixture of three substances, a peculiar yellow oil, benzostilbin, and benzolone : the pro- 
 portions of these three compounds vary with the duration of the fusion, benzolone not 
 being formed at all unless the mixture has been heated till it blackens. The two former 
 are separated from the third by alcohol, in which benzolone is insoluble. The alcoholic 
 solution is mixed with a little hydrochloric acid, when it becomes red, but is decolo- 
 rised by standing, and deposits benzostilbin in small crystals ; the same result is pro- 
 duced more rapidly by passing chlorine into the solution. The crystals may be 
 obtained larger by the slow evaporation of their solution in ether. When quite free 
 from the yellow oil, they are but slightly soluble in alcohol. They melt at 244'5 C., 
 and sublime when further heated, being in great measure decomposed. They dissolve 
 with a red colour in sulphuric acid, and may be boiled without decomposition in 
 aqueous potash of 1-2 specific gravity. Rochleder's analysis gives 86'5 86'6 C, 
 5-253 H. F, T. C. 
 
 BEXTZOSITCCXiarxxx. C 14 H 13 8 . The name given by Van Bemmelen (J. pr, 
 Chem. Ixix. 84) to a glyceride or artificial fat obtained by heating glycerin to 200 C. 
 with benzoic and succinic acids. It is a soft dark-brown mass, which is decomposed by 
 long boiling with water or alcohol, more rapidly in presence of an alkali, into benzoate 
 and succinate. It represents glycerine in which 1 at. H is replaced by benzoyl and 
 2 at. by succinyl, C 3 H 5 (C 7 H 5 0)(C 4 H 4 O a )0 3 . F. T. C. 
 
 BEBTZOSUXPHOPHZHJAIKXC ACID. See BENZ AMIDE. 
 BENZQSUX.FHO?HENAXV2XDE. See BENZAMIDE 
 
 BEltfZOSUIiPHOPHENAIVIIDYI., CHLORIDE, and AMIDE. See BENZAMIDE. 
 BENZOSULPHOPHEWARG-ENTAIVIIDE. See BENZAMIDE. 
 BEKTZOSUX,PKOFHEI?Y:LSODAIVKIDE. See BENZAMIDE. 
 BENZOSYIiAVTIXiXDE. See BENZYLENE-PHENYLAMINE. 
 
 BEXTZOTARTARXC ACXT. C !1 H 10 7 = (C 4 H0 4 )".C 7 H 5 O.H.O 2 . (Dessaignes, 
 J. de Pharm. [3] xxxii. 47.) Obtained by heating a mixture of equivalent quantities 
 benzoic and tartaric acids to 150 C. The acids melt at first without mixing, but at 
 last form a homogeneous brown mass. When this is dissolved in boiling water, some 
 benzoic acid crystallises out ; the mother-liquor is partially neutralised by sodic carbo- 
 nate, decolorised by animal charcoal, and acidulated with hydrochloric acid. After 
 some time, nodular masses separate out, which are formed of microscopic crystals, and 
 are not altered in form by recrystallisation. The acid is more soluble in cold water 
 than benzoic acid, but less soluble in alcohol ; its solution has no smelL No sublimate 
 is formed when it is heated to the melting-point of benzoic acid ; when it is further 
 heated, benzoic acid sublimes, and the brown residue smells of heated tartaric acid. 
 A cold saturated solution of the acid does not precipitate lime-water, ferric chloride, 
 or nitrate of silver ; it slightly precipitates a concentrated solution of normal acetate 
 of lead. When neutralised with ammonia, it gives a pale yellow precipitate with ferric 
 chloride, but does not precipitate chloride of calcium. When its solution is one-fourth 
 neutralised with ammonia, it gives with nitrate of silver, a precipitate, which at first 
 is redissolved : it contains 46-35 per cent, silver, corresponding to the formula 
 O u H 8 Ag 2 7 . From this the acid would appear to be dibasic, in which case it is not 
 analogous to benzoglycollic and benzolactic acids. F. T. C. 
 
 BENZOVAXiERXC ANHYDRIDE. See BENZOIC ANHYDRIDE. 
 
 Z.OYL. C 7 H 5 0. The hypothetical radicle which, according to Liebig and 
 o o 3 
 
666 BENZOYL: BROMIDE CHLORIDE. 
 
 Wohler' s original suggestion, is usually considered as existing in benzoic acid and 
 many of its kindred compounds, benzoic acid, C 7 H 6 2 , being regarded as hydrate of 
 benzoyl, C 7 H 5 O.H.O, bitter-almond oil, C 7 H 6 O, as hydride of benzoyl, &c. This view 
 explains the reactions of the majority of benzoyl-compounds in a far more satisfactory 
 manner than that of Berzelius, who, in accordance with his opinion that oxygen never 
 entered into the composition of an organic radicle, considered C 7 H 5 as the radicle of 
 this group of compounds. The readiness with which many benzoyl-compounds pass 
 into phenyl-compounds renders it probable that benzoyl should be regarded as a 
 compound of phenyl, C 6 H 5 , with carbonyl, CO ; just as acetyl may be regarded as a 
 compound of methyl and carbonyl. One or more atoms of hydrogen in benzoyl is 
 capable of being replaced by a monatomic radicle (Cl, Br, NO 2 , &c.) forming what 
 may be called secondary or substitution-radicles (chlorobenzoyl, C 7 II 4 C10, nitrobenzoyl, 
 C 7 H 4 (NO 8 )0, &c.), which may be supposed to exist in chloro- or nitro-benzoic acid, &c. 
 Benzoyl has not yet been isolated. Benzil, which has the same composition, does not 
 exhibit any analogy with other organic radicles. F. T. C. 
 
 BENZOYL, BROMIDE OP. Brombenzaldid. C 7 H 5 O.Br. (Li ebig and Wohler, 
 Ann. Ch. Pharm. iii. 266.) When hydride of benzoyl is mixed with bromine, heat is 
 evolved, and hydrobromic acid given off: the mixture is then heated, to free it com- 
 pletely from hydrobromic acid and excess of bromine. Thus obtained, bromide of 
 benzoyl is a soft, brown, broadly laminar, crystalline mass, semifluid at the ordinary 
 temperature, and melting at a very gentle heat to a brownish-yellow liquid. It has 
 a faint aromatic odour, somewhat like that of chloride of benzoyl, and is readily soluble, 
 without decomposition, in alcohol and ether. When heated with water, it melts, and 
 remains at the bottom, as a brownish oil, which is decomposed into benzoic and 
 hydrobromic acids only by prolonged boiling. It fumes slightly in the air, strongly 
 when heated, and burns with a bright sooty flame. F. T. C. 
 
 BECTZOYX., CHLORIDE OP. Chlorbtnzaldid. C 7 H 5 O.C1. (Liebig and 
 Wohler (1832), Ann. Ch. Pharm. iii. 262; Cahours, Ann. Ch. Phys. [3] xxii. 
 334; Grerhardt, ibid, xxxvii. 291). Formed: 1. by the action of chlorine on 
 hydride of benzoyl (L. and W.) 2. By heating perchloride of phosphorus with 
 benzoic acid (Cahours). 3. By the action of oxychloride of phosphorus on benzoates 
 (Grerhardt). Also in small quantities, by the action of chlorine on mandelic acid, 
 or on benzoate of methyl or ethyl (Malaguti, Ann. Ch. Phys. [2] Ixx. 374), and on 
 cinnamein (Fremy, ibid. 180). 4. By heating benzoic acid to 200 C. with a mixture 
 of chloride of sodium and anhydrous acid sulphate of sodium or potassium. 
 
 Preparation. 1. Dry chlorine is passed into hydride of benzoyl, the liquid being 
 gradually heated to boiling, till no more hydrochloric acid is evolved: the product is 
 freed by heat from dissolved chlorine. 2. A better and easier method is to warm equi- 
 valent proportions of benzoic acid (122 pts.) and perchloride of phosphorus (209 pts.) 
 in a tubulated retort ; a violent reaction takes place, hydrochloric acid is evolved, and 
 a mixture of chlorides of benzoyl and phosphoryl distils over, heat being gradually 
 applied. The mixed chlorides are separated by fractional distillation: at 110C., chloride 
 of phosphoryl passes over ; from 110 to 196, a mixture of the two chlorides ; and from 
 196 to 200, nearly pure chloride of benzoyl, which is readily freed from traces of oxy- 
 chloride by washing with water, and dried over chloride of calcium. 3. Sodic ben- 
 zoate is treated an a similar manner with oxychloride of phosphorus : the reaction is 
 violent even in the cold, and if the oxychloride be slightly in excesss, chloride of 
 benzoyl and sodic phosphate are the only products : 
 
 3C 7 H 5 Na0 2 + POCP = 3C 7 H 5 O.C1 + P0 4 Na 3 , 
 
 otherwise benzoic anhydride is also formed. The distillate below 196 obtained in (2) 
 may advantageously be employed for this purpose. 
 
 Chloride of benzoyl is a clear colourless liquid, with a peculiar smell, which resem- 
 bles that of horse-radish and makes the eyes water. Specific gravity 1-196 (L. and 
 W.); 1-25 at 15 C. (Cahours): boils at 196: vapour-density (expt.) 4'987 
 (Cahours) ; 4'901 (calc.). It is insoluble in water, but is decomposed slowly by cold, 
 and quickly by hot water, into benzoic and hydrochloric acid : the same decomposi- 
 tion is slowly effected when it is exposed to moist air. It is decomposed by alcohol, 
 with evolution of heat, into benzoic ether and hydrochloric acid : it does not act 
 upon pure ether. It is soluble in all proportions in bisulphide of carbon, without 
 decomposition, and with the aid of heat dissolves sulphur and phosphorus, which 
 crystallise out on cooling. 
 
 It burns with a bright, green-edged, very smoky flame. When boiled with aqueous 
 alkalis, it is immediately decomposed into benzoate and chloride, but it may be 
 distilled without alteration over anhydrous lime or baryta. With dry ammonia or am- 
 monic carbonate, it forms benzamide and chloride of ammonium; it is similarly decom- 
 
BENZOYL: CHLORIDE. 567 
 
 posed by phenylamine and other alkaloids, yielding phenylbenzamide, &c. It is decom- 
 posed by certain metallic bromides, iodides, sulphides, and cyanides, yielding bromide, 
 iodide, sulphide, or cyanide of benzoyl. With sulphocyanate of potassium, it evolves 
 heat, and yields carbonic anhydride and sulphide, and benzonitrile (Schiff, Ann. 
 Ch. Pharm. xcix. 117): probably owing to the decomposition of sulphocyanate of 
 benzoyl : 
 
 2(CNS.C 7 H S 0) = 2C 7 H 5 N + CO 2 + CS 2 (Limpricht). 
 
 It is not attacked by potassium. When heated with hydride of copper, it yields 
 hydride of benzoyl and subchloride of copper (Ch iozza). With chloride of aluminium, 
 it forms a crystalline compound, but not with the chlorides of copper, magnesium, or 
 zinc: it is decomposed by perchloride of tin (Casselmann). With the alkaline salts 
 of many organic monobasic acids, it yields an alkaline chloride and an anhydride, 
 e. g. with sodic bcnzoate, benzoic anhydride ; with sodic pelargonate, benzopelargonic 
 anhydride, &c. (Gerhard t). Heated with formate of sodium, it yields carbonic 
 oxide, chloride of sodium, and benzoic acid : 
 
 CHNaO 2 + C 7 H 5 OC1 = CO + NaCl + C 7 H C 2 (Gerhardt). 
 
 Heated with potassic oxalatc, it yields benzoic anhydride, potassic chloride, and car- 
 bonic oxide and anhydride (Gerhardt) with oxamide, benzonitrile and other products 
 (see BENZONITRIL), with most amides, a secondary or tertiary amide containing benzoyl. 
 
 When finely powdered aldehyde-ammonia is gradually added to chloride of benzoyl, 
 sal-ammoniac and benzoic acid are formed, together with a substance which crystal- 
 lises from hot alcohol in needles having the composition C 16 H 16 N 2 2 , isomeric (perhaps 
 identical) with hipparaffin. It is insoluble in water, readily soluble in hot alcohol or 
 ether ; is fusible, and sublimes partly undecomposed ; is slowly decomposed by boiling 
 potash or sulphuric acid into benzoic acid and a brown resin ; is not attacked by boiling 
 with water and peroxide of lead, till sulphuric acid is added, when aldehyde is evolved 
 and benzamide formed; is similarly decomposed by nitrous acid. (Limpricht, Ann. 
 Ch. Pharm. xcix. 119.) 
 
 Pentachloride of phosphorus dissolves in hot chloride of benzoyl, and is deposited on 
 cooling (Gerhardt). According to Schischkoff and Hosing (Compt. rend. xlvi. 
 867), when equivalent quantities of the two substances are heated together in a sealed 
 tube to 200 C. for some days, a compound, C 7 H 5 OC1 3 , is formed, which they call per- 
 chloride of benzoyl. The contents of the tube are heated in a retort to about 110 C., 
 washed first with strong potash, and then with water, and dissolved in alcohol ; the 
 addition of water precipitates the compound as a yellowish neutral oil, heavier than 
 water, soluble in alcohol or ether. It blackens at 130 140, and cannot be distilled 
 without decomposition. It is decomposed when heated with water in a sealed tube, but 
 not by mere contact with water or aqueous or solid potash : it is also decomposed by 
 fuming nitric acid, evolving nitrous fumes ; with acetate of silver in the cold it yields 
 chloride of silver. 
 
 By the action of chlorine on benzoate of ethyl (q. v.) a compound is obtained, having 
 the composition C 18 II Ifi Cl 6 O s , which may be regarded as a compound of chloride of 
 benzoyl with tetrachlorovinic ether, C 18 H 16 C10 3 = 2C 7 H 5 OC1.C 4 H 6 C1 4 0. It is a 
 colourless liquid, boiling at 188 190 C., of specific gravity 1-346 at 10*8, smells like 
 chloride of benzoyl, fumes in moist air, and is slowly decomposed by water into hydro- 
 chloric, benzoic, and acetic acids. (Malaguti, Ann. Ch. Phys. [2] Ixx. 374.) 
 
 Chloride of benzoyl appears to form a compound with hydride of benzoyl. (See 
 BENZOYL, HYDBIDE OF.) 
 
 Substitution-products of Chloride of Benzoyl. 
 
 Chloride of Chlorobenzoyl. C 7 H 4 C1 2 ** C 7 H 4 C10.C1. (Limpricht and v. 
 Uslar, Ann. Ch. Pharm. cii. 262). Obtained: 1. By the action of perchloride of 
 phosphorus on chlorobenzoic acid. 2. By the decomposition of chlorosulphobenzoic 
 acid: 
 
 C 7 H<C1 2 SO S = C 7 H 4 C1 2 + SO 2 . 
 
 1 at. sulphobenzoic acid is heated with 2 at. perchloride of phosphorus, as long as any- 
 thing distils over; by repeated rectification of ^ the distillate, a yellowish liquid is ob- 
 tained, which boils at 285 C., and consists of impure chloride of chlorobenzoyl, which 
 cannot be purified by distillation. As obtained by (1) it is a clear, colourless, strongly- 
 refracting liquid, which boils at 225 C. : is slowly decomposed by boiling water into 
 chlorobenzoic and hydrochloric acids, and quickly by strong aqueous ammonia, into 
 chlorobenzamide and chloride of ammonium. 
 
 By the distillation of salicylic acid with perchloride of phosphorus Chiozza (Ann. 
 
 o o 4 
 
568 BENZOYL: CYANIDE HYDRIDE. 
 
 Ch. Phys. [3] xxrvi. 102) obtained a compound isomeric with the foregoing, whiell 
 may be called chloride of parachlorobenzoyl : 
 
 C'H 6 S + 2PC1 9 = C 7 H 4 C1 2 + 2POC1 3 + 2HCL 
 
 The distillate, which is probably not quite pure, is a heavy strongly -refracting liquid, 
 with a suffocating smell, and decomposed slowly by cold, immediately by hot water, 
 into parachlorobenzoic and hydrochloric acids: when gently heated with salicylous 
 acid, it yields hydrochloric acid and salicylide of benzoyl. This reaction has not yet 
 been explained. 
 
 Chloride of Nitrobenzoyl. C'IFCINO 3 = C 7 H 4 (N0 2 )O.C1. (Cahours (1848), 
 Ann. Ch. Phys. [3] xxiii. 339; Bertagnini, ibid. [3] xxxiii. 465.) Formed by the 
 action of chlorine in the sunshine on hydride of nitrobenzoyl. Also by heating nitro- 
 benzoic acid with perchloride of phosphorus ; a mixture of the chlorides of phosphoryl 
 and nitrobenzoyl distils over, which is rectified, and the portion which passes over 
 last, is washed with water, dried over chloride of calcium, and again distilled. It is a 
 yellow liquid, heavier than, and insoluble in, water, something like chloride of benzoyl, 
 and boiling at 265 268 C. It is gradually decomposed in moist air into nitroben- 
 zoic and hydrochloric acids. It is similarly decomposed by strong boiling potash. With 
 ammonia, it forms nitrobenzamide ; with phenylamine, phenylnitrobenzamide. With 
 alcohol or wood-spirit, it forms nitrobenzoate of ethyl or methyl : it is not decomposed 
 by ether. F. T. C. 
 
 BENZOYL, CYANIDE or. C 8 H 5 NO = C 7 H 5 O.CN. (LiebigandW6hler(1832), 
 Ann. Ch. Pharm. iii. 267 ; H. Strecker, ibid. xc. 62.) When chloride of benzoyl is dis- 
 tilled with cyanide of mercury, a yellow oil passes over, which may be obtained colour- 
 less by rectification (L. and W.) ; after a time, it solidifies to a crystalline mass, which, 
 after washing with water as long as any mercury-salt is washed out, and drying with 
 filter-paper and over sulphuric acid, leaves pure cyanide of benzoyl. It is a colourless 
 crystalline body, which melts at 31 C., and crystallises by slow cooling in tables an 
 inch long ; it has a pungent odour, exciting tears ; boils at 206 208 C. ; is heavier than 
 water ; is inflammable, and burns with a very smoky flame. It is very slowly decom- 
 posed by water in the cold, and not rapidly, even on heating : is decomposed by aqueous 
 potash ; also by ammonia, into benzamide and cyanide of ammonium ; and by zinc and 
 hydrochloric acid, into hydride of benzoyl and benzoin. F. T. C. 
 
 BEWZOYI., HYDRIiDE OP. Benzaldine. Bitter-Almond Oil. Oxide of 
 Picramyl. Oxide ofStilbene. C 7 H 6 = C 7 H 5 O.H. (Liebig and Wohler (1832), 
 Ann. Ch. Pharm. xxii. 1.) The principal constituent of crude bitter-almond oil, the vo- 
 latile oil which is obtained by distilling bitter-almonds with water (see BITTEE-AI-MOND 
 OIL). It is also formed by the decomposition of many organic substances. 1. By the 
 oxidation of amygdalin, amygdalic acid, benzylic alcohol (Cannizzaro, Ann. Ch. 
 Pharm. Ixxxviii. 180), cinnamon-oil, cinnamic acid (Mulder, Dumas, andP^ligot), 
 and gum-benzoin, by nitric acid ; of stilbene and styracene by aqueous chromic acid 
 (Laurent); of mandelic acid, styrone, and (with several other products) of casein, al- 
 bumin, fibrin, and gelatine, by sulphuric acid and binoxide of manganese. 2. By the 
 action of hydride of copper on chloride of benzoyl (Chiozza, Compt. rend, xxxvi. 631). 
 3. By the rapid dry distillation of a mixture of benzoate and formate of calcium : 
 
 C 7 H 5 Ca0 2 + CHCa0 2 -= C 7 H 6 + COW 
 
 a brown oily liquid passes over, whence hydride of benzoyl is separated by acid sul- 
 phite of ammonium (Piria, Ann. Ch. Pharm. c. 104). 4. By the action of nascent 
 hydrogen on cyanide of benzoyl. Cyanide of benzoyl is heated gently with hydro- 
 chloric acid and excess of zinc ; the cyanide turns yellow, and the zinc becomes covered 
 with an unctuous mass, containing hydride of benzoyl, hydrocyanic acid, and benzoin. 
 This, when heated with potash, yields reddish-yellow oily drops, which, when distilled, 
 yield pure hydride of benzoyl (Kolbe, Ann. Ch. Pharm. xcviii. 344). 5. By the ac- 
 tion of oxalate of silver on chloride of benzylene, 
 
 C 7 H 6 C1 2 + C 2 Ag 2 = C 7 H 6 + CO 2 + CO + 2AgCl. 
 
 The mixture must be very cautiously heated under rock-oil, otherwise a violent 
 reaction takes place, attended with complete destruction of the organic compound. 
 (Grolowkinsky, Ann. Ch. Pharm. cxi. 252.) 
 
 Crude bitter-almond oil contains, besides hydride of benzoyl, hydrocyanic and ben- 
 zoic acids, benzoin, and benzimide. By submitting the oil to fractional distillation, 
 hydrocyanic acid first passes over, and then tolerably pure hydride of benzoyl ; the 
 other compounds remain in the residxie. Pure hydride of benzoyl mav also be ob- 
 tained from the crude oil by several chemical means: 1. By agitating "the oil with 
 powdered mercuric oxide and water (v. Ittner), or with milk of lime and proto- 
 chloride of iron (W. and L.), and distilling. 2. By agitating the oil with three to four 
 
BENZOYL: HYDRIDE. 569 
 
 times its volume of acid sulphite of sodium of 27 B., or 1'231 specific gravity; dry- 
 ing by pressure, or on a porous tile, the crystalline mass which forms after some 
 hours ; washing it with cold alcohol ; dissolving it in the smallest possible quantity of 
 water, and decomposing it by a strong solution of sodic carbonate. The oil which 
 separates is decanted and distilled over chloride of calcium (Bertagnini, Ann. Ch. 
 Pharm. Ixxxv. 186). According to Miiller and Limpricht (Ann. Ch. Pharm. cxi. 
 136), it is necessary, in order to obtain a pure product by this method, either to re- 
 crystallise the crystalline compound before distilling it with carbonate of sodium, or 
 to rectify the liquid which passes over; the portion which distils up to 184 C. is then 
 free from hydrocyanic acid. 
 
 Pure hydride of benzoyl is a colourless, limpid, strongly-refracting liquid, with a 
 smell resembling that of oil of bitter-almonds, and a burning aromatic taste. Its 
 specific gravity is 1-0499 at 14'6 or 1-063 at C. (Kopp) ; boils at 179-1 with the 
 barometer at 751 '3 mm. ; vapour-density (calc.) 3'66. It is soluble in 30 pts. water, 
 and in all proportions in alcohol and ether ; when free from prussic acid, it is not 
 poisonous; in the animal organism it is converted into hippuric acid (Wohler and 
 Frierichs, Ann. Ch. Pharm. Ixvi. 336). It dissolves in sulphurous acid more easily 
 than in water, and separates out on evaporating the solution. It is generally regarded 
 as the aldehyde of the benzoic group, since it exhibits many of the reactions of an alde- 
 hyde, combining with acid sulphites of alkali-metals, and oxidising in moist air to 
 benzoic acid ; but it does not reduce silver-solutions. 
 
 It burns with a bright very smoky flame. It may be passed through a tube heated to 
 dull redness without decomposition ; but if the tube be filled with fragments of pumice- 
 stone, it is decomposed into benzoyl and carbonic oxide (Barreswil and Boudault, 
 J. Pharm. [3] v. 267). Heated to 100 C. in a sealed tube with ferric hydrate (pre- 
 viously dried at 100) it is oxidised, and yields a considerable quantity of ferrous ben- 
 zoate, part of the non-combined ferric oxide being also reduced to ferrous oxide 
 (G-rager, Ann. Ch. Pharm. cxi. 124). Dry chlorine converts it into chloride of ben- 
 zoyl and hydrochloric acid ; this decomposition is seldom complete, especially if the 
 gas be moist, a compound of chloride and hydride of benzoyl being formed (see below). 
 Bromine converts it into bromide of benzoyl and hydrobromic acid. Iodine does not 
 attack it. Cold strong nitric acid dissolves it undecomposed, and on heating, slowly 
 oxidises it into benzoic acid : fuming nitric acid, or nitrosulphuric acid, converts it into 
 hydride of nitrobenzoyl (see below). Strong sulphuric acid dissolves it, forming a 
 red solution, which blackens and gives off sulphurous anhydride when heated. With 
 sulphuric anhydride it forms a sulpho-conjugated acid, sulphomandelic acid (Mits- 
 cherlich, Lehrb. 4'" Aufl. i. 163). With perch! oride of phosphorus, it yields the chlo- 
 rides of benzylene and phosphoryl (C ah ours, Compt. rend. xxv. 725). Heated with 
 chloride of acetyl in equivalent proportions for several hours to 120 ISO C. in a sealed 
 tube, it yields hydrochloric and cinnamic acids (Bertagnini, Ann. Ch. Pharm. 
 c. 125): 
 
 C 7 H 6 + C 2 H 3 O.C1 = C 9 H 8 2 + HC1. 
 
 "With sulphydric acid or sulphide of ammonium, it yields peculiar products containing 
 sulphur, and varying according to the amount of alkali present, and the medium in 
 which the hydride of benzoyl is dissolved. In an alcoholic solution, it yields hydride 
 of thiobenzoyl (see below) ; in an ethereal solution, thiobcnzaldine. With ammonia 
 and sulphide of carbon it yields sulphocyanobenzylene. It dissolves potassium, becom- 
 ing thick and dark, but without evolution of hydrogen (Lowig). When heated with 
 solid potash, it evolves hydrogen, and is converted into benzoate ; with alcoholic potash, 
 into benzoate and benzylic alcohol. Cyanide of potassium converts it into benzoin. 
 With ammonia it forms various products (Laurent) ; with aqueous ammonia hydro- 
 benzamide and azobenzoilide; with alcoholic ammonia am ar in e, benzimic- 
 acid, and sometimes, dibenzoylimide (Robson). With aniline, it yields ben- 
 zylene-phenylamine ; with urea, benzoyluride. 
 
 Combinations. Benzoate of Hydride of Benzoyl. See BITTER- ALMOND OIL. 
 Hydride of Benzoyl with Chloride of Benzoyl. C 14 H U C10 2 = C 7 H 6 O.C 7 H 5 OC1 
 (Laurent and Gerhardt, Compt. chim. 1850, p. 123.) Formed abundantly when 
 hydride of benzoyl is imperfectly saturated with chlorine, or even when it is treated 
 with excess of chlorine. The saturated solution, when left to itself in a stoppered 
 bottle, gradually solidifies into a crystalline mass, which is washed with cold alcohol, 
 and dried. It forms colourless shining laminae, resembling benzoic acid ; melts very 
 readily, and remains liquid a long time when at rest ; heated above its melting point it 
 gives off chloride of benzoyl. When dry, it is inodorous, but if moist it gives off fumes 
 of hydrochloric acid, and smells of hydride of benzoyl. Hot. water decomposes it into 
 benzoic and hydrochloric acids, and hydride of benzoyl. It is insoluble in cold 
 alcohol ; warm alcohol decomposes it. It is decomposed by strong sulphuric acid. 
 
570 BENZOYL: HYDRIDE. 
 
 Hydrocyanate of Hydride of Benzoyl. C 8 H 7 NO = C 7 H B O.CNH (Voelckel 
 (1844), Pogg. Ann. bdi. 444). When crude bitter-almond oil or bitter-almond water 
 is mixed with hydrochloric acid, and evaporated below 100 C., till it is considerably 
 concentrated, this compound separates as a yellowish oil, which is washed with water, 
 and dried over sulphuric acid in vacuo. It is inodorous ; boils at 170 C. Specific 
 gravity T24. Slightly soluble in water, forming a bitter or neutral solution, readily 
 in alcohol or ether. It begins to decompose at 100 C., and when boiled is entirely 
 resolved into hydride of benzoyl and hydrocyanic acid ; it is similarly decomposed 
 by aqueous potash. When evaporated with strong hydrochloric acid, it takes up water 
 and forms mandelic acid and ammonia : 
 
 C 8 H 7 NO + 2H 2 = C 8 H 8 3 + NH 3 . 
 
 Gerhardt (Traite, iii. 193) mentions a compound obtained by distilling in a brine- 
 bath, a mixture of 2 pts. hydride of benzoyl, 1 pt. cyanide of mercury, and 1 pt. hy- 
 drochloric acid ; it is an oil which smells like hydride of benzoyl, has a specific gravity 
 of 1-10; is somewhat soluble in water, more in alcohol, readily in ether; does not solidify 
 at 12 C. ; boils at 312, yielding a distillate which crystallises on cooling. 
 
 Hydride of Benzoyl with Chloride of Calcium. When dry pulverised 
 chloride of calcium is added to anhydrous bitter-almond oil, heat is evolved, and a 
 solid compound is formed, which separates from the liquid in easily decomposible 
 crystals, apparently containing 2 -5 to 3*3 at. CaCl to 1 at. hydride of benzoyl. (Ek- 
 mann, Ann. Ch. Pharm. cxii. 151.) 
 
 Hydride of Benzoyl with Acid Sulphites of Alkali-metals. (Bertagnini, 
 Ann. Ch. Pharm. Ixxxv. 183.) 
 
 a. With Acid Sulphite of Ammonium. Hydride of benzoyl dissolves in all propor- 
 tions in acid sulphite of ammonium; but the resulting compound cannot be obtained in 
 the .crystalline state. The solution dissolves an excess of hydride of benzoyl, which 
 separates out on addition of water. Ammonia renders it turbid, and gradually preci- 
 pitates a body having the properties of hydrobenzamide. When the dry compound is 
 heated with excess of slaked lime, it yields amarine and lophire. (Grossmann.) 
 
 b. With Acid Sulphite of Potassium. When hydride of benzoyl is shaken up with a 
 solution of this salt of 28 30 Baume (specific gravity 1 '24 1-26), a crystalline magma 
 is speedily formed, which must be dried with filter-paper, and dissolved in dilute boiling 
 alcohol (if boiled too long decomposition takes place) ; the solution on cooling deposits 
 the compound in shining rectangular laminae. It is very soluble in water, less so in 
 presence of alkaline sulphites, not at all in a saturated solution of these salts ; spar- 
 ingly soluble in cold, readily in boiling, alcohol. It is permanent in the air. Its 
 aqueous solution is decomposed by boiling, either alone or with dilute acids, and by 
 alkaline carbonates, with separation of hydride of benzoyL 
 
 c. With Acid Sulphite of Sodium. C 7 H 6 O.S0 3 NaH. Aq. Formed like (b\ Small 
 white aggregated prisms, tasting of hydride of benzoyl and sulphurous acid, readily 
 soluble in water, sparingly in hot alcohol, insoluble in cold alcohol. It may be kept 
 in stoppered bottles, and decomposes but slowly when exposed to the air. When care- 
 fully heated in the air, it is decomposed without blackening, into sulphurous anhydride 
 and hydride of benzoyl, sulphite of sodium remaining ; in a stream of hydrogen, this 
 decomposition takes place below 100 C. Its aqueous solution is decomposed by boil- 
 ing, either alone or with acids or alkalis, like that of (&), also by iodine or chlorine, sodic 
 sulphate being formed. Nitric acid decomposes the dry salt in a similar manner. Its 
 aqueous solution gives, with barium-salts, a white precipitate, soluble in hydrochloric 
 acid ; it also precipitates lead- and silver-salts : the precipitates appear to contain a 
 portion of the oil. 
 
 Substitution-products of Hydride of Benzoyl. 
 
 Hydride of Nitrobenzoyl. Nitrobenzaldide. C 7 H 6 N0 3 = C 7 H 4 (NO) 2 O.H (Ber- 
 tagiiini, Ann. Ch. Pharm. Ixxix. 259 ; Ixxxvi. 190.) When hydride of benzoyl is gra- 
 dually added to fuming nitric acid, or to 15 20 vols. of a mixture of 1 vol. nitric and 
 2 vols. sulphuric acid, heat is evolved, and the addition of water precipitates hydride of 
 nitrobenzoyl in yellowish oily drops, which crystallise in a few days. The vessel must 
 be kept cool during the operation, otherwise nitrobenzoic acid will be formed. The 
 crystals are contaminated by a yellow fetid oil, whence they are purified by pressure be- 
 tween filter-paper, and recrystallisation from boiling dilute alcohol. 
 
 It forms white shining needles, inodorous when pure, with a taste like that of hy- 
 dride of benzoyl. It is slightly soluble in cold, readily in hot water or alcohol, less 
 so in ether ; dissolves undecomposed in nitric, hydrochloric, or sulphuric acids, and 
 crystallises out as the last solution absorbs moisture from the air. It melts easily to 
 a colourless liquid, which solidifies at 46 C. ; when further heated, it gives off vapours, 
 
BENZOYL: HYDRIDE. 571 
 
 which smell pleasantly when dilute, but are very pungent when concentrated. It may 
 be volatilised in small quantities without decomposition ; partly even when boiled with 
 water, completely when heated in an oil-bath in a stream of gas. 
 
 Hydride'of nitrobenzoyl burns with a smoky flame. It does not absorb oxygen from 
 the air, but is readily converted into nitrobenzoic acid by oxidising agents, e.g. 
 aqueous chromic acid, or a mixture of nitric and sulphuric acids. Chlorine in sunshine 
 converts it into chlorine of nitrobenzoyl (see BENZOYI,, CHLORIDE OF). Bromine dis- 
 solves readily in fused hydride of nitrobenzoyl, but does not decompose it till heated 
 over 100 C., when a brown resinous mass is formed. Strong hydrocyanic acid readily 
 dissolves it, the solution, if evaporated at once, deposits it unaltered, but after stand- 
 ing for a few hours, yields on evaporation, a viscid liquid, permanent in the air, soluble 
 in hot water, and separating out on cooling, which, when boiled with hydrochloric acid, 
 yields chloride of ammonium, and another body soluble in water. Cyanide of potas- 
 sium decomposes it at once, forming compounds which have not been examined. 
 With sulphydric acid, its alcoholic solution forms hydride of thionitrobenzylene 
 (see below). When its solution in alcoholic ammonia is treated with sulphuretted 
 hydrogen, a semifluid mass is deposited, which consists of a sulphur-compound mixed 
 with free sulphur; the former is dissolved out by ether, and obtained by evaporation as 
 a viscid reddish liquid, insoluble in water or dilute acids, soluble in warm alcohol ; it 
 is decomposed by heat, evolving sulphuretted hydrogen, and when boiled with nitric 
 acid, forms sulphuric acid and a yellow resin. Heated with sulphite of ammonium 
 it yields an acid product, readily soluble in water or alcohol. Alcoholic potash 
 converts it into nitrobenzoate in the cold ; aqueous potash requires the aid of heat. 
 Ammonia, whether dry, aqueous, or alcoholic, converts it into trinitrohydrobenzamide. 
 When it is gently heated with urea, water is given off, and the whole solidifies on cooling 
 into an opaque mass (nitrobenzoylureid?) slightly soluble in alcohol, readily in alcohol 
 containing hydrochloric acid, being thereby decomposed into urea and hydride of 
 nitrobenzoyl. 
 
 Hydride of nitrobenzoyl combines with acid sulphites of alkali-metals, forming com- 
 pounds of which the following have been examined : 
 
 a. With Acid Sulphite of Ammonium. C 7 H 5 NO 3 .S0 3 NH 5 + Aq. Hydride of 
 nitrobenzoyl is dissolved in a solution of acid sulphite of ammonium of 29 Bm. at a 
 gentle heat, when this compound crystallises out on cooling. It forms small, tran- 
 sparent, colourless prisms, which grate between the teeth, and have a bitter and sul- 
 
 Ehurous taste; are soluble in water or boiling alcohol, and crystallise readily from the 
 itter solution only. It is permanent in the air, though it gradually acquires a violet 
 tinge. Its aqueous solution is decomposed by boiling, either alone or with acids or 
 alkalis. With barium- lead- or silver-salts, its aqueous solution gives a precipitate of 
 metallic sulphite mixed with hydride of nitrobenzoyl ; with dichloride of platinum, it 
 gives chloroplatinate of ammonium. 
 
 b. With Acid Sulphite of Sodium. C 7 H 5 N0 5 .Sp 3 NaH + 5Aq. Obtained in the 
 same manner manner as (#), in yellow scales, which are rendered nearly colourless by 
 recrystallisation from a little hot water. It is readily soluble in hot, less so in cold 
 water : effloresces in the air : loses its water at 70 80 C. ; above 90 it is decomposed 
 giving off hydrogen, sulphurous anhydride, and hydride of nitrobenzoyl, sulphite of 
 sodium remaining behind. Its aqueous solution is decomposed by boiling, especially 
 on addition of acids or alkalis. 
 
 Hydride of Thiobenzoyl. Hydride of Sulphobcnzoyl. Sulphide of Stilbene. 
 Sulphopicramyl. C 7 H 6 S = C 7 H 5 S.H (Laurent, Ann. Ch. Phys. [3] i. 292. Koch- 
 leder, Ann. Ch. Pharm. xxxvii. 346. Cahours, Compt. rend. xxv. 357.) When 
 1 vol. of bitter- almond oil (crude or pure), is dissolved in 8 10 vols. alcohol, and 
 1 vol. sulphide of ammonium gradually added, this compound speedily separates as 
 a mealy powder, which is easily purified by washing with alcohol. It is also obtained 
 when an alcoholic solution of hydrobrobenzamide is supersaturated with sulphuretted 
 hydrogen, and the liquid left at rest. It is a white powder consisting of microscopic 
 granules; is inodorous, but imparts to the fingers a smell of onions; is insoluble in 
 water or alcohol. With ether it forms a transparent liquid, which resolidifies on adding 
 a few drops of alcohol. It becomes soft at 90 95 C. After fusion it solidifies to a 
 transparent non-crystalline mass. By dry distillation, it evolves sulphuretted hydrogen 
 and bisulphide of carbon, and yields a sublimate of stilbene and thionessal : 
 
 8C 7 HS = 2CS 2 + 3H 2 S + 2C 14 H 12 + C-' 6 H 18 S. 
 
 Stilbene. Thionessal. 
 
 It burns with an offensive smell and bright smoky flame. With bromine, it evolves 
 hydrobromic acid, and forms an oily body. Heated with nitric acid, it yields sulphuric 
 acid and hydride or hydrate of benzoyl ; with sulphuric acid, it dissolves, forming a 
 carmine solution, which water decolorises, precipitating yellow flakes; boiled \vitu 
 
572 BENZOYL : IODIDE BENZOYL-UREA. 
 
 hydrochloric acid, it evolves a little sulphuretted hydrogen. It is slowly decomposed 
 by alcoholic potash; water separates an oil from the solution, and acids evolve 
 sulphuretted hydrogen from the alkaline liquid. It is isomeric with sulphide of 
 benzylene. 
 
 Hydride of Thionitrobenzoyl. Sulphide of Nitrobenzylene. C 7 H 5 N0 2 S = 
 C 7 H 4 (N0 2 )S.H (Bertagnini, Ann. Ch. Pharm. Ixxix. 269). When an alcoholic 
 solution of hydride of nitrobenzoyl is saturated with sulphuretted hydrogen, this com- 
 pound separates as a grey light mealy powder, which is inodorous, but imparts a dis- 
 agreeable smell to the fingers. It becomes electric when rubbed. It does not dissolve 
 in the usual solvents, but melts in boiling water, aggregates together in boiling alco- 
 hol, and becomes soft and transparent with ether in the cold. It dissolves in strong 
 sulphuric acid, and is reprecipitated unaltered by water. Strong nitric acid decom- 
 poses it in the cold, dilute nitric acid on heating, forming sulphuric acid and hydride of 
 nitrobenzoyl. Alcoholic potash dissolves it in the cold, and water precipitates a 
 brown substance from the solution. Ammonia, whether dry or aqueous, attacks it, 
 evolving sulphuretted hydrogen, and forming (probably) trinitrohydrobenzamide. 
 
 Oxyiodide of Benzaldide. Cf'ITTO (Geuther and Cartmell, Ann. Ch. 
 Pharm. cxii. 1). This compound, which may be regarded as a triple molecule of 
 hydride of benzoyl (C 2I H 18 3 ), having 2 at. replaced by 4 at. I, is produced by the 
 action of hydriodic acid gas on hydride of benzoyl. Two layers of liquid are thereby 
 formed, the upper consisting of aqueous hydriodic acid ; the lower, which is oily, of the 
 oxyiodide : the latter may be purified by repeated treatment with water and acid sul- 
 phite of sodium. It is then obtained as a solid mass, which melts at 28 C. and 
 crystallises at 25 in colourless rhombic plates ; smells like cress ; dissolves readily in 
 alcohol and ether, and is insoluble in water. It may be distilled with water without 
 decomposition ; is not decomposed by acid sulphites of alkali-metals, but is resolved by 
 alcoholic potash into iodide of potassium, a small quantity of benzoic acid, and an 
 oily body soluble in alcohol, but different from bitter- almond oil. By ammonia, it 
 appears to be gradually converted into hydride of benzoyl. Boiled with nitrate of 
 silver, it forms iodide of silver, and emits an odour of bitter-almond oil. F. T. C. 
 
 BENZOYI., IODIDE OP. C 7 H 5 O.I. (Liebig and Wohler, Ann. Ch. 
 Pharm. iii. 266.) Obtained readily by heating iodide of potassium with chloride of 
 benzoyl ; a brown liquid distils over, which solidifies to a crystalline mass, coloured 
 brown by free iodine. When pure, it is colourless, lamino-crystalline and readily 
 fusible, always with partial decomposition; in solubility and general reactions it re- 
 sembles bromide of benzoyl. F. T. C. 
 
 BENZOYI,, PERCHLORIDE OF. See BENYOYL, CHLORIDE OF. 
 
 BEUZOYI., SULPHIDE OF. (C 7 H 5 O) 2 S (Liebig and Wohler, loc. cit.') 
 When chloride of benzoyl is distilled with finely-powdered sulphide of lead, a 
 yellow oil passes over, which solidifies to a soft yellow crystalline mass. It has an 
 unpleasant sulphurous smell ; is not decomposed by boiling with water or alcohol, and 
 but slowly with aqueous potash ; burns with a bright smoky flame, giving off siil- 
 phurous anhydride. F. T. C. 
 
 JBENTZOYI. SUX.PHOCYANXDE OF. See SlTLPHOCYANOBENZYLENE. 
 
 BEWZ01TI.AZOTXDE. C 15 N-H 12 (Laurent (1837), Ann. Ch. Phys. [2] Ixvi. 
 187. Laurent and Gerhardt, Compt. chim. (1850), 115. Kobson,Chem. Soc. Qu. 
 J. iv. 225). A product of the action of ammonia on bitter-almond oil. It is the 
 residue insoluble in alcohol, obtained in the preparation of azobenzoyl, benzhydramide, 
 and dibenzoylimide (q. v.) It is a white powder, without taste or smell, consisting of 
 microscopic prisms. It is insoluble in water; requires 300 400 pts. boiling a'cohol 
 for its solution, and at least as much ether. Fuses when heated, and solidifies to a 
 vitreous mass, in which a few oblique prisms separate. When boiled with alcohol and 
 hydrochloric acid, it is slowly decomposed, evolving hydrocyanic acid. By dry distil- 
 lation, it yields an oil, then a sublimate of lophine and amarone, and finally a 
 carbonaceous residue. 
 
 Gerhardt (Traite, iii. 194) describes this body and benzhydramide under the 
 name of hydrides of cyanazobenzoyl. 
 
 Quadrat (Ann. Ch. Pharm. Ixxi. 18), by heating sulphocyanobenzylene, obtained 
 a resinous mass, which, when exhausted with alcohol, left a crystalline residue, in- 
 soluble in water, almost so in alcohol, to which he assigns the formula C 15 H'N 2 . 
 The crystals are permanent at 100 C. and are not decomposed by nitric acid. 
 
 F. T. a 
 
 See BENZOIN. 
 
 BEVZOYXi-UREA. Syn. with BENzocABBAMiDE. See CAJBBAMIDB. 
 
BENZOYLURE1D BENZYL, HYDRIDE OF. 573 
 
 C M H w N 8 p 4 (Laurent and Gerhard!, Compt. chim. 
 [1850], p. 119). Formed by the action of urea on hydride of benzoyl : 
 4CH'N 2 + 3C 7 H0 = CH M N 8 4 -h 3H 2 0. 
 
 When 5 pts. powdered urea are heated to somewhat below 100 C. with 2 pts. hydride of 
 benzoyl, the mixture becomes liquid, and shortly solidifies to a compact mass. "When 
 cold, this is powdered, freed from excess of hydride of benzoyl by ether, and of urea by 
 boiling with water; the residue, which is dried at 120, is benzoylureid. It is a white 
 amorphous powder, without smell or taste, insoluble in water or ether, soluble in alcohol, 
 whence it separates on evaporation in amorphous crusts. It turns yellow at 170C. 
 gives off hydride of benzoyl a few degrees higher, and when further heated, yields 
 hydride of benzoyl and ammoniacal water, leaving a yellow residue, which finally 
 volatilises completely, and is sparingly soluble in alcohol. "When boiled with dilute 
 acids, it is decomposed into hydride of benzoyl and urea. It is not decomposed by 
 boiling ammonia ; slowly by strong boiling potash, evolving ammonia and hydride of 
 benzoyl, and leaving potassic benzoate in solution. Hydride of nitrobenzoyl yields 
 with urea a similar compound. (Bertagnini.) F. T. C. 
 
 BEHTZITREID. Syn. with BENZOYL-UREA. See CARBAMIDE. 
 
 BENZYL. Tolyl. Toluenyl. C 7 H 7 . A hypothetical radicle, isomeric with cresyL, 
 contained in benzylic alcohol, toluene, and other compounds. F. T. C. 
 
 BENZYL, CHLORIDE OP. Chloride of Tolyl or Toluenyl. Chlorotoluol. 
 C 7 H 7 C1 (Cannizzaro, Ann. Ch. Pharm. Ixvxviii. 129; xcvii. 246. Deville, Ann. 
 Ch. Phys. [3] iii. 178). Obtained by saturating benzylic alcohol with hydrochloric 
 acid gas whereupon heat is evolved, and the liquid divides itself into two layers, the lower 
 of which is aqueous hydrochloric acid, the upper chloride of benzyl. Or by passing chlo- 
 rine into hydride of benzyl in the dark, expelling excess of chlorine by a stream of 
 carbonic anhydride, and rectifying the product. It forms a colourless liquid, of specific 
 gravity 1-117 at C; boils at 170 (Deville) ; 175 176 (Cannizzaro); insoluble 
 in water, soluble in alcohol or ether. It is not attacked by aqueous potash ; alcoholic 
 potash decomposes it on boiling into benzylethylic ether and chloride of potassium. 
 When boiled with an alcoholic solution of acetate of potassium, it is converted into 
 acetate of benzyl ; of cyanide of potassium, into cyanide of benzyl. When heated 
 in a sealed tube with alcoholic ammonia, it yields tribenzylamine. F. T. C. 
 
 BENZYL CYAN-IDS OP. Cyanide of Tolyl or Toluenyl. C 8 H 7 N = C 7 H 7 .CN 
 (Cannizzaro, Ann. Ch. Phys. [3] xlv. 468). Obtained by boiling chloride of benzyl 
 with a strong alcoholic solution of cyanide of potassium, till no more chloride of 
 potassium separates out, and distilling the filtrate to remove the alcohol. The residual 
 liquid separates into two layers, the upper containing cyanide of benzyl, which may be 
 obtained from it by rectification? 1 It is a colourless liquid, which, by boiling with strong 
 potash, is converted into toluic acid, C 8 H 8 2 . F. T. C. 
 
 BENZYL, HYDRATE OP. Syn. with BENZYLIC ALCOHOL (q. v.) 
 
 BENZYL, HYDRIDE OP. Hydride of Tolyl or Toluenyl. Toluene or Toluol. 
 Benzoene. Dracyl. C 7 H 8 = C'H 7 .H. Discovered by Pelletier and Walter (1837) in 
 the oily products obtained in the manufacture of illuminating gas from resin ; first 
 examined by Deville. 
 
 Formed: 1. By the action of potash on benzylic alcohol (Cannizzaro, Ann. Ch. 
 Pharm. xc. 252 ; xcvi. 246) : 
 
 3C 7 H 8 + KHO = C 7 H 5 K0 2 + 2C 7 H 8 + 2H 2 O. 
 
 2. By heating toluic acid with excess of lime (No ad, ibid. Ixiii. 305) : 
 
 C 8 H 8 2 = C 7 H 8 + CO 2 . 
 
 3. By the djy distillation of tolu-balsam (Deville, Ann. Ch. Phys. [3] iii. 152, 168 ; 
 Muspratt and Hofmann, Ann. Ch. Pharm. liv. 9); of dragon's blood (Gle"nard 
 andBoudault, Ann. Ch. Phys. [3] iv. 274); of the resin of Pinus maritima (Pelle- 
 tier and Walter, ibid. [2] Ixvii. 269); of Burmese naphtha (De la Eue and 
 Miiller, Proc. Roy. Soc. viii. 221) ; of resin-oil (Couerbe, Ann. Ch. Phys. [2] Ixix. 
 184); of wood (Volckel, Ann. Ch. Pharm. Ixxxvi. 334), and of coal. In distilling 
 coal- tar, the portion which passes over at 100 115C. consists of toluene (Mansfield, 
 Chem. Soc. Qu. J. i. 266). 4. The yellow oil which separates from crude wood-spirit 
 on addition of water contains hydride of benzyl. (Cahours, Compt. rend. xxx. 319.) 
 
 Preparation. 1. When benzylic alcohol is distilled with four or five times its volume 
 of strong alcoholic potash in an apparatus which allows the less volatile products to 
 run back again, alcohol first passes over, then water, and finally, when the residue has 
 become solid, a mixture of hydride and hydrate of benzyl. This mixture is distilled 
 by itself, the portion which passes over at 116 C. collected apart and shaken up with 
 
574 BENZYL : HYDRIDE OF. 
 
 sulphuric acid, the decanted liquid washed with potassic carbonate, and twice rectified 
 over phosphoric anhydride. 2. When tolu-balsam, freed by distillation with water 
 from toluene, cinnamein, and a portion of the benzoic acid is subjected to dry distilla- 
 tion, there passes over, besides carbonic oxide and anhydride, water, abundance of 
 benzoic, and a little cinnamic acid, a heavy oil consisting of a mixture of benzoateof ethyl 
 (benzoate of methyl, according to Musprattand Scharling), and hydride of benzyl. 
 This oil is distilled, and the portion which passes over at 13 140 C. repeatedly rec- 
 tified over strong aqueous potash, and dried over chloride of calcium. E. Kopp 
 (Compt. chim. 1849, p. 149) purifies the balsam by boiling with sodic carbonate, boils 
 the residue with strong aqueous soda, distils the brown solution, decants the oil which 
 passes over from the water which accompanies it, and rectifies it repeatedly. 3. To 
 prepare hydride of benzyl from coal-tar, the oil which comes over at 100 120 C. is 
 mixed with half its weight of sulphuric acid and rectified, when a product of constant 
 boiling-point is obtained. (Wilson, Chem. Soc. Qu. J. iii. 154.) 
 
 Hydride of benzyl is a colourless, very mobile, strongly refracting liquid, with a 
 smell like benzene, and a burning taste; specific gravity 0-87 at 18 C. (Deville). 
 The boiling-point is variously stated at from 103 0> 7 (Church), to 114 (Gerhardt), 
 vapour-density 3'27 (Deville); does not solidify at 20. It is insoluble in water, 
 slightly soluble in alcohol, more so in ether or in fixed or volatile oils. It dissolves 
 most resins, also iodine, forming an amber-red solution, and, when heated, sulphur, 
 which crystallises out on cooling. 
 
 It is not decomposed when passed through a red-hot tube filled with potash-lime. 
 It burns with a smoky flame. With chlorine, it evolves heat, and yields several sub- 
 stitution-compounds (see below). With fuming nitric acid, it yields substitution-com- 
 pounds (see below). It dissolves in fuming sulphuric acid, forming sulphibenzylic 
 (sulphotoluic) acid, and sulphibenzyl (sulphotoluol). It is not attacked either by 
 potassium or by potash. When digested with sodium, in a closed vessel for fourteen 
 days, it yields two substances, boiling respectively at 97 C. and 112. (Church, 
 Phil. Mag. [4] ix. 256.) 
 
 Substitution-products of Hydride of Benzyl. 
 
 Deville (Ann. Ch. Phys. [3] iii. 178) enumerates several compounds obtained by 
 the action of chlorine on hydride of benzyl. When the reaction takes place in the 
 dark, chloride of benzyl (chlorotoluol) is the product (see BENZYL, CHLORIDE OF). 
 When chlorine is passed through hydride of benzil in bright daylight, as long as hy- 
 drochloric acid is evolved, and excess of chlorine removed by carbonic anhydride, 
 hydrochlorate of trichlorotoluol, C 7 H 4 C1 6 = C 7 H 5 C1 3 .HC1, is formed ; when distilled it 
 decomposes and evolves hydrochloric acid. When the action of the gas is still further 
 prolonged, a thickish liquid is formed, together with some crystals. If the liquid be sepa- 
 rated, further treated with chlorine with aid of heat, and purified by carbonic anhy- 
 dride, the product is dihydrochlorate of pentachlorotoluol, C 7 H 5 C1 7 = C 7 H 3 C1 5 .2HC1 ; 
 when distilled it evolves hydrochloric acid ; it is soluble in ether. The crystals are tri- 
 hydrochlorate of pentachlorotoluol, C 7 H 6 C1 8 = C 7 H 3 C1 5 .3HC1, they are purified by recrys- 
 tallisation from ether, in which they are soluble, especially with aid of heat ; they are 
 colourless when pure. When the liquid and crystals together are distilled in a stream 
 of chlorine, the distillate being repeatedly poured back again, the whole is gradually 
 converted into a silky substance, abundance of hydrochloric acid being evolved ; this 
 substance, which is hexchlorotoluol (hydride of hexchlorobenzyl), C 7 H 2 C1 6 , is purified 
 by pressure between filter-paper and recrystallisation from ether ; it is volatile without 
 decomposition. 
 
 Hydride of Nitrobenzyl. Nitrotoluol C 7 H 7 N0 2 = C 7 HNO 2 .B:. (Deville, /oc. 
 cit. ; G16nard and Boudault, Compt. rend. xix. 505; Hofmann and Muspratt, 
 Ann. Ch. Pharm. liii. 220, 224.) Hydride of benzyl is added to cold fuming nitric acid 
 as long as it dissolves immediately ; on adding water to the red solution, hydride of 
 nitrobenzyl separates as a red liquid, which may be decolorised by washing with 
 water and repeated distillation. It is a nearly colourless liquid, smelling of bitter 
 almonds, with a very sweet and afterwards pungent taste; specific gravity 1*18 at 
 16-5 C. ; vapour-density 4-95 ; boils at 225 230 C. Eeadily soluble in alcohol or 
 ether. It is partially decomposed by distillation, completely when passed at a high tem- 
 perature through a red-hot tube filled with pieces of glass. It burns with a smoky 
 flame, emitting the odour of gum-benzoin ; when passed over red-hot baryta, it is re- 
 solved into phenylamine and carbonic anhydride. With fuming sulphuric acid it forms 
 nitrosulphotoluic acid (Church). Aqueous potash dissolves it, forming a red solution, 
 whence hydrochloric acid precipitates a brown powder ; with alcoholic potash it forms 
 a black liquid, whence a reddish oil containing phenylamine is obtained by distillation. 
 Boiled with alcoholic sulphite of ammonium, it forms thiotoluate of ammonium. 
 With sulphide of ammonium, it yields benzylamine. 
 
BENZYLAMINE. 575 
 
 Hydride of Dinitrobenzyl. Dinitrotoluol. C 7 H 6 N 2 4 = C 7 H 5 (N0 2 ). 2 H. (De- 
 ville, loc. tit. ; Cahours, Compt. rend. xxiv. 555.) Obtained by boiling hydride of 
 benzyl with fuming nitric acid, or treating it with nitrosulphuric acid. It crystallises 
 from alcohol in lustrous, hard, brittle, prismatic needles, which melt at 7lC. and 
 solidify to a radiated mass. It boils at 300, becoming coloured, and leaving a resi- 
 due : when strongly heated, it yields a sublimate. It is sparingly soluble in water. 
 It is not attacked by fuming nitric acid. Its solution in potash deposits a brown 
 powder on addition of hydrochloric acid. Sulphide of ammonium converts it into 
 nitrobenzylamine. F. T. C. 
 
 BENZYL. IODIDE OF. C 7 H 7 I. (Cannizzaro, 1854.) When a solution of 
 benzylic alcohol in bisulphide of carbon is mixed with a solution of phosphorus in bi- 
 sulphide of carbon, iodine gradually added, and excess of bisulphide distilled off, 
 a liquid is obtained, which irritates the eyes, and is probably iodide of benzyl. 
 
 F. T. C. 
 
 BENZYI.AIttZNE. Toluidine. C 7 H 9 N = N.C 7 H 7 .H 2 . (Muspratt and Hof- 
 mann (1845), Ann. Ch. Pharm. liv. 1 ; No ad, ibid. Ixiii. 305; Hofmann, ibid. Ixvi. 
 144; Wilson, Chem. Soc. Qu. J. iii. 154; Chautard, J. Pharm. [3] xxiv. 166.) 
 Formed by the reduction of hydride of nitrobenzyl by sulphydric acid (Mus- 
 pratt and Hofmann) : or by the action of potash on the yellow resin obtained by 
 treating oil of turpentine by nitric acid. (Chautard.) 
 
 Preparation. 1. A solution of hydride of nitrobenzyl in alcohol saturated with 
 ammonia, is treated with sulphuretted hydrogen till it smells strongly of the gas, even 
 after long standing : sulphur then crystallises out. The reaction is accelerated by the 
 application of heat, but the decomposition is never complete. The product is mixed 
 with water and hydrochloric acid, and shaken up with ether to remove undecomposed 
 hydride ; it is then evaporated to |, and distilled with potash, when water, ammonia, 
 and benzylamine pass over, the last as a heavy oil, which soon crystallises. The 
 whole distillate is saturated with oxalic acid, evaporated to dryness on the water-bath, 
 and exhausted with boiling absolute alcohol, which dissolves only the oxalate of benzyl- 
 amine, which crystallises on cooling. The crystals are washed, dissolved in boiling 
 water, and the solution decomposed by strong potash, when benzylamine separates in 
 oily drops, which collect and crystallise into a radiated mass on cooling : it is purified 
 by washing and one rectification, or by crystallisation from ether. 2. The resin ob- 
 tained by treating oil of turpentine with nitric acid, is gradually mixed with aqueous 
 potash; the mixture assumes a dark-brown colour, and becomes hot, and when the 
 reaction has ceased, it is distilled as long as alkaline vapours pass over. The dis- 
 tillate is supersaturated with hydrochloric acid, evaporated to dryness over the water- 
 bath, and exhausted with absolute alcobol, which dissolves hydrochlorate of benzyl- 
 amine, and leaves sal-ammoniac undissolved. 
 
 Benzylamine crystallises from dilute alcohol in large colourless laminae, which are 
 sparingly soluble in cold, more readily in boiling, water : readily in alcohol, ether, 
 wood-spirit, acetone, fixed and volatile oils, and bisulphide of carbon. It smells like 
 phenylamine, and has a burning taste. It evaporates at ordinary temperatures, melts 
 at 40 C. to a colourless, strongly-refracting oil, and boils at 198. It is heavier than 
 water ; slightly blues red litmus, but does not redden turmeric ; colours fir-wood deep 
 yellow, but does not give the purple colour of phenylamine with chloride of lime, but 
 only a faint reddish tint. With nitric acid benzylamine gives a deep-red, phenyla- 
 mine a deep-blue, colour. 
 
 Bromine acts on benzylamine violently : when the product is heated, shining needles 
 sublime, insoluble in water, soluble in alcohol and ether, probably tribromobenzyla- 
 mine. It is decomposed by boiling with strong nitric acid, with evolution of nitrous 
 fumes ; water added to the solution precipitates yellow flakes, which dissolve in 
 alkalis, and are reprecipitated by acids. With aqueous chromic acid, it gives a red- 
 brown precipitate. When its vapour is passed over fused potassium, vivid combus- 
 tion takes place, and potassic cyanide is formed. Cyanogen passed into its alcoholic 
 solution, yields cyanobenzylamine (see below). With chloride of cyanogen it 
 forms melobenzylamine (metoluidine) (see below.) With bromide or iodide of 
 ethyl, it yields benzylethylamine (see below). 
 
 Combinations. 1. With ACIDS. Benzylamine combines with acids, forming crys- 
 talline salts, which are mostly inodorous and colourless, but quickly become rose- 
 coloured when exposed to the air : they are decomposed by alkalis or alkaline carbonates, 
 benzylamine being separated as a crystalline curd. The chloraurate, AuCl 4 C 7 H 10 N, 
 separates as a thick precipitate, which soon aggregates to a crystalline mass, when the 
 hydrochlorate is mixed with trichloride of gold : it melts* in water at 50 60C., dis- 
 solves when further heated, and crystallises on cooling in fine yellow needles. The 
 chloroplatinate, PtCl s C 7 H 10 N, separates as an orange-yellow crystalline pulp, when the 
 
576 BENZYLAMINE. 
 
 hydrochlorate is mixed with bichloride of platinum : it is washed with ether-alcohol 
 and dried in a water-bath. The chloropalladate is similar in appearance. The hydro- 
 chlorate, C 7 H 10 NC1, is deposited in white crystalline scales, becoming yellow on 
 exposure to the air, when a solution of benzylamine in hydrochloric acid is evaporated 
 and cooled: it is readily soluble in water or alcohol, sparingly in ether, forming acid 
 solutions : when gently heated, it sublimes like sal-ammoniac. The nitrate, phosphate, 
 and sulphite are crystallisable. The acid oxalate, C 2 4 .C 7 H 10 KH + Aq, is obtained 
 by mixing an alcoholic solution of benzylamine with excess of oxalic acid, in delicate 
 silky needles, soluble in boiling water or alcohol, insoluble in ether. The sulphate, 
 S0 4 (C 7 H IO N) 2 , is obtained when a few drops of sulphuric acid are added to an ethereal 
 solution of benzylamine, as a white crystalline precipitate, which may be washed with 
 ether : it is readily soluble in water, sparingly in alcohol. With cupric sulphate or 
 chloride, benzylamine gives a greenish crystalline precipitate ; with nitrate of silver, 
 a white precipitate, which soon blackens; it precipitates ferric hydrate from ferric 
 chloride. 
 
 2. With CYANOGEN; Cyanobenzylamine; Cyanotoluidine. C 8 H 9 N 2 = C 7 H 9 N.CN. 
 (Hofmann, loc. cit. Chem. Soc. Qu. J. i. 170.) When cyanogen is passed through an 
 alcoholic solution of benzylamine, the red-brown solution deposits, after some hours, a 
 crystalline mass, whence hydrochloric acid extracts cyanobenzylamine, which is pre- 
 cipitated by potash from the hydrochloric acid solution. It is homologous with 
 cyanophenylamine, which it closely resembles, only being less soluble in alcohol or 
 ether. 
 
 Melobenzylamine. Metoluidine. C 15 H 17 N 3 = C 7 H 9 N.C 7 H 8 CyN. (Wilson, foe. 
 cit.) When the vapour of chloride of cyanogen is passed over fused benzylamine, 
 heat is evolved, and a resinous mass obtained, consisting of hydrochlorate of metolui- 
 dine ; this is dissolved in water acidulated with hydrochloric acid, filtered, and mixed 
 with potash; and the white precipitate thus produced, is boiled with potash, washed, and 
 recrystallised from alcohol. Crystalline laminae, sparingly soluble in cold, somewhat 
 more in boiling water ; crystallises best from a mixture of water and alcohol ; readily 
 soluble in hydrochloric acid : the solution gives with dichloride of platinum, a dark- 
 yellow precipitate of chloroplatinate, which is insoluble in water or alcohol and may 
 be dried at 100 C. It is homologous with melaniline (melophenylamine). 
 
 Secondary and Tertiary Amines containing Benzyl. 
 
 Benzylethylamine. Ethyltoluidine. C 9 H 13 N - N.C 7 H 7 .C 2 H 5 .H. (Morley and 
 Ab el, Chem. Soc. Qu. J. vii. 68.) Benzylamine is heated with iodide of ethyl in a sealed 
 tube for two or three days in a water-bath ; the product freed from excess of iodide by 
 heat ; the resulting oil, which is hydriodate of benzylethylamine, distilled with strong 
 potash, and the distillate rectified over solid potash. It is a colourless oil with a peculiar 
 smell : specific gravity 0-9391 at 15-5 C. ; boils at 217 The chloroplatinate is a pale- 
 yellow crystalline compound, soluble in water or alcohol, less so in ether : at 100 it 
 becomes dark, and is decomposed. The oxalate and sulphate are crystalline. 
 
 Benzyldiethylamine. Diethyltoluidine. C"H 17 N = N.C 7 H 7 .(C 2 H 5 ) 2 . Prepared 
 in the same manner as the foregoing compound, benzylethylamine being substituted for 
 benzylamine. A colourless, odorous oil : specific gravity 0-9242 at 15'5 C., boils at 229. 
 The chloroplatinate is a resinous non-crystalline mass. The hydriodate forms oily drops 
 which crystallise when touched with a glass-rod ; is very soluble in water, decomposes 
 when exposed to the air, or in contact with alcohol. 
 
 Benzyltriethylium. C 13 H 22 N = N.C 7 H 7 .(C 2 H 5 ) 3 . Known only in combination 
 with acids. When benzyldiethylamine is heated with iodide of ethyl to 100 C. in a 
 sealed tube till crystals are formed and excess of iodide of ethyl is removed by dis- 
 tillation, iodide of benzyltriethylium remains as a heavy oil. This is decomposed 
 by heating with oxide of silver, yielding a solution of hydrate of benzyltriethylium 
 N.C 7 H 7 (C 8 H 5 ) 3 .H.O, which is strongly alkaline, has a bitter taste, and precipitates 
 most metallic salts. The chloroplatinate is insoluble in cold, soluble in hot water, 
 whence it crystallises in fine needles ; it loses platinum on recrystallisation. 
 
 Nitrobenzylamine. Nitrotoluidine. C 7 H 8 N 2 2 = KC 7 H 6 N0 2 .H 2 . (Cahours. 
 Compt. rend. xxx. 320.) Formed by the action of sulphide of ammonium on hydride 
 of dinitrobenzene ; it crystallises in yellow needles, forms definite compounds with 
 nitric, hydrochloric, sulphuric, and phosphoric acids : yields alkalamides with the 
 chlorides of benzene and cumyl. 
 
 Tribenzylamine. C 21 H 21 N = N.(C 7 H 7 ) 3 . (Cannizzaro, Cimento, iii. 397.) 
 When chloride of benzyl is heated with alcoholic ammonia to 100 C. in a sealed tube, 
 ammonia passed into the cooled product, the resulting precipitate exhausted with 
 ether, and the ethereal solution evaporated, this compound is obtained in shining 
 laminae, which melt at 91 -3 C. to a colourless liquid, and at 360 volatilise with 
 
BENZYLENE. 577 
 
 partial decomposition. It is sparingly soluble in cold water or alcohol, more so in boil- 
 ing alcohol, still more in ether, forming alkaline solutions. The hydrochlorate crystal- 
 lises in needles from hot water. The chloroplatinate forms orange-needles. F. T. C. 
 
 BESMZYLEPOTE. C 7 H 6 . A hypothetical diatomic radicle, of which, according to 
 Wicke (Ann. Ch. Pharm. cii. 356.) Cahours' chlorobenzol is the chloride. It has 
 not been isolated ; neither has its hydrate (benzylenic or benzolic alcohol,) C 7 H 6 .H 2 .0 2 , 
 nor its oxide (benzyleuic ether) C 7 H 6 been obtained ; the reason assigned by Wicke 
 being that the former readily decomposes, yielding water and the latter compound, 
 which in turn is readily converted into its isomer, hydride of benzoyl. Several com- 
 pound ethers have, however, been obtained, representing the alcohol in which the 
 2 atoms of basic hydrogen are replaced by positive or negative organic radicles (see 
 BENZYJLENIC ETHERS). Hydrobenzamide C 21 H 18 N 2 , should probably be regarded as a 
 tertiary diamine containing this radicle. N 2 (C 7 H 6 ) 8 . F. T. C. 
 
 CHLORIDE OP. Chlorobenzol. C 7 H 6 C1 2 . (Cahours (1848), 
 
 Ann. Ch. Phys. [3] xxiii. 129. Wicke, Ann. Ch. Pharm. cii. 356.) When hydride of 
 benzoyl is brought into contact with a slight excess of pentachloride of phosphorus, a 
 lively action takes place; and if, when this is over, a gentle heat be applied, oxychloride 
 of phosphorus distils over at about 110 C., and chloride of benzylene at about 206. 
 The latter is washed with water, dried over chloride of calcium, and rectified. It is a 
 colourless liquid, smelling faintly in the cold, but strongly when heated ; insoluble in 
 water, soluble in alcohol or ether : specific gravity 1-245 at 16 : vapour- density 
 (expt.) 5-595 ; boils at 206 208. It is not oxidised by exposure to the air, or to 
 oxygen. When heated in a water-bath with alcoholic potash, more slowly with 
 aqueous potash to 100, in a sealed tube, it yields chloride of potassium and hydride 
 of benzoyl. Ammonia, whether dry, aqueous, or alcoholic, does not act upon it in the 
 cold: when heated in a sealed tube to 100 with an ammonia-solution, it yields 
 chloride of ammonium, and bitter-almond oil. It is not attacked by dry cyanide of 
 'potassium at 100. Heated with alcoholic sulphocyanate of potassium to 100 in a 
 sealed tube, it yields chloride of potassium, and an oil smelling like oil of mustard. 
 Alcoholic nitrate of silver deprives it of all its chlorine, hydride of benzoyl being formed. 
 Alcoholic hydrosulphate of potassium converts it into sulphide of benzylene. 
 
 Gerhardt (Trait6, iii. 167) regards this compound as hydride of benzoyl in which 
 oxygen is replaced by chlorine : Wicke, however, shows conclusively that it possesses 
 none of the properties of an aldehyde. F. T. C. 
 
 BENZYX.ENE, SULPHIDE OP. Sulphobenzol, C 7 H 6 S. (Cahours, loc. cit.) 
 
 Formed by the action of alcoholic sulphydrate of potassium on chloride of benzylene, 
 and recrystallised from boiling alcohol, in which it is readily soluble. White pearly 
 scales, insoluble in water, which melt at 64 C. and crystallise on cooling : when further 
 heated, it is partly volatilised, and partly decomposed. It is oxidised even by dilute 
 nitric acid, with formation of sulphuric acid, and a substance soluble in alkalis, which 
 crystallises in shining yellow scales, F. T. C. 
 
 BENZYLENE-PHENYI,.ft.lVErN-E. Benzosylanilide. Stilbylanilinc. C 13 H U N = 
 N.C 7 H 6 .C G H 5 . (Laurent and G-erhardt, Compt. chim. 1850, 117.) When perfectly 
 dry hydride of benzoyl is mixed with about its own volume of perfectly dry phenyl- 
 amine, water separates out, and a crystalline mass forms after a time (sometimes not 
 until water is added) : this is pressed between filter-paper, and recrystallised from hot 
 alcohol, or purified by rectification. It forms beautiful shining laminse, without taste 
 or smell, insoluble in water, soluble in alcohol or ether. It is easily fusible, and boils 
 at a very high temperature without decomposition. Bromine acts with violence on its 
 alcoholic solution, forming after a time crystals of tribromophenylamine. With cold 
 fuming nitric acid, it forms a dark-green solution, whence water precipitates hydride 
 of benzoyl, nitrate of phenylamine remaining in solution : sulphuric acid decomposes 
 it in a similar manner, forming a yellow solution. It becomes liquid by contact 'with 
 acetic or hydrochloric acid : the latter dissolves it on boiling, without decomposition. 
 It is scarcely attacked by boiling potash. F. T. C. 
 
 BEXTZYXiEN'XC ETHERS. Salts or ethers of Benzylene. (Wicke, loc. tit.) 
 a. Ethers containing a Positive Radicle. 
 
 METHYLBENZYLENIC ETHER. Methylate of Benzylene. C 9 H 12 2 = C 7 H 6 .(CH 3 ) 2 2 . 
 
 A mixture of 1 at. chloride of benzylene with a solution of 2 at. sodium in abso- 
 lute metbylic alcohol, is heated for some hours, when chloride of sodium separates in 
 abundance ; the methylic alcohol is distilled off, and the residue mixed with water, 
 when the ether rises to the surface, and is removed with a pipette, dried and rectified. 
 It is a transparent, colourless liquid, heavier than water, with a pleasant smell like 
 that of geraniums ; insoluble in water, soluble in wood-spirit, alcohol, or ether. It 
 boils at 208 C,, leaving a brown residue arising from decomposition 
 
 VOL. I. P P 
 
578 BENZYLENIC ETHEES EENZYLIC ALCOHOL. 
 
 ETHYIJJENZYLENIC ETHER. Ethylate of Benzylene. C n H 16 2 = C 7 H 6 (C 2 H 5 ) 2 .0-. 
 Prepared precisely like the foregoing compound, ethylic being substituted for methylic 
 alcohol. It boils at 222 C. : in other respects it resembles the methyl-compound. 
 
 AMYLBENZYLENIC ETHER. Amylate of Benzylene. C 17 H 28 2 = C 7 H 6 .(C 5 H n ) 2 .0 2 . 
 Prepared like the preceding compounds : but the ether must be separated by fractional 
 distillation, not by addition of water. It is a slightly yellowish oil, smelling like fusel- 
 oil, and lighter than water : it boils, not without considerable decomposition, about 
 292 C. 
 
 b. Ethers containing Acid Radicles: 
 
 The only one of these which has been obtained perfectly pure, and in the crystalline 
 form, is 
 
 ACETOBENZYLENIC ETHER. Acetate of Benzylene. C"H 12 4 = C 7 H 6 .(C 2 H 3 0) 2 .0 2 
 1 at. chloride of benzylene is triturated with rather more than 2 at. dry acetate of 
 silver, and the mixture heated very gently in a flask ; the reaction is so violent that 
 it is well not to use more than 10 grm. silver-salt at a time. The product, when cool, 
 is repeatedly extracted with ether ; the extracts are distilled in the water-bath ; and 
 the yellowish oily residue is washed with weak soda-solution and with water, then 
 redissolved in ether, and left to evaporate. A viscid oil is thus obtained, in which 
 crystals gradually form, until at last it solidifies completely. It forms small white shining 
 crystals, belonging to the monoclinic system, insoluble in water, soluble in alcohol or 
 ether, whence it separates on evaporation as an oil, which often does not crystallise till 
 agitated. It melts at 36 C., and crystallises on cooling : begins to boil at 190, the 
 temperature gradually rising to 240 , and yields a distillate consisting of acetic an- 
 hydride and hydride of benzoyl. Heated with aqueous potash or dilute sulphuric 
 acid, to 100 in a sealed tube, it is converted into acetic acid and hydride of benzoyl: 
 with aqueous ammonia under the same circumstances, it yields acetamide and hydro- 
 benzamide. 
 
 BENZOBENZYLENIC ETHER. Benzoate of Benzylene. C 21 H 16 4 = C 7 H 6 .(C 7 H 5 0) 2 .0 2 . 
 Chloride of benzylene acts violently on benzoate of silver, with evolution of heat : the 
 ethereal extract of the product yields on evaporation a viscid, brown, non-crystallisable 
 mass. With alcoholic potash it forms immediately a solid mass of potassic benzoate, 
 mixed with hydride of benzoyl. 
 
 StJcciNOBENZYLENic ETHER. Succinate of Benzylene. C U H 10 4 = C 7 H G .C 4 H 4 2 ,0 ? . 
 
 Prepared like the foregoing compounds : its ethereal solution is decomposed by 
 evaporation or by washing with dilute soda, into succinic acid and hydride of benzoyl. 
 
 SULPHOBENZYLENIC ETHER. Sulphate of Benzylene. C 7 H 6 S0 4 = C 7 H e S0 2 .0 2 . Pre- 
 pared in the same manner. It is a red-brown, non-crystallisable oil. 
 
 VAXEROBENZYLENIC ETHER. Valerate of Benzylene. C I7 H 24 4 = C 7 H 6 .(C 5 H 9 0). 2 0. 
 
 Obtained like the acetate. On evaporating its ethereal solution, it remains as a thick, 
 yellow, non-crystallisable oil, which is decomposed by distillation into valerianic acid 
 and hydride of benzoyl. 
 
 Chloride of benzylene acts so violently on oxalate of silver, that no definite product 
 can be obtained. ' F. T. C. 
 
 BEOTZY3,:DZETHYI.AIrWE. BENZYX.- 
 
 TRIETHYIiIUlVT. (See BENZYLAMINE.) 
 
 BENZYX.XC AXiCOHOXi. Hydrate of Benzyl. Benzole Alcohol. Toluylic 
 Alcohol. C 7 H 8 = C 7 H 7 .H.O. (Cannizzaro [1853], Ann. Ch. Pharrn. Ixxxviii. 129 ;'xc. 
 252; xcii. 113; xcvi. 246; Scharling, ibid, xcvii. 168.) Formed: 1. By the action 
 of alcoholic potash on hydride of benzoyl : 
 
 2C 7 H 6 + KHO = C 7 H 8 + C 7 H 5 K0 2 . 
 
 When a mixture of pure hydride of benzoyl with its own volume of absolute alcohol is 
 mixed with 3 4 vols. alcoholic potash, of specific gravity 1'02, heat is evolved, and the 
 whole solidifies to a crystalline magma. The potassic benzoate is dissolved out with 
 hot water, the alcohol distilled off, the residue mixed with water till it begins to be 
 turbid, and then shaken up with ether. The brown oily residue obtained by eva- 
 
 nting the ethereal solution, is dried over fused potash, and repeatedly rectified. 
 \Then acetate of benzyl, obtained by boiling chloride of benzyl with alcoholic ace- 
 tate of potassium, is boiled with strong alcoholic potash, and the alcohol distilled off, 
 the residual liquid separates into two layers, the upper of which contains benzyl ic 
 alcohol, which is separated by fractional distillation. 3. Scharling has shown that 
 the substance known as pcruvin, obtained by the action of potash on cinnamcin, is 
 benzylic alcohol. 
 
 It is a colourless, strongly-refracting oil, with a faint pleasant smell : specific gravity 
 1-051 at 14-4 C., 1-063 at D (Kopp) : vapour- density (expt.) 3'85 : boils at 206'5, 
 
BENZYLIC ETHER- BERBERINE. 579 
 
 under pressure of 75T4 mm. (Kopp.) It is insoluble in water: soluble in all pro- 
 portions in alcohol, ether, acetic acid, or bisulphide of carbon. 
 
 When its vapour is passed through a red-hot tube filled with spongy platinum, ben- 
 zene with other compounds is formed. It is converted into hydride of benzoyl by 
 oxygen, in presence of platinum- black, or by nitric acid : aqueous chromic acid converts 
 it into benzoic acid. With strong sulphuric acid, phosphoric anhydride, or chloride of 
 zinc, it yields a brown resin, insoluble in water, alcohol, or ether (probably stilbene). 
 Fused boric anhydride converts it at 100 120 C. into benzylic ether, at a higher 
 temperature into stilbene (or benzylene ?) : with fluoride of boron, it yields the same 
 product. Distilled with strong alcoholic potash, it yields hydride of benzyl (q. v.} 
 
 F. T. C. 
 
 BEKTZYXXC EITHER C 14 H 14 = (C 7 H 7 ) 2 .0. (Cannizzaro, Ann. Ch. Pharm. 
 xcii. 115.) Fused and pulverised boric anhydride is mixed into a paste with benzylic 
 alcohol ; the mixture is heated for some hours to 120 125 C. ; and the resulting hard 
 brown mass is treated with water and a solution of alkaline carbonate, when a greenish- 
 brown oil rises to the surface. When this is distilled, benzylic alcohol passes over below 
 300, and benzylic ether at 300 315 : the residue contains stilbene. Benzylic ether 
 is a colourless, slightly fluorescent oil, boiling at 300 315. When heated above its 
 boiling-point, it becomes yellow and is decomposed, yielding resinous stilbene, hydride 
 of benzoyl, and a light oil, which is probably hydride of benzyl. With phosphoric 
 anhydride or sulphuric acid, it yields the same product as benzylic alcohol. 
 
 Ethyl-benzylic Ether. C 9 H 12 = C 7 H 7 .C 2 H 5 .0. (Cannizzaro, Cimento, iii. 397.) 
 Chloride of benzyl is distilled upwards with alcoholic potash, and the resulting liquid is 
 decanted from the chloride of potassium, and mixed with water, when it separates into 
 two layers : the upper of these is distilled, and the portion which comes over at 185 C. 
 dried over chloride of calcium and rectified. Colourless, mobile liquid, with a pleasant 
 smell; lighter than, and insoluble in, water: boils at 185. 
 
 For the compound benzylic ethers containing acid radicles, see ACETIC and BENZOIC 
 ACIDS. F. T. C. 
 
 BEXt A UNITE, A hydrated sesquiphosphate of iron occurring at St. Benigna in the 
 circle of Beraun in Bohemia, together with cacoxene and Dufrenite. It forms ra- 
 diated or laminar masses, with perfect cleavage in one direction ; imperfect at right 
 angles to the first. Specific gravity 2-878. Hardness 2'0 to 2*5. Kather brittle. 
 
 BERBERXSTE. C 21 H 19 N0 5 (?)* 4 n organic base discovered in 1837, by 
 Buchner (Ann. Ch. Pharm. xxiv. 228), in the root of the barberry (Berberis mdgaris}, 
 and since found in other species of Berberis growing in Mexico and in India. It has 
 also been obtained by Bodeker (Ann. Ch. Pharm. Ixvi. 384 ; Ixix. 40), from Colombo- 
 root (Cocculus palmatus) ; by Perrins (Ann. Ch. Pharm. Ixxxiii. 276), from the 
 colorabo-root of Ceylon ( Menispermum fenestratum} ; and by Stenhouse (Pharm. 
 J. Trans, xiv. 455), in a yellow bark used as a dye by the natives of Abeoconta in 
 West Africa. 
 
 Preparation, a. From Barberry-root. The root is exhausted with boiling water; 
 the extract concentrated by evaporation, and treated with warm alcohol of 82 per 
 cent; the solution filtered; the greater part of the alcohol distilled off; and the 
 residue left to itself in a cool place. Yellow crystals of berberine are then deposited, 
 and may be purified by recrystallisation from boiling water or alcohol. The root con- 
 tains about 1-3 per cent, of berberine. (Buchner.) 
 
 b. From Colombo-root. The dried alcoholic extract of the root is treated with hot 
 water ; the filtered solution neutralised with hydrochloric acid ; and the liquid again 
 filtered, treated with excess of hydrochloric acid, and left at rest for some days. It 
 then deposits a crystalline sediment of hydrochlorate of berberine, which is dissolved 
 in a small quantity of alcohol and reprecipitated by ether (Bodeker). For further 
 purification, the hydrochlorate is converted into a sulphate ; this salt is recrystallised 
 and dried at 100 C. ; the aqueous solution decomposed by baryta- water ; the excess of 
 baryta removed by passing a stream of carbonic acid through the liquid, then filtering, 
 evaporating nearly to dryness, and digesting the residue in alcohol. The alcoholic 
 solution is then precipitated by ether, and the precipitated berberine recrystallised 
 from water. The same mode of purification may be adopted with berberine obtained 
 from barberry -root. (Fleitmann, Ann. Ch. Pharm. xxiv. 228.) 
 
 Properties. Small silky needles or concentrically grouped prisms of a light yellow 
 colour. Odourless, but has a strong and persistently bitter taste. Sparingly soluble 
 in water and alcohol when cold ; easily at the boiling heat ; insoluble in ether. Oils, 
 both fatty and volatile, dissolve it in small quantity. 
 
 The crystals heated to 100 C. give off 19-26 per cent, (5 at.) water of crystallisa- 
 tion, and the residue contains 667 to 67'4 carbon, and 5-6 to 57 hydrogen, agreeing 
 
 * Or rather C 20 Hi 7 NO 4 (Perrins, Chem. Soc. J. xv. 339). See APPENDIX. 
 PP 2 
 
580 BERENGELITE BERGAMOT, OIL OF. 
 
 nearly with the formula C 21 H 19 NOUH 2 0, or C 4 WNO".HO (Fleitmann). The 
 remaining water cannot be expelled" without further decomposition. According to 
 Fleitmann, the anhydrous salts of berberine contain the group C 42 H IS N0 9 associated 
 with acids: e.g. the hydrochlorate = C*H l *N&.H<X; berberine dried at 100 is 
 0*H*N&$uO t and the crystals contain CHN0 9 .1HO + 10 aq. These formulae 
 are, however, by no means probable, and further examination is required to determine 
 the rational constitution of the base. The formula C 21 H 19 NO S or C'WJXO 10 is that 
 suggested by Grerhardt (Traite, iv. 205). 
 
 Berberine melts at 120 C. to a resinous mass, without loss of weight. Between 160 
 and 200 C. it gives off yellow odorous vapours, which condense into a solid body in- 
 soluble in water, but very soluble in alcohol, and leaves an abundant residue of charcoal. 
 Ammonia colours berberine yellow-brown, and dissolves it in nearly the same propor- 
 tions as water. Berberine boiled with caustic potash-ley melts, and is converted into 
 a resinous substance, sparingly soluble in water, easily in alcohol. According to 
 Bodeker, berberine distilled with milk of lime or hydrate of lead, yields chinoline. 
 
 The salts of berberine are, for the most part, sparingly soluble in water ; many of 
 them may be prepared by treating the hydrochlorate with a salt of potassium. Hydro- 
 chlorate of berberine, C 21 H 19 N0 5 .HC1 + 2H 2 0, crystallises in slender yellow needles, 
 which give off their water of crystallisation (8'65 per cent.) at 100 C. With sulphide 
 of ammonium containing excess of sulphur, it forms a foetid brown-red precipitate con- 
 taining sulphur. A hot alcoholic solution of the hydrochlorate mixed with a concen- 
 trated alcoholic solution of glycocine, yields on cooling, a mass of slender orange-coloured 
 needles, sparingly soluble in water, which appear to contain C 21 H 19 N0 5 .HC1.C 2 H 5 N0 2 (?) 
 The chloroplatinate of berberine, C 21 H 19 N0 5 .HCl.PtCl 2 (?) is a yellow precipitate nearly 
 insoluble in water. The chlorate, C 21 H 19 N0 5 .HC10 3 (?) is a bulky yellow precipitate 
 obtained by mixing the hydrochlorate with chlorate of potassium. It is moderately 
 soluble in pure water, sparingly soluble in saline liquids. The acid chromate, 
 C 21 H 19 N0 5 .Cr 2 H 2 4 (?) is a bulky yellow precipitate, sparingly soluble in water, ob- 
 tained by mixing the hydrochlorate with acid chromate of potassium. It is very 
 soluble in hydrochloric and sulphuric acids. When strongly heated, ^ it decomposes 
 suddenly, yielding a large quantity of the yellow substance produced in the dry dis- 
 tillation of berberine. Nitrate of berberine forms yellow crystals sparingly soluble in 
 cold water. The acid sulphate, C 21 H 19 N0 5 .SO'H 2 (?) is deposited after a while in small 
 yellow crystals on adding sulphuric acid to a dilute solution of the hydrochlorate. 
 
 XtERENGEXiXTi:. Berengela resin. A bituminous mineral found in the province 
 of St. Juan de Berengela in Peru, about one hundred miles from Arica, where it occurs 
 in amorphous masses of considerable extent, forming a sort of pitch-lake, like that of 
 Trinidad (p. 426). It has a conchoi'dal fracture, a dark brown colour, inclining to 
 green, and waxy lustre ; yields a yellow powder ; has a resinous unpleasant odour and 
 a rather bitter taste. Melts below 100 C., and after cooling remains soft and unctuous 
 at ordinary temperatures. It dissolves readily in cold alcohol and in ether. It is used 
 for caulking ships. According to Johnston's analysis (Phil. Mag. [3] xiv. 87), its 
 formula is 
 
 is a fine-grained granite containing pyrites, occurring at Beresowsk in 
 
 the Ural, in the rocks in which the gold veins are found. 
 
 BERGAIVIOT, OIIi OP. A volatile oil obtained by pressing the rind of a variety 
 of orange, Citrus bergamia, cultivated in the soiith of Europe. The oil thus obtained 
 is light-yellow or sometimes greenish or brownish-yellow ; mobile, with a very agreeable 
 odour and aromatic somewhat bitter taste. Specific gravity 0'869. It generally 
 exhibits an acid reaction, arising from the presence of a small quantity of acetic acid. 
 It solidifies a little below C., and at ordinary temperatures deposits, after a while, 
 a solid camphor or stearoptene. 
 
 Bergamot-oil is a mixture of two essential oils, the more volatile of which is isomeric 
 with oil of turpentine and oil of lemon, C 10 H 16 ; but it is difficult to separate this oil 
 by simple distillation. 
 
 The less volatile portion which, when rectified, boils at 183 C. and has a density 
 of 0-856, contains oxygen, and according to Ohme (Ann. Ch. Pharm. xxxi. 316), 
 has the composition of a hydrate of oil of lemon, 30 10 H 16 . 2H 2 0. According to 
 Soubeiran and Capitaine (J. Pharm. xxvi. 68, 509), this portion of the oil is not 
 'of constant composition, but yields by fractional distillation, oils continually increas- 
 ing in amount of oxygen, from 3'37 to 16-14 per cent, (perhaps the oil was oxidised 
 during the distillation). They find also that the first portions turn the plane of 
 polarisation of a luminous ray to the right, but that the subsequent portions exhibit 
 less and less of this power, and finally none. 
 
 Ohme's rectified bergamot-oil is not altered by caustic potash. Its vapour passed 
 over red-hot lime yields a large quantity of benzene. It absorbs hydrochloric acid 
 
BERTH1ERIN-BER YL. 
 
 581 
 
 gas abundantly, forming a liquid compound, which, after being shaken up and distilled 
 with water, has the specific gravity 0*896 ; boils at 183 C., and contains C 60 H 100 C1 2 O, 
 or 6C 10 H IC .2HC1.H 2 0. 
 
 Bergamot-oil placed in contact with phosphoric anhydride becomes heated, and 
 afterwards yields by distillation an oil smelling like oil of turpentine, and having 
 exactly the composition C'H 16 . The residue of the distillation contains a conjugated 
 acid, phosphobergamic acid, which forms soluble salts with calcium and lead. 
 
 BERGAMOT- CAMPHOR, Bergaptcne, Stearoptene of bergamot-oil, is a solid sub- 
 stance deposited by crude oil of bergamot after long keeping. It crystallises in 
 needles, melts at 206 C., and volatilises without decomposition. It^is odourless and 
 dissolves in boiling water, alcohol, and ether. Strong sulphuric acid colours it red. 
 Heated with nitric acid, it yields oxalic acid. It gives by analysis about 66'2 per cent, 
 carbon and 3 - 8 hydrogen, numbers answering to the formula C 3 H 6 2 , but the ra- 
 tional formula is not yet determined. (Mulder, Ann. Ch. Pharm. xxxi. 70 ; Ohme, 
 loc. tit.} 
 
 BERTHXERXCT. The name given by Beudant to a ferruginous mineral occurring 
 in small grains, resembling iron-spar or brown iron ore; but whether it is a definite 
 .species or a mixture is not decidedly known. According to Berthier, it contains 12'4 
 per cent, silica, 74'7 protoxide of iron, 7'S alumina, and 5*1 water. The same name 
 is also applied to a mineral from Hayanges near Metz, of greyish-green or liver-brown 
 colour, which', under the microscope, appears like an oolitic rock, consisting of a 
 greenish amorphous mass, containing innumerable small flattened needles of brown 
 iron ore. 
 
 BERTHXERXTE or HAH>I3MGEK,IT. These names are applied some- 
 what indiscriminately to three minerals, containing protosulphide of iron, together 
 with trisulphide of antimony. a. 3Fe 2 S.2Sb 2 S 3 . Found at Chazelles in Auvergne, 
 crystalline or massive, with imperfect cleavage in several directions. Specific gravity 
 4-284: : hardness 2*0 ito 3*0. Iron-black or dark steel-grey. Opaque with metallic 
 lustre. Fuses readily before the blowpipe on charcoal, yielding antimonial fumes 
 and deposit, and leaving a black magnetic slag (Berthier, Ann. Ch. Phys. [2] xxxv. 
 351). b. 3Fe'-S.4Sb 2 S 3 . Found in a mine near Chazelles. Fibrous, with granular 
 transverse fracture, almost destitute of lustre (Berthier, Pogg. Ann. xxix. 458). 
 c. Fe 2 S.Sb 2 S 3 or FeSbS 2 . Found at Anglar in the Departement de la Creuse. Crystal- 
 line, composed of fine parallel fibres. Steel-grey, inclining to bronze (Berthier). 
 Minerals having this composition are also found in other localities. 
 
 BEHTHOXiXiSTXA SXCEXiSA. A Brazilian tree belonging to the order Lccy- 
 thidacece. The kernels of the fruit, called Brazilian or Pava nuts, contain sugar, gum, 
 and a pale yellow odourless fat oil, which solidifies at C., and contains stearin, 
 palmitin, and elain. (Caldwell, Ann. Ch. Pharm. xcviii. 120.) 
 
 BERYL. 3G1 2 . A1 4 3 . 6Si0 2 Si 3 GPAL 2 !? . A mineral species comprising several 
 varieties, among which are found two very beautiful and costly gems, viz. emerald, and 
 aquamarine or precious beryl. The crystals belong to the hexagonal system, being 
 regular six-sided prisms variously modified, sometimes by the truncation of the lateral 
 edges, at other times of the terminal edges. The most ordinary combinations are 
 oo P . oP and ooP . oP . P. (fig. 98) ; sometimes, however, much more complicated 
 modifications occur, like fig. 99, composed of the hexagonal prism oo P. the terminal 
 
 Fig. 98. 
 
 Fig. 99. 
 
 face oP, the primary hexagonal pyramid P, a sharper hexagonal pyramid of the first 
 
 order 2P, a pyramid of the second order 2 P 2, and a symmetrical 12-sided pyramid 
 
 i Pf, whose faces (denoted in the figure by z) replace the combination-edges between 
 
 2P2, and oc P. The prismatic faces are often deeply striated in the vertical direc- 
 
 pp 3 
 
582 BERYLLIUM BETA. 
 
 tion. Cleavage tolerably perfect, parallel to oP. Fracture conchoi'dal and uneven 
 Specific gravity 2*67 to 276. Hardness 7'5 to 8*0. The most usual colour of the 
 beryl is green, of various shades between yellow- and blue-green, arising from the 
 presence of iron in various stages of oxidation ; yellow, blue, rose-coloured, and co- 
 lourless beryls are also found. The brilliant green of the emerald is due to the 
 presence of oxide of chromium. Lustre vitreous. The best specimens of emerald 
 and aquamarine are perfectly transparent; but the transparency is generally greatly 
 diminished by cracks and striae, the coarser varieties being opaque in the mass and 
 translucent only at the edges. Beryl is difficult to fuse by itself before the blowpipe, 
 melting to a glass at the edges only ; with borax it fuses readily to a transparent 
 glass ; with phosphorus-salt, it leaves a skeleton of silica. 
 
 Beryl from Limoges was found by C. Grmelinto contain 67'54 SiO 2 , 17'63 A1 4 3 , and 
 13-51 Grl-O (= 98'68) ; a specimen from Fahlun, analysed by Berzelius, gave 68'35 
 SiO-, 17-60 A1 4 3 , 13-13 Gl-'O, 072 1V0 3 and 072 TaO 2 . These and numerous other 
 analyses agree nearly with the formula above given (calc. 67'46 SiO 2 , 1874 A1 4 3 , 
 13-80 CHO), which, by substituting al = |A1, may be reduced to that of a metasilicate 
 (G-laJ) SiO 3 . 
 
 Beryls are found in various parts of the world; the finest emeralds come from 
 Peru, where they are found traversing clay-slate, hornblende slate, and granite ; fine 
 specimens are also obtained from Katharinenburg in Siberia ; inferior varieties from 
 the Heubach valley in the district of Pinzgau in Salzburg ; varieties are also found 
 in some old mines in Mount Zabarah in Upper Egypt, from which spot the ancients 
 are supposed to have derived their emeralds. Fine transparent beryls or aqua- 
 marines are found in Brazil, in the granite district of Nertschinsk in Siberia, in the 
 Ural and Altai mountains, and in the granite of the Morne mountains in the county of 
 Down, Ireland. Opaque beryls, sometimes of very large size, are found at Langenbilau 
 in Silesia ; at Bodenmais in Bavaria, near Limoges in France ; at Kinloch, Kunnoch, 
 and Cairngorm, Aberdeenshire ; and in the counties of Dublin and Wicklow. Between 
 the Connecticut and Marimac rivers, near Crofton in North America, enormous 
 specimens have been found, measuring from 4 to 6 feet in length, and weighing between 
 2000 and 3000 pounds. 
 
 BERYXiXiXTTlVX. Syn. with GI/UCESTUM. 
 
 BERZEXiXAXTXTE. Selenide of Copper. 
 
 BERZEXiXXTE. Berzelitc, Kuhnite, Chaux arseniate anhydre, Magnesian Phar- 
 macolite. As 2 (Mg 3 Ca 3 )0 8 . A massive mineral occurring near Langbanshytta in 
 Sweden. It has an uneven fracture, and exhibits traces of cleavability in one direc- 
 tion. Yellowish- white to honey -yellow, with waxy lustre; translucent on the edges. 
 Perfectly soluble in nitric acid. Before the blowpipe, it exhibits the usual reactions 
 of arsenic, and with soda shows evidence of a trace of manganese. (Kiihn, Ann. Ch. 
 Pharm. xxxiv. 271.) 
 
 BERZEXiXTT. A mineral found in the older volcanic ejections near Lake Albano 
 in Italy, together with hauyne, augite, and mica. It crystallises in octahedrons or 
 dodecahedrons, belonging to the regular system, sometimes forming twin-crystals; 
 cleavage tolerably distinct, parallel to the faces of a cube. The crystals are often 
 uneven a*nd rounded. It occurs also in spherical and stalactitic forms, massive and 
 imbedded. Fracture varying from conchoi'dal to uneven ; colour white or grey ; lustre 
 vitreous to dull ; varies from transparent to perfectly opaque ; streak white ; hard- 
 ness o'O ; specific gravity 2*428 to 2727. According to an imperfect analysis by 
 L. Cmelin, its composition is similar to that of leucite. When pulverised and ignited, 
 it yields a small quantity of water. Melts with difficulty before the blowpipe to a 
 tumefied glass ; with borax readily to a clear glass. Dissolves slowly in nitric acid, 
 yielding a jelly of silica when heated. Similar crystals have been found in nephelin- 
 dolerite from Meiches in Oberhessen. (Handw. d. Chem. ii. [1] 1023.) 
 
 The same name has been applied to native selenide of copper. 
 
 BERZEXiXTE. This name has been given to Mendipite, Petalite, Thorite, and 
 Berzeliite. 
 
 BETA, Beet. A genus of plants, belonging to the natural order Chenopodiacese,. 
 distinguished by the large quantity of sugar contained in their roots. The three 
 principal species are: 1. Beta vulgaris, common beet, well known for its sweet crimson 
 roots, which are used as a salad. 2. Beta cycla, chard beet, inferior in the size and 
 flavour of its roots, but distinguished by its remarkably thick-ribbed leaves, which are 
 used in France in soups ; or the ribs only are cut out and stewed like sea-kail. 
 3. Beta altissima, field-beet or mangold- wurzel, sometimes, though erroneously, regarded 
 as a hybrid between the two former. This is by far the most important species, as it 
 is extensively cultivated for feeding cattle, and in France and Germany also for the 
 extraction of sugar. 
 
BETULIN BEZETTA. 
 
 583 
 
 The root of mangold- wurzel contains crystallisable sugar, identical in every respect 
 with cane-sugar. Payen gives for the average composition of the root, 83'5 per cent, 
 water, 10*5 sugar, 0'8 cellular substance and pectose, 1*5 nitrogenous matter (albumin, 
 &c.), and 3'7 pectin and salts. The salts consist of nitrates and ammonium-salts, toge- 
 ther with alkaline and earthy phosphates, sulphates, chlorides, oxalates and malates, or, 
 according to some chemists, citrates. The root has also been stated to contain two or 
 three peculiar acids, which have not been thoroughly examined. The dried leaves 
 contain, according to Sprengel, 15'44 per cent. ash. The seed contains 11-6 per cent, 
 water, and in 100 pts. of dry substance, - 09 sulphur and 6'58 ash. (Way and 
 Ogston.) 
 
 The following table exhibits the composition of the ash of the seed, leaves, and roots : 
 
 
 Ash of seed. 
 
 Ash of leaves. 
 
 Ash of roots. 
 
 
 Way. 
 
 Ogston. 
 
 Sprengel. 
 
 Etti. 
 
 Potash (anhydrous) 
 
 16-1 
 
 36-3 
 
 23-9 
 
 19-5 26-6 
 
 Soda ... 
 
 6-8 
 
 21'3 
 
 53-1 
 
 22-430-5 
 
 
 13-4 
 
 14-9 
 
 4-8 
 
 3-2-- 4-5 
 
 Magnesia ..... 
 
 15-2 
 
 5-4 
 
 2-2 
 
 7-0 9-8 
 
 Alumina and ferric oxide 
 Manganic oxide .... 
 
 0-4 
 1-8 
 
 1-1 
 
 0-4 
 
 j 2-3 
 
 o-i o-i 
 
 Silica 
 
 
 
 27 
 
 1-8 
 
 14-119-8 
 
 Sulphuric acid (anhydrous) . 
 
 3-6 
 
 6-3 
 
 2-1 
 
 2-5 2-5 
 
 Phosphoric 
 
 13-1 
 
 4-5 
 
 2-8 
 
 2-4 2-4 
 
 Chlorine 
 
 
 
 6-9 
 
 6-3 
 
 1-4 1-9 
 
 Carbonic acid (anhydrous) . 
 
 13-8 
 
 
 
 
 Chloride of sodium 
 
 15-3 
 
 
 
 
 BETUXiXia*. C 40 H 64 3 . A resinous substance extracted from the outer bark of 
 the birch-tree (Betula alba), or from the tar prepared therefrom. It was discovered 
 by Lowitz (Crell. Chem. Ann. 1788, i. 302), and analysed by Hess (J. pr. Chem.xvi. 
 161). It belongs to the series of resins, including sylvic acid, which are produced by 
 oxidation from hydrocarbons of the form C 5n H 8n . To extract it, the dried bark is ex- 
 hausted with boiling water, then dried again and treated with boiling alcohol. The 
 solution on cooling deposits the betulin, which is pressed, dried, and recrystallised 
 from ether. It forms small crystalline nodules, which melt at about 200 C. The 
 melted matter is colourless and transparent, and gives off vapours which smell like the 
 bark when heated. It may be distilled in a current of air. It is not dissolved by alkalis. 
 
 BETITIiORETIC ACID. According to Kossmann (J. Pharm. [3] xxiv. 197) 
 birch-resin consists of an acid, C 36 H 65 5 , which is converted by nitric acid into picric 
 acid, but is not decomposed by sulphuric acid. 
 
 See NEPHELIN. 
 
 BEUD AXJTITE. A ferruginous mineral occurring at Horhausen and Montabaur 
 in Nassau, and near Cork in Ireland. It crystallises in rhombohedrons cleavable 
 parallel to the base, and having the rhombohedral faces horizontally striated. Colour 
 black to olive-green. Streak light green. The fresh crystals have a waxy lustre. 
 Hardness above 4*0. The Nassau mineral has a specific gravity of 4*0018, and melts 
 readily before the blowpipe (S a n d b e r g e r). The Irish variety has a specific gravity of 
 4-295, and is infusible (Eammelsberg). It contains sulphate of lead, associated with 
 ferric sulphate, arsenate, and phosphate, the two latter replacing each other isomor- 
 phously ; it also contains water (Pavy, Phil. Mag. [3] xxxvii. 161). According to 
 Eammelsberg, it is 2(Pb 2 O.S0 3 ) + Fe 4 4 .S0 3 + 3Fe 4 3 .P 2 5 + 9H 2 0; according to 
 Sandberger, Pb-O.SO 3 + 3Pb*0(As ? 5 ; P 2 5 ) + 3[3Fe 4 3 (As 2 O s ; P 2 5 )] + 24H 2 0. 
 (Handw. d. Chem. ii. 1029.) 
 
 BEZETTA. Tourncsol en drapcaux. SchminJelappchen. TSezetta rubra et 
 coerulea. A dye or pigment prepared by dipping linen rags in solutions of certain co- 
 louring matters. Eed bezetta is coloured with cochineal, and is used as a cosmetic. 
 
 Blue bezetta ( Tourncsol en drapcaux), which is chiefly used for colouring the rind 
 of Dutch cheeses, is prepared at Gallargues near Nimes in the department of Gard, 
 from a euphorbiaceous plant, Chrozophora tinctoria or Croton tinctoria. The fruits 
 and the tops of the plants are gathered, and the juice being expressed, rags of coarse 
 cloth are dipped into it, then dried, and afterwards exposed to the fumes of mules' or 
 horses' dung. This last operation is called aluminadou. The cloths are turned from 
 time to time, to ensure uniform coloration and prevent any part from being exposed 
 
 p p 4 
 
58 i BEZOAR BILE. 
 
 too long to the fames of the dung, which would turn them yellow. They are then 
 dried a second time, again soaked in the juice, mixed this time with urine, and lastly 
 exposed for some time to the action of the sun and wind. The quantity thus manufac- 
 tured amounts to about 50 tons yearly. The blue of bezetta is reddened by acids, like 
 litmus, though not so quickly, but differs from the latter in not being restored by al- 
 kalis. According to Joly, the same dye may be obtained from other euphorbiaceous 
 plants, Chrozophora oblongata, C. plicata, Croton tricuspidatum, Mcrcurialis perennis, 
 and M. tormentosa. The juice exists in all these plants in the colourless state, and 
 turns blue only on exposure to the air. (Handw. d. Chem. ii. [1] 1030; Gerh. 
 Traite, iii. 820.) 
 
 BEZOAR. This name, which is derived from a Persian word implying an anti- 
 dote to poison, was given to a concretion found in the stomach or intestines of an 
 animal of the goat kind, Capra cegragus, which was once very highly valued for this 
 imaginary quality, and has thence been extended to all concretions found in animals. 
 
 According to Taylor (Phil. Mag. No. 186 p. 36 and No. 186 p. 192), bezoars may 
 be divided into nine varieties : 1. Phosphate of calcium, which forms concretions in 
 the intestines of many mammalia. 2. Phosphate of magnesium : semitransparent and 
 yellowish, and of specific gravity 2'160. 3. Phosphate of ammonium and magnesium : 
 a concretion of a grey or brown colour, composed of radiations from a centre. 
 4. Oxalate of calcium. 5. Vegetable fibres. 6. Animal hair. 7. Ambergris. 
 8. Lithofellic acid. 9. Ellagic or bezoardic acid. 
 
 Of true bezoars there are three kinds, oriental, occidental, and German. The 
 true oriental bezoars found in the Capra cegragus, the gazelle (Antilope Dorcas), 
 and other ruminant animals, are spherical or oval masses, varying from the size of a 
 pea to that of the fist, and composed of concentric layers of resinous matter with a 
 nucleus of some foreign substance, such as pieces of bark or other hard vegetable 
 matter which the animal has swallowed. They have a shining resinous fracture, are 
 destitute of taste and odour, nearly insoluble in water and aqueous hydrochloric acid, 
 but soluble for the greater part in potash-ley. When heated, they emit an agreeable 
 odour and burn away, leaving but a small quantity of ash. These characters suffice to 
 distinguish the oriental bezoars from those varieties which contain a considerable 
 quantity of inorganic matter. There are two kinds of them, the one consisting of ellagic, 
 the other of lithofellic acid. The latter have a more waxy lustre and greener colour 
 than the former, and are also distinguished by their smaller specific gravity, viz. I'l, 
 while that of the ellagio acid stones is l - 6. They contain, besides lithofellic acid, a 
 substance resembling the colouring matter of bile, and are perhaps biliary calculi. 
 Oriental bezoars are greatly prized in Persia and other countries of the East for their 
 supposed medicinal properties. The Shah of Persia sent one in 1808 as a present to 
 Napoleon. 
 
 The occidental bezoars are found in the lama (AucTicnia Lama), and in A. Vicunna : 
 they resemble the oriental in external appearance, but differ totally in their chemical 
 characters, inasmuch as they consist chiefly of phosphate of calcium, with but little 
 organic matter. 
 
 German bezoars, which are chiefly obtained from the chamois or gemsbock (Antilope 
 rupicapra), consist chiefly of interlaced vegetable fibres or animal hairs bound together 
 by a leathery coating. 
 
 ACID. Syn. of ELLAGIC ACID. 
 
 An antiquated medicament made from the dried 
 hearts and livers of vipers, and supposed to be an antidote against poison -. hence its 
 name. 
 
 BEZOARDXCITIM IVIZNERAXiE. A name applied by the older chemists to 
 antimonic acid, especially to that prepared from butter of antimony by the action of 
 nitric acid. 
 
 BI-COIVTPOTTNDS. See Di-CoMPOUNDS and NOMENCLATURE. 
 
 BIXiDSTEIN. Syn. with AGALMATOLITE. 
 
 BXIiE. Gall. Galle. (L ehm an n, "Physiological Chemistry," Cavendish Society's 
 Edition, ii. 61; also Gmelin's Handbuch, viii. 38. Strecker, Ann. Ch. Pharm. 
 
 Ixv. 1; btvii. 1; hex. 149. Gundelach and Strecker, ibid. Ixii. 205) Bile, as 
 
 secreted by the cells of the liver, is taken up by the biliary ducts, which unite to form the 
 hepatic duct, by which the secretion is either discharged directly into the duodenum, or 
 is conveyed through the cystic duct into the gall-bladder, wherein it becoines accumu- 
 lated and to some extent inspissated. Cystic bile when taken from a healthy animal 
 recently killed, is a mucous, transparent, ropy liquid, of green or brown colour. 
 It has a bitter but not astringent taste, sometimes leaving a sweetish after-taste, and a 
 peculiar odour, which, when the bile is warmed, is often very much like that of musk. 
 
BILE. 585 
 
 Its specific gravity is about 1-02. It does not diffuse itself readily through water, 
 unless the mixture be stirred. Its reaction is, for the most part, faintly alkaline, some- 
 times neutral, never acid, excepting in peculiar states of disease. Bile in its ordinary 
 state, before the mucus is removed, putrefies very readily ; but when freed from mucus, 
 it is much less prone to putrefactive decomposition. 
 
 The chemical composition of bile varies to a certain extent according to the nature 
 of the animal which yields it ; but every kind of bile contains two essential constituents, 
 viz. a resinous and a colouring matter, associated with small quantities of cholesterin, 
 fats, salts of fatty acids, and certain mineral salts, chiefly chloride of sodium and 
 phosphates, with smaller quantities of phosphate and carbonate of sodium, phosphate 
 of calcium, phosphate of magnesium, and extremely minute quantities of iron and 
 manganese, but no alkaline sulphates. No salts of ammonia are found in fresh healthy 
 bile, but during the putrefaction of bile, ammonia is produced. Bile also contains 
 mucus mixed with cells of epithelium. 
 
 The resinous matter of bile is the most abundant and important of its consti- 
 tuents. It consists, in nearly all cases, of the sodium or potassium salts of two nitro- 
 genised acids, one containing sulphur, the other free from that element. The former 
 of these acids, called taurocholic acid, is resolved by the action of alkalis into 
 tcuirlne and cholic acid, a crystalline acid containing neither nitrogen nor sulphur, and 
 changing, under certain circumstances, into an amorphous isomeric acid called cho- 
 loidic acid, differing from it only by the elements of water : 
 
 C 26 H 45 NS0 7 + H 2 = C 2 <H 4 5 + C 2 H 7 NS0 8 ; 
 Taurocholic Cholic Taurine. 
 
 acid. acid. 
 
 and the latter, called glyco cholic acid, is resolved in like manner into cholic acid 
 and glycocine : 
 
 H 2 = C 24 H 40 5 + C 2 H 5 N0 2 
 
 Glycocholic Cholic Glycocine. 
 
 acid. acid. 
 
 All kinds of bile, excepting that of the pig, contain one or both of these acids. Pig's 
 bile contains an acid called glyco-hyocholic acid, analogous to glycocholic acid, 
 and, like that compound, resolvable by the action of alkalis into glycocine and hyocholic 
 acid, an acid not containing nitrogen : 
 
 C 2r H 43 N0 5 + H 2 = C 25 H 4 0< + C 2 H 5 N0 2 . 
 
 Glycohyo- Hyocholic Glycocine. 
 
 cholic acid. acid. 
 
 The colouring matter of bile, bile-pigment, or cholochrome, is also a nitrogenised 
 acid, and is decomposed by nitrous acid, with evolution of nitrogen and formation of a 
 crystallised acid, cholochromic acid, which is free from nitrogen. (Thudichum, 
 Chem. Soc. Qu. J. xiv. 114.) 
 
 The bile of carnivorous and omnivorous animals, including man, contains a brown 
 pigment, the cholepyrrliin of Berzelius : that of birds, fishes, and amphibia has usually 
 an intense green pigment, biliverdin. The brown pigment is always combined either 
 with soda or with lime ; in the latter case, it is insoluble, and appears in the form of 
 brown granules when the bile is examined by the microscope. 
 
 The analysis of bile is conducted as follows : 
 
 The bile is first mixed with half its volume or more of 83 per cent, alcohol, which 
 throws down mucus and epithelium; the precipitate is rinsed with spirit, then 
 with water, afterwards dried and weighed. 
 
 The bile thus freed from mucus, is evaporated to dryness, first over the water-bath 
 and then under the air-pump on a sand-bath heated to 100 C. ; the residue is left to 
 cool in vacuo, after which, air dried by passing over chloride of calcium is introduced 
 into the receiver, and the weighing is completed as quickly as possible, because the 
 dried bile is extremely hygroscopic. 
 
 The residue is next digested for a considerable time with ether, which takes up fat 
 and cholesterin. The total quantity of these matters may then be determined by 
 evaporating the ethereal extract; but the different substances contained in it cannot be 
 separately estimated, unless very large quantities of bile are operated upon ; in that 
 case, the fatty acids (stearic and margaric or palmitic acids) may be separated from 
 the. cholesterin by precipitation as lead-salts. 
 
 The residue insoluble in ether, which contains the essential constituents of the bile, 
 is next to be treated with cold absolute alcohol, which dissolves the salts of the biliary 
 acids, together with part of the bile-pigment ; the greater part of the alcohol is then re- 
 moved by evaporation ; ether added to the concentrated solution as long as any tur- 
 bidity is produced ; and the liquid left to stand for some time in a cool place. 
 
 The alkaline taurocholate and glyco cho late are thereby precipitated, and 
 
586 BILE. 
 
 their quantity may be estimated by washing the precipitate with ether, and weighing 
 it after drying over the water-bath. It always, however, contains a certain portion of 
 bile-pigment, which cannot be completely separated unless it consists of pure chole- 
 pyrrhin, in which case it may be separated by chloride of calcium. The quantity of 
 soda or potash associated with the biliary acids and the bile-pigment, may bo 
 determined by decomposing a weighed portion of the ether-precipitate with sulphuric 
 acid. 
 
 The taurocholic and glycocholic acids cannot be completely separated one from the 
 other. An approximate separation may be effected by dissolving the precipitate in 
 alcohol, and treating it with neutral acetate of lead, which precipitates only the glyco- 
 cholic acid ; but the best way of estimating the relative quantities of the two acids, is 
 to determine the amount of sulphur in the ether-precipitate, by fusing it with nitre or 
 by one of the other methods given under ANALYSIS (ORGANIC), p. 225. Every 6pts. of 
 sulphur correspond to 100 pts. of taurocholate of sodium. 
 
 The residue of the bile, insoluble in absolute alcohol, must nowbe determined with the 
 view of checking the analysis. It contains pigment, partly free and partly combined 
 with lime; also alkaline and earthy phosphates, with chloride and carbonate of 
 sodium, very rarely sulphate of potassium, but often a little taurine ; its amount is 
 generally too small to allow of the quantitative separation of these substances, unless 
 very large quantities of bile are operated upon. Altogether the determinations which 
 have been made of the amount of pigment, cholesterin, fats, fatty acids, and mineral 
 constituents of bile, cannot be regarded as more than approximations to the truth. 
 
 Pette nkofer's Test for Bile When bile is mixed with a strong syrup of sugar, and 
 then with strong sulphuric acid, so that it becomes heated, it assumes a deep violet-red 
 or purple tint, which disappears on addition of water. This reaction is produced by 
 cholic, choloidic, glycocholic, and taurocholic acids (or the corresponding acids in pig's 
 bile), but not by any other substance ; it is, therefore, perfectly characteristic of bile, 
 and affords a very delicate indication of its presence. The best mode of applying it 
 for the detection of small quantities of bile in blood or other animal fluids, is as 
 follows : The alcoholic extract of the liquid to be tested for biliary matter, is dissolved 
 in a little water, and mixed with a single drop of a solution of sugar (1 pt. of sugar to 
 4 pts. of water), and pure strong sulphuric acid is then added by small quantities, till 
 the turbidity at first produced, disappears, cooling after each addition ; it then for a 
 few moments exhibits a yellowish colour, which, however, soon changes to a pale cherry- 
 red, then to deep carmine, then to purple, and finally to an intense violet tint. For 
 the success of the experiment, care must be taken not to add too much sugar ; other- 
 wise a black mass will be formed, which will completely mask the reaction. The 
 temperature of the mixture must be allowed to rise to about 50 C. but not higher. 
 The reaction takes place with any kind of sugar, and likewise with acetic acid. 
 
 Composition of the Bile of various animals. Human bile consists mainly of tauro- 
 chlorate of sodium, with very little glycocholate (Gorup-Besanez). Ox-bile, on 
 the contrary, contains chiefly glycocholate (Strecker). Pig-bile, as already ob- 
 served, consists mainly of the sodium-salt of an acid analogous to glycocholic acid ; viz. 
 glycohyocholic acid (Gundelach and Strecker), together with a small quantity 
 of a sulphuretted acid, yielding taurine by decomposition : tauro-hyocoholic acid ; it 
 likewise contains a very strong base containing sulphur. 
 
 The bile of most other animals consists mainly of taurocholate of sodium or potas- 
 sium. That of the dog contains only taurocholate of sodium ; that of the sheep, and 
 that of the kangaroo contain taurocholate, with very little glycocholate. In the bile 
 of several kinds of fish, viz. turbot, cod, pike, and perch, Strecker found taurocholate, 
 with mere traces of glycocholate ; a similar result was obtained by Schlossberger 
 (Ann. Ch. Pharm. cviii. 166) with the bile of the shad-fish. According to (Bensch 
 (Ann. Ch. Pharm. Ixv.) and Strecker, the bile of sea-fish contains potassium-salts, 
 that of fresh-water fish chiefly sodium-salts. The bile of the Boa Anaconda (Schlie - 
 per, Ann. Ch. Pharm. Ix. 109) and that of the Python tigris (Binder, ibid. cii. 91) 
 consist mainly of taurocholate. Goose-bile appears likewise to consist essentially of 
 taurocholate of sodium, though Marrson (Arch. Pharm. [2] Iviii. 138), and more 
 recently Heintz andWisliscenus (Pogg. Ann. cviii. 547) state that the sulphuretted 
 acid of goose-bile differs in composition from taurocholic acid; Heintz and Wis- 
 liscenus assign to it the composition C 29 H 49 NS0 6 ; but the analyses are not quite 
 satisfactory. 
 
 Taurocholate of sodium contains about 6 per cent, of sulphur : now in the dried 
 bile of the dog, Bensch found 6 '2 per cent, sulphur ; in that of the fox, 5'96 per cent. ; 
 of the wolf 5-03 ; of the bear 5'75 ; of the pig 0'32 ; of the calf 5'62 ; of the sheep 6'46 ; of 
 the goat 5'99 ; of the domestic fowl 5'57 ; and of several fishes 6*46 per cent. 
 
 In normal human bile, Frerichs fcmnd 14 per cent, or rather more of solid consti- 
 tuents ; Gorup-Besanez, in the bile of two recently executed criminals, found 10'19 
 
BILE. 587 
 
 and 1773 per cent, solid matter; in that of an old man, 9*13 per cent; and in that of 
 a boy of twelve years old, 17*19 per cent, solid matter. Ox-bile contains 10*13 per 
 cent, solid constituents ; pig's bile 10'6 to 11-08 per cent. (Gun delach andStrecker); 
 dog's bile 5*1 per cent. ; cat's bile 5*6 per cent. (Bidder and Schmidt) ; sheep's bile 
 5 '3; rabbit's bile 1*8; goose bile 6'9 ; kangaroo's bile 14*13 ; and crow's bile 7*3 ; per cent, 
 solid constituents. The concentration of the bile appears to increase with the time it 
 remains in the gall-bladder. 
 
 The proportion of ash in the dried residue amounts in normal human bile to 6'14 
 per cent. Gorup-Besanez), in ox-bile to 127 (Berzelius); in calf's bile to 13*15 
 (Bensch) ; in sheep's bile to 11*86; in goat's bile to 13*21 ; in pig's bile to 13'6; in 
 fox bile to 1271 ; in that of the domestic fowl to 10*99 ; in that of fresh-water fish, 
 to 14*11 per cent. ; in that of the fresh- water turtle (Emys geographicd) to 5*5 ; and in 
 that of the salt-water turtle (Emysinsculpta) to 6*3 per cent. (Wetherill, J. pr. Chem. 
 Ixxvi. 61). The fresh bile of Python tigris yields 1*21 per cent, of ash. 
 
 Ox-bile extracted from the gall-bladder without pressure, contains 0*134 per cent. 
 mucus; human-bile 0*158 per cent. (Lehman n); Gorup-Besanez found in human bile 
 1*45 and 2 - 21 per cent, mucus and bile-pigment. The bile of the kangaroo contains 
 4*34 per cent, mucus and colouring matter, and 1*09 cholcsterin and fat; that of the 
 shad-fish contains 1*28 per cent, mucus and colouring-matter, and 0*23 per cent, fat; 
 that of Python tigris, contains 0*89 per cent, mucus and 0*03 fat ; goose-bile contains 
 2*56 per cent, mucus, 0*36 fat and cholcsterin. (Marrson.) 
 
 The bile, like all the other normal secretions, is liable to alteration from disease, and 
 sometimes contains heterogeneous constituents. Albumin is sometimes found in it, 
 especially in fatty liver, in Bright's disease, and in the embryonic state. Urea has 
 been found in the bile, in cases of fatty degeneration of the kidneys, and in animals 
 whose kidneys have been extirpated ; also in cholera. Bizio once discovered a dark- 
 red non-bitter bile in a patient suffering from jaundice; it contained an emerald- 
 green pigment, to which he gave the name of crythrogen, from its volatilising at 40 C. 
 and giving off a red vapour. A similar substance was found by Lehmann in a case of 
 acute yellow atrophy of the liver. In the bile of a child who died suddenly, Lehmann 
 found a considerable quantity of sulphide of ammonium, but the previous history of the 
 case was not known. 
 
 The normal constituents of the bile also vary in proportion, in various cases of 
 disease. The bile has been found to be poor in solid constituents, in persons who have 
 died from severe inflammatory affections, especially from pneumonia, and likewise in 
 fatal cases of dropsy ; it also contains an excess of water in diabetes, and in certain 
 cases of typhus ; in other cases of that disease, however, the bile becomes thicker than 
 in health. The solid constituents of the bile are commonly increased in those abdo- 
 minal diseases in which the motion of the blood in the larger veins is impeded, and in 
 certain cases of heart-disease, in which the blood accumulates in excessive quan- 
 tity in the hepatic veins. In cholera, the bile is also found to be dense, tough, 
 and consistent. The proportion of mucus is often increased when the bile is very- 
 dilute; indeed in typhus, the gall-bladder sometimes contains scarcely anything 
 else, the resinous constituents being almost, if not altogether absent ; the same is 
 observed in catarrh of the biliary ducts. (Lehmann.) 
 
 The separation of crystals of cholesterin, which is sometimes, though rarely, observed 
 in morbid bile, appears to be associated with an increase in the relative quantity of 
 that substance ; this phenomenon has been observed by Gorup-Besanez in very con- 
 centrated bile. Free fat is always present in the bile, but in the normal state is held 
 in solution by the taurocholate of sodium ; fat globules have, however, been observed 
 by Gorup-Besanez in the bile of persons who have died from typhus, and from tuber- 
 culosis in the colliquative stage. (Lehmann.) 
 
 The bile is very seldom acid ; an acid reaction has been observed in typhus, but it 
 may have arisen partly from spontaneous decomposition after death, partly from 
 effusion of pus into the gall-bladder : for pus, when contained in an enclosed space, 
 often becomes acid with great rapidity. (Lehmann.) 
 
 Putrefaction of Bile. When bile is left to itself, either in a closed or in an open 
 vessel, it undergoes gradual decomposition, acquiring an offensive odour and acid re- 
 action, and yielding a solid deposit containing cholic acid and other substances. 
 Thudichum (Chem. Soc. Qu. J. xiv. 118) found that ox-bile left for a year or 
 two in large bottles, well stoppered, and completely filled with it, had assumed a 
 slight acid reaction, a bright port wine colour, and had deposited a copious, flaky, 
 green and brown deposit, mixed with white chalk-like particles and greenish crystals. 
 This deposit was found to consist of cholochrome (bile-pigment) cholic acid, phos- 
 phate of calcium and magnesium in dichroic crystals, and mucus. The fluid part of the 
 bile was found to contain principally choloidate of sodium with a little cholate ; also 
 tuurine, valeratc and acetate of sodium, and of ammonium, and phosphate of sodium, 
 
588 BIMSTE1N BIRCH. 
 
 but no glycocine, glycocholic acid, or taurocholic acid. The decomposition appears 
 to begin by the resolution of the glycocholate of sodium into cholate of sodium and 
 glycocine, and of the taxirocholate into cholate and taurine. The ammonia and acetic 
 acid are probably formed by the decomposition of the glycocine (oxyacetamic acid) ; 
 the origin of the valeric acid is obscure ; these acids unite with a portion of the soda 
 and precipitate some of the cholochrome and cliolic acid, the rest of that acid remain- 
 ing in solution as choloidate of sodium. From the experiments of Grorup-Besanez 
 (Ann. Ch. Pharm. lix. 129) it appears that bile allowed to decompose in an open 
 vessel, at a comparatively high temperature, 25 to 30 R., deposited chiefly choloidic 
 acid, but when the decomposition took place in a cellar at 10 to 12 R., cholic 
 acid was deposited instead of choloidic, the higher temperature favouring the trans- 
 formation of cholic acid into its amorphous modification. 
 
 Human bile putrefies much in the same manner as ox-bile ; but the actual products 
 are usually modified by the decomposition of the albumin which is present in nearly all 
 the bile that can be obtained for examination, viz. the bile of persons who have died 
 of disease, and usually not obtained till some days after death. The alkaline products 
 resulting from the decomposition of the albumin partially neutralise the acid products 
 of the decomposition of the bile, and thereby prevent, to a certain extent, the formation 
 of insoluble compounds. (Thudichum.) 
 
 'Biliary calculi, or Gall-stones. These concretions in man sometimes consist chiefly 
 of chlolochrome, held together by some binding material, generally supposed to be 
 mucus, or inspissated bile, but consisting, according to Thudichum (loc. cit.), of cholic 
 or choloidic acid, or both. In most cases, a small nucleus of this character is formed, 
 and becomes coated with cholesterin, which then forms the chief mass of the concretion. 
 Earthy phosphates and carbonates are likewise present. Ox gall-stones consist mainly 
 of cholochrome, cholic acid, and choloidic acid, with small portions of cholesterin, and 
 unaltered bile mechanically enclosed : they also contain the phosphates and carbonates 
 of calcium and magnesium, and an ammonia-compound, possibly sulphide of ammo- 
 nium (Thudichum). The formation of these calculi is attributed by Thudichum to a 
 decomposition of the bile, similar to the putrefaction which takes place when it is re- 
 moved from the gall-bladder. (See G-ALL-STONES.) 
 
 BXMSTEZlf. See PUMICE-STONE. 
 
 BINARY THEORY OP SALTS. The theory which regards salts as com- 
 pounds of a metal with an acid or chlorous radicle : e. q. acetate of potassium 
 C 2 H 3 8 .K : nitrate of potassium, N0 3 .Z, &c. (See ACIDS.) 
 
 BZXrXJZTX:. A native sulpharsenite of lead, from the Binnenthal in the Valais, 
 where it is found imbedded in white granular dolomite. It sometimes forms distinct 
 prismatic crystals, belonging to the rhombic system, but more frequently, broad, reed- 
 like, crystalline aggregations, or crude masses : it is very brittle and friable. Colour, 
 steel-grey to iron-black, or light lead-grey, with strong metallic lustre. Opaque. Streak 
 reddish-brown. Hardness, 2'5 to 3-0. Specific gravity 5'0 to 5'5. Its composition 
 appears to be liable to some variation. According to Waltershausen, it is a mixture in 
 variable proportions of arsenomelane, Pb 2 S.As 2 S s , and scleroclase, 2Pb 2 S.As 2 S 3 . (Handw. 
 d. Chem. ii. [1] 1099.) 
 
 BZOTZ9T. Syn. with ANOKTHITB. 
 
 BZOTZTE. Uniaxial or Magnesia Mica. See MICA. 
 
 BZRCH. (Betula alba.) The bark of this tree contains, according to John (Re- 
 pert. Pharm. xxxiii. 327), one-third of its weight of resin, and a considerable quantity 
 of tannin, whence it is used for tanning leather, and for black-dyeing, especially of silk. 
 The white, easily separated epidermis of birch-bark, contains resin, tannic acid, ex- 
 tractive matter, and ash, consisting chiefly of sesquioxide of iron, silica, and lime. 
 The red-brown bark on the lower parts of the stem of an old tree, yields by successive 
 treatment with ether, alcohol, and aqueous potash, a resin, C 20 H 30 2 , soluble in ether, 
 a red-brown colouring matter, C 10 H 8 2 , soluble in alcohol, and another red-brown sub- 
 stance, C 20 H 18 9 , soluble in alkalis,- and precipitated by acids. (Stahelin and Hoch- 
 stetter, Ann. Ch. Pharm. li. 79.) 
 
 The leaves of the birch contain, according to Grossmann, 0'3 per cent, essential oil 
 and wax, besides tannin, and a bitter yellow colouring matter. They are used as fodder 
 in northern countries. 
 
 The dry wood of the birch contains, according to Karsten, 0'25 to 0-3 per cent, ash ; 
 according to Berthier 1-q per cent, Berthier found also in 100 pts. of the ash, 16 pts. 
 of soluble and 84 pts. of insoluble salts. Wittstein (Pharm. Centralb. 1851, p. 404), 
 has analysed the ash of birch-wood growing on different soils : viz. a. on the pala- 
 gonitic soil of Akareyri in Iceland, composed of weathered volcanic rocks ; o. on 
 the sterile calcareous soil of Morschen in Kurhessen, belonging to the Muschelkalk 
 
BIRCH BIRDLIME. 539 
 
 formation ; c. On the sandy soil of Marburg in Kurhessen, belonging to the sandstone 
 formation. 
 
 a b c a 
 
 K 2 . . 12-8 57 14-8 
 Na 2 . . 1-6 1*2 2-8 
 
 Ca 2 O 26-7 46-9 
 
 Mg*0 . . 2-2 1-7 11-8 
 
 A1 4 S . . 1-4 0-4 
 
 Fe 4 3 . . 0-8 0-4 
 
 Mn 4 3 trace 17 3 '8 
 
 SO 3 . . 0-02 
 
 SiO 2 . . 2'9 1-5 4-0 
 
 CO 2 . . 18-8 24-6 12-9 
 
 P 2 5 . . 8-1 4-2 16-6 
 
 H 2 . . 4-1 7-1 9-8 
 
 Charcoal . 0'6 0'4 0'5 
 
 Sand . 19-8 2-4 47 
 
 BIRCH-FUNGUS. The fungus of the birch-tree contains woody fibre, phoblaphene (a 
 substance also contained in pine-bark), fat, a bitter principle, uncrystallisable sugar, 
 tannin, malic acid, tartaric acid, and citric acid. It yields 15'3 per cent, water, and 
 1-2 per cent, ash, containing in 100 pts. : 5-0 K 2 ; 4'1 Na 2 ; 48-8 Ca 2 ; 5'5 Mg-O ; 
 3-1 A1 4 3 ; 1-6 Fe 4 3 ; 4-4 SO 3 ; 0-6 Cl; 15'6 P 2 5 ; 47 SiO 2 ; 15'9 CO 2 . (J. Wolff, 
 Vierteljahrschrift f. prakt. Pharm. iii. 1.) 
 
 BIRCH-JUICE. BIRCH- WATER. This liquid is obtained, like the juice of the maple, 
 by boring the stems of the trees in February and March. A tree of average size yields 
 about 8 litres of juice, consisting chiefly of sugar, together with nitrogenous substances 
 and various salts, including acid tartrate of potassium. It easily ferments, and quickly 
 turns sour when exposed to the air. In some localities, as in the Harz, in Courland, 
 and in Livonia, it is used for the preparation of an effervescent wine. 
 
 BIRCH-OIL. All parts of the birch-tree appear to contain an essential oil. The 
 young leaves and buds yield, by distillation with water, a colourless oil, which gradually 
 turns yellow in the air, has the aromatic odour of newly developed birch-leaves, and a 
 taste mild and sweetish at first, afterwards balsamic and burning. It is mobile at 
 14C., becomes viscid at 0, and solidifies to an amorphous mass at 10. It dis- 
 solves in alcohol more readily than in ether : water is said to extract a stearoptene (?) 
 from it. (G-rossmann, Repert. Pharm. xxiii. 327.) 
 
 The bark of the Betula lenta, a North American tree, yields an essential oil identical 
 with oil of wintergreen (salicylate of methyl) : it does not however exist in the bark 
 ready formed, but is produced from a crystalline substance, gauUherin, contained in the 
 bark, by the action of a ferment in presence of water, in the same way as bitter-almond 
 oil from amygdalin. (Procter, Amer. J. Pharm. Jan. 1844.) 
 
 BIRCH-RESEST. See BETULIN. 
 
 BIRCH- TAR. Dagged. Black Doggert or Deggelt. Birch-tar Oil. In Eussia and 
 other northern countries, the bark of the white birch is subjected to a kind of down- 
 ward distillation, in conical pits 20 or 25 feet deep, covered over first with a roofing 
 of straw, and then of turf and mould, having holes to regulate the admission of air, as in 
 the charcoal meilers. By this process, two products are obtained, namely, charcoal and 
 tar, the latter amounting to 60 or 70 per cent, of the bark. It is a brown-black viscid 
 liquid, used for coating wood, and also for lubricating carriage wheels, as it remains 
 liquid even at very low temperatures. 
 
 This tar when distilled yields a brown strong-smelling acid oil, and on rectifying 
 this oil, a liquid hydrocarbon, having the composition of oil of turpentine, passes over 
 at 100 C., mix'ed with an oxygenated oil, the proportion of the latter gradually in- 
 creasing as the distillation advances. The oxygenated oil may be removed by potash- 
 ley, and the hydrocarbon, C 10 H )fi , is left behind. Its smell is like that of oil of 
 turpentine, but more agreeable, recalling that of birch-bark. Specific gravity 0'S7 
 at 20 C. Boils at 156. Vapour-density 5'2 (calculation 2 vols. 4'8). At -16 it 
 deposits a small quantity of stearoptene. Sparingly soluble in water, readily in alcohol 
 and ether. It absorbs oxygen rapidly from the air, giving off carbonic anhydride, and 
 being converted into a resinous mass. It is also oxidised by nitric acid, giving off 
 hydrocyanic acid, and yielding two acid resins. It absorbs 32 per cent, chlorine, with- 
 out forming a crystalline compound. Betulin is perhaps formed from this hydrocarbon 
 by oxidation. (Sobrero, J. Pharm. [3] ii. 207.) 
 
 BIRDLIME. The best birdlime is made of the middle bark of the holly, boiled 
 seven or eight hours in water, till it is soft and tender ; then laid in heaps in pits in 
 the ground and covered with stones, the water being previously drained from it ; and 
 in this state left for two or three weeks to ferment, till it is reduced to a kind of muci- 
 lage. This being taken from the pit, is pounded in a mortar to a paste, washed in 
 river water, and kneaded, till it is free from extraneous matters. In this state it ife 
 left four or five days in earthen vessels, to ferment and purify itself, when it is fit for use. 
 
 It may likewise be obtained from the mistletoe, the Viburnum lantana, young shoots 
 of elder, and other vegetable substances. 
 
590 BISMUTH. 
 
 It is sometimes adulterated -with turpentine, oil, vinegar, and other matters. 
 Good birdlime is of a greenish colour, and sour flavour ; gluey, stringy, and tena- 
 cious, and in smell resembling linseed oil. By exposure to the air, it becomes dry and 
 brittle, so that it may be powdered; but its viscidity is restored by wetting. It 
 reddens tincture of litmus. Exposed to a gentle heat, it liquefies slightly, swells in 
 bubbles, becomes grumous, emits a smell resembling that of animal oils, grows brown, 
 but recovers its properties on cooling, if not heated too much. With a greater heat, it 
 burns, giving out a brisk flame and much smoke. The residue contains sulphate and 
 chloride of potassium, carbonate of calcium, and alumina, with a small portion of iron. 
 
 U. 
 
 BISMUTH. Symbol Bi. Atomic weight 208 (Schneider); 210 (Dumas). 
 The metal bismuth has long been known, but was formerly often confounded with tin 
 and lead. It is principally found in the metallic state, but also occurs in combina- 
 tion with sulphur, oxygen, and tellurium. In Cornwall and Cumberland it is found 
 associated with ores of cobalt, and in Siberia with lead, in the form of needle-ore or 
 bismuth-lead-ore. 
 
 For the arts it is prepared almost exclusively from native bismuth, and the great 
 source for it is Saxony, where it occurs in metallic veins in gneiss and clay-slate, accom- 
 panying ores of silver, copper, lead, and tin. 
 
 The process of extraction is very simple, the mineral being merely heated in close 
 vessels, so as to melt the bismuth, and thereby separate it from the gangue, or accom- 
 panying rock. The fusion is performed in iron tubes, laid in an inclined position, in 
 a furnace (fig. 100). The ore is introduced at the upper end, d, which is then plugged. 
 
 The other end, i, is closed with 
 an j ron pi a te having an aperture, o, 
 through which the melted metal 
 runs into earthen pots, , heated 
 by a few coals placed in the space, 
 K, below, so as to keep the metal 
 in the melted state. It is then 
 ladled out and run into moulds. 
 (See Ure's Dictionary of Arts, 
 Manufactures, and Mines, i. 304.) 
 As thus prepared, the metal is 
 impure, containing sulphur and 
 arsenic, copper, nickel, iron, and 
 other metals. It may be purified 
 by placing it in a crucible with 
 about its weight of nitre, and 
 keeping it melted at a temperature not too much above its point of fusion, the mixture 
 being continually stirred. The nitre, at first liquid, soon solidifies, forming with the 
 impurities a slag, which collects on the surface of the metal. By repeating this 
 operation a second time, the metal is obtained pure. 
 
 Small quantities of bismuth existing in lead-, copper-, and silver-ores, often become 
 concentrated in the secondary products of metallurgic operations, especially in the 
 process of separating silver from lead by cupellation. The lead oxidises faster than 
 the bismuth, so that towards the end of the operation a blackish litharge is obtained, 
 containing bismuth ; and by reducing this mixed oxide, and again expelling the re- 
 sulting alloy of lead and bismuth, the lead is oxidised and metallic bismuth remains. 
 (Jahresber. d. Chem. 1859, 711.) 
 
 To obtain chemically pure bismuth, the metal is dissolved in nitric acid ; and to the 
 clear solution, a large excess of water is added, which precipitates the bismuth as basic 
 nitrate, the other substances remaining in solution. The precipitate is well washed, 
 dried, mixed with black flux, and reduced at a gentle heat in a crucible, at the bottom 
 of which a regulus of pure metal is found. 
 
 Properties. Bismuth is a metal of a greyish-white colour, with a distinct roseate 
 tinge. When pure, it crystallises more readily than any other metal. It maybe obtained 
 in beautiful crystals by the following method. A few pounds are melted in a crucible, 
 and then poured into an earthen dish previously made hot. When the surface of the 
 metal has become covered with a crust, it is pierced on two opposite points with a rod 
 of red hot-iron, and the liquid metal allowed to run out. On afterwards carefully 
 removing the crust, the sides of the interior are found lined with beautiful crystals, 
 often in pyramidal cubes like the crystals of chloride of sodium. They possess an iri- 
 descent lustre, arising from a very thin film of oxide which has been formed on their 
 surface while still hot, and exhibits the colours of thin plates. Native bismuth crys- 
 tallises in cubes, and combinations of the cube with the octahedron ; also in regular 
 tetrahedrons, with cleavage very distinct, parallel to the faces of the octahedron (Kopp's 
 
BISMUTH. 591 
 
 Krystallographie). In Dana's Mineralogy (iii. 20), on the other hand, the crystalline 
 form is stated to belong to the hexagonal system. Bismuth appears therefore to be 
 dimorphous. Its specific gravity is 9'83, and it exhibits the singular anomaly, that 
 when it has been exposed to great pressure, its density becomes less. Pure bismuth 
 which has been exposed to a pressure of 200,000 pounds, was found to have the 
 specific gravity 9 - 556. It melts at 264 C., and expands about ^ in solidifying. 
 Hence its specific gravity is greater in the liquid than in the solid state. At a high 
 temperature, it may be distilled, and then sublimes in laminae. It is very brittle, 
 has a laminated, crystalline fracture, and is easily reduced to powder. Of all metals 
 it exhibits in the highest degree the phenomena of diamagnetism. 
 
 Exposed to dry or moist air, it does not alter, but when exposed in contact with water 
 in an open vessel, it becomes covered with a film of oxide of bismuth. Heated in the 
 air, it burns with a bluish flame, forming yellow fumes. It decomposes water at high 
 temperatures only. Concentrated hydrochloric acid acts on it with difficulty ; sul- 
 phuric acid attacks it only when hot and concentrated. Nitric acid briskly attacks it 
 and effects complete solution. 
 
 Bismuth forms three classes of compounds in which it is di- t tri-, and pent-atomic, 
 respectively. The tri-atomic compounds are the most stable and the most numerous, 
 e. g. BiCl 3 , Bil 3 , Bi 2 3 . Several di-atomic bismuth-compounds are also known, 
 viz. BiBr 2 , BiCl 2 , Bil 2 , Bi 2 0-, and Bi 2 S 2 . The only pent-atomic bismuth-compounds 
 hitherto obtained are the pent-oxide Bi 2 5 , together with the corresponding acid and 
 salts. E. A. 
 
 BISMUTH ACZCUZiAR. Plumbo-cupreous sulphide of bismuth. See NEEDLE- 
 ORE. 
 
 BISMUTH, AXiIiOTS OP. Bismuth unites readily with other metals, forming 
 easily fusible compounds. 
 
 A native arsenide of bismuth containing 3 per cent, of the latter metal, occurs at 
 Palmbaum, near Marienberg. It has a radiated texture like native sulphide of anti- 
 mony. Specific gravity 5'392. Hardness = 2 (Breithaupt). 14 pts. of bismuth 
 fused with 1 pt. of arsenic yield an alloy which expands strongly in solidifying. 
 
 Antimony unites in all proportions with bismnth, forming brittle alloys ; that which 
 contains equal parts of the two metals expands considerably in solidifying. 
 
 The most remarkable alloy of bismuth is that known as "fusible metal," which 
 consists of 1 pt. of lead, 1 of tin, and 2 of bismuth. It melts at 9375 C. Accord- 
 ing to Erman, it dilates in an anomalous manner when heated. It expands regu- 
 larly from 32 to 95 C., and then contracts gradually to 131 ; at which point it 
 occupies a less bulk than it did at 32; it then expands till it reaches 174, and from 
 that point its expansion is uniform. On account of this property of expanding as it 
 cools, while still in the soft state, it is much used for taking impression from dies, as 
 even the faintest lines are reproduced with minute accuracy. An alloy of bismuth 
 with potassium is obtained when bismuth is fused with cream of tartar, 5 pts. bismuth 
 to 4 pts. tartar. (For the other alloys of bismuth see the several metals.) E. A. 
 
 BISMUTH, BROMIDES OP. The tri-bromide, Bi"'Br 3 , is formed by heating 
 bismuth with excess of bromine. It is a steel-grey substance, like fused iodine ; melts 
 at 200 C., and boils at a dull red heat, with formation of hyacinth-red vapours. 
 Heated with metallic bismuth, it yields a brown crystalline mass, probably a di-bro- 
 mide BiBr 2 , but it has not been obtained pure. (Weber.) E. A. 
 
 BISMUTH, CHLORIDES OP. Trichloride, B"'C1 3 . Bismuth and chlorine 
 readily combine, with evolution of heat and light if the metal be finely divided. On 
 heating bismuth in a tubulated retort, in a current of chlorine, trichloride of bismuth 
 distils as a white easily fusible substance. It readily attracts moisture from the air, 
 becoming converted into a crystallised hydrate. The same substance is produced 
 when bismuth is dissolved in aqua-regia, and the excess of acid evaporated. Chloride 
 of bismuth dissolves in water containing hydrochloric acid ; by pure water it is de- 
 composed into hydrochloric acid, which dissolves a portion of the chloride, and a pre- 
 cipitate consisting of oxychloride of bismuth : 
 
 BiCl 3 + H 2 = BiCIO + 2HC1. 
 
 When a solution of nitrate of bismuth is poured into solution of common salt, a whif e 
 crystalline precipitate is formed, which is also oxychloride of bismuth, BiCl 3 .Bi 2 3 
 or BiCIO. It is used for paint, and is known as " pearl white." Chloride of bismuth 
 forms crystallisable double salts with the chlorides of potassium, of sodium, and of am- 
 monium. They are isomorphous with, and analogous in composition to, the correspond- 
 ing double chlorides of antimony. 
 
 BICHLORIDE OF BISMUTH, BiCl 2 , is produced by heating the trichloride with metal- 
 lie bismuth, also by the direct action of chlorine upon bismuth, provided the action 
 
592 BISMUTH. 
 
 be moderated by confining the current of chlorine to the upper part of the retort. 
 Partial reduction of the trichloride is likewise effected by phosphorus, zinc, tin, mer- 
 cury, and silver. The dichloride is a brown crystalline mass easily fusible and easily 
 decomposed by water or by a strong solution of sal-ammoniac. At a high tempera- 
 ture, it is resolved into metallic bismuth and trichloride. (K. "Weber, Pogg. Ann. 
 cvii. 596.) E. A. 
 
 BISMUTH CUPREOUS. See TANNENiTE and WITTICHITE. 
 
 BISMUTH, DETECTION" AND ESTIMATION OP. Blowpipe reac- 
 tions. All bismuth-salts, and likewise the sulphide, are easily reduced by mixing 
 them with carbonate of sodium, and heating the mixture on charcoal in the inner 
 blowpipe flame. A brittle bead of metallic bismuth is thereby produced, and a 
 lemon-yellow oxide, similar to lead-oxide, but darker, is deposited on the char- 
 coal around. This deposit disappears when heated in the reducing flame, without 
 colouring the outer flame, a character by which it is distinguished from lead. Oxide 
 of bismuth is easily reduced on charcoal without addition of soda. 
 
 In borax on platinum-wire, bismuth-oxide dissolves to a clear glass, yellow while 
 hot, and colourless when cold, if not supersaturated; in the latter case, yellowish- 
 red while hot, yellow when cold. In the inner flame on charcoal, the borax-glass 
 becomes grey and turbid, afterwards perfectly clear. The addition of tin makes it 
 grey at first, but after complete reduction, colourless and transparent. 
 
 In phosphorus-salt on platinum-wire, a small quantity of bismuth-oxide forms a 
 colourless glass ; with a large quantity, the glass is yellow while hot, colourless, or 
 sometimes enamel-white, on cooling. On charcoal, especially with addition of tin, 
 the glass is transparent and colourless while hot, but becomes blackish-grey and 
 opaque on cooling. (Berzelius and Plattner.) 
 
 Liquid Reactions. The salts of bismuth are mostly colourless. They have an 
 acid reaction, and their solutions when diluted with water, become milky, and yield a 
 white precipitate, consisting of an insoluble basic salt, while an acid salt remains in 
 solution. This reaction is best seen with the chloride, as the oxychloride formed is 
 almost absolutely insoluble. Iron, copper, lead, and tin, precipitate bismuth from its 
 solutions in the metallic state. Sulphydric acid and sulphide of ammonium throw 
 down a brown-black precipitate of trisulphide of bismuth, insoluble in excess of sul- 
 phide of ammonium. Caustic alkalis and their carbonates, phosphates, oxalates, and 
 tartratcs, throw down white precipitates, insoluble in excess of caustic potash or soda. 
 Chromate of potassium throws down a yellow precipitate of chromate of bismuth, 
 insoluble in caustic potash. Soluble sulphates produce no precipitate. This last 
 character, together with the insolubility of the precipitated chromate, hydrate, &c., 
 in caustic potash, distinguishes bismuth from lead. From antimony, which resembles 
 it in the decomposition of its salts by water, it is distinguished by its behaviour with 
 sulphydric acid, and by the insolublility of the basic salts thrown down by water, in 
 tartaric acid. 
 
 Quantitative Estimation. The best reagent for precipitating bismuth from 
 most of its solutions, is carbonate of ammonium, which, when added in excess, 
 throws down the bismuth completely, provided the liquid be left to stand for some 
 hours in a warm place. The precipitate, after being washed and dried, must be 
 separated from the filter as completely as possible, the filter separately burned, and 
 the precipitate ignited in a porcelain crucible ; a platinum crucible would be attacked 
 by it on ignition. It consists of trioxide of bismuth, Bi*0 3 , containing 89'66 per cent. 
 of the metal. 
 
 If the solution contains hydrochloric acid, the bismuth cannot be estimated by pre- 
 cipitation with carbonate of ammonium or any other alkali, because the precipitate so 
 formed would contain oxychloride of bismuth, and on igniting it, part of the bismuth 
 would be volatilised as chloride. In this case, therefore, the bismuth must be preci- 
 pitated by sulphydric acid, the sulphide of bismuth oxidised and dissolved by nitric 
 acid, and the diluted solution precipitated by carbonate of ammonium. 
 
 Atomic Weight of Bismuth. The first approximately correct determinations of 
 the atomic weight of bismuth were made in 1815 by Lagerjhelm (Ann. Ch. xciv. 
 161), who, from the proportion of bismuth in the sulphide Bi 2 S 3 , in the oxide Bi 2 3 , 
 and the sulphate Bi 2 (S0 4 ) 3 , estimated the atomic weight at 214'8, 212-8, and 212*3, 
 respectively. L. Gmelin (Handbook, iv. 428) found that these numbers were too 
 high, and that the oxide Bi 2 3 contained at least 10-33 per cent, oxygen ; whence 
 
 Bi 2 : O 3 = 89-67 : 10-33 ; and Bi = 89 ' 67 x 48 . = 2 Q8-2 at most. 
 
 2 x 10-33 
 
 This result was confirmed by Schneider in 1851 (Pogg. Ann. Ixxxii. 303). Pure 
 bismuth was oxidised by nitric acid in a flask (the small portions of metal carried oft 
 
BISMUTH. 593 
 
 by the vapours, being collected and allowed for), the solution evaporated, and the 
 residue gently ignited. Eight experiments thus made, showed that 100 pts. of tri- 
 oxide of bismuth, Bi 2 3 , contain from 10'318 to 10'366 pts. oxygen; mean = 10'345 : 
 
 whence Bi= x48 = 208-0. 
 
 Lastly, Dumas (Ann. Ch. Pharm. cxiii. 38), has determined the atomic weight of 
 bismuth by decomposing the trichloride Bid 3 (prepared by passing chlorine gas over 
 bismuth, and distilling till the product passed over is colourless), with excess of car- 
 bonate of sodium, and estimating the chlorine in the filtrate by means of a standard 
 silver- solution. Three experiments, with the purest portion of the distillate, gave 
 the numbers 209-88, 210*08, and 210'27. Dumas considers 210 to be the correct 
 number. 
 
 Separation of Bismuth from other Elements. From the non-metallic ele- 
 ments (excepting selenium}, and from the alkali-metals, bismuth is separated by carbo- 
 nate of ammonium; from the earth-metals, and from iron, cobalt, nickel, and the 
 other metals of the second group (p. 217), it is separated by sulphydric acid; from 
 tin, arsenic, antimony, and tellurium, by sulphide of ammonium ; and from copper and 
 cadmium, by ammonia. The separation of bismuth from cadmium may also be effected 
 by cyanide of potassium, which dissolves the latter as cyanide of cadmium and potas- 
 sium, and precipitates the bismuth. The precipitated bismuth, however, always 
 contains potash, and must therefore be dissolved in nitric acid, and precipitated by 
 carbonate of ammonium. Another mode of separating these two metals, given by 
 Lowe (J. pr. Chem. Ixvii. 464), is to heat the solution containing them with acid chro- 
 mate of potassium, which throws down the bismuth as Bi 2 3 .2Cr 2 3 , and retains the 
 cadmium in solution. 
 
 The separation of bismuth from lead cannot be effected by caustic potash, although 
 lead is soluble in that reagent, and bismuth insoluble ; for, when the metals are mixed 
 in solution, the oxide of lead precipitated by potash always carries some bismuth- 
 oxide down with it. The two metals may, however, be separated : 1. By sulphuric 
 acid. The acid is to be added in excess, the solution evaporated till the excess of 
 sulphuric acid begins to volatilise, and then diluted with water, whereupon the sulphate 
 of lead is left undissolved, while the sulphate of bismuth dissolves completely, pro- 
 vided sufficient excess of sulphuric acid is present. The sulphate of lead is then 
 collected on a filter, and washed with water containing sulphuric acid, and the bismuth 
 is precipitated from the filtrate by carbonate of ammonium, after the excess of acid 
 has been partly neutralised by ammonia. This method is not quite exact, because 
 sulphate of lead is not perfectly insoluble in acid liquids ; sulphuric acid, however, 
 dissolves less of it than any other acid. 2. Another mode of separating lead from 
 bismuth, is to dissolve the two metals or their oxides in nitric acid diluted with a very 
 small quantity of water, then add hydrochloric acid in sufficient quantity to convert 
 the metals into chlorides, and afterwards a considerable quantity of strong alcohol 
 mixed with a little ether. The chloride of bismuth is thereby held in solution, while 
 the chloride of lead is completely precipitated, and may be collected on a weighed 
 filter, and washed with alcohol containing ether. Lastly, the alcoholic solution of 
 chloride of bismuth is diluted with water, the alcohol evaporated, and the bismuth 
 precipitated by sulphuretted hydrogen. This method becomes more exact as the alcohol 
 used is stronger. 3. Ullgren separates bismuth from lead by precipitating the two 
 metals as carbonates, redissolving them in acetic acid, and immersing in the liquid a 
 weighed strip of clean sheet-lead, which must be completely covered by the liquid ; 
 the vessel is then closed and left to itself for several hours. The bismuth is thereby 
 precipitated as a metallic powder. It is rinsed off the surface of the lead, which is 
 then dried and weighed, and the precipitated bismuth is collected, dissolved in nitric 
 acid, and precipitated by carbonate of ammonium, or estimated by simply evaporating 
 the solution and igniting the residue. The lead in the solution is also precipitated by 
 carbonate of ammonium, and the carbonate of lead is converted into oxide by ignition, 
 and weighed, a deduction being made of the quantity of lead-oxide corresponding to the 
 lead which has been dissolved. 4. When lead and bismuth are mixed in the metallic 
 state, they may be separated by passing chlorine over the heated alloy, chloride of 
 bismuth then volatilising, while chloride of lead remains. Great care is, however, 
 required in regulating the heat, as too high a temperature would volatilise some of the 
 chloride of lead, and if the heat be too low, a portion of the chloride of bismuth will 
 remain. 
 
 For the separation of bismuth from mercury, silver, gold, platinum, and its allied 
 metals, see the several metals. 
 
 Valuation of Bismuth-ores. Ores containing only metallic bismuth, are 
 assayed by heating them in a crucible perforated at the bottom, and standing over a 
 VOL. I. Q Q 
 
594 BISMUTH. 
 
 receiver, into which the melted metal runs. The process is not quite exact, as a small 
 quantity of the metal remains mixed with the ore ; but it is sufficient for a check on 
 the results of the smelting on the large scale. If the ore likewise contains sulphide of 
 bismuth, it is ignited with two or three times its weight of black flux, sometimes with 
 addition of metallic iron, also of borax, if much earthy matter is present. If the ore 
 also contains other metals, which are reduced together with the bismuth, the metallic 
 button must be dissolved, and the several metals separated by analysis in the wet 
 way, as above described. (Kerl, Hiittenkunde, ii. 355.) 
 
 BXSXVTUTH, FLUORIDE OP. Soluble in water and deposited as a white powder, 
 when the aqueous solution is evaporated. (Berzelius.) 
 
 BISMUTH, IODIDE OP. BiP. Obtained by mixing 1 at. of trisulphide of 
 bismuth (which has been prepared by precipitation) with 3 at. of iodine, and gently 
 heating the mixture in a capacious loosely covered glass globe, on the sides of which 
 the compound condenses. The iodine simply takes the place of the sulphur (Schnei- 
 d e r.) It is likewise produced by throwing iodine in small portions into a tube in 
 which bismuth is strongly heated, and distilling out of contact with the air (Weber). 
 It forms large brilliant grey hexagonal tables, which, according to Nickles 
 (Compt. rend. 1. 872) are isomorphous with the tri-iodides of arsenic and antimony. 
 Metallic bismuth decomposes it in the same manner as the tribromide. (Weber). 
 
 An oxyiodide of bismuth, BilO, is formed when the tri-iodide is heated for some time 
 in a crucible, and collects below the crystallised iodide thus obtained, in a mass of 
 copper-coloured rhombic laminae. In a close vessel, it may be partially volatilised 
 without alteration, but when strongly heated in contact with the air, it is converted 
 into oxide. It is not decomposed by water or by alkaline solutions ; hydrochloric 
 acid dissolves it without alteration ; nitric acid decomposes it, with separation of iodine. 
 (Schneider, J. pr. Chem. Ixxix. 424.) 
 
 A sulphiodide, BilS, is obtained by adding to melted iodide of bismuth, as much 
 sulphur as it is capable of dissolving ; it is likewise produced in the preparation of the 
 tri-iodide by Schneider's method, and collects at the bottom of the vessel, together 
 with a small quantity of the iodide, in small, shining, steel-grey needles. It appears 
 to have the same form as the trisulphide. (Schneider, J. pr. Chem. Ixxix. 422.) 
 
 E. A. 
 
 BISMUTH, OXIDES OP. Bismuth forms two .definite compounds with oxygen, 
 Bismuthous oxide or trioxide of bismuth, Bi 2 3 , and bismuthic oxide or anhydrid^, 
 Bi 2 5 . An intermediate oxide, Bi 2 4 , is known, but it may be regarded as a compound 
 of the other two a bismuthate of bismuth, Bi 2 3 . Bi 2 5 . A dioxide, Bi 2 2 , appears also 
 to exist ; it is formed when a solution of a bismuth-salt is treated with protochloride 
 of tin. A corresponding sulphide is known. 
 
 BISMUTHOUS OXIDE, or TBIOXIDE OF BISMUTH, Bi 2 3 , is formed when the metal is 
 roasted in air, but is best obtained by gently igniting the subnitrate. It is a pale yellow 
 powder, which melts at a red heat, and solidifies on cooling to a glass having a deeper 
 yellow tint. It occurs native, as bismuth-ochre, associated with iron and some other 
 impurities (Bi 2 3 86-4 per cent.; Fe 4 3 5-1 ; CO 2 4*1 ; water 3-4), at Schneeberg in 
 Saxony, at Joachimsthal in Bohemia, and with native gold at Beresof in Siberia. 
 (Dana, ii. 141.) 
 
 The hydrated oxide of bismuth, BiHO 3 . or Bi 2 3 H 2 0, is obtained as a white precipi- 
 tate when a solution of subnitrate of bismuth is decomposed by an alkali. If the 
 hydrate be boiled with potash, it loses water, and is changed into a yellow crystalline 
 powder which is the anhydrous oxide. 
 
 The hydrate is occasionally used in analysis for converting into oxides certain 
 metallic sulphides soluble in alkalis. For this purpose, the alkaline solutions are boiled 
 with the hydrated oxide. 
 
 Both the hydrate and the anhydrous oxide dissolve in the stronger acids, forming 
 the normal bismuth salts, which have the composition Bi'"A 3 , the symbol A denot- 
 ing an acid radicle, e. g. : 
 
 BiCl 3 ; Bi(NO) 3 = '0 3 ; Bi 2 (S0 4 ) 3 = 0, &c. 
 
 Many of these salts crystallise well, but cannot exist in solution unless an excess of 
 acid is present. On diluting the solutions with water, a basic salt is precipitated, and 
 an acid salt remains in solution. 
 
 BISMUTHIC OXIDE or ANHYDRIDE, Bi 2 5 ; in combination : BISMUTHIC ACID. Pre- 
 pared by passing chlorine through a concentrated solution of potash which contains 
 hydrated trioxide of bismuth in suspension. A blood-red substance then separates, 
 which is a mixture of hydrated bismuthic acid, and trioxide of bismuth. This is treated 
 
BISMUTH. 595 
 
 with dilute nitric acid, which dissolves the oxide, but, in the cold, does not attack the 
 acid. 
 
 Bismuthic oxide is a bright red powder, which loses part of its oxygen at a tempera- 
 ture little above 100 C. and becomes converted into the intermediate oxide, Bi 2 4 , 
 bismuthate of bismuth. Acids also decompose it, reducing it to the state of bismuthous 
 oxide, which then combines with the acid. 
 
 The bismuth at es are little known, and of no importance; according to Arppe, 
 bismuthic acid forms with potash, a salt which is an acid bismuthate of potassium : 
 Bi-KHO 6 = BiK0 3 .BiH0 3 . E. A. 
 
 BISMUTH, OXVCHIiORIBE OF. (p. 591.) 
 
 BISMUTH OXYGE3NT-SALTS OF. See the several acids. 
 
 BISMUTH, PHOSPHIDE OF. Melted bismuth takes up a small quantity of 
 phosphorus, being thereby rendered more brittle and less laminar. Phosphoretted 
 hydrogen gas throws down from solution of nitrate of bismuth a black phosphide of 
 the metal, which gives off all its phosphorus by distillation. (Berzelius.) 
 
 BISMUTH, SELENIUE OF. Bismuth and selenium unite when heated toge- 
 ther with faint evolution of light and heat, and form a silver-white mass, having a 
 crystalline fracture, and fusing at a red heat : the fused mass has a specular surface. 
 (Berzelius.) 
 
 BISMUTH, SULPHIDES OF. Bismuth readily unites with sulphur. When 
 the two substances in fine powder are fused together, they combine, with disengage- 
 ment of heat. Two distinct compounds are known. 
 
 BISULPHIDE OF BISMUTH, Bi"S. According to Wertheim, it is obtained crystallised 
 by melting together bismuth and trisulphide of bismuth in equivalent quantities. The 
 mixture is then allowed to cool slowly, on which the sulphide crystallises from the 
 liquid metal, which may be poured off from the crystals. More recently it has been 
 shown that these crystals, although giving by analysis numbers corresponding to BiS, 
 are really a compound of trisulphide of bismuth with metallic bismuth. According to 
 Schneider, disulphide of bismuth may be prepared in the moist way, by mixing an 
 alkaline solution of bismuthous oxide with an alkaline solution of stannous oxide, and 
 precipitating with sulphuretted hydrogen. The tin remains dissolved, and a black pre- 
 cipitate is formed, which, when washed and dried in the water-bath, is found to have the 
 composition BiS.H 2 0. It is a black lustreless powder, which, under the burnisher, takes 
 the form of black laminae. 
 
 TRISULPHIDE OF BISMUTH, Bi 2 S 3 , occurs native as bismuth-glance, or bismttthine, in 
 Cumberland and Cornwall, also in Saxony, at Bastnas in Sweden, and according to 
 Shepard, at Haddam in Connecticut, associated with chrysoberyl. It crystallises in aci- 
 cular prisms of the trirnetric system, isomorphous with native sulphide of antimony. 
 oo P . oo P oo .00 Poo . oo P 3 . oP. Inclination of oo P : oo P = 91 30'. Cleavage 
 perfect parallel to oP and oo P oo ; less perfect parallel to co P oo . It occurs also 
 massive, with foliated or fibrous structure. Specific gravity 6*4 to 6*55. Hardness 
 = 2 to 2-5. Opaque, with metallic lustre, lead-grey colour and streak. Sectile. 
 (Dana, ii. 33.) 
 
 The same compound is prepared in the dry way, by fusing pulverised bismuth with 
 one-third of its weight of sulphur, and removing the excess of sulphur by a second 
 fusion. A laminated mass is thus obtained, composed of crystals having the same form 
 as the native sulphide. According to Marx, it expands to the amount of one-fourth its 
 volume in solidifying. The trisulphide is also obtained as a brown-black precipitate, 
 when sulphydric acid gas is passed into the solution of a bismuth-salt. E. A. 
 
 BISMUTH, SULPHOCHLORIDE OF. BiSCl, or BiCP.Bi'S 3 . This com- 
 pound is best obtained by gradually adding pulverised trisulphide of bismuth to 
 melted ammonio-bismuthous chloride (2NH 4 Cl.BiCl 3 ), and washing the resulting mass 
 with water acidulated with hydrochloric acid. It is also formed by heating the same 
 double chloride with sulphur, or in sulphydric acid gas. It forms small, metallic- 
 shining, blue-grey crystalline needles, which yield a red powder. Heated in carbonic 
 acid gas, it gives off chloride of bismuth and leaves the sulphide ; heated in hydrogen, 
 it gives off hydrochloric and sulphydric acids, and leaves bismuth. It is decomposed 
 by strong hydrochloric and strong nitric acid ; also by alkalis, which remove the chlo- 
 rine and leave an oxysulphide. (E. Schneider, Pogg. Ann. xciii. 464.) 
 
 BISMUTH, TELLURIC. Bi 2 STe. See TELLUKIUM. 
 
 BISMUTH, TELLURIDE OF, The two metals unite in all proportions by 
 fusion. 
 
 BISMUTH-BIiEZTBE. Native silicate of bismuth. See SILICATES. 
 
 BISMUTH-GLANCE, or BISMUTHIVTE. Native trisulphide of bismuth 
 (see above). 
 
 Q Q 2 
 
596 BISMUTH-RADICLES, ORGANIC. 
 
 BlSlVTUTH-NICKEli. Grunauite. Saynite. A sulphide of bismuth and nickel, 
 found, together with quartz and copper pyrites, at Griinau in Sayn Altenkirchen, 
 crystallised in regular octahedrons, sometimes perfect, sometimes having the summits 
 more or less replaced by faces of the cube. Cleavage octahedral. Specific gravity 
 5'13. Hardness 4-5. Colour, light steel-grey to silver- white, often yellowish or greyish 
 from tarnish. Its composition in 100 parts is given by the following analyses : 
 S Bi Ni Fe Co Cu Pb 
 
 38-46 14-11 40-65 3-48 0'28 1'68 1'58 Kobell. 
 
 31-99 10-49 22-03 6*55 11-24 11'59 7'11 Schnabel. 
 
 33-10 10-41 22-78 6-06 1173 11-56 4-36 
 
 Before the blowpipe it melts to a grey, brittle, magnetic globule, colouring the char- 
 coal greenish-yellow. Dissolves in nitric acid, excepting the sulphur. (Dana, ii. 44.) 
 
 BISMUTH-OCHRE. Native trioxide of bismuth (p. 594). 
 
 BlSIMUTH-R/V-DICIiES, ORGANIC. The only compounds of this class as 
 yet obtained, are the Bismuthides of Ethyl, viz. Bistriethyl, discovered by Lowig 
 and Schweizer (Ann. Ch. Pharm. Ixxv. 355), and further examined by Breed (ibid. 
 Ixxxii. 106), and Bisethyl, discovered by Diinhaupt in 1854 (ibid. xcii. 372). 
 
 BISETHTL. _ C 2 H 5 Bi. The chloride of this radicle, C 2 H 5 BiCl 2 (?) is obtained, together 
 with a precipitate of chloride of hydrargethyl, by the action of bistriethyl on chloride 
 of mercury (p. 596). The chloride of bisethyl remains in solution and may be obtained 
 by spontaneous evaporation in crystals, which however do not dissolve completely in 
 water, but leave a white powder. On adding iodide of potassium to the aqueous solu- 
 tion, then diluting with water till turbidity is produced, boiling till the solution be- 
 comes clear, and leaving it to cool, iodide of bisethyl separates in yellow six-sided 
 laminae, which appear to have the composition C 2 H 5 BiI 2 . A solution of this compound 
 in hydrated alcohol treated with ammonia, forms a yellowish- white precipitate of the 
 kydrated oxide, which, after drying in vaeuo, ignites spontaneously in the air, giving off 
 a dense yellow vapour. The oxide appears also to be formed by the spontaneous 
 oxidation of bistriethyl, 2 atoms of ethyl being eliminated. Sulphide of bisethyl is 
 formed by treating the iodide with sulphydric acid ; and the nitrate and sulphate 
 by acting on the iodide with the corresponding silver-salts. (Diinhaupt.) 
 
 BISTRIETHYL, or TEIETHYL-BISMUTHINE. (C 2 H 5 ) 8 Bi. Bismethyl. Formed by the 
 action of iodide of ethyl on bismuthide of potassium. 
 
 Preparation. Bismuthide of potassium, finely pounded, and without admixture of 
 sand, is introduced into a small flask ; iodide of ethyl added in excess ; the flask closed, 
 and immediately connected with a long narrow distillation-tube passing into a receiver 
 surrounded with ice, all these manipulations being performed as quickly as possible. 
 In a few minutes, the action begins, the mixture becomes heated, and the excess of 
 iodide of ethyl distils over. Water free from air is then introduced into the flask, 
 which is immediately closed and heated in the water-bath, till the mass becomes soft 
 and the iodide of potassium is dissolved. The same operations are repeated with a 
 considerable number of flasks ; the disintegrated contents transferred as quickly as 
 possible into a large flask filled with carbonic anhydride ; shaken up several times with 
 a large quantity of ether ; the ethereal solution mixed with the de-aerated water ; and 
 the ether completely distilled off in the water-bath. The bistriethyl remains at the 
 bottom of the water, and is purified by distilling it with water (it cannot be distilled 
 alone, without decomposition), shaking it up with a small quantity of dilute nitric acid 
 to free it from oxide, and drying over chloride of calcium. During all these operations, 
 the air must be carefully excluded (Breed). 3 Ibs. of bismuthide of potassium and 
 1 Ib. of iodide of ethyl, yield 4 or 5 oz. of pure bistriethyl. (Diinhaupt.) 
 
 Properties. Transparent, very mobile liquid, sometimes colourless, but often slightly 
 tinged with yellow. Has an unpleasant odour like that of stibtriethyl, and its vapour, 
 when inhaled, even in small quantity, produces a very disagreeable burning sensation 
 on the tip of the tongue (Breed). Insoluble in water, sparingly soluble in ether, 
 readily in absolute alcohol. 
 
 ^ Decompositions. 1. Bistriethyl heated in a retort, begins to boil at about 50 C., 
 giving off a gas free from bismuth, which burns with a clear flame, while metallic bis- 
 muth separates out in the retort. If the heat be continued, the thermometer rises 
 above 160 C., and continues to rise till a sudden and violent explosion takes place, 
 which shatters the apparatus (Breed). The dilute ethereal solution is also decomposed 
 when left to evaporate in the air, leaving a white residue of hydrated oxide of bismuth 
 (Diinhaupt). 2. Bistriethyl exposed to the air, gives off thick yellow vapours and 
 takes fire with slight explosion, diffusing a dense yellow smoke of bismuth-oxide ; this 
 effect is best shown by moistening a piece of filtering paper with the liquid and ex- 
 posing it to the air. 3. Fuming nitric acid decomposes bistriethyl, with explosion and 
 
BISMUTH-SILVER BITTER-ALMOND OIL. 597 
 
 vivid combustion. 4. Bistriethyl burns in chlorine gas with separation of charcoal, 
 and takes fire in contact with bromine. In general, its reactions resemble those of 
 stibtriethyl (Breed). 5. Bistriethyl added to solutions of metallic salts (e.g. to 
 nitrate of silver or corrosive sublimate), does not simply throw down the oxide, but is 
 itself decomposed. On adding an alcoholic solution of bistriethyl to a not too dilute 
 solution of protochloride of mercury, the former being poured slowly and with constant 
 stirring into the latter, a very large precipitate of mercurous chloride is immediately 
 obtained, chloride of bismuth and hydrochloric ether being doubtless formed at the 
 same time. But if the process be reversed, and a hot dilute alcoholic solution of cor- 
 rosive sublimate be poured in a thin stream and with constant stirring into a dilute 
 alcoholic solution of bistriethyl to which a few drops of hydrochloric acid have been 
 added, to prevent separation of oxide of bismuth, no precipitate is formed at first ; but 
 after some time, a bulky precipitate appears, which however is again completely dis- 
 solved if the liquid be heated. The reaction is terminated when a drop of the liquid 
 no longer produces a white precipitate in a solution of corrosive sublimate ; by a little 
 care, it may be arranged that neither liquid shall predominate. If the liquid be then 
 heated on the water-bath till it becomes perfectly clear, separated, if necessary, from a 
 small quantity of metallic mercury by decantation, and then left to cool, light, crys- 
 talline, silvery, iridescent laminae separate out and gradually fill the whole fluid. These 
 crystals consist of chloride of hydrargethyl, C 2 H 5 Hg 2 Cl ; the solution from which they 
 are deposited contains chloride of bisethyl, C 2 H 5 BiCl 2 (Dun haupt) : 
 
 (C 2 H 5 ) 8 Bi + 4HgCl = 2C 2 H 5 Hg 2 Cl + C 2 H 5 BiCl 2 . 
 
 Combinations. Bistriethyl combines with Bromine, Iodine, Sulphur, &c. ; but the 
 compounds are less stable than those of stibtriethyl. 
 
 Bromide of Bistriethyl appears to be formed when bromine is added to an alcoholic 
 solution of bistriethyl ; but the solution deposits bismuth when evaporated. 
 
 Iodide of Bistriethyl. When iodine is added to an alcoholic solution of bistriethyl, 
 heat is evolved, the colour of the iodine disappears, and iodide of bistriethyl is formed. 
 This compound is less stable than iodide of stibtriethyl; when its alcoholic solution is 
 left to itself for a while, iodide of bismuth separates out. (Breed.) 
 
 An iodide having the composition C 6 H 15 Bi 3 ! 5 , or (C 2 H 5 ) 3 BiI 2 .Bi 2 ! 3 , is obtained by 
 adding iodine to a tolerably strong alcoholic solution of bistriethyl, till its coiour [no 
 longer ?] disappears, filtering from the precipitate, and adding to the filtrate a large 
 qtiantity of water at 40 C. A small quantity of a ruby-coloured liquid separates ; and 
 if the watery liquid be poured off from this, a large quantity of beautiful red needle- 
 shaped crystals are formed as it cools ; these must be immediately collected and dried 
 in vacuo. The same compound is formed when bistriethyl is left for .a considerable 
 time in contact with dilute nitric acid and then mixed with iodide of potassium. It is 
 sparingly soluble in water, but dissolves pretty readily in alcohol and ether ; the solu- 
 tions have a pale yellow colour. The compound heated on platinum foil gives off 
 a strong yellow vapour which takes fire on coming in contact with flame. (Diin- 
 haupt.) 
 
 Another iodine-compound, having the formula (C 2 H 5 ) 4 Bi.2C 2 H 5 I, is contained in the 
 above-mentioned ruby-coloured liquid ; but it is very instable. (Diinhaupt.) 
 
 Sulphide of Bistriethyl, has not been obtained in the separate state. Bistriethyl 
 which has been long exposed to the air under water, gives with sulphuretted hydro- 
 gen, first a yellow, then a brown precipitate, consisting of (C 2 H 5 ) 3 BiS.Bi 2 S 3 . (Diin- 
 haupt.) 
 
 BISAXITTH-SXIiVER. A mineral sometimes occurring in acicular or capillary 
 crystallisations, but more generally amorphous, as at Schapbach in Baden ; it is found 
 also in the cupreous shale of Mansfeld, Thuringia. It is soft and sectile, opaque, with 
 metallic lustre and tin-white or greyish colour, subject to tarnish ; fracture uneven. 
 Contains, according to Klaproth's analysis, 27 per cent, bismuth, 33 lead, 15 silver, 
 4'3 iron, 0-9 copper, and 16'3 sulphur. A bismuth-silver from the mine of San Antonio 
 near Copaipo, Chili, was found by Domeyko to contain 60'1 per cent, silver, lO'l bis- 
 muth, 7 '8 copper, 2 -8 arsenic, and 19-2 gangue. It occurs disseminated, and has one 
 or more imperfect cleavages, and is probably either monometric or rhombohedral 
 (Dana, ii. 16.) 
 
 BZS1VITJTITE. Native carbonate of bismuth. See CAEBONATES. 
 BXSSA-BOXi. A gum resin from Arabia, resembling mvrrh. (Vauehan 
 Pharm. J. Trans, xii. 227.) 
 
 BISTRE, A brown pigment, consisting of the finer parts of wood-soot, separated 
 from the grosser by washing. The soot of beech- wood is said to yield the best bistre. 
 (See Ure's Dictionary of Arts, Manufactures, and Mines, i. 307.) 
 
 Oil,. A peculiar volatile oil obtained by distilling bitter- 
 Q Q 3 
 
598 BITTER-ALMOND OIL. 
 
 almonds with water. It was discovered by Martres in 1803 ; Stange showed that the 
 crystallised acid which is produced from it is benzoic acid ; Robiquet, and Lie-big and 
 Wohler explained its formation ; and Liebig and Wohler (1832, Ann. Ch. Pharm. 
 xxii. 1) first fully examined it. It is also obtained from the amygdaliferous parts of 
 most PomcfS and Amygdalece ; from the leaves of the cherry-laxirel ( Ccrasus lauro- 
 cerasus'), and of CL rasus padus, from peach and cherry -kernels, &c. It is possible 
 that many of these oils are not identical, but isomeric, with bitter-almond oil, and that 
 it is owing to their presence that different specimens of the commercial oil yield with 
 the same reagent such different results. The chief constituent of the oil is hydride of 
 benzoyl, always accompanied by hydrocyanic acid and other compounds (see BENZOYL, 
 HYDEIDE or). The oil does not exist ready-formed in bitter-almonds, but is produced 
 by the action of water and a peculiar ferment, emulsin or synaptase, upon the 
 amygdalin contained in the almonds, which is thereby converted into hydride of ben- 
 zoyl, hydrocyanic acid, and glucose : 
 
 C' ; H 27 N0 11 + 2H 2 = C 7 H 6 + CNH + 2C 6 H 12 6 . 
 
 Amygdalin. Hydride Glucose, 
 
 of benzoyl. 
 
 The oil is thus prepared : Bitter- almonds are crushed, and freed from fixed oil by 
 cold pressing, then stirred up to a thin paste with 4 6 pts. cold or lukewarm water, 
 and the mixture allowed to stand for twenty-four hours before distillation. If dis- 
 tilled over the open fire, it is very apt to froth over, unless it is stirred continually ; 
 for this reason it is best distilled with vapour of water. This maybe done by covering 
 the bottom of the still with a thick layer of coarse sand saturated with water, and 
 pouring the almond-paste upon it. The frothing may also be avoided by removing 
 most of the solid matter before distilling. The first portion of the distillate is richest in 
 oil, and in hydrocyanic acid also, and is therefore clear; the latter portions, containing 
 less hydrocyanic acid, are milky. The distillation is continued as long as the liquid 
 which comes over smells of bitter-almonds ; the oil in the receiver is then separated 
 from the water, which, as it contains a good deal of oil in solution, is again distilled, 
 when the oil passes over with the first portions of the water. The addition of chloride 
 of sodium facilitates the separation of the oil. 1000 pts. almonds do not yield more 
 than 7 or 8 pts. oil. 
 
 Bitter-almond oil is colourless when freshly prepared, but soon becomes yellow ; it 
 has a peculiar strong aromatic smell, besides that of prussic acid, and a burning taste ; 
 is heavier than water; boils at about 180 C., and burns with a smoky flame. Its poi- 
 sonous action is entirely owing to the presence of prussic acid. (For methods of puri- 
 fying the oil, see BENZOYL, HYDRIDE OF.) 
 
 Bitter- almond oil was formerly much used in perfumery, but it is now replaced in 
 great measure by nitrobenzene (essence de Mirbane). Being an expensive article, it is 
 very liable to adulteration, usually with alcohol (which, if added in moderation, does 
 not materially affect its smell), light ethereal oils, or nitrobenzene. Light oils, whose 
 smell is masked by that of hydride of benzoyl, may be detected by allowing the latter 
 to oxidise into benzoic acid by exposure to the air, when the smell of the former be- 
 comes evident, or by their effect on the specific gravity of the oil, a method which 
 applies to alcohol also. Alcohol may also be detected by agitating the oil with twice 
 its volume of nitric acid of specific gravity T42 ; with unadulterated oil, no immediate 
 action is produced ; but, if 8 10 per cent, alcohol be present, red fumes are given off 
 with effervescence. By using acid of 1-5 specific gravity, as little as 3 4 per cent, 
 alcohol may be detected (Redwood). A good reagent for detecting adulterations is 
 a strong solution of an acid sulphite of alkali-metal, which dissolves the pure oil entirely, 
 but leaves behind all impurities which are not of the nature of aldehydes. 
 
 Owing principally to the presence of hydrocyanic acid, bitter-almond oil behaves 
 with several reagents differently from hydride of benzoyl. By heat and by oxidising 
 agents generally, e.g. by nitric acid, it is acted on in the same manner as hydride of 
 benzoyl. With sulphuric acid, it yields stilbous acid, and (perhaps) benzoate of hy- 
 dride of benzoyl. A mixture of Nordhausen sulphuric acid with bitter-almond oil 
 yields, on addition of water, a crystalline body, which presents the properties of man- 
 delic acid. Dry chlorine acts upon it as upon hydride of benzoyl ; with moist chlorine 
 it forms stilbesic acid and benzoate of hydride of benzoyl. To this latter compound, 
 which is frequently regarded as identical with stilbous acid, Liebig assigns the for- 
 mula C 21 H 18 0' = 2C 7 H 6 O + C 7 H 6 2 . Bitter-almond oil saturated with moist chlorine 
 solidifies finally to a crystalline mass, which, when washed with cold ether, leaves this 
 compound as a crystalline powder. It is insoluble in water, slightly soluble in cold 
 ether, abundantly in alcohol. When heated, it melts and volatilises un decomposed . 
 Heated with alcoholic potash, it yields potassic benzoate. With hydrochloric acid, it: 
 yields either hydrocyanate of hydride of benzoyl or mandelic acid. With chloride of 
 
BITTER- ALMOND WATER BITTER SPAR. 599 
 
 sulphur, it yields stilbous acid. With sulphide of ammonium, it yields hydride of 
 thiobenzoyl,* hydride of sulphozobenzoyl, and sulphydrate of azobenzoyl. With bi- 
 sulpliide of carbon and ammonia, it yields sulphocyanobenzylene. With cyanide of 
 potassium, it yields sometimes benzoin, sometimes benzamide. Solid potash converts 
 it into benzoic acid ; aqueous or alcoholic potash (especially the latter) into benzoin. 
 With ammonia, it yields very various products, according to circumstances ; these are azo- 
 benzoide, azobenzoidin, azobenzoyl, benzamil, benzhydramide, benzoylazotide, diben- 
 zoylimide, hydrobenzamide, stilbazide. Most of these compounds were discovered by 
 Laurent, and many are very imperfectly known. Baryta- or lime-water converts it 
 into benzoin. F. T. C. 
 
 BXTTER-AXiftlOND WATER. A pharmaceutical preparation, employed in 
 medicine, consisting of a solution of bitter-almond oil in water. It is prepared in the 
 same manner as bitter-almond oil ; but, since the water must be of a known strength, 
 the quantity of almonds and water to be employed and of distillate to be collected is 
 fixed by the pharmacopoeia. These quantities vary in different pharmacopoeias : in the 
 Prussian, 2 Ibs. almonds are pressed and macerated with 10 Ibs. water, 4 ozs. alcohol 
 added, and 2 Ibs. of distillate collected. The Parisian pharmacopoeia collects 2 Ibs. 
 the Saxon 3 Ibs. of distillate for each pound of almonds. The addition of alcohol does 
 not seem to have any advantage. Heat must be carefully avoided in the pressure and 
 maceration of the almonds. Bitter-almond water is generally a more or less milky liquid, 
 smelling and tasting strongly of crude bitter-almond oil ; it decomposes by exposure to the 
 air, and must therefore be kept in stoppered bottles completely full. Its strength is very 
 uncertain, however closely the pharmacopoeia directions are adhered to. It is usually 
 valued by the amount of prussic acid which it contains, which may be readily deter- 
 mined by Liebig's volumetric method (see HYDROCYANIC ACID, under CYANOGEN) ; the 
 Prussian pharmacopoeia requires it to contain - 14 per cent, prussic acid Laurel-water, 
 prepared from laurel leaves, and cherry-water from wild cherries, contain the same 
 constituents as bitter-almond water. The latter may be distinguished from laurel- 
 water by becoming milky immediately on addition of ammonia, an effect which is 
 not produced on laurel-water till after some time ; or, according to Lepage, by chloride 
 of gold, which gives with both waters a yellow colour, which, in bitter-almond water, 
 disappears in eight hours, while in laurel- water it remains for twenty-four hours. (J. 
 Ch. med. xxiv. 365.) F. T. C. 
 
 BITTER PRINCIPLE. Many vegetable substances yield bitter extracts, which 
 were formerly supposed to contain a common constituent, called Principium amarum. 
 More exact investigation having shown, however, that many of these vegetable bitters 
 are definite chemical compounds of very various composition, e.g. picric acid and the 
 vegetable alkaloids, the term bitter principle is now restricted to the brown amor- 
 phous bitter extractive matter obtained from many plants by boiling with water, 
 evaporating the extract to dryness, exhausting with hydrated alcohol, evaporating, and 
 treating the residue with absolute alcohol, which dissolves resins, &c., and leaves the 
 bitter substance undissolved. The products thus obtained, are not, generally speaking, 
 of definite constitution. From some plants, however, more definite bitter principles 
 are obtained, e. g. asbinthin from wormwood, aloin from aloes, &c. 
 
 BITTERN. The mother-water which remains after the crystallisation of common 
 salt from sea-water or the water of salt-springs. It contains a considerable quantity 
 of sulphate and chloride of magnesium, to which its bitterness is owing, also more or 
 less bromine and iodine. 
 
 BITTER SPAR or RHOMBSPAR. Brown-spar. Pearl-spar. Talc-spar. 
 Dolomite. Chaux carbonatee magnesifere. This mineral crystallises in rhombohedrons, 
 which were formerly confounded with those of calcspar, but differ in the angles, the 
 primary form being an acute rhombohedron of 106 18', and 73 42' (mean). The 
 crystals are generally rhombohedrons E, with more acute or more obtuse rhombohedron 
 in combination, the base OR and the hexagonal prisms ooR often occurring. The 
 rhomb K generally has its faces curved like a saddle ; R is more generally lenticular. 
 Cleavage parallel to R. Fracture conchoi'dal, uneven, splintery, and earthy. Colour 
 white, greyish, or yellow, with a somewhat pearly lustre. Rarely transparent, but ex- 
 hibits various degrees of translucence down to complete opacity. Hardness 3 '5 to 4'5. 
 Specific gravity 2'8 to 3'0. Its formula is (Ca 2 ; Mg*)C0 3 , the calcium and magnesium 
 replacing one another in any proportion, so that it presents all varieties of composition, 
 from that o# calcspar to that of magnesite. Iron (ferrosum) and manganese (manga- 
 nosu?)i) also occur, replacing the other metals in subordinate proportions. In the state 
 of powder, it dissolves readily in warm hydrochloric acid, but in lumps the acid scarcely 
 acts upon it. Before the blowpipe, it becomes caustic, but does not melt. It is 
 usually imbedded in serpentine, chlorite, or steatite, arid is found in the Tyrol, Salz- 
 
 Q Q 4 
 
600 BITTERSWEET BIXIN. 
 
 burg, and Dauphiny ; in Scotland, on the borders of Loch Lomond, in chlorite slate, 
 and near Newton Stewart in Galloway, also in the Isle of Man. It bears the same 
 relation to dolomite, or massive magnesiau limestone, that calcspar bears to common 
 limestone. 
 
 BITTERSWEET. Stipites Dulcamara. The stems of Solatium Dulcamara (q.v.) 
 
 BITUMEN. This term includes a considerable number of inflammable mineral 
 substances, mainly consisting of hydrocarbons. They are of various consistence, from 
 thin fluid to solid, but the solid bitumens are for the most part liquefiable at a moderate 
 heat. The purest kind of fluid bitumen, called Naphtha, or Hock-oil, is a colourless 
 liquid of specific gravity 07 to 0*84, and with a bituminous odour. It often occurs in 
 nature combined with asphalt and other solid bitumens. Petroleum is a dark- coloured, 
 fluid variety containing much naphtha. Maltha or mineral tar is a more viscid 
 variety. The solid bitumens are Asphalt, already described (p. 425), Mineral tallow, 
 or Hatchctin, and Elastic bitumen, Mineral Caoutchouc or FJatcrite. (See the several 
 substances in alphabetical order. For the practical uses of bitumen, see lire's Diction- 
 ary of Arts, Manufactures and Mines, i. 308.) 
 
 BZ1TRET. C 2 H 5 N S 2 (dried at 100 C.); C 2 H 5 N 3 2 .H 2 (crystallised). A 
 product of the decomposition of urea and nitrate of xirea. It is isomeric with 
 acid cyanate of ammonium, 2CHNO.NIP, and may be regarded as a secondary 
 
 amide, N ] ^ TT , whereas urea is a primary amide containing the same radicle, 
 
 ( PTT 2 NO 
 
 N j jp ' and isomeric with neutral cyanate of ammonium, CHNO.NH 3 . 
 
 The formation of biuret from urea is represented by the equation 
 2CH 4 N 2 = C 2 H 5 N 3 2 + NH 3 . 
 Urea. Biuret. 
 
 To prepare it, urea is melted in an oil-bath for some time at 150 to 170 C. ; and as 
 soon as the evolution of ammonia ceases and the residue becomes pasty, this residue 
 is treated with a very small quantity of boiling water; the liquid, after filtration, 
 is precipitated by a solution of subacetate of lead ; the precipitate, consisting of cyanu- 
 rate and ammelidate of lead, is separated by filtration ; and the liquid, after being 
 treated with sulphuretted hydrogen to remove the excess of lead, and again filtered, is 
 evaporated till it crystallises. Biuret is then deposited in small granular crystals, 
 which may be purified by recrystallisation from water. It is also obtained, though 
 in small quantity, by the action of heat upon nitrate of urea. 
 
 Biuret dissolves very easily in water and in alcohol, and crystallises from the latter 
 liquid in long anhydrous leafy crystals, and from water in hydrated crystals, which 
 give off their water of crystallisation when exposed to dry air or dried at 100 C. It 
 dissolves without decomposition in cold strong sulphuric acid, and is not altered by 
 boiling with nitric acid, unless the acid is very strong. Its solution is not precipitated 
 by lead or silver salts, by gallic acid, or by tannin. On adding a few drops of a solu- 
 tion of copper salt to a solution of biuret, and then a slight excess of potash, a deep 
 red colour is produced. This reaction takes place also with solutions of biuret in acids 
 or in ammonia, and affords a very delicate test of its presence. Biuret when heated, 
 melts, gives off vapours of ammonia, and ultimately leaves pure cyanuric acid : 
 
 3C 2 H 5 N 3 2 = 2C 3 H 3 N 3 3 + 3NH 3 . 
 ("Wiedemann, Pogg. Ann. Ixxiv. 67.) 
 
 BIXIXST. A colouring matter contained in annotto (the red paste obtained by 
 crushing the seeds of the Bixa orellana}. According to Chevreul, annotto contains 
 two colouring matters, viz. orellin, a yellow dye, soluble in water and alcohol, but spar- 
 ingly in ether, and bixin, an orange-coloured dye, sparingly soluble in water, easily in 
 alcohol and ether. According to Kerndt, bixin is C 16 H 26 2 , and when exposed to the 
 air, and in the moist state, is partly converted into orellin. According to Preisser, 
 Ann. Ch. Pharm. lii. 382), bixin is obtained in small slightly yellowish crystals, by 
 treating lumps of pure annotto with carbonate of sodium, precipitating with basic 
 nitrate of lead, decomposing the precipitate with sulphuretted hydrogen, and evaporat- 
 ing the colourless filtrate. It is bitter, soluble in water, alcohol, and ether, volatile 
 when heated, turned yellow by sulphuric and nitric acids, orange-yellow by chromic 
 acid. Treated with ammonia in contact with the air, it is converted into & dark red- 
 brown substance, bixc'in, which is the red-colouring matter of annotto. It combines 
 with lead-oxide and alkalis, and is turned blue by sulphuric acid. (Preisser.) 
 
 According to Grirardin (J. Pharm. [3] xxi. 174), the name of bixin is applied 
 commercially to a variety of annotto, having si* to tuu times the colouring power of 
 
BLACK BAND BLEACHING. 601 
 
 common annotto, a superiority which it appears to owe to a qxiicker process of 
 extraction. 
 
 BXiACIL BAND. A variety of carbonate of iron. See IRON and CARBONATES. 
 
 BXiACZ CHAXiK. This mineral has a bluish-black colour, a slaty texture, soils 
 the fingers, and is meagre to the touch. It contains about 64 silica, 11 alumina, 11 
 carbon, with a little iron and water. It is found in primitive mountains, and also some- 
 times near coal formations. It occurs in Caernarvonshire and in the island of Isla. 
 
 BZiACl TACK. The miners distinguish blende, or mock lead, by this name. 
 It is an ore of zinc. 
 
 BXiACB. ZiEAD. See GRAPHITE and PLUMBAGO. 
 
 BZiACXL WA3>D. One of the ores of manganese. 
 
 The name of an alkaloid said to exist in China blanca. 
 A kind of crude soda, less powerful than barilla, obtained at 
 Aigucs-Mortes, by the incineration of Salsola Tragus and 8. Kali. 
 
 BXiAPS OBTUSA. This insect contains, according to Hornung and Bley (J. 
 pr. Chem. vi. 237), a red colouring matter, fatty and volatile oil, resin, formic acid, 
 uric acid, chitin, wax, and other constituents. 
 
 BXiEACHXNG. The chemical art by which the various articles used for clothing 
 are deprived of their natural dark colour and rendered white. 
 
 The oldest method of bleaching, which is still practised in some localities, and for 
 particular kinds of goods, especially for hempen and flaxen goods, consists in extending 
 the tissues on the grass of a meadow, so as to expose them for some days to the 
 united action of light, air, and water, then washing them in alkaline ley, and repeating 
 this series of operations a considerable number of times. 
 
 This mode of bleaching is effective, but slow, and involves a great amount of 
 labour. About 1785, Berthollet proposed the use of chlorine for bleaching vegetable 
 tissues ; but its introduction met with considerable opposition from manufacturers, 
 because the mode of applying it being but imperfectly understood, its action was un- 
 certain, and moreover it was found to injure the tissues ; gradually, however, these 
 difficulties have been overcome, and the use of chlorine for bleaching cotton goods has 
 entirely superseded the old method. Chlorine was first used in ^the form of aqueous 
 solution; afterwards solutions of chlorine in caustic alkalis, that is to say, solutions of 
 hypochlorite of potassium or sodium, the so-called chlorides of potash and soda, were 
 used ; but these compounds are now almost entirely superseded by the hypochlorite of 
 calcium, the so-called chloride of lime or bleaching powder. This substance is prepared 
 on a large scale by exposing slaked lime to the action of chlorine gas, whereby a solid 
 mixture of hypochlorite and chloride of calcium is produced. It is soluble in water, 
 and the solution is used for steeping the goods to be bleached. By itself it exerts no 
 bleaching action whatever ; but by exposing the fabrics wetted with it to the action of 
 the carbonic acid in the air, or more quickly by steeping them in a bath of dilute sul- 
 phuric or hydrochloric acid, the salt is decomposed, and the liberated hypochlorous 
 acid exerts its bleaching action on the tissues. 
 
 The strength of the chlorine-liquor is a matter of great importance. The stronger 
 the liquor, the more rapid will be its action ; but on the other hand, the greater will be 
 the chance of injury to the goods. In practice it is not found safe to use a solution 
 marking more than 2 or 3 of Baum^'s hydrometer, or 0-5 of Twaddell's, equivalent 
 to specific gravity 1002-5 ; and even this must be carefully removed by subsequent 
 washing, and in some cases by the use of hyposulphite of sodium or other antichlors. 
 (See ANTICHLOR.) 
 
 Wool and silk are for the most part bleached with sulphurous acid, chlorine and 
 the hypochlorites being found to exert an injurious action upon them. 
 
 The rationale of bleaching is not thoroughly understood, but the most probable expla- 
 nation of the action is, that it is due in all cases to oxygen in the peculiar active form 
 called ozone. That active oxygen does possess this bleaching power is well-known : 
 witness the action of peroxide of hydrogen on vegetable colours. Now in the old 
 method of bleaching by exposure, light is an essential element of the action, the 
 bleaching taking place much more quickly in sunshine than under a clouded sky. But 
 Schonbein's investigations have also shown that ordinary atmospheric oxygen passes 
 into the active state under the influence of light and moisture. Chlorine abstracts 
 hydrogen from the colouring matter, and the oxygen thus set free produces the bleach- 
 ing action. The action of sulphurous acid appears at first sight to be apposite to 
 this, viz. deoxidising ; but it is known from Schonbein's investigations, that an aqueous 
 solution of sulphurous acid or an alkaline sulphite exposed to air and light quickly 
 brings a portion of the oxygen in contact with it into the active state ; hence also the 
 bleaching action may in this case be due to oxidation. Sometimes, however, the 
 
602 BLEACHING. 
 
 sulphurous acid appears to unite directly with the colouring matter of the tissue to 
 form a colourless compound. 
 
 The actual process of bleaching by means of chlorine or sulphurous acid is always 
 preceded or accompanied by certain cleansing operations, consisting in washing with 
 water, and boiling with alkaline leys or soap, the object of which is to remove re- 
 sinous, fatty, and other impurities, either natural to the fibre or introduced accident- 
 ally or intentionally in the course of manufacture. All these substances impair the 
 whiteness of the fabric, and often interfere greatly with the processes of dyeing and 
 printing. Indeed, their removal by the means above mentioned, constitutes a very 
 important part of the bleaching process, a large portion of the colouring matter being 
 got rid of at the same time, so that the chlorine or sulphurous acid serves to give only 
 the last finish. Cotton and linen goods are cleansed by washing with water and 
 boiling with alkaline leys : formerly potash and soda were used for the purpose, but 
 they are now nearly superseded by lime, at least for the first cleansing, as this sub- 
 stance, besides being much cheaper than the alkalis, is less likely to injure the fabric. 
 Silk and wool are cleansed by scouring or boiling with water and soap, as they cannot 
 bear the action of pure alkaline solutions. 
 
 Bleaching of Cotton. The series of operations in the bleaching of cotton, may be 
 thus generally described : 
 
 1. Boiling, or as it is technically called bucking or bowking, with milk of lime (lib. 
 of lime to 14 Ibs. of cloth, and about as much water as will cover the cloth). This 
 operation converts the resinous and fatty matters into lime-soaps, 
 
 2. Washing with water, in the dash-wheel, or other suitable machine, to remove 
 the excess of lime and various soluble and mechanical impurities introduced in the 
 process of manufacture. 
 
 3. Souring in hydrochloric acid of specific gravity I'OIO or 2 Twaddle, to decom- 
 pose the lime-soaps and remove the lime. Dilute sulphuric acid is sometimes used, 
 but hydrochloric acid is preferable, as chloride of calcium is much more soluble than 
 the sulphate. 
 
 4. Washing again to remove excess of acid. 
 
 5. Bowking with a solution of soda-ash and resin (170 Ibs. soda-ash, and 30 Ibs. 
 resin, to 3500 Ibs. of cloth, and about the same quantity of water as in the lime- 
 process). An imperfect soap is thus produced, which removes the rest of the fatty- 
 matter and dirt. 
 
 6. Washing, and then immersing the cloth in the chlorine-bath ; this is called chlor- 
 inating or chemicking. The solution, which should be quite clear, has a specific 
 gravity of 1002*5 or i Twaddle. 
 
 7. Souring in hydrochloric or sulphuric acid of 2 Twaddle, to set free the hypo- 
 chlorous acid ; then washing and drying. 
 
 The strength of the various liquors must be regulated according to the quality of 
 the goods to be bleached, and the manner in which the operations are conducted : 
 the preceding proportions of lime, soda, resin, &c. are given merely as examples. Some- 
 times carbonate of soda is used in the cleansing operations, sometimes a mixture of 
 soda-ash and quick lime, which of course produces caustic soda. It is often found 
 advantageous to perform the souring and chlorinating in two successive operations, the 
 goods being washed between the two. This treatment is found to be less likely to 
 injure the fibre than long-continued exposure to the action of the liquid in one opera- 
 tion. In all the operations, it is important to keep the cloth completely immersed in 
 the liquid, and never to leave it exposed to the air before washing ; because the acid 
 or alkaline liquids, if allowed to become concentrated on it by drying, are sure to 
 destroy the fibre. 
 
 Bleaching of Linen. Linen contains a much larger quantity of colouring matter 
 than cotton, and in bleaching loses nearly a third of its weight, whereas cotton loses 
 only one-twentieth. This large amount of colouring matter is not natural to the flax, 
 but is chiefly produced in the operation of steeping or water-retting, by which the 
 textile fibres surrounding the stem of the plant are separated from the woody 
 portion. 
 
 The colouring matter of steeped flax is insoluble in water, acids, and alkalis, but 
 becomes soluble in alkalis after exposure to light or to the action of chlorine. Gene- 
 rally speaking, it is not found advantageous to rely on the action of chlorine alone for the 
 bleaching of linen ; the old method of exposure on the grass, crofting, as it is called, 
 being almost always resorted to in addition. Moreover, it is not found possible to get 
 rid of the colour entirely in one series of operations, several alternate exposures to 
 oxygen or chlo ine and to alkali being required to render the material perfectly 
 white. 
 
 The following is an outline of the Irish method, as practised in the neighbourhood 
 of Belfast : 
 
BLEACHING. 603 
 
 1. Steeping. After the linen has been scoured in the fulling-mill, warm water is 
 poured upon it, and it is left immersed for two or three days, till acid fermentation 
 sets in. 2. Boiling with potash-ley, soda-ley, or lime-water. 3. Washing. 4. Croft- 
 ing or exposure on the grass for two or three days. 2', 3', 4'. The bowking, washing 
 and crofting are repeated several times, six repetitions sufficing for the finer linens, 
 and as many as twelve being sometimes required for the coarser. 5. Souring with 
 hydrochloric- or sulphuric-acid of 2 Twaddle. 6. Washing, as in 3. 7. Soaping, that 
 is, rubbing with solid soap or with very strong soap-suds. 8. Boiling in alkaline-ley of 
 about | per cent. 9. Washing, as in 3 and 6. 10. Crofting for two days. 11. Chlo- 
 rinating with a solution of hypochlorite of potassium, prepared by treating common 
 bleaching powder with carbonate of potash. The liquor used is very weak. 
 12. Washing, as in 3 and 6. 13. Souring, as in 5, but with somewhat weaker acid. 
 14. Washing. 15. Soaping, as in 7. 16. Scalding, by immersing the cloth in soap- 
 suds mixed with a little potash-ley of | B., and heating the liquid to boiling. 
 17. Washing. 18. Crofting. 19. Washing and drying. 
 
 Bleaching of Silk. Eaw silk contains, besides the true fibre, about 40 per cent, of 
 foreign matter, viz. albumin, gelatinous substances, wax, fat, resin, and colouring 
 matter. These substances are removed by boiling the silk in a strong solution of 
 soap, then washing and rinsing. The silk after this treatment, is nearly white, but 
 to render it quite white, it is sulphured, that is to say, suspended in the moist 
 state in a large box in which sulphur is burned. About 1 Ib. of sulphur is required 
 for 20 Ibs. of silk, and to obtain perfect whiteness, about four sulphurings, of twelve 
 to sixteen hours each, are required. 
 
 As the silk loses considerably in weight, when cleansed in the manner above de- 
 scribed, it is sometimes thought better to subject raw silk to the bleaching process 
 without previous cleansing. For this purpose, a bath is used composed of 7 pts. hydro- 
 chloric acid and 3 pts. nitric acid, sometimes with addition of sulphuric acid, the 
 liquid being diluted with water to 3 Bm. In this mixture, the skeins of silk are 
 suspended, and repeatedly moved about for two or three hours, then wrung, twice 
 washed, and afterwards sulphured. Sometimes the bleaching in the acid mixture is 
 preceded by softening in a soap-bath ; sometimes this softening process is made to 
 intervene between the acid bath and the sulphuring. 
 
 Bleaching of Wool. Wool is never bleached in the fleece, because its whiteness 
 would be destroyed in the subsequent operations of spinning and weaving ; the bleach- 
 ing is, therefore, always performed on the yarn or on the woven fabric. A consider- 
 able portion of the dirt which adheres to the wool while on the animal, is removed 
 by the washing which precedes shearing ; this washing also removes the sweat, which 
 is a kind of soap, chiefly composed of fatty matter and potash. But there still remains 
 a quantity of free fat, which is generally removed by steeping and agitating it for ten 
 or fifteen minutes in soap and water, or soda-ley, sometimes in putrid urine diluted 
 with two or three measures of water, sometimes even in pure water. To prepare the 
 wool for spinning, it is then greased with oil, as, without this preparation, it woiild be 
 too harsh and very liable to tear. The grease thus added must of course be removed 
 in the subsequent bleaching process. The treatment consists in passing the wool 
 through a soda-bath, then through a soap-bath, washing in lukewarm water, and 
 suspension in the sulphur chamber, this series of operations being repeated several 
 times, and finally passing the bleached wool through a blue-bath, which is a very weak 
 solution of soap containing hydrate of alumina and indigo. The sulphuring is some- 
 times omitted, and the cleansing is effected entirely by ammonia. 
 
 Bleaching of materials for Paper. The rags used for making paper are bleached in 
 the same manner as cotton goods. After being properly sorted and chopped or torn 
 in pieces, they are bowked with lime-water, soured, washed in the rag-engine, which 
 is a combined washing machine and filter, then chlorinated, soured, and washed 
 again, and finally treated with a solution of hyposulphite of sodium to remoA T e the last 
 traces of chlorine. (See ANTICHI.OK.) 
 
 "For bleaching old paper: Boil the printed paper for an instant in a solution of 
 caustic soda. Steep it in soap-suds, and then wash it ; after which it may be reduced to 
 pulp. The soap may be omitted without much inconvenience. For old written paper 
 to be worked up again : Steep it in water acidulated with sulphuric acid, and then 
 wash it well before it is taken to the mill. If the water be heated, it will be more 
 effectual. To bleach printed paper without destroying its texture: Steep the leaves 
 in a caustic solution of soda, either hot or cold, and then in a solution of soap. 
 Arrange them alternately between cloths, as paper-makers do thin sheets of paper 
 when delivered from the form, and subject them to the press. If one operation do not 
 render them sufficiently white, it may be repeated as often as necessary. To bleach 
 old written paper without destroying its texture : Steep the paper in water acidulated 
 \\ith sulphuric acid, cither hot or cold, and then in a solution of oxygenated muriatic 
 
604 BLOOD. 
 
 acid ; after which immerse it in water, so that some of the acid may remain behind. 
 The paper, when pressed and dried, is fit for use." Ure. 
 
 The bleaching of straw is effected by steeping it in hot water, heating it repeatedly 
 during several days, and immersing it in weak solution of chloride of lime or of soda, 
 alternately witli weak alkaline leys. 
 
 Bleaching of Horse-hair. White horse-hair requires further bleaching to adapt it to 
 many purposes. The process consists in washing it in soda-solutions, not too strong, 
 and at the heat of the hand, then hanging it up in the sulphur-chamber, and repeating 
 these processes several times. 
 
 [For further details, see Ure' 's Dictionary of Arts, Manufactures, and Mines, i. 318, 
 also Muspratfs Chemistry, i. 299.] 
 
 BXiE ACHING- POWDER. Chloride of Lime, Oxymuriate of Lime. See HYPO- 
 CHLORITES, under CHLORINE. 
 
 BLEITJIERITE. Basic Antimonate of Lead (p. 326). 
 
 BZiEXIDE. Native SULPHIDE OF ZINC. (See ZINC.) 
 
 BXiODITE. Probably the same as ASTBACANITE (i. 429). 
 
 BIiOOD. The blood of the higher animals forms a rather viscous opaque liquid, 
 heavier than water, and of more or less intense red colour, arterial blood being always 
 lighter than venous. It is transparent in very thin strata. The specific gravity of 
 normal human blood averages about 1*055, but under certain circumstances varies 
 between 1*045 and 1*075; it is slightly less in women than in men, and still less in 
 children. The specific gravity of arterial blood is rather less than that of venous. 
 The blood of most domestic animals differs but little in specific gravity from that of 
 man (specific gravity of bullock's blood = 1*060 ; of sheep's = between 1*050 and 
 1*058). The blood has always an alkaline reaction. When warm it has a peculiar 
 odour, generally more powerful in the male than in the female. 
 
 From two to five minutes after the blood has left the circulation, it begins to coagu- 
 late, a film gradually extending from the surface and circumference, so that the whole 
 becomes gelatinous in the course of from seven to fourteen minutes. The coagulum 
 (fibrin and blood-corpuscules') then gradually contracts and separates from the watery 
 portion of the blood (serum) ; and in from twelve to forty hours, the blood is completely 
 resolved into serum and thick red clots, which swim beneath it. The blood of men 
 coagulates more slowly, but yields a denser coagulum than that of women ; in the 
 embryo it coagulates imperfectly. Arterial blood coagulates more rapidly than 
 venous. The presence of air and a rise of temperature promote coagulation ; cold 
 retards it. 
 
 The constituents of blood are partly in solution and partly suspended (blood-cor- 
 puscules). Swammerdam, in 1664, first observed corpuscules in the blood of the frog ; 
 he described them as oval. Leeuwenhoek (Phil. Trans. 1664, p. 23) found that human 
 blood consisted of round bodies swimming in an opaline liquid, and that the colouring 
 matter of the blood of mammalia, fish, and frogs was contained in these corpuscules, 
 which were round in men, oxen, sheep, and rabbits, but oval in birds, frogs and fish. 
 Later observers discovered that all blood-corpuscules are flattened. The coloured 
 corpuscules consist of a colourless enevelope, the contents of which are red, or by trans- 
 mitted light yellow, and each is slightly depressed and concave in the centre. In 
 general they do not possess any nucleus, and only a few of them exhibit something 
 approaching to one. The size of the red corpuscules varies considerably in different 
 animals, the smallest being found in the blood of the Moschusjavanicus, and having a 
 diameter of 0*00208 mm. (Gulliver), and the largest in that of the Cryptobronchus 
 japonicus (0*05623 mm. broad, and 0*0333 mm. long, V. d. Hoeven). The human 
 corpuscules have a diameter of 0*00752 mm., those of the carnivora between --^ 
 and ~ mm. and their thickness is generally \ or i of their diameter. The blood- 
 corpuscules of embryos are larger than those of the grown up animals of the same 
 species. Milne-Edwards asserts that the size of the corpuscules is closely connected 
 with the size of the organs of respiration. To prevent their shrinking up during 
 measurement, C. Schmidt moistens a glass plate with an exceedingly thin layer of the 
 blood to be examined, so that it dries up immediately. The corpuscules thus adhere 
 by their flat sides to the glass, and remain of this same size when the serum has dried 
 up. The blood of different animals may frequently be distinguished under the micro- 
 scope by the size of the corpuscules. 
 
 According to Schmidt, the specific gravity of the blood-corpuscules of a healthy man 
 varies between 1*0885 and 1*0889; in cholera it sometimes increases to 1*1025 or 
 1*1027. The red corpuscules sink in the serum ; they are generally equally coloured ; 
 a few, however, are sometimes darker, sometimes lighter than normal corpuscules. The 
 difference in colour is dependent upon the absolute amount of hsematin in the cor- 
 
BLOOD. 605 
 
 puscules, the proportion of which relative to the serum influences the general colour of 
 the blood. The form of the corpuscules also affects the colour of the blood, for if these 
 be swollen by addition of water, they become more spherical, and the blood appears of 
 a darker colour. Mulder supposes that the bright colour of arterial blood is due to the 
 greater thickness of the enveloping membrane of the corpuscules. Nasse states that 
 by the action of carbonic acid gas, the cells become darker in colour and turbid in the 
 centre. All substances such as caustic alkalis, and several organic acids, which burst 
 the corpuscules, or otherwise liberate their contents, turn the blood dark brownish-red, 
 while those, such as nitrate and iodide of potassium, phosphate and carbonate of 
 sodium, &c. which contract and so thicken the external membrane, render the blood 
 of a lighter colour. 
 
 The average proportion by weight of moist blood corpuscules in a healthy man = 
 51'2 % (47*2 54-2 %). According to Vierordt, 1 cubic millimetre of blood contains 
 5,055,000 corpuscules. The amount of dry corpuscules in the blood of man is variously 
 given = 12-9% (Prevost and Dumas), 14-1 (13-1 15-2 %) (Becquerel and 
 Kodier), 11*65 (Nasse). The blood of women contains fewer corpuscules than that 
 of men, amounting to 36-924 % moist corpuscules (C. Schmidt), and 1272 dry (11-3 
 1375 %) (Becquerel and Kodier). The blood of middle-aged men and animals con- 
 tains more corpuscules than that of older or younger individuals of the same species. 
 The amount of corpuscules also varies in the blood of different animals, that of birds 
 containing most, that of the carnivorous and herbivorous mammalia less, and that of 
 cold-blooded animals by far the least, as will be seen from the following table, in which 
 the percentages of dry corpuscules are given : 
 
 Chicken. Pigeon. Ox. Sheep. 
 
 15-71 (Pr. and Du.) 15-57 (Pr. and Du.) 970 (Andral.) 9-35 (Pr. and Du.) 
 
 14-46 (Nasse.) 12-18 (Nasse.) 9-80 (Andral.) 
 
 15-00 (Poggiale.) 14-30 (Poggiale.) 12-30 (Poggiale.) 9-24 (Nasse.) 
 
 10-20 (Poggiale.) 
 
 Dog. Frog. Eel. Carp. 
 
 12-38 (Pr. and Du.) 6*90 (Pr. and Du.) 6-00 (Pr. and Du.) 8-23 (Berthold.) 
 12-38 (Nasse.) 4'58 (Berthold.) 
 
 12-60 (Poggiale.) 
 
 The proportion of corpuscules in the blood of different vessels also varies. In general, 
 arterial blood contains fewer corpuscules than venous, the blood of the portal vein 
 fewer than that of the jugular vein, while that of the hepatic vein contains far more 
 than that of the portal vein, jugular veins, vena cava or splenic vein (Lehman n). 
 Lehmann found 55-652 % moist corpuscules in the arterial blood of a horse, 48*996 in 
 jugular blood, 5 5 -6 8 8 in that of the vena cava. 
 
 Insufficient nourishment and long abstinence, as well as repeated blood-letting, 
 diminish the quantity of blood-corpuscules ; the amount increases if large quantities 
 of fat are taken in the food. It is also influenced by disease, a constant increase being 
 observed in plethora, in the earlier stages of heart-disease, in spinal irritation, and 
 in cholera. Decrease occurs in all cases where the consumption of blood is greater than 
 the supply, e. g. diarrhoea, intermittent fever, affections of the brain, and chlorosis 
 (8-6 13% Becquerel and Eodier). The percentage of water in the corpuscules bears 
 a pretty constant relation to that of the serum, so that when the amount of water 
 decreases in the serum, it also decreases in the corpuscules. 
 
 Colourless blood-corpusculcs are always present in blood, but at least in the case of the 
 warm-blooded animals, in much smaller quantity than the coloured corpuscules. They 
 are generally almost spherical, but sometimes lenticular ; they have a granulated enve- 
 lope, and generally a round nucleus, which is more rarely oval or kidney-shaped, and 
 strongly refracts light : sometimes it is formed of several small nuclei grouped together. 
 They are identical with the lymph- and chyle-corpuscules, and do not differ much 
 from the pus- and mucus-corpuscules. They are unelastic, and their envelope is so 
 viscous that the corpuscules readily adhere to one another. They circulate less rapidly 
 in the blood than the coloured corpuscules, and contain an albuminous liquid holding 
 very minute granules in suspension. Dilute acetic acid gradually dissolves the ex- 
 ternal membrane. In human blood they measure 0-01128 mm. in diameter. They 
 are specifically lighter than the red corpuscules, since they contain more fat and no 
 hsematin. In healthy blood they bear to the red corpuscules the ratio of 1 : 1-373 
 (Donders and Moleschott); the number increases during digestion and diminishes 
 by fasting, the increase commencing thirty minutes after partaking of food, and lasting 
 two hours. They increase in certain diseases, frequently in pneumonia and tuber- 
 culosis. In leuchsemia this increase often amounts to one-fourth of the blood-corpus- 
 cules. The splenic blood contains large quantities of colourless corpuscles, about one- 
 fourth or one-third of the total amount of corpuscules. 
 
606 BLOOD. 
 
 Gases. As early as 1674, free gases were supposed to be dissolved in blood, and 
 the question was finally set at rest by the experiments of Magnus. The objection 
 raised by Lagrange to Lavoisier's theory, that if combustion took place only in the 
 lungs, the other parts of the body would have a lower temperature, led him to suppose 
 that the blood merely dissolved the inhaled oxygen, and afterwards distributed it 
 throughout the system. Fourcroy was, however, of opinion that combustion took 
 place principally in the lungs, and that only a part of the oxygen was dissolved by 
 the blood. H. Davy remarked that blood in contact with oxygen absorbs a certain 
 quantity of the gas, giving off carbonic acid in exchange, and Nasse observed that 
 blood in an atmosphere of hydrogen evolved carbonic acid. It has also been remarked 
 that in an atmosphere of nitrogen, arterial blood evolves oxygen, but not venous 
 blood. Mayow, Vogel, and others, obtained carbonic acid from the blood by means 
 of the air-pump. Magnus also used the air-pump in his experiments, but collected 
 the gas under mercury, and found the gases in arterial blood to consist of 14-5% 1ST, 
 62-3% CO 2 , and 23-2% 0, in venous, 13'1% N, 71-6% CO 2 , and 15-3% 0. L. Meyer 
 undertook a series of experiments on the gases of blood, under the guidance of Bunsen. 
 The blood was diluted with ten times its bulk of water, and the gases were collected by 
 boiling the liquid in vacuo at a very gentle heat : the free gases were thus obtained. 
 A few crystals of tartaric acid were then added, and the blood again boiled, whereby 
 the combined gas was liberated. The following table contains the quantities of gases 
 (at and 0760m.) in 100 vols. of blood. 
 
 Free Gas. O. N. Free CO*. Co $? ed Total. Total 
 
 Art. Carol. (Dog) (1) 20-88 12-43 2'83 5-62 28-61 34-23 49-49 
 (2) 25-50 14-29 5-04 6-17 28-58 3475 54-08 
 
 Blood at and 1 met. absorbs 1-151 vol. carbonic acid, besides 0-481, independently 
 of the pressure (combined CO 2 ). Defibrinated calf s blood, free from air, absorbs 
 under different pressures the same amount of oxygen (9'3% vol. at and 0760 m.) 
 Serum absorbs a much smaller proportion of gases than defibrinated blood. The red 
 colouring matter absorbs a considerable quantity of oxygen, and evolves a little car- 
 bonic acid. Gr. Harley found that blood, or defibrinated blood, absorbed oxygen when 
 shaken up with air, and evolved carbonic acid, but in less quantity than corresponded 
 to the oxygen absorbed. 
 
 It is difficult to explain satisfactorily why blood should absorb so much more 
 carbonic acid than pure water at the same temperature ; it is perhaps partly owing to 
 the neutral alkaline carbonate in blood forming acid carbonate, but this does not account 
 for all the carbonic acid absorbed. Liebig has remarked that water containing 1 % 
 phosphate of sodium absorbs twice as much carbonic acid as pure water, while water 
 containing 15 % chloride of sodium only takes up half as much. It is also supposed 
 that oxygen, of which blood absorbs from 10 to 13 % of its vol., and water only 
 0*925 %, combines in a loose way with blood, like nitric oxide with ferrous sulphate, 
 since the vol. of gas absorbed does not increase proportionally with the pressure 
 (Liebig). It has also been shown that part of the oxygen thus taken up by blood 
 cannot again be separated. (See GASES, ABSORPTION OF.) 
 
 Constituents of the coloured blood-corpuscules. Berzeliushas shown that 
 the coloured corpuscules contain an albuminous substance (globulin) differing from 
 albumin. Schmidt separated the corpuscules by means of sulphate of sodium, and 
 found them to contain 87'59 globulin and 12-31 % hsematin. Mulder considers the 
 outer membrane of the corpuscules to be binoxide of protein, a hypothetical substance ; 
 others have taken it for fibrin. Its composition does not appear to be fixed, since the 
 membrane of different corpuscules is variously affected by the same reagents. 
 
 Blood-crystals ; H&matocrystallin. 0. Funke first completely investigated the na- 
 ture of the crystalline substance of the red corpuscles. Funke and Kunde obtain the 
 crystals by adding to a drop of blood, water, ether, alcohol, or chloroform, allowing 
 the mixture to dry slightly on a glass plate, and then covering the whole with a 
 glass cover. Lehmann passes a slow stream of oxygen or nitrous oxide for about 
 fifteen minutes into a mixture of blood and water, and afterwards carbonic acid, till 
 the liquid turns bright red and becomes turbid, whereupon it crystallises. "When a 
 considerable quantity of blood is to be operated upon, it is best to leave it to coagulate, 
 press the clot to remove the serum, cut it in pieces, and wash it on a linen filter with 
 water till the filtered liquid amounts to about 1^ times or twice the volume of the 
 water used. The liquid is then to be poured into a glass cylinder, oxygen gas passed 
 into it for about half an hour, and then carbonic acid for ten or fifteen minutes, after 
 which it ^is left at rest. If no crystals form after about two hours, the liquid must be 
 mixed with \ of its volume of alcohol (Lehmann.) Light promotes the crystallisation, 
 which is not caused by evaporation of water, since blood will crystallise as readily 
 
BLOOD. 607 
 
 with twice its volume of water as with only half that quantity. It cannot be doubted 
 that both oxygen and carbonic acid, by their chemical action on the contents of the 
 corpuscules, are instrumental in the formation of the crystals. The form of the 
 crystals varies in the blood of different animals; those obtained from the blood of 
 men, most mammalia, and fish, form prisms ; from the rat, mouse, and guinea-pig, 
 tetrahedrons ; from the squirrel, hexagonal tablets ; and from the German marmot, 
 rhombohedrons (of about 120), or very thin hexagonal plates.* The tetrahe- 
 dral crystals dissolve with peach-blossom-colour in 600 pts. of water, the pris- 
 matic with dark-red colour in S4 pts. water. Nitric acid turns the crystals almost 
 black, but dissolves them on warming, and acquires a yellow colour. Their solution 
 is decolorised by chlorine, which prcipitates white flakes ; it is turned dark brownish- 
 red by carbonic oxide, and rendered turbid and brownish-red by nitrogen. The 
 same sized crystals from the same blood often differ in intensity of colour and have 
 probably not always the same composition. They seem to be an albuminous substance. 
 The solution of the tetrahedral crystals coagulates at about 63 C., that of the pris- 
 matic crystals between 64 and 65. The crystals exhibit, according to Lehmann' s 
 analysis, the percentage composition of the albuminoids : 
 
 Carbon 55-41 55'24 55'18 
 
 Hydrogen .... 7'08 7'12 7'14 
 
 Nitrogen .... 17'27 17'31 16-40 
 
 Sulphur .... 0-25 0-21 0-25 
 
 Oxygen .... 19-99 25-12 2Q-Q3 
 
 100-00 IOC -00 100-00 
 
 Hcematin is peculiar to the blood-corpuscules of vertebrate animals, and in some way 
 combined with the remaining albuminous contents of the corpuscules. It is obtained 
 as an amorphous blackish-brown substance, by treating the corpuscules with sulphate 
 of sodium, extracting the residue with alcohol containing sulphuric acid, and treating 
 with ammonia, water, alcohol, and ether. It is insoluble in water, alcohol, ether, 
 acetic ether, and oils, both fat and volatile, but readily soluble in alcohol containing 
 sulphuric or hydrochloric acid. It is not dissolved by concentrated mineral acids. 
 Aqueous or alcoholic solutions of alkalis or their carbonates dissolve hsematin in all 
 proportions. A sulphuric acid solution of hsematin which has been turned red by 
 addition of alkali, exhibits dichroi'sm, appearing green by transmitted and red by 
 reflected light. If hsematin be allowed to stand in contact with pure concentrated sul- 
 phuric acid, it may be obtained perfectly free from iron, without suffering any perceptible 
 change in its properties. Berzelius found in the dry blood corpuscules of men and 
 oxen 0-38 % metallic iron, and since Mulder has found 6'64 % iron in hsematin, the 
 corpuscules would contain 572 % hsematin, and the blood 0'732 %. Becquerel and 
 Roclier found in blood, 0*0565 % iron, and 14'11 % corpuscules, which would give 
 6'02 pts. hsematin to every 100 pts. corpuscules. In disease, the proportion of hsematin 
 to the whole blood probably varies with the corpuscules. It is not known whether 
 there is a fixed relation between hsematin and the albuminoid of the corpuscules. 
 Mulder assigns to it the formula C^H^XPO*. The arterial blood of the horse contains 
 rather less haematin than that of the outer jugular vein ; the corpuscules of the liver- 
 blood contain far less than those of the vena porta. The proportion of iron to dry 
 corpuscules in arterial blood = 1 : 394 ; in that of the jugular vein 1 : 390 ; of the 
 vena porta 1 : 312 ; of the liver 1 : 500 (Lehmann.) Poggiale found 0-126 % ferric 
 oxide in human blood, in that of the ox 0-125, calf 0-111, dog 0*145, sheep 0*106, chicken 
 0-075. 
 
 A substance called hcemato'idin has been observed in blood extra vasated in the tissues 
 of living animals. It is sometimes amorphous, in grains and little globules ; some- 
 times in crystals belonging to the monoclinic system. It is transparent, strongly 
 refracting, yellowish-red or ruby-red, insoluble in water, alcohol, ether, acetic acid, 
 and dilute mineral acids. It generally turns ardent red on addition of potash, 
 gradually disintegrates, and splits up into red granules, which gradually dissolve. 
 The hsematoi'din is not reprecipitated by neutralising the alkali. By the action of con- 
 centrated sulphuric acid, the sharp contour of the crystals vanishes, and the colour of 
 the round concretions first turns brownish-red, then green, blue, and rose, and finally 
 dirty yellow. In the liquid, iron may sometimes be detected, but not always. Ac- 
 cording to Kobin, its formula is C 14 H 18 N 2 3 . 
 
 The nature of the nuclei which sometimes occur in the corpuscules is unknown. 
 
 A considerable quantity of the fat of blood occurs in the corpuscules, nearly the 
 whole of the so-called phosphorised fats being contained therein. Lehmann found 
 2-214 and 2*284% fat in the. dry corpuscules from bullock's blood. The ethereal 
 
 * Figures of these crystals are given in Funke's Atlas of Physiological Chemistry (Leipzig 1853 also 
 published by the Cavendish Society) ; and in the Handworterbuch der Chemie, 2te Aufl. ii. [2] 136. 
 
608 BLOOD. 
 
 extract of these corpuscules yielded 22 % acid ash, consisting of acid phosphate of 
 sodium, from which it is probable that phosphogly eerie acid is contained in the cor- 
 puscules. The corpuscules in the blood of different vessels do not contain the same 
 amount of fat. In the moist corpuscules of the carotid artery of the horse, were found 
 0-608 % fat ; in the externaljugular vein 0-652 % ; in the vena porta 0752 ; in liver- 
 blood 0-684. Dry corpuscules separated from arterial blood by sulphate of sodium con- 
 tained 1-842 % fat ; from venous blood 3*595 %. 
 
 The solid constituents of the corpuscules contain rather less than 6% extractive 
 matter, the nature of which is unknown. They also contain a free or loosely com- 
 bined nitrogenised organic acid. 
 
 Moist corpuscules contain on the average 68-8 % water (Lehmann). Taking into 
 account the amount of serum enclosed in the coagulum, the corpuscules contain a much 
 smaller proportion of soluble salts than the serum. It will be seen from the analyses by 
 Schmidt (p. 611), which are the most trustworthy, that the corpuscules contain prin- 
 cipally phosphates and potassium salts, and, in smaller quantity, chlorine, sulphuric 
 acid, soda, and earths, while the serum contains proportionally less chloride of potassium 
 and phosphate of sodium, and more chloride of sodium, sulphuric acid and earths. In 
 man the moist corpuscules contain 07282 % salts. The blood of those animals which 
 contained most corpuscules also contains most alkaline phosphates (Nasse). The 
 corpuscules contain less earthy phosphates than the serum. Iron belongs almost 
 exclusively to the red corpuscules (hsematin). Clear serum contains no iron. (Nasse 
 and Schmidt). 
 
 Fibrin. As already stated, the spontaneous coagulation of the blood is caused 
 by the separation of the fibrin, which at the same time encloses all the corpuscules 
 and a portion of the serum. As soon as the blood has left the body, a film gathers 
 on the surface of the liquid, extending in the form of a star, from the sides of the 
 vessel towards the centre ; a clot, adhering to the sides of the vessel, then forms. 
 Often, within two minutes after the blood has been collected, it becomes viscid 
 and gelatinous, and after a time a few drops of liquid, gradually increasing in quantity, 
 separate from the jelly, till the coagulum swims in the serum. According to circum- 
 stances the coagulum is more or less contracted, consistent, viscous, and elastic. If 
 the coagulation be observed under the microscope, exceedingly fine straight threads 
 will be seen to shoot out from various points between the corpuscules, and, gradually 
 increasing in length, to cross one another, so that finally the whole forms a network 
 enclosing the corpuscules. If the amount of fibrin is small in comparison to the cor- 
 puscules, the coagulum is comparatively light ; denser, on the contrary, when the amount 
 of fibrin is large. A large quantity of water diminishes the consistence of the coagulum. 
 Various salts have the property of retarding or entirely preventing the coagulation of 
 blood. The alkalis and their carbonates and acetates have this effect, and rather 
 strong solutions of nitrate of potassium, nitrate of calcium, and chloride of am- 
 monium in a less degree. Most dilute acids also maintain the fluidity of blood, though 
 they render it rather more viscous. The venous blood of a healthy man contains 
 between 0-203 and 0-263% fibrin (Scherer), 0*220 (average, Becquerel and 
 Rodier), 0-250 % (Denis). Arterial blood contains more fibrin than venous. (See 
 FIBRIN.) 
 
 Constituents of the Serum. The average specific gravity of serum = 1-028; it is 
 less variable than the specific gravity of blood. The amount of water in the serum 
 varies between 88 and 95*6%, averaging 90*5 or 90'6% (Nasse). Women's blood 
 contains more water than that of men. According to C. Schmidt, the serum of man 
 contains 90-884 % water, and that of woman 91*715 ; and, according to Nasse, the 
 serum of pregnant women is more aqueous than of others. At an advanced age, the 
 amount of water increases considerably. The following table contains the percentages 
 of water in the serum of different animals : 
 
 Ox. Sheep. Dog. Chicken. 
 
 90-8 (Nasse.) 91*5 (Du, andPr.) 92-6 (Du. and Pr.) 92-5 (Du. and Pr.) 
 
 91-6 (Berthold.) 91'8 (Nasse.) 91-2 (Nasse.) 93-1 (Nasse.) 
 
 Pigeon. Frog. Eel. 
 
 94-5 (Du. and Pr.) 95'0 (Du. and Pr.) 90-0 (Du. and Pr.) 
 
 According to most observations, the serum of arterial blood contains more water than 
 that of venous blood. Simon found in the arterial blood of two horses, 2734% more 
 water than in the venous blood, and, according to Nasse, arterial blood contains 5'0% 
 more water than venous. As a general rule, the amounts of water in the serum and 
 of corpuscules in the blood are inversely proportional. An absolute diminution of 
 water has only been remarked in cholera. 
 
 Albumin is the most abundant of the constituents of the serum, amounting to be- 
 tween 6-3 and 7'1% of normal blood, and between 7'9 and 9'8 % of normal serum. 
 Neutral albuminate of sodium, which becomes turbid on addition of water, occurs not 
 
BLOOD. 609 
 
 only in morbid blood, but also in the blood of the spleen. The serum of the blood of 
 the vena porta gives less turbidity, and that of the liver-blood more, than of the 
 spleen. When the alkaline serum of liver-blood is neutralised with acetic acid, the 
 albumin does not coagulate on boiling till after several hours, while that of the vena 
 porta and other veins, as well as of the arteries, speedily coagulates on addition of 
 acetic acid and boiling. Hoppe is of opinion that the albumin in serum is not dis- 
 solved, but merely suspended in a state of fine division. According to Becquerel and 
 Rodier, normal man's blood contains 6*94: % (6'2 7'3 %) albumin, and that of women 
 7*05 (6'5 7'55) %. The blood of pregnant women was found to contain from the 2nd 
 to the 7th month, 7'0 6/8 % albumin, and in the last two months, 6-86-4 %. (J. 
 Regnault). Arterial blood contains less albumin than venous, and the amount in 
 liver-blood increases considerably during digestion ; it decreases in scurvy, puerperal 
 fever, and Bright' s disease, and increases in intermittent fever, cholera, &c. In typhus, 
 it amounted to 6-5 %, and in Bright's disease to only 4*93 %. 
 
 Fats. But few free fats are found in serum ; they occur chiefly saponified. Che- 
 vreul and Babington first discovered the presence of normal fats in blood. Oleic, mar- 
 garic, and stearic acids, both free and saponified, have been detected in the serum of 
 bullock's blood, and cholesterin is constantly present. Boudet describes, as a fat peculiar 
 to the serum, a substance extracted from its residue by hot alcohol (serolin), which 
 Gobley considers as a mixture of olein, margarin, cholesterin, and cerebrin. According 
 to Chevreul, phospholei'c acid (cerebrin) is contained in the fibrin and serum. Compared 
 with the corpuscules, that of the serum is more crystalline, less viscous, and colour- 
 less. Normal serum contains 0*2 % fat, and its solid residue 2'22% (Simon, Nasse, 
 Becquerel). The amount of fat in the blood is not increased by food rich in fat, nor 
 is it diminished by nourishment free from fat. During digestion, the amount of fat 
 in chyle and in the blood of the vena porta, has been found to increase considerably, so 
 as occasionally to render the serum turbid. According to Becquerel and Eodier, the 
 blood of women contains 0'57 p. m. fat and soaps, and that of men 0'69 p. m. Serum of 
 arterial blood contains less fat than that of venous, and the vena porta blood is richer 
 than the jugular. Becquerel and Rodier have found that, almost at the commencement 
 of every acute disease, the proportion of fat (especially cholesterin), in blood increases, as 
 well as in some chronic diseases, particularly in liver diseases, Bright's disease, tuber- 
 culosis, and cholera- 
 Little is known of the extractive matter of the serum ; it varies between 0'25 and 
 0'42 %. Lehmann found more in the arterial than in the venous matter of the horse. 
 Sugar (grape-sugar), is a normal constituent of blood. The blood of the vena porta 
 contains but traces, while that of the liver contains larger quantities. In normal 
 bullock's blood, it varies between 0-00069 and 0-00074 % (Lehman n). The blood 
 of a dog contained 0-0015, and of a cat 0'0021 %. In the blood of diabetic patients 
 Lehmann never detected more than 0-047 % sugar. The amount varies with the nature 
 of the food. Urea occurs in healthy blood to the amount of 0'0142 0'0177 %. It 
 has been detected by evaporating large quantities of serum and adding nitric or oxalic 
 acid to the residue. The quantity increases considerably in Bright's disease (1*5% 
 in serum, Bright and Babington), and in cholera (0'14 %). Uric acid has been 
 found in the blood of healthy as well as of diseased persons. G-arrod found between 
 0-0012 and 0-0055 in the serum in a case of Bright's disease. Creatine, crcatinine, hip- 
 puric acid, and hypoxanthine, have also been detected. According to Musing, alcohol 
 has been detected in the blood of men who had died from drinking brandy. Ma- 
 teucci states that goat's blood warmed with sulphuric acid evolves caproic acid. 
 Scherer has detected lactic acid in a case of puerperal fever. Fourcroy and Vauquelin 
 and others state that they have found bile-constituents in healthy blood ; they some- 
 times occur in morbid blood. Leuclne and tyrosine occur in small quantities in liver 
 and portal blood, in diseases of the liver. Little is known of the colouring matters 
 proper to the serum. An intense yellow coloration of the serum is often due either 
 to bile-pigment, which may be detected not only in icterus, but also in pneumonia. 
 Black, scarcely yellow, brown, or "red granules of pigment are said to have been de- 
 tected in the heart, large vessels, liver, and spleen, after intermittent fever. Blood con- 
 tains neutral carbonate of sodium (0-1628 % in bullock's blood, Lehmann), probably 
 as acid carbonate (Lehmann, Liebig). Meyer concludes from his experiments that 
 it is not present as acid carbonate. Blood seldom contains sulphates, and never more 
 than traces; it contains silicic rtt?'^(Millon), and according to Gr. Wilson, traces of 
 fluorine. Normal blood never contains ammonia, but that alkali is sometimes found in 
 disease (cholera, &c.) 
 
 Salts. The serum of man's blood contains 0-88 % (av.) salts, that of women 
 0-81 %. Lehmann gives the following composition of the ash according to the best 
 analyses : 61 -087 % chloride of sodium, 4-085 chloride of potassium, 28'880 carbonate 
 VOL. I. E R 
 
610 BLOOD. 
 
 of sodium, 3-195 phosphate of sodium (Na 2 HP0 4 ), 2784 sulphate of potassium. The 
 serum of grown-up animals contains more salts than that of the young ; the serum of 
 the calf, however, contains 1-12 % salts, while that of the cow contains 0'99, and of the 
 ox 0'87 % (Nasse and Poggiale). The blood of cats, goats, and sheep, contains the 
 most salts; of birds, men, and pigs, less; and of dogs and rabbits the least. Arterial blood 
 serum is somewhat richer in salts than venous, and the serum of portal blood contains 
 considerably more than that of the jugular vein. The kind of nourishment has great 
 influence on the amount of salts, and of their several constituents. Plouviez and Pog- 
 giale found that in the blood of animals to whose food common salt had been added 
 for several months, the percentage of salt rose from 0-44 to 0*64, an increase due chiefly 
 to chloride of sodium. The amount of salts is also greatly influenced by disease, being 
 particularly small in violent inflammations, and increasing in typhus, &c. Weber 
 found 1-19 % silica in the ash of bullock's blood. 
 
 The amount of salts, exclusive of iron, in man's blood = 0728 %, woman 0-896, 
 dog 0713 %. Some chemists think they have detected manganese in blood, but its 
 presence is doubtful. Millon found copper in the blood of soldiers whose food had 
 been prepared in copper vessels, and others have detected traces in the blood of men 
 and beasts. It is said always to occur in the ash of the blood of Limulus Cyclops. 
 Millon also detected lead in blood. 
 
 ANALYSIS OF BLOOD. The amount of water in blood is easily estimated by evapo- 
 rating a weighed quantity, and drying the residue at 120 130 C. 
 
 To determine the fibrin, the blood, as it runs from a vein, is received in a tared 
 vessel, and stirred for 5 to 10 minutes with a glass rod, the weight of which is in- 
 cluded in the tare, till the fibrin is completely separated. The blood, together with 
 the separated fibrin, is then weighed, strained through linen, and the fibrin which 
 remains thereon is placed for some time in water, then dried, well boiled with alcohol 
 and ether, to free it from fat, and weighed after drying at 120 C. (Becquerel and 
 Ho die r). Another method of estimation is to leave a weighed quantity of blood to 
 coagulate at rest, tie up the clot in a fine linen bag, after it has contracted as much 
 as possible, knead it first by itself, afterwards with water, and treat the residue as 
 above. (Scherer.) 
 
 Estimation of Albumin and other Matters coagulable by Heat. A weighed quan- 
 tity of the blood, slightly acidulated with acetic acid, is added by drops to boiling 
 water, the liquid is poured through a weighed filter, and the coagulum collected 
 thereon ; it is then washed on the filter with boiling water, and dried, first at a gentle 
 heat, afterwards at 120 to 130 C. The residue may be freed from fat by treatment 
 with boiling ether. If the blood had not been previously freed from fibrin, the weight 
 of that substance, determined as above, must be deducted from the total weight of the 
 coagulum. 
 
 Estimation of the Extractive Matter. The filtrate obtained in the last determination 
 is evaporated on the water-bath in a tared platinum basin, the residue dried at 120 C., 
 weighed, and burnt in a muffle at as low a heat as possible. The weight of the ash, 
 deducted from that of the total dried residue, gives approximately the amount of ex- 
 tractive matter. 
 
 Estimation of Fat. A quantity of blood (which need not be weighed) is dried at 
 100 C., the residue is pulverised and dried at 120, and a weighed portion thereof is 
 treated with ether in a flask : the ether is passed through a small filter into a tared 
 platinum capsule; and the treatment of the residue with ether is repeated several times. 
 The collected ethereal solution is carefully evaporated, and the residue dried at 100 C. 
 As the weight of the solid constituents of the blood has been previously determined, 
 the quantity of blood from which this amount of fat has been obtained may be cal- 
 culated from that of the residue which was subjected to treatment with ether. 
 
 Estimation of Mineral Constituents. A weighed quantity of the blood is dried, 
 mixed with ignited carbonate of sodium, then dried and incinerated in the muffle at 
 the lowest possible temperature. (See ASH OF ORGANIC BODIES, p. 418.) 
 
 Separate Estimation of the Serum and Coagulum, with their Constituents. The 
 fresh blood is collected in a tared cylindrical vessel, having a ground edge, and not 
 too shallow ; it is covered with a glass plate and left to stand till the coagulation is 
 complete, after which the edge of the clot is detached from the side of the vessel by 
 means of a needle. The blood is then weighed, and after the clot has contracted as 
 much as possible, the serum is poured off, and the quantity of albumin, &c., contained 
 in it is determined as above described. The clot and the inner surface of the vessel 
 are then freed from serum as completely as possible by wiping with bibulous paper, 
 and the clot is weighed on the vessel. This weight, deducted from the total weight of 
 the blood, gives the proportion of serum. 
 
 The clot contains the blood-corpuscules, the fibrin, and a certain quantity of serum ; 
 the amount of water contained in it maybe determined by drying at 120 to 130 C., 
 
BLOOD. 
 
 611 
 
 but there is no known method of directly estimating the amount of the blood-cor- 
 puscules. Prevost and Dumas estimated it approximately on the assumption that the 
 water contained in the clot is all due to adhering serum, and accordingly deducting 
 from the weight of the dried clot an amount of serum-constituents corresponding to the 
 quantity of water in the clot, together with the amount of fibrin separately determined. 
 As, however, the blood-corpuscuLes themselves contain water, this method necessarily 
 makes the quantity of dry corpuscules too small. 
 
 According to C. Schmidt, the clot contains a quantity of serum amounting to | of its 
 volume, and the weight of the moist blood-cells is four times as great as that of the 
 dry clot, as determined by the method of Prevost and Dumas. Hence, when the con- 
 stituents of the serum and coagulum have been determined as above, and from the 
 weight of the coagulum, a deduction is made of the quantity of serum-constituents 
 corresponding to | of the weight of the moist coagulum, the composition of the cor- 
 puscules may be calculated. 
 
 The separation of hsematin from globulin cannot be effected ; but if the quantity of 
 iron in the dry coagulum be determined, the amount of blood-pigment may be cal- 
 culated on the supposition that this pigment contains 6 '64 per cent, of iron. (S t r e c k e r, 
 Handw. d. Chem. ii. [2] 115). 
 
 1000 pts. Blood-corpuscles contain : 
 Water . $ . 
 Solid constituents : 
 
 Density .... 
 
 Hsematin .... 
 Globulin and membrane of cor- 
 puscules .... 
 
 Fat. 
 
 Extractive matter . 
 
 Mineral matter (without iron) . 
 
 Chlorine .... 
 
 Sulphuric acid 
 
 Phosphoric acid . 
 
 Potassium .... 
 
 Sodium .... 
 
 Oxygen .... 
 
 Phosphate of calcium . 
 
 Phosphate of magnesium 
 
 Mean Composition of Male and Female Blood (Becquerel and Kodier). 
 
 Male Female. 
 
 Density of defibrinated blood . . . 1060-00 1017'50 
 
 Density of serum 1028-00 1027'40 
 
 Water 779'00 791-10 
 
 Fibrin -2-20 2'20 
 
 Fatty matters 1-60 1-62 
 
 Serolin 0'02 0'02 
 
 Phosphorised fat 0'49 0-46 
 
 Cholesterin 0'09 0'09 
 
 Saponified fat 1-00 1'04 
 
 Albumin 69-40 70*50 
 
 Blood-corpuscules 141-10 127*20 
 
 Extractive matters and salts . . . 6'80 7*40 
 
 Chloride of sodium 3'10 3-90 
 
 Other soluble salts 2-50 2'90 
 
 Earthy phosphates 0-33 0'35 
 
 Iron 0-57 0-54 
 
 1000 pts. Blood contain (Schmidt) : 
 
 da: 
 
 688-00 
 
 1000 pts. Serum contain : 
 Water . . 
 
 902-90 
 
 312-00 
 1-0885 
 16-75 
 
 Solid constituents . . . 
 Density .... 
 Fibrin 
 
 97-10 
 1-028 
 4-05 
 
 282-22 
 
 Albumin .... 
 
 78-84 
 
 2-31 
 
 Fat 
 
 1-72 
 
 2-60 
 8-12 
 1-686 
 0-066 
 1-134 
 3-828 
 1-052 
 
 Extractive matter 
 Mineral matter . 
 Chlorine 
 Sulphuric acid 
 Phosphoric acid 
 Potassium 
 
 3-94 
 8-55 
 3-644 
 0-115 
 0-191 
 3-323 
 3-341 
 
 0-667 
 
 
 0-403 
 
 0-114 
 0-073 
 
 Phosphate of calcium 
 Phosphate of magnesium 
 
 0-311 
 0-222 
 
 
 - Man. 
 
 Woman. 
 
 Dog. 
 
 
 513*02 
 
 
 
 
 486*98 
 
 
 
 
 
 
 
 KB 2 
 
612 
 
 BLOWPIPE. 
 
 Salts in 1000 pts. : 
 
 
 Cor- 
 puscles. 
 
 Serum. 
 
 Cor- 
 puscles. 
 
 Serum. 
 
 Cor- 
 puscles. 
 
 Serum. 
 
 
 0-132 
 
 0.281 
 
 0-157 
 
 0-217 
 
 0-309 
 
 0-502 
 
 
 3-679 
 
 0-359 
 
 3-414 
 
 0-447 
 
 0-557 
 
 0-118 
 
 
 
 0-546 
 
 
 5-659 
 
 2-485 
 
 5-342 
 
 
 2-343 
 
 
 2M08 
 
 
 
 
 
 D'633 
 
 0-271 
 
 
 0-443 
 
 2-803 
 
 0-311 
 
 
 
 
 0-857 
 
 
 
 
 
 0-341 
 
 4 532 
 
 2-205 
 
 1-074 
 
 0-861 
 
 1-726 
 
 Phosphate of calcium 
 Phosphate of magnesium .... 
 
 0094 
 0-060 
 
 0-298 
 0-218 
 
 J.0-218 
 
 0-550 
 
 110 
 
 0-841 
 
 Fig. 101. 
 
 C. E. L. 
 BLOODSTONE. A variety of JASPER (q. v.} 
 
 BLOWPIPE. An instrument for directing a stream of air through a flame, either 
 by blowing with the mouth or with bellows. The flame of a candle, of a lamp with 
 a simple wick, or of an ordinary gas-jet, consists of three parts. The dark central 
 portion immediately surrounding the wick or burner, consists of combustible gaseous 
 matter, not yet burned ; this is surrounded by a highly luminous cone, which deposits 
 soot on a cool body held within it ; and outside of all is a thin pale blue envelope 
 which gives little light, but has a very high temperature. It is here that the combus- 
 tion is most complete, the carbon and hydrogen finding sufficient oxygen to convert 
 them into water and carbonic acid. But in the middle luminous cone, the supply of 
 oxygen is not sufficient for complete combustion, and consequently the hydrogen, 
 which burns most easily, takes up the whole or the greater part of it, while the carbon 
 is set free in the form of minute solid particles. If now a jet of air be directed through 
 the middle of the flame, a double combustion takes place, the combustible matter 
 uniting on the outside with the oxygen of the air, and in the interior with that which 
 is supplied by the blast. In this manner, an intensely hot flame is produced, appli- 
 cable for fusions, reductions, and a variety of operations in chemical analysis ; and 
 likewise for soldering metals and working glass. 
 
 The best and cheapest form of the mouth-blowpipe for chemical purposes, is that in- 
 vented by Black. It consists of a tube of tin - plate ( fig. 101), about 7 inches long, and f of 
 
 an inch broad, tapering to | of an inch, where a s'null 
 mouth-piece is soldered. At the wide end a is 
 inserted a small cylindrical tube of brass, about 2 
 in. long, supporting the nozzle, which may be of 
 brass or platinum. 
 
 The tube is slightly conical at the end where 
 the jet is fixed, and the latter is thus made to fit 
 on without a screw, which would soon be injured 
 by the high temperature to which it is exposed, 
 and would then be difficult to remove for the 
 purpose of cleaning. The nozzle is drilled from a 
 solid piece of metal, and in the form shown at b in 
 the figure. One of the chief excellencies of this 
 form of blowpipe, is the efficient manner in which 
 it condenses and retains the moisture of the breath, 
 and prevents its projection on the heated assay. 
 The blowpipe may also be provided with a move- 
 able trumpet- shaped mouthpiece, against which the 
 lips, partially open, may be pressed during the act 
 of blowing ; in this manner, a strong blast may be 
 kept up for a considerable time with very little 
 fatigue. The use of such a mouthpiece is strongly 
 recommended by Plattner in his valuable treatise 
 on the blowpipe ; but it is scarcely necessary, ex- 
 cepting when the blast has to be kept up for a long 
 time, as when the blowpipe is used for quantitative 
 analysis. 
 
 To nse the mouth-blowpipe with success, it is necssary to acquire the art of keeping 
 up a steady blast of air for some time. For this end, the air must be supplied from 
 the mouth, not directly from the lungs, which could not, without fatigue, afford a 
 sufficient stream. The mouth-piece of the instrument being placed between the lips, 
 the mouth is to be filled with air till the cheeks become distended as in playing on a 
 wind instrument. The current of air is then forced through the tube by the action of 
 the muscles of the cheeks, and during the blast, the communication between the chest 
 
BLOWPIPE. 613 
 
 and mouth is closed, respiration being carried on through the nostrils. The mode of 
 effecting this is difficult to describe, but the right method of blowing is easily acquired 
 by a little practice. 
 
 The quality and intensity of the flame vary considerably according to the strength 
 and direction of the blast. If the nozzle of the blowpipe is inserted into the middle of 
 the flame, a little above the wick, as shown in fig. 102, 
 an elongated flame is produced, consisting of an outer f>jg f 102. 
 
 and an inner cone, the former having a yellow, the latter 
 a blue colour. The outer flame is an oxidising flame. 
 An oxidable substance, such as lead or copper, placed 
 at or just beyond the point a of this flame, is strongly 
 heated in contact with the oxygen of the air, and is 
 therefore brought just into the condition for taking up 
 oxygen. *The greatest heat is at the point of the inner 
 flame, the combustible gases being there supplied with 
 just the quantity of oxygen required to consume them ; 
 and between this and the point of the exterior flame, is 
 a quantity of combustible manner, very hot, but not 
 
 yet burned, and therefore disposed to take oxygen from any compound containing that 
 element. This part of the flame is therefore a reducing flame. A piece of ordinary 
 glass containing lead, turns black and opaque when heated in this part of the flame, 
 in consequence of the reduction of the lead ; but by afterwards heating it in the outer 
 flame, the lead is reoxidised, and the transparency restored. 
 
 But the reducing power of a flame produced in the manner just described, is not 
 very great, as any one may convince himself by trying to reduce oxide of copper or 
 oxide of tin in it without the aid of a reducing agent. The flame is for the most part 
 an oxidising flame, especially if the aperture of the blowpipe is large and gives a good 
 supply of air. To obtain a good reducing flame, it is necessary to use a blowpipe with 
 a small aperture, and to adjust the point, not within, but just outside the flame, and 
 to blow rather over than through the middle of the flame. In this manner, the flame 
 is less altered in its general characters than in the former case, the chief 
 part consisting of a large and luminous cone, containing a considerable Fig. 103. 
 quantity of free carbon in a state of intense ignition, and just in the 
 condition for taking up oxygen. 
 
 Substances to be heated in the blowpipe flame, are supported, some- 
 times on charcoal, sometimes in spoons or forceps made of platinum, 
 or on platinum foil or wire, sometimes on small capsules made of clay 
 or bone-earth. Charcoal is used chiefly in experiments of reduction. 
 The substance to be heated is placed in a small hole scooped in the 
 side of the charcoal, not at the ends, because in the latter position, it 
 is more likely, when in the fused state, to sink into the pores of the 
 
 charcoal. Clay basins are chiefly used in the quantitative assaying , . 
 
 of ores. They are made of fire-clay kneaded into a stiff paste with \^_^/ 
 water, pressed into shape in a box-wood mould (fig. 103), then dried 
 
 and calcined. Instead of these, however, very thin porcelain basins, ' -" 
 
 which may be procured ready made, may be used with advantage. 
 Basins or cupels of bone-earth made in a similar manner, are used for cupelling silver 
 and gold with lead. The oxide of lead formed in the process, sinks into the porous sup- 
 port leaving the silver or gold in the form of a metallic button. 
 
 BLOWPIPE ANALYSIS. The blowpipe is an indispensable instrument in qualitative 
 analysis, as it serves to recognise the presence of many substances with greater facility 
 and certainty than could be obtained by analysis with liquid reagents, especially when the 
 quantity of substance to be operated on is but small. Generally speaking, however, it 
 is not safe to trust to the indications of the blowpipe alone, inasmuch as many substances 
 give but indistinct reactions when submitted to this mode of examination, and are apt 
 to be completely overlooked when present together with others whose indications are 
 more decided. In a mixture of iron, nickel, and cobalt, for example, it would be 
 scarcely possible by the blowpipe alone to recognise anything but cobalt, even though 
 that metal might be present in small proportion only as compared with the others. It 
 is best, therefore, to use the blowpipe, and in general, the mode of analysis by the dry 
 way, as a means of determining the general character of a compound or mixture, and 
 detecting certain of its constituents, and thus obtaining an indication of the best 
 mode of proceeding with the more complete analysis by the wet way. 
 
 A concise account of the behaviour of the several elementary bodies, and their 
 principal inorganic compounds when heated per se, and with certain reagents, is given 
 in the article ANALYSIS (!NOEGANIC), (p. 213) ; and these characters will be described 
 in greater detail in treating of the several elements and compounds. The table on 
 
 R B 3 
 
614 
 
 BLOWPIPE. 
 
 Behaviour of Metallic Oxides before the Blow- 
 
 A clear bead is formed by fusing the flux on a loop made at the end of a platinum- wire : the bead is 
 
 in the reducing flame, it is sometimes advisable to employ charcoal instead of platinum-wire. The 
 
 employed, In this table h. signifies hot ; c. cold ; supers, that the bead is super- 
 
 Colour 
 of the 
 Bead. 
 
 With. Microcosmic Salt. 
 
 / 
 In outer or oxidising Flame. 
 
 \ 
 In inner or reducing Flame. 
 
 Colour- 
 less. 
 
 Silica swims undissolved. Alumina ', Stan- 
 nic oxide. All Alkaline earths, and 
 Earths (supers, opaque). Tantalic, Colum- 
 bic, Titanic, Tungstic anhydrides; Zinc-, 
 Cadmium-, Lead-, Bismuth-, Antimony- 
 oxides not sat. : (supers, yellowish). 
 
 Silica swims undissolved. Alumina. All 
 alkaline earths and earths (supers, opaque). 
 Ceric, Didymic, Manganic, Stannic oxides. 
 
 Yellow 
 or 
 brownish. 
 
 h. not sat. Ferric and Ceric oxides, h. Va- 
 nadic anhydride, Uranic oxide, Oxide of 
 Silver, c. Nickel-oxide. 
 
 h. Ferric oxide (reddish), Titanic anhyd. 
 
 Red. 
 
 h. Nickel-oxide, h. supers. Ferric and 
 Ceric oxides. 
 
 h. Ferric oxide, c. Titanic and Tungstic 
 anhydrides containing iron (blood-red). 
 Cupric oxide. 
 
 Violet 
 or 
 Amethyst. 
 
 Manganic and Didymic oxides. 
 
 c. Titanic anhydride. Columbous anhy- 
 dride (not sat.). 
 
 Blue. 
 
 Cobalt-oxide, c. Cupric oxide. 
 
 Cobalt-oxide. Tungstic anhydride. Ni- 
 obous anhydride (supers.) 
 
 Green. 
 
 h. Cupric oxide, Molybdic anhydride, 
 Ferric oxide containing cobalt or copper. 
 Chromic and Uranic oxides. 
 
 Chromic and Uranic oxides, Vanadic and 
 Molybdic anhydride. 
 
 Grey and 
 Opaque. 
 
 
 c. Oxides of Silver, Zinc, Cadmium, Lead, 
 Bismuth, Antimony : Tellurous anhydride. 
 
BLOWPIPE. 
 
 615 
 
 pipe with Microcosmic Salt and Borax. 
 
 dipped into the finely-powdered substance under examination, and again heated. In heating 
 colour of the bead frequently varies with its temperature, and with the quantity of oxide 
 saturated with oxide ; not sat. that it is not completely saturated with oxide. 
 
 With Borax. 
 
 s 
 
 In outer or oxidising Flame. 
 
 A 
 
 In inner or reducing Flame. 
 
 Silica, Alumina, Stannic oxide. Supers, 
 opaque : Alkaline earths and Earths, Oxide 
 of silver, Tantalic, Columbic, Tellurous 
 anhydrides. Not sat. : Titanic, Tungstic, 
 Molybdic anhydrides, Zinc-, Cadmium-, 
 Lead-, Bismuth-, Antimony -oxides. 
 
 Silica, Alumina, Stannic oxide. Supers, 
 opaque : Alkaline earths and Earths, Lan- 
 thanic and Ceric oxides, Tantalic anhyd. 
 Manganic and Didymic oxides, h. Cu- 
 pric oxide. 
 
 h. Vanadic anhydride, h. not sat. Ferric 
 and Urania oxides, h. supers. Lead-, 
 Bismuth-, and Antimonious oxides. 
 
 Tungstic anhydride; Titanic, Vanadic, 
 and Molybdic anhydrides (brownish). 
 
 h. Ceric and Ferric oxides, c. Nickel- 
 oxide (red-brown), h. supers. Chromic 
 oxide. 
 
 c. Cupric Oxide (supers, opaque). 
 
 Manganic and Didymic oxides. Nickel- 
 oxide containing cobalt. 
 
 
 Cobalt-oxide, c. Cupric oxide. 
 
 Cobalt-oxide. 
 
 c. Chromic oxide, Vanadic anhyd. h. Cu- 
 pric oxide, Ferric oxide containing copper 
 or cobalt. 
 
 Ferric, Uranic, Chromic oxides, c. Va 
 nadic anhydride. 
 
 
 The same as with microcosmic salt. Also 
 Nickel-oxide t and (supers.) Columbous an- 
 hydride. 
 
616 
 
 BLOWPIPE. 
 
 ff 
 
 Fig. 104. 
 
 page 614 (taken from Conington's " Handbook of Analysis,") exhibits in a convenient 
 form the colours imparted by metallic oxides to borax and microcosmic salt, when 
 heated therewith in the oxidising and reducing flames. [For further details, see 
 " Chemical Manipulation," by C. Greville "Wlliams, London : Van Voorst ; also, espe- 
 pecially for the method of Quantitative Analysis with the blowpipe: Plattner's "Pro- 
 bierkunst mit dein Lothrohre," or the translation of that work "On the Use of the Blow- 
 pipe, &c.," by Dr. Muspratt, London, 1850.] 
 
 TABLE BLOWPIPE. For sealing and bending glass tubes and constructing glass 
 apparatus of various forms, it is convenient to have the blowpipe mounted on a fixed 
 bupport, and when a flame of considerable power is required, the blast must be sup- 
 plied by bellows worked with the 
 
 e foot. A very convenient form ol 
 
 ~ blowpipe for these purposes is that 
 
 A ' . =i-<Z invented by Her ap at h, and repre- 
 
 presented in fig. 104. a is a flexible 
 tube attached to a stopcock b, which 
 communicates with a tube c d, bent 
 at right angles at d, where a T- 
 shaped tube e f g slips on by means 
 of the piece /. The blowpipe jet h i 
 passes into the -longer arm of the 
 T-piece, and fits somewhat tightly ; 
 k I is a second piece of flexible 
 tube terminating in a mouth-piece, 
 or connected with a blowing appa- 
 ratus. On turning on the gas, it 
 passes in the direction marked by 
 the arrows, and is to be inflamed at 
 e. On blowing with the mouth, or 
 by means of a pair of bellows into the 
 tube k I, the ignited gas takes the 
 form of a blowpipe flame of great 
 power, the nature of which is en- 
 tirely under control by means of the 
 stopcock 6, and also by regulating 
 the quantity of air supplied through 
 the tube k I. The T-shaped piece is 
 moveable at /, so that the jet may 
 be directed to any position. The 
 apparatus may be mounted on a heavy foot, and connected with the gas-supply, by 
 means of the flexible tube, so that it can be placed in any required position on the labo- 
 tory table ; or it may be permanently fixed on a table specially devoted to the purpose, 
 and having beneath it a pair of bellows worked by a treadle. 
 
 OXYHYDROGEN BLOWPIPE. The power of the blowpipe flame may be immensely in- 
 creased by supplying it with oxygen gas instead of atmospheric air. The apparatus 
 last described is very well adapted for the purpose, the flexible tube k I being con- 
 nected with a gas-holder containing oxygen. As the oxygen and the combustible gas 
 would meet only at the very place where the combustion is to take place there would 
 be no danger of explosion. Still greater intensity of heat is obtained by a flame com- 
 posed of pure oxygen and hydrogen in the proportions required to form water. Nume- 
 rous forms of apparatus have been contrived for burning this gaseous mixture, the 
 object being so to contrive the jet that the gases shall be there mixed in the exact 
 proportions required, and at the same time to prevent danger of explosion by prema- 
 ture mixture. The best form is that 
 shown in fig. 105, in which A is a 
 brass tube filled with a number of 
 layers of wire gauze pressed closely 
 together, or with a bundle of very 
 thin brass wires placed parallel to 
 the axis of the tube, and firmly 
 wedged together by a stout conical 
 wire driven into the middle, so as to 
 form a collection of extremely narrow 
 tubes. The gases are supplied by 
 the tubes H, connected with gas- 
 holders or loaded caoutchouc baps, 
 one containing oxygen the other hydrogen. To the other end of the brass tube A 
 
 I 
 
 Fig. 105. 
 
BLUE BOHEIC ACID. 617 
 
 is attached a jet, the extremity of which is formed of platinum. The gases mix in 
 the tube A, and pass on through the meshes of the wire-gauze or the interstices be- 
 tween the thin brass wires to the point of the jet, where they are set on fire. The 
 proportions in which the gases are supplied are regulated by stopcocks on the tubes 
 H. The appearance of the flame, which should be a very narrow cone_ of a pale blue 
 colour, indicates when the right proportion is attained, and this having been once 
 determined, the position of the stopcocks may be marked, so as to ensure the right 
 proportion of the two gases in all future experiments. The use of the wire-gauze or 
 bundle of thin wires in the tube A is to supply a mass of good conducting material, 
 which shall prevent the flame from passing backwards through that tube (see FLAME). 
 The heat produced by the oxyhydrogen flame is the greatest that can be produced _by 
 any artificial means, except by the electric current. Thick platinum wires melt in it like 
 wax in the flame of a candle. By itself, however, it gives but little, light ; but any non- 
 volatile and incombustible solid substance held in it becomes intensely luminous. If 
 the point of the flame be directed on the rounded edge of a cylinder of quick lime, a 
 pure white light of dazzling brilliancy is produced, inferior only to the electric light. 
 It is called the Drummond light, and has been used for lighthouses. 
 BXiUE, PRUSSIAN. See CYANIDES OF IRON. 
 
 BZiUE, SAXON*. The best Saxon blue colour may be made with the following 
 composition : mix one ounce of the best powdered indigo with four ounces of sulphuric 
 acid in a glass bottle or flask, and digest it for an hour at the heat of boiling water, 
 shaking the mixture at different times ; then add 12 oz. of water, stir the whole well, 
 and filter when cold. Poerner adds 1 oz. of good dry potash at the end of twenty- 
 four hours, and lets this stand as much longer before diluting with water. The cloth 
 should be prepared with alum and tartar. 
 
 BODENZTE. A mineral related to aUanite, discovered by Kerndt in the oli- 
 goclase between Boden and Mauersberg, near Marienberg in Saxony. Found only in 
 ill-defined prisms [rhombic?] of 110 to 112, without trace of cleavage. Hardness 
 6'5. Specific gravity 3-523. Eeddish or blackish-brown. Streak dirty white. Opaque 
 with vitreous lustre. When strongly heated, it exhibits incandescence like gadolinite. 
 Fusible only on the acute edges. Decomposed by strong acids. Analysis gave : 26 '12 
 SiO 2 ; 10-33 A1 4 3 ; 12-04 Fe 2 ; 17'44 Y 2 ; 10-46 Ce 2 ; 7'56 La 2 ; 1-61 Mn 2 ; 6'32 
 Ca 2 ; 2-33 Mg 2 ; 1-21 K'O ; 0-84 Na 2 ; and 3'01 H 2 : whence may be deduced the 
 formula 6(3M 2 O.Si0 2 ) + 2Al 4 3 .Si0 2 , the water being regarded as basic. Associated 
 with this mineral are found black amorphous grains of another mineral, Maromontite, 
 containing the same elements, but not exhibiting incandescence when heated. (Kerndt, 
 J. pr. Chem. xliii. 219, 228.) 
 
 BOG-BUTTER. A fatty substance found in the peat-bogs of Ireland. It was 
 first examined by Luck (Ann. Ch. Pharm. liv. 125), afterwards more exactly by 
 Brazier (Chem. Gaz. [1852], 375). It is very soluble in alcohol, and crystallises 
 from the solution in a network of slender needles. It melts at51C. (Luck), the 
 crude fat at 45, but after repeated crystallisation from alcohol and then from ether, 
 at 52 to 52-7 (Br azi e r). It gives off the odour of acrolein when heated. By saponi- 
 fication with potash, it yields an acid, Butyrolimnodic acid (Bogbuttersaure), to which 
 Luck assigned the improbable formula CH 33 4 ; but according to Brazier, this acid 
 has the same composition as palmitic acid, CH 32 0\ or C 16 H 32 2 , and melts at 53 C. 
 BOG-HEAD COAXi. See COAL. 
 BOG-ORES. See IKON. 
 
 BOHEXC ACXB. C 7 H 10 8 = C 7 H 8 4 .H 2 .0 2 . An acid occurring in small quantity 
 in black tea, together with quercitannic acid (Eochleder, Ann. Ch. Pharm. Ixiii. 
 202.) To prepare it, a decoction of black tea is precipitated at the boiling heat with 
 acetate of lead ; the filtered liquid is left to stand for twenty-four hours, and again 
 filtered to separate a small sediment ; the clear solution is mixed with a quantity of 
 ammonia sufficient to neutralise the acid reaction ; the yellow precipitate stirred up 
 with absolute alcohol, and decomposed by sulphuretted hydrogen ; and the filtrate left 
 to evaporate in vacuo over oil of vitriol. The residue is dissolved in water, and the 
 solution is left to evaporate in vacuo, then dried at 100 C., this treatment being repeated 
 three times, and the residue finally left for three weeks in vacuo. 
 
 The acid when pulverised is of a pale yellow colour, Like quercitannic acid. Melts 
 at 100 C. into a mass which draws out into threads. It cakes together when exposed 
 to the air, even for a few minutes, and deliquesces very quickly. Colours ferric 
 hydrochlorate brown, without precipitation. Dissolves in all proportions in water and 
 in alcohol. 
 
 By dry distillation, it yields a light charcoal, and a distillate which smells of acetic 
 acid and blackens iron 'salts. The aqueous and alcoholic solutions decompose when 
 evaporated in contact with the air. The acid is dibasic, the formula of its normal 
 salts being C 7 1F0 4 .M 2 .0 8 . 
 
618 BOLE BOLETUS. 
 
 The barium-salt, C 7 H 8 Ba 2 6 + H 2 0, is obtained as a yellow precipitate by mixing 
 the solution of the acid in aqueous alcohol, with a slight excess of baryta- water. The 
 normal lead-salt, C 7 H 8 Pb 2 6 + H 2 0, is obtained by mixing the alcoholic solution of 
 the acid, after concentration over potash in vacuo, with alcoholic acetate of lead, wash- 
 ing the precipitate with alcohol, and drying at 100 C. It is white, with a tinge of 
 grey. A basic lead-salt, C 7 H 8 Pb 2 6 .Pb 2 0, is obtained by precipitating the aqueous 
 solution of the acid with an ammoniacal solution of acetate of lead. It forms an egg- 
 yellow precipitate. (Kochleder.) 
 
 BOXXiXNG POINT. See HEAT. 
 
 BOIiE. A massive mineral, having a perfectly conchoidal fracture, a glimmering 
 internal lustre, and a shining streak. Its colours are yellow-red, and brownish-black. 
 It is translucent or opaque ; soft, so as to be easily cut and to yield to the nail. It 
 adheres to the tongue, has a greasy feel, and falls to pieces in water. Specific gravity 
 1-4 to 2. It may be polished. If it be immersed in water after it is dried, it falls 
 asunder with a crackling noise. It is a hydrated silicate of aluminium, in which the 
 aluminium is more or less replaced by iron (ferricum). 
 
 The following are analyses of bole : 
 
 SiQ2 Al<03 Fe<03 Ca'O Mg'O R2Q H'O 
 
 41-9 20-9 12-2 _ 24-9 = 99'9 (Wackenroder) 
 
 42-00 24-04 10-03 0'52 0-43 24-03 = 10P05 (Lowig) 
 
 41-05 25-03 8-09 0'45 0'50 _ 24-02=3 99' 14 
 
 4200 20-12 8-53 2'81 201 0'50 24-00= 99'97 (Zellner) 
 
 4592 22-14 390 25-86 = 97-82 (Rammelsberg) 
 
 47-03 18-46 6-36 I'OO 0'90* 25-28 = 99'03 (Thomson) 
 
 a, from Sasebiihl, near Gottingen ; b, from Ettinghausen ; c, from Cap de Prudelles ; 
 d from the Brechte Berg in Silesia. The composition of these specimens agrees nearly 
 with the formula 4M 4 O s .9Si0 2 .18H 2 0, which, by substituting m = |M, maybe reduced 
 to 7n 8 H 4 Si 3 12 + 4aq ; e, from Stolpen in Saxony, is represented nearly by the formula 
 Ca 2 0.2Al 4 3 .4Si0 2 + 4aq = (Ca 2 a/! 12 H 2 )Si 4 16 + 3aq ; /, from the Giant's Causeway 
 in Ireland, is nearly M 4 3 .3Si0 2 + 6aq, which may be reduced to (m 2 H 2 )Si0 4 + aq. 
 All these are formulae of orthosilicates. (Bammelsberg 1 s Mineralchemie, 578; Dana, 
 ii. 252.) 
 
 EOXaOGUZAIT STONE. Lemery reports that an Italian shoemaker, named 
 Vincenzo Casciarolo, first discovered the phosphoric property of the Bolognian stone. 
 It is the ponderous spar, or native sulphate of baryta. If it be first heated to ignition, 
 then finely powdered, and made into a paste with mucilage, and this paste, divided 
 into pieces a quarter of an inch thick, and dried in a moderate heat, be exposed to 
 the heat of a wind furnace, by placing them loose in the midst of the charcoal, a 
 pyrophorus will be obtained, which, after a few minutes' exposure to the sun's rays, 
 will give light enough in the dark to render the figures on the dial-plate of a watch 
 visible. U. 
 
 BOIiETIC ACID. The name given by Braconnot to the acid existing in Boletus 
 pseudo-igniarius, since shown by Bolley and Dessaignes to be identical with fumaric 
 acid. 
 
 BOXiETUS. A genus of mushroom, of which several species have been subjected 
 to chemical examination by BraconnotandBouillon La Grange (Ann. Chim. Ixxx. 
 272) ; and more recently by Bolley, (Ann. Ch. Pharm. Lxxxvi. 44), and Dessaignes 
 (Compt. rend, xxxvii. 780). 
 
 The chief constituents of these fungi are extractive matter, nitrogenous principles, 
 the so-called fungin (q. #.), sometimes mannite, perhaps also fermentable sugar and 
 certain organic acids, called fungic and bolctic acids by Braconnot, but probably con- 
 sisting, according to Dessaignes, of malic or fumaric acid. The ash contains potash, 
 lime, magnesia, phosphoric acid, &c. The species which have been examined are 
 Boletus bovinus (Crell's Chem. Ann. 1785, p. 280), B. igniarius (Ann. Chim. li. 75), 
 B. juglandis (ibid. Ixxxvii. 226), B. laricis (ibid. Ixxx. 272), B. sulphureus and B. 
 viscidiis (TrommsdorfFs 1ST. Journ. ix. 240). 
 
 Boletus laricis, is used on the continent in medicine under the name of agaric. It 
 is in white, light, friable pieces, the outside of which is like dark-coloured leather. Its 
 taste, at first sweetish, soon becomes bitter and acrid. Its infusion in water is yellowish, 
 sweet tasted, and reddens vegetable blues. 
 
 Boletus igniarius is found in most countries, and particularly in the Highlands 
 of Scotland, on the trunks of old ash and other trees. The French and Germans pre- 
 pare it abundantly for making tinder, by boiling in water, drying, beating it, steeping 
 it in a solution of nitre, and again drying it. In France it is called amadou, in this 
 country German tinder. It has been recommended in surgery for stopping haemor- 
 rhage from wounds. It imparts to water a deep brown colour and an astringent taste. 
 
 * Chloride of sodium. 
 
BOLORETIN BONE. 619 
 
 BOIiORSTXHT. A resin of earthy aspect, found in the fossil fir-wood of Danish 
 peat-bogs, and in the needles which fall from the growing trees. The fresh shoots 
 contain but little of it ; but it increases with the age of the needles, and is most abun- 
 dant in autumn and winter. It is prepared by treating with boiling alcohol the grey 
 earthy matter found in hollow fossil fir-stems, and precipitating the foreign matters 
 with acetate of lead. The solution on cooling deposits the boloretin as an earthy 
 mass, which may be further purified by repeated solution in boiling alcohol, with 
 addition of hydrochloric acid to precipitate lead. It is soluble in ether, but not in 
 cold alcohol. Melts at 76 79 C. Its composition is variable, but it appears always 
 to contain the elements of oil of turpentine plus water. It does not, however, yield 
 oil of turpentine when treated with phosphoric anhydride. (Forchammer, Ann. Ch. 
 Pharm. xli. 44.) 
 
 BOLTOWTITE. A variety of olivin, Mg 4 Si0 4 , occurring in crystalline granules, 
 disseminated through limestone at Bolton in Massachussets. Colour ash-grey, wax- 
 yellow, or yellowish-white, with vitreous lustre. Streak white. Transparent or trans- 
 lucent. Specific gravity 3-008 (Silliman); 3'21 (Brush). Hardness in unaltered 
 specimens = 6 or rather greater (Brush). Cleavage distinct in one direction. In- 
 fusible before the blowpipe ; slightly attacked by hydrochloric acid. The following 
 analyses agree nearly with the formula Mg 4 Si0 4 or 2Mg 2 O.Si0 2 : a by J. L. Smith 
 (Sill. Am. J. [2] xviii. 372) ; b by G. J. Brush (ibid, xxvii. 395) : 
 
 SiO 2 Mg 2 Fe 2 Ca 2 A1 4 3 
 
 a. 42-31 61-16 2-77 . . 0-18 1-90 = 98-32 
 
 b. 42-82 54-44 1-47 0-85 trace 0-76 = 100-43 
 
 Analyses by B. Silliman (Sill. Am. J. [2] viii. 15) and v. Hauer (Kenngott's 
 Uebersicht, 1854, 90) gave larger amounts of silica and alumina, and less magnesia ; 
 but the mineral appears to have been but imperfectly decomposed. 
 
 BOLUS. A highly ferruginous clay from Sinope in Asia Minor, containing, ac- 
 cording to Klaproth, 32-0 SiO 2 , 26-5 A1 4 3 , 21'0 Fe 4 3 , 17'0 H 2 0, and 1-5 NaCL 
 
 BONE. (E. v. Bibra, Chemische Untersuchungen iiber die Knochen und Zahne, 
 &c. Schweinfurt, 1844, p. 1258, 289385; E. Fremy, Ann. Ch. Phys. [3] xlvii. 
 47 107; also Trait e de Chimie, par Pelouze et Fremy, 2nd edition, vi. 261; C. J. 
 Lehmann, Physiological Chemistry, iii. 12, and Gmelin's Handbuch, viii. 429.) 
 Bone-tissue is of two kinds, compact and spongy. The long tubular bones of the 
 extremities are formed mainly of the compact tissue, while the flat bones, as those of 
 the skull and pelvis, and the short round bones, consist of an external compact layer, 
 enclosing a mass of the more porous or spongy tissue. The outer surface of bones is 
 covered with a thin membrane (the periosteum}, traversed by great numbers of nerves 
 and bloodvessels, while the inner surfaces of their cavities and channels are lined with 
 a still thinner membrane. These tubes and cavities contain a fatty substance called 
 marrow. The substance of the bone itself exhibits a laminated structure, the indi- 
 vidual layers being concentric with the tubes and channels containing the marrow. 
 These layers consist of an amorphous substance, intersected by cavities, from which 
 proceed innumerable intercommunicating channels. 
 
 The true bony tissue, distinguished from the external and internal membranes, the 
 marrow, and the various fluids contained in the channels and cavities above-mentioned, 
 consists essentially of an organic substance, called bone-cartilage, or ossein, and an in- 
 organic substance, composed mainly of tribasic phosphate of calcium, Ca 3 P0 4 , together 
 with smaller quantities of phosphate of magnesium, Mg 3 P0 4 , carbonate of calcium, and 
 fluoride of calcium. 
 
 If a bone be incinerated without previously reducing it to powder, and washing out 
 the blood and other extraneous fluids contained in its cavities, the ash will likewise 
 contain small quantities of alkaline sulphates, carbonates, and chlorides, and of iron, 
 but these are derived from the liquids just mentioned, and do not properly belong to 
 the bone itself. 
 
 The bone-cartilage or ossein may be separated from the earthy matter by macerating 
 a bone for some time in dilute hydrochloric acid. The calcium-salts then gradually 
 dissolve, the mass becomes translucent and soft, and ultimately the cartilage is left 
 free from mineral matter, and retaining the form of the bone. By boiling in watex', it 
 is converted into gelatin and dissolves, forming a solution clouded by suspended fat 
 and vascular tissue, and solidifying in a jelly on cooling. When freed from these ex- 
 traneous matters by digestion in alcohol and in ether, it is found to have the same 
 proportional constitution as gelatin, as may be seen from the following table, in which 
 the composition of bone-cartilage from various sources is compared with that of pure 
 gelatin (isinglass). 
 
620 
 
 BONE. 
 
 Composition of Gelatin and Bone-cartilage. 
 
 
 Carbon. 
 
 Hydrogen. 
 
 Nitrogen. 
 
 Oxygen. 
 
 
 G-elatin : 
 
 
 
 
 
 
 From Bone 
 
 50-40 
 
 6-64 
 
 18-34 
 
 24-64 
 
 Mulder. 
 
 (fossil) . . 
 
 50-40 
 
 7-11 
 
 18-15 
 
 24-36 
 
 v. Bibra. 
 
 Isinglass . 
 
 50-76 
 
 6-64 
 
 18-32 
 
 24-69 
 
 Mulder. 
 
 Bone-cartilage : 
 
 
 
 
 
 
 From femur of Ox . 
 
 50-13 
 
 7-07 
 
 18-45 
 
 24-35 
 
 v. Bibra. 
 
 Pipa 
 
 50-45 
 
 7-08 
 
 18-21 
 
 24-24 
 
 
 Kib of River Carp . 
 
 50-32 
 
 7*22 
 
 18-42 
 
 24-00 
 
 5J 
 
 -Ox ... 
 
 49-81 
 
 7-14 
 
 17-32 
 
 25-67 
 
 Fremy. 
 
 Calf ... 
 
 49-9 
 
 7-3 
 
 17-2 
 
 25-6 
 
 
 
 Owl ... 
 
 49-05 
 
 6-77 
 
 
 
 
 Bone-cartilage also contains sulphur, which v. Bibra estimates at 0-216 per cent. 
 The chief difference between bone-cartilage and gelatin is, that the latter dissolves 
 easily and immediately in boiling water, whereas the former is insoluble in water until 
 it has been converted into gelatin, which requires long boiling. 
 
 According to Fremy, the" bone-cartilage has likewise the same composition in young 
 and in old animals. Foatal bones, however, do not appear to yield gelatin when boiled 
 with water; or at all events, Schwann (Mikrosk. Unters. 1839, p. 3), could not ob- 
 tain that substance from the bones of a foetal calf, nor Hop pel (Arch. f. pathol. Anat 
 v. 174) from those of a rabbit, down to the last hours of intra-uterine life. In fossil 
 bones, the cartilage is often found to be converted into true gelatin. The cartilage of 
 diseased bones does not appear to differ from that of healthy bones (v. Bibra and 
 others). In the bones of certain water-birds, and in the spines of certain fishes, 
 Fremy found a substance resembling ossein in physical characters, and isomeric with 
 it, but differing from it in not yielding gelatin when boiled with water. 
 
 Quantitative Analysis. The bone is first reduced to fine powder by rasping, then 
 washed with water to remove soluble salts, &c., and digested with ether to remove 
 fatty matters. Care must however be taken not to continue the washing with water 
 too long, as by the prolonged action of water, small quantities of the phosphates of 
 calcium and magnesium are dissolved out, the quantity thus removed increasing as 
 the organic matter of the bone passes more and more into the state of putrefaction. 
 (Wohler.) 
 
 The bone purified as above, is next incinerated in a muffle (p. 418), till it becomes 
 quite white, then moistened with solution of carbonate of ammonium, to restore any 
 carbonic acid that may have been driven off from the lime, and again heated just 
 sufficiently to expel the excess of carbonate of ammonium. The difference between 
 the weight of the dried bone before ignition, and that of the ash, gives the amount of 
 cartilage. 
 
 The analysis of the ash is made for the most part by the ordinary methods (p. 419). 
 The carbonic acid must be estimated by one of the methods given under ALKALI- 
 METBY (p. 117), first in the unignited bone-powder, and afterwards in the ash. The 
 first gives the amount of carbonate of calcium in the bone, and from the difference 
 of the two determinations, the quantity of lime which was in combination with organic 
 acids may be found. The amount of carbonate of calcium cannot be correctly esti- 
 mated by precipitating with carbonate of ammonium the lime which remains in solu- 
 tion after the phosphate of calcium lias been precipitated by caustic ammonia. The 
 adoption of this method in the earlier analyses, led to the incorrect conclusion that 
 the calcium-phosphate contained in bone-earth was 8Ca 2 O.P 2 5 , instead of 3Ca 2 O.P 2 5 . 
 The amount of fluorine in bones has seldom been determined quantitatively, the 
 calcium really existing as fluoride being generally reckoned together with the car- 
 bonate or phosphate. Marc hand, however (J. pr. Chem. xxvii. 83), found in a human 
 thigh-bone 1 per cent., and Heintz (Wien, Akad.Ber. 1849, p. 51), found in a similar 
 bone 2-05 per cent, fluoride of calcium. In fossil bones, the proportion of this salt is 
 often much greater. 
 
 As bone-tissue is very hygroscopic, it is necessary, in comparing the qiiantities of 
 water which different bones retain, after drying in the air at ordinary temperatures, to 
 notice the indications of the barometer and thermometer before exposing the boues to 
 the heat of the water-bath or oil-bath. 
 
BONE. 
 
 621 
 
 The most complete investigations that have been made of the composition of bone, 
 are those of v. Bibra and Fremy. The following table exhibits the percentage of 
 inorganic matter in human bones of various ages, as determined by v. Bibra. 
 
 Name of Bone. 
 
 Percentage 
 of Ash. 
 
 Name of Bone. 
 
 Percentage 
 of Ash. 
 
 Male foetus, 7 months: 
 
 
 Woman, 25 years : 
 
 
 Femur, tibia, humerus . 
 
 59-1 to 59-6 
 
 Femur, tibia, fibula, ulna 
 
 
 Female foetus, 1 months 
 
 64-5 to 65 -4 
 
 os occipitis 
 Humerus 
 
 68-4 to 68-8 
 69-25 
 
 Boy, 2 months : 
 Tibia .... 
 Atlas .... 
 
 65-32 
 64-07 
 
 Clavicule 
 Kib ... 
 Sternum 
 Scapula . 
 
 67-51 
 64-57 
 51-43 
 65-48 
 
 Boy, | year : 
 
 
 Vertebrae 
 
 54-25 
 
 Femur .... 
 
 56-43 
 
 Os innominatum . 
 
 59-97 
 
 Humerus 
 Tibia .... 
 
 58-58 
 56-58 
 
 Man, between 25 and 30 yrs. 
 
 
 Eadius .... 
 
 52-52 
 
 Femur, tibia, humerus, 
 
 
 Ulna .... 
 
 56-51 
 
 ulna .... 
 
 68-0 to 69-4 
 
 Kib .... 
 
 49-30 
 
 Os occipitis . 
 
 68-73 
 
 Scapula .... 
 
 4971 
 
 Kib .... 
 
 63-99 
 
 Boy, 5 years : 
 Femur .... 
 
 67-80 
 
 Woman, 78 years : 
 Femur .... 
 
 66-81 ' 
 
 Tibia .... 
 
 6771 
 
 
 
 Girl, 19 years : 
 
 
 Man, 58 years : 
 
 
 Femur .... 
 
 67-85 
 
 Femur, dense portion 
 
 68-53 
 
 Humerus 
 
 67-71 
 
 spongy portion . 
 
 64-18 
 
 From these results it appears : 1. That the proportion of inorganic matter in bone 
 is smaller in youth than in age, although no regular gradation can be observed. 2. The 
 proportion of inorganic matter is greater in compact than in spongy bone-tissue; 
 greater also in the bones of the extremities than in those of the trunk ; greatest of all 
 in the thigh-bone. It appears, indeed, to be greatest in those bones which are most 
 moved, or have to bear the greatest strain ; this observation is corroborated by the 
 composition of the bones of birds (see below). . 
 
 The different orders of mammiferous animals do not exhibit any essential differences 
 in the proportions of inorganic matter in their bones, the limits being 64 and 75 per 
 cent. The bones of birds contain on the average a larger proportion of inorganic 
 matter than those of mammals, viz. 68-6 to 75-8 per cent. ; those of reptiles rather 
 less, 51*7 to 68-9 per cent. The bones of fishes exhibit great variety in the proportion 
 of mineral matter which they contain, e.g. Bony fishes: eel 51-62 per cent.; cod 
 65-76; salmon 64-37; perch 59-40 per cent. Cartilaginous fishes: Shark 46 -82 per 
 cent.; lamprey 1*66 per cent. 
 
 Fremy's results agree for the most part with those of v. Bibra, excepting in the 
 proportion of organic and inorganic matter in bones of different ages, which, according 
 to Fremy, do not exhibit in this respect any sensible variation. The bone of a foetus 
 was found to yield the same quantity of ash as that of a woman 97 years of age, and 
 the first bony particles that make their appearance in the midst of the cartilaginous 
 mass, which in the foetus precedes the formation of true bone, were found to contain 
 the same quantity of mineral matter as the bone of an adult animal (see table, p. 621). 
 The greater brittleness of the bones in age is attributed by Fremy to the increase in 
 the proportion of the spongy tissue, the thickness of the hard and dense portion of the 
 bones continually diminishing as age advances. 
 
 Fremy's analyses of the bones of animals belonging to different orders show, in 
 accordance with those of v. Bibra, that the bones of mammifers exhibit the same 
 average composition as those of man, the bones of herbivorous quadrupeds, however, 
 generally containing a larger proportion of lime-salts than those of flesh-eaters. The 
 bones of birds have nearly the same proportion of lime-salts as those of herbivorous 
 mammals, and those of reptiles nearly the same as those of carnivorous mammals. 
 The bones of fishes exhibit great diversity of composition, those of bony fishes being 
 very much like those of mamnifers, whereas those of cartilaginous fishes are rich in 
 organic matter, and contaii} but a small proportion of mineral salts. 
 
BONE. 
 
 Comparative Analyses of "Bones belonging to different Orders of 
 
 (Fremy.) 
 
 om. 
 
 Name of Bone. 
 
 Ash per 
 cent. 
 
 Phos- 
 phate of 
 Calcium. 
 
 Phos- 
 phate of 
 Mag- 
 nesium. 
 
 Carbonate 
 of 
 Calcium. 
 
 Male foetus, 4 months ; femur .... 
 6 months ; . 
 Female fcetus, 
 
 61-7 
 62-8 
 63-0 
 
 60-2 
 60-2 
 
 
 
 7 months; humerus 
 
 62-8 
 64-8 
 
 60-8 
 
 
 
 
 64-6 
 
 61-5 
 
 
 
 Woman, 22 years ; scapula .... 
 cranium .... 
 femur .... 
 humerus .... 
 Man ; spongy part of femur .... 
 
 63-3 
 64-1 
 64-6 
 64-1 
 61-0 
 65-0 
 
 60-0 
 57-8 
 
 17 
 
 10-9 
 
 Man, 40 years ; femur .... 
 Woman, 80 
 
 64-2 
 64-6 
 
 56-9 
 60'9 
 
 1-3 
 1-2 
 
 10-2 
 7'5 
 
 81 ,, ,,..... 
 88 
 
 64-5 
 64-3 
 
 58-1 
 57-4 
 
 1-2 
 1-2 
 
 10-0 
 
 9-3 
 
 spongy part of femur . 
 97 femur 
 Egyptian mummy ; femur . 
 
 59-7 
 64-9 
 65-0 
 64-0 
 
 54-0 
 57-0 
 587 
 
 1-2 
 1-2 
 
 17 
 
 7-0 
 9-3 
 5-9 
 
 
 62-0 
 
 
 
 
 Genet 
 
 70-2 
 62-1 
 
 59-0 
 
 1-2 
 
 6-1 
 
 Young lioness ; femur 
 Panther; femur 
 
 64-7 
 65-6 
 63-1 
 
 60-0 
 53-9 
 
 1-5 
 1-5 
 
 6-3 
 9-3 
 
 
 66-3 
 
 587 
 
 1-1 
 
 6-3 
 
 
 71-8 
 
 
 
 
 
 66-8 
 
 62-2 
 
 1-2 
 
 6-6 
 
 
 65-3 
 
 60-0 
 
 2-3 
 
 5-2 
 
 Horse; femur 
 Calf, still-born ; spongy part of femur 
 dense 
 
 70-4 
 61-5 
 64-4 
 69-1 
 
 60-5 
 59-4 
 61-2 
 
 1-2 
 17 
 1-2 
 
 5-2 
 
 8-4 
 
 
 70-7 
 
 
 
 
 
 71-1 
 
 
 
 
 i > >i ... 
 
 71-3 
 70-4 
 
 62-5 
 61-4 
 
 27 
 17 
 
 7-9 
 8-6 
 
 
 70-2 
 
 62-4 
 
 17 
 
 7'9 
 
 Bull; femur 
 
 69-3 
 677 
 
 59-8 
 607 
 
 1-5 
 1-5 
 
 8-4 
 8-1 
 
 
 70-0 
 
 62-9 
 
 1-3 
 
 77 
 
 G-oat; , 
 
 68-0 
 
 58-3 
 
 1-2 
 
 8-4 
 
 Cachalot,, 
 Whale; spongy part 
 Eagle 
 
 62-9 
 57-5 
 70-5 
 
 51-9 
 60-6 
 
 0-5 
 17 
 
 10-6 
 8-4 
 
 
 66-2 
 
 
 
 
 Owl (Grand Duke) 
 
 71'3 
 
 61-6 
 
 1-5 
 
 8-8 
 
 
 70-0 
 
 
 
 
 spongy part 
 
 67-0 
 71-1 
 
 
 
 
 Chicken 
 Turkey 
 
 68-2 
 677 
 
 64-4 
 63-8 
 
 1-1 
 1-2 
 
 5-6 
 5-6 
 
 
 707 
 
 65-4 
 
 
 
 
 70-6 
 
 62-5 
 
 1-5 
 
 10-2 
 
 Thrush 
 
 66-6 
 
 63'0 
 
 
 
 Humming bird ; bones of head 
 - ,, limbs 
 
 55:0 
 59-0 
 
 
 
 
BONE. 
 
 TABLE. continued. 
 
 623 
 
 Name of Bone. 
 
 Ash per 
 cent. 
 
 Phos- 
 phate of 
 Calcium, 
 
 Phos- 
 phate of 
 P Mag- 
 nesium. 
 
 Carbonate 
 of 
 Calcium. 
 
 Teal 
 
 73-5 
 
 68-4 
 
 1-3 
 
 5-6 
 
 
 64-3 
 
 58-0 
 
 1-2 
 
 
 Land tortoise ; carapace 
 Crocodile ; cutaneous bone .... 
 Crocodile 
 
 64-0 
 64-6 
 64-0 
 67'5 
 
 56-0 
 58-3 
 58-3 
 
 1-2 
 trace 
 0-5 
 
 107 
 
 97 
 
 7-7 
 
 Cod 
 Barbel 
 
 61-3 
 60-2 
 
 65-1 
 
 1-3 
 
 7-0 
 
 Sole 
 
 54-0 
 
 
 
 
 Shad 
 
 50' 
 
 
 
 
 Carp 
 
 61-4 
 
 58-1 
 
 1-1 
 
 47 
 
 Pike 
 
 66-9 
 
 64-2 
 
 1-2 
 
 4-7 
 
 Eel 
 
 Tetrodon ; maxillary with teeth 
 Diodon ; spine of the skin .... 
 Shark 
 
 57-0 
 76-0 
 68-8 
 62-6 
 
 56-1 
 
 trace 
 
 2-2 
 
 Ray; cartilage 
 
 30-0 
 65-3 
 
 27-7 
 64-4 
 
 trace 
 trace 
 
 4-3 
 1-3 
 
 Lamprey ; head with teeth .... 
 
 2-2 
 
 
 
 
 Diseased Bones. Bones are subject to several diseases, in nearly all of which 
 the proportion of inorganic matter is found to diminish. In caries, the calcareous por- 
 tion of the bone is destroyed, without alteration of the cartilage, the latter still yield- 
 ing gelatin when boiled with water. In a carious femur, v. Bibra found the 
 proportion of inorganic salts reduced to 38*3 per cent., and in a portion of astragalus, 
 taken from the centre of the caries, it was only 18 - 5 per cent. In osteomalacia and 
 rachitis, the proportion of mineral matter sometimes diminishes to such an extent, that 
 the bones bend under the weight of the body. Marchand found in the femur of a 
 rachitic child 72-20 per cent, cartilage, 7'20 fat, 14'78 phosphate of calcium, 3'0 car- 
 bonate of calcium, 0'80 phosphate of magnesium, and 2-02 sulphate of calcium, chloride 
 of sodium, iron (and loss). In the osteomalacia of adults, the tribasic phosphate of 
 calcium is converted into f -phosphate, 8Ca 2 0.3P 2 5 (Weber), and the bones sometimes 
 contain a free acid. In this disease, and in the rachitis of children, the cartilage is 
 frequently altered in character, so that it no longer yields gelatin when boiled with 
 water. Exostosis is the formation of osseous tumours on the surface of bones ; these 
 tumours likewise contain an excess of cartilage. Sclerosis is the formation of cartilage, 
 and ultimately of true bony tissue within the medullary cavities and canals of the 
 bones, which thus become denser and almost like ivory. Here also the organic matter 
 is generally in excess, and the carbonate of calcium is increased in proportion to the 
 phosphate. In osteoporosis, which is a dilatation of the medullary cavities, &c., either 
 from the excessive development of the medulla, or from the solvent action of fluids 
 infused into the cavities, the mineral matter is also found to disappear more quickly 
 than the organic matter. 
 
 Fossil Bones. When a bone is exposed to the air or buried in the earth, the 
 organic tissue gradually disappears, while the calcareous salts remain. In buried 
 bones, the tissue likewise becomes incrusted with various substances derived from the 
 surrounding soil, so that fossil bones often contain considerable quantities of carbonate, 
 sulphate, and fluoride of calcium, silica, &c., according to the nature of the formation 
 in which they are embedded. The proportion of carbonate of calcium sometimes 
 amounts to 67 per cent.^ The silica is in the form of quartz, that is, in the modifica- 
 tion which is insoluble in acids and in dilute alkalis. In some cases, the proportion 
 of tricalcic phosphate remains nearly the same as in the original bone,- whereas in 
 others it is greatly diminished. The proportion of phosphate of magnesium does not 
 vary greatly ; it diminishes, however, to a certain extent when the phosphate of cal- 
 cium is replaced by carbonate of calcium or by siliceous compounds. Many fossil 
 bones still retain a portion of their cartilage, which is sometimes also converted into 
 true gelatin. 
 
624 
 
 BONE-BLACK. 
 
 Analyses of Various Fossil bones. (Fr6my.) 
 
 
 Ash 
 
 per cent. 
 
 Phosphate 
 of 
 Calcium. 
 
 Phosphate 
 of 
 Magnesium. 
 
 Carbonate 
 of 
 Calcium. 
 
 Silica and 
 Fluoride of 
 Calcium. 
 
 Organic 
 Matter. 
 
 Ox, from the caves of Oreston ; 
 
 
 
 
 
 
 
 metatarsal bone, external por- 
 
 
 
 
 
 
 
 tion having the aspect of 
 
 
 
 
 
 
 
 wood 
 
 8O74 
 
 71-1 
 
 1-5 
 
 11'8 
 
 
 10-3 
 
 Internal portion of the same 
 
 
 
 
 
 
 
 very friable 
 
 80-6 
 
 71-5 
 
 1-7 
 
 11-3 
 
 
 11-0 
 
 Spongy portion of the same 
 Rhinoceros, from Sansan(Gers) 
 
 84-2 
 
 633 
 
 1-2 
 
 5-2 
 
 17-2 
 
 8-0 
 
 vertebra? .... 
 
 83-4 
 
 59-0 
 
 
 41-3 
 
 2-6 
 
 trace 
 
 Ribs of the same. 
 
 83-1 
 
 66-8 
 
 
 27'5 
 
 1-4 
 
 trace 
 
 Hyena, from the caves of Kirk 
 
 
 
 
 
 
 
 dale; long bone 
 
 75-5 
 
 720 
 
 1-3 
 
 4-7 
 
 
 20-0 
 
 Rhinoceros ; dorsal vertebrae 
 
 69-5 
 
 25-7 
 
 0'4 
 
 57-5 
 
 8-5 
 
 
 hnmerus . 
 
 73-0 
 
 32-4 
 
 0-4 
 
 64-0 
 
 6-2 
 
 
 teeth 
 
 904 
 
 65-2 
 
 07 
 
 13-8 
 
 14-5 
 
 
 Mastodon; tusk . 
 
 90-4 
 
 56-5 
 
 07 
 
 13-1 
 
 24-3 
 
 
 Bear ; dense part of bones . 
 
 839 
 
 597 
 
 0-4 
 
 23-6 
 
 9-8 
 
 
 spongy part 
 
 76-7 
 
 23-1 
 
 1-2 
 
 67-5 
 
 14-0 
 
 
 Anoplotherium ; caudal ver 
 tebra .... 
 
 84-0 
 
 53-1 
 
 04 
 
 2O4 
 
 19-4 
 
 
 Tortoise ; vertebrae . 
 
 87-0 
 
 61-1 
 
 07 
 
 10-6 
 
 18-6 
 
 
 BONTE-BXiACK. Animal black, Animal charcoal, Bcinschwarz. A product ob- 
 tained by heating bones to redness in close vessels. Large quantities of stinking gas, 
 empyreumatic oil, and volatile alkaloids, are then evolved, and there remains a black 
 mass consisting of an intimate mixture of charcoal containing nitrogen, with the 
 mineral matter of the bone, chiefly phosphate and carbonate of calcium. It possesses 
 the power of abstracting many solid substances from their solutions, and is used on a 
 very large scale as a decolorising agent in the refining of sugar. That it may possess 
 this property in the highest degree, the preparation must be so conducted as to leave 
 the largest possible quantity of carbon in the product, and at the same time to render 
 it very porous. The air must therefore be carefully excluded during the ignition, and 
 the heat must be regulated so as not to cause the mass to cake together or become 
 agglutinated by the fusion of organic substances. The bones should be fresh ; those 
 which have lost much of their organic matter by putrefaction, either in the air or 
 underground, do not yield a sufficient quantity of charcoal. They should be coarsely 
 comminuted and boiled to free them from fat, which would melt and yield a very com- 
 pact charcoal. 
 
 The yield of bone-black varies from 30 to 60 per cent, according to the composition 
 of the bones. The long cylindrical bones of the extremities are best adapted for the 
 purpose ; they yield about 60 per cent of bone-black, containing 1 to 1| carbon to 
 9 pts. phosphate of calcium. Eibs, skulls, and vertebrae yield a smaller quantity, 
 and not of good quality : hence it is better to use them for the preparation of 
 gelatin. 
 
 The carbonisation of bones is performed either in iron cylinders, like those used in 
 the distillation of coal, or in covered pots of cast-iron or crucible-ware, heated in a 
 reverberatory furnace; the latter method yields the best charcoal, but the former is 
 adopted when it is desired to collect the volatile products which are given off. (See 
 BoNE-On-.) (For details and figures of machinery, see Ure's Dictionary of Arts, 
 Manufactures, and Mines, i. 369; Muspratfs Chemistry, i. 315; Handworterbuch d. 
 Chcm. 2 te Aufl. ii. 767). 
 
 Bone-black is extensively used both as a decolorising and deodorising agent ; it 
 likewise removes lime and its salts from their aqueous solutions, and is accordingly 
 used for the purification of highly calcareous waters. In the refining of sugar, it 
 serves to free the syrup both from colouring matter and from lime. It decomposes 
 many metallic salts, sometimes absorbing the oxides or metallic acids, sometimes 
 reducing them. It abstracts iodine, not only from solution, but even from its salts. 
 It likewise removes bitter principles and organic alkaloids from their solutions, and 
 has been recommended as an antidote in case of poisoning by such substances. 
 
 Bone-black which has been used for removing colouring matter and lime from 
 syrup or other liquids, may be revivified, that is, restored to its original state, by the 
 following processes : 1. Treating it with acids to remove the lime. 2. Leaving it to 
 ferment or putrefy, in order to render soluble the organic substances which it JIMS 
 absorbed. 3. Washing. 4. Ignition. (For details, see the works above cited.) 
 
 Bone-black is sometimes used as a pigment; for which purpose it is made into a 
 
y 
 
 BONE-OIL BORACITE. 625 
 
 paste with water, and finely pulverised in a colour-mill. The finest pigment of this 
 kind is ivory-black, which is obtained by the carbonisation of ivory. 
 
 Lastly bone-black is used as a manure, especially for cereal crops, being well adapted 
 for this purpose, both by the phosphoric acid and the nitrogen which it contains. It is 
 chiefly efficacious on soils which still retain a considerable quantity of decayed vege- 
 table matter. 
 
 BONE-GIL. DippePs oil, Animal oil, Oleum animale Dippelii. This oil is obtained 
 in large quantity in the preparation of bone-black, by igniting charcoal in cylinders. 
 Similar products are obtained by the dry distillation of other animal substances. The 
 original Dippcl's oil known in Pharmacy was produced from stag's horn ; but all the 
 animal oil now met with in commerce, is obtained from bones in the manner above- 
 mentioned. It has been made the subject of a series of elaborate investigations by 
 Professor Anderson of Glasgow. (Transactions of the Eoyal Society of Edinburgh, 
 xvi. 4 ; xx. Part II. 247 ; xxi. Part I. 219, and Part IV. 571. Ann. Ch. Pharm. Ixx. 
 32 ; Ixxx. 44 ; xciv. 358 ; cv. 335. Jahresber. f. Chem. 1847-8, p. 651 ; 1851, p. 
 475 ; 1854, p. 488 ; 1867, p. 392.) 
 
 Bone-oil is mainly a product of the decomposition of gelatinous tissue, inasmuch as 
 the bones used for the preparation of animal charcoal are boiled, before ignition, with 
 a large quantity of water, to deprive them of their fat (p. 624). The crude oil is 
 dark brown or nearly black, and has a specific gravity of 0'970. It consists chiefly of 
 a mixture of volatile organic bases, together with smaller quantities of acids and 
 neutral hydrocarbons. 
 
 On subjecting a large quantity of the crude oil to fractional distillation, the first f of 
 the distillate consists of about equal parts of a yellow oil and a watery liquid holding 
 in solution sulphide, cyanide, and carbonate of ammonium, together with small 
 quantities of very volatile organic bases. On supersaturating this watery liquid with 
 sulphuric acid, boiling for a while, then distilling with slaked lime, and immersing 
 sticks of potash in the watery distillate, ammonia is given off with brisk effervescence, 
 and a small quantity of oily bases separates on the surface of the potash-solution. 
 
 The remaining f of the distillate consists of oily bases of various degrees of volatility. 
 On mixing them (together with the small portion of oily bases separated from the 
 watery liquid just mentioned) with excess of dilute sulphuric acid, setting the mixture 
 aside for some days, and frequently shaking it, then separating the strongly acid liquid 
 from the portion of oil still unacted on, and boiling it for some time in a still, an alka- 
 line liquid passes over containing pyrrhol, C'H 5 N, a weak base first noticed by Eunge 
 (Pogg. Ann. xxxi. 65) in bone-oil and in coal-tar, and distinguished by the property of 
 imparting a deep purple-red colour to fir wood moistened with hydrochloric acid. 
 
 The remaining acid liquid, after cooling, is mixed with excess of slaked lime and 
 distilled, and the distillate is treated with solid caustic potash, which separates a 
 quantity of oily bases, while the watery liquid retains in solution ammonia and methy- 
 famine, which are given off on simply distilling the liquid, and may be condensed in 
 dilute hydrochloric acid. 
 
 On submitting to fractional distillation the mixture of oily bases separated by the 
 potash, a number of bases are obtained from 65 to 100 C. belonging to the series 
 C"H> +3 N, viz. ethylamine C 2 H'N, tritylamine C 3 H 9 N, tetrylamine C 4 H H N, and amy- 
 lamine C 5 H 13 H ; and above 115 C. another series of bases are given off belonging to the 
 series OH 2B 5 N, and isomeric with phenylamine and its homologues, viz. : 
 
 Pyridine, C S H 5 N, boiling at 1167C. 
 Picoline, C a H 7 N, 135 
 Lutidine, C 7 H 9 N, 154-5 
 Colliding C 8 II>'N, 180 
 
 The non-basic portion of bone-oil yields by repeated rectification, a liquid boiling at 
 65'5C., which, when exposed to a freezing mixture, separates into two distinct layers. 
 The portions boiling at a higher temperature do not exhibit this property. They con- 
 tain benzene, and probably also homologues thereof, also alcohol-radicles, and nitro- 
 genous compounds which are decomposed by sodium. 
 
 BOMTSDORFFITE. A variety of hydrous dichroi'te (ii. 422). 
 
 BORACITE. Borazite. Borate of Magnesia. A mineral occurring in crystals 
 imbedded in gypsum and anhydrite at Liineberg in Hanover, Segeberg in 'Hoi- 
 stein, and Luneville, La Meurthe, in France. The crystals are monometric ; cubes, 
 rhoraboidal dodecahedrons or tetrahedrons, generally hemihedral combinations with 
 a great number of faces. Cleavage octahedral in traces. Specific gravity = 2'974. 
 Hardness = 7. Lustre vitreous, inclining to adamantine. Colour white, inclining to 
 grey, yellow, and green. Streak white. Sub transparent to subtranslucent. Fracture 
 conchoidal, uneven. Pyro-electric, even when massive. (Dana, ii. 393.) 
 
 Boracite was formerly regarded as a bor;ite of magnesium, 3Mg 2 O.B 2 O s ' containing a 
 VOL. I. S S 
 
626 BORIDES BOKNEOL. 
 
 small quantity of iron ; but recent analyses have shown that it likewise contains chlorine. 
 
 The mean results are as follows : 
 
 Mg 2 O Fe 2 B 2 3 Cl H 2 
 
 30-67 1-62 62-55 7'96 075 (Potyka.) 
 
 30-48 1-38 8-50 (Siewert and Geist.) 
 
 If now the ferrous oxide be reckoned as magnesia (Fe 2 : Mg 2 = 72 : 40) these 
 analyses give respectively 31-57 and 31'25 magnesia; and the results agree nearly 
 with the formula MgCl.(3Mg 2 0.4B 2 3 ), which requires 31'35 per cent. Mg 2 0, 62-50 B 2 3 , 
 and 7'94 Cl. (Kammelsberg's Mineralchemie, p. 254.) 
 
 BORAX. Acid borate of sodium. See BORAXES, under BORON, OXIDE or(p.645). 
 
 BO RIDES. Compounds of boron with metals. See BORON. 
 
 BORVTEENE. Valerene. C'H 16 . A liquid hydrocarbon, isomeric with oil of 
 turpentine, secreted by the Dryabalanops camphora, and holding in solution a solid 
 substance, borneol, or camphor of Borneo. It is also obtained from essential oil of 
 valerian, by submitting that oil to fractional distillation, and heating the first portions 
 of the distillate with hydrate of potassium, which takes up valerol, while borneene 
 passes as a distillate. Solid Bornean camphor distilled with phosphoric anhydride 
 also yields a liquid hydrocarbon having the composition C'H 16 . (See VALERIAN, On OF.) 
 
 Borneene is lighter than water, almost insoluble in that liquid, and smells like oil 
 of turpentine. It turns the plane of polarisation of a luminous ray to the left, but less 
 strongly than oil of turpentine. The product obtained from oil of valerian boils at 
 160 C., that from Borneo camphor at 165. Vapour-density 4*60. It absorbs hydro- 
 chloric acid gas, forming a cyrstalline compound. It appears to oxidise when left in 
 badly closed vessels, and when immersed in water, especially in presence of alkalis, it 
 appears to be converted into borneol (Gerhardt, Traite, iii. 628, 641). (See 
 DRYABALANOPS. ) 
 
 Borneene from Madder Fitsel-oil. The fusel-oil contained in the alcohol produced 
 by the distillation of madder-sugar, yields liquid products when distilled at tempera- 
 tures rising to 230 C., while at higher temperatures Isevo-rotatory borneol sublimes. 
 The former, by digestion with caustic potash, then with chloride of calcium, and repeated 
 fractional distillation, yields a liquid which boils at 160 C., contains 88*23 per cent, 
 carbon and 11-81 hydrogen, has a vapour-density = 4*85, and is therefore probably 
 borneene. Lsevo-rotatory borneol (vid. inf.') distilled with phosphoric anhydride aL;o 
 yields a liquid which appears to be borneene. (Jeanjean, Ann. Ch. Pharm. ci. 94.) 
 
 BORNEO!*. Borneol Alcohol, Solid Camphor of Borneo. C'H 18 O. This sub- 
 stance is extracted from the Dryabalanops cafiiphora, being found in cavities in the 
 trunks of old trees. It is also found in small quantity in moist oil of valerian, being 
 probably formed by hydration of borneene. 
 
 According to Pierlot (Ann. Ch. Phys. ix. 291) the crystals found in oil of valerian 
 are not borneol, but valerian-camphor, C I2 H 20 . 
 
 Borneol is produced artificially by heating common camphor with alcoholic potash, 
 its formation being attended, either with evolution of oxygen : 
 
 C 10 H I6 + H 2 = C'H 18 + ; 
 Camphor. Borneol. 
 
 or with simultaneous production of camphic acid : 
 
 2C 10 H 18 + H 2 = C 10 H I8 + C'H I6 2 . 
 
 Camphor. Borneol. Camphic acid. 
 
 The action takes place slowly at 100 C., more quickly at higher temperatures in sealed 
 tubes. (Berthelot, Ann. Ch. Phys. [3] Ivi. 78.) 
 
 Borneol forms small transparent, colourless, very friable crystals or crystalline frag- 
 ments, having an odour like that of common camphor and of pepper, and a hot burning 
 taste. The crystals appear to be regular six-sided prisms belonging to the hexagonal 
 system. Their alcoholic solution possesses dextro-rotatory power, like that of common 
 camphor. Dextro-rotatory power of natural borneol = 3 3 -40 (Biot), of the artifi- 
 cial = 44-9. Borneol is lighter than water, and insoluble in that liquid, but very 
 soluble in alcohol and ether. Melts at 198 C., and boils at 212, distilling with- 
 out alteration. Gently heated with phosphoric anhydride, it yields borneene, C'H 16 . 
 Boiled with strong nitric acid, it gives off H 2 , and is converted into common camphor, 
 C'H 16 0. With hydrochloric acid it unites without liquefying : the compound is de- 
 stroyed by heat. 
 
 LfBVO-rotatory Borneol. This substance, which is isomeric with ordinary bor- 
 neol, but differs from it in possessing equal but opposite rotatory power, is found in the 
 alcohol produced by the fermentation of madder-sugar, and is obtained by collecting 
 
BORON. 627 
 
 the lamina- which crystallise out on standing, or during fractional distillation. It forms 
 crystalline laminae, or a white powder smelling like pepper and common camphor. It 
 dissolves sparingly in water, and when thrown on the surface of water, spins like 
 common camphor. It dissolves easily in acetic acid, alcohol, and ether. Boiling 
 nitric acid converts it into laevo-rotatory camphor. Distilled with phosphoric anhy- 
 dride or chloride of zinc, it yields a hydrocarbon resembling oil of lemon or bergamot. 
 (Jeanjean, Ann. Ch. Pharm. ci. 94.) 
 
 XSORXUXTZ:. Syn. with ERUBESCITE and with TETRADYMITE. 
 
 BOROCAXiCXTE. Native borate of calcium (p. 643). 
 
 BORON*. Atomic Weight 11. Symbol B. - This element occurs in nature as boric 
 or boracic acid, and in a few minerals, viz. native borax or tincal, boracite, hydro- 
 boracitc, datolite, and botri/olitc, and in small quantities in schorl, apyrite, axinitc, 
 and rhodizite. It never occurs in the free state. Homberg, in 1702, first obtained 
 boric acid from borax, and anhydrous boric acid was decomposed by Gray-Lussac and 
 Thenard in 1808, and immediately afterwards, by Sir H. Davy, into oxygen and boron. 
 
 Boron may be obtained in three different states, viz. amorphous, graphito'idal, and 
 adamantine. (Wohler and Deville, Ann. Ch. Phys. [3] lii. 63.) 
 
 1. Amorphous 'Boron. This is the form in which boron was first obtained. 
 Gay-Lussac and Theuard prepared it by igniting boric anhydride (vitrefied boric acid) 
 in a tube with an equal weight of potassium in small pieces, then boiling the fused 
 mass with very dilute hydrochloric acid, washing with water, and drying. This pro- 
 cess yields, however, but a small product, as it is difficult to deprive the boric acid of 
 all its water, and the remaining quantity oxidises part of the potassium, with violent com- 
 bustion, causing part of the mass to be projected. According to R. D. Thomson (Phil. 
 Mag. [3] x. 419), this inconvenience may be obviated by drying the boric anhydride 
 as completely as possible, mixing it in the state of coarse powder, with twice its 
 weight of potassium, freed as completely as possible from the crust of hydrate which 
 generally adheres to it, and gradually heating the mixture to redness in a glass tube 
 over a lamp. Wohler and Deville mix 60 grammes of sodium in small pieces with 
 100 grammes of finely powdered boric anhydride in an iron crucible, and cover 
 the mixture with about 30 grammes of pulverised and previously ignited chloride of 
 sodium. The crucible is then quickly heated to redness, whereupon a violent reaction 
 takes place, and the whole becomes liquid. It is carefully stirred with an iron rod 
 till no more free sodium or unfused chloride of sodium can be seen, then carefully 
 poured into water acidulated with hydrochloric acid, and washed and dried as above. 
 As the amorphous boron is very apt to run through the filter when washed with pure 
 water, it is best to wash with water containing sal-ammoniac, and then remove that 
 salt by means of alcohol. Another mode of preparing amorphous boron is that of 
 Berzelids, which consists in decomposing perfectly dry borofiuoride of potassium by 
 heating it with an equal weight of metallic potassium in an iron tube closed at both 
 ends. The mixture is first heated merely to the melting point of potassium, then well 
 stirred with an iron rod, and afterwards heated to redness. The decomposition takes 
 place without explosion, and the boron is afterwards separated from the fluoride of 
 potassium, with which it is mixed, by digestion and washing with water containing 
 sal-ammoniac, the latter being finally removed by alcohol. If too little potassium has 
 been taken to produce complete decomposition, the washing is rendered difficult by 
 the remaining borofluoride of potassium, which has but little solubility. Amorphous 
 boron is also formed, together with the other two varieties, in the modes of preparation 
 presently to be described. 
 
 Amorphous boron is a dark-brown or greenish-brown powder, opaque, destitute of 
 taste and smell, and stains the fingers strongly. It is a non-conductor of electricity. 
 In vacuo, or in gases with which it does not unite, it may be raised even to a white 
 heat without melting, or subliming, or undergoing any alteration, excepting that it 
 becomes so dense that it sinks rapidly in oil of vitriol. In the unignited state, it dis- 
 solves, to a very slight extent, in pure water, imparting its colour ; in water containing 
 acids or salts it is insoluble, and indeed such substances precipitate it from its aqueous 
 solution. 
 
 Amorphous boron does not oxidise in the air or in oxygen gas at ordinary tempera- 
 tures, but at about 300 C. it burns in the air with a reddish light, and in oxygen gas 
 with dazzling brightness ; the combustion is in both cases attended with vivid emis- 
 sion of sparks, and in oxygen gas, according to Berzelius, a faint greenish flame is ob- 
 served. The product is boric oxide or anhydride, B 2 3 , the only known oxide of boron, 
 which melts on the surface of the boron and partly protects it from further action. 
 In atmospheric air, according to Wohler and Deville, a small quantity of nitride of 
 boron is formed at the same time. 
 
 ss 2 
 
628 BORON. 
 
 Amorphous boron does not decompose water, even at the boiling heat, but it readily 
 decomposes strong sulphuric acid when heated with it, and nitric acid, even when 
 but slightly concentrated, in the cold, the product in each case being boric acid. At a 
 red heat, it decomposes the carbonates, sulphites, sulphates, nitrites, and nitrates of 
 the alkali-metals, an alkaline borate being formed, and carbon, sulphur, or nitrogen 
 set free. The decomposition is sometimes attended with incandescence and, in the 
 case of nitre, with explosion. It also decomposes many metallic oxides at a red heat, 
 forming a borate, if the oxide is in excess. Heated with hydrate of potassium, it 
 eliminates hydrogen, and forms borate of potassium. It likewise reduces many 
 metallic chlorides and sulphides, e.g. chloride of lead, chloride of silver, and sulphide 
 of lead at a red heat, chloride of boron being formed and escaping as gas (Wohler 
 and Deville). It precipitates metallic gold from a solution of the chloride. When 
 strongly ignited in a current of nitrogen gas, it is converted into white nitride of boron. 
 Heated nearly to redness in a current of nitric oxide gas, it burns brilliantly, forming 
 boric anhydride and nitride of boron. Itdoes notdecompose nitrous oxide. (Wohler 
 and Deville). 
 
 By ignition with aluminium, amorphous boron may be converted into the two other 
 modifications, which remain behind on dissolving out the aluminium by hydrochloric 
 acid. 
 
 G rap hi to 'ida I Boro n. This variety of boron is obtained : 1. By passing gaseous 
 chloride of boron for some time over aluminium in the state of fusion. The metal 
 takes up but a small quantity of boron ; but on breaking it, the boron is found on the 
 fractured surface in copper-coloured crystalline laminae, like graphite in cast-iron ; 
 they may be separated by dissolving out the aluminium with hydrochloric acid. 
 2. By heating 8 pts. of borofluoride of potassium and 5 pts. of aluminium with a flux 
 of 9 pts. chloride of potassium and 7 pts. chloride of sodium to the melting point of 
 silver, in a porcelain crucible, and treating the half fused metallic mass found in the 
 midst of the slag, first with hydrochloric then with hydrofluoric acid. Boron then re- 
 mains in small blackish-grey crystalline scales. 3. By fusing a mixture of 15 pts. boric 
 anhydride, 10 pts. fluor-spar, and 2 pts. aluminium ; or by fusing aluminium with boric 
 anhydride, or better with fused borax and cryolite, and a flux of chloride of potassium 
 and chloride of sodium. A large excess of aluminium, however, is required to obtain 
 but a small quantity of boron. 
 
 Graphitoi'dal boron has a semi-metallic lustre, like graphite or crystalline ferric 
 oxide, but with a distinct tinge of copper-red. When well crystallised, it forms thin six- 
 sided tablets belonging to the hexagonal system ; but it is more generally obtained as 
 a reddish-grey, micaceous powder composed of fine crystalline laminae. It is perfectly 
 opaque. When heated to redness in the air, it does not burn or undergo any apparent 
 alteration. It does not dissolve in acids or in alkalis, but appears to be converted 
 into boric acid by the long-continued action of nitric acid. (Wohler and Deville.) 
 
 Adamantine or Diamond Boron. This is not, strictly speaking, a form of 
 pure boron ; at least, as hitherto obtained, it always contains carbon and sometimes 
 aluminium. To prepare it, 80 grammes of aluminium in lumps are heated with 100 
 grammes of boric anhydride to a temperature at which nickel fuses readily. The 
 mixture is introduced into a crucible of compact charcoal fitted with a charcoal 
 cover and placed within a hessian or black-lead crucible, the intermediate space being 
 filled with charcoal-powder, and the cover fastened on with refractory luting ; and the 
 whole is exposed for five or six hours to the strongest heat of an air-furnace, having a 
 tall chimney and fed with a mixture of coke and coal. On breaking the crucible 
 after cooling, two layers are found, one glassy, consisting of boric anhydride and 
 alumina, the other a metallic iron-grey mass of aluminium, penetrated throughout 
 with crystalline boron. The aluminium is dissolved out by strong soda-ley, iron by 
 hot hydrochloric acid, and the residue is treated with a hot mixture of nitric and 
 hydrofluoric acid, to remove silicium. The crystals of diamond boron thus far purified 
 are still mixed with graphitoi'dal boron and crystalline laminae of alumina ; the former, 
 being light, may be separated by levigation ; the latter only by careful mechanical 
 selection. 
 
 Adamantine boron forms quadratic octahedrons, in which the principal axis is to 
 the secondary axes as 0*577: 1. The crystals vary in colour, from a scarcely per- 
 ceptible honey-yellow to deep garnet-red ; sometimes they are so deeply coloured, pro- 
 bably by amorphous boron, that they appear black. In lustre and refracting power, 
 they are nearly equal to the diamond. Their specific gravity is 2'63. They are ex- 
 tremely hard, always sufficiently so to scratch corundum with facility, and some 
 crystals are nearly as hard as diamond itself. The hardest are obtained by repeatedly 
 pxposing aluminium to the action of boric anhydride at a temperature high enough t<& 
 cause the anhydride to volatilise very quickly. 
 
BORON: BROMIDE CHLORIDE. 629 
 
 Adamantine boron does not fuse, even at the heat of the oxyhydrogen blowpipe, and 
 withstands the action of oxygen even when very strongly heated ; but it is slightly 
 oxidised at the temperature at which the diamond burns, a film of boric anhydride 
 being then formed, which stops further oxidation. Heated on platinum-foil before the 
 blowpipe, it forms a fusible boride of platinum. It is not attacked by acids at any 
 temperature, but when heated to redness with acid sulphate of potassium, it is con- 
 verted into boric acid. It is not attacked by a strong boiling solution of caustic soda, 
 but is slowly dissolved by hydrate or carbonate of sodium at a red heat. Nitre does 
 not appear to act upon it at any temperature. 
 
 Boron unites, as already observed, with oxygen and with nitrogen, also with 
 chlorine, bromine, fluorine, and sulphur. With metals it does not, for the most part, 
 unite readily ; but borides of palladium and platinum are known. The platinum 
 compound is very fusible, so that boron, in either of its modifications, if ignited on 
 
 S'atinum-foil before the blowpipe, instantly perforates the platinum. (Wohler and 
 eville.) 
 
 Boron in all its combinations appears to be triatomic ; the chloride being BC1 3 , the 
 oxide B-0 3 , the hydrate (boric acid) IFBO 3 , &c. 
 
 BORON, BROMIDE OF. BBr 3 . Discoveredby Poggiale in 1846 (Compt, rend, 
 xxii. 124), but first obtained pure by Wohler and Deville (Ann. Ch. Phys. [3] Hi. 
 89.) It is produced by the action of bromine on amorphous boron, or on boric anhy- 
 dride in presence of charcoal. The best way of preparing it is to pass bromine-vapour 
 over heated amorphous boron, previously well dried in a current of hydrogen ; then 
 digest the product for some time with metallic mercury, to remove excess of bromine, 
 and distil. 
 
 Pure bromide of boron is a colourless mobile liquid, of specific gravity 2-69, vola- 
 tilising readily at ordinary temperatures, in colourless, pungent vapours, and boiling 
 under the ordinary atmospheric pressure, at 90 C. Vapour-density (referred to air), 
 by experiment, 878 ; by calculation (2 vol.) = 87. It fumes in moist air, and is in- 
 stantly decomposed by water, with formation of boric and hydrobromic acids. With 
 dry ammonia-gas, it forms a white pulverulent substance, which is converted by water 
 into bromide and borate of ammonium : possibly thus : 
 
 BBr 3 .4NH 3 + 2H 2 = 3NH 4 Br + NH 4 B0 2 . 
 
 BORON*, CHLORIDE OP. BC1 3 . First prepared by Berzelius (Pogg. Ann. 
 ii. 147), afterwards by Dumas (Ann. Ch. Phys. [2] xxxi. 436; xxxiii. 376), more 
 exactly investigated by Wohler and Deville (ibid. [3] Hi. 88). It is formed by the 
 direct combination of chlorine and boron, which takes place at ordinary temperatures, 
 or at a gentle heat ; also by heating boron in hydrochloric acid gas, or a mixture of 
 boric anhydride and charcoal in chlorine gas, and by the action of boron at a red heat 
 on chloride of mercury, lead, or silver. 
 
 To prepare it, amorphous boron, loosely packed in a glass tube, is first freed from 
 moisture by passing dry hydrogen over it at a gentle heat ; the tube is then left open 
 for a few seconds, to allow the hydrogen to escape ; after which, dry chlorine gas is 
 passed through the tube, the action being assisted if necessary, by gently heating the 
 tube in a combustion furnace. Combination then takes place, attended with evolution 
 of light and heat ; and the vapours of chloride of boron are passed through a caout- 
 chouc connecting-tube into a Y-shaped tube, the two upper arms of which are sur- 
 rounded with ice and salt, while the lower arm conveys the condensed liquid into a 
 receiver placed below. The product may be freed from excess of chlorine by digestion 
 with mercury. A small quantity of oxychloride of boron is generally formed at the 
 same time, by the action of a little air or moisture left in the apparatus ; but it con- 
 denses in the cooler part of the combustion-tube. The chloride of boron may be freed 
 from excess of chlorine by digestion with mercury. 
 
 When the vapour of chloride of boron is mixed with hydrogen, as when it is pro- 
 duced by heating boron in hydrochloric acid gas, or with carbonic oxide, as when 
 produced- by the action of chlorine on a hot mixture of boric anhydride and charcoal, 
 it is very difficult to condense ; indeed, chloride of boron was originally regarded as a 
 gas at ordinary temperatures, until Wohler and Deville obtained it in a state of purity 
 by the process above described. 
 
 Pure chloride of boron is a colourless, mobile, strongly refracting liquid, having a 
 specific gravity of 1-35 at 17 C. (? 7) ; it expands very perceptibly by a rise of 1 or 
 2 of temperature. It boils at 17 C. Vapour-density, by experiment = 4'06 4'08 ; 
 by calculation (2 vol.) = 4'07. It fumes in damp air, and is quickly decomposed by 
 water, yielding boric and hydrochloric acids. With alcohol, it forms, with great rise 
 of temperature, hydrochloric acid and borate of ethyl : similar reactions with methylic 
 and amylic alcohols. 
 
 s s 3 
 
630 BORON : DETECTION AND ESTIMATION. 
 
 Ammoneo-chloride of Boron, 3NH 3 .2BC1 3 , is formed, with great evolution of heat, 
 when dry ammonia-gas is passed over chloride of boron. It is a white, finely crys- 
 talline powder, which sublimes unaltered when heated alone, though not so easily as 
 sal-ammoniac. It does not fume in the air, but is decomposed by water, yielding boric 
 acid, chloride of ammonium, and hydrochloric acid : 
 
 2BC1 8 .3NH 3 + 6H 2 = 2H 3 B0 3 + 3NH 4 C1 + 3HCL 
 
 When the vapour of this compound, mixed with ammonia-gas, is passed through a 
 red-hot tube, nitride of boron is produced. 
 
 BORON, CHLORO CYANIDE OP. See CYANOGEN, CHLOBIDE OP. 
 
 BORON, DETECTION AND ESTIMATION OF. Boron almost always 
 occurs in the form of boric acid, and therefore the reactions by which it is detected 
 are best considered in detail in connection with that acid (see page 639). When the 
 acid is in the free state, it is easily recognised by the green colour which it imparts to 
 flame, especially to an alcohol flame, and by its peculiar action on turmeric paper. If 
 the acid is in combination with a base, the compound must first be decomposed in the 
 state of powder by sulphuric acid, and the boric acid extracted with alcohol. Native 
 borates not decomposable by sulphuric acid, must be fused with potash, and then 
 digested with alcohol and sulphuric acid. Another method of detecting boron in 
 minerals is to mix the pulverised substance with 4 pts. of a flux containing 1 pt. 
 pounded fluorspar and 4^ pts. acid sulphate of potassium, made into a paste with a 
 little water, and heat the mixture on a platinum wire in the inner blowpipe flame. 
 As the mass melts, fluoride of boron is given off, and imparts a yellow-green colour to 
 the outer flame. If the quantity of boron present is small, this appearance lasts only for 
 a few seconds, ceasing, in fact, as soon as the fluoride of boron is completely volatilised. 
 
 The green colour imparted to flame is a very delicate test for boron. Before 
 applying it, however, care must be taken to ensure the complete absence of copper, as 
 the salts of this metal impart a very bright green colour to flame. Certain chlorine- 
 compounds also colour flames green, as when hydrochloric acid is dropped into an 
 alcohol flame ; but the green colour thus produced has a decided bluish tinge, which 
 distinguishes it from that produced by boron. Lastly, phosphates moistened with 
 sulphuric acid, also give a faint green colour to the outer blowpipe flame. 
 
 Quantitative Estimation. The exact estimation of boron presents considerable 
 difficulties, as all borates are more or less soluble in water or in alcohol, and boric acid 
 cannot be heated without loss in contact with water. The best mode of direct esti- 
 mation, originally proposed byBerzelius, and perfected by Stromeyer (Ann. Ch. 
 Pharm. c. 82), is to precipitate the boron as borofluoride of potassium, .which is quite 
 insoluble in alcohol of a certain strength. This mode of precipitation, however, is 
 directly applicable only when the boron exists in solution as borate of potassium : any 
 other bases present must first be separated. Borates of the alkaline-earth-metals, 
 earth-metals, or heavy metals, are fused with carbonate of potassium ; and the mass is 
 digested in water, which takes up nothing but borate of potassium, except perhaps a 
 trace of magnesia. Borate of sodium is treated with alcohol and sulphuric acid ; the 
 alcoholic liquid filtered from the sulphate of sodium, is mixed with excess of potash 
 free from silicic and carbonic acids ; and the alcohol is evaporated. The alkaline borate 
 of potassium obtained in either case, is now to be saturated with pure hydrofluoric 
 acid, and the liquid evaporated to dryness in a silver or platinum vessel ; the dry 
 saline mass is macerated with a solution of acetate of potassium (1 pt. of the salt to 
 4 pts. water) ; the uudissolved borofluoride of potassium is collected on a weighed filter 
 supported on a gutta-percha funnel, and washed, first with the solution of acetate of 
 potassium, which removes chloride, phosphate, and sulphate of potassium, likewise 
 sodium-salts though slowly, and afterwards with alcohol of 84 per cent. Tralles (spe- 
 cific gravity 0*8526), then dried at 100 C. and weighed. 100 parts of the borofluoride 
 correspond to 2778 boric anhydride, or 9*06 boron. 
 
 To ascertain whether the precipitate is pure, it is dissolved in boiling water, which 
 leaves behind any traces of magnesia that may be present, and the solution is treated 
 with ammonia, which precipitates silica if present : the precipitate may then be washed, 
 first with acetate of potassium, then with alcohol, and its weight ascertained. 
 
 The quantity of free boric acid in an aqueous or alcoholic solution, cannot be deter- 
 mined by evaporation to dryness, because a considerable quantity of the acid goes off 
 with the aqueous or alcoholic vapours : even the presence of excess of lead-oxide, 
 baryta, or basic phosphate of sodium, does not completely prevent this evaporation. 
 Ammonia prevents the volatilisation to a greater extent than either of these substances, 
 but it does not quite prevent loss. The only exact mode of determining boric acid by 
 evapoi-ation, is to supersaturate the liquid with a known weight of pure fused carbonate 
 of sodium (about 2 pts. of the c;irl><>n;ife to 1 pt. of acid supposed to be present) ; then 
 evaporate to dryni-ss, and ignite the residue in a covered crucible. The amount of 
 
BORON: DETECTION AND ESTIMATION. 631 
 
 carbonic anhydride in the residue is then to be determined by the method given under 
 ALKALIMETRY (p. 149), and deducting this, together with the known weight of soda 
 contained in the carbonate added, from the total weight of the residue, the remainder 
 is the quantity of boric anhydride present. 
 
 Boron in borates may be estimated indirectly in several ways. The best method is 
 to digest a weighed quantity of the pulverised compound in a capacious platinum 
 crucible, with hydrofluoric acid, then gradually add strong sulphuric acid, and heat 
 the mixture, gently at first, and afterwards to redness, till the excess of sulphuric acid 
 is expelled. The boron is then completely driven off as fluoride, and the bases remain 
 in the form of sulphates. If only one base is present, its quantity is easily calculated 
 from the weight of the residue. If two bases are present, e. g. potash and soda, the 
 amount of sulphuric acid in the residue must be ascertained ; the quantities of the two 
 bases may then be found by the method given under INDIRECT ANALYSIS (p. 224). If 
 more than two bases are present, they must be separated by the usual methods. The 
 weight of the bases deducted from that of the original substance, gives the amount of 
 boric anhydride. 
 
 Instead of driving off the boron as fluoride, it may be volatilised as borate of ethyl, 
 by treating the pulverised borate with strong sulphuric acid and alcohol. Or the 
 boric acid set free by the action of sulphuric acid, may be dissolved out by alcohol 
 and separated by filtration ; but this last method is applicable only when the resulting 
 sulphates are completely insoluble in alcohol. 
 
 Boric acid combined with potash or with soda, may be estimated volumetrically 
 by means of a standard solution of sulphuric acid. The solution is coloured with 
 tincture of litmus, and the sulphuric acid is cautiously added from a burette, till the 
 wine-red colour first produced by the liberation of the boric acid, changes to the bright 
 red which indicates the presence of free sulphuric acid : this takes place as soon as 
 the quantity of sulphuric acid (H 2 S0 4 ) amounts to 1 at. for 2 at. of potash or soda 
 (KHO or NaHO). Hence the amount of the base is found, and this deducted from 
 the total weight of the dry salt, gives the boric acid. 
 
 Separation of Boron from other Elements. When boric acid is in com- 
 bination with several bases, it is best to estimate the amount of these bases at once, 
 and determine the boric acid (or anhydride) by difference. From the metals of the 
 first group, copper, for example, boron is easily separated by sulphuretted hydrogen ; from 
 iron, and others of the second group, by sulphide of ammonium. From barium it is 
 separated by sulphuric acid ; from strontium and calcium, by sulphuric acid and alcohol ; 
 from magnesium, by ammonia and phosphate of sodium : the precipitate in this last 
 case generally contains a small quantity of boric acid. 
 
 The separation of boric acid from all these bases may likewise be effected by fusion 
 with alkaline carbonates ; in the case of magnesia, carbonate of potassium must be 
 used, because soda forms with magnesia an insoluble compound. 
 
 Sulphuric acid is easily separated from boric acid by precipitation with chloride of 
 barium ; hydrochloric, hydrobromic, and hydriodic acids, by adding nitrate of silver to 
 the solution acidulated with nitric acid; phosphoric acid, by ammonia and sulphate 
 of magnesium. 
 
 The estimation of boron in presence of fluorine is difficult. Metallic borofluorides 
 are analysed by heating them with sulphuric acid, whereby fluoride of boron and 
 hydrofluoric acid are driven off, and the metal remains as sulphate, from the weight 
 of which its quantity may be determined, and hence the amount of the boron and 
 fluorine together. If the compound contains water of crystallisation, it must be de- 
 termined by mixing the compound with 6 pts. of oxide of lead, covering the mixture 
 in a retort with a layer of oxide of lead, and exposing it to a heat short of redness. 
 The loss of weight gives the water. 
 
 In a mixture of a borate with a fluoride, it is impossible to determine either the 
 boron or the fluorine exactly. By dissolving the compound in excess of nitric acid, 
 and adding excess of carbonate of calcium, the fluorine is precipitated as fluoride of 
 calcium, but not completely, probably because a borofluoride is formed. 
 
 The estimation of boron in silicates is likewise difficult. If the silicate is decom- 
 posed by acids, like datolite or botryolite, it is finely pulverised, heated in a corked 
 flask with hydrochloric acid, at last nearly to boiling; the thick jelly is then diluted 
 with water and filtered ; the filtrate supersaturated with ammonia, which separates 
 alumina ; oxalic acid is added to precipitate lime ; and the filtrate, which now contains 
 nothing but boric acid in combination with ammonia, is evaporated in a platinum 
 capsule over the water-bath, with frequent addition of ammonia. The dry residue is 
 then gradually heated to redness in a covered platinum crucible, whereupon boric anhy- 
 dride remains mixed with a little silica. The boric anhydride is afterwards dissolved 
 out by water, and the residual silica weighed. The result is not quite exact, as a little 
 boric acid goes off oven in presence of excess of ammonia, but the loss is not considerable. 
 
 ss 4 
 
632 BORON: FLUORIDE. 
 
 In silicates not decomposible by acids, boron is estimated by heating the pulverised 
 mineral, first with hydrofluoric and then with sulphuric acid, whereby the boron and 
 silicium are expelled as fluorides. The bases then remain as sulphates, and are de- 
 termined by the ordinary methods. In another portion of the mineral, the silica is 
 determined by fusion with a mixture of the carbonates of potassium and sodium, 
 treatment of the residue with hydrochloric acid, evaporation to dryness, digestion of 
 the residue in acidulated water, filtration, and washing, whereupon the silica remains 
 on the filter in a state of purity, and may be ignited and weighed. The bases and the 
 silica having been thus determined, the boric anhydride is found by difference, the 
 result being of course affected by all the errors in the several determinations. 
 (H. Kose, Analyt, Chem. ii. 734.) 
 
 The estimation of boron in organic compounds, is generally effected by mixing the 
 compound with ammonia in a capacious platinum crucible, then evaporating and 
 igniting the residue. This method, according to Ebelmen, always involves a loss of at 
 least 2 per cent, of boron, and that loss may even amount to 4 per cent. A better 
 method might perhaps be to heat the compound with nitric acid in a sealed tube, ac- 
 cording to Carius's method (p. 247) : the boron would thereby be converted into 
 boric acid, and might then be estimated by any of the methods above given. 
 
 Atomic Weight of Boron. The earlier experiments of Gay-Lussac and Thenard, 
 Davy, and Berzelius, in which the atomic weight of boron was estimated by the amount 
 of oxygen absorbed in its combustion, did not lead to concordant results. Berzelius 
 afterwards determined its value from the amount of water in crystallised borax, which 
 in three experiments, he found to be 47' 1 per cent. Now supposing the formula of the 
 salt to be Na 2 0.2B 2 3 + 10IFO, and that the atomic weight of sodium is 23, this 
 result makes the atomic weight of boron equal to 11. Experiments by Deville,- re- 
 ported by Dumas (Ann. Ch. Phys. [3] Iv. 129), on the proportion of chlorine in 
 chloride of boron, gave, on the supposition that the formula of the chloride is BCF, 
 the two results B = 11-0 and B = 10 '6. Similar experiments with bromide of boron 
 BBr 3 , gave B = 11 0. This number appears therefore to have the greatest weight of 
 evidence in its favour. If the formula of chloride of boron were BC1 2 , the atomic 
 weight of boron would be 7 - 3. 
 
 BORON, FX.ITORZDX! OP. BF 3 . Discovered by Gay-Lussac and Thenard, in 
 1810. It is obtained : 1. By the action of boric anhydride on fluoride of calcium at 
 high temperatures : 
 
 6CaF + 7B 2 3 = 3(Ca 2 0.2B 2 3 ) + 2BF 3 . 
 
 An intimate mixture of 2 pts. fluorspar and 1 pt. vitreous boric anhydride, is intro- 
 duced into a gun-barrel closed at one end, and heated to whiteness in a furnace with 
 good draught, and the gas which escapes is received over mercury : borate of calcium 
 then remains behind. 2. By the action of hydrofluoric acid on boric acid or anhy- 
 dride, viz. by heating a mixture of 1 pt. boric anhydride (or 2 pts. fused borax), and 
 2 pts. fluor spar, with 12 pts. oil of vitriol, in a glass vessel : 
 
 6CaF + B 2 3 H- 3H 2 SO' = 3Ca 2 S0 4 + 3H-0 + 2BF 3 . 
 
 This method is easier than the former, but the gas which it yields is not quite pure, 
 as it contains a little fluoride of silicium, resulting from decomposition of the glass ; 
 moreover part of the fluoride of boron is converted by the water into boric and hydro- 
 fluoric acids. 
 
 Fluoride of boron is a colourless gas, of pungent suffocating odour, like that of 
 fluoride of silicium. Specific gravity = 2 - 37 (Davy); 2'31 (Dumas); and by cal- 
 culation : 
 
 11 + 3 2 m , 0-0693 = 2-29 
 
 It reddens litmus, fumes in damp air, and chars organic bodies like sulphuric acid. 
 It does not corrode glass. It is not decomposed by a red heat, or by the electric 
 spark. 
 
 Water absorbs about 700 times its volume of this gas, with great evolution of heat 
 and increase of bulk, forming an oily liquid of specific gravity 1'77, which when 
 boiled, gives off | of the dissolved gas, and leaves a residue consisting of B 2 3 .6HF, 
 or 2BF 3 .3H-O, which may be distilled without alteration. Water incompletely satu- 
 rated with fluoride of boron, deposits boric acid on cooling, or after standing for some 
 time, while fluoride of boron and hydrogen HF.BF 3 , remains in solution. 
 
 Strong sulphuric acid absorbs 50 times its volume of gaseous fluoride of boron, form- 
 ing a viscid liquid, which deposits boric acid when mixed with water. 
 
 Potassium, sodium, and the alkaU'iic ro/ril) -metals, heated in fluoride of boron, Tie- 
 come covered with a blackish crust, which bursts at a red heat, the metal then burning 
 
BORON: FLUORIDE. 633 
 
 with bright incandescence, and forming a metallic bore-fluoride, with separation of 
 boron. Iron does not act upon the gas, even at a bright-red heat. Quick lime absorbs 
 fluoride of boron readily when heated, forming a fusible mixture of fluoride and borate 
 of calcium. 
 
 Dry ammonia qas forms with an equal volume of fluoride of boron, a white, opaque, 
 solid compound, NH'JBF*, which volatilises undecomposed, and is converted by water 
 into borofl uoride and borate of ammonium. By the further action of ammonia on this 
 body, two liquid compounds, 2NH 3 .BF 3 , and 3NIF.BF 3 , are formed ; when exposed to 
 the air or heated, they give off ammonia and reproduce the solid compound. 
 
 According to Kuhlmann, fluoride of boron unites with nitric oxide, nitrous acid, 
 peroxide o'f nitrogen, and nitric acid. 
 
 Fluoboric Aoid. HB0 2 .3HF. This compound, discovered by Gray-Lussac and 
 Thenard, is obtained by saturating water with gaseous fluoride of boron, the vessel 
 being cooled with ice, and the gas-delivery-tube made to dip under mercury below the 
 water, as otherwise the rapid absorption would cause the liquid to run back into the 
 generating vessel. The saturated solution has a specific gravity of 177, and is nearly 
 pure fluoboric anhydride, B 2 3 .6HF, or hydrate of boric fluoride, 2BF 3 .3H 2 O (Gmelin's 
 tri-hydrofluate of boric acid, B&3HF, Handbook, ii. 363). On heating it, one-fifth 
 of the absorbed fluoride of boron goes off, and there remains a liquid of specific gravity 
 1-584, which is fluoboric acid, H 2 O.B <2 3 .6HF, or HB0 2 .3HF. 
 
 An easier mode of preparing this acid is to dissolve boric acid or anhydride in hy- 
 drofluoric acid contained in a platinum crucible externally cooled, avoiding an excess 
 of boric acid, then evaporate over the water-bath, gently boil the remaining liquid 
 in the covered crucible, till the vapours form a thick fume in the air, and leave the 
 liquid to cool over sulphuric acid. It may also be obtained by fusing an intimate 
 mixture of 10 pts. fluorspar and 8j crystallised borax, pulverising the fused mass, and 
 distilling it with 16| pts. strong sulphuric acid. The product thus obtained generally 
 contains a little silica derived from the distillation-vessel. 
 
 Fluoboric acid is an oily liquid, like oil of vitriol, fumes in the air, boils at a tem- 
 perature above 100 C., and distils without alteration. It is highly caustic, chars 
 organic bodies, and converts alcohol into ether. By dilution with water, it is decom- 
 posed, one-fourth of the boric acid being separated, and a solution of hydrofluoboric acid 
 remaining : 
 
 4(HB0 8 .3HF) - HBO 8 = 3HBF 4 + 6H 2 0. 
 
 Fluoboric acid forms salts, having the general formula MB0 2 .3MF. They are pro- 
 duced by the direct action of the acid on the bases, or by dissolving the corresponding 
 borates and fluorides in the proper proportions, and leaving the solution to evaporate. 
 But few of them have been examined. 
 
 The sodium-salt, NaB0 2 .3NaF + 1 aq, crystallises in small rectangular prisms, 
 having their terminal faces obliquely truncated ; they have an alkaline reaction, give 
 off their water at 40 C., and melt at a higher temperature. The fused salt, if quickly 
 cooled, solidifies to a clear glass ; but by slow cooling, it becomes turbid, from separa- 
 tion of fluoride of sodium, which remains undissolved on treating the mass with cold 
 water, whereas boiling water dissolves the whole, reproducing the original salt. 
 
 Another fluobbrate of sodium, NaHB 2 4 .6NaF+ lOaq, is produced by slowly eva- 
 porating a solution of 1 at. borax and 6 at. fluoride of sodium. It crystallises in small 
 rectangular four-sided prisms, which become turbid at 40 C. from loss of water, and 
 behave like the preceding when melted and slowly cooled. (Handw. d. Chem. 2 te Aufl. 
 ii. [2] 279.) 
 
 Hydrofluoboric Acid. HBF 4 =BF 3 .HF. Obtained bypassing gaseous fluoride 
 of boron into water, till the liquid is strongly acid, and exposing it to a low tempe- 
 rature. Boric acid then separates, and hydrofluoboric acid remains in solution : 
 4BF 3 + 2H 2 = 3BHF 4 + HBO 2 . 
 
 A similar solution is obtained by dissolving crystallised boric acid to saturation in 
 moderately strong hydrofluoric acid artificially cooled. 
 
 Hydrofluoboric acid is known only in the state of dilute solution. It is decomposed 
 by concentration, yielding hydrofluoric and fluoboric acids : 
 
 BHF 4 + 2H 2 = HF + HB0 2 .3HF. 
 
 In the dilute state, it does not attack glass ; but if it be concentrated in a glass vessel, 
 the glass becomes corroded, from separation of hydrofluoric acid ; if, however, boric 
 acid be added during the concentration, so as to form fluoboric acid, no corrosion of 
 the glass takes place. 
 
 Boroflnoridcs. These salts, whose composition is expressed by the general 
 formula, MBF 1 or MF.BF :I , are formed by the action of gaseous fluoride of boron or 
 
634 BORON: FLUORIDE. 
 
 aqueous fluoboric acid on metallic fluorides ; by the action of metallic oxides on hydro- 
 fluoboric acid ; or by dissolving a metallic fluoride, together with boric acid, in aqueous 
 hydrofluoric acid; sometimes also by merely bringing a fluoride in contact with 
 boric acid, the liquid then becoming alkaline if previously neutral, or even if acid. 
 
 Most borofluorides are soluble in water, and are obtained in the crystalline state 
 by evaporating their aqueous solutions. At a red heat, they are resolved into fluoride 
 of boron and metallic fluoride. Distilled with sulphuric acid, they give off gaseous 
 fluoride of boron and aqueous hydrofluoboric aeid. They are for the most part not 
 decomposed by heating with alkalis or alkaline carbonates. 
 
 Borofluoride of Aluminium, crystallises by slow evaporation from a solution of hydrate 
 of aluminium in excess of hydrofluoboric acid ; the crystals dissolve in water only 
 when free acid is present. On mixing a solution of chloride of aluminium with boro- 
 fluoride of sodium, a basic borofluoride of aluminium is precipitated, which, at a red 
 heat, is resolved into fluoboric acid and borate of aluminium. 
 
 Borofluoride of Ammonium, NH 4 F.BF 3 , is obtained by subliming a mixture of the 
 potassium-salt with sal-ammoniac, or more easily by dissolving boric acid in aqueous 
 fluoride of ammonium, ammonia being then evolved : 
 
 4NH 4 F + H 3 BO S = NH 4 F.BF 3 + 3H 2 + 3NH 3 . 
 
 It crystallises by evaporation in six-sided prisms with dihedral summits ; dissolves 
 readily in water, somewhat less in alcohol ; reddens litmus ; does not attack glass ; 
 dissolves in aqueous ammonia, and crystallises out unaltered ; sublimes when heated. 
 
 Borofluoride of Barium, 2BaBF 4 .H 2 0. Prepared by saturating hydrofluoboric acid 
 with carbonate of barium, avoiding an excess, otherwise fluoride of barium and boric 
 acid are produced. Crystallises from a warm solution in long needles ; by slow evapo- 
 ration in a warm atmosphere, in smooth rectangular prisms, often arranged in steps 
 like common salt. Has an acid reaction ; tastes like barium-salts in general ; dis- 
 solves readily in water ; deliquesces in moist air. Alcohol decomposes it, dissolving an 
 acid salt, and separating a white powder. The crystals effloresce at 40 C. and decom- 
 pose at a higher temperature. 
 
 Borofluoride of Calcium. A solution of carbonate of calcium in hydrofluoric acid, 
 deposits on evaporation, a gelatinous mass, which dries up to a white powder, reddens 
 litmus, and is decomposed by water, with separation of a basic salt. 
 
 Borofluoride of Copper, CuBF 4 . Light blue needles obtained by decomposing the 
 barium-salt with sulphate of copper, and evaporating the filtrate. 
 
 Borofluoride of Lead, PbBF 4 . Prepared like the barium-salt, and crystallises with 
 difficulty by spontaneous evaporation, in four-sided prisms ; from the solution evapo- 
 rated to a syrup, in long prisms. Has a sweetish taste, with sour astringent aftertaste. 
 Partially dissolved by water and by alcohol. Heated with oxide of lead, it is said to 
 yield an easily fusible oxyborofluoride, whose aqueous solution is rendered turbid by 
 the carbonic acid in the air. 
 
 Borofluoride of Lithium, LiBF 4 Prepared like the copper-salt, and separates by 
 evaporation at 40 C. in large prismatic crystals, which have a rather bitter and acid 
 taste, and deliquesce in the air, sparingly soluble rhombohedral crystals then sepa- 
 rating, which have not been further examined. 
 
 Borofluoride of Magnesium. Easily soluble; crystallises in large prisms; tastes 
 bitter. 
 
 Borofluoride of Potassium KBF 4 . Formed like the ammonium-salt, by adding 
 boric acid to aqueous fluoride of potassium. It may be prepared by dissolving 2 at. 
 (124 pts.), of crystallised boric acid, and 1 at. (138 pts.) carbonate of potassium in excess 
 of hydrofluoric acid, or by adding a soluble potassium-salt to hydrofluoric acid ; it 
 then separates as a transparent gelatinous precipitate, which appears iridescent by 
 reflected light while suspended in the liquid, and dries up to a white powder. It 
 dissolves in 70 pts. of cold, and in a smaller quantity of hot water, and crystallises 
 from the solution in anhydrous, shining, six-sided prisms. It has a bitterish taste, 
 and does not redden litmus. Alkalis do not d'ssolve it more readily than pure 
 water. Ammonia does not alter it, unless the solution contains silica, in which case a 
 precipitate is formed. It dissolves in boiling alcohol. When heated, it first melts, 
 then gives off fluoride of boron, and if not quite dry, likewise fluoboric acid ; and after 
 prolonged exposure to a strong heat, leaves fluoride of potassium. Strong sulphuric 
 acid decomposes it but slowly, even with the aid of heat. 
 
 Borofluoride of Sodium, NaBF 4 , forms short four-sided rectangular prisms, very 
 soluble in water, less in alcohol ; has a rather bitter and acid taste, and reddens 
 litmus. The crystals are anhydrous, melt below a red heat, but require strong and 
 prolonged ignition to decompose them completely into fluoride of boron and fluoride 
 of sodium. 
 
 Borofluoride of YiUrum dissolves only in water containing free acid. It is 
 
BORON: IODIDE OXIDE. 635 
 
 obtained in crystals by dissolving yttria in excess of hydrofluoboric acid, and 
 evaporating. * 
 
 Borofluoride of Zinc, ZnBF 4 . Zinc dissolves in hydrofluoboric acid with evolution 
 of hydrogen. The solution evaporated to a syrup, solidifies at low temperatures to a 
 deliquescent mass. 
 
 BORON, IODIDE OP. Not yet obtained in the pure state. Iodine and boron 
 strongly heated together, form a product which appears to be an oxyiodide ( Wo'hler 
 and Deville). Boron does not decompose iodide of silver, even at temperatures 
 above the melting point of the metal. 
 
 According to Inglis, a mixture of boric anhydride and charcoal heated in iodine - 
 vapour, yields a yellow sublimate, which has not been examined. 
 
 BORON 1 , NITRIDE OP. BN. This compound was discovered by Balm ain 
 (Phil. Mag. [3] xxi. 170 : xxii. 467 ; xxiii. 71 ; xxiv. 191), who at first regarded it as 
 capable of uniting with metals and forming compounds analogous to the cyanides ; 
 but afterwards found that all these supposed metallic compounds were one and the 
 same substance, viz. nitride of boron without any appreciable amount of metal. 
 This conclusion has been confirmed by Marignac (Ann. Ch. Pharm. Ixxix. 247). 
 Balmain obtained this substance by heating boric anhydride with cyanide of potassium 
 or cyanide of zinc, or with cyanide of mercury and sulphur. It has since been more 
 completely investigated by Wohler (Ann. Ch. Pharm. Ixxiv. 70), who prepares it by 
 heating to bright redness in a porcelain or platinum crucible a mixture of 2 pts. 
 dried sal-ammoniac and 1 pt. pure anhydrous borax : 
 
 Na*0.2B 2 O s + 2NH'C1 = 2BN + 2NaCl + B 2 3 + 4K-'0. 
 
 The product is a white porous mass, which is pulverised and washed with water to 
 free it from chloride of sodium and boric anhydride, the final washings being made 
 with boiling water acidulated with hydrochloric acid. The boric anhydride is, how- 
 ever, so completely incorporated with the nitride of boron, that it cannot be wholly 
 removed by washing. A purer product might perhaps be obtained by using neutral 
 Iterate of sodium instead of borax, in which case, no excess of boric anhydride would 
 be present : 
 
 Na 2 O.B 2 3 + 2NH 4 C1 = 2BN + 2NaCl + 4H 2 0. 
 
 Wohler formerly prepared nitride of boron by igniting anhydrous borax with ferro- 
 cyanide of potassium. It is likewise produced when amorphous boron is heated to 
 whiteness in a stream of pure nitrogen ; more easily, but with simultaneous formation 
 of boric anhydride, when boron is ignited in a current of air, or of nitrous or nitric 
 oxide gas ; also, with incandescence and evolution of hydrogen, when boron is heated 
 in gaseous ammonia. (Wohler and Devi lie, Ann. Ch. Pharm. cv. 69.) 
 
 Nitride of boron is a white amorphous powder, tasteless, inodorous, soft to the 
 touch, insoluble in water, infusible, and non-volatile. If very pure, it exhibits when 
 heated at the edge of a flame, a brilliant greenish-white phosphorescence, undergoing 
 at the same time a slow oxidation. Heated in an alcohol-flame fed with oxygen gas, 
 it burns rapidly, with faint greenish-white flame, giving off fumes of boric anhydride. 
 It easily reduces the oxides of copper and lead, giving off nitrous fumes. Heated in a 
 current of aqueous vapour, it yields ammonia and boric anhydride : 
 
 2BN + 3H 2 = B 2 3 + 2NH 3 . 
 
 Alkalis, and the greater number of acids, even in the state of concentrated solution, 
 have no action on nitride of boron ; strong sulphuric acid, however, with the aid of heat, 
 ultimately converts it into ammonia and boric acid. Fuming hydrofluoric acid con- 
 verts it into borofluoride of ammonium. Nitride of boron undergoes no alteration 
 when heated in a current of chlorine. When fused with hydrate of potassium, it 
 gives off a large quantity of ammonia. With anhydrous carbonate of potassium, it 
 yields borate and cyanate of potassium : 
 
 BN + 2(K 2 CO S ) = KBO 2 + KCNO. 
 
 It does not decompose carbonic anhydride, even at the highest temperatures. 
 
 BORON, OXIDE OP. Boric Oxide or Anhydride. Anhydrous boric acid, B 2 3 . 
 This the only known oxide of boron. It is formed when boron burns in oxygen gas, 
 in the air, or in nitric oxide gas (p. 626) ; but it is more. easily obtained by exposing 
 boric acid, which is its hydrate, to a strong heat. Water then goes off, and the an- 
 hydride melts to a viscid mass, which, on cooling, solidifies to a colourless brittle glass 
 (vitr\fied boric orboracic acid) of specific gravity 1'83. It cracks .spontaneously in 
 i-ooling, and the formation of each crack is attended with a flash of light (Dumas). 
 It is perfect Jy fixed in the fire when alone, but in presence of water, und still more of 
 
636 BORON: OXIDE. 
 
 alcohol, it volatilises to a considerable amount. It is perfectly inodorous ; has a 
 slightly bitter but^not sour taste ; dissolves readily in water, forming boric acid, also in 
 alcohol. The alcoholic solution burns with a green flame; so likewise does a mixture 
 of boric anhydride and sulphur. 
 
 Potassium heated with boric anhydride decomposes it with visible combustion ; 
 sodium decomposes it quietly. It is not decomposed by phosphorus-vapour at a red heat, 
 or by charcoal even at a white heat (G-melin). It unites with metallic oxides when 
 fused with them, forming borates. From its fixity in the fire, it is capable of decom- 
 posing at high temperatures, not only carbonates, but likewise nitrates, sulphates, and 
 indeed the salts of all acids which are more volatile than itself. 
 
 Boric Acid. 
 
 Oxide of Boron and Hydrogen. Boracic Acid. Sel sedativum Hombergii. Sel 
 narcoticum mtrioli. H 3 B0 3 or 3H 2 O.B 2 O S . This acid is formed by the oxidation of 
 boron in presence of water, e. g. by the action of nitric acid or aqua-regia on boron ; 
 also by dissolving the anhydride in water. It occurs native in the free state in many 
 volcanic districts, especially in Tuscany, where it issues from the earth together with 
 vapour of water, and is found, either as an eifloresence in the neighbourhood of hot 
 springs, or dissolved in the water of small lakes or lagoons (Laguni), formed by 
 the vapours themselves. It is also found in small quantity in several mineral waters, 
 viz. in the boiling spring of Wiesbaden ; in the iodine- water of Krankenheil near 
 Folz, and of the Kaiser spring in Aachen ; in the mother- liquor of the salt-spring at 
 Bex (Baup), and in several hepatic waters. A few borates are also found in nature 
 (p. 626), especially borax, the acid borate of sodium, which exists in the water of 
 certain lakes in Central Asia. 
 
 Preparation. On the small scale, boric acid is prepared from borax. 3 pts. of 
 crystallised borax are dissolved in 12 pts. of boiling water, and to the filtered solution 
 is added 1 pt. of strong sulphuric acid, or so much hydrochloric acid that the liquid 
 strongly reddens litmus. The greater part of the boric acid then separates on cooling 
 in crystalline scales, and a larger quantity may be obtained by evaporating the mother- 
 liquor. The crystals retain a certain portion of sulphuric or hydrochloric acid ; from 
 the latter they are easily freed by gentle heating and recrystallisation. To obtain 
 them free from sulphuric acid, they must be fused in a platinum crucible, and then 
 recrystallised. 
 
 Formerly all the boric acid of commerce was obtained from borax. It was first 
 separated in 1702 by Homberg, who prepared it by heating borax with calcined ferrous 
 sulphate in closed vessels, whereby sodio-ferric sulphate was formed, and boric acid 
 was carried over with the watery vapour which escaped. Boric acid may also be prepared 
 by the decomposition of other native borates, e.g. borate of magnesium (boracite), 
 and borate of calcium and sodium (boronatrocatcite). 
 
 Preparation on the large scale (Pay en, Precis de Chimie industrielle, 4 me d. 
 1859, i. 423). All the boric acid of commerce is now obtained from the volcanic 
 district of Tuscany, where it is discharged from the interior of the earth by numerous 
 jets of vapour called suffioni, often rising in thick columns to a considerable height. 
 The entire surface of the district, consisting of chalk and marl, is subject to constant 
 shocks caused by subterranean agencies ; and columns of boiling water are frequently 
 projected into the air, which is also strongly impregnated with sulphuretted hydro- 
 gen. These vapours contain, besides aqueous vapour, carbonic acid, sulphydric 
 acid, nitrogen, hydrogen, a gaseous hydrocarbon, and sometimes oxygen, together 
 with a small quantity of boric acid and much solid matter carried up mechanically. 
 Ch. Deville and F. Leblanc found, in the vapour of one of the suffioni, about 91 per 
 cent. CO 2 , 4 per cent. IPS, and 5 per cent, nitrogen and combustible gases. 
 
 The vapours which issue from the clefts do not contain any appreciable quantity of 
 boric acid, but where pools are formed rotind the suffioni, either artificially or by 
 natural condensation of the vapours, the water soon becomes charged with boric acid. 
 Probably the greater part of the acid is first deposited on the sides of the clefts 
 before it reaches the surface, and when water penetrates into them, the acid is dis- 
 solved and thrown up in the state of solution. 
 
 To obtain the boric acid, the suffioni are surrounded with basins of coarse masonry, 
 glazed on the inside, and large enough to enclose two or three suffioni. A series of these 
 basins are constructed on the hill-side, and into the uppermost AB (fig. 106), the water 
 of a spring is turned, and after remaining there 24 hours, during which time it is kept 
 in a state of constant agitation by the subterranean vapour, it is made to pass through 
 the tube a, into a second basin C D, where it likewise remains 24 hours, and takes up 
 a second quantity of boric acid ; thence it passes successively by the pipes b, c, into 
 the third and fourth basins, the liquid discharged from a lower basin being con- 
 tinually supplied from the one above it. When the liquid has thus traversed six 
 
BORIC ACID. 
 
 637 
 
 or eight of these lagoons, it is found to have taken up about 0'5 per cent, of boric 
 acid, and to have a specific gravity of 1*007 to I'OIO. 
 
 Fig. 106. 
 
 From the last lagoon G, H (figs. 107, 108), the solution passes into a large vessel I, 
 called a vasco, where it deposits a quantity of mud, and afterwards into two smaller 
 reservoirs J, K, for further clarification. From K it passes into a series of leaden 
 pans, shown in section in fig. 106 and in plan in fig. 107, placed one above the other 
 in the manner of terraces on a wooden scaffold. Formerly these pans were heated by wood 
 fires ; but this was found too costly, the district being nearly bare of wood ; the evapo- 
 ration is now performed by means of the subterranean heat, one or more of the jets 
 
 Fig. 107. 
 
 of steam enclosed in pipes being conducted between the foundation and the bottom of 
 the pans. The steam enters beneath the bottom pans, and is carried regularly upwards, 
 so that the lowest pans, which contain the most concentrated liquid, become most 
 heated. This mode of utilising the subterranean heat was introduced in 1817, by 
 Count Larderel, at that time the proprietor of all the lagoons, and had the effect of 
 converting an unprofitable branch of industry into one which is now the source of 
 immense wealth. 
 
 Another form of apparatus for the evaporation is shown in fig. 109. The liquid, 
 after leaving the vascos A, B, passes into a shallow boiler C, from which it is made to 
 
638 
 
 BORON: OXIDE. 
 
 run slowly over an inclined sheet of lead, D, E, about 150 feet long, and having corruga- 
 tions on its surface, which form a series of channels. The liquid, in running over this 
 
 Fig. 109. 
 
 surface, gradually evaporates, and the solution ultimately reaches the basin F, at a 
 degree of concentration fit for crystallisation. Heat is supplied by the vapour of one 
 of the suffioni introduced under the basin F, and carried up under the sheet of lead to C. 
 This method of evaporation is easier than the preceding, and does not introduce so 
 much lead into the solution. 
 
 The solution of boric acid concentrated by either of these methods, is next mixed 
 with the mother-liquor of a preceding operation, and poured through the funnels R, 
 into the round crystallising tubs S, S, (figs. 107 108, 110) which are made of wood lined 
 
 Fig. 110. 
 
 Fig. 111. 
 
 with lead. The crystals are taken out after a while, and placed to drain in baskets, J, 
 on the top of the tubs, the mother-liquor running into receivers placed under the floor. 
 
 Lastly, the crystals, while still moist, are spread out on the floor C C, of the drying 
 chamber D (jig. 111). _ This chamber has a double floor, and is heated by steam enter- 
 ing at A, and circulating between the two floors. 
 
 The product thus obtained is far from pure, not containing more than about 76 per 
 cent, of boric acid. The composition of the crude acid, according to the analyses of 
 Wittstein and Payen, is as follows : 
 
 Crystallised boric acid 
 Ferric sulphate . 
 Sulphate of aluminium 
 Sulphate of calcium 
 Sulphate of magnesium 
 Sulphate of ammonium 
 Sulphate of sodium 
 Sulphate of potassium 
 Sulphate of manganese 
 Chloride of ammonium 
 Silica .... 
 Sulphuric acid . 
 Water 
 
 Wittstein. 
 76-5 
 
 0-4 
 
 0-3 
 
 1-0 
 ' 2-6) 
 
 8-5 \ 
 
 0-9 
 
 0-4 
 trace 
 
 0-2 
 
 1-2 
 
 1-3 
 
 6-6 
 
 Payen. 
 74 to 84 
 
 2-4 to 1-2 * 
 14-0 to 8 
 
 2-6 to 1-0 
 
 7-0 to 5-8 f 
 
 Schmidt found, in crude boric acid from Tuscany, 80 per cent, boric acid and 20 per 
 cent, impurities, chiefly the sulphates of ammonium and magnesium. Bichardson and 
 Browell found in some samples, not more than 36 to 42 per cent, of the pure acid 
 [? crystallised or anhydrous]. The experience of the French manufacturers of borax, 
 seems to show that the impurities in boric acid from Tuscany become greater year by 
 year, which may perhaps be due to the increasing disintegration of the earthy strata 
 by the aqueous and acid vapours. 
 
 Of the origin of the vapours by which the boric acid is brought to the surface, nothing 
 certain is known. Dumas has suggested that they may proceed from a deep-seated 
 bed of sulphide of boron, with which the water of lakes, or of the sea, comes in contact, 
 thereby producing boric and sulphydric acids. Part of the boric acid may thus be 
 supposed to act upon the carbonates of calcium and magnesium in the soil, converting 
 
 Including sand, clay, &c. 
 
 t Including organic matter. 
 
BORATES. 639 
 
 them into borates, and setting free carbonic anhydride. The sulphuretted hydrogen 
 being oxidised by the air, yields free sulphur, which is deposited on the edges of 
 the suffioni. The ammonia and organic matter are derived from the water, and the 
 saline impurities from the water and the earthy strata, through which the vapours 
 make their way. Bolley supposes that the boric acid and ammonia may result from 
 the action of solution of sal-ammoniac at a boiling-heat, on borates contained in the 
 earth ; and according to "Warington, the formation of these products may be ascribed to 
 the action of water on nitride of boron. There is, however, nothing positive to indi- 
 cate the nature of the particular compound or compounds of boron, to which the elimi- 
 nation of the boric acid is really due. 
 
 Properties. Boric acid crystallises from water in white, translucent, nacreous, six- 
 sided laminae, somewhat unctuous to the touch ; it is inodorous, and has a faint, 
 scarcely acid, rather bitterish, cooling taste. Specific gravity = 1*48. It dissolves in 
 2-57 parts of water at 18 C. ; in 14'9 parts at 25, in 107 parts at 50, in 47 parts 
 at 75, and in 2'97 parts at 100. (Brandes and Eirnhaber.) It is still .mor^ 
 soluble in alcohol and in volatile oils. 
 
 Boric acid dissolves in warm concentrated sulphuric, nitric, or hydrochloric acid, but 
 separates for the most part on cooling, or on addition of water. Its solubility in water 
 is increased by addition of tartaric acid, tartrate of potassium, Rochelle salt, racemic 
 acid, or alkaline racemates. 
 
 The crystallised acid heated to 80 100 C., gives off 21-8 per cent, water, that is to 
 say, half the quantity which it contains, leaving H 6 B 4 9 or 3H 2 0.2B 2 3 (according to 
 Schaffgotsch, it gives off nearly all its water at 100 C.) ; by prolonged heating to 
 160 it is deprived of 2 at. water more, leaving H 2 B 4 7 = H 2 0.2B 2 3 , and at a 
 stronger heat, the remaining water goes off, leaving the anhydride B 2 3 , as a fused 
 viscid mass, which solidifies to a fissured glass on cooling (p. 635). 
 
 Reactions. A cold saturated aqueous solution of boric acid colours litmus -tincture 
 wine-red (the tint of port wine), like carbonic acid, but a hot saturated solution 
 colours it bright red. Turmeric paper moistened with the alcoholic solution of boric 
 acid acquires a reddish-brown colour, quite different from that produced by alkalis, 
 and becoming distinct only after drying : it is intensified by acids, especially by 
 hydrochloric, sulphuric, nitric, and tartaric acids, and turned black by alkalis. 
 
 The alcoholic solution of boric acid burns with a beautiful green-edged flame, a 
 reaction which is quite characteristic of boron, provided copper and certain chlorine- 
 compounds are absent. This green colour is not produced, however, when the acid is " 
 in combination with an alkali or other base ; and its production is partly prevented 
 by the presence of chloride of sodium or calcium, and even by small quantities of tar- 
 trate of potassium or Rochelle salt (doubtless because these salts are partly decomposed 
 by the boric acid, and neutralise it), also by free tartaric acid or phosphoric acid. In 
 either of these cases, the green colour appears on addition of sulphuric acid, or of a 
 considerable quantity of hydrochloric acid (H. Rose, Pogg. Ann. cii. 545). It must 
 be observed, however, that a green flame, though of a more bluish tint, is produced 
 when hydrochloric acid itself is dropped into burning alcohol. (See p. 630.) 
 
 For the reactions with metallic salts see p. 640. 
 
 Borates. (Berzelius, Traite, vol. i iv. Gm. vol. i vi. Handw. d. Chem. 
 2 te Aufl. ii. [2] 303. H' Rose, Pogg. Ann. ix. 76 ; Ixxxvi. 581 ; Ixxxvii. 1, 470 and 
 587; Ixxxviii. 299, 482; xci. 452. Wohler, ibid, xxviii. 525. Rammelsberg, 
 ibid. Ixix. 445. Eb elm en, Ann Ch. Phys. [3] xxxiii. 34. H erapath. Ann. Ch. 
 Pharm. Ixxii. 254. Bolley, ibid.^ Ixviii. 122. Laurent, Ann. Ch. Phys. [2] Ixvii. 
 215. Tissier, Compt. rend, xxxix. 192; xlv. 411. Bloxam, Chem. Soc. Qu. J. 
 xii. 177 ; xiv. 143.) Boric acid forms salts in which the proportion of anhydrous base 
 (M 2 O) to anhydrous acid (B 2 O 3 ), or of metal to boron, ranges between the limits 9 : 1 and 
 1 : 6. Those which contain equal proportions of base and acid are usually regarded 
 as neutral or normal borates, the rest as basic or acid. The following proportions 
 have been observed : 
 
 Basic. Neutral. Acid. 
 
 9M 2 O.B 2 S M 2 O.B 2 9 2M 2 0.3B 2 3 
 
 6M 2 O.B 2 S M 2 0.2B 2 S 
 
 9M 2 O.2B 2 3 M 2 0.3B 2 S 
 
 3M'O.B 2 3 M 2 0.4B 2 3 
 
 5M 2 0.2B 2 S M 2 0.5B 2 3 
 
 2M-O.B 2 3 M 2 0.6B 2 3 
 
 3M 2 0.2B 2 3 
 
 Most of the so-called acid borates, however, contain several atoms of water; and if 
 the whole or part of this water be regarded as basic, we shall find that nearly all 
 borates may be arranged in two classes, orthoborates and metaborates (so called 
 
640 BORON: OXIDE. 
 
 from their analogy with the ortho- and meta-phosphates and silicates), the composition 
 of which may be represented by the following general formulae, the symbol M denoting 
 either a single metal, or two, or three metals, including hydrogen : 
 
 Orthoborates 3M 2 O.B 2 8 , or M 3 B0 3 = ^,!|o 3 
 Metaborates w(M 2 O.B 2 3 ), or M'B'O 2 " = ",, n 0*> 
 
 The latter formula, which, when n = 1, becomes that of the so-called neutral 
 borates, MBO 2 , includes the greater number of the salts of boric acid. Nevertheless 
 it appears probable that boric acid is essentially tribasic, and that the borates con- 
 taining 3 at. metal to 1 at. boron are its normal salts (hence called orthoborates) : 
 for crystallised boric acid contains H 3 B0 3 ; and there are boric ethers containing 3 at 
 alcohol-radicle to 1 at. boron, whereas none are known of the form KBO 2 . Moreover 
 it appears from the experiments of Bloxam, that boric acid, when ignited with metallic 
 hydrates, mostly drives out 3 at. of water, forming a trimetallic borate, except in the case 
 of hydrate of potassium, in which the water is retained with peculiar force ; and when 
 heated to bright redness with carbonates, it expels a quantity of carbonic anhydride 
 approaching more nearly to 3 atoms as the base is weaker, that limit being actually 
 reached in the case of strontia. (See BORATES OF BARIUM, LITHIUM, POTASSIUM and 
 SODIUM.) There appear also to be a few borates intermediate in composition between 
 ortho- and metaborates, viz. M 4 B 2 5 = M 3 B0 3 .MB0 2 . 
 
 Borates containing more than 3 at. metal to 1 at. boron may be regarded as com- 
 pounds of orthoborates with metallic oxides or hydrates (see BORATES OF ALUMINUM) ; 
 and those anhydrous borates which contain more than 1 at. boron to 1 at. metal may 
 be regarded as metaborates combined with boric anhydride ; e. g. anhydrous borax, 
 Na 2 0.2B 2 3 = 2NaB0 2 .B ? 3 . 
 
 Borates are formed by the action of boric acid on metallic oxides or their salts, 
 either in the wet or in the dry way. At high temperatures, boric acid or anhydride 
 decomposes carbonates, sulphates, chlorides, and indeed the salts of all volatile acids. 
 Acid borates, borax for example, take up additional quantities of base when ignited 
 with metallic oxides, and likewise decompose the salts of volatile acids. In the wet 
 way, on the contrary, boric acid acts as a very weak acid, being separated from its 
 combinations completely by most acids, and partially, under certain circumstances, even by 
 carbonic acid, sulphydric acid, and water. In concentrated solution, however, it decom- 
 poses carbonates, especially at the boiling heat ; also soluble sulphides and precipitated 
 sulphide of manganese. It has but little power of neutralising the alkaline reaction 
 of the stronger bases, so that even the solutions of many of the polyacid borates 
 exhibit a strong alkaline reaction to litmus, which is not neutralised till the base is 
 combined with 5 or 6 atoms of boric acid, and even then the liquid does not exhibit 
 an acid reaction. 
 
 The borates of the alkali-metals dissolve readily in water, but are precipitated by 
 alcohol. All other borates dissolve but sparingly soluble in water ; but none are perfectly 
 insoluble. The sparingly soluble borates may be obtained by precipitation. Many of 
 these precipitates are soluble in excess of the soluble metallic salt from which they have 
 been formed, but not in excess of alkaline borate ; e. g. the precipitate formed by borax 
 dissolves in solution of chloride of barium, but not of borax : they are often likewise 
 soluble in chloride of ammonium and in free boric acid. The sparingly soluble borates 
 are easily decomposed by water, especially when boiled with it, the boric acid being 
 sometimes almost completely removed. Hence it is very difficult to obtain these salts 
 in the pure state. H. Rose, in his elaborate investigation of the borates, purified the 
 precipitates as completely as possible by repeated pressure between paper without 
 washing, and afterwards estimated the quantity of foreign salts still attached to the 
 precipitate. The soluble borates are likewise decomposed by water. If a strong 
 solution of borax be mixed with slightly reddened tincture of litmus, the liquid retains 
 its faint red colour, but on dilution with water becomes distinctly blue, behaving 
 indeed like a dilute solution of free alkali mixed with boric acid. Neutral borates of 
 alkali-metal exhibit a similar reaction. 
 
 When a solution of an alkaline borate coloured with tincture of litmus is gradually 
 mixed with sulphuric acid, the liquid exhibits a wine-red colour till all the alkali is 
 saturated with sulphuric acid; after that, a single drop of sulphuric acid produces the 
 bright red colour. 
 
 Solutions of alkaline borates absorb carbonic and sulphydric acid gases ; expel am- 
 monia from its salts when boiled with them, like dilute alkalis ; their dilute solutions 
 also react like alkalis with mercury and silver-salts, and with many organic substances. 
 (See BORAX, p. 6-18.) 
 
 The soluble borates, both neutral and acid, give white precipitates with solutions of 
 
BORATES. 641 
 
 chloride of barium, chloride of calcium, alum, sulphate of zinc and nitrate of lead ; red- 
 dish with sulphate of cobalt ; greenish with sulphate of nickel ; yellowish with/erne sul- 
 phate in the cold, brown on boiling. These precipitates dissolve easily in sal-ammoniac ; 
 and if they have been produced by an acid borate of alkali-metal, borax for example, 
 they dissolve pretty readily in an excess of the salt from which they have been obtained ; 
 The precipitates formed by neutral borates of alkali-metal in the same solutions ex- 
 hibit similar characters, excepting that they are less soluble in excess of the earth- 
 metal or heavy metal salt. 
 
 Solution of borax or of monoborate of sodium, does not precipitate sulphate of 
 magnesium in the cold ; but on heating, a precipitate forms which disappears again on 
 cooling ; completely ; if formed by the acid borate ; nearly, if by the neutral borate. 
 Both neutral and acid borates of alkali-metal form with manganous salts, a precipitate 
 insoluble in excess of the latter, easily soluble in sal-ammoniac. 
 
 Dilute solutions of neutral borates of alkali-metal form with nitrate of silver, a 
 brown precipitate of nearly pure oxide of silver, insoluble in excess of water, easily 
 soluble in ammonia or nitric acid. A concentrated solution of neutral borate forms 
 with silver-salts, a brown precipitate which dissolves in a large quantity of water, 
 leaving only a slight residue of oxide of silver. Concentrated solutions of acid 
 borates of alkali-metal form with nitrate of silver a white precipitate of borate of 
 silver, completely soluble in a large quantity of water. Borate of ammonium forms a 
 white precipitate in concentrated silver-solutions, none in dilute solutions. 
 
 Soluble borates, whether neutral or acid, give with mercuric chloride, a brown 
 precipitate of oxychloride, insoluble in excess of the mercury-salt. Concentrated 
 solutions give with neutral mercurous nitrate, a yellow-brown precipitate, soluble in 
 much water: dilute solutions, a blackish -grey precipitate which remains long sus- 
 pended. Basic mercurous nitrate forms with a strong solution of borax, a dingy, 
 yellow-brown precipitate which dissolves in a large quantity of water, leaving black 
 mercurous oxide. 
 
 If the solution of a calcium or magnesium salt be mixed with excess of boric acid, 
 and to the boiling solution borax be added in quantity just sufficient to neutralise the 
 acid of the calcium or magnesium salt, no precipitate is formed ; similarly with salts 
 of manganous, ferrous, cobalt, nickel, cadmium and zinc salts; but solutions of 
 aluminium, chromicum, ferricum, stannicum, lead and copper, yield precipitates when 
 thus treated. (Tissier.) 
 
 For the reactions of borates with fluorspar and acid sulphate of potassium before the 
 blowpipe (see p. 630). 
 
 BORAXES OF ALUMINIUM. A solution of alum mixed with alkaline borates yields 
 precipitates which, according to H. Rose, are double salts of borate of aluminium and 
 borate of the alkali-metal mixed with sulphate of potassium; water abstracts the 
 greater part of the latter and of the alkaline borate, leaving a basic borate of aluminium. 
 In this manner, the precipitate produced by monosodic borate yields sexbasic borate 
 of aluminium, 2(A1 4 3 )'".B 2 3 + 3 aq. = 6aZ 2 O.B 2 3 + 3aq., which may also be regarded 
 as an orthoborate combined with 3 at. hydrate of aluminium = <Zi? 3 B0 3 .3aEIO. By 
 adding acid borate of sodium (borax) to solution of alum, a precipitate is formed con- 
 taining 3(A1 4 O 3 )'".2B 2 3 + 7 aq. = 9^ ; 0.2B 2 3 + 7aq. or 2a^B0 3 .3a/HO + 2aq. 
 
 Ebelmen, by heating a mixture of alumina and borax for a long time in a porcelain 
 furnace, obtained a nonobasic salt 3(A1 4 3 )'".B 2 O 3 = 9aTO.B 2 3 or ^ 3 B0 3 .3aTO. 
 
 BORATES OF AMMONIUM. Boric acid forms with ammonia, several salts which may 
 all be regarded as metaborates, expressed by the general formula M n B n 2n , the n at. M 
 being made up partly of ammonium, partly of hydrogen. 
 
 a. (NH 4 ) 3 HB 4 8 is obtained by saturating crystallised boric acid with dry ammonia 
 gas, or by dissolving one of the following salts in warm concentrated aqueous ammonia. 
 The salt obtained by the former process contains 4 at., that by the latter 1 at. water 
 of crystallisation. 
 
 b. (NH 4 )HB 2 4 + |aq. crystallises from a solution of boric acid in excess of am- 
 monia, in very efflorescent crystals of the dimetric system, soluble in 12 pts. of water. 
 It effloresces like the preceding, giving off part of its ammonia. 
 
 c. (NH 4 )H 3 B'0 8 + 2aq. is obtained, according to Arfvedson, by dissolving boric 
 acid in warm caustic ammonia, till the alkaline reaction is nearly neutralised. The 
 liquid, if slowly cooled, deposits rhombic crystals, exhibiting, according to Schabus, 
 the faces oP . P . ooP. oo P GO, and often assuming a prismatic form from the predomi- 
 nance of oP and of four P-faces situated in the same zone ; sometimes twin crystals 
 occur. _ It is permanent in the air, dissolves in 8 pts. of cold water, gives off ammonia 
 on boiling, and leaves boric anhydride when ignited. A salt called Larder cllite, of si- 
 milar constitution, but containing less water of crystallisation, viz. (NH 4 )HB 2 4 '+ Aaq. 
 was found by Bechi in the boric acid formations of Tuscany, in yellowish-whitej 
 transparent, tasteless crystals, exhibiting under the microscope, the form of rectangular 
 
 VOL. I. T T 
 
642 BORON: OXIDE. 
 
 tablets, and by polarised light the optical appearances of gypsum. It dissolves in 
 water, but the solution when evaporated deposits the salt (NH 4 )H 5 B 6 12 + 2 aq. 
 
 d. (NH l )H 4 B 5 IO + faq. (Laurent) + 2aq. (Eammelsberg). First prepared by 
 L. Gmelin, who, however, supposed it to contain 4 at. boric acid to 1 at. ammonia 
 (Handbook ii. 436). According to Rammelsberg, however, it has the composition 
 above given, and is isomorphous with the corresponding potassium-salt. According to 
 Laurent, it is obtained by dissolving excess of boric acid in aqueous ammonia and re- 
 crystallising. It forms small shining prisms of the monoclinic system, generally in 
 cruciform groups. It is permanent in the air, dissolves in about 8 pts. of cold water, 
 and, like the preceding salts, has an alkaline reaction. The solution gives off ammonia 
 when boiled, and the residue solidifies to a granular crystalline mass, which is per- 
 manent in the air, and appears to contain 6 at. boric acid to 1 at. ammonia. 
 
 e. (NH 4 ) 2 H 3 B 5 10 + aq. is obtained by dissolving boric acid in aqueous ammonia. 
 (Arfvedson.) 
 
 A solution of borate of ammonium has been successfully used for rendering muslin 
 and other light fabrics non-inflammable. When tissues thus impregnated are held in 
 the flame of a candle, they are merely carbonised, the water and ammonia which 
 escape preventing the communication of the flame. If the contact with the flame be 
 prolonged, the boric acid melts and forms a glassy varnish round the charred tissue, 
 which prevents it from taking fire. 
 
 BORATE OF AMYL. See BORIC ETHERS (p. 649). 
 
 BORATES OF BARIUM. Boric acid ignited with excess of hydrate of barium expels 
 3 at. water, and forms the tribarytic orthoborate, Ba 3 B0 3 . Heated with excess of car- 
 bonate of barium, it expels 2 at. carbonic anhydride at a dull red heat, and 2| at. at a 
 bright red heat, forming the anhydrous salts, Ba 4 B 2 5 = 2Ba 2 O.B 2 8 and Ba 10 B 4 O n = 
 5Ba 2 0.2B 2 3 . (Bloxam.) 
 
 By precipitating barium-salts with borates of the alkali-metals, borates of barium 
 are obtained, mostly as white crystalline powders, differing in composition according 
 to the composition and relative proportions of the salts employed, the tempera- 
 ture of the solutions, and the duration of the washing. They are probably all 
 metaborates. 
 
 a. Monometaborate, BaBO 2 + 5 aq. (or possibly a monobarytic orthoborate, BaH 2 BO* 
 + 4 aq.), was obtained by Berzelius by precipitating chloride of barium with monoborate 
 
 of potassium. According to H. Eose, when prepared from cold solutions, and dried at 
 100 C. after pressure between paper, but without washing, it has the composition 
 BaBO* + aq., and when precipitated from very hot solutions it contains more than 
 aq., but less than 1 aq. To drive off all the water requires a strong heat. The salt 
 dissolves in cold, and more readily in hot water, especially in presence of ammoniacal 
 salts, and therefore cannot be completely washed. 
 
 b. Sesquimetaborate. Ba 2 HB 3 6 -t- 7 aq. Laurent obtained this salt by mixing a 
 solution of chloride of barium with pentaborate of sodium, under circumstances not 
 particularly specified. According to H. Rose, the precipitate obtained by mixing 
 chloride of barium with an acid borate of alkali-metal, has, when dried at 100 C., the 
 composition Ba 3 H 2 B 5 10 + f aq. 
 
 c. Dimetaborate, BaHB 2 4 + 2aq, is precipitated in white flocks when a solution of 
 nitrate of barium is added by drops to excess of solution of borax mixed with am- 
 monia. It dissolves in 100 pts. of water, more easily in ammoniacal salts and in ex- 
 cess of chloride of barium. (Laurent.) 
 
 d. Trimetaborate. BaH 2 B 8 6 + 6 aq. Precipitated as a white crystalline powder, 
 when a warm solution of nitrate of barium is added by drops and with stirring, to ex- 
 cess of pentaborate of sodium. 
 
 BORATES OF CADMIUM. The precipitate formed on mixing the cold solutions of 
 borax and sulphate of cadmium contains, after being merely pressed, the 'monoborate, 
 CdBO 2 , mixed with a small quantity of an acid salt. The precipitate from boiling 
 solutions consists chiefly of 2CdB0 2 .CdHO + aq. 
 
 BORATES OF CALCIUM, a. Orthoborate. CaH 2 B0 3 (dried at 100 C.) The for- 
 mula might also be that of a monometaborate, CaBO 2 + H 2 0, but the first view of its 
 constitution is the more probable, inasmuch as the salt gives off 1 at. H as water, only 
 at 200 C., and is not completely dehydrated even at 300. It is produced by precipi- 
 tating chloride of calcium with monoborate of sodium, probably also when solution of 
 borax is precipitated by lime-water. It is somewhat soluble in water, and is decom- 
 posed by hot water. 
 
 b. Sisquimctaborate, Ca 2 HB 3 O 8 , appears to be precipitated, together with variable 
 quantities of the dimetaborate, when calcium-salts are mixed with solution of borax 
 (H. Rose). A similar composition appears to belong to rhodicite, a mineral found in 
 the Ural, in small, hard, shining, yellowish-white crystals of tetrahedral habit. It has 
 not been exactly analysed, but appears to contain 4B to 3Ca. (GK Rose.) 
 
BORAXES. 643 
 
 c. Dimetaborate, CaHB 2 4 . Obtained, according to Tiinnermann, when borax is 
 precipitated by nitrate of calcium. It occurs also as a white efflorescence composed of 
 crystalline needles containing f at. water, on the plain of Iquique in Ecuador, South 
 America, forming the mineral called borocalcite, hydroborocalcite, or haycsite (Ulex). 
 Bechi found a calcic diborate with f aq. in an old lagoon-crater in Tuscany. 
 
 d. Tctrametaboratc. CaH 3 B 4 8 + f aq. Precipitated on boiling milk of lime with 
 excess of boric acid. 
 
 Borate of calcium occurs associated with silicate of calcium in botryolite and datolite 
 (q. v.), and with magnesia in hydroboracite (q. v.} 
 
 BORATE OF COBALT is probably contained in the glass fluxes formed with cobalt- 
 compounds and borax. Cold solutions of a cobalt-salt and borax yield a reddish pre- 
 cipitate, which, after drying at 100 C., consists chiefly of 2CoB0 2 .CoHO + faq. It 
 is soluble in water, and melts to a blue glass when strongly heated. 
 
 BORATES OF COPPER. It is difficult to obtain these salts in a definite state. Sul- 
 phate of copper mixed with solutions of alkaline borates, yields precipitates consisting 
 of compounds of borate and oxide of copper mixed with sulphate of soda and basic 
 sulphate of copper, which are decomposed by water, leaving a residue composed of 
 oxide and borate of copper, but with less boric acid than the original precipitate. 
 Cold concentrated solutions of cupric sulphate and monoborate of sodium yield a pre- 
 cipitate which, after washing, consists of CuH0.2CuB0 2 + aq. The precipitate from 
 the same solutions mixed hot is, after washing, CuH0.2CuB0 2 . That obtained in like 
 manner from cold concentrated solutions of cupric sulphate and borax is an orthoborate 
 containing 2 at. copper, viz. (Cu 2 H)B0 3 + 1 aq. The same precipitate is obtained 
 from hot concentrated solutions of cupric sulphate and borax, especially if the copper- 
 salt is in excess. It is a loose blue-green powder, sparingly soluble in water, but de- 
 composed by water, leaving the compound CuB0 2 .3CuHO + iaq. Cold dilute solu- 
 tions of the same salts yield a precipitate containing 5Cu to 2B and 5H, while the pre- 
 cipitate from hot dilute solutions contains 10 or 12 at. Cu to*l at. B. 
 
 Bolley has suggested the use of the green precipitate, obtained from cold solutions 
 of 2 pts. cupric sulphate (blue vitriol), and 3 pts. borax, as a substitute for the 
 arsenical greens used in painting, paper-staining, and calico-printing. 
 
 BORATE OF ETHYL. See BORIC ETHERS (p. 650). 
 
 BORATES OF IRON. Ferric monometaborate, Fe 3 2 .3B 2 3 + 3 aq. or i /eB0 2 + |aq. 
 has not been prepared artificially, but has been found by Bechi in an old lagoon-crater 
 in Tuscany : hence called Lag unite. 
 
 Ferrio. orthoborate, Fe 4 3 .B 2 3 or /e 3 B0 3 , is not known in the separate state, but 
 only in combination with borate of sodium or with ferric oxide. On mixing a solution 
 of ammonioferric sulphate (ammonia-iron-alum) with monometaborate of sodium, a 
 bulky precipitate is formed, which, after being pressed between paper, but not washed, 
 is a soclio-ferric borate containing NaB0 2 .4/e 3 B0 3 + 3 aq. Cold water abstracts boric 
 acid and borate of sodium, leaving an oxyborate, which, after drying at 100 C., is 
 6Fe 4 3 .B 7 3 + 6 aq. or 15/<e 2 0.2/e 3 B0 3 + 6 aq. By precipitating ammonioferric sul- 
 phate with borax, a light brown bulky precipitate is formed containing NaH 5 B 3 6 . 
 4/t 8 B0 3 + aq., and reduced by washing with water to 24/e 2 0.2/e 3 B0 3 + 9aq. or 
 9Fe 4 3 .B 2 3 + 9aq. 
 
 BORATES OF LEAD. a. The monometaborate, PbB0 2 + aq. is obtained, according 
 to Herapath, when the precipitate formed by borax in a neutral lead-salt, is digested 
 for some hours with strong ammonia. It is said also to be produced when a solution 
 of basic acetate of lead is partially precipitated by borax, and, according to H. Rose, 
 by washing with cold water the precipitate formed on mixing the cold solutions of 
 borax and nitrate of lead. It is a white, amorphous, heavy powder, insoluble in water 
 and in alcohol, soluble in dilute nitric and in warm acetic acid, from which solutions 
 it is precipitated by ammonia. It gives off some of its water at 120 C., the whole at 
 160, and at a red heat, melts to a colourless glass, of specific gravity 5'598. 
 
 b. The scsquimetaborate, Pb 2 HB 3 6 + |aq. formed by adding a large excess of borax 
 to a boiling solution of a lead-salt, resembles the preceding, gives off 1 at. water be- 
 tween 170 J and 200 C., and melts to a colourless glass, of specific gravity 5'235. 
 (Herapath.) 
 
 c. Dimetaborate, PbHB 2 4 + 1 aq. obtained by boiling the salt b with borax. Light 
 amorphous powder, which gives off its water between 200 and 230 C., and at a red 
 heat melts to a vitreous mass (Herapath). When 100 pts. lead-oxide are fused with 
 64 pts. boric anhydride (1:2 at.), a nearly colourless glass is obtained as hard as 
 flint-glass, and possessing much higher refractive power. 
 
 Basic borates. According to H. Eose, the precipitates formed with nitrate of lead 
 and either mono- or di-borate of sodium, are frequently basic salts, probably mixtures 
 of monoborate and hydrate of lead, varying in composition according to the strength 
 
 TT 2 
 
644 BORON: OXIDE. 
 
 of the solutions and the duration of the washing. Hot, very dilute solutions, give a 
 precipitate to which Rose assigns the formula 2>(PbO.BO*) + PbO.HO + aq.. or 
 2(3PbB0 2 .PbHO) + aq. 
 
 Borochloride of Lead, PbB0 2 .PbCl-t-^aq, is obtained by mixing hot solutions of 
 borax and chloride of lead, and crystallises in very small, irregular, nacreous needles, 
 which are not decomposed by cold water, but gradually by boiling water. It gives off 
 all its water between 120 and 150 C. 
 
 Boronitrate of Lead, PbB0 2 .PbN0 8 , is deposited in irregular shining crystals, from 
 a solution of borate of lead in nitric acid, evaporated till a film forms on the surface, 
 At 120 C. the crystals give off water and a little nitric acid, and at a higher tempe- 
 rature evolve nitrous acid and melt to a colourless glass. 
 
 BORATE OF LITHIUM. Boric acid heated to bright redness with carbonate of lithium, 
 expels 2| at. carbonic anhydride, forming the salt 5Li 2 0.2B 2 3 . (Bio x am.) 
 
 BOBATES OF MAGNESIUM, a. Orthoborate. Mg 3 B0 3 . Ebelmen obtained this salt 
 by fusing magnesia with boric anhydride, and exposing the vitreous mass, in a plati- 
 num dish, to the strongest heat of a porcelain furnace for several days, till the excess 
 of boric anhydride was volatilised. It formed radiating nacreous crystals, of specific 
 gravity 2'987. It is also obtained as a hydrate, Mg 3 B0 3 + 5aq, by boiling a mixture 
 of borax and sulphate of magnesium, and washing the precipitate (which contains 
 borate of sodium, magnesia, and hydrate of magnesium) with cold water. When boiled 
 with water, it gives up part of its acid, and leaves a basic salt which absorbs carbonic 
 acid from the air. The precipitate formed by boiling sulphate of magnesium with borax, 
 redissolves completely on cooling. 
 
 b. Monomctaborate, MgBO 2 . Obtained as an amorphous precipitate, containing 2 at. 
 water, on mixing the hot solutions of borax and nitrate of magnesium (Laurent). 
 The same salt, but with 4 at. water, was obtained, according to Wohler, when a mixed 
 solution of borax and sulphate of magnesium, which had been heated, and had after- 
 wards become clear by cooling, was left to itself for several months in winter in a 
 place where the temperature often fell below C. It formed slender radiating needles, 
 insoluble in water, soluble in dilute acids, reprecipitated in needles by ammonia, giving 
 off water and becoming turbid when heated. Boracite, from Segeberg in Holstein, 
 appears to be a monoborate of magnesium, while that from Luneburg is a mixture or 
 compound of 3Mg 2 0.4B'-'0 3 , or 6MgB0 2 .B 2 3 , with MgCl. 
 
 c. Trimctaborate, MgH s B 3 6 + 3 aq. separates, according to Rammelsberg, in crys- 
 talline crusts, when a concentrated solution of boric acid is boiled with carbonate or 
 hydrate of magnesium and the filtrate is evaporated. 
 
 d. Tetrametaborate, MgH 3 B'0 8 + aq. This, according to Laurent, is the* compo- 
 sition of the last crops of crystals deposited when a solution obtained by boiling boric 
 acid with magnesium is left to evaporate spontaneously. 
 
 e. Hexmetaborate, MgH 5 B 6 I2 + ^aq. Granular salt obtained by heating hydrate 
 of magnesium with excess of boric acid ; melts to a porcelain-like mass (Rammels- 
 berg). Perhaps a mixture of one of the preceding salts with free boric acid. 
 
 Magnesia-chromic Borate. A salt containing 6Mg 2 0.3Cr < 3 .2B 2 3 , is obtained 
 by heating for five days in the porcelain furnace a mixtnre of 20 grm. chromic oxide, 
 1 5 grm. magnesia, and 20 grm. boric anhydride, being deposited in the cavities of the 
 fused mass in grass-green microscopic crystals, of specific gravity 3*82. (Ebelmen.) 
 
 Magnesio-ferric Borate, 6Mg 2 0.3Fe 4 3 .2B' 2 3 , is obtained by fusing in like 
 manner a mixture of 25 grm. ferric oxide, 20 grm. magnesia, and 25 grm. boric anhy- 
 dride, in small, black, prismatic crystals, of specific gravity 3 '85. 
 
 BOEATE OF METHYL. See BOEIC ETHERS (p. 650). 
 
 BOBATE OF NICKEL. Cold solutions of borax and sulphate of nickel yield a preci- 
 pitate of NiBO 2 + aq. or NiH 2 B0 3 , from which cold water abstracts boric acid, leaving 
 a salt containing 2NiB0 2 .NiHO + 2aq. By boiling for some time with borax, this 
 precipitate is converted into the dimetaborate, NiHB 2 O 4 . 
 
 BORATES OF POTASSIUM. a. The monometaborate, KBO 2 , is formed by melting 
 together 70 pts. (1 at.) boric anhydride, and 138 pts. (1 at.) carbonate of potassium. 
 It melts at a white heat, has a caustic alkaline taste, dissolves in water, and separates 
 slowly from the solution in ill-defined crystals which, according to Schabus, are mono- 
 clinic. The solution should be evaporated out of contact with the air, as it absorbs 
 carbonic acid. Boric anhydride, heated to redness with excer-s of hydrate of potassium, 
 expels 2 at. carbonic anhydride, forming the salt K 4 B 2 5 =* 2K 2 O.B 2 3 . (Bloxam.) 
 
 b. The dimetaborate, KHB 2 4 , is prepared by supersaturating a boiling solution of 
 carbonate of potassium with boric acid, and then adding pure potash in sufficient 
 quantity to produce a strong alkaline reaction. It crystallises sometimes with 2aq. 
 sometimes with 2|aq. The hydrate, KHB 2 4 . -f 2aq., forms regular six-sided prisms, 
 which dissolve readily in water with strong alkaline reaction, and swell up considerably 
 
BORAXES. 645 
 
 when heated. The other hydrate, KHB'0 4 +f aq. : forms right rhombic prisms of 
 98 35', with basic brachydiagonal end-faces. It behaves like the former hydrate, but 
 when kept in a closed vessel, separates into a liquid and a solid salt, apparently the 
 hydrate with 2 aq. 
 
 c. Zrimftaborate, KH 2 B 3 6 + 3 aq. or perhaps, tri-orthoboratc, KH 8 B*0 9 . Obtained 
 like the preceding, but with a smaller quantity of caustic potash. Separates in rect- 
 angular prisms, with four-sided pyramidal summits. Permanent in the air ; melts 
 without much tumefaction. (Ramm els berg.) 
 
 f. Pcntamttaboratc, IvH'IPO 10 + 2aq. Formed when a boiling solution of carbonate 
 of potassium is mixed with a sufficient quantity of boric acid to produce a strong acid 
 reaction. The solution on cooling deposits small shining prisms, isomorphous with 
 the corresponding ammonium-salt. Permanent in the air, sparingly soluble in cold, 
 easily in hot water ; neutral. (Kammelsberg.) 
 
 BORAXES OF SILVER. The precipitates formed in solution of nitrate of silver by 
 alkaline borates vary in composition according to the dilution and temperature of the 
 the solutions. Very dilute solutions, especially if hot, yield a precipitate of pure 
 oxide of silver (H. Rose). A moderately dilute silver-solution mixed with a strong 
 solution of borax, yields a flocculent precipitate of the monometaborate AgBO 2 , which 
 when dry is a white powder blackened by light. It dissolves in a large quantity of 
 water ; but is decomposed by a small quantity ; melts at a gentle heat. The same 
 salt is obtained as a curdy dirty yellow hydrate, AgB0 2 + |aq., on mixing concen- 
 trated solutions of nitrate of silver and monoborate of sodium, or boiling concentrated 
 solutions of silver-salt and borax. It is decomposed by washing with water, especially 
 if hot, which ultimately leaves nothing but oxide of silver. 
 
 Acid borates of silver have not yet been obtained pure. Rose states that cold con- 
 centrated solutions of nitrate of silver and borax yield a white precipitate containing 
 3Ag 2 to 4B 2 O 3 , and after washing with a little cold water, which turns it brown, 
 4Ag 2 to 5B 2 3 . According to Laurent, nitrate of silver yields with pentaborate of 
 potassium, an acid borate of silver which decomposes partially in washing. 
 
 BORAXES or SODIUM. Boric anhydride fused with excess of hydrate of sodium 
 expels 3 at. water and forms trisodic orthoborate, Na 3 B0 8 . 
 
 B 2 0' + 6NaHO = 3II 2 + 2Na 3 BO 
 
 (Bloxam, Chem. Soc. Qu. J. xiv. 143). Fused with excess of carbonate of sodium at a 
 bright red heat, it expels If at. carbonic anhydride and forms: Na 6 B 4 9 or 3Na 2 0.2B 2 0*. 
 
 2B 2 3 + 3Na 2 C0 3 = Na 6 B 4 9 + 3C0 2 . 
 
 (Arfvedson, Gmelin's Handbook, iii. 87 ; compare Bloxam, Chem. Soc Qu. J. xii. 
 186). By fusing borax with excess of carbonate of sodium, Arfvedson found that 1 at. 
 anhydrous borax expelled 3 at. carbonic anhydride producing a dibasic borate of 
 sodium or tetrasodic borate : Na 4 B 2 O 5 or 2Na 2 O.B 2 O s : 
 
 Na 2 0.2B 2 3 + 3(Na 2 O.C0 2 ) = 3C0 2 + 2(2Na 2 O.B 2 8 ), 
 
 1 at. carbonate of sodium fused with 1 at. boric anhydride yields anhydrous mono- 
 metaborate of sodium, NaBO 2 or Na'-'O.B 2 3 , and with 2 at. boric acid anhydride, it 
 yields anhydrous acid borate of sodium, Na 2 B 4 7 = Na 2 0.2B-W = 2NaB0 2 .B-'O 8 . 
 The aqueous solutions of both these salts yield crystalline hydrates which might be 
 regarded either as orthoborates or metaborates, but are most probably the latter. 
 Respecting the behaviour of the tri- and tetrasodic borates in the hydrated state, 
 nothing appears to be known. 
 
 Monometaborate or Neutral Borate of Sodium, NaBO 2 , is produced by heat- 
 ing 62 pts. of crystallised boric acid, or 191 pts. crystallised borax, with 53 pts. of anhy- 
 drous carbonate of sodium at a heat near the melting point of silver. The unfused mass 
 thus obtained dissolves in water, with rise of temperature ; and by cooling the hot but 
 not saturated solution, the hydrated salt NaB0 2 + 4aq. (or possibly Na s B0 3 + 3aq.) 
 crystallises in large oblique rhombic prisms with lateral angles of 130 and 70. 
 It has a caustic alkaline taste, and quickly absorbs carbonic acid from the air, both in 
 the solid state and in solution ; but on boiling the solutions, the carbonic acid escapes 
 At 57 C. it melts in its water of crystallisation, and after the liquid has cooled for 
 some time, the hydrate NaBO 2 + 3aq. separate in indistinct crystals. At a stronger 
 heat, it gives off all its water, and forms a friable tumefied mass, which absorbs 
 carbonic acid from the air. 
 
 Dimetaboratt or Acid Mctaborate of Sodium. Na 2 B 2 7 = 2NaB0 2 .B 2 3 , or 
 NuO.IBO*. Biborate of Soda. Borax. This salt is obtained in the anhydrous state 
 by fusing 124 pts. crystallised boric acid with 53 pts. anhydrous carbonate of sodium, 
 or by heating crystallised borax. (A process for obtaining borax on the large scale by 
 
 T T 3 
 
646 BORON: OXIDE. 
 
 heating boric anhydride with carbonate of sodium has been patented by Sattlter 
 Nov. 20th, 1843). In contact with water, it passes into the hydrated state, and 
 crystallises from its aqueous solution, either with 5 or with 10 at. water, according to the 
 temperature. The former hydrate is octahedral borax; the latter, prismatic or 
 ordinary borax. 
 
 Borax is found native in several localities, viz. at Halberstadt in Transylvania, at 
 Viquintizoa and Escapa in Peru, in the mineral springs of Chambly, St. Ours, &c 
 Canada West, but more particularly in certain salt lakes of India, Thibet, and other 
 parts of Asia, whence the greater part of the borax of commerce was formerly obtained. 
 The salt separated from these waters by evaporation, either natural or assisted by 
 artificial contrivances, is sent to Europe as crude borax or tinea 1, sometimes in 
 large regular crystals, but more frequently as a white or yellowish-white mass, which 
 is very impure, containing lime, magnesia, and alumina, and likewise covered over 
 with a greasy substance (said to be added to diminish the risk of breakage during 
 transport). According to analyses by Richardson and Browell, crude Indian borax 
 contains : 
 
 Boric acid (anhydrous) . . . 22-88 40'24 24-41 
 
 Soda .... 12-59 11-11 11-71 
 
 Chloride of sodium .... 0*92 0-11 0'21 
 
 Sulphate of sodium .... 0'13 0*49 2*84 
 
 Sulphate of calcium .... T36 0'68 1-36 
 
 Insoluble matter 17'62 1'37 20-02 
 
 Water 44-50 46-QO 39-45 
 
 100-00 100-00 100-00 
 
 The purification or refining of this crude Asiatic borax has been carried on from 
 very early times in various seaport towns of Europe, especially at Venice, and more 
 lately at Amsterdam. Great pains have always been taken to keep the process secret, 
 but two methods, one with lime and the other with soda, have become known : 1. The 
 tincal is macerated in a small quantity of cold water, and stirred about, with gradual 
 addition of 1 per cent, of slaked lime, the turbid lime-water being poured off from 
 time to time, and when it has clarified, again poured upon the crystals. This treat- 
 ment removes the greater part of the soapy compound, and the rest is decomposed by 
 adding 2 per cent, of chloride of calcium to the solution of the crystals in hot water. 
 The insoluble lime-soap thus formed, is removed by straining, and the clear liquid is 
 evaporated to the density of 21 Beaume. 2. The powdered tincal is placed in a 
 tub with holes in the bottom, and washed with a solution of caustic soda of specific 
 gravity T034, then drained and dissolved in water, and 12 per cent, of soda added 
 to precipitate the earths, after which the solution is strained and evaporated. The 
 crystallisation is effected in wooden vessels lined with lead, having the form of short 
 inverted cones. 
 
 The greater part of the borax used in the arts, is now prepared in France by treat- 
 ing the native boric acid of Tuscany with carbonate of sodium, according to a method 
 first practised by Payen and Cartier. 1300 kilogrammes of crystallised carbonate 
 of sodium are dissolved in 1500 litres of water in a wooden vessel lined with lead ; 
 the liquid is heated to the boiling point by a jet of steam, and 1200 kilogrammes 
 of crystallised boric acid are added. The density of the solution varies according 
 to the degree of purity and dryness of the boric acid used ; it is brought to a certain 
 strength by adding borax or water as required, then left at rest till the insoluble 
 matters have settled down, and finally transferred to the crystallising vessels, which 
 are rectangular wooden boxes lined with lead, 6 metres long, 1*7 met. wide, andO'5 met. 
 deep. ' The formation of prismatic or of octahedral borax, depends upon the density 
 of the solution, and the temperature at which the crystallisation takes place. 
 
 a. Prismatic or Ordinary Borax, NaHB 2 4 + f aq. or 2NaHB"0 4 + 9 aq. or NaO.ZBO* 
 + I0aq. To obtain this hydrate, the solution, after all the carbonic acid has escaped, 
 should have a density of 21 or 22B. (specific gravity T14 to T15), and should boil 
 at 104 C. (220 F.) It is left to crystallise for two or three days, the crystallisation 
 being finished when the thermometer in the interior of the vessels stands at 25 to 
 30 C. (77 to 86 F.) The crystals thus obtained, are freed from mother-liquor, then 
 dissolved in boiling water together with i of their weight of crystallised carbonate 
 of sodium, to separate any remaining earths, and the strained liquid is concentrated to 
 21 or 22 B. and left to crystallise as before. The mother-liquor is then drawn off 
 us rapidly as possible with wide syphons, and that which remains amongst the angles 
 of the crystals is soaked up with sponges, so that no small crystals may deposit upon 
 the larger ones. The whole is then covered and left at rest for several hours, to avoid 
 the formation of cracks in the crystals, which would be occasioned by the access cf 
 cold air. 
 
BORAXES. 647 
 
 The mother-liquor is diluted with water and used in a subsequent operation for 
 dissolving the boric acid and carbonate of sodium. After three or four operations, it 
 contains a considerable quantity of sulphate of sodium ; but on cooling it to 30 C. 
 (86 F.), borax crystallises out alone, the sulphate remaining in solution. The last 
 mother-liquors yield by evaporation an impure borax, which is used in glass-making. 
 
 Considerable quantities of borax are also prepared from the native borate of calcium 
 and sodium (Boronatro-calcite), from South America, by decomposing it with carbonate 
 of sodium, either in the wet or in the dry way. 
 
 Artificial borax is for the most part purer than that obtained from native tincal by 
 the refining process, but the crystals often contain cracks, and split when heated, in 
 the direction of their natural cleavage, which is a great inconvenience when the borax 
 is used for soldering, as it causes the crystals to fly off from the surface of the metal. 
 This fault is partially corrected by slow recrystallisation from a rather concentrated 
 solution ; but it is more effectually remedied by the addition of a small quantity of 
 tincal before recrystallisation. (For further details of the manufacture of borax, 
 see Urc's Dictionary of Arts, Manufactures, and Mines, i. 379 ; Handwb'rterbuch der 
 Chemie, 2 te Aufl. ii. [2] 320 ; Precis de Chimie industriette par A. Pay en, 4 me ed. i. 436.) 
 
 The impurities generally found in artificial borax, are carbonate of sodium, small 
 quantities of sulphates, chlorides, and salts of calcium and magnesium. It is some- 
 times purposely adulterated with alum and common salt. It should dissolve in about 
 2 pts. of hot water, and exhibit no effervescence when treated with acids. The aqueous 
 solution should remain perfectly clear on addition of alkali, and when acidulated 
 with nitric acid, should not be clouded either by chloride of barium or nitrate of 
 silver. 
 
 The proportion of soda in borax may be estimated by colouring the solution with 
 litmus, and adding a standard solution of sulphuric acid, till a bright red colour is 
 produced (p. 631), and from the amount of alkali thus determined, the quantity of 
 boric acid may be calculated. 
 
 Prismatic borax forms large transparent prisms, of the monoclinic system, generally 
 combinations of a nearly rectangular prism, having the acute and obtuse lateral edges 
 truncated. The crystals effloresce in the air (according to Sims, only when they con- 
 tain carbonate of sodium). When heated, they melt in their water of crystallisation, 
 swelling up considerably, and solidifying to a loose spongy mass called burnt or cal- 
 cined borax (Borax usta)-, at a red heat, the salt fuses to a colourless anhydrous 
 glass of specfiic gravity 2'36, called vitrified borax. This, if pulverised and ex- 
 posed to the air, gradually absorbs 10 at. water, reproducing ordinary prismatic borax. 
 
 . Borax with 6 at. water, Na 2 0.2B 2 3 + 6 aq. or NaHB 2 4 + faq. Found by 
 Bechi in an old lagoon crater ; not yet obtained artificially. 
 
 7. Borax with 5 at. water. Octahedral Borax, Na 2 O.B 2 3 + 5 aq. or NaHB 2 4 + 2aq. 
 (or possibly NaH 5 B 2 6 ). To obtain this salt, the solution (p. 646), is concentrated 
 to a strength of 30 B (specific gravity 1-246), and left to cool very slowly in a warm 
 place. The crystallisation begins at 79 C. (174 F.), and as soon as the temperature 
 of the liquid has fallen to 56 C. the mother-liquor must be quickly withdrawn, because 
 at that temperature prismatic borax begins to crystallise out. After a .few hours, the 
 crusts of the octahedral salt are removed and dried in the air. The crystals are 
 regular, transparent octahedrons, harder and less fragile than ordinary borax ; they 
 have a conchoi'dal fracture, and specific gravity = 1'8. They are unalterable in dry 
 air, but in a moist atmosphere, they absorb water, and are converted into prismatic 
 borax. When heated, they fuse to an anhydrous glass with less intumescence than 
 common borax, and without splitting. On this account, octahedral borax is better 
 adapted than common borax for many purposes, as for soldering and as a flux ; its 
 smaller proportion of water (30 per cent., that of common borax being 47 per cent.) 
 also diminishes the cost of transport. Nevertheless, prismatic borax is generally pre- 
 ferred by consumers, probably because they are used to it, and it is sold at a lower 
 price, weight for weight. 
 
 5. Amorphous Borax, NaHB 2 4 + aq. Obtained by evaporating a solution of borax 
 at 100 C. 
 
 Borax is easily soluble in water, but insoluble in alcohol. Poggiale found that 100 
 parts of water at various temperatures, dissolve the following quantities of prismatic 
 borax: 
 
 at C. . . 2-8 pts. at 50 C. . . 27'4 pts. 
 
 10 . 4-6 60 .. 40-4 
 
 20 . 7'9 70 .. 57-8 
 
 30 . . 11-9 80 . . 76-2 
 
 40 . . 17-9 90 . . 119-7 
 
 and at the boiling heat, 201 - 4 parts. 
 
 TT 4 
 
648 BORON: OXIDE. 
 
 The aqueous solution has a slight alkaline reaction, and changes the light yellow 
 colour of an alcoholic solution of turmeric to brown : on adding a small quantity of 
 sulphuric acid, the yellow colour is restored ; but a larger addition of sulphuric acid 
 sets the boric acid free, which then produces the peculiar red-brown colouring already 
 mentioned (p. 639). 
 
 Borax is easily decomposed by acids. Even water, when present in considerable 
 quantity, abstracts part of the base, so that a dilute solution of acid borate of sodium 
 reacts like a mixture of boric and the neutral borate, or even free soda, giving, for 
 example, a brown precipitate with silver-salts (p. 641). A solution of borax evapo- 
 rated with excess of hydrochloric acid leaves a mixture of chloride of sodium and free 
 boric acid. It also absorbs carbonic acid when exposed to the air, or when the gas 
 is passed into it, and on adding alcohol to the liquid, when saturated with carbonic 
 acid, no borax separates from it. A solution of borax saturated with sulphuretted 
 hydrogen, and mixed with alcohol, separates, on addition of ether, into two layers, the 
 lower containing sulphide of sodium, the upper free boric acid. 
 
 Borax forms with many of the weaker acids, double salts in which the boric acid 
 appears to act as a base to the other acid. Thus, with arsenious acid it forms a com- 
 pound whose empirical formula is 3Na 2 0.6B 2 O 3 .5As 2 3 + lOaq. It unites also with 
 fluoride of sodium (see p. 633). When 1 at. tartaric acid is mixed in solution with 
 2 at. borax, boric acid separates out on cooling ; if the quantity of tartaric acid be 
 gradually increased, the quantity of boric acid separated likewise increases up to a 
 certain point ; but beyond that it diminishes, and at last no further separation of boric 
 acid takes place. Here also the boric acid seems to play the part of base towards the 
 tartaric acid (see TARTBATES). Acid tartrate of potassium also forms a double salt 
 with borax. Of silicic acid, a solution of borax dissolves but a mere trace. 
 
 Benzoic, tannic, and gallic acids dissolve in borax-solution more readily than in 
 water. Many insoluble substances, e.g. stearic and other fatty acids, colophony, 
 shellac, and other resins, dissolve in borax-solution as readily as in weak alkaline leys, 
 the solution acting in fact just like a mixture of boric acid and free alkali. 
 
 At a red heat, on the other hand, the boric acid in borax readily unites with and 
 dissolves metallic oxides, forming fusible double salts : hence the great use of borax 
 in metallurgic and assaying operations, and for soldering. The compounds thus 
 formed often take the form of transparent glasses of various colours, affording very 
 characteristic and delicate tests for the several metals : hence the use of borax in 
 blowpipe analysis. It is also used in the formation of easily fusible glass fluxes for 
 enamels and glazes. An enamelled coating for cast-iron vessels is made by first fusing 
 on the surface of the metal, a mixture of quartz, felspar, clay, and borax, and then 
 covering it with a glaze containing borax. A glazing of 1 pt. clay, 1 pt. felspar, and 
 2 pts. borax is also used instead of lead-glazing for stone-ware. 
 
 Borax is likewise used, though not to any great extent, in medicine, either directly 
 as a remedy, external or internal, or for the formation of pharmaceutical preparations, 
 such as tartarised borax. 
 
 c. Tetrametaborate of Sodium. NaH s B 4 8 + aq. Produced by boiling 2 at. 
 borax with 1 at. chloride of ammonium, as long as ammonia continues to escape: 
 
 2NaHB0 4 + NH 4 C1 = NaH 3 B 4 8 + NaCl + NH 8 . 
 
 It separates from the filtrate by slow evaporation in milk-white, transparent, shining, 
 hard crystalline crusts ; dissolves in 5 to 6 pts. water of mean temperature, forming an 
 alkaline solution ; yields a precipitate of boric acid on addition of a dilute acid, whereby 
 it is distinguished from borax ; melts when heated, with less tumefaction than ordinary 
 borax. (Bolley, Ann. Ch. Pharm. Ixviii, 122.) 
 
 d. Pentametaborate. NaH'B 5 10 -t faq. Prepared by dissolving 1 at. borax 
 and 3 at. boric acid in hot water, and separates from the solution in small crystals 
 aggregated in roundish masses ; they do not suffer any loss of weight at 100 C., and 
 give off their water of crystallisation but slowly at higher temperatures. The salt 
 to which Laurent assigned the empirical formula Na 10 B 48 77 + 55 aq. is perhaps this 
 pentaborate. 
 
 e. Hexmctaborate. NaH 5 B 8 12 . Not yet obtained in the solid form, but perhaps 
 contained in the solution produced by mixing 3 at. borax dissolved in water with 1 at. 
 sulphuric acid : 
 
 3NaHB 2 + H 2 S0 4 = Na 2 S0 4 + NaH 5 B B 12 . 
 
 This liquid thus formed does not redden litmus ; but if 1 at. more of sulphuric 
 acid be added, all the boric acid is set free, and the mixture exhibits the wine-red 
 colour thereby produced, which, however, another drop of sulphuric acid immediately 
 changes to bright-red (Laurent, Ann. Ch. Phys. [2] Ixvii. 218). The hexborate 
 
BORATES. 649 
 
 is perhaps also formed when aqueous borax is mixed with boric acid till the liquid no 
 longer exhibits a basic reaction. This solution is said to yield by evaporation 
 tabular crystals, having a cooling taste like nitre, a neutral reaction, and giving off 30 
 per cent, water when melted. (Tunnermann.) 
 
 Borate of Sodium and Calcium. NaCaH 2 B 4 8 + 9aq. Such, with addition 
 of 1-9 per cent, chloride of calcium, is, according to Helbig (Chem. Centr. 1858, p. 
 494), the composition of a mineral from South America, known in commerce as 
 ' borate of lime," and forming irregular nodules, mainly composed of a net-work ol 
 translucent crystals. Stein regards it as identical with the hydroborocalcite of Hayes 
 and the boronatrocalcite (q. v.} of Ulex. 
 
 Borate of Sodium and Magnesium. NaMg 2 H 2 B 5 10 + 14aq. (Eammelsberg). 
 Separates by spontaneous evaporation, from a mixture of the cold aqueous solutions of 
 borax and sulphate of magnesium, in large, shining, efflorescent, monoclinic crystals. 
 It dissolves in cold water, forming an alkaline solution which is not precipitated by 
 ammonia, but becomes turbid when boiled, clear again on cooling. If the liquid, after 
 boiling for some time, be quickly filtered, the residue consists of basic borate of mag- 
 nesium. 
 
 BOEATES OF STRONTIUM. 1. Orthoborate, Sr 3 B0 3 . Obtained by heating boric 
 anhydride to redness with excess of hydrate or carbonate of strontium. (Bloxam, 
 Chem. Soc. Qu. J. xii. xiv. 142.) 
 
 2. Mctaboratcs. The monoborate has not been obtained. Strontium-salts, pre- 
 cipitated by borax in the cold, yield a precipitate, which when pressed between paper 
 and dried at 100C., has the composition Sr s H 2 B 8 10 + |aq, gives off 2 at. water at 
 200, and the rest at 300, and is partially decomposed by hot water, the residue pro- 
 bably consisting of the sesquiborate, Sr 2 HB 3 6 . 
 
 The dimetaborate, SrHB 2 4 + |aq. (at 100 C.), is said to be precipitated from boil- 
 ing solutions of borax and chloride of strontium. It has an alkaline reaction ; dis- 
 solves in 130 pts. of pure water, more easily in presence of ammoniacal salts ; gives off 
 3 at. H as water at 280, the remaining atom at a red heat, leaving the anhydrous 
 saltSr-Br^O 7 = Sr-'0.2B0 8 ( = 2SrHB 2 4 -H 2 0). 
 
 The titramctaboratc, SrH 3 B 4 8 + aq. is obtained, according to Laurent, by boiling 
 the preceding with excess of boric acid, and evaporating the filtrate. Pentaborate 
 of potassium also precipitates strontium-salts, but the precipitate has not been 
 examined. 
 
 BORATE or ZINC. Sulphate of zinc, precipitated by borax in the cold, yields a pre- 
 cipitate consisting chiefly of monoborate of zinc, ZnBO 2 , which, however, is decomposed 
 by washing with cold water, leaving a basic salt = 4ZnB0 2 .5ZnHO + 2aq. (at 100 C.) 
 A solution of a zinc-salt, mixed at the boiling heat with borax and boiled for some 
 time, yields a precipitate consisting of a similar basic borate, mixed with basic sulphate 
 of zinc. 
 
 Boric Ethers. 
 
 BORATES OF AMYL. a. Orthoborate. (C 5 H n ) 3 B0 3 (Ebelmen and Bouquet, 
 Ann. Ch. Phys. [3] xvii. 61). Produced by the action of chloride of boron on amylic 
 alcohol : 
 
 3(C 5 H".H.O) + BC1 3 = 3HC1 + (C 5 H) 3 B0 3 . 
 
 When vapour of chloride of boron is passed into amylic alcohol, hydrochloric acid is 
 evolved, and the liquid quickly separates into two layers, the upper of which, when 
 decanted and distilled, passes over almost wholly between 260 and 280 C., and when 
 again rectified, yields pure tri-amylic borate. It is a colourless, oily liquid, having a 
 specific gravity of 0'87 at C., and a faint odour like that of amylic alcohol ; it burns 
 with a green-edged flame, and boils between 270 and 275 C. Vapour-density, by 
 experiment, = 10'55 ; by calculation (2 vol.) = 9'45. Water decomposes it, yielding 
 boric acid and amylic alcohol. 
 
 b. The metaborate of amyl, C 5 H U B0 2 , has not yet been obtained. 
 
 c. Acid borate, 2C S H"B0 2 .B 2 3 or (C S H) 2 0.2B 2 3 (Ebelmen, Ann. Ch. Phys. 
 [3] xvi. 139), is obtained by pouring 2 pts. of amylic alcohol on 1 pt. of boric anhy- 
 hydride, heating the mixture to about 180 C., exhausting it with anhydrous ether, 
 distilling off the ether from the decanted ethereal solution, and heating the residual 
 liquid to 250270 C., to free it from fusel-oil. The acid amylic borate thus ob- 
 tained, is a clear, slightly yellowish liquid, having an odour like that of fusel-oil. It 
 may be heated to 300 C. without alteration, but is decomposed at higher tempera- 
 tures. It burns with a green flame. 
 
 When fusel-oil is heated to 300 C. with excess of boric anhydride, a colourless liquid 
 passes over, which smells like amylic alcohol, and begins to boil below 100; but the 
 
650 BORON: OXIDE. 
 
 boiling point rises quickly, and there remains a vitreous mass, resembling the acid ether. 
 As acid borate of methyl gives off oxide of methyl by dry distillation, it is probable 
 that the lighter products of the distillation just mentioned contain oxide of amyl. 
 
 EQUATES OF ETHYL, a. Orthoborate. (C-II 5 ) 3 B0 3 . (Ebelmen and Bouquet, 
 Ann. Ch. Phys. xvii. 55; Bowman, Phil. Mag. [3] xxix. 546.) Prepared like the 
 corresponding amyl-compound. Vapour of chloride of boron is rapidly absorbed by 
 absolute alcohol, the liquid becoming hot and separating after a while into two layers, 
 the lower of which is merely alcohol containing hydrochloric acid, while the upper 
 contains the tri-ethylic borate, which may be separated by distilling the decanted 
 liquid, with addition of a little alcohol, collecting that which passes over between 
 115 and 125 C., and rectifying. It is likewise produced by distilling a mixture of 
 dry ethylsulphate of potassium and anhydrous borax. (H. Eose, Pogg. Ann. xcviii. 
 245.) _ See also vol. ii. p. 628. 
 
 It is a colourless, mobile liquid, having a peculiar, agreeable odour, and burning 
 bitter taste. Specific gravity 0'885. It dissolves in all proportions in alcohol and 
 ether, mixes with water, but is decomposed thereby in a few minutes, with separation 
 of boric acid. Boiling point 119 C. Vapour-density (by experiment) = 5'14 ; by 
 calculation (2 vol.) == 5*07. Burns with green flame, giving off white fumes of boric 
 acid, and leaving no residue. 
 
 Mctaborate, or Neutral Borate, C 2 H 5 B0 2 . Produced, with separation of boric 
 acid, by the action of alcohol on the acid borate : 
 
 2C 2 H 5 B0 2 .B 2 3 + C 2 H 5 .H.O = 3C 2 H 5 .B0 2 + HBO 2 . 
 
 Acid borate of Alcohol. Metaborate Boric 
 
 ethyl of ethyl. acid. 
 
 When the syrupy acid ether is mixed with absolute alcohol, boric acid separates, 
 with considerable evolution of heat, and on separating the liquid therefrom by decan- 
 tation and pressure, and heating it for a while to 100 C., boric acid is again deposited, 
 and there remains a colourless mobile liquid, which resembles the orthoborate, and 
 yields by analysis 32-93 per cent, carbon and 6'97 hydrogen, the formula requiring 
 33-38 C, and 6'96 H. (Handw. ii. [2] 309.) 
 
 Acid Borate. 2C 2 H a B0 2 .B'-0 3 =- (C 2 H 5 ) 2 0.2B 2 3 . Biborate of Ethyl (Ebelmen, 
 Ann. Ch. Phys. [3] xvi. 129.) Produced by the action of boric anhydride on alcohol. 
 When finely pulverised boric anhydride is mixed with an equal quantity of absolute 
 alcohol at 18 C. the mixture becomes hot, quickly attaining the temperature of 50, 
 and begins to boil when heated to 95. If the distillation be interrupted as soon as 
 the boiling-point rises to 110, the distilled portion poured back, and the distillation 
 repeated till the boiling-point again rises to 110, acid borate of ethyl remains in the 
 retort, mixed with boric acid, from which it may be separated by digesting the residue 
 for twenty-four hours with anhydrous ether, decanting from the undissolved portion, and 
 distilling till the heat in the retort rises to 200, Acid borate of ethyl then remains 
 in the form of a thick yellowish liquid, which gives off white fumes in the air at 200, 
 and solidifies on cooling to a transparent glass. This glass is rather soft, even at 
 mean temperatures, and at 40 or 50 may be drawn out into long threads. It has a 
 faint ethereal odour, a burning taste, and blisters the skin, being at the same time 
 converted into a white powder of boric acid. It gave by analysis, 19*8 per cent. C, 
 4-4 H, and 667 B 2 3 , the formula requiring 22'5 C, 47 H, and 65'3 B 2 a . 
 
 Acid borate of ethyl begins to decompose at 300 C. with fusion, intumescence, and 
 thickening, the products being ethylene-gas, alcohol-vapour, vapour of the undecom- 
 posed ether, vapour of water, and fused boric anhydride free from charcoal. The 
 ethylene-gas burns with a green flame, the colour arising from admixed boric ether, 
 which, however, may be removed by washing the gas with water. 
 
 The acid ether becomes very hot by trituration with water, being resolved into 
 alcohol, and boric acid. Exposed to moist air, it becomes white on the surface from 
 slow decomposition. It dissolves in alcohol and in ether, but gives off these liquids com- 
 pletely at 200 C., a portion of the undecomposed boric ether then passing over with the 
 alcohol so that the distillate burns with a green flame, and when mixed with water 
 solidifies from separation of boric acid. The syrupy acid ether treated with absolute 
 alcohol in the manner above described, yields the neutral borate of ethyl. 
 
 BORATES OF METHYL. a. Orthoborate. (CH 3 ) 3 B0 3 (Ebelmen and Bouquet, Ann. 
 Ch. Phys. [3] xvii. 59.) Produced by the action of chloride of boron on anhydrous 
 methylic alcohol ; purified by rectifying the upper of the two resulting layers of liquid. 
 It is a colourless mobile liquid of specific gravity 0'955 ; has a pungent odour some- 
 what like that of wood-spirit ; boils at 72 C. Vapour-density = 3'66. Dissolves 
 in alcohol and ether, is quickly decomposed by water, and burns with a green flame. 
 
 b. Acid3orate2CR*BCKB*O t = (CH 3 ) 2 0.2B-'0 3 (Ebelmen, Ann. Ch. Phys. [3] 
 xvi. 137.) Obtained, like the acid ethylic borate, by treating boric anhydride with 
 
BORON: SULPHIDE BE AGITE. 651 
 
 anhydrous methylic alcohol. The mass is repeatedly heated to 110 C., the distillate 
 being each time poured back, the residue is treated with ether, and the decanted 
 solution heated to 200. Acid borate of methyl is thus obtained as a vitreous 
 mass, soft and tenacious at ordinary temperatures. It burns in the air with a 
 beautiful green flame ; is decomposed by distillation into boric anhydride and oxide 
 of methyl ; and by water, into boric acid and methylic alcohol. 
 
 BORON, SULPHIDE OP. B 2 S 3 . This compound, which is the analogue of 
 boric anhydride, is formed by igniting boron in vapour of sulphur (Berzelius, Pogg. 
 Ann. ii. 145) or in sulphuretted hydrogen; also by heating boron with sulphide of 
 lead (Wohler and Deville, Ann. Ch. Pharm. cv. 72), or by heating a mixture of boric 
 anhydride and charcoal in vapour of sulphide of carbon (Fremy, Ann. Ch. Phys. 
 [3] xxxviii. 819), or by strongly heating a borate in vapour of sulphide of carbon 
 (Skoblikoff and Kudloff, Petersb. Acad. Bull. xii. 319). To obtain a pure product, 
 boron is heated in sulphur vapour as long as that vapour continues to be absorbed by 
 it. The action is slow, because the sulphide forms a crust round the boron. 
 
 Pure sulphide of boron is a white solid body, sometimes amorphous, sometimes 
 crystalline. It has a pungent sulphurous odour, like that of chloride of cyanogen, 
 or chloride of sulphur. Its vapour attacks the eyes. By itself it does not appear to 
 be volatile,' but it volatalises in sulphuretted hydrogen, like boric acid in vapour of 
 water. Heated in a stream of hydrogen, it melts, and gives off a little sulphur, perhaps 
 however, only when not quite pure. It decomposes water with great energy, forming 
 lx>ric and sulphydric acids, a decomposition to which, as already observed, the formation 
 of boric acid in the Tuscan lagoons has been ascribed. 
 
 There appears also to be a persulphide of boron, produced by heating boron in 
 sulphur- vapour till it takes fire, and then leaving it to cool in the vapour. When the 
 product thus obtained is thrown into water, boric and sulphydric acids are formed, and 
 milk of sulphur is deposited. (Berzelius.) 
 
 BORONATROCAX.CITE. NaCa 2 H 3 B 6 18 + ^ aq. Native borate of calcium 
 and sodium, called also Hydroboratite, Haycsin. and Tiza. (See BORATES or SODIUM, 
 p. 649.) 
 
 BOTRirOGXroTj Red vitriol. A native ferroso-ferric sulphate from Fahlun in 
 Sweden, occurring rarely in small oblique rhombic prisms, having the lateral faces 
 inclined to each other at an angle of 119 56', and to the terminal faces at 113 C 37'; more 
 frequently massive and as a deposit on gypsum, sulphate of magnesium, ferrous sulphate, 
 and iron pyrites. Translucent, with vitreous lustre. Dark hyacinth-red to ochre-yellow, 
 Harder than gypsum. Specific gravity 2'039. Swells up before the blowpipe, giving 
 off water and leaving feme oxide. According to Berzelius, its formula is 3Fe 2 0.2S0 3 
 + 3(Fe 4 8 .2S0 8 ) + 36H a O. 
 
 BOTRYCLITE. Chaiuc boratee silicieuse concretionee. 2CaB0 2 .Ca 2 Si 2 5 -f 2 aq. 
 A kidney-shaped mineral of delicate fibrous texture, found in the veins of magnetic 
 iron ore at Arendal in Norway ; generally as a deposit on crystals of calcspar. Its 
 formula is the same as that of date-lite, but with twice the amount of water. 
 
 BOin,AKTGE3lIT3. A tribasic sulphantimonite of lead, 3Pb 2 S.Sb 2 S 3 or SbPb 3 S ! , 
 found at Molieres in France, in Lapland, and other localities. Crystallo-laminar or 
 fine-grained. Dark lead-grey. Specific gravity 5'59 to 5'97. 
 
 BOUK.NOTJITE. Schwarzspicssglanzerz. Antimoine plombo-cupriferc: 2Pb 2 S. 
 
 Cu 2 S.Sb 2 S 3 = SbPb 2 CuS 3 . Crystallises in right rectangular prisms of dark steel-grey 
 colour, with metallic lustre, and yielding a black powder. Hardness equal to that of 
 calcspar. Specific gravity 5*7 to 5'S. Melts before the blowpipe, giving off white 
 fumes, covering the charcoal with oxide of lead, and changing to a slag containing a 
 large quantity of copper. It is found in the copper mines of Cornwall, at Neudorf 
 and Andreasberg in the Harz, at Kapnik and Offenbanya in Transylvania, &c., but is 
 not very abundant. Some varieties found near Freiberg contain silver to the amount 
 of about 0-12 per cent. (Gm. v. 486.) 
 
 BO VF.TT COAXi. A kind of coal of a brown or brownish-black colour and lamellar 
 textur^, the lamina being often flexible when first dug out, but generally hardening by 
 exposure to the air. It consists of wood penetrated with petroleum or bitumen,"and 
 frequently contains pj'rites, alum, and protosulphate of iron. By distillation, it yields 
 a fetid liquor mixed with ammonia and an oil partly soluble in alcohol. It 'is found 
 in England, France, Italy, Switzerland, Germany, Iceland, &c. 
 
 BOWENTTE. See SERPENTINE. 
 
 BOYX.ZTS FUIVXXITG LIQUOR. Monosulphide of Ammonium (p. 193.) 
 
 BRAGXTE. A mineral found at Arendal in Norway, but not yet sufficiently ex- 
 amined to establish its separate identity. (Forbes and D ahll, J. pr. Chem. Ixvi. 446.) 
 
652 
 
 BRAIN BRANDY. 
 
 BRAIN. See NERVOUS TISSUE. 
 
 BRANT. Son. Klcie. (Mi 11 on, Ann. Ch. Phys. [3] xxvi. 5. Pe" ligot, ibid. xxix. 
 5. Kekul6, Liebig's cliem. Briefe, 3 Aufl. i. 595. Wetzel and Van Hees, Arch. 
 Pharm. [2] Ixvii. 284. Poggiale, Compt. rend, xxxvii. 171; xlix. 128. Sigle, 
 Dingl. pol. J. cxxxi. 298. Mouries, Compt. rend, xxxvii. 351 ; xlvii. 505; xlviii. 
 431. Oudemans, Kep. chim. app. i. 585.) -The husky portion of ground corn, 
 separated by the boulter from the flour. The analyses which have been made of it, 
 even from the same kind of corn, differ widely in the proportion of some of the essen- 
 tial constituents, as the following table will show. 
 
 Ash 
 
 Rye- 
 bran. 
 
 Wheat-bran. 
 
 Oude- 
 mans. 
 
 Oudemans. 
 
 Poggiale. 
 
 K<5kul<5. 
 
 Mil Ion. 
 
 3-35 
 14-55 
 1-86 
 14-50 
 7-79 
 38 19 
 
 21-35 
 
 8-51 
 
 14-07 
 2-46 
 13-46 
 5-52 
 26-11 
 
 30-80 
 
 6-26 
 14-27 
 
 2-88 
 12-68 
 5-24 
 20-74 
 
 27-11 
 
 4-99 
 14-40 
 3-88 
 15-41 
 5-7) 
 29-31 
 
 25-98 
 
 5-5 
 127 
 2-9 
 13-0 
 7'9 
 21-7 
 1-9 
 34*6 
 
 5-0 
 13-8 
 41 
 67-3 
 
 i" 
 
 92 
 
 f>-7 
 13-9 
 36 
 14-9 
 
 Ul-0 
 
 97 
 1-2 
 
 Fat 
 
 N trofrenous matter (gluten, &c.) . 
 
 
 Sugar ..... . . 
 
 Cellulose . 
 
 Resinous and odoriferous matter . 
 
 101-59 
 2-23 
 
 98*94 
 207 
 
 98-28 
 1-95 
 
 9968 
 2-37 
 
 100-0 
 
 104 1 
 
 100-0 
 
 
 Kekule's determination of the nitrogenous matter is probably too high. The 13*0 
 per cent, nitrogenous matter found by Poggiale was made up of 5'6 soluble matter 
 (albumin), 3'9 insoluble, but capable of assimilation, and 3'5 insoluble and incapable 
 of assimilation. Poggiale isolated the cellulose by rendering the starch soluble with 
 diastase ; he finds that the usual process of determination by the successive use of acids 
 and alkalis, always gives the amount of cellulose too low, part of it being converted 
 by those reagents into sugar and dextrin. 
 
 Bran, though rich in nitrogen, appears to possess but little nutritive power. Animals 
 fed upon it quickly lose flesh (Poggiale). It contains a nitrogenous principle called 
 cereal in, analogous to diastase, and perhaps identical therewith, which possesses the 
 power of quickly converting starch into dextrin and sugar. Mouries found that 130 pts. 
 of wheaten bread containing bran easily diffused through 520 parts of water when tri- 
 turated therewith, and yielded 59'35 pts. of soluble and 6975 pts. of insoluble matter, 
 whereas the same quantity of bread not containing bran, was converted by trituration 
 with water into a semisolid mass, and yielded only 9'03 per cent, soluble matter to 
 120'25 insoluble. This action of the bran on the flour commences in the kneading 
 and baking, but is completed only in the stomach. (See BREAD.) 
 
 Bran is used by calico-printers in the clearing process, for removing the colouring 
 matters adhering to the non-mordanted parts of the maddered goods, as well as the dun 
 matters which cloud the mordanted portions. (See Ure's Dictionary of Arts, Manu- 
 factures, and Mines, i. 383.) 
 
 BRAUCKITE. C ! 'H 16 . A fossil hydrocarbon from the lignite of Mount Vaso in 
 Tuscany. It is colourless and translucent, like Scheererite ; melts at 75 C. but does 
 not crystallise on cooling. It dissolves in alcohol. Specific gravity = TOO. (Savi, 
 Leonhard and Bronn's Jahrbuch, 1842, p. 459.) 
 
 BZIAHTJDZSXTX:. See CLINTONITE. 
 
 BS-AIMDY. This well known liquor is the spirit distilled from wine, and forms 
 an extensive article of trade in the south of Europe. It is generally manufactured 
 from white or pale-red wines, but often from inferior articles, such as the refuse wine 
 and the marcs of the wine-press. Distillation of the wines is the only process neces- 
 sary for procuring brandy : hence the richer the wine in alcohol, the greater will be 
 the yield of brandy. Many circumstances, however, independent of the manufacture, in- 
 fluence the quality of the product. Thus, white wines do not always afford more alcohol 
 than the red, but they yield a spirit of finer quality, because they contain more of the 
 essential oil of grapes. Wines which have a certain taste of the soil, communicate it 
 to the brandy derived from them by distillation ; thus, the wines of Selleul in Dauphin6 
 give a brandy which has the odour and taste of the Florentine iris ; those of St. Pierre 
 in Vivarais, give a spirit which smells of the violet, and so of many other varieties. 
 
 Eeal Cognac is obtained from the distillation of choice wines, every attention being 
 paid to the proper degree of cleanliness in the various utensils employed. In the im- 
 proved form of still, a very superior article is obtained from inferior wines, but the 
 small proportion of essential oils in such wines divests the brandy of that aromatic 
 
BRASS BRASSICA. 653 
 
 flavoiir which belongs to the better sorts of wine, and is communicated to the brandies 
 procured from them. An inferior brandy called cau-dc-vie de marcs is obtained by dis- 
 tilling the dark red wines of Portugal, Spain, and other wine-growing countries, also 
 the lees deposited by wine in keeping, the marc or refuse of the grapes from the wine- 
 press, the scrapings of wine-casks, &c. 
 
 Brandy, as sold in France, is generally of two strengths, designated as a prcuve de 
 Hollande, and a preuve d'huile, the former varying from 18 to 20 Beaume. The 
 stronger liquors are valued according to the quantity of eau de vie a preuve de Hollande 
 that a given quantity will furnish on the addition of the proper quantity of water. 
 These strengths are usually twelve, viz. of five-six, four-Jive, three-four, two-three, 
 three-five, four-seven, five-nine, six-eleven, three-six, three-seven, three-eight, and three- 
 nine, but the last is rarely made. The meaning of these strengths is as follows : If 
 a spirit be five-six, 5 pts. of the spirit will give a liquor a preuve de Hollande, when 
 added to six measures of water. The spirit five-six has a specific gravity of 0*9237 or 
 22 Bm. ; but all the other strengths are variable, on account of the uncertainty of 
 the strength of the spirit a prcuve de Holland. 
 
 The following is an average of the yield of brandy which some wines afford by dis- 
 tillation : 
 
 1000 litres of wine of St. Gilles, in the environs of Montpellier, afford 
 
 of three-six brandy 150 litres 
 
 of good wine of calcareous soils 140 
 
 of wines of fertile soils near Montpellier . . . 100 
 
 of wines of soils producing much grapes . . . 100 
 
 Wines of the countries nearest the Mediterranean furnish the largest proportion of 
 brandy, which diminishes as the grapes grow in more northern countries. 
 
 British brandy is an artificial product fabricated by the rectifying distiller. The 
 following receipt is given by Ure : " Dilute the pure alcohol to the proof pitch, and 
 add to every hundred pounds weight of it from half a pound to a pound of argol crude 
 tartar dissolved in water, some bruised French plums, and a quart of good cognac. 
 Distil this mixture over a gentle fire in an alembic provided with an agitator. The 
 addition of brandy and argol introduces cenanthic ether, and if a little acetic ether be 
 added to the distillate, the whole imparts the peculiar taste of genuine Cognac brandy. 
 Colour with burnt sugar if necessary, and add a little tannic acid to impart astrin- 
 gency." (See Ure's Dictionary of Arts, Manufactures, and Mines, i. 389 ; also Mzis- 
 pratfs Chemistry, i. 103.) 
 
 BRASS. An alloy of copper and zinc. (See COPPER ; also Ure's Dictionary of 
 Arts, Manufactures, and Mines, i. 399.) 
 
 BRASSICA. A genus of cruciferous plants, including some of the most impor- 
 tant fodder plants and culinary vegetables, viz. the cabbage, rape, and turnip. 
 
 1. Brassica ohracca. Cabbage. Of this species, many varieties are cultivated for 
 their leaves, c . g. the common red or white cabbage (Br. ol. capitatii], the Savoy cabbage 
 (Br. ol. bidlata), curled kale (Br. ol. acephahi), &c. The turnip-stemmed cabbage, or 
 kohl-rabi (Br. ol. caulorapa or napobrassica), is much cultivated in France and 
 Germany for its fleshy turnip-like stem or bulb, which makes an excellent vegetable 
 dish. Cauliflower and broccoli are also varieties of Brassica oleracea. 
 
 Fresh white cabbage-leaves contain 0-2 per cent, nitrogen ; the dried leaves 3'7 per 
 cent. (Boussingault, Ann. Ch. Phys. [2] Ixviii. 337). Table A exhibits the compo- 
 sition of cabb'age leaves as determined by Anderson (Chem. Centr. 1856, p. 232). 
 a. Of the young plant before the heart-leaves are formed, b. The outer leaves of 
 perfectly ripe cabbage, c. The heart-leaves of the same. 
 
 TABLE A. Composition of Cabbage-leaves. 
 
 a b c 
 
 Albuminous substances . . . 2*1 1*6 0'9 
 
 "Woody fibre, gum, and sugar . . 4 -5 5'0 4'1 
 
 Ash 1-6 2-2 0-6 
 
 Water 91-8 91-1 94-4 
 
 According to Sprengel (J. techn. Chem. xiii. 485), white cabbage contains, in the 
 air-dried state, 52'5 per cent, water, 19*3 percent, matter soluble in potash-ley, 25*6 per 
 cent, woody fibre, besides wax, chlorophyll, &c. The ash of cabbage has been analysed 
 by Way and Ogston (Journ. Koy. Agr. Soc. vii. [2] 593; xi. [2] 512), by Sprengel 
 and by Stammer (Ann. Ch. Pharm. Ixx. 294). 
 
 The fleshy stem or bulb of the kohl-rabi contains, according to Sprengel (loc. tit.) 
 " 91 per cent, water, the leaves 86 per cent, water. 100 pts. of the dried substance con- 
 tain 41-4 pts. soluble in water, 38'2 soluble in potash-ley, 18'5 woody fibre, besides 
 
654 
 
 BRASSICA, 
 
 wax, fat, &c. The ash of the cornis and leaves has been analysed by Sprengel, and 
 by Way and Ogston (loc. tit.) 
 
 The ashes of the heart of cauliflower (Br. ol. var. botrytis cauliflord), and of the root 
 and leaves of broccoli (Br. ol. var. botrytis asparago'idcs) have been analysed by 
 Th. Eichardson, Ann. Ch. Pharm. Ivii. ; Anhang zum dritten Heft). 
 
 TABLE B. Ash of different Varieties of Brassica oleracea. 
 
 
 Way anc 
 CoruC 
 Leaves. 
 
 O^ston. 
 Mae 
 Stalk. 
 
 Sprengel. 
 White 
 
 Stammer. 
 Cabbage 
 
 Way anc 
 Bulbs. 
 
 1 Ogston. 
 Kohl. 
 Leaves. 
 
 Spre 
 cM 
 Bulbs. 
 
 ngel. 
 Leaves. 
 
 R 
 
 Canti. 
 
 Jlower 
 Hearts. 
 
 chardso 
 Bra 
 Root. 
 
 n. 
 *coli 
 Leaves. 
 
 Ash in 100 pts. of fresh plant . 
 
 0-7 
 
 1-2 
 
 _ 
 
 
 
 _ 
 
 
 
 0-95 
 
 2-80 
 
 0-71 
 
 roi 
 
 1-70 
 
 ,, ,, air-dried plant 
 
 __. 
 
 -_ 
 
 
 
 
 
 H. 
 
 . 
 
 
 
 
 ,, plants dried ) 
 at 100 C j 
 
 10-0 
 
 
 
 7-5:. 
 
 1T62 
 
 7-05 
 
 12-90 
 
 8-09 
 
 18-54 
 
 
 
 
 Composition of ash in 100 pts. : 
 
 
 
 
 
 
 
 
 
 
 
 
 Potash (anhydrous) .... 
 Soda .... 
 
 40-9 
 2-4 
 
 40-9 
 4-0 
 
 313 
 
 12-0 
 
 48-3 
 
 37-6 
 133 
 
 17-8 
 8-1 
 
 36-3 
 
 2-8 
 
 9-3 
 
 47-16 
 
 3'l-39 
 14 79 
 
 22 10 
 7 65 
 
 Lime . . 
 
 15-0 
 
 106 
 
 23' 1 
 
 1-2-6 
 
 ll'l 
 
 34-2 
 
 10'2 
 
 30-3 
 
 4-70 
 
 2-96 
 
 26'4-l 
 
 Magnesia ......* 
 
 2-4 
 
 3-8 
 
 0-3 
 
 3-7 
 
 4-0 
 
 32 
 
 2'3 
 
 3-6 
 
 3-93 
 
 2-38 
 
 3-43 
 
 Alumina 
 
 
 
 0-2 
 
 
 0-5 
 
 0'2 
 
 
 
 
 
 
 Ferric oxide 
 
 9-8 
 
 0-4 
 
 O'l 
 
 1-8 
 
 0-5 
 
 0-9 
 
 0-4 
 
 5-5 
 
 
 
 
 Su phuric anhydride . . . 
 Silicic ... 
 
 7-3 
 
 10-6 
 
 11-1 
 1-0 
 
 12-7 
 2-8 
 
 8-3 
 
 0-4 
 
 12-6 
 6-7 
 
 14-0 
 7-1 
 
 11'4 
 0-8 
 
 10-6 
 9-6 
 
 11-16 
 1-92 
 
 1035 
 009 
 
 IG'IO 
 1 83 
 
 Carbonic ... 
 
 16-7 
 
 6-3 
 
 __ 
 
 __ 
 
 
 _ 
 
 10-2 
 
 9'0 
 
 
 
 
 Phosphoric ... 
 
 12-5 
 
 19-6 
 
 10-4 
 
 169 
 
 5^8 
 
 5-4 
 
 13-5 
 
 94 
 
 25-84 
 
 24-83 
 
 16-62 
 
 Calcic, magnesic, and ferric 
 
 
 
 
 
 
 
 
 
 
 
 
 phosphates ..... 
 
 _ 
 
 . p 
 
 __ 
 
 
 
 
 < ___ 
 
 __ 
 
 
 3-67 
 
 2-12 
 
 6-21 
 
 Chloride of potassium . . . 
 
 _ 
 
 
 
 
 
 9 3 
 
 
 
 
 
 
 
 6-0 
 
 
 622 
 
 
 sodium .... 
 
 trace 
 
 2-1 
 
 G-0 
 
 
 
 6'1 
 
 78 
 
 ii'9 
 
 6-7 
 
 2^78 
 
 trace 
 
 
 
 2. Brassica Napus. Winter rape, Coleseed, a.nd.Br.campestrisvar. oleifera, 
 Summer rape, Colzat or Colza, are cultivated chiefly for their seeds, which yield 
 a large quantity of oil, and for the succulent food which their thick fleshy stems and 
 leaves supply to sheep when other fodder is scarce. The cake which remains after the 
 oil has been pressed from the seed, is used on the continent as food for cows and pigs, 
 and also as a manure, for which purpose large quantities of it are imported into Eng- 
 land. Colza or summer rape yields the largest quantity of oil, but winter rape is said 
 to be hardier, and is therefore more generally cultivated in this country. Way (Journ. 
 Eoy. Agr. Soc. x. part 2) found, in 100 pts. of the dry seed of dwarf rape, 4-2 percent, 
 nitrogen, 3 7 '8 fat, 3 -3 ash, and 6 '5 water. Of the ash of the seed and straw of rape, 
 numerous analyses are given in Liebig and Kopp's Jahresbericht fur Chemie for 1849, 
 tables D and E to page 656. From these we extract the following : 
 
 TABLE C. Ash of the Seed and Straw of Brassica Napus. 
 
 
 Liebig, 
 Seed. 
 
 Erdmann, 
 Seed. 
 
 Rammelsberg, 
 Seed. 
 
 We 
 Seed. 
 
 t>er, 
 Straw. 
 
 Ash in 100 pts. of air-dried plant 
 plant dried at 100 C. . 
 
 5 19 
 
 4-03 
 
 4-44 
 
 2-39 
 
 3-41 
 
 Composition of ash in 100 pts. : 
 
 
 
 
 
 
 Potash . ... 
 
 22-5 
 
 22'7 
 
 25-7 
 
 22-9 
 
 24-9 
 
 
 0-2 
 
 
 
 
 6-5 
 
 
 11*8 
 
 I4'6 
 
 13-2 
 
 17-3 
 
 32'8 
 
 
 11-1 
 
 12 
 
 11-6 
 
 15-5 
 
 54 
 
 Ferric oxide 
 
 1'7 
 
 0-() 
 
 O-G 
 
 0-7 
 
 1*7 
 
 
 6-7 
 6'0 
 
 05 
 11 
 
 5 
 
 ri 
 
 0-5 
 2-0 
 
 1?2 
 4*1 
 
 
 Carbonic " ... 
 
 
 
 
 
 147 
 
 
 39-1 
 
 47-0 
 
 47*0 
 
 41-6 
 
 4*5 
 
 
 
 
 
 
 2-1 
 
 sodium 
 
 0-8 
 
 
 
 
 
 
 
 
 3. Brassica Bapa, the common white turnip, and Br. campestris var. rutabaga, 
 or napobrassica, the swede turnip. The ashes of these plants have been examined 
 by T. J. Herapath (Chem. Soc. Qu. J. ii. 14), Eggers (Jahresber. f. Chem. 1849, 
 p. 656); Baer (ibid. 1851, p. 710); Stammer (Ann, Ch. Pharm. Ixx. 295); and Way 
 and Ogston (loc. cit.). 
 
BRASSIC ACID BRAZIL WOOD. 
 
 655 
 
 TABLE D. Com 
 
 of Turnip-ash. 
 
 
 Hera 
 
 ^Snede 
 Bulbs 
 
 path. 
 
 1 , 
 White 
 
 Bulbs. 
 
 Way and Ogston. 
 
 B 
 
 ^- ' 
 
 Seed. 
 
 ler. 
 
 . 
 
 Straw. 
 
 Stammer. 
 Bulbs. 
 
 Eggers. 
 
 Oil- 
 cake. 
 
 f Siv 
 Bulbs. 
 
 tile 
 Leaves. 
 
 Dale'* 
 Bulbs. 
 
 Hybrid 
 Leaves. 
 
 Green 
 mil 
 Bulbs. 
 
 popped 
 Leaves. 
 
 Seed. 
 
 Ash in 100 pts. of fresh 
 plant 
 
 1-23 
 
 0'65 
 
 075 
 
 1 97 
 
 1-09 
 
 1-19 
 
 059 
 
 1-82 
 
 3-67 
 
 
 
 0-46 
 
 5-70 
 
 Ash in 100 pts. of air- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 dried plant .... 
 
 _ 
 
 
 
 __ 
 
 
 
 __ 
 
 
 
 
 
 _ 
 
 _ 
 
 4-58 
 
 4-41 
 
 
 
 Ash in 100 pts. of plant 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 dried at 100 C. . . 
 
 
 
 
 
 6-00 
 
 16-40 
 
 8-41 
 
 10-80 
 
 7-40 
 
 15-20 
 
 3-98 
 
 
 
 
 
 7'00 
 
 6-13 
 
 Composition of the ash 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 in 100 pts. : 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 62-6 
 
 47-9 
 
 23-7 
 
 11 16 
 
 36-9 
 
 13-5 
 
 48-5 
 
 12-7 
 
 21-9 
 
 16-1 
 
 16'5 
 
 46-5 
 
 21-9 
 
 Soda 
 
 trace 
 
 
 14-7 
 
 12-4 
 
 8-0 
 
 46 
 
 
 
 1-2 
 
 1-1 
 
 1-3 
 
 
 
 
 6-9 
 
 14'7 
 
 
 28-5 
 
 6-5 
 
 3-i-l 
 
 6-7 
 
 28-7 
 
 17'4 
 
 11-3 
 
 25-4 
 
 13 1 
 
 8-6 
 
 
 2'5 
 
 2-4 
 
 3-3 
 
 2-6 
 
 2-5 
 
 1-7 
 
 2-3 
 
 
 8-7 
 
 10-4 
 
 11-0 
 
 1-6 
 
 14-7 
 
 Aluinina, . 
 
 trare 
 
 
 
 
 
 
 
 
 
 05 
 
 02 
 
 
 
 Ferric oxide .... 
 
 0-25 
 
 trace 
 
 0-5 
 
 3~0 
 
 o-i 
 
 0-6 
 
 0-6 
 
 0-8 
 
 1-9 
 
 1-0 
 
 1-2 
 
 
 45 
 
 Sulphuric anhydride . 
 Silicic 
 
 42 
 OM 
 
 2'6 
 1 2 
 
 16-1 
 27 
 
 10-4 
 80 
 
 1J-7 
 
 6-7 
 1 2 
 
 12-8 
 09 
 
 7-8 
 2-0 
 
 7-1 
 
 0-7 
 
 7-9 
 0-9 
 
 5-5 
 3-4 
 
 9-9 
 1 
 
 1-6 
 13-1$ 
 
 Carbonic 
 
 * 
 
 
 
 10-7 
 
 62 
 
 12-6 
 
 13-8 
 
 14-8 
 
 14-0 
 
 0-8 
 
 6-9 
 
 27-6 
 
 
 2M 
 
 Phosphoric 
 
 15-9 
 
 16-6 
 
 9-3 
 
 4-9 
 
 8-8 
 
 4*6 
 
 7-6 
 
 
 40-1 
 
 34-0 
 
 4-0 
 
 15-5f 
 
 32-7 
 
 Chloride of potassium 
 sodium . 
 
 jr. 
 
 14-6 
 
 7 T 1 
 
 12'4 
 
 10-0 
 
 18-0 
 
 5^4 
 
 15'5 
 107 
 
 
 
 6-8 
 
 3-2 
 
 10-6 
 
 0-2 
 0-5 
 
 
 
 
 
 
 
 
 | 
 
 
 
 
 
 
 BRASSIC ACID. Colza oil is, according to Websky (J. pr. Chem. Iviii. 449), 
 a mixture of two glycerides, which yield by saponification, brassic acid, which is 
 solid at ordinary temperatures, melts between 32 and 33 C., and crystallises from 
 alcohol in long needles ; and another acid, which is liquid at ordinary temperatures 
 and resembles oleic acid. The two acids are easily separable by means of their lead- 
 salts, the salt of the oily acid being soluble in ether, while brassate of lead is insoluble. 
 Websky assigns to brassic acid the formula C"H0*. Stadeler (Ann. Ch. Pharm. 
 Ixxxvii. 133) proposes C U H0\ or C^H^O 2 , which agrees quite as well with the 
 analyses, and is the same as that of erucic acid, extracted by Darby from oil of 
 mustard. Brassate of sodium gives by analysis 8 '5 per cent, soda; the formula 
 C t>2 H 41 Na0 2 requires 8 '6 per cent. 
 
 13RAUNZTE. Native sesquioxide of manganese. See MANGANESE, 
 
 BRAUWSTEIBT. The German name of peroxide of manganese. 
 
 BRAYERA AWTHEIMZSTTICA (Kunth), orHagenia abyssinica (Lamarck). 
 The flowers of this plant, called Kusso or Kosso, contain,' according to Viale and 
 Latini (Correspond. Scient. in Eoma, Nov. 1852), a peculiar acid, hagenio add, in 
 combination with ammonia. 
 
 Harms (Arch. Pharm. [2] Ixxxviii. 165) found in 100 pts. of the ash of kusso, 
 after deducting sand and charcoal : 
 
 CO 2 
 13-58 
 
 A1 4 3 
 1-97 
 
 SO 3 
 1-90 
 
 Mg 2 
 6-43 
 
 P 2 5 
 1443 
 
 Ca 2 
 13-37 
 
 SiO 2 
 3-14 
 
 Na 2 
 13-41 
 
 Fe 4 3 .P 2 5 
 5-50 
 
 K 2 O 
 
 18-89 
 
 NaCl 
 7-38 
 
 Mn s 2 
 trace 
 
 BRAZIXi WOOD. The tree which yields this wood, the Casalpina crispa, grows 
 in Brazil, and also in the Isle of France, Japan, and elsewhere. There are several 
 varieties, distinguished by the names of the localities from which they are obtained, as 
 Pernambuco, Lima, Santa Martha, Sapan (from Japan), &c. Pernambuco wood 
 and Lima wood contain the largest amount of colouring matter ; viz. about 2'7 per 
 cent. ; Sapan wood, only about 1*5 per cent. Peach or Nicaragua wood, sometimes 
 called Santa Martha wood, is still inferior in point of quantity, but is preferred for 
 some purposes. 
 
 Brazil wood is heavier than water, very hard, and susceptible of a good polish. 
 Its colour is pale when newly cut, but becomes deeper by exposure to the air. The 
 heaviest specimens generally yield the best colour. It has a sweetish taste when 
 chewed, and is distinguished from red Sanders or sandal wood by giving out its colour 
 to water, which sandal wood does not. The colouring matter may also be extracted 
 by alcohol or ammonia, and with greater facility than by water. The spirituous 
 tinctxire, according to Dufay, stains warm marble of a purplish red, which, on in- 
 creasing the heat, becomes violet ; and, if the stained marble be covered with wax and 
 
 * In the calculation of Herapath's analysis, the carbonic acid is deducted. 
 
 f Mixed with sand. t And 1-5 basic ferric phosphate. 
 
656 BREAD. 
 
 considerably heated, it changes through all the shades of brown, and at last becomes 
 fixed of a chocolate colour. 
 
 According to Chevreul (Ann. Chim. Ixvi. 226) the red colouring matter of Brazil 
 wood, to which he gives the name Brazilin, exists ready formed in the wood, and is 
 simply dissolved out by water or other solvents; but according to Preisser ( Ann. 
 Ch. Pharm Hi. 369), the red colouring matter, Brazilein, consisting of C 18 H 14 7 , is 
 formed by oxidation from a colourless principle, Brazilin, C 18 H H 6 , contained in the 
 wood, so that Preisser's brazilein is the same as Chevreul's brazilin. 
 
 Preisser prepares brazilin by agitating a concentrated alcoholic extract of the wood 
 with hydrate of lead, decomposing the resulting salt with sulphydric acid, filtering and 
 evaporating the colourless liquid, which affords small, acicular, colourless crystals of 
 brazilin, C 18 H 14 8 , whose aqueous solution slowly turns yellow on exposure to the air, 
 and at the margin brilliant red. This change takes place more quickly on boiling the 
 liquid, which then, on cooling, deposits brilliant red needles of brazilein, C I8 H I4 ? . 
 Chevreul originally obtained the red crystals by agitating the aqueous extract of the 
 wood with oxide of lead, evaporating the filtrate to dryness, and digesting the residue 
 in alcohol. The solution thus obtained yielded the red crystals by spontaneous evapo- 
 ration. Possibly the colourless brazilin was oxidised to brazilein during the process. 
 At all events, Preisser's view is in accordance with the fact that Brazil wood becomes 
 darker in colour by exposure to the air. 
 
 Brazilin is soluble in alcohol and ether. Hydrochloric acid, with access of air, 
 colours it bright red. Sulphuric acid dissolves it with yellow colour, which soon 
 changes to black. Nitric acid first reddens it, then gives off red fumes, and converts 
 it into oxalic acid. Potash and soda, in contact with the air, also turn it red ; am- 
 monia, dark red purple. The aqueous solution forms a yellowish precipitate with 
 acetate of lead, and reduces gold and silver from their solutions. Chromic acid, or 
 pulverised acid chromate of potassium, introduced into the aqueous solution, produces 
 brisk effervescence, arising from the escape of formic acid, and gradually precipitates 
 a dark crimson lake, consisting of a compound of hydrate of chromium with brazileiu. 
 (Preisser.) 
 
 Brazilein is soluble in water, alcohol, and ether, forming red solutions, which are 
 decolorised by sulphydric acid, are coloured purple by alkalis, and form purple pre- 
 cipitates with lead and tin salts, and a red precipitate with alum. 
 
 These precipitates, obtained with an aqueous decoction of Brazil wood, are exten- 
 sively used for dyeing and for staining paper for walls. The solubility of the colouring 
 matter of Brazil wood, and its strong affinity for mordants, give it a very extensive 
 range of application both in dyeing and in calico-printing. (See Muspratffs Chemistry, 
 i. 573, and Ure's Dictionary of Arts, Manufactures, and Mines, i. 397.) 
 
 BREAD. Bread consists of the flour of wheat or other cereal grain, kneaded 
 with water into a paste or dough, which is rendered porous by the interpenetration of 
 carbonic acid gas, either generated within the mass of the dough by fermentation, or 
 forced into it by mechanical means. The dough having thus acquired the proper 
 degree of porosity, is exposed to the heat of an oven, whereby the enclosed gas is 
 further expanded, its escape being prevented by the simultaneous formation of the 
 crust. The crumb of the bread thus produced is a soft porous mass, of swollen but 
 otherwise unaltered starch, mixed with vegetable fibrin ; in the crust, the starch is 
 mainly converted into dextrin and empyreumatic products. 
 
 It is the rising of the dough, produced by the carbonic acid, which gives to well 
 made bread its peculiar lightness, and distinguishes it from the close, heavy cake, pro- 
 duced by merely mixing flour with water and baking it. The usual method of gene- 
 rating the carbonic acid is by fermentation, and the manner in which this process is 
 conducted has great influence on the quality of the bread ; as, if it be not carried far 
 enough, the dough will not rise sufficiently, and if allowed to go too far, it gives rise 
 to the formation of acid and other objectionable products. To facilitate the under- 
 standing of it, we must give some account of the composition of flour. 
 
 The flour of all cereal grains consists of an azotised portion, chiefly vegetable fibrin ; 
 a non-azotised portion, chiefly starch, with variable quantities of dextrin and sugar; 
 and inorganic salts, chiefly phosphates. 
 
 If moistened wheat flour be kneaded into a stiff paste, and well washed with water, 
 a milky liquid runs off, and a viscid elastic solid, called gluten, is left behind. The 
 milky liquid, if left to stand, deposits a quantity of starch mixed with minute par- 
 ticles of gluten, and the clear liquid filtered from the deposit, leaves on evaporation, a 
 quantity of extractive matter, consisting of vegetable albumin, dextrin, glucose, 
 or grape-sugar, possibly also gum, and other similar proximate principles, besides 
 soluble inorganic salts. The gluten, which is essentially the flesh-forming constituent 
 of the flour, consists of vegetable fibrin, held together by a very tenacious nitrogenous 
 substance, called gJutin or gliadin, which may be extracted by alcohol ; it also con- 
 
BREAD. 657 
 
 tains small quantities of fat, and fine particles of bran mechanically mixed. It is the 
 gliadin which gives to the nitrogenous portion of wheat-flour its peculiar adhesiveness, 
 and causes the dough prepared with it to rise into a spongy mass when penetrated by 
 gases. Other cereal grains, oats and rye for example, though rich in vegetable fibrin, 
 contain scarcely any gliadin, and consequently the dough prepared from them possesses 
 but little tenacity. This is the chief cause of the great superiority of wheat, over all 
 other cereals, for the preparation of bread. 
 
 When flour in the moist state is exposed to the air, the nitrogenous matter quickly 
 passes into a peculiar state of decomposition, in which it is capable of acting as a fer- 
 ment, converting the starch into dextrin and glucose, and the glucose into alcohol and 
 carbonic acid (see FERMENTATION). Hence a portion of dough which has been left till 
 it undergoes partial decomposition, and in which state it is called leaven, is capable 
 of inducing the so-called panary, but really alcoholic fermentation, in a much larger 
 quantity of dough, when well kneaded with it. "A little leaven leaveneti. the whole 
 lump." This method of bread-making has been practised from the oldest times, and 
 is still the only one in use for the coarser kinds of bread, such as the Schwarzbrot, or 
 black bread of Germany ; but for the finer sorts, beer-yeast is now used as a substitute, 
 or rather as a partial substitute of leaven. The process generally adopted in this 
 country is as follows : A certain quantity of flour is mixed with yeast, salt, and tepid 
 water. This constitutes the "sponge," which is covered up and set aside in a warm 
 place, to undergo fermentation. In the course of an hour or so, the mass swells up 
 considerably from the generation of carbonic acid, large bubbles of which rise to the 
 surface and burst. With each successive burst, a sudden falling of the sponge takes 
 place, followed by a gradual rising, and these alternate actions would, if allowed, con- 
 tinue for many hours. Various other modes of making an active sponge are employed, 
 particularly by the use of potatoes. When the sponge, no matter how formed, is in an 
 efficient condition, the baker mixes up with it fresh portions of flour, salt, and water, the 
 quantities so added forming the greater part of the dough. The whole is then subjected 
 to a thorough kneading with the hands, or sometimes with the feet, so that the ferment- 
 ing dough may permeate and affect the entire substance, and thus cause an equable 
 liberation of carbonic acid in every particle. The dough is set aside for a few hours, 
 during which the fermentation proceeds, then kneaded a second time, and weighed out 
 into loaves, which are allowed to continue fermenting till they have doubled their 
 original bulk. They are then baked in the oven, within which they undergo a further 
 increase of size, due chiefly to the expansion by heat of the confined gases : for the 
 heat of the oven quickly arrests the fermentation. 
 
 In Paris, where bread-making has been brought to a high degree of perfection, the 
 fermentation is produced chiefly by the gluten of the dough, yeast being used merely 
 to facilitate the action. A lump of dough remaining from the last batch of bread, and 
 consisting of 8 Ibs. flour and 4 Ibs. water, is left to itself for ten hours : in this state 
 it is called fresh leaven (levain de chef]. By kneading this with another quantity 
 of 8 Ibs. flour and 4 Ibs. water, the once-revived leaven (levain de premiere') is 
 obtained. After another interval of eight hours, 16 Ibs. of flour and 8 Ibs. water are 
 added, forming the twice-revived leaven (levain de seconde) ; and after three hours 
 more, 100 Ibs. flour and 52 Ibs. water containing i to ilb. beer-yeast are added, form- 
 ing the finished leaven (levain de tout point}. The 200 Ibs. leaven thus obtained 
 are mixed, after two hours, with 132 Ibs. flour and 68 Ibs. water, containing ^ Ib. of 
 yeast in suspension and 2 Ibs. common salt dissolved. This quantity of dough serves 
 for five or six bakings. For the first baking, half the dough (200 Ibs.) is made 
 into loaves of the required size and form, which are exposed for a while in shallow 
 baskets, to a temperature of 25 C. (77 F.), and then transferred to the oven. The 
 bread thus obtained has a sourish taste and dark colour. The remaining half of the 
 dough is again mixed with 132 Ibs. flour, 70 Ibs. water, ilb. yeast, and the requisite 
 quantity of salt; the half of this quantity of dough is then formed into loaves, left to 
 ferment, and baked. The same^ operations are repeated three times, one-half of the 
 dough being each time mixed with 130 Ibs. flour, lilb. yeast, and the proper quantity 
 of water and salt. The last stage yields the finest and whitest bread. 
 
 In the normal process of bread-making, the carbonic acid, whose evolution gives 
 lightness to the bread, is derived principally, if not wholly, from the fermentation of 
 the sugar of the flour, induced by the action of metamorphic gluten. But flour, as 
 already observed, contains other nitrogenised substances than gluten, and other non- 
 nitrogenised substances than sugar. Now these nitrogenous substances, the albumin, 
 for example, readily undergo transformation, and then act as ferments, not only upon 
 sugar and dextrin, but also upon starch, transforming it into dextrin and sugar, and 
 sometimes also into lactic acid. This is the process which takes place in the germination 
 of grain, in malting for example (p. 328), by the action of the albumin in the peculiar 
 state called diastase. Now when wheat has been too much exposed to damp during 
 
6o8 BREAD. 
 
 harvesting, or has sprouted from any subsequent cause, or when the flour even of well- 
 harvested wheat is exposed to heat and moisture, the albumin passes into this peculiar 
 state, and the flour becomes incapable of yielding good bread, because, during the 
 process of bread-making, the conversion of starch into dextrin and sugar, which always 
 occurs to a slight extent, then takes place in an exaggerated degree. Bread made 
 from such flour, is sticky, saccharine, and soddened, never light and porous. The 
 conversion of the starch into dextrin and sugar likewise renders the bread darker in 
 colour. In fact, the brown colour of wheaten bread made from flour containing fine 
 bran, is due, not to admixture of particles of bran, but in great part at least to a con- 
 version of the starch into dextrin and sugar by the action of the altered albuminous 
 matter in the bran. According to Mege-Mouries, bran contains a peculiar nitrogenous 
 body called cercalin, which is specially active in inducing this conversion : it appears, 
 however, to be identical or nearly identical, with ordinary diastase. Be this as it 
 may, it is certain that the finest wheat flour obtained from the central portion of the 
 grain, which contains but little nitrogenous matter, has very little tendency to undergo 
 the change under consideration ; but coarse flour obtained from the exterior of the 
 grain, is rich in azotised substances, and more ready to undergo the glucosic deteriora- 
 tion. In white bread of good quality, the starch has undergone very little alteration. 
 A small portion of it is rendered soluble in water, but the greater number of the 
 granules are simply swollen, not burst, and may be washed out of the bread, collected, 
 and weighed. Vogel gives the following analysis of a wheat-bread loaf: sugar, 3*6 
 percent; altered starch, 18'0; unaltered starch, 53 - 5 ; gluten, with some starch, 
 20-7 = 95-8. 
 
 The injurious action of diastase, &c. on starch in the process of bread-making, may 
 be prevented by the addition of certain mineral substances. Alum has long been 
 employed for this purpose by bakers, and it certainly has the effect of rendering 
 available for bread-making many qualities of flour, which must otherwise be wasted. 
 Dr. d ling says (Journal of the Society of Arts, April 9, 1858) : "If we mix a solution 
 of starch with infusion of malt, in the course of a few minutes only, the starch can no 
 longer be detected, being completely converted into dextrin and sugar, but the addition 
 of a very small quantity of alum prevents altogether or greatly retards the trans- 
 formation. The action of diastase on undissolved starch is very gradual, but here also 
 the interference of the alum is easily recognisable. Bread made with infusion of bran 
 or infusion of malt, is very sweet, sodden, brown-coloured, and so sticky as almost to 
 bind the jaws together during mastication. But the addition of alum to the dough 
 causes the loaves to be white, dry, elastic, crumbly, and unobjectionable, both as to 
 taste and appearance. I have found that flour which is of itself so glucogenic as to 
 yield bread undistinguishable from that made with infusion of malt, could, by the ad- 
 dition of alum, be made to furnish a white, dry, eatable loaf." 
 
 Alum is also said to prevent bread from turning sour and mouldy. The sourness 
 often observed in bread of inferior quality, arises from the conversion of part of the 
 starch into lactic acid. Now as alum prevents the transformation of starch, it may be 
 expected also to interfere with the production of lactic acid. 
 
 Considerable discussion has taken place as to the probable effects of the habitual 
 use of alumed bread on the digestive functions, some medical men asserting that alum, 
 unless taken in much larger quantity than is likely to occur in bread, is quite harmless, 
 while others attribute to it the most injurious effects. In this, as in many cases, the 
 truth probably lies in the middle. Many of the statements which have been put forth 
 on this, as on other questions relating to the adulteration of food, are doubtless grossly 
 exaggerated ; nevertheless, it would be unsafe to assert that the use of alum is quite 
 free from objection. Dr. Dauglish, in a paper to which we shall have again to refer, 
 says: "Its effect on the system is that of a topical astringent on the surface of the 
 alimentary canal, producing constipation, and deranging the process of absorption. 
 But its action in neutralising the efficacy of the digestive solvents, is by far the most 
 important and unquestionable. The very purpose for which it is used by the baker, 
 is the prevention of those early stages of solution which spoil the colour and lightness 
 of the bread whilst it is being prepared, and which it does most effectually ; but it 
 does more than needed : for whilst it prevents solution at a time that is not desirable, 
 it also continues its effects when taken into the stomach, and the consequence is, that 
 a large portion of the gluten and other valuable constituents of the flour, are never 
 properly dissolved, but pass through the alimentary canal without affording any nourish- 
 ment whatever." 
 
 Another objection made against the use of alum, viz. that it has the power of causing 
 bread to retain a larger proportion of water than it otherwise would, so that bakers 
 who use alum defraud their customers by selling water instead of bread, does not 
 appear to rost on satisfactory evidence. Odling (loc. cit.) examined the new crumb 
 of eighteen alumed and seven non-alumed loaves, and found that the former contained 
 
BREAD. 
 
 659 
 
 on the average 43-68 per cent., and the latter, 4278 per cent, water, the difference being 
 quite insignificant as compared with the differences between the individual loaves, 
 whether alumed or not. The detailed results, together with the proportions of 
 nitrogen and ash in the loaves, are given in the following table, the samples marked 
 with an asterisk beiug the wow-alumed loaves. They are interesting in a general point 
 of view, independently of the alum question. The loaves were new, that is, obtained 
 during the day on which they were baked. 
 
 Percentage of WATEK, NITBOGEN and ASH, in Bread Alumed and Non-aliimed. 
 
 
 Price in 
 Pence. 
 
 Percentage 
 of Water. 
 
 Percentage 
 of Organic 
 Matter. 
 
 Percentage 
 of Mineral 
 Matter or 
 Ash. 
 
 Percentage 
 of Ash in dry 
 Bread. 
 
 Percentage 
 of Nitrogen 
 in new 
 Bread. 
 
 'ercentage 
 uf Nitrogen 
 in dry 
 Bread. 
 
 1 
 
 4| 
 
 43-03 
 
 55-48 
 
 1-49 
 
 2-61 
 
 1-83 
 
 3-21 
 
 2 
 
 
 42-86 
 
 56-07 
 
 1-07 
 
 1-87 
 
 1-47 
 
 2-57 
 
 3 
 
 3- 
 
 44-81 
 
 53-74 
 
 1-45 
 
 2-62 
 
 1-89 
 
 3-42 
 
 4 
 
 3| 
 
 46-71 
 
 52-12 
 
 1-17 
 
 2-19 
 
 1-14 
 
 2-13 
 
 5 
 
 4 
 
 45-42 
 
 53-24 
 
 1-34 
 
 2-45 
 
 1-66 
 
 3-05 
 
 6 
 
 4 
 
 44-33 
 
 54-29 
 
 1-38 
 
 2-47 
 
 1-04 
 
 1-88 
 
 7* 
 
 4 
 
 44-41 
 
 54-38 
 
 1-21 
 
 2-17 
 
 1-06 
 
 1-90 
 
 8 
 
 3| 
 
 38-62 
 
 59-79 
 
 1-59 
 
 2-58 
 
 1-15 
 
 1-47 
 
 9* 
 
 3| 
 
 42-77 
 
 56-00 
 
 1-23 
 
 2-15 
 
 1-31 
 
 2-29 
 
 10 
 
 4 
 
 43-67 
 
 55-09 
 
 1-24 
 
 2-20 
 
 0-93 
 
 1-66 
 
 11* 
 
 *l 
 
 42-94 
 
 55-82 
 
 1-24 
 
 2-17 
 
 1-12 
 
 1-95 
 
 12 
 
 3| 
 
 44-20 
 
 54-61 
 
 1-19 
 
 2-13 
 
 1-14 
 
 2-05 
 
 13 
 
 4 
 
 45-12 
 
 53-55 
 
 1-33 
 
 2-43 
 
 1-17 
 
 2-15 
 
 14 
 
 ?1 
 
 44'34 
 
 54-41 
 
 1-25 
 
 2-28 
 
 1-23 
 
 2-21 
 
 15 
 
 4 
 
 43-70 
 
 55-07 
 
 1-23 
 
 2-18 
 
 1-01 
 
 1-81 
 
 16 
 
 1 
 
 43-06 
 
 55-59 
 
 1-35 
 
 2-39 
 
 1-24 
 
 2-18 
 
 17 
 
 4 
 
 43-90 
 
 54-92 
 
 1-18 
 
 2-11 
 
 1-13 
 
 2-03 
 
 18 
 
 4 
 
 42-12 
 
 56-65 
 
 1-23 
 
 2-12 
 
 1-23 
 
 2-14 
 
 19 
 
 4f 
 
 42-58 
 
 55-99 
 
 1-43 
 
 2-50 
 
 1-34 
 
 2-34 
 
 20* 
 
 4| 
 
 41-06 
 
 57-23 
 
 1-71 
 
 2-90 
 
 1-39 
 
 2-38 
 
 21* 
 
 4 
 
 44-07 
 
 54-67 
 
 1-26 
 
 2-26 
 
 1-08 
 
 1-94 
 
 22 
 
 4 
 
 44-46 
 
 54-22 
 
 1-32 
 
 2-38 
 
 1-18 
 
 2-14 
 
 23 
 
 4| 
 
 43-43 
 
 55-24 
 
 1-33 
 
 2-35 
 
 1-19 
 
 2-10 
 
 24* 
 
 41 
 
 42-89 
 
 55-68 
 
 1-43 
 
 2-52 
 
 1-17 
 
 2-05 
 
 25* 
 
 4 
 
 41-34 
 
 5776 
 
 0-90 
 
 1-54 
 
 1-33 
 
 2-27 
 
 JYLean. 
 
 A 
 
 1085-84 
 
 1381-61 
 
 32-55 
 
 57-57 
 
 31-53 
 
 55-72 
 
 
 :r 
 
 43-43 
 
 55-26 
 
 1-30 
 
 2-30 
 
 1-26 
 
 2-22 
 
 Lime-water has also been recommended to prevent the transformation of starch 
 during panification into dextrin, sugar, and lactic acid. It was first suggested by 
 Liebig, and is said to have been used to a considerable extent by the Glasgow bakers. 
 Odling finds, from laboratory experiments, that lime-water is quite as effective 
 as alum in preventing the action of diastase upon starch, but seems to have scarcely 
 any influence on the fermentation induced by yeast, or, at any rate, a much less action 
 than alum, which certainly retards the process in a perceptible degree. In this respect 
 then lime-water possesses an advantage over alum ; it would also doubtless be con- 
 sidered less objectionable in its direct action on the digestive organs. Bread made 
 with it is of agreeable taste, of rather more porous texture than ordinary baker's bread, 
 and quite free from sourness. 
 
 There are doubtless many other mineral substances which would act in the same way 
 as alum or lime-water. Thus sulphate of copper acts very powerfully in opposing 
 the action of diastase, and is said to have been used for that purpose in Belgium, an 
 ounce of the salt being dissolved in about a quart of water, and a wine-glassful of this 
 solution mixed with the water necessary for fifty quartern or four-pound loaves. This 
 quantity is extremely small ; nevertheless the use of so poisonous a substance as sul- 
 phate of copper cannot be too strongly condemned : bread containing copper would be 
 sure to act injuriously in the long run. 
 
 r u 2 
 
660 BREAD. 
 
 Mineral substances added to bread may be detected and estimated in the ash by 
 the ordinary processes of inorganic analysis. A few details may, however, be added 
 relating to the detection and estimation of alumina. The bread taken for examination 
 should be crumb, from the middle of the loaf; it should be carefully trimmed from 
 crust and outside crumb, as those portions may be dirty. It is then to be charred on 
 a platinum tray ; the charcoal reduced to powder and incinerated in a muffle (p. 418) ; 
 the ash digested in pure strong hydrochloric acid ; the filtered solution evaporated to 
 dryness to render silica insoluble ; the dried residue drenched with strong hydrochloric 
 acid, then boiled with water, and the liquid filtered. The acid filtrate must next be 
 nearly neutralised with carbonate of sodium, pure alcoholic potash added in excess, 
 which will precipitate earthy phosphates and retain alumina in solution, and the 
 liquid boiled and filtered; aqueous potash must not be used, as it always contains 
 alumina. The alkaline filtrate is then to be slightly supersaturated with hydrochloric 
 acid and boiled with carbonate of ammonium ; this will precipitate all the alumina, 
 which may then be collected, dried, and tested with nitrate of cobalt before the blow- 
 pipe. (See p. 155.) 
 
 If a quantitative determination is to be made, it must be remembered that the 
 alumina precipitate generally contains phosphoric acid. To estimate the amount of 
 this acid, the precipitate, after being weighed, is to be dissolved in hydrochloric acid, 
 the solution mixed with tartaric acid, excess of ammonia added (which will produce 
 no precipitate), and then sulphate of magnesium. The phosphoric acid will thereby 
 be precipitated as ammonio-magnesian phosphate, which is converted by ignition into 
 pyrophosphate of magnesium, Mg 4 P 2 7 , whence the quantity of phosphoric anhydride 
 (P 2 5 ) may be calculated, and this, deducted from the total weight of the alumina 
 precipitate, gives the quantity of alumina. Or the precipitated alumina containing 
 phosphate may be dissolved in nitric acid, a piece of metallic tin added, and the liquid 
 boiled : the tin is thereby oxidised, and remains as an insoluble powder, consisting 
 of stannic oxide and phosphate, the whole of the phosphoric acid being thus separated 
 from the alumina. The whole is next evaporated to dryness, the residue treated with 
 water and filtered, and the alumina precipitated from the filtrate by carbonate of 
 ammonia. 
 
 UNFERMENTED BREAD. Instead of using alum or other mineral substances, as 
 above described, to counteract the injurious secondary actions which take place during 
 the fermentation of dough, methods have been proposed, and to a certain extent carried 
 out, for dispensing with the fermentation altogether, and supplying the carbonic acid 
 which is to give lightness to the dough, from some extraneous source. 
 
 1. Instead of mixing salt (chloride of sodium) with the flour and water, hydrochloric 
 acid and carbonate of soda are added in the proportion required to form chloride of 
 sodium, the carbonic acid thereby evolved causing the dough to rise just as if it had 
 been generated by fermentation. Bread thus made is said to be of good quality, 
 though it is never so white as ordinary baker's bread. There is, however, a serious 
 objection to its constant use, namely, that it is liable to be contaminated with arsenic, 
 introduced by the hydrochloric acid. That acid indeed, as found in commerce, always 
 contains arsenic, the complete removal of which can only be effected by a process much 
 too costly and troublesome for the purposes of a bake-house ; and though the quantity 
 of arsenic actually present in the bread may be small, still by daily use it might accu- 
 mulate in the system and ultimately produce injurious effects. 
 
 2. Preparation of AERATED BREAD. Carbonic acid gas produced from chalk, either 
 by the action of dilute sulphuric acid or by ignition, and stored in an ordinary gas- 
 holder, is pumped therefrom into a cylindrical vessel containing water, whereby the 
 water becomes charged with the gas. This carbonic acid water is mixed under pres- 
 sure with the flour, and the resulting dough, which becomes vesicular on the removal 
 of the pressure, is divided into loaves and baked. This process, which was invented 
 and patented by Dr. Dauglish, has been carried out on a large scale in London and 
 other places. 
 
 The following is a description of the apparatus: A (fig. 112) is the mixer or vessel 
 in which the flour, water, and salt are mixed together. It consists of a very strong 
 iron spheroidal vessel, with an internal capacity of from 17 to 20 cubic feet. It has 
 an opening B at the top, to which an air-tight cover is fitted, and the means of closing 
 it to resist considerable pressure. There is also a corresponding opening C at the bottom, 
 large enough for a man-hole, and also closed by a lid, to which is attached the appa- 
 ratus for drawing off" the dough through suitable mouthpieces in a continuous stream, 
 which is cut into pieces by a boy, and received into boxes or baskets to be conveyed 
 to the oven. Through the centre of the mixer, a shaft passes furnished with stuffing 
 boxes, to prevent the escape of compressed gas, and in this shaft suitable mixing arms 
 are fixed : by means of the necessary gearing this shaft is made to rotate by steam 
 power. D is a copper water- vessel, having communication with the mixer from the 
 
BRExlD. 
 
 (J61 
 
 Fig. 112. 
 
 bottom by means of a valve, and from the top by means of a pipe passing up inside 
 the water-vessel. This water- vessel has also communication with a pair of condensing 
 pumps, which are fixed in the 
 same frame behind the mixer, 
 and are worked by a steam en- 
 gine. The communication is by 
 means of the pipe E, which ter- 
 minates within the water- vessel 
 by a rose perforated with minute 
 holes. 
 
 To work the apparatus, the 
 top cover B of the mixer is 
 opened, and about 560 Ibs. of 
 flour are shot into it by 
 means of a hopper and shoot 
 connecting with the floor above ; 
 water, to the amount of 30 gal- 
 lons or so, is drawn into the 
 water- vessel from a cistern above, 
 and the whole is then closed, 
 after adding to the flour the ne- 
 cessary salt. After removing 
 the air from the apparatus by a 
 suitable pump, carbonic acid 
 is pumped by the condensing 
 pump from a gas-holder, in which 
 it is stored until it is condensed 
 to about seven atmospheres. This 
 condensed gas being dispersed by 
 the rose at the bottom of the 
 water-vessel, passes in minute 
 streams through the water, and 
 as the density within increases, 
 the water absorbs the gas in pro- 
 portion, that which is not ab- 
 sorbed passing down the internal 
 pipe from the top of the water- 
 vessel into the mixer, so that 
 the density within that vessel 
 is kept in equilibrium with that 
 in the water- vessel. When the 
 right density is attained, the 
 valve at the bottom of the 
 water- vessel is opened, when the 
 water falls upon the flour, after 
 
 which the mixing arms are set to work, and in about six minutes the dough is thoroughly 
 formed. It is allowed to subside for a minute, and is then drawn off through the 
 bottom apparatus, being forced through it by the elastic force of the gas within. 
 On escaping from the condensed atmosphere in the mixer, the dough immediately 
 assumes the vesicular form and texture, and is ready to be baked. 
 
 The carbonic acid is obtained by acting on whiting or ground chalk with sulphuric 
 acid ; it comes off perfectly pure, and, being kept over water, is thoroughly washed. 
 It takes about 20 cubic feet of carbonic acid at atmospheric density to prepare dough 
 from 280 Ibs. of flour, about 11 cubic feet being incorporated with the dough, the re- 
 maining 9 cubic feet being wasted in the operation of drawing the dough off, and in 
 other ways : 7 Ibs. of sulphuric acid give, in practical working, 21 cubic feet of 
 carbonic acid from 10 Ibs. of carbonate of lime, the sulphuric acid being of density of 
 1-848. The gas which is left in the apparatus after the dough is discharged, is re- 
 turned to the gas-holder for further use. 
 
 The advantages of this process are thus stated by Dr. Odling in a paper read before 
 the Chemical Section of the British Association at Aberdeen in 1859: 1st. Its 
 cleanliness. Instead of the dough being mixed with the naked arms or feet, the 
 bread, from the wetting of the flour to the completion of the baking, is not, and 
 scarcely can be, touched by any one. 2nd. Its rapidity. An hour and a half serves 
 for the entire conversion of a sack of flour into baked loaves ; whereas, in the ordinary 
 process, four or five hours are occupied in the formation of the sponge, and a further time 
 in the kneading, raising, and baking of the dough. 3rd. Its preventing the glucogenic 
 
 v u 3 
 
662 BREAN BREITHAUPTITE. 
 
 deterioration of the flour, which takes place in the ordinary process (p. 657), and thereby 
 obviating the necessity of using alum. 4th, Its certainty and uniformity. Owing to 
 differences in the character and rapidity of the fermentation, dependent on variations 
 of temperature, quality of yeast, &c., the manufacture of fermented bread frequently 
 presents certain vagaries and irregularities from which the new process is entirely free. 
 5th. The character of the bread. Chemical analysis shows that the flour has under 
 gone less deterioration in bread made by the new than in that made by the fermenting 
 process. In other words, the percentage of extractive matters is smaller. The new 
 bread has been tried dieteticafiy at Guy's Hospital, and by many London physicians, 
 and has been highly approved of. It is well known that, for some years past, the use 
 of fermented bread in dyspeptic cases has been objected to by members of the medical 
 profession, the debris of the yeast being considered unwholesome, and liable to induce 
 acidity. 6th. Its economy. The cost of carbonic acid is alleged to be less than the 
 cost of yeast. Moreover, in making fermented bread, there is a small but necessary 
 waste of the saccharine constituents, which is avoided in the new process. 7th. The 
 saving of labour and health". It substitutes machine labour for manual labour of a 
 very exhausting kind. The sanitary condition of journeymen bakers was investigated 
 some time ago by Dr. Guy, and found to be most lamentable, from their constant 
 night work, and from the fatiguing and unwholesome character of their labour, par- 
 ticularly the kneading. In a politico- economical point of view, the process is also 
 important, as removing bread-making from a domestic manual work to a manufacturing 
 machine work. From the character of the apparatus, the process can only be used 
 profitably on a large scale, and not in small bakeries. 
 
 Of all the advantages just noticed, the most important is the prevention of the de- 
 terioration of the flour, which is so apt to occur in the ordinary process of bread- 
 making. . We have already observed (p. 657) that this deterioration consists in a too 
 great conversion of the starch into dextrin and sugar, and that it takes place to the 
 greatest extent when flour is used which contains the external as well as the central 
 portions of the wheat-grain, because the external portions are rich in nitrogenous 
 matter, the central consisting almost wholly of starch, and a portion of this matter 
 passing into a metamprphic state (diastase or cerealin) and acting as a ferment, 
 produces the change just mentioned. Now it is important that this external nitro^ 
 genous portion of the grain should be retained especially for persons who eat but 
 little meat, and to whom bread is essentially the staff of life, both for its direct 
 nutritive power, and for the part which the metamorphic gluten undoubtedly plays in 
 assisting the solution of the starch and unaltered gluten in the process of digestion. 
 In this country, however, there is an almost universal preference for white bread, and 
 consequently the miller contrives so to grind and dress his flour as to get rid as far as 
 possible of the nitrogenous portion, and thereby prevent the conversion of the starch 
 into dextrin and sugar during fermentation, which, as already observed, is the chief 
 cause of the loss of whiteness. Hence it is, perhaps, as Dr. Dauglish suggests, that 
 wheaten bread has not hitherto entered so extensively into the diet of the poor man 
 in England as oatmeal in Scotland. The latter is prepared for food by simply boiling 
 it in water in the form of a porridge, so that all the elements are presented to the 
 system uninjured by artificial processes, whereas our wheaten bread is generally prepared 
 in such a manner as to rob it of certain of those constituents which not only possess in 
 themselves great nutritive power, but like wise materially facilitate the digestion of the 
 whole. Now the new method of bread-making renders it possible to retain all these 
 matters, and at the same time to produce a light crumbly loaf, without the use of alum 
 or any other mineral ingredient. (See a paper by Dr. Dauglish read before the Society 
 of Arts, 25 April, 1860; also "On Fermented Bread and Aerated Bread," Medical 
 Times and Gazette, 12 May, 1860.) 
 
 For further details on the making of bread, and for descriptions and figures of 
 kneading machinery and patent ovens, see the article BREAD in Urc's Dictionary oj 
 Arts, Manufactures, and Mines, i. 400 ; Muspratfs Chemistry, i. 353 ; Payen, Precis 
 de Chimie IndustricUc, 4 rae ed. ii. 126; Handwortcrbuch d. Chem. 4 te Aufl. ii. [2] 511. 
 On the composition of wheat-grain, flour, and bread, see La wes and Gilbert. (Chem. 
 Soc. Qu. J. x. 1, 269.) 
 
 BREAM". See ICICA EESIN. 
 
 BREIDXNT and BRZSXN. See ARBOL-A-BREA. 
 
 BRETSI.AK.ITE. A mineral occurring in cavities of Vesuvian lava, in capillary 
 crystals. _ Chapman (Phil. Mag. [3] xxxvii. 444) regards it as a variety of augite. 
 The form is that of basaltic augite. Colour brownish or grey with metallic lustre. Melts 
 before the blowpipe to a shining magnetic Lead. Not attacked by boiling hydrochloric acid. 
 
 BREITHAUPTITE. Native anthnonide of nickel, Ni 2 Sb (p. 316). 
 
BREMER GREEN BRICKS. 663 
 
 BREAKER GREEN*. A green pigment consisting chiefly of basic carbonate of 
 copper mixed with alumina and carbonate of calcium. According to Bley, a fine blue- 
 green colour is obtained by dissolving commercial sulphate of copper in 10 pts. of 
 water, adding a little nitric acid, leaving the liquid to itself for a week, then filtering, 
 adding fresh lime-water, precipitating with filtered solution of pearl-ash, and mixing 
 the washed precipitate with gum- water to give it lustre. 
 
 BRETTNERXTE. See MAGXESITE. 
 
 BREVXCXTX*. See NJLTBOLITE. 
 
 2B.EWSTERXTE. A somewhat rare mineral, occurring in transparent colourless 
 prismatic crystals, of the monoclinic system, with the lateral faces inclined to the ter- 
 minal faces, at an angle of 93 40'. Specific gravity 2'12 to 2-2 (Brewster); 2*453 
 (Mallet). Hardness = 5'0 to 5'5. According to the following analyses by Connell 
 (Ed. N. Phil J. xiv. 35), Thomson (Mineralogy, i. 348), and Mallet (SilL Am. J. 
 [2] xxviii. 48), it is of the form M 2 O.Al 4 O s .6Si0 2 + 5H 2 0, the symbol M denoting 
 strontium, barium, and calcium in the atomic proportion Sr : Ba : Ca = 4:2:1, and 
 by regarding the water as basic and substituting aluminicum (a/ = 9'2) for aluminosum 
 (Al = 137), the formula may be reduced to M 2 aOTSi 6 21 , which is of the form 
 R s Si 2 T or R 4 Si0 4 .R 2 SiO 3 : 
 
 SiO 2 A1 4 S Ba 2 Si^ Ca 2 H 2 Fe 4 8 
 53-67 17-49 675 8'32 1-35 12-58 0'29 = 100-45 (Connell) 
 53-04 16-54 6-02 9'01 0'80 14-73 = 100-17 (Thomson) 
 62-42 15-25 6-80 8-99 1-19 13'22 trace = 97'87 (Mallet) 
 Before the blowpipe, it parts with its water and becomes opaque, then froths, and swells 
 up, but melts with difficulty. Leaves a silica skeleton when fused with phosphorus- 
 salt. Dissolves in acids, with separation of silica. It occurs at Strontiau in Argyleshire, 
 on the Giant's Causeway, in the lead mines at St. Turpet near Freiburg, in the 
 Breisgau, in the department of Is ere in France, and in the Pyrenees. 
 
 BREWSTOXfXN 1 . A liquid hydrocarbon found in minute cavities in crystals of 
 topaz, chrysoberyl, quartz from Quebec, and amethyst from Siberia, in which it was 
 detected by Sir D. Brewster. It is transparent and colourless, and is nearly thirty-two 
 times as expansible by heat as water, increasing one-fourth of its volume by an incre- 
 ment of 30, at 50 F. On exposure to the air, it undergoes quick motions and 
 changes, and finally evaporates, leaving a residue of minute solid particles, which, from 
 the moisture of the hand alone, suddenly become fluid again. The residue volatilises 
 by heat, and dissolves in acids without efflorescence. (Dana, ii. 471.) 
 
 BRICKS. Common bricks are made with clay mixed with sand or ashes, and 
 baked or burnt at various temperatures. In some southern countries, bricks are merely 
 dried in the sun, but they then remain very friable, and are fit only for light con- 
 structions. Nearly all sedimentary or alluvial formations contain clays which may be 
 used for making bricks. Some clays do not require any addition of sand, but with 
 plastic clays an admixture of sand is necessary. In this country, coal-ashes are mixed 
 with the clay, partly to give it the right consistence, partly to facilitate the burning. 
 The clay is dug up and turned over in the winter, and being thus exposed to wet 
 and frost, it breaks up and mixes better with the coal-ashes which are afterwards 
 added. For stiff clays, 50 chaldrons of ashes are added to 240 cubic yards of clay ; 
 for clays containing much sand, 40 chaldrons of ashes to 220 cubic yards of clay, and 
 these quantities make 100,000 bricks. The clay and ashes are mixed with water and 
 thoroughly incorporated, first by raking and afterwards in the pug-mill, which is an 
 iron-hooped barrel, in the centre of which is a vertical shaft, worked by a horse, and 
 bearing six knives, all of which, except the top one, are furnished with teeth. At the 
 bottom of the barrel, is a small hole, through which the masticated clay is forced by 
 the grinding of the teeth. The clay is next fashioned into bricks in rectangular 
 wooden moulds, previously sanded. The bricks are then dried in the air, and after- 
 wards made up into heaps called clamps, having flues or spaces left in them, which are 
 filled with dry wood, on which is put a covering of breeze, a coarse kind of coal-ash 
 left from the sifting. The clamp when full is surrounded with old bricks, and on the 
 top of all a thick layer of breeze is laid. The external bricks at the sides are coated 
 with a thin plastering of clay, to exclude the air, and in wet weather protected by 
 hurdles having rushes woven into them. The fire is lighted at the mouths of the 
 flues, which, if it burns well, are then stopped up. In favourable weather, the bricks 
 are burnt in about twenty-five or thirty days. In this mode of burning, the coal-ashes 
 incorporated in the substance of the bricks contribute greatly towards the effect. 
 Sometimes, however, bricks are burned in kilns, and then they have no ashes mixed 
 with them, the firing being wholly external. 
 
 Fin-bricks are bricks made of refractory clay, that is of clay which will stand a 
 
 v v 4 
 
664 BRICKS BROMACETIC ACID. 
 
 very strong heat without fusing. Such clays must be free from lime and oxide of 
 iron. The clay of Stourbridge in Worcestershire, and those of Burgundy are cele- 
 brated for their fire-resisting qualities, and are therefore used for making bricks for 
 lining furnaces. The clay is mixed with sand or with the fragments of old fire- 
 bricks ground to powder. (See Urcs Dictionary of Arts, Manufactures, and Mines, 
 i. 441.) 
 
 BRICKS (FLOATING). Bricks that swim on water were manufactured by the 
 ancients ; and Fabbroni discovered some years since, a substance, at Castel del Piano, 
 near Santa Fiora, between Tuscany and the States of the Church, from which similar 
 bricks might be made. It constitutes a brown earthy bed, mixed with the remains of 
 plants. Haiiy calls it talc pulverulent silicifere, and Brochant considers it as a variety 
 of meerschaum. The Germans name it BerrjmeM (mountain meal), and the Italians 
 latte di luna (moon milk). According to Klaproth's analysis, it consists of 79 silica, 
 5 alumina, 3 oxide of iron, 12 water, and 1 loss, in 100 pts. It agrees nearly in com- 
 position with Kicsclguhr. U. 
 
 BRILLIANT. Diamond cut in such a way as to reflect light most vividly, is 
 called a brilliant. See DIAMOKD. 
 
 BRIItlSTOCTE. See SULPHUR. 
 
 BRIWS3OWTA IWB-ICA. A plant belonging to the order Guttiferce. The 
 pericarp of the fruit is used in Goa as a spice, and the blood-red acid juice as a 
 lemonade. The seeds are convex, red-brown, tasteless, of the size of ordinary beans, 
 and contain 172 per cent, nitrogen, or after removal of the fat, 2'58 per cent. In the 
 dry state, they do not yield any fat by pressure, requiring to be previoiisly softened by 
 vapour of water ; by the use of solvents, 30 per cent, of fat may be extracted. The 
 crude fat is nearly colourless, melts at 40 C., dissolves sparingly in hot alcohol, and 
 easily saponifies, yielding glycerin, together with oleic and stearic acids, the latter 
 amounting to 50 per cent. From the crude fat, pure stearic is easily obtained by crys- 
 tallisation and pressing out the mother-liquor. The red-brown cake left after ex- 
 hausting the fat with ether, contains a fine red colouring matter, soluble in water and 
 alcohol, insoluble in ether and in acids. (J. Bouis and D'Oliveira Pimentef, 
 Compt. rend. xliv. 1355.) 
 
 BRIT ANNTA IVIETAL. An alloy of tin and antimony. (See TIN.) 
 
 ER3TKTTTJE. Syn. with GLAUBERITE. BRITISH GtTlW. See DEXTRIK. 
 
 BRITTLE SILVER ORE. Native sulphide of silver. See SLLVRB. 
 
 BROCATELLO. A calcareous stone or marble, composed of fragments of four 
 colours, white, yellow grey, and red. 
 
 BROCCOLI. See BBASSICA. 
 
 BROCHATUTITE. A basic sulphate of copper, Cu 7 S0 4 .6CuHO, found native, 
 associated with malachite and red copper ore, at Ekatherinenburg in Siberia, and at 
 Kezbanya in Hungary. Small right rhombic prisms of 117. Emerald-green, trans- 
 parent, with glassy lustre ; harder than calcspar. Specific gravity 3'80 3 '87. Melts 
 before the blowpipe, and forms a bead of reduced copper or charcoal. 
 
 BROBBBO TANTALITE. See TANTAUTE. 
 
 BROGNTARBITE. A sulphantimonite of lead and silver, 2PbAgS.Sb 2 S 3 , from 
 Mexico. It occurs in masses without cleavage. Lustre metallic. Streak greyish- 
 black. It is rapidly attacked by strong nitric acid. An analysis by Dam our (Ann. 
 Min. [4] xvi. 227) gave 19'38 per cent. S, 29'95 Sb, 25*03 Ag, 2474 Pb, 0'54 Cu, and 
 0-04 Zn. 
 
 BROGNIARTIXT or BROGNTARTITE. Syn. with GLAUBERITE. 
 
 BROMACETIC ACIB, C 2 H 3 Br0 2 . (W. H. Perkin and B. F. Duppa, Chem. 
 Soo. Qu. J. xi. 22.) 
 
 Formation. By the action of bromine on acetic acid : 
 
 C 2 H<0 2 + Br 2 = C 2 H 3 Br0 2 + HBr. 
 
 A small quantity of dibromacetic acid is formed at the same time. 
 
 Preparation. A mixture of glacial acetic acid and bromine in equal numbers of 
 atoms (an excess of acetic acid being used to absorb the hydrobromic acid and thereby 
 diminish the pressure) is introduced into a strong sealed tube, and heated in an oil- 
 bath to 150 C., and the bath is then left to cool gradually. When the temperature has 
 fallen to about 146, the mixture suddenly becomes nearly colourless, or light amber- 
 brown, and at the same time, the tubes are apt to burst, though the temperature of 
 the bath may have risen as high as 155. The tube when quite cold is opened, 
 torrents of hydrobromic ar-id gas then escaping; the contents are transferred to ;i 
 retort provided with proper apparatus for condensing the hydrobromic acid, and 
 
BROMACETIC ACID. 660 
 
 heated to 200; and the retort is left to cool. The whole conteLts then solidify 
 after a while into a beautifully crystalline mass, consisting of bromacetic and dibro- 
 macetic acids, mixed with a little hydrobromic acid, to remove which the mixture 
 is heated to 130, and carbonic acid gas passed through it till the presence of hydro- 
 bromic acid is no longer indicated by nitrate of silver. Carbonate of lead is then 
 added in excess, together with a volume of water about ten times as great as that of 
 the acid; and the whole is heated to 100, and allowed to stand for some hours. 
 Bromacetate of lead then crystallises out, while dibromacetate remains in solution. 
 The crystals may be freed from the last portions of this salt by washing with a little 
 cold water. Lastly, the crystals of bromacetate of lead are suspended in water and 
 decomposed by sulphuretted hydrogen, and the filtered liquid is evaporated till it 
 crystallises. 
 
 Bromacetic acid forms rhombohedral crystals which are very deliquescent. It melts 
 below 100 C., and boils at 208 ; attacks the skin powerfully, raising a blister like a 
 burn ; when the acid is dilute, this effect takes place after eight or ten hours only. It 
 is very soluble in water. 
 
 The acid strongly heated in a sealed tube, is resolved into dibromacetic acid, 
 carbonic oxide, and apparently marsh-gas, together with water and hydrobromic acid, 
 probably as represented by the equation : 
 
 3C 2 H 3 Br0 2 = C*H 2 Br 2 2 + SCO + CH 4 + HBr + H 2 0. 
 
 On distilling it with acetate of potassium, acetic acid is evolved. Heated with 
 metallic zinc, it yields acetate and bromide of zinc. Heated with ammonia, it forms 
 bromide of ammonium and glycocine : 
 
 C 2 H 3 Br0 2 + 2NH 3 = NH 4 Br + C 2 H 5 N0 2 . 
 
 The acid is monobasic, the formula of its salts being C 2 H 2 Br0 2 .M. Most of them 
 are crystallisable and many of them decompose rapidly. 
 
 Bromacetate of Ammonium. Nearly uncrystallisable ; very soluble in water; de- 
 composes when heated, yielding bromide of ammonium. 
 
 Bromacetate of Barium crystallises with difficulty in small stars containing water 
 of crystallisation ; it is tolerably soluble in alcohol. 
 
 Bromacetate of Calcium is a very difficultly crystallisable salt, very soluble in water. 
 
 Bromacdate of Copper is a green crystalline salt, very soluble in water. A 
 solution of it appears to decompose when boiled, as the colour becomes paler. The 
 solution, after standing for some days, deposits needle-shaped crystals and small mala- 
 chite-green tufts of great beauty, which appear to contain a large quantity of water of 
 crystallisation. 
 
 Bromact tate of Lead. Obtained, either by neutralising bromacetic acid with oxide 
 of lead and recrystallising the product from water ; or by adding a solution of brom- 
 acetic acid to a solution of acetate of lead, washing the resulting crystalline precipitate 
 with cold water, and recrystallising from water. Crystallises in needles, sparingly 
 soluble in cold, but moderately soluble in hot water. 
 
 Bromacetate of Potassium. Obtained by neutralising a solution of carbonate or 
 hydrate of potassium with bromacetic acid, and evaporating the solution in a water- 
 bath. It is a crystalline salt, very soluble in water and alcohol. 
 
 Bromacetate of Silver. C 2 H 2 BrAg0 2 . Obtained by treating bromacetic acid 
 with carbonate of silver, or by adding a solution of bromacetic acid to a solution of 
 nitrate of silver. In the latter case, it is thrown down as a beautiful crystalline pre- 
 cipitate, which may be washed with cold water, and dried over sulphuric acid in vacuo. 
 Contains 43'62 per cent, silver (by calculation, 43'9). It is very unstable. The dry 
 salt heated to about 90 C., decomposes with a sort of an explosion. It is rapidly acted 
 upon by light when moist. Boiled with water, it yields bromide of silver and glycollic 
 acid: 
 
 C 2 H 2 BrAg0 2 + H 2 = AgBr + C 2 H 4 8 . 
 
 Bromacetate of Sodium is very soluble in water, but insoluble, or nearly so, in 
 alcohol. 
 
 BROMACETIC ETHERS. Bromacetate of Methyl, C 3 H 5 Br0 2 = C 2 H 2 Br0 2 .CH 3 , is ob- 
 tained by heating amixture of methylic alcohol and bromacetic acid in a sealed tube 
 for an hour, to a temperature of 100 C., washing the product with water, drying over 
 chloride of calcium, and rectifying. It is a transparent, colourless, mobile liquid, having 
 an aromatic odour highly irritating to the nose and eyes. It is heavier than water ; 
 boils at about 144 C., decomposing gradually every time it is distilled. Ammonia acts 
 on it very readily. 
 
 Bromacetate of Ethyl. C 4 H 7 Br0 2 = C 2 H 2 Br0 2 .C*H 5 . Obtained in a similar 
 manner to tho preceding. It is a clear colourless liquid, heavier than water, and 
 
666 BROM ACETIC ACID BROMAL. 
 
 highly irritating to the eyes and nose. It boils at 159 C. Decomposes partially every 
 time it is distilled, with evolution of hydrobromic acid. It is rapidly acted on by 
 ammonia. 
 
 Bromacetate of Amyl. C 7 H 13 Br0 2 = C 2 H'-'Br0 2 .C 5 H". Obtained by heating amylic 
 alcohol with excess of bromacetic acid, washing the product with water, and drying 
 over chloride of calcium. It is an oily liquid which has a pleasant odour when cold, 
 but if heated, acts upon the eyes and nose like the preceding. It boils at 207 C., and 
 decomposes partially every time it is distilled. Ammonia acts but slowly upon it in 
 the cold. 
 
 The bromacetates of methyl, ethyl, and amyl, boil at temperatures about 82 to 86C. 
 higher than the acetates. Thus 
 
 Boiling-point. Boiling-point. Diff. 
 
 Bromacetate of Methyl . 144 C. Acetate of Methyl . 58 C. 86 
 
 Ethyl. . 159 Ethyl . 74 85 
 
 Amyl . . 207 Amyl . 125 82 
 
 A similar difference exists between the boiling points of bromacetic acid (208), and 
 acetic acid (120). 
 
 Dibromacetic Acid. C 2 H 2 Br 2 2 . (Perk in andDuppa, Chem. Soc. Qu. J.xii. 1.) 
 Formed, together with monobromacetic acid, when a mixture of bromine and acetic 
 acid is exposed to light (p. 663). To obtain it in quantity, the monobrominated acid 
 is exposed to the action of bromine-vapour in strong sunshine. The product may be 
 freed from hydrobromic acid by passing a stream of dry carbonic acid gas through it 
 at 120 C. 
 
 It is a colourless, inodorous liquid, of specific gravity 2 '25 ; it was once, during very 
 cold weather, obtained in fine needle-shaped crystals. When placed on the skin, it 
 produces painful blisters like burns. It boils between 225 and 230 C., but cannot be 
 distilled without decomposition. It dissolves readily in water, producing cold ; also 
 in alcohol and ether. Zinc decomposes it, with evolution of hydrogen. 
 
 Dibromacctate of A mmonium. C 2 H 2 Br'-'0 2 .NH 4 + 1 aq. Obtained by neutralising the 
 acid with dilute ammonia and leaving the solution to evaporate, either in the air 
 or over sulphuric acid in vacuo. Forms splendid crystals, which give off their water 
 at 100, becoming white and opaque. Heated to 100 C. with excess of ammonia, it is 
 decomposed, giving off volatile products, which have not yet been examined. It dis- 
 solves readily in water, alcohol, and ether. 
 
 Dibromacetate of Potassium is a beautifully crystalline salt, shooting out into 
 long and very brilliant crystals, containing water of crystallisation ; very soluble in 
 alcohol and water, but not deliquescent. 
 
 Dibromacetate of Lead is a very soluble and uncrystallisable substance, drying up 
 to a tough gum-like mass. When added to water in excess, it fuses and runs about 
 like a heavy oil ; it is formed by adding the acetate or carbonate of lead to dibrom- 
 acetic acid. 
 
 Mercurous Dibromacetate is precipitated on adding a solution of mercurous nitrate 
 to dibromacetic acid ; it much resembles dibromacetate of silver, and like it undergoes 
 decomposition when boiled. 
 
 Dibromacetate of Silver is formed by adding the carbonate or nitrate of silver 
 to dibromacetic acid ; it crystallises in small needles, often grouped in stars when 
 the acid is dilute. It is easily decomposed at 100 C. yielding bromide of silver and 
 bromogly collie acid : 
 
 C 2 HBr 2 O.Ag.O + IPO = C 2 HBrO.H 2 .0 2 + AgBr. 
 
 Dibromacetate Bromoglycollic 
 
 of silver. acid. 
 
 Dibromacetic acid heated with ethylic and amylic alcohols, yields the corresponding 
 ethers. The ethyl-compound is decomposed by ammonia, yielding alcohol and 
 dibromacet amide: 
 
 C 2 HBr 2 .C 2 H 5 .0 2 + NIP = C 2 H 5 .H.O + N.H 2 .C 2 HBr 2 0. 
 
 BROM ACETIltfS, See ACETINS. 
 
 BR01WEAI.. Hydride of Tribromacetyl. Oxide de Bromethile. C 2 HBr 3 = C-Br'O.H. 
 (Lowig, Ann. Ch. Pharm. iii. 228.) A compound analogous to chloral, and produced 
 in like manner, by the action of bromine on alcohol. 3 or 4 pts. by weight of bromine 
 are gradually added to 1 pt. of absolute alcohol, cooled by ice ; the mixture is left to 
 itself for ten or twelve clays, and then distilled; and after three-fourths (consisting of 
 hydrobromic acid, bromide of ethyl, and other products) have passed over, the residue 
 is mixed with water, and exposed to the air for a day or more in a shallow basin. It 
 then deposits largo crystals of hydrate of bronuil, which yield the anhydrous compound 
 by distillation with sulphuric acid. Or they may be gently heated with six times their 
 
BROMALOIN BROMH YDRINS. 667 
 
 weight of strong sulphuric acid, and the anhydrous bromal, which then sinks to the 
 bottom as a colourless oil, may be separated by decantation and distilled, first over 
 slaked and then over quick lime. 
 
 Bromal is said to be also produced by the action of bromine on a mixture of alcohol 
 and nitric acid. (Aime.) 
 
 Bromal is a transparent colourless oil, of specific gravity 3*34. It is somewhat greasy 
 to the touch, and makes grease-spots upon paper, which however soon disappear. Its 
 boiling point is above 100 C. and it may be distilled without decomposition. It has a 
 peculiar pungent odour, and excites a copious flow of tears. Its taste is extremely 
 sharp and burning, and very persistent. 
 
 Bromal is decomposed by aqueous alkalis in the same manner as chloral, yielding 
 bromoform, CHBr 3 , and a formate of the alkali-metal. Lime and baryta heated in its 
 vapour become incandescent, and decompose it, yielding carbonic oxide, water, and 
 a bromide of the metal mixed with charcoal. Eed-hot iron acts in a similar manner. 
 It is not decomposed by nitric acid, sulphuric acid, or chlorine. 
 
 Hydrate of Bromal. C 2 HBr 3 0.2H 2 0. Bromal dissolves in a small quantity of 
 water, and the solution, when left to evaporate, yields the hydrate in large crystals, 
 having the form of sulphate of copper. They melt at the heat of the hand, dissolve 
 readily in water, and yield anhydrous bromal when treated with sulphuric acid. The 
 hydrate is also formed when bromal is exposed to moist air. 
 
 Bromal dissolves sulphur and phosphorus, and mixes readily with bromine, also with 
 alcohol and ether. 
 
 BItOIVCALOIW. See ALOLN (p. 148). 
 
 BROMAXVXXX>E. See NITROGEN, BROMIDE OF. 
 
 SRO2MLA.T?XXa. Syn. of PERBROMOQUINONB. See QUINONE. 
 
 SaOIVI^LTSriLABSIC ACID. BRO1VXANXX.XC ACID. BROIMCAXTXIiA- 
 ZKCXDB. Syn. with DIBKOMOQUINONAMIO Aero, DIBROMOQUINONIC ACID, and DIBRO- 
 MOQUINOXAMIDE. (See QUINOXIC ACID.) 
 
 BROlKANXXiOXDX:. See TRLBROMOPHENYLAMINE, under PHENYLAMINE. 
 BROTCANISXC ACZXJ. See ANISIC ACID. BROlKAKTXSOXi. See ANISOL. 
 BROlML&RGYRXTi:. Native bromide of silver. (See SILVER.) 
 BRO1VIEITJ. C^H^r 4 ? A crystalline product, obtained in small quantity by 
 the action of bromine on crude benzene. (Laurent.) 
 
 BROMETHERXDE, BROXVEETHERXN, BROIVIETHEROIDE. See VINYL, 
 BROMIDE OF. 
 
 BROHXETKXOBJESSXXi. A product of the action of bromine on thionessal (q. v.) 
 It forms colourless tables, apparently consisting of C 2B H 14 Br 4 S. (Laurent.) 
 BROXVIHITDRXC ACXX>. See BROMIDE OF HYDROGEN. 
 
 BROMHYZ>RXlrS. (Berthelot and De Luca, Ann. Ch Phys. [3] xlviii. 304; 
 lii. 433.) These compounds are produced by the action of tribromide or pentabromide 
 of phosphorus on glycerin. Their composition is such as might result from the com- 
 bination of glycerin and hydrobromic acid, with elimination of water, and may be 
 represented empirically by the general formula 
 
 m C 3 H 8 3 + n HBr - p H 2 0. 
 Their names and formulae are as follows : 
 
 Monobromhydrin . . C 3 H 7 Br0 2 = C 3 H 8 3 + HBr - H 2 O 
 Epibromhydrin . . C 3 H 5 BrO = C 3 H 8 O 3 + HBr - 2H 2 O 
 Dibromhydrin . . C 3 HBr 2 = C 3 H 8 3 + 2HBr - 2H 2 O 
 Tribromhydrin . . C 3 H 5 Br 3 = C 3 H 8 3 + 3HBr - 3H 2 
 Hemibromhydrin . . C 6 H 9 Br0 2 = 2C 3 H 8 3 + HBr - 4H 2 O 
 Hexaglyceric Bromhy- C1 8 H 27 Br0 7 = 6C 3 H 8 3 + HBr - 11H 2 
 drin .... 
 
 Mono-, di-, and tribromhydrin, may also be regarded as glycerin, C S H 5 (HO) 3 , in 
 which 1 or more at. of peroxide of hydrogen has been replaced by bromine. 
 
 Besides these compounds, there are formed at the same time others of similar nature, 
 which have not been examined; likewise acrolein, and dibromallylphosphine, C 6 H 9 Br 2 P = 
 P.H 2 .(C 3 H 4 Br) 2 . 
 
 The bromhydrins heated with aqueous potash to 100 C., in closed vessels, all yield 
 bromide of potassium and glycerin. 
 
 Preparation of the Bromhydrins. 500 grms. of glycerin are added by small por- 
 tions to between 500 and 600 grms. of liquid bromide of phosphorus, the liquid bt'ing 
 cooled after each addition, and the mixture, after standing for twenty-four hours, is 
 distilled into a well-cooled receiver communicating with a vessel containing potash-Icy, 
 
668 BROMHYDRINS. 
 
 to absorb the acrolein vapour. As an additional precaution against the injurious effects* 
 of this vapour, the distillation and all the subsequent operations should be performed 
 either in the open air, or under a chimney with a good draught. 
 
 The distillate, consisting of an upper watery layer and a lower liquid insoluble in 
 water, may be freed from part of the acrolein by heating it in the water -bath. It is 
 then mixed with potash in sufficient quantity to supersaturate the acid and destroy 
 the acrolein, and the watery layer is separated from the lower liquid. 
 
 The watery liquid is then treated with ether, whereby an ethereal solution is ob- 
 tained, which, when quickly evaporated, leaves a residue chiefly consisting of the most 
 volatile products of the reaction, together with epibromhydrin. The lower liquid, 
 which is insoluble in water and requires to be treated for several hours with sticks of 
 potash, consists chiefly of epibromhydrin and dibromhydrin. The residue which re- 
 mains in the retort after the distillation, is suspended in water, supersaturated with 
 carbonate of potassium, and shaken up with ether, and the filtered etheral extracts 
 are evaporated : they then leave a mixture of dibromhydrin, monobromhydrin, and 
 several other substances. 
 
 To separate the individual substances contained in these several mixtures, the mix- 
 tures are subjected to repeated fractional distillation, and the portion which does not 
 volatilise at 240 C. under the ordinary atmospheric pressure, is fractionally distilled 
 under diminished pressure (about 10mm. of mercury). The distillate thus obtained 
 between 120 and 160 consists chiefly of dibromhydrin ; between 160 and 200, the 
 compound C 6 H 9 Br 2 P passes over together with monobromhydrin, and between 200 
 and 300, syrupy liquids which cannot be further separated, but appear to be brom- 
 hydrins. In the retort there remains a thick syrup, together with a black crystalline 
 compound which is hcxaglyceric bromhydrin. 
 
 Monobromhydrin, C 3 H 7 Br0 2 = (C 3 H 5 )'" (HO)^Br. This compound, which passes 
 over at 1 80 C. in the distillation under diminished pressure, is a neutral oily liquid, 
 soluble in ether, and having a sharp aromatic taste. 
 
 Dibromhydrin, C 3 H 6 Br 2 = (C 3 H 5 )'".HO.Br 2 . This, which is the chief product 
 of the action, is a neutral liquid, of specific gravity 2 - ll at 18 C. boiling at 219, 
 having an ethereal odour, and soluble in ether. Heated with pentabromide of phos- 
 phorus, it yields tri bromhydrin. Heated to 140 with metallic tin, it is decomposed, 
 yielding bromide of tin and a tin-compound insoluble in water but soluble in ether.' 
 
 "When gaseous ammonia is passed into pure dibromhydrin, the liquid becomes 
 hot, and yields bromide of ammonium, together with an amorphous substance, 
 C 6 H 12 BrN0 2 , insoluble in water, ether, alcohol, and acetic acid : 
 
 2C 3 H 6 Br 2 + 4NH 3 = 3NH 4 Br + C 6 H 12 BrN0 2 ; 
 
 but if the ammonia gas is passed into a solution of dibromhydrin in absolute alcohol, 
 
 the products formed are bromide of ammonium and hydrobromate of glyccramine : 
 
 C 3 H 6 Br 2 + (NH 4 ) 2 = NH 4 Br + C 3 H 9 N0 2 .HBr. 
 
 Tribromhydrin. C 3 H 5 Br 3 . Obtained by distilling dibromhydrin or epibrom- 
 hydrin with pentabromide of phosphorus, treating the product with water, distilling, 
 and collecting apart that which passes over between 175 and 180 C. It is a heavy 
 liquid, which fumes slightly in the air, is gradually decomposed by water, and when 
 treated with moist oxide of silver, yields bromide of silver and glycerin. It is 
 isomeric with "Wurtz's tribromide of allyl (called by Berthelot and JDe Luca, isotri- 
 bromhydriri), and with dibromide of bromotritylcne, C 3 H 5 Br.Br 2 . 
 
 Epibromhydrin or Oxybromide of G-lyceryl. C 3 H 5 BrO. This compound 
 is produced in considerable quantity by the action of the bromides of phosphorus on 
 glycerin. It may be isolated by repeated fractional distillation, the portions which boil 
 at or near 138 C. being each time collected apart. It is a mobile neutral liquid, 
 soluble in ether, with an ethereal odour and pungent taste. Specific gravity 1*615 at 
 14 C. Boils at 138. Vapour-density, by experiment, 578. (This is considerably 
 above the calculated value, 4'80, probably because the density was taken at a tempera- 
 ture too near the boiling point, viz. at 178, the compound decomposing rapidly at 
 higher temperatures.) 
 
 This compound may be considered as deriving from tribromhydrin, by the substitu- 
 tion of O for Br 2 . It is isomeric with bromide of propionyL C 3 H 5 O.Br. Its formula 
 is also that of monobromhydrin minus H 2 0, or of dibromhydrin minus HBr. 
 
 Epibromhybrin, heated with aqueous potash to 100 for 112 hours, saponifies, yielding 
 bromide of potassium, glycerin, and a trace of matter soluble in ether. Moist oxide 
 of silver decomposes it rapidly at 100, forming bromide of silver and glycrrin. Dis- 
 tilled with pentabromide of phosphorus, it is partly converted into tribromhydrin, ac- 
 cording to the equation : 
 
 C'IPBrO + PBr'Br 2 = PBr'O + CH s J5r, 
 
BROMIC ACID. 669 
 
 while the rest undergoes more complete decomposition, yielding a black substance and a 
 gaseous mixture, containing, in 100 volumes, 5'5 carbonic anhydride, 5-5 tritylene, 11*0 
 hydrogen, and 78'0 carbonic ozide. 
 
 Hexaglyceric Bromhydrin. C' 8 H 27 Br0 7 . This compound remains in the 
 retort in "the form of a black crystalline mass, impregnated with a syrupy liquid. It is 
 purified by washing with cold ether ; boiling ether dissolves it slightly. 
 
 Hemibromhydrin. C 6 H 9 Br0 2 . This compound passes over in the fractional 
 distillation between epibromhydrin and dibromhydrin, viz. at 200 C. It is a neutral 
 liquid, soluble in ether, and saponifiable by potash, yielding bromide of potassium, a sub- 
 stance analogous to or identical with glycerin, and a trace of matter soluble in ether, 
 The analyses of the compound are said to agree nearly with the above formula (no 
 analyses are given in Berthelot and De Luca's memoir), according to which it may be 
 regarded as derived from epibromhydrin, in the same manner as the latter from 
 dibromhydrin, viz. by abstraction of half the hydrobromic acid : 
 
 C s H 6 Br 2 - HBr = C 3 H 5 BrO : 
 and 
 
 2C 3 H 5 BrO - HBr = C 6 H 9 Br0 2 . 
 
 It is analogous in composition to iodhydrin. 
 
 BROXVXXC ACID. HBrO 3 or H 2 O.Br 2 5 . This acid is produced: 1. By the 
 action of bromine on alkalis or alkaline earths : 
 
 6Br + 3K 2 = KBrO 3 + 5KBr. 
 
 The bromate is separated from the bromide by its inferior solubility. A similar re- 
 action takes place with trioxide of gold, the products being bromate and bromide of 
 gold: 
 
 18Br + 3Au 8 3 - ^o 3 -f SAuBr 3 . 
 
 2. In the decomposition of pentachloride of bromine by water or by alkalis : 
 BrCP + 3H 2 = HBrO 3 + 5HC1. 
 
 To obtain the free acid (bromate of hydrogen) the barium-salt is decomposed with 
 an exactly equivalent quantity of dilute sulphuric acid, and the filtrate concentrated 
 by evaporation at a gentle heat. It cannot, however, be reduced to a syrupy con- 
 sistence without decomposition. The solution is colourless, acid to the taste, reddens 
 litmus, and then bleaches it. It is decomposed at 100 C., giving off bromine and 
 oxygen. All reducing agents decompose it with facility. With sulphurous acid the 
 products are bromine and sulphuric acid ; with sulphydric acid, water, bromine, and 
 sulphur ; with hydriodic acid, water and bromide of iodine ; with hydrochloric acid, 
 water and chloride of bromine ; with hydrobromic acid, water and bromine, e. g. : 
 
 HBrO 3 + 5HC1 = 3H 2 + BrCl 5 . 
 
 Alcohol and ether decompose bromic acid, with formation of acetic acid and great rise 
 of temperature. 
 
 Bromic acid is monobasic, the formula of the BROMATES being MBrO 3 or M 2 O.Br 2 5 . 
 Most of these salts are soluble in water, though less so than the bromides. They may 
 be prepared by the action of bromic acid on the oxides or carbonates of the metals, or 
 by precipitating bromate of barium with the corresponding sulphates ; the bromates 
 of the alkali-metals also by treating the solutions of the alkalis with bromine-water or 
 pentachloride of bromine, and crystallising out the sparingly soluble bromate from the 
 bromide or chloride formed at the same time : 
 
 6KHO + Br 8 = KBrO 3 + 3H 2 + 5KBr 
 6KHO + BrCP = KBrO 3 + 3H 2 + 5KCL 
 
 Bromates are for the most part crystallisable, but many of them decompose when their 
 solutions are heated ; hence it is generally best to evaporate the solutions in vacuo or 
 over oil of vitriol. The bromates of mercurosum, silver, and lead are insoluble. 
 
 Bromates heated to redness either give off their oxygen and leave bromides (K, Na, 
 Hg, Ag), or they give off bromine and part of their oxygen, and leave oxides, e.g. : 
 
 2ZnBr0 3 = Br 2 + O 5 + Zn 2 0. 
 
 Mixed with charcoal, sulphur, or other combustible substances, they explode by heat 
 or by percussion. Solid bromates Cheated with sulphuric acid, give off bromine and 
 oxygen. A solution of a bromate is coloured red, even by dilute sulphuric acid. By 
 sulphurous acid and other reducing agents, they are decomposed in the same manner 
 as the acid. A solution of a bromate, not too dilute, gives with lead-salts, a white pre- 
 
670 BROMIC ACID. 
 
 cipitate ; with mercurous salts, a yellowish white precipitate, insoluble in cold nitric 
 acid; and with silver-salts, a white precipitate almost insoluble in water, sparingly 
 soluble in nitric acid, easily in ammonia. This precipitate is distinguished from 
 chloride of silver by giving off red vapours of bromine when heated with sulphuric 
 acid. The reactions with silver-salts and with sulphuric acid distinguish bromates 
 from chlorates (j.f.) 
 
 BROMATE OF ALUMINIUM. Obtained as a clear, viscid, deliquescent mass, by dissolv- 
 ing hydrate of aluminium in bromic acid, or by precipitating bromate of potassium 
 with silicofluoride of aluminium, and evaporating the filtrate over sulphuric acid. 
 
 BROMATE OF AMMONIUM. Nil 'BrO 3 . White needles or crystalline granules, appa- 
 rently belonging to the regular system. It cannot be preserved in the solid state, as 
 it decomposes after a while, with violent detonation, even at ordinary temperatures, 
 yielding nitrogen, bromine, oxygen, and water. Hydrochloric acid decomposes it, 
 forming, however, but a small quantity of chloride of ammonium. 
 
 BROMATE OF BARIUM. 2BaBr0 3 + aq. When bromine or chloride of bromine is 
 added to baryta- water till the colour begins to be permanent, bromate of barium crystal- 
 lises out, while bromide or chloride remains in solution. But a better mode of prepara- 
 tion is to decompose 100 pts, bromate of potassium dissolved in boiling water, with 
 74 pts. crystallised chloride or 78 pts. anhydrous acetate of barium, and leave the 
 liquid to cool slowly ; the bromate of barium then separates out, while chloride or 
 acetate of potassium remains in solution. Acetate of barium is preferable to the 
 chloride for this preparation, on account of the greater solubility of the acetate of 
 potassium. 
 
 Bromate of barium forms a crystalline powder or thin prisms of the mouoclinic 
 system, with the faces coP . ooP o> . ( ooP oo) . Poo . oP . + P oo. co P. Inclination of 
 faces, o=P : ooP = 82 10' ; (P oo) : (P oo) = 79 5' ; oP : ooP oo = 93 2' ; ooP oo : 
 Poo = 138. The salt is isodimorphous with chlorate of barium (Eammelsberg, 
 Pogg. Ann. xc. 16). It dissolves in 130 pts. of cold and 24 pts. boiling water. It 
 does not give off its water of crystallisation till heated above 200 C. When thrown 
 on red-hot coals, it detonates with a green light. When heated alone, it is resolved, 
 with evolution of light and heat, into bromide of barium and oxygen gas, without 
 forming a perbromate. Hydrochloric or moderately dilute sulphuric acid decomposes 
 it with separation of chloride of bromine or free bromine; very dilute sulphuric acid 
 sc parates undecomposed bromic acid. 
 
 BROMATE OF BISMUTH. When bromic acid is poured upon hydrate of bismuth, a 
 basic insoluble salt is formed, together with a small quantity of dissolved salt. The 
 basic salt, 3Bi :2 O s .2Br 2 O 5 + 6 aq., is a white amorphous powder. 
 
 BROMATE OF CADMIUM. 2CdBr0 8 + aq. Rhombic prisms of 127 and 53, with 
 four-sided summits and truncation of the acute lateral edges by two narrow faces. 
 Soluble in 0-8 pts. cold water. Decomposed by heat, leaving oxide of cadmium mixed 
 with bromide. 
 
 Ammonio-bromide of Cadmium, 3NH 3 .CdBr0 3 , is deposited from an ammoniacal 
 solution of bromide of cadmium evaporated over quick lime, as a white crystalline 
 powder, which gives off ammonia when heated, and is decomposed by water. 
 
 BROMATE OF CALCIUM. 2CaBr0 3 + aq. Monoclinic tables or needle-shaped 
 prisms ; ooP : ooP in the clino-diagoual section = 79 56' ; ooP 2 : ooP 2 in the same = 
 118 22' ; + P' : + P in the same = 98 41' : - P : - P in the same = 106 22' : 
 (ip co) : (IP oo) in the same = 123 33' (Rammelsberg). Dissolves at mean_ tempe- 
 rature in ri pt. water, forming a syrupy solution. The crystals gives off their water 
 at 180 C. ; at a stronger heat, oxygen is given off and bromide of calcium remains. 
 
 BROMATE OF CERIUM. 2CeBr0 3 + aq. Colourless laminae, which dissolve easily in 
 water, and do not effloresce over sulphuric acid. 
 
 BROMATE OF CHROMIUM. Chromic sulphate decomposed by bromate of barium 
 yields a green filtrate, which decomposes by evaporation, giving off bromine and leav- 
 ing a dark red residue, consisting almost wholly of chromic acid. 
 
 BROMATE OF COBALT. CoBrO*+3aq. Hyacinth-red, transparent octahedrons, 
 soluble in 2'2 pts. water; the solution is decomposed by heat. The dry salt when 
 heated leaves a residue of oxide of cobalt. The salt dissolves in aqueous ammonia, 
 forming a red liquid which turns brown in the air, and yields, after filtration, dark- 
 brown crystals, probably consisting of the bromate ofFremy'sfitscocobaltia. 
 
 BBOMATE OF COPPER, 2CuBr0 8 + 5 aq., crystallises from a concentrated solution in 
 light-blue or blue-green crystals, which are very soluble in water, do not effloresce in 
 the air, but crumble to a greenish-white powder in vacuo over sulphuric acid. They 
 retain a small portion of their water even at 180 C., but give it off at 200, together 
 with part of the bromine. The aqiieous solution mixed with a little ammonia yields 
 
BROMIC ACID. 671 
 
 a light-blue precipitate, consisting of a basic salt, 6Cu 2 O.Br 2 5 + lOaq., which at 200 
 gives off its water and becomes greyish-green. 
 
 Ammonio-bromate of Copper, 2NH 3 .CuBr0 3 , separates as a dark-blue crystalline 
 powder on adding alcohol to a solution of bromate of copper in excess of ammonia. It 
 dissolves in a small quantity of water, and is decomposed by excess of water, with 
 separation of a basic salt. When heated it decomposes with deflagration. 
 
 BROMATES OF IRON. A solution of ferric hydrate in bromic acid, yields by evapora- 
 tion over sulphuric acid, a syrup, which, after drying over the water-bath, leares a 
 nearly pure basic salt, 5Fe 4 3 .Br 2 5 +30 aq., insoluble in water. 
 
 A solution of ferrous carbonate in bromic acid yields by evaporation in vacuo, octa- 
 hedral crystals of neutral ferro its bromate, FeBrO 3 , the solution of which easily de- 
 composes, with separation of the basic ferric salt. 
 
 BROMATE OF LANTHANUM. LaBrO 3 -f 3 aq. Amethyst-coloured crystals (? con- 
 taining didymium), which give off 20 per cent, water at 160 C. 
 
 BROMATE OF LEAD. 2PbBr0 3 + aq. Obtained by precipitation, or better by dis- 
 solving carbonate of lead in warm bromic acid ; it then crystallises on cooling in small 
 shining prisms, isomorphous with the strontium salt. The crystals are permanent in 
 the air, and do not give off any water over sulphuric acid ; they dissolve in 75 pts. 
 water at mean temperature. The salt begins to give off oxygen and bromine at 180 C., 
 a small quantity of brown peroxide of lead being formed at the same time, whereas at 
 a stronger heat, red lead or the yellow protoxide is formed ; the residue contains prot- 
 oxide with a small quantity of bromide. 
 
 BROMATE OF LITHIUM, LiBrO 3 , crystallises from a syrupy solution over sulphuric 
 acid, in needles, which effloresce in a dry atmosphere, but deliquesce when exposed to 
 the open air. 
 
 BROMATE OF MAGNESIUM. MgBrO 3 -f 3aq. Large regular octahedrons, which 
 dissolve in 1'4 pts. water at 15 C. ; melt in their water of crystallisation at a moderate 
 heat, give off the greater part of it at 200 C. ; and the last portion at a somewhat 
 higher temperature, oxygen being at the same time evolved. 
 
 BROMATE OF MANGANESE is formed by dissolving manganous oxide in bromic acid, 
 but decomposes very quickly. 
 
 BROMATES OF MERCURY. The mercuric salt, HgBrO 3 -f aq., is obtained by pouring 
 bromic acid on recently precipitated mercuric oxide, as a white powder, which dis- 
 solves in 600 pts. of cold and 64 pts. boiling water. It dissolves also in excess of warm 
 bromic acid, and crystallises in small prisms on cooling. Hydrochloric acid dissolves it 
 with decomposition. At 130 140 C. it decomposes with detonation, yielding a 
 sublimate of mercurous and mercuric bromide, and a residue of mercuric oxide ; but 
 giving off part of the bromine and oxygen as gas. Ammonia added to the warm 
 aqueous solution throws down a compound of mercuric bromate with oxide of dimercur- 
 ammonium, 2HgBr0 3 .(NH 2 Hg 2 ) 2 0, which does not yield any ammonia when treated 
 with potash. It is decomposed by heat with violent detonation. 
 
 Mercurous bromate, Hg 2 Br0 3 or HhgBrO 3 , is obtained as a white powder by preci- 
 pitation, or by completely saturating bromic acid with mercurous oxide. From a solu- 
 of the oxide in a slight excess of bromic acid, it separates by evaporation in shining 
 crystalline laminae. Water decomposes it, forming a basic salt, Hhg 2 0.2HhgBrO 3 . It 
 decomposes with detonation when heated. 
 
 BROMATE OF NICKEL. NiBrO 8 + 3aq. Green regular octahedrons having their 
 summits replaced by cube-faces. Thin plates cut parallel to the cube-faces act 
 strongly on polarised light (M arbach, Pogg. Ann. xciv. 412). The salt gives off water 
 when heated. It dissolves in 3'6 pts. of cold water, also in ammonia, and on adding 
 alcohol to the ammoniacal solution, a blue-green powder is precipitated, consisting of 
 ammonio-bromate of nickel, NH 3 .NiBr0 3 , or bromate of nickel-ammonium (NH 8 Ni)BrO s . 
 
 BROMATE OF PALLADIUM appears to be produced by dissolving palladous hydrate in 
 bromic acid. 
 
 BROMATE OF PLATINUM. Platinic sulphate decomposed by bromate of barium 
 yields a yellow filtrate, which, when evaporated, gives off oxygen and bromine-vapour, 
 and deposits platinic bromide. 
 
 BROMATE OF POTASSIUM. KBrO 3 . Prepared by adding bromine to a warm, 
 moderately concentrated solution of potash, till the liquid acquires a permanent yel- 
 lowish tint ; the salt then separates almost completely on cooling, and may be purified 
 from bromide of potassium by washing with water, and recrystallisation. It forms 
 
 scales, or sometimes in dendritic masses. According to Fritzsche, it always crystal- 
 
672 BROMIC ACID BROMIDES. 
 
 Uses in forms of the regular system; but, according to Rammelsberg, in rhombo- 
 hedrons, having the angles of the terminal edges = 86 18', and in forms derived 
 therefrom. It dissolves in 32'1 pts. water at 0C., in 18-5 pts. at 10, in 14-4 pts. at 
 20, in 7'5 pts. at 40, in 4-4 pts. at 60, in 2*9 pts. at 80, and in 2 pts. at 100 
 (Kremers, Pogg. Ann. xcii. 497; xciv. 255; xcvii. 1 ; xcix. 25, 58). According to 
 Pohl, 1 pt. of the salt dissolves in IT'S pts. water at 17 C. The crystals deposited 
 from a solution, either perfectly neutral or slightly acidulated with acetic acid, decre- 
 pitate with violence at 300 350 C., and crumble to a powder, which, if thrown 
 into water, gives off bubbles of pure oxygen gas as it dissolves ; but the solution when 
 evaporated yields nothing but pure bromate of potassium, probably reproduced by ab- 
 sorption of oxygen from the air. The crystals deposited from an alkaline solution 
 decrepitate but slightly when heated, and the powder dissolves in water without per- 
 ceptible evolution of gas. (Fritzsche, J. pr. Ch. xxiv. 285.) 
 
 Bromate of potassium is decomposed by strong sulphuric acid, with violent decre- 
 pitation and evolution of bromine and oxygen. When heated per se, it melts at a tem- 
 perature above 350 C., and then decomposes, with evolution of oxygen, slowly at first, 
 but afterwards with explosive violence, beginning to glow at one point, and then 
 quickly becoming incandescent through the entire mass. When mixed with combus- 
 tible bodies, it explodes with great violence when struck or heated. 
 
 BROMATE OF SELVER. AgBrO 3 . Obtained by precipitation as an amorphous white 
 powder quickly turning grey when exposed to light. According to Rammelsberg, it 
 forms shining quadratic prisms (P : P in the terminal edges = 121 587, in the lateral 
 edges = 86 38), isomorphous with chlorate of silver. When rapidly heated, it ex- 
 plodes with deflagration, giving off part of the bromine in the form of yellow vapour. 
 It dissolves sparingly in water and in nitric acid, more easily in ammonia, the solution 
 yielding by spontaneous evaporation, colourless prisms, which are quickly decomposed 
 by water, and are very unstable even in the dry state. 
 
 BROMATE OF STRONTIUM. 2SrBr0 3 + aq. Small shining rhomboi'dal prisms, with 
 truncated lateral edges, isomorphous with the barium-salt. Katio of axes = 
 1 : 1-1642 : 1-2292. Inclination of clino-diagonal to principal axis = 89. The 
 crystals dissolve in 3 pts. of water at ordinary temperatures ; do not lose weight over 
 sulphuric acid, become anhydrous at 120 C., and at a higher temperature are quickly 
 resolved into oxygen gas and bromide of strontium. 
 
 BROMATES OF TIN. Stannic hydrate unites slowly with bromic acid, and forms, 
 after drying over oil of vitriol, a vitreous mass, which loses 18 per cent, in weight at 
 180 C. Stannous chloride forms a white precipitate with bromate of potassium. 
 
 UHANIC BROMATE. A solution of uranic hydrate in bromic acid yields, by evapora- 
 tion over oil of vitriol, a yellow uncrystallisable syrup which decomposes by evapora- 
 tion, giving off bromine and leaving a basic salt. 
 
 BROMATE OF YTTRIUM. Sparingly soluble in water; remains in the anhydrous state 
 when its solution is evaporated. 
 
 BROMATE OF ZINC. ZnBr0 3 + 3aq. Regular octahedrons modified by cube-faces; 
 isomorphous with the magnesium-salt. It dissolves in 1 pt. water at ordinary tem- 
 peratures, is permanent in the air, melts in its water of crystallisation at 100 C., and 
 becomes anhydrous at 200, but undergoes decomposition at the same time, giving off 
 bromine-vapour and oxygen, and leaving pulverulent oxide of zinc. The salt is de- 
 composed by a small quantity of ammonia, but dissolves completely in excess of am- 
 monia, the solution yielding by evaporation over hydrate of potassium : 
 
 Ammonio-bromate of zinc, or bromate of zinc-ammonium, 2NH 3 ZnBr0 2 + 3 aq. in 
 small prismatic crystals, which, when exposed to the air, become moist and yellow, and 
 smell of free bromine. Water and alcohol decompose them with separation of hydrate 
 of zinc. At a gentle heat, the salt decomposes with a loud hissing noise, and gives off 
 bromine together with nitrogen gas and water. 
 
 BROIVTIC SILVER. Native bromide of silver. (See SILVER.) 
 BROMIDES. Compounds of bromine with electro-positive radicles. Bromine, 
 like chlorine, is monatomic, 1 at. of it being capable of uniting with 1 at. of hydrogen 
 or other monatomic radicle, 2 at. of bromine with 1 at. of a diatomic radicle, e.g. 
 bromide of ethylene (C 2 H 4 )"Br 2 , 3 at. of bromine with 1 at. of a triatomic radicle, e.g. 
 bromide of glyceryl (C 3 H 5 )'"Br 3 . Bromine is less powerfully electro-negative than 
 chlorine ; consequently bromides are for the most part decomposed by chlorine. 
 
 Bromide of Hydrogen. Hydrobromic or Brombydric Acid. HBr. This 
 compound is gaseous at ordinary temperatures, and is composed of equal measures of 
 bromine-vapour and hydrogen united without condensation. It is not readily formed 
 by the direct union of its elements. A mixture of hydrogen and bromine- vapour does 
 not unite when exposed to the sun's rays ; neither does it explode when a red-hot wire 
 
BROMIDE OF HYDROGEN. 673 
 
 or a li arm ng taper is introduced into it; but combination takes place slowly in the 
 immediate neighbourhood of the hot body, and more quickly when the mixture of 
 bromine and hydrogen is passed through a red-hot tube, or when a platinum wire im- 
 mersed in it is kept red-hot by the electric current. 
 
 Preparation. 1. By the action of water on tribromide of phosphorus : 
 PBr 3 + 3H 2 = H 3 P0 3 + 3HBr. 
 
 A few grammes of bromine are introduced into the bend a of the apparatus (fig. 113), 
 
 and in the bend b are placed some small pieces 
 
 of phosphorus, moistened with water, and sepa- 
 
 rated by pounded glass. The bromine at a is 
 
 gently heated by a spirit-lamp, and the vapour 
 
 passing over to b forms bromide of phosphorus, 
 
 which is immediately decomposed by the 
 
 water, yielding phosphorous acid, which re- 
 
 mains in the tube, and hydrobromic acid, 
 
 which passes on through the delivery-tube <?, 
 
 and may be collected over mercury. 2. By decomposing bromide of sodium or potas- 
 
 sium with strong sulphuric acid : 
 
 2NaBr + H 2 S0 4 = Na 2 S0 4 + 2HBr. 
 
 The hydrobromic acid thus produced is, however, mixed with vapour of bromine and sul- 
 phurous anhydride, produced in the manner represented by the equation : 
 
 2NaBr + 2H 2 S0 4 = 2Br + SO 2 + 2H 2 + Na 2 S0 4 ; 
 
 the bromine may be separated by agitation with mercury ; but the sulphurous anhy- 
 dride is not easily removed. 3. The aqueous solution of the acid may be prepared by 
 decomposing a solution of bromide of barium with sulphuric acid diluted with an equal 
 weight cf water, and distilling the filtered liquid. 4. Also by passing sulphuretted 
 hydrogen into a mixture of bromine and water : 
 
 lOBr + 2H 2 S + 4H*0 = lOHBr + H 2 S0 4 + S 
 
 The liquid is filtered to separate the precipitated sulphur, and the hydrobromic acid 
 separated from the sulphuric acid by distillation. 5. By the action of bromine on 
 hydriodic acid, on aqueous ammonia, and on many organic compounds, naphthalin, 
 for example. 
 
 Properties. Colourless gas having a very pungent odour, which excites coughing, 
 and a strongly acid taste. Reddens litmus strongly, and excites itching and inflam- 
 mation when applied to the skin. Fumes in the air more strongly than hydrochloric 
 
 acid. Specific gravity, by experiment, 271 (Lowig) ; by calculation - = 40*5, 
 
 compared with hydrogen, or 40'5 x 0-0693 = 2*801 compared with air. Liquefies 
 at -92 F. (-69 C.), and solidifies at -100 F. (-73 C.) (Faraday). It is 
 rapidly and copiously absorbed by water, forming a strongly acid solution, which, when 
 saturated, has a density of 1'29, and fumes strongly in the air. This saturated solu- 
 tion boils at a temperature below 100 C., giving off the gas, and is thereby rendered 
 weaker : a more dilute acid boils at a temperature above 100, and a very dilute acid 
 becomes stronger by boiling. 
 
 Decompositions. 1. The gas is not decomposed by heat alone. 2. Potassium intro- 
 duced into it, even at ordinary temperatures, decomposes it completely, forming bro- 
 mide of potassium, and leaving a volume of pure hydrogen equal to half that of the 
 original gas. Tin produces the same effect when aided by a gentle heat. This reac- 
 tion determines the composition of the acid ; for the weight of 1 vol. of the gas (the 
 observed specific gravity) diminished by the weight of half a volume of hydrogen, 
 gives a number which is very nearly half the observed specific gravity of bromine 
 (5'54 according to Mitscherlich) : 
 
 Hence the gas is composed of equal volumes of bromine and hydrogen, united without 
 condensation. 3. The gas, or its aqueous solution, is immediately decomposed by 
 chlorine, hydrochloric acid being formed and bromine separated, recognisable by its 
 red colour. Iodine, on the contrary, does not decompose hydrobromic acid. Hence 
 the affinity of bromine for hydrogen is, under similar circumstances, less than that of 
 chlorine, and greater than that of iodine. 4. The acid is also decomposed by oxygen 
 and by highly oxidised bodies. The aqueous solution turns brown on exposure to the 
 air, from separation of bromine, which remains dissolved. Nitric acid also separates 
 VOL. I. XX 
 
674 BROMIDES. 
 
 the bromine, especially on heating the liquid. The mixture of" the two acids dissolves 
 gold, like nitrohydrochloric acid. Strong sulphuric acid decomposes it, yielding sul- 
 phurous anhydride, bromine, and water : 
 
 H 2 SO + 2HBr = SO 2 + 2H 2 + Br 2 . 
 With bromic acid, it yields water and free bromine : 
 
 HBrO 3 + 5HBr = 3H 2 + Br 6 . 
 
 5. With metallic protoxides, it forms water and a bromide of the metal : e. g. 
 2HBr + Ag 2 = 2AgBr + H 2 0. With peroxides, a similar decomposition takes place, 
 attended also with evolution of bromine: e.g. 2HBr + MnO = MnBr + H 2 + Br. 
 
 Combinations. Hydrobromic acid unites directly with ammonia NH 3 , forming 
 hydrobromate of ammonia, NH 3 .HBr, or bromide of ammonium, NH 4 Br. Similarly 
 with the compound ammonias, methylamine, cthylamine, &c., and with phosphor ctttd 
 hydrogen. The aqueous solution dissolves certain metallic oxides, viz. the alkalis and 
 earths, forming solutions, which may be supposed to contain hydrobro mates of 
 those oxides. It unites with many hydrocarbons, e. g. with oil of turpentine, forming 
 the compound C 10 H 16 .HBr. 
 
 Bromides, Metallic. MBr. Bromine unites directly with most metals. Po- 
 tassium, arsenic, antimony, and tin unite with liquid bromine, producing vivid com- 
 bustion ; bismuth, iron, and mercury combine with it at ordinary temperatures 
 without combustion ; but on the application of heat, combustion takes place. Gold 
 combines gradually with bromine at ordinary temperatures ; platinum does not. With 
 many metals, the application of heat is necessary to induce combustion. Bromides are 
 also formed by the action of metals on hydrobromic acid gas (p. 672). Vapour of 
 bromine passed over ignited potash, soda, baryta, or lime, forms a bromide of the 
 metal and eliminates the oxygen ; bromine decomposes oxide of silver, even at ordi- 
 nary temperatures. Carbonates are also readily decomposed by it. 
 
 Nearly all bromides are soluble in water ; bromide of lead however dissolves very spar- 
 ingly, and bromide of silver and mercurous bromide are quite insoluble. The soluble 
 bromides may all be produced by the action of hydrobromic acid on the corresponding 
 oxides or carbonates ; and on evaporating the solutions, water is in most cases given 
 off, the metallic bromide remaining. Some of them, however, viz. the bromides of 
 magnesium, aluminium, and the other earth-metals, are more or less decomposed 
 during the evaporation of the solutions, giving off hydrobromic acid and leaving a 
 mixture of bromide and oxide of the metal. 
 
 Metallic bromides are solid at ordinary temperatures ; most of them fuse at a 
 moderate heat, and volatilise at higher temperatures. They strongly resemble the 
 chlorides. The bromides of gold and platinum are decomposed by mere exposure to 
 heat ; many others give up their bromine when heated in contact with the air. Chlo- 
 rine, with the aid of heat, drives out the bromine and converts them into chlorides. 
 Hydrochloric acid also decomposes them at a red heat, giving off hydrobromic acid. 
 Strong sulphuric or nitric acid decomposes them, with evolution of hydrobromic acid, 
 which, if the sulphuric or nitric acid is concentrated and in excess, is partly decom- 
 posed, with separation of bromine and formation of sulphurous anhydride or nitric 
 oxide (p. 672). Bromides heated with sulphuric acid and peroxide of manganese or 
 chromate of potassium, give off free bromine. If the bromide is quite pure, the 
 evolved bromine is completely decolorised by ammonia; but if chlorine is also present, 
 cholorochromic acid distils over, together with the bromine, and the distillate then 
 forms a yellow liquid with ammonia. 
 
 Bromides in solution are easily decomposed by chlorine, either in the form of gas 
 or dissolved in water, the liquid acquiring a red or reddish-yellow colour, according to 
 the quantity of bromine present ; and on agitating the liquid with ether, that liquid 
 dissolves the bromine, forming a red solution, which rises to the surface. (See BRO- 
 MINE. 
 
 Soluble bromides give with nitrate of silver, a white precipitate of bromide of silver, 
 greatly resembling the chloride, but much less soluble in ammonia ; insoluble in hot 
 nitric acid. Mercurous nitrate produces a yellowish- white precipitate ; and acetate of 
 lead, a white precipitate much less soluble in water than the chloride. Nitrate of pal- 
 ladium produces in solutions of bromides not containing chlorine, a black precipitate 
 of bromide. Chloride of palladium produces no precipitate ; neither does the nitrate, 
 if soluble chlorides are present. 
 
 Bromides of Organic Radicles. Bromine unites with organic radicles both basic 
 and acid. The compounds are formed in the same manner as the corresponding 
 chlorides, which they also resemble in most of their properties, though they aro 
 less volatile. They contain, in two volumes of vapour, one, two, or three volumes of 
 
BROMIDES BROMINE. 675 
 
 bromine- vapour, according as the organic radicle which they contain is mono-, di-, or 
 
 tri-atomic, e. g. : 
 
 2 voL bromide of trityl C 3 H 7 Br contain 1 vol. bromine 
 tritylene (C 3 H 6 )"Br 2 2vol. 
 glyceryl (0H 5 )'"Br 3vol. 
 
 1. The bromides of the alcohol-radicles, hydrobromic or bromhydric ethers, are 
 obtained by distilling the corresponding alcohols with hydrobromic acid or bromide of 
 phosphorus: e.g. : 
 
 C 2 H 5 .H.O + PBr 5 = C 2 H 5 Br + HBr + PBr 3 
 
 Alcohol. Bromide Oxybro- 
 
 of ethyl. mide of 
 
 phosphorus. 
 
 Distilled with alkalis, they yield the corresponding alcohol and a bromide of the 
 alkali-metal. 
 
 2. The bromides of acid-radicles are produced by the action of bromide of phosphorus 
 on the corresponding acids, or by the action of chlorides of acid-radicles on certain 
 metallic bromides : e. g. bromide of acetyl, C 2 H 3 O.Br ; bromide of succinyl, (C*H 4 2 )"Br 2 . 
 Alkalis decompose them, with formation of a metallic bromide, and a salt of the cor- 
 responding organic acid, e.g. : 
 
 (C 4 H 4 2 )"Br 2 + 2KHO = C 4 H 4 2 .K 2 .0 2 + KBr. 
 Bromide of Succinate of 
 
 succinyl. potassium. 
 
 3. The bromides of aldehyde-radicles are monatomic bromides of the general form, 
 (jnjpn-ijjr : e.g. bromide of vinyl, C 2 H 3 Br. They are isomeric with the monobromi- 
 
 nated diatomic alcohol-radicles, e.g. C 3 H 5 Br, with bromotritylene, C 3 -g . They are 
 
 volatile liquids, obtained by the action of alcoholic potash on the bromides of the 
 diatomic alcohol-radicles : their properties and reactions are analogous to those of the 
 corresponding chlorides (q. r.) 
 
 4. Many other organic radicles, such as oil of turpentine, its isomers and homo- 
 logues, likewise unite with bromine and with hydrobromic acid, forming definite com- 
 pounds, sometimes liquid, sometimes crystalline, e.g. bromide of cajputene, C 10 H 1G Br 4 ; 
 hydrobromate of turpentine-oil, C 10 H 16 .HBr, &c. 
 
 BROMEXNTDAXVIXTX*. See the next article. 
 
 BROMXWDOPTJSXirE. The name of a doubtful compound, which Erdmann ob- 
 tained, together with bromisatin and dibromisatin, by the action of bromine on indigo. 
 It was resolved by potash into bromindoptic (bromophenissic) acid, and a volatile 
 body, called by Erdmann bromindamite, but doubtless identical with tribromo- 
 phenylamine. (Handw. d. Chem. l te Aufl. iv. 22.) 
 
 BROMINE. Symbol Br. Atomic weight 80. This element was discovered in 
 1826 by Balard, who extracted it from the mother-liquor of the salt-marshes of Mont- 
 pellier. It exists in sea- water ; in the water of many salt-springs, especially in that 
 of Theodorshall, near Kreuznach in Prussia, whence a large portion of the bromine of 
 commerce is obtained ; and, together with iodine, in the ash of sea-weed (soude de 
 varech), whence larger quantities are extracted; also in sponges and many marine 
 animals. As bromide of silver, it is found native in Mexico and Chili, and at Huel- 
 goeth in Bretagne ; very small quantities are found in Silesian zinc-ore and in English 
 rock-salt. 
 
 Preparation. 1. From the mother-liquor of sea-water or saline-springs. After these 
 waters have been freed by crystallisation from the greater part of the chlorides and 
 sulphates of sodium and potassium, the remaining liquid contains bromine, chiefly in 
 the form of bromide of magnesium. This liquid is mixed in a retort with peroxide of 
 manganese and hydrochloric acid, and distilled. Chlorine is then evolved in the liquid, 
 and decomposes the bromide of magnesium, setting free the bromine, which distils 
 over into the receiver, in the form of a heavy dark-red liquid, surmounted by ati 
 aqueous solution of bromine. 2. From the mother-liquor of varcc. This liquid con- 
 tains iodine and bromine, in the proportion of about 1 pt. bromine to 8 iodine. The 
 iodine is first precipitated either by passing chlorine gas into the liquid, till a sample 
 taken out gives no precipitate either with chlorine-water or with iodide of potassium ; 
 or it is precipitated as free iodine and cuprous iodide, by adding cupric sulphate to the 
 liquid : (Cu 2 S0 4 + 2NaI = Na 2 S0 4 + Cu 2 I + I). The remaining liquid is then mixed 
 with peroxide of manganese and strong sulphuric acid (the requisite proportions being 
 
 xx 2 
 
676 BROMINE. 
 
 first determined by trial on a small quantity) and distilled. The "bromine then passes 
 over as before, the decomposition being effected in the manner shown by the equation : 
 
 2MgBr + 2MnO + 2IFS0 4 = Br 2 + Mg 2 S0 4 + Mn'SO 4 + 2H 8 0. 
 
 The bromine which collects at the bottom of the receiver in either mode of preparation, 
 is separated from the supersaturated aqueous solution by means of a tap-funnel, and 
 further purified by distillation in contact with chloride of calcium. The aqueous 
 solution is shaken up with ether ; the red ethereal solution of bromine which rises to 
 the top is treated with caustic potash, till its colour disappears, whereby bromide and 
 bromate of potassium are produced ; the liquid is evaporated to dryness ; and the 
 residue is ignited in a crucible, to convert the bromate KBrO s , into bromide KBr. 
 The whole quantity thus obtained is decomposed by distillation with peroxide of man- 
 ganese and sulphuric acid, whereby the remaining quantity of bromine is obtained in 
 the free state. 
 
 Commercial bromine is generally contaminated with chlorine, derived either from 
 that which is used to separate it, or from the mother-liquor itself. It may be purified 
 by saturating it with hydrate of barium, whereby bromide, chloride, bromate, and 
 hypochlorite of barium are formed ; evaporating and igniting to decompose the oxygen- 
 salts ; and treating the residue with alcohol, which dissolves the bromide of barium 
 and leaves the chloride. The pure bromide is then decomposed with sulphuric acid 
 and peroxide of manganese, as above. 
 
 Properties. Bromine is, at ordinary temperatures, a liquid of a deep brown-red colour. 
 It has a peculiar irritating, disagreeable odour ; whence its name (/Spw/ios), and a re- 
 pulsive taste. It is highly poisonous ; a drop placed on the beak of a bird is sufficient 
 to destroy life. Specific gravity 2-966 (Balard) ; between 2-98 and 2-99 at 15 C. 
 (Lowig) ; 3-1872 at C. (Pierre). It is a non-conductor of electricity. At 22 C. 
 it solidifies, forming a hard, brittle, laminated mass, having a dark lead-grey colour, 
 and semi-metallic lustre: it retains the solid state for a long time, even at 12 C. 
 It is very volatile ; a few drops thrown into a large flask speedily fill it with red 
 vapours. It boils at 63 C. (Pierre); at 58 (Andrews); at 45 (Lowig). Vapour- 
 density 5'54: (Mitscherlich) ; by calculation, 80 compared with hydrogen; 5'544 
 ( = 80 x 0'0693), compared with air. 
 
 Bromine dissolves sparingly in water, more readily in alcohol, and in all proportions 
 in ether. With water at C. it forms a solid hydrate, Br . 5H 2 0, which is not decom- 
 posed between 15 and 20. 
 
 Bromine resembles chlorine in many of its properties. It has a powerful affinity for 
 hydrogen, though not quite so strong as that of chlorine, and hence it acts with energy 
 upon many organic substances. It is a powerful bleaching agent, and corrodes wood 
 and cork, first turning them yellow. A small quantity of it imparts a transient yel- 
 low colour to the skin ; a larger quantity stains it permanently yellow, then brown, 
 and a still larger quantity produces immediate corrosion and violent inflammation. It 
 colours starch orange-yellow. It decomposes vapour of water when passed with it 
 through a tube heated t bright redness, yielding hydrobromic acid and cxvgen. A 
 burning taper introduced into vapour of bromine, burns for an instant with a green 
 light, and is then extinguished. 
 
 Bromine decomposes phosphoretted hydrogen, sulphydric acid, hydriodic acid, and 
 metallic iodides, but the resulting bromine-compounds are decomposed by chlorine. 
 
 Bromine acts readily on many organic compounds, removing part of the hydrogen 
 in the form of hydrobromic acid, while another portion of bromine takes the place of 
 the hydrogen thus abstracted, 80 pts. bromine being always introduced for every 
 1 pt. of hydrogen removed. In this manner, bromacetic acid, C 2 H 3 Br0 2 , and a con- 
 siderable number of other brominated compounds, are formed. 
 
 Bromine unites with all the elementary bodies, and with many compound radicles. 
 In all its compounds, except those with chlorine, fluorine, oxygen, and perhaps sul- 
 phur, it plays the part of the chlorous or electro-negative element. In this respect, 
 it is intermediate between chlorine and iodine, expelling the latter from its combina- 
 tions with positive radicles, and being itself expelled by the former (see BROMIDES, 
 p. 672). We shall here describe only those compounds in which the bromine is 
 electro-positive, viz. the chlorine, fluorine, oxygen, and sulphur-compounds : the others 
 are described under the several positive radicles. 
 
 BROMINE, CHXiORXDE OP. Bromine absorbs a large quantity of chlorine 
 gas, forming a reddish-yellow, mobile liquid, very volatile, and giving off dark -yellow, 
 strong-smelling, and tear-exciting vapours, which exert a powerful bleaching action, 
 and in which metals burn quickly to chloride and bromide. 
 
 When chloride of bromine is mixed with a small quantity of water, and cooled to 
 C., or when gaseous chloride of bromine is passed through a glass tube moistened 
 
BROMINE : DETECTION AND ESTIMATION. 677 
 
 with water, the hydrated chloride of bromine is formed, which crystallises in 
 needles or laminae, and melts at 7 C. to a light yellow liquid. It is decomposed by 
 ammonia, forming nitrogen gas, chloride of nitrogen, and bromide of ammonium. 
 Chloride of bromine dissolves with yellow colour in water. The same solution is ob- 
 tained by dissolving bromine in saturated chlorine- water ; it has the odour and bleach- 
 ing action of chloride of bromine ; decomposes in sunshine into hydrochloric and 
 bromic acids, and is decomposed in like manner by aqueous alkalis, yielding a chloride 
 and a bromate of the alkali-metal. The aqueous solution is decomposed by ether, 
 which separates and dissolves the bromine. (Handw. d. Chem. ii. [2] 475.) 
 
 BROMINE, DETECTION AND ESTIMATION OP. 1. Reactions. 
 Free bromine is recognised by its odour, the deep-red colour of its vapour, and the 
 orange-yellow colour which it imparts to gelatinous starch. When it exists in aqueous 
 solution in too small quantity to be recognised immediately, it may be separated by 
 shaking up the liquid with ether, and proceeding as described below. 
 
 Bromine in the state of hydrobromic acid or a soluble metallic bromide, is detected 
 by the reactions already described (pp. 672, 673). Small quantities of bromine are most 
 easily recognised by cautiously adding chlorine-water till the solution assumes a red 
 or yellow tint ; if too much chlorine be added, chloride of bromine will be formed, 
 which is colourless. On shaking the solution with ether, that liquid dissolves the 
 bromine, and rises to the surface in the form of a red stratum. This may be separated 
 by a pipette, or ta,p-funnel ; neutralised with potash, which decolorises it, converting 
 the bromine into bromide and bromate of potassium ; and evaporated to dryness in 
 a porcelain crucible. On igniting the residue, to convert it all into bromide, then intro- 
 ducing it into a test-tube, and heating with sulphuric acid and peroxide of manganese, 
 bromine is given off in red vapours, which, if led into a solution of starch, colour it 
 orange-yellow. 
 
 The presence of chlorides does not interfere with this reaction ; if, however, the 
 quantity of chlorine is very large compared with that of the bromine, as in saline 
 waters, it is best to concentrate the solution till the greater part of the chlorides crys- 
 tallise out, and search for bromine in the mother-liquor. If iodine is present, it must 
 first be removed, either by precipitation with chloride of palladium, or by first adding 
 just suiScient chlorine-water to precipitate the iodine, which is sure to be set free 
 before the bromine : in fact, bromine itself separates iodine from its compounds ; 
 but the removal of the iodine is absolutely necessary, as its deep violet vapour 
 would disguise the colour of the bromine, unless the quantity of the latter greatly 
 predominated. 
 
 The methods of decomposing insoluble bromides mil be given further on ; likewise 
 the methods of separating bromine from phosphorus, and other non-metallic elements. 
 Bromates are reduced to bromides, either by ignition or by treatment with sulphurous 
 or sulphydric acid. 
 
 2. Quantitative Estimation. When bromine is present in a solution in the 
 form of a bromide, it may be precipitated by nitrate of silver, the precipitate of 
 bromide of silver being ignited in a porcelain crucible, with the same precautions as 
 the chloride (see CHLORINE). It contains 42-55 per cent, bromine. If the solution is 
 alkaline, it must be acidulated with nitric acid, added after the precipitation by 
 nitrate of silver ; if it were added before, a portion of the bromine might be set free 
 and lost. 
 
 Insoluble bromides, e.g. bromide of lead, and cuprous bromide, may be decomposed 
 by suspending them in water, and passing sulphuretted hydrogen through the liquid. 
 The metal is then converted into sulphide, while hydrobromic acid remains dissolved 
 
 by precipitation with nitrate of silver. Bromide of silver may 
 also be decomposed by fusion with carbonate of sodium, or, better, with a mixture of 
 carbonate of sodium and carbonate of potassium in equivalent proportion, in a porcelain 
 crucible. The silver is thereby reduced to the metallic state, and may be weighed 
 after washing. The bromine is then estimated by loss. 
 
 Another method of decomposing bromide of silver, is to treat it with dilute sul- 
 phuric acid and pure metallic zinc. The silver is then reduced by the nascent hydrogen, 
 and the bromine passes into the solution as bi-omide of zinc. The silver may then be 
 washed and weighed as before. This method, however, is not quite exact (see 
 CHLORINE). Mercurous bromide may be completely decomposed by a solution of pure 
 caustic potash, a solution of bromide of potassium being formed, from which the 
 bromine may be precipitated by nitrate of silver with addition of nitric acid. 
 
 Many oxybromides which are insoluble in water, are soluble in nitric acid. The 
 acid should be dilute, and if heat is required, the materials must be placed in a flask 
 
 x x 3 
 
678 BROMINE: ESTIMATION. 
 
 having a glass stopper, and the heat kept as low as possible, otherwise bromine will 
 escape. The bromine may then be thrown down as bromide of silver. 
 
 Volatile bromides, such as the bromides of sulphur, phosphorus, arsenic, and anti- 
 mony, are completely decomposed by water, the bromine being converted into hydro- 
 bromic acid, from which it may be precipitated by nitrate of silver. 
 
 Bromates must be reduced to bromides by sulphurous or sulphydric acid ; the 
 bromine may then be precipitated by silver-solution, after the excess of the reducing 
 agent has been removed by a ferric salt. Bromates may also be converted into bromides 
 by ignition. 
 
 The quantity of free bromine in a solution, is estimated by treating it with excess of 
 ammonia, whereby it is completely converted into bromide of ammonium, with evo- 
 lution of nitrogen. The diluted solution is then treated with nitrate of silver. 
 
 Estimation of Bromine in presence of Chlorine. There is no known method of 
 effecting a complete separation of these elements, and when they occur together, their 
 amounts must be estimated by an indirect method. This is effected by precipitating 
 them, both together by nitrate of silver ; fusing and weighing the entire precipitate 
 in a porcelain crucible ; then remelting it ; taking out a convenient portion on the 
 end of a glass rod ; cutting it when cold into small shavings ; introducing them in- 
 to a bulb-tube ; and igniting them, after weighing, in a current of dry chlorine. The 
 whole of the bromine is then expelled, provided the stream of chlorine is kept up 
 for some time, and nothing but chloride of silver remains. This is weighed, and from 
 its weight, and that of the mixture of chloride and bromide before decomposition, the 
 quantities of chlorine and bromine may be found. For the difference of the weights 
 (d) is clearly the difference between the weight of the bromine expelled and that of 
 the chlorine which has taken its place ; and for every 80 pts. of bromine expelled 
 3 5 -5 pts. of chlorine have come in : hence we have the equations : 
 
 80 
 whence: Br = d = 1796* 
 
 that is to say : to find the quantity of bromine, multiply the difference, of the weights 
 by 1796. 
 
 If the quantity of bromine is very small compared with the chlorine, this method 
 does not give exact results. In that case, it is necessary to concentrate the bromine, 
 that is, to increase the proportion of it in the precipitate subjected to the experiment. 
 Now when a mixture containing a large quantity of soluble chloride with a small pro- 
 portion of bromide, is treated with about one-sixth of the quantity of nitrate of silver 
 required for complete precipitation, the whole of the bromine is precipitated, together 
 with a portion of the chlorine. The liquid must be briskly agitated to cause the 
 precipitate to settle down, but no heat must be applied. The precipitate is then to 
 be ignited, weighed, and decomposed in a stream of chlorine in the manner just de- 
 scribed. The remainder of the chlorine, now free from bromine, is precipitated as 
 chloride of silver in the usual way. Another method of concentrating the bromine in 
 a mixture of chloride of sodium containing a small quantity of bromide, is to treat 
 the dry mixture with very strong alcohol, which dissolves the whole of the bromide of 
 sodium, but only a small portion of the chloride. The filtered alcoholic solution is 
 then evaporated, the residue is dissolved in water, and the bromine and chlorine are 
 precipitated by nitrate of silver and estimated as before. To estimate the quantity 
 of bromine in sea- water or a brine-spring, the liquid must be evaporated to dryness, a 
 weighed quantity of carbonate of sodium having been preA r iously added to prevent the 
 loss of bromine and chlorine which might arise from the decomposition of the chloride 
 and bromide of magnesium during the evaporation, and the dry residue treated with 
 alcohol as above. 
 
 Estimation of Bromine in presence of Iodine. The iodine is precipitated by chloride 
 of palladium (or by the nitrate, if chlorides are present, p. 674), the excess of pal- 
 ladium removed by sulphuretted hydrogen, the excess of this last reagent by nitric 
 acid or a ferric salt, and the bromine then precipitated by nitrate of silver. 
 
 (For other modes of estimation, see CHLORINE and IODINE.) 
 
 Field (Chem. Soc. Qu. J. x. 234) has shown that chloride of silver is completely 
 decomposed by digestion with solution of bromide of potassium, the chlorine and 
 bromine changing places ; and that both bromide and chloride of silver are decomposed 
 in like manner by iodide of potassium. Hence, if a solution containing chlorine, 
 iodine, and bromine, be divided into three equal parts ; ouch portion precipitated by 
 nitrate of silver; the first precipitate dried and weighed; the second digested with 
 bromide of potassium, then dried and weighed ; and the third with iodide of potas- 
 
BROMINE: FLUORIDE. 679 
 
 sium, then dried and weighed, the relative quantities of the three elements may be 
 determined by an extension of the method of calculation above given (see also p. 224). 
 Let the weights of the three precipitates be w, w', and w" ; also let the atomic weights 
 of chloride, bromide, and iodide of silver be c, b, and i respectively, and the unknown 
 quantities of chloride, bromide, and iodide of silver, x, y, and z ; then we have the 
 three equations : 
 
 x + y + z = w 
 
 - x + y + z = w' 
 c 
 
 i i 
 
 x + -,y + z = w 
 c b 
 
 The first and second give : x = -^-y 
 
 Substituting this value in the second and third, they become: 
 
 b(w w') r n 
 y + z = w !_ -L [= p] 
 
 whence : 
 
 and: z = w (x + y}. 
 
 For the volumetric estimation of bromine, see ANALYSIS, VOLUMETRIC (p. 267). For 
 the estimation of bromine in organic compounds, see ANALYSIS, ORGANIC (p. 247). 
 
 3 . Atomic We ig Jit of Bro m i n e. The older determinations of the atomic weight 
 of bromine were much too low. Balard estimated it at 75'8, Liebig at 75-2, BerzeKus 
 at 78*2. The most exact determinations are due to Marignac (Biblioth. univ. de 
 Geneve, xlvi. 357), who found: 1. That 100 pts. pure silver dissolved in nitric acid 
 and precipitated by bromide of potassium, yielded, as a mean, 174*065 pts. bromide of 
 silver ; whence, the atomic weight of silver being 108, that of bromine is x = 74*065 x 
 
 108 
 
 . = 79-91. 2. That 100 pts. silver required for precipitation, HO'36 pts. bromide 
 
 100 
 
 of potassium; whence if Ag = 108 and K = 39'1, we have 100 : 110*36 = 108 : 
 
 39-1 + x; whence x = 80'09. 3. That 100 pts. bromate of potassium give off by 
 
 ignition, on the average, 29723 pts. oxygen, whence Br = 79'97. The mean of all 
 
 these results is very nearly Br = 80, which is the number now universally adopted. 
 
 Dumas arrived at the same result by igniting bromide of silver in chlorine gas, and 
 
 determining the difference of weight thereby produced. 
 
 BROMINE, FLUORIDE OP. Fluorine is readily absorbed by bromine. The 
 resulting compound, according to Leesen (Phil. Mag. Dec. 1844, p. 520) is liquid, 
 easily soluble in water, and does not sensibly attack glass. It has been used as a 
 means of accelerating the taking of photographic pictures by the electric light. (Compt. 
 rend, xxxiii. 501.) 
 
 BROMINE, OXYGEN-ACIDS OP. The series of oxygen- compounds of bro- 
 mine is by no means so complete as that of chlorine. No anhydrous oxide of bromine 
 is known, and of the acids, only one has been obtained in the separate state and 
 thoroughly examined, viz. Bromic acid, HBrO 3 , already described (p. 669). All 
 attempts to prepare a perbromic acid, analogous to perchloric acid, HC10 4 , have boen 
 unsuccessful; but the existence of hypobromous acid, HBrO, is rendered probable 
 by many experiments, though neither the acid itself, nor any of its salts, have yet 
 been obtained in definite form. 
 
 When mercuric oxide is added to bromine-water, a sparingly soluble oxybromide of 
 mercury is formed, together with a bleaching liquid, which, by distillation in vacuo, 
 yields a liquid supposed to be hypobromous acid (Balard). According to Gray-Lussac, 
 hypobromous anhydride may be obtained in the gaseous state in the same manner as 
 hypochlorous anhydride. (See CHLORINE, OXIDES or.) 
 
 When bromine is added to cold dilute aqueous alkalis, a metallic bromide is formed, 
 together with a very small quantity of bromate, and a liquid, which does not smell of 
 bromine, bleaches litmus and indigo and vegetable colours in general, and gives off 
 nitrogen in contact with ammonia. On heating the liquid, no bromine is evolved, but 
 a bromate is formed and the bleaching power is destroyed. These phenomena are 
 precisely analogous to those which are exhibited when chlorine is dissolved in cold 
 alkaline solutions. (See HYPOBROMOUS ACID.) 
 
680 BROMIODOFORM BRONZITE. 
 
 BROMINE, SELEWIDE OF. See SELENIUM, BROMIDE OF. 
 
 BROMINE, SULPHIDE OP. When bromine is brought in contact with 
 flowers of sulphur at ordinary temperatures, a dark brown, fuming, oily liquid is formed, 
 having an odour like that of sulphide of chlorine. It is not altered by cold water ; 
 but water at 10 C. decomposes it with slight explosion, forming sulphuric, hydro- 
 bromic, and sulphydric acids. When it is distilled, the first third of the distillate 
 appears to consist of Br 3 S 2 , while the liquid remaining in the retort is a mixture of 
 this compound with another sulphide of bromine, and, even when the distillation is 
 completed, there still remains a viscid liquid containing bromine. (H. Rose, Pogg. 
 Ann. xxviii. 550.) 
 
 BRO1VEXODOFOR1VX. CHBr 2 !. This compound is produced by treating iodo- 
 form with bromine. It is a colourless liquid, which solidifies to a camphorated mass 
 at C. ; melts at + 6 ; is very volatile ; has a penetrating odour and saccharine taste. 
 It maybe regarded as dibrominated iodide of methyl. (Serullas, Ann. Ch. Phys. 
 [2] xxxiv. 225 ; xxxix. 97. Bouchardat, J. Pharm. xxiii. 10.) 
 
 BROTCISATXC ACID. See ISATIC AdD. 
 
 BROIVEISATIN. See ISATIN. 
 
 BROMITE. Native bromide of silver, found in Mexico and in Chili. (See SILVER, 
 BROMIDE OF.) 
 
 BROIVXXTOXTXC ACXX). See CiTEACONic ACID, DECOMPOSITIONS OF. 
 
 BROIKXiXTE. Syn. with ALSTONITE. 
 
 BROMO-COlKPOintirilS or BROIKXNATED COMPOUNDS. Compounds 
 resulting from the substitution of bromine for hydrogen, chiefly in organic bodies. 
 They are produced by the action of bromine or of bromide of phosphorus on alcohols, 
 acids, hydrocarbons, &c. Most of them are described under the several principal 
 compounds, e. g. BROMOBRUCINE under BRUCINE, &c. 
 
 BROXKOFORIK. CHBr 3 . Produced by the simultaneous action of bromine 
 and caustic potash on wood-spirit, alcohol, or acetone ; also by the action of bromine 
 on aqueous citric or malic acid ; and by decomposing bromal with alkalis. It is a 
 limpid liquid of specific gravity 2*13, having an agreeable odour and saccharine taste. 
 It is less volatile than chloroform, very little soluble in water, to which, however, it 
 imparts its taste and odour ; soluble in alcohol, ether, and essential oils. It dissolves 
 small quantities of sulphur and phosphorus, and a large quantity of iodine. It burns 
 with difficulty. When its vapour is passed through a red-hot tube, it is resolved into 
 charcoal and bromine-vapour. Boiling potash-ley decomposes it more easily than 
 chloroform, yielding formate and bromide of potassium. (Lo'wig, Ann. Ch. Pharm. 
 iii. 295. Dumas, Ann. Ch. Phys. [2] Ivi. 120.) 
 
 BROXWOPXCRXN. CBr 3 N0 8 . A product obtained by distilling picric acid with 
 hypobromite of calcium (p. 923). 
 
 BROXraoSABXXDE. See SALICYLAMIDE. 
 
 BROlVfOTRXCONXC ACID. ) See CITRIC AND CITRACONIC ACIDS, Decompo- 
 BROXVIOXAFORXK. \ sitions by bromine. 
 
 BROMITS. A genus of grasses. The ashes of Bromus erectus and Bromus mottis 
 have been analysed by Way and Ogston (Journal of the Eoyal Agr. Soc. [2] xii. 
 530). 100 pts. of Br. erectus (air-dried) yielded 596 per cent, water, and 2-1 ash; of 
 Br. mollis, 1 6 '6 per cent, water and 1-4 ash. 
 100 pts. of ash were found to contain : 
 
 K2Q Na2Q Ca2Q Mg2Q Fe4Q3 SO* SiQ2 . CO* P2O KC1 NaCl 
 Br. erectus. . 20'3 .. 104 5-0 026 6'5 38'5 0-5 7'5 10'6 1-4 
 Br. mollis . . 3<M 0-3 6'6 2-6 0-21 4-9 33'3 9'1 9-6 .. 3'1 
 
 BROnrSTRXTE. Native bromide of silver. See SILVER. 
 
 BRONZE. An alloy of copper and tin. See COPPER. 
 
 BRONZITE. Schillcrspar. Diallage fibro-laminaire. A mineral belonging to 
 the augite family (p. 476). It is massive, with laminar structure inclining to fibrous. 
 Colour varying from yellowish-brown to pinchbeck-brown. Lustre from mother-of- 
 pearl to bright adamantine (pseudo-metallic). Harder than felspar. Specific gravity 
 3'201 to 3-25. Like all the augites, it is a metasilicate, its general formula being 
 M 2 Si0 3 or M 2 O.Si0 2 , the M 2 denoting lime, magnesia, manganous oxide, and ferrous 
 oxide in variable proportions, the magnesia, however, predominating. It is found in 
 large masses in beds of serpentine. 
 
 Delesse examined a mineral from the serpentine of IIoux in the Vosges, which 
 resembled bronzite in its large amount of magnesia (56-33 Si 2 0; T50 Mn 4 3 and 
 Cr 4 s ; 673 Fe'O; 31'93 Mg 2 0; 1'40 Ca 2 0; 2'11 Joss by ignition); but differed from 
 
BROOKITE BRUCINE. 68 1 
 
 it in not possessing the same metallic lustre and pinchbeck-brown colour, and in being 
 less distinctly cleavable, especially parallel to oP; specific gravity 3 '154 (Ann. Min. 
 [4] xviii. 318). (For other analyses of bronzite, see G-m. Handb. iii. 403, 404; 
 G-arrett, Sill. Am. J. [2] xv. 333; Kjerulf, Bischofs Lehrb. d. chem. u. phys. 
 Geolog. ii. 1495.) 
 
 BROOKITE. Jurinite. Arkansite. One of the forms of native titanic anhydride 
 TiO 2 , which is trimorphous. The crystals belong to the trimetric system, and generally 
 exhibit very complicated combinations, among which we may assume, as the primary 
 form, the pyramid P, in which the lengths of the brachydiagonal, macrodiagorial, and 
 principal axis, are to one another, as 0'5951 : 1 : 0'5558. Angle of the terminal edges 
 in the brachydiagonal section = 135 46' ; in the macrodiagonal section = 101 37' ; 
 and of the lateral edges = 94 44. The crystals exhibit, together with P, the faces 
 oo Poo and oo P 2, likewise other pyramids and horizontal ^prisms ; and are often 
 reduced to the tabular form by predominance of the faces oo P oo. Cleavage parallel 
 to oo P oo. Yellow, red, brown, or black, with adamantine or semi-metallic lustre. 
 Transparent to opaque. Streak yellowish- white. Hardness = 5 - 5 to 6*0. Specific 
 gravity = 3'85 to 4*22. Brittle. It is found at Oisaus in Dauphine, at Tremadoc in 
 Wales, on the St. Gothard, in the Valorsina and the Grisernthal in Switzerland, at 
 Miask in the Ural, and at Magnet Cove in Arkansas. The crystals from the last- 
 mentioned locality, were at first regarded as a distinct species, called Arkansite. (K o pp, 
 Handw. d. Chem. ii. [2] 521 ; Krystallographie, p. 256.) 
 
 BROS SITE. A variety of bitterspar from the Brossa valley in Piedmont and 
 other localities, distinguished by a rather large amount of iron. A specimen from 
 TraverseUa, analysed by Hirzel (Zeitsch. f. Pharm. 1850, p. 24), yielded 11-13 per 
 cent, ferrous carbonate. 
 
 BROUSOBTETTIA TXlffCTORZA or Morus tinctoria. The plant which 
 yields yellow-wood. (See MORUS and MORINTANNIC ACID.) 
 
 B&OWRT BERRIES. The fruit of Eubus fructicosus. See EUBUS. 
 
 BRVCIIfE. Canimarinc. Vomicine.C 23 W*WW + 4H 2 (Pelletier and Ca- 
 ventou (1819), Ann. Ch. Phys. [2] xii. 118; xxvi. 53. Pelletier and Dumas, 
 ibid. xxiv. 176. Corriol, J. Pharm. xi. 495. Liebig, Ann. Ch. Phys. [2] xlvii. 
 172; Ann. Ch. Pharm. xxxi. 50. Kegnault, Ann. Ch.Phys. [2] Ixviii. 113). This 
 vegetable alkaloid exists, together with strychnine, in nux vomica (the seed of Strych- 
 nos nux vomica), in the bean of St. Ignatius (the seed of Strychnos Ignatii), in the 
 wood of Strychnos Colubrina, and in upas tieute, an extract prepared from the bark of 
 the Strychnos tieute, and used by some of the natives of the East Indian Archipelago, 
 for poisoning their arrows. It also exists in large quantity, and unaccompanied by 
 strychnine, in false angustura bark, originally supposed to be the bark of Brucia an- 
 tidysenterica, but now ascertained to belong to a species of strychnos, probably Strych- 
 nos nux vomica. 
 
 Preparation. 1. From false angustura lark. The pulverised bark is treated with 
 ether to remove fatty matter, then digested in strong alcohol; the dry alcoholic ex- 
 tract is dissolved in water; the colouring matter precipitated by subacetate of lead ; the 
 excess of lead removed by sulphuretted hydrogen ; and the liquid, which contains the 
 brucine in solution, is boiled with magnesia, again filtered and evaporated. The 
 brucine is thus obtained in the form of a granular mass, generally coloured. To 
 purify this product, it is saturated with oxalic acid ; the oxalate of brucine is washed 
 with absolute alcohol cooled to C. which dissolves the colouring matter, then 
 reclissolved in water, and decomposed by lime or magnesia ; and the brucine thus set 
 free, is redissolved in alcohol and crystallised by slow evaporation (Pelletier and 
 Caventou). Thenard (Traite de Chimie, 6th ed. iv. 281), recommends as an 
 economical mode of preparing brucine, to treat the bark with boiling water, add oxalic 
 acid to the aqueous decoction, concentrate by evaporation, and purify the oxalate of 
 brucine with cold alcohol, as above. 
 
 2. From the seeds of Strychnos nux vomica, $c. The mother-liquors obtained in 
 the preparation of strychnine from these seeds (see STKYCHXINE), contain brucine, 
 which may be obtained from them by concentrating to the consistence of syrup, and 
 slightly supersaturating with dilute sulphuric acid. The mixture, if left to itself for 
 a few days, deposits crystals of sulphate of brucine, which are to be pressed, redis- 
 solved in boiling water, and decolorised by animal charcoal. The brucine is then 
 separated by ammonia. 
 
 Properties. Brucine crystallises by slow evaporation from its solution in hydrated 
 alcohol, in oblique rhomboidal prisms, often rather large, and sometimes agglomerated 
 in heads like mushrooms. By rapid crystallisation from boiling water, nacreous 
 laminated masses are obtained, having the aspect of boric acid. The crystals contain 
 4 at. water of crystallisation (= 15 '45 per cent.) ; they effloresce quickly in dry air, 
 
682 BRUCINE. 
 
 and melt in their water of crystallisation at a little above 100 C. They dissolve in 
 850 pts. of cold, and 500 pts. of boiling water; they are very soluble in alcohol, spar- 
 ingly in essential oils, insoluble in ether and in fat oils. The alcoholic solution turns 
 the plane of polarisation to the left; specific rotatory power = 61 27'. Acids 
 diminish the rotatory power. 
 
 Brucine is poisonous, and acts on the animal economy like strychnine, but with 
 much less energy. 
 
 Decompositions. 1. Strong nitric acid colours brucine deep red, forming a peculiar 
 nitro-compound (cacotheline), and evolving nitrite of methyl, together with nitric 
 oxide and carbonic anhydride, this last not being a direct product of the reaction, but 
 resulting from the decomposition of oxalic acid previously formed. (Strecker, Ann. 
 Ch. Pharm. xci. 76.) 
 
 C23H 26 N20 4 + 5HN0 3 = C 20 H 22 N 4 9 + CH 3 .N0 2 + C 2 H 2 + 2NO + 2H 2 
 
 Cacotheline. Nitrite of Oxalic 
 
 methyl. acid. 
 
 The addition of protochloride of tin to the mixture changes the red colour to a fine 
 violet. This, together with the red colour first produced, is quite characteristic of 
 brucine, and serves to distinguish it from other alkaloids. 2. Strong sulphuric acid 
 imparts to brucine, first a rose, then a yellow, and then a yellowish-green colour. 
 3. Brucine boiled with peroxide of lead and excess of sulphuric acid, forms a brown or 
 red mass. This character further distinguishes brucine from strychnine, which, when 
 treated with sulphuric acid and peroxide of lead, assumes a blue colour, changing 
 through violet and red to yellow. 4. Brucine distilled with sulphuric acid and ptr- 
 oxide of manganese, gives off inflammable vapours and a liquid (probably hydrate of 
 methyl), which burns with a blue flame ; the same liquid is produced on treating 
 brucine with mercuric oxide, or with sulphuric acid and chromate of potassium, car- 
 bonic and formic acids being likewise evolved in the latter case. 5. Chlorine does 
 not produce immediate turbidity in a solution of brucine, but colours it yellow, and 
 afterwards red ; this last colour disappears after a while, the liquid at the same time 
 depositing yellow uncrystallisable flakes. 6. Bromine dissolved in alcohol, quickly 
 attacks brucine, colouring it violet. With a weak solution of bromine and sulphate of 
 brucine, a resinous matter is formed, together with bromobrucine. 7. Iodine forms 
 with brucine two peculiar compounds. Iodide of ethyl converts it into hydriodatc 
 of ethylbrucine. 
 
 Combinations. The SALTS OF BRUCINE have a bitter taste, and are for the most part 
 crystallisable. Strong nitric acid colours them red. They are decomposed, not only 
 by mineral alkalis, but also by morphine and strychnine, which precipitate the 
 brucine. When diluted with water and mixed with a slight excess of tartaric acid, 
 they are not precipitated by acid carbonates of alkali-metals. 
 
 ACETATE OF BRUCINE is very soluble and uncrystallisable. 
 
 CmoBATE OF BBUCINE. Transparent rhombs. Decomposes suddenly when strongly 
 heated. 
 
 HYDBOCHLOBATE OF BBTJCINE, C 23 H 26 N 2 4 .HC1, or Chloride ofBrucium, C 23 H 27 N 2 4 .C1 
 (at 140 C.) A solution of brucine in dilute hydrochloric acid, yields the salt on cooling 
 in crystalline tufts, moderately soluble in water. The chloromercurate, C 23 H 26 N 2 4 .HC1. 
 2HgCl, is obtained as a crystalline magma on mixing the alcoholic solutions of the two 
 component salts ; and if the mass be heated with a small quantity of alcohol and strong 
 hydrochloric acid, the liquid on cooling, deposits the double salt in long needles, which 
 must be washed, first with a large quantity of water, and then with strong alcohol. 
 
 The chloroplatinatc, C 23 H 26 N 2 4 .HCl.PtCF, is obtained as a precipitate of a fine 
 yellow colour, by mixing a solution of sulphate of brucine with dichloride of platinum. 
 
 HYDBOFERROCYANATES OF BRUCINE. Three of these salts are known: a. 4C 23 IF 6 N 2 4 . 
 4HCy.2FeCy + 2H 2 0. Precipitated on mixing a solution of ferrocyanide of potassium 
 with nitrate of brucine, in shining needles, sparingly soluble in cold, more soluble in hot 
 water and alcohol; very hygroscopic. When heated to 100 C. or boiled with water, 
 it decomposes, giving off hydrocyanic acid, and depositing a blue precipitate. /3. The 
 alcoholic solutions of brucine and hydroferrocyanic acid form a white amorphous pre- 
 cipitate soluble in excess of brucine. It is nearly insoluble in water and in alcohol, 
 has an acid reaction, and is rapidly decomposed by heat. 7. A cold solution of brucine 
 forms with ferricyanide (red prussiate) of potassium, a deep yellow crystalline preci- 
 pitate, which appears to be more stable than the salt, &c. (Br andes, Ann. Ch. 
 Pharm. Ixvi. 266.) 
 
 HYDBOFLUATE OF BRUCINE. A solution of brucine in warm, moderately concen- 
 trated hydrofluoric acid, deposits, on cooling, small colourless prisms, moderately soluble 
 in water, sparingly in boiling alcohol, nearly insoluble in cold alcohol. Gives off 3'34 
 per cent, water at 100 C. 
 
BRUCINE. 683 
 
 HYDBIODATE OF BBUCINE. C 23 H 26 N 2 4 .HI + aq. Eectangular laminae, or very short 
 prisms ; sparingly soluble in cold, more soluble in hot water ; dissolves in alcohol more 
 readily than in water. (Eegnault.) 
 
 IODATE or BBUCINE. A solution of brucine in iodic acid, not in excess, yields by 
 evaporation two salts, viz. an acid salt, which crystallises in hard, transparent, four- 
 sided prisms, and an opaque silky salt, which appears to contain an excess of base. 
 
 IODIDES OF BBUCINE. o. (C 23 H 26 N 2 4 ) 2 ,I 3 . Orange-yellow precipitate, obtained by 
 adding to a cold alcoholic solution of brucine, a quantity of tincture of iodine not suffi- 
 cient to form the compound )8. (Analysis 33*3 per cent, iodine; calc. 32'4 per cent.) 
 
 /3. C 23 H 26 N 2 4 .I 3 . Produced by triturating brucine with excess of iodine, either in 
 powder or in alcoholic tincture. Brown powder soluble in hot alcohol. Treated with 
 a hot dilute acid, it gives off iodine and yields a salt of brucine. With nitrate of 
 silver, it gives a precipitate of iodide of silver. Gave by analysis 36'13 per cent. C ; 
 3-69 H, and 45*66 I; calc. 35'8 C, 3*4 H, and 48'9 I. (Pe lie tier, Ann. Ch. Phys. 
 [2] xliii. 176.) 
 
 NITBATE OF BBUCINE. C 23 H 26 N 2 4 .HN0 3 + 2aq. A solution of brucine in dilute 
 nitric acid yields this salt in colourless four-sided prisms, bevelled at the summits. 
 Less soluble in water than nitrate of strychnine. 
 
 OXALATE OF BBUCINE crystallises in long needles, especially when the acid is in 
 excess. Sparingly soluble in absolute alcohol. 
 
 PEBCHLOBATE OF BBUCINE. Small prisms, sparingly soluble in cold water, more 
 soluble in hot water and in alcohol. Gives off 5'4 per cent, water at 170 C., and 
 explodes at a higher temperature. 
 
 PEBIODATE OF BBUCINE crystallises from an alcoholic solution by evaporation at 
 30 or 40 C. in beautiful colourless needles, which are decomposed by heat with a 
 slight noise. Moderately soluble in water and alcohol ; the solutions turn brown when 
 exposed to the air. (Bodeker, Ann. Ch. Pharm. Ixxi. 64. Langlois, Ann. Ch. 
 Phys. [3] xxxiv. 278.) 
 
 PHOSPHATES OF BBUCINE. a. (C 23 H 26 N 2 4 ) 2 .H 3 P0 4 , or (C 23 H 27 N 2 4 ) 2 .H.P0 4 . (at 
 100 C.) A solution of brucine in tribasic phosphoric acid yields the salt, when concen- 
 trated, in large shortened prisms, having a faint yellowish colour, sparingly soluble in 
 cold water, but dissolving in any proportion in hot water. Neutral to litmus paper. The 
 crystals contain water, which they lose on exposure to the air. At 100 they fuse in 
 their water of crystallisation to a resinous mass, from which it is difficult to expel the 
 last traces of water. )8. Acid Salt. Obtained by using an excess of acid. Crystallises 
 in large rectangular plates, very soluble and efflorescent. 7. Phosphate of Brucine and 
 Soda C- 3 H 26 N 2 4 .NaH 2 P0 4 (at 100 C.) Obtained by digesting brucine with ordinary 
 phosphate of sodium. Short opaque prisms. (Anderson, Phil. Mag. [3] xxxiii. 163.) 
 
 PICBOTOXATE OF BBUCINE crystallises from a boiling solution in white, silky, flexible 
 needles. 
 
 SULPHATE OF BBUCINE. The normal salt, (C 23 H 26 N 2 4 ) S .H 2 S0 4 + 7aq. is obtained 
 by saturating brucine with dilute sulphydric acid. Long needles, very soluble in 
 water, sparingly in alcohol; gives off its water at 130C. An acid sulphate is ob- 
 tained by crystallising the normal salt with sulphuric acid, and removing the excess 
 of acid by washing with ether. Double sulphates. On adding brucine to a solution of 
 sulphate of copper or iron, part only of the metallic base is precipitated. 
 
 SULPHOCYANATE OF BBUCINE. C 23 H 26 N 2 4 .HCyS. Obtained by saturating an alco- 
 holic solution of brucine with a moderately concentrated solution of sulphocyanic acid. 
 Colourless scales, anhydrous, soluble in water, infusible at 100 C. 
 
 TABTBATES OF BBUCINE. a. Normal tartratcs. (C 2S H 26 N 2 4 ) 2 .C 4 H 6 6 + 5| aq. 
 8aq. and 14aq. Obtained in limpid well-defined crystals by dissolving 2 at. brucine 
 in a hot aqueous solution of 1 at. tartaric acid. Very soluble in hot, sparingly in cold 
 water. a. The tartrate (dextro-rotatory) is deposited immediately in limpid laminae, 
 containing 8 at. water, 7| at. of which are given off at 100 C., and the remainder at 
 150 (in all 13'22 per cent.; by calculation 13-18 percent.) Crystallised from 95 per 
 cent, alcohol, the same salt contains only 5| at. water, or 11 at. water to 2 at. of the 
 salt, 5 of which are given off at 100 C., and the remainder at 150 (in all 10 per cent. ; 
 by calculation 9 '5 per cent.) The antitartrate (lavo-rotatory) always contains 14H 2 O, 
 whether crystallised from water or from strong alcohol. It effloresces quickly in sum- 
 mer; gives off 20-66 per cent, water at 100, and 1 per cent, more at 150 (in all 21 
 per cent. = 14 at.) 
 
 & Acid tartrates. C 23 H 26 N 2 7 .C 4 H G 6 -f 5 aq. Obtained by mixing brucine and 
 tartaric acid in equal numbers of atoms. The tartrate precipitates immediately 
 and completely, as a granular crystalline powder. It is always anhydrous, whether 
 crystallised from water or from alcohol. Begins to decompose at about 200 C. The 
 
684 BRUCINE BRYONIN. 
 
 antitartrate contains 5 at. water (calc. 157 per cent. ; exp. 14*5 per cent.) : gives off 
 13-3 per cent. (4at.)at 100, the rest at 150. Very soluble in hot, sparingly in cold 
 water. Effloresces easily in dry air. (Pasteur, Ann. Ch. Phys. [3] xxxviii. 472.) 
 
 THIOSULPHATE, or HYPOSULPHITE OF BRUCINE (C 23 H 26 N 2 4 ) 2 .H'-S'- > 3 + 5aq. (air- 
 dried), is formed when a solution of brucine, mixed with alcohol and sulphide of am- 
 monium, is exposed for some time to the air. It crystallises in prismatic needles, 
 which dissolve in 105 pts. of cold water, and give off 1 at. water when dried over oil 
 of vitriol. (How, Ed. N. Phil. J. [new ser.] vol. xcviii). 
 
 Substitution-derivatives of Brucine. 
 
 BROMOBRUCINE, C 2S H 85 BrN-0'. When a, solution of bromine in dilute alcohol is 
 added to an aqueous solution of sulphate of brucine, a resinous substance immediately 
 forms : and if the addition of the bromine be continued till two-thirds of the brucine 
 is converted into this substance, the decanted solution then precipitated by ammonia, 
 the precipitate dissolved in very weak alcohol, and boiling water containing a little 
 alcohol poured by small portions into the liquid, and afterwards a little pure water, 
 also boiling, a slight turbidity soon appears ; and on leaving the solution to cool, 
 bromobrucine is deposited in small needles, having a slight brown colour. It gave by 
 analysis 17'5 per cent, bromine (calc. 16'9 per cent.) It is not coloured red by strong 
 nitric acid. (Laurent, Ann. Ch. Phys. [3] xxiv. 314.) 
 
 ETHYLBRUCINE. C 23 H 25 (C 2 H 5 )N 2 4 The hydriodate of this base is obtained by 
 
 treating a cooled alcoholic solution of brucine with excess of iodide of ethyl, in crystals 
 containing 2[C 23 H 25 (C 2 H 5 )N 2 4 .HI] + aq. insoluble in water, but readily soluble in 
 hot alcohol. Potash does not separate the base from this salt ; but on treating the 
 solution with recently precipitated oxide of silver, ethylbrucine [? hydrate of ethyl- 
 brucium, C 23 H 26 (C 2 H 5 )N'-'0 4 .H.O, analogous to hydrate of ammonium] is obtained. 
 This base dissolves readily in water, alcohol, and ether, but cannot be obtained in the 
 solid state. The solution has a strong alkaline reaction, precipitates ferric oxide, zinc- 
 oxide, and alumina, redissolving the two latter in excess. It decomposes ammonia- 
 salts, and absorbs carbonic acid from the air. With nitric acid, it gives the same red 
 colour as brucine. It neutralises acids completely. The nitrate and hydrochlorate 
 crystallise, their solutions however becoming coloured during evaporation. The hydro- 
 chlorate forms with dichloride of platinum a crystalline double salt, containing 
 C 23 H 25 (C 2 H 5 )N 2 4 .HCl.PtCl 2 . (Gunning, J. pr. Chem. Ixvii. 46.) 
 
 HRUCITE. Nemalite. Lancasterite. Native Magnesia. MgHO, the magnesium 
 being sometimes partly replaced by iron. Crystallises in rhombohedral forms. Primary 
 form R = 82 15', generally forming the combinations oR . co R. Cleavage very easy 
 parallel to the base. It is usually foliated or massive ; also fibrous, the fibres being 
 separable and elastic. Hardness =1 -5. Specific gravity 2-35 (Hardinger). White 
 inclining to grey, blue or green, with pearly lustre. Streak white. Transparent in 
 various degrees, sometimes translucent on the edges only. Sectile. Flexible in thin 
 laminae. Gives off water when heated, but does not fuse. Dissolves in acids without 
 efflorescence. It accompanies other magnesian minerals in serpentine, in Unst, one 
 of the Shetland isles, where it is sometimes found in regular crystals ; at Pyschminsk 
 in the Ural ; at Groujat in France ; at Hoboken New Jersey ; and in the State of New 
 York. (Dana, ii. 133.) 
 
 The name Brucite is also used as a synonyme of CHONDRODITE (q. v.} 
 
 B RUN OIi 1C ACID. A substance obtained by Runge from coal-tar naphtha 
 (Pogg. Ann. xxi. 65, 315 ; xxxii. 308). When the alkaline liquid obtained by treat- 
 ing coal-tar naphtha with milk of lime, is mixed with an acid, a mixture of phenic or 
 carbolic acid, rosolic acid and brunolic acid separates out; and on distilling this 
 mixture with water, the phenic acid passes over, leaving a brown pitchy residue, 
 containing rosolic and brunolic acid. When this mixture is dissolved in a small quan- 
 tity of alcohol, and milk of lime added, a rose-coloured solution is formed, containing 
 rosolate of calcium, while brunolate of calcium separates as a brown precipitate, which 
 when decomposed by hydrochloric acid, yields brunolic acid in brown flakes. It ap- 
 pears to combine with bases, but neither the acid itself nor any of its salts have yet 
 been obtained in a definite state. 
 
 BRUNS w iCK-GREET<r. A green pigment consisting of oxychloride of copper, 
 Cu 8 Cl 2 3 = 2CuC1.3Cu 2 0, prepared by moistening copper turnings with hydrochloric 
 acid or solution of sal-ammoniac, and leaving them in contact with the air. The oxy- 
 chloride then forms on the surface, and is washed off with water, and dried at a gentle 
 heat. (See COPPER.) 
 
 BRYOIDI3NT. One of the constituents of the resin of arbol-a-brea (p. 354). 
 
 BRYONTW. The bitter principle of the root of the red-berried bryony (Bryonia 
 dio'ica'). It may be obtained by treating the root with boiling water, precipitating the 
 filtered liquid with subacetate of lead, decomposing the precipitate with sulphuretted 
 
BUBULIN BUCKWHEAT. 
 
 685 
 
 hydrogen, evaporating the filtered liquid, and exhausting the residue with alcohol 
 (Brandes and Firnhaber, Brandes' Arch. Pharm. iii. 356). It is a yellowish- white 
 mass, sometimes red or brownish ; tastes sweetish at first, then styptic and very bitter. 
 Soluble in water and alcohol, insoluble in ether. Sulphuric acid dissolves it, forming 
 a blue liquid, which changes to green. It is not altered by alkalis. The aqueous 
 solution forms white precipitates with nitrate of silver, mercurous nitrate, and subacetate 
 of lead. Bryonin acts as a drastic purgative, and in large doses is poisonous. (G-er h. 
 Traite, iv. 274.) 
 
 According to Walz (Chem. Centralb. 1859, p. 5), the alcoholic extract of bryony 
 root contains two bitter substances, bryonin and bryonitin, which maybe sepa- 
 rated by treating the aqueous infusion of the alcoholic extract with subacetate of lead, 
 which precipitates the greater part of the bryonitin, leaving bryonin in solution. 
 Bryonin, when freed from adhering resin by treatment with absolute ether, is a white 
 or slightly coloured granular substance, transparent in thin layers, and according to 
 Walz, contains C^H^O 19 ; but the simpler formula, C 5 H 8 2 , agrees well enough with 
 the results of the analysis. It appears to be a glucoside, and is resolved by boiling 
 with dilute sulphuric acid, into glucose, and two amorphous bodies, viz. bryoretin, 
 soluble in ether, and hydrobryoretin, insoluble in ether, but soluble in alcohol: 
 C 48 H 84 21 = C 21 H 35 T + C 21 H 37 8 + C 6 H 12 O a 
 
 Bryonin. Bryoretin. Hydro- Glucose, 
 
 bryoretin. 
 
 Bryonitin forms a white crystalline mass, soluble in water and ether, insoluble in 
 alcohol. Walz regards the bryonin of Brandes and Firnhaber as an impure substance. 
 BRYORETIKT. See the last article. 
 
 BUBUIiIJff (from fiovs, ox). The name of a peculiar substance, said by Morin 
 to exist in cow-dung, and to be copiously precipitated by metallic salts, tincture of 
 galls, and alum, and therefore to be active in the application of cow-dung to calico- 
 printing. 
 
 BUCHOLZITE. A silicate of aluminium, varying in composition between 
 Al 4 3 .Si0 2 and 2Al 4 3 .3Si0 2 , and probably nothing but fibrous disthene mixed with 
 quartz. (See DISTHENE and SKLHMA.NITE.) 
 BirCKXiANDXTE. See EPIDOTE. 
 BUCKTHORN. See EHAMNUS. 
 
 BUCKWHEAT. Polygonum fagopyrum, and P. tartaricum. A plant indigenous 
 in Asia, but much cultivated in the North of Europe, where the flour is used for food. 
 The dry plant yields on the average, 43 per cent, by weight of grain, and 57 straw. 
 The seed of buckwheat contains on the average : 
 
 Air dried. Anhydrous. 
 
 Nitrogenous matter 8'6 10-0 
 
 Starch, &c. 51 '9 60'5 
 
 Woody fibre, &c 231 26'9 
 
 Ash 2-2 2-5 
 
 Water 14'2 
 
 Pierre (Compt. rend. xlvi. 203) found in 100 pts. of buckwheat-seed, 2'1 pts. 
 nitrogen, 0'5 phosphoric anhydride, and 3'2 fat ; in 100 pts. of commercial buckwheat 
 flour: 1'3 pts. nitrogen; in 100 pts. of the coarse yellow flour: 5'6 nitrogen, 2'4 phos- 
 phoric anhydride, and 7'2 fat; in the bran, 2'4 nitrogen, 1'2 phosphoric anhydride, 
 and 4-8 fat. Mulder found in 100 pts. of buckwheat flour 7'5 pts. nitrogenous con- 
 stituents, and the same in the bran. 
 
 Composition of the Ash of the Grain and Straw of Buckwheat. 
 
 
 Grain. 
 
 Straw. 
 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5 
 
 6 
 
 7 
 
 8 
 
 9 
 
 Potash . 
 
 8-7 
 
 15-0 
 
 10-3 
 
 317 
 
 21-6 
 
 39-6 
 
 40-5 
 
 28-2 
 
 23-9 
 
 Soda 
 
 20-1 
 
 24-0 
 
 ,__ 
 
 
 
 
 
 
 
 Lime 
 
 67 
 
 11'5 
 
 22-0 
 
 157 
 
 iTo 
 
 IJTs 
 
 11-6 
 
 14-1 
 
 18-6 
 
 Magnesia 
 
 10-4 
 
 13-5 
 
 40-3 
 
 1 G 
 
 19 
 
 3-2 
 
 1-4 
 
 4-7 
 
 4-2 
 
 Ferric oxide 
 
 1-0 
 
 0-6 
 
 0-5 
 
 
 
 
 
 
 
 
 Sulphuric anhydride 
 
 2-2 
 
 5-4 
 
 08 
 
 4-7 
 
 ~2'S 
 
 77 
 
 Ts 
 
 7'1 
 
 3-5 
 
 Silicic , 
 
 07 
 
 106 
 
 4-4 
 
 3-6 
 
 4-1 
 
 4-1 
 
 4-2 
 
 4-8 
 
 5-2 
 
 Phosphoric , 
 Chloride of potassium 
 Chloride of sodium 
 
 50-1 
 
 12-5 
 1-0 
 
 9-0 
 4~9 
 
 10-3 
 7-4 
 45 
 
 9-5 
 26-9 
 3'0 
 
 64 
 0-8 
 3-2 
 
 8-9 
 3-1 
 3-7 
 
 109 
 68 
 34 
 
 10-0 
 9-7 
 1-7 
 
 Carbonic anhydride 
 
 
 
 
 
 20-4 
 
 16-1 
 
 27-1 
 
 22-2 
 
 20-0 
 
 23-1 
 
 Alumina . . 
 
 M 
 
 P9 
 
 0-8 
 
 __ 
 
 _ 
 
 
 ma| 
 
 
 
 
 Manganic oxide 
 
 
 
 3'2 
 
 1-0 
 
 
 
 
 
 
 
 
 
 
 
 
 
686 BUCKWHEAT BUTEA GUM. 
 
 1. Analysed by Bichon (Ann. Ch. Pharm. 1. 419). 2, 3. By Sprengel (J. techn. 
 Chem. vi. 402 ; x. 350). 49. By Wolff (J. pr. Chem. Hi. 65). 4. Straw of buck- 
 wheat grown in unmanured soil ; 5, on soil manured with chloride of sodium ; 6. with 
 nitrate of potassium ; 7, with potashes ; 8, with sulphate of magnesium ; 9, with lime. 
 
 Sprengel found in the air-dried straw, 3'20 per cent. ash. 
 
 Colouring Matters of Buckwheat. The leaves contain a yellow colouring-matter, 
 first observed by Nachtigal (Jahresber. f. Chem. 1849, p. 713), further examined by 
 Schunck (Chem. Gaz. 1858, Jan. 18 ; Jahresber. 1857, p. 489). According to Schunck, 
 its composition may be most simply expressed by the formula, C 3 H 4 2 , and it is pro- 
 bably identical with rut in (q. v.\ and with Moldenhauer's ilixanthin. It crystallises 
 in yellow needles, dissolves sparingly in cold water, more readily in boiling water, 
 more still in alcohol. Alkalis dissolve it, forming a deep yellow solution, from which 
 it is precipitated by acids ; if, however, the solution be exposed to the air, the colour- 
 ing matter is transformed into an amorphous substance, easily soluble in water, and no 
 longer precipitable by acids. Hydrochloric and sulphuric acids change the yellow 
 colour of the crystalline substance to deep orange : but water restores it. Dilute sul- 
 phuric acid does not decompose it, even at boiling heat ; nitric acid converts it into 
 oxalic acid. With oxide of lead, it forms a bright yellow compound, like chromate of 
 lead, and communicates a bright yellow colour to cotton stuffs mordanted with acetate 
 of alumina. The presence of foreign matters in the crude extract of buckwheat straw, 
 renders the colour somewhat impure. According to Nachtigal, 5 pts. of buckwheat 
 straw contain as much colouring matter as 1 pt. of quercitron. According to Schunck, 
 1 000 pts. of the fresh leaves contain rather more than 1 pt. of pure colouring matter. 
 
 Buckwheat straw has been said to yield indigo by fermentation ; a statement which, 
 however, is not confirmed by the observation of Schunck (Handw. d. Chem. 2 te Aufl. 
 ii. [2] 551. Ure's Dictionary of Arts, Manufactures, and Mines, ii. 467.) 
 
 BUCURU1V1 A:NG A RESIN. A fossil resin, occurring in an auriferous alluvium 
 near Bucurumanga in New Granada. It is light yellow, transparent, somewhat heavier 
 than water; becomes strongly electric by friction; is insoluble in alcohol; swells up in 
 ether and becomes opaque. It melts when heated, and burns in the air without 
 residue. It resembles amber in outward appearance, but does not yield succinic acid 
 by dry distillation. It contains 82*7 per cent, carbon, 10'8 hydrogen, and 6 '5 oxygen. 
 (Boussingault, Ann. Ch. Phys. [3] vi. 507.) 
 
 BUETCTIRT. A substance obtained by Buchner, from the bark of Buena hexandra. 
 
 BUHRSTONE. A cellular flinty quartz rock. 
 
 BUBLKlT LEAVES. The leaves of Diosma crenata, a rutaceous plant growing 
 at the Cape of Good Hope. Gass incourt (Buchn. Kepert. Pharm. xxvi. 328) found in 
 1000 pts. of them, besides gum, resin, &c., 6'6 pts. of a volatile oil, having a gold-yellow 
 colour, a sharp irritating taste and odour, lighter than water, and somewhat soluble 
 therein. Brandes (Arch. d. N. Apoth. Ver. xxii. 229) found malic and oxalic acids 
 in the leaves, besides albumin, gum, resins, &c. ; and in 1000 pts. 88 pts. volatile oil, 
 and 40 pts. of a yellowish-brown bitter substance, soluble in water, which he called dios- 
 min. Landerer (Buchner's Rupert. Ixxxiv. 63) found in the alcoholic tincture of 
 bukku leaves, a crystalline bitter deposit, which, however, was insoluble in water. 
 
 BURATITE. A hydrated carbonate of zinc, copper, and calcium, occurring in 
 verdigris-green, radiated, acicular crystals, or plumose aggregations, of specific gravity 
 3 -3 2, at Chessy and Frammont in France, and at Volterra and Temperino in Tuscany 
 (Delesse, Ann. Ch. Phys. [3] xviii. 478). It is very variable in composition, and is 
 probably a mixture of several minerals. 
 
 BURETTE. See ANALYSIS, VOLUMETRIC (p. 256). 
 
 BURGUNDY PITCH or RESIN*. Poix de Bourgogne, Fix alba, Poix blanche, 
 is the white pitch obtained from pine-wood. The resin of Pinus picea purified by 
 repeated boiling with water, is also called Burgundy pitch. (See PINE-RESINS and 
 PITCH.) 
 
 BURSERA GUIMEMIFERA. Gommart. A terebinthaceous tree growing in 
 the Antilles. It yields a dry white resin having a crystalline fracture, and an odour 
 of turpentine, also like that of elemi. It is but slightly fusible, but diffuses itself 
 through boiling water in small tenacious granules. The resin distilled with water 
 yields 47 per cent, of a coloured volatile oil (Gommart-oil, Essence de gommarf), 
 which, when purified by standing in contact with potash, then with potassium, and 
 rectification, has the same odour, composition, and vapour-density as oil of turpentine, 
 and forms with hydrochloric acid, two compounds, one of which is crystalline and con- 
 sists of C 10 H I6 .2HC1. (H. Deville, Ann. Ch. Phys. [3] xxvii. 90.) 
 
 BUST AIVXITE. Native silicate of manganese. See KHODONITE. 
 
 BUTEA GUM. Bengal Kino. The juice of Butea frondosa, Koxb., often sent into 
 
BUTIC ACID BUTTER. 687 
 
 the market instead of genuiiie kino. It forms black-brown, slightly lustrous, brittle 
 lumps, has an astringent taste, and yields pyrocatechin by dry distillation. 
 
 BUTIC ACID. A solid fatty acid, which Heintz obtained (Pogg. Ann. xc. 
 137), though not pure, by partially precipitating an alcoholic solution of the solid fatty 
 acids of butter with acetate of magnesium, this acid then forming the less soluble com- 
 pound. Heintz is of opinion that in the pure state it would have the composition of 
 arachidic acid C 20 H 40 0-. (See p. 353.) 
 
 BUTTER. The fatty non-azotised constituent of milk. It is suspended in the milk 
 in minute globules, and rises to the surface, when the milk is left at rest, in the form of 
 cream, together with a certain quantity of casein and the other constituents of the milk. 
 Butter is obtained from cream by agitation or churning, which causes the fat-globules 
 to unite in larger masses and separate completely from the watery liquid, called 
 butter-milk. Butter thus obtained and in the state in which it is commonly used, consists 
 of | pure fat or real butter and | of butter-milk, from which it may be separated by 
 melting it in a tall vessel at about 60 C., decanting the clear fat which floats' at the 
 top, and washing with water at 40 C. Ordinary butter from cow's milk, is com- 
 posed, according to Chevreul, of stearin, margarin, and olein, with small quantities of 
 butyrin, caproin, and caprin, to which its odour is due. According to Heintz, it con- 
 tains olein, a large quantity of palmitin, and a small quantity of stearin, together 
 with very small quantities of glycerides, yielding by saponification, myristic acid and 
 butic acid, C 20 H 10 2 (vid. sup.) 
 
 Butter dissolves in 28 pts. of boiling alcohol of specific gravity 0-82. It is very 
 apt to turn rancid, a change which consists in the separation of the fatty acids from 
 the glycerin, and may be prevented to a certain extent by salting or by melting it, so 
 as to separate the foreign matters which induce the decomposition. 
 
 " At Constantinople, the butter brought from the Crimea and the Kirban, is kept 
 sweet by melting it while fresh over a very slow fire, and removing the scum as it 
 rises. By melting butter in this manner, and then salting it, it may be kept good 
 and fine-tasted for two years ; moreover, this melting, if carefully done, injures neither 
 the taste nor colour. Thenard too recommends the same method. He directs the 
 the melting to be done on a water-bath, or at a heat not exceeding 140 Fahr. ; and 
 to be continued till all the caseous matter has subsided to the bottom, and the butter 
 is transparent. It is then to be decanted, or strained through a cloth, and cooled in 
 a mixture of pounded ice and salt, or at least in cold spring water, othewise it will 
 become lumpy by crystallising, and likewise not resist the action of the air so well. 
 Kept in a close vessel, and in a cool place, it will thus remain six months or more, 
 nearly as good as at first, particularly after the top is taken off. If beaten up with 
 one-sixth of its weight of the cheesymatter when used, it will in some degree resemble 
 fresh butter in appearance. The taste of rancid butter, he adds, may be much cor- 
 rected by melting and cooling in this manner. 
 
 "Another mode of curing butter, is as follows: Take one part of sugar, one of nitre, 
 and two of the best Spanish great salt, and rub them together into a fine powder. 
 This composition is to be mixed thoroughly with the butter, as soon as it is com- 
 pletely freed from the milk, in the proportion of one ounce to sixteen ; and the butter 
 thus prepared is to be pressed tight into the vessel prepared for it, so as to leave no 
 vacuities. This butter does not taste well, till it has stood at least a fortnight : it then 
 lias a rich marrow flavour, that no butter ever acquires ; and with proper care may be 
 kept for years in this climate, or carried to the East Indies, if packed so as not to melt. 
 
 " At Kebba, in the interior of Africa, Mungo Park informs us, there is a tree much 
 resembling the American oak, producing a nut in appearance somewhat like an olive. 
 The kernel of this nut, by boiling in water, affords a kind of butter, which is whiter, 
 firmer, and of a richer flavour than any he ever tasted made from cows' milk, and will 
 keep without salt the whole year. The natives call it shea toulou, or tree butter. 
 Large quantities of it are made every season." "U". 
 
 Butter is often largely adulterated with water and salt, which are introduced while 
 the butter is in the melted state and incorporated by stirring till the whole is cold. 
 The proportion of water may be determined very nearly by melting a portion of the 
 butter in a narrow glass vessel, such as a common ounce phial, and leaving it to stand 
 in a warm place till the water settles to the bottom. The quantity of the water should 
 not exceed 1 per cent. The amount of salt is determined by calcination, any quantity 
 beyond 5 per cent, may be regarded as adulteration. Butter is also frequently adul- 
 terated with lard, in places where that kind of fat is cheap. (For the preparation of 
 butter, see Ure's Dictionary of Arts, Manufactures, and Mines, also Muspratt's Che- 
 mistry, i. 397.) 
 
 BUTTER OP ANTIMONY, TIW, &c. Old names for anhydrous metallic 
 chlorides having a buttery consistence. 
 
688 BUTYLACTTC, BUTYRACETIC ACID. 
 
 BITTY J* and derivatives. Syn. TETRYL and derivatives. 
 
 BTTTYX.ACTIC ACID. Oxybutyric add. C'H 8 3 = (C 4 H 6 0)".H 2 .0 2 . (A. 
 
 Wurtz, Ann. Cli. Pliarm. cvii. 197.) This acid has hitherto been obtained only by the 
 oxidation of amyl-glycol (p. 208) ; but it might doubtless be produced also by the 
 oxidation of butyl-glycol, as well as by other processes. It is prepared by gently 
 heating 14 pts. of amyl-glycol with 30 pts. nitric acid (HNO 3 ) and 42 pts. water, and 
 evaporating over quick lime ; it then remains in the form of a syrupy liquid. 
 
 Butylactic acid bears to butyric acid the same relation that lactic acid bears to pro- 
 pionic acid, and in consequence of this relation, it is regarded as dibasic (see LACTIC 
 ACID), although all the salts yet obtained from it contain but one atom of metal in 
 place of hydrogen. The barium-salt, C 4 H 7 Ba0 3 , is uncrystallisable, dissolves in all 
 proportions, and with moderate facility, in dilute alcohol, but is insoluble in absolute 
 alcohol ; ether precipitates it from the alcoholic solution. The calcium-salt, C 4 H 7 Ca0 3 
 (dried at 120 C.), separates from the aqueous solution by spontaneous evaporation in 
 warty crystals, which dissolve readily in water and in absolute alcohol, but are in- 
 soluble in ether. The zinc-salt, C 4 H 7 Zn0 3 + aq., crystallises in shining laminse, which 
 dissolve in 160 pts. of water at 15 C., but are insoluble in absolute alcohol. The 
 crystals are permanent in the air, but give off 11 per cent. (2 at.) water at 100 C. 
 
 BUTYRACETIC ACID. Pseudo-acetic Acid. C 3 H 6 2 or C 2 H 4 ? .C 4 H 8 2 . An 
 acid first obtained by Nollner in 1841 (Ann. Ch. Pharm. xxxviii. 229), as a product 
 of the fermentation of a mother-liquor from the preparation of tartaric acid containing 
 a considerable quantity of tartrate of calcium, or by converting crude tartar into im- 
 pure tartrate of calcium, and fermenting the product. Nollner designated this acid 
 pseudo-acetic acid, from its resemblance to acetic acid. Berzelius regarded it as a 
 mixture of acetic and butyric acids. Nickles, however (Compt. rend, xxxiii. 419), 
 showed that, although this acid is easily resolved into acetic and butyric acids, it is, 
 nevertheless a distinct acid, and gave it the name butyracetic acid. Dumas, 
 Malaguti, and Leblanc (Compt. rend. xxv. 781), showed that it is identical in 
 composition and boiling point with propionic acid, which it also resembles in its other 
 physical properties, and moreover stated that its salts are identical with the pro- 
 pionates in composition and crystalline form. Nickles, on the other hand, maintained 
 that the salts differ in certain respects from the corresponding propionates. Lastly, 
 the acid has been examined by Limpricht and v. Uslar (Ann. Ch. Pharm. xciv. 
 321), who have shown that butyracetate of barium yields, by dry distillation, propylal, 
 propione, and propylene (tritylene), in which respect it exactly resembles the propitiate, 
 but that, on the other hand, butyracetic acid separates spontaneously or by distillation, 
 into acetic and butyric acids, which is not the case with propionic acid. On the whole, 
 therefore, butyracetic acid must be regarded as a distinct acid. It appears to be pro- 
 duced only by the fermentation of tartrate of calcium ; acid tartrate of potassium, 
 whether crude or purified, yields by fermentation nothing but acetic acid. According 
 to later experiments of Nickles (J. Pharm. [3] xxxiii. 351), it is likewise obtained 
 by pouring a mixed solution of equivalent qualities of an acetate and a butyrate into 
 dilute sulphuric acid. 
 
 Butyracetic acid resembles propionic acid in most of its properties. It mixes in all 
 proportions with water, and is separated therefrom unaltered by chloride of calcium, a 
 property which distinguishes it from a mere mixture of butyric and acetic acids. 
 According to Dumas, it boils constantly at 140 C. ; but, according to Limpricht and 
 v. Uslar, it begins to boil at 120, at which temperature nearly pure acetic acid passes 
 over, and the boiling point gradually rises to 160, when butyric acid distils over, the 
 boiling point not remaining stationary for any time at 140. It does not yield either a 
 definite anhydride or a definite ether, but in both cases a mixture of acetate and 
 butyrate. 
 
 Butyracetate of 'Barium, C 3 H 5 Ba0 2 + aq., resembles the propionate in composition 
 and properties ; but on decomposing it with sulphate of copper, the acid which is set 
 free separates into butyric and acetic acids (Nickles). The calcium-salt, C 3 H 5 Ca0 2 , 
 forms silky needles, or, according to Nickles, regular octahedrons, which effloresce in 
 the air. The copper-salt crystallises in dark blue-green tables, which give off part of 
 their water of crystallisation at 100 C. It rotates on water, dissolves sparingly in 
 water, more easily in alcohol. 
 
 The neutral lead-salt crystallises from a very concentrated solution at low tempera- 
 tures in cauliflower-like masses. It melts when heated, giving off part of its acid, 
 and deliquesces in moist air. A concentrated solution, to which chloride of barium is 
 added as long as the precipitate first formed disappears on agitation, yields by slow 
 evaporation, a double salt which crystallises in square prisms containing barium and 
 lead, and likewise chlorine. The basic lead-salt is formed by boiling the preceding 
 with oxide of lead. It crystallises from a moderately concentrated solution at a little 
 above C., in octahedrons which contain 42 per cent, water, undergo aqueous fusion 
 
BUTYRAL 689 
 
 below 19, and dissolve readily in alcohol. From a very concentrated solution or from 
 fusion, it crystallises in tables ; at very low temperatures, however, in spherical seg- 
 ments, which, when gently heated, split from the centre outwards with a slight noise. 
 By mixing the boiling solution of the lead-salt with a little ammonia, a crystalline 
 powder is precipitated. (Nollner.) 
 
 The mercurous salt crystallises in satiny scales, which are reddened by light. The 
 potassium-salt crystallises in very deliquescent thin tables. The silver-salt separates 
 on cooling from a boiling solution of the ammonium-salt, mixed with a boiling solution 
 of nitrate of silver, in shining needles resembling acetate of silver and sparingly 
 soluble in water. The sodium-salt crystallises from a somewhat dilute solution in 
 deliquescent octahedrons ; from a more concentrated solution, as a white tallowy amor- 
 phous mass, or as a radio-crystalline mass. The zinc-salt is soluble in water, but de- 
 composes by boiling. 
 
 BUTYRAXi and BTTTYRAXiDEHYDE, C 4 H 8 0. Two compounds are known 
 which have the composition of the term in the butyric series corresponding to that of 
 aldehyde in the acetic series ; they are not, however, identical. 
 
 Butyral was obtained by Chancel (Ann. Ch. Phys. [3] xii. 416), among the pro- 
 ducts of the destructive distillation of butyrate of calcium. The crude product of this 
 operation is a mixture of several substances, of which butyral, boiling at 95 C. is the 
 most volatile, and can be separated from the others by fractional distillation. 
 
 Pure butyral is a colourless, very mobile liquid, with a burning taste, and a sharp 
 and penetrating odour. Its density at 22 C. is 0-821, and it boils at 95. It dissolves 
 a small quantity of water. It is slightly soluble in water, and soluble in all proportions 
 in alcohol, ether, and wood-spirit. It rapidly absorbs oxygen from the atmosphere, 
 and is converted into butyric acid. It is oxidised by solid chromic acid with a slight 
 explosion. It is very inflammable and burns with a brilliant flame. Heated with 
 water and oxide of silver, it reduces part of the oxide to the state of metallic silver, 
 butyrate of silver remaining in solution. On heating it with sulphuric acid, sulphurous 
 acid is liberated, and a small quantity of butyric acid remains in solution. By dilute 
 nitric acid, it is converted into nitropropionic acid. It forms crystalline compounds 
 with acid sulphites of alkali-metals, analogous to those which aldehyde forms. By the 
 action of pentachloride of phosphorus on butyral, hydrochloric acid, oxy chloride of 
 phosphorus, and a peculiar product, C 4 H 7 C1, are formed: 
 
 C 4 H 8 + PCI 5 = C 4 H 7 C1 + HC1 + POC1 3 . 
 
 This product is a colourless, oily, very mobile liquid, lighter than water, with a sharp 
 odour and a biting taste. It is insoluble in water, but soluble in alcohol and in ether. 
 It boils at a little over 100C. ; it is inflammable, and burns with a green-edged 
 flame. It is probable that the action of pentachloride of phosphorus on butyral is 
 analogous to its action on aldehyde, and gives rise to the compound C 4 H 8 C1 2 , 
 homologous with chloride of ethylidene (p. 107), and that at the moment of its 
 formation, this substance is decomposed into hydrochloric acid and the body above 
 described. 
 
 Chlorinated Derivatives of "Butyral. Chlorine acts very energetically on 
 butyral, with the formation of definite compounds containing chlorine in the place of 
 hydrogen. 
 
 Monochlorinated Butyral. C 4 H 7 C10. Produced by passing a current of dry chlorine 
 through butyral by diffused light. The gas is at first absorbed, with evolution of heat 
 and pale red coloration ; afterwards the colour disappears and the liquid gives off torrents 
 of hydrochloric acid gas to the end of the operation. A rapid current of carbonic 
 anhydride is then passed through the liquid heated somewhat below its boiling point, 
 and it is then rectified. It is a transparent limpid liquid, heavier than water; 
 boils at 141 C. ; has a pungent tear-exciting odour. It is insoluble in water, but 
 dissolves in alcohol, and its alcoholic solution does not cloud nitrate of silver. It does 
 not form an amide with ammonia. 
 
 Dicklorinatcd Butyral, C 4 H 6 C1 2 0. When dry chlorine is passed for three hours 
 through butyral exposed to sunlight, the action is observed to slacken after some time. 
 If carbonic anhydride be now passed through the liquid, which is afterwards rectified, a 
 neutral oil is obtained boiling at 200 C. 
 
 Tetrachlorinatcd Butyral, C 4 H 4 C1 4 0. Chlorine is passed for several days through 
 butyral exposed to bright sunshine, the liquid being ultimately heated, and the action 
 continued as long as hydrochloric acid gas continues to be evolved. When purified 
 like the other substances, it forms a thick heavy neutral oil, which boils at a high 
 temperature, with decomposition. 
 
 Butyraldebyde. C'H 8 = C 4 H 7 O.H. This body was obtained by Guckclberger 
 among the products of the action of oxidising agents on fibrin, albumin, and casein. 
 
 VOL. I. Y Y 
 
690 BUTYRAMIDE. 
 
 For the full details of the process, Guckelberger's paper must be referred to (Ann. Ch. ' 
 Pharm. Ixiv. 39). The crude distillate resulting from the action was neutralised with 
 chalk and distilled. A neutral distillate was obtained which consisted of the alde- 
 hydes of the acetic, propionic, butyric, and benzoic series. These were separated by 
 fractional rectification, the portions between 70 and 100 C. which consisted of 
 butyric aldehyde mixed with a little propionic aldehyde, being collected separately. 
 Butyric aldehyde is much less soluble in water than propionic aldehyde, and may be 
 separated from it by agitation with water. To obtain the butyraldehyde quite pure, 
 it is agitated with ammonia, with which it forms a crystalline compound. This is 
 decomposed by the addition of a concentrated solution of alum, the liquid distilled, and 
 the distillate rectified over chloride of calcium. 
 
 When pure, it is a thin, colourless, transparent oil, which has the specific gravity 
 0'80 at 15 C. It boils at 68 to 75, and has an ethereal, somewhat penetrating odour. 
 The small quantity in which this substance has been found, has prevented its com- 
 plete investigation ; but almost all its properties, as far as they have been examined, 
 are identical with those of butyral. It acidifies in the air; an aqueous solution 
 mixed with ammonia, and then with nitrate of silver until the alkaline reaction dis- 
 appears, gives, on the application of heat, a beautiful coating of metallic silver on the 
 sides of the vessel. It differs from its isomer chiefly in its boiling point, its density, 
 and in forming a crystalline compound with ammonia, which butyral does not. 
 
 Butyr -aldehyde-ammonia. NH 3 .C'H 8 + 5aq. Butyraldehyde forms with strong 
 ammonia, a crystalline mass consisting of small acute rhombic octahedrons; from an 
 alcoholic solution, the compound crystallises in large rhombic tables. The dry crystals 
 do not alter in the air, but in the moist state they gradually become brown. Gently 
 heated, they melt, and sublime at a few degrees above 100 C.; more strongly heated, 
 they give off ammonia. Potash does not expel ammonia from them at ordinary tem- 
 peratures. Aqueous acids or alum separate butyraldehyde. Butyraldehyde-ammonia 
 is almost insoluble in water, but soluble in alcohol, and in ether. 
 
 Sulphuretted hydrogen passed into a solution of this body, appears to form a com- 
 pound homologous with thialdine. When the liquid resulting from this action is 
 treated with ether, a sulphuretted oil is obtained, which forms with hydrochloric acid 
 a solid crystalline compound. E. A. 
 
 BUTYRAMIDE. C 4 H 9 NO = C * H ][^JN. This compound, homologous with 
 
 acetamide, is prepared by placing 1 pt. of butyric ether, and 6 pts. of strong aqueous 
 ammonia, in a flask, and frequently agitating the mixture until the action is complete, 
 which generally takes from eight to ten days : the liquid is then evaporated to one- 
 third, and on cooling the butyramide crystallises out: 
 
 C 4 H 7 (C 2 H 5 )0 + NH 3 = C 4 H 9 NO + C 2 H 6 
 
 Butyric ether. Butyramide. Alcohol. 
 
 It crystallises in snow-white, nacreous, transparent tables, which melt at 115 C. to a 
 colourless liquid, and volatilise without residue. It has a sweet, cooling taste, with 
 bitter aftertaste. It is readily soluble in water, also in ether and in alcohol. Its 
 vapour is inflammable. Passed over red-hot lime, or distilled with anhydrous phos- 
 phoric acid, it loses water and yields butyronitrile (cyanide of trityl) : 
 
 C 4 H 9 NO - H*0 = C 4 H 9 N 
 
 Butyra- Butyroni- 
 
 mide. trile. 
 
 Its aqueous solution is decomposed by boiling with fixed alkalis, yielding ammonia and 
 an alkaline butyrate : 
 
 C 4 H 9 NO + KHO = C 4 H 7 K0 2 + NH 3 . 
 
 By pentachloride of phosphorus, it is converted into cyanide of trityl, oxychloride 
 of phosphorus, and hydrochloric acid : 
 
 C 4 H 9 NO + PCI 5 = C'H 7 N + POC1 + 2HC1. 
 
 It is decomposed by nitrous acid, with formation of butyric acid, water, and nitrogen : 
 C 4 H 9 NO + HNO 2 = C 4 H 8 2 + H 2 + N 2 
 
 Butyramide. Nitrous Butyric 
 
 acid. acid. 
 
 Mercuric butyramide. C 4 H 8 HgNO, is obtained by boiling mercuric oxide witli so- 
 lution of butyramide. The filtered solution, when concentrated, deposits the compound 
 in small nacreous crystals, more lustrous than butyramide, which they otherwise re- 
 semble. E. A. 
 
 BUTYRIC ACID. C 4 H 8 2 - C ' H ^ ! 0. Butyric acid is a member of the 
 
BUTYRIC ACID. 691 
 
 series of volatile fatty acids, of the general formula C D H>' n 2 . It was discovered by 
 Chevreul, who obtained it by saponifying butter with alkalis. It occurs in nature both 
 in the free state, and in combination with bases. It is found in perspiration, in the 
 juice expressed from human flesh, and from that of animals ; in crude oil of amber ; 
 and in cod-liver oil. It is found in all liquids containing lactic acid, as a product 
 of the transformation of this substance. Butyric acid is also contained, together with 
 several fatty acids of the same series, in combination with glycerin, in butter from 
 cows and goat's milk. This compound of butyric acid with glycerin is inodorous, 
 and it is to its decomposition on standing, by which butyric acid is set free, that 
 the odour of rancid butter is chiefly due. Butyric acid is a frequent product of the 
 oxidation of organic substances, as when fibrin is treated with sulphuric acid and 
 peroxide of manganese, or when oleic acid is oxidised by nitric acid. It has also been 
 found among the products of the destructive distillation of tobacco (Zeise) and of peat 
 (Sullivan, Jahresber. d. Chem. 1858, 280). Lastly, it has been found in several 
 plants, in certain beetles, 'and in certain mineral waters. (G-m. x. 76 ; xiii. 388 ; 
 Handw. d. Chem. ii. [2] 561.) 
 
 The most important mode of its formation, and that on which the present methods 
 used for its preparation are based, depends on the metamorphosis which starch, sugar, 
 &c. undergo in the presence of substances which act as ferments. Pelouze and G61is 
 have found that butyric acid can be obtained from all amylaceous and saccharine 
 matters, which can be transformed into lactic acid, such as cane-sugar, milk-sugar, 
 starch, dextrin, &c. These substances exposed in water to a temperature of 25 to 30 C. 
 in contact with old cheese, or some other decaying nitrogenous substance, first undergo 
 the lactic fermentation, and are ultimately converted into butyric acid. This latter 
 phase is attended with disengagement of carbonic anhydride and hydrogen : 
 
 C 4 H 8 2 + 2C0 2 + H 4 . 
 
 Lactic acid. Butyric 
 acid. 
 
 The original process given by Pelouze and G-elis, has subsequently been modified by 
 Bensch, whose method is essentially as follows : 6 Ibs. of cane-sugar and an oz 
 of tartaric acid are dissolved in 26 Ibs. of boiling water, and left to stand for some 
 days to allow the cane-sugar to pass into grape-sugar. To this solution, about 4 oz. 
 of decayed cheese, diffused in 8 Ibs. of sour skim-milk, together with 3 Ibs. of chalk, 
 are added, and the whole is left in a place the temperature of which is uniform at about 
 30 35 C. The mixture is frequently stirred, and generally solidifies after ten or 
 twelve days, to a thick mass of lactate of calcium. If this be allowed to stand under 
 the same conditions, the evaporated water being renewed, it again becomes liquid, gas 
 bubbles rise, and at the expiration of five to six weeks, whvn the disengagement of 
 gas has ceased, the whole of the lactic acid (and therefore the whole of the sugar), has 
 passed into butyric acid, which is present as butyrate of calcium. The operation seems 
 to succeed best with large quantities of substance. 
 
 The above solution of butyrate of calcium is mixed with an equal bulk of water, and 
 a solution of eight pounds of crystallised soda is added, with agitation. The solution 
 filtered off from the carbonate of calcium is evaporated to ten pounds, and decomposed 
 by the careful addition of five and a half pounds of sulphuric acid, previously diluted 
 with an equal weight of water. The greater part of the butyric acid then separates as 
 an oily layer on the surface of the solution of the acid sulphate of sodium, and is re- 
 moved by means of a tap-funnel. In order to obtain the butyric acid still contained in 
 the solution of sulphate of sodium, it is distilled, the distillate neutralised with carbonate 
 of sodium, evaporated, and the acid separated as before by means of sulphuric acid. 
 
 The united portions of crude butyric acid, which, besides water, always contain 
 some sulphate of sodium, are mixed with sulphuric acid (about one ounce to one 
 pound) in order to prevent the separation of neutral sulphate of sodium, which would 
 cause convulsive distillation. The distillate consisting of aqueous butyric acid is 
 mixed with fused chloride of calcium, and rectified. At first, dilute acid passes over 
 accompanied by traces of hydrochloric acid ; this afterwards gives place to concentrated 
 acid, which when fractionally distilled, is obtained of a constant boiling point and quite 
 pure. It is better to use sulphuric than hydrochloric acid in the decomposition of 
 butyrate of calcium, as the latter causes the mixture to froth up, and it is difficult to 
 free the butyric acid completely from hydrochloric acid. 
 
 Butyric acid may also be prepared by saponifying butter with an alkali, and distilling 
 the soap with sulphuric acid. But this method is never used for the preparation of 
 pure butyric acid, as its separation from the accompanying soluble fatty acids is very 
 difficult and troublesome. 
 
 Properties. Butyric acid, when pure, is a colourless, transparent, and very mobile 
 liquid, having an odour suggestive both of vinegar and of rancid butter. It has a 
 very sour and burning taste, and attacks the skin like the strongest acids. It boils at 
 
 Y Y 2 
 
692 BUTYRIC ACID. 
 
 157 C. under 760 mm. pressure (Kopp), and distils without alteration. Its vapour- 
 density varies with the temperature ; at 261 C. it was found to be 37, corresponding 
 to 2 vols. The vapour is inflammable, and burns with a blue flame. The density 
 of the liquid acid is 0-9886 at 0C.; 0'9739 at 15; and 0-9675 at 25. It does 
 not solidify at 20, but in a mixture of solid carbonic acid and ether it crystallises 
 in plates. Butyric acid is soluble in all proportions in water, alcohol, and wood- 
 spirit. 
 
 Decompositions. 1. Butyric acid dissolves in sulphuric acid without alteration in 
 the cold ; at higher temperatures, the greater part distils off unchanged. 2. It also dis- 
 solves in nitric add in the cold ; by prolonged ebullition with nitric acid of specific 
 gravity T40, it is transformed into succinic acid : 
 
 C 4 H 8 2 + O 3 = C 4 H0* + H 2 0. 
 
 Butyric Succinic 
 
 acid. acid. 
 
 3. lodic acid does not act upon butyric acid. 4. Butyric acid is energetically attacked 
 by chlorine, with formation of hydrochloric acid and of dichlorobutyric acid, 
 C 4 H 8 CP0 2 . If the action of the chlorine be continued, the butyric acid is ultimately 
 converted into' tetrachlorobutyric acid, C 4 H 4 C1 4 2 . Iodine has scarcely any 
 action on butyric acid. 5. By the action of pen tac hloride of phosphorus, chloride of 
 tutyryl, C 4 H 7 OC1, oxychloride of phosphorus, and hydrochloric acid are formed: 
 
 C 4 H 7 OC1 + POCP + HCL 
 
 Butyric Chloride of 
 
 acid. butyryl. 
 
 6. With pentasulphide of phosphorus, it forms thiobutyric acid (p. 694). 
 
 + P0*. 
 
 Butyric acid. Thiobutyric 
 
 acid. 
 
 BUTYRATES. Butyric acid is monobasic, the butyrates being represented by the 
 general formula C 4 H 7 M0 2 = C 4 H 7 O.M.O. 
 
 When quite dry, they are inodorous; but when moist, they possess a strong odour of 
 butter. They are mostly soluble in water, and crystallisable. Many of them rotate 
 when thrown upon water. 
 
 Butyrate of Ammonium, C 4 H 7 (NH 4 )0 2 . A deliquescent salt, which gives 
 butyronitrile, C 4 H 7 N, when distilled with anhydrous phosphoric acid. 
 
 Butyrate of Ally U gee BuTYRIC ETHERS ( 696) 
 
 Butyrate of Amy I. \ 
 
 Butyrate of Barium. C 4 H 7 Ba0 2 -t- 2 aq. Obtained by neutralising butyric 
 acid with baryta-water. The filtered solution evaporated in the cold yields long 
 flattened prisms, which are quite transparent, and contain 2 at. water. They melt 
 at a temperature below 100 C., without any loss of weight, to a transparent liquid. 
 The salt dissolves in 2'27 pts. of water at 10, and rotates on the surface. When 
 butyrate of barium is crystallised from a hot concentrated solution, it contains 10 '5 
 per cent, of water = 1 at. water of crystallisation, its formula being C 4 H 7 Ba0 2 + aq. 
 
 Butyrate of Copper. C 4 H 7 Cu0 2 + H 2 0. According to Chevreul, and to Pelouze 
 and Gelis, this salt contains 2 at. water ; according to Lies-Bodart, 1 at. water. It 
 is obtained by the addition of a cupric salt to a solution of butyrate of potassium. 
 The bluish-green precipitate formed is crystallised from boiling water, which yields it in 
 crystals of the monoclinic or oblique prismatic system. By prolonged ebullition with 
 water, the salt is partially decomposed into subsalt and free butyric acid. By distilla- 
 tion at about 250 C., butyrate of copper is completely decomposed into a liquid which 
 appears to be pure butyric acid, a gas composed of equal volumes of carbonic oxide 
 and carburetted hydrogen, and a residue of finely divided metallic copper mixed with 
 carbon. When butyrate of copper is rapidly heated to a high temperature, there is 
 produced, along with other substances, a white crystalline body, which is cuprous 
 butyrate. A compound corresponding to Schweinfurt-green (p 15) is obtained by 
 mixing a solution of butyrate of copper with solution of arsenious acid. A yellowish- 
 green amorphous precipitate forms, which afterwards becomes crystalline, and exhibits 
 the pure green colour belonging to Schweinfurt-green. It is a double salt of arsenite 
 and butyrate of copper, C 4 H 7 CuO'.2AsCu0 2 . 
 
 Butyrate of Calcium. C 4 H 7 Ca0 2 (at 140C.). Obtained like the barium-salt. 
 Crystallises in delicate needles ; melts on being heated in its water of crystallisation, 
 which it gives off with tolerable facility. The dry salt, on being distilled, gives an oily 
 distillate, consisting principally of butyral and butyrone. This salt rotates when 
 thrown on water. It dissolves in 57 pts. of water at 15 but crystallises out so com- 
 
BUTYRIC ACID. 693 
 
 pletely when the solution is heated, that the whole becomes solid. On cooling, it again 
 becomes liquid. 
 
 Butyrate of Calcium and Barium. The aqueous solution of 2 pts. butyrate of cal- 
 cium, and 3 pts. butyrate of barium, deposits octahedrons of this double salt on spon- 
 taneous evaporation. 
 
 Butyrate of Iron. Iron does not decompose dilute butyric acid, but gradually 
 oxidises at the expense of a portion of the acid, the oxide combining with the remainder. 
 A yellowish basic salt which separates, appears to be soluble in a large quantity of 
 water. 
 
 Butyrate of Ethyl. See BUTYRIC ETHERS (p. 695). 
 
 Butyrates of Lead. The neutral salt, C 4 H 7 Pb0 2 , is obtained in fine silky needles 
 by abandoning the solution of lead-oxide in butyric acid to spontaneous evaporation over 
 oil of vitriol. The same salt is precipitated by butyric acid from a solution of neutral 
 acetate of lead, as a colourless very heavy oil, which solidifies after some time only. 
 Basic-salt, C 4 H 7 Pb0 2 .Pb 2 0. Alkaline butyrates give a copious white precipitate with 
 solutions of subacetate of lead. When a mixture of acetic and butyric acids is satu- 
 rated with lead-oxide, rose coloured crystals of basic butyrate of lead are formed. 
 These are decomposed by the carbonic acid of the air, but are held in solution by the 
 acetate which adheres to them. 
 
 Butyrate of Magnesium. 2(C 4 H 7 Mg0 2 ) + 5aq. Beautiful white laminae, like 
 crystallised boric acid. The water of crystallisation is easily expelled. 
 
 Mercurous Butyrate. White shining scales, like mercurous acetate. 
 
 Butyrate of Methyl. See BUTYRIC ETHERS (p. 696). 
 
 Butyrate of Potassium. C 4 H 7 K0 2 . Carbonate of potassium is neutralised 
 with aqueous butyric acid, and the solution evaporated. Crystallises in indistinct 
 cauliflower-like groups. Very deliquescent; dissolves in '8 of water at 15 C. Ro- 
 tates on water. There appears to be an acid butyrate of potassium. When butyrate 
 of potassium is distilled with an equal quantity of arsenious anhydride, there is ob- 
 tained, besides secondary products, an oily liquid blackened by reduced arsenic, and 
 smelling like alkarsin ; it is either alkarsin or the term corresponding to it in the 
 butyric series (p. 412.) 
 
 Butyrate of Sodium is like the potassium-salt, but less deliquescent. 
 
 Butyrate of Silver. C 4 H 7 Ag0 2 . Butyrate of potassium mixed with nitrate of 
 silver forms white shining scales, like acetate of silver. The salt does not deflagrate 
 when heated, but leaves metallic silver mixed with a little charcoal. 
 
 Butyrate of Strontium. C 4 H 7 Sr0 2 (dry). Long flat needles like the barium- 
 salt; fusible; soluble in 3 pts. of water. 
 
 Butyrate of Zinc. C 4 H 7 Zn0 2 . Aqueous butyric acid dissolves carbonate of zinc 
 at ordinary temperatures ; the filtered solution evaporated in vacuo leaves shining fusible 
 laminae. The aqueous solution is decomposed by repeated evaporation into basic salt 
 and free butyric acid. 
 
 Substitution-derivatives of Butyric Acid. 
 
 PIBROMOBUTYRIC Aero. C 4 H 6 Br 2 2 . Cahours (Ann. Ch. Phys. [3] xix. 495) ob- 
 tained an acid of this composition, by the action of bromine on citraconate or itaconate 
 of potassium, to which he gave the name bromotriconic acid. It is now commonly re- 
 garded as a brominated derivative of butyric acid, and as such finds its description 
 here. When bromine is gradually added, until slightly in excess, to a solution of 
 citraconate of potassium in 1| pts. of water, carbonic acid is evolved, and a heavy 
 yellowish oil is deposited, which is a mixture of two substances, the one an acid, the 
 other a neutral oil. This is washed with water and treated with potash, which dis- 
 solves out the acid, and leaves the neutral oil unchanged. On adding dilute acid to 
 the alkaline solution, the acid is deposited sometimes as a heavy yellowish oil, some- 
 times in fine crystalline needles : the two substances are identical in composition. 
 
 The oily acid has a slight amber colour ; it has a peculiar odour, feeble at ordinary, 
 but irritating at higher temperatures. It is much heavier than water, in which it is 
 slightly soluble ; it is quite soluble in alcohol and in ether. It is partially decom- 
 posed by distillation, with formation of hydrobromic acid fumes, and leaves a carbo- 
 naceous residue. Sometimes the oily acid changes spontaneously into a mass of 
 crystals. It is attacked by citric acid with disengagement of red fumes. Strong 
 potash-ley dissolves it, disengaging a peculiar odour, after which the addition of acid 
 no longer precipitates an oil. 
 
 The oily acid forms with ammonia an acid salt, C 4 H 5 (NH 4 )Br 2 2 .C 4 H 6 Br 2 2 which 
 crystallises in yellowish white unctuous scales, easily soluble in water and in alcohol. 
 The silver-salt, C 4 H 8 AgBr 2 2 , is obtained by adding nitrate of silver to a solution of 
 
 YY 3 
 
694 BUTYRIC ANHYDRIDE. 
 
 the ammonia-salt, as a curdy precipitate, which, after standing some time, unites into a 
 pitchy mass. 
 
 Dibromobutyric Ether. C 4 H 5 (C 2 H 5 )Br 2 2 , is obtained with difficulty. A solution 
 of the acid in absolute alcohol is saturated at 70 80C. with hydrobromic acid gas ; 
 the solution is distilled ; the distillate is mixed with water, and the resulting precipitate 
 is washed first with dilute carbonate of soda, then with pure water, and finally dried 
 over oil of vitriol. It emits an irritating odour when heated, and has a sharp taste. 
 
 Further experiments are required to prove that Cahours' bromotriconic acid is the 
 true dibromobutyric acid, and it is to be regretted that its discoverer should not have 
 fully cleared up this point. Cahours obtained the following results in attempting to 
 obtain dibromobutyric acid directly. Bromine was added to a solution of butyrate of 
 potassium, until a few drops of a brominated acid were precipitated ; the whole was 
 then evaporated to dryness, dissolved in alcohol, filtered, and a few drops of sulphuric 
 acid added, which precipitated an acid different from butyric acid and less odorous, 
 but soluble in water and in alcohol. It did not appear to be identical with bromo- 
 triconic acid. 
 
 DICHLOROBUTYKIC Aero. C 4 H 6 C1 2 2 . (Pelouze and Gel is, Ann. Ch. Phys. [3] 
 x. 447.) The best method of preparing this acid is to pass dry chlorine gas in bright 
 sunshine, through about 40 grm. of butyric acid, placed in a Liebig's bulb-apparatus. 
 At first, the absorption is very rapid ; subsequently, hydrochloric acid is disengaged, 
 and the liquid assumes a yellowish-green colour. The absorption becomes slower and 
 more difficult, and the current of chlorine must be continued for several days before 
 it ceases to be absorbed. Dry carbonic acid gas is now passed through it, at a tem- 
 perature of 80 100 C. to expel the hydrochloric acid : the residue is dichlorobu- 
 tyric acid. 
 
 It is a colourless viscid liquid, heavier than water, and having a peculiar odour, some- 
 what like that of butyric acid. It is insoluble in water, but entirely soluble in alcohol. 
 It can be distilled to a great extent without alteration, but a portion always decom- 
 poses. It burns with a green-edged flame. 
 
 Its potassium-, ammonium-, and sodium-salts are soluble. Its silver-salt is sparingly 
 soluble. 
 
 Dichlorolutyric EtJicr, C 1 H 5 (C 2 H 5 )C1 2 ? , is prepared by gently heating an alcoholic 
 solution of dichlorobutyric acid with sulphuric acid. An oily compound ether having 
 an ethereal odour, is deposited, which is washed with water and distilled. 
 
 TETRACHLOROBUTYEIC AGED. C 4 H 4 C1 4 2 . (Pelouze and Gr61is, loc. cit.) This 
 acid is produced by the continued action of chlorine upon butyric acid in bright sun- 
 shine : the chlorobutyric acid at first formed is ultimately converted into a white, 
 solid, crystalline mass, which when pressed between paper, and crystallised from ether, 
 is obtained in the form of white oblique, rhombic prisms, which melt at 140 C., distil 
 without decomposition, and smell like butyric acid. Its silver-salt, C 4 H H AgCl 4 2 , is 
 sparingly soluble. 
 
 Tetrachlorobutyric Ether. C 4 H 8 (C 2 H 5 )C1 4 2 . In a solution of tetrachlorobutyric 
 acid in several times its bulk of alcohol, the addition of oil of vitriol immediately 
 produces a crystalline mass, which melts at a gentle heat, and separates into two layers, 
 the heavier of which is tetrachlorobutyric ether. It has an ethereal odour, and burns 
 with a green flame, giving off white fumes of hydrochloric acid. 
 
 TmoBUTTEic ACID, C 4 H 8 OS = HS. Sulphobutyric acid. (Ulrich, Ann. 
 
 Ch. Pharm. cix. 280.) This acid is produced by the action of pentasulphide of phos- 
 phorus on butyric acid (p. 691). The substances in equivalent quantities are distilled 
 together in a flask furnished with an inverted condensing apparatus, the action, which 
 is violent at first, being assisted towards the end by gentle heating. After it has con- 
 tinued for several hours, the mixture is distilled, and the reddish liquid, which contains 
 butyric acid and dissolved sulphur, as well as thiobutyric acid, is subjected to fractional 
 distillation, the thiobutyric acid passing over at 130 C. It is a colourless liquid, of 
 almost insupportable and persistent odour; boils at 130 C. ; is sparingly soluble in 
 water, readily in alcohol, and dissolves sulphur with yellowish colour. With acetate of 
 lead, it forms a bulky white precipitate of thiosulphate of lead, C 4 H 7 PbOS, soluble in 
 a large quantity of hot water, also in hot alcohol, and separating on cooling, in small 
 colourless crystals. The salt decomposes readily, with separation of sulphide of lead. 
 
 E.A. 
 
 BUTYRIC ANHYDRIDE. Anhydrous Butyric Acid. C 8 H 14 3 = QQ - 
 
 (Gerhardt, Ann. Ch. Pharm. Ixviii. 127.) The formation of this body is analogous 
 to that of the organic anhydrides in general, that is to say, it is formed by the action 
 of chloride of butyryl on an alkaline 1 butyrate. 
 
BUTYRIC ETHERS 695 
 
 It is prepared by treating 4 pts. of dry butyrate of sodium with 2 pts. of oxychloride 
 of phosphorus, the oxychloride being added drop by drop to the butyrate, as in the pre- 
 paration of acetic anhydride. The reaction consists of two stages, the first being the 
 formation of chloride of butyryl and phosphate of sodium : 
 
 3C 4 H 7 Na0 2 + POOP = Na 8 P0 4 + 3C 4 H 7 OC1, 
 
 and the second, the formation of butyric anhydride by the action of this chloride 
 on another portion of butyrate of sodium. When the reaction is complete, the mass is 
 distilled, and the distillate redistilled over butyrate of sodium, in order to convert any 
 remaining chloride of butyryl. The distillate from this is finally rectified, those parts 
 only being collected which boil at 190 0. ; the portions which pass over below this point 
 contain butyric acid, the formation of which cannot well be avoided, from the deli- 
 quescent nature of the butyrate of sodium. 
 
 Like acetic anhydride (p. 20), butyric anhydride may be prepared by the action of 
 benzoic chloride on butyrate of sodium. Five pts. of benzoic chloride are mixed with 
 8 pts. of butyrate of sodium in a retort, and distilled, and the distillate rectified, at 
 first over butyrate of sodium, and then alone. 
 
 Butyric anhydride is a colourless, very mobile, and highly refracting liquid, of 
 specific gravity 0-978 at 12-5 C. Its odour is very strong, but not disagreeable, and 
 rather resembling butyric ether than butyric acid. It boils at 190, and its vapour- 
 density has been found to be 5-38. Exposed to the air, it gradually attracts moisture, 
 and is converted into butyric acid. Poured into water, it does not dissolve like butyric 
 acid, but rises to the surface as a colourless oil. In contact with aniline, it becomes 
 Seated, and forms butyranilide (phenylbutyramide) : 
 
 (C 4 H 7 0) 2 + 2(KH 2 .C 6 H 5 ) = 2(KH.C 8 H 5 .C 4 H 7 0) + H'O. E. A. 
 
 BUTYRIC ETHERS. These compounds are formed from butyric acid by the 
 substitution of 1 at. of an organic radicle, such as ethyl, methyl, &c. for 1 at. of hy- 
 drogen. They are for the most part formed by the direct action of butyric acid on 
 the alcohols. 
 
 BUTYRATE OF AIXYL. C'H^O 2 = C 4 H 7 (C 3 H 5 )0 2 . Obtained by distilling butyrate 
 of silver with iodide of allyl. After rectification, it is a colourless oily liquid, lighter 
 than water, soluble in ether, smelling like butyrate of ethyl, and boiling at about 
 140 C. Heated with potash, it yields allyl-alcohol and butyrate of potassium. 
 (Cahours and Hofmann, Phil. Trans. 1857, p. 555.) 
 
 BUTYRATE OF AMY!,. C 9 H I8 O 2 = C 4 H 7 (C 5 H n )0 2 , is a liquid boiling at 17'6 C. 
 (Delffs). Specific gravity 0'852 at 15. Index of refraction = 1-402. 
 
 BUTYRATE OF ETHYL. Butyric Ether. C 6 H 12 2 = C 4 H 7 (C-'H 5 )0 2 . This ether is 
 readily produced by the action of butyric acid on alcohol, sulphuric acid being like- 
 wise present. It is also formed, according to Berthelot, by distilling a mixture of 
 1 pt. common ether, 3 pts. butyric acid, and 7 to 8 pts. sulphuric acid ; but the dis- 
 tillate contains a large quantity of free butyric acid. To prepare it, 2 pts. butyric acid 
 are dissolved in an equal weight of strong alcohol, and 1 pt. sulphuric acid is added 
 to the mixture. The liquid becomes heated, and butyric ether immediately rises to 
 the surface ; but to complete the transformation, it is necessary to heat the mixture 
 for a short time to about 80 C. The butyric ether is then decanted, shaken up several 
 times with water, finally with addition of chalk and chloride of calcium, then dried 
 over chloride of calcium and distilled. 
 
 Butyrate of ethyl is a transparent, colourless, very thin liquid, of specific gravity 
 0-90193. Boils at 119 C., under a pressure of 07465 mm. Vapour-density = 4'04. 
 It has an agreeable odour, like that of pine-apples, and a sweetish taste, with bitter 
 after-taste. It is very sparingly soluble in water, but dissolves in all proportions in 
 alcohol and in ether. It is slowly decomposed by potash, into butyrate of potassium 
 and alcohol. 
 
 To the presence of small quantities of butyric ether, the peculiar flavour of pine- 
 apples, melons, and some other fruits, is due. Its formation in the fruit receives an 
 obvious explanation, from the readiness with which the saccharine matters present 
 pass on the one hand, into lactic and butyric acids, and on the other, into alcohol. 
 The pine-flavoured rum, known as pine-apple rum, owes its flavour to the presence 
 of this ether. When freshly distilled from molasses, rum has but little flavour, but 
 this comes out on keeping, owing to the fact that a small quantity of butyric acid 
 contained in it, gradually combines with the alcohol to form ether. 
 
 A solution of butyric ether is very extensively used in perfumery, and in confec- 
 tionery, under the, name of pine-apple oil. It is prepared for this purpose by the fol- 
 lowing process. Butter is saponified by a strong solution of potash-ley; the f"-' 
 dissolved in very little absolute alcohol, and to the solution is added f> 
 
 Y Y 4 
 
696 BUTYRINS. 
 
 alcohol and sulphuric acid, until a strongly acid reaction is set up. The whole is then 
 distilled, heat being applied as long as anything comes over with a fruity odour. 
 
 BUTYBATE OF ETHYLENE, C !0 H 18 4 = ^ C *" 2 > is obtained by heating bro- 
 
 mide of ethylene for several days to 100 C. with butyrate of silver and a little free 
 butyric acid, exhausting the product with ether, and distilling fractionally : 
 
 2(C 4 H'O.Ag.O) + C^Br 2 = 2AgBr + (C 4 H 7 0) 2 .(C 2 H 4 )".0 2 . 
 
 It is a colourless liquid, of specific gravity 1-024 at C. ; smells like butyric acid, and 
 boils at 239 to 241 C. (A. Wurtz, Ann. Ch. Phys. [3] Iv. 400.) 
 
 BUTYBATE OF GrLYCEBYL. See BuTYBINS. 
 
 BUTYBATE OF METHYL. C 5 H 10 2 = C 4 H 7 (CH 3 )0 2 . A mixture of 2 pts. butyric 
 acid with 1 pt. of wood-spirit and 1 pt. of strong sulphuric acid, becomes heated and 
 separates into two layers, the upper of which is butyrate of methyl. In order that 
 the transformation may be complete, it is well to agitate the mixture, and even to main- 
 tain it for some time at a temperature of from 50 80 C. The product is purified 
 like the ethyl-compound. 
 
 Butyrate of methyl is a transparent colourless liquid of specific gravity 1-0293. 
 Boils at 102 C. Specific heat is 0-4918. Latent heat of vapour, 87'33. Vapour- 
 density, 3-52. It has a pleasant odour, somewhat resembling that of pine-apples. 
 It is scarcely soluble in water, but perfectly soluble in alcohol and in ether. E. A. 
 
 BITTYRXDXCT. This name was given by Berthelot to a compound formed from 
 butyric acid and glycerin, to which he at first assigned the formula C 14 H 26 7 
 ( = 2C 4 H 8 2 + 2C 3 H 8 3 - 3H 2 0), but which he afterwards found to be identical 
 with dibutyrin (p. 695). 
 
 BITTYRIWS. (Berthelot, Ann. Ch.Phys. [3] xli. 261.) By the direct action of 
 butyric acid on glycerin, a series of compounds analogous to the acetins is obtained. 
 They are monobutyrin, C 7 H 14 4 , dibutyrin, C U H 20 5 , and tributyrin, C 15 H 26 8 . They 
 contain the elements of glycerin and butyric acid, minus those of water. Their forma- 
 tion may be thus expressed : 
 
 C 3 H 8 3 + C 4 H 8 0' - H 2 = C 7 H 14 0* 
 
 Glycerin, Butyric Mono- 
 
 acid. butyrin. 
 
 C 3 H 8 3 + 2(C 4 H 8 2 ) - 2H 2 = C n H 20 5 
 
 Glycerin. Butyric Dibutyrin. 
 
 = 3(C 4 H 8 O 2 ) - 3H 2 = C' 5 H 26 6 
 
 Glycerin. Butyric Tributyrin. 
 
 acid. 
 
 Viewing glycerin as a triatomic alcohol, we may consider the butyrins as glycerin 
 
 O 3 , in which 1, 2, or 3 at. of hydrogen are replaced by the radicle butyryl, 
 
 C 4 H 7 0. 
 
 The butyrins are decomposed by alkalis, and also by the alkaline earths, baryta and 
 lime, with formation of a butyrate and elimination of glycerin. Dissolved in alcohol 
 and treated with hydrochloric acid, they yield butyric ether and glycerin. 
 
 (C'HT) 
 MONOBUTYBIN, C 7 H 14 4 = HHO 3 . This body is formed, but only in small 
 
 C 4 H 7 0) 
 
 proportions, by exposing a mixture of butyric acid with excess of glycerin, to the 
 action of the sun or of diffused daylight for several months. It is also obtained by 
 heating butyric acid with glycerin to a temperature of 200 C. for three hours, care 
 being taken not to exceed this temperature. It is a colourless, neutral, odoriferous, 
 oily liquid, having an aromatic and bitter taste, without any after-taste. At 40 C., 
 it remains liquid, and as mobile as at ordinary temperatures. It rapidly acidifies when 
 exposed to the air. 
 
 (C 3 H 5 )'") 
 DIBTTTYBIN, C n H 2e 5 = H VO 3 . Whenever in the preparation of niono- 
 
 (C 4 H 7 0) 8 ) 
 
 butyrin, the temperature exceeds 220 C 1 ., some dibutyrin appears to be formed, but it 
 is best prepared by heating a mixture of glycerin and butyric acid to 275 for several 
 hours. It is a colourless, neutral, oily, odoriferous liquid, of specific gravity TO 31. It 
 volatilises at 320 without perceptible alteration. Cooled down to 40, it remains 
 liquid, but its fluidity diminishes. By aqueous ammonia, it is decomposed, with 
 formation of butyramide. 
 
BUTYRITE BUTYROLACTIC ACID. 697 
 
 TBIBUTYEIN, C 15 H 26 6 = , 3 o s . This substance is formed by heating 
 
 butyrin with 10 to 15 times its weight of butyric acid to 240 C. for four hours. It is 
 a neutral, oily liquid, with an odour analogous to that of the preceding compounds, 
 and a pungent taste, with irritating aftertaste. It is very soluble in alcohol and 
 ether, but insoluble in water. 
 
 Natural Butyrin. A butyrin which is probably tributyrin, is contained in small 
 quantities in butter, along with caproin, caprin, olein, and margarin. It has not been 
 obtained free from these substances. According to Pelouze and Grelis, this compound 
 may be prepared artificially by gently heating a mixture of butyric acid, glycerin, and 
 concentrated sulphuric acid. On adding a large quantity of water, a slightly yellowish 
 oil separates, which must be washed with water, in which it is insoluble. It is soluble 
 in all proportions in alcohol and ether, from which solutions it is separated by the 
 addition of water. Saponified by potash, it yields glycerin and butyrate of potassium. 
 It has not been obtained pure, and is most probably a mixture of the butyrins above 
 described. E. A. 
 
 BUTYRITE. A compound formed from butyric acid and mannite in the same 
 manner as the butyrins are formed from butyric acid and glycerin. Its properties 
 have not been described. (Berth elot, Compt. rend, xxxviii. 688.) 
 
 The same name is sometimes applied to bog-butter (q. v.} 
 
 BirrirROCHIiORIttrXftRXXr. By the action of hydrochloric acid on a mixture 
 of butyric acid and glycerin, a product (first observed by Pelouze) is obtained, which, 
 according to Berth elot (Ann. Ch. Phys. [3] xli. 303), is a mixture of the compounds 
 C 3 H G (C 4 H 7 0)C10 2 and C 3 H 5 (C 4 H 7 0)CFO, that is to say, of chlorhydrin (C S H 7 C10 2 ) 
 and dichlorhydrin (C 3 H 6 C1 2 0), in each of which 1 at. H is replaced by butyryl. No 
 method of separating these two compounds has yet been devised. 
 
 BlTTYROIiEIC ACID. Bromeis (Ann. Ch. Pharm. xlii. 63) stated that butter 
 contains an oily acid resembling oleic acid in most respects, but differing from it in 
 not yielding sebacic acid by dry distillation. Bromeis assigned to this acid the for- 
 mula C 34 H 30 0*.HO. It appears, however, from the experiments of Gottlieb, that it 
 is really identical with oleic acid, and exhibits the characters observed by Bromeis 
 only after it has been considerably altered by exposure to the air. 
 
 BUTYXtOX.XMXXODXC ACID. See BOG-BATTER (p. 617). 
 
 (C 3 H 4 0)") 
 
 BUTYROX.ACTXC ACXX>. C 7 H 12 4 = C 4 H 7 O> O 2 . This acid, which is 
 
 H) 
 
 derived from lactic acid, (C 3 H 4 0)".H 2 .0 2 , by the substitution of 1 at. butyryl for 1 at. 
 hydrogen, has not yet been obtained in the free state; but Wurtz (Compt. rend. 
 xlviii. 1092) has obtained its ethyl-salt, (C 3 H 4 0)".C 4 H 7 O.C 2 H 5 .0 2 , by digesting chloro- 
 lactate of ethyl with an alcoholic solution of butyrate of potassium in the water-bath 
 for several days, then filtering to separate chloride of potassium, treating the filtrate 
 with chloride of calcium, and rectifying : 
 
 (C 3 H 4 0)".C 2 H 5 .C1.0 + C 4 H 7 O.K.O = KC1 + (C 3 H 4 0)".C 4 H 7 O.C 2 H*.0\ 
 
 Chlorolactate of ethyl. Butyrate of Butyrolactate of ethyl. 
 
 potassium. 
 
 It is an oily liquid, of specific gravity 1*024 at C., having an odour something like 
 that of butyric acid, insoluble in water, soluble in alcohol, and boiling between 200 
 and 210 C. The formation and constitution of this compound tend strongly to sup- 
 port the opinion that lactic acid is dibasic. (See LACTIC Aero.) 
 
 BtTTTTROWE. C 7 H 14 0. This body is the acetone or ketone of the butyric series, 
 and is, therefore, homologous with acetic acetone. It represents butyral, in which 1 at. 
 of hydrogen in the radicle is replaced by trityl : 
 
 C 4 H 7 0) C 4 H 6 (C 3 H 7 )0; 
 
 H { ' H 
 
 Butyral. Butyrone. 
 
 Its formation is analogous to that of its homologue, acetone. Butyrate of calcium 
 carefully distilled in small portions is decomposed into butyrone and carbonate of 
 calcium : 
 
 2(C 4 H 7 Ca0 2 ) = Ca'CO 3 + C 7 H 14 0. 
 
 Butyrate of Carbonate Butyrone. 
 ca'lcium. of calcium. 
 
 But when larger quantities are decomposed, the results are not so precise. The crude 
 product is composed of at least four substances, butyral, butyrone, and two other sub- 
 stances of the ketone series. The butyrone is obtained pure by rectification, those 
 parts being collected which boil at 140 145 C. and these are again rectified, until 
 a product of constant boiling point is obtained. 
 
698 BUTYRONE BUTYRYL. 
 
 Butyrone, when pure, is a colourless limpid liquid, having a peculiar penetrating 
 odour, and density = 0-83. It boils at 144 C., and its vapour-density lias been found 
 to be 4-0, which corresponds to two volumes for the formula C 7 H 14 0. Surrounded 
 by a mixture of solid carbonic acid and ether, it solidifies to a crystalline mass. It is 
 insoluble in water, but quite soluble in alcohol. It burns with a luminous flame. It 
 immediately takes fire in contact with chromic acid. It is energetically attacked by 
 nitric acid, with formation of nitropropionic acid, C 3 H 5 (N0 2 )O 2 , and of an ethereal 
 liquid, which is probably butyrate of trityl, C 4 H 7 (C 3 H 7 )0 2 . 
 
 Distilled with pentachloride of phosphorus, butyrone yields a compound, C 7 H 13 C1, 
 which Chancel terms chlorobutyrone. It is a colourless liquid, of penetrating odour, 
 lighter than water, and insoluble therein. It boils at 116 C. Its alcoholic solution 
 does not cloud nitrate of silver. 
 
 From the crude product of the distillation of butyrate of calcium, two substances with 
 definite boiling points may be separated by treating the crude distillate with acid sul- 
 phate of sodium, to remove butyral and butyrone, and subjecting the remaining liquid 
 to fractional distillation. One of these boils at 180 C., and has the specific gravity 
 0-827. It has the formula C 8 H I6 O 7 , which is thatof methyl-butyrone, C 7 H 13 (CH 3 )0, 
 or methyl-oenanthy 1, CH 8 .C 7 H I3 0. The latter view of its composition is suggested 
 by the fact that it yields oenanthic acid when oxidised by nitric acid. The other com- 
 pound boils at 222 C., and is a pale yellow liquid, which becomes solid at 12 C. Its 
 composition is C 11 H 22 0, which would correspond to tetryl-butyrone, C 7 H 13 (C 4 H 9 )O, 
 or tetryl-cenanthyl, C 4 H 9 .C 7 H 13 0. It appears to yield butyric and oenanthic acids 
 by oxidation. (Limpricht, Ann. Ch. Phann. cviii. 183.) 
 
 According to Friedel (Ann. Ch. Pharm. cviii. 125), the crude liquid obtained by the 
 distillation of butyrate of calcium, contains, amongst other products, ethyl-butyryl, 
 Q6jji2Q _ C 2 H S .C 4 H 7 0, a colourless liquid having a biting taste, an aromatic odour 
 like that of butyrone, specific gravity = 0'833 at C., and vapour-density = 3 -5 8, 
 and a much smaller quantity of m ethyl-butyryl, C 5 H 10 = CH S .C 4 H 7 0, of specific 
 gravity 3*827 at C., and vapour-density 3'13. ' E. A. 
 
 BUTYRONTTRIC ACID. This name has been applied to the product of the 
 action of nitric acid on butyrone. 
 
 BUTYROWITRII.E or CYANIDE OP TRITYI,. C 4 H 7 N = C 3 H 7 .CN. 
 This body is best prepared by distilling butyrate of ammonium or butyramide with 
 anhydrous phosphoric acid : 
 
 C 4 H"N0 2 - 2H 2 = C 4 H 7 N. 
 
 Butyrate of Butyro- 
 
 ammonium. nitrite. 
 
 It is a transparent colourless oil, of specific gravity 0795 at 12-6 C., and boiling at 
 118-5. It has an agreeable aromatic odour resembling that of bitter-almond oil. It 
 dissolves in boiling potash, with evolution of ammonia and formation of butyrate of 
 potassium : 
 
 C 4 H 7 N + KHO + H 2 = C 4 H 7 KO + NH 3 . 
 
 Butyro- Butyrate of 
 
 uitrile. potassium. 
 
 E.A, 
 
 BUTYRUXVI AUTIMOWII. A name applied to trichloride of antimony, on 
 account of its buttery consistence and fusibility. Other chlorides of like consistence 
 have also received similar names, e. g. Butyrum stanni, Butyrum zinci, &c. 
 BUTYRUREID. Syn. of BuTYRYL-UREA. 
 
 BTTTYRYIi. C 4 H 7 0. The radicle of butyric acid and its derivatives. The fol- 
 lowing compounds of it are known : 
 
 Bromide of butyryl C 4 H 7 O.Br 
 
 Chloride of butyryl C 4 H 7 O.C1 
 
 Iodide of butyryl C 4 H 7 O.I 
 
 Hydride of butyryl (butyric aldehyde) C 4 H 7 O.H 
 
 Oxide of butyryl (butyric anhydride) 
 Hydrate of butyryl (butyric acid) 
 Butyryl-propyl (butyrone) 
 Butyryl-urea or butyral-urea 
 
 (C 4 H'0) 2 .0 
 C 4 H 7 O.H.O 
 C 4 H 7 O.C 3 H 7 
 N 2 (CO)".H 3 .C 4 H 7 0. 
 
 The name butyryl has likewise been applied to the hydrocarbon C 4 H 7 , sometimes 
 regarded as the radicle of butyric acid. 
 
 BROMIDE OF BUTYRYL, C 4 H 7 O.Br, is produced by the action of bromide of phosphorus 
 on butyric acid at 90 100 C., purified by washing with water and rectification. 
 (Bechamp.) 
 
 CHLORIDE or BUTYRYL. C'IFO.Cl This body, like its homologue, chloride of 
 

 BUXINE B YTOWNITE. 699 
 
 acetyl, is produced by the action of 1 at. oxychloride of phosphorus on 3 at. butyrate of 
 sodium : 
 
 3C 4 H 7 Na0 2 + POOP = 3C 4 H 7 OC1 + Na 3 P0 4 . 
 
 Butyrate of Oxychloride Chloride of Phosphate 
 
 sodium. of phosphate, butyryl. of sodium. 
 
 The powdered butyrate is gradually added to the oxychloride contained in a retort : 
 for if the oxychloride were at once poured on the butyrate, a large quantity of anhy- 
 drous butyric acid would be formed. The mixture is distilled, and the liquid distil- 
 late rectified over a small quantity of butyrate of sodium, the temperature being kept 
 as low as possible, in order to prevent the anhydrous acid formed during the rectifica- 
 tion from distilling over with the chloride. 
 
 Chloride of butyryl is a colourless, mobile, strongly refracting liquid, heavier than 
 water, and fuming slightly in the air. Its boiling point is 95. It has a pungent 
 odour like both butyric and hydrochloric acids. It is immediately decomposed by water 
 into hydrochloric and butyric acids : 
 
 C*H 7 OC1 -i- H 2 = C 4 H 8 2 + HC1. 
 
 Chloride of Butyric 
 
 butyryl. acid. 
 
 With butyrate of sodium it yields chloride of sodium and butyric anhydride : 
 
 C 4 H 7 OC1 + C 4 H 7 NaO = NaCl + C^H^O 3 . 
 "With ammonia it yields butyramide and hydrochloric acid : 
 
 C 4 H 7 OC1 + NH 3 = C 4 H 7 O.H 2 .N + HC1. 
 
 IODIDE or BUTYBYL, C 4 H 7 O.I, produced by distilling butyrate of potassium with 
 iodide of phosphorus, is a brownish liquid, which melts in contact with the air, and 
 boils between 146 and 148 C. (Cahours.) E. A. 
 
 BUT YRYX. -UREA. See CAEBAMIDE. 
 
 BUXINE. An alkaloid said to exist in all parts of the box-tree (Buxus semper- 
 virens.) According to Faur6 (J. Pharm. xvi. 428) it is obtained as an uncrys- 
 tallisable mass, by boiling the aqueous solution of the alcoholic extract of the bark 
 with magnesia, exhausting the resulting precipitate with alcohol, decolorising with 
 animal charcoal, and evaporating. According to Couerbe (J. Pharm. January 1854, 
 p. 51), it may be obtained in the crystalline form by treating the sulphate with nitric 
 acid, whereby an admixed resin is destroyed or rendered insoluble, and precipitating 
 by an alkali. 
 
 Buxine has a bitter taste and excites sneezing ; it blues reddened litmus-paper ; is 
 nearly insoluble in cold water ; dissolves readily in alcohol, sparingly in ether ; insoluble 
 in alkalis. It is decomposed by nitric acid. Its salts are more bitter than the base 
 itself, and yield a gelatinous precipitate with alkalis. The sulphate is said to form 
 crystalline nodules. 
 
 Trommsdorff (Tromm. N. J. xxv. [2] 66) obtained from box-leaves a substance 
 probably identical with Faure's buxine. 
 
 BYSSOXiXTE. A name applied to the fine capillary implanted crystals of acti- 
 nolite, found on the St. Grothard and in the Tyrol. 
 
 BYSSUS ItXYTXXiX. The bundle of threads by which the common muscle 
 (Mytilus edulis) adheres to other bodies, consists, according to Scharling (Ann. Ch. 
 Pharm. xli. 48), of a mass resembling horny tissue, containing a small quantity of fat. 
 According to Lavine (J. Chem. med. xii. 124) it contains the salts which occur in 
 sea- water. 
 
 BYTOWNITE. A granular massive mineral occurring in large boulders near 
 Bytown, Canada West. The grains have one perfect cleavage and indications of 
 another oblique thereto. Hardness = 6 to 6'5. Specific gravity 2*80 (Thomson) ; 
 2733 (Hunt). It has a greenish- white colour and vitreous lustre, pearly on the 
 cleavage surface. Translucent. According to Thomson (J. pr. Chem. viii. 489) it 
 contains 47'57 per cent silica, 29'65 alumina, 9'06 lime, 7'6 soda, 3'57 ferrous oxide, 
 0-2 magnesia, whence it appears to be a variety of barsowite (p. 517), the alumina being 
 partly replaced by ferric oxide and the lime by soda. T. S. Hunt (Sill. Am. J. [2] 
 xii. 213) regards it as a variety of anorthite. A dark bluish-green granular mineral 
 or rock from Perth, Canada, which has been called Bytownite, is considered by the 
 same chemist as a mixture of bytownite and hornblende. 
 
700 
 
 CABBAGE CACAO. 
 
 C 
 
 CABBAGE. (See BBASSICA.) Infusion of red cabbage, obtained by pouring hot 
 water on the leaves, is a convenient test for acids and alkalis. A certain quantity of 
 alkali, just sufficient to neutralise the acid in the juice, turns it blue ; any further 
 quantity changes the blue to green ; and acids turn it red. 
 
 C ABB ACrXXKTX:. A bitter principle, obtained from the cabbage-tree ( Creoffraga 
 inermis, or Or. jamaicensis\ also called Jamaicine (q. v.) 
 
 CABOCIiE. A mineral resembling red jasper or felsite, found in the diamanti- 
 ferous sand of the province of Bahia. It has a density of 3*14 to 3'19 ; scratches 
 glass slightly ; turns white before the blowpipe, but does not melt ; dissolves partially 
 in warm strong sulphuric acid, leaving a white earthy residue, which dissolves in the 
 acid at a higher temperature, and is precipitated therefrom by water. Dam our 
 (L'Institut. xxi. 78) found in the red massive mineral, phosphoric acid, alumina, lime, 
 baryta, ferrous oxide, and water. 
 
 CACAO. The seeds or leaves of the Theobroma cacao and other species of the 
 same genus (Nat. Ord. Sterculiaccce), natives of South America and the West Indies, 
 which are extensively cultivated in those countries, and in the tropical parts of Asia 
 and Africa, are remarkable for their nutritive properties, and yield the well-known 
 substances, cocoa and chocolate. They contain large quantities of fatty matter and 
 vegetable albumin, and about 2 per cent, of an organic base, theobromine, C 7 H 8 N'0 2 , 
 resembling caffeine. The ash is very rich in phosphoric acid. Shelled beans of good 
 quality exhibit, before roasting, the following composition per cent. : 52 cacao-butter, 
 20 albumin, fibrin, &c., 2 theobromine, 10 starch, 2 cellulose, 4 inorganic matter, and 
 10 water, besides small quantities of colouring matter and essential oil. (Pay en, 
 Traite de Pelouze et Fremy, vi. 529.) 
 
 Cacao-beans have also been analysed by Tuchen (Inaugural Dissertation, Got- 
 tingen, 1857 ; and by A. Mitscherlich (Der Cacao und die Chocolade, Berlin, 1859), 
 with the following results : 
 
 
 Tuchen. 
 
 Mitscherlich. 
 
 j^ 
 
 
 / 
 
 Guaya- 
 quil. 
 
 Suri- 
 nam. 
 
 Caracas. 
 
 Vara. 
 
 Marag- 
 nan. 
 
 ^X 
 
 Trinidad. 
 
 ^ 
 
 Guaya- 
 quil. 
 
 % 
 Caracas. 
 
 Theobromine 
 
 0-63 
 
 0-56 
 
 055 
 
 0-66 
 
 0-38 
 
 0-48 
 
 121-5 
 
 
 Cacao-red . 
 
 4-56 
 
 6-61 
 
 6-18 
 
 6-18 
 
 6-56 
 
 6-22 
 
 3-5 5 
 
 
 Cacao-butter 
 
 36-38 
 
 36-97 
 
 35-08 
 
 34-48 
 
 38-25 
 
 36-42 
 
 4549 
 
 46-49 
 
 Glutin 
 
 2-96 
 
 3-20 
 
 3-21 
 
 2-99 
 
 3-13 
 
 3-15 
 
 1318 
 
 
 Starch 
 
 0-53 
 
 0-55 
 
 0-62 
 
 0-28 
 
 0-72 
 
 0-51 
 
 1418 
 
 13-517 
 
 Gum . 
 
 1-58 
 
 0-69 
 
 1-19 
 
 0-78 
 
 0-63 
 
 0-61 
 
 
 
 Extractive matter 
 
 3-44 
 
 4M8 
 
 6-22 
 
 6-<;2 
 
 332 
 
 5-48 
 
 
 
 Humic acid 
 
 8-57 
 
 7"25 
 
 9'28 
 
 8-63 
 
 8-03 
 
 9-25 
 
 
 
 Cellulose 
 
 30-50 
 
 30-00 
 
 28-66 
 
 30-21 
 
 2977 
 
 29-86 
 
 , 5-8 
 
 
 Ash . 
 
 3-03 
 
 3-00 
 
 2-91 
 
 3-00 
 
 2-92 
 
 2-98 
 
 3-5 
 
 
 Water 
 
 6-20 
 
 6-01 
 
 5-58 
 
 5-55 
 
 5-48 
 
 4-88 
 
 5-6-6-3 
 
 
 Starch-sugar 
 
 
 
 
 
 
 
 
 
 
 
 
 
 0-34 
 
 
 Cane-sugar 
 
 
 
 
 
 
 
 
 
 
 
 
 
 0-26 
 
 
 
 98-38 
 
 99-02 
 
 99-48 
 
 9938 
 
 99 19 
 
 99-84 
 
 
 
 Mitscherlich' s results do not differ from those of Payen, more than might be ex- 
 pected in the analysis of different varieties ; those of Tuchen, which differ widely 
 from both the preceding, probably refer to the unshelled beans. 
 
 The starch of cacao-beans exhibits granules of peculiar form, quite distinct from 
 those of the cereals and leguminosse ; by this means, the flour of either of the latter 
 may be detected when used to adulterate chocolate. 
 
 The ash of the shelled beans has been analysed by Letellier (Pelouze et Frdmy, 
 loc. cit.\ and by Zedeler (Ann. Ch. Pharm. Ixxviii. 348), with the following results : 
 
 K 2 Na 2 Ca 2 Mg 2 SO 3 CO 3 P 2 5 3Fe 4 8 .P 2 5 Cl SiO 2 
 
 33-4 11-0 17-0 4-5 1-0 29'6 0-2 3'3 (Letellier). 
 
 37-14 1-23 2-9 16*0 1'5 1-2 39-6 0'17 17 (Zedeler). 
 
 The kernels of the theobroma are used as an article of nutriment, either in the 
 natural state, or prepared in various ways. The simplest and best form is that of the 
 seeds roughly crushed, termed cocoa-nibs, which, however, require two hours' boiling, 
 as, owing to the peculiar nature of the inner isccd-coating, which passes down into tiie 
 
CACHALAGUA CACOTHELINE. 701 
 
 substance of the cotyledons, the prolonged application of heat and moisture is necessary 
 to dissolve the contents. Flake-cocoa is merely the seeds crushed between rollers. To 
 prepare chocolate, the beans, after being carefully picked, to free them from mouldy or 
 worm-eaten ones, are gently roasted over a fire in an iron cylinder, with holes in the 
 ends to allow the vapour to escape. When the aroma begins to be well developed, the 
 process is considered complete. The beans are then turned out, cooled, and freed from 
 their husks by fanning and sifting. The husks, which often amount to 20 or 25 per 
 cent, of the beans, should not be thrown away, as they contain half their weight of 
 soluble or mucilaginous matter, which yields a tolerable nutriment. The seeds are 
 then converted into a paste, either by trituration in a mortar heated to 130 F., or more 
 generally by a machine impelled by steam, and the paste is put into moulds and sent 
 into the market ; it always improves by keeping. Sometimes the beans, before being 
 roasted, are left to rot or ferment in heaps, in order to separate the kernels from the 
 soft piilpy mass which surrounds them in the fruit. 
 
 The chocolate of different countries varies according to its mode of preparation, and 
 the ingredients contained in it. When the kernels alone are used, or only a little sugar 
 is added, the chocolate is called " Chocolat de sante." But vanilla, cloves, cinnamon, 
 and other aromatics, are frequently added; also rice, almonds, starch, &c. Simple 
 chocolate is mostly preferred in this country, the perfumed sorts in France, Italy, and 
 Spain, where the consumption is immense. (See Ure's Dictionary of Arts, Manufac- 
 tures, and Mines, i. ; also Penny Cyclopedia, art. THEOBROMA.) 
 
 Cacao-butter, or Cacao-fat, is extracted from the beans by pounding them in a slightly 
 heated mortar, till they are reduced to a pulp, then adding a small quantity of water, 
 and squeezing the pulp in a cloth between two plates of metal previously heated to the 
 temperature of boiling water. It has an agreeable taste and odour, is white, semi- 
 transparent, insoluble in water, soluble, especially with aid of heat, in alcohol, ether, 
 and oil of turpentine. It has the consistence of suet, melts at 30 C., but does not 
 resume the solid state till cooled to 23. It consists chiefly of stearin, with a little 
 olein. It is used more in France than in this country, for making soap, candles, and 
 pommade. The soap made from it must not be confounded with that made from 
 cocoa-nut oil, which is a very different product, obtained from the cocoa palm (Cocos 
 nuciferd]. 
 
 Cacao-red is the colouring matter of cacao-beans. It is separated by precipitating 
 the aqueous or alcoholic decoction of the beans with acetate of lead, and decomposing 
 the washed precipitate with sulphuretted hydrogen. The solution thus obtained is 
 neutral, has a bitter taste, and yields lilac or greyish precipitates with acetate of lead 
 and protochloride of tin ; dark green, or brown-green, with ferric salts ; and green of 
 various shades, or sometimes violet with ferrous salts ; the colour of the precipitate 
 varies in each case, according as the cacao-red in the solution is more or less mixed 
 with other substances. 
 
 The solution of cacao-red absorbs oxygen during evaporation, and becomes acid, the 
 colouring matter being in fact converted into a kind of tannic acid. This modified cacao- 
 red gives, for the most part, green precipitates with iron and lead salts ; that obtained 
 from Guayaquil cacao, gives pale reddish precipitates with acetate of lead and with 
 lime-water, reddish-white with sulphate of magnesium and ammonium. It is preci- 
 pitated by gelatin, whereas unaltered cacao-red is not. 
 
 The alteration produced by the roasting of cacao-beans, appears to affect the cacao- 
 red more than any of the other constituents. 
 
 CACHAXiAGTTA, or CANCHA X.AGUA, is the South American name of the 
 Chironia chilensis, a gentianaceous plant, which, according to Bley (Arch. Pharm. 
 xxxvii. 85), contains resin and a bitter principle. 
 
 CACKOIiOWG. A variety of OPAL (q. v.) 
 
 CACHOUTAifl-ixric. or CACHUTIC ACID. See CATECHU. 
 
 CACODYXi. See ARSENIDES OF METHYL (p. 403). 
 
 C ACOTHELIKTE. C 2 H 22 N 4 9 = C 20 H 22 (N0 2 ) 2 N 2 5 . A product of the decompo- 
 sition of brucine by nitric acid (p. 682). It partly separates in orange-yellow crystalline 
 flakes after the action has ceased, and an additional quantity may be obtained by pre- 
 cipitating the red liquor with alcohol. From a solution in water strongly acidulated with 
 nitric acid, it separates in yellow scales. It is but very sparingly soluble in boiling 
 water, still less in boiling alcohol, and insoluble in ether. When heated, it decomposes 
 suddenly, in the manner characteristic of nitro-compounds. Exposed to diffused light 
 in a stoppered bottle, it soon becomes dark brown on the surface. Potash dissolves it 
 easily, forming a yellowish-brown liquid. Ammonia dissolves it immediately, forming 
 a yellow liquid, which on boiling changes first to green, afterwards to brown. Caco- 
 theline unites with metallic oxides : with baryta, it forms a soluble compound, con- 
 
702 C ACOXENE CADMIUM. 
 
 taining 2C 20 H 22 N 4 9 .Ba 2 0. It combines also with acids, but the salts are decom- 
 posed by water. When dichloride of platinum is added to a solution of cacotheline 
 in hydrochloric acid, the liquid, after a few hours, yields a crystalline precipitate con- 
 taining 48 per cent, platinum = C 20 H 22 N 4 9 .HCl.PtCP. 
 
 When cacotheline is left for some hours in the red nitric solution in which it has 
 been formed, it changes into another body, which has the colour of chrome-yellow, is 
 insoluble in water, and explodes when heated. (Strecker, Compt. rend, xxxix. 52.) 
 
 CACOXENX. A native ferric phosphate, found in the Hrbeck mine, near 
 Zbiron in Bohemia, in radiated tufts of yellow or brownish-yellow colour, becoming 
 brown on exposure. Specific gravity = 3-38. Hardness = 3 4. Of the following 
 analyses, a and b are by von Hauer (Jahrb. geolog. Keichsanst. 1854, 67); c by 
 Richardson (Thomson's Mineralogy, i. 476) : 
 
 P 2 S Fe 4 8 H 2 Ca 2 Mg 2 SiO 2 
 
 a . . 19-63 47-64 32-73 = 100 
 
 b . . 25-74 41-46 32-83 . = 100 
 
 c . . 20-5 43-1 30-2 1-1 0-9 2'1 = 97'9 
 
 a and c agree nearly with the formula 2Fe 4 3 .P 2 5 + 12 aq., or 3/e 2 0.2/e 3 P0 4 + 12 aq. 
 The analysis b, which, however, is said by von Hauer to have been made with less pure 
 material, approaches more nearly to 3Fe 4 9 .2P 2 5 + 20 aq. Former analyses by 
 Steinmann, which showed 10 11 per cent, alumina, were doubtless made with impure 
 specimens. (Rammelsberg's Mineralchemie, p. 331.) 
 
 CACTUS. Vogel obtained from the flowers of Cactus speciosus, by extraction 
 with weak alcohol, 30 per cent, of a carmine-red dye, insoluble in ether and in ab- 
 solute alcohol. The petals, after the removal of this substance, yielded to a mixture 
 of alcohol and ether, from 5 to 10 per cent, of a scarlet substance. Both these colour- 
 ing matters are soluble in water. (J. Pharm. xxii. 664.) 
 
 F. Field (Chem. Soc. Qu. J. iii. 57) has analysed the ash of a species of cactus (not 
 named) growing in Chili. The fresh plant yielded 1-35, the dry plant 1679 per cent, 
 of ash, containing in 100 pts. 57'15 pts. of soluble and 4273 of insoluble salts. The 
 air-dried plant yielded 85*09 per cent, water. The composition of the ash per cent. 
 is: 7-83 K'O, 28-19 Na ? 0, 10-65 Ca 2 0, 775 Mg 2 0, 0'34 Mn 4 3 , 6-09 SO 3 , 16-49 SiO 2 , 
 6-40 P 2 5 , 1'38 phosphates of calcium, magnesium, and iron, and 14*87 NaCL 
 
 CADET'S FUMING XiXQUID. See ARSENIDES OF METHYL (p. 403). 
 
 CADIE-GUM. A very pure kind of gamboge, probably from Hebradendron cam- 
 
 CADMIUM. Symbol Cd. Atomic weight 56. Atomic volume in the gaseous 
 state = 1. 
 
 This metal is frequently found associated with zinc, and derives its name from cad- 
 mia fossilis, a denomination by which the common ore of zinc was formerly known. 
 It appears to have been discovered about the same time (1818) by Stromeyer (Grilb. 
 Ann.lx. 193) and by Hermann (ibid. lix. 95, 113; Ixvi. 274), but its more exact 
 investigation is due to Stromeyer. 
 
 Cadmium occurs in small quantity in several varieties of native sulphide, carbonate, 
 and silicate of zinc, viz. in the radiated blende of Przibram in Hungary, to the amount 
 of 2 or 3 per cent.; in the blende of Nuissiere, to the amount of 1-14 per cent.; 
 in silicate of zinc from Freiberg and from Derbyshire ; in carbonate of zinc from 
 Mendip ; in carbonate and silicate of zinc from the Cumberland mines ; in the zinc 
 ores of the Harz and of Silesia. The zinc flowers obtained as a secondary product in 
 the smelting of the Silesian ores, contain, according to Hermann, as much as 11 per 
 cent, of cadmium. Commercial English zinc frequently also contains cadmium. The 
 only pure native compound of cadmium is the sulphide called Grcenockitc, found at 
 Bishopstown in Renfrewshire. 
 
 Preparation. In the process of reducing ores of zinc, the cadmium which they 
 contain comes over among the first products of distillation, owing to its greater vola- 
 tility. It may be separated from zinc in an acid solution by sulphydric acid, which 
 throws down the cadmium as a yellow sulphide. This sulphide dissolves in concen- 
 trated hydrochloric acid, affording the chloride of cadmium, from which the cai'bonate 
 may be precipitated by an excess of carbonate of ammonia. Carbonate of cadmium is 
 converted by ignition into the oxide ; and the latter yields the metal when mixed with 
 one-tenth of its weight of pounded coal, and distilled in a glass or porcelain retort, at 
 a low red heat. 
 
 Properties. Cadmium is a white metal, with a slight tinge of blue. It has a 
 strong lustre, and takes a fine polish ; by exposure to the air, it gradually acquires a 
 whitish-grey tarnish. It has a compact texture and fibrous fracture, and easily crys- 
 tallises in regular octahedrons. It is soft, though harder and more tenacious than 
 
CADMIUM: ALLOYS CHLORIDE. 703 
 
 tin ; very flexible, and crackles like tin when bent ; very malleable and ductile. Its 
 specific gravity is, after fusion, 8'604, after hammering, 8'6944. Specific heat 0-05669 
 (Kegnault), 0'0576 (Dulong and Petit). Cadmium melts below a red heat, and 
 volatilises somewhat below the boiling point of mercury without emitting any par- 
 ticular odour. The density of its vapour as determined by experiment at 1040 C. is 
 3-94, referred to air as unity (Deville and Troost, Ann. Ch. Pharm. cxiii. 46). 
 Now the calculated value for a condensation to 1 vol. is found by multiplying the 
 atomic weight by the density of hydrogen = 56 x 0'0693 = 3*88. Hence cadmium- 
 vapour follows the usual law of condensation (p. 441). 
 
 Cadmium dissolves in hot hydrochloric or dilute sulphuric acid, taking the place of 
 the hydrogen in the acid ; but its best solvent is nitric acid. The bromide, iodide, 
 and many of the organic salts of cadmium, the acetate for example, are soluble in 
 water ; the rest, e. g. the carbonate, borate, phosphate, and arsenate, are insoluble in 
 water, and are obtained by precipitation. Most cadmium-salts are colourless ; they 
 have a disagreeable metallic taste and act as emetics. The solutions, even of the 
 neutral salts, redden litmus. Those cadmium-salts which are insoluble in water are 
 soluble in sulphuric, hydrochloric, or nitric acid, also in ammoniacal salts. 
 
 Cadmium, in nearly all its compounds with electro-negative elements, plays the part 
 of a monatomic radicle, the chloride being CdCl, the oxide Cd 2 0, &c. 
 
 CADMIUM, AIiIiOlTS OP- But few alloys of cadmium are known. 100 pts. 
 copper retain at a red heat 82*2 pts. cadmium, forming an alloy having nearly the com- 
 position CdCu 2 . It is very brittle, has a fine-grained scaly structure, and a yellowish 
 white colour. With mercury, cadmium forms a hard, brittle, silver-white amalgam, 
 which crystallises in octahedrons, and contains 21*7 per cent, cadmium = CdHg 2 . 
 100 pts. platinum retain at a red heat, 117'3 pts. cadmium = Cd 2 Pt. The alloy 
 is almost silver-white, very brittle, very fine-grained, and refractory in the fire. 
 (Stromeyer.) 
 
 CADMIUM, BROMIDE OP. CdBr. Cadmium absorbs bromine- vapour at 
 a heat near redness, forming white fumes of the bromide, which crystallises on cool- 
 ing, and when strongly heated sublimes in white nacreous laminae. The hydratcd 
 bromide, 2CdBr.H~0, obtained by dissolving the oxide or carbonate in hydrobromic 
 acid, forms white efflorescent needles, which give off half their water at 100 C., and 
 the rest, without melting, at 200. 
 
 Bromide of cadmium forms crystalline compounds with the bromides of potassium, 
 sodium, and barium. The barium-salt, CdBr.BaBr + 2 aq., forms large, shining, 
 colourless crystals, isomorphous with the corresponding chloride. A solution of the 
 bromides of cadmium and potassium in equivalent proportions, first yields crystals 
 containing 2CdBr.KBr + aq., afterwards crystals of CdBr.KBr; both compounds 
 resemble the corresponding double chlorides (C. v. Hauer, J. pr. Chem. Ixiv. 477 ; 
 Ixvii. 169). A solution of equivalent quantities of bromide of cadmium and bromide 
 of sodium yields the compound 2CdBr.NaBr + f aq. in small, shining, six-sided tables. 
 (Croft, Chem. Gaz. 1856, p. 121.) 
 
 CADMIUM, CHLORIDE OP. CdCl. A solution of oxide of cadmium in 
 hydrochloric acid yields a crystalline hydrated chloride, CdCl.H'O ; and this when 
 fused yields the anhydrous chloride in the form of a transparent, laminated, pearly 
 mass, which melts at a heat below redness, and sublimes at a higher temperature in 
 transparent micaceous laminse. 
 
 A solution of chloride of cadmium mixed with excess of ammonia yields, by spon- 
 taneous evaporation, ammoniochloride of cadmium, NH 3 .CdCl, or chloride of cadmam- 
 monium, NIFCd.Cl. A triammonio-chloride of cadmium, 3NH s .CdCl, is obtained by 
 exposing dry pulverised chloride of cadmium to the action of gaseous ammonia. It 
 gives off of its ammonia when exposed to the air, and is converted into the preceding 
 compound. (Croft, Phil. Mag. [3] xxi. 355.) 
 
 Chloride of cadmium forms crystalline compounds with the chlorides of many other 
 metals. These compounds, which have been particularly studied by C. v. Hauer 
 (J. pr. Chem. Ixiv. 477; Ixvii. 169; Jahresber. d. Chem. 1855, p. 392; 1856, p. 394; 
 Chem. Soc. Qu. J. viii. 250), crystallise, by evaporation from mixed solutions of the 
 component chlorides. The following have been obtained : 
 
 The ammonium-salt, NH 4 Cl.CdCl-f |aq., crystallises in slender needles ; the mother- 
 liquor yields by spontaneous evaporation, transparent shining rhombohedrons of 
 2NH'Cl.CdCl. 
 
 Potassium-salts. KC1.2CdCl + |aq. separates, by spontaneous or by more rapid 
 evaporation, from a solution of 12 at. chloride of potassium to 1 at. chloride of cad- 
 mium, in fine silky needles, which give off their water at 100 C., and at a higher 
 temperature melt and give off part of their chlorine. The mother-liquor, or a solution 
 of at least 3 at. chloride of potassium to 1 at. chloride of cadmium, yields by spon- 
 
704 CADMIUM: DETECTION. 
 
 taneous evaporation, the salt 2KCl.CdCl, in large limpid crystals, somewhat less (?) 
 soluble than the preceding. 
 
 Sodium-salt. NaCLCdCl + f aq. (air-dried.) Small, turbid, watery crystals, which 
 give off 1 at. water at 100 G., and the remainder at 150 160. 
 
 Barium-salt. BaCl.CdCl -H 2 aq. Separates from a solution of equivalent quantities 
 of the two chlorides, in large shining crystals, which are permanent in the air, lose 
 half their water at 100 C., the rest at 160, and at a red heat give off part of their 
 chlorine, and melt to a colourless liquid, which does not crystallise. According to 
 Rammekberg's determination, the crystals are monoclinic, the obliquely inclined axes 
 making an angle of 75 45'. Ratio of the clinodiagonal, orthodiagonal, and principal 
 axis = 0-8405 : 1 : 0*5128. Observed faces, ooP . ooPoo . (ooPoo) . +P.-P.OP. 
 (2P oo). Inclination of faces, oo P : oo P oo = 140 50' ; oo P : OP = 101 0' ; OP : + P = 
 137 40'. 
 
 Strontium-salt. SrC1.2CdCl + |aq. Crystallises from a solution of 1 to 2 at. chlo- 
 ride of cadmium and 1 at chloride of strontium in transparent, colourless, acuminated 
 crystals. 
 
 Calcium- salts. A solution of 3 at. chloride of calcium to 4 at. chloride of cadmium 
 deposits the salt CaC1.2CdCl + faq. in deliquescent bevelled prisms, arranged in 
 stellate groups. A hot concentrated solution of 2 at. chloride of cadmium and 1 at. 
 chloride of calcium deposits, on cooling, large deliquescent crystals of the salt 2CaCl. 
 CdCl + aq. 
 
 Magnesium-salts. A solution of 1 to 2 at. chloride of cadmium to 1 at. chloride of 
 magnesium yields MgC1.2CdCl + 6 aq. in large transparent crystals. From a solution of 
 2 at. chloride of magnesium to 1 at. chloride of cadmium, the salt 2MgCl.CdCl+ 12aq. 
 separates in deliquescent tabular crystals. 
 
 Manganese-salt. MnC1.5CdCl + 6aq. Crystallises from a solution of 2 at. chloride 
 of cadmium and 1 at. chloride of manganese, in pale rose-red or colourless prisms. 
 
 Iron-salt. FeC1.2CdCl + 6aq. Crystallises from a solution of equivalent quan- 
 tities of the two chlorides, in colourless prisms, which soon turn green and yellow by 
 exposure to the air. 
 
 Cobalt-salt. CoC1.2CdCl+ 6aq. Somewhat deliquescent prisms, of the colour of 
 chloride of cobalt. 
 
 Nickel-salts. NiC1.2CdCl + 6 aq. crystallises by spontaneous evaporation from a so- 
 lution containing the two salts in the required proportions, in dark green prisms ; and 
 the mother-liquor, or the original solution, if it contains a slight excess of chloride of 
 nickel, yields 2NiCl.CdCl -f 6 aq. in large, dark green, rhombic prisms. 
 
 Copper-salt. CuCLCdCl + 2aq. Crystallises from a solution containing equivalent 
 quantities, in slender shining prisms, grouped in tufts, green when moist, blue when 
 dry. 
 
 Chloride of cadmium forms double salts with the hydrochlorates of many organic 
 bases. Greville Williams (Chem. Gaz. 1855, 450) obtained the quinoline-salt, 
 C 9 H"N.HC1.2CdCl, as a hard crystalline mass ; and other compounds have been obtained 
 by J. Galletly (Ed. N. PhiL J. iv. 94), viz. : 
 
 Cinchonine-salt. C 20 H 2 'N'O.HCl. CdCl + i aq. 
 
 Morphine-salts. C 17 H 9 N0 3 .HC1.7CdCl + 2 aq., and C 17 H 9 N0 3 .HC1.2CdCl + f aq. 
 Narcotinc-salt. Semi-crystalline, sparingly soluble mass. 
 Nicotine-salt. C'H H N 2 .2HC1.5CdCL Crystallisable. 
 Lutidine-salt. C 7 H 9 N.HC1.3CdCl. Very soluble feathery crystals. 
 Piperine-salt. C 34 H 36 N 2 5 .2HC1.9CdCl+ 3 aq. Straw-yellow needles. 
 Strychnine-salt. C 21 H 22 N 2 2 .HCLCdCl. Sparingly soluble in water. 
 Toluidine-salt. 2(C 7 H 9 N.HCl).3CdCl + aq. Very soluble scales. 
 
 CADMIUM, DETECTION 1 AND ESTIMATION OF. 1. Blowpipe Re- 
 actions. All cadmium-compounds, when heated on charcoal in the inner blowpipe 
 flame with carbonate of sodium or cyanide of potassium, give a brown incrustation 
 of cadmic oxide. A little cadmium, in presence of zinc, may be detected by heating 
 the mixture with carbonate of sodium for an instant in the inner flame, when a slight 
 incrustation of cadmic oxide will be formed. Much longer heating is required for the 
 formation of zinc-oxide. With borax and microcosmic salt, cadmic oxide forms a bead 
 which is yellowish while hot, colourless when cool. 
 
 2. Liquid Reactions. Zinc immersed in a solution of a cadmic salt, throws down 
 metallic cadmium in dendrites. Sulphydric acid ffas, passed through cadmium- 
 solutions, even when a large excess of acid is present, precipitates the whole of the 
 cadmium in the form of sulphide, which has a lemon-yellow colour at first, but after- 
 wards becomes oi-ange-yellow. A similar effect is produced by alkaline sulphydratcs, 
 the precipitate being insoluble in excess. The hydrated sulphides of manganese, iron, 
 cobalt, and nickel, when recently precipitated, likewise throw down sulphide of cad- 
 
CADMIUM: ESTIMATION IODIDE. 705 
 
 mium from cadmic salts (Anthon, J. pr. Chem. x. 353). Caustic alkalis throw down 
 white hydrate of cadmium, very easily soluble in a slight excess of ammonia, but in- 
 soluble in potash or soda. Sulphydric acid likewise precipitates sulphide of cadmium 
 from the solution in excess of ammonia. The neutral and acid carbonates of ammo- 
 nium, potassium, and sodium throw down white carbonate of cadmium, insoluble in 
 excess of the alkaline carbonates. If the salt contains a large quantity of free acid, 
 the precipitate dissolves in excess of carbonate of ammonia, but not otherwise (Stro- 
 meyer). Phosphate of sodium throws down white phosphate of cadmium. Oxalic 
 acid and alkaline oxalates precipitate white oxalate of cadmium, insoluble in alkaline 
 oxalates, but easily soluble in ammonia. The white precipitate produced by ferro- 
 ci/anide of potassium, and the yellow precipitate produced by the ferricyanide, are 
 soluble in hydrochloric acid. The addition of hyposulphite of sodium and hydro- 
 chloric acid does not produce a precipitate of sulphide of cadmium ; neither is any 
 precipitate produced by chromic acid, succinic acid, alkaline benzoates, or tincture of 
 galls. 
 
 Cadmium is the only metal which forms a yellow sulphide insoluble in sulphide of 
 ammonium. 
 
 3. Quantitative Estimation. Cadmium is best precipitated from its solutions 
 by carbonate of sodium ; it is thereby obtained as a carbonate, which, by ignition, yields 
 the brown oxide containing 87'5 per cent, of the metal. 
 
 4. Separation from other Elements. From the metals of the second and fourth 
 groups, and from all non-metallic elements except selenium and tellurium, cadmium may 
 be separated by sulphuretted hydrogen ; from selenium, tellurium, and the metals of 
 Group 1, Subdivision A (p. 217), by the insolubility of its sulphide in sulphide of 
 ammonium. The sulphide is then dissolved by nitric acid, and the cadmium preci- 
 pitated by carbonate of sodium, as above. 
 
 From bismuth, lead, and mercury, cadmium may be separated by the solubility of its 
 oxide in ammonia, or of its cyanide in cyanide of potassium : from lead also by sul- 
 phuric acid, and from mercury by precipitating the latter in the metallic state by proto- 
 chloride of tin. From palladium, it is also separated by the solubility of its cyanide 
 in cyanide of potassium ; from silver, by precipitating that metal as chloride. From 
 copper, cadmium is separated by carbonate of ammonium, an excess of which re- 
 dissolves the copper and not the cadmium : or better, by treating the solution of the 
 two metals with excess of cyanide of potassium, which precipitates and redissolves 
 them both, and passing sulphuretted hydrogen through the liquid, whereby the cad- 
 mium is precipitated, while the copper remains dissolved. (See COPPER.) 
 
 5. Atomic Weight of Cadmium. Stromeyer found that 114-352 pts. protoxide 
 of cadmium, Cd 2 0, yielded 14-352 0; whence 14-352 : 100 = 16 : Cd 2 ; and Cd = 
 
 55-7. Dumas (Ann. Ch. Pharm. cxiii. 27), from the mean of six 
 
 L x 
 
 experiments on the quantity of nitrate of silver required to precipitate the chlorine 
 from chloride of cadmium, found for the atomic weight of cadmium, numbers varying 
 from 55'89 to 56-38. He regards 56 as very near to the true value. 
 
 CADMIUM, FLUORIDE OF, CdF, is deposited from the aqueous solution on 
 evaporation, in white, indistinctly crystalline crusts. It dissolves sparingly in pure 
 water, more readily in aqueous hydrofluoric acid. (Berzelius.) 
 
 C ADMIU1V!, IODIDE OP. Cdl. Prepared either in the dry way, or by digest- 
 ing cadmium with iodine and water. Crystallises in large, transparent, six-sided 
 tables, which are not altered by exposure to the air. It melts easily, and solidif es 
 again in the crystalline form ; gives off iodine at a higher temperature. Dissolves 
 readily in water and alcohol, and crystallises unchanged from the solutions. Sulphy- 
 dric acid slowly precipitates sulphide of cadmium from the aqueous solution. 
 
 Two ammonio-iodides of cadmium are known, viz. NH 3 .CdI, which is deposited in 
 small crystals from a solution of iodide of cadmium in hot aqueous ammonia ; and 
 3NH 3 .CdI, which is a white powder produced by gently heating iodide of cadmium in 
 ammonia-gas. (Kammelsberg, Pogg. Ann. xlviii. 153.) 
 
 Iodide of Cadmium and Potassium,^ Cdl.KI + aq. crystallises in confused octa- 
 hedrons from a solution of the two iodides in equivalent proportions. In like manner 
 are obtained: NH'I.Cdl + aq., apparently isomorphous with the potassium -salt ; 
 NaLCdl + 3aq. in deliquescent prisms; Bal.Cdl + | aq., also deliquescent; and 
 SrI.Cdl + 4aq. in large crystals, which deliquesce in moist, and effloresce in dry air. 
 (Croft, Chem. Gaz. 185.6, p. 121.) 
 
 CADiviitriVT, NTTRIDE OP. (?) When an electric current is passed through a 
 solution of sal-ammoniac, the positive pole being formed of cadmium, and the negative 
 pole of platinum, the latter becomes covered with a spongy, lead-grey mass, which, 
 after washing and drying, has a density of 4-8 ; 5 grains of it gave off when heated, 
 
 VOL. I. Z Z 
 
706 CADMIUM : OXIDE CADMIUM-ETHYL. 
 
 0-18 to 0-25 cub. in. of nitrogen gas free from hydrogen, and left a yellowish-green 
 residue, containing globules of cadmium. (Grove, Phil. Mag. [3] xix. 99.) 
 
 CADMIUM, OXIDES OF. Cadmium forms two oxides, viz. a protoxide, Cd 2 0, 
 and a suboxide, Cd 4 0. The protoxide dissolves in acids without evolution or absorp- 
 tion of oxygen, and forms salts of corresponding composition : c. g. the sulphate, Cd 2 S0 4 , 
 the nitrate CdNO 3 , &c. These are indeed the only salts of cadmium ; the suboxide 
 when treated with acids, yields metallic cadmium and a protosalt. 
 
 Suboxide of Cadmium, Cd'O, is obtained by heating the oxalate to about the melt- 
 ing point of lead. It is a green powder, resembling oxide of chromium, and is resolved 
 by heat or by acids, into metallic cadmium and the protoxide. It does not however 
 yield metallic cadmium when treated with mercury : hence it appears to be a definite 
 compound, and not a mere mixture of the metal with the protoxide. 
 
 Protoxide of Cadmium, or Cadmic Oxide, Cd 2 0, or CdO. Cadmium, heated in 
 the air, takes fire and is converted into protoxide. The same compound is formed 
 when vapour of cadmium and aqueous vapour are passed together through a red-hot 
 tube ; but it is most easily prepared by igniting the hydrate, carbonate, or nitrate. 
 It varies in colour from brown-yellow to blackish, according to the mode of preparation. 
 By boiling cadmium for some time in a long-necked flask, the oxide may be obtained 
 in purple crystals. Its specific gravity is 6*9502. It is quite fixed in the fire, and 
 does not melt at the strongest white heat. It is easily reduced by charcoal before the 
 blowpipe, and emits vapours of metallic cadmium, which is immediately reoxidised, 
 and forms a red or brown deposit on the charcoal (p. 703). It is insoluble in water, 
 but unites with it, forming a hydrate. 
 
 Ht/drate of Cadmium, CclIIO, is precipitated by potash from dilute solutions of 
 cadmic salts ; it may be obtained in indistinctly crystalline warty groups, by the action 
 of aqueous ammonia on metallic cadmium in contact with iron or copper. It is white, 
 absorbs carbonic acid from the air, is insoluble in the fixed alkalis, dissolves readily in 
 caustic ammonia, but not in carbonate of ammonia. It dissolves easily in sulphuric, 
 nitric, hydrochloric, and acetic acid. 
 
 C ADMIUM, PHOSPHIDE OP. Grey, with faint metallic lustre ; very brittle ; 
 difficult to fuse. Burns in the air with a bright flame, producing cadmic phosphate. 
 Hydrochloric acid dissolves it, with evolution of phosphoretted hydrogen. 
 
 CADMIUM, SULPHIBE OP. Cd 2 S, or CdS. This compound occurs in the 
 form of Grrecnockite, and is prepared as a pigment known by the name oijaunc briUant. 
 It is formed with difficulty by fusing cadmium with sulphur, more readily by igniting 
 cadmic oxide with sulphur ; precipitated in yellow flakes when sxilphydric acid or an 
 alkaline sulphydrate is brought in contact with a cadmium-salt. The native sulphide 
 crystallises in double six-sided pyramids and other forms of the hexagonal system, 
 with cleavage parallel to the terminal and lateral edges of a six-sided prism. Specific 
 gravity 4'8 (Brooke), 4-908 (Breithaupt). Hardness equal to that of calcspar. 
 Of diamond lustre, semi-transparent, honey -yellow ; yields an orange-yellow or a brick- 
 red powder ; becomes carmine-red when heated. Decrepitates when heated somewhat 
 strongly (Brooke, Breithaupt). The artificial sulphide, in the precipitated state, 
 is an orange-yellow powder, which, when heated to redness, becomes first brownish 
 and then carmine-red. It melts at an incipient white heat, and solidfies on cool- 
 ing, in transparent, lemon-yellow, micaceous laminae. It is not volatile at any 
 temperature (Stromeyer). Specific gravity of the fused artificial sulphide, 4-605. 
 (Karsten.) 
 
 Ih dilute hydrochloric acid it dissolves with difficulty, even when the acid is heated ; 
 but if the acid be strong, the sulphide dissolves with ease, even at ordinary tempe- 
 ratures, with violent evolution of sulphuretted hydrogen, and without separation of 
 sulphur. At a red heat, it slightly decomposes vapour of water ; at a white heat, 
 oxide of cadmium is formed (Regnault). It dissolves in nitric acid, with evolution 
 of sulphuretted hydrogen and separation of sulphur. Very soluble in ammonia. 
 
 CADIvnuTA-ETHVIi. Cadmium appears to form with ethyl a compound ana- 
 logous to zinc-ethyl ; but it has not yet been obtained in the pure state. Wanklyn 
 (Chem. Soc. Qu. J. ix. 193), by heating cadmium-foil with half its weight of iodide of 
 ethyl dissolved in an equal volume of ether in a sealed tube, obtained a liquid whu-h 
 passed over in fractional distillation between 180 and 220 C., gave off first white and 
 then brown vapours on exposure to the air, and at length took fire, emitting a brown 
 smoke. It smelt like zinc-ethyl, and was decomposed by water, with effervescence 
 and formation of a white precipitate. It contained 36-8 per cent, cadmium, whereas 
 the formula C-H 5 Cd requires 66 per cent. Hence the distillate appears to have con- 
 tained about 56 per cent, of cadmium-ethyl, the remainder consisting of ether, iodide 
 of ethyl, and perhaps certain hydrocarbons. (See also Sonnenschein, J. pr. Chera. 
 Ixvii. 169.) 
 
CAESIUM CAFFEINE. 707 
 
 C.2ESIUIVE. Symbol Cs. Atomic weight = 124. An alkali-metal, the chloride of 
 which has lately been discovered by Bunsen and KirchhoiF, in the mother-liquors of 
 certain saline-waters in Germany. Its compounds give a spectrum distinguished by 
 two blue lines, one rather faint at about the middle of the blue space of the normal 
 spectrum, and the other much brighter, situated more towards the violet end. It was 
 by this peculiar spectrum that the metal was discovered (page 214).* 
 
 CAFFEIC ACID. See CAFFETANNIC ACID. 
 
 CAFFEINE or THEXUE. C 8 H 10 N 4 2 , or C*ff lo .tf'0 4 . (Gm. xiii. 223; Gerh. 
 i. 542.) Caffeine was discovered in coffee by Runge, in the year 1820 (Materialien 
 zur Phytologie, 1821, i. 146). Oudry (Mag. Pharm. xix. 49), in 1827, found in tea a 
 crystalline subtance, which he called theine, supposing it to be a distinct compound; 
 but Jobst (Ann. Ch. Pharm. xxv. 63) and Mulder (Pogg. Ann. xliii. 160), in 1838, 
 showed that it was identical with caffeine. Martius, in 1840 (Ann. Ch. Pharm. 
 xxxvi. 93), discovered the same substance in guarana, the dried pulp of Paulinia sor- 
 bilis;anA Stenhouse, in 1843 (Phil. Mag. [3] xxiii. 426), obtained it from Paraguay 
 tea, the leaves and twigs of Ilex Paroguayensis. The same chemist has shown (Phil. 
 Mag. [4] vii. 21) that it exists in the leaves as well as in the berries of the coffee- 
 plant. The exact composition of caffeine was first demonstrated in 1832 by Pfaff and 
 Liebig (Ann. Ch. Pharm. i. 17). Its combinations and reactions have been especially 
 studied by Stenhouse (he. tit. ; also Ann. Ch. Pharm. xlv. 366 ; xlvi. 227), Nichol- 
 son (Chem. Soc. Qu. J. iii. 321), Peligot (Ann. Ch. Phys. [3] xi. 128) and Eochleder 
 (Ann. Ch. Pharm. Ixxi. 1 ; Ixxiii. 56 and 123). Its alkaline nature was first demon- 
 strated by Herzog. (Ann. Ch. Pharm. xxvi. 344; xxix. 171.) 
 
 Preparation, a. From Tea or Coffee. 1. The mode of extraction generally adopted is 
 to treat tea or coffee with boiling water and mix the infusion with subacetate of lead to 
 precipitate the tannin. Peiigot adds subacetate of lead in excess, then ammonia. 
 The mixture is boiled for some time, the lead-precipitate carefully washed on a filter 
 with boiling water, the nitrate freed from excess of lead by sulphuretted hydrogen, and 
 after a second filtration, evaporated at a gentle heat. On cooling, it yields an abun- 
 dant crystallisation of nearly pure caffeine, and an additional quantity may be ob- 
 tained by concentrating the mother-liquor and leaving it to crystallise. 2. Caffeine 
 may also be obtained by saturating the free acid contained in infusion of tea or coffee 
 with carbonate of potassium ; treating the liquor with with infusion of gall-nuts ; mix- 
 ing the precipitate with dry hydrate of lime ; exhausting the mixture with alcohol ; ex- 
 pelling the alcohol from the filtrate by distillation ; and dissolving the residue in boil- 
 ing water or boiling ether (Robiquet and Boutron, J. Pharm. xxiii. 108). 3. Five 
 pts. of ground coffee are mixed with 2 pts. of slaked lime, and the mixture is ex- 
 hausted with alcohol in a displacement apparatus. The extract is then dried, pul- 
 verised, and again treated with alcohol; the alcohol separated from the extracts by 
 distillation ; the fat oil which floats on the surface is removed ; the watery liquid is eva- 
 porated to the crystallising point ; and the crystals of caffeine are pressed and deco- 
 lorised by animal charcoal : 50 kilogrammes of coffee thus treated yielded more than 
 250 grammes of caffeine (Versmann, Arch. Pharm. [2] Ixviii. 148). 4. Ground 
 coffee is digested for a week with commercial benzene, which takes up caffeine and oil 
 of coffee. Both remain behind when the benzene is distilled off, and maybe separated 
 by hot water, which dissolves the caffeine and leaves it in large crystals when evapo- 
 rated. The oil may also be dissolved out by ether, which leaves the caffeine undis- 
 solved (Vogel, Chem. Centralb. 1858, p. 367). 5. Payen exhausts coffee with ether, 
 then washes it thoroughly with alcohol of 60 per cent., concentrates the solutions to a 
 slightly syrupy consistence, and mixes them with three times their volume of 85 per 
 cent, alcohol, whereupon the liquid separates into two layers, the lower being viscid 
 and the upper fluid. The latter, which contains the greater part of the caffeine, is 
 decanted, and freed from the greater part of the alcohol by distillation ; and the syrupy 
 residue is mixed with one-fourth of its bulk of alcohol at 90 C., and left to itself in a 
 cool place : it then deposits crystals, which are recrystallised from alcohol. They con- 
 sist, according to Payen, of caffetannate (chlorogenate), of caffeine and potassium, and 
 when submitted to dry distillation, yield a sublimate of caffeine (Ann. Ch. Phys. [3] 
 xxvi. 108). 6. Caffeine or theine being volatile, may also be prepared by sublimation. 
 For this purpose, waste useless tea is gradually heated in a sublimation apparatus, like 
 that used for preparing benzoic acid, but not so strongly as to decompose the theine. 
 Part of the sublimate is quite pure ; the rest may be purified by recrystallisation from 
 water. (Heiynsius, J. pr. Chem. xlix. 317.) 
 
 According to the results of an extensive series of experiments made by Graham, 
 Stenhouse, and Campbell (Chem. Soc. Qu. J. ix. 33), coffee contains from 0'8 to 
 
 * See APPENDIX to this volume. 
 z z 2 
 
708 CAFFEINE. 
 
 1 per cent, of caffeine ; tea about 2 per cent. Stenhouse (Ann. Ch. Pharm. Ixxxix. 
 246) obtained from a sample of black tea from Kimaon on the Himalaya, 1'97 per cent, 
 theine, and from another sample of good black tea 2' 13 per cent. According to 
 Peligot (Ann. Ch. Phys. [3] xi. 68), Hyson tea contains from 2'2 to 3'4 per cent,, and 
 gunpowder tea from 2'2 to 4'1 per cent, of theine. According to Eobiquet and 
 Boutron (loc, cit.) Martinique coffee yields 0'36 per cent, Mocha coffee 0'206, and 
 Cayenne coffee 0'2 per cent, of caffeine. 
 
 b. From Guarana. Guarana mixed with ^ of its weight of quick lime is repeatedly 
 boiled with alcohol of 33 Beck; the filtrate is evaporated a little ; the greenish fatty 
 oil which separates on cooling is removed ; the residual alcoholic liquid completely eva- 
 porated ; and the dry residue is heated : caffeine then sublimes, at first yellowish- white, 
 afterwards quite white. 2. Twenty-four grammes of guarana powder are boiled with 
 a quart of water ; the cold solution is precipitated with basic acetate of lead ; the bulky 
 brownish-red precipitate filtered off, and repeatedly digested with hot water ; and the 
 lead is separated from the filtrate by sulphuretted hydrogen. The liquid separated 
 from the sulphide of lead is evaporated in the water-bath to dryness ; the residue dis- 
 solved in a little boiling alcohol, filtered, and allowed to crystallise; and the crystals 
 thus obtained are purified by pressing and recrystallisation. Guarana contains about 
 5 per cent, of caffeine. (Stenhouse.) 
 
 c. From Paraguay Tea. The filtered decoction is precipitated with neutral acetate of 
 lead and the filtrate with basic acetate (or it is boiled with litharge), and the liquid de- 
 canted from the precipitate is evaporated to dryness, a tough, dark brown, hygroscopic 
 mass then remaining. From this residue, caffeine may be obtained, either by subli- 
 mation, or by reducing it to powder, mixing it with sand, and treating it with ether. 
 After distilling off the ether, feebly coloured caffeine crystallises, and may be purified 
 by repeated crystallisation. The product amounts to 013 per cent, of the Paraguay 
 tea. (Stenhouse.) 
 
 [For a full account of the methods of preparing caffeine, see Gmelin's Handbook, 
 loc. cit.] 
 
 Properties Caffeine crystallises from water in slender needles, having the aspect 
 
 of white silk, and containing 8-4 per cent, water of crystallisation (C 8 H 10 N 4 2 + H 2 0), 
 which is not given off completely at 1 50 C. (Mulder). Specific gravity of the crystals 
 1-23 at 19 C. (Pfaff). It has a slightly bitter taste, and grates between the teeth. 
 Melts at 178, and sublimes completely at 185 in capillary and feathery needles 
 (Mulder). It is sparingly soluble in cold water and alcohol, still less in ether. 
 Boiling water dissolves it more freely, and the solution solidifies in a pulp on cooling. 
 The crystals which separate from ether and alcohol are anhydrous. 
 
 Decompositions. 1. Caffeine, when quickly and strongly heated, suffers partial de- 
 composition, giving off vapours which have the odour of methylamine. 2. Strong sul- 
 phuric acid decomposes it after continued heating. 3. When chlorine is passed into a 
 thick magma of caffeine and water, the crystals gradually disappear, and a mixture of 
 several substances is obtained, varying in composition according to the duration of the 
 action. With a comparatively small quantity of chlorine, the products are amalic 
 acid, C 6 H 6 N 2 4 , methylamine and chloride of cyanogen, together with chlorocaffeine, 
 C 8 H 9 C1N 4 2 . The formation of the three first-mentioned products is represented by 
 the equation : 
 
 C 8 H 10 N 4 2 + 2H 2 + Cl 4 = C 6 H 6 N 2 4 + CH 5 N + CNC1 + 3HC1. 
 
 The resulting liquid heated in the water-bath gives off hydrochloric acid, and a gas 
 smelling like chloride of cyanogen, and granular crystals of amalic acid separate, suc- 
 ceeded (if too much chlorine has not been passed through the liquid) by chlorocaffeine 
 in light flocks and crusts. If the action of the chlorine be prolonged, the compound 
 C 5 H 6 N 2 8 , called nitrotheine by Stenhouse, cholestrophane by Rochleder, and dimethyl- 
 parabanic acid [C 3 (CH 3 ) 2 N 2 3 ] by Gerhardt, is produced : 
 
 C 6 H 6 N*0 4 + Cl 2 + H 2 = C 5 H 6 N 2 3 + CO 2 + 2HC1. 
 
 Amalic acid. Nitrotheine. 
 
 4. Caffeine boiled with hydrochloric acid and chlorate of potassium yields alloxan or 
 a similar body, the aqueous solution of which colours the skin red and imparts to it 
 a peculiar odour. The solution gives with ammonia the colour of murexid, and with 
 alkalis and ferrous salts the colour of indigo. 5. Strong nitric acid boiled with 
 caffeine gives off nitrous fumes, and forms a yellow liquid, which assumes the purple 
 colour of murexid on adding a drop of ammonia (this reaction furnishes a test for 
 caffeine). If the ebullition be continued, the liquid becomes colourless, no longer ex- 
 hibits the purple colour with ammonia, and yields by evaporation crystals of dimethyl- 
 parabanic acid (nitrotheine), floating in a mother-liquor containing a salt of methyl- 
 amine. 6. Caffeine boiled with very strong potash-ley evolves a considerable quantity 
 of methylamine. 7. With soda-lime it gives off ammonia, forms carbonate of sodium, 
 
CAFFEONE CAFFETANNIC ACID. 709 
 
 carbonate of calcium, and a large quantity of cyanide of sodium. This reaction dis- 
 tinguishes caffeine from piperine, morphine, quinine, and cinchonine, which do not 
 form cyanide of sodium when similarly treated. (Eochleder.) 
 
 Compounds of Caffeine. Caffeine is a weak base : it dissolves in acids, forming 
 salts which have an acid reaction, and are for the most part decomposed by evapora- 
 tion, caffeine free from acid being deposited. 
 
 Hydrochlorate of Caffeine, C 8 H 10 N 4 2 .HC1, is obtained in crystals by dissolving 
 caffeine in very strong hydrochloric acid, not diluted either with water or with alcohol, 
 and concentrating by gentle evaporation. If either water or alcohol be added, nothing 
 but caffeine crystallises out. The salt forms large, transparent, efflorescent crystals, be- 
 longing to the trimetric system, ooP . P oo . oo P oo. Inclination of the faces, ooP : 
 oo P = 118 30' : P oo : c oo = 116 30'. 
 
 Chloroaurate of caffeine, C*H If N 4 O*.HCLAuCl t , crystallises from alcohol in orange- 
 coloured needles (Nicholson). The chloromercurate, C 8 H'N 1 2 .2HgCl, obtained by 
 mixing an alcoholic solution of caffeine with excess of mercuric chloride, forms needles 
 resembling caffeine, soluble in water, hydrochloric acid, alcohol, and oxalic acid, nearly 
 insoluble in ether. The cyanomercurate, C 8 H 10 N 4 2 .2HgCy, prepared in like manner 
 forms prisms belonging to the dimetric system, sparingly soluble in cold water and 
 alcohol. The chloroplatinate, C 8 H 10 N 4 2 .HCl.PtCl 2 , forms small distinct orange-yellow 
 crystals, sparingly soluble in water, alcohol, and ether. With chloride of palladium, 
 hydrochlorate of caffeine forms a beautiful brown precipitate, and the filtered liquid 
 deposits yellow scales of another compound, not unlike iodide of lead. 
 
 A solution of caffeine does not precipitate sulphate of copper, protochloride of tin, 
 acetate of lead, or mercurous sulphate. Boiled with sesquichloride of iron, it forms, on 
 cooling, a brown-red precipitate, perfectly soluble in water, and probably consisting of 
 a double salt similar to the preceding. With nitrate of silver, caffeine forms the com- 
 pound AgN0 3 .C 8 H 10 N 4 2 , which separates on mixing concentrated solutions of caffeine 
 and nitrate of silver, in white crystalline hemispheres, adhering firmly to the sides of 
 the vessel. It is sparingly soluble in cold, more readily in hot water and alcohol ; deto- 
 nates when heated. 
 
 Sulphate of Caffeine is difficult to crystallise, and is easily decomposed by water. 
 
 Tannate of Caffeine is obtained as a white precipitate when an aqueous solution of 
 caffeine is added in excess to aqueous tannic acid. It contains 41'9 per cent, caffeine 
 and 58-1 tannic acid (Mulder). An infusion of tea, by its tannin, also precipitates a 
 solution of caffeine. 
 
 C AFFEOKTE, The aromatic principle of coffee. It may be isolated by distilling 
 5 or 6 Ibs. of roasted coffee with water, agitating the aqueous distillate with ether, 
 and afterwards evaporating the ether. It is a brown oil, heavier than water, slightly 
 soluble in boiling water. An almost imponderable quantity of it is sufficient to aro- 
 matise more than a quart of water. (Pelouze et Fremy, Trait6, iv. 449.) 
 
 CAFFETANNIC ACID. Caffeic Acid. Chlorogenic Acid. C^H^O 17 ? (Pfaff, 
 1830, Scher. Ixi. 487. Eochleder, Ann. Ch. Pharm. lix. 300; Ixiii. 193; Ixvi. 35; 
 Ixxxii. 196. Liebich, ibid. Ixxi. 97. Stenhouse, ibid. Ixxxiii. 244. Payen, Ann, 
 Ch. Phys. [3] xxvi. 108. Gerh. Traite, iii. 886.) This acid exists in coffee berries 
 to the amount of 3 to 5 per cent, as a calcium- and magnesium-salt, and, according to 
 Payen, as a double salt of caffeine and potassium. According to Rochleder,it is also 
 found in Paraguay tea. It is prepared by mixing an alcoholic infusion of coffee op 
 Paraguay tea with water to separate the fatty matter; then boiling the liquid, adding 
 acetate of lead, decomposing the precipitate with sulphuretted hydrogen, and evapo- 
 rating the filtered liquid. It forms a yellowish brittle mass, which may with difficulty 
 be obtained in colourless, mammellated, crystalline groups. It dissolves easily in water, 
 less in alcohol; has an astringent taste, and reddens litmus strongly. Melts when 
 heated, then chars, and gives off the odour of roasted coffee. By dry distillation it 
 yields water and a thick oil, which solidifies on cooling, and consists of oxyphenic acid 
 (Kochleder). Strong sulphuric acid dissolves it with the aid of heat, forming a blood- 
 red liquid. Distilled with peroxide of manganese and sulphuric acid, it yields quinone 
 (Stenhouse). It dissolves with yellow colour in potash and in ammonia. The am- 
 moniacal solution in contact with the air quickly turns green, producing viridic acid, 
 C 14 H 14 8 (?) (Eochleder.) 
 
 Caffetannic acid colours ferric salts green. It does not precipitate ferrous salts, but, 
 on adding ammonia, a nearly black precipitate is obtained. It does not precipitate 
 tartar-emetic or gelatin, but precipitates quinine and cinchonine. It reduces nitrate of 
 silver in specular form if the liquid is heated. 
 
 The formula of caffetannic acid is not definitely fixed. Rochleder first supposed it 
 to be C 1(i H 18 8 , but afterwards gave the preference to C 14 H 16 7 . Gerhardt (Traite", 
 iii. 886) suggested C 35 H :<8 17 , according to which caffetannic acid would be a homologue 
 
 z z 3 
 
710 CAINCIC ACID - CAJEPUT. 
 
 of gallotannic acid, C 27 H 2? 17 , differing from it by 8CH 2 . Pfaff supposes it contains two 
 acids, caffeic and caffetannic ; but Kochleder found only one, viz. caffetannic acid, with 
 Itraces of citric acid. 
 
 The caffctannates are but little known. Tliepotassiiim-salt is amorphous, soluble 
 in water, insoluble in alcohol, and turns brown from oxidation on exposure to the air. 
 The barium- and calcium-salts are yellow, and quickly turn green on exposure to the 
 air. The lead-salt is a white precipitate of very variable composition. 
 
 The caffetannate of cafftine and potassium, prepared as already described (p. 706), 
 forms spheroidal groups of crystals, which become electric by friction. They are very 
 soluble in water, less soluble in aqueous alcohol, nearly insoluble in absolute alcohol. 
 The aqueous solution turns brown when exposed to the air. They are decomposed by 
 dry distillation, swelling up strongly and yielding a sublimate of caffeine. Gently 
 heated with potash, they assume a red or orange colour. Heated with strong sulphuric 
 acid, they yield a liquid of deep violet colour, with a bronze pellicle on the surface. 
 Nitric acid colours them orange-yellow. 
 
 CAINCIC ACID. C 16 H 26 7 (?) (Francois, Pelletier, and Caventou, 1830, 
 J. Pharm. xvi. 465. Liebig, Ann. Ch. Phys. [2] xlvii. 185. Eochleder and 
 Hlasiwetz, Ann. Ch. Pharm. Ixxvi. 238. Grerh. Traite, iii. 746.) Found in the root 
 of cai'nca (Chiococca anguifuga, Martius), a rubiaceous plant growing in Brazil, and 
 used as a remedy against the bites of serpents ; also in the root of Chiococca racemosa (L.\ 
 a plant much used in the Antilles for the cure of syphilis and rheumatism. 
 
 It is prepared : 1. By exhausting cai'nca root with alcohol, concentrating the alco- 
 holic extract, mixing it with water, and adding milk of lime to the filtered liquid till 
 it loses its bitterness. An insoluble basic caincate of calcium is thus produced, which 
 is decomposed by a hot alcoholic solution of oxalic acid. The filtered solution, when 
 evaporated, yields caincic acid in shining needles (Pelletier and Caventou). 
 2. From the root of Chiococca racemosa, by exhausting the bark of that root with 
 alcohol ; mixing the solution with neutral acetate of lead, which throws down caffe- 
 tannate of lead, together with some caincate and phosphate ; then treating the filtrate 
 with subacetate of lead, which forms a yellow precipitate containing the greater part 
 of the caincic acid, with only traces of caffetannic acid. This precipitate being decom- 
 posed by sulphuretted hydrogen, and the filtrate sufficiently concentrated, the caincic 
 acid is deposited in crystalline flakes, which may be purified by crystallisation from 
 boiling water containing a little alcohol. 
 
 Caincic acid is inodorous ; tasteless at first, afterwards very bitter ; sparingly soluble 
 in water and ether, very soluble in alcohol. Eeddens litmus perceptibly. The crystals 
 give off 9 per cent, water at 100 C. (Liebig). When heated it softens, chars, and 
 yields a crystalline sublimate which is not bitter. Dilute acids and strong alkalis 
 convert it into quinovatic acid. 
 
 The ca'incatcs are but little known ; they have a bitter taste. The neutral caincates 
 of ammonium, potassium, barium, and calcium are soluble in water, deliquescent, and 
 uncrystallisable. Lime-water, added to the solution of neutral caincate of calcium, 
 produces a copious precipitate of a basic salt, soluble in boiling alcohol, whence it 
 separates in white flakes, which are strongly alkaline. The normal lead-salt, 
 C 16 H 24 Pb 2 7 + H 2 0, is precipitated on mixing strong alcoholic solutions of caincic acid 
 and acetate of lead. There are also basic lead-salts. 
 
 CAIRNGORM STONE. Smoky quartz. See QUARTZ. 
 
 CAJEPUT, OH OF. This oil is prepared in India by distilling the leaves of 
 Melaleuca Leucodendron (Z.) with water. It was formerly employed to a great extent 
 in medicine, both internally and externally, but is now but little used, and is seldom 
 met with in a pure or unchanged state, except in the hands of wholesale druggists. 
 As introduced into Europe, it possesses a light green colour, resembling that of a dilute 
 solution of chloride of chromium, which is caused by a resinous colouring matter dis- 
 solved in it in very small quantity. 
 
 The colour of the crude oil is also partly due to copper, the presence of which may 
 be accounted for, either by the use of a copper head in the distilling apparatus of the 
 Hindoos, or by intentional adulteration, resorted to for preserving the green colour of 
 the oil, which otherwise changes gradually by oxidation to a reddish-brown, the oil 
 then becoming unsaleable for medicinal purposes. That the oil possesses a green colour 
 of its own is proved by the fact that the colour remains after the complete removal of 
 the copper by sulphuretted hydrogen. 
 
 Oil of cajeput consists mainly of the dihydrate of a hydrocarbon called cajputene, 
 isomeric with oil of turpentine. Its specific gravity is 0'926 at 10 C. On submitting 
 it to fractional distillation, dihydrate of cajputene, which constitutes about two-thirds 
 of the crude oil, passes over between 175 and 178 C. ; smaller fractions, perhaps pro- 
 ducts of decomposition, are obtained from 178 to 240 and from 240 to 250 ; and at 
 
CAJPUTENE. 711 
 
 250 only a small residue is left, consisting of carbonaceous matter mixed with me- 
 tallic copper. On treating this residue with ether, a green solution is obtained, which, 
 when evaporated, leaves a green resin, soluble in the portion which boils between 175 
 and 178, and capable of restoring the original colour. (M. Schmidl, Trans. Roy. 
 Soc. Ed. xxii. [6] 360 ; Chem. Soc. Qu. J. xiv. 63.) 
 
 CAJPITTEMTE. C 10 H 16 . (Schmidl, loc. cit.) This compound is obtained, to- 
 gether with two isomeric hydrocarbons, isocajputene and paracajputene, by 
 cohobating dihydrate of cajputene with phosphoric anhydride for half an hour, and then 
 distilling off the liquid, whereupon cajputene passes over at 160 165 C. ; isocajputene 
 at 176 178, and paracajputene at 310 316. 
 
 Cajputene is permanent in the air. It is not affected by iodine at ordinary tempe- 
 ratures, but at a higher temperature, hydrogen is evolved and a black liquid is formed. 
 Bromine acts quickly on it, producing a dark viscid oil. With gaseous hydrochloric 
 acid, it forms a beautiful violet liquid, but no crystalline compound, even at 10 C. 
 A mixture of ordinary nitric and sulphuric acids acts upon it with violence, forming a 
 yellow bitter resin. 
 
 Cajputene is insoluble in alcohol, but dissolves in ether and in oil of turpentine. 
 
 Isocajputene, C IO H 16 . Obtained: 1, as above. 2, by distilling the dihydrate of 
 cajputene with oil of vitriol. It is an oil boiling between 176 and 178 C. Its odour is 
 less agreeable than that of cajputene, and becomes more pungent and aromatic by expo- 
 sure to the air, the oil at the same time acquiring a yellow colour. Specific gravity =* 
 0-857 at 16 C. Vapour-density of (1) = 4-82 ; of (2) = 4-52. 
 
 Iodine, bromine, gaseous hydrochloric acid, and a mixture of nitric and sulphuric acids, 
 act upon isocajputene in the same manner as on cajputene. With oil of vitriol, and 
 with dilute sulphuric, hydrochloric, or nitric acid (neither of which acts upon cajputene), 
 it forms dark viscid liquids. 
 
 Isocajputene is insoluble in water and in alcohol, but mixes in all proportions with 
 ether and with oil vf turpentine. 
 
 Paracajputene, C 20 H 32 , obtained as above mentioned, by distilling dihydrate of 
 cajputene with anhydrous phosphoric acid, passes over between 310 and 316 C. It is 
 very viscous, has a lemon-yellow colour, and in certain directions exhibits deep-blue 
 fluorescence. Vapour-density, by experiment = 7'96 ; by calculation (2 vol.) = 9*43. 
 The difference between the experimental and calculated vapour-densities is probably 
 due to decomposition, taking place at the high temperature required for the deter- 
 mination. 
 
 Paracajputene oxidises rapidly in contact with the air, acquiring a red colour and 
 resinous consistence. A mixture of nitric and sulphuric acids does not act so violently 
 on it as on cajputene and isocajputene. With hydrochloric acid gas, it forms a dark 
 viscid liquid, which does not yield crystals, even at 10 C. It is insoluble in water, 
 alcohol, and oil of turpentine, soluble in ether. 
 
 BROMIDE OF CAJPUTENE, C lo H 16 Br 4 . Obtained by the action of bromine on oil of 
 cajeput. When dry bromine is dropped into the rectified oil, a very brisk action takes 
 place, and the sides of the vessel become covered with yellow needles, which however 
 soon disappear ; but if the addition of the bromine be continued till the reaction almost 
 ceases, a dark, thick, viscous oil is formed, which, after several weeks, deposits a 
 granular substance. By boiling the mixture with alcohol, the granular substance is 
 extracted ; a heavy oil is left behind ; and the alcoholic solution, on cooling, deposits 
 bromide of cajputene as a soft crystalline substance having a fatty lustre and much 
 resembling cholesterin. 
 
 Bromide of cajputene melts at 60 C. and solidifies again at 32. By dry distillation, 
 it yields a liquid which crystallises again in the cooler parts of the retort. It is not 
 altered by boiling with aqueous potash. It dissolves in ether and in boiling alcohol. 
 
 Rectified oil of cajeput shaken up with bromine- water, forms a red resin, from which 
 a solid substance separates in small white prisms, extremely deliquescent and rapidly 
 decomposing. 
 
 Another crystallised bromine-compound (probably a hydrobromate a\alogous to the 
 hydriodate) is formed in the same manner as that compound (p. 713). 
 
 CHLORIDE OF CAJPUTENE, C 10 H ;6 C1 2 , is produced by the action of nascent chlorine 
 on the dihydrate (rectified cajeput oil). When the portion of the oil distilling between 
 175 and 178C. is mixed with very dilute nitric acid, and hydrochloric acid gas is 
 passed into the liquid, a violent action takes place in a few minutes, chlorine and 
 nitrous gas being evolved ; and, if the passage of the gas be continued, chloride of 
 cajputene ultimately sinks _to the bottom, as a limpid brown oil, which may be freed 
 from adhering nitric and nitrous acid by distillation over strong potash-ley. It has a 
 fragrant odour, and may be kept without alteration for any length of time, but is de- 
 
 zz 4 
 
712 CAJPUTENE. 
 
 composed by distillation. Boiled with nitrate of silver, it detonates in a peculiar 
 manner, and forms chloride of silver. 
 
 HYDBATES OF CAJPUTENE. Hemi-hydratc, C <20 IP 4 = (C 10 H 16 ) 2 .H 2 (or perhaps 
 monohydrate of paracajputene, C 20 H S2 .H'-0.) Obtained by the action of oil of vitriol on 
 oil of cajeput. When the crude oil is raised to the boiling-point in a deep open vessel, 
 and oil of vitriol continuously dropped into it, violent ebullition takes place, accom- 
 panied, after a while, by a peculiar crackling sound. As soon as this is observed, the 
 flame must be lowered and the acid very cautiously added, till the liquid suddenly 
 assumes a dark colour, extending in an instant from the surface throughout the whole 
 depth. The vessel must then be immediately removed from the fire, otherwise further 
 decomposition will take place, attended with evolution of sulphurous anhydride. The 
 upper oily liquid is separated from the acid on which it floats, well washed, and distilled, 
 and the portion which passes over from the 170 to 175 is collected and rectified. 
 It is an oily liquid, whose vapour-density, as found by experiment, is 5' 19 to 5'27. 
 Now the formula, C 20 H 34 O, if supposed to represent 2 volumes of vapour, gives for the 
 
 calculated vapour-density the number 10'04 (= x 0*0693), which is 
 
 nearly double the experimental number. Consequently, the molecule C 20 H S4 repre- 
 sents 4 volumes of vapour, and probably splits up at high temperatures into C 20 !! 32 
 and H 2 0, each of which occupies 2 volumes. (See ATOMIC WEIGHTS, p. 469.) 
 
 Monohydrate. C 10 H 18 = C IO H 16 .H 2 0. This is the chief constituent of oil of 
 cajeput (p. 710), and passes over in the fractional distillation between 175 and 178 C. 
 After rectification, it is a colourless oil which boils constantly at 175, has a specific 
 gravity of 0'903 at 17 C., and vapour-density, by experiment = 5*43 ; by calculation 
 (2 vol.) = 5 - 338. It dissolves in all proportions in alcohol, ether, and oil of turpentine. 
 
 Exposed to the air for a considerable time, in the moist state, it changes to a reddish 
 liquid, which ultimately exhibits a rather strong acid reaction with litmus. Iodine 
 dissolves in the oil, and under certain circumstances forms crystalline compounds 
 (p. 712). Bromine acts quickly upon it, and under similar circumstances forms crys- 
 talline compounds (p. 711). Chlorine gas passed into the oil raises the temperature, 
 but does not appear to act upon it further ; but nascent chlorine (evolved by passing 
 hydrochloric acid gas into the oil mixed with dilute nitric acid) converts it into di- 
 chloride of cajputene, C 10 H 16 C1 2 . Phosphoric anhydride heated with the monohydrate 
 takes away the whole of its water, converting it into cajputene, isocajputene, and para- 
 cajputene (p. 711). Chloride of zinc likewise dehydrates it, but less completely. Strong 
 sulphuric acid acts but very slowly on the oil at low temperatures ; but if the tempera- 
 ture be allowed to rise, sulphurous anhydride is given off, and the oil blackens and ulti- 
 mately suffers complete decomposition. If the action be checked at a certain point, a 
 sulpho-acid is formed, which yields a soluble barium-salt. Oil of vitriol dropped into 
 the oil at the boiling heat, in the manner above described takes away half the water, 
 forming monohydrate of cajputene. Dilute sulphuric acid, on the contrary, causes the 
 monohydrate to take up 2 at. more water, converting it into C 10 H 16 .3H S 0. Fuming 
 sulphuric acid converts the monohydrate into a thick brown liquid, which boils above 
 360. Fuming nitric acid rapidly oxidises the oil, even at ordinary temperatures, 
 forming a large quantity of oxalic acid. Ordinary nitric acid produces the same effect 
 at the boiling heat, but at ordinary temperatures it acts very slowly, converting the 
 oil into a red liquid. Distilled over permanganate or add chromate of potassium in 
 presence of sulphuric acid, it forms a thick resinous liquid. It does not appear to be 
 altered by digestion with peroxide of lead. In contact with aqueous potash, or when 
 dropped into melting potash, it forms a soluble salt, the acid of which is precipitated 
 as a resin by hydrochloric or sulphuric acid. Heated with sodium, it forms a crystal- 
 line mass, soluble in water and alcohol, and consisting of soda and an organic substance, 
 which is separated by strong acids in the form of a fragrant resin. When the vapour 
 of the monohydrate is passed over red-hot soda-lime, a yellow oil distils over, having 
 a peculiar odour quite different from that of the monohydrate ; at the same time 
 the soda-lime becomes blackened by deposited charcoal, and when treated with acids, 
 gives off a large quantity of carbonic anhydride. The yellow oil thus formed yielded 
 by distillation, a fraction boiling between 180 and 185 C. which gave in two analyses, 
 7976 and 80-03 per cent. C, 12'20 and 12-07 H, agreeing nearly with the formula 
 C 26 H 24 ? , which requires 79*59 per cent. C, 12-24 H, and 7'97 0. 
 
 Trihydrate of Cajputene, C IO H 22 O S = C 10 H I6 .3H 2 0. Produced by the action 
 of dilute sulphuric acid on the monohydrate, or on crude oil of cajeput. Two pts. of 
 dilute sulphuric acid are added to 1 pt. of the crude oil ; and the mixture is w>ll 
 shaken for several days till the watery liquid acquires a yellowish colour, and then left 
 to itself for about ten days, wheivupon it deposits crystalline tufts of the trihydratc, 
 adhering to the sides of the vessel. Tliu crystals melt at 120 C. and solidify again at 
 
CAJPUTENE CALAMINE. 713 
 
 85. On submitting them to dry distillation, an oily liquid passes over and condenses 
 again in the colder parts of the apparatus, apparently as the unaltered trihydrate. The 
 crystals dissolve sparingly in cold, easily in boiling alcohol. 
 
 Crystals having the same composition were deposited from a secondary fraction of 
 crude cajeput-oil, which distilled at 210 230 C., and was left for a very long time 
 moist and exposed to the air. The crude oil mixed with nitric acid and alcohol, 
 changes, in the course of seven or eight months, into a black heavy liquid in which 
 crystals are suspended, perhaps consisting of the trihydrate. The same compound 
 appears likewise to be formed in beautiful long prisms, when the crystalline mass 
 produced by passing hydrochloric acid gas into rectified oil of cajeput is thrown into 
 water or alcohol. 
 
 HYDROCHXORATES OF CAJPUTENE. The monohydrochlorate, C 10 H 16 .HC1, is obtained 
 by distilling the dihydrochlorate, and collecting apart the fraction which boils at 160 C. 
 A product having the same composition is obtained by treating the dihydro- 
 chlorate for several days with aqueous or alcoholic potash ; but its odour is different 
 from that of4he product obtained by simple distillation of the hydrochlorate, and re- 
 sembles that of pelargonic ether. 
 
 The dihydrochlorate, C IO H 16 .2HC1, is obtained by passing hydrochloric acid gas 
 through rectified cajeput-oil, mixed with a third of its volume of alcohol. or strong 
 aqueous hydrochloric acid. It crystallises from alcohol in beautiful radiating tufts ; 
 melts at 55 C. and solidifies again at 30. It has no taste or smell. By dry -distil- 
 lation, it gives off. hydrochloric gas at 60, and splits into several fractions, one of 
 which is the monohydrochlorate. It is also deprived of half its chlorine by heating 
 with aqueous or alcoholic potash. It dissolves sparingly in cold, easily in boiling 
 alcohol or ether. 
 
 HYDRIODATE OF CAJPUTENE. a. Anhydrous. C 10 H 16 .HI. Obtained by adding a 
 solution of phosphorus in sulphide of carbon to a solution of iodine and oil of caje- 
 put in the same liquid. The liquid becomes hot, assumes a reddish colour, deposits 
 red oxide of phosphorus, and gives off vapours, probably containing phosphoretted 
 hydrogen, and after ten or twelve days deposits crystals of the hydriodate. The re- 
 action is perhaps : 
 
 6(C le H 16 .H 2 0) + 6PI == 6C 10 H 17 I + 2PH 3 + P 2 + P 2 5 . 
 
 The crystals are deposited in cells like those of beehives, and possess a black metallic 
 lustre. They are soluble in alcohol and ether, and are very stable, not being altered 
 even by boiling with potash. 
 
 b. Hydrated, C 20 H 36 I 2 = 2(C 10 H 16 .HI).H 2 0, or Hydriodate of Hemihydratcd Caj- 
 putene, C'^H^O^HI. If iodine be added by small quantities, and with constant 
 stirring, to cajeput-oil till the temperature rises from 10 to 40 C., and the vessel be 
 then immersed in cold water, a black crystalline compound soon separates from it, and 
 on filtering, pressing the black substance between paper, and then dissolving it in 
 alcohol or ether, a solution is obtained, from which the hydrated hydriodate crystallises 
 in prisms having a fine yellow-green colour and metallic lustre, and melting at 80 C. 
 to a compound which does not recrystallise on cooling. Potash dissolves the crystals, 
 abstracting part of the iodine in the cold, and the whole when heated. The crystals 
 are insoluble in water, and are not decomposed thereby; they dissolve readily in 
 alcohol and ether. 
 
 CA.IiA.ZTE. Syn. of TURQUOIS. 
 
 CALA.1VCITJE. Native Carbonate of Zinc. Zinc-spar. Smithsonite. Galmei. Zn 2 C0 3 . 
 This mineral, which is one of the most abundant ores of zinc, occurs crystallised in 
 rhombohedrons with cleavage parallel to the rhombohedral faces. Eatio of principal 
 to secondary axes = 0-8070 : 1. Inclination of terminal faces = 107 40'. Also reni- 
 foi*m, botryoi'dal, and stalactitic, and in crystalline incrustations ; likewise granular, 
 earthy, and friable. Specific gravity = 4*45 ; hardness = 5. It is translucent or 
 .subtransparent ; white when pure, but often tinged more or less with grey, green, 
 or brown, from admixture of the carbonates of iron and manganese. Streak white. 
 Lustre vitreous, inclining to pearly. Brittle, with uneven, imperfectly conchoiclal 
 fracture. 
 
 Pure calamine is found in Somersetshire and Derbyshire. A specimen from Somer- 
 setshire analysed by Smith son (Nicholson's Journal, vi. 76) gave 35'2 per cent. CO 2 , 
 and 64 -8 Zn 2 0, which is exactly the theoretical composition. Generally, however, a 
 portion of the zinc is isomorphously replaced by iron, manganese, calcium, magnesium, 
 lead, and copper. The following are examples: a. From Nertzchinsk in Siberia, 
 analysed by Kobell (J. pr. Chem. xxyiii. 480.) b, c, d. From Altenberg near Aix-la- 
 Chapelle (Monheim, Bammelsberg's Miner alchemic, s. 227.) c, f. From Herrenberg 
 
714 
 
 C AL AMINE CALCIUM. 
 
 near Nirm, Aachen (Monheim, ibid.) g. A cupriferous variety called Herrerite, from 
 Albarradon in Mexico. (G-enth, Sill. Am. J. ii. xx. ; J. pr. Chem. Ixvi. 475.) 
 Zn'CO 3 Fe 2 CO 3 Mn^CO 3 Ca2CO 3 Mg^CO 3 Pb2Co 3 Cu'CO 3 SiO 2 Zn'^SiO" R2Q 
 96-00 2-03 _ 1-12 _ = 99-15 
 
 4-02 1-90 0-14 2-49 = 101-11 
 
 60-35 
 55-89 
 8492 
 85-78 
 74'42 
 93-74 
 
 32-31 
 
 36-46 
 
 1-58 
 
 2-94 
 
 3-20 
 
 3'47 2'27 0-41 _ = 98-50 
 
 6-80 1'58 2'84 _ _ 1-85 = 99'57 
 
 7-62 098 4-44 0'09 trace = 101-15 
 
 14-98 1'68 3'88 0-20 0'56 = 98'92 
 
 1-50 1-48 0"29 3-42 = 100-43 
 
 SIIilCEOUS. Siliceous oxide of zinc. Hydrous silicate of zinc. 
 Zinc-glance. Kieselzinkerz. Kicselgalmei. Zn 4 Si0 4 + H 2 0. (Dana applies to this 
 mineral the name calamine, distinguishing the preceding as Smithsonite.) Occurs in 
 crystals of the trimetric system. Katio of brachydiagonal, macrodiagoual, and prin- 
 cipal axis = 0-6385 : 1 : 0'6169. The crystals are short prisms (fig. 1_14) resulting 
 from the predominance of the faces <x>$2 and coPco , and un- 
 Fig. 114. symmetrically terminated, viz. at one end by the faces P, 
 
 and at the other by 2Po> .Poo . OP . |Po> (y) and iP (a). 
 Inclination of faces, ooP2 : ooP2 = 103 53' ; |Poo : iPoo = 
 51 34'; Poo : Poo = 63 20'; 2P : 2Poo =101 56'. Cleavage 
 perfect parallel to o>P2 ; somewhat less, parallel to Poo (Kop p ' s 
 Krystallogra^thie, pp. 250, 264). The mineral likewise occurs in 
 stalactitic, mammillary, botryoi'dal, and fibrous forms; also mas- 
 sive and granular. Specific gravity 3'16 3 '9. Hardness = 
 4-5 5. It is white when pure, sometimes blue, more or less 
 coloured by oxide of iron. Transparent or translucent. Lustre 
 generally vitreous. Streak white. Brittle, with uneven fracture. 
 Like many other unsymmetrical minerals, it is pyroelectric. 
 
 Before the blowpipe it melts with difficulty at the edges ; it 
 is not altered by heating on charcoal, either alone or with car- 
 bonate of sodium ; but with carbonate of sodium and borax it 
 is completely reduced, with formation of a zinc-deposit. It is 
 easily decomposed by acids, with separation of gelatinous silica ; 
 it also dissolves in potash-ley. 
 
 Siliceous 
 
 from Tarnowitz in Upper Silesia, 
 Zn 2 O, and 7-75 H*0 = 101 
 requiring 25-1 SiO 2 , 67'4 Zn a O, and 7*5 H J O. Sometimes a small portion of the zinc is 
 partly replaced by iron or lead: in a specimen from Nertzschinsk in Siberia, Hermann 
 found 2-70 per cent, oxide of lead. 
 
 .Siliceous calamine usually occurs, associated with the native carbonate, in calcareous 
 rocks. Large crystals are found at Nertzchinsk. (Dana, ii. 314; Rammelsbefg's 
 MI in ralchemie, s. 549.) 
 
 CAXiAT&ZTZZ. A variety of tremolite (q. v.) having an asparagus-green colour. 
 CALCAREOUS SPAR. See CALCSPAR. C AI.CEDONY. See CHALCEDONY. 
 CAXiCHANTTTOX. Pliny's term for copperas. 
 
 CALCINATION. The fixed residues of such matters as have undergone com- 
 bustion are called cinders in common language, and calces, or oxides, by chemists ; 
 and the operation, when considered with regard to these residues, is termed calcina- 
 tion. In this general way it has likewise been applied to bodies not really combustible, 
 but only deprived of some of their principles by heat. Thus we hear of the calcination 
 of chalk, to convert it into lime, by driving off its carbonic acid and water : of gypsum 
 or plaster stone, of alum, of borax, and other saline bodies, by which they are deprived 
 of their water of crystallisation ; of bones, which lose their volatile parts by this treat- 
 ment ; and of various other bodies. (See COMBUSTION.) 
 
 CALCITE. Syn. with CALCSPAR (p. 721). 
 
 CAX.crura. Symbol, Ca. Atomic weight, 20. Lime, the oxide of calcium, has 
 been known from the earliest times, and was used by the ancients in the composition 
 of mortar. Black, in 1756, first pointed out the difference between burnt and unburnt 
 lime. The metal was first incompletely isolated by Davy in 1808, and has recently 
 been obtained in the pure state by Matthiessen. 
 
 Calcium is the most widely diffused of the alkaline-earthy metals. The carbonate 
 cxvurs in a great variety of forms, and, as limestone, constitutes entire mountain ranges. 
 The sulphate, fluoride, phosphate, and silicate are also abundant natural products. 
 Less frequent are the chloride, nitrate, arsenate, and tungstate. Calcium also exists 
 a.s carbonate and phosphate in the bones of animals ; the shells of molluscs are almost 
 
CALCIUM: BROMIDE CHLORIDE. 715 
 
 entirely composed of the carbonate. In the bodies of plants, calcium exists in combina- 
 tion with various organic acids. 
 
 Preparation of the Metal. Davy in 1808 obtained calcium in an impure state by 
 electrolysis, similarly to barium (p. 500), and by passing vapour of potassium over red- 
 hot lime (?) Matthiessen (Chem. Soc. Qu. J. viii. 28) prepares the pure metal as 
 follows : A mixture of 2 at. chloride of calcium and 1 at. chloride of strontium, with 
 a small quantity of chloride of ammonium (this mixture being more fusible than 
 chloride of calcium alone), is melted in a small porcelain crucible, in which a carbon 
 positive pole is placed, while a thin harpsichord wire wound round a thicker one, and 
 dipping only just below the surface of the melted salt, forms the negative pole. The 
 calcium is then reduced in beads, which hang on to the fine wire, and may be sepa- 
 rated by withdrawing the negative pole every two or three minutes, together with the 
 small crust which forms round it. A surer method, however, of obtaining the metal, 
 though in very small beads, is to place a pointed wire so as merely to touch the surface 
 pf the liquid ; the great heat evolved, owing to the resistance of the current, causes 
 the reduced metal to fuse and drop off from the point of the wire, and the bead is taken 
 out of the liquid with a small iron spatula. Or, thirdly, the disposition of the appa- 
 ratus may be the same as that for the reduction of strontium (q. v.) 
 
 Lies-Bodart and G-obin (Compt. rend, xlvii. 23) prepare calcium by igniting the 
 iodide with an equivalent quantity of sodium in an iron crucible, having its Hd screwed 
 down. According to Dumas (Compt. rend, xlvii. 175) it is essential that the process 
 be conducted in a closed vessel, as, under the ordinary atmospheric pressure, the sodium 
 burns away, and the iodide of calcium remains unaltered. 
 
 Properties. Calcium is a light yellow metal, of the colour of gold alloyed with 
 silver ; on a freshly cut surface the lustre somewhat diminishes the yellow colour, 
 which becomes more apparent when the light is reflected several times from two sur- 
 faces of calcium, or when the surface is slightly oxidised. It is about as hard as gold, 
 very ductile, and may be cut, filed, or hammered out into plates having the thickness 
 of the finest paper. Its specific gravity is 1'5778. In dry air the metal retains its 
 colour and lustre for a few days, but in damp air the whole mass is slowly oxidised. 
 Heated on platinum-foil over a spirit-lamp, it burns with a very bright flash. It is not 
 quickly acted on by dry chlorine at ordinary temperatures ; but when heated, it burns 
 in that gas with a most brilliant light ; also in iodine, bromine, oxygen, sulphur, &c. 
 With phosphorus, it combines without ignition, forming phosphide of calcium. Heated 
 mercury dissolves it as a white amalgam. Calcium rapidly decomposes water, and is 
 still more rapidly acted on by dilute nitric, hydrochloric, and sulphuric acids, nitric 
 acid often causing ignition. Strong nitric acid does not act upon it below the boiling 
 heat. In the voltaic circuit, with water as the liquid element, calcium is negative to 
 potassium and sodium, but positive to magnesium. It is not, however, reduced by 
 potassium or sodium from its chloride by electrolysis. On the contrary, a fused 
 mixture of CaCl with KC1 or NaCl, in certain proportions, yields potassium or sodium, 
 when subjected in a certain manner to electric action ; hence it appears that the metal 
 formerly obtained by reducing chloride of calcium with potassium or sodium, could not 
 be calcium, but was probably a mixture of potassium or sodium with aluminium, 
 silicon, &c. (Matthiessen.) 
 
 Calcium unites with all the non-metallic elements, forming compounds into which it 
 enters for the most part as a monatomic radicle, e. g. the chloride CaCl, the oxide Ca"O, 
 the sulphide Ca 2 S, &c. Most of the compounds are colourless ; they have an acrid 
 taste, and a lower specific gravity than the corresponding compounds of barium and 
 strontium. Of the compounds of calcium with other metals, little is known, excepting 
 that it forms an amalgam with mercury. 
 
 CAIiCIUIVT, BROMIDE OP. CaBr. Formed by the direct union of calcium 
 and bromine, or by dissolving lime or the carbonate in hydrobromic acid. The solu- 
 tion yields by evaporation colourless silky needles of the hydrated bromide, from 
 which the anhydrous bromide may be obtained by heating. It is deliquescent and 
 very soluble in alcohol. 
 
 CAIiClUlVT, CHXiORXDE OP. CaCl. This compound exists in sea- water, 
 river-water, and spring-water, and is produced by passing chlorine over red-hot lime, 
 or better by dissolving lime or the carbonate in hydrochloric acid, and evaporating. 
 It is also produced in large quantity in the preparation of ammonia by heating sal- 
 ammoniac with slaked lime : 
 
 NH'Cl + CaHO = CaCl + NH 3 + H 2 0. 
 
 The residue is treated with water ; the solution, which is always alkaline, is neutralised 
 with hydrochloric acid, and the residue evaporated to dry ness. 
 
 The aqueous solution, when highly concentrated, deposits the hydrated chloride, 
 
716 CALCIUM : DETECTION. 
 
 CaC1.3TFO, in six-sided prisms with pyramidal summits. It has a bitter taste. The 
 crystals give off 2 at. water when dried in vacuo, leaving the hydrate CaCl.H 2 O, which 
 retains the original form of the crystals, but is opaque, and has the appearance of talc 
 (Graham). At 200 G. they part with the whole of their water, leaving the anhy- 
 drous chloride in the form of a white porous mass. 
 
 The anhydrous chloride melts at a low red heat. If it be then exposed to the sun's 
 rays, it afterwards appears luminous in the dark ; it was formerly called Homberg's 
 phosphorus. When ignited in contact with the air, it is partially converted into oxide 
 and carbonate of calcium. Hence the porous chloride dried at about 200 C. is better 
 adapted for absorbing water in organic analysis (p. 228) than the fused chloride ; the 
 latter, containing lime, absorbs carbonic acid as well as water. 
 
 Anhydrous chloride of calcium is exceedingly greedy of water, and is one of the 
 most deliquescent substances known. 100 pts. of it in powder exposed to an atmo- 
 sphere saturated with moisture absorb 124 pts. of water in ninety-six days, more, there- 
 fore, than is required for complete deliquescence (Br a nd es, Schw. li. 433). The 
 crystallised chloride also deliquesces rapidly, and dissolves in half its weight of water 
 at C., in one-fourth of its weight at 16, and in every proportion of hot water. The 
 solution of the anhydrous chloride in water is attended with considerable evolution of 
 heat ; but the hydrated chloride in dissolving lowers the temperature of the liquid. 
 A mixture of crystallised chloride of calcium and snow produces a degree of cold suffi- 
 cient to freeze mercury. 
 
 Both the anhydrous and the hydrated chloride dissolve readily in alcohol. 10 pts. 
 of absolute alcohol at 80 C. dissolve 6 pts. of anhydrous chloride of calcium; and the 
 solution when evaporated in vacuo, at the winter temperature, yields rectangular 
 laminae containing 59 per cent, of alcohol, agreeing with the formula 4CaC1.7C 2 H 6 O. 
 The alcohol in this compound appears to take the place of water of crystallisation. It 
 likewise forms similar compounds with methylic and amylic alcohols. 
 
 Chloride of calcium combines with ammonia, forming the compound CaC1.4NH 3 , it 
 cannot, therefore, be used for drying gaseous ammonia. It unites also with chromic 
 acid and with acetate and oxalate of potassium. 
 
 A solution of chloride of calcium boiled with slaked lime dissolves that substance, 
 and the filtered solution deposits an oxychloride of calcium, 2CaC1.3Ca 2 + 15IFO, 
 which is decomposed by pure water and by alcohol. 
 
 CALCIUM, DETECTION AND ESTIMATION OF. 1. Reactions in 
 the dry way. The hydrated chloride and a few other calcium-compounds, when heated 
 in the blowpipe flame on platinum- wire, impart a red colour to the flame, similar to 
 that produced by strontium-salts, but less intense. The colour disappears as soon as 
 the salts are dehydrated, and is not produced at all if barium is likewise present. 
 Alcohol burned on soluble calcium-salts exhibits a red flame tinged with yellow. 
 
 The spectrum of a flame in which a volatile calcium-compound is ignited, according 
 to Bunsen and Kirchhoff's method (p. 214), is distinguished by a broad bright green 
 line situated at about the confines of the green and yellow of the normal solar spec- 
 trum, and an intensely bright orange line situated nearer to the red end of the spec- 
 trum than the orange band of strontium, and about midway between the lines C and 
 1) of the solar spectrum. This reaction is best seen with the chloride, bromide, and 
 iodide of calcium ; the sulphate does not produce it till it has become basic, the car- 
 bonate exhibits it most distinctly after the carbonic acid has been expelled. Com- 
 pounds of calcium with the non-volatile acids require to be decomposed, generally 
 by hydrochloric acid. To obtain the reaction with silicates not decomposible by hy- 
 drochloric acid, a small quantity of the mineral in fine powder is mixed on a platinum 
 plate with excess of fluoride of ammonium, and gently heated till all the fluoride is 
 volatilised ; the residue is then moistened with sulphuric acid, and the excess of that 
 acid driven off. If the remaining substance be ignited in the flame as above, the cha- 
 racteristic spectra of the alkali-metals, if present, are first seen, and afterwards those 
 of strontium and calcium. If only a trace of calcium is present, the bead must be 
 held for a few minutes in the reducing flame of the blowpipe, then moistened with 
 hydrochloric acid, and again ignited in the gas-flame. 
 
 2. Reactions in the wet way. The bromide, chloride, iodide, nitrate, acetate, and 
 many other organic salts of calcium are soluble in water; the carbonate, berate, phos- 
 phate, arsenate, and oxalate are insoluble, the sulphate sparingly soluble ; all of them, 
 however, except the sulphate, dissolve readily in nitric or hydrochloric acid. 
 
 In the aqueous solutions of calcium-salts, potash or soda produces a white gelatinous 
 precipitate of hydrate of calcium, unless the solution is very dilute. Ammonia : no 
 precipitate. Neutral carbonates of alkali-metals : white precipitate of carbonate of 
 calcium, soluble with effervescence, in nitric, hydrochloric and acetic acids. Acidcar- 
 /)<,<! tit of alkali-metals : no precipitate in the cold; pulverulent precipitate on boiling, 
 attended with escape of carbonic acid. Sulphuric acid and soluble sulphates : white 
 
CALCIUM: ESTIMATION. 717 
 
 precipitate of sulphate of calcium, unless the solution is very dilute ; in that case, the 
 precipitate appears on addition of alcohol, in which the sulphate of calcium is quite 
 insoluble. Oxalic acid and oxalate of ammonium : white precipitate of oxalate of 
 calcium, easily soluble in nitric or hydrochloric acid, but insoluble in acetic acid. 
 Sulphydric acid, alkaline sulphides, ferrocyanide of potassium, hydrofluosilicic acid : 
 no precipitate. 
 
 By these characters calcium in solution may be immediately distinguished from all 
 other metals, except barium and strontium, and from these it may be distinguished 
 by the greater solubility of its sulphate. A solution of sulphate of calcium gives a 
 white precipitate immediately with a soluble barium-salt, and after a while with a salt 
 of strontium. 
 
 3. Quantitative Estimation. Calcium maybe estimated either as carbonate 
 or as sulphate. The best method of precipitating it, is in most cases by oxalate of 
 ammonium, the oxalate being the least soluble of all the salts of calcium. If the solu- 
 tion contains an excess of any strong acid, such as nitric or hydrochloric acid, it must 
 be neutralised with ammonia before adding the oxalate of ammonium, because oxalate 
 of calcium is soluble in the stronger acids. The precipitate, after being washed with 
 hot water and dried, is heated over a lamp, care being taken not to allow the heat to 
 rise above low redness. It is thereby converted into carbonate of calcium containing 
 40' 15 per cent, of calcium or 56'12 of lime. 
 
 If, however, the solution contains any acid which forms with lime a compound in- 
 soluble in water, phosphoric or boracic acid for example, this method of precipitation 
 cannot be adopted ; because, on neutralising with ammonia, the lime would be preci- 
 pitated in combination with that acid, and would not be converted into oxalate on 
 addition of oxalate of ammonium. In such a case, the calcium may be precipitated as 
 sulphate by adding pure dilute sulphuric acid and alcohol. The sulphate, when dried, 
 contains 41*25 per cent, of lime. From acid solutions of phosphate of calcium the 
 metal may, however, be precipitated by oxalate of ammonium, with addition of acetate 
 of ammonium, because oxalate of calcium is insoluble in acetic acid, which dissolves 
 the phosphate with facility. 
 
 4. Separation from other Elements. From the metals of the first group 
 (p. 217) calcium is easily separated by sulphydric acid, from those of the second, by 
 sulphide of ammonium. 
 
 From the alkali-metals, calcium is easily separated either by oxalate of ammonium, 
 or by sulphuric acid and alcohol. 
 
 Calcium is separated from barium by precipitating both the earths as carbonates, 
 dissolving the carbonates in nitric acid, evaporating to dryness, and digesting the 
 residue in absolute alcohol, which dissolves nitrate of calcium, but not nitrate of 
 barium. They may also be separated in this manner in the form of chlorides, but the 
 separation is less complete, because chloride of barium is not quite insoluble in abso- 
 lute alcohol. 
 
 From strontium, calcium is separated in the same manner, nitrate of strontium being 
 likewise insoluble in absolute alcohol. 
 
 When baryta, strontia, and lime occur together, the baryta is first separated by 
 hydro-fluosilicic acid ; the strontia and lime in the filtrate are then converted into sul- 
 phates ; these sulphates, after being weighed, are converted into carbonates, either by 
 fusion with carbonate of sodium or by boiling with the aqueous solution of that salt ; 
 the carbonates weighed; and the quantities of strontium and calcium determined, us fol- 
 lows : Let x be the weight of the strontium, y that of the calcium, s that of the sul- 
 phates and c that of the carbonates ; then we have the equations : 
 
 Sr'SO* Ca 2 S0 4 Sr 2 C0 3 Ca 2 C0 3 
 
 -a?-"*- -a#- y = s; ~&r* + -c*-y = c - 
 
 183-8 136 157-8 100 
 
 r -9T8* + "40^ =S; ~9F8* + -40^ -* 
 
 Or, the carbonates may be dissolved in nitric acid, and the nitrates separated by abso- 
 lute alcohol, as above. 
 
 5. Atomic Weight of Calcium. Dumas found that 100 pts. of Iceland spar, 
 Ca 2 O.C0 2 , yielded by calcination 56 pts. lime, Ca*0, whence (since CO 2 = 44) the 
 atomic weight of lime =56, and that of calcium 20. Erdmann and Marchand, and like- 
 wise Berzelius, in repeating this mode of estimation, found for calcium the number 
 20'03. Berzelius (Traite, iv. 538) by converting pure lime into the sulphate, found 
 Ca = 20-13. Lastly, Dumas (Ann. Ch. Phann. cxiii. 33) has determined this number by 
 decomposing pure chloride of calcium with nitrate of silver. White marble was treated 
 with dilute hydrochloric acid ; the solution mixed with excess of lime (prepared from 
 the same marble)- the filtrate evaporated ; the residue again treated with hydrochloric 
 
718 CALCIUM: FLU OKIDE OXIDE. 
 
 acid, and ignited in hydrochloric acid gas ; and the pure chloride of calcium thus 
 obtained was decomposed by nitrate of silver. Three experiments thus made gave 
 respectively Ca = 20-00, 20-03, 20-00. The number 20 is generally adopted. 
 
 CAIiClurvi, PXiTTORXDX: OP. CaF. This compound occurs abundantly in 
 nature, sometimes massive, sometimes crystallised in octahedrons, cubes, and other 
 forms of the regular system (see FLUOR-SPAR). It is peculiarly a constituent of 
 metalliferous veins. In minute quantity it is very generally diffused, being associated, 
 to the amount of a few thousandths, with phosphate of calcium, in the bones of animals, 
 and in somewhat larger quantity in the enamel of the teeth ; minute quantities of it 
 also found in plant-ashes and in the earthy deposit formed in sea-water by boiling. 
 It may be prepared artificially as a gelatinous mass, by precipitating a soluble calcium- 
 salt with fluoride of potassium or sodium, or in the granular state, by neutralising 
 hydrofluoric acid with carbonate of calcium. 
 
 Fluoride of calcium dissolves in about 2000 pts. of water at 15 C. (Gr. Wilson), 
 and somewhat more abundantly in water containing carbonic acid ; hence its occurrence 
 in sea-water. It dissolves in free hydrofluoric acid and in strong hydrochloric acid, 
 and is precipitated as a transparent jelly by ammonia. It melts at a high temperature, 
 and crystallises on cooling. It is decomposed at a high temperature by vapour of water, 
 yielding lime and hydrofluoric acid. Fused with hydrate or carbonate of potas- 
 sium, or sodium, it yields oxide or carbonate of calcium and an alkaline fluoride. 
 Strong sulphuric acid does not decompose it at ordinary temperatures, but on heating 
 the mass, hydrofluoric acid is given off, and sulphate of calcium remains. Vapour of 
 sulphide of carbon passed over a red-hot mixture of fluor-spar and charcoal at a red 
 heat, decomposes the fluoride completely, forming sulphide of calcium and volatile 
 fluorine-compounds. It is also decomposed at a red heat' by chlorine. (Fr6my.) 
 (See FLUORINE.) 
 
 Fluor-spar is much used as a flux in metallurgic operations, especially in the treat- 
 ment of copper ores ; also in the reduction of aluminium (p. 151). 
 
 CAIiCXTTAX, IODIDE OP. Cal. Prepared by heating calcium in iodine vapour 
 or by dissolving lime or the carbonate in hydriodic acid, evaporating and fusing the 
 residue in a closed vessel. Resembles the chloride, melts below a red heat, and if in 
 contact with the air, is decomposed, with formation of lime and separation of iodine. 
 Very soluble and deliquescent. Decomposed by sodium at a red heat. The hydrate 
 crystallises in long needles. 
 
 CAXiCXTTlKC, OXIDE* OP. Lime,, Ca 2 0, or CaO. Anhydrous or quick lime is ob- 
 tained by heating to redness the carbonate, nitrate, or any salt of calcium con- 
 taining an acid easily expelled by heat ; but for actual preparation, the carbonate is 
 the only salt employed. In a closed vessel capable of resisting pressure, carbonate of 
 calcium may be melted without undergoing decomposition ; but when heated to redffess 
 under the ordinary atmospheric pressure, it gives off carbonic anhydride and leaves 
 lime (Ca 2 C0 3 = Ca 2 + CO). On the small scale, the decomposition may be per- 
 formed in a crucible heated in a furnace ; to obtain perfectly pure lime, the crystallised 
 carbonate or the finest Carrara marble should be used. On the large scale, masses of 
 limestone are burned in kilns, the mineral being mixed up with the coal or other com- 
 bustible matter. In general, one bushel of coal is sufficient to make five or six bushels 
 of lime ; magnesian limestones require less fuel than pure limestone. When a lime- 
 stone containing much aluminous or siliceous earth is to be burnt, great care should 
 be taken to prevent the fire from becoming too intense ; for such lime easily vitrifies. 
 The kilns for burning these argillaceous or siliceous limestones should be provided 
 with a damper. (See Ure's Dictionary of Arts, Manufactures, and Mines, ii. 729.) 
 
 Pure lime forms white hard porous masses of specific gravity 2*3 to 3*08. It bears 
 the strongest heat without decomposition, and melts only in the flame of the oxyhy- 
 drogen blowpipe or in the voltaic arc. Its most remarkable property is the avidity with 
 which it takes up water. When water is poured upon pure lime, it is instantly ab- 
 sorbed, and in a few seconds the lime becomes hot, gives off a large quantity of steam, 
 and crumbles to powder : this is called the slaking of lime ; with large masses the 
 evolution of heat and escape of vapour are very violent. Lime which slakes easily, is 
 called fat lime. Impure lime, especially that which contains clay, takes up water but 
 slowly : such lime is said to be poor. 
 
 The product of the action of water on lime, is hydrate of calcium or hydrate of lime, 
 CaHO or Ca 2 O.H 2 O. It is a white soft powder, which gives off its water at a red 
 heat, and is reconverted into quicklime. It is sparingly soluble in water, more in cold 
 than in hot water: hence, water saturated with lime in the cold, deposits the hydrate 
 when boiled. A solution evaporated in vacuo over oil of vitriol, deposits the hydrate 
 in hexagonal prisms (G-ay-Lussac). According to Dalton, lime-water formed at 60 
 130, and 212 (Fahr.) contains 1 grain of lime (anhydrous) in 778, 972, and 1270 grs. 
 
CALCIUM: OXYCHLORIDE PHOSPHIDE. 719 
 
 of water. The solution, called lime-water, is alkaline, and has a caustic taste. It pre- 
 cipitates most metallic oxides from their solutions, all those in fact which are insoluble 
 in water ; also carbonic, boracic, silicic, and phosphoric acids when added to their 
 neutral or alkaline solutions, or in excess to their acid solutions. When exposed to 
 the air, it soon becomes covered with a pellicle of carbonate of calcium. The solid 
 hydrate also absorbs carbonic acid from water, forming, according to Fuchs, the 
 hydrocarbonate Ca s C0 3 .HCaO. 
 
 Lime dissolves readily in nitric, hydrochloric, and acetic acid. The hydrate exposed 
 to the action of chlorine gas, forms a mixture of chloride and hypochlorite of calcium, 
 commonly called chloride of lime or bleaching powder: 
 
 Ca 2 + Cl 2 = CaCl + CaClO. 
 
 Chlorine does not act upon anhydrous lime or on the carbonate. 
 
 Lime is applied to a variety of useful purposes : 1. For making mortar. The 
 lime in the state of hydrate, is mixed with 2 pts. of coarse or 3 pts. of fine sand, and 
 made with water into a paste, which as it dries, absorbs carbonic acid slowly from the 
 air, and is converted into a hard mass of Tiydrate and carbonate, which binds the 
 stones or bricks firmly together. The chief use of the sand is to prevent by its mass 
 the too great contraction of the mortar in drying. 2. In tanning, to promote the 
 separation of the hair or wool from the skins, and of the fat and fleshy parts. 3. In the 
 preparation of caustic alkalis from their carbonates. 4. In the saponification 
 of fatty bodies intended for the preparation of stearine candles. 5. In the defe- 
 cation of sugar (see SUGAR). 6. As a manure. Soils containing too much clay, 
 are often mixed with lime, which, by absorbing water and carbonic acid, swells and 
 disintegrates, and thus renders the soil lighter. It also exerts a decomposing action 
 on the clay, rendering the silicate of potassium soluble. 
 
 Peroxide of Calcium, CaO, is known only as a hydrate, which falls down in very 
 fine crystalline scales when lime-water is mixed with an aqueous solution of peroxide 
 of hydrogen. (T h e n ar d.) 
 
 CAX.CXTTM, OXYCHX.ORIDE OF. (See page 716.) 
 
 CALCIUM, OXYGETJ-SALTS OF. See the several ACIDS. 
 
 CAI.CXUIVT, OXirsiTXiPHXDXj OF. When sulphide of calcium prepared by 
 reducing the sulphate with charcoal, is boiled with a large quantity of water, the 
 solution filtered hot, and evaporated in a retort containing air, a large quantity of 
 sulphuretted hydrogen escapes with the watery vapours : the cooled liquid deposits 
 sulphite of calcium, and on further concentrating the mother- liquor, gold-coloured 
 needles are obtained consisting of an oxysulphicle Ca I2 S 5 O + 20 aq. When heated out 
 of contact with the air, they give off water and sulphur, without alteration of form, and 
 leave a white residue, which, when treated with hydrochloric acid, deposits sulphur, 
 gives off sulphuretted hydrogen, and forms a product containing sulphate of calcium. 
 (H. Rose, Fogg. Ann. xv. 433.) 
 
 CALCIUM, PHOSPHIDE OF. CaP or Ca 2 P ? Prepared by passing vapour 
 of phosphorus over red-hot lime. A good mode of proceeding is to place a few pieces of 
 phosphorus at the closed end of a combustion-tube, fill the tube with small lumps of 
 quick lime (made by forming slaked lime into pellets and calcining them), then heat 
 the part of the tube containing the lime to redness, and pass the vapour of phosphorus 
 over it by cautiously surrounding the closed end of the tube with hot fuel. To pre- 
 pare larger quantities, a crucible having a hole at the bottom is filled with pellets of 
 lime, and placed on the grate of a furnace, and a flask containing phosphorus is placed 
 below the grating with its neck passing upwards through the hole in the crucible. The 
 fire is then lighted, and as soon as the crucible is red-hot, the phosphorus in the flask 
 is gradually heated, so that its vapour may pass upwards through the lime. The pro- 
 duct is a brown mass consisting, according to Th^nard, of hemiphosphide and pyro- 
 phosphate of calcium : 
 
 7Ca 2 + P 7 = 5Ca 8 P + Ca 4 F0 7 . 
 
 According to G-melin (Handb. iii. 188), it is a mixture of monophosphide and tribasic 
 phosphate of calcium : 
 
 4Ca 2 H- P 6 = 5CaP + Ca 8 P0 4 
 
 Possibly both these reactions may take place together. The product, when thrown 
 into water, is immediately decomposed, with evolution of spontaneously inflammable 
 phosphoretted hydrogen : 
 
 3CaP + 3H 2 = PH 3 + 3CaHO + P 2 ; or 3Ca 2 P + 3H 2 = 2PH 3 + 3Ca 2 + P. 
 
 Part of the diphosphide may also be decomposed in the manner represented by the 
 equation : 
 
 Ca'P + H 2 = PH 2 + Ca 2 0. 
 
720 CALCIUM: SELENIDE C ALCOFERRITE. 
 
 The formation of the compound PH 2 , may account for the spontaneous inflammability 
 of the gas. (See PHOSPHORETTED HYDROGEN, under PHOSPHORUS.) 
 
 CAIiCnriVf, SEXiEirXDES OP. A monosclcnide is formed by precipitating 
 chloride of calcium with monoselenide of potassium ; it is a flesh-coloured precipitate. 
 
 A polyselcnide, mixed however with selenite of calcium, is produced by heating 
 lime with selenium to a temperature .just below redness. Lime-water saturated with 
 seleniuretted hydrogen, deposits crystals of [mono ? ] selenide of calcium when exposed 
 to the air. 
 
 STTXiPHZDES OP. The monosulphide, Ca 2 S, is prepared : 1. By 
 decomposing the sulphate with charcoal or coal. 2. By decomposing the sulphate at a 
 red heat with carbonic oxide : Ca 2 S0 4 + 4CO = Ca 2 S + 4C0 2 . 3. By passing sul- 
 phuretted hydrogen over red-hot lime, water being formed at the same time. It is 
 white, amorphous, with hepatic taste and alkaline reaction. It is but sparingly 
 soluble in water : boiling water decomposes it, yielding sulphydrate and hydrate of 
 calcium : 
 
 Ca 2 S + H 2 = CaHS + CaHO. 
 
 Mixed with water, it is easily decomposed by carbonic acid, yielding carbonate of 
 calcium and sulphydric acid : 
 
 Ca 2 S i- H 2 + CO 2 = Ca 2 C0 3 + H 2 S. 
 
 The monosulphide, after being heated, shines in the dark; it was formerly called 
 Canton's Phosphorus. 
 
 Disulphide of Calcium, Ca 2 S 8 , is formed by boiling milk of lime with sulphur and 
 water, but not long enough to allow the lime to be completely saturated. The fil- 
 tered liquid on cooling, deposits crystals, whose composition agrees with the formula 
 Ca 2 S 2 .3H 2 0. (Herschell.) * 
 
 Pcntasidphide of Calcium, Ca 2 S 5 , is produced when the monosulphide or hydrate 
 of calcium is boiled for a considerable time with excess of sulphur. It absorbs oxygen 
 with avidity. "When hydrate of calcium is used, there is also formed an oxysulphide 
 represented by the formula Ca 12 S 5 0.20H 2 0, or 5Ca 2 S.Ca 2 0.20H 2 0. (H. K o s e. ) 
 
 SULPHYDRATE OF CAXCTUM, CaHS or Ca 2 S.H 2 S, is formed, together with the hydrate, 
 when the monosulphide is repeatedly boiled with water. The best mode of preparing 
 it is to pass sulphuretted hydrogen through hydrate or sulphide of calcium suspended 
 in a considerable quantity of water, as long as it is absorbed, stirring well all the 
 while. The solution thus formed has a sharp, bitter, hepatic taste, an alkaline reaction, 
 and slight causticity. The compound cannot be separated from it in the solid state, 
 even by evaporation in vacuo or in hydrogen gas, being resolved, as soon as crystalli- 
 sation begins, into sulphydric acid which escapes, and sulphide of calcium which 
 separates in silky prisms. If the solution be boiled down in a retort containing air, 
 sulphydric acid escapes and oxys\ilphide of calcium is deposited (p. 715). 
 
 Sulphydrate of calcium may be used as a depilatory, and is recommended for this 
 application byBottger (Ann. Ch. Pharm. xxix. 79), in place of sulphide of arsenic. It 
 may be prepared for the purpose by passing sulphuretted hydrogen into thin milk of 
 lime till the mass acquires a bluish-grey colour (from admixed sulphide of iron). The 
 paste thus formed, is laid, to the thickness of a line, on the surface from which the 
 hair is to be removed, and scraped off after a minute or two with a blunt knife, the 
 hair then coming away with it. If it could be produced cheaply enough, it might be 
 used for removing the hair from hides in the tan-yard. 
 
 C AI.C-SIWTER. Stalactitic carbonate of lime. It is found in pendulous conical 
 rods or tubes, mammelated, massive, and in many imitative shapes. Fracture lamellar, 
 or divergent fibrous. Lustre silky or pearly. Colours, white of various shades, yellow, 
 brown ; rarely green, passing into blue or red. Translucent, semi-hard, very brittle, 
 Large stalactites are found in the grotto of Antiparos, the Woodman's cave in the 
 Hurz, the cave of Auxelle in France, in the cave of Castleton in Derbyshire, and 
 Macalister cave in Skye. They are continually forming by the infiltration of carbonated 
 lime water, through the crevices of the roofs of caverns. Solid masses of stalactite have 
 been called oriental alabaster. The irregular masses on the bottoms of caves are called 
 stalagmites. U. 
 
 CAXiCOFESRRXTE. A yellow laminar mineral, from Battenberg in Rhenish 
 Bavaria, containing, according to Reissig, 34*01 per cent. P 2 5 ; 24*34 Fe 4 3 , 
 2-96 A1 4 3 , 14-81 Ca 2 0, 2-65 Mg'-O, and 20'56 water (= 99'27), a composition agreeing 
 nearly with the formula 2(2Ca 2 O.P 2 O 5 ).2Fe 4 3 .P 2 5 + 12aq. It exhibits perfect 
 cleavage in one direction, and traces in two other directions, oblique to each other but 
 perpendicular to the first, and is therefore probably orthorhombic. Specific gravity 
 2 -522-53. Hardness =2'5. Fuses readily before the blowpipe to a black, shining, 
 
CALCSPAR. 
 
 721 
 
 magnetic globule. Dissolves easily in hydrochloric acid. (Handw. d. Chem. ii. [2] 
 671.) 
 
 CAXiCSPAR. Calcareous Spar. Calcite, The rhombohedral form of carbonate 
 of calcium. The primary form is an obtuse rhombohedron (fig. 116), in which the 
 length of the principal axis to that of the secondary axis as 0-8543 to 1, and the 
 angle of the terminal edges is 105 5'. Of this, there are numerous modifications, 
 imong which are many acute and obtuse rhombohedrons, and likewise scalenohedrons, 
 but all distinctly cleavable parallel to the faces of the primary rhombohedron. The 
 primary form, + E, seldom occurs as an unbroken crystal in pure calcspar, but is the 
 prevailing form of bitter-spar (CaMgCO 3 ). Most of the forms occur only in combination. 
 The dimensions of the most frequently occurring rhombobedrons are given in the fol- 
 lowing table, each of them being the next acuter rhombohedron with relation to the 
 one above, and next obtuser with relation to that next below it (See CRYSTALLO- 
 GRAPHY, HEXAGONAL SYSTEM.) 
 
 Principal 
 axis. 
 
 0-2136 
 0-4271 
 0-8543 
 
 1-7086 
 3-4172 
 
 Inclination of faces 
 at terminal edges. 
 
 156 2' 
 134 57' 
 105 5' 
 
 78 51' 
 
 65 50' 
 
 Inclination of faces 
 at lateral edges. 
 
 23 58' 
 
 45 3' 
 
 74 55' 
 101 9' 
 114 10' 
 
 These forms, and combinations of them, are shown in figures 115, 116, 117, 118, 119, 
 120, 121. Fig. 115 is one of the most common of the rhombohedrons, and is fre- 
 
 Fig. 115. 
 
 Fig. 116. 
 
 Fig. 117. 
 
 Fig. 118. 
 
 Fig. 119. 
 
 \g. 120. 
 
 Fig. 121. 
 
 quently found alone, but still more frequently in combination with the hexagonal prism 
 producing the form seen in fi.g. 122. It occurs abundantly at Andreasberg in the Harz' 
 and in the mines of Derbyshire. Among the scalenohedrons, is the variety called 
 Dog s-tooth spar, + E 3 (fig. 123), in which the inclinations of the faces in the terminal 
 edges are 104 38' and 144 24'. It is found in Derbyshire and other localities It 
 frequently occurs also in hemitropic twin-crystals (fig. 124), which may be supposed 
 to be formed by cutting the crystal (fig. 123), in halves by a horizontal plane and 
 turning one of the halves through an angle of ISO . 
 
 The specific gravity of the purest crystals of calcspar is 2721. Hardness = 3, beinff 
 intermediate between gypsum and fluorspar. Calcspar when pure is colourless but 
 often exhibits various tints of yellow, green, red, brown, and even black, arising 'from 
 impurities. Lustre vitreous. Translucent more or less, and when transparent, exhibits 
 
 VOL. I. 3 A 
 
722 
 
 C ALCTUFF - C ALLUN A. 
 
 in a remarkable degree, the double refraction of light. This property is best seen in 
 the beautiful crystals obtained from Iceland, hence known as Iceland spar. These 
 crystals exhibit the ground-form R, being in fact merely fragments of larger crystals. 
 
 . 122. 
 
 Fig. 123. 
 
 Pig. 124. 
 
 Calcspar occurs in all parts of the world, and is one of the most abundant of 
 minerals. The lead-mines of Derbyshire and Cumberland, and of Andreasberg in the 
 Harz, are noted as affording the most beautiful crystals and the greatest variety of 
 form. [Respecting the circumstances under which carbonate of calcium assumes the 
 forms of calcspar and of arragonite, see ARRAGONITE, p. 358.] 
 
 C AIiCTUFF. An alluvial form of carbonate of calcium, probably deposited from 
 calcareous springs. It has a yellowish-grey colour, a dull lustre internally ; a fine- 
 grained earthy fracture ; is opaque, and usually marked with impressions of vegetable 
 matter. Its density is nearly the same as that of water. It is soft and easily cut or 
 broken. U. 
 
 C AIiCITIiUS or STONE. The name generally given to all hard concretions, not 
 bony, formed in the bodies of animals. (See BEZOARS, BILIARY CALCULI, UBINARY 
 CALCULI.) 
 
 CAXiDERlTE. A mineral from Nepal, said by Sochting (Deutsche geolog. 
 Gesellschaft, ix. 4) to be a kind of garnet. 
 
 CAIiEUOWITE. Cupreous Sulphocarbonate of Lead, from Leadhills in Scot- 
 and, consists, according to analyses by Brooke (Ed. Phil. J. iii. 117), and Thomson 
 (Phil. Mag. 1840, p. 402), of 3Pb 2 S0 4 .2Pb 2 C0 3 .Cu*C0 3 . It occurs in prismatic crystals 
 of the trimetric system, with numerous secondary faces, sometimes large, but usually 
 minute, and occasionally in branches diverging from a point. Specific gravity = 6'4. 
 Hardness = 2 - 5 3. Colour verdigris- or bluish-green. Streak greenish-white. 
 Lustre resinous. Translucent. Fracture uneven. Rather brittle. It is easily re- 
 duced before the blowpipe, and dissolves partially in nitric acid, with separation of 
 sulphate of lead. 
 
 CAXfENDT7IiXlir A mucilaginous substance extracted from the leaves and flowers 
 of the common marigold, Calendula ojficinalis. (Greiger, Diss. de Col. off., Heidelberg, 
 1848.) 
 
 CAX.ICO-PRIWTING. The art of dyeing cloth (chiefly cotton and linen), 
 topically ; that is, impressing figures in one or more colours on certain parts of the 
 cloth, while the rest of the surface is left in its original state. (See lire's Dictionary 
 of Arts, Manufactures, and Mines, i. 491.) 
 
 C AXiXFORNXir. A bitter principle extracted from Chica Calif ornica. ( W i n c k 1 e r, 
 Buchn. Repert. xxxii. 20.) 
 
 CAXiXSAYA BARK. See CINCHONA BARK. CAXiXiAXS. See TURQUOIS. 
 CAXiXiUXTA VTJXGARXS. An ericaceous plant, commonly called Ling. It 
 contains, according to Rochleder, a peculiar tannic acid ; the leaves and branches 
 
CALLUTANNIC ACID CAMPH AMIC ACID. 723 
 
 contain a trace of volatile oil, an acid, probably citric acid, and a small quantity of 
 ericolin. 100 pts. of the air-dried plant yield, according to Sprengel, T95 ash (i.) 
 Rothe found in the plant collected at the end of August, 5'55 per cent, water, and 
 the dried plant yielded 6'35 per cent, ash (n.) Nutzinger found in the air-dried 
 plant growing on moor-land, 2 - 87 per cent, ash (in.) ; and Thielau found in the flower- 
 ing plant growing on the lias sand-stone, 3'32 per cent, ash (iv.) The ash contained 
 in 100 pts : 
 
 K20 Na2Q Ca'O Mg2Q Al'O* Fe^CP Mn"Q3 Cl SO* P2Q* SiO* 
 
 I. . . 4-8 10-2 26-5 8-4 23 27 4-6 4'9 5'2 0'6 297 
 
 n. . .10-6 0-8 120 67 4-9 41 17 10'9 48-1 
 
 III. . . 6-4 5-4 33-5 8-0 08 2-0 3'8 1'8 1'4 4'0 327 
 
 IV. . . 296 15 5 6-6 0'5 1-5 4 7 4'1 I'D 5'3 30"9 
 
 C I4 H 14 9 or ^irC 9 (Rochleder, Ann. Ch. Pharm. 
 Ixxxiv. 354). The tannic acid of Calluna vulgaris. To obtain it, the alcoholic extract 
 of the green parts of the plant (without the root) is mixed with water ; the liquid filtered 
 from a green precipitate of fat, chlorophyll, &c., is precipitated with acetate of lead ; the 
 washed precipitate treated with very dilute acetic acid, in which it is but partially soluble ; 
 the filtrate mixed with excess of sub-acetate of lead ; the resulting yellow precipitate 
 decomposed by sulphuretted hydrogen ; and the filtered liquid evaporated on a chloride 
 of calcium bath, in an atmosphere of carbonic anhydride. Callutannic acid then remains 
 as an inodorous amber-coloured mass. This acid does not form any definite salts with 
 the alkali-metals, alkaline-earth-metals or silver : for its solutions in alkalis or alkaline 
 earths quickly absorb oxygen from the air, and oxide of silver is immediately reduced by it, 
 Rochleder has obtained two lead-salts to which he assigns the formnl'ddPbO.HO^C^H 6 ^ 
 and 8Pb0.2H0.3Cr A H 6 9 , and a stannic salt said to contain 7SnO' z .2H0.2C li H B O s . 
 
 Callutannic acid may be used to dye wool. The aqueous solution mixed with stannic 
 chloride and a few drops of hydrochloric acid, and heated to the boiling point, imparts 
 to wool mordanted with alum, a sulphur-yellow to chrome-yellow colour, according to 
 the strength of the solution and the time of immersion. 
 
 CAX.X.UXAN-THXN-. C 14 H 10 7 . A yellow flocculent substance obtained by 
 boiling callutannic acid with dilute mineral acids. It is sparingly soluble in cold 
 water, easily in hot water and in alcohol. It dissolves also in alkaline liquids, but 
 the solution quickly absorbs oxygen, and is then precipitated by dilute acids in red- 
 brown flocks. (Rochleder.) 
 
 CAXiOMEXi. Hemichloride of mercury or mercurous chloride. See MERCURY. 
 
 CAX.OPHYX.X.ITIVC RESIN. Maynas resin, C 14 H 18 4 . A resin from Maynas 
 in South America, obtained from Calophyllum Caloba or C. longifolium. It has the 
 aspect of common resin, dissolves in alcohol, ether, and oils, both fixed and volatile, 
 and crystallises from boiling alcohol in small transparent colourless prisms of specific 
 gravity 1-12. It melts at 105 C., but does not resolidify till cooled to 90. It is 
 decomposed by dry distillation ; dissolves with red-brown colour in sulphuric acid, 
 but is precipitated unaltered by water ; and when heated with nitric acid of specific 
 gravity 1*32, is said to yield butyric and oxalic acids, together with another acid which 
 does not precipitate calcium-salts. With chromic acid, it is said to yield carbonic 
 and formic acids. It dissolves in alkalis. (Levy, Compt. rend, xviii. 242.) 
 
 CALORIMETER. An instrument for the estimation of latent heat, specific 
 heat, heat of combustion, &c. (See HEAT.) 
 
 CAXiORXXkXOTOR. A voltaic arrangement consisting of one pair or a few pairs 
 of very large plates, used chiefly for producing considerable heat effects. (See ELEC- 
 TRICITY.) 
 
 CAXiSTROXTBARYTE. Shepard's name for a variety of heavy spar from 
 Shoharie in New York, mixed with carbonate of strontium and calcium. (Sill. Am. J. 
 xxxiv. 161.) 
 
 CAIiYPTOIiITE. A mineral from Haddam and Mittletown in Connecticut, 
 crystallised in square prisms of specific gravity 4 '34, hardness 6 - 5. Probably an 
 altered zircon. (Shepard, Sill. Am. J. [2] xii. 210.) 
 
 CAXVIBOXiEY RESIN". A resin from Morus indica. 
 
 CAMEXiXiXA JAPONXCA. The leaves contain tannin, which is sparingly 
 precipitated by gelatin, abundantly by lead and iron salts : they do not contain theine. 
 (S tenhouse.) 
 
 CAXKPEACHY WOOD. See LOGWOOD. 
 
 CAIKPHAMXC ACXD and CAMPHATCXDE. See CAMPHORAMIC ACID and 
 CAMPHORAMIDE. 
 
 3 A 2 
 
724 C AMPHENE C AMPH ENE S. 
 
 CHJVIPHZI3TE. This term is used in various ways; sometimes as a generic name 
 for the hydrocarbons isomeric or polymeric with oil of turpentine, sometimes as the 
 name of the radicle of camphor (C 10 H 16 ) and its allied compounds. By Dumas and 
 Berthelot, it has been applied especially to the hydrocarbon, also containing C H 16 , 
 obtained by the action of alkalis on hydrochlorate of turpentine-oil. Laurent applied 
 the same appellation to the radicle of oil of cloves, eugenin, &c. 
 
 Chlorinated and brominated derivatives of camphene, e. g. C 10 H 14 C1 2 and C 10 H I2 Br 4 
 are obtained by the action of chlorine or bromine on oil turpentine and its isomers. 
 A monochlorocamphene, C 10 H I5 C1, and a dichloride of camphene, C IO H ia Cl 8 , are produced 
 by the action of pentachloride of phosphorus on camphor (see p. 728). 
 
 CAIVIPHENES or Terebenes. The generic name for the volatile oils or hydro- 
 carbons C 5n H 8n , isomeric or polymeric with oil of turpentine. Most of them are isomeric 
 and consist of C 10 H 18 , e. g. oil of turpentine, oil of lemons, oil of juniper, caoutchin, 
 &c. ; some, as colophene, appear to consist of C 20 H 32 . 
 
 Many camphenes exist ready formed in plants, as the oils of juniper, lemon, and 
 turpentine ; they are often contained in the natural oils associated with oxygenated 
 compounds, and may be separated therefrom by fractional distillation, as carvene from 
 oil of caraway, borneene or valerene from oil of valerian, &c. Many are produced 
 from oxygenated compounds containing C 5n H 8n + water, by the action of phosphoric 
 anhydride (e. g. borneene from borneol, cinaebene from wonnseed-oil, &c.) Others are 
 formed from oxygenated oils by the action of hydrate of potassium (oil of sage and 
 others) ; some by dry distillation, as oil of amber, caoutchin, &c. 
 
 All the camphenes are liquid at ordinary temperatures (except Berthelot' s camphene, 
 which is a solid melting at 46 C.) ; they have for the most part a density of 0*8 to 
 0'9 (oil of parsley is the only one heavier than water, specific gravity = 1*0 to I'l), 
 and boil between 155 and 165 C. ; their observed vapour-density varies from 4-6 to 
 4'8, the formula C'H 16 calculated for 2 vol. giving a thoretical density of 47. A few 
 only boil at higher points, viz. oil of copaiba at 250 C. ; petrolene at 280 ; colo- 
 phene at about 310; cinsephene at nearly 320, metaterebene about 360. The 
 observed vapour density of carvene is 5*1, of tolene 57, of petrolene 9'4, of colophene 
 11-1 ; the formula C 20 H 32 calculated for 2 vol. requires 9-4. 
 
 Camphenes are distinguished one from the other by their odours, which in some, as 
 oil of lemon, are very fragrant, in others, as in oil of copaiba, extremely disagreeable ; 
 also by their action on polarised light. All natural camphenes possess the optical 
 rotatory power in a greater or less degree, some turning the plane of polarisation to the 
 right, others to the left ; but even in the same oil, the strength and direction of the 
 rotatory power vary according to the temperature and other circumstances. 
 
 Camphenes readily absorb oxygen and convert it into ozone. Iodine for the most 
 part decomposes them readily and with evolution of heat, sometimes even with slight 
 explosion, the iodine taking the place of a portion of the hydrogen ; this reaction 
 serves to detect the admixture of camphenes, oil of turpentine, for example, with other 
 volatile oils. Chlorine and bromine act in a similar manner. 
 
 Camphenes treated with bromine and water are easily converted into brominated 
 oils (Gr. Williams, Phil. Mag. [4] v. 536). According to Chautard (Compt. rend, 
 xxxiii. 671 ; xxxiv. 485), camphenes distilled with water and bromide or chloride of 
 lime, yield, amongst other products, bromoform or chloroform. 
 
 Most camphenes unite with hydrochloric acid, forming either liquid or crystallised 
 compounds, frequently having 'the composition C IO H 16 .HC1 or C 10 H 16 .2HC1; these 
 compounds, called artificial camphors, have the same rotatory power as the oils from 
 which they are produced. Similar compounds are formed with hydrobromic and 
 hydriodic acid. 
 
 Natural camphenes treated with acids, especially with strong sulphuric acid, gene- 
 rally undergo an alteration of molecular arrangement without change of chemical con- 
 stitution, the odour being for the most part greatly altered, sometimes also the 
 density and boiling point ; but the most characteristic alteration is the loss of optical 
 rotatory power. A camphene often yields several isomeric modifications by treatment 
 with different acids, or by repeated treatment with the same acid. The new camphenes 
 thus produced are called camphenes of the second order, or sometimes cam- 
 pherenes. Another class, called camphenes of the third order, or sometimes 
 camphilenes, are obtained by the action of lime or baryta at high temperatures 
 on the hydrochlorates of other camphenes; these are also optically inactive; and 
 generally differ greatly in odour from the original camphenes, but often exhibit nearly 
 the same specific gravity and boiling point. The camphenes of the second and third 
 orders are decomposed by chlorine, bromine, and iodine, and form liquid or crystallised 
 compounds with hydrochloric, hydrobromic, and hydriodic acids. 
 
 The camphenes are a very numerous class of bodies ; the principal of them are : 
 
CAMPHERENES CAMPHINE. 725 
 
 Oil of bergamot Gaultherilene Oil of pepper 
 
 Borneene Oil of gomart Petrolene 
 
 Carvene Oil of hops Oil of savin 
 
 Caoutchin Oil of juniper Thymene 
 
 Cinsebene Oil of lemon Tolene 
 
 Neutral oil of cloves Oil of orange Oil of turpentine 
 
 Oil of copaiba Oil of parsley 
 Oil of elemi 
 
 For details relating to specific gravity, boiling point, vapour-density, and rotatory 
 power, see the several oils. (Handw. d. Chem. ii. [2] 691 ; Gm. xiv. 271322 and 
 356404.) 
 
 CAIVIPHEREUES. Camphenes of the second order (p. 724). 
 
 CA1WPHERY1 or CAIVlPHEZiXIiE. A name applied by Laurent to the im- 
 pure camp ho rone (q.v.) which he obtained from camphorate of calcium. 
 
 CA1VIPHIC ACID. C 10 H 16 2 ? A product obtained, together with borneol, by 
 heating camphor with alcoholic soda-solution in sealed tubes to 170 190 C. 
 
 2C 18 H 1B + H 2 = C'H 18 + C 10 H 16 2 . 
 
 Camphor. Berneol. C.imphic acid. 
 
 On neutralising the product with sulphuric acid, dissolving out the camphate of sodium 
 with alcohol, evaporating and again adding sulphuric acid, the camphic acid separates 
 as a nearly solid, coloured mass, heavier than water, sparingly soluble therein, easily 
 soluble in alcohol. It is decomposed by nitric acid. The potassium and sodium-salts 
 are nearly insoluble in strong alkaline leys ; they precipitate the salts of copper, iron, 
 lead, silver, and zinc, not those of the alkaline-earth metals ; all the precipitates are 
 soluble in a large quantity of water. (Berthelot, Ann. Ch. Phys. [3] Ivi. 94.) 
 
 CAXttPHXDES. This term was applied by Laurent to nuclei in which the com- 
 bustible hydrogen is replaced by oxygen. 
 
 CAlVTPHIIiEM'E. Deville's name for the camphene obtained by treating hydro- 
 chlorate of turpentine-oil with lime. Camphenes of the third order (p. 724) are some- 
 times called camphilenes. 
 
 CAIVIPHIIWIDE. See CAMPHOKIMIDE. 
 
 cAtaPHXCT. C 10 H 18 or C 9 H 16 ? (Glaus, J. pr. Chem. xxv. 262 ; Gm. xiv. 448.) 
 Formed, together with campho-creosote, colophene, and campho-resin, by triturating 
 camphor with an equal weight of iodine, and distilling. A black mass then remains 
 containing campho-resin, and the distillate separates on standing, into a watery layer 
 containing hydriodic acid, and an upper oily layer containing camphin, campho-creo- 
 sote, and colophene. To obtain the camphin, the mixture is agitated with mercury, 
 to remove iodine, then rectified per se, and the most volatile portion shaken up with 
 potash-ley, and repeatedly rectified over potash-lime to remove iodine ; it may also be 
 freed from the last traces of iodine by setting it aside with potassium and rectifying. 
 
 Camphin is a thin colourless oil of specific gravity 0'827 at 25 C., and boiling at 
 167 170 undera pressureof 28 inches. It has a pleasant odour, like that of oil of mace, 
 somewhat also like turpentine. It gave by analysis 86-06 per cent. C and 1279 II ; 
 the formula C 10 H i8 requires 86-96 C and 13'04 H, while C 9 H 16 requires 87'10 C and 
 12-90 H. Gerhardt regarded it as impure cymene, C 10 H 14 (89-5 C and 10-5 H). 
 
 Camphin burns with a bright but/ very smoky flame. It dissolves in alcohol, ether, 
 oil of turpentine, and rock-oil; but not in water, weak alcohol, potash, or dilute acids, 
 or even in strong hydrochloric acid. It absorbs a small quantity of hydrochloric acid 
 gas. It is but slightly attacked by sulphuric acid. Nitric acid, with aid of heat, 
 converts it into a yellow nitrogenised oil, smelling like cinnamon, or by prolonged 
 heating, into a red oil soluble in potash. Pentachloride of antimony converts it into 
 a resin. 
 
 Camphin is readily decomposed by chlorine and bromine, yielding substitution-pro- 
 mts. The chlorocamphins are transparent, colourless, oily bodies, which, when 
 treated with alcoholic potash, yield chloride of potassium and a chlorinated oil having 
 an agreeable odour. Glaus obtained two compounds, which he regarded as C 9 H 13 C1 3 
 and C 9 H'C1 6 . 
 
 CAMPHXNS. This term is applied in commerce to purified oil of turpentine, 
 obtained by carefully distilling the oil over quick lime, sometimes also rectifying it 
 over dry chloride of lime ; in this manner it is obtained quite free from rosin. In 
 some cases, the oil is treated with sulphuric acid previous to rectification. This puri- 
 fied turpentine-oil is much used for burning in lamps, giving a very brilliant light. 
 It is however very apt to smoke, and must therefore be burnt in lamps of peculiar 
 construction, with very strong draught. A solution of camphine in three times its 
 
 3 A 3 
 
726 CAMPIIOCREOSOTE CAMPHOLIC ACID. 
 
 volume of alcohol of specific gravity 0-820, sometimes with addition of a little ether to 
 ensure more complete solution, is also used as an illuminating material, and may be 
 burned in ordinary lamps with argand burners. 
 
 C A MPHO CREOSOTE. A product of the decomposition of camphor by iodine 
 at high temperatures; according to Schweizer, it is probably identical with carva- 
 crol (q. v.) 
 
 CA.TVTPHOG-EKT. Dumas' name for the hydrocarbon C 10 H 14 , obtained from cam- 
 phor by the action of phosphoric anhydride ; it is identical with cymene (q. v.) 
 
 CAMPHOXi. This name was applied by Gerhardt to the camphor of the Lauracese ; 
 but Berth elot has recently applied it (Ann. Ch. Phys. [3] Ivi. 78), to Borneol or 
 Borneo-camphor, which he regards as the alcohol of a series in which common camphor 
 is the aldehyde, thus : 
 
 Ethyl-series. Carnphyl-series. 
 
 Ethyl-alcohol, C 2 H 6 Camphol, C 10 H 18 O 
 
 Aldehyde, C 8 H 4 Camphor, C IU H W 
 
 Acetic acid, C 2 H 4 2 Camphic acid, C'H 16 2 
 
 Chloride of ethyl, C 2 H 5 C1 Chloride of camphyl, C">H' 7 C1 
 
 Ethylene, C*H 4 Camphene, C 10 H 16 
 
 Camphol is produced by treating camphor with alcoholic potash (p. 626), just as ben- 
 zylic alcohol is produced from benzoic aldehyde (p. 578). It is also formed by distilling 
 amber with | of its weight of potash and a large quantity of water. 
 
 From later experiments by Berthelot and Buignet (Compt. rend. 1. 606), it 
 appears that the several bodies to which the name camphol has been applied, are iso- 
 meric but not identical, being especially distinguished by their different rotatory power, 
 which in camphol from common camphor = ->- 44-9 ; in natural camphor or borneol, 
 = + 33 '4; in camphol from amber = + 4 - 5; while in Isevo-rotatory borneol, or 
 camphol obtained from madder-camphor (p. 626), it is 33*4. 
 
 According to Berthelot, camphol heated with acids unites with them, like all 
 alcohols, with elimination of water. The resulting compound ethers may be purified 
 by removing the excess of acid with slaked lime and ether, and distilling off the excess 
 of camphol by prolonged heating at 150 J C. They are colourless, neutral, soluble in 
 alcohol and ether; some are liquids, others crystalline; the latter melt at a lower 
 temperature than camphol. Alkalis decompose them into acid and camphol, the latter 
 exhibiting its original properties. Benzoate of camphol, C I7 H 22 2 = C 7 H 5 (C 10 H 17 )O 2 , 
 is a neutral, colourless, inodorous oil. Stearate of camphot,CE. 5 -0' z = C 18 H 35 (C 10 H 17 )0-, 
 is colourless, inodorous, viscid, solidifying after a while in a crystalline mass. Chloride 
 vf camphyl, C 10 H' 7 C1, obtained by heating camphol (borneol) with strong hydrochloric 
 acid to 100 C. in a sealed tube for 8 or 10 hours, and purified by washing with 
 dilute potash and crystallisation from alcohol, has the aspect, odour, and empirical 
 composition of hydrochlorate of turpentine-oil or artificial camphor (C^H^.HCl), 
 but turns the plane of polarisation to the left, somewhat less strongly than borneol. 
 Heated to 180 C. with alcoholic soda-solution, it yields chloride of sodium and borneol. 
 By this and by its rotatory power, it is sufficiently distinguished from hydrochlorate of 
 turpentine-oil. (Handw. d. Chem. 2 te Aufl. ii. [2] 695.) 
 
 CAIVXPHOXiElsrE. C 9 H 16 . A liquid hydrocarbon obtained by distilling campholic 
 acid with phosphoric anhydride. Vapour-density 4*353. (Delalande.) 
 
 CAXKPHOXiXC ACID. Bornenic acid. C IO H 18 2 = C 10 H 17 O.H.O. Produced by 
 the action of hydrate of potassium on camphor. The quantity found under the ordi- 
 nary atmospheric pressure is but small : but if the camphor be enclosed, together with 
 potash-lime, in a sealed combustion tube of the ordinary dimensions, and its vapour 
 made to pass several times over the heated potash-lime, about 5 or 6 grammes of 
 purified acid may be obtained from each tube. To isolate the acid, the contents of 
 the tube are digested in water, and the solution decomposed by a stronger acid. The 
 campholic acid is then deposited as a crystalline mass, which may be purified by dis- 
 tillation. It is white, and crystallises well from a mixture of alcohol and ether ; melts 
 at 50 C. ; boils without alteration towards 250. Insoluble in water, but imparts to 
 it an aromatic odour. Vapour-density 6'058. Distilled with phosphoric anhydride, 
 it yields campholene, carbonic oxide being probably evolved at the same time : 
 
 CO + H 2 + C 9 H 16 . 
 
 It is monobasic. The calcium-salt, C 10 H 17 Ca0 2 , is a snow-white crystalline powder 
 obtained by pouring chloride of calcium into a nearly boiling solution of the acid in 
 excess of ammonia. By dry distillation, it yields an oily body called campholone, 
 C 19 H 33 : 
 
 2C 10 H 1 Ta0 2 = Ca'CO 3 f r"H 3 '0. 
 
CAMPHONE CAMPHOR. 727 
 
 Campholate of silver, obtained by decomposing the neutral ammonium-salt with nitrate 
 of silver, forms curdy flakes. (Delalande, Ann. Ch. Phys. [3] i. 120.) 
 CAIVTPHOWE. Syn. of CYMENE. 
 
 CAXVIPHOMETHYUC ACID. Camph orate of methyl and hydrogen. (See 
 CAMPHOKIC Aero, p. 733.) 
 
 CAMPHOR. C IO H 16 0. (Gm. xiv. 358; Gerh. iii. 621). A crystalline substance 
 obtained from the Laurus camphora and other plants in which it exists ready formed. 
 There are three modifications of it, identical in composition and chemical properties, 
 but differing in their action on polarised light, viz. dextro-camphor, which turns the 
 plane of polarisation to the right, l&vo-camphor, which turns it to the left, and inactive 
 camphor, which has no action on polarised light. 
 
 o. Dextro-camphor. Laurel or common camphor. This variety exists in the wood 
 and bark of several trees of the Lauraceous order, chiefly in the Laurus camphora, a 
 tree indigenous in Japan, Java, Sumatra, and Borneo. The process of extraction is 
 very simple. In China and Japan, the wood, sawn into billets, is distilled with water 
 in a kettle covered with an earthen capital lined with rice-straw, on which the crystals 
 of camphor are deposited, being carried up by the aqueous vapour. The crude 
 camphor thus obtained is exported to Europe, where it is purified by sublimation. In 
 Sumatra and Borneo, the wood is split with wedges, and the camphor, which is found 
 between the fibres in tears and crystals, is extracted ; a single tree sometimes yields 
 as much as twenty pounds. 
 
 Dextro-camphor is also produced artificially by the action of nitric acid on borneol 
 or camphor of Borneo, C 10 H 18 (pp. 626, 726). 
 
 Camphor crystallises by sublimation, or by slow deposition from an alcoholic solution, 
 in octahedrons or segments of octahedrons. It is white and semi-transparent, like ice, 
 rather tough, sectile, and not easily reduced to powder without the aid of a little 
 alcohol. It melts at 175C. and boils at 204 C. evaporating completely away without 
 alteration. Its specific gravity varies from 0'986 to 0'996. Vapour- density = 5 '3 17 
 (Dumas). Water dissolves y^ pt. of camphor, and thereby acquires its peculiar 
 smell and taste. When small bits of camphor are thrown into water in a broad basin, 
 they revolve and move about with more or less velocity, in proportion to their small- 
 ness. These rotations are attributed to the force exerted by the vapours rapidly ex- 
 haled from the camphor on the surface of the water ; but the explanation is not very 
 satisfactory. If a pin-point slightly smeared with oil be dipped into the water, all 
 the motions cease instantly, and the particles of camphor are repelled from the pin-spot 
 by the spreading film of oil. The dispersion of the camphor- vapour is made very 
 striking by the repulsion of the water on a moistened saucer from the points on which 
 bits of this substance are laid. 
 
 Laurel-camphor is soluble in alcohol, ether, acetone, acetic acid, wood-spirit, sul- 
 phide of carbon, and oils. 100 pts. of alcohol of specific gravity 0'806 dissolve 120 pts. 
 of camphor. It is thrown down almost entirely in flocks by the addition of water. 
 Camphor augments in a remarkable degree the solubility of corrosive sublimate in 
 spirit of wine. 
 
 The optical rotatory power of the alcoholic solution of camphor, is 47 4 for a length 
 of 100 millimetres. According to Arndtsen (Ann. Ch. Phys. [2] liv. 403), it increases 
 with the refrangibility of the rays much more quickly than is observed in any other 
 substance. Solid camphor does not exhibit any rotatory power. 
 
 Reactions. 1. Camphor, when set on fire in the air, burns with a smoky flame, pro- 
 ducing water and carbonic acid. Spongy platinum, or a coil of fine platinum wire laid 
 on camphor, begins to glow when the camphor is set on fire, and continues glowing 
 after the flame is blown out. Camphor is set on fire by chlorochromic acid. 2. By 
 prolonged boiling with nitric acid or permanganate of potassium, it is converted into 
 camphoric acid (p. 730). 3. Heated with strong sulphuric acid to 100 C. for 1213 
 hours, it is converted into camphrene, C 8 H I2 0, with evolution of sulphurous anhydride 
 and separation of charcoal (Chautard, Compt. rend. xliv. 66). According to Dela- 
 lande (Instit. 1839, p. 399), camphor heated with excess of strong sulphuric acid, is 
 converted into a volatile oil, which has the chemical properties and composition of 
 common camphor, but less rotatory power, and when heated with potash to nearly 
 200 C. is converted into a solid camphor, whose rotatory power is intermediate be- 
 tween that of common camphor and that of the oily camphor. Gerhardt supposed that 
 the oil obtained by Delalande was cymene ; according to Chautard, it is camphrene 
 containing camphor. 4. Camphor-vapour passed through a red-hot glass or porcelain 
 tube, yields a combustible gas and an oil soluble in alcohol (Saussure). 5. When 
 the vapour of camphor is passed over red-hot iron, an oily liquid is produced, contain- 
 ing naphthalene and a hydrocarbon boiling at 140 C. and having the composition 
 of benzene (D'Arcet, Ann. Ch. Phys. [2] Ixvi. 110). 6. Camphor distilled with 
 
 3 A 4 
 
728 CAMPHOR. 
 
 2 pts. alumina or clay, is resolved into carbonic anhydride, carburetted hydrogen, 
 empyreumatic oil, and a residue of charcoal. 7. Distilled with phosphoric anhydride, 
 it is resolved into water and cym ene, C 10 H 14 (Delalande, Ann. Ch. Phys. [3] i. 368). 
 Heated with concentrated phosphoric acid, it volatilises for the most part undecom- 
 posed. It is also resolved into water and cymene by distillation with chloride of zinc. 
 8. Camphor-vapour passed over red-hot lime, yields camphrone, C^H^O, an oily 
 liquid boiling at 75 C. At a very bright red heat, this product is resolved into carbonic 
 oxide, carburetted hydrogen, and naphthalene (Fremy, Ann. Ch. Phys. lix. 16). 
 9. When the vapour is passed over heated potash-lime, underpressure, campholate 
 of potassium, C 10 H 17 KO 2 is produced (Delalande, p. 726). 10. Camphor heated 
 to 180 200 C. with alcoholic potash or soda, is converted into borneol (Bert he- 
 lot, pp. 626, 726). 11. When camphor is triturated with iodine, and the mixture is 
 distilled, a dark-coloured oily liquid passes over, containing camphin, campho- 
 creosote, and colophene, and a blackish residue is left, containing campho-resin 
 ;Clauss, p. 725). 12. Bromine unites with camphor, forming an instable bromide o 
 camphor, C 10 H 16 O.Br, which is crystalline, and is decomposed by heat, by contact witu. 
 air, and by the action of ammonia. 13. Chlorine exerts but little action on camphor, 
 even in sunshine. 14. With pentachloride of phosphorus, camphor yields oxychloride 
 of phosphorus, and a crystalline substance, C 10 H 16 CP, having the aspect of artificial 
 camphor (hydrochlorate of turpentine-oil). It remains dissolved in the oxychloride, 
 and may be precipitated by water (G-erhardt) : 
 
 C io H i6 + PC1 5 = POC1 8 + C ">H 16 C1 2 . 
 
 This compound yields by repeated dry distillation, a chlorinated oil consisting of 
 C )0 H 15 C1. (G-erhardt.) 
 
 According to PYaundler (Ann. Ch. Phann. cxv. 29), 1 at. camphor heated to about 
 110 C. with 1 at. PCI 5 , yields hydrochloric acid, oxychloride of phosphorus, and chlo- 
 rocamphene, C 10 H 15 C1, which is a white, soft, crystalline substance, having an odour 
 of camphor. Its index of refraction is 1-49327. It is insoluble in water, but dissolves 
 in 3'5 pts. of 87 per cent, alcohol at 14 C., forming an optically inactive solution. The 
 crystals volatilise rather quickly at ordinary temperatures, melt at about 60 C., and 
 then sublime, decomposing at higher temperatures. With 2 at. pentachloride of phos- 
 phorus to 1 at. camphor, chloride ofcamphene, C 10 H :6 C1 2 , is obtained in white 
 crystals, resembling the preceding in aspect and in odour, but softer, and having an 
 index of refraction = 1*50553. It dissolves in 4 '95 pts. of 87 per cent, alcohol, at 
 14 C., forming a solution possessing laevo-rotatory power. The crystals volatilise 
 rather quickly at ordinary temperatures, and melt with partial sublimation near 70. 
 15. If chlorine be passed through the solution of camphor in trichloride of phos- 
 phorus, various substitution-products are formed, according to the time for which the 
 action of the chlorine is continued. Tetrachlorocamphor, C 10 H 12 C1 4 2 , has been 
 isolated, though not quite pure. If the action be continued for a long time, and assisted 
 by heat, a colourless product is at length obtained, having the aspect of white wax, 
 and consisting of sexchloro-camphor, C 10 H 10 C1 6 (Glaus, J. pr. Chem. xxv. 259). 
 16. When camphor is heated with mercuric chloride, hydrochloric acid is evolved, 
 together with an odour of turpentine, and a carbonaceous mass containing calomel 
 remains. 17. Pentachloride of antimony attacks camphor strongly, giving off hydro- 
 chloric acid, and forming a resinous substance. 18. Hydrochloric acid gas is absorbed 
 by camphor in quantities varying according to pressure and temperature, as shown by 
 the following table, which gives the quantity of the gas (HC1) absorbed by 100 pts. 
 camphor, at the temperature t and barometric pressure b : 
 
 t 24 20 18-5 18-5 13 9 7 7 3 3 C. 
 
 b 747 740 735 744 320 288 270 740 232 738 mm. 
 HC1 19-0 20-0 20-4 20'5 15*3 15*8 16-3 240 17'0 26'0 
 
 At a certain low pressure, camphor no longer absorbs hydrochloric acid gas. This 
 pressure varies with the temperature, being 220mm. at 12; 340mm. at 15*0; 
 300mm, at 20 ; and 423mm. at 24 (Bineau, Ann. Ch. Phys. [3] xxiv. 328). 
 19. Sulphurous anhydride is quickly absorbed by camphor, forming a colourless liquid, 
 which is heavier than water, dissolves iodine and camphor, and when saturated with 
 camphor, contains 4 pts. camphor to 1 pt. SO 2 . It gives off sulphurous anhydride even 
 at ordinary temperatures. The quantities absorbed by 100 pts. camphor at various 
 pressures and temperatures, are given in the following tables (Bineau, loc. cit.) : 
 
 t 24 24 15-5 15-5 12-5 12-5 2 8 4 4 2 2 C. 
 b 524 745 355 744 529 727 304 682 490 720 649 650 mm. 
 SO 2 25-5 35-4 28'0 47'6 37'3 50-5 33'0 57'4 46'0 73'6 48'4 72'0 
 
CAMPHOR, ARTIFICIAL CAMPHOR AMIC ACID. 729 
 
 At 700 mm. pressure, 100 pts. camphor absorb of SO 2 : 
 
 at 24 20 15-5 14 12'5 10 8 4 C. 
 33-1 37-7 44-3 46'8 48'9 54'0 58'6 70'5 
 
 20. Camphor absorbs the vapour of peroxide of nitrogen (or nitric oxide in presence 
 of air), forming a liquid which is decomposed by water, dissolves camphor, and 
 when saturated therewith at 18 C., contains 100 camphor to 26 27 peroxide of 
 nitrogen. (B i n e a u. ) 
 
 0. Lcevo-camphor.When the essential oil of feverfew (Pyrcthrum parthenium) 
 is fractionally distilled, and the portion which distils between 200 and 220 C. is col- 
 lected apart, it deposits on cooling a large quantity of camphor, similar in all respects 
 to common camphor, excepting in its optical rotatory power, which is equal and oppo- 
 site, viz. [a] = 47'4 for a length of 100 millimetres. The camphor treated with 
 nitric acid yields Isevo-camphoric acid. (Dessaignes and Chautard, J. Pharm. [3] 
 xiii. 241 ; Chautard, Compt. rend, xxxvii. 166.) 
 
 y. Inactive Camphor. According to Proust, the essential oils of several labiate 
 plants, viz. rosemary, marjoram, lavender, and sage, often deposit a substance like 
 camphor. Lavender camphor has the same composition as laurel camphor, but is with- 
 out action on prolonged light. (Dumas, Ann. Ch. Phys. xiii. 275; Biot, Compt. 
 rend. xv. 710.) 
 
 Bodies resembling camphor but of undetermined modification, have been obtained 
 by the action of nitric acid on the essential oils of tansy, semen-contra, valerian, and 
 sage. Lastly, when amber is treated with nitric acid, it yields a distillate containing 
 camphor, which may be extracted by saturating with carbonate of potassium and 
 igniting with ether. 
 
 CAMPHOR, ARTIFICIAL Syn. with HYDROCHLORATE OF TURPENTINE-OIL, 
 (See TURPENTINE.) 
 
 CAMPHOR OF BORNEO. See BORNEOL. 
 
 CAMPHOR, OIIi OP. When the branches of the camphor-tree (Laurus cam- 
 phora} are distilled with water, a volatile oil passes over together with camphor. 
 This oil is mobile, colourless, has a strong odour of camphor and considerable dextro- 
 rotatory power, and is resolved by fractional distillation into an oil boiling at 180 C. 
 and a portion boiling at 205 ; the latter appears to be essentially the same as common 
 camphor. The oil boiling at 180 is very much like oil of lemon, possesses strong 
 dextro-rotatory power, and forms with hydrochloric acid a crystalline compound, which 
 melts at 42, and gives by analysis 57'34 per cent. C, 8*6 H, and 33'83 Cl, agreeing 
 with the formula C 10 H 16 .2HC1. (Lallemand, Ann. Ch. Phys. Ivii. 404.) 
 
 The wood of Dryabalanops Camphora, from which borneol is obtained, likewise yields 
 by boiling with water, a camphor oil, separable by fractional distillation into two vola- 
 tile oils, having the composition C 10 H 16 , one boiling between 180 and 190 C., the 
 other at about 260, and a resin, C 30 H 46 2 (?), which melts at a temperature a little 
 above 100 (Lallemand). It is remarkable that the oil of Dryabalanops examined 
 by Lallemand, did not contain borneol, and that even the most volatile portion of it 
 had a boiling point much higher than that of borneene (p. 626). The subject requires 
 further examination. (See DRYABALANOPS.) 
 
 C"H"NO> = N.H*.(C'H"OT( . (Laurent, 
 
 CAMPHORAMIC ACID. 
 
 Compt. chim. 1845, p. 147.) Derived from acid camphorate of ammonium by elimi- 
 nation of 1 at. water: 
 
 C 10 H 15 (NH 4 )0 2 - H 2 = C 10 H 17 N0 3 . 
 
 The ammonium-salt of this acid is produced by the action of ammonia on a boiling 
 saturated solution of camphoric anhydride (C'H 14 3 + 2NH 3 = C'H I6 (NH 4 )N0 3 ), and 
 on treating the solution of this salt with hydrochloric acid and evaporating, campho- 
 ramic acid is deposited in crystals, which may be purified by solution in dilute alcohol 
 and spontaneous evaporation. It is then obtained in splendid crystals, belonging to 
 the trimetric system, oo P oo . ooP oo . P oo, with ooP and P subordinate. Inclination 
 of the faces: Poo : Poo =114 30'; Poo : oo*>oo = 122 45'; Poo : P = 155; ooPoo : 
 ooP 131 40'. It is colourless, moderately soluble in hot water, less in cold ; more 
 easily in alcohol. A small quantity melted on a plate of glass, partly crystallises in 
 rhomLs, while the rest solidities slowly into a transparent vitreous mass. 
 
 The acid is monobasic. Its ammonium-salt, C'H 16 (NH 4 )N0 3 + H'-O, crystallises 
 well, has a slightly acid, bitter, transient taste, and melts at 100 C. It differs from 
 neutral camphorate of ammonium, with which, in the hydrated state, it agrees in 
 composition, by not precipitating the salts of lead, copper, or silver. The lead-salt, 
 C 10 H 1(i PbN0 3 , is deposited in small crystals, on mixing the concentrated boiling alco- 
 
730 CAMPHORANILIC ACID CAMPHORIC ACID. 
 
 holic solutions of camphoramate of ammonium and acetate of lead, the former in excess, 
 and leaving the liquid to cool. The silver-salt^ C 10 H l6 AgN0 8 , is obtained as a trans- 
 parent jelly, composed of minute crystals, on mixing the boiling concentrated solutions 
 of camphoramate of ammonium and nitrate of silver, and leaving the liquid to cool. 
 
 CAlVXPHORANIXiXC ACID. See PHENYL-CAMPHOBAMIC ACID. 
 
 CAMPHORA1KXDE. C 10 H 18 N 2 2 = N 2 .H 4 .(C'H 14 2 )". When a current of 
 ammonia-gas is passed into the middle of a solution of camphoric anhydride in abso- 
 lute alcohol, the liquid becomes heated, and yields by evaporation a syrupy mass, in- 
 soluble in water, which is probably camphoramide. It is not decomposed in the cold 
 by hydrochloric acid ; but when treated with potash, it gives off ammonia, and forms 
 camphorate of potassium, (Laurent, Rev. scient. x. 123.) 
 
 C AlttPHORESINT. The name given by Glaus to the non-volatile product of the 
 action of iodine on camphor (p. 728). 
 
 CAMPHORIC ACID. C 10 H 16 4 C 10 H 14 2 .H 2 .0 2 . (Gm. xiv. 455 ; Gerh. iii. 
 700.) There are three modifications of this acid, corresponding to those of camphor, 
 viz. dextro-rotatory, Icevo-rotatory, and inactive. 
 
 Dextro-camphoric or ordinary Camphoric acid. This acidwas discovered by 
 Kosegarten (Diss. decamphpra etpartibus qua earn constituent, Gottingen, 1785), and 
 particularly studied by Laurent (Ann. Ch. Phys. Ixiii. 207 ; Compt. Chim. 1845, 
 p. 141), M'alaguti (Ann. Ch. Phys. Ixiv. 151), and Liebig (Ann. Ch. Pharm. xxii. 
 50). To prepare it, common camphor is heated in a retort with ten times its weight 
 of strong nitric acid, the liquid being cohobated several times, and the acid renewed. 
 On evaporating and cooling the residual liquid, the camphoric acid crystallises out, and 
 may be purified by dissolving it in carbonate of potassium, precipitating with nitric 
 acid, and recrystallising several times. 
 
 Camphoric acid forms colourless transparent scales or needles, which melt at 70 C., 
 and taste sour and bitter at the same time. It is sparingly soluble in cold water, more 
 readily in boiling water ; easily also in alcohol, ether, and fatty oils. According to 
 Brandes, it requires for solution, 88*8 pts, of water at 12-5 C., and 8*6 pts. at 96-25. 
 Molecular rotatory power of the solution [a] = + 38*875 ; this power diminishes con- 
 siderably on saturating the acid with an alkali. 
 
 It gives an abundant precipitate with neutral acetate of lead. By dry distillation 
 it is resolved into water and camphoric anhydride, leaving only a small film of charcoal. 
 It dissolves without alteration in strong nitric and sulphuric acid. 
 
 )8. ,L(Svo-camphoric Acid. Obtained by the action of nitric acid on the camphor 
 of feverfew (p. 729), has the same composition and chemical properties as dextro-cam- 
 phoric acid, and rotates the plane of polarisation, by exactly the same amount, to the 
 left. (Chautard, Compt. rend, xxxvii. 166.) 
 
 7. Inactive Camphoric Acid, or Paracampkoric Acid, ,is produced by mixing equal 
 weights of dextro- and Isevo-camphoric acid. It agrees with ordinary camphoric acid 
 in most of its properties, but has no action on polarised light. (Chautard.) 
 
 CAMPHORA.TES. Camphoric acid is dibasic, the formula of a neutral camphorate 
 being C 10 H 14 M 2 4 . The camphorates are odourless, and have a slightly bitter taste. 
 Most of them are sparingly soluble in water. They are decomposed by sulphuric, 
 hydrochloric, and nitric acid. 
 
 Camphorates of Ammonium. The neutral salt, C 10 H 14 (NH 4 ) 2 4 , is obtained by 
 passing a current of dry ammonia-gas over camphoric acid, and exposing the product 
 to a current of dry air. It is very soluble in water, and has a slight acid reaction, but 
 no decided taste. An acid ammonium-salt is obtained in small prisms, melting above 
 100 C. by throwing crystals of acid carbonate of ammonium into a boiling solution of 
 camphoric acid. When dried at 100 in a current of air, they lose 19 per cent, of 
 water. They contain, according to Malaguti, 53'57 per cent, carbon, 8*97 hydrogen, 
 and 8-5 nitrogen, whence he deduces the formula 3C 10 H I6 4 .4NH 3 + 9H*0, that is to 
 say, a compound of 1 at. neutral camphorate and 2 at. acid camphorate of ammonium ; 
 but, according to Gerhardt, the salt is an acid camphorate, O^H^NH^O + 3H 2 0, the 
 formula of which requires 55-3 C, 87 H, 6-6 N, and 19 -9 per cent, water. 
 
 Camphorate of Potassium. C 10 H I4 K 2 4 . Crystallises in large nacreous scales when 
 prepared with hydrated camphoric acid, and in small delicate needles when prepared by 
 dissolving camphoric anhydride in potash. According to Bucholz and Bouillon- 
 Lagrange, it is but sparingly soluble in water, whereas Brandes states that it is very 
 deliquescent, and dissolves in a very small quantity of water (probably the sparingly 
 soluble salt was an acid salt). Camphorate of sodium forms limpid, confused, slightly 
 efflorescent crystals, soluble in 200 pts. of cold and 8 pts. of boiling water ; also in 
 alcohol. 
 
 The barium-salt forms laminae or needles soluble in 600 pts. of boiling water ; ac- 
 cording to Brandes, in 1*8 pts. water at 19-9 C. 
 
CAMPHORIC ANHYDRIDE CAMPHORIC ETHERS. 731 
 
 The strontium-salt forms colourless laminse much more soluble than the barium- 
 salt. 
 
 Calcium-salt. The neutral salt forms a non-crystalline mass, neutral to test-paper, 
 nearly insoluble in cold water, soluble in 200 pts. of boiling water, insoluble in alcohol, 
 and containing 7 per cent, water of crystallisation. It falls to powder in contact with 
 the air. By treating carbonate of calcium with camphoric acid, a salt is obtained 
 having an acid reaction, and crystallising in rhomboi'dal prisms, containing 37'5 per 
 cent, water, and soluble in 5 pts. of cold water (Bucholz, Brandes). Neutral cam- 
 phorate of calcium yields, by dry distillation, carbonate of calcium and camphorone : 
 
 C">H 14 .Ca 2 4 = COW + C 9 H0. 
 
 Camphorate of Copper, C 10 H 14 Cu 2 4 (at 100), is obtained by double decomposition 
 as a light green precipitate, nearly insoluble in water. It forms a crystallisable com- 
 pound with ammonia. 
 
 Camphorate of Manganese is very soluble in water. Manganous salts are not pre- 
 cipitated by alkaline camphorates. 
 
 Mercurous Camphorate is a white precipitate, nearly insoluble in water. 
 
 Camphorate of Silver is a white fusible precipitate, which becomes coloured by ex- 
 posure to light. 
 
 CAMPHORIC ANHYDRIDE. Anhydrous camphoric acid. C'H 14 2 .0. 
 
 prisms 
 
 without acid reaction, and having no perceptible taste at first, but afterwards irri- 
 tating to the throat. It dissolves very sparingly in cold water, a little more in boiling 
 water, very abundantly in alcohol, still more in ether. At 130 C. it begins to sublime 
 in beautiful white needles, melts to a colourless liquid at 217, begins to boil above 
 270, and distils without residue. Specific gravity of the crystals 1-194 at 20'5. They 
 become electric by friction, like resins. Their solution does not precipitate neutral 
 acetate of lead. 
 
 Camphoric anhydride boiled with water dissolves very slowly as camphoric acid. 
 The transformation is effected much more quickly by alkalis. It does not absorb dry 
 ammonia gas, but aqueous or alcoholic ammonia converts it into camphoramate of 
 ammonium. Heated with phenylamine, it yields phenylcamphoramate of phenylam- 
 nionium and phenylcamphorimide. Heated with strong sulphuric acid, it gives off 
 carbonic oxide, and is converted into sulphocamphoric acid (q. v.) 
 
 C 10 H I4 3 + H 2 SO* = C 9 H 16 S0 8 + CO 
 
 Camphoric Sulpho- 
 
 anhydride. camphoric 
 
 acid. 
 
 CAMPHORIC ETHERS. Camphorate of Ethyl. C 14 H 24 4 = C'H U 
 (C 2 H 5 ) 2 .0 4 . This body is formed in the dry distillation of ethyl-camphoric acid, 
 and is obtained by pouring water into the alcoholic mother-liquors from which the 
 latter has been precipitated. It is purified by boiling with alkalised water, drying 
 in vacuo, then washing, distilling, and again drying in vacuo. It is an oil having a 
 faint amber colour, a very disagreeable bitter taste, and a powerful odour. Specific 
 gravity 1-029 at 16 C. Begins to boil at 285 or 287 ; turns brown a few degrees 
 higher, and leaves a black residue, but the distillate is very pure after being washed. 
 It is perfectly neutral and insoluble in water. Potash decomposes it like other ethers ; 
 sulphuric acid dissolves it in the cold without decomposition ; at higher temperatures, 
 decomposition takes place, but without blackening or evolution of sulphurous acid. 
 It is not altered by hydrochloric or nitric acid, either cold or hot. (Malaguti, Ann. 
 Ch. Phys. Ixiv. 151.) 
 
 Tctrachlorinatcd Camphorate of ethyl, C 14 H 20 C1 4 4 , is produced by the action of 
 chlorine on Camphorate of ethyl. Neutral ; has a bitter persistent taste. Soluble 
 in alcohol and ether. Specific gravity 1-386 at 14 C. When heated it becomes very 
 fluid, and decomposes before boiling. Aqueous potash scarcely attacks it, but alcoholic 
 potash converts it into Camphorate, acetate, and chloride of potassium : 
 
 C 14 H 20 C1 4 4 + 8KHO = C'H 14 K 2 4 + 2C 2 H :) K0 2 + 4KC1 + 4H 2 0. 
 (Malaguti, Ann. Ch. Phys. Ixx. 360.) 
 
 Camphorate of Ethyl and Hydrogen. Ethyl-camphoric or Camphovinic acid 
 C' 2 H-0 4 = C 1(1 H 14 (C-IP.H)0 4 . When a mixture of 2 pts. camphoric acid, 4 pts. ab- 
 solute alcohol, and 1 pt. sulphuric acid is boiled and cohobated several times, a residue 
 is obtained, which, when diluted with water, yields an oily deposit of ethyl-camphorie 
 
732 CAMPHORIMIDE CAMPHORIN. 
 
 acid. This acid nas, at ordinary temperatures, the consistence of treacle. It is trans- 
 parent and colourless, has a peculiar odour and a very agreeable taste, not acid, but 
 bitter. It dissolves very sparingly in alcohol and ether. Specific gravity 1-095 at 
 20'5 C ; reddens litmus paper after a while only ; dissolves in alkaline solutions, but 
 is decomposed when boiled with them. Water effects the same decomposition after 
 long contact or continued ebullition. By dry distillation it yields water, camphoric 
 anhydride, and camphorate of ethyl, together with very small quantities of alcohol and 
 carburetted hydrogen gas, resulting from secondary decomposition : 
 
 2C 12 H 20 4 = H 2 + C 10 H I4 3 + C I4 H 24 4 
 
 Ethyl-catnphoric Camphoric Camphoric 
 
 acid. anhydride. ether. 
 
 The alcoholic solution gives a copious precipitate with neutral acetate of lead. (Ma- 
 laguti.) 
 
 Ethyl-camphoric acid is monobasic, the formula of its salts being C'H 14 (C 2 H 5 .M)0 4 . 
 The ammonium, potassium, sodium, barium, strontium, calcium, and magnesium-salts 
 are soluble in water. The zinc, copper, lead, mercury, and silver-salts are insoluble 
 or sparingly soluble. The copper-salt, obtained by precipitating sulphate of copper 
 with ethyl-camphorate of ammonia, is probably a sesquibasic salt. (Malaguti, Ann. 
 Ch. Phys. Ixiv. 151.) 
 
 Ca mp horateof Me thy I and Hy drogen. Methyl-camphoric or Camphomethylic 
 acid. C n H 18 4 = C 10 H 14 (CH 3 .H)0 4 . Obtained in the same manner as ethyl-cam- 
 phoric acid, substituting wood-spirit for alcohol. The residue of the third distillation 
 yields, when washed with water and left at rest, a crystalline mass, which is to be 
 pressed between paper and boiled with water. It then forms an acid liquid, at the 
 bottom of which some drops of oil collect, changing after a few days into well- 
 defined, colourless, shining crystals of methyl-camphoric acid. These crystals are 
 either needles arranged in radiating groups, or small four-sided or six-sided laminae ; 
 but on dissolving them in ether and leaving the solution to evaporate very slowly, 
 well formed prisms are obtained belonging to the trimetric system, and exhibiting 
 the combination, P . ooP . ooPoo. Inclination of the faces, ooP : ooP = 106 30'; 
 
 oo P oo : oo P = 126 45'; oo P oo : P = 115 25' and 66 4'; P : P = 160 30'. The 
 
 -p 
 
 four-sided laminae are hemihedral, and exhibit only the combination - . 8Poo , with 
 
 cleavage perpendicular to oo P oo. 
 
 Methylcamphoric acid is very little soluble in water, very soluble in alcohol, ether, 
 and chloroform. The qfc>lutions are strongly acid, and turn the plane of polarisation of 
 a ray of light to the right: [a] = + 51 4'. The acid melts at about 68 C., and re- 
 mains viscid a long time after cooling. By distillation it yields camphoric anhydride, 
 a viscid liquid, and a slight residue of carbon. Boiled with caustic potash, it gives off 
 wood-spirit and is converted into camphorate of potassium. 
 
 The aqueous and alcoholic solutions of the acid form a white crystalline precipitate 
 with acetate of lead, soluble in excess of the acetate ; with acetate of copper, a greenish 
 crystalline precipitate ; with baryta- water, they form a cloud, which disappears on add- 
 ing a drop of nitric acid. They have no action on lime-water or on soluble barium- 
 salts, but form a slight cloud with nitrate of silver. Oxide of silver is reduced by 
 them, producing a blackish deposit. (Low, Ann. Ch. Phys. xxxviii. 483.) 
 
 CAIMPHORIMIDE. C 10 H 15 N0 2 = N.H.(C 10 H I4 2 )". Obtained by heating 
 neutral camphora:nate of ammonium to 150 or 160 C., or by melting or distilling cam- 
 phoramic acid : 
 
 C 10 H"N0 3 = C'H 15 N0 2 + H 2 
 
 Camphoramic Camphorimide. 
 acid. 
 
 and: C 10 H I6 (NH 4 )N0 3 = C'H I5 N0 2 + NH 3 + H 2 0. 
 
 Camphoramate of Camphorimide. 
 ammonium. 
 
 It is purified by solution in boiling alcohol and crystallises on cooling. It is colour- 
 loss, volatilises at a high temperature without decomposition, and dissolves easily in 
 boiling alcohol, crystallising, on cooling, in tufts like fern leaves, beautifully divided ; 
 or by very slow cooling in hexagonal tables, oblique and much elongated. From a 
 solution in weak alcohol, it is gradually deposited in the form of a gummy, transparent 
 substance, which solidifies after some hours in opaque tubercles. The alcoholic solu- 
 tion gives off ammonia when boiled with potash. It dissolves at a gentle heat in strong 
 sulphuric acid, and, on pouring a few drops of water into the solution, a white crys- 
 talline deposit is formed! (Laurent, Compt. chim. 1845, p. 147.) 
 
 CAXVXPHORXir. Camphcrate of Glyceryl. Produced by heating camphoric acid 
 

 CAMPHORONE CANADA BALSAM. 733 
 
 with glycerin. Viscid ; soluble in ether ; decomposed by oxide of lead, yielding gly- 
 cerin and camphorate of lead. (Berthelot.) 
 
 CAftZPHORONE. Phorone (Grerhardt) ; Camp horyl (Laurent). C 9 H U 0. 
 This compound, the acetone of camphoric acid, was first obtained in an impure state, 
 as a product of the decomposition of that acid, by Laurent (Ann. Ch. Phys. [2] Ixv. 
 329), afterwards prepared pure and more thoroughly examined by Grerhardt and 
 Lies-Bodart (Compt. chim. 1849, p. 385.1 
 
 Camphorone is produced, like other acetones, by the dry distillation of the calcium- 
 salt of the acid : 
 
 C'H 14 O.Ca 2 .0 2 = CO.Ca 2 .0 2 + C 9 H 14 
 
 Camphorate of Carbonate of Campho- 
 calcium. calcium. rone. 
 
 It is best to operate only on small quantities at a time. The brown or yellow oil 
 which passes over is purified by fractional distillation, a small quantity of tar remain- 
 ing behind. 
 
 Camphorone is likewise obtained, together with other products, by distilling with 
 lime either of the following substances : 1. Acetic acetone, which differs from it only by 
 the elements of water (3C 3 H 6 2H*O = C 9 H 14 0). On rectifying the distillate, oxide of 
 mesityl, C 6 H I2 0, passes over at about 131 C., and camphorone between 200 and 205 
 (Fit tig, Ann. Ch. Pharm. ex. 33). 2. Grape-sugar. The distillate yields on recti- 
 fication, an oil boiling at 86 C., having the composition of metacetone, C I8 H 30 3 (and 
 converted into camphorone, or a body isomeric with it, by distillation with phosphoric 
 anhydride), while camphorone passes over at 208 (Lies-Bodart, Compt. rend, xliii. 
 
 394.). 3. The juice of ripe mountain-ash berries, which contains a small quantity of 
 
 malic acid: this method, however, does not always yield it. (Lies-Bodart, loc.cit.} 
 
 Camphorone is a colourless or yellowish oil, very mobile, lighter than water : and 
 having a. strong odour like that of peppermint. It boils at 208 C. (G-erhardt), and 
 volatilises undecomposed, yielding a vapour whose density = 4'982 > (Gerhardt and 
 Lies-Bodart), by calculation for 2 vol. = 4784. It is insoluble in water, but dis- 
 solves in alcohol and very readily in ether. It does not unite either with acids or 
 with alkalis, and according to Limpricht (Ann. Ch. Pharm. xciv. 246), differs from 
 other acetones in not combining with acid-sulphites of alkali-metals. 
 
 Camphorone becomes darker in colour when exposed to the air. It dissolves with 
 blood-red colour, in strong sulphuric acid, and is for the most part precipitated there- 
 from by water. It is resinised by nitric acid. Phosphoric anhydride acts quickly 
 upon it at a high temperature, converting it, by abstraction of water,into cumene, C 9 H 12 
 (not mesitylene), which passes over in fractional distillation at 170 C., a carbonaceous 
 mass being left behind. Pentachloride of phosphorus converts it into a chlorinated 
 oil, C 9 H 13 C1, boiling at 175 C., lighter than water, insoluble therein, easily soluble in 
 alcohol. The alcoholic solution, saturated with ammonia-gas, yielded a crystalline 
 substance, probably C 9 H I5 N.HC1 (Lies-Bodart). Camphorone heated with potas- 
 sium, gives off hydrogen, and appears to form the compound C 9 H 13 KO (Lies- 
 Bodart). With potash-lime it becomes heated, and appears to enter into combination ; 
 the mixture heated to 240 C. gives off a colourless oil, apparently different from 
 camphorone, while a resinous substance remains with the alkali. (Gerhardt and 
 Lies-Bodart.) 
 
 CAMPHORYXi. C 10 H 14 2 . The diatomic radicle of camphoric acid, &c. The 
 same term was applied by Laurent to camphorone. 
 
 CAMPHOSUXiPHITRZC ACID. See STJLPHOCAMPHORIC ACID. 
 
 C AMPHOVXWXC ACID. Camphorate of Ethyl and Hydrogen. (See CAMPHOEIO 
 ETHEBS, p. 732.) 
 
 CA1V1PHRENE. A product of the decompsition of camphor by sulphuric acid 
 (p. 728). 
 
 CAIVIPHROMrE. C 30 H 44 0. A liquid produced by passing camphor over red-hot 
 lime. It is a light oil, having a strong and peculiar odour, quite different from that 
 of camphor. It boils at 75 C., is insoluble in water, soluble in alcohol and in ether. 
 It is produced from camphor by abstraction of water (3C'H 16 - 2H 2 = C 30 H 44 0), 
 and is perhaps identical with the product obtained by heating camphor with clay, or 
 by passing the vapour of camphor through a red-hot porcelain tube. (Fremy, Ann. 
 Ch. Phys. [2] lix. 16.) 
 
 CAM-WOOD. See BABWOOD (p. 517). 
 
 CAXTAAXTXTE. A greyish scapolite rock, from Canaan, Connecticut, containing 
 63-37 per cent. SiO 2 , 4'10 Fe 4 3 , 10-38 A1 4 3 , 25-80 Ca 2 0, 1-62 M^O, and 4'00 CO 2 . 
 (Dana, ii. 203.) 
 
 CAM-ADA BAX.S AM. See BALSAMS (p. 492). 
 
734 
 
 C ANCERIN C ANNABIN. 
 
 CANCERICT. An artificial guano from Newfoundland. 
 
 CAIO-CHA-X.AGVA. See CACHA-LAouA (p. 701). 
 
 CANCRINTTE. A massive mineral found near Miask in the Ural, in the Miiriins- 
 kaja mine in the Tunskinsk mountains, Siberia, and in Litchfield in the State of Maine. 
 It cleaves parallel to the faces of a hexagonal prism, has an uneven fracture, light rose- 
 red colour and waxy lustre, nacreous on the cleavage faces ; transparent or strongly 
 translucent. Specific gravity 2 P 45 to 2'46. Hardness 5'0 5'5. It melts to a white 
 tumefied glass. Hydrochloric acid dissolves it readily, with efflorescence and separa- 
 tion of gelatinous silica. 
 
 The following are analyses of cancrinite: 1. From Miask; light red: a. Specific 
 gravity 2-453 (G.Rose, Pogg. Ann. xlvii. 375); b. Specific gravity 2-489 (Pusi- 
 rewsky, Kokscharow's Materialen zur Mineralogie Russlands, i. 81). 2. From the 
 Tunskinsk Mountains, yellow; a. Specific gravity 2-449 (Struve, Pogg. Ann. xc. 
 613); b. Specific gravity 2*448 (Pu.sirewsky). 3. From Litchfield. a. Yellow. 
 Specific gravity 2-448 ; b. Greenish. Specific gravity 2'461. (Whitney, ibid. Ixx. 
 431.) 
 
 From Miask. From the Tunskinsk Mts. From Maine. 
 
 G. Rose. 
 
 Pusirewsky. 
 
 Silica . . . 6-38 
 
 5-55 
 
 Carbonic anhydride 
 Alumina . 
 
 40-4.3 
 28-227 
 
 35-96 
 29-57 
 
 Ferric and Manganic ) 
 oxides j 
 
 - 
 
 0-19 
 
 Lime 
 
 
 6-;o 
 
 5-68 
 
 S..da 
 
 
 17-52 
 
 18-53 
 
 Potash . 
 
 
 0-70 
 
 
 
 Water . 
 
 
 _ 
 
 369 
 
 SO 3 0-32 
 
 Struve. 
 
 8-51* 
 38-33 
 
 28-55 
 
 4-24 
 20-37 
 
 Pusirewsky. 
 5-61 
 3772 
 27-27 
 
 3-11 
 
 21-60 
 
 4-07 
 
 Whitney. 
 
 Whitney. 
 
 5-95 
 37-72 
 27-55 
 
 5-92 
 37-20 
 27-59 
 
 0-75 
 
 0-27 
 
 3-87 
 20">7 
 0-67 
 2-82 
 
 5-26 
 
 20-46 
 0-50 
 3-28 
 
 99-49 
 
 100-48 
 
 From these results, Rammelsberg concludes that the mineral is a mixture of car- 
 bonate of calcium with elseolite, containing a smaller proportion of potash and more 
 water than the usual amount. (Bammelsberg's Mineralchemie, p. 653; Dana, ii. 
 232.) 
 
 CAZTBITE. See SPINEL. 
 
 AXiBA. Costus dulcis. White Cinnamon. These names are ap- 
 plied to the bass or inner bark of Canella alba, a canellaceous tree growing in the West 
 Indies, especially in Jamaica. It forms reddish-yellow tubes, three feet long and an 
 inch thick, having a pleasant aromatic taste and odour : it contains about 8 per cent. 
 of manna (formerly mistaken for a peculiar kind of sugar called cancllin), besides 
 starch and the other usual constituents of vegetable structures. By distillation with 
 water, it yields two volatile oils, one lighter than water, the other heavier. If these 
 oils be left in contact with potash-ley, the liquid then diluted with water and distilled, 
 the first portion of the distillate is again lighter than water, and at last a heavy oil is 
 obtained, of very peculiar odour. The potash-ley from which the oils have been dis- 
 tilled, yields by neutralisation with acid and distillation, a heavy oil, smelling like oil 
 of cloves. The light oil of white cinnamon smells very much like oil of cajeput. It 
 may be separated by fractional distillation into several oils, differing greatly in boiling 
 point. White cinnamon contains about 6 per cent, of ash, consisting mainly of car- 
 bonate of calcium. (Handw. d. Chem. ii. [2] 927.) 
 
 CAira-AMXWE. Syn. of BRUCIKJE. 
 
 C Aior ABIIST. A poisonous resin extracted from hemp, by exhausting the bruised 
 plant ( Gunjah) with alcohol, after the greater part of the brown colouring matter lias 
 been removed by digestion, first in tepid water, afterwards in solution of carbonate of 
 sodium, then precipitating the chlorophyll with lime, decolorising withanimal charcoal, 
 and evaporating. (T. and H. Smith, Pharm. J. Trans, vi. 127, 171.) 
 
 From the Extract, hb. canab. ind. spiritless. G. Martius has prepared a resin, by 
 treating it with cold alcohol of 83 per cent., mixing the dark green filtrate with water 
 till turbidity ensues, agitating with animal charcoal, filtering and distilling off the 
 alcohol : the resin then separates. It is a light brown, shining substance, becoming 
 glutinous and ductile, has a peculiar narcotic odour, like that of the extract, and an in- 
 tensely bitter taste. It melts at 68 C., burns with a bright smoky flame, is insoluble 
 in potash and ammonia, but dissolves in alcohol and ether, sparingly also in acids. 
 Volatile oils dissolve it in the cold ; fixed oils, with aid of heat. 
 
 The narcotic effects of haschish (q. v.} are due to hemp-resin. (Handw. d. Chem. ii. 
 [2] 727.) 
 
 * Carbonic anhydride and water. 
 
CANNABIS INDICA CANTHAKIDIN. 735 
 
 CAlfiNABIS INDZCA. Indian Hemp. Tliis plant, which is indigenous in 
 India and Asia Minor, is much used in the East as an intoxicating agent ; the narcotic 
 action appears to reside essentially in a resinous exudation (see CANNABIN and 
 HASCHISH). According to Martius (Chem. Centr. 1856, 225), the herb contains a 
 small quantity of essential oil. The herb dried at 100 C. yielded 181 per cent, ash, 
 which, after deduction of carbonic anhydride and sand, contained in 100 pts. : 13'6 
 potash, 1-4 soda, 32'0 lime, 10-4 magnesia, 8'8 phosphate of iron, lO'l phosphoric an- 
 hydride, 0'3 sulphuric anhydride, 1*2 chlorine, and 22'1 silica. 
 
 CANNABIS SATIVA. Common hemp. The leaves of this plant contain 40*5 
 per cent, carbon, 5'9 hydrogen, 1'8 nitrogen, and 22-0 ash ; the stems : 39'9 per cent. C, 
 5-0 II, 17 N, and 4-5 ash. (Kane, J. pr. Chem. xxxii. 354.) 
 
 Reich (Jahresber. d. Chem. 1850, Tafel C. p. 661), found in the hemp-plant 4-6 
 per cent, ash ; in the seed 6*3 per cent. The analyses of the ash of the entire plant 
 and of the seed, are given in the following table : 
 
 K 2 Na 2 Ca 2 Mg 2 A1 4 3 Fe 4 3 SO 3 SiO 2 P 2 5 Cl CO 2 
 
 Plant (Kane) 7'5 07 42-0 4-9 0'4 1-0 67 3'2 1-5 31'9 
 
 (Keich) 15-8 3-4 35'5 77 M 27 77 14-2 3'4 8'4 
 
 Seed (Keich) 18'5 0'8 20'2 10*2 1-2 0'2 9'6 37'6 O'l 1-3 
 
 According to Leuchtweiss (Ann. Ch. Pharm. 1. 416), hempseed yields 5 - 6 per cent, 
 ash, containing 20'8 K 2 0, 0-6 Na 2 0, 25'6 Ca 2 0, 1-0 Mg 2 0, 33'5 P 2 5 , 13-5 SiO 2 , 6-2 
 sand and charcoal, and small quantities of sulphuric acid, chloride of sodium, and ferric 
 oxide. 
 
 Hempseed yields 31'8 percent, oil, 22*6 albumin, and 6*37 ash, of which 2-47 con- 
 sists of phosphates (Anderson, Highland Agr. Soc. Journal [new series] No. 50). 
 The oil is C n H"0 2 , and yields with chlorine and bromine, the substitution-products 
 C M H-C1-'0 2 , and C n H 20 Br ? 2 . (Lefort, Compt. rend. xxxv. 134.) 
 
 The leaves, flowers, and pollen of hemp have been examined by Schlesinger, 
 (Rep. Pharm. Ixxi. 190). The ash of the leaves contains 8*0 per cent, soluble, and 
 9-2 per cent, insoluble salts. (Kane.) 
 
 C ANNEX, COAX.. See COAL. 
 
 CAN-WON 1 MET AX.. See COPPER, ALLOYS OF. 
 
 CANTHARXXtES. Spanish Flies (Lytta vesicatoria.} These coleopterous in 
 sects, so well known for their vesicating properties, are much used in medicine in the* 
 form of tincture, plasters, &c. Their vesicating power is due to a peculiar acrid 
 principle called cantharidin. Taken internally, they act as a powerful aphrodisiac, 
 and may even destroy life. According to Thoury (J. Pharm. Jan. 1858, p. 65), their 
 poisonous effects may be counteracted by the administration of animal charcoal. 
 
 When the aqueous extract of cantharides is treated with alcohol, cantharidin is dis- 
 solved, together with other substances, and a brown nitrogenous substance remains. 
 On evaporating the alcoholic extract and treating the residue with ether, the cantha- 
 ridin dissolves, together with a yellow substance, and an extractive matter remains, 
 which reddens litmus and contains lactic acid, together with a nitrogenous substance. 
 The aqueous decoction of cantharides reddens litmus strongly, and gives with ammonia 
 a precipitate of ammonio-magnesian phosphate (Rob iquet, Ann. Ch.lxxvi. 302). When 
 the insects, after being exhausted with boiling water, are treated with boiling alcohol, 
 a greenish fatty oil dissolves, destitute of vesicating power, and consisting, according to 
 Gossmann (Ann. Ch. Pharm. Ixxxvi. 317), of olein, stearin, and palmitin. 
 
 CANTHARXXtXN. C 5 H 12 2 . Isomeric with picrotoxin. (Rob iquet, loc. tit.; 
 Regnault, Ann. Ch. Phys. [2] Ixviii. 151; Thierry, J. Pharm. xxi. 44; Warner, 
 Amer. J. Pharm. xxviii. 193 ; Procter, Pharm. J. Trans, xxi. 44.) This substance, 
 which is the active principle of the Spanish fly, is likewise found in the following 
 coleopterous insects : Lytta vittata, L. ruficollis, L. gigas;Mylabris cichorii (Chinese 
 cantharides), M. pustulata, M. punctum, M. Sida, M. Schoenherri ; Meloe violaceus, 
 M. autumnalis, M. Furca, M. punctatus, M. variegatus, M. scabrosus, M. majalis. 
 According to Warner, Jjytta vesicatoria, L. vittata, and Mylabris cichorii contain about 
 0'4 per cent, of cantharidin. According to Ferrer, Mylabris punctatus contains 0-33 
 per cent, M. punctum 0'19, M. cichorii O'lO, M. Sida 0'12, M. 8choenherrii 0'15 per 
 cent. 
 
 Cantharidin is prepared from Spanish flies, or better from Mylabris cichorii, inas- 
 much as this insect contains less fat, by digesting the pulverised insects for some 
 days with ether, ether-alcohol, or alcohol alone ; completing the extraction in a dis- 
 placement apparatus, the ether or alcohol being ultimately displaced by water ; and 
 distilling off the ether or alcohol. The cantharidin, which crystallises out on cooling, 
 is redissolved and purified with animal charcoal. Ether is preferable to alcohol for 
 
736 CANTONITE C AOUTCHIN. 
 
 the preparation, since it dissolves less of a green oil, which adheres obstinately to the 
 cantharidin (T hi erry). According to Procter, cantharidin is best extracted by chloro- 
 form. The pulverised cantharides are left in contact for some time with twice their 
 weight of chloroform in a displacement apparatus ; the chloroform is then drained off, 
 and finally displaced by alcohol, and the solution is left to evaporate, whereupon the 
 cantharidin crystallises out, saturated with the green oil. It is laid on bibulous paper, 
 which absorbs the greater part of the oil, then crystallised from chloroform mixed 
 with alcohol. 
 
 Pure cantharidin forms colourless right-angled four-sided prisms of the dimetric 
 system, acuminated with four faces resting on the lateral faces. According to Procter, 
 it crystallises from ether in oblique four-sided prisms, with dihedral summits, having 
 the aspect of micaceous laminae. It melts at 200 C., and volatilises in white fumes, 
 which strongly irritate the eyes, nose, and throat, and condense in rectangular prisms, 
 having a strong lustre, and sometimes iridescent. 
 
 Cantharidin per se is insoluble in water, but it is rendered soluble by the presence of 
 other substances (see the last article). It volatilises in small quantity at 104 C., and 
 more quickly at 182 ft ; not with vapour of water. It dissolves readily in alcohol, in 34 
 pts. of cold ether, and rather less of hot ether ; acetic ether, wood-spirit, and acetone 
 also dissolve it readily when hot, and deposit it on cooling. But its best solvent is 
 chloroform, which extracts it even from the aqueous infusion of cantharides. It like- 
 wise dissolves in oils, both fixed and volatile. Its solution in any of the liquids above- 
 mentioned possesses the vesicating power, which, however, is not exhibited by 
 cantharidin in the solid state. A grain of cantharidin mixed with an ounce of lard 
 produces very strong vesication. Cantharidin dissolves in sulphuric acid, and is re- 
 precipitated by water ; also in hot hydrochloric and nitric acids, whence it crystallises 
 on cooling; phosphoric, acetic, and formic acids dissolve but little of it at ordinary tem- 
 peratures. It dissolves in potash-ley, and is precipitated by acetic acid. Ammonia 
 has no action upon it. 
 
 C AWTOKTITE. A variety of sulphide of copper, Cu 2 S, from the Canton mine in 
 Georgia, having hexahedral cleavage, bluish-black colour, and semi-metallic lustre. 
 Specific gravity = 4'18. Hardness = 2'0 (N. A. Pratt, Sill. Am. J. [2] xxiii. 409). 
 Genth (ibid. 417) regards it as a pseudomorph of covellin after galena. 
 
 CANTON'S PHOSPHORUS. A phosphorescent substance prepared by cal- 
 cining for an hour, at a red heat in a crucible, a mixture of 3 pts. of finely ground 
 oyster-shells with 1 pt. of flowers of sulphur. A better phosphorescence is obtained 
 by calcining the entire shell in a closed crucible, after dusting it over with sulphur. 
 Exposure to bright light is necessary to its luminosity in the dark. The magnesia 
 in the shells is said to be essential to the effect. Gypsum mixed with flour becomes 
 phosphorescent when calcined. 
 
 CAOUTCHENE. A hydrocarbon, isomeric with tetrylene, C 4 H 8 , said by Bou- 
 chardat (J. Pharm. Sept. 1837, p. 454), to be produced, together with others, by the 
 dry distillation of caoutchouc (q. v.) It has a density of - 65, boils at 14-5 C., and 
 solidifies in brilliant needles at 10. 
 
 CAOITTCHIN. C 10 H 16 . (Himly, Ann. Ch. Pharm. xxvii. 41; Gr. Williams, 
 Proceedings of the Koyal Society, x. 517; Gm. xiv. 326.) A hydrocarbon contained, 
 together with many other substances, in the oils produced by distillation of caoutchouc 
 and gutta percha. To separate it, rectified oil of caoutchouc boiling between 140 and 
 280 C., is repeatedly shaken up with dilute sulphuric acid, then washed alternately 
 with water and potash-ley, and distilled with water several times. The distillate is 
 dehydrated with chloride of calcium and rectified per se, the portion which distils be- 
 tween 160 and 175, being collected apart ; from this, by repeated rectification and 
 removal of the portions which pass over below 166 and above 174, caoutchin is at 
 length obtained, boiling between 168 and 171; and this product, by repeated frac- 
 tional distillation, may be brought to boil at 171. The purification may also be 
 effected by passing dry hydrochloric acid gas into the cooled oil, previously dried over 
 chloride of calcium, whereby hydrochlorate of caoutchin is produced ; decanting this 
 liquid from the resin, after it has stood for some days ; dissolving it in absolute al- 
 cohol ; precipitating with water ; dehydrating it, and decomposing it by distillation 
 over caustic lime or baryta, and finally over potassium. The product thus obtained 
 is pure caoutchin. (Himly.) 
 
 Caoutchin is a transparent, colourless, mobile liquid, having an odour like that of 
 oil of orange, but not quite so agreeable, and a peculiar aromatic taste. It makes 
 transient grease spots on paper. Specific gravity 0'8423 at C. Boils at 175'5 at 
 075 met. pressure. Does not solidify at 39. Vapour- density 4-461 (Himly), 4-65 
 (Williams), by calculation (2 vols.) = 4*714. It has but little electric conducting 
 power. 
 
CAOUTCHIN. 737 
 
 Caoutchin dissolves in 2000 pts. of water. It likewise takes up a small quantity of 
 water in the cold, and at higher temperatures a larger quantity, which separates on 
 cooling. It dissolves in all proportions of alcohol, ether, and acetate of ethyl ; water 
 separates it from the alcoholic, but not from the ethereal solution, unless alcohol be 
 afterwards added. The alcoholic solution burns with a bright flame, which does not 
 smoke if the caontchin and alcohol have been mixed in the right proportion. It dis- 
 solves slightly in concentrated acetic and formic acids ; also in oils both fixed and 
 volatile, 
 
 Caoutchin absorbs oxygen from the air (45 vols. in fourteen _days), and is converted 
 into a resin, part of it, however, volatilising. It is likewise resinised by various oxidis- 
 ing agents, e. g. by peroxide of hydrogen, nitric oxide, nitrous acid, strong nitric acid, 
 and crystallised chromic acid; it reduces cupric oxide to cuprous oxide and permanganate 
 of potassium to peroxide of manganese, but exerts no deoxidising action, even at the 
 boiling heat, on the oxides of lead, mercuric oxide, or chromate of potassium. It is like- 
 wise unaffected by sodium, potash, baryta, or lime. With potassium it evolves a few 
 gas-bubbles, and covers the metal with a grey film, then remains unaltered. 
 
 Of hydrogen, caoutchin absorbs 2 vols. in three weeks at 20 C. ; of carbonic anhy- 
 dride 11 vols. ; carbonic oxide, marsh-gas, and olefiant-gas are not absorbed by it. Of 
 nitrogen, it absorbs 5 vols. in five weeks ; of nitrous oxide a small quantity ; nitric oxide 
 colours it yellow after a while. It absorbs 3 vols. ammonia-gas, but does not mix with 
 aqueous ammonia. It does not absorb cyanogen gas, but hydrocyanic add and chloride 
 of cyanogen are absorbed by it in any quantity. It dissolves phosphorus and sulphur 
 sparingly in the cold, rather more freely when heated; does not absorb sulphydric acid 
 gas, but mixes in all proportions with sulphide of carbon and xanthic acid. It ab- 
 sorbs hydrochloric, hydrobromic, and hydriodic acid gases, forming the compounds 
 C I9 H 16 .HC1, &c. It easily dissolves the chlorides of sulphur, phosphorus, and carbon, 
 small quantities of iodide of sulphur, and iodide of phosphorus. It dissolves a large 
 quantity of benzole, and a small quantity of oxalic acid ; but not malic, citric, tartrate, 
 tannic, mucie, or succinic acid. 
 
 Caoutchin dropped into strong sulphuric acid, becomes heated, eliminates sulphurous 
 anhydride, and forms a brown unctuous acid, C 10 H l(i S0 3 , which forms soluble barium 
 and calcium-salts, the latter having, according to Williams, the formula C 10 H 15 CaS0 3 . 
 Boiled with strong sclenic acid, it turns brown and gradually decomposes. It is not 
 decomposed by phosphoric or phosphorous acid. 
 
 With chlorine, caoutchin gives off hydrochloric acid and forms chlorocaoutchin, 
 which, after washing with soda-ley, then with water, and dehydration over chloride of 
 calcium, forms a transparent, colourless, neutral, viscid liquid, of specific gravity 1-433, 
 having a strong ethereal odour and extremely sharp burning taste. It dissolves 
 sparingly in water, easily in alcohol and ether, gives off irritating vapours of hydro- 
 chloric acid when distilled per se, and yields a variety of oily products by distillation 
 with alkalis. 
 
 With bromine, caoutchin gives off hydrobromic acid, but remains colourless and 
 transparent ; it easily separates bromine from its solution in water, alcohol, or ether, 
 forming heavy drops of oil. Caoutchin mixed with | vol. water decolorises bromine 
 till 2317 pts. bromine have been added to 100 pts. caoutchin, which is in the ratio 
 of 4 at. bromine to 1 at. caoutchin. 
 
 By the alternate action of bromine and sodium on caoutchin, 2 at. hydrogen are re- 
 moved, andcymene, C 10 H 14 , is produced. (Williams.) 
 
 With iodine, caoutchin turns black, and gives off hydriodic acid. It abstracts 
 iodine from solution in water, alcohol, or ether, forming iodocaoutchin, which is a 
 black-brown oil, giving off hydriodic acid when distilled, easily decomposed by heating 
 with oil of vitriol, bromine, chlorine, fuming nitric acid, or potash, nearly insoluble in 
 water, but soluble in alcohol or ether. Caoutchin distilled with excess of iodine, forms 
 a colourless fragrant oil. 
 
 Hydrochlorate of Caoutchin, C 10 H 16 .HC1. This compound is prepared by passing dry 
 chlorine gas into caoutchin cooled with ice, the delivery-tube terminating a little 
 above the surface of the liquid, washing the product first with soda-ley, then with 
 water, and drying over chloride of calcium. It is also produced, though in an impure 
 state, by treating caoutchin with trichloride of ant! mony or mercuric chloride. It is a 
 transparent, colourless, neutral, viscid liquid, having a strong ethereal odour and a very 
 sharp burning taste. Specific gravity 1-433. It gives off very irritating vapours of 
 hydrochloric acid when distilled ; is decomposed by boiling with sulphuric acid, with 
 elimination of hydrochloric acid ; and yields a variety of oily products by distillation 
 with potash, lime, or baryta. It dissolves sparingly in water, easily in alcohol and 
 ether ; also in hot nitric acid and sulphuric acid, separating out unchanged on cooling; 
 but by long boiling with the latter, it becomes carbonised and gives off hydrochloric 
 acid. 
 
 VOL. I. 3 B 
 
738 CAOUTCHOUC. 
 
 CAOUTCHOUC. Gum elastic, or India Rubber. Gomme ilastique. Federharz. 
 A product of several genera of arboraceous plants, in which it occurs in the form 
 of a milky sap, and exudes from incisions made in their trunks. Among these trees 
 are the Siphonia elastica, S. Cahitchu, Hcvea caoutchouc, H. Guianensis, Jatropha 
 elastica, Ficus elastica, F. indica, F. rdigiosa. Formerly the greater part of the good 
 caoutchouc was imported from Para in South America, but an excellent article has of 
 late years been brought from Assam and other districts of India, in which the trees 
 that yield it greatly abound. The juice drawn from the old trees and in the cold 
 season is preferable to that from the young trees and in the hot season, the quantity 
 being greater the higher the incision is made across and through the bark of the tree. 
 The fluid is of a creamy consistence and colour. Its specific gravity, as imported into 
 this country in well-closed vessels, used to vary from 1-0175 to 1-04125 (Ure); the 
 lighter juice yielded 37 per cent, of solid caoutchouc ; the denser only 20, though it 
 was the thicker of the two. Some samples of juice have a brownish tinge, which pro- 
 ceeds from a little aloetic matter secreted along with it, which, if dried up in it, 
 gives the caoutchouc a certain degree of viscidity, and by its decomposition eventually 
 destroys its firm texture. Such juice ought to be mixed with its own bulk of water 
 and boiled, whereby the aloes are separated and the caoutchouc concretes into a 
 white elastic mass, free from offensive smell. 
 
 Much of the caoutchouc is imported in coarse rough masses. These are cleaned by 
 washing in a trough, with a stream of water, and afterwards kneaded together by the 
 strong pressure of iron-arms in an iron box. The masses thus obtained are next 
 moulded into the forms of square or round cheeses in a press, and finally sliced by 
 knives driven by machinery into thin cakes or ribbands. U. 
 
 Faraday recommends for the purification of caoutchouc, to dilute the natural juice 
 with four times its weight of water, and leave it at rest for twenty-four hours. The 
 caoutchouc then separates and rises to the surface in the form of a cream. This is re- 
 moved, diffused through a fresh quantity of water, and again left to settle at the surface. 
 By repeating this operation till the wash- water is perfectly limpid, the caoutchouc may 
 be obtained very nearly pure. It is then to be spread upon a plate of unglazed earthen- 
 ware to absorb the water, and afterwards pressed. 
 
 Pure caoutchouc is colourless and transparent, but the best found in commerce has 
 a more or less dingy colour from having been dried from the juice in a smoky atmo- 
 sphere. It is a bad conductor of heat, and a non-conductor of electricity. It is very 
 combustible, and burns without residue, emitting a white light. At ordinary tempe- 
 ratures, it is soft, flexible, and highly elastic. Freshly cut surfaces adhere easily and 
 firmly when pressed together, a property which is made available in forming tubes and 
 A^essels out of sheet-caoutchouc. Below C. it becomes hard and rigid. When heated, 
 it gradually softens, and at 120 C. (248 F.) begins to melt; when it is fused, it re- 
 mains greasy and semi-fluid after cooling, but if exposed to the air in thin layers, 
 gradually dries up and recovers its original properties, provided it has not been heated 
 much above its melting point. If, however, it be heated to 200 C. (398 F.) it begins 
 to fume, and is converted into a viscid mass which no longer dries up. If mixed in 
 this state with half its weight of lime slaked to powder, it forms a tenacious non-drying 
 cement, which serves admirably for attaching glass-plates to vessels with ground lips, 
 such as are used for preserving anatomical preparations, as it forms an air-tight, but 
 easily-loosened joint ; if a drying cement be required, a quantity of red lead may be 
 added equal in weight to the lime. 
 
 According to the experiments of Ure (Phil. Trans. 1822), confirmed by those of 
 Faraday (Quart. Journal of Sc. Lit. and Art, xi. 19), caoutchouc is composed wholly 
 of carbon and hydrogen, containing 87*5 per cent, of carbon, and 12-5 hydrogen. It is 
 not, however, a simple proximate principle, but chiefly a mixture of two substances, 
 one much more soluble in ether, benzene, and other liquids than the other. 
 
 On examining with the microscope a thin sheet of caoutchouc, it is seen to be filled 
 with irregularly rounded pores, partly communicating with each other, and dilating 
 under the influence of liquids. It is perfectly insoluble in water and alcohol; but 
 ether, benzene, rock-oil, and sulphide of carbon, penetrate it rapidly, causing it to 
 swell up and apparently dissolving it. 
 
 The liquid thus formed, is not, however, a complete solution, but a mixture formed 
 by the interposition of the dissolved portion between the pores of the insoluble sub- 
 stance, which is considerably swelled up, and has thus become easy to disintegrate. 
 By employing a sufficient quantity of these solvents, renewed from time to time, with- 
 out agitation, so as not to brejik the tumefied portion, the caoutchouc may be com- 
 pletely separated into two parts, viz. a substance perfectly soluble, ductile, and adhering 
 strongly to the surface of bodies to winch it is applied ; and another substance, elastic, 
 tenacious, and sparingly soluble. The proportions of these two principles vary with 
 the quantity of the caoutchouc and the nature of the solvent employed. Anhydrous 
 
CAOUTCHOUC. 739 
 
 ether extracts from amber- coloured caoutchouc 66 per cent, of white soluble matter ; 
 oil of turpentine separates from common caoutchouc 49 per cent, of soluble matter 
 having a yellow colour. 
 
 The best solvent for caoutchouc is a mixture of 6 to 8 pts. of absolute alcohol and 
 100 pts. of sulphide of carbon. ( P a y e n . ) 
 
 Caoutchouc is not altered by dilute acids. Strong sulphuric acid acts slowly, and 
 fuming nitric acid rapidly on it, the latter with complete decomposition. It resists 
 strong alkaline-leys, even at the boiling heat. 
 
 Caoutchouc yields by dry distillation, an empyreumatic oil called oil of caoutchouc 
 or cao utch oucin, which forms an excellent solvent for caoutchouc and other resins. It 
 is a mixture of a considerable number of hydrocarbons. Ordinary impure caoutchouc 
 likewise yields small quantities of carbonic anhydride, carbonic oxide, water, and 
 ammonia. 
 
 Kespecting the nature of the hydrocarbons contained in caoutchouc-oil, different ex- 
 perimenters have arrived at somewhat different results. According to B ouch a r da t 
 (J. Pharm. xxiii. 457), the most volatile of the hydrocarbons has a density of 0'63 at 
 4 C. ; boils at a temperature above C., is not solidified by cold, and is perhaps 
 identical with tetrylene, C 4 H 8 . The next, caoutchene, isomeric with the first, has 
 a density of 0'65, boils at 14'5C., and solidifies at 15 in brilliant needles which 
 melt at 10. 
 
 The less volatile portion of the oil, which does not distil till the temperature is 
 raised to 315 C. and does not solidify at the lowest temperatures, is called h eve en e. 
 It is a clear yellow oil of specific gravity 0'921 at 19C. and belonging to the cam- 
 phene group, C n H'- n . It mixes with alcohol and ether, absorbs chlorine quickly, and 
 solidifies to a waxy mass. By repeated treatment with strong sulphuric acid and 
 potash-ley, it is converted into an oil, boiling at 228 C., having a sweeter and more 
 agreeable taste than heveene, and similar in many respects to eupione. (Bouchardat.) 
 
 Himly (Phil. Mag. [3] Ivi. 579), by subjecting caoutchouc-oil to repeated fractional 
 distillation, obtained : 1. An oil called Faradayin, boiling at 33 C., of specific gravity 
 0'654, and dissolved by strong sulphuric acid without evolution of sulphurous anhydride. 
 According to Liebig, water separates from this solution a colourless oil boiling at 
 220 C. According to Gregory, both this and the more volatile oils belong to the 
 group of camphenes, C n H- n . The oil unites with chlorine and bromine, forming 
 brown liquids. 2. A mixture of oils distilling at 96 C. from which potash extracts 
 creosote, and dilute sulphuric acid separates a brown resin, destroying the odour at the 
 same time. According to Himly, the percentage of carbon in these oils increases as 
 the boiling point rises. 3. Caoutchin (p. 736). 
 
 Another hydrocarbon, isoprene, polymeric with caoutchin, and boiling at 37 
 38 C., has been obtained by Grr. Williams (Proc. Eoy. Soc. x. 56), from the distillation 
 of caoutchouc. From the composition of these several hydrocarbons, it appears that 
 the decomposition of caoutchouc by heat is merely the disruption of a hydrocarbon into 
 other compounds polymeric with it. 
 
 The residue left in the retort, after the volatile oil of caoutchouc has distilled off, 
 forms, when dissolved in the oil, a varnish much used by shipwrights, being impervious 
 to moisture and very elastic. An exceedingly tenacious glue is also made by dissolving 
 1 pt. of caoutchouc, cut up into small pieces, in 4 pts. of coal-tar, adding 2 pts. of 
 shellac when the solution is complete, and heating the whole in an iron vessel. 
 
 VULCANISED CAOUTCHOUC. When caoutchouc is kneaded in an iron box with 
 flowers of sulphur heated to about 112 C. (234 F.), it takes up a certain portion of 
 sulphur, and acquires new properties which greatly increase its utility for various 
 purposes in the arts. It remains perfectly flexible at temperatures below C. and 
 does not soften at 50 C. (122 F.), whereas ordinary caoutchouc becomes perfectly rigid 
 at temperatures several degrees above the freezing point, while a moderate heat ren- 
 ders it so soft and adhesive as to be useless. This sulphured or vulcanised caoutchouc, 
 is an excellent material for tubes for conveying water or gases, or for bags to hold gases 
 under pressure. 
 
 The vulcanisation of caoutchouc requires a temperature of about 150 C. (304 F.), 
 maintained for a few minutes only. A longer contact with sulphur at that temperature 
 causes the caoutchouc to absorb too much, which renders it hard and brittle. Vulca- 
 nised caoutchouc appears to retain only one or two-hundredths of its weight of sulphur 
 in the state of combination ; a larger quantity, 15 or 20 per cent., remains simply 
 interposed between the pores, and may be extracted either by the action of solvents, 
 such as 'ether, benzene, and sulphide of carbon, or by friction, or alternate extension 
 and contraction. If the vulcanised caoutchouc be heated to 120 C., this mechanically 
 interposed sulphur enters into combination with the caoutchouc and renders it brittle. 
 The same combination takes place slowly at ordinary temperatures, so that the caout- 
 chouc after some time, loses its elasticity and becomes brittle. By contact with certain 
 
 3 B 2 
 
740 CAOUTCHOUC CAPILLARITY. 
 
 metals, such" as lead OP silver, the free sulphur in the pores of the caoutchouc is ab- 
 stracted, and thus again the quality is deteriorated. 
 
 The vulcanisation of caoutchouc is effected in various ways : 1. By immersing the 
 sheet-caoutchouc in flowers of sulphur heated to 112 C. till it has absorbed about ~ 
 of its weight, and then heating it for a short time to 150 C., or by immersing the 
 caoutchouc in flowers of sulphur heated to 150, and keeping up that temperature till 
 the sulphuration is complete. 2. By immersing the caoutchouc in a mixture of 100 pts. 
 (sulphide of carbon, and 2-5 protochloride of sulphur, and then plunging it into 
 water to decompose the excess of chloride of sulphur. 3. By immersing articles of 
 caoutchouc already manufactured, in a solution of polysulphide of calcium marking 
 25 Baume, keeping them in it for three hours in a closed vessel at 140 C.. and then 
 washing them with weak alkaline-ley of 60 Bm. This process always yields the 
 right amount of sulphuration. i. By powdering 100 pts. of the caoutchouc in rough 
 laminae, with a mixture of 4 pts. flowers of sulphur and 50 pts. slaked lime, pressing it 
 between rollers so as to incorporate it thoroughly with the powder, then working it 
 into various fabrics by the usual processes, and exposing the finished articles for an 
 hour to the action of vapour of water. By this last treatment, the surface of the 
 caoutchouc experiences a kind of washing, which removes the excess of sulphide of 
 calcium, and brings it to the exact degree of sulphuration required. 
 
 Hardened Caoutchouc. Ebonite. Caoutchouc may be hardened and rendered sus- 
 ceptible of polish by mixing it in the kneading machine or between rollers, with 
 half its weight of sulphur, rolling the mass into sheets, and heating it for two hours 
 to 100 C., and then for four hours to 150. At the latter temperature, the mass may 
 be rolled ; when cold it may be cut like ivory. It serves for the manufacture of 
 combs, knife-handles, buttons, &c. It is also preeminently distinguished by the large 
 quantity of electricity which it evolves when rubbed, and is therefore admirably 
 adapted for the plates of electrical machines. It resists the action of solvents even 
 more obstinately than elastic vulcanised caoutchouc, scarcely even swelling up when 
 immersed in sulphide of carbon. (For a full account of the manufacture and use of 
 caoutchouc, both ordinary and vulcanised, see Ure's Dictionary of Arts, Manufactures 
 and Mines, i. 581604. Muspratfs Chemistry, p. 441451. Payen, Precis de 
 Chimie Industrielle, 4 me ed. i. 139184. Handw. d. Chem. 2 te Aufl. ii. [2] 836853.) 
 
 CAOUTCHOUC, IVEXNERAX.. See ELATEBITE. 
 
 CAOT7TCHOUCXN. Empyreumatie oil of caoutchouc (p. 739). 
 
 CAPERS. See CAPPAEIS. 
 
 C APHOPXCRXTE. Syn. of KHEIN or KHA.BABBARIN. 
 
 C APXXiXiARXTT. The surface of a liquid at rest is horizontal, excepting where 
 it comes in contact with the sides of the vessel ; there it is curved, being concave if the 
 liquid wets the vessel, convex in the contrary case. Moreover, if one end of a narrow 
 tube be dropped into the liquid, the level of the liquid within the tube is not the same 
 as that without, but higher if the liquid wets the vessel and assumes a concave surface, 
 lower if it does not wet the vessel and forms a convex surface ; thus water, alcohol, 
 ether, oils, &c., rise in narrow tubes of glass, metal, or wood, having the inner surface 
 clean ; but if the surface is greased so that the liquid cannot wet it, depression takes 
 place instead of elevation : mercury is also depressed in tubes of glass, but rises in a 
 tin tube, to which it can adhere. The phenomenon is called capillarity (from 
 capilla, a hair), because it is most conspicuous in tubes of very fine bore. The term is, 
 however, extended to all the alterations of level and form of surface which take place 
 at the contact of liquids and solids. The curved surface of the liquid within the 
 tube is called a meniscus. 
 
 The amount of elevation of a liquid in capillary tubes is measured by reading off 
 with the cathetometer (a telescope moving up and down a vertical scale, p. 274), first the 
 height of the lowest point of the meniscus, then the height of a fine metallic point brought 
 exactly in contact with the surface of the liquid. In making this last observation, the 
 point is brought down to the surface of the liquid, till it exactly coincides with its re- 
 flected image therein, and a small quantity of the liquid is then removed with a pipette 
 so as to leave the extremity free. Another mode of observation, adopted chiefly for 
 measuring the depression of mercury in glass tubes, is to place the liquid in a syphon- 
 tube one arm of which is of capillary bore, while the other is wide enough to render 
 the alteration of level due to capillarity imperceptible. The difference of level in the 
 two arms is then read off with the cathetometer. 
 
 By these methods it has been found that the elevation or depression of liquids in 
 capillary tubes is regulated by the following laws : 
 
 1. In a tube of given diameter, the amount of elevation or depression depends upon the 
 nature of the liquid, and not at all upon the nature or the thickness of the material of 
 the tube, the nature of the tube merely determining whether the liquid shall be elevated 
 
CAPNOMOR CAPPERIS SPINOSA. 
 
 741 
 
 <M* depressed, according as the tube is or is not wetted by it, but not affecting the 
 u mount. 
 
 2. The amount of elevation or depression varies with the temperature, but not accord- 
 ing to the same law as the density. Thus Gray-Lussac found that in a tube of 1 milli- 
 metre diameter, the heights to which alcohol rose varied with the temperature and 
 density, as follows : 
 
 Density. Temperature. Height of Column. 
 
 0-8196 8C. 12-18 mm. 
 
 0-8135 16 9-15 
 
 0-8595 10 12-01 
 
 0-9415 8 12-91 
 
 3. In very narrow cylindrical tubes, the amount of elevation or depression of a given 
 liquid varies inversely as the diameter of the tube. 
 
 4. In the annular space enclosed between a wide cylindrical tube, and a solid cylinder 
 which nearly fills it, the height 'to which a liquid rises is half that to which it would 
 rise in a cylindrical tube whose diameter is equal to the thickness of the annular space. 
 Hence also between two parallel flat plates, which may be regarded as cylinders of in- 
 finite radius, the height to which a liquid rises is half that in a cylindrical tube whose 
 diameter is equal to the width between the plates. 
 
 The following table shows the height, as determined by Frankenheim (Pogg. 
 Ann. Ixx. 515), to which different, liquids rise in cylindrical tubes of 1 millimetre radius 
 at 25 C. 
 
 
 Specific 
 Gravity. 
 
 Height 
 in 
 millim. 
 
 
 Specific 
 Gravity. 
 
 Height 
 in 
 millim. 
 
 
 0-840 
 
 6*60 
 
 Water 
 
 0-907 
 
 14-67 
 
 Oil of turpentine 
 Oil of lemon .... 
 Rock-oil 
 
 0871 
 d-8-20 
 0-8^7 
 
 6-33 
 6-63 
 6-52 
 
 Sulphide of carbon . 
 Trichloride of phosphorus 
 Disulphide of chlorine 
 
 1-253 
 1-45 
 
 H587 
 
 4-84 
 3-75 
 4-95 
 
 Oil of cloves .... 
 
 1 -030 
 0'65T 
 
 6-69 
 5'72 
 
 Trichloride of arsenic 
 
 2-18 
 
 4-07 
 2-50 
 
 
 C'800 
 
 5-73 
 
 Chloride of nitrogen 
 
 T34 
 
 3'9 
 
 Fther 
 
 0'7 ' 6 
 
 4-77 
 
 
 3-0 
 
 4-5 
 
 Oxalic ether .... 
 
 1-093 
 
 6-05 
 
 Sulphur .... 
 
 2-14 
 
 5-8 
 
 Acetic ether .... 
 
 0-749 
 
 5-61 
 
 Mercury 
 
 13-59 
 
 -4-6 
 
 For the theory of capillary phenomena, we must refer to works on physics (vid. 
 Miiller, Lehrbiwh der Physik und Mctcorvlogie, 1853, i. 97). 
 
 C AP WOIVIOR. One of the constituents of beech-tar, first separated by R e i c h e n- 
 bach (J. pr. Chem. i. 1). According to Volckel (Ann. Ch. Pharm. Ixxxvi. 99), 
 capnomor is contained, together with creosote and another oil, in the portion of wood- tar 
 which is soluble in potash, and on distilling the alkaline-liquid, capnomor passes over 
 with the vapour of water. It is perhaps partly formed by the decomposition of the 
 creosote. 
 
 It is a colourless oil, having a peculiar odour, rather lighter than water ; boils 
 between 180 and 208 C. Insoluble in pure water and in potash, but dissolves partially 
 when creosote, is likewise present. Contains 81'2 carbon and 7'8 hydrogen; perhaps 
 C 20 H 22 0*. It dissolves in strong sulphuric acid with red-purple colour ; the solution 
 is decolorised by water and then contains a conjugated acid. Nitric acid converts it 
 into prussic and oxalic acid and another crystalline substance. 
 
 C APOH.CIATJITE. A silicate of calcium and aluminium found in several localities 
 in Tuscany, both in radiated laminaa and in crystals belonging to the monoclinic 
 system; cleavage perfectly parallel to OP and ooPoo, easy also parallel to ooP. It 
 has a flesh-red colour with nacreous lustre ; transparent only in thin laminae. Specific 
 gravity 2-470. Hardness = 3*5. It splits easily into thin acicular fragments. It 
 gives off water when heated in a tube ; and melts with intumescence to a white enamel 
 before the blowpipe. Dissolves easily in acids, with separation of gelatinous silica. Ac- 
 cording to Anderson's analysis (N. Edmb. Phil. J. xxxiv. 21), it contains 52*8 SiO 2 
 21-7 A1 4 3 , 0-1 Fe 4 3 , 11-3 Ca 2 0, 1-1 K 2 0, 0'2Na 2 0, 0'4 Mg 2 and 13'1 H 2 ( = 1007)' 
 agreeing nearly with the formula Ca 2 O.Al 4 3 .4Si0 2 + 3 aq. It appears to be a variety 
 of Laumontite formed by weathering. 
 
 CAPPARIS SPIxroSA. A shrub growing in the south of Europe, the root-bark 
 of which is said to contain a neutral bitter principle of sharp irritating taste, and 
 resembling senegin. The flower- buds pickled in salt and vinegar form capers. Dis- 
 tilled with water they yield a distillate having an alliaceous odour. After they have 
 been washed with cold water, hot water extracts from them capric acid and a gelatinous 
 
 3 u 3 
 
742 , CAPRAL CAPRIC ALDEHYDE. 
 
 substance of the pectin group. Capric acid 19 sometimes found deposited on the calicos 
 of the buds in white specks having the appearance of wax. (Kochleder and Bias.) 
 CAPRAIi. A term applied sometimes to caproic, sometimes to capric aldehyde 
 (see those compounds). 
 
 CAPRAIKIDE. Caprinamide. C 10 H 21 NO = N.C 10 H 19 O.H 2 . The primary amide 
 of capric acid, produced by the action of strong ammonia, on an alcoholic solution of 
 caprate of ethyl. When purified by crystallisation from alcohol, it forms colourless 
 shining crystalline scales, which have a silky lustre when dry, are insoluble in water 
 and in aqueous ammonia, but dissolve readily in alcohol. (Ko wney, Ann. Ch. Pharm. 
 Ixxix. 231.) 
 
 CAPRIC ACID. Entic Acid. C 10 H 20 2 . (G-m. xiv. 485.) This acid was first 
 discovered by Chevreul in the butter of cow's milk. It is contained in cocoa-nut oil, 
 and in several kinds of fusel oil ; it occurs among the products of the distillation of 
 oleic acid and of choloidic acid, and is also formed by the oxidation of oleic acid and 
 of oil of rue. 
 
 According to Rowney, it is obtained pure and in tolerable quantity from the residue 
 which remains in the distillation of fusel oil, after the amylic alcohol has distilled off 
 at 132 C. The caproic acid is present as caprate of amyl. When this residue is de- 
 composed by boiling with caustic potash, the amylic alcohol distils over, and the residue 
 contains caprate of potassium. On the addition of hydrochloric acid, capric acid is 
 liberated as an oily mass, which is washed with water and dissolved in dilute am- 
 monia. The caprate of ammonium is mixed with chloride of barium, and the in- 
 soluble barium-salt which precipitates is filtered off, washed with cold, and dissolved in 
 boiling water : on cooling, caprate of barium is deposited almost pure. To obtain the 
 acid, this salt is treated with carbonate of sodium, and the solution of caprate of 
 sodium is filtered from the carbonate of barium, then decomposed with sulphuric acid, 
 which throws down capric acid almost colourless, and in the solid form. It is purified 
 by solution in alcohol and reprecipitation by water. 
 The CAPBATES are mostly difficultly soluble in water. 
 
 Caprate of Barium, C 10 H 19 Ba0 2 , is almost insoluble in cold, but soluble in boil- 
 ing water, from Which it separates in needle-shaped or large prismatic crystals, which 
 float on water if not moistened. 
 
 , Caprate of Calcium, C'^H^CaO 2 , falls as a white insoluble powder when caprate 
 of ammonium is mixed with chloride of calcium. It is more difficultly soluble in boil- 
 ing water than the barium-salt, and crystallises in beautiful lustrous laminae. 
 Caprate of Magnesium resembles the calcium-salt. 
 
 Caprate of Lead Is precipitated as a white amorphous powder when caprate of 
 sodium is mixed with acetate of lead. It is very little soluble in boiling alcohol. 
 
 Caprate of Silver is precipitated on the addition of nitrate of silver to caprate of 
 ammonium. It is but slightly soluble in boiling water, and is deposited on cooling in 
 needle-shaped crystals. When moist, it is readily changed by exposure to light. 
 
 Caprate of Sodium is readily soluble in water and alcohol. On evaporation it is 
 obtained as a horny mass, presenting traces of crystallisation. It is easily soluble in 
 hot absolute alcohol, forming an opalescent mass. 
 
 Caprate of Ethyl. Capric ether, C 10 H 19 (C 2 H 5 )0 2 , is formed by dissolving capric 
 acid in absolute alcohol, saturating the solution with dry hydrochloric acid gas, and 
 then mixing with water. It separates as an oily layer, which, when washed with 
 water, forms a colourless liquid of specific gravity 0'862. E. A. 
 
 CAPRIC ALDEHYDE. C Iir H 20 0. The aldehyde of capric acid has not yet 
 been obtained with certainty. It was formerly supposed, according to the results of 
 Gerhardt (Ann. Ch. Phys. [3] xxiv. 96) and Wagner (J. pr. Chem. xlvi. 155 ; Hi. 48), 
 to be the chief constituent of oil of rue, but according to Gr. Williams (Phil. Trans. 
 1858, p. 199), this oil consists mainly of euodic aldehyde, C"H 22 0. This result, so far 
 as regards the quantitative constitution, has been confirmed by Hallwachs (Ann. Ch. 
 Pharm. cxiii. 107), who, however, maintains that the body C^H^O is not an aldehyde. 
 According to more recent statements by Wagner, on the contrary, oil of rue is really 
 capric aldehyde, and forms with ammonia a compound which, when treated with sul- 
 phydric acid, yields thiocapric aldehyde, C 30 H 6I S 2 N, and with hydrochloric and hydro- 
 cyanic acid a compound homologous with alanine. (See RUE, OIL OF.) (Handw. d. 
 Chem. 2' Aufl. ii. [2] 741.) 
 
 CAPRIHT AMIDE. See CAPRAMIDE. 
 CAPROCIAWITE. Syn. with CAPORCTANITE. 
 CAPRGENE. Syn. with HEXYJ.ENK, C (i H 12 . 
 
CAPROIC ACID. 743 
 
 CAPROIC ACID. C 6 H 18 2 . (Gm. xi. 414.) This acid, the sixth in the series 
 of fatty acids, was first discovered by Chevreul in the butter of cow's milk, in which it 
 exists in combination with glycerin. It exists in considerable quantity in cocoa-nut 
 oil, and in cheese, and is a not unfrequent product of the oxidation of the fatty acids of 
 higher atomic weight; it is also obtained by the oxidation of poppy oil and of casein. 
 . From cocoa-nut oil it is readily obtained by saponification with soda-ley of spe- 
 cific gravity 1-12. The soap is decomposed by sulphuric acid, and rapidly distilled 
 from a copper retort. The distillate, which consists essentially of caproic and caprylio 
 acids, is neutralised with baryta, and the solution evaporated to crystallisation. The 
 crystals which first form are caprylate of barium ; when the solution is further evapo- 
 rated and allowed to stand, caproate of barium is obtained in verrucose crystals. The 
 salt purified by crystallisation and decomposed by a stronger acid, yields caproic acid 
 in an oily form. 
 
 The best method of preparation is that of Frankland of Kolbe, viz. the decomposi- 
 tion of cyanide of amyl by potash : 
 
 CH n N + KHO + H 2 = C 6 H"K0 2 + NH S . 
 
 Cyanide Caproate of Ammonia, 
 
 of amyl. potassium. 
 
 The process as modified by Wurtz, is as follows : To prepare cyanide of amyl, 
 the black mass obtained by calcining ferrocyanide of potassium in a covered cru- 
 cible, is placed in a retort connected with the lower part of a Liebig's condenser, 
 together with four or five times its weight of alcohol, and the mixture is heated to boil- 
 ing. A quantity of iodide of amyl, not quite sufficient to decompose the cyanide, is 
 then gradually introduced through a funnel-tube, and the boiling is continued till the 
 decomposition is complete. This point is ascertained by allowing a drop of the oil 
 which separates on the addition of water, to evaporate on the end of a glass rod held in 
 a flame : the presence of the smallest quantity of iodide is perceptible by the brown 
 vapours of iodine produced. When the conversion of the iodide is effected, the alco- 
 holic liquor is mixed with excess of water, and the oil which separates is boiled with 
 alcoholic solution of potash in a retort connected with the lower end of a Liebig's 
 condenser, until it is completely decomposed into ammonia and caproic acid. The ca- 
 proate of potassium is then decomposed by a stronger acid, and the oily layer removed 
 and distilled. 
 
 Caproic acid is a clear mobile oil of specific gravity 0'931 at 15 C. It has a sudo- 
 rific odour and penetrating acid taste. Sparingly soluble in water, but dissolves 
 completely in absolute alcohol. The acid prepared from cyanide of amyl solidifies at 
 9 C., and boils at 198, and according to Wurtz, has the property of circular pola- 
 risation. That from cocoa-nut oil boils between 202 and 209 (probably owing to an 
 admixture of caprylic acid), and does not affect the plane of polarisation. 
 
 Caproic acid is dissolved by sulphuric acid without change in the cold, and is again 
 liberated on the addition of water. A concentrated solution of caproate of potassium, 
 when subjected to a current from six of Buns en's elements, is electrolysed in a manner 
 analogous to valerate of potassium. The oil which separates on the surface contains 
 amyl, C'H' 22 , together with another body, which is probably caproate of amyl, result- 
 ing from a secondary decomposition : 
 
 2C e H n Z0 2 + = C 10 H 22 -t- K 2 C0 8 + CO 2 . 
 
 Caproate of Amyl. Carbonate 
 
 potassium. of potassium. 
 
 or2CH H K0 2 + O + H 2 = C'H 22 + 2KHC0 3 . 
 
 Caproate of Amyl. Acid carbonate 
 
 potassium. of potassium. 
 
 CAPROATES. The salts of capric acid resemble the valerates, and are obtained in a 
 similar manner. 
 
 Caproate of Ammonium, obtained by saturating caproic acid with ammoniacal 
 gas, is a crystalline salt, which, by absorbing more ammonia, again deliquesces. 
 
 Caproate of Barium is obtained by saturating the acid with carbonate of barium. 
 By spontaneous evaporation of the solution below 18C. it crystallises in lustrous 
 hexagonal laminae, which become milky in the air. Crystallised above 30 C. it forms 
 needles often of some length. It dissolves in 12-5 pts. of water at 20 C. In moist 
 air it smells of caproic acid, and its aqueous solution deposits a basic salt when boiled. 
 When distilled it yields combustible gases, among which propylene, C 3 H 8 , is present 
 in greatest quantity, and an oil passes over which contains propione, C n H* 2 0. The 
 residue consists of carbonate of barium and charcoal. 
 
 Caproate of Calcium forms lustrous square laminse, which are soluble in 49 pts. 
 of water at 14 C., and fuse on being heated, emitting an odour like that of the 
 Labiate. 
 
 3 B 4 
 
744 CAPROIC ALDEHYDE CAPROYL. 
 
 Caproate of Magnesium, C 6 II ll Mg0 2 + aq., crystallises in small aggregated 
 needles, which retain 1 at. of water when heated above 100 C. 
 
 Caproate of Potassium, C 6 H U K0 2 , is obtained by the spontaneous evaporation 
 of its solution, as a transparent jelly, which becomes opaque when warmed. 
 
 Caproate of Silver, C 6 H n Ag0 2 , is obtained by precipitating an aqueous solution 
 of the barium-salt with nitrate of silver, as a white precipitate, sparingly soluble in 
 cold water. After being washed out with cold, and then dissolved in boiling water, it 
 separates on cooling in magnificent crystalline laminae, which are unaltered by light. 
 
 Caproate of Sodium, C 6 H n NaO 2 , resembles the potassium-compound. Its 
 aqueous solution forms a white uncrystalline mass on evaporation. 
 
 Caproate of Strontium, C^'SrO 2 , crystallises in transparent laminae, which 
 effloresce in the air. E. A. 
 
 CAPROIC ALCOHOL. See HEXYLIC ALCOHOL. 
 
 CAPROIC ALDEHYDE. Hydride of Caproyl. C 6 H 12 = C 6 H IJ O.H. This 
 compound appears to be produced in small quantity in the dry distillation of caproate of 
 calcium or barium, being found chiefly in the first portion of the distillate obtained by 
 the rectiiication of crude caprone. (Brazier and Oossleth, Ann. Ch. Pharm. Ixx. 256.) 
 
 CAPROIC ANHYDRIDE or Anhydrous Caproic Acid. C 12 H 22 3 = (C 6 H n O) 2 O. 
 According to Chiozza, this body is prepared by placing 6 at. caproate of barium in 
 a retort, and gradually adding 1 at. oxychloride of phosphorus. The mass becomes 
 warm and pasty; on cooling it is extracted with pure ether; the ethereal solution 
 is agitated with weak potash, then dried over chloride of calcium ; and finally the ether 
 is evaporated in the water-bath. 
 
 Caproic anhydride is a neutral oil, lighter than water, and with an odour resembling 
 caproic acid. When heated it volatilises, emitting an aromatic odour, and leaving a 
 slight carbonaceous residue. E. A. 
 
 CAPIiOIC ETHERS. Caproate of Methyl, C 6 H n (CH 3 )0 2 , is obtained, accord- 
 ing to Fehling, by mixing 2 pts. each of caproic acid and of wood-spirit with 1 pt. of 
 sulphuric acid, and gently heating the mixture. The liquid is mixed with water, and 
 the supernatant oil is washed with water and dried over chloride of calcium. It is 
 a colourless liquid of specific gravity 0-8977 at 18 C. ; boils at 150 C. Its vapour- 
 density is 4 -623. 
 
 Caproate of Ethyl, C 6 H n (C 2 H 5 )0 2 , is obtained like the preceding compound. It is 
 a transparent liquid, with a pine-apple odour, somewhat resembling butyric ether, but 
 not so delicate. Its specific gravity is 0-882 at 18 C., and it boils at 162 C. Its va- 
 pour-density is 4-97. 
 
 Caproate of Amyl. C 6 H u (C 5 H n )0 2 . Crude eaproic acid (prepared by Franklancl 
 and Kolbe's method), the greater part of which passes over at 198 C., contains an ad- 
 mixture of caproate of amyl. On continuing the distillation, it passes over at 212 C. 
 It may also be obtained by neutralising the crude acid with carbonate of potassium, 
 whereupon it remains undissolved as an oily layer. Kemoved, dried over chloride of 
 calcium, and rectified, it is obtained pure, and of constant boiling point at 211 C. It 
 is insoluble in water, but soluble in all proportions in alcohol and ether. It is decom- 
 posed by potash into caproate of potassium and amylic alcohol. E. A, 
 
 CAPRONE. C^'IF-'O ? When caproate of barium is submitted to destructive dis- 
 tillation, tritylene and other gases are given off, and a colourless oil passes over. If 
 this oil be dried and rectified, it begins to boil at 120 C., and the thermometer ulti- 
 mately rises to 160 170 C. By rectification, a product is obtained, boiling con- 
 stantly at 165 C. It is a colourless oil, lighter than and insoluble in water, and having 
 a peculiar odour. It is readily soluble in alcohol and ether, becomes brown in the air, 
 and is attacked by nitric acid even in the cold, nitrovaleric acid, C 5 H 9 (NO-)0 2 , being 
 apparently formed. 
 
 The boiling-point of this compound (164 C.), differs widely from that calculated for 
 caprone, 232, and it is hence doubtful whether it is the true caprone. 
 
 CAPROXBTTRXXiE. C 6 H n K This compound, which contains the elements of 
 caproate of ammonium minus water [C 6 H"(NH 4 )0 2 - 2H 2 0], has not been obtained 
 directly from that salt. The isomeric (or identical) compound, cyanide of amyl, 
 C 5 H n .CN, is obtained by heating an alcoholic solution of iodide of amyl to the 
 boiling point, with excess of cyanide of potassium. (See CYANIDES OF ALCOHOL- 
 RADICLES.) 
 
 CAPRONOYIi. A name applied by Weltzien to the radicle C 6 H n , which may be 
 supposed to exist in eaproic aldehyde, C 6 I1 M .H.O, and in caprone, C 6 H".C 5 H M .0. 
 
 CAPROVZi (or (>'/, ran///, according to Wclf/icn), C c H n O. The radicle of caproic 
 acid audits derivatives : c. <j. caproieaeM = CMr'O.H.O; caproic aldehyde. C*H"O.H ; 
 
CAPRYL CAPRYLIC ALCOHOL. 745 
 
 eaprone, C 6 H n O.C 5 H n , &c. The same term is also sometimes applied to the corre- 
 sponding alcohol -radicle C 6 H ;3 ; but it is much better to designate this radicle by the 
 name Hexyl, as proposed by Gerhardt. (See HEXYL.) 
 
 CAPROYIAIVIINE. See HEXYI.AMIXE. 
 
 CAPROYXiENE. See HEXYLENE. 
 
 CAPRYL or RUTYX,, C'H 19 0. The radicle of capric or rutic acid, 
 OH I9 O.H.O, and its derivatives. The same term is applied to C 8 H I5 0, the radicle 
 of caprylic acid : it is better however to call the latter caprv lyl, unless indeed the 
 term capric acid be altogether abandoned, and rutic acid substituted for it. C'H I9 O 
 would then be called rutyl, and C 8 H I5 0, capryl. There is at present great confusion 
 between the names of these radicles, which is further increased by the application of 
 the same name, capryl, to C 8 H 17 , the radicle of the 8-carbon alcohol. For this last- 
 mentioned radicle we shall use Gerhardt' s name Octyl (q. v.) 
 
 CAPRYLA1VEIUE. See OcTYLAMINE. 
 
 CAPKYIENE. See OCTYLENE. 
 
 C APRYiic ACID. C 8 H 16 2 = C 8 H 15 O.H.O (Gm. xiii. 190). Caprylic acid was 
 discovered by Lerch, in the butter of cow's milk. It is also contained in cocoa-nut oil 
 and in Limburg cheese ; in several kinds of fusel oil it occurs partly free and partly 
 in combination with ethyl and amyl. 
 
 The best source for this acid is cocoa-nut oil : from the difficult solubility of its 
 barium salt, it is easily separated from caproic acid, with which it is associated (see 
 CAPROIC ACID). The caprylate of barium is purified by recrystallisation ; its aqueous 
 solution decomposed by sulphuric acid ; and the oily liquid which rises to the surface 
 is washed and distilled: the distillate between 230 and 238 C. is pure caprylic acid. 
 
 Caprylic acid has a feeble but unpleasant odour, which is more perceptible when 
 the acid is warm. It solidifies at 12 C., melts at 15, and as the liquid slowly cools, 
 laminae resembling cholesterin form in it. At 20, its specific gravity is O'Oll. It 
 boils at 236 238 ; its observed vapour density is 5*31 (calculated 4*98). 
 
 Caprylic acid is monobasic, the general formula of its salts being C 8 H 15 M0 2 . 
 Caprylate of Barium, C 8 H 13 Ba0 2 , crystallises from a hot aqueous solution, in fine, 
 white, fatty laminae ; by spontaneous evaporation, in small white grains. It dissolves 
 in 50 pts. water at 100 C., and in 126 pts. at 10. It is quite insoluble in alcohol and 
 ether. It contains no water of crystallisation, and can be heated to 100 without 
 change. 
 
 Caprylate of Lead, C 8 H 15 Pb0 2 , is obtained on mixing caprylate of barium with 
 nitrate of lead. Is a sparingly soluble precipitate, which melts at 100 C. 
 
 Caprylate of Silver, prepared in the same manner, is white and insoluble. E. A. 
 
 Substitution-derivative of Caprylic Acid. 
 
 NITROCAPRYLIC ACID. C 8 H 15 N0 4 = C 8 H 15 (N0 2 )0 2 (Wirz, Ann. Ch. Fharm. civ. 
 289). This acid is produced by the continued action of nitric acid at the boiling heat on 
 the mixture of non- volatile fatty acids which is obtained from cocoa-nut oil by saponify- 
 ing the oil with soda, decomposing the soap with sulphuric acid, and distilling off the 
 volatile acids. After washing the product with hot water, till the grains of suberic acid 
 mixed with it are removed, there remains a heavy oil, containing nothing but nitroca- 
 prylic and nitrocapric acids. The acid thus obtained is a yellowish-red, syrupy oil, hav- 
 ing a peculiar odour and bitter taste, of specific gravity 1'093, at 18 C. ; it dissolves 
 sparingly in water, more easily in strong nitric acid. When heated, it becomes dark- 
 coloured, and decomposes, with evolution of nitrous acid, and at a higher temperature, 
 detonates slightly. 
 
 Nitrocaprylic acid neutralises alkalis completely. With ammonia, it forms a yel- 
 lowish-red, and with potash a deep red solution, leaving an uncrystallisable mass 
 when evaporated. The ammonia-salt yields with salts of calcium, barium, lead, and 
 copper, flaky precipitates, which form a viscid mass when stirred. The silver-salt, 
 C s H H Ag(NO*)0 2 is precipitated in yellowish- white flakes, which dry up toayellowish- 
 grey mass. 
 
 CAPRYXiXC AXiCOHOXi. See OCTYLIC ALCOHOL. 
 
 CAPRYLIC AX.DEHYDE. Hydride of Caprylyl, C 8 H I6 = C 8 H 15 O.H. A body 
 having this composition and capable of uniting with the acid sulphites of alkali-metals, 
 is obtained, among other products, by the dry distillation of castor-oil soap (ricinoleate 
 of sodium or potassium), either alone or with excess of alkali. It was first obtained 
 by Limpricht (Ann. Ch. Pluirm. xciii. 242), who regards it as caprylic aldehyde; 
 afterwards examined by Bouis (Ann. Ch. Phys. [3] xlviii. 99), who takes the same 
 view of its constitution; and further by Stadcler (J. pr. Chem. Ixxii. 241), and by 
 
746 CAPRYLIC ANHYDRIDE C APR YLIC ETHERS. 
 
 Dachauer (Ann. Ch. Pharm. cvi. 270), who regard it as an acetone, viz. methyl- 
 eenanthyl, CH S .C'H 13 0. According to Bouis, the aldehyde is formed, together with 
 an acid (C'H 18 2 ), and without evolution of gas, chiefly when castor-oil soap is slowly 
 heated to a temperature not exceeding 225 230 C., and without excess of alkali : 
 C 18 H 34 3 = C"H 16 + C'H 18 2 ; 
 
 Ricinoleic Caprylic New acid. 
 
 acid. aldehyde. 
 
 whereas if the soap be quickly and strongly heated, especially with excess of alkali, 
 hydrogen is abundantly evolved, and octylic alcohol is produced, together with sebacic 
 acid (see page 98). Malaguti obtained sometimes octylic alcohol, sometimes caprylic 
 aldehyde, but always sebacic acid ; he explains the formation of these products by the 
 equations : 
 
 C 18 H 34 3 + H 2 + = C 8 H 18 + C 10 H 18 4 
 
 Hicinoleic Octylic Sebacic 
 
 acid. alcohol. acid. 
 
 C I8 H 81 8 + O 2 = C 8 H 16 + C 10 H 18 0* 
 
 Caprylic 
 aldehyde. 
 
 Stiideler and Dachauer likewise obtained sebacic acid in every case (p. 98). 
 
 Caprylic aldehyde is also produced by distilling a mixture of caprylate and formate 
 of calcium (Limpricht): 
 
 To prepare pure caprylic aldehyde, the crude distillate obtained by heating castor- 
 oil soap with excess of hydrate of potassium, is treated with a strong aqueous solution 
 of acid sulphite of sodium ; and the resulting crystalline mass is repeatedly pressed 
 between paper, washed with alcohol, dried over sulphuric acid, and dissolved in hot 
 water, whereby it is decomposed, and caprylic aldehyde set free : it is then dried over 
 chloride of calcium and rectified. According to Bouis, it is better to distil the neutral 
 soap per se, or better still, the barium-salt formed from it, because the latter does not 
 froth. 
 
 Caprylic aldehyde is a colourless, strongly refracting liquid, having an aromatic 
 odour and caustic taste. Specific gravity 0'818 at 19 C. (Bouis). Boiling point 
 17 8 (Limpricht); 171 under ordinary pressure (Bouis). It is insoluble in water. 
 It burns with a bright non-smoking flame ; becomes acid when warm air or oxygen is 
 passed through it (Bouis) ; and is violently oxidised by nitric acid, with formation 
 of caprylic acid and other fatty acids ; chromic acid also partly converts it into an 
 acid. Heated with solid potash, it forms a brown spongy mass. With ammoniacal 
 nitrate of silver it forms a metallic mirror. With pentachloride of phosphorus, it forms 
 chloride of octylene, C 8 H 16 CP. 
 
 Caprylic aldehyde unites with acid sulphites of alkali-metals, without rise of tempe- 
 rature. The compounds are insoluble in excess of the acid sulphite, and are decom- 
 posed by water. The sodium-salt contains 2C 8 H 16 0.2NaS0 3 .S0 2 + 2 aq. 
 
 C APRYI.IC ANHYDRIDE. Anhydrous Caprylic acid, C M H 30 3 . = (C 8 H I5 0) 2 0. 
 This body is obtained by treating 6 at. caprylate of barium with 1 at. of oxychloride 
 of phosphorus. Much heat is disengaged, and the mixture is changed into a pasty 
 mass, developing a peculiar and unpleasant odour, which probably arises from chloride 
 of caprylyl. From this pasty mass, the anhydride is extracted by treatment with 
 ether, which must be free from alcohol. The ethereal solution is agitated with dilute 
 potash-ley, in order to remove caprylic acid, and then dried over chloride of calcium. 
 On the evaporation of the ethereal solution, the anhydride is left as a clear mobile oil, 
 lighter than water. When freshly prepared, it has a sickly odour, which is more 
 evident when it begins to pass into caprylic acid. When heated, it gives off vapours 
 which attack the throat, but have an aromatic odour. In a freezing mixture, it 
 solidifies to a white mass of imperfectly crystalline texture. It begins to boil at 
 280 C., the temperature gradually increasing to 290, when the liquid begins to de- 
 compose. Boiling water does not convert it into caprylic acid, but when left for some 
 time in contact with moist air, it gradually changes into that substance. Potash-ley 
 gradually changes it into caprylic acid. (Chiozza, Ann. Ch. Pharm. Ixxxv. 229). 
 
 E. A. 
 
 CAPRYI.IC ETHERS. Caprylate of Methyl. C 8 H 15 (CH 3 )0 8 , is formed, 
 when caprylic acid dissolved in its own weight of methylic alcohol is mixed with a 
 
 lighly aromatic liquid, 
 wood-spirit. Its specific gravity is O882, and vapour-density 5'48. It is scarcely 
 soluble in water, but dissolves readily in alcohol and in ether. (F e h ling, Ann. Ch, 
 Pharm. liii. 405.) 
 
CAPRYLONE CARAMEL. 747 
 
 Caprylate of Ethyl, C 8 H 15 (C 2 H S )0 2 , is prepared like the preceding compound. 
 It is a colourless liquid, with a pine-apple odour. Its specific gravity is 0-8738 at 15. 
 It boils at 214 C. Vapour-density = 6'!.' It is insoluble in water, but soluble in 
 alcohol and ether. (Feb. ling). E. A. 
 
 C A.PRY J.ONE. This name has been given to a substance which Guckelberger 
 obtained by the destructive distillation of caprylate of barium, in quantities of about 
 half an ounce, with excess of lime. White vapours pass off, and condense in the re- 
 ceiver to a yellow oily liquid, which after some time solidifies to a yellow buttery mass. 
 By appropriate purification, it is obtained as a white crystalline body, like Chinese 
 wax, and of feeble waxy odour. It is very soluble in alcohol and ether, whether hot 
 or cold. It melts at 40 C., and solidifies at 38 to a radiating crystalline mass. It 
 boils at 178, and distils without alteration. 
 
 The boiling-point of caprylone, as calculated from that of its homologue oenanthylone, 
 would be 300 C. The discrepancy between this number and 178, the boiling-point 
 of caprylone, seems to prove that this is not the true acetone. Further experiments 
 are necessary to decide the point. E. A. 
 
 CAPRYILYl. C 8 H I8 0. The radicle of caprylic acid, &c. 
 
 CAPSE3.X.A BURSA PASTORXS. Shepherds Purse. The green parts of 
 this plant contain an acrid sulphuretted volatile oil (oil of mustard?) waxy and fatty 
 matter, saponin, tannin, tartaric, citric, and malic acids, colouring matter, and traces 
 of sugar. 100 pts. of the air-dried herb yielded 9 per cent, of ash containing sand, 
 the composition of which, in 100 pts., after deducting the charcoal, was found to be : 
 15-7 K 2 0, 8-6 Na 2 0, 147 Ca 8 0, 3-1 Mg 2 O, 1-9 Fe 4 :1 , O'l A1 4 3 , 16'2 CO 2 , 6-2 SO 3 , 
 8-4 P 2 5 , 4-2 01, 20-6 SiO 2 and sand. (Daubrawa, Eepert. Pharm. xcix. 127.) 
 
 The seed yields by distillation with water, a volatile oil, which, according to Pless, 
 is identical with oil of mustard. According to Or. J. Mulder, the seed contains in 
 100 pts. : 28'8 fixed oil, 26*5 albumin, 12-3 non-nitrogenous soluble matter, 16*0 woody 
 fibre, 11 -6 water, and 4*8 ash. According to Neuburger, the seed contains 20 per cent, 
 of oil and 23 of albumin. (Handw. d. Chem. 2 te Aufl. ii. [2] 780.) 
 
 CAPSXCXXTE. An alkaloid obtained from Spanish pepper, the fruit of Capsicum 
 annuum. (Braconnot, Ann. Ch. Phys. [2] vi. 1; Witting, Buchner's Eepert. xxxvi. 
 15; Landerer, Vierteljahrs. pr. Pharm. iii. 34.) The same name is applied in 
 America to an oleo-resinous extract from Cayenne pepper (Capsicum baccatum}. 
 
 CAPTJT MORTTirriK. An old term for the residue of a distillation or subli- 
 mation ; thus the impure ferric oxide obtained as a residue in the distillation of fuming 
 sulphuric acid from ferrous sulphate, was called Caput mortuum vitrioli. 
 
 CAR AC-KEEN BXOSS. Irish pearl moss. (Sph&roccus crispus.} An alga, 
 found in abundance on the coasts of the Atlantic and the North Sea. It is used as 
 food, as a remedy in chest complaints, and for the clarification of turbid liquids. It 
 swells up considerably in cold water, and dissolves almost wholly on boiling. The 
 decoction forms, on cooling, a jelly having a faint saline taste, and the peculiar odour 
 of sea-weed. According to Herberger, it contains 79'1 per cent, gelatinous matter, 
 partially soluble in cold water, perfectly in hot water, insoluble in alcohol and ether ; 
 9-5 mucus, insoluble in water, alcohol, and ether; 0*7 resin; 1*3 chloride of sodium; 
 0'7 chloride of magnesium ; 8*7 skeleton, consisting of cellular substance and salts. 
 
 According to Schmidt (Ann. Ch. Pharm. li. 56), the mucus obtained by precipitating 
 the aqueous decoction with alcohol containing hydrochloric acid, pressing the pre- 
 cipitate, and washing it with alcohol, contains 44'8 carbon to 6*2 hydrogen, (whence it 
 appears to be a hydrate of carbon, like sugar, starch, &c.,) and leaves, when burnt, 
 10-39 per cent, ash, chiefly consisting of sulphate of calcium. The skeleton of caragheen 
 moss leaves on incineration an ash containing sulphate and phosphate of calcium, 
 and, according to Sarphati, likewise metallic iodides. (Handw. d. Chem. 2 te Aufl. ii. 
 [2] 782.) 
 
 CARAJURU, CRAJURIT, or CARCURTJ. A red dye-stuff, imported from 
 Para in Brazil, probably identical with chica-red, which is obtained from the leaves of 
 the Ttignonia Chica. Carajuru appears, however, to be superior to ordinary chica, and 
 is perhaps distinguished from it by greater purity. According to Virey (J. Pharm. 
 1844, p. 151) it is a light mealy powder, destitute of taste and smell, and acquiring a 
 coppery lustre by trituration. It is insoluble in water, soluble in alcohol, ether, and 
 alkalis, and precipitated from the latter by acids in its original state. Burns with 
 flame, leaving a considerable quantity of ash. 
 
 CARAIKEXi. (Peligot, Ann. Ch. Phys. Ixvii. 172. Grelis, Ann. Ch. Phys. [3] 
 Hi. 352.) A product of the action of heat upon sugar. When cane-sugar is heated in 
 an oil or metal bath to between 210 and 220 C., care being taken not to exceed the 
 latter temperature, it assumes a brown colour of continually increasing depth, without 
 
748 CARAMEL. 
 
 giving off any permanent gas ; vapour of water is, however, evolved, containing traces 
 of acetic acid and an oily substance. When the tumefaction has ceased, the vessel 
 is found to contain a black substance, which dissolves completely in water : this is 
 caramel. To obtain it pure, it is dissolved in a small quantity of water and precipitated 
 by alcohol. It may also be obtained from glucose, but not so readily. 
 
 Caramel when pure is insipid ; its aqueous solution has a rich sepia tint. It is in- 
 soluble in alcohol ; does not ferment under the influence of yeast ; it yields copious 
 precipitates with ammoniacal acetate of lead and baryta- water. When strongly heated 
 it yields the same products as sugar. (Peligot.) 
 
 Caramel was long regarded as a simple proximate principle of the formula C 12 H 18 9 , 
 the precipitate which it forms with baryta-water having the composition C ia H l7 Ba0 9 . 
 But, according to Gelis, caramel prepared as above is a mixture of several coloured 
 substances, some soluble, others insoluble in water, amongst which he particularly dis- 
 tinguishes three, viz. caramelane, C 12 H 18 9 , caramelene, C^H^O 25 , and carainclin, 
 CH 10 QM^ All these substances are produced from sugar by elimination of the ele- 
 ments of water, the atomic weight being at the same time increased, thus : 
 8C I2 H--O n - 37H 2 = C 96 H 102 51 ; 
 
 Sugar. Caramelin. 
 
 and by keeping sugar for some time at 190 C. these products may be obtained ono 
 after the other. If crystallised cane-sugar be used, the residue, after 10 per cent, has 
 been given off as water, consists of nearly pure caramelane; after 14 or 15 per cent, 
 has gone off, the residue is rich in caramelene; and after a loss of 20 per cent, it 
 consists almost wholly of caramelin. Grape-sugar yields products nearly resembling, 
 but not identical with these. 
 
 Caramelane may also be obtained pure by digesting ordinary caramel with 84 
 per cent, alcohol, which sometimes dissolves it completely, sometimes leaves a residue 
 amounting to 40 per cent ; treating the solution (which contains caramelane, uncle- 
 composed sugar, and sometimes a little caramelene) with yeast to decompose the sugar 
 by fermentation ; evaporating the filtrate to dryness ; redissolving in alcohol, which 
 then leaves the caramelene undissolved ; and evaporating the solution. 
 
 Caramelane, to which ordinary caramel chiefly owes its characteristic properties, is 
 a brown substance, hard and brittle at ordinary temperatures, very soft at 100 C., 
 odourless, with a strong bitter taste, deliquescent, very soluble in water, moderately 
 soluble in aqueous alcohol, sparingly in absolute alcohol, insoluble in ether. It reduces 
 cupric oxide in alkaline solution, also gold and silver from their salts. Nitric acid 
 converts it into oxalic acid. The aqueous solution does not precipitate metallic salts. 
 The alcoholic solution forms, with an alcoholic solution of neutral acetate of lead, a 
 yellow precipitate containing C I2 H 16 Pb 2 9 ; with an ammoniacal solution of acetate of 
 lead, added in sufficient quantity to produce complete precipitation, it yields the 
 compound C 1: H 16 Pb 2 9 .Pb 2 ; and with excess of a solution of baryta in wood-spirit, 
 a precipitate containing C 12 H 16 Ba 2 9 .Ba 2 0. At 190 C. caramelane gives off water and 
 passes into caramelene (G-elis). Volckel (Ann. Ch. Pharm. Ixxxv. 59) applies the 
 term caramelane to the black residue, insoluble in water, left on heating sugar to 
 250 300 C. This residue is insoluble in alcohol, sparingly soluble in potash, and 
 has, according to Volckel, the composition C 24 H 26 13 . It is perhaps identical with the 
 substance here called caramelin. 
 
 Caramelene. C^H^O 25 . The residue left after treating caramel with alcohol of 
 84 per cent, contains caramelene, which may be extracted by cold water, and sepa- 
 rated from the solution by evaporation or by precipitation with absolute alcohol, and 
 freed from a small quantity of admixed caramelin by redissolving it in water. It is 
 solid and brittle, of the colour of mahogany, not hygroscopic, easily soluble in water 
 (exhibiting a colouring power six times as great as that of caramelane) and in dilute 
 alcohol, sparingly in strong alcohol, and insoluble in ether. It reduces cupric oxide 
 from an alkaline solution, and is converted by nitric acid into oxalic acid. Its barium- 
 compound, precipitated by alcohol, is composed of C 36 H 48 Ba 2 25 . With lead it forms 
 the three compounds C 3s H iS Pb 2 25 , C 36 H 48 Pb 2 25 .3Pb 2 0, and C 3ti H 4s Pb ? 25 .5Pb 2 0. 
 
 Caramelin, C 96 H 102 51 , exhibits three isomeric modifications, viz. A, soluble in 
 water ; B, insoluble in water, soluble in other liquids ; C, insoluble in all ordinary 
 solvents. The modifications B and C are contained in the residues left after treating 
 caramel with cold water ; and from these residues B may be extracted by boiling 
 water (J? then passing into A) by 60 per cent, alcohol, or by alkaline liquids. Cara- 
 melin separates from a hot aqueous solution on evaporation in films, by precipitation 
 with alcohol as a copious precipitate, but in both cases as the modification B : similarly 
 when precipitated by acids from alkaline solutions. But when carumelin B is dried, 
 or even left for several days in the moist state, it passes into the modification C, and 
 is then insoluble in all solvents. Caramelin B, which is insoluble in cold water and in 
 
CARANNA - CARBAMIC ACID. 749 
 
 strong alcohol, dissolves in a mixture of those two liquids. Its colouring power is 12 
 times as great as that of caramelane. 
 
 Caramelin is a black, shining, infusible substance. Like caramelane, it reduces gold 
 and silver from their solutions, and cupric oxide in its alkaline solution. Its solution 
 is precipitated by nearly all metallic salts. It forms the compounds C' J6 H 100 Ba 2 51 , 
 C 96 H 100 Ba 2 51 .Ba 2 0, and C*H l *Pb0 M , (Gelis.) 
 
 Maumene (Compt. rend, xxxix. 422) designates by the name caramelin a black- 
 brown compound, C I2 H 8 4 , insoluble in water, acids and alkalis, obtained by mixing Ipt. 
 of sugar with 15 to 30 pts. dichloride of tin, evaporating to dryness, and heating for a 
 few minutes to 120 130 C. ; also by similar treatment of glucose, cellulose, dextrin, 
 and other hydrates of carbon of similar constitution. Volckel's caramelane (p. 748) is 
 probably the same as Gelis's caramelin. 
 
 CARANXT A. A resin obtained from the Bursera gummifera. It is sent into the 
 market in pieces wrapped in leaves ; is grey-black outside, dark brown within ; has a 
 shining fracture ; is brittle and easily powdered. It melts when heated, emitting an 
 aromatic smell. It has a bitterish taste. It resembles resin of guaiac in some respects, 
 and was at one time in repute among the Germans for smoking in pipes, as a remedy 
 in gout. A distilled oil of caranna was also prescribed for a like purpose. It is now 
 disused. 
 
 CARAPA BARK. The bark of a tree indigenous in Guiana and Hispaniola, 
 called Carapa guianensis, Personia guareoides, and Xylocarpus Carapa. It has a 
 bitter taste, like that of cinchona bark, and is used in intermittent fevers. It is said 
 to contain quinic acid, a red colouring matter, and an organic alkaloid called cara- 
 pine, which forms crystalline salts with hydrochloric and acetic acids. (Petroz and 
 K obi net, J. Pharm. vii. 293, 349.) ^ 
 
 The wood of the same tree, which is beautifully veined, is much prized for furniture. 
 
 In the bark of Carapa tulucana, Caventou(J. Pharm. xxxv. 189) found one yellow 
 and two red dyes, and a bitter principle, which he calls tulucumine. 
 
 The root-bark of Carapa molucensis exudes a whitish powder when wounded ; it is 
 bitter and astringent, and is said to be used as a remedy against cholera and biliary 
 
 CARAPA OZXi. A bitter fat oil, obtained by pressure in the heat of the sun 
 from the kernels of Carapa guianensis and C. tulucana. It is used by the Indians 
 for protecting the skin against the punctures of insects. It solidifies at + 4 C. and 
 melts at 10 ; dissolves sparingly in alcohol, easily in ether; is saponified by alkalis. 
 Its bitter taste is said to be due to strychnine, and to be removed by sulphuric acid. 
 The fruits yield by further pressure, assisted by heat, a fat which melts at 40 50 C. 
 (Cadet, J. Pharm. v. 49. Bouillay, ibid. vii. 293.) 
 
 CARAT. An arbitrary weight by which gold and gems are weighed or estimated. 
 The diamond carat is equal to 4 grains whereof 612 are contained in the troy ounce ; in 
 other words, the troy ounce contains 153 diamond carats or 612 diamond-grains. 
 
 In estimating or expressing the fineness of gold, th whole mass is supposed to 
 weigh 24 carats of 12 grs. each, either real or merely proportional, like the assayer's 
 weights; and the pure gold is called fine. Thus, if gold is said to be 23 carats fine, it 
 is to be understood that in a mass weighing 24 carats, the quantity of pure gold is 23 
 carats. U. 
 
 CARBAXKXC ACID. CH 3 N0 2 = NH2 (C<?)" j Q._ This acid is not known in the 
 free state, neither have any of its metallic salts, properly so-called, been obtained. Its ' 
 ammonium-salt, N 2 H 6 CO* = NH ^ < NH 4 ! ' is the S(>calle<i anhydrous carbonate of 
 ammonium, and its compounds with alcohol-radicles constitute the class of bodies 
 called urethanes:c.#. carbamate of ethyl or ethyl-urethane, C 8 H 7 N0 2 = NH ^S21s 0. 
 
 These bodies might also be regarded empirically as compounds of carbonic anhydride 
 with the corresponding alcohol-bases: e.g. ethylurethane as CO 2 + C 2 H 7 N (ethyl- 
 amine) ; but their formation and properties do not accord with this latter view. 
 
 The urethanes are produced, together with sal-ammoniac, by the action of ammonia 
 gas on the chlorocarbonates of the alcohol-radicles : 
 
 C 2 H 5 .C0 2 C1 + 2NH 3 = NH 4 C1 + C-H 5 .CH 2 N0 2 * 
 
 Chlorocar- Ethyl-urethane. 
 
 bonate of 
 ethyl. 
 
 2. By the action of anhydrous ammonia on the corresponding carbonic ethers : 
 
 arbonate Carbamate of Alcohol. 
 
 ethyl. ethyl. 
 
750 CARBAMIC ACID. 
 
 3. By the action of chloride of cyanogen on the alcohols : 
 
 C 2 H 5 .H.O + CN.C1 + H 2 = + HC1 
 
 Carbamic acid in which the whole of the oxygen is replaced by sulphur, constitute* 
 sulphocarbamicacid, CH 3 NS 2 (q.v.) 
 
 There is also an oxysulphocarbamic acid, the ethyl- and amyl-salts of which 
 
 have been obtained, viz. xanthamide, C 2 H 5 v' an< ^ xanthamylamide 
 
 ' Sl ( See those articles J also P a S e 206 -) 
 
 CABBAMATE OF AMMONIUM. Anhydrous Carbonate of Ammonia. N 2 H 6 C0 2 = 
 NH 4 [ ^' ^i 8 sa ^' wn ^ c ^ was discovered by H. Davy, and further investigated 
 by J. Davy and H. Rose, is produced : 1. By passing a mixture of carbonic anhydride 
 and ammonia-gas through a number of glass tubes cooled to a low temperature. In 
 whatever proportion the gases may be mixed, they always unite in the proportion of 
 2 vol. NH 3 to 1 vol. CO 2 . 2. By subliming a mixture of carbonate of sodium and 
 sulphamate of ammonium, N 2 H 6 S0 3 , both perfectly dry. (H. Rose.) 
 
 It is a white mass which smells of ammonia, has a strong alkaline reaction, volatilises 
 a little above 60 C., and condenses again below 60. The specific gravity of its vapour 
 is 0-8992 (H. Rose), 0'90 (Bineau). Now 2 vols. ammonia + 1 voL CO 2 , weigh 
 1-1787 + T5252 = 2-7039, which is nearly three times the observed specific gravity of 
 the vapour. Hence the two gases appear to unite without condensation, although not in 
 equal volumes. Probably the compound exists only in the solid state, and is resolved 
 by heat into CO 2 and 2NH 3 . 
 
 Vapour of sulphuric anhydride converts carbamate of ammonium into sulphamate of 
 ammonium with evolution of carbonic anhydride. Heated in sulphurous anhydride, it 
 yields an orange-coloured sublimate. Hydrochloric acid decomposes it with aid of 
 heat, yielding sal-ammoniac and carbonic anhydride. 
 
 Carbamate of ammonium dissolves readily in water, yielding a solution which gives 
 the reactions of neutral carbonateof ammonium, from which, indeed, it differs only by the 
 elements of water [N 2 H 6 C0 2 = (N 2 H 4 ) 2 C0 3 -H 2 0]. It appears, however to be capable 
 of existing in solution for a short time as carbamate ; for on passing carbonic anhy- 
 dride into aqueous ammonia, taking care that the liquid does not become hot, the 
 resulting solution does not precipitate chloride of calcium or chloride of barium till 
 after some time, unless the liquid be heated. This circumstance is of importance in 
 chemical analysis ; thus, in determining the amount of carbonic acid in a mineral water 
 by means of chloride of calcium and ammonia, it is necessary to leave the liquid to 
 stand for some time, or heat it to the boiling point, in order to insure that the whole 
 of the carbonic acid is precipitated as carbonate of calcium. (Kolbe.) 
 
 According to H. Rose, ordinary carbonate of ammonium prepared by sublimation 
 often contains carbamate. (G*. ii. 430). 
 
 CAEBAMATE OF AMYL. Amyl-urethane, C 6 H 13 N0 2 =CH 2 (C 5 H n )N0 2 . (Medlock, 
 Ann. Ch. Pharm. Ixxi. 104. A. Wurtz, J. Pharm. [3] xx. 22). Obtained by adding 
 ammonia to amylic alcohol saturated with chlorocarbonic oxide, and washing the re- 
 sulting crystalline mass with water to separate sal-ammoniac ; or by passing gaseous 
 chloride of cyanogen into amylic -alcohol and distilling, chloride of amyl then passing 
 over first, and afterwards the carbamate. 
 
 This compound crystallises from boiling water in beautiful silky needles, soluble in 
 alcohol and ether. It melts at 66 C. and distils without alteration at 220. Dis- 
 tilled with caustic baryta, it yields ammonia and amylic alcohol, with a residue of car- 
 bonate of barium. It dissolves completely in cold sulphuric acid, and is precipitated 
 therefrom by water. Heated with sulphuric acid, it forms amyl-sulphuric acid and 
 ammonia, with evolution of carbonic and sulphurous anhydrides. 
 
 CAEBAMATE OF ETHYL. Urethane. C 3 H 7 N0 2 = CH 2 (C 2 H 5 )N0 2 . (Dumas. Ann. Ch. 
 Phys. liv. 233.- Cahours, Compt. rend. xxi. 629. Liebig and Wo'hler, Ann. Ch. 
 Pharm. liv. 370. G-erhardt, Compt. chim. 1846, p. 120. Wurtz, Compt. rend. 
 xxii. 503, J. Pharm. [3] xx. 19) This compound is prepared : 1. By leaving carbonate 
 of ethyl in contact with an equal volume of aqueous ammonia in a corked flask till it 
 completely disappears, and evaporating in a dry vacuum. 2. By treating chlorocar- 
 bonate of ethyl with ammonia, and distilling : the action is very violent. Alcohol of 
 ordinary strength is saturated with gaseous chloride of cyanogen ; the solution is 
 heated for some hours in a sealed long-necked flask placed in a water-bath ; and the 
 liquid when cold is decanted from the deposit of sal-ammoniac arising from a secondary 
 action, and distilled. Chloride of ethyl then passes over first, then alcohol at 80 C. 
 
CARBAMIC ACID. 751 
 
 (p. 749), after which, the temperature rises, and ure thane passes over, condensing in 
 laminse. 
 
 Carbamate of ethyl forms large transparent colourless crystals : even a few drops of 
 its solution left to evaporate are sure to yield these crystals. It melts below 100 C., 
 and distils at about 180 without alteration if dry ; but in the moist state it suffers 
 partial decomposition, giving off torrents of ammonia. It dissolves readily in water, 
 forming a solution which does not precipitate silver-salts ; also in alcohol and ether. 
 Its vapour-density, by experiment, is 3'14, by calculation (2 vols.) = 3'08. 
 
 CARBAMATE OF METHYL. Urtthylane. C 2 H 5 N0 2 = CIF(CH 3 )N0 2 . Obtained like 
 the preceding compounds. Crystallises in long tables derived from an oblique rhom- 
 boidal prism, with very elongated terminal faces. The crystals are not deliquescent, 
 they melt between 52 and 55 C., and solidify at 52 when perfectly dry. Boiling-point 
 1 77 C. Vapour-density, experimental = 2*62 ; by calculation (2 vol.) = 2-60. It is very- 
 soluble in water, less in alcohol, and still less in ether. 100 pts. of water at 11 C. 
 dissolve 217 pts. of it, whereas 100 pts. alcohol at 15 C. dissolve only 73 pts. Dilute 
 sulphuric acid decomposes urethylane into methylic alcohol, acid sulphate of ammonium, 
 and carbonic anhydride : 
 
 Strong sulphuric acid blackens it, eliminating sulphurous anhydride and inflammable 
 gases. Potash decomposes it in the same manner as dilute sulphuric acid. 
 
 CARBAMATE OF TETBYL. C 8 H"N0 2 = CH 2 (C 4 H 9 )N0 2 . Obtained by heating te- 
 trylic alcoholic with liquid chloride of cyanogen, best in a sealed tube, distilling and 
 collecting that which passes over above 220 C. This distillate solidifies on cooling in 
 a crystalline mass, which, when recrystallised from boiling alcohol, forms shining 
 nacreous scales, unctuous to the touch, insoluble in water, soluble in alcohol and 
 ether; they melt at a gentle heat and distil without alteration. (Humann, Ann. Ch. 
 Phys. [3] xliv. 340.) 
 
 Substitution-derivatives of Carbamic Acid. 
 
 ETHYL-CARBAMIC ACID. C 3 H 7 N0 2 = NH (C 2 H 5 )(CO)"| a _ This acidj i somer i c 
 
 with urethane, is not known in the free state ; but its ethylammonium-salt, 
 
 r 2 H 8 N f 0> * s identical with the so-called anhydrous carbonate of (thylamine, 
 
 (C 2 H 7 N) 2 .C0 2 , obtained by passing carbonic anhydride into anhydrous etliylamine 
 cooled by a freezing mixture. It is a snow-white powder, whose aqueous solution, like 
 that of carbamate of ammonium, does not immediately precipitate chloride of barium, 
 unless aided by heat. (Wurtz, Ann. Ch. Phys. [3] xxx. 483.) 
 
 Ethylcarbamate of Ethyl Ethylurethane. C 5 H"N0 2 = C 3 H 6 (C 2 H 5 )N0 2 . 
 Produced by heating cyanate of ethyl with alcohol in a sealed tube : C(C"H 5 ) NO + 
 C 2 H 6 = C 5 H U N0 2 ; sometimes obtained as an accessory product in the preparation 
 of cyanate of ethyl. It is an oily liquid, smelling like carbonate of ethyl. Specific 
 gravity 0-9862. Boiling point 174 175 C. Vapour-density 4'071. Potash decom- 
 poses it, forming alcohol, ethylamine, and carbonate of potassium: C 5 H"N0 2 +, 
 2KHO = C 2 H 6 + C 2 H 7 N + K 2 C0 3 . Heated with strong sulphuric acid, it yields 
 carbonic anhydride, sulphate of ethylamine, and probably also ethylsulphuric acid. 
 (Wurtz, Compt. rend, xxxvii. 182; G-erh. ii. 929; iv. 869.) 
 
 METHYL-CARBAMIC ACID, like the corresponding ethyl-compound, is not known in 
 
 the separate state, but forms a methylammonium-salt, """ ^rtjrex [ 0> which 
 
 may also be regarded as anhydrous carbonate of methylamine, (CH 5 N) 2 .CO- : it is 
 formed by passing carbonic anhydride into dry methylamine, or by distilling a mixture 
 of fused hydrochlorate of methylamine and carbonate of calcium. In the latter case, 
 however, it is mixed with carbonate of methylamine. (Wurtz, Ann. Ch. Phys [31 
 xxx. 450, 461.) 
 
 PHENYL-CARBAMIC ACID. Carbanilic Acid. Anthranilic Acid. C 7 H 7 N0 2 = 
 NH(C 6 H 5 )(CO)"| Q (Fritzgche) Ann Ck pharm xxxix 83 . Liebi& iudm xx^ 
 
 91 ; Gerland, Chem. Soc. Qu. J. v. 133.) This acid, which contains the elements of 
 1 at. carbonic anhydride and 1 at. phenylamine, C 6 H 7 N, and is likewise isomeric with 
 oxybenzamic acid, is obtained by boiling indigo with strong caustic potash, replacing 
 the water as it evaporates, and adding peroxide of manganese before the indigo com- 
 pletely disappears, till the liquid no longer deposits blue indigo on being left at 
 rest. The mass is then dissolved in water and supersaturated with dilute sulphuric 
 
752 CARBAMIDE. 
 
 acid; the filtered liquid is neutralised with potash and evaporated to dryness ; and the 
 residue is digested with alcohol, which dissolves chiefly phony 1-carbama to of potassium, 
 and leaves it in an impure state when evaporated. It is then dissolved in water, acetic 
 acid added, and the yellow or brownish crystals of phenyl-carbamic acid thereby 
 precipitated are purified by animal charcoal and recrystallisation (Fritzsche). 
 According to Chancel this acid is likewise produced by the action of potash on phenyl- 
 carbamide. 
 
 Phenyl-carbamic acid crystallises in transparent, colourless, shining prisms or 
 laminae, often of considerable size. It dissolves very sparingly in cold water, much more 
 in boiling water, very easily in alcohol and ether. Its solutions have an acid reaction. 
 It melts at 132C., and sublimes unaltered. By distillation from coarsely pounded 
 glass, it is resolved into carbonic anhydride and phenylamine. It carbonises when 
 heated with phosphoric anhydride. Strong sulphuric acid converts it into phenyl-sul- 
 phamic acid. When nitrous acid gas is passed into its warm dilute aqueous solution 
 nitrogen is evolved, and the solution yields, when concentrated, crystals of salicylic 
 (phenyl-carbonic acid) : 
 
 HHCOTPXCOyjo + HNO* = 
 
 Phenyl-carbamic acid. Nitrous Phenyl-carbonic 
 
 acid. acid. 
 
 The metallic phenyl-carbamates are but little known. The calcium-salt, C 7 H 6 CaN0 2 , 
 forms rhombohedral crystals, sparingly soluble in cold, moderately in boiling water. The 
 silver-salt, C 7 H 6 AgN0 2 , is deposited in shining laminae on mixing a dilute boiling 
 solution of the calcium-salt with nitrate of silver. The solution of the ammonium-salt 
 likewise precipitates the salts of copper, lead, and zinc. 
 
 Phenyl-carbamates (?) of Ethyl and Methyl. Chancel (Compt. rend. xxx. 751), by 
 treating the nitrobenzoates of ethyl and methyl with sulphydrate of ammonium, ob- 
 tained compound ethers, which he regards as phenyl-carbamates ; but from their 
 mode of formation it is more probable that they are oxybenzamates, which are iso- 
 meric therewith. (See OXYBENZAMIC ACID.) 
 
 CARBAMIDE. CH 4 N 2 = N 2 .(CO)".H 2 .H 2 . This compound is the primary 
 diamide of carbonic acid, and has the same composition as urea, with which indeed it 
 is in all probability identical. It is formed in various ways : 
 
 1. By the action of ammonia on oxychloride of carbon, both being perfectly dry 
 (Regnault, Ann. Ch. Phys. [2] Ixix. 180; Natanson, Ann. Ch.Pharm. xcviii. 287) : 
 
 COC1 2 + 4NH 8 = CH 4 N 2 + 2NH 4 C1. 
 
 The mixture of carbamide and sal-ammoniac thus produced is soluble in water and in 
 aqueous alcohol ; and on adding excess of baryta-water to the solution, evaporating in 
 vacuo, exhausting the residue with absolute alcohol, evaporating to dryness, dissolving 
 in a small quantity of water, treating the solution with nitric acid, and decomposing 
 the resulting nitrate of carbamide with carbonate of barium, the carbamide is obtained 
 in the separate state (Natanson). 2. By the action of ammonia on carbonate of 
 ethyl. When the two substances are heated together in a sealed tube to 180 C., 
 carbamate of ethyl is first formed (at 100), and afterwards converted by the excess 
 of ammonia into carbamide : 
 
 (CO)"(C 2 H 5 ) 2 2 + NH 3 = C 2 H 5 .H.O + 
 
 C2H5 - H - + N 2 (CO)".H 4 . 
 
 3. By the action of heat on the isomeric compound, cyanate of ammonium, NH 4 .CNO, 
 or even when a solution of that salt is left to evaporate spontaneously, also when 
 cyanate of potassium is mixed with sulphate of ammonium, the mixture left to evapo- 
 rate, and the residue exhausted with alcohol. 4. By decomposing ammonio-cupric 
 fulminate with sulphydric acid (see FULMINIC ACID). 5. In the decomposition of ox- 
 amide (q. v.} at a red heat. 6. By the oxidation of uric acid. 
 
 The product obtained by the last four processes is nrea; the same substance occurs 
 as an animal excretion in the urine, in which indeed it was first discovered, being 
 produced by the oxidation of the nitrogenous tissues. Whether the carbamide pro- 
 duced by the action of ammonia on carbonic ether or on oxychloride of carbon is 
 identical with this, or only isomeric, is a point perhaps not absolutely decided. Never- 
 theless it agrees with urea in its most essential characters, viz. in forming a sparingly 
 soluble crystalline salt with nitric acid, and in being resolved by the action of tho 
 stronger acids into ammonia and carbonic anhydride, as represented by the equation: 
 CH 4 N 2 + H 2 = 2NH 3 + CO 2 . 
 

 CARBAMIDE. 753 
 
 It is true that Regnault did not obtain a crystalline salt by adding nitric acid to the 
 mixture of carbamide and sal-ammoniac produced by the first process ; perhaps in con- 
 sequence of the presence of the sal-ammoniac. Natanson, however, did obtain a crys- 
 talline nitrate in the manner above described. No decided difference has, indeed, been 
 pointed out between carbamide and urea. "We shall, however, refer to the article 
 UBEA for the preparation and properties of the substance usually so called, and shall 
 here describe a number of substitution-products, commonly called compound ureas. 
 
 Substitution-products of Carbamide : Compound Ureas. 
 
 The hydrogen in carbamide may be more or less replaced by organic radicles, acid or 
 basic. The compounds containing 1 at. of an alcohol-radicle, are obtained chiefly by the 
 action of ammonia on the cyanates of those radicles, just as carbamide or urea itself is 
 produced by the action of ammonia on cyanic acid (cyanate of hydrogen.) 
 
 HCNO + NH 3 = CH<N 2 0. 
 
 Cyanic Carbamide. 
 
 Acid. 
 
 C 2 H 5 .CNO + NH S = CH S (C 2 H 4 )N 2 0. 
 
 Cyanate of Ethyl-carbamide. 
 
 Ethyl. 
 
 Those which contain 2 at. of an alcohol-radicle are produced in like manner by the 
 action of an amine-base on the cyanate of an alcohol-radicle, e.g. ethyl-allylcarbamide, 
 by the action of ethylamine on cyanate of allyl. All these carbamides containing basic 
 radicles form crystalline-salts with nitric acid, and are resolved by the action of sulphuric 
 or hydrochloric acid, or of alkalis, into carbonic anhydride and an amine base, just as 
 carbamide is resolved under similar circumstances into carbonic anhydride and ammonia. 
 
 The carbamides containing acid radicles are produced by the action of the chlorides 
 of those radicles on urea. They do not form salts with nitric acid. "When heated they 
 are resolved into cyanuric acid and the corresponding acid amide (vide infra). 
 
 a. Carbamidcscx Ureas containing Acidradicles. (Zinin, Ann. Ch. Pharm. 
 xcii. 403. Moldenhauer, ibid. xciv. 100.) 
 
 ( (CO)" 
 ACETYL-CABB AMIDE. C 2 H 6 N 2 2 = N 2 K C 2 H 3 0. Crystallises from boiling alcohol 
 
 ( H 3 
 
 in long silky needles, and from boiling water, in stars or tufts of rhomboi'dal prisms 
 Dissolves in 100 pts. of cold and 10 pts. of boiling alcohol ; much more soluble in 
 water, insoluble in ether. At 160 C. it yields a slight woolly sublimate ; melts at 
 200 (Zinin), at 112 (Moldenhauer), and at a higher temperature is resolved into 
 cyanuric acid and acetamide : 
 
 3C 8 HN 2 2 = C 8 H 3 N 3 3 + 3(N.H 2 .C 2 H 3 0). 
 
 It is not precipitated by nitric acid or by mercuric nitrate. 
 
 BENZOYL-CABBAMIDE. C S H 8 N 2 2 = N 2 .(CO)".C 7 H 5 O.H 3 . Obtained by heating 
 powdered urea with chloride of benzoyl to 150 155 C. As soon as all the urea is 
 melted upon the chloride, the mixture must be removed from the bath and briskly 
 stirred, whereupon it becomes pasty. The product washed with cold alcohol yields 
 benzoyl-carbamide as a crystalline powder. It crystallises from boiling alcohol in 
 thin elongated rectangular laminae, often united in groups. It is much less soluble in 
 water and in ether than in cold alcohol ; strong boiling hydrochloric acid dissolves it 
 better than pure water. Heated on platinum-foil it melts, emitting the odour of 
 cyanide of phenyl (benzonitrile), afterwards that of cyanic acid, and finally volatilises 
 altogether. Heated to 200 O. in a tube, it melts to a colourless liquid, which at a 
 higher temperature, is resolved into cyanuric acid and benzamide. Ammonia has no 
 action on benzoyl-carbamide. Potash dissolves it readily, and acids separate it from 
 the solution. The alkaline solution, when boiled, gives off ammonia, and forms carbo- 
 nate and benzoate of the alkali-metal. 
 
 BUTYBYL-CARBAMIDE, C S H 10 N 2 2 = N 2 . (CO )". C 4 H 7 O.H 3 . Cry stallises readily from 
 water in small scales, from alcohol in thin elongated rhombic laminae. It is tasteless 
 and inodorous. Melts at 176 C. to a yellowish liquid which solidifies in a crystalline 
 mass on cooling. A high temperature decomposes it like acetyl-urea. It. aqueous 
 solution is not precipitated by nitric acid, oxalic acid, or mercuric nitrate. 
 
 VALEBYL-C ABB AMIDE, C 8 H 12 N 2 2 = N 2 (CO)".C 5 H 9 O.H 3 , crystallises from boiling 
 water in small nacreous crystals, unctuous to the touch ; from alcohol in needles. It is 
 nearly insoluble in cold water, melts at 91C. and when carefully heated yields a sub- 
 limate of large iridescent scales. 
 
 VOL. I. 3 C 
 
754 CARBAMIDE. 
 
 J8. Carl amides Off Ureas containing Basylous radicles: 
 
 ALLYL-CARBAMIDE, C 4 H 8 N 2 = N 2 .(CO)".C 3 H 5 .H 3 . (Cahours andHofmann, 
 Phil. Trans. 1855, p. 555.) Obtained by the action of ammonia on cyanate of allyl, 
 (C 8 H 5 .CNO + NH 8 = C*H"N-0.) Crystallises easily by evaporation both from water 
 and from alcohol. Its composition is that of thiosinamine in which the sulphur is re- 
 placed by oxygen. 
 
 ALLYL-SULPHOCARBAMIDE, N 2 .(CS)".C 3 H 5 .JF, also called thiosinamine, is produced 
 by the action of ammonia on oil of mustard. Ethyl-, phenyl-, and naphthyl-derivatives 
 of it are produced by treating oil of mustard with ethylamine, phenylamine and naph- 
 thylamine. 
 
 DIALLYL-CARBAMIDB. Sinapolinc. C 7 H 12 N 2 = N 2 .(CO)".(C 3 H S ) 2 .H 2 . Produced : 
 
 1. By the action of oxide of lead and water on sulphocyanate of allyl (oil of mustard) : 
 
 2(C 8 H 5 .CNS) + 3Pb 2 + H 2 = C 7 H 12 N 2 + Pb 2 CO 3 + 2Pb 2 S. 
 
 2. By heating cyanate of allyl with water or with aqueous potash : 
 
 2(C 3 H 5 .CNO) + H 2 = C 7 H 12 N 2 + CO 2 . 
 
 If potash is used, care must be taken that the action does not go too far ; otherwise 
 nothing but amine-bases will be formed (Cahours and Hofmann. loc. cit.) For the 
 properties and reactions of this compound, see SINAPOLINE. 
 
 AMYL-CARBAMIDE. C 6 H I4 N 2 O = N 2 .(CO)".C 5 H".H 3 . (A. Wurtz, Compt. rend. 
 xxxii. 417 ). Produced by the action of ammonia on cyanate of amyl. It is decomposed 
 by potash into amylamine and carbonate of potassium. It forms a crystalline nitrate. 
 
 BENZYL-CARBAMIDE. Toluyl-urea. C 8 H-N 2 = N 2 .(CO)".C 7 H 7 .H 3 . This sub- 
 stance, or more probably an isomer thereof, is produced by the action of sulphydrate of 
 ammonium on nitrotoluamide. (No ad, Phil. Mag. [4] vii. 142. (See TOLUAMIDE.) 
 
 ETHYL-CARBAMIDE, C 3 H 8 N 2 0=N 2 .(CO)''.C 2 H 5 .H 3 . (Wurtz, Compt. rend, xxxii. 
 414.) Produced by the action of ammonia on cyanate of ethyl. Dissolves readily in 
 water and alcohol, and crystallises from alcohol in large prisms which decompose at 
 200 C., with evolution of ammonia and other products. The aqueous solution is decom- 
 posed by chlorine, forming a heavy liquid which crystallises gradually. Nitric acid 
 does not form a precipitate in the aqueous solution, but crystals of nitrate of ethyl- 
 carbamide are obtained on evaporation. 
 
 DIETHYL-CARBAMIDE, C 5 H 12 N 2 O = N 2 .(CO)".(C 2 H 5 ) 2 .H 2 . Produced, like the allyl- 
 compound, by the action of water on cyanate of ethyl ; also by the action of ethylamine 
 on cyanate of ethyl: C 2 H 5 .CNO + C 2 H 7 N = C 5 H I2 N 2 0. The nitrate forms very acid 
 deliquescent rhombic prisms containing C 5 H 12 N 2 O.HN0 3 . (Wurtz.) 
 
 ETHYL-AIXYL-CARBAMIDE, C 6 H 12 N 2 = N 2 .(CO)".C 2 H 5 .C 3 H S .H 2 . (Cahours and 
 Hofmann, loc. cit.) By the action of ethylamine on cyanide of allyl. Crystallises in 
 beautiful prisms. 
 
 Similar^ compounds are formed by the action of methylamine, amylamine, and 
 phenylamine on cyanate of allyl. 
 
 ETHYL-ALLYL-SULPHOCARBAMIDE, N 2 (CS)".C 2 H 5 .C 3 H 5 .H 3 . Syn. of ETHYLTHIOSINA- 
 MINE. (See THIOSINAMINE.) 
 
 ETHYL-AMYL-CARBAMIDE, C S H 18 N 2 = N 2 (CO)".C 2 H 5 .C 5 H n .H 2 . Action of amy- 
 lamine on cyanate of ethyl. (Wurtz.) 
 
 METHYL-CARBAMIDE, C a H a N 2 = N 2 .(CO)".CH 3 .H 3 . (Wurtz, loc. cit.) Ob- 
 tained by the action of ammonia on cyanate of methyl ; also by evaporating a mixture 
 of sulphate of methylamine and cyanate of potassium and extracting the residue with 
 alcohol. Crystallises in long transparent deliquescent prisms. The aqueous solution 
 is neutral to test-paper, and if somewhat concentrated yields with nitric acid a preci- 
 pitate of C 2 H 6 N 8 O.HNO S . 
 
 DIMETHYL-CARBAMIDE, C 3 H 8 N 2 = N 2 .(CO)".(CH 3 ) 2 .H 2 . (Wurtz, loc. cit.) Isomeric 
 with ethyl-carbamide. Produced by the action of water, or of methylamine on cyanate 
 of methyl. Crystallises easily ; melts at 97 C. ; is permanent in the air ; vola- 
 tilises without alteration ; dissolves readily in water and alcohol ; combines with 
 nitric acid, forming the salt C 3 H 8 N 2 O.HN0 3 . 
 
 METHYL-ETHYL-CARBAMIDE C 4 H 10 N 2 = N 2 .(CO)".CH 3 .C 2 H 5 .H 2 . Very deliquescent 
 substance, obtained by the action of methylamine on cyanate of ethyl. (Wurtz.) 
 
 NAPHTHYL-CARBAMIDE, C 11 H :o N 2 = N 2 (CO").C 10 H 7 .H 3 . (H.Schiff, Chem. Gaz. 
 1857, p. 211.) -Obtained by saturating a solution of naphthylamine in anhydrous 
 ether with cyanic acid gas, and recrystaliising from hot alcohol. Flat, shining, flexible 
 needles, nearly insoluble in wuter, more soluble in alcohol, easily soluble in ether : the 
 latter solution yields a crystalline precipitate with oxalic acid. Naphthyl-carbaniide 
 yields by spontaneous decomposition, a resinous substance, whose alcoholic solution is 
 
CARBAMIDE. 755 
 
 coloured violet by acids, and red again by alkalis. The same reaction has been ob- 
 served to be produced on test-paper by a tincture of madder (Sacc), and by nitroso- 
 naphthalin (Church and Perk in, Jahresber. d. Chem. 1856, p. 609). 
 
 NAPHTHYL-AIXYL-SULPHOCARBAMIDE. N 2 (CS").C 10 H 7 .C S H 5 .H 2 . Syn. of NAPHTHYI.- 
 THIOSINAMINE. (See THIOSINAMINE.) 
 
 PHENYL-CARBAMIDE, C 7 H 8 N 2 = N 2 .(CO)".C 6 H 5 .H 3 . Phenyl-urea, Aniline-urea, 
 Carbanilamide, Carbarmde-carbanilide. (A. W. Hofmann, Ann. Ch. Pharm. liii. 57 ; 
 Ivii. 265; Ixx. 130; Ixxiv. 14; Gm. xi. 503.) This compound is obtained: 1. By 
 passing cyanic acid vapour into anhydrous phenylamine, kept as cool as possible ; dis- 
 solving the resulting crystalline mass in not water; filtering to separate dipheuyl- 
 carbamide (which is produced more abundantly in proportion as the phenylamine has 
 been more heated) ; and cooling the filtrate to the crystallising point. 2. By 
 treating sulphate or hydrochlorate of phenylamine with aqueous cyanate of potassium, 
 and separating the resulting phenyl-carbamide (cyanate of phenylamine) by diges- 
 tion in alcohol. 3. By mixing phenylamine with an aqueous solution of chloride of 
 cyanogen (obtained by passing chlorine gas through aqueous hydrocyanic acid), puri- 
 fying the resulting crystals with animal charcoal, and recrystallising from hot water. 
 4. Cyanate of phenyl mixed with ammonia, immediately solidifies in the form of 
 phenyl-carbamide, C P H 5 .CNO + NH 3 = C 7 H 8 N 2 0. 
 
 Phenyl-carbamide forms fusible needles and laminae, sparingly soluble in cold, easily 
 in boiling water, easily also in alcohol and ether. It dissolves in nitric acid, but scarcely 
 to a greater amount than in water, and crystallises therefrom unaltered, differing in 
 this respect from carbamide. It dissolves also without alteration in cold sulphuric 
 acid, but when heated therewith, it is resolved into carbonic anhydride,, phenyl-sulph- 
 amic acid, and acid sulphate of ammonium : 
 
 C'H 8 N 2 + 2H 2 SO< = CO 2 + N.H.CH 5 .(S0 2 )' 
 
 Heated above its melting-point, it is resolved into ammonia, diphenyl-carbamide, and 
 cyanuric acid : 
 
 6[N 2 .(CO)".C 6 H 5 .H S ] = 3NH 3 + 3[N 2 .(CO)".(C fi H 5 ) 2 .H 2 ] + N 3 .H 3 .(CC>) 3 
 
 Phenyl-carbamide. Diphenyl-carbamide. Cyanuric acid. 
 
 By boiling with strong potash-ley, or more quickly by fusion with hydrate of potassium, 
 it yields ammonia, phenylamine, and carbonate of potassium : 
 
 C 7 H 8 N 2 + 2KHO = NH 3 + C 6 H 7 N + K 2 C0 3 . 
 It is not decomposed by boiling with dilute acids or alkalis. 
 
 The name phcnyl-urea has hitherto been generally applied to the isomeric compound, 
 which Chancel obtained by the action of sulphydrate of ammonium on nitrobenzamide 
 (Grerh. Traite, i. 427). This compound is a powerful base ; but it does not agree with 
 the ureas, either in its mode of formation, or in its reaction with alkalis. It should 
 rather be regarded as oxybenzodiamide (q. #.) the primary diamide of oxybenzoic acid 
 (C 7 H 6 3 ). Its formation may be represented by the equation : 
 
 . w <C 7 H<0)" 
 
 Oxy 
 
 itrobenzamide. Oxybenzo- 
 
 diamide. 
 
 When treated with potash,- it yields ammonia, and an acid which is probably oxyben- 
 zoic acid. The reaction consists of two stages, ammonia and oxybenzamic acid being 
 formed in the first, ammonia and oxybenzoic acid in the second : 
 
 H'O = 
 
 Oxybenzo- Oxybenzamic 
 
 diamide. acid. 
 
 N.H*.(C'H'0)"jo + 
 
 Oxybenzamic Oxybenzoic 
 
 acid. acid.* 
 
 The true phenyl-urea is the compound above described as phenyl-carbamide. 
 
 ETHYI^-PHENYL-CAEBAMIDE, C 9 H 12 N 2 = N 2 .(CO)".C 2 H 5 .C 6 H 5 .H 2 , is obtained by dis- 
 solving phenylamine in cyanate of ethyl. Great heat is evolved, and the mixture 
 on cooling solidifies to a crystalline mass. It is slowly decomposed by potash, yield- 
 ing phenylamine, ethylamine, and carbonic anhydride. (Wurtz. Compt. rend, xxxii. 
 417.) 
 
 * See a paper by Dr. Hofmann (Proc. Roy. Soc. x. 602), where however the acid formed is said to 
 be not oxybenzoic, but benzok acid. 
 
 3 C 2 
 
756 CARBAMIDE. 
 
 NITBOPHENYL-CABBAMIDB, C 7 H 7 N 3 = N 2 .(CO)".C 8 H 4 (N0 2 ).H S . Produced, toge- 
 ther with dinitromelaniline, by the action of gaseous chloride of cyanogen on nitro- 
 phenylamine dissolved in ether. (Hofmann, Ann. Ch. Pharm. Ixvii. 156 ; Ixx. 137.) 
 
 DIPHENYL-CABBAMIDE. Diphenyl-urea, Carbanilide, Carbophenylamide. C I3 H 12 N 8 = 
 N 2 .(CO)".(C 6 H 5 ) 2 .H 2 (Hofmann, Ann. Ch. Pharm. Ivii. 266; Gm. xi. 349). Pro- 
 duced : 1. By the action of cyanate of phenyl on phenylamine, or on water : 
 
 2[N.(CO)".C 6 H 5 ] + H 2 = CO 2 + N 2 .(CO)".(C 6 H 5 ) 2 .H 2 . 
 
 2. By the action of phenylamine on oxychloride of carbon. 3. In the decomposition 
 of diphenyl-sulphocarbamide by potash. 4. By the dry distillation of phenyl-car- 
 bamide, melanoximide, or oxalate of melaniline. (See those compounds.) 
 
 Diphenyl-carbamide forms white silky needles, which melt at 205 C. and distil 
 without decomposition. It is odourless at ordinary temperatures, but has a suffocating 
 odour when heated. It dissolves sparingly in water, abundantly in alcohol and ether. 
 
 "When quickly heated in the moist state, it yields carbonate of phenylamine, together 
 with other products. With strong sulphuric acid, it gives off carbonic anhydride, and 
 forms water and phenylsulphamic acid : 
 
 jo*\ 
 
 (coy.o + H*O 
 
 By boiling with potash, it is resolved into phenylamine and carbonate of potassium. 
 
 Diphenyl-carbamide is isomeric with flavine, an organic base produced by the action 
 of reducing agents on dinitrobenzophenone. This base is indeed sometimes regarded 
 as diphenyl-urea (Gerh. i. 430); but it does not exhibit the characters of a urea. 
 (See FLAVINE.) 
 
 PHENYLSULPHOCARBAMIDE, C 7 H 8 N 2 S = N 2 (CS)".C 6 H 5 .H 3 . (H of man ^Proceed- 
 ings of the Eoyal Society, ix. 276.) Produced by the action of alcoholic ammonia on sul- 
 phocyanate of phenyl : 
 
 C 6 H 5 .CNS + NH 3 = C 7 H 8 N 2 S. 
 
 The mixture, on being gently warmed, quickly solidifies into a crystalline compound, 
 which may be obtained in beautiful needles by crystallisation from boiling water. 
 
 Phenylsulphocarbamide is a weak base, and forms a chloroplatinate containing 
 C 7 H 8 N 2 S.HCl.PtCl 2 . It also combines with nitrate of silver. By boiling with nitrate 
 df silver, it is converted into phenyl-carbamide. 
 
 PHENYL-AIXYL-SULPHOCARBAMIDE. N 2 .(CS)".C 6 H S .C 3 H 5 .H 2 . Syn. with PHENYL- 
 
 TH1OSINAMINE. (See THIOSINAMINE.) 
 
 DIPHENYL-SULPHOCABBAMIDE. Sulphocttrbanilide, Sulphophenyl-urca. C 13 H 12 N 2 S = 
 N 2 (CS)".(C 6 H 5 ) 2 .H 2 . (Hofmann, Ann. Ch. Pharm. Ivii. 266 ; Ixx. 144 ; Gm. xi. 350. 
 Further, Proc. Koy. Soc.x. 274. Laurent and Delbos, J. Pharm. [3] x. 309. 
 Laurent and Gerhardt, Ann. Ch.Phys. [3] xxii. 103 ; xxiv. 196.) This compound 
 is obtained: 1. By the action of sulphide of carbon on phenylamine, the action being 
 accelerated by addition of alcohol (Hofmann) : 
 
 2CH 7 N + CS 2 = C' 3 H 12 N-S + H'S. 
 
 2. By heating a mixture of phenylamine, sulphocyanate of potassium, and sulphuric 
 acid, the diphenyl-sulphocarbamide then distilling over, while sulphate of ammonium 
 remains behind (Laurent and Gerhardt). 3. By mixing phenylamine with sulpho- 
 cyanate of phenyl: C d H 5 .CNS + C 6 H 7 N = C 13 H 12 N-S. (Hofmann.) 
 
 Diphenyl-sulphocarbamide separates from the mixture of phenylamine and sulphide 
 of carbon, in crystalline scales or rhombic tables ; from alcohol, in brilliant iridescent 
 laminae. It dissolves sparingly in water, easily in alcohol. It has a peculiar odour, 
 especially when heated, and a bitter taste exceeding in intensity that of any other 
 known substance. It melts at 140 C., and distils without decomposition. Heated 
 with strong sulphuric acid, it forms phenyl-sulphamic acid, giving off carbonic anhydride 
 and sulphydric acid (Hofmann): 
 
 C 13 H 12 N 2 S + 2H 2 S0 4 = CO 2 + H 2 S + !* , 
 
 V H 
 
 By phosphoric anhydride, chloride of zinc, or hydrochloric acid gas, it is resolved 
 into phenylamine and sulphocyanate of phenyl (Hofmann). Fused with potash, it 
 yields phenylamine, together with sulphydrate and carbonate of potassium : 
 
 C 13 H I2 N 2 S + 3KHO - 2C 6 H 7 N + K 2 C0 3 + KES. 
 
 When boiled with alcoholic potash, it is converted into diphenyl-carbamide : 
 C 1S H 12 N*S + K 2 == K 2 S + C 18 H 12 N 2 O. 
 
CABANIL CARBON. 757 
 
 Similarly when its alcoholic solution is boiled with mercuric oxide. It is not decom- 
 posed by dilute acids or alkalis. 
 
 PJPERYL-CARB AMIDE. Piperyl-urea^peridine-urea. C 6 H 12 N 2 =N 8 (CO)". C 5 H 9 .H 3 
 (Cahours, Ann. Ch. Phys. [3] xxxviii. 76.) Obtained by boiling sulphate of pipe- 
 ridine with cyanate of potassium, evaporating to dryness, and exhausting with strong 
 alcohol. It appears also to be formed when vapour of cyanic acid or moist chloride of 
 cyanogen is passed into piperidine. The alcoholic solution yields it, by spontaneous 
 evaporation, in long white needles. 
 
 Methyl-pipcryl-carbamide, C 6 H n (CH 3 )N 2 0, and Ethyl-piperyl-carbamide, 
 C 6 H"(C 2 H)N 2 b, are produced by the action of piperidine on the cyanates of methyl 
 and ethyl. 
 
 CARBANXXi, Syn. of CYANATE OF PHENYL. (See CYANIC ETHERS.) 
 
 CARBANXXiXDE. Syn. of DIPHENYL-CARBAMIDE (p. 756). 
 
 CARBANTX.XC AC 133. Syn. of PHENYL-CARBAMIC ACID (p. 751). 
 
 CARBAKTILETHAKE and C ARBANIIVTET HTTI.ANE. PHENYLCAR- 
 BAMATES OF ETHYL and METHYL (p. 752). 
 
 GARB AZOTE. The name given by Thau low (J. pr. Chem. xxxi. 220) to the 
 gas evolved by ignition of cyanide of silver, which he regards as isomeric but not 
 identical with, cyanogen. It has a peculiar odour, and strongly irritates the eyes and 
 respiratory organs. Specific gravity 173. Liquefies at 4 C. Burns with red 
 flame. It dissolves in potash, and the solution when neutralised with nitric acid does 
 not precipitate iron-salts. (Thau low.) 
 
 CARBAZOTXC ACXX>. Syn. with PICRIC ACID. 
 
 CARBIDES, or Carburets. Compounds of carbon with metals. These com- 
 pounds have not been much studied : none of them occur as natural minerals, and it 
 is difficult to obtain them in definite form. The usual effect of the union of carbon 
 with a metal, is to render it hard and brittle. (See the several metals.) 
 
 CARBOBZWZXDE. Syn. with BENZONE. 
 CARBOB4EOTZOXC ACID. See CINNAMEIN (p. 981). 
 CArtBO-HlTDROGETCS. See HYDROCARBONS. 
 
 CARBOLIC ACX3>. Syn. with PHENIC Aero. 
 
 CARBON*. Symbol C. Atomic weight 12. Carbon is one of the most abundant 
 of the elements, existing both in the free state and in an endless variety of combina- 
 tions. It is found pure in the diamond ; nearly pure in graphite or plumbago, less 
 pure as anthracite. It occurs also abundantly in the form of carbonates, especially 
 carbonate of calcium, and is an essential constituent of organic bodies, from which 
 it may be separated in the form of charcoal, by distilling off the more volatile elements, 
 hydrogen, oxygen, nitrogen, &c. 
 
 Carbon in the free state is a solid body, destitute of taste and odour, infusible and 
 non- volatile, excepting at the temperature produced by a powerful electric current. The 
 several modifications exhibit great diversities of colour, lustre, transparency, hardness, 
 density, and power of conducting heat and electricity. It exhibits crystalline forms 
 belonging to two different systems, the regular and the hexagonal, and several amor- 
 phous modifications. 
 
 1. Diamond. This valuable gem consists of pure or nearly pure carbon. It is 
 found in alluvial soils produced by the disintegration of ancient rocks, the principal 
 localities being in India, Borneo, Brazil, and the Urals. Diamonds occur thinly 
 scattered through large quantities of soil, and very careful washing and examination 
 are required to separate them. 
 
 The diamond crystallises in forms belonging to the regular system, namely, the oc- 
 tahedron, which is usually the predominating form, though it rarely occurs alone ; also 
 the cube, the rhomboidal dodecahedron, which is very frequent ; the triakis-octahedron, 
 a figure of 24 faces, formed by the superposition of a low triangular pyramid on 
 each face of the octahedron ; and the hexakis-octahedron, a 48-sided figure formed 
 in like manner, by a 6 -faced acumination of the octahedron. Intermediate forms are 
 also of frequent occurrence, the secondary faces being sometimes so numerous as to 
 give the crystal the appearance of having convex faces. Sometimes the faces are really 
 curved, and consequently intersect in curved edges : the dodecahedron and octahedron 
 frequently occur with convex faces. Hemihedral forms and twin-crystals are also found. 
 (For figures, see the article CRYSTALLOGRAPHY.) 
 
 All diamonds cleave easily in directions parallel to other faces of the regular octa- 
 hedron, which is therefore the primary form. The fracture is conchoi'dal. The 
 
 3 c 3 
 
758 CARBON. 
 
 specific gravity of the diamond is 3'5295 according to Thomson ; 3*55 according fo 
 Pelouze. It is the hardest substance known, being capable of scratching all others. 
 Diamonds with curved edges are also capable of cutting glass, and are much used 
 for that purpose, the curved edges penetrating the glass like a wedge ; those with straight 
 edges merely scratch. 
 
 The purest diamonds are colourless and transparent ; but many exhibit various shades 
 of yellow, red, green, brown, and black; these coloured diamonds leave, when burnt, 
 from 065 to 0'2 per cent, of ash : colourless diamonds leave but a trace. The diamond 
 has a strong lustre (called adamantine), and high refractive and dispersive power ; 
 hence its peculiar brilliancy. The lustre of the natural diamond is greatly increased 
 by cutting it in a peculiar manner, so as to give it numerous facets capable of reflecting 
 and dispersing light in various directions. This is effected by pressing the diamond 
 against a revolving metal disc covered with a mixture of diamond dust and oil, no 
 other substance being hard enough to abrade the diamond. The dust for this purpose 
 is obtained either by collecting that which falls away in the process of cutting and 
 polishing, or by pounding up diamonds which have not sufficient transparency to be 
 valuable as gems. Diamonds are sometimes found in opaque spheroidal lumps, desti- 
 tute of crystalline structure and transparency, and useless excepting in the form of 
 powder. 
 
 The diamond conducts electricity but slowly. Like all other forms of carbon, it 
 neither melts nor volatilises at the heat of the most powerful furnace ; but when placed 
 between the charcoal cones of a powerful voltaic battery, it becomes white-hot, swells 
 up, splits into fragments, and after cooling, presents the aspect of coke prepared from 
 bituminous coal. When very strongly heated in the air or in oxygen gas, it takes fire 
 and burns completely away, forming carbonic anhydride. This fact of the combusti- 
 bility of the diamond, which had been conjectured by Newton from its great refracting 
 power, was first demonstrated in 1694, by the Florentine academicians, who succeeded 
 in burning it in the focus of a concave mirror. Lavoisier and Guyton-Morveau, and 
 afterwards Davy, showed that the sole product of the combustion in oxygen is carbonic 
 anhydride, and therefore that the diamond is pure carbon. 
 
 2. Graphite. This name is applied to several varieties of native carbon containing 
 from 95 to nearly 100 per cent, of that element, some crystalline, others amorphous, 
 but all perfectly opaque, having an iron-black or steel-grey colour, and metallic lustre, 
 producing a black shining streak on paper; sectile ; of specific gravity 1'2()9, hardness 
 between 1 and 2, and conducting electricity nearly as well as the metals. Graphite 
 was formerly regarded as a carbide of iron, but the iron is now known to be merely in 
 a state of mixture, as also small quantities of silica and alumina. 
 
 a. Crystallised or Foliated Graphite. This variety is found occasionally in small 
 six-sided tables belonging to the hexagonal system, cleaving perfectly in the direction 
 of the base, and having the basal planes striated parallel to the alternate sides. More 
 commonly, however, it occurs in foliated or granular masses. It is found imbedded in 
 quartz near Travaneore in Ceylon, and near Moreton Bay in Australia ; with olivine 
 and sphene at Ticonderoga in the State of New York, and in gneiss at Stourbridge, 
 Massachussets, where it presents a structure between scaly and fine granular, and an 
 occasional approximation to distinct crystallisations (Dan a, ii. 27). It is also obtained 
 artificially by melting cast-iron containing a large proportion of carbon and leaving it 
 to cool slowly. It is tough and difficult to pulverise by mechanical means, bxit it may 
 be reduced to the state of very thin laminae by prolonged trituration with water. 
 
 0. Amorphous Graphite. This variety, also called plumbago or black lead, is found 
 in Borrowdale, Cumberland, where it occurs in nests of trap in the clay-slate, and is 
 largely imported into this country from Germany, principally from Griesbach near 
 Passau. The Borrowdale mine was formerly very rich, but now appears to be nearly 
 exhausted (see lire's Dictionary of Arts. Manufactures and Mines, iii. 467). Amor- 
 phous graphite is softer than the crystalline variety, and makes a much blacker streak 
 on paper : it is therefore better adapted for the making of pencils. Some kinds of 
 amorphous graphite, occurring in the coal measures, have very much the appearance 
 of anthracite : such is the case with the graphite of New Brunswick. 
 
 Graphite resembles the other modifications of carbon in being unalterable when 
 heated in close vessels, excepting at the temperature of the electric current, and in yield- 
 ing carbonic anhydride when burnt in contact with oxygen. But it differs essentially 
 from all other forms of carbon when subjected to the action of certain oxidising agents, 
 such as a mixture of chlorate or acid cliromate of potassium with sulphuric or nitric 
 acid, or a mixture of nitric and sulphuric acids. In this case Brodie has shown (Ann. 
 Ch. Phys. [3] xlvi. 351 ; further, Phil. Trans. 1860, i. ; Ann. Ch. Pharm. cxiv. 7) that 
 it is converted into a peculiar acid, called graphitic acid, which is best obtained by 
 heating pulverised graphite with chlorate of potassium and nitric acid, as long as 
 yellow vapours are given off, then washing it with a large quantity of water, drying it 
 
CARBON. 759 
 
 on the water-bath, and repeating this series of operations several times. In this manner 
 the graphite is ultimately converted into thin transparent crystals of graphitic acid, 
 CVirO 8 . Brodie, however, regards this acid as analogous in composition to the acid 
 Si 4 H 4 0\ which Wohler obtained by the action of oxidising agents on graphitoi'dal silicon ; 
 and accordingly he supposes that the atomic weight of graphite is different from that 
 of the other forms of carbon, and equal to 33, which he denotes by the symbol Gr 
 (graphon) ; substituting this value in the preceding formula of graphitic acid, it be- 
 comes Gr 4 H'CK (See ATOMIC WEIGHT OF CABBON, p. 757 ; also GBAPHITIC Aero.) 
 
 Graphite cannot be converted into graphitic acid by a single treatment with oxidis- 
 ing agents, however long continued; but by subjecting it to this treatment for a cer- 
 tain time, then washing it with water and igniting, it may be purified and obtained in 
 a state of very minute division. A good way of proceeding is to mix coarsely 
 pounded graphite with of its weight of chlorate of potassium, add the mixture to a 
 quantity of strong sulphuric acid equal to twice the weight of the graphite, heat the 
 whole in the water-bath as long as yellow vapours of chloric oxide are evolved, wash 
 the cooled mass with water, then dry and ignite it ; it then swells up and leaves finely 
 divided graphite. If the graphite to be purified contains siliceous matters, a little 
 fluoride of sodium should be added to the mixture before heating. 
 
 Graphite is used for making pencils, for polishing stoves, and other articles, for 
 diminishing the friction of machinery, for making crucibles, and in the electrotype 
 process for coating the surfaces of wood and other non-conducting materials, so as to 
 render them conductive. 
 
 3. Anthracite or stone-coal is an amorphous variety of carbon containing about 90 
 per cent, of that element associated with hydrogen, oxygen, nitrogen, and ash. It is 
 intermediate in composition and properties between graphite and bituminous coal, 
 being blacker than graphite, and having a higher lustre than ordinary coal. Specific 
 gravity 1*3 to 17. Hardness = 2 to 2'1. It burns with difficulty, requiring a strong 
 draught to keep it in a state of active combustion : hence it is fit only for burning in 
 close stoves and furnaces ; it does not cake together like bituminous coal. Anthracite 
 occurs abundantly in South Wales, in the departments of Mayenne and Isere in 
 France ; also in Pennsylvania and Ehode Island. 
 
 4. Carbon obtained from Organic Substances by Dry Distillation or 
 Imperfect Combustion. When animal or vegetable substances are strongly heated 
 in close vessels, the more volatile elements, viz. the oxygen, hydrogen, and nitrogen, 
 with part of the carbon, are driven off in the form of gaseous products, some of which 
 afterwards condense in the liquid form, while a considerable portion of the carbon re- 
 mains behind in the form of a black mass, called charcoal, of greater or less compactness, 
 according to the nature of the original substance. If the substance thus treated wood 
 or coal, for example contains any inorganic materials, such as potash, soda, lime, &c., 
 these remain behind with the charcoal. The purest kind of charcoal is that obtained 
 by heating sugar, starch, or some other organic substance, free from inorganic elements, 
 in a close vessel. There then remains a black, brilliant, porous charcoal, which is 
 nearly pure carbon, but contains a small quantity of hydrogen and oxygen, which cannot 
 be driven off even by the most intense and long-continued heat. 
 
 a. Wood- Char coal. Wood consists of carbon, hydrogen, and oxygen, the two latter 
 being in the proportion to form water. When heated in the open air, it burns com- 
 pletely away, with the exception of a small quantity of white ash ; but if the supply 
 of air is limited, only the more volatile ingredients burn away, and the greater part of 
 the carbon remains behind. This is the principle of the process of charcoal-burning 
 as it is practised in countries where wood is abundant, on the Harz mountains in 
 Germany, for instance. A number of billets of wood are built up vertically in two or 
 three rows into a large conical heap, which is covered over with turf or moistened 
 charcoal-ash, holes being left at the bottom for the air to get in. A hollow space is 
 also left in the middle of the heap, to serve as a flue for the gaseous matters which 
 are evolved. The heap is set on fire by throwing burning pieces of wood into the 
 central opening, near the top of which, however, a kind of grate, made of billets of 
 wood, is placed, to prevent the burning fuel from falling at once to the bottom. The 
 combustion then proceeds gradually from the top to the bottom, and from the centre 
 to the outside of the heap ; and as the central portions burn away, fresh wood is con- 
 tinually thrown in at the top, so as to keep the heap quite full. The appearance of 
 the smoke shows how the combustion is proceeding ; when it is going on properly, the 
 smoke is thick and white ; if it becomes thin, and especially if a blue flame appears, 
 it is a sign that the wood is burning away too fast, and the combustion must then be 
 checked by partially stopping up the holes at the bottom, or by heaping fresh ashes on 
 the top and sides, and pressing them down well so as to diminish the draught. As 
 soon as the combustion is completed, the heap is completely covered with turf or ashes, 
 and left to cool for two or three days. It is then taken to pieces, and the portions 
 
 3 c 4 
 
760 CARBON. 
 
 still hot are cooled by throwing water or sand upon them. The quantity of charcoal 
 thus obtained varies with the manner in which the combustion is conducted. 100 parts 
 of wood yield on the average from 61 to 65 parts by measure, or 24 parts by weight 
 of charcoal. When the burning is very carefully conducted, the quantity may amount 
 to 70 per cent, by measure. 
 
 In England a large quantity of charcoal is obtained in the dry distillation of wood 
 for the preparation of acetic acid. For this purpose the wood is heated to redness in 
 cast-iron cylinders, whereupon a number of volatile products are given off, including a 
 large quantity of tarry matter, an inflammable spirit called wood-spirit or wood-naphtha, 
 and acetic acid ; and in the retorts there remains a quantity of charcoal. 
 
 For the manufacture of gunpowder, charcoal is sometimes prepared by subjecting 
 wood in iron cylinders to the action of over-heated steam. (Violette, Ann. Ch. 
 Phys. [3] xxiii. 475.) 
 
 Wood-charcoal is more or less compact, according to the kind of wood from which it 
 is formed. The lighter woods, such as willow, yield a very porous charcoal, having 
 comparatively little power of conducting heat and electricity ; box- wood, on the 
 contrary, yields a very compact charcoal, which is a good conductor of heat and 
 electricity, and is admirably adapted for exhibiting the voltaic light. The density 
 and conducting power of charcoal are greatly increased by exposing it in close vessels 
 to a very high temperature. Charcoal retains the form, and to a considerable extent 
 the external structure of the wood, so that a horizontal section exhibits distinctly the 
 concentric rings and the traces of the medullary rays. When burned it leaves from 
 1 to 5 per cent, of ash. According to Berthier, 1000 parts of Mine-wood leave 50 parts 
 of ash ; of oak, 25 ; birch 10; fir 8 ; hornbeam 26 ; beech 30. 
 
 b. Coke. Ordinary bituminous coal, which consists of the remains of ancient forests 
 and peat-mosses, and appears to have been formed from wood by a process of slow 
 decay going on without access of air, differs from wood in containing a larger proportion 
 of carbon, and less oxygen and hydrogen ; it also contains nitrogen derived from the 
 tissue of the plants. This substance, when heated in the open air, burns away like 
 wood, leaving nothing but a white ash ; but, when strongly heated in east-iron cylin- 
 ders, it undergoes a decomposition like that which takes place in wood under similar 
 circumstances, a large quantity of volatile products being given off, viz, carburetted 
 hydrogen gas (the gas used for illumination) and a tarry liquid containing ammonia 
 and a variety of other products ; while a black, dull-looking, porous moss, called coke, 
 is left in the retorts. This substance also consists mainly of carbon, mixed, however. 
 with a quantity of inorganic constituents, greater than that which occurs in wood-char- 
 coal, so that it leaves a larger amount of ash when burned. The aspect of coke varies 
 greatly according to the kind of coal from which it is obtained. Bituminous coals, 
 such as the Newcastle coal, undergo a kind of semi-fusion before they decompose, and 
 yield a very porous coke, having a brilliant metallic aspect; anthracite, on the contrary 
 undergoes but little alteration by heating, and yields a coke having very much of the 
 form and aspect of the original mass. Coke is used in the iron districts of South 
 Wales and Staffordshire, for reducing the metal from the ore. It is there prepared 
 from the coal which occurs in the same districts, by partially burning that substance 
 in longitudinal heaps, more or less covered up with the ashes of former fires, the object 
 being to produce a smothered combustion, similar to that already described as used for 
 the preparation of wood-charcoal. This process is very wasteful unless carefully con- 
 ducted. 
 
 c. Metallic Carbon, Glance-coal. This is a very dense form of carbon, deposited 
 when certain volatile organic compounds, especially hydrocarbons, are passed through 
 red-hot tubes of porcelain or cast-iron ; it collects in the upper part of the retorts in 
 which carburetted hydrogen gas is distilled from coal, and is likewise produced in 
 blast furnaces. It often exhibits the lustre and sonority of a metal, is very hard, a 
 good conductor of heat and electricity, and burns with difficulty. It is used to form 
 the negative element in Bunsen's voltaic battery. 
 
 A very hard and compact carbon, also used for the purpose just mentioned, is ob- 
 tained by heating to redness, in an iron mould, an intimate and impalpable mixture 
 of 2 pts. coke and 1 pt. bituminous coal, then several times steeping it in treacle, and 
 subjecting it again to a very intense heat. The mass thus formed is very hard, may be 
 sawn and filed without breaking, and conducts electricity like a metal. 
 
 d. Lamp-black. Most of our ordinary combustibles, consisting of carbon and hy- 
 drogen, such as tallow, wax, and oil, undergo but imperfect combustion, unless assisted 
 by an artificial draught of air. The consequence is, that a portion of the carbon, 
 which is the less combustible element of the two, remains unburned, and is driven off 
 in smoke, or deposited on cold surfaces in the form of soot or lamp-black; thus, a plate 
 of glass or metal held in the upper part of a candle flame is quickly covered with a 
 black deposit of carbon. Lamp-black is ordinarily prepared by the imperfect combus- 
 
CARBON. /61 
 
 tion of highly carbonised bodies, such as resin or pitch. The apparatus consists of a 
 cylindrical stone chamber, in which is suspended a cone of iron plate, having a hole at 
 top, and capable of moving up and down ; this cone serves for a chimney during the 
 operation. A cast-iron pot, containing the resin or pitch, is heated in a furnace out- 
 side the chamber ; the vapours proceeding from it are set on fire ; and the supply of 
 air is properly regulated by apertures which may be opened and closed at pleasure. 
 The imperfect combustion of the vapour produces a considerable quantity of lamp- 
 black, which collects on the cone and on the walls. When the operation is finished, the 
 cone is lowered, and as it is made to fit the chamber exactly, it scrapes the wall us it 
 descends, and causes the deposit to fall down on the floor. Lamp-black thus obtained 
 is always contaminated with oily matter ; it may be purified by calcination in a covered 
 crucible. Sometimes the chamber is hung with coarse cloths, on which the soot col- 
 lects ; they are withdrawn from time to time and scraped. 
 
 A better method of condensation is to cause the smoke and vapour to pass through 
 an inclined iron tube, in which the oily products collect, and thence into a series of con- 
 densing chambers ; the purest product is then found in the farthest chamber. The 
 finest kind of lamp-black is obtained by burning oil or fat in lamps, and causing the 
 products of combustion to pass through a series of iron cylinders, terminating in a 
 chimney ; the cylinders are opened at bottom from time to time, and the carbonaceous 
 deposit removed. As obtained by either of these methods it is always more or less 
 contaminated with oily matter. It may be purified by calcination in a covered crucible, 
 but for the purposes to which it is chiefly applied, viz. for painting and for the manufac- 
 ture of printing ink, the presence of the oil is not objectionable. 
 
 e. Animal Charcoal or Bone-black, is a mixture of very finely divided charcoal and 
 phosphate of calcium obtained by calcining bones in close vessels. Its preparation and 
 properties have been already described (p. 624). 
 
 Absorbent -power af Charcoal. Wood-charcoal and other porous forms of carbon 
 have the property of absorbing large quantities of gases : the greater the porosity of the 
 charcoal the greater is also its absorbing power. In its ordinary state, however, charcoal 
 has its pores filled with atmospheric air, and to enable it to exert its full absorbing power 
 on any other gas, it must first be freed from the air contained in it by heating it to red- 
 ness and cooling it under mercury. Saussure has shown that recently ignited box- 
 wood charcoal absorbs at 12 C. and under a pressure of 724 millimetres, the follow- 
 ing quantities of different gases : 
 
 Ammonia . . 90 vols. Ethylene . 35 vols. 
 
 Hydrochloric acid . 85 
 
 Sulphurous anhydride 65 
 
 Sulphydric acid . . 55 
 
 Nitrous oxide . . 40 
 
 Carbonic oxide 
 Oxygen . . 
 Nitrogen 
 Hydrogen 
 
 9-42 
 9-25 
 6-50 
 1-25 
 
 Carbonic anhydride . 35 
 
 Charcoal also absorbs moisture with avidity from the air, as well as other conden- 
 sable vapours, such as odoriferous efiiuvia. Hence freshly calcined charcoal, wrapped 
 up in clothes which have acquired a disagreeable colour, destroys that odour. It has a 
 considerable effect in retarding the putrefaction of animal matter with which it is 
 placed in contact. Water is found to remain sweet, and wine to be improved in quality, 
 if kept in casks the inside of which has been charred. In the state of coarse powder, 
 wood-charcoal is particularly applicable as a filter for spirits, which it deprives of the 
 essential oil they contain. (Graham's Elements of Chemistry, 2nd ed. vol. i. p. 338.) 
 Water contaminated with offensive gas and other matters may also be rendered fit 
 for drinking by filtering it through coarsely pounded charcoal interposed between two 
 layers of sand. 
 
 Charcoal not only absorbs gases, but frequently also determines their combination. 
 If a piece of charcoal, which has remained for some time in an atmosphere of sulphu- 
 retted hydrogen, and has absorbed a considerable quantity of that gas, be introduced 
 into a vessel filled with oxygen, combination immediately takes place between the 
 oxygen and the elements of the sulphuretted hydrogen, water and sulphurous acid 
 being formed, and a portion of the sulphur separated. The charcoal always becomes 
 very hot, and sometimes the heat is great enoiigh to produce explosion. Similar phe- 
 nomena are exhibited by other combustible gases. 
 
 This property of charcoal has been applied by Dr. Stenhouse to the construction of 
 ventilators and respirators for purifying infected atmospheres. In a pamphlet, bearing 
 the title " On Charcoal as a Disinfectant," Dr. Stenhouse observes : " Charcoal not 
 only absorbs effluvia and gaseous bodies, but, especially, when in contact with atmo- 
 spheric air, rapidly oxidises and destroys many of the easily alterable ones, by resolving 
 them into the simplest combinations they are capable of forming, which are chiefly 
 water and carbonic acid. . . . Effluvia and miasmata are generally regarded as 
 
762 CARBON. 
 
 highly organised, nitrogenous, easily alterable bodies. When these are absorbed by 
 charcoal, they come in contact with highly condensed oxygen gas, which exists within 
 the pores of all charcoal which has been exposed to the air, even for a few minutes ; 
 in this way they are oxidised and destroyed." On this principle, Dr. Stenhouse has 
 constructed ventilators, consisting of a layer of charcoal enclosed between two sheets 
 of wire-gauze, to purify the foul air which accumulates in water-closets, the wards of 
 hospitals, and in the back courts and lanes of large cities. By the use of these venti- 
 lators, pure air may be obtained from exceedingly impure sources, the impurities being 
 absorbed and retained by the charcoal, while a current of pure air alone is admitted 
 into the neighbouring apartments. A similar contrivance might also be applied to the 
 gulley-holes of our common sewers, and to the sinks in private houses. Dr. Stenhouse 
 has also constructed respirators, consisting of a layer of charcoal a quarter of an inch 
 thick, interposed between two sheets of silvered wire-gauze covered with woollen cloth. 
 They are made either to cover the mouth and nose, or the mouth alone ; the former 
 kind of respirator affords an effectual protection against malaria and the deleterious 
 gases which accumulate in chemical works, common sewers, &c. The latter will 
 answer the same purpose when the atmosphere is not very impure, provided the simple 
 precaution be taken of inspiring the air by the mouth, and expiring by the nose. This 
 form of respirator may also be useful to persons affected with fetid breath. Freshly 
 heated wood-charcoal simply placed in a thin layer in trays, and disposed about in- 
 fected apartments, such as the wards of hospitals, is also highly efficacious in absorbing 
 the noxious matter. 
 
 Platinised Charcoal. The power of charcoal in inducing chemical combination is 
 increased by combination with minutely divided platinum. In this manner, a com- 
 bination may be produced possessing the absorbent power of charcoal (which is much 
 greater than that of spongy platinum), and nearly equal, as a promoter of chemical 
 combination, to spongy platinum itself. In order to platinise charcoal, nothing more 
 is necessary than to boil it, either in coarse powder or in large pieces, in a solution of 
 di chloride of platinum, and, when thoroughly impregnated, which seldom requires 
 more than ten minutes or a quarter of an hour, to heat it to redness in a closed vessel, 
 a capacious platinum crucible being well adapted for the purpose. Charcoal thus 
 platinised, and containing 3 grains of platinum to 50 grains of charcoal, causes oxy- 
 gen and hydrogen gases to unite completely in a few minutes ; with a larger proportion 
 of platinum, the gases combine with explosive violence, just as if platinum-black were 
 used. Cold platinised charcoal, held in a jet of hydrogen, speedily becomes incan- 
 descent, and inflames the gas. Platinised charcoal slightly Warmed rapidly becomes 
 incandescent in a current of coal gas, but does not inflame the gas, owing to the very 
 high temperature required for that purpose. In the vapour of alcohol or wood-spirit, 
 platinised charcoal becomes red-hot, and continues so till the supply of vapour is ex- 
 hausted. Spirit of wine, in contact with platinised charcoal and air, is converted in a 
 few hours into vinegar. Two per cent, of platinum is sufficient to platinise charcoal 
 for most purposes. Charcoal containing this amount of platinum, causes oxygen and 
 hydrogen to combine perfectly in about a quarter of an hour, and such is the strength 
 of platinised charcoal which seems best adapted for disinfectant respirators. Charcoal 
 containing only 1 per cent, of platinum causes oxygen and hydrogen to combine in 
 about two hours ; and charcoal containing the extremely small amount of \ per cent, 
 of platinum, produces the same effect in six or eight hours. Platinised charcoal seems 
 likely to admit of various useful applications ; one of the most obvious of these is its 
 adaptability to air-filters and respirators. From its powerful oxidising properties, 
 it might also prove a highly useful application to malignant ulcers and similar sores, on 
 which it will act as a mild but effective caustic. It might also be found useful in 
 Bunsen's carbon battery. (Stenhouse, Chem. Soc. Qu. J. viii. 105.) 
 
 Charcoal as a Precipitant and Dccoloriser. Wood-charcoal and animal charcoal, 
 especially the latter, possess the power of forming insoluble compounds with many 
 dissolved substances, more particularly organic colouring matters. It precipitates 
 iodine from its solution in iodide of potassium, also lime, nitrate of lead, and most 
 metallic sub-salts, from their aqueous solutions : it likewise separates metallic acids 
 from their solutions in alkalis. A solution of acetate or nitrate of lead, in which char- 
 coal is immersed, is found after a while to contain free acetic or nitric acid. A large 
 number of organic substances, besides colouring matters, are likewise precipitated by 
 charcoal, viz. the bitter principles of the hop, gentian, and aloes, tannin, organic alka- 
 loids ; also resins from solution in alcohol. It is important to bear this in mind in 
 analysing liquids which have been decolorised by animal charcoal, as many of the sub- 
 stances originally contained in the solution may have been carried down by the charcoal. 
 
 The peculiar power of bone-black in removing colouring matters, &c. from solution, 
 is due to the more minute division of the charcoal resulting from the interposition of 
 the earthy matter. If this be dissolved out by an acid, the decolorising power of thu 
 
CARBON. 
 
 763 
 
 charcoal is greatly impaired, which however must be done for certain applications of 
 it, as in the preparation of vegetable acids. Charcoal of much higher decolorising 
 power than bone-black, is obtained by calcining dried blood, horns, hoofs, clippings of 
 hides, glue, and other animal matters, in contact with pearl-ash, and washing the cal- 
 cined mass with water. A charcoal of considerable decolorising power may likewise 
 be prepared by carbonising vegetable substances mixed with chalk, calcined flints, or 
 any other earthy matter. If 100 pts. of pipe-clay, made into a thin paste with water, 
 be well mixed with 20 pts. of tan and 500 pts. of finely pounded coal, and the mass 
 dried and ignited in a close vessel, a charcoal will be obtained very little inferior in 
 decolorising power to bone-black. The following table, taken from Graham's Elements 
 of Chemistry, 2nd edition, vol. i. p. 361, shows the efficiency of different kinds of 
 charcoal in removing colouring matter. These substances are compared with bone- 
 black, as being the most feeble species. The relative efficiency is not the same for 
 different kinds of colouring matter. 
 
 SPECIES OF CHARCOAL. 
 (same weight). 
 
 Relative decolora- 
 tion of sulphate of 
 indigo. 
 
 Relative decolo- 
 ration of syrups. 
 
 Blood charred with pearlash 
 
 50 
 
 20 
 
 Blood charred with chalk 
 
 18 
 
 11 
 
 Blood charred with phosphate of calcium . 
 
 12 
 
 10 
 
 Glue charred with pearlash . . . 
 
 36 
 
 15-5 
 
 White of egg charred with the same 
 
 34 
 
 15-5 
 
 Gluten charred with the same . 
 
 10-6 
 
 8-8 
 
 Charcoal from acetate of potassium . 
 
 5-6 
 
 4-4 
 
 Charcoal from acetate of sodium 
 
 12 
 
 8-8 
 
 Lamp-black not calcined .... 
 
 4 
 
 3-3 
 
 Lamp-black calcined with pearlash . 
 
 15-2 
 
 10-6 
 
 Bone-charcoal, after the extraction of the 
 
 
 
 earth of bones by an acid, and calcina- 
 
 
 
 tion with potash 
 
 45 
 
 20 
 
 Bone-charcoal, treated with an acid . 
 
 1-87 
 
 1-6 
 
 Oil charred with phosphate of calcium 
 
 2 
 
 1-9 
 
 Bone-charcoal in its ordinary state . 
 
 1 
 
 1 
 
 [On the preparation, properties, and uses of the various forms of carbon, see further. 
 lire's Dictionary of Arts, Manufactures and Mines, articles BONE-BLACK, CHARCOAL, 
 COKE, and LAMP-BLACK. Pelouz e et Fremy, Traite de Chimic, 3 rae ed. i. 705821.] 
 
 Compounds of Carbon. Carbon unites with most other elements, but generally 
 speaking not directly, most of its compounds being formed either in the bodies of living 
 plants and animals in a way which we cannot trace, or derived by substitution from such 
 compounds. The only elements with which it unites directly are oxygen, sulphur, nitro- 
 gen, and a few metals, and with these only at high temperatures. For oxygen, carbon 
 exhibits no affinity at ordinary temperatures, but at a red heat, it not only combines 
 readily with free oxygen, but is capable of separating that element from its combinations 
 with all others, even from potassium. The temperature required for determining the 
 combination depends upon the density of the carbon : porous wood charcoal begins to 
 burn in the air at about 240 C. ; the more compact kinds require a higher temperature ; 
 anthracite and graphite still higher ; and the diamond the highest of all. The product 
 of the combustion is carbonic anhydride, CO 2 , mixed, however, if the supply of oxygen 
 is deficient, with the lower oxide CO. 
 
 With sulphur, carbon also unites at a red heat, forming disulphide of carbon, CS 2 . 
 With nitrogen, it unites at a red heat, provided an alkali be present, forming cyanogen, 
 CN, which enters into combination with the alkali-metal ; thus, when nitrogen gas is 
 passed oyer ignited charcoal saturated with carbonate of potassium, cyanide of potas- 
 sium is formed. With metals also, carbon appears to unite directly under certain cir- 
 cumstances, as in the formation of steel by keeping iron imbedded in charcoal powder 
 at a white heat. 
 
 The compounds of carbon and hydrogen constitute a very important group of organic 
 bodies, many of them, as oil of turpentine, C 10 H 16 , existing ready formed in plants, 
 while others, as ethylene, C 2 H 4 , and naphthalene, C'H 8 , are produced by the decom- 
 position of more complex organic compounds. Most of them play the part of radicles, 
 being capable of combining, like metals, with chlorine, oxygen, sulphur, &c., of re- 
 placing hydrogen in combination, and passing as entire groups from one state of com- 
 
764 CARBON : CHLORIDES OF. 
 
 bination to another : e.g. ethyl, C 2 H & , amyl, C 5 H n , allyl, C 3 H 5 , ethylene, C 2 H 4 , amy* 
 hue, C 5 H 10 , &c. The hydrogen in these hydrocarbons, may be more or less replaced 
 by chlorine, bromine, nitryl (NO 2 ), and other elements or groups, whereby derivative 
 radicles are formed, also capable of entering into combination, replacing hydrogen, &c. 
 like simple radicles, c. g. bromethyl, C 2 H 4 Br, chlorcthylene, C 2 H 3 C1, dinitronapkthalene, 
 C 10 H 6 (NO*) 2 , &c. When the hydrogen in a hydrocarbon is thus completely replaced by 
 another element, a chloride, bromide, &c. of carbon is produced. In this manner, 
 tetrachloride of carbon CC1 4 , is formed from marsh-gas CH 4 , dichloride of carbon, 
 C-'Cl 4 , from ethylene, C 2 H 4 , &c. 
 
 CARBON, BROMIDES OP. Several of these compounds appear to exist, but 
 only one of them, the dibromide C 2 Br 4 , has been analysed.*- This body is obtained by 
 treating alcohol or ether with bromine, saturating the resulting hydrobromic acid 
 with potash, distilling, and treating the residue with water. Dibromide of carbon 
 then remains as a white crystalline deposit which may be purified by washing with water 
 (Lowig, Ann. Ch. Pharm. iii. 292). Its formation is represented by the equations : 
 
 C 2 H 8 + 4Br 2 = C 2 Br 4 + 4HBr + H 2 0. 
 
 Alcohol. 
 
 C 4 H 10 + 8Br 2 = 2C 2 Br 4 + 8HBr + H 2 0. 
 Ether. 
 
 It is also produced by the action of alcoholic potash on the dibromide of tribromethy- 
 lene (Lennox, Chem. Soc. Qu. J. xiv. 209): 
 
 C 2 HBr".Br 2 + KHO = C 2 Br 4 + KBr + H 2 0. 
 
 Dibromide of carbon forms white crystalline plates, unctuous to the touch, having an 
 ethereal odour and saccharine taste ; it melts at 50 C., and sublimes without alteration. 
 It is nearly insoluble in water, very soluble in alcohol and ether ; not decomposed by 
 acids or alkalis. It burns in the flame of a spirit lamp, giving off vapours of hydro- 
 bromic acid, but ceases to burn as soon as it is removed from the flame. Chlorine 
 attacks it in the melted state, forming chloride of bromine. Heated with oxide of 
 mercury or passed over red-hot oxide of zinc, copper, or iron, it yields metallic bromine 
 and carbonic anhydride. When passed over red-hot metallic zinc, copper, or iron, it 
 also yields a bromide of the metal without disengagement of gas. (Lowig.) 
 
 Commercial bromine sometimes contains a liquid bromide of carbon, which may also 
 be obtained by the action of bromine on ether and alcohol, especially if chlorine is like- 
 wise present. It is an oily, colourless, fragrant liquid of specific gravity 2*43fr, not 
 solidifiable at 25 C., boiling at 120 C., so that it is easily separated from bromine by 
 distillation. It is insoluble in water, not decomposed by acids or dilute alkalis, but 
 decomposed by fusion with hydrate of potassium, into bromide and carbonate of potas- 
 sium (Poselger, Ann. Ch. Pharm. Ixiv. 287). The same compound appears to be 
 produced by the action of 2 pts. bromine on 1 pt. iodide of ethylene, C 2 H 4 I 2 , and may 
 be separated from bromide of iodine by means of dilute potash. 
 
 In the preparation of bromine, there is sometimes formed an oily ethereal liquid 
 called oil of bromine, which appears to contain C 2 H 8 Br 4 . When dropped on red-hot 
 fragments of glass, it yields a deposit of carbon, together with crystals and a dark -brown 
 oil, while hydrobromic acid and a combustible gas escape. The dark-brown oil appears 
 to be a portion of the liquid which has remained undecomposed and has absorbed 
 bromine, and the crystals consist of a bromide of carbon C 4 Br 2 . (M. Hermann, Ann. 
 Ch. Pharm. xcv. 211.) 
 
 CARBON, CHZiGRXDSS OP. Carbon does not unite directly with chlorine : 
 but several compounds of these elements are obtained by the action of chlorine, aided 
 by light or heat, on organic bodies, chiefly on hydrocarbons or their chlorinated deri- 
 vatives, e, g. CC1 4 from marsh-gas (CH 4 ), or chloroform (CHC1 3 ), C 2 C1 4 from ethylene 
 (C 2 H 4 ), C 3 C1 6 from tritylene (C 3 H 6 ), C 10 C1 8 from naphthalene (C H 8 ), &c. It is cus- 
 tomary, however, to restrict the term chloride of carbon to four of these bodies, 
 containing 1 and 2 atoms of carbon, while the rest are regarded as substitution-deriva- 
 tives of organic radicles, c. y. C C1 8 , as perchloronaphthalene. The names and formulae 
 of these four compounds are given in the following table, in the left-hand column, ac- 
 cording to the atomic weight of carbon [12] here adopted, in the right-hand column 
 according to the smaller atomic weight of carbon [6], the latter being the names by 
 which they are generally known : 
 
 [C - 12] [<7 - 6] 
 
 Protochloride . . C ? C1 2 or Subchloride . . &CP 
 
 Dichloride . . . C*C1* Protochloride. . C*Cl* 
 
 Trichloride. . . C 2 C1 8 Sesquichloride . (POP 
 
 Tetrachloride . . CC1 4 Di- or Bi-chloride . C*Cl* 
 
 * C 2 Br 6 has been recently obtained. See ETHYLENES, BROMINATBD. 
 
CARBON: CHLORIDES OF. 765 
 
 There is, however, no real distinction between these four compounds and others formed 
 of the same two elements, excepting that they are of lower atomic weight, and that 
 they may be derived from disulphide of carbon, the vapour of that substance mixed 
 with chlorine and passed through a hot tube yielding the tetrachloride, and the 
 other three being produced, either by exposing this compound to a higher temperature 
 or by the action of reducing agents. 
 
 TETRACHLORIDE OF CARBON, CC1 4 . Dichloride or Bichloride of Carbon. Car- 
 bonic chloride. Perchlorinated Chloride of Methyl. Ptrchloroformene. This compound, 
 which is an analogue of marsh-gas CH 4 , and of carbonic anhydride CO 2 , was disco- 
 vered by Kegnault in 1839 (Ann. Ch. Phys. [2] Ixxi. 337). It is produced: 1. By 
 the action of chlorine on marsh-gas (Dumas, Ann. Ch. Phys. [3] Ixxiii. 95). 2. By 
 the action of chlorine on chloroform in sunshine: CHCP + Cl 2 = HC1 + CC1 4 . 
 Chloroform is gently heated in a retort exposed to the sun, and a stream of dry chlo- 
 rine is passed slowly and continuously through it, the liquid which distils over being 
 repeatedly poured back till hydrochloric acid ceases to be evolved, after which the dis- 
 tillate is agitated with mercury to remove free chlorine, and then rectified (Kegnault). 
 3. By the action of chlorine on disulphide of carbon : CS 2 + 4C1 2 = CC1 4 + 2SC1 2 . 
 Chlorine saturated with vapour of sulphide of carbon by passing through the liquid is 
 made to pass through a red-hot tube containing fragments of porcelain and connected 
 with a receiver surrounded with ice ; and the yellowish-red mixture of tetrachloride of 
 carbon and chloride of sulphur thereby obtained is very slowly added to an excess of 
 potash-ley or milk of lime, the mixture being agitated from time to time and after- 
 wards distilled. Tetrachloride of carbon then passes over, sometimes mixed with 
 sulphide of carbon, if too much of that compound was mixed with the chlorine, or if 
 the heat was not strong enough ; the sulphide of carbon may be removed by leaving 
 the liquid for sometime in contact with potash-ley (Kolbe, Ann. Ch. Pharm. xlv. 41 ; 
 liv. 146). Greuther (ibid. cvii. 212) removes the sulphide of carbon, by dissolving 
 the mixture in alcohol, adding alcoholic potash as long as it thereby acquires a darker 
 colour, and heating the liquid gently to promote the conversion of the sulphide of carbon 
 into xanthate of potassium ; then separates the unaltered chloride of carbon by water ; 
 and purifies it by washing. 4. By the action of pentachloride of antimony on disulphide 
 of carbon : 
 
 CS 2 + 2SbCP = CC1 4 + 2SbCP + S 2 . 
 
 The mixture becomes hot, and on cooling deposits crystals of trichloride of antimony 
 mixed with sulphur, while tetrachloride of carbon remains in the liquid state. (Hof- 
 mann, Chem. Soc. Qu. J. xiii. 65.) 
 
 Propirtiis. Tetrachloride of carbon is a thin transparent colourless oil, having a 
 pungent aromatic odour. Specific gravity T56. Boiling point 77 C. Vapour-density 
 
 by experiment 5*24 5'33, representing a condensation to 2 vols. ( '- x 
 
 T.-OG93 5'34.) It is insoluble in water, but soluble in alcohol and in ether. 
 
 Decompositions. Tetrachloride of carbon passed through a red-hot tube, is resolved 
 into free chlorine and a lower chloride of carbon, which, at a bright red heat is chiefly 
 C-'Cl 4 , at a still higher temperature C 2 C1 2 , and at a dull red heat, a body isomeric with 
 C'-'CI 6 , but having only half the vapour-density of that compound (Eegnault). 
 2. When mixed with hydrogen and passed through a red-hot tube filled with pumice, it 
 yields marsh-gas and ethylene (Berth e lot, Ann. Ch. Phys. liii. 69; Jahresber. d. 
 Chem. 1858, p. 519). 3. With sulphuretted hydrogen, in like manner, at a low red 
 heat it yields hydrochloric acid and sulphochloride of carbon, CC1 4 -t IPS = 2HC1 -f 
 CSC1 2 (Kolbe). 4. Dissolved in weak alcohol and treated with amalgam of potas- 
 sium, it gives off part of its chlorine to the potassium, and yields chloroform, CHCP, 
 mono-chlorinated chloride of methyl, CH 2 C1 2 , and marsh-gas (Kegnault). 5. Treated 
 in a flask provided with an upright condensing tube with zinc and dilute acid, it yields 
 hydrochloric acid and chloroform, the latter being converted by the further reducing 
 action of the mixture, into a body containing still less chlorine, probably CIFCl 2 
 (Geuther, loc. cit.}&. It is not decomposed by aqueous potash or sulphydrate of 
 potassium; but alcoholic potash slowly converts it into chloride and carbonate of 
 potassium (Regnault). Heated with alcoholic potash to 100 C. in a sealed tube 
 for a week, it is partly converted into ethylene (Berthelot, Ann. Ch. Pharm. cix. 
 118). 7. Heated to 170 or 180 C. with 3 vols. phcnylamine, it yields carbotri- 
 phenyltriamine (Hofmann, Proc. Koy. Soc. ix. 284) : 
 
 6(N.H 2 .C 6 H 5 ) + CC1 4 = [N 2 .C.(C 6 H 5 ) 3 .H 2 ].HC1 + 3[(N.H 2 .C 6 H 5 ).HC1]. 
 
 Phenylamine. Hydrochlorate of carbotri- Hydrochlorate of 
 
 phenyltriamine. Phenylamine. 
 
 8. With triethylphosphine it yields a white crystalline product. (Hofmann, ibid x. 
 184.) 
 
766 CARBON: CHLORIDES OF. 
 
 A compound, CC1 4 S0 2 , formed by the action of moist chlorine on sulphide of carbon, 
 sometimes regarded as sulphite of tetrachloride of carbon, but more probably a chlori- 
 nated derivative of methyl-sulphuroits acid, will be described under that head. 
 
 TRICHLORIDE OF CARBON. C 2 C1 6 . Sesquichloride of Carbon, Perchhride of Car- 
 bon, Perchlorinated Chloride of Eihylene, Chlorure de Chloroxethose. This compound, 
 which was discovered and investigated by Faraday (Phil. Trans. 1826, p. 47), and 
 further by Regnault (Ann. Ch. Phys. [2] Ixix. 166; Ixxxi. 371), is produced by the 
 action of chlorine in sunshine on various compounds and derivatives of ethyl and 
 ethylene: 1. On dichloride of carbon, C 2 C1 4 (Faraday). 2. On chloride of ethylene : 
 C 2 H 4 CP + 4C1 2 = 4HC1 + C*C1 6 ; the action also takes place, though more slowly in 
 diffused daylight (Faraday), or with aid of heat (Liebig). 3. On chloride of ethyl, 
 first in the shade, afterwards in sunshine : O'H 5 C1 + 5C1 2 = 5HC1 + C 2 C1 6 (Laurent, 
 Ann. Ch. Phys. [2] Ixxxiv. 328) ; similarly on mono-, di-, or tri-chlorinated chloride of 
 ethyl (Regnault). 4. On sulphite of ethyl, with simultaneous formation of chlo- 
 ride of sulphury 1, chloraldehyde, and hydrochloric acid (Ebelmen and Bouquet, 
 Ann. Ch. Phys. [3] xvii. 66) : 
 
 (C 2 H 5 ) 2 S0 3 + 11C1 2 = C 2 C1 6 + S0 2 C1 2 + C 2 C1 4 + 10HC1. 
 
 5. On oxide of ethyl, which, in bright sunshine, is sometimes converted at once into 
 sesquichloride of carbon and chloraldehyde, sometimes into perchlorethylic oxide, 
 C 4 C1 10 O, 1 at. of which is resolved by distillation into C 2 C1 4 and C 2 C1 6 (Eegnault, 
 Malaguti). Several perchlorinated compound ethers (carbonic, succinic, &c.) also 
 yield trichloride of carbon, when similarly treated. 6. On hydrochlorate of ethy- 
 lamine ' 
 
 C 2 H 7 N + 5C1 2 = C 2 C1 + NH 4 C1 + 3HC1. 
 
 The sal-ammoniac is ultimately resolved by the excess of chlorine into hydrochloric 
 acid and nitrogen, which escapes, a certain portion, being, however, converted into chlo- 
 ride of nitrogen (Greuther and Hofacker, Ann. Ch. Pharm. cviii. 51). The formation 
 of chloride of nitrogen must render the process dangerous. 7. Tetrachloride of carbon 
 passed through a red-hot tube is resolved into the trichloride and free chlorine (p. 765). 
 
 Preparation. 1. Chloride of ethylene is exposed to the sun in a bottle filled with 
 chlorine, water being* frequently added in small portions to absorb the hydrochloric 
 acid produced, and the chlorine frequently renewed as long as any action is percep- 
 tible. The crystalline product is washed with water, pressed between bibulous paper, 
 heated to sublimation, then dissolved in alcohol, precipitated by water containing 
 potash, again washed with water, pressed, and dried in vacuo over sulphuric acid 
 (Faraday). By passing chlorine through chloride of ethylene, heated nearly to the 
 boiling point, part of that compound is converted into trichloride of carbon, which 
 crystallises out for the most part on cooling the liquid with ice (Liebig, Ann. Ch. 
 Pharm. i. 219). 2. A bottle filled with chlorine, and containing a little chloride of 
 ethyl, is set aside in the shade for twenty-four hours, the chlorine then renewed and 
 the vessel exposed to the sun : such exposure at the beginning of the process would 
 produce explosion (Laurent). Or better : vapour of chloride of ethyl produced by heat- 
 ing alcohol with strong hydrochloric acid, and purified by passing through water and 
 oil of vitriol, is brought in contact with chlorine in a vessel exposed to the summer sun 
 (Regnault). 3. Perchlorethylic oxide (C 4 C1 I0 0) is distilled, and the distillate is re- 
 peatedly treated with water, which takes up chloraldehyde and leaves trichloride of 
 carbon. (Malaguti, Ann. Ch. Phys. [3] xvi. 6, 14.) ^ 
 
 Properties. Trichloride of carbon crystallises in right rhombic prisms ooP, mo- 
 dified by the faces oo P oo and the horizontal prism P as. Angles of the prism ooP = 
 58 and 122 (Brooke) ; 59 and 121 (Laurent). The crystals are colourless, tran- 
 sparent, and nearly tasteless, but have an aromatic camphorous odour. They are as 
 hard as sugar, and easily pulverised. Specific gravity = 2 g O. Refracting power = 
 1-5767. They do not conduct electricity. They melt at 160 C. ; boil and sublime at 
 182, and volatilise even at ordinary temperatures. Vapour-density = 8*157, corre- 
 sponding to 2 volumes / 2 12 + 6 35 ' 5 x 0-0693 = 8-212V Insoluble in water, 
 
 soluble in alcohol, still more in ether ; the solutions are not clouded by nitrate of silver. 
 Soluble also in oils, both fixed and volatile. 
 
 Decompositions. 1. By repeated distillation, or by passing its vapour through a red- 
 hot porcelain tube, the trichloride is resolved into the dichloride, C 2 C1 4 , and free 
 chlorine. 2. It burns with a red light in the flame of a spirit-lamp, but is extinguished 
 on removal. 3. Passed, together with hydrogen, through a red-hot tube, it yields 
 hydrochloric acid and dichloride of carbon (G cut her), and undergoes a similar de- 
 composition when heated with sulphur, pJwsphorus, or iodine. 4. Most metals heated 
 in the vapour of the trichloride are converted into chlorides, with separation of char- 
 
CARBON : CHLORIDES OF. 767 
 
 coal 5. The vapour passed over red-hot baryta, strontia, or lime, yields a chloride 
 and carbonate of the metal, with deposition of charcoal ; with oxide of zinc, it some- 
 times forms oxychloride of carbon ; with the oxides of copper and mercury, and with 
 peroxide of lead, the products are metallic chloride and carbonic anhydride. 6. The 
 trichloride is not altered by distillation with aqueous or alcoholic potash ; but when 
 gently heated with an alcoholic solution of sulphydrate of potassium, it yields dichlo- 
 ride of carbon, together with chloride of potassium, sulphydric acid, free sulphur, and 
 a brown sulphur compound, apparently resulting from a secondary action (Kegnault) : 
 
 C 2 C1 + 2KHS = C 2 C1 4 + 2KC1 + EPS + S. 
 
 7. Heated in sealed tubes with 8 at. hydrate of potassium, it yields oxalate and chloride 
 of potassium : 
 
 C 2 C1 6 + 8KHO = C 2 K 2 4 + 6KC1 + 4H 2 ; 
 
 but the decomposition is very imperfect, even when the mixture is heated to between 
 210 and 220 C. for several days (G-euther, Ann. Ch. Pharm. Ix. 247). 8. Heated to 
 100 C. in sealed tubes with alcoholic potash, it yields the same products, together with 
 hydrogen gas and ethylene (Bert helot, Ann. Ch. Pharm. cix. 118). The principal re- 
 action is probably represented by the equation : 
 
 C 2 C1 6 + 7KHO + C 2 H 5 .K.O = C 8 K 2 4 + 6KC1 + 4H 2 + C 2 H 4 , 
 
 and the free hydrogen results from a secondary decomposition, a number of liquid 
 products and brown insoluble substances being formed at the same time. Trichloride 
 of carbon is not attacked by ammonia, nitric acid, or sulphuric acid. Boiling nitric 
 acid dissolves it, part separating on cooling, the rest on addition of water. In contact 
 with chlorine and water, it does not yield trichloracetic acid. 
 
 BICHLORIDE OF CARBON. C 2 C1 4 . Protochloride of Carbon, Perchlorethylene, Clilo- 
 rethose. Discovered and examined by Faraday (Phil. Trans. 1821, p. 47), further by 
 Regnault (Ann. Ch. Phys. [2] Ixx. 104 ; Ixxxi. 372). It is produced by the action of a 
 red heat on the trichloride or tetrachloride of carbon, either alone or in presence of 
 hydrogen (pp. 765, 766) ; by the action of nascent hydrogen on the trichloride at ordinary 
 temperatures ; also by that of alcoholic sulphydrate of potassium on the trichloride, and 
 of alcoholic potash on the tetrachloride (p. 765). 
 
 Preparation. 1. Vapour of trichloride of carbon is passed through a red-hot tube filled 
 with fragments of glass, whereupon a large quantity of chlorine is set free, and the di- 
 chloride passes over in the form of a liquid coloured yellow by chlorine. It is purified 
 by passing it several times through the red-hot tube, then shaking it up with mercury, 
 and rectifying at as low a temperature as possible (Faraday). 2. The trichloride is 
 added by small portions to an alcoholic solution of sulphydrate of potassium, and, as soon 
 as the evolution of sulphuretted hydrogen has ceased, the liquid is distilled, and the alco- 
 holic distillate diluted with water : the dichloride then separates in the form of a heavy 
 liquid: this process is easier than the preceding (Kegnault). 3. Trichloride of car- 
 bon is mixed with water and granulated zinc, and sulphuric acid added from time to 
 time with agitation, till all the trichloride is decomposed. On subsequently distilling 
 the liquid, dichloride of carbon passes over with the aqueous vapour. (Greuther, 
 Ann. Ch. Pharm. cvii. 212.) 
 
 Properties. Very mobile liquid, of specific gravity 1-619 at 20 C. (Kegnault), 
 1-612 at 10 (Greuther). Kefracting power = 1-4875 (Wollaston). It does not 
 conduct electricity. It remains liquid at 18 C. ; boils at 122 (Regnault), 116'7 
 (Greuther). Vapour-density, by experiment = 5'82, corresponding to 2 volumes. 
 
 [ x 0'0693 = 5 75. ] It is insoluble in water, acids, and aqueous al- 
 kalis, but dissolves in alcohol, ether, and oils, both fixed and volatile. 
 
 Decompositions. 1. At a red heat it is resolved into free chlorine and the proto- 
 chloride, C 2 C1 2 . 2. When its vapour is passed over red-hot baryta, vivid ignition 
 takes place, with formation of chloride of barium and carbonic anhydride, and separa- 
 tion of charcoal. 3. Heated for some time to 200 C., with 6 at. hydrate of potassium, 
 it is completely converted into oxalate and chloride of potassium, with evolution of 
 hydrogen gas (Greuther, Ann. Ch. Pharm. ex. 247) : 
 
 C 8 C1 4 + 6KHO = C 2 K 2 4 + 4KC1 + 2H 2 + H 2 . 
 
 4. It absorbs dry chlorine in sunshine, forming the trichloride, C'-'Cl 6 ; but if exposed 
 to an atmosphere of chlorine under a layer of water, it yields trichloracetic acid. 
 (Kolbe, Ann. Ch. Pharm. liv. 181) : 
 
 C 2 C1 4 + 2H-0 + Cl 2 = C 2 HC1 3 2 + 3HC1. 
 
 5. It absorbs bromine in sunshine, yielding chlorobromide of carbon, C 2 Cl'Br 2 . 
 
768 CARBON : DETECTION AND ESTIMATION. 
 
 PBOTOCHLOBIDE OF CARBON, C 2 C1 2 . Subchloride of Carbon, Julirfs Chloride of 
 Carbon. This compound was discovered in 1821, by Julin, a manufacturer of nitric 
 acid at Abo in Finland, who obtained it accidentally in distilling crude nitre with burnt 
 green vitriol in cast-iron retorts, the cast-iron probably furnishing the carbon, and the 
 crude nitre the chlorine (Ann. Ch. Phys. [2] xviii. 269). It was more exactly in- 
 vestigated by Phillips and Faraday (Phil. Trans. 1821), and afterwards by Keg- 
 nault (Ann. Ch. Phys. [2] Ixx. 104), who prepared it by passing vapour of chloroform 
 or of dichloride of carbon, through a strongly ignited porcelain tube filled with frag- 
 ments of porcelain, dissolving the crystalline product in ether, filtering, evaporating to 
 dryness, and subliming. In performing this process, care must be taken not to heat 
 the porcelain tube too strongly ; otherwise, no chloride of carbon will be obtained, but 
 only a deposit of charcoal. 
 
 Properties. Protochloride of carbon forms white, delicate needles, apparently four- 
 sided, having a silky lustre. It melts, boils, and sublimes between 175 and 200 C., 
 but may be sublimed without fusion at 120, the sublimate then consisting- of long 
 needles. It has a peculiar odour, something like that of spermaceti, but no taste. In 
 the cold it is almost inodorous. It is insoluble in water, but very soluble in alcohol ; 
 dissolves also in ether, and in hot oil of turpentine, whence it crystallises in needles 
 on cooling. 
 
 The alcoholic solution does not precipitate nitrate of silver. 
 
 The vapour passed through a red-hot porcelain tube filled with fragments of rock- 
 crystal, is resolved into chlorine and charcoal. The compound burns with bluish colour 
 in the flame of a candle, but ceases to burn when withdrawn. It is not decomposed 
 or dissolved by nitric, hydrochloric, or sulphuric acid, or by boiling potash. Chlorine 
 does not act upon it, even in sunshine. Potassium burns in its vapour with intense 
 ignition, forming chloride of potassium and depositing charcoal. 
 
 Berth elot regards this compound, not as C 2 C1 2 , but as C 10 C1 10 . The vapour-density 
 does not appear to have been determined. 
 
 C AKBOW, CHZiOROBROXKXDX: OP. C 2 Cl 4 Br 2 . Bromide of Perchorethylene, 
 Bromure de Chloroxethose. (Malaguti, Ann. Ch. Phys. [3] xvi. 14.) Dichloride of 
 carbon exposed to sunshine in contact with bromine solidifies in a few hours to a crys- 
 talline mass, which may be purified by repeated crystallisation from alcohol. The crys- 
 tals resemble those of C 2 C1 6 ; they have a specific gravity of 2-3 at 21 C., taste slightly 
 aromatic, begin to volatilise at 100, decompose at about 200 into bromine and the di- 
 chloride, and when treated with protosulphide of potassium are resolved into bromide 
 of potassium and dichloride of carbon : 
 
 C 2 Cl 4 Br 2 + K 2 S = C 2 C1 4 + 2KBr + S. 
 
 CARBON, DETECTION ANI> ESTIMATION OF. The methods of de- 
 tecting and estimating carbon and its compounds have been already described under the 
 head of ANALYSIS. 
 
 If the carbon is not already in the form of carbonic anhydride or a carbonate, it is 
 converted into carbonic anhydride by combustion, either in an atmosphere of oxygen or 
 with oxide of copper or chromate of lead, the amount of carbonic anhydride thereby pro- 
 duced being estimated by absorption in strong potash-ley (ANALYSIS, ORGANIC, pp. 225 
 238). This method serves for the estimation of carbon in cast-iron and other metallic 
 compounds, as well as in organic bodies. Gaseous carbon-compounds, such as carbonic 
 oxide and hydrocarbons, are converted into carbonic anhydride by explosion with ex-, 
 cess of oxygen, the amount of that compound produced being then determined by 
 absorption with potash. (ANALYSIS, VOLUMETRIC, OF GASES, pp. 286288.) 
 
 Carbonates are decomposed with dilute sulphuric or hydrochloric acid, and the car- 
 bonic anhydride thereby evolved is usually determined by loss (see ACIDIMETRY, p. 38, 
 and ALKALIMETRY, p. 149). The presence of carbonates in any mixture, solid or liquid, 
 is detected by the effervescence which ensues on addition of dilute sulphuric or hydro- 
 chloric acid. This effervescence may, however, arise from the escape of sulphydric 
 acid or sulphurous anhydride, if sulphides or sulphites are also present. These gases 
 are readily distinguished from carbonic anhydride by their peculiar odours ; sulphydric 
 acid also by its property of blackening lead-salts. To detect carbonic anhydride when 
 evolved together with one or both of these gases, the gaseous mixture is passed into 
 baryta-water. If a precipitate is formed, carbonic or sulphurous acid may be present 
 or both ; if the former alone, the precipitate will be completely soluble in hydrochloric 
 acid, after treatment with chlorine-water; but if sulphurous acid is also present, it will 
 be oxidised by the chlorine-water, and converted into sulphuric acid, which will then 
 form sulphate of barium, insoluble in hydrochloric acid. 
 
 The amount of carbonic anhydride in a gaseous mixture is ascertained directly by 
 absorption with potash, sulphurous anhydride or sulphydric acid, if present, having 
 been previously removed by absorption with peroxide of manganese (j, 282). 
 
CARBON: ESTIMATION. 769 
 
 Carbonic acid in solution, either free or combined, in a mineral water for example, 
 is estimated by adding ammonia and chloride of calcium, and leaving the liquid to 
 itself in a corked flask for several hours. The carbonic acid is thereby precipitated as 
 carbonate of calcium, containing 43*88 per cent. CO 2 . 
 
 To estimate the carbonic acid in the air, a large quantity of air, the volume being 
 measured by an aspirator (p. 427), is passed through a series of weighed potash-bulbs. 
 Another method is to shake up a quantity of air in a closed vessel of known capacity, 
 with an excess of lime-water of known strength, and then determine the quantity of 
 lime remaining uncombined by means of a standard solution of oxalic acid. This 
 method is easy of execution, and affords the means of quickly determining the varying 
 amount of carbonic acid in the several parts of an inhabited apartment at different 
 times. 
 
 Atomic Weight of Carbon. Three methods have been adopted for determining 
 the atomic weight of carbon : 1. From the quantity of carbonic anhydride produced 
 by the combustion of a given weight of carbon. 2. By comparing the weights of equal 
 volumes of carbonic anhydride and oxygen, it being supposed that carbonic anhydride 
 contains its own volume of oxygen. 3. From the weight of metallic silver obtained 
 by the combustion of organic silver-salts. 
 
 Of these methods the first is considered the most trustworthy. The amount of car- 
 bonic anhydride produced by the combustion of carbon was determined with a very 
 near approximation to the truth by Lavoisier in 1775, afterwards with more or less 
 accuracy by G-uyton-Morveau (1785), Clement and Desormes (1802), Allen and Pepys 
 (1807), and Saussure (1809); but the most exact determinations are those made by 
 Dumas and Stas (Ann. Ch. Phys. [3] i. 1), and by Erdmann and Marchand 
 (J. pr. Chem. xxiii. 159). These chemists burned weighed quantities of diamond or 
 graphite with oxide of copper and oxygen gas, and weighed the carbonic anhydride 
 taken up by the potash-apparatus, after it had been freed from a very small quantity 
 of admixed water by passing over chloride of calcium or sulphuric acid. The small 
 quantity of residual ash. was deducted from the weight of the carbon employed, and 
 the quantity of water produced in the combustion likewise taken into account. 
 
 In this manner the quantity of carbon which combines with 200 pts. of oxygen to 
 form carbonic anhydride was found by Dumas and Stas, in fourteen experiments, to 
 vary only between the limits 74*87 and 75'12, the mean result being 75*005, with a pro- 
 bable error of + 0*013. Erdmann and Marchand, in nine experiments similarly con- 
 ducted, obtained numbers varying between 74*84 and 75*19, the mean being 75*028. Now 
 since, of the two oxides of carbon, carbonic anhydride contains, with the same quantity 
 of carbon, twice as much oxygen as carbonic oxide, these compounds maybe represented 
 by the formulae CO 2 and CO, a view of their constitution, which is likewise in accord- 
 ance with that of the other compounds of carbon. Hence, from the above-mentioned 
 results respecting the composition of carbonic anhydride, it follows that if the atomic 
 weight of oxygen = 100, that of carbon will be 75, and on the hydrogen scale : 
 
 If 0=8, C = 6 
 
 and if = 16, C = 12. 
 
 The reason for adopting the numbers in the last line are fully detailed in the article 
 ATOMIC WEIGHTS (pp. 459 462). 
 
 The second method of determining the atomic weight of carbon was first adopted by 
 Berzelius and Dulong in 1819. From specific gravity determinations then made it 
 was concluded that equal volumes of carbonic anhydride and oxygen weighed 1'5425 
 and 1*1026 respectively ; and assuming that carbonic anhydride contained its own 
 volume of oxygen, the difference of the two numbers gave the weight of the carbon in 
 the same volume, whence it was calculated that the atomic weight of carbon on the 
 oxygen scale (0 = 100) was 76*528, which number was adopted as correct for twenty 
 years. In 1841, Wrede, following the same method, but taking into account the more 
 exact coefficients of expansion of the gases determined by Budberg, Magnus, and 
 Regnault, obtained the number 75*12. Determinations not much differing from this 
 were made in like manner by other experimenters ; but the method is not capable of 
 yielding very exact results, because the alterations of volume sustained by oxygen 
 and carbonic anhydride for equal variations of temperature and pressure are not equal, 
 and consequently the assumption that oxygen, in being converted into carbonic anhy- 
 dride, undergoes no change of volume, cannot be true for all temperatures. 
 
 The third method, founded on the analysis of the silver-salts of organic acids, was 
 adopted by Lie big and Eedtenbacher (Ann. Ch. Pharm. xxxviii. 116). Assuming 
 Ag = 1351 and H = 12*48 (0 = 100), these chemists obtained as the mean result of 
 their analyses, C = 75*854. The more exact determinations since made of the atomic 
 weight of silver would lead to a slight alteration in this result. Strecker, from the 
 
 VOL. I. 3D 
 
770 CARBON: OXIDES. 
 
 same experiments, and without assuming the atomic weights of silver as previously 
 known, calculated the atomic weight of carbon as = 75'415 ; but this method, as well 
 as the second, is not considered so trustworthy as the first, the result of which, ob- 
 tained by Dumas and Stas is now universally adopted. 
 
 CARBON", IODIDE OP. No compound of carbon and iodine has yet been ob- 
 tained, lodoform, CHI 3 , was formerly sxipposed to be an iodide of carbon, the hydrogen 
 contained in it having been overlooked. (Grm. vii. 335.) 
 
 CARBON, NITRIDE OF. Only one compound of carbon and nitrogen is 
 known with certainty, viz. CYANOGEN, CN (q. v.) Many cyanogen-compounds yield by 
 calcination a residue called me Hone, which Liebig regards as a nitride of carbon con- 
 taining C 3 N 4 . It does not, however, appear to have been obtained quite free from 
 hydrogen (see MELLONE and MEIXONTDES). According to Thaulow, a peculiar nitride 
 of carbon, isomeric, but not identical with cyanogen, is obtained by ignition of cyanide 
 of silver (see CARBAZOTE, p. 757). 
 
 CARBON*, OXIDES OF. Two oxides of carbon are known, the protoxide CO, 
 and the dioxide, or carbonic anhydride, CO 2 , commonly called carbonic acid. Both are 
 produced by the direct combination of carbon and oxygen ; the former is known only 
 in the gaseous state : the latter is gaseous at ordinary temperatures. 
 
 DIOXIDE OF CARBON. CARBONIC ANHYDRIDE, CO 2 . Anhydrous Carbonic 
 acid, Fixed air, Mephitic air, kohlcnsaurcs gas, Kohlens'dure, Gas sylvestre, Spiritus 
 sylvestris. The evolution of this gas in the burning of lime and in fermentation, was 
 known to Paracelsus and Van Helmont, the latter of whom gave it the name of gas 
 sylvestre; its properties were afterwards investigated by Hales, Black, Cavendish, 
 Priestley, and Bergmann, but its true composition was first demonstrated by Lavoisier, 
 who showed that it was a compound of carbon and oxygen, containing 28 per cent, 
 carbon and 72 oxygen, numbers approaching very nearly to the proportions now received 
 as correct, viz. 27'27 carbon to 7273 oxygen (p. 769). 
 
 Carbonic anhydride is formed by the combustion of carbon in oxygen gas, or in the 
 air. It is a constant product of the ordinary processes of combustion, inasmuch as all 
 substances used for fuel, such as wood, coal, oil, v, r ax, tallow, &c. contain carbon. It is 
 likewise formed by the respiration of animals, in various processes of fermentation, as 
 in the preparation of wine and beer, and by the decay of animal and vegetable sub- 
 stances. It issues from fissures in the ground, in various localities, chiefly in volcanic 
 districts, and is ejected in enormous quantities from the craters of active volcanos. 
 From all these sources it is continually being poured into the atmosphere, of which it 
 therefore forms a constant constituent : the average amount of it contained in the air 
 in the open country, is 4 volumes in 10,000; in the air of crowded towns, it is often 
 much greater (p. 437). It exists also in larger proportion at the bottom of wells, mines, 
 quarries, and caverns, especially in limestone districts, where it is evolved from 
 fissures and does not readily escape, in consequence of its greater density. Carbonic 
 anhydride (or acid), exists also in solution in all natural waters, some, as those of 
 Seltz, Vichy, and Spa, containing it in such quantity as to give them an effervescing 
 character. Lastly, it is produced by the decomposition of carbonates, either by heat or 
 by the action of the stronger acids, and is a frequent product of the decomposition of 
 organic bodies at high temperatures. 
 
 Preparation. The easiest way of obtaining the gas is to decompose chalk, or marble, 
 with hydrochloric acid, in an ordinary generating vessel, provided with a gas-delivery 
 tube: 
 
 Ca 8 CO + 2HC1 = 2CaCl + CO 2 + H 2 0. 
 
 Dilute sulphuric acid may also be used, but it is less convenient, as the sulphate of 
 calcium produced forms a hard mass in the vessel, which is difficult to extract, whereas 
 chloride of calcium is easily soluble : moreover, the chloride is more useful as a resi- 
 dual product. The gas may be received over water, or, as it is very heavy, it may bo 
 collected by simple displacement of the air, the delivery-tube being bent vertically 
 downwards, so as to reach to the bottom of the receiver. This is also the most 
 convenient mode of collection when the gas is required dry, a desiccating tube contain- 
 ing dry chloride of calcium or pumice-stone soaked in oil of vitriol, being interposed 
 between the generator and receiver. On the large scale, carbonic anhydride may be 
 obtained by heating chalk or marble to redness, in an iron or earthen retort. 
 
 Properties. Carbonic anhydride is, at ordinary temperatures and pressures, a colour- 
 less gas, but may be liquefied by cold or pressure (p. 771). Its specific gravity in the 
 gaseous state isl-5241(Regnault), being rather more than 1| times that of air. In 
 consequence of this great density, it may be poured from one vessel to another like a 
 liquid, and often collects at the bottom of wells, mines, and caverns, as in the Grotto 
 del Cane near Naples, the atmosphere of which, within about a foot of the ground, is 
 highly charged with the gas, while the uppc-r partis comparatively free. 
 
 From the experiments of Kegnault, it appears that the density of carbonic anhydride 
 
CARBON: OXIDES. 771 
 
 does not vary in the same proportion as the pressure, excepting within narrow limits : 
 under a pressure of several atmospheres, the deviation from this law is very perceptible. 
 The coefficient of expansion by heat between and 100 C. is 0-3719 (Kegnault) ; 
 0-366087 (Magnus); refracting power = 1*526 (Dulong). 
 
 Carbonic anhydride does not affect the colour of litmus-paper, when both are quite 
 dry ; but if moisture is present, the blue colour of the paper changes to wine-red, 
 like that produced by boric acid : on exposure to the air, however, the redness disap- 
 pears, in consequence of the escape of the gas. Lime-water introduced into the gas is 
 immediately rendered turbid, in consequence of the formation of neutral carbonate of 
 calcium, but if an excess of the gas is present, the liquid becomes clear again after a 
 while, especially if shaken, an acid carbonate being then formed, which is soluble in 
 water. Solution of potash, or a lump of moist solid potash, introduced into the gas 
 standing over mercury, rapidly absorbs it. It dissolves in about its own volume of 
 water at ordinary temperatures, and in less than of its volume of alcohol. 
 
 Carbonic anhydride is irrespirable ; animals immersed in it soon die, not only from 
 want of oxygen, but in consequence of a direct poisonous action, violent spasms being 
 sometimes produced, sometimes complete atony of the cerebral faculties. Mixed with 
 air, as it escapes from effervescing liquids, it produces a pungent sensation in the re- 
 spiratory organs, but it cannot be said to have any decided odour. It is incombustible, 
 and immediately extinguishes a burning taper, also the flame of sulphur or phosphorus : 
 but potassium heated to redness in the dry gas, decomposes it completely, burning with 
 a red light, and producing a deposit of charcoal mixed with carbonate of potassium. 
 Sodium decomposes it in like manner, but without becoming red-hot. Phosphorus and 
 boron, in presence of an alkali, likewise abstract all the oxygen at a red heat. Hy- 
 drogen, charcoal, iron, and zinc, at a red heat, abstract half the oxygen, converting 
 the carbonic anhydride into carbonic oxide. It is also resolved into carbonic oxide and 
 oxygen by the passage of electric sparks, if hydrogen gas, mercury, or some other 
 metal is present to take up the oxygen ; otherwise, the spark immediately causes the 
 gases to recombine. Growing plants, or the leaves and other green parts separated 
 from the plant, but still in the fresh state, decompose carbonic anhydride completely 
 under the influence of daylight, and more rapidly in direct sunshine, abstracting the 
 whole of the carbon, and setting the oxygen free. If some fresh leaves of any plant 
 be placed in an inverted receiver, filled with water containing carbonic acid, and stand- 
 ing over water, and the whole be exposed to the sun, a considerable quantity of 
 oxygen gas will collect at the top of the receiver in a few hours. This action of 
 growing plants is the chief cause which prevents the continual accumulation of car- 
 bonic anhydride in the atmosphere, and keeps the proportion of it nearly constant. 
 (See ATMOSPHERE, p. 438.) 
 
 Respecting the mode of determining the composition of carbonic anhydride, see 
 p. 769. Its density corresponds to 2 volumes of vapour : 
 
 12 + ^' 16 x 0-0693 = 22 x 0-0693 = 1'5246 
 
 and at pressures and temperatures considerably above its liquefying point, it contains 
 a volume of oxygen exactly equal to its own. 
 
 Liquid Carbonic Anhydride. Carbonic anhydride passes to the liquid state at C. 
 under a pressure of 36 atmospheres. Faraday effected the liquefaction by evolving the 
 gas from carbonate of ammonia, by the action of sulphuric acid in a sealed tube (see 
 GASES, CONDENSATION OF), but the method is dangerous, and yields but a small quantity. 
 The liquid acid is however obtained safely and in large quantity, by the method of 
 Thilorier (Ann. Ch. Pharm. xxx. 122). The apparatus consists of two very strong 
 cylinders, capable of holding 6 litres or pints, made of cast-iron, or better, of lead 
 sheathed with copper, and strengthened with a wrought-iron armature ; they rest bj 
 two pins placed at the middle of their length on cast-iron supports, so that they may 
 be placed either vertically or horizontally, and swung backwards and forwards. Into 
 one of these cylinders is introduced 1800 grammes of acid carbonate of sodium, and 
 4 litres of water (or 4 Ibs. of the soda-salt, and 7 pints of water), and a copper tube 
 containing 1000 grammes (or 2| Ibs.) of strong sulphuric acid, is likewise introduced 
 in a vertical position. The cylinder is then tightly closed by a cock of peculiar con- 
 struction, and swung to and fro, to cause the acid to mix gradually with the carbonate. 
 The gas is then evolved, and not being able to escape, becomes so much condensed that 
 it passes to the liquid state. This part of the operation requires care, as, if the mix- 
 ture be made too rapidly, great heat will be evolved, and the tension of the gas 
 enormously increased. A fatal accident happened in Paris from this cause. When 
 the action is supposed to be complete, the generating cylinder is made to communicate, 
 by means of a copper tube, with the second cylinder, which is placed horizontally, and 
 provided with a stopcock like the first. This cylinder being slightly cooled, the car- 
 
 3 D 2 
 
772 
 
 CARBON: OXIDES. 
 
 bonic anhydride distils over from the first, which is still warm, and condenses in the 
 liquid state. After about a minute the cocks are closed, the cylinders separated, the 
 charge in the first renewed ; and this series of operations is repeated several times, till 
 the second cylinder is about two-thirds filled with liquid carbonic anhydride. 
 
 Liquid carbonic anhydride is colourless and very soluble in alcohol, ether, and vola- 
 tile oils, but does not mix with water. Specific gravity 0'90 at 20 C. ; 0-83 at 
 C.; 0-60 at + 30 C. (Thilorier). Its tension at different temperatures is shown 
 in the following table. 
 
 
 Tension in Atmospheres. 
 
 
 Tension in Atmospheres. 
 
 
 ^~ 
 
 Mareska 
 
 
 
 Mareska 
 
 Temp. C. 
 
 Faraday. 
 
 and 
 Donny. 
 
 Temp. C. 
 
 Faraday. 
 
 and 
 Donny. 
 
 59-40 
 
 4-6 
 
 
 -5-00 
 
 33-1 
 
 36 
 
 48-8 
 
 77 
 
 
 O'O 
 
 38-5 
 
 42 
 
 36-6 
 
 12-5 
 
 
 +6-3 
 
 
 46 
 
 30.5 
 
 15-4 
 
 
 10-0 
 
 
 52 
 
 26-1 
 
 17-8 
 
 
 15-5 
 
 
 57 
 
 200 
 
 21-5 
 
 23-6 
 
 J9-0 
 
 
 63 
 
 15-0 
 
 24-7 
 
 25-3 
 
 23-5 
 
 
 68 
 
 12-2 
 
 26-8 
 
 
 270 
 
 
 74 
 
 10-0 
 
 
 27-5 
 
 307 
 
 
 80 
 
 94 
 
 29-1 
 
 
 34-5 
 
 
 
 Solid Carbonic Anhydride. When the liquid anhydride is suddenly relieved from 
 the pressure under which alone it can exist, part of it flashes instantly into vapour, 
 and in so doing produces so great a degree of cold, that the remaining portion of the liquid 
 solidifies. To obtain the solid anhydride, the receiver containing the liquid is provided 
 with a tube passing through its side, and reaching nearly to the opposite side, so that 
 when the cylinder is set horizontally, this tube dips into the liquid. On opening a 
 stopcock provided for the purpose, a quantity of the liquid is forced out by the pressure 
 of the gas above it, and forms a white cloud of the solid anhydride, as it issues into 
 the air. By causing this jet of vapour to pass into a cylindrical metal box, having 
 within it an inclined metal tongue, against which the jet of liquid and vapour im- 
 pinges, and is thus made to circulate within the box for some little time before it 
 finally escapes, a considerable quantity of the solid anhydride may be collected in the 
 form of a white flocculent mass like snow. 
 
 Solid carbonic anhydride may be left exposed to the air for some little time without 
 evaporating, because, like all flocculent substances, it conducts heat but slowly. Its 
 tension is 1-14 atmospheres at - 99-4 C. ; T36 at -77'2; 2'28 at -70'5; 3-6 at 
 63-2; 4-6 at 59'4; 5'33 at 57'0 (Faraday). An air or spirit thermometer 
 immersed in it sinks to 78 C. Notwithstanding this low temperature, the solid 
 substance may be placed on the hand without occasioning a very acute sensation of 
 co'd, because it does not come into close contact with the skin, being separated from 
 it by a film of vapour ; but if pressed between the fingers, it produces a very painful 
 sensation, and raises a blister like a burn. By mixing it with ether, its heat-conduct- 
 ing power is greatly increased ; it therefore evaporates more quickly, and produces 
 much more powerful frigorific effects. Mercury poured into it solidifies instantly to a 
 mass like lead. The cold which it produces is sufficient to liquefy sulphydric acid, 
 chlorine, nitrous oxide, and several other gases. The intensity of the cold may be still 
 further increased by placing the mixture under an exhausted receiver. The tempe- 
 rature then sinks to a degree at which the liquid anhydride is not more volatile than 
 water at 30 C., and alcohol assumes the consistence of a thick oil, but does not solidify. 
 By exposing to this bath, tubes of glass or copper in which gases have been compressed 
 by a forcing pump to 40 atmospheres, Faraday has succeeded in liquefying all the 
 known gases, excepting oxygen, hydrogen, nitric oxide, carbonic oxide, and marsh-gas, 
 and in solidifying a considerable number of them. Carbonic anhydride itself exposed 
 to this temperature and pressure, is reduced to a vitreous transparent mass. 
 
 Carbonic Acid. Gaseous carbonic anhydride dissolves in about its own volume 
 of water at ordinary temperatures, forming a solution of specific gravity I'OOIS. It 
 has a sharp and slightly acid taste, turns the blue colour of litmus to wine-red, partially 
 neutralises alkalis, and dissolves the carbonates of barium, strontium, calcium, mag- 
 nesium, &c. It, therefore, possesses acid properties, and from the composition of the 
 carbonates, we may infer that it contains an acid of the composition H 2 C0 3 . But this 
 acid cannot be isolated, as heat, diminished pressure, or congelation immediately re- 
 solves it into water and carbonic anhydride. In short, carbonic acid as a definite 
 compound cannot be said to be known. 
 
CARBON: OXIDES. 773 
 
 The volume of carbonic anhydride dissolved by water at a given temperature, is 
 nearly the same under all pressures ; consequently the weight of the gas absorbed in- 
 creases in nearly the same proportion as the pressure. This rule must not, however, 
 be understood as strictly true, for Eegnault has shown that the volume of carbonic 
 anhydride does not vary exactly in the inverse ratio of the pressure. 
 
 Under a given pressure, the volume of gas absorbed diminishes as the temperature 
 rises. At the boiling heat, the whole of the gas is driven off; hence carbonic acid 
 water holding an earthy carbonate in solution deposits it when the liquid is boiled. 
 This is the cause of the furring of kettles, boilers, &c., in which spring or river-water 
 containing carbonate of calcium dissolved in this manner, is boiled. 
 
 The coefficients of absorption of carbonic anhydride, that is to say the volumes 
 (reduced to C. and 0760 met.) which 1 vol. of water absorbs under the pressure of 
 0760 met. and at various temperatures, are as follows: 
 
 Vol. of Gas Vol. of Gas 
 
 Temp. absorbed. Temp. absorbed. 
 
 0C. . . . 17697 12 C. . . . 1-1018 
 
 2 ... 1-6481 H ... 1-0321 
 
 4 ... 1-5126 16 ... 0-9753 
 
 6 ... 1-3901 18 ... 0-9318 
 
 8 ... 1-28C9 20 ... 0-9013 
 
 10 ... 1-1847 
 
 (Bunsen's Gasometry. See also the article GASES, ABSORPTION OF.) 
 
 Water which has been saturated with carbonic acid under pressure, gives it up with 
 brisk effervescence as soon as the pressure is removed. The various kinds of aerated 
 water, soda-water, effervescing lemonade, &c., consist of water impregnated by mecha- 
 nical pressure with large quantities of carbonic acid, and flavoured with various saline 
 and other ingredients. (For a description and figure of Tylor's soda-water machine, 
 see Ure's Dictionary of Arts, Manufactures and Mines, iv. 728.) Champagne and 
 other effervescing wines and bottled beer likewise owe their sparkling properties to 
 the presence of this gas ; but in these liquids the carbonic acid is produced by the 
 fermentation itself, the wine or beer being bottled before the fermentation is complete, 
 whereby a considerable quantity of the gas, which would otherwise escape into the air, 
 is retained. 
 
 For the behaviour of aqueous carbonic acid to bases, see CARBONATES. 
 PROTOXIDE OF CARBON. CARBONIC OXIDE. CO. This compound, which is 
 known only in the gaseous state, was discovered towards the end of the last century by 
 Lassonne and by Priestley ; but its true nature was first recognised some years after- 
 wards by Woodhouse (Gilbert's Annalen, ix. 423). It is produced : 1. By the oxi- 
 dation of carbon at very high temperatures,when the supply of oxygen is not sufficient 
 for the complete conversion of the carbon into carbonic anhydride (p. 763). 2. When 
 carbonic anhydride is exposed to a red heat in contact with hydrogen, carbon, metals, 
 or other bodies which can abstract part of the oxygen : hence it is always produced in 
 charcoal or coke fires, when the draught of air has to pass upwards through a con- 
 siderable mass of red-hot fuel, and is the cause of the blue flame almost always seen 
 on the top of such fires. 3. It is also formed, together with hydrogen and carbonic 
 anhydride, when vapour of water is passed over red-hot coke or charcoal. A sample 
 of the gaseous mixture thus formed was found by Bunsen to contain 56-03 volumes per 
 cent, of hydrogen, 29-15 carbonic oxide, 14'65 carbonic anhydride, and 0'17 carburetted 
 hydrogen. 4. Carbonic oxide is produced, either alone or together with carbonic 
 anhydride, in the reduction of metallic oxides by carbon at a strong red heat. The 
 gas evolved from iron blast-furnaces contains from 25 to 32 per cent., that from copper- 
 refining furnaces from 13 to 19 per cent, carbonic oxide (Bunsen, Pogg. Ann. xlvi. 
 193; 1. 81). 5. In the dry distillation of many organic compounds. 6. In the de~ 
 composition of oxalic acid and formic acid by strong sulphuric acid : 
 
 C 2 H 2 4 = CO + CO 2 + H 2 
 
 Oxalic 
 acid. 
 
 CH 2 2 = CO + H 2 
 Formic 
 acid. 
 
 7. In the decomposition of crystallised ferrocyanide of potassium by sulphuric acid 
 (Fownes): 
 
 2K 2 FeC 3 N 3 .3H 2 -- 6H 2 S0 4 + 3H 2 = 6CO + 3(NH 4 ) 2 SO* + 2K 2 S0 4 + Fe'SO* 
 
 Crystallised ferro- Sulphate of Sulphate Ferrous 
 
 cyanide of ammonium. ofpotas- sulphate, 
 
 potassium. sium. 
 
 3D 3 
 
774 CARBON: OXYCHLORIDE. 
 
 Preparation. 1. By heating to redness in a gun-barrel fitted with a gas-delivery 
 tube, a mixture of oxide of iron, zinc, lead, or copper with charcoal or graphite ; or of 
 an alkaline or earthy carbonate (chalk for example) with graphite, charcoal, or iron 
 filings ; or by passing carbonic anhydride repeatedly over red-hot iron or charcoal. 
 By either of these methods, carbonic oxide is obtained mixed with carbonic anhydride, 
 from which it may be freed by passing the gas through milk of lime or strong potash ; 
 it may then be collected over water. The charcoal used must be previously well ignited 
 to free it from moisture and absorbed gases. 2. By heating in a flask a mixture of 
 oxalic acid, or an oxalate, or a formate, with excess of strong sulphuric acid, and remov- 
 ing the carbonic anhydride evolved when oxalic acid or an oxalate is used, as before. 
 3. "When crystallised ferrocyanide of potassium, in the state of powder, is heated in a 
 flask with eight or ten times its volume of sulphuric acid, carbonic oxide is evolved 
 quite free from carbonic anhydride, and mixed only with a small quantity of vapour 
 of hydrocyanic acid, resulting from another reaction which takes place at the same 
 time, if the quantity of water present is more than sufficient for the above decomposi- 
 tion (see FERROCYANEDES). This is the most convenient mode of preparing carbonic 
 oxide. Care must, however, be taken not to raise the heat higher than is necessary 
 for the complete liquefaction of the mixture ; for at that point the evolution of carbonic 
 oxide ceases, and if the heating be continued, the excess of sulphuric acid acts on the 
 ferrous sulphate produced, converting it into ferric sulphate, and being itself reduced 
 to sulphurous anhydride, which escapes as gas and mixes with the carbonic oxide. 
 
 Properties. Carbonic oxide is a colourless gas of specific gravity 0*96799 (Wr ede) ; 
 its molecule CO therefore occupies two volumes : 
 
 12 * 16 x 0-0693 = 14 x 0-0693 = 0*9702. 
 
 It is perfectly neutral to vegetable colours, and very sparingly soluble in water, 
 which, according to Bunsen, dissolves only 0'024 or about ^ of its bulk at 15 C. It 
 is a very poisonous gas, acting chiefly on the nervous system, causing giddiness when 
 inhaled, sometimes also acute pain in various parts of the body, and after a while 
 complete asphyxia. According to Leblanc (Ann. Ch. Phys. [3] v. 223), it is to 
 this gas that the suffocating quality of air in which charcoal has been burnt is chiefly 
 due. 
 
 Carbonic oxide does not support the combustion of bodies which burn in oxygon, 
 but in contact with the air it takes fire on the approach of a burning body, and burns 
 with a blue flame, producing carbonic anhydride. Mixed with excess of oxygen, it 
 may be exploded by the electric spark, 2 vols. of it then uniting with 1 vol. oxygen 
 and producing 2 vol. carbonic anhydride CO 2 . Now as 2 vols. CO 2 contain 2 vols. 
 oxygen, it follows that 1 vol. oxygen must have been derived from the carbonic oxide. 
 Hence carbonic oxide contains half its own volume of oxygen. Now the weight of 
 2 vols. carbonic oxide, compared with hydrogen, is 28, which, diminished by 16, the 
 weight of 1 vol. oxygen, leaves 12 for the weight of 1 atom of carbon. Hence in carbonic 
 oxide the same weight of carbon is united with exactly half as much oxygen as in 
 carbonic anhydride. 
 
 The combustion of carbonic oxide may be brought about by contact with platinum. 
 A wire or foil of the metal requires to be heated to 300 C. to induce the combustion : 
 spongy platinum acts at ordinary temperatures, without becoming sensibly heated ; 
 but platinum-black introduced into the mixture of carbonic oxide and oxygen becomes 
 red-hot and produces explosion. 
 
 Carbonic oxide reduces certain metallic oxides at a red heat, viz. the oxides of copper, 
 lead, tin, iron, &c. It plays indeed an important part in the smelting of many metals, 
 especially of iron. 
 
 Carbonic oxide is rapidly absorbed by a solution of cuprous chloride in hydrochloric 
 acid, also by ammonical solutions of cuprous salts. This reaction affords an excellent 
 method of removing carbonic oxide from a gaseous mixture (p. 283). It reduces 
 gold from the neutral solution of its chloride without the aid of heat. 
 
 Carbonic oxide unites directly with chlorine, forming oxy chloride of carbon or phos- 
 gene gas ; also with potassium. (See POTASSIUM.) 
 
 It is absorbed by hot hydrate of potassium, yielding formate of potassium, 
 CO + KHO = CHKO 2 . (Berth elot, Ann. Ch. Pharm. xcvii. 125.) 
 
 CARBON, OXYCHXiORXDX: OP, COC1 2 or Chloride of Carbonyl (CO)".C1 2 . 
 Chlorocarbonic oxide. Chlorocarbonic acid. Phosgene. This compound was discovered 
 by J. Davy (Phil. Trans. 1812, p. 144), who obtained it by exposing to the sun's rays, 
 a mixture of equal volumes of chlorine and carbonic oxide. The mixture gradually 
 becomes colourless and contracts to half its original volume. The same action takes 
 
CARBON: SULPHIDES. 775 
 
 place slowly in diffused daylight ; none whatever in the dark. The name phosgene 
 originally given to the gas signifies a compound formed by light. 
 
 Oxychloride of carbon may be more conveniently prepared by passing carbonic 
 oxide into boiling pentachloride of antimony, that compound being at the same time 
 reduced to trichloride. The gas must be received over mercury, as water decomposes 
 it (Hofmann, Ann. Ch. Pharm. Ixx. 139). It is likewise produced when carbonic 
 oxide is passed over red-hot chloride of lead or chloride of silver, and in the following 
 decompositions of organic bodies : 
 
 a. By the dry distillation of trichloracetates: 
 
 C 2 C1 3 M0 2 = CQC1 2 + CO + MCI. 
 
 b. By the dry distillation of certain perchlorinated methylic ethers, e. g. of \hefor- 
 mate,C-CVO* = 2COCP ; and of the oxalate, C 4 C1 6 4 = COC1 2 + 300. 
 
 c. By the action of a large excess of strong sulphuric acid on the so-called sulphite 
 of tetrachloride of carbon (p. 766) : 
 
 CCl'SO 2 + H 2 = COC1 2 + 2HC1 + SO 2 . 
 
 Oxychloride of carbon is a colourless gas having a suffocating and tear-exciting 
 odour. Its specific gravity is 3-6808 (Davy), 3 ! 4249 (Thomson); calculated for a 
 condensation to two volumes, it is 
 
 x 0-0693 = 3-430. 
 
 Its refracting power is 3*936. It reddens moistened litmiis-paper ; does not fume 
 in the air. 
 
 Oxychloride of carbon is decomposed by water, yielding carbonic anhydride and 
 hydrochloric acid : 
 
 COC1 2 + H 8 = CO 2 + 2HC1. 
 
 When mixed with an equal volume of hydrogen and half its volume of oxygen, it 
 explodes violently on the passage of an electric spark, yielding the same products. 
 Mixed with oxygen or hydrogen alone, it is not exploded by the electric spark. 
 
 Arsenic and antimony heated in the gas take up the chlorine, and leave carbonic oxido 
 equal in volume to the original gas. Many metallic oxides, oxide of zinc, for example, 
 decompose it with the aid of heat, forming a chloride of the metal and carbonic an- 
 hydride equal in volume to the original gas. Trioxide of antimony produces tri- 
 chloride and pentoxide or tetroxide of antimony, leaving carbonic oxide. 
 
 By alcohols it is converted into chlorocarbonic ethers, e. g. : 
 
 ii (PI P2TT5) /TTlY 
 
 co cJ + H - ( o& 
 
 a. 
 
 With ammonia gas, Oxychloride of carbon produces carbamide (p. 752) and chloridf 
 of ammonium. With phenylamine and many other organic bases, it reacts in like man- 
 ner, forming substitution-derivatives of carbamide. 
 
 CARBON 1 , SULPHIDES OP. Only one of these compounds is known with 
 certainty, viz. the disulphide corresponding to carbonic anhydride. The formation of 
 a protosulphide, analogous to carbonic oxide, was announced, in 1857, by Baudrimont, 
 but his statements have not been confirmed. (See page 777.) 
 
 DISULPHIDE OF CAB BON. CS 2 . Bisulphide of Carbon, Sulphocarbonic Acid. 
 (Lampadius, Gehlen's N. allg. Journ. d. Chem. ii. 192; Clement and Desormes, 
 Ann. Chim. xlii. 121; Vauquelin and Kobiquet, ibid. Ixi. 145; Berthollet, 
 Thenard, and Vauquelin, ibid. Ixxii. 252; Berzelius andMarcet, Schw. J. ix. 
 284; Berzelius, Gilb. Ann. xlviii. 177; Pogg. Ann. vi. 144; Zeise, Schw. J. xxvi. 
 1; xli. 98, 170; xliii. 160; Couerbe, Ann. Ch. Phys. [2] Ixi. 225; Kolbe, Ann. Ch. 
 Pharm. xlv. 53 ; xlix. 143 ; Pelouze and Fremy, Traite de Chimie, 4 me M. i. 923). 
 This compound, which was discovered by Lampadius in 1796, is produced by the 
 direct combination of sulphur and carbon at high temperatures, and in the decomposi- 
 tion of many organic compounds. Sulphur and carbon do not combine when simply 
 heated together in the solid state, because the sulphur volatilises before the requisite 
 temperature is attained ; but if charcoal be heated to redness and sulphur- vapour 
 passed over it, the carbon burns in that vapour, forming CS 2 . 
 
 For preparing small quantities of the disulphide, a porcelain tube is filled with frag- 
 ments of charcoal, and inserted in an inclined position through a furnace having holes 
 in its sides. The upper extremity of the tube is closed with a cork, and the lower is 
 connected by a bent glass tube, with a bottle containing water, the lower end of the bent 
 tube passing through the cork and dipping just below the surface of the water. When 
 
 3 r> 4 
 
776 CARBON: SULPHIDES. 
 
 the charcoal is red-hot, the upper end of the tube is opened and a piece of sulphur put 
 in the sulphur melts and runs down to the lower part of the tube, where it volatilises 
 and combines with the carbon, forming disulphide of carbon, which, passes off in 
 vapour and condenses in the liquid form at the bottom of the water. For larger quan- 
 tities, a tubulated earthen retort is used, having a porcelain tube passing through the 
 tubulus, and reaching nearly to .the bottom. The retort is filled with charcoal, heated to 
 redness in a furnace, and bits of sulphur dropt in through the tube. The neck of the 
 retort is connected with a condensing tube kept cold by a stream of water, and passing 
 into a receiver containing cold water as above described. The sulphide of carbon which 
 collects at the bottom of the water is not pure, but contains excess of sulphur. It is 
 purified by distillation at the heat of the' water-bath, the sulphide of carbon then 
 volatilising and the sulphur remaining behind. 
 
 Properties. Disulphide of carbon is a colourless, very mobile 1 , strongly refracting 
 liquid, having a faint and peculiarly unpleasant odour. Its refracting power is 1-645. 
 Specific gravity 1'293 at C., and 1-271 at 15. Boils at 46-6 under ordinary pres- 
 sure, and evaporates quickly at ordinary temperatures, producing great cold. Vapour- 
 
 , 12 + 2 32 \ 
 
 density = 2'67, corresponding to 2 vols. ( ^~ 1 - x 0-0623 = 2-63 J. It is inso- 
 luble in water, to which, however, it imparts its odour. Alcohol and ether mix with it 
 in all proportions. It dissolves sulphur, phosphorus,^ and iodine; sulphur and phos- 
 phorus separate from it by spontaneous evaporation in well defined crystals. It dis- 
 solves camphor and mixes easily with oils, both fixed and volatile. 
 
 Decompositions. 1. Disulphide of carbon is very inflammable, and burns with a 
 blue flame, producing sulphurous and carbonic anhydrides. 2. The vapour passed over 
 various metallic oxides at a red heat, yields the same gaseous products, together with a 
 metallic sulphide ; the sulphides thus formed are generally crystallised, and resemble 
 those found in nature. Sulphide of carbon is indeed one of the most powerful sul- 
 phurising agents known, affording the means of producing several metallic sulphidea 
 not otherwise obtainable (Fremy). It likewise converts oxides into sulphides when 
 heated with them in sealed tubes ; with water at 150 J C. it yields carbonic anhydride 
 and sulphydric acid (Schlagdenhauf fen, J. Pharm. [3] xxix. 401). 3. The vapour 
 is strongly attacked by nitric acid, yielding sulphuric acid and nitrous vapours. 
 4. Sulphide of carbon heated with chlorates or hypochloritcs reduces them to 
 chlorides, with evolution of carbonic anhydride and deposition of sulphur. 5. Heated 
 with aqueous iodic acid in a sealed tube, it yields hydriodic acid, together with iY<-<! 
 iodine and a deposit of sulphur, also sulphuric acid, sulphydric acid, and carbonic an- 
 hydride. Two reactions appear to go on at once, viz. : 
 
 2HI0 8 + CS 2 = I 2 + CO 2 + H 2 SO* + S. 
 
 2HI0 8 + 2CS 2 + 2H 2 = 2C0 2 + 2HI + H 2 S0 4 + H 2 S + S 2 . 
 
 The liquid is at first coloured violet by the free iodine, but on increasing the heat, the 
 colour disappears, in consequence of the action of the sulphydric acid on the iodine, 
 which produces hydriodic acid and free sulphur, the latter imparting a straw-yellow 
 colour to the liquid (Pelouze and Fremy). 6. Sromic acid acts in like manner. 
 7. Many metals decompose disulphide of carbon at a red-heat, taking up the sulphur 
 and setting the carbon free. 8. A mixture of sulphide of carbon vapour and sulphy- 
 dric acid gas passed over red-hot copper yields sulphide of copper and marsh-gas 
 (Berthelot): 
 
 CS 2 + 2H 2 S. + Cu 8 = 4Cu 2 S + CH 4 . 
 
 9. With nascent hydrogen, sulphide of carbon yields sulphydric acid, a crystallised 
 body, CH 2 S, and an oily substance not yet examined (Grirard, Compt. rend, xliii. 39). 
 10. Dry chlorine converts it at a red heat into tetrachloride of carbon ; at ordinary 
 temperatures, into sulphochloride of carbon, CSC1 2 ; but with moist chlorine it yields 
 trichloromethylsulphurous acid (the so-called sulphite of tetrachloride of carbon, 
 CC1 4 S0 2 = S0 3 .CC1 4 (Kolbe). 11. Bromine and sulphide of carbon do not act 
 upon each other when passed through a red-hot tube. 12. Thefixedcatistica/fai/is 
 gradually dissolve disulphide of carbon, forming a brown solution, which is a mixture 
 of carbonate and sulphocarbonate of the alkali-metal (Zeise) : 
 3CS 2 + 3K 2 = K 2 C0 3 + 2K 2 CS 8 . 
 
 13. With alcoholic potash it yields carbonate and ethyl-oxysulphocarbonate (xanthate) 
 of potassium, which forms a yellow precipitate with copper-salts (Zeise) : 
 
 CS 2 + C 2 H 5 .K.O = 
 
 An aqueous or alcoholic solution of caustic potash, boiled with disulphide of carbon, 
 forms with lead-salts a black precipitate of sulphide of lead, which affords a very deli- 
 
CARBON: SULPHOCHLORIDE. 777 
 
 cate test for sulphide of carbon. It is instantly produced on dropping a dilute solution 
 of that compound into a boiling solution of nitrate of lead containing potash, a distinct 
 coloration being obtained, even with a liquid containing only a drop of sulphide of 
 carbon in a quart of water. 14. With aqueous ammonia, it forms sulphocarbonate and 
 sulphocyanate of ammonium, without any carbonate (Zeise) : 
 2CS 8 + 4NH 3 = (NH 4 ) 2 CS 3 + NH 4 .CNS. 
 
 15. With a saturated solution of ammonia-gas in anhydrous alcohol, it yields the same 
 products, together with sulphocarbamate of ammonium, produced by the simple union 
 of ammonia with the disulphide (Zeise): 
 
 CS 2 + 2NH 3 = (NH 2 CS).NH 4 .S. 
 
 16. With tricthylphosphine it unites directly, forming a compound P(C 2 H 5 ) 3 .CS 2 , 
 which crystallises in splendid ruby-coloured prisms. The reaction affords an ex- 
 tremely delicate test for the presence of either of the constituent substances, and is es- 
 pecially applicable to the detection of sulphide of carbon in coal-gas. When a stream of 
 the gas, purified from sulphuretted hydrogen in the usual manner, is passed through a 
 solution of triethylphosphine in ether, contained in a bulb apparatus, a red colour scon 
 appears in the liquid, and when sufficient gas has been passed through the liquid to 
 evaporate the ether, the bulb- apparatus is seen to be lined with a network of the red 
 crystals. (A. W. Hofmann. Ann. Ch. Pharm. cxv. 296.) 
 
 The sulphocarbonates M 2 CS 8 , or M 2 S.CS 2 , bear to disulphide of carbon the same 
 relation that the carbonates M 2 C0 3 bear to carbonic anhydride. Moreover by treating 
 sulphocarbonate of ammonium with dilute sulphuric or hydrochloric acid, an oily, very 
 acid liquid is precipitated, consisting ofsulphocarbouic acid, H 2 CS 3 . 
 
 PHOTO SULPHIDE OF CARBON. CS. As already observed, it is doubtful whether 
 this compound, the analogue of carbonic oxide, has yet been obtained, though there 
 can be no doubt as to the possibility of its existence. Baudrimont (Compt. rend, 
 xliv. 1000), states that it is obtained tolerably pure by passing the vapour of the di- 
 sulphide over red-hot spongy platinum or pumice, and washing the resulting gas with 
 solutions of acetate of lead and cuprous chloride, to free it from sulphydric acid and 
 carbonic oxide, resulting from the action of air and moisture remaining in the 
 materials. The gas thus obtained is described as colourless, smelling somewhat like 
 the disulphide, not liquefiable at the temperature of a mixture of ice and salt ; soluble 
 in its own bulk of water ; decomposed by lime-water into sulphide of calcium, and a 
 volume of carbonic oxide equal to its own : Ca 2 + CS = Ca 2 S -r CO ; and yielding 
 when exploded with oxygen, equal volumes of CO 2 and SO 2 . 
 
 Baudrimont likewise obtained the protosulphide, but mixed with sulphydric acid and 
 carbonic oxide, by passing the vapour of the disulphide over red-hot charcoal ; by the 
 action of sulphydric acid on carbonic oxide at a red heat (CO + H 2 S = H 2 + CS), 
 and by several other processes. 
 
 Playfair (Chem. Soc. Qu. J. xiii. 248) endeavoured to prepare the protosulphide 
 by passing the vapour of the disulphide over red-hot pumice, but obtained nothing but 
 a mixture of carbonic anhydride, carbonic oxide, sulphydric acid, and nitrogen, satu- 
 rated with vapour of disulphide of carbon ; he observed no deposition of sulphur in the 
 red-hot tube, though Baudrimont states that it choked up the exit-tube of his apparatus. 
 Playfair attributes the formation of these gases to air and moisture retained by the 
 pumice, though it had been previously ignited, or introduced into the tube together 
 with the disulphide. He is of opinion that Baudrimont's gas, which yielded by iexplo- 
 sion with oxygen, equal volumes of SO' 2 and CO 2 , was a mixture of equal volumes of 
 CO and vapour of CS 2 , which at common temperatures, and under the diminished 
 pressure existing in the eudiometer, would have sufficient tension to diffuse itself in 
 vapour through the carbonic oxide. 
 
 In face of these contradictory results, the question as to the actual formation of pro- 
 tosulphide of carbon must for the present be considered as undecided. 
 
 CARBOCT, SUX.PKOCHX.ORXDE OP. CSC1 9 . This compound, the analogue 
 of phosgene, was discovered by Kolbe (Ann. Ch. Pharm. xlv. 53), and is produced: 
 1. By the action of dry chlorine on disulphide of carbon at ordinary temperatures, 
 chloride of sulphur being formed at the same time : CS 2 + Cl 4 = SCI 2 + CSCR A few 
 grammes of the disulphide are left exposed for a few days to the action of perfectly dry 
 chlorine in a closed flask, either in the dark or in sunshine ; the resulting liquid is 
 digested with water to decompose the chloride of sulphur, and the remaining oily 
 liquid is freed from the acid products thereby formed, by repeated distillation with 
 water and a small quantity of magnesia. It is essential to the production of this com- 
 pound, that the materials be perfectly dry, as if moisture is present, another compound, 
 trichloro-methyl-sulphurous acid is obtained (p. 776). At a red heat, a different 
 
778 CARBONATES. 
 
 action takes place, and tetrachloride of carbon is produced. 2. By passing a mixture 
 of sulphydric acid and vapour of tetrachloride of carbon through a tube kept at a 
 moderate red heat: 'CC1 4 + H 2 S = 2HC1 H- CSCP. 
 
 Sulphochloride of carbon is a yellow liquid, not miscible with water, having a 
 peculiar and powerful odour, very irritating to the eyes. Specific gravity 1-46. 
 Boiling point 70 C. These numbers probably require correction, as it is very difficult 
 to obtain the compound free from sulphide of carbon. It is not decomposed by water 
 or acids, not even by fuming nitric acid. Caustic potash decomposes it slowly, form- 
 ing carbonate and sulphide of potassium, and tetrachloride of carbon : 
 2CSC1 2 + 3K 2 = K 2 C0 3 + 2K 2 S + CC1 4 . 
 
 CARBONATES. The carbonates form a numerous and important class of salts, 
 many of which occur as natural minerals. They are usually divided into normal, basic; 
 and acid carbonates, the normal or neutral salts having the composition 
 
 M 2 C0 3 = M 2 O.C0 2 = (C Sf JO 2 [or MO.CO*]. 
 
 The basic carbonates, however, all contain water, and by regarding the whole or part 
 of this water (or hydrogen) as basic, the carbonates, like the borates, phosphates, and 
 
 silicates, may be divided into ortho-carbonates, M 4 C0 4 =- -jyj-J O 1 , andmetacar- 
 
 bonates, M 2 C0 3 , or more generally orthocarbonates = M*H 4n - x C D 0' ln , and metacar- 
 bonates = ]M>H 2n - x O0 311 , the latter including the salts usually regarded as neutral 
 carbonates. Nearly all the precipitates obtained by adding a solution of an alkaline 
 carbonate to a salt of a heavy metal, contain water, and may be represented by one or 
 other of these formulae. It is difficult to say whether the ortho- or the meta-carbonates 
 are the more numerous ; but the carbonates of the stronger bases, viz. the alkali-metals 
 and alkaline- earth metals, are certainly meta-carbonates. Only a few acid carbonates 
 are known as definite salts, viz. those of potassium, sodium, and ammonium, and these 
 are metacarbonates containing hydrogen, e.g. mouopotassic metacarbonate, or diacid 
 carbonate of potassium, (KH)CO 3 . 
 
 Carbonates are formed by the action of carbonic acid, or the joint action of water and 
 carbonic anhydride, on metallic oxides or hydrates, not in any case by the union of 
 carbonic anhydride with an oxide without the intervention of water. Lime-water, or 
 milk of lime, absorbs carbonic anhydride rapidly, forming carbonate of calcium ; but 
 perfectly dry carbonic anhydride may be passed over anhydrous lime without ab- 
 sorption. Even dry hydrate of potassium, KHO, absorbs carbonic anhydride but 
 slowly, and soon becomes covered with a crust of acid carbonate of potassium (KHO + 
 CO 2 = KHCO 3 ), which protects the rest from alteration ; but the " moist hydrate, or 
 the aqueous solution, absorbs it with the greatest avidity ; similarly with other bases. 
 The carbonates of the earth-metals proper and heavy metals are most easily obtained 
 by precipitating a soluble salt of the metal with an alkaline carbonate ; but the pre- 
 cipitate, as already observed, almost always contains water, and very rarely has the 
 composition of an anhydrous metacarbonate 1VPC0 3 . The sesquioxides, alumina, 
 feme oxide, chromic oxide, uranic oxide, &c., do not absorb carbonic anhydride even 
 when moist, and their solutions, when mixed with alkaline carbonates, yield precipitates, 
 not of carbonates, but of hydrates. Metals like zinc and iron, which readily replace 
 hydrogen in acid solutions, may be converted into carbonates by simply immersing 
 them in water containing carbonic acid. 
 
 Carbonates are also formed in the decomposition by heat of organic salts of the 
 etronger bases, viz. of the alkali-metals and of the alkaline-earth metals. Oxalates are 
 resolved into carbonates and carbonic oxide, without separation of carbon : 
 
 C 2 M 2 0* = CM 2 3 + CO 
 
 formates into carbonates, with evolution of carbonic oxide and hydrogen, and slight 
 separation of carbon : 
 
 2CHM0 1 = CM 2 3 + CO + H 2 . 
 
 The salts of most other organic acids yield a considerable quantity of free carbon 
 besides combustible gases ; acetates and the salts of other fatty acids, and a few others, 
 are resolved by dry distillation into carbonates and acetones (pp. 31, 32). 
 
 The carbonates of ammonium, potassium, and sodium" are easily soluble in water ; 
 carbonate of lithium dissolves in about 100 pts. of water; the carbonates of all other 
 metals are insoluble, or nearly so, in water; but all are slightly soluble in water 
 containing free carbonic acid. Acid carbonates are doubtless formed in this case ; 
 but none of these, excepting the acid carbonates of the alkali-metals, can be ob- 
 tained in the solid state, as the solutions, when boiled or evaporated, give off car- 
 bonic anhydride and deposit neutral carbonate. All metallic carbonates, excepting 
 
CARBONATES. 779 
 
 carbonate of ammonium, are insoluble in alcohol. Carbonates of organic alkalis are 
 for the most part soluble in water and in alcohol ; carbonates of alcohol-radicles, in- 
 soluble in water, soluble in alcohol. 
 
 Most carbonates are easily decomposed by heat. The carbonates of the heavy metals 
 are all decomposed at a low red heat, giving off carbonic anhydride, and leaving a 
 residue of metal or of oxide. The carbonates of the earth-metals proper, and of calcium 
 and strontium, require a stronger red heat to decompose them ; carbonate of barium is 
 decomposed only at a white heat ; and the carbonates of the alkali-metals, when dry, 
 resist the action of the strongest heat, excepting when a current of dry air or other gas 
 is passed over them ; in that case carbonate of sodium gives up a small quantity of 
 carbonic anhydride, and carbonate of lithium a considerable quantity. (H. Eose.) 
 
 Nearly all carbonates are more or less decomposed by water, with the aid of heat, 
 those of the weaker bases even at ordinary temperatures, so that precipitated car- 
 bonates are very apt to undergo partial decomposition during washing. Even the 
 carbonates of barium, potassium, sodium, and magnesium are converted into hydrates 
 when heated to redness in a stream of aqueous vapour ; partially also in a stream of 
 moist air or hydrogen gas : the carbonates of barium and potassium do not suffer any 
 decomposition in a current of dry air or hydrogen. (H. Kose, Pogg. Ann. Ixxxv. 99, 
 279 ; Jahresber. d. Chem. 1852, p. 309.) 
 
 Carbonates are decomposed, with evolution of carbonic anhydride, by nearly all 
 acids, even at ordinary temperatures, and at a red heat by many acids whose salts are 
 themselves decomposed at ordinary temperatures by carbonic acid, e.g. by boric, silicic, 
 and several metallic acids. The effervescence which accompanies the decomposition 
 affords a ready indication of the presence of a carbonate. Any of the stronger acids may 
 be used to effect the decomposition, but, generally speaking, hydrochloric or nitric acid 
 is preferable to sulphuric acid, because the latter often forms insoluble or sparingly 
 soluble salts, the presence of which interferes with the reaction. If the carbonate is 
 in solution, the liquid should be concentrated before adding the acid, as in a very 
 dilute liquid the carbonic acid may remain dissolved instead of escaping as gas. The 
 decomposing acid must also be added in excess, otherwise an acid carbonate of the 
 alkali-metal will be formed, and no effervescence will be observed. If the substance 
 to be examined is a mineral, it must be finely pulverised, and the powder should bo 
 soaked in water before adding the acid ; otherwise the escape of air-bubbles might be 
 mistaken for an evolution of carbonic anhydride. Many other volatile acids produce 
 effervescence when eliminated from these compounds, e.g. hydrochloric, hydriodic, 
 sulphurous, sulphydric acid, &c. ; but they may all be distinguished from carbonic 
 acid by their colour or their odour, also by passing the evolved gas into lime-water 01 
 baryta- water, and proceeding as described at page 768. 
 
 CARBONATE OF ALUMINIUM (?) It is doubtful whether such a compound exists. 
 Saussure stated long ago that alkaline carbonates throw down from solutions of alu- 
 minium, a compound of hydrate of aluminium with a small quantity of the alkaline 
 carbonate, and that the hydrate is partially soluble in aqueous carbonic acid, but is 
 completely separated on warming the solution or exposing it to the air (Grm. iii. 309). 
 Other chemists have, however, obtained different results. According to Muspratt 
 (Chem. Soc. Qu. J. ii. 206), the precipitate formed by alkaline carbonates consists oi 
 3A1 4 3 .2C0 2 + 16H 2 0. Langlois (Ann. Ch. Phys. [3] xlviii. 502) found SAl'O 3 . 
 3C0 3 + 40H 2 0; and Wallace (Chem. Gaz. 1858, 410) gives, as the composition oi 
 the precipitate, 3A1 4 3 .2C0 2 + 9H 2 0. H. Eose, on the contrary (Pogg. Ann. xli. 
 462), states that the precipitate formed by carbonate of ammonium is a compound of 
 trihydrate of aluminium with carbonate of ammonium, A1 2 H 3 3 + NH 4 .H.C0 3 , the 
 ammonia-salt not being removable by washing. From experiments recently made in 
 Dr. Muspratt's laboratory by Mr. James Barratt (Chem. News, i. 110), it appears 
 that the precipitate formed by carbonate of sodium in a solution of chloride of alu- 
 minium, after being washed and dried, then triturated with water, again washed, and 
 dried over sulphuric acid, consists of pure hydrate of aluminium. 
 
 CARBONATE OF ALLYL. See CARBONIC ETHERS. 
 
 CARBONATES OF AMMONIUM. These salts have already been described (p. 190), 
 They are all metacarbonates, and may be formulated as follows : 
 
 Neutral carbonate, (NH 4 ) 2 O.C0 2 = 
 
 Acid carbonate, 4 JO.C0 2 = 
 
 Seequicarbonate, 2(NH<) 2 0.3C0 2 + 3aq. = /- + aq. 
 
780 CARBONATES. 
 
 CARBONATE OF AMYL. See CARBONIC ETHERS. 
 
 CARBONATE OF BARIUM. Ba 2 C0 8 = Ba 2 O.C0 2 . This salt occurs abundantly 
 in nature as Withcrite, a mineral which frequently accompanies lead-ores. It crys- 
 tallises in the trimetric system, isomorphously with arragonite, the crystals being 
 frequently prismatic, from predominance of the faces oo P, oo P oo, and t oo. The com- 
 bination P . 2 oo . oo GO . OD P, is also common, forming a six-sided prism with 
 pyramidal summits. Ratio of axes, a : b : c = 0'5950 : 1 : 0'7413. Inclination of 
 faces: oo P : oo P =61 30' ; P oo : P oo = 71 47' ; 2P oo : 2P oo = 110 42'. Cleavage 
 imperfect parallel to oo P oo, oo P, and P oo (Kopp). It occurs also in globular, tuberose, 
 and botryoi'dal forms ; structure either columnar or granular ; also amorphous. Specific 
 gravity = 4*29 to 4*35. Hardness = 3 to 375. Lustre vitreous, inclining to resinous 
 on fractured surfaces. Colour white, or often yellowish or greyish. Streak white. 
 Subtransparent to translucent. Fracture uneven. Brittle. Witherite is found on 
 Alston Moor in Cumberland, and in splendid crystals at Fallowfield in Northumber- 
 land. It occurs also in many places on the continent of Europe, in the Altai, near 
 Coquimbo, Chili, &c. It is sometimes found altered to heavy spar by the action of 
 soluble sulphates. 
 
 Carbonate of barium is rapidly formed when baryta, either in the anhydrous state, 
 or in crystals, or in solution, is exposed to the air, and is easily prepared by precipi- 
 tating an aqueous solution of the chloride or nitrate with carbonate of ammonium, or 
 a solution of the sulphide with carbonate of sodium ; the salt, obtained by this last 
 method is liable to be contaminated with a sulphur-compound. It may also be pre- 
 pared in an impure state by igniting in a crucible a mixture of 10 pts. of native 
 sulphate of barium, 2 pts. of charcoal, and 5 pts. of carbonate of potassium (pearl-ash). 
 A mixture of sulphide of potassium and carbonate of barium is then obtained, from 
 which the sulphide of potassium may be extracted by water. The impure carbonate 
 thus produced may be used for the preparation of other barium-salts, but the salts thus 
 obtained will contain iron. 
 
 Carbonate of barium artificially prepared is a soft white powder. It is poisonous, 
 and is used as rat-bane. It is vt'jy slightly soluble in water, about 1 pt. in 4000, 
 rather more (in 588 pts. according to Lassaigne) in water saturated with carbonic acid. 
 It dissolves easily, even in the cold, in chloride, nitrate, and succinate of ammonium, 
 and when boiled with chloride of ammonium, it is completely decomposed, yielding 
 carbonate of ammonium and chloride of barium. When shaken up with aqueous sul- 
 phate of potassium or sodium, it yields sulphate of barium and carbonate of the alkali- 
 metal. It bears a strong red heat without decomposition ; but at the heat of a forge- 
 fire it gives off carbonic anhydride and leaves baryta. The decomposition is greatly 
 facilitated by the addition of charcoal. Carbonate of barium is decomposed by vapour 
 of water at a red heat, and very easily if mixed with an equal weight of chalk or 
 slaked lime. 
 
 An acid carbonate, 2Ba 2 0.3C0 2 , or 2Ba 2 C0 3 .C0 2 , was said by Boussingault (Ann. 
 Ch. Phys. [2] xxix. 280) to be obtained by precipitating chloride of barium with ses- 
 quicarbonate of sodium. H. Rose, on the other hand, by mixing chloride of barium 
 with diacid carbonate of sodium or potassium, obtained nothing but neutral carbonate 
 of barium, and is of opinion that acid carbonates of barium cannot exist excepting in 
 solution. 
 
 CARBONATE OF BISMUTH. When nitrate of bismuth is dropt into a solution of 
 alkaline carbonate, a white precipitate is formed, consisting of Bi 2 3 .C0 2 (Berzelius). 
 The precipitate formed with alkaline carbonates contains Bi 2 3 .C0 2 + aq., the water 
 escaping at 100 C. (Lef ort.) 
 
 CARBONATE OF CADMIUM, Cd 2 CO s , occurs in small quantity, associated with 
 native carbonate of zinc. Cadmium-salts yield with carbonate of ammonium, a white 
 precipitate, containing Cd 2 C0 3 + aq., which gives off its water between 80 and 120 C. ; 
 at a higher temperature, carbonic anhydride goes off, and brown oxide of cadmium is 
 left, which when exposed to the air is gradually reconverted into carbonate (Lef ort, 
 J. Pharm. [3] xii. 406). According to H. Rose (Pogg. Ann. Ixxxv. 304), the preci- 
 pitates formed by alkaline carbonates in solutions of cadmium, contain very little water, 
 and approach very nearly to the formula Cd 2 C0 3 . Moist hydrate of cadmium absorbs 
 carbonic acid from the air, and at 300 gives off all its water, and is converted into 
 2Cd 2 O.Cd 2 C0 3 , or Cd 2 O.Cd<CO*. 
 
 CARBONATES OF CALCIUM. The metacarbonate, Ca 2 CO s = Ca 2 O.C0 2 , occurs most 
 abundantly in all parts of the world, in the forms of calcspar, marble, limestone of various 
 kinds, and chalk ; also in egg-shells and the shells of molluscs, and, together with phos- 
 phate of calcium, in bones. It is formed when lime, either anhydrous or hydrated, is 
 exposed to the air in its ordinary state of moisture, but not by the action of carbonic 
 anhydride on anhydrous lime. It may be obtained pure by dissolving calcined oyster 
 
CARBONATES. 781 
 
 shells, chalk, or marble, in hydrochloric acid, adding ammonia or milk of lime to pre 
 cipitate alumina, oxide of iron, and earthy phosphates, then filtering, precipitating tht 
 hot filtrate with carbonate of ammonium, washing thoroughly, and drying at a heat 
 short of redness. 
 
 Carbonate of calcium is dimorphous, crystallising in the hexagonal system as calcspar 
 (p. 721), and in the trimetric system as arragonite (p. 358). The specific gravity of 
 the former varies from 2-6987 to 275 ; of the latter, generally from 2'92 to 3*28. The 
 artificially prepared salt is a white powder, consisting of small crystals, which usually 
 take the form of arragonite when precipitated from hot solutions, and of calcspar when 
 precipitated from cold solutions, especially if dilute. The microscopic crystals of arra- 
 gonite gradually change into rhombohedrons of calcspar if left for some time under the 
 cold liquid (p. 359). The precipitate formed in hot solutions, assumes the crystalline 
 character at once ; that from cold solutions is amorphous at first, and gradually becomes 
 crystalline. 
 
 Carbonate of calcium is tasteless, and has a slight alkaline reaction to test-paper. 
 It is very sparingly soluble in water, requiring, according to Fresenius (Ann. Ch. 
 Pharm. lix. 117), 88-34 pts. of boiling, and 10,601 pts. of cold water to dissolve it; the 
 solution is slightly alkaline. Water containing free carbonic acid dissolves it much 
 more freely. When recently precipitated, it dissolves easily in aqueous carbonate, sul- 
 phate, hydrochlorate, nitrate, or succinate of ammonium : but when it has assumed the 
 crystalline form by long standing, it dissolves but sparingly, forming a turbid liquid. 
 The clear solutions sometimes become turbid on standing, but do not deposit the whole 
 of the calcium which they contain. Hence calcium can never be completely precipi- 
 tated as carbonate from solutions containing ammoniacal salts. Carbonate of calcium 
 boiled with solution of sal-ammoniac, the water being renewed as it evaporates, dis- 
 solves almost completely as chloride of calcium, with evolution of carbonate of am- 
 monium. 
 
 Carbonate of calcium heated to full redness in open vessels, is resolved into lime and 
 carbonic anhydride. The decomposition commences even at a low red heat, so that in 
 estimating calcium as carbonate in analysis, the ignited precipitate should, before 
 weighing, be moistened with carbonate of ammonium, and again heated, just sufficiently 
 to drive off the excess of that salt ; by this means, any carbonic acid that may have 
 been driven off will be restored. In a current of air or any other gas, and especially of 
 steam, the decomposition takes place at a lower temperature. If, on the other hand, 
 the carbonate of calcium be ignited a closed iron tube, so that the carbonic anhydride 
 cannot escape, it fuses to a fine-grained mass, consisting of crystals of calcspar, and 
 having the appearance of marble. 
 
 Hydrated Neutral Carbonate of Calcium, Hydrocalcite, Ca 2 C0 3 .5aq. This salt is 
 obtained in small, very acute, rhombohedral crystals, of specific gravity 1'783, by boil- 
 ing lime in a concentrated solution of sugar, milk-sugar, starch, or gum, and leaving 
 the solution for some months in a cold place (Pelouze, Ann. Ch. Phys. [2] xlviii. 301). 
 Becquerel, by exposing a solution of lime in sugar-water, to the action of a 12-pair 
 voltaic battery, obtained crystals having the same composition, but the form of a 
 rhombic prism with dihedral summits, like arragonite. Crystals of the same form and 
 composition were found by Scheerer (Pogg. Ann. Iviii. 382), in a running stream. 
 Sal m-Horstmar found six-sided prisms of the same composition, deposited from spring- 
 water in the copper tube of a pump. 
 
 The crystals remain unaltered below 19 or 20 C., either in the air or under 
 water, but crumble to a white powder at a somewhat higher temperature, and if quickly 
 heated to 30, they are converted into a pasty mass, which dries up to a powder. In 
 ether at 30, they crumble to a white powder ; also in hydrated alcohol : but boiling 
 absolute alcohol extracts from them only 2 at. water, rendering them opaque, but with- 
 out change of form. The remaining crystals with 3 at. water, effloresce very quickly 
 in the air, but may be kept unaltered at a temperature below 10. (Grm. iii. 188.) 
 
 Orthocarbonate, Ca 4 C0 4 , or 2Ca 2 O.C0 2 . This, with 1 at. water (sometimes regarded 
 as a hydrocarbonate, Ca 2 COV2CaIIO), is, according to Fuchs (Pogg. Ann. xxvii. 601), 
 the composition of the slaked lime produced by exposing quick lime to the air in its 
 ordinary state. At a strong red heat, it gives off water and carbonic anhydride, and 
 yields a quick lime which slakes in water, not with violence, but slowly and with only 
 moderate rise of temperature. At a low red heat, the hydrated Orthocarbonate gives off 
 only water, leaving the anhydrous salt, Ca 4 C0 4 , which, according to Fuchs, is likewise 
 produced when ordinary carbonate of calcium is exposed to a moderate red heat, only 
 half of the carbonic anhydride being then expelled, and leaving a residue, which in 
 contact with water does not slake but hardens, being in fact converted into the hydrated 
 Orthocarbonate. 
 
 Acid Carbonate. This salt, which perhaps has the composition CaHCO 3 , is known 
 only in solution, and may be obtained in that state by passing carbonic anhydride into 
 
782 CARBONATES. 
 
 cold water in which the neutral carbonate is suspended. Water saturated with car- 
 bonic acid dissolves j-^ part of the neutral carbonate, at C., and TT L_ a t 10 
 (Lassaigne, J. Chim. med. 1848, p. 312). In consequence of this sparing solubility, 
 solutions of calcium-salts are precipitated by alkaline bicarbonates even in the cold. 
 The solution of the acid salt has a slight alkaline reaction if quite saturated, but if the 
 carbonic acid is in excess, it exhibits an acid reaction. It is decomposed, with sepa- 
 ration of the neutral carbonate, on exposure to the air, or more quickly when heated. 
 It plays an important part in the economy of nature, being formed wherever carbonate 
 of calcium or other calcareous formations, especially silicates, come in contact with 
 water containing carbonic acid, and thus entering in greater or smaller quantity into 
 the composition of almost all natural waters. Waters which contain it in considerable 
 quantity, form deposits of carbonate of calcium on their banks or on objects immersed 
 in them: hence the formation of calcareous petrifactions, of calcareous tufa and 
 sinter, of stalactites, stalagmites, &c. To the same cause also is due the turbidity 
 which appears in river or spring water when heated, and the incrustation or furring of 
 kettles and boilers. The formation of this incrustation may to a certain extent be 
 prevented, by the addition of sal-ammoniac to the water, whereby, as already observed, 
 the carbonate of calcium is converted into soluble chloride. 
 
 CARBONATE OF CERIUM, Ca 2 C0 3 + 3aq., or Ce 2 H 2 C0 4 + 2aq., formed, on ex- 
 posing hydrated cerous oxide to the air, or by precipitation, is a white powder, which 
 when ignited the air, is partly converted into lemon yellow coroso-ceric oxide. It 
 occurs native, with fluoride of calcium, as Parisite (q. v.) 
 
 CHROMOUS CARBONATE, is obtained by adding a solution of protochloride of 
 chromium to carbonate of potassium. The precipitate is red or reddish-brown, if the 
 solution is hot, but has the form of dense yellow or bluish-green flakes, if the solution is 
 cold : it appears, however, to have the same composition in all cases. (Mo berg.) 
 
 CARBONATES OF COBALT. The anhydrous carbonate Co 2 C0 3 , is obtained by 
 heating chloride of cobalt with carbonate of calcium to 150 C. in a sealed tube for 
 eighteen hours, or by decomposing the chloride with a solution of acid carbonate of 
 sodium supersaturated with carbonic acid, and heated to 140 in a strong vessel closed 
 with a cork, through which the carbonic acid escapes slowly. It is a light rose- 
 coloured, sandy powder, composed of microscopic rhombohedrons, and is not attacked in 
 the cold by acids, not even by nitric or hydrochloric acid. (Senarmont, Ann. Ch. 
 Phys. [3] xxx. 129.) 
 
 The precipitates formed by adding cobalt-solutions to alkaline carbonates, are all 
 hydrated carbonates, or double carbonates of cobalt and the alkali -metal. The former 
 may be represented as ortho- or meta-carbonates, combined in various proportions with 
 hydrate of cobalt, the composition varying according to the temperature and concen- 
 tration of the solutions. 
 
 The precipitate formed on adding sulphate of cobalt to neutral carbonate of sodium, 
 the solutions being concentrated or moderately dilute, and either hot or cold, is rose- 
 coloured, and when dried at 100 C., consists of Co 2 C0 3 .3CoHO + |aq., or Co 4 C0 4 .CoHO 
 f |aq. (Setterberg, Fogg. Ann. xix. 55; Winkelblech, Ann. Ch. Pharm. xiii. 
 148 ; H. Rose, ibid. Ixxx. 237). But very weak solutions mixed at the boiling h< at, 
 yield a blue precipitate, consisting of Co 2 C0 3 .4CoHO + aq., or Co 4 C0 4 .2CoIIO + 2aq. 
 The precipitates are very difficult to wash. Heated above 150 C. in contact with the 
 air, they gradually give off water and carbonic anhydride, and are converted into 
 sesquioxitle of cobalt (H. Rose). The first-mentioned precipitate is partly converted 
 into sesquioxide by boiling with water (Field, Chem. Soc. Qu. J. xiv. 50). The 
 name precipitate digested with solution of diacid carbonate of sodium or of ammonium, 
 is gradually converted into 3Co 2 C0 3 + aq. (H. Deville, Ann. Ch. Phys. [3] 
 xxxiii. 75.) 
 
 A hydrated carbonate of cobalt called Remingtonite, whose precise composition is 
 not known, occurs as a soft, earthy, rose-coloured incrustation, on thin veins of serpen- 
 tine, at a copper-mine near Finksburg. Carroll County, Maryland. (J. C. Booth, Sill. 
 Am. J. [2] xv. 48.) 
 
 Carbonate of Cobalt and Potassium. Nitrate or sulphate of cobalt forms with excess 
 of diacid carbonate of potassium a rose-coloured precipitate, which gradually changes 
 to a network of rose-coloured crystals, easily decomposed by water, and consisting of a 
 meta-carbonate, (Co 2 KH)C 2 O 6 + 4aq., [or 2(CoO.C0 2 ) + K0.2C0 2 + 9HO](II. Rose, 
 H. Deville). Nitrate of cobalt and sesquicarbonate of potassium, yield distinct crys- 
 tals, containing CoKCO 3 + 2aq. (Deville.) 
 
 Carbonate of Cobalt and Sodium. Nitrate of cobalt and sesquicarbonate of sodium, 
 yield a mixture of small prismatic crystals, CoNaCO 3 + 2 aq., and dark-red crystals, 
 apparently cube-like rhombohedrons, containing CoNaC0 3 + 5aq. (Deville). 
 
CARBONATES. 783 
 
 CARBONATES OF COPPER. Two of these compounds occur as natural minerals, 
 riz. Malachite and Azurite. They may be most simply represented as orthocarbonates, 
 viz. : 
 
 Malachite as tctracupric Orthocarbonate, Cu 4 C0 4 + aq. 
 
 Cu 3 ) 
 Azurite as tricupric Orthocarbonate, TT [CO*. 
 
 They may also be regarded as metacarbonates combined with cupric hydrate, viz. 
 malachite as Cu 2 C0 3 .2CuHO ; azurite as Cu 2 CO 3 .CuHO. The hydrated tetracupric 
 salt is formed artificially by precipitation. The anhydrous metacarbonate Cu 2 C0 3 , is 
 not known. 
 
 Tetracupric Orthocarbonate, Cu 4 C0 4 + aq. Malachite, Green Carbonate of 
 Copper, Mountain green, Atlas ore. This mineral forms prismatic crystals belonging to 
 the monoclinic system, in which the lengths of the orthodiagonal, clinodiagonal, and prin- 
 cipal axis are to one another as 1/273 : 1 : 0-5358. The inclination of the clinodiagonal 
 to the principal axis does not differ.inuch from 90. The crystals are generally reduced 
 to thin prisms by predominance of the faces ooP and ooP oo, and terminated by oP, + P, 
 P oo. Cleavage perfect parallel to P oo and ooP (Kopp). More frequently, how- 
 ever, it occurs in laminar, fibrous, compact, or earthy masses. Specific gravity = 3*7 
 to 4*0. Hardness = 3 '5 to 4. It varies in colour from emerald to grass-green, and 
 exhibits all degrees of transparency down to perfect opacity. It takes a high polish, 
 and when in large masses is cut into tables, snuff-boxes, vases, &c. Malachite usually 
 accompanies other ores of copper. Perfect crystals are very rare. The fibrous variety 
 occurs abundantly in Siberia, at Chessy in France, at Sandlodge in Shetland ; the com- 
 pact variety at Schwartz in the Tyrol, in Cornwall, and in Cumberland. At the copper 
 mines of Nisclme Tagilsk, a bed of malachite was opened which yielded many tons of 
 the mineral. Malachite is also found on the west coast of Africa, and in several 
 localities in North America. (Dana, ii. 458.) 
 
 Cupric salts treated with alkaline carbonates, yield at first a greenish-blue preci- 
 pitate, consisting, according to Brunner, of Cu 4 CO' + 2aq. ; which, however, when left 
 in contact with the liquid, and washed, becomes compact and green, and acquires the 
 composition of malachite. When heated to 200 C. it is slowly converted into black 
 cupric oxide, which obstinately retains a small quantity of water. Malachite slowly 
 decomposes in the same manner at 220. The tetracupric salt, either native or preci- 
 pitated, is decomposed by boiling with water, giving up carbonic acid, and being entirely 
 converted into black oxide of copper. (H. Kose ; F. Fi eld, Chem. Soc. Qu. J. xiv. 71.) 
 By digestion with neutral carbonate of sodium at 120 F. (48*8 C.) it is converted 
 into GCu'O.CO 2 , or Cu 4 C0 4 .4Cu 2 0. Boiled with sesquicarbonate of sodium, it dissolves, 
 forming a blue liquid, which is not decomposed even by long boiling ; but when sulphate 
 of copper is boiled for a very long time with sesquicarbonate of sodium, a green precipi- 
 tate of tetracupric carbonate is obtained, and on filtering from this and adding more sul- 
 phate of copper to the filtrate, the basic salt just mentioned is precipitated, as a dense 
 black powder (Field). According to Deville, tetracupric carbonate digested with 
 neutral carbonate of sodium, is partly converted into 8Cu 2 O.C0 2 + 5H 2 0. 
 
 Anhydrous tetracupric carbonate, Cu 4 C0 4 , or 2Cu 2 O.C0 2 , occurs, according to 
 Thomson (Mineralogy, i. 601), as mysorin, a mineral from Mysore in Hindostan, con- 
 taining also ferric oxide and silica. Dana suggests that it may be only an impure 
 malachite. 
 
 Tricupric Orthocarbonate, Cu 3 HC0 4 (or BCu0.2CO* + aq.) Azurite, Lasurite, 
 Blue Carbonate of Copper, Blue Malachite, Chessy Copper, Chessylite, Kupferlasur. This 
 mineral occurs in fine crystals, belonging to the monoclinic system, in which the orthodiago- 
 nal, clinodiagonal, and principal axis are to one another as 1*181 : 1 : 2'076. Inclination 
 of axes 87 39'. Observed faces ooP . oP. [Poo ] . [iPoo ]. ooPoo , together with others of 
 less frequent occurrence. The crystals are often prismatically elongated in the direc- 
 tion of the orthodiagonal. Cleavage parallel to [Poo ] (Kopp's Krystallographie, 
 p. 303). The mineral occurs also massive and in imitative shapes, having a columnar 
 composition, also dull and earthy. Specific gravity =3*5 to 3*831. Hardness = 3*5 
 to 4*25. Lustre vitreous, almost adamantine. Colour, various shades of azure, passing 
 into Prussian-blue. Streak-blue, lighter than the colour. Transparent to sub-translucent. 
 Fracture conchoidal. Brittle. It is found in splendid crystallisations at Chessy near 
 Lyons, in fine crystals also in Siberia, at Moldavia in the Bannat, at Wheal Buller, 
 near Redruth in Cornwall ; at Porto Bello, South America ; and in small quantities 
 at Alston Moor, Wanlockhead, &c. It is found also in the States of Pennsylvania, 
 New York, and New Jersey. (Dana, ii. 459.) 
 
 Azurite when ground to fine powder forms a bright blue pigment ; but it is not of 
 muctt use, as it is apt to turn green by exposure. When boiled with water, it decom- 
 
784 CARBONATES. 
 
 poses like malachite, yielding black oxide of copper. Heated with a concentrated so- 
 lution of diacid carbonate of sodium, it yields a blue solution, which, after protracted 
 boiling, deposits a green precipitate of malachite (Field). According to Phillips 
 (Ann. Ch. Phys. [2] vii. 44) a cupric carbonate, called blue verditer, having the same 
 composition as azurite, is obtained by a secret process. 
 
 Potassio-cupric Carbonate. Nitrate of copper forms with diacid carbonate of potas- 
 sium, a deep blue liquid, which after a few hours deposits a silky mass, consisting of 
 5Cu*O.K 2 0.5C0 2 + 10 aq. or (Cu oK'H^O 20 + 6 aq. (Deville, Ann. Ch. Phys. [3] 
 xxxiii. 75). 
 
 Sodio-cupric Carbonate, CuN"aC 2 3 + 3 aq., is obtained by adding an acid solution of 
 nitrate of copper to carbonate of potassium containing soda, and leaving the precipitate 
 in the liquid for a considerable time ; also by the action of diacid carbonate of sodium 
 on tetracupric carbonate at 40 50 C. It forms rhombic prisms, having the angles of 
 the obtuse edges = 123 14', and acuminated with four faces resting on the prismatic 
 edges. (Deville.) 
 
 Cuprous Carbonate ? The yellow precipitate obtained by adding carbonate of sodium 
 to a solution of cuprous chloride in hydrochloric acid was said by Colin to be a cuprous 
 carbonate, but according to L. G-melin (Handbook, v. 414), it is merely cuprous 
 hydrate. 
 
 Carbonate of Cuprammonium, (NH 3 Cu) 2 C0 3 , is obtained in large deep blue crystals 
 by dissolving tricupric or tetracupric carbonate in carbonate of ammonia, and pouring 
 the solution into alcohol. It is rapidly decomposed by water into carbonate of am- 
 monia and a basic carbonate of copper, Cu 4 C0 4 .2CuHO + 2 aq. (Favre, Traite de 
 Chimie par Pelouze et Fremy, iii. 201). The same ammoniacal compound appears to 
 be formed when cupric oxide or finely divided metallic copper is digested in ammonia 
 with access of air. 
 
 CARBONATE OF DIDYMIUMIS obtained as a white, slightly rose-coloured precipi- 
 tate containing Di 2 C0 3 + 2 aq., on adding an alkaline carbonate to the solution of a 
 didymium-salt. At 100 C. it gives off two-thirds of its water and a small quantity of 
 carbonic acid. (Marignac.) 
 
 CARBONATE OF ETHYL. See CARBONIC ETHERS. 
 
 CARBONATE OF GLUCINTJM is produced when the hydrate is exposed to the air, 
 also by precipitating glucinum-salts with alkaline carbonates, not in excess, and by 
 boiling a solution of carbonate of glucinum and ammonium. It appears to vary in com- 
 position ; the precipitate obtained by the last-mentioned process has, according to 
 Schaffgotsch, the composition 5GFO.C0 8 + 5aq. or G1 4 C0 4 .6G1HO + 2aq. It appears 
 to be decomposed by boiling with water. It dissolves in alkaline carbonates, forming 
 double salts. 
 
 Carbonate of Glucinum and Ammonium. When a solution of glucina in aqueous car- 
 bonate of ammonia is heated to the boiling point, till the liquid begins to show turbidity, 
 then filtered, and the filtrate mixed with alcohol till it becomes milky, white tran- 
 sparent crystals are gradually deposited, containing 4G1 2 0.3C0 2 .H 2 \- 3[(NH 4 ) 2 O.C0 3 ] 
 or perhaps G1H0.3G1(NH 4 )C0 3 . They become dull on exposure to the air, are inso- 
 luble in absolute alcohol, but dissolve readily in cold water, and are decomposed by 
 hot water, with evolution of carbonate of ammonia. (Deb ray, Ann. Ch. Phys. [3] 
 xliv. 5.) 
 
 Carbonate of Glucinum and Potassium, G1H0.3G1KC0 9 , is obtained in the same 
 manner as the ammonium-salt, which it resembles in its properties. (Debray.) 
 Carbonate of glucinum likewise forms a double salt with carbonate of sodium. 
 CARBONATES OF IRON. Ferric carbonate does not appear to exist. The precipitate 
 formed by alkaline carbonates in solution of ferric nitrate, consists, according to 
 L. Gmelin (Handbook, v. 222), of ferric hydrate without a trace of carbonic acid. 
 According to Soubeiran (Ann. Ch. Phys. [2] xliv. 326), the precipitate thrown down 
 by alkaline carbonates from ferrous salts, contains, after thorough washing and expo- 
 sure in thin layers to the moist air of a cellar for six months, 71*4 per cent, ferric 
 oxide (quite free from ferrous oxide), 8'3 carbonic anhydride, and 20 water ; but it 
 is doubtful whether a definite carbonate is formed. 
 
 Double carbonates of ferricum and the alkali-metals appear to be capable of existing 
 in solution, though not in the solid state. When a ferric salt is precipitated by con- 
 centrated carbonate of ammonia, the precipitated ferric hydrate gradually redisssolves, 
 but is slowly deposited again on diluting with water. Well washed ferric hydrate, 
 however, does not dissolve in carbonate of ammonia, so that the presence of the ammo- 
 niacal salt formed in the decomposition appears to be necessary to the solution of the 
 ferric hydrate. Similar reactions are obtained with strong solutions of carbonate of 
 potassium or sodium. 
 
 Ferrous Carbonate. The anhydrous metacarbonate Fe 2 C0 3 or Fe'O.CO 2 , exists 
 abundantly as a natural mineral, viz. Spathic or Sparry iron ore, also called Cho.ii)- 
 
CARBONATES. 785 
 
 bite, Sideritc, Siderosc, Brown spar, Sphcerosiderite, Junkerite, Strahlstcin, Eisenspath, 
 Spathdscnstdn, Oligonspath. This mineral forms rhombohedral crystals, having for 
 their primary form a rhombohedron, in which the principal axis is to the secondary 
 axes as 0-8117: 1, and the inclination of the faces meeting in the terminal edges 
 = 107 0', this form being either solitary or predominant, and often with curved 
 faces; sometimes in twin-crystals. It also occurs in botryo'idal and globular forms (as 
 sph&rosiderite), occasionally in silky fibrous masses; often cleavable massive, with^ cleav- 
 age planes undulate ; also coarse or fine granular. Specific gravity = 37 to 3'9. 'Hard- 
 ness = 3 '5 to 4-5. Lustre vitreous to pearly. Streak white. Colour ash-grey, yellowish- 
 grey, greenish-grey ; also brown and brownish-red, rarely green ; sometimes white. 
 Translucent to subtranslucent. Fracture uneven. Brittle. (Dana, ii. 445.) 
 
 Pure ferrous carbonate would contain 37'93 per cent, carbonic anhydride and 62'07 
 ferrous oxide. The mineral always contains more or less of the carbonates of manga- 
 nese, magnesium, and calcium. A black variety from Babbowsky gave 36-61 CO 2 , 
 57-91 Fe 2 0, 1*51 Mn 2 0, trace of Mg 2 0, 0*59 Ca 2 0, and 0-60 gangue. A specimen 
 from the neighbourhood of Durham yielded 35'90 CO 2 , 54'57 Fe 2 0, 1-15 Mn'O, 3'18 
 Ca 2 0, and 2-63 water ( = 97'43). The variety called oligonspar contains 25-31 per 
 cent, manganous oxide ; other varieties contain 12 to 15 per cent, magnesia. 
 
 Ferrous carbonate is a very abundant mineral, occurring in gneiss, mica slate, clay 
 slate, and in connection with the coal formation. At Freiberg it occurs in silver mines. 
 In Cornwall it accompanies tin. It is also found accompanying copper and iron py- 
 rites, galena, vitreous copper, &c. In New York, according to Beck, it is almost 
 always associated with specular iron. Occasionally it is found in trap rocks as sphse- 
 rosiderite (Dana). A siliceous or argillaceous variety called clay iron stone, which 
 occurs in the coal measures, is one of the most abundant and valuable ores of iron. 
 Very large quantities of it are found and worked in South Staffordshire, at Merthyr 
 Tydvil in South Wales, and near Glasgow. 
 
 Anhydrous ferrous carbonate may be prepared artificially by processes similar to those 
 already described for carbonate of cobalt (p. 782). It then forms a greyish-white crys- 
 talline sand, composed of minute rhombohedrons, scarcely attacked by dilute acids, 
 nearly unalterable in dry air, gradually assuming a light red tint in moist air. It is 
 of a darker grey colour and less alterable in the air in proportion as the heat em- 
 ployed in its preparation has been greater and longer continued. (Senarmont, Ann. 
 Ch. Phys. [3] xxx. 129.) 
 
 Hydratcd ferrous carbonate is precipitated on mixing a ferrous salt with an alkaline 
 carbonate, in thick white flakes, which, on exposure to the air, absorb oxygen and give 
 off carbonic acid, first assuming a dirty green colour, and ultimately changing to yel- 
 lowish-brown ferric hydrate. Hence it is difficult to obtain the precipitated ferrous 
 carbonate in a pure and definite state. The best mode of proceeding is to precipitate 
 ferrous sulphate quite free from ferric sulphate, with alkaline monocarbonate or 
 bicarbonate, both salts being dissolved in water which has been thoroughly freed 
 from air by boiling, wash the precipitate out of contact with the air, e. g. by decan- 
 tation with thoroughly de-aerated water, keeping the vessel quite full and closed, and 
 dry it in an atmosphere of carbonic anhydride. The salt thus prepared is a greenish 
 tasteless powder, which is used in medicine; it is tolerably permanent if thoroughly dried; 
 but if moist it oxidises quickly in the air, becoming hot, and giving off water and car- 
 bonic acid. It may be rendered more permanent by mixing it with sugar while 
 moist. 
 
 Acid Salt. Aqueous carbonic acid dissolves ferrous carbonate ; also metallic iron 
 with evolution of hydrogen. The solution, which exists in many natural waters, called 
 chalybeate waters, is colourless, has a slightly ferruginous taste, is decomposed, with 
 separation of ferric hydrate, by contact with the air, and gives a black precipitate with 
 sulphuretted hydrogen. To preserve chalybeate water in vessels, they must first be 
 filled with 'carbonic anhydride, then opened and filled below the surface of the water, 
 and lastly corked under water. A less efficient mode of preservation is the introduc- 
 tion of iron wire and a few grains of sugar. 
 
 CARBONATE OF LANTHANUM, La 2 C0 3 + 3aq., is found native as Lanthanite, a 
 mineral (formerly mistaken for carbonate of cerium) occurring in four-sided plates or 
 minute tables of the trimetric system, with bevelled edges ; also fine-granular, and 
 earthy. Specific gravity 2 -6 7 (?) Hardness 2'5 to 3. It has a dull or pearly lustre, 
 and greyish-white, faint pink, or yellowish colour. It is found coating cerite at 
 Bastnas in Sweden, and in silurian limestone, with the zinc ores of the Saucon valley, 
 Lehigh county, Pennsylvania. The American mineral was found by J. L. Smith to 
 contain 54'90 per cent. La 2 0, with oxide of didymium, 22*58 CO 2 , and 24*09 water 
 ( = 101-57), the formula requiring 52-94 La 2 0, 21-11 CO 2 , and 25'95 water. With borax 
 or phosphorus-salt it yields a glass having an amethystine colour, arising from didy- 
 inium. (Dana, ii. 456.) 
 
 VOL. I. 3 E 
 
786 CARBONATES. 
 
 Carbonate of lanthanum obtained by precipitation forms a white gelatinous mass, 
 which gradually changes into shining crystalline scales. 
 
 CARBONATES OF LEAD. The anhydrous metacarbonato, Pb"C0 3 orPb 2 O.CO 2 , is 
 found native as white lead ore or ccrusite, in crystals of the trimetric system, isomor- 
 phous with arragonite, witherite, and strontianite, and in which the brachydiagonal, 
 macrodiagoual, and jprincipal axis are in the ratio of O'Gl 00 : 1 : 07236. Ordinary com- 
 bination P. coP.Pco.2PooooPoo, with 2$ oo predominant. Inclination of faces, 
 oo P: oo P = 62 46'; Poo : Poo =71 47'; 2Poo : 2Poo = 110 42'. Cleavago 
 moderately easy parallel to ooP, less so parallel to 2P oo. It is sometimes found in 
 twin-crystals, the face of combination being ooP (Kopp's Krystallographie, p. 261) ; 
 rarely fibrous ; often granularly massive and compact. Specific gravity 6-465 to 6*480. 
 Hardness 3 to 3 -5, in some earthy varieties as low as 5 -4. Colourless when pure, tran- 
 sparent or translucent in various degree and with adamantine lustre. Fracture conchoi- 
 dal. Very brittle. White lead ore is found in Cornwall and Cumberland, at Lead! li 11s 
 and Wanlockhead in Scotland, in Siberia, in the Harz, in Bohemia, and many other 
 localities. It sometimes occurs altered to phosphate of lead by the action of water 
 containing phosphate of calcium ; to galena by the action of sulphuretted hydrogen, 
 and to minium by oxidation; also more or less to magnesite, malachite, and chryso- 
 colla. (Dana.) 
 
 Horn-lead or cerasine is a compound of carbonate and chloride of lead. 
 
 Hydrocarbonates. The precipitate formed in solutions of lead-salts by alkaline 
 carbonates varies in composition according to the temperature and concentration of tho 
 liquids. According to Berzelius, the anhydrous metacarbonate is obtained by treating 
 nitrate of lead with excess of carbonate of ammonia; according to Lefort (J. Pharin. 
 [3] xv. 26), by precipitating with alkaline carbonates in the cold, whereas from hot 
 solutions a hydrated salt, 3Pb 2 O.C0 3 .H 2 0, is. obtained. According to II. Kose (Ann. 
 Ch. Pharm. Ixxx. 235), the precipitate always contains hydrate of lead. Equivalent 
 quantities of nitrate of lead and neutral carbonate of sodium in cold strong solutions yield 
 the compound 6Pb 2 C0 3 .2PbHO + aq., which gives off some of its water at 100 C., 
 and takes up more carbonic acid; with cold dilute, or hot concentrated solutions, the 
 compound 5Pb 2 C0 3 .2PbIIO is obtained, and with hot dilute solutions 3Pb 2 C0 3 .2PbHO. 
 When the carbonate of sodium is added in excess, the precipitate consists chiefly of 
 Pb 2 C0 3 .PbIIO or (Pb 3 H)C0 4 , but contains a small quantity of soda. 
 
 Hydrated carbonates of lead are also formed by the direct action of carbonic acid on 
 hydrate of lead, and the compounds thus obtained differ from the precipitated carbo- 
 nate, in being amorphous and perfectly opaque, whereas the precipitated carbonate is 
 an aggregate of minute transparent crystalline grains. Hence the carbonate formed by 
 absorption of carbonic acid is much better adapted for a pigment, and is extensively used 
 as such under the name of white lead or ceruse ; its great opacity gives it that quality 
 which painters call body, enabling a small quantity of it to form a brilliant white coat- 
 ing over a considerable surface. 
 
 There are two methods of prepared white lead. In the older, called the Dutch 
 method, because it was originally practised in Holland, thin sheets of lead are placed 
 over gallipots containing weak acetic acid (water with about 2^ per cent of the strong 
 acid), the pots being embedded in fermenting tan, the temperature of which varies from 
 140 to 150 F. The action is often very rapid, the metal disappearing in a few weeks 
 to th centre of the sheet. In this process from 2 to 2 tons of lead (4480 to 5600 Ibs. 
 are converted into carbonate by a quantity of vinegar containing not more than 50 Ibs. 
 of strong acetic acid. It is evident, therefore, that the metal is neither oxidised nor 
 carbonated at the expense of the acetic acid. The oxygen is derived from the air, and 
 the carbonic acid from the fermenting tan ; the acetic acid merely serves to dissolve the 
 oxide of lead and convert it into a basic acetate, which is easily decomposed by car- 
 bonic acid, the acetic acid being thereby set free to act upon another portion of oxide 
 of lead. That this is really the mode of action, is shown by what takes place in the 
 more modern process, in which oxide of lead (litharge) is mixed with water and about 
 1 percent, of neutral acetate of lead, and carbonic acid gas is passed over it: in this 
 manner the oxide is quickly converted into excellent white lead. Nitrate of lead has 
 also been used in this latter process in place of the acetate. 
 
 White lead is a mixture or compound of carbonate and hydrate of lead, in various 
 proportions. Mulder (Ann. Ch. Pharm. xxxiii. 242), from the analysis of numerous 
 samples, concluded that there are three varieties of it, viz. : Pb 2 CO 3 .PbHO ; 5Pb 2 C0 3 . 
 6PbHO, and 3Pb 2 C0 3 .2PbHO. J. A. Phillips (Chem. Soc. Qu. J. iv. 165) found 
 the composition of four samples to agree with the first of these formulae, one with the 
 third, and another to contain 5Pb 2 C0 3 .2PbIIO. 
 
 White lead is often mixed with heavy spar and gypsum, the addition of which 
 renders it less liable to be blackened by the action of sulphuretted hydrogen. Oxide 
 
CARBONATES. 787 
 
 of zinc is likewise added for the same purpose. (Gm. iv. 127. Ure's Dictionary of 
 Arts, Manufactures and Mines, iii. 1015 ; Graham's Chemistry, 2nd edition, ii. 120.) 
 
 Acid Carbonate. Carbonate of lead dissolves slightly in water containing carbonic 
 acid ; the solution contains from ^^ to ^^ of lead-oxide, is rendered turbid by alka- 
 line carbonates, and coloured brown by sulphuretted hydrogen. (See LEAD.) 
 
 Carbonate of Lead and Sodium. 4Pb 2 C0 3 .Na 2 C0 3 . Produced, according to 
 Berzelius (Pogg. Ann. xlvii. 199), when nitrate of lead is precipitated by carbonate 
 of sodium, the precipitate boiled in the alkaline liquid, then washed and dried at 
 160 C. 
 
 CARBONATE OF LITHIUM, Li 2 C0 3 . This salt, which is slightly soluble in water, 
 exists in the waters of Carlsbad, Franzensbad, and others. It is prepared by dissolv- 
 ing an excess of carbonate of ammonia in a concentrated solution of chloride of lithium, 
 and washing the resulting precipitate with alcohol ; or by precipitating sulphate of lithium 
 with acetate of barium, evaporating the filtrate, and decomposing the residual acetate 
 of lithium by ignition. The salt melts at a low red heat, and solidifies to a vitreous 
 mass on cooling. It is not decomposed by heat. It dissolves in 100 pis. of cold 
 water (Vauquelin); in 130 pts. at 13 C., and in 128'5 pts. at 100 (Kremers 
 Jahresber. d. Chem. 1856, p. 275). The saturated solution boils at 100 (Kremers 
 ibid. p. 294). The solution is alkaline, and deposits the salt by slow evaporation, in 
 small prisms. It decomposes the salts of ammonia, and gives up its carbonic acid 
 to caustic baryta and lime. 
 
 Water saturated with carbonic acid dissolves carbonate of lithium more freely than 
 pure water. 
 
 CARBONATES OF MAGNESIUM. The anhydrous metacarbonate, Mg 2 C0 3 , or 
 Mg' 2 O.CO-, occurs native as magnesitc, associated with serpentine and other magnesian 
 rocks. It is found in rhombohedral crystals, isomorphous with calcspar. Eatio of the 
 principal axis to the secondary axes = 0*81 17 : 1. Angle of the terminal edges = 
 107 25. Cleavage perfect parallel to the rhombohedral faces. It also occurs massive, 
 granular, or fibrous, sometimes in radiating groups; also very compact. Specific 
 gravity = 2*8 to 3. Hardness = 3'5 to 4*5. It is white, or with various shades of 
 yellow, grey, and brown, has a vitreous or silky lustre, and exhibits all degrees of 
 transparency, down to complete opacity. Fracture flat, conchoidal. It is infusible 
 before the blowpipe, and dissolves slowly and with little effervescence in acids. It 
 occurs nearly pure, with only small quantities of water and the carbonates of 
 iron, manganese, and calcium, in Moravia, Styria, Silesia, Piedmont, Spain, and at 
 several localities in the United States. Carbonate of magnesium occurs also associated 
 in various proportions with the carbonates of iron, manganese, and calcium, forming 
 the minerals spheerosiderite, diallogite, dolomite, bitter spar, &c. 
 
 Anhydrous metacarbonate of magnesium cannot be prepared by precipitating a so- 
 luble magnesium -salt with an alkaline carbonate, as the precipitate thus formed always 
 contains hydrate of magnesium ; but by suspending the washed precipitate in water, 
 passing carbonic acid gas through the liquid till the precipitate is dissolved, and eva- 
 porating the solution by heat, the anhydrous salt is obtained as a crystalline powder, 
 which when examined by the microscope, exhibits the form of arragonite (H. Kose f 
 Pogg. Ann. xlii. 366). It is likewise obtained by heating sulphate of magnesium with 
 carbonate of sodium, to 160 C. in a sealed tube, or by enclosing a soluble magnesium- 
 salt, together with an alkaline dicarbonate supersaturated with carbonic acid, in a 
 strong vessel closed by a cork, through which the carbonic acid can escape slowly. 
 By this last method, it is obtained in microscopic rhombohedrons, like native magnesite 
 (Senarmont, Compt. rend, xxviii. 693; Ann. Ch. Phys. [3] xxx. 129). Anhydrous 
 carbonate of magnesium is therefore isodimorphous with carbonate of calcium. When 
 moistened with water, it gives an alkaline reaction with litmus and violets. If the 
 solution of carbonate of magnesium in excess of carbonic acid be left to evaporate 
 spontaneously, or kept fcr some time at 50 C., it deposits small hexagonal prisms, 
 containing Mg 2 C0 3 + 3 aq. : they give up their water in warm air, becoming opaque, 
 but retaining their form. The same hydrated crystals are obtained by mixing the 
 solutions of sulphate of magnesium and sesquicarbonate of potassium and sodium, and 
 leaving the mixture to stand. A saturated solution of carbonate of magnesium in 
 aqueous carbonic acid, exposed for so"me time to a winter temperature, deposits 
 transparent oblique prismatic crystals, containing 5 at. water : Mg 2 C0 3 + 5 aq. They 
 are converted into the preceding, with loss of transparency, by exposure to the air, 
 more quickly in sunshine, and by immersion in water at 50 C. If boiled with water, 
 they give up part of their carbonic acid, and are ultimately converted into 2Mg 2 CO s . 
 MgHO + 2aq. (Fritzsche.) 
 
 Hydrocarbonates. a. 5Mg 2 0.4C0 2 n- 5aq. = 2Mg 2 C0 3 .MgHO + 2 aq. = (Mg 5 H 3 )C 2 8 
 + aq. Produced, as just mentioned, by the action of water on Mg 2 CO 3 + 5 aq., better by 
 
 3 E 2 
 
788 CARBONATES. 
 
 boiling with water containing ammonia (Fritzsche); also by precipitating sulphate 
 of magnesium with carbonate of sodium, and drying the precipitate at 100 C. (H. Rose, 
 Ann. Ch. Pharm. Ixxx. 234) ; also, according to Berzelius, by boiling a solution of acid 
 carbonate of magnesium for a long time. It is a white granular powder. 
 
 b. 4Mg 2 0.3C0 2 + 4aq. = 3Mg 2 CO s .2MgHO + 3 aq. = (Mg 8 H 4 )C 3 12 + 2aq. Found 
 native as Hydromagnesite , in small white, brittle, or acicular crystals, of the monoclinic 
 system, or in chalky crusts. Specific gravity = 2-145 to 2'18. Hardness of the crys- 
 tals = 3'5. It is found at Hrubschitz in Moravia in serpentine ; in Negroponte near 
 Kumi ; and crystallised with serpentine and brucite (hydrate of magnesium), in Lan- 
 caster county, Pennsylvania. Lancasterite is a mixture of brucite and hydromagnesite. 
 (Dana, ii 456.) 
 
 A substance of the same composition is obtained by mixing sulphate of magnesium 
 with excess of a hot solution of carbonate of potassium, and boiling the precipitate 
 with fresh quantities of water, as long as any acid carbonate dissolves out (B erz eliu s) ; 
 also, according to Fritzsche, by boiling a saturated solution of the acid carbonate, and 
 twice boiling the resulting precipitate with fresh quantities of water. It is a white 
 powder, slightly soluble in water, and forming an alkaline solution. When dried at. 
 100 C. in the air, it absorbs carbonic acid, and is converted into 5Mg 2 0.4C0 2 + 5aq. 
 (H. Eose.) 
 
 c. 3Mg 2 O.2C0 2 + 3aq. (?) Obtained, according to Fritzsche (Pogg. Ann. xxxvii. 
 310), by precipitating sulphate of magnesium with a very large excess of carbonate of 
 sodium, boiling the whole till the precipitate passes from the flocculent to the granular 
 condition ; then washing and boiling rapidly with water, pouring off the liquid, and 
 twice boiling the residue with fresh water. It consists of small grains mixed with a 
 small quantity of the original flocculent precipitate. According to Berzelius, the pre- 
 cipitate obtained as above may contain carbonate of sodium. According to H. Rose, the 
 precipitate formed by carbonate of sodium with sulphate of magnesium always contains 
 5Mg'-0 to 4C0 2 , whatever may be the temperature and strength of the solutions. 
 
 The pharmaceutical preparation known as Magnesia alba, is a mixture of the several 
 hydrocarbonates of magnesium, the proportions depending on the relative quantity of 
 the precipitant, the degree of dilution, and the temperature at which precipitation 
 takes place. It is prepared on the large scale by precipitating sulphate, nitrate, or 
 chloride of magnesium with carbonate of potassium or sodium. Various mineral 
 waters containing sulphate of magnesium, such as the Epsom water, are used for the 
 purpose, also the mother-liquor of sea- water, of many salt-springs, and of many kinds 
 of saltpetre ; most of these liquids, however, contain lime, which must be previously 
 separated by sulphate of potassium or sodium. After being well washed with ' hot 
 water, it forms a very light, and bulky powder. The utmost degree of lightness is ob- 
 tained by allowing the precipitate to freeze while still moist. (Gm. iii. 228.) 
 
 Acid Carbonate. Magnesia alba shaken up with aqueous carbonic acid, forms a 
 solution^ having a bitter taste and alkaline reaction, and containing, according to Sou- 
 beiran, just twice as much carbonic acid with the same quantity of magnesia as the 
 normal salt (probably MgHCO 3 ). It becomes turbid at 75 C., but recovers its clearness 
 on cooling. When heated to 50 C., or evaporated in vacuo, it deposits the tribydrated 
 metacarbonate, Mg 2 C0 3 + 3aq. (Berzelius, Fritzsche.) 
 
 Carbonate of Magnesium and Ammonium, Mg(NH 4 )CO s + 2H 2 0, crys- 
 tallises in translucent rhombohedrons from a mixture of the cold aqueous solutions of 
 sulphate or chloride of magnesium and sesquicarbonate of ammonia, the latter in 
 excess, or from a solution of hydrate of magnesium in sesquicarbonate of ammonia. 
 
 Carbonate of Magnesium and Potassium, (Mg 4 K 2 H 2 )C 4 12 + 8 aq., is de- 
 posited after a few days in large crystals from a cold aqueous mixture of chloride or 
 nitrate of magnesium with excess of diacid carbonate of potassium. The crystals become 
 opaque and lose water at 100 C., and are decomposed by water, which dissolves the 
 acid carbonates of potassium and magnesium, and leaves a residue consisting of the 
 hydrocarbonate 3Mg 2 C0 3 .MgHO + 3 aq. (B erzelius.) 
 
 H. Deville (Ann. Ch. Phys. xxxiii. 75), obtained the salt by the same process in 
 microscopic crystals, apparently having the form of oblique rhombic prisms. By using 
 sesquicarbonate of potassium instead of the diacid carbonate, he obtained, together with 
 the preceding, another double salt, containing MgHCO 3 + 2aq. The latter is obtained 
 separately in small rhombic prisms by digesting magnesia alba for twelve or fifteen 
 hours at 60 or 70 C., with diacid carbonate of potassium. 
 
 Carbonate of Magnesium and Sodium, MgNaCO 3 , is obtained in anhydrous 
 microscopic crystals by digesting magnesia alba in like manner with diacid carbonate of 
 sodium. A mixture of a magnesium-salt with diacid carbonate of sodium yields no 
 double salt, but only Mg 2 CO ;J + 3 a q. 
 
 CABBONATE OF MANGANESE. The anhydrous carbonate occurs native as Di- 
 
CARBONATES. 789 
 
 allogitc, also called "Red Manganese, Rhodochrosite, Brown Spar, Manganspath. It 
 forms rhombohedral crystals, isomorphous with calcite, in which the principal is to 
 the secondary axes as 0-8117 : 1, and the inclination of the faces meeting in the terminal 
 edges = 106 51'. The crystals are tabular, exhibiting the faces K . -K oo B . OK. 
 It occurs also in globular and botryoi'dal forms ; likewise granular massive ; occasionally 
 as an impalpable powder. Specific gravity 3'4 to 3'6 ; of a variety from Kapnik, 3'592, 
 Hardness 3'5 to 4-5. It is translucent, of rose-red or brownish colour, and vitreous lustre 
 inclining to pearly. Streak white. Fracture uneven. Brittle. It is found in the Saxou 
 mines, at Nagjay and Kapnik, in Transylvania, near Elbingcrode in the Harz, &c. At 
 GMendree in the county of Clare, Ireland, it forms a layer of yellowish-grey colour, 
 two inches thick, below a bog. It also occurs in the pulverulent form, coating triplit?, 
 at Washington, Connecticut. It is generally mixed with the carbonates of calcium 
 and magnesium, the proportion of carbonate of manganese varying from 97 to 75 per 
 cent. A sample from Ireland, analysed by Grruner (Ann. Min. [3] xviii. 61), gave 
 97'1 per cent. Mn 2 C0 3 , 07 Fe-CO 3 , 1-0 Ca 2 CO s , 0'8 Mg 2 C0 8 , and p'l Mn 4 3 . 
 
 Anhydrous carbonate of manganese may be obtained artificially as a very fine 
 amorphous, faintly rose-coloured powder, by heating chloride of manganese in a sealed 
 tube with carbonate of sodium to 160 C., or with carbonate of calcium to 140 170 
 from 12 to 48 hours. (Senarmont, Compt. rend, xxviii. 693.) 
 
 By precipitating manganous salts with carbonate of potassium or sodium, a white 
 precipitate is formed, which, after washing with boiling water, and drying in vacuo 
 over oil of vitriol, is a snow-white tasteless powder, containing, according to the 
 analyses of Ure, Turner, John, and Forchhammer, 2Mn 2 C0 3 + aq, (G-m. iv. 214). 
 According to H. Eose (Ann. Ch. Pharm. Ixxx. 235) equivalent quantities of chloride 
 of manganese and carbonate of sodium yield a precipitate containing 5Mn 2 C0 3 .2MnHO. 
 
 Carbonate of manganese, whether anhydrous or hydrated, is permanent at ordinary 
 temperatures, but when heated to redness in the air, assumes a dark brown colour, and 
 is converted into manganoso-manganic oxide. Ignited in an atmosphere of hydrogen, 
 it yields greenish-grey manganous oxide. Ignited in chlorine gas, it yields, according 
 to Wohler. a crystalline mixture of chloride of manganese and manganoso-manganic 
 oxide : 
 
 4Mn 2 C0 3 + Cl 2 = 2MnCl + 2Mn 3 2 + 4C0 2 . 
 
 Chlorine-water or aqueous hypochlorite of calcium converts it, first into manganoso- 
 manganic oxide, afterwards into peroxide. When recently precipitated, it dissolves in 
 ammoniacal salts. It is soluble in 7680 pts. of pure water, and in 3480 pts. of aqueous 
 carbonic acid. (John.) 
 
 CARBONATES OF MERCURY. Mercuric nitrate gives with neutral or acid car- 
 bonate of potassium or sodium, a brown-red precipitate, containing 4Hg 2 O.C0 2 , or 
 3Hg 2 O.Hg s C0 3 (Setterberg, Pogg. Ann. xix. 60.) From mercuric chloride, alkaline 
 bicarbonates precipitate, not a carbonate but an oxychloride. 
 
 Mercurous nitrate yields with carbonate of potassium, a black or yellow powder, 
 consisting of mercurous carbonate, Hhg 2 C0 3 . It is very apt to give off carbonic acid ; 
 and the best way of obtaining it of definite composition is to mix mercurous nitrate 
 with a slight excess of alkaline bicarbonate, set the mixture aside for a few days, and 
 stir it frequently, then wash as quickly as possible, and dry in vacuo over oil of vitriol 
 (Setterberg, loc. cit.) It is converted into mercuric oxide by exposure to the air. 
 Alkalis blacken it, separating metallic mercury. (Grin. vi. 15.) 
 
 CARBONATE OF METHYL. See CARBONIC ETHERS. 
 
 CARBONATE OF NICKEL. The anhydrous salt, Ni 2 C0 3 , is obtained by heating 
 chloride of nickel with alkaline carbonates in sealed tubes, in the same manner as car- 
 bonate of cobalt (p. 782), is a greenish- white crystalline powder, composed of minute 
 rhombohedrons, scarcely attacked by strong acids at ordinary temperatures. (Senar- 
 mont.) 
 
 A hydrocarhonate of nickel, Ni 2 C0 3 .4NiH 3 2 , called Emerald-nickel, occurs in the 
 form of a stalactitic crust on chrome-iron ore, at Texas, Lancaster County, Pennsylvania, 
 also at Swinaness in Unst, Shetland. It is amorphous, with an uneven somewhat scaly 
 fracture. Specific gravity = 2'67 to 2 '623. Hardness 3 to 3 '25. Colour, emerald- 
 green with strong vitreous lustre. Streak green. It gives off water when heated, and 
 turns blackish. (B. Silliman, Jun. Sill. Am. J. [2] vi. 248.) 
 
 Hydro-nickelmagnesite, a mineral allied to the preceding, but containing magnesium 
 as well as nickel, is found in the same localities in serpentine. (Shepard ibid. 250.) 
 
 Nickel-salts treated with alkaline carbonates, yield a pale apple-green, flocculent 
 precipitate, which, after washing and drying, sometimes forms a loose, earthy, pale- 
 green mass having a faint metallic lustre, sometimes, especially after continued wash- 
 ing with boiling water, a thick blackish-green mass, having a conchoidal wavy fracture. 
 The precipitates thus formed always contain water, their composition varying according 
 
 3 E 3 
 
790 CARBONATES. 
 
 to the temperature, strength, and proportions of the solutions employed. According to 
 H. Kose (Ann. Ch. Pharm. Ixxx. 237), the precipitate formed in the cold with sulphate 
 t>f nickel and neutral carbonate of sodium consists, 'when dried at 100 0., chiefly of 
 Ni 2 C0 3 .3NiHO + 2aq. ; if boiled with a large quantity of water, it appears to take 
 up water and lose carbonic acid. If heated in the air above 100, it gradually gives 
 off carbonic acid and water, and is partly converted into peroxide of nickel. Preci- 
 pitated carbonate of nickel does not appear to be altered by digestion with bicarbonate 
 of soda, even at 60 to 70. (H. Deville.) 
 
 Carbonates of Nickel and Potassium. By methods similar to those adopted with 
 the corresponding cobalt-salts (p. 782), Deville obtained the salt (NiK)CO 3 + 2aq. in 
 shining apple-green microscopic needles, and (Ni 2 KH)C 2 6 -f-4aq., in light green 
 crystals, apparently having the form of oblique rhombic prisms. The last was also ob- 
 tained by Rose. 
 
 Carbonate of Nickel and Sodium, (NiNa)C0 8 + 5aq., is obtained like the cobalt-salt, 
 in small crystals, which appear to be cube-like rhombohedrons. (Deville.) 
 
 CAKBONATES OF PALLADIUM. On adding an alkaline carbonate to a solution of 
 palladium, a light yellow precipitate is formed, at first without evolution of carbonic 
 anhydride; but on continuing the precipitation, effervescence ensues, and the precipitate 
 turns brown. It retains a small quantity of carbonic acid when dry. (Berzelius.) 
 
 CARBONATES OF POTASSIUM. Three of these salts are known, all having the 
 constitution of metacarbonates, viz. the dipotassic or neutral carbonate, K 2 C0 3 or 
 K 2 O.C0 8 , the monopotassic or di-acid carbonate, commonly called bicarbonate, KHCO" 
 or K 2 O.H 2 0.2C0 2 , and the tetrapotassic or sesqui-acid carbonate, K'H 2 C 3 9 , or 
 2K*0.3CO + H 2 0. The last has not been obtained in very definite form, and is 
 perhaps only a mixture of the other two. 
 
 Dipotassic Carbonate, or Neutral Carbonate of Potassium. K 2 C0 3 . Sub- 
 carbonate of Potash. Mild or Aerated Vegetable Alkali. Salt of Tartar. Purified Potash. 
 Pcarlash. Alkali vcgetabile fixum. Cineres clavellati dcpurati. This salt is obtained 
 chiefly from the ashes of plants. Living plants contain the potassium-salts of several 
 vegetable acids, acetic, malic, tartaric, oxalic, &c. ; and these salts, when calcined, are 
 transformed into carbonate, which remains in the calcined residue mixed with charcoal 
 and the various mineral salts contained in the plant, viz. sulphate, chloride, and 
 silicate of potassium and sodium, besides carbonate of calcium and other insoluble 
 matters. On treating the ash with water, the carbonate of potassium is dissolved, 
 together with the alkaline sulphates and chlorides, and a residue is left, consisting of 
 carbonate and phosphate of calcium, silica, clay, &c. The solution is evaporated to 
 dryness, and the residue is sold as crude potash. Sometimes lime is stirred in with 
 the solution during the evaporation, and then the carbonate of potassium is partly con- 
 verted into hydrate or caustic potash. The quantity of potash obtained from diffe- 
 rent plants varies according to their nature, the most, succulent yielding the largest 
 amount, inasmuch as the alkaline salts are chiefly contained in the sap: hence herbaceous 
 plants yield more than shrubs or trees. The different parts of the same plant also 
 yield different quantities the leaves more than the branches, the bark more than the 
 wood. 
 
 The ashes of plants are used in all countries for the alkali which they contain, both 
 as manure for the soil, and to yield a lye for the bleaching of linen ; but it is only in 
 countries where wood is very abundant, that potash can be advantageously prepared as 
 a commercial product. Nearly all the potash used in the arts comes from America or 
 from Russia. 
 
 Crude potash contains from 60 to 80 per cent, of carbonate of potassium, the re- 
 mainder consisting of sulphate, chloride, and small quantities of silicate of potasssium 
 together with organic matter which has not been completely burnt. This carbonate 
 being much more soluble than the other potassium-salts, may, for the most part, be 
 separated from them by digesting the crude potash for several days with its own weight 
 of cold water, then decanting the liquid, quickly evaporating it, removing it from the fire 
 as soon as it begins to show turbidity from the formation of small crystals, and leaving it 
 to cool, stirring all the while to prevent the formation of large crystals, which would 
 enclose mother-liquor in their cavities. The mother-liquor is then filtered off, the 
 crystals washed with a small quantity of solution of pure carbonate of potassium, then 
 dried and heated to incipient redness in vessels of cast-iron, silver, or platinum. The 
 product thus obtained, called pearlash, contains only 2 or 3 per cent, of foreign 
 matter, which, however, is difficult to remove. 
 
 Pure carbonate of potassium may be obtained by igniting acid tartrate of potassium 
 (cream of tartar) in a crucible. A black residue is thereby obtained, consisting of 
 carbonate of potassium and charcoal, which is often used as a reducing agent, nii'ln- 
 the name of black flux. The carbonate of potassium is separated from the charcoal ly 
 
CARBONATES. 791 
 
 isolation in water, filtration, and evaporation. If the solution lias a "brown colour from 
 undecomposed organic matter, the salt must be again ignited. 
 
 Carbonate of potassium is sometimes prepared by throwing into a red-hot iron 
 vessel, by small portions at a time, a mixture of 1 pt. cream of tartar and 2 pts. nitre. 
 The carbon of the cream of tartar is then all burnt away by the oxygen of the nitre, 
 and there remains a white mass called white flux, consisting almost wholly of carbonate 
 of potassium. It frequently, however, contains small quantities of nitrite, which may 
 be avoided by diminishing the proportion of nitre used, and always a little cyanide 
 of potassium. 
 
 Pure carbonate of potassium is, however, more easily obtained from the acid car- 
 bonate or oxalate (binoxalate). The acid carbonate, KHCO 3 , is found in commerce in 
 large crystals very nearly pure. It may be further purified by recrystallisation, and, 
 when ignited in a platinum or silver crucible, yields the pure neutral carbonate. The 
 acid oxalate of potassium may be prepared by mixing hydrate of potassium with excess 
 of oxalic acid, and purified by several crystallisations. When ignited, it leaves pure 
 carbonate of potassium unmixed with charcoal. (Eegnault.) 
 
 The impurities which may occur in commercial carbonate of potassium are the fol- 
 lowing : Sulphate of potassium : detected by the turbidity produced on adding chloride 
 of barium to the solution acidulated with hydrochloric acid and diluted. Chloride of 
 potassium : cloud produced by nitrate of silver in the solution acidulated by nitric 
 acid. Phosphate of potassium : crystalline precipitate by sulphate of magnesium in 
 solution treated first with hydrochloric acid, then with excess of ammonia. Nitrate or 
 nitrite of potassium : reddish brown colour by ferrous sulphate in solution of the salt 
 in excess of sulphuric acid. Cyanide of potassium : Prussian blue, formed by ferroso- 
 ferric sulphate and excess of hydrochloric acid. Soda : crystalline precipitate with 
 acid metantimonate of potassium (p. 327). Carbonate of calcium : retained in solution, 
 partly through the medium of the carbonate of potassium : cloud with oxalic acid after 
 neutralisation with acetic acid. Silica : remains undissolved on acidulating with 
 hydrochloric acid, evaporating to complete dryness, and digesting the residue in dilute 
 hydrochloric acid. Oxide of copper : red-brown precipitate with ferrocyanide of potas- 
 sium in acidulated solution. 
 
 Carbonate of potassium is very soluble in water, 1 pt. of the anhydrous salt dis- 
 solving, according to Osann, in 1-05 pt. of water at 3 C. (37'4 F.), in 0-9 pt. at 12-1 C. 
 (54 F.), and in 0'49 pt, at 70 C. (158 F.) The most concentrated solution, contain- 
 ing 48'8 per cent, of the anhydrous salt, has a specific gravity of 1*54 at 15 C., and 
 boils at 113 C. (235-4 F.) (Dalton). It has a strong alkaline taste and reaction, but 
 is only slightly corrosive. A highly concentrated hot solution deposits on cooling 
 rhombic octahedrons containing 20 per cent, of water, corresponding to the formula 
 K-C0 3 + 2aq. 
 
 Both the crystals and the anhydrous salt deliquesce rapidly in the air, forming an 
 oily liquid. The anhydrous salt melts at a red heat, volatilises at a white heat. It is 
 not decomposed by any temperature in close vessels ; but at a red heat, not sufficient 
 to melt it, it is partly decomposed and converted into hydrate by a stream of aqueous 
 vapour or moist air ; it is not decomposed by dry air or dry hydrogen gas. Charcoal, at 
 a bright red heat, decomposes it, with separation of potassium and formation of car- 
 bonic oxide and other products (see POTASSIUM). The aqueous solution, containing 
 not less than 10 pts. of water to 1 pt. of the dry salt, is decomposed by lime at ordi- 
 nary temperatures, and more quickly at the boiling heat, the carbonic acid being re- 
 moved and caustic potassa produced. "With more concentrated solutions, the reverse 
 action takes place, caustic potassa abstracting carbonic acid from carbonate of calcium. 
 
 Carbonate of potassium is much used in chemical manufactures, especially for the 
 preparation of soft soap, in glass making, and in the preparation of cyanide of potas- 
 sium, ferrocyanide of potassium, Prussian blue, &c. ; also for the preparation of nitrate 
 of potassium from the nitrates of sodium, magnesium, and calcium. 
 
 Monopotassic Carbonate, or Di-acid Carbonate of Potassium. KHCO 3 = 
 K 2 O.H 2 0.2C0 2 . Bicarbonate of Potassa. Bertholkf s neutral Carbonate of Potassa. 
 This salt is obtained by passing carbonic acid gas to saturation into a solution of 1 pt. 
 of the commercial neutral carbonate in 4 or 5 pts. of water. Crystals of the acid car- 
 bonate soon form, and may be pm'ified by washing with a small quantity of cold water. 
 If a flocculent precipitate should form at first, consisting of alumina or silica, it must 
 be removed by filtration. The carbonic acid evolved in alcoholic fermentation, or that 
 which in some localities escapes from the soil, Inay be utilised for this purpose. A 
 very good way of preparing the acid carbonate is to expose the mixture, of neutral car- 
 bonate and charcoal, obtained by calcining cream of tartar and slightly moistened with 
 water, to the action of carbonic acid gas ; the presence of the charcoal greatly facili- 
 tates the absorption of the carbonic acid. The acid carbonate is dissolved out from 
 
 S E 4 
 
792 CARBONATES, 
 
 the charcoal by boiling water and left to crystallise (Wohler, Ann. Ch. Pliarm. xxiv. 
 49). It must not be boiled in iron vessels, as it would dissolve a small quantity of the 
 iron. 
 
 Acid carbonate of potassium crystallises in large rhomboi'dal prisms belonging to 
 the monoclinic system. Katio of orthodiagonal to clinodiagonal to principal axis = 
 0-3734 : 1 : 0*491. Inclination of clinodiagonal to principal axis = 76 35'. The 
 crystals often exhibit the faces ooP.OP.ooPoo.-Poo. + 2P oo (fig. 125), the face 
 P oo frequently predominating so far as to obliterate 
 Fig. 125. the adjacent faces. ooP : oo P = 138. Cleavage 
 
 parallel to ooPoo, -Poo, and OP. The crystals con- 
 tain no water of crystallisation. When heated to 
 100 C., they give off water and carbonic anhydride, 
 and are reduced to neutral carbonate : 2KIICO 3 - IPO 
 -CO 2 = K 2 C0 3 . 
 
 Acid carbonate of potassium is much less soluble in 
 water than the neutral carbonate. 100 pts. of water 
 dissolve of it, according to Poggiale : 
 
 19-61 pts. At 50 C. . . . 37-92 pts. 
 
 23-33 60 ... 41-35 
 
 26-91 70 ... 45-24 
 
 The aqueous solution when boiled gives off carbonic acid, and is gradually changed 
 into neutral carbonate. The decomposition is sufficiently slow to admit of the puri- 
 fication of the acid carbonate from a boiling solution without much loss. 
 
 It dissolves but sparingly in boiling alcohol, only indeed to the amount of 1 pt. in 
 1200. 
 
 The aqueous solution of acid carbonate of potassium, mixed with the salts of other 
 metals, generally forms double carbonates (pp. 782 788). It does not precipitate mag- 
 nesium-salts in the cold, a character by which it is readily distinguished from the neutral 
 carbonate. 
 
 Acid carbonate of potassium is much, used in chemical operations where a pure 
 potassium-salt is required, as it is very easily obtained in a pure and definite state. It 
 is also used in medicine, in cases of gout and uric acid gravel. 
 
 Sesquicarbonate of Potassium ? A salt intermediate in composition between the two 
 preceding, was said by Berthollet to be obtained in crystals, by mixing 100 pts. of the 
 neutral with 131 pts. of the acid carbonate (1 at. K 2 C0 3 with 2 at. KHCO 3 ), or by 
 heating a solution of the di-acid carbonate as long as carbonic acid goes off; but ac- 
 cording to H. Hose (Pogg. Ann. xxxiv. 149), the latter process yields almost pure 
 neutral carbonate of potassium. The salt prepared by the first process should contain 
 K 4 H 2 C 3 9 , or 2K 2 0.3C0 2 + H 2 ; but its existence does not appear to have been satis- 
 factorily proved. 
 
 CAEBONATE OF SILVEB, Ag 2 C0 3 , is produced by precipitating nitrate of silver 
 with an alkaline carbonate. It is white at first, but becomes yellow when the soluble 
 salts are washed out, and blackens when exposed to light or gently heated. It dissolves 
 readily in strong ammonia, and the solution treated with absolute alcohol yields a pre- 
 cipitate containing ammonia and carbonate of silver. (Berzelius.) 
 
 At 200 C. it gives off carbonic anhydride, and leaves pure oxide of silver, which 
 begins to give off oxygen at 250. By precipitating nitrate of silver with a large excess 
 of alkaline carbonate and boiling, a basic carbonate is obtained, having, when dried at 
 100, the composition 3Ag 2 O.CO' 2 , or Ag 2 C0 3 .2Ag 2 0, perhaps only a mixture. (H. E o s e, 
 Ann. Ch. Pharm. Ixxxiv. 202.) 
 
 CARBONATES OF SODIUM. Three of these salts are known, corresponding in 
 composition to the potassium salts. 
 
 Disodic Carbonate, or Neutral Carbonate of Sodium, Na 2 CO*. Subcar- 
 bonate of Soda. Soda. Mild mineral alkali. Alkali minerale fixum. This salt exists in 
 the soda-lakes of Egypt and Hungary, and in the volcanic springs of Iceland, &c. ; it 
 also frequently occurs, mixed with sulphate of sodium, in the form of an efflorescence 
 on walls, being formed from sodium-salts contained in the mortar. It is largely used 
 in the arts, and was formerly obtained from barilla, the ash of Salsola soda and other 
 plants growing on the sea-shore, and from the ash of sea-weed called kelp : but at the 
 present day, nearly all the soda of commerce is obtained from common salt, by a process 
 invented by Leblanc, towards the end of the last century, and perfected by D'Anfret 
 and D'Arcye. This process consists of three stages : 
 
 1. The conversion of chloride of sodium into sulphate by heating it with sulphuric 
 acid. 
 
 2. The conversion of the sulphate into carbonate by heating it in a reverbcratory 
 
CARBONATES. 793 
 
 furnace with chalk or limestone and coal. The materials are mixed in the proportion 
 of about 3 pts. of dry sulphate of sodium, 3 pts. chalk, and 2 pts. coal. The sulphate 
 of sodium is reduced to sulphide, with evolution of carbonic oxide ; and the sulphide 
 of sodium is converted by the carbonate of calcium into carbonate of sodium and sul- 
 phide of calcium, which, by taking up lime, is for the most part converted into an in- 
 soluble oxysulphide of calcium : 
 
 2Na 2 S0 4 + 3Ca 2 C0 8 + C 9 = 2Na 2 C0 3 + Ca 6 S 2 + 10CO. 
 
 Part of the carbonic acid is, however, driven off from the lime by the heat, before it 
 can act on the sulphide of sodium, and consequently, the fused mass contains, besides 
 carbonate of sodium, a variable but always large amount of caustic soda. 
 
 The crude soda obtained by this process, has the appearance of dark-grey, half- 
 vitrified balls, hence called "black balls," being brought into this form by 'stirring 
 while in the semi-fused state. It varies considerably in composition, as the following 
 analyses will show, one of a sample from Cassel analysed by linger, another from New- 
 castle, by Kichardson. 
 
 Composition of Black Balls, or Crude Soda. 
 
 Cassel. Newcastle. 
 
 Carbonate of sodium 23-57 9'89 
 
 Caustic soda 
 Sulphate of sodium 
 Chloride of sodium 
 Carbonate of calcium 
 Oxysulphide of calcium 
 Sulphide of iron 
 Silicate of magnesium 
 
 11-12 25-64 
 
 1-99 3-64 
 
 2-54 0-60 
 
 12-90 15-67 
 
 3476 35-57 
 
 2-45 1-22 
 
 4-74 0-88 
 
 Charcoal 1'59 4'28 
 
 Sand 2-02 0'44 
 
 Water 2-10 2-17 
 
 99-78 100-00 
 
 3. Purification. The crude or ball soda, after being crushed under millstones and 
 sifted, or loosened and disintegrated by hot vapour, is lixiviated with warm water, which 
 dissolves up the carbonate of sodium and the other soluble salts, leaving the oxysulphide 
 of calcium undissolved. To effect the extraction with the smallest possible quantity 
 of water, the crude soda is placed in perforated sheet-iron boxes, suspended just below 
 the surface of the liquid, and is subjected to a continuous process of exhaustion in a 
 series of lixiviating tanks, arranged somewhat like the pans for the evaporation of 
 boric acid (p. 637). Each box containing the crude soda is first suspended in the 
 lowest cistern, which contains a nearly saturated lye, then transferred to the next, 
 which contains a somewhat weaker lye, and so on till it arrives at the highest, into which 
 pure water is admitted from a cistern. "When the lye in the lowest tank is saturated, 
 it is transferred to the evaporating pan, its place being supplied by that in the next, 
 which in its turn is replaced by the third, &c. In this manner, each portion of liquid 
 gets thoroughly saturated, and the ball soda completely exhausted of soluble salts. 
 The concentrated solution is boiled down to dry ness, and yields a salt consisting chiefly 
 of carbonate of sodium mixed with caustic soda and sulphide. This is called soda- 
 salt. 
 
 4. To purify this product further, it is mixed with one-fourth of its bulk of sawdust, 
 and exposed to a low red heat in a reverberatory furnace, for about four hours : the 
 carbonic acid produced by the combustion of the sawdust, then converts the caustic 
 soda into carbonate; also the sulphide, with evolution of sulphuretted hydrogen. This 
 product contains about 50 per cent, of alkali, and forms soda-salt of the best quality. 
 
 5. To obtain crystallised carbonate, the purified soda-salt is dissolved in water, and 
 the liquid when clarified is boiled down till a pellicle forms on the surface. The solu- 
 tion is then run into shallow crystallising vessels, and after standing for a week, the 
 mother-liquor is drawn off, and the crystals are drained and broken up for the market. 
 The crystals thus obtained contain 10 at. of water. The mother-liquor, which contains 
 the foreign salts is evaporated to dryness for soda-salt. 
 
 The crystallisation of carbonate of sodium generally affords a safe guarantee of its 
 purity ; the crystals also dissolve in water much more quickly than the anhydrous salt, 
 and are therefore more convenient for many purposes. But when the salt is required 
 in the anhydrous state, as for glass-making, or as a flux in metallurgic operations, or 
 where large quantities are wanted, as in the soap-manufacture, the soda-salt is preferred, 
 as the large quantity of water in the crystals (nearly 63 per cent.) greatly increases the 
 cost cf transport. For some purposes, the crude soda as it leaves the furnace is suffi- 
 
794 CARBONATES. 
 
 ciently pure. In preparing it to be sold for such purposes, sulphate of sodium is used 
 containing 10 to 12 per cent, of common salt ; this remains unchanged in the soda, and 
 communicates to it the property of easily falling to pieces in damp air, thus obviating 
 the necessity of grinding. 
 
 For further details respecting the soda-manufacture, see Miller's Chemistry, vol. ii. ; 
 Ure's Dictionary of Arts, Manufactures, and Mines, iii. 720 ; Chemical Tech- 
 nology, by Richardson and Watts; Pay en, Precis de Chimie industridlc, 4 me ed. 
 i. 296. 
 
 Other methods of obtaining carbonate of sodium from the chloride have been pro- 
 posed, but none of them appear to be able to compete with that above described. 
 1. Sulphate of iron pi-oduced by the oxidation of iron pyrites, is a cheap article, and 
 has been proposed as a substitute for sulphuric acid in the first stage of the process : 
 sulphate of sodium and chloride of iron are formed, the latter volatilising ; or the two 
 salts are dissolved together in water, and the solution is exposed to a low temperature, 
 whereupon sulphate of sodium crystallises out, while chloride of iron remains in solu- 
 tion ; or the sulphate of sodium may be made to crystallise out by raising the liquor 
 to the boiling point. 2. Sulphate of sodium may be formed by roasting iron pyrites 
 in a reverberatory furnace with common salt. 3. Sulphate of sodium is decomposed by 
 a solution of caustic baryta or strontia, these earths being procured by decomposing 
 the native sulphates with steam at a red heat ; the sulphuric acid thereby set free 
 might be used for converting the chloride of sodium into sulphate (Tilghmann). 
 4. Chloride of sodium is decomposed by hot steam in presence of alumina, whereby 
 aluminate of sodium is formed; and the solution of this salt is decomposed by a 
 current of carbonic acid gas (Tilghmann). -5. Ammonia gas is passed into a solution 
 of chloride of sodium ; then carbonic acid, whereby chloride of ammonium and acid 
 carbonate of sodium are produced : 
 
 NaCl + NH 8 + CO 9 + H 2 = NaHCO 3 + NH 4 C1. 
 
 The acid carbonate of sodium being the less soluble salt of the two, crystallises out ; 
 it is converted into neutral carbonate by heat, and the carbonic acid evolved is used 
 again. The mother-liquor containing the sal-ammoniac is boiled, to drive off any car- 
 bonate of ammonium that it may contain, and this salt is collected ; the solution is then 
 boiled with lime, to liberate the rest of the ammonia. In this manner the operation 
 may be conducted with but little loss. (Schloessing and Eoland.) 
 
 The impurities found in commercial carbonate of sodium are, sulphide, hyposulphite, 
 sul.phate, chloride and fcrrocyanide of sodium; also potassium-salts, carbonate of 
 calcium, and carbonate of magnesium. It may be purified by repeated crystallisation, 
 or by washing the commercial crystals with cold water, dissolving them in hot water, 
 stirring and cooling rapidly, to prevent formation of large crystals, then draining 
 off the mother-liquor, and washing the crystalline powder with cold water. (Gray- 
 Lussac.) 
 
 Neutral carbonate of sodium in the anhydrous state, is a white powder composed of 
 
 translucent particles. It has a specific gravity of 2 - 4659 (Karstin). It melts at a 
 
 moderate red heat, more easily than carbonate of potassium. It is quite undecom- 
 
 posible by heat in close vessels, but is easily decomposed when heated to redness in a 
 
 current of steam or moist air, less easily in a current of dry air or hydrogen (H. Eose). 
 
 It is decomposed by charcoal at a bright red heat, yielding carbonic oxide and sodium. 
 
 In contact with water, it becomes heated, and forms a hydrate which dissolves. It 
 
 has an alkaline taste and reaction, but is even less caustic than 
 
 Fig. 126. carbonate of potassium. 
 
 Hydrates. There are several hydrates of neutral carbonate of 
 sodium. a. The ordinary crystals which separate from a mode- 
 rately strong solution at ordinary temperatures, contain 10 at, 
 (62-69 per cent.) water, Na 2 C0 3 + 10H 2 0. They belong to the 
 monoclinic system. Orthodiagonal : clinodiagonal : principal axis 
 = 07049 : 1 : 1-0452. Inclination of clinodiagonal = 57'40. Or- 
 dinary combination +P. ooP.[ooPoo] (fig. 126) ; ooP : oo P = 
 100 20'. Cleavage tolerably distinct parallel to oo P oo, less dis- 
 tinct parallel to [ oo P oo]. Specific gravity = 1'423 (Haidinger). 
 They effloresce in moderately dry air, crumbling to a white powder, 
 and giving off 5 at. water at 12-5C. and 9 at. at 38 (S chindler) ; 
 9 at. also in vacuo over oil of vitriol (B 1 ii c h e r). The 1 0-hy drated 
 salt occurs as a natural product called natron, together with the 
 mono-hydrate, at the soda-lakes of Egypt and Hungary, at Vesu- 
 vius, Etna, and in various parts of Asia, Africa, and America. 
 (Dana, ii. 455.) 
 
 a. Na'-'CO 3 + 15aq. is obtained in crystals, when a solution of the 
 neutral salt i* exposed to a temperature of 20 C., and the frozen water is afterwards 
 
CARBONATES. 795 
 
 allowed to liquefy ; and Na 2 CO* + 9aq. by repeatedly crystallising a solution which at 
 first contains a portion of acid carbonate. (Jacquelain, Compt. rend. xxx. 106.) 
 
 b. Na 2 C0 3 + 8 aq. crystallises in right rhombic prisms with four-sided summits, when 
 the 10-hydrated salt is melted and left to cool, or from a hot-saturated aqueous solu- 
 tion, apparently at a temperature lower than the crystallising point of the mono- 
 hydrated, and higher than that of the deca-hydrated salt. (Thomson, Annals oj 
 Philosophy, 26, 44.) 
 
 c. Na 2 C0 3 + 7aq. This hydrate crystallises in two forms, (a) rhombohedral ; (ft) in 
 trimetric crystals of the same form as Thomson's salt (which, according to Loewel, 
 contains, not 8 at. but 7 at. water). When a solution saturated at the boiling heat is 
 enclosed in a flask, which is corked immediately after the boiling has ceased, no crys- 
 tals are deposited from it for a long time on cooling down to between 25 and 18 C. ; 
 but on cooling below 8 it deposits chiefly the trimetric 7-hydrated salt. Between 16 
 and 10, it yields the rhombohedral salt (a), which redissolves between 21 and 22, 
 forms again at 19, and on cooling from 10 to 4 becomes opaque, and passes into b. 
 After cooling to a lower temperature and for a longer time, when the state of super- 
 saturation ceases, the whole is converted into a mass of crystals of the deca-hydrated 
 salt. (II. Loewel, Ann. Ch. Phys. [3] xxxiii. 334.) 
 
 d. Na 2 C0 3 + 6aq. crystallises from a solution of protosulphide of sodium exposed to 
 the air, and frequently also from a mixed solution of carbonate of potassium and 
 chloride of sodium. (Mitscherlich, Pogg. Ann. viii. 441.) 
 
 e. Na v C0 3 +5aq. is formed when the 10-hydrated salt effloresces at 12-5 C. 
 (Sch indler), also when the same salt is melted in its water of crystallisation, and after 
 the mono-hydrated salt has crystallised out between 70 and 80 C., the remaining 
 liquid is kept for some time at 34 ; it is also formed from the mono-hydrated salt by 
 exposure to the air (Berzelius). It was once accidentally obtained at the Buxweiler 
 soda works, in transparent rhombic octahedrons, which effloresced slightly in the air, 
 and when dissolved in water and evaporated at 30 C. yielded the same salt. (P er s oz, 
 Pogg. Ann. xxiii. 303.) 
 
 /. Na-CO 3 + aq. is formed from the deca-hydrate by efflorescence, and is found native 
 as thermonatrite, in the same localities as natron, and is indeed the more common salt 
 of the two. It forms rectangular tables of the trimetric system with bevelled edges. 
 
 The same hydrate separates from a solution of the neutral carbonate concentrated 
 by evaporation at the boiling heat, a circumstance which is made available in the soda 
 manufacture for the purification of the salt, the crystalline powder which separates 
 from the boiling solution being taken out and drained ; if left to cool in the solution, it 
 would redissolve. It does not undergo the aqueous fusion when heated, but gives off 
 its water and becomes opaque at 87 C. It absorbs water from moist air, and is con- 
 verted into the pentahydrate. In a warm atmosphere, it absorbs carbonic acid and 
 forms sesquicarbonate. 
 
 Solution of Carbonate of Sodium. According to Poggiale, 100 pts. of water dissolve 
 of the anhydrous salt, 7'08 pts. at C., 16-66 at 10, 25'93 at 20, 30-83 at 25, 35-90 
 'at 30, and 48*5 at 104-6, which is the boiling point of the saturated solution. Ac- 
 cording to Anthon, the 10-hydrated salt dissolves in 2 pts. of cold, and much less than 
 1 pt. of hot water. According to Loewel (loc. cit.~) 100 pts. of a saturated solution con- 
 tain of the 10-hydrated salt, 7 pts. at C., 12'1 pts. at 10, 16'2 pts. at 15, 217 pts. 
 at 20, 28'5 pts. at 25, 37'2 pts. at 30, 5T7 pts. at 38, and 45*5 pts. at 104. Hence 
 it appears that there is a maximum solubility at 38 C. 
 
 Solutions of carbonate of sodium are capable of assuming the state of supersatura- 
 tion, like those of the sulphate. A solution saturated at the boiling heat and imme- 
 diately enclosed in a sealed tube or a well corked flask, remains supersaturated at 
 common temperatures, and frequently even when cooled several degrees below C. 
 Keeping the air in contact with the liquid from agitation, as by covering the hot solu- 
 tion with a glass shade, is often sufficient to prevent crystallisation at ordinary tem- 
 peratures ; but access of air then causes immediate solidification, attended with rise of 
 temperature. The supersaturated solutions, as already observed, deposit the 7-hy- 
 drated salt in two different modifications, according to temperature (vid. sup.) 
 
 Monosodic Carbonate. Di-acid Carbonate of Sodium. Bicarbonate of Soda. 
 NaHCO'or Na 2 O.H 2 0.2C0 2 . This salt exists in solution in alkaline mineral 'waters'. 
 It is prepared : 1. By passing carbonic acid gas into a solution of the neutral carbo- 
 nate as long as it is absorbed. 2. By exposing the effloresced neutral carbonate 
 placed on trays in a wooden case to an atmosphere of carbonic acid. 3. By adding 
 commercial carbonate of ammonia (which is chiefly bicarbonate) to an equal weight of 
 chloride of sodium, dissolved in three times its weight of water, stirring the whole 
 well together, and leaving it to stand for several hours. Monosodic carbonate then 
 separates in crystalline grains, while chloride of ammonium remains in solution (p. 794) 
 NaCl + NHMI.CO 3 = NaHCO 3 + NH'Cl. 
 
796 CARBONATES. 
 
 The precipitate is separated from the liquid by pressure in a screw press, but it 
 always retains a portion of chloride of sodium. 
 
 Monosodic carbonate crystallises in oblique four-sided tables, and is sometimes ob- 
 tained by the first method in crystals of considerable size ; the second and third 
 methods yield it in the form of a crystalline powder. It has a slight alkaline taste and 
 reaction, and is permanent in dry air at ordinary temperatures. At a red heat, it gives 
 off water and carbonic acid, and is reduced to anhydrous neutral carbonate. 
 
 100 pts. of water dissolve of monosodic carbonate, 8 '95 pts. at C., 10-04 pts. 
 at 10, 11-15 pts. at 20, 12-24 pts. at 30, 14-45 pts. at 40, and 16-69 pts. at 70 
 (Poggiale). The solution gives off carbonic acid slowly at ordinary temperatures, 
 more quickly at 70 C., rapidly at the boiling heat, and is ultimately reduced to neu- 
 tral carbonate. It does not precipitate magnesium-salts in the cold, but at the boiling 
 heat carbonic acid escapes and a precipitate of carbonate of magnesium is formed ; this 
 character distinguishes it from the neutral carbonate. Acid carbonate of sodium is used 
 for the preparation of effervescing powders, and asaremedyin certain calculous disorders. 
 
 Tetrasodic Carbonate or Sesquicarbonate of Sodium. Na 4 H 2 C 3 9 + 
 2aq. = 2Na 2 O.H 2 0.3C0 2 + 2aq. This salt, which may be regarded as a compound 
 of the mono- and di-sodic carbonates (2NaHCO s + Na 2 C0 3 ), is found in Africa, in the 
 province of Sakenna, two days' journey from Fezzan, where it is called trona ; it 
 occurs at the foot of a mountain, forming a, crust, varying in thickness from an inch to 
 that of the back of a knife ; also as urao at the bottom of a lake in Maracaibo, South 
 America ; efflorescences of it occur also near the Sweetwater Eiver, Eocky mountains, 
 mixed with sulphate and chloride of sodium (Dana, ii. 454). It is produced artifi- 
 cially : 1. By mixing the mono- and di-sodic carbonates in the proportions above indi- 
 cated, melting them together, drying, and exposing the dried mass to the air of a 
 cellar for some weeks; it then absorbs water, becomes crystalline, and contains spaces 
 filled with shining crystals of tetrasodic carbonate. From a hot solution of mono- and 
 di-sodic carbonates, the two salts crystallise out separately on cooling (Hermann, 
 J. pr. Chem. xxvi. 312). 2. A solution of the monosodic salt, concentrated by boiling, 
 but not boiled long enough to reduce it to the disodic salt, deposits the tetrasodic salt 
 on cooling. 3. If 4 oz. of alcohol be poured on the top of a solution containing 100 
 grains of the disodic and 152 grains of the crystallised monosodic carbonate in 4 oz. of 
 water, fine clear needle-shaped crystals of the tetrasodic salt form, after some days, at 
 the surface of separation of the two liquids, while at the bottom of the solution, large 
 crystals of the disodic carbonate are found covered by a crust of the monosodic salt. 
 (Winckler, Gmeliris Handbook, iii. 83.) 
 
 The crystals of the native salt belong to the monoclinic system. Orthodiagonal : 
 clinodiagoual : principal axis = 0*3552 : 1 : 1-282. Inclination of clinodiagonal to prin- 
 cipal axis = 53" 50'. Observed combination oo P . oP . + P oo, prismatically elongated 
 in the direction of the orthodiagonal. oo P : oo P = 132 30'. Cleavage very perfect, 
 parallel to + P oo. They are colourless, transparent, or translucent, with vitreous 
 lustre. Specific gravity 2-112. Hardness 2'5 to 3. Structure foliated, radiating; 
 fracture conchoidal. The artificial crystals are small, and of the same form as the 
 native crystals. The salt has an alkaline taste and reaction, and is not efflorescent. 
 At a red heat, or when its aqueous solution is boiled for many hours, it is reduced to the 
 neutral carbonate. It is intermediate in solubility between the two preceding salts. 
 According to Poggiale, 100 pts. of water dissolve of it, 12*63 pts. at 0C., 18-30 pts. at 
 20; 38-95 pts. at 40; 29'68 pts. at 60; 35'80 pts. at 80; and 41-59 pts. at 100. The 
 solution is not rendered turbid by 1 pt. of sulphate of magnesium dissolved in 10 pts. 
 of water. Evaporated in vacuo over oil of vitriol, it yields a mass of crystals composed 
 of the mono- and di-sodic carbonates together. (H. Rose, Pogg. Ann. xxxii. 160.) 
 
 Carbonate of Sodium and Potassium. KNaCO 8 + 6aq. Separates from 
 a solution containing equivalent quantities of the component salts, in monoclinic crystals 
 exhibiting the faces ooP . ooP oo . [ ooP oo] . ooP2 . [ ooP2] . OP . + P . + P2 . + 
 P oo . 4- 2P oo [P oo] . + 2P oo. Inclination of faces ; ooP : ooP in the clinodiagonal 
 principal section = 108 34'; OP: ooPoo = 131 48'; OP : ooP = 122 46'; OP: 
 + Poo = 124 48'; OP: + 2Poo = 84 19' (Marignac, Compt. rend. xlv. 650). 
 Nearly the same angular values were observed by Senarmont. The crystals are per- 
 manent in the air. A salt containing K 2 Na 4 C 3 9 + 18aq. is mentioned by Margue- 
 ritte (Ann. Ch. Pharm. Ivi. 220) as crystallising from the mother-liquor of ferro- 
 cyanide of potassium, and from a concentrated solution of the simple salts ; but 
 Marignac was not able to obtain this compound, and is of opinion that the formula is 
 deduced from an incorrect analysis. 
 
 A mixture of the neutral carbonates of sodium and potassium in equivalent propor- 
 tions, fuses at a much lower temperature than either of the salts separately, doubt- 
 less in consequence of the formation of the double salt. Such a mixture is very useful 
 in the fusion of silicates, &c. 
 
CARBONATES. 797 
 
 Carbonate of Sodium and Calcium, CaNaC0 3 + 5 aq. Occurs abundantly, aa 
 Gay-Lussite, at Lagunilla near Merida, in Maracaibo, covering urao ; found also at 
 Sangerhausen in Thuringia. The crystals are monoclinic. Inclination of axes 
 = 78 27' ; <xP : cP = 68 50'. Cleavage perfect parallel to ooP : less perfect 
 parallel to OP. They are yellowish-white, translucent, double refracting, extremely 
 brittle, with conchoi'dal fracture, and exhibit a vitreous lustre on the broken surface. 
 Specific gravity = T92 1*99. Hardness = 23. The mineral decrepitates when 
 heated, and becomes opaque from loss of water. In the hydrated state it dissolves 
 sparingly in water, without decomposition ; but the anhydrous salt is resolved by water 
 into carbonate of sodium and carbonate of calcium. Crystals of Gay-Lussite, altered 
 to calcite, are sometimes called natrocalcite. (Dana, ii. 453). 
 
 The salt may be prepared by fusing the anhydrous carbonates of sodium and calcium 
 together in atomic proportions. 
 
 The double salts of carbonate of sodium with other metals, magnesium, cobalt, 
 zinc, &c., are described with the carbonates of those metals. 
 
 CARBONATE OF STRONTIUM. Sr 2 C0 3 . Occurs native as Strontianite, at 
 Strontian in Argyleshire, where it was first observed; also in Yorkshire, at the Giant's 
 Causeway, at Clausthal in the Harz, at Braunsdorf in Saxony, Leogang in Saltzburg, 
 and other localities. It forms crystals of the trimetric system, isomorphous with 
 arragonite and witherite. Katio of brachydiagonal to macrodiagonal to principal 
 axis = 0'6026 : 1 : 0*7237. The crystals are often prismatic from predominance of 
 the faces o>P . oo P oo and P oo. Cleavage tolerably perfect parallel to ooP, less per- 
 fect parallel to 2P oo. Specific gravity 3 -605 3713. Hardness 3 -5 to 4. Colour 
 white with various shades of grey, green, yellow, and brown. Streak white. Lustre 
 vitreous. Transparent or translucent. Fracture uneven. Brittle. Before the blow- 
 pipe it melts on the edges and swells up, emitting a brilliant light, and when strongly 
 heated in the reducing flame, imparts to it a reddish tinge. Strontianite occurs 
 altered to crelestine by the action of soluble sulphates. Baryto-strontianite, from 
 Stromness in Orkney, appears to be a mechanical mixture of the carbonates of stron- 
 tium and barium. 
 
 Carbonate of strontium obtained by precipitation is a white substance, smooth to 
 the touch and has but little cohesion. It dissolves in 18045 pts. of cold water, and in 
 56545 pts. of water containing ammonia or carbonate of ammonium (Fresenius); 
 in 300,000 pts. of water, whether cold or hot (Bine an, Compt. rend. xli. 509); in 
 833 pts. of water saturated with carbonic acid at 10 C. (Lassaigne), and in this 
 state it occurs in some mineral waters, whence it crystallises by evaporation in needle- 
 shaped crystals. When heated in close vessels, it does not give off carbonic anhydride 
 at any temperature short of that of a forge fire ; but in a stream of aqueous vapour or 
 moist air, the decomposition takes place at a lower temperature, with formation of 
 hydrate of strontium. It is not decomposed by solutions of alkaline sulphates at 
 any temperature. (H. Eos e, Pogg. Ann. xcv. 284). 
 
 CARBONATE or THORINUM. Alkaline carbonates, added to solutions of thori- 
 num-salts, throw down a basic salt, with evolution of carbonic acid. Moist hydrate of 
 thorinum absorbs carbonic acid from the air. The anhydrous earth is not soluble in 
 water containing carbonic acid. (Berzelius.) 
 
 CARBONATES or URANIUM. These salts do not appear to exist in the separate 
 state. Alkaline carbonates throw down from uranous chloride a precipitate of 
 uranous hydrate ; from uranous sulphate, a basic sulphate ; from uranic salts, precipi- 
 tates consisting of double carbonates. 
 
 Ammonio-uranic Carbonate, 2[(NH 4 )*O.C0 2 1 + TJ 4 S .C0 2 or Carbonate of TTranyl* 
 
 ( Nil 4 ) 4 ) 
 and Ammonium, /TT*Q\I [ CO 9 . On digesting the precipitate thrown down by ammonia 
 
 or carbonate of ammonia from a uranic salt in a solution of carbonate of ammonia 
 at 60 80 C., till the liquid is saturated, then filtering hot, and leaving the filtrate 
 to cool, this salt separates in small transparent yellow crystals. It decomposes 
 slowly in the air at common temperatures, more quickly when heated, ultimately leav- 
 ing a residue of brick-red urnnic oxide. It dissolves in 20 pts. water at 15 C., more 
 easily in water containing carbonate of ammonia. The solution, when boiled, gives 
 off carbonate of ammonia, and deposits the whole of the uranium as a yellow precipi- 
 tate, consisting, according to Arfvedson, of uranic oxide with small quantities of am- 
 monia and carbonic acid ; according to Peligot, of uranate of ammonium ; according 
 to Ebelmen, of uranic hydrate containing 2 per cent, ammonia, but no carbonic acid. 
 (Ebelmen, Ann. Ch. Phys. [3] v. 189; Delffs, Pogg. Ann. Iv. 229.) 
 
 Potassio-uranic Carbonate, K 4 (U 2 0) 2 C 3 9 . Obtained by dissolving in acid carbonate 
 of potassium the precipitate thrown down from uranic salts by the neutral carbonate, 
 
 * Uranyl, U 2 O, is a monatotnic radicle which may be supposed to exist in the uranic sails, e.g. uranic 
 nitrate, UO 8 .N*O 5 (UHNO 3 . (See URANIUM.) 
 
798 CARBONATES. 
 
 evaporating at a gentle heat, and reerystalliaing. It forms a bright-yellow crystalline 
 crust, which gives off carbonic anhydride at 300 C., and when heated to redness leaves 
 a red-brick mixture of uranate and carbonate of potassium. It dissolves in 13'5 pts. 
 of water at 15 C. without decomposition, but is partially decomposed by boiling water, 
 which throws down uranate of potassium. The same compound is deposited after a 
 while from a cold solution of the double carbonate, if very dilute and not containing excess 
 of carbonate of potassium. Caustic potash precipitates the whole of the uranium as 
 unwiate of potassium, even in the presence of a large excess of carbonate of potassium. 
 Acids, if not added in large excess, produce the same light yellow precipitate as is 
 produced by carbonate of potassium in uranic salts. The double salt is insoluble in 
 alcohol. (Ebelmen, loc. clt.) 
 
 Sodio-uranic Carbonate, Na 4 (U 2 0) 2 C 3 9 . Prepared like the preceding, which it re- 
 sembles. 
 
 Calcio-uranic Carbonate, Ca(U 2 0)CO 8 + 10 aq. Found native as Liebigitc, in 
 amorphous rounded masses, having a distinct cleavage in one direction, transparent, 
 of a beautiful apple-green colour, and vitreous lustre on the fractured surface. Hard- 
 ness 2 to 2*5. Gives off water when gently heated and turns blackish-grey ; does not 
 fuse at a red heat, but turns black, and acquires an orange-red colour on cooling. 
 Occurs, with Medjidite, near Adrianople, also at Johanngeorgenstadt, and in the 
 Joachimsthal. (J. L. Smith, Ann. Ch. Pharm. Ixvi. 253.) 
 
 A calcio-uranous carbonate, CaUCO 8 + f aq., occurring in siskin-green scaly aggrega- 
 tions on pitch-blende at the Elias mine near Joachimsthal, has been examined by Vogl 
 and Lindacker (Jahrb. k. k. geol. Eeichsantalt, iv. 1853, 221). A carbonate of ura- 
 nium, copper, and calcium, called Voglitc, which may be regarded as an orthocarbonate 
 (U 4 Cu 6 Ca'"H 8 )C 5 0'- + 10 aq., occurring in the same locality in aggregations of green 
 dichroic, crystalline, pearly scales, has also been examined by Liudacker (loc. cit.) 
 
 CARBONATE OF YTTRIUM, Y'-'CO 3 (containing also erbium and terbium). Precipi- 
 tated from yttrium-salts by carbonate of sodium, with 13 at. water in the cold, with 
 2 at. at the boiling heat. It is not easily decomposed by heat ; dissolves sparingly 
 in water containing carbonic acid; decomposes ammoniacal salts and dissolves in the 
 liquid. Its solution in carbonate of ammonia deposits, after a time, if concentrated, a 
 white crystalline double salt, which does not redissolve in carbonate of ammonia. 
 Carbonate of yttrium dissolves also, though less easily, in the carbonates of potassium 
 and sodium. (Berzelius.) 
 
 CARBONATES OF ZINC. The neutral carbonate, or metacarbonate, Zn 2 C0 3 , occurs 
 native as calamine (p. 713). It is doubtful whether this anhydrous salt can be ob- 
 tained by precipitation. According to Schindler (G-melin's Handbook, v. 16) it is 
 produced by precipitating a solution of 1 at. sulphate of zinc in 10 pts. water with 
 1 at. diacid carbonate of potassium or sodium ; but, according to Berzelius, the precipi- 
 tate thus formed is Zn 2 C0 3 .3ZnHO. 
 
 Hydrocarbonates. Zinc-bloom, which occurs in nature as an earthy incrustation 
 and in reniform masses, has, according to Berzelius, the composition 5Zn 2 O.C0 2 + 3aq., 
 or Zn 2 C0 3 .Zn 2 0.6ZnHO ; according to the analyses of Smithson and Bonsdorff, it is 
 3Zn 2 O.C0 2 + 3aq., or Zn 2 C0 3 .4ZuHO + aq. It is dull and opaque, with white, greyish, 
 or yellowish colour, and makes a shining streak. Specific gravity = 3'58 to 3*6. Hard- 
 ness = 2 to 2'5 (Grm. vi. 15). Aurichalcite, or green calamine (p. 476), found in the 
 Altai, and at Matlock in Derbyshire, may be regarded as Zn 2 C0 3 .3ZnHO, in which 
 the zinc is partly replaced by copper. jBuratite (p. 686) is a hydrocarbonate of zinc 
 containing copper and calcium, perhaps a mixture. 
 
 The precipitates formed by alkaline carbonates in solutions of zinc-salts, all appear 
 to contain water, their constitution varying with the strength and temperature of the 
 solutions, and with the nature and proportion of the precipitant. The results obtained 
 in individual cases are variously stated by different authors ; those obtained by H. Eos e 
 (Pogg. Ann. Ixxxv. 107; Ann. Ch. Pharm. Ixxxiv. 210) are as follows: 
 
 a. With 1 at. Sulphate of Zinc and 1 at. Neutral Carbonate of Sodium. When the 
 solutions are cold and concentrated, the precipitate consists mainly of Zn C0 3 .3ZnHO 
 f aq., it remains unaltered at 60 C., but, after drying at 100, is composed of 
 2Zn 2 C0 3 .7ZnlIO + |aq. Very dilute cold solutions and concentrated boiling solutions 
 yield a precipitate consisting mainly of Zn 2 C0 3 .ZnHO, or Zn'HCO 4 , combined with 
 variable quantities of water. 
 
 b. With excess of 'Neutral Carbonate of Sodium. The precipitate from cold solutions 
 contained, when dried at 100 C., 5Zn 2 C0 3 .18ZnHO ; from moderately warm solutions 
 3Zn 2 C0 3 .l()ZnHO (at 100), but if very large quantities of liquid were used, it con- 
 sisted of Zn 2 C0 3 .2ZnIIO. 
 
 c. With 1 at. Sulphate of Zinc and 1 at. Acid Carbonate of Sodium. (NaHCO 3 ). 
 The precipitates contain more carbonic acid than the preceding. When they are dried 
 
CARBONIC ETHERS. 799 
 
 in vacuo, a large quantity of carbonic acid escapes, and there remains the compound 
 Zn 2 C0 3 .3ZnHO + aq. 
 
 d. With excess of Acid Carbonate of Sodium. From cold solutions a precipitate was 
 several times formed containing 2Zn 2 CO s .5ZnHO + ^aq. (at 100). A precipitation 
 on the large scale, with rather warm solutions, yielded Zn 2 C0 3 .ZnHO. The precipi- 
 tate obtained with cold solutions, after standing for some time, had, when air-dried, 
 but not washed, the composition 3(2Zn'-'C0 3 .ZnHO. + faq. ; after drying at 100, it 
 became 2Zn 2 C0 3 .ZnHO. 
 
 e. With exass of Acid Carbonate of Potassium. The precipitate not washed, but. 
 dried between filtering paper, had the composition 2Zn'-'CO 3 + 2H 2 O. After washing with 
 cold water and drying in the air, it became 4Zn 2 C0 3 + 5aq. ; at 100 it was reduced 
 to 4Zn' 2 C0 3 + aq. ; and at 200 to 6Zn 2 CO s + aq. 
 
 According to Schindler, basic salts having the composition 8Zn 2 O.C0 2 + 2aq., or 
 Zn 2 C0 3 .7Zn 2 0.2H 2 and 4Zn 2 O.C0 2 .2H 2 0, or Zn-'C0 3 .3Zn 2 0.2H 2 0, are obtained by 
 precipitating the corresponding sulphates of zinc with carbonate of sodium. Accord- 
 ing to Boussingault, ordinary sulphate of zinc precipitated with sesquicarbonate of 
 sodium at ordinary temperatures, yields the salt 2Zn 2 O.C0 2 + 2aq., or Zn 4 C0 4 -t- 2aq. 
 According to Schindler, hot solutions of these salts yield a precipitate of the same 
 composition as zinc-bloom. (Grin. v. 15.) 
 
 All the hydrocarbonates of zinc give off their water and carbonic anhydride at 
 200 C., and are reduced to zinc-oxide, Zn 2 0. The native carbonate remains unaltered 
 at 200, but slowly gives off carbonic anhydride at 300. (H. Kose.) 
 
 Ammonio- carbonate of Zinc, NH 3 .Zn'-'C0 8 , or Carbonate of Zinc am 
 
 Zn NH 3 Zn [ 2 * Deposited *** crystals from a solution of precipitated carbonate of zine 
 in a strong solution of carbonate of ammonium. (Favre, Traite de Chimie par Pelouze 
 ct Fremy, 2 me ed. iii. 47.) 
 
 Carbonate of Zinc and Potassium. (Zn 12 K 8 H 2 )C n 33 + 7aq. Deposited in crystals 
 from a solution of chloride of zinc mixed with sesquicarbonate of potassium. (De ville, 
 Ann. Ch. Phys. [3] xxxiii. 75.) 
 
 Carbonate" of Zinc and Sodium. (Zn^lSTa^C^O 33 + 8aq. Small shining crystals, 
 apparently tetrahedrons and octahedrons, obtained in like manner. (De ville.) 
 
 CARBONATE OF ZIRCONIUM. Solutions of zirconium-salts, treated with excess 
 of alkaline carbonate, yield a precipitate soluble in acid carbonates of alkali-metal, and 
 containing, according to Hermann, 76'6 per cent, zirconia and 20'39 per cent, water, 
 agreeing with the formula 2Zr 4 3 .C0 2 + 6aq. According to Klaproth, however, it con- 
 tains 51 '5 per cent., and, according to Vauquelin, 55*5 per cent, zirconia. 
 
 CARBONIC ACID and ANHYDRIDE. See CARBON, OXIDES or (p. 770). 
 
 CARBONIC ETHERS. Carbonates of Alcohol-radicles. These compounds are 
 metacarbonates, M 2 C0 3 , in which one or both atoms of base are alcohol-radicles. 
 Those which contain 2 at. of alcohol-radicle, the neutral carbonic ethers, are obtained : 
 
 1. By the action of carbonate of silver on the iodides of the alcohol-radicles. 2. By 
 
 the action of potassium or sodium on the corresponding oxalates. This reaction is 
 attended with evolution of carbonic oxide, and probably takes place in the manner 
 represented by the following equation : 
 
 2(C 2 H 5 ) 2 C 2 0* + K 2 = (C 2 H 5 ) 2 C0 3 + 2C 2 H 5 KO + SCO. 
 
 Oxalate of ethyl. Carbonate of Ethyiate of 
 
 ethyl. potassium. 
 
 3. By the action of water on the chlorocarbonates of the alcohol-radicles (produced 
 by passing oxychloride of carbon into the alcohols), and by the dry distillation of 
 these same products. In presence of water, the action is such as is represented by 
 the equation, 
 
 2 (rnr4n) + H2 = (C 5 H) 2 CO' + CO 2 + 2HCL 
 
 VC 2 EP}Ciy Carbonate of 
 
 Chlorocarbo- amvl 
 
 nate of amyl. 
 
 The decomposition of the chlorocarbonates by dry distillation is more complicated, 
 a considerable quantity of charred matter remaining behind ; but the principal reaction 
 is doubtless the splitting up of 2 at. of the chlorocarbonate into a carbonic ether and 
 oxychloride of carbon, e. g. : 
 
 2(CC10 2 .C 5 H n ) = (C 5 H U ) 2 CO S + COC1 2 . 
 
 The neutral carbonic ethers are ethereal oily liquids, insoluble in water, soluble in 
 alcohol and ether. They are decomposed by alcoholic potash, yielding carbonate of 
 potassium and the corresponding alcohols. Two volumes of the vapour of each of these 
 ethers contain two volumes of alcohol-radicle, a fact which tends to establish the dibas- 
 icity of carbonic acid. (See ACIDS, p. 4G.) 
 
800 CARBONIC ETHERS. 
 
 The acid carbonic ethers (carbonates of alcohol-radicles and hydrogen) are not 
 known, but some of their salts have been prepared. 
 
 CABBONATE OF ALLYL. C 7 H'0 3 = (C 3 H 5 ) S C0 3 . Obtained by the action of 
 iodide of allyl on carbonate of silver (Zeise, Ann. Ch. Pharm. xcvi. 361), or of potas- 
 sium or sodium on oxalate of allyl (Cahours and Hofmann, Phil. Trans. 1857, p. 
 655). It is an ethereal liquid lighter than water. The alcoholic solution treated with 
 hydrate of barium, yields carbonate of barium and allyl-alcohol. 
 
 CARBONATE OF AMYL. C'-H-'-'O 8 = (C 5 H n ) 2 CO J . Prepared: 1. By saturating 
 amylic alcohol with oxychloride of carbon, decomposing the product with water, treat- 
 ing it with oxide of lead to remove chlorine, drying over chloride of calcium, and rec- 
 tifying (Medlock, Chem. Soc. Qu. J. i. 368). 2. By decomposing oxalate of amyl 
 with potassium or sodium. The action begins immediately, but heat is required to 
 complete it. By distillation, a yellow liquid is obtained, which begins to boil at 130C., 
 yielding amylic alcohol ; afterwards carbonate of amyl passes over at 225, the quantity 
 amounting to about three-fourths of the original distillate. The residue contains a 
 strong-smelling viscid matter. (Bruce, Chem. Soc. Qu. J. v. 132.) 
 
 Carbonate of amyl is a colourless liquid, having an agreeable odour, and specific 
 gravity = 0'9144; it boils at 224 225 C. 
 
 CABBONATE OF ETHYL. Carbonic Ether. C 5 IT 3 = (C H 5 ) 2 C0 3 . This ether 
 is prepared : 1. By the action of potassium or sodium on oxalate of ethyl, the materials 
 being nested in a retort to 130 C., and fresh potassium or sodium added, as long as car- 
 bonic oxide continues to escape. On cooling the residue and treating it with water, 
 carbonate of ethyl rises to the surface : it is dried with chloride of calcium, and rectified 
 over a small quantity of sodium, then heated alone till the boiling point becomes 
 stationary, the portion which afterwards passes over being collected apart (Ettling, 
 'Ann. Ch. Pharm. xix. 17). 2. By distilling a mixture of ethyl-carbonate and ethyl- 
 sulphate of potassium. (Chancel, Compt. rend. xxxi. 521.) 
 
 C 2 H S .K.CO S + C 2 H 5 .K.SO< = K 2 SO* + (C 2 H 5 ) 2 C0 3 . 
 
 Carbonate of ethyl is a colourless limpid oil, having a sweet ethereal odour, and 
 burning taste. Specific gravity = 0-975 at 19 C. Boils at 125, and volatilises without 
 decomposition. Vapour- density = 4*243 (Ettling); 4'09 (Cahours); by calculation 
 
 for a condensation to 2 vol. it is - - - x 0'0693 =4-089. It is inflammable, 
 
 and burns with a blue flame. It is insoluble in water, but dissolves easily in alcohol 
 and ether. With alcoholic potash, it yields alcohol and carbonate of potassium. Heated 
 with sodium, it gives off carbonic oxide, and forms ethylate of sodium, together with 
 carbonate (?) (Lowig, Pogg. Ann. 1. 122). The reaction is perhaps : C 5 H 10 S + Na = 
 2C 2 H 5 NaO + CO (Gm.ix. 393). Chlorine decomposes carbonate of ethyl, abstracting 
 hydrogen, and forming the two following substitution-products : 
 
 Tetrachlorocarbonic Ether, C 5 H 6 CP0 3 , commonly called Eichlorocarbonic ether. 
 Obtained by passing chlorine through carbonate of ethyl in diffused daylight, heat- 
 ing the liquid to 70 80 C. in the latter part of the process, and expelling the excess 
 of chlorine by a stream of carbonic anhydride. It is a colourless liquid having a sac- 
 charine odour, much heavier than water, and insoluble therein ; soluble in alcohol. It 
 is decomposed by dry distillation. (Cahours, Ann. Ch. Phys. [3] ix. 201.) 
 
 Perchlorocarbonic ether, C 5 C1 I0 3 . (Cahours, loc. cit. ; Malaguti, Ann. Ch. 
 Phys. [3] xvi. 30.) Produced by the continued action of chlorine on the preceding 
 compound in direct sunshine. The resulting crystalline mass must be purified by 
 pressing it between folds of bibulous paper, washing it rapidly with small quantities of 
 ether, again pressing, and leaving it for some days in a dry vacuum. It cannot be 
 purified by crystallisation from alcohol or ether. 
 
 It is a white mass, composed of small needles, and having a faint odour; melts 
 between 86 and 88 C., and solidifies between 65 and 63. At a higher temperature 
 it partly distils unaltered, and is partly resolved into carbonic anhydride, chloride of 
 trichloracetyl, and trichloride of carbon : 
 
 C 5 CP0 3 = CO 2 + C 2 CPO.C1 + C 2 C1 6 . 
 
 When dissolved in alcohol, it changes to an oil which is a mixture of carbonate and 
 trichloracetate of ethyl, a large quantity of hydrochloric acid being produced at the 
 same time : 
 
 C 5 C1 10 8 + 4C 2 H 6 = (C 2 H 5 ) 2 C0 3 + 2(C 2 H 5 .C 2 C1 3 2 ) + 4HC1. 
 
 Heated with potash-ley, it yields formate, chloride and acid carbonate of potassium, 
 together with hydrochloric acid : 
 
 C 5 C1'0 3 + 10KHO = 2CHK0 2 + 5KC1 + 5HC1 + 3KHC0 3 . 
 With gaseous ammonia, it forms sal-ammoniac, chlocarbethamide (trichloracetamide, 
 
CARBONITROTOLUYLIC ACID. 80i 
 
 according to Grerhardt, TraitS, i. 16*6), and an unknown substance, which crystallises 
 in long needles (Malaguti). When thrown into aqueous ammonia, it makes a hissing 
 noise, like red-hot iron in water, and forms trichloracetamide, together with carbonate, 
 formate, and chloride of ammonium, and probably also other ammoniacal salts. (Mala- 
 guti.) 
 
 CARBONATE OF ETHYL AND POTASSIUM. Ethyl-carbonate or Carbovinate of 
 of Potassium,, C*H 5 K0 3 = C 2 H 5 .K.C0 8 . (Dumas and Peligot, Ann. Ch. Phys. [2] 
 Ixxiv. 6.) Obtained by passing carbonic anhydride into a solution of perfectly dry 
 hydrate of potassium in absolute alcohol, the liquid being carefully kept cool, which 
 is best effected by introducing from time to time small portions of anhydrous ether. 
 A crystalline deposit then forms, consisting of ethyl-carbonate of potassium, together 
 with neutral and acid carbonate. The ethyl-carbonate is formed as represented by 
 the equation : 
 
 C 2 H 6 + KHO + CO 2 = C 2 H 5 .KCO S + H 2 ; 
 
 the acid carbonate results from the action of the water thus formed on a portion of the 
 ethyl-carbonate, and the neutral carbonate from that of the excess of potash on the 
 acid carbonate. To separate the ethyl-carbonate, the mass is treated with an equal 
 volume of ether, which dissolves the excess of free potash, and leaves the two other 
 salts undissolved : the ethyl-carbonate is then dissolved out by alcohol, precipitated by 
 ether, and rapidly dried. It might doubtless be more easily prepared from anhydrous 
 ethylate of potassium, C 2 H 5 KO. 
 
 Ethyl-carbonate of potassium is a white nacreous salt, which burns with flame on 
 platinum-foil, leaving a carbonaceous residue, and yields by distillation an inflam- 
 mable gas, a small quantity of ethereal liquid, and a residue of carbonate mixed with 
 charcoal Water transforms it into alcohol and acid carbonate of potassium : 
 C 2 H 5 .K.C0 3 + H 2 = C 2 H 5 .H.O + KHCO 3 . 
 
 Ethyl-carbonic acid, C 2 H 5 .H.C0 3 , has not yet been obtained ; neither has Carbonate 
 of methyl, (CH 3 ) 2 C0 3 J nor Methyl-carbonic acid, CH 3 .H.C0 3 . 
 
 CARBONATE OF METHYL AND BARIUM. Methyl-carbonate of Barium. 
 CH 3 .Ba.C0 3 (Dumas and Peligot, loc. cit.) A solution of anhydrous baryta in an- 
 hydrous methylic alcohol, subjected to the action of carbonic anhydride, yields a white 
 precipitate, which after washing with methylic alcohol, consists entirely of methyl- 
 carbonate of barium : 
 
 CIP.H.O + Ba 2 + CO 2 = CH 3 .Ba.C0 3 + BallO. 
 
 The salt is insoluble in methylic or ethylic alcohol, but dissolves easily in cold water. 
 The solution soon however becomes turbid, depositing a considerable quantity of car- 
 bonate of barium and giving off carbonic anhydride. The action is greatly assisted 
 by a gentle heat, and at the boiling-point it is instantaneous. 
 
 CARBONATE OF METHYL AND ETHYL. C 4 1I 8 3 = CH 3 .C 2 H 5 .C0 3 (Chancel, 
 Compt. rend. xxxi. 521). Obtained by distilling a mixture of methyl-carbonate and 
 ethyl-sulphate of potassium : 
 
 CH 3 .K.C0 3 + C 2 H 5 .K.S0 4 = K 8 S0 4 + CH 3 .C-H 5 .CO S . 
 
 CARBONATE OF PHENYL AND HYDROGEN. C 6 H 5 .H.C0 3 . Salicylic acid (q. v.) 
 may be regarded as constituted in this manner. When subjected to dry distillation, 
 it splits up into carbonic anhydride and hydrate of phenyl. 
 
 CARBONATE OF TETRYL. Carbonate of Butyl. C 9 H 18 3 = (C 4 H 9 ) 2 .C0 3 . Pro- 
 duced: 1. By the action of iodide of tetryl on carbonate of silver, the materials 
 (12 grammes of each) being enclosed together in a sealed flask, and heated for two days 
 in the water-bath, distilling the product, collecting apart that which passes over above 
 180 C., and rectifying (Ph. de Clermont, Ann. Ch. Phys. [3] xliv. 336). 2. By the 
 action of chloride of cyanogen, either gaseous or liquid, on tetrylic alcohol, in presence 
 of water. (Humann, ibid. xliv. 340) : 
 
 2(C 4 H 9 .H.O) + CNC1 + H 2 = (C'H 9 ) 2 C0 3 + NH'CL 
 
 It is a colourless limpid liquid, lighter than water, and having an agreeable odour like 
 that of carbonate of ethyl. It boils at 190 C. Aqueous ammonia converts it into 
 tetrylic alcohol and carbonate of tetryl. 
 
 CARBOKTITROTOHnrilC ACID, also called Nitrodracylic acid. An acid 
 crystallising in white slender needles, obtained by treating toluene with excess of strong 
 nitric acid. Grlenard and Boudault (Compt. rend. xix. 505), who discovered it, 
 assigned to it the formula C 8 H fi N0 4 ; it is more probably isomeric with nitrotoluylic 
 acid, C 8 H 7 N0 4 ; or perhaps, as suggested by List (Gin. xiii. 24), the product was 
 merely nitrobenzoic acid containing nitrostyrol. 
 
 VOL. I. 3 F 
 
802 CAKBONYL CARBOVINIC ACID. 
 
 CO. The diatomic radicle of the carbonates, carbamates. carba- 
 
 mides, &c. 
 
 CARBOPVRROX.XC ACID. C 5 H 5 N0 2 = NH2 (C 5 H 2 0)"| Q (Schwanert, 
 
 Ann. Ch. Pharm. cxiv. 63.) An amic acid, obtained by heating Malaguti's pyromuca- 
 mide, C 5 H 6 N 2 (q.v.), which Schwanert regards as carbopyrrolamide, N 2 .H 4 .(C 5 H 2 0)", 
 with baryta- water in sealed tubes. Ammonia is then formed, together with carbopyrro- 
 late of barium, C 5 H 4 BaN0 2 , which crystallises in nacreous laminse, and is not decom- 
 posed by heating with potash-ley. The concentrated aqueous solution treated with 
 hydrochloric acid, deposits carbopyrrolic acid as a white crystalline precipitate. The 
 It ad-salt, C 5 H 4 PbN0 2 . forms sparingly soluble nacreous laminae. 
 
 When the aqueous solution of carbopyrrolic acid is heated to 60 C. or above, pyrrol, 
 C 4 H 5 N, separates from it as a brown flocculent substance. 
 
 CARBOSTYRXXt. C 9 H 7 NO = N(C 8 H 7 )(CO)". Produced by the action of sul 
 phide of ammonium on nitrocinnamic acid. Probably an acid, C 8 H 9 N0 2 , is first pro 
 duced and afterwards converted into carbostyril by loss of 1 at. water, thus : 
 
 C 8 H 9 (N0 2 )0 2 + 2H 2 S = C 8 H 9 N0 2 + 2H 2 + S a 
 Nitrocinnamic 
 acid. 
 
 and C 8 H 9 N0 2 -H 2 = C 8 H T NO. 
 Carbostyril. 
 
 The liquid is supersaturated with hydrochloric acid, filtered, and evaporated. It then 
 deposits crystals of carbostyril, coloured brown by a resin, which may be removed by 
 recrystallising the product several times from boiling water. 
 
 Carbostyril forms beautiful colourless silky needles, moderately soluble in boiling 
 water, easily in alcohol and ether ; melts when heated, and at a higher temperature 
 sublimes in shining needles ; dissolves in hydrochloric acid, also in boiling potash, 
 not in ammonia or in sulphuric acid. Heated with solid potash, it yields an oil which 
 appears to be a peculiar alkaloid (C 8 IPN ?) Boiled with oxide of silver, it forms a 
 compound insoluble in boiling water, from which it is separated by acids in its original 
 state. (Chiozza, Compt. rend, xxxiv. 598.) 
 
 CARBOTHIACETONTWE. C 10 H 18 N 2 S 2 . The sulphydrate of this base is de- 
 posited in yellow crystals on mixing acetone with ammonia and sulphide of carbon : 
 
 3C 3 H 6 + CS 2 + 2NH 3 = C 10 H 18 N 2 S 2 -i- 3H 2 0. 
 (Stadeler, Pharm. Centr. 1853, p. 433; see also ACETONE, p. 28.) 
 
 CARBOTHXAX.DXNE:. C 5 H'N 2 S 2 . A colourless crystalline body, produced by 
 adding sulphide of carbon to an alcoholic solution of aldehyde-ammonia. It is inso- 
 luble in cold water and in ether, sparingly soluble in cold alcohol, easily in boiling 
 alcohol. Dissolves in hydrochloric acid, and is reprecipitated by ammonia. Boiled 
 with excess of hydrochloric acid, it is resolved into sulphide of carbon, sal-ammoniac, 
 and aldehyde. On adding oxalic acid and then ether to the alcoholic solution of car- 
 bothialdine, crystals of oxalate of ammonium are formed. The alcoholic solution 
 forms, with nitrate of silver, a greenish-black precipitate, which gradually changes into 
 sulphide of silver ; with mercuric chloride it forms a thick white curdy precipitate, and 
 with copper- salts a green precipitate. (Redtenbacher and Lie big, Ann. Ch. 
 Pharm. Ixv. 43.) 
 
 (C 
 C ARBOTRI AIVTINE. N 3 -- 5 . Guanidine, a base obtained by the action of 
 
 oxidising agents on guanine, may be viewed as a triple molecule of ammonia (N 3 H 9 ), 
 in which 4 at. H are replaced by the tetratomic radicle carbon. Several substitution 
 derivatives of carbotriamine are also known, viz. : 
 
 Carbomethyltriamine. N 3 .C.(CH 8 )H 4 . This constitution may be ascribed to me- 
 thyluramine, a base resulting from the action of oxidising agents on creatine. 
 
 Carbotriethyltriamine. N 3 .C.(C 2 H 5 ) 3 H 2 . Produced by heating cyanurate of ethyl 
 with ethylate of sodium. (Hofmann, Proc. Roy. Soc. xi. 282.) 
 
 Carbodiphenyltriamine. N 3 .C.(C 6 H 5 ) 2 .H 3 . This is the composition of melaniline. 
 
 Carbotriphenyltriamine. N 3 .C.(C 6 H 5 ) 3 .H 2 . This base is produced by the action of 
 tetraehloride of carbon on phenylamine (p. 765). 
 
 All these bases may likewise be regarded as diamines containing 1 at. cyanogen in 
 place of 1 at. hydrogen ; thus, carbotriamine ~ cyan-diamine = N 2 (CN).H 5 . (See 
 ETHYL-, METHYL-, and PHENYL-DIAMINES and TRIAHINES.) 
 
 CARBOVXKTZC ACID. Syn. with CARBONATE or ETHYL and HYDROGEN. (See 
 CARBONIC ETHKRS, p. 801). 
 
CARBOVINOMETHYLIDE - CAREX. 803 
 
 CARBOVIK'OIVIETK'ZIiIDE. CARBONATE OF ETHYL and METHYL (p. 801). 
 
 CARXSITXTCXiE. A gein highly prized by the ancients, probably the almandin 
 or noble garnet. 
 
 CARBUREXC ACID. Syn. with ALLOPHANIC ACID. 
 
 SUXPHATE OP. C 2 H 4 S-'0 6 . Syn. with ETHJONIC ANHYDRIDE. 
 
 A3MCARA. The dried herb of this plant contains an azotised 
 and sulphuretted organic acid, either identical with or very similar to the myronic acid 
 of black mustard seed, in combination with an organic (probably basic) compound. 
 Moreover this acid, either free or in combination with bases, develops, under the in- 
 fluence of myrosyn, but not under that of the emulsion of bitter almonds, an acrid 
 volatile oil, very much like oil of horse-radish or scurvy grass. The decided bitterness 
 and lower degree of pungency of the fresh herb appear to be due to the absence of 
 myrosyn or of some analogous compound capable of developing the pungent oiL 
 (Winckler, Jahrb. pr. Pharm. xviii. 89.) 
 
 CARDAMOM Oils. An essential oil extracted by distillation from the seeds of 
 several kinds of cardamom, especially Alpmia eardamomum and Amomum repens. It is 
 pale, aromatic, and has a burning taste. Specific gravity, 0-945. Soluble in ether, 
 alcohol, and oils, also in acetic acid and caustic potash. It detonates with iodine, and 
 is set on fire by strong nitric acid. The oil amounts to 4*9 per cent, of the seed-kernela 
 of amomum repens. 
 
 Crystals deposited from old cardamom oil were found by Dumas and Peligot 
 (Ann. Ch. Phys. [2] Ivii. 334) to have the formula of a hydrate of camphene, 
 C 10 H 16 .3H 2 0. 
 
 Cardamom also contains a fixed non-drying oil, which has a rancid bitter taste, and 
 saponifies by boiling with potash. 
 
 CARDOXi. An oily liquid contained, together with anacardic acid (p. 209), in the 
 pericarp of the cashew-nut (Anacardium or Cassuvium occidentale). To obtain, it the 
 pericarp is exhausted with ether, the ether distilled off, the residue washed with water 
 to remove tannin, then dissolved in 15 to 20 pts. of alcohol, and digested with recently 
 precipitated hydrate of lead, which takes up the anacardic acid, while the cardol re- 
 mains in solution. The greater part of the alcohol is removed from the filtered liquid 
 by distillation, water added to the remaining liquid till it becomes turbid, and after- 
 wards acetate and subacetate of lead till it is decolorised. Lastly, the lead is precipi- 
 tated by sulphuric acid. 
 
 Cardol is a yellow oily liquid, insoluble in water, very soluble in alcohol and ether ; 
 the solutions are neutral to litmus. It is not volatile, but decomposes when heated. 
 It blisters the skin strongly. According to Stadeler, it contains 60 per cent, carbon 
 and 8'8 or 8'9 hydrogen, whence he deduces the formula C^^O*; it should perhaps 
 be C^H^O 2 . 
 
 Cardol precipitates basic, but not neutral acetate of lead. Strong sulphuric acid 
 dissolves it with red colour. Nitric acid appears to form with it under certain cir- 
 cumstances, the same products as with anacardic acid. Strong potash-ley colours it 
 yellow, and ultimately dissolves it ; and the solution, in contact with the air, acquires 
 a deep red colour, and then forms red or violet precipitates with most metallic salts. 
 (Stadeler, Ann. Ch. Pharm. Ixiii. 137.) 
 
 CAREX. The ashes of Carex remota and C. acuta have been examined by E. 
 Witting. (J. pr. Chem. Ixix. 149.) 
 
 The fresh plants contained in 100 pts. : 
 
 Carex remota .... 5275 45*18 2-07 
 
 acuta .... 69-60 29'28 1-12 
 
 The ash contained : 
 
 C. remota . 
 C. acuta 
 
 C. remota 
 C. acuta 
 
 The quantities of soluble and insoluble constituents of the ash were as follows 
 
 i Soluble in Soluble in T , ,, 
 
 water. nitric acid. Insoluble. 
 
 4915 29-45 21'40 - 
 
 67'56 31-59 10-85 
 
 3 F 2 
 
 KC1 
 
 NaCl 
 
 K 2 
 
 Na 2 
 
 Ca 2 
 
 Mg 2 
 
 2-81 
 
 10-23 
 
 23-52 
 
 0-72 
 
 7-86 
 
 9-22 
 
 4-90 
 
 7-28 
 
 37-94 
 
 0-35 
 
 7-90 
 
 7-36 
 
 Fe 4 3 
 
 Mn 2 
 
 P 2 5 
 
 SO 3 
 
 CO 2 
 
 SiO 2 
 
 2-23 
 
 1-45 
 
 4-95 
 
 1-93 
 
 4-75 
 
 30-33 
 
 1-39 
 
 2-02 
 
 7-66 
 
 1-36 
 
 4-86 
 
 16-98 
 
804 CARICA CARMINE. 
 
 CARZCA PAP ATA. Papaw Tree. Every part of the papaw tree, except the 
 ripe fruit, affords a milky juice, which is used in the Mauritius as an effectual remedy 
 for the tape-worm. In Europe, however, whither it has been sent in the concrete 
 state, it has not answered. The milky juice is said to make meat washed in it very 
 tender, and the leaves and fruit are said to have the same effect upon the flesh of old 
 hogs and poultry which are fed with them ; the flesh, however, soon becomes putrid. 
 The juice yields a substance resembling the flesh or fibre of animals. U. 
 
 CARIES. See BONE (p. 623). 
 
 CARIKTTHIIO 1 . A sub-species of augite. Colour black. Occurs massive and disse- 
 minated. Internally splendent. Eesino-vitreous. Distinct cleavage of 124 34'. Fracture 
 conchoidal. Greenish-black variety : translucent on the edges, velvet-black, opaque. 
 Occurs on the Saualp in Carinthia, in a bed of primitive rock, associated with quartz, 
 kyanite, garnet, and zoisite. (Jameson's Mineralogy.) U. 
 
 Dana (ii. 172) enumerates it as a variety of hornblende. 
 
 C ARMZDZNE. An organic base produced by passing lutidine over red-hot lime. 
 Its composition has not been ascertained. It produces a fine red colour with pine- 
 wood and hydrochloric acid, and pale green with bleaching powder ; hence it is pro- 
 bably a mixture of pyrrhol and vertidine. (Gr. Williams, Chem. Soc. Qu. J. 
 vii. 97.) 
 
 CARMITJ APHTHA. C 18 H 8 3 (?) A red colouring matter obtained by heating 
 naphthalene with a solution of acid chromate of potassium, and adding sulphuric or 
 hydrochloric acid. It is dissolved by alkalis and precipitated in its original state by 
 acids. (Laurent, Eev. scieut. xiv. 560.) 
 
 CARMZNDZN*. A product which Laurent obtained by the action of ammonia on 
 dibromisatiu. (See ISATIN.) 
 
 CARMZXrE. CARIKZNZC ACXX>. (Pelletier and Caventou, Ann. Ch. 
 Phys. [2] viii. 250, H. 194 ; Warren de la Eue, Ann. Ch. Pharm. bdv. 1, 23 ; Gerh. 
 iii. 750.) The colouring matter of cochineal (Coccus cacti). To separate it, cochineal 
 is exhausted with boiling water ; the extract is precipitated by subacetate of lead 
 slightly acidulated, care being taken not to add the lead-solution in excess ; the 
 precipitate is washed with distilled water till the wash- water no longer gives a preci- 
 pitate with a solution of mercuric chloride, then decomposed by sulphuretted hydrogen ; 
 the filtrate is evaporated to a syrupy consistence and dried over the water-bath ; and 
 the dark purple product thus obtained is treated with alcohol, which extracts the car- 
 minic acid. 
 
 This acid forms a purple mass, fusible and soluble in all proportions in water and in 
 alcohol. Sulphuric and hydrochloric acid dissolve it without alteration. It bears a 
 heat of 136 C. without decomposition. It is very hygroscopic. Its solution forms red 
 precipitates with the alkaline earths, also with the acetates of lead, zinc, copper, and 
 silver. 
 
 According to De la Eue's analysis, carminic acid contains 54 '1 per cent, carbon and 
 4*6 hydrogen, agreeing nearly with the formula C 14 H H 8 . 
 
 Schiitzenberger (Ann. Ch. Phys. [3] liv. 52) regards De la Eue's carminic acid 
 as a mixture, and assigns to pure carminic acid the formula C 9 H 8 5 ; he states also 
 that it is mixed in cochineal with an oxycarminic acid, C 9 H 8 7 , and perhaps also with 
 other acids of intermediate composition. These statements do not appear, however, 
 to be borne out by the results of his analyses. 
 
 Carminic acid is decomposed by chlorine and bromine. The bromine-compound is 
 yellow and soluble in alcohol. 
 
 Carminic acid treated with nitric acid yields nitrococcusic add ; a compound which 
 is isomeric with trinitranisic acid, and crystallises in yellow rhomboidal tables, soluble 
 in cold but more soluble in hot water ; soluble also in alcohol and ether. All its salts 
 are soluble in water. 
 
 The mother-liquor of the preparation of carminic acid contains a crystalline sub- 
 stancp. insoluble in alcohol and ether, soluble in ammonia, and identical with tyrosine. 
 (Warren de la Eue.) 
 
 The colouring principle of cochineal (carmine) was previously obtained in an impure 
 state by Pelletier and Caventou (Ann. Ch. Phys. viii. 250), by treating the cochineal 
 with ether to extract the fatty matter, and digesting the residue in alcohol. 
 
 The fine red pigment known in commerce as carmine, is prepared by treating a 
 solution of cochineal with cream of tartar, alum, or acid oxalate of potassium. The 
 fatty and albuminous matters then coagulate and carry down the colouring matter 
 with them. 
 
 By treating a solution of cochineal with an alkaline carbonate and alum, a compound 
 of the colouring matter with alumina is obtained, known by the name of carmine-lake. 
 
CARMINITE CAROTIN. 805 
 
 For this purpose, the coarser sediment deposited from a decoction of cochineal, after 
 the finer particles have been separated by decantation, is generally used. For cheaper 
 sorts, extract of Brazil wood is sometimes mixed with the cochineal. 
 
 Cochineal colours are used for dying wool and silk crimson or scarlet; but the 
 colours it produces are remarkable more for brilliancy than for durability, and are easily 
 stained by water or alkalis. The mordants used are alum, cream of tartar, and tin- 
 salt. (See Ure's Dictionary of Arts, Manufactures and Mines, i. 616.) 
 
 CARMZXTZTE, or Carmine-spar. A mineral, probably consisting of anhydrous 
 arsenate of lead arid iron, from Hornhausen in Saxony, where it occurs, with Beudan- 
 tite, in quartz and brown iron ore. It occurs in clusters of fine needles, and in sphe- 
 roidal forms with columnar structure, cleaving parallel to the faces of a rhombic prism. 
 Hardness = 2 -5. Lustre vitreous, but pearly on the cleavage faces. Colour carmine 
 to brick-red ; powder reddish-yellow. Translucent. Brittle. Before the blowpipe it 
 gives the reactions of arsenic, lead, and iron. (Dana, ii. 410.) 
 
 CARXVXUFEItXiIC ACID. An acid obtained by Muspratt and Dan son (Phil. 
 Mag. [4] ii. 293), by the action of nitric acid on the aqueous extract of cloves. It 
 separates from the concentrated solution in yellow micaceous scales ; and by precipi- 
 tation with acetate of lead, decomposition of the lead-precipitate with sulphuretted 
 hydrogen, and evaporation, it may be obtained in white crystals. It is insoluble in 
 alcohol, ether, and cold water, soluble in hot water, ammonia, and potash. When 
 heated, it yields a yellow oil and emits an odour of burnt sugar. Strong sulphuric 
 acid does not act upon it in the cold, but carbonises it when heated. A moderately 
 concentrated solution of the acid precipitates the salts of the alkaline earths, forming 
 a very thick gelatinous mass. With copper-salts it forms a green, with silver and 
 ferrous salts a white, and with ferric salts a yellow precipitate, all of flocculent cha- 
 racter. Muspratt and Danson assign to the barium and lead-salts of this acid, the 
 doubtful formula, C* 4 #flf s8 . 
 
 CARKrAI,Z,ITE. KC1.2MgC1.6H 2 O. A salt which sometimes separates in coarse- 
 grained masses, often coloured by oxide of iron, from the mother-liquor of rock-salt, 
 also of certain brine-springs ; it may also be obtained by careful evaporation of the 
 mother-liquor of sea- water. (Jahresber. d. Chem. 1856, p. 884; 1858, p. 739.) 
 
 CAR3TAUBA IV AX. A wax which coats the leaves of the Corypha cerifera, a 
 palm growing in Brazil, and is obtained by drying the leaves and melting the coating, 
 which separates in scales. It forms hard, brittle lumps of yellowish- white colour, in- 
 clining to green, and has an odour of melilot, but no taste. It melts at 97 C., or accord- 
 ing to Lewy (Ann. Ch. Phys. [3] xiii, 438) at 83'5. According to Brande (Phil. 
 Trans. 1811, p. 261), it is insoluble in cold, sparingly soluble in hot alcohol, forming a 
 greenish solution. Similarly with ether. With fixed oils it mixes in all proportions. 
 With caustic potash it forms a pale rose-coloured mass without actually saponifying. 
 Nitric acid converts the wax into a yellow friable mass. Chlorine bleaches it In 
 other respects it behaves like beeswax. According to Lewy, it contains 80'3 per cent, 
 carbon and 13'0 hydrogen. (Handw. d. Chem. 2 te Aufl. ii. [2] 807.) 
 
 CARXTAT. A variety of lithomarge from Eochlitz. (Breithaupt.) 
 
 CARTrEZiZAlT. A subspecies of chalcedony, of white, yellow, brown, and red 
 colour. It has a conchoi'dal fracture. Specific gravity 2-6. Semitransparent, with 
 glistening lustre. The finest specimens come from Cambay and Surat in India. It is 
 found in peculiar strata, thirty feet below the surface, in nodules of a blackish-olive 
 colour, passing into grey. These, after two years' exposure to the sun, are boiled for 
 two days, and thereby acquire the lively colours for which they are prized in jewellery. 
 Caruelian is softer than common chalcedony. It consists mainly of silica (about 94 
 per cent.) with alumina, and a small quantity of sesquioxide of iron. According to 
 Gauthier de Claubry, the colour proceeds, not from oxide of iron, but from an organic 
 substance. This, however, is denied by He in tz. (Pogg. Ann. Ix. 519.) 
 
 CAROXiATHXir. A mineral containing organic matter, found in a coal-mine in 
 Upper Silesia. It has the aspect of honey-stone ; colour, honey-yellow to wine-yellow : 
 translucent on the edges ; has a faint unctuous lustre ; very brittle. Specific gravity 
 1-515. Hardness 2*5. It is decomposed by hydrochloric acid. It contains about 15*10 
 per cent, water, 47'25 alumina, 29'52 silica, and 1-33 carbon. The water is not com- 
 pletely given off below 290 C., at which temperature the organic matter begins to de- 
 compose. The organic matter appears to be allied to humic acid. (Sonnenshein. 
 J. pr. Chem. Ix. 268.) 
 
 CAROTIN. C I8 H 24 0. The colouring matter of the carrot (Daucus Carota\ It 
 was first isolated by Wackenroder in 1831 (Geiger's Mag. xxxiii. 144), afterwards 
 examined by Zeise (J. pr. Chem. xl. 297), and recently with greater exactness by 
 Husemann (Ann. Ch. Pharm. cxvii. 200). 
 
 3 F 3' 
 
806 CAROTIN CARPHOLITE. 
 
 Carrots also contain a colourless substance, hydrocarotin, C^H^O, containing 
 6 at. H more than carotin ; and as they are colourless in the early stages of their 
 growth, Husemann considers it probable that they at first contain only hydrocarotin, 
 which gradually changes to red carotin by oxidation. 
 
 Preparation. The expressed juice of bruised carrots is precipitated with sulphuric 
 acid, to which a small quantity of tincture of galls is added ; the half-dried coagulum is 
 repeatedly boiled with five or six times its volume of 80 percent, alcohol, which extracts 
 the hydrocarotin ; the residue, after drying at a gentle heat, is exhausted with sulphide 
 of carbon ; and the filtrate is mixed with an equal volume of absolute alcohol The 
 solution, when left to itself, deposits the carotin in crystals of the dimetric system, which, 
 while iu the liquid, exhibit a golden-green lustre by reflected light ; if, however, the 
 sulphide of carbon was mixed with much alcohol, or if the solution was too much con- 
 centrated, the crystals are microscopic, and of a ruby-colour. The crystals are washed 
 on a water-bath funnel with boiling 80 per cent, alcohol, afterwards with absolute al- 
 cohol, till the wash-liquid exhibits only a faint yellow colour, and when evaporated on 
 a watch-glass, leaves small octahedral crystals. 
 
 The pure carotin which remains, exhibits, after drying in the air at mean tempera- 
 ture, a red- brown colour with velvet lustre, becoming bright red when dried at 100C. 
 It smells like Florentine violet-root, especially when heated. It is rather heavier than 
 water ; dissolves sparingly in alcohol, ether, and chloroform, easily in sulphide of car- 
 bon, benzene, and volatile oils ; fixed oils dissolve it slowly, with red colour. It be- 
 comes soft at 126 C., and melts at 168 to a thick dark red liquid. 
 
 Carotin forms at low temperatures a colourless crystalline hydrate, which may bo 
 obtained by placing a concentrated solution of carotin in sulphide of carbon (not anhy- 
 drous) in a watch-glass, over a freezing mixture producing a temperature of 10 C. It 
 then separates as a white efflorescence made up of small needles ; but as soon as it is 
 taken out of the freezing mixture, it gives up its water, and is converted into red carotin. 
 The same phenomenon is exhibited by a solution of carotin in benzene, excepting that 
 the hydrate is then slightly yellow. Another hydrate is sometimes formed by adding 
 to a dilute solution of carotin in sulphide of carbon, so much absolute alcohol, that the 
 turbidity at first produced shall disappear, at least on heating the liquid. It separates 
 in thin, iridescent, six-sided laminae, and appears to be more stable than the first-men- 
 tioned hydrate. The composition of these hydrates has not been determined. 
 
 Carotin is very unstable ; during the evaporation of its solution, it often separates in 
 a light yellow amoi'phous modification, which is but sparingly soluble in sulphide of 
 carbon. The red crystals gradually become colourless from without inwards, when 
 exposed to daylight, and more quickly in sunshine ; the new substance thus formed is 
 inodorous, dissolves readily in alcohol or ether, but with difficulty in sulphide of carbon 
 or benzene, and separates from these solutions in the amorphous state. The same 
 change takes place when carotin is exposed for a long time to a heat of 150 C. 
 Whether the new substance thus formed has the same composition as carotin, is not 
 yet made out. Carotin heated to 250 C. forms a mobile liquid, which on cooling soli- 
 difies to a soft yellowish-red mass. At higher temperatures, it carbonises and gives off 
 empyreumatic vapours. 
 
 Fuming nitric acid dissolves carotin with yellow colour, and water separates from 
 the solution a yellow nitro-compound. Strong sulphuric acid dissolves carotin with 
 purple colour ; and on carefully adding water, the colour disappears, and a somewhat 
 modified carotin separates in dark green flocks, which, like carotin altered by light, are 
 coloured brown by sulphuric acid. Sulphurous anhydride changes the colour of carotin 
 to dark indigo, but does not alter it further ; the blue substance crystallises from ben- 
 zene in red cubes, and is also converted into red carotin by boiling with potash. 
 
 I) r// chlorine gas converts carotin into tetrachloro-carotin, a white substance 
 soluble in ether and in sulphide of carbon, becoming soft and dark-red at 100 C., 
 melting at 120. Another substitution-product containing less chlorine appears also 
 to be formed. 
 
 Bromine and iodine likewise decompose carotin, forming substitution -products which 
 are more fusible than carotin itself. 
 
 Carotin is not decomposed by dilute acids, by hydrochloric acid gas, sulphuretted 
 hydrogen, sulphide of ammonium, or by alkalis, either in aqueous or in alcoholic solu- 
 tions. Solutions of carotin are not precipitated by metallic salts ; the alcoholic solution 
 is coloured greenish by ferric chloride. 
 
 A substance having the same colour and composition as carotin, is obtained by treat- 
 ing tribromhydrocarotin, C 18 H 27 Br 3 O, with potash ; but the identity of the two has not 
 yet been completely established. (See HYUROCAROTIN.) 
 
 CASPHOHTE. A silicate of manganese, aluminium, and iron, found near 
 Schlaekeriwald in Bohemia, in radiated and stellated tufts, sometimes also in rhombic 
 of 111 27', and 68 33', with the lateral edges truncated. Specific gravity = 
 
C ARPHOSIDERITE CARROT. 
 
 807 
 
 2-935. Hardness = 5 to 5-5. It is opaque, with straw-yellow or wax-yellow colour 
 (hence the name, from icapQos, straw), and vitreous lustre. Its analysis gives 
 
 A1 4 3 Mn 4 3 Fo 4 s Ca 2 H 2 F. 
 
 SiO 2 
 
 37-53 26-47 
 
 36-15 28-67 
 
 36-15 1974 
 
 18-33 6-27 11-36 = 99-961 (Steimnann). 
 19-16 2-54 0-27 10-78 1-40 = 98-97 (Stromeyer). 
 20-76 9-87 2-56 11*35 =100-43 (Hauer). 
 
 Hence the formula 2R 4 3 .3Si0 2 + 3aq., the sesquioxides of aluminium, manganese, and 
 iron being supposed to replace each other isomorphously. 
 
 By reducing the sesquioxides to protoxides (substituting r = |E), the formula be- 
 comes that of an orthosilicate, 2r 8 O.Si0 2 + aq. = r 4 Si0 4 + aq. According to Kobell, 
 the manganese and iron are in the state of protoxides, and the formula is (Mn 2 0. A1 4 3 ) 
 + 2(H-O.SiO a ). (Eammelsbcrg 1 s Miner alchemic, p. 587.) 
 
 C ARPHOSXDERXTX-:. A hy drated phosphate of iron, containing small quantities 
 of manganese and zinc, occurring in reniform masses and incrustations of straw-yellow 
 colour and resinous lustre. Specific gravity 2 -5; hardness 4 to 4-5. It is found in 
 fissures in mica slate, and was first distinguished by Breithaupt, among some specimens 
 from Labrador. (Dana, ii. 431.) 
 
 CARPHOSTXXiBXTX*:. A straw-yellow variety of Thomsonite, from Bernfiord, 
 Iceland. 
 
 CARPOB AXiS AIV1UIVT. A commercial name of the volatile oil obtained from pi- 
 mento, the fruit of Myrtus pimento,. It is yellowish, heavier than water, and smells 
 like cloves. 
 
 CARROI.ITE. (W. L. Faber, Sill. Am. J. (2) xiii. 418; Smith and Brush, 
 ibid, xvi. 366 ; Grenth, ibid, xxiii. 115.) A sulphide of cobalt and copper, from Finks- 
 burg, Carrol County, Maryland, U. S. Forms homogeneous, very friable masses, 
 with indistinct cleavage ; tin- white to steel-grey colour ; metallic lustre ; iron-black 
 streak ; uneven fracture, approaching to the conchoidal. Hardness 6*5. Specific 
 gravity 4-58. The mineral has not been found in distinct crystals, but appears to belong 
 to the regular system. 
 
 S As Cu Co Ni Fe Quartz 
 
 27.04 1-82 32-99 28*50 1-50 5'31 2-13 = 99-30 (Faber). 
 
 41-29 - 18-15 3770 1-54 1-26 - = 100-08 (Smith and Brush). 
 
 41-71 - 17-55 38-70 1'70 0-46 0-97 = 100-19 (Genth). 
 
 Faber deduces from his analysis (after deducting the nickel, arsenic, and iron, toge- 
 ther with 3"468 per cent, sulphur required to form copper-nickel and magnetic pyrites), 
 the formula Co 2 S.Cu 4 S or CoCcuS. Smith and Brush regard the mineral as cobalt 
 pyrites (Co 3 S 2 ), in which part of the cobalt is replaced by copper. 
 
 CARRAGHEEN MOSS. See CABAQHEEN MOSS (p. 747). 
 
 CARROT. Daucus Carota. The ashes of the root, leaves, and seed of the carrot 
 have been analysed by Way and Ogston (Jahresber. d. Chem. 1849, Table E to page 
 656, and 1850, Table B to p. 660) with the following percentage results : 
 
 
 White Belgian 
 
 Long red Surrey 
 
 
 
 (on poor sandy soil) 
 
 
 Root. 
 
 Leaves. 
 
 Root. 
 
 Leaves. 
 
 Seed. 
 
 p,,tash 
 
 21-40 41-97 
 
 6-55 7'53 
 
 43-73 
 
 17*10 
 
 16*21 
 
 Soda 
 
 8-18 17-53 
 
 946 T2-76 
 
 12-11 
 
 4*85 
 
 1*23 
 
 
 6 08 11 '89 
 
 29 50 34-98 
 
 5' 64 
 
 24'04 
 
 32'96 
 
 
 3-20 5-89 
 
 2 50 3-23 
 
 2'29 
 
 0'89 
 
 V70 
 
 
 059 1-66 
 
 0-90 4-0(> 
 
 0'51 
 
 3-43 
 
 0-84 
 
 
 4-59 9-49 
 0-76 1-92 
 
 5 47 6-68 
 1-83 7-39 
 
 4-26 
 1-11 
 
 5-08 
 11-61 
 
 4*80 
 4*50 
 
 Silicic 
 
 
 15-15 19-11 
 
 14-9222-25 
 
 18 00 
 
 23-15 
 
 15*13 
 
 Phosphoric ,, ..... 
 
 7-86 9-17 
 4-91 7-65 
 
 1-12 2-55 
 8-7715-11 
 
 12-31 
 
 trace 
 
 6-21 
 3-62 
 
 13-38 
 5*24 
 
 
 
 
 99-96 
 
 99-98 
 
 99-99 
 
 Ash per cent, of dry substance 
 
 5-12 8-80 
 
 15-80-21-30 
 
 5-44 
 
 10-03 
 
 4*30 
 
 fresh 
 Moisture in 100 pts. of air-dried substance 
 
 0-77 1-06 
 
 2-85 5-32 
 
 0-47 
 8G-40 
 
 8-73 
 8000 
 
 3-30 
 1300 
 
 Sulphur per cent, in dry substance . 
 
 
 
 
 0-88 
 
 3*05 
 
 CARROT, OXXi OF. Theroot of the carrot contains a very small quantity (O'Ol 14) 
 p<-r rout, of a volatile oil, of specific gravity 0-8863 at 12C., which may be obtained 
 
808 C ARTH AMINE C ARVENE. 
 
 by distilling the fresh roots with water. It has a very strong pungent taste and smell, 
 dissolves sparingly in water, freely in alcohol and in ether. (Wackenroder, Mag. 
 Pharm. xxxiii. 145.) 
 
 C ARTHAMXXI. The colouring principle of safflower ( Carthamus tinctorius\ first 
 examined by Chevreul, afterwards more fully by Schlieper (Ann. Ch. Pharm. 
 Iviii. 362.) 
 
 The flowers of Carthamus tinctorius contain two coloured principles, one yellow, 
 soluble in water, and of no use in dyeing, the other red, soluble in alkalis and preci- 
 pitable by acids from its alkaline solutions : this is carthamin. To prepare it, safflower 
 is first washed repeatedly with water, to free it from the yellow substance, then treated 
 with solution of carbonate of sodium ; the liquid is saturated with acetic acid ; and 
 pieces of cotton are immersed in it, on which the carthamin is deposited. After 
 twenty-four hours, the cotton is removed and treated with solution of carbonate of 
 sodium, which redissolves the colouring matter ; the solution is mixed with citric acid, 
 whereby the carthamin is precipitated in red flocks ; and, lastly, these flocks are dis- 
 solved in alcohol. The solution evaporated in varvuo yields the carthamin in the form 
 of a powder, having a deep red colour with greenish iridescence. It is sparingly soluble 
 in water, insoluble in ether, but easily soluble in alcohol, yielding a fine purple 
 solution. 
 
 According to Schlieper, carthamin contains 56'9 per cent, carbon and 5 -6 hydrogen, 
 agreeing with the formula C I4 H 16 0. 
 
 The yellow colouring matter of carthamus is acid. It has a bitter taste and great 
 colouring power. It combines readily with oxygen, and is converted into a brown 
 substance. It unites with oxide of lea'd, forming the compound (Pb 2 0) 3 .C 8 H 10 5 . 
 
 The red colouring matter of carthamus is used in dyeing, and for the preparation of 
 rouge. The flowers, after being freed as much as possible from the yellow dye by 
 repeated washing with water, are pressed and dried, and sent into the market in the 
 form of cakes, known in commerce as safflower, Spanish red, or China cake, 
 
 For the preparation of rouge, the red colour is extracted by a solution of carbonate 
 of sodium, and precipitated by sulphuric acid or by lemon juice previously depurated by 
 standing. This precipitate is dried on earthen plates, mixed with talc or French chalk, 
 reduced to a powder by means of the leaves of shave-grass triturated with it till they 
 are both very fine, and then sifted. The fineness of the powder and proportion of the 
 precipitate constitute the difference between the finer and cheaper rouge. It is like- 
 wise spread very thin on saucers, and sold in this state for dyeing. 
 
 Carthamus is used for dyeing silk or cotton of a poppy, cherry, rose, or bright 
 orange-red. The cakes of safflower having been disintegrated by steeping in water, 
 the red fibre is washed in sieves as long as the water which runs through acquires a 
 yellow colour. It is then put into a deal trough, and sprinkled at different times with 
 pearl ashes, or rather soda, well powdered and sifted, in the proportion of 6 Ibs. to 100, 
 mixing the alkali well as it is put in. The alkali should be saturated with carbonic 
 acid. The carthamus is then put on a cloth in a trough with a grated bottom, placed 
 on a larger trough, and cold water poured on till the larger trough is filled ; and this 
 treatment is repeated, with addition of a little more alkali toward the end, till the car- 
 thamus is exhausted and become yellow. Lemon juice or sulphuric acid is then poured 
 into the bath, till it is turned of a fine cherry colour, and after it is well stirred, the 
 silk is immersed in it. The silk is wrung, drained, and passed through fresh baths, 
 washing and drying after every operation, till it is of a proper colour ; after which it is 
 brightened in hot water and lemon juice. For a poppy or fire colour, a slight annotto 
 ground is first given ; but the silk should not be alurned. For a pale carnation, a little 
 soap should be put into the bath. All these baths must be used as soon as they are 
 made, and cold, because heat destroys the colour of the red fecula. The colours pro- 
 duced by carthamus are very beautiful, but fugitive. (See Ure's Dictionary of Arts, 
 Manufactures and Mines, i. 624.) 
 
 CARTILAGE. The cartilages consist of a dry flexible tissue, which contains 
 but a small quantity of inorganic matter, and when boiled with water yields chon- 
 drin (q. -y.), a substance resembling gelatin, but differing in certain reactions. 
 
 According to Scherer, the cartilage of the ribs contains 40'5 to 50'9 per cent, carbon, 
 7'() to 7'1 hydrogen, 14'9 nitrogen, and 27'2 to 28'5 oxygen. (See BONE.) 
 
 CARVEWE, CAR VOX., and CARVACROX.. (Volckel, Ann. Ch. Pharm. 
 xxxv. 308; Ixxxv. 246; Schweizer, ibid.}. 329; Gm. xiv. 283, 414.) Essence of 
 caraway consists of two essential oils, carvcnc, C'H 16 , and carvol, C'H I4 0, which may 
 be separated by fractional distillation. The latter, however, is more easily prepared 
 by agitating oil of caraway with an alcoholic solution of sulphide of ammonium : 
 sidpht/drate of carvol, (C 10 H> 4 0) 2 .H 2 S is then formed, and this compound, decomposed 
 by ammonia yields carvol. (Varrentrapp, Handw. d. Chem. 2 te Aufl. ii. [2] 812.) 
 
CARYOPHYLLIC ACID CASE-HARDENING. 809 
 
 Car vena is a colourless mobile oil, lighter than water, having a slight agreeable 
 odour and aromatic taste. Boils at 73 C. It is nearly insoluble in water; very 
 soluble in alcohol and ether ; it absorbs hydrochloric acid, and forms a crystalline com- 
 pound, which melts at 50'5 C. and consists of C 10 H 16 .2HC1. 
 
 Carvol is a liquid boiling at 250 C. Specific gravity 0'953. It is resinised by strong 
 nitric or sulphuric acid, and forms with hydrochloric acid an oily compound containing 
 C'H U O.HC1. Sidphydrate ofcarvol, 2C'H 14 O.H 2 S, crystallises from solution in alcohol 
 in long needles having the lustre of satin; they are fusible, and when cautiously 
 heated, sublime almost unaltered (Varrentrapp). Sulphydrate of sulphocarvol, 
 2C 10 H 14 S.H 2 S, is produced by passing sulphuretted hydrogen for a long time through 
 alcohol in which the preceding compound is suspended. It then separates as a thick 
 oil, which dissolves in ether, and is deposited therefrom in white flocks. The ethereal 
 solution precipitates chloride of mercury and dichloride of platinum ; but the precipi- 
 tates have not a constant composition. (Varrentrapp.) 
 
 Carvacrol, a substance isomeric with carvol, is obtained by treating oil of caraway 
 with potash, or again by treating the same oil with iodine, cohobating several times, 
 and washing the product with potash ; as thus obtained, however, it is mixed with 
 carvene. Carvacrol is also found among the products of the action of iodine on 
 camphor (p. 729), C?"*H I6 + 21 = 2HI + C'H 14 0. Carvacrol when pure is a colour- 
 less viscid oil lighter than water, and soluble in water to a small amount. It has an 
 unpleasant odour, and an acrid very persistent taste. Boils at 232 C., giving off 
 vapours which irritate the organs of respiration. It burns with a bright very smoky 
 flame. 
 
 CARVOPH-7X.X.XC ACID. Syn. with EUGENIC ACID. 
 
 CARirOPHYXiXiX>T. C 10 H 16 0. This substance, isomeric with common camphor, 
 is contained in considerable quantity in cloves, the dried flower-buds of the clove-tree, 
 Caryophyllus aromaticus, which is indigenous in New Guinea and the Moluccas, and 
 cultivated in Sumatra, in the isles of Mauritius and Bourl ion, and in Brazil. It may be 
 extracted by treating cloves with cold alcohol ; the liquid in about fifteen days be- 
 comes covered with crystals, which may be purified with solution of soda. The cloves 
 may also be exhausted with ether, and the caryophyllin separated by agitating the 
 ethereal solution with water. Crude oil of cloves also deposits caryophyllin on 
 standing. 
 
 Caryophyllin forms silky colourless needles arranged in radiating groups, destitute 
 of taste and smell. It melts with difficulty and with partial decomposition (Dumas); 
 sublimes at about 2 : 5 C. (Muspratt). It dissolves sparingly in cold alcohol, easily 
 in boiling alcohol and in ether ; also in hot caustic alkalis. Strong sulphuric acid dis- 
 solves it in the cold without blackening, but the liquid blackens when heated. Nitric 
 acid converts it into a resinous substance. (Gerh. iv. 278.) 
 
 CASCAXiHO. The alluvial soil, consisting of ferruginous sand and clay, in which 
 Brazil diamonds are found. 
 
 CASCARXX.X.A BARK. The bark of cascarilla, Croton cleutheria and Cr. 
 cascarilla, shrubs indigenous in the West Indies. It contains albumin, tannin, a red 
 colouring matter, a fatty substance, an essential oil having an agreeable odour, wax, 
 resin, a gummy substance, starch, pectic acid, wood, fibre, and cascarillin, together 
 with a calcium-salt and chloride of potassium. It possesses tonic and aromatic pro- 
 perties. 
 
 CASCARXXiXiA, OXXi OP. Cascarilla bark contains a volatile aromatic oil, 
 amounting to 0'37 per cent. (Bley), 0*87 (Trommsdorf). It is dark yellow, some- 
 times with a bluish tinge ; of specific gravity 0-9090 938 ; boils at 180 C. or higher 
 (Trommsdorf). According to Volckel, the first distillate is colourless, of specific 
 gravity 0'862, and boils at 173 C. (Gm. xiv. 363.) 
 
 CASCARXXiXfXN is obtained by treating the aqueous extract of cascarilla bark 
 with acetate of lead, filtering, and precipitating the excess of lead with sulphuretted hy- 
 drogen. The liquid evaporated at a gentle heat deposits an amorphous mass, from which, 
 after washing with cold alcohol, the cascarillin may be extracted by boiling alcohol. 
 It is purified by recrystallising several times, after decolorising with animal charcoal. 
 It crystallises in needles or in hexagonal plates, which are colourless, bitter, fusible, 
 decomposible by heat, sparingly soluble in water, more soluble in alcohol, ether, hydro- 
 chloric acid, and sulphuric acid. The aqueous solution is not precipitated by alkalis, 
 tannin, acetate, or subacetate of lead. (Duval, J. Pharm. [3] viii. 91.) 
 
 CASE -HARDENING. Steel when hardened is brittle, and iron alone is not 
 capable of receiving the hardness which steel may be brought to possess. There is, never- 
 theless, a variety of articles in which it is desirable to obtain all the hardness of steel 
 
810 CASEIN. 
 
 together with the toughness of iron. These requisites are united by the art of case- 
 hardening, which does not differ from the making of steel, except in the shorter dura- 
 tion of the process. Tools, utensils, or ornaments intended to be polished, are first 
 manufactured in iron and nearly finished, then put into an iron box, together with 
 vegetable or animal charcoal in powder, and cemented for a certain time. This 
 treatment converts the external part into a coating of steel, which is usually very thin, 
 because the time allowed for the cementation is much shorter than when the whole is 
 intended to be made into steel. Immersion of the heated pieces in water hardens 
 the surface, which is afterwards polished by the usual methods. Moxon (Mechanic 
 Exercises, p. 56) gives the following receipt : Cow's horn or hoof is to be baked or 
 thoroughly dried, and pulverised. To this add an equal quantity of bay salt : mix 
 them with stale chamber ley, or white wine vinegar : cover the iron with this mixture, 
 and bed it in the same in loam, or enclose it in an iron box : lay it then on the hearth 
 of the forge to dry and harden : then put it into the fire, and blow till the lump have 
 a blood-red heat, and no higher, lest the mixture be burnt too much. Take the iron 
 out, aud immerse it in water to harden. 
 
 The same end is now more effectually attained by heating the tool red-hot, and 
 sprinkling over it ferrocyanide of potassium (yellow prussiate) in fine powder, then 
 quenching it in water. Some prefer smearing the surface of the bright iron with loam 
 made into a thin paste, with solution of the yellow prussiate, drying it slowly, then 
 heating it nearly to whiteness, and plunging it into cold water, when the heat has 
 fallen to dull redness. (See Ure's Dictionary of Arts, Manufactures and Mines, i 
 630.) U. 
 
 CASEIN constitutes the chief part of the nitrogenised matter contained in the milk 
 of mammiferous animals. It takes its name from caseus, the Latin name of cheese, which 
 is principally composed of casein mixed with fatty matters (butter) and decomposition 
 products of casein (carbonate of ammonium and ammoniacal salts of acetic, butyric, 
 valeric acids, &c.). 
 
 Preparation. According to the views of Berzelius, Braconnot, and others, two modi- 
 fications of casein are supposed to exist, the one soluble in water, the other coagulated 
 and insoluble in water. Soluble casein has, however, never been prepared free from 
 alkali, and is most probably identical with albuminate of potassium or sodium 
 (Lehmann). Insoluble casein has nearly the same properties and composition as in- 
 soluble albumin. 
 
 Soluble casein may be prepared as follows : Fresh milk, from which the cream has 
 been removed, is evaporated at a gentle heat, a portion of the casein becoming coagu- 
 lated, while the rest remains dissolved. The residue is exhausted with ether, in order 
 to extract fatty substances, and treated with water, which dissolves casein and lactin 
 (sugar of milk) ; a little alcohol is next added to the aqueous solution, whereby most 
 of the lactin is precipitated, the precipitate is washed with weak alcohol, and a solution 
 of casein is obtained which always contains lactin and alkali. (Grerh. iv. 484.) 
 
 Insoluble cast in may be obtained by simply heating creamed milk near to the boiling 
 point, coagulating the liquid with a few drops of acetic acid, completely exhausting 
 the coagulum with water, treating with alcohol and ether, drying and powdering the 
 residue, and repeatedly digesting it with ether (Dumas and Cahours). Perhaps the 
 best method is that of Bopp (Ann. Ch. Pharm. Ixix. 16). Milk is coagulated with 
 hydrochloric acid, the coagulum washed, first with distilled water, and then with water 
 containing 2 or 3 per cent, hydrochloric acid, and finally with cold distilled water. A 
 jelly is thus obtained, dissolving at 40 C. in a large quantity of water. This solution 
 is filtered and carbonate of ammonium cautiously added, and the precipitate is well 
 washed and exhausted with ether-alcohol. Whatever acid be employed in the co- 
 agulation, the casein, when treated in the manner described, never contains any trace 
 of acid, and has always the same composition. (Grerh. loc. cit.) 
 
 Chemical Properties. Soluble casein, when prepared in the manner described, 
 leaves, after evaporation, an amorphous residue, inodorous, but having a sickly taste. 
 It does not redissolve completely in water ; nor does the solution coagulate by heat, but 
 merely becomes covered with a film, which forms again as often as it is removed. 
 Soluble casein is coagulated by alcohol, a portion at the same time entering into solu- 
 tion ; a larger quantity is dissolved by boiling alcohol. The coagulum produced by ab- 
 solute alcohol is completely insoluble in water. Solution of casein is precipitated by 
 all acids (except carbonic acid) ; the precipitates redissolve in an excess of acid, and 
 the solutions become covered with a film when evaporated in an open vessel. Mineral 
 acids precipitate casein from its acetic acid solution. After the coagula thus obtained 
 have been well washed with water, they still redden litmus, although they do not 
 impart an acid reaction to water, even on boiling. The spontaneous conciliation of 
 milk is due to the formation of lactic acid (produced by the fermentation of lactin) the 
 
CASEIN 
 
 811 
 
 acid neutralising the alkali in which the casein was dissolved, and thus rendering the 
 casein insoluble. 
 
 Soluble casein always contains a large amount of mineral matter (when coagulated 
 by alcohol, 8 to 10 per cent.). Casein coagulated by an acid yields from 1 to 5 per 
 cent, ash, and the ash is never alkaline (Scherer). Casein contains phosphate of 
 calcium us a constituent part. Mulder (Arch. f. 1828, p. 155) found in casein 6 per 
 cent, phosphate of calcium, which is precipitated on coagulating any caseous liquid with 
 an acid, although enough free acid be added to dissolve any uncombined phosphate of 
 calcium. 
 
 When moist casein is exposed to the air, it soon begins to putrefy, yielding sulphide 
 and carbonate of ammonium, a neutral oily body, having a disagreeable smell, 
 together with butyric and valeric acids ; at the same time the undecomposed casein 
 dissolves in the ammonia formed (Iljenko, Ann. Ch. Pharm. Ixiii. 264). According 
 to Bopp, a crystalline body possessing a most powerful odour, is formed under the 
 same circumstances. When casein putrefies out of contact with the air, it yields acetic, 
 butyric, valeric, and capric acids, as well as ammonia. 
 
 The following are the results of the analysis of coagulated casein, deducting ash : 
 
 Seherer. 
 
 By alcohol. 
 
 , 537 
 
 . 7-2 
 
 15-6 
 
 By the turning 
 
 of milk. 
 
 54-0 
 
 7-2 
 
 15-7 
 
 By acetic 
 
 acid. 
 
 53-8 
 
 7-4 
 
 157 
 
 Rochleder. 
 
 By sulphuric 
 acid. 
 
 53-8 
 7-1 
 
 Walther. Verdeil. 
 
 1-0 
 
 0-9 
 
 Dumas and Cahours.* 
 
 from 
 
 cow's nvlk 
 by acetic 
 acid. 
 
 From goat's 
 milk, 
 by acetic 
 acid. 
 
 From asses' 
 milk, 
 by acetic 
 arid. 
 
 From sheep's 
 milk, 
 by acetic 
 acid. 
 
 From human 
 milk, 
 by alcohol. 
 
 From Mocd 
 by weak boil- 
 ing alcohol f 
 
 . 53-5 
 
 53-6 
 
 537 
 
 53-5 
 
 53-5 
 
 63-8 
 
 . 7-1 
 
 7-1 
 
 7-1 
 
 7-1 
 
 7-1 
 
 7-1 
 
 . 15-8 
 
 15-8 
 
 16-0 
 
 15-8 
 
 15-8 
 
 15-9 
 
 Carbon 
 
 Hydrogen 
 
 Nitrogen 
 
 Sulphur 
 
 Oxygen 
 
 Carbon 
 Hydrogen 
 Nitrogen . 
 
 Sulphur . 
 
 Oxygen . 
 
 (Gerh. iv. 487.) 
 
 These numbers agree very closely with those obtained by the same chemists in the 
 analysis of albumin, except that casein appears to contain less sulphur than albumin 
 (2-16, Verdeil). Casein does not appear to contain any phosphorus, except in the 
 form of phosphate of calcium. 
 
 Coagulated casein is readily soluble in caustic potash ; after boiling, the solution 
 contains sulphide of potassium. When casein is fused with caustic potash, ammonia 
 is first evolved, then hydrogen ; the mass, at first dark brown, gradually clears and 
 becomes yellow ; it is then completely soluble in water, and contains tyrosin, leucin, 
 valerate (sometimes butyrate), and oxalate of potassium, as well as the potassium-salt 
 of a volatile acid having an excrementitious odour (Li ebig). If a very weak solution 
 of alkali is saturated with casein, the alkaline reaction completely disappears ; the so- 
 lution thus obtained is precipitated by all acids except carbonic. Casein dissolves in 
 a solution of phosphate of sodium, and neutralises it at the same time. It also dis- 
 solves largely in solutions of the alkaline carbonates, of common salt, chloride of am- 
 monium, nitrate of potassium, &c. These solutions do not coagulate by heat, but 
 become gradually covered with a film which is insoluble in dilute alkalis and acids. 
 The same film is formed when milk is heated. 
 
 The solutions of casein are precipitated by all earthy and metallic salts. The pre- 
 cipitates with chloride, sulphate, and acetate of calcium and sulphate of magnesium, 
 are thrown down only on heating the liquid. Compounds insoluble in water and 
 hardening on exposure to the air, are obtained by heating casein with carbonate of 
 calcium or of barium. The compound of casein and lime, prepared from clotted milk, 
 is imputrescible, and is employed in distemper painting. (Orerhardt, loc. cit.} 
 
 If well washed casein, while still moist, be digested with water containing O'OOOS per 
 cent, hydrochloric acid, it dissolves completely. The liquid, filtered from a trace of fat, 
 deflects the rays of polarised light to the left, and has all the characteristics of a solu- 
 tion of albumin. (Bouchardat.) 
 
 * The ashes varind between 1*5 and 5'4 per cent, 
 t See " Physiological Sources of Casein." (p. 812 ) 
 
 The substance was dried 150 C. 
 
812 CASEIN. 
 
 Ozone acts energetically upon casein, the casein being apparently first converted 
 into a substance resembling albumin, which is again destroyed on prolonging the action 
 of the ozone (G-orup-Besanez, Jahresb. d. Chem. 1858, p. 63). 0. Maschke says 
 that he obtained by this reaction a crystallised compound of casein with a new acid 
 (ibid. p. 543). Concentrated hydrochloric acid turns casein blue or violet, forming the 
 same products of decomposition as with albumin. Tannin, from gall-nuts, precipitates 
 the most dilute alkaline solutions of casein. Mercuric chloride yields with soluble 
 casein a bulky white precipitate, soluble in acetic acid and in excess of alcohol : the 
 precipitate does not contain chlorine, and is probably identical with albuminate of 
 mercury (Eisner). Soluble casein is also precipitated by acetate and subacctate of 
 lead, by alum, mercurous nitrate, and sulphate of copper. The acetic acid solution of 
 casein is moreover precipitated by ferrocyanide, chromate, and iodate of potassium. 
 
 Casein yields the same products as albumin with sulphuric acid and acid chromate 
 of potassium or peroxide of manganese (Guckelberger). When chlorine is passed 
 through ammoniacal solution of casein, a product is likewise obtained analogous to that 
 produced in the same way from albumin. 
 
 The coagulation of milk by rennet (the mucous membrane of the fourth stomach of 
 young calves), is supposed by Liebig to result from the animal matter acting as a fer- 
 ment, and transforming the lactin of the milk into lactic acid ; since milk coagulated 
 by rennet at a temperature of 40 C. always has an acid reaction. It appears, how- 
 ever, that milk may be coagulated by rennet, even when rendered alkaline by the 
 addition of small quantities of carbonate of soda, so that after coagulation the liquid 
 still remains alkaline : it is only necessary to operate at a higher temperature (between 
 50 and 60 C.) (Grerh. iv. 490.) 
 
 Sources and physiological nature of Casein. When morbid bile is evaporated, a film 
 of coagulated mucus and of a caseous substance is formed (Frerichs, Hann. Ann. v. 
 pp. 1 and 2). Moleschott (Physiologie des Stoffwechsels, Erlangen, 1S51. p. 366, &e.) 
 found casein in the fluid filling the interstices of cellular tissue-, also in the interstitial 
 fluid of the neck-band. M. S. Schultze found casein in the liquid impregnating the 
 middle lining of the arteries: in 100 pts. of the dried fibrous lining membrane of the 
 wrta thoracica, out of 17'4 23'1 pts. soluble constituents, 7'24 pts. casein ; and in the 
 middle lining of the carotid, which contains more contractile fibrous cells than the aorta, 
 in 39 per cent, soluble pts. 21 pts. of casein were found. The juice of flesh appears to 
 contain casein ; at least this substance has been found in the liquid pressed from flesh 
 It is not certain that blood contains casein. Dumas and Cahours have extracted from 
 the coagulum of blood, a substance which has the same composition as casein (see 
 analysis of casein), but is soluble in warm alcohol (Ann. Ch. Phys. [3] vi. 415). Fre- 
 richs almost always observed in the soluble constituents of the contents of the small in- 
 testine, albuminous compounds sometimes having the properties of albumin, sometimes 
 of casein. A substance resembling casein is extracted by boiling alcohol from the 
 contents of the small intestine of the human fetus, from the fifth to the sixth month 
 (L e hm a n n). The presence of casein in the chyle is exceedingly improbable. (L e h in. ) 
 
 When yoke of egg is treated with ether and water, a coagulum collects under the 
 yellow stratum of ether. If, after removing the ether, the coagulum be filtered off and 
 washed until the wash- water becomes only opaline by heat, a substance remains on the 
 filter identical with casein prepared by Kochleder's or Bopp's method (Ann. Ch. Pharm. 
 xiv. 253 6 ; Bopp, ibid. Ixix. 16 37), only that it contains a little albumin poor in 
 salts; the albumin was precipitated by diluting the yoke solution with water (Gmelin, 
 Handbuch, viii. 2, 282). Casein has been said to exist in urina chyJosa. Eeveil 
 says that the urine of a child twenty-two weeks old, collected in his presence, con- 
 contained all the constituents of milk. Lehmann and Chevalier were unable to 
 confirm this statement. Lehmann does not deny that albuminoi'dal substances may pass 
 into the urine, but with their properties so changed as not to agree with those of any 
 known albuminoidal compound. 
 
 Coagulable albuminate is sometimes found in the discharge of serous skin. Casein 
 is not contained in normal pus, nor has it been detected with certainty in abnormal 
 pus. 
 
 The casein of human milk is stated by Simon to be yellowish-white and very friable ; 
 it absorbed moisture from the air, and was but incompletely precipitated by alum or 
 by acetic acid, from its aqueous solution. Casein from cow's milk is less soluble in 
 water, and becomes viscid and horny on drying. Canine milk gives a casein which 
 does not become viscid and horny when dried, and is less soluble in water. 
 
 The following are the percentages of casein in milk from various sources. (Gfmelin, 
 Handb. viii. [2] 254, 5.) 
 
CASEIN CASSIA. 
 
 813 
 
 HUMAN. 
 
 3-37 (Clemm). 
 27 3-1 (Haidlen). 
 *3924 (Vernois and 
 Becquerel). 
 
 Cow. 
 
 3-0-3-4 (Boussingault) 
 4- Hi average (Playfair). 
 5'52 (Vernois and Bec- 
 querel). 
 
 BITCH. 
 14-6 (Simon). 
 9 7313-6 (Dumas). 
 11-69 (Vernois and Bec- 
 querel). 
 
 Ass. 
 l-95(Peligot). 
 1-70 Gubler and Que- 
 venne). 
 3-57 (Vernois and Bec- 
 querel). 
 
 GOAT. 
 
 4VS2 (Paven). 
 G-03 (Clemm). 
 5-51 (Vernois and Bec- 
 querel). 
 
 Sow. 
 
 8-45 (H. Scherer). 
 7-36 do. 
 Essex sow. 
 
 SHEEP. 
 15-3 (Stipri;ian,Luiscius, 
 and Bondt). 
 G-98 ( V r ernois and Bec- 
 querel). 
 
 MARE. 
 16-2 (Luiscius and 
 Bondt }. 
 3'24 (Vernois and Bee 
 nuerel). 
 
 The soluble casein of milk is rapidly coagulated by the gastric juice, and then gra- 
 dually digested. Milk is the most indigestible of albuminous bodies. A dog digests 
 100 grammes of cheese in 3 3'5 hours ; boiled casein in 7 hours. E. v. Schroder re- 
 marked that in the human stomach, 2 - 5 hours after fresh milk had been taken, casein 
 still remained in the form of amorphous or filmy transparent lumps; and even after 
 the lapse of 3| hours, undissolved milk globules, adhering to small coagula of casein, 
 were almost always found, although the greater part of the milk seemed to have passed 
 from the stomach. Cheeses which are hard, fat, and poor in salts, are more difficult 
 of digestion than loosely coagulated, moist, and fresh cheeses (Grmelin, Handb. iv. 
 [2] 616). The digestibility of casein naturally depends upon its state of aggregation ; 
 the casein of human milk, which coagulates with great difficulty, is more readily 
 digested than that of cow's milk, which is more viscid. C. E. L. 
 
 CASEIN 1 , VEGETABLE. See LEGUMIN. 
 
 CASSAVA. Mousacke, Cassave, Cassava Bread, is a kind of starch, obtained 
 from the root of the maniock (Jatropha manihot, L.) in the West Indies, where this 
 plant is indigenous. The root is grated to a pulp, which is strongly squeezed in bags 
 by a press. The juice contains nearly one-half per cent, of an exceedingly poisonous 
 matter, volatile, and therefore entirely dissipated by the heat on iron plates, to which 
 the pressed and crumbled pulp is exposed. Of that poison, as obtained by distillation, 
 35 drops served to kill, with horrible convulsions, in six minutes, a negro who had been 
 convicted of murder by poison. Cassava may be freed from woody particles by solu- 
 tion, filtration, and evaporation. If in this state it is exposed to heat on an iron plate, 
 it concretes into mammellated small lumps, called tapioca, an agreeable food, which is 
 often imitated by means of potato-starch. 
 
 Cassava flour may be distinguished, by the microscope, from arrow-root, potato- 
 starch, and wheat-starch, by the shape of its particles, which are spherules of j^_ o f 
 an inch in diameter, while those of the second and third farina are ellipsoids, varying 
 in size ; and those of the fourth are spherules, clustered more or less together. U. 
 
 CASSEXi YELLOW. See LEAD, OXYCHLORIDE OF. 
 
 CASSIA CARYOPHYIiLATA. The bark of DicypJiellium caryophyllatum 
 (Nees\ a lauraceous tree growing in Brazil. It has an agreeable taste of cloves, an 
 aromatic odour, and contains, according to Trommsdorff, 19 per cent, resin, 8'0 tannin, 
 10 gum and phosphate of calcium, and 59 woody fibre. It also yields an aromatic 
 volatile oil containing eugenic acid. (Handw. d. Chem. 2 te Aufl. ii. [2] 820.) 
 
 CASSIA. CIOTN'AftlON'EA, Cinnamon Cassia, Chinese Cassia bark, is the 
 bass or inner bark of Cinnamonum aromaticum, a lauraceous tree indigenous in China, 
 and cultivated in Java. It has a burning taste and aromatic odour, and contains, ac- 
 cording to Bucholz, 4-0 per cent, soft resin, 14'6 extractive matter, 64-3 woody fibre, 
 and bassorin; volatile oil, &c. According to Mulder, it also contains tannic acid 
 (Hand wort.) By distillation with salt water, it yields oil of cassia, an oil mainly 
 consisting of cinnamic aldehyde, and nearly identical with the oil obtained from Ceylon 
 cinnamon. 
 
 CASSIA FISTULA. The fruit of Bactyrilobium fistula, a leguminous plant 
 growing in India and in the interior of Africa. According to Vauquelin, it contains 
 14-8 per cent, sugar, and 1*5 gum, together with pectin, gluten, &c. ; according to 
 Caventou, it contains cassiin. The legume is divided into a number of transverse 
 cells, filled with a sweet, slight acid pulp, 100 pts. of which contain, according to Henry : 
 Sugar. Gum. Tanniu. Yellow colouring Water. 
 
 matter and mucus. 
 
 West Indian . 69'2 2'6 3'9 1'3 23-2 
 
 African . . 81-0 67 13'2 19'0 
 
 CASSIA BUDS. The undeveloped flowers of Cinnamonum Louresii (Nees) t 
 By distillation with salt water, they yield oil of cassia. (Handw.) 
 
 * Casein and extractive matter: average of 89 persons (1 932 7 092). 
 
814 CASSIIN CASTOREUM. 
 
 CASSxXXT. A bitter principle obtained from Cassia fistula. It is soluble in water 
 and in alcohol, and is precipitated therefrom by sulphuric, nitric, or hydrochloric acid. 
 (Caventou, J. Pharm. xiii. 340.) 
 
 C ASSITE31ITE. Native oxide of tin. (See TIN.) 
 
 CASSITEROTAWTALITE. Tantalite from Broddbo in Finland, containing 
 oxide of tin. (See TANTALITE.) 
 
 C/LSSrCTS, PURPLE OP. A purple compound of the oxides of gold and tin. 
 (See GOLD.) 
 
 CASSOWIC ACID. A syrupy uncrystallisable acid, .obtained, together with 
 oxalic and saccharic acid, by oxidising cane-sugar with nitric acid. It forms a specu- 
 lum with nitrate of silver. The barium-salt appears to contain C 5 H 6 Ba 2 7 . (Siewert, 
 Institut. xxi. 78.) 
 
 CASTE1TJAUDITE. A mineral from the diamond sands of Bahia in Brazil 
 It consists mainly of hydrated phosphate of yttrium, and occurs in imperfect crystals 
 or irregular grains, probably trimetric, of greyish- white or pale yellow colour, unctuous 
 adamantine lustre, harder than fluorspar, but scratched by a steel point. (Dam our, 
 Institut. 1853, p. 78.) 
 
 C ASTXX.XiO1T A Eli ASTZC A. A Mexican scrophulariaceous plant, which yields 
 caoutchouc. 
 
 C ASTINE. A crystalline basic substance, obtained from the seed of Vitex Agnus 
 castus, L. It is bitter, insoluble in water, soluble in alcohol, ether, and acids ; forms 
 a crystalline hydrochlorate. (Landerer, Buchner's Eepert. liv. 90.) 
 
 CASTOR. A variety of PETALITE (q. V.) 
 
 CASTOREUM. BibergeiL A substance found in a pair of small sacs situated 
 in the genital organs of the beaver (Castor Fiber and Castor amcriclnus). There are 
 three sorts of it, Russian, Bavarian, and American or Canadian. Of these, the Eussian 
 is most valued, though the Bavarian is considered nearly equal to it. Castoreum 
 when fresh, is soft and unctuous, but becomes hard and firm when dry ; it has a black 
 or brownish-black colour, and is somewhat shining. It has a peculiar pungent odour, 
 and a bitterish spicy taste, which irritates the throat ; it is used in medicine as an 
 antispasmodic. 
 
 According to Brandes, Eussian and Canadian castoreum differ considerably in com- 
 position, as shown by the following table : 
 
 Volatile oil I'OO 2'00 
 
 Castoreum resin 13-85 58-60 
 
 Cholesterin 1-20 
 
 Castorin 0-33 2-50 
 
 Albumin . 0-05 1-60 
 
 Glutinous substance . 2'30 2'00 
 
 0-20 2-40 
 
 0-82 0-80 
 
 1-44 1-40 
 
 33-60 2-60 
 
 Extract soluble in water and alcohol ". 
 
 Carbonate of ammonium 
 
 Phosphate of calcium .... 
 
 Carbonate of calcium .... 
 
 Sulphates of potassium, calcium, and mag- 
 nesium 0-20 
 
 Gelatinous substance extracted by potash . 2 '30 8-40 
 
 Gelatinous substance, extractable by potash, 
 
 soluble in alcohol 160 
 
 Membranes, skin, &c, 20'03 3'30 
 
 Water and loss 22-83 11*70 
 
 98-95 100-10 
 
 Wohler by distilling Canadian castoreum with water, obtained phenic acid, together 
 with benzoic acid and salicin ; he suspected also the presence of ellagic and salicylic 
 acid. Lehmann found bile in fresh castoretim, by Pettenkofer's test; also alkaline 
 sebates and urates, and an albuminoi'dal substance. Laugier, Brandes, Batka, and 
 Eiegel, found benzoic acid. Leh-mann found, as the mineral constituents of castoreum, 
 a small quantity of chloride of sodium, sal-ammoniac, and other soluble salts, also 
 phosphate of sodium and ammonium, and an abundance of phosphate of calcium and 
 phosphate of magnesium. 
 
 A substance resembling castoreum is likewise secreted by the prepuce (Praputium 
 penis and ditoridis) of man and of the horse. Lehmann gives the following table of 
 the con i position of : A. Fresh German castoreum ; B. Smoked Eussian ; C.Canadian; 
 D. Srncyma pr&putii of the horse ; E. of man : 
 
CASTORIN CATAPLEIITE. 815 
 
 A. B. C. D. E. 
 
 Ethereal extract ... 7'4 2-5 8-2 49'9 62-8 
 
 Alcoholic extract . . . 677 64-3 41-3 9-6 7'5 
 
 Water extract ... 2'6 1-9 4-8 5-4 6'1 
 
 Acetic acid extract . . 14-2 18-5 21-4 5-4 97 
 
 consisting of 
 
 carbonate of calcium and al- 
 
 buminoi'dal substance . 2-4 3'4 5'8 2-8 5'6 
 
 Portions of skin . . . 57 9-4 18'4 26-8 18-5 
 
 100-0 100-0 99-9 99-9 100-2 
 
 The ethereal extracts contained saponifiable fats, cholesterin, and castorin, and a fat 
 which became very finely divided in water. 
 
 Castor -eum resin is obtained by evaporating the mother-liquor of castorin (vid. inf.) 
 to dryness, exhausting the residue with water, then dissolving in alcohol, and eva- 
 porating. It is black-brown, shining, brittle, nearly insoluble in ether, soluble in 
 aqueous alkalis, and precipitated therefrom by acids. 
 
 Castoreum-oi/, obtained by distilling castoreum with water, is pale yellow, viscid, 
 sparingly soluble in water, easily in alcohol, and has a sharp bitter taste. Russian 
 castoreum yields 2 per cent, of this oil ; Canadian 1 per cent. (Handw. d. Chem. 2* 
 Aufl ii. [2] 1034.) 
 
 CASTORIN. A fatty substance obtained from castoreum. A solution of castoreum 
 in 6 pts. of alcohol saturated while warm, yields on cooling a deposit of ordinary fat, 
 and the mother-liquor deposits crystals of castorin by slow evaporation. This sub- 
 stance, when purified by repeated crystallisation, forms delicate, transparent, four-sided 
 needles, having a faint taste and smell of castoreum. It melts in boiling water, and 
 solidifies on cooling to a hard translucent, pulverisable mass. It is but sparingly 
 soluble in cold alcohol; ether dissolves it readily ; volatile oils only when warm. It 
 appears to volatilise with vapour of water. It dissolves without alteration in boiling 
 dilute sulphuric acid, in strong acetic acid, in caustic alkalis. According to Brandes, 
 it forms a peculiar compound with nitric acid. (Gerh. iv. 280.) 
 
 CASTOR OSXi. This oil, much used in medicine as a purgative, is extracted from 
 'the seed of Eicinus communis, a euphorbiaceous plant cultivated in the West Indies 
 and other warm climates. It is viscid, yellowish, odourless, and has a faint taste, 
 which becomes acrid when the oil is rancid. It solidifies at 18 C. Specific 
 gravity 0-969 at 12 C. It is distinguished from other oils by its easy solubility in 
 alcohol and ether. It is a mixture of several glycerides. When saponified by an 
 alkali, it yields a soap perfectly soluble in water, and from which mineral acids sepa- 
 rate a mixture of acids, oily at common temperatures, and consisting mainly of ricino- 
 leic acid, C 19 H 36 3 . When this oily mixture is dissolved in a third of its volume of 
 alcohol, and the solution is cooled to 15 or 12 C., it deposits a small quantity of 
 nacreous scales, apparently consisting of stearic and palmitic acids. 
 
 Castor-oil gives by analysis : 
 
 Saussure. Ure. Lefort. 
 
 Carbon . . . 74-18 74-00 74-58 74-35 
 
 Hydrogen . . 11-03 10-29 11-48 11-35 
 
 Oxygen . . . 1479 15-71 13-94 14-30 
 
 100-00 100-00 100-00 100-00 
 
 Ammonia converts castor-oil into ricinolamide, N.H 2 .C 19 H 35 2 . When castor oil is 
 distilled with potash, sebate of potassium remains in the retort, and an oily liquid 
 passes over, consisting of caprylic or rcnanthylic alcohol, and methyl-cenanthyl (see 
 ALCOHOLS, p. 98). Castor-oil treated with a mixture of sulphuric acid and acid 
 chromate of potassium, yields cenanthylic acid and hydride of valeryl. Nitric acid 
 attacks it with violence, and converts it into cenanthylic acid. Peroxide of nitrogen 
 causes it to solidify. Castor-oil dissolved in absolute alcohol, and exposed to the action 
 of gaseous hydrochloric acid, is converted into glycerin, and contains ethyl-compounds 
 formed by the fatty acids previously in combination with the glycerin. Castor-oil 
 subjected to dry distillation, yields hydride of cenanthyl and cenanthylic acid, together 
 with small quantities of acrolein and solid fatty acids. (Gerh. ii. 903.) 
 
 CATALYSIS, or Contact action. Terms applied by Berzelius and Mitscherlich 
 to those cases of chemical action in which a substance appears to induce decomposition 
 in another body, without itself undergoing perceptible alteration, or at all events with- 
 out entering into combination with either of the elements of that compound. (See 
 CONTACT ACTION.) 
 
 CATAPIiEZZTE. A silicate containing zirconium, from the island Lamo, near 
 
816 CATAWB ARITE CATECHU. 
 
 Brevig, Norway, together with zircon, leueophane, mosandrite, and tritomite. Ira- 
 perfect prismatic crystals, with perfect basal cleavage. Specific gravity 2'8. Hardness 
 near 6. Opaque, with light yellowish-brown colour, and little lustre. Melts easily 
 to a white enamel before the blowpipe on platinum; gives a colourless glass with 
 borax; blue with cobalt-solution. Dissolves easily in hydrochloric acid without 
 gelatinising. Mean of analyses : 
 
 SiO 2 Zr 4 3 A1 4 8 Na 2 Ca 2 Fe 2 H 2 
 
 46-67 29-57 0'92 10-45 4-13 0'56 8'96 = 101-26 
 
 agreeing nearly with the formula 3(M 2 O.Si0 2 ) + 2(Zr 4 3 .3Si0 2 ) + 2 aq., which if zir- 
 
 conia be regarded as a protoxide (zr = |Zr), may be reduced to that of a metasilicate 
 
 (M'^r 4 )Si 3 9 + aq. (Weibye and Sjogren, Pogg. Ann. Ixxix. 299 ; Dana, ii. 308.) 
 
 CATAWBARXTXi. A name given by Lieber (Sill. Am. J. xxviii. 148), to a 
 rock which accompanies itacolumite, and appears to stand, as a magnesium rock or 
 slate, between itacolumite and itabirite. 
 
 CATECHU, formerly called also Terra japonica, is an extract rich in tannin, 
 obtained by boiling in water the parts of several plants growing in India, and is dis- 
 tinguished into three sorts in commerce. 1. Bombay Catechu, from the Areca 
 catechu, is prepared by boiling the fruit of the areea palm in water, the first portions 
 of the decoction being the strongest, and affording the quality called Cassu, the latter 
 portions, the weaker sort called Coury. The best occurs in dense irregular lumps of a 
 a dark brown colour. It is opaque, with an even, slightly unctuous, shining fracture. 
 Another variety called catechu verum has a somewhat reddish-brown colour, a fatty 
 lustre, a splintery conchoi'dal fracture, and is translucent on the edges. Bombay 
 catechu is almost entirely soluble in boiling water, yielding a dark brown liquor, very 
 rich in tannic acid, and affording copious precipitates with solution of glue and with 
 sulphuric acid. 
 
 2. Bengal Catechu, is obtained from the Acacia (Mimosa) Catechu, by boiling 
 the twigs and unripe pods in water. It has a lower specific gravity, is of a pale brown 
 colour, with a yellowish cast. It is opaque, with a glimmering lustre on the frac- 
 tured surface only, and traversed by dark brown shining stripes. When treated with 
 cold water, it leaves a large residuum, but boiling by water it is mostly taken up ; the 
 solution contains less tannin, but more catechin, than the Bombay sort. 
 
 3. The third kind, called Gambir Catechu, is referred to the Nanclca (Uncarid) 
 Gambir, from which also kino is obtained. It occurs in cubical pieces of 1 to li inches, 
 opaque, and of a brown yellow or bright yellow colour. Their fracture is even and 
 dull. It is little soluble in cold water, but almost completely in boiling water, the 
 solution affording copious precipitates with glue and sulphuric acid. 
 
 4. A fourth kind called Egyptian or Nubian Catechu, is said byLanderer to be 
 obtained by the collectors of gum by boiling the fruits of gummiferous acacias, and 
 to be exposed for sale in the bazaars of Smyrna, and at Constantinople. It is for the 
 most part soluble in water, but differs from the other varieties in many respects. 
 
 All kinds of catechu dissolve in great measure in alcohol ; and soften with heat. 
 The specific gravity of good Bombay catechu is 1-39 ; of Bengal catechu 1-28 ; and of 
 the Gambir variety, 1-40. Catechu is used as an astringent in medicine, and for tan- 
 ning leather, either alone or mixed with oak bark. The comparative value of catechu 
 for tanning may be measured by the proportion of gelatin which is required to precipi- 
 tate all its tannin. Catechu is also used in dyeing, especially for silk and wool. When 
 treated with nitric acid at 45 C., it yields a bright yellow powder, possessing all the 
 properties of picric acid, but much more soluble in water. Silk and wool may be easily 
 dyed in the aqueous solution. 
 
 Catechu has lately been much used to prevent the formation of boiler incrustations, 
 or to remove them when formed ; the quantity required is such as will slightly colour 
 the water. (Newton, Rep. of Patent Inventions, 1858; Dingl. pol. J. cxlviii. 315.) 
 
 Catechu is mainly composed of two principles, catechin and catechutannic acid, 
 together with a brown colouring matter. 
 
 CATECHIN, Catechucic acid, or Tanningenic acid, is obtained from Bengal catechu, 
 by digesting it for 24 hours in cold water to extract the tannin, and then boiling the 
 residue several times with water. The yellow catechucic acid which deposits itself during 
 the cooling is to be collected upon a filter, washed repeatedly with cold water, and 
 finally dissolved in six times its weight of water with purified bone-black to decolorise it. 
 White catechucic acid separates from the hot filtered solution as it cools. It is now 
 to be washed on a filter with cold water, quickly dried on bibulous paper, and more 
 completely under the receiver of the air-pump. Other processes, but less simple, have 
 been prescribed, 
 
 Pure catechin is a white powder composed of very small silky needles. It dissolves 
 in 1133 pts. of water at 17C., forming a colourless tasteless solution, which has no 
 
CATHA EDULIS CATHODE. 817 
 
 effect on the colour of litmus ; it dissolves in 3 pts. of boiling water (forming a solution 
 said to have an acid reaction), in 5 or 6 pts, of cold alcohol, 2 or 3 pts. boiling alcohol 
 120 pts. of cold ether and 7 to 8 pts. boiling ether. According to Zwenger's analysis 
 it contains 61*3 per cent, carbon and4'8 hydrogen, whence Zwenger deduces the formula 
 C 20 H 18 3 . 
 
 Catechin melts at 217 (Zwenger), and solidifies to a translucent, amorphous, brittle 
 mass. After drying at 100 C. it gives off 4 -4 per cent water when melted. When 
 heated above its melting point, it turns brown, and intumesces, giving off water and 
 carbonic acid. By dry distillation it yields an empyreumatic oil and an acid watery 
 liquid, which yields by evaporation crystals of pyrocatechin or oxyphenic acid (q, v.) 
 
 Dilute mineral acids dissolve catechin without altering it ; strong acids decompose 
 it ; with strong sulphuric acid it forms a deep purple liquid. 
 
 Catechin does not form definite compounds with bases. It absorbs ammonia, but 
 gives it up again in vacuo. The fixed alkalis colour it yellow, brown, and black. It 
 does not decompose alkaline carbonates, or precipitate the solutions of hydrate or 
 acetate of calcium or barium. It forms a white precipitate with acetate and subacetate 
 of lead; dark green with ferric chloride; greenish-black or violet with ferroso-ferric 
 sulphate ; brown or black with sulphate of copper; brown or black with salts of silver, 
 gold, and platinum, the metals being reduced. These decompositions often take place 
 after a time only, or on heating the liquid, and are always accompanied by decompo- 
 sition of the catechin. Solutions of gelatin, starch, tartar-emetic, and salts of quinine 
 or morphine, are not precipitated by catechin. (Gerh. ii. 882). 
 
 CATECHTJ-TANNIC ACID. Cachoutannic acid. Tannin of Catechu. To ob- 
 tain this acid, the aqueous infusion of catechu is heated with dilute sulphuric acid, 
 and after the liquid has been clarified from the colouring matter, &c., thereby thrown 
 down, strong sulphuric acid is added as long as a precipitate continues to form. This 
 precipitate is washed on a filter with dilute sulphuric acid, pressed between paper, and 
 dissolved in pure water, the solution digested with carbonate of lead, the solid matter 
 thrown on a filter, and the filtrate evaporated in vacuo. The product thus obtained is 
 purified by re-solution in ether containing alcohol. Another mode of preparation is to 
 exhaust powdered catechu with ether in a displacement-apparatus and evaporate the 
 ethereal solution. A yellowish porous mass then remains resembling gallotannic acid. 
 
 Cachoutannic acid has a purely astringent taste, and resembles gallotanic acid in 
 many of its properties, but is distinguished therefrom by not precipitating tartar- 
 emetic, and by forming a greyish-green precipitate with ferric salts. It does not 
 precipitate ferrous salts. It is soluble in water, alcohol, or ether, insoluble in oils 
 both fixed and volatile ; its solutions are precipitated by gelatin. It is but slightly 
 soluble in water acidulated with sulphuric acid, though more so than gallotannic acid. 
 
 According to Pelouze, catechutannic acid contains C 18 H 18 8 . 
 
 Catechutannic acid softens when heated, and yields by distillation a yellow empy- 
 reumatic oil, together with a watery liquid which gives a greenish-grey precipitate 
 with ferric salts, and is coloured brown by alkalis. 
 
 The solution of catechu-tannic acid alters quickly by exposure to the air, becoming 
 red, and leaving on evaporation a substance which no longer re-dissolves completely iu 
 water. According to Delffs, catechin is one of the products of the decomposition. 
 
 The salts of catechutanuic acid are too unstable to be prepared in the pure state. 
 The potassium-salt is very soluble, and precipitates gelatin after addition of an acid. 
 The catechutannates of the earth-metals and heavy metals form sparingly soluble pre- 
 cipitates. 
 
 CATHA EDULIS. The leaves of this plant, called Kal by the Arabs, are brought 
 from the interior to Aden ; they are said to produce sleeplessness and an agreeable 
 state of excitement. 
 
 C ATH ARTXXfiT. The purgative principle of senna (the leaves and fruits of several 
 shrubs of the genus Cassia, order Leguminosa). It is prepared by evaporating the 
 alcoholic extract of senna, redissolving in water, precipitating with acetate of lead, 
 separating the excess of lead from the solution by sulphuretted hydrogen, and evapo- 
 rating the filtrate. It is a brownish yellow, uncrystallisable, diaphanous mass, soluble 
 in water and alcohol, insoluble in ether ; its taste is bitter and disgusting. By dry 
 distillation it yields products free from nitrogen. Alkalis turn it brown ; with sub- 
 acetate of lead and tincture of galls, it forms yellow precipitates (Lassaigne and 
 Feneuille, Ann.Ch.Phys. [2]xvi. 18). Winckler (Jahrb.pr.Pharm.xix. 223) applies 
 the term cathartin to a bitter substance contained in the berries of the buckthorn 
 (Rhamnus catharticus). (See RHAMNO-CATHARTIN.) 
 
 CATHODE, or Kathode. Faraday's term for the negative pole or electrode in the 
 voltaic circuit, the elements there eliminated being called cations, or Jcations. (See 
 AKION, p. 296.) 
 
 VOL. I. 3 G 
 
818 C ATLINITE CELLULOSE. 
 
 CATI.INTITE. A reddish clay stone from the Coteau de Prairies, west of the 
 Mississippi. (Jackson, SilL Am. J. xxxv. 388.) 
 
 CAT'S EYE. A translucent quartz of beautiful appearance brought from Ceylon. 
 Its colours are green, grey, brown, and red of various shades. Fracture imperfectly 
 conchoi'dal. Translucent, with vitreous internal lustre. It derives its name from a 
 peculiar play of light (chatoyant), arising from fibres interspersed. It scratches quartz, 
 is easily broken, and resists the blowpipe. Specific gravity 2-64. Contains, according 
 to Klaproth, 95 per cent, silica, 175 alumina, 1-5 lime, and 0'25 oxide of iron. It is 
 valued for setting as a precious stone. U. 
 
 CAUIiOPHYXiXiIir. A resinous medicinal preparation obtained in North 
 America from Caidophyllum Halictro'ides. (Buchner's N. Eepert. vi. 188.) 
 
 CAUSTICITY. The quality possessed by strong alkalis, acids, nitrate of sil- 
 ver, &c., of corroding the skin and flesh of animals. In the old language of surgery, 
 caustics were divided in to the actual, such as red-hot iron and moxa, and the poten- 
 tial, such as the above-mentioned preparations. 
 
 CAVOI.INITE. See NEPHELIN. 
 
 C AWX. A miner's term for native sulphate of barium. 
 
 CEDAR, Olli OP (not to be confounded with Oleum de cedro, which is one of the 
 names of oil of citron). A volatile oil obtained from the wood of the Virginian cedar, 
 Juniperus Virginiana, which is used for making pencils, and owes its agreeable odour 
 to this oil. It is a soft semi-solid mass, consisting of a liquid hydrocarbon, cedrene, 
 C 15 H- 4 , and an oxygenated camphor or stearoptene, containing C^H^O. 
 
 To obtain the camphor, the crude oil is distilled; the distillate is pressed between 
 linen or calico, to free it from the greater portion of the liquid cedrene which adheres 
 to it, and then crystallised from alcohol of ordinary strength, which retains the rest 
 of the cedrene in solution. 
 
 Cedar-camphor thus purified is a crystalline mass of great beauty and lustre, having 
 an aromatic odour, like that of pencil -wood, but not much taste. It melts at 74 C. 
 and boils at 282. Vapour-density = 8'4. It dissolves very sparingly in water, but 
 freely in alcohol, whence it crystallises in needles having a silky lustre. It gives by 
 analysis, 81 per cent, carbon and 11 '8 hydrogen, agreeing with the preceding formula'; 
 hence it is isomeric with camphor of cubebs (q. v.) By distillation with phosphoric 
 anhydride, it is resolved into water and cedrene, C 15 H 26 = C 15 H 24 + H 2 0. With 
 pentachloride of phosphorus, it yields an aromatic substance, which has not yet been 
 analysed. Strong sulphuric acid colours it strongly and separates an amber-coloured 
 oil (Walter, Ann. Ch. Phys.[3] I. 1. 498). According to Bertagnini (Compt. rend. 
 xxxv. 800), oil of cedar combines wth the acid sulphites of the alkali-metals. 
 
 CEDRENE. C 16 H 24 . This body is produced from the concrete portion of cedar- 
 oil by the action of phosphoric anhydride. It is oily, aromatic, and has a peppery 
 taste. Specific gravity 0'984 at 15 C. Boils at 248. Vapour-density 7'5 (4 vol.) 
 (Walter, loc. cit.) 
 
 CEDRI7T. See CEDHON. 
 
 CEDRIRET. One of the products obtained by Beichenbach (J. pr. Chem. i. 1) 
 from the tar of beech- wood; said to crystallise in fine needles. Volckel (Ann. Ch. 
 Pharm. Ixxxvi. 331) was not able to find it. 
 
 CEDROCT. Simaba Ccdron (Planchon). A tree which grows in the hottest parts 
 of New Granada, and bears fruits resembling the bean of St. Ignatius ; they have a 
 bitter taste, and are used in that country as medicine. Ether extracts from them a 
 neutral crystallisable fat, insoluble in cold alcohol. The fruit, after exhaustion with 
 ether, yields to alcohol a crystallisable substance, cedrin, which Lewy regards as the 
 active principle of the fruit. Cedrin is sparingly soluble in cold water, more soluble in 
 I -oiling water and in alcohol, and crystallises from the solutions in silky needles. It 
 is neutral, and has an intensely and persistently bitter taste. (Lewy, Compt. rend, 
 xxxii. 510.) 
 
 CEX.ESTICT. Syn. with CCELESTIN. 
 
 CEXiXiUXic ACID. Syn. with METAPECTIC ACID. (See PECTIC ACID.) 
 
 CEI.X.1H.OSE. C^'OO 5 . Ldgnin, Woody fibre. Ligncux. Zellstof, Planzenzett- 
 stojf, PJlanzenfaserstoff. (Pay en, Precis de Chitnic industridle, 4 me ed. ii. 11 ; Gerh. ii. 
 481 ; G m. xv. 123.) This substance constitutes the essential part of the solid framework 
 of plants. The cell-walls in the early stages of their development are composed en- 
 tirely of it, but as the plant grows, they become incrusted with colouring matter, resins, 
 and other foreign substances, which in some parts, as in the heart- wood of large trees, 
 fill up the entire cavities. Some tissues, however, consist almost wholly of cellulose, 
 e. g. the pith of tho rice-paper plant (Acschynomene paludosa\ and the horny peri- 
 
CELLULOSE. 819 
 
 sperms of certain seeds, as those of the phytelephas or vegetable ivory, the date-tree, 
 dragon-tree, &c. Several manufactured vegetable fabrics, as cotton, linen, hemp, and 
 unsized white paper, consist of cellulose very nearly pure. 
 
 Cellulose has also been said to exist in the animal kingdom, constituting the chief 
 part of the mantle of mollusca, and according to Fremy, of the testa or integument of 
 insects and Crustacea ; fiom the analysis of other chemists, however, these substances 
 appear to be nitrogenous (see CHITIN). According to Virchow (Compt. rend, xxxvi. 
 492, 860), cellulose is found in degenerated human spleen and in certain parts of the 
 brain. 
 
 The easiest method of obtaining pure cellulose, is to wash white cotton, unsized 
 paper, old linen, or elder-pith, with a hot solution of caustic potash or soda, then 
 with cold dilute hydrochloric acid, then with ammonia, washing thoroughly with water 
 after the application of each of these reagents, and lastly with alcohol and ether ; it 
 is often necessary to repeat this series of operations two or three times. To obtain 
 pure cellulose from wood, it is necessary, after boiling the wood with potash till the 
 liquid is almost dry, to treat it with chlorine-water or with a weak solution of chloride 
 of lime, repeating these successive operations several times, in order to free the cellular 
 tissue from the encrusting matter which is so intimately united with it. The vege- 
 table fibres in the excrements of herbivorous animals furnish a convenient source of 
 cellulose, because the encrusting matter has been already removed or disintegrated to 
 a great extent by the process of digestion, so that the cellular substance which remains 
 is much easier to purify than the tissue of the plant in its natural state. 
 
 Cellulose thus purified is white, translucent, of specific gravity about 1-5, insoluble 
 in water, alcohol, ether, and oils, both fixed and volatile. When quite pure, it is un- 
 alterable in the air ; but as it exists in wood, in contact with azotised and other easily 
 alterable matters, it gradually decomposes in moist air, undergoing a slow combustion, 
 and being converted into a yellow or brown friable substance called touchwood. 
 
 The state of aggregation of cellulose varies with its origin. In its less compact 
 forms, as in Iceland moss, it is easily disintegrated by boiling with water, and con- 
 verted into a soluble substance, viz. dextrin ; but in its ordinary denser form, as in 
 wood, linen, cotton, &c. it resists the action of water, and even of more energetic 
 solvents, for a long time. 
 
 Strong sulphuric and phosphoric acid disintegrate cellulose at ordinary temperatures, 
 and convert it into dextrin, a substance isomericwith cellulose, without colouring 
 it ; if water be then added and the mixture boiled, the dextrin is converted into 
 glucose. Thin strips of paper or linen, triturated with strong sulphuric acid added drop 
 by drop, are converted, after some time, into a viscous mass consisting of dextrin, and 
 on boiling this mass with water, it acquires the property of reducing copper-salts in pre- 
 sence of an alkali, and after some hours' boiling is completely converted into glucose. 
 
 Unsized paper plunged for a few seconds into sulphuric acid diluted with half to a 
 quarter its bulk of water, and then washed with weak ammonia, undergoes a very re- 
 markable alteration, being converted, without change of composition, into a tough sub- 
 stance very much resembling animal parchment, and applicable to the same purposes. 
 The formation of this remarkable substance was first noticed in 1847, by Messrs. 
 Poumarede and Figuier, who gave to it the name of Papyrin. The discovery re- 
 mained, however, without practical application till the year 1857, when it was again 
 brought into notice and patented in this country by Mr. W. E. Gaine; and the ma- 
 terial, called vegetable parchment, or parchment paper, is now manufactured in large 
 quantity by Messrs. De la Kue and Co. Besides its application to the same purposes 
 as ordinary parchment, it is largely used for covering pots in which preserves and 
 jellies are kept, and for making shirt-collars, imitation lace, &c. &c. ; it is also very 
 useful in the laboratory, for connecting pieces of apparatus in distillations, and as an 
 intervening membrane in experiments of diffusion, osmose, &c. That it should have 
 remained so long unnoticed after its first discovery is probably due to the circumstance 
 that Messrs. Poumarede and Figuier, in preparing it, used strong sulphuric acid, of 
 specific gravity 1'842 ; and it has since been found that the material thus produced, 
 though possessing the general characters above described, is not nearly so tenacious 
 as that obtained with acid diluted to the extent already mentioned, (flofmann, 
 Ann. Ch. Pharm. cxii. 243.) 
 
 Cellulose (linen, for example), boiled for a short time with moderately dilute sul- 
 phuric or nitric acid, is converted into a pulpy mass, which still exhibits the compo- 
 sition of cellulose, and does not dissolve sensibly in water. Strong boiling hydrochloric 
 acid converts cellulose into a fine powder, without change of composition. Moderately 
 strong nitrio acid converts cellulose into a nitro-substitution-product, resembling 
 x y 1 o i' d i n, (^H^NO^O 5 (q. v.} With very strong nitric acid, or a mixture of strong nitric 
 and sulphuric acids, higher substitution -products are formed, viz. C 6 H 8 (N0 2 ) 2 5 and 
 C 6 H 7 (NO-) 3 5 called gun-cot ton, or pyroxylin (q. v.) 
 
 3 G 2 
 
820 CELTIS CEMENT. 
 
 Caustic potash or soda disintegrates cellulose but slowly, and with the more compact 
 varieties the effect is merely superficial. When equal parts of potash and cellulose, 
 moistened with water, are heated in a closed vessel, hydrogen is evolved, and wood- 
 spirit distils over, while formic, acetic, and carbonic acids are produced, and remain 
 with the alkali. Melted hydrate of potassium converts cellulose into malic acid. 
 
 Cellulose in all its forms is immediately blackened by fluoride of boron. 
 
 When chlorine gas is passed into water in which cellulose is suspended, the cellulose 
 is rapidly oxidised, with evolution of carbonic acid ; the same effect is produced on 
 gently heating cellulose with the solution of a hypochlorite : hence in bleaching cotton 
 or linen fabrics, paper-pulp, with hypochlorites, &c., great care must be taken not to 
 use too strong a solution. 
 
 Cellulose in its more compact forms is not coloured by solution of iodine ; but if 
 previously disintegrated by sulphuric acid or caustic alkalis, it produces a violet-blue 
 colour with iodine. In this manner, cellulose may be detected in vegetable tissues 
 under the microscope. Some lichens and algse, Iceland moss for example, give the blue 
 colour with iodine after being boiled with water. 
 
 Solution of Cellulose. Cellulose dissolves completely in an ammoniacal solution of 
 oxide of copper. This solvent may be prepared by passing air freed from carbonic 
 acid into a bottle filled with copper turnings and half filled with ammonia; or by 
 placing copper turnings which have been oxidised on the surface by heating them in 
 the air and then reduced by dry hydrogen, in a tall glass vessel, and causing ammonia 
 to drop through them into a bottle placed below ; or again, by directly dissolving 
 oxide of copper in ammonia. Silver-paper, or thin filtering-paper, dissolves in this 
 liquid after a while, forming a syrupy solution, which may be filtered after dilution 
 with an equal bulk of water. On mixing the liquid thus formed with excess of 
 hydrochloric acid, the cellulose is precipitated in amorphous flakes, which, after washing 
 with water, are colourless and quite free from copper. Even in this finely divided state, 
 cellulose is not coloured blue by iodine, unless it be first subjected to the action of 
 strong sulphuric acid. (Pa yen.) 
 
 Several substances obtained from the solid tissue of plants, and formerly regarded 
 as distinct proximate principles, are now known to be mere modifications of cellulose ; 
 e. g. fungin, from fungi, mcdullin, from the pith of various trees, &c. Hordein, from 
 barley, is a mixture of cellulose with starch and a nitrogenous body. 
 
 CELTIS. The fruit of Celtis orientalis contains 71 per cent, of fleshy pericarp, and 
 28-3 seeds, the latter consisting of 67'3 husks, and 327 kernel ; 100 pts. of the kernels 
 contain 15'2 pts. oil, and 45*6 ash, of which 40'4 pts. consist of carbonate of calcium, 
 and 4-4 of silica. 
 
 CEIVIENT. The term cement is applied to any substance capable of holding' to- 
 gether the surfaces of two bodies without mechanical rivets. Cements may be divided 
 into two classes, stony cements, and those of a resinous and glutinous character. 
 
 1. The chief stony cements are common building mortar, a mixture of lime slaked 
 to a creamy consistence, and sharp sand, which hardens partly by drying, partly by 
 absorption of carbonic acid from the air ; and hydraulic mortar, or Eoman Cement, a 
 mixture of slaked lime with amorphous silica, which hardens under water to a compact 
 mass of hydrated silicate of calcium. (See SILICATES OF CALCIUM.) 
 
 The mastic cement of London, much employed for giving to brickwork the hardness 
 and appearance of stone, is composed of oolitic limestone, chiefly that of Portland, 
 finely ground, mixed with sand and litharge, and made into a loosely coherent paste 
 with linseed oil, either raw or boiled. The oil is extemporaneously mixed by the 
 workman with the cement powder on a board by a trowel, and plastered thinly and 
 smoothly over bricks, laths, or any surfaces which are to resemble stones. The fine 
 dust produced by sawing stone slabs, is said to answer a like purpose, when mixed 
 with litharge and oil. Analysis shows that the said mastic is composed of 35 pts. of 
 siliceous sand, 62 of limestone, and 3 of litharge. These proportions may, however, 
 be somewhat varied without injury. Too much limestone impairs the hardness of the 
 cement ; too much sand makes it porous. For every 100 pts. of such a mixture, about 
 7 of oil are required. As this compost is friable, it may be made more ductile by 
 keeping it compressed in moulds, for a little time before spreading it by the trowel. 
 The surface to which it is to be applied, must be cleaned and oiled beforehand with a 
 brush. It is particularly useful in closing fissures in buildings, and preventing the in- 
 gress of moisture through seams. 
 
 2. Resinous and glutinous cements are of many different compositions. Eosin and 
 beeswax melted together, and thickened with more or less fine brickdust, serve for 
 cementing glass and metal works. Asphalt mixed with chalk in due proportion has 
 been used extensively for paving streets and terraces. The bitumen of Seyssel and 
 Lobsann in France, has been largely employed for this purpose. The compost rendered 
 nearly fluid by heat, is applied to bodies dried, and if convenient, previously heated. 
 
CEMENT. 821 
 
 Coal tar mixed with sand, forms a bad composition, which becomes friable and porous 
 by exposure to weather. 
 
 Seven or eight parts of rosin, and one of wax, melted together and ^ mixed with a 
 small quantity of plaster of Paris, form a very good cement to unite pieces of Derby- 
 shire spar, or other stone. The stone should be made hot enough to melt the cement, 
 and the pieces should be pressed together as closely as possible, so as to leave as little 
 as may be of the cement between them : this is a general rule in cementing, as the 
 thinner the stratum of cement interposed, the firmer it will hold. Melted sulphur 
 used in the same way will answer sufficiently well, if the joining be not required to 
 be very strong. 
 
 It sometimes happens, that jewellers, in setting precious stones, break off pieces by 
 accident : in this case they join them, so that it cannot be easily seen, with gum-mastic, 
 the stones being previously made hot enough to melt it By the same medium, cameos 
 of white enamel or coloured glass are often joined to a real stone as a ground, to pro- 
 duce the appearance of an onyx. Mastic is likewise used to cement false backs or 
 doublets to stones to alter their hue. 
 
 The jewellers in Turkey, who are generally Armenians, ornament watch-cases and 
 other trinkets with gems by glueing them on. The stone is set in silver or gold, and 
 the back of the setting made flat to correspond with the part to which it is to be 
 applied. It is then fixed on with the following cement : Isinglass, soaked in water 
 till it swells up and becomes soft, is dissolved in French brandy, or in rum, so as to 
 form a strong glue. Two small bits of gum galbanum, or gum ammoniacum, are dis- 
 solved in two ounces of this by trituration ; and five or six bits of mastic, as big as 
 pease, being dissolved in as much alcohol as will render them fluid, are to be mixed 
 with this by means of a gentle heat. The cement is to be kept in a phial closely 
 stopped ; and when used, it is to be liquefied by immersing the phial in hot water. 
 This cement resists moisture. 
 
 A solution of shellac in alcohol, added to a solution of isinglass in proof spirit, 
 makes another cement that will resist moisture. 
 
 So does common glue melted without water, with half its weight of rosin, with the 
 addition of a little red ochre to give it a body. This is particularly useful for cement- 
 ing hones to their frames. 
 
 Clay and oxide of iron mixed with oil, are said to form a cement that will harden 
 under water. 
 
 A strong cement, insoluble in water, may be made from cheese. The cheese should 
 be that of skimmed milk, cut into slices, throwing away the rind, and boiled till it be- 
 comes a strong glue, which, however, does not dissolve in the water. This water being 
 poured off, it is to be washed in cold water, and then kneaded in warm water. This 
 process is to be repeated several times. The glue is then to be put warm on a levigat- 
 ing stone, and kneaded with quick lime. This cement may be used cold, but it is better 
 to warm it ; it will join marble, stone, or earthenware, so that the joining is scarcely 
 to be discovered. 
 
 Boiled linseed oil, litharge, red lead, and white lead, mixed together to a proper 
 consistence, and applied on each side of a piece of flannel, or even linen or paper, and 
 put between two pieces of metal before they are brought home, or close together, will 
 make a close and durable joint, that will resist boiling water, or even a considerable 
 pressure of steam. The proportions of the ingredients are not material; but the 
 more the red lead predominates, the sooner the cement will dry, and the more the 
 white, the contrary. This cement answers well for joining stones of large dimen- 
 sions. 
 
 The following is an excellent cement for iron, as in time it unites with the metal into 
 one mass : Take two ounces of sal-ammoniac, one of flour of sulphur, and sixteen of 
 cast-iron filings or borings. Mix them well in a mortar, and keep the powder dry. 
 When the cement is wanted for use, take one part of this mixture, twenty parts of 
 clear iron borings or filings, grind them together in a mortar, mix them with water to 
 a proper consistence, and apply them between the joints. 
 
 Powdered quick lime mixed with bullock's blood, is often used by coppersmiths to 
 lay over the rivets and edges of sheets of copper in large boilers, as a security to the 
 junctures, and also to prevent cocks from leaking. 
 
 Six parts of clay, one of iron filings, and linseed oil sufficient to form a thick paste, 
 make a good cement for stopping cracks in iron boilers. 
 
 Temporary cements are wanted in cutting, grinding, or polishing optical glasses, 
 stones, and various small articles of jewellery, which it is necessary to fix on blocks, or 
 handles, for the purpose. Four ounces of rosin, a quarter of an ounce of wax, and four 
 ounces of whiting made previously red-hot, form a good cement of this kind, as any 
 of the above articles may be fastened to it by heating them, and removed at plea- 
 sure in the same manner, though they adhere very firmly to it when cold. Pitch, 
 
 o G 3 
 
822 CEMENTATION CERANTIC ACID. 
 
 rosin, and a small quantity of tallow, thickened with brick -dust, is much used at 
 Birmingham for these purposes. Four parts of rosin, one of beeswax, and one of 
 brickdust, likewise make a good cement, which answers extremely well for fixing 
 knives and forks in their hafts ; but the manufacturers of cheap articles of this kind 
 too commonly use rosin and brickdust alone. On some occasions, in which a very 
 tough cement is requisite, which will not crack though exposed to repeated blows, as in 
 fastening to a block metallic articles that are to be cut with a hammer and punch, 
 workmen usually mix some tow with the cement, the fibres of which hold its parts 
 together. 
 
 Excellent water-proof cements are made from caoutchouc (p. 739). 
 The following composition is a good cement for electrical apparatus : Five pounds 
 of rosin, one of beeswax, one of red ochre, and two table spoonfuls of plaster of 
 Paris, all melted together. A cheaper one for cementing voltaic plates into wooden 
 troughs is made with six pounds of rosin, one pound of red ochre, half a pound of 
 plaster of Paris, and a quarter of a pint of linseed oil. The ochre and plaster of 
 Paris should be well dried, and added to the other ingredients in a melted state. U. 
 (See Ure's Dictionary of Arts, Manufactures and Mines, i. 641). 
 
 CEMENTATION" is the process by which one solid is made to penetrate and 
 combine with another at a high temperature so as to change the properties of one of 
 them, without liquefaction taking place, being an exception to the general chemical rule, 
 that bodies do not mutually act on each other unless when one or more of them is 
 fluid. The conversion of iron into steel by absorption of carbon into its inmost sub- 
 stance, from a mass of ground charcoal in which it lies embedded while exposed to 
 strong ignition, is one of the best examples of this process. A like change takes 
 place on palladium, iridium, and platinum, in contact with charcoal or silica at a high 
 heat. When a compact mass of the oxide of nickel or iron is ignited in a crucible 
 lined and covered with charcoal, the carbon exerts its deoxidating and metallising 
 power to the very centre. The same phenomenon occurs with compact sulphate of 
 potassium or sodium encased and heated to redness in charcoal, these salts being thereby 
 converted into metallic sulphides. These transformations have been ascribed to the 
 progressive production of the gaseous oxide of carbon, and to its absorption by the 
 metals, or its combination with the oxygen of the oxides or acids. U. 
 
 CE^JSWT COPPER, is the metal precipitated from the blue water of copper 
 mines or works by plunging iron plates into them. (See COPPER.) 
 C33JTAtrilIW. See CNICIN. 
 
 CECTTItAIiIiASSITE. A hydrated silicate of calcium occurring in kidney-shaped 
 lumps, together with other minerals, at Fundy Bay. These lumps are coated with a 
 greenish crust resembling chlorite ; below this crust is a thin layer of cerinite ; within 
 this the centrallassite ; and the central portion consists of cyanolite. Centrallassite ex- 
 hibits a lamellated radiating structure ; it is white or yellowish, translucent, brittle, of 
 specific gravity 2'45 to 2'46, hardness 3'5, and has an almost waxy lustre. It melts before 
 the blowpipe with intumescence to an opaque glass, and forms clear beads with fluxes. 
 It dissolves in hydrochloric acid without gelatinising. Its analysis is said to agree 
 with the formula 8Ca 2 0.15Si0 2 + 5aq. (H. How, Edinb. N. Phil. J. x. 847.) 
 CEPHAI.IS. See IPECACUANHA. 
 
 CEPHAIiOTE. Cerancephalote. A name applied by C ouerbe ( J. Chim. Med. x. 
 624) to a yellow elastic fatty substance, insoluble in alcohol, but soluble in ether, 
 which he obtained from the brain. According to Fremy and J. E. Simon, it is a mix- 
 ture of the cerebrates of potassium and sodium, with traces of olein and oleophosphoric 
 acid. 
 
 CERADIA FUSCATA. A plant indigenous on the coast of Africa, which 
 exudes an amber-brown resin smelling like olibanum. 
 
 CERAIC ACID. An acid containing C 20 H 40 S , said by Hess (Ann. Ch. Pharm. 
 xxvii. 3) to be formed by oxidation in beeswax ; also supposed to be produced in the 
 preparation of oxalic or saccharic acid by the action of nitric acid on wheat-starch ; 
 existing also, according to Oppermann (Ann. Ch. Phys. [2] xlix. 240), in a Brazilian 
 wax. Its existence has not been distinctly proved. 
 
 CERAIxr. A name applied by Boudet and Boissenot (J. Pharm. xiii. 38) to 
 the portion of beeswax which is sparingly soluble in alcohol, and, according to their 
 statement, is not saponified by potash. It appears to be chiefly impure myricin, inas- 
 much as that body is not quite insoluble in alcohol. 
 CERAXrCEPHAX.OTE. See CEPHAT.OTE. 
 
 CER ANTIC ACID. An acid found by Braconnot (Ann. Ch. Phys. [3] xxi. 
 484) in the fuel taken out of an antique lamp, probably of the fourth century. This 
 material was partly soluble in boiling alcohol of 36. The solution on cooling deposited 
 
CERASIN CEREALS. 823 
 
 a white flaky substance melting at 64 C., probably cerin: and the alcoholic mother- 
 liquor retained a substance, which remained after evaporation, as a white, hard, brittle 
 mass, melting at 51 C. ; its alcoholic solution reddened litmus, and by slow evapora- 
 tion deposited small granular crystals. This more soluble substance Braconnot desig- 
 nated cer antic acid. The portion insoluble in boiling alcohol contained myricin. 
 
 CERASIN. The gum which exudes from the cherry-tree, plum-tree, and others 
 of the same family is only partly soluble in water. The soluble portion exhibits the 
 characters of arabin ; the remaining portion, which is called cerasin, merely swells up in 
 water. Cerasin is colourless, semi-transparent, tasteless, and inodorous ; easily pul- 
 verised, uncrystallisable, insoluble in water and in alcohol, not susceptible of alco- 
 holic fermentation. Treated with nitric acid, it yields 15*5 p. c. mucic acid. According 
 to G-elis (Compt. rend. xliv. 144) ordinary gum arabic is converted into insoluble 
 cerasin by a heat of 150 C. This artificial cerasin is reconverted into a soluble gum 
 by prolonged boiling with water, but again becomes insoluble when heated to 150. 
 
 CERASXNE or CERASXTE. Syn. with HORN LEAD. 
 
 CER AS US. The wood of Cerasus avium, the bird-cherry, contains 0'28 per cent., 
 the bark 10-37 per cent, of ash. The constituents of these ashes are as follows : 
 
 K 2 O Na 2 Ca 2 Mg 2 Fe 4 s P 2 a SO 8 SiO 2 Cl 
 Wood. . 25-9 10-4 35-8 11-4 O'l 9'6 4-1 2'5 trace 
 Bark . . 7'9 15-5 447 5'4 0'2 3'5 0'8 21'3 0'4 
 
 The unripe fruit of C. caproniana contains a large quantity of malic acid. 
 
 C. capricida is known in Naples, and C. virginiana in North America, as deleterious. 
 
 CERATE. A mixture of wax with oil or lard, used by surgeons to screen ul- 
 cerated surfaces from the air. Sometimes watery liquids are incorporated with the 
 mass, as subacetate of lead in lead-cerate. U. 
 
 CERAITNTTE. Syn. with NEPHEITE. 
 
 CEREALIW. A nitrogenous substance closely resembling diastase, obtained by 
 Mege-Mouries (Compt. rend, xxxvii. 351; xxxviii. 505; xlii. 1122; xlviii. 431 ; 
 1. 467) from bran. It is contained in the epispermium, the sixth membrane of the seed, 
 reckoning from without, and possesses the power of converting starch into dextrin, 
 sugar, and lactic acid. The brown colour of bread made with flour containing bran 
 appears to be chiefly due to the decomposition of a portion of the flour by the cerealin 
 of the bran (see BREAD, pp. 658, 660). Stiff starch-paste is quickly converted into a 
 thin liquid by an infusion of bran at 40 or 50 C. 
 
 To isolate cerealin, bran is treated for six hours with dilute alcohol, the residue 
 pressed, and this treatment repeated three times, whereby the bran is freed from 
 sugar and dextrin, while the cerealin remains unaltered and undissolved. On treating 
 the residue with water, the cerealin is dissolved, and the aqueous solution evaporated 
 at 40 C. leaves it in the form of an amorphous albuminoid substance easily soluble in 
 water, insoluble in alcohol, ether, and oils. The solution coagulates at 75 C., also on 
 addition of alcohol ; it is precipitated in flakes by dilute acids, not altered by neutral 
 rennet. Its peculiar action on starch is prevented by the presence of alkalis. Cerealin 
 once coagulated is no longer soluble in acids or alkalis, but still possesses the power of 
 transforming starch, though slowly. Cerealin retains its power of decomposing starch 
 at 70 C., but not at higher temperatures, whereas diastase does not lose this power 
 below 90 C. In other respects the two bodies appear to resemble each other exactly. 
 
 According to recent investigation by Mouries, bran freed from cerealin, especially 
 the perispcrmiurn, appears to be more active than cerealin itself, and possesses the power 
 of converting starch even at 100 C. 
 
 CEREAZiS. Cerealia. Getreide. This name is applied to the grasses which are 
 cultivated for human food, viz, wheat, barley, rye, oats, maize, and rice. They 
 are for the most part distinguished by the large quantities of starch, nitrogenous com- 
 pounds, and phosphoric acid contained in their seeds, which constituents it is the object 
 of cultivation to develop as much as possible. The several kinds of cereal grain, ex- 
 cepting rice, contain nearly the same amount of nitrogen ; but in wheat-grain, the 
 nitrogenous matter (gluten) possesses a peculiar adhesiveness, arising from the presence 
 of a glutinous substance called gliadin, which is wanting in the other cereals. It is 
 this property which renders wheat-flour so peculiarly adapted for the making of bread 
 (p. 657). 
 
 From the numerous analyses that have been made of the grain and straw of these 
 plants, we select the following : 
 
 Way and Ogston have determined the amount of water and ash in the grain, 
 straw, and chaff of wheat barley, oats, and rye with the following; results (Journal of the 
 Royal Agricultural Society, vii. [2] 593678 ; Jahresbor. d. Chem. 1849, p. 672): 
 
 3 G 4 
 
824 
 
 TABLE I. Amount of Water and Ash, $c. in Cereals. 
 
 
 
 
 
 
 Weight of 
 
 Species and 
 
 Varieties. 
 
 Moisture in 100 pts. of 
 
 Specific 
 Gravity 
 of the 
 
 Weight 
 bushel 
 
 Ash in 100 pts. of dry 
 
 *- 
 
 Straw Ch.iff. 
 
 
 x ^ 
 
 
 
 Grain < 
 
 in Ibs. 
 
 
 
 
 that of the 
 
 
 Grain. 
 
 Straw. 
 
 Chaff. 
 
 
 
 Grain. 
 
 Straw. 
 
 Chaff. 
 
 Grain = 1000. 
 
 WHEAT : 
 
 
 
 
 
 
 
 
 
 
 
 Hopeton . 
 
 12-00 
 
 13-70 
 
 12-00 
 
 1-374 
 
 60 
 
 2-00 
 
 4-40 
 
 10-43 
 
 1107 
 
 204 
 
 i 9 
 
 12-00 
 
 12-30 
 
 12-00 
 
 ! 342 
 
 59 
 
 2-05 
 
 4-30 
 
 10-58 
 
 987 
 
 206 
 
 . . 
 
 11-00 
 
 12-20 
 
 iroo 
 
 1-354 
 
 61 
 
 1-69 
 
 4-46 
 
 12-74 
 
 1163 
 
 194 
 
 
 
 9-50 
 
 __ 
 
 _ 
 
 1-412 
 
 60 
 
 1-72 
 
 
 
 
 
 m 
 
 11-50 
 
 __ 
 
 _ 
 
 1-356 
 
 56 
 
 1-84 
 
 
 
 
 
 ','... 
 
 11-60 
 
 14-30 
 
 13-50 
 
 1-403 
 
 63 
 
 1-81 
 
 4-77 
 
 14-39 
 
 927 
 
 148 
 
 ^ ^ 
 
 12-00 
 
 13-30 
 
 13-00 
 
 1-382 
 
 61-5 
 
 1-81 
 
 4-92 
 
 16-42 
 
 1009 
 
 156 
 
 . 
 
 12-00 
 
 11-80 
 
 13-00 
 
 1396 
 
 62 
 
 T94 
 
 4-61 
 
 13-55 
 
 1066 
 
 154 
 
 ' 
 
 12-0 
 
 12-00 
 
 11-00 
 
 1-393 
 
 60 
 
 1-92 
 
 5-85 
 
 1364 
 
 1246 
 
 175 
 
 M 
 
 12-50 
 
 13-70 
 
 1150 
 
 1-391 
 
 62 
 
 2-01 
 
 4-82 
 
 11-70 
 
 1167 
 
 185 
 
 
 
 13-00 
 
 __ 
 
 
 
 1-371 
 
 
 
 l-7> 
 
 
 
 
 
 April' 
 
 1 1 -00 
 
 10-80 
 
 12-50 
 
 1-387 
 
 61 
 
 2-01 
 
 4-18 
 
 7-93 
 
 997 
 
 278 
 
 Spring 
 
 12-00 
 
 12-44 
 
 12-21 
 
 1-373 
 
 62 
 
 1-92 
 
 5-79 
 
 18-76 
 
 1155 
 
 175 
 
 
 11-00 
 
 12-00 
 
 11-00 
 
 1 376 
 
 58 
 
 1-95 
 
 5-22 
 
 12-99 
 
 903 
 
 219 
 
 
 
 1300 
 
 14-CO 
 
 12-01 
 
 1-370 
 
 62 
 
 1-83 
 
 4-65 
 
 1634 
 
 1175 
 
 165 
 
 
 
 11-00 
 
 11-73 
 
 11-00 
 
 1-363 
 
 62 
 
 1-79 
 
 6-77 
 
 17-12 
 
 1068 
 
 176 
 
 Bristol reel 
 
 11*0 
 
 12-13 
 
 11-00 
 
 1-370 
 
 61-7 
 
 1-74 
 
 4-46 
 
 13-16 
 
 9G5 
 
 216 
 
 risers red . 
 
 11-00 
 
 11-80 
 
 11-00 
 
 1-3*3 
 
 615 
 
 1-74 
 
 3-61 
 
 8-55 
 
 978 
 
 298 
 
 Rrci-dvff Pantzic . 
 
 12-50 
 
 10-40 
 
 13-00 
 
 1'37 
 
 61 
 
 1-55 
 
 5-43 
 
 1490 
 
 1013 
 
 1*5 
 
 Pip TS thick set 
 
 1350 
 
 12-60 
 
 12-50 
 
 1-350 
 
 61 
 
 1-71 
 
 5-70 
 
 973 
 
 928 
 
 173 
 
 
 
 11-50 
 
 10 50 
 
 12-50 
 
 1-339 
 
 59 
 
 l-!)5 
 
 12-29 
 
 17-12 
 
 568 
 
 194 
 
 White-chaff" . 
 
 11-50 
 
 10-50 
 
 12-00 
 
 1-313 
 
 59 
 
 1-74 
 
 5-30 
 
 11-61 
 
 827 
 
 Io5 
 
 Spacing . 
 
 1200 
 
 10-50 
 
 11-50 
 
 1-377 
 
 61 
 
 2-05 
 
 4-05 
 
 824 
 
 988 
 
 2'23 
 
 \Vliite . 
 
 13-50 
 
 1207 
 
 13-19 
 
 1-308 
 
 60 
 
 1-94 
 
 3-82 
 
 14 97 
 
 1184 
 
 161 
 
 
 13-00 
 
 14-00 
 
 I'2-OO 
 
 1-351 
 
 61 
 
 1-82 
 
 4-65 
 
 15-29 
 
 1009 
 
 178 
 
 . 
 
 12-00 
 
 11-70 
 
 12-00 
 
 1-382 
 
 60 
 
 1-81 
 
 7-92 
 
 16-31 
 
 1122 
 
 207 
 
 Creeping . 
 
 11-50 
 
 10-52 
 
 13-13 
 
 1-375 
 
 62 
 
 T75 
 
 4-83 
 
 1896 
 
 958 
 
 188 
 
 
 
 12-50 
 
 10-46 
 
 12-00 
 
 394 
 
 62 
 
 1-96 
 
 6-14 
 
 17-11 
 
 1071 
 
 116 
 
 
 
 13-00 
 
 12-13 
 
 12-00 
 
 3*7 
 
 61 
 
 2-18 
 
 777 
 
 16-25 
 
 1143 
 
 199 
 
 m , 
 
 13-00 
 
 10-05 
 
 12-00 
 
 376 
 
 62 
 
 1-72 
 
 4-54 
 
 13-60 
 
 1032 
 
 lf,6 
 
 . . 
 
 12-00 
 
 10-84 
 
 13-00 
 
 367 
 
 61-5 
 
 1-93 
 
 4-18 
 
 15-40 
 
 981 
 
 179 
 
 m 9 
 
 11-50 
 
 11-00 
 
 n-oo 
 
 365 
 
 62 
 
 1-95 
 
 4-74 
 
 17-30 
 
 1272 
 
 179 
 
 . 
 
 11-00 
 
 11-93 
 
 V2-00 
 
 372 
 
 62-7 
 
 1-85 
 
 5-22 
 
 14-83 
 
 1279 
 
 186 
 
 . 
 
 11-00 
 
 13-00 
 
 11-00 
 
 391 
 
 63 
 
 1-92 
 
 4-94 
 
 18-50 
 
 1192 
 
 181 
 
 Hammonds 
 
 13-50 
 
 11-00 
 
 16-GO 
 
 354 
 
 60 
 
 2-24 
 
 5-22 
 
 16-32 
 
 932 
 
 191 
 
 Red Britannia . 
 
 12-00 
 
 10-94 
 
 13-00 
 
 369 
 
 62 
 
 2-07 
 
 5-79 
 
 16-64 
 
 730 
 
 169 
 
 Red .... 
 
 11-50 
 
 12-07 
 
 13-50 
 
 1 352 
 
 60 
 
 1-98 
 
 6-42 
 
 15-05 
 
 919 
 
 243 
 
 Rod -.-t raw white . 
 
 11-25 
 
 _ _, 
 
 
 
 1-385 
 
 61 
 
 1-91 
 
 
 
 
 
 > 
 
 12-00 
 
 12-70 
 
 12-50 
 
 1-381 
 
 62 
 
 1-95 
 
 4-85 
 
 11-52 
 
 1050 
 
 178 
 
 
 
 12-50 
 
 11-80 
 
 1400 
 
 1 392 
 
 62 
 
 1-97 
 
 5-30 
 
 16-02 
 
 1327 
 
 203 
 
 
 
 11-50 
 
 12-43 
 
 13-00 
 
 1-362 
 
 61 
 
 1-81 
 
 312 
 
 8-09 
 
 852 
 
 192 
 
 
 
 11-00 
 
 12-30 
 
 12-00 
 
 1413 
 
 63 
 
 1-80 
 
 4-79 
 
 10-73 
 
 1123 
 
 205 
 
 g 
 
 11 00 
 
 13-19 
 
 11-50 
 
 1 -H77 
 
 63 
 
 2-13 
 
 8-47 
 
 17-94 
 
 1313 
 
 197 
 
 > 
 
 12-00 
 
 11-63 
 
 1230 
 
 1-388 
 
 62-5 
 
 1-96 
 
 5-60 
 
 11-00 
 
 982 
 
 180 
 
 >f M * 
 
 12-00 
 
 12-50 
 
 12-50 
 
 1-386 
 
 61 
 
 1-94 
 
 5-79 
 
 12-88 
 
 1165 
 
 240 
 
 French . 
 
 11-00 
 
 _ 
 
 _ 
 
 1-341 
 
 ^_ 
 
 1-74 
 
 
 
 
 
 Egyptian . 
 
 1000 
 
 _ 
 
 
 1 340 
 
 __ 
 
 2-19 
 
 
 
 
 
 Polish . 
 
 11-00 
 
 - _ - 
 
 
 1 355 
 
 _ _ 
 
 1-68 
 
 
 
 
 
 Marianople . 
 
 10-00 
 
 _ 
 
 , 
 
 1-369 
 
 
 
 1-88 
 
 
 
 
 
 Old red Lammas . 
 
 12-50 
 
 
 
 
 
 1-387 
 
 
 
 2-1C 
 
 
 
 
 
 BARLEY : 
 
 
 
 
 
 
 
 
 
 
 
 Unknown variety . 
 
 12-00 
 
 
 
 _ 
 
 
 
 
 
 2-43 
 
 
 
 
 
 Chevalier 
 
 10-00 
 
 _ 
 
 _ 
 
 1-260 
 
 
 
 2-50 
 
 
 
 
 
 9 
 
 1600 
 
 ^ m 
 
 _ 
 
 1-234 
 
 __ 
 
 2-82 
 
 
 
 
 
 Moldavian 
 
 11-00 
 
 __ 
 
 _ 
 
 1-268 
 
 
 
 2-38 
 
 
 
 
 
 9 . 
 
 16-00 
 
 mm 
 
 __ 
 
 __ 
 
 __ 
 
 2-75 
 
 
 
 
 
 Chevalier (awn) . 
 
 15-00 
 
 
 
 
 
 
 
 
 
 14-23 
 
 
 
 
 
 OATS : 
 
 
 
 
 
 
 
 
 
 
 
 Hopeton . 
 
 9-50 
 
 
 
 
 
 
 
 _ 
 
 2-50 
 
 
 
 
 
 Potato . 
 
 10-50 
 
 r 
 
 
 
 1-191 
 
 _ _ 
 
 2-73 
 
 
 
 
 
 
 
 11-00 
 
 . 
 
 _ T 
 
 
 
 
 4-20 
 
 
 
 
 
 Polish . 
 
 11-00 
 
 _ 
 
 
 
 1-752 
 
 
 
 2-97 
 
 
 
 
 
 ... 
 
 13-00 
 
 .^ 
 
 . 
 
 _ 
 
 MM 
 
 3-80 
 
 
 
 
 
 Unknown . 
 
 12-00 
 
 , 
 
 _ M 
 
 . 
 
 T 
 
 3-12 
 
 
 
 
 
 Oat-chaff . . 
 
 15-00 
 
 
 
 
 
 
 
 
 
 9-22 
 
 
 
 1 00 
 
 RYE: 
 
 
 
 
 
 
 
 
 
 
 
 English . 
 
 15-00 
 
 
 
 
 
 
 
 
 
 1-60 
 
 
 
 
 
 In the 50 samples of wheat enumerated in the preceding table: 
 
 The moisture in 100 pts. of grain varies from 95 
 
 straw 
 ;, chaff 
 
 Specific gravity of the grain 
 Weight in Ibs. of 1 bushel of grain 
 of straw to 1000 pts. of grain 
 chaff ,, 
 
 Amount of ash in 100 pts. of dry grain 
 strav 
 
 chaff 
 
 10-4 
 11-0 
 
 730 
 
 116 
 
 1-68 
 
 3-61 
 
 793 
 
 13-5; mean* 11-76 
 
 14-0 11-76 
 
 140 12-24 
 
 1-413 1-374 
 
 63 61-8 
 
 1327 1047 
 
 278 181 
 
 2-19 199 
 
 12-29 5-31 
 
 18-76 , 1395 
 
 * The mean of the whole, not the mean between the extreme limits. 
 
CEREALS. 
 
 825 
 
 i 
 
 6 
 
 | 
 
 cc CN 
 
 M 
 
 CO 
 
 6 
 
 .fa 
 
 1 S 
 
 a 1 
 
 o 
 
 3 
 
 CO g S 
 
 71 j 
 
 66 g 
 
 0-660-98 
 1-031-10 
 
 0-8010*965 
 
 ^ 2 
 1 ? J[ ? 
 
 
 
 ! 1 
 
 1 1 
 
 1 
 
 8 
 
 o> to >n t~ 2 ** 
 
 -<N oo 
 
 82 
 
 %?_,? 
 
 OB 
 
 i? II J2-I IS 
 
 d v 
 
 2 
 
 S S n 
 
 Nitrogen. 
 
 d O* 
 
 ""1 
 
 d 
 
 "'1 
 
 1 ill i l5 II 
 
 S 
 
 I IS 
 
 1 11 
 
 c -o 
 
 43 B 
 
 Nitrogenous 
 Substance. 
 
 3S ^c 
 
 B pl 
 
 82 
 
 I 
 
 I<P | 1 "}? | S'T 
 o ' A 01 ' **** 
 
 1 * 
 
 II 1 1 
 ? -S 
 
 Gum and 
 Sugar. 
 
 
 I IS i I 
 
 1 1 1 1 
 
 1 1 1 1 in 21 
 s 
 
 
 Cellulose. 
 
 i ^sss 1 1 
 
 ii^ 
 
 if 
 
 O "* 
 
 See-" JJ 
 =J -S 
 
 1!|1 | 
 
 fl> s *c S to 
 
 i 
 
 ^eie-icn 
 
 CO <M | 
 
 ir 1 
 
 i * 
 
 Hi 
 
 JS 
 
 i 
 
 00 
 
 <fi 4f | 
 
 "*5 
 
 ^ 
 
 i s 
 
 00 n*5 Q 
 ^ = | 
 
 g-a^ g g 
 
 i 
 
 1 I 
 
 i I 
 
 7"??^7 
 
 SS224 
 
 t ON 
 
 12-4714-13 
 14-86-15-06 
 14-2 
 11-7916-40 
 
 g 
 
 ^^wS 2^ ^^ 
 
 5111 
 jffi ! 
 
 ? 
 
 1 
 
 "3 
 
 
 ? 
 
 l^ll S . 
 
 Name of Species and Varietie 
 
 WHEAT: 
 Winter wheat (Wurtemberg) . 
 22 samples from Lille, Algeria 
 Odessa .... 
 C Old American ... 
 I New Scotch 
 Mean of samples not specified 
 C Summer wheat . 
 ( Winter (9 samples) 
 
 BARLEY: 
 C5 samples (Wurtembe 
 {.'2 free from husk 
 New Scotch . 
 Mean of samples not specified . 
 8 samples 
 
 OATS: 
 
 C6 samples (Wurtember 
 (2 free from husk 
 Shelled grain . 
 9 samples 
 
 .1 . |l . . . 
 
 ?|.i ..11. .... 
 
 Bl 1 S SS fl g 
 
 s|;-s ai;i ^* 
 
 ^t^ IF 1- 
 
 s'- 1 s ^ , .= 
 
 "3. 11 ft 00 
 
 gc|.S |g| || 
 
 s^S 2al 2s 
 
 echnisches Journal, cxxiv. 223 ; 
 xxviii. 85; Jahresber. 1854, p. 79 
 5, 211 ; Jahresber. 1855, p. 889. 
 LXX. 180, 255 ; Jahresber. 1856, p 
 C. The starch includes dextrin 
 m. ci. 12U ; Jahresber. 1857, p. 63 
 
 1 
 
 I 
 
 1 
 l w w . 
 s?c a j| ^; 
 5:8 S g | 
 
 a <2 
 
 Fehling and Faisst.i 
 Poison. 3 
 Poggiale." 
 Mayer. 5 
 
 Fehling and FaSssU 
 
 Poggiale. 4 
 Mayer.* 
 
 |1| ||| || 
 
 ^ u O S ** j 
 
826 
 
 CEREALS. 
 
 T 1 
 
 s r 
 
 J ssass s a s ill 
 
 ^. (O 
 
 co ep 
 
 1 ! 
 
 2 
 
 1* 
 
 a 
 
 i I 
 
 11 1 1 1 1 1 
 
 | 9 
 
 iftOOO'9' "T 
 
 555S 4 
 5? 
 
 ' ' 
 
 1 I I 
 
 3 
 
 11 
 
 <* 
 
 '(N J 1 
 
 5P 
 
 1 -. 7 9 W(N 
 
 io ,1 J obb 
 
 6 6 
 
 I 
 
 6 
 
 s^ 
 
 s 
 
 000 
 
 b o 
 
 $ S 5 
 
 7-r 7 Hf 
 
 i= i i 
 
 
 
 o - 
 
 16 
 P 
 
 i 
 
 pecie 
 
 Nam 
 and 
 
 
CEREALS. 
 
 827 
 
 O 
 
 
 n c* 
 
 1 
 
 00 CO 
 
 3poo .-. <r> p at 
 ^nn n i. ri 
 
 p 
 
 to <p 
 
 r i 
 
 T Sli 1 i-S 3 
 
 I 1 
 
 
 
 g 
 
 
 6 
 
 1 1 1 1 1 III 
 
 1 1 
 
 S 8 
 I | TV v 9* "P 7* 
 
 4 .122 S 8 S3 8 
 
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CEREBRIC ACID CEREBRIN. 829 
 
 Way and Ogston deduce from their analyses of the ash of cereals the following 
 general conclusions : 
 
 The amount of ash is not influenced in any definite manner by the nature of the 
 soil ; it appears, however, to be greatest on clay soils, less on calcareous, and least on 
 sandy soils. The strongest straw contains the largest amount of ash. The amount of 
 ash in the chaff varies in proportion to that in the straw, not to that in the grain 
 (see Table I.). The amount of ash in the grain varies between much narrower limits 
 than that of the straw or chaff. It varies as much in different samples of grain grown 
 on the same soil us in samples from different soils, and bears no definite relation either 
 to climate or to variety. But in all cases that were examined, the proportion of ash 
 in the grain was found to vary inversely as the total weight of grain in the crop ; 
 whence it would appear that the amount of mineral constituents abstracted from the 
 soil by the grain is the same whatever may be the actual weight of the crop. 
 
 Not only the amount, but likewise the composition of the ash appeals to be inde- 
 pendent of the nature of the soil : the predominance of any constituent, lime or silica, 
 for example, in the soil by no means leads to a predominance of that same constituent 
 in the plant. Neither does it appear that different bases have any tendency to replace 
 one another in plants. An abundance of soda in the soil or the manure does not cause 
 that alkali to take the place of potash in the plant. Other chemists have, however, 
 arrived at different conclusions relating to this point. (See Daubeny, Chem. Soc. 
 Qu. J. v. 9; xiv. 215. Malaguti and Durocher, Ann. Ch. Phys. [3] liv. 257.) 
 
 The difference in the amount of ash in the grain, straw, and chaff relate only to the 
 silica ; if this be deducted, the remainders exhibit no perceptible difference. 
 
 The ash of the grain of barley and oats differs from that of wheat-grain only in the 
 much larger amount of silica contained in the two former ; if this be deducted, all es- 
 sential differences vanish. 
 
 For further details, see the names of the several cereals (BAELET, under HOBDEUM) ; 
 also the articles SOILS and MANURES. 
 
 CEREBStTC ACID. (Fremy, Ann. Ch. Phys. [2] Ivi. 168; v. Bibra, Ver- 
 
 gleichende Untcrsuchungenltbcrdas Gehirn der Mtnschtn und der Wirbelthiere, Mann- 
 heim, 1854.) A fatty acid contained in the brain. It is obtained by cutting brain 
 into thin slices ; treating it repeatedly with boiling alcohol to deprive it of water ; 
 pressing it ; digesting first with cold then with warm ether ; distilling off the ether 
 from the solution ; and digesting the slimy residue with a much larger quantity of 
 ether. Cerebric acid then remains as a sodium-salt mixed with phosphate of calcium, 
 oleo-phosphoric acid in the form of a sodium and calcium-salt, and brain-albumin. 
 To purify the product, it is digested in boiling absolute alcohol slightly acidulated with 
 sulphuric acid, which leaves the calcium and sodium undissolved as sulphates, while 
 the alcohol takes up the cerebric and oleo-phosphoric acids, and deposits them on 
 cooling. Lastly, the mixture is washed with cold ether, which dissolves the oleo- 
 phosphoric acid and leaves the cerebric acid, which is finally purified by recrystal- 
 lising it several times from boiling ether. 
 
 Cerebric acid has a white, granular, crystalline aspect ; it is soluble in boiling al- 
 cohol, insoluble in cold ether, easily soluble in boiling ether ; in boiling water it swells 
 up, but does not dissolve. It melts at a temperature near that at which it begins to 
 decompose, and when more strongly heated burns with a characteristic odour, leaving 
 a difficultly combustible charcoal with a decided acid reaction. It consists, according 
 to Fremy, of 667 per cent, carbon, 10'6 hydrogen, 2*3 nitrogen, 0'9 phosphorus, and 
 19 -5 oxygen. According to Miiller and v. Bibra, the phosphorus is not an essential 
 constituent. 
 
 Cerebric acid is a weak acid, but nevertheless forms salts with all bases. The am- 
 monium-, potassium-, and sodium-seUta are obtained as precipitates, nearly insoluble in 
 alcohol, by placing an alcoholic solution of cerebric acid in contact with the respective 
 alkalis. Baryta, strontia, and lime unite directly with cerebric acid, and deprive it of 
 its property of forming an emulsion with water. 
 
 CEREBRXN'. This name has been applied to several substances obtained from 
 brain. Fourcroy in 1793 (Ann. Chim. xvi. 283) obtained a substance which was 
 called cerebriu, brain-fat, or phosphoretted bile-fat, and was probably a mixture of 
 Fremy's cerebric acid with the substance which separates after some time from al- 
 cohol in which anatomical preparations containing nerves or brain have been pre- 
 served. Chevreul applied the same term to a substance obtained from blood-serum, 
 probably a mixture of fats and glycerides containing phosphoric acid. Lastly, Gob ley 
 (J. Pharm. [3] xviii. 107) designates as cerebrin, a substance obtained chiefly from 
 carp's eggs, and agreeing essentially in composition and property with Fremy's cere- 
 bric acid, excepting that it does not exhibit any tendency to combine with .bases. 
 
 W. Miiller (Ann. Ch. Pharm. cv. 361) has obtained a substance analogous to 
 
830 CEREBROL CERIN. 
 
 Fr^my's cerebrin, by triturating brain to a thin pulp with water, heating the mixture 
 to the boiling point, and treating the separated coagulum with boiling alcohol. The 
 alcoholic extract filtered at the boiling heat deposits a mixture of cholesterin and cere- 
 brin, together with other substances ; and on treating this mixture with cold ether, 
 cerebrin remains behind, and may be purified by repeated crystallisation from boiling 
 alcohol. It then forms a snow-white powder composed of microscopic spherules, agree- 
 ing with Fr^my's cerebric acid in most of its properties, especially in swelling up in 
 water like starch, and forming an emulsion. It contains 68-45 per cent, carbon, 11-20 
 hydrogen, 4'51 nitrogen, and 15-66 oxygen, whence Muller deduces the empirical for- 
 mula C I7 H 33 NO S . It does not dissolve in alkalis or in dilute acids, but is decomposed 
 at the boiling heat by hydrochloric, sulphuric, and nitric acid. The product of its 
 decomposition by nitric acid is a non-azotised white waxy body, soluble in alcohol and 
 ether. Treated with strong sulphuric acid in the cold, it dissolves with dark purple- 
 red colour, and the solution mixed with a large quantity of water becomes colourless, 
 and deposits a yellowish, tenacious, flocculent substance. 
 
 It is most probable that the cerebrin of Gobley and Muller, the cerebrote of Couerbe, 
 and the cerebric acid of Fremy and v. Bibra contain, as their essential constituent, 
 one and the same substance, which is likewise present in cephalote and stearoconote. 
 (Handw. d. Chem. 2 te Aufl. ii. [2] 888.) 
 
 CEREBROXi (Berzelius). Eleene-cerebrol (Couerbe). An oily reddish sub- 
 stance, insoluble in water, soluble in alcohol and ether, obtained by Couerbe 
 (J. Chim. md. ii. 765 ; x. 524) from brain. According to Frmy, it is a mixture of 
 olein, oleo-phosphoric acid, cholesterin, and cerebric acid. 
 
 CEREBRO-SPIN.A.Ii n,iTII>. A serous fluid contained in the sub-arachnoidal 
 cavities, and forming a liquid atmosphere round the brain and spinal marrow. It 
 belongs to the class of serous transudates, and is generally distinguished by its very 
 small amount of solid constituents, especially of organic matter. These constituents 
 are albumin, traces of fat, extractive matter, and the inorganic salts of blood-serum. 
 It contains also a substance which reduces cupric salts, but differs from glucose in not 
 being resolved into alcohol and carbonic acid by fermentation. According to F. 
 Hoppe (Chem. Centralbl. 1860, p. 42) this substance is soluble in water and in abso- 
 lute alcohol, does not crystallise, either per se or with chloride of sodium, is not precipi- 
 tated either by neutral or basic acetate of lead alone, but yields a precipitate with the 
 latter in presence of ammonia. It is decomposed by putrefaction. 
 
 Hoppe and Schwaberg analysed the cerebro-spinal fluid obtained by puncturing in 
 two cases of Spina bifida and two of Hydrocephalus intcrnus, with the following re- 
 sults : 
 
 Spina bifida. Hydrocephalus. 
 
 Water . 
 Soiled matter 
 
 Albumin 
 
 Extractive matter 
 Soluble salts . 
 Insoluble salts 
 
 Puncture. II. Puncture. I. Puncture. II. Puncture. 
 
 989-33 989-80 979-01 989-53 
 
 10-67 10-20 20-99 10-47 
 
 0-25 0-55 11-79 0-70 
 
 2-30 2-00 1-32 1-57 
 
 7-67 7-20 7-54 7'67 
 
 0-45 0-45 0-35 0-53 
 
 The fluids from the Spina bifida were strongly alkaline and perfectly transparent. 
 The first reduced cupric oxide, the second did not. The second hydrocephalic liquid 
 also exhibited the reducing action. The greater amount of albumin in the first hydro- 
 cephalic liquid was due to previous inflammation of the transudent vessels. (Hanchv. 
 d. Chem. ii. [2] 891.) 
 
 CEREBROTE. (Couerbe, Ann. Ch. Phys. [2] Ivi. 164.) Brain-wax, Hlni- 
 wachs (L. Grmelin), Marfcpulver, Myelocone (Kiihn.) A substance containing sul- 
 phur and phosphorus, which Couerbe obtained by treating the deposit which separates 
 from the alcoholic and ethereal extracts of the brain with ether ; cholesterin then dis- 
 solves, and the so-called cerebrote remains. According to Frmy, it is merely a 
 mixture of cerebric acid with small quantities of cerebrate of potassium and brain- 
 albumin. 
 
 CERic ACZX>. An acid obtained by treating cerin, the waxy matter of cork, 
 with nitric acid, washing with water, dissolving in alcohol, filtering and evaporating. 
 It is a brownish diaphanous waxy mass, which softens at a gentle heat, and melts 
 below the boiling point of water. Dissolves readily in alkalis. Yields empyreumatic 
 products when heated. Contains 64-2 per cent, carbon, 8-8 hydrogen, and 27'0 oxygen. 
 With acetate of lead it forms a white precipitate containing 51'1 C, 6-9 H, 19-2 Pb 2 O, 
 and 22-8 0. (Dopping, Ann. Ch. Pharm. xlv. 289.) 
 
 CERZTT. A waxy substance extracted by alcohol or ether from grated cork, pre- 
 viously freed from the outer crust. It separates from the solution in yellowish needles, 
 
CERINE CERIUM. 83 1 
 
 which may be obtained colourless by recrystallisation. Contains 74-95 carbon, 10-55 
 hydrogen, and 14*5 oxygen, agreeing nearly with the empirical formula C 25 H 40 3 . 
 Cerin softens in boiling water and falls to the bottom. It is not attacked by boiling 
 potash. Thrown on glowing coals, it volatilises like beeswax, giving off white fumes. 
 By dry distillation it yields a little acid and a large quantity of an oil which solidifies 
 on cooling ; it leaves but little charcoal. Treated with hot nitric acid it yields eerie 
 acid, together with oxalic and carbonic acids. Cork contains from T8 to 2 -5 per cent. 
 of waxy matter. (Chevreul, Ann. Chim. xcvi. 170; Dopping, loc. cit.) 
 
 The name cerin was also applied by John to the portion of beeswax which is soluble 
 in alcohol ; but according to Brodie, the substance thus designated is merely impure 
 cerotic acid (a. v.) 
 
 CERIKTE or A.LI.ANITE. See ORTHITE. 
 
 CERITJIW. A waxy fat obtained from the lignite of Grerstewitz near Merseberg, 
 of which it forms about 18 per cent. Contains 76'7 to 78*1 C, and 11-1 to 12'3 H. 
 Plastic at common temperatures ; melts at 100 C. ; sparingly soluble in alcohol ; not 
 saponifiable ; yields a crystalline product by distillation. (Wackenroder, Ann. Ch. 
 Pharm. Ixxii. 315.) 
 
 CERITE. A hydrated silicate of cerium, containing also lanthanum and didy- 
 mium. It is the chief source of cerium, and is the mineral from which that metal 
 was first obtained. It is found only in an abandoned copper mine at Kiddarhytta in 
 Westmanland, Sweden, occurring in compact fine-grained masses of indistinct blackish 
 red colour; also in short six-sided prisms. Specific gravity 4 '9 3. Hardness 5*5. 
 Before the blowpipe it gives off water, but does not melt. It is completely decomposed 
 by hydrochloric acid, leaving a residue of silica. According to Kjerulf (Ann. Ch. 
 Pharm. Ixxxvii. 12) it does not give off a trace of chlorine when treated with hydro- 
 chloric acid, and consequently the cerium exists in it wholly as cerous oxide. Kjerulf 
 found it to contain : 
 
 SiO 2 Ce 2 a Fe2 Ca2 H2 MoS BiS 
 
 20-40 56-07 8-12 4-77 M7 5-29 3-27 0-18 = 99-27 
 
 whence may be deduced the formula 2M 2 O.Si0 2 + aq. or M 4 SiO* + aq. It generally also 
 contains a small quantity of yttria. 
 
 CERIUM. Symbol Ce. Atomic Weight 46. This metal, which was discovered 
 in 1803, simultaneously by Klaproth and by Hisinger and Berzelius, exists, together 
 with lanthanum and didymium, in cerite, allanite, orthite, yttro-cerite, and a few other 
 minerals, all of somewhat rare occurrence. The most abundant of them is cerite (vid. 
 sup.) To extract the oxides of the three metals, the cerite is finely pounded and 
 boiled for some hours with strong hydrochloric acid, or aqua-regia, which dissolves the 
 metallic oxides, leaving nothing but silica. The filtered solution is then treated with 
 a slight excess of ammonia, which precipitates everything but the lime ; the precipi- 
 tate is redissolved in hydrochloric acid, and the solution treated with excess of oxalic 
 acid. A white or faintly rose-coloured precipitate is then obtained, consisting of the 
 oxalates of cerium, lanthanum, and didymium : it is curdy at first, but in a few minutes 
 becomes crystalline, and easily settles down. "When dried and ignited, it yields a red- 
 brown powder, containing the three metals in the state of oxide. The finely pounded 
 cerite may also be mixed with strong sulphuric acid to the consistence of a thick paste, 
 the mixture gently heated till it is converted into a dry white powder, and this powder 
 heated somewhat below redness in an earthen crucible. The three metals are thus 
 brought to the state of basic sulphates, which dissolve completely when very gradually 
 added to cold water; and the solution treated with oxalic acid yields a precipitate of 
 the mixed oxalates, which may be ignited as before. 
 
 From the red-brown mixture of the oxides of cerium, lanthanum, and didymium 
 thus obtained, a pure oxide of cerium may be prepared by either of the following pro- 
 cesses : 1. The mixed oxides are heated with strong hydrochloric acid, which dis- 
 solves the whole, with evolution of chlorine; the solution is precipitated with excess of 
 caustic potash ; and chlorine gas passed through the liquid with the precipitate sus- 
 pended in it. The cerium is thereby brought to the state of ceroso-ceric oxide, which is 
 left undissolved in the form of a bright yellow precipitate, while the lanthanum and 
 didymium remain in the state of protoxides, and dissolve. To ensure complete separa- 
 tion, the passage of the chlorine must be continued till the liquid is completely saturated 
 with it, and the solution, together with the precipitate, left for several hours in a 
 stoppered bottle, and agitated now and then. The liquid is then filtered, the washed 
 precipitate treated with strong boiling hydrochloric acid, which dissolves it with evo- 
 lution of chlorine, and forms a colourless solution of protochloride of cerium ; and this, 
 when treated with oxalic acid or oxalate of ammonia, yields a perfectly white precipitate 
 
832 CERIUM. 
 
 of oxalate of cerium, which may be converted into oxide by ignition (M o sender). 
 
 2. The red-brown mixture of the three oxides is treated with very dilute nitric acid 
 (1 pt. of nitric acid of ordinary strength to between 50 and 100 pts. of water), which 
 dissolves the greater part of the oxides of lanthanum and didymium, and leaves the 
 oxide of cerium ; and by treating the residue with very strong nitric acid, the last 
 traces of lanthanum and didymium maybe extracted (Mosander, Marignac). 
 
 3. The red-brown mixture of the three oxides is boiled for several hours in a strong 
 solution of chloride of ammonium. The oxides of lanthanum and didymium then dis- 
 solve, with evolution of ammonia, and sesquioxide of cerium is left in a state of purity. 
 It must be collected on a filter and washed with a solution of sal-ammoniac, because, 
 when washed with pure water, it first runs through the filter, and then stops it up 
 (Watts, Chem. Soc. Qu. J. ii. 147). 4. Oxalate of cerium obtained as above is mixed 
 with half its weight of pure magnesia, and made up into a stiff paste with water ; and 
 this mixture when dry is heated to low redness in a porcelain basin, with constant 
 stirring. The product is a cinnamon-coloured powder, containing the whole of the 
 cerium as eerie (? ceroso-ceric) oxide, in combination with magnesia, oxide of lantha- 
 num, and other protoxides. It dissolves completely, with aid of heat, in strong nitric 
 acid, forming a deep brown solution of a double salt, which appears to consist of eerie 
 nitrate in combination with cerous nitrate and the nitrates of lanthanum, didymium, 
 and magnesium, sometimes also a small quantity of nitrate of yttrium. This double 
 salt separates in splendid rhombohedral crystals having nearly the colour of acid 
 chromate of potassium. The solution, if diluted with water before these crystals 
 have separated, does not yield any precipitate, either in the cold or in boiling ; but if 
 the crystallisation be allowed to go on till lighter-coloured laminated crystals separate 
 containing magnesium and lanthanum with very little cerium, the mother-liquor then 
 deposits, on dilution and boiling, a basic salt of cerium free from all other metals. 
 The precipitate is not formed so long as the red double salt remains dissolved in the 
 liquid ; indeed it redissolves on adding to the liquid a solution of that salt. The liquid 
 from which the cerium precipitate has separated still retains cerium, which may be 
 separated by repetition of the treatment. 
 
 To separate the cerium from the solution of the red salt, it is diluted with a large 
 quantity of water, then boiled, and sulphuric acid added in small quantity as long as 
 the resulting precipitate is thereby increased. The cerium is then precipitated as a 
 yellowish-white, flocculent basic salt, containing both nitric and sulphuric acids, but 
 free from all other metals, which is difficult to wash on a filter, but is easily washed by 
 decantation with water slightly acidulated with sulphuric acid. This salt dissolves 
 readily in strong sulphuric acid, and the solution, after reduction with sulphurous 
 acid, yields, with oxalic acid, a white precipitate of pure cerous oxalate. 
 
 If it be desired to obtain a basic nitrate of cerium free from sulphuric acid, as is often 
 desirable for other preparations, the red solution of the double nitrate must be evapo- 
 rated to a syrup, and then poured into a large excess of boiling water slightly acidu- 
 lated with nitric acid. The precipitate thereby formed is washed by decantation with 
 water containing a little nitric acid, and the mother-liquor, together with the wash- 
 water, is again evaporated to a syrup and treated as before, till nearly all the cerium 
 is extracted. The addition 'of nitric acid to the wash- water is essential, as the basic 
 nitrate dissolves somewhat readily in pure water. It is best to preserve the precipi- 
 tated salt under acidulated water, since it becomes insoluble in acids when dried and 
 ignited. (Bun sen, Ann. Ch. Pharm. cv. 40.) 
 
 Metallic cerium is obtained by heating the pure anhydrous protochloride with 
 potassium or sodium. It is a grey powder, which acquires the metallic lustre by pres- 
 sure. It oxidises readily, decomposes water slowly at ordinary temperatures, quickly 
 at the boiling heat, and dissolves rapidly in dilute acids, with evolution of hydrogen, 
 forming a solution of a cerous salt. 
 
 Cerium forms three classes of compounds, viz. tho cerous compounds, or proto-com- 
 pounds, e. g. the protochloride, CeCl, the protoxide Ce 2 ; the sesqui-compounds, or 
 eerie compounds, e.g. Ce 2 CP, andCe 4 3 , and the ceroso-ceric compounds, which may 
 be regarded as compounds of the other two ; e. g. ceroso-ceric oxide, Ce 3 2 = Ce 2 O.C 4 3 . 
 
 CERIUM, BROMIDE OP. Not known in the anhydrous state. A solution of 
 eerie oxide in hydrobromic acid yields by evaporation, small crystals of a hydrated 
 bromide, which gives off hydrobromic acid when heated and leaves an oxybromide. 
 
 CERIU1VC, CHIiORZDES OP. Cerium burns vividly when heated in chlorine 
 gas, and forms the protochloride CeCl. The anhydrous chloride may be prepared by 
 igniting the sulphide, or the residue obtained by evaporating to dry ness a solution of 
 the chloride mixed with sal-ammoniac, in a current of chlorine gas. If the air is not 
 completely excluded, an oxychloride is also produced. The anhydrous chloride is a 
 white porous mass, fusible at a red heat, and perfectly soluble in water. A hydrated 
 
CERIUM. 833 
 
 chloride is obtained in colourless four-sided prisms, by dissolving the hydrated oxide 
 or the carbonate in hydrochloric acid, and evaporating to a syrup. The solution when 
 exposed to the air, turns yellow, from formation of a ceroso-ceric salt. 
 
 Protochloride of cerium forms with Bichloride of 'platinum, an orange-coloured crys- 
 talline double salt, 2CeCl.PtCl 2 .4H 2 0, easily soluble in water and alcohol, insoluble. in 
 ether. It also combines with iodide of zinc. (Holzmann, Phil. Mag. [4] xxii. 219.) 
 
 Ceroso-ceric chloride. Hydrated ceroso-ceric oxide dissolves in cold hydrochloric 
 acid, forming a red solution, which, however, soon gives off chlorine, and is reduced, 
 more or less completely, to protochloride. 
 
 CERIUIVE, DETECTION AMTD ESTIP/EATIOW OP. 1. Reactions.^ 
 All compounds of cerium, ignited with borax or microcosmic salt in the outer blowpipo 
 flame, yield a glass which is deep red while hot, but becomes colourless on cooling. In 
 the inner flame, a colourless bead is formed with a small quantity of the cerium com- 
 pound ; but a yellow enamel with a larger quantity. 
 
 Cerous salts in solution are colourless, have a sweet astringent taste, and redden 
 litmus, even when the acid is perfectly saturated. They are distinguished by the fol- 
 lowing reactions : Sulphydric acid produces no precipitate. Sulphide of ammonium 
 throws down the hydrated protoxide. Caustic potash or soda produces a white preci- 
 pitate of the hydrated protoxide, which is insoluble in excess, and is converted into 
 the yellow hydrated sesquioxide by the action of chlorine-water or hypochlorous acid. 
 Ammonia precipitates a basic salt. Alkaline carbonates form a white precipitate of 
 cerous carbonate insoluble in excess. Oxalic acid or oxalate of ammonia produces a 
 white precipitate of cerous oxalate, gelatinous at first, but quickly assuming the crys- 
 talline character, and converted by ignition in an open vessel into a yellowish-white 
 powder consisting of ceroso-ceric oxide. Ferrocyanide of potassium produces a white 
 pulverulent precipitate ; ferricyanide of potassium none. Sulphate of potassium pro- 
 duces a white crystalline precipitate of potassio-cerous sulphate, nearly insoluble in 
 pure water, and quite insoluble in excess of sulphate of potassium. With dilute solutions 
 the precipitate takes some time to form. This character, together with the behaviour 
 of the oxalate and the yellow coloration of the hydrated protoxide by hypochlorous 
 acid, serves to distinguish cerium from all other metals. 
 
 2. Quantitative Estimation. Cerium is precipitated from neutral solutions of 
 oerous salts by carbonate of ammonium, as cerous carbonate, or by oxalate of ammonium 
 ae cerous oxalate ; and either of these compounds is converted by ignition in an open 
 vessel, into ceroso-ceric oxide, which, according to Bunsen, corresponds, within the 
 temtts of experimental error ; to the formula Ce s 2 , and contains 8T18 per cent, of 
 metallic cerium, or 95'04 per cent, of the protoxide. Another method is to dissolve 
 the precipitated carbonate in dilute sulphuric acid, evaporate, and heat the residue to 
 commencing redness, whereby it is converted into the anhydrous sulphate, Ce 2 S0 4 , 
 containing 48-95 per cent, of the metal, or 57'45 per cent, of the protoxide. 
 
 3. Separation from other Elements. Sulphydric acid serves to separate cerium 
 from all metals which are precipitated by that reagent from their acid solutions. From 
 manganese, iron, cobalt, nickel, zinc, titanium, chromium, vanadium, and tungsten, 
 cerium may be separated by means of a saturated solution of sulphate of potassium. 
 
 From aluminium it may be separated by carbonate of barium, which precipitates 
 alumina and not cerous oxide; from glucinum by sulphate of potassium. From 
 yttrium, with which it is often associated in minerals, it may be separated by a satu- 
 rated solution of sulphate of potassium, added in excess, the sulphate of yttrium and 
 potassium being soluble in excess of sulphate of potassium, while the cerous double 
 salt remains undissolved. From zirconium, cerium is separated by treating the boil- 
 ing acid solution with sulphate of potassium, whereby the greater part of the zirconia 
 is precipitated as basic sulphate, while the cerium remains dissolved ; to complete the 
 precipitation, a small quantity of ammonia must be added, but not sufficient to satu- 
 rate the acid (H. Eose). From magnesium also cerium may be separated by sulphate 
 of potassium ; from barium, strontium, and calcium, it is separated by ammonia added 
 in slight excess ; or from barium by sulphuric acid," and from strontium and calcium 
 by sulphuric acid and alcohol ; and from the alkali-metals by precipitation with oxalate 
 of ammonia. Bunsen' s method of precipitation already described, affords however the 
 the best means of separating cerium from all the metals with which it is found as- 
 sociated, especially from lanthanum, didymium, and yttrium. 
 
 4. Atomic Weight of Cerium. The older statements respecting the atomic 
 weight of this metal, all refer to cerium containing lanthanum and didymium. For this 
 impure metal, Hisinger, in 1814, found the number 45-65 (H -1), and Otto found 46-8. 
 After the method of removing the lanthanum and didymium had been pointed out by 
 Mosander, Beringer (Ann. Ch. Pharm. lii. 134), from the analysis of the proto- 
 
 VOL. I. 3 H 
 
834 CERIUM: FLUORIDES OXIDES. 
 
 chloride CeCl, deduced the number 47 '8, and from that of the sulphate the number 
 46-2. 
 
 Hermann, from an analysis of cerous sulphate, in which the sulphuric acid was pre- 
 cipitated as sulphate of barium, found for cerium the number 46. 
 
 Marignac (Ann. Ch. Pharm. Ixviii. 215), by precipitating cerous sulphate with a 
 graduated solution of chloride of barium, obtained, as a mean of seven experiments, 
 Ce = 47 P 26. Afterwards, however (Ann. Ch. Phys. [3] xxxviii. 148), he rejected this 
 number, and adopted that previously found by Hermann, viz. 46, attributing the excess 
 of his former determination to the circumstance, that a portion of the cerous sulphate 
 had been carried down undecomposed by the barium precipitate, whence the quantity 
 of chloride of barium required to precipitate the sulphate came out too low. 
 
 Lastly, Buns en has determined the atomic weight of cerium by the analysis of the 
 sulphate. Pure basic eerie sulphate, obtained as above described (p. 832), was dissolved 
 in sulphuric acid, reduced to cerous sulphate by sulphurous acid, the salt evaporated and 
 ignited till all the excess of acid was expelled, and the residue twice crystallised from 
 water. A solution of this salt was precipitated by oxalic acid ; the precipitated oxalate 
 converted into ceroso-ceric oxide by ignition in an open vessel ; and the sulphuric acid 
 precipitated from the filtrate by chloride of barium. The ceroso-ceric oxide was then 
 heated in a sealed flask containing very little air, with pure hydrochloric acid and 
 iodide of potassium, whereby it was reduced to cerous oxide, and a quantity of iodine 
 set free equivalent to the oxygen separated from the ceroso-ceric oxide. This free 
 iodine was estimated by Bunsen's volumetric method (ANALYSIS, VOLUMETRIC, p. 266), 
 
 and the corresponding amount of oxygen estimated by the formula x = ~=- a (ntf). 
 
 In this manner, 100 pts. of the ceroso-ceric oxide were found to contain 95-04 cerous 
 oxide and 4*96 oxygen. From this, the quantity of cerous oxide in the ignited ceroso- 
 ceric oxide (that is to say, in the original quantity of cerous sulphate), was calculated, 
 and the amount of sulphuric acid (SO 3 ) being likewise found from the precipitated sul- 
 phate of barium, the composition of the cerous sulphate was found to be 57*49 Ce 2 + 
 42-51 SO 3 = 100, whence the atomic weight of cerous oxide was found from the pro- 
 portion 42-51 : 57-49 = 80 : x, giving Ce 2 = 108-1, and therefore Ce = 46'1. Two 
 other experiments gave Ce = 46-02 and 46-05. 
 
 In accordance with the preceding results, the whole number 46 is generally adopted 
 as the true atomic weight of cerium. 
 
 CERIUM, FLUORIDES OP. The protofluoride CeF, is obtained as a white 
 precipitate, by adding an alkaline fluoride to a cerous salt. It is but partially reduced 
 by the action of hydrogen gas and potassium vapour at a red heat. (Mosander.) 
 
 The sesqui fluoride, Ce'-'F 3 , prepared in like manner, is a yellow precipitate. It also 
 occurs native as fluocerite, in brick-red or nearly yellow six-sided prisms and plates, 
 with very distinct basal cleavage ; also massive ; specific gravity 4*7. Hardness 4-5. 
 It gives off fluorine when strongly heated in a glass tube. It occurs at Finbo and 
 Broddbo, near Fahlun, in Sweden. Sesquifluoride of cerium also occurs with the 
 fluorides of calcium and yttrium, as yttrocerite (g. v.} 
 
 A Tiydrattd eerie oxyfluoride, Ce 8 F 6 3 + 3H 2 0, occurs at Finbo as fluocerine, in 
 yellow crystals with vitreous lustre, supposed to belong to the regular system (Gm. iii. 
 271). A mineral from Bastnas in Sweden, analysed by Hisinger, yielded numbers 
 corresponding to the formula Ce 8 F 6 3 + 4H 2 ; one from Finbo, analysed by Berzelius, 
 was found to consist of Ce 16 F 6 9 + 3H 2 0, or 2Ce 2 F 3 .3(Ce''0 3 .H 2 0). (Dana, ii. 96.) 
 
 CER.IUIVT, OXIDES OP. The Protoxide, or Cerous oxide, Ce 2 0, is obtained 
 by heating the carbonate or oxalate in a current of dry hydrogen perfectly free from air. 
 It is a greyish-blue powder, which on exposure to the air quickly becomes very hot, 
 and is converted into yellowish-white ceroso-ceric oxide. Cerous hydrate precipitated 
 from the solution of a cerous salt by a caustic alkali, is white, but when exposed to 
 the air, quickly changes to a yellow mixture of cerous carbonate and ceroso-ceric hy- 
 drate (Rammelsberg, Pogg. Ann. cviii. 40). The hydrate dissolves readily in 
 sulphuric, nitric, hydrochloric, and acetic acid, the solutions giving the characters 
 described at p. 833. 
 
 Ceroso-ceric Oxide, Ce 8 2 . This oxide, which may be regarded as a compound 
 of cerous and eerie oxide : 2Ce 8 2 = Ce 2 O.Ce 4 3 , is produced when cerous hydrate, car- 
 bonate, oxalate, or nitrate, is ignited in an open vessel. It is yellowish-white, acquires 
 a deep orange-red colour when heated, but recovers its original tint on cooling (Bun sen, 
 Ham me Is berg). Ignited in hydrogen gas, it assumes an olive-green colour, but 
 does not diminish perceptibly in weight (Bun sen). It is not raised to a higher state 
 of oxidation by heating in oxygen gas, or even by fusion with chlorate or hydrate of 
 potassium (E a mm e. Isberg). Nitric and hydrochloric acid have but little action upon 
 it, even at the boiling heat, unless it be mixed with the oxides of lanthanum and didy 
 
CERIUM : OXYGEN- SALTS SULPHIDES. 835 
 
 mium, in wliich case it dissolves readily in hot hydrochloric acid, with evolution of 
 chlorine. Heated with a mixture of iodide of potassium and hydrochloric acid, it 
 dissolves completely, with separation of iodine, a property which has been made 
 available by Bunsen for determining its composition. Strong sulphuric acid at the boil- 
 ing heat, converts it into an orange-red salt, which becomes light yellow on cooling, 
 and dissolves with yellow colour in water. 
 
 Marignac did not obtain ceroso-ceric oxide of constant composition, but supposed it 
 to have, for the most part, the composition 3Ce 2 0.2Ce 4 3 , or Ce M 9 . Eammelsberg, by 
 decomposing the ceroso-ceric sulphate, 3Ce 2 S0 4 .Ce 4 (S0 4 ) 3 with potash, obtained a 
 reddish-grey precipitate which contained 3Ce 2 O.Ce 4 3 , but was quickly converted into 
 Ce 3 2 , on exposure to the air. 
 
 Ceroso-ceric Hydrate, 2Ce 2 .3H 2 0, obtained bypassing chlorine into aqueous potash 
 in which cerous hydrate is suspended (p. 831), is a bright yellow precipitate, which dis- 
 solves readily in sulphuric and nitric acid, forming yellow solutions of ceroso-ceric 
 salts ; in hydrochloric acid, with evolution of chlorine, forming colourless cerous 
 chloride. 
 
 Ceric Oxide, Ce 4 3 , does not appear to exist in the free state, inasmuch as ceroso- 
 ceric oxide is not brought to a higher state of oxidation, even by ignition with power- 
 ful oxidising agents (vid. sup.) 
 
 CERXUltt, OXYGEN-SALTS OP. The cerous salts are produced by dissolv- 
 ing cerous oxide or carbonate in acids, also by the action of sulphurous acid and other 
 reducing agents on eerie or ceroso-ceric salts. (For their properties and reactions 
 see p. 833.) Cerous silicate exists in nature as Cerite ; the phosphate as Monazite, 
 Erdwardsite, Cryptolite, and Phosphocerite : the carbonate, together with fluoride of 
 calcium, in Parisite. 
 
 Cerous sulphate forms sparingly soluble double salts with the sulphates of ammo- 
 nium, potassium, and sodium. The potassium-salt, KCeSO 4 , is the least soluble in 
 water, and quite insoluble in solution of sulphate of potassium. 
 
 The ceroso-ceric salts are obtained by dissolving the corresponding oxide or hy- 
 drate in acids. The solution of the sulphate yields by spontaneous evaporation, first 
 brown-red crystals, composed of 3Ce 2 S0 4 .Ce 4 .(S0 4 ) 3 + 18 aq., and afterwards a yellow, 
 indistinctly crystalline salt, containing Ce 2 S0 4 .Ce 4 (SO') 3 + 8aq. By substituting 
 cericum, oe = 30 for cerosum, Ce = 46, in the sesquisulphate, these formulse may be 
 
 reduced to X ' \ + 6 aq. and ^ ' [ O 4 + 4 aq., respectively. Both salts are de- 
 
 f v^tJ.Oo y 
 
 composed by water, with separation of a basic salt, containing 5Ce 3 2 .3( p , [ O 4 ) 
 
 + 12aq., but dissolve on addition of sulphuric or nitric acid. The solution of either 
 salt yields, with sulphate of potassium, a mixture of at least two double salts, in which 
 potassium and cerosum may be regarded as replacing one another isomorphously : 
 similarly with sulphate of ammonium : the ammonium double salts, when ignited, leave 
 pure ceroso-ceric oxide. 
 
 The rhombohedral nitrate of cerium and magnesium obtained by Bunsen (p. 832), 
 is, when purified, a ceroso-cerico-magnesic salt, containing Mg 2 Ce(N0 3 ) 3 .(Ce 2 )'"(N0 3 ) 3 
 
 + 8aq., or -^ 2 Q e cc s ( O 8 + 8 aq. [As originally obtained, it contains lanthanum and 
 
 didymium, replacing cerium isomorphously.] Double salts of similar composition are 
 obtained by mixing a solution of this nitrate with the nitrates of potassium and zinc ; 
 
 with nitrate of nickel, a basic salt containing j^cP<L s ( 6 - NiHO + 12H2 - (Holz- 
 mann, J. pr. Chem. Ixxv. 321.) 
 
 The existence of pure eerie salts is by no means certain. Bunsen speaks of a basic 
 eerie sulphate, precipitated by boiling the solution of the magnesian ceroso-ceric salt 
 just mentioned, with sulphuric acid; but he has not given an analysis of it: indeed, 
 no analysis of a pure ccric salt has yet been published. The so-called basic eerie sul- 
 phate just mentioned, yields, by digestion with caustic potash, not eerie, but ceroso- 
 ceric hydrate (Holzmann). [For further details respecting the oxygen-salts of 
 cerium, see the several acids.] 
 
 CERIUM, PHOSPHIDE OP. Said to be obtained, together with phosphate, 
 by passing phosphoretted hydrogen over white-hot ceroso-ceric oxide. (Mosander.) 
 
 CERIUM, SELENIDE OP. Produced by decomposing cerous selenite with 
 hydrogen at a red heat. It is a brownish powder, which dissolves in acids, with evo- 
 lution of selenhydric acid. Cerous salts give with alkaline selenides a pale red preci- 
 pitate, probably consisting of hydrated selenide of cerium. 
 
 CERIUM, SULPHIDES OP. Cerous sulphide, Ce 2 S, is obtained by igniting the 
 earbonate in vapour of sulphide of carbon, or by heating an oxide of cerium with sul- 
 
 3 H 2 
 
836 CEROLEIN CEROTIC ACID. 
 
 phide of potassium. The first process yields a light powder of the colour of red lead ; 
 the second, a product resembling mosaic gold (Mosander). Ceric sulphide is not 
 known in the free state, but is said to combine with other metallic sulphides. 
 
 CEROXiEXN. A substance obtained from beeswax (in which it is said to exist 
 to the amount of 4 or 5 per cent.) by treating the wax with boiling alcohol, leaving the 
 cerotic acid to deposit on cooling, and evaporating the filtered solution. It is very 
 soft, melts a 28-5 C., dissolves readily in cold alcohol and ether ; is acid to litmus ; 
 gives by analysis 7874 per cent. C, 12-51 H, and 875 (Lewy, Ann. Ch. Phys. [3] 
 xiii. 438). It is probably a mixture. 
 
 CEHOLITE or KEROXiXTE (from /o/pos wax, and \i6os stone). This name is 
 applied to two or three minerals or mixtures, consisting chiefly of hydrated silicate of 
 magnesium more or less mixed with silicate of aluminium. They are all massive, 
 renifoim, compact or lamellar, transparent or translucent, white or grey, with vitreoiis 
 or resinous lustre, and greasy to the touch. 
 
 Analyses. a. From Frankenstein in Silesia by Kiihn ; b. from an unknown locality 
 by Delesse ; c. from Zoblitz in Saxony by Melling : 
 
 SiO 2 A1 4 3 Mg 2 Fe 2 H 2 
 
 a . . 46-96 31 26 21-22 = 99-44 
 
 b . . 53-5 0-9 28-6 16'4 = 99'4 
 
 c . . 47-13 2-57 36-13 2-92 11-50 = 100-25 
 
 The first agrees nearly with the formula Mg 4 Si0 4 + 3aq. (Eammelsbercf 's Mineral- 
 chemie, p. 862.) 
 
 CX4ROPXC ACID. An acid obtained by Kawalier (Ann. Ch. Pharm.lxxxviii.360) 
 from the needles of the Scotch fir (Pinus sylvestris). The needles are boiled with alcohol 
 of 40 percent., the alcohol is distilled off, and the residue is mixed with water, whereby 
 it is separated into a yellowish resin and a somewhat turbid liquid. The resinous 
 mass is redissolved in alcohol of 40 per cent., the solution precipitated with acetate of 
 lead, and the precipitate suspended in alcohol is decomposed by sulphuretted hydrogen. 
 The solution filtered hot deposits ceropic acid in yellowish- white flocks, which, by 
 boiling with alcohol and animal charcoal and repeated crystallisation from alcohol, 
 may be obtained in white, friable, microscopic crystals, melting at 100 C., and solidify- 
 ing in a waxy mass. The crystals dried in vacuo gave by analysis 74*24 per cent, 
 carbon and 12-17 hydrogen, whence Kawalier deduces the improbable formula 
 C^H^O 5 . The barium-salt gave 65-50 carbon, 10*33 hydrogen, 12'65 oxygen, and 
 11-52 baryta, represented by the formula BaO.C^H^O*. 
 
 CE:*OSXC ACID. C 48 H 96 3 . Obtained by heating cerosin (sugar-cane wax) 
 with potash-lime, and purified by saponifying with baryta, dissolving the soap in 
 alcohol, decomposing it with hydrochloric acid, and dissolving the precipitate in rock- 
 oil, whence it crystallises on cooling. It melts at 93C. ; dissolves sparingly in boiling 
 alcohol and ether. (Lewy, Ann. Ch. Phys. [3] xiii. 438.) 
 
 CEROSIN. Ccrosie. The wax of the sugar-cane, obtained by rasping the bark 
 of the cane, especially of the violet variety, and purified by recrystallising several 
 times from boiling alcohol. It then forms delicate white nacreous laminae, which do 
 not stain paper. Gives by analysis 8 TO to 817 C and 13-6 to 14-2 H, agreeing nearly 
 with the formula C 48 H 96 V , which represents it as a kind of aldehyde or ether. It 
 melts at 82 C., is insoluble in cold ether and alcohol, very soluble in boiling alcohol. 
 It is very hard and easily pulverised. (Avequin, Ann. Ch. Phys. Ixxv. 218; Dumas, 
 ibid. Ixxv. 222; Lewy, loc. cit.) 
 
 CEROTEVTE. C 27 H 54 . A hydrocarbon homologous with ethylene, first obtained 
 by Brodie (PhiL Mag. [3] xxxiii. 378 ; Ann. Ch. Pharm. Ixvii. 199) as a product of 
 the dry distillation of Chinese wax. The distillate consists of two parts, cerotic acid 
 passing over first, and afterwards cerotene mixed with a certain quantity of oily matter, 
 which may be removed by pressure. It is purified by crystallisation, first from a mix- 
 ture of alcohol and naphtha, then from ether. It is crystalline, melts between 67 
 and 58 C., and exhibits the characters of the substances which have been confounded 
 under the name of Paraffin (q. v.) When distilled several times, it is completely trans- 
 formed into a mixture of liquid hydrocarbons, whose boiling points vary from 75 to 
 260 C. 
 
 Chlorinated derivatives of Cerotene. When moist chlorine is passed over melted 
 cerotene, the latter assumes a waxy aspect, theft becomes gummy, and is ultimately 
 converted into a transparent resin, becoming harder as it absorbs more chlorine. The 
 reaction takes several weeks to complete, and at different stages of it the following 
 compounds are formed : C 27 H 36 C1 18 ; C 27 H 33 C1 21 ; CFIP-'Cl-' 2 . (Brodi e.) 
 
 CEROTIC ACID. C 27 H 54 O* = C^H^O.H.O. Crr in of Beeswax. (John, Ch?- 
 mische Schriftcn, iv. 38; Boudet and Boissenot, J. Pharm. xiii. 38; Ettling, Aim. 
 
CEROTIC ETHERS CERUMEN. 837 
 
 Ch. Pharm. ii. 267 ; Hess, ibid, xxvii. 3 ; Gerhardt, Eev. sclent, xix. 5 ; Lewy, Ann. 
 Ch. Phys. [3] xiii. 438; Brodie, Ann. Ch. Pharm. Ixvii. 180.) This acid is the essen- 
 tial constituent of that portion of beeswax which is soluble in boiling alcohol. It 
 is prepared by treating beeswax several times in succession with boiling alcohol, 
 till the deposit which forms on cooling melts at 70 or 72 C. The acid thus obtained 
 is not yet pure. It is, therefore, to be dissolved in a large quantity of boiling alcohol 
 and the solution precipitated by acetate of lead. The precipitate, after being ex- 
 hausted with the aid of heat by alcohol and ether, is decomposed by concentrated 
 acetic acid, and the product crystallised from alcohol yields pure cerotic acid. Cerotic 
 acid may also be obtained very nearly pure by crystallising several times from ether, 
 the crude product which melts at 72 C. The mother-liquors retain a small quantity 
 of another fatty acid. Cerotic acid is likewise produced by the dry distillation of 
 Chinese wax, and by melting that substance with potash. 
 
 Pure cerotic acid crystallises on cooling from its solutions in small grains, melting 
 at 78 C. The melted mass assumes on cooling a highly crystalline character. 
 
 The pure acid distils without alteration, but the impure acid is decomposed by dis- 
 tillation, yielding principally oily hydrocarbons of very variable boiling point, and 
 containing in solution small quantities of a fatty acid and other oxygenised products, 
 Chlorine transforms cerotic acid into chlorocerotic acid, C 27 H 42 C1 12 2 . 
 
 Cerotates. Cerotic acid is monobasic, the formula of its neutral salts being 
 C 27 H 53 M.0 2 . The lead-salt, C 27 H 53 Pb0 2 , is obtained as a white bulky precipitate on 
 mixing a solution of cerotic acid in boiling alcohol with alcoholic acetate of lead. The 
 silver-salt, C 27 H 53 Ag0 2 , is obtained by precipitating an alcoholic and ammoniacal solu- 
 tion of cerotic acid with nitrate of silver at the boiling heat. 
 
 CHLOROCEROTTC ACID. C 27 H 42 C1 I2 2 . Produced by exposing melted cerotic acid to 
 the action of chlorine for several days, 'as long indeed as fumes of hydrochloric acid 
 are perceptible. The product is a thick transparent gum of a pale yellow colour. 
 
 Chlorocerotate of sodium is nearly insoluble in water. 
 
 Chlorocerotate of ethyl, C 29 H 46 C1 12 2 =C 87 H 4I CP 2 0-.C 2 H 5 , is prepared similarly to the 
 cerotate. It has the aspect of chlorocerotic acid. 
 
 CEROTIC ETHERS. Cerotate of ethyl, C 29 H 58 2 = C 27 H 53 2 .C 2 H 5 , is 
 
 easily produced by passing hydrochloric acid gas into solution of cerotic acid in abso- 
 lute alcohol. It has the aspect of beeswax, and melts at 59 60 C. 
 
 Cerotate of Ceryl Chinese Wax. C 59 H 108 2 = g 0. This is a pecu- 
 
 liar waxy substance obtained from China, where it is produced on certain trees by 
 the puncture of a species of coccus. It is crystalline, and of a dazzling whiteness, like 
 spermaceti, but more brittle and of a more fibrous texture. It melts at 82 C. It is 
 purified by crystallisation from a mixture of alcohol and naphtha, then washed with 
 ether, treated with boiling water, and recrystallised from absolute alcohol, which dis- 
 solves it in small quantity only. Chinese wax is not saponified completely by boiling 
 with aqueous potash, but decomposes readily when fused with potash, yielding cero- 
 tate of potassium and hydrate of ceryl. By dry distillation it yields cerotic acid and 
 cerotene. Almost all the wax gathered in China is used there for making candles. It 
 is also employed by the Chinese as a medicine. 
 
 CEROTXXT. 8yn. of CERYLIO ALCOHOL or HYDRATE OF CERYL (p. 838). 
 
 CEROTXXTOXirE. The acetone of cerotic acid, obtained by careful distillation of 
 cerotate of lead. (Bruckner, J. pr. Chem. Ivii. 1.) 
 
 CEROXYIiXTT or Palm wax is the produce of the Ceroxylon Andicola, and is ob- 
 tained by rasping the epidermis of the tree and boiling the raspings in water. The 
 wax floats on the surface in a soft state, while the impurities sink to the bottom. It 
 may be further purified by repeated boiling with alcohol. In its natural state it is a 
 greyish-white powder ; after purification, yellowish-white. It is nearly insoluble in 
 alcohol, and melts at 72 C. It has been analysed by B oussingault (Ann. Ch. Phys. 
 xxix. 333), Lewy (Ann. Ch. Phys. [3] xiii. 458), and Teschemacher (Ann. Ch. 
 Pharm. Ix. 270) with the following results : 
 
 Boussingault. Lewy. Teschemacher. 
 
 Carbon .... 80'48 8073 80-28 
 
 Hydrogen . . . 13-29 13-30 13*20 
 
 Oxygen .... 6'23 5-97 6-42 
 
 100-00 100-00 100-00 
 
 CERUMEN OP THE EAR. A yellow secretion which lines the external audi- 
 tory canal, rendered viscid and concrete by exposure to air. It has a bitter taste, 
 
 3 H 3 
 
838 CERUSE CETIN. 
 
 molts at a low heat, and evolves a slightly aromatic odour. On ignited coals it 
 gives out a white smoke, similar to that of burning fat, swells, emits a fetid ammo- 
 niacal odour, and is converted into a light charcoal. Alcohol dissolves g of it, and on 
 evaporation leaves a substance resembling the resin of bile. The | which remain are 
 albumin mixed with oil, which by incineration leave carbonate of sodium and phos- 
 phate of calcium. U. 
 
 CERUSE or White lead. See CARBONATES (p. 786). 
 CERUSITE. Native carbonate of lead (p. 786). 
 
 CERVANTXTE. Native tetroxide of antimony, SbO 2 or Sb 2 3 .Sb 2 5 , found at 
 Cervantes in Spain and at Pereta in Tuscany (p. 324). 
 
 P27TI55 ) 
 
 CERlTXi, HYDRATE OP. Cerylic Alcohol, Cerotin. C 27 H M 0= V ^ I f-~ 
 
 Produced by fusing Chinese wax (cerotate of ceryl) with potash, digesting the fused 
 mass in boiling water, whereby a solution of cerotate of potassium is obtained holding 
 cerylic alcohol in suspension ; precipitating the cerotic acid with chloride of barium ; 
 and dissolving out the hydrate of ceryl with alcohol, ether, or coal-tar oil. The hy- 
 drate of ceryl, purified by several crystallisations from ether or alcohol, forms a waxy 
 substance melting at 97 C. Heated with potash-lime, it gives off hydrogen, and is 
 converted into cerotate of potassium : 
 
 C 27 H 56 + KHO = C 27 H 53 Z0 2 + 4H. 
 
 At a very high temperature it distils partly undecomposed, partly resolved into water 
 and cerotene, C 27 H 54 + H 2 0. Chlorine acts upon hydrate of ceryl, producing a trans- 
 parent pale-yellow substitution-product, chlorccrotal, containing 37'62 to 37'89 C, 
 476 to 4*78 H, and 55 - ll to 55-07 Cl, numbers which correspond to the formula 
 C 27 H 54 *C1 13 *0. The action of the chlorine was probably not complete. The product 
 has the appearance of a gum-resin, and becomes electrical by friction. (Brodie, Ann. 
 Ch. Pharm. Ixvii. 120.) 
 
 Hydrate of ceryl treated with excess of sulphuric yields a product which, when 
 washed with cold water, dried in vacuo, and crystallised from ether, has the composi- 
 tion of neutral sulphate of ceryl with 1 at. water, (C"H 55 ) 2 S0 4 + H 2 0. When pure it is 
 perfectly soluble in water, especially if a little alcohol is added ; the solution evaporated 
 at a low temperature leaves the substance in the form of a soft wax. (Brodie.) 
 
 CETEKTE or Cetylene, C 16 H 32 . (Dumas and Peligot, Ann. Ch. Phys. [2] Ixii. 4 ; 
 Smith, ibid. [3] vi. 40.) A hydrocarbon homologous with ethylene, obtained by dis- 
 tilling cetylic alcohol with phosphoric anhydride, also by distilling cetin (palmitate of 
 cetyl), and treating the product with potash to saponify the fatty acids which have passed 
 over in the distillation, the cetene then floating on the surface of the liquid. 
 
 Cetene is a colourless oily liquid, which stains paper. It boils at 275 C., distilling 
 without alteration. Vapour-density 8'007. It is insoluble in water, easily soluble in 
 alcohol and ether, neutral to test-paper. It has no particular taste. When set on fire r 
 it burns with a very pure white flame, like the fat oils. 
 
 Cetene unites with hydrobromic and hydrochloric acids, slowly at ordinary tempera- 
 tures, somewhat more quickly at 100 C. The compound is decomposed by distillation. 
 (Berthelot, Ann. Ch. Phys. [3] li. 81.) 
 
 The ethylosulphates (sulphovinates) yield by dry distillation an oily liquid (heavy 
 oil of wine), from which water separates an oily hydrocarbon (light oil of wine), which 
 boils at nearly the same temperature as cetene ; and this oil, when exposed to a very 
 low temperature deposits crystals (camphor or stcaroptene of wine-oil), having the same 
 composition. 
 
 CETZC ACID. C^H^O 2 ? Produced, according to Heintz, in very small quan- 
 tity in the saponification of spermaceti (p. 840). Crystallises in nacreous scales 
 grouped in stars, melting at 53'5 C. Benic acid obtained from oil of ben, and stillis- 
 tearic acid, from the fruit of Stillingia sebifera, have the same composition. 
 
 CETIN, C 32 H 64 2 . (Chevreul, Eecherches sur les Corps gras, p. 171; Smith, 
 Ann. Ch. Pharm. xlii. 247; Stenhouse, J. pr. Chem. xxvii. 253; Bad cliff, Ann. 
 Ch. Phys. [3] vi. 50.) A fatty crystalline substance constituting the essential part of 
 spermaceti, the substance which, in the state of solution in an oil, fills the cavities in 
 the head of the cacholot, or spermaceti whale, and other cetaceous animals. To obtain 
 it in a state of purity, spermaceti is treated with cold alcohol, which removes the oil, 
 and the residue is crystallised from boiling alcohol. 
 
 Cetin melts at 49 C., and solidifies on cooling in a translucent mass, which serves 
 for the manufacture of candles. Heated to 300, out of contact with the air, it vola- 
 tilises without alteration ; but if heated quickly and in considerable quantities, it is 
 completely decomposed into a solid fatty acid (palmitic acid), and a liquid hydrocarbon 
 
CETRARI A CETRARIC ACID. 839 
 
 (cetene), accompanied, chiefly towards the end of the distillation, by secondary pro- 
 ducts, such as water, carbonic anhydride, carbonic oxide, and olefiant gas. Cetin is 
 insoluble in water. 100 pts. of alcohol of '821 dissolve 2*5 pts. of it; absolute alcohol 
 and ether dissolve it in larger quantities, and deposit it on cooling in brilliant laminae. 
 Nitric acid attacks it slowly, and converts it into a mixture of cenanthylic, adipic, and 
 pimelic acids. 
 
 Cetin boiled with caustic alkalis is transformed into hydrate of cetyl and a palmi- 
 tute of the alkali-metal (Smith): 
 
 C 16 H 31 K0 2 . 
 
 Hydrate of Palmitate of 
 cetyl. potassium. 
 
 It must be observed, however, that the statements of different chemists regarding the 
 fatty acids resulting from the saponification of cetin do not quite agree. Chevreul" 
 obtained margaric and oleic acid. Heintz (Pogg. Ann. Ixxxiv. 232) obtained a mix- 
 ture of stearic, palmitic, myristic, cocinic. and cetic acids, which he separated by the 
 different solubility of the acids themselves, and of their barium-salts, in alcohol. He 
 therefore regards cetin, not as a simple proximate principle, but as a mixture of the 
 cetyl-salts of the acids just mentioned. By repeatedly crystallising spermaceti from 
 ether, he obtained at last a small quantity of a fatty substance, which melted at 
 53-5 C., but in other respects exhibited the characters of cetin, and also its composi- 
 tion, viz. 80-03 C, 13-25 H, and 672 0. 
 
 CETRARIA. See LICHENS. 
 
 CETRARIC ACID. Cetrarin. C I8 H 16 8 . (Berzelius, Schw. J. vii. 317; 
 Ann. Chim. xc. 277. Herberger, Ann. Ch. Pharm. xxi. 137. Knop and Schneder- 
 mann, ibid. Iv. 144.) Contained, together with lichenostearic acid, in Iceland moss 
 (Cetraria islandica}. To obtain the two acids, the lichen is treated for about a quarter 
 of an hour with a boiling mixture of strong alcohol and carbonate of potassium (15 grm. 
 of the carbonate to each kilogramme of alcohol), whereby the acids are dissolved 
 as potassium-salts. The filtered liquid mixed with hydrochloric acid, deposits the two 
 acids mixed with a green substance ; and by treating this mixture with 8 or 10 times 
 its weight of boiling dilute alcohol, the lichenostearic acid is dissolved, while the 
 cetraric acid and the green substance remain undissolved. 
 
 To isolate the cetraric acid, which forms the greater part of the residue, this residue 
 is washed several times with a mixture of ether and an essential oil, for the purpose 
 of removing the green matter ; it is then boiled with strong alcohol, which dissolves 
 the cetraric acid, and on cooling deposits it in slender needles, which are purified by 
 boiling them with animal charcoal, then dissolving them in potash, and decomposing 
 the potassium-salt with hydrochloric acid. (Knop and Schnedermann.) 
 
 Cetraric acid crystallises in extremely fine capillary needles, of dazzling whiteness. 
 It has a pure bitter taste, is nearly insoluble in water, sparingly soluble in ether, very 
 soluble in boiling alcohol. The crystals are anhydrous. 
 
 Cetraric acid turns brown when boiled with water ; the alcoholic solution also turns 
 brown on boiling: this change is much accelerated by the presence of an alkali. 
 Sulphuric acid colours cetraric acid, first yellow, afterwards red : the mass becomes 
 glutinous and dissolves : and water added to the solution throws down ulmic acid. 
 Hydrochloric acid dissolves a small quantity of cetraric acid, the undissolved portion 
 assuming a deep blue colour. This blue compound is dissolved with red colour by 
 strong sulphuric acid, and reprecipitated blue by water. This blue precipitate dissolves 
 in a mixture of dichloride and tetrachloride of tin, and alkalis added to the solution 
 throw down a blue lake (Herberger). Cetraric acid is oxidised by nitric acid, 
 yielding oxalic acid and a yellow resin. Chlorine and bromine do not appear to act 
 upon it. 
 
 Cetraric acid decomposes carbonates, and forms yellow salts, soluble in water and 
 alcohol, and having an intolerably bitter taste. It has a great tendency to form acid 
 salts. The neutral salts cannot be evaporated, even in vacuo, without decomposing 
 and turning brown. The acid salts are precipitated in a gelatinous form, by mixing 
 the neutral salts with half the quantity of hydrochloric acid necessary to saturate the 
 base. They are difficult to wash, but may be evaporated in the air without turning 
 brown. 
 
 An alcoholic solution of acid cetrarate of potassium, forms a deep red precipitate 
 iritih ferric chloride, the liquid at the same time assuming a blood-red colour. 
 
 Cctrarate of ammonium is obtained as a yellow powder, by treating the acid with 
 gaseous ammonia, of which it absorbs 10-2 per cent. The lead-salt, C 18 H 14 Pb 2 8 , is 
 obtained as a yellow flocculent precipitate, by mixing acetate of lead with cetrarate of 
 ammonium. The silver-suit is a yellow precipitate, which rapidly turns brown. 
 (Knop and Schnedermann.) 
 
 3 H 4 
 
840 
 
 CETYL : ACETATE CYANIDE. 
 
 CETYIi. C 16 H 33 . A monotomic alcohol-radicle not yet isolated, but supposed to 
 exist in a series of compounds homologous with the ethyl-compounds, and derived from 
 spermaceti. The cetyl-compounds at present known are : 
 
 Type H.H.O. 
 
 Hydrate of cetyl (cetylic alcohol) . . . C 16 H 33 .H.O 
 
 Oxide of cetyl (cetylic ether) .... (C 16 H 33 ) 2 
 
 Oxide of cetyl and sodium C 16 H 33 .Na.O 
 
 Oxide of cetyl and ethyl C I6 H 83 .C*H 5 .0 
 
 Oxide of cetyl and amyl C 16 H 38 .C 5 H n .O 
 
 Acetate of cetyl C 2 H 3 O.C 16 H 33 .0 
 
 Benzoate of cetyl C 7 H S O.C 16 H 3 '.O 
 
 Butyrate of cetyl C 4 H 7 O.C 16 H 33 .0 
 
 Stearate of cetyl C 18 H 35 .O.C la H 33 .0 
 
 Succinate of cetyl (C 4 H 4 2 )".(C' 6 H 33 ) 2 .0 2 
 
 Sulphate of cetyl and hydrogen . . . (S0 2 )".C 16 H 33 .H.0 2 
 
 Sulphydrate of cetyl . . . . . C 16 H 33 .H.S 
 
 Sulphide of cetyl (C 16 H 33 ) 2 S 
 
 rw*ri_f>,i Qrt ,'ri . ffinvniep 
 
 Cetyi-xanthic acid 
 
 Type HH. 
 Bromide of cetyl 
 
 Chloride of cetyl 
 Iodide of cetyl . 
 Cyanide of cetyl 
 
 ".C' 6 H 33 .H.S 2 
 
 C 16 H 88 Br 
 C I6 H 33 C1 
 C 16 H 33 I 
 
 Type NH 3 . 
 Nitride of cetyl, ortricetyl- 
 amine . 
 
 Cetylphenylamine 
 
 C i6 H 33 Cv 
 
 Dicetylphenylamine 
 
 (C 16 H 33 
 ; >C e H 5 
 ( H 
 (C 16 H 33 
 
 (C 6 H 5 
 
 CETYI,, ACETATE OP. C^H^O 2 = C 2 H 3 O.C 16 H 33 .0, is produced by treating 
 cetylic alcohol with acetic and hydrochloric or sulphuric acid, precipitating by water, 
 dissolving in ether, and evaporating, as an oily liquid, which at a low temperature soli- 
 difies, after awhile, in a mass of needle-shaped crystals, fusible at 18*5 C. (Becker, 
 Ann. Ch. Pharm. cii. 219.) 
 
 CETYI., BENTZOATE OF. C^H^O 2 = C 7 H 5 O.C la H 38 .0. Obtained by heating 
 chloride of benzoyl with cetylic alcohol in equivalent proportion, dissolving the residue 
 in ether, and precipitating with alcohol. It forms crystalline scales, which melt at 30 C., 
 dissolve readily in ether, and sparingly in alcohol. (Becker, loc. cit.) 
 
 CETYIi, BROMIDE OF. C 16 H 33 Br. Produced by the action of bromine and 
 phosphorus on cetylic alcohol. It is a colourless solid body, heavier than water in the 
 melted state, insoluble in water, very soluble in alcohol and ether; melts at 15C. 
 When distilled, it gives off hydrobromic acid. (Fridau, Ann. Ch. Pharm. Ixxxiii. 15.) 
 
 CETYIi, BUTYRATE OF. C 20 H 40 2 = C 4 H 7 O.C I6 H :)3 .0. Obtained by slowly 
 heating a mixture of cetylic alcohol and butyric acid to 200 C., and proceeding aa 
 with the benzoate. It is white, neutral, miscible with ether but not with alcohol, 
 melts more easily than cetylic alcohol, and when cautiously heated in small quantity, 
 volatilises without decomposition. (Handw. d. Chem. 2 te Aufl. ii. [2] 929.) 
 
 CETYL, CHLORIDE OF. C I6 H 33 C1. HydrocUorate of Cctene. Obtained by 
 the action of pentachloride of phosphorus on cetylic alcohol. The two bodies mixed 
 in fragments in a retort, become heated, melt, and act violently on each other, giving 
 off large quantities of hydrochloric acid. On subsequently distilling the product, 
 oxychloride of phosphorus passes over, and then chloride of cetyl, which may be 
 purified by redistillation with a small quantity of pentachloride of phosphorus, wash- 
 ing with boiling water, and drying in vacuo at about 120 C. If it still contains 
 hydrochloric acid, it must be distilled with lime recently ignited. (Dumas and 
 Peligot, Ann. Ch. Phys. Ixxii. 4.) 
 
 Chloride of cetyl is a limpid oily liquid of specific gravity 0'8412 at 12 C., insoluble 
 in water and in alcohol, but soluble in ether, whence it may be precipitated by weak 
 alcohol. It distils above 200 C., with partial decomposition, and by prolonged ebul- 
 lition the whole of the chlorine may be expelled as hydrochloric acid, leaving cetene 
 (p. 838). It is not acted upon by nitric acid, but strong sulphuric acid decomposes it, 
 eliminating hydrochloric acid and forming cetyl-sulphuric acid. It does not absorb 
 ammonia, (Tiitscheff, Rep. Chim. piire, ii. 463.) 
 
 CETYIi, CYANIDE OF. C 16 H 33 .CN. Obtained in an impure state, by heating 
 cetjlsnlphgte of potassium with cyanide of potassium, and extracting with ether 
 
CETYL: HYDRATE IODIDE. 841 
 
 (Kohler, Zeitschr. d. gesammt. Naturw. vii. 252 ; Jahresber. 1856, 579. Heintz, 
 Pogg. Ann. cii. 257 ; Jahresber. 1857, 445). According to Kohler, it is a solid crys- 
 talline substance, melting at 53 C., easily soluble in ether and in hot alcohol ; accord- 
 ing to Heintz, it is liquid at ordinary temperatures, but its formation is accompanied 
 by that of a crystalline solid, which melts at 55-1, and is probably a mixture of 
 cetylic ether with palmitic aldehyde. Heated with potash it appears to yield margaric 
 acid, C 17 H 34 2 . (Kohler.) 
 
 CETYI,, HYDRATE OP. C 16 H 34 = C 16 H 33 .H.O. Cetylic Alcohol, Ethal. 
 (Chevreul, Rechcrchcs sur les Corps gras, p. 171. Dumas and Peligot, Ann. Ch. 
 Phys. [2] Ixii. 4; Smith, ibid. [3] vi. 40 ; also, Ann. Ch. Pharm. xlii. 247. Heintz, 
 Pogg. Ann. Ixxxiv. 232 ; Ixxxvii. 553.) This compound is prepared by saponifying 
 spermaceti with an alkali, the cetiu, or palmitate of cetyl contained in that substance 
 being then resolved into an alkaline palmitate and hydrate of cetyl, which latter is 
 dissolved out by alcohol or ether. Dumas and Peligot add 1 pt. of solid hydrate of 
 potassium, by small portions and with constant agitation, to 2 pts. of melted sperma- 
 ceti, treat the resulting soapy mass with water, and then with a slight excess of hydro- 
 chloric acid. On boiling the liquid, the ethal and the fatty acids of the soap rise to 
 the surface, in the form of an oily layer, which is separated by decantation, and 
 saponified a second time in the same manner, to decompose a small remaining quantity 
 of spermaceti ; the fatty acids are again separated by means of hydrochloric acid, and 
 saponified with slaked lime added in excess. A mixture of lime-soap and hydrate of 
 cetyl is thus obtained, from which the latter is dissolved out by alcohol. Lastly, the 
 alcohol is distilled off, and the cetylic alcohol which remains is purified by crystallisa- 
 tion from ether. Heintz boils spermaceti with an alcoholic solution of potash ; preci- 
 pitates the boiling liquor with a concentrated aqueous solution of chloride of barium ; 
 and dissolves out the ethal from the precipitate with alcohol. As the alcohol also dis- 
 solves small quantities of barium-salts, it is removed by distillation, and the ethal 
 which remains is dissolved in cold ether, and finally purified by several crystallisations 
 from ether. 
 
 Cetylic alcohol or ethal is a white solid crystalline mass, which melts at a tempera- 
 ture above 48 C., but solidifies at 48 (Chevreul). It melts in water at 50 C., and 
 when it solidifies, the temperature rises to 51 -5 ; when melted alone, it solidifies at 
 49 or 49-5 (Heintz). When slowly cooled, it crystallises in shining laminae: it 
 also crystallises on cooling from solution in alcohol. It is without taste or smell, and 
 distils without alteration, passing over even with vapour of water. It is insoluble in 
 water, but mixes in all proportions with alcohol and ether. 
 
 Ethal does not give off water when heated with oxide of lead. It is not dissolved 
 by aqueous alkalis ; but when strongly heated with potash-lime, it gives off hydrogen, 
 and is converted into a potassium-salt, probably palmitate or ethalate (Dumas and 
 Stas, Ann. Ch. Phys. [2] Ixxiii. 124): 
 
 C 16 H 34 + KHO = C 16 H 31 K0 2 -f 4H. 
 
 Ethal is decomposed by sodium, yielding cctylate of sodium, C 16 H 3I KO. With potash 
 and sulphide of carbon it forms cetyl-xanthate of potassium, C 16 H 33 .K.COS 2 . Distilled 
 with pentachloride of phosphorus, it forms chloride of cetyl, oxychloride of phosphorus, 
 and hydrochloric acid : 
 
 C 16 H 33 .H.O + PC1 3 .C1 2 = C 16 H 33 C1 + PC1 3 + HCL 
 
 With iodine and phosphorus, it yields iodide of cetyL With strong sulphuric acid, it 
 forms cetyl-sulphuric acid, C 16 H 33 .H.SO ! . 
 
 Heintz (loc. cit.} regards ethal, not as a simple alcohol, but as a mixture of cetylic 
 and stearic alcohols, C 16 H 34 0, and C 18 H 38 : because, according to his experiments, 
 the ethalic acid of Dumas and Stas, is a mixture of palmitic and stearic acids, sepa- 
 rable by solution in boiling alcohol and precipitation by acetate of barium. 
 
 CETYI,, IODIDE OF, C 16 H 33 I. (Fridau, Ann. Ch. Pharm. Ixxxiii. 9). Pre- 
 pared by introducing phosphorus into cetylic alcohol heated to 120 C. in an oil-bath, 
 and adding an excess of iodine by small portions at a time, while the mixture is con- 
 tinually stirred. Hydriodic acid is then given off, together with phosphorous acid, while 
 iodide of phosphorus crystallises out, and iodide of cetyl remains in the liquid state. 
 When the reaction is complete, the iodide of cetyl is decanted, washed with cold 
 water, which causes it to solidify, and then crystallised from alcohol. It crystallises 
 in colourless interlaced laminae, insoluble in water, easily soluble in ether, more soluble 
 in boiling than in cold alcohol Melts at 22 C., and solidifies on cooling in rosettes 
 having a fatty aspect. Burns with a clear flame, giving off free iodine. 
 
 It does not distil without alteration, but decomposes quickly at 250 C., giving off 
 copious vapours of iodine and h} driodic acid, together with an oily hydrocarbon. It is 
 
842 CETYL: NITRIDE SULPHYDR ATE. 
 
 violently attacked by mercuric oxide at 200, yielding an oil (cetene ?) together with 
 iodide of mercury and metallic mercury, and leaving a crystallisable solid fusible at 50. 
 With oxide of silver recently precipitated, and still moist, it forms the same compound, 
 melting at 50. With cetylate of sodium it yields iodide of sodium and oxide of cetyl 
 C 16 H 33 .K.O + C I6 H 33 .I = KI + (C I6 H B ) 2 0. 
 
 Ammonia in solution does not act on iodide of cetyl, but gaseous ammonia converts 
 it into tricetylamine, N(C 16 H 33 ) 3 . With phenylamine it forms cetyl-phenylamine and 
 dicetyl-phenylamine. (Fridau). 
 
 CETYIi, NITRIDE OF. See CETYLAM3NB. 
 
 CETYL, OXIDE OF. Cetylic ether. (C 16 H 33 ) 2 0. Obtained by treating cetylate of 
 sodium, C 16 H 83 KO, with iodide of cetyl at 110 C., washing the product with boiling 
 water to remove iodide of potassium, and crystallising from alcohol or ether. It 
 crystallises in shining scales. Melts at 55 C., and solidifies between 63 and 54 in 
 a radiated mass ; distils at 300 for the most part without decomposition. It is not 
 attacked by hydrochloric or nitro-hydrochloric acid at the boiling heat, but strong sul- 
 phuric acid destroys it. (Fridau, Ann. Ch. Pharm. Ixxxiii. 20.) 
 
 Cetyl-ethyl-oxide or cetylate of ethyl, C 2 !! 5 .^ 6 !! 33 ^, and cetyl-amyl-oxide or cetylate 
 of ami/I, C 5 !! 11 .^ 6 !! 33 ^, are obtained in like manner by treating cetylate of sodium 
 with iodide of ethyl or amyl. They both crystallise in laminae, soluble in alcohol 
 or ether: the ethyl-compound melts at 20 C., the amyl-compound at 30. (Gr. Becker, 
 Ann. Ch. Pharm. cii. 220.) 
 
 Cetyl-sodium-oxide or cetylate of sodium, C 1B H 3 NaO, obtained by the action of 
 sodium or cetylic alcohol, is a greyish-yellow solid which begins to melt at 100 C. and 
 is perfectly fluid and transparent at 1 10. It is not decomposed by boiling water, but 
 hydrochloric acid separates cetylic alcohol from it,. (Fridau.) 
 
 CETYIi, STEARATE OF. C 34 H 68 2 = C 18 H M O.C 18 H 33 .0. Prepared like the 
 butyrate. Thin white shining laminae, sparingly soluble in boiling alcohol and in 
 cold ether, easily in boiling ether. Melts at 55 60 C., and forms a crystalline mass 
 on cooling. Volatilises with partial decomposition when heated in a tube. (Handw.) 
 
 CETYL, SUCCXWATE OF. C 36 H 70 4 = (C 4 H 4 2 )".(C I6 H 33 ) 8 .0 2 . Prepared by 
 heating 1 at. succinic acid with 2 at. cetylic alcohol in an air-bath, neutralising with 
 carbonate of sodium and recrystallising from ether. White laminae, sparingly soluble 
 in alcohol, more freely in ether- alcohol, still more in pure ether. (TiitschefF, 
 loc. cit.) 
 
 CETYi, SULPHATE (ACID) OP. Cetylsulphuric acid. Sulphocetic acid. 
 C 16 H 34 S0 4 = ^^g^-g-jo 2 . Produced by mixing sulphuric acid with cetylic alcohol 
 
 at the temperature of the water-bath (Dumas and Peligot, loc. cit.} According to 
 Kohler (loc. cit.) and Heintz (loc. cit.} the most abundant product is obtained by 
 mixing the two substances at the lowest temperature at which they will act, viz. at 
 the melting point of cetylic alcohol ; dissolving the mixture in alcohol and saturating 
 with potash ; separating the precipitate from the liquid ; concentrating the latter ; 
 treating the residue with ether, which extracts undecomposed cetylic alcohol, and 
 leaves cetylsulphate of potassium ; and repeatedly crystallising the latter from boiling 
 alcohol. 
 
 Cetylsulphate of potassium forms white nacreous laminae, consisting of interlaced 
 microscopic needles ; it is moderately soluble in hot alcohol, less in boiling water, in- 
 soluble in ether. It is not fusible. Heated to 140 C. with cyanide of potassium, it 
 yields cyanide of cetyl. 
 
 CETYL, SULPHIDE OF. (C 16 H 33 ) 2 S. Prepared by the action of chloride 
 of cetyl on an alcoholic solution of monosulphide of potassium at the boiling heat. 
 Chloride of potassium then forms and sulphide of cetyl rises to the surface of the 
 liquid, where it solidifies on cooling. It is then washed with cold water, melted in 
 boiling water, and repeatedly crystallised from a mixture of alcohol and ether, till the 
 melting point becomes fixed at 5 7 '5 C. It forms shining scales resembling those of 
 cetylic mercaptan. It dissolves readily in ether, and in boiling alcohol, very sparingly 
 in cold alcohol. The alcoholic solution forms a white precipitate with acetate of 
 lead, also dissolved in alcohol. (Fridau, Ann. Ch. Pharm. Ixxxiii. 16.) 
 
 CETYL, SULPHYDRATE OF. Cetylic Mercaptan. C 18 H 33 .H.S. Prepared 
 by treating sulphydrate of potassium dissolved in alcohol with an alcoholic solution of 
 chloride of cetyl. The product contains a certain quantity of sulphide of cetyl. _ It is 
 purified by adding acetate of lead, then water, washing with water, and digesting in 
 ether, which dissolves the cetylic mercaptan and deposits it on evaporation in crystal- 
 line scales having a silvery lustre. It melts at 50'5C., but solidifies again only when 
 cooled down below 44, assuming the form of interlaced dendrites. It is sparingly 
 
CETYLAMINES CHABASITE. 843 
 
 soluble in cold alcohol, easily in ether, somewhat less easily in boiling alcohol. When 
 boiled with water it gives off a peculiar odour. 
 
 The cold alcoholic solution produces, after a while, white flocculent precipitates with 
 the alcoholic solutions of silver-salts and of mercuric chloride ; it does not precipitate 
 the salts of lead, platinum or gold. Mercuric oxide does not act sensibly upon it, 
 even at high temperatures. (Fridau, Ann. Ch. Pharm. Ixxxiii. 18.) 
 
 CETYXiAIVKXNES. Bases formed by the substitution of one or more atoms of 
 cetyl in place of hydrogen in a molecule of ammonia. Mono- and di-cctylamine are 
 not known. 
 
 Tricetylamine or Nitride of Cetyl. C 48 H"N=N(C I6 H 33 ) 8 . This base is produced 
 by passing ammonia-gas into iodide of cetyl heated to 150 C. A white precipitate 
 of iodide of ammonium is then formed, increasing in quantity if the temperature be 
 maintained for a while at 180, and the substance which remains in the fused state is 
 tricetylamine. It dissolves in boiling alcohol and crystallises in colourless needles, 
 melts at 39 C. and solidifies in mammellated crystals on cooling. 
 
 The salts of tricetylamine are insoluble in water, but soluble in ether and alcohol, 
 especially in the hot liquids. The hi/drochlorate, C 48 H 99 N.HC1, crystallises from boiling 
 alcohol in needles, which are less fusible but more soluble than the base itself. Potash 
 added to the boiling solution separates tricetylamine in the form of a heavy oil. 
 The chloroplatinate, C 48 H"N.HCl.PtCl 2 , is a cream-coloured, almost pulverulent pre- 
 cipitate, insoluble in water, sparingly soluble in alcohol. (Fridau, Ann. Ch. Pharm. 
 Ixxxiii. 25.) 
 
 Cetylphcnylamine, N.H.C I6 H 33 .C 6 H 5 , and Dicetylphenylamine, N.(C 16 H 33 ) 2 .C 6 H 5 , are 
 produced by the action of iodide of cetyl on pheny famine (q. v.) 
 
 CETYX.-XANTHIC ACID. C 17 H 34 OS 2 = c ^] H |s 2 . This acid is known only 
 
 as a potassium-salt, which is prepared by adding alcohol and hydrate of potassium to 
 a saturated solution of cetylic alcohol in sulphide of carbon, heating the mixture a 
 little below the boiling point of alcohol, then leaving it to itself for a while and 
 decanting. The clear solution, on cooling, deposits light scales, which may be purified 
 by washing with a small quantity of cold alcohol and dissolving in boiling alcohol. 
 
 The salt is white, tasteless, odourless, very hygroscopic and unstable. Its alcoholic 
 solution gives a white precipitate with mercuric chloride ; canary-yellow with nitrate 
 of silver, blackening in a few minutes ; white with acetate of lead, also blackening 
 rapidly ; white gelatinous with salts of zinc. Digested with hydrochloric acid, it yields 
 cetylic alcohol. (Desains and De La Provostaye, Ann. Ch. Phys. [3] vi. 494.) 
 
 CEVADIC ACID. An acid existing in the seed of sabadilla ( Veratrum Saba- 
 dilla, Kitz), and probably also in the root of white hellebore ( Veratrum album), and 
 of Colchicum autumnale. To prepare it, the oil extracted from sabadilla seeds by 
 ether is saponified with potash; the soap decomposed by tartaric acid; the mixture 
 distilled ; the distillate neutralised with baryta ; and the resulting barium-salt eva- 
 porated to dryness, and distilled with syrupy phosphoric acid. Cevadic acid then 
 sublimes in white nacreous needles. It is soluble in water, alchohol, and ether, and 
 smells like butyric acid ; melts at 20 C. and sublimes at a temperature a few degrees 
 higher. Its salts have a peculiar odour. The ammonium-salt gives a white precipitate 
 with ferric salts. 
 
 CEVADXXT or IXORDEXXT. A mixture of starch, cellulose, and azotised matter 
 obtained from barley. 
 
 CEYXiAWITE or CEYXiORTXTE. A ferruginous variety of spinel (Al 2 Mg0 2 ), 
 from Ceylon, and other localities, having the magnesium more or less replaced by 
 ferrosum, and the aluminium by ferricum. It is the plconast of Haiiy. (See SPINKL.) 
 
 CHABASITE. A mineral belonging to the zeolite family, and consisting es- 
 sentially of hyclrated silicate of aluminium and calcium, a certain portion of the 
 calcium being however always replaced by potassium or sodium. It crystallises in 
 forms belonging to the hexagonal system. Primary form, an obtuse rhombohedron, 
 having the angle of the terminal edges = 94 46'. It occurs in the primary form, and 
 in the combination R. |R. 2R. Ratio of principal to secondary axes = 1-086. 
 Cleavage distinct parallel to R. Specific gravity 2-0 to 2-1. Hardness 44-5. Trans- 
 parent and colourless, sometimes flesh-red, with vitreous lustre. Streak uncoloured. 
 Fracture uneven. Brittle. Shrinks before the blowpipe to a blistered, slightly trans- 
 lucent enamel. It is perfectly decomposed when heated in the state of powder before 
 the blowpipe. It occurs in scattered crystals in the fissures of some trap rocks, and 
 in the hollows of certain geodes disseminated in the same rocks. 
 
 The composition of most varieties of chabasite is nearly represented by the formula 
 Ca 2 O.Al 4 O 3 .4Si0 2 + 6aq., which (if=f Al), may be reduced to that of a meta- 
 eilicate (Ca a^ 3 )Si 2 6 + 3aq. Sometimes, however, the amount of alkali is consider- 
 
844 CH^EROPHYLLUM CH ALCOPH ACITE. 
 
 able, as in the fourth of the following examples, which approaches nearly to 
 3aq. 
 
 Analysis a is of a specimen from Kilmalcolm in Renfrewshire, by Thomson ; b, from 
 Aussig in Bohemia, by Eammelsberg ; c, from Annerode near Giessen, by Genth ; 
 d, from Port Rush in Ireland, by Thomson : 
 
 SiO* AHQ3 Fe"Q3 Ca2Q Na2Q R2Q H2Q 
 
 a . . 4875 17-44 10-47 1'45 2172 = 99-93 
 
 b . . 47-91 18-14 9-64 0-25 2-56 21-50 = 100*00 
 
 c . . 47-00 1971 0-15 10-63 0-65 0-33 22-29 = 100-76 
 
 d . . 48-99 19-77 0'40 4-07 6-07 2070 = 100-00 
 
 Sometimes, however, the proportion of silica is somewhat greater, and the com- 
 position is more nearly represented by the formula 2(Ca 2 O.Al 4 3 ).5Si0 2 + 12aq. or 
 (Ca 4 oZ 18 H 2 )Si 9 27 + llaq. ; and here again, the proportion of alkali-metal may be con- 
 siderable, as in the variety called acadiolite, which may be represented by the formula 
 
 (Ca^Na^K5) 4 a^ 2 H*Si 9 27 +llaq. Analysis e is chabasite from Drottning Grufva 
 near Gustassberg in Jemtland (Berzelius); / is acadiolite, from New Caledonia 
 (Hayes): 
 
 Si O2 A1<Q3 Ca2Q Na2Q R2Q H*O 
 
 e . . 60-65 17-90 9-37 170 19-90 = 99-52 
 / . . 52-02 17-88 4-24 4-07 3-03 18-30 = 99-54 
 
 (Rammelsberg's Mineralchemie, p. 816.) 
 
 According to Dana, Haydenite from Jones' Falls in Maryland, is merely a ferruginous 
 Variety of chabasite crystallised in scalenohedrons. Phacolite from Leipa in Bohemia is 
 another mineral of similar constitution, but containing less water, viz. (M l aPH 2 )Si 9 0'" 7 
 + 9aq. 
 
 CH-EEROPHYXiIiTJlVT. The fleshy root of Chceropkyllum bulbosum, which is now 
 coming into use in France as an article of food, has been examined by Pa yen (Compt 
 rend, xliii. 269), and compared with that of the potato (a yellow variety) : 
 
 Chaerophyllum Potato. 
 
 Water 63-618 
 
 Starch, &o 28-634 
 
 Cane-sugar 1-200 
 
 Albumen and other nitrogenous substances . 2-600 
 
 Fat 0-348 
 
 Inorganic matters 1-500 
 
 Cellulose and pectin-substances . . . 2'100 
 
 74-00 
 21-20 
 
 1-50 
 0-10 
 1-56 
 1-64 
 
 The comparison is evidently to the advantage of the chserophyllum. According to 
 Polstorf (N. Arch. Pharm. v. Brandes, xviii. 176), the seeds of this plant contain 
 an alkaloid, chcerophylline. Most species of chserophyllum are aromatic. 
 
 CHAIX.X.ETX.A. TOXIC ARIA. An ulmaceous plant possessing poisonous seeds. 
 
 CH ALC ANTHITE. Native sulphate of copper. (See SULPHATES.) 
 
 CHALCEDONY or Calcedony. A variety of quartz exhibiting various shades of 
 white, yellow, grey, brown, green, and blue. It has usually the subdued lustre of wax, 
 and is transparent or translucent, some milk-white varieties being opaque. It occurs in 
 mammillary and botryoidal shapes, and as stalactites in cavities roofed or lined with it. 
 According to Fuchs, it is true quartz with some opal disseminated through it. Va- 
 rieties of chalcedony are: agate, carnelian, cat's eye, chrysoprase, flint, hornstone, 
 onyx, plasma, and sand (q. v.) Common chalcedony occurs in the toadstone of Derby- 
 shire, in the trap rocks of Fifeshire, the Pentland Hills, and the Hebrides ; magnificent 
 specimens also in Trevascus Mine in Cornwall, in Iceland, and in the Faroe Isles. 
 
 CHALCODITE. A hydrated magnesio-ferrous silicate found near Antwerp in 
 Jefferson county, New York, and originally mistaken for cacoxene. It occurs in 
 stellate globular masses, having a bronze-like aspect, or as a deposit upon red haema- 
 tite ; also in prisms with very distinct cleavage in one direction. Translucent, 
 yellowish-brown to blackish-green, with somewhat lighter streak. Lustre metalloidal ; 
 on the cleavage faces, metallic and nacreous. Very flexible in thin laminae. Hardness 
 1 to 1*5. Before the blowpipe, it gives off water, and exhibits the reactions of iron. 
 Hydrochloric acid does not act upon it in the cold, but when heated, decomposes it 
 with separation of silica. (C. U. Shepard, Sill. Am. J. [2] xiv. 265.) 
 
 CHAI.COI.ITE. See UBANITE. 
 
 CHAI.COPHACITE. Octahedral arsenate of copper. (See LIROCONITE.) 
 
CHALCOPHYLLITE - CHAMPAGNE WINE. 845 
 
 CHAIiCOPHlTXiIiXTE. Syn. with COPPEE-MTCA. 
 CHAIiCOPYRITE. Syn. with COPPER-PYRITES. 
 
 CHAXiCOSTXBXTE. Native sulphautimonite of copper. (See WOLFSBERGITE.) 
 CHALCOTRICHITE. Native cuprous oxide. (See COPPER, OXIDES OF.) 
 CHAXiXXiXTE. This name is applied to two minerals found imbedded in grey 
 almond-stone, from the county of Antrim in Ireland. One of these minerals ia 
 amorphous, with conchoidal fracture ; cream-coloured, with faint waxy lustre ; trans- 
 lucent on the edges, with faint lustre on the streak ; slightly xinctuous to the touch, 
 and adhering to the tongue. In water, it falls to pieces with decrepitating noise. It 
 is decomposed by hydrochloric acid, with separation of pulverulent silica. 
 According to v. Ilauer ("Wien Acad. Ber. xii. 229) it contains 
 
 SiQ2 AHQ3 Fe'^0 Ca2Q Mg2Q IFO Total. 
 
 44-11 10-90 1-05 674 13-01 24-07 = 99'88 
 
 with traces of manganese and potassium, whence the formula: 4M 2 O.Al 4 3 .6SiO* + 
 13H-'0. 
 
 The other mineral (first analysed by Thomson), is a dense aggregate of concen- 
 trically fibrous spherules, of pale blood-red colour ; glistening ; translucent on the edges ; 
 of hardness 5, and specific gravity 2*24. It does not fall to pieces in water, and when 
 decomposed by hydrochloric acid, yields a jelly of silica. 
 
 This mineral, analysed by v. Hauer (Wien Acad. Ber. xi. 18) gave: 
 
 Loss by 
 
 SiQ2 A14Q3 FdCS Ca2Q Mg*O ignition. Total. 
 
 38-26 2771 trace 12-01 6'85 14-32 = 99-15 
 
 whence the formula 6M 2 0.4Al 4 3 .9Si0 2 + 12H 2 (Kenngott, Jahresber d. Chem. 
 vi. 826 ; vii. 842). Both minerals are orthosilicates, the formula of the first being 
 reducible to (M 8 tf/ 6 H IO )Si 6 24 + 7aq. which is of the form 6R 4 Si0 4 + 7aq., and that of 
 the second to (M 4 ^ 8 )Si 3 12 + 4aq. or 3R 4 Si0 4 + 4aq. 
 
 CHAXiK. Friable carbonate of calcium, very abundant, and forming the uppei 
 member of the cretaceous group which occupies nearly the whole of the south-eastern 
 part of England, and a considerable portion of the north of France. It is white and 
 opaque, very soft, and without the least appearance of polish in its fracture. Specific 
 gravity 2'4 to 2'6. It contains about 2 per cent, of clay, besides free silica. Some 
 specimens, perhaps most, contain a little iron. Sometimes also magnesia and chloride 
 of calcium occur in small quantities. It may be purified by trituration and elutria- 
 tion, the ferruginous and siliceous particles subsiding first, while the pure chalk 
 particles remain suspended : this purified chalk when dried is called whiting. Chalk 
 is extensively used in agriculture, as an addition to soils which are deficient in 
 lime. 
 
 The name chalk is also occasionally applied to other earthy minerals ; thus Black 
 chalk is a peculiar kind of slate, also called Drawing slate, which produces a black 
 shining streak on paper, and is used in crayon drawing. Red chalk is a clay, coloured 
 by oxide of iron. 
 
 CH AIiK STONES. Gouty concretions in the joints, so called from their resem- 
 blance to chalk. They consist mainly of uric acid. 
 
 CHAX.KOSXNE. Syn. with COPPER-GLANCE. 
 
 CHALYBEATE WATERS. Mineral waters containing carbonate of iron dis- 
 solved in excess of carbonic acid (p. 785). 
 
 CHAIiYBITE. Native carbonate of iron (p. 784). 
 
 CHAJViJEXiEOOT iviXNERAXi. Manganate of potassium. (See MANGANATES.) 
 
 CHAXKJEROPS HUMXI.XS. The leaves of this palm are coated with wax, 
 separable by alcohol into cerin and myricin. (Teschemacher, Ttochleder's Phytochemie 
 p. 219.) 
 
 CHAXttOISXTE. A black earthy mineral from Chamoisin in the Valais, contain- 
 ing, according to Berthier (Ann. Min. v. 393), 14-3 per cent, silica, 60'5 ferrous 
 oxide, 7'8 alumina, and 17'4 water ( = 100), with 15 per cent, of carbonate of calcium. 
 It is perhaps a mixture of magnetic iron ore with a hydrated silicate of aluminium. 
 
 CHA1V1OTTE. A mixture of fire-clay and fragments of burnt pottery used for 
 making fire-bricks, pipes, crucibles, &c. Chamottc-stones from the kaolin of Halle, 
 were found by Wackenroder (Arch. Pharm. [2] Ixxv. 27), to contain 85*00 per cent, 
 silica, 11-33 alumina, 2-23 ferric oxide, and a trace of magnesia; loss by ignition 1-00. 
 
 CHAMPAGNE WINE is made from selected grapes, red and white, the must 
 of which, after fermenting in the vats from 12 to 15 hours, is drawn clear off into the 
 casks ; it is racked off about Christmas, once more after four weeks, and then fined with 
 
846 
 
 CHANTONITE - CHEESE. 
 
 isinglass, which treatment is also repeated. The new wine is put into stout bottles in 
 the month of May, leaving about 2 inches empty under the corks, which are wired 
 down ; and the bottles are laid on their sides for the progress of the fermentation : 
 from 6 to 10 per cent, of the bottles burst. This stage of the process is completed 
 in September, when the bottles are placed on their mouths, and left so for fourteen days 
 to let the sediment settle in the neck, which settlement is promoted by a slight shak 
 
 ing. 
 
 By dexterous opening of the bottles, the muddy deposit is discharged, and thej 
 are then filled up with clear wine, corked afresh, and packed up for transport, the cork 
 being covered either with melted resin, wax. or tin-foil. In seasons or districts 
 when the must is not sweet enough, sugar is added by pouring a thimble-full of syrup 
 (called liquor), into each bottle, the wine destined for Russia receiving a double 
 dose. 
 
 A like procedure is followed in making the sparkling wines of Germany, as on the 
 Moselle, and at Esslingen in "Wurtemburg. Carbonic acid gas is frequently condensed 
 by an air-pump into the other more or less factitious frothing wines of France and 
 Germany. U. 
 
 CHANTO10TTE. A mineral said to exist in certain meteorites (<?.#.) 
 
 CHARA FG3TIDA. The ash of this plant has been analysed by Schulz-Fleeth 
 (Pogg. Ann. Ixxxiv. 80). Two specimens of the dried plant yielded 54-58 and 68-39 
 per cent, of ash, the chief characteristic of which was the very large quantity of lime 
 which it contained, viz. 427 per cent., which exists in it almost entirely in the form of 
 carbonate. The water in which the plant grew yielded in 100 pts. 0'1618 pt. of solid 
 matter, of which 0-104 consisted of carbonate of calcium. 
 
 CHARCOAI.. See CARBON (p. 759) ; also Ure's Dictionary of Arts, Manufac- 
 tures and Mines, i. 615). 
 
 CHATHAXKXTE. Native arsenide of cobalt. (See COBALT.) 
 
 CHAVXCA OFFXCXNARUXUE. One of the names of the plant which yields 
 long pepper. (See PEPPER.) 
 
 CHAT or CHAYA ROOT. The root of the Oldcnlandia umbellata, which grows 
 wild on the coast of Coromandel, and is likewise cultivated there for the use of dyers 
 and calico-printers. It is used for the same purposes as madder, to which it is said 
 to be far superior, giving the beautiful red so much admired in the Madras cottons. U. 
 
 CHEESE is formed from milk by coagulating it with rennet ; separating the curd 
 from the whey ; compressing the curd in moulds, after it is duly seasoned with salt ; 
 and keeping this solidified milk in a cool place for some time, to allow it to undergo 
 a kind of fermentation, by which it acquires the flavour and other well known pro- 
 perties of cheese. The chemical changes undergone by the casein in this process 
 are little understood. The milk, before it is coagulated, should be heated to about 
 85 F. ; then it receives the rennet the infusion in water of the stomach of a new- 
 born calf, commonly salted and dried to make it keep. The rennet effects its curdling 
 completely in about an hour and a half. The curd is cut with a three-bladed knife ; 
 drained of its whey ; broken down by hand or otherwise, subjected to compression ; 
 then comminuted more completely; put into its mould; and exposed to a graduated 
 pressure, commonly under a heavy weight, but in large dairies by a screw press, which 
 can be progressively tightened. The comminuted curd may be well salted by en- 
 closing it in linen cloth and immersing it for one day or several days in brine. It is 
 then drained, wiped, and set away in a cold room. Roquefort cheese is made from a 
 mixture of sheep and goats' milk, and is ripened in a chamber or cellar having a 
 very low temperature. U. 
 
 The following table exhibits the composition of several kinds of cheese, as deter- 
 mined by Payen (J. Pharm. [3] xvi. 279). 
 
 Composition of Cheese. 
 
 
 Water 
 in 
 
 Ash 
 
 in lOt) pts. of 
 substance : 
 
 Nitrogen 
 in 100 pts. of substance: 
 
 Fat 
 in 100 pts. of 
 substance. 
 
 
 100 pts. 
 
 ^ i 
 
 JL ^ 
 
 
 
 
 normal. 
 
 dry. 
 
 normal. 
 
 dry. 
 
 ash- free 
 
 normal. 
 
 dry. 
 
 Cheese from Chester 
 
 30-39 
 
 4'78 
 
 6-88 
 
 556 
 
 8-00 
 
 8-59 
 
 25-41 
 
 3G-61 
 
 Brie . 
 
 53-99 
 
 5-63 
 
 12-08 
 
 2-39 
 
 5-14 
 
 5-85 
 
 24-83 
 
 3329 
 
 Neufchatel 
 
 61-87 
 
 4-25 
 
 11-17 
 
 2"2S 
 
 5-99 
 
 fi'07 
 
 18-74 
 
 4!C15 
 
 Marolles 
 
 40-07 
 
 5-93 
 
 9-91 
 
 373 
 
 9 24 
 
 6-92 
 
 2ft- 73 
 
 47-9S 
 
 Roquefort 
 
 26-53 
 
 4-45 
 
 6-06 
 
 507 
 
 6-91 
 
 7-35 
 
 32-31 
 
 4399 
 
 Holland 
 
 41-41 
 
 6-21 
 
 10-61 
 
 4-10 
 
 7-01 
 
 7-84 
 
 25-06 
 
 427* 
 
 Gruydres 
 
 32-05 
 
 4-79 
 
 7 05 
 
 5-40 
 
 796 
 
 8-59 
 
 2H-40 
 
 41-81 
 
 Parmesano 
 
 30-31 
 
 7-09 
 
 roi& 
 
 5-48 
 
 787 
 
 876 
 
 21 68 
 
 31M2 
 
CHEIRANTHUS CHEIRI CHELIDONTC ACID. 847 
 
 The ash of two samples of cheese has been analysed by Johnson (Ann. Ch. Pharm. 
 Ixxviii. 119): a. Hand-cheese (Hand-Kasc) from the neighbourhood of Giessen, 
 b. Swiss cheese. 
 
 K 2 O Na 2 Ca 2 Mg 2 FVO 3 CO 2 P 2 5 NaCl 
 
 4-85 7-33 2-55 0-11 0'03 13-68 72'47 = 101-02 
 
 2-46 3-67 17-82 0'81 0-17 0'08 20-45 55-37 = 100-83 
 
 The hand-cheese exhibited an alkaline reaction; gave off 46-35 per cent, water at 
 100 C. ; the dried substance yielded 12-86 per cent, nitrogen and 13-15 per cent. ash. 
 The Swiss cheese yielded 4470 percent, water, azid, after drying, 8'0 per cent, nitrogen 
 and 11*36 per cent. ash. 
 
 On the preparation of cheese, see Traite de -Chimte generate, par Pelouze et Fremy, 
 2 me ed. vi. 213, and Muspratfs Chemistry, article CHEESE. 
 
 CHEI2SAWTKUS CHEIRI. Wallflower. The fragrant flowers of this plant 
 have a bitter taste like that of cress. They contain a substance which assumes a 
 carmine colour in contact with sulphuric acid. The seeds contain myrosin, but no 
 myronic acid. (Rochleder 's Phytochemie, p. 98.) 
 
 CHEIiERYTHRITCTE. An alkaloid existing in very small quantity in Chelido- 
 nium majus (Probst, Ann. Ch. Pharm. xxix. 120 ; xxxi. 250). It forms orange-red 
 salts, and, according to Schiel (Sill. Am. J. [2] xx. 220), is identical with sangui- 
 narine, C 19 H 1C 4 , the alkaloid of Sanguinaria canadensis. (See SANGUINARINE.) 
 
 CHBX.ZBOZO-ZC ACIB. C 7 H 4 6 = 3 O 3 . (Probst. Ann. Ch. Pharm. xxix. 
 
 116. Lerch, ibid. Ivii. 273. Hutstein, N. Br. Arch. Ixv. 23. Gm. xiv. 413. 
 Gerh. iii. 754). This acid exists in all parts of Chelidonium majus, the common 
 celandine, in the form of a calcium-salt, together with malic acid and another acid, 
 probably fumaric : it is most abundant at the flowering time. To obtain it, the ex- 
 pressed juice is coagulated by heat and filtered. The filtrate is acidulated with nitric 
 acid, and nitrate of lead is added in small quantities, as long as a crystalline precipitate 
 falls, care being taken not to add too much either of the acid or of the lead-salt. The 
 precipitate, which contains lime, is diffused in a large quantity of water and decomposed 
 by sulphuretted hydrogen, which takes place slowly ; the solution of acid chelidonate 
 of calcium is neutralised with chalk and boiled with animal charcoal ; and the neutral 
 liquid is evaporated till saline crusts form. After cooling, white crystals are obtained, 
 of a silky lustre, which are to be purified by repeated crystallisation. To separate 
 the acid, the chelidonate of calcium thus obtained is dissolved in water, the solution 
 precipitated with carbonate of ammonia, and the concentrated solution of chelidonate 
 of ammonium mixed with twice its volume of moderately dilute hydrochloric acid. 
 Chelidonic acid is then precipitated as a mass of crystalline needles, which are to be 
 drained on a filter, washed, and purified by crystallisation from hot water. 
 
 Chelidonic acid thus prepared contains 2 at. water of crystallisation, C 7 II'0 B .2II 2 0. 
 which it gives off (amounting to 9 -2 per cent.) at J00 C., or when left over oil of 
 vitriol. By spontaneous evaporation it may be obtained in long needles containing 
 3 at. water (12*7 per cent.). It dissolves sparingly in cold, more freely in boiling 
 water, the solution solidifying as it cools. According to Probst, it requires for 
 solution 166 pts. of water at 6 C. and 26 pts. at 100. It dissolves in hydrochloric 
 and sulphuric acids more abundantly than in water, and in 700 pts. of 75 per cent. 
 alcohol at 12 C. 
 
 The acid dried at 100 C. gives off 2'0 per cent. (f at.) water at 150, probably 
 with partial decomposition. If the heat be continued, no further loss takes place 
 short of 210; but at that temperature the acid sustains a considerable though not 
 determinable loss; between 220 and 225 decomposition takes place, the residue 
 becoming soft, blackening, and giving off carbonic anhydride. The black mass, treated 
 with water, yields an acid which crystallises in yellowish crusts. Chelidonic acid 
 burns with slight detonation when heated in the air. It is scarcely attacked by strong 
 nitric acid : but moderately dilute nitric converts it, with evolution of nitric oxide 
 and carbonic anhydride, into another acid ; malic acid does not appear to be formed. 
 Chelidonic acid dissolves without decomposition in cold oil of vitriol ; but on the appli- 
 cation of heat, the solution becomes yellowish, and gives off gas-bubbles, assumes a 
 fine purple-red colour at the boiling heat, but after long boiling, gives off sulphurous 
 acid and acquires a dull undefinable colour. When the calcium-salt is boiled with 
 potash, oxalic acid is produced. (Lerch.) 
 
 CHELIDONATES. Chelidonic acid is a strong acid, dissolving zinc and iron, with evo- 
 lution of hydrogen, and decomposing carbonates. It is tribasic, its salts being trime- 
 t<t/fic, C 7 HM 8 0, dimctallic, C 7 H 2 M 2 6 , or monometallic, C 7 H 3 MO 8 , besides a few acid 
 salts containing C 7 H 3 M0 6 .C 7 H 4 8 . 
 
848 CHELIDONIC ACID. 
 
 The dimetallic chelidonates are formed when the acid is neutralised with a metallic 
 oxide or a carbonate ; with alkalis or their carbonates, trimetallic salts are apt to form. 
 Most of the dimetallic salts are soluble in water and crystallisable ; they contain 
 several atoms of water, which are given off at or above 150 C. ; the ammonium- and 
 silver-salts, however, become anhydrous at 100. Those which contain colourless 
 bases are themselves colourless. They have no action upon litmus. The monometallic 
 salts are produced by heating the dimetallic salts with about | of their weight of free 
 chelidonic acid or a dilute mineral acid. If the acid is in excess, acid salts are pro- 
 duced. The monometallic salts are resolved by repeated recrystallisation into acid and 
 dimetallic salts. The trimetallic salts are formed by treating the dimetallic salts with 
 a caustic alkali or alkaline carbonate. Those which contain colourless bases have a 
 fine lemon-yellow colour ; those which are soluble impart a deep colour to the water. 
 Most of them contain several atoms of water, which are not given off at 100 C. They 
 have no reaction upon litmus. They are decomposed by continued contact with water ; 
 those of the alkali-metals absorb carbonic acid from the air and yield a dimetallic 
 chelidonate and a carbonate. 
 
 The acid chelidonates crystallise from the solutions of the dimetallic salts in hot 
 hydrochloric acid, in delicate needles or scales, which do not give off their water of 
 crystallisation at 100C. They redden litmus, and may be recrystallised, but give up 
 their base when repeatedly treated with hydrochloric acid. 
 
 Chelidonate of Ammonium. C 7 H 2 (NH 4 ) 2 6 . A boiling dilute solution of the 
 dicalcic salt neutralised with carbonate of ammonium, filtered and evaporated, yields the 
 ammonium-salt, on cooling, in snow-white silky needles. The solution abandoned to 
 spontaneous evaporation, ultimately solidifies to a transparent mass, which when col- 
 lected and drained on a filter, yields the ammonium-salt in long capillary crystals re- 
 sembling a knot of the finest silver- white hair. It effloresces in contact with the air, 
 gives off 14-23 per cent. (2 at.) water at 100 C., and then exactly resembles sulphate 
 of quinine. (Lerch.) It does not give off ammonia, either when exposed to the 
 air at ordinary temperatures, or when heated to 100. Heated above 160, it turns 
 brownish and gives off carbonate off ammonium ; the residue does not contain any other 
 acid. By repeatedly evaporating the solution and redissolving the residue, it is 
 converted into the acid salt. It does not form a trimetallic salt when treated with 
 carbonate of ammonium or caustic ammonia. (Lerch .) 
 
 Chelidonates of Barium. The tribary tic salt, C 7 HBa 3 6 + 3 aq. (at 100), is 
 obtained by mixing a hot solution of the dibarytic salt with ammonia, precipitating 
 with chloride of barium, and quickly washing the precipitate with water. It is a 
 lemon-yellow powder which does not give off water at 100 C. It absorbs carbonic 
 acid from the air, dissolves sparingly in water, not at all in alcohol. 
 
 The dibarytic salt, C 7 H 2 Ba 2 6 + aq., is obtained by decomposing the corresponding 
 calcium-salt with a soluble barium-salt, or by neutralising the aqueous acid with 
 baryta or its carbonate. It is colourless, crystalline, and very brittle; soluble in 
 water. 
 
 The acid salt, C 7 H s Ba0 6 .C 7 H 4 8 + 2aq. is produced by dissolving the tribarytic salt 
 in boiling hydrochloric acid. 
 
 Chelidonates of Calcium. The tricalcic salt, C 7 HCa 8 8 + 3 aq. (at 100 C.) is 
 prepared by boiling the dicalcic salt with ammonia, or by decomposing the sodium-salt 
 mixed with ammonia with chloride of calcium. It is a yellow amorphous powder, 
 very little soluble in water, insoluble in alcohol. 
 
 The dicalcic salt, C 7 H J Ca 2 6 + 3 aq. (at 100), occurs in Chelidonium majus (p. 847). 
 It crystallises in silky prismatic needles, very little soluble in cold water, but easily in 
 boiling water ; insoluble in absolute alcohol. The solution does not affect litmus. The 
 salt is not efflorescent, and does not part with its water of crystallisation below 150 C. 
 
 The acid salt, C 7 H 3 Ca0 8 .C 7 H 4 6 + 2 aq., obtained by decomposing the preceding 
 with hydrochloric acid, crystallises in needles. 
 
 Chelidonate of Copper. Green sparingly soluble prisms, obtained by evapo- 
 rating a mixture of an alkaline chelidonate with sulphate of copper. 
 
 Chelidonates of Iron. The aqueous acid dissolves iron, forming ferrous cheli- 
 donate. 
 
 Ferric Chelidonate. Fe 4 3 .C 14 H 4 10 = 2C 7 H/e 3 6 + H 2 0. The solution of iron in 
 chelidonic acid passes to a higher degree of oxidation during evaporation, and deposits 
 a dingy yellow precipitate. The disodic salt forms with aqueous sesquichloride of iron, 
 a dingy yellow precipitate, somewhat soluble in acetic acid and in excess of sesquichlo- 
 ride of iron ; it does not diminish in weight at 100 C., and if set on fire at one point, 
 burns away with a sparkling light, leaving charcoal and sesquioxide of iron. (Lerch.) 
 
 When chelidonate of potassium is mixed with excess of sesquiehloride of iron, the 
 greater part of the feme chelidonate remains dissolved; the pale yellow filtrate 
 
CHELTDONIC ACID CHELIDONINE. 849 
 
 gradually assumes a darker colour, and ultimately becomes black-brown and opaque, 
 but recovers its pale yellow colour after some time ; on heating the liquid, the changes 
 of colour take place more quickly. The dark brown liquid forms with ammonia a 
 rusty brown precipitate, which becomes black when treated with a larger quantity of 
 ammonia, probably from formation of protoxide of iron. 
 
 Chelidonates of Lead. A. basic salt, 2C 7 HPb 3 6 .3Pb 2 0, is obtained by adding 
 the diplumbic salt mixed with ammonia to basic acetate of lead. 
 
 The triplumbic salt, C 7 HPb s 6 , is produced by treating the diplumbic salt with 
 ammonia, or by mixing a cold solution of dicalcic chelidonate with basic acetate of 
 lead. Yellowish-white flakes are then deposited containing g at. water (2C 7 HPb 3 6 . 
 3H 2 0), which is given off between 150 and 160 C., the salt then turning yellow. If 
 the solutions are mixed at the boiling heat, the anhydrous salt is produced at once in 
 the form of a lemon-yellow precipitate, darker in colour if mixed with the preceding. 
 It is decolorised and decomposed by acids. Insoluble in water and in alcohol, soluble 
 in lead-salts. 
 
 The diplumbic salt, C 7 H 2 Pb 2 6 + aq., is deposited, on mixing the dicalcic salt with 
 nitrate of lead, in small shining crystalline scales or slender needles, which are inso- 
 luble in water, soluble in lead-salts and in ordinary strong nitric acid, but not in fuming 
 nitric acid. 
 
 Chelidonate of Magnesium. Efflorescent needles, obtained by neutralising the 
 hot aqueous acid with carbonate of magnesium. 
 
 Chelidonates of Potassium. The tripotassic salt is deposited in yellow crys- 
 tals from a solution of the dipotassic salt mixed with caustic potash. It has no alkaline 
 reaction when pure, but absorbs carbonic acid from the air, and is converted into the 
 colourless dipotassic salt. Boiled with excess of caustic potash, it yields oxalate of 
 potassium. 
 
 The dipotassic salt is obtained by decomposing the dicalcic salt with carbonate of 
 potassium. 
 
 A clelidonate of calcium and potassium, C 7 HKCa 2 6 , is obtained by mixing a con- 
 centrated solution of the dicalcic salt with an equivalent quantity of carbonate of po- 
 tassium. In a very dilute solution, the lime is immediately precipitated as carbonate. 
 
 Chelidonates of Silver. The triargentic salt, C 7 HAg 3 6 , is obtained by precipi- 
 tating the tricalcic or the dicalcic salt, mixed with ammonia, with nitrate of silver. It 
 is a yellow very unstable precipitate. 
 
 The diargentic salt, C 7 H 2 Ag 2 6 , is produced by dissolving oxide of silver in cheli- 
 donic acid, or by precipitating the dicalcic salt with nitrate of silver and heating to 
 the boiling point. It then separates on cooling in long colourless needles resembling 
 acetate of silver. It is permanent in the air at ordinary temperatures, and is not 
 altered between 100 and 200 C. ; decomposes with slight detonation between 140 
 and 150. It dissolves in water, ammonia, and strong nitric acid, but not in alcohol. 
 
 Chelidonate of silver and calcium, C 7 HCaAg 2 6 ,is obtained by mixing a concentrated 
 ammoniacal solution of the dicalcic salt with a concentrated solution of nitrate of silver, 
 as a light yellow precipitate, which alters but little in drying, and is decomposed by 
 water only after long continued boiling. 
 
 Chelidonates of Sodium. The trisodic salt has not been obtained in definite 
 form. 
 
 The disodic salt, C'H 2 Na 2 6 + 4 aq., is prepared by decomposing the dicalcic salt 
 with carbonate of sodium ; carefnust be taken not to add too large an excess of the 
 latter, which would give rise to the simultaneous formation of trisodic chelidonate, and 
 a trimetallic salt containing both calcium and sodium, a reaction which is immediately 
 indicated by the yellow colouring of the liquid. 
 
 The disodic salt is very soluble in water both hot and cold, and is difficult to crys- 
 tallise. By slow evaporation, however, small prismatic needles are obtained, which 
 effloresce slowly when exposed to air. They contain 21 '16 per cent, water of crystal- 
 lisation, of which 15-5 per cent, goes off, at 100 C., the rest between 150 and 160. 
 
 The monosodic salt, C 7 H 3 NaO 6 + 2aq., is obtained in slender needles by treating the 
 disodic salt with chelidonic acid. 
 
 The disodic salt treated with boiling hydrochloric acid, yields slender needles or 
 scales, which appear to consist of an acid salt, C 7 H 3 Na0 6 .C 7 H 4 6 + 3aq. 
 
 Chelidonate of Strontium. Slender needles obtained by dissolving the carbo- 
 nate in chelidonic acid. 
 
 Chelidonate of Zinc. Obtained by saturating the acid with oxide of zinc; it is 
 crystalline, and has an acid reaction. 
 
 CKEZ.HXWIKTE. C' 20 H 19 N0 3 (?) (Godefroy, J. Pharm. Dec. 1824; Probst, 
 Ann. Ch. Pharm. xxix. 123; Real ing, ibid. 131; Will, ibid. xxxv. 113; G-erh. iv. 
 210.) An alkaloid contained in all parts of the Chelidonium mains, especially in the 
 
 VOL. I. 31 
 
850 CHELIDONINIC ACID CHEMICAL AFFINITY. 
 
 root. It is obtained by exhausting the root with water acidulated with sulphuric* 
 acid, precipitating by ammonia, dissolving the precipitate in alcohol acidulated with 
 sulphuric acid, reprecipitating by ammonia, and treating the residue with ether, 
 which dissolves chelerythrine (sanguinarine) and leaves chelidonine. To purify this 
 product, it is dissolved in the smallest possible quantity of water acidulated with sul- 
 phuric acid ; the solution is mixed with twice its volume of strong hydrochloric acid, 
 which, after a while, throws down a granular precipitate of hydrochlorate of chelidonine ; 
 the precipitate is digested with ammoniacal water, which sets the chelidonine at liberty ; 
 and the base thus obtained is crystallised from strong alcohol or better from acetic acid. 
 
 Chelidonine crystallises in small colourless tablets, insoluble in water, soluble in 
 alcohol and ether. It melts at 130 C. to a colourless oil, and decomposes at a higher 
 temperature. The crystals contain 2 at. crystallisation-water, which escapes entirely at 
 100 C. According to Will's analyses, the base dried at 100 contains 67'4 to 68-1 per 
 cent. C, 5-6 hydrogen, and 12*2 nitrogen; the formula C 20 H 19 N 3 3 requires 68'8 C, 
 5-4 H, 12-1 N, and 137 0. Water of crystallisation, by analysis, 46*5 to 5'13; by cal- 
 culation 4-91. 
 
 Chelidonine dissolves readily in acids, forming salts which have a bitter taste and 
 redden litmus. Its compounds with the weaker acids, such as the acetate, are decom- 
 posed by evaporation. Ammonia added to solutions of the salts throws down a bulky 
 curdy precipitate, which after a while contracts into a granular crystalline mass. The 
 salts are likewise precipitated by tincture of galls. 
 
 According to Probst, solutions of chelidonine are not poisonoiis. 
 
 Hydrochlorate of chelidonine is crystallisable, and dissolves in 325 pts. of water at 
 18 C. The chloroplatinate, C 20 H 19 N s 3 .HCl.PtCl 2 , is a flocculent, afterwards granular 
 precipitate, yielding by analysis 17'42 and 17'60 per cent, platinum, the formula re- 
 quiring 1777. 
 
 The nitrate is sparingly soluble in water ; the sulphate and phosphate are very soluble 
 both in water and in alcohol : all three salts are crystallisable. 
 
 The acetate is obtained by decomposing the sulphate with acetate of barium : it is 
 very soluble in water and alcohol, and dries up to a gummy mass. 
 
 CHBLIDONINIC ACID. C 7 H 10 6 ? (Zwenger, Ann. Ch. Pharm. cxiv. 350). 
 This is another acid contained in very small quantity in Chclidonium majus. When 
 the decoction of the plant acidulated with acetic acid, is treated with neutral acetate 
 [or nitrate] of lead, chelidonic acid is precipitated, and chelidoninic acid remains in 
 solution ; and by treating the filtrate with basic acetate of lead, not in excess, decom- 
 posing the precipitate with sulphuretted hydrogen, evaporating the filtrate, extracting 
 with ether, and again evaporating, chelidoninic acid is obtained in hard, mammellated, 
 yellow crystals. It dissolves easily in water, alcohol, and ether, and separates from 
 the aqueous solution in hard, white, anhydrous crystals, having the form of an oblique 
 rhomboi'dal prism. It has a strongly acid taste, decomposes carbonates, and dissolves 
 iron, with evolution of hydrogen. It melts at 195 C. ; its vapour is extremely irri- 
 tating. With nitrate of silver, it forms a white, crystalline, sparingly soluble preci- 
 pitate. Nitric acid converts the acid into oxalic acid. Zwenger assigns to crystallised 
 chelidoninic acid the formula C"H U 13 ; it may perhaps be C U H } O^.HO, or 
 2C'H 10 0.H 2 0. 
 
 A yellow bitter substance contained in the root, leaves, 
 and flowers of Chelidonium majus. It is obtained by precipitating the juice with sub- 
 acetate of lead, decomposing the precipitate with sulphuretted hydrogen, and exhaust- 
 ing the sulphide of lead with boiling water. It crystallises in confused needles, but 
 more frequently forms a yellow friable mass. It is sparingly soluble in cold, moderately 
 soluble in boiling water. The solutions are yellow and very bitter, and are not altered 
 either by acids or by alkalis. (Probst, loc. cit.) 
 
 CHXHMUCCAXi AFFIMTTY. Chemical Attraction, Chemical Force, Elective At- 
 traction, Elective Affinity ; Ch"mische Kraft, Verwandtschaft, Wahlvcrwandtschaft, 
 WahlanzieMng;Affinitas, Attract/o Electiva; Affinite. Affinity is that power by virtue 
 of which bodies of dissimilar nature unite together to form compounds of definite con- 
 stitution, which cannot be destroyed by mechanical agencies, and are, for the most 
 part, dissimilar in properties to the elements from which they are produced. Whether 
 this force is of peculiar nature, distinct from all others, or only a modification of the 
 power which, under various circumstances, shows itself as light, heat, electricity, mag- 
 netism, mechanical force, &c., is a question still undecided. That it is intimately re- 
 lated to heat and electricity, is manifest from the whole range of chemical phenomense ; 
 indeed no chemical change can take place without a corresponding alteration in the tem- 
 perature and electrical state of the bodies concerned. The conclusion to which the pro- 
 gress of discovery appears to tend, is that chemical action, heat, electricity, and all 
 other manifestations of force result from certain movements in the ultimate particles of 
 bodies, and are accordingly convertible into the other. Thi.s idea will be further deve- 
 
CHEMICAL AFFINITY. 851 
 
 loped in the articles HEAT, LIGHT, and ELECTEICITY ; for the present, while we are 
 treating of phenomena purely chemical, it will be convenient to speak of affinity as if it 
 were a distinct force. 
 
 The terms affinity and chemical combination are not used by all writers in exactly 
 the same sense. L. G-melin defines affinity as "the power by virtue of which bodies 
 of dissimilar nature combine together into a whole, which appears perfectly uniform to 
 the senses, even when assisted by the most powerful instruments" (Handbook, i. 33). 
 Accordingly he applies it to mixtures of liquids, as of alcohol and water, alcohol and 
 volatile oils, &c., and to solutions of solids in liquids, as of salts in water, resins in 
 alcohol, fec., as well as to combinations in definite proportion. Most chemists, how- 
 ever, make a distinction between mixtures and solutions on the one hand, and com- 
 pounds formed in definite proportions on the other, restricting the term " chemical 
 affinity " to the force, whatever it may be, that is concerned in the formation of the 
 latter. In favour of Grmeliu's view, it may be alleged that mixtures of liquids and so- 
 lutions resemble chemical compounds, commonly so called, in these respects, that they 
 are perfectly uniform in colour, density, refractive power, and other physical characters, 
 and that the force which holds the heterogenous particles together in them is sufficient 
 to resist any tendency to separate arising from difference of density (e. g. a mixture of 
 water and alcohol, never separates into two layers, like oil and water), and can only be 
 overcome by the same means as are applied to the destruction of the more intimate kind 
 of combinations, viz. heat, or the superior affinity of another substance, as when resin 
 is precipitated from its solution in alcohol by addition of water, or carbonate of potas- 
 sium from its aqueous solution by alcohol. 
 
 There are, however, several well marked characters by which chemical combination 
 of the more intimate kind, such as that of oxygen and hydrogen in water, hydrogen 
 and nitrogen in ammonia, sulphur and mercury in cinnabar, &c., is distinguished from 
 mere mixture or solution. These distinctions relate to the proportions in which the 
 constituents of the compound are united, to the character of the compound, and to the 
 circumstances attending its formation and decomposition. 
 
 1. As regards proportion. Mixture and solution follow a law of continuity. Mis- 
 cible liquids, such as alcohol and water, may be mixed in any proportions whatever, 
 and a solid dissolves in a liquid in all proportions, up to a certain limit, the point of 
 saturation : but chemical combination, properly so called, takes place in certain definite 
 proportions and no others. Thus hydrogen and chlorine unite only in the ratio of 1 pt. 
 by weight of hydrogen to 35-5 pts. of chlorine ; oxygen and carbon, only in the ratio 
 of 6 pts. carbon to 8 and 16 pts. oxygen ; nitrogen and oxygen, as 14 pts. nitrogen to 
 8, 16, 24, 32 and 40 pts. oxygen; lead and oxygen as 103*5 lead to 8, lOf, and 
 16 pts. oxygen, mercury and sulphur as 100 mercury to 8 and 16 pts. sulphur, &c. &c. 
 In all cases, indeed, the number of compounds formed by any two elements is definite, 
 and combination never takes place in any intermediate proportions. 
 
 The law which regulates the proportions of the several compounds of the same two 
 bodies is called the "Law of Multiples," and may be thus expressed: The several 
 proportions in which two bodies, A and B, unite, may be represented by the formulae 
 A + B, A + 2B, A + 3B, . . . A > nB, or 2A + 3B, 2A + 5B, . . . 3A + 4B, . . . or in 
 general mA. + nB ; where m and n are integer numbers in most cases not exceeding 7, at 
 least in inorganic compounds.* We have seen in the article ATOMIC WEIGHTS (p. 452), 
 that it was the observation of these proportions which led Dalton to the idea of the 
 atomic theory. In short, if the ultimate atoms of the several elements be supposed to 
 possess certain invariable relative weights, and to unite and form chemical compounds 
 by simple juxtaposition, in the proportion of 1 : 1, 1 : 2, 2 : 3, &c., the law just enun- 
 ciated follows as a matter of course. It is possible that the distinction between true 
 chemical combination and mixture may be found in this : that combination takes 
 place between ultimate atoms ; mixture between the physical molecules of bodies, which 
 are complex aggregates of atoms. 
 
 2. As to the character of the product. The properties of a mixed liquid, as the colour, 
 taste, specific gravity, refracting power, &c., are always intermediate between those of 
 its components. In solutions also, the dissolved body imparts to the solvent its taste and 
 colour, in proportion to the quantity dissolved, the density of the solution also increasing 
 regularly and continuously with the amount of solid matter taken up ; but definite 
 chemical compounds generally differ altogether in physical properties from their com- 
 
 * The combining proportions of the elements of organic compounds are regulated by much more 
 complex laws. In the scries of fatty acids, for example, we find the same quantity of oxygen (8 pts.) 
 associated with 3, 2x3, 3x3, 4x3, 5x3, ... 30x3 parts of carbon ; and if, in addition to this, we con- 
 sider the various proportions of C, H, N, and (), existing in the numerous series of organic bodies, it 
 may fairly be concluded tliat the constitution of these bodies would never have suggested the law of 
 multiples, as above stated. Indeod.it is only by introducing the hypothesis of compound radicles, that 
 the composition of organic bodies can be assimilated to that of inorganic compounds. (See GKGANIC 
 COMI-UUNDS and KAUICLKS.) 
 
 3 I 2 
 
852 CHEMICAL AFFINITY. 
 
 ponents. Thus, with regard to colour : yellow sulphur and grey mercury produce red 
 cinnabar ; purple iodine and grey potassium yield colourless iodide of potassium ; 
 purple iodine and grey lead form bright yellow iodide of lead ; the colours of metallic 
 oxides bear no relation whatever to those of the metals themselves, and the compounds 
 of metals with chlorine, iodine, and other salt-radicles, are for the most part trans- 
 parent, though the metals themselves are opaque. Again, we find organic compounds 
 exhibiting an endless variety of colours, formed by the union of elements which in the 
 free state have no colour at all. The density of a compound is very rarely an exact 
 mean between that of its constituents, being generally higher and in a few cases lower ; 
 and the taste, smell, refracting power, fusibility, volatility, conducting power for heat 
 and electricity, and other physical properties, are not for the most part such as would 
 result from mere mixture of their components. It must not of course be understood 
 that the physical properties of compounds are not related to those of their components 
 by any regular laws. Definite relations doubtless exist, and will one day be discovered : 
 indeed, the regular gradations of boiling point, atomic volume, &c., exhibited by the 
 terms of homologous series of organic compounds, afford striking examples of them ; 
 still it is generally true that the properties of a definite compound are not interme- 
 diate between those of its components, as in a mixture or solution. 
 
 3. As to the phenomena which accompany the formation and decomposition of chemi- 
 cal compounds, especially as regards temperature. Chemical combination in definite 
 proportions, is always attended with evolution of heat, sometimes amounting to vivid 
 combustion, and decomposition is accompanied by absorption of heat and consequent 
 reduction of temperature ; whereas the mere mixing of liquids takes place without 
 change of temperature, and the solution of a solid in a liquid, though partaking of the 
 nature of combination, is attended with reduction of temperature, due to the passage 
 of the body from the solid to the liquid state. So much is this the case, that a rise of 
 temperature attending the contact of a solid and a liquid, may always be regarded as 
 an indication of the formation of a definite compound ; thus there are many anhydrous 
 salts, such as chloride of calcium and sulphate of copper, which become strongly heated 
 by contact with water, being at the same time converted into hydrates ; but these 
 hydrates, in subsequently dissolving in the water, produce a considerable degree of cold. 
 (See HEAT.) 
 
 The formation and resolution of chemical compounds are also attended with 
 changes in the electrical state of their elements. Whether the direct combination of 
 two elements produces any electrical disturbance, is not perhaps clearly made out, on 
 account of peculiar difficulties in the investigation of the phenomena (see ELECTRICITY) ; 
 but the solution of a metal in an acid, which consists in the decomposition of one 
 compound and the formation of another, calls into action a large amount of electric 
 force, which by certain arrangements, hereafter to be considered, may be made to take 
 the form of an electric current. Conversely, an electric current, no matter how deve- 
 loped, whether by chemical action, or by friction, or by magnetic induction, is capable 
 of overcoming the most powerful chemical combinations, and causing the elements to 
 travel through the circuit in opposite directions, and finally separate at the poles of 
 the circuit. No such effect is, however, produced on mixtures or solutions. The 
 passage of an electric current through the solution of a salt, resolves that salt into 
 its elements, but never causes it to separate from the water as a whole. 
 
 For these reasons, we shall restrict the term CHEMICAL COMBINATION, to the forma- 
 tion of compounds in definite proportion, and AFFINITY, to the force which is concerned 
 in their production, and proceed to consider more particularly the circumstances and 
 results of chemical combination and decomposition. 
 
 Every elementary body is capable of uniting with others, and for the most part 
 with every other. It is true that some of the compounds, as those of carbon with 
 certain metals, of boron with silicon, selenium, and phosphorus, and of iodine with 
 carbon, have either not been formed or are but imperfectly known ; but there can be 
 little doubt of the possibility of their formation. The compounds of fluorine with some 
 of the other non-metallic elements are least known, on account of the difficulty of 
 manipulating with fluorine in the free state. 
 
 Compounds resulting from the union of two simple substances, are called binary 
 compounds of the first order ; such are the metallic chlorides, oxides, and sulphides, the 
 chlorides of hydrogen, sulphur, phosphorus, &c. Now, these compounds are capable of 
 uniting with each other in various ways like elementary bodies, and hence result com- 
 pounds containing three or four elements, which may be regarded as binary compounds 
 of the second order ; such are double chlorides, KCl.PtCF ; oxygen-salts, as Ba"O.S0 3 ; 
 sulphur-salts K 2 S.As 2 S 2 ; hydrated chlorides CaC1.3H 2 O, &c., and again these com- 
 pounds of the second order may be conceived as uniting together to form compounds of 
 the third order, such as double salts, e. q. common alum, which contains sulphate of 
 potassium and sulphate of aluminium, K 2 O.S0 3 -t- A1 4 3 .380*. Further than this, the 
 power of combination does not appear to extend. 
 
CHEMICAL AFFINITY. 853 
 
 This view of the successive building up of chemical compounds in binary groups, 
 called the Dualistic Theory is, however, not the only one that can be taken, or indeed 
 that which accords best with the present state of knowledge. It is for many reasons 
 better to regard all compounds, whether containing two, three, or more elements, as 
 constituted according to certain typical forms ; for example, chlorides, iodides, bro- 
 mides, and cyanides, as formed on the type of hydrochloric acid HC1 ; acids, bases, 
 and salts containing oxygen or sulphur, seleniumn or tellurium, as formed on the 
 type of water HH.O, &c. This is called the Unitary Thiory. (See CLASSIFICATION, 
 KADICLES, SUBSTITUTION, TYPES, and the various articles in which particular com- 
 pounds are described.) It is true, indeed, that compounds containing three or more 
 elements may, in many instances, be formed by the direct union of binary compounds 
 of the first order ; thus double chlorides and iodides are formed by fusing together the 
 component simple chlorides, or by mixing their aqueous solutions and leaving them to 
 crystallise ; sulphur-salts, such as Na 2 S.As'-S 3 , by fusing together the simple sulphides ; 
 oxygen-salts also, in some instances, by heating together the so-called anhydrous 
 acid and the base; thus boric anhydride and magnesia fused together in the proper 
 proportion form borate of magnesium, 3Mg 2 O.B"0 3 or Mg'BO 3 ; and anhydrous baryta 
 heated in vapour of sulphuric anhydride, burns and forms sulphate of barium, Ba^O.SO 3 
 or Ba 2 S0 4 . But it by no means follows that the arrangement of the atoms in the resulting 
 compound must be the same as in the simpler compounds from which it is formed ; 
 thus, while the mode of formation of sulphate of barium just mentioned would lead 
 to the supposition that it is Ba 2 O.SO 3 , other modes of formation, and most of its 
 reactions, indicate rather that its constitution is represented by the formula Ba 2 .S0 4 or 
 S0 2 .Ba 2 .0 2 . 
 
 These observations apply chiefly to inorganic compounds. Organic bodies, with 
 the exception of cyanogen and the hydrocarbons, all contain at least three elements, 
 and the dualistic view of the building up of compounds by pairs cannot be applied 
 to them at all, excepting on the supposition that they contain certain compound 
 radicles, such as ethyl, C 2 H 5 , benzoyl, C 7 H 5 0, &c., which play the same part as metals in 
 inorganic compounds, uniting like simple radicles, with oxygen, chlorine, bromine, &c. 
 With the help of these radicles, some of which have been obtained in the free state, 
 the constitution of the best known organic compounds, such as the alcohols, ethers, 
 aldehydes, acetones, and their derivatives, may be assimilated to that of inorganic 
 compounds, and represented either on the unitary or the dualistic view. 
 
 Formation and Decomposition of Chemical Compounds. 
 
 As chemical combination involves a total change in the arrangement of the atoms of 
 the combining bodies, it is clear that cohesion, which tends to hold them in certain fixed 
 positions, must be opposed to chemical union, and on the contrary, anything which gives 
 mobility to the particles of the two bodies, and enables them to intermix and approach 
 within small distances of each other, such as pulverisation, and more especially lique- 
 faction, must tend to promote it. 
 
 a. Generally speaking, one at least of the combining bodies must be either in the liquid 
 or in the gaseous state, and if it be not so at ordinary temperatures, it must be brought 
 into that state by elevation of temperature. Solid bodies either do not combine at 
 all, or their combination is attended with great difficulty, because, from the immobility 
 of their particles, their points of immediate contact are but few, and the exceedingly 
 thin film of compound which may be formed at such points, acts as a partition to pre- 
 vent further contact and consequently further combination. But by continued rubbing, 
 which renews the points of contact, more complete combination may often be effected : 
 in this manner, finely divided copper may be made to combine with sulphur, the com- 
 bination being even attended with rise of temperature. If, on the other hand, the 
 compound formed by the two solids is itself fluid, its mobility gives rise to continu- 
 ally renewed contact, and combination goes on. Thus ice under C. unites with chlo- 
 ride of sodium and other salts, and solid amalgam of lead with solid amalgam of bismuth. 
 Crystallised oxalic acid and lime may be made to combine by rubbing them together, 
 because the acid contains more water of crystallisation than the oxalate of calcium 
 produced is able to take up : hence, at the beginning of the action, a little water is set 
 free and dissolves the oxalic acid. In some cases it is sufficient to heat one of the 
 solid bodies till it softens : thus iron surrounded with charcoal and heated to white- 
 ness is slowly penetrated by the charcoal (Cementation). When, in consequence of one 
 or both bodies being in the fluid state, combination takes place at the ordinary tempera- 
 ture or a little above it, it is called solution in the wet way (Solutio via humida) : if a 
 higher temperature is required, the process is called solution in the dry way, fusion 
 (Solutio via sicca, Confusio}. 
 
 b. Even if one or both of the bodies be in the fluid state, a higher temperature is 
 often necessary to effect the combination. 
 
 3 i 3 
 
854 CHEMICAL AFFINITY. 
 
 Melted sulphur will not combine with carbon ; the sulphur must be brought in the 
 State of vapour into contact with red-hot charcoal, although the elasticity of the vapour 
 might rather be expected to interfere with the combination. Neutral carbon ate of 
 of sodium, in the efflorescent state absorbs carbonic acid very slowly at first, but more 
 and more quickly as it gets heated by the absorption, and ultimately with great 
 violence. Charcoal requires to be heated before it will burn in oxygen gas, that is, 
 before it will combine with the oxygen. At ordinary temperatures, oxygen may be 
 mixed with hydrogen and other inflammable gases without combining with them, but 
 at a red heat, combination takes place immediately. In this case both bodies are fluid, 
 and we might expect that heat, by increasing their elasticity, would rather oppose than 
 favour the combination. The manner in which heat acts in such cases is not precisely 
 understood ; but its effect is probably due to the increased rapidity of movement which 
 it gives to the particles. (See HEAT.) 
 
 c. In some cases, light has the same effect as an elevation of temperature ; thus 
 chlorine, under the influence of light, unites directly with hydrogen or carbonic oxide. 
 
 d. Electricity likewise favours the combination of many substances, especially of 
 gases, acting chiefly, perhaps, by elevation of temperature. In this manner the com- 
 bination of oxygen with hydrogen, carbonic oxide or carburetted hydrogen, and of 
 chlorine with hydrogen, is easily brought about. 
 
 e. In some instances, the expansion of gaseous bodies favours their combination with 
 others. Phosphorus undergoes slow combustion in oxygen gas, however low the tem- 
 perature may be, the action going on more quickly as the gas is more rarefied ; a mixture 
 of oxygen and non-inflammable phosphoretted hydrogen gases explodes on expansion. 
 
 f. The presence of a solid body, particularly a metal, having a great extent of 
 surface, likewise causes, sometimes at ordinary, sometimes at slightly elevated tem- 
 peratures, the combination of oxygen with inflammable gases and vapours, which 
 would otherwise take place only at a red heat. This property is most strikingly ex- 
 hibited by platinum ; the more finely divided the platinum, the stronger is its action. 
 When the combination of oxygen with inflammable gases take place at its surface, the 
 heat developed raises its temperature and thereby increases its activity, till at length 
 the metal becomes red-hot and then sudden combination occurs. Platinum appears to 
 condense gases, particularly oxygen, on its surface, whereby the heterogenous atoms are 
 made to approach one another and combine. A similar power is possessed by charcoal 
 and other porous bodies (p. 761). 
 
 A body in the act of chemical combination often exhibits the power of inducing the 
 same kind of activity in another body and causing it to combine with a third body, 
 thereby forming a compound which, under the existing circumstances, would not have 
 been formed without the presence of the first body (Liebig, Ann. Ch. Pharm. xxx. 
 262). Nitrogen gas does not by itself combine with oxygen, even when heated ; but 
 if a mixture of nitrogen and hydrogen be set on fire, the hydrogen burns, producing 
 water, and a portion of the nitrogen combines at the same time with oxygen, producing 
 nitric acid. Pure copper does not dissolve in dilute sulphuric acid, but when com- 
 bined with zinc and nickel (in German silver), metals which decompose acidulated 
 water, or when combined with three times its weight of zinc only, it dissolves com- 
 pletely together with the other metals. Platinum when alone does not dissolve in 
 nitric acid, but when alloyed with silver it becomes soluble in that acid. 
 
 Chemical compounds may be formed, either by direct union of their elements, or by 
 substitution of one element for another in a compound previously existing. 
 
 Oxygen unites directly with most other elements, either at ordinary or at elevated 
 temperatures ; so likewise do sulphur, chlorine, iodine, and bromine. Hydrogen unites 
 directly with oxygen and chlorine at elevated temperatures, with the latter also at 
 ordinary temperatures, under the influence of light ; nitrogen shows but little tendency 
 to unite directly with any other element ; phosphorus unites readily with oxygen, 
 chlorine, iodine, and bromine at ordinary temperatures ; with sulphur and selenium 
 with aid of a moderate heat. Carbon, at high temperatures, unites directly with 
 oxygen, sulphur, and many metals, not with any other element. Boron and silicium 
 combine directly with oxygen at ordinary temperatures, if they are in a state of 
 minute division, more easily when heated; with other elements they exhibit little or 
 no power of direct combination. Metals unite directly with oxygen, sulphur, selenium, 
 chlorine, bromine, and iodine, sometimes at ordinary, sometimes at higher tempera- 
 tures ; in some instances also with phosphorus and with carbon. Alloys of definite 
 constitution are also frequently produced by melting different metals together, though 
 the greater number of such products are merely mixtures. 
 
 It has been already mentioned that compound bodies can unite with one another 
 directly, forming new bodies of more complex constitution. These combinations aro 
 sometimes very energetic, as that of anhydrous baryta heated in the vapour of sul- 
 phuric anhydride, which is a true case of combustion. 
 
CHEMICAL AFFINITY. 655 
 
 Altogether, however, the cases in which compounds are formed by direct union of 
 elements is small compared with that in which new compounds result from the trans- 
 formation of others previously existing. Such transformations may be effected in 
 various ways. 
 
 I. By heat, which may either expel one or more of the elements of the original com- 
 pound in the free state, leaving the rest in a new form of combination, or may cause 
 the whole of the elements to arrange themselves in the form of new compounds.: 
 1. Chlorate of potassium, KC10 3 , exposed to a full red heat, gives off the whole of its 
 oxygen, and is converted into chloride of potassium, KC1. Similarly with other chlo- 
 rates, also with bromates and iodates. Many metallic oxides and sulphides, when 
 heated to redness, give off part of their oxygen or sulphur, and are reduced to lower 
 oxides or sulphides. 2. Chlorate of potassium exposed to a degree of heat less than 
 sufficient to expel the whole of the oxygen, is resolved into perchlorate and chloride 
 of potassium : 3KC10 3 = KC1 + 2KC10 4 + 0. Nitrate of ammonium, NH 4 .N0 3 , is 
 resolved by heat into water, 2H 2 0, and nitrous oxide, N 2 0. To this head likewise 
 belong the numerous transformations of organic compounds, resulting from dry or 
 destructive distillation. 
 
 II. By electricity. The action of the electric current on chemical compounds, either 
 in the fused state or in solution, gives rise to an endless variety of new products. In 
 some instances, the elements of a compound are eliminated by electrolysis in the free 
 state, as when water, hydrochloric acid, or certain metallic oxides, chlorides, or iodides 
 are subjected to the action of the current ; frequently, however, the elements arrange 
 themselves in new combinations. "We shall consider this subject more fully under 
 ELECTKICITY ; at present we will merely mention the formation of peroxide of lead at 
 the positive pole, when a solution of nitrate or acetate of lead is electrolysed ; the evo- 
 lution of arsenetted hydrogen in the electrolysis of aqueous arsenious acid ; and the 
 decompositions of acetic acid and other fatty acids, into alcohol-radicles, hydrocarbons 
 of the ethylene-series, carbonic anhydride, and hydrogen. 
 
 III. By the action of another substance, simple or compound. 
 
 a. The decomposing substance is an element (or a compound acting as such), and 
 takes the place of one element of the compound, which is thereby eliminated. This is 
 SIMPLE SUBSTITUTION. 
 
 Zinc decomposes hydrochloric acid, HC1, forming ZnCl, and expelling hydrogen. 
 Potassium decomposes water, HHO, expelling half the hydrogen, and forming hydrate 
 of potassium, KHO. Chlorine decomposes bromide of silver, forming chloride of 
 silver and eliminating bromine. Metals in numerous instances displace other metals 
 from solutions of their salts, e. g. iron decomposes nitrate of copper, forming nitrate of 
 iron and a deposit of copper. Silicic anhydride, SiO 2 , decomposes carbonate of soda, 
 Na 2 O.C0 2 , expeDing carbonic anhydride, and forming silicate of soda, Na'O.SiO 8 , 
 though not exactly in the proportion here indicated. Boric anhydride, B 2 3 , heated 
 with hydrate of barium expels 3 atoms of water, and forms borate of barium : B 2 3 + 
 3(H 2 O.Ba 2 0) = 3Ba' 2 O.B 2 3 + 3H 2 0. 
 
 b. The acting body sometimes enters into combination with both elements of the 
 compound, or with the compound as a whole. 
 
 Sulphide of carbon burnt in oxygen, produces sulphurous and carbonic anhydrides. 
 Hydrocarbons and organic compounds in general, yield by combustion, carbonic anhy- 
 dride and water. Chlorine converts metallic sulphides into chloride of sulphur and 
 metallic chlorides. Chlorine passed into water forms hydrochloric and hypochlorous 
 acids ; it decomposes metallic oxides in like manner, forming with mercuric oxide, 
 Hg O, for example, chloride of mercury, 2HgCl, and hypochlorous anhydride, C1 2 0. 
 Sometimes only one compound is formed : as when a metallic sulphide is heated in the 
 air and converted into a sulphate : e. g. Cu*S + O 4 = Cu 2 S0 4 ; or again, when phos- 
 phoretted hydrogen, PH 3 , is converted by combustion into phosphoric acid, PH 3 4 . 
 
 c. The substance by which the compound AB is decomposed, is itself a compound 
 CD, and the transformation consists in an interchange of elements, whereby the two 
 new compounds AD and BC, are produced. This is DOUBLE DECOMPOSITION. It is the 
 most frequent of all kinds of chemical action, and, as we shall presently explain, may 
 be regarded as typical of the rest. Instances of it may be adduced without number, 
 such as the mutual decomposition of neutral salts, c. g. chloride of barium and sulphate 
 of copper ; nitrate of silver and chloride of sodium, &c. Also the decomposition of 
 metallic oxides by acids, resulting in the formation of chlorides, iodides, sulphides, &c. 
 and oxygen-salts : thus, with hydrochloric acid and oxide of copper : 
 
 Cu 2 + H'Cl 2 = Cu 2 Cl 2 + H 2 0; 
 hydrochloric acid and hydrate of potassium : 
 
 KHO + HC1 = KC1 f HHO ; 
 3i 4 
 
856 CHEMICAL AFFINITY. 
 
 sulphydric acid and oxide of lead : 
 
 H 2 S + Pb 2 = H 2 + Pb 2 S. 
 Sulphuric acid and protoxide of iron : 
 
 H 2 S0 4 + Fe 2 = Fe 2 S0 4 + H 2 ; 
 sulphuric acid and sesquioxide of iron : 
 
 3H 2 S0 4 + Fe 4 3 = Fe 4 (S0 4 ) 3 -f 3H 2 0. 
 
 Similarly when compound radicles are concerned, as in organic compounds : e. g. the 
 formation of water and chloride of ethyl by the mutual action of alcohol and hydro- 
 chloric acid : 
 
 + HC1 = C 2 H 5 C1 + H 2 0; 
 
 of ethylsulphuric acid and water, from alcohol and sulphuric acid : 
 
 of thiacetic acid and phosphoric anhydride, from acetic acid and pentasulphide of 
 phosphorus : 
 
 of ethylamine by the action of hydrate of potassium on cyanate of ethyl : 
 
 'jjSSf * 
 
 Cyanate of Hydrate Carbonate Ethyl- 
 
 ethyl. ofpotas- ofpotas- amine. 
 
 slum. slum. 
 
 In some cases, the decomposition of a compound, AB, is effected by the joint action 
 of two substances C, D, not previously combined ; as when an oxide, alumina, for ex- 
 ample, is decomposed by the joint action of chlorine and carbon at a red heat, yielding 
 a chloride and carbonic oxide : 
 
 A1 4 3 + Cl + C 3 = 2APC1 3 + 300. 
 
 Sometime?, instead of the two new compounds AD, BC, being produced, only one 
 such compound, AD, is formed, the elements B C being either set free or entering into 
 other combinations. Thus when chloride of ammonium is decomposed by quick lime, 
 the products should be chloride of calcium and oxide of ammonium ; but the latter 
 is immediately resolved into ammonia and water : 
 
 2NH 4 C1 + Ca 2 = 2CaCl + (NH 4 ) 2 [= 2NH 3 + H 2 0]. 
 
 Aluminium and other sesquiatomic metals do not form carbonates : hence, when a 
 salt of aluminium is precipitated by an alkaline carbonate, the precipitate consists, not 
 of carbonate of aluminium, but of alumina (hydrated), while carbonic anhydride is set 
 free: 
 
 2APC1 3 + 3Na 2 C0 3 = 6NaCl + A1 4 3 + 3 CO 2 . 
 
 Many peroxides heated with hydrochloric acid, yield water, a protochloride of the 
 metal, and free chlorine, the metal not forming a chloride analogous in composition to 
 the peroxide: 
 
 MnO + 2HC1 = H 2 + MnCl + Cl. 
 
 In many cases, one or both of the new products, AD, BC, enters into combination 
 with an undecomposed portion of one or both of the original compounds, the particular 
 products formed depending upon the proportion in which the original substances are 
 present, and on the circumstances of the experiment. Thus, when sulphide of carbon 
 is decomposed by potash, the immediate products are sulphide of potassium and 
 carbonic anhydride ; but these unite with portions of the original substances, forming 
 carbonate and sulphocarbonate of potassium : 
 
 3CS 2 + 3K 2 = K 2 O.C0 2 + 2(K 2 S.CS 2 ). 
 
 Sulphide of antimony fused with potash, yields at first sulphide of potassium and oxide 
 of antimony ; but the final products are oxysulphide of antimony and sulphantimonite 
 of potassium : 
 
 3Sb 2 S 3 + 3K 2 = Sb 2 3 .Sb 2 S 3 + 3K 2 S.Sb 2 S 3 ; 
 
 but when 4 at. trisulphide of antimony are fused with 7 at. potash, the products are 
 2 at. sulphantimonite and 1 at. acid antimonite of potassium : 
 
 4Sb 2 S + 7K 2 = 2(3K 2 S.Sb 2 S 3 ) -I- K*0.2Sb 2 O s . 
 
CHEMICAL AFFINITY. 857 
 
 It has already been stated that double decomposition may be viewed as a type of 
 chemical action in general ; in fact, all cases of simple substitution, and even of the 
 direct union of two elements, or the separation of the elements of a binary compound, 
 may be viewed as double decompositions, provided we make certain suppositions re- 
 specting the constitution of elements in the free state. 
 
 There are many considerations which tend to show that the atoms of an elementary 
 body, or of a compound radicle in the free state, are associated by pairs in a similar 
 manner to the heterogenous atoms of a binary compound ; that is to say, a molecule 
 of free hydrogen consists of HH, and a molecule of free ethyl of C 2 H 5 .C 2 H 5 , just as a 
 molecule of hydrochloric acid consists of HC1, and a molecule of chloride of ethyl of 
 C 2 H*.C1. In the voltaic circuit, the metallic conductor exhibits in many respects the 
 same phenomena as the electrolyte, both parts of the circuit becoming heated, and 
 both producing the same deflection of a magnetic needle placed near them : hence 
 it may be inferred, that the metallic conductor consists of a series of similar particles 
 polarised in pairs, just as the electrolyte consists of a series of heterogeneous particles 
 thus polarised. In a circuit composed of zinc, platinum, and hydrochloric acid, 
 
 - + - + + 
 the electrolyte may be regarded as consisting of C1H C1H C1H . . . and the 
 
 _+_+_+ _+_ + 
 
 metallic part of the circuit of ZnZn ZnZn ZnZn . . . PtPt PtPt . . . the entire 
 circuit being thus made up of atoms in opposite polar states. This, as will be more fully 
 explained in the article ELECTRICITY, is the most satisfactory idea that can be given 
 of the phenomena of electro-chemical action. 
 
 But there are also considerations purely chemical which tend to the same conclusion. 
 Many instances of chemical action are known, in which two atoms of an elementary 
 body or compound radicle unite together at the moment of chemical change, just like 
 heterogeneous atoms. 
 
 Thus, when hydride of copper, Cu 2 H, is decomposed by hydrochloric acid, cuprous 
 chloride is formed, and a quantity of hydrogen evolved, equal to twice that which is 
 contained in the hydride itself: 
 
 Cu 2 H + HC1 = Cu 2 Cl -i- HH. 
 
 This action is precisely analogous to that of hydrochloric acid on cuprous oxide : 
 Cu<0 + 2HC1 = 2Cu 2 Cl + H 2 0. 
 
 In the latter case, the hydrogen separated from the hydrochloric acid unites with oxy- 
 gen ; in the former, with hydrogen. "When solutions of sulphurous and sulphydric 
 acids are mixed, the whole of the sulphur is precipitated : 
 
 SO 2 + 2H 2 S = 2H 2 + S.S 2 , 
 
 the action being similar to that of sulphurous acid on selenhydric acid : 
 SO 2 + 2H 2 Se = 2H 2 + S.Se 2 . 
 
 In the one case, a sulphide of selenium is formed ; in the other, a sulphide of sulphur. 
 The precipitation of iodine, which takes place on mixing hydriodic with iodic acid, 
 affords a similar instance of the combination of homogenous atoms. The reduction of 
 certain metallic oxides by peroxide of hydrogen, is another striking example of this 
 kind of action. When oxide of silver is thrown into this liquid, water is formed ; the 
 silver is reduced to the metallic state ; and a quantity of oxygen is evolved, equal to 
 twice that which is contained in the oxide of silver. It appears, indeed, as if atoms 
 could not exist in a state of isolation. An atom of an elementary body must unite, 
 either with an atom of another element, or with one of its own kind. 
 
 Similar phenomena are exhibited by the alcohol-radicles : thus, when zinc-ethyl and 
 iodide of methyl are heated together, double decomposition takes place, the products 
 being iodide of zinc and methyl-ethyl : 
 
 C 2 H 5 .Zn + CH 3 .I = Znl + CH 3 .C 2 H 5 ; 
 
 and when zinc-ethyl is heated with iodide of ethyl, a precisely similar action takes 
 place, but attended with formation of free ethyl : 
 
 C 2 H 5 .Zn + C 2 H 5 .I = Znl + C 2 H 5 .C 2 H 5 . 
 
 In the first case, the ethyl separated from the iodine unites with methyl separated from 
 the zinc ; in the second, it unites with another atom of ethyl. The idea of the duality 
 of the molecules of alcohol-radicles in the free state, is likewise in accordance with 
 their observed boiling-points and vapour-densities. (See ALCOHOL-RADICLES, p. 96.) 
 
 Further, elementary bodies frequently act upon others as if their atoms were asso- 
 ciated in binary groups. Thns chlorine acting upon potash forms two compounds, 
 chloride and hypochlorite of potassium : 
 
 KKO -i- C1C1 = C1K + C1KO ; 
 
858 CHEMICAL AFFINITY. 
 
 just as chloride of cyanogen would form chloride and cyanate of potassium. The 
 quantity of chlorine which acts upon an atom of potash, is not 1 at. = 35 '5, but 
 2 at. = 70. Similarly, when metallic sulphides oxidise in the air, both the metal and 
 the sulphur enter into combination with oxygen. Sulphur acting upon potash forms a 
 sulphide and a hyposulphite. Lastly, when zinc-ethyl is exposed to the action of 
 chlorine, iodine, &c., these elements unite separately with the zinc and with the ethyl, 
 thus: 
 
 C 2 H 5 Zn + C1C1 = CPEPCl + ZnCL 
 
 From these considerations it appears that double decomposition, which is generally 
 understood as an action between four elements or groups of elements, may likewise be 
 supposed to take place in cases where only three elements or groups come into play. 
 In like manner we may regard as double decompositions even those reactions which 
 are commonly viewed as the simple combination or separation of two elements, or as 
 the substitution of one element for another. Thus when potassium burns in chlorine 
 gas, the reaction may be supposed to take place between two atoms of chlorine and 
 two atoms of potassium : 
 
 KK + C1C1 = KC1 + KC1. 
 
 Again, the decomposition of cyanide of mercury by heat may be represented thus : 
 CyHg.CyHg = CyCy + HgHg. 
 
 The simple replacement of one element by another may also be regarded as a double 
 decomposition, by supposing the formation of an intermediate compound. Thus the 
 action of zinc upon hydrochloric acid may be supposed to consist of two stages : 
 
 ZnZn + HC1 = ZnH + ZnCl, 
 and ZnH + HC1 = ZnCl + HH. 
 
 It is true that the formation of the intermediate compound, the hydride of zinc, can- 
 not be actually demonstrated in this case, because it is decomposed as fast as it is formed ; 
 but in other cases, the two stages of the action can be distinctly traced. Thus, it is 
 well known that hydrochloric acid does not dissolve copper ; but an alloy of zinc and 
 copper. Cu Zn, dissolves in it readily, with evolution of hydrogen. Here it may be 
 supposed that the first products are chloride of zinc and hydride of copper, a known 
 compound : 
 
 Cu'Zn + HC1 = Cu 2 H + ZnCl; 
 
 and that the hydride is afterwards acted upon by the acid in the manner already ex 
 plained. Again, when zinc and iodide of ethyl are heated together in a sealed tube, 
 iodide of zinc and zinc-ethyl are obtained, thus : 
 
 ZnZn + (C 2 H).I = Znl + Zn(C 2 H 5 ) ; 
 
 and the zinc-ethyl, when heated with excess of iodide of ethyl, yields iodide of zinc 
 and free ethyl (p. 857). 
 
 It thus appears that all well understood cases of chemical action may be referred to 
 one type, namely, that of an interchange of elements between two previously existing 
 compounds. 
 
 d. The transformation of a compound is brought about by a substance which either 
 remains unaltered, or at all events does not enter into combination with either of the 
 elements of the compound. This obscure mode of action, usually called Catalysis, or 
 Contact-action, is chiefly observed in the transformations of organic compounds, such as 
 the conversion of sugar into alcohol and carbonic acid, and of alcohol into acetic acid 
 tinder the influence of yeast; of starch into dextrin and sugar by the action of diastase ; 
 the conversion of urea into carbonate of ammonium, by contact with animal mucus, &c. 
 The terms Catalysis and Contact-action explain nothing, but as mere names they 
 are sometimes convenient. Many decompositions formerly spoken of as catalytic, are 
 now regarded as double decompositions, dependent on the polarity of homogeneous 
 atoms (p. 857). 
 
 Magnitude or Strength of Chemical Affinity. 
 
 That the power which causes bodies to unite is exerted with various degrees of 
 intensity, is evident from the whole range of chemical phenomena. Chlorine certainly 
 unites with hydrogen more readily than with nitrogen, and the elements of hydro- 
 chloric acid are held together with far greater force than those of chloride of nitrogen. 
 If zinc displaces copper from its solution in hydrochloric acid, and copper cannot dis- 
 place zinc from such a solution, we cannot resist the conclusion that the affinity of 
 zinc for chlorine in solution is greater than that of copper. But does this show that 
 the former of these affinities is intrinsically and under all circumstances greater than 
 
CHEMICAL AFFINITY. 859 
 
 the latter ? or may not the relative solubilities of chloride of zinc and chloride of 
 copper, or the cohesion of the metals themselves, have something to do with the result? 
 Or to state the question generally, does each element possess for every other a dis- 
 tinct and specific affinity or combining power, which is always the same, and liable 
 only to be modified in its results by the circumstances under which the bodies are 
 placed, or is the affinity between each pair of elements itself a variable quantity 
 dependent on pressure, temperature, solubility, volatility, the presence of other 
 bodies, &c. &c. ? The older chemists answered the first part of this question in the 
 affirmative. When they found a body A expelling another B from its union with C, 
 they concluded that C had for A a greater affinity than for B. 
 
 On this principle they formed what were called Tables or Columns of Affinity, of 
 which the following may be taken as specimens, the several substances in each being 
 disposed in the order of their supposed affinity for the body at the head of the 
 column : 
 
 Sulphur: 0; K and the other alkali-metals; Zn; Fe; Sn; Cu; Cl; H; C; Pbj 
 Bi; Sb; Hg; Ag; Pt; Cu 4 S; MoS; Au. 
 
 Sulphuric acid: Ba 2 O;Sr 2 0; K 2 0; Na 2 ; Li 2 (?); Ca 2 ; Mg 2 ; Pb 2 ; NH S ; 
 Fe 2 0; Zn 2 0; Ni 2 : Co 2 ; Cu 2 ; A1 4 3 ; Fe 4 Q 3 . 
 Metals: 0; F; Cl ; Br ; I; Se; P; H. 
 
 A very slight acquaintance with chemical phenomena is, however, sufficient to show 
 that these so-called Tables of Affinity are merely tables of the order of decomposition 
 under particular circumstances, and that the relative affinity of one body for two others 
 is liable to change from a great variety of circumstances, sometimes even to be re- 
 versed. Thus, iron at a red heat decomposes vapour of water, abstracting the oxygen 
 and setting the hydrogen free, whence it might be inferred that the affinity of oxygen 
 for iron is greater than for hydrogen ; but if hydrogen gas be passed over red-hot 
 oxide of iron, water is formed and iron set free, indicating an exactly opposite order 
 of affinities. In like manner, potassium heated in an atmosphere of carbonic anhydride, 
 becomes oxidised and sets carbon free ; and on the other hand, charcoal strongly 
 heated with potash, abstracts the oxygen and sets potassium free. Carbonic anhy- 
 dride precipitates silica from a solution of silicate of sodium, and on the other hand 
 silica heated with carbonate of sodium, forms silicate of sodium, and liberates carbonic 
 anhydride ; and similarly in numerous other cases. . 
 
 We must then look to other circumstances besides intrinsic force of affinity to de- 
 termine whether a particular reaction will take place or not. The most important 
 of these circumstances are : 
 
 1. The elasticity or the cohesion of one of the resulting compounds, and its con- 
 sequent tendency to assume the gaseous or solid state, and thus to remove itself from 
 the sphere of action. 
 
 The examples just mentioned afford striking illustrations of the influence of vola- 
 tility in determining chemical decomposition. The tendency of the resulting gas or 
 vapour to diffuse itself through the surrounding atmosphere, doubtless contributes 
 greatly to the result ; thus, when aqueous vapour is passed over red-hot iron, the hy- 
 drogen set free by the decomposition of the water is carried forward by the current 
 of aqueous vapour, and the iron is left free to act upon a fresh portion. The influence 
 of cohesion is clearly seen in precipitations. It is, indeed, a general law that if the 
 solutions of two salts are mixed, and an insoluble compound can be formed from any of 
 their elements, that compound is sure to be produced and to separate from -the liquid. 
 Hence the order of decomposition is frequently reversed by the nature of the solvent. 
 Aqueous acetic acid decomposes carbonate of potassium, eliminating carbonic acid; 
 but if the resulting acetate of potassium be dissolved in alcohol, and carbonic acid 
 gas passed through the solution, carbonate of potassium is precipitated and acetic acid 
 passes into solution as acetic ether. A strong solution of caustic potash decomposes 
 carbonate of calcium, forming carbonate of potassium, and leaving lime undissolved ; 
 but a solution of 1 pt. carbonate of potassium in 10 pts. of water, is decomposed by 
 agitation with lime, yielding caustic potash and carbonate of calcium. A weak 
 solution of sulphurous acid dissolves iodine, forming hydriodic and sulphuric acids, 
 H 2 S0 3 + P + H 2 = 2HI + H 2 S0 4 ; but if the quantity of water in the solution be 
 diminished by evaporation, sulphurous anhydride is evolved and hydriodic acid con- 
 taining iodine remains behind, H-SO 4 + 2HI = I 2 + SO 8 + 2H 2 0. 
 
 2. The relative quantities of the acting substances. That the relative degrees 
 of affinity of a body for a number of others to which it is simultaneously presented 
 are greatly modified by their relative masses, was first pointed out by Berthollet. 
 The law laid down by that philosopher respecting the action of masses, is this : A 
 body to which two different substances capable of acting on it chemically, are presented 
 in different proportions, divides itsdf between them in the ratio of the products of their 
 
860 
 
 CHEMICAL AFFINITY. 
 
 respective masses, and the absolute strengths of their affinities for the first body. Thus, 
 if \ve denote by A and B the masses of the two bodies which are present in excess, by 
 o and )8 the coefficients of their absolute affinities for the body C; and by a and b 
 the quantities of A and B which actually combine with C, the law just stated will be 
 expressed by the proportion : 
 
 a : b = aA : ftB. 
 
 If this view be correct, any alteration, however small, in the relative quantities of A 
 and B, must produce a corresponding alteration in the relative quantities of the two 
 which unite with C. That this is not the case under all circumstances, is shown by 
 the following experiments of Bunsen and of Debus. 
 
 Bunsen's experiments (Ann. Ch. Pharm. Ixxxv. 137), which were made in such a 
 manner that all the phenomena of combination concerned in them took place simulta- 
 neously, lead to the following remarkable laws : 
 
 1. When two or more bodies, BB' . . . are presented in excess to the body A, 
 under circumstances favourable to their combination with it, the body A always selects 
 of the bodies BB' . . . quantities which stand to one another in a simple atomic 
 relation, so that for 1, 2, 3 ... atoms of the one compound, there are always formed 
 1, 2, 3 ... atoms of the other; and if in this manner there is formed an atom of the 
 compound A B', in conjunction with an atom of AB, the mass of the body B may be 
 increased relatively to that of B', up to a certain limit, without producing any altera- 
 tion in the atomic proportion. 
 
 When carbonic oxide and hydrogen are exploded with a quantity of oxygen not 
 sufficient to burn them completely, the oxygen divides itself between the two gases in 
 such a manner that the quantities of carbonic anhydride and water produced stand to 
 one another in a simple atomic proportion. The results of Bunsen's experiments are 
 given in the following table, the numbers in which denote volumes : 
 
 Composition 
 
 of Gaseous Mixture. 
 
 Quantities of CO and H consumed 
 by Detonation. 
 
 Ratio of 
 CO:H. 
 
 72-57 CO . 
 69-93 
 36-70 
 40-12 
 
 18-29 H 
 26-71 
 42-17 
 47-15 
 
 . 9-14 
 . 13-36 
 .,21-13 
 . 12-73 
 
 12-18 CO 
 
 13-06 
 10-79 
 4-97 
 
 6-10 H 
 . 13-66 
 . 31-47 
 . 20-49 
 
 2 1 
 1 1 
 1 3 
 
 1 4 
 
 The results were the same whether the explosion took place in the dark, in diffused 
 daylight, or in sunshine ; and were not affected by the pressure to which the gaseous 
 mixture was subjected. 
 
 The proportions of hydrogen and carbonic oxide consumed in these several experi- 
 ments, correspond with the composition of five hydrates of carbonic anhydride, contain- 
 ing, respectively: 
 
 H 2 0.2C0 2 ; H 2 O.C0 2 ; 2H 2 O.C0 2 ; 3H 2 O.C0 2 ; 4H 2 O.C0 2 ; 
 
 but the results cannot be attributed to the actual formation of these hydrates, inas- 
 much as hydrates of acids containing several atoms of water are incapable of existing 
 at high temperatures. 
 
 2. When a body, A, exerts a redwing action on a compound, BC, present in excess, 
 so that A and B combine together and C is set free ; then, if C can, in its turn, exert 
 a reducing action on the newly-formed compound, AB, the final result of the action 
 is, that the reduced portion of BC is to the unreduced portion in a simple atomic 
 proportion. 
 
 In this case, also, the mass of the one constituent may, without altering the existing 
 atomic relation, be increased to a certain limit, above which, that relation undergoes 
 changes by definite steps, but always in the proportion of simple rational numbers. 
 
 When vapour of water is passed over red-hot charcoal, the carbon is oxidised and 
 hydrogen is separated ; but the process does not go on so far as the complete formation 
 of carbonic anhydride, but stops at the point at which 1 vol. carbonic anhydride and 
 
 2 vol. carbonic oxide are formed to every 4 vol. of hydrogen. 
 
 In the imperfect combustion of cyanogen the gaseous mixture being so far diluted 
 that it will but just explode, in order that the temperature may not rise too high, and 
 the result be consequently vitiated by the partial oxidation of the nitrogen carbonic 
 anhydride and carbonic oxide are formed, and nitrogen set free, likewise in simple 
 atomic proportion. A mixture of 18'05 vol. cyanogen, 28'87 oxygen, and 53*08 
 nitrogen, gave, by detonation, 2 vol. carbonic oxide, and 4 vol. carbonic anhydride to 
 
 3 vol. nitrogen. 
 
CHEMICAL AFFINITY. 861 
 
 In fLe combustion of a mixture of carbonic anhydride, hydrogen, and oxygen, in 
 which the carbonic anhydride is exposed at the same time to the reducing action of the 
 hydrogen and the oxidising action of the oxygen, the reduced portion of the carbonic 
 anhydride is likewise found to bear to the unreduced portion. a simple atomic relation. 
 In the combustion of a mixture of 8'52 carbonic anhydride, 70'33 hydrogen, and 2T15 
 oxygen, the resulting carbonic oxide was to the reduced carbonic anhydride in the 
 ratio of 3 : 2. After the combustion of a mixture of 4'41 vol. carbonic oxide, 2'96 
 carbonic anhydride, 68*37 hydrogen, and 24- L 6 oxygen, the volume of the carbonic 
 oxide converted into carbonic anhydride by oxidation, was to that of the residual 
 carbonic oxide as 1 : 3. 
 
 That these remarkable laws had not been previously observed, is attributed by 
 Bunsen to the fact that they hold good only when the phenomena of combination, 
 which are regulated by them, take place simultaneously : for, even if a body A were 
 originally to select for combination from the bodies B and C, quantities bearing to 
 one another a simple atomic relation, but the combination of A and B were to take place 
 in a shorter time than that of A and (7, it would follow of necessity, that during the 
 whole of the process, the ratio of B to C, and therefore, also the atomic relations of 
 the associated compounds, would change, so that the observed proportion would be no 
 longer definite. The same result must follow if the bodies which are combining side 
 by side are not homogeneously mixed in the beginning. 
 
 With regard to the bearing of these results on Berthollet's law, it might be objected 
 that, in some of the experiments, as in the combustion of a mixture of carbonic oxide, 
 hydrogen, and oxygen, one of the products, viz. the water, is removed from the sphere 
 of action by condensation, and that the circumstances are therefore similar to the 
 removal of an insoluble product by precipitation. It is scarcely conceivable, however, 
 that a reverse action would take place, even if the gaseous mixture were to remain 
 at the temperature which exists during the combustion. Moreover, in the decompo- 
 sition of vapour of water by red-hot charcoal, the whole of the products remain in the 
 gaseous state. 
 
 Debus (Ann. Ch. Pharm. Ixxvx. 103; Ixxxvi. 156; Ixxxvii. 238), has obtained 
 results similar to those of Bunsen, by precipitating mixtures of lime and baryta- water 
 with aqueous carbonic acid, or mixtures of chloride of barium and chloride of cal- 
 cium with carbonate of sodium. A small quantity of a very dilute solution of car- 
 bonate of sodium added to a liquid containing 5 pts. of chloride of barium to 1 pt. of 
 chloride of calcium, threw down nearly pure carbonate of calcium ; but when the pro- 
 portion of the chloride of barium in the mixture was 5 ~1 times as great as that of the 
 chloride of calcium, 2*3 pts. of the former were decomposed to 1 pt. of the latter. 
 Hence it appears that, in this reaction also, limits exist at which the ratio of the 
 affinities undergoes a sudden change. In these experiments, however, the products 
 are immediately removed from the sphere of action, and the results are therefore not 
 comparable with those which are obtained when all the substances present remain 
 mixed and free to act upon each other. 
 
 The latter condition is most completely fulfilled in the mutual actions of liquid 
 compounds, such as solutions of salts, when all the possible products of their mutual 
 actions are likewise soluble; as, for example, when nitrate of sodium in solution is mixed 
 with sulphate of copper. The question to be solved in snch cases is this. Suppose two 
 salts AB, CD, the elements of which can form only soluble products by their mutxial 
 interchange, to be mixed together in solution. Will these elements, according to their 
 relative affinities, either remain in their original state of combination, as AB and CD, 
 or pass completely into the new arrangement AD and C B ? or will each of the two 
 acids divide itself between each of the two bases, producing the four compounds AB, 
 AD, BC, BD ? and, if so, in what manner will the relative quantities of these four 
 compounds be affected by the original quantities of the two salts ? Do the amounts of 
 AD and CB, produced by the reaction, increase progressively with the regular increase 
 of AB, as required by Berthollet's theory ? or do sudden transitions occur, like those 
 observed in the experiments of Bunsen and Debus ? 
 
 The solution of this question is attended with considerable difficulty. For when two 
 salts in solution are mixed, and nothing separates out, it is by no means easy to as- 
 certain what changes may have taken place in the liquid. The ordinary methods of 
 ascertaining the composition of the mixture, such as concentration, or precipitation by 
 reagents, are inadmissible, because any such treatment immediately alters the mutual 
 relation of the substances present. In some cases, however, the mixture of two salts 
 is attended with a decided change of colour, without any separation of either of the 
 constituents, and such alterations of colour may afford indications of the changes which 
 take place in the arrangement of the molecules. This method has been employed by 
 Dr. Gladstone (Phil. Trans. 1855, 179; Chem.Soc. Q,u. J. ix. 54), who has carefully 
 examined the changes of colour attending the mixture of a great variety of salts, and 
 
862 
 
 CHEMICAL AFFINITY. 
 
 applied the results to the determination of the effect of mass in influencing chemical 
 action. 
 
 Dr. Gladstone's principal experiments were made with the blood-red sulphocyauate 
 of iron, which is formed on adding sulphocyanic acid or any soluble sulphocyanate 
 to a solution of a ferric salt. On mixing known quantities of different ferric salts with 
 known quantities of different sulphocyanates, it was found that the iron was never 
 completely converted into the red salt ; that the amount of it so converted depended 
 on the nature both of the acid combined with the ferric oxide, and of the base com- 
 bined with the sulphocyanogen ; and that it mattered not how the bases and acids had 
 been combined previous to their mixture, so long as the same quantities were brought 
 together in solution. The effect of mass was tried by mixing equivalent proportions 
 of ferric salts and sulphocyanates, and then adding known amounts of one or the other 
 compound. It was found that, in either case, the amount of the red salt was increased, 
 and in a regular progression according to the quantity added. When sulphocyanate 
 of potassium was mixed in various proportions with ferric nitrate, chloride, or sulphate, 
 the rate of variation appeared to be the same, but with hydrosulphocyanic acid it was 
 different. The deepest colour was produced when ferric nitrate was mixed with sulpho- 
 cyanate of potassium ; but even on mixing 1 at. of the former with 3 at. of the latter, 
 only 0-194 at. of the red sulphocyanate of iron was formed; and even when 375 at. 
 of sulphocyanate of potassium had been added, there was still a recognisable amount 
 of ferric nitrate undecomposed. The results of a series of experiments with ferric 
 nitrate and sulphocyanate of potassium are given in the following table : 
 
 Ferric 
 Nitrate. 
 
 Sulphocyanate of 
 Potassium. 
 
 Red Salt 
 produced. 
 
 Ferric 
 Nitrate. 
 
 Sulphocyanate of 
 Potassium. 
 
 Red Salt 
 produced. 
 
 1 equiv. 
 
 3 atoms. 
 
 88 
 
 atom. 
 
 63 atoms. 
 
 356 
 
 
 6 
 
 127 
 
 
 99 
 
 419 
 
 
 9-6 
 
 156 
 
 
 135 ' 
 
 487 
 
 
 12-6 
 
 176 
 
 ' 
 
 189 , 
 
 508 
 
 
 lfi-2 
 
 195 
 
 
 243 
 
 539 
 
 
 l'J-2 
 
 213 
 
 
 297 , 
 
 560 
 
 
 282 
 
 266 
 
 
 375 
 
 587 
 
 
 46'2 
 
 318 
 
 
 
 
 The addition of a colourless salt reduced the colour of a solution of ferric sulpho- 
 cyanate, the reduction increasing in a regularly progressive ratio, according to the 
 mass of the colourless salt. 
 
 Similar results were obtained with other ferric salts, viz. with the black gallate, the 
 red meconate and pyromeconate, the blue solution of Prussian blue in oxalic acid, &c., 
 and likewise with the coloured salts of other metals, e. g. the scarlet bromide of gold, 
 the red iodide of platinum, the blue sulphate of copper, when treated with different 
 chlorides, &c. 
 
 The amount of fluorescence exhibited by a solution of acid sulphate of quinine was 
 found to be affected by the mixture of a chloride, bromide, or iodide, according to the 
 nature and mass of the salt added ; and the addition of sulphuric, phosphoric, nitric, 
 and other acids was found to produce a fluorescence in solutions of hydrochlorate of 
 quinine, or of sulphate which had been rendered non-fluorescent by the addition of hydro- 
 chloric acid. Solutions of horse-chestnut bark, and of tincture of thorn-apple, yielded 
 similar results. 
 
 The conclusions to be drawn from Gladstone's experiments, are as follows : 
 
 "When two or more binary compounds are mixed under such circumstances that all 
 the resulting compounds are free to act and react, each acid element enters into com- 
 bination with each basylous element in certain constant proportions, which are inde- 
 pendent of the manner in which the different elements are primarily arranged, and are 
 not merely the resultant of the various strengths of affinity of the several substances 
 for each other, but are dependent also on the mass of each of the substances present in 
 the mixture. All deductions respecting the arrangement of substances in solution, 
 drawn from such empirical rules as that the strongest acid combines with the strongest 
 base, must therefore be looked upon as doubtful. An alteration in the mass of any of 
 the binary compounds present, alters the amount of every one of the other binary 
 compounds, and that in a regularly progressive ratio, sudden transitions occurring only 
 where a substance is present, which is capable of combining with another in more 
 than one proportion. This equilibrium of affinities arranges itself in most cases in an 
 inappreciably short time; but, in certain instances, the elements do not attain their 
 final state of combination for hours. 
 
 Totally different phenomena present themselves where precipitation, volatilisation, 
 crystallisation, and perhaps other actions occur, simply because one of the substances 
 
CHEMICAL AFFINITY. 863 
 
 is thus removed from the field of action, and the equilibrium, which was at first 
 established, is thus destroyed. 
 
 The reciprocal action of salts in solution has also been examined by Mai a gut i 
 (Ann. Ch. Phys. [3] xxxvii. 198 ; and by Margueritte (Compt. rend, xxxviii. 305), 
 both of whom conclude that each base divides itself between the several acids. Mala- 
 guti concludes from his experiments that, in the mutual action of two salts, if nothing 
 separates from the liquid, the decomposition is most complete when the strongest acid 
 and the strongest base are not originally united in the same salt, and that two experi- 
 ments of this kind, made in opposite ways, must lead to the same final result ; that, 
 for example, when 1 at. of acetate of barium is added to 1 at. of nitrate of lead, the 
 quantities of nitrate of barium and nitrate of lead ultimately present in the liquid are 
 the same as when 1 at. nitrate of barium is mixed with 1 at. acetate of lead. 
 
 Margueritte finds that two salts in solution decompose each other, even when one of 
 them is already the least soluble of the four salts that may be produced from the acids 
 and bases present. Thus, a saturated solution of chlorate of potassium to which 
 chloride of sodium is added, becomes capable of dissolving an additional quantity of 
 chlorate of potassium, showing that a portion of the chlorate has been decomposed 
 and a more soluble salt formed. 
 
 There are, however, certain well known phenomena, which show that this distri- 
 bution of acids and bases in solution does not always take place. Boric acid colours 
 litmus wine-red; sulphuric acid turns it bright red. Now if sulphuric acid be gra- 
 dually added to a warm solution of borate of sodium in water which has been coloured 
 blue with litmus, the liquid at first remains blue, because a combination of soda with 
 excess of boric acid is produced ; on the addition of more sulphuric acid, boric acid is 
 set free, and colours the liquid wine-red ; and not till all the soda has entered into 
 combination with the sulphuric acid does a further addition of that acid give the liquid 
 a bright red colour ; biit if sulphuric acid were present at the commencement of the 
 action, either in the free state or combined with sulphate of sodium in the form of an 
 acid salt, the bright red colour would appear at once. From the same cause, a solution 
 of sulphate of potassium or sodium to which boric acid has been added, colours litmus 
 only wine-red ; but the addition of ^~ of sulphuric acid immediately produces the 
 bright red tint. Hence boric acid cloes not take soda from sulphuric acid or set that 
 acid free. Sulphydric acid and carbonic acid exhibit similar relations towards sul- 
 phuric acid. Tincture of litmus is instantly bleached by chlorine- water, but not till 
 after several days by aqueous solution of iodine : now, a solution of chloride of sodium 
 mixed with iodine should, according to Berthollet, produce a mixture containing 
 chloride of sodium with excess of chlorine, and iodide of sodium with excess of 
 iodine. But the orange-yellow mixture colours litmus green (from the yellow of the 
 solution and the blue of the tincture) : and a very small quantity of chlorine-water 
 immediately changes this green colour into the orange-yellow of the solution of iodine : 
 this shows that no chlorine had been set free by the iodine. Ferric phosphate is 
 soluble in hydrochloric acid, but not in acetic acid. From its solution in hydrochloric 
 acid it is completely precipitated by acetate of potassium. Now if the potash had 
 been divided between the hydrochloric and acetic acids, part of the hydrochloric acid 
 would have remained free, and would have held some of the phosphate of iron in 
 solution. (Gm. i. 153.) 
 
 The decomposition of soluble by insoluble salts, affords a striking instance of the 
 tendency of atoms to interchange, and of the influence of mass on chemical action. 
 According to H. Eose (Pogg. Ann. xciv. 481 ; xcv. 96, 284), sulphate of barium is 
 completely decomposed by boiling with solutions of alkaline carbonates, provided that 
 each atom of sulphate of barium is acted upon by at least 15 at. of the alkaline 
 carbonate. When 1 at. of sulphate of barium is boiled with only 1 at. of carbonate of 
 potassium, only | of it is decomposed, and only by boiling with 1 at. of carbonate 
 of sodium, further decomposition being prevented by the presence of the alkaline sul- 
 phate already formed. If, however, the liquid be decanted after a while, the residue 
 boiled with a fresh portion of the alkaline carbonate, and these operations repeated 
 several times, complete decomposition is effected. Carbonate of barium is converted 
 into sulphate by the action of an aqueous solution of sulphate of potassium or sodium, 
 even at ordinary temperatures. Solution of carbonate of ammonium does not decom- 
 pose sulphate of barium either at ordinary or at higher temperatures ; carbonate of 
 barium is not decomposed by sulphate of ammonium at ordinary temperatures, but 
 easily on boiling. Sulphate of barium is not decomposed by boiling with caustic 
 potash-solution, provided the carbonic acid of the air be excluded ; but by fusion with 
 hydrate of potassium it is decomposed, with formation of carbonate of barium, because 
 the carbonic acid of the air cannot then be completely excluded. Hydrochloric and 
 nitric acids, leftin contact at ordinary temperatures with sulphate of barium, either crys- 
 tallised or precipitated, dissolve only traces of it ; at the boiling heat, a somewhat 
 
864 CHEMICAL AFFINITY. 
 
 larger quantity is dissolved, and the solution forms a cloud, both with a dilute solution 
 of chloride of barium and with dilute sulphuric acid. Sulphate of strontium is dissolved 
 by hydrochloric acid at ordinary temperatures, sufficiently to form a slight precipitate 
 with dilute sulphuric acid, and with chloride of strontium. Sulphate of calcium 
 treated with hydrochloric acid, either cold or boiling, yields a liquid in which a preci- 
 pitate is formed, after a while, by dilute sulphuric acid, but not by chloride of calcium. 
 
 Sulphate of strontium and sulphate of calcium are completely decomposed by solutions 
 of the neutral and acid carbonates of the alkali-metals at ordinary temperatures, and 
 more quickly on boiling, even if considerable quantities of an alkaline sulphate are added 
 to the solution : the decomposition is also eifected by carbonate of ammonia, even at 
 ordinary temperatures. The carbonates of strontium and calcium are not decomposed 
 by solutions of the sulphates of potassium or sodium at any temperature ; sulphate 
 of ammonium does not decompose them at ordinary temperatures, but readily with the 
 aid of heat. 
 
 Sulphate of lead is completely converted into carbonate by solutions of the neutral 
 and acid carbonates of the alkali-metals, even at ordinary temperatures, the neutral 
 carbonates, but not the acid carbonates, then dissolving small quantities of oxide of 
 lead. Carbonate of lead is not decomposed by solutions of the alkaline sulphates, 
 either at ordinary temperatures or on boiling. 
 
 Chromate of barium is decomposed at ordinary temperatures by solutions of the 
 neutral carbonates of the alkali-metals, and much more easily by boiling with ex- 
 cess of an acid carbonate of alkali-metal. When equivalent quantities of the chromate 
 of barium and carbonate of sodium are boiled with water, of the whole is decom- 
 posed ; when the same quantities of the salts are fused together, and the mass treated 
 with water, only i of the barium-salt is decomposed. Carbonate of barium is com- 
 pletely converted into chromate by digestion with the solution of an alkaline mono- 
 chromate ; and the decomposition of chromate of barium by neutral alkaline carbonates, 
 even at the boiling heat, is completely prevented by the presence of a certain quantity 
 of an alkaline monochromate. 
 
 Selenate of barium is easily and completely decomposed by solutions of alkaline 
 carbonates, even at ordinary temperatures : this salt is somewhat soluble in water, and 
 more readily in dilute acids. 
 
 Oxalate of calcium is decomposed by alkaline carbonates, even at ordinary tempe- 
 ratures ; but to effect complete decomposition, the liquid must be frequently decanted 
 and renewed. The decomposition takes place rapidly at the boiling heat ; but in all 
 cases it is completely prevented by the presence of a certain quantity of a neutral 
 alkaline oxalate. When the salts are mixed in equivalent proportions, -^ of the oxalate 
 of calcium are decomposed at ordinary temperatures, and f on boiling. Carbonate of cal- 
 cium is partially converted into oxalate by the action of a solution of neutral oxalate 
 of potassium at ordinary temperatures, and more quickly on boiling ; but the decom- 
 position is never complete, even when the liquid is frequently decanted and renewed. 
 Oxalate of lead is completely converted into carbonate at ordinary temperatures by 
 the solution of an alkaline carbonate, a small portion of the carbonate of lead dissolving 
 in the liquid. (R o a e.) 
 
 The preceding experiments exhibit in a remarkable manner the influence of difference 
 of solubility in determining the order of decomposition. Sulphate of barium is lesa 
 soluble than the carbonate, and, accordingly, carbonate of barium is more readily de- 
 composed by alkaline sulphates than the sulphate by alkaline carbonates. Precisely the 
 contrary relations are exhibited by the sulphates and carbonates of strontium * and 
 calcium, both as regards solubility and order of decomposition. On the other hand, 
 oxalate of calcium is less soluble than the carbonate, and yet its decomposition by 
 alkaline carbonates takes place more easily than the opposite reaction ; in this case, 
 the order of decomposition appears rather to be dftermined, as in Malaguti's experi- 
 ments (p. 862), by the tendency of the strongest acid to unite with the strongest base. 
 
 The effect of a soluble sulphate, &c. in arresting the decomposition of the correspond- 
 ing insoluble salts by alkaline carbonates, is evidently due to its tendency to produce 
 the reverse action : hence the acceleration produced by decanting and renewing the 
 liquid. Some insoluble salts, however, phosphate of calcium for example, are never com- 
 pletely decomposed, even by this treatment. (See also Malaguti, Ann. Ch. Phys. [3] 
 li. 328.) 
 
 Theories of Chemical Action. 
 
 Chemical combination was in early times attributed to the general principle of 
 Hippocrates that "like assorts with like:" hence the word Affinity, which seems to 
 have been first employed by Barchhusen. Becher assumed, in accordance with this 
 dogma, that when two bodies are capable of combining, they must contain a common 
 
 * According to Fresenius, carbouate of strontium dissolves in 11,862 parts, and sulphate of strontium 
 in 6895 parts of water. 
 
CHEMICAL AFFINITY. 865 
 
 principle. Others, among whom was Lemery, supposed that solvents are furnished 
 with a number of sharp points, by means of which they are more or less adapted to 
 insinuate themselves into the pores of solid bodies and combine with them. 
 
 Dismissing these crude notions, we have to consider four distinct hypotheses which 
 have been proposed to account for the phenomena of chemical action. 
 
 1. Chemical combinations are produced by universal attraction. 
 
 Newton was the first who referred chemical combination to universal attraction, 
 though he did not regard the attraction between ultimate particles as exactly the 
 same with that which acts between the great bodies of the universe. 
 
 Berthollet also regarded chemical combination as a manifestation of the force of 
 universal attraction, exhibiting peculiar characteristics, because it is exerted, not on 
 masses, but on molecules placed at extremely small distances from each other. Being 
 unacquainted with the laws of combination in definite proportions, he supposed that 
 bodies, by virtue of their affinity, are essentially capable of uniting in all proportions, 
 and attributed what he considered the apparent exceptions to the law, entirely to the 
 influence of cohesion and elasticity. That these causes exert considerable influence on 
 chemical combination, is sufficiently evident from the phenomena already discussed ; 
 but to suppose that combination in definite proportion is absolutely dependent upon 
 them, would be inconsistent with our present knowledge of the constitution of chemical 
 compounds ; indeed, the single fact that chlorine and hydrogen unite in one proportion 
 only, and form hydrochloric acid gas, without any condensation or expansion, is quite 
 sufficient to show the untenability of such a supposition. 
 
 2. Chemical combinations are produced by a peculiar power called Affi nity, distinct 
 from all others. This hypothesis may be reserved for discussion after it has been 
 shown that all the known powers of nature are insufficient to account for the pheno- 
 mena of chemical action. 
 
 3. The union of heterogcnous atoms is the result of Electrical attraction. 
 Numerous theories of this kind have been proposed, among others by Davy, Dumas, 
 
 Becquerel, Ampere, Grotthuss, Schweigger, Fechner, Berzelius and L. Grmelin. 
 
 Berzelius supposed that "The atom of every substance has two poles, on which the 
 opposite electricities are accumulated in different proportions, according to the nature 
 of the bodies. The atom of many bodies, oxygen for instance, has a large quantity of 
 negative electricity attached to one of its poles, and but a very small quantity of 
 positive electricity at the other ; that of other bodies, potassium for example, has a 
 large quantity of positive electricity at one pole, and a very little negative electricity 
 at the other. Thus the elementary substances are divided into electro-negative and 
 electro-positive. To each element, however, there belongs a particular proportion be- 
 tween the quantities of the two electricities. Oxygen has, of all the electro-negative 
 elements, the greatest quantity of negative electricity at one of its poles, and the smallest 
 quantity of positive electricity at the other, then follows sulphur, then nitrogen, &c., 
 and lastly hydrogen, in which the quantities of the two electricities are nearly equal. 
 Of all electro-positive substances, potassium has the largest quantity of positive and 
 the smallest of negative electricity ; and this inequality continually diminishes in 
 other bodies, till we come to gold, in which the positive electricity predominates but 
 little over the negative so that this element occupies the next place to hydrogen. 
 According to this, the elements succeed one another in the electro-chemical series 
 of 'Berzelius as follows, beginning with the electro-negative. 
 
 " Electro-negative, 0, S, N, F, 01, Br, I, Se, P, As, Cr, V, Mo, W, B, C, Sb, Te, Ta, 
 Ti, Si, H. 
 
 " Electro-positive, Au, Os, Ir, Pt, Rh, Pd, Hg, Ag, Cu, U, Bi, Sn, Pb, Cd, Co, Ni, Fe, 
 Zn, Mn, Ce, Th, Zr, Al, Y, G, Mg, Ca, Sr, Ba, L, Na, K 
 
 " In the combination of an electro-negative with an electro-positive body, the predo- 
 minant negative electricity of the former unites with the predominant positive elec- 
 tricity of the latter. Before, however, combination takes place, the former substance 
 exhibits negative, and the latter positive electricity in the free state ; and the tension 
 of the two electricities continually increases as the bodies approach the temperature 
 at which combination takes place. Hence we have an explanation of electricity by con- 
 tact. At the instant of combination, the negative poles of the atoms of the first body 
 turn themselves towards the positive poles of those of the second ; and since it is only 
 in the fluid state that the atoms possess the mobility necessary for this arrangement, it 
 follows that solid bodies have, generally speaking, no chemical action on one another. 
 The two electricities of these poles now combine and produce heat or fire, whereupon 
 they disappear. In every chemical combination, therefore, a neutralisation of the opposite 
 electricities takes place, by which heat or fire is produced in the same manner as in the 
 discharge of the electrical pile or of lightning, excepting that these last-mentioned 
 phenomena are not accompanied by any chemical combination, at least of ponderable 
 
 VOL. I. 3 K 
 
866 CHEMICAL AFFINITY. 
 
 bodies. Every chemical combination is therefore an electrical phenomenon depend- 
 ing on the electrical polarity of the atoms." 
 
 The main difficulty of this theory is to account for the force by which combined 
 atoms are held together. The heterogeneous atoms unite in consequence of their 
 adhesion to the opposite electricities ; but when these have been neutralised by com.' 
 bination, it might be expected that the atoms would fall asunder and allow themselves 
 to be easily separated by friction and other mechanical forces, which is not the case. 
 This objection to the theory of Berzelius has never been satisfactorily answered. 
 
 Gmelin's theory is as follows: " Ponderable bodies have affinity for one another. 
 The two electricities are substances which likewise possess affinity for each other, and 
 by whose combination in the proportions in which they neutralise each other, heat 
 (fire) is produced. The individual electricities, and likewise heat, have considerable 
 affinity for ponderable substances, and are united to them with greater force and in 
 greater quantity, the more simple these ponderable substances are. Ponderable 
 bodies, according to their nature, have a greater or less excess of positive or negative 
 electricity united with them, in addition to a definite quantity of heat. Thus, oxygen 
 probably contains the greatest quantity of positive, and potassium of negative electri- 
 city. Bodies lying between these two extremes, contain a larger quantity of heat with 
 a smaller excess of one or the other kind of electricity, the proportion of which varies 
 greatly according to their nature. 
 
 " The combination of two ponderable bodies is the result of two forces, viz. the 
 affinity of the ponderable bodies for each other, and the affinity of the electricity 
 which is in excess in the one body for the opposite electricity which predominates in 
 the other. By these two forces, the affinity of the electro-negative body for the 
 positive electricity united with it, and that of the electro-positive body for the negative 
 electricity combined with it, are overcome. The result is heat and the ponderable 
 compound. The latter retains the excess of positive or negative electricity, by which 
 it requires either an electro-negative or electro- positive character, and likewise part of 
 the heat while another portion is set free, and gives rise to the development of heat 
 or fire, by which most chemical combinations are accompanied. When combination 
 takes place between two bodies, both of which contain an excess of the same kind 
 of electricity, e.g. oxygen and sulphur, which contain free positive electricity in 
 different quantities, it is simplest to suppose that the combination is the result 
 merely of the affinity between the two ponderable bodies, that the new compound 
 contains the sum of the excesses of positive electricity, and that the development of 
 heat is a consequence of the inability of the new compound to retain as much heat 
 united with it as was before combined with its constituents." (Gm. i. 154 158.) 
 
 4. Chemical action results from a constant motion among the ultimate particles of 
 bodies, this same movement likewise giving rise to the phenomena of heat, light, 
 and electricity. This is the theory suggested by Williamson (Chem. Soc. Qu. J. 
 vi. 110). The atoms of all compounds, whether similar or dissimilar, are supposed to 
 be continually changing places, the interchange taking place more quickly as the 
 atoms resemble each other more closely. Thus, in a mass of hydrochloric acid, each 
 atom of hydrogen is supposed, not to remain quietly in juxtaposition with the atom of 
 chlorine with which it happens to be first united, but to be continually changing places 
 with other atoms of hydrogen, or, what comes to the same thing, continually becoming 
 associated with other atoms of chlorine. This interchange is not perceptible to the 
 eye, because one molecule of hydrochloric acid is exactly like another. But suppose 
 the hydrochloric acid to be mixed with a solution of sulphate of copper (the com- 
 ponent atoms of which are likewise undergoing a change of place) : the basylous 
 elements, hydrogen and copper, then no longer limit their change of place to the circle 
 of atoms with which they were at first combined, but the hydrogen and copper likewise 
 change places with each other, forming chloride of copper and sulphuric acid. Thus 
 it is that, when two salts are mixed in solution, and nothing separates out in conse- 
 quence of their mutual action, the bases are divided between the acids, and four salts 
 are produced. If, however, the analogous elements of the two compounds are very- 
 dissimilar, and, consequently, interchange but slowly, it may happen that the stronger 
 acid and the stronger base remain almost entirely together, leaving the weaker ones 
 combined with each other. This is strikingly seen in a mixture of sulphuric acid 
 (sulphate of hydrogen) and borate of sodium, which soon becomes almost wholly con- 
 verted into sulphate of sodium and free boracic acid (borate of hydrogen). 
 
 Now, suppose that, instead of sulphate of copper, sulphate of silver is added to the 
 hydrochloric acid. At the first moment, the interchange of elements may be supposed 
 to take place as above, and the four compounds, H*S0 4 , Ag 2 S0 4 , IIC1, and AgCl, to 
 be formed ; but the last being insoluble, is immediately removed by precipitation ; 
 the remaining elements then act upon each other in the same way, and this action 
 goes on till all the chlorine or all the silver is removed in the form of chloride 
 
CHENOCHOLIC ACID CHENOPODIUM. 867 
 
 of silver; if the original compounds are mixed in exactly equivalent proportions, 
 the final result is the formation of only two salts, viz. in this case, ITSQ 4 and AgCl. 
 A similar result is produced when one of the products of the decomposition is volatile 
 at the existing temperature, as when hydrate or carbonate of sodium is boiled with 
 chloride of ammonium. 
 
 If no precipitation or volatilisation takes place, and one of the compounds (hydro- 
 chloric acid) is in excess of the other (sulphate of copper), then, as the atoms of 
 copper in their several interchanges must come in contact with chlorine-atoms more 
 frequently than with S0 4 -atoms, the final result must be the formation of a larger 
 quantity of chloride of copper and of sulphate of hydrogen than if the bodies had been 
 mixed in equivalent proportions, this effect of course increasing as the relative quantity 
 of hydrochloric acid is greater in the original mixture ; and thus we have an explana- 
 tion of the effect of mass in chemical reaction. 
 
 The same theory affords an easy explanation of certain chemical changes otherwise 
 somewhat obscure. Consider, for example, the formation of ether by the action of 
 sulphuric acid upon alcohol, whereby ethyl-sulphuric acid (sulphate of ethyl and 
 hydrogen) is first formed, and afterwards, at a certain temperature, ether and water 
 
 are eliminated (p. 76). When alcohol, TT [0, and sulphuric acid, -g-fSO 4 , are 
 
 mixed together, the interchange between the atoms of ethyl in the former and of 
 hydrogen in the latter gives rise to the formation of ethyl-sulphuric acid and water : 
 
 H n = H 
 
 But the change does not stop here : for the ethyl-sulphuric acid thus produced, meetin 
 with fresh molecules of alcohol, exchanges its ethyl for. the hydrogen of the alcohol 
 producing ether and sulphuric acid : 
 
 C 2 IP) S04 
 H JSO 
 
 The sulphuric acid is thus restored to its original state, and is ready to act upon fresh 
 quantities of alcohol ; so that if alcohol be allowed to run into the mixture in a con- 
 stant stream, the temperature being kept within certain limits (between 130 and 
 140 C.), the process goes on without interruption, ether and water continually distil 
 over, and the same quantity of sulphuric acid suffices for the etherification of an un- 
 limited quantity of alcohol. This is the peculiarity of the process ; it has given rise 
 to a variety of explanations, all more or less unsatisfactory, the discussion of which 
 would be foreign to the present purpose ; it is sufficient to remark that the hypothesis 
 of atomic interchange affords a ready explanation of the chief peculiarity of the re- 
 action, viz. the formation and decomposition of ethyl-sulphuric acid following each 
 other continuously, without any change of temperature or other determining cause. 
 If it be admitted that the atoms of ethyl and hydrogen in the mixture are continually 
 interchanging in all possible ways, this series of alternate actions follows as a neces- 
 sary consequence. 
 
 The idea of atomic motion is in accords nee with physical as well as chemical phe- 
 nomena. To suppose that rest, rather than motion, is the normal state of the particles 
 of matter, is at variance with all that we know of the effects of light, heat, and elec- 
 tricity. In the theory of heat, the particles of bodies are supposed to be affected with 
 progressive, as well as with rotatory and vibratory movements ; and this same hypo- 
 thesis of progressive movement, which of course implies change of relative position 
 amongst the particles, affords, as already stated, an easy explanation of certain chemical 
 reactions otherwise difficult to understand. 
 
 CHEiroCHOXiXC ACID. C 27 H 54 4 . An acid obtained by boiling tauro- 
 chenocholic acid, the sulphuretted acid of goose-bile, with baryta- water, and decom- 
 posing the resulting barium-salt with hydrochloric acid. It is insoluble in water, but 
 soluble in alcohol and ether, whence it separates as an amorphous mass. The solutions 
 have an acid reaction, and give the characteristic blood-red colour with sugar and 
 sulphuric acid. It is insoluble in cold potash, but when heated with it, forms a salt 
 which, when freed from excess of potash, dissolves readily in water and in alcohol. 
 The barium-salt, consists of C- 7 H 53 Ba0 4 . (Heintz and Wislicenus, Pogg. Ann. 
 cviiii. 547.) 
 
 CHEUOCOPROLITE. An impure iron sinter, containing a little silver and 
 arsenate of cobalt. It is a product of decomposition, not a distinct mineral. 
 
 CHENOPODIU1VT. The herb of Chenopodium ambrosio'ides yields by distillation, 
 a pure greenish -yellow volatile oil (about 1| oz. from 10 Ib.) having an aromatic and 
 
 3K 2 
 
868 
 
 CHERT CHIASTOLITE. 
 
 cooling taste (II. Becker, Zeitschr. Pliarm. 1854, p. 8). According to Hirzel (ibid.) 
 this oil, dehydrated by chloride of calcium and rectified, yields a colourless distillate 
 boiling at 179 to 181 C. 
 
 Chenopodium maritimum. The ash of this plant, growing on a strip of land re- 
 claimed from the sea, has been analysed by Harms (Ann. Ch. Pharm. xciv. 247) with 
 the following results : a. Flowers and young shoots, b. Stems. 
 
 K 2 O Na 2 Ca 2 Mg 2 Fe 4 3 CO 2 SO 3 SiO 2 NaCl 
 
 a. 4-4 2-3 4-2 6-6 4-3 0-9 3*0 2-4 71*9 = 100 
 
 b. 3-1 5-0 4-4 2-0 2-5 0-8 3-3 2*0 76*9 = 100 
 
 Traces of manganese were also found. The flowers and young shoots are said to yield 
 31-9 per cent, ash, and the stems 24*3 per cent. This, together with the very large 
 proportion of chloride of sodium in the ash, seems to show that the plants analysed 
 were saturated with salt water. Aster tripolium grown on the same soil, likewise 
 yielded a very large amount of ash, containing about 65 per cent. NaCl in the stem 
 and leaves, and 30 per cent, in the flowers. 
 
 Chenopodium olidum. This plant contains an alkaloid having the composition 
 C 3 H 9 N, either trimethylamine or propylamine, to which its foetid odour appears to be 
 due. (Dessaignes, Compt. rend, xxxiii. 358.) 
 
 Chenopodium Quinoa. According to Volcker (Chem. Gaz. 1851, p. 129) quinoa 
 seeds dried at 100 C. contain 46*10 per cent, starch, 6-10 sugar and extractive matter, 
 4-60 gum, 5*74 oil, 8*91 casein with a little soluble albumin, 13-95 insoluble albumin 
 and other albuminoidal compounds, 9*53 vegetable fibre, 5*05 ash. The ash (after 
 deduction of sand and charcoal) contained 36*76 per cent, potash, 1*31 chloride of 
 sodium, 2*45 lime, 13*61 magnesia, 1*78 ferric oxide, 38*99 phosphoric anhydride, 3'36 
 sulphuric anhydride, and 2*19 silica. 
 
 CHERT. A term often applied to hornstone and to any impure flinty rock, in- 
 cluding the jaspers. (See Ure's Dictionary of Arts, Manufactures and Mines, i. 655.) 
 
 CHESSYX.XTE or CHESSY COPPER. Syn. with AZURITE. (See CARBONATES 
 OF COPPER, p. 784.) 
 
 CHESTER-LITE. See FELSPAR, 
 
 CHESTNUT. Castanea vesca. The fruit of this plant has been examined by 
 Payen (J. Pharm. [3] xvi. 279) and by Albini (Wien.Akad. Ber. xiii. 502). Payeu 
 found in 100 pts. : 
 
 
 
 Ash 
 
 Nitrogen. 
 
 
 Water. 
 
 In dry 
 Substance. 
 
 In fresh 
 Substance. 
 
 In dry 
 Substance. 
 
 After 
 deducting 
 Ash. 
 
 Of the cultivated chestnut . . 
 
 54-21 
 
 4*04 
 
 0-53 
 
 1*17 
 
 1*21 
 
 Of the wild chestnut . . . 
 
 48-06 
 
 3*21 
 
 0-50 
 
 0-96 
 
 0-99 
 
 Albini found in the shelled kernels of dried chestnuts from various parts of Italy : 
 3*03-3 per cent, ash, 1*22*1 fat, 23*238-0 starch, 22-823*3 dextrin, 17*5 17*9 
 sugar, 6*58-4 cellulose, 0*9 2*1 vegetable albumin, and 5'2 5-3 so-called protein- 
 compounds. 
 
 According to Dessaignes (J. Pharm. [3] xxv. 28), chestnuts contain a little aspar- 
 agine, but no quercite. 
 
 The entire fruit of the tree (undried) yields 0*99 per cent, ash, containing in 100 pts. 
 39*36 KX), 19*18 Na 2 0, 7*84 Ca 6 0, 7*84 Mg 2 0, 5*48 Mn 4 3 [?], 3*88 SO 3 , 2-32 SiO 2 , 
 7*33 P 2 5 , 1*9 phosphates of calcium, magnesia, and iron, 4*82 NaCL (T. Kichard- 
 son, Jahresber. d. Chem. i. 1074.) 
 
 CHIASTOLITE. Hollow Spar. Made. Al 4 3 .Si0 2 . A variety of Andalusite 
 crystallised in right rhombic prisms with angles of 91 35' and 88 27'. On looking 
 into the end of the prism, we perceive in the axis of it a blackish prism, surrounded 
 by the other, which is of a greyish, yellowish, or reddish-white colour. From each angle 
 of the interior prism, a blackish line extends to the corresponding angle of the exterior. 
 In each of these outer angles there is usually a small rhomboidal space, filled with the 
 same dark substance which composes the central prism. The black matter is the same 
 clay-slate with the rock in which the chiastolite is imbedded. Fracture, foliated, with 
 double cleavage. Translucent. Scratches glass. Eubbed on sealing-wax it imparts 
 negative electricity. Specific gravity 2*94. Hardness 3 7*5. Before the blowpipe 
 it is convertible into a whitish enamel, It has been found in Britany, in the Pyrenees, 
 
CHICA CHINOLINE. 869 
 
 in che valley of Barege, and in Galicia in Spain, near St. lago de Compostella. The 
 interior black crystal is properly an elongated four-sided pyramid. U. 
 
 CHIC A. A red dye, obtained from the leaves of Bignonia Chica. (See CAEAJUBU 
 p. 747.) 
 
 CHIIiDRENITE. A phosphate of aluminium and iron (ferrosum) found with 
 apatite at Tavistock in Devonshire, and at Crinnis in Cornwall. Kammelsberg found 
 in two specimens : 
 
 P 2 S A1 4 Fe 2 Mn 2 Ca 2 Mg 2 H 2 Total. 
 
 I. . . 29-36 18-77 3075 6-12 0'66 17'00 102-06 
 
 II. . . 28-92 14-44 30-68 9'07 0-14 16'98 100-23 
 
 (after deducting 3'82 per cent of insoluble residue in I. and 4'03 in II.) 
 
 From the analysis II., which was made with purer material than I., Kammelsberg 
 deduces the formula : 2(4M 2 O.P 2 5 ) + 2A1 4 3 .P ;: S + 15H 0, which may be reduced to 
 that of an orthophosphate with hydrate of aluminium and water, viz. : (Ma)P 3 12 . 
 SflftlO + 5aq. The crystals belong to the trimetric system : P . fP . 3Poo . Poo . oop 
 and OP.' Cleavage parallel to P and oopoo (Brooke, Eammelsberg). Specific gravity 
 = 3-247. Hardness = 5 (Eammelsberg). The crystals, which are transparent, 
 have a glassy lustre, and vary in colour from yellowish-brown to blackish, are found 
 on the surface of spathic iron ore intergrown with quartz, iron pyrites, and copper 
 pyrites. (Brooke, Ann. Phil. vii. 316. Kammelsberg, Pogg. Ixxxv. 435 ; Phil, Mag. 
 [4] iv. 118.) 
 
 CHILEITE. Syn. with GOTHITE. 
 
 CHILTOrilTE. Syn. with PEEHNITE. 
 
 CRINOLINE. C 9 H 7 N. Qumoleine, Leucol (Runge, Pogg. Ann. xxxi. 68. 
 Gerhardt, Ann. Ch. Pharm. xlii. 310; xliv. 279. Hofmann, ibid. xlvi. 31; liii. 
 427; Ixxiv. 15. Bromeis, ibid. Hi. 130. Laurent, Ann. Ch. Phys. [3] xix. 367. 
 C. Greville Williams, Ed. Phil. Trans, xxi. [2] ; [3] 377; Jahresber. d. Chem. 
 1855, p. 548; 1856, p. 532. v. Babo, J. pr. Chem. Ixxii. 73, Gm. xiii. 243). 
 Kunge, in 1839, obtained from coal-tar an organic base to which he gave the name of 
 leucol. Gerhardt, in 1842, obtained a similar product, quinoleine, by distilling quinine 
 and other organic bases with potash. Hofmann showed that Gerhardt's quinoleine 
 and Kunge' s leucol were identical. Laurent first pointed out that Gerhardt's quino- 
 leine was a mixture, a fact afterwards established by Gr. Williams, who separated 
 pure chinoline from it, as well as from the mixture of bases obtained from coal-tar. 
 According to later experiments by Williams, however, the chinoline from coal-tar 
 appears to differ in some respects from that which is obtained from cinchonine, &c. 
 Williams has also succeeded in preparing from chinoline (obtained from cinchonine), 
 a fine blue colouring matter likely to be useful in dyeing. 
 
 Formation. Chinoline is produced in numerous reactions : 1. In the dry distilla- 
 tion of coal, passing over with the tar (Runge). 2. By distilling cinchonine, quinine, 
 or strychnine with hydrate of potassium (Gerhardt). 3. By the electrolysis of 
 nitrate of cinchonine (v. Babo). 4. By distilling thialdine with milk of lime 
 (Wohler and Liebig, Ann. Ch. Pharm. Ixi. v.) 5. By the dry distillation of tri- 
 genic acid or trigenate of silver (Liebig and Wohler, ibid. lix. 289). 6. By dis- 
 tilling berberine with milk of lime, or hydrate of lead (Bodeker, Ann. Ch. Pharm. 
 Ixix. 43). Bodeker also states that chromate of pelosine heated to 100 C. gives off a 
 mixture of chinoline and phenic acid; but according to Williams (Jahresber. d. 
 Chem. 1848. p. 375), the only volatile products of this decomposition are methylamine, 
 dimethylamine, and a pyrrol-base. Williams is of opinion that the production of 
 chinoline in some of the above reactions has been inferred merely from its odour, 
 when, in reality, not a trace of it has been present. 
 
 Preparation. 1. From Cinchonine. Pulverised cinchonine is gradually added to 
 hydrate of potassium, which is heated in a retort till it melts ; the mixture is then raised 
 to a higher temperature till it becomes brown and emits stifling vapours (Gerhardt); 
 and the distillate, which is a mixture of several bases, is boiled with an acid for 
 several days, whereby pyrrhol is driven off. The dry chinoline which afterwards 
 distils over, beginning to boil at 149 C., but not passing over in large quantities till 
 the boiling point rises to 183, is separated by repeated fractional distillation (about 
 200 times) into several portions, the lowest of which boils between 154 and 160, 
 and the highest, which is the largest in quantity, at 271. Of these fractions, that 
 which distils below 165 contains lutidine, with a little pyridine and picoline; that 
 between 177 and 182 contains collidine, which is also found in the products up to 
 199 & ; and the portion which distils above 199, especially that between 216 and 
 243, consists of chinoline and lepidine, the latter being found chiefly in the portion 
 
 3x3 
 
870 CRINOLINE. 
 
 boiling above 270. To obtain chinoline (and the other bases) perfectly pure, the 
 individual fractions are converted into platinum-salts, and separated by fractional 
 crystallisation. ("Williams.) 
 
 2. From Coal-tar Oil. a. The mixture of phenylamine and chinoline (leucol), 
 obtained from heavy coal-tar oil (see PHENYLAMINE), is dissolved in absolute alcohol, 
 and neutralised with oxalic acid ; and the mother-liquor decanted from the oxalate 
 of phenylamine which has crystallised out, is distilled with potash, the receiver being 
 changed as soon as the distillate no longer produces a blue colour with hypochlorite 
 of calcium, and the chinoline which afterwards passes over is collected apart ( H o f - 
 mann). Chinoline thus obtained, contains lepidine and other bases ("Williams). 
 b. Fifty gallons of the oil of very high boiling point, and heavier than water, are treated 
 with sulphuric acid, and the acid liquid is distilled with lime. The portion of the dis- 
 tillate which sinks in water, contains chinoline, lepidine, &c., together with a number 
 of bases of the phenylamine series. The latter are decomposed with nitrite of potas- 
 sium and hydrochloric acid (see PHENYLAMINE) ; the acid liquid is distilled from the 
 heavy oil containing phenic acid ; the admixed non-basic oils are expelled by passing 
 steam through the liquid ; the residue is filtered through charcoal ; and the bases are 
 separated from the aqueous solution by potash, and dried over sticks of solid potash. 
 The mixture thus obtained yields, after more than a hundred fractional distillations, 
 portions boiling between 177 and 274, and from these the chinoline is separated by 
 fractional crystallisation of the platinum-salts, as above. (Williams.) 
 
 Properties. Chinoline is a transparent, colourless, strongly refracting, mobile oil, 
 which neither thickens or freezes at 20 C. (Ho fmann, Br om eis). Specific gravity 
 1-081 at 10 (Hofmann). It conducts electricity less readily than phenylamine 
 (Hofmann), boils steadily at 238 C. and distils without alteration (Willi ams) : it 
 evaporates even at ordinary temperatures, so that the oil-stain which it produces on 
 paper soon disappears. The vapour-density of chinoline boiling between 238 and 
 243 C. is 4-519 (Williams). Chinoline has a penetrating odour, likfe that of phos- 
 phorus and of hydrocyanic acid (Eunge), of St. Ignatius' bean (Gerhardt), of 
 bitter-almond oil (Hofmann). It does not appear to be poisonous (Gerhardt). 
 The aqueous solution kills leeches, but when introduced into the stomach of a rabbit, 
 produces only transient convulsive symptoms and prostration of strength. It is 
 alkaline to litmus and turmeric (G-erhardt, Bromeis); only to dahlia-paper 
 (Hofmann). 
 
 Several formulae have been proposed for chinoline. According to the analyses of 
 Hofmann and Bromeis (made on chinoline containing lepidine, according to Williams), 
 it is C 9 H 8 N ; Gerhardt at first regarded it as C 8 H U NO, afterwards (Traite, iv. 449) as 
 C 10 H 9 N. The formula C 9 H 7 N, first suggested by Laurent, is confirmed by Williams's 
 analyses of several of the salts ; the pure base does not appear to have been analysed. 
 The formula C 9 H 7 N gives for the vapour-density, calculated to two volumes, the number 
 4 '47 which agrees very nearly with Williams's determination. 
 
 Chinoline is very sparingly soluble in cold water, rather more in hot water and is 
 extracted from the solution by ether (Hofmann). When shaken up with water at 
 C. it forms a clear oil containing 2C 9 H 7 N.3H 2 O, which at 15 C. gives up water and 
 becomes turbid. When chinoline saturated with water at 0C. is heated to 100, water 
 and a little chinoline escape, and a clear hydrate remains, containing 2C 9 H 17 N.H 2 0, 
 which remains limpid and mobile at 20, but is resolved by distillation into water and 
 anhydrous chinoline. (Bromeis.) 
 
 Chinoline mixes in all proportions with sulphide of carbon, alcohol, ether, wood- 
 spirit, aldehyde, and acetone ; it also mixes with oils, both fixed and volatile. It 
 dissolves phosphorus, sulphur, and arsenic, also common camphor and colophony, but 
 not copal or caoutchouc. It does not coagulate albumin. 
 
 Decompositions. 1. Chinoline when set on fire, burns with a luminous but smoky 
 flame. 2. It becomes resinised by exposure to the air. 3. Chlorine instantly changes it 
 into a black resin, with great rise of temperature and evolution of hydrochloric acid 
 (Hofmann), into a yellow oil, which is decomposed by water, leaving a white 
 insoluble substance (Williams). 4. With bromine, it forms a similar resin (Hof- 
 mann). 5. Aqueous chinoline treated with a mixture of hydrochloric acid and 
 chlorate of potassium rapidly becomes covered with a layer of orange-red oil, which 
 solidifies to a tough mass on cooling (Hofmann). 6. Fuming nitric acid acts 
 violently on chinoline, and converts it into a splendid mass of crystals, but does not 
 form any products of decomposition (Gr. Williams). 7. Chinoline immediately 
 takes fire in contact with dry chromic acid, and is resinised by aqueous chromic acid 
 (Hofmann). 8. Permanganate of potassium decomposes chinoline into oxalic acid 
 and ammonia Hofmann). Potassium dissolves in chinoline, with evolution of hy- 
 drogen, but without colouring. On melting potassium in chinoline vapour, cyanide of 
 potassium is formed. Chinoline vapour passed over burnt tartar, remains for the most 
 
CHINOL1NE. 871 
 
 part unchanged, but forms a small quantity of cyanide of potassium (Hofmann). 
 10. Chinoline passed over red-hot quick lime (Hofmann), or soda-lime (Bromeis), 
 suffers little or no decomposition. 11. Enclosed in a sealed tube with iodide of methyl, 
 and heated for ten minutes to 100 C-, it is changed into crystals of hydriodate of methyl- 
 chinoline. In like manner, it is converted by iodide of ethyl into hydriodate of ethyl- 
 chin oline, and by iodide ofamylinto hydriodate of amyl-chinoline (Williams). 
 12. Chinoline becomes warm when mixed with sulphide of methyl (sometimes disengag- 
 ing vapour of methylic ether and methylic alcohol), and forms, if complete combination 
 has been promoted by heat, a liquid soluble in water, which, when excess of sulphate 
 of methyl is present, deposits separate crystals. The liquid is rendered turbid by 
 potash or baryta, and separates oil-drops, which at first become red, then green, 
 finally violet, and when heated pass into a beautiful violet resin, methylirisine, with 
 formation of sharp, strongly smelling, condensable vapours. At the same time a brown 
 resin and a sulphomethylate are formed. Chinoline, heated to boiling with sulphate 
 of ethyl, forms a colourless liquid, which, when boiled with strong caustic potash, de- 
 posits a violet resin, cthylirisine, insoluble in ether, and a brown resin soluble in ether, 
 while an ethylsulphate remains dissolved, and a sharp neutral oil, sinking in water, 
 passes over, which, if immediately mixed with dichloride of platinum, yields beautiful 
 needles, but soon decomposes (v. Babo). 13. Chloride of acetyl acts violently on 
 chinoline, forming a crystalline very deliquescent mass (Williams). 14. With 
 cyanate of ethyl, it solidifies into a crystalline mass consisting of phenyl-chinyl-car- 
 bamide, N 2 (CO)".C 6 H 5 .C 9 H 5 .H 2 . 
 
 CHINOLINE SALTS. Chinoline unites with acids, forming salts which crystallise 
 easily (Williams). It precipitates salts of aluminium and ferricum, and renders 
 lead-salts and ferrous salts slightly turbid (Hofmann). Acoording to G-erhardt, it 
 precipitates nitrate of silver, but not ferric nitrate. 
 
 Chinoline salts are decomposed by fixed alkalis ; also by ammonia at a moderate 
 heat ; but at high temperatures, chinoline expels ammonia. Dry chinoline-salts treated 
 with phenylamine, emit the odour of chinoline. (Hofmann.) 
 
 Chlorhydrate or Hydrochlorate of Chinoline. Chinoline absorbs hydro- 
 chloric acid gas violently, and with evolution of heat, and solidifies on cooling to 
 white crystals, which take up more hydrochloric acid, becoming red and liquid, and on 
 again cooling, solidify to a deliquescent, slightlv crystalline mass. Hence chinoline 
 appears to form both a neutral and an acid hydrochlorate (Bromeis). When hydro- 
 chloric acid gas is passed over chinoline dissolved in ether, the hydrochlorate separates 
 in heavy viscous drops, which after a while become slightly crystalline (Hofmann). 
 Mixed with solutions of metallic chlorides, it forms double salts, which for the most 
 part crystallise readily. 
 
 Chlorantimonite. Chinoline forms with trichloride of antimony a white precipitate, 
 
 which dissolves in boiling hydrochloric acid, and crystallises on cooling (Hofmann). 
 
 Chloro-aurate. C 9 H 7 JST.HCl.AuCl 3 . Delicate canary -yellow needles, permanent in 
 
 the air, sparingly soluble in water, and containing, when dried at 100C. 41 '85 per 
 
 cent, of gold; the formula requires 4 2-0 per cent. (Williams.) 
 
 Chlorocadmate. C 9 H 7 N.HCl.PtCl 2 . The concentrated solutions of hydrochlorate of 
 chinoline and chloride of cadmium solidify to a pulp when mixed : the dilute solutions 
 yield white permanent needles, which give off 2 at. water at 100C., volatilise com- 
 pletely at a higher temperature, and are sparingly soluble in alcohol. (Williams.) 
 
 Chloromercurate. C 9 H 7 N.2HgCl. White precipitate, which is not decomposed by 
 boiling water (Hofmann), and separates on cooling in beautiful pearly plates 
 (Bromeis). It smells of chinoline, and has a very bitter, disagreeably metallic taste. 
 According to Hofmann's analysis, it contains 26-5 per cent. C, 17'6 Cl, and 49-9 Hg, 
 the formula requiring 27 '0 C, 1775 Cl, and 50'0 Hg. 
 
 Chloropalladite. C 9 H'N.HCl.PdCl. Chestnut-brown crystals, containing 20*96 per 
 cent. Pd; by calculation 21-18 per cent. (Williams.) 
 
 Chloroplatinate. C 9 H 7 N.HCl.PtCl 2 . Yellow crystalline precipitate, which dissolves 
 in 893 pts. of water at 15 C. (Williams). The salt obtained by fractional crystal- 
 lisation, fourteen times repeated, from a portion of the bases (prepared from cinchonine, 
 p. 869), boiling between 238 and 243, yielded 32*36 per cent. C, 274 H, and 29'29 
 Pt, the formula requiring 32-06 C, 2'58 H, and 29-19 Cl. (Williams.) 
 
 Chlorostannite. Hydrochlorate of chinoline forms with protochloride of tin, a yel- 
 low, heavy oil, which afterwards becomes crystalline, and dissolves with difficulty in 
 alcohol. (Hofmann.) 
 
 Chloro-uranate. C 9 H 7 KHC1.(U 2 0)CL Concentrated solutions of ammonio-chloride 
 of uranyl and hydrochlorate of chinoline, solidify when mixed : dilute solutions yield 
 beautiful yellow prisms, containing (at 100 C.) 31*87 per cent. C, 277 H, and 20-97 Cl, 
 the formula requiring 32'05 C, 2'37 H, and 21-07 Cl. (Williams.) 
 
 3x4 
 
872 CRINOLINE. 
 
 Chromate of Chinoline. Chromic acid forms a yellow crystalline precipitate 
 with chinoline (G-erhardt, Hofmann). Dilute chromic acid added in excess to 
 aqueous chinoline (obtained from cinchonine), throws down a small quantity of resinous 
 matter, which becomes crystalline when rubbed with a glass rod, dissolves in boiling 
 water after filtering and washing, and is deposited in brilliant needles on cooling. It 
 detonates when heated, but not after addition of hydrochloric acid. The crystals gave 
 by analysis, 45-08 per cent. C, 3'49 H, and 22-34 Cr, agreeing very nearly with the 
 formula 2C 9 H 7 N.H-'0.2Cr 2 3 (Williams). Chinoline from coal-tar did not yield a 
 crystallised compound with chromic acid, but only oily drops, even when the impurities 
 which could be destroyed by chromic acid had been removed. (Williams.) 
 
 Nitrate of Chinoline. Solution of chinoline in excess of nitric acid, leaves when 
 evaporated over the water-bath, a pasty mass, which solidifies on cooling, and when 
 crystallised from hot alcohol, forms white needles, permanent in the air, infusible at 
 100 C., and consisting of C 9 H 7 N.HN0 3 (Williams). Easily soluble in water and 
 alcohol, insoluble in ether. (Hofmann.) 
 
 Oxalate of Chinoline, is a confused, radiating, unctuous mass, easily soluble in 
 water, alcohol, and ether (H o f ma n n). An acid oxalate, C 9 H 7 N.C 2 H 2 4 , is obtained on 
 mixing a solution of 16-5 pts. oxalic acid in a small quantity of water with 243 pts. 
 of chinoline, as a soft, white, crystalline mass, which when recrystallised from alcohol, 
 forms slender needles having a silky lustre. It decomposes at 100 C., with evolution 
 of chinoline. (Williams.) 
 
 When chinoline containing phenylamine is dissolved in alcohol or ether, and mixed 
 with alcoholic oxalic acid, almost all the oxalate of phenylamine is deposited after a 
 few hours, while oxalate of chinoline remains in solution. (Hofmann.) 
 
 Picrate of Chinoline resembles picrate of phenylamine. (Hofmann.) 
 
 Sulphate of Chinoline. Crystallisable and deliquescent. (Gerhardt and 
 Hofmann.) 
 
 Tannate of Chinolin e. Chinoline forms with infusion of galls, a yellowish-brown 
 precipitate (Hofmann); a white flocculent precipitate, soluble in boiling water and 
 in alcohol (Gerhardt.) 
 
 Substitution-Derivatives of Chinoline. 
 
 METHYL-CHINOLINE, C 10 H 9 N=KH.CH 3 .C 9 H 5 . (Gr. Williams, Ed. Phil. Trans, 
 xxi. [3] 577.) Not known in the free state, at least in definite form. The hydriodate is 
 obtained in fine crystals, by heating chinoline and iodide of methyl together to 100 C. 
 in a sealed tube for ten minutes. It is decomposed by oxide of silver, forming iodide 
 of silver, and an unstable, strongly alkaline solution, which when heated with potash 
 emits a suffocating odour, probably arising from methylamine. The platinum-salt, 
 C 10 H 9 N.HCl.PtCl 2 , is obtained as a sparingly soluble salt, by decomposing the solution 
 of the hydriodate with nitrate of silver, precipitating the excess of silver with hydro- 
 chloric acid, and adding dichloride of platinum to the filtrate. 
 
 ETHYL-CHINOLINE, CHN = KH.C 2 H 5 .C 9 H 5 . (Gr. Williams, loc. tit.} 
 
 Chinoline treated with iodide of ethyl, as in the preparation of hydriodate of 
 methylchinoline, yields, after distilling off the excess of iodide of ethyl, crystals oi 
 hydriodate of ethylchinoline. On treating these crystals with oxide of silver and water 
 (if this is done in the water-bath, a volatile product escapes which attacks the eyes), 
 and filtering off the iodide of silver, a colourless, strongly alkaline solution of ethyl- 
 chinoline is obtained, which decomposes on evaporation in the water-bath, assuming a 
 carmine colour, and on the edges emerald-green, afterwards changing to a beautiful 
 blue. It expels ammonia from sal-ammoniac. It precipitates chloride of mercury and 
 the salts of lead, iron, and copper. 
 
 Hydriodate of Ethylchinoline, C U H U N.HI, forms cubes when recrystallised from al- 
 cohol. It is more soluble in water than in alcohol. It gives by analysis, 46-5 per cent. C, 
 4-4 H, and 44-1 I, the formula requiring 46-3 C, 4-9 H, and 44-6 I. 
 
 At 100 C., it becomes transiently blood-red. It is decomposed by sulphate of silver, 
 forming iodide of silver, and a liquid which is colourless at first, but on evaporation 
 over the water-bath, assumes a carmine colour, dark blue at the edges, and when dry 
 leaves a blackish-red mass having a coppery lustre. The mass forms with water a 
 dark carmine solution, which is coloured scarlet by hydrochloric and nitric acids, and 
 rose-red by ammonia : with potash, it forms a violet precipitate which is but sparingly 
 soluble in water, but dissolves in alcohol, forming a carmine-red solution. Dichloride 
 of platinum produces in the hydrochloric acid solution of the precipitate, a bulky, 
 insoluble double salt, of a higher atomic weight than the platinum -salt of hydrochlorate 
 of ethylchinoline. 
 
 Platinum-salt of Ethylchinoline. C' 'IP'N.HCLPtCl. Golden-yellow, sparingly so- 
 luble precipitate. 
 
CHIOLITE. 873 
 
 Respecting v. Babo's compounds, methyl- and ethyl-irisine, which appear to be iso- 
 meric with methyl- and ethyl-chinoline, see p. 870 ; also the names of the substances 
 themselves. 
 
 AMYL-CHINOLINE, C 14 H 17 N = N.H.C'H^.C 9 !!' (Gr. Williams, loc. tit.) A 
 mixture of chinoline and iodide of amyl heated in a sealed tube for several hours to 
 100 C., deposits beautiful crystals of the hydriodate, C 14 H 17 N.HL The platinum- 
 salt, C 14 H 17 N.HCl.PtCF, is sparingly soluble in water, insoluble in ether-alcohol. 
 
 Hydriodate of amyl-chinoline heated with alkalis, yields a fine blue colour, which 
 may be used as a dye. To prepare it, 1 pt. by weight of crude chinoline is to be boiled 
 for ten minntes with If pts. of iodide of amyl. The mixture, from being straw-coloured 
 becomes deep reddish-brown, and solidifies on cooling to a mass of crystals. This 
 product of the reaction is to be boiled for about ten minutes with 6 pts. of water, and, 
 when dissolved, filtered through paper. The filtered liquid is to be gently boiled in 
 an enamelled iron pan over a small fire, and exceess of ammonia gradually added. 
 The ebullition may be prolonged with advantage for one hour, the evaporation of the 
 liquid being compensated for by the gradual addition of weak solution of ammonia, 
 prepared by the admixture of equal volumes of ammonia of the density of 0*880 and 
 distilled water. The hour having elapsed, the whole is allowed to cool, when the 
 colour will almost entirely have precipitated, leaving the supernatant liquid nearly 
 colourless. On pouring the fluid away (preferably through a filter, in order to retain 
 floating particles of colour) the dish will be found to contain resinous looking masses 
 which dissolve readily in alcohol, yielding a rich purplish-blue solution, which may be 
 filtered and kept for use. 
 
 The colour prepared as above is of a purplish tint, but if a purer blue be required 
 the following modification is to be resorted to. The filtered aqueous solution of hy- 
 driodate of amyl-chinoline, is, as before, to be brought to the boiling temperature ; but 
 instead of adding ammonia, a solution of caustic potash containing about one-fifth of 
 its weight of solid potash is to be substituted. The addition is to be continued at 
 intervals until three-fourths as much potash has been added as is equivalent to the 
 iodine in the iodide of amyl used. The fluid may, after a quarter of an hour's ebul- 
 lition, be filtered to separate the resinous colour. The product is a gorgeous blue with 
 scarcely any shade of red. On adding the other fourth of potash to the filtrate whilo 
 gently boiling, a black mass will be precipitated containing all the red, which other- 
 wise would have been mixed with the blue. This mass dissolves readily in alcohol, 
 yielding a rich purple solution containing, however, an excess of red. The alcoholic 
 solution, on filtration, leaves on the filter a dark mass soluble in benzene, and as some- 
 times prepared, affording a brilliant emerald-green solution of great beauty. It is not 
 always easy to obtain this green colour. 
 
 It is only the chinoline prepared from cinchonine that yields these colouring matters : 
 a fact which points to an essential difference between this product and the isomeric 
 base found among the products of the distillation of coal. Cinchonine distilled with 
 excess of potash, yields about 65 per cent, of crude chinoline ; and all the distillate 
 which, on rectification (p. 869), distils above 199 or 209 C. (390 or 408 F.), up 
 to the highest range of the mercurial thermometer, is suitable for the preparation 
 of the colour. One pt. of this distillate and 1^ pts. iodide of amyl, yield 23 pts. of 
 blue dye containing 4 per cent, of solid colouring matter. (Grr. Williams, Chemical 
 News, 1861, p. 219.) 
 
 Chinoline-violet and chinoline-blue are resinous substances, which present a coppery 
 appearance by reflected light, but when in very thin layers, appear of a violet or blue 
 colour by transmitted light. 'They are bases and dissolve in acids, forming pale red 
 solutions, which ammonia restores to their original colours. They are slightly soluble 
 in hot water. Tannin precipitates them from their aqueous solutions, apparently 
 forming an insoluble compound. Reducing agents do not affect their shade of colour. 
 (W. H. Perkin, Chem. Soc. Qu. J. xiv. 246.) 
 
 Two volumes of chinoline-blue mixed with 1 vol. of Magenta pink (fuschine), of the 
 ordinary strength found in commerce, form a fine purple inclining to blue (Williams). 
 When chlorine is passed through an alcoholic solution of chinoline-blue, a green 
 liquid is produced, which is perhaps the green spoken of by Williams. (Perkin.) 
 
 CHIN ONE. Syn. with QUINONE. 
 
 CHIOIiXTZi. A fluoride of aluminium and sodium, Na 8 Al 4 F 9 , occurring at Miask 
 in the Ural, in snow-white, translucent, octahedral crystals, of the dimetric system, 
 in which the principal is to the secondary axes as 1 -07 7 : 1 ; also massive, granular 
 resembling cryolite, with crystalline structure. Specific gravity 272 (Hermann); 
 2-842 2-898 (Rammelsberg). Hardness = 4. Analysis by Hermann (J. pr. 
 Chem. xxxvii. 188), gave 2378 per cent. Na, 18-69 Al, the formula requiring 23-4 and 
 18-6. Fuses easily before the blowpipe, and gives the reaction of fluorine. (D a n a, ii. 98.) 
 
874 
 
 CHITIN. 
 
 CHITIN (from XITWV, a tunic). (Odier, Mem. Soc. d'Hist. Nat. de Paris, i. 29. 
 Lassaigne, J. China, med. ix. 379; Compt. rend. xri. 1087. Payen, Compt. rend, 
 xvii. 227. C. Schmidt, Zur vergleichenden Physiologic dcr wirbcllosen Thicrc. 
 1845, p. 32; and Ann. Ch. Pharm. liv. 298. Lehmann, Jahresber. d. ges. Med. 
 1844, p. 7. Fremy, Ann. Ch. Phys. [3] xliii. 94 ; Schlossberger, Ann. Ch. Pharm. 
 xcviii. 99. Stadeler, ibid. cxi. 21. Gerh. Traite, iv. 535. Pelouze et Fr6my, 
 TraitS, vi. 93.) The name given by Odier to the organic substance which forms the 
 elytrse and integuments of insects and the carapaces of Crustacea. It may be obtained 
 by exhausting the wing-cases of cockchafers successively with water, alcohol, ether, 
 acetic acid, and boiling alkalis. The final residue retains completely the form of the 
 wing-cases. Fremy prepares chitin by treating the tegumentary skeleton of a crus- 
 taceous animal with cold dilute hydrochloric acid, to remove calcareous salts ; washing 
 with distilled water ; boiling for several hours with solution of potash, which removes 
 adhering albuminous substances, and has no action upon chitin ; again washing with 
 distilled water ; and purifying the residue with alcohol and ether. 
 
 Chitin thus prepared is solid, transparent, of horny aspect, insoluble in water, alco- 
 hol, and ether. It is coloured brown by solution of iodine. Alkalis have no action 
 upon it. By boiling with dilute acids, it is resolved into glucose and a nitrogenous 
 compound. (Stadeler.) 
 
 When chitin (from the carapace of the crab) is boiled for several hours with dilute 
 sulphuric acid, only the softer membranes are attacked, while the more solid integu- 
 ments become loose and soft, and form, after pressing and washing with water, a mass 
 having almost the consistence of starch. The acid liquid supersaturated with lime, 
 and then neutralised with sulphuric acid, yields neither tyrosine nor leucine, but con- 
 tains ammonia, together with amorphous sugar, inasmuch as it precipitates cuprous 
 oxide abundantly from an alkaline solution of cupric oxide (Stadeler). Berthelot 
 (Ann. Ch. Phys. [3] Ivi. 149) likewise obtained sugar from chitin (prepared from the 
 integuments of lobsters, crabs, and cantharides, ) by macerating it in strong sulphuric 
 acid till it was dissolved, dropping the solution into one hundred times its volume of 
 boiling water, boiling for an hour, saturating with chalk, &c. 
 
 The above-mentioned pasty residue is coloured brown-red by iodine, like unaltered 
 chitin, and by prolonged boiling with sulphuric acid, yields an additional quantity of 
 sugar, while the undissolved portion always contains nitrogen. The same substance, 
 after removal of the acid, forms with water a turbid emulsion, which takes a long time 
 to clarify, and dries up by spontaneous evaporation to a soft skin-like membrane, which 
 exhibits, with iodine-water, the same reactions as the original chitin. (Stadeler.) 
 
 The composition of chitin is determined by the following analyses : 
 
 Carbon . 
 Hydrogen 
 Nitrogen 
 Oxygen 
 
 Schmidt. 
 
 Mean of 11 
 
 analyses. 
 
 46-64 
 
 6-60 
 
 6-56 
 
 40-20 
 
 Lehmann. Schlossberger. Stadeler. 
 
 46-73 
 6-59 
 6-49 
 
 40-19 
 100-00 100-00 
 
 46-64 
 6-60 
 6-56 
 
 40-20 
 
 100-00 
 
 46-32 
 6-65 
 6-14 
 
 40-89 
 100-00 
 
 Calculation 
 C9H15NQ6. 
 
 46-35 
 
 6-44 
 
 6-01 
 
 41-20 
 
 100-00 
 
 Fre'my found in chitin 43'35 carbon, 6-65 hydrogen and no nitrogen, whence he re- 
 gards chitin as isomeric with cellulose (44-4 C, 6-2 H, and 49-4 0). 'Gerhardt regarded 
 Fremy' s results^ as more correct than those of the German chemists, because chitin 
 yields by dry distillation only acetic acid and empyreumatic oil, without any ammonia, 
 and the products of its putrefaction under water are different from those of most nitro- 
 genous substances. But the analyses above given exhibit a closeness of agreement 
 which could scarcely be expected if the substances operated upon had been impure. 
 (See CELLULOSE, p. 818.) 
 
 Stadeler regards chitin as a glucoside, C 9 H 1S N0 8 , which is resolved by boiling with 
 acids into glucose and lactamide (or alanine or sarcosine) : 
 
 C 9 H I5 N0 6 + 2H 8 = C 6 H 12 6 
 
 If this decomposition really takes place, lactic acid should likewise be obtained as 
 a product of the transformation of the lactamide or alanine ; but the presence of 
 lactic acid among the products has not yet been demonstrated. Stadeler also suggests 
 that chitin (at least in Crustacea) may be formed by the union of lactate of ammonium 
 with gum, and elimination of water : 
 
 [C 3 H<0 3 .H.NH 
 
 Acid lactate of 
 ammonium 
 
 -r C 6 H'0 
 Gum. 
 
 C 9 H I5 N0 6 
 Chitin. 
 
 2H 2 0], 
 
 inasmuch as he has found gum in the juices of crabs and other Crustacea, and the pre- 
 
CHIVIATITE CHLORACETIC ACIDS. 875 
 
 sence of lactic acid in the gastric juice of the lower animals is by no means im- 
 probable. 
 
 CHIVIATITE. A sulphide of lead and bismuth, also containing copper, from 
 Chiviate in Peru, where it occurs, with pyrites and heavy spar, in foliated masses, 
 clearable in three directions in one zone, one making an angle with the second of 153, 
 and with the third of 133. Specific gravity 6*920; colour lead-grey; lustre metallic. 
 According to Kammelsberg's analysis (Pogg. Ann. Ixxxviii. 320) it contains 18'OOS, 
 60-95 Bi, 1673 Pb, 2'42 Co, 1'02 Fe, with trace of silver, and 0'59 insoluble matter 
 ( = 99-71), whence the formula 2(Pb ? ;Cu 2 )S.Bi 2 S 3 . (Dana, ii. 77.) 
 
 CHXiADXriTE. See METEORITES. 
 
 CHIiO AWTHITE. Native arsenide of nickel containing cobalt, also called white 
 nickel. (See NICKEL). 
 
 CHLOCARBETHAMIDE. Syn. with TBICKLOKACETAMIDE (p. 6). 
 
 CHXiORACETAIVKXC ACID. Syn. with TETBACHLOBACETAMIDE (p. 6). 
 
 CHXiORACETAIVXIDE. See ACET AMIDE (p. 6). 
 
 CHIiORACETXC ACIDS. Two of these compounds are known, viz. mono- and 
 tfr/-chloracetic acids, both being produced by the action of chlorine gas on glacial acetic 
 acid under the influence of light, the former when the acid is in excess, the latter 
 when the chlorine and the acetic acid are brought together in the exact proportions 
 required for its formation. The trichlorinated acid is likewise produced in several 
 other reactions. Zto'chloracetic acid has not yet been obtained, at least in definite form. 
 
 Blonochloracetic Acid, or simply Chloracetic Acid. C 2 H 3 C10 = C 2 H 2 C1O. 
 H.O. (R. Hoffmann, Ann. Ch. Pharm. cii. 1.) Dumas had observed that, in the 
 preparation of trichloracetic acid by the action of chlorine on acetic acid in sunshine, 
 a lower substitution-product is always obtained, especially if the acetic acid is in ex- 
 cess, in the form of an uncrystallisable acid, which however he did not succeed in pre- 
 paring in the separate state. F. Leblanc afterwards obtained this acid, the monochlor- 
 actic acid, in the form of a colourless liquid, by passing chlorine through glacial acetic 
 acid in the shade ; his product however was not quite pure. More recently Hoffmann 
 has shown that the chief product of the action of chlorine on excess of acetic acid in 
 sunshine, is monochloracetic acid, and that this acid, when pure, is solid and crystal- 
 line at ordinary temperatures. 
 
 Preparation. 1. A tubulated retort of about 1 litre capacity and containing from 
 half a pound to a pound of glacial acetic acid, is placed in a bath containing a saturated 
 solution of nitrate of sodium (boiling at 120 C.), and dry chlorine gas is passed into 
 the retort by a tube inserted through the tubulure and terminating just above the 
 liquid, so that the gas may mix immediately with the vapour of the acid. The neck 
 of the retort having a wide glass tube attached to it, is directed upwards, so that any 
 acetic acid which evaporates undecomposed may be condensed and flow back again, 
 while the hydrochloric acid and excess of chlorine escape. The whole apparatus is 
 placed in the sunshine, and the evolution of chlorine is so regulated that the upper part 
 of the retort always appears coloured by it. The stronger the light, the more rapid is 
 the absorption of chlorine ; but the action takes place, though slowly, even under a 
 clouded sky. A very slow substitution of chlorine for hydrogen likewise takes place in 
 the dark and at ordinary temperatures. As the formation of chloracetic acid goes on, 
 the action slackens, so that it is best, after about fifteen hours' exposure to sunshine, or 
 twice as long to diffused daylight, to expel the excess of chlorine from the apparatus by 
 a steam of dry air, and rectify the product in a smaller retort. The portion which dis- 
 tils below 130 C. consists almost wholly of unaltered acetic acid, and may be used in 
 a subsequent preparation. That which passes over between 130 and 190 is easily se- 
 parated, by repeated rectification, into acetic and a thick liquid which boils between 
 185 and 187, and either solidfies immediately into a mass of white needle-shaped 
 crystals, or yields after some time, large, isolated, transparent, colourless rhombic 
 tables, while the greater portion remains liquid, but if shaken up or stirred with a 
 glass rod, solidifies suddenly and with considerable rise of temperature, the crystals 
 previously formed becoming opaque and white like porcelain. The crystalline mass, 
 which melts between 45 and 47, consists of nearly pure monochloracetic acid, mixed 
 however with a certain quantity of liquid, which may be removed by decantation and 
 rapid pressure, and used, together with the portion of the original liquid which distilled 
 below 130, in a subsequent preparation. The expressed crystals are placed on bibu- 
 lous paper and completely dried in vacuo over oil of vitriol and a few lumps of hydrate 
 of potassium, and then redistilled, the first and last portions of the distillate being re- 
 jected. As they are very deliquescent, they should be kept as much as possible from 
 the air. (Hoffmann.) 
 
 In the first distillation and in the subsequent rectifications, there is obtained a small 
 quantity of a liquid which boils above 190 r and appears to contain an acetic acid with 
 
876 CHLORACETIC ACIDS. 
 
 more than 1 at. hydrogen replaced by chlorine. It yielded in different experiments 
 from 48 to 50 per cent, of chlorine, which does not agree with the formula either of 
 dichloracetic (requiring 55-04) or of trichloracetic acid (requiring 65'13 per cent, of 
 chlorine). In one experiment, this liquid, on being saturated with baryta, yielded, 
 besides monochloracetate of barium, a small quantity of small, opaque, warty crystals, 
 the composition of which seemed to show that they contained a higher chlorinated 
 acid ; but in no instance, even when the purest crystallised acetic acid was used and 
 the absorption took place in the brightest sunshine, was any definite dichloracetic or 
 trichloracetic obtained, the chief product being invariably monochloracetic acid. 
 Neither was any oxalic acid formed, as in Dumas' preparation of trichloracetic acid 
 (p. 877). (Hoffmann.) 
 
 2. Monochloracetic acid is also obtained in a state of purity by the action of water 
 on monochlorinated chloride of acetyL On distilling the liquid, the thermometer rises 
 from 100 to 180, and the liquid which passes over at that temperature solidifies in 
 a crystalline mass on cooling. (Wurtz.) 
 
 Properties. The acid crystallises from fusion in rhombic tables, having acute angles 
 of 77 or 78 ; from solution in acetic acid e.g. from the liquids obtained in the 
 first distillation between 180 and 186, and between 186 and 190 in crystals hav- 
 ing a prismatic character, and very much resembling those of trichloracetic acid. Melt- 
 ing point 62. It contracts strongly in solidifying, and generally gives off numerous 
 air-bubbles. The specific gravity of the melted acid at 73, is 1-366 as compared with 
 water at 19, and 1-3947 compared with water at 73. Boiling point from 185 to 
 187'8. It distils undecomposed, and when pure solidifies in the neck of the retort; 
 but if mixed with acetic acid, remains liquid below its ordinary point of solidification. 
 When kept for some time at a temperature near its melting point, it sublimes in long 
 spicular crystals. It is nearly inodorous at ordinary temperatures, but its vapour has 
 a pungent suffocating odour. It has a strong acid taste, attacks the cuticle, and raises 
 blisters if kept on it for some time. It deliquesces in the air, and dissolves very easily 
 in water, producing considerable fall of temperature. 
 
 Decompositions. 1. The acid is decomposed by pentacJiloride of phosphorus, with 
 formation of oxy chloride of phosphorus and monochlorinated chloride of acetyl, but the 
 two chlorides cannot be separated by distillation, as they both boil at about 110. 
 When the product was repeatedly distilled with small portions of acid chloracetate of 
 potassium, the residues of the last distillations yielded at high temperatures a large 
 proportion of chloracetic acid, the last portions of which boiled as high as 200, and 
 had a more penetrating odour, probably arising from the presence of a small quantity 
 of the anhydrous acid. 2. The acid heated with potash-ley, ammonia, baryta-wattr, 
 or lime-water, immediately yields a chloride of the alkali-metal and glycollic acid. 
 (Kekule.) 
 
 C 2 H 2 C1M0 2 + H 2 = MCI + C 2 H 4 3 . 
 
 3. Chloracetic acid is reduced by potassium-amalgam or sodium-amalgam to acetic 
 acid, in the same manner as trichloracetic acid ; the decomposition is however incom- 
 plete, and is attended with evolution of hydrogen. (Hoffmann.) 
 
 The CHLO&ACETATES, C 2 H 2 C1M0 2 , are obtained by digesting the oxides or carbo- 
 nates in the aqueous acid : they are for the most part easily soluble and crystallisable. 
 
 Chloracetate of Ammonium decomposes by evaporation like the potassium-salt. 
 It is more soluble than that salt, and solidifies only from a perfectly viscid solution, in 
 the form of a crystalline cake, which deliquesces on exposure to the air. 
 
 Chloracetate of Barium. C 2 H 2 ClBa0 2 + H 2 0. May be obtained, even with 
 very small quantities of material, in distinct prismatic crystals, apparently belonging 
 to the trimetric system, and containing 39'99 per cent, barium (by calculation 40-06). 
 Decomposes but little during evaporation, and separates out almost completely on cool- 
 ing from a hot saturated solution. (Hoffmann.) 
 
 Chloracetate of Potassium, a. Neutral. 2C 2 H 2 C1K0 2 + 3H 2 0. Obtained 
 by saturating the acid with carbonate of potassium and evaporating to a syrup in vacuo 
 over oil of vitriol. It then separates in thin colourless laminae, which may be obtained 
 pure by draining on bibulous paper. It is not deliquescent, and does not give up its 
 water of crystallisation at 100 C., but is decomposed at a higher temperature, yielding 
 chloride of potassium, glycollic acid, and a small quantity of glycolide, C 2 H 2 2 . 
 (Kekule, Ann. Ch. Pharm. cv. 288): 
 
 C 2 H 2 C1K0 2 = KC1 + C 2 H 2 8 . 
 
 It is also decomposed when its solution is evaporated at a gentle heat. It is very so- 
 luble in water. After drying in vacuo. it yielded 24-63 per cent, potassium (by calcu- 
 lution, 24-55). 
 
 b. Add, C 2 H 2 C1K0 2 .C 2 IFC10 2 . When a solution of the neutral salt is mixed with 
 
CHLORACETIC ACIDS. 877 
 
 as much acid as it already contains, the whole solidifies to a thick pulp of small white 
 pearly crystals, which may be purified by draining on bibulous paper or by drying over 
 oil of vitriol. Sparingly soluble in water. 
 
 Chlor acetate of Silver. C 2 H 2 ClAg0 2 . Ahot solution of the acid saturated with 
 oxide of silver, yields the salt on cooling in splendid rhomboi'dal, iridescent laminae 
 (Wurtz). Anhydrous. Dissolves sparingly in cold, more readily in hot water, and is 
 easily obtained by cooling, in small nacreous scales, which blacken on exposure to 
 light, and yield chloride of silver. Between 110 and 120 C. it decomposes with a kind 
 of explosion, emitting the same odour as the acid when it evaporates, and leaving 
 chloride of silver, mixed with a very small quantity of metallic silver. 
 
 Chloracetate of Ethyl. C 4 H 7 C10 2 = C 2 H 2 C10 2 .C 2 H 5 . (E. Willm, Ann. Ch. 
 Phys. [3] xlix. 97.) Obtained by the action of alcohol on monochlorinated chloride of 
 acetyl : 
 
 C 2 H 6 + C 2 H 2 C1 2 = C 2 H'C10 2 + HC1. 
 
 The action, which is very violent, must be moderated by cooling the vessel externally, 
 and as soon as it is finished, the product may be washed with water, dehydrated by 
 chloride of calcium and rectified. 
 
 Colourless liquid, having an ethereal odour and burning taste, heavier than water 
 and insoluble in that liquid. Boils at 143'5 C. when the barometer stands at 758 mm. 
 Vapour-density 4-46. 
 
 The ether burns with a bright flame, green at the edges. It is decomposed by 
 potash, into alcohol and chloracetic acid, which then suffers further decomposition, 
 yielding chloride and acetate of potassium. 
 
 Trichloracetic Acid. C 2 HC1 3 2 = C 2 C1 3 O.H.O. (Dumas, J. Chim. med. vi. 
 659; also Ann. Ch. Pharm. xxxii. 101; Ann. Ch. Phys. Ixxiii. 75; M els ens, Ann. 
 Ch. Phys. [3] x. 233 ; Malaguti, Ann. Ch. Phys. [3] xvi. 10 ; Kolbe, Ann. Ch. Pharm. 
 liv. 182 ; G-m. ix. 209; Grerh. i. 749.) This acid was discovered by Dumas in 1839. 
 It is produced : 1. By the action of 6 at. dry chlorine gas on 1 at. glacial acetic acid in 
 Bunshine (Dumas) : 
 
 C 2 H 4 2 + 6C1 = C 2 HC1 3 2 + 3HC1. 
 
 2. In the oxidation of soluble chloral by a mixture of hydrochloric acid and chlorate 
 of potassium, and of chloral either soluble or insoluble, by fuming nitric acid (Kolbe) : 
 
 C 2 HCPO + = C 2 HC1 S 2 . 
 
 3. By the action of chlorine gas in sunshine on dichloride of carbon covered with a 
 layer of water (Kolbe) : 
 
 C 2 C1 4 + 2H 2 + Cl 2 = C 2 HCP0 2 + 3HC1; 
 
 part of the C 2 C1 4 is at the same time converted into C 2 Cl a . 4. In the decomposition 
 of chloride of trichloracetyl (chloraldehyde) by water (Malaguti) : 
 
 C 2 C1 4 + H 2 = C 2 HC1 2 2 + HC1. 
 
 6. In the decomposition of perchlorinated formic ether by water (Cloez, Ann. Ch 
 Phys. [3] xvii. 300) : 
 
 C 3 C1 6 2 + 2H 2 = C 2 HC1 3 2 -f CO 2 + 3HC1. 
 
 Preparation. 1. When glacial acetic acid is exposed to the sun in bottles of 5 or 6 
 litres capacity (in the proportion of 0'8 or 0-9 grms. of the acid to 1 litre of chlorine) 
 crystals of trichloracetic acid make their appearance in about a day, together with a 
 small quantity of oxalic acid. On opening the bottles, a mixture of hydrochloric acid 
 gas with a small quantity of carbonic acid and a suffocating vapour, escapes with force. 
 The bottles are then left open for some hours, till the gaseous mixture is completely ex- 
 pelled, and washed out with a small quantity of water, whereby a concentrated solution 
 of trichloracetic acid is obtained, mixed, however, with hydrochloric acid, undecom- 
 posed acetic acid, and oxalic acid. When this solution is evaporated in vacuo over oil 
 of vitriol and hydrate of potassium, water, hydrochloric acid, and part of the acetic 
 acid escape, and the solution then yields crystals, first of oxalic, afterwards of trichlor- 
 acetic acid. The mother-liquor distilled with phosphoric anhydride, which decomposes 
 the oxalic acid, yields a distillate of acetic acid, and then, on changing the receiver, of 
 trichloracetic acid, which soon solidifies to a crystalline mass. Lastly, the crystals 
 are left for some hours in vacuo on several sheets of white blotting paper, so that the 
 admixed acetic acid may soak into the paper. (Dumas.) 
 
 2. Insoluble chloral is treated with faming nitric acid, and the action, which is at 
 first attended with evolution of heat and abundant evolution of red fumes, is afterwards 
 assisted by the application of a gentle heat, till the flakes of insoluble chloral have com- 
 pletely disappeared ; the greater part of the excess of nitric acid is then distilled off; 
 
878 CHLORACETIC ACIDS. 
 
 and the remaining portion is left to evaporate in vacuo over oil of vitriol and hydrate 
 of potassium. Crystallised trichloracetic acid then remains, free from nitric, acetic, 
 and oxalic acid, but generally retaining traces of chloral. (Kolbe.) 
 
 3. When dichloride of carbon, C 2 C1 4 , is placed in a bottle filled with chlorine gas, 
 covered with a film of water, and exposed to the sun, there is formed, besides O'Cl 6 , 
 an aqueous solution of trichloracetic acid, which may be obtained in the crystalline 
 state by evaporation in vacuo over oil of vitriol and lime. (Kolbe.) 
 
 4. Chloraldehyde is dissolved in water ; and the solution containing hydrochloric acid 
 is evaporated in vacuo over oil of vitriol and hydrate of potassium, whereby trichlor- 
 acetic acid is obtained in beautiful crystals. (Malaguti.) 
 
 Properties. Trichloracetic acid forms colourless rhombohedrons. It melts above 
 46 C., and in cooling begins to solidify at 45 ; if the mass be then shaken, the tem- 
 perature rises to 46, which is therefore the melting point. In the fused state, it has 
 a density of 1'617 at 46, that of water at 15 being I'OOO. Boils between 195 and 
 200 without any decomposition, and sublimes in the form of a silvery crust. Vapour- 
 density = 5'3, by calculation 5'637, the difference arising from partial decomposition. 
 The acid has a faint odour at ordinary temperatures, but when heated till it volatilises, 
 it emits a pungent and suffocating odour. It has a caustic, sour taste, and makes the 
 tongue white, like peroxide of hydrogen. It destroys the cuticle, causing it to peel off 
 on the following day, and if left for some time on the skin, produces blisters. It 
 reddens litmus strongly, but does not bleach it, even after a considerable time. It 
 deliquesces in the air and dissolves readily in water. (Dumas.) 
 
 Decompositions. 1. When the acid is heated with strong sulphuric acid, part of it 
 distils over unchanged, and crystallises in rhombohedrons ; the rest is resolved into 
 hydrochloric acid, carbonic anhydride, and carbonic oxide (Dumas). [Perhaps in this 
 manner: C 2 HC1 3 2 + H 2 = 3HC1 + CO + CO 2 ]. -2. When it is heated with 
 excess of potash-solution, ebullition takes place, continuing after the vessel has been 
 removed from the fire ; the first products of the action are chloroform and carbonate 
 of potassium ; but on further boiling with the alkaline liquid, the chloroform is resolved 
 into formate and chloride of potassium. (Dumas.) First : 
 
 C 2 HC1 S 2 + K 2 = CHC1 3 + K 2 C0 3 
 then: CHC1 3 + 2K 2 O = CHKO 2 + 3KC1. 
 
 When the acid is boiled with baryta-water, carbonate of barium is precipitated and 
 chloroform evolved (Dumas). 3. The acid boiled with excess of ammonia, is re- 
 solved into carbonate of ammonium, which sublimes, and chloroform, which sinks down 
 as an oil (Dumas) : 
 
 C 2 HC1 3 2 + (NH 4 ) 2 = (NH 4 ) 2 .C0 8 + CHC1 8 . 
 
 4. Aqueous trichloracetic acid, or either of its salts dissolved in water, is decomposed 
 by potassium-amalgam (1 pt. potassium to 150 pts. mercury) with evolution of heat, 
 and reconverted into acetate of potassium (Melsens). If the amalgam is not in 
 excess in proportion to the acid, no hydrogen is evolved. Antimonide of potassium, 
 or potassium alone, or zinc with sulphuric acid, does not effect the transformation, 
 but causes an evolution of hydrogen gas (Melsens). If instead of 6 at. potassium, 
 only 3 at. be used in the form of potassium- amalgam, no acetic acid is produced, but 
 apparently an acid containing a smaller quantity of chlorine than trichloracetic acid. 
 6. Zinc dissolves in aqueous trichloracetic acid, and forms, besides chloride of zinc, 
 a zinc-salt which appears to contain dichloracetic acid C 2 C1 2 H 2 2 . Trichloracetic 
 acid is also reduced to acetic acid in the galvanic circuit of a two-pair Bunsen's zinc- 
 carbon battery, with electrodes of amalgamated zinc. (Kolbe.) 
 
 T HI CHLOR ACETATES. Trichloracetic acid is monobasic, like acetic acid, the 
 formula of its salts being C 2 MCF0 2 . 
 
 Trichloracetate of Ammonium. C 2 (NH 4 )C1 3 2 + 2H 2 0. The aqueous acid 
 saturated with ammonia, and evaporated at ordinary temperatures, either in vacuo 
 or in the air, yields crystals (Dumas). The salt is likewise produced when trichlor- 
 acetamide is brought in contact with aqueous ammonia or very dilute nitric acid 
 (Malaguti, Cloez). It crystallises in beautiful prisms (containing 2 at. water, melts 
 at 80 ; boils between 110 and 115 C., giving off vapours of chloroform and acid car- 
 bonate of ammonium, the latter appearing in peculiar abundance at 145 ; and solidifies 
 at 160 in yellowish, micaceous scales of anhydrous trichloracetate of ammonium, 
 which are tasteless, dissolve readily in water, and give off ammonia when treated with 
 potash, even in the cold. At a higher temperature, these scales fuse, and are resolved 
 into carbonic oxide, phosgene, and sal-ammoniac vapour. (Malaguti.) 
 
 Decomposition of the crystallised salt : 
 
 C 2 (NH 4 )C10 2 + 2H 2 = CHOI 3 + NH'.F CO" + H 2 0. 
 
CHLORACETONES CHLORACETYPHIDE. 879 
 
 Decomposition of the anhydrous salt : 
 
 C 2 (NH 4 )C1 3 2 = CO + CCPO + NH 4 C1. 
 
 Trichloracetate of Potassium. 2C 2 KCP0 2 + H 2 0. The aqueous acid neu- 
 tralised with carbonate of potassium yields by spontaneous evaporation, silky needles, 
 which decompose with a kind of detonation when gently heated, and absorb only a 
 small quantity of water when exposed to damp air. (Dumas.) 
 
 The Barium and Calcium salts are neutral and dissolve very readily in water. 
 (Dumas.) 
 
 Trichloracetate of Silver. C 2 AgCl 3 2 . Recently precipitated oxide of silver 
 immersed in the aqueous acid is converted into grey laminse which dissolve in a larger 
 quantity of water, and crystallise therefrom by evaporation in vacuo over oil of vitriol 
 and in the dark, in crystalline granules and laminse. The salt is very readily decom- 
 posed by light. When heated on a sheet of paper, it detonates violently, giving off. 
 the same odour as trichloracetie acid when it evaporates, and leaves vegetations of 1 
 pure chloride of silver. If it be moistened with alcohol and the alcohol set on fire, it 
 decomposes more quietly, and without projection. (Dumas.) 
 
 Trichloracetate of Ethyl. Trichloracetic Ether. C 2 C1 3 2 .C 2 H 5 . Obtained 
 either by distilling trichloracetic acid with alcohol and a small quantity of sulphuric 
 acid (Dumas), or by gradually adding chloraldehyde to alcohol. (Malaguti.) 
 C 2 C1 4 + C 2 H 6 = C 2 C1 3 2 .C 2 H 5 + HCL 
 
 Chloral- 
 dehyde. 
 
 The product obtained by either of these processes is precipitated by water, washed 
 with water, and dried over chloride of calcium. It is a colourless oil, smelling Eke 
 peppermint. Specific gravity 1-367. Boiling point 164. Vapour-density 6'64. 
 
 Aqueous potash decomposes it, forming alcohol and trichloracetate of potassium : 
 C 2 C1 3 2 .C 2 H 5 + KHO = C 2 H 6 + C 2 C1 3 K0 2 . 
 
 Ammonia converts into trichloracetamide, N.H 8 .C 2 C1 3 (p. 22). 
 
 Exposed to the action of chlorine in daylight, and in direct sunshine, it yields the 
 same products as acetate of ethyl (p. 22). It is isomeric with the compound obtained 
 by passing dry chlorine through dichloracetie ether contained in a vessel, the upper 
 part of which is protected from the light. The two compounds are distinguished 
 from each other by their behaviour with potash, the latter yielding, not trichloracetate 
 of potassium, but chloride of potassium, deliquescent chlorinated potassium-salts, and 
 a sweet oily liquid no longer decomposible by potash. (Leblanc.) ' 
 
 The higher chlorinated compounds produced by the action of chlorine on acetate of 
 ethyl may be regarded as compounds of trichloracetic acid with ethyl in which the hy- 
 drogen is more or less replaced by chlorine : thus tetrachloracetic ether 4 H 4 C1 4 O 2 
 = C 2 C1 3 2 .C 2 H 4 C1; perchloracetic ether, C 2 C1 8 2 = C 2 C1 3 0.C 2 C1 5 . All these com- 
 pounds, indeed, when treated with potash, yield trichloracetate of potassium, e.g. : 
 
 C'C1 8 2 + 2KHO = 2C 2 C1 8 K0 2 + 2HC1. 
 Some of them however appear to be susceptible of isomeric modifications. 
 
 Trichloracetate of Methyl. C 2 C1 3 2 .CH 3 . Obtained by processes exactly 
 similar to those which yield the ethyl-compound, viz. by distilling the acid with wood- 
 spirit and sulphuric acid, or by the action of wood-spirit on chloraldehyde. It is a 
 colourless oil, heavier than water, and smelling like peppermint. It is isomeric with 
 the compound C 3 H 3 C1 3 O 2 , obtained by the action of chlorine on acetate of methyl. The 
 two compounds are not however identical ; for the former is converted by potash into 
 methyl-alcohol and trichloracetate of potassium (together with formate and chloride 
 of potassium resulting from the further action of the potash, p. 45) ; the latter when 
 treated with potash yields chloride and formate of potassium, together with chlorome- 
 thylase, CHC1. (Laurent, see p. 23.) 
 
 Trichloracetate of methyl exposed to the action of chlorine in sunshine, is converted 
 into perchloromethylic acetate, C 3 C1 C 2 , a compound also produced by the continued 
 action of chlorine on acetate of methyl. 
 
 CHLORACETONES. See ACETONE (p. 29). 
 
 CHLORACETONITRILE. See ACETONITRILE (p. 33). 
 
 CHIiORACETYXi. C 2 H 2 C1O. The radicle of chloracetic acid, chloracetamide, &c. 
 
 Triehloracetyl, C 2 CPO, is the radicle of trichloracetic acid, trichloracetamide, chloral, 
 chloraldehyde, chloralide, &c. 
 
 CKLORACETYPHIDE. Trichloraccphosphide. Pfiosphide of Trichloracett/l and 
 Hydrogen. C 2 H 2 CPPO = P.H 2 .C 2 C1 3 0. This compound, the analogue of trichlor- 
 acetamide, is produced by the action of chloride of trichloracetyl on phosphoretted 
 hydrogen : 
 
 C 2 C1 3 O.C1 + PH 3 = HC1 + P.H 2 .C 2 C1 8 0, 
 
880 CHLORAL. 
 
 also, together with oxychloride of carbon, when phosphoretted hydrogen is passed into 
 heated perchloroformic ether : 
 
 C 3 C1 6 2 + PH 3 = P.H 2 .C 2 C1 3 + COC1 2 + HC1. 
 
 It forms small, white, crystalline scales, having a slightly alliaceous odour and bitter 
 taste. It is permanent in the air at ordinary temperatures, but decomposes when 
 heated, leaving a carbonaceous residue containing phosphoric acid. It is insoluble in 
 water; slightly soluble in alcohol, ether, and wood-spirit. (Cloez, Ann. Ch. Phys. [3] 
 xvii. 309.) 
 
 _ CHLORAL. ^ Hydride of Trichloracetyl. C 2 HCPO = C 2 Cl 3 O.H._This body was 
 discovered by Liebig in 1832 (Ann. Ch. Pharm. i. 189), and further examined by 
 Dumas (Ann. Ch. Phys. [2] Ivi. 123) and Stadeler (Ann. Ch. Pharm. Ixi. 101). It 
 is the ultimate product of the action of chlorine upon alcohol : 
 
 C 2 H 8 + Cl 8 = C 2 HCFO + 5HC1. 
 
 Probably the alcohol is first converted into aldehyde by abstraction of 2H ; and in 
 this compound 3H are afterwards replaced by 3C1 (see ALCOHOL). Choral cannot, 
 however, be obtained by the direct action of chlorine on aldehyde ; it appears to be 
 produced in the first instance, but is quickly converted into other products. For the 
 production of chloral from alcohol, it is absolutely necessary that the alcohol be anhy- 
 drous ; if water is present, aldehyde, acetal, acetic acid, acetic ether, and other pro- 
 ducts are formed instead of chloral ; these products also accompany the chloral, even 
 when the preparation is made with absolute alcohol (see ALCOHOL, Decomposition by 
 CMorine, p. 74). Chloral is also produced by the action of chlorine on starch or 
 sugar. (Stadeler.) 
 
 Preparation. 1. From alcohol. Pure and dry chlorine gas is passed into absolute 
 .icohol contained in a tubulated retort having its neck directed upwards, and fitted 
 
 with a long condensing tube, which passes down 
 
 Fig. 127. j J to the bulb, and projects considerably above the 
 
 extremity of the neck to carry off uncondensed 
 gases ; the chlorine is introduced through the 
 tubulus. Or the alcohol may be contained in a 
 tube bent, as shown in fig. 127, the middle por- 
 tion being 2 or 3 ft. long, and placed at a slight 
 inclination, so that the chlorine entering at the 
 lower part, may pass through a column of alcohol 
 of considerable length but no great height. The 
 chlorine is best evolved from a mixture of common salt, peroxide of manganese and 
 sulphuric acid (which gives it off more regularly than hydrochloric acid and maganese); 
 it must be passed first through a wash-bottle containing water, and then through sul- 
 phuric acid or over chloride of calcium, to dry it. The unabsorbed chlorine, together 
 with hydrochloric acid gas and vapour of hydrochloric ether, may be passed into two 
 Woulfe's bottles, and thence into the open air, so that the operator may not be annoyed 
 by it. At the commencement of the operation, the alcohol is cooled by affusion of cold 
 water, to prevent it from taking fire and depositing soot ; but afterwards, when the 
 absorption of the chlorine diminishes, and the liquid assumes a yellow colour, it must 
 be gradually heated, and at last nearly to the boiling point ; 200 grammes of alcohol 
 require the passage of a rapid stream of chlorine to be continued for 15 or 20 hours, 
 involving a consumption of about 1200 litres of chlorine gas. The alcohol becomes 
 continually thicker, acquires a higher boiling point, and is finally converted into a 
 heavy syrup, which, after standing for some days, solidifies completely to a soft, white 
 crystalline mass, consisting of hydrate of chloral, together with a small quantity of 
 hydrochloric acid and undecomposed alcohol : Crude Hydrate of Choral. If a sample 
 of the liquid, after being agitated with four times its volume of sulphuric acid, and 
 set aside, does not in a few hours form a solid stratum of insoluble chloral above the 
 oil of vitriol, the passage of the chlorine must be continued for a still longer time. 
 The solidified crystalline mass is heated till it melts, briskly agitated with 4 to 6 
 times its bulk of sulphuric acid, which does not heat or blacken it ; left at rest till 
 the dehydrated chloral has risen to the top of the sulphuric acid, a result which may 
 be accelerated by gentle heating ; and the transparent, colourless film of chloral is 
 immediately decanted by means of a pipette. If the sulphuric acid contains water, 
 it is particularly necessary to decant as quickly as possible, before the chloral is 
 thereby converted into insoluble chloral. Lastly, the chloral is distilled over lime 
 which has been slaked and subsequently ignited, to remove hydrochloric acid, care 
 being taken to keep the whole of the lime below the surface of the liquid, as it will 
 otherwise decompose the vapour and become red-hot. In this manner the chloral 
 is obtained tolerably pure ; but it still contains traces of water and alcohol, which 
 
CHLORAL. 881 
 
 may be removed by repeated treatment with sulphuric acid, the chloral being each 
 time rectified over Hme. All these operations must be performed in well closed vessels. 
 (Liebig.) 
 
 2. By distilling starch or sugar with hydrochloric acid and peroxide of manganese 
 (Stadeler). 1 pt. of starch, or grape-sugar, or common sugar, is gently heated with 
 7 pts. of commercial hydrochloric acid free from sulphurous acid and diluted with an 
 equal volume of water, till the paste (formed when starch is used) has become fluid ; 
 the liquid, when cold, is introduced, together with 3 pts. of manganese and a small 
 quantity of common salt (to fix the sulphuric acid produced from the sulphurous acid 
 in the commercial hydrochloric acid) into a capacious flask, in which it is heated as 
 quickly as possible to the boiling point ; and the fire is then completely removed. The 
 mass swells up, giving off a large quantity of carbonic acid, and continues to boil 
 for some time by itself. As soon as the ebullition slackens, it must be kept up by 
 fresh application of heat, and the distillate collected, as long as it becomes turbid when 
 mixed with tolerably strong potash-ley (in consequence of separation of chloroform 
 from the chloral). More hydrochloric acid is then repeatedly introduced into the flask 
 by small portions, till the distillate no longer smells of chloral, or becomes turbid with 
 potash. The watery distillate is carefully freed from the colourless oil- drops, heavier 
 than water and smelling of chloroform, which are produced at the beginning of the 
 distillation ; and saturated with common salt, in order to raise its boiling point and 
 retain the water. It is then redistilled, and the resulting distillate is freed from a 
 sulphur-yellow very pungent oil, and distilled several times more with common salt, 
 the oily drops being each time removed, in order to obtain aqueous chloral as concen- 
 trated as possible, and as free as possible from the yellow oil, which greatly impedes 
 the purification. 
 
 The removal of this oil is facilitated by saturating the distillate, before each rectifi- 
 cation, with chalk, which decomposes the oil, but does not attack the chloral. The 
 concentrated solution of chloral is saturated with dry chloride of calcium, and dis- 
 tilled in an oil-bath at 120 C. Hydrate of chloral then passes over, as a colourless 
 liquid, which solidifies in the receiver into a crystalline mass. The last portions of 
 the distillate are contaminated with a brown oily substance. 1. From the hydrate 
 of chloral thus obtained, the anhydrous chloral may be separated by distillation, and 
 purified in the manner above described. (Stadeler.) 
 
 Properties. Chloral is a thin colourless oil, greasy to the touch, and making grease- 
 spots on paper, which, however, soon disappear. Specific gravity = T502 at 18 C., 1*518 
 at 0, 1-4903 at 22. Boils at 94-4 (Liebig) ; at 98*6 when the barometer stands at 
 760 mm. (Kopp), and distils without decomposition. Vapour-density = 5*13. It has a 
 peculiar pungent odour, and excites a copious flow of tears : its taste is greasy and slightly 
 astringent. It acts very strongly on the skin, especially when its boiling vapour comes 
 in contact therewith. It has no acid reaction, even when dissolved in water, and does 
 not precipitate a solution of silver. 
 
 Mixed with a small quantity of water, it becomes heated and solidifies, forming a 
 mass of crystals of hydrate of choral, C 2 HC1 S O.H 2 O : a larger quantity of water dis- 
 solves it, and the solution evaporated in vacuo deposits the hydrate of chloral in large 
 rhombic laminae. The hydrate volatilises gradually in the air, and distils without 
 decomposition when heated. Its vapour-density is 2'76. 
 
 Chloral dissolves also in alcohol and in ether. It absorbs chlorine gas without 
 further change, and readily dissolves iodine, bromine, sulphur, and phosphorus, especi- 
 ally when heated. The iodine-solution has a purple- colour. 
 
 Decompositions. 1. Chloral is under certain circumstances inclined to pass into 
 an isomeric insoluble modification (p. 64). 2. Anhydrous chloral distils, for the most 
 part unchanged, with strong sulphuric acid ; but when hydrate of chloral is heated 
 with that acid, part of the chloral distils over in the anhydrous state, while the rest is 
 converted into chloralide (p. 61), with evolution of hydrochloric and sulphurous 
 acids, and a trace of carbonic acid. This reaction serves for the detection of chloral 
 in liquids. The liquid, concentrated by several distillations over chloride of calcium, 
 is heated for some time, with six times its volume of strong sulphuric acid, to 125 C, 
 and diluted, after cooling, with six measures of water. Chloralide then separates out 
 mixed with carbonaceous particles ; and the mixture washed, pressed between paper, 
 exhausted with ether and evaporated, yields crystals of chloralide, which may be 
 further purified by heating with sulphuric acid and recrystallisation from ether. 
 3. Fuming nitric acid, if ultimately aided by heat, converts chloral into trichloracetic 
 acid : the same transformation is effected by a mixture of hydrochloric acid and 
 chlorate of potassium. 4. Anhydrous metallic oxides, such as baryta, strontia, lime, 
 cupric oxide, mercuric oxide, and peroxide of manganese, exert no action upon chloral, 
 when that liquid is distilled over them. If, however, in the distillation of chloral over 
 
 VOL. I. 3 L 
 
882 CHLORAL. 
 
 baryta, strontia or lime, a portion of the oxide is left dry, or if either of these snbstances 
 is heated in chloral vapour merely to 100, it becomes red-hot, and completely de- 
 composes the choral, with evolution of carbonic oxide, and formation of a metal- 
 lic chloride mixed with charcoal. 5. Alkalis, either in the form of solid hydrates 
 or of aqueous solutions, decompose chloral readily at ordinary temperatures, with 
 evolution of heat, converting it into formate of potassium and chloroform, and a portion 
 of the latter compound is further decomposed, yielding formate and chloride of potas- 
 sium : 
 
 C'HCl'O + KHO = CHKO 2 + CHOP. 
 
 Chloral. Formate Chloroform, 
 
 of potassium. 
 
 and CHOP + 4KHO = CHKO 2 + 3KC1 + 2H 2 0. 
 
 5. Vapour of chloral passed over red-hot iron yields carbonic oxide, and chloride 
 of iron mixed with charcoal. 6. Potassium, in contact with chloral, eliminates hydrogen, 
 and forms a resinous body from which water extracts potash and choride of potassium. 
 7. Chloral forms with ammonia a compound, which, like aldehyde-ammonia, reduces 
 silver in the specular form, and from which sulphydric acid throws down a sulphuretted 
 compound apparently analogous to thialdine (Stadeler, Ann. Ch. Pharm. cvi. 253). 
 8. Sulphydric acid gas passed through an aqueous solution of chloral separates 
 a sparingly soluble crystalline compound, which is probably analogous to acetyl-mer- 
 captan (p. 107). but decomposes much more easily, giving off sulphydric acid even 
 during drying (Stadeler). 9. By boiling hydrate of chloral with hydrocyanic 
 and hydrochloric acid, a syrupy acid is formed resembling lactic acid. These last 
 three reactions indicate a close analogy between chloral and aldehyde, which is further 
 strengthened by the fact that chloral forms crystalline compounds with acid sulphites 
 of alkali-metal. (Stadeler.) 
 
 Insoluble Chloral, Metachloral (Gm.viu. 235; Gerh.i. 671.) Chloral is con- 
 verted, under certain circumstances, into an isomeiic modification insoluble in water. 
 This change takes place spontaneously when chloral is preserved in a stoppered 
 bottle, or when it is placed in contact with a quantity of water not sufficient to con- 
 vert it into the hydrate. Metachloral thus prepared is pure, and has the same com- 
 position as chloral. It is also produced, mixed, however, with a little chloralide, 
 by the action of sulphuric acid upon chloral. A layer of the crude hydrate of chloral 
 obtained in the preparation of chloral from alcohol (p. 880), left in contact with 
 strong sulphuric acid, solidifies, in a few hours into a mass of insoluble chloral. Pure 
 chloral in contact with six times its volume of strong sulphuric acid, undergoes the 
 same transformation in the course of a night. The metachloral thus obtained may bo 
 purified from chloralide by pulverising, and washing it, first with water and then with 
 alcohol. 
 
 Metachloral is a white powder, greasy to the touch, and having a faint aromatic 
 odour. It volatilises slowly in the air or in vacuo. It is insoluble in water, alcohol, 
 and^ther. When perfectly dry, it is reconverted by heat into soluble chloral, at 180C, 
 according to Kolbe, above 200 according to Eegnault. Heated with sulphuric acid, 
 it partly distils over as soluble chloral, but a considerable portion is decomposed, 
 with formation of chloralide, and evolution of hydrochloric and sulphurous acids. By 
 fuming nitric acid, metachloral is, like chloral, converted into trichloracetic acid ; but it 
 is not attacked by a mixture of hydrochloric acid and chlorate of potassium. With 
 solutions of the caustic alkalis, it behaves like ordinary chloral, yielding an alkaline 
 formate and chloroform ; but the quantity of the latter is less as the alkali is more 
 concentrated. 
 
 CHI.ORA.Zi, ATCYXiXC. See CmORAMYLAL. ' 
 
 CHX.ORAXj, IVEESITIC. This name was applied by Kane (Fogg. Ann. xliv. 
 473) to a pungent vesicating liquid of specific gravity 1*33, and boiling at 71 C., 
 which is obtained by passing dry chlorine into acetone. Kane's analysis gives 56*8 
 per cent, chlorine ; Liebig found only 52*6 per cent. It is probably a mixture con- 
 taining two or more of the chloracetones (p. 29). 
 
 CHXiORAIi, PROPXOirXC. Hydride of Pcntachloropropione, C 3 CP0 2 .H. This 
 body is -found amongst the products obtained by distilling starch with a mixture of 
 hydrochloric acid and peroxide of manganese. On saturating the acid distillate with 
 chalk or carbonate of sodium, and rectifying over a small quantity of chloride of calcium, 
 thepropionic chloral passes over among the first portions, together with an oil. To 
 remove the latter, the rectified distillate is agitated several times with ice-cold water, 
 and the cold saturated solution is decanted and heated, th propionic chloral then 
 separating in heavy drops having a faint yellow colour. By diffusing these drops 
 through a small quantity of water, and exposing them to a temperature of C., 
 
CHLORALBIN CHLORALDEHYDES. 
 
 883 
 
 colourless tables are obtained, which may be purified from adhering oil by pressure 
 between bibulous paper. They consist of a hydrate containing 4 at. water : C 3 HCPO-. 
 4H 2 0. (Stadeler, Handw. d. Chem. Suppl. ii. 796.) 
 
 CHLORALBIN. C 6 H 6 C1 2 . A crystalline substance contained in trichlorophenic 
 acid prepared by passing chlorine through coal-tar. It is separated by treating the 
 crude acid with ammonia and alcohol, or better with ether, whereupon the chloralbin 
 remains in very white needles ; it may be further purified by dissolving it in boiling 
 ether. It is but sparingly soluble in boiling alcohol, and insoluble in alkalis. It boils 
 at 190 C., and crystallises on cooling in fern-like tufts. At a higher temperature, 
 it sublimes without alteration and crystallises in needles. It is not attacked by hot 
 nitric or sulphuric acid. (Laurent, Rev. scient. vi. 72.) 
 
 CHXtORAXiDZZHlTDlES. These compounds are aldehydes in which the hydrogen 
 is more or less replaced by chlorine, and may be regarded as derived from the cor- 
 responding acids by the substitution of 1 or more at. chlorine for an equivalent quantity 
 of peroxide of hydrogen HO, thus : 
 
 Chloraldehydes. Acids. 
 
 Acetic C 2 H 3 O.C1 C 2 H 3 O.HO 
 
 Trichloracetic 
 Nitric . 
 Sulphuric . 
 Phosphoric . 
 
 C 2 C1 3 O.C1 
 
 N0 2 .C1 
 
 (S0 2 )".CP 
 
 (poy.ci 3 
 
 C 2 C1 3 O.HO 
 
 N0 2 .HO 
 
 (S0 2 )".(HO) 2 
 
 (PO)"'.(HO) 3 
 
 The chloraldehydes are a more numerous class of compounds than the alde- 
 hydes themselves, including many compounds usually denominated oxychlorides, 
 e. g. oxychloride of phosphorus. They bear to their corresponding acids the same 
 relation that metallic chlorides bear to metallic hydrates. 
 
 The term chlor aldehyde is also specially applied to the second compound in the 
 above list, viz : 
 
 Chloride ofTrichloracetyl (^Perchlorinated Acetic Aldehyde, C 2 C1 4 = 
 C 2 CPO.CL This body, discovered by Malaguti (Ann. Ch. Phys. i. [2] xvi. 5); Grin, 
 ix. 218 ; Grerh. i. 756), is a constant product of the action of heat on the perchlorinated 
 ethylic (vinic) ethers. Thus: 
 
 C 4 C1 10 
 
 Perchlor. oxide 
 
 of ethyl. 
 
 C 3 C1 6 2 
 
 Perchlor. for- 
 mate of ethyl. 
 
 C 4 C1 8 2 
 Perchlor. ace- 
 tate of ethyl. 
 
 C'C1 4 
 
 C 2 C1 4 
 
 2C 2 C1 4 
 
 C 2 C1 6 . 
 
 Sesquichloride 
 of carbon. 
 
 COOP. 
 
 Oxychloride 
 
 of carbon. 
 
 = C 2 C1 4 + C 2 C1 6 
 
 CO 2 . 
 
 Perchlor. car- 
 bonate of ethyl. 
 C 6 C1 io 4 = 
 
 Perchlor. oxa- 
 late of ethyl. 
 
 2C 2 C1 4 + COC1 2 + CO. 
 
 It Is best prepared from perchlorinated oxide of ethyl, C 4 C1 I0 (the product ob- 
 tained by the continued action of chlorine in sunshine, on anhydrous ether). This 
 compound is resolved at 300 C. into chloride of trichloracetyl and trichloride of 
 carbon ; and by subjecting the mixture to repeated fractional distillation, the tri- 
 chloride of carbon is left behind, and the chloride of trichloracetyl is obtained pure. 
 The rectification must be continued till the distillate no longer shows any turbidity 
 when mixed with water. 
 
 Chloraldehyde is a transparent, colourless liquid, of specific gravity 1-603 at 18 C. 
 Boiling point 118. Vapour- density 6'32 (calc. 2 vol. 6'295). It gives off excessively 
 pungent vapours on exposure to the air, and when placed on the tongue, first excites a 
 sensation of dryness, then forms a white spot, and ultimately exerts a caustic action. 
 It reddens litmus after a few seconds. 
 
 It sinks in water, and gradually dissolves, forming a clear solution of hydrochloric 
 and trichloracetic acids : the same decomposition is produced by aqueous solutions of 
 the fixed alkalis : 
 
 C 2 C1 3 O.C1 + H 2 = HC1 + C 2 C1 S O.H.O. 
 
 When a small quantity of alcohol is poured upon it, great heat is evolved, and the 
 whole is quickly volatilised ; but if the chloraldehyde be slowly added to an excess of 
 
 3 L 2 
 
884 CHLORALIDE. 
 
 alcohol, gradual decomposition takes place, attended with but little rise of temperature, 
 the products being hydrochloric acid and trichloracetate of ethyl : 
 
 C 2 CPO.C1 + C 2 H 5 .H.O = HC1 + C 2 CPO.C 2 H 5 .0. 
 With ammonia it forms trichloracetamide (p. 22) ; 
 
 C 2 CPO.C1 + 2NH 3 = N.H 2 .C2CPO + NH 4 C1, 
 
 and with phosphoretted hydrogen, PH 3 , the analogous compound, chloracetyphide, 
 P.H 2 .C 2 C1 3 (p. 879). 
 
 CKZ.ORAI.XDZ:. C 5 H 2 Cl fi 3 . (Stadeler, Ann. Ch. Pharm. Ixi. 104. Kekule, 
 ibid. cv. 293.) A crystalline compound obtained by the action of sulphuric acid upon 
 hydrate of chloral. To prepare it, hydrate of chloral is gently heated with 4 to 6 
 times its volume of strong sulphuric acid, the mixture being well shaken, and then 
 distilled at a heat between 120 and 130 C., as long as unaltered choral continues to 
 pass over. This choral is reconverted into hydrate by addition of a little water, then 
 poured back, and the distillation is repeated till the greater part of the chloral is 
 decomposed. The sulphuric acid is then found to be covered with a colourless oily 
 liquid, which solidifies on cooling into a white crystalline crust. This mass is broken 
 up, the sulphuric acid is drained off, and the crystals are washed with water, till the 
 wash- water no longer reddens litmus ; they are then dried between bibulous paper, and 
 dissolved in ether, and the ethereal solution is mixed with | its volume of alcohol. 
 The chloralide then separates as the ether evaporates, in well-defined crystals, which 
 must be crystallised several times from a mixture of alcohol and ether, in order to free 
 them from an oily matter which adheres to them : According to Kekule (Ann. Ch. 
 Pharm. cv. 293), a purer and more abundant product is obtained by the action of 
 fuming sulphuric acid on hydrate of chloral. When chloral which has been once 
 distilled over ordinary sulphuric acid, is mixed with an equal volume of acid, a large 
 quantity of hydrochloric acid is evolved, and about one-third of the chloral is con- 
 verted into chloralide. Carbonic oxide is also given off abundantly, together with a 
 very small quantity of carbonic anhydride ; sulphurous anhydride occurs only towards 
 the end of the process. The oily distillate solidifies on cooling in a crystalline mass, 
 which may be purified by recrystallisation from boiling alcohol. 
 
 Kekul6 explains the formation of chloralide and the accompanying products by the 
 following equation : 
 
 3C 2 HC1 3 + IPO = C 5 H 2 C1 6 3 + 3HC1 + CO. 
 
 Stadeler, on the other hand, considers it improbable that the conversion of the chloral 
 into chloralide can be due to the action of water, inasmuch as fuming sulphuric acid 
 seems to act better than ordinary sulphuric acid. He supposes that a triple molecule 
 of chloral (insoluble chloral) splits up into chloralide and chloroform, according to the 
 equation : 
 
 3C 2 HCPO = C 5 H 2 CP0 3 + CHCP, 
 
 and attributes the evolution of carbonic oxide observed by Kekule, to the resolution 
 of a molecule of chloral into this gas and chloroform : 
 
 C 2 HCPO = CO + CHCP. 
 
 Chloralide is insoluble in water, and likewise in sulphuric acid. It dissolves sparingly 
 in cold alcohol, but easily in boiling alcohol and in ether. From a hot saturated al- 
 coholic solution, it is deposited in very delicate white needles ; from a mixture of 
 alcohol and ether, in stellate groups of rectangular prisms belonging to the monoclinic 
 system, with oblique terminal faces, and generally having their lateral edges truncated. 
 They are transparent and colourless, with a glassy lustre, and cleave with facility in a 
 direction parallel to the prismatic faces. Chloralide melts between 112 and 114 C. 
 to an oily liquid, emitting at the same time an odour like that of chloral : it solidifies 
 at 108 (Kekule). Chloralide burns at 200 (Stadeler); at 260 (Kekule) with 
 a bright flame, green at the edges. 
 
 The alcoholic solution of chloralide does not precipitate nitrate of silver, but on 
 adding a drop of ammonia, a precipitate is immediately formed, consisting of chloride 
 of silver. Chloralide immersed in aqueous potash, is resolved into chloroform and 
 formate of potassium; but if alcoholic solutions are used, the only products are formate 
 and chloride of potassium, these compounds being in fact produced by the action of 
 alcoholic potash upon chloroform. 
 
 The composition of chloralide has been variously stated by different chemists. Sta- 
 deler, who discovered it, assigned to it the formula C 5 H*C1 6 3 , which is confirmed by 
 the recent experiments of Kekule\ Gerhardt (Traite, i. 672) proposed the formula 
 C 6 H S C1 7 4 ; G-melin (Handbook, ix. 207) gave C 8 H 4 C1 10 5 , and in the Handwortcrbuch 
 dcr Chcmie, 2 te Aufl. i. 112, the formula C*HCP0 2 is assigned to this compound. 
 
CHLORALOIL CHLORATES. 885 
 
 The following table exhibits the calculated composition of chloralide, according to 
 the preceding formulae, as compared with the results of analysis : 
 
 Calculation according to : Analysis: 
 
 Stadeler. Gerhardt. Gtnelin. Handw. Stadeler. Kekule. 
 
 C 5 H 2 C1 6 S CPffCrO 4 C 8 H 4 C1 10 5 C 4 HCP0 8 
 
 mean mean 
 
 C . 18-61 18-50 17-98 18-55 18-64 81'64 
 
 H . . 0-62 0-77 0-39 075 0'77 0'72 
 
 Cl . 65-88 64-10 68-62 66-29 66-20 66'00 
 O . 14-89 16-63 12-44 J4;98^ 
 
 100-00 100-00 ibo-oo 
 
 CHIiORAIiOIIi. A product of the action of chlorine upon aloin (p. 148). 
 
 CHIiORALURIC ACID. An acid produced, together with other substances, by 
 the action of chlorous acid on uric acid. It crystallises in nacreous laminae ; forms 
 crystallisable salts with barium and lead, and a curdy precipitate with silver- salts. 
 It gave by analysis 27'3 per cent. C, 3-8 H, 28'1 N, and 11-4 Cl, numbers which 
 are approximately represented by the formula C 14 H 22 N 12 C1 2 U . (Schiel, Ann. Ch. 
 Pharm. cxii. 78.) 
 
 CHXiORAlVXYXiAXi. C 5 H 8 C10 (?) A heavy liquid produced by the action of 
 chlorine upon amylic alcohol (q. v.} 
 
 CHXiORANXXi. Syn. with PERCHLOROQUINONE, C 6 C1 4 0. (See QUINONE.) 
 
 CHXiORANXXiAMXC ACID. Syn. with DICHLOROQUINONAMIC ACID. (See 
 QUINONIC ACID). 
 
 CHLORANILAIVIIDE. Syn. with DiCHLOROQuiNONAMiDE. (See QUINONIC 
 ACID.) 
 
 CHIiORANIXiAMIVlOirE. Syn. with DlCHLOROQUINONAMATE OF AMMONIUM. 
 
 CHiiORATJILIC ACID. Syn. with DICHLOROQUINONIC ACID. (See QUINONIC 
 ACID.) 
 
 CHXiORANTXiIXtri:. Syn. with CHLOROPHENYLAMINE. (See PHENYLAMINE.) 
 
 CHX.ORAXTXSXC ACID. See ANISIC ACID (p. 302). 
 
 CHXiORASTROXiXTB. A mineral found on the shores of Isle Royale, Lake 
 Superior, in small rounded water-worn pebbles which have come from the trap. It 
 has a finely radiated or stellate structure, light bluish-green colour, and pearly lustre 
 slightly chatoyant on the rounded sides. Specific gravity 3'180. Hardness 5'5 6. 
 Analyses by Whitney : 
 
 SiO 2 A1 4 Fe 4 3 Ca 2 Na^ K 2 H 2 
 
 36-99 25-49 6-48 19-90 3*70 0'40 7'22 = 101-18 
 
 37-41 24-25 676 21-68 4-88 5-77 = 100-25 
 
 These numbers lead to the formula 
 
 ~r/fCa 2 O\ 2 < -| 9 r/fAl 4 3 \% q . 02 -| fiTT2O 
 3 LV|Na 2 oJ- Sl J + 2 LHFe 4 3 )- 3Sl J + 6 H ' 
 
 which, if M=Ca, Na and flt = f (Al, Fe), may be reduced to that of an orthosilicate, 
 (M%i 8 )Si 3 12 + 2aq. 
 
 The mineral gives off water when heated, and melts with intumescence before the 
 blowpipe to a greyish blebby glass. With borax it forms a transparent glass tinged 
 with iron; blue with cobalt solution. Dissolves in hydrochloric acid, with separation 
 of flocculent silica. (Dana, ii. 315.) 
 
 CHIiORATES. Chloric acid, HC10 3 , is monobasic and forms but one class of 
 salts, having the general formula MC10 3 or M 2 O.C1 2 5 . They are all soluble in water, 
 and are resolved by heat into oxygen and a metallic chloride. (See CHLORIC ACID 
 under CHLORINE, p. 910.) 
 
 CHLORATE OF ALUMINIUM is a deliquescent salt obtained by precipitating a 
 solution of silico-fluoride of aluminium with an equivalent quantity of potassium, and 
 evaporating the filtrate. (B erz el iu s.) 
 
 CHLORATE OF AMMONIUM is obtained by adding ammonia or the carbonate to 
 chloric acid ; by precipitating an earthy chlorate with carbonate of ammonium ; or by 
 adding finely divided chlorate of potassium by small portions to a solution of silico- 
 fluoride of ammonium, and filtering. It crystallises in slender needles, has a pungent 
 taste, explodes when heated, and sometimes, according to Mitscherlich, even at ordinary 
 temperatures. Dissolves easily in water and in alcohol. 
 
 CHLORATE OF BARIUM, BaCIO 3 . Prepared: 1. By saturating aqueous chloric acid 
 with baryta- water or carbonate of barium, a. A hot solution of chlorate of potassium 
 
 3 L 3 
 
886 CHLORATES. 
 
 is precipitated with hydrofluosilicic acid in slight excess, and the filtrate is saturated 
 with carbonate of barium, whereupon chlorate of barium dissolves, and a small quantity 
 of silico-fluoride of barium remains behind. The filtered solution yields crystals of 
 the chlorate by evaporation (Wheeler, Ann. Ch. Phys. [2] vii. 74). b. A solution 
 of 27 pts. chlorate of sodium in 54 pts. water is mixed with a solution of 38 pts. tar- 
 taric acid in 38 pts. water ; the mixture is thrown into double the quantity of absolute 
 alcohol ; and the liquid, after standing 24 hours, is filtered from the crystallised 
 tartrate of sodium, then saturated with carbonate of barium, &c. (Du flos, N. Br. Arch, 
 xxiii. 306.) c. Equivalent quantities of chlorate of potassium and acid tartrate of 
 ammonium (122'6 pts. of the former to 167 of the latter) are dissolved in the smallest 
 possible quantity of boiling water; the liquid, after the acid tartrate of potassium has 
 crystallised out, is mixed with an equal quantity of alcohol ; the filtrate decomposed by 
 boiling with carbonate of barium, &c. (L. Thompson, Jahresber. d. Chem. 1847 8, 
 p. 381.) 
 
 2. 33y passing chlorine into hot water in which baryta is partly suspended, partly 
 dissolved. Chloride and chlorate of barium are then formed, the greater part of the 
 chloride is suffered to crystallise out, and the rest is removed by adding phosphate of 
 silver to the solution, in the exact quantity required. (Chenevix, Vauquelin, 
 Gmeliris Handbook, ii. 161.) 
 
 Chlorate of barium forms hydrated prismatic crystals, 2BaC10 3 + H 2 0, belonging to 
 the monoclinic system. Ratio of orthodiagonal, clinodiagonal, and principal axis = 
 0-882 : 1 : 1/07. Inclination of axes = 85 30'; ooP : ooP in the orthodiagonal sec- 
 tion = 97; [P oo ] : [Po], in the clinodiagonal section =79 10'. Ordinary com- 
 bination coP . [P oo] . P co ; also without P co ; also with ooP GO (Kopp, Krystallo- 
 yraphie, p. 304), and less frequently with OP (Ramm els berg, Pogg. Ann. xc. 16). 
 The crystals are transparent and colourless, give off their water (47 '2 per cent.) at 
 120 C., oxygen at .250, and melt at a temperature above 400 (Wachter, Ann. 
 Ch. Pharm. lii. 231; Souchay, ibid. cii. 381). The salt detonates powerfully with 
 combustible bodies; produces a green flame when heated with sulphur (Duflos); and 
 emits a bright flashing light with strong sulphuric acid (Chenevix). It dissolves 
 easily in water, but is insoluble in alcohol. The anhydrous salt dissolves in 4-38 
 pts. of water at C., in 2'70 pts. at 20, in 1-92 pts. at 40, in 1-29 pts. at 60, in 
 1-02 pts. at 80, and in 079 pts. at 100 (Kremers, Jaheresber. d. Chem. 1856, 
 p. 274.) According to Hutstein (Arch. Pharm. [2] Ixxvii. 137) it emits light on 
 crystallising. 
 
 CHLORATE OF CALCIUM, CaC10 3 + H 2 0. Prepared like the barium-salt. Crys- 
 tallises in deliquescent rhomboidal prisms, easily soluble in water and alcohol. They 
 contain 16-5 p.c. water, melt in their water of crystallisation when gently heated, and 
 decompose at a higher temperature. (Gm. iii. 212.) 
 
 CHLORATE OF COBALT, CoCIO 3 + 3H 2 0. Crystallises in cubo-octahedrons. De- 
 composed by ignition into chlorine, oxygen, and a residue containing oxide and chloride 
 of cobalt. (Wachter, Ann. Ch. Pharm lii. 233.) 
 
 CHLORATE OF COPPER, CuC10 3 4 3H 2 0. A solution of cupric oxide in chloric 
 acid yields green deliquescent octahedrons having a slight acid reaction, and soluble 
 in alcohol. At 100 C. it gives off a few gas-bubbles, and at 260 suffers further 
 decomposition, leaving a residue which is insoluble in water but soluble in acids, and 
 appears to consist of a basic chlorate, inasmuch as its solution in nitric acid gives no 
 precipitate with silver-salts (Wachter, loc. tit.} Cupric chlorate detonates with bright 
 green flame on glowing coals, and is much used in pyrotechny for the production of 
 green fire. 
 
 CHLORATE OF LEAD, 2PbC10 3 + H*0. Rhomboidal prisms, which become dull 
 and opaque by exposure to the air ; soluble in water and alcohol but not deliquescent. 
 When heated, they leave oxychloride of lead containing Pb 6 Cl 4 0. (Wachter.) 
 
 CHLORATE OF LITHIUM, 2LiC10 3 + H 2 0. Radiated, very deliquescent mass, melting 
 at C., and giving off water at 140, together with oxygen and small quantities of 
 chlorine. Very soluble in alcohol. (Wachter.) 
 
 CHLORATE OF MAGNESIUM, MgC10 3 + 3H 2 0. Crystalline crust, easily soluble 
 in alcohol, melting at 40 C., and giving off its water at 120; (Chenevix, 
 Wachter.) 
 
 CHLORATE OF MANGANESE. Colourless, known only in solution. 
 
 CHLORATES OF MERCURY. The mercuric salt is obtained by dissolving mercuric 
 oxide in warm chloric acid (Vauquelin), or by heating mercuric oxide with succes- 
 sive portions of chlorine-water, filtering from mercuric oxychloride, and concentrating 
 the filtrate ; mercuric chloride then crystallises out, while the chlorate remains in 
 solution (Braamcamp and Siqueira.) Mercuric chlorate forms small deliquescent 
 
CHLORATES. 887 
 
 needles, which redden litmus, taste like the chloride, and are resolved by heat into 
 oxygen gas, mercurous chloride, calomel, and metallic mercury. The salt does not 
 deflagrate on red-hot coals, but sets fire to sulphide of antimony at ordinary tempera- 
 tures. (G-m. vi, 62.) 
 
 Mercurous Chlorate, Hg 2 O.C10 5 or HhgCIO 3 . A solution of mercurous oxide 
 in chloric acid yields the salt in beautiful prismatic crystals, which dissolve in water 
 and in alcohol, and are resolved by heat into oxygen, metallic mercury, and calomel. 
 (Wachter.) 
 
 CHLORATE OF NICKEL, NiCIO 3 -f 3JPO, crystallises in regular octahedrons of a 
 deep green colour, deliquescent and soluble in alcohol. When heated, they give olf 
 oxygen and chlorine, and leave a mixture of chloride and oxide of nickel ; at a very 
 strong red heat, however, nothing but oxide remains behind. (Wachter.) 
 
 CHLORATE OF POTASSIUM, KC10 3 , or KO.CIO*. This salt is an important 
 article of manufacture, being used in the preparation of lucifer matches and for other 
 purposes in the arts. It is prepared, either by passing chlorine into solution of potush 
 or carbonate of potassium, whereby chlorate and chloride of potassium are formed, 
 which are separated by crystallisation, the chlorate being much the less soluble of the 
 two ; or by decomposing chlorate of calcium with sulphate or chloride of potassium. 
 
 1. A solution of 1 pt. hydrate of potassium in 3 pts. water is saturated with chlo- 
 rine gas, whereby chloride and hypochlorite of potassium are produced, the liquid 
 acquiring strong bleaching properties : 
 
 2KHO + CP = KC10 4- KC1 + H 2 0. 
 
 The liquid is then left to itself for a day, or heated for some time to the boiling point, 
 whereby the hypochlorite is completely resolved into chloride and chlorate : 
 
 3KC10 = 2KC1 + KC10 S . 
 
 The ultimate result is to convert 6 at. hydrate of potassium, by the action of 6 at. 
 chlorine, into 1 at. KC10 3 and 5 at. KC1. It has been found that if a solution of 
 potash either stronger or weaker than that above mentioned be used, part of the 
 chlorate produced is decomposed into free oxygen and chloride of potassium. 
 
 The solution, when left to itself, deposits the greater part of the chlorate of potas- 
 sium in crystals, which may be purified from adhering chloride by recrystallisation. 
 The mother-liquor yields by concentration an additional quantity of chlorate, which, 
 however, is more contaminated with chloride, and requires a greater number of crystal- 
 lisations to purify it. The test of purity is that the solution is not clouded by a drop 
 of nitrate of silver. 
 
 Carbonate of potassium may be used for the preparation instead of caustic potash. 
 In that case a considerable quantity of acid carbonate of potassium is formed in the 
 early stage of the process, and crystallises on the sides of the vessels ; but on continuing 
 the passage of the chlorine, this salt is decomposed, with evolution of carbonic acid, 
 the ultimate products being chlorate and chloride of potassium as before. 
 
 Carbonate of potassium may also be used in the solid form, being laid on shelves or 
 trays in a chamber into which chlorine gas is introduced, just as in the manufacture 
 of bleaching powder. When the absorption of the chlorine is complete, the product 
 is dissolved in water, and the chlorate crystallises out, as above described. 
 
 2. Hypochlorite of calcium, or bleaching powder, the so-called " chloride of lime " 
 is made into a " cream " with water, and submitted to continuous boiling or evapora- 
 tion to dryness, whereby it is resolved into a mixture of chlorate and chloride of 
 calcium (p. 910), a change the completion of which is indicated by the loss of bleach- 
 ing properties in the mass. The residue, after evaporation, is treated with water, and 
 chloride or sulphate of potassium is added, whereby the chlorate of calcium is de- 
 composed, with production of chlorate of potassium and chloride or sulphate of calcium. 
 The chlorate, amounting to about ^ o f the weight of chloride of lime employed, is 
 separated from sulphate of calcium by the insolubility of the latter, or from chloride 
 of calcium by crystallisation. 
 
 The process now generally employed consists in a modification of the last, in which 
 the chloride of lime is formed in the same operation as the chlorate itself, instead of 
 starting from a previously manufactured bleaching powder. Excess of chlorine is 
 passed into a mixture of 300 pts. caustic lime and 154 of chloride of potassium with 
 100 water, the operation being performed in close leaden tanks, heated by steam and 
 provided with agitators. A man-lid, through which the tank can be cleansed or 
 repaired, and one or two wide tubes descending nearly to the bottom of the vessel, 
 through which materials can be introduced, complete the arrangement. During the 
 action, the temperature rises to about 200 F. After the completion of this operation, 
 
 3r 4 
 
888 
 
 CHLORATES, 
 
 the liquid is filtered and evaporated nearly to dryness by steam heat ; and the resulting 
 mass is redissolved in hot water and set to crystallise. 
 
 The whole of the chloride of calcium remains in the mother-liquors, and the crystals 
 of chlorate are rendered fit for the market by slight washing and draining. The reac- 
 tion upon which this operation depends is represented by the following equation : 
 
 KC1 + 3Ca 2 + 6C1 = KC10 3 + GCaCl. 
 
 In this process, 154 pts. KC1 give more than 200 pts. KC10 3 , while, by the method 
 of direct saturation, 115 pts. caustic potash yield only 30 pts. of that salt; at the 
 same time, no by-product is formed except chloride of calcium. The crystallisable 
 mother-liquors of this manufacture consist, within 1 or 2 per cent., entirely of this 
 salt, and may be decomposed either by an addition of sulphate of potassium or of car- 
 bonate of sodium. In the former case, sulphate of calcium is precipitated, avail- 
 able in the manufacture of paper, while chloride of potassium remains in solu- 
 tion, and may be recovered by evaporation, to be employed in the preparation of fresh 
 portions of chlorate: in the latter, carbonate of calcium, the "creta prsecipitata " of 
 the druggist, is precipitated, and is largely employed by the pharmaceutist and the 
 perfumer. Nearly the whole of the waste liquors of the English manufacturer are 
 converted into the latter product. 
 
 Carbonate instead of chloride of potassium may also be mixed with the quick lime : 
 in that case, on treating the mixture with water, after it has been exposed to the 
 action of chlorine, the whole of the lime remains as carbonate, while chloride and chlo- 
 rate of potassium are dissolved. (Grm. iii. 59, lire's Dictionary of Arts, Manufactures 
 and Mines, i. 66.) 
 
 Properties. Chlorate of potassium crystallises in anhydrous six-sided laminae, more 
 rarely in needles. The crystals belong to the monoclinic system. Katio of ortho- 
 diagonal, clinodiagonal, and principal axis = 1-360 : 1 : 0-804. Inclination of axes = 
 70 11'. Ordinary combination ooP . OP . +P. +2Poo; also twin-crystals. Cleav- 
 age parallel to ooP and OP. 
 
 Chlorate of potassium is but slightly soluble in cold water. The quantities dissolved 
 by 100 pts. of water at different temperatures, as determined by Gray-Lussac, are given 
 in the following table : 
 
 at 0C. . 
 15-37 . 
 24-43 
 35-02 
 
 3-3 pts. 
 6-03 
 8-44 
 12-05 
 
 at 49-06 C. . 
 74-39 . 
 104-78 
 
 . 18-98 pts. 
 . 85-40 
 . 60-24 , 
 
 It is insoluble in absolute alcohol. 
 
 Chlorate of potassium is permanent in the air at ordinary temperatures, but is 
 easily decomposed by heat, being at first resolved into chloride and perchlorate 
 of potassium, with a small quantity of free oxygen : 2KC10 3 = KC1 + KC10 4 + O 2 , 
 while at a higher temperature the whole of the oxygen is given off (39 '15 per cent. 
 of its weight in all), and chloride of potassium remains. 
 
 The decomposition is greatly facilitated by mixing the chlorate with peroxide of 
 manganese or oxide of copper, the whole of the oxygen of the chlorate being then 
 given off at a low red heat without previous formation of perchlorate : such a mix- 
 ture is very convenient for the evolution of oxygen. The metallic oxide does not 
 undergo any alteration, appearing to act merely by dividing the particles of the chlo- 
 rate and preventing them from fusing into a mass. 
 
 Chlorate of potassium is a powerful oxidising agent, and detonates violently when 
 mixed with certain combustible bodies and struck or heated. Triturated in a mortar 
 with flowers of sulphur, it produces a series of sharp detonations. A mixture of the 
 salt with sulphide of antimony takes fire when triturated, sometimes with explosion. 
 A small quantity of the chlorate' mixed with phosphorus and struck with a hammer 
 detonates with a loud report. These combustions are attended with great danger 
 when large quantities are used. 
 
 Chlorate of potassium is decomposed by acids, with evolution of peroxide of chlorine, 
 chlorous acid, or hypochlorous acid. With strong sulphuric acid, it is resolved into 
 peroxide of chlorine, perchlorate, and acid sulphate of potassium : 
 
 3KC10 3 + 2H 2 S0 4 = 2C10 2 + KC10 4 + 2KHS0 4 + H 2 
 
 The decomposition is attended with violent decrepitation, and sometimes with a flash- 
 ing light; combustible substances, such as sulphur, phosphorus, metallic sulphides, 
 arsenic, sugar, gum, resin, &c., are inflamed by the peroxide of chlorine evolved. A 
 finely-divided mixture of chlorate of potassium and excess of crystallised oxalic acid 
 heated to about 70 C. gives off peroxide of chlorine mixed with carbonic anhydride, 
 while chloride and acid oxalate of potassium remain (Calvert and Pa vies, Chem. 
 
CHLORATES. 889 
 
 Soc. Qu. J. xi. 193). The reaction probably takes place iii the manner represented by 
 the equation: 
 
 3KC10 8 + 6C 2 H 2 4 = 2C 2 KH0 4 + KC1 + 2C10 2 + 8C0 2 + 6H 2 0. 
 
 Chlorate of potassium boiled with strong nitric acid yields nitrate and perchlorate of 
 potassium, with evolution of chlorine and oxygen, but no peroxide of chlorine. 
 (Penny, J. pr. Chem. xxiii. 296): 
 
 8KC10 3 + 6HN0 3 = 6KN0 3 + 2KC10 4 + Cl 6 + O 13 + 3H 2 0. 
 
 Dilute nitric acid free from nitrous acid does not act on chlorate of potassium, even 
 when boiled ; but if it contains nitrous acid, or if any reducing agent is present, 
 such as tartaric acid, or arsenious acid, a lower oxide of chlorine is produced. 
 If the temperature be kept below 5 C. the chief product is chlorous acid, HC1O 2 , 
 the nitrous acid being at the same time reconverted into nitric acid : HNO 2 + HC10 3 
 = HNO 3 + HC10 2 (Millon, Ann. Ch. Pharm. xlvi. 298). Chlorate of potas- 
 sium heated with hydrochloric acid, yields chloride of potassium, and gives off a mix- 
 ture of peroxide of chlorine and free chlorine, called euchlorine, having the proportional 
 composition of hypochlorous anhydride (CIO 2 + Cl 3 = 2CFO). The reaction is : 
 
 4KC10 3 + 12HC1 = 4KC1 + 6H 2 + 3C10 2 + Cl 9 . 
 
 A mixture of chlorate of potassium and hydrochloric acid is much used as an oxidising 
 agent, e. g. for the destruction of organic matter in toxicological investigations. 
 
 Chlorate of potassium heated with pentachloride of phosphorus, gives off a deep yellow 
 gas which does not explode when heated, and when passed into dilute potash -ley, 
 forms chloride, chlorate, and hypochlorite of potassium (H. Schiff, Ann. Ch. Pharm. 
 cvi. 116). Chlorate of potassium distilled with iodine, gives off a chloride of iodine, 
 while chloride and iodate of potassium remain mixed with the excess of chlorate 
 (Wohler): 
 
 KC10 3 + I + I* = KIO 3 + I*C1. 
 
 lodic acid added to solution of chlorate of potassium, forms crystals of neutral or acid 
 iodate of potassium, while free chloric acid remains in solution. (Serullas.) 
 
 Chlorate of potassium is extensively used in the manufacture of lucifer matches and 
 fire-works. Lucifer matches which take fire by friction, are tipped with a mixture 
 of chlorate of potassium, phosphorus, and glue or gum. 
 
 Mixtures for producing fires of various colours, are composed as follows : 
 
 Red fire. Green fire. Purple fire. 
 
 Nitrate of strontium 40 pts. Nitrate of barium 77 pts. Oxide of copper 12 pts. 
 
 Chlorate of potassium 6 Chlor. of potassium 8 Chlor. potassium 30 
 
 Fine charcoal 2 Fine charcoal 3 
 
 Sulphur 13 Sulphur 13 Sulphur 12 
 
 The following composition is applied to the interior of percussion caps, in quantities 
 varying from 0-2 to 0'3 of a grain . Chlorate of potassium 26 pts., nitre 30, fulminate of 
 mercury 12, sulphur 17, ground glass 14, gum 1 ( = 100). 
 
 Chlorate of potassium is now extensively used as an oxidising agent in heightening 
 the intensity of steam-colours on printed goods. It is of constant use in the laboratory 
 as a source of oxygen, and is employed in medicine in the treatment of irritation of 
 the mucous membranes. For the manufacture of gunpowder it is not well adapted, 
 as the powder made with it, produces a very violent explosive force within a small 
 space only, and bursts the gun instead of propelling the ball. 
 
 CHLORATE OF SILVER, AgClO 3 . Obtained by dissolving oxide of silver in 
 chloric acid, or by passing chlorine through water in which the oxide is suspended, 
 filtering from chloride of silver, and evaporating. It crystallises in white opaque 
 four-sided prisms, with oblique terminal faces (Vauquelin), of specific gravity 4-430 
 (Schroder) ; tastes like the nitrate. It deflagrates brightly on hot coals, and when 
 mixed with sulphur, detonates violently on the slightest pressure. Hydrochloric, 
 nitric, and acetic acid, convert it into chloride, with evolution of oxygen. 
 ^ CHLORATE OF SODIUM, NaClO 3 . This salt maybe prepared by the action of chlo- 
 rine on solution of soda; but it is difficult to separate from the chloride formed at the 
 same time ; the separation might, however, be effected by alcohol, which dissolves the 
 chlorate much more easily than the chloride. The salt is likewise obtained by decom- 
 posing chlorate of potassium with silico-fluoride or acid tartrate of sodium, or chlorate 
 of ammonium by carbonate of sodium (Wittstein). It might also be prepared by 
 decomposing chlorate of calcium with carbonate of sodium. 
 
 Chlorate of sodium crystallises in regular tetrahedrons, modified by the faces of the 
 opposite tetrahedron, also of the cube and rhomboidal dodecahedron : the crystals are 
 
890 CIILORHYDRIC ACID. 
 
 isomorphous with those of bromate of sodium. They dissolve in 3 times their weight 
 of cold water, and in a smaller quantity of boiling water ; also in 34 pts. of 83 per cent, 
 alcohol at 16 C. and in a smaller quantity of hot alcohol. 
 
 CHLORATE OF STRONTIUM, SrCIO 3 . Prepared like the barium- salt. Crystallises 
 in deliquescent needles, or, according to Wachter, in large pyramidal crystals. It decom- 
 poses at the same temperature as the barium-salt, and deflagrates with purple flame 
 on glowing coals. 
 
 CHLORATE OF URANIUM. Protoxide of uranium dissolves in chloric acid, 
 forming a green solution, which decomposes spontaneously, with evolution of chlorine and 
 formation of uranic chloride. (Kammelsberg.) 
 
 CHLORATE OF ZINC, ZnCIO 3 + 3H 2 0, is obtained by dissolving carbonate of zinc 
 or metallic zinc in chloric acid, chloride of zinc being also formed in the latter case ; also 
 bypassing gaseous fluoride of silicon into water in which carbonate of zinc is suspended, 
 and boiling the filtered liquid with chlorate of potassium. It crystallises, apparently, 
 in octahedrons, has a very rough taste, and is soluble in water and alcohol. 
 
 CHIiORETHERAIi. Syn. with MoNOCHLORETHYLic ETHER. See ETHYL, 
 OXIDE OF (ii. 643). 
 
 CHLORHYDRIC or HYDROCHLORIC ACID. II CL This gas is the only 
 known compound of chlorine and hydrogen. Its solution in water has been used from 
 very early times, and has received the names of spirit of salt, muriatic acid, hydro- 
 chloric acid, and chlorhydric acid. The gas was discovered by Priestley in 1772. 
 
 Natural Sources. Hydrochloric acid gas is evolved from volcanos in eruption, 
 and the acid solution is sometimes found in crevices on their slopes. It exists also, 
 to the amount of 1 or 2 pts. in a thousand, in certain rivers of South America 
 which have their source in volcanic formations. 
 
 Formation and Preparation. 1. Hydrochloric acid is produced by the direct union of 
 chlorine and hydrogen. A mixture of the two gases in equal volumes, explodes 
 violently if a burning body is introduced into it, or an electric spark passed through 
 it, or if it be exposed to direct sunshine (Gm. ii. 319). No combination takes place 
 in the dark, but if the mixture be exposed to diffused daylight, the gases combine 
 gradually. Thus, if two bottles of exactly equal capacity and fitted to one another by 
 grinding, are filled by displacement with chlorine and hydrogen respectively, then 
 adapted to each other by their mouths, the chlorine-vessel being placed uppermost, 
 and set aside for some hours in a light situation, but not in direct sunshine, the green 
 colour of the chlorine will gradually disappear almost entirely, and a few minutes' 
 exposure to sunshine will complete the combination. If the two bottles be then sepa- 
 rated under mercury, each will be found full of hydrochloric acid gas, no gas escaping 
 and no rising of the mercury taking place in either bottle, showing that the chlorine 
 and hydrogen have combined without expansion or contraction. If a jet of water 
 tirsged with blue litmus be thrown up into either of the bottles, the gas will be rapidly 
 and completely absorbed, while the litmus solution will assume a bright red colour. 
 Any bleaching of the litmus would indicate free chlorine ; any unabsorbed gas, the 
 presence of free hydrogen ; in this manner, an excess of either gas in the original 
 mixture may be detected. 
 
 2. Hydrochloric acid gas is usually prepared by the action of sulphuric acid on fused 
 chloride of sodium. There is at first a copious effervescence, which, after some time, 
 it may be necessary to revive by the application of a gentle heat. The reaction is : 
 
 NaCl + H 2 S0 4 = NaHSO 4 + HC1. 
 
 The gas must be collected over the mercurial trough, as it is rapidly absorbed by 
 water. 
 
 3. Hydrochloric acid may also be produced by the action of water on certain 
 chlorides. The two chlorides of phosphorus are decomposed immediately and com- 
 pletely by mixture with an excess of water, with formation of phosphorous and phos- 
 phoric acid respectively, thus : 
 
 PCI 3 + 3H 2 = H'PO 3 + 3HC1. 
 
 PCI 5 + 4H 2 = H 9 P0 4 + 5HC1. 
 
 The two chlorides of antimony are decomposed more slowly. Trichloride of bismuth 
 requires prolonged treatment with water to effect its thorough decomposition, which, 
 however, takes place readily at a boiling temperature. Stannic chloride, even at a 
 boiling temperature, is decomposed very imperfectly. The sesquichloride of aluminium 
 and protochloride of magnesium, &c., are decomposed by steam, with evolution of 
 hydrochloric acid, at temperatures considerably below redness : 
 
 2AFC1 3 + 3H 2 = Al'O 3 + 6HC1. 
 2MgCl + H 2 = Mg 2 O + 2HCL 
 
CHLORHYDRIC ACID. 891 
 
 Moreover, hydrochloric acid results from the reaction of chloride of phosphorus, 
 chloride of antimony, and some other chlorides, usually hyperchlorides, not only with 
 water, but with most oxyhydrogenised compounds (pp. 897 900). 
 
 4. Hydrochloric acid is a constant attendant upon the direct action of chlorine on 
 hydrogenised substances. A solution of chlorine in water is converted, when exposed 
 to light, into hydrochloric and hypochlorous acids : Cl 2 + IPO HC1 -f HC10. Chlorine 
 instantly decomposes sulphydric acid, with formation of hydrochloric acid and separa- 
 tion of sulphur : Cl 2 + H 2 S = 2HC1 + S. Phosphoretted and arsenetted hydrogen are 
 likewise decomposed by chlorine, with formation of hydrochloric acid. Numerous 
 organic compounds also are decomposed by chlorine, one portion of that element 
 uniting with the whole or with part of the hydrogen, and an equal portion taking the 
 place of the hydrogen thus removed : e. g. 
 
 C 2 H 4 2 + 3C1 2 = C 2 HC1 3 8 + 3HC1. 
 
 Acetic Trichlor- 
 
 acid. acetic 
 
 acid. 
 
 Hydrochloric acid also results from the inverse action of hydrogen upon a chlorine 
 compound, as when ignited chloride of nickel is subjected to a current of hydrogen, 
 thus: NiCl + H = HC1 + Ni. 
 
 Properties. Hydrochloric acid is a colourless gas, having a strong acid taste, and 
 a pungent irritating odour. Its specific gravity (air = 1) is, according to the deter- 
 mination of Biot and Gray-Lussac, 1/27; by calculation, it is x 0-0693 = 1 '265. 
 
 It forms opaque white fumes in the air, owing to its union with, and condensation of, the 
 atmospheric moisture. In perfectly dry air these fumes are not produced. The gas is 
 extremely soluble in water. When a flask of dry hydrochloric acid is opened under 
 water, the whole of the gas is absorbed in an instant, and the flask not unfrequently 
 broken by the violent rush of liquid. At mean temperature (15 C.) water dissolves 
 about 458 times its volume of the gas (see GASES, ABSORPTION OF). At the tempe- 
 rature of 10, under a pressure of 40 atmospheres, hydrochloric acid is condensed into 
 a colourless liquid, having a specific gravity T27. It has never been solidified. Hy- 
 drochloric acid is not inflammable, and extinguishes most burning bodies, but when a 
 piece of potassium is introduced by means of an iron wire into a tube full of the gas 
 retained over mercury, and is then heated to redness by a spirit-lamp applied exter- 
 nally, it undergoes combustion, unites with the chlorine, and leaves the hydrogen, 
 which is eventually found to occupy exactly one half the volume of the original gas : 
 HC1 + K = KC1 + H. 
 
 Solution of hydrochloric acid is usually made from common salt and sulphuric acid 
 diluted with about two-thirds its bulk of water. The reaction is effected in a retort 
 to which a gentle heat is applied, and the evolved gas is condensed in a vessel or 
 series of vessels of distilled water. The condensing liquid increases considerably in 
 bulk, and may eventually be made to acquire a specific gravity of 1*21, under which 
 circumstances it consists of one atom of hydrochloric .acid, HC1, dissolved in three atoms 
 of water, H 2 0. Solution of hydrochloric acid has usually a specific gravity of 1'162, 
 and then consists of one atom of hydrochloric acid HC1, dissolved in four atoms of 
 water, H 2 0. 
 
 Commercial muriatic acid is made by heating in iron cylinders two proportions of 
 common salt, with as much brown sulphuric acid as contains one proportion of 
 real acid, and condensing the evolved gas in water contained in a series of stoneware 
 Woulfe's bottles. The reaction is : H 2 SO 4 + 2NaCl = Na 2 S0 4 + 2HC1. For details, 
 see Ure' s Dictionary of Arts, Manufactures and Mines, ii. 481. Pelouze et Fre"my, 
 Traite de Chimie generate, 3 ma ed. i. 436. Pay en, Precis de Chimie industrielle, 4 me ed. 
 i. 264.) 
 
 The commercial acid, which frequently contains, as impurities, sulphurous acid, 
 arsenious acid, sesquichloride of iron, stannic chloride, and even free chlorine, may 
 be partly purified by dilution and redistillation. A pure solution of hydrochloric acid 
 is usually colourless, but when in large quantities, has a very pale yellowish green tint. 
 The slight yellow colour of miscalled pure acid is generally due to the presence of 
 free chlorine, but the bright deep yellow of the commercial acid results from the 
 presence of cfroride of iron. The introduction of a small quantity of organic matter, 
 as by contact with a cork, will likewise impart a yellow colour to hydrochloric ucid 
 otherwise pure. 
 
 A strong solution of hydrochloric acid evolves fumes on exposure to air. When 
 boiled, it gives off hydrochloric acid gas, until the temperature slightly exceeds 100 C., 
 when there distils over a diluted solution of the acid, having a specific gravity of I'l, 
 and consisting of 1 atom of hydrochloric acid, II Cl, dissolved in 8 atoms of water, H 2 0. 
 
892 
 
 CHLORHYDRIC ACID. 
 
 From the experiments of Roscoe, however (Chem. Soc. Qu. J. xiii. 156), it appears 
 that the composition of aqueous hydrochloric acid (and of other aqueous acids), of 
 constant boiling point, varies with the pressure, and that there exists for each pres- 
 sure a corresponding aqueous acid, which undergoes no change in composition when 
 distilled under this pressure, and therefore has a constant boiling point. In table A, 
 column P shows the pressure in metres of mercury under which aqueous hydrochloric 
 acid must be distilled to attain the composition given in the next column. 
 
 TABLE A. Percentage of HC1 in aqueous Hydrochloric Acid boiling under different 
 
 Pressures. 
 
 P 
 
 Percentage 
 of HC1. 
 
 P 
 
 Percentage 
 of HCI. 
 
 P 
 
 Percentage 
 of HCI. 
 
 P 
 
 Percentage 
 ot HCI. 
 
 0-05 
 
 23-2 
 
 0-7 
 
 20-4 
 
 1-3 
 
 19-3 
 
 2-0 
 
 18-5 
 
 o-i 
 
 22-9 
 
 076 
 
 20-14 
 
 1-4 
 
 19-1 
 
 2-1 
 
 18-4 
 
 0-2 
 
 22-3 
 
 0-8 
 
 20-2 
 
 1-5 
 
 19-0 
 
 2-3 
 
 18-3 
 
 0-3 
 
 21-8 
 
 0-9 
 
 19-9 
 
 1-6 
 
 18-9 
 
 2-4 
 
 18-1 
 
 0-4 
 
 21-4 
 
 1-0 
 
 197 
 
 17 
 
 18-8 
 
 2-5 
 
 18-0 
 
 0-5 
 
 21-1 
 
 1-1 
 
 19-5 
 
 1-8 
 
 187 
 
 
 
 0-6 
 
 207 
 
 1-2 
 
 19-4 
 
 1-9 
 
 18-6 
 
 
 
 The acid which boils constantly under the pressure 076 met., and contains 20-24 
 per cent. HCI, is the hydrate above mentioned, HCl.SH'O. The table shows that the 
 percentage of HCI in the aqueous acid of constant boiling point, diminishes with in- 
 crease of pressure. 
 
 When aqueous hydrochloric acid is vaporised by passing a current of dry air through 
 it at a given temperature, a point is likewise reached beyond which no decomposition 
 occurs. In Table B the first column gives the temperatures, the second the percentage 
 of HCI contained in the acid, unalterable at the corresponding temperature. 
 
 TABLE B. Percentage of HCI in Aqueous Hydrochloric Acid of constant c 
 at different Temperatures. 
 
 T o 
 
 Percentage of 
 HCI. 
 
 T 
 
 Percentage of 
 HCI. 
 
 T o 
 
 Percentage of 
 HCI. 
 
 T o 
 
 Percentage 
 of HCI. 
 
 0C. 
 
 25-0 
 
 30 C. 
 
 24-1 
 
 60 C. 
 
 23-0 
 
 90 C. 
 
 21-4 
 
 5 
 
 24-9 
 
 35 
 
 23-9 
 
 65 
 
 22-8 
 
 95 
 
 21-1 
 
 10 
 
 247 
 
 40 
 
 23-8 
 
 70 
 
 22-6 
 
 100 
 
 207 
 
 15 
 
 24-6 
 
 45 
 
 23-6 
 
 75 
 
 22-3 
 
 
 
 20 
 
 24-4 
 
 50 
 
 23-4 
 
 80 
 
 22-0 
 
 
 
 25 
 
 24-3 
 
 55 
 
 23-2 
 
 85 
 
 217 
 
 
 
 The specific gravity of aqueous hydrochloric acid, of various degrees of concentration 
 has been determined by Ure and by E. Davy. The results are given in Tables C 
 and D ; it will be observed that the specific gravities as determined by Davy are 
 rather lower for each percentage of HCI than those of Ure. 
 
 TABLE C. Percentage of HCI in Aqueous Hydrochloric Acid at 25 C. (77 F.) 
 according to E. Davy. 
 
 Sp. Gr. 
 
 HCI. 
 
 Sp. Gr. 
 
 HCI. 
 
 Sp. Gr. 
 
 HCI. 
 
 Sp. Gr. 
 
 HCI. 
 
 1-21 
 
 42-43 
 
 16 
 
 32-32 
 
 1-11 
 
 22-22 
 
 1-06 
 
 12-12 
 
 1-20 
 
 40-80 
 
 15 
 
 30-30 
 
 1-10 
 
 20-20 
 
 1-05 
 
 10-10 
 
 1-19 
 
 38-38 
 
 14 
 
 28-28 
 
 1-09 
 
 18-18 
 
 1-04 
 
 8-08 
 
 1-18 
 
 36-36 
 
 13 
 
 26-26 
 
 1-08 
 
 16-16 
 
 1-03 
 
 6-06 
 
 1-17 
 
 34-34 
 
 12 
 
 24-24 
 
 1-07 
 
 14-14 
 
 1-02 
 
 4-04 
 
 
 
 
 
 
 
 1-01 
 
 2-02 
 
CHLORHYDRIC ACID CHLORHYDRTNS. 893 
 
 TABLE D. Composition of Aqueous Hydrochloric Acid according to Ure. 
 
 Acid 
 of S P . 
 gr. 1'2. 
 
 Specific 
 Gravity. 
 
 Chlo- 
 rine, 
 per cent 
 
 HCl. 
 
 per cent. 
 
 Acid 
 
 of sp. 
 gr. 1 2. 
 
 Specific 
 Gravity. 
 
 Chlo- 
 rine, 
 per cent. 
 
 HCl. 
 
 per cent. 
 
 Acid 
 
 of sp. 
 gr.1'2. 
 
 Specific 
 Gravity. 
 
 Chlo- 
 rine, 
 per cent 
 
 HCl. 
 per cent. 
 
 100 
 
 1-2000 
 
 39-675 
 
 40-777 
 
 66 
 
 1-1328 
 
 26-186 
 
 26-913 
 
 32 
 
 1-0637 
 
 12-697 
 
 13-049 
 
 90 
 
 1-1982 
 
 39-278 
 
 40-369 
 
 65 
 
 1-1308 
 
 25-789 
 
 26-505 
 
 31 
 
 1-0617 
 
 12-300 
 
 12-641 
 
 98 
 
 1-1964 
 
 38-882 
 
 39-961 
 
 64 
 
 1-1287 
 
 25-392 
 
 26-098 
 
 30 
 
 1-0597 
 
 11-903 
 
 12233 
 
 97 
 
 1-1946 
 
 38-485 
 
 39-554 
 
 63 
 
 1-1267 
 
 24-996 
 
 25-690 
 
 29 
 
 1-0577 
 
 11-506 
 
 11-825 
 
 96 
 
 1-1928 
 
 38-089 
 
 39-146 
 
 62 
 
 1-1247 
 
 24-599 
 
 25-282 
 
 28 
 
 1-0557 
 
 11-109 
 
 11-418 
 
 95 
 
 1-1910 
 
 37-692 
 
 38-738 
 
 61 
 
 1-1226 
 
 24-202 
 
 24-874 
 
 27 
 
 1-0537 
 
 10-712 
 
 11-010 
 
 94 
 
 1-1893 
 
 37-296 
 
 38-330 
 
 60 
 
 1-1206 
 
 23-805 
 
 24-466 
 
 26 
 
 1-0517 
 
 10-316 
 
 10-602 
 
 93 
 
 1-1875 
 
 36-900 
 
 37-923 
 
 59 
 
 1-1185 
 
 23-408 
 
 24-058 
 
 25 
 
 1-0497 
 
 9-919 
 
 10-194 
 
 92 
 
 1-1857 
 
 36-503 
 
 37-516 
 
 58 
 
 1-1164 
 
 23-012 
 
 23-050 
 
 24 
 
 1-0477 
 
 9-522 
 
 9-786 
 
 91 
 
 1-1846 
 
 36-107 
 
 37-108 
 
 57 
 
 1-1143 
 
 22-615 
 
 23-242 
 
 23 
 
 1-0457 
 
 9-125 
 
 9-379 
 
 90 
 
 1-1822 
 
 35-707 
 
 36-700 
 
 56 
 
 1-1123 
 
 22-218 
 
 22-834 
 
 22 
 
 1-0437 
 
 8-729 
 
 9-971 
 
 89 
 
 1-1802 
 
 35-310 
 
 36-292 
 
 55 
 
 1-1102 
 
 21-822 
 
 22-426 
 
 21 
 
 1-0417 
 
 8-332 
 
 8-563 
 
 88 
 
 1-1782 
 
 34-913 
 
 35-884 
 
 54 
 
 1-1082 
 
 21-425 
 
 22-019 
 
 20 
 
 1-0397 
 
 7-935 
 
 8-155 
 
 87 
 
 1-1762 
 
 34-517 
 
 35-476 
 
 53 
 
 1061 
 
 21-028 
 
 21-611 
 
 19 
 
 1-0377 
 
 7-538 
 
 7-747 
 
 86 
 
 1-1741 
 
 34-121 
 
 35-068 
 
 52 
 
 1041 
 
 20-632 
 
 21-203 
 
 18 
 
 1-0357 
 
 7-141 
 
 7-340 
 
 85 
 
 1-1721 
 
 33-724 
 
 34-660 
 
 51 
 
 1020 
 
 20-235 
 
 20-796 
 
 17 
 
 1-0337 
 
 6-745 
 
 7-932 
 
 84 
 
 1-1701 
 
 33-328 
 
 34-252 
 
 50 
 
 1000 
 
 19-837 
 
 20-388 
 
 16 
 
 1-0318 
 
 6-348 
 
 6-524 
 
 83 
 
 1-1681 
 
 32-931 
 
 33-845 
 
 49 
 
 0980 
 
 19-440 
 
 19-980 
 
 15 
 
 1-0298 
 
 5-951 
 
 6-116 
 
 82 
 
 1-1661 
 
 32-535 
 
 33-437 
 
 48 
 
 0960 
 
 19-044 
 
 19-572 
 
 14 
 
 1-0279 
 
 5-554 
 
 6-709 
 
 81 
 
 1-1641 
 
 32-136 
 
 33-029 
 
 47 
 
 0939 
 
 18-647 
 
 19-165 
 
 13 
 
 1-0259 
 
 5-158 
 
 5-301 
 
 80 
 
 1-1620 
 
 31-746 
 
 32-621 
 
 46 
 
 0919 
 
 18-250 
 
 18-757 
 
 12 
 
 1-0239 
 
 4-762 
 
 5-893 
 
 79 
 
 1-1599 
 
 31-343 
 
 32-213 
 
 45 
 
 0899 
 
 17-854 
 
 18-359 
 
 11 
 
 1-0220 
 
 4-365 
 
 4-486 
 
 78 
 
 1-1578 
 
 30-946 
 
 31-805 
 
 44 
 
 0879 
 
 17-457 
 
 17-941 
 
 10 
 
 1-0200 
 
 3-968 
 
 4-078 
 
 77 
 
 1-1557 
 
 30-550 
 
 31-398 
 
 43 
 
 1-0859 
 
 17-060 
 
 17-534 
 
 9 
 
 1-0180 
 
 3-571 
 
 4-670 
 
 76 
 
 1-1536 
 
 30-153 
 
 30-990 
 
 42 
 
 1-0838 
 
 16-664 
 
 17-126 
 
 8 
 
 1-0160 
 
 3-174 
 
 3-262 
 
 75 
 
 1-1515 
 
 29-757 
 
 30-582 
 
 41 
 
 1-0818 
 
 16-267 
 
 16-718 
 
 7 
 
 1-0140 
 
 2-778 
 
 3-854 
 
 74 
 
 1-1494 
 
 29-361 
 
 30-174 
 
 40 
 
 1-0798 
 
 15-870 
 
 16-310 
 
 6 
 
 1-0120 
 
 2-381 
 
 3-447 
 
 73 
 
 1-1473 
 
 28-964 
 
 39-767 
 
 39 
 
 1-0778 
 
 15-474 
 
 15-902 
 
 5 
 
 1-0100 
 
 1-984 
 
 2-039 
 
 72 
 
 1-1452 
 
 28-567 
 
 29-359 
 
 38 
 
 1-0758 
 
 15-077 
 
 15-494 
 
 4 
 
 1-0080 
 
 1-588 
 
 2-631 
 
 71 
 
 I 1431 
 
 28-171 
 
 28-951 
 
 37 
 
 1-0738 
 
 14-680 
 
 15-087 
 
 3 
 
 1-0060 
 
 1-191 
 
 1-224 
 
 70 
 
 1 1410 
 
 27-772 
 
 28-544 
 
 36 
 
 1-0718 
 
 14-284 
 
 14-679 
 
 2 
 
 1-0040 
 
 0-795 
 
 1-816 
 
 69 
 
 11389 
 
 27-376 
 
 28-136 
 
 35 
 
 1-0697 
 
 13-887 
 
 14-271 
 
 1 
 
 1-0020 
 
 0-397 
 
 1-408 
 
 68 
 
 1-1369 
 
 26-979 
 
 27-728 
 
 34 
 
 1-0677 
 
 13-490 
 
 13-863 
 
 
 
 
 
 67 
 
 1-1349 
 
 26-583 
 
 27-321 
 
 33 
 
 1-0657 
 
 13-094 
 
 13-456 
 
 
 
 
 i 
 
 Aqueous hydrochloric acid possesses powerful acid properties, reddens litmus, tastes 
 intensely sour, effervesces with carbonates, and dissolves many metals with evolution 
 of hydrogen. It does not bleach vegetable colours or dissolve gold leaf. W. O. 
 
 CHXiORHYDRXC ETHERS. See CHLORIDES OF ALCOHOL-EADICLES (p. 897). 
 
 CHX.ORKYDRINS. (Berthelot, Ann. Ch. Phys. [3] xli. 296. Berthelot 
 and De Luca, ibid, xlviii. 304; lii. 433.) These compounds, which are precisely 
 analogous to the bromhydrins (p. 667), are the chlorhydric ethers of glycerin, and may 
 be regarded as derived therefrom by the substitution of one or more atoms of chlorine 
 for an equivalent quantity of peroxide of hydrogen. They are produced, either by 
 the action of hydrochloric acid or of the chlorides of phosphorus on glycerin ; the 
 latter method does not however yield very good products. 
 
 Monochlorkydrin^C 3 H 7 C\0* =- (C 3 H 5 )'".(HO) 2 .C1, is obtained by saturating 
 gently heated glycerin with hydrochloric acid gas ; then keeping the liquid at 100 C. for 
 some hours ; saturating with carbonate of sodium ; agitating with ether ; distilling the 
 residue left after evaporation of the ether ; and again treating it with carbonate of 
 sodium and ether. It is a neutral oil, having a fresh ethereal odour and a sweet taste, 
 with pungent after-taste. Specific gravity 1-31. It remains perfectly fluid at 35 C. ; 
 boils at 227 ; burns with a white, green-edged flame, emitting 'hydrochloric acid. 
 Oxide of lead saponifies it slowly. It does not immediately precipitate nitrate of 
 silver. It mixes with its own bulk of water. With 8 or 10 times its bulk of water, it 
 forms a very stable emulsion. It also mixes with ether. 
 
 DicUorhydrin, C 3 H 6 C1 2 = (C S H 5 )'".HO.C1 2 , is obtained by heating a solution of 
 glycerin in 10 or 12 times its weight of fuming hydrochloric acid, to 100 C. for three 
 or four days, purifying the product with carbonate of sodium and ether as above, and 
 
894 CHLORHYDROPHENIDE CHLORIDES. 
 
 evaporating, first over the water-bath, then in vacuo. It is a neutral oil, having an 
 ethereal odour. Specific gravity T37. It boils at 178 C. ; remains quite fluid at 35 ; 
 burns like the preceding ; is easily decomposed by potash, yielding chloride of potas- 
 sium and glycerin ; mixes with ether, but does not form a stable emulsion with water. 
 
 Trichlorhydrin; Trichloride of Glyccryl, C 3 H 5 CP. Produced by the action of 
 pentachloride of phosphorus on dichlorhydrin : 
 
 C 3 H 6 C1 2 + PCI 5 = PCPO + HC1 + C 3 H 5 C1 8 . 
 
 It is a neutral liquid, much more stable than tribromhydrin. Volatilises at about 
 155 C. (Berthelot andDeLuca.) 
 
 Epichlorhydrin. Oxychloride of Glyceryl. C 3 H 5 C10. Obtained by treating di- 
 chlorhydrin with hydrochloric acid gas, or with the fuming acid. Neutral oil, re- 
 sembling dichlorhydrin. Distils between 120 and 130 C. (Berthelot.) 
 
 Epidichlorhydrin. Bichloride of Glycerylene. C 3 H 4 CP. Produced in small 
 quantity in the preparation of trichlorhydrin and bromodichlorhydrin, probably by a 
 secondary reaction, inasmuch as it differs from dichlorhydrin by H 2 0, and from tri- 
 ehlorhydrin by HC1. It is isolated and purified by repeated fractional distillation. 
 Neutral liquid, volatile at about 120 C. Treated with moist oxide of silver, it slowly 
 reproduces glycerin. (Berthelot and De Luca.) 
 
 Dibromochlorhydrin, C 3 H 5 Br' 2 Cl. Produced by the action of pentachloride of 
 phosphorus on dibromhydrin. Neutral liquid, volatile at about 200 C. With moist 
 oxide of silver at 100, it slowly reproduces glycerin. It is isomeric with dibromide 
 of chlorotritylene, C 3 H 5 ClBr 2 . 
 
 Bromodichlorhydrin, C 8 H 5 BrCl 2 . Produced by the action of pentabromide of 
 phosphorus on dichlorhydrin. Neutral liquid, volatile at about 176 C. Isomeric with 
 dichloride of bromotritylene. 
 
 With moist oxide of silver at 100, it slowly reproduces glycerin ; at the same time, 
 however, a small quantity of carbonic anhydride is formed by oxidation, together with 
 crystalline scales, which appear to be propionate of silver : 
 
 C 3 H 5 BrCl 2 + 3H 2 = C S H 8 3 + 2HC1 + HBr 
 
 Glycerin. 
 
 and C 3 H 5 BrCl 2 + 2H 2 = C 3 H 6 2 + 2HC1 + HBr 
 
 Propionic 
 acid. 
 
 For the ACETOCHLORHYDKINS, see p. 25 ; BENZOCHLOBHYDRINS (p. 547.) 
 CHLORHYDROPHENIDE. Chloride of Phenyl. (See PHENYL.) 
 CHXiORHlTDROPROTEXC ACID. A name applied by Mulder (J. pr. Chem. 
 xvii. 316), to the precipitate formed by hydrochloric acid in a solution of albumin, said 
 by Mulder to contain 37 per cent, of hydrochloric acid. It is probably however 
 nothing but albumin. 
 
 CHLORIDES. The term chloride is applied to all compounds of chlorine which 
 may be derived from one or more atoms of hydrochloric acid, H n Cl n , by the substitu- 
 tion of a metal or other radicle (which may itself contain chlorine), for an equivalent 
 quantity of hydrogen. Those which are volatile contain, in two volumes of vapour, 
 1, 2, 3, &c. atoms of chlorine, according as the radicle with which the chlorine is as- 
 sociated is mono-, di-, tri-atomic, &c.*, thus : 
 
 2 voL chloride of ethyl, C 2 H 5 .C1, contain 1 at. chlorine 
 sulphuryl, (S0 2 )".C1 2 2 
 
 boron, B.C1 3 3 
 
 silicium, SiCl 4 4 
 
 Chlorides may be conveniently divided into the following groups, each of which 
 contains compounds derived from one or more atoms of hydrochloric acid. 
 
 a. Metallic Chlorides. Chlorine combines with all metals, the number of 
 chlorine-atoms in the resulting molecule varying from 1 to 7. 
 
 a. Chlorides, with one atom of chlorine, formed on the type of the single atom of hy- 
 drochloric acid, HC1, namely, protochlorides, MCI, and hemichlorides, or sub- 
 chlorides, M 2 C1. The greater number of metals form protochlorides, all indeed, 
 except aluminium, antimony, arsenic, bismuth, tantalum, titanium, tungsten, vanadium 
 and zirconium. The protochlorides are all more or less soluble in water, except those 
 of silver and platinum, which are quite insoluble. The protochlorides of gold, platinum, 
 
 * If, however, the radicle contains chlorine, this statement must be understood as applying only to the 
 portion of chlorine which is not thus included, and is removable by water or by aqueous potash ; for 
 example, 2 vols. chloride of trichloracetj 1, C 2 C1 3 O.C1 contain 4 atoms of chlorine; but only one of these 
 is removable by water, the compound, treated with water, yielding hydrochloric acid and trichloracetic 
 acid (C2CPO.C1 + R2Q = HC1 -- C*U 3 O.H.O). 
 
CHLORIDES. 895 
 
 and palladium, are completely decomposed at a red beat ; that of copper, partially. 
 The other protochlorides melt 'when heated, and volatilise unchanged at higher tempe- 
 ratures. Several hydrated protochlorides, those of magnesium and zinc, for instance, 
 are resolved more or less completely by heat into metallic oxide and hydrochloric acid. 
 The fused protochlorides are electrolytic. 
 
 The hemi-atomic metals, especially copper and mercury, form subchlorides, con- 
 taining, e. g. Cu-Cl, Hg 2 Cl. They are insoluble in water, and under certain circumstances 
 manifest a tendency to break up into metal and protochloride. 
 
 0. Chlorides with two atoms of chlorine, formed on the type. H 2 C1 2 , namely, Bi- 
 chlorides, M"C1 2 . The metals which form dichlorides, are molybdenum, palladium, 
 platinum, tellurium, tin, titanium, tungsten, and vanadium. The dichlorides of platinum 
 and palladium give off at a gentle heat one half, and at a stronger heat the whole of 
 their chlorine. The others are easily volatile. 
 
 7. Chlorides with three atoms of chlorine, formed on the type H 3 C1 S , namely, Tri- 
 chlorides, M'"CP, and sesquichlorides, (M 2 )'"C1 3 . The metals which form tri- 
 chlorides are antimony, arsenic, bismuth, gold, molybdenum, tungsten, and vanadium. 
 Trichloride of gold is reduced at a gentle heat to protochloride, which at a higher 
 temperature is resolved into chlorine and metal. The rest volatilise unchanged. The 
 trichlorides of antimony and bismuth are very fusible solids ; the rest are liquids. 
 The volatile trichlorides are decomposed by water, yielding hydrochloric acid and an 
 oxychloride, thus : Bid 3 + H 2 = 2HC1 + BiClO. 
 
 The sesquichlorides are formed from a triple molecule of hydrochloric acid, by the 
 substitution of 2 at. of a sesqui-atomic metal for 3 at. hydrogen ; the metals which 
 form them are aluminium, cerium (?), chromium, iron, and manganese. The cerium 
 and manganese compounds are known only as hydrates ; the rest are fusible and volatile 
 solids. They are all soluble in water, and are-partially decomposed by heat. 
 
 8. Chlorides with four atoms of chlorine, formed on the type H 4 C1 4 , namely, Tetra- 
 chlo rides. These are formed only by the metals tin, titanium, and zirconium. 
 The first two are liquids, the third solid : they are all volatile, and their general be- 
 haviour shows that two of the chlorine-atoms are retained less forcibly than the other 
 two. The tetrachlorides of tin and titanium are soluble in water ; the zirconium- 
 compound is decomposed by water. 
 
 . Chloride with 5 at. chlorine. Pentachloride of antimony, SbCP. Volatile liquid, 
 decomposed by water. 
 
 There are no hcxachlorides known, and only one heptachloride, namely, the hepta- 
 chloride of manganese, Mn 2 Cl 7 . 
 
 Formation of Metallic Chlorides. Chlorides are generally prepared by one or other 
 of the following processes, a. By acting upon the metal with chlorine gas. This 
 method is frequently employed for the preparation of anhydrous chlorides. The penta- 
 chloride of antimony and protochloride of copper are examples of chlorides sometimes 
 produced in this manner. The chlorides of gold and platinum are usually prepared by 
 acting upon the metals with nascent chlorine, developed by the mutual action of 
 hydrochloric and nitric acids. Sometimes, on the other hand, the metal is in a nascent 
 state, as when titanic chloride is formed by passing a current of chlorine over a heated 
 mixture of charcoal and titanic anhydride. The chlorides of aluminium and chromium 
 may be obtained by similar processes. 
 
 j8. Chlorine gas, by its action upon metallic oxides, drives out the oxygen, and 
 unites with the respective metals to form chlorides. This reaction sometimes takes 
 place at ordinary temperatures, as is the case with oxide of silver; sometimes only at 
 a red heat, as is the case with the oxides of the alkali- and alkaline earth-metals. The 
 hydrates and carbonates of these last metals, when dissolved or suspended in hot 
 water and treated with excess of chlorine, are converted, chiefly into chlorides, partly 
 into chlorates. 
 
 y. Many metallic chlorides are prepared by acting upon the metals with hydrochloric 
 acid. Zinc, cadmium, iron, nickel, cobalt, and tin dissolve readily in hydrochloric 
 acid, with liberation of hydrogen ; copper only in the strong boiling acid ; silver, 
 mercury, palladium, platinum, and gold, not at all. Sometimes the metal is substi- 
 tuted, not for hydrogen, but for some other metal. Stannous chloride, for instance, is 
 frequently made by distilling metallic tin with mercuric chloride, thus : 2HgCl + Sn = 
 SnCP + Hg 2 . 
 
 S. Or the oxide, hydrate, or carbonate of metal may be dissolved in hydrochloric 
 acid. In this way the hydrated protochloride of copper and sesquichloride of iron 
 are usually made : 
 
 Cu 2 + 2HC1 = H 2 + 2CuCl. 
 Fe 2 H 3 3 + 3HC1 = 3H 2 + Fe 2 CP. 
 
 With a peroxide, the reaction is accompanied by an evolution of chlorine, thus : 
 Pb 2 2 + 4HC1 = 2H 2 + 2PbCl + Cl 2 . 
 
896 CHLORIDES. 
 
 . Chloride of silver and mercurous chloride, which are insoluble in water, and 
 chloride of lead, which is but sparingly soluble, are easily formed by precipitating any 
 of the corresponding soluble salts with a soluble chloride, thus : 
 NaCl + AgNO 8 = AgCl + NaNO 3 . 
 
 Decompositions. 1. The action of heat upon chlorides has been already noticed. 
 Most protochlorides volatilise at high temperatures, without decomposition ; the higher 
 chlorides give off part of their chlorine when heated. 2. Some chlorides which resist 
 the action of heat alone are decomposed by ignition in the air, yielding metallic oxides 
 and free chlorine : this is the case with the chlorides of iron and manganese ; but most 
 protochlorides remain undecomposed, even in this case. 3. All metallic chlorides, ex- 
 cepting those of the alkali-metals and earth-metals, are decomposed at a red heat by 
 hydrogen gas, with formation of hydrochloric acid : in this way, metallic iron may be 
 obtained in fine cubical crystals. Chloride of silver placed in contact with metallic 
 zinc or iron, under dilute sulphuric or hydrochloric acid, is reduced to the metallic 
 state by the nascent hydrogen. 4. Metallic chlorides, which are not decomposed by 
 heat alone, likewise resist the action of charcoal at a white heat, but if aqueous vapour 
 is likewise present, decomposition takes place, the metal being reduced, and hydro- 
 chloric acid formed, together with an oxide of carbon, e. g. : 
 
 2AgCl + H ? + C = Ag 8 + 2HC1 + CO. 
 
 5. Metallic chlorides are not decomposed by heating with sulphur, but phosphorus 
 decomposes several of them. 6. Those metallic chlorides which are not decomposed 
 by heat alone, likewise resist decomposition when heated to whiteness with boric an- 
 hydride, or silicic anhydride ; but if water is present, hydrochloric acid is evolved, 
 and a borate or silicate of the metal is produced. Vapour of sulphuric anhydride, 
 however, decomposes certain metallic chlorides, a sulphate being formed, and a mixture 
 of equal volumes of chlorine and sulphurous anhydride evolved, e.g.: 
 2NaCl + 2S0 3 = Na 2 S0 4 + SO 2 + CP. 
 
 7. Sulphuric, phosphoric, boric, and arsenic acids, decompose most metallic chlorides, 
 sometimes at ordinary, sometimes at higher temperatures. 8. All metallic chlorides 
 heated with peroxide of lead or manganese and sulphuric acid, give off chlorine, e. g. : 
 2NaCl + Mn 2 2 + 2H 2 S0 4 = Na 2 S0 4 + Mn 2 S0 4 + 2H 2 -t Cl 2 . 
 
 9. Distilled with sulphuric acid and chromate of potassium, they yield a dark 
 bluish-red distillate of chloro-chromic acid. 10. Some metallic chlorides are decom- 
 posed by water, forming hydrochloric acid and an oxychloride, e. g. : Bid 3 + H 2 = 
 2HC1 + BiClO. The chlorides of antimony and stannous chloride are decomposed in 
 a similar manner. 11. All soluble chlorides give with solution of nitrate of silver, a 
 white precipitate of chloride of silver, easily soluble in ammonia, insoluble in nitric 
 acid. With mercurous nitrate, they yield a white curdy precipitate of mercurous 
 chloride, blackened by ammonia ; and with lead-salts, not too dilute, a white crys- 
 talline precipitate of chloride of lead, soluble in excess of water. 
 
 Combinations. Metallic chlorides unite with each other and with the chlorides of 
 the non-metallic elements, forming such compounds as chloromercurate of potassium, 
 KCLHgCl, chloroplatinate of sodium, NaCl.PtCP, chloriodate of potassium, KC1.IC1 3 , 
 &c. They also combine with oxides and sulphides, forming oxychlorides and sulpho- 
 chlorides. Metallic chlorides likewise combine in definite proportions with am- 
 monia and organic bases ; the chlorides of platinum form with ammonia the compounds 
 NH 3 .PtCl, 2NH 3 .PtCl, NH 3 .PtCP, and 2NH 3 .PtCP; mercuric chloride forms with 
 phenylamine the compound C 6 H 7 N.HgCl; with chinoline, C 9 H 7 N.2HgCl, &c. Many 
 of these compounds may be regarded as chlorides of metalloi'dal radicles, formed on 
 the ammonium type : thus, ammonio-protochloride of platinum, NH 3 .PtCl = chloride 
 of platammonium (NH 3 Pt).Cl. 
 
 Many metallic chlorides are soluble in alcohol, ether, volatile oils, &c. 
 
 b. Chlorides of Organo-metallic Radicles (including Phosphorus-bases). 
 These compounds, which bear considerable resemblance to the simple metallic chlo- 
 rides, are produced, either by the direct union of chlorine with the organo-metallic 
 radicle, or by the action of hydrochloric acid on the oxide or hydrate of that radicle. 
 Some of them are volatile liquids ; others crystalline solids. They contain 1, 2, 3, 
 or 4 at. of chlorine associated with 1 molecule of thft organo-metallic radicle, those 
 which contain an even number of atoms of alcohol-radicle forming mono- and tri- 
 chlorides, while those which contain an uneven number of atoms of alcohol-radicle 
 form di- and tetrachlorides, thus : 
 
 Arsen-monomethyl forms AsMeCl 2 and AsMeCl 4 
 
 Arsen-dimethyl AsMe'Cl . AsMe 2 CP 
 
 Stib-triethyl SbMe 3 CP 
 
 Stib-tetramethylium SbMe^Cl 
 
CHLORIDES. 897 
 
 All these compounds may be regarded as derived from a molecule of tri- or penta- 
 chloride of arsenic or antimony by the substitution of an alcohol -radicle for an equiva- 
 lent quantity of chlorine (pp. 339, 397, 411). 
 
 3. Chlorides of Alcohol-Radicles. Hydrochloric or Chlorhydric Ethers. 
 These compounds may be regarded as derived from hydrochloric acid in a similar 
 manner to the metallic chlorides, or from the corresponding alcohols' by the substitution 
 of chlorine for an equivalent quantity of peroxide of hydrogen, e. g. : 
 
 Chloride of ethyl, C 2 H 5 .C1 from Ethylic alcohol, C 2 H 5 .HO 
 Chloride of ethylene, C'H'.Cl 2 Glycol, C 2 H 4 .(HO) 2 
 
 Chloride of glyceryl, C 3 H 5 .C1 3 Glycerin, C 8 H 5 .(HO) 3 
 
 a. The monatomic alcoholic chlorides are obtained : 
 
 1. By the action of hydrochloric acid on the alcohols : 
 
 C 2 H 5 .H.O + HC1 = H 2 + C 2 H 5 .C1. 
 
 2. By the action of the chlorides of phosphorus, or of oxychloride of phosphorus, on 
 the alcohols : 
 
 3(C 2 H 5 .H.O) + PCI 3 = H 3 P0 3 + 3C 2 H 5 C1. 
 3(C 2 H 5 .H.O) + PC1 3 = H 3 P0 4 + 3C 2 H 5 C1. 
 
 3. By the action of chlorine on the corresponding hydrides. This reaction has been 
 observed only in the case of hydride of benzyl (p. 573). 
 
 Most of these monatomic chlorides are liquids more volatile than the corresponding 
 alcohols : one, viz. chloride of methyl, is gaseous at ordinary temperatures, and chloride 
 of cetyl is solid. Treated with alcoholic potash, they yield chloride of potassium and 
 an alcohol : 
 
 C 2 H 5 C1 + KHO = KC1 + C 2 H 5 .H.O 
 
 When recently prepared, they do not precipitate nitrate of silver immediately; but 
 when they are heated with it in sealed tubes, a slow precipitation takes place. Sodium 
 at ordinary temperatures decomposes them, with formation of chloride of sodium and 
 an alcohol-radicle : 
 
 2C 8 H 17 C1 + Na 2 = 2NaCl + C 8 H 17 .C 8 H 17 . 
 
 Chloride of Octyl. 
 
 octyl. 
 
 But if heat be applied, the sodium assumes a violet tint and swells up considerably. 
 The liquid then becomes hot ; hydrogen is evolved ; the violet colour disappears ; and 
 a pasty mass is ultimately obtained, consisting of chloride of sodium and an oil, which 
 is the corresponding hydrocarbon, C^H 2 " : thus, with chloride of octyl : 
 
 2(C 8 H 17 .C1) + Na 2 = 2(C 8 H' 6 Na.Cl) + HH 
 and: C 8 H 17 Na.Cl = NaCl + C 8 H 16 . 
 
 Violet substance. Octylene. 
 
 The same violet substance is produced by the simultaneous action of chlorine and 
 sodium on octylene. It quickly turns white in contact with the air, yielding soda and 
 chloride of sodium, and is quickly decomposed by water, alcohol, and other liquids 
 containing oxygen (B oui s, N. Ann. Chim. Phys. xliv. 114). A similar violet substance 
 is formed by the action of potassium on chloride of phenyl. 
 
 0. The diatomic alcoholic chlorides are produced : 1. By the direct union of chlorine 
 with the corresponding diatomic hydrocarbons, e.g. chloride of ethylene, chloride of 
 tetrylene, &c. 2. By the action of pentachloride of phosphorus on the corresponding 
 alcohols, e. g. : 
 
 C 2 H'.H 2 .0 2 + 2PC1 5 = C 2 H 4 C1 2 + 2POC1 3 + 2HCL 
 
 Glycol. Chloride of 
 
 ethylene. 
 
 Two series of these chlorides are known, containing the radicles C"H 2n , homologous 
 with ethylene, and C n H 5!n - 8 , homologous with benzylene. 
 
 The chlorides C n H 8n Cl 2 , are liquids, for the most part volatile without decomposition. 
 They are decomposed by chlorine, yielding substitution-products. Heated with al- 
 coholic potash, they yield chloride of potassium, and the chloride of an aldehyde- 
 radicle : 
 
 C 2 H<C1 2 + KHO = C 2 H 3 C1 + KC1 + IPO. 
 
 Sulphide of potassium simply converts them into sulphides of diatomic alcohol- 
 radicles : 
 
 C 2 H 4 C1 2 + K 2 S = 2KC1 + C 2 H 4 S. 
 
 Heated with ammonia in sealed tubes, they appear to yield the same products as the 
 corresponding bromides, viz. diamines containing 1, 2, or 3 at. of the radicles C"H 2n ; 
 but the reactions have not been so much examined as those of the bromides. (See 
 AMMONIUM-BASES, p. 196 ; also ETHYI/ENE-BASKS.) 
 
 VOL. I. 3 M 
 
898 CHLORIDES. 
 
 The chlorides C"H 2n - 8 Cl 2 , are also volatile liquids heavier than water. Heated with 
 alcoholic potash, they yield chloride of potassium and an aldehyde : e. g. chloride of 
 benzylene yields bitter-almond oil. (Wicke, Ann. Ch. Pharm. cii. 356) : 
 C 7 H 6 C1 8 + KHO = KC1 + HC1 + C 7 H 6 0. 
 
 Ammonia heated with chloride of benzylene in sealed tubes, acts in like manner 
 ("Wicke). With alcoholic sulphide of potassium, they are decomposed like the chlo- 
 rides last mentioned, yielding diatomic sulphides. 
 
 7. Of triatomic alcoholic chlorides, only one is known, viz. chloride of glyceryl or 
 trichlorhydrin, (C 3 H S )'"CP, which is produced by the action of peutachloride of phos- 
 
 TTO 
 
 phorus on dichlorhydrin, (C'H 5 )'" . (See CKLORHYDBINS, p. 894.) 
 
 4. Chlorides of Aldehyde-Radicles. These are monatomic chlorides of the 
 general form OH* 1 - 1 Cl, isomeric with the monochlorinated diatomic alcohol-radicles, 
 e. g. chloride of vinyl, C 2 H 3 .C1, with chlorethylene, C 2 (H 3 C1). They are obtained by the 
 action of alcoholic potash on the chlorides of the diatomic alcohol-radicles (p. 987), some- 
 times also by that of oxychloride of carbon on the aldehydes, e. g, C 2 H 3 C1 from acetic 
 aldehyde, C 2 H 4 (Harnitzky, p. 107). It is probable also that they might be ob- 
 tained by treating the aldehydes with pentachloride of phosphorus ; as butyral, the 
 isomer of butylic aldehyde, yields when thus treated, the compound C 8 H 7 C1 (p. 689). 
 
 These chlorides are volatile liquids, except chloride of vinyl, which is gaseous at 
 ordinary temperatures. Chlorine converts them into dichlorides of chlorinated alcohol- 
 radicles. 
 
 5. Chlorides of Acid Radicles. These compounds may be derived from acids 
 by the substitution of chlorine for peroxide of hydrogen, e. g. : 
 
 Chloride of acetyl, C 2 H 3 O.C1 from Acetic acid, C 2 H 3 O.HO 
 
 Chloride of sulphuryl, (S0 2 )".C1 2 Sulphuric acid, (SO-)"(HO) 2 
 Chloride of phosphoryl, (PO)'".CP Phosphoric acid, (PO)'".(HO) 3 
 
 a. Monatomic acid chlorides are mostly derived from organic acids ; in fact, the 
 only inorganic compounds of this class are hydrochloric acid, HC1 ; chloride of azotyl, 
 NO.C1, produced by the direct combination of chlorine and nitric oxide gases, or by 
 the decomposition of nitromuriatic acid ; and chloride of nitryl, N0 2 .C1, produced by 
 the action of oxychloride of phosphorus on nitrate of lead: 3PbN0 3 + PCPO = Pb'PO* 
 + 3N0 2 C1, or by the action of chlorhydrosulphuric acid upon nitre: KNO 3 + HC1SO' 
 = NO V C1 + KHSO 4 . Free chlorine, C1C1, may be regarded as the chloride corre- 
 sponding to hypochlorous acid, Cl.HO. 
 
 The chlorides of monatomic organic acids are obtained : by the action of the chlo- 
 rides of phosphorus, or of the oxychloride, on the corresponding acids : 
 C 7 H 5 O.H.O + PCP.C1 2 = C'H 5 O.C1 + HC1 + PCP.O. 
 
 Benzole acid. Chloride of 
 
 benzoyl. 
 
 or of trichloride or oxychloride of phosphorus on salts of the same acids : 
 3(C 7 H 5 O.K.O) + PCPO = K 8 PO* + 3(C 7 H 5 O.C1). 
 
 Benzoate of Chloride of 
 
 potassium. benzoyl. 
 
 sometimes also by the action of chlorine on the corresponding hydrides (aldehydes) : 
 
 C 7 H 5 O.H + Cl 2 == C 7 H 5 O.C1 + HC1. 
 
 They are mostly fuming volatile liquids (chloride of cyanogen, CN.C1, is gaseous), 
 remarkable for the facility with which they are decomposed by water and its deriva- 
 tives (alcohols, alkalis, alkaline salts, &c.), and by ammonia and the compound 
 ammonias. 
 
 Water transforms them into hydrochloric acid and a monobasic organic acid : 
 C 2 H 3 O.C1 + H 2 = HC1 + C 2 H 3 O.H.O. 
 
 Chloride of Acetic acid. 
 
 acetyl. 
 
 "With alkalis, in like manner, they yield the alkaline salts of the corresponding acids, 
 and with acids, compound ethers : 
 
 C 2 H 3 O.C1 + C 2 H 5 .H,0 HC1 + C 2 H 3 O.C 2 H 5 .0. 
 
 Chloride of Alcohol. Acetate of ethyl. 
 
 acetyl. 
 
 Distilled with the alkaline salts of monobasic acids, they yield anhydrides : 
 C 2 H S O.C1 + C 2 H 8 O.KO = KC1 + (C 2 H 3 0) 2 0. 
 
 Chloride of Acetate of Acetic 
 
 acetyl. potassium. anhydride. 
 
 C 2 H 3 O.C1 + C 7 H 5 O.K.O = KC1 + C 2 H S O.C 7 H I( 0.0. 
 
 Chloride of Benzoate of Aceto-benzoic 
 
 acetyl. potassium. anhydride. 
 
CHLORIDES. 899 
 
 With ammonia, or carbonate of ammonium, they yield primary amides : 
 C 7 H 5 O.C1 + NH S = HC1 + KH 2 .C 7 H 5 0. 
 
 Chloride of Benz amide. 
 
 benzoyl. 
 
 and with compound ammonias they yield alkalamides : 
 
 C 7 H 5 O.C1 + N.H 2 .C 6 H 5 = HC1 + N.H.C 6 H 5 .C 7 H 5 0. 
 
 Chloride of Pheny- Phenyl-benzamide. 
 
 benzoyl. lamine. 
 
 In like manner, with primary amides they form secondary amides : 
 
 C 7 H 5 O.C1 + N.H 2 .C V H 3 = HC1 + N.H.C 2 H 3 O.C 7 H 5 0. 
 
 Chloride of Acetamide. Aceto-benzamide. 
 
 benzoyl. 
 
 /3. Diatomic acid chlorides, derived from a double molecule of hydrochloric acid, and 
 corresponding to dibasic acids. Such are : 
 
 Chloride of carbonyl (phosgene) (CO)".C1 2 
 
 Chloride of sulphuryl . . . . . . . (SO 2 )".CP 
 
 Chloride of succinyl (C 4 H 4 2 )".C1 2 
 
 Two volumes of the vapour of these chlorides contain 2 atoms of chlorine capable of 
 conversion into a metallic chloride by the action of a mineral alkali. 
 
 They are obtained by the action of pentachloride of phosphorus on dibasic acids or 
 anhydrides, the reaction, as shown by Williamson, consisting of two stages, the first 
 resulting in the formation of a chlorinated acid, the second in that of a chloride, e. g. 
 with sulphuric acid : 
 
 + PCP.CP = (SO 2 )" JQJ + HC1 + POC1 3 . 
 
 Chlor-hydrp- 
 sulphuric acid. 
 
 ( S 2 )"JC1 + PCP.CP = (S0 2 )".CP + HC1 + POCP. 
 
 Chloride of 
 sulphuryl. 
 
 Chloride of sulphuryl and chloride of carbonyl are also formed by the direct combi- 
 nation of chlorine with the radicles, under the influence of light. 
 
 The diatomic acid chlorides are liquid at ordinary temperatures, with the exception 
 of phosgene, which is gaseous. Their reactions are similar to those of the monatomio 
 chlorides. 
 
 7. Triatomic Acid Chlorides, corresponding to tribasic acids, and containing in 
 two volumes of vapour, 3 vol. chlorine capable of conversion into a metallic chloride 
 by the action of an alkali. Such are : 
 
 Trichloride of phosphorus PCI 3 
 
 Chloride of phosphoryl (oxychloride of phosphorus) . . PO.CP . 
 
 Chloride of sulphophosphoryl PS.CP 
 
 Chloride of boron B.C1 3 
 
 Chloride of cyanogen (solid) (CN) 3 .CP 
 
 The trichlorides of arsenic and antimony must also be regarded as acid chlorides. The 
 explosive compound, commonly called chloride of nitrogen, is perhaps also a trichlo- 
 ride, NCI 3 ; but, according to some authorities, it contains hydrogen. 
 
 Acid trichlorides are produced, for the most part, by the direct action of chlorine on 
 the radicles. Chloride of phosphoryl is produced by the action of water, and of various 
 derivatives of water, on the pentachloride, PCP + H 2 = 2HC1 + POCP; and chloride 
 of sulphophosphoryl, in like manner by the action of sulphydric acid on the penta- 
 chloride. All these compounds are decomposed by water and its derivatives in the 
 same manner as the mono- and di-atomic chlorides, yielding acids, salts, and compound 
 ethers. Most of them unite with monatomic metallic chlorides, forming double chlorides. 
 
 8. Tetratomic Acid Chlorides, containing 4 at. chlorine in 2 vols. of vapour. Some 
 of the tetratomic metallic chlorides are of acid character, viz. SnCl 4 and TiCl 4 ; chloride 
 of silicium, SiCl 4 , is also tetratomic. The only organic compound of this class is tetra- 
 chloride of carbon, CC1 4 (p. 765). In these chlorides, two of the chlorine-atoms are re- 
 tained less forcibly than the other two. 
 
 t. Pentatomic Acid Chlorides. Two only of these compounds are known, viz. PCI* 
 and SbCP. They are both volatile, but the antimonic chloride suffers partial decom- 
 position at the same time. To each of these chlorides there is a corresponding tri- 
 chloride, and their general relations indicate that two of the chlorine-atoms are 
 retained less forcibly than the other three. 
 
 With 1 at. of water, they yield hydrochloric acid and an oxychloride, e. g. : 
 PCP + H 2 = 2HC1 + PCPO, 
 3 M 2 
 
900 CHLORINDATMITE CHLORINE. 
 
 but an excess of water likewise decomposes the oxychloride, forming hydrochloric acid 
 and phosphoric or antimonic acid. Similar reactions are produced by alkalis, and in the 
 case of pentachloride of phosphorus, by alcohols, the products being hydrochloric acid, 
 a chloride of the alcohol-radicle, and either oxychloride of phosphorus or a phosphate 
 of the radicle, according to the quantities present. Thus with phenylic alcohol : 
 
 PCI 5 + C 6 H 5 .H.O = C 6 H 5 .C1 + HC1 + PC1 S 0, 
 and PC1 3 + 3(C 6 H 5 .H.O) = (C 6 H 5 ) 3 P0 4 + 3HC1. 
 
 With acids, or with salts of alkali-metal (acetate of sodium, for example) penta- 
 chloride of phosphorus yields oxychloride of phosphorus, hydrochloric acid, and a 
 chloride of the acid radicle (pp. 898, 899), and in some cases, if a salt of the alkali- 
 metal is present in excess, the corresponding anhydride is formed : thus 
 C 7 H 5 O.Na.O + PCI 5 = PCP.O + NaCl + C 7 H 5 O.C1; 
 
 Benzoate of Chloride of 
 
 sodium. benzoyl. 
 
 and C 7 H 8 O.Na.O + C 7 H 5 O.C1 = NaCl + (C 7 H 5 0) 8 0. 
 
 Benzoate of Chloride of Benzoic 
 
 sodium. benzoyl anhydride. 
 
 CHXiORXOTD A.TMITE. A product of the action of chlorine upon indigo (q. v.) 
 
 CHX.ORIRTDXHr. See INDIN. 
 
 CHLORINE. Symbol Cl. Atomic weight 35'5. Density 35'5 (referred to hydrogen 
 as unity.) Atomic volume 1. 
 
 Chlorine is a substance very widely distributed in nature. It exists chiefly in the 
 form of chloride of sodium, which constitutes rock-salt when deposited in inland beds, 
 sea-salt when dissolved in masses of water. The sea also contains chlorides of potas- 
 sium, calcium, and magnesium. The chlorides of calcium, lead, mercury, and silver, 
 respectively, form the partial or sole constituents of several well-known minerals, and 
 free hydrochloric acid has been met with in the air of volcanic neighbourhoods. 
 Chlorine was discovered by Scheele in 1774. Its elementary nature was first esta- 
 blished by Davy in 1810. 
 
 1. Chlorine is usually prepared by the action of hydrochloric acid upon peroxide of 
 manganese, at a gentle heat : 
 
 4HC1 + Mn 2 2 = 2H 2 + 2MnCl + Cl 2 . 
 
 The liberated chlorine may be washed by transmission through a small quantity of 
 water, and dried with oil of vitrol in the usual manner. It is best collected by down- 
 ward displacement. It cannot be collected over mercury, on account of its rapid 
 action on the metal. It cannot readily be collected over water, on account of solubility 
 therein ; but the difficulty may be obviated by evolving the gas rapidly, or by passing 
 the delivery tube to the summit of the receiver, or by keeping the water in the trough 
 perceptibly warm, or by saturating it with common salt. In the above reaction, the 
 peroxide of manganese may be replaced by acid chromate of potassium ; as also, though 
 with questionable advantage, by several other oxidising agents, such as red or brown 
 oxide of lead, chlorate of potassium, hypochlorite of calcium, nitric acid, &c. More- 
 over, a mixture of common salt and oil of vitrol, which generates hydrochloric acid 
 abundantly, may be, and frequently is, substituted for the ready formed hydrochloric 
 acid, thus : 
 
 2NaCl + 2H 2 S0 4 + Mn 2 2 = Na 2 S0 4 + Mn 2 S0 4 -I- 2H 2 + Cl 2 . 
 This is the method usually adopted on the large scale, to generate chlorine for the 
 manufacture of bleaching powder, chlorate of potassium, &c. It has the advantage of 
 eliminating the whole of the chlorine from the chlorine-compound used, whereas, in 
 the decomposition of the peroxide by hydrochloric acid alone, half the chlorine remains 
 as protochloride of manganese. The sulphuric acid, when present in excess, has also 
 the effect of drying the chlorine. The materials are mixed in a large alembic of nearly 
 spherical form, and constructed either entirely of lead, surrounded at its lower part 
 with a cast-iron steam-jacket, or of two hemispheres joined together in the middle, 
 the \ipper being of lead, the lower of iron. In the former case the vessel is heated 
 by steam, in the latter over a very gentle open fire. (See Ure's Dictionary of Arts, 
 Manufactures and Mines, i. 666.) 
 
 Another method, which may be economically practised in sulphuric acid works, con- 
 sists in heating a mixture of common salt and nitrate of sodium (Chili saltpetre) with 
 excess of sulphuric acid. Hydrochloric and nitric acids are thereby evolved, and by 
 their mutual action generate chlorine, peroxide of nitrogen and water : 
 
 HC1 + HNO 3 = Cl + NO 2 + H 2 0. 
 
 The mixed vapours are made to pass into condensers containing sulphuric acid, 
 which absorbs the peroxide of nitrogen, forming a peculiar compound, which is after- 
 wards used in the manufacture of sulphuric acid itself (see SULPHURIC ACID), while the 
 
CHLORINE. 901 
 
 chlorine passes on and may be used for the preparation of chlorates or hypochlorites. 
 The residue of acid sulphate of sodium, left by the action of the sulphuric acid on the 
 mixture of nitre and salt, remains liquid, and may be run off into a furnace and heated 
 with an additional quantity of salt, producing hydrochloric acid and neutral sulphate of 
 sodium, which last may be used in the manufacture of soda. (Traitb de Chimie gene-' 
 rale, par Pelouze et Fremy, 3 me ed. i. 414.) 
 
 2. Chlorine is also liberated by the simple action of a red heat upon certain chlorides, 
 such as those of palladium, platinum, and gold, thus : PtCl 2 = Pt + CP. Pentachloride 
 of antimony, SbCP, breaks up, when gently heated, into trichloride of antimony, SbCl 3 , 
 and free chlorine, Cl 2 ; and in like manner, the trichloride of gold, AuCl 3 , breaks up 
 into protochloride of gold, AuCl, and free chlorine, Cl 2 . Moreover, chlorine gas fre- 
 quently results from the decomposition of its oxidised compounds. 
 
 Properties. Chlorine has a yellowish-green colour, whence its name (xA.wpos), and 
 a pungent irritating smell. It is irrespirable unless very much diluted. It is one of 
 the heaviest substances that are gaseous at common temperatures, being 35J times 
 heavier than hydrogen, and 2^ times heavier than atmospheric air. By a pressure of 
 four atmospheres, at mean temperature 15'5 C., it is condensed into a yellow mobile 
 liquid, having a specific gravity T33. It has resisted all attempts at solidification. At 
 ordinary temperatures, water dissolves about twice its volume of chlorine, forming a 
 solution which has the colour, smell, and general chemical properties of the gas. At low 
 temperatures, water dissolves a still greater proportion of chlorine, and at the tempera- 
 ture C. a definite hydrate of chlorine, C1.5.H-0, crystallises out. If this hydrate be 
 gently warmed in a sealed tube, it will, at a temperature of 38 C., decompose into a 
 layer of water floating over a layer of Liquid chlorine. This liquid chlorine may be 
 readily distilled off, and condensed by means of a freezing mixture at the other extremity 
 of the tube, which is usually bent for this purpose at an obtuse angle. 
 
 Chlorine possesses very active chemical properties, and gives origin to many phe- 
 nomena of combination, substitution and indirect oxidation. It is moreover, non- 
 inflammable, and does not unite directly with oxygen under any circumstances. At 
 ordinary temperatures, chlorine combines directly with all the metals, with many me- 
 talloids, such as hydrogen and phosphorus, and with many compound bodies, such as 
 sulphurous anhydride, SO 2 , olefiant gas, C 2 H 4 , benzene, C 6 H 6 , and carbonic oxide, CO. 
 Its union with phosphorus, and with finely divided arsenic, antimony, tin, or copper, 
 is attended with the phenomena of combustion. At increased temperatures, chlorine 
 combines with many other substances, such as sulphur, selenium, boron, and silicon. 
 It has not been made to combine directly with carbon. When ordinary combustible 
 bodies containing carbon and hydrogen, such as paper, wood, wax-taper, &c., are 
 ignited and immersed in a vessel of chlorine, the combustion continues chiefly at the 
 expense of the hydrogen, which forms hydrochloric acid, while the carbon is deposited 
 as a dense black smoke. Previous ignition of the hydrocarbonised substance is not 
 always necessary to induce these phenomena. Paper dipped in oil of turpentine, 
 C 10 !! 10 , and plunged in a vessel of the gas, takes fire spontaneously, yielding abundance 
 of hydrochloric acid and carbon. 
 
 Chlorine displaces bromine, iodine, an&faiorine, from their combinations, by equiva- 
 lent substitution. Free iodine strikes a deep blue colour with starch ; and when 
 starched paper dipped in iodide of potassium solution is brought into contact with 
 chlorine, the iodine is liberated by the chlorine, and the characteristic blue iodide of 
 starch produced : KI + Cl = KC1 + I. Chlorine also displaces hydrogen by equivalent 
 substitution, one half of the chlorine taking the place of an equivalent quantity of 
 hydrogen, while the other half unites with the hydrogen eliminated : 
 C i3 H ,80T + C p = C"H> 7 C10 7 + HC1. 
 
 Salicin. Chloro salicin. 
 
 C 2 H 4 2 + Cl 6 = C'HCPO 2 + 3HC1. 
 Acetic acid. Trichloracetic 
 
 acid. 
 
 Chlorine, by combining with hydrogen or a metal, acts indirectly as an oxidising 
 agent. Thus, when chlorine-water is exposed to the action of sunlight, we have 
 Cl 2 + H 2 O = 2HC1 + 0. Again, when ferric hydrate, suspended in solution of hydrate 
 of potassium, is treated with chlorine, we have produced ferric and hydrochloric acids, 
 which react with the alkali to form potassium salts : 
 
 H?0 + Fe 2 H 8 3 + CP = IFO.Fe 2 3 , (i.e. H 2 Fe 2 4 ) + 3HCL 
 
 Ferric Ferric, 
 
 hydrate. acid. 
 
 Chlorine destroys the colour of most organic pigments. This bleaching action is 
 usually accompanied by oxidation and substitution, thus : 
 
 C 9 H 5 NO + H 2 -r Cl 4 = C 8 H 4 CLN0 2 + 3HC1. 
 Indigo. Chlorisatin. 
 
 SM 3 
 
902 CHLORINE. 
 
 Chlorine also destroys odours of various kinds, and possibly infectious miasmata, 
 either by abstracting hydrogen with or without substitution, or by indirectly oxidis- 
 ing. W. O. 
 
 Antichloristic Theory. Chlorine was originally regarded as a compound body, 
 namely, Oxygenised muriatic acid, or Oxymuriatic acid. Muriatic acid was supposed 
 to be a compound of oxygen with the unknown radicle Muriaticum, or Murium, and 
 chlorine or oxygenised muriatic acid was supposed to contain the same radicle united 
 with a larger quantity of oxygen. Moreover, as the driest muriatic acid, when brought 
 in contact with red-hot metals, evolves a large quantity of hydrogen, and as 1 vol. 
 of dry chlorine with 1 vol. of dry hydrogen forms 2 vols. of perfectly dry muriatic 
 acid gas, it was concluded that 1 vol. of chlorine (or oxymuriatic acid), contains a 
 half volume of oxygen, which, in the formation of muriatic acid gas, combines with 
 1 vol. of hydrogen ; and that muriatic acid gas is an intimate compound, in equal 
 numbers of atoms, of water, and a not yet isolated anhydrous muriatic acid, which 
 may be called hypothetical anhydrous muriatic acid, to distinguish it from ordinary dry 
 muriatic acid gas. Berzelius formerly arranged the various degrees of oxidation in the 
 series as follows : 
 
 1 at. Murium =1 1 '4 . fnrms 
 
 takes up of oxygen therewith Antichloristic Names. Chloristic Names. 
 
 2 at. = 16 ... 27'4 pts. of Hyp. anhyd. muriatic acid. 
 
 3 = 24 ... 35*4 Oxymuriatic acid. Chlorine. 
 
 4 = 32 ... 43-4 Euchlorine. Hypochlorous an- 
 
 hydride. 
 
 6 = 48 ... 59-4 ? Perchloric oxide. 
 
 8 = 64 ... 75*4 Hyperoxymuriatic acid. Chloric anhydride 
 
 (hyp.) 
 
 10 = 80 ... 91'4 ? Perchloric anhy- 
 
 dride (hyp.) 
 
 It is easy to see that most of the phenomena exhibited by chlorine-compounds, may 
 be rationally expressed in the language of this so-called " antichloristic theory." 
 Muriatic acid gas is supposed to be a compound of 1 at. hypothetical anhydrous 
 muriatic acid = 27'4 with 1 at. water = 9, making together 36'4 (Mu0 2 .HO).* Metallic 
 chlorides are hypothetical anhydrous muriates of metallic oxides, Mu0 2 .KO, and may 
 be formed, with evolution of hydrogen, by contact of a metal with muriatic acid gas, the 
 oxidation of the metal being produced by the water. The same compounds are formed 
 when a metal is immersed in oxymuriatic acid gas (MuO 3 ), the metal then taking 
 away the third atom of oxygen of that gas, and forming an oxide, which unites with 
 the remaining hypothetical anhydrous muriatic acid. The formation of a muriate and 
 hyperoxymuriate (chlorate), when oxymuriatic acid comes in contact with the aqueous 
 solution of an alkali, is effected by 5 at. of oxymuriatic acid giving up their third 
 atom of oxygen to a sixth atom of the same acid, which is thereby converted into 
 hyperoxymuriatic acid [6MuO 3 + 6KO = KO.MuO 8 + 5(KO.Mu0 2 )]. And in all 
 cases in which chlorine is as an oxidising agent, where the one theory supposes that 
 the element chlorine unites with hydrogen as a metal, and sets oxygen free, the other 
 supposes that the third atom of oxygen in MuO 3 , performs the same functions. 
 
 )n the same theory, phosgene gas (oxychloride of carbon), is supposed to be a com- 
 pound of hypothetical anhydrous muriatic acid with carbonic acid (Mu0 2 .C0 2 ) ; terchlo- 
 ride of phosphorus is a muriate of phosphorous acid, P0 3 .3Mu0 2 , and the pentachloride 
 is P0 5 .5Mu0 2 , both compounds being formed by the combustion of phosphorus in the 
 third atom of oxygen of MuO 3 , whereby phosphorous or phosphoric acid is produced, 
 which unites with the resulting MuO 2 . 
 
 Such was the theory of the chlorine-compounds which maintained its ground till 
 1809. In that year, however, Gray-Lussac and Th&nard showed, by arguments founded 
 on numerous experiments, that the chemical relations of the so-called oxymuriatic 
 acid, or chlorine, might all be explained on the supposition that it is an elementary 
 substance, and this view was further carried out by Sir H. Davy in 1810, who first 
 gave to this substance the name of CHLORINE. It is not necessary to go into all the 
 arguments by which this view was ultimately established ; it is sufficient to observe, 
 that chlorine has never been shown to contain oxygen, or indeed to be capable in any 
 way of resolution into simpler forms of matter, and therefore that its claim to the title 
 of an element rests on the same foundation as that of the' other bodies at present re- 
 garded as elementary. (For further details, see Gmelin's Handbook, ii. 356, and Ure's 
 Dictionary of Chemistry, 4th edition, p. 318.) 
 
 * = 8. 
 
CHLORINE: DETECTION. 903 
 
 CHLORINE, DETECTION AN1> ESTIMATION OP. 1. Reactions* 
 Chlorine in the free state is recognised by its suffocating odour, its yellow-green colour, 
 the bleaching action which it exerts on litmus, indigo, and other vegetable colours, and 
 the deep blue colour which it produces with a mixture of starch and iodide of potassium. 
 The aqueous solution exhibits the same characters. 
 
 Hydrochloric acid and solutions of metallic chlorides, either neutral or slightly 
 acidulated with nitric acid, give with nitrate of silver, an immediate white curdy pre- 
 cipitate of chloride of silver, insoluble in hot nitric acid, easily soluble in ammonia ; 
 and with mercurous nitrate, a white curdy precipitate of mercurous chloride (calomel) 
 insoluble in nitric acid and in ammonia, and turned black by ammonia. Both these 
 reactions are extremely delicate. Solutions of chloride of sodium of various degrees 
 of dilution, give with nitrate of silver and mercurous nitrate, the reactions indicated 
 in the following table : 
 
 1 pt. chlorine in : Nitrate of Silver. Mercurous Nitrate. 
 
 100,000 pts. water Slight turbidity. Slight precipitate. 
 
 200,000 Immediate slight cloud. Turbidity after a few 
 
 minutes. 
 400,000 Very slight turbidity. Very slight turbidity 
 
 after some minutes. 
 800,000 Very faint opalescence. Opalescence after some 
 
 time. 
 
 1,600,000 Scarcely perceptible Scarcely perceptible opa- 
 
 opalescence. lescence after some 
 
 time. 
 
 "With solution of sal-ammoniac, the silver-solution behaves in a similar manner, and 
 gives a perceptible cloud, even with 3,200,000 pts. of water; with the mercurous solu- 
 tion, the reaction ceases to be perceptible with 400,000 pts. of water to 1 pt. of chlorine. 
 (Lassaigne, J. Chim. med. viii. 518.) 
 
 The only salts which give with silver-solution a precipitate resembling the chloride, 
 are bromides, iodides, and cyanides. Either of these salts is easily detected in 
 presence of a chloride, viz. bromides and iodides by the colours of the bromine and 
 iodine when set free, and by their reaction with starch-paste ; cyanides by the 
 formation of Prussian blue with ferroso-ferric salts ; but the detection of small quan- 
 tities of chlorine in presence of excess of either of the other salts, presents greater 
 difficulty. Bromide, iodide, and cyanide of silver are all insoluble in cold nitric acid, 
 and more or less soluble in ammonia. Iodine is, however, completely precipitated by 
 nitrate of palladium, which does not precipitate chlorine : consequently the chlorine 
 may be detected by adding nitrate of silver to the filtrate. The best mode of detect- 
 ing a small quantity of a chloride in presence of excess of bromide, is to distil the 
 dried salts with sulphuric acid and acid chromate of potassium, and pass the evolved 
 red vapours into ammonia : if chlorine is present, chlorochromic acid will be evolved, 
 and the liquid will be coloured yellow, from formation of chromate of ammonium ; but 
 if only bromine is present, it will remain colourless. Cyanide of silver dissolves 
 with decomposition when boiled with strong nitric acid, and may thereby be separated 
 from the chloride, which will remain undissolved. 
 
 As the greater number of metallic chlorides are soluble in water, the method of pre- 
 cipitation by nitrate of silver may be applied to them immediately. Cuprous chlo- 
 ride, and many oxychlorides which are insoluble in water, dissolve in nitric acid, 
 and the chlorine contained in them may then be detected in the same manner. Oxy- 
 gen-salts of chlorine, viz. the hypochlorites, chlorites, chlorates, and perchlo- 
 rates, give off their oxygen when heated, and are reduced to chlorides : the reduction, 
 excepting in the case of perchlorates, may also be effected by sulphurous acid. The 
 chlorides of phosphorus and other non-metallic elements, are decomposed by 
 water, yielding hydrochloric acid, in which the chlorine may then be detected by nitrate 
 of silver. The chlorine in organic compounds is for the most part not imme- 
 diately precipitated by nitrate of silver, only indeed when it may be said to exist as 
 hydrochloric acid, namely, in combination with organic bases; from other organic 
 compounds, as the chlorides of the alcohol- radicles, and the numerous class of com- 
 pounds in which chlorine takes the place of hydrogen, it must first be separated, 
 either by ignition with lime, or by heating the compound with nitric acid in a sealed 
 tube (pp. 225, 247). 
 
 2. Quantitative Estimation. Chlorine is always estimated as chloride of 
 silver. If not present as hydrochloric acid or a metallic chloride, it must be reduced 
 to that state by one of the methods just indicated. The solution is then slightly 
 acidulated with nitric acid in the cold (the application of heat to the acid solution 
 would drive -off part of the chlorine) ; nitrate of silver is added in excess ; and the 
 
 3 M 4 
 
904 CHLORINE : ESTIMATION OF. 
 
 liquid either briskly agitated with the precipitate, or else left for some hours in a 
 warm place, till the precipitate has completely settled down. The precipitate is col- 
 lected on a filter, which should be as small as possible, washed with water, and dried 
 at 100C. It must then be separated as completely as possible from the filter, and 
 introduced into a porcelain crucible previously weighed, the filter burnt to ashes out- 
 side the crucible, the ashes added to the contents of the crucible, and the whole strongly 
 heated over a lamp till the chloride of silver is brought to a state of tranquil fusion, 
 after which it is left to cool and weighed. It contains 2474 per cent, chlorine. As a 
 small portion of the chloride may be reduced by the organic matter of the filter during 
 ignition, it is best, before weighing, to treat the cooled mass with a small quantity of 
 nitric acid, in order to dissolve the reduced silver, then add hydrochloric acid, eva- 
 porate to dryness, fuse, and weigh. The quantity of chlorine introduced in this man- 
 ner, will only be the equivalent of that which may have been lost by the previous 
 reduction. The chloride of silver may also be collected on a weighed filter, and dried 
 in an oil-bath at about 150 C. 
 
 The quantity of chlorine in a soluble chloride may also be estimated volume tri- 
 cally, by precipitation with a standard silver-solution, a cubic centimetre of which con- 
 tains 30-42 milligrammes of silver, corresponding to 10 milligrammes of chlorine. 
 
 Volumetric Estimation of Chlorine in Hypochlorites : CHLORIMETRY. The value of 
 the so-called " chlorides of lime, potash, and soda," which are mixtures of the hypo- 
 chlorites, chlorides, and hydrates of the respective metals, depends upon the percentage 
 of hypochlorite which they contain, or, what comes to the same thing, on the quantity 
 of chlorine which they evolve when treated with an acid, thus : 
 2CaC10 + H 2 S0 4 = Ca'SO 4 + H 2 + Cl 2 
 
 and this quantity may be conveniently estimated : a. By the quantity of arsenious 
 anhydride which it will convert into arsenic anhydride in an acid solution : As 2 3 + 
 Cl 4 + 2H 2 = As 2 5 + 4HC1. b. By the quantity of ferrous oxide which it will 
 convert into ferric oxide. c. By the quantity of iodine which it will liberate from a 
 standard solution of iodide of potassium. 
 
 a. 14 grammes of pure arsenious anhydride, dried at 100 C., are dissolved in 
 caustic potash, and the solution is diluted to 1 litre ; 1 cub. cent, of this solution con- 
 tains 0'014 grm. As 2 3 , and requires for its conversion into arsenic anhydride, 
 0-010 grm. chlorine (As 2 3 = 198 : Cl 4 = 142 : : 14 : 10). 
 
 Five grms. chloride of lime are triturated with water, the whole washed into a gra- 
 duated cylinder and diluted to 100 c.c. ; 50 c.c. of the arsenious solution are placed 
 in a beaker, diluted with water, saturated with hydrochloric acid, and coloured blue 
 by a drop of indigo-solution ; and the solution of chloride of lime (well shaken up), is 
 added from a burette, till the blue colour is nearly destroyed. A fresh drop of indigo 
 is now to be added, and then the chlorine-solution again, very cautiously, and drop by 
 drop, the contents of the beaker being continually agitated, till the colour finally dis- 
 appears. This marks the end of the operation : for the decoloration of the indigo does 
 not take place till all the arsenious anhydride is converted into arsenic anhydride. 
 The percentage of available chlorine in the sample is then easily calculated. Suppose 
 that 45 c.c. of the arsenious solution have been employed ; these correspond to 0'45 grm. 
 chlorine : consequently, the sample contains 9 per cent, of chlorine in the form of 
 hypochlorite. 
 
 Another mode of proceeding is to act on a known volume of a standard alkaline 
 solution of arsenious anhydride added in excess, and to estimate the excess by a 
 standard solution of iodine (p. 266). This, according to Mohr, is the only accurate 
 method. 
 
 b. A weighed quantity of the sample is made to act on a known quantity of ferrous 
 sulphate added in excess, and the quantity of that salt unoxidised by the hypochlorite, 
 is estimated by a standard solution of permanganate of potassium. Every 1 at. ferrous 
 oxide converted into ferric oxide, corresponds to 1 at. chlorine : 
 
 2Fe 2 + Cl 2 + H 2 = Fe'O 3 + 2HCL 
 
 c. For the iodometric method, see ANALYSIS, VOLUMETRIC (p. 266. On CHLORIMETRY, 
 see also Ure's Dictionary of Arts, Manufactures and Mines, i. 671). 
 
 3. Separation of Chlorine from other Elements. The method of precipi- 
 tation by nitrate of silver serves to separate chlorine from all other elements except 
 bromine and iodine. 
 
 To estimate chlorine in presence of bromine, the two elements are precipitated to- 
 gether by nitrate of silver, the precipitate dried, ignited, and weighed in the manner 
 just described (p. 904), and the bromine determined by the method given at page 678. 
 From this the quantity of bromide of silver in the precipitate is found by the propor- 
 tion Br : AgBr = 80 : 188; this deducted from the total weight of the precipitate, 
 
CHLORINE : ESTIMATION OF. 905 
 
 gives the quantity of chloride of silver therein; and 2474 per cent, of this last quantity 
 is the amount of chlorine sought. 
 
 The method of estimating chlorine in presence of iodine is precisely similar. 
 
 When chlorine, bromine, and iodine occur together, the iodine is first precipitated 
 by nitrate of palladium (see IODINE), and in the filtrate the chlorine and bromine are 
 determined as above. Or the three elements may be separated and estimated by 
 Field's method (p. 678). 
 
 4. Atomic Weight of Chlorine. The atomic weight of chlorine was determined 
 by Berzelius (Ann. Ch. Phys. [2] xci. 102) in connection with those of silver and 
 potassium ; and the same method has been carried out, with very nearly accordant 
 results, by Marignac (J. pr. Chem. xxxi. 272 ; Ann. Ch. Pharm. xliv. 14), Penny 
 (PhiL Trans. 1839, p. 129), Maumene (Ann. Ch. Phys. [3] xviii. 41 ; Ann. Ch. Pharm. 
 be. 173), and, lastly, by Stas (Recherches sur les Rapports reciprogucs des Poids 
 atomiques, Bruxelles, 1860). The series of operations is as follows: 
 
 1. Chlorate of potassium, KC10 3 , when heated to redness, gives off all its oxygen, 
 leaving chloride of potassium, whence the atomic weight of chloride of potassium com- 
 pared with that of oxygen is known. 
 
 2. As 1 at. chloride of potassium throws down 1 at. of silver from its solutions, the 
 determination of the quantity of chloride of silver precipitated by 1 at. chloride of 
 potassium gives the atomic weight of chloride of silver, AgCl. 
 
 Or if a known weight of silver be dissolved in nitric acid, and the quantity of 
 chloride of potassium required to precipitate it be determined, the ratio between the 
 atomic weights of silver and chloride of potassium becomes known ; whence also the 
 atomic weight of chlorine may be foiind, by determining the weight of chloride of silver 
 produced from a given quantity of silver. 
 
 3. The quantity of chloride of silver (c) produced from a given weight of silver (s) 
 is found, either by igniting silver in chlorine gas, or by dissolving it in nitric acid and 
 precipitating by hydrochloric acid : hence, the atomic weight of chloride of silver (w) 
 being previously known, that of silver (#), is found by the proportion, c : s = w : x, 
 and that of chlorine by difference ; or, the atomic weight of silver being found from 
 the quantity of chloride of potassium required to precipitate it, that of chlorine is cal- 
 culated from the composition of the chloride as just determined. 
 
 1. Determination of the Amount of Oxygen in Chlorate of Potassium. This may be 
 determined either by heating the salt to redness, or else by reducing it with hydro- 
 chloric acid, evaporating to dryness, and igniting. In carrying out the former method, 
 it is necessary to arrange the apparatus in such a manner that any small particles of 
 the salt that may be carried away by the escaping gas may be collected and weighed. 
 
 The proportions of oxygen and chloride of potassium in 100 pts. of the chlorate, 
 and the atomic weight of chloride of potassium thence determined, by the proportion 
 O 3 : KC1 = 48 : x, are as follows, according to the authorities above quoted : 
 
 Berzelius. Marignac. Penny. Maumene. Stas. 
 
 O 3 39-150 39-161 39-177 39-209 39-154 
 
 KC1 .... 60-850 60-839 60-823 60*791 60-846 
 
 100-000 100-000 100-000 100-000 100-000 
 
 Atomic weight of KC1 . 74-606 74-575 74-520 74-424 74-59. 
 
 2. Determination of the Atomic Weight of Chloride of Silver : 
 
 100 pts. of chloride of potassium yielded, by precipitation with nitrate of silver: 
 
 Berzelius. Marignac. Maumene. 
 Chloride of silver 192-4 192-35 19275 
 
 100 pts. of silver dissolved in nitric acid, require of KC1 for precipitation : 
 Marignac. Stas. 
 
 69-062 69-103 
 
 Now 1 at. chloride of potassium precipitates 1 at. silver, forming 1 at. chloride of 
 silver ; hence, according to Marignac 
 
 100 : 192-35 =, 74-575 : AgCl = 143-44. 
 
 3. By igniting 100 pts. of silver in chlorine gas, the following quantities of chloride 
 of silver are obtained : 
 
 Berzelius. Marignac. Penny. Maumene. Stas. 
 
 fl844.) (1845.) 
 
 AgCl . . 132-75 132-73 132*84 132-84 13273 132-845 
 Comparing now Marignac's first number, 132*73 (which agrees with that of Maumene 
 
906 CHLORINE : OXIDES AND OXYGEN- ACIDS. 
 
 and very nearly with that of Berzelius) with his determination of the atomic weight 
 of chloride of silver above quoted, viz. 143 '44, we find for the atomic weight of silver: 
 
 13273 
 
 Cl 
 K 
 
 143-44 = 100 : Ag = 
 143-44 - 108-06 = 
 
 108-06 
 35-38 
 
 whence : 
 
 and: K = 74-575 - 35-38 = 39-19 
 
 If, again, we start from the same atomic weight of KC1 as before, viz. 74-575, and 
 assume, according to Marignac's second determination (also that of Penny) that 100 pts. 
 silver produce 132-84 pts. chloride; also that 100 pts. silver require for precipitation 
 69-062 KC1 (Marignac), we arrive at the numbers in the left hand column of the 
 following table ; those in the right are found in like manner from the determinations 
 ofStas: 
 
 Marignac. Stas. 
 
 
 107-98 x 32-84 
 
 
 100 
 74-575 - 35-46 = 39-12 
 
 Cl 
 
 107-94 x 32-845 
 1UU 
 
 K = 74-59 - 35-45 = 39-14 
 
 Dumas (Ann. Ch. Pharm. cxiii. 21), by igniting silver in chlorine gas, found 
 that: 
 
 9-954 grm. silver gave 13-227 AgCl 
 19-976 26-542 
 
 whence, taking the atomic weight of silver at 108 (a result deduced from the analyses 
 of the nitrate by Marignac) : 
 
 The first determination gives Cl = 35-512 
 The second Cl = 35-499 
 
 Mean = 35-5 
 
 This number 35-5, being also very near to the results above detailed, is generally 
 adopted. 
 
 CHLORINE, HYDRATE OP. C1.5H 2 0. When water is introduced into a 
 vessel filled with chlorine, in quantity not exceeding 5 at. water to 1 at. chlorine, and 
 the vessel is exposed for some days to a freezing temperature, a pale yellow translucent 
 hydrate is formed, sometimes in arborescent crystalline masses, sometimes in needles 
 and rhombic octahedrons. It may be sublimed from one part of the vessel to another. 
 When gently heated in an open vessel, it is resolved into chlorine gas and aqueous 
 solution of chlorine. At 38 C. in a sealed tube, it is resolved into aqueous chlorine 
 and free liquid chlorine, which separates as a distinct stratum. The hydrate acts on 
 ammonia, ammoiiiacal salts, and alcohol in the same manner as gaseous chlorine. 
 (Faraday, Quarterly Journal of Science, xv. 71.) 
 
 CHX.ORIJXTE, OXIDES, and OXYGEN-ACIDS OF. Chlorine forms four 
 oxygen-acids, all of which may be regarded as oxides of hydrochloric acid, namely : 
 
 Hypochlorous acid HC10 Chloric acid HC10 3 
 
 Chlorous acid HC10 2 Perchloric acid HC10 4 
 
 They are obtained by the following processes : 
 
 1. Hypochlorous acid, HC1O, is produced by oxidising hydrochloric acid with per- 
 manganic acid ; and hypochlorite of potassium is formed, together with chloride, by 
 passing chlorine into a cold solution of potash : 
 
 KHO + Cl 2 = KC10 + KC1. 
 
 2. Solution of hypochlorous acid, HC10, especially at increased temperatures, is 
 converted spontaneously into chloric acid, HC10 3 , together with water, chlorine, and 
 oxygen. Moreover the solution of an alkaline hypochlorite, when boiled for some 
 time, breaks up into chlorate and chloride : 3KC10 = KC10 3 + 2KC1. 
 
 3. Chloric acid, HC10 3 , when deoxidated by nitrous acid, yields chlorous acid, 
 HC10 2 ; and conversely, chlorous acid, by its spontaneous decomposition, yields chloric 
 acid and other products. 
 
 4. Chloric acid, HC10 3 , when oxidated at the positive pole of a voltaic battery, 
 yields perchloric acid, HC10 4 . Moreover chlorate of potassium, when moderately 
 heated, breaks up into perchlorate of potassium, chloride of potassium, and oxygen. 
 
 Hypochlorites, chlorites. chlorates, and perchlorates of alkali-metal, when strongly 
 heated, are alike converted into chlorides by loss of oxygen. 
 
 The anhydride of a monobasic oxygen-acid is formed from two atoms of the acid by 
 the loss of one atom of water. The chlorine-acids should therefore yield the following 
 anhydrides : 
 
CHLORINE: OXIDES AND OXYGEN- ACIDS. 907 
 
 Acids. Anhydrides. 
 
 2HC10 - H 2 = C1 2 Hypochlorous 
 
 2HC10 2 - H'O = C1 2 3 Chlorous 
 
 2HC10 3 - H 2 = CPO 5 Chloric 
 
 2HC10 4 - H 2 = CPO 7 Perchloric 
 
 The first two anhydrides are tolerably well known, the last two have not yet been 
 obtained. We are, however, acquainted with the corresponding iodic and periodic 
 anhydrides, I 2 5 and I 2 7 , respectively. By the reabsorption of an atom of water, 
 one atom of each anhydride is reconverted into two atoms of the corresponding acid 
 CPO + H 2 O = 2HC10 
 CPO 8 + H 2 = 2HC10 2 
 (I 2 5 or) CPO 5 + H 2 = 2HC10 3 (or 2HI0 3 ) 
 (I 2 7 or) CPO 7 + H 2 = 2HC10 4 (or 2HI0 4 ) 
 
 In addition to the above anhydrides, a complete series of chlorine-oxides should 
 obviously include three other terms, thus : 
 
 CP Chlorine 
 
 CPO Hypochlorous anhydride 
 
 CPO 2 Chloric oxide ? 
 
 CPO 3 Chlorous anhydride 
 
 CPO 4 Perchloric oxide 
 
 CPO 5 Chloric anhydride 
 
 CPO 6 Hyperchloric oxide ? 
 
 CPO 7 Perchloric anhydride 
 
 Soubeiran obtained from euchlorine (p. 913) a gas which decomposed into equal 
 volumes of chlorine and oxygen, a result considered by Berzelius to be conclusive of 
 the existence of chloric oxide. Hyperchloric oxide is not improbably identical with 
 Millon's perchloro-chloric acid, C1 B 17 , or 3CP0 6 (?)^ Perchloric oxide is a very 
 well-known substance, which, moreover, appears to be identical with Millon's chloro- 
 chloric acid, C1 6 13 , or 3 CPO 4 (?) Perchloric oxide is decomposed by water into 
 chlorous and chloric acids : 
 
 CPO 4 + H 2 = HC10 2 + HC10 8 . 
 
 Hypochlorous Anhydride, Acid, and Salts. 
 
 HYPOCHLOROUS ANHYDRIDE. CPO. This gas, which was discovered by B alar d 
 in 1834 (Ann. Ch. Phys. [2] Ivii. 225), may be prepared : 1. By adding glacial phos- 
 phoric acid to a concentrated solution of hypochlorous acid standing over mercury. 
 The glacial phosphoric acid abstracts water from the hypochlorous acid, and the 
 gaseous anhydride thus produced collects in the upper part of the tube : 2HC1O - 
 H 2 = CPO. 
 
 2. By passing chlorine gas over mercuric oxide contained in a tube kept cool by 
 ice: 
 
 Hg 2 + Cl 4 = CPO + 2HgCl. 
 
 The mercuric oxide should be prepared by precipitation, and dried at a somewhat high 
 temperature, 300 C. Any excess of mercuric oxide remains combined with the re- 
 sulting mercuric chloride in the form of a brown crystalline oxychloride. The gas 
 may be collected by downward displacement, or in the mercurial trough, but it cannot 
 be kept long over mercury, as it gradually acts upon the metal. 
 
 Hypochlorous anhydride is a gas of a pale reddish-yellow colour, and a powerful 
 odour somewhat resembling that of chlorine. Its specific gravity does not appear to 
 have been determined experimentally. By calculation, supposing the molecule to oc- 
 cupy two volumes, it is ^ = 43-5, referred to hydrogen, and 3'015 re- 
 ferred to air as unity. It is so readily decomposed into two volumes of chlorine and 
 one volume of oxygen, that it cannot be preserved unchanged, even for a few hours. 
 By a slight elevation of temperature, or sometimes spontaneously, decomposition takes 
 place with explosion. In sunlight the decomposition is very rapid, but usually tranquil. 
 At the low temperature produced by a mixture of salt and ice, the gas is condensed 
 into a deep orange-coloured liquid, heavier than water, and very explosive. Both the 
 gaseous and liquid anhydride dissolve in water, undergoing decomposition and being 
 converted into hypochlorous acid : 
 
 CPO + H 2 = 2HC10. 
 
 The general reactions of the anhydride correspond with those of the acid, but are more 
 violent. 
 
 HYPOCHLOROUS ACID. HC10. This acid may be prepared : 
 
 1. From the anhydride, as just mentioned. 
 
 2. By passing air saturated with hydrochloric acid through a solution of perman- 
 
908 CHLORINE : OXIDES AND OXYGEN- ACIDS. 
 
 ganate of potassium, acidulated with sulphuric acid and heated in a water bath. The 
 distillate is a solution of hypochlorous acid formed by the direct oxidation of hydro- 
 chloric acid: HC1 + = HC10. 
 
 3. By the addition of almost any oxacid to a metallic hypochlorite. 
 
 4. By passing chlorine gas into water, holding suspended or dissolved certain me- 
 tallic oxides, hydrates, carbonates, sulphates, phosphates, &c. In practice, oxide of 
 mercury, and, according to "Williamson, carbonate of calcium, are found to be the most 
 advantageous. Either of these substances is to be agitated with water and treated with 
 chlorine gas : 
 
 Ca'CO 8 + H 2 + Cl 4 = CO 2 + 2HC10 + 2CaCL 
 
 The product of the action is to be distilled off, and if necessary concentrated by one 
 or two redistillations of the most volatile distillates. 
 
 Aqueous hypochlorous acid has a yellowish colour, an acrid taste, and a character- 
 istic sweet chloroi'd smell. The strong acid decomposes rapidly, even when kept in 
 ice. The dilute acid is more stable, but is decomposed by long boiling into chloric 
 acid, water, chlorine, and oxygen. Hypochlorous acid, like chlorine, possesses powerful 
 bleaching properties. Moreover, chloro- derivatives may be produced by its agency, 
 thus: 
 
 C 6 H 6 + HC10 = C 6 H 5 C1 + H 2 0. 
 
 Benzene. Chloro- 
 
 benzene. 
 
 Hydrochloric acid decomposes hypochlorous acid, with formation of chlorine : 
 HC10 + HC1 = H 2 + CP. 
 
 Hypochlorous acid is a very powerful oxidising agent. It rapidly converts many of 
 the elements, iodine, selenium, and arsenic, for instance, into their highest oxides, at 
 the same time liberating chlorine. The metals differ much from one another in the 
 nature of their respective reactions with hypochlorous acid. Those which decompose 
 the acid form oxides, as does iron, or oxychlorides, as do copper and mercury. Silver, 
 indeed, forms a chloride and liberates oxygen, thus : 
 
 Ag 2 + 2HC10 = 2AgCl + H 2 + 0. 
 
 Many metallic oxides, those of manganese, cobalt, and lead, for example, are per- 
 oxidised, with liberation of chlorine ; but oxide of silver is converted into chloride of 
 silver, with liberation of oxygen : 
 
 Ag 2 + 2HC10 = 2AgCl + H 2 + 0*. 
 
 HYPOCHZOIHTES. 1. Pure hypochlorites are made by neutralising hypochlorous 
 acid with hydrates, such, for instance, as those of sodium, potassium, calcium, barium, 
 magnesium, zinc, copper, &c. 2. Hypochlorites are usually prepared by passing 
 chlorine gas into solutions of hydrated or carbonated alkali, or over the dry hydrates 
 of the earths. By this process, a chloride and a hypochlorite are simultaneously pro- 
 duced. The reaction is believed to be as follows : 
 
 Cl 2 + 2CaHO = CaCl + CaCIO + H 2 0. 
 
 These mixed compounds constitute the bleaching and disinfecting salts of commerce, 
 the properties of which were known as early as the time of Berthollet. They were 
 long regarded as chlorides of the alkali- and earth-metals, and known as chloride of 
 lime, chloride of soda, &c., till Berzelius suggested the idea that they might be mix- 
 tures of metallic chlorides with alkaline chlorites (M 2 O.CFO S ). Balard, in 1834, showed 
 that their properties are best explained by regarding them as mixtures of chlorides 
 and hypochlorites. The only objections to this view are that alcohol does not extract 
 chloride of calcium from bleaching powder, as we should a priori expect, and, unlike 
 mixtures containing chloride of calcium, bleaching powder is not deliquescent. These 
 anomalies may possibly be due to the formation of a double salt, containing chloride 
 and hypochlorite of calcium in chemical combination with one another. 
 
 The pure hypochlorites, when acted upon by sulphuric acid, or even by carbonic 
 acid, liberate hypochlorous acid, thus : 
 
 2CaC10 + H 2 SO* = 2HC10 + Ca 2 S0 4 . 
 
 The mixed salts behave in the same manner, provided the sulphuric acid is not in 
 excess ; but otherwise chlorine, and not hypochlorous acid, is evolved : 
 
 CaCIO + CaCl + H 2 S0 4 = H 2 + Cl 2 + Ca 2 S0 4 . 
 
 The sulphuric acid acts first upon the hypochlorite to liberate hypochlorous acid, and 
 then upon the chloride to liberate hydrochloric acid, the co-existence of which two 
 acids cannot occur, owing to their mutual decomposition into water and free chlorine, 
 
CHLORINE: OXIDES AND OXYGEN- ACIDS. 909 
 
 as we have already seen. Hydrochloric acid can liberate hypochlorous acid from the 
 pure or mixed salts, thus : NaClO + HC1 = HC10 + NaCl. But any excess of hydro- 
 chloric acid immediately reacts upon the nascent hypochlorous acid to form water and 
 chlorine. Solutions of the hypochlorites, either pure or commercial, are very unstable, 
 but are more permanent in the presence of free alkali. They graduaDy give off oxygen 
 gas, and finally yield mixtures of chloride and chlorate. Their decomposition takes 
 place very definitely at a boiling temperature, thus : 
 
 SCaCIO = CaCIO 3 + 2Cal. 
 
 Of themselves they act as bleaching agents, probably by evolution of oxygen ; but the 
 effects produced by acidifying their solutions, and thereby liberating hypochlorous 
 acid, are much more rapid. With most metallic oxides and salts, the hypochlorites 
 react as does hypochlorous acid upon the oxides. They convert oxide of silver, for 
 instance, into chloride of silver, with liberation of oxygen : 
 
 Ag-0 + 2NaC10 -t- H 2 = 2AgCl + 2NaHO + O 2 ; 
 
 iind sulphate of manganese into hydrated peroxide of manganese, with liberation of 
 chlorine : 
 
 Mn 2 S0 4 + 2NaC10 + H 2 - Na 2 S0 4 + 2MnH0 2 + Cl 2 . 
 
 The characters of the individual salts will be described in a distinct article (HYPO- 
 CHLORITES). For the valuation of hypochlorites see p. 904. 
 
 Chlorous Anhydride, Acid, and Salts. 
 
 CHLOROUS ANHYDRIDE. C1 2 3 . This gas, discovered by Millon (Ann. Ch. 
 Pharm. xlvi. 298), results from the spontaneous decomposition of chlorous acid, which 
 is a somewhat ill-defined and unstable substance : 
 
 2HC10 2 = H 2 + C1 2 S . 
 
 It is also produced by the reaction of chloric acid with nitrous acid or anhydride : 
 2HN0 2 + 2HC10 3 = 2HN0 3 + H 2 0+ CPO 3 . 
 
 Instead of preformed chloric acid and nitrous acid or anhydride, a mixture of chlorate 
 of potassium, nitric acid, and arsenious anhydride is usually employed. The nitric 
 acid is first reduced by the arsenious anhydride to the state of nitrous acid, which is the 
 real deoxygenant of the liberated chloric acid : 
 
 As 2 3 + 2H 2 + 2KC10 3 = 2KH 2 As0 4 + CPO 3 . 
 
 The reaction is effected by the application of a very gentle heat. The arsenious anhy- 
 dride may be replaced by tartaric acid or other deoxidising agent. The gas must be 
 collected by displacement. 
 
 Chloroxis anhydride is a yellowish green gas, permanent in a freezing mixture of ice 
 and salt, but liquefiable by extreme cold. Its specific gravity, calculated for a conden- 
 sation to 2 vols., is = 59'5 referred to hydrogen, and 4-123 referred to air. 
 
 At slightly elevated temperatures, 57 C. and upwards, it is decomposed, with explo- 
 sion, into chlorine and oxygen. It dissolves freely in water or in solutions of the alka- 
 line and earth-alkaline hydrates, gradually forming chlorous acid or chlorites. 
 
 CHLOROUS ACID. HC10 a . This acid may be prepared by condensing chlorous 
 anhydride in water : 
 
 C1 2 3 + H 2 O = 2HC10 2 . 
 
 or by acting upon a chlorite with some diluted acid, such as sulphuric or phosphoric : 
 2PbC10 2 + H 2 S0 4 = 2HC10 8 + Pb 2 S0 4 . 
 
 The acid, or its concentrated solution, is a greenish yellow liquid of great tinctorial 
 power, and having strong bleaching and oxidising properties. It does not decompose 
 carbonates, but reacts slowly with caustic alkalis and earths to form chlorites. 
 
 CHLORITES. MC10 2 . The alkaline and earthy chlorites are formed as above de- 
 scribed. They also result from the action of perchloric oxide on bases (p. 912). They 
 are, for the most part, soluble, crystallisable, colourless salts, possessed of bleaching 
 properties. The insoluble chlorites of silver, lead, and other metals are produced by 
 double decomposition : 
 
 AgNO 8 -i- KC10 = KNO S + AgCIO 2 . 
 
 The chlorites are decomposed even by carbonic acid. 
 
 For the characters of the individual chlorites, see page 914. 
 
910 CHLORINE : OXIDES AND OXYGEN-ACIDS. 
 
 Chloric Acid and Salts. 
 
 CHLORIC ACID. HC10 3 . (Vauquelin, Ann. Chim. xcv. 91; Serullas, Ann. Ch. 
 Phys. [2] xlv. 204, 270.) 1. The acid is liberated from chlorates by the addition of a 
 stronger acid. It is found advantageous to use equivalent quantities of chlorate of 
 barium and sulphuric acid : 
 
 2BaC10 8 + H 2 SO* = 2HC10 8 h Ba'SO 4 . 
 
 The solution of chloric acid is separated from the insoluble sulphate of barium by fil- 
 tration, and concentrated by evaporation in vacuo. 2. This acid also results from the 
 spontaneous decomposition of solutions of hypochlorous acid, chlorous acid, and per- 
 oxide of chlorine. 
 
 Chloric acid is a colourless syrupy liquid, having a strong acid reaction, and when 
 warm, a pungent chloroid smell. It is decomposed by organic matter, with charring, 
 and frequently even with ignition. It is somewhat unstable at ordinary temperatures. 
 At 40 C. it undergoes marked decomposition, and at a boiling heat is rapidly con- 
 verted into perchloric acid, water, chlorine, and oxygen. It is a very powerful oxidis- 
 ing and bleaching agent. It is decomposed by hydrochloric, sulphydric, and sulphurous 
 acids, with liberation of chlorine. 
 
 CHLORATES. MC10 8 . 1 . These salts may be prepared by saturating the acid with 
 bases. Chlorate of barium is usually made by this process (p. 885). 
 
 2. Zinc, and one or two other metals, dissolve in chloric acid to form chlorates, 
 thus : HC10 3 + Zn = ZnCIO 3 + H ; but a part of the acid always undergoes a more 
 complex decomposition. 
 
 3. Alkaline chlorates are produced by boiling solutions of the hypochlorites, or, what 
 comes to the same thing, by passing chlorine into caustic or carbonated alkali, and 
 boiling the resulting liquid : 3KC10 = KC10 3 + 2KC1. The chlorate is separated from 
 the chloride by crystallisation. 
 
 The chlorates are chiefly interesting as sources of oxygen gas. Chlorate of potassium 
 and most chlorates are decomposed by heat into chloride and oxygen, thus, KC10 3 = 
 KC1 -I- s ; but the chlorates of the earth-metals yield oxygen, chlorine, and metallic 
 oxide: 2MgC10 3 = Mg 8 + Cl 2 + O 5 . Prior to the ultimate decomposition of chlorate 
 of potassium, a portion of perchlorate is produced. The fused chlorates are powerful 
 oxidising agents. Mixtures of chlorate with combustible substances, such as sulphur, 
 sulphide of antimony, and sugar, explode violently on the application of heat, or by 
 percussion. Strong sulphuric acid liberates perchloric oxide from the chlorates, and, 
 by its action on mixtures of chlorate with combustible matters, frequently induces 
 combustion. Nitric acid reacts with chlorate of potassium to form nitrate of potassium, 
 perchlorate of potassium, and free chlorine and oxygen gases. Hydrochloric acid pro- 
 duces euchlorine, which is a gaseous mixture of chlorine and perchloric oxide. A 
 mixture of chlorate of potassium and hydrochloric acid is much used for oxidising 
 mineral and organic compounds. All the chlorates are soluble in water, and hence do 
 not precipitate the salts of the heavy metals. Chlorate of potassium, the most im- 
 portant member of the class, is one of the least soluble. Unlike the hypochlorites and 
 the chlorites, the chlorates do not bleach until after the addition of an acid. [For the 
 description of the individual salts, see pp. 885 890]. 
 
 Perchloric Acid and Salts. 
 
 PERCHLORIC ACID. HC10 4 . This acid was discovered in 1815 by Count Stadi on 
 (Grilb. Ann. Hi. 197), afterwards more particularly examined by Serullas (Ann. Ch. 
 Phys. [2] xlv. 270; xlvi. 294, 323), and quite recently by Roscoe*, who has obtained 
 it in definite form. It is produced: 1. By the electrolysis of chloric acid. Oxygen 
 and chlorine are evolved in small quantities at the positive pole, and hydrogen at the 
 negative pole ; but the greater part of the oxygen remains in the liquid, and converts 
 the chloric into perchloric acid (Stadion). 2. By the distillation of chloric acid 
 (p. 910). 3. By the action of sulphuric acid upon chlorate of potassium (see PER- 
 CHLORIC OXIDE, p. 912). 4. By the action of certain acids upon the perchlorates. 
 Thus, fluosilicic may be added to perchlorate of potassium, and the resulting insoluble 
 fluosilicate of potassium filtered off from the solution of perchloric acid; or sulphuric 
 instead of fluosilicic acid may be employed, and the volatile perchloric acid distilled 
 off from the sulphate of potassium. (Serullas.) 
 
 Aqueous perchloric acid obtained by either of these methods may be concentrated 
 by boiling till it attains a temperature of 203 C., after which it passes over unchanged 
 in the form of an oily liquid containing 70-3 per cent., HC10 4 . If this oily acid be 
 
 * These results, which are not yet published, have been kindly communicated by Professor Roscoe. 
 
CHLORINE : OXIDES AND OXYGEN- ACIDS. 91 1 
 
 distilled with twice its volume of strong sulphuric acid, it gives up its water to the 
 latter, and perchloric acid passes over nearly pure in the form of a yellowish strongly 
 fuming liquid. On continuing the distillation, the oily acid above-mentioned begins 
 to pass over ; but as soon as it comes in contact with the more volatile portion of the 
 distillate, the two unite into a crystalline mass consisting of a hydrate, HC10 4 .H 2 O. 
 Both these products are, however, contaminated with sulphuric acid mechanically 
 carried over. To obtain the volatile liquid in a pure state, the crystals must be redis- 
 tilled per se. They then split up into pure perchloric acid, HC10 4 , which is obtained 
 as the first produce of the distillation, and the oily acid, which contains a larger pro- 
 portion of water, and passes over afterwards. (Koscoe.) 
 
 Pure perchloric acid, HC1O 4 , is a colourless very volatile liquid, having a specific 
 gravity of 1 '7 82 at 15*5 C. Its vapour is likewise colourless and transparent, but on 
 coming in contact with the air, it absorbs water, and forms dense white fumes. Per- 
 chloric acid in this state is one of the most powerful oxidising agents known ; a single 
 drop brought in contact with charcoal, paper, wood, or other organic substance, imme- 
 diately causes an explosive combustion, which in violence does not fall far short 
 of the sudden decomposition of chloride of nitrogen. The acid unites also very 
 energetically with water, a violent hissing noise being produced. The greatest care 
 must be taken in working with this substance, as one drop falling on the skin produces 
 cauterisation,. and leaves a wound which does not heal for months. Like pure nitric 
 acid, this acid cannot be distilled by itself without undergoing decomposition, a sin- 
 gular black explosive body being produced when it is boiled. It likewise undergoes 
 spontaneous decomposition at the ordinary temperature, the bulbs in which it was 
 sealed exploding even when kept in the dark. 
 
 The composition of pure perchloric acid was determined by neutralising it with car- 
 bonate of potassium, adding acetic acid to acid reaction, evaporating to dryness, throw- 
 ing the perchlorate of potassium on a weighed filter, washing out the soluble acetate 
 with absolute alcohol, and determining the composition of the potassium salt thus pro- 
 duced. In this manner results agreeing closely with the theory were obtained. Thus, 
 1*2185 grm. of acid gave 1"6785 of potassium salt, calculation requiring 1-6876. Of 
 this salt, 0-966 grm. heated with peroxide of iron lost 0-444 grm., and the residual KC1 
 required 0-744 grm. pure silver for complete precipitation. Now 0*744 Ag is equiva- 
 lent to 0-513 KC1, and by calculation 0-966 KC10 4 should yield 0-519 KC1. (Eoscoe.) 
 
 The Hydrate, HC10 4 .H'-'O (containing 84-81 per cent. HC10 4 ), is obtained in the 
 pure state by adding water to the pure acid HC10 4 . It is a white, solid, crystalline 
 substance, which melts at 50 C., and undergoes decomposition when heated to 110, 
 splitting up into the pure acid and an aqueous oily acid. Its composition was deter- 
 mined by the method adopted in the case of the pure acid. The specific gravity of 
 the liquid hydrate at 50 C. is 1-811. Although not so violent in its action on organic 
 matter as the pure acid, the fused hydrate when brought into contact with paper or 
 wood, induces immediate combustion, and when dropped into water, combines therewith 
 making a hissing noise. 
 
 When it is distilled, the temperature is found to rise gradually to 203 C., at which 
 point it remains constant, a heavy oily liquid then passing over, which in outward ap- 
 pearance cannot be distinguished from sulphuric acid. This acid contains 72-1 per 
 cent, of HC10 4 , and does not therefore correspond to any definite hydrate, HC1O 4 . 2H 2 O 
 requiring 73-6 per cent. HC10 4 , and HC10*.3H 2 0, requiring 65'05 per cent, HC10 4 . 
 If aqueous perchloric acid be concentrated by boiling, water goes off, and the tempera- 
 ture rises to 200 C., when the acid is likewise found to contain 72' 1 per cent, of 
 HC1O 4 . Hence an aqueous acid loses water, and the crystallised hydrate loses per- 
 chloric acid on boiling under the ordinary atmospheric pressure, until both arrive at a 
 point when no further change takes place, and an acid containing 72'1 per cent. 
 HC10 4 passes off unchanged. (Eoscoe.) 
 
 Aqueous perchloric acid reddens litmus strongly, but does not bleach. It dissolves 
 zinc and iron, with evolution of hydrogen, forming perchlorates. When dilute, it is 
 unaffected by sulphydric and sulphurous acids, which reduce all other oxacids of 
 chlorine. 
 
 PER CHL OB AXES. These salts are produced : 1. By the reaction of perchloric acid 
 with metals, oxides, sulphides, or carbonates, or of perchlorate of barium with sulphates, 
 thus: 
 
 HC10 4 + BaHO = BaCIO 4 + H 2 O 
 2BaC10 4 + Na 2 S0 4 = 2NaC10< + Ba 2 S0 4 . 
 
 2. By the decomposition of chlorates. During the decomposition of chlorate of potas- 
 sium by heat, and after a considerable evolution of oxygen has taken place, the previously 
 fused salt is observed to assume a pasty condition, and if the heat be then discontinued, 
 the residue will be found to consist principally of perchlorate and chloride of potassium, 
 
912 CHLORINE : OXIDES AND OXYGEN-ACIDS. 
 
 which two salts may be separated from one another by solution and crystallisation, the 
 perchlorate being much the less soluble : 
 
 2KC10 3 = KC10 4 + KC1 + O 2 . 
 Or, the chlorate of potassium may be decomposed by nitric acid : 
 
 3KC10 3 + 2HN0 3 = KC10 4 + 2KN0 3 + H 2 + Cl 2 + 0*, 
 and the resulting nitrate and perchlorate of potassium separated by crystallisation. 
 
 Perchlorate of potassium is sparingly soluble in cold water ; but the perchlorates 
 in general are soluble, crystalline, deliquescent salts. They deflagrate, though less 
 violently than the chlorates, when thrown on ignited charcoal. They require a stronger 
 heat than do the chlorates to effect their decomposition into chloride and oxygen. Sul- 
 phuric acid liberates perchloric acid from the perchlorates, but not until the tempera- 
 ture rises to 100 C. : other acids liberate perchloric acid, only when they form insoluble 
 salts with the bases of the perchlorates. Hence, unlike chlorates, the perchlorates do 
 not assume a yellow colour when acted upon by sulphuric or hydrochloric acid. [For 
 the description of the individual salts, see PERCHLORATES.] 
 
 Perchloric Oxide and Euchlorine. 
 
 PERCHLORIC OXIDE. C1 2 4 . This very explosive compound, which was discovered 
 by Count Stadion (loc. cit.}, may be prepared by the action of strong sulphuric acid 
 upon chlorate of potassium, whereby perchlorate of potassium, acid sulphate of potas- 
 sium, water, and perchloric oxide are produced : 
 
 3KC10 8 + 2H 2 SO* = KC10 4 + 2KHS0 4 + H 2 + CPO 1 . 
 
 The chlorate should be purified by recrystallisation, fused after drying, at the lowest 
 adequate temperature, and then finely pulverised. The powder must be added little 
 by little to sulphuric acid, made cool by a mixture of ice and salt, until a pasty mass 
 is produced. This is to be set aside for some time, and afterwards, by means of a water- 
 bath, to be very gently heated in a retort. The evolved gaseous perchloric oxide must 
 be collected by downward displacement. Calvert has shown that perchloric oxide, 
 mixed with carbonic acid, may be readily obtained by heating finely powdered chlorate 
 of potassium with crystallised oxalic acid to a temperature of 70 C. (p. 888). 
 
 Perchloric oxide is a gas of a bright yellow colour, and sweet aromatic smell. At the 
 low temperature produced by a mixture of salt and ice, it is condensed into a yellowish 
 highly explosive liquid. Faraday succeeded in solidifying it by means of the intense 
 cold produced by the evaporation of solid carbonic acid and ether. In daylight the 
 gas undergoes spontaneous decomposition into chlorine and oxygen. This decompo- 
 sition is frequently, and, when induced by elevation of temperature, almost invariably, 
 attended by a violent explosion. The contact of highly combustible matters also 
 determines an explosion. Liquid perchloric oxide unites with water at a tempera- 
 ture of C., to form a solid hydrate. At ordinary temperatures, water dissolves several 
 times its volume of the gas. The solution has a yellow colour, is devoid of acid re- 
 action, bleaches powerfully, and is very unstable, being decomposed into chloric acid, 
 chlorous acid, and other products. Perchloric oxide is absorbed by alkaline solutions. 
 with formation of chlorate and chlorite : 
 
 2KHO + C1 2 4 = KC10 2 + KC10 8 + H 2 0. 
 
 The molecule of perchloric oxide C1 2 4 , like the molecule of chlorine Cl 2 , seems to be 
 binary or dyadic, and to halve itself in the act of combination. In this manner, the 
 correlations of chlorite and chlorate would correspond with those of chloride and hy- 
 pochlorite, thus : 
 
 Chloride Q[ | Hypochlorite ^JO. Chlorite ^2 j Chlorate 
 
 EUCHLORIN E. When chlorate of potassium is acted upon by hydrochloric acid, a 
 bright yellow gas, called euchlorine, is liberated. This gas contains chlorine and oxy- 
 gen in the same proportions as hypochlorous anhydride, C1 2 0, but despite its uniformity 
 of composition, it is evidently a mixture, probably of chlorine and perchloric oxide. 
 The following equation is believed to express its formation correctly : 
 4KC10 3 + 12HC1 = 4KC1 + 6H 2 + (9C1 + 3C10 2 ). 
 
 This mixed gas has a sweet aromatic smell, and powerful bleaching properties. By 
 passing it through a U-tube immersed in a mixture of salt and ice, the perchloric oxide 
 is separated in the liquid state from the free uncondensed chlorine. According to 
 Mil Ion, the liquid perchloric oxide obtained by cooling euchlorine, differs from the 
 liquid perchloric oxide obtained by means of sulphuric acid and chlorate of potassium, 
 in its somewhat greater stability, in its somewhat higher boiling point, and in the 
 
CHLORINE: SULPHIDES OF CHLORITE. 9J3 
 
 circumstance that, although, like the normal compound, it is decomposed by alkalis 
 into chlorate and chlorite, yet that, unlike the normal compound, it yields two equi- 
 valents of the former for one of the latter salt. Hence Millon assigns to it the formula 
 Cl0 13 = 3CF0 5 ? 
 
 C1 6 1S + 6KHO = 3H 2 + 4KC10 3 + 2KC10 2 , 
 
 but these differences may probably be due to differences in the purity of these two 
 bodies. Moreover, perchloric oxide is a very difficult subject to investigate, and the 
 descriptions of different experimentalists vary considerably from one another. (See 
 Gmclin's Handbook, ii. 304, 310.) W. O. 
 
 CHLORINE, SULPHIDES OF. Two only of these compounds are known in the 
 free state, viz. SCI and SOP. The former is analogous in composition to hypochlorous 
 anhydride, CIO, but exhibits no analogy whatever to that compound in its properties. 
 It is doubtful indeed whether the sulphur or the chlorine in these compounds is the 
 negative element ; but they are usually regarded as chlorides of sulphur, and as such 
 will be more fully considered. (See- SULPHUR.) 
 
 Similar observations apply to the compounds of chlorine and selenium. 
 
 CHX.ORXODOFORM. Dichlorinatcd Iodide of Methyl. CHCPI. (Serullas, 
 Ann. Ch. Phys. [2] xxv. 314; xxxix. 225. Mitscherlich, Pogg. Ann. xi. 164. 
 Bouchardat, Ann. Ch. Pharm. xxii. 2229. Grm. vii. 337). This compound was dis- 
 covered by Serullas in 1824, but its composition was first correctly ascertained by 
 Bouchardat. It is obtained by distilling iodoform with an equal weight of penta- 
 chloride of phosphorus or mercuric chloride. The materials are intimately mixed, and 
 distilled in a retort ; the dark red distillate is decolorised with aqueous potash, then 
 shaken up with strong sulphuric acid, to free it from chloride of ethylene, afterwards 
 separated from the sulphuric acid by a tap-funnel, and purified by rectification. 
 
 Chloriodoform is a transparent pale yellow liquid of specific gravity T96, having an 
 aromatic odour and saccharine taste, and becoming rose-coloured by exposure to the 
 air. It remains fluid at the lowest temperatures, and is not decomposed' by distillation. 
 It is but sparingly soluble in water. Heated with strong aqueous potash, or with 
 alcoholic potash, it yields formate, chloride, and iodide of potassium : 
 
 CHCPI + 2K 2 = CILKO 2 + 2KC1 + KI. 
 In contact with chlorine gas, it solidifies and yields trichloride of iodine. 
 
 CHXiORXSAlMEXC ACID and CHLORISAMirDE. See ISAMIC ACID and ISA- 
 HIDE. 
 
 CHX.ORXSATXC ACID. See ISATIC ACID. 
 
 CHLORISATYDE and CHLORISATirDIC ACID. See ISATYDE and ISA- 
 TIC ACID. 
 
 CHLOHISATIKT. See IsATIN. 
 
 CHX.ORXSATOSUX.PHXTES. See IsATOSULPHITES. 
 
 CHIiORITE. Leuchtenbcrgite, Pennine. This name is applied to certain sili- 
 cates of magnesia and alumina occurring in plutonic formations, and forming the cha- 
 racteristic ingredients of chlorite slate. It formerly included ripidolite and clinochlore, 
 and is still applied to at least two minerals, differing in crystalline form, and some- 
 what also in chemical composition. Chlorite from Achmatowsk in the Ural is mono- 
 clinic ; but the variety called Pennine, from Zermatt in the Valais, is hexagonal, generally 
 forming six-sided tables with perpendicular edges, oP . oo P, or with bevelled edges, 
 oP . P, where P denotes a six-sided pyramid with basal edges of 106 50' and pyramidal 
 edges of 132 40' ; also with other faces subordinate. Cleavage perfect, parallel Lo the 
 base. The crystals are sometimes imbedded singly, but more frequently grouped in 
 spherical, conical, or vermiform masses ; also in minute scales, forming a deposit on other 
 minerals. Specific gravity 2*65 to 2*85. Hardness 2'0 to 2'5. Flexible in thin laminae, 
 but not elastic. Colour various shades of green, from leek to blackish green. Small 
 crystals are dichromatic, appearing red when viewed in a direction perpendicular to 
 the vertical axis. Lustre nacreous on the basal faces, vitreous to waxy on the 
 others. Transparent in thin laminae, but generally translucent, and transparent on 
 the edges only. 
 
 All varieties of chlorite give off water when heated in a tube, and melt with difficulty 
 before the blowpipe to a black slag, sometimes magnetic. The mineral gives with fluxes 
 the reactions of iron, more rarely that of chromium, and is perfectly decomposible by 
 sulphuric acid. 
 
 The several varieties of chlorite exhibit considerable diversity of composition ; the 
 essential constituents are silica, alumina, magnesia, and water, the alumina, however, 
 being often more or less replaced by ferric oxide and the magnesia by ferrous oxide. 
 The following are analyses: 1. Varrentrapp (Pogg. Ann. xlviii. 185). 2. Kobell 
 
 VOL. I. 3 N 
 
914 
 
 CHLORITES. 
 
 (J. pr. Chem. xvi. 470). 3. Briiel (Pogg. Ann. xlviii.) 4. Delesse (Ann. Ch. Phys. 
 [3] ix. 396). 5, 6. Marignac (ibid. x. 430). 7, 8. Hermann (J. pr. Chem. xi. 
 13). 9. Schweizer (Pogg. Ann. 1. 626). 10, 11. Marignac (loc. tit.) 
 
 Si 02 
 
 AHQ3 
 
 Mg^O 
 
 Fe0 
 
 1. Achmatowsk 30-38 
 
 16-96 
 
 3397 
 
 
 
 2. Schwarzenstein 
 
 32-68 
 
 14-57 
 
 33-11 
 
 ^ m 
 
 3. Zillerthal . 
 
 31-47 
 
 16-67 
 
 3256 
 
 _ 
 
 4. Pyrenees 
 5. Ala (Piedmont) 
 
 32-1 
 
 30-01 
 
 18-5 
 19-11 
 
 367 
 33-15 
 
 4*1 
 
 6. Slatoust (Ural) 
 
 30-2-y 
 
 19-89 
 
 33-13 
 
 4-42 
 
 7. white 
 
 30-80 
 
 17-27 
 
 37-07 
 
 1-37 
 
 8. l.euchtenbergite 
 
 32-35 
 
 18-00 
 
 32-29 
 
 4-37 
 
 9. Zermatt (Pennine) 33'07 
 
 9-69 
 
 32-34 
 
 
 10. 33-36 
 
 13-24 
 
 34 21 
 
 bl)3 
 
 11. Binnen 33-95 
 
 1346 
 
 3371 
 
 6 12 
 
 Fe 2 O 
 
 Mn2Q 
 
 H2Q 
 
 
 
 4-37 
 
 
 
 12-63 
 
 = 98-31 
 
 
 5-97 
 
 0-?8 
 
 12-10 
 
 insol. 1-02 
 
 = 99'73 
 
 5-97 
 
 0-01 
 
 12-42 
 
 = 99-11 
 
 
 0-6 
 
 __ 
 
 121 
 
 = 10 
 
 
 _ 
 
 _ 
 
 12-53 
 
 = 99-60 
 
 
 - 
 
 __ 
 
 12-54 
 
 = 100-25 
 
 
 __ 
 
 __ 
 
 12-30 
 
 = 98-82 
 
 
 __ 
 
 __ 
 
 12-50 
 
 = 99-51 
 
 
 1136 
 
 _ 
 
 12-58 
 
 = 99-08 
 
 
 
 __ 
 
 12-80 
 
 Cr2Q3 0-20 
 
 = 99-74 
 
 
 
 _ 
 
 12-52 
 
 M 024 
 
 = 100 
 
 These numbers may be approximately represented by the formula 2(3M 2 O.SiO 2 ) + 
 Al 4 O s .Si0 8 + 4aq. which, if M denotes magnesium, requires 30-82 SiO 2 , 17'14 Al'O 3 , 
 
 in various parts of the Eastern United States. (Dana, ii. 294; Bammelsbery'* 
 Mineralchemie, p. 534; Handw. d. Chem. 2 te Aufl. ii. [2] 1106.) 
 
 CHLORITE EAETH is earthy chlorite in the older sense of the word, without regard 
 to the distinction between chlorite and ripidolite, because in the earthy state the two 
 minerals can scarcely be distinguished. 
 
 CHLORITE FERRUGINOUS. Ddcssite. This mineral occurs in the amygdaloi'dal por- 
 phyry of Oberstein and Zwickau. It is massive, with short fibrous or scaly feathery 
 texture. Specific gravity 2*89. Hardness 2'5. Colour olive-green to blackish-groen. 
 According to Delesse (Ann. Min. [4] xvi. 520) it contains 29'45 percent. SiO 2 , 18-25 
 Al'O', 8-17 Fe 4 3 , 15-12 Fe 2 0, 15-32 Mg 2 0, 0'45 Ca'O, and 12-57 water (= 99-33), 
 which may be approximately represented by the general formula 2(2M 2 O.M 4 3 .28iO-) 
 + 5 aq. Grengesite, from Grengesberg in Dalecarlia, containing, according to Hisinger, 
 27*01 SiO 2 , 14-31 A1 4 3 , 2'18 Mn 4 3 , 25'63 Fe 2 0, 14-31 Mg 2 0, and 12-53 water, ap- 
 pears to be related to it. (Dana, ii. 296; Eammelsberg 1 s Mineralchemie, 540.) 
 
 CHLORITE SLATE. This name is applied to chlorite occurring in mountain masses, 
 including, however, those which are made up in like manner of ripidolite. 
 
 CHLORITE-SPAR. See CHLORITOIDE. 
 
 CHI.ORITES. MC10 2 . (Millon, Ann. Ch. Pys. [3] vii. 298; Ann. Ch.Pharm. 
 xlvi. 281.) Salts of chlorous acid. Their general properties arc described, together 
 with those of the acid, at page 910. Only a few of them have been studied indi- 
 vidually. 
 
 CHLORITE OF BARIUM. BaCIO 2 . Obtained by saturating chlorous acid with 
 baryta. By quickly evaporating the solution and finishing the evaporation in vacuo, it 
 may be obtained crystallised and free from chlorite. It dissolves readily in water, and 
 decomposes at 235 C. 
 
 CHLORITE OF LEAD, PbCIO 2 , is prepared by adding nitrate of lead to chlorous 
 acid nearly neutralised with lime or baryta, washing the sulphur-yellow scaly precipitate 
 thereby produced, and drying it. If the solution be warmed before adding the nitrate 
 of lead, the chlorite of lead is deposited in larger crystalline scales. The salt decom- 
 poses with a kind of explosion at 126 C. (Millon), at 100 (Schiel, Ann. Ch.Pharm. 
 cix. 317). It sets fire to flowers of sulphur when triturated therewith (Millon) ; when 
 rather large quantities of the salt are mixed with sulphur or a sulphide of an electro- 
 negative metal, the mixture takes fire spontaneously after some time (Schiel). Chlo- 
 rite of lead introduced into sulphydric acid gas blackens at first, but afterwards 
 turns white, from formation of sulphate of lead. With a mixture of equal parts of 
 strong sulphuric acid and water, it evolves pure chlorous anhydride (C1 2 S ), especially 
 between 40 and 5.0 C., and yields 8875 per cent, of sulphate of lead. (Millon.) 
 
 The mother-liquor filtered from the precipitate of chlorite of lead in the above- 
 d escribed mode of preparation, deposits on the sides of the vessels, small sparingly so- 
 luble yellowish crystals, which appear to be a compound of chlorite and chloride of lead. 
 (Schiel.) 
 
 CHLORITE OF POTASSIUM. KC10 2 . Potash-ley, mixed with excess of chlorous 
 acid, forms a deep red liquid, which, when concentrated, gives off chlorous anhydride, 
 and leaves neutral chlorite of potassium in the form of a very deliquescent salt. If, on 
 the contrary, chlorous acid be gradually added to an excess of hydrate of potassium, the 
 formation of the neutral salt takes a longer time, and even after the liquid has become 
 colourless, the presence of free chlorous acid may be detected by its power of convert- 
 ing nitrate of lead into the peroxide. The saline solution mast be quickly evaporated, 
 
CHLORITOIDE - CHLOROCAFFEINE. 915 
 
 otherwise the chlorite of potassium will be completely resolved into chloride and 
 chlorate. The same decomposition takes place if it be heated to 160 C. (Millon.) 
 
 CHLORITE OF SILVEB. AgCIO 2 . Prepared by mixing a soluble chlorite containing 
 a slight excess of base with nitrate of silver, and boiling the resulting precipitate of 
 chlorite and oxide of silver with water. The solution on cooling deposits the salt in 
 yellow crystalline scales. At 105 C. it decomposes with explosion. A mixture of it 
 with sulphur takes fire when triturated with a glass rod. In preparing the salt, an 
 excess of chlorous acid must be avoided, as it would thereby be quickly resolved into 
 chlorate and chloride. (Millon.) 
 
 CHLOBITE OF SODIUM. NaCIO 2 . Deliquescent. Resembles the potassium-salt, 
 but is not decomposed by a heat below 250 C. (Millon.) 
 
 CHLOBITE OF STBONTIUM. SrCIO 2 . Deliquescent. Decomposes at 208 C. 
 (Millon.) 
 
 CHXiORXTOXDE. Chlorite Spar, Barytophyttite, Masonite. A coarsely foliated 
 massive silicate of alumina and iron found at Kosoibrod in the Ural, Bregratten in the 
 Tyrol, and GKimmuch-dagh in Asia Minor. Its specific gravity is 3-557 ; hardness 5'5 
 to 6 ; colour dark grey or greenish black ; lustre faint and pearly. Gives off water 
 when heated in a tube, is infusible before the blowpipe, but becomes darker and mag- 
 netic. It dissolves completely in sulphuric acid. 
 
 Allied to chloritoide are : Masonite, from Ehode Island, which fuses with difficulty 
 to a dark green enamel, and Sismondine, a dark greyish or blackish green mineral of 
 specific gravity 3 '565 and hardness 5'5. Nearly infusible before the blowpipe, occur- 
 ing in the chlorite slate of St. Marcel. 
 
 Analysis: Chlorito'ide. 1. 0. Erdmann (J. pr. Chem. vi. 86). 2. Bonsdorff 
 (Berz. Jahresber. xviii. 233). 3. Hermann (J. pr. Chem. liii. 13). 4. Smith 
 (Ann. Min. [4] xviii. 300). 5. Kobell (J. pr. Chem. Iviii. 40. Masonite, Whitney, 
 (Proc. Boston Soc. Nat. Hist. 1849, p. 100). Sismondine, Delesse (Ann. Ch. Phys. 
 [3] ix. 385). 
 
 Chloritoide Si 2 Al< 3 Fe4 3 Fe2 Ma2 
 
 1. Kosoibrod . 24-90 4f>'20 28-89 = 99'99 
 
 2. .- 27-48 35-57 27'05 0'30 4 29 6'95 = 101-64 
 
 3. . 24-54 30-72 17'8 17'80 375 6'38 = 9J'97 
 
 4. Gummuch-dagh 2375 39'84 27'62 0-52 0-58 0*94 6-85 = 100-10 
 
 5. Bregratten . 26-19 38'30 600 21-11 3-:<0 _ 5-50=100-40 
 Masonite . . 28-27 32-16 33'72 6-13 5-00 = 99'28 
 Sismondine . 24-1 43'2 23'8 7'6 = 987 
 
 Among these analyses Nos. 3 and 5 of chloritoide are the only ones in which the de- 
 gree of oxidation of the iron appears to have been correctly determined ; these agree 
 approximately with the formula (2M 2 O.Si0 2 ).(M 4 3 .Si0 2 ) + 2aq., which, by substitut- 
 ing proto- for sesqui-equivalent metals, maybe reduced to M 2 0.2(M 4 Si0 4 .aq). (Earn- 
 mclsberg's Mineralchemie, p. 864; Dana, ii. 298.) 
 
 CHXiOROBEKTZASiDIDSi. Syn. with CHLOBIDE OF BENZOYL. (See BENZOYL, 
 CHLOBIDE OF, p. 566.) 
 
 CHXiOROBEXTZATCIDX:. See BENZAMIDE (p. 540). 
 
 CHLOROBEXTZECTE. See BENZENE (p. 543). 
 
 CHXiOROBENZXDB. Syn. with TBICHLOEOBENZENE. (See BENZENE, p. 543), 
 
 CHX.OROBXHNTZXX.. C 14 H n C10 2 . (Cahours, Ann. Ch. Phys. [3] xxiii. 350.) 
 Formed by the action of pentachloride of phosphorus on benzilic acid : the product 
 is distilled, and the portion which comes over above 250 C. washed, dried, and rec- 
 tified. It is a colourless, strongly-smelling oil, heavier than water; boils at about 270. 
 By exposure to moist air, or by the action of hot strong potash, it is quickly decom- 
 posed into chloride and benzilate. With ammonia and pheuylamine, it yields crystal- 
 line products. F. T. C. 
 
 CHXiOROBXHNTZOXC ACXD. See BENZOIC ACID. 
 
 CHLOIiOBETJZOIi. Syn. with CHLOBIDE OF BENZYLENE. (See BENZYLENE, 
 CHLOBIDE OF, p. 577.) 
 
 CHX.OROBESTZONXTRXX.X:. See BENZONITBLLE (p. 563). 
 
 CHX.OROBENTZOPUJi-ilJXBE. See BENZOIC Ei'HEBS under BENZOIC ACID (v 
 554). 
 
 CHXtOROBENZOYXi, CHLORIDE OP. See BENZOYL, CHLOBIDE OF (p. 56). 
 
 CHX-OROCAFFEIKTE. C 8 H 9 C1N<0 2 . A product obtained by the incomplete 
 action of chlorine on caffeine suspended in water (p. 708). When purified by three 
 or four crystallisations from water, it forms a light bulky mass. From alcohol it crys- 
 tallises in needles. By the continued action of chlorine, it is rebolved into chloride 
 
 3 N 2 
 
916 CHLOROCAMPHENE CIILOROCODEINE. 
 
 of cyanogen, methylamine, and amalic acid. (Rochleder, Wien Akad. Bcr. 1856 
 ii. 96.) 
 
 CHIiOROCAMPHENE. See CAMPHENE (p. 724). 
 
 CXH.OROCARBO-HYPOSUT.PHURXC ACID. Syn. with TBICHLOBO- 
 
 METHYLsuLPHTTBors ACID. (See METHYL.) 
 
 CHIiOROCARBONIC ACID. Syn. with OXYCHLOBIDE OF CABBON, CHLORIDE 
 OF CARBONYL, or PHOSGENE (p. 774). 
 
 CHIiOROC ARBOSTIC ETHERS. Compounds produced by the action of chlo- 
 ride of carbonyl on the alcohols. They may be regarded as compounds of carbonic 
 anhydride with the chlorides of the alcohol-radicles, or as bodies formed on the mixed 
 type HHO.HC1, in which 2 at. of hydrogen are replaced by carbonyl, CO, and the 
 third by an alcohol-radicle, E : 
 
 ro-rcri ccnci 
 
 CO .1101 = E J Q 
 
 Their formation is represented by the equation : 
 
 , CO")C1 
 E $0 
 
 (COY') Cl 
 
 CHLOBOCABBONATE OF METHYL. C 8 H 3 C10 2 = VTIS rr- (Dumas and 
 
 un ) u 
 
 Peligot, Ann. Ch. Phys. Iviii. 62.) Obtained by introducing wood-spirit into a large 
 flask filled with phosgene-gas : 
 
 CH 3 .H.O + COCP = HC1 + C 2 H 3 C10 2 . 
 
 Colourless, very fluid oil, heavier and more volatile than water ; has a penetrating 
 odour ; burns with a green flame. Gaseous ammonia converts it into carbamate of 
 methyl (urethylane) : 
 
 C0 8 .CH 3 C1 + NH 8 = *J;S? CO) "}o + HCL 
 
 rn ,,jCl . E> n TTri CO")C1 
 
 CO irn + TT t O = LH + J^ f Q 
 
 CHLOBOCABBONATE OF ETHYL. C 3 H 5 C10 2 . (Dumas and Peligot, Ann. Ch. 
 Phys. liv. 226. Cloez, ibid. [3] xvii. 303. Cahours, ibid. [3] xix. 346.) Prepared 
 like the preceding ; also by the mutual action of alcohol and perchloroformic ether, or 
 perchlorinated oxalate of methyl: 
 
 C 3 C1 6 2 + 2C 2 H 6 = C 3 H 5 C10 2 + C 4 H 5 CP0 2 + 2HC1. 
 
 Perchloro- Alcohol. Chlorocar- Trichlorace- 
 
 formate of bonate of tate of 
 
 ethyl. ethyl. ethyl. 
 
 C'CFO 4 + 4C 2 H 6 = 2C 3 H 5 C10 2 + C 6 H'0 4 + 4HC1. 
 
 Perchlor- Alcohol. Chlorocar- Oxalate of 
 
 oxalate of bonate of ethyl. 
 
 methyl. ethyl. 
 
 ' Colourless liquid, very mobile, having a suffocating odour which irritates the eyes 
 Perfectly neutral to test-paper. Specific gravity 1*139 at 15 C. Vapour-density 
 3-823. Boils at 94 C. Very inflammable. Burns with a green flame. Decomposed 
 by hot water, not by cold. Ammonia converts it rapidly into chloride of ammonium 
 and carbamate of ethyl. 
 
 CHLOBOCABBONATE OF AMYL, C 6 H U C10 2 , appears to be formed by the action 
 of phosgene gas on amylic alcohol, but is immediately decomposed by moisture and 
 converted into carbonate of amyl. 
 
 CHI.OROCEROTIC ACID. See CEBOTIC AciD (p. 887). 
 
 CHIiOROCnrXTAMIC ACID. See CINNAMIC Aero. 
 
 CHIiOROCIimroSE. HYDRIDE OF TETBACHLOBOCINNAMYL. (See CINNAMYL.) 
 
 CHljOROCHItORIC ACID. C1 6 13 (?) A compound obtained, according to 
 Millon, (Ann. Ch. Phys. [3] vii. 298) by passing euchlorine (p. 913) through a series 
 of U-tubes cooled by freezing mixtures, the first to C., the others to 18. Hydro- 
 chloric acid then condenses in the first, and chlorochloric acid in the rest, while free 
 chlorine escapes at the end. Chlorochloric acid thus obtained, is a yellowish-red liquid, 
 which boils at 32 C., and is converted into a yellow gas, which decomposes with ex- 
 plosion at 70. With caustic potash, it yields a mixture of 2 at. chlorate and 1 at. 
 chlorite of potassium, whence its composition is inferred : 
 
 C1 6 13 + 3K 8 = 4KC10 8 + 2KC10 2 . 
 
 Chlorochloric acid resembles perchloric oxide, CIO 2 , in most of its properties, and ap- 
 proaches very nearly to it in composition (6C10 2 = C1 6 12 ) ; indeed it is most probably 
 nothing but perchloric oxide mixed with excess of chlorine (see p. 913.) 
 CBIiOROCODEINE. See CODEINE. 
 
CHLOROCOMENIC ACID CHLOROFORM. 917 
 
 CHI.OROCOIVXEiaXC ACID. See Cc-MENIC AciD. 
 C2-ZI,OI10CtriWENE. See CUMENE. 
 
 CHXiOROCUMXxroit. See CUMINOL. 
 CHXOROCir AW AMIDE.) 
 
 CHX,OROCYATII.XDE. [ See CYANAMIDE. 
 
 CHliORODRACOltfESXC ACID. Syn. with CiiLORANisic ACID. (See ANISIC 
 ACID.) 
 
 CHXiORODRACOlVY'Xi. When chlorine is passed into oil of tarragon, a viscid 
 oily liquid is found, called chloride of draconyl, containing 39'9 per cent. C and 3'5H, 
 answering approximately to the formula C 10 H 10 C1 2 O.C1 2 ; and this, when treated with 
 alcoholic potash, yields another viscid oil, chlorodraconyl, containing 42'5 C and 3'4 H ; 
 possibly chloride of draconyl minus the elements of water. (Laurent, Eev. scient. 
 x. 6. Gerh. iii. 355.) 
 
 CHX.ORCEXrANTHXC ACID. See CENANTHic ACID. 
 
 CHLOROFORM. Dichlorinatcd chloride of methyl Pcrchlorideofformyl. CHC1 8 . 
 Soubeiran, Ann. Ch. Phys. [2] xlviii. 131. Soubeiran and Mialh6, Ann. Ch. 
 Pharm. Ixxi. 225. Liebig, ibid. i. 198; Dumas, Ann. Ch. Phys. [2] Ivi. 115. 
 Kegnault, ibid. Ixxi. 577. Grm. vii. 342.) Chloroform was discovered in 1831 by 
 Soubeiran, who called it Ether bichlorique, and independently in 1832 by Liebig, who 
 regarded it as a chloride of carbon : its true constitution was discovered by Dumas in 
 1834. Hutman (J. Chim. med. [3] iv. 476) states, on the authority of Porta's Magia 
 naturalis and Scott's Letters on Demonology and Witchcraft, that it was known in 
 former times, and used as a means of producing insensibility. 
 
 Formation and Preparation. 1. Chloroform is produced, together with mono- 
 chlorinated chloride of methyl, CH 2 C1 2 , when a mixture of chlorine and gaseous chlo- 
 ride of methyl is exposed to the sun's rays. If the two gases be made to pass 
 continuously into a vessel exposed to the sun and connected with a series of cooled 
 receivers, the chloroform, being the least volatile of the products formed, condenses 
 first, and if the current of chlorine be made rather strong, and the receivers not much 
 cooled, the product consists almost wholly of chloroform. 
 
 2. By the action of alkalis on chloral : 
 
 C 2 HC1 8 + KHO = CHC1 3 + CHKO 2 . 
 
 Chloral. Chloro- Formate of 
 
 form. potassium. 
 
 Chloral is distilled with excess of aqueous potash, soda or baryta, or with milk of 
 lime, and the oily distillate is repeatedly agitated with water, separated from the water 
 as completely as possible by decantation, and distilled with 6 or 8 times its volume of 
 strong sulphuric acid in a perfectly dry apparatus. (Liebig.) 
 
 3. By the action of nascent hydrogen upon tetrachloride of carbon. (Greuther, 
 p. 765.) 
 
 4. By boiling trichloracetic acid with aqueous alkalis : 
 
 C 2 HC1 3 2 + K 2 = CHC1 3 + K 2 C0 3 . 
 
 5. By the action of hypochlorites, or of chlorine, in presence of alkalis on various 
 organic substances, viz. : a. On methylic, ethylic, and amylic alcohols, perhaps also on 
 all alcohols of the series C n H 2n+2 O. With common alcohol and hypochlorite of calcium 
 the principal reaction appears to be : 
 
 C 2 H fi O + SCaCIO = CHCP + Ca 2 C0 3 + 2CaCl + CaHO + H 2 ; 
 
 but other products are likewise formed, and chlorine is set free. b. On acetic acid 
 and acetates ; probably thus : 
 
 C 2 H 4 2 + 3CaC10 = CHCP + Ca 2 C0 3 + CaHO + H 2 0. 
 
 c. On acetone. d. On ethylsulphate or ethyltartrate of calcium. e. On oil of tur- 
 pentine and its isomers, the oils of lemon, bergamot, copaiba, &c. 
 
 The most economical method of preparing chloroform, and that which is always 
 adopted on the manufacturing scale, is the distillation of alcohol with chloride of 
 lime. The proportions used are about 6 pts. chloride of lime diffused through 30 pts. 
 water, and 1 pt. alcohol of 33 Beaume. The addition of slaked lime is also advan- 
 tageous, as it absorbs the chlorine, which would otherwise be set free, and thereby 
 diminishes the quantity of secondary products. The following mode of preparation on 
 the large scale is given by Kessler (J. Pharm. [3] xiii. 162). 
 
 The apparatus consists of a large leaden cylinder, the sides of which are soldered 
 with lead. Through the middle of the upper end passes a vertical rod, provided 
 at the bottom with fans, and at the top with a curved handle, its lower extremity 
 turning on a pivot in the base of the cylinder. By this arrangement, the mixture 
 
 3 N 3 
 
918 CHLOROFORM. 
 
 may be stirred up during the operation, and the heat thereby equally diffused. In 
 the upper end of the cylinder there is also a wider aperture, which can be closed at 
 pleasure, and through which the materials- are introduced ; through a third aperture is 
 inserted the delivery-tube by which the chloroform vapour is conveyed to the con- 
 densing apparatus. Opposite to this tube there passes, through the upper base of the 
 cylinder, a leaden tube, widened above like a funnel, and reaching just below the 
 surface of the liquid. Into this funnel-tube, at some distance below the funnel, is in- 
 serted a steam-pipe, serving to convey steam from a boiler to the inside of the funnel- 
 tube ; and above the point of insertion of the steam-pipe, the funnel-tube is furnished 
 with a cock, which, when open, allows the steam to pass upwards to the funnel-tube, 
 and when shut directs it into the mixture in the cylinder. This cock serves to regu- 
 late the supply of vapour, and thereby regulates the heat. The chloroform vapour 
 passes upwards through a worm-tube, enclosed in a condensing vessel, to a cooled 
 Woulfe's apparatus, the last bottle but one of which is half filled with alcohol, and the 
 last with cotton saturated with alcohol. A close-shutting wooden cask may be used 
 instead of the leaden cylinder. 40 kilogrammes (88 '8 Ibs.) of the strongest chloride 
 of lime are introduced into the cylinder by means of a four-cornered wooden funnel 
 adapted to its widest aperture, and provided, near its lower extremity, with two hori- 
 zontal rollers pressing against each other, as in a rolling-mill ; these, when turned 
 by their handles, serve to drive the chloride of lime quickly into the cylinder. 4 kilo- 
 grammes (8'8 Ibs.) of slaked lime are next introduced in the same manner, and then a 
 hectolitre of water (22 gallons) at a temperature of 80 to 90 C., is poured in. The 
 apparatus is now thoroughly luted, and the contents are well mixed by turning the 
 fans. 4 kilogrammes of commercial alcohol are then poured in, together with the 
 residues of former operations. If the distillation of the chloroform does not imme- 
 diately begin, steam is admitted from the boiler, and stopped as soon as the distillation 
 is fairly set up. If the evolution of vapour becomes too rapid, cold water is poured in 
 through the funnel-tube. When the reaction is complete, steam is again admitted 
 into the cylinder, and the contents, which are now heated to 100, frequently stirred. 
 After 3 litres (5' 
 form or alcohol. 
 
 the liquid portion drawn off, and used in the next operati 
 two "Woulfe's bottles likewise serves for the following preparations, and the process 
 may be repeated three or four times in a day. 1 kilogramme of chloride of lime yields 
 from 60 to 80 grammes of pure chloroform. 
 
 According to Simerling (Arch. Pharm. [2] liii. 23), the largest quantity of chloro- 
 form, in proportion to the alcohol used, is obtained from a mixture of 8 pts. chloride 
 of lime, 1 pt. quicklime, 1 pt. alcohol, and 40 pts. water; the rectified chloroform thus 
 produced, amounts to nearly one-third of the alcohol consumed (8 gnn. chloroform 
 from 25 grm. alcohol). 
 
 The use of acetone for the preparation of chloroform is not advantageous, because 
 the price of it is high, and the product does not exceed one-third of the acetone used. 
 This proportion was obtained by first distilling 30 grm. acetone with 150 grm. chloride 
 of lime mixed with water, and rectifying the watery distillate with 40 grm. chloride of 
 lime. Chloroform obtained from wood-spirit has an empyretimatic odour, and always 
 blackens when agitated with sulphuric acid. The largest product was 6 grm. chloro- 
 form from 50 grm. wood-spirit. 
 
 For other methods see Ann. Ch. Pharm. xix. 210. Chnelin's Handbook, vii. 344. 
 
 Chloroform may be contaminated with alcohol, ether, and empyreumatic oils. Ac- 
 cording to Soubeiran, pure chloroform sinks in a mixture of equal parts of oil of vitriol 
 and water. According to Kessler, chloroform containing alcohol diminishes in volume 
 on the application of this test. The presence of alcohol causes opalescence when the 
 chloroform is mixed with water, whereas pure chloroform remains clear (Mialhe, 
 J. Chim. rned. [3] iv. 279). Chloroform containing alcohol acquires a green colour 
 when mixed with chromic acid or with sulphuric acid and acid chromate of potassium ; 
 pure chloroform produces no green colour (Cottell, J. Pharm. [3] xiii. 359). Chlo- 
 roform prepared from wood-spirit is much less pure than that obtained from alcohol. 
 The former is specifically lighter than the latter, has a repulsive empyreumatic odour, 
 and produces unpleasant sensations when inhaled. It is contaminated with about 
 6 per cent, of an empyreumatic oil, containing chlorine, burning with a smoky flame, 
 lighter than water, and boiling between 85 and 133 C. This oil cannot be completely 
 separated by simple rectification, but is nearly, but not quite, destroyed by distillation 
 with sulphuric acid. A similar oil, but in smaller quantity, is likewise obtained in the pre- 
 paration of chloroform from alcohol ; 20 kilogrammes of chloroform from alcohol yielded, 
 when rectified over the water-bath, only 40 grm. of residue consisting of this oil ; it is 
 heavier than water, has an odour different from that of the oil obtained from wood-spirit, 
 and its boiling point varies from 68 to 117 C. (Soubeiran and Mialhe). According 
 
CHLOROFORM. 
 
 919 
 
 to Gregory (Proc. Roy. Soc. Edinb. 1850, p. 391), impure chloroform may be recog- 
 nised by the disagreeable odour which it leaves, after evaporation, on a cloth which 
 has been moistened with it, and by the yellow or brown colour which it imparts to 
 pure oil of vitriol when agitated therewith. Pure chloroform placed upon oil of vitriol 
 produces a contact-surface convex downwards ; impure chloroform gives a plane con- 
 tact-surface. According to Koussin (J. Pharm. [3] xxxiv. 206), the purity of chlo- 
 roform may be tested by means of dinitrosulphide of iron, Fe 6 H 2 S 5 N 4 8 (a salt obtained 
 by the action of ferric chloride or sulphate on a mixture of sulphide of ammonium and 
 nitrite of potassium). Pure chloroform shaken up with this salt, remains colourless ; 
 but if it contains alcohol, ether, or wood-spirit, it acquires a dark colour. To purify 
 chloroform, Gregory agitates it and leaves it in contact with oil of vitriol till the latter 
 is no longer coloured by it, then removes the chloroform, and places it in contact with 
 a small quantity of peroxide of manganese, to free it from sulphurous acid. According 
 to Abraham (Pharm. J. Trans, x. 24), chloroform thus purified quickly decomposes, 
 and is afterwards found to contain hydrochloric acid and free chlorine. According to 
 Christison (ibid. x. 253), chloroform keeps well after being once treated with oil of 
 vitriol ; but the continued action of that liquid (especially if contaminated with nitrous 
 acid) exerts a decomposing action upon it. 
 
 Properties. Pure chloroform is a transparent and colourless oil of specific gravity 
 1-491 at 17 C. (Eegnault) ; 1-52523 at (Pierre). It boils at 61 (Eegnault) ; 
 at 63-5 with the barometer at 772'52 mm. (Pierre). In contact with platinum- 
 wire and with the barometer at 27" 7'", it boils in a dry vessel at 60 -8, but in contact 
 with water, at 57'3 (Liebig). Its vapour-density is 4-199, according to Dumas; 
 
 4-230 according to Kegnault. By calculation (2 vol.) it is ^ " x 
 
 0-0693 = 4-141. Chloroform remains liquid and transparent at 16 C. (Pierre), 
 but may be solidified by the cold produced by its own evaporation ; when it is thrown 
 upon a double filter, the rapid evaporation at the edges causes the remaining portion 
 to solidify in white tufts (Soubeiran and Mialhe"). It has a very pleasant, pene- 
 trating odour, a sweet, fiery taste, and its vapour, when inhaled, produces a sweet taste 
 on the palate. The inhalation of a small quantity of the vapour causes excitement 
 similar to that produced by nitrous oxide ; but a larger quantity produces insensibility 
 to pain, in fact, a kind of coma : hence it is extensively used in surgical operations.* 
 According to Kobin (Compt. rend. xxx. 52) and Augendre (ibid. xxxi. 679), chlo- 
 roform preserves meat from putrefaction (200 times its weight, according to Augendre). 
 
 Chloroform dissolves slightly in water, imparting its sweet taste to the liquid. It 
 mixes in all proportions with alcohol, and is partially precipitated therefrom by water. 
 It dissolves rapidly in ether. It is quite insoluble in sulphuric acid. 
 
 It dissolves phosphorus, sulphur, iodine, and iodoform, also many organic bases and 
 their salts. The solubility of several organic bases in chloroform has been determined 
 by Michael Pettenkofer (Jahresber. d. Chem. 1858, p. 363) and A. Schlimpert 
 (ilnd. 1859, p. 405), whose statements however differ widely, as the following table will 
 show: 
 
 Quantities of AlJcalo'ids dissolved by 100 pts. of Chloroform. 
 
 
 Pettenkofer. 
 
 Schlimpert 
 
 
 Pettenkofer. 
 
 Schlimpert. 
 
 Morphine . 
 
 0-57 
 
 1-66 
 
 Veratrine 
 
 58-49 
 
 116 
 
 acetate 
 
 
 
 1-66 
 
 Atropine 
 
 51-69 
 
 33-0 
 
 Narcotine . 
 
 37-17 
 
 
 Strychnine 
 
 20-16 
 
 14-1 
 
 Quinine 
 
 57-47 
 
 iFo 
 
 nitrate 
 
 
 6-6 
 
 sulphate 
 
 __ 
 
 
 
 Caffeine 
 
 
 
 11-1 
 
 hydrochlorate 
 
 
 
 11*1 
 
 Brucine 
 
 5679 
 
 14-0 
 
 Cinchonine 
 
 4-31 
 
 2-5 
 
 Uigitaline 
 
 
 T25 
 
 sulphate 
 
 _ 
 
 3-0 
 
 Aconitine 
 
 
 
 22-0 
 
 Quinidine(?) 
 
 * 
 
 25-3 
 
 Santonine 
 
 
 
 23-0 
 
 Decompositions. 1. Chloroform decomposes when exposed to air and light, with 
 formation of chlorine, hydrochloric acid, and other products ; but when kept under 
 water, it remains unaltered (M arson, Pharm. J. Trans, viii. 69). 2. At a red heat 
 
 * " For the introduction of this valuable remedy we are indebted to Dr. Simpson ; and although ether, 
 benzole, and many other liquids can produce insensibility to pain, chloroform is of all the most powerful 
 as well as the most manageable. Of course great care must be taken to insure its purity, for the oils 
 which accompany it are very deleterious; and in administering it, one person should do nothing but 
 watch the pulse and respiration of the patient and remove the chloroform if necessary. With due pre- 
 caution, chloroform is very safe; and this precaution will prevent its being used in cases where its use 
 is contra-indicated by the disease of the heart, or by marked tendency to apoplexy." (Gregory, Hand' 
 buok of Organic Chemistry, 3rd cd. London, 1852, p. 178.) 
 
 3 N 4 
 
920 CHLOROFORM CHLOROGENIC ACID. 
 
 its vapour appears to be resolved, partly into trichloride of carbon and hydrogen gas, 
 partly into carbon, hydrochloric acid, and chlorine : 
 
 2CHCP = C 2 C1 8 + H 2 
 and: CHC1 3 = C + HC1 + Cl 2 
 
 The liberation of chlorine in this manner is applied to the detection of chloroform 
 in blood. A quantity of blood, not less than an ounce, is introduced, immediately 
 after its separation from the organism, into a flask connected by a cork with a knee- 
 shaped tube somewhat drawn out in the horizontal arm. A strip of paper, moistened 
 with starch-paste and iodide of potassium, is inserted into the end of this tube; the 
 drawn-out part is heated to redness ; and the flask is heated in a water-bath. The 
 vapour of chloroform thereby evolved is decomposed at the red-hot part of the tube, 
 and the liberated chlorine turns the paper blue. This method is said to be capable of 
 detecting 1 pt. of chloroform in 1,000,600 pts. of blood (Ragsky, J. pr. Chem. xlvi. 
 170). According to Duroy (J. Pharm. [3] xx. 401), it is not to be depended on unless 
 the blood betaken from the animal immediately after the inhalation of the chloroform, 
 or immediately after death. Duroy considers it better to pass a stream of cold air 
 through the blood ; then pass the air, together with the chloroform- vapour, through a 
 red-hot tube, and thence into a solution of nitrate of silver, whereupon, if chloroform 
 be present, a precipitate of chloride of silver will be formed. 
 
 3. Chloroform cannot be set on fire in the air, not even with the aid of a wick ; but 
 its vapour passed into the flame of a spirit-lamp, burns with smoke ; a mixture of 
 chloroform and alcohol in equal measures, burns with a very smoky flame and pungent 
 odour, producing hydrochloric acid (Soubeiran, Liebig). It imparts a green colour 
 to the flame of a candle (Liebig). 4. Chloroform repeatedly distilled in a stream of 
 dry chlorine, is resolved into HC1 and C 2 C1 4 (Regnault). 5. Chloroform heated with 
 nitric acid evolves but a small quantity of nitrous fumes (Soubeiran). 6. When 
 kept under sulphuric acid, it gradually gives off vapours of hydrochloric acid. The 
 alcoholic solution of chloroform, mixed with nitrate of silver, does not deposit any chlo- 
 ride of silver, even in the course of a month (Soubeiran). 7. Boiled with potash-ley 
 in a closed tube, it is resolved into formate and chloride of potassium ; but the de- 
 composition is imperfect (Dumas) : 
 
 CHC1 3 + 2K 2 = CHKO 2 + 3KCL 
 
 Chloroform is not decomposed by boiling with aqueous alkalis in an open vessel 
 (Liebig). Alcoholic potash boiled for a long time with chloroform, produces formate 
 of potassium (Regsault). A mixture of chloroform, potash, and alcohol, heated in a 
 sealed tube to 100 C. for a week, yields ethylene-gas and formic acid (Berthelot, 
 Ann. Ch. Phys. [3] liv. 87). 8. Chloroform vapour passed over ignited baryta or 
 lime, yields metallic chloride, carbonate, and charcoal ; if the heat be moderate, these 
 products are not accompanied by any gas ; but at a full red heat, carbonic oxide is 
 produced by the action of the charcoal on the alkaline carbonate (Liebig, Soubeiran). 
 9. Chloroform may be distilled over potassium without decomposition ; but potas- 
 sium heated in its vapour takes fire with explosion, forming chloride of potassium 
 mixed with charcoal (Liebig). It is not decomposed by sodium, even when heated 
 with it to 200 C. in a sealed tube (Heintz). Chloroform is not decomposed by 
 heating with cyanide of potassium, mercury, or silver, even on the addition of alcohol. 
 (Bouchardat.) 
 
 A mixture of chloroform and ammonia-gas is decomposed by a heat approaching to 
 dull redness, yielding chloride and cyanide of ammonium : 
 
 CHCP + 5NH 3 = 3NIPC1 + NH'.CN. 
 
 If the temperature be raised too high, a brown substance is formed, probably para- 
 cyanogen. When a solution of ammonia in abs lute alcohol is heated with chloroform 
 to a temperature between 180 and 190C M formate of ammonium may be produced 
 as well as cyanide ; in many instances also neither of these salts is formed, but only 
 a brown mass, probably consisting for the most part of paracyanogen. (H ei ntz, Pogg. 
 Ann. xcviii. 263.) 
 
 Chloroform and phenylamine do not react at ordinary temperatures; but when equal 
 volumes of the two are heated to 180 190 C. in a sealed tube, hydrochlorate of 
 phenylamine is formed, together with hydrochlorate of formyl-diphenyl-diamine. 
 
 CHC1 3 + 4(N.H 2 .C 6 IP) = 2[(N.H 2 .C 6 H 5 ).HC1] + [N 2 .H.(CH)'"(C 6 H 5 ) 2 ].HC1. 
 (Hofmann, Proc. Eoy. Soc. ix. 229.) 
 
 CHXiOROFORBXYXi - HYPOSUXPHITRIC ACID. Syn. with DlCHLORO- 
 METHYL-suLi'iiruors AC-ID. (Sec METHYL.) 
 
 CHLOROGENIC ACID. Syn. with CAFFETANNIC ACID (p. 709). 
 
CHLOROGENIN CHLOROPERCHLORIC ACID. 92i 
 
 A substance which accompanies rubian precipitated from 
 extract of madder by sub-acetate of lead, and forms a green powder when boiled with 
 sulphuric or hydrochloric acid. 
 
 CHIiOROMEZiAIi. A product of the action of chlorine on hydrate of myricyl 
 (q. v.) Its analysis agrees approximately with the empirical formula C 30 H 45 ' 5 C1 H ' 5 O 
 (Brodie, Ann. Ch. Pharm. Ixxi. 144.) 
 
 CHI.ORO1VEEZ.ANE. See CKONSTEDTITB. 
 
 CHLOROlVIEiiArJILirjrE. See MELANILINE. 
 
 CHZiOROXVKERCTTRATES. Compounds of mercuric chloride with basic metallic 
 chlorides, or with hydrochlorates of organic bases, e. g. Chloromercurates of potassium, 
 KCLHgCl; KC1.2HgCl; KCUHgCl; Chloromercurate of morphine, C 17 H 19 NO :1 .HC1. 
 4HgCl. They are obtained by mixing the aqueous or alcoholic solutions of the com- 
 ponent salts, and are for the most part crystaUisable. 
 
 CKZ.ORQ1VIESITATE OF JVTETHYZ.ENTE. C 5 H'C1 2 2 . A crystalline 
 substance produced by the action of chlorine on methylic alcohol (q. #.) 
 
 C3IZ,OR01IETHYI,ASE. C 2 H 2 C1 2 . An oily liquid produced by the action of 
 potash on acetate of trichloromethyl. It has the composition of dichlorethylenc, 
 (Laurent, Ann. Ch. Phys. Ixiii. 382.) (See ACETATE OF METHYL, p. 23.) 
 
 CHIiORONAPHTHAKTE. See NAPHTHALENE. 
 
 CHZiORONAPHTHAZiZC ACID. See NAPHTHALENE, CHLORINE-DERIVATIVES 
 OF. 
 
 CHZ.OROVTICEZC ACID. This name was given by St. Evre (Ann. Ch. Phys. 
 [3] xxv. 484), to an acid crystallising in microscopic four-sided needles, which he ob- 
 tained by passing chlorine into a solution of benzoate of potassium, containing excess 
 of potash. St. Evre assigned to this acid the formula C G H 5 C10 2 . But from the expe- 
 riments of Pisani, made in Gerhardt's laboratory, it appears that this acid is nothing 
 but chlorobenzoic acid, C 7 H 5 C10 2 . The acid prepared as above was found, after purifica- 
 tion by repeated crystallisation, to be identical in composition and properties with 
 chlorobenzoic acid prepared by the action of pentachloride of phosphorus on salicylic 
 acid, or on salycilate of methyl. E. Kopp likewise obtained nothing but chlorobenzoic 
 acid, by passing chlorine into a solution of benzoic acid in caustic soda. Hence also, 
 it may be inferred that St. Evre's chloroniccamide is identical with chlorobenzamide ; 
 that chloronicene, a volatile liquid obtained by distilling chloroniceic acid with baryta 
 or lime, is the same as chlorobenzene, C 6 H 5 C1 ; and that cMoronicinc, a base obtained 
 by the action of sulphide of ammonium on chloronicine, is identical with chloro- 
 phenyJamine. (Gerh. iii. 980.) 
 
 CHIiOROPAIf. A hydrated ferric silicate, of which there are two varieties, the 
 conchoidal and the earthy. The former has a pistachio-green colour, is translucent on 
 the edges, has a flat conchoidal fracture; specific gravity 2'158 ; hardness 4'5. The 
 latter has a light green colour, verging towards olive-green and brown, is sometimes com- 
 pact, sometimes friable: the compact variety is very soft. The composition of this mineral 
 varies considerably, as the following analyses will show: 1, 2, from Hungary (Bern- 
 hardi and Brandes, Schw. J. xxxv. 29); 3, 4, from the Meenser Steinberg, near 
 Gottingen (Hiller, Jahresber. d. Chem. 1857, p. 671) : 
 
 SiO 2 Fe 4 s A1 4 G 3 Mg 2 Mn 2 H*0 
 
 1. Conchoidal 46 33 1 2 18=1 00 
 
 2. Earthy . 45 32 075 2 20 = 9975 
 
 3. . 71-6 16-3 2-1 1-5 trace 8*3 = 99-8 
 
 4. Conchoidal 397 28-0 37 2'4 trace 26'1 = 99-9 
 
 It is perhaps a mixture in variable proportions of opal with a hydrated ferric silicate, 
 Fe 4 3 .3Si0 2 + 3H 2 0, or ./V-SiO 3 + H 2 O, or (/e 2 H 2 )SiO 4 , the conchoidal variety analysed 
 by Hiller, containing about 41 per cent, of the ferric silicate, the earthy variety, 70 
 per cent. (Jahresber. loc. cit.} 
 
 CHIiOROPAZiIiADATES. Compounds of dichloride of palladium with the more 
 basic metallic chlorides, or with hydrochlorates. They are not much known. 
 
 CHZ.OROPAZ.Z.ADZTES. Compounds of protochloride of palladium with the 
 more basic metallic chlorides, or with hydrochlorates of organic bases ; e. q. chloro- 
 palladito of potassium, KCl.PdCl ; chloropalladite of strychnine, C 2 'H' 22 N 2 2 .HCl.PdCl. 
 
 CHIiOROPAIilVXITIC ACID. See PALMITIC ACID. 
 
 CKI.OROPERCHI.ORIC ACID. C1 6 17 ? A compound said to be produced 
 by exposing chlorous anhydride to sunshine, the containing vessel being at the 
 same time immersed in water of 20 C. It is a reddish brown liquid which is de- 
 composed by heat, but not explosively ; forms extremely dense white fumes in con- 
 tact with moist air, and is decomposed by potash; yields 1 at. chlorite and 2 at. chlorate 
 
922 CHLOROPHJEITE CHLOROPHYLLITE. 
 
 of potassium: C1 6 0" + 3K 2 = 2KC10 2 + 4KC10 4 . (Mi 11 on, Ann. Ch. Phys. [3] 
 vii. 298. It is perhaps hyperchloric oxide, C1 6 18 = 3CP0 6 (p. 907). 
 
 CHLOROPH2EITE, A ferrous silicate, occurring in foliated or granular massive 
 forms, in the Faroe Islands, also in the neighbourhood of Fife and of Newcastle. It has 
 a dark green colour, and subresinous lustre; specific gravity 2*02 ; hardness 1*5 to 2. 
 According to Forchhammer's analysis (Berz. Jahresber. xxiii. 265), it contains 32-85 
 per cent, silica, 21-56 protoxide of iron, 3 - 44 magnesia, and 12-15 water, whence the 
 formula 2(fFe 2 0.fMg 2 0).3Si0 2 + 12H 2 0, which may be represented as an orthosilicate 
 of the form (M 4 H 8 )Si 3 18 + 8H 2 0. 
 
 CHXiOROPHJEHTERlTE. A hydrated ferrous silicate, found in cavities of the 
 amygdaloi'dal porphyry of Weissig in Saxony. It is blackish-green, with dirty apple- 
 green streak; not very hard; of specific gravity 2*684. Analysis gave 59 '4 per cent. 
 SiO 2 , 12-3 Fe 2 O, and 57 H 2 O, besides alumina, magnesia, lime, potash, and soda. 
 (Jenzsch, Chem. Centr. 1856, 76.) 
 
 CHXiOROPHAXfE. A variety of fluorspar, which emits a green light on calcina- 
 tion. 
 
 CHI.OROPHEWESIC ACID. Syn. with Dichlorophenic acid, C 6 H 4 CrO. (See 
 PHENIC ACID.) 
 
 CHIOROPHENXSIC ACID. Syn. with TmcmoEOPHENic Aero. 
 
 CHIiOROPHEiMTTSIC ACXD. Syn. with PENTACKLOBOPHENIC ACTO. 
 
 CHXiOROPHEBnrii. This name was applied by Laurent to a crystalline substance 
 obtained by the action of boiling nitric acid on trichlorophenic acid. It crystallised 
 in yellow scales insoluble in water, soluble in alcohol and ether, and subliming in very 
 brilliant scales. Analysis gave 37'8 per cent. C, 1'88 H, and 54-30 Cl. (Grerh. ii. 28.) 
 
 CHLOROPH05PIIIDE OF NITROGEN. See NITROGEN. 
 
 CHX.OROPHYX.Iu (Berzelius, Ann. Ch. Pharm. xxi. 257, 262; xxvii. 296. 
 Verdeil, Compt. rend, xxiii. 689. Schulze, ibid, xxxiv. 683. Mulder, Ann. Ch. 
 Pharm. lii. 421.) The colouring matter of leaves and the other green parts of plants. 
 It is extracted by digesting green leaves for several days with ether, evaporating the 
 filtered liquid to dryness, treating the residue with boiling alcohol, and adding to the 
 solution a small quantity of milk of lime, which precipitates all the colouring matter, 
 while the alcohol retains a quantity of fat which was mixed with it. The chlorophyll 
 is separated from the lime by means of hydrochloric acid and ether, which dissolves 
 the colouring matter, forming a green stratum at the top of the liquid. By evaporating 
 the ether, the chlorophyll is obtained in the pure state. 
 
 Chlorophyll thus prepared is an earthy powder, of a deep green colour, unalterable 
 in the air, infusible, sustaining a heat of 200 C. without decomposition, but decom- 
 posing at higher temperatures. It is insoluble in water, even at the boiling heat ; 
 easily soluble in alcohol, less in ether. Acids and alkalis dissolve it with green colour : 
 a solution of alum precipitates it. Nascent hydrogen decolorises it like indigo 
 (Mulder). Mulder represents chlorophyll by the formula C 9 H 9 N0 4 , which however 
 cannot be considered as established. According to Verdeil, chlorophyll has a great 
 analogy to the colouring matter of blood, and like that substance, contains a large 
 quantity of iron. According to Morot (Jahresber. d. Chem. 1859, p. 562), chlorophyll 
 is C 18 H 20 N 2 5 , and is always accompanied by a fatty substance, C 8 H )4 O. The latter 
 is produced by the action of atmospheric oxygen on starch, according to the equation ; 
 
 2CH 10 5 .+ O 2 = C 8 H 14 + 4C0 2 + 3H 8 0. 
 
 and chlorophyll results from the simultaneous action of carbonic acid and ammonia on 
 this fat, under the influence of light : 
 
 C 8 H 14 + 2NH 3 + 10C0 2 = C 18 H 20 N 2 8 + O 18 . 
 
 According to Schultze, chlorophyll forms the colouring matter of several green ani- 
 malcules inhabiting ponds and ditches, such as polypes, turbellarias, and infusoria 
 (Hydra viridis, Vortex viridis, Mesostomum viridatum, Derostomum caecum, Stentor 
 polymorphus, Ophrydium versatile, Bursaria vernalis). 
 
 The name Erythrophyll has been given to the red colouring matter of leaves in 
 autumn. It is soluble in water and alcohol; dissolves with brown colour in alkalis, 
 and forms with lead-salts, a precipitate of a fine green colour. 
 
 CHLOROPHYLLITE. An altered form of cordierite, found at Haddarn in Con- 
 necticut, and Unity, New Hampshire. It occurs in trimetric crystals of the same 
 form as the original cordierite, of greyish or brownish-green colour, and pearly lustre ; 
 specific gravity 2782. According to Eammelsberg's analysis, it contains 46-31 per 
 cent, SiO 2 , 25-17 A1 4 O 3 , 10-99 Fe 4 O 3 , 10-91 Mg 2 0, trace of Mn 2 O, 0-58 Ca 2 0, and 670 
 water ( = 100-60), which numbers, if a .small quantity of tho iron bo supposed to exist 
 as protoxide, may be nearly represented l>y the formula 2(M'-'O.M 4 O 3 .2SiO 2 ) + 3aq., or 
 
CHLOROPICRIN CHLOROSPINEL. 923 
 
 2(M 2 m 6 )Si 2 9 + 3 aq., which is that of a hydrated cordierite. (Eammelsberg's Mineral- 
 ckemie, p. 833.) 
 
 CHXkOROPXCRXXT. CCPNO 2 . (Stenhouse, Phil. Mag. [3] xxxiii. 53. Ger- 
 hardt and Cahours, Compt. chim. 1849, pp. 34 and 170.) This compound may be 
 regarded as marsh-gas, CH 4 , in which 1 at. H is replaced by NO 2 , and 3 more by 
 chlorine. It is produced : 1. By the distillation of picric acid, styphnic acid, or chry- 
 sammic acid with chloride of lime and water : hence also when the bodies which 
 yield either of these three acids by treatment with nitric acid are first boiled with 
 nitric acid and then distilled with chloride of lime. To these belong : creosote, salicin, 
 indigo, cumarin, the yellow resin of Botany Bey, liquid storax, benzoin, Peru-balsam, 
 galbanum, gum assafcetida, ammoniacum, purree, aloes, extract of Campeachy wood, 
 log-wood, fustic, red sandal-wood, &c. Lastly, Dammara resin, and the chlorinated 
 resin formed in the decomposition of usnic acid by chlorine, likewise yield chloropicrin, 
 when treated with nitric acid and chloride of time. 2. By treating picric acid with 
 chlorine water or aqua-regia, or a mixture of chlorate of potassium and hydrochloric acid. 
 
 To prepare it, aqueous picric acid is distilled with chloride of lime till, after about a 
 quarter of an hour's boiling, no more heavy oil passes over with the water. Should 
 the residue be still yellow, it must be redistilled with fresh chloride of lime. The oil 
 is separated from the watery distillate, washed with water to which a little carbonate 
 of magnesium has been added, dried by placing it over chloride of calcium, and 
 rectified. 
 
 Chloropicrin is a transparent, colourless, strongly refracting oil, of specific gravity 
 1-6657, boiling at 120 C. Its odour, in the dilute state, is peculiarly aromatic, but in 
 the concentrated state very sharp, and attacks the nose and eyes less persistently, but 
 quite as violently, as volatile chloride of cyanogen and oil of mustard. It is neutral 
 to vegetable colours. It dissolves sparingly in water, very easily in alcohol and ether. 
 
 Chloropicrin sustains without alteration a heat of 150 C. ; but when passed through 
 a red-hot tube, it is completely decomposed, yielding nitric oxide, chlorine, and tri- 
 chloride of carbon. A small piece of potassium gently heated in the oil, causes strong 
 explosion : at ordinary temperatures, it forms in a few days chloride and nitrate of 
 potassium. Chloropicrin is not decomposed by aqueous potash, even after prolonged 
 contact ; but alcoholic potash gradually decomposes it, forming chloride and nitrate of 
 potassium. Aqueous ammonia exerts scarcely any action upon chloropicrin ; but with 
 ammoniacal gas or alcoholic ammonia, it forms chloride and nitrate of ammonium. It 
 is not acted upon by sulphuric, nitric, or hydrochloric acid, even at the boiling heat. 
 
 BROMOPICRIN. CB^NO 2 . (Stenhouse, Phil. Mag. [4] viii. 36.) Obtained, like 
 chloropicrin, by distilling picric acid with solution of hypobromite of calcium (lime- 
 water containing bromine), and purified by washing with carbonate of sodium, agita- 
 tion with mercrury, and digestion (not distillation) with chloride of calcium. It is a 
 colourless liquid, heavier than water, having the acrid odour of chloropicrin. It is in- 
 soluble in water, easily soluble in alcohol and ether. It may be heated to its boiling 
 point (above 100 C.) without decomposition, but is then decomposed, with evolution 
 of brown-red vapours, even in an atmosphere of carbonic anhydride. At a higher 
 temperature, it decomposes with slight explosion. The alcoholic solution is slowly 
 precipitated by nitrate of silver in the cold, immediately when heated. 
 
 CHIiOROPIATISrATES. Compounds of dichloride of platinum with the moro 
 basic metallic chlorides, or with the hydrochlorates of organic bases : e.g. Chloroplati- 
 nate of ammonium, NH'CLPtCP; Chloroplatinate of Strychnine, C^H 22 N 2 2 .HCl.PtCP. 
 (See PLATINUM.) 
 
 CHXiOROPXiATX&XTXZS. Compounds of protochloride of platinum with more 
 basic metallic chlorides: Chloroplatinite of potassium, KCl.PtCl. (See PLATINUM.) 
 
 CHXiORORHOX>ATX2S. Compounds of sesquichloride of rhodium with more 
 basic chlorides, e. g. CMororhodate of ammonium, 2NH 4 C1.B 2 C1 3 . 
 
 CHXiORORUBXCT. See KUBIAN and MADDER. 
 
 CHXiOROSAXiZCZir. See SALICIN. 
 
 CHXiOROSAIiXGENXXT. See SALIGENIN. 
 
 CHXiOROSAXVXXX>E. Syn. with HYDRIDE OF CHLOROSALICYL. (See SALICYL.) 
 
 CHXiOROSPXWEXi. A grass-green spinel from Slatoust in the Ural, of specific 
 gravity 3 '591 3'594. It contains, according to two analyses by H. Hose (Pogg. 
 Ann. i. 620) : 
 
 A1 4 3 Fe 4 s Mg 2 Cu 2 Ca 2 
 
 64-13 8-70 26-77 0-27 0-27 = 100-24 
 
 57-34 14-77 27-49 0-62 = 100-22 
 
 whence the formula Mg 2 0.(Al 4 O 3 ; Fe 4 3 ) or Mg(Al ; Fe) 2 2 . It is distinguished from 
 Ceylonite (p. 843) by the absence of ferrous oxide. 
 
924 CHLOROSTRYCHNINE CHOLESTERIC ACID. 
 
 CHLOROSTRYCHNIWE. See STRYCHNINE. 
 CHLOROSTYRACIl\r. See STYRACIN. 
 
 CHXiOROSTTCCXC ACIB. An acid obtained by the metamorphosis of perchlori- 
 nated succinate of ethyl. (See Succmic ETHERS.) 
 
 CHLOROSUCCIItflMIDE. See SuCCINIMIDE, 
 
 CHLOROTEREBElvrE. See TEREBENE. 
 
 CHLGRO SULPHURIC ACXB. See SULPHTTRYL, CHLORIDE OF. 
 
 CHXiORO VAI.ERISIC ACID. Syn. with TRICHLORO VALERIC Aero. (See VA- 
 LERIC ACID.) 
 
 CHXiOROVAXiEROSXC ACID. Syn. with TETRACHLOROVALERIC ACID. 
 
 CHLOROXALOVINIC ACID. See OXALIC ETHERS. 
 CHLOROXA1VIETHANE. Syn. With PENTACHLORINATED OxAMATE OF ETHYL. 
 
 (See OXAMIC ETHERS.) 
 
 CHliOROXETHlBE. Syn. with CHLOROXALOVINIC ANHYDRIDE. (See OXALIC 
 ETHERS.) 
 
 CHLOROXETHOSE. C 4 C1 6 0. (Malaguti, Ann. Ch. Phys. [3] xvi. 19. Ob- 
 tained by the action of monosulphide of potassium on perchloric ether : 
 
 2K 2 S = 4KC1 + S 2 + C 4 C1 6 0. 
 
 To prepare it, 50 pts. of monosulphide of potassium are heated with 16 pts. of per- 
 chloric ether and 200 pts. of alcohol of 95 per cent. Chloride of potassium is then de- 
 posited ; the liquid assumes a dark colour ; and after a day, the deposit of chloride of 
 potassium becomes covered with crystals of sulphur. On adding water to the liquid, 
 chloroxethose separates in the form of an oil. 
 
 It is a colourless, limpid, oily liquid, having an agreeable odour like that of meadow- 
 sweet, and a saccharine taste. Specific gravity 1-654 at 20 C. Boils at 210 C. with 
 slight decomposition. Insoluble in water, soluble in alcohol and ether. It is altered 
 after some time by exposure to the air. It is not attacked by alkalis or by ordinary 
 nitric acid; but nitric acid of specific gravity 1-5 attacks it strongly when heated. On 
 exposing it to sunshine in an atmosphere of chlorine, crystals of perchloric ether make 
 their appearance after a few days : C 4 C1 6 + Cl 4 = C 4 C1 10 0. It likewise absorbs bro- 
 mine in sunshine, producing perchlorobromic ether. Exposed to the action of chlorine 
 under a layer of water, it yields hydrochloric and trichloracetic acids : 
 
 C 4 C1 6 + Cl 4 + 3H 2 = 4HC1 + 2C 2 HC1 3 2 . 
 
 CHXiOROXYNAPHTHAXiIC ACID. See OxYNAPHTHALIC AciD. 
 
 CHOCHOCA. A name applied by the natives of South America to dried potatoes 
 prepared by exposing the peeled and boiled tubers to the alternate action of frost and 
 sunshine. 
 
 CHODNEFFITE. Syn. with CRYOLITE. 
 
 CHOX.ACROX.. C 8 H 10 N 4 13 = C 8 H 10 (N0 2 ) 4 5 (?) A product of the action of 
 nitric acid upon bile. This action gives rise to both fixed and volatile products. The 
 volatile substances formed are capric, caprylic, valeric, and butyric acid, together with 
 an oily body which, when treated with strong caustic potash, is resolved into nitro- 
 cholic acid and cholacrol, which latter may be separated from the saline solution by 
 decantation. It is an oily neutral body having a strong odour ; dissolves sparingly in 
 water, freely in alcohol and ether ; when heated, it decomposes with slight explosion. 
 (Redtenbacher, Ann. Ch. Pharm. Ivii. 145.) 
 
 CHOXiAXiXC ACIB. C 24 H'0 5 . Syn. with cholic acid, the non-azotised acid 
 obtained by the action of alkalis on tauroeholic and glycocholic acids. (See CHOLIC 
 ACID.) 
 
 CHOIiEIC ACZB. Syn. with TATJROCHOLIC ACID, the sulphuretted acid of bile. 
 
 CHOX.ESTERZC ACIB. C 8 H 10 5 . This acid is produced, together with cho- 
 loi'danic acid, oxalic acid, several volatile acids, and a resinous substance, by the 
 action of nitric acid on cholesterin. Choloi'dic and glycocholic acids treated with 
 nitric acid yield the same products. To prepare it, cholesterin is treated with 
 nitric acid in a retort, the distilled liquid being frequently poured back, whereby a 
 resinous mass is produced, which slowly dissolves after prolonged boiling with excess 
 of nitric acid. The liquid, when sufficiently concentrated in the retort, leaves an acid 
 gummy residue, containing a large quantity of cholesteric acid, mixed with choloi'danic 
 acid and a resinous substance ; and this residue, on cooling, separates into two layers, 
 the upper of which consists' of crystalline choloi'danic arid, while the lower, which is 
 viscid, consists chiefly of cholesteric acid containing a little oxalic acid. On saturat- 
 
CHOLESTERIN. 925 
 
 ing this liquid with ammonia, precipitating by nitrate of silver, and boiling the preci- 
 pitate with water, cholcsterate of silver is deposited in crystalline crusts, which, when 
 decomposed by sulphuretted hydrogen, yield the acid. 
 
 Cholesteric acid is a yellowish gummy solid, resembling tlae gum of the cherry-tree. 
 It is deliquescent; very soluble in water and alcohol; has an acid, bitter, and astrin- 
 gent taste, and is decomposed by distillation, giving off bitter vapours and leaving a 
 considerable quantity of charcoal. 
 
 The formula of the cholcsterates is C 8 H 8 M 2 5 . The alkaline and earthy salts are 
 soluble and uncrystallisable ; the cholesterates of the heavy metals are insoluble. 
 
 CHOLESTERIW. C 26 H 44 0. This substance was first obtained by Conradi, in 
 1775, from human gall-stones, of which it sometimes constitutes nearly the entire sub- 
 stance. It has been found in human bile by Chevreul (Ann. Chim. xcv. 5 ; xcvi. 
 166); in the blood by Lecanu (Ann. Ch. Phys. Ixvii. 54), Boudet (ibid. lii. 336), 
 Denis (J. Chim. med. [2] iv. 161), and by Becquerel and Bodier (Gaz. med. No. 
 xlvii.) ; in the brain (Couerbe, Ann. Ch. Phys. Ivi. 281 ; Fremy, ibid. [3] ii. 486), in 
 yolk of egg (Lecanu, J. Pharm. xv. 1; Gobley, ibid. [3] xii. 12), and in certain 
 morbid products of the animal economy, such as cerebral concretions, scirrhous matter 
 of the mesocolon, hydropic liquid of the abdomen, ovaries, testicles, &c. (Lassaigne 
 Ann. Ch. Phys.ix. 324; O. Henry, J. Chim. med. i. 280 ; Caventou, J. Pharm. xi. 
 462; Lehmann, Lehrb. d. Physiol. Chem. 2 te Aufl. i. 286). The first exact analysis 
 of cholesterin was made by Chevreul, who assigned to it the formula above given. 
 Its metamorphoses have been studied by March and (J. pr. Chem. xvi. 37), 
 Kedtenbacher (Ann. Ch. Pharm. Ivii. 145), Meissner and Schwendler (ibid. lix. 
 107; and J. pr. Chem. xxxix. 247), Zwenger (Ann .Ch. Pharm. Ixvi. 5; Ixix. 347), 
 
 Heintz (Pogg. Ann. 1*. 524), and Berth elot (Ann. Ch. Phys. [3] Ivi. 51). 
 
 Cholesterin is easily prepared by crystallising biliary calculi from boiling alcohol, 
 to which a little potash is added to dissolve any fatty acids that may be present. The 
 cholesterin is then deposited in colourless nacreous laminse. To obtain cholesterin from 
 brain, that substance is treated with ether, the ethereal extract boiled with alcoholic 
 potash, and the liquid left to cool. It then deposits cholesterin mixed with cerebrate 
 and phosphate of potassium, from which the cholesterin may be dissolved out by ether. 
 
 Cholesterin is white, tasteless, inodorous, insoluble in water, sparingly soluble in 
 cold alcohol, but dissolves very easily in boiling alcohol, from which it separates on 
 cooling in beautiful crystalline nacreous laminae, soft to the touch, and melting at 
 137 C. It dissolves also in ether, wood-spirit, oil of turpentine, soap- water, and 
 neutral fats. A solution of cholesterin in a mixture of 2 vols. alcohol and 1 vol. ether 
 deposits by spontaneous evaporation laminated transparent crystals of hydrate of cho- 
 lesterin, C- 6 H I4 + IPO, which give off their water at 100 C. 
 
 Cholesterin resists the action of concentrated alkaline solutions even at the boil- 
 ing heat ; but lime decomposes it at about 250 C., hydrogen being given off and 
 the cholesterin being converted into an amorphous fatty body nearly insoluble in 
 alcohol. 
 
 Cholesterin is attacked by chlorine and bromine, yielding substitution-products ; the 
 Marine compound is C^H^CPO. For the action of nitric acid upon cholesterin, see 
 CHOLESTERIC ACID. 
 
 Cholesterin sublimes without alteration at 200 C., but decomposes at a higher tempe- 
 rature, yielding several oily products and a solid body. When distilled in a retort, it 
 yields a carbonaceous residue and a neutral oily liquid insoluble in potash, from which 
 a second distillation with water separates a volatile oil having the agreeable odour of 
 geraniums. 
 
 When strong sulphuric acid is gradually added to a slightly heated mixture of cho- 
 lesterin and dilute sulphuric acid, the cholesterin becomes soft, acquires a deep red 
 colour, and decomposes, giving off all its oxygen in the form of water, and is changed, 
 without evolution of gas, into three isomeric hydrocarbons, which Zwenger designates 
 as cholesterilin, a, b, and c ; they are insoluble in water, and may be freed from sul- 
 phuric acid by washing with that liquid. These hydrocarbons are easily cry stalli sable, 
 and like cholesterin are remarkable for possessing high melting points, a has an 
 earthy aspect, melts at 240 C., and is nearly insoluble in alcohol, very sparingly so- 
 luble in ether ; b forms shining scales melting at 255, moderately soluble in hot ether ; 
 if kept in the fused state it loses the power of crystallising ; c is resinous without 
 appearance of crystallisation, and melts at 127, it is also so]uble in hot ether. 
 
 With concentrated phosphoric acid, cholesterin forms two compounds, called chol es- 
 ter one, a and j8, isomeric with each other, but differing in physical properties. Cho- 
 lesterone o forms very brilliant rectangular prisms, melting at 68 C., and distilling 
 almost without alteration ; easily soluble in alcohol and ether. The modification 
 forms small silky needles sparingly soluble in ether, nearly insoluble in alcohol. 
 
 The composition of cholesterilin and cholesterone agrees nearly with the formula 
 
926 CHOLESTROPHANE CHOLIC ACID. 
 
 are> therefore, either isomeric or polymeric. Their formation from cho- 
 lesterin is represented by the equation : 
 
 . C 26 H 44 - H 2 = C 26 H 42 . 
 
 This decomposition shows that cholesterin partakes of the nature of an alcohol ; it is, 
 in fact, homologous with cinnamic alcohol, and its formula may be written C 2G H 43 .H.O. 
 Heated with acetic, butyric, benzoic, and stearic acids, it forms compound ethers, with 
 elimination of water ; thus with stearic acid : 
 
 C 18 H 35 ) n C 26 H ) n C 18 H 35 > n ^ -^ 
 H { + H | = C 26 H 43 [+'* 
 
 Stearic Choles- Stearate of 
 
 acid. terin. cholesteryl. 
 
 These ethers are prepared in the same manner as the glycerides, and are purified by 
 boiling the product with eight or ten times its volume of alcohol, which extracts the 
 unaltered cholesterin, and crystallising from boiling ether. 
 
 Benzoate of Cholesteryl, C 38 H 48 2 = C 7 H 5 O.C 26 H 43 .0, crystallises in small shining 
 micaceous laminae, which melt between 125 and 130 C., dissolve with moderate 
 facility in ether, very sparingly in boiling alcohol. The butyratc, C 4 H 7 O.C 2C H 43 .O, is 
 easily fusible, somewhat soluble in hot alcohol. The stearate, C 18 H 35 O.C 2(i H 43 .0, crys- 
 tallises in small shining needles, having a neutral reaction, sparingly soluble in cold 
 ether, nearly insoluble in alcohol even at the boiling heat. The acetate has likewise 
 been formed, but is difficult to purify, being more soluble in alcohol than the preceding 
 compounds. (Berthelot.) 
 
 CHOLESTROPHAWE. C 5 H 6 N 2 3 . The name given by Rochleder to the final 
 product of the action of chlorine on caffeine (q. v.), called also nitrothdne by Stenhouse, 
 and regarded by G-erhardt as dimethylparabanic acid, C 3 (CH 8 ) 2 N 2 3 . It is also ob- 
 tained by the action of nitric acid upon caffeine. It is soluble in alcohol, and crystal- 
 lises in iridescent scales, which sublime at 100 C. Boiled with potash it yields 
 carbonate and oxalate of potassium, and gives off ammonia (according to Rochleder), 
 or rather methylamine. 
 
 CHOLIC ACID. Cholalic Acid* C 24 H 40 5 . This acid was discovered by De- 
 mar9ay in 1838 (Ann. Ch. Phys. [2] Ixvii. 177), further examined by Theyer and 
 Schlosser (Ann. Ch. Pharm. xlviii. 77 ; 1. 235), and finally by Strecker (ibid. Ixv. 
 9 ; Ixvii. 1 ; Ixx. 161, 166). It is produced by the action of alkalis on the acids of 
 bile, viz. glycocholic and taurocholic acids, the decomposition taking place in the manner 
 represented by the equations : 
 
 C 26 H 43 NO a + H 2 = C 24 H 40 5 + C 2 H 5 N0 2 . 
 
 Glycecholic Cholic Glycocine. 
 
 acid. acid. 
 
 C 26 H 45 NS0 7 + H 2Q = C 24 H 40 5 -r C 2 H 7 NS0 3 . 
 
 Taurochloric Cholic Taurine. 
 
 acid. acid. 
 
 Cholic acid does not exist ready formed in normal bile, but is produced from the 
 nitrogenised acids of bile during the putrefaction of that liquid after its removal from 
 the body. Similar changes appear also to take place within the body in certain 
 states of disease ; hence, according to Thudichum, it occurs in gall-stones (p. 588). 
 
 The easiest mode of preparing cholic acid is to boil the resinous acids precipitated 
 by ether from an alcoholic solution of bile (p. 585) with baryta-water in a retort 
 having its neck directed upwards, adding as much hydrate of barium as will dissolve 
 in the boiling liquid, and continuing the ebullition for about twelve hours. The crys- 
 talline mass of hydrate and cholate of barium obtained on cooling, is decomposed by 
 hydrochloric acid, the cholic acid then separating as a glutinous resin, while chloride of 
 barium remains in solution. The cholic acid is suffered to remain in the liquid till it 
 is completely solidified, a few drops of ether being added to accelerate the process, after 
 which it is washed with cold water, dissolved in boiling alcohol or ether, and the solu- 
 tion left to crystallise. Potash may be used in the preparation instead of baryta, but 
 it is less advantageous. 
 
 Cholic acid has a bitter taste, with slight saccharine aftertaste. It crystallises in 
 two different forms, and with different quantities of crystallisation- water, according as 
 it is deposited from alcohol or ether. 
 
 a. 2C-'II 40 5 .5H 2 0. This hydrate is deposited from boiling alcohol. It forms 
 tetrahedral or more rarely octahedral crystals, belonging to the dimetric system. 
 
 Observed combinations . ooP and P . ooPoo . Katio of principal to secondary axis 
 
 * Cholic acid is the name originally proposed by Demarcay. Strecker afterwards altered it to cho- 
 lalic acid, reserving the term cholic acid for the nitr genous bile-acid which yields this acid, together 
 with glycot-ine, by decomposition ; but it is m ,re systematic to call this nitrogenised acid glycocholic 
 acid, and retain Demarcay s uame for the non-azotised acid. 
 
CHOLIC ACID CIIOLOCHROME. 927 
 
 = 07946 ; P : P, in the terminal edges = 116 114'; in the lateral edges = 96 40'. 
 The crystals are colourless, very brittle, and have a glassy lustre. In a dry atmo- 
 sphere they lose their water of crystallisation, and become opaque. They dissolve in 
 750 pts. of boiling water, in 4000 pts. of cold water, in 20*8 pts. of cold alcohol of 
 70 per cent., and are very soluble in boiling alcohol. The alcoholic solution becomes 
 milky on addition of water, and after a while deposits shining needles. 1 pt. of cho- 
 lic acid (? the f-hydrate), dissolves in 27 pts. of ether. 
 
 b. C 24 H 40 5 .H 8 0. This hydrate is deposited from boiling ether,_in crystals belong- 
 ing to the trimetric system, exhibiting the combination ooP . coPoo . P, but having 
 the aspect of monoclinic crystals, in consequence of the predominance of one half of 
 the P-faces in the same zone. Katio of brachy diagonal, macrodiagonal, and principal 
 axis = 0-6036 : 1 : 0-3752. Inclination of faces. P : P = 71 58'; 119 36', and 
 144 39'; P : ooP = 125 39'; ooP : ooP = 62 15'; ooPoo; ooP = 148 53'. (H. 
 Kopp.) 
 
 The two hydrates above described seem to contain different modifications of cholic 
 acid ; the dimetric variety gives off all its water at 100 C., and may then be heated 
 to 170 without decomposing, whereas the trimetric modification is not easily dehy- 
 drated at 100, and melts, with decomposition, at 150. The two modifications, how- 
 ever, yield the same salts, and are easily converted one into the other. 
 
 Cholic acid heated to 200 C. gives off the elements of 1 at. water, and is converted 
 into choloidic acid: C 24 H 40 5 -H 8 = C 24 H 38 4 , and at 290 it is converted in like 
 manner into dyslysin : C 24 H 40 5 - 2H 2 = C 84 H 36 3 . By distillation, it yields a yel- 
 lowish, very acid oil, with only a very slight carbonaceous residue. The oil is soluble 
 in ether and in alkalis : the alkaline solution precipitates metallic salts. 
 
 Cholic acid dissolves easily in caustic alkalis, also in hot solutions of alkaline car- 
 bonates, expelling the carbonic acid. The CHOLATES, C 24 H 39 M0 5 , have a very bitter 
 taste, sometimes slightly saccharine ; they are soluble in alcohol ; those of the earth- 
 metals and heavy metals are sparingly soluble in water, and may be obtained by 
 precipitation. 
 
 Cholic acid and its salts give with sulphuric acid and sugar the reaction already 
 described as Pettenkofer's test for bile (p. 586). 
 
 C ho late of Ammonium, obtained by passing ammonia- gas into an alcoholic solu- 
 tion of cholic acid and precipitating by ether, forms slender needles, soluble in water. 
 It is decomposed by prolonged exposure to the air, with loss of ammonia, more quickly 
 when boiled with water. 
 
 Choi ate of Barium, C 24 H 39 Ba0 5 , is obtained by dissolving the acid in baryta- 
 water, precipitating the excess of baryta by carbonic acid, and concentrating the fil- 
 trate, as a crystalline pellicle mammellated on the surface, silky in the interior. It 
 dissolves in 30 pts. of cold, 23 pts. boiling water, and in a smaller quantity of alcohol. 
 The solutions are decomposed by a continued stream of carbonic acid. A concentrated 
 solution of cholate of potassium yields a white flaky precipitate with chloride of 
 barium. 
 
 C ho late of Calcium, is precipitated in thick clots, which crystallise from ether. 
 The copper-salt is a bluish- white precipitate. The lead-salt is white, sparingly so- 
 luble in water, soluble in alcohol and acetic acid. The manganese-salt is a semi- 
 crystalline flocculent precipitate. The mercury-salts are white precipitates, which 
 dissolve slowly by ebullition. 
 
 Cholate of Potassium, precipitated by ether from its alcoholic solution, or ob- 
 tained by spontaneous evaporation, forms slender needles. From its aqueous solution 
 it is precipitated by strong potash. Cholate of sodium resembles the potassium- 
 salt. 
 
 Cholate of Silver is obtained as a white precipitate, which partly dissolves on 
 boiling, and crystallises as the solution cools. It blackens slightly at 100 C., dissolves 
 easily in alcohol. 
 
 CHOXiOCHROX&B. The general name for the colouring matters of bile ; it in- 
 cludes the ordinary brown bile-pigment called cholophsein or biliphsein ; a green 
 substance, cholochloinor biliverdin, produced by oxidation of cholophaein; and 
 cholofulvin or bilifulvin, a yellow substance found in thickened ox-bile. These 
 substances were first examined by Berzelius (Lehrb. d. Chem. ix. 281), afterwards 
 by Simon, Plattner, Schmid, Scherer and Heintz (G-erh. Traite, iv. 532), and 
 Thudichum (British Medical Journal, July 14th, 1860). 
 
 Cholophain, or the brown pigment, is contained in bile and in the intestinal canal, 
 and is the substance to which excrements owe their colour. In certain states of disease 
 it occurs in the blood, the serous fluids, the urine, and other liquids of the organism, 
 and is the cause of the yellow colour of the skin and the cornea in jaundice. It is 
 
928 CHOLOCHROME CHOLOCHROMIC ACID. 
 
 most conveniently prepared from gall-stones, of which it sometimes forms the chief 
 part, by exhausting them with alcohol, ether, and boiling water ; washing the residue 
 with hydrochloric acid, then with water ; dissolving it in a weak solution of carbonate 
 of sodium ; and precipitating by an acid. As the cholophsein is very apt to pass into 
 the green pigment by oxidation, it is best to perform all these operations in an at- 
 mosphere of hydrogen (Heintz). From human gall-stones cholophsein may also be 
 extracted by benzene or by chloroform. ( Th u d i c h u m. ) 
 
 Cholophsein recently precipitated is a brown amorphous substance, becoming darker 
 when dry. It is infusible, insoluble in boiling water ; soluble in boiling alcohol, the 
 solution gradually turning green by contact with the air. Hydrochloric acid dissolves 
 it in small quantity, acquiring a blue colour. On adding excess of ammonia, the liquid 
 immediately acquires a greenish-yellow colour, which is changed to red by nitric acid. 
 
 Cholophsein contains, according to Heintz's analysis, 60'9 per cent, carbon, 6'05 
 hydrogen, and 9'1 oxygen, whence maybe deduced the empirical formula, C lb H )8 N 2 4 ' 5 
 (61-9 C, 58 H, 9-0 N, and 23-2 0). 
 
 Caustic alkalis and alkaline carbonates dissolve cholophsein with brownish-yellow 
 colour : the ammoniacal solution yields a brown flaky precipitate with chloride of 
 barium or chloride of calcium. A solution of cholophsein in very dilute alcoholic 
 potash assumes a green colour on addition of hydrochloric acid ; and if nitric acid be 
 then added drop by drop, a fine blue colour is produced, which lasts a long time. 
 
 Cholochlo'in or Siliverdin. This green pigment is produced by the oxidation of 
 cholophsein. An alkaline solution of the latter gradually oxidises by exposure to the 
 air, and, if then treated with acids, yields a green precipitate. Cholochlo'in exists 
 ready formed in ox-bile, and is abundant in that of birds, fishes, and amphibia. 
 
 Thudichum obtains the green pigment by allowing bile to stand in well-closed 
 bottles for two years, whereupon a putrefactive decomposition ensues (p. 587), and 
 cholochrome is precipitated, together with cholic acid and other substances. The pre- 
 cipitate, after decantation of the liquid, is put into a calico-bag and washed with water 
 as long as the liquid will pass through ; then boiled with alcohol and washed on a 
 filter with large quantities of that liquid, which removes cholic acid and its salts, also 
 fats and fatty acids. The colouring matter then remains, mixed with mucus, from 
 which it may be freed by solution in carbonate of sodium. The alkaline solution, 
 treated with hydrochloric acid, throws down a substance of a fine green colour, which 
 however is probably still somewhat impure. 
 
 Cholochlo'in is destitute of taste and odour. It does not melt when heated, but 
 decomposes at a high temperature, leaving a large quantity of carbon. It is insoluble 
 in cold, slightly soluble in boiling water ; easily soluble in alkalis, also in alcohol. 
 
 According to Heintz, cholochlom contains 60-04 per cent. C, 5'84 H, 8-53 N, and 
 25-59 O, whence is deduced the empirical formula C 8 H 9 N0 2 ' 5 , requiring 60-38 C, 5-66 H, 
 8-80 N, and 25'16 O. Cholochlom forms with baryta a green amorphous compound, 
 containing 2 7 '3 per cent, baryta. 
 
 The formulse of cholophsein and cholochlom, as deduced from their analyses, are 
 very uncertain. Thudichum found 60 to 62 per cent, carbon in cholophsein from gall- 
 stones, and as much as 66 per cent, in that prepared from bile. Probably both 
 modifications contain the same number of carbon-atoms, the green compound contain- 
 ing more oxygen than the brown : thus cholophsein = C 8 H 9 N0 2 ' 25 , and cholochloin 
 C 9 H 9 N0 2 ' 5 , or possibly C 8 H 9 N0 8 and C 8 H 9 N0 8 . 
 
 CHOZiOCHROZVXZC ACID. When nitric acid containing nitrous acid, is added 
 to a dilute solution of cholochrome (either brown or green) in an aqueous alkali, the 
 colour of the liquid changes to green, blue, violet, red, and finally to yellow. These 
 changes of colour are connected with the formation of a non-azotised acid, which, ac- 
 cording to Thudichum, may be obtained by passing nitrous acid vapours into water in 
 which cholophsein is suspended. Effervescence then takes place, arising from evolution 
 of nitrogen ; the colour of the bile-pigment changes from brown to red ; and on 
 subsequently shaking it up with ether, a red solution is obtained, which on evaporation 
 leaves a pink syrupy residue, consisting of the non-azotised acid, cholochromic acid. 
 It dissolves easily in chloroform, and the solution, when evaporated in an atmosphere 
 of coal-gas, and afterwards left to stand for some days in a flask filled with the same 
 gas, deposits the acid, partly in flat rhombic octahedrons, partly in groups of radiating 
 needles, partly as an amorphous mass. 
 
 Thudichum assigns to this acid the formula C }6 H*0 7 , or C 9 H 8 3 ' 5 . It should perhaps 
 be C 8 H 8 3 , in which case its formation from cholophsein might be represented by the 
 equation : 
 
 the reaction being that of nitrous acid on an amic acid (p. 168). 
 
 Cholochromic acid is nearly insoluble in cold water, but easily soluble in alcohol : 
 
CHOLOIDANIC ACID CHOLONIC ACID. 929 
 
 the solution has an acid reaction, and precipitates metallic salts. The lead-salt has a 
 red, the silver-salt a pink colour. 
 
 ACID. C 16 H 24 7 (?) The residue in the retort obtained in 
 treating choloi'dic acid with nitric acid, separates on cooling into two layers, the upper 
 of which is crystalline, and consists of choloidanic acid. The crystalline crust is 
 drained on a funnel containing pounded glass, and purified by recrystallisation from 
 boiling water. Should the residue in the retort be merely a resinous mass, it must 
 be further subjected to the action of nitric acid, which will finally convert it into the 
 crystalline acid. 
 
 Cholo'idanic acid crystallises in long hair-like prisms, which, after drying on paper, 
 have the aspect of asbestos. It is nearly insoluble in cold water, and but sparingly 
 soluble in boiling water ; easily soluble in alcohol : the solutions are acid. It does 
 not lose weight at 100 C.; but at a higher temperature it blackens and gives off an 
 acrid acid vapour. It dissolves without alteration in hot nitric or hydrochloric acid. 
 
 Cholo'idanic acid requires a large quantity of alkali to saturate it The choloidanates 
 of the alkali and alkaline earth-metals are soluble in water ; the rest are insoluble or 
 sparingly soluble. They are all decomposed by washing with water. 
 
 CHOZ.OZDIC ACID. C 24 H 38 0. This acid was discovered by Demargay, and 
 has been further examined by Theyer and Schlosser and by Strecker (see refe- 
 rences, p. 926). It is produced by the dehydration of cholic acid at 200 C., and, 
 according to the observations of Grorup-Besanez and of Thudichum (p. 587), is one of 
 the products of the putrefaction of bile : hence also it is found in gall-stones. It may 
 be prepared directly from bile by boiling that liquid, dissolved in 12 to 15 pts. water, 
 with excess of hydrochloric acid for three or four hours, and leaving the liquid to cool. 
 Choloidi'c acid then collects at the bottom in a solid mass, which must be several times 
 melted with water to remove the hydrochloric acid, then pulverised, dissolved in a 
 small quantity of alcohol, shaken up with ether to free it from cholesterin and margaric 
 acid, and finally evaporated to dryness over the water-bath. If the action of the hydro- 
 chloric acid be too long continued, dyslysin is obtained instead of choloidic acid 
 (Demargay). Choloidic acid is likewise obtained by digesting bile with oxalic acid. 
 (Theyer and Schlosser.) 
 
 Choloidic acid is a white non-crystalline substance, which melts in boiling water 
 without dissolving to a sensible amount. After drying it requires a heat of more than 
 150 C. to melt it. It is very soluble in alcohol; water renders the solution milky, 
 and separates the acid in the form of a resin ; the solution has an acid reaction. It 
 is sparingly soluble in ether. 
 
 Choloidic acid unites with bases and decomposes carbonates with aid of heat. The 
 chloi'clates of the alkali-metals are soluble in water and alcohol, insoluble in ether ; 
 they have a pure bitter taste without any sweetish after-taste. By evaporation they 
 are obtained in the form of gummy masses. The salts of the earth-metals and heavy 
 metals are insoluble or sparingly soluble in water, insoluble in alcohol, and are ob- 
 tained in the form of plastic precipitates. The barium-salt, C 24 H 37 Ba0 4 .2H 2 (at 
 120 C.) is insoluble in water and amorphous. The silver-salt, C 24 H 37 AgO (at 100 C.), 
 is a bulky white precipitate, which undergoes considerable contraction and coloration 
 by drying. 
 
 Choloidic acid is oxidised by strong nitric acid, yielding a great number of products. 
 If 1 vol. choloidic acid be treated in a tall vessel with 4 or 5 vol. strong nitric acid, the 
 whole distilled to one-fifth, after the first violent action has subsided, cohobating 
 if necessary, and the liquid, when the action has ceased, diluted with twice its bulk 
 of water and again distilled, a distillate is obtained having a very acrid suffocating 
 odour, arising from the presence of a heavy oil, consisting of nitrocholic acid, 
 CH 2 N 4 5 (?), and cholacrol, while on the surface of the watery liquid there floats 
 a light oil, which is a mixture of acetic, valeric, caprylic, and capric acid. The residue 
 in the retort is a yellowish mixture of oxalic, cholesteric, and cholo'idanic acids. 
 (Redtenbacher, Ann. Ch. Pharm. Ivii. 145.) 
 
 CHOl,oriC ACID. C-'H 4I N0 5 . (Strecker, Ann. Ch. Pharm. Ixvii. 1. Mulder, 
 Untersuch. iiber die Galle. Grerh. iv. 722.) This acid, which is homologous with 
 glyco-hyocholic acid (C 27 H"N0 5 ), is produced by the action of strong acids upon 
 glycocholic acid, from which it differs only by the elements of 1 at. water. 
 
 When a solution of glycocholic acid in strong sulphuric or hydrochloric acid is heated, 
 it becomes turbid and yields oily drops, which solidify and become resinous on cooling ; 
 and by treating this resinous product with baryt,vwater, and decomposing the insoluble 
 barium-salt with hydrochloric acid, cholonic acid is separated, and may be obtained in 
 shining needles by crystallisation from alcohol. 
 
 Cholonatc of Sodium, C 26 H<NaN0 5 , is crystallisable. 
 VOL. I. 30 
 
930 CHONDRIN CHONDRODITE. 
 
 In preparing cholonic acid by the action of^hydrochloric on glycocholic acid, another 
 acid is sometimes formed containing 1 at. H 2 less. (Strecker.) 
 
 CHOHTXmxxX. C I6 H 26 N 2 7 . (J. Miiller, Pogg. Ann. xxxviii. 305. F. Simon, 
 J. Chern. med. i. 108. Vogel, J. pr. Chem. xxi. 426. Hopp, ibid. Ivi. 129). 
 A substance resembling gelatin in many of its properties, and long confounded with 
 it : its separate identity was first established by Miiller. 
 
 Chondrin, like gelatin, does not occur ready formed in the organism, but is produced 
 by boiling certain tissues with water. All permanent cartilages in a healthy state yield 
 chondrin when boiled with water ; so does bone-cartilage or ossein before ossification ; 
 but bone-cartilage after ossification yields gelatin by boiling: so likewise do the 
 tendons, skin, calves' feet, hartshorn, isinglass, and fish scales ; also the permanent car- 
 tilages when they become ossified by disease. 
 
 Chondrin may be prepared by boiling the cartilages of the ribs, larynx, or joints 
 with water for about forty-eight hours, evaporating the liquid to a jelly, and treating 
 this residue with ether to free it from fat. The cornea of the eye yields the same 
 substance. 
 
 Chondrin, when dried, is a hard, horny, diaphanous substance, which softens to a 
 jelly in cold water, and dissolves completely in boiling water ; it is insoluble in alcohol 
 and in ether. The aqueous solution, when boiled for a long time, yields a substance 
 perfectly soluble in cold water, but resembling chondrin in all its other reactions. 
 
 Nearly all acids, even organic acids, precipitate chondrin from its aqueous solution. 
 The precipitate formed by hydrochloric, sulphuric, nitric, phosphoric, phosphorous, 
 chloric, or iodic acid, redissolves easily in excess of the acid ; that formed by sul- 
 phurous, pyrophosphoric, hydrofluoric, carbonic, arsenic, acetic, tartaric, oxalic, citric, 
 lactic, or succinic acid does not redissolve in excess of the acid employed. Strong 
 sulphuric acid dissolves chondrin, forming a syrupy liquid, which, when diluted with 
 water and boiled, yields leucine without glycocine (Hopp). Sulphurous acid slowly 
 decomposes chondrin. Nitric acid, by prolonged action, converts it into xantho-proteic 
 add. 
 
 Alum, sulphate of aluminium, acetate and subacetate of lead, sulphate of copper, 
 ferrous and ferric sulphates, ferric chloride, mercurous and mercuric nitrates, produce 
 copious precipitates in a solution of chondrin, soluble for the most part in excess of the 
 reagent. Ferrocyanide of potassium produces no precipitate. The precipitates formed 
 by acetic acid, alum, and sulphate of aluminium dissolve completely on adding a suffi- 
 cient quantity of acetate of potassium (or of sodium) or common salt. The precipitate 
 formed by ferric sulphate redissolves on heating the liquid. Mercuric chloride does 
 not precipitate a solution of chondrin ; sometimes a slight turbidity is produced, owing 
 apparently to the presence of a little gelatin. 
 
 Chondrin is especially distinguished from gelatin by its precipitation by alum, sul- 
 phate of aluminium, acetate of lead, the sulphates of iron and sulphate of copper, and 
 l>y its non-precipitation by mercuric chloride. (See GELATIN.) 
 
 The aqueous solution of chondrin treated with chlorine, yields a precipitate contain- 
 ing C 16 H 25 C1N 4 (?) (Schroder.) 
 
 By dry distillation chondrin yields the same products as gelatin (q. v.) 
 
 Mulder (Ann. Ch. Pharm. xxviii. 328) found in chondrin from human cartilage, 
 49-3 per cent. C, 6-6 H, 14-4 N, and 0*4 sulphur. Schroder also found in chondrin 
 from the cartilages of the cow, 49*3 carbon and 6-6 hydrogen. 
 
 CHONDRODXTE. Hemiprismatic Chrysolite, Maclureite, Humite, Brwite (in 
 part). A silicate of magnesium containing fluorine ; sometimes occurring in small 
 implanted crystals, but more frequently in crystalline grains or masses of somewhat 
 granular structure, imbedded in granular limestone, as at Purgas in Finland, at Aker and 
 Gulsjo in Sweeden, in Sussex County, New Jersey, in Orange County, New York, and 
 other localities. The variety called humite is from Vesuvius, where it occurs in ejected 
 masses of a kind of granite rock, together with olivine, mica, and magnetite. 
 
 The crystals belong to the trimetric system, and are often hemihedral in octahedral 
 planes, producing forms of monoclinic character ; ooP : o>P = 94 26'. They are of 
 three types, in which the axes have the following ratios : 
 
 Macrodiigonal. Brachydiagonal. Principal axis. 
 
 Type 1 1-4678 : 1 : 1-0805 
 
 Type II. . . . . . 1-5727 : 1 : 1-0805 
 
 Type in 1-4154 : 1 : 1-0805 
 
 Compound crystals also occur. Cleavage indistinct. Specific gravity 3-118 to 3-22. 
 Hardness 6 to 6-5. Colour yellow or brown, inclining to red and green, with waxy or 
 glassy lustre ; more or less translucent. It is scarcely fusible before the blowpipe, 
 gives the reactions of fluorine when heated with sulphuric acid, and with fluxes the 
 
CHONDROGEN CHROMATES. 
 
 931 
 
 reactions of iron and silica. Dissolves in hydrochloric acid, with separation of gelatinous 
 silica. 
 
 Analyses. 1. Seybert (Sill. Am. J. v. 336. 2, 3, 4. Kammelsberg (Mineral- 
 chemie, p. 443). 5. Fischer (Sill. Am. J. [2] ix. 85. 6, 7, 8. Kammelsberg (loc. 
 
 cit.} : 
 
 r,-^n -_o/-v Fe 2 O 
 
 ' 2-33 
 3-65 
 2-35 
 6-75 
 5-50 
 2-40 
 
 Ca^O. 
 
 2-30 0*70 
 
 1-67 
 
 1. New Jersey . 
 
 2. yellow 
 
 3. Pargas, yellow 
 
 4. grey . 
 
 5. New Jersey, red 
 
 6. Humite, type I. 
 
 tvpe II. 
 type 1 1 1. 
 
 SiQ2. 
 32-66 
 33-06 
 33 10 
 33-19 
 33-35 
 
 Mg*0. 
 54-00 
 55-46 
 56-61 
 5450 
 53-05 
 CO-08 
 
 33-26 
 36-67 
 
 5792 
 56-83 
 
 F. 
 
 _ HF 4-09 ; H2Q 1-0; K2Q 2'11 
 
 7-60 = 99-77 
 
 869 = 100-75 
 
 9-69 = 104-13 
 
 7 60 = 99-50 
 
 3-47 = 100-75 
 
 5-04 A14Q 3 = 1-06 = 100-38 
 2-61 = 97-78 
 
 These analyses lead to the formula 8Mg 2 0.3Si0 2 = Mg 16 Si 3 M = 2Mg 2 0.3Mg 4 Si0 4 , 
 wherein part of the oxygen is replaced by fluorine ; or the mineral may be represented 
 as made up of the two compounds : 
 
 Mg 16 Si 3 F 28 , or 16MgF.3SiF 4 = A 
 Mg 16 Si 3 14 , or 8Mg 2 O.3Si0 2 = B 
 
 and: 
 
 in various proportions, namely : 
 
 Chondrodrite from Finland and North America = A 4- 125 
 
 Humite from Vesuvius, type I. = A + I8B 
 
 type II. - A + 27B 
 
 type III. = A + 36B 
 
 Chondrodite occurs altered to serpentine at Sparta, New Jersey, with spinel and mica. 
 (Dana, ii. 186.) 
 
 CHONDROGEM 1 . A name applied to the tissues which yield chondrin when 
 boiled with water, or rather to the substance which may be regarded as the basis of 
 these tissues. 
 
 CHON3>ROITES. Concretions occurring in the cavities and channels of the 
 animal body which are lined with mucous membranes, especially in the nose, gullet, 
 tonsils, and bronchiae : they are produced, under abnormal circumstances, from the 
 secretion of these membranes, their nucleus being sometimes a solid body accidentally 
 lodged in these cavities. They contain very variable quantities of water and animal 
 matter, together with 50 80 per cent, of phosphate of calcium, 6 20 per cent, car- 
 bonate of calcium, 8 12 per cent, carbonate of magnesium, and small quantities of 
 soluble salts. (Handw. d. Chem. ii. [2] 1196.) 
 
 CHOWICRITE. A dense non-crystalline mineral from Elba, of specific gravity 
 2'91, hardness 3. Fracture conchoi'dal. White. Translucent at the edges. Melts 
 with tolerable facility to a greyish- white glass, evolving bubbles of gas at the same 
 time ; blue glass with cobalt-solution. Dissolves slowly in borax, yielding a glass 
 slightly coloured by iron. Easily decomposed by concentrated hydrochloric acid, with 
 separation of silica, not in the usual gelatinous state. According to Kobell's analysis, 
 it contains 12'6 lime, 22*5 magnesia, 1*46 ferrous oxide, 17'12 alumina, 35*7 silica, and 
 9*0 water, a composition which may be approximately represented by the formula : 
 9(2M 2 O.Si0 2 ).2(2Al 4 3 .3Si0 2 ) + 12 aq., which by substituting al = f Al, may be reduced 
 to 3M 4 SiO 4 .2aZ 4 SiO 4 + 4 aq. (Rammclsberg* s Mineralchemie, p. 858). Dana regards 
 chonicrite as a variety of pyrosclerite (q. v.) 
 
 CHRIS iviATIW. A viscid translucent resin from Wettin near Halle, where it 
 occurs as a coating on calcspar in a fissure. It has a shining lustre, and varies in 
 colour from yellow to olive-green. Burns with flame and without odour. (Grermar, 
 Deutsche geol. Zeitschr. i. 40.) 
 
 CHRISTIANITE. See PnnxiPSiTE. 
 
 CHROMATES. Chromic acid unites with nearly all bases. The salts are for 
 the most part easily crystallisable and isomorphous with the corresponding sulphates. 
 The chromates of the alkali-metals, and of strontium, calcium, and magnesium, are 
 soluble in water : the others are insoluble, or sparingly soluble. 
 
 With the alkali-metals, chromic acid forms two series of salts, namely, neutral or 
 normal chromates, MCrO 2 , or M*O.Cr 2 3 , which are yellow, and acid chromates, com- 
 monly called bichromates, 2MCr0 2 .Cr 2 3 , or M 2 0.2Cr0 3 , which have an orange-red 
 colour: a hyperacid chromate, or trichromate of potassium, KCrO^C^O 3 , or K 2 0.3Cr 2 3 , 
 is likewise known. These salts are produced, either by direct saturation of the base- 
 with chromic acid, or by igniting chromic oxide with an alkali and a nitrate or other 
 oxidising agent. 
 
 The insoluble chromates are obtained by precipitation. Most of them are basic. 
 Those which contain 3 at. basic metal to 1 at. chromium, may be called orthochro- 
 
 3 Q 2 
 
932 CHROMATES. 
 
 mates, WCrO*, or 3M 2 O.Cr*0, the ordinary neutral chromates MCrO 2 , which differ 
 from them by M 2 0, being metachro mates. 
 
 A solution of an alkaline chromate gives with a salt of barium, lead, or bismuth, a 
 yellow precipitate : with mercurous salts a brick-red, and with se7wr-salts, a red-purple 
 precipitate : all these precipitates are soluble in nitric acid. Chromates boiled with 
 excess of hydrochloric acid, yield a green solution of sesquichloride of chromium. A 
 chromate of alkali-metal boiled with sulphuric acid and a reducing agent, such as sugar, 
 alcohol, or tartaric acid, yields a purple or a green solution of a chromic alum. Cbro- 
 mates heated with sulphuric acid and common salt, give off yellowish-red vapours of 
 oxychlori;le of chromium. The chromates of the less basic metals give off oxygen 
 when ignited, and leave chromic oxide : the acid chromates of the alkali-metals leave 
 a mixture of chromic oxide and neutral chromate. Insoluble chromates fused with 
 nitre, yield chromate of potassium, which may be dissolved out by water. 
 
 Chromates in solution have a bitter metallic taste, and a poisonous action. 
 
 CHROMATES OF AMMONIUM. The neutral salt (NH 4 )Cr0 2 , is obtained by eva- 
 porating a mixture of chromic acid with excess of ammonia, or by decomposing chro- 
 mate of barium with sulphate of ammonium. Hirzel (Zeitschr. f. Pharm. 1852, p. 24), 
 gradually adds oxychloride of chromium to excess of ammonia, and evaporates the 
 solution at 60 C. Chromate of ammonium then crystallises out, and may be purified 
 by recrystallisation. It forms lemon-yellow needles, permanent in the air; has a 
 pungent taste and alkaline reaction. It is very soluble in water. Leaves chromic oxide 
 when ignited. 
 
 Acid salt, 2NH 4 Cr0 2 .Cr 2 3 , or (NH 4 ) 2 0.2Cr 2 O s . Obtained by dividing a solution of 
 chromic acid into two parts ; saturating one with ammonia, then adding the other, and 
 evaporating the whole over sulphuric acid. It forms orange-coloured crystals, perma- 
 nent in the air, soluble in water, and yielding green chromic oxide when ignited. 
 (Eichmond and Abel, Chem. Soc. Qu. J. iv. 199.) 
 
 Darby (ibid. i. 20), by partially saturating chromic acid with ammonia and eva- 
 porating to the crystallising point, obtained a compound of ammonia with chromic 
 anhydride 2NH 3 .Cr 2 3 , which may be regarded as a chromamate of ammonium, 
 
 ) analogoug to su iphamate of ammonium, 
 
 Hyperacid salt, 2NH 4 Cr0 2 .5Cr 2 3 + lOaq., or (NH^-'O.GC^O 3 + 10 aq. Brown-yel- 
 low, very efflorescent salt, obtained in ill-defined crystals by evaporating a solution of 
 chromic acid half neutralised with ammonia. (Rammelsberg, Pogg. Ann. xciv. 
 607.) 
 
 A compound of chromic anhydride and sal-ammoniac, NH l Cl.Cr 2 8 , is obtained by 
 adding oxychloride of chromium to a strong solution of sal-ammoniac, in crystals 
 having the same form and aspect as the corresponding potassium-compound, but much 
 more soluble in water. (Peligot, Ann. Ch. Phys. [2] Hi. 267.) 
 
 CHROMATE OF BARIUM. The neutral chromate, BaCrQ 2 , is prepared by pre- 
 cipitating chromate of potassium with chloride of barium or baryta-water. It is in- 
 soluble in water, but dissolves, with reddish-yellow colour, in nitric, hydrochloric, or 
 excess of chromic acid, and is precipitated from the solution by ammonia. It is de- 
 composed by alkaline carbonates and sulphates, even at ordinary temperatures, and 
 more quickly when heated. It is used as a pigment called yellow ultramarine. 
 
 Acid salt, 2BaCr0 2 .Cr 2 8 , or Ba 2 0.2Cr 2 8 . A concentrated solution of the neutral 
 salt in chromic acid is decomposed by dilution, part of the salt being precipitated, 
 while an acid salt remains in solution, and may be obtained by evaporation in yel- 
 lowish-brown stellate crystals, containing Ba 2 0.2Cr 2 3 + 2 aq., which dissolve slowly in 
 water, with separation of the neutral salt. (Babo, J. pr. Chem. Ix. 60.) 
 
 CHROMATE OF BISMUTH. When a solution of nitrate of bismuth is added to a 
 moderately concentrated solution of acid chromate of potassium, leaving the latter 
 slightly in excess, an egg-yellow, flocculent precipitate is formed, which afterwards 
 becomes dense and crystalline. It consists of 3Bi 2 3 .2Cr 2 3 or 7Bi 2 3 .4Bi'"Cr 3 6 . It 
 is insoluble in water, may be dried without decomposition at 100 to 125 C., but ac- 
 quires a dark green colour when ignited, and retains this colour after cooling. It 
 dissolves in nitric or hydrochloric acid, forming a deep yellow liquid, which becomes 
 turbid on dilution, from precipitation of basic nitrate or chloride of bismuth. If it be 
 treated with a small quantity of acid, a yellow salt remains undissolved, consisting of 
 Bi*0 3 .2Cr'0 or Bi'OUBi-'Cr'O 8 . The latter may also be obtained by precipitating 
 acid chromate of potassium with a slightly acid bismuth-solution (J. Lowe, J. pr. 
 Chem. Ixvii. 288, 463). According to Pearson (ibid. Ixviii. 255), the precipitate 
 formed in the latter case is Bi 2 3 .Cr 2 O s , and is perfectly insoluble in water, so that it 
 may be conveniently used for the estimation of bismuth. 
 
CHROMATES. 933 
 
 CHROMATE OF CADMIUM. A basic salt, 5Cd 2 0.2Cr*O f + 8aq., or 3Cd 2 0.4CdCr0 2 
 + 8aq., is obtained as an orange-yellow precipitate, on mixing a cadmium-salt with 
 neutral chromate of potassium. On adding ammonia, the salt 2NH 4 Cr0 2 .(NH 3 Cd) 2 O 
 + 2aq. is obtained, which crystallises in transparent, bright-yellow, six-sided pyramids, 
 decomposing when exposed to the air or immersed in water. 
 
 CHROMATE OF CALCIUM. The neutral salt CaCr0 2 + aq., is obtained by dis- 
 solving carbonate of calcium in aqueous chromic acid, or as a light yellow precipitate 
 by mixing concentrated solutions of chromate of potassium and chloride of calcium. 
 It is moderately soluble in water, insoluble in alcohol ; gives off its water at 200 C., 
 and is afterwards very sparingly soluble. The anhydrous salt is used as a pigment. 
 The acid-salt obtained by dissolving the neutral salt in aqueous chromic acid and 
 evaporating, forms red deliquescent crystals, containing 2CaCr0 2 .Cr*0 3 + 3aq. 
 
 Chromate of Calcium and Potassium, (KCa)Cr 2 4 + aq., obtained by saturating acid 
 chromate of potassium with hydrate of calcium, forms lemon-yellow, silky crystals. 
 
 C HE o MATE OF CERIUM, CeCrO 2 , is deposited as a yellow powder from a solution 
 of carbonate of cerium in chromic acid. The filtrate yields on evaporation an acid salt 
 in red prisms, soluble in water. 
 
 CHROMATE OF CHROMIUM. The brown oxides of chromium intermediate be- 
 tween the sesquioxide Cr 4 3 , and chromic anhydride, Cr 2 3 , may be regarded as com- 
 pounds of these two in various proportions, that is, as chromates of chromium. (See 
 CHROMIUM, OXIDES OF.) 
 
 CHROMATE OF COBALT Solutions of cobalt-salts form with chromate of potas- 
 sium, a light red-brown precipitate containing, according to Sarzeau and Malaguti 
 (Ann. Ch. Phys. [3] ix. 431), Co 3 Cr0 3 + 2aq., which is the formula of an orthochromate. 
 
 CHROMATES OF COPPER. When impure cupric hydrate is immersed in a strong 
 solution of chromic acid, a brown solution is formed which deposits a brown powder, 
 probably a tetrabasic salt, 4Cu 0.2Cr'-0 3 , or 2Cu 2 0.4CuCr0 2 (Droge, Ann. Ch.Pharm. 
 ci. 89). The solution filtered through asbestos, and evaporated over oil of vitriol, 
 yields, after a while, green crystals, consisting, according to Kopp (ibid. Ivii. 386), of 
 cupric sulphate in which part of the sulphuric acid is replaced by chromic acid (H 2 S0 4 
 by H 2 Cr 2 4 , or S by Cr 2 ). The mother-liquor decanted therefrom, is free from sul- 
 phuric acid, and yields by evaporation, acid cupric chromate, 2Cu 2 Cr0 2 .Cr 2 3 
 + 2 aq., in brown-black, deliquescent crystals, soluble in alcohol and in ammonia. The 
 aqueous solution deposits on boiling a brown insoluble salt. The crystals give off 
 their water at 100 C., and at a red heat the salt is completely decomposed. The 
 tetrabasic salt above mentioned is deposited as a chocolate-brown precipitate, contain- 
 ing 5 at. water, on mixing a boiling solution of neutral chromate of potassium with 
 basic sulphate of copper. (Malaguti and Sarzeau.) 
 
 An ammonio-chromate of copper, 5NH 3 .Cu 2 0.4CuCr0 2 + aq., is obtained in dark green 
 prismatic crystals, by passing ammonia-gas into water in which tetrabasic chromate of 
 copper is suspended, and cooling the liquid below C. It soon gives off its ammonia 
 when exposed to the air : and is resolved by water into insoluble basic chromate of 
 copper, and a basic ammonio-chromate which dissolves in the water with emerald- 
 green colour. The same basic ammonio-chromate is obtained by treating acid cupric 
 chromate with ammonia. 
 
 Chromate of Copper and Potassium, K 2 0.3Cu 2 0.3Cr 2 3 + 3aq., or CuHO.(KCu 2 
 Cr'O -r aq., is obtained by treating recently precipitated cupric hydrate with solution 
 of acid chromate of potassium, or by mixing a solution of cupric sulphate with acid 
 chromate of potassium, and gradually adding caustic potash. The product is a light 
 brown powder, consisting of microscopic, translucent, six-sided tablets, nearly insoluble 
 in water, but dissolving with deep green colour in ammonia or carbonate of ammo- 
 nium. The solution, if saturated while hot, deposits on cooling green prisms having a 
 strong lustre. 
 
 CHROMATE OF G-LUCINUM is a yellow insoluble precipitate. 
 
 CHROMATE OF IRON. Aqueous chromic acid digested with moist ferric hydrate, 
 yields a brown solution, containing Fe 4 3 .4Cr 2 3 . The solution is not rendered turbid 
 either by dilution or by boiling, and yields on evaporation a brown resinous residue, 
 soluble in water and in alcohol. The basic salt is a brown powder, which is resolved 
 by water into ferric oxide and chromic acid. 
 
 CHROMATES OF LEAD. The neutral or metachromate, PbCrO 2 , is found native as 
 Red-lead ore, Crocoisite, or Lehmannitc, in monoclinic prisms, in which the ratio of the 
 orthodiagonal, clinodiagonal, and principal axis is as 1-041 : 1 : 0-96, and the inclina- 
 tion of the principal axis to the clinodiagonal, 77 30'. The predominant faces are 
 generally ooP and -P. Cleavage most distinct parallel to ooP. Specific gravity 
 6-9 to 6-1. Hardness 2*5 to 3. The crystals are translucent and of a yellow colour, 
 
 3 o 3 
 
934 CHROMATES. 
 
 with various shades of bright hyacinth-rod ; streak orange-yellow. Sectile. It occurs ia 
 decomposed gneiss or granite, at Nisehne Ta-rilsk in the Ural, in Brazil, at Retzbanya 
 in Hungary, at Moldawa in the Bannat, and in Luzon, one of the Philippine Isles. 
 
 Neutral chromate of lead is obtained as a light yellow insoluble precipitate, by 
 mixing a dilute solution of a neutral lead-salt with neutral or acid chromate of potas- 
 sium ; concentrated solutions yield an orange-yellow precipitate. It may also be ob- 
 tained by decomposing sulphate or chloride of lead with chromate of potassium. It 
 is insoluble in water, slightly soluble in nitric acid, easily in potash. At a moderate 
 heat, it melts without decomposition to a brown mass, exhibiting a radiated structure 
 when cold, and yielding a dark yellow, slightly hygroscopic powder. At a full red 
 heat, it gives off oxygen, and is reduced to a mixture of basic chromate of lead and 
 chromic oxide. Heated in a stream of hydrogen gas, it gives up 12 per cent, oxygen, 
 and is reduced to a mixture of chromic oxide and metallic lead, which when heated 
 in a stream of oxygen takes up 7 per cent, of that gas. (On the use of ehromate of 
 lead in organic analysis, see pp. 227, 232.) 
 
 Chromate of lead is much used as a pigment, known as chrome-yellow, also 
 lemon-yellow, Leipzig ydlow, Paris yellow, &c. The finer sorts are prepared by preci- 
 pitation, the commoner kinds by decomposing carbonate, chloride, or sulphate of lead 
 (obtained as a by-product in the preparation of alum-mordants), with chromate of 
 potassium. According to Anthon, 100 pts. sulphate of lead require for decomposition 
 25 pts. of red chromate of potassium, and 100 pts. chloride of lead require 27 pts. 
 of red chromate. Chrome-yellow exhibits various shades of red and yellow, according 
 to its mode of preparation : it is often mixed with chalk, gypsum, heavy spar, clay, 
 sulphate of lead, &c. Cologne ydlow is a mixture of chromate and sulphate of lead 
 with sulphate of calcium, obtained by precipitating a mixture of the nitrates of lead 
 and calcium with a mixture of sulphate of sodium and chromate of potassium. It is 
 not altered by exposure to air or light ; sulphuretted hydrogen turns it brown ; proto- 
 chloride of tin and sulphurous acid reduce it ; alkalis turn it orange or red, by forma- 
 tion of basic chromate of lead. It is used as an oil or water-colour, for lacquering, and 
 may be mixed with many other colours without decomposition ; with Prussian blue it 
 forms a green mixture, called chrome-green, or green cinnabar. In calico- 
 printing, chrome-yellow is formed on the fabrics themselves, by first steeping them in 
 a solution of lead-salt, then in chromate of potassium. For dyeing silk and wool it is 
 not so well adapted. 
 
 Basic Chromate of Lead. A dibasic or tetraplumbic chromate, 2Pb 2 O.Cr 2 J = 
 Pb*O.2PbCr0 2 , known in the arts as chrome-red, is produced from the neutral 
 chromate by digesting it with caustic alkalis, or with levigated oxide of lead, or by 
 boiling it in the recently precipitated state with neutral chromate of potassium, or by 
 fusing it with nitre. It is of a deep orange or red colour, according to the mode of 
 prepai-ation. The finest vermilion-red chromate is formed when 1 pt. of chrome-yellow 
 is thrown into 5 pts. of nitre in a state of fusion, and the resulting chromate of 
 potassium, together with the excess of nitrate, dissolved out by water: the basic 
 chromate of lead then remains in the form of a crystalline powder (Liebig and 
 Wohler). An orange pigment may be obtained very economically, by boiling the sul- 
 phate of lead, which is a waste product in making acetate of alumina from alum by 
 means of acetate of lead, with a solution of chromate of potassium. The basic chromate 
 of l^ad, forms a beautiful orange upon cloth, which is even more stable than the yel- 
 low chromate, not being acted upon by either alkalis or acids. One method of dyeing 
 chrome-orange, is to fix the yellow chromate of lead in the calico, by dipping it 
 successively in acetate of lead and acid chromate of potassium, and then washing it. 
 This should be repeated, in order to precipitate a considerable quantity of the chroraate 
 in the calico. A milk of lime is then heated in an open pan ; and when it is at the 
 point of ebullition, the yellow calico is immersed in it, and instantly becomes orange, 
 being deprived of a portion of its chromic acid by the lime, which forms a soluble 
 chromate of calcium. At a lower temperature, lime-water dissolves the chromate of 
 lead entirely, and leaves the cloth white. 
 
 A sesquibasic or hexplumbic chromate, 3Pb 2 O.2Cr 2 3 =. Pb 2 O.4PbCr0 2 , is found 
 native as Melanochro'ite, Phoenicitc, or Ph&nikochroite, at Beresof in the Ural, asso- 
 ciated with crocoisite, vauquelinite, pyromorphite, and galena. It occurs in tabular 
 crystals, apparently belonging to the trimetric system, reticularly interwoven ; cleaving 
 perfectly in one direction ; also massive. Specific gravity 5*75. Hardness 3 to 3'5. It 
 has a resinous or adamantine, glimmering lustre, cochineal or hyacinth-red colour, be- 
 coming lemon-yellow on exposure to the air. Streak brick-red. Subtranslucent or 
 opaque. 
 
 A chromate of lead and copper, of analogous composition, viz. ^^ > 2 0. 4 (Q^ ) 
 called VauqucUnitr, occurs at Beresof, at Pont Gibaud in the Puy de Dome, and 
 
CHROMATES. 935 
 
 with the crocoisite of Brazil, in monoclinic crystals, usually minute and irregularly 
 aggregated ; also reniform or botryoi'dal, and granular ; amorphous. Specific gravity 
 do to 578. Hardness 2'5 to 3. It has a dark green to brown colour, sometimes nearly 
 black, with adamantine or resinous lustre, often faint. Streak, siskin-green or brownish. 
 Faintly translucent or opaque. Fracture uneven. Kather brittle. (Dana, ii. 360.) 
 
 CHROMATE OF LITHIUM, LiCrO 2 , crystallises in orange-yellow, oblique rhombic 
 prisms, easily soluble in water. 
 
 CHROMATE OF MAGNESIUM, 2MgCrO* + 7 aq., obtained by evaporating a solution 
 of magnesia in chromic acid, forms lemon-yellow crystals isomorphous with sulphate 
 of magnesium. Specific gravity = 1'66 at 15 C. 
 
 Chroniate of Magnesium and Ammonium, Mg(NH 4 )Cr 2 4 4- 3aq., is isomorphous with 
 the corresponding sulphate. 
 
 CHROMATES OFMANGAN E SE. A manganic salt, 3(Mn 4 3 .Cr 2 O s ).Cr 4 3 + 6 aq., is 
 precipitated on mixing sesquichloride of manganese with chromate of potassium. 
 (Fairrie, Chem. Soc. Qu. J. iv. 300.) 
 
 A basic manganous chromate, 2Mn 2 O.Cr 2 O s + 2aq. =Mn 2 0.2MnCr0 2 , is obtained as a 
 crystalline precipitate on mixing manganous sulphate with neutral chromate of potas- 
 sium. It is brown, translucent, and dissolves with orange-yellow colour in sulphuric 
 and nitric acids (Waring ton, Ulnstitut, No. 513, p. 366. Keinsch, Pogg. Ann. 
 Iv. 97). According to Fairrie, it contains chromic oxide. 
 
 CHROMATES OF MERCURY. Mercuric metackromate, HgCrO 2 , is obtained 
 by boiling equal parts of chromic anhydride and yellow mercuric oxide in water, 
 and gradually evaporating till the mercuric oxide disappears, and red crystals are 
 formed in its place : the mother-liquor yields an additional quantity by concentration. 
 It forms dark garnet-red rhombic prisms, becoming darker -coloured when heated. 
 They are decomposed by water, even in the cold, and completely when heated, yield- 
 ing free chromic acid and amorphous mercuric orthochromate, Hg-'CrO 3 . They dis- 
 solve readily in hydrochloric acid, and potash added to the solution throws down yellow 
 mercuric oxide, or perhaps the orthochromate. Strong nitric acid converts them, in 
 the cold, into an amorphous yellow compound, a large portion however dissolving; 
 moderately strong nitric acid and dilute sulphuric acid act in the same manner, ex- 
 cepting that a larger quantity of the yellow compound remains undissolved. 
 
 Mercuric orthochromate, Hg s Cr0 3 , or 3Hg 2 O.Cr 2 3 , is obtained as a brick-red pow- 
 der on adding mercuric nitrate to acid chromate of potassium ; or by boiling yellow 
 mercuric oxide with chromate of potassium (Millon). It is also produced, together 
 with a less basic salt, by precipitating the mother-liquor of the metachromate with 
 carbonate of sodium. On boiling the precipitate with soda-ley, an amorphous, yellow, 
 heavy powder is precipitated, which appears to consist of 7Hg 2 0.2Cr 2 3 , or 
 Hg 2 0.4Hg s Cr0 3 . The same salt appears also to be obtained by boiling recently pre- 
 cipitated mercuric oxide with acid chromate of potassium, till it is converted into a 
 brick-red powder, washing this powder repeatedly by decantation, and heating it with 
 moderately strong nitric acid. It dissolves in strong nitric acid only when recently 
 precipitated ; strong sulphuric acid, with aid of heat, converts it into white mercuric 
 sulphate; hydrochloric acid does not dissolve it. (Gout her, Ann. Ch. Pharm. cvi. 
 244.) 
 
 A tetrabasic mercuric chromate, 4Hg 2 O.Cr 2 3 , or 3Hg 2 0.2HgCr0 2 , of dark violet or 
 brown colour, is said to be obtained by boiling red mercuric oxide with chromate of 
 potassium. When equivalent quantities of basic mercuric chromate and solution of 
 cyanide of mercury and potassium are boiled together for some time, oxycyanide of 
 mercury separates first, and afterwards a compound containing KHgCy 2 and HgCrO 2 . 
 (Geuther.) 
 
 Mercurous chromate, Hg 4 O.Cr 2 3 = HhgCrO 2 , is obtained as a brilliant red 
 crystalline powder, by boiling the basic salt next to be described, with a small quantity 
 of dilute nitric acid, or the double salt of cyanide of mercury and chromate of potas- 
 sium with mercurous nitrate. 
 
 Basic mercurous chromate, 2Hg 4 O.Cr 2 3 = Hhg 2 0.2HhgCr0 2 , is obtained as a brick- 
 red powder by precipitating mercurous nitrate with chromate of potassium. Both 
 these salts when heated, give off oxygen and mercury, and leave chromic oxide of a 
 beautiful green colour. 
 
 CHROMATES OF MOLYBDENUM. The neutral salt dissolves in water with yel- 
 low colour, and yields by spontaneous evaporation, white, scaly, needle-shaped crystals. 
 The acid salt dries up to an amorphous brown mass. The solution of either salt mixed 
 with ammonia yields a precipitate of basic chromate of molybdenum. 
 
 CHR/>MATE OF NICKEL. Hydrate and carbonate of nickel dissolve in chromic 
 acid with yellowish-red colour, forming an acid salt (Malaguti and SarzeauX The 
 
 3 o 4 
 
9'36 CHROMATES. 
 
 solution of a neutral nickel-salt boiled with neutral chromate of potassium, yields an 
 amorphous precipitate, consisting of 3NP0.2NiCr0 2 + aq., and having the colour of 
 Spanish tobacco. If this or the soluble salt be covered with ammonia, a heavy yel- 
 low-green crystalline powder, 3NH 3 .NiCrO 2 + f aq. is formed, which is decomposed by 
 air and water. 
 
 CHBOMATES OF POTASSIUM. Three of these salts are known, viz. : 
 
 Neutral chromate, monochromate, or} -^^ p 2O3 ^r^CM 
 
 metachromate of potassium } K O.Cr O , or KCrO* 
 
 Acid or diehromate . ... K 2 0.2Cr*0 8 , or 2KCrO* Cr 2 3 
 
 Hyperacid or trichromate . . . K 2 O.3Cr 2 3 , or KCrO 2 .O 2 8 . 
 
 The neutral and acid salts are important articles of manufacture, being extensively 
 used in dyeing and calico-printing, and for the preparation of chrome-yellow and 
 chrome-red ; also as oxidising agents : the acid aalt is most used, because it contains 
 a larger percentage of chromic acid. 
 
 The chromates of potassium are prepared by igniting chrome-iron ore, a compound 
 of sesquioxide of chromium and protoxide of iron, in contact with alkalis and oxidising 
 agents, and lixiviating the fused mass with water. A yellow solution is thus obtained, 
 from which, by quick evaporation, the neutral salt is thrown down in yellow crystalline 
 granules ; and by rodissolving this granular salt in water, and leaving the solution to 
 evaporate slowly, the salt is obtained in regular crystals. The concentrated solution 
 of the neutral chromate, treated with one of the stronger acids, yields the acid chro- 
 mate ; and by evaporating the solution to the crystallising point, picking- ant the crystals 
 of acid chromate from the nitrate or other potassium-salt formed at the same time, 
 and recrystallising several times, the acid chromate is obtained in large tabular crystals 
 of an orange-red colour 
 
 The process first adopted for the preparation of chromate of potassium, was to cal- 
 cine the ore with nitre; but it may be rendered more economical by substituting 
 carbonate of potassium (pearlash) for a portion of the nitre ; and still more by dis- 
 pensing with the nitre altogether, and effecting the oxidation of the chromic oxide by 
 means of air admitted into the reverberatory furnace in which the calcination takes 
 place. But whether nitre be used or not, the oxidation is still found to be imperfect, 
 because the alkali fuses into a thin liquid, and the chrome-iron ore, being very heavy, 
 sinks to the bottom, and thus remains to a great extent unaltered, especially when the 
 oxidation is effected by contact with the air, an inconvenience which is but imperfectly 
 obviated even by continual stirring. But by adding lime to the mixture, as first pro- 
 posed by Strom eyer, it is rendered less fluid, and a moderate amount of stirring then 
 suffices to keep it well mixed, so that the oxidation takes place with much greater 
 facility. It is found, indeed, that when lime is added, the nitre may be altogether dis- 
 pensed with, and its place supplied by carbonate, sulphate, or chloride of potassium, 
 which are cheaper. Mr. Tilghman has patented a process for the use of felspar as a 
 source of alkali, 4 pts. by weight of that mineral being calcined in a reverberatory 
 furnace, with 4 pts. of lime or an equivalent quantity of chalk, and 1 pt. of chrome- 
 iron ore. Mr. Booth of Philadelphia subjects the chrome-iron ore to a preliminary 
 ignition with coke or other carbonaceous material, whereby the iron is reduced to the 
 metallic state, then removes the iron by means of dilute sulphuric acid, and subjects 
 the chromic oxide thus purified, to calcination with alkali and nitre ; by this means, 
 the portion of oxygen which would be expended in converting the protoxide of iron 
 into sesquioxide, is rendered available for the production of chromic acid. The pro- 
 duction of sulphate of iron incidental to the process tends to defray the expense. 
 
 Jacquelain prepares acid chromate of calcium from chrome-iron ore, and converts 
 that salt into acid chromate of potassium by double decomposition. The chrome-ore, 
 after being ground to very fine powder and sifted, is mixed with chalk in rotating 
 barrels, and the mixture is spread in a layer 1| to 2 inches thick on the hearth of 
 a reverberatory furnace, heated to bright redness for nine or ten hours, and stirred 
 at least every hour. After this treatment, the mixture has a yellowish-green colour, 
 dissolves in hydrochloric acid, and with the exception of a certain quantity of sand, 
 consists essentially of neutral chromate of calcium (CaCrO 2 ) mixed with oxide of iron. 
 This mass is ground to powder by millstones ; the powder is stirred up with hot 
 water, and sulphuric acid is added till a slight acid reaction becomes apparent. The 
 neutral chromate of calcium is thereby converted into acid chromate. The liquid also 
 contains sulphate of iron, which is precipitated in the same vessel by stirring up with 
 chalk, which does not affect the chrome-salt. The precipitate having settled down, 
 the clear solution of acid chromate of calcium containing a little sulphate is run off, 
 and may be used, without further treatment, for preparing by double decomposition, 
 acid chromate of potassiiun, chromate of lead, either neutral or basic, and chromate of 
 
CHROMATES. 937 
 
 einc. To obtain acid chroffiate of potassium, the solution of acid chrornate of calcium 
 is treated with carbonate of potassium, which throws clown carbonate of calcium in a 
 form easy to wash, leaving acid chromate of potassium in solution, which may then be 
 evaporated and crystallised. The chief advantages of this process are that it requires 
 less stirring than the ordinary method, even when lime is used, and that it avoids the 
 loss of alkali, which always ensues (to the amount of 9 or 10 per cent.) when the mix- 
 ture of chrome-iron ore and potassium-salt is raised to a bright red heat. (For further 
 details on the manufacture of alkaline chromates, see Ure's Dictionary of Arts, 
 Manufactures, and Mines, i. 684 ; and Richardson and Watts' Chemical Technology 
 i. [4] 59.) 
 
 a. Neutral Chromate of Potassi um, KCrO 2 . This salt is obtained by neutrali- 
 sing the acid chromate with an alkali, or by igniting chrome-iron ore with excess of al- 
 kali (p. 936). It crystallises in double six-sided pyramids, belonging to the trimetric 
 system, and isomorphous with sulphate of potassium : hence it is capable of crystallising 
 with the latter in all proportions. It has a pale lemon-yellow colour, an alkaline re- 
 action, and a cooling, persistently bitter taste : it is poisonous even in small doses. 
 Specific gravity 2705 (Kopp). 100 pts. of water at 15 C. dissolve 48 pts. of this 
 salt, and in boiling water it dissolves in all proportions. It possesses great colouring 
 power, 1 pt. of it imparting a distinct yellow tint to 400,000 pts. of water, and a deep 
 yellow colour to 20 pts. of nitre when crystallised therewith. It is insoluble in alcohol, 
 and is precipitated by alcohol from its aqueous solution. The solution yields by eva- 
 poration, red crystals of the acid chromate, and the alkaline mother-liquor after- 
 wards deposits yellow crystals of the neutral salt. The neutral chromate acquires a 
 transient red colour when heated, melts at a higher temperature, and solidifies in the 
 crystalline form on cooling. It is not decomposed by simple ignition, but when heated 
 to redness in contact with charcoal, sulphur, sal-ammoniac, and other reducing agents, 
 it forms chromic oxide together with a potassium-salt. It is decomposed by acids, 
 even by carbonic acid, yielding the acid chromate of potassium. Sulphydric acid and 
 sulphide of potassium decompose it, with formation of chromic hydrate ; sulphurous 
 acid forms at first brown oxide of chromium, then a chromic salt. According to 
 Schweizer (J. pr. Chem. xxxix. 267), arsenious acid forms with it a gelatinous 
 mass, which after drying at 100 C. contains 4K 2 0.3Cr<0 3 .3As 2 5 .10H 2 0. 
 
 b. Acid Chromate, K 2 0.2Cr 2 3 = 2KCr0 2 .Cr 2 3 . Bichromate of Potash, Red 
 Chromate of Potash. This salt is obtained by treating the solution of the neutral salt 
 with one of the stronger acids, or by precipitating a solution of acid chromate of 
 calcium with carbonate of potassium (p. 936). It separates by rapid evaporation as 
 an orange-coloured crystalline powder, and by slower evaporation in splendid garnet- 
 red tables or prisms, belonging to the triclinic system. It is permanent in the air, 
 reddens litmus, has a cooling, bitter, and metallic taste. Its powerful oxidising pro- 
 perties cause it to exert a poisonous action on the animal economy, both internally and 
 externally : the workmen engaged in its manufacture suffer greatly from malignant 
 ulcers. It dissolves in 10 pts. of water at 15 C., much more abundantly in boiling 
 water ; it is insoluble in alcohol. It melts at a heat below redness to a transparent 
 red liquid, which by slow cooling yields large fine crystals, having the same form as 
 those obtained from the aqueous solution, but crumbling to powder at lower tempera- 
 tures. At a white heat, it gives off oxygen, leaving neutral chromate mixed with 
 chromic oxide. Heated with charcoal, it is reduced, with slight detonation ; paper or 
 calico saturated with the solution and dried burns like tinder when heated. Paper 
 thus saturated acquires a darker colour by exposure to light, but remains unaltered in 
 the dark : hence it may be used in photography. Heated with strong sulphuric acid 
 it gives off oxygen (about 1 6 per cent, by weight), and yields water and potassio- 
 chromic sulphate (chrome-alum). 
 
 K 2 Cr 4 7 + 4H*SO = 2[(Cr 2 )'"KS 2 8 ] + 4H 2 + 0. 
 
 It is also reduced when heated with sulphur or sal-ammoniac. Sulphydric acid pre- 
 cipitates from its solution a mixture of chromic oxide and sulphur. Sulphurous acid 
 colours it green without forming a precipitate, from formation of chromic sulphate and 
 hyposulphate. A solution of the salt in boiling hydrochloric acid deposits on cooling 
 chromo- chloride of potassium (p. 938). The solution of acid chromate absorbs a con- 
 siderable quantity of nitric oxide, acquiring a dark colour, and depositing after a while 
 brown oxide of chromium. 
 
 A concentrated solution of the acid chromate mixed with strong sulphuric acid, 
 yields a deep red precipitate of chromic acid. 
 
 A double salt, composed of sulphate and acid chromate of potassium,, is obtained by 
 mixing a concentrated solution of the acid chromate with a quantity of sulphuric acid 
 less than sufficient to convert the potassium into acid sulphate. It crystallises on 
 cooling in stellate needles. (Roinsch.) 
 
938 CHROMATES. 
 
 c. Hyperacid Chromate, or Trichromate of Potassium, K 2 0.3Cr 2 0*, or 
 KCrO 2 .Cr 2 3 , separates from a solution of the acid chromate in ordinary nitric acid 
 prepared at 60 C., in dark red nacreous prisms, of specific gravity 3-631, which blacken 
 when exposed to the air, and melt at 145 150 C. (Graham.) 
 
 Chromate of Potassium and Ammonium, K(NH 4 )Cr'-0 4 , crystallises from a 
 concentrated solution of acid chromate of potassium saturated with ammonia, and 
 cooled by a freezing mixture, or evaporated over lime, in crystals apparently isomor- 
 phous with sulphate of potassium : when exposed to the air, it gives off ammonia and 
 turns reddish-yellow. (Johnson, J. pr. Chem. Ixii. 261.) 
 
 Chromate of Potassium with Mercuric Chloride, KCr0 2 .2HgCl, is obtained 
 by mixing the component salts in equivalent proportions, and adding sufficient hydro- 
 chloric acid to redissolvethe precipitate first produced. Small slightly reddish crystals, 
 which form a yellow solution in water. Another salt, 2KCr0 2 .Cr 2 3 .2HgCl, is obtained 
 in red spicular crystals, by mixing acid chromate of potassium and mercuric chloride in 
 equivalent proportions, and leaving the solution to evaporate. (Darby, Chem. Soc. 
 Qu. J. i. 24.) 
 
 Chromate of Potassium with Mercuric Cyanide, 2KCr0 2 .3HgCy. Light 
 yellow laminar crystals, obtained by evaporating a solution of 1 pt. neutral chromate of 
 potassium and 3 pts. cyanide of mercury. (Darby.) 
 
 Chromo-chloride of Potassium, KCl.Cr 2 8 
 
 analogous in composition to the triacid chromate KCr0 2 .Cr 2 3 , is obtained by dissolving 
 together, with aid of heat, 3 pts. acid chromate of potassium, and 4 pts. hydrochloric 
 acid, avoiding evolution of chlorine. It crystallises in flat, red, rectangular prisms, and 
 is decomposed by solution in water. 
 
 CHROMATES OF SILVER. The neutral salt, AgCrO 2 , is obtained as a red pre- 
 tipitate by decomposing neutral chromate of potassium with nitrate of silver, or by boil- 
 ing the acid silver-salt with water, whereby it is partly resolved into chromic acid and 
 the neutral chromate, which then separates in crystals green by transmitted light, and 
 yielding a red powder. A solution of the acid salt in ammonia deposits the neutral 
 salt on evaporation, in dark green metallic crusts. 
 
 Acid Chromate of Silver, 2AgCr0 2 .Cr 2 3 , is obtained by immersing metallic sil- 
 ver in solution of acid chromate of potassium mixed with sulphuric acid, or by precipi- 
 tating the same acidulated solution with a silver-salt. It has the colour of carmine, is 
 partly soluble in water, and crystallises therefrom in triclinic prisms, having a dark 
 brown colour, red by transmitted light, and yielding a red powder. 
 
 Ammo nio-chr ornate of Silver, 2NH 3 .AgCr0 2 , separates from a hot solution of 
 chromate of silver in ammonia, in yellow, square prisms, isomorphous witli the corre- 
 sponding salts of sulphuric and selenic acid : they give off ammonia when exposed to 
 the air. 
 
 CHROMATES OF SODIUM. Two of these salts are known, namely, the neutral 
 chromate,~N&CrO' 2 , and the acid chromate, 2NaCr0 2 .Cr 2 3 . Theyare analogous in all 
 respects to the neutral and acid chromates of potassium, and may be prepared in like 
 manner. The neutral salt, which may also, according to Johnson (J. pr. Chem. Ixii. 
 161), be obtained by saturating a solution of acid chromate of potassium with carbonate 
 of sodium, and leaving it to evaporate at C., crystallises at low temperatures in yellow 
 transparent crystals, containing NaCr0 2 .5aq., isomorphous with Glauber salt: they 
 melt at the heat of the hand, deliquesce rapidly in the air, are easily soluble in water, 
 sparingly in alcohol, and when immersed in alcohol, become opaque from loss of 
 water. The aqueous solution evaporated at temperatures above 30 C., deposits the 
 anhydrous salt. 
 
 Acid chromate of sodium, 2NaCr0 2 .Cr 2 3 , forms thin, hyacinth-red prisms, 
 very soluble in water. 
 
 CHROMATE OF STRONTIUM. Light yellow powder, obtained by precipitation ; 
 soluble in hydrochloric, nitric, and chromic acid ; rather more soluble in water than 
 the barium-salt. 
 
 CHROMATES OF TIN. Stannic chloride forms with chromate of potassium a yel- 
 low precipitate, which becomes brownish-yellow and translucent when dry, and passes 
 into violet stannic chromate when ignited. 
 
 Stannous chromate is precipitated in yellow curdy flocks, when stannous chloride 
 is added with stirring to excess of chromate of potassium. If the contrary course be 
 adopted, a greenish-white precipitate is formed, perhaps consisting of chromic stannate. 
 The salt leaves a violet residue when ignited. 
 
 URANIC CHROMATE. Uranic nitrate forms an oehre-yellow precipitate with 
 neutral chromate of potassium. The yellow rough-tasting solution of uranic carbonate 
 in aqueous chromic acid, yields small fiery- red eryslals. The salt melts at a gentle 
 heat, with partial decomposition. 
 
CHROME ALUM CHROME IRON ORE. 939 
 
 CHROMA TE OF VANADIUM. The brownish-yellow solution of vanadic hydrate 
 in aqueous chromic acid, yields on evaporation, a shining, dark brown, varnish-like 
 mass, which dissolves partially in water, forming a yellow liquid. 
 
 CHBOMATE OF YTTRIUM. Soluble salt, crystallising in small yellow prisms. 
 
 CHROMA TE OF ZINC. Sulphate of zinc, mixed with neutral chromate of potas- 
 sium, forms a yellow precipitate of a basic salt. Malaguti and Sarzeau, by treating 
 carbonate of zinc with pure chromic acid, obtained a yellow crystalline basic salt, con- 
 taining 4Zn 2 O.Cr 2 3 (- 5 aq., or Zn 3 Cr0 3 .ZnHO + 2 aq. By boiling this salt with chromic 
 acid as long as anything dissolves, the same chemists obtained a soluble non-crystalline 
 salt, 2Zn 2 0.3Cr 2 O s , or 4ZnCr0 2 .Cr 2 3 . 
 
 Ammonio-chr ornate of Zinc. The tetrabasic salt repeatedly treated with am- 
 monia, yields yellow cubic crystals, containing 2(ZnCr0 2 .NH 3 ) + 5aq. Soluble chromate 
 of zinc, ZZn*0.8Cr*O", treated with excess of ammonia and then with alcohol, yields a 
 copious precipitate, consisting of microscopic needles containing 5NH 3 .4ZnCr0 2 + 9 aq. 
 (Malaguti and Sarzeau.) 
 
 Chromate of Zinc and Potassium. The precipitate formed by chromate of 
 potassium in sulphate of zinc, if left for sometime under the liquid, changes to an orange- 
 yellow powder, consisting of the double salt. It is sparingly soluble in cold water, but 
 imparts a yellow colour to a large quantity of the liquid ; in boiling water, it dissolves 
 with deep yellow colour, with separation of a lighter coloured basic salt. When ignited, 
 it leaves a dark brown residue, from which water extracts neutral chromate of potassium, 
 leaving a compound of sesquioxide of chromium and oxide of zinc. (Handw. d. Chem. 
 ii. [2] 1246.) 
 
 CHROME AXiTTlVX. This name is applied to the double sulphates of chromium 
 and the alkali-metals, analogous in composition to common alum and isomorphous 
 
 therewith, e.g. potassio-chromic sulphate, K(Cr 2 )"'(S0 4 ) 2 + 12H 2 
 
 12H 2 0. 
 
 CHROME GREE3M. A name applied sometimes to green oxide of chromium, 
 sometimes to the pigment produced by mixing chrome yellow with Prussian blue. 
 (-See CHROMATE OF LEAD, p. 934.) 
 
 CHROIVTE IRON ORB. Chromic Iron, Chromate of Iron, Chromcisenstein, 
 Eisenrhrom, Ferrochromate. This mineral, which is the most abundant ore of chromium, 
 usually occurs massive, with fine granular or compact structure, forming veins or im- 
 bedded masses in serpentine; more rarely in regular octahedrons, with imperfect 
 cleavage parallel to the octahedral faces. Specific gravity 4-32 to 4*57. Hardness 5'5. 
 Colour brownish-black, or iron-black. Streak brown. Lustre submetallic, inclining 
 to waxy. Opaque. Brittle, with conchoidal or uneven fracture. Sometimes magnetic. 
 Before the blowpipe it does not fuse, but becomes more strongly magnetic. With 
 borax or phosphorus-salt it fuses with difficulty, but completely, to a beautiful green 
 globule. 
 
 Chrome iron ore belongs to the spinel group of minerals, whose general formula is 
 
 M 2 O.R 4 S or /-R2V" ( O 2 . The monatomic metal is chiefly iron, but magnesium is 
 
 generally also present in considerable quantity, and in some specimens a small portion 
 of the chromium appears to exist as chromosum. The sesqui-atomic metal E is 
 principally chromium, but it is replaced to a considerable extent by aluminium, 
 si ml sometimes also by iron (ferricum), so that the general formula of the mineral is 
 
 C '**' Al 2 '- ' F ^ 2 ' v ^ 2 ' -^ rom *ke num erous analyses tlyit have been made of it, we se- 
 lect the following as samples of the different varieties : a, from Baltimore, Maryland, 
 by Abich (Pogg. Ann. xxxiii. 335); b, from Volterra, Tuscany, by Bechi (Sill. Am. 
 J. [2] xiv. 62); c, from Texas, Lancaster county, Pennsylvania, by Franke (Earn- 
 mvlsberg's Miner alchemic); d, from the same, by Garrett (Sill. Am. J. [2] xiv. 46) ; 
 e, crystallised, from Baltimore, by Abich (loc. cit.}; /, from Beresow, Siberia, by 
 Moberg (J. pr. Chem. xliii. 119) : 
 
 Cr 4 3 . 
 
 Cr 2 . 
 
 Fe 4 s . 
 
 Fe'O . 
 
 A1 4 3 . 
 
 Mg 2 . 
 
 Ni 2 . 
 
 98-52 10071 100-36 104-32 99*29 100-45 
 
 a 
 
 b 
 
 c 
 
 d 
 
 e 
 
 / 
 
 65-37 
 
 44-23 
 
 55-14 
 
 63-38 
 
 58-25 
 
 59-80 
 
 
 
 
 
 
 
 
 
 1-61 
 
 4-39 
 
 1-10 
 
 0-33 
 
 12-06 
 
 
 
 
 
 __ 
 
 18-04 
 
 35-32 
 
 18-02 
 
 38-66 
 
 20-13 
 
 18-59 
 
 13-97 
 
 20-83 
 
 575 
 
 
 
 11-85 
 
 10-93 
 
 10-04 
 
 
 
 9-39 
 
 
 
 7-45 
 
 674 
 
 
 
 
 
 
 
 2-28 
 
 
 
 
 
940 CHROME-MICA - CHROMIUM. 
 
 Besides the above localities, chrome-iron ore is found in the islands of Unst and Fetlar 
 in the Shetland group, in the Departement du Var in France, in Silesia and Bohemia, 
 at Roraas in Norway, near Kraubat in Syria, abundantly in Asia Minor and the 
 Eastern Urals, and in several parts of North America. It assists in giving the green 
 colour to verd-antique marble. The ore used in this country is obtained chiefly from 
 the Shetland Isles, Norway, and Baltimore, the quantity amounting to 2000 tons an- 
 nually. (Dana, ii. 106; Rammelsberg' s Mincralchemie, p. 172.) 
 
 CHROME-MXCA. This name was given by Breithaupt to an emerald-green 
 mica with nacreous lustre from the Pinzgau. 
 
 CHROME-OCHRE. Native chromic oxide. 
 
 CHROME-RED and CHROME- YEX.I.OW. See CHBOMATES OF LEAD (p. 934). 
 
 CHROMIC ACID. (pp. 931, 952). CHROMXTE. Syn. with CHROME-!RON ORE. 
 
 CHROMXTES. Compounds of sesquioxide of chromium with protoxides (p. 951). 
 
 CHROMIUM. Symbol Or. Atomic weight 26'2. This metal was discovered by 
 Vauquelin in 1797. It is not very abundant, and never occurs in the free state. It 
 is found as sesquioxide (chrome-ochre), as sesquioxide combined with protoxide of iron 
 (chrome-iron ore), as chromate of lead (crocoisite or red lead-spar, p. 934) ; in small 
 quantity in many iron ores, and frequently in meteoric iron ; it is also the colouring 
 principle of many minerals, as the emerald, green serpentine, olivin, &c. 
 
 The most abundant ore of chromium is chrome-iron. This mineral ignited with al- 
 kalis in presence of oxidising agents, yields a chromate of the alkali-metal ; these salts 
 treated with acids and reducing agents yield sesquioxide of chromium ; and from this 
 substance the metal itself, and many of its compounds, may be prepared. 
 
 Metallic chromium is obtained by reduction of the oxides or chlorides, as when ses- 
 quioxide of chromium is mixed with one-third of its weight of lamp-black or sugar- 
 charcoal and exposed in a crucible lined with charcoal to the heat of a blast furnace ; 
 the metal is thereby obtained as a whitish-grey mass, which cannot be melted together 
 into a button. Peligot, by heating the violet sesquichloride of chromium with potas- 
 sium, obtained the metal in the form of a dark grey powder. Fremy, by heating the 
 sesquichloride in a porcelain tube and passing vapour of sodium over it in a current of 
 hydrogen, obtained it in very hard shining crystals. Bunsen, by electrolysing a solu- 
 tion of the sesquioxide, obtained the metal in brittle laminae, having the colour of iron 
 and metallic lustre. According to Berzelius, when sesquichloride of chromium is 
 heated in an atmosphere of hydrogen, there is obtained, besides the protochloride, a 
 shining deposit of metallic chromium. 
 
 Wohler (Ann. Ch. Pharm. cxi. 230) obtains metallic chromium by reducing the 
 sesquichloride with zinc. One pt. of the violet sesquichloride, and 2 pts. of a mixture of 
 the chlorides of potassium and sodium (7 pts. chloride of sodium to 9 pts. chloride of 
 potassium) are closely pressed into an ordinary earthen crucible, 2 pts. of zinc are laid 
 on the mixture, and the whole is covered with a layer of the flux. The crucible is 
 then gradually heated to redness, and the mass is kept in a state of fusion, till a hiss- 
 ing noise is heard, and a zinc-flame is observed on removing the cover for a moment. 
 The crucible is then taken out, gently tapped to cause the metal to collect, and left to 
 cool. A good regulus of zinc is then found at the bottom covered with a green slag. 
 This regulus is well washed with water and digested in dilute nitric acid, which dis- 
 solves the zinc, and leaves the chromium in the form of a grey powder, which must be 
 purified by again heating it with nitric acid and washing. By this method Wohler 
 obtained 6 or 7 grms. of metal from 30 grms. of the chloride, the calculated quantity 
 being 10 grms. Magnesium may be used in the reduction instead of zinc, but it offers 
 no particular advantage. With cadmium as the reducing agent, a violent explosion 
 occurred. 
 
 Chromium obtained by Wohler's process is a light green, glistening, crystalline 
 powder, which, when magnified fifty times, exhibits aggregates of crystals like fir- 
 branches, interspersed with individual crystals of tin-white colour, high lustre, and 
 specific gravity 6'81 according to Wohler, 7'3 according to Bunsen. These crystals, 
 according to Wohler, have the form of a very acute rhombohedron ; but according to 
 Bolley (Chem. Soc. Qu. J. xiii. 334), who examined them with a magnifying power 
 of 85, they are quadratic octahedrons with acuminated summits and bevelled terminal 
 edges, and very frequently united by fours in the form of a cross. This is the third 
 example known of an elementary body crystallising in the dimetric or quadratic 
 system, the others being tin and boron ; as a general rule, ductile metals crystallise 
 in the monometric or regular system ; brittle metals in the hexagonal system. 
 
 Wohler's chromium does not exert the slightest action on the magnetic needle. 
 When heated to redness in the air, it acquires a yellow and blue tarnish like steel, and 
 gradually becomes covered with a thin film of green oxide ; but the oxidation is by no 
 means complete. Thrown into a spirit flame fed with oxygen, it burns with sparkling, 
 
CHROMIUM: BROMIDES CHLORIDES. 941 
 
 but not so brightly as iron. On melting chlorate of potassium it burns with dazzling 
 white light. Melting nitre oxidises it very readily, but without incandescence. In 
 melting carbonate of sodium it remains unaltered. Heated in chlorine gas, it exhibits 
 vivid incandescence. It is but superficially converted into green oxide by ignition in 
 a stream of aqueous vapour free from air. Hydrochloric acid dissolves it readily, with 
 evolution of hydrogen, forming blue chromous chloride. Dilute sulphuric acid does not 
 act upon it at ordinary temperatures, but on applying a gentle heat, a violent action 
 suddenly takes place, and the remaining metal acquires the power of dissolving easily 
 in the most dilute sulphuric acid, even after washing. It is not attacked by nitric 
 acid, either concentrated or dilute. (Wohler.) 
 
 The properties of chromium differ considerably, according to the manner in which 
 it is prepared, the peculiarity doubtless depending chiefly on the state of aggregation. 
 Peligot's chromium oxidised with great facility, taking fire in the air, even at a heat 
 below redness, and being converted into green sesquioxide. It likewise dissolved in 
 dilute sulphuric and hydrochloric acids, and was oxidised by nitric acid. 
 
 The crystals of chromium obtained by Fremy belong, according to Senarmont, to the 
 regular system. They were not attacked by any acid, not even by nitromuriatic acid. 
 
 Chromium may be polished, and then acquires a fine metallic lustre. When pure it 
 is even less fusible than platinum (Deville, Polyt. Centralbl. 1857, p. 605). A frag- 
 ment of it scratches glass ; it is at least as hard as corundum. 
 
 Chromium unites with bromine, chlorine, fluorine, iodine, cyanogen, nitrogen, oxygen, 
 phosphorus, and sulphur, also with aluminium and iron. There are two classes of 
 chromium-compounds, into which the chromium enters as the positive or basic ele- 
 ment, namely, the chromous compounds, in which it is monatomic, e. g, CrCl, Cr 2 0, 
 Cr 2 SO ', &c., and the c hromi c compounds, in which it is sesquiatomic e. g. Cr 2 Cl 3 , Cr 4 3 , 
 Cr 4 (SO 4 ) 3 , &c. It likewise forms an oxide or anhydride, Cr 2 3 , in which it is tri- 
 atomic, and to this there corresponds a class of salts, the chromates, into which the 
 
 PW ) 
 chromium likewise enters as a triatomic radicle, e. g. chromate of lead, p, [ O 2 . 
 
 CHROMIUM, BROMIDES OF. The anhydrous scsquibromide, Cr 2 Br 3 , may be 
 prepared, like the chloride, by passing bromine-vapour over an ignited mixture of 
 chromic oxide with charcoal and starch-paste. Part of the resulting bromide then 
 sublimes beyond the mass of oxide, while another portion remains therein in crystal- 
 line scales, which, however, are easy to separate. It forms black semi-metallic hexa- 
 gonal scales, translucent with olive-green colour, and exhibiting in one direction a 
 faint red dichroism. It forms a yellowish-green powder when triturated, in which 
 form also part of the compound sublimes during the preparation. It is quite insoluble 
 when pure, but dissolves to a green liquid if mixed with protobromide. It is decomposed 
 by alkalis more easily than the chloride. When gently heated in hydrogen gas, it is 
 reduced to the white protobromide, CrBr, which on exposure to the air quickly de- 
 liquesces to green oxybromide. (Wohler, Ann. Ch. Pharm. Ixi. 382.) 
 
 A solution of chromic bromide is obtained by dissolving chromic hydrate in hydro- 
 bromic acid, or by treating chromate of silver with hydrobromic acid and alcohol. 
 The solution yields green crystals, and is easily decomposed by evaporation, with form- 
 ation of oxybromide. 
 
 CHROMIUM, CHIiORIDES OF. Two chlorides of chromium are known in 
 the free state, viz. CrCl and Cr'Cl 3 . A trichloride, CrCl 3 , may also be supposed to 
 exist, combined with chromic anhydride, in chlorochromic anhydride, CrCl 3 .Cr 2 O s . 
 
 PROTOCHLORIDE OF CHROMiTiMorCHROMous CHLORIDE. CrCl. (Moberg, 
 J.pr. Chem. xxix. 175; Peligot, Ann. Ch. Phys. [3] xii. 527.) This compound is ob- 
 tained by passing hydrogen gas over perfectly anhydrous sesquichloride of chromium 
 very gently heated, as long as hydrochloric acid gas continues to escape. The hydrogen 
 must be previously freed from all traces of oxygen by passing it through a solution 
 of protochloride of tin in caustic potash, then through tubes containing sulphuric acid 
 and chloride of calcium, and lastly over red-hot metallic copper. The protochloride is 
 also formed by passing dry chlorine gas over a red-hot mixture of charcoal and chromic 
 oxide. The first method yields the protochloride in the form of a white, velvety sub- 
 stance, retaining the form of the sesquichloride from which it has been formed ; the 
 second method yields it in fine white crystals, usually mixed, however, with chromic 
 oxide, chromic chloride, and charcoal. 
 
 Protochloride of chromium dissolves in water, with evolution of heat, forming a blue 
 solution, which rapidly turns green when exposed to the air or to chlorine gas. With 
 potash it forms a dark brown precipitate (yellow, according to Moberg, if the air be com- 
 pletely excluded) of hydrated chromous oxide, which, however, quickly changes to light 
 brown chromosochromic oxide, with evolution of hydrogen. Ammonia forms a sky- 
 blue precipitate, which turns green on exposure to the air. With ammonia and sal- 
 ammoniac, a blue liquid is formed, which turns red on exposure to the air. Sulphide 
 
942 CHROMIUM: CHLORIDES. 
 
 of ammonium or potassium forms a black precipitate of chromous sulphide. The solu- 
 tion of proto chloride of chromium is one of the most powerful deoxidising agents known. 
 With a solution of neutral chromate of potassium, it forms a dark brown precipitate 
 of chromosochromic oxide, which, however, disappears on the addition of an excess 
 of the protochloride, and forms a green solution. It precipitates calomel from a solu- 
 tion of corrosive sublimate. With cupric salts, it forms at first a white precipitate of 
 cuprous chloride, but when added in excess, throws down red cuprous oxide. It in- 
 stantly converts tungstic add into blue oxide of tungsten, and precipitates gold from 
 the solution of the chloride. 
 
 A solution of chromous chloride containing zinc, may be obtained, according to 
 Loewel (J. pr. Chem. Ixii. 11), by pouring a solution of the sesquichloride, or of 
 chrome-alum, in 3 to 5 pts. water, made as neutral as possible, into a bottle nearly 
 filled with granulated zinc. Hydrogen is then evolved for some hours, and a fine blue 
 liquid is formed, which, if left to stand in contact with the zinc, continues slowly to 
 evolve hydrogen and deposit a light grey chromous oxychloride, and after four or six 
 months becomes perfectly colourless. 
 
 SESQUICHLORIDE OF CHROMIUM. Chromic Chloride. Cr 2 CP. The anhy- 
 drous sesquichloride is prepared by igniting an intimate mixture of chromic oxide and 
 charcoal in a stream of dry chlorine gas. A mixture of the oxide with lamp-black is made 
 up into pellets with starch ; these are well baked in a covered crucible, and then in- 
 troduced into another crucible, through the bottom of which there passes a porcelain 
 tube connected with an apparatus for evolving chlorine. Into the mouth of this crucible 
 is fitted a smaller one, placed in an inverted position. The lower crucible stands on 
 the grate of an ordinary air-furnace, and, as soon as the apparatus is filled with dry 
 chlorine, the mixture is heated to bright redness, the firing being so regulated as to 
 keep the upper crucible comparatively cool, so that the chloride as it is produced may 
 sublime into it. When the process is completed, the stream of chlorine must be kept 
 up till the apparatus is cool, to prevent the formation of sesquioxide or protochloride. 
 The sesquichloride is then washed with water to free it from chloride of aluminium 
 derived from the crucible. If it contains protochloride, which is the case if the stream 
 of chlorine has not been strong enough, it will dissolve during washing ( W 6 h 1 e r, Pogg. 
 Ann. xi. 148). The sesquichloride may also be obtained by heating the sesquisulphida 
 in a stream of dry chlorine. (Berzelius.) 
 
 Anhydrous chromic chloride forms shining micaceous laminae of a beautiful peach- 
 blossom colour, which may be rubbed on the skin like talc. It is quite insoluble in 
 cold water ; but, if boiled in the finely divided state with water, it slowly dissolves and 
 forms a green solution. If the cold water contains in solution a small quantity of 
 chromous chloride, not even exceeding ^^ to y^, the sesquichloride dissolves imme- 
 diately, with evolution of heat, forming a green solution identical with that obtained 
 by dissolving chromic hydrate in hydrochloric acid. This effect is perhaps due to the 
 formation of an intermediate chloride, which is immediately resolved by the action of 
 water into protochloride and the soluble green modification of the sesquichloride, the 
 protochloride thus liberated again acting in the same manner (see p. 943). The addi- 
 tion of a small quantity of stannous or cuprous chloride is said to produce the same 
 effect. 
 
 Anhydrous chromic chloride is not decomposed by sulphuric acid, either strong or 
 dilute, or by hydrochloric, nitric, or nitromuriatic acid, or by ammonia, carbonate of 
 potassium, or carbonate of sodium : caustic potash attacks it but slightly at the boiling 
 heat. Fused with nitre and an alkali or alkaline carbonate, it yields a chromate and 
 chloride of the alkali-metal. Potassium, zinc, &c., separate metallic chromium from 
 it. Heated in a stream of hydrogen, it yields chromous chloride, and if the heat be 
 strong, metallic chromium is likewise separated. Heated to redness in the air, it gives 
 off chlorine and yields green chromic oxide. By ignition in phosphoretted hydrogen 
 gas, it is converted into phosphide of chromium. Heated with sulphur, or in a stream 
 of sidphydric acid gas, it yields sulphide of chromium. Ignited in ammonia gas, it 
 forms nitride of chromium. 
 
 By dissolving chromic oxide in hydrochloric acid, or by boiling chromate of lead or 
 silver with hydrochloric acid and alcohol, or even with excess of hydrochloric acid alone, 
 a green solution is obtained, containing the modification of chromic chloride which cor- 
 responds to the green chromic oxy-salts (p. 950). This solution, when evaporated, 
 yields a non-crystalline dark green syrup, which, when heated to 100 C. in a stream 
 of dry air, yields a green mass containing 2Cr 2 CP.9H 2 (Moberg, J. pr. Chem. xxix. 
 175). The same solution evaporated in vacuo yields green granular crystals containing 
 Cr 2 Cl s .H 2 0. (P e 1 i g o t, ibid, xxxvii. 475.) 
 
 Hydrated chromic chloride heated to 250 C. in a stream of hydrochloric acid or 
 chlorine gas, gives off its water and yields delicate peachblossom-coloured scales, which 
 are soluble in water and even deliquescent; but, if more strongly heated in either of 
 
CHROMIUM: DETECTION AND ESTIMATION. 943 
 
 these gases, it begins to sublime, and the sublimed chloride thus obtained is insoluble 
 in water, like that obtained by igniting chromic oxide with charcoal in a stream of 
 chlorine. The anhydrous chloride cannot be obtained by heating the hydrated chloride 
 in the air : for hydrochloric acid is then given off and soluble oxychloride produced, 
 afterwards an insoluble oxychloride, and the residue ultimately consists of green 
 chromic oxide. In this respect, the hydrated sesquichloride of chromium resembles the 
 corresponding compounds of iron and aluminium. 
 
 Nitrate of silver added to a g r e e n solution of chromic chloride, throws down at first 
 only g of the chlorine ; but on leaving the liquid to stand, or on boiling it, the whole 
 of the chlorine is precipitated. This effect was attributed by Berzelius to the tendency 
 of chromic chloride to form double salts ; by Otto to the solubility of chloride of silver 
 in chromic nitrate. 
 
 A solution of chromic chloride, corresponding to the violet solutions of the chromic 
 salts of oxygen-acids, may be obtained by precipitating one of these violet salts by an 
 alkali, and dissolving the precipitated hydrate in hydrochloric acid ; also by decom- 
 posing the violet sulphate with chloride of barium. From these solutions nitrate of 
 silver immediately throws down all the chlorine. If, however, the violet solution of 
 the chloride be boiled, it turns green, and after this change the chlorine is but partially 
 precipitated by nitrate of silver. 
 
 Chromic chloride unites with the chlorides of the more basic metals, forming salts 
 containing MCl.Cr 2 Cl 3 , or MCr 2 Cl 4 , of which however only the potassium, sodium, and 
 ammonium-compounds have been investigated. They are obtained by mixing the cor- 
 responding acid chromates with excess of hydrochloric acid and alcohol, and evaporating 
 over the water-bath till the mass turns violet. The double chlorides thus obtained 
 become green and deliquesce on exposure to the air. Treated with a small quantity 
 of cold water, they dissolve, with deep yellowish-red colour, which in a short time 
 passes into pure chrome-green. If the solution be then left to evaporate, the alkaline 
 chloride separates out, and the chromic chloride remains in the form of a green syrup. 
 These double chlorides belong therefore to the violet modifications of chromic salts, but 
 are decomposed by water into chloride of alkali-metal and green chromic chloride, 
 which does not form double chlorides. The effect of chromous, stannous, and cuprous 
 chlorides in facilitating the solution of anhydrous chromic chloride in water (p. 942) 
 probably depends upon the formation of analogous double chlorides. If the double 
 chloride decomposed by slow evaporation be mixed with hydrochloric acid and evapo- 
 rated to dryness over the water-bath, the double chloride is reproduced. When the dry 
 double chlorides are treated with absolute alcohol, green chromic chloride dissolves, 
 and a rose-coloured salt remains, consisting, according to Eerzelius, of 3MCl.Cr 2 Cl s . 
 
 CHROMIUM, DETECTION- ATTD ESTIMATION" OP. 1. All compounds 
 of chromium ignited with a mixture of nitre and an alkaline carbonate yield a chromate 
 of the alkali-metal, which may be dissolved out by water, and on being neutralised 
 with acetic acid, will give the characteristic precipitates of chromic acid with lead and 
 silver-salts. 
 
 The oxides of chromium and their salts, fused with borax in either blowpipe flame, 
 yield an emerald-green glass. The same character is exhibited by those salts of 
 chromic acid whose bases do not of themselves impart decided colours to the bead. 
 The production of the green bead in both flames distinguishes chromium from ura- 
 nium and vanadium, which give green beads in the inner flame only. 
 
 2. Reactions in Solution. The sesqui-salts of chromium or chromic salts 
 exhibit two principal modifications, the green and the violet. Ammonia produces in 
 solutions of the green salts, a greyish-green precipitate ; in solutions of the violet salts, 
 a greyish-blue precipitate, both of which however yield green solutions with sulphuric 
 or hydrochloric acid. The liquid above the precipitate has a reddish colour, and con- 
 tains a small quantity of chromic acid. Potash and soda form similar precipitates, 
 which dissolve in excess of the alkali, forming green solutions from which the chromic 
 oxide is precipitated by boiling. The alkaline carbonates form greenish precipitates 
 (violet by candle-light) which dissolve to a considerable extent in excess of the reagent, 
 Sulphydric add forms no precipitate ; sulphide of ammonium throws down the hydrated 
 sesquioxide. 
 
 Zinc, immersed in a solution of chrome-alum or sesquichloride of cliromium, excluded 
 from the air, gradually reduces the chromic salt to a chromous salt, the liquid after a 
 few hours acquiring a fine blue colour, and hydrogen being evolved by decomposition 
 of water. If the zinc be left in the liquid after the change of colour from green to blue 
 is complete, hydrogen continues to escape slowly, and the liquid, after some weeks or 
 months, is found no longer to contain chromium, the whole of that metal being pre- 
 cipitated in the form of a basic salt, and its place taken by zinc. Tin, at a boiling 
 heat, likewise reduces the chromic salt to a chromous salt, but only to a limited extent ; 
 
944 CHROMIUM: ESTIMATION. 
 
 and on leaving the liquid to cool after the action has ceased, a contrary action takes 
 place, the protochloride of chromium decomposing the protochloride of tin previously 
 formed, reducing the tin to the metallic state, and being itself reconverted into sesqui- 
 chloride. Iron does not reduce chromic salts to chromous salts, but merely precipitates 
 a basic sulphate of chromic oxide, or an oxychloride, as the case may be. 
 
 Chromous salts are but rarely met with in solution : for their characters, see PROTO- 
 CHLORIDE OF CHROMIUM (p. 942). 
 
 Chromic acid and its salts are recognised in solution by forming a pale yellow pre- 
 cipitate with barium-salts, bright yellow with lead-salts, brick red with mercurous-salts, 
 and crimson with silver-salts (p. 932). 
 
 3. Quantitative Estimation. Chromium is usually estimated in the state of 
 sesquioxide. When it exists in solution as a sesqui-salt, it may be precipitated by 
 ammonia, care being taken to avoid a large excess of that reagent (which would dissolve 
 a portion), and to heat the liquid for some time. The chromic oxide is then com- 
 pletely precipitated, and the precipitate, after washing and drying, is reduced by 
 ignition to the state of anhydrous sesquioxide, containing 69'1 per cent, of the metal. 
 
 When chromium exists in solution in the state of chromic acid, it is best to precipi- 
 tate it by a solution of mercurous nitrate ; the mercurous chromate thereby thrown 
 down yields by ignition the anhydrous sesquioxide. The chromic acid might also be 
 precipitated and estimated in the form of a barium or lead-salt. 
 
 Chromic acid may also be estimated by means of oxalic acid, which reduces it to 
 sesquioxide, being itself converted into carbonic acid. The quantity of carbonic anhy- 
 dride evolved determines the quantity of anhydrous chromic acid present, 3 at. CO 2 
 corresponding to 1 at. Cr 2 s , as shown by the equation : 
 
 3C 2 H 2 4 = Cr 4 s + 6C0 2 + 3H 2 0. 
 
 The mixture may be heated in the carbonic acid flask represented in fig. 5, p. 119. 
 If the object be merely to determine the quantity of chromium present, any salt of oxalic 
 acid may be used ; but if the alkalis are also to be estimated in the remaining liquid, 
 the ammonium or barium-salt must be used. 
 
 Lastly, chromic acid may be estimated by Bunsen's volumetric method. The chromic 
 acid is decomposed by boiling with excess of hydrochloric acid, whereupon 1 at. chromic 
 anhydride eliminates 3 at. chlorine : 
 
 Cr 2 8 + 6HC1 = Cr'Cl 8 + 3H 2 + Cl 3 ; 
 
 and the 3 at. chlorine passed into a solution of iodide of potassium, liberate 3 at. 
 iodine, which is estimated by a standard solution of sulphurous acid, as described under 
 VOLUMETRIC ANALYSIS (p. 264), so that 3 at. iodine correspond to 1 at. Cr 2 3 . 
 
 4. Separation of Chromium from other Elements. Chromic oxide, in 
 the state of neutral or acid solution, is easily separated from the alkalis or alkaline 
 earths by precipitation with ammonia, care being taken in the latter case to protect the 
 liquid and precipitate from the air. The same method, with addition of sal-ammoniac, 
 serves to separate chromic oxide from magnesia. The separation from the alkaline 
 earths and from magnesia may also be effected by precipitating the whole with an 
 alkaline carbonate, and igniting the precipitate with a mixture of carbonate of sodium 
 and nitre. The chromium is then converted into chromate of sodium, which may be 
 dissolved out, and the solution, after neutralisation with nitric or acetic acid, treated 
 with mercurous nitrate as above. 
 
 From alumina and glucina, chromic oxide may be separated by treating the solution 
 with excess of potash, and boiling the liquid to precipitate the chromic oxide. The 
 separation is, however, more completely effected by fusing with nitre and carbonate of 
 sodium, treating the fused mass with water, adding an excess of nitric acid to dissolve 
 anything that may be insoluble in water, and precipitating the alumina or glucina by 
 ammonia. 
 
 Another method of converting chromic oxide into chromic acid, and thereby effecting 
 its separation from the above-mentioned oxides, is to treat the mixture with excess of 
 potash, and heat the solution gently with peroxide of lead. The whole of the chro- 
 mium is then converted into chromic acid, and remains dissolved as chromate of lead 
 in the alkaline liquid ; and on filtering from the excess of peroxide of lead, and any 
 other insoluble matter that may be present, and supersaturating the filtrate with acetic 
 acid, the chromate of lead is precipitated. (Chancel, Compt. rend, xliii. 927.) 
 
 Chromic acid may be separated from the alkalis in neutral solutions by precipita- 
 tion with mercurous nitrate ; also by reducing it to chromic oxide with hydrochloric acid 
 and alcohol, and precipitating by ammonia. From the earths it may also be separated 
 by this latter method, or, again, by fusing with carbonate of sodium, dissolving out 
 with water, &c. 
 
 From iron, zinc, nickel, cobalt, uranium, and cerium, chromium may be separated by 
 
CHROMIUM : ESTIMATION OF. 945 
 
 fusion with nitre and carbonate of sodium, or with the carbonate alone if it is already in 
 the form of chromic acid. Or, again, the separation may be effected by means of potash 
 and peroxide of lead, according to Chancel's method above described. 
 
 The separation of chromium from manganese cannot be effected immediately in this 
 manner, because the manganese is at the same time converted into manganate or per- 
 manganate of sodium ; but on dissolving in water and adding alcohol to the solution, 
 the manganese is reduced to peroxide and completely precipitated, while the chromium 
 remains dissolved as chromate. 
 
 From titanium, tantalum, and columbium, chromium, if in the state of sesquioxide, 
 may be separated by fusing the mixture with nitre and alkaline carbonate, extracting 
 with water, reducing the chromium to the state of sesquioxide by boiling with hydro- 
 chloric acid, and precipitating by ammonia. 
 
 From copper, lead, tin, and the other metals of the first group (p. 217), chromium 
 is separated by sulphydric acid. 
 
 To estimate chromic acid in presence of sulphuric acid, the chromium is first re- 
 duced to sesquioxide as above ; the sulphuric acid is then precipitated, after conside- 
 rable dilution, by chloride of barium ; the excess of barium is removed by sulphuric 
 acid : and the chromic oxide precipitated by ammonia. 
 
 When phosphoric acid is present in solution, together with chromic acid, the phos- 
 phoric acid is precipitated as phosphate of magnesium and ammonium, and then the 
 chromic acid by any of the preceding methods. 
 
 Hydrochloric acid is separated from chromic acid by nitrate of silver, and the excess 
 of silver is removed by sulphuretted hydrogen, the chromic acid being at the same 
 time reduced to sesquioxide, which may be precipitated by ammonia. 
 
 Silicic acid is separated from chromic acid in the same manner as from all other 
 substances, and the chromium is afterwards precipitated as oxide. 
 
 When sesquioxide of chromium and chromio acid occur together in solution, the 
 chromic acid may be precipitated by mercurous nitrate, the solution being first com- 
 pletely neutralised, and the sesquioxide precipitated from the filtrate by ammonia, 
 which at the same time throws down a mercury-compound, to be afterwards separated 
 from the chromic acid by ignition. 
 
 Valuation of Chrome-ores. The value of a chrome-ore depends upon the 
 quantity of chromic acid that it will yield. To ascertain this point, the ore is calcined 
 with a mixture of nitre, alkali, and lime, the use of the lime being to keep the mixture 
 in a pasty condition, and prevent the heavy ore from falling to the bottom (see p. 936), 
 after which the soluble chromate is extracted, and the amount of chromic acid may 
 then be determined by any of the methods already given. 
 
 Professor Calvert of Manchester, has given two processes for the valuation of chrome 
 ores. (Chem. Soc. Qu. J. v. 194.) 
 
 a. The ore in fine powder is mixed with three or four times its weight of soda-lime 
 (obtained by slaking quick lime with caustic soda, then drying and calcining the mass), 
 and to this mixture of soda-lime and ore is added one-fourth of nitrate of sodium. The 
 whole is then well calcined for two hours, care being taken to stir the pasty mass 
 every quarter of an hour with a platinum wire. This mixture not becoming fluid, the 
 ore is constantly kept in contact with the oxygen of the atmosphere, and thus the oxide 
 of chromium is converted into chromic acid. One treatment is generally sufficient for 
 the complete decomposition of the ore. 
 
 The greater part of the mass is now dissolved in water, and the insoluble portion 
 treated with sulphuric acid diluted with twice its bulk of water ; the whole is then re- 
 moved from the crucible, and a little alcohol is added to the solution in order to render 
 the sulphate of calcium insoluble. The whole is next thrown on a filter and washed with 
 weak alcohol, which dissolves all the acid chromate formed, and leaves the sulphate of 
 calcium, together with any portion of ore that may not have been attacked. The sul- 
 phate of calcium may be removed by washing the filter with boiling water, and the 
 residual ore, if any, is to be recalcined. 
 
 The solution containing the acid chromate of sodium is now neutralised with 
 ammonia, and oxalate of ammonium is added, which gives rise to a small precipitate of 
 sesquioxide of iron, alumina, and oxalate of calcium, together with a little silica dis- 
 solved by the sulphuric acid. The precipitate having been separated and well washed, 
 the liquor is either mixed with alcohol to reduce the chromic acid to the state of ses- 
 quioxide, which may then be precipitated, washed, dried, ignited, and weighed ; or, 
 better, the liquor is rendered acid, and the amount of chromic acid estimated by 
 Penny's process (Chem. Soc. Qu. J. iv. 239) with dichloride* of tin (commonly called 
 <protochloride}. This method depends on the reaction of dichloride of tin with acid 
 chromate of sodium or potassium in presence of free hydrochloric acid, whereby 
 
 * Atomic weight of tin = 118. 
 
 VOL. I. 3 P 
 
946 CHROMIUM: FLUORIDES. 
 
 the dichloride of tin is converted into tetrachloride, and the chromic acid into sesqui- 
 chloride of chromium : 
 
 3SnCl 2 + 2NaCr0 2 .Cr 2 3 + 14HC1 = 3SnCl 4 + 2NaCl + 7H 2 + 2Cr 2 Cl s . 
 
 A solution of dichloride of tin of known strength* is added to the solution of acid 
 chromate of sodium, till the latter is completely decomposed, which may be known by 
 the solution no longer giving a yellow precipitate with acetate of lead and the 
 quantity of acid chromate present is calculated from the amount of tin in the solution 
 used. Penny has shown, by direct experiment, that in the above reaction, 100 pts. of 
 metallic tin correspond to 83*2 pts. of acid chromate of potassium, or 78-4 pts. of acid 
 chromate of sodium. 
 
 b. The finely divided ore is calcined with nitrate of barium, a small quantity of 
 caustic potash being added towards the end of the operation to facilitate the action, and 
 give rise to chromate of potassium. The pasty condition of the fused baryta prevents 
 the ore from falling to the bottom, and thus keeps it in contact with the air. On cooling, 
 the crucible and its contents are immersed in dilute nitric acid, which dissolves the 
 greater portion of the mass, leaving the unattacked ore, which, after being washed, 
 may be recalcined. The liquor containing the acid chromates of potassium and 
 barium, nitrate of barium, sesquioxide of iron, alumina, and lime, is first heated with 
 sulphate of potassium, which throws down the baryta as sulphate, which is collected on 
 a filter and washed ; ammonia and oxalate of ammonium are then added to throw 
 down sesquioxide of iron, alumina, and lime ; the mixed precipitate is collected and 
 washed ; and the amount of chromic acid determined as before. 
 
 5. Atomic Weight of Chromium. Berzelius, in 1818 (Schw. J. raj. 53), esti- 
 mated the atomic weight of chromium from the composition of chromate of lead. 100 
 pts. nitrate of lead (containing 6 7 '31 Pb 2 0), yielded by precipitation with chromate of 
 potassium, 98*772 pts. Pb 2 O.Cr 2 3 ; whence, taking the atomic weight of lead at 
 103*59, that of chromium was found to be 28*14. 
 
 Pe"ligot, in 1844 (Ann. Ch. Phys. [3] xii. 528), showed that this number was too 
 high. From the analysis of chromous chloride, CrCl, in which he found 56*7 to 58*4 
 per cent, chlorine, and likewise from that of the acetate, he estimated the atomic weight 
 of chromium at 26*24. 
 
 Berlin (Ann. Ch. Pharm. Ivi. 207; lx. 182), analysed chromate of silver by pre- 
 cipitating the silver with hydrochloric acid, then reducing the chromic acid in the 
 filtrate to chromic oxide, and precipitating by ammonia. From the quantity of chloride 
 of silver obtained (Ag = 108; 01 = 35*206), he found, as a mean of five experiments, 
 Or = 26*34, and by comparing the quantity of chromic oxide precipitated with the 
 original quantity of chromate of silver, Or = 26*27. 
 
 Berlin likewise adopted the method of Berzelius, and found that 100 pts. nitrate of 
 lead yield from 97*559 to 97*594 pts. chromate of lead, whence, as a mean result, 
 Or = 25*99. 
 
 Moberg, in 1841 (J. pr. Chem. xliii. 114; xliv. 322), estimated the atomic weight 
 of chromium by the analysis of chromic sulphate and of ammoniacal chrome-alum. 
 From the quantity of chromic oxide in the sulphate dried at 300 C. he found Or = 26*55; 
 from that which remained after heating ammonio-chrome-alum to bright redness, 
 Cr = 26*78. _ 
 
 Lefort, in 1850 (J. Pharm. [3] xviii. 27), determined the quantity of baryta in 
 chromate of barium, by dissolving the salt in nitric acid and precipitating by sulphuric 
 acid. In fourteen experiments, he found that 100 pts. chromate of barium yielded 
 60*35 to 60*01 baryta; mean 60*19: whence, if Ba = 68*56, Or = 26 -64. 
 
 Lastly, Wildenstein, in 1853 (J. pr. Chem. lix. 27), determined the quantity of 
 chromate of barium precipitated from chloride of barium by neutral chromate of 
 potassium. As a mean of 32 experiments, he found that 100 pts. chromate of barium 
 correspond to 81*70 of the chloride ; the limits were 81*52 and 81*86. If then Ba = 
 68*56 and 01 = 35*46, the value of Or is 26*76. 
 
 As the precipitation of baryta by sulphuric acid is affected by an error arising from 
 the carrying down of a portion of the dissolved salt with the precipitated sulphate, and 
 as moreover the atomic weight of barium is not very exactly known, it is probable 
 that the determinations of the atomic weight of chromium by Berlin and by Peligot, 
 are the most exact, and the number 26*24 may be considered very near to the true 
 value. (Handw. d. Chem. 2 te Aufl. ii. [1] 482.) 
 
 CHHOIttlTTlVT, FZiUOniBSS OF. The sesquifluoride, CrT 8 , is obtained 
 by treating the se^quioxide, dried, but not ignited, with excess of hydrofluoric acid, 
 and heating the dried mass very strongly in a platinum crucible. It is dark green, 
 melts at a high temperature, and is but very slightly volatile, even at the melting 
 point of steel. When subjected to the highest temperature produced by a lamp urged 
 
 * The strength of a solution of dichloride of tin is most easily ascertained by means of a standard 
 solution of pure acid chroinate of potassium. 
 
CHROMIUM: IODIDES OXIDES. 947 
 
 by bellows, it sublimes in shining regular octahedrons (Deville, Ann. Ch. Pharm. 
 cl. 197). Berzelius obtained it as a green crystalline saline mass. 
 
 Chromic fluoride unites with the fluorides of ammonium, potassium, and sodium, 
 forming green sparingly soluble compounds. 
 
 Trifluoride, CrF 3 . This compound, discovered by Unverdorben, is obtained by 
 distilling 1 pt of chromate of lead with 1 pt. fluor spar and 3 pts. fuming oil of 
 vitriol in a leaden retort, and collecting the vapours in a perfectly dry leaden receiver 
 kept at a very low temperature: it then condenses to a blood-red, strongly fuming liquid, 
 which becomes gaseous again at a temperature very little higher. The vapour is red, 
 and when inhaled, produces violent coughing and severe oppression of the lungs. It 
 is decomposed by water, forming hydrofluoric and chromic acids, and when it mixes 
 with the air, forms a thick white fume, coloured orange-yellow on the edges by minute 
 particles of chromic acid. With ammonia it unites, according to Unverdorben, forming 
 a yellow volatile body ; but, according to Berzelius, it is decomposed with slight ex- 
 plosion, producing nitrogen gas, water, and hydrofluoric acid. Metals and other 
 reducing agents, organic as well as inorganic, abstract part of the fluorine, leaving the 
 sesquifluoride. Silicic acid decomposes it immediately, forming fluoride of silicium 
 and chromic acid ; hence it corrodes glass ; it may be kept, however, for a while in 
 glass vessels coated with resin. 
 
 H. Hose (Pogg. Ann. xxvii. 565), supposed that the formula of this compound was 
 CrF 5 , because it contains more fluorine than the formula CrF 3 requires, and its decom- 
 position by water is attended with evolution of oxygen, as well as the formation of 
 chromic and hydrofluoric acids. Berzelius, on the contrary, was of opinion that the 
 excess of fluorine above 3 atoms arose from admixture of hydrofluoric acid, and that the 
 evolution of oxygen in its decomposition by water, was due to the previous mixture of 
 that gas with the vapour of the fluoride, inasmuch as the residue obtained in the pre- 
 paration of the compound always contains chromic oxide. 
 
 A fluoride of intermediate composition between the sesqui- and tri-fluorides is ob- 
 tained in solution by dissolving brown oxide of chromium in hydrofluoric acid. The 
 solution is red, and yields by evaporation a rose-coloured salt, which is redissolved 
 without alteration by water, and precipitated brown by ammonia. 
 
 CHROMIUM, IODIDES OP. Thesesqui-iodide, Cr 2 ! 3 , is obtained in solution 
 by dissolving chromic hydrate in hydriodic acid, or by treating chromate of silver with 
 hydriodic acid and alcohol. It is green, and yields by evaporation a green glassy 
 residue, which splits into small pieces on cooling. It is insoluble in cold, easily 
 soluble in warm water, but does not separate out again on cooling. No other iodide of 
 chromium is known with certainty. 
 
 CHROIMIUIYI, NITRIDE OP. Cr'N*? This compound is produced when 
 sesquichloride of chromium is heated in a stream of ammonia-gas: probably thus : 
 
 13NH 3 = 2Cr 3 N 2 + 9NH 4 C1 + H 3 ; 
 
 also when chlorochromic anhydride is treated in a similar manner. It is a brown 
 powder, which, when heated to 150 200 C. in a stream of oxygen, takes fire and 
 burns with a red light, giving oif nitrogen gas and a small quantity of pernitric oxide, 
 and leaving sesquichloride of chromium. (Liebig, Pogg. Ann. xxi. 359. Schrotter, 
 Ann. Ch. Pharm. xxxvii. 148. -Gm. iv. 139.) 
 
 CHROMIUM, OXIDES OP. Chromium forms several compounds with oxygen, 
 namely, the protoxide, Cr 2 O, the scsquiomde, Cr'O 3 , the trioxide, or chromic anhydride, 
 Cr'-O 3 ; also an oxide, Cr'O 2 , intermediate between Cr 2 and Cr 4 3 , and several oxides 
 intermediate between Cr 4 3 and Cr 2 3 . 
 
 PROTOXIDE OF CHROMIUM. CHROMOUS OXIDE, CrH). (Moberg, J.pr.Chem. 
 xliv. 322. Peligot, Ann. Ph. Phys. [3] xii. 528.) This oxide probably exists in some 
 specimens of chrome-iron ore (p. 939) and in pyrope. It is precipitated as a hydrate 
 by the action of potash on a solution of the protochloride. The anhydrous protoxide 
 has not been obtained. The hydrate, 2Cr 2 O.H 2 0, is very unstable, decomposes water 
 even at ordinary temperatures, and unless carefully protected from the air, by preci- 
 pitating with a well-boiled solution of potash, is converted, as soon as it is formed, into 
 chromoso-chromic oxide, with evolution of hydrogen. It must be dried in an atmo- 
 sphere of hydrogen. It is yellow when recently precipitated, brown when dry, and 
 may be preserved unaltered in dry air. When ignited, it gives off hydrogen and leaves 
 sesquioxide : 2Cr 2 O.H 2 = Cr 4 3 + H 2 . 
 
 Chromous hydrate is insoluble in dilute acids, but dissolves slowly in strong acids. 
 The chromous salts are most easily prepared by mixing a solution of the proto- 
 chloride with the potassium or sodium-salt of the corresponding acid. They are 
 generally of a red colour, sometimes inclining to blue, dissolve but sparingly in cold 
 water, more readily in hot water. Like ferrous salts, they dissolve large quantities of 
 
 3 P 2 
 
948 CHROMIUM: OXIDES. 
 
 nitric oxide, forming dark brown solutions. (For their other reactions', see TKOTO- 
 CHI.ORIDE OF CHROMIUM, p. 942.) 
 
 CHROMOSO-CHROMIC OXIDE, Cr s 2 , or Cr 2 O.Cr 4 3 . Formed when protochloride 
 of chromium is precipitated by potash without the precautions above mentioned for 
 excluding the air. After washing in water and drying in the air, it has the colour of 
 Spanish tobacco. It is but slightly attacked by acids. 
 
 SESQUIOXIDE OF CHROMIUM. CHROMIC OXIDE, Cr 4 3 . This oxide exists in 
 chrome-iron ore (p. 939). and in chrome-ochre. The latter occurs as a yellowish-green, 
 earthy or argillaceous deposit generally mixed with clay, in the Shetland Isles, at Creuzot 
 in France, at Halle and Waldenburg in Silesia, at Martenberg in Sweden, &c. (Dana, 
 ii. 339). It is produced by heating chromium to redness in the air, by the ignition of 
 chromic hydrate, by the decomposition of chromic anhydride and of various chromates, 
 some of these processes yielding it in the amorphous, others in the crystalline state. 
 
 a. Amo?'phoits. 1. When mercurous chromate is heated as long as oxygen and 
 vapour of mercury are evolved, chromic oxide remains of a very fine green colour. 
 It is best to heat the salt in a covered crucible, since, if the air has free access to it, part 
 of the sesquioxide is converted into brown oxide, which impairs its colour. (Otto.) 
 2. "When acid chromate of potassium is heated to redness with sulphur, the chromic 
 acid is reduced, sulphurous anhydride is evolved, and there remains a mixture of 
 chromic oxide with sulphide and sulphate of potassium, from which the soluble salts 
 may be extracted by water. (Lassaigne, Ann. Ch. Phys. [3] xiv. 299.) 3. Berthier 
 ignites chromate of potassium in a charcoal crucible, or mixes it with charcoal powder 
 or lamp-black, and ignites it in an ordinary earthen crucible ; dissolves the chromite of 
 potassium produced in cold water; heats the filtrate to the boiling point; collects the 
 precipitated hydrate on a filter ; washes it thoroughly with water ; and lastly ignites it. 
 4. Wo hler (Pogg. Ann. x. 46) ignites a mixture of acid chromate of potassium with 
 about its own weight of sal-ammoniac and a small quantity of carbonate of sodium 
 in a covered crucible, till no more vapour of sal-ammoniac is disengaged ; and then 
 purifies the sesquioxide of chromium from chlorides of potassium and sodium, by 
 washing with water. 5. Barian (Rev. scient. xx. 425) mixes 4 pts. of acid chromate 
 of potassium with 1 pt. of starch ; ignites the mixture in a crucible ; washes away 
 the resulting carbonate of potassium, with water ; and again ignites the residue. He 
 states that the chromic oxide thus obtained is so pure that it may be used for glazing 
 porcelain. 6. When acid chromate of ammonium is heated in a platinum or porce- 
 lain basin over a lamp, a very energetic action takes place, accompanied by strong 
 incandescence, and green bulky masses of chromic oxide shoot out in every direction, 
 very much resembling unopened tea-leaves. (Bottger, Ann. Ch. Pharm. xlvii. 332.) 
 7. A very fine and intimate mixture is made of 48 pts. of gunpowder, 240 pts. of 
 perfectly dry acid chromate of potassium, and 5 pts. of equally dry chloride of ammo- 
 nium. This mixture is made into the shape of a cone (by pressing it into a wine 
 glass, and afterwards carefully shaking it out) and then transferred to an iron plate. 
 A burning fusee or other combustible is then applied to the top of the cone, where- 
 upon it takes fire, and slowly burns throughout its whole mass. On exhausting the 
 cone, while still hot, with water, a residue of chromic oxide is obtained in the form of a 
 pale green powder. (Bottger, loc. cit.~] 
 
 b. Crystallised. 1. When vapour of chloro-chromic anhydride is slowly passed 
 through a glass tube heated to low redness, chlorine and oxygen are evolved, and 
 chromic oxide remains in the tube as a crystalline deposit, sometimes interspersed with 
 larger crystals (Wohler, Ann. Ch. Pharm. Ix. 203). 2. When acid chromate of 
 potassium is heated to whiteness for eighteen hours, a mixture of the neutral chro- 
 mate and chromic oxide is obtained ; and on dissolving out the former with water, 
 chromic oxide remains in fine iridescent spangles (Grentele, J. p. Chem. liv. 184). 
 3. When dry chlorine is passed over chromate of potassium heated to redness in a 
 porcelain tube, the gas is completely absorbed, oxygen is evolved, and chloride of potas- 
 sium is formed, together with chromic oxide, in long, shining, green, brittle tablets, if 
 the tube is heated only to a dull redness, but in hard brown crystals like those ob- 
 tained by Wohler's method, if the temperature is raised to bright redness (Fremy, Ann. 
 Ch. Pharm. xlix. 274). Blake (ibid. cii. 331) found chromic oxide crystallised in 
 plates having the metallic lustre and belonging to the hexagonal system, in the cracks 
 of a furnace which had been used for a long time for the preparation of chromate of 
 potassium from chrome-iron ore. 
 
 Crystallised chromic oxide prepared by Wohler's method forms crystals of rhombo- 
 hedral character, greenish-black with metallic lustre, and as hard as corundum, so 
 that they scratch glass. Their specific gravity is 5'21, and they yield a greenish 
 powder by trituration. 
 
 Amorphous chromic oxide obtained by decomposing the hydrate at a temperature 
 below redness, has a dark green colour; that which has been strongly ignited (methods 
 
CHROMIUM: OXIDES. 949 
 
 1 to 7 p. 948) is bright green. When the oxide prepared at a moderate heat is gradu- 
 ally raised to a higher temperature, it suddenly becomes incandescent and is after- 
 wards nearly insoluble in acids. According to Berzelius, it then contains the indif- 
 ferent modification of chromium (p. 941). By ignition with nitrate or acid sulphate 
 of potassium, it may be brought back to the soluble state. 
 
 Amorphous chromic oxide melts at the heat of a forge-fire, and on cooling forms 
 a greenish-black crystalline mass, exhibiting all the properties of the crystalline oxide 
 obtained by Wohler's method. It is not reduced by hydrogen gas. Charcoal reduces 
 it at an intense white heat, but only at the points where it is in contact with the 
 charcoal. 
 
 Chromic oxide is used in the preparation of green glass and enamel, but especially 
 in the painting of porcelain. It is also used in ordinary painting, forming one of the 
 most permanent greens, called chrome-green. 
 
 Hydrated Chromic Oxide. Chromic Hydrates. Chromic oxide forms 
 several hydrates differing in their properties. When a solution of a green or violet 
 chromic salt is mixed with potash or soda, a bluish-green hydrate is precipitated, 
 which dissolves with emerald-green colour in excess of the precipitant, but is repre- 
 cipitated completely as green hydrate on boiling. With ammonia, the violet salts give 
 a grey -blue, the green salts a grey-green precipitate. Both these precipitates dissolve 
 in cold acids, the former with red, the latter with green colour. In excess of am- 
 monia, they both dissolve slowly with peach-blossom colour, the greyish- blue pre- 
 cipitate, however, the more abundantly of the two. 
 
 The properties of the hydrates, precipitated by ammonia, are affected to a con- 
 siderable extent by the concentration and temperature of the chromic solution and 
 of the ammonia, by the way in which they are mixed, &c. ; and the results obtained 
 by different experimenters regarding the constitution and properties of these hydrates 
 are by no means accordant. L. Schaffner (Ann. Ch. Pharm. li. 168) describes three 
 modifications of chromic hydrate : the first obtained by boiling chromic chloride with 
 excess of potash, and containing, according to Ordway (Sill. Am. J. [2] xxvi. 197), 
 Cr 4 3 .4H 2 0, or H 8 Cr 4 7 ; the second, by treating the chloride with sufficient potash to 
 redissolve the precipitate first formed, and neutralising the excess of alkali with hydro- 
 chloric acid ; the third, by precipitating a solution of a chromic salt with excess of 
 ammonia : the dried precipitate thus obtained is, according to Schaffner, Cr 4 3 .6H 2 0, 
 or H I2 Cr 4 9 . 
 
 The following results have been obtained by Lefort (J. Pharm. [3] xviii. 27). 
 When a chromic salt is treated with excess of caustic soda -solution, the precipitate 
 first formed redissolves with green colour if the original chromic salt was green or 
 red, with bluish-violet colour if the chromic salt was bluish- violet. The solutions, if 
 heated, deposit a gelatinous hydrate of fine green colour, containing Cr 4 3 .5H 2 O, or 
 IPCr 2 4 . It becomes hard and black when dry, and yields a dark green powder. 
 The same hydrate is obtained by pouring a chromic salt of either modification into 
 excess of the boiling alkali-solution. 
 
 Another green hydrate, Cr 4 3 .6H 2 0, or H' 2 Cr 4 9 , is deposited when the solution of 
 chromic oxide in excess of alkali is left to itself. It exhibits the same properties as 
 the preceding (Lefort). According to Fremy, these hydrates contain 8 and 9 aq. re- 
 spectively. 
 
 A hydrate containing Cr 4 3 .7H 2 0, or H 7 Cr 2 5 , is obtained when a solution of violet 
 chrome-alum is poured into excess of ammonia ; the precipitated oxide then turns red 
 and redissolves, and, on heating the ammoniacal solution to a temperature not exceed- 
 ing 50 C., a greyish-green pulverulent precipitate is formed, having the composition 
 just stated, and dissolving in acids with violet colour. (Lefort.) 
 
 d. Cr 4 3 .9H 2 0, or HWO 6 . This hydrate is deposited as a violet powder when the 
 ammoniacal-solution of chrome-alum is left to evaporate in the air or over oil of vitriol. 
 "When dry, it forms a greyish- violet, very light powder ; when dissolved in acids, it yields 
 red salts. (Lefort.) 
 
 According to Fremy, this hydrate is obtained by precipitating a violet chromic salt 
 with ammonia, and drying the precipitate in vacuo. It dissolves in acetic acid, am- 
 monia, and dilute potash-ley. Its properties are liable to considerable alteration from 
 apparently trifling circumstances ; thus, by the action of boiling water, or by prolonged 
 contact with cold water, by the action of concentrated saline solutions, by desiccation 
 for several days in the air or in vacuo, and trituration, it is rendered insoluble in 
 liquids in which it was previously soluble. Fremy is of opinion that these alterations 
 result from an allotropic modification of the chromic oxide, and not from loss of water, 
 lie applies the term chromic oxide to the oxide which has been rendered insoluble 
 in acetic acid, potash, and ammonia in the manner just mentioned, and metachromic 
 oxide to that oxide which is soluble in these reagents, and is precipitated by am- 
 monia from a violet chromic salt. 
 
 3 p 3 
 
950 CHROMIUM: OXIDES. 
 
 A chromic hydrate, much used as a pigment, is the emerald-green of Patmetier, 
 Cr 4 O s .2H 2 = H 4 Cr'0 5 . It is prepared by melting in a crucible a mixture of equiva- 
 lent quantities of boric anhydride and acid chromate of potassium, whereby chromic 
 borate and borate of potassium are obtained, and treating the fused mass with water, 
 which resolves the chromic borate into boric acid and chromic hydrate. By washing 
 this hydrate and finely triturating it, a brilliant green powder is obtained. (Guignet, 
 Kep. Chim. app. 1859, p. 158.) 
 
 Arnandon (ibid. 201), by acting on acid chromate of potassium with phosphate of 
 ammonium, likewise obtained a very fine green pigment, which appeared to be chiefly 
 a chromic hydrate containing phosphoric acid. 
 
 For further details respecting the modifications of chromic hydrate, see Handw, d. 
 Chem. 2" Aufl. ii. [2] 1221. 
 
 Chromic Salts. The salts obtained by dissolving chromic oxide or hydrate in 
 acids, correspond in composition to the oxide itself, containing, that is to say, 3 at. 
 of monatomic acid radicle to 2 at. of chromium, or 3 at. of a diatomic acid radicl? to 
 4 at. chromium, e. g. the nitrate Cr 2 (NO 3 ) 3 , the sulphate Cr 4 (S0 4 ) 8 . The most definite 
 are the double sulphates, called chrome-alums, consisting of 1 at. chromic sulphate with 
 1 at. sulphate of an alkali-metal and 12 at, water, corresponding in composition to 
 common alum, and crystallising in the same form, e. g. potassio- chromic sulphate, 
 
 K 2 S0 4 .Cr 4 (S0 4 ) s + 12H 2 0, or KCr 2 (SO') 2 + 6H*0 = K,Cr 2 
 
 Chromic salts exhibit two modifications, the green, and the red, or violet, which 
 pass easily one into the other. Thus, a solution of chrome-alum prepared in the cold 
 lias a violet colour, which changes to green on heating the solution, but reappeai'S after 
 it has been left to itself for some time. In malay chromic salts the nitrate, for example, 
 the change from green to violet takes place very quickly. The green solutions also 
 take a bluish tint when heated with nitric acid. The violet appears to be the normal 
 modification, inasmuch as the others always pass into it after a while ; and it is only 
 the violet solutions that yield crystallisable salts, the green solutions, when evaporated, 
 leaving green amorphous masses. 
 
 Schro'tter (Pogg. Ann. liii. 13) supposes that the change from the violet to the 
 green modification by heat, is the result of a loss of chemically combined water, which 
 is gradually resumed when the green solution is left at rest. Otto (Lehrbuch, 3 AufL 
 ii. 93) remarks, in opposition to this view, that a red solution of chrome-alum does 
 not turn green when mixed with strong sulphuric acid, provided rise of temperature 
 be prevented. 
 
 Low el (J. pr. Chem. xxxvii. 38) supposes that the different coloured solutions 
 contain different proportions of acid and base, the red solutions containing normal 
 chromic salts, such as Cr 4 (SO') 3 , or Cr 4 O 3 .3SO s , and the green solutions basic salts of 
 the form Cr'0 3 .2SO 3 . This view receives some support from an observation of 
 Krfiger (Pogg. Ann. Ixi. 218), that when a green solution of chrome-alum, obtained 
 by boiling the salt with a very small quantity of water, is mixed with alcohol, the 
 alcohol takes up a portion of the sulphuric acid, while the separated syrupy liquid 
 contains the salt K 2 O.Cr<0 3 .3SO*. This salt, when dissolved in water, does not return 
 to the violet modification unless a quantity of sulphuric acid be added to it sufficient 
 to reproduce the normal salt K 2 O.Cr 4 3 .4S0 3 . 
 
 Fremy attributes the change of the violet salts into green by the boiling of their 
 solutions, to a conversion of metachromic oxide into ordinary chromic oxide ; this, how- 
 ever, can scarcely be called an explanation. 
 
 For the behaviour of chromic salts with reagents see pp. 943, 944. 
 
 Chromites. Chromic oxide unites with protoxides, forming compounds of the form 
 M*O.Cr 4 0* or MCr'-'O 2 , which may be called chromites. The best known of these com- 
 pounds is chrome-iron ore, in which, however, part of the chromium is usually replaced 
 by aluminium and sometimes by iron. Lime, magnesia, and oxide of zinc, when they 
 exist in solution with chromium, are sometimes precipitated by alkalis, when, if the 
 chromium were not present, they would remain dissolved ; thus, a solution of chrome- 
 alum mixed with chloride of calcium yields with ammonia a green precipitate, con- 
 sisting of 2Ca 2 O.Cr'0 3 . On the other hand, bases which would otherwise be pre- 
 cipitated are sometimes retained in solution through the medium of chromic oxide ; this 
 is often the case with manganous and ferric oxide. In presence of 80 per cent, ferric 
 oxide, however, chromic oxide is completely precipitated. These circumstances require 
 to be carefully borne in mind in analysis. 
 
 Compounds of Chromic Oxide with Ammonia. (Fre'my, Ann. Ch. Pharm. 
 ex. 226.) Chromic hydrate is slightly soluble in ammonia, and, under certain circum- 
 stances, takes up the elements of ammonia, forming peculiar metallic bases, designated 
 by Premy as amido-chromium compounds. 
 
 Chromic hydrate which has been subjected to the action of boiling water does not 
 
CHROMIUM : OXIDES. 951 
 
 act upon ammonia; but metachromic hydrate (p. 950), in contact with ammonia, 
 acquires a violet colour, and forms the compound containing 2NH 3 .Cr 4 3 , which gives 
 off the whole of its ammonia when heated. 
 
 Ammoniacal salts do not act on metachromic hydrate by themselves ; but if am- 
 monia is likewise present, the hydrate dissolves, forming compounds of a beautiful 
 violet colour, which may be obtained in definite form by precipitating with alcohol and 
 rapid drying in vacuo. The compound formed with ammonia and chloride of ammo- 
 nium dissolves in water with deep violet-red colour. The solution has a scarcely 
 perceptible alkaline reaction, and does not yield any precipitate with nitrate of silver ; 
 but if it be heated to the boiling point, ammonia is given off, chromic hydrate sepa- 
 rates out, and the remaining liquid then gives a copious precipitate with nitrate of 
 silver. The products of the decomposition are 4NH 4 C1, 8NH 3 , 3Cr 4 3 , and H 2 0. 
 
 If the solution of the amido-chromium compound be left to itself for a while, it decom- 
 poses, ammonia being evolved, sal-ammoniac being reproduced, and an insoluble violet 
 body being formed, which separates in round, transparent, iridescent granules. This 
 body likewise contains the elements of chromic oxide and ammonia. It is completely 
 decomposed by boiling water, the products of decomposition being in the ratio of 
 Cr 4 8 : 2NH 3 : 12B?0. Acids convert it into a basic compound, Cr 4 8 .8NH 3 , called 
 roseo-chromammonia. With sulphuric acid the reaction is : 
 
 4(Cr 4 3 .2NH 3 ) + 12H 2 SO* = (Cr 4 3 .8NH s ).3S0 3 + 3(Cr 4 8 .3SO s ) + 12H 2 O. 
 
 Sulphate of roseo- Chromic 
 
 chromammonia. sulphate. 
 
 Koseo-chromammonia may likewise be obtained by the action of strong acids in the 
 eold on the soluble amido-chromium compounds precipitated by alcohol from the rose- 
 eoloured liquids which are produced by the joint action of ammonia and ammonium-salts 
 on metachromic hydrate. The salts of this base have nearly a wine-red colour ; the 
 hydrochlorate crystallises in regular octahedrons, and forms crystallisable double salts 
 with mercuric and platinic chlorides. Pure water decomposes it into two new salts, 
 one crystallising in right rhombic prisms, the other remaining in solution. The bases 
 of these two salts appear to differ from each other, and likewise from that of the hydro- 
 chlorate from which they were produced. (Fremy.) 
 
 A basic compound containing Cr 2 (CNS) s .(NH 4 ) 2 is obtained, by adding acid chro- 
 mate of potassium to fused sulphocyanate of ammonium. (Mori and, Chem. Soc. Qu. 
 J. xiii. 252.)' (See SULPHOCYANATKS.) 
 
 BROWN OXIDES OF CHROMIUM. CHROMA.TES or CHROMIUM. These names 
 are applied to certain oxides intermediate between the sesqui- and tri-oxides of chro- 
 mium. They are obtained by gently heating chromic nitrate ; by partial reduction of 
 chromic anhydride with alcohol, sulphurous acid, nitric oxide, or ferrous sulphate ; 
 also by boiling a solution of chromate of ammonium ; by digesting chromic acid with 
 excess of chromic oxide ; by heating chromic anhydride above 250 C. ; and by keeping 
 chromic oxide for some time, at 200 C., in contact with the air. A solution of acid 
 chromate of potassium, mixed with ammonia or with alcohol, likewise deposits a brown 
 sediment when exposed to sunlight, but not in the dark. 
 
 These brown compounds, when heated, first give off water, if they are hydrated, and 
 at higher temperatures are reduced to chromic oxide ; they dissolve in acids, forming 
 brown solutions, from which they are precipitated by ammonia without alteration. 
 They give off chlorine when heated with hydrochloric acid. Alkalis separate chromic 
 acid from them. 
 
 The brown oxides, obtained by different processes, exhibit considerable diversity of 
 composition, and it is not exactly known whether they are distinct oxides of chromium 
 or compounds of the sesqui- and tri-oxides. The compound obtained by heating 
 chromic hydrate in contact with the air, which has the composition CrO, or Cr 4 O s .Cr 2 3 , 
 is regarded by Kriiger as a peroxide of chromium, CrO, because, when heated with 
 sulphuric acid and chloride of sodium, it gives off only chlorine and no chlorochromic 
 anhydride, as all chromates do. A precipitate of the same composition is formed, ac- 
 cording to Berzelius, on mixing neutral solutions of chromic chloride and chromate of po- 
 tassium. The precipitate thrown down by ammonia from a solution of chromic sulphate 
 mixed with acid chromate of potassium, likewise gives off nothing but chlorine when 
 similarly treated ; according to Vogel, it is 2CrO.H 2 0. The black substance obtained 
 by heating chromic anhydride to 200 C. is, according to Traube, normal chromate of 
 chromium, Cr'0 8 .3Cr 2 8 . It becomes soluble by boiling in water, imparting to the 
 water, first a yellowish, then a deep brown colour. 
 
 The precipitate formed on mixing the solutions of chrome-alum and neutral chromate 
 of potassium has, when dried at 100 C., the composition 3Cr 4 3 .2Cr 2 3 .9H 2 O. The 
 oxide obtained by reducing chromic anhydride with alcohol, has, according to Traube, 
 the same composition. It is insoluble in water ; dissolves in hydrochloric acid with 
 
 3 P 4 
 
952 CHROMIUM: OXIDES. 
 
 yellow, in nitric and in hot dilute sulphuric acid with brown colour. The solutions 
 yield with ammonia a precipitate of sesquioxide, while chromic acid remains in solu- 
 tion. Potash quickly resolves it into chromic oxide and chromic acid. 
 
 Chromic hydrate digested with excess of chromic acid, yields a dark brown solution, 
 which dries up to a residue soluble in alcohol, and containing, according to Maus, 
 Cr 4 3 .4Cr 2 3 , or Cr'O*. (Handw. d. Chem. 2'" Aufl. ii. [2] 1236.)* 
 
 TRIOXIDE OF CHROMIUM. CHROMIC ANHYDRIDE. Anhydrous Chromic 
 Acid. Ci^O 3 . This oxide may be regarded as a constituent of the chromates, the 
 formula of a neutral chromate being MCrO 8 , or M 2 O.Cr 2 3 . It is obtained in the free 
 state: 
 
 a. By decomposing trifluoride of chromium with a s;naU quantity of water. The 
 vapour of the trifluoride, evolved by distilling chromate of lead and fluor spar with 
 fuming sulphuric acid, is passed into a large platinum crucible, slightly moistened on 
 the inside and closed with moist paper. The trifluoride is then decomposed by the 
 aqueous vapour, with which the air in the crucible is charged, into hydrofluoric acid 
 and beautiful red needles of chromic anhydride, which fill the crucible. 
 
 b. By decomposing a chromate with sulphuric acid. Chromic acid is easily prepared 
 by pouring 1 vol. of a saturated solution of acid chromate of potassium in a thin stream 
 into H vol. strong sulphuric acid, stirring all the while. As the liquid cools, chromic 
 anhydride crystallises from it in splendid crimson needles often an inch long. The 
 mother-liquor is decanted, and the crystals are drained on a porous tile till they are 
 nearly dry, and then purified by recrystallisation. For many purposes for which chromic 
 acid is used, the presence of a certain quantity of sulphuric acid is not objectionable, 
 w> that the purification may be dispensed with. 
 
 Bolley (Ann. Ch. Pharm. Ivi. 113) prepares chromic anhydride by dissolving a 
 weighed quantity of acid chromate of potassium in a small quantity of boiling water, 
 and adding to the hot solution the exact quantity of sulphuric acid required to form 
 acid sulphate of potassium. The mixture when left to cool, solidifies for the most 
 part into a red granuUir mass consisting of acid sulphate of potassium with adhering 
 chromic anhydride. The mixture is stirred to cause the granular mass to subside ; the 
 solution is decanted ; and the residual acid sulphate is washed several times with cold 
 water. There then remains an orange-coloured sulphate of potassium with very little 
 chromic acid, the greater part of that acid being contained in the united solutions. 
 The separation thus effected depends upon the circumstance that Etcid sulphate of po- 
 tassium, which dissolves very freely in boiling water (2 pts. of the salt to 1 pt. of 
 water), is but sparingly soluble at ordinary temperatures, and cold water removes sul- 
 phuric acid from it with scarcely any potash, leaving neutral sulphate of potassium, 
 while the chromic acid dissolves in the cold water. The solution of chromic acid con- 
 taining only a small quantity of acid sulphate of potassium is then further concen- 
 trated, and the chromic anhydride is precipitated by adding about an equal volume of 
 strong sulphuric acid, which throws it down free from any trace of acid sulphate. 
 
 Chromic anhydride may also be prepared by decomposing chromate of lead with 
 strong sulphuric acid, diluting with water after twenty-four hours, to precipitate sul- 
 phate of lead, then filtering and evaporating to the crystallising point, or by decompos- 
 ing chromate of barium with strong nitric acid, filtering the liquid from the resulting 
 nitrate of barium, which is insoluble in the strong acid, and heating the filtrate till 
 the excess of nitric acid is expelled, and crystallising as above. 
 
 Pure chromic anhydride forms either a red powder, a red loose woolly mass, or 
 scarlet crystals. It deliquesces in damp air and dissolves in a small quantity of water, 
 forming a dark brown liquid having a sour astringent, taste and yellow or brownish 
 yellow on dilution. The solution contains chromic acid, but when evaporated it yields 
 the anhydride : indeed chromic acid is not known in the solid state. 
 
 Chromic anhydride melts at 190 C., and begins to decompose at 250, giving off 
 oxygen and leaving a brown oxide or chromate of chromium, which, when further 
 heated, is reduced to sesquioxide. Chromic anhydride is a powerful oxidising agent, 
 being quickly reduced to sesquioxide of chromium by sulphydric acid, sine, arsenious 
 acid, tartar-fa acid, sitf/ar, ak-ohol, and various other organic bodies, especially when 
 heated. With sulphy'dric acid it forms water and sets sulphur free : 2Cr 2 3 + 3H-S = 
 Cr'O 3 + 3H*O + S 3 ; with hydrochloric acid it yields sesquichloride of chromium, 
 water, and free chlorine : Cr 2 3 + 6HC1 = Cr 2 Cl 3 + 3H 2 + Cl 3 . Sulphurous acid 
 added to a solution of chromic acid or a chromate throws down a brown chromate 
 of chromium, consisting of Cr 4 3 .Cr 2 3 or CrO. A few drops of anhydrous 
 alcohol poured upon chromic anhydride instantly reduce it to sesquioxide, the 
 alcohol sometimes taking fire. A similar reduction attended with incandescence 
 
 * From recent experiments by Scorer and Eliot (Proc. Amer. Acad. v. 192), it appears that there is 
 but OIK- definite oxide of chromium intermediate between Cr 4 O 3 and Cr 2 O 3 , viz. CrO or Cr 4 O 3 .Cr 2 O 3 . 
 The authors have likewise obtained the analogous compounds Al 1 O 3 .Cr 2 O 3 , JVCP.Cr-O 1 , Mn<O 8 .Cr 2 O 3 . 
 
CHROMIUM: OXYCHLORIDES. 953 
 
 takes place when a small quantity of the anhydride is introduced into an atmosphere 
 of alcohol vapour, or of alcohol or ether vapour mixed with sulphide of carbon. Dry 
 ammonia etas suddenly directed upon perfectly dry chromic anhydride, renders it in- 
 candescent and converts it into chromic oxide, while nitrogen and aqueous vapour are 
 given off. Aqueous chromic acid bleaches vegetable colours. 
 
 Chromic acid in the free state is sometimes used practically as an oxidisng agent, 
 but more frequently a mixture of sulphuric acid and chromate of potassium, which 
 yields it. 
 
 When crystallised chromic anhydride is added to strong sulphuric acid as long as it 
 dissolves, an ochre-yellow, pasty, very hygroscopic substance is formed, containing, 
 according to Boll ey (Ann. Ch. Pharm. Ivi. 113), H 2 S0 4 .Cr 2 3 . When exposed to the 
 air, it quickly turns red from separation of chromic anhydride. Schrotter (Pogg. 
 Ann. lix. 616) obtained in like manner a yellow-brown sediment, which he represents 
 approximately by the formula Cr*0 3 .3S0 3 . 
 
 PERCHROMIC ACID. HCr 2 4 or H 2 O.Cr 4 7 ? When peroxide of hydrogen dis- 
 solved in water is mixed with a solution of chromic acid, the liquid assumes a deep 
 indigo-blue colour, but often loses this colour very rapidly, giving off oxygen at the 
 same time. The same blue colour is produced on adding a mixture of aqueous per- 
 oxide of hydrogen and sulphuric or hydrochloric acid to acid chromate of potassium ; 
 but in a very short time oxygen is evolved, and chrome^alum is left in solution. For 
 each atom of acid chromate of potassium, K 2 0.2Cr 2 3 , 4 at. of oxygen are evolved, 
 provided an excess of peroxide of hydrogen be present. We may, therefore, suppose 
 that perchromic acid, HCr 2 4 , is first formed by the union of HO with C^O', and 
 afterwards resolved into oxygen and chromic hydrate, 2HCr 2 4 H 2 O.Cr 4 3 + O 4 . 
 With ether, perchromic anhydride forms a more stable solution than with water. The 
 ethereal solution, which has a deep blue colour, may be obtained by treating peroxide 
 of barium with hydrochloric or nitric acid, pouring ether on the liquid, gradually add- 
 ing a solution of acid chromate of potassium, and agitating. Perchromic acid is de- 
 composed by aqueous alkalis, with formation of a chromate and evolution of oxygen ; 
 but ammonia and certain organic bases dissolved in ether and added to the ethereal 
 solution of the acid, form stable compounds, from which stronger acids separate the 
 blue acid. The most stable of these compounds is the quinine-salt, which is soluble in 
 alcohol, insoluble in ether, and may be dried without decomposition. (Barreswil, 
 Compt. rend. xvi. 1085.) 
 
 The recent investigations of A s ch of (Inaugural-Dissertation iiber die Uebermangan- 
 s'dure und Ucberchromsaure, Berlin, 1861) tend strongly to confirm the formula Cr'O 7 
 for hypothetical perchromic anhydride. He also finds that when the deep blue ethereal 
 solution of perchromic acid is shaken up with such a quantity of very dilute aqueous 
 potash, that the ethereal layer shall still exhibit a faint blue tint, the aqueous, per- 
 fectly neutral liquid below exhibits a peculiar deep bluish- violet tint, which is tolerably 
 stable ; but if more potash be added, the colour changes to the light yellow of neutral 
 chromate of potassium, while bubbles of oxygen are given off. Hence it appears that 
 the blue colour belongs to the free acid, the violet to its salts. 
 
 According to Storer (J. pr. Chem. Ixxxi. 44) the colouring power of perchromic 
 acid is so great, that when a solution of 1 pt. acid chromate of potassium in 30,000 to 
 40,000 pts. water is shaken up with ether containing peroxide of hydrogen, the ether 
 acquires a perceptible blue tint ; he therefore recommends this reaction as a very deli- 
 cate test for chromic acid. Schonbein (ibid. Ixxix. 65) applies it as a test for per- 
 oxide of hydrogen. 
 
 CHROMIUM, OXYCHX.ORi:DES OP. Four of these compounds are known, 
 three of which may be regarded as compounds of sesquioxideand sesquichloride of chro- 
 mium, and the fourth (the so-called chlorochromic acid"), as a compound of the tri- 
 chloride and trioxide. They may also be regarded as derived from the trichloride or 
 sesquichloride by the substitution of oxygen for part of the chlorine. 
 
 a. Compounds of Sesquichloride and Scsquio&ide of Chromium. These compounds, 
 of which three have been distinguished, are obtained by evaporating the green solu- 
 tion of the sesquichloride, and heating the residue to different temperatures. By dry- 
 ing at 120 C. a reddish tumefied mass is left, containing 8Cr 2 CP.Cr 4 O s + 24H 2 0, or 
 Cr 2 "Cl- 4 3 + 24H 2 0. 
 
 By drying at 150 C., with constant stirring, a greyish red deliquescent powder is ob- 
 tained, consisting of 4Cr 2 Cl 3 .Cr 4 3 + 8H 2 = 3Cr 4 Cl 4 O + 8H 2 0, or, according to Peligot, 
 2(CrOCl.HCl) + H 2 0. If this compound be heated to redness, it becomes partially 
 insoluble in water, and the undissolved portion consists of Cr 2 Cl 3 .Cr 4 3 , or Cr 2 OCl. it- 
 is greyish-red by daylight, green by lamplight, like neutral chromic sulphate. By 
 prolonged ignition in contact with the air, it is completely converted into sesquioxide. 
 (Mo berg.) 
 
954 CHROMIUM: OXYGEN- SALTS SULPHIDE. 
 
 Peligot (J. pr. Chem. xxxvii. 476) obtained the last mentioned oxychloride by 
 precipitating a green solution of chromic chloride with baryta, evaporating the filtrate 
 to dryness, treating the residue with alcohol, and evaporating in vacuo, as a green de- 
 liquescent mass containing 20^001 H- 3H 2 O. The same oxychloride is obtained by 
 boiling the green solution of the chloride with chromic hydrate, or by prolonged boil- 
 ing of dilute hydrochloric acid with excess of chromic hydrate. 
 
 b. Chlorochromic Anhydride, Chlorochromic Acid. CrOCl, or CrCP.Cr'O 3 . 
 This compound, discovered by Berzelius, is produced by distilling any anhydrous metallic 
 chloride with an anhydrous chromate and strong sulphuric acid ; its formation affords 
 a useful test for the presence of chlorides (p. 903). To prepare it, 10 pts. of decrepi- 
 tated chloride of sodium are fused with 16*9 pts. of neutral chromate of potassium, and 
 the fused mass, after being broken into lumps, is distilled in a tubulated retort with 
 30 pts. of strong sulphuric acid, or better with the fuming acid. A brisk action imme- 
 diately takes place, and the Chlorochromic anhydride quickly distils over, without appli- 
 cation of heat ; it must be collected in a dry receiver kept at a low temperature. The 
 distillate obtained by heating the mixture towards the end of the process, is likely to 
 be contaminated with chromic and sulphuric acids (Wohler, Pogg. Ann. xxxiii. 343). 
 Another and easy mode of preparation is to distil in a small retort a dry mixture of' 
 chromic anhydride and ferric chloride. (Geuther, Ann. Ch. Pharm. cvi. 239.) 
 
 Chlorochromic anhydride is a mobile liquid of a splendid blood-red colour by trans- 
 mitted light, nearly black by reflected light. It has a density of 1 '7 1, and boils at 1 1 8 C. 
 When exposed to the air, it diffuses a yellowish-red vapour of specific gravity 5-48. It 
 attacks mercury rapidly, detonates with phosphorus, sets fire to sulphur, alcohol, oil of 
 turpentine, and other inflammable bodies, and decomposes sulphydric acid, with emission 
 of light. In ammonia gas, it solidifies with brilliant incandescence, forming a dark brown 
 mass, which remains red-hot for some time. If more ammonia gas be passed over the 
 ignited residue, it changes to a black powder, which, according to Schrotter, is nitride 
 of chromium. When Chlorochromic anhydride is distilled with pentachloride of phos- 
 phorus, chlorine-gas is evolved, and a small quantity of sesquichloride of chromium is 
 formed, but the greater part of the Chlorochromic anhydride distils without alteration. 
 It dissolves iodine and forms a solid brown mass with chlorine. When dropped into 
 water, it remains unaltered for a few seconds, but is afterwards decomposed, with vio- 
 lent ebullition, into chromic and hydrochloric acids. 
 
 Vapour of Chlorochromic anhydride passed through a glass tube heated to low red- 
 ness is decomposed, with formation of crystalline chromic oxide (p. 948). 
 
 The compound described at page 938 as chromochloride of potassium, may be re- 
 garded as a compound of Chlorochromic anhydride with neutral chromate of potas- 
 sium, KCr0 2 .CrOCL 
 
 CHROMIUM, OXYGEN-SAIiTS OF. See CIIROMOUS and CHROMIC OXIDES 
 (pp. 947, 950) ; also the several ACIDS. 
 
 CHROMIUM, PHOSPHIDE OP. Cr 2 P. Formed when chromic phosphate is 
 strongly ignited with charcoal, or when sesquichloride of chromium is heated in phos- 
 phoretted hydrogen gas. The product obtained by the first process is light grey, with 
 faint lustre, and loosely coherent. The phosphide prepared from crystallised chromic 
 chloride forms crystalline scales, like those of the chloride itself ; it is black, dissolves 
 but slightly in nitric, nitromuriatic or hydrofluoric acid, oxidises slowly when heated 
 in the air ; when it is heated with hydrate of potassium, hydrogen is evolved, and 
 chromate of potassium very slowly formed. (H. Eose, Pogg. Ann. xxxiv. 333.) 
 
 CHROMIUM, SULPHIDES OP. The protosulphide, Cr 2 S, is said to be ob- 
 tained, mixed with chromic oxide, by heating chromic sulphate in dry oxygen gas 
 (Traube). According to Moberg, protochloride of chromium gives a black precipitate 
 with sulphide of ammonium. 
 
 The scsquisulphide, Cr 4 S 3 , is produced by passing vapour of sulphide of carbon over 
 the white-hot sesquioxide ; by passing dry sulphydric acid gas over chromic anhydride, 
 oxide, or chloride, heated to bright redness ; by heating chromic hydrate with sulphur 
 in vacuo ; or by melting chromic oxide with pentasulphide of potassium at a very high 
 temperature. It cannot be obtained by precipitation, the precipitate formed by sul- 
 phide of ammonium in solutions of chromic salts, consisting, not of sulphide, but of 
 hydrate. 
 
 Sesquisulphide of chromium is dark grey or black, according to the mode of prepara- 
 tion, sometimes shining and crystalline, without metallic appearance, but acquiring an 
 iron-grey metallic lustre by pressure or trituration. When heated in the air, it burns to 
 sesquioxide. Heated in chlorine gas, it yields chloride of sulphur and sesquichloride of 
 chromium (BerzeliusX According to H. Eose, on the other hand, chlorine scarcely 
 acts upon it, even at high temperatures. Heated with nitre, it yields sulphate and 
 chromate of potassium. It appears to unite with the acid sulphides, forming sulphur- 
 salts. (Gm. iv. 121.) 
 
CHROMOTARTARIC ACID CHRYSAMMIC ACID. 955 
 
 A sulphide containing Ci^S 3 is obtained by heating chromic sulphate in hydrogen 
 gas. Sulphurous anhydride is then evolved and sulphuric acid is formed, together 
 with a blackish-brown, extremely pyrophoric powder, which burns in the air to chromic 
 oxide and sulphurous anhydride. (Kopp, Compt. rend. xix. 1156.) 
 
 CHROMOTARTARXC ACID. When tartaric acid in powder is gradually 
 added to a warm aqueous solution of acid chromate of potassium, as long as carbonic 
 acid is evolved, a green solution is formed, which yields by evaporation a vitreous 
 mass, very soluble in water, precipitated by alcohol, and containing, according to 
 Malaguti, C 4 H 4 K(Cr 2 0)'0 6 + 7aq. The solution of this salt yields with acetate of 
 lead, a bluish-green precipitate, which, when decomposed by sulphuretted hydrogen, 
 yields tartrate of chromium and hydrogen, or chro mo-tar taric acid, CEEW(Ol*Oy0*. 
 (Berlin, Gerhard? s Traite, ii. 31.) 
 
 CHRORXUXiS. Syn. with CHLOROPHYLL. 
 
 CHRTTZGDlisr E. A product of the decomposition of chrysanimic acid by sulphuric 
 acid. (See CHKYSAMMIC Aero.) 
 
 CHSYSAIttXDE. C'H 3 (N0 2 ) 2 NO = N.H 2 .C 7 H(N0 2 ) 2 0. A compound formed 
 by boiling chrysammic acid with aqueous ammonia. The acid dissolves ; the liquid 
 acquires a deep purple tint, and on cooling deposits chrysamide in needles, which are 
 reddish-brown by transmitted, and metallic green by reflected light. Its solution, 
 treated with dilute acids, does not yield a precipitate of chrysammic acid. With 
 chloride of barium and ammonia, it forms a precipitate of chrysamidate of barium. 
 
 According to the formula C 7 H 3 (N0 2 ) 2 NO, which is that proposed by G-erhardt 
 (Traite, iv. 253), chrysamide, like amides in general, differs from chrysammate of 
 ammonium, C 7 H(NH 4 )(NO-)0*, by 1 at. H 2 0. This formula requires 40 per cent. C, 
 2-4 H, and 20'1 N, whereas the analysis of chrysamide by Schunck and Mulder, gives 
 37-6 38-8 C, 1-85 2-35 H, and 18-2 19'9 N ; but it is probable that the chrysamide 
 analysed was partly converted during the preparation into chrysamidic acid by addi- 
 tion of water, or rather perhaps, that the conversion of the chrysammate of ammonium 
 into chrysamide was not quite complete. 
 
 CHRYSA1VXXDXC ACXX>. Ammonio-chrysammic acid. C 7 H 5 N 3 8 = NH 8 . 
 C 7 H V? (N0 2 ) 2 8 . This acid, which is isomeric with chrysammate of ammonium, is pro- 
 duced by adding dilute sulphuric or hydrochloric acid to a boiling aqueous solution of 
 
 precipitated by 
 
 with potash. It is not altered by dilute acids. Strong sulphuric and boiling nitric 
 
 acid partly convert it into chrysammic acid, with formation of ammoniacal salts. 
 
 The chrys ami dates, C 7 H 4 MN 3 6 , have the composition of double chrysammates 
 of ammonium and another base, C 7 (NH 4 )MN'-'0 6 They resemble the chrysammates 
 in appearance, and in their property of detonating when heated ; but are distinguished 
 by giving off ammonia when treated with caustic potash. 
 
 Chrysamidate of potassium crystallises in small needles, having a green metallic 
 lustre by reflected light. The barium-salt is a red crystalline precipitate. 
 
 CHRYSAXKMXC ACID. C 7 H 2 N 2 6 = C 7 H 2 (NO'0 2 2 . (Schunck. Ann. Ch. 
 Pharm. xxxix. 1; Ixv. 235. Mulder, ibid. Ixxiii. 339; Ixxii. 285. Laurent, 
 Compt, chim. 1850, p. 163. Kobiquet, J. Pharm. [3] x. 167, 241). This acid is 
 produced by the action of nitric acid upon aloes ; probably, also by the action of nitric 
 acid on aporetin. (De la Kue and Miiller, Chem. Soc. Qu. J. x. 298.) 
 
 reparation from aloes. 1 pt. of aloes is macerated with 8 pts. of nitric acid of 
 specific gravity 1-37 ; the mass is heated in a large basin till the first violent action 
 has subsided, afterwards in a retort till two-thirds of the nitric acid have been expelled ; 
 3 or 4 pts. more nitric acid and water are added to the residual liquid as long as a 
 precipitate continues to form ; and the precipitate, which consists of small shining scales, 
 is washed with cold water till the liquid no longer acquires a yellow, but a faint purple- 
 red colour. The resulting chrysammic acid, still containing aloetic acid, is triturated 
 with aqueous carbonate of potassium ; and the gelatinous mass, which is thereby 
 formed, with evolution of carbonic acid, is washed with cold water till the whole of 
 the carbonate of potassium is removed, then dissolved in boiling water, and the solu- 
 tion filtered ; as the liquid cools, the pure potassium-salt separates in golden-yellow 
 lamin?e. These crystals are dissolved in boiling water, decomposed by nitric acid, 
 and the chrysammic acid, which separates in the form of a yellow powder, is washed 
 with cold water till the nitric acid is completely removed, and the water is coloured 
 no longer yellow but light purple-red. In treating the chrysammic acid with carbo- 
 nate of potassium, an excess of the latter must be avoided as far as possible, because it 
 produces a decomposition and reddening of the salt, perhaps from admixture of aloetic 
 acid. 
 
956 CHRYSAMMIC ACID. 
 
 Chrysammic acid is a yellow powder, often light yellow or greenish yellow, and con- 
 sisting of small shining scales. It is sparingly soluble in cold, more easily in boiling 
 water. The solution has a deep purple colour, tastes bitter, and reddens litmus. It 
 dissolves easily in alcohol and ether ; also in nitric acid and in saline solutions. 
 
 The acid detonates violently when subjected to dry distillation, emitting a bright 
 but smoky flame, and diffusing an odour of bitter almonds, together with nitrous 
 vapours. Heated in chlorine gas, it gives off hydrochloric acid. Boiled with caustic 
 potash, it forms a brown solution from which acids throw down a dark brown precipi- 
 tate (Schunck' s aloeretic acid ; Mulder's chrysatic acid}, soluble in pure water, forming 
 soluble salts with the alkalis and earths, insoluble with lead and silver. If the potash 
 is very strong, ammonia is likewise evolved. Chrysammic acid is not attacked by 
 fuming nitric acid (Schunck). With strong sulphuric acid at the boiling heat, it 
 reacts violently, giving off copious red fumes containing carbonic anhydride, carbonic 
 oxide, sulphurous anhydride, and nitrous anhydride. At the same time a dark 
 violet-coloured substance is deposited (Mulder's chryiodine), soluble in potash and re- 
 precipitated by hydrochloric acid, as a gelatinous mass of the same colour. This pro- 
 duct appears to be only a mixture, for ammonia separates it into a soluble and an 
 insoluble portion. Sulphide of potassium mixed with caustic potash, transforms 
 chrysammic acid into hydrochrysamide : a similar blue substance (Mulder's chri/siud/u- 
 ammonium') is obtained by decomposing a warm ammoniacal solution of chrysammic 
 acid with sulphuretted hydrogen. Ammonia converts chrysammic acid into chrysamide. 
 The acid boiled with water and stannous chloride, forms a powder which has a deep 
 violet colour, is nearly insoluble in all solvents (C lt H l N' 2 O n .3SnO' z , according to 
 Mulder), gives off ammonia and assumes a fine blue colour when treated with potash, 
 and is decomposed by nitric acid, yielding aloetic and chrysammic acids. 
 
 The chrysammates mostly crystallise in small scales, and exhibit a gold-green 
 metallic lustre on the crystalline faces ; those which are amorphous, exhibit the same 
 lustre when rubbed with a hard body. They detonate violently when heated. They 
 are all sparingly soluble, even those of the alkali-metals. In solutions of acetates they 
 dissolve more easily than in water, but less when heated than in the cold. 
 
 Chrysammate of Ammonium changes rapidly into chrysamide. 
 
 Chrysammate of Barium, C 7 HBaN 2 6 + 2aq., is obtained as a vermilion-coloured 
 precipitate by mixing a solution of the potassium-salt with chloride of barium ; also by 
 prolonged boiling of chrysammic acid with chloride of barium. It is quite insoluble 
 in water. 
 
 Chrysammate of Cadmium is a dark purple precipitate. 
 
 Chrysammate of Calcium is a dark red insoluble powder, exhibiting traces of crystal- 
 lisation. 
 
 Chrysammate of Copper, C 7 HCuN 2 O a + # aq., is sparingly soluble in cold, more soluble 
 in boiling water, from which it separates in dark purple needles, exhibiting a golden 
 lustre by reflected light : its solution has a fine purple tint. 
 
 Chrysamrnate of Lead, C 7 HPbN 2 6 ? Brick-red insoluble powder, obtained by 
 precipitation. According to Schunck, it gives by analysis 34'2 per cent. Pb 2 0, the 
 formula requiring 3578. Mulder found in the precipitate formed with chrysammate 
 of potassium and neutral acetate of lead, 51*6 per cent. Pb"0, which corresponds to the 
 formula C 7 HPbN 2 6 .PbHO. 
 
 Chrysammate of Magnesium resembles the calcium-salt. 
 
 Chrysammate of Potassium, C 7 HKN 2 6 , crystallises in flat rhomboidal plates, which 
 exhibit very remarkable relations to polarised light. Light transmitted through one 
 of them, exhibits a reddish-yellow colour and becomes polarised in one plane ; but 
 if the crystal be pressed with the blade of a knife on a plate of glass, it spreads on 
 the glass like an amalgam, and a beam of light, transmitted through the thin film 
 thus formed, splits into two rays polarised in planes perpendicular to each other, one 
 having a carmine-red, the other a pale yellow colour. As the thickness of the film 
 increases, the colour of both rays approaches more and more to carmine-red. Still 
 more remarkable phenomena are exhibited by reflected light. An ordinary ray of 
 white light reflected perpendicularly from the face of a crystal or from a film, lias the 
 colour of virgin-gold, but as the incidence becomes more oblique, the colour becomes 
 less and less yellow, and at length passes into pale blue. The beam thus reflected is 
 composed of two rays oppositely polarised ; the one which is polarised in the plane of 
 reflection remains of a pale blue colour at all angles of incidence ; the other, polarised 
 at right angles to the plane of reflection, has a pale-yellow colour at small inclinations, 
 then changes to deep yellow, greenish-yellow, green, bluish-green, blue aud violet. 
 (Er easier, Gerhard fs"Traite, iv. 251.) 
 
 Chrysammate of potassium dissolves in 1250 pts. of cold water, easily in boiling 
 water; the solution has a fine red colour. 
 
 ii f Silvff. .Dark brown precipitate, quite insoluble in boiling water. 
 
CHRYSANILIC ACID CHRYSATRIC ACID. 957 
 
 Chrysammate of Sodium resembles the potassium-salt in appearance, and possesses 
 the same degree of solubility. 
 
 Chrysammate of Zinc crystallises in small dark red needles with gold-green reflection. 
 
 CHRVSAWTI2.IC ACID. This name was given byFritzsche to a bluish-rod 
 substance obtained by the action of potash upon indigo; according to Grerhardt 
 however (Traite, iii. 521), it is nothing but a mixture of isatin, white indigo, and 
 possibly other products. (See INDIGO.) 
 
 CHRTTSAKZSIC ACID. C 7 H 5 N 3 7 = C 7 H 3 (NO*) S (Ca hours, Ann. Ch. Phys. 
 [3] xxvii. 454). This acid, which is isomeric with trinitranisol, and may also be re- 
 garded as methyl-picric acid, C 6 H 2 (CIP)(N0 2 ) 3 0, is produced, together with di- and tri- 
 nitranisol, by the action of warm fuming nitric acid on anisic acid (p. 300). When 1 pt. 
 of perfectly dry anisic acid is very gently boiled for half or three-quarters of an hour 
 with 2| pts. of fuming nitric acid, and the somewhat thick liquid is mixed with 20 times 
 its bulk of water, a yellow oil separates out, which soon coagulates into a solid mass 
 consisting of chrysanisic acid mixed with di- and tri-nitranisol. This mixture, in the 
 form of fine powder, is washed on a filter with ammonia diluted with two or three 
 times its bulk of water, whereby the acid is extracted ; the ammoniacal liquid, after 
 being evaporated to one-third, yields on cooling brown needles of the ammonia-salt. 
 These crystals are dissolved in water ; the solution mixed with dilute hydrochloric 
 acid ; the separated yellow flakes are collected on a filter, repeatedly washed with cold 
 water, dried between bibulous paper, and dissolved in hot alcohol; and the scales 
 which crystallise from the solution on cooling are dried. 
 
 Chrysanisic acid forms small golden-yellow rhombic tables, nearly insoluble in cold 
 water, sparingly soluble in hot water, whence it crystallises on cooling. It is but slightly 
 soluble in cold alcohol, but dissolves so abundantly in hot alcohol, that the liquid 
 solidifies on cooling. It dissolves in ether, especially if hot, and crystallises in shining 
 laminae as the ether evaporates. The acid melts when cautiously heated, and solidifies 
 in the crystalline form on cooling; at a stronger heat, it emits a yellow vapour which 
 condenses in small crystalline scales having a strong lustre. 
 
 When boiled with strong nitric acid, it is converted into picric acid. Distilled with 
 aqueous chloride of lime, it yields chloropicrin. By boiling with potash, it is con- 
 verted into a brown substance. 
 
 Chrysanisate of Ammonium. The solution of the acid in dilute ammonia, evaporated 
 over the water-bath, yields on cooling, small brown needles having a strong lustre. 
 Finer crystals are obtained by spontaneous evaporation of the solution. 
 
 Chrysanisate of Potassium, C 7 H 4 K(N0 2 ) 3 0, is obtained by exactly saturating the acid 
 with potash. It is very soluble. 
 
 The ammonium-salt produces in solutions of zinc -salts, a pale yellow precipitate; with 
 nitrate of cobalt, a greenish yellow gelatinous precipitate ; with nitrate of lead, a 
 copious deposit of chrome-yellow flakes ; with ferric salts, a pale yellow ; with cupr/'c 
 salts, a greenish yellow, gelatinous precipitate ; and with mercuric chloride, yellowish- 
 red flakes, which in dilute solutions appear after a time only. 
 
 Chrysanisate of Silver, C 7 H 4 Ag(N0 2 ) 3 0. The ammonium-salt forms with nitrate 
 of silver, beautiful yellow flakes, which must be washed with water and dried in 
 vacuo. 
 
 Chrysanisate of Ethyl, C 7 H 4 (C 2 H 5 )(N0 2 ) 3 0, is obtained by saturating the alcoholic 
 solution of the acid with dry hydrochloric acid gas, gently boiling for some time, and 
 then adding water. The resulting precipitate is washed, first with ammoniacal, after- 
 wards with pure water, then dissolved in boiling alcohol, and the solution is left to cool. 
 It forms transparent crystalline laminae of a splendid golden-yellow colour, melting at 
 about 100 C. It is soluble in warm ether. 
 
 CHR^SAXTTHEl^lTZWr SEGET1T1VT. The ash of this plant has been analysed 
 byBangert (J. pr. Chem. Ixx. 85). The fresh plant yielded 1'61 percent., the plant 
 dried at 100 C, 8'52 per cent, ash (63'3 per cent, of which was soluble in .water). The 
 ash contained in 100 pts. : 24*86 K 2 0, 6'21 Na 2 O, 14-08 Ca 2 0, 6'96 Mg 2 0, trace of 
 manganese, 5'12 SO 3 , 12'36 CO 8 , 6*16 P 2 5 , 4'68 SiO 2 , 16'10 NaCl, with 3'06 sand and 
 charcoal. 
 
 CHSYSATRIC ACID. (Mulder, J. pr. Chem. xlviii. 16.) Aloerctic acid. 
 (Schunck, Ann. Ch. Pharm. Iv. 240.) An acid produced by heating chrysnmmic 
 acid with alkalis. Chrysammic acid heated with potash-ley dissolves, forming" a brown 
 solution, from which, according to Mulder, acetic acid does not precipitate anything; 
 according to Schunck, however, a brown precipitate is obtained. The solution of the 
 potassium-salt yields with acetate of lead, a brown precipitate containing, according 
 to Tonningen's analysis, 5871 per cent. Pb 2 0, 19'08 C, 078 H, and 5'51 N. With 
 chloride of barium, a precipitate is formed, containing 30-80 per cent. Ba 2 0, 28'03 C, and 
 T82 H. (Schunck). These analyses do not lead to any satisfactory formula. 
 
958 CHRYSENE CHRYSOPHANIC ACID. 
 
 CHRYSENE, wC 6 !! 4 . (Laurent, Ann. Ch. Phys. [2] Ixvi. 130.) A crystalline 
 hydrocarbon obtained, together with pyrene, by the dry distillation of fats, resins, ami 
 coal : it may be extracted from coal-tar by redistillation. The products which pass <>vrr 
 towards the end of the process, consist of a soft yellow or reddish mass, and a thick 
 oil containing crystalline scales. That which condenses in the neck of the retort is 
 chiefly chrysene, the pyrene passing for the most part into the receiver. By treating 
 the mass in the neck of the retort with ether, the pyrene and certain oily matters are 
 dissolved out, while the chrysene remains in the pulverulent state. 
 
 Pure chrysene has a fine yellow colour ; it is crystalline, destitute of taste and odour, 
 insoluble in water and alcohol, nearly insoluble in ether : oil of turpentine dissolves it 
 at the boiling heat, and deposits it on cooling in yellow crystalline flakes. It melts 
 at 230 235 C., and solidifies on cooling to a deep yellow mass composed of needles. 
 At a higher temperature, it distils with slight alteration. 
 
 Nitrochrysene, wC 6 IT(N0 2 ), produced by the action of strong boiling nitric acid on 
 chrysene, is a red powder, destitute of taste and odour, insoluble in water, nearly 
 insoluble in alcohol and ether. It is dissolved with brown colour by sulphuric acid, 
 partially also by alcoholic potash. When quickly heated in a closed tube, it melts 
 and decomposes with explosion. 
 
 CHRYSXarDXXr. A product of the decomposition of chrysammic acid by am- 
 monia. (Mulder, p. 956.) 
 
 CHRYSOBERYIi. Cymophane, ChrysopaL An aluminate of glucinum, APG10-, 
 or G1 2 0. A1 4 3 , generally containing 2 or 3 per cent, of iron. It is usually found in round 
 pieces about the size of a pea, but sometimes in eight-sided prisms with six-sided 
 summits, belonging to the trimetric system. Specific gravity 3 '5 37. Hardness 8 '5. 
 Lustre vitreous. Colour various shades of green. Streak uncoloured. Transparent or 
 translucent, sometimes with bluish opalescence internally. Fracture concho'idal, uneven. 
 It exhibits double refraction, and becomes electric by friction. It is infusible alone 
 before the blowpipe, and very difficult to fuse with borax or phosphorus-salt. With 
 carbonate of sodium, the surface is merely rendered dull. It is not acted upon by acids. 
 
 Chrysoberyl is found in Brazil and Ceylon, in rolled pebbles, in the alluvial deposit 
 of rivers ; and in granite at Haddaw, Connecticut, Greenfield, near Saratoga, New 
 York, and Orange Summit, Vermont. When transparent and of sufficient size, it is 
 cut into facets and forms a gem. 
 
 Crystals of chrysoberyl have been formed artificially by exposing a mixture of 
 alumina and glucina in the proper proportion, together with boracic acid as a flux, to 
 the heat of a pottery furnace for several days, till the boracic acid is completely vola- 
 tilised (Ebelmen, Ann. Ch. Phys. [3] xxii. 211; xxxiii. 34). [For the crystalline 
 form of the artificial chrysoberyl, see Jahresber. d. Chem. 1851, p. 765.] 
 
 A variety of chrysoberyl called Alexandrite, from the Ural, exhibits pleochroism, 
 viz. by perfectly white light, an orange-yellow colour in the direction of the longer 
 diagonal of the base, colombo-red along the shorter diagonal, and emerald-green along 
 the principal axis. (Haidinger, Pogg. Ann. Ixxvii, 228.) 
 
 CHRYSOCOXiItA. The Greek name for borax. Applied also to silicate of copper. 
 
 CHRYSOHARIKINZ:. Syn. with NlTKOHARMALINE (q. V.) 
 
 CHRYSOHDIET. C 7 H 22 O l ? A yellow colouring matter said to exist in very small 
 quantity in asparagus-berries. 
 
 CRHYSOX.EPXC ACID. Syn. with PICRIC ACID. 
 
 CHRYSOLITE. Peridotc, Olivin. A silicate of magnesium and iron,(Mg;Fe) 4 
 SiO 4 , occurring in basalt and lavas, in prismatic crystals of the trimetric system, also 
 massive and compact or granular ; colour olive and other shades of green. The term 
 Chrysolite includes the transparent crystals of paler colour, while Olivine (so-called 
 from the olive-green tint) is applied to imbedded masses or grains of inferior colour 
 and clearness. (See OLIVINE.) 
 
 CHRYSOlYIELATtfE. Syn. with PtEONAST. 
 
 CHRYSOPAXi. Syn. with CHBYSOBEBYL. 
 
 CHRYSOPHATJE. See ClJNTONITE. 
 
 CHRYSOPHANIC ACID. Chrysophane, Ehubarbaric acid, Rhubarbarin, Rhu- 
 barb-yellow, Rhcin, Rhcic acid, Rheumin, Rhaponticin, Rumicin, C 10 H 8 3 , or C 7 H'0 2 . 
 The yellow colouring principle of rhubarb and of the wall lichen (Parmelia parietina}. 
 It was first obtained in an impure state by Herberger, Bulk, and Brandes, afterwards 
 analysed by Rochleder and Heldt (Ann. Ch. Pharm. xlviii. 12), who extracted the 
 pure substance from the Parmelia; also by Doppin'g and Schlossberger (ibid. 1. 
 215), by De La Rue and Miiller (Chem. Soc. Qu. J. x. 298) and by Thann (Ann. 
 Ch. Pharm. cvii. 324), who obtained it from rhubarb. 
 
 Preparation from Parmelia parietina. The dried lichen is digested in the cold 
 
CHRYSOPHANIC ACID. 959 
 
 with alcoholic potash or ammonia ; the dark red infusion is filtered and mixed with 
 acetic acid ; the bulky yellow flocks thereby precipitated are washed with water and 
 redissolved in alcoholic potash, a certain quantity of resin then remaining undissolved ; 
 the liquid is again precipitated by hydrochloric acid ; and the precipitate, after wash- 
 ing and drying, is redissolved in a small quantity of boiling absolute alcohol. The 
 solution then deposits chrysophanic acid in the crystallised state. 
 
 From Rhubarb. Dulk prepared chrysophanic acid from rhubarb by exhausting the 
 root with alcoholic ammonia, precipitating with subacetate of lead, and decomposing 
 the precipitate, suspended in alcohol, with sulphuretted hydrogen. Schlossberger and 
 Popping exhaust the pulverised rhubarb with 80 per cent alcohol ; evaporate ; redis- 
 solve in a small quantity of alcohol ; add ether to the solution to precipitate certain 
 resinous matters ; evaporate the filtered solution to the crystallising point ; and purify 
 the chrysophanic acid thus obtained by repeated crystallisation from boiling absolute 
 alcohol. 
 
 De la Eue and Miiller find that chrysophanic acid may be extracted from rhubarb 
 with much greater facility by means of benzene or the light hydrocarbons obtained 
 from Burmese naphtha, these liquids dissolving it very readily, to the exclusion of the 
 greater part of the other constituents. The crushed root is first macerated in water, 
 which removes about 50 per cent, of soluble matter, then dried and treated with 
 benzene in a Mohr's displacement apparatus ; the greater part of the benzene is then 
 distilled off; the residue, which becomes nearly solid on cooling, is pressed between 
 blotting paper to remove the mother-liquor which contains erythroretiu and a neutral 
 fat ; the crude chrysophanic acid thus obtained is redissolved in hot benzene, which 
 leaves behind a reddish-yellow substance (e-modin), an additional quantity of which 
 separates as the solution cools ; and the chrysophanic acid, which afterwards crystallises 
 out, is further purified by recrystallisation from acetic acid, amylic alcohol, or common 
 alcohol. The residuary rhubarb, thrown away in pharmaceutical laboratories after the 
 preparation of the ordinary alcoholic tincture, may be advantageously used for the pre- 
 paration of chrysophanic acid by this process, inasmuch as it contains about 2 '6 per 
 cent, of that acid, which is but slightly soluble in alcohol, especially in the weak spirit 
 used in the preparation of the tincture. The dark coloured resinous sediment which 
 separates from Tinctura Ehei when left to itself, is also rich in chrysophanic acid, and 
 may be subjected to the same treatment. 
 
 Thann extracts the root of Eumcx obtusifolius with ether ; distils off the greater part 
 of the liquid ; washes the dark yellow-brown mass which separates on cooling with a 
 small quantity of ether ; dries it between bibulous paper ; boils the residue with 90 
 per cent, alcohol ; dissolves the dirty green granular mass which separates on cooling 
 with alcohol, and precipitates by water, repeating the solution and precipitation several 
 times ; purifies the product by treatment with alcoholic ammonia and acetic acid, as in 
 Rochleder and Heldt's process ; then crystallises it from alcohol, and lastly from ether 
 by slow evaporation. 
 
 Chrysophanic acid crystallises from benzene in six-sided tables (monoclinic), having 
 a pale yellow or orange-yellow colour ; from alcohol, amyl-alcohol, or glacial acetic 
 acid, in moss-like aggregates of laminar crystals. It is sparingly soluble in cold water ; 
 dissolves in 224 pts. of boiling alcohol of 86 per cent. ; in 1125 pts. of the same alcohol 
 at 30 C. It is soluble also in ether and in oil of turpentine, coal-naphtha, benzene, and 
 other hydrocarbons (vid. sup.) It melts without decomposition at 162 C. and soli- 
 difies in the crystalline form on cooling. 
 
 The formula of chrysophanic acid is not quite settled. The analyses by Rochleder 
 and Heldt, and by Schlossberger and Dopping, approach nearly to the formula 
 C 10 H 8 O 3 , while those by De la Rue and Muller, and by Thann, agree better with 
 C 7 H'0 2 . 
 
 Calculation. Rochleder Schlossberger DC la Rue Calculation. 
 
 C"'H H O 3 and Heldt. and Dopping. and Miiller. Thann. Ci?H'O 2 
 Carbon . . 68*12 68-03 68-12 6876 69'62 69-52 
 
 Hydrogen . 4-54 4'57 4'59 4-25 4'39 412 
 
 Oxygen. . 27'34 26-36 
 
 100-00 100-00 
 
 Chrysophanic acid subjected to dry distillation, partly sublimes, while another por- 
 tion becomes carbonised. Dilute nitric acid does not appear to act upon it, even at 
 the boiling heat,_ but the strong acid converts it into a red substance. Strong sulphuric 
 acid dissolves without decomposing it, and water precipitates it from the solution. 
 
 The acid dissolves in alkalis with fine deep purple colour : the reaction is very deli- 
 cate, so that a dilute solution of chrysophanic acid may be used as a test for alkalis. 
 Its solution in potash may be evaporated to drynoss without alteration ; but at a certain 
 degree of concentration, it deposits blue or violet flocks, which redissolve in water or 
 alcohol, forming red solutions. If the purple solution of the acid in moderately strong 
 
960 CHRYSOPRASE CHYLE. 
 
 potash, together with the flocculent precipitate, be mixed with grapo sugar and left <o 
 stand in a closed vessel, the alkali being in excess, the colour of the liquid gradually 
 changes to brownish -yellow, and the precipitate disappears : on subsequent exposure to 
 the air, the original colour and the precipitate are reproduced. Hydrate of potassium 
 at its melting point does not act on chrysophanic acid at first ; but if the heat be con- 
 tinued or increased, the liquid turns blue and decomposes, emitting an odour like that 
 of octylic alcohol. (De la Rue and Muller.) 
 
 With baryta and oxide of lead, chrysophanic acid forms very unstable compounds, 
 which are decomposed even by the carbonic acid in the air. Its alcoholic solution 
 forms with alcoholic subacetate of lead, a reddish-white precipitate, which changes to 
 rose-red by boiling with water ; no precipitate with neutral acetate of lead. The am- 
 moniacal solution of chrysophanic acid yields with neutral acetate of lead, a lilac ; with 
 alum, a beautiful rose-coloured precipitate. (Thann.) 
 
 CHRYSOPRASX:. An apple-green or leek-green variety of chalcedony, coloured 
 by nickel. 
 
 CHXrcSOPRASE EARTH. See PlMELITE. 
 
 CHRYSORETIN. A yellow resin obtained from senna-leaves by evaporating 
 the aqueous extract, treating the residue with alcohol, evaporating, dissolving in ether, 
 and again evaporating. It is a mixture of several substances, perhaps containing 
 chrysophanic acid, or a similar acid. (Bley and Diesel, Jahresber. 1848, p. 828.) 
 
 CHRYSORHAXMHVrXN. A yellow crystalline substance contained in Persian 
 berries or yellow berries (graines d? Avignon, Krautz-beereri), the fruit of Rhamnus 
 amygdalinus, R. oleo'idcs, R. saxatilis, <$rc., especially in the unripe state. According to 
 Kane (Ann. Ch. Phys. [3] viii. 380), it may be extracted from the berries by ether, in 
 which it is easily soluble. It is nearly insoluble in cold water, soluble in alcohol, and 
 contains 58*02 per cent, carbon, and 4*7 hydrogen, whence Kane deduces the formula 
 C^H^O". By boiling with alcohol or water, it is decomposed, yielding another 
 colouring matter, Xanthorhamnin, C 28 H 24 O n , which is soluble in water and alcohol, but 
 insoluble in ether. 
 
 G-ellatly (Edinb. N. Phil. J. vii. 252), by treating Persian berries with ether, ob- 
 tained neither chrysorhamnin nor any other characteristic substance ; but with alcohol, 
 he obtained a yellow substance crystallising in needles, which appeared to be xautho- 
 rhamnin. 
 
 According to Bolley (Chem. Soc. Qu. J. xiii. 327), Persian berries yield an abun- 
 dant extract when treated with crude ether (this may perhaps explain the difference 
 between the statements of Kane and G-ellatly) ; and on evaporating the ether, dissolving 
 the residue in alcohol, filtering, and evaporating with addition of water, stellate groups 
 of yellow needles are obtained, which are not altered by repeated solution, boiling, 
 and precipitation. They gave, by analysis of two specimens, 58*87 and 60*239 per cent, 
 carbon, 4*66 and 4'18 hydrogen. The crystals were somewhat soluble in pure ether, 
 sparingly in water, easily in alcohol. The solution gives with neutral acetate of 
 lead, a brick-red precipitate ; with nitrate of silver, a blood-red liquid, and afterwards 
 reduced silver. Hence, and from the analysis, Bolley concludes that this substance is 
 quercetin (q, v.) 
 
 CRRirsOTZIiX:. See SERPENTINE. 
 
 CHUZiARZOSE. Uncrystallisable sugar. (See SUGAR.) 
 
 CHITSITE. See OIJVINE. 
 
 CHYLE. (Lehmann, Gmeliris Handbuch, viii. 216 ; Physiological Chemistry, ii. 
 281. Pelouze and Fremy, Traite, vi. 162). Chyle is that portion of the products of 
 digestion which is absorbed by the lacteal vessels terminating in the inner surface of 
 the small intestines, chiefly the jejunum, and thence passing by numerous converging 
 streams into the main trunk of the absorbent system, called the thoracic duct, through 
 which it is gradually poured into the blood of the left subclavian vein, at a short distance 
 before it enters the right side of the heart. 
 
 The physical properties of chyle differ according to the nature of the animal to 
 which it belongs, the condition of the animal, whether lately fed or fasting, and the 
 nature of the food which has been taken. Chyle obtained from the thoracic duct 
 during digestion, is an opalescent, milky, yellowish-white or pale red liquid, having a 
 faint, peculiar odour, a somewhat saline and mawkish taste, and very weak alkaline 
 reaction; its specific gravity varies from 1 -01 2 to 1*022. Nine or ten minutes after 
 removal from the vessels, it coagulates ; the coagulum, which contracts in from two to 
 four hours, is smaller in bulk compared with the serum than that of blood ; it is very soft, 
 easily torn, and sometimes gelatinous. If of a yellow colour, it generally becomes some- 
 what reddish on exposure to the air, an effect especially observed in the chyle of 
 horses. The stTum of chyle, after separation from the coagulum, is never quite clear ; 
 it does not usually become turbid when mixed with water ; on boiling with water, a 
 
CHYLE. 961 
 
 milky turbidity appears in the liquid, which, however, generally deposits only a few 
 small clots. Acetic acid often produces a turbidity in the serum, and the filtered 
 liquid when evaporated exhibits on its surface, colourless, transparent films of albumi- 
 nate of sodium. Ether does not coagulate chyle-serum, but renders it clearer, and 
 between the ether and the serum there is formed a cream-like stratum of a dirty 
 yellowish -white colour. 
 
 The chyle of birds, amphibia, and fishes, is nearly transparent and colourless ; in 
 horses, it is of a deeper red colour than in any other animals which have been 
 examined with reference to this subject. That of carnivora is comparatively thick and 
 milky ; that of herbivora, thinner and more transparent ; in cats, it is of a perfectly 
 milky whiteness, whatever may be the nature of their food. During digestion, the 
 chyle is for the most part very turbid ; at other times it forms a faintly opalescent 
 fluid, exhibiting a reddish colour only in the thoracic duct. 
 
 The morphological elements of the chyle, are: 1. Extremely small granules, consist- 
 ing of drops of fat enclosed in an albuminous envelope. 2. Granules bound together 
 by a hyaline substance, with or without nuclei, and separate granules with distinct 
 nucleus. 3. The so-called chyle-cells, 0-002 to 0'0055 of aline in diameter, the granules 
 of which mostly become visible on addition of water or acetic acid. 4. The transition 
 forms of the several structures from the more simple to the more complex. 5. A small 
 quantity of coloured blood-cells, especially in the chyle of the thoracic duct. 
 
 The chemical constituents of chyle are very nearly the same as those of the intercellular 
 fluid of the blood. It is difficult, however, to obtain chyle of constant composition, 
 partly because it varies with the quality and quantity of the food taken, partly because 
 it is always more or less mixed with lymph and blood. 
 
 The fibrin of chyle is in general less contractile and more gelatinous than that of 
 blood ; like the fibrin of many pathological exudations, and that of fish, it sometimes 
 redissolves after coagulation, especially if heated ; it is usually destitute of the fibrous 
 structure of blood-fibrin ; dissolves very easily in dilute alkalis, carbonic acid, and 
 organic acids; also, after awhile, in solution of nitre, and even in sal-ammoniac; from 
 its solution in acetic acid, it is completely precipitated by sal-ammoniac, and from its 
 solution in sal-ammoniac by acetic acid. 
 
 The albumin of chyle contains a larger amount of alkali than that of blood ; it is 
 not rendered turbid, even by very great dilution with water ; when boiled, it forms, 
 not coherent flocks, but a milk-white opaque liquid ; on evaporation, colourless films 
 form on the surface. The aqueous extract of the chyle-residue has a strong alkaline 
 reaction ; on neutralising it with acetic acid, a turbidity is produced, which afterwards 
 redissolves ; on subsequently adding ferrocyanide of potassium, a copious precipitate is 
 formed. The original aqueous extract becomes strongly turbid by boiling with sal- 
 ammoniac, also on addition of nitric acid. From chyle-albumin exhausted with water, 
 alcohol, and ether, Lehmann obtained 2 '06 8 per cent, of ash, containing a considerable 
 quantity of alkaline salt which effervesced with acids. 
 
 The fat of chyle is mostly unsaponified in the smaller lacteals, saponified in the 
 thoracic duct. Chyle does not appear to contain any crystallisable fat. 
 
 The existence of sugar in chyle is doubtful ; that of bile-constituents, though pro- 
 bable, has not been demonstrated. Lactic acid was found by Lehmann in the chyle of 
 two horses, one of which had been fed two hours before death, with oats, the other with 
 starch. 
 
 Chyle is very rich in alkalis, combined partly with albumin, partly with lactic and 
 sebacic acids; hence the aqueous solution of the ash has a strong alkaline reaction, 
 and effervesces with acids. Sulphates of the alkali-metals are found in the ash, but 
 not in the chyle itself. Sulphocyanides are not found. Alkaline phosphates occur in 
 small quantity only, even after the digestion of vegetable food. The chlorides of sodium 
 and potassium occur in large quantity. 
 
 Iron is found in the serum of chyle, but its presence may be due to admixed blood- 
 ceDs. 
 
 During fasting or scanty nutrition, the chyle is poorer in solid constituents, espe- 
 cially fat, and consequently has a turbid but not a milky appearance. 
 
 Food rich in fat, whether animal or vegetable, increases the quantity of fat in the 
 chyle. 
 
 In the contents of the thoracic duct, two hours after death, of a man killed by 
 drowning, Rees found 98'48 per cent, water, 7'08 albumin, with traces of fibrin, 0'56 
 aqueous extract, 0-5 alcoholic extract, 0'44 chloride, carbonate, and sulphate of potas- 
 sium, with traces of phosphate of potassium and oxide of iron, and 0'92 fatty matters. 
 
 F. Simon has given the following analyses of the chyle of three horses, the first fed 
 on peas, the other two on oats : 
 
 VOL. I. 3 Q 
 
962 CHYME CICHORIUM INTYBUS. 
 
 T. II. III. 
 
 Water 949-670 028-000 916-000 
 
 Fat 1-186 10-010 0-900 
 
 Albumin 42717 46-430 60-530 
 
 Fibrin 0-440 0-805 0-900 
 
 Hematosin 0-474 trace 5-691 
 
 Extractive matter and ptyalin . . . 8*360 5-320 5-265 
 Chloride and lactate of sodium with traces of 
 
 calcium-salts . . . . . . 7-300 6700 
 
 Sulphate and phosphate of calcium with traces 
 
 of oxide of iron 1-100 0-850 
 
 1002-847 998-965 996-836 
 
 The first of these analyses does not, however, admit of direct comparison with the 
 others, as it evidently applies to the organic matter alone. 
 
 In the chyle of a cat, Nasse found in 1000 pts. : 9057 water, and 94-3 solid matter, 
 consisting of 1'3 fibrin, 327 fatty matter, 48'9 albumin, globules resembling those of 
 the blood, and extractive matter, 7*1 chloride of sodium, 2-3 other soluble salts, trace 
 of iron, and 2*0 earthy salts. 
 
 CH YIWE. This name, now but little used, was applied to the products of digestion 
 contained in the small intestines, before they have been submitted to the action of the 
 bile and pancreatic juice. 
 
 CHYMOSXN 1 . A peculiar nitrogenous matter existing in the gastric juice (q. v.} ; 
 also called pepsin or gasterase. 
 
 CHTTTOPHYXiXiITE. A name applied by Hausmann to certain slags from blast- 
 furnaces, having a broadly laminar structure. They are mainly ferrous silicates, 
 2Fe 2 0.3Si0 2 , the iron being partly replaced by calcium and the silica by alumina. 
 (Jahresber. d. Chem. 1850, pp. 26, 710; 1851, p. 768; 1856, p. 842.) 
 
 CHYTOSTXZiBITE. Radiate blast-furnace slags, having the composition of 
 augite, IVFSiO 3 or M 2 O.Si0 2 , the silica being partly replaced by alumina. (Haus- 
 mann, Jahresb. d. Chem. 1856, p. 843.) 
 
 CXBOTXTTOX CUMXKTGXX. An East Indian fern, the hairy stem of which is 
 much used as a means of arresting haemorrhage. It contains wax, resin, tannic acid, 
 crenic acid, &c. (v. Be mm el en, Viertelj. pr. Pharm. v. 321.) 
 
 C 1C ETC. ARIETITJU1VI. The Chickpea. The hairs of the stem, leaves, and 
 other parts of this plant exude an acid liquid, containing oxalic, acetic, and perhaps 
 malic acid, and, according to Dispan, another acid peculiar to the plant. 
 
 CXCHORIUTO ENDIVIA. See ENDIVE. 
 
 CXCHORXUIK INTYBUS. Chicory. The root of this plant is extensively 
 used for mixing with coffee. The following table exhibits the composition of the 
 organic part of the wild and cultivated varieties, as determined by v. Bibra : 
 
 Cultivated. Wild. 
 
 Fat, insoluble in alcohol 0-07 0-47 
 
 Kesin 0-84 0-96 
 
 Organic acid, precipitable only by subacetate of lead . 1-01 1-18 
 
 Organic acid, precipitable also by the neutral acetate . 2 -54 2*51 
 
 Sugar 22-08 37-81 
 
 Inulin 19-12 10-90 
 
 Albumin , . 0'12 0-15 
 
 Tannic acid and volatile oil trace trace 
 
 Woody fibre . 54-21 46-00 
 
 99-98 
 
 The chief difference in the composition of the two varieties appears to be in the re- 
 lative proportions of inulin and sugar. 
 
 Ander son.(Highland Agric. Soc. Journ. 1853, p. 61) found in a specimen of chicory 
 cultivated in Yorkshire, 1-6 per cent, nitrogen and 3-6 ash ; in another, from the neigh- 
 bourhood of Glasgow, 1-5 per cent, nitrogen and 67 ash. 
 
 The leaves contain in 100 pts. 90-9 water and 1-42 ash. (Anderson.) 
 
 The composition of the ash of the root and leaves of chicory, as determined by 
 Anderson (loc. cit.\ and by Graham, Stenhouse, and Campbell (Chem. Soc. 
 Qu. J. ix. 45), is as follows : 
 
CICUTINE CIDER. 
 
 963 
 
 Composition oj- CHICORY- ASH in 100 pts. 
 
 
 Root. 
 
 Leaves. 
 
 
 Anderson. 
 
 ^x 
 Graham, Stenhouse, and Campbell. 
 
 Anderson. 
 
 
 
 
 Darkest 
 
 
 | 
 
 
 
 Scotch. 
 
 Yorkshire. 
 
 English 
 
 English. 
 
 Foreign. Guernsey. 
 
 
 
 
 
 (Yorkshire.) 
 
 
 
 
 
 Potash 
 
 34-6 
 
 55'2 
 
 37-07 
 
 27-13 
 
 40'20 
 
 41-41 
 
 4G-6 
 
 Soda 
 
 8-9 
 
 . 
 
 8-99 
 
 1646 
 
 2-77 
 
 4-92 
 
 
 Lime 
 
 10-1 
 
 7-9 
 
 1038 
 
 10-53 
 
 6-79 
 
 6'85 
 
 11-3 
 
 Magnesia . 
 Ferric oxide 
 
 6-7 
 0-8 
 
 4-1 
 I'O 
 
 5-83 
 4-22 
 
 7-87 
 3-41 
 
 4-66 
 7-24 
 
 4-97 
 455 
 
 2'6 
 1 
 
 Silica 
 
 4-4 
 
 1-3 
 
 3-81 
 
 2-61 
 
 12-75 
 
 10-52 
 
 08 
 
 Sulphuric acid (an- 
 hydride) 
 
 15-2 
 
 6-2 
 
 10'95 
 
 11-48 
 
 7'32 
 
 776 
 
 7-1 
 
 Phosphoric acid (an 
 hydride) 
 
 16-2 
 
 13-0 
 
 ll'Sl 
 
 12-29 
 
 9-60 
 
 8-59 
 
 7-1 
 
 Chloride of potassium 
 
 
 
 23 
 
 
 
 
 
 
 
 
 
 1-6 
 
 sodium 
 
 30 
 
 8'8 
 
 
 
 
 
 
 
 _ 
 
 1 1 
 
 Chlorine . 
 
 
 
 _ 
 
 5-46 
 
 5-10 
 
 4-39 
 
 5-89 
 
 
 Carbonic acid (anhy 
 dride) . 
 
 
 
 __ 
 
 1-97 
 
 3'14 
 
 3-81 
 
 4-12 
 
 20-5 
 
 
 99-9 
 
 99-8 
 
 100-49 
 
 100-02 
 
 99-53 
 
 99-53 
 
 99-7 
 
 When chicory-root is roasted, several volatile products are given off, and on con- 
 densing them, a yellowish liquid .is obtained, which has a sharp unpleasant odour, 
 colours the skin permanently dark brown, and contains tannic acid. The aqueous 
 infusion of the roasted chicory contains sugar, a bitter substance, empyreumatic oil, 
 substances which exert a strong reducing action on gold and silver-salts, and organic 
 acids precipitable by lead-salts. It has a disagreeable taste, and, if taken in con- 
 siderable quantity, produces nausea and sometimes giddiness. (Handw. d. Chem. 
 ii. [2] 24.) 
 
 CICUTIWE. An alkaloid but little known, said to exist in the water-hemlock, 
 Cicuta virosa. (P o lex, Arch. Pharm. xviii. 174. Wittstein, Buchner's Eepert. 
 xviii. 19.) 
 
 CIDER. A fermented liquor prepared from apples. Large quantities of it are 
 made in Herefordshire, Devonshire, and the adjoining counties ; in the counties of 
 Waterford and Cork in Ireland ; in Normandy and Picardy in France; in Belgium; in 
 Germany ; and in many parts of the United States. 
 
 The apples used in the preparation of cider, ripen at different seasons ; in this 
 country, the earliest begin to fall from the trees at the end of September, but the ma- 
 jority do not attain their maturity till about the end of November or the beginning of 
 December. 
 
 To make good cider, it is necessary that the apples be quite ripe, to ensure which, it 
 is customary to leave them to ripen for a month or more after gathering ; they must 
 not, however, be allowed to get over-ripe, otherwise the quantity of sugar will diminish. 
 The average proportion of sugar in apples at different stages of maturity, has been 
 found to be as follows : 
 
 Unripe. 
 4-90 
 
 Ripe. 
 11-00 
 
 Over-ripe. 
 7-95 
 
 To make cider, the apples are thrown into a circular stone trough, usually about 
 18ft. in diameter, called the chase, round which the runner, a heavy circular stone, is 
 turned by one or sometimes by two horses; the pulpy fruit or " mist" is then enclosed 
 in coarse hair-cloths, and subjected to pressure by a screw-press, and the brown juice 
 which exudes is poured into casks placed either out of doors, or in sheds where there is 
 a free current of air. Sometimes the dry residue which remains in the bags, is mixed 
 with water, ground again, and the liquor pressed out as before. This latter product 
 makes what is called " water-cider," a thin unpalatable liquor which is given to the 
 labourers early in the year. 
 
 About three or four days^after the juice has been transferred to the casks, it begins 
 to ferment, the thick heavier parts then subsiding to the bottom, while the lighter 
 become clear bright cider. This is then racked off into another cask, and the sediment 
 is put to strain through linen bags, the liquid which oozes through being restored. 
 
 The fermentation is the most delicate part of the process ; slight fermentation leaves 
 the liquor thick and unpalatable ; rapid fermentation impairs its strengh and durabilty ; 
 and excessive fermentation makes it sour, harsh, and thin. Other things being eqxial, 
 that cider will probably prove the best in which the vinous fermentation has proceeded 
 
<J64 CIMICIC ACID CIMOLITE. 
 
 slowly, and has not been allowed to pass into the acetous. If the cider does not clear 
 spontaneously, finings, such as isinglass, eggs, or blood, are added, as in the preparation 
 of beer. 
 
 At the beginning of January, the cider is moved into cellars, where, by large 
 growers, it is frequently stored in casks of great capacity, containing 1000, 1500, or 
 even 2000 gallons. In March, the liquor is bunged down ; it is then fit for sale, and 
 may be used soon afterwards, though it will greatly improve by keeping. For bottled 
 or effervescing cider, the liquor should be bottled or wired down in the September or 
 October after it is made ; some persons prefer an earlier time, the end of April or the 
 beginning of May. A more effervescent liquid is thus obtained, but considerable loss 
 occurs from the bursting of bottles. (Penny Cyclopaedia.) 
 
 The strongest cider contains in 100 volumes, 9'87 volumes of alcohol of 92 per cent. ; 
 the weakest, 5 '21 volumes. (Brande.) 
 
 CIMICIC ACID. C 15 H 28 2 = go. (Carius, Ann. Ch. Pharm. cxiv. 
 
 147.) An acid, belonging to the oleic series, contained in the fetid oily liquid ejected 
 by a kind of bug (Ehaphigaster punctipennis) when irritated. To prepare it, the in- 
 sects are treated with strong alcohol, which extracts a brown resinous substance, then 
 macerated with cold ether. The solution thus obtained, yields the acid by evaporation, 
 as a coloured mass ; it is purified by. converting it into a barium-salt, washing with 
 water and with dilute alcohol, then decomposing the salt with hydrochloric acid, and 
 drying the resulting fat between 40 and 50 C. Two or three hundred of the insects 
 yield about 12 grins, of the fatty acid : the insects freed from fat and dried, weighed 
 23 grms. 
 
 Cimicic acid is a yellow crystalline mass, having a peculiar rancid odour : lighter 
 than water and insoluble therein ; very little soluble in alcohol, easily in ether, from 
 which it crystallises by slow evaporation in stellate groups of colourless needles. It 
 melts at 44 C., and, when subjected to dry distillation, yields, besides gases, an oil 
 which solidifies on cooling, and appears to contain some undecomposed acid. 
 
 Cimicic acid, treated with pentackloride of phosphorus, gives off hydrochloric acid 
 gas, and forms a liquid which, when shaken up with cold water, yields chloride of 
 cimicyl, C 15 H 27 O.C1, as a heavy oil, which solidifies at about 44 C., does not crys- 
 tallise distinctly ; dissolves in ether without alteration ; is immediately decomposed 
 by alcohol into cimicic ether and hydrochloric acid ; and by potash into cimicate and 
 chloride of potassium. 
 
 Cimicic acid in alcoholic solution is strongly acid. It dissolves easily, with aid of 
 heat, in aqueous alkalis. 
 
 The cimicates have the composition C 15 H 27 M0 2 . Those of the alkali-metals 
 dissolve in a small quantity of water, but a larger quantity renders the solutions 
 opalescent ; they froth with soap-solution, and are precipitated from their aqueous 
 solutions by excess of alkali and by chloride of sodium. The cimicates of the earth- 
 metals and heavy metals are nearly or quite insoluble in water and alcohol ; the lead- 
 salt only appears to be slightly soluble in ether. The silver-salt blackens quickly 
 when exposed to light. 
 
 Cimicate of Ethyl, C 15 H 2 (C 27 H 5 )0 2 , obtained by treating chloride of cimicyl with 
 with alcohol and precipitating by water, is a light yellow oil, smelling like the free 
 acid, but stronger : it is lighter than water ; does not solidify at C ; dissolves readily 
 in alcohol ; turns brown when heated. 
 
 CIIKIVXOXi. Syn. with HYDBIDE OF CINNAMYL (p. 988). 
 
 CIMIVEYI.. Lowig's name for the radicle C 9 H 7 , which he supposes to exist in 
 cinnamic acid. 
 
 CXMOXiXTE or CXMOXiXAlT EARTH, the cimolia of Pliny, which was used 
 by the ancients both medicinally and for cleaning cloths, and which has been con- 
 founded with fuller's earth and tobacco-pipe clay, is found in the island of Argentiera, 
 the ancient Cimolus, also in Bohemia and in Eussia. It is of a light greyish-white 
 colour, acquiring superficially a reddish tint by exposure to the air ; massive ; of 
 an earthy, uneven, more or less slaty fracture ; opaque when shaved with a knife, 
 smooth, and of a greasy lustre ; tenacious, so as not without difficulty to be powdered or 
 broken ; and adhering pretty firmly to the tongue. Its specific gravity is 2'18 2*30. 
 It is immediately penetrated by water, and splits into thin laminae of a curved slaty 
 form. Triturated with water, it forms a pappy mass; and 100 grains will give to three 
 ounces of water the appearance and consistence of a thickish cream. If left to dry- 
 after being thus ground, it detaches itself in hard bands, somewhat flexible, and still 
 more difficult to pulverise than before. 
 
 When it is ground with water, and applied to silk or woollen fabrics greased with oil of 
 almonds, the oil is completely discharged by a slight washing in water, after the stuffs 
 
CINACROL CINCHONA BARK. 965 
 
 have been hung up a day to dry, without the least injury to the beauty of the colour. 
 It is still used by the natives of Argentiera for the same purposes as of old. 
 
 The following are analyses of cimolite: a. From Argentiera, by Klaproth: 
 b. From Alexandrowski in Eussia, by Ilimoff: c. A pseudomorph of augite (also 
 called anauxite), from the decomposed basalt of Bilin, Bohemia, by Kammelsberg : 
 d. Also called pelikanite, from the decomposed granite of Kiew in Eussia, by Oucha- 
 koff. (Bammdsberg' s Mineralchemie, p. 583.) 
 
 SiO 2 A1 4 3 Fe 4 3 Ca 2 O Mg 2 K'O P 2 5 IPO 
 
 a. 63-00 23-00 1-25 12-00 = 99-25 
 
 b. 63-52 23-55 12'00 = 99-07 
 
 c. 62-30 24-23 0'83 12-34 = 9970 
 
 d. 65-66 22-84 0-44 0'56 0'30 0'17 9'31 = 99-28 
 
 The first three analyses agree nearly with the formula 2Al 4 3 .9Si0 2 + 6aq., which is 
 that of a sesquisilicate, and reducible to 2aTO.3Si0 2 + 2aq. or a/ 4 Si0 4 .Si0 2 -i- 2aq. ; the 
 fourth contains the same proportions of silica and alumina, but only 4 at. water, 
 2Al 4 3 .9SiO- + 4aq. 
 
 Cimolite appears to be formed from augite containing alumina and magnesia, by the 
 action of infiltrating waters containing carbonic acid, which carry away the magnesia, 
 leaving a hydrous silicate of aluminium ; an addition of alumina may probably take 
 place through the accompanying decomposition of associated felspar. (Dana, ii. 164.) 
 
 CXNACROXi. A product of the action of iodine on wormseed oil (q. v.) 
 
 CINJEBENE and CIN-ZBENE-CAIVIPHOR. Constituents of wormseed-oil, 
 
 according to Hirzel. 
 
 CINJEPHAWE, CIWJEPHETO'E, CXCTJEPHONE. Products obtained, accord- 
 ing to Hirzel, by the action of iodine on wormseed-oil (q. v.) 
 
 CINCHONA BARK. Cortex Chinee, C. Peruvianus, Quinquina, Cascarilla. 
 This name is applied to the bark of the stem and branches of various species of Cin- 
 chona and other genera of the order Bubiacece, sub-order Cinchonece. Those which are 
 obtained from trees of the genus Cinchona, are called true cinchona barks; they 
 contain quinine and cinchonine, and have long been known for their antifebrile pro- 
 perties; the barks of the other genera of the sub-order above-mentioned, chiefly 
 Ladcnbergia and Exostemma, are called false cinchona barks; they contain certain 
 proximate principles, likewise found in the true cinchona barks, namely quinic acid, 
 quinovic acid, quinotannic acid, and cinchona-red, but no alkaloids. 
 
 The antifebrile barks were first introduced into Europe from Peru, about the year 
 1638, by the Countess of Chinchon, wife of the Viceroy of Peru (in whose honour the 
 name Cinchona was given to the genus by Linnseus), and a few years later by thu 
 Jesuits, and soon acquired great celebrity for the cure of intermittent fevers, being 
 known by the names Pulms Comitissce, Jesuiticus, Cardinalis, Patrum. The trees 
 which yield them were first recognised and described, about a century later, by the 
 French astronomer La Condamine, in his journey in Peru. 
 
 The true cinchonas grow on the wooded slopes of the Cordilleras, from western 
 Venezuela to northern Bolivia, between 10N. and 19 S. latitude, in a narrow zone 
 extending through a vertical height of about 6400 feet. The barks which are richest 
 in alkaloids, and are exported (CascarilZo'sjino's), occur most abundantly from 7N. 
 to 15 S. latitude, and as they require a cool moist climate, they occupy the region 
 from 11,150 to 6400 feet above the sea-level, whilst those which contain smaller 
 quantities of the alkaloids, and are therefore not fit for exportation, occupy a warmer 
 and drier zone, between 6400 and 4800 feet in vertical height. With these also are 
 found the Ladcnbergias, which produce false cinchona barks ; they extend also 2000 
 feet lower through the tropical part of the continent. The Exostcmmas, which also 
 produce false cinchona barks, inhabit only the hot zone, and are found not only on 
 the continent, but on the islands. Since 1853, the most highly prized cinchonas have 
 been successfully cultivated in Java. The cultivation has also been attempted in 
 Algeria and in India. 
 
 The collection of the bark takes place in New Granada at all times of the year ; 
 in Peru and Bolivia, only in the dry season. The inner bark of the stems and larger 
 branches, after having been freed from the outer bark, is very carefully dried over a 
 fire for three or four weeks, the weight of the dried products being about one-third of 
 that of the fresh bark. According to Karsten, a tree 60 feet high and 5 feet in 
 diameter, yields about 10 cwt. of dry bark ; but such specimens are not often met with. 
 In Ecuador and northern Peru, the bark is taken chiefly from the branches; in 
 southern Peru and Bolivia, from both stems and branches ; it is dried in the sun 
 
 3 Q 3 
 
.966 CINCHONA BARK. 
 
 either in the forest itself, or in drier situations lower down the hill-side. According 
 to Pasteur, the process of drying in the sun is injurious. 
 
 The TRUE CINCHONA BARKS known in commerce, are of three kinds, grey or brown, 
 yellow, and red. They come to market either in rolled quills, or in flat or hollowed 
 oblong pieces of very various dimensions. They have a more or less splintery -fibrous 
 texture, contain the cinchona alkaloids, quinine, cinchonine, quinidine, &c., and when 
 coarsely powdered and heated in a test-tube, give off a red tar. 
 
 a. Grrey Cinchona-barks. China fusca s. grisea. These barks are obtained 
 from the branches, and have therefore the form of quills ; they are whitish on the 
 outside, with spots of grey, greyish-brown or brown, sometimes black, fine-fissured, of 
 even fracture, splintery only on the inner surface, and contain more cinchonine than 
 quinine. Five species are enumerated, namely, Huanoco, Loxa, Pseudoloxa, Huama- 
 lics, and pale Jacn bark. 
 
 b. Yellow or Orange-yellow barks. Cinchonaflava s. aurantiaca. These barks 
 are obtained from the stems and larger branches, and consist wholly or nearly so of 
 the bass or inner bark ; hence they have a fibrous or splintery texture. The alkaloids 
 contained in them are chiefly quinine and quinidine. The most important species is 
 the Royal, King's or Calisaya bark, of which there are three varieties, viz. 
 1. Fine Calisaya bark, from C. Calisaya, which occurs either in quills or rolls, of 
 1 tol| inches diameter, partly covered with the outer bark, and is then called Cinchona 
 Calisaya tecta s. convoluta; or in flat plates destitute of outer bark ; C. Calisaya nuda 
 s.plana; this last variety is the richest of all the barks in alkaloids. 2. C. Calisaya 
 morada, from C. Boliviana; and 3. C. Calisaya fibrosa s. scrobiculata. There 
 are four other species of yellow bark, viz. Cusco bark (Weddell) ; Carthagena or 
 Bogota bark, also called Cinchona flava fibrosa; Cinchonaflava dura; and 
 Cinchona Pitaya. 
 
 c. Red Barks. Cinchona rubra. These barks are obtained from the stems 
 and larger branches ; they are mostly of brown-red colour, with proportionately thick 
 outer bark, and strong fibrous or splintery bass. They contain more quinine than 
 cinchonine. The species are Cinchona rubra suberosa, from C.succirubra and (7. 
 rubra dura. 
 
 FALSE CINCHONA BARKS are derived chiefly from trees of the genera Ladenbergia 
 and Exostemma. They occur in rolls, half rolls, or flat pieces, having a pre-eminently 
 corky texture. They contain no cinchona alkaloids, and when coarsely pulverised and 
 heated in a test-tube, yield nothing but a dirty yellow or brown tar. The species are : 
 1. Cinchona de Para, obtained from a Ladenbergia. 2. Cinchona nova G-rana- 
 t en sis, from Ladenbergia oblongifolia or magnifo'lia. Pelletier and Caventou found in 
 it quinovic acid and an alkaloid ; Winckler found quinovic acid and cinchona-bitter ; 
 Hlasiwetz found quinic acid, quinovic acid, quino-tannic acid, and cinchona-red. 
 3. Cinchona nova Brasiliensis, from Ladenbergia Riedelana, said to contain quinic 
 and qninovic acids. 4. Cinchona alba Granatensis, from L. macrocarpa, said 
 to contain alkaloids, but the statement is doubtful. 5. Cinchona bicolorata s. 
 Atacamez, s. Pitoya, said to contain an alkaloid pitoyine. 6. Cinchona 
 Caribcea, from Exostemma Caribceum, contains quinovic acid. 7. Cinchona Sta. 
 Lucia, B. Pit on, s. Martinicensis, from Exostemma floribund um. 
 
 The organic constituents of cinchona barks, are quinine, cinchonine, and two or 
 three isomeric modifications of those bases ; aricine ; quinic, quinovic and quinotannic 
 acids; cinchona-red; a yellow colouring matter; a green fatty matter; a small quantity 
 of volatile oil, having the odour of the bark; together with starch, gum, and woody fibre. 
 
 The ash of cinchona barks consists chiefly of carbonate of lime, and varies in 
 quantity from O58 per cent, (in Calisaya bark), to 3 -4 (in ash-bark or pale Jaen 
 bark). The acids of the bark are neutralised, partly by the lime, partly by the alka- 
 loids, and accordingly analysis appears to show that the lime diminishes in proportion 
 as the bark is richer in alkaloids. Some barks, e.g. Calisaya and Huanoco, yield ashes 
 of a green colour, arising from manganate of potassium (Puttfarcken, Pharm. 
 J. Trans, xi. 129). Reichel found in the ash of various cinchona barks, potash, lime, 
 magnesia, silica, and sulphuric acid, with smaller quantities of alumina, iron, manga- 
 nese, phosphoric acid, and chlorine. 
 
 The first chemical examination of cinchona bark appears to have been made in 1785 
 by Hermbstadt, who obtained from it the calcium-salt of quinicacid, which he 
 designated as essential salt of quinine. Schneider in 1807 and Vanquelin in 1808, 
 separated quinic acid from the calcium-salt. Quinotannic acid was discovered by 
 Deyeux in 1793, and obtained in more definite form by Seguin, in 1797. Cinchona- 
 bitter and cinchona-red were obtained from red cinchona bark by Reuss in 1810. 
 At this time, ten years before the discovery of the cinchona alkaloids, Berzelius made 
 a quantitative examination of a yellowish-brown cinchona bark, and found in it 0'5 
 
CINCHONA BARK. 967 
 
 per cent, of green soft resin, winch quickly hardened, 7 '35 quinotannic acid, 6-87 bitter 
 syrupy extract (this contained the alkaloids), 2-5 quinate of potassium and quinate 
 of calcium, coloured by a small quantity of extractive deposit, 1'25 extractive 
 deposit dissolved out by carbonate of potassium, 270 amylaceous gum and 7375 woody 
 fibre. 
 
 Cinchonine appears to have been obtained in an impure state by Gomez of Lisbon 
 in 1811; but its true nature remained unknown till 1820, when Houton-Labillardiere 
 first drew attention to the alkaline reaction of the substance obtained by Gomez, and 
 communicated his observations to Pelletier and Caventou, who, in the same year, suc- 
 ceeded in isolating, first cinchonine, and afterwards quinine, and in proving them 
 to be true vegetable alkaloids. Several isomeric modifications of these alkaloids were 
 afterwards discovered and variously named; but according to Pasteur (Compt. rend. 
 xxxvi. 26; xxxvii. 110), whose results appear to be the most exact, their number may 
 be reduced to four, namely, cinchonicine and cinchonidine isomeric with cincho- 
 nine ; quinicine and quinidine isomeric with quinine. Cinchonicine and quinicin e 
 are produced by the action of heat on cinchonine and quinine respectively ; cinchonidine 
 is found in certain cinchona barks, namely, Huamalies, Maracaibo, and Bogota barks, 
 and quinidine is obtained from the mother-liquors of the manufacture of sulphate of 
 quinine. 
 
 The three isomeric bases of each group are distinguished by their optical rotatory 
 power. (See the several Alkaloids.) 
 
 Aricine was discovered in 1829 by Pelletier and Corriol (J. Pharm. xv. 575), 
 in a white cinchona bark, from Arica. Elaborate examinations of various cinchona 
 barks, were published by Reichardt in 1855, and by Reichel in 1856 ; and lastly, in 
 1860, De Vry published his researches (Bonplandia, viii. 270), on the Cinchona Caly- 
 saya cultivated in Java. 
 
 Cinchona barks are employed medicinally in the form of tinctures and infusions, and 
 were used in this manner, for their febrifuge and tonic properties, long before the dis- 
 covery of the alkaloids ; but as these qualities are likewise possessed by the pure 
 alkaloids, and the administration of these alkaloids is, in many cases, much more con- 
 venient than that of the bark in substance, the alkaloids, especially quinine in the 
 form of sulphate, are prepared from the barks on a very large scale ; the value of a 
 bark to the manufacturer may indeed be said to depend on the quantity of sulphate of 
 quinine that it will yield. It is found, however, that the medicinal properties of the 
 barks are due to the quinic and other acids which they contain, as well as to the 
 alkaloids, and consequently that the bark in substance cannot in all cases be advan- 
 tageously replaced by the pure alkaloid. At one time indeed it was supposed that the 
 medicinal efficacy of the barks depended chiefly on the tannin contained in them. 
 Berzelius wrote in 1831 {Traite de Chimie, Paris, v. 587) : " There is a law in Sweden 
 in virtue of which, every cinchona bark imported into the country must be tested witl 
 infusion of galls, ferric sulphate, solution of gelatin, and tartar emetic ; and it is proved, 
 by an experience of sixteen years, that the most efficacious bark is that which gives 
 the strongest precipitate with solution of gelatin and tartar- emetic, in other words, 
 which contains most tannin." The barks which appear to be best adapted for medici- 
 nal use are, the flat Calisaya and the Huanoco barks, the former containing the largest 
 proportion of quinine and quinotannic acid, while the latter is richest in cinchonine 
 and quinic acid. 
 
 Reactions of Cinchona BarJcs. The aqueous infusion of these barks contains the 
 alkaloids in combination with quinic and the other acids, and as these salts, and 
 likewise the starch, are more soluble in hot than in cold water, the liquid always 
 becomes turbid on cooling. To extract the whole of the bases, it is necessary to 
 
 acidulate with hydrochloric or sulphuric acid. 
 The solution thus obtained mav be tt 
 
 may be tested : 
 
 1. For alkaloids, which, if present, will give a white precipitate with tannic acid, 
 and a yellow crystalline precipitate with dichloride of platinum. Another mode of 
 testing for the alkaloids, is to precipitate the acid solution with carbonate of sodium, 
 and distil the precipitate with excess of caustic alkali, whereby a distillate of chinoline 
 (p. 869) will be obtained. 
 
 2. For Qui no-tan nic acid.- White precipitate with .solution of gelatin ; green 
 with ferric salts ; dirty white with tartar-emetic. 
 
 3. For Qui no vie acid. If this acid is present, sulphate of copper first colours the 
 liquid green and then throws down a precipitate, which when collected and washed, 
 has a bitter metallic taste. Winckler proposes to estimate the relative value of cin- 
 chona barks by the amount of quinovic acid thus precipitated, inasmuch as the bitter- 
 ness of a bark depends partly (and in the case of the false barks, exclusively) on the 
 presence of quinovic acid. 
 
 4. For Quinic acid. This acid distilled with sulphuric acid and peroxide of man- 
 
 3d 4 
 
968 CINCHONA BARK. 
 
 ganese, yields a distillate of quinone, which is a yellow crystallisable substance, having 
 a pungent odour, and soluble in water. The aqueous solution mixed with ammonia, 
 absorbs oxygen from the air, and assumes, first a brown, then a black colour ; a re- 
 action which will indicate the presence of very small quantities of quinic acid. Chlo- 
 rine-water changes the colour of the aqueous solution of quinone from yellow to bright 
 green. The formation of quinone in this manner is proposed by Stenhouse (Mem, 
 Chem. Soc. ii. 226), as a means of distinguishing between true and false cinchona 
 barks, the former alone containing quinic acid. According to other authorities, how- 
 ever (p. 964), this acid is likewise present in some of the false cinchonas. 
 
 For the quantitative estimation of the alkaloids, the following methods may be used. 
 
 1. One drachm of the finely powdered bark is to be boiled for a few minutes with 
 an ounce of water and half a drachm of strong acetic acid ; the liquid filtered off, the 
 residue boiled with a little dilute acetic acid ; the liquid again filtered off, and the 
 powder washed ; the whole of the liquid evaporated to dryness on a water-bath ; and 
 the extract dissolved in a little water and again evaporated, to expel all the free acetic 
 acid. The residue is then to be treated with absolute alcohol and blood-charcoal ; 
 the colourless solution filtered off, and the residue exhausted with alcohol. To this so- 
 lution a few drops of hydrochloric acid are to be added, and next a solution of chloride 
 of platinum as long as it causes turbidity ; and the precipitate of chloroplatinnte of 
 quinine and cinchonine transferred to a weighed filter, washed with alcohol, dried and 
 weighed. The platinum-salt of quinine contains 44*3 per cent, of that base ; the cin- 
 chonine-salt 43 per cent, of cinchonine : hence the proportion of the two alkaloids may 
 be found by the method of indirect analysis (p. 224) (Duf los). The alkaloids might 
 also be precipitated by tannic acid and infusion of gall-nuts. 
 
 2. Fifty grains of the pill verised bark is treated with a little diluted hydrochloric acid ; 
 the liquid filtered, and the residue washed with a mixture of alcohol and a few drops 
 of the same acid. The dark brown solution is then mixed with a little powder of hy- 
 drate of lime, so as nearly to decolorise it, and the precipitate, being thrown on a filter, 
 is washed with alcohol. The liquid contains the organic bases in the free state. It is 
 to be neutralised with hydrochloric acid, diluted with water, and freed from alcohol 
 by evaporation. When it is reduced to two or three drachms measure, the bases are 
 to be thrown down with solution of caustic ammonia; and the precipitate is to be filtered, 
 washed with cold water, dried, and weighed. By digesting it with ether, the quinine 
 is dissolved, and the cinchonine remains behind. 
 
 As the alcoholic solution of the bases thrown down by the alkali is often rather 
 strongly coloured, and requires to be decolorised by animal charcoal, alum, protochloride 
 of tin, or hydrate of lead, which occasions loss, Thibouwery extracts the alkaloids 
 from the precipitate by oil of turpentine, or other non-oxygenated oil, and Eabourdin 
 effects the solution by means of chloroform. The same object is attained, according to 
 Badollier and Scharlan, by subjecting the bark, before treating it with acidulated 
 water, to the action of dilute potash, which removes the tannic acid and the cinchona- 
 red. 
 
 3. A quarter of a pound of the coarsely powdered bark is boiled for half an hour 
 with very dilute hydrochloric acid ; this operation is repeated on the filtered residue ; the 
 final residue is washed with water ; the whole of the liquors evaporated to dryness over 
 the water-bath ; and the extract redissolved in faintly acidulated water, on the bath. 
 Much of the cinchona-red will remain undissolved. The filtrate is to be concentrated 
 to a small bulk, its bases precipitated by ammonia, and the mixture drained and washed 
 with cold water on a weighed filter. The quinine and cinchonine may then be sepa- 
 rated and determined, as above, by means of ether. 
 
 4. An ounce of the pulverised bark is digested with five ounces of water containing 
 hydrochloric acid (1| drachm of acid to a pint of water); the extract is pressed through 
 linen, the operation being repeated three times with each four ounces of the acidulated 
 water ; the extracts are then evaporated on the water-bath to six ounces, and the residue 
 washed. From this solution, the alkaloids are precipitated by soda-ley, till an alkaline 
 reaction is produced; the liquid is then supersaturated with acetic acid; and after the 
 cinchona-red has separated, the nearly limpid liquid is to be filtered. The filtrate 
 is again precipitated with soda-ley ; the precipitate left to settle for a day ; the clear 
 liquid decanted ; the precipitate collected on a small filter, and left to drain well ; the 
 still moist filter, with the precipitate, repeatedly shaken up with chloroform; the clear 
 chloroform containing the alkaloids poured into a tared capsule; the operation re- 
 peated three times, with fresh chloroform ; and the liquid left to evaporate in the cap- 
 sule : the net weight gives the total amount of the alkaloids. The quinine may then 
 be completely dissolved out by ether, the residue in the capsule consisting wholly of 
 cinchonine, which may be weighed. In this manner the relative quantities of the two 
 bases are determined. 
 
 A crystalline deposit in the amber-like mass of quinine, indicates the presence of 
 
CINCHONA BAKU CINCHONA-RED. 
 
 969 
 
 isomeric alkaloids. To separate cinchonidine (Pasteur's, p. 965), dissolve 1 gramme 
 of the mass in 15 drops of dilute sulphuric acid and 24 drops of water, then add 20 
 drops of ether and 30 drops of ammonia : the quinine will then dissolve, leaving the 
 cinchonidine, provided the quantity of the latter is not less than 10 per cent. Smaller 
 quantities may be separated by means of ether already saturated with cinchonidine, 
 which will still dissolve quinine. (Zimmer.) 
 
 Quinidine may be separated from quinine by the greater solubility of its oxalate in 
 cold water ; on treating a solution of quinine with oxalate of ammonium, the quinine 
 is almost wholly precipitated as oxalate, whilst the quinidine-salt remains dissolved. 
 
 The following table (p. 968) exhibits the proportions of the alkaloids contained in dif- 
 ferent cinchona-barks. The determinat ions must not however be regarded as very exact, 
 partly because the barks known in commerce by the several names in the table are 
 usually mixtures of different sorts, partly also because different methods of analysis 
 often give different results. According to Wittstock, the precipitation of the bases 
 from the acid extract of the bark by alkalis, is not complete, inasmuch as a somewhat 
 considerable precipitate may afterwards be obtained with tannic acid. Moreover, the 
 precipitates which contain the colouring matter always retain a certain portion of the 
 alkaloids, and charcoal, if used to decolorise the extract, carries down nearly the whole 
 of the bases ; lastly, the separation of quinine from cinchonine by ether is by no means 
 complete. 
 
 Keichardt has determined the whole of the constituents of various cinchona-barks. 
 The following is an extract from his table : 
 
 Composition of CINCHONA-BARKS. 
 
 
 Cinchona 
 flava 
 fibrosa. 
 
 Cinchona 
 rubra. 
 
 Cinchona 
 Huanoco. 
 
 Cinchona 
 Calisaya 
 plan a. 
 
 Cinchona 
 Calisaya 
 convoluta. 
 
 Quinine . 
 Cinchonine . 
 Ammonia 
 
 0-705 
 0-245 
 0266 
 fi-730 
 
 0955 
 
 (-389 
 
 o-ioo 
 
 6-019 
 
 0-854 
 2-240 
 0-0*6 
 8-985 
 
 2-701 
 0-264 
 0-137 
 6-944 
 
 0-659 
 0-327 
 0-123 
 7-245 
 
 Quinovic acid . 
 Quinotannic acid 
 Cinchona-red 
 
 0-196 
 0-9C4 
 0-933 
 7-729 
 
 0222 
 3-179 
 4-384 
 9-933 
 
 1-736 
 0-515 
 
 27'088 
 
 0-684 
 3-362 
 0-722 
 16*355 
 
 0-679 
 2-162 
 0-705 
 27*345 
 
 Cellulo-e 
 
 S9 146 
 
 47*777 
 
 25-459 
 
 45-522 
 
 32-653 
 
 Total of organic constituents 
 Inorganic constituents . 
 
 77-604 
 1-634 
 
 74-224 
 1-661 
 
 68-514 
 2-513 
 
 77-^68 
 1-224 
 
 72-777 
 1-650 
 
 In the bark of Cinchona Calisaya, cultivated in Java, De Vry found ordinary 
 quinine, crystallisable quinine, quinidine, cinchonine, and quinovic acid. The stem- 
 bark was found to contain 3'90 per cent, of quinine and quinidine; the root-bark 
 1-136 of the crude alkaloids; the root-wood 0*06, chiefly cinchonine; the stem-wood 
 0-08, quinine and cinchonine ; the young branches scarcely a trace of alkaloids ; the 
 leaves none. Quinovic acid was found more abundantly in the wood than in the bark ; 
 in greatest quantity in the root-wood, and least in the leaves. The bark of Cinchona 
 lucumcefolia ? yielded only 0-4 per cent, of crude alkaloids. (Handw. d. Chem. ii. [2] 971.) 
 
 CINCHONA-RED. A constituent of cinchona bark, produced from quino- 
 tannic acid by atmospheric oxidation. It may be extracted by boiling the bark with 
 water, treating the residue with .ammonia, and precipitating the ammoniacal filtrate 
 with hydrochloric acid, washing the resulting precipitate of quinovic acid and cinchona- 
 red, and boiling it with thin milk of lime : quinovate of calcium then dissolves, and 
 cinchona-red remains undissolved in combination with lime. The residue, after being 
 washed with water, is treated with hydrochloric acid ; then washed again, dissolved in 
 ammonia, and reprecipitated by hydrochloric acid ; dissolved in alcohol, after another 
 thorough washing ; and the filtrate evaporated to dryness over the water-bath. 
 (Schwarz, Ann. Ch. Pharm. Ixxx. 332.) 
 
 Cinchona-red is an amorphous, chocolate-coloured or red-brown, nearly black mass, 
 almost insoluble in water, easily soluble, with red-brown colour, in alcohol, ether, and 
 alkaline lyes, also in strong acetic acid. It is decomposed by heat, giving off copious 
 red fumes, and yielding by dry distillation, an empyreumatic oil, pyrogallic acid, and 
 an impure, volatile, carmine-coloured, aromatic substance, insoluble in water, but soluble 
 in alcohol, ether, and alkaline liquids. (Boissenot, J. Pharm. [3] xxv. 199.) 
 
 The formula of cinchona-red is C 6 H 7 3 ' 5 , according to Schwarz ; C 7 H 8 8 according to 
 Boissenot ; it is doubtful whether it has ever been obtained pure. The bark of Cin- 
 chona lanci folia (Mutis) contains, according to Reichel, from 1 to 2-5 per cent, of it; 
 other cinchona barks are said to contain a larger amount. 
 
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CINCHONA-TANNIC ACID - CINCHONIDINE. 971 
 
 eXHTCHOWA-TAWBTIC ACID. Syn. with QUINOTANNIC ACID. 
 
 CIWCKONETIJJE. A product of the decomposition of cinchonine by peroxide 
 of lead (p. 974). 
 
 CUCTCHOXTZCIKTZ:. C 20 H 21 N 2 0. (Pasteur, Compt. rend, xxxvii. 119; Chem. 
 Soc. Qu. J. vi. 273.) An alkaloid isomeric with cinchonine, and produced from it 
 under the influence of heat. Any salt of cinchonine may be transformed into the 
 corresponding cinchonicine-salt by heat ; but to make the transformation complete and 
 prevent decomposition, the heat must be moderate and the salt must be kept for some 
 time in a resinous state. The change takes place most easily with the sulphate, which, 
 when mixed with a small quantity of water and sulphuric acid, remains melted at a 
 very moderate heat, even after all the water has been expelled, and if kept in this 
 state for three or four hours between 120 and 130 C., is completely converted into 
 sulphate of cinchonicine. Pasteur is of opinion that the resinous state of the fused 
 sulphate is essential to the molecular transformation which takes place. The base 
 may be separated from the sulphate by precipitation with an alkali. 
 
 Cinchonicine is nearly insoluble in water, but very soluble in alcohol, whether anhy- 
 drous or of ordinary strength. It is very bitter, and is precipitated from its solutions in 
 the form of a liquid resin. It deflects the plane of polarisation to the right. It unites 
 easily with carbonic acid, and separates ammonia from its salts at ordinary temperatures. 
 It possesses febrifuge properties. It is distinguished from cinchonidine by its action on 
 polarised light, and by not being crystallisable ; from cinchonine also by the latter 
 property, and by its much greater solubility in alcohol, and greater bitterness. 
 
 CINCHOariDINE. C 20 H 24 N 2 0, or C 18 H- 2 N 2 0? (Winckler, Eepert. Pharm. 
 [2] xlviii. 384; xlix. 1. Leers, Ann. Ch. Pharm. Ixxii. 147. Pasteur, Compt. 
 rend, xxxvi. 10; xxxvii. 110; Chem. Soc. Qu. J. vi. 275. Bussy and Guibourt, 
 J. Pharm. [3] xxii. 401.) This alkaloid was discovered by Winckler in a bark re- 
 sembling the Huamalies cinchona-bark, also in that of Maracaibo. It has likewise 
 been found, accompanied by a small quantity of quinine, in the Bogota cinchona-bark 
 (p. 965). According to Pasteur, it is isomeric with cinchonine, (C 20 H 24 N 2 0). The 
 German chemists generally give it the name of quinidine. 
 
 Preparation. Cinchonidine is extracted from the barks by the same processes as 
 quinine and cinchonine (pp. 966, 971), and purified by crystallising it several times 
 from alcohol of 90 per cent., till the solution no longer deposits any resinous matter by 
 spontaneous evaporation ; then reducing the crystals to fine powder; agitating with ether 
 till the powder no longer exhibits with chlorine-water and ammonia, the peculiar green 
 colouring produced by quinine and quinidine ; and finally, recrystallising from alcohol. 
 (See also Zimmer's method of separation, p. 967.) 
 
 Properties. Cinchonidine separates from its alcoholic solution by slow evaporation 
 in anhydrous rhombic prisms, of 94, hard, with vitreous lustre, and having their faces 
 deeply striated. The same striae are observed on the faces which replace the obtuse edges 
 of the prism, and the crystals cleave perfectly in the direction of these faces. The 
 prism is modified by two brilliant faces, Poo inclined at an angle of 114 30', and 
 resting on the acute edges. The crystals are easily reduced to a perfectly white pow- 
 der, which becomes electric by friction. They do not taste so bitter as quinine. 
 
 Cinchonidine is very sparingly soluble in water, 1 pt. of it dissolving in 2180 pts. of 
 water at 17 C., and in 1858 pts. at 100. It dissolves in 12 pts. of alcohol of sp. gr. 
 0-835 at 17 ; ether dissolves but little of it, 100 pts. of the solution containing only 
 070 pts. of cinchonidine. (Leers.) 
 
 A solution of cinchonidine in absolute alcohol at 13 C., deflects the plane of polari- 
 sation of a ray of light strongly to the left ; [a] = 144-61. (Pasteur.) 
 
 According to the analyses of Leers, cinchonidine contains from 76-40 to 76*88 per 
 cent, carbon, 7'70 7*81 hydrogen, and 9'99 nitrogen, whence Leers deduced the for- 
 mula C 18 H 22 N 2 0, requiring 76-60 per cent, C, 7'80 H, and 9-93 N, whereas the formula 
 of cinchonine, C 20 H 24 N 2 0, requires 77'9 C, 7'79 H, and 9'09 N. Nevertheless, Pasteur 
 regards cinchonidine as isomeric with cinchonine, inasmuch as it is transformed into 
 cinchonicine by heat, without alteration of weight, in the same manner as cinchonine. 
 
 Decompositions. Cinchonidine melts at 175 C., and solidifies in a crystalline mass 
 on cooling. When strongly heated in contact with the air, it burns with a smoky flame, 
 giving off an odour like that of bitter-almonds or quinine, and leaving a considerable 
 quantity of charcoal. Distilled with hydrate of potassium and a small quantity of 
 water, it yields the same mixture of volatile bases as cinchonine (p. 869). When 
 diffused in fine powder through chlorine-water, it dissolves without perceptible change, 
 even after addition of ammonia. 
 
 Commercial cinchonidine is often contaminated with quinidine, the presence of 
 which may be detected either by the green colouring produced by chlorine and am- 
 monia, or by exposing the recently deposited crystals to the air ; the crystals of qui- 
 nidine then effloresce without losing their form, assuming a dull white appearance, 
 while the crystals of cinchonidine retain their transparency. 
 
972 CINCHONIDINE. 
 
 The Salts of Cinchonidine are for the most part more soluble in water than those 
 of quinine; they are very soluble in alcohol, but nearly insoluble in ether. The 
 aqueous solution yields with alkalis and their carbonates, white pulverulent precipi- 
 tates, which become crystalline when left at rest ; and are insoluble in excess of the 
 reagent. With phosphate of sodium, mercuric chloride, and nitrate of silver, they 
 produce white precipitates ; light yellow with chloride of gold, orange-yellow with 
 dichloride of platinum, and brown with chloride of palladium. With sulphocyanate 
 of ammonium they yield a white, and with tannin, a dirty yellow precipitate. 
 
 HYDEOCHLOBATES OF CINCHONIDINE. The neutral salt, C 20 H 24 N 2 O.HC1 (at 100 C.), 
 forms large rhomboi'dal prisms, having a vitreous lustre, soluble in 27 pts. of water at 
 17 C., very soluble in alcohol, nearly insoluble in ether. 
 
 Analysis (mean). Calculation. 
 
 Leers. Leers. Gerhardt. 
 
 At 100 C. C 18 H*-'N 2 O.HCl.aq. C 20 H* 4 N 2 O.HC1. 
 Carbon . . . 64-34 64-19 69-67 
 
 Hydrogen . . 7'17 7'13 6-97 
 
 Chlorine . . 10-05 10-54 10'31 
 
 The acid salt, C 20 H 84 N 2 O.HC1 + aq., forms large crystals, very soluble in water and 
 in alcohol; after drying over oil of vitriol, they give off 5 '8 per cent, water; the cal- 
 culated quantity for 1 at. is 5-1, according to Leers' formula ; 4-5 according to that 
 proposed by Gferhardt. 
 
 Analysis (mean). Calculation. 
 
 Leers. Leers. Gerhardt. 
 
 At 100 C. C 18 H 22 N 2 0.2HC1. C 20 H 24 N 2 O.HC1. 
 58-30 57-93 63-32 
 
 7-12 6-97 6-33 
 
 18-98 18-99 18-73 
 
 Chloromercurate of Cinchonidine, C 20 H 24 N 2 0.2(HCl.HgCl)? crystallises in 
 shining nacreous scales, sparingly soluble in cold water. Analysis gave 3477 percent. C, 
 4-01 H, 31-9 Hg, and 22-46 01, agreeing nearly with C 18 H"N 2 0.2(HCl.HgCl), which 
 requires 34-52 C, 3'83 H, 31-97 Hg, and 22-63 01. The formula C 20 H 24 N 2 0.2(HC1. 
 HgCl) would require 35'8 C, 3'51 H~ 29-8 Hg, and 21-18 01. 
 
 The chloroplatinate, C 20 H 24 N 2 O.HCl.PtCl 2 ? is an orange-coloured precipitate, 
 containing at 110 C. from 27'05 to 27'17 per cent platinum, whence Leers deduces the 
 formula C l8 H az N 2 O.H01.PtCl > + 2aq., requiring 27'04 per cent. Pt, whereas Gerhardt 
 proposes C 20 H 24 N 2 O.HCl.PtCl 2 , which requires 27'36 per cent. It is not probable that 
 the salt should retain 2 at. of water at 110 C. 
 
 CHLORATE OF CINCHONIDINE, obtained by decomposing the neutral sulphate with 
 chlorate of potassium, crystallises from alcohol in long silky prisms, grouped in tufts. 
 It melts at a gentle heat, and decomposes with loud explosion at a higher temperature. 
 
 HYDROFLUATE OF CINCHONIDINE forms silky needles, very soluble in water. 
 
 HYPOSULPHITE OF CINCHONIDINE, obtained by precipitating the neutral sulphate 
 with hyposulphite of sodium, crystallises on cooling, in long asbestos-like needles, 
 sparingly soluble in water, easily in alcohol. 
 
 NITRATE OF CINCHONIDINE is obtained in mammellated crusts, having the appear- 
 ance of enamel, and very soluble in water. 
 
 SULPHATES OF CINCHONIDINE. The neutral salt, 2C 20 H 24 N 2 O.H 2 S0 4 (at 100 C.), 
 crystallises in long silky needles grouped in stars, neutral to test-paper. One pt. of 
 the salt dissolves in 130 pts. water at 17 C., and in 16 pts. at 100 ; it is very soluble 
 in alcohol, nearly insoluble in ether (Leers); it dissolves at mean temperatures in 
 3032 pts. absolute alcohol, and in 7 pts. alcohol of 90 per cent. (Bussy and 
 G-uibourt.) 
 
 Analysis (mean). Calculation. 
 
 Leers. Leers. Gerhardt. 
 
 At 100 C. 2C 18 H 22 N 2 O.H 2 S0 4 2C ?0 H 24 N 2 O.H 2 S0 4 
 
 64-75 65-25 67'20 
 
 7-05 6-95 6-72 
 
 12-01 12-08 11-20 
 
 The acid sulphate is obtained by evaporation in vacuo, as a crystalline mass com- 
 posed of shining asbestos-like needles. 
 
 Sulphate of lodocinchonidine. Cinchonidine forms with iodine and sul- 
 phuric acid, a crystalline salt, which acts upon light in the same manner as the corre- 
 sponding salts of quinine and cinchonine, also two other salts, one yellow and the 
 other olive-green, which do not exhibit these peculiar optical properties. (W. B. Hera- 
 path, Chera. Soc. Qu. J. xi. 130.) 
 
CINCHONINE. 973 
 
 Acetate of Cinchonidine crystallises in long silky needles, which are very 
 sparingly soluble in cold water, and give off part of their acid on drying. The butyrate 
 and valerate form mammellated crusts, having the odour of the respective acids. 
 
 The citrate forms small needles, having but little lustre. The hippurate crys- 
 tallises in silky needles, having the aspect of fern-leaves, very soluble in water and 
 alcohol. The oxalate separates on cooling in long silky needles, from a mixture of 
 the hot alcoholic solutions of oxalic acid and cinchonidine. The mother-liquor depo- 
 sits by spontaneous evaporation, dull white, mammellated crusts. The quinate crys- 
 tallises in small needles, very soluble in water and in alcohol. The neutral tart rate 
 forms beautiful needles, having a vitreous lustre. The acid tartrate forms small 
 nacreous needles, very sparingly soluble in water. 
 
 METHYL-CINCHONIDINE, C I8 H 21 (CH 3 )N 2 0, or C 20 H 23 (CH 3 )N 2 ? (Stahlschmidt, 
 Ann. Ch. Pharm. xc. 218.) The hydriodate of this base is obtained by the action of 
 iodide of methyl on cinchonidine. It crystallises in colourless shining needles, con- 
 taining : 
 
 Sy Analysis. By Calculation. 
 
 At 100 C. C 18 H 21 (CH 3 )N 2 O.HI C 20 H 23 (CH 3 )N 2 O.HI. 
 
 Carbon . . 53-87 5376 56-1 
 
 Hydrogen . 5'92 5-89 6-0 
 
 Iodine . . 29-84 29-87 28-0 
 
 Oxide of silver converts it into a basic compound resembling methyl-cinchonine. 
 
 OITJCHONINE. C 20 H 2 'N 2 0, or C*H U N*0'*. (Fourcroy, Ann. Chim. viii. 113 ; 
 ix. 7. Vauquelin, ibid. lix. 30, 148. Gromez, Edinb. Med. and Surg. Journal, 1811, 
 Oct. p. 420. Pfaff, Schw. J. x. 365. Pelletier and Caventou, Ann. Ch. Phys. 
 xv. 291, 337. Pelletier and Dumas, ibid. xxiv. 169. Liebig, Ann. Ch. Pharm. 
 xxvi. 49. Eegnault, Ann. Ch. Phys. Ixviii. 113. G-erhardt, Eev. scient. x. 886; 
 Traite, iv. 105. Laurent, Ann. Ch. Phys. [3] xix. 363. Strecker, Compt. rend. 
 xxxix. 58.) 
 
 This alkaloid exists, together with quinine, in most of the true cinchona-barks, most 
 abundantly in Cinchona Huanoco, C. Huamalies, C. rubiginosa, and C. flava fibrosa. 
 (See table, p. 968.) 
 
 Preparation. All methods of extracting the alkaloids from cinchona-barks consist in 
 treating the bark with a dilute acid, and precipitating the alkaloids from the acid extract, 
 with lime or carbonate of sodium, The general mode of proceeding is as follows : 
 
 The bark, reduced to powder, is boiled for an hour or less with 8 or 10 times its 
 weight of water, acidulated with 10 per cent, of strong sulphuric acid, or better, with 
 25 per cent, of hydrochloric acid ; the decoction is strained through a cloth ; and the 
 residue is boiled a second and sometimes a third time, with more and more dilute acid 
 till the marc is completely exhausted. The extracts, after cooling, are mixed with a 
 slight excess of milk of lime, added by small portions, to precipitate the alkaloids together 
 with the colouring matter. The precipitate is left to drain, and submitted to a gradu- 
 ally increasing pressure, the liquids which run off from the cloths and from the press 
 being collected in a single vessel ; they yield after a while a fresh deposit. The pressed 
 cake is now dried, and macerated with alcohol in a closed vessel heated over a water- 
 bath. The strength of the alcohol used depends upon the quality of the bark under 
 treatment. For Calisaya bark, which is very rich in quinine, alcohol of 75 to 80 per 
 cent, is sufficiently strong ; but barks which contain a smaller proportion of quinine, 
 require alcohol of 85 to 90 per cent., because cinchonine is much less soluble in weak 
 alcohol than quinine. 
 
 If the bark is rich in cinchonine, and the quantity of alcohol used is not too large, 
 the cinchonine is deposited in the crystalline state as the alcoholic extracts cool, and 
 an additional quantity may be obtained by decanting the supernatant liquid, and dis- 
 tilling off half or two-thirds of the alcohol. The quinine remains in the mother- 
 liquor and may be separated in the form of sulphate. (See QUININE.) 
 
 If on the other hand the bark contains more quinine than cinchonine, it is best to 
 treat the alcoholic extract with dilute sulphuric acid, and remove the alcohol by 
 distillation. The greater part of the sulphate of quinine then separates in a crystal- 
 line mass, the rest, together with the sulphate of cinchonine, remaining in the mother- 
 liquor. By precipitating the two alkaloids with carbonate of sodium, redissolving in 
 sulphuric acid, and recrystallising, a further separation may be effected ; or they may 
 be precipitated by a caustic alkali, and separated by ether, which dissolves the quinine 
 much more readily than the cinchonine (p. 966). 
 
 Carbonate of sodium is a better precipitant for the alkaloids than lime, because they 
 are soluble to a slight extent in lime-water and chloride of calcium. 
 
 Oil of turpentine, fixed oils, and chloroform may be used instead of alcohol for dis- 
 solving the alkaloids from the crude precipitate thrown down by lime or soda; and 
 
974 CINCHONINE. 
 
 these solvents have the advantage of not taking up so much of the colouring matter as 
 alcohol does (p. 966) ; but they are better adapted for the preparation of quinine than 
 of cinchonine, which is but sparingly soluble in either of them. (See QUININE.) 
 
 Properties. Cinchonine deposited by slow evaporation of its alcoholic solution, 
 forms colourless, shining, quadrilateral prisms or needles, which are anhydrous. It 
 has a peculiar bitter taste, which however is slow in developing itself, on account of 
 the sparing solubility of the substance. It is insoluble in cold water, and requires for 
 solution 2500 parts of boiling water. In alcohol it is much less soluble than quinine, 
 the solubility increasing however with the strength of the alcohol and the temperature. 
 According to Duflos, strong alcohol dissolves 3 per cent of its weight of cinchonine. 
 It is insoluble in ether, slightly soluble in chloroform, volatile oils and fixed oils. 
 
 The solutions of cinchonine have an alkaline reaction, and deflect the plane of 
 polarisation of a luminous ray strongly to the right. An alcoholic solution acidulated 
 with sulphuric acid gives [a] = + 190-40 ; acids produce a temporary decrease of 
 the rotatory power. Cinchonine possesses febrifuge properties, but in a much lower 
 degree than quinine. 
 
 The following are the mean results of the analyses of cinchonine by various chemists. 
 
 Calculation. Liebig. Regnault. Gerhardt. Hlasiwetz. Laurent. 
 
 C 2 . . 240 77-93 76-36 7678 77'63 77'97 77' 29 
 
 N24 . . 24 7-79 7-37 7'69 7'98 775 768 
 
 N2 . .28 9-09 8-87 9'45 _ _ 
 
 O . 16 5-19 7-40 6-08 __ _ _ 
 
 C-H!MN2O 308 100-00 10000 10000 
 
 Laurent assigned to cinchonine the formula C 19 H 22 N 2 0. According to Schiitzen- 
 berger (Jahresber. d. Chem. 1858, p. 372), the name cinchonine is applied to bases 
 of different constitution ; one sample which he analysed yielded numbers agreeing with 
 the formula C 18 H 22 N 2 2 . 
 
 Cinchonine melts at 165 C. forming a colourless liquid, which becomes crystalline 
 on cooling ; at a higher temperature, it partly sublimes, exhaling an aromatic odour. 
 According to Hlasiwetz, cinchonine may be sublimed in hydrogen or ammonia gas 
 in the form of shining prisms more than an inch long. Heated with sulphuric acid 
 and peroxide of lead, it yields a red substance, cinchonetine, which has not been 
 examined (Marchand, J. Chim. me"d. x. 362). Other oxidising agents, e.g. nitric 
 acid, permanganate of potassium, and a mixture of sulphuric acid and peroxide of 
 manganese, do not exert much action upon it; neither is it decomposed in a definite 
 manner by emulsin (Hlasiwetz). With nitrous acid, it forms a base containing 
 1 at. oxygen more than cinchonine, and isomeric with quinine, but approaching more 
 nearly to cinchonine in its properties (Schutzenberger, Jahresber. d. Chem. 1858, 
 p. 371). It dissolves in fuming sulphuric acid, yielding sulpho-cinchonic acid, 
 which forms a soluble barium-salt, C 20 H 23 BaN 2 O.S0 4 (Schutzenberger.) With chlo- 
 rine and bromine, it forms several substitution-bases, as well as a resinous substance. 
 With chlorine and ammonia, it does not exhibit the green colouring which is charac- 
 teristic of quinine. With iodine and iodated potassic iodide it behaves like quinine. 
 Distilled with hydrate of potassium, it yields chinoline, together with several other 
 volatile bases (p. 869). 
 
 Beta-cinchonine. Schwabe (J. Pharm. [3] xxxviii. 389), has obtained from 
 commercial quinoi'dine (a product of the alteration by heat of quinine, cinchonine, &c. 
 found in the mother-liquors of the preparation of sulphate of quinine), an alkaloid 
 isomeric with cinchonine, but differing from it in many properties. This /8-cinchonine 
 is contained in the portion of quinoi'dine which is sparingly soluble in alcohol ; and the 
 sulphate is obtained therefrom by dissolving the substance in dilute acid, precipitating 
 with ammonia, treating the washed precipitate with cold alcohol of specific gravity 0'845, 
 again dissolving it in dilute sulphuric acid, and crystallising. The base separated 
 from the sulphate crystallises from boiling alcohol by spontaneous evaporation in 
 rhombic combinations, ooP. oof oo. oP ( ooP : ooP = 119). The crystallised as 
 well as the precipitated base is anhydrous, and melts at 150 C. /3-cinchonine is 
 more soluble in water, alcohol, ether, and chloroform than ordinary a-cinchonine. 
 The following table gives the quantities of these several solvents required to dissolve 
 1 pt. of a and & cinchonine, as determined by Schwabe. 
 
 a.- Cinchonine. &- Cinchonine. 
 
 Water, cold insoluble insoluble 
 
 Water, hot . . . . . 2500 scarcely soluble 
 
 Alcohol, cold _ 173 
 
 Alcohol, hot 30 43 
 
 Ether insoluble 378 
 
 Chloroform 40 268 
 
CINCHONINE. 975 
 
 The alcoholic solution of j8-cinchonine is dextro-rotatory. ^ 
 
 /J-cinchonine is precipitated white from the solutions of its salts by caustic or car- 
 bonated alkalis, the precipitate being somewhat soluble in excess of the reagent, and 
 disappearing when shaken up with ether. A solution of the base containing tartario 
 acid is not precipitated by acid carbonate of sodium. A neutral solution of the sul- 
 phate mixed with chlorine-water and then carefully with ammonia, exhibits a yellow 
 colour. With ferrocyanide of potassium and chlorine, a red colouring is produced, 
 turning green on addition of ammonia. Quinine-solutions thus treated, exhibit a dark 
 red colour ; ordinary cinchonine and quinidine, wine-yellow. 
 
 Salts of Cinchonine. Cinchonine dissolves readily in acids. The salts are 
 bitter and are very much like the corresponding salts of quinine, but for the most part 
 more soluble in water and in alcohol. Ordinary cinchonine forms both acid and 
 neutral salts ; /8-cinchonine apparently only neutral salts. 
 
 ACETATE OF CINCHONIKE. A solution of cinchonine in acetic acid always exhibits 
 an acid reaction, however great may be the excess of cinchonine contained in it ; but 
 if concentrated by heat, it deposits on cooling, small sparingly soluble crystals, which 
 exhibit no acid reaction after washing. If the liquid be slowly evaporated to dryness, 
 a gummy mass is obtained, which is decomposed by water into an acid salt which 
 dissolves and a neutral salt which remains at the bottom. (Pellet ier and Ca- 
 ventou.) 
 
 Acetate of ^-Cinchonine forms right-angled four-sided prisms, like those of the 
 sulphate and hydrochlorate. (Schwabe.) 
 
 AESENATE of CINCHONINE. Very soluble; difficult to crystallise. 
 
 CARBONATE OF CINCHONINE. Cinchonine dissolves in aqueous carbonic acid more 
 easily than in pure water ; but the solution does not yield a crystallised carbonate. 
 
 CHLORATE of CINCHONINE, C 20 H 24 N 2 O.HC10 3 . White bulky crystalline tufts; melts 
 at a gentle heat, and decomposes with explosion at a higher temperature. (Serullas.) 
 
 CHROMATE OF CINCHONINE. Obtained as a yellow amorphous precipitate, adhering 
 to the glass, but becoming crystalline after a while when a solution of sulphate of 
 cinchonine is mixed with acid chromate of potassium. It is decomposed by water and 
 alcohol. (Elderhorst.) 
 
 CYANURATE OF CINCHONINE. A solution of cinchonine in a boiling saturated so- 
 lution of cyanuric acid deposits rhomboidal prisms, sparingly soluble in water, inso- 
 luble in alcohol and ether. The salt gives off 17'79 per cent, water at 100 C; and 
 decomposes at 200, exhaling an odour of bitter almonds. (Elderhorst.) 
 
 FERRICYANATE OF CINCHONINE, C 20 H 24 N 2 0.3HCy.Fe 2 Cy 3 + 2aq. Orange-yellow pre- 
 cipitate, obtained by mixing the aqueous solutions of hydrochlorate of cinchonine and 
 ferricyanide of potassium. After drying in the air, it undergoes no alteration at 100 C. 
 (Dollfus, Ann. Ch. Pharm. Ixv. 224.) 
 
 FERROCYANATE OF CINCHONINE, C 20 H 24 N 2 0.4HCy.2FeCy + 2aq. Lemon-yellow pre- 
 cipitate produced on mixing the alcoholic solutions of cinchonine and ferrocyanic acid. 
 It is very sparingly soluble in alchol, and when heated, either alone, or with water, is 
 decomposed, yielding hydrocyanic acid and a blue residue (Dollfus). Ferrocy- 
 anate of ^-cinchonine is sparingly soluble and cry stallisable. (Schwabe.) 
 
 FORMATE OF CINCHONINE. Very soluble; crystallises from a syrupy solution in 
 silky needles. 
 
 GALLOTANNATE OF CJNCHONINE. Yellowish-white powder, very little soluble in cold, 
 more soluble in boiling water, whence it separates in transparent grains on cooling. 
 
 HIPPURATE OF CINCHONINE. Uncrystallisable. 
 
 HYDROCHLORATE OF CINCHONINE. Theneutral salt, C 20 H 24 N 2 O.HC1, obtained by 
 exactly saturating cinchonine with weak hydrochloric acid ; crystallises in transparent 
 shining rhomboidal prisms ; melts at 100 C. ; dissolves easily in water and in alcohol, 
 but is insoluble in ether. The aqueous solution possesses dextro-rotatory power; 
 [a]= +139-50 (Bouchardat). When subjected to electrolysis, it yields chloro- 
 cinchonine, together with chlorine, oxygen, and hydrogen. (Babo.) 
 
 Hydrochlorate of ^-cinchonine, C 20 H 24 N 2 O.HC1 + 2aq., crystallises apparently 
 in rhombic combinations, ooP . ooP oo . oP, in which o>P: a>P = 126|. It dissolves 
 in 22 pts. of cold, 3 '2 pts. of hot water; in 1 pt. of cold, | pt. of boiling alcohol, and 
 in 550 pts. of ether. 
 
 Acid hydrochlorate of cinchonine, C 20 H 24 N 2 0.2HC1, is produced by exposing 
 cinchonine to hydrochloric acid gas, and is obtained crystallised by pouring a slight 
 excess of the acid on cinchonine, and dissolving the product in a mixture of water and 
 alcohol. The solution left to evaporate very slowly in an unclosed bottle, deposits 
 very well-defined rhombic tabular crystals, having the acute angles truncated, 
 ooP : >P = 101; Poo : oP = 137 to 138. It is very soluble in water, rather 
 less in alcohol ; reddens litmus. The solution is dextro-rotatory. 
 
976 CINCHONINE. 
 
 Chlorine passed into a solution of this salt, forms a deposit of acid hydrochlorate of 
 dichlorocinchonine. 
 
 Chloromercurate, C 20 H- 4 N 2 0.2(HCl.HgCl). On mixing a solution of cinchpnine 
 in strong alcohol containing hydrochloric acid with a solution of mercuric chloride also 
 in strong alcohol, the mixture solidifies after a while to a mass of small needles, nearly 
 insoluble in cold water, ordinary alcohol, and ether, moderately soluble in boiling 
 water, and in warm alcohol, easily soluble in strong hydrochloric acid. The salt may 
 be dried at 100 C. without alteration. 
 
 Chloroplatinate, C 20 H 24 N 2 0.2(HCl.PtCl 2 ). Light yellow precipitate, obtained by 
 adding dichloride of platinum to a solution of acid hydrochlorate of cinchonine. ^ With 
 an alcoholic solution of cinchonine containing hydrochloric acid, the precipitate is crys- 
 talline and nearly white, and dissolves after prolonged boiling with water, the solution 
 as it boils, depositing, first a whitish pulverulent precipitate, afterwards beautiful crystals 
 of a deep orange colour. The salt contains, according to Hlasiwetz, 33 '1 per cent.C, 
 3-6 H, and 27'36Pt, the formula requiring 33'0 C, 3-3 H, and 27'36 Pt. 
 
 Chloroplatinate of ^-cinchonine, C 20 H 21 N 2 O.HCl.PtCl 2 , crystallises on mixing 
 the alcoholic solutions of its component salts, in rhombic combinations, ooP . oo P co . oP, 
 in which ooP : ooP =.119 (approximately).' (Schwabe.) 
 
 HYDROCYANATE OF JS-CINCHONINE, obtained by precipitation with cyanide of potas- 
 sium, is amorphous, anhydrous, insoluble in water and alcohol. (Schwabe.) 
 
 HYDROFLUATE OF CINCHONINE, C 20 H 24 N 2 0. 2HF. A solution of recently precipitated 
 cinchonine in dilute hydrofluoric acid, deposits colourless prisms when concentrated. 
 The salt crystallises easily from dilute alcohol in rhomboidal prisms terminated by 
 octahedral faces. After drying at mean temperature, it gives off 2*8 per cent, water 
 at 160C.; at a high temperature, it acquires a fine purple tint, yields a red sublimate, 
 gives off hydrofluoric acid, and becomes carbonised. 
 
 HYDRIODATE OP CINCHONINE, C 20 H 24 N 2 O.HI + aq. (Kegnault.) Much less soluble 
 than the hydrochlorate. Crystallises easily in nacreous needles. Its solution is pre- 
 cipitated by mercu ric chloride and cyanide. Hy driodate of ^-cinchonine is easily 
 soluble in water and in alcohol. (Schwabe.) 
 
 HYPOSULPHATE OF CINCHONINE. Crystallisable ; resembles the quiuine-salt (q.v.~) 
 
 HYPOSULPHITE of CINCHONINE. Obtained by precipitation in small needles ; very 
 sparingly soluble in cold water. (Win elder.) 
 
 IODATE OF CINCHONINE, C 20 H 24 N 2 O.HI0 3 (at 1 05 C.). Long silky fibres, very 
 soluble in water and alcohol Explodes with violence at 120 C. 
 
 NITRATE OF CINCHONINE, C 20 H 24 N 2 O.HN0 3 + aq. (Eegnault.) Obtained by dis- 
 solving cinchonine in dilute nitric acid. If the solution is rather concentrated, part 
 of the nitrate separates in oily globules, which, if covered with water, are converted 
 in a few days into a group of oblique rectangular prisms, very soluble in water. The 
 solution is dextro-rotatory, [a] = +172-48 (Bouchardat). When decomposed 
 by the electro- current (from six Bunsen's cells), it gives off oxygen at the positive 
 pole, mixed after a while with carbonic acid and oxides of nitrogen, and at the negative 
 pole, a mixture of hydrogen and nitrogen containing a little ammonia ; in the liquid 
 into which the negative pole dipped, a resinous substance was deposited, and the 
 solution decanted therefrom and distilled with potash, yielded ammonia and oily drops 
 of chinoline. (Babo, J. pr. Chem. Ixxii. 73.) 
 
 Nitrate of ^-cinchonine crystallises slowly, by spontaneous evaporation, in 
 monoclinic or triclinic crystals, which are moderately soluble in water and alcohol, and 
 do not effloresce. (Schwabe.) 
 
 OXALATES OF CINCHONINE. The neutral oxalate is a white precipitate, insoluble 
 in cold, slightly soluble in boiling water, very soluble in alcohol, especially if hot, and 
 in oxalate of ammonium. The acid oxalate is much more soluble than the neutral 
 salt. Oxalate of ^-cinchonine is crystallisable. (Schwabe.) 
 
 OXALURATE OF CINCHONINE. Obtained by saturating a boiling solution of parabanic 
 acid with excess of cinchonine. The solution dries up to a yellowish transparent mass, 
 which whitens a little as it assumes the crystalline form. When boiled with hydro- 
 chloric acid, it dissolves, producing oxalic acid. (Elderhorst.) 
 
 PERCHLORATE OF CINCHONINE, C 20 H 24 N 2 O.HC10 4 + aq. Obtained by decomposing 
 sulphate of cinchonine with perchlorate of barium. Large rhombo'idal prisms, having 
 a strong lustre, and exhibiting a fine blue and yellow dichro'ism, even in very dilute 
 solutions. Very soluble in water and alcohol. Melts and gives off its water at 160 C. 
 and decomposes with explosion at a higher temperature. The salt dried at 30 C. 
 gives off 3-57 per cent, water at 160 (Boedeker, jun. Ann. Ch. Pharm. Ixxi. 59). 
 According to Dauber (ibid. 66), the crystals belong to the diclinic system of Nau- 
 mann (see CRYSTALLOGRAPHY), being rhomboidal prisms of 125 47' and 54 13' with 
 perpendicular truncation of the acute edges. 
 
CINCHONINE. 977 
 
 PERIODATE OF CINCHONINE. Very unstable prisms, obtained like the perchlorate. 
 According to Langlois, periodic acid oxidises cinchonine more rapidly than quinine. 
 
 PHOSPHATE OF CINCHONINE. Very soluble. A solution of cinchonine in phosphoric 
 acid, yields by evaporation, sometimes rudimentary crystals, but more generally amor- 
 phous, transparent plates, which gradually become crystalline by contact with water. 
 
 Phosphate of ^-cinchonine forms crystals nearly a line in length, and appa- 
 rently oblique-angled. (Schwabe.) 
 
 PICRATE OF CINCHONINE. Yellow pulverulent precipitate, nearly insoluble in water, 
 very soluble in alcohol. 
 
 QTJINATE OF CINCHONINE. A strong aqueous solution of cinchonine in quinic acid 
 deposits, when left at rest, sometimes silky needles, sometimes a mammellated mass of 
 small granules. The salt dissolves in half its weight of water at 25 C. : it contains 
 water of crystallisation. From a solution in warm alcohol, it crystallises on cooling in 
 colourless, shining, short, compressed prisms, apparently unalterable either by ex- 
 posure to the air or by a moderate heat, but becoming completely opaque in course of 
 time. Water dissolves them very readily, but with partial decomposition. Their 
 aqueous solution turns reddened litmus blue, but the alcoholic liquid from which they 
 were deposited, turns blue litmus red. 
 
 SULPHATES OF CINCHONINE. The neutral sulphate, 2C 20 H 24 N 2 O.H 2 S0 4 + 2 aq., is 
 obtained by exactly saturating cinchonine with dilute sulphuric acid. It forms rhombic 
 prisms of 83 and 97, generally very short, and having their ends truncated or 
 bevelled : cleavable parallel to the prismatic faces ; sometimes hemi tropic. They are 
 hard, transparent, and have a vitreous lustre ; permanent in the air ; melt a little 
 above 100 C. and give off their 2 at. water between 100 and 120. They dissolve at 
 mean temperatures in 54 pts. water, 6^ pts. alcohol of specific gravity 0'85, and 11^ pts. 
 absolute alcohol; insoluble in ether (Baup). It is but slightly decomposed by the 
 electric current. 
 
 Sulphate of cinchonine becomes phosphorescent at 100 C. like sulphate of quinine. 
 At higher temperatures, it melts and then decomposes, yielding a resinous matter of a 
 fine red colour. But if the salt be previously mixed with a little water and sulphuric 
 acid, it remains liquid at a low temperature, even after all the water has been driven 
 off; and if kept in this state for three or four hours at 120 to 130 C. it is completely 
 transformed into sulphate of cinchonicine, only a very small quantity of colouring 
 matter being then produced. (Pasteur, p. 969.) 
 
 Sulphate of ^-cinchonine, 2C 20 H 24 N 2 O.H 2 S0 4 + 2 aq. Crystallises in rhombic 
 combinations oo P . oo P oo . o P, in which oo P : oo P= 136. It dissolves in 75 pts. of 
 cold, and 14 pts. of hot water; in 13'6 pts. of cold, and 1-5 pts. hot alcohol of 80 per 
 cent., and is insoluble in ether. The dilute aqueous solution is strongly iridiscent. 
 (Schwabe.) 
 
 Acid Sulphate of Cinchon in e, C 20 H 24 N 2 p.H 2 S0 4 + 3 aq. By adding sulphuric 
 acid to the neutral sulphate, and evaporating till a slight pellicle is formed, the acid 
 salt is obtained in rhombic octahedrons, often having some of their edges or summits 
 modified, and cleaving very easily, at right angles to the axis, in well-defined shining 
 laminae. It is permanent in the air at ordinary temperatures, but effloresces in very 
 dry air or if slightly warmed. When heated, it gives off 1173 per cent, water = 3 at. 
 At 14 C., 100 pts. of the salt [? anhydrous or hydrated], dissolve in 45 pts. water, in 
 90 pts. of alcohol, of specific gravity 0'85, and in 100 pts. of absolute alcohol : it is 
 insoluble in ether. (Baup, Ann. Ch. Phys. [3] xxvii. 323.) 
 
 SULPHOCYANATE OF CINCHONINE, C 20 H 24 N 2 O.HCyS, crystallises in brilliant anhy- 
 drous needles (D o 1 1 f u s). Sulphocyanate of ft - c i n c h o n i n e is also crystallisable. 
 (Schwabe.) 
 
 TAKTBATES OF CINCHONINE. (Pasteur, Ann. Ch. Phys. [3] xxxviii. 456, 469. 
 Arppe, J. pr. Chem. liii. 331.) These salts, neutral and acid, dextro- or leevo-rota- 
 tory, are prepared by dissolving cinchonine in the proper proportions in the two modi- 
 fications of tartaric acid. 
 
 o. Neutral, 2C 20 H 24 N 2 O.C 4 H 6 6 + 2 aq. Large needles grouped in bundles, spar- 
 ingly soluble in water, and giving off their crystallisation- water, 4*6 per cent., between 
 100 and 120 C. (Arppe.) 
 
 )8. Acid Tartrates. The dextro-rotatory salt, C 20 H 24 N 2 O.C 4 H 6 6 + 4aq., forms 
 nacreous shining crystals grouped in radiate stars. They belong to the trimetric 
 system, and are often hemihedral. Observed combination, oo P . P oo . P. Inclination of 
 
 faces, oo P : oo P = 133 20' (nearly); Poo: Poo = 127 40'; ?:$ oo = 151 13'. The 
 
 faces oo P are longitudinally striated. It gives off its water (1375 14-0 per cent. : 
 calculation, 13*58 per cent"* at 100 C., and at 120, assumes a red colour and begins 
 VOL. I. 3 E 
 
978 CINCHONINE. 
 
 to melt. It dissolves but sparingly in cold, much more easily in hot water, still more 
 in alcohol ; the solution is neutral to test-paper. 
 
 A solution containing twice the quantity of tartaric acid required to form this salt, 
 deposits at first, another acid tartrate in transparent well-defined crystals. 
 
 Lcevo-rotatory acid tartrate, C 20 H 24 N 2 O.C 4 H 6 6 + aq. This salt gives off its 
 water = 4-58 per cent. (calc. 378), at 100 C. It is very sparingly soluble in alcohol 
 and in water; the alcoholic solution is neutral, the aqueous solution acid to test-paper. 
 
 If a g^eat excess of acid is used in the preparation, another acid tartrate is obtained 
 crystallised in brilliant tufts, composed of very slender needles, and very different in 
 appearance from the second dextro-rotatory acid tartrate above-mentioned. (Pasteur.) 
 
 UEATE OF CINCHONINE, C 20 H 24 N 2 O.C 5 H 4 N 4 S + 4 aq. Obtained by boiling uric acid 
 with cinchonine recently precipitated and diffused through a large quantity of water. 
 The liquid filtered at the boiling heat, deposits long prisms sparingly soluble in water, 
 boiling alcohol, and ether. On heating the salt to 100 C. or leaving it to evaporate 
 over oil of vitriol, it becomes opaque, and finally assumes a sulphur-yellow colour, 
 giving off 12-49 per cent. (calc. 4 at. = 1373 per cent). During the desiccation, it is 
 in a state of constant agitation, and is finally converted into a crystalline powder, 
 probably differing in form from the hydrated crystals. (Elderhorst, loc.cit.) 
 
 Brominatcd, Chlorinated, and lodated Derivatives of Cinchonine. 
 
 BROMOCINCHONINE, C 20 H S3 BrN 2 0. (Laurent, Ann. Ch. Phys. [3] xxiv. 302.) 
 When bromine is poured upon moist acid hydrochlorate of cinchonine, a product is 
 obtained, which, when freed from excess of bromine by washing with a little alcohol, is 
 a mixture of acid hydrobromate or hydrochlorate of bromocinchonine and sesquibromo- 
 cinchonine. On treating it with boiling alcohol, the former of these salts dissolves, 
 while the latter is nearly insoluble ; and on adding ammonia to the decanted solution, 
 boiling to expel part of the alcohol, and leaving it to cool, bromocinchonine is depo- 
 sited in laminae, which may be purified by recrystallisation. 
 
 The acid hydrochlorate, C 20 H 23 BrN 2 0.2HCl, crystallises in the same form as the 
 corresponding salt of cinchonine. The chloroplatinate, C 20 H 23 BrN 2 0.2(HCl.PtCl 2 ), 
 is a pale yellow powder, containing at 50 C. 24-2 per cent, platinum (calc. 2475). 
 
 SESQUIBROMOCINCHONINE, C 20 H 22 ' 6 Br 1>5 N 2 0. (Laurent, loc. cit.} When the 
 pulverulent residue, insoluble in boiling alcohol, obtained in the preparation just 
 described, is boiled with water, and ammonia added, a white bulky precipitate of sesqui- 
 bromocinchonine is formed, which, after washing and drying, dissolves in boiling alco- 
 hol, and crystallises therefrom in slender needles. It is slightly bitter ; its alcoholic 
 solution turns reddened litmus blue. It melts when heated, afterwards blackens with 
 intumescence. It gives by analysis 55'45 per cent. C, 5-18 H, and 28'3 Br, the formula 
 requiring 56-270, 5-27H, and 28-13 Br. 
 
 The acid hydrochlorate, C^H^Br^N'O^HCl, forms rhombic tables, in which 
 oo P: ooP = 107 to 108. 
 
 The hydrobromochlorate, C3*H ll *Br I '*N a O.HCLHBr, is obtained by pouring 
 bromine on hydrochlorate of cinchonine ; boiling with alcohol as above, to remove hy- 
 drochlorate of bromocinchonine ; again pouring alcohol on the residual salt ; boiling ; 
 adding ammonia, which dissolves it immediately; then adding excess of hydrochloric 
 acid to the solution, and leaving it to cool. The salt is then deposited in small rhombic 
 tables, in which oo P : oo P = 107 to 108. 
 
 The choroplatinate, C 20 H 22>5 Br 1 - 5 N 2 0.2(IICl.PtCl 2 ), is a very pale-yellow precipi- 
 tate, containing at 100 C. 23*0 per cent, platinum; by calculation, 23-5. 
 
 DIBROMOCINCHONINE, C 20 H 22 Br 2 N 2 0. (Laurent, Compt, chim. 1849, p. 311.) 
 Bromine in excess is poured on acid hydrochlorate of cinchonine, to which a little water 
 has been added ; the product is heated when the action is over, to complete the bro- 
 mination of the cinchonine, and expel excess of bromine ; water is then poured upon 
 it ; the liquid is boiled and filtered ; alcohol is added to the aqueous filtrate, heat again 
 applied, and the solution is neutralised with ammonia. On cooling, it deposits dibromo- 
 cinchonine in colourless laminae, with nacreous reflexion. 
 
 Dibromocinchonine is insoluble in water, sparingly soluble in boiling alcohol. At 
 about 200 C. it swells, blackens, and yields a substance which dissolves easily in 
 potash, and is separated therefrom by acids in brown flakes. Dibromocinchonine gives 
 by analysis 51-20 per cent, C, 4'4H, and 34-00 Br, the formula requiring 51-28 C, 
 4-70 H, and 34-19 Br. A solution which had been left for some days in an open 
 vessel, deposited rectangular octahedrons, containing 4 '2 per cent. = 1 at. water of 
 crystallisation. 
 
 The acid hydrochlorate, C 20 H 22 Br 2 N 2 0.2HCl, obtained by treating the base with 
 hydrochloric acid, is sparingly soluble in water, and separates from a boiling solution 
 on cooling, in rhombic tablets, having their four acute angles truncated ; oo P : oo P = 
 
CINCHONINE. 979 
 
 104 to 105 : Poo : oP =137. Its solution deflects the plane of polarisation to the 
 right. 
 
 DICHLOROCINCHONINE, C 20 H 22 C1 2 N 2 0. (Laurent, Ann. Ch.Phys. [3] xxiv. 302.) 
 The acid hydrochlorate of this base is formed by passing chlorine into a hot concen- 
 trated solution of acid hydrochlorate of cinchonine; and on adding ammonia to a 
 solution of this salt in boiling water, the base is precipitated as a light flocculent mass, 
 which crystallises from boiling alcohol in microscopic needles, yielding by analysis 
 18'9 per cent, chlorine (calc. 18 ! 83). 
 
 The acid hydrochlorate, C 20 H 22 C1 2 N 2 0.2HC1, is sparingly soluble in water, and 
 requires 50 pts. of alcohol to dissolve it : the solution is dextro-rotatory. The salt 
 crystallises in rhombic tables isomorphous with the crystals of acid hydrochlorate of 
 cinchonine, oo P : oo P=106 ; Poo : oP = 136 30' to 137 30'. 
 
 The chloroplatinate, C i0 H 22 Cl 2 N 2 O.2(HCl.PtCl 2 ),is a pale yeUow powder, yielding 
 at 100, 25-00 per cent, platinum (calc. 25*06). 
 
 The acid hydrobr ornate, C 20 H 22 Cl 2 N 2 0.2HBr, obtained by treating the base with 
 hydrobromic acid, is sparingly soluble, and crystallises in brilliant laminae, having sensibly 
 the same angles as those of the acid hydrochlorate, but presenting a different appearance, 
 inasmuch as the modifying faces are considerably developed, so that the rhombic tablet 
 is transformed into a six-sided prism ; oo P : oo P = 104 ; P oo : oP = 137. The salt 
 has the same composition as the acid hydrochlorate of dibromocinchonine, but differs 
 from it in giving with nitrate of silver a precipitate of bromide of silver, whereas the 
 latter yields a precipitate of chloride. 
 
 The nitrate is sparingly soluble in water, and crystallises in small elongated tetra- 
 hedrons, formed of four equal scalene triangles, and having their opposite edges trun- 
 cated. 
 
 IODOCINCHONINE, 2C 20 H 24 N 2 O.P (?) (Pelletier, Ann. Ch. Phys. [2] Ixiii. 181.) 
 When cinchonine is triturated with about half its weight of iodine, and the product is 
 treated with alcohol of 36 per cent., the whole dissolves, and on leaving the solution to 
 evaporate, it first deposits the so-called iodocinchonine in saffron-coloured plates, after- 
 wards crystalline nodules of hydriodate of cinchonine. On treating the whole with 
 boiling water, the hydriodate dissolves, and the iodocinchonine separates in the melted 
 state. 
 
 Iodocinchonine has a deep saffron-yellow colour when seen in mass ; its powder is 
 lighter. It has a slightly bitter taste. When heated, it softens at 25 C. but does 
 not enter into complete fusion till heated to 80. It is insoluble in cold water, very 
 soluble in boiling water, soluble in alcohol and ether. It gave by analysis 28'83 per 
 cent, iodine (calc. 29'03). 
 
 Iodocinchonine may be decomposed by the successive action of acid and alkaline 
 solutions. It is likewise decomposed by nitrate of silver. (Pelletier.) 
 
 If the preceding formula be correct, the compound is not iodocinchonine, but iodide 
 of cinchonine. 
 
 Sulphate of Iodocinchonine. (W. B. Herapath, Chem. Soc. Qu. J. xi. 151.) 
 Cinchonine treated with iodine and strong sulphuric acid, yields a crystalline salt, which 
 resembles the corresponding quinine-compound in its action on light. It crystallises in 
 long needles, which appear deep purple-red by transmitted, and dark purple-blue by re- 
 flected light ; their laminse appear lemon-yellow by transmitted light, and if two such 
 thin plates be superposed in such a manner that their longest dimensions may cross 
 one another at right angles, the system is perfectly impervious to light, the two plates 
 acting in fact like two tourmalines with their axes crossed. (For further details re- 
 lating to these properties, see SULPHATE OF IODOQUININE, under QUININE). The salt 
 dissolves easily in strong boiling alcohol, and crystallises therefrom ; sparingly in 
 weak alcohol, and scarcely at all in water, ether, and chloroform. Herapath assigns 
 to it the formula C 30 H 38 N 4 O 2 I 6 .H 2 S0 4 + 3aq., which is very improbable, 
 
 Sulphate of Iodo-&-cinchonine is obtained in indistinct crystals on adding a warm 
 solution of 3 pts. iodine in 115 pts. alcohol to a solution of 10 pts. of sulphate of -cm- 
 chonine in 144 pts. acetic acid, and 12 pts. dilute sulphuric acid. (Schwabe.) 
 
 Derivatives of Cinchonine containing Organic Radicles. 
 
 BENZOYL-CINCHONINE, C 27 H 28 N 2 = C 20 H 28 (C 7 H 5 0)N 2 p. (Schiitzenberger, 
 Ann. Ch. Pharm. cviii. 351.) Dry cinchonine dissolves with rise of temperature in 
 chloride of benzoyl, and the mixture, if heated for a few seconds, solidifies to a crystalline 
 mass of hydrochlorate of benzoyl-cinchonine. This salt dissolves readily in water, and 
 the solution, quickly decanted from undissolved chloride of benzoyl, yields with ammonia 
 a white glutinous precipitate of benzoyl-cinchonine, which hardens in the cold. It is 
 tasteless and uncrystallisable, insoluble in water, but dissolves in all proportions in 
 
 3B 2 
 
980 CINCHOVATINE CINNAMEIN. 
 
 alcoliol and ether. Its salts are easily soluble in water. The hydrocUorate is 
 C 27 H 29 N 2 O.HC1 ; the chloroplatinate C^H^O 2 . 2(HCl.PtCl 2 ). 
 
 METHYL-CINCHONINE, C 21 H 26 N 2 0=C 20 H 23 (CH 3 )N 2 0. (Stahlschmidt, Ann. Ch. 
 Pharm. xc. 218.) The hydriodate of this base, C 2I H 26 N 8 O.HI, is produced by the 
 action of iodide of methyl on pulverised cinchonine. It dissolves easily in boiling 
 water, and separates in fine needles on cooling. It is not attacked by iodide of 
 methyl when heated therewith to 100 C. in a sealed tube : hence cinchonine appears to 
 contain but 1 at. of hydrogen replaceable by an alcohol-radicle. 
 
 The iodide treated with oxide of silver, yields a solution of the base, which, when 
 quickly evaporated over the water-bath, leaves a brown crystalline mass, from which, 
 when dissolved in water, brown oily drops separate. The aqueous solution precipitates 
 the salts of sesquioxides. 
 
 The salts of methyl-cinchonine are very soluble in water and in alcohol, and difficult 
 to crystallise. 
 
 The cUoroplatinate, C 21 H 26 N 2 0.2(HCl.PtCl 2 ), yields when dried at 100C., 2670 
 2677 per cent, platinum, the formula requiring 26-93. 
 
 CINCHOVATINE. Syn. with ARICTNEV (p. 357). 
 
 CINNABAR. Pro tosulphide of mercury. (See MEBCUBY.) 
 
 P9TI7O > 
 
 CIWlffAMEIW. Cinnamate of Benzyl C 16 H 14 2 = rO. (Plantamour, 
 
 Ann. Ch. Pharm. xxvii. 329 ; xxx. 241. Fr&my, Ann. Ch. Phys. Ixx. 189. H. De- 
 ville, Ann. Ch. Pharm. Ixxiv. 230. E. Kopp, Compt. chim. 1850, p. 410. 
 Scharling, Ann. Ch. Pharm. xcvii. 184. Grm. xiii. 283. G-erh. iii. 404.) This 
 compound was discovered by Plantamour (1838), who obtained it from balsam of 
 Peru, in which, according to Simon, it exists ready formed ; according to Fremy and 
 Deville, it exists also in small quantity in Tolu balsam. According to Scharling, 
 cinnamic acid dissolved in peruvin (a mixture of benzylic alcohol and toluene) forms a 
 liquid, which, when saturated with hydrochloric acid, yields to boiling water a neutral 
 oil resembling cinnamein. 
 
 Preparation. Balsam of Peru is saponified by agitation with excess of caustic 
 potash, and the solid soap dissolved in water : the solution on being warmed, separates 
 after a few minutes into two layers, and the upper, which is oily, is to be repeatedly 
 washed with water, till the oil exhibits a faint reddish-yellow colour. The residual 
 water is evaporated over the water-bath ; the oil dissolved in warm alcohol and evapo- 
 rated ; and this treatment repeated as long as resin separates out on evaporation. 
 (Plantamour). 2. Balsam of Peru dissolved in alcohol of 36, is treated with alco- 
 holic potash, whereby a compound of resin with potash is precipitated ; the solution is 
 mixed with water ; the cinnamein which separates out in the form of an oil is separated 
 from the inferior solution of cinnamate of potassium, and dissolved in freshly -rectified 
 rock-oil, whereby resin is removed ; the rock-oil is then evaporated, and the residual 
 oil placed in a vacuum. Cinnamein thus prepared, still retains styracin in solution, the 
 quantity varying according to the nature of the balsam. To free it from this im- 
 purity, it is dissolved in weak alcohol, and cooled for several days below 0, as long as 
 a crystalline deposit of styracin continues to form (Fremy). 3. Balsam of Peru is 
 repeatedly boiled with aqueous carbonate of sodium, and the cinnamate of sodium is 
 removed by washing, the residue then separating into a resin, and a yellowish-brown 
 liquid which must be heated to 170 C. on the oil- bath, and distilled in steam heated 
 to 170. Colourless, somewhat milky cinnamein then passes over, and is freed from 
 adhering water by standing for some time in a warm place, over chloride of calcium. 
 Sometimes, perhaps always, the cinnamein thus prepared contains in solution styracin, 
 which, after long standing, partially crystallises out (Scharling). Calcined mag- 
 nesia or oxide of lead also separates cinnamein from balsam of Peru, by combining with 
 the cinnamic acid, and separating resin. (Simon.) 
 
 Properties. Cinnamein is a feebly coloured or colourless, strongly refracting, neutral 
 oil, which remains liquid when cooled to 12 or 15 C. for several days. It boils 
 at 305, and distils without decomposition (Plantamour); between 340 and 350, 
 with partial decomposition (Deville, Fremy). It has a feeble pleasant odour. Its 
 taste is sharp and aromatic, recalling that of fat. It makes grease spots on paper. 
 Specific gravity, 1-098 at 14; 1-0925 at 25 (Scharling). It is nearly insoluble in 
 water, but dissolves in alcohol and ether. 
 
 Cinnamein contains, according to Scharling's analysis, 79*18 to 7 9 -24 per cent. C, 
 6-56 to 6-03 H, and 14-26 to 13720, agreeing nearly with the preceding formula, 
 which requires 80-62 C, 5'88 H, and 13-45 0. When kept under water for some time, 
 it yields a crystalline substance of the same composition, metacinnamein, which melts 
 between 12 and 15 C. sometimes resolidifies after cooling and standing, but after solu- 
 tion in boiling alcohol cannot again be obtained in the crystalline form. (Scharling.) 
 
CINNAMENE. 981 
 
 Cinnamein slowly absorbs moist oxygen (Fr6my). When exposed for years to air 
 and light, it acquires a rancid odour and acid reaction. Crystallised cinnamein preserved 
 in a glass vessel for a year melted to a viscous mass, and in another year solidified to a 
 transparent amorphous mass (Scharling). Cinnamein is partially decomposed by dis- 
 tillation, leaving a small quantity of tar, and yielding a distillate differing in compo- 
 sition from the original substance. 
 
 It is resinised by strong sulphuric acid (Fr6my. It slowly absorbs chlorine, more 
 easily when heated, becoming at the same time coloured and thickened, and when dis- 
 tilled, ultimately yields chloride of benzoyl together with an oil (Fremy). Nitric 
 acid acts briskly on cinnamein when heated, forming a yellow resin and a large 
 quantity of bitter almond oil. Peroxide of lead acts in a similar manner (Fremy). 
 Cinnamein forms a crystalline compound with ammonia (Plantamour). Mixed with 
 sulphide of carbon and powdered hydrate of potassium, it forms a saline mass con- 
 taining xanthate of potassium (Scharling). Rapidly heated with very concentrated 
 potash-ley, or melted with hydrate of potash, it gives off hydrogen, and passes into 
 cinnamate (and benzoate) of potassium (Fremy). Treated with very concentrated 
 potash-ley in the cold, or with alcoholic potash, it is completely resolved, in 24 hours, 
 without disengagement of gas or absorption of oxygen, into benzylic alcohol and cin- 
 namate of potassium : C 16 H M 2 t- KHO = C 7 H 8 + C 9 H 7 E:0 2 . By the continued 
 action of the potash, the benzylic alcohol may be converted into benzylene. (C 7 H 8 .) 
 
 Plantamour, by treating cinnamein with strong alcoholic potash, obtained, together 
 with cinnamic acid, an acid which he designated as carbobenzoic or myroxylic acid ; 
 probably impure benzoic-acid resulting from the decomposition of cinnamic acid under 
 the influence of potash (p. 984). 
 
 CIN-NAMENE. C 8 H 8 . Cinnamol. Styrol. Volatile Oil of Liquid Storax. (Bo- 
 nastre, J. Pharm. xvii. 338. D'Arcet, Ann. Ch. Phys. Ixvi. 110. Mulder, J. pr. 
 Chem. xv. 307. E. Simon, Ann. Ch. Pharm. xxxi. 265. C. Herzog, Pharm. Centr. 
 1839, p. 833. Gerhardt and Cahours, Ann. Ch. Phys. [3] i. 96. E. Kopp, Compt. 
 chim. 1846, p. 87; further, Compt. rend. liii. 634. Blyth and Hofmann, Ann. Ch. 
 Pharm. liii. 293, 325. Hempels, ibid. lix. 316. Scharling, ibid, xcvii. 184. 
 D. Howard, Chem. Soc. Qu. J. xiii. 134; Gm.xiii.l; Gerh.iii. 374.) This compound 
 is produced by the decomposition of cinnamic acid (p. 981), and is contained in liquid 
 Btorax (p. 982), whence it may be obtained by distillation with water. It was for- 
 merly supposed that cinnamene obtained from cinnamic acid was not identical, but 
 only isomeric, with styrol, the volatile oil of storax, because the latter is completely 
 converted by heat into a solid substance, mctastyrol, of the same composition, whereas 
 with cinnamene this change had been observed to take place but imperfectly ; but E. 
 Kopp has lately shown that this transformation takes place quite as completely with 
 cinnamene as with styrol, an observation which removes the only objection to the sup- 
 posed identity of the two substances. 
 
 Preparation. a. From Cinnamic Acid and the Cinnamates. Cinnamic acid, when 
 slowly distilled at its boiling point, is completely resolved into cinnamene and carbonic 
 anhydride : 
 
 C 9 H 8 2 = CO 2 + C 8 H 8 . 
 
 Pure cinnamate of calcium is likewise resolved by dry distillation into cinnamene and 
 carbonate of calcium (D. Howard). Cinnamic acid distilled with excess of lime or 
 baryta yields a mixture of cinnamene and benzene, which may be separated by rec- 
 tification. 
 
 b. From Storax. The liquid balsam is distilled in a copper still connected with a 
 worm-tub, with water containing carbonate of sodium, to retain cinnamic acid ; 3| Ibs. 
 of carbonate of sodium suifice for 10 Ibs. of storax. The water which passes over is 
 milky, and the cinnamene floats on the surface. The quantity obtained varies with the 
 age of the balsam. Blyth and Hofmann obtained in one operation about 360 grammes 
 of oil from 20| kil. of liquid storax, in another not more than 90 grms. from 13| kil. 
 The oily distillate is dried over chloride of calcium and rectified. This last operation 
 requires particular precautions. The liquid begins to give off vapour between 100 and 
 120 C., and at 145 it is in full ebullition, a limpid oil then passing over, and the 
 thermometer remaining stationary for some time ; suddenly, however, a considerable 
 rise takes place, and the thermometer must then be quickly withdrawn from the retort, 
 for the residue thickens, and on cooling solidifies to a transparent glass, consisting of 
 metacinnamene or metastyrol. The quantity of this solid residue varies, but it some- 
 times amounts to half the oil subjected to distillation. 
 
 c. Cinnamene may also be obtained from the resin of Peru balsam, by heating that 
 substance mixed with pumice to dull redness in a retort, and subjecting the oil which 
 passes over, together with benzoic acid and an aqueous liquid, to fractional distillation. 
 The portion which goes over under 175 C., and is lighter than water, is collected, re- 
 peatedly distilled with potash-solution, allowed to stand several days over piecesiof solid 
 
982 CINNAMENE. 
 
 potash, and then distilled at a temperature not exceeding 150 C. The distillate is dried 
 with chloride of calcium, treated with potassium, whereby hydrogen is evolved, and the 
 fluid part is decanted from the resulting gelatinous precipitate and distilled. The boiling 
 point then gradually rises to 100 140 C., by which time all the cinnamene remains 
 behind, amounting to f of the liquid employed. (Scharling, Ann. Ch. Pharm. xcvii. 
 184.) 
 
 Cinnamene is a very mobile colourless oil, having a strong persistent aromatic odour, 
 reminding of benzene and naphthalene together. It does not solidify at 20 C. It 
 is very volatile, the grease spots which it produces on paper disappearing in a few 
 seconds. Specific gravity 0'924. Boiling point 14575 C. (Blyth and Hoffmann) ; 
 145 (E. Kopp). It is neutral, mixes in all proportions with alcohol and ether, vola- 
 tile oils, and sulphide of carbon, and dissolves sulphur and phosphorus. 
 
 Cinnamene is not acted upon by potash. With fuming sulphuric acid it appears to 
 form a conjugated acid. If added by drops to fuming nitric acid, it dissolves with 
 evolution of red vapours ; and water added to the solution throws down a yellow resin, 
 which, by careful distillation, yields crystals of nitrocinnamene. If boiled with 
 excess of nitric acid, it yields benzoic or nitrobenzoic acid, according to the strength 
 of the nitric acid. Distilled with dilute chromic acid, it yields crystals of nitrobenzoic 
 acid. With chlorine and bromine, it forms chloride and bromide of cinnamene. 
 
 METACINNAMENE. Metastyrol. DraconyL This is the solid substance into which 
 cinnamene or styrol is converted by the action of heat. The conversion takes place 
 readily in a sealed tube heated to 200 C. in an oil-bath. Metacinnamene is likewise 
 obtained from dragon's blood. When the crude oil produced by the dry distillation of 
 that substance is distilled till the temperature rises to 280 C. a liquid is obtained con- 
 taining toluene (hydride of benzyl, p. 573), and cinnamene. On distilling this mixture 
 at a temperature below the boiling point, till the greater part of the toluene has passed 
 over, a viscous liquid remains, consisting of metacinnamene, held in solution by a 
 small quantity of styrol. On pouring this liquid into alcohol, the cinnamene dissolves, 
 while the metacinnamene is precipitated in the form of a soft colourless resin like tur- 
 pentine, which may be washed with alcohol, and then dried in a stove at 150 C. 
 
 According to E. Kopp, the transformation of cinnamene into metacinnamene likewise 
 takes place spontaneously at ordinary temperatures. This property, joined to the high 
 refracting power of metacinnamene, suggests the possibility of using cinnamene for 
 filling hollow glass lenses or prisms. According to Kovalevsky (Ann. Ch. Pharm. 
 cxx. 66), metacinnamene exists also, together with cinnamene, in liquid storax. 
 
 Metacinnamene is a colourless, limpid, highly refractive substance, destitute of taste 
 and odour. At mean temperatures it is hard, and may be cut with a knife ; but it softens 
 by heat, and may then be drawn out into long threads. It is insoluble in water and 
 alcohol ; ether dissolves it in small quantity, and at the boiling heat transforms it into 
 a gelatinous mass, which, after drying at 100 C., forms a white spongy substance, 
 having exactly the composition of styrol. 
 
 Metacinnamene liquefies when heated in a small retort, and yields by distillation 
 pure cinnamene, which may be reconverted into metacinnamene by heating to 200 C. 
 in a sealed tube. 
 
 Chlorine and bromine act very slowly on metacinnamene, but ultimately convert it 
 into chloride and bromide of cinnamene respectively. Strong sulphuric acid carbo- 
 nises it. By fusion with hydrate of potassium it is converted into styrol. Nitric acid of 
 ordinary strength acts but slightly on metacinnamene, but fuming nitric acid dissolves 
 it easily, with evolution of red vapours ; and if the acid has been added in sufficient 
 quantity, the solution yields with water a precipitate ofnitrometacinnamene. 
 
 Compounds and Derivatives of Cinnamene. 
 
 BROMIDE OF CHINAMENE. C 8 H 8 Br 2 . Produced by the action of bromine on cinna- 
 mene. It is insoluble in water, but very soluble in alcohol and ether, whence it crys- 
 tallises in needles. Solutions saturated at the boiling heat usually deposit it in the 
 form of an oil, which remains liquid for a long time, and solidifies suddenly when 
 agitated. It has a peculiar odour, which is not disagreeable, but excites tears. It 
 melts at 67 C., and often remains liquid, even when cooled to 30 C., but the least 
 agitation causes it to solidify in a crystalline mass. Its boiling point is above 200 C. 
 It may be distilled almost wholly without alteration. Alcoholic potash converts it 
 into bromide of potassium and a brominated organic compound. 
 
 Chloride of Cinnamene. C 8 H 8 CP. Oily liquid, produced by the action of chlorine 
 on cinnamene. It is decomposed by distillation into hydrocliloric acid and another 
 oily compound. 
 
 Treated with alcoholic potash, it yields chlorocinnamene, C 8 H 7 Cl. 
 
 Trichloride of Dichlorocinnamene, C 8 H 6 C1 2 .3C1 8 , is obtained, according to Laurent, 
 by the action of clilorine on cinnamene. 
 
CINNAMIC ACID. 983 
 
 NITROCINNAMENE. Nitrostyrol C S H 7 (N0 2 ). Produced by the action of fuming 
 nitric acid on cinnamene (p. 980). It crystallises in large prisms ; has an odour of 
 cinnamon which excites tears ; produces painful blisters on the skin. 
 
 Nitrometacinnamene. Nitrometastyrol. Nitrodraconyl. This compound, isomeric 
 with the last, is precipitated on adding water to the product of the action of fuming 
 nitric acid on metacinnamene. It is a white amorphous powder, insoluble in water, 
 acids, potash, ether, and alcohol. When slightly heated, it burns with explosion. 
 When distilled with lime, it is decomposed, with separation of carbon and evolution of 
 ammonia, together with a small quantity of a brown oil containing phenylamine. It 
 does not appear to be attacked by strong nitric acid, even after several hours' boiling. 
 
 CIN3XTA1VIIC ACID. C 9 H 8 2 = ^^.CO. Zimmtsdure. Cinnamylsdure. 
 
 (Dumas and Peligot [1834], Ann. Ch. Phys. Ivii. 311. E. Simon, Ann. Ch. Pharm. 
 xxxi. 265. Stenhouse, ibid. Iv. 1; Ivii. 79. Herzog, Arch. Pharm. xvii. 72; 
 xx. 159. E. Kopp, Compt. chim. 1847, p. 198; 1849, p. 146; 1850, p. 140. Ca- 
 hours, Ann. Ch. Phys. [3] xxiii. 341. Schabus, Wien Akad. Ber. 1850 [2] 206. 
 Chiozza, Ann. Ch. Phys. [3] xxxix. 439. J. Lowe, J. pr. Chem. Ixv. 188. Piria, 
 Ann. Ch. Pharm. c. 104. Bertagnini, Cimento, iv. 46. Gm. xiii. 268. G-erh. 
 iii. 388.) This acid exists in the free state in several balsams, as in liquid sfcorax, 
 Tolu balsam, Peru balsam, and gum benzoin, and is often deposited in large prismatic 
 crystals from old samples of oil of cinnamon ; also from cinnamon -water. 
 
 Formation. Cinnamic acid is produced : 1. By the action of oxidising agents on cin- 
 namic aldehyde and on styrone. 2. By heating bitter-almond oil with chloride of 
 acetyl in a sealed tube to 120 130 C., but not higher, for 20 24 hours, hydrochloric 
 acid being formed at the same time : 
 
 C 7 H G + C 2 H 3 O.C1 = HC1 + C 9 H 8 2 . 
 
 The cinnamic acid may be extracted from the viscid residue by digestion with water 
 containing ammonia. 3. By boiling cinnamein with potash, benzylic alcohol being 
 formed at the same time (p. 979). 4. By fusing styracin with potash (Fr6my) or 
 boiling it with potash-ley. (Simon.) 
 
 Preparation. a. Prom the deposit of cinnamate of lead mixed with cinnamic acid, 
 found in the old leaden packages in which oil of cassia-cinnamon is imported. The 
 deposit is dissolved in alcohol and filtered from the cinnamate of lead, and the alcohol 
 is removed from the filtrate by distillation ; the cinnamic acid then quickly crystallises 
 out from the oil, and is purified by treatment with carbonate of sodium and precipitation. 
 The residual cinnamate of lead is boiled with carbonate of sodium, filtered from the 
 carbonate of lead, and the cinnamic acid is precipitated by dilute sulphuric acid, in 
 silvery lustrous laminae, which are washed, and recrystallised from alcohol (Herzog). 
 Dumas and Peligot dissolve the crystalline deposit from oil of cinnamon in boiling 
 water, and evaporate the filtrate to the crystallising point. 
 
 b. From Liquid Storax. Liquid storax is distilled with water and ^ to ^ pts. of crys- 
 tallised carbonate of sodium, whereupon styrol passes over. The residual aqueous liquid 
 is filtered from the resin ; and the filtrate is mixed at first with just so much sulphuric 
 acid, that a very small quantity of cinnamic acid is precipitated along with dissolved 
 resin ; and the liquid filtered from this precipitate is treated with excess of sulphuric 
 acid, which precipitates cinnamic acid of a tolerably white colour. It is dissolved 
 in a large quantity of water, with as little carbonate of sodium as possible, and again 
 precipitated, first with a little sulphuric acid, and then, after the filtration, with an 
 excess of acid, by which a white precipitate is formed. This is washed with water, 
 dried, and dissolved in alcohol, which, by spontaneous evaporation, yields quite white 
 and very large crystals (E. Simon). Erdmann and Marchand purify the acid by dis- 
 tillation, pressure between paper moistened with alcohol, and repeated crystallisation. 
 D. Howard (Chem. Soc. Qu. J. xiii. 72) finds that cinnamic acid prepared from liquid 
 istorax contains a small quantity of benzoic acid, from which, however, it is purified by 
 crystallisation from alcohol. 
 
 c. From Balsam of Peru. When the slimy residue which deposits in Peruvian 
 balsam by keeping, is dissolved in warm alcohol, and the filtrate is placed in a tall 
 and narrow cylinder with a layer of water on the top, crystals of nearly pure cinnamic 
 acid separate in a few days from the clear brown liquid (Herberger). When Peru- 
 vian balsam is boiled with thick milk of lime, the liquid filtered, the residual magma 
 exhausted three or four times with boiling water, and the solution again filtered, the 
 filtrate deposits on cooling, loose, almost white masses of crystals; and these, when 
 decomposed by hydrochloric acid, yield nearly pure cinnamic acid, which may be ob- 
 tained perfectly pure, either by distillation, or by solution in ammonia, filtration, and 
 precipitation while hot by hydrochloric acid (E. Kopp). Simon proceeds as with 
 storax. 
 
 3 B 4 
 
984 CINNAMIC ACID. 
 
 d. From Balsam of Tolu. Balsam of Tolu is boiled six or seven times with solu- 
 tions of carbonate of sodium, which are taken continually weaker (the last extracts only 
 contain a little benzoic acid, produced by the action of the alkali on the resin) ; and 
 the alkaline decoctions are strongly concentrated by evaporation, and precipitated hot 
 by hydrochloric acid, whereupon most of the einnamic acid melts into a brown resin, 
 and but little crystallises out on cooling. The latter is pressed, the resin is pulverised, 
 and both are dissolved in ammonia diluted with 2 pta. of water, and heated to 80 C. 
 The greater part of the resin then remains dissolved. The liquid is filtered; the. re- 
 sidue is boiled with water ; and the whole of the very brown liquids are evaporated 
 and decomposed, while boiling, by hydrochloric acid, whereupon most of the acid again 
 melts, while the remainder seprates out on cooling in nearly white crystalline scales, 
 which are pressed, and washed with a little cold water. The melted acid is also washed 
 with a little water. The whole of the acid is heated in a porcelain dish covered with 
 paper till the water is expelled very little acid subliming even at 200 C. and the 
 fused residue is bruised and distilled. Pure einnamic acid then passes over as a colour- 
 less, clear, strongly refracting liquid, which solidifies to a white crystalline mass like 
 stearin. Towards the end, yellowish vapours arise, which, when collected in another 
 receiver, solidify into a mass of acid, which is contaminated by the presence of the em- 
 pyreumatic oils of the resin, but may be obtained quite pure by recrystallisation from 
 boiling water. (E. Kopp.) 
 
 Properties. Cinnamic acid crystallises in colourless prisms or laminae belonging to 
 the monoclinic system. Ordinary combination, ooP . [ coPoo ] . [Poo ]. Ratio of ortho- 
 diagonal, clinodiagonal, and principal axis = 0'3674 : 1 : 1-1694. Inclination of clino- 
 diagonal to principal axis = 82 58'. Cleavage perfect parallel to [ ooPco ]. Specific 
 gravity of crystals = 1-195. 
 
 Cinnamic acid dissolves sparingly in cold water, easily in boiling water, alcohol, and 
 ether; water precipitates it from the alcoholic solution. It melts at 129 C., and boils 
 without decomposition at 293 (Dumas andPeligot), at 300 304 (E.Kopp), with 
 or without decomposition, according to the manner in which it is heated. If enclosed 
 in a sealed tube, it may be heated to 200 C. (in a paraffin-bath) for several hours 
 without alteration. (Howard.) 
 
 Decompositions. 1. Cinnamic acid, when slowly distilled, is resolved into cinnamene 
 and carbonic anhydride: C 9 H 8 2 = C 8 H 8 + CO 8 , a small quantity of stilbene, C"H 12 , 
 being likewise produced, and passing over with the cinnamene (Howard). 2. On red- 
 hot platinum-foil, or in the flame of a candle, it burns with a smoky flame (Biz io). On 
 red-hot charcoal, it evaporates without flame producing a strong biting smoke. 3. Strong 
 sulphuric acid, or sulphuric anhydride, converts it into sulpho-cinnamic acid. 4. Cin- 
 namic acid heated with excess of iodine, melts to a dark brown mass ; and when this 
 mass is heated with water, and the excess of iodine expelled by evaporation, iodocin- 
 iiamic acid crystallises out on cooling (Herzog). 5. Bromine passed over cinnama'e 
 of silver forms bromocinnamic acid (Herzog). 6. Chlorine passed in diffused daylight 
 over dry einnamic acid, forms a tough greasy substance, which, when heated with 
 carbonate of potassium, forms chlorocinnamate of potassium, and deposits a white oil 
 containing chlorine (Herzog). The same products are formed when chlorine is passed 
 into warm aqueous einnamic acid or cinnamate of sodium, and when einnamic acid is 
 distilled with hypochlorite of calcium (Stenhouse, E. Kopp), or with chlorate of 
 potassium and hydrochloric acid. 7. Strong nitric acid converts einnamic acid into 
 nitrobenzoic acid, provided the mixture be kept cool ; otherwise nitrous fumes are 
 evolved, and hydride of benzoyl is first obtained, then benzoic and nitrobenzoic acids. 
 The same products are formed on heating einnamic acid with more dilute nitric acid. 
 8. Boiled with peroxide of lead in aqueous solution, einnamic acid gives off the odour 
 of bitter- almond oil, while the peroxide of lead assumes a light yellow colour, and is 
 partially converted into benzoate of lead. This behaviour serves to distinguish ein- 
 namic acid from benzoic acid (Stenhouse). 9. Cinnamic acid distilled with sulphuric 
 acid and acid chromate of potassium, yields oil of bitter-almonds (Simon). 10. With 
 pentachloride of phosphorus (also the trichloride, according to B 6 champ), it yields 
 chloride of cinnamyl (Cahours). 11. Fused with hydrate of potassium, it gives off 
 hydrogen, and forms acetate and benzoate of potassium, a small quantity of salicylate 
 of potassium being also produced by the action of potash on the benzoic acid pre- 
 viously formed (C hi o z z a) : 
 
 C 9 H 8 2 + 2KHO = C 2 H 3 K0 2 + C 7 H 5 K0 2 + H 2 . 
 
 Cinnamic acid is not decomposed by boiling with strong caustic potash (Simon). 
 
 12. In the dry distillation of the alkaline cinnamates or of einnamic acid with caustic 
 baryta or lime, a carbonate is formed, together with cinnamene and benzene. 
 
 13. Cinnamate of calcium, distilled with formate of calcium, yields einnamic aldehyde 
 (Piria.) The reactions 6, 7, and 8, serve to distinguish cmnamic acid from benzoic 
 acid. 
 
CINNAMIC ACID. 985 
 
 CINNAMATES. Cinnamic acid is monobasic, the formula of its salts being C'H^O 2 . 
 They are crystallisable, and bear considerable resemblance to the benzoates. The 
 cinnamates of the alkali-metals are easily soluble in water ; those of the earth-metals 
 and heavy metals sparingly soluble, the least soluble being the silver-salt. They dis- 
 solve more readily in water containing chlorides or nitrates. 
 
 The solutions of most cinnamates yield a precipitate of cinnamic acid when decom- 
 posed by the stronger acids. Cinnamates are decomposed by dry distillation, giving 
 off an odour of bitter- almonds. With strong nitric acid, they turn yellow, and give off 
 the odour of oil of cinnamon and bitter-almond oil. They likewise yield bitter-almond 
 oil when distilled with chromic acid. With ferric salts, they give a yellow precipitate, 
 and with manganous salts, the cinnamate being in excess, a white precipitate which 
 soon becomes yellowish and crystalline. Benzoates give a reddish precipitate with 
 ferric salts, and none with manganous salts. The cinnamates have been investigated 
 chiefly by Herzog (J. pr. Chem. xxix. 51), and E. Kopp (Compt. rend. liii. 634). 
 
 Cinnamate of Aluminium. Loose white powder, sparingly soluble in cold, easily in 
 hot water. 
 
 Cinnamate of Ammonium, 2C 9 H 7 (NH 4 )0 2 4 aq. Sparingly soluble in cold water : 
 gives off ammonia when melted, yielding a crystalline sublimate and a resinous residue. 
 With excess of cinnamic acid, it forms an acid salt still less soluble in water. (Herzog.) 
 
 Cinnamate of Antimony and Potassium is deposited from a mixture of cinnamate 
 of potassium and tartar-emetic, in delicate hydrated crystals, which redissolve if left 
 for a long time in the liquid. The salt yields by calcination, a colourless residue, 
 which effervesces with acids, and is coloured orange-red by sulphuretted hydrogen. 
 (Herzog.) 
 
 Cinnamate of Barium, 2C 9 H 7 Ba0 2 4- aq. Precipitate, soluble in boiling water, crys- 
 tallising on cooling. Gives off its water at 110 C. (Herzog). According to E. Kopp, 
 the salt forms broad, irregular, transparent, nacreous laminse containing C 9 H 7 Ba0 2 + aq. 
 becomes anhydrous at 140 C. and when distilled with excess of bary tic hydrate, yields 
 nearly pure cinnamene. 
 
 Cinnamate of Calcium, C 9 H 7 Ba0 2 + aq. Very little soluble in cold water, easily in 
 boiling water, whence it separates in light crystalline masses (Herzog). 2C 9 H 7 Ca0 2 + 
 3 aq. White shining needles composed of thin nacreous laminae, having the form of 
 nearly rectangular parallelograms. It gives off one-third of its water when exposed to 
 the air at ordinary temperatures, and the rest at 150 C. (E. Kopp.) 
 
 Cinnamate of Cobalt. Rose-coloured precipitate, soluble in alcohol. (Herzog.) 
 
 Cinnamate of Copper, C 9 H 7 Cu0 2 ..rCuHO. The greenish-blue precipitate obtained 
 by double decomposition, is a highly hydrated basic salt. When heated, it loses its 
 blue colour and decomposes, giving off cinammic acid and cinnamene, and leaving 
 metallic copper mixed with charcoal. 
 
 Cinnamates of Iron. Both the ferric and ferrous salts are yellow precipitates, spar- 
 ingly soluble in water. (Herzog.) 
 
 Cinnamate of Lead, C 8 H 7 Pb0 2 . Granular crystalline powder, anhydrous and in- 
 soluble in water (Herzog). Sometimes obtained in laminse, flattened or elongated 
 into needles, and in small hard rounded grains (E. Kopp). Alcohol extracts a portion 
 of the cinammic acid, leaving a basic salt. 
 
 Cinnamate of Magnesium, 2C 9 H 7 Mg0 2 + 3aq., crystallised in the cold, forms small 
 white needles, which quickly become opaque on being exposed to the air. From a 
 boiling solution it separates in tufts of shining needles, formed by the superposition of 
 elongated laminae, very thin, and of nacreous aspect. It melts at 200 C. and be- 
 comes anhydrous. 
 
 Manganous Cinnamate, C 9 H 7 Mn0 2 + aq. Yellowish- white crystalline precipitate, 
 which dissolves in boiling water acidulated with acetic acid, and separates therefrom in 
 shining yellowish laminse, superposed on one another. (E. Kopp.) 
 
 Mercurous Cinnomatc. White curdy precipitate. 
 
 Cinnamate of Nickel. Green precipitate soluble in alcohol. 
 
 Cinnamate of Potassium, 2C 9 H 7 K0 2 +aq. Crystals belonging to the monoclinic 
 system, giving off their water at 120C, and decrepitating when strongly and suddenly 
 heated. It is very soluble in water, but less so than the benzoate ; moderately soluble 
 in alcohol (Herzog). From a rather strong boiling solution containing excess of caustic 
 potash, it crystallises readily in nacreous needles, which are anhydrous. (E. Kopp.) 
 
 When cinnamic acid is dissolved in a hot solution of cinnamate of potassium, a 
 sparingly soluble acid salt is deposited on cooling. (Herzog.) 
 
 Cinnamate of Silver, C'H'AgO 2 . White curdy precipitate, becoming crystalline 
 after a while ; not much altered by light. It is insoluble in boiling water, but dis- 
 solves slightly in the liquid from which it has been precipitated (Herzog). White 
 .precipitate, or silky nacreous needles composed of small elongated laminse, often bi- 
 furcated. (E. Kopp.) 
 
986 CINNAMJC ACID. 
 
 solution in weak caustic soda, it crystallises in beautiful needles containing i at. water 
 of crystallisation. In strong caustic soda, it dissolves but sparingly at common tempe- 
 ratures, separating in hard, yellowish, radiated, anhydrous spheres. (E. Kopp.) 
 
 Cinnamate of Strontium, C 9 H 7 Sr0 2 + 2aq., when recently crystallised, forms white, 
 nacreous, nearly opaque needles, composed of very small prisms. It is much more 
 soluble in hot than in cold water ; gives off 1 at. water when exposed to dry air, and 
 the rest at 140 C. (E. Kopp.) 
 
 Cinnamate of Tin. The stannic s&lt is a white precipitate. (Herzog.) 
 Cinnamate of Uranyl. Yellow precipitate, sparingly soluble in boiling water. 
 (Herzog.) 
 
 Cinnamate of Zinc. Cinnamic acid dissolves zinc at the boiling heat, with evolution 
 of hydrogen. 'The salt is moderately soluble, and crystallises by evaporation (H e r- 
 zog), C 9 H 7 Zn0 2 + aq. White precipitate, which dissolves in boiling water, and 
 crystallises therefrom in shining, transparent, prismatic needles, sometimes grouped 
 like mushrooms. (E. Kopp.) 
 
 CINNAMIC ETHEBS. Cinnamate of Ethyl, C H H 12 2 = C 9 H 7 (C 2 H 5 )0 2 . (Her- 
 zog, Arch. Pharm. [2] xvii. 72. Marchand, Ann. Ch. Pharm. xxxii. 270. E. Kopp. 
 J.pr. Pharm. [3] xi. 72. Plantamour, Ann. Ch. Pharm. xxx. 345). This compound 
 is easily obtained by distilling a mixture of 4 pts. absolute alcohol, 2 pts. cinnamic 
 acid, and 1 pt. sulphuric acid, cohobating the product several times, agitating with water 
 the oil which remains in the retort, and rectifying over massicot. It is a limpid 
 liquid, of specific gravity 1'3, boiling at 262 C. (Herzog); at 266, when the cor- 
 rection is made for the column of mercury projecting above the retort (H. Kopp). 
 Vapour-density 6*537 at 291 C. (by calculation for 2 vol. = 6-101). 
 
 Cinnamate of ethyl is nearly insoluble in water, but dissolves readily in alcohol and 
 in ether. It is scarcely attacked by fuming nitric acid. Alkaline hydrates easily con- 
 fert it into alcohol and a cinnamate of the alkali-metal. 
 
 Cinnamate of Methyl, C 10 H IC 2 = C y H 7 (CH 3 )0 2 (E. Kopp, Compt. rend. xxi. 
 1376). Obtained by saturating a mixture of cinnamic acid and wood-spirit with hy- 
 drochloric acid gas at a gentle heat, precipitating the product with water, then drying 
 and rectifying. It is a colourless, oily liquid, having an agreeable aromatic odour. 
 Specific gravity 1-106. Boiling point 241 C. 
 Cinnamate of Benzyl, or Cinnamein (p. 982). 
 
 Cinnamate of Cinnyl, C I8 H I6 2 = C 9 H 7 0(C 9 H 9 )0. Cinnamyl-styrone, Styracin. 
 (Bonastre, J. Pharm. June, 1831, p. 338. E. Simon, Ann. Ch. Pharm. xxxi. 365. 
 E. Kopp, Compt. chim. 1850, p. 140. Toel, Ann. Ch. Pharm. Ixx. 1. Strecker, 
 ibid. Ixx, 40; Ixxiv. 112. Plantamour, ibid, xxvii. 239; xxx. 341 Gossmann, 
 ibid. xcix. 376. Scharling, ibid, xcvii. 90, 174. Gm. xiii. 286. Gerh. iii. 403.) 
 This compound, which bears to cinnylic alcohol or styrone (p. 992) the same relation 
 that acetate of ethyl bears to common alcohol, is contained in liquid storax (p. 497), 
 together with cinnamic acid, styrol, and several resins ; also in balsam of Peru. 
 
 Preparation from Storax. 1. The balsam is distilled with water to expel the styrol, 
 and then boiled with aqueous carbonate of sodium, which extracts the free cinnamic acid. 
 The residue thus obtained is a resinous spongy mass, which contains oily styracin in its 
 pores, and when kneaded with the fingers becomes more and more compact, while the 
 oily styracin runs out. 2. Toel dries the resinous cake which remains after boiling the 
 liquid storax with carbonate of sodium, after it has been freed from the solution of 
 cinnamate of sodium ; macerates it repeatedly with cold alcohol, which extracts the co- 
 louring resin, and leaves most of the styracin but little coloured ; and obtains the 
 styracin quite pure by repeated crystallisation from ether-alcohol. 3. Wolff allows the 
 resinous cake to stand for some time in cold alcohol, when it soon becomes crystalline ; 
 frees the crystals from resin by dissolving them in boiling alcohol, and precipitating 
 the resin with acetate of lead ; and frequently recrystullises, first from ether-alcohol, 
 then from ether. 4. After distilling liquid storax with water, and repeatedly boiling 
 the residue with carbonate of sodium, the undissolved portion is slowly allowed to 
 cool to 30 40 : the mass then becomes tough and spongy, and a yellow oil collects 
 in its pores. This oil made to run out by kneading and pressing, and then filtered, 
 solidifies after some time into a crystalline mass, which is purified by recrystallisation 
 from alcohol. The residual mass still contains much styracin, and is therefore worked 
 up for styrone (E. Kopp). 5. The residue left after distilling liquid storax with 
 water, separates when repeatedly boiled with carbonate of sodium, into a solid, dark 
 resin, and liquid styracin. The latter is poured off, transferred to a flask, which is 
 
 E laced in an oil-bath at the temperature of 180 0., and distilled by passing steam 
 eated to 180 through it; it then passes over as a white milky oil, which, when freed 
 
CINNAMIC ACID. 987 
 
 from water, solidifies on standing in open vessels, to a faintly coloured crystalline mass, 
 which maybe recrystallised from alcohol (S char ling). 8. Liquid storax is mace- 
 rated or digested at a temperature not exceeding 30 C. with 5 to 6 pts. of dilute soda- 
 ley, till the residue becomes colourless ; this residue is collected, washed, dried and 
 dissolved in alcohol containing ether ; and from the solution, which, if not colourless, 
 is to be rendered so by treatment with animal charcoal, pure styracin crystallises out. 
 (Grossmann.) 
 
 Properties. Cinnamate of cinnyl,or styracin, crystallises in tufts of beautiful prisms, 
 destitute of taste and odour, insoluble in water, sparingly soluble in cold alcohol, very 
 soluble in ether. It melts at 44 C. (Toel, Scharling), at 38 (E. Kopp), and re- 
 mains liquid and viscous for a long time after cooling. It distils without decomposi- 
 tion in steam heated to 180 C. (Scharling.) 
 
 In treating storax as above described, styracin is sometimes obtained in a liquid, 
 uncrystallisable state, especially if it has been left too long in contact with acids to 
 free it from the last traces of soda. 
 
 Decompositions. Styracin in contact with caustic alkalis solidifies to a mass of 
 agglomerated granules. When distilled with potash, especially with strong alcoholic 
 potash, it is decomposed like other compound ethers, yielding cinnylic alcohol (styrone) 
 and cinnanaate of potassium : 
 
 C 9 H 7 
 
 Cinnamate Cinnylic Cinnamic 
 
 of cinnyl. alcohol, acid. 
 
 Heated with nitric acid it yields hydride of benzoyl, hydrocyanic acid, benzoic acid, 
 and nitrobenzoic acid. "With chromic acid, it yields hydride of benzoyl, benzoic acid, 
 and a resin. "With a mixture of sulphuric acid and peroxide of manganese, it yields 
 hydride of benzoyl. With strong sulphuric acid, it yields cinnamic acid and a brown 
 substance, soluble in water, insoluble in saline solutions. 
 
 Substitution-derivatives of Cinnamic Acid. 
 
 BROMOCINNAMIC ACID. C 9 H 7 Br0 2 . This acid is obtained by passing bromine 
 vapour in excess over cinnamate of silver, treating the decomposed salt with ether, 
 and evaporating the filtered solution. A thick oil then remains, which dissolves par- 
 tially in potash, and the alkaline solution decomposed by hydrochloric acid deposits 
 crystals of bromocinnamic acid. The portion of the oil insoluble in potash is probably 
 a bromide of carbon. 
 
 Bromocinnamic acid decomposes partially when dissolved in water and evaporated. 
 It forms easily soluble salts with all bases, and does not precipitate nitrate of silver. 
 (Herzog.) 
 
 CHLOROCINNAMIC ACID. C 9 H'C10 2 . (E. Kopp, J. Pharm. [3] xvi. 426. Toel, 
 Ann. Ch. Pharm. Ixx. 7.) Obtained: 1. By passing chlorine into a cold solution of 
 cinnamic acid in concentrated carbonate of sodium (Kopp). 2. By the action of alco- 
 holic potash on an alcoholic solution of chlorostyracin, a chlorinated oil and chloride of 
 potassium being formed at the same time. The mixture soon solidifies to a pulp, 
 which is washed with alcohol, pressed, dissolved in a small quantity of boiling alcohol, 
 and mixed with excess of hydrochloric acid. Chlorocinnamic acid then crystallises 
 out on cooling, and may be purified by recrystallisation. 
 
 The acid crystallises in long shining odourless needles, melting at 132 C., and sub- 
 liming at a higher temperature. Its vapour excites coughing. It is sparingly soluble 
 in cold water, melts in boiling water, dissolves easily in alcohol and ether. 
 
 Chlorocinnamate of Ammonium, 2C 9 H 6 C1(NH 4 )0 2 + aq., forms curved arbores- 
 cent needles. The potassium-salt forms lustrous pearly flakes. The barium-salt, 
 2C 9 IpClBa0 2 + a q ? j g precipitated as a white powder, soluble in boiling water, and 
 crystallising therefrom in shining laminae. The calcium-salt is sparingly soluble, and 
 resembles the barium-salt. The silver-salt, C 9 H 6 ClAg0 2 , is obtained by precipitation 
 from hot solutions, in slender needles which blacken on exposure to light. 
 
 Chlorocinnamate of Cinnyl or Chlorostyracin. C 18 H 12 C1 4 2 . Chlorine converts sty- 
 racin into a viscid substance, having an acrid taste and an odour like that of copaiba 
 balsam. It is insoluble in water, soluble in boiling alcohol and ether, whence it sepa- 
 rates in the amorphous state. It is decomposed by potash, yielding a chlorinated oil, 
 Chlorocinnamate of potassium, and chloride of potassium. Distilled in a current of 
 chlorine, it forms a volatile chlorinated liquid and a crystallisable chlorinated acid, the 
 salts of which also crystallise readily. (E. Kopp.) 
 
 NITROCINNAMIC ACID. C 9 H 7 (N0 2 )0 2 . (Mitscherlich, Ann. Ch. Phys. [3] iv. 
 73. E. Kopp, Compt. chim ; 1849, p. 146 ; Coinpt. rend. liii. 634. J. Wolff, Ann. Ch. 
 Pharm. Ixxv. 303.) This acid is produced by the action of strong nitric acid on cin- 
 
988 CINNAMIC ACID. 
 
 mimic acid (Mitscherlich, Kopp), or by heating styrone with nitric acid, to which 
 iireais added to prevent formation of nitrous acid (Wolff). To prepare it, concen- 
 trated nitric acid is freed from nitrous acid by boiling, and after cooling, about one- 
 eighth of ciunamic acid is added. The cinnamic acid dissolves in a few minutes without 
 disengagement of gas, the liquid becomes heated to 40 C., and a mass of crystals is 
 deposited. In order to obtain larger quantities, cinnamic acid is triturated with nitric 
 acid and cooled, so that the temperature may not rise above 60 ; the mass is washed 
 with cold water, till all nitric acid is removed, then dissolved in boiling alcohol and 
 filtered; and the resulting crystals are washed with cold alcohol (Mitscherlich). 
 Kopp dissolves 1 pt, of powdered cinnamic acid in 3 pts. of monohydrated nitric acid 
 freed from nitrous acid by passing a dry stream of air through it, the mixture then so- 
 lidifying almost immediately, in consequence of the crystallisation of the nitrocinnamic 
 acid ; washes the magma with water ; then dries, and sets it aside for twenty-four hours 
 with 4 pts. of cold alcohol, which removes any benzoic acid that may be present. 
 
 The acid forms very small white crystals, with a faint yellowish tint. It melts at 
 about270C., and solidifies toamass of crystals on cooling; boils a little above 270, with 
 decomposition. It is nearly insoluble in cold water, and dissolves but sparingly in boil- 
 ing water ; 1 pt. of it dissolves in 327 pts. of absolute alcohol at 20 C. Boiling hydro- 
 chloric acid dissolves it without decomposition (Mitscherlich.) With sulphide of 
 ammonium it forms carbostyril. When it is dissolved in alcoholic sulphide of ammo- 
 nium, sulphur separates on gently warming the liquid, while a yellow resin and an alka- 
 loid remain dissolved. Nitrocinnamic acid may be boiled with excess of alkali without 
 decomposition. 
 
 Nitrocinnamic acid is but a feeble acid ; nevertheless it forms neutral salts, and 
 decomposes alkaline carbonates. The nitrocinnamates of the alkali -metals are very 
 soluble, the rest are insoluble or sparingly soluble; they deflagrate when quickly 
 heated, especially the potassium- and sodium-salts. 
 
 Nitrocinnamate of Ammonium gives off its ammonia when evaporated to dryness; its 
 solution precipitates the salts of calcium, strontium, and magnesium when they are 
 concentrated, but not when they are dilute. 
 
 Nitrocinnamate of Barium, 2C 9 H 6 (N0 2 )Ba0 2 + 3aq., crystallises from a boiling 
 solution on cooling, in stellate groups of yellowish needles. The strontium-salt, 
 2C 9 H 6 (N0 2 )Sr0 2 + 5 aq., may be obtained in small yellowish crystals grouped in no- 
 dules ; it is moderately soluble in cold water. The calcium-salt, 2C 9 H 6 (N0 2 )CaO* -f- 3 aq., 
 forms small yellowish white agglomerated grains having a crystalline aspect. The 
 magnesium-salt, C 9 H 6 (N0 2 )Mg0 2 + 3aq., crystallises in yellowish white nodules, which 
 dissolve with tolerable facility in water, especially if warm. 
 
 Nitrocinnamate of Copper. Bluish-white precipitate, which becomes darker when 
 air-dried. When mixed with sand and distilled, it yields benzoic acid, nitrocinnamene 
 having the odour of oil of cinnamon, and a small quantity of nitrobenzene. 
 
 Mercuric Nitrocinnamate, C 9 H 6 (N0 2 )Hg0 2 , is thrown down from boiling solutions of 
 mercuric chloride and an alkaline nitrocinnamate, as a brownish anhydrous precipitate. 
 The mother-liquors deposit on cooling a crystalline mass of very light bulky arbo- 
 rescent tufts, consisting of the double salt, 2(IIgC1.2C 9 H b (N0 2 )Hg0 2 ) + 3aq. 
 
 Nitrocinnamate of Potassium. C 9 H S (N0 2 )K0 2 . Very soluble; crystallises in mamel- 
 lated groups by spontaneous evaporation. From solution in boiling alkaline ley, it 
 crystallises in prismatic needles. The sodium-salt resembles the potassium-salt. 
 
 Nitrocinnamate of Silver. C 9 H 6 (N0 2 )Ag0 2 . Yellowish white insoluble precipitate, 
 which, when cautiously heated, decomposes with projection of the silver. 
 
 NITBOCINNAMIC ETHERS. The ethyl-compound, C^'H^NO 4 = C 9 H 6 (N0 2 )(C 2 H 5 )0 8 , is 
 formed by heating nitrocinnamic acid with alcohol and sulphuric acid (Mitscherlich, 
 J. pr. Chem. xxii. T94), or by the action of strong nitric acid on cinnamate of ethyl 
 (E. Kopp, Cqmpt. rend. xxiv. 615). It crystallises in prisms, which melt at 136 C. ; 
 boils with decomposition at 300. Potash at the boiling heat converts it into alcohol 
 and nitrocinnamate of potassium. 
 
 Nitrocinnamate of Methyl C IO H 9 N0 4 = C 9 H 6 (N0 2 )(CH 3 )0'. (E. Kopp, Compt. 
 rend. liii. 636.) Obtained by heating nitrocinnamic acid with methylic alcohol, mixed 
 with a small quantity of sulphuric acid or saturated with hydrochloric acid gas. The 
 mixture thickens at first, then liquefies again, and finally a brown liquid is obtained, 
 from which the ether separates as a crystalline mass, which may be purified by pres- 
 sure and recrystallisation from alcohol. It forms white, delicate, rather elongated 
 needles, sparingly soluble in cold alcohol and ether, and having but little odour; melts 
 at 161 C. to a colourless liquid, which solidifies in a crystalline mass on cooling. At 
 about 200 C. it begins to sublime in iridescent crystalline plates, and at 200 it boils. 
 It dissolves in alcoholic sulphydrate of ammonium, forming a red liquid, which after- 
 wards turns brown, and when heated yields an abundant crystallisation of sulphur. 
 
CINNAMIC ALCOHOL CINNAMON, OIL OF. 989 
 
 CZXTHTAMZC ALCOHOIi. See CINNYLIC ALCOHOL. 
 CINNAMIC ALDEHYDE. See ClNNAMYL, HYDRIDE OF. 
 
 CINNAIVIIC ANHYDRIDE. C 18 H H 3 = (C 9 H 7 0) 2 .0. Cinnamate of Cinnamyl 
 Cinnamic Cinnamate, Anhydrous Cinnamic Acid. (Grerhardt, Ann. Ch. Phys. [3] 
 xxxvii. 285.) Produced by the action of oxychloride of phosphorus on well dried cin- 
 namate of sodium, the best proportions being 1 pt. of the former to 6 pts. of the latter. 
 The product is washed with water and carbonate of sodium, then dried and dissolved 
 in boiling alcohol. It may also be obtained by the action of chloride of cinnamyl on 
 neutral oxalate of potassium. It crystallises from the alcoholic solution as a white 
 crystalline substance, composed of microscopic needles. It is insoluble in cold alcohol, 
 and dissolves but slightly even in boiling water, becoming acid at the same time. It 
 melts at 127 C. 
 
 ACETO-CINNAMIC ANHYDRIDE. C 2 H 3 O.C 9 H 7 0.0. See ACETIC ANHYDRIDE (p. 21). 
 
 BENZO-CINNAMIC ANHYDRIDE. C 7 H 5 O.C 9 H 7 0.0. See BENZOIC ANHYDRIDE (p. 558). 
 
 NITROCINNAMIC ANHYDRIDE. C 18 H I2 N 2 7 = [C 9 H 6 (N0 8 )0] 2 .0. (Chiozza, Ann. 
 Ch. Phys. [2] xxxix. 231. Gerh. iii. 388.) Produced by the action of oxychloride 
 of phosphorus on nitrocinnamate of potassium. It melts in boiling water more easily 
 than nitrocinnamic acid, forming a yellow kneadable resin. It easily takes up water, 
 and is converted into nitrocinnamic acid. With ammonia, it easily forms nitrocinna- 
 mide and nitrocinnamate of ammonium. With alcohol, it forms nitrocinnamate of ethyl. 
 It is sparingly soluble in ether. 
 
 CIlffXTAMIC ETHERS. See page 986. 
 
 CINW AMIDE. C 9 H 9 NO = N.H*.C 9 H 7 p. Chloride of cinnamyl treated with dry 
 ammonia, yields sal-ammoniac, together with a white substance which dissolves in 
 boiling alcohol, and separates in delicate needles in cooling. (Cahours.) 
 
 NITROCINNAMIDE. C 9 H 8 N 2 3 = N.H 2 .C 9 H 6 (N0 2 )0. (Cahours, Ann. Ch. Phys. [3] 
 xxvii. 452.) Prepared : 1. By the action of aqueous ammonia on the product ob- 
 tained by treating nitrocinnamate of potassium with oxychloride of phosphorus. After 
 an hour's digestion at a gentle heat, the reaction is complete, and the nitrocinnamic 
 anhydride is completely transformed into nitrocinnamide and nitrocinnamate of am- 
 monium, which remains in solution. The nitrocinnamide is collected on a filter and 
 purified by crystallisation from boiling water. 2. By the action of alcoholic ammonia 
 on nitrocinnamate of ethyl ; this process, however, takes a long time, and requires a 
 large quantity of alcohol. 
 
 Nitrocinnamide separates from solution in boiling water in shortened, lustrous 
 needles, sometimes in grains and laminse having the appearance of flies' wings. It 
 melts and turns brown between 155 and 160 C., and decomposes completely at 260. 
 It dissolves sparingly in cold alcohol, moderately in ether, and separates from solution 
 in boiling alcohol in small, very regular, hemispherical concretions, smooth in the 
 upper, and nodular in the lower part. It dissolves in caustic potash, producing a red 
 solution, without evolution of ammonia. 
 
 PHENYL-CINNAMIDE. Cinnanilide. N.ILC 6 H 5 .C 9 H 7 0. (Cahours, Ann. Ch. Phys. 
 [3] xxiii. 344.) Produced by the action of phenylamine on chloride of cinnamyl. 
 It dissolves easily in hot alcohol, and separates in slender needles on cooling. It melts 
 at a gentle heat, and distils completely at a higher temperature. Potash-solution 
 scarcely attacks it, even with aid of heat ; but when fused with hydrate of potassium, 
 it gives off phenylamine. 
 
 NITRANISYL-CTNNAMIDE. Cinnitranisidine. C 16 H I4 N 2 4 = N.H.C 7 H 6 (N0 2 )O.C 9 H 7 0. 
 Produced by the action of chloride of cinnamyl on nitranisidine (p. 304). Yellowish 
 needles, sparingly soluble in cold, more soluble in boiling alcohol. (Cahours.) 
 CXNNAVTIXiXDE. Syn. with PHENYL-CINNAMIDE (vid. sup.) 
 
 CIinrHYDRAXttlDE. C 27 H 2 'N 2 = N 2 (C 9 H 8 ) 3 . A compound produced by the 
 action of ammonia on hydride of cinnamyL It is analogous to laydrobenzamide, 
 C 21 H 18 N 2 , and is therefore more properly called hydrocinnamide(j. v.) 
 
 CIWlffAIVIOIir, 0X1. OP, and Oil, OP CASSIA. These oils, which are nearly 
 identical in composition, are obtained from the bark of different trees of the genus 
 Cinnamomun, order Lauracets, viz. oil of cinnamon from Ceylon cinnamon, Cinnamn- 
 <mum Zeylanicum; and oil of cassia, from the bark of Chinese cinnamon, Cinnamomum 
 aromaticum, or from cassia buds, the undeveloped flowers of Cinnamomuni Laurcsii 
 (N e e s). The oils are prepared by softening the bruised bark or flowers with salt water, 
 distilling quickly, and drying with chloride of calcium. Oil of cinnamon has a more 
 agreeable odour than oil of cassia, and is therefore more esteemed. 
 
 Both the oils consist mainly of cinnamic aldehyde, which may be separated by means 
 of an acid sulphite of alkali-metal (p. 991); also a hydrocarbon, not yet examined, in 
 Variable, but always very small quantity, together with cinnamic acid, and resins. 
 
990 CINNAMON STONE CINNAMYL, HYDRIDE OF. 
 
 Old samples often deposit crystals of cinnamic acid. The density of the oils varies from 
 1-025 to 1-05 ; their boiling point from 220 to 225 C. 
 
 Resins from Cinnamon-oil. Old samples of the oil are more or less coloured and 
 charged with resinous matters, which remain, after the oil has been distilled with salt 
 water, the residue treated with cold water, to extract the salt, and afterwards with 
 boiling water, to extract cinnamic acid. According to Mulder (Ann. Ch. Pharm. 
 xxxiv. 149), there are two resins formed in the oil by atmospheric oxidation ; one, a, 
 soluble in cold alcohol, melting at 60 C., and containing 78-33 per cent, carbon, 6-49 
 hydrogen, and 15-18 oxygen ; the other, , sparingly soluble only in hot alcohol, melt- 
 ing at 145, and containing 83-45 per cent. C, 6-06 H, and 10-49 0. 
 
 Mulder likewise describes several other resins, some soluble, others insoluble in al- 
 cohol, produced by treating oil of cinnamon with sulphuric acid, hydrochloric acid, and 
 ammonia : they have all nearly the same composition as the /3-resin, produced by at- 
 mospheric oxidation. (Grin. xiii. 264.) 
 
 CI3VrJ'AlVIO3?J-STOWE. A variety of garnet (g_. v.) 
 
 CINNAiynrii. C 9 H 7 0. The monatomic radicle of cinnamic acid and its deriva- 
 tives. The following is a list of its compounds, and of those of the derived radicles, 
 chlorocinnamyl, &c. 
 
 Type HH : 
 Chloride of Cinnamyl . ...... C 9 JPO.C1 
 
 Cyanide of Cinnamyl ........ C 9 H 7 O.Cy 
 
 Hydride of Cinnamyl : Cinnamic Aldehyde .... C 9 H 7 O.H 
 
 Hydride of Tetrachlorocinnamyl : Chlorocinnose . . C 9 H 3 C1 4 O.H 
 
 Type HHO : 
 
 Hydrate of Cinnamyl : Cinnamic Acid . . . C n H 7 O.H.O 
 Hydrate of Bromocinnamyl : Bromocinnamic Acid . C 9 H 6 BrO.H.O 
 Hydrate of Chlorocinnamyl : Chlorocinnamic Acid . C 9 H G C10.H.O 
 Hydrate of Nitrocinnamyl : Nitrocinnamic Acid . C 9 H 8 (N0 2 ) 2 O.H.O 
 Oxide of Cinnamyl : Cinnamic Anhydride .... (C 9 H 7 0) 2 O 
 Oxide of Cinnamyl and Acetyl : Aceto-cinnamic Anhy- 
 
 dride ......... C 9 H 7 O.C 2 H 3 0.0 
 
 Oxide of Cinnamyl and Benzol : Benzo-cinnamic Anhy- 
 
 dride ......... C 9 H 7 O.C 7 H S 0.0 
 
 Oxide of Nitrocinnamyl : Nitrocinnamic Anhydride . [C 9 H 6 (N0 2 )0] 2 
 
 Cinnamide ........ N.H*.C 9 H 7 
 
 Phenyl-cinnamide : Cinnanilide .... N.H.C 6 H 5 .C 9 H 7 O 
 
 Nitranisyl-cinnamide : Cinnitranisidine . N.H.C 7 H 6 (N0 2 )O.C 9 H 7 
 
 The compounds of cinnamyl are intimately related to those of benzoyl, C 7 H 5 0, and 
 are easily converted by oxidising reagents into hydride of benzoyl and benzoic acid. 
 Cinnamic acid heated with excess of hydrate of potassium, is resolved, with evolution 
 of hydrogen, into acetic and benzoic acids (p. 984). 
 
 CIN3XTAIVTYI,, CHLORIDE OP. C 9 H 7 O.C1. (Cahours, Ann. Ch. Phys. [3] 
 xxiii. 341. Be champ, Compt. rend. xlii. 224.) This compound is produced by the 
 action of trichloride or pentachloride of phosphorus on cinnamic acid. When the 
 pentachloride is used, the product is distilled, the portions which pass over between 
 250 and 265 C. being collected apart and rectified (Cahours). With the trichlo- 
 ride, the mixture must be heated to between 60 and 120 C., as long as hydrochloric 
 acid continues to escape. It then melts and forms two layers, the upper of which, 
 consisting of chloride of cinnamyl, is decanted and distilled. (B 6 champ.) 
 
 Chloride of cinnamyl is a heavy oil, of specific gravity 1-207, boiling at 262 C. In 
 a moist atmosphere it decomposes quickly, yielding hydrochloric acid and fine crystals 
 of cinnamic acid. In contact with alcohol, it becomes strongly heated, and if water 
 be then poured upon the mixture, cinnamate of ethyl separates as a heavy oil. With 
 ammonia and phenylamine, it yields cinnamide and phenyl cinnamide respectively. 
 Heated with cinnamate of sodium, it yields cinnamic anhydride. 
 
 CINNAMYI., CTANIBE OP. C'H 7 NO = C 9 H 7 O.Cy. (Cahours, loo. tit.) 
 Produced by distilling chloride of cinnamyl with cyanide of potassium or cyanide 
 of mercury. A liquid then passes over, which rapidly turns brown when exposed to 
 the air, yielding hydrocyanic and cinnamic acids. It still contains chlorine, but con- 
 sists for the most part of cyanide of cinnamyl. 
 
 CXN-fiTAXOTTL, HYDRIOE OP. C 9 H 8 = C 9 H 7 O.H. Cinnamic Aldehyde. 
 (Dumas and Peligot, Ann. Ch. Phys. Ivii. 305. Mulder, Ann. Ch. Pharm. xxxiv. 
 
CINNAMYL: HYDRIDE. 991 
 
 147. -Bertagnini, ibid. Ixxxv. 272. Gm. xiii. 268. Gerh. iii. 373.) This com- 
 pound forms the essential part of oil of cinnamon or oil of cassia, and may be sepa- 
 rated therefrom by the action either of nitric acid or of the acid sulphites of the 
 alkali-metals. 
 
 a. When commercial oil of cinnamon is shaken up with strong nitric acid, large 
 crystals are formed, after two or three hours, consisting of a compound of nitric acid 
 with cinnamic aldehyde, which, when collected on a filter, so as to allow the still liquid 
 portion to drain off, and then decomposed by water, yields pure cinnamic aldehyde. 
 (Dumas and Peligot.) 
 
 b. Oil of cinnamon is agitated with three or four times its volume of a solution of 
 acid sulphite of potassium of 28 30 Bm ; and the crystalline mass, which forms in a 
 few minutes, is separated from the mother-liquor, left to dry on a filter, then pulverised, 
 washed with cold alcohol, again dried, and dissolved at a gentle heat in dilute sul- 
 phuric acid. A large quantity of sulphurous acid is then given off, and the cinnamic 
 aldehyde rises to the surface as an oil, which may be purified by washing and drying. 
 
 Cinnamic aldehyde is a colourless oil rather heavier than water. It may be distilled 
 without decomposition, either in vacuo, or with water which has been freed from air by 
 boiling. When exposed to the air, it quickly becomes yellow and resinous, and ac- 
 quires an acid reaction. It rapidly absorbs oxygen gas, especially if moist, and is 
 thereby converted into cinnamic acid. Heated with nitric acid, it forms benzoic acid 
 and hydride of benzoyl. Chromic acid converts it into benzoic and acetic acids 
 (Persoz). Boiled with solution of hypochlorite of calcium, it yields benzoate of 
 calcium. Strong sulphuric acid converts it into a resinous mass. 
 
 Cinnamic aldehyde gradually heated in a stream of chlorine, forms at first a liquid 
 compound, which solidifies when treated with a strong solution of potash. When dis- 
 tilled four or five times in a stream of chlorine, it is converted into tetrachlorocinnamyl. 
 With pcntachloride of phosphorus, it yields hydrochloric acid and chloride of cinnamyl. 
 Fused with hydrate of potassium, it forms cinnamate of potassium, with evolution of 
 hydrogen : 
 
 C 9 H 8 + KHO = C 9 H 7 K0 2 + H 2 . 
 
 Ammonia-gas converts it into cinnhydramide : 
 
 3C 9 H 8 + 2NH 3 = C 27 H 24 N 2 + 3H 2 0. 
 
 Compounds of Cinnamic Aldehyde. 
 
 a. With, Hydrochloric Add. Oil of cinnamon absorbs a large quantity of hydro- 
 " chloric acid gas, acquiring a green colour and becoming thicker. 100 pts. of the oil 
 
 take up 26-9 pts. of hydrochloric acid. 
 
 b. With Iodine and Iodide of Potassium. When cinnamon- water is placed in con- 
 tact with iodine and iodide of potassium and cooled to C., a crystallisable compound, 
 C 9 H 8 O.I 6 .KI, is formed. It crystallises from alcohol and ether, but water decomposes 
 it, setting free the cinnamic aldehyde. An excess of iodide of potassium prevents the 
 decomposition. (Apjohn, Ann. Ch. Pharm. xxviii. 314.) 
 
 c. With Nitric Acid. C 9 H 8 O.HN0 3 . Produced when strong nitric acid is left in 
 contact with cinnamic aldehyde. It forms oblique, rhomboi'dal prisms, often two or 
 three inches long. After being drained, they may be preserved for some hours, but 
 the least rise of temperature or atmospheric humidity quickly decomposes them. When 
 treated with water, they yield pure cinnamic aldehyde. 
 
 Nitrate of cinnamic aldehyde kept in an imperfectly closed vessel, yields after a few- 
 days a red liquid, which has the characteristic odour of bitter-almond oil, is converted 
 by ammonia-gas into nitrate of ammonium and a red resin ; and is dissolved by strong 
 sulphuric acid, the solution yielding with water a precipitate of cinnamic acid. 
 
 d. With Acid Sulphites of Alkali-metals. Cinnamic aldehyde dissolves easily in 
 aqueous acid sulphite of ammonium, forming an oily liquid, which afterwards solidifies 
 to a crystalline pulp. Oil of cassia shaken up with a strong solution of acid sulphite of 
 ammonium soon solidifies to a yellow crystalline mass, which may be purified from the 
 hydrocarbon and other substances which the oil contains, in addition to cinnamic al- 
 dehyde, by washing with alcohol of 80 or 90 per cent. (Gossmann). The compound 
 is very unstable, quickly turning brown, even when kept in closed vessels. 
 
 The potassium-salt is obtained by agitating oil of Ceylon or Chinese cinnamon with 
 three or four times its volume of a solution of acid sulphite of potassium of 28 to 
 30 Bm. ; after washing with alcohol and recrystallisation from boiling alcohol, it 
 forms beautiful silvery plates nearly inodorous and permanent in the air. It is soluble 
 in cold water, but the solution^ is decomposed by heat, giving off sulphurous acid and 
 yielding colourless drops of cinnamic aldehyde. Heated in a test-tube, it gives off 
 water, sulphurous acid, and cinnamic aldehyde, which, by contact with the air, is con- 
 verted into cinnamic acid. Bromine and iodine dissolve in the aqueous solution with- 
 
992 CINN YL CITRACONIC ACID. 
 
 out colouring it, but converting the sulphurous acid into sulphuric acid, and setting free 
 the cinnamic aldehyde. Bromine in excess produces a solid, slightly aromatic sub- 
 stance fusible in hot water. 
 
 Sodium-salt. Oil of cinnamon mixed with solution of acid sulphite of sodium of 
 37 Bm. forms a crystalline fibrous substance, which, if left to itself, soon becomes com- 
 pletely liquid ; at the same time there is formed an oil which is not solidified, either by 
 acid sulphites of alkali-metal or by nitric acid, the sulphite of cinnamyl-sodium appa- 
 rently remaining dissolved. The liquid, if left to evaporate, yields crystals of sulphate 
 of sodium, together with opaque crystalline nodules, which dissolve in boiling alcohol, 
 forming a solution which on cooling deposits long thin needles arranged in spiral 
 groups. (Bertagnini.) 
 
 HYDRIDE OF TETRACHLOROCINNAMYL. Chlorocinnose. C 9 H 3 C1 4 O.H. (Dumas 
 and Peligot, Ann. Ch. Phys Ivii. 316.) By repeatedly distilling hydrate of cinnamyl 
 in chlorine gas, this compound is obtained in long white very volatile needles. It melts 
 at a gentle heat and sublimes without decomposition. It is soluble in alcohol. It is 
 not decomposed by strong sulphuric acid, even at the boiling heat, and may be vola- 
 tilised without alteration in a current of dry ammonia. 
 
 The formation of this substance is preceded by that of several liquid compounds, one 
 of which, perhaps hydride of monochlorocinnamyl, solidifies in contact with potash-ley. 
 
 CINNYXi. C 9 H 9 . The radicle of the compound usually called cinnamic alcohol 
 or styrone. Cinnyl bears to cinnamyl, C 9 H 7 0, the radicle of cinnamic acid, the same 
 relation that ethyl, C 2 H 5 , bears to acetyl, C 2 H 3 0. 
 
 CXXirireXiXC ALCOHOL. C 9 H'0 = C 9 H 9 .H.O. Hydrate of Cinnyl, Cinnamic 
 Alcohol, Styrone, Styracone, Styrax- Alcohol, Styrylic Alcohol, Peruvin. (E. Simon, 
 Ann. Ch. Pharm. xxxi. 274. Toel, zfoW.lxx. 3. Strecker, ibid. Ixx. 10. J.Wolff, 
 ibid. Ixxxv. 299. E. Kopp, Compt. chim. 1850, p. 113. Scharling, Ann. Ch. Pharm. 
 cxv. 90, 183. G-m. xiii. 256. Gerh. iii. 402.) This compound is obtained by cau- 
 tiously distilling styracin with a strong solution of caustic potash or soda. A milky 
 liquid then passes over, from which, when saturated with common salt, a creamy sub- 
 stance separates, gradually collecting on the surface in an oily layer and solidifying 
 (Toel). Wolff dissolves styracin in boiling alcoholic potash; mixes water with the 
 liquid ; filters from cinnamate of potassium ; and separates the precipitated cinnamic 
 alcohol from undecomposed styracin by distillation. 
 
 Cinnylic alcohol forms beautiful soft silky needles, having a sweet taste and an 
 agreeable odour of hyacinths. It melts at 33 C., and volatilises without alteration at 
 a higher temperature. It is moderately soluble in water, very soluble in alcohol, in ether, 
 in styrol, and in oils, both fixed and volatile. When the aqueous solution saturated at 
 the boiling heat is left to cool, it becomes milky, and does not clarify for several hours, 
 when it becomes filled with needle-shaped crystals. 
 
 CIPOXiXHTO. A white marble with shadings or zones of green talc, found in Italy. 
 
 CISSAMPELINE. Syn. with PELOSINE (q. v.) 
 
 CITR-ACOlSr AMIDES and CXTZIACONANXX.XDES. See AMIDES OF Ci- 
 TRACONIC ACID (p. 993). 
 
 CITRACONIC ACID. Pyrocitric Acid. C 5 H 6 4 . (Lassaigne [1822], Ann. 
 Ch. Phys. xxi. 100. Dumas, ibid. cxi. 21. Eobiquet, ibid. Ixv. 78. Lie big, Ann. 
 Ch. Pharm. xxvi. 119, 152. Crasso, ibid, xxxiv. 68. Engelhardt, ibid. Ixx. 246. 
 
 Gottlieb, ibid. Ixxvii. 265. Baup, Ann. Ch. Phys. [3] xxxiii. 192. Gm. x. 417 
 
 Grerh. ii. 120.) This acid, or rather its anhydride, is produced by the dry distillation 
 of citric acid, constituting in fact the chief portion of the distillate (p. 995). The anhy- 
 dride rapidly attracts moisture, and when exposed to the air, is converted into a crystal- 
 line mass of citraconic acid, which is freed from excess of water by pressure between 
 blotting-paper and exposure to a temperature of 50 C. Citraconic acid is also one of 
 the products of the dry distillation of lactic acid. 
 
 Citraconic acid is inodorous, and has a sour and slightly bitter taste. It crystallises in 
 four-sided prisms, dissolves in 8 pts. of water at 10 C., and is readily soluble in alco- 
 hol and in ether. It melts at 80 C. ; small quantities of it kept for some time 
 at 100 are converted into itaconic acid. By dry distillation it is resolved into citra- 
 conic anhydride and water. 
 
 When citraconic acid is heated with strong nitric acid, a violent reaction is set up, 
 accompanied by disengagement of gas, and an oily body is produced, which on cooling 
 solidifies to a crystalline mass, consisting of two crystalline nitro-compounds, eulyto 
 and dyslyte, which dissolve in alcohol to an unequal extent ; their composition is 
 not known. By dilute nitric acid, citraconic acid is converted into mesaconic acid. 
 
 When bromine is gradually added to a strong solution of citraconate of potassium, car- 
 bonic acid is disengaged and a heavy yellowish oil separates, consisting of an acid and 
 a neutral substance. The former is removed by treatment with dilute potash, which 
 
C1TRACONIC ACID. 993 
 
 leaves the latter unaltered. When a weak acid is added to the alkaline solution, there is 
 separated, sometimes a heavy oil and sometimes fine needles. These two bodies are iden- 
 tical in composition, and consist of an acid, C 4 H tf Br 2 2 , which has been named by Ca- 
 hours, its discoverer, bromotriconic acid. It has the composition .of dibrominated butyric 
 acid (p. 693) ; but Cahours did not obtain it by the action of bromine on butyric acid 
 or butyrate of potassium. The liquid acid is slightly amber-coloured, and has a pecu- 
 liar odour. When distilled, it gives off hydrobromic acid and leaves a carbonaceous 
 residue. The liquid acid, after standing for some time, occasionally solidifies to a mass 
 of crystals. When it is heated with concentrated potash, a peculiar odour is disen- 
 gaged, and the addition of an acid no longer precipitates an oil. The acid forms a 
 curdy precipitate with silver-solution, and its ammonium-salt crystallises. 
 
 The neutral oil formed in the preparation of the acid has the composition C'^Bi^O, 
 and may either be tribromopropionic aldehyde or tribrominated acetone. 
 
 By the action of bromine on citraconate of potassium, in presence of excess of 
 hydrate of potassium, an oil is also separated and carbonic acid disengaged. When 
 a weak solution of potash is added, the greater part dissolves, and a small quantity 
 of tribromopropionic aldehyde remains ; on adding dilute nitric acid to the alkaline 
 solution, large white crystalline flakes are deposited, consisting of an acid which crys- 
 tallises from alcohol and ether in long prisms. It has the composition of dibromo- 
 propionic acid, C 3 H 4 Br 2 2 , but Cahours names it br omit on ic acid. 
 
 CITEACONATES Citraconic acid is a dibasic acid, and forms two series of salts, 
 the neutral salts, C 5 H 4 M 2 4 , and the acid salts, C 5 H 5 M0 2 ; they are isomeric with the 
 itaconates, mesaconates, and lipates. The acid salts mostly crystallise well. 
 
 The acid barium-salt, C 5 H 5 BaO', crystallises in large groups of fine silky needles, 
 
 The neutral silver-salt, C 5 H 4 Ag 2 0', crystallises both anhydrous and with an 
 atom of water. In an aqueous solution of citraconic acid, nitrate of silver produces, 
 on addition of ammonia, a very bulky precipitate which dissolves in boiling water. 
 On cooling, the salt is deposited in long needles. If the mother-liquor from this be 
 slowly evaporated, hexagonal crystals are formed which have an adamantine lustre, and 
 consist of the hydrated salt, C 5 H 4 Ag <2 4 + H 2 0. 
 
 The acid silver-salt, C 5 H 5 Ag0 4 , is obtained by dissolving the neutral salt in an 
 acid solution of citraconic acid. On evaporation, large groups of crystals are obtained. 
 
 Citraconate of Ethyl, or Citraconic Ether, C 9 H I4 4 , is obtained by repeatedly 
 cohobating a mixture of alcohol, citraconic acid, and hydrochloric acid, and washing the 
 distillate with water. 
 
 It is a colourless, bitter, somewhat aromatic liquid, of density 1*040 at 18-o C. It 
 boils at 225 C. with partial decomposition. It is insoluble in water, but readily soluble 
 in alcohol and in ether. In contact with water, it gradually acidifies and alcohol is 
 formed. By potash it is decomposed into citraconate of potassium and alcohol. E. A. 
 
 ACID, AIVIIDES OF: 
 
 CITRACONAMIDE, C 5 H 8 N 2 2 = N 2 .H 4 .(C 5 H 4 2 )", is obtained as a yellow* viscid 
 mass, which becomes brittle and vitreous on cooling, when citraconic anhydride is 
 heated in a stream of dry ammoniacal gas. It dissolves in water, and the solution on 
 cooling yields citraconate of ammonium. It is derived from neutral citraconate of am- 
 monium by the loss of 2 at. of water : 
 
 C 5 H 4 (NH 4 ) 2 4 - 2H 2 = C 5 H"N 2 2 . 
 
 CITRACONIMIDE. C 5 II 5 N0 2 = N.H.(C 5 H 4 2 )". Citraconic acid is mixed with 
 excess of ammonia and evaporated to dryness. and the residue heated to 180 C. Au 
 amorphous oily yellow mass is left, which is citraconimide. It does not dissolve in cold 
 water, and but slightly so in alcohol ; it is highly hygroscopic. It is derived from 
 acid citraconate of ammonium by the loss of 2 at. of water : 
 
 C 5 H 5 (NH 4 )0 4 - 2H 2 = C 5 H 5 N0 2 . 
 
 Phenylcitraconimide or Citraconanil. C"H 9 N0 2 = N.C 6 H 5 .(C 5 H 4 0-)". V\"hen 
 anhydrous citraconic acid is mixed with phenylamine, a brisk action ensues, and the 
 mixture, if kept for some time in the water-bath, is totally converted into the above 
 compound. It crystallises in colourless needles, which melt at 96 C., and sublime at 
 a little above 100. It is readily soluble in alcohol and in ether. 
 
 It is derived from acid citraconate of phenylamine by the loss of 2 at. of water : 
 C 5 H 5 (C 6 H"N)0 4 - 2H 2 = C"H 9 N0 2 . 
 
 lodophenylcitraconimidc, C M IPIN0 2 , is obtained by substituting iodophenylamine in 
 the above reaction. 
 
 Dinitrophenylcitraconimide, C U H 7 (N0 2 ) 2 N0 2 , is obtained by the action of a mixture 
 of nitric and sulphuric acid on phenylcitraconimide. 
 
 VOL. I. 3 S 
 
994 CITRACONIC ANHYDRIDE CITRIC ACID. 
 
 Citraconamic Acid. C 5 H 7 NCT = N.H-.C 5 H 4 2 .H.O. Citraconimide appears to 
 be partially convertible into this acid by boiling with ammonia. Its salts are un- 
 rrystallisable. 
 
 Phenylcitraconamic Acid, C n H"NO s = N.RC% 5 .C 5 H I 2 .H.O, is obtained as 
 an ammonium-salt by boiling pheuylcitraconimidewith dilute ammonia. On the addition 
 of acetic acid, it is separated as a crystalline precipitate, which is washed with cold 
 water. ' It is an unstable body. It is derived from acid citraconate of phenylamine 
 by the loss of an atom of water : 
 
 C 5 H 5 (C 6 H 8 N)0 4 - H 2 = C"H n NO s . 
 
 DinitropJienylcitraconamic acid, C n H 9 (N0 8 ) 2 NO 8 , is obtained in a similar manner. 
 
 E.A. 
 
 CITRACONIC ANHYDRIDE. C S H 4 S . This compound is produced by the 
 dry distillation of citric acid, constituting the greater part of the crude product. On 
 rectifying this crude distillate, two layers are formed, the upper being aqueous, and the 
 lower an oily acid liquid which does not solidify. This, which is citraconic anhydride, 
 is purified by redistillation. The same substance is formed by heating itaconic acid. 
 
 Citraconic anhydride is a colourless inodorous liquid of specific gravity 1-247. It 
 rapidly absorbs ammonia, with disengagement of heat, forming a vitreous deliquescent 
 mass, which probably consists of citraconamic acid. E. A. 
 
 CXTRACGWJC CHLORIDE. Pyrocitric Chloride, Chloride of Pyroritryf. 
 C 5 H 4 0'-C1 2 . "When pentachloride of phosphorus is mixed with citraconic anhydride, a 
 brisk action ensues, and on subsequent distillation, oxychloride of phosphorus passes 
 over, followed by chloride of pyrocitryl when the temperature has reached 175C. 
 It contains, however, some citraconic anhydride, which raises the boiling point ; it 
 is freed therefrom by redistillation with pentachloride of phosphorus, the part dis- 
 tilling between 175 190 being ultimately collected. It is a highly refracting fuming 
 liquid, with a density of T4. With water, it forms citraconic and hydrobromic acids, and 
 with absolute alochol, citraconic ether and hydrochloric acid. E. A. 
 
 CITRACOWIC ETHER. See ClTEACONATES (p. 993). 
 
 CZTR AMIDES. See page 1000. 
 
 CITRACONIMIDE (p. 993). 
 
 CITRACOBTZODANII,. Syn. With loDOPHENYLCITRACONIMEDE (p. 993). 
 
 CITREKTE. Citronyl. C 10 H 16 . A liquid isomeric with oil of lemon, &c., ob- 
 tained by distilling the solid di-hydrochlorate of lemon-oil over hydrate of potassiu7n 
 or quick lime. It is transparent and colourless, of specific gravity 0*8569, vapour- 
 density 4'73 (by calculation for 2 vol. 4*71) ; boils at 165 C. It resembles oil of lemon 
 in most of its properties, and in forming a crystallisable compound with hydrochloric 
 acid, but differs from it in being without action on polarised light. (Grm. xiv. 303.) 
 
 CITRIC ACID. C 6 H 8 7 = C 6 H 5 4 .H 3 .0 3 . (Scheele [1784], Opuscula ii. 181. 
 Berzelius, Ann. Chim. xciv. 171; Ann. Ch. Phys. lii. 424, 432; Ixvii. 303; Ixx. 
 215. Robiquet, ibid. Ixv. 68. Liebig, Ann. Ch. Pharm. v. 134; xxvi. 119, 452 ; 
 xliv. 57. Marchand, J. p. Chem. xxiii. 60. Cahours, Ann. Ch. Phys. [3] xix. 
 488. Pebal, Ann. Ch. Pharm. Ixxxii. 78; xcviii. 67. Grm. xi. 436. Gerh. ii. 85.) 
 The existence of a peculiar organic acid in the juice of lemons and of oranges has 
 long been known, but the discovery of the separate identity of this acid, and its dis- 
 crimination from tartaric acid, was first effected by Scheele in 1784, who gave to it 
 the name it bears. 
 
 It is to the presence of citric acid that a great many fruits owe their acidity. This 
 acid occurs in the free state in oranges, lemons, citrons, tamarinds, cherries, cur- 
 rants, gooseberries, raspberries, strawberries, whortleberries, and a great many others. 
 In some of them it is associated with malic and tartaric acids. It is also contained 
 in several tubers and bulbs, such as the potato and the onion. Occasionally it occurs 
 as acid potassium or calcium salt. 
 
 Preparation. The raw material for the production of citric acid is lemon juice. 
 The juice is made to undergo an incipient fermentation ; it is then filtered and 
 neutralised, first with chalk and afterwards with quick lime, by which an insoluble 
 citrate of calcium is formed: 10 pts. of this salt are carefully decomposed by a cold 
 mixture of 9 pts. sulphuric acid and 66 of water ; the gypsum is washed with cold 
 water ; and the filtrate and wash- water are boiled down in a leaden vessel over the naked 
 fire until the liquor has the specific gravity 1-13, then concentrated 'over a water-bath 
 until a saline film begins to form, when the liquid is immediately cooled to the crystallis- 
 ing point ; if it were further concentrated, the excess of sulphuric acid would convert 
 the residue into a black mass. The crystals formed are purified by four or five recrys- 
 
CITKIC ACID. 995 
 
 tallisations, and the mother-liquors are utilised for the preparation of citric acid by 
 treatment with chalk, in the same manner as the fresh lemon juice. In the south 
 of France, the citrate of calcium is bleached with chloride of lime, prior to its decom- 
 position with sulphuric acid. Good lemons yield about 5 per cent, of the crystallised 
 acid. 
 
 The raw material generally used in this country for the preparation of citric acid 
 on the large scale, for the use of calico-printers, is a black fluid, like thin treacle, 
 which comes from Sicily, and is obtained by inspissating the expressed juice of the 
 lemon after the rind has been removed for the sake of the essential oiL ( Ure's Dic- 
 tionary of Arts, Manufactures and Mines, i. 690.) 
 
 Citric acid may also be prepared from gooseberries. Tilloy (J. Pharm. xiii. 305) 
 expresses the juice of the unripe berries ; leaves it to ferment ; distils off the alcohol 
 formed ; filters the residual liquid ; and treats it with chalk in the same manner as in 
 the preparation of the acid from lemon juice. 100 pounds of gooseberries give 10 pounds 
 of spirit of specific gravity 0'928, and 1 pound of crystallised citric acid. 
 
 Properties. Citric acid crystallises in two forms. A concentrated solution deposits 
 by spontaneous evaporation, large, transparent, colourless prisms, having the composi- 
 tion C fi H 8 7 + H 2 ; this is the ordinary commercial acid. The crystals belong to 
 the trimetric system, and generally have the faces oo P . P oo . P oo predominant, also 
 with oo P oo ; the face 2p oo likewise occurs together with P oo, and sometimes without 
 it. P also not unfrequently occurs subordinate. Eatio of brachydiagonal, macrodia- 
 gonal, and principal axis = 0-6068 : 1 : 0-4106. (Kopp's Krystallographie, p. 264 J 
 see also Grerh. ii. 88.) The crystals effloresce in the air between 28 and 50 C., 
 and lose their water of crystallisation at 100. A boiling concentrated solution of 
 citric acid allowed to cool, deposits crystals of a different form, which, according to some 
 chemists, contain 2C 6 H 8 7 + IPO ; according to others, this water is only mechanically 
 mixed. 
 
 Citric acid has a strong, but pleasant, acidity, in which respect it differs from tar- 
 taric acid, the acidity of which is accompanied by a somewhat bitter taste. This dif- 
 ference is still greater in the salts. 
 
 Citric acid is soluble in 075 pts. of cold and in 0'5 pts. of boiling water. It is 
 readily soluble in alcohol, but insoluble in ether. 
 
 Citric acid and its potassium-salt are used in medicine. It is also used in the pre- 
 paration of effervescent summer beverages. Its most extensive application is in dyeing 
 and calico-printing ; for certain of the finer colours, it cannot be replaced by less costly 
 acids. 
 
 When lime-water is added to a solution of citric acid, a slight precipitate is formed, 
 if the solution is concentrated and the lime-water present in great excess. But if the 
 mixture be boiled, a considerable precipitate of citrate of calcium is formed, which re- 
 dissolves as the solution cools. By this deportment, free citric acid is easily detected. 
 It is distinguished from tartarie and racemic acids by the fact that its potassium-salt 
 is soluble. 
 
 D<.compositions. 1. Solution of citric acid, when kept for some time, becomes covered 
 with fungi. 2. An aqueous solution mixed with chalk and exposed for some time to a 
 temperature of 20 30 C. in contact with a little yeast, yields acetic and butyric acids. 
 According to How, when exposed in contact with putrefying curd and a base, it fer- 
 ments and becomes converted into acetic and propionic acids. 3. When citric acid is 
 heated in a retort, it first melts in its water of crystallisation and then boils, giving off 
 the water, which condenses in the receiver. Afterwards at about 175C. vapours of 
 acetone distil over, and a copious disengagement of carbonic oxide takes place. At this 
 time, the residxie in the retort consists of aconitic acid. If the distillation be con- 
 tinued, carbonic acid is given off and oily striae begin to appear in the neck of the retort, 
 which solidify to crystals ofitaconic acid. If these last crystals be repeatedly dis- 
 tilled, an oily mass of anhydrous citr aeon ic a c i d is obtained, which no longer solidi- 
 fies. These decompositions of citric acid are thus expressed : 
 
 - H 2 = C 6 H 6 6 . 
 
 Dry citric Aconitic 
 
 acid. acid. 
 
 - CO 2 = C 5 H 6 4 . 
 
 Aconitic Crystallised 
 
 acid. itaconic 
 
 acid. 
 
 C 5 H 6 4 - H 2 = C S H 4 8 . 
 
 Crystallised Citraconic 
 
 itaconic anhydride, 
 
 acid. 
 
 2S 2 
 
996 CITRIC ACID. 
 
 The acetone and carbonic oxide observed in an earlier stage of the decomposition 
 are probably due to a secondary decomposition of aconitic acid, thus : 
 
 C 6 H 6 8 - 2C0 2 + CO + C 3 H 6 0. 
 Aconitic Acetone, 
 
 acid. 
 
 Heated with pumice, citric acid gives offcarbonic anhydride at 153 C. 4. Fused with 
 potash, citric acid is decomposed into oxalic and acetic acids : 
 
 C a H 8 7 + H 2 = C 2 H 2 + 2C 2 H 4 2 . 
 
 Citric Oxalic Acetic, 
 
 acid. acid. acid. 
 
 5. When citric acid is treated with strong sulphuric acid, a disengagement of carbonic 
 oxide ensues, even without the application of heat. But if the temperature be raised, 
 the odour of acetone is perceived, and carbonic anhydride is given off. On adding 
 carbonate of sodium to the residual liquid diluted with water, a brown resinous mass 
 is precipitated, and the solution contains the sodium-salt of a peculiar acid, which does 
 not precipitate baryta or strontia. 6. Citric acid is not attacked by dilute nitric 
 acid; but if heated for some time with strong nitric acid, it yields oxalic and carbonic 
 acids. 
 
 7. Citric acid is easily oxidised by permanganic acid. A solution of citric acid 
 mixed with sulphuric acid does not decolorise permanganate of potassium in the 
 cold ; but at 80 C. the citric acid is oxidised to carbonic acid and acetone : 
 
 2CH 8 7 + H 2 + O 10 = C 8 H 6 + 9C0 2 + 6H 2 0. 
 
 If a large excess of the permanganate be used, other products are likewise formed, 
 namely, a body which strongly irritates the eyes and respiratory organs, reduces per- 
 manganate of potassium at common temperatures, and is turned brown by alkalis, pro- 
 bably therefore acrolein, together with an acid closely analogous to acrylic acid. Finely 
 divided peroxide of manganese acts in the same way as the permanganate. (P e a n de 
 Saint G-illes, Ann. Ch. Phys. [3] Iv. 374.) 
 
 8. Chlorine acts but feebly on citric acid. When a layer of concentrated solution of 
 citric acid is exposed to the sunlight in a large globe filled with chlorine, the gas is 
 slowly absorbed, and an oil gradually separates, which after rectification is colourless, 
 has a sweetish burning taste, and a peculiar odour. It boils at 200 201 C., and 
 does not solidify at 0. It reddens litmus paper only after prolonged contact. Plan- 
 tamour, the discoverer of this body, assigns to it the formula C 8 Cl itt 3 ; when it is 
 agitated with water and cooled to + 6, a mass of crystals is formed, C 8 C1 I6 3 .3H 2 0, 
 which melt and give off their water at 15. The oil is attacked by potash, with for- 
 mation of a body, C 4 C1 4 K 2 4 . Stadeler considers the oil to be hexachlorinated 
 acetone C 3 C1 6 (p. 30), and the crystals to be a hydrate, C 3 C1 6 + H 2 O. Laurent 
 ascribes to the oil the formula C 5 C1 10 2 . 
 
 9. The action of chlorine on citrate of sodium, though not very energetic even in 
 sunshine, is different. Carbonic acid is disengaged, and the liquor becomes milky from 
 formation of an oil; at the same time, an acid citrate of sodium is formed, which crys- 
 tallises in stellate groups. The odour of the oil, at first sweetish, becomes gradually 
 more acrid. It is a mixture of several bodies. On rectification, chloroform first distils 
 over at 64 66 C.; the boiling point then rises to 188 190, and remains constant 
 for some time ; it then rises to 200, at which point the oil produced by the free acid 
 distils over. The intermediate product, on rectification, boils at 190. It is a colourless 
 and very fluid oil, of specific gravity 1'66, with a burning taste, an extremely irritating 
 odour, and exciting tears. It has the formula C 5 C1'0 2 . The action of alcoholic 
 potash on this oil yields chloride of potassium, and a very soluble potassium-salt 
 which crystallises in satiny scales ; it has the formula C 4 C1 4 K 2 4 . The same salt is 
 produced by the action of potash on the oil from the free acid. A corresponding 
 silver-salt is very unstable, and is readily reduced to the metallic state even in the cold. 
 The potassium-salt has the composition of that of a chlorinated succinic acid. The 
 mother-liquor from which the chlorinated oil has been deposited contains, besides 
 chloride of sodium, the sodium-salt of an acid which has the composition of succinic 
 acid but appears to be only isomeric with it. 
 
 10. When bromine is gradually added to solution of citrate of pote,3siuin., a brisk 
 disengagement of carbonic acid takes place ; and if the addition of bromine be continued 
 as long as gas is given off, and the excess of bromine carefully removed by potash, an 
 oil is precipitated which is a mixture of two bodies. The most volatile of these is 
 bromoform, CHBr 3 . The other has received from Cahours the name bromoxaform. 
 It consists of lustrous silky needles, which by spontaneous evaporation crystallise in 
 large colourless plates. They melt between 74 and 75 C., but are gradually decom- 
 posed by distillation. The formula of the body is G^HBr'O 2 (pentachlorinated pro- 
 
CITRIC ACID. 997 
 
 pionic acid) : it is decomposed by potash, with formation of bromide of potassium, oxalic 
 acid, and bromoform: 
 
 C^B^O 2 + 2KHO = 2KBr + C 2 H 2 4 + CHBr 3 . 
 Bromoxaform. Oxalic Bromoform. 
 
 acid. 
 
 11. Dried citric acid in contact with pentachloride of phosphorus, becomes heated, and 
 yields oxychlorocitric acid and oxychloride of phosphorus : 
 C 6 H 8 7 + PCI 5 = C 6 H 8 6 C1 2 + POC1 3 . 
 
 If the mixture be heated, hydrochloric acid is evolved, and chloride of citryl appears 
 to be formed : 
 
 C 6 H 8 6 C p + PC1 5 = C H 5 4 CP + POC1 3 + HC1 + H 2 0. 
 
 Chloride of 
 citryl. 
 
 If the heat be continued, the liquid assumes a deep cherry-red colour and then appears 
 to contain chloride of aconityl: 
 
 C 6 H 5 4 C1 3 + PC p = C H 3 3 CP + POC1 3 + 2HCL 
 
 Chloride of 
 aconityl. 
 
 Citrates. Citric acid is a strong acid. It reddens blue litmus paper and expels 
 carbonic acid from carbonates. An aqueous solution dissolves zinc and iron, with dis- 
 engagement of hydrogen. 
 
 Citric acid is tribasic. It may be derived from 3 at. water in which 3 at. hydrogen 
 are replaced by the triatomic radical citryl, C 6 H 5 4 . It therefore forms three series 
 of salts, in which 1, 2, or 3 at. hydrogen are replaced by metal, thus: 
 
 Citric acid. ....... (C 6 H 5 4 )'" 
 
 Acid monometallic citrate ...... (C 6 H 5 4 )' 
 
 H 2 .M 
 
 Acid dimetallic citrate ...... (C 6 H 5 4 )"' > ns 
 
 H.M 2 J U 
 
 Neutral trimetalHc citrate ...... (C 6 H 5 4 )'"J , 
 
 Some of the citrates occur naturally, as citrate of calcium in onions and potatoes, 
 and citrate of potassium in artichokes and potatoes. The alkaline citrates are very 
 soluble ; other citrates, as those of zinc, iron, cobalt and nickel are less so, while the 
 citrates of the alkaline earths are insoluble. In the presence of soluble citrates, alkalis 
 do not precipitate the salts of iron, manganese, or aluminium. The citrates decompose 
 when heated to 230C M forming empyreumatic products, which have not been investigated. 
 
 The following list includes all the principal citrates. 
 
 CITE ATE OF ALUMINIUM. Insoluble powder when it contains excess. of metal ; 
 soluble gum when the acid is in excess. 
 
 CITBATE OF AMMONIUM. Monammonic Citrate, C 6 H 7 (NH 4 )0 7 . Solution 
 of citric acid, neutralised with ammonia, and then mixed with twice as much acid as 
 it already contains, yields this salt by spontaneous evaporation in small triclinic 
 prisms. 
 
 Diammonic Citrate, C 6 H 6 (NH 4 ) 2 7 , crystallises on the evaporation of a solution 
 of citric acid which hfis been saturated by ammonia, in prisms which are anhydrous but 
 deliquescent. 
 
 CITRATES OF BARIUM. Tribarytic Citrate, C 6 H 5 Ba 3 7 . Citric acid added to 
 excess of baryta-water throws down flakes which become somewhat crystalline. White 
 powder ; dried in the cold, it contains water of crystallisation, which it gives off com- 
 pletely at 200 C. 
 
 Monobarytic Citrate 1 Obtained as a gummy mass by evaporating a solution of 
 barytic citrate in citric acid. 
 
 A crystalline citrate of barium which, dried at 160 C., has the formula C 12 H"Ba 5 14 , 
 is obtained by adding tribarytic citrate to a boiling transparent mixture of citric acid 
 and chloride of barium, as long as the resulting precipitate redissolves, and then allow- 
 ing the mixture to cool It appears to be a double salt of tribarytic and dibarytic 
 citrate. 
 
 Citrate of sodium is precipitated only by a large excess of chloride of barium : hence 
 citrate of barium must be somewhat soluble in citrate of sodium. 
 
 CITEATE OF CADMIUM. Crystalline sparingly soluble salt. 
 
 CITBATES OF CALCIUM. Tricalcic Citrate, C 6 H 5 Ca 8 7 + 2H 2 0. When 
 
 3 s 3 
 
998 CITRIC ACID. 
 
 chloride of calcium is gradually added to a solution of citrate of sodium, the precipi- 
 tate at first formed redissolves, but when agitated, it suddenly forms a magma which 
 becomes crystalline on the application of heat. The salt is more soluble in cold than 
 in hot water, so that a cold solution becomes turbid on being boiled. 
 
 Dicalcic Citrate, C 6 H 6 Ca 2 7 + IPO. Obtained in shining laminae by dissolving 
 the preceding compound in excess of citric acid, and evaporating the solution. 
 
 CITRATE OF CEKITJM. White insoluble powder, obtained by double decomposi- 
 tion of alkaline citrates and cerous salts. 
 
 CITRATE OF COBALT, C 6 H 5 Co s 7 + 7H 2 0. The solution of carbonate of cobalt 
 in warm citric acid, solidifies on cooling, after adequate evaporation, to a rose-coloured 
 magma, which dries up to a powder of the same colour. 
 
 CUPRIC CITRATE. Obtained in microscopic rhombohedra by heating a solution 
 of cupric acetate with citric acid. The formula is CH 5 Cu 3 7 .CuHO + H 2 O. 
 
 CITRATES OF!RON. Ferrous Citrate. Alcohol precipitates white flakes of 
 triferrous citrate from a clear solution of iron in citric acid. 
 
 Ferric Citrate. Freshly precipitated hydrated ferric oxide dissolves in warm 
 aqueous citric acid, forming a reddish-brown liquid which on evaporation leaves a 
 light-brown film. It is administered medicinally under this form. Ferrocyanide of 
 potassium does not precipitate an acid solution of ferric citrate, but forms a blue liquid 
 which is decolorised by ammonia. 
 
 Ammonio- ferric Citrate. (Ammonio-citrate of iron.) When 2 pts. of freshly 
 precipitated ferric hydrate are dissolved in 3 pts. of citric acid, the solution saturated 
 with ammonia leaves on evaporation a greenish-yellow mass, insoluble in strong alcohol, 
 but soluble in alcohol of 40 per cent. 
 
 CITRATE OF LITHIUM. Amorphous, limpid, hard mass. 
 
 CITRATES OF LEAD. Triplumbic Citrate, C 6 H 5 Pb s 7 (at 1 20 C.), is best ob- 
 tained by precipitating an alcoholic solution of plumbic acetate with an alcoholic 
 solution of citric acid, and washing the precipitate with alcohol ; it is granular when 
 hot solutions are employed. 
 
 Diplumbic Citrate. C 5 H G Pb 2 7 + H 2 0. A solution of acetate of lead is added 
 to a boiling dilute solution of citric acid as long as the precipitate redissolves. On eva- 
 porating the clear solution, the salt crystallises in small prisms. Ammonia dissolves 
 this salt, and the solution afterwards deposits triplumbic citrate. 
 
 Tetrabasic Salt. By digesting triplumbic citrate with ammonia, Berzelius ob- 
 tained a heavy white powder, which had the formula C 6 H 5 Pb 3 7 . PbHO, 
 
 PbO + HO). The triplumbic citrate digested with excess of subacetate of lead, gave 
 an insoluble amorphous powder, which had the formula C G H 5 Pb 3 7 .PbHO.Pb'-'O (or 
 <7 12 #W 0".3Pb + HO). Heldt obtained a salt of the formula 2(C fi H 5 Pb 3 7 .Pb 2 0) + 
 3H 2 0, or C l2 H 6 Pb 3 }t .2PbO + 3HO, by digesting triplumbic citrate with ammonia for 
 two days in a close vessel. Bulky, white, insoluble powder 
 
 CITRATE OF MAGNESIUM. C 6 H 5 Mg 3 7 + 7H 2 0. Carbonate of magnesium dis- 
 solves in citric acid to a solution which forms a thick magma when concentrated. Alcohol 
 precipitates the salt from its aqueous solution. 
 
 This salt, evaporated with excess of citric acid, yields a gummy mass, which does 
 not become crystalline. 
 
 When carbonate of magnesium is digested with disodic citrate, the filtered solution 
 on evaporation leaves small crystalline groups, which contain sodium and magnesium. 
 
 CITRATE OF MANGANESE. C 6 H 6 Mn 2 7 + H 2 0. Citrate of sodium does not 
 precipitate manganous salts ; but when carbonate of manganese is digested with citric 
 acid, the above salt is obtained as a white insoluble crystalline powder. 
 
 CITRATESOFMERCURT. Citric acid precipitates from mercuro us acetate, a white 
 powder soluble in nitric acid. 
 
 Freshly precipitated mercuric oxide dissolves in hot citric acid, and the solution on 
 cooling deposits a white powder, which is decomposed by water. 
 
 CITRATE OF NICKEL. C 6 H 5 Ni 3 7 + 7H 2 O. Oxide of nickel dissolves in citric 
 acid to a green liquid, gradually changing into a green jelly, which on evaporation 
 leaves an olive-green film, soluble in water but precipitated by alcohol. 
 
 CITRATES OF POTASSIUM. Tripotassic Citrate. C 6 H 5 K 3 7 + H 2 0. A 
 solution of carbonate of potassium neutralised with citric acid, yields by spontaneous 
 evaporation, transparent, stellate-grouped needles, very deliquescent, and insoluble in 
 absolute alcohol. They lose their water of crystallisation at about 200 C. 
 
 Dipotassic Citrate. C 6 H 6 K*0 7 . A solution of 2 pts. of citric acid neutralised 
 with carbonate of potassium, and mixed with 1 pt. of citric acid, yields by evaporation 
 an amorphous mass having a sour taste. 
 
CITRIC ACID. 099 
 
 Monopotassic Citrate. C fi H 7 K0 7 + 2H-0. 1 pt. of citric acid is neutralised 
 with potash, 1 pt. of citric acid added, and the mixture evaporated at 40 C. Large 
 transparent prisms, permanent in the air, and having an agreeable sour taste. They 
 melt in their water of crystallisation, and give off 13 -8 per cent, of water, forming a 
 viscous liquid, which solidifies on cooling to a concentric radiated mass of crystals, 
 consisting of C 6 H 7 K0 7 . 
 
 Ammonio-potassic Citrate. C 6 H 5 K 2 (NH 4 )0 7 . A solution of dipotassic citrate 
 neutralised with ammonia, yields this salt, on evaporation, in transparent deliquescent 
 prisms. 
 
 Potassio-antimonic Citrate. 1 pt. of citric acid is neutralised with potash ; 
 1 pt. more of acid added ; the mixture boiled for some time with trioxide of antimony, 
 and the filtrate left to crystallise. White, shining, very hard prisms, grouped in tufts. 
 They give off 67 per cent, of water at 190 C. May be regarded as a double molecule 
 of tripotassic citrate, in which part of the potassium is replaced by the tribasic radicle, 
 antimony : C 18 H 10 (K 3 Sb'")0 14 . 
 
 CITRATE OF SILVER. C 6 H 5 Ag 3 7 . Citrate of potassium added to solution of ni- 
 trate of silver, throws down this salt as a heavy white powder, which crystallises from 
 boiling water in white or yellowish needles. Deflagrates at a high temperature. 
 
 Argentous Salt. The above salt heated to 100C. in a current of hydrogen, is 
 changed into a dark brown mass, which is a mixture of citric acid and triargentous 
 citrate. Water extracts from this mass first citric acid, and then a small quantity of 
 argentous salt with a red colour. This red solution heated to boiling, assumes a green 
 and blue colour, then deposits metallic silver, and becomes decolorised. 
 
 CITRATES OF SODIUM. Trisodic Citrate. 2(C G H 5 Na 3 7 ) + 11H 2 0. When 
 a solution of citric acid is saturated with soda, and the solution left to evaporate, 
 large rhombic prisms are obtained of this composition. They quickly effloresce and 
 are sparingly soluble in alcohol. At 100 C. 7 at. water are given off, and at 190 
 200, 4 at. more. A solution of this citrate evaporated at 60 C., yields monoclinic 
 crystals containing only 2 at. water. 
 
 Disodic Citrate. C 6 H 6 Na 2 T .H 2 0. Obtained like the corresponding potassium- 
 salt. Prismatic, stellate-grouped crystals, which give off their water of crystallisation 
 when dried over oil of vitriol. 
 
 Monosodic Citrate. CsiTTSTaO 7 + H 2 0. Obtained like the corresponding po- 
 tassium-salt. A very concentrated solution left to evaporate in a warm place, solidifies 
 to a mass of acicular crystals, and crystallises to the last drop. 
 
 Ammonio-sodic Citrate. Confused crystalline crust. 
 
 Potassio-sodic Citrate. C fi H 5 Na 3 7 .C K H 5 K 3 7 + 11H 2 Obtained by dissolv- 
 ing equivalent quantities of trisoclic citrate and tripotassic citrate, and concentrating 
 by evaporation. It is deposited after some days in radiate-grouped, lustrous needles. 
 
 CITRATE OF STRONTIUM. Strontia-water is precipitated by citric acid in thick 
 white flakes, which, after drying over oil of vitriol, have the composition C 6 H 5 Sr 3 7 + 
 H 2 0. They lose their water of crystallisation at 210 C. 
 
 CITRATE OF ZINC. C 5 H 5 Zn 3 7 + H 2 0. Carbonate of zinc dissolves readily in 
 aqueous citric acid ; on boiling, the salt is precipitated as a granular, crystalline powder. 
 
 The aqueous solution of this salt mixed with a small quantity of citric acid, and 
 evaporated at a gentle heat, deposits transparent crystals, which have the composition 
 C 6 H 5 Zn 3 7 .C 6 H 6 Zn 2 7 + H 2 0. 
 
 Substitution-derivative of Citric Acid. 
 f P 6 TT 5 n*Y" ) PI 2 
 
 OXYCHLOROCITRIC ACID. C 6 H"C1 2 6 = ^ u . 3 j ^J . When pentachloride 
 
 of phosphorus is mixed with dry citric acid, the mass becomes heated, liquefies, and 
 then solidifies to a magma of crystals which consist of oxychlorocitric acid mixed with 
 oxy chloride of phosphorus. The latter is removed by digestion with disulphule of 
 carbon, the mass is thrown on a filter, and washed with disulphide, then pressed be- 
 tween bibulous paper, and dried in a current of hot air. It forms colourless silky 
 needles : 
 
 C 8 H 8 7 + PCI 5 = C 6 H 8 O fi Cl 2 + POC1 3 . 
 
 In moist air or in water, this acid becomes heated and is converted into citric acid. 
 
 On heating it in a stream of dry air to 100 C., hydrochloric acid is liberated, and the 
 residue consists of aconitic acid. Dry ammonia acts violently upon it, forming a black 
 vesicular mass. In contact with aniline, the acid becomes strongly heated, and yields 
 phenyl-aconitimide. E. A. 
 
 3 s 4 
 
1000 CITRIC ACID, AMIDES OF CITRIC ETHERS. 
 
 CITRIC ACID, A.TKI3>22S OP. (Pebal, Ann. Ch. Pharm. Ixxxii. 73; xcviii. 
 67.) Of the amides of citric acid, bodies derived from ammonia by the replacement of 
 hydrogen by the radicle citryl, only citramide is known ; but many of the correspond- 
 ing phenyl-compounds have been obtained by Pebal. 
 
 T) 
 
 V 
 
 CITEAMIDE. C 6 H U N 3 4 = VN 3 , is a crystalline compound, slightly so- 
 
 luble in water, obtained by the action of alcoholic ammonia on citrate of methyl or 
 citrate of ethyl. 
 
 (C 6 H 5 4 )'") 
 Phenylcitramide. Citranilide. (C 6 H 5 ) 8 VN S , is obtained by the action of heat 
 
 H 3 ) 
 on triphenylamic citrate : 
 
 C 6 H 5 (C 6 H 8 N) S 7 - 3H 2 = C 2 'H 23 N 3 4 . 
 
 Triphenylamic citrate. Phenylcitramide. 
 
 To prepare this body, the yellow powder left on heating triphenylamic citrate is dis- 
 solved in boiling alcohol, and the solution is decolorised by animal charcoal. On cooling, 
 two sets of crystals are deposited, hexagonal plates and fine prisms. The former consist 
 of phenylcitrimide, and are dissolved out by boiling with alkali, which does not per- 
 ceptibly affect the phenylcitramide. Phenylcitramide is deposited from alcohol in 
 colourless prisms, truncated longitudinarily, and with a nacreous lustre. Neutral to 
 vegetable colours. 
 
 (C 6 H 5 4 )'") 
 
 Phenylcitrimide. Citrobianil. C 18 N 2 H 16 4 = (C 6 H 5 )HN 2 , represents dipheny- 
 
 H j 
 lamic citrate minus 3 atoms of water : 
 
 C 6 H(C 6 H 8 N) 2 7 - 3H 2 O = C 18 H 16 N 2 4 . 
 
 Diphenylamic citrate. Phenylcitrimide. 
 
 It is obtained in the preparation of phenylcitramide ; also by heating phenylcitramic 
 acid with phenylamine : 
 
 C i2 H !i N0 5 + c fi H 7 N = C I8 H 16 N 2 4 + H 2 0. 
 
 Phenylcitramic Phenylamine. Phenyl- 
 acid. citrimide. 
 
 Hexagonal plates, soluble in alcohol, and converted by boiling with ammonia into di- 
 phenylcitramic acid. 
 
 Phenylcitramic Acid. Citranilic Acid. C 12 H n N0 5 = N (C 6 H 5 )(C 6 H 5 a' )'" ) Q _ 
 Obtained by the action of heat on monophenylamic citrate : 
 
 C 6 H 7 (C 6 H 8 N)0 7 - 2H 2 = C 12 H U NO S . 
 
 Monophenylamic Phenyl- 
 
 citrate. citramic acid. 
 
 Monophenylamic citrate is heated to 140 150 C. as long as water is given off. On 
 cooling, the residue becomes crystalline. It dissolves readily in water, and if excess of 
 phenylamine has been avoided, it is deposited in small crystalline spherules, or in 
 mamillary groups of small prisms. It has an acid reaction, and forms crystalline salts 
 with silver and with aniline. 
 
 On treating it with pentachloride of phosphorus, hydrochloric acid is given off, 
 and a liquid formed, which appears to contain chloride of aconitanyl, C I8 NH 8 3 .C1, as, 
 when treated with water, it is resolved into hydrochloric acid and phenylaconitamic 
 acid. 
 
 Diphenylcitramic Acid. Citrobianilic Add. C I8 H 18 N-0 5 . 'Obtained in the 
 form of an ammonia-salt by boiling phenylcitrimide with ammonia. By adding hydro- 
 chloric acid to the solution, the acid is precipitated. Recrystallised from alcohol, it 
 forms soft,concentrically-grouped,silky needles. It melts and gives off water at 150 C., 
 and becomes reconverted into phenylcitrimide. 
 
 Diphenylcitramic acid contains the elements of diphenylamic citrate minus 2 at. 
 water : C 8 H 6 (C 6 H 8 N) 2 7 - 2H 2 = C 18 H 18 N 2 5 , and may be represented by the 
 
 formula (C 6 H 5 4 )'" ^, derived from the mixed type N 2 H 6 .H 2 0. E. A. 
 
 CITRIC ETHERS. The citric ethers represent citric acid in which one or more 
 atoms of hydrogen are replaced by alcohol-radicles. Those in which one or two 
 atoms of hydrogen are thus replaced have acid properties. 
 
CITRIDIC ACID CITROMANNITANS. 1001 
 
 CITBATB OF METHYL. Trimethylic Citrate. C 9 H I4 7 
 
 A solution of citric acid in wood-spirit is saturated with hydrochloric acid gas ; on recti- 
 fying the mixture, chloride of methyl and the excess of wood-spirit pass off, and a 
 colourless liquid distils over at about ,90 C., which is citrate of methyl. After standing 
 some time it crystallises. (Saint- Evre, Compt. rend. xxi. 144.) 
 
 Monomethylcitric Acid, ^?CIP "| 3 ' and J)imetji y lcitric <*&#> 
 
 ate both formed in the preparation of citrate of methyl. They have been but little 
 examined. (Demon desir, Compt. rend, xxxiii. 227.) 
 
 CITBATE OF ETHYL. Citric Ether. [Q!^^ ?0 3 . (Thenard, Mem. d'Ar- 
 
 cueil, ii. 12. Malaguti, Ann. Ch. Phys. Ixiii. 197. Dumas, Compt. rend. viii. 528. 
 Marchand, J. pr. Chem. xx. 318. Heldt, Ann. Ch. Pharm. xlvii. 57. Dexnon- 
 desir, loc. tit.) This body is formed by distilling a mixture of sulphuric acid, citric 
 acid, and alcohol ; but the best method of preparing it, according to Demondesir, is as 
 follows : A solution of citric acid in alcohol is saturated with hydrochloric acid gas, 
 the liquid neutralised with carbonate of soda, and agitated with common ether, which 
 dissolves out the citric ether. On evaporating the ethereal solution, citric ether is left 
 as an oily, yellowish, transparent liquid, with an odour resembling olive oil. Its spe- 
 cific gravity is 1-142. It is very soluble in alcohol and in ether. It boils at 280 C., 
 but decomposes probably into aconitic or citraconic ether. It is decomposed by free 
 alkalis into citrates and free alcohol. With ammonia it yields, besides citramide, 
 several products which have not been examined. E. A. 
 
 CITRIDIC ACID. Syn. with ACONITIC ACID. 
 
 CITRILEItfE. See CITEENE. 
 
 CITRINE, A glassy variety of quartz having a wine-yellow colour. 
 
 C I THINS. Citroglycerins. Citrates of Glyceryl. ( v a n B e m m e 1 e n, J. pr. Chem. 
 Ixix. 84.) Two of these compounds have been obtained by heating citric acid with 
 glycerin. 
 
 Neutral Citrate of Glyceryl, C 9 H 10 7 = / 3 ' is P re P ared b y heat 
 
 ing citric acid with a slight excess of glycerin to 160 170 C. for twenty hours. 
 Water then escapes, and there remains a hard, light yellow, transparent mass, from 
 which the pure product may be obtained by boiling out the excess of glycerin with 
 alcohol. It is difficult to pulverise ; insoluble in water, alcohol, and ether. Hydro- 
 chloric acid dissolves it gradually with aid of heat ; sulphuric acid immediately, with 
 blackening. It dissolves gradually in cold potash-ley, and when boiled with bases, is 
 quickly resolved into citric acid and glycerin. The formation of the compound is re- 
 presented by the equation : 
 
 C 6 H 8 O 7 + C 3 H 8 3 = C 9 H 10 7 + 3H 2 0. 
 
 Citric acid. Glycerin. 
 
 Basic Citrate of Glyceryl. Citrodiglyceride, C I2 H 18 10 = C 9 H 10 7 .C 8 H 8 S , 
 may be regarded as a double molecule of glycerin ( -erg |0 6 Y in which 3 at. hydro- 
 
 (CH'o)" -. 
 gen are replaced by citryl, that is to say, as (C 6 H S 4 )'" [ O 6 . Obtained like the pre- 
 
 H s ) 
 
 ceding, by heating citric acid with a double quantity of glycerin. The mass melts at 
 -100C., and the transformation is completed between 160 and 170. The product 
 purified by boiling with alcohol, is yellowish -brown, somewhat darker and less hard 
 than the neutral compound, which, however, it resembles in other respects. 
 
 CITROCERIC and CITROIiIC ACIDS. Two acids said to be contained in 
 the sediment of lemon and bergamot oils; the former is waxy, the latter oily. (My- 
 lius, Arch. Pharm. xxxii. 28.) 
 
 CITRODIANIX.. Syn. With PHENYLCITKIMIDE (p. 998). 
 
 CITROGLYCERIKT. See CITRINS. 
 
 CITR01VIA.JWWITANS. (v. Bemmelen, Jahresber. d. Chem. 1858, p. 435.) 
 This term is applied to two compounds derived from mannite in the same manner as 
 the citrins are derived from glycerin. They are formed by heating citric acid with 
 mannite in proper proportion to between 130 and 140 C., combination then taking 
 place, attended witli elimination of water. 
 
1002 CITRON, OIL OF CITRUS. 
 
 fi )^> 
 Monocitromannitan. C 12 H 14 9 =(C 6 H 5 4 )'"V0 5 = C 6 H 8 7 -h C 6 H 12 5 - 3H -0. 
 
 H 3 ) 
 
 A hard, light yellow, tasteless substance, insoluble in cold water, alcohol, and ether, 
 decomposed by long boiling with water or alcohol, also by alkalis. Between 170 and 
 180 C. it turns brown and decomposes. 
 
 Dicitromannitan. C 18 H 20 15 = (C 6 H s 4 )"'y0 5 + 2H-0. Obtained as a hy- 
 
 (C 6 H S 4 )'") 
 
 drate by heating 2 at. citric acid and 1 at. mannite for some time to between 140 and 
 150 C. The product is a dry, hard, light yellow mass, which has no acid reaction, 
 dissolves in water only after long boiling, is easily decomposed by alkalis, and does 
 not give off water without decomposition when heated. 
 
 CITRON, OIIi OP. See CITRUS MEDICA (p. 1004). 
 
 CITRONYl. The name applied by Blanchet and Sell to that constituent of 
 lemon-oil, which forms a crystallisable compound with hydrochloric acid (p. 1004). It 
 is sometimes also applied to the triatomic radicle of citric acid. 
 
 CITROPTENE. The camphor or stearoptene of lemon-oil (p. 1004). 
 
 CITRUS. A genus of plants belonging to the natural order Aurantiacea, and 
 including the orange, lemon, citron, shaddock, &c. They all produce juicy fruits con- 
 taining citric acid, and enclosed in a thick fleshy rind containing volatile oils, which 
 are isomeric with oil of turpentine, but differ from one another in odour, density, ac- 
 tion on polarised light, &c. 
 
 CITRUS AURANTIUM. The Sweet Orange. The rind of this fruit contains a 
 volatile oil, Oil of orange-peel, Oleum corticum aurantiorum, which may be extracted 
 by pressure or by distillation with water. It has the same composition and vapour- 
 density as oil of lemon. Specific gravity in the liquid state 0'83 0*89. Boiling 
 point 180C. It is neutral, and has an agreeable odour. Optical rotatory power, 
 125-6 127*4 to the right. It dissolves completely in absolute alcohol, and with 
 turbidity in 7 10 pts. alcohol of specific gravity 85. It unites with hydrochloric 
 acid, forming a liquid compound, C 10 H !6 .IIC1, and a solid compound, C 10 H' 6 .2HC1, 
 which melts at 50 C. (Grm. xiv. 306.) 
 
 Orange-peel also contains, especially in the unripe state, a bitter principle called 
 Aurantiin or Hesperidin (q. v.) 
 
 The juice of the orange contains citric and malic acids, partly free, partly combined 
 with bases. The juice of sweet oranges likewise contains grape-sugar or cane-sugar ; 
 the grape-sugar predominates in the unripe state, but does not sensibly increase in 
 quantity as the fruit ripens, while the amount of cane-sugar increases, both absolutely 
 and relatively to the weight of the orange, the juice, and the solid constituents (Ber- 
 thelot and Buignet, Compt. rend. li. 1094). 100 pts. of oranges contain 4-2 per 
 cent, cane-sugar, 4-3 grape-sugar, and 0'45 free acid (Buignet, Ann. Ch. Phys. Ixi. 
 233). The pips of the orange contain a bitter substance, which appears to be identical 
 with the limonin of lemon-pips. 
 
 The flowers of the orange contain a very fragrant volatile oil, called Oil of Neroli, 
 Oleum florum naphce s. neroli, which is obtained by distilling the flowers with water. 
 When recently prepared, it is nearly colourless, but reddens quickly on exposure to 
 light. According to Soubeiran and Capitaine, it is composed of two oils, one easily 
 soluble in water and very fragrant, while the other is sparingly soluble and has a less 
 agreeable odour ; the latter floats on the watery distillate, and is easily separated. The 
 more fragrant oil may be extracted from the watery distillate (orange-flower water] by 
 means of ether. It is reddened by sulphuric acid, and communicates this property to the 
 entire essence. Nitric acid colours the oil brown. According to Dobereiner, oil of neroli 
 produces a peculiar acid in contact with platinum-black. Oil of neroli dissolves clearly in 
 1 3 pts. alcohol of specific gravity 0'85, and with turbidity in a larger quantity. Ac- 
 cording to Boullay and Plisson, alcohol of 90 per cent, separates from oil of neroli a 
 solid substance, neroli-camphor, melting at 50 C. ; insoluble in water, sparingly 
 soluble in boiling absolute alcohol; very soluble in ether; it appears to contain 8376 
 per cent. C,15'09 H, and 1-15 ; probably a hydrocarbon when pure. (Grm. xiv. 386 ; 
 Gerh. iii. 639.) 
 
 The leaves of the orange yield a watery infusion characterised by a bitter aromatic 
 taste. 
 
 The following table exhibits the composition of the ash of various parts of tho 
 orange-tree : 
 
CITRUS BERG AMI A CITRUS LIMONUM. 
 
 1003 
 
 Ash of Orange-tree. 
 
 
 ROWNEY and BLOW. 
 
 RICHARDSON. 
 
 
 Root. 
 
 Stem. 
 
 Leaves. 
 
 Fruit. 
 
 Pips. 
 
 Fruit. 
 
 Ash, per cent. 
 
 4-48 
 
 274 
 
 13-7 
 
 3-94 
 
 3-3 
 
 
 
 Potash . 
 
 15-4 
 
 11-7 
 
 16-5 
 
 36-4 
 
 403 
 
 38-7 
 
 Soda . 
 
 4-5 
 
 3-0 
 
 T7 
 
 11-4 
 
 0-9 
 
 7'6 
 
 Lime . . 
 
 49-9 
 
 55-6 
 
 56-4 
 
 24-5 
 
 19-0 
 
 23-0 
 
 Magnesia 
 Ferric oxide 
 
 6-9 
 1-0 
 
 6-3 
 0-6 
 
 5-7 
 0-5 
 
 8-0 
 0-5 
 
 8-7 
 0-8 
 
 6-5 
 
 Sulphuric acid (anhy- 
 drous) 
 
 5-8 
 
 4-6 
 
 4-4 
 
 3-7 
 
 5-1 
 
 2-9 
 
 Silicic acid (anhydrous) 
 
 1-7 
 
 1-2 
 
 4.8 
 
 04 
 
 1-1 
 
 5-2 
 
 Phosphoric acid 
 Chloride of sodium 
 
 13-5 
 1-2 
 
 17-1 
 0-2 
 
 3-3 
 6-6 
 
 11-1 
 
 3-9 
 
 23-2 
 6-8 
 
 14-1 
 
 trace 
 
 Ferric phosphate . 
 
 ~ 
 
 
 ~~~ 
 
 ~~~" 
 
 
 
 17 
 
 CITRUS BERGAMIA. The Bergamot. The rind yields by pressure a volatile oil, 
 C 10 H 18 , which deposits by keeping, a solid camphor called bergaptene, having the 
 composition C 3 H 2 0. (See BERGAMOT, On, OF, p. 580.) 
 
 CITRUS BIGARADIA. The Bigarade or Bitter Orange (Bigaradier of the French, 
 Melangolo of the Italians). The rind of the fruit of this plant yields by pressure a 
 volatile oil, C 10 H 16 , commonly called Oil or Essence of Mandarin (though, the mandarin 
 orange is a variety of Citrus aurantium}. After filtration, it has a pale yellowish 
 colour, but after rectification it is colourless, clear, and mobile. Specific gravity, 0*852 
 at 10 C., 0-8517 at 12. Boiling point 178. It has an agreeable odour, different 
 from that of lemon or orange-oil, and a not unpleasant taste, like that of orange-oil. 
 Optical rotatory power 85'5 to the right. It is insoluble in water, but soluble in 
 10 pts. of alcohol, also in ether and glacial acetic acid, and in all proportions in sul- 
 phide of carbon. It dissolves bromine, iodine, phosphorus, sulphur, oils both fixed 
 and volatile, wax, and resins. With hydrochloric acid it forms a crystalline compound 
 containing C Ie H 16 .2HCl. Cold nitric acid colours it faintly yellow ; hot nitric acid 
 decomposes it, with evolution of nitrous fumes, and the mixture, on addition of water, 
 deposits a nearly solid mass. With alcoholic nitric acid, it forms a crystalline mass, 
 probably a hydrate. It is reddened by cold sulphuric acid, and carbonised when 
 heated therewith. (S. de Luc a, Compt. rend. xlv. 904. Grm. xiv. 304.) 
 
 The Seville bigarade, or Seville orange, is much used for the preparation of bitter 
 tinctures and of candied orange-peel. The bitter aromatic principle is a powerful tonic, 
 and gives its flavour to the liquid called Cim^oa. 
 
 CITRUS LIMETTA. The Lime. The rinds when torn and pressed, or distilled 
 with water, yield an oil which resembles oil of lemon, and when treated with sulphuric 
 acid and chromate of potassium, forms limettic acid, C 1J H 8 8 . (Grm. loc. cit.) 
 
 CITRUS LIMONUM. The Lemon. Eegarded by many writers as a variety of 
 Citrus medica. 
 
 Lemon -juice contains free citric acid, and is used for the preparation of that acid 
 
 sant smell and taste ; to prevent this change, it is often kept in bottles, with a layer of 
 oil on its surface. 
 
 According to Witt (Chem. Soc. Qu. J. vii. 44), lemon-juice contains from 0'2 to 0-5 
 per cent, ash, consisting in 100 pts. of 44-3 per cent, potash, 2'1 soda, 7'6 lime, 3'3 
 magnesia, 12-5 sulphuric anhydride, 197 carbonic anhydride, 7'6 phosphoric anhy- 
 dride, 1-0 ferric phosphate, T2 chlorine, and 0'6 silica. 
 
 Lemon-pips contain in the nucleus, citrate of potassium, a fatty non-drying oil, a 
 tallow-like fat, a bitter principle called limonin, together with other constituents. 
 
 In the ash of lemon-pips, Souchay (J. pr. Chem. xxxviii. 25) found 33'2 per 
 cent, potash, 3*5 soda, 12'6 lime, 8'5 magnesia, 0'2 ferric oxide, 34'1 phosphoric anhy- 
 dride, 3 '2 sulphuric anhydride, 2 - 3 chloride of sodium, and - 3 silica. 
 
1004 CITRUS LIMONUM. 
 
 Oil of lemon. Lemon -peel contains a volatile oil, called Oil of lemon, Oleum citri, 
 which is extracted by pressure or by distillation with water. This oil is composed for 
 the most part of a hydrocarbon isomeric with oil of turpentine, C 10 H 16 , and having the 
 came vapour-density (4'8l 4'87). It is neutral, and has an agreeable odour. Specific 
 gravity in the liquid state, 0'84 0'86 (Zeller ). Boiling point 173 C. (Blanchet 
 and Sell); 176'1 (Brix). It volatilises in the air at ordinary temperatures without 
 leaving a perceptible grease-spot, provided it has not become resinous by oxidation. It 
 deflects the plane of polarisation of light to the right. 
 
 Oil of lemon, obtained as above, is, however, a mixture of two hydrocarbons, having 
 the same composition, but differing in optical rotatory power and in their behaviour 
 with hydrochloric acid. These two hydrocarbons may be separated by distilling the 
 oil in vacuo. The first portions collected at 55 C. have a density of 0-8514 at 15 C., 
 rotatory power = + 56*4, and when saturated with hydrochloric acid gas, yield a solid 
 and a liquid dihydrochlorate. The following portions collected at about 80 C. have a 
 specific gravity of 0'8506 at 15, rotatory power = + 7 2 '5, and are almost wholly 
 transformed by hydrochloric acid into a solid dihydrochlorate ; they likewise contain a 
 sensible amount of oxidised oils. (Berthelot.) 
 
 Oil of lemon dissolves sparingly in water, in 7 '14 pts. alcohol of specific gravity 
 0-8317, in 10 pts. alcohol of specific gravity 0'85, in any quantity of absolute alcohol, 
 and mixes readily with oils both fixed and volatile. It dissolves sulphur and phos- 
 phorus, also resins and other bodies. 
 
 Oil of lemon when exposed to air and light, absorbs oxygen, with formation of ozone, 
 becoming at the same time darker and more viscid, and forming a small quantity of car- 
 bonic acid ; according to Aschoff, the crude, but not the rectified oil, turns acid on expo- 
 sure to the air, forming acetic acid and lemon-camphor. At a red heat, the oil is decom- 
 posed, with formation of tar and charcoal. Chlorine decomposes it ; cotton soaked in the 
 oil and immersed in chlorine gas becomes charred on the surface, but does not take fire. 
 When bromine is covered with a layer of water, the water with oil of lemon, and the 
 whole carefully mixed, the bromine becomes decolorised without explosion, and a bromi- 
 nated oil is formed, 1 pt. of rectified lemon-oil taking up 2'28 pts. and 1 pt. of the crude 
 oil, 2-4 to 2-5 pts. of bromine (G-. Williams, Chem. Gaz. 1853, p. 365). Iodine decom- 
 poses oil of lemon with rise of temperature. Strong nitric acid turns it brown and resi- 
 nises it ; alcoholic nitric acid converts it into a hydrate. With strong sulphuric acid, it 
 assumes a yellowish brown colour, and yields terebene and colophene ; similarly when 
 distilled with phosphoric anhydride. Lemon-oil dropped into a large quantity of oil of 
 vitriol is said to yield sulphoterebic acid (G-erh ardt). Potassium eliminates hydrogen 
 from lemon-oil, slowly at common temperatures, more quickly when heated, acquiring 
 at the same time a brown colour ; after repeated distillation over potassium, however, 
 the oil undergoes no further alteration, and then possesses a finer odour than before. 
 Hydrate of potassium separates from oil of lemon a brown substance, the oil thereby 
 acquiring a stronger and more agreeable odour. 
 
 Oil of lemon is largely used in perfumery ; it should not be dark coloured or viscid 
 or leave a perceptible stain on paper. It is often adulterated with cheaper oils, such 
 as oil of turpentine or oil of lavender, and sometimes with alcohol. The latter adulte- 
 ration may be detected by agitation with water, the pure oil then exhibiting no per- 
 ceptible diminution of volume. The pure oil is also coloured brownish by acid 
 chromate of potassium, whereas if it contains alcohol, it turns greenish. 
 
 The admixture of cheaper oils may generally be detected by the odour. Oil of tur- 
 pentine may also be detected in oil of lemon by its different behaviour to polarised 
 light, especially when heated, the molecular constitution of oil of lemon being much 
 less altered by heat than that of oil of turpentine. The rotatory power of the sus- 
 pected oil is first to be determined at the ordinary temperature, and again after the 
 oil has been heated to 300 C. for an hour or two. If the oil is pure, no change will 
 be perceived, but if oil of turpentine is present, especially the French kind, which is 
 laevo-rotatory, the dextro-rotatory power of the oil will be considerably increased by the 
 heating. 
 
 Hydrate of Lemon-oil is a crystalline substance isomeric with hydrate of tur- 
 pentine-oil, C 10 H 16 .2H 2 0, obtained by mixing 1 pt. of lemon-oil with f pt. alcohol, of 
 specific gravity - 85, and | pt. ordinary nitric acid, and leaving the mixture to itself 
 for some time. (Deville.) 
 
 Hydrochlorates of Lemon-oil. These compounds are formed by saturating the 
 oil with hydrochloric acid gas, also by treating the oil with the aqueous acid. The 
 compound formed in largest quantity is the dihydrochlorate, C 10 H I6 .2HC1, of which 
 there is a solid and a liquid modification, the latter being produced chiefly from the 
 more volatile, the former from the less volatile portion of the oil. (Berthelot, 
 vid. sup.) 
 
CITRUS LUMIA. 1005 
 
 Monohydrochloratc. C 10 H 16 .HC1. This compound is produced by saturating a solu- 
 tion of lemon-oil in acetic acid or alcoholic sulphuric acid, with hydrochloric acid gas, 
 and collecting the few crystals which separate, rarely, however, and only under peculiar 
 circumstances. It appears also to be present in small quantity in the portion of 
 lemon-oil which remains liquid after the separation of the solid dihydrochlorate. The 
 crystals melt at 100 C., and volatilise without decomposition at higher temperatures. 
 
 Dihi/drochlorate. C 10 H I6 .2HC1. The solid modification of this compound is ob- 
 tained by passing dry hydrochloric acid gas to saturation into rectified and dehydrated 
 oil of lemon well cooled, separating the resulting crystals from the mother-liquor, press- 
 ing them repeatedly between paper, washing them with cold alcohol, recrystallising from 
 hot alcohol, drying in the air, afterwards in vacuo or over oil of vitriol, and once more 
 crystallising from ether (Blanchet and Sell). It forms right four-sided prisms or 
 laminse, heavier than water; has an aromatic odour ; is insoluble in water, soluble at 14 C. 
 in 5'88 pts. of alcohol of specific gravity 0'806 ; and separates from the solution, on ad- 
 dition of water, in crystalline laminse. On evaporating the alcoholic solution, partial 
 decomposition takes place. The crystals are also soluble in oils both fixed and vola- 
 tile. The compound is optically inactive, melts at 43 or 44 C., and solidifies cry- 
 stalline on cooling ; it sublimes at 50 C. without decomposition, boils at 142 
 (Cahours), at 162 (Blanchet and Sell), with partial decomposition, hydrochloric 
 acid escaping and an oil passing over, which does not solidify till cooled to 20 C. 
 The crystals burn with difficulty when heated in the air. Chlorine-gas converts the 
 fused compound, with rise of temperature, into a chlorinated compound, C 10 (H 1 'C1 2 ).2HC1, 
 Laurent's hydrochloratr de cMorodtrenhe. 
 
 Dihydrochlorate of lemon-oil is decomposed by silver and mercurous salts in the 
 cold, not by oxide of lead, even when heated. Nitric acid does not act upon it in the 
 cold, but decomposes it when heated, with evolution of nitrous acid. Strong sulphuric 
 acid decomposes it, separating hydrochloric acid. Potassium decomposes it, with sepa- 
 ration of lemon-oil ; if heat be applied, citrene (p. 992) is produced. The same pro- 
 duct is obtained by repeated distillation of the compound with potash or lime, or by 
 the action of those bases at high temperatures. 
 
 The liquid dihydrochlorate, called also hydrochlorate of citrilene and hydrochlorate 
 of citryl, is contained in the mother-liquor of the preceding compound, and may be 
 obtained pure by cooling the mother-liquor to - 10 C. to separate the remaining 
 quantity of the solid compound, and filtering through a mixture of chalk and animal 
 charcoal, to remove free acid and colouring matter. It is a mobile oil, optically inac- 
 tive, soluble in alcohol, and precipitated from the solution by water, with loss of hydro- 
 chloric acid. By treatment with hydrochloric acid gas, it is converted into a crystalline 
 mass, which dissolves in alcohol, but separates therefrom, not in crystals, but in the 
 form of a heavy oil, a small quantity remaining in solution. 
 
 Lemon-camphor or Gitroptene. A solid substance produced from lemon-oil 
 by oxidation. It is formed when the oil is kept for some time in half-filled bottles, 
 partly separating in the solid state, while the rest remains dissolved, and may be sepa- 
 rated by rectifying the oil. It forms colourless volatile crystals, which smell like oil 
 of lemon, have a sharp pungent taste, are neutral, insoluble in cold water, but very 
 soluble in hot water, to which they impart a decided dichroism. It is soluble also in 
 alcohol and ether, the hot saturated solutions solidifying on cooling. The compound 
 melts at 46C. (Mulder), above 100 (Berthelot), boils at a temperature above 100, 
 and distils in oil-drops, which solidify in the crystalline form ; it may also be sublimed. 
 When thrown on red-hot coals, it volatilises without taking fire. It dissolves in sulphuric 
 acid with red colour and peculiar aromatic odour, and water precipitates from the 
 solution a white resinous substance, which is insoluble in water, and does not melt at 
 1 00. Nitric acid dissolves the camphor, with decomposition at common temperatures, 
 but gives off nitrous acid when heated with it. The camphor does not absorb hydro- 
 chloric acid. 
 
 The composition of lemon-camphor is not known with certainty. According to 
 Mulder, it contains 54-8 per cent. C, 9-2 H, and 36'0 ; according to Berthelot, 58-0 C, 
 7-5 H, and 34-5 O. 
 
 The term lemon-camphor is likewise applied to two other compounds, viz. the 
 solid dihydrochlorate of lemon-oil, and the hydrate formed by the action of alcoholic 
 nitric acid on the same oil. 
 
 CITKTTS LUMIA. The Sweet Lemon. This plant, which grows abundantly in 
 Calabria and Sicily, yields a fruit very much like the common lemon. The rind yields 
 by pressure a volatile oil, the greater part of which distils between 180 and 190 C. 
 yielding a colourless limpid liquid. 
 
 The portion boiling at 180 is isomeric with oil of turpentine, &c., and has a density 
 of 0-853 at 18. It possesses a dextro-rotatory power = 34 for the transition-tint. 
 
1006 
 
 CITRYL CLARIFICATION. 
 
 It is slightly soluble in alcoJwl, very soluble in ether and in sulphide of carbon. It is 
 resinised by strong nitric acid, and, like oil of lemon, yields a crystalline hydrate with 
 alcoholic nitric acid. With hydrochloric acid, it forms a liquid and a crystalline com- 
 pound ; the latter, which has a peculiar odour and melts a low temperature, is a dihy- 
 drochlorate, C 10 H I6 .2HC1. (S. de Luca, Compt. rend. li. 258.) 
 
 CITRUS MED ic A. The Citron. (Citradier of the French, Ccdro or Ccdrato of 
 the Italians.) The fruit of this species is usually large, warted and furrowed, with an 
 extremely thick spongy rind and a subacid pulp. 'It is chiefly valued for the fragrance 
 of the rind, from which a delicate sweetmeat is prepared. Two volatile oils used in 
 perfumery are extracted from it, viz. oil of citron and oil of cedra. Both are highly 
 fragrant, almost colourless, and lighter than water ; they are distinguished by their 
 odour, that of oil of cedra partaking of the character of oil of bergamot. The two oils 
 are often confounded by pharmaceutical writers. They appear to be obtained by dis- 
 tillation, as they are free from mucilage. Both of them are hydrocarbons isomeric 
 with oil of turpentine. (Pereira, Matcria Mcdica, 3rd ed. 1853, ii. 2032.) 
 
 CITRYSi. This name is applied to the triatomic radicle, C 6 H 5 4 , of citric acid, 
 &c. ; also by Blanchet and Sell to that portion of lemon-oil which forms a liquid com- 
 pound with hydrochloric acid (p. 1002). 
 
 Chloride of citryl (C 6 H 5 4 )'" Cl 3 , appears to be formed, together with oxychloro- 
 citric acid and chloride of aconityl, when citric acid is heated with pentachloride of 
 phosphorus (p. 997), inasmuch as the mother-liquor which remains after the oxychlo- 
 rocitric acid has crystallised out, yields, on addition of water, both citric and aconitic 
 acids. (PebaL) 
 
 The following is a list of the compounds of citryl described in preceding articles. 
 [C 6 H 5 4 = Ci]. 
 
 Chloride of Citryl . 
 Citric acid . . . 
 
 Citrates, monometallic 
 Citrates, dimetallic . . 
 Citrates, trimetallic 
 Citrate, monomethylic . 
 
 Citrate, dimethylic 
 
 Citrate, trimethylic 
 Citrate, triethylic . 
 
 Citrate, monogly eerie 
 CIVET. 
 
 Ci'"Cl 3 
 
 Ci'" 
 H 2 M 
 
 HM 2 
 
 M' 
 Ci 
 
 s 
 
 
 i") 
 H 3 S 
 H 2 ) 
 
 Ci'") 
 
 (CH 3 ) 2 o 3 
 
 H) 
 
 (C'H 
 
 03 
 
 Citrate, diglyceric . 
 Citromannitan . 
 Dicitromannitan 
 Citramide 
 Phenylcitramide 
 Phenylcitrimide 
 Phenylcitramic acid 
 Diphinylcitramic acid 
 
 cr 
 
 H 3 . 
 
 H 3 ! 
 . Ci'"lo* 
 
 Ci'") 
 
 . HHN 3 
 H 3 J 
 
 Ci'") 
 (C 6 H 5 ) 3 fN 3 
 
 (CTP) 
 . Ci 
 H 3 
 
 . An odoriferous substance obtained from animals of the genus Viverra 
 (Cuv.), viz. the Viverra civetta of North Africa, V. zibetha, found on the continent of 
 Asia, from Arabia to Malabar, and V. Basse of Java. It is contained in a pouch 
 situated between the anus and organs of generation, and is voided by the animals 
 against shrubs or stones. A better quality is, however, obtained by keeping the animals 
 in confinement, and squeezing the pouch at certain intervals. 
 
 Good civet is of a clear yellowish or brownish colour, not fluid, nor hard, but about 
 the consistence of butter or honey, and uniform throughout, of a very strong smell, re- 
 sembling musk or ambergris ; quite offensive when undiluted, but agreeable when only 
 a small portion of civet is mixed with a large quantity of other substances. 
 
CLARIFICATION CLASSIFICATION. 1007 
 
 Civet unites with oils, but not with alcohol. 
 
 Boutron-Charlard states, that in an unexceptionably good civet, semi-fluid, unctuous 
 and yellow, he found free ammonia, stearin, ole'in, mucus, resin, volatile oil, yellow 
 colouring substance, and salts. No benzoic acid could be detected in it. (J. Pharm. 
 1824, p. 537.) 
 
 CLARIFICATION. Clarification is the process of freeing a liquid from hete- 
 rogeneous matter or feculencies ; the term is, however, seldom applied to the mere 
 mechanical process of straining, for which see FILTRATION. Albumin, gelatin, acids, 
 certain salts, lime, blood, and alcohol, serve in many cases to clarify fluids, which 
 cannot be freed from their impurities by simple percolation. Albumin or gelatin, 
 dissolved in a small portion of water, is commonly used for fining vinous liquors, as 
 it inviscates the feculent matter, and gradually subsides with it to the bottom. Al- 
 bumin in the form of white of egg or serum of blood is particularly used for fluids with 
 which it will combine when cold, as syrups ; as it is coagulated by the heat, and then 
 rises in a scum with the dregs. Heat alone clarifies some fluids, as the juices of 
 plants, in which, however, the albumin they contain is probably the agent. A couple 
 of handfuls of marl, thrown into the press, will clarify cider, or water-cider. 
 
 Very finely divided precipitates, which remain for a long time suspended in pure 
 water, may often be made to settle down, by adding a soluble salt, such as sal- 
 ammoniac, to the water. The same addition greatly facilitates the filtering and wash- 
 ing of precipitates, which otherwise stop up the pores of the filter. 
 
 CLASSIFICATION. The object of a classification of chemical substances is 
 the arrangement of them in such a way that the position in the system of each sub- 
 stance may express its own chemical nature and the relation in which it stands to 
 other substances. Hence it is easy to see that a system of classification, which 
 should be perfect, relatively to any given stage in the development of the science, 
 would be an epitome of the whole mass of chemical knowledge existing at the time. 
 Hitherto but slight advances have been made towards establishing a theory of the 
 causes or essential nature of chemical action ; our so-called chemical theories are, 
 for the most part, attempts to express the mutual relations of a greater or lesser num- 
 ber of chemical substances ; in reality, therefore, they are more or less comprehen- 
 sive schemes of classification. A general system of chemical classification ought to 
 embrace the fundamental principles of all such partial systems, so as to show the 
 real nature and relative value of each : it ought, in fact, to be a general expression 
 of these theories in much the same sense that they are general expressions of 
 chemical facts. A discussion of the bases upon which a comprehensive classification 
 is to be founded becomes therefore a discussion of chemical theories in general ; and 
 in this article we shall endeavour to set forth clearly those general results of chemical 
 research, by reference to which the true value of all chemical theories must, in the 
 present state of the science, be tested, and which must for the present, be taken as the 
 foundation for any attempt at chemical classification, rather than to construct a detailed 
 scheme of classification in which each individual substance should find its place. 
 
 A collection of complex objects can always be classified in several different ways, 
 according as this or that quality is regarded as the most important. In the case of 
 chemical substances, two causes are always at work to bring about changes of the 
 point of view from which they are regarded with reference to their classification. In 
 the first place, the number of objects to be classified is continually increasing through 
 the discovery of new substances ; and, in the second place, the finding out of new 
 qualities in the bodies already known, tends continually to modify their apparent 
 relations to each other. Hence it is not surprising that, instead of our being able to 
 trace, in the history of chemistry, the gradual extension of one fundamental scheme of 
 classification, we should find that the principles upon which it has been attempted to 
 classify chemical substances have been gradually, but from time to time almost 
 completely changed as the science has advanced. It is not necessary to consider here 
 what these changes have been ; we have only referred to their occurrence, in order 
 to draw attention to the fact, that the most perfect classification which it is possible 
 even now to give, can of necessity be nothing more than a representation of the results 
 of chemical labour, as they appear viewed from the point which the science has now 
 reached, and that it must hereafter be absorbed in some more general system, if it be 
 not entirely set aside. 
 
 All chemical substances belong to one of two classes : namely, elements or simple 
 bodies, and compound bodies. The chemical definition of an element is a 
 body which cannot be decomposed or shown to contain matter of more than one 
 kind ; compound bodies, on the other hand, are such as are made up of, or can be de- 
 composed into, two or more distinct kinds of matter. For instance, water can be 
 
1008 CLASSIFICATION. 
 
 shown to contain two kinds of matter, called respectively oxygen and hydrogen ; 
 sugar can similarly be proved to be made up of oxygen, hydrogen and carbon ; water 
 and sugar are therefore both of them compound bodies ; but neither oxygen, hydrogen, 
 nor carbon can, by any analytical or breaking-up process, be made to yield anything 
 else than oxygen, hydrogen, or carbon, respectively ; these three bodies are therefore 
 in a chemical sense, elements. It will be seen that the chemical idea of an elementary 
 body does not by any means imply the absolute simplicity of the so-called elements ; 
 it may be that these bodies are compounds which, as yet, have resisted all attempts to 
 decompose them, but which are capable of being decomposed by processes hitherto 
 unknown. Nevertheless, if it should at some future time be shown that all our present 
 elements are in reality compound bodies, the definition of elements as bodies which 
 cannot be chemically decomposed would still hold good, though it would then be ap- 
 plicable to a new set of substances. 
 
 In the further classification of elementary and compound bodies, it is impossible to 
 separate the consideration of one of these classes from that of the other ; for the 
 chemical nature of an elementary body can only be known by the study of the com- 
 binations which it forms ; and the properties of every compound body are determined 
 by those of the elements of which it is composed. 
 
 There are especially two points to be considered in reference to the relation in which 
 the various elements stand to the compounds which they form : first, the atomic 
 proportion in which they combine together ; second, the chemical nature or function 
 of the bodies into whose composition they enter. Considering them first in the former 
 relation, we find that there are a certain number which are distinguished from all the 
 rest by the simplicity of the proportion in which they unite with each other. To this 
 class of elements belong hydrogen (H = 1), chlorine (Cl = 35-5), bromine (Br = 80). 
 iodine (I = 127), potassium (K = 39), sodium (Na = 23), lithium (Li = 7), 
 rubidium (Rb = 85-4), caesium (Cs = 133), silver (Ag = 108).* They combine to- 
 gether usually in the proportion of one atom to one atom (see ATOMIC WEIGHTS), and 
 but few compounds are known which contain more than two of these elements, unless 
 an element of some other class be also present. Trichloride of iodine, IC1 3 f, and the 
 supposed chloride of bromine, BrCP, are perhaps the only exceptions to the former of 
 these rules, and the substances which form an exception to the second are all crystal- 
 lised salts formed by the molecular union of normal binary compounds, such as NaCl 
 and AgCL These bodies cannot be proved to exist, except in the crystallised state, and 
 the chemical properties of their two constituents are not modified to the extent which 
 usually accompanies true chemical combination ; hence it is probable that they are 
 not true chemical individuals, but physical aggregates of entire molecules, analogous to 
 salts containing water of crystallisation. Another property of the elements of this 
 class, closely allied to the first that was mentioned, is that the proportion by volume 
 in which those of them which can be measured in the gaseous state unite, is 1 : 1. 
 
 For reasons that will be lurther dwelt upon in the sequel, the elements of this class 
 are termed monatomic elements ; the remainder are termed polyatomic elements and 
 are divisible into : 
 
 1. Diatomic Elements. These are: oxygen (0 = 16), sulphur (S = 32), selenium 
 (Se = 80), tellurium (Te = 128), magnesium (Mg = 24), zinc (Zn = 65), cadmium, 
 (Cd = 112), mercury (Hg = 200), calcium (Ca = 40), strontium (Sr = 88), barium 
 (Ba = 137), platinum (Pt = 98'5), and perhaps others. The elements of this class 
 combine either two or more together and in very various proportions, e. q. ZnO, ZnS, 
 SO 2 , SO 3 , CaS 5 , Ba 2 SO, BaSO 2 , BaSO 3 , BaSO 4 , BaS 2 3 , BaS 2 0, BaS 4 8 . They combine 
 with the monatomic elements in the proportion of one atom or volume to two, forming 
 compounds of which one molecule occupies twice the volume of the diatomic atom it con- 
 tains, and the same volume as the two monatomic atoms : e. g. H 2 0, C1 2 0, C1HO, 
 KHS, &c. When more than one atom of a diatomic element enters into combination 
 with one or more monatomic elements, the ratio of combination is sometimes much 
 more complex : e. g. H 2 8 , C1 2 S 2 , CPSO, CPSO 2 , KHSO 3 , KHSO 4 , &c.J 
 
 * Fluorine is usually regarded as also belonging to this class, being associated with chlorine, bromine, 
 and iodine; its known analogies to these bodies are not, however, either close or numerous, while its 
 great tendency to unite at the Same time with two different metals, or with hydrogen and a metal, seems 
 to indicate that it ought rather to be placed in the next class of elements (F = 38, hydrofluoric acid = 
 FH^) 
 
 t This is not the only case in which iodine forms a compound of greater complexity than other mem- 
 bers of the same class : for instance, iodic acid forms anhydro-salts, which are without analogues among 
 the compounds of the other monatomic elements. 
 
 | Several elements are here enumerated as diatomic which are usually counted monatomic, and 
 which are taken as such in the body of this work, on account of the inconvenience which would arise 
 from the too great departure from established usage ; partly also because the reasons for supposing some 
 ef them to be diatomic, though strong, cannot be considered quite conclusive. The question whether 
 magnesium, zinc, cadmium, and mercury, and calcium, strontium, and barium, ought to be considered 
 diatomic instead of monatomi'-, resolves it?elf into the question whether the accepted atomic weights of 
 theae element* ought to be doubled. We cannot discuss this question fully here, and must confine our- 
 
CLASSIFICATION. 1009 
 
 2. Triatomic Elements. Nitrogen (N = 14), phosphorus (P = 31), arsenic (As 
 = 75), antimony (Sb = 121), bismuth (Bi = 208) ; boron (B = 11) ; gold (Au = 197) ; 
 probably molybdenum (Mo = 48), vanadium (Vd = 68'5), tungsten (W = 92); and 
 perhaps others. 
 
 These elements do not form many combinations among themselves not containing 
 any element belonging to another class. They combine with the monatomic elements 
 in the proportion of 1 at. to 3, to form such bodies as NH 8 , PH 3 , AsH 3 , SbAg 3 , BiCl 3 , 
 BC1 3 , AuCl 3 , &c. ; 1 at. of some of them can also combine with 5 monatomic atoms, 
 many bodies of the following form being known : NH 4 C1, PH 4 I, PCI 5 , &c. ; but none of 
 these compounds appear to be capable of volatilising without decomposing, so as to re- 
 generate a compound of the class first mentioned, as shown in the following examples : 
 
 NH 4 C1 = NH 3 + HC1 
 
 PCI 5 = PCI 3 + C1CL 
 
 With the diatomic elements and with the diatomic and monatomic elements together, 
 they combine in very various proportions, but always so that the sum of the triatomic 
 atoms, or of the triatomic and monatomic atoms together, when the latter are present, 
 contained in a molecule of the products formed, is an even number. 
 
 3. Tetratomic Elements. Carbon (C = 12), silicon (Si = 28*5), titanium (Ti = 48*5), 
 tin (Sn = 118), tantalum (Ta = 138); probably lead (Pb = 207), and perhaps other 
 elements. 
 
 These elements can combine with the monatomic elements in the proportion of 1 at. 
 to 2 (e. g. SiCl 2 , SnCl 2 ), and with the diatomic elements in the proportion of 1 at. to 1 
 (e.g. CO, SiO, SnO); but the compounds so produced readily combine with 2 mon- 
 atomic atoms, or with 1 diatomic atom, to form such bodies as the following : SiCl 4 , SnCl 4 , 
 COC1 2 , CO 2 , SiO 2 , &c., which appear to represent the normal compounds of the tetra- 
 tomic elements. They also form very many compounds with the triatomic elements, 
 or with these and the monatomic or diatomic elements together. The following are 
 examples of the simplest combinations so produced : 
 C 2 N 2 , CNH, CNHO. 
 
 4. Hexatomic Elements. The following elements are perhaps hexatomic : iron 
 (Fe = 112), aluminium (Al = 54), and other similar bodies. 
 
 selves to the statement of certain facts whose bearing on the point will be understood if the reader has 
 studied the article ATOMIC WEIGHTS. 
 
 at.. Magnesium, Zinc, Cadmium, Mercury. Of these four elements it maybe said, that the evidence in 
 favour of doubling the atomic weights of zinc and mercury is conclusive, while magnesium and cadmium 
 are so obviously members of the same natural family, that it is not possible to double the atomic weights 
 of the former two metals without doubling theirs also. The most important reason for doubling the 
 atomic weights of zinc and mercury are the following : When these metals act upon the iodides of the 
 alcohol-radicles, G5 pts. zinc or 200 pts. mercury combine directly with the quantities represented by the 
 formula; CKPI, C*Wl, CHiiI, &W\, in each case forming a single product, such as Zn"C*Wl, 
 Hg"C 2 H 5 I,Hp 2 "C 3 H 5 I, &c ,as though 65 pts zinc and 200 pts. mercury, represented indivisible quantities, 
 or atoms, of those metals, whereas if these weights represented two atoms, we should expect that the 
 action of 65 pts. zinc or of 200 pts mercury on C a H 5 I would give rise to two distinct products, ethylide 
 and iodide of zinc or of mercury. The combination which actually takes place is analogous to the com- 
 bination of (the diatomic element) oxygen with cyanide of potassium : 
 
 KCy + O == KCyO ; 
 
 if zinc and mercury were monatomic, their action on the hydriodic ethers would probably be analogous 
 to that of (the monatomic element) chlorine on cyanide of potassium : 
 
 KCy + C12 = KC1 + CyCl. 
 
 Again, the reactions represented by the following equations (and the similar reactions which take place 
 with mercury-methyl) all tend to show that a molecule of mercury-ethyl (or mercury-methyl) contains 
 2 at. ethyl (or methyl) : 
 
 Hg(C2H5)(C2H5) + BrBr = Hg^H^Br + C2H.Br (Buckton). 
 
 Hg(C2H6)(C2H5) + CIH = Hg'(C2H s )C1 + C2R5.H (Buckton). 
 
 Hg(C2H t *)(C2H5) + HgClCl = Hg(C2H5)Cl + HgCl(C2H5) (Buckton), 
 
 and it is difficult to understand what can cause the two atoms of alcohol-radicle to remain combined, if it 
 be not that the quantity of mercury with which they are united is one indivisible atom. 
 
 To these chemical arguments may be added that drawn from the determinations which have been made 
 of the vapour-densities of zinc and mercury compounds. All the determinations hitherto made agree 
 with the supposition that the atomic weights of these metals are 65 and 200 respectively, aid not 32'5 and 
 100, as generally admitted ; the specific heats of these metals point also to the same conclusion. 
 
 We may add, finally, that the readiness with which all the four metals under consideration form basic 
 salts is a further indication of their diatomic character. 
 
 /3. Calcium, Strontium, Barium The decomposition of the hydrates of these metals by heat alone, 
 taken in connection with their general close resemblance to the alkalis, may be regarded as evidence 
 o-f their being hydrates of diatomic radicles bearing the same relation to the hydrates of potassium, so- 
 dium, &c., that the bibasic acids (most of which are similarly decomposed by heat) bear to the monobasic 
 acids. Moreover, the non-existence of acid carbonates, sulphates, oxalates, &c., of any of them seems 
 to show that the quantities of metal (twice the qualities usually admitted as representing their atomic 
 weights) contained in their neutral salts with bibasic acids are indivisible. Notwithstanding, however, 
 these and some other indications of a diatomic character, the atomicity of calcium, strontium, and 
 barium must be considered as still more or less open to question. 
 
 VOL. I. 3 T 
 
1010 CLASSIFICATION. 
 
 The existence of this class is not as yet certainly proved ; there is, however, reason 
 to believe that iron, aluminium, and perhaps some of the metals most closely allied 
 to them, are hexatomic, and that their simplest compounds with the monatomic ele- 
 ments contain 6 monatomic atoms (e.g. sesquichloride of iron, Fed 8 ; chloride of alu- 
 minium, Aid 6 ). 
 
 Notwithstanding the exceptions which we have pointed out, the difference in the 
 modes of combination of various elements, which have been indicated as serving for 
 their division into distinct classes, are in the main so marked and so constant as 
 almost to make the conclusion unavoidable that they result from differences in the 
 combining capacity of the elementary atoms themselves ; that in fact the atomic com- 
 bining capacity or atomicity of the various elements is a definite and fixed property 
 comparable to their atomic weight. And, if it be accordingly admitted that an atom 
 of oxygen, or of any other element of the same class, can combine with twice as great 
 a weight of any given element as an atom of hydrogen, or of any other element of its 
 class, that an atom of any element of the nitrogen-class can combine with three times 
 as much, and an atom of any element of the carbon-class with four times as much (that 
 is, if the terms monatomic, diatomic, triatomic, and tetratomic, applied to the various 
 classes into which the elementary bodies have been divided, be admitted to correspond 
 to actual differences in the combining powers of the atoms of the elements), then it 
 is possible to explain, at least to a very great extent, the general differences of com- 
 position which the compounds of these elements show when compared together. 
 
 Upon the classification of the elementary bodies which we have here adopted, we 
 have now to found a classification of their compounds. [In this part of the subject it 
 will often be convenient to use the following general signs for denoting elements of the 
 various classes : 
 
 For monatomic elements, a vertical or horizontal stroke : I or 
 
 For diatomic elements, two such strokes connected at one end by a straight line : 
 
 nc 
 
 For triatomic elements, three strokes connected : 
 
 For tetratomic elements, four strokes connected : |_ J or 
 
 The number of strokes in the sign of each class of elements thus represents their 
 atomicity.] 
 
 The simplest normal combinations which one monatomic, diatomic, triatomic, or 
 tetratomic atom respectively can form, are the following : 
 
 1. Monatomic atom with monatomic, ; example : HC1. 
 
 2. a. Diatomic atom with 2 monatomic, F ~~ ; examples : 6'lf 2 , OHK. 
 b. Diatomic atom with diatomic, F ~] ; example : OHg. 
 
 3. a. Triatomic atom with 3 monatomic, I ; example : NH S , NIPK. 
 
 b. Triatomic atom with 1 monatomic and 1 diatomic, I ; examples : 
 
 sbcio. I ' 
 
 c. Triatomic atom with triatomic, | ] ; example : 
 
 | 1 
 
 i. a. Tetratomic atom with 4 monatomic, ' '; examples: CH 4 , CHC1 8 , 
 
 MM 
 
 b. Tetratomic atom with 2 diatomic, ' ' ; examples : CS 2 , SiO 2 . 
 
 c. Tetratomic atom with 2 monatomic and 1 diatomic, ! ! ; examples : 
 
 CC1 2 6, PbCPO. ' I I I 
 
CLASSIFICATION. 101 1 
 
 d. Tetratomic atom with 1 monatomic and 1 triatomic, | [ ; example : 
 
 CHN. 
 
 e. Tetratomic atom with tetratomic, 
 
 It will be seen that this classification of compounds of the simplest order is equiva- 
 lent to Gerhardt's classification according to types. Compounds of the form 1 are 
 those referred by him to the type HC1 or HH ; those of the form 2a, are those re- 
 ferred to the type H 2 ; those of the form 3a, are those referred to the type H 3 N ; 
 while bodies of the form 4a may be referred to the type H 4 C, subsequently intro- 
 duced (by Odling, Kekule, and others) for the purpose of further extending Gerhardt's 
 system. The sub-forms 2b, ob, 3c, 46, 4c, 4d, 4e, may be regarded as deriving from 
 the primary forms, if we take account of the mult equivalency of the polyatomic elements 
 (see EQUIVALENTS), and consider, for instance, chloroxide of carbon (4c) as representing 
 a body of the form 4 a, in which the diequivalent atom takes the place of 2 mon- 
 atomic atoms, and hydrocyanic acid (4c2) as a body of the same form in which the tri- 
 equivalent atom N takes the place of 3 monatomic atoms. In this way all bodies such 
 as those above mentioned, may be referred to the four types HC1, H 2 0, H 3 N, H J C ; 
 so far, then, the empirical classification of Gerhardt, and that which we have here 
 deduced from the theoretical basis of the definite atomicity of the elements, are 
 identical. 
 
 In order to extend his classification to compounds of a higher degree of complexity, 
 Gerhardt was obliged to assume the existence of an indefinite number of compound 
 radicles : we have now to consider the constitution of such compounds, and shall thus 
 see that the idea of the atomicity of the elements includes, not only the idea of types, 
 but also the idea of compound radicles, ideas which recent chemistry has shown to 
 be correlative, neither of them having any significance except in relation to the other. 
 Comparing now more complex compounds with each other and with the very simple 
 compoiinds of which we have been speaking, we find that, whereas there is no rule as 
 to the number of diatomic or tetratomic atoms which one compound may contain more 
 or less than are contained in another, the difference between the number of monatomic 
 or of triatomic atoms, or of monatomic and triatomic atoms together when both are pre- 
 sent, contained in two well defined and well analysed bodies, is always an even number. 
 But since the compounds constituted according to any of the forms above enumerated 
 always contain an even number of monatomic, or of triatomic, or of monatomic and 
 triatomic atoms together, this amounts to saying that the sum of such atoms contained 
 in any well-defined and well-analysed body is always an even number. This proposition 
 embodies one of the earliest observed regularities in the atomic composition of com- 
 pound bodies (vid. Laurent, Ann. Ch. Phys. [3] xviii. 266), often spoken of as the law 
 of the even number of atoms, and is in strict accordance with the view which regards the 
 combination of the elements as consisting in the mutual saturation of their atomic 
 combining capacities, and might indeed be deduced from it ; for since each unit of 
 combining capacity requires another for its saturation, the number of atoms in every 
 normal compound (or compound in which the atomicity of each element is saturated) 
 must be such that the number representing the sum of their combining capacities is 
 even ; and this can only be the case when it contains an even number of those atoms 
 (monatomic and triatomic atoms) whose atomicity is represented by an odd number. 
 
 The highest number of monatomic atoms that any compound can contain appears 
 to be regulated by the number and nature of the polyatomic atoms which it contains, 
 of a compound contain n polyatomic atoms whose atomicities are respectively 
 A, A', A", &c., the highest number of monatomic atoms that it can contain is A + 
 A' + A" + .... 2(wl) ; but it ma contain any lower number differing from 
 this by a multiple of 2. 
 
 We may illustrate this rule by applying it to the simplest normal compounds of 
 
 atoms of each degree of atomicity. In the case of compounds of the form 1 ( ), 
 
 A + A', &c., = 0, n also =0, thereforej;he formula becomes 2( 1) = 2; in the 
 case of compounds of the form 2a, ([""" ~), A', A", &c., disappear, and n = l, so that 
 the term 2 (n 1) also disappears, and the formula is reduced to A = 2 , in like manner 
 
 in the case of compounds of the form 3a, I | J , the formula becomes A = 3 ; and 
 
 in the case of those of the form 4<z, /j J , it becomes A = 4. All compounds 
 
 belonging to any of these four classes, contain therefore the maximum number of 
 
1012 CLASSIFICATION. 
 
 monatomic atoms. We have previously alluded to some substances in which this 
 maximum appears to be exceeded: namely, first, compounds containing four or 
 sis- monatomic atoms, such as NaAgCl 2 (?) and K 2 AgI 3 ; secondly, compounds 
 containing five monatomic atoms to one triatomic atom, such as NH 4 C1, PGP, &c. 
 There is, however, as already pointed out, reason to believe that all such bodies 
 as these are not strictly speaking chemical individuals, but that they are combina- 
 tions of entire molecules, as such, held together by a force analogous to that which 
 causes certain salts to combine with water of crystallisation. This view may be easily 
 admitted with reference to the first set of exceptional substances, because they cannot be 
 proved to exist, except in the crystalline state: being generally decomposed by solution 
 in a moderate quantity of water, they are often not very constant in the proportions 
 of their ingredients, and the two salts, of which they may be regarded as made up, 
 retain their usual properties without essential alteration. In the case of some of the 
 second class of exceptional bodies, the difficulties in the way of admitting this expla- 
 nation are greater. These bodies are so numerous, and some of them form so readily 
 and are under certain ordinary conditions so stable, that some chemists have been led 
 to regard nitrogen, phosphorus, arsenic and antimony as pentatomic instead of tri- 
 atomic. The chief reason for not adopting this conclusion is that, in all such compounds, 
 two of the monatomic atoms appear to be more loosely combined than the other three, 
 so that even the most stable compounds of this kind, namely the ammonia-salts, are 
 always decomposed to a greater or less extent by the evaporation of their solutions, 
 and not one body of this class appears to be volatile without decomposition (into a com- 
 pound of the form 1, and a compound of the form 3a). But whatever be the real 
 nature of these compounds and of the force which causes their formation, it is certain 
 that they differ in important respects from substances whose composition accords with 
 the atomicity of their components, and that their properties are to a great extent ex- 
 plicable if we regard them as combinations of entire molecules produced independently 
 of the combining capacities of their constituent atoms. (To prevent repetition, we may 
 state here that the same view is applicable to all other compounds of ammonia and 
 similar bodies with acids.) 
 
 But to return and consider how far the composition of other bodies agrees with the for- 
 mula which we have said gives the highest possible number of monatomic atoms that 
 they can contain. It results from the formula that bodies containing two diatomic 
 atoms can contain also two monatomic atoms. Accordingly there exist not only com- 
 pounds of the form P" ^ (referred to above by the number 2i), but also compounds 
 
 of the form [ J, for example, SOCP, 2 H 2 . For bodies containing one triatomic and 
 
 one diatomic atom, the formula gives 3 as the highest number of monatomic atoms that 
 they can contain ; accordingly, in addition to compounds of the form 3A, there exist 
 
 compounds of the form J [, for example, NOC1 3 , POCP. Bodies like those of the 
 
 form 3c, containing two triatomic atoms may, according to the formula, contain at most 
 four monatomic atoms : agreeably with this result, compounds are known of the form 
 
 , for example, NPCP, and of the form , for example, P 2 ! 4 . 
 
 Bodies containing one tetratomic and two diatomic atoms (4i) may by the same rule 
 contain four monatomic atoms : hence we may have bodies of the form J 
 
 example, C0 2 H 2 (formic acid), and bodies of the form ' ; methylic 
 
 glycol, C0 2 H 4 , if known, would be an example of this class. Similarly, bodies containing 
 one tetratomic and one diatomic atom (4<?) may contain four monatomic atoms, forming 
 
 compounds of the form J J, for example, COH 4 (methylic alcohol), CSH* 
 
 (methylic mercaptan) ; bodies containing one tetratomic and one triatomic atom (4d) 
 may contain five monatomic atoms, forming compounds of the form [ 
 
CLASSIFICATION. 1013 
 
 for example, CNH S (methylamine) ; and bodies containing two tetratomic atoms 
 may contain two, four, or six monatomic atoms giving compounds of the form 
 
 , example, C 2 H 2 (acetylene) ;j 'example, C 2 H< (ethy- 
 
 lene) ; or example, C 2 H 6 (hydride of ethyl) 
 
 The question now arises, how far is this law of the combination of the different 
 elements in accordance with the idea of their having each a definite and constant 
 atomicity ? A little consideration will show that it is a necessary consequence of that 
 supposition. The total combining capacity of any number of atoms is evidently the 
 sum of their several combining capacities, and if these latter be denoted by A, A', A", 
 &c., will be expressed by A + A' + A" + . . . . ; but if the atoms be combined to- 
 gether, their total combining capacity will not be so great as in the free state, it will 
 have been more or less saturated by the combination which has taken place among 
 them. The atomicity of as many of them as are monatomic, will have been entirely 
 saturated by the combination, but the atomicity of such as are polyatomic may be only 
 partially saturated ; and it will be saturated to the smallest possible extent if, of all 
 but two of them, two units of combining capacity be saturated each by one unit of a 
 different atom, and if one unit of each of the remaining two atoms be saturated. This 
 mode of combination is shown by the following diagram, representing 2 tetratomic 
 atoms, 1 triatomic atom, and 2 diatomic atoms combined in the way described : 
 
 U i i i i U 
 
 Since the free atomicity (if we may use the expression) of all but two atoms is thus 
 diminished by two units, and the free atomicity of each of the remaining two atoms is 
 diminished by one unit, the total remaining free atomicity of the group is equal to the 
 total atomicity of the uncombined atoms (or A + A' + A" + . . . .), diminished by 
 (2(n - 2) + 2), 
 
 that is : A + A' + A" + 2(n - 2) - 2 = A 4 A' + A" + 2(n- 1), 
 
 which is the precise expression, some of whose consequences we have above discussed. 
 It is evident that no combination can take place without the saturation of at least 
 two units of atomieity, one belonging to each of the combining atoms. Hence, when 
 a monatomic atom combines with any other atom, or group of atoms, the atomicity of 
 the product must be one less than that of such atom or group of atoms : for the mon- 
 atomic atom brings to the compound that is formed only one unit of atomicity, whereas 
 two units are saturated by the combination. Therefore, as we have seen, the number 
 of monatomic atoms with which any atom or group of atoms can combine, is always 
 limited. For similar reasons the total atomicity of any atom or group is the same as 
 that of its compound with a diatomic atom. From this follow the several consequences : 
 first, there is a priori no assignable limit to the number of diatomic atoms with which 
 a given atom or group may combine ; secondly, compounds which do not contain 
 atoms whose atomicity is represented by a higher number than 2, never contain more 
 than two monatomic atoms ; e. g. water, H 2 0, and sulphydric acid, H S, each contain 
 two monatomic and one diatomic atom, while pentathionic acid, H 2 S 5 6 , contains 
 eleven diatomic, but still only two monatomic atoms ; thirdly, compounds containing 
 the maximum number of monatomic atoms do not become able to combine with a 
 greater number through union with any number of diatomic atoms ; e. g. hydride of 
 hexylene, C 6 H 14 , contains the maximum of monatomic atoms, but mannite, C 6 H 14 6 , 
 differing from it by containing s additional, is not capable of further combination 
 with monatomic atoms. When a triatomic atom enters into combination, it brings to 
 the compound three units of atomicity, and two units are saturated by the combina- 
 tion, so that the entire atomicity of the product exceeds that of the original substance 
 by one. Hence, when a triatomic element, as nitrogen, combines with a group already 
 containing the maximum of monatomic atoms, the group becomes able to take up an 
 additional monatomic atom ; accordingly, we have many compounds which differ by 
 NH, or a multiple of it, e.g., C 2 H 8 (hydride of ethyl), C 2 H 7 N (ethylamine), C 2 H 8 N 3 
 (ethylene-diamine) ; C 2 H 4 (aldehyde), C 8 H 5 NO (acetamide) ; C 2 H 4 2 (acetic acid), 
 C 2 H 5 N0 8 (glycocine). When a tetratomic atom is added to a group, the total atomicity 
 of the product in like manner exceeds that of the original substance by 2. Hence the 
 possibility of the many series of compounds of which the terms differ by CH 2 or by a 
 multiple thereot 
 
1014 CLASSIFICATION. 
 
 It will be understood that the foregoing remarks touching the combining capacity 
 of various atomic groupings, and the way in which it is affected by the addition of 
 atoms of various kinds, have reference only to the highest number of monatomic atoms' 
 that is ever found in combination with a given number of polyatomic atoms ; and that 
 it is by no means intended to imply that all compounds contain, or even show any 
 great tendency to combine with, the whole number of monatomic atoms which the 
 rules above given indicate as the maximum in each case. Several compounds not 
 containing the maximum of monatomic atoms have already been incidentally referred 
 to ; but it is necessary that the constitution of such compounds should be somewhat 
 more specially discussed in relation to the theory of the definite combining capacity 
 of the elementary atoms. 
 
 According to this theory, there are four different ways in which it is possible for 
 two tetratomic atoms, for instance, two atoms of carbon, to combine. Two such atoms 
 may mutually saturate, either the whole, three fourths, one half, or one fourth of each 
 other's combining capacity, as expressed by the following diagrams : 
 
 Each atom Each atom Each atom Each atom 
 
 completelysaturated. f saturated. saturated. saturated. 
 
 The first diagram probably represents some variety of free carbon ; the second, third, 
 and fourth, the manner in which the two carbon-atoms are combined in acetylene, 
 C 2 H 2 , ethylene, C 2 H 4 , and hydride of ethyl, C 2 H 6 , respectively. In the last of 'these 
 bodies, one unit only of the combining capacity of each carbon-atom is saturated by 
 the other, leaving three units of affinity belonging to each free for combination with 
 hydrogen ; and it is plain that two atoms of carbon can only combine with a larger 
 number of hydrogen, or other monatomic atoms, than are contained in this compound, 
 when they are entirely uncombined with each other. In ethylene and acetylene, on 
 the other hand, the two atoms of carbon are so combined that, if we may so speak, 
 they can combine with an additional number of monatomic atoms by loosening, with- 
 out entirely giving up, their hold upon each other. And in all compounds in which 
 the proportion of monatomic to polyatomic atoms is below the maximum indicated by 
 the formula given higher up, we must, unless we suppose the atomicity of the elements 
 to be variable (in which case the word atomicity ceases to have any special meaning), 
 suppose that a greater or lesser number of the polyatomic atoms are combined in a simi- 
 lar way. But, in the great majority of such cases, the composition alone of a compound 
 does not enable us to decide as to how many of its polyatomic atoms are in this kind 
 of more intimate union with each other. For example, allylene, C 3 H 4 , homologous with 
 acetylene, might, so far as its mere composition is concerned, be constituted either 
 
 ever, would be somewhat different in the two cases. It would not be possible to com- 
 bine a compound constituted in the first manner with two atoms of hydrogen, without 
 transforming it into propylene, C 8 H 6 , or an isomeric body ; but it would doubtless be 
 possible, under appropriate conditions, to cause a body constituted in the second 
 manner to split up, by the addition of two atoms of hydrogen, into marsh-gas, CH 4 
 
 or | j, and acetylene, C 2 H 2 , or ' 
 
 In the preceding part of this article, we have tried to show that those of the elements 
 which have been sufficiently studied may be divided into distinct classes, according to 
 the manner in which they enter into combination, and further, that each element pos- 
 sesses a certain definite atomic combining capacity, which regulates the formation of 
 its most complex as well as of its simplest compounds. By the application of this 
 principle of the definite atomicity of the elements, it would be easy to construct tables 
 showing all the possible combinations of each element ; all compounds whose constitu- 
 tion was sufficiently understood, might then be classified by inserting them in their 
 places in these tables. But since the place of any compound would be determined, 
 not only by its composition, but also by the mode or order of combination of its atoms, 
 a point concerning which we have, in most cases, no definite knowledge, such a 
 system of classification would not be widely applicable in the present state of che- 
 mistry. Our acquaintance with the great majority of the more complex compounds con- 
 sists in the knowledge of transformations, by which only a small number of their atoms 
 are affected. It has, therefore, been found convenient, for the purposes of classification 
 
CLASSIFICATION. 1015 
 
 to regard such compounds as consisting of two parts, namely, the atom r atoms which 
 take part in their known transformations, and a residue, or nucleus, or radicle, which 
 is unaffected by these transformations, and appears as a constant constituent in all 
 the products to which they give rise. By aid of this convention, the classification 
 founded upon the atomicity of their elements, which, as we have seen, is applicable to 
 the more simple compounds, may be extended so as to comprehend all tolerably well 
 known substances. The radicles, whose existence this view supposes, may be of any 
 degree of complexity ; their nature and their relation to the compounds in which they are 
 contained will be most easily understood by considering a few of the simplest of them. 
 Hydrochloric acid, HC1, water, H 2 0, ammonia, H 3 N, and marsh-gas, H*C, have al- 
 ready been shown to be compounds, each of which may be taken as the representative 
 of a whole class of bodies. If we imagine 1 atom of hydrogen to be removed from each 
 of these substances, it is plain that the residues Cl, HO, H' 2 N, H 3 C, will each be able 
 to combine with an atom of hydrogen to reproduce the original compounds, or with 
 some other monatomic atom, such as chlorine or potassium, to form such bodies as : 
 
 KC1, C1C1; KHO, C1HO ; KH 2 N; KH 3 C, C1H 3 C ; &c. 
 
 It is plain also, since 1 at. of a diatomic element is equivalent in combining capacity 
 to 2 monatomic atoms, that 1 at. of oxygen, sulphur, &c., will combine with 2 at. of 
 each of these residues, or with two different residues at once, or with 1 at. of a residue 
 and with 1 at. of a monatomie element, forming such compounds as the following : 
 
 n (Cl n <H 3 C n (H 3 C n <H 8 C MH 3 C 
 
 ^ ^ rn '-' i TTsrt i V s Trsns* , V 
 
 For similar reasons, it is evident that 1 at. of a triatomic element will combine with 
 3 at. of such residues, or with 2 at. of residue and 1 at. of a monatomic element, or 
 with 1 at. of residue and 2 monatomic elementary atoms, e. g. : 
 
 [Cl (H 3 C (H S C (H 3 C (H 3 C 
 
 3 C, NtoC 2 , N^H 3 C, ISNH , &c. 
 H S C (HC 5 t (H (H 
 
 In like manner, 1 at. of a tetratomic element will combine with 4 at. of residue, or 
 with 4 at. partly of residue and partly elementary, e. g. : 
 
 (HO 
 
 (Cl 
 
 N]CI, 
 
 (Cl 
 
 c 
 
 H 3 C 
 
 &c. 
 
 H 
 IH 
 
 From all this it follows that these residues or radicles follow the same laws of com- 
 bination with the elementary bodies of different classes as do the monatomic elements 
 themselves. Further, they combine also with one another according to the same laws 
 as are followed by elementary monatomic atoms ; that is, they combine together in the 
 proportion of 1 at. to 1 at, e. g. : 
 
 Cl + H 3 C = C1H 8 C 
 
 Chloride of methyl. 
 
 HO -- H 3 C = OH 4 C 
 
 Methylic alcohol. 
 
 H 2 N + H 3 C = NH 5 C 
 
 Methylamine. 
 
 H 3 C + H 3 C H 6 C 2 
 
 Free methyl. 
 
 But, just as there are not only monatomic but also polyatomic elements, so there 
 are polyatomic as well as monatomic radicles. If we suppose H 2 to be withdrawn 
 from each of the compounds H 2 0, H 3 N, H 4 C, it is evident that the residues 0, 
 HN, H 2 C, will have the properties of diatomic radicles, the compound radicles HN and 
 H 2 C being similar in their combining capacity to the simple radicle O, just as the 
 compound radicles HO, H 2 N, and H 3 C, resemble the simple radicle Cl in their com- 
 bining capacity. After the detailed illustration of the properties of the monatomic 
 radicles given above, it is not necessary to dwell upon the characters of the diatomic 
 radicles, since what has been said of the former applies, mutatis mutandis, to the latter. 
 In like manner, the abstraction of H 3 from H 3 N and H 4 C gives the triatomic radicles 
 N and HC ; and the withdrawal of H 4 from any normal compound leaves a tetratomic 
 radicle analogous in properties to the simple radicle C, which results from the with- 
 drawal of H 4 from H 4 C. 
 
 H'C2 = H6C2 - H : it is a residue or radicle comparable to H 3 C. 
 f H'C 5 = HC S - H. 
 
1016 
 
 CLASSIFICATION. 
 
 Although, in considering the properties and combinations of these or of other com- 
 pound radicles, we may confine our view to their analogies with the elementary bodies 
 and regard their atomicity as an ultimate property, which, like the atomicity of the 
 elements, is not to be explained, it is easy to see that the atomicity of the radicles of 
 which we have spoken, is the direct result of their composition and the atomicity of their 
 component atoms. It only requires to be put into words to be at once evident that, if 
 one, two, three, or more monatomic atoms be removed from any normal compound what- 
 ever, the remainder will be a substance possessing one, two, three, or more units of 
 atomicity free for combining with other bodies, and therefore, as to its power of com- 
 bination, exactly analogous to an atom of an element whose atomicity is represented 
 by one, two, three, or a higher number. Hence the derivation of any compound 
 radicle determines its atomicity. The maximum atomicity of a radicle may also be 
 always deduced from its composition by means of the formula A + A' + A" + .... 
 2(n 1), in which A, A', A", &a., indicate the atomicities of the elementary atoms, 
 monatomic as well as polyatomic, of which the radicle is composed, and TO the number 
 of atoms it contains. From this formula it follows that a compound radicle can never 
 consist of monatomic atoms only; that radicles containing only diatomic atoms are 
 always diatomic ; and that the atomicity of radicles containing only tetratomic, or tetra- 
 tomic and diatomic atoms, is always represented by 2, 4, or some other even number. 
 It follows also from the same formula, and from what has been previously said as to the 
 composition of complex compounds in general, that, starting from the shnple radicles 
 already described, there may exist series of radicles of the same atomicity in which 
 
 the common difference is e.g. 0; or 
 
 , e.g. HN; or 
 
 
 , e.g. CH 2 . 
 
 For example : 
 Common difference, V 
 
 Cl 
 
 CIO 
 
 CIO 2 
 
 CIO 3 
 
 CIO* 
 
 O 
 
 SO 
 SO 2 
 
 Common difference, 
 
 HO H 
 
 PH 2 (in hypophos- NH 2 
 phites) 
 
 Common 
 difference, I I 
 
 CH 3 CH 2 CH 
 
 C 2 H 5 C 2 H 4 C'H 8 
 
 Cm 7 C*H 6 C 3 H 5 
 
 &c. &c. &c. 
 
 From these, considered as primary radicles, so-called derived or conjugate radicles may 
 arise by equivalent substitution ; for instance, by substitution of Cl, Br, or I, for H ; of 
 O or S for H 2 ; of S for ; of N for H 3 , or for HO 2 , &c. ; or of NO 2 or NH 2 for H ; or of 
 SO 2 or CO for H 2 , or generally of any radicle for its equivalent. Again, still other 
 radicles exist differing from these by containing some multiple of H 8 (or its equiva- 
 lent) less than they do, but possessing the same atomicity ; for example, we have 
 ethyl, C 2 H 5 , and vinyl, C 2 H 3 ; trityl, C 3 H 7 , and allyl, C 3 H 5 ; propionyl, C 3 H 5 0, and 
 acryl, C 3 H 3 ; hexyl, C G H 13 , and phenyl, C 6 H 5 ; all of them monatomic radicles. 
 
 Hence it follows that triatomic radicles may often be isomeric with monatomic 
 radicles; for example, acctyl (Berzelius) C 2 H 3 , triatomic, with #my/,C 2 H 3 , monatomic ; 
 gtyceri/l, C 3 H 5 , triatomic, with allyl, C 3 H 5 , monatomic ; in like manner, tetratomic 
 and diatomic radicles may be isomeric with each other; for example, tartryl, C 4 H 2 2 , 
 
 tetratomic (tartaric acid = ( G *^) lr I Q 4 ), with fumaryl, C 4 H 2 2 , diatomic (fumaric 
 
 acid = ^ ' TTg [ O 2 ). In such cases, we must suppose that the carbon (or other 
 
 polyatomic atoms) of the radicles which contain a smaller proportion of hydrogen, or 
 which have a lower atomicity, are more intimately combined with each other than they 
 are in those which, having the same atomicity, contain a larger proportion of hydrogen, 
 or with the same composition have a higher atomicity. 
 
 We have hitherto spoken only of the composition and atomicity of compound radicles ; 
 it remains to explain a little more fully the grounds upon which their existence in 
 various compounds is assumed, and what that assumption is intended to imply. It 
 has been said that compound radicles are groups of elements which are contained in 
 a greater or lesser number of bodies, and are unaltered in the reactions by which one of 
 these is transformed into another. For instance, the bodies of the following series : 
 CWO ....... Oil of bitter-almonds, 
 
 C 7 H 5 C10 ....... Chloride of benzoyl, 
 
 C 7 H 6 2 ....... Benzoicacid, 
 
 C 7 H 7 ON ....... Benzamide, 
 
 CH 5 ON ...... , Cyanide of benzoyl, 
 
CLASSIFICATION. 1017 
 
 contain the group C 7 H S (benzoyl) as a common constituent which remains unchanged 
 when they are transformed one into another. Now the reactions by which these trans- 
 formations are effected are essentially quite similar to those by which the following 
 bodies are changed one into another. 
 
 KH (?) Hydride of potassium. 
 
 KC1 Chloride of potassium. 
 
 KHO Hydrate of potassium. 
 
 KH 2 N Potassamine. 
 
 KCN Cyanide of potassium. 
 
 This analogy is hidden if the formulae of the bodies of the former series are written 
 as above ; but if they are written as containing the compound radicle benzoyl, C 7 H 6 0, 
 the analogy becomes at once apparent : 
 
 (C 7 H 5 0)H . Hydride of benzoyl, or oil of bitter-almonds. 
 
 (C 7 H S 0)C1 
 (C 7 H 5 0)HO 
 (C 7 H 5 0)H 2 N 
 (C 7 H 5 0)CN 
 
 Chloride of benzoyl. 
 
 Hydrate of benzoyl, or benzoic acid. 
 
 Benzamide. 
 
 Cyanide of benzoyL 
 
 These latter formulae express that the bodies represented by them are functionally 
 analogous to compounds of the monatomic elements, and that they respectively possess 
 the general properties of those classes of bodies of which HC1, H 2 0, H 3 N, &c., are the 
 typical representatives. 
 
 The precise nature of the radicle which any substance is represented as containing 
 will naturally vary according as it is desired to express the relations of the sub- 
 stance in question to this or that series of other bodies, or its capability of undergoing 
 this or that series of transformations. If, for example, we wish to express the relation 
 in which acetic acid stands to aldehyde, chloride of acetyl, acetamide, &c., we shall 
 do so most simply by representing it as the hydrate of the compound radicle acetyl, 
 
 C 2 H 3 0, thus, C H g 1 0. But if it be desired to express also that, by distillation with 
 
 excess of alkali, by electrolysis, or by distillation with arsenious acid, acetic acid is 
 resolved into a compound of the methyl series and a compound of the carbonic series, 
 and that it can be formed from sodium-methyl and carbonic anhydride, or from 
 cyanide of methyl by the action of alkali, this must be expressed by representing the 
 radicle C 2 H 3 as composed of the simpler radicles CH 3 and CO ; and if we fvuther 
 wish to express the analogy of acetic acid to formic acid, we must write acetyl thus, 
 C(CH 3 )0, or as formyl, CHO, in which hydrogen is replaced by methyl : the whole 
 
 formula of acetic acid then becomes * -rV [ 0. Similarly, in order to express the 
 
 H 
 
 relations of acetic acid to still other seta of compounds, we are obliged to represent it 
 as containing radicles of continually simpler composition, until finally we come to 
 represent it as built up from elementary atoms ; for instance, thus : 
 
 c no 
 
 rm n n 
 
 ill 
 
 H li ii o H 
 
 Hence the idea of a compound radicle is seen to be entirely relative, the same body 
 from one point of view appearing to contain one compound radicle, and from another 
 point of view appearing to contain a different one. A comparison of the definition 
 of an elementary body, given near the begining of this article, with that of a compound 
 radicle, shows that compound radicles bear the same relation to certain more or less limited 
 sets of chemical processes that the elements bear to all the chemical processes known. 
 The application of the principles which we have been discussing, to the classification 
 of chemical compounds generally, is illustrated by the following table, which is a modi- 
 fication and extension of that given by Gerhardt ( Traitl, iv. 612, 613), and reproduced 
 in Graham's Elements of Chemistry (2nd edit. ii. 528, 529). By referring to the de- 
 tailed comm ntaries by which Gerhardt's table of classification is followed in the 
 places referred to, the reader will be able f o understand fully the meaning of this table 
 without requiring further explanation in this place. 
 
1018 
 
 CLASSIFICATION. 
 
 Classification 
 
 Compounds comparable to Hydrochloric Acid, 
 HCL 
 
 Compounds comparable 
 
 Containing mon- 
 atomic radicles 
 (Chlorides, Hy- 
 drides, &c.) 
 
 Containing di- 
 atomic radicles 
 
 (Bichlorides, 
 Dihydrides.&c.) 
 
 Containing 
 triatomic ra- 
 dicles (Tri- 
 chlorides, 
 Trihy- 
 drides, &c.) 
 
 Containing 
 tetratomic 
 radicles 
 Tetrachlo- 
 rides, 
 Tetrahy- 
 drides, &c.) 
 
 Containing mon- 
 atomic radicles 
 (Oxides, &c.) 
 
 Containing di- 
 atomic radicles 
 (Dioxides, &c.) 
 
 Basic chlorides, hydrides, cyanides, &,c. 
 
 Basic oxides, sulphides, 
 
 Haloid salts. 
 
 
 (chloride of po- 
 tassium, KC1) 
 
 (chloride of 
 mercury, 
 HgCl2). 
 
 (chloride of I (chloride 
 antimony, of tin, 
 SbU3). SnCl 4 ). 
 
 1. Primary, or hy- 
 drates (hydrate 
 of potassium, 
 
 1. Primary (hy- 
 drate of calcium, 
 CaH2Q2). 
 
 
 
 I 
 
 KHO). 
 
 
 Metallic hydrides (hydride of copper, $c.) 
 
 
 
 
 
 
 
 2. Secondary, or 
 
 2. Secondary (soda- 
 
 
 - 
 
 
 
 anhydrides (ox- 
 
 lime, Na'Ca02). 
 
 
 
 
 
 ide of potas- 
 
 
 
 
 
 
 sium, K.2Q). 
 
 
 Metals proper and alloys. 
 
 
 
 
 
 (potassium, KK.) 
 
 (silver-amal- 
 
 
 
 
 
 
 gam.) 
 
 
 
 
 
 Alcoholic chlorides, hydrides, <Scc. 
 
 Alcoholic oxides, 
 
 Halogen ethers. 
 (chloride of ethyl,! (chloride of 
 C 2 H*C1). ethylene, 
 
 | C2H4C12). 
 
 (trichlorhy- 
 drine, 
 
 C3H5CP) 
 
 
 1. Primary (com- 
 mon alcohol, 
 
 1. Primary (glycol, 
 (C 2 H 4 )H2O 2 ). 
 
 Metallic compounds of alcohol-radicles. 
 
 
 
 
 (potassium-ethyl, 
 KC2H*). 
 
 (zinc-ethyl, 
 Zn(C 2 H s ) 2 ). 
 
 (bismethyl, 
 
 (plumb- 
 ethyl, 
 Pb(C2H3)) 
 
 2. Secondary (com- 
 mon ether, 
 
 2. Secondary. 
 
 
 
 
 
 Intermediate oxides, 
 
 Monatomic oxy- Diatomic oxysalts 
 
 
 
 
 
 salts and ethers 
 
 and ethers (sul- 
 
 
 
 
 
 (chlorate of potas- 
 sium, (CIO2)KO; 
 
 phate of potassium, 
 (S02)K202 ; sul- 
 
 
 
 
 
 acetate of ethyl, 
 (C 2 H 3 O)(C 2 H 5 )O). 
 
 phate of ethyl, 
 (SO2)(C 2 H 5 )2O 2 ) 
 
 Acid chlorides, hydrides, &.c. 
 
 Acid oxides, 
 
 Ad-chlorides. 
 
 
 (chloride of 
 acetyl, 
 (C2R30)C1). 
 
 (chloride of 
 succinyl, 
 
 (chloride of 
 
 
 1 . Primary (acetic 
 acW,(C2H30)HO). 
 
 1. Primary (sulphuric 
 acid, (S02)H202). 
 
 Aldehydes, acetones, Sfc. 
 
 
 
 
 
 (acetic aldehyde, 
 (C 2 H 3 0)H; 
 
 
 
 
 2. Secondary (ace- 
 tic anhydride, 
 
 2. Secondary (succi- 
 nate of ethylene, 
 
 acetone, 
 
 
 
 
 (C 2 H3Q)2O). 
 
 
CLASSIFICATION. 
 
 1019 
 
 according to Types. 
 
 to -Water, H 2 0. 
 
 Compounds comparable to Ammonia, H 9 N. 
 
 Containing tri- 
 atomic radicles 
 (Trioxides, &c.) 
 
 Containing te- 
 tratomic radicles 
 (Tetroxides, &c.) 
 
 Containing mon- 
 atomic radicles 
 (Amines and Amides). 
 
 Containing di- 
 atomic radicles 
 (Diamines and 
 Diamides). 
 
 Containing triatomic 
 radicles (Triamines 
 and Triamides). 
 
 Containing 
 tetratomic 
 radicles 
 (Tetramines 
 and 're- 
 tram ides). 
 
 selenides, &c. 
 
 Basic nitrides, phosphides, arsenides, &c. 
 
 1. Primary (hy- 
 drate of 
 bismuth, 
 
 1. Primary. 
 
 . Primary (amide of 
 potassium, KH 2 N). 
 
 1. Primary 
 (zincamide, 
 
 1. Primary. 
 
 1. Primary. 
 
 2. Secondary '(ox- 
 ide of bis- 
 muth, B12Q3). 
 
 2. Secondary. 
 
 2. Secondary. 
 
 2. Secondary. 
 
 2. Secondary. 
 
 2, Second- 
 ary. 
 
 
 
 3. Tertiary (nitride of 
 potassium, K 3 N). 
 
 3. Tertiary (ni- 
 tride of zinc, 
 
 3. Tertiary. 
 
 3. Tertiary. 
 
 sulphides, &,c. 
 
 Alcoholic nitrides, phosphides, <Stc. 
 
 I. Primary 
 
 (glycerin, 
 
 1. Primary. 
 
 1. Primary ( ethyl - 
 amine, (C' 2 H 5 )H-N). 
 
 1 . Primary (ethyl- 
 enediamine, 
 
 1. Primary. 
 
 1. Primary. 
 
 2. Secondary (ox- 
 ide of glyceryl, 
 
 2. Secondary. 
 
 2. Secondary (diethyl- 
 amine, (C^H^HN), 
 
 2. Secondary (di- 
 ethylenediamine, 
 
 2. Secondary. 
 
 2. Second- 
 ary. 
 
 
 
 3. Tertiary (triethvl- 
 amine, (C-H') 3 N). 
 
 3. Tertiary (tri- 
 ethylenediamine, 
 
 3. Tertiary. 
 
 3. Tertiary. 
 
 sulphides, &.c. 
 
 Intermediate nitrides, phosphides, &c. 
 
 Triatomic oxy- 
 salts and ethers 
 (phosphate of 
 bismuth, 
 iPOjBiO'; 
 phosphate 
 of ethyl, 
 (PO)(C2H 5 ) 3 O 3 ). 
 
 Tetratomic oxy- 
 saltsand ethers 
 (orthosilicates, 
 orthosilicate 
 of ethyl, 
 
 Monalkalamides 
 (ethyl-acetamide, 
 
 silver-acetamide, 
 Ag(C*H 3 0)HN). 
 
 Dialkalamides, 
 (oxanilide, 
 ' C2O 2 )(C 6 H 5 ) 2 N 2 ). 
 
 Trialkalamides 
 (citranilide. 
 
 Tetralkal- 
 amides. 
 
 sulphides, &.C. 
 
 Acid nitrides, phosphides, &.c. 
 
 I. Primary ( phos- 
 phoric acid, 
 (P0)il 3 03). 
 
 1. Primary (tar- 
 taric acid, 
 (C<H2O 2 )H'O 4 ) 
 
 1. Primary (acetamide 
 (C2H 3 O)H 2 N). 
 
 1. Primary 
 (oxamide, 
 
 1. Primary (phog 
 photriamide, 
 (PO)H 6 N2). 
 
 I. Primary. 
 
 2. Secondary 
 (phpspheric 
 
 anhydride, 
 
 "i. 'Secondary- 
 
 2. Secondary (diaceta- 
 
 2. Secondary. 
 
 2. Secondary. 
 
 2. Second- 
 ary. 
 
 
 
 3. Tertiary (dlbenznyl- 
 sul|)ho-phenylamide, 
 
 3. Tertiary. 
 (trisuccinamide, 
 
 3. Tertiaty. 
 
 3. Tertiary. 
 
1020 
 
 CLASSIFICATION. 
 
 The groups into which chemical substances are here divided, may be considered as 
 representing the principal varieties, but they are far from including all chemical com- 
 pounds. By means of polyatomic radicles, molecules may be built up of much greater 
 complexity than any shown in this table. There appears to be no assignable limit to 
 the number of such compounds or to the degree of complexity which they may reach. 
 Without discussing these bodies at length, we shall be able, by a few examples, to illus- 
 trate their nature and their relation to more simple substances. One of the most re- 
 markable series of bodies of the kind to which we refer, are the polyethylenic alcohols 
 of Louren90 and Wurtz. These chemists have shown that glycol, (C 2 H*)H 2 2 , is able 
 to fix upon itself the elements of several molecules of oxide of ethylene, so as to give 
 the following series of products : 
 
 (C 2 H 4 ) 2 H 2 8 
 
 Diethylenic 
 
 alcohol. 
 
 (C 2 H 4 ) S H 2 4 
 
 Triethylenic 
 
 alcohol. 
 
 (C 2 H 4 ) 4 H 2 5 
 
 Tetrethylenic 
 alcohol. 
 
 (C 2 H 4 ) s H 2 O a 
 
 Veil tot hylenic 
 alcohol. 
 
 (C 2 H 4 ) 6 H 2 7 
 
 Hexethylenic 
 alcohol. 
 
 The principal transformations of glycol (monethylenic alcohol) itself are most conve- 
 niently expressed by representing it as containing the diatomic radicle ethylene, C 2 H 4 . 
 With this radicle we must suppose the 2 at. of oxygen contained in glycol to be com- 
 bined in such a manner that half the combining capacity of each is saturated by half the 
 combining capacity of the radicle, the other half of the combining capacity of each atom 
 of oxygen being saturated by an atom of hydrogen. This view of the constitution of 
 
 H [O 
 
 glycol is expressed by the following formula, (C 2 H 4 )" j . Thus regarded, glycol may 
 
 H | 
 
 be compared to water by representing it as two molecules of water in which H 2 is re- 
 placed by (C 2 H 4 )". The polyethylenic alcohols then become comparable to glycol if 
 viewed as 3, 4, 5, &c., molecules of water in which respectively (C 2 H 4 ) 2 , (C 2 H 4 ) 3 , 
 (C 2 H 4 ) 4 , &c., replaces an equivalent quantity of hydrogen. This comparison is ex- 
 pressed by the formulae by which these compounds are represented above ; but their 
 relation to glycol becomes perhaps still more apparent if the. same formulae be written 
 a little differently, so as to be directly comparable with that last given for glycol. 
 Below are the formulae of some of them so written, side by side with sulphur-com- 
 pounds, which may be regarded as of analogous constitution. 
 
 H 
 
 (C 2 H 4 )' 
 
 H 
 
 Glycol. 
 
 Cl [0 
 (S)" 
 
 Cl \ O 
 
 Chlorosul- 
 phuric acid. 
 
 H 
 
 (C 2 H 4 )" 
 
 (C 2 H 4 )" 
 
 K 
 
 (S)" 
 
 Diethylenic Hyposulphite 
 alcohol of potassium 
 
 " potassium 
 
 (= C4HO3). (= S2K2Q3). 
 
 H 
 
 (C 2 H 4 )" 
 
 (C 2 H 4 )" 
 (C 2 H 4 )" 
 (C 2 H 4 )" 
 
 ( T r 
 
 Pentethylenic 
 
 alcohol 
 (= 
 
 K 
 
 (S) " o 
 
 ( sr o 
 ( sr o 
 ( sr o 
 
 T\o 
 
 Pentathionate 
 of potassium 
 
 After these remarks, and what has been previously said about the combinations of 
 polyatomic elements and radicles in general, the following table will be intelligible 
 without further explanation. It gives a list (probably almost complete) of the known 
 compounds containing two or more atoms of the same carbonated radicle, and a few 
 examples of compounds containing radicles composed of other elements, such as sul- 
 phuryl (SO 2 ) and phosphoryl (PO). Many other examples of compounds of a similar 
 nature might be found among mineral substances both natural and artificial, and there 
 can be little doubt that the complex silicates and other minerals belong to this class 
 of compounds. In the table, compounds of the same radicle are arranged on the same 
 horizontal line ; those referable to the same type are arranged in the same vertical 
 column. 
 
CLASSIFICATION. 
 
 1021 
 
 li 
 
 " > 
 
 a ^ 
 
 
 
 
 
 
 ^Tlj 
 
 
 fcfc 
 
 055 . 
 
 r*^*^\ N 
 ^eo 5 
 
 
 
 
 
 
 
 fc| 
 
 c* 
 
 
 
 0*0 
 
 0*: 0* 0* 
 
 
 
 llg^ 
 
 cT'^'s 
 
 
 
 ^T"rt 
 
 nl~.ini| 
 
 
 
 ||11 
 
 |S^ 
 
 
 
 1 
 
 |s^|o^|o 
 
 
 
 "I 
 
 
 
 
 o 
 
 Is, s& 
 
 
 
 i ft 
 
 
 
 
 
 
 illi 
 
 
 3 CQ 
 
 
 
 
 
 
 S-JT* 1 
 
 
 |f= 
 
 
 
 
 
 
 00 3 
 
 
 cl 
 
 O o 
 
 
 
 
 
 60-gd 
 
 
 iii 
 
 '"*' V "" N c* 
 
 
 
 
 
 r *-^* s ^"^^"^ rf g 1 
 
 
 go? 
 
 ^"w a 
 
 
 
 
 
 ^ ^^^g * 
 
 
 11 
 
 2, ^ 
 
 
 
 
 
 1 ^^ll 
 
 
 U 5 
 
 
 
 
 
 
 SB 
 
 
 IB 
 
 o 
 
 " 
 
 
 
 
 
 
 
 
 *- ^* 
 
 O S 
 
 
 
 
 
 c5 
 
 O i 
 
 *O ^" to* 
 
 '~ * 3 
 
 
 
 
 
 '^^-^ O 
 
 *+**\ s a> 
 
 C *5 Q 
 
 
 
 
 
 
 eo 
 
 m G> 
 
 II* 
 
 
 
 
 
 
 a&| 
 
 gjf 9 
 
 e js 
 
 
 
 
 
 
 O M 
 
 
 a l 
 
 ^ 3 
 
 
 
 
 
 
 fa 
 
 ifb 
 
 c 
 
 
 
 
 
 l,|lii 
 
 aj 
 
 III 
 
 a|| 
 
 
 
 
 
 S a 1^*1 1 
 
 i 
 
 13 
 
 o >S 
 
 
 
 
 
 O 3 "E "^ 03 >J 
 
 t. 
 
 s| 
 
 "^ 
 
 
 
 
 
 BE 
 
 
 
 ompounds re- 
 able to the type 
 H8Q*. 
 
 ioj 1 ^ 
 & 5 
 
 
 
 oil 
 
 O -a 6-0 O *g 
 
 BSis| B 5jsfj 
 
 o o o o u o o >? 
 
 
 
 '^^>3- 
 
 (P ^}o- 
 
 Maddrell. 
 (Insoluble 
 etaphosphate.) 
 
 
 1 
 
 *~"*^ 
 
 
 
 
 
 S 
 
 i 
 
 o . 
 
 b a 
 
 o . 1 . 
 
 
 o gf 
 
 
 
 ii 
 
 
 
 ?k^3 sT^Ei 
 
 
 ^J. 
 
 
 
 111 
 
 Js 
 1 
 
 | a l 
 
 H 
 
 5 oo 
 
 
 CO OJS 
 
 CO 
 
 
 
 
 
 
 
 
 t 
 
 *" ' 
 
 
 
 ill 
 
 mds con- 
 he radicle 
 (C2H2O)". 
 
 1 
 
 jnds con- 
 he radicle 
 , (C8H8)". 
 
 II 
 
 || 
 
 ill 
 
 
 D.)S 
 
 0.6*-*" 
 
 ft.''*""- 
 
 E-bc^> 
 
 o. tic a 
 
 1*^ 
 
 ^)0 
 
 
 off 
 
 all 
 
 If! 
 
 III 
 
 j|f 
 
 ||| 
 
 ""Sc 
 
 3i 
 
1022 
 
 CLASSIFICATION. 
 
 Classification according to Types (continued). 
 
 Compounds containing the 
 radicle ethylene, (C 2 H 4 /' 
 (continued). 
 
 Compounds 
 referable to the type 
 
 H9N3. 
 
 Compounds 
 referable to the type 
 
 fCH5jN> 
 H2 ) 
 
 Hofmann. 
 
 Hofmann. 
 
 A little reflection upon what has been said (p. 1017) on the nature of compound 
 radicles, and on the sense in which they are employed, will make it clear that a classi- 
 fication of compounds by means of them, according to types, such as that illustrated 
 in the two tables given, pp. 1018, 1019, 1021, 1022, expresses all we know of their 
 general chemical properties. For the classification of a number of substances as con- 
 taining the same radicle, expresses that they are mutually convertible by comparatively 
 simple processes, that is, that they are genetically related, while the classification of 
 any set of bodies by reference to the same type, expresses that they are capable of 
 undergoing similar transformation, and are therefore functionally related. All our 
 strictly chemical knowledge, however, consists in a knowledge (1) of the nature and 
 proportion of the elements of which substances are composed ; (2) of their genetic 
 relations, or of the bodies from which they can be formed, or to which they can give 
 rise ; and (3) of their chemical functions, or the transformations which they cause or 
 undergo when they react with other bodies. In the foregoing pages, we have accord- 
 ingly endeavoured to point out the leading principles which must be kept in view in 
 classifying chemical substances with reference to considerations of each of these three 
 kinds, considering however at the greatest length the classification of bodies according 
 to their composition ; partly because much less attention has been paid to this 
 subject, in the existing literature of chemistry, than to their genetic and functional 
 relations, but chiefly because composition is the most fundamental of all chemical pro- 
 perties, and the manner in which all other chemical properties depend upon it is the 
 fundamental problem of chemistry. Throughout, we have endeavoured to distinguish 
 between ideas and mere forms of expression, rendered convenient by the existing state 
 of the science. 
 
 The order and system which has been followed in this article, has made it impos- 
 sible to trace the historical development of the ideas therein set forth. The following 
 list of Memoirs of theoretical importance will be of assistance to such readers as wish 
 to trace that development from the birth of Organic Chemistry to the present time ; 
 many other memoirs of equal importance with some of those enumerated, might have 
 been quoted ; but in a large number of these, references are given which will serve as 
 a guide to those who wish to pursue the subject further. 
 
 Lavoisier (Compound radicles), Trait6 elementaire de Chimie (edit. 1789), i. 197, 
 209. 
 
 Dumas and Boullay (Compound ethers}, Ann. Ch. Phys. xxxvii. 15 (1828). 
 
 Wohler and Liebig (Bcnzoyl compounds), Ann. Ch. Pharm. iii. 249 (1832); Ann. 
 Ch. Phys. li. 273. 
 
 Berzelius (Radicle of the bemoic compounds}, Ann. Ch. Pharm. iii. 282; Ann. Ch. 
 Phys. li. 308. 
 
 Berzelius (Radicles of alcohol and its derivatives}, Jahresber. (1833), xiii. 189; 
 Pogg. Ann. xxviii. 617 ; Ann. Ch. Phys. liv. 5; extract, Ann. Ch. Pharm. vi. 173. 
 
 Liebig (Ethyl), Handworterb. d. Chemie (l te Auflage), article Mther ; Ann. Ch. 
 Pharm. ix. 1 ; Pogg. Ann. xxxi. 321 ; Ann. Ch. Phys. Iv. 113 (1834). 
 
 Liebig (Acctyl, constitution of acetic acid, &c.), Ann. Ch. Pharm. xiv. 133 (1835); 
 Pogg. Ann. xxxvi. 275. 
 
 Dumas (Substitution), Ann. Ch. Phys. Ivi. 143 (1835); Traite de Chimie appliquee 
 aux Arts, v. 99 ; J. pr. Chem. vii. 293. 
 
CLAUSTII ALITE CLAY. 1023 
 
 Laurent (Nucleus theory}, Ann. Ch. Phys. Ixi. 125 (1836). 
 
 Gerhardt (Conjugated compounds), ibid. Ixxii. 184 (1838). 
 
 Dumas (Substitution'), Compt. rend. x. 149 ; Ann. Ch. Pharm. xxxiii. 259 (1839). 
 
 Gerhardt (Atomic weights of ^oxygen, carbon, &c.), Ann. Ch. Phys. [3] vii. 129; 
 viii. 238 ; Precis de Chimie organique (1844), i. 47. 
 
 Gerhardt (Homology), Precis, ii. 489. 
 
 Laurent (Law of even numbers of atoms ; nature of the elements in the free state ; 
 monads and dyads}, Ann. Ch. Phys. [3] xviii. 266 (1846) ; Chemical Method, 46 96, 
 e t passim. 
 
 Wurtz (Compound ammonias'), Compt. rend, xxviii. 233, 323 (1849); xxix. 169; 
 Ann. Ch. Phys. [3] xxx. 443 ; Chem. Soc. Qu. J. iii. 90. 
 
 Ho'fmann (Compound ammonias'), PhiL Trans. 1850, i. 93; Chem. Soc. Qu. J. iii. 
 279. 
 
 Williamson (Mixed ethers, etherification), Chem. Soc. Qu. J. iv. 106, 229 (1851). 
 
 Williamson (Constitution of salts), Chem. Soc. Qu. J. ix. 350 (1851). 
 
 Gerhardt and Chancel (Constitution of organic compounds'), Compt. chim. (1851), 
 vii. 65. 
 
 Gerhardt (Basicity of acids), Compt. chim. (1851), vii. 129. 
 
 Gerhardt (Anhydrous organic acids ; classification by types}, Compt. rend, xxxiv. 
 755, 902 (1852) ; Chem. Soc. Qu. J. v. 127, 226 ; more fully Ann. Ch. Phys. [3] 
 xxxvii. 285 ; Dumas's Eeport, Compt. rend, xxxvi. 505. 
 
 Berthelot (Synthesis of fats ; nature of glycerine}, Ann. Ch. Phys. xli. 216 
 (185354). 
 
 Odling (Constitution of salts ; polyatomic radicles}, Chem. Soc. Qu. J. vii. 1(1854). 
 
 Wurtz (Theory of glycerine-compounds ; polyatomic radicles}, Ann. Ch. Phys. [3] 
 xliii. 493 (1855). 
 
 Wurtz (Mixed radicles}, ibid. xliv. 275. 
 
 Gerhardt and Chiozza (Amides}, ibid. xlvi. 129 (1855 56). 
 
 H. L. Buff (Polyatomic radicles}, Proc. Eoy. Soc. viii. 188 (1856). 
 
 Wurtz (Diatomic alcohols}, Compt. rend, xliii. 199; Ann. Ch. Pharm. c. 110; more 
 fully, Ann. Ch. Phys. [3] Iv. 400 (185659). 
 
 Kekule (Mixed types, radicles, &c.), Ann. Ch. Pharm. civ. 129 (1857). 
 
 Kekule (Ditto; tctratomic character of carbon}, ibid. cvi. 129 (1858). 
 
 Couper (Atomicity of carbon and oxygen}, Ann. Ch. Phys. [3] liii. 504 (1858); 
 Ann. Ch. Pharm. ex. 46 (here followed by critique by Buttlerow, 1859). 
 
 Kolbe (Constitution of lactic acid}, Ann. Ch. Pharm. cix. 257 (1859) ; same subject, 
 ibid, cxiii. 223 (1860). 
 
 Foster (Nature of radicles and types}, Brit. Assoc. Reports, 1859, 1. 
 
 Wurtz (Basicity of acids}, Ann. Ch. Phys. [3] li. 342 (1859). 
 
 Cahours (Combining capacity of the elements; limits of combination}, Ann. Ch. 
 Phys. [3] Iviii. 5 (1860). 
 
 Frankland (Same subject}, Chem. Soc. Qu. J. xiii. 177 (1860). 
 
 Wurtz (Constitution of lactic acid), Ann. Ch. Phys. [3] lix. 161 (1860). 
 
 Cahours (Same subject), Ann. Ch. Phys. [3] xii. 257 (1861). 
 
 Buttlerow (Atomicity of the elements), Zeitschr. Chem. Pharm. iv. 549 (1861). 
 
 Erlenmeyer (Same subject), ibid. v. 18 (1862). 
 
 Kolbe (Classification of organic bodies), Ann. Ch. Pharm. cxiii. 293 (1860); 
 Critical remarks by Wurtz, Rep. Chim. pure, ii. 354. 
 
 Laurent, Methode de Chimie, 1844; Cavendish Society's translation, 1855. 
 
 Gerhardt, Trait6 de Chimie organique, 4 vols. 185356; especially i. pp. 121 
 142, iv. pp. 561808. 
 
 Kekule, Lehrbuch der organischen Chemie, vol. i. (1859 61). 
 
 Odling, Manual of Chemistry, part i. ( 1 8 6 1 ). G. C. F. 
 
 CX. AT7STH AX.XTS. Native selenide of lead. (See LEAD.) 
 CX.AY. This term is applied to hydrous silicates of aluminium, produced for the 
 most part by the decomposition of felspar rocks, and generally mixed with small quan- 
 tities of other substances, chiefly lime, magnesia, and oxide of iron. The clays exhibit 
 the following general characters : They are opaque, non-crystallised bodies, suffi- 
 ciently soft to be scratched by iron ; they have a dull or even earthy fracture ; they 
 exhale, when breathed on, a peculiar smell called argillaceous. The clays form with 
 water a plastic paste, possessing considerable tenacity, which hardens with heat, so as 
 
1024 CLAY. 
 
 to strike fire with steel. Marls and chalks also soften in water, but their paste is not 
 tenacious, nor does it acquire a siliceous hardness in the fire. The affinity of the 
 clays for moisture is manifested by their sticking to the tongue, and by the intense 
 heat necessary to make them perfectly dry. Those which contain iron turn red when 
 burnt. Clay is often mixed with quartz, and contains fine particles of felspar, mica, and 
 beryl, showing that it has been produced by the decomposition of felspar or granite. 
 The principal varieties of clay are the following : 
 
 1. Porcelain earth, the kaolin of the Chinese. This mineral is friable, meagre to the 
 louch, and, when pure, forms with difficulty a paste with water. It is infusible in a 
 porcelain furnace. It is of a pure white, verging sometimes upon the yellow or flesh- 
 red. Some varieties exhibit particles of mica, which betray their origin to be from 
 felspar or graphite granite. Porcelain clay scarcely adheres to the tongue. Specific 
 gravity 2'2. The average composition of kaolin, when separated from free silica and 
 undecomposed felspar, is 47 per cent, silica, 40 alumina, and 13 water, agreeing 
 with the formula Al 4 8 .2Si0 2 + 2 aq. It may be supposed to be formed from orthoclase, 
 K 2 O.Al 4 3 .6Si0 3 , by abstraction of the whole of the potash and | of the silica, and 
 addition of 2 at. water. Some varieties, however, exhibited a different composition ; 
 thus the kaolin of Passau contains, according to Fuchs, 43*65 per cent. SiO 2 , 35*93 ATO 3 , 
 I'OO Fe 4 8 , and 18*50 water, besides 0*88 carbonate of calcium, a composition which 
 may be approximately represented by the formula 4Al 4 3 .9Si0 2 + 12 aq. Porcelain 
 clay from Gutenberg, near Halle, contains, according to Bley, 39-02 SiO 2 , 45-00 A1 4 3 , 
 and 10*00 water, together with 0'07 carbonate of calcium, 3'32 carbonate of magnesium, 
 and 0-19 sesquioxide of iron, agreeing approximately with 2Al 4 3 .3Si0 2 4 3aq. (Eam- 
 onelsberg's Mineralchemie, p. 574). In two specimens of Chinese kaolin, Ebelmen 
 and Salvetat (Ann. Ch. Phys. xxxi. 257) found 73'4 and 80'7 SiO 2 , 44-5 A1 4 3 , 14-4 
 and 12'0 water; in these the quantity of silica is twice as great, in proportion to the 
 alumina, as in the ordinary formula of kaolin (Dana, ii. 250). Kaolin is found in 
 primitive mountains, amid blocks of granite, forming interposed strata. Kaolins are 
 sometimes preceded by beds of a micaceous rock of the texture of gneiss, but red and 
 very friable. This remarkable disposition has been observed in the kaolin quarries of 
 China, in those of Alen9on,and of St. Yrieux, near Limoges. The Chinese and Japanese 
 kaolins are whiter and more unctuous to the touch than those of Europe. The Saxon 
 has a slight tint of yellow or carnation, which disappears in the fire, and therefore is 
 not owing to metallic impregnation. At St. Yrieux, the kaolin is in a stratum, and 
 also in a vein, amid blocks of granite, or rather the felspar rock which the Chinese 
 call petuntze. The Cornish kaolin is very white and unctuous to the touch, and is 
 obviously formed by the disintegration of the felspar of granite. 
 
 2. Potters' clay, or plastic clay. The clays of this variety are compact, smooth, and 
 almost unctuous to the touch, and may be polished by the finger when they are dry. 
 They have a great affinity for water, form a tenacious paste, and adhere strongly to 
 the tongue. The paste of some is even slightly transparent. They acquire great so- 
 lidity, but are infusible in the porcelain furnace. This property distinguishes them 
 from the common clays employed for coarse earthenware. Some of them remain white, or 
 become so in a high heat ; others turn red. Specific gravity about 2. The slaty potters' 
 clay of Werner has a dark ash-grey colour ; principal fracture imperfectly conchoidal, 
 cross fracture earthy; fragments tabular, rather light; it feels more greasy than 
 common potters' clay. Vauquelin's analysis of the plastic clay of Forges-les-Eaux, 
 employed for making glass-house pots, as well as pottery, gave 16 alumina, 63 silica, 
 1 lime, '8 iron, and 10 water. Another potters' clay gave 33 - 2 and 43*5, of alumina and 
 silica, with 3 -5 lime. 
 
 Fire-clay is a very refractory plastic clay, much used in the manufacture of fire-bricks, 
 glass-house pots, &c. In this country it lies immediately beneath the coal, each bed 
 of which rests upon a stratum of this clay, hence called in the mining districts under- 
 day. The Stourbridge clay is of this character. (See FIRE-CLAY.) 
 
 3. Loam. This is an impure potters' clay mixed with mica and iron ochre. Colour 
 yellowish-grey, often spotted yellow and brown. Massive, with a dull glimmering 
 lustre from scales of mica. Adheres pretty strongly to the tongue, and feels slightly 
 greasy. Its density is inferior to the preceding. 
 
 4. Variegated clay is striped or spotted with white, red, or yellow. Massive, with an 
 earthy fracture, verging on slaty. Shining streak. Very soft, sometimes even friable. 
 Feels slightly greasy, and adheres a little to the tongue. Sectile. It is found in 
 Upper Lusatia. 
 
 5. Slate clay. Colour grey, or greyish-yellow. Massive. Lustre dull or glim- 
 mering from interspersed mica. Fracture slaty, approaching sometimes to earthy. 
 Fragments tabular. Opaque, soft, sectile, and easily broken. Specific gravity 2'6. 
 Adheres to the tongue, and breaks down in water. It is found along with coal, and in 
 the floetz trap formation. 
 
CLAY-SLATE CLINOCHLORE. 1025 
 
 6. Claystonc. Colour grey, of various shades, sometimes red, and spotted or 
 striped. Massive. Lustre dull, with a fine earthy fracture, passing into fine-grained 
 uneven, slaty, or splintery. Opaque, soft, and easily broken. Does not adhere to the 
 tongue, and is meagre to the touch. It has been found on the top of the Pentland 
 hills in Scotland, and in Germany. 
 
 7. Adhesive slate. Colour light greenish-grey. Internal lustre dull; fracture in 
 the large, slaty; in the small, fine earthy. Fragments slaty. Opaque. Streak 
 shining. Sectile. Easily broken or exfoliated. Adheres strongly to the tongue, and 
 absorbs water rapidly, with emission of air bubbles and a crackling sound. It is 
 found at Montmartre, near Paris, between blocks of impure gypsum, in large straight 
 plates like sheets of pasteboard ; also at Menilmontant, enclosing menilite. Klaproth's 
 analysis gives 62*5 silica, 8 magnesia, 0'5 alumina, 0-25 lime, 4 oxide of iron, 22 
 water, and 075 charcoal. Its specific gravity is 2*08. 
 
 8. Polishing slate of Werner. Colour cream-yellow, in alternate stripes. Massn e. 
 Lustre dull. Slaty fracture. Fragments tabular. Very soft, and adheres to the 
 tongue. Smooth, but meagre to the touch. Specific gravity in its dry state 0*6 ; 
 when imbued with moisture 1'9. It has been found only in Bohemia. Its consti- 
 tuents are, 79 silica, 1 alumina, 1 lime, 4 oxide of iron, and 14 water. 
 
 9. Common day may be considered to be the same as loam. Besides the above, we 
 have the analyses of some pure clays, the results of which show a very minute quan- 
 tity of silica, and a large quantity of sulphuric acia. Thus, in one analysed by Bu- 
 cliolz, there was 1 silica, 31 alumina, 0-5 lime, 0'5 oxide of iron, 21-5 sulphuric acid, 
 45 water, and 1*5 loss. Simon found 19'35 sulphuric acid in 100 pts. These clays 
 must be regarded as basic sulphates of aluminium. U. 
 
 For analysis of various clays, see Ure' 's Dictionary of Arts, Manufactures and Mines, 
 i. 691. 
 
 CZiA.Y-SIiA.TE. Argillaceous schist ; the Argillite of Kirwan. Colour bluish- 
 grey and greyish-black of "various shades. Massive. Internal lustre shining or pearly. 
 Fracture foliated. Fragments tabular. Streak greenish-white. Opaque. Soft. Sec- 
 tile. Easily broken. Sonorous when struck with a hard body. Specific gravity 2*7. 
 Its constituents are 48'6 silica, 23'5 alumina, 1*6 magnesia, 1T3 sesquioxide of iron, 0*5 
 oxide of manganese, 47 potash, 0'3 carbon, O'l sulphur, 7'6 water and volatile matter. 
 Clay-slate melts easily before the blowpipe into a shining scoria. This mineral is ex- 
 tensively distributed, forming part of both primitive and transition mountains. The 
 great beds of it are often cut across by thin seams of quartz or carbonate of lime, 
 which divide them into rhomboidal masses. Good slates should not imbibe water. If 
 they do, they soon decompose by the weather. U. 
 
 CX.jA.lT IRON-STONE. See IRON. 
 
 CZiAYITE. A mineral from Peru, occurring crystallised and as a crust f of an 
 inch thick on quartz. It appears to be composed of the sulpharsenites of copper and 
 sulphantimonites of copper and lead. The crystals belong to the regular system, being 
 combinations of the tetrahedron with the rhombic dodecahedron. Colour blackish- 
 grey. Streak the same. Lustre metallic. Hardness = 2*5. Sectile. Melts easily 
 before the blowpipe, and gives the reactions of lead, arsenic, and antimony. With 
 soda it yields a metallic globule, which becomes dull on cooling. Possibly a pseudo- 
 morph of fahl-ore. (W. J. Taylor, SilL Am. J. [2] xxix. 367.) 
 
 CE.EAVAGE OF CRYSTALS. See CRYSTALLOGRAPHY. 
 
 CZ,ELavx,AOTSJXTj3. Soda-felspar. (See FELSPAR.) 
 
 CliSOPH AlffE. Syn. with blende or native sulphide of zinc. (See ZINC). 
 
 CLEIVIATIS-CAIVIPHOR. The young branches of Clematis flammula, Cl. vi- 
 talba, Cl. viticella, Cl. erecta, &c., yield by distillation with water, a liquid which has a 
 sharp taste, a pungent odour of radish, and reddens the skin ; when exposed to the 
 air, it loses its acidity, and if left to stand in closed vessels, deposits white scales and 
 flocks of clematis-camphor. (Braconnot, Ann. Ch. Phys. vi. 734.) 
 
 CX.XHVEATXTXXT. A bitter substance, perhaps C 9 H 10 8 , obtained by Walz from 
 the root of Aristolochia clematitis (i. 357). 
 
 CIiINGlVIANNTTE. Syn. with MARGARITE (q. v.) 
 
 CLINKSTONE or PHORTOIiXTE is a compact felspathic rock, of greyish colour 
 and smooth fracture, clinking when struck with a hammer, somewhat like a metal. 
 Specific gravity = 2-2 2'4. 
 
 CIiIKTOCHXiORE. A mineral having the same composition as chlorite (i. 913), 
 but differing from it in crystalline form, inasmuch as it belongs to the trimetric system, 
 whereas chlorite is rhombohedral. The crystals of clinochlore are hemihedral, and 
 
 VOL. I. 3 U 
 
1 026 CLINOCL ASE CLOUDS 
 
 have a micaceous structure, the crystallising planes often forming equilateral triangles. 
 It is optically biaxial, the angle between the axes being 84 30' (or 80 to 86) ; the 
 plane of the axes is perpendicular to the cleavage-sui*face, but the two axes are un- 
 equally inclined to this surface, one at 54 the other at 30. It occurs in large crystals, 
 usually having a rhombohedral aspect, and in plates ; often compounded, the crystals 
 giving a second pair of optical axes, making an angle of 60 with the other. Specific 
 gravity about 2*714. Hardness 2 2-5. Lustre somewhat pearly. Colour olive- 
 green. Transparent, unless in thick plates. Somewhat elastic. 
 
 Analyses. a, b, from Chester county, Pennsylvania, by W. J. Craw (Sill. Am. J. [2] 
 xiii. 222); c, from Lisgau, Bavaria, Kobell (Gel. Anzeige, 1854, No. 43) : 
 
 SiO 2 A1 4 3 Fe 4 3 Cr 4 3 Mg*0 H 2 
 a. 31-34 17-47 3-85 1-69 33-44 12-60 = 100-39 
 
 b. 31-78 22-71 33-64 12-60 = 100-72 
 
 c. 33-49 15-87 2-30 0-55 32-94 11-50 Fe 2 4-25 = 100-40 
 
 Before the blowpipe it behaves like chlorite, showing traces of fusion on the edges. 
 (Dana, ii. 294.) 
 
 CLIIJGC^ASE. Syn. with ABICHITE (i. 1). 
 
 CIiI WTO WITH. Scybertite, Holmesite, Chrysophane. A silicate found at Amity, 
 New York, in limestone connected with serpentine, together with augite, hornblende, 
 spinel, and graphite. It forms small tabular crystals or foliated masses, sometimes 
 lamellar, radiate. Stru ^ture thin, foliated, or micaceous, parallel to the base. According 
 to Breithaupt, the crystals are monoclinic, with the angles between the lateral planes 
 = 94. Specific gravity == 3 3'1. Hardness = 4 5. Lustre pearly, submetallic. 
 Colour reddish-brown, yellowish or copper-red. Streak uncoloured, or slightly yel- 
 lowish or greyish. Folia brittle. 
 
 Closely allied to clintonite are Xanthophyllite, from Slatoust in the Ural, where it 
 occurs in implanted globules, and in columnar or lamellar individuals, sometimes en- 
 closing small hexagonal crystals secondary to a rhombic prism, and Disterrite or Bran- 
 disite, occurring in the Fassa valley, Tyrol, in hexagonal prisms of specific gravity 
 3-042 5-051, and hardness = 5 on the base, 6 6'5 on the sides. 
 
 Analyses. a, Seybertite, by Clem son (Sill. Am. J. xxiv. 17 !)-&, Holmesite, by 
 Richardson (Rec. Gen. Sci. May, 1836). c, Clintonite, by Brush (Sill. Am. J. 
 [2] xviii. 407). d, Xanthophyllite, by G. Rose (Pogg. Ann. i. 654). d, Disterrite or 
 Brandisite, by Kobell (J. pr. Chem. xli. 154) : 
 
 Ca?O K 2 O Na2Q R2Q F 
 
 a. 17-0 - 37-6 5'5 24-3 10-7 3'6 _ = 987 
 
 b. 19-35 2-05 44-75 4'80 1-35 9'05 11 45 4-55 0"90 = 98 25 
 
 c. 20-18 0-19 38-90 3-87 21-25 13-52 0*29 1-14 1-04 = 100-41 
 
 d. 16-30 43-95 '2-81 19-31 13-26 0'61 4'33 = 100-57 
 
 e. 20-00 43 22 3-(;0 2V01 4'00 0'57 3 60 =100 
 
 These results may be approximately represented by the following formulae, in which 
 M denotes a uni-equivalent and R a sesquiequivalent metal : 
 
 Clintonite (Seybertite, Holmesite) . 2M 2 0.3Si0 2 + 2(3M 2 0.2R<0 S ) 
 
 Xanthophyllite 2M 2 0.3Si0 2 + 3(3M 2 0.2R 4 3 ) + 3aq. 
 
 Disterrite 2M 2 0.3Si0 2 + 4(M 2 O.R 4 8 ) + 2aq. 
 
 It is doubtful whether either of these minerals has been found in an unaltered state. 
 
 Clintonite is infusible before the blowpipe, but loses its brown colour and becomes 
 opaque ; heated in a flask it gives off neutral water. It is completely decomposed by 
 hydrochloric acid. 
 
 Xanthophyllite yields green glasses with fluxes : it is decomposed by acids, like 
 clintonite, but much less easily. 
 
 Disterrite when heated gives off water, which is neutral or alkaline, according as 
 the specimen is fresh or has turned red-brown by weathering. Before the blowpipe it 
 becomes turbid and greyish-white, but does not fuse ; with fluxes it gives the reac- 
 tions of iron and silica. It is not sensibly attacked by hydrochloric acid ; but sul- 
 phuric acid decomposes it when heated with it for some time. (Rammelberg's 
 Mineral chemi>, p. 848. Dana, ii. 297.) 
 
 CXiOT71>S are masses of air which contain innumerable minute particles of sus- 
 pended water condensed from a state of vapour, and thus assume the appearance of 
 white or misty bodies. The forms of clouds, which of course depend on the form and 
 motions of the mass of air, were first properly classified by Howard, (Bees' Cyclopedia, 
 art. CLOUD; Nicholson's Journal, 1811, xxx. 35 62 ; or Howard's Climate of London, 
 2nd ed. vol. i.), whose arrangement we may thus shortly describe 
 
CLOUDS. 1027 
 
 Cirrus. Parallel, flexuous, or diverging fibres, commonly called mare-tails, occur- 
 ring most distinctly in the higher regions of the atmosphere, but sometimes originating 
 from large masses of other cloud at lower elevations. The adjective cirrose may be 
 applied to any streaked appearance in clouds. 
 
 Cumulus. Convex or conical heaps, increasing upward from a horizontal base. 
 This is the most abundant form of cloud, generally appearing during the day at a 
 moderate elevation, and moving along with the current next the earth. 
 
 Stratus. A widely extended continuous horizontal sheet, either lying upon the sur- 
 face of the earth as a mist, or elevated at any height in the atmosphere. 
 
 Cirrostratus. Stratus streaked with the fibres of the cirrus. This form of cloud, 
 generally occurring at a great elevation, and consisting, therefore, of particles of ice, 
 is the cause of solar and lunar halos, and also of the parhelion and paraselene. 
 
 Cumulostratus. A cumulus the summit of which spreads laterally, producing an 
 anvil-shaped cloud. This kind of cloud is very likely to turn to the following : 
 
 Nimbus, Cumulo-cirro-stratus, Sain, or Thundercloud is a cloud or system of clouds 
 forming a great sheet or mass, mostly cumulose, but with lateral stratose extensions, 
 and with tufts of cirrus spreading from the summit. It indicates a great distur- 
 bance of the atmosphere, caused by a violent upward current in the centre of the 
 cloud, and is generally accompanied by wind or squalls. 
 
 The following further statements are on the authority of Howard. 
 
 The cumulus has the densest structure, and is formed in the lower atmosphere. A small 
 irregular spot first appears, and is, as it were, the nucleus on which the mass increases. 
 The lower surface continues irregularly plane, while the upper rises into conical or hemi- 
 spherical heaps, which may afterwards long continue nearly of the same bulk, or rapidly 
 rise into mountains. They will begin, in fair weather, to form some hours after 
 sunrise, arrive at their maximum in the hottest part of the afternoon, then go on 
 diminishing, and totally disperse about sunset. Previotis to rain, the cumulus increases 
 rapidly, appears lower in the atmosphere, and with its surface full of loose fleeces or 
 protuberances. The formation of large cumuli to leeward in a strong wind indicates 
 the approach of a calm with rain. When they do not disappear or subside about sunset, 
 but continue to rise, thunder is to be expected in the night. 
 
 The stratus has a mean degree of density, and is the lowest of clouds, its inferior 
 surface commonly resting on the earth or water. This is properly the cloud of night, 
 appearing about sunset. It comprehends all those creeping mists, which in calm 
 weather ascend in spreading sheets (like an inundation of water), from the bottom 
 of valleys and the surfaces of lakes and rivers. On the return of the sun, the level 
 surface of this cloud begins to put on the appearance of cumulus, the whole at the 
 same time separating from the ground. The continuity is next destroyed, and the 
 cloud ascends and evaporates, or passes off with the appearance of the nascent cumulus. 
 This has long been regarded as a prognostic of fair weather. 
 
 The cirrus having continued for some time increasing or stationary, usually passes 
 either to the cirro-cumulus or the cirro-stratus, at the same time descending to a 
 lower station in the atmosphere. This modification forms a very beautiful sky, is fre- 
 quent in summer, and attendant on warm and dry weather. The cirro-stratus, when 
 seen in the distance, frequently gives the idea of shoals of fish. It precedes wind 
 and rain, is seen in the intervals of storms, and sometimes alternates with the cirro- 
 cumulus in the same cloud, when the different evolutions form a curious spectacle. 
 A judgment may be formed of the weather likely to ensue, by observing which 
 modification prevails at last. 
 
 Howard did not explain the special causes of forms of clouds above described, nor 
 can we point to more than one or two attempts at all sound and scientific to accom- 
 plish this. In two papers, however, in the Philosophical Magazine (4th ser. xiv. 22 ; 
 xv. 241), it is shown, by analogical experiments with liquids, that the cirrus arises from 
 the interjiltration of masses of air saturated with moisture, and not in equilibrium ; 
 the stratus, from mixture or contact of layers of air tranquilly moving on or lying 
 over each other, while the cumulus arises from the violent ascent of columns of air 
 in the atmosphere. The nimbus, rain, or thundercloud appears to be formed in like 
 manner. 
 
 Very little is known of the nature of clouds from which slow long-continued rain 
 falls, as it so commonly does in London, but the cloud is probably for the most part 
 stratose. 
 
 More particular accounts of the phenomena of the clouds and weather must be 
 sought in works on meteorology, among which by far the most philosophical and reliable, 
 is Sir J. Herschel's Essay on Meteorology (Encyc. Brit. 8th ed.). To this Essay 
 we are indebted for some of the following remarks. 
 
 It is more within the province of the chemist to consider the nature of the matter 
 
 3 u 2 
 
1028 CLOUDS. 
 
 of clouds. Meteorologists have generally assumed, as an unsupported dogma, that 
 cloud particles are small vesicles or watery bubbles. Saussure, indeed, is said to have 
 examined these vesicles in the mists of high mountains, and to have found them vary 
 in size from ^ inch to the ^^ inch, occasionally however attaining the size of a 
 pea. Now although no observer is in general more deservedly trusted than Saussure, 
 his unsupported announcements must not always be adopted as conclusive, and we are 
 quite unaware of any one else having witnessed vesicles of appreciable size floating in 
 the air and forming clouds or mists. It is also stated ( Graham's Elements, 2nd ed. 
 i. 314), that the vesicles may be observed by a lens of an inch focal length, over the 
 dark surface of hot tea or coffee, mixed with an occasional solid drop, which contrasts 
 with them. Having tried this, we witnessed a white dust of watery particles of 
 uniform size, blowing about over the surface of the coffee, or rising in little wreaths 
 and whirlwinds like dust on a windy day, but we saw no drops appearing solid as con- 
 trasted with the rest, and were inclined to consider them all solid particles of about 
 the diameter of ^od inch. No one has ever suggested how the vesicles are formed, 
 nor is it easy to conceive any possible mode of their formation. 
 
 In favour of the vesicular theory, it may be urged that rainbows are at least very 
 seldom produced when the sun shines on cloud or on steam, although a rainbow is ex- 
 hibited under such circumstances by the minutest rain and by spray from a fountain 
 or waterfall. Sir J. Herschel suggests that the particles may be of an order of small- 
 ness comparable to the lengths of the light-undulations, which are on an average 
 about soTioo i ncn l n g- Hence, he infers, the refractions and reflections of light which 
 cause the rainbow would not take place. (See also Raillard, Comptes Eendus, 
 xliii. 906.) 
 
 The existence of vesicular vapour of water seems, however, to have been disproved 
 by the microscopic observations of Dr. A. Waller (Phil. Trans, cxxxvii. [1847] 
 p. 23), which later writers have overlooked. Steam being thrown upon a surface of 
 Canada balsam, the particles of water became fixed and were easily examined in the 
 microscope. It was concluded that whenever we are enabled to inspect the minutest 
 particles of water arising from condensed steam or vapours, they consist of minute 
 liquid globules without any appearance of internal cavity. 
 
 The suspension of the clouds is in no way mysterious, and arises only from the 
 enormous comparative resistance which the air offers to the motion of a very minute 
 body, as Prof. Stokes has lately shown (Cambridge Phil. Trans, vol. viii. ix.) A 
 globule of water of the diameter of ~^ inch, in falling through the air, would have the 
 maximum velocity of about -067 inch per second, which is quite inappreciable com- 
 pared with the ascensional movement of the air, which is generally taking place 
 in all large masses of cloud. The watery particles, or the air, generally both, must 
 then be in motion in every cloud. (See also Phil. Trans, vol. Iv. [1765] p. 162.) 
 
 No satisfactory reason has ever been given why the clouds only sometimes dis- 
 charge rain, but it is not difficult to see that if all the particles were of equal size, they 
 would all subside at exactly the same rate, and no collisions could take place. But if 
 a further set of particles were precipitated of a different size they would move at a 
 different rate, and encounter the other particles ; many particles would thus coalesce 
 into drops of sufficient size to fall rapidly, and receiving accretions in their passage 
 through the air, reach the surface of the earth as rain. The coalescence of minute 
 globules vastly diminishes their surface as compared with their bulk ; it is easy then 
 to understand how electric tension existing on the surface of cloud particles is so in- 
 tensified when rain falls as to occasion lightning. This theory of the thundercloud 
 was suggested as early as 1752 by Eeles (PhiL Trans, p. 527), and it is repeated in 
 the papers in the Philosophical Magazine before referred to. 
 
 There are two principal ways in which cloud particles are produced : 
 
 1. A gas in changing its volume also changes its temperature, and may thus bo 
 unable to sustain in the gaseous state all the aqueous vapour which is diffused through 
 it. Thus, if the air within the receiver of an air-pump be moist, a few strokes of the 
 pump will produce a visible mist. In the atmosphere, by far the largest masses of clouds 
 are thus produced by columns of air rising, and consequently expanding and growing 
 cold as they rise. Fogs, it is also said, may be produced at the surface by sudden 
 changes of barometric pressure. 
 
 2. Two masses of moist air of different temperatures will not, when mixed, sustain 
 the whole of the contained vapour in the gaseous state : for the maximum tension of 
 aqueous vapour varies in a higher ratio than the temperature. Hence the mean ten- 
 sion of vapour on mixing, will always be higher than the tension possible at the mean 
 temperature, and vapour will be condensed until the two are equalised. Thus arise 
 the cirrose and stratose forms of cloud, from the mixing of bodies of air under various 
 circumstances. 
 
 Gases have but an inappreciable power of conducting heat. A cold surface may 
 
CLOVES COAL. 1029 
 
 rndeed condense vapour from the air, as in the formation of dew, but the water con- 
 densed will all attach itself to the cold surface, and no cloud-particles will be produced. 
 Dr. Tyndall having lately proved that gases may radiate heat, it is possible that clouds 
 may be produced in the higher parts of the atmosphere by slow radiation. W. S. J. 
 
 CZiOVSS, OH OP. Gcwurznelkenbl. This oil, obtained by distilling with 
 water the buds and flower-stalks of the clove-tree, Eugenia caryophyllata, or 
 Cart/ophyllus aromaticus, L., is a mixture of eugenic acid (q. v.) and a hydrocarbon, 
 C 10 il 16 , isomeric with oil of turpentine. This hydrocarbon passes over with vapour of 
 water, when the crude oil of cloves is distilled with potash-ley. It is highly refrac- 
 tive, has a density of 0-918 at 18 C., and boils at 142 143. It is not attacked 
 by alkalis ; it absorbs a large quantity of hydrochloric acid, and without forming a crys- 
 talline compound (Ettling, Ann. Ch. Pharm. Ix. 68). "Water distilled from cloves 
 sometimes deposits nacreous scales of eugenin, a substance probably isomeric with 
 eugenic acid. 
 
 According to Stenhouse (Ann. Ch. Pharm. xcv. 103), the so-called oil of cinna- 
 mon-leaf is likewise a mixture of eugenic acid and a hydrocarbon, C 10 H 16 . It has a 
 density of 0'862, and boils at 160 165 C. ; it contains also a small quantity of 
 benzoic acid. 
 
 CliOVORUBRlMT. A resinous body produced by the action of sulphuric acid on 
 oil of cloves. 
 
 7VIOSS. See LYCOPODIUM. 
 
 CLUTHAIiITE. A mineral related to analcime (p. 210), occurring in flesh-red 
 vitreous crystals in the amygdaloid of the Kilpatrick Hills. Specific gravity = 2'166. 
 Hardness - 3'5. Opaque or subtranslucent. Fragile. Contains 51-27 SiO 2 , 23 - o6 
 A1 4 3 , 7-31 Fe 4 3 , 5'13 Na 2 0, 1-23 Mg 2 0, and 10-55 water = 99'05. (Thomson, 
 System of Mineralogy, i. 339.) 
 
 CRTICIRT. Centaurin. (Morin, J. Chim. md. iii. 105; Scribe, Compt. rend. 
 xv. 803). A bitter substance contained in Ccntaurea bcnedictus or Cnicus benedictns 
 (Morin); also in the leaves of Centaur ea calcitrapa, and in all bitter plants of the 
 order Composites, sub-order Cynarocephalce (Scribe). Morin first obtained it in an 
 impure state by treating the alcoholic extract of Ccntaurea benedictus with ether, 
 evaporating, precipitating with sub-acetate of lead, evaporating the filtered liquid after 
 freeing it from lead, and treating the residue with ether and alcohol. It was after- 
 wards obtained by Nativelle and further examined by Scribe. 
 
 Cnicin forms white transparent silky needles, inodorous, having a pure bitter taste, 
 and neutral reaction, easily soluble in alcohol and wood-spirit, very little soluble in 
 ether. The alcoholic solution deflects the plane of a polarised ray to the right; 
 [a] = + 130'68 (Bouchardat). It is nearly insoluble in cold water, dissolves 
 somewhat more easily in warm water. The solution is decomposed by continued boil- 
 ing, becoming turbid and afterwards depositing a viscid body like turpentine. 
 
 Cnicin gives by analysis 62'9 per cent, carbon, 7*0 hydrogen, and 30*1 oxygen, 
 whence have been deduced the three formulas C 14 H 18 5 , C-H 26 CT, and C^H^O 9 . -They 
 all agree pretty nearly with the analysis, but as there is no means of determining the 
 atomic weight of cnicin, it is impossible at present to decide between them. 
 
 Cnicin submitted to dry distillation gives off vapours and becomes carbonised. Strong 
 sulphuric acid dissolves cnicin with deep blood-red colour, the liquid becoming black 
 when heated. Strong hydrochloric acid is coloured green by it ; if heat be applied, 
 the liquid turns brown, and oily drops collect on its surface, solidifying in a resinous 
 mass on cooling. 
 
 COAGUXiUlVI is a term applied to any viscid or curdy mass separated from a 
 liquid, as cheese from milk, the clot from blood, &c. 
 
 CO AIi. Houille. SteinJcohle. The vast masses of fossil fuel which are stored up 
 within the bowels of the earth, and in particular constitute so essential an element of 
 our national prosperity, are undoubtedly the result of complex chemical changes, acting 
 under varying circumstances of temperature, pressure, moisture, &C.. either upon vege- 
 table matter growing on the spot, or upon the remains of plants collected by the drift of 
 rivers, &c., into particular localities. 
 
 The vegetable origin of coal is beyond doubt, nor can there be any question as to the 
 character of the flora of the carboniferous era, about 500 distinct species, including 
 250 ferns, having been recognised as belonging to that period. 
 
 The discovery of distinct ligneous structure in most kinds of coal appears, however, 
 to be somewhat questionable ; and although Bischof and others have entered into in- 
 teresting and highly valuable speculations as to the precise changes, by virtue of which 
 
1030 
 
 COAL. 
 
 woody matter may be converted into coal, the microscopic and chemical examination 
 of the substances themselves, do not afford direct proof of the accuracy of these con- 
 ceptions. 
 
 The conversion of wood into coal, according to Bischof, may take place in four dif- 
 ferent ways, viz. : 
 
 1. By separation of carbonic acid and carburetted hydrogen. 
 
 2. water. 
 
 3. carburetted hydrogen and water. 
 
 4. 
 
 carbonic acid. 
 
 (For the formulae representing these changes we refer the reader to Bischof s Chemical 
 and Physical Geology, vol. i. p. 274, et. scq.) 
 
 " When wood or vegetable matter, then, is buried under circumstances which allow 
 of the extrication of these substances from it, in the course of its decomposition, it must 
 become con verted into coal; the extreme result of the process being to give us, first anthra- 
 cite, containing perhaps 94 per cent, of carbon, and finally graphite, which is either 
 pure carbon itself, or that substance mingled with others which are here excluded from 
 consideration, as not being among the elements of wood, and which it may have ac- 
 quired from external sources during the process of conversion. 
 
 " The great quantities of carbonic acid gas (choke-damp), and carburetted hydrogen 
 (fire damp) met with in coal mines, show the fact of the large extrication of these sub- 
 stances, and corroborates, if need were, this explanation. Reservoirs of these gases 
 in a highly compressed state are often found to be pent up in the crevices and cavities 
 of coal beds. Some beds of coal are so saturated with gas, that when they are cut 
 into, it may be heard oozing from every pore of the rock, and the coal is called by 
 the colliers ' singing coal.' " (Bee te Jukes, Manual of Geology.') 
 
 The natural escape of light carburetted hydrogen, marsh-gas or fire-damp (CH 4 ), 
 which frequently bursts forth in large quantities from the seams of coal or strata of 
 fire-clay which divide them, is the frequent cause of those terrible accidents, of which 
 the Lund Hill Colliery explosion in 1857, and the still more recent one at Burradon, 
 have been the most calamitous upon record. 
 
 The sudden issue of gas from a blower in the colliery adjacent to that of Lund Hill 
 is thus described. " The fire-clay of the floor of the seam was seen to heave at dif- 
 ferent points along the face, and presently large fractures were made in it, through 
 which gas was ejected with great violence and with a sound very similar to the issue 
 of steam at a high pressure from a boiler." Subsequent to the explosion at Lund 
 Hill, the pent up gas still issuing within the mine in the higher parts of the workings 
 supported two columns of water 30 feet high, one 10 feet and the other \\~ feet, dia- 
 meter, corresponding to a pressure of about 11 Ibs. on the square inch. This gas in ex- 
 ploding renders unfit for respiration 10 times its own bulk of air: hence the "after 
 damp " of the miner, the vitiated atmosphere produced by the explosion, often fatal to 
 those working in other parts of the mine, or to those who descend into the pits without 
 proper precautions, or until ventilation has been sufficiently re-established. 
 
 " The subjoined tables, given by Miller, give an idea of the composition of wood 
 and will illustrate the progress of its decay. They also furnish a synoptic view of the 
 composition of some of the principal varieties of coal, in the order of their occurrence 
 in successive geological stages. The proportion of oxygen diminishes rapidly and that 
 of hydrogen more slowly, as the coal passes from lignite towards anthracite, in which 
 form it consists of nearly pure carbon." 
 
 Composition of Wood and Coal. 
 
 
 Oak-wood. 
 
 Decayed Oak. 
 
 Dartmoor 
 Peat. 
 
 Mexican 
 Asphalt. 
 
 Lignite from 
 Bovey. 
 
 Boghead 
 Coal. 
 
 
 Miller. 
 
 Liebig. 
 
 Vaux. 
 
 Regnault. 
 
 Vaux. 
 
 Miller. 
 
 Specific gravity 
 
 81 
 
 
 849 
 
 1-063 
 
 1-129 
 
 1-196 
 
 Coke per cent 
 
 21-3 
 
 
 29-30 
 
 9-0 
 
 30-8 
 
 30-23 
 
 Carbon . 
 
 50-10 
 
 53-47 
 
 54-02 
 
 78-10 
 
 66-31 
 
 63-10 
 
 Hvdrogen 
 
 6-07 
 
 5-19 
 
 6-21 
 
 9-30 
 
 5-62 
 
 8-91 
 
 Nitrogen 
 Oxygen . 
 
 Sulphur . 
 
 t 4368 
 
 \ 41-37 
 
 2-30 
 28-17 
 56 
 
 9'80 
 
 0'56 
 22-86 
 2-36 
 
 } 7-25 
 96 
 
 Ash 
 
 15 
 
 
 9-73 
 
 2-80 
 
 2*27 
 
 19-78 
 
COAL. 
 
 Composition of Coal. 
 
 1031 
 
 
 LesmaJtagow 
 Parrot Coal. 
 
 Wignn 
 Canncl. 
 
 Caking Coal 
 Newcastle. 
 
 \0yard 
 Wolver- 
 hanipton. 
 
 Newport 
 Steam. 
 
 S. Wales 
 Anthracite. 
 
 
 Miller. 
 
 VAUX. 
 
 Richardson. 
 
 Vaux. 
 
 Miller. 
 
 Vaux. 
 
 Specific gravity 
 
 1-251 
 
 1 276 
 
 1-280 
 
 l'/78 
 
 1-309 
 
 1'392 
 
 Coke per cent 
 
 43-3 
 
 (10-36 
 
 
 59-21 
 
 75-10 
 
 92-10 
 
 Carbon . 
 
 73 44 
 
 80'. 7 
 
 86-75 
 
 78-57 
 
 81-47 
 
 90-39 
 
 Hydrogen 
 Nitrogen 
 Oxygen . 
 Sulphur . 
 
 7-62 
 j 11-761 
 
 1-145 
 
 .V.V2 
 2 12 
 8-08 
 1-0 
 
 5-24 
 I 6-61 
 
 5-29 
 1-84 
 
 12-88 
 39 
 
 497 
 1-63 
 5-23 
 1-10 
 
 328 
 
 0-83 
 2-98 
 0-91 
 
 Ash . 
 
 6-034 
 
 2-70 
 
 1-40 
 
 l-(3 
 
 5-51 
 
 1-61 
 
 The composition of coals varies largely, not only in respect of the relative proportions 
 of carbon, hydrogen, oxygen and nitrogen which they contain, but also of the amount 
 of extraneous matters which constitute the impurities of fuel. TLese consist of a vari- 
 able amount of mineral matters which remain after combustion of the coal, as ash or 
 " clinker." 
 
 The percentage of ash ranges from about 1 to 30 or 35, and in some coals, which are 
 considered too poor to be brought to market, to even more than this quantity. 
 
 It consists chiefly of silicate of alumina, with variable amounts of oxide of iron. 
 Vaux found also in many coals traces of lead and copper. 
 
 " We have in nature every gradation, from pure coal into a mere carbonaceous (com- 
 monly called bituminous) shale or ' batt ' which often contains enough imflammable 
 matter to give out flame and support combustion for a time when burnt with better 
 coals, but soon passes into a lump of ash, unaltered in form and not retaining heat 
 longer than a brickbat would under similar circumstances." Accordingly, the compo- 
 sition of the ash of coals closely resembles that of the batts, shales, or fire-clays which 
 usually occur, either as strata above or below the coal, or in their "partings " between 
 the several layers of the coal itself. 
 
 The following table exhibits the amount and composition of the ashes of several coals, 
 as compared with that of fire-clays and " batts " : 
 
 Composition of Coal-ash. 
 
 
 Newcastle 
 coal after 
 deducting 
 Suphuric 
 acid. 
 
 Porous 
 Coal from 
 Zwickau. 
 
 Compact 
 Coal from 
 Zwickau. 
 
 Average 
 of five 
 samples. 
 Welsh. 
 
 Average 
 of five 
 samples. 
 Scotch. 
 
 Blue 
 Shale 
 clay. 
 
 Newcastle 
 Fireclay. 
 
 American 
 Anthracite 
 
 Ash of 
 Bituminous 
 Shale, 
 Bilston, 
 Staffordshire. 
 
 
 
 
 
 
 
 
 Richard- 
 
 
 
 
 Taylor, 
 
 Kremers. 
 
 Kremers. 
 
 Phillips. 
 
 Phillips. 
 
 Taylor. 
 
 son. 
 
 Fawn. 
 
 Wills. 
 
 Silica . 
 
 62-44 
 
 60-23 
 
 45-13 
 
 42-67 
 
 4963 
 
 P8-99 
 
 5708 
 
 54-50 
 
 60-31 
 
 Alumina 
 
 31-22 
 
 31-63 
 
 22-47 
 
 > 
 
 
 26-19 
 
 35-02 
 
 3445 
 
 2985 
 
 Sesquioxide 
 iron . 
 
 2-26 
 
 6'36 
 
 25-83 
 
 43-56 
 
 38-21 
 
 
 5-17 
 
 7-50 
 
 3-14 
 
 Lime 
 
 75 
 
 1-08 
 
 2'80 
 
 6-65 
 
 '3-18 
 
 Fe2O.10-25 
 
 1-63 
 
 2-25 
 
 2-19 
 
 Magnesia 
 
 85 
 
 35 
 
 52 
 
 108 
 
 1'41 
 
 67 
 
 1-73 
 
 1-30 
 
 1-83 
 
 Potash 
 
 2-48 
 
 
 . . 
 
 
 . . 
 
 I'M 
 
 . 
 
 . . 
 
 t 2*12 
 
 Soda 
 
 
 
 24 
 
 
 
 2-34 
 
 
 
 
 Sulphuric 
 
 
 
 
 
 
 
 
 
 
 acid (an- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 4-46 
 
 6-26 
 
 
 
 
 0-69 
 
 Sulphate of 
 
 
 
 
 
 
 
 
 
 
 Calcium . 
 
 
 24 
 
 2-27 
 
 
 
 
 
 
 
 Phosphoric 
 
 
 
 
 
 
 
 
 
 
 acid (an- 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 66 
 
 1-03 
 
 
 
 
 traces. 
 
 Percentage 
 of Ash . 
 
 1-36 
 
 1-74 
 
 1-89 
 
 8-15 
 
 
 
 
 
 
 
 
 Chlorine 0-06 
 
 Muspratt states that the ash of lignite varies from 1 to 60 per cent, averaging about 
 5, and that of bituminous coal 1 to 2 per cent. In addition to these substances, the 
 mineral matter of coal contains a small but variable quantity of sulphur, not accounted 
 for in the above analyses, but constituting a most important element as regards the 
 value of fuel for domestic and technical uses. This remark applies more especially 
 to the value of coals for metallurgical purposes, particularly for employment in the 
 
1032 COAL. 
 
 blast-furnace; the ironmaster, has learned to eschew such samples of ironstone aa 
 contain any considerable percentage of sulphur and phosphoric acid ; but this pre- 
 caution is wholly ineffectual, unless a like care be exercised in the selection of the 
 fuel and fluxes which are to be introduced into the blast-furnace with the ore. 
 
 The presence of sulphur is equally detrimental in the manufacture of gas, some por- 
 tion of it being always eliminated as sulphuretted hydrogen and bisulphide of carbon, 
 the complete removal of which is a matter at once of great difficulty and of the highest 
 necessity, while the frequent cases of spontaneous combustion of coals in the hold of 
 vessels is probably due, in some measure, to the oxidation of the pyrites which they 
 contain under the influence of a moist atmosphere. 
 
 A minor evil is the evolution, during combustion, of sulphurous acid, a gas which is 
 not only noxious and hurtful to human life, but destructive to boilers, locomotive 
 tubes, and so forth. 
 
 Some of the lower seams of the South Staffordshire coal beds, otherwise available as 
 good fuel, are unused, because they contain an amount of sulphur which renders it im- 
 possible to bear the smell which they exhale during combustion ; whence their local 
 name of stinking coal. 
 
 The mean percentage of sulphur found in the government investigation, under 
 Playfair and De la Beche, was as below : 
 
 Samples. Coals. Mean. 
 
 37 ... Welsh 1-42 . 
 
 8 . . Derbyshire 1-01 
 
 28 . . . Lancashire 1-42 
 
 17 . . Newcastle 0'94 
 
 8 ... Scotland 1-45 
 
 The following are other determinations of sulphur in coals : 
 
 4 samples from North Wales, Ruabon -79 
 
 Lignite from Bovey (Vaux) 2*36 
 
 Boghead (Miller) 0-96 
 
 Wigan cannel (Vaux) 1-50 
 
 10 yard Wolverhampton 0'39 
 
 bottom 2'57 
 
 Newport steam coal (Miller) . . . . . . .1*10 
 
 Anthracite, South Wales (Vaux) -91 * 
 
 " The frequent occurrence of iron pyrites in coal shows that its formation at the 
 cost of organic remains is a very frequent phenomenon. This formation of iron pyrites 
 can only be explained by the presence of sulphates ; and so far as it goes on in the sea, 
 only by the decomposition of sulphate of calcium. 
 
 The minor varieties of coal are almost infinite in number, and it is said that full a 
 hundred different kinds are sent into the London market. The following appears to be 
 as satisfactory a classification of the more important kinds as is possible, together with 
 an indication of their characteristic differences, and of the localities whence they are 
 obtained : 
 
 1. LIGNITE or BROWN COAL generally retains in some degree its lamellar and woody 
 structure. Yields a powdery coke in the form of the original lumps. Brittle, burns 
 readily, but often contains from 30 to 40 per cent, water. 
 
 Occurs in England chiefly at Bovey Heathfield, in Devonshire, where it has long 
 been used as fuel in the local potteries ; the supply is now, however, falling off. Its 
 other chief localities are Westphalia, the Hessian States, Lower Austria, Eussia, 
 Spain, Portugal, Italy, the Upper Missouri Valley, New Brunswick (impregnated with 
 copper), Greenland, China, and the Burmese Empire, and in Central America in the 
 province of Panama. 
 
 2. BITUMINOUS or CAKING COALS. The most extensively diffused and valuable of 
 English coals. These are of various shades of brown and black, emit much gas on 
 heating, and hence are prized as " gas-coals ; " they leave a coke more or less lustrous 
 and fused, or caked together. Their fracture is generally uneven and their lustre 
 resinous. The coals of this class are subdivided into : 
 
 Caking Coal, which splinters on heating, but the fragments then fuse together into a 
 semi-pasty mass. Its chief sources are the Newcastle and Wigan districts, along the 
 banks of the Tyne and Wear, and the north of the Tees. 
 
 Cherry Coal or Soft Coal. Lustre very bright. Does not fuse. Ignites well and 
 burns rapidly. Occurs in Glasgow, Staffordshire, Derbyshire, Nottingham, Lanca- 
 shire, &c. 
 
COAL. 1033 
 
 Splint, Hough or Hard Coal. -Black, and of glistening fracture. Does not ignite 
 readily, but burns up to a clear hot fire, constituting a good house coal. Occurs 
 in the Glasgow field, in Shropshire, Leicestershire, "Warwickshire, Derbyshire, and at 
 Nottingham, and constitutes in particular the bulk of the great coalfields of North and 
 South Staffordshire. 
 
 Cannel Coal; Parrot coal of Scotland. Of dense, compact, and even fracture, con- 
 choidal in every direction. Takes a polish like jet. Splinters in the fire and burns 
 clearly and brightly. The chief localities in Great Britain are Wigan, and other parts 
 of Lancashire, West Glasgow, and in smaller quantities at Coventry. It is found also 
 in Kentucky. 
 
 The various kinds of bituminous coal constitute also the bulk of the immense coal- 
 fields of North America, compared with which the most extensive fields of the Old 
 World are insignificant. These are the Alleghany or Appalachian field, and those of 
 Pennsylvania, Illinois, New Brunswick, and Nova Scotia. In South America they 
 occur in the province of Chili. They compose also the south side of the South Wales 
 basin ; are found in Connaught and Ulster, and on the European continent in Belgium, 
 France, Prussia, Sweden, Russia, and Spain. Finally, the great coal range of New 
 South Wales is supposed to belong to this class. 
 
 4. ANTHRACITE. STONE-COAL or CULM. The densest, hardest, and most lustrous 
 of all varieties. Burns with very little flame or smoke, but gives great heat. Con- 
 tains very little volatile matter. Splinters when heated, and ignites with difficulty. 
 Colour deep black, fracture lamellar, parallel to the bed of the deposit, conchoidal in 
 the cross fracture. Applied successfully to smelting, and much valued as a steam coal 
 in the navy. Its most extensive deposit occurs over vast tracts of North America, 
 chiefly in Pennsylvania. It constitutes also a large portion of the yield of the north- 
 west portion of the South Wales coalfield. A further deposit occurs over a tract of 
 about 12^ miles in Devonshire, in the neighbourhood of Barnstaple Bay and Bideford. 
 Its other situations are Leinster andMunster in Ireland, and some districts of France, 
 Sweden, and Portugal. 
 
 5. STEAM COAL approaches nearly to anthracite. It does not crumble into small 
 pieces under friction, and is hence well adapted for stowage. It also emits little 
 smoke, a point of great importance in naval warfare, where the smoke of ordinary coals 
 would reveal the position of vessels to a distant enemy. Its chief locality is the 
 north-west of the South Wales basin and the north of the Tyne and Blyth district. 
 
 In addition to the above-named varieties, we must mention the remarkable deposit of 
 Bathgate, near Edinburgh, commonly known as the " Torbane hill mineral or Boghead 
 cannel coal," respecting which a curious lawsuit arose upon the question whether or 
 not the substance was to be considered as " coal." It is of a dull brown colour in the 
 upper part, and black in the lower part of the seam, and of low specific gravity. It 
 contains about 20 per cent, of aluminous ash, which remains after ignition in the 
 form of the original lump, retaining 6 to 10 per cent of carbon. About 70 per cent., 
 therefore, consists of volatile matter, whence the great value of the mineral for two pur- 
 poses ; 1st for gas making; 2nd for distillation, by Young's process, in close vessels at 
 a low temperature, whereby a large number of liquid hydrocarbons of various densities 
 and boiling points are obtained, fit respectively for illuminating and lubricating pur- 
 poses, together with paraffin and other solid products. 
 
 The analyses already given fairly represent the ordinary composition of the several 
 classes of coals. 
 
 Valuation of Coal. A. ready method of accurately estimating the general value of 
 coal as fuel is yet a desideratum. Its elementary analysis affords the means of cal- 
 culating its theoretical heating power ; but it is found in practice that th* amount of 
 work indicated by this result can never be obtained, and further that the condition of 
 mechanical division, draught of furnaces, and many other extraneous circumstances 
 affect the result so largely, that the actual work obtained seldom bears any palpable 
 relation to the theoretical indication. 
 
 The weight of water in pounds raised one degree in temperature by the combustion 
 of 1 cubic inch of each of a large number of combustible substances, and also by such 
 a weight of each as combines with 1 cubic inch of oxygen, has been determined by 
 the direct experiments of Lavoisier, Laplace, Despretz, Dulong, Rumford, Regnault, 
 Andrews, and others, the general principle of their methods consisting in the use of 
 an apparatus wherein the entire heat of combustion was absorbed by a known weight 
 of water, the whole arrangement being protected from the influence of external changes 
 of temperature, and the increase of temperature of the water being known by the 
 simultaneous indication of several delicate thermometers suspended in it. (See HEAT.) 
 
 The method of Berthier, though only approximative, affords useful indications when 
 
1034 COAL. 
 
 applied, with certain precautions, to various samples of the same class of coal or from 
 the same mine. 
 
 It is based upon the reduction of oxide of lead by the carbon and hydrogen of the 
 fuel, in fact the combustion of the coal at the expense of the oxygen of litharge, the 
 weight of metal produced indicating the amount of oxygen expended, whence the heating 
 power may be calculated. It is found that 1 pt. of pure carbon produces 34-5 of me- 
 tallic lead ; hence if a sample of fuel produces 25, the heating power is - of that 
 
 of carbon, or assuming that 1 Ib. of carbon raises 7900 Ibs. of water 1, 1 Ib. of the 
 sample of coal is capable of raising 5724 Ibs. of water by 1. 
 
 Various tables have been given by Berthier and other experimenters, of results ob- 
 tained in this manner, the following being some of the most useful figures : 
 
 Coking Dowlais coal produces 31 '8 Ibs. lead 
 
 Glamorgan 31 '2 
 
 Newcastle , 30'9 
 
 Wigan cannel , 28'3 
 
 Cherry coal, Derbyshire , 27 '2 
 
 Glasgow cannel , 24'9 
 
 Durham , 31 '6 
 
 Pennsylvanian anthracite , 30'5 
 
 By a comparison of the result of any experiment with these standard figures, a 
 tolerably fair estimate may be made of the spec fie value of any sample. 
 
 The method of operating consists simply in mixing a known weight of the finely 
 powdered fuel with about forty times its weight of pure litharge, and exposing the 
 mixture to a gentle heat in a large crucible finally raised to a clear red heat. The pot 
 is removed, struck on the floor to assist the settling of the metal, and broken when 
 cold. The button is cleaned and weighed. The accuracy of the result depends greatly 
 upon the relative proportion of hydrogen and oxygen : when they are in the propor- 
 tion necessary to form water, the result is tolerably correct ; but it is evident that any 
 excess of hydrogen over and above this proportion introduces an error, inasmuch as its 
 h^at equivalent is calculated as if it were carbon, while in truth it is about four times 
 as great. The results of the British Admiralty investigation, by De la Beche and 
 Playfair, exhibit a variation often "amounting even to a virtual contradiction" of the 
 simultaneous results of direct combustion. 
 
 Other experimenters have found difficulty in obtaining constant results by Berthier's 
 method, but Mitchell has found that the difficulty may be obviated by substituting 
 ordinary carbonate of lead for the litharge. 
 
 The best practical method of valuing fuel consists in employing an apparatus 
 similar to those used by Andrews and other chemists in the determination of the 
 actual heating power of carbon, hydrogen, &c., or of a miniature furnace to which a 
 known volume of air is supplied, with arrangements, such as readily suggest them- 
 selves, for the complete utilisation of the heat evolved. It is to be remembered that 
 the real value of all such results is simply relative. 
 
 The imperfect character of most boiler arrangements and the large quantity of coal 
 which passes into the ash-pit unconsumed, together with the irregular supply of draught 
 and the amount of heat absorbed by the great excess of cold air, result practically in 
 an enormous loss of heating power, to an extent which, even under the most careful 
 management, is widely variable. Thus, the results obtained in the American and 
 British Admiralty experiments exhibit grave discrepancies. In the case of the latter 
 investigation, a Cornish boiler only 12 feet long was employed, and "even from the 
 smallness of the boiler emphryed, the results fell short by 20 per cent, of the maximum 
 amount of work which the same fuels could perform when applied to larger boilers con- 
 structed and set on the same principle. The inquiry is rendered less efficient from 
 another cause, viz. the want of a thorough control and measurement of the air passing 
 through the furnace." 
 
 "We have referred to the injurious properties of sulphur as an ingredient in coals, 
 and to its average quantity in various classes of fuel. Its amount may be estimated 
 by fusing in a large silver capsule a few pieces of caustic potash and | of its weight 
 of nitrate of potash and a few drops of water. After cooling, the finely powdered 
 coal is added, and the whole re-fused till white. The mass is dissolved in hydro- 
 chloric acid, and the sulphuric acid produced is estimated by precipitation with 
 chloride of barium. It is always necessary at the same time to estimate the quantity 
 of sulphuric acid present in the ash of the coal, and to deduct this from the amount 
 obtained as above, in order to obtain the quantity due to the oxidation of the sulphur 
 only. 
 
COAL-GAS. 
 
 1035 
 
 Deflagration with 2 pts. nitre and 10 of chloride of sodium may also be employed, 
 but the greatest care is necessary to control the action. 
 
 The importance, in addition to a knowledge of the chemical character of a fuel, of a 
 consideration of its mechanical condition, is amply exhibited by the fact acknowledged 
 in both the government series of experiments, that it was a sine qua non that the 
 toughness of coals must be such, for naval use, as to resist, without crumbling, the 
 constant friction in the ship's hold, at the same time that its fracture must be such 
 that it packs into the smallest possible space. In this respect, coals of equal heating 
 power vary 20 per cent, at least. " This factor, which is of extreme importance in steam- 
 navigation, becomes reduced the more the cleavage of the coal or the shape of the fuel 
 approaches the form of a cube. In -order to attain, at least, a relative idea of the 
 waste occasioned by transport, i. e. of the attrition of the individual pieces of coal 
 against each other, and conversion of unbroken coal into dust unfit for use, which is 
 occasioned by the motion of the vessel, the various specimens were rotated in a drum 
 for the samelength of time, and the dust thus produced separated and weighed." 
 
 The subjoined table shows some of the results of the British investigation as regards : 
 
 1. Number of Ibs. of water at 100 C. converted into steam by 1 Ib. of fuel. 
 
 2. Ditto, after deducting portions of coke contained in the ash. 
 
 3. Theoretical evaporative power in Ibs. of water of 100 C. evaporated by lib. of 
 
 fuel calculated from litharge test. 
 
 4. Weight of coal per cubic foot of stowage in Ibs. 
 
 5. Ditto, per solid cubic foot, deduced from specific gravity. 
 
 6. Percentage loss by equal amount of attrition. 
 
 Kind of Fuel. 
 
 1. 
 
 2. 
 
 3. 
 
 4. 
 
 5. 
 
 6. 
 
 WELSH: 
 Jones and Co's Anthracite .... 
 
 9-46 
 9-40 
 
 970 
 10'fiO 
 
 13-84 
 16-40 
 
 58-25 
 57' 4 3 
 
 85-79 
 83 8 i 
 
 685 
 46'** 
 
 
 9-35 
 
 Q-66 
 
 16'72 
 
 60" 17 
 
 81*11 
 
 49'3 
 
 
 10-14 
 
 11-80 
 
 15*64 
 
 53-22 
 
 82'7'2 
 
 *^6*2 
 
 
 7*47 
 
 8'04 
 
 14-31 
 
 55*70 
 
 82-85 
 
 57*5 
 
 Ebbw Vale 
 
 10-21 
 
 10-61 
 
 16 - 6S 
 
 53 30 
 
 78" 81 
 
 
 
 9*79 
 
 9'99 
 
 14"70 
 
 50-50 
 
 82 GO 
 
 fj ( Q 
 
 SCOTCH : 
 Dalkeith Jewel 
 
 7'08 
 
 7-10 
 
 13'77 
 
 49 80 
 
 
 
 Wallsend Elgin 
 
 8*46 
 
 8*67 
 
 
 5 4. (50 
 
 
 
 Fordel Splint . . . 
 
 7*56 
 
 7*69 
 
 
 5VOO 
 
 
 
 
 7.40 
 
 7'91 
 
 14-85 
 
 54 25 
 
 
 
 ENGLISH: 
 
 7-30 
 
 7*66 
 
 13'20 
 
 52' 50 
 
 
 
 Park End Sydney 
 
 8 '52 
 
 8*98 
 
 
 
 
 
 IRISH: 
 Slieverda^h ...... 
 
 9*85 
 
 10*49 
 
 16*21 
 
 62'80 
 
 
 
 Mean of three patent fuels .... 
 
 9-27 
 
 9-66 
 
 15-44 
 
 66*48 
 
 70-6'i 
 
 
 For further information on coal, see Ure's Dictionary of Arts, Manufactures and 
 Mines, i. 696 ; also Ronalds and Richardson's Chemical Technology, 2nd ed. i. [1] 28; 
 i. [2] 761 ; Percy's Metallurgy, i. 78106. W. W. 
 
 CO AXi-GAS. The gas produced by the destructive distillation of pit-coal at regu- 
 lated temperatures. 
 
 The apparatus used in the manufacture of coal-gas on the great scale consists essen- 
 tially of a system of closed retorts of fireclay or cast-iron, the exit pipes from which 
 communicate with a hydraulic main, in which the crude gas deposits part of its tar 
 and ammoniacal products. It passes thence into a series of condensing pipes, wherein 
 it is exposed to the action of a large refrigerating surface, and deposits the greater 
 part of its tar and ammonia-liquor, the last portions being removed in its passage 
 through another series of vessels of various forms and modifications, in which the 
 gas is scrubbed, by being obliged to force its way through breese, stones, or other mate- 
 rials which serve to comminute it and bring it into thorough contact with a stream of 
 water which continually percolates the vessel. It is then deprived of its carbonic acid 
 and sulphuretted hydrogen in lime purifiers, and finally is drawn by exhausting appa- 
 ratus into the gas-holders, passing on its way through the station-meter and other 
 beautiful and delicate apparatus, whereby the pressure and amount of gas which 
 passes into the town are regulated and registered. (See the article COAL-GAS in Ure's 
 Dictionary of Arts, Manufactured and Mines.} 
 
1036 
 
 COAL-GAS. 
 
 The following analysis by Bunsen and Koscoe exhibits the composition of Man- 
 chester coal-gas prepared from Cannel coal : 
 
 Hydrogen .......... 45'58 
 
 Marsh-gas . . 84'90 
 
 Carbonic oxide 6'64 
 
 Olefiant gas or ethylene 4-08 
 
 Tetrylene 2'38 
 
 Sulphuretted hydrogen 0-29 
 
 Nitrogen , 2*46 
 
 Carbonic acid . . . . . . . . . 3-67 
 
 100-00 
 
 In addition to these constituents, there are frequently present traces of ammonia, 
 vapour of sulphide of carbon, cyanogen, and oxygen. 
 
 The composition above given, represents that of a first-rate sample of gas ; but the 
 relative proportion of the several ingredients depends both upon the quality of coal 
 used, upon the temperature of the retorts, and the time during which the distillation 
 is continued. It is to the olefiant gas and other heavy hydrocarbons present in com- 
 paratively small quantities, that the illuminating power of gas is chiefly due ; the 
 maintenance of a full proportion of this gas is therefore of the utmost importance. 
 The following table shows the quality of gas from 1120 Ibs. of common coal at the 
 Clifton gas-works, Manchester, at different periods of distillation : 
 
 
 100 measures purified gas contain 
 
 100 measures of purified 
 
 mencement. 
 
 
 
 
 
 
 Olefiant gas. 
 
 Nitrogen. 
 
 Other inferior gases. 
 
 Oxygen. 
 
 1 
 
 10 
 
 
 
 90 
 
 164 
 
 3 
 
 9 
 
 
 
 91 
 
 168 
 
 6 
 
 6 
 
 
 
 94 
 
 1 132 
 
 7 
 
 5 
 
 15 
 
 80 
 
 120 
 
 9 
 
 2 
 
 9 
 
 89 
 
 112 
 
 11 
 
 
 
 15 
 
 85 
 
 90 
 
 Hence, two things should especially be avoided in the manufacture of gas, viz. 
 too low a heat and a too long continuation of the distillatory process. The effect of 
 too low a heat is a great diminution of the gaseous products, the chief result of the 
 distillation being the production of tar. The effect of continuing the distillation too 
 long, is that gases of very feeble illuminating power are evolved, together with nitrogen, 
 which, when once mingled with the combustible gas, cannot be removed by any known 
 method, and must seriously impair its illuminating power. 
 
 The following table by Hughes gives an idea of the relative and absolute yield of 
 different kinds of coal under practical management : 
 
 Name of Coal. 
 
 Cubic feet of 
 Gas per ton. 
 
 Specific Gra- 
 vity of Gas. 
 
 Weight of Gas in Ibs. 
 per ton of Coal. 
 
 Newcastle, average of 3 samp. 
 
 11,492 
 
 452 
 
 398 Hedley. 
 
 ,. 10 
 
 11,336 
 
 416 
 
 362 Clegg. 
 
 Wigan cannel 
 
 9,500 
 
 490 
 
 357 Fyfe. 
 
 * 
 
 9,408 
 
 478 
 
 344 Wright. 
 
 Scotch Parrot . 
 
 9,500 
 
 640 
 
 466 
 
 Lesmahago cannel 
 
 11,312 
 
 737 
 
 638 Hedley. 
 
 Boghead cannel . 
 
 15,000 
 
 752 
 
 866 Evans. 
 
 Ince Hall cannel 
 
 11,400 
 
 528 
 
 461 
 
 Derbyshire . 
 
 9,400 
 
 424 
 
 308 Wright. 
 
 soft, aver, of 3 samp 
 
 7,166 
 
 466 
 
 256 Parliamentary return. 
 
 Neath, South Wales . 
 
 11,200 
 
 468 
 
 401 Hedley 
 
 Westbromwich, parliament- 
 
 
 
 
 ary return of Birmingham 
 
 
 
 
 gas company . 
 
 6,500 
 
 453 
 
 226 
 
 Staffordshire, average of 4 
 
 
 
 
 samples .... 
 
 10,467 
 
 376 
 
 302 Clegg. 
 
COAL-GAS. 1037 
 
 Modes of estimating Luminiferous Value. 
 
 The gas manufacturer relies much as an indication of the purity of his gas, upon its 
 specific gravity, which he commonly takes approximately by means of a balloon, con- 
 taining when full 1000 cubic inches, and gauged by a ring which fits its largest diameter 
 when full. Attached to the balloon is a car, into which as many grains are put as balance 
 the balloon. This result, although not scientifically accurate, gives, after correction for 
 temperature, barometer, &c., an indication of sufficient practical value, but of course 
 vitiated by the presence of any large amount of carbonic acid. 
 
 The comparison of gases by the photometer is a test preferred by many gas-engineers 
 to all others. It consists of the comparison either of shadows, or of transmitted light 
 passing through a semi-transparent disc of paper with reflected light striking on an 
 opaque portion, in juxtaposition to the transparent portion. When the light is so ad- 
 justed that the shadows are precisely similar, or that the light reflected and that 
 transmitted by the disc are equal, then the lights are to each other in the ratio of the 
 squares of their distance from the disc or screen. 
 
 The only chemical test upon which the practical gas maker commonly relies, is the 
 amount of absorption which takes place upon introducing into a known volume of gas 
 a bubble of chlorine or a drop of bromine, tlie principal hydrocarbons to which gas 
 owes its luminiferous value being condensed by these reagents into oily compounds. 
 These methods are, however, of the roughest kind. 
 
 An accurate result may, however, be obtained by substituting for chlorine or bromine 
 a fragment of coke saturated with Nordhausen sulphuric acid, the experiment being 
 made over mercury and the absorption being allowed to go on for two or three hours. 
 Subsequently the sulphurous acid produced in this action is removed by a ball of bin- 
 oxide of manganese, and finally aqueous vapour is removed by a ball of caustic potash. 
 The quantity of carbonic acid being also determined, the difference between the two 
 experiments gives the amount of luminiferous hydrocarbons accurately. The value of 
 these, being in proportion to the carbon they contain, is ascertained by exploding 
 portions of gas before and after removal of the hydrocarbons with excess of oxygen, and 
 comparison of the amount of carbonic acid produced in each case respectively. The 
 difference is the amount due to the carbon of the luminiferous constituents. (For 
 details of the mode of analysis of such a mixture, we refer to Miller's Chemistry, ii. 
 661, to Regnaults Cours Elementaire, iv. 73, to Clegg's Treatise on Coal- gas, and 
 more particularly, for the most recent and accurate methods of operation, to Bunsen's 
 Gasometry, p. 107, to the article ANALYSIS (VOLUMETBIC) OF GASES, in this Dictionary, 
 and to the article COAL-GAS in the new edition of Ure's Dictionary of Arts, Manufac- 
 tures and Minex.') 
 
 The Eev. W. B. Bowditch proposes to determine the relative illuminating power of 
 coal-gas, in other words, the proportion of ethylene, propylene, and other heavy hydro- 
 carbons contained in it, by the intensity of the red colour which they impart to woody 
 fibre moistened with sulphuric acid. When rich coal-gas, giving the light of 20 to 25 
 sperm candles from consumption of 5 ft. per hour, is slowly passed through clean deal 
 sawdust, well moistened with pure sulphuric acid diluted with five or six volumes of 
 water, so that it may not blacken the sawdust, that substance instantly acquires a 
 beautiful pink colour, which gradually deepens to a dark mahogany; with a poor 
 gas, which gives the light of only ten or twelve candles at the same rate of consumption, 
 the coloration is faint at first and deepens very slowly. The differences of coloration 
 are so considerable and constant that they may perhaps be used as a means of deter- 
 mining the illuminating value of the gas. By using a standard acid, the same kind 
 of sawdust, a uniform volume of gas, and the same sized U-tubes, notation of time and 
 depth of colour would give a close approximation to the light-giving value. (Proc. 
 Koy. Soc. xi. 25.) 
 
 In addition to the constituents estimated by these operations, it is frequently im- 
 portant to determine sulphuretted hydrogen and bisulphide of carbon. Their presence 
 is well detected by the simple and useful apparatus of Wright, consisting of an ar- 
 rangement for condensing the products of combustion from a gas-jet, and testing the 
 condensed liquid for sulphuric acid. 
 
 Their amount may be determined by passing a known volume of gas through, 1st, a 
 solution of caustic potash in water, and, 2nd, a solution of the same reagent in alcohol. 
 The former absorbs sulphuretted hydrogen ; the latter the sulphide of carbon, which 
 it converts into xanthate of potassium, which is in turn decomposed by boiling. Dilute 
 solution of nitrate or acetate of lead being added, sulphide of lead is precipitated, and 
 its amount is judged of by comparison of the shade of colour produced in the liquid 
 with a solution containing a known quantity of lead precipitated in the like form. 
 
 Another method of detecting sulphide of carbon in coal-gas, is to pass it through an 
 ethereal solution of tritthylphospkinc, which forms with sulphide of carbon a compound 
 
1038 COAL-GAS. 
 
 crystallising in splendid ruby-red prisms (Uofmann, Chem. Soc. Qn. J. xiii. 87). 
 This is a much more delicate test than the preceding. Hofmann found that, on pass- 
 ing a current of coal-gas through a solution of four or five drops of triethylphoephine 
 in ether contained in a bulb-apparatus, a distinct red coloration was produced after 
 0'2 of a cubic foot of gas had passed through the liquid; and after 0'8 of a cubic foot 
 had passed, the whole of the ether had evaporated, and the inner surface of the bulb- 
 apparatus was lined with a beautiful net-work of the ruby crystals. 
 
 Lastly, the sulphide of carbon may be easily detected by a method which likewise 
 serves for its removal. For this method we are indebted to the Eev. W. E. Bow- 
 ditch (loc. tit.} It consists in decomposing the sulphide of carbon with hydrogen, 
 thereby converting it into sulphide of hydrogen, which is easily detected and removed 
 by the usual methods. "When a mixture of hydrogen and vapour of sulphide of carbon 
 is passed through a tube filled with slaked lime or clay, which has been dried between 
 400 and 500 Fahr., and is kept between 400 and 600 during the passage of the 
 gaseous mixture, the sulphide of carbon is completely decomposed, the lime or clay is 
 blackened by a deposit of carbon, and sulphur sublimes in the exit-tube, while sulphide 
 of hydrogen passes through, and may be detected by acetate of lead. The same effect 
 is produced when coal-gas containing sulphide of carbon is passed over heated lime or 
 clay, the free hydrogen in the gas then decomposing the sulphide of carbon in the 
 manner just described. This method may be applied on the large scale to the puri- 
 fication of coal-gas from sulphide of carbon, the sulphuretted hydrogen resulting from 
 the decomposition being afterwards removed by slaked lime in the ordinary way. 
 Passing the gas over clay likewise decomposes other volatile sulphur-compounds which 
 are not removed by the ordinary mode of purification with lime. These compounds, 
 including sulphide of carbon, have long been regarded as the most troublesome im- 
 purities of coal-gas. The sulphur which is evolved from the coal as sulphuretted hy- 
 drogen, is easily removed by slaked lime ; indeed, the London coal-gas rarely, if ever, 
 exhibits the slightest trace of this compound. But it always contains sulphide of 
 carbon or some of the other volatile sulphur-compounds just mentioned, the proportion 
 of sulphur contained in it varying, according to Hofmann (loc. tit.), from 6'68 to 10*33 
 grains in 100 cubic feet. Now the sulphur in burning produces sulphurous acid, which, 
 besides being offensive to the senses, is very destructive to art-decorations, bindings of 
 books, &c. The removal of these sulphur-compounds will, therefore, do away with 
 the greatest existing objection to the use of gas in dwelling houses. 
 
 The use of clay as a purifier of coal-gas is likewise attended with other advantages, 
 as it absorbs ammonia and other nitrogen-compounds which diminish the light-giving 
 power of the gas. This effect is especially conspicuous when the gas given off to- 
 wards the end of the distillation (p. 1036), is submitted to the action of the clay. 
 
 Clay which has become charged with the impurities from coal-gas, may afterwards 
 be used as a manure. 
 
 Secondary Products obtained in the manufacture of Coal-gas. 
 
 After a charge of coal has been worked off to the extent considered most desirable, 
 the man-lids are removed from the retorts, and the residual coke raked out into barrows, 
 wheeled away and quenched with a jet of water. Its appearance and uses, as fuel for 
 locomotives, in the blast furnace, and in a vast number of technical operations, are too 
 well known to need description, nor does space allow us to go into details of the 
 numerous processes which have been employed, with more or less success, for the 
 economical preparation and purification of coke. 
 
 The liquids condensed during the passage of the gas through the hydraulic mains 
 and condensers, are of a very complex character. They consist ^essentially of two 
 portions, the one watery and the other tarry, crude coal-tar varying in density between 
 1120 and 1150, the lightest portions containing the largest proportion of liquid oils. 
 
 The basic substances contained in coal-tar include ammonia, aniline, picoline, 
 chinoline, pyridine, toluidine, and others of less importance. 
 
 The acids include acetic in minute quantities, rosolic, brunolic, &c., but principally 
 phonic or carbolic acid. The neutral portions contain benzene, toluene, cumene. cymene 
 (liquids) ; naphthalene, paranaphthalene or anthracene, chrysene, and pyrene (solids). 
 
 The commercial distillation of coal-tar is performed in large retorts, holding from 
 200 to 500 gallons. The first products are gaseous ; next passes water charged with 
 ammoniacal salts, and contaminated with black oily matter. 
 
 The proportion of oil continues to increase, while that of watery products diminishes. 
 Finally, after from 5 to 10 per cent, of the whole has passed in the form of " light oil," 
 the product becomes heavier than water, and is collected apart as "kreasote oil," or 
 "dead oil" used extensively for the pickling or antiseptic preparation of timber, and 
 for burning into lamp-black. Naphthalene and other solid products now become abun- 
 dant and the oil becomes pasty. Finally, the residue in the retort is run off while hot, 
 
COBALT. 1039 
 
 and on cooling becomes hard and brittle, constituting asphalt, a product used in the 
 manufacture of coarse varnishes, and on a vastly larger scale in laying down railway 
 and other bridges, as a means of protecting their masonry from the infiltration of water. 
 
 The heavy oil contains a variety of hydrocarbons of high boiling point, together 
 with carbolic acid, to which latter it probably owes its antiseptic qualities. 
 
 The light oils obtained in the above process are rectified, whereby a further portion of 
 heavy oils is separated and crude naphtha obtained. This is agitated with sulphuric 
 acid, and the supernatant liquid, upon careful rectification, yields the " highly rectified 
 naphtha" or "benzole" of commerce, consisting of a complex mixture of at least 
 five oils boiling at from 149 to 392 F., and of specific gravity '860 to -890. 
 
 The watery liquids deposited in the condenser during the manufacture of gas, are 
 devoted to the production of sulphate and chloride of ammonium. They are usually 
 removed from the gas-works in flats or canal boats of known capacity, under contracts 
 commonly taken at so much per 10,000 gallons. 
 
 The manufacture of chloride of ammonium direct from the liquors, is conducted on 
 a large scale in Liverpool, and consists essentially in saturating with hydrochloric 
 acid, concentrating the liquors, crystallising and subsequently subliming the crystals. 
 A far larger portion, however, of the crude gas-liquor is consumed in the manufacture 
 of sulphate of ammonium, by processes which consist essentially of distillation, with 
 addition of lime, to decompose ammoniacal salts, and condensation of the vapour in 
 sulphuric acid, concentration and crystallisation of the solution after saturation has 
 been effected. Sulphate of ammonium is employed in large quantities in the manu- 
 facture of artificial manures. 
 
 The above are the chief products of distillation of coal at high temperatures, while 
 those at regulated low temperatures are far different. Under the latter conditions, 
 the gaseous products are reduced to their minimum, while the quantity of liquid and 
 solid hydrocarbons is proportionately increased. 
 
 The Boghead Cannel of Bathgate, near Edinburgh, is extensively submitted to the 
 process of slow destructive distillation, under the patent of Young, while successful 
 efforts have lately been made by Mr. Blackwell, of Dudley, to turn to account the vast 
 heaps of somewhat bituminiferous shales or " batts " ejected from the coal mines of 
 Staffordshire. 
 
 To this subject we cannot further refer than to remark that for practical purposes 
 the products may be separated into three portions. 
 
 1. Eemains liquid at all ordinary temperatures and forms, after proper purification, 
 a valuable burning oil, known as " photogen." 2. Deposits crystals of solid hydro- 
 carbons at very low temperatures ; used extensively for lubricating machinery and 
 known as " paraffin oil." 3. Solid or semi-solid products, which when freed from the 
 oils which contaminate them by pressure, &c. consist chiefly of paraffin (q. v.) and may 
 be employed alone or mixed with tallow, stearin, &c. in the manufacture of candles. 
 
 W. W. 
 
 COBALT. Kobalt, Cobaltum. Symbol, Co. Atomic Weight, 29'5. The use of 
 cobalt for imparting a blue colour to glass, appears to have been known to the Greeks 
 and Komans, though most of their blue glasses were coloured with copper. Some of 
 the pigments used by the ancient Greeks likewise contained cobalt. The use of cobalt 
 for the preparation of smalt was introduced about the middle of the sixteenth century. 
 The metal, in an impure state, was first extracted by Brandt in 1733. 
 
 Cobalt is not a very abundant metal. It occurs as an arsenide, called tin-white cobalt 
 or smaltine; as sulpharsenate, or cobalt-glance; as arsenate, or cobalt-bloom; as sul- 
 phate and as black earthy cobalt, which is a compound of protoxide of cobalt with per- 
 oxide of manganese. It also occurs in small quantity in other minerals as in selenide 
 of lead, cerite, and Flemish coal. In the metallic state, it occurs only in meteorites, 
 many of which contain from 01 to 1 per cent, of it, associated with iron and nickel. 
 
 Preparation. Cobalt is extracted chiefly from smaltine and cobalt-glance, or from 
 the impure arsenate obtained by roasting these ores. The roasting has the effect of 
 driving off a considerable portion of the arsenic, which escapes as arsenious oxide, and 
 is condensed in the manner described under ARSENIC (i. 365). The roasted product 
 consists essentially of basic arsenite, arsenate and sulphate of cobalt, together with 
 iron, nickel, and in smaller quantity bismuth, tin, copper, and manganese. When 
 prepared on the large scale, it is mixed with twice its weight of siliceous sand, and 
 sent into the market under the name of zaffrc, which is used for giving a blue colour 
 to glass, enamels, and pottery glaze. 
 
 The preparation of a pure oxide of cobalt from the native minerals or the roasted 
 ore, is effected by one of the following processes : 
 
 1. Cobalt or smaltine is dissolved in nitric acid, or in dilute sulphuric or hydro- 
 chloric acid, to which a little nitric acid is added, or the roasted ore or earthy 
 cobalt is dissolved in sulphuric or hydrochloric acid alone ; the filtered solution is 
 
1040 COBALT. 
 
 evaporated nearly to dryness, a large quantity of arsenious acid then separating out ; 
 and the liquid is largely diluted, separated from the arsenious acid, and treated with 
 sulphuretted hydrogen as long as the sulphides of arsenic, copper, and bismuth (to- 
 gether with tin) continue to be precipitated. The solution is then filtered, and heated 
 till the excess of sulphuretted hydrogen is expelled and the protoxide of iron con- 
 verted into sesquioxide ; carbonate of sodium is then added in excess, while the liquor 
 is hot, to precipitate the nickel and cobalt in the form of carbonates, and the iron as 
 sesquioxide. The precipitate is then well washed and digested with excess of aqueous 
 oxalic acid ; the soluble ferric oxalate is separated by filtration from the oxalates of 
 nickel and cobalt, which are insoluble even in excess of oxalic acid ; and the latter 
 salts are triturated with dilute ammonia (it should be strong ammonia according to 
 Stromeyer) and dissolved in excess of the ammonia, by agitation and gentle heating 
 in a close vessel. The filtered solution, after exposure to the air for several days, 
 deposits the oxide of nickel in combination with oxalic acid and a small quantity of 
 ammonia, while pure oxalate of cobalt remains in solution. (The oxalate of nickel 
 separated as above may be freed from the small quantity of cobalt-salt which falls 
 down with it, by washing with water, re-dissolving in ammonia, exposing the liquid 
 to the air, and separating the solution which contains the cobalt from the nickel pre- 
 cipitate, the purity of which, increases at each repetition of the process.) The residue 
 obtained by evaporating the ammoniacal solution of the oxalate, yields sesquioxide of 
 cobalt when ignited in the air, and metallic cobalt if ignited out of contact of air. 
 (Laugier.) 
 
 2. To avoid the tedious passing of sulphuretted hydrogen through the liquid, the 
 arsenic acid may be precipitated by first mixing the dilute solution with a ferric salt, 
 and then adding carbonate of potassium in small successive portions and with constant 
 agitation, as long as the precipitate continues to exhibit a white or brownish colour 
 (arsenate of ferric oxide) ; till, in short, a filtered sample of the liquid gives a reddish 
 precipitate with a small quantity of carbonate of potassium. If the quantity of ferric 
 oxide be sufficient, and the proportion of carbonate of potassium rightly adjusted, the 
 whole of the arsenic acid and ferric oxide may be precipitated. If the copper and 
 bismuth be then removed by sulphuretted hydrogen, it only remains to separate the 
 nickel from the cobalt. (Berthier.) 
 
 3. Finely powdered cobalt-ore is carefully roasted, and 1 pt. of it added in suc- 
 cessive small portions to 3 pts. of acid sulphate of potassium heated to the melting 
 point in an earthen or cast-iron crucible. The mass, which is thereby rendered pasty, 
 is then more strongly heated till it fuses quietly and no longer gives off fumes of 
 sulphuric acid, as it is necessary to drive away the excess of that acid. The mass, 
 while yet liquid, is then taken out of the crucible with an iron spoon broken to 
 pieces after cooling dissolved in boiling water, and filtered from the arsenates of 
 iron and cobalt, which are not soluble in a neutral liquid. Sulphuretted hydrogen is 
 then passed through the filtrate to throw down any antimony, bismuth, or copper that 
 may be present the liquid again filtered, and pure carbonate of cobalt precipitated by 
 carbonate of potassium. To prevent the formation of arsenate of cobalt, the roasted 
 cobalt-ore, before fusion with sulphate of potassium, may be mixed with a small 
 quantity of ferrous sulphate, so that the arsenic acid may combine with the oxide of 
 iron contained in that salt in preference to the oxide of cobalt. No nickel is taken 
 up by the liquid, because the sulphate of nickel is decomposed at a red heat [not so, 
 however, the sulphate of nickel and potassium, unless the heat applied is very strong]. 
 The solution retains but a trace of iron at the utmost. (Liebig, Pogg. Ann. xviii, 164.) 
 
 4. One part of pulverised smaltine or cobalt-glance is fused in a covered earthen 
 crucible with 3 pts. of carbonate of potassium and 3 pts. of sulphur, whereby the 
 whole of the metals present are converted into sulphides, and sulphide of potassium is 
 formed, which unites with the sulphide of arsenic, forming a soluble sulpharsenate. 
 The heat must be so regulated that the sulphide of cobalt may not fuse, but remain in the 
 form of a crystalline powder, because, if fusion takes place, portions of the sulpharsenate 
 of potassium will be enclosed in the fused mass, and will be difficult to wash out. The 
 mass is then freed from sulpharsenate of potassium by repeated exhaustion with water 
 and decantation ; again treated with carbonate of potassium and sulphur, and then with 
 water to remove the rest of the arsenic; afterwards dissolved in nitric acid or in 
 dilute sulphuric acid mixed with nitric ; the solution is treated with sulphuretted 
 hydrogen to remove any remaining arsenic, together with bismuth and copper ; and the 
 filtered liquid is treated as in method b, to separate the cobalt from nickel and iron. 
 (Wohler, Pogg. Ann. vi. 277.) 
 
 5. To obtain cobalt from black earthy cobalt ore, the mineral is dissolved in hydro- 
 chloric acid ; the arsenic, antimony, lead, and copper are precipitated by sulphuretted 
 hydrogen ; the filtrate is boiled with nitric acid to promote the further oxidation of 
 the iron ; the iron is precipitated by boiling with acetate of sodium, and the cobalt 
 separated from the filtrate by sulphuretted hydrogen, which leaves acetate of manga- 
 
COBALT: ALLOYS. 1041 
 
 nese undecomposed. The precipitate is free from nickel, but contains a trace of zinc 
 The liquid freed from arsenic and copper by sulphuretted hydrogen may likewise be 
 precipitated by sulphide of potassium or barium, and the washed precipitate treated 
 with cold dilute l^drochloric acid, which dissolves the sulphides of manganese, zinc, 
 and iron, and leaves all the sulphide of cobalt undissolved. (Wackenroder, N. Br. 
 Arch. xvi. 133.) 
 
 The greatest difficulty in the preparation of pure cobalt-compounds is the separation 
 of the nickel. Laugier's method (vid. sup.), affords the means of obtaining a cobalt so- 
 lution free from nickel ; but it leaves a certain portion of the cobalt in the nickel pre- 
 cipitate. For more complete modes of separation, adapted to quantitative analysis, see 
 COBALT, DETECTION AND ESTIMATION OF (p. 1046). 
 
 Metallic Cobalt. Cobalt is reduced from its oxides by ignition with charcoal 
 more easily than iron, or the difficultly fusible brittle metals ; when thus reduced, 
 however, it contains carbon. The purest metal is obtained by igniting the oxalate in 
 a covered crucible, the salt, Co 2 C 2 4 , being then resolved into 2 at. cobalt and 2 at. 
 carbonic anhydride. If the oxalate or the mixture of oxide and charcoal be covered 
 with pounded glass free from reducible metals, and heated in a blast-furnace, the co- 
 balt is obtained in the form of a fused regulus. Cobalt may also be reduced from its 
 oxides by hydrogen ; and if the heat applied be not very great, the reduced metal is 
 pyrophoric, like iron reduced under similar circumstances, and takes fire on coming 
 in contact with the air, producing cobaltoso-cobaltic oxide. 
 
 Cobalt rendered compact by fusion is rather hard, has a granular fracture, and is 
 somewhat malleable at a red heat. The presence of arsenic, manganese, &c., renders 
 it brittle. It has a steel-grey colour, inclining to red ; in the polished state, however, 
 rather to white. The statements respecting its specific gravity vary from 8'513, 
 (Berzelius), to 8 7 (Lampadius). That of the metal reduced by hydrogen was found 
 by Kammelsberg, in five experiments, to vary from 8'132 to 9'495 ; mean 8*957. 
 Specific heat = 0-10696 (Eegnault), 0-1172 (De la Rive and Marcet). It fuses 
 more easily than iron, less easily than gold. It is attracted by the magnet, and is 
 capable of receiving a slight magnetic power when rubbed with a magnet, this power, 
 according to Pouillet, not being destroyed by the strongest red heat. A minute 
 quantity of arsenic destroys the magnetic power. 
 
 Cobalt is not altered by the action of air and water at ordinary temperatures, but 
 when very strongly heated, it takes fire, and is converted into cobaltoso-cobaltic oxide, 
 C 12 7 . It decomposes aqueous vapour at a red heat. It is dissolved by hydracids and 
 by dilute oxygen acids, with evolution of hydrogen, slowly however, and only when 
 heated. The solutions have a fine red colour, and contain salts corresponding in com- 
 position to the protoxide. It is easily dissolved by nitric acid, likewise forming a 
 proto-salt. 
 
 Cobalt forms several classes of compounds, the most numerous, and generally speak- 
 ing the best defined being the proto-compounds or cobaltous compounds, c. g. CoCl, 
 Co'O, Co 2 S, Co 2 S0 4 , &c. ; there are likewise cobaltic- or sesqui-compounds, e. g. Co 4 3 , 
 Co 4 S 3 ; three oxides intermediate between the two preceding; a dioxide, Co 2 2 , a disul- 
 phide, Co 2 S 2 , a tricobaltic phosphide, Co 3 P, and several classes of salts containing bases 
 in which cobalt is united with the elements of ammonia. 
 
 COBALT, AXiXiOYS OP. Cobalt unites readily by fusion with antimony and 
 arsenic, the combination being attended with incandescence; the resulting alloys are 
 brittle, and have an iron-grey colour. 
 
 Protoarsenide of Cobalt, CoAs, is found native as smaltine or tin-white 
 cobalt, being in fact the most abundant of cobalt ores. It occurs in crystals belong- 
 ing to the regular system, viz. cubes, octahedrons, dodecahedrons, and intermediate 
 forms. Cleavage octahedral, distinct ; cubic, in traces. It occurs also massive and in 
 reticulated and other imitative shapes. Specific gravity 6-3 to 6-6. Hardness 5*5. 
 Lustre metallic. Colour tin- white, inclining sometimes to steel-grey, sometimes to 
 silver- white. It tarnishes by exposure. Streak greyish-black. Brittle. Emits a 
 smell of arsenic when broken. It yields no sublimate when heated in a test-tube ; 
 but in a tube open at both ends a sublimate of arsenious acid is formed. It dissolves 
 in nitric acid, leaving a residue of arsenious acid. 
 
 Arsenide of cobalt is never found quite pure, the cobalt being always more or less 
 replaced by nickel or iron ; those varieties which contain more nickel than cobalt are 
 called Cloanthite (see NICKEL). The following are analyses of smaltine containing 
 little or no nickel; a, from Riechelsdorf in Hesse, by Stromeyer (G-ott. gelehrte 
 Anzeige, 1817, p. 72); b, from Tunaberg in Sweden, by Varrentrapp (Pogg. Ann. 
 xlviii. 505) ; c, from Schneeberg in Saxony, by E. Hofmann (ibid. xxv. 485); d, 
 from the same locality, by v. Kobell; e. from Eiechelsdorff, by Jack el (Rammelsberg' & 
 Mineralchemie, p. 23) : 
 
 VOL. I. 3 X 
 
1042 COBALT: BROMIDE CHLORIDES. 
 
 As Co Fe Cu Ni Bi S 
 
 a . 74-21 20-31 3'42 016 0-88 = 98*98 
 
 b . 69-46 23-44 4-95 0'90 = 9875 
 
 c . 70-37 13-95 11-71 1'39 179 O'Ol 0'66 = 99-88 
 
 d . 71-08 9-44 18-48 trace I'OO trace = 99-92 
 
 e . 66-02 21-21 11-60 1-90 0'04 0'49 = 101-26 
 
 The formula CoAs requires 71 '8 As and 28'2 Co. When the proportion of iron is 
 considerable, as in c, d, e, the mineral is also called Safflorite. The composition of e 
 agrees more nearly with the formula (Co ; Fe) 4 As s . Chathamite, from Chatham in 
 Connecticut, is chiefly an arsenide of nickel and iron containing 1-3 per cent, cobalt. 
 
 Smaltine occurs altered to cobalt-bloom by oxidation. 
 
 Sesquiarsenide of Cobalt. Co 2 As 3 . This compound also occurs native as 
 Skutterudite or Modumite (Tesszralkies, Hartkobaltkies, Hartkobalt), at Skut- 
 terud, near Modum in Norway. It crystallises in the regular system, exhibiting faces 
 of the cube, octahedron, dodecahedron, and trapezohedron. Cleavage cubic, distinct ; 
 dodecahedral in traces. Also massive, granular. Specific gravity 674 6-84. Hard- 
 ness = 6. Lustre bright metallic. Colour between tin-white and pale grey, some- 
 times iridescent. A crystallised specimen analysed by Wohler (Pogg. Ann. xliii. 
 591), gave 79 2 As, 18'5 Co, 1'3 Fe = 99*0, the formula requiring 78'2 per cent, As 
 and 20'8 Co. This mineral heated in a closed tube yields a sublimate of metallic 
 arsenic. 
 
 When smaltine is ignited in a retort, part of the arsenic is expelled, and there re- 
 mains a lower arsenide of cobalt, which is non-magnetic, and fuses before the blow- 
 pipe to a brittle metallic globule. In cobalt-blue works, crystallised alloys of cobalt 
 and arsenic are often formed, containing also copper and iron. (Scheerer and 
 Francis, Pogg. Ann. 1. 513.) 
 
 With yg of its weight of gold, cobalt forms, according to Hatchett, a dark yellow 
 very brittle compound ; even ^ pt. of cobalt is sufficient to render gold brittle. 
 
 The alloy of cobalt with iron is very hard and difficult to pulverise. 
 
 With mercury, cobalt forms a silver- white amalgam, which is attracted by the 
 magnet 
 
 With platinum, it forms a fusible compound. 
 
 When cobalt is fused with silver, two layers are formed, the lower consisting of 
 cobaltiferous silver, the upper of argentiferous cobalt; a small quantity of cobalt 
 renders silver brittle. 
 
 With tin, cobalt forms a somewhat ductile alloy of light violet colour. 
 
 With zinc, it unites only with great difficulty, also with lead and bismuth, which 
 exhibit with cobalt the same deportment as silver. 
 
 COBALT, BROMIDE OP. CoBr. Cobalt takes up bromine-vapour at a dull 
 red heat, forming a green compound which melts, and at a higher temperature suffers 
 partial decomposition. The compound deliquesces rapidly in the air, forming a red 
 liquid. The same solution is obtained by heating finely divided cobalt with bromine 
 and water. It turns violet-red on evaporation, and leaves a green mass when evapo- 
 rated to dryness. By evaporating the solution over oil of vitriol, red crystals of the 
 hydrated bromide acid are obtained, which soon effloresce in the dry air of the receiver, 
 but deliquesce when exposed to the air in its ordinary state. (Eammelsberg.) 
 
 A solution of the bromide forms, with excess of ammonia, a blue precipitate, which 
 turns green on exposure to the a<r, and a red solution which turns brown in the air, 
 and then sometimes deposits red quadratic tables, perhaps consisting of a compound 
 of Co^r 8 with bromide of ammonium. (Kammelsberg.) 
 
 Bromide of cobalt absorbs ammonia-gas, forming ammonio-bromide of cobalt, 
 3NH 3 .CoBr, a red powder which gradually turns brown, and is resolved by water into a 
 brown solution, and an insoluble green residue containing bromine. (Eammelsberg.) 
 
 COBAIiT, CHLORIDES OP. The protochloride, CoCl, is formed, with vivid 
 incandescence, when pulverulent cobalt is heated in a stream of chlorine-gas ; it then 
 sublimes in blue crystalline scales. It is also produced in the wet way by dissolving 
 cobalt or the protoxide in hydrochloric acid, hydrogen being evolved in the former 
 case, or by heating the sesquioxide or cobaltoso-cobaltic oxide (Co s 2 ), with hydro- 
 chloric acid, its formation being then attended with evolution of chlorine. The solu- 
 tion is pink, and yields by evaporation non-deliquescent crystals of the same colour, 
 consisting of hydrated chloride of cobalt. But if the pink solution be mixed with 
 strong hydrochloric or sulphuric acid, it turns blue the more readily as it is more con- 
 centrated and more strongly heated. The effect appears to be due to the abstraction 
 of the crystallisation-water by the strong acid. According to Proust, such a solution 
 sometimes deposits the blue crystals of the anhydrous chloride. The red colour is re- 
 stored by dilution with water. By evaporating the solution to dryness, or by heating 
 
COBALT: DETECTION AND ESTIMATION. 1043 
 
 the hydrated crystals, hydrochloric acid is evolved, and a greenish blue mass is obtained, 
 consisting of an oxychloride (Berzelius), which is decomposed at a higher tempera- 
 ture, yielding a sublimate of anhydrous chloride, and leaving an oxidised compound. 
 
 The sublimed chloride forms soft loose crystalline spangles, unctuous to the touch, 
 and of light blue colour. On exposure to the air, it takes up water and becomes rose- 
 red, and is then easily dissolved by water, forming a red solution ; but if not previously 
 hydrated in this manner, it is very slowly dissolved by water. 
 
 The red solution forms a sympathetic ink. Characters written with it on paper are 
 colourless and invisible or nearly so ; but when the paper is warmed by holding it near a 
 fire, the writing becomes visible and appears of a beautiful blue. After a while, as the 
 salt absorbs moisture, the colour disappears, but may be reproduced by the action of 
 heat. If the paper be exposed to too high a temperature, the writing becomes black, 
 and does not afterwards disappear. The addition of a nickel-salt to the solution gives 
 a green instead of a blue colour. 
 
 Ammonia-chloride of Cobalt, 2NH s .CoCl, obtained by passing ammonia-gas over 
 the heated chloride, is a bulky powder of a pale reddish- while colour. With water it 
 forms a red-brown solution, and leaves a green powder. (H. Rose.) 
 
 Sesquichloride of Cobalt, Co 2 CP, is a very unstable compound, formed by dis- 
 solving hydrated ccbaltic oxide in cold hydrochloric acid. A brown solution is thus 
 obtained, which begins to evolve chlorine, and pass into the protochloride, this 
 effect taking place instantly on heating the liquid. The Sesquichloride is also formed 
 in small quantity when chlorine is passed through a solution of the protochloride 
 mixed with hydrochloric acid, the liquid then assuming a darker colour. 
 
 COBALT, I>ETECTIOW ASffD ESTIMATION OF. 1. Blowpipe Re- 
 actions. All compounds of cobalt fused with borax or phosphorus-salt before the 
 blowpipe, either in the inner or the outer flame, impart a splendid blue colour to the 
 bead, affording an extremely delicate test of the presence of the metal. The produc- 
 tion of the blue colour in both flames distinguishes cobalt from all other metals. If 
 the substance under examination contains a large quantity of manganese or iron, as 
 well as cobalt, the bead formed in the outer flame is violet in the former case, green 
 in the latter. If the glass be then heated in the reducing flame, the manganese colour 
 disappears, and that of iron changes to bottle green, the glass then exhibiting either 
 the pure blue due to cobalt, or the greenish blue of a mixture of cobalt and iron. 
 
 Cobalt-salts mixed with carbonate of sodium, are reduced on charcoal to a grey 
 magnetic powder of metallic cobalt. 
 
 2. Reactions in Solution. Solutions of proto-salts of cobalt or co- 
 baltous salts have a rose-red colour, excepting when they are very concentrated and 
 contain a free acid, in which case they are blue ; dilution with water changes the blue 
 colour to red (p. 1042). The neutral solutions faintly redden litmus. Sulphydric acid 
 produces no precipitate in cobalt solutions containing an excess of either of the stronger 
 acids ; but in a solution of the acetate, or of any cobalt-salt mixed with acetate of 
 potassium it forms a black precipitate of sulphide of cobalt. Alkaline sulphides throw 
 down the same precipitate, insoluble in excess of the reagent. 
 
 Potash or soda forms in cobaltous solutions a blue precipitate of a basic salt, which 
 is insoluble in excess of the reagent, assumes a green or dirty bluish-grey colour on 
 exposure to the air, from formation of sesquioxide, but if protected from the air, is con- 
 verted into the hydrated protoxide of a dingy red colour. This last change takes place 
 quickly on heating the liquid, even if the air be not excluded. A solution of proto- 
 chloride of cobalt containing a little Sesquichloride, yields with potash a precipitate 
 which does not change to dingy red, even on boiling, but merely acquires a darker 
 colour. 
 
 Ammonia added in small quantity to a cobaltous solution forms a blue precipitate 
 consisting of a basic salt, which, by continued digestion with ammonia out of contact 
 of air, is converted into rose-red hydrated cobaltous oxide, the change being, however, 
 much slower than when a fixed alkali is used as the precipitant. In contact with the 
 air, the precipitate becomes green. If more ammonia be added, it dissolves and forms 
 a brownish-red liquid, which, if exposed to the air, absorbs oxygen, becomes red-brown, 
 and then contains salts of various bases, consisting of the elements of ammonia 
 united with the higher oxides of cobalt (see COBALT-BASES, AMMONIACAL). If the 
 solution contains but a small quantity of ammoniacal salts, which will be the case if 
 the original cobalt solution was neutral, potash produces in it a precipitate of hy- 
 drated sesquioxide of cobalt ; but if chloride of ammonium be added, or if the original 
 solution contained an excess of acid which has been neutralised by the ammonia, 
 potash produces no precipitate. 
 
 Neutral carbonate of potassium or sodium, forms a rose-coloured precipitate of hydro- 
 carbonate of cobalt, which, when boiled, gives off carbonic acid, and assumes a violet, 
 
 3x2 
 
1044 COBALT: DETECTION AND ESTIMATION. 
 
 or, if the alkaline carbonate is in excess, a blue colour. If the precipitate be boiled 
 for some time in contact with the air, its colour changes to green. A solution of acid 
 carbonate of potassium forms, in neutral cobaltous solutions, a rose-coloured precipi- 
 tate, with evolution of carbonic acid, the liquid retaining a reddish colour which it 
 does not lose for a very long time. The precipitate ultimately changes to a mass of 
 small rose-coloured crystals, consisting of a compound of neutral carbonate of cobalt 
 with acid carbonate of potassium. Frequently, also, there is formed a compact preci- 
 pitate, destitute of crystalline structure, and consisting of a compound of neutral car- 
 bonate of cobalt with a very small quantity of cobaltous hydrate. Carbonate of 
 ammonium produces a red precipitate of carbonate of cobalt, soluble in excess of the 
 precipitant and in chloride of ammonium ; the solution does not turn brown in contact 
 with the air. 
 
 Carbonate of barium does not in general precipitate cobaltous salts at ordinary 
 temperatures ; from a solution of the sulphate, however, the greater part of the cobalt 
 is precipitated after a very long time, so that the remaining liquid is nearly colourless. 
 From a solution of the chloride, no precipitation takes place in the cold, but by pro- 
 longed boiling, the whole of the cobalt is precipitated. 
 
 Oxalic acid produces, after some time, a faintly reddish white precipitate, which 
 gradually increases, the whole of the cobalt being ultimately thrown down as oxalate. 
 The precipitate is soluble in ammonia, less easily in carbonate of ammonium. The rose- 
 coloured ammoniacal solution, when exposed to the air, very slowly deposits the oxalate. 
 
 Phosphate of sodium produces in neutral cobaltoiis solutions, a blue precipitate, of 
 cobaltous phosphate, soluble with red colour in excess of the cobalt-solution, deposited 
 again on boiling, and redissolving as the liquid cools. 
 
 Cyanide of potassium produces a red-brown precipitate completely soluble in excess. 
 The solution has a grass-green colour, changing, after a while, to pale brown, and 
 yields, with hydrochloric acid, a reddish-white precipitate, soluble in potash. Sulphide 
 of ammonium does not precipitate the cobalt from this solution, even after a long time. 
 
 Ferrocyanide of potassium produces a green precipitate of ferrocyanide of cobalt, 
 changing after a while to grey; insoluble in hydrochloric acid. Ferricyanide of potas- 
 sium produces a reddish-brown precipitate, likewise insoluble in hydrochloric acid. 
 
 Brown peroxide of had mixed with the solution of a cobaltous salt, precipitates 
 nearly all the cobalt, after some time, in the form of sesquioxide ; the reaction is 
 accelerated by heat. 
 
 The non-precipitation by sulphydric acid in presence of free mineral acids, and the 
 reactions with alkalis, especially the formation of a brownish-red solution with excess 
 of ammonia, from which sulphide of ammonium throws down a black precipitate, are 
 together sufficient to distinguish cobaltous solutions from all others. The blowpipe 
 reaction will of course be resorted to as a confirmatory test. 
 
 Many non-volatile organic substances, such as tartaric acid, prevent the precipitation 
 of cobalt by alkalis, but not by sulphide of ammonium. 
 
 Sesqui-salts of cobalt, or cobaltic salts. The liquid formed by passing 
 chlorine into a solution of a cobaltous salt, or by treating it with chlorate of potassium 
 and hydrochloric acid, till it assumes a brown-red colour and smells strongly of 
 chlorine, exhibits the following reactions : 
 
 Sulphydric acid produces no precipitate, but only a milkiness arising from separation 
 of sulphur, the solution at the same time acquiring the rose-red colour characteristic 
 of cobaltous salts. Sulphide of ammonium, after saturation of the free acid by am- 
 monium, produces a black precipitate of sulphide of cobalt. Potash, a dark black- 
 brown precipitate of hydrated cobaltic oxide. Ammonia, a brownish-red solution, 
 which does not change by contact with the air. Carbonates of potassium and sodium: 
 green solution which deposits a small quantity of sesquioxide. Ferrocyanide of potas- 
 sium, a green ; and ferricyanide of potassium, a brownish-red precipitate. Oxalio 
 acid slowly produces a precipitate of cobaltous oxalate. 
 
 3. Quantitative estimation. Cobalt is generally precipitated from its solutions 
 by caustic potash. The basic salt at first thrown down is converted into hydrate 
 (p. 37) by boiling in the liquid, and then well washed with hot water to free it from 
 alkali, which adheres very obstinately to it. It is then dried and ignited in an atmo- 
 sphere of hydrogen, by which it is reduced to the metallic state. The reduction is 
 most easily performed by placing the dried precipitate in a platinum or porcelain 
 crucible, through the lid of which passes a tube connected with a hydrogen apparatus. 
 The crucible must be heated to full redness over a lamp ; if a lower degree of heat be 
 applied, the reduced cobalt will be pyrophoric, and is sure to oxidise partially during 
 weighing. The stream of hydrogen must be kept up till the crucible is quite cold. 
 
 As the precipitate thrown down by potash almost always retains a small quantity of 
 alkali, even after prolonged washing, the reduced metal must, after weighing, be well 
 
COBALT: ESTIMATION. 1045 
 
 Trashed with water, till the liquid which runs away no longer exhibits any alkaline 
 reaction. The metal is then to be dried, again ignited in hydrogen gas, and weighed. 
 The difference between the two weighings seldom exceeds 0'2 per cent. If the cobalt 
 has been precipitated from a solution of the sulphate, the precipitate may retain a 
 small quantity of sulphuric acid : in that case, the reduced metal will contain sulphur, 
 but never more than a mere trace, unless the precipitate has been boiled with the 
 liquid for a very long time. 
 
 Alkaline carbonates do not precipitate cobalt so completely as the caustic alkalis. 
 
 If the cobalt-solution contains ammoniacal salts, the precipitation is not complete 
 even when a caustic alkali is used, and the liquid well boiled. In that case it is 
 necessary to precipitate by sulphide of ammonium, wash the precipitate, dry it on the 
 filter, burn the filter to ashes, then dissolve the sulphide in nitric or nitromuriatic acid, 
 and precipitate with potash us above. 
 
 If the solution contains none but easily volatile acids, such as nitric or hydrochloric 
 acid, and no fixed base but cobalt, the precipitation may be dispensed with altogether, 
 the liquid being merely evaporated to dryness in the crucible, and the residue ignited 
 in an atmosphere of hydrogen, in the manner already described.. 
 
 Lastly, cobalt may be completely precipitated from its neutral solutions by nitrite of 
 potassium, in the form of potassio-cobaltic nitrite, or cobalt-yellow (p. 1058). The solu- 
 tion is evaporated to a small bulk, and neutralised by potash if it contains excess of 
 acid. A solution of nitrite of potassium is then added, together with sufficient acetic 
 acid to neutralise any free potash in the nitrite : the whole is left at rest for two 
 days, and the yellow compound which has separated is collected on a filter. The 
 filtered liquid should also be treated with nitrite of potassium and acetic acid, and 
 left at rest for some time, in order to see whether any further precipitate forms. The 
 precipitate is washed with solution of chloride or sulphate of potassium, then dissolved 
 in hydrochloric acid, the liquid being heated till it is quite free from nitrous acid, 
 and exhibits the rose-red colour of a cobaltous salt, and the cobalt is finally preci- 
 pitated by potash. This mode of precipitation serves to separate cobalt from nickel, 
 zinc, manganese, and many other metals. (A. Stromeyer, Ann. Ch. Pharm. xcvi. 218.) 
 
 4. Separation from other elements. The metals of the first group (i. 217), 
 are separated from cobalt by precipitating them with sulphydric acid, from solutions 
 acidulated with one of the stronger mineral acids. From the metals of the third group 
 and from the non-metallic elements, cobalt is separated by precipitating it as a 
 sulphide with sulphide of ammonium from neutral or alkaline solutions. In applying 
 this method to the separation of cobalt from magnesium, it is necessary to add chloride 
 of ammonium to retain the magnesia in solution, and even then the sulphide of cobalt 
 sometimes carries down with it a small quantity of magnesia. This may, however, be 
 prevented by boiling the whole till the free ammonia present is volatilised, then 
 adding a few drops of sulphide of ammonium, and filtering. 
 
 Aluminium is best separated from cobalt by precipitation as insoluble diacetate 
 (i. 13). The solution, if acid, is neutralised with carbonate of sodium, acetate of 
 sodium is added, and the liquid boiled for some time. The alumina is then precipi- 
 tated in a form in which it may be easily filtered and washed. The washing must be 
 performed with a warm weak solution of acetate of sodium, as the precipitate is slowly 
 dissolved by pure water. The whole of the cobalt remains in solution, and the 
 alumina, which may contain soda, is dissolved by hydrochloric acid, and precipitated 
 by sulphide of ammonium (i. 155). (H. Rose.) 
 
 Aluminium cannot be separated from cobalt by solution of potash, the precipitated 
 oxide of cobalt always carrying some of the alumina with it. A better method is to 
 fuse the mixture of the two bases with solid potash in a silver crucible, and extract 
 the fused mass with water. The oxide of cobalt which then remains may contain a 
 little potash, but it is free from alumina. 
 
 Another very good mode of separation is to mix the solution of the two bases with, 
 tartaric acid and excess of ammonia, which will not then precipitate either of them, 
 and add sulphide of ammonium, which will throw down the cobalt and leave the 
 aluminium in solution. The precipitated sulphide of cobalt is then to be treated 
 with nitric acid, &c., as already explained; the filtrate containing the alumina 
 evaporated to dryness, and the residue ignited to burn away the organic matter. If 
 no other base is present, the ignited residue will consist of pure alumina, which may be 
 weighed ; in the contrary case, the residue must be dissolved in hydrochloric acid, 
 and the alumina precipitated by one of the methods given on page 155, vol. i. As the 
 burning away of the organic matter takes a long time, it is perhaps better to destroy 
 it by boiling the liquid with chlorate of potassium and hydrochloric acid, and then 
 precipitate the alumina. 
 
 Cobalt may also be separated from aluminium by precipitation with nitrite oj 
 potassium. 
 
1046 COBALT: ESTIMATION. 
 
 From glucinum, cobalt may be separated by either of the two methods last-men- 
 tioned; also from yttrium, zirconium, thorium, cerium, lanthanum and 
 didymium. The last three metals may also be separated from cobalt by precipita- 
 tion with sulphate of potassium (i. 833), or with oxalic acid from a solution containing 
 excess of ammonia. 
 
 From iron, cobalt is most easily separated by precipitating the two metals with 
 sulphide of ammonium, and digesting the washed precipitate in dilute hydrochloric 
 acid, which dissolves the iron and leaves the cobalt. As, however, very small quantities 
 of sulphide of cobalt may likewise be dissolved, it is best to reprecipitate the iron by 
 sulphide of ammonium, and treat the precipitate with very dilute hydrochloric acid : any 
 slight traces of cobalt that may "be mixed with the iron will then be left undissolved. 
 
 Cobalt may also be separated from iron (in the state of sesquioxide) in the same 
 manner as aluminium, viz. by boiling the neutralised solution with acetate of sodium. 
 The iron is then precipitated, while the cobalt remains in solution. The iron preci- 
 pitate is washed with warm dilute acetate of sodium, dissolved in hydrochloric acid, 
 and the iron reprecipitated by ammonia; and the cobalt is precipitated by sulphide of 
 ammonium. If the iron in the original solution is in the state of protoxide, it must 
 first be converted into sesquioxide by heating with nitric acid. This method yields very 
 exact results. 
 
 A third method of separating iron (as sesquioxide) from cobalt, is to mix the solu- 
 tion, if neutral, with a considerable quantity of chloride of ammonium, then cautiously 
 add ammonia till a permanent precipitate of ferric oxide just begins to form, and preci- 
 pitate the rest of the iron with succinate of ammonium . The cobalt remains in solu- 
 tion, and the ferric succinate, after being washed and dried, is ignited with good access 
 of air, to prevent reduction of iron by the organic matter (see IRON). This method is 
 not, however, so good as the two preceding, as the oxide of iron, when examined by 
 the blowpipe, always exhibits the presence of a small quantity of cobalt. 
 
 Lastly, cobalt may be separated from iron by precipitation with nitrite of potassium. 
 
 From manganese (existing in solution as a manganous salt) cobalt may be easily 
 separated by precipitating the two metals as sulphides, and dissolving out the sulphide 
 of manganese with dilute hydrochloric acid, in the same way as for iron. 
 
 Another method, proposed by Liebig, is to precipitate the two metals as cyanides 
 with cyanide of potassium, then add a sufficient excess of that reagent to redissolve 
 the cyanide of cobalt and part of the cyanide of manganese. The latter is collected 
 on a filter and washed ; the filtered liquid is heated, and hydrochloric acid is slowly 
 added by drops, care being taken not to add enough to render the liquid acid ; and 
 the separation of the cobalt and manganese is effected exactly in the manner which 
 will be presently described for the separation of cobalt and nickel. The cyanide of 
 manganese previously separated by filtration is dissolved in hydrochloric acid ; the 
 solution is boiled till the hydrocyanic acid is completely volatilised, the manganese is 
 precipitated by carbonate of sodium, and the quantity thus obtained is added to that 
 determined the other way. 
 
 If the cobalt and manganese exist in solution as chlorides, the liquid may be evapo- 
 rated to dryness (being transferred to a porcelain crucible when reduced to a small 
 bulk), and the residual chlorides ignited in an atmosphere of hydrogen in the manner 
 described at p. 1043, as long as vapours of hydrochloric acid continue to escape. The 
 cobalt is then reduced to the metallic state, while the chloride of manganese remains 
 undecomposed, and may be dissolved out by water. The metallic cobalt which re- 
 mains is washed with hot water, then digested with a small quantity of very dilute 
 acetic acid, to dissolve out any small quantity of chloride of manganese that may 
 remain, afterwards ignited in a current of hydrogen, and weighed. The manganese is 
 precipitated from the solution of its chloride by carbonate of sodium. If the tempera- 
 ture be raised too high during the reduction by hydrogen, a small quantity of chloride 
 of manganese may be volatilised. 
 
 Another mode of separating cobalt from manganese, is to digest the mixed protoxides 
 
 'calcium, which converts 
 
 Another mode 01 separating cobalt trom manganese, is to aig 
 (precipitated by an alkali) in a solution of pentasulphide of i 
 them both into sulphides, dissolving the sulphide of cobalt, and leaving the sulphide 
 of manganese undissolved. 
 
 From nickel, as from most other metals of the second group, cobalt is most easily 
 separated by precipitation with nitrite of potassium, the process being performed 
 exactly as described at p. 1045. With due attention to the precautions there indi- 
 cated, the whole of the cobalt is precipitated, without a trace of nickel. 
 
 Another method is that of H. Kose, depending on the fact that protoxide of cobalt 
 in solution is converted by chlorine into sesquioxide, whereas with nickel this change 
 
 chloric 
 
 s not take place. The metals or their oxides being dissolved in excess of hydro- 
 ric acid, the solution is diluted with a large quantity of water, about a pound of 
 
COBALT: ESTIMATION. 1047 
 
 water to a gramme of the metals or their oxides. Chlorine gas is then passed through 
 the solution for several hours, till, in fact, the space above the liquid becomes per- 
 manently filled with the gas ; carbonate of barium is then added in excess ; and the whole 
 is left to stand for twelve or eighteen hours, and shaken up from time to time. The pre- 
 cipitate, consisting of sesquioxide of cobalt and carbonate of barium, is then collected 
 on a filter, and washed with cold water. The filtered liquid, which has a pure green 
 colour, contains all the nickel without a trace of cobalt. The precipitate is boiled with 
 hydrochloric acid to convert the sesquioxide of cobalt into protoxide, and dissolve it 
 together with the baryta ; the latter is then precipitated by sulphuric acid, and the 
 cobalt from the filtrate by potash. The nickel is also precipitated by potash, after the 
 removal of any baryta that the solution may contain by sulphuric acid. This method, 
 if properly executed, gives very exact results. The chief precautions to be attended 
 to, are to add a large excess of chlorine, and not to filter too soon, because the preci- 
 pitation of sesquioxide of cobalt by carbonate of barium takes a long time. 
 
 According to Henry, bromine may be used in the preceding process instead of 
 chlorine as the oxidising agent. 
 
 Liebig has given everal methods of separating these two metals, founded on the 
 difference of their reactions with cyanide of potassium. 1. The oxides of the two 
 metals are treated with hydrocyanic acid and then with potash, and the liquid warmed 
 till the whole is dissolved (pure cyanide of potassium, free from cyanate, may also be 
 used as the solvent). The reddish-yellow solution is boiled to expel free hydrocyanic 
 acid, whereupon the cobaltocyanide of potassium (KCoCy 2 ), formed in the cold, is 
 converted into cobalticyanide (K 3 Co 2 Cy 6 ), while the nickel remains in the form of 
 cyanide of nickel and potassium (KNiCy 2 ). Pure and finely-divided red oxide of 
 mercury is then added to the solution while yet warm, whereby the whole of the 
 nickel is precipitated, partly as oxide, partly as cyanide, the mercury taking its place 
 in the solution. The precipitate contains all the nickel, together with excess of mer- 
 curic oxide ; after washing and ignition, it yields pure oxide of nickel. The filtered 
 solution contains all the cobalt in the form of cobalticyanide of potassium. It is 
 supersaturated with acetic acid, boiled with sulphate of copper, which precipitates the 
 cobalt in the form of cobalticyanide of copper (2Cu 3 Co' 2 Cy 6 .7H 2 0), and the precipitate 
 retained in the liquid at a boiling-heat till it has lost its glutinous character. It is 
 then washed, dried, ignited, and dissolved in hydrochloric acid mixed with a little 
 nitric acid ; the copper is precipitated by sulphydric acid ; and the filtrate, after boiling 
 for a minute to expel the excess of that gas, is mixed with boiling caustic potash to pre- 
 cipitate the cobalt (Ann. Ch. Pharm. Ixv. 244). 2. Instead of adding the oxide of 
 mercury, the solution containing the mixed cyanides may, after cooling, be super- 
 saturated with chlorine, the precipitate of cyanide of nickel thereby produced being 
 continually redissolved by caustic potash or soda. The chlorine produces no change 
 in the cobalticyanide of potassium, but decomposes the nickel-compound, the whole of 
 the nickel being ultimately precipitated in the form of black sesquioxide. (Ann. Ch. 
 Pharm. Ixxxvii. 128.) 
 
 Liebig's first method (ibid. xli. 291), which consisted in treating the solution of 
 the mixed cyanides with excess of hydrochloric or sulphuric acid, whereby the nickel 
 was precipitated as cobalticyanide of nickel, leaving a solution of cobalticyanide of 
 potassium, has been found, both by himself and others, not to give perfectly satis- 
 factory results. The method by oxalic acid (p. 1040), and the precipitation of nickel 
 from an ammoniacal solution of the two metals by potash (see NICKEL) are not suffi- 
 ciently accurate for quantitative analysis. 
 
 F. Claudet separates cobalt from nickel and other metals in the form of the ammonio- 
 compound described on page 1052, that compound being very insoluble, while corre- 
 sponding compounds of the other metals do not appear to be formed under the same 
 circumstances. 
 
 From uranium, in the state of sesquioxide, cobalt, as protoxide, may be separated 
 by means of carbonate of barium, which throws down the uranic oxide and leaves the 
 cobalt in solution. (For other modes of separation, see URANIUM.) 
 
 From zinc, cobalt may also be easily separated by precipitation with nitrite of 
 potassium. Another mode of separation is : Convert the two metals into chlorides, 
 and reduce the chloride of cobalt with hydrogen, as described for the separation of 
 cobalt from manganese ; the chloride of zinc then remains unaltered, and may be 
 dissolved out. Thirdly, the metals may be precipitated by carbonate of sodium, the 
 carbonates dissolved in a large excess of acetic acid, and sulphydric acid gas passed 
 through the solution. The zinc is thereby precipitated as sulphide, while the cobalt 
 remains dissolved. To ensure complete separation, it is necessary to add a large 
 excess of acetic acid. Fourthly, the separation may be effected by precipitating the 
 cobalt as sesquioxide, by means of peroxide of lead (p. 1044). 
 
1048 COBALT, EARTHY COBALT : OXIDES. 
 
 6. Valuation of Cobalt-oret, The value of a cobalt-ore is estimated eithe* 
 by the amount of protoxide that it will yield, or by its power of imparting a blue 
 colour to glass and enamel. (For the latter mode of valuation we refer to the article 
 SMALT.) 
 
 To estimate the quantity of protoxide contained in a cobalt ore, the ore may be 
 treated by either of the methods already given (pp. 1039, 1040). to separate the arsenic, 
 copper, iron, &c., the cobalt being afterwards separated from the nickel, and estimated 
 by either of the processes described on pp. 1044, 1045. 
 
 (For Plattner's method of estimation in the dry way, see his Treatise on the Blowpipe, 
 translated by Muspratt, also KerFs HiUtenkiinde, iii. [1] 340, 342). 
 
 6. Atomic Weight of Cobalt. Dumas has determined the atomic weight of 
 cobalt by the quantity of silver required to decompose a known weight of the chloride. 
 Pure metallic cobalt was dissolved in nitro-muriatic acid, the solution evaporated to 
 dryness, keeping the hydrochloric acid continually in excess ; the residue ignited in a 
 stream of hydrochloric acid gas, or else heated in vacuo ; and the chloride of cobalt 
 thus obtained was decomposed by nitrate of silver. Five experiments thus made gave 
 for the atomic weight of cobalt numbers varying from 29'50 to 29*59. Dumas re- 
 gards 29'5 as the correct number (Ann. Ch. Pharm. exiii. 24). This agrees with the 
 original determination of Both of (Pogg. Ann. viii. 185), which was made by con- 
 verting a known weight of the protoxide into chloride, and then precipitating by nitrate 
 of silver. Schneid er (Pogg. Ann. ci. 317), from the analysis of the oxalate, estimated 
 the atomic weight of cobalt at 30 ; but the number 29'5 is generally regarded as correct. 
 
 COBAIiT, EARTHY, or Asbolan. A variety of wad or earthy manganese, 
 containing oxide of cobalt. (See MANGANESE, OXIDES OF, and WAD.) 
 
 COB AIiT, FXiTTORXDE OP, CoF, may be obtained by dissolving eobaltous oxide 
 or carbonate in aqueous hydrofluoric acid. The solution yields by evaporation small 
 irregular rose-coloured crystals containing CoFJPO. The compound dissolves with- 
 out decomposition in water containing free hydrofluoric acid, or in a small quantity 
 of pure water ; but with a larger quantity of water, it is resolved into an acid liquid 
 containing cobalt, and an insoluble pale red basic salt consisting of 2Co 4 F 2 O.H 2 0. or 
 2(CoO.CoF) + HO. 
 
 Fluoride of cobalt unites with the fluorides of ammonium and potassium, forming 
 sparingly soluble double salts which crystallise in pale red granular crystals. (Ber- 
 zelius.) 
 
 COBAX.T, IODIDE OP, Col, is produced by digesting finely divided metallic 
 cobalt with iodine and water, the mixture becoming heated to the boiling point. "With 
 a small quantity of water, it forms a green, and with a larger quantity, a red solution, 
 and remains, on evaporation, as a dark green deliquescent mass soluble in alcohol. 
 (Erdmann, J. pr. Chem. vii. 354.) 
 
 Ar.inionio-iodidi's of Cobalt. Iodide of cobalt absorbs 3 at. ammonia-gas, forming the 
 compound, CoL2NH 3 , which is a reddish-yellow powder. A concentrated solution of 
 iodide of cobalt forms with ammonia a reddish- white precipitate which dissolves on 
 heating, leaving only a few green flocks. The solution deposits small rose-coloured 
 crystals, which, as well as the reddish-white precipitate, consist of CoI.2NH s , but 
 appear also to contain water. When dried, they give off ammonia, turn brown and 
 afterwards green. Water decomposes them, liberating ammonia and depositing a green 
 powder. A dilute solution of iodide of cobalt forms with ammonia a blue precipitate 
 which turns green when exposed to the air, and a brown solution. (Rammelsberg, 
 Pogg. Ann. xlviii. 155.) 
 
 COBAZ.T, OXIDES OP. The following oxides of cobalt are known : 
 
 Protoxide or eobaltous oxide Co 2 or CoO 
 
 Sesquioxide or cobaltic oxide Co 4 8 or Co 2 O* 
 
 !Co 3 O 2 or Co*0* 
 Co I2 O 7 or Co 6 O 7 
 Co 16 9 or Co*0 9 
 
 The protoxide is a strong, the sesquioxide a weak base. According to Fremy, the 
 oxide Co 3 2 is also a salifiable base, which unites directly with acetic acid and exists in 
 some of the amraoniacal salts of cobalt. Fremy has also obtained salts of this nature 
 containing a dioxide of cobalt, Co 2 O ? . 
 
 Protoxide of Cobalt or Cobaltous Oxide, Co 2 0. This oxide is obtained by 
 igniting eobaltous hydrate or carbonate in close vessels ; by igniting the protochloride 
 in a stream of aqueous vapour (Schwarz enberg) ; also, mixed in various proportions 
 with sesquioxide, when finely divided cobalt burns in the air, or when the compact 
 metal is heated to redness in the air. The pure protoxide is a light greenish-grey or 
 olive-green non-magnetic powder. It is reduced to the metallic state at a red heat by 
 
COBALT: OXIDES. 1049 
 
 hydrogen, charcoal, carbonic oxide, potassium, and sodium. When heated with sul- 
 phur, it is converted into sulphide of cobalt and sulphurous anhydride ; and with 
 sulphydric acid, it yields water and sulphide of cobalt. 
 
 Hydrated cobaltous oxide, or Cobaltous hydrate, CoHO, or CoO.HO, is produced 
 when a cobaltous salt is decomposed by potash out of contact of air. A blue basic salt 
 is first produced which changes gradually at ordinary temperatures, quickly, on boiling, 
 into the rose-coloured hydrate. If the cobalt-solution be dropped into strong boiling 
 potash-ley, the change from blue to red is almost too rapid to be traced. Cobaltous 
 hydrate is a powder of a dingy rose-red colour, which gives off water at 100 C., and 
 is converted into the protoxide if the air be excluded, into a higher oxide if exposed 
 to the air. It dissolves readily in acids, forming the cobaltous salts. 
 
 Sesquioxide of Cobalt, Cobaltic Oxide, Co 4 3 , is formed when chlorine is 
 transmitted through water in which the hydrated protoxide is suspended, or when a 
 salt of the protoxide is precipitated by a solution of chloride of lime. In the former 
 case, water is decomposed by the chlorine, and hydrochloric acid produced, while the 
 oxygen of the water peroxidises the cobalt : 
 
 2Co 2 + H 2 + CP = Co0 3 + 2HCL 
 
 The sesquioxide of cobalt is precipitated as a black hydrate, which, when cautiously 
 heated to 600 or 700 C., yields the black anhydrous oxide. When sesquioxide of 
 cobalt is digested in hydrochloric acid, chlorine is evolved, and the protochloride formed. 
 Exposed to a low red heat, the sesquioxide loses oxygen, and the compound oxide. 
 Co 2 O.Co 4 3 , is produced (Hess). When protoxide of cobalt is calcined with a borax 
 glass, at a moderate heat, it absorbs oxygen, and a black mass is obtained, which, 
 mixed with manganic oxide, serves as a black colour in enamel painting. 
 
 Sesquioxide of cobalt acts as a weak base. Phosphoric, sulphuric, nitric, and hydro- 
 chloric acids dissolve its hydrate in the cold, without decomposition at first, but the 
 resulting salts are afterwards reduced to salts of the protoxide. A protosalt of 
 cobalt containing a small quantity of a sesquisalt is somewhat deepened in colour. The 
 most permanent of the sesquisalts is the ac etate ; the hydrated sesquioxide while yet 
 moist dissolves in acetic acid, slowly but completely. The solution, which has an in- 
 tense brown colour, forms a brown precipitate with alkalis and alkaline carbonates. 
 With fcrrocyanide of potassium, it forms a dark precipitate, which, if the precipitant 
 is in excess, gives up cyanogen to it, converting it into ferricyanide of potassium and 
 being itself converted into green ferrocyanide of cobalt. Alkaline oxalates colour the 
 solution yellow, forming an oxalate of the oxide Co 3 2 , or Co 6 4 . 
 
 Cobaltoso-cobaltic oxides. a. The oxide, Co 3 2 or Co 6 4 = (VO.Co'O 3 , is ob- 
 tained in the free state by heating the nitrate or oxalate of cobalt, or the hydrated ses- 
 quioxide, to redness in contact with the air (Hess, Eammelsberg); but according to 
 Beetz and Winkelblech, the oxide thus obtained is Co 12 7 . When the residue obtained 
 by gently igniting the oxalate in contact with the air is digested in strong boiling 
 hydrochloric acid, the oxide Co 8 2 remains in hard, brittle, greyish-black microscopic 
 octahedrons having a metallic lustre. The same crystalline compound is obtained by 
 strongly igniting dry protochloride of cobalt, alone or mixed with sal-ammoniac, in dry 
 air or oxygen gas. (Schwarzenberg.) 
 
 This oxide, according to Fremy, is also a salifiable base. The corresponding oxalate 
 has already been mentioned. The acetate is obtained by digesting in dilute acetic acid 
 the hydrated oxide obtained by continued action of oxygen on the blue precipitate thrown 
 down from ordinary cobalt-salts by potash not in excess. Fremy also states that when 
 chlorine is passed into the solution of ordinary acetate of cobalt, a brownish-yellow salt 
 is formed containing the base Co 6 Cl 2 3 , or Co 6 0* in which 1 at. is replaced by Cl 2 . 
 This chlorine-base exists also in some of the ammonio-compounds of cobalt (p. 45). 
 
 b. The oxide, Co 12 7 = 3Co 2 O.Co 4 3 , is said by Winkelblech to be formed by keep- 
 ing the hydrated protoxide at a red heat in the air for a considerable time, or by first 
 reducing it to the metallic state by heating it very gently in a stream of hydrogen, and 
 then burning it again by passing air through the tube. According to Rammelsberg, 
 however (Pogg. Ann. Ixxiii. 93), the oxide obtained by either of these processes is Co 3 0*. 
 
 c. Another oxide, Co 16 9 = 6Co 2 O.Co"0 3 , is said to be obtained by precipitating 
 cobaltic nitrate with ammonia, exposing the liquid to the air till the blue precipitate 
 turns green, then suspending the precipitate in water, and exposing it to the air for a 
 month till it turns quite yellow. But the yellow hydrate thus formed always retains 
 a trace of nitric acid, which cannot be removed even by long contact with water. 
 
 A cobaltic acid (or anhydride), Co0 5 , is obtained in combination with potash, by 
 strongly igniting the oxide, GVO 2 , or the protoxide or carbonate, with pure hydrate of 
 potassium. A crystalline salt is then formed which, when dried at 100 C., contains 
 K 2 0.3Co 6 5 + 3aq., and gives off 1 at. water at 130. (Schwarzenberg.) 
 
 Dioxide of Cobalt, CoO, or Co 2 O 2 , has not been obtained in the free state, but 
 may be supposed to exist in the oxycobaltic- salts (p. 1056). 
 
1050 COBALT : OXYSULPHIDE SULPHIDES. 
 
 COBALT, OXYSULFHIDE OP, Co 4 SO, or Co S. Co 0. Produced by igniting 
 the sulphate in hydrogen gas. Water and sulphurous acid escape, and there remains 
 a dark grey sintered mass which is not altered by the further action of the hydrogen. 
 Cold hydrochloric acid decomposes it, dissolving oxide of cobalt and leaving sulphide ; 
 but if heat be applied, the sulphide likewise dissolves. (Arfvedson.) 
 
 COBALT, OXYGEN-SALTS OP. The cobaltous salts are produced by dis- 
 solving metallic cobalt in the stronger acids ; by the action of acids on the protoxide, 
 hydrate, or carbonate ; by boiling the hydrate or carbonate in solutions of ammonia- 
 salts, ammonia being then evolved and a cobaltous solution formed ; and by precipita- 
 tion. The carbonate, phosphate, borate, silicate, and those which contain metallic acids, 
 are insoluble in water ; most of the others are soluble. The insoluble salts have a 
 violet or peach-blossom colour ; the dissolved salts a rose colour. The neutral solu- 
 tions redden litmus slightly. For their reactions and those of the cobaltic salts, see 
 pp. 1043, 1044. 
 
 COBALT, PHOSPHIDES OP. The tricobaltic phosphide, or tricobalt-phos- 
 phine, Co 3 P, was obtained by H. Eose as a grey powder, on passing hydrogen gas over 
 basic phosphate of cobalt ignited in a porcelain tube. It is also produced by the 
 action of phosphoretted hydrogen on chloride of cobalt. 
 
 Another phosphide containing a very large excess of cobalt is produced when pieces 
 of phosphorus are thrown on red-hot cobalt ; when 1 pt. of the metal is ignited with 
 7 pts. glacial phosphoric acid and ^ charcoal powder; and when a mixture of 
 70 pts. metallic cobalt or oxide of cobalt, 100 bone-ash, 50 pounded quartz, and 10 
 charcoal is exposed for an hour to the heat of a blast-furnace. The compound pre- 
 pared by the first or second method is bluish-white, with metallic lustre, brittle, of 
 acicular structure, more fusible than cobalt, contains 6 per cent, phosphorus, and burns 
 to a dark blue glass when heated (Pe lie tier). The product obtained by the third 
 process is of a shining white colour, very fusible, non-magnetic, and often has needle- 
 shaped crystals in its cavities. 
 
 COBALT, RED. Syn. with COBALT-BLOOM (p. 1057). 
 
 COBALT, SELEHKTIDE OP. Heated cobalt unites with selenium, forming a 
 grey mass, which exhibits metallic lustre and crystalline structure, and melts at a red 
 heat ; the combination is attended with ignition. (Berzelius.) 
 
 COBALT, SULPHIDES OP. The protosulphide, Co 2 S, or CoS, occurs 
 native as Syepoorite, a massive mineral of steel-grey colour inclining to yeliow, 
 found disseminated in grains or veins in ancient schists, associated with magnetic 
 pyrites, at Syepoor, near Rajpootanah, in North-west India. It is employed by the 
 Indian jewellers to give a rose-colour to gold. According to Middleton's analysis 
 Phil. Mag. [3] xxxviii. 352), it contains 35'36 S, and 64 '64 Co, agreeing closely with 
 the formula Co 2 S. 
 
 The protosulphide may be prepared by throwing sulphur on red-hot cobalt contained 
 in a retort, also by heating the protoxide with sulphur, and by igniting cobaltous sul- 
 phate to whiteness in a crucible lined with charcoal. As thus obtained, it is a grey 
 laminar mass having the metallic lustre ; according to Berthier, it is magnetic. In 
 the wet way, it is produced by precipitating cobaltous acetate with sulphydric acid or 
 any neutral cobaltous solution with an alkaline sulphide. The precipitate is a black 
 powder which gives off water when heated, and in the moist state slowly oxidises in the 
 air, being converted into sulphate. It is insoluble in alkalis and alkaline sulphides, 
 soluble in concentrated mineral acids, insoluble or nearly so in dilute acids. It 
 unites with acid sulphides, forming sulphur-salts, which are all insoluble in water. 
 According to Anthon, it decomposes the solutions of other metals, c. g. iron, nickel, 
 copper, and silver, a sulphide of the other metal being precipitated and the cobalt 
 taking its place in the solution. This appears somewhat inconsistent with the action 
 of dilute hydrochloric acid on a mixture of the sulphides of iron and cobalt, which, 
 according to H.Rose (p. 1044), affords a method of completely separating cobalt from 
 iron. It unites with peroxide of cobalt, forming an oxy sulphide (vid. sup.). 
 
 Sesquisulphide of Cobalt, or Cobaltous Sulphide, is obtained by precipitating 
 cobaltic acetate with sulphydric acid, or by heating cobaltic hydrate, but not to redness, 
 in an atmosphere of the same gas. It has a dark grey colour. According to Fell en- 
 berg (Pogg. Ann. 1. 73), it is obtained in graphitic laminae by igniting the protoxide with 
 sulphur and an alkali. Linnceitc or cobalt-pyrites is commonly stated to be a sesqui- 
 sulphide, but its composition approaches more nearly to that of the following compound : 
 
 Cobaltoso-cobaltic Sulphide, Co 3 S 2 , or Co'S.Co'S 3 , or <7o 3 4 = CoS.CfS 3 . 
 Linnceite from Miisen, near Siegren, in Prussia, has nearly this composition, yielding, 
 according to Wernekink's analysis, 43-25 S, 53'35 Co, 0-97 Cu, and 2'30 Fe = 98-87, 
 the formula requiring 42 S and 58 Co (Dana, ii. 66). In most varieties of this mineral, 
 however, the cobalt is replaced to a greater extent by copper or nickel. (See LINNJBITE.) 
 
COBALT-BASES, AMMONIACAL. 1051 
 
 Oxysulphide of cobalt heated in sulphydric acid gas yields a product which appears 
 to be a sulphide intermediate in composition between the proto- and sesqui-sulphides. 
 (Anthon.) 
 
 Disulphide of Cobalt, CoS, or CoS*, may be supposed to exist in combination 
 with arsenide of cobalt in cobaltine (q. v.) 
 
 COBALT-BASES, AMMOWIACAZ,. (R Claudet [1857], Phil. Mag. [4] ii. 
 253. G-enth, Ann. Ch. Pharm. Ixxx. 275. Fremy, Ann. Ch. Phys. [3] xxxv. 257. 
 Bogojski, ibid. xli. 445. Gregory, Ann. Ch. Pharm. Ixxxvii. 125. Cribbs and 
 Genth, Smithsonian Contributions, 1856 ; Sill. Am. J. [2] xxxiii. 234, 319 ; xxxiv. 96 ; 
 Ann. Ch. Pharm. civ. 150, 295; Jahresber, d. Chem. 1857, 227. Kiinzel, J. pr. 
 Chem. Ixxii. 209). Cobaltous salts treated with ammonia in a vessel protected from 
 the air unite with the ammonia, forming compounds which may be called ammonio- 
 cobalto us-salts. Most of them contain 3 at. ammonia to 1 at. of the cobalt-salt; 
 thus the chloride contains CoC1.3NH 3 + aq. ; the nitrate CoN0 3 .3NH 8 + aq. They 
 are generally crystallisable and of a rose-colour, soluble without decomposition in am- 
 monia, but decomposed by water, with formation of a basic salt (Fremy). H. Kose, 
 by treating dry chloride of cobalt with ammonia-gas, obtained the compound CoC1.2NH 3 , 
 and in like manner an ammonio- sulphate has been formed containing Co 2 S0 4 .6NH 3 . 
 
 When an ammoniacal solution of cobalt is exposed to the air, oxygen is absorbed, 
 the liquid turns brown (p. 37), and new salts are formed containing a higher oxide of 
 cobalt (either Co 4 3 or Co' J 2 ), and therefore designated generally as peroxidised 
 ammonio-cobaltsalts. Several of them containing different bases are often formed 
 at the same time. 
 
 Most of the peroxidised ammonio-cobalt salts are composed of sesquisalts of cobalt 
 (cobaltic salts), united with 2 or more molecules of ammonia. The composition of the 
 neutral salts may be illustrated by the chlorides, as in the following table : 
 
 Diammonio-cobaltic chloride Co 2 Cl s . 2NH S 
 
 Triammonio-cobaltic chloride . . . . . Co 2 Cl 3 . 3NH S 
 
 Tetrammonio-cobaltic chloride Co 2 Cl 3 . 4NH 3 
 
 Pentammonio-cobaltic chloride ..... Co 2 Cl 3 . 5NH 8 
 
 Hexammonio-cobaltic chloride Co 2 Cl 3 . 6NH 3 
 
 The formulae of the corresponding neutral nitrates are deduced from the preceding 
 by substituting NO 3 for Cl ; for the sulphates, oxalates, and other dibasic salts, the 
 number of atoms of cobalt and ammonia must of course be doubled. Thus, pentammonio- 
 cobaltic sulphate = Co'(S0 4 ) 3 .10NH 3 . There are also several acid and basic salts of 
 the same ammonio-molecules, the formulae of which will be given further on. Further, 
 there is a class of salts containing the elements of nitric oxide in addition to am- 
 monia, e.g. pentammonio-nitroso-cobaltic oxychloride = Co 4 Cl 4 0.10NH 3 .2NO. Lastly, 
 Fremy has obtained ammoniacal compounds (oxycobaltic salts) containing salts of 
 cobalt corresponding to the dioxide Co 2 2 . 
 
 DIAMMONIO-COBALTIC SALTS. The sulphite of this group is obtained by 
 adding acid sulphite of ammonium to an aqueous solution of pentammonio-cobaltic 
 chloride containing a very small quantity of ammonia, till the odour of sulphurous 
 acid becomes distinctly perceptible ; on leaving the solution to stand for some time, the 
 sulphite separates in brown, nearly insoluble octahedrons, containing Co 4 (SO s ) s .4lSiH. 3 
 + 5aq. (Kiinzel.) 
 
 TRIAMMONIO-COBALTIC SALTS. When a solution of pentammonio-cobaltic 
 chloride containing a little ammonia, is mixed with so much acid sulphite of ammonium 
 that the liquid does not smell either of ammonia or of sulphurous acid, it changes colour 
 from red to deep yellow, and deposits triammonio-cobaltic sulphite, Co 4 (S0 3 ) 3 .6NH 3 
 + aq., as a yellow powder or in crystalline needles, according to the temperature and 
 concentration of the liquid. It is insoluble in cold water, and is slowly decomposed 
 by boiling with water. Its formation is expressed by the equation : 
 2(Co 2 Cl s .5NH 3 ) H 2NH 3 + H 2 + 6(NH 4 .H.S0 3 ) = 
 [Co 4 (S0 3 ) 3 .6NH 3 + H 2 0] + 6NH 4 C1 + 3[(NH 4 ) 2 .S0 3 ]. (Ziinzel.) 
 
 TETRAMMONIO-COBALTIC SALTS. Fr&ny's Fusco-cobaltic salts. These salts 
 are formed when an ammoniacal solution of a cobaltous salt is exposed to the air, and 
 by the action of water on oxy-cobaltic salts. They are brown, and mostly uncrystal- 
 lisable, but may be obtained in the solid state by precipitation with alcohol or excess of 
 ammonia. They are slowly decomposed by boiling with water, but quickly on addition 
 of an alkali, with evolution of ammonia and precipitation of cobaltic hydrate. They are 
 
 basic salts, the nitrate containing Co 4 8 .2N 2 5 .8NIP + H 2 0, or /Q^y^g;! 3 .4NH 3 , 
 and the hyposulphate Co 4 3 .2S 2 5 .8NH 3 . 
 
1052 COBALT-BASES, AMMONIACAL. 
 
 PENTAMMONIO-COBALTIC SALTS. (Fremy, loc. cit, ; G-ibbs and Genth, loc, 
 cit.) These salts may be divided into two groups, the Roseo-cobaltic salts, which 
 hare a red colour, varying from brick to rose-red, and the Purpureo-cobaltic salts, 
 which are purple, or violet-red. The salts of both groups contain 6 at. NH 3 to 2 at. 
 cobalt, but the roseo-cobaltic salts are, for the most part, neutral, while the purpureo- 
 cobaltic salts are either basic or acid ; in some cases, however, as with the chlorides, 
 the difference consists merely in the presence or absence of water, the purple salts 
 being anhydrous, and the red hydrated. 
 
 The pentammonio-cobaltic salts are produced by the direct oxidation of ammoniacal 
 solutions of cobaltous salts, as when these solutions are exposed to the air, the red 
 and purple salts being often produced together, the latter especially when the tem- 
 perature is rather high, and the solution contains a free ammoniacal salt. The pur- 
 pureo-cobaltic salts are likewise formed by the action of acids on xantho-cobaltic 
 salts (p. 1054). 
 
 Pentammonio-cobaltic salts are nearly insoluble in cold water, but soluble in warm 
 water slightly acidulated ; the purple salts are in general less soluble than the red. 
 Their taste is purely saline, not metallic. When heated in the dry state, they decom- 
 pose, giving off ammonia, and yielding an ammonium-salt and a cobaltous salt. Their 
 aqueous solutions, when not acidulated, are decomposed by boiling, giving off ammonia 
 and depositing a hydrated cobaltoso-cobaltic oxide. The solutions of roseo-cobaltic 
 salts boiled with strong acids, are converted into purpureo-cobaltic salts. 
 
 Chlorides. 1. Hydrated Pentammonio-cobaltic chloride, or Roseo-cobaltic chloride, 
 Co 2 Cl*.5NH s + aq. This salt was discovered by Claudet and by Genth, in 1851, being 
 the first ammonio-cpbaltic salt obtained; the formulse originally assigned to it, however, 
 gave a somewhat different view of its constitution. It is the most frequent product of 
 the oxidation of an ammoniacal solution of protochloride of cobalt by exposure to the 
 air, the liquid assuming first a brown, and then a red colour, and often, especially if the 
 ammonia and the chloride of cobalt are impure, depositing a small quantity of cobaltic 
 hydrate. The presence of sal-ammoniac in the solution does not facilitate its formation. 
 The reddened solution mixed with strong hydrochloric acid, and carefully guarded 
 against rise of temperature, deposits roseo-cobaltic chloride as a brick-red precipitate, 
 which, after washing with strong hydrochloric acid, then with ice-cold water, and 
 drying at the lowest possible temperature, contains Co 2 Cl 3 .5NH 3 + H 2 0. It dissolves 
 in water either cold or warm, with dark-red colour, which, however, changes after a 
 while, especially if the solution be acidulated with hydrochloric acid and heated, to 
 violet-red. The pure aqueous solution when boiled gives off ammonia and deposits hy- 
 drated cobaltoso-cobaltic oxide, Co 3 O 2 + #H 2 0. 
 
 Koseo-cobaltic chloride forms double salts with the chlorides of the more electro- 
 negative metals. 
 
 Purpureo-cobaltic chloride, Co 2 Cl s .5XH s . It has already been mentioned, that the 
 red solution of roseo-cobaltic chloride changes to violet when heated with hydrochloric 
 acid. The same change takes place slowly in the dry salt. This purple modification 
 is often formed, together with the red one and sometimes alone, during the oxidation 
 of ammonio-cobaltous chloride, especially if the temperature is rather high, and the 
 solution contains sal-ammoniac. By boiling the oxidised liquid with excess of hydro- 
 chloric acid, and crystallising the precipitated carmine-coloured powder from water 
 acidulated with the same acid, the purpureo-cobaltic chloride is obtained pure. It may 
 also be prepared by boiling a xantho-cobaltic salt (p. 1054), the nitrate being best 
 adapted for the purpose with hydrochloric acid; lastly, by boiling any other pur- 
 pureo-cobaltic salt with hydrochloric acid. It forms small violet-red or purple crystals. 
 which, according to Dana, are dimetric combinations, P . oo Poo . Poo . Length of 
 principal axis = 1'9016. P : P in the lateral edges = 114 8' ; in the terminal edges, 
 107 12'. Specific gravity 1'802. The crystals are anhydrous, nearly insoluble in cold 
 water, soluble without decomposition in boiling water slightly acidulated with hydro- 
 chloric acid. A larger addition of hydrochloric acid, or a solution of an alkaline 
 chloride, precipitates it slowly in the cold, quickly on boiling. The solution yields with 
 dichloride of platinum a brown-red precipitate, composed of flat microscopic needles 
 containing Co 2 Cl 3 .5NH 3 .2PtCP. 
 
 Cyanides. Roseo-cobaltic cobalticyanide, (Co 8 Cy 3 .5NH 3 ).Co 2 Cy 3 + f H 2 0, is precipi- 
 tated by cobalticyanide of potassium from roseo-cobaltic solutions, in cherry-coloured 
 crystals apparently having the form of rhombic prisms, insoluble in cold water, decom- 
 posed by hot water. The ferricyanide, (Co 2 Cy s .5NH 3 ).Fe 2 Cy 3 + p[*0, is an orange- 
 coloured crystalline precipitate, possessing similar properties. 
 
 Oxides. Roseo-cobaltic oxide is obtained in solution by decomposing the solution 
 of the chloride with oxide of silver, or better since chloride of silver is somewhat 
 soluble in roseo-cobaltic chloride by decomposing the sulphate with baryta-water. 
 
COBALT-BASES, AMMONIACAL. 1053 
 
 The solution has an alkaline taste and reaction, absorbs carbonic acid from the air, 
 and decomposes with facility. Purpureo-cobaltic oxide, obtained in like manner, forms 
 a violet-red alkaline solution, which absorbs carbonic acid from the air, and suffers 
 decomposition when concentrated. 
 
 Nitrates. The neutral or roseo-cobaltic nitrate, is obtained, as a shining yellow 
 precipitate, when an ammoniacal solution of cobaltous nitrate is left to oxidise in the air, 
 (crystals of Fremy's oxycobaltic nitrate are frequently also formed at first, but subse- 
 quently disappear). The deep wine-red liquid yields, by spontaneous evaporation, red 
 crystals, containing Co 2 (N0 3 ) 3 .5NH s . + H 2 0, easily soluble even in cold water. Accord- 
 ing to Dana, they are monoclinic combinations QO Poo . [oo Poo ] . + Poo . Poo . oo P. 
 Inclination of faces, ooP : ooP in the clinodiagonal principal section = 103; 
 oo Poo : Poo = 140 30' ; ooPoo : Poo = 136. From the solution of these crystals, 
 or from the original oxidised ammoniacal solution, nitric acid added in the cold 
 throws down a brick-red precipitate of the hydrated salt ; but on boiling the liquid 
 with nitric acid, the anhydrous nitrate, Co 2 (N0 3 ) 3 .5NH 3 , is thrown down as a violet- 
 red crystalline precipitate. It dissolves in dilute ammonia and separates from the 
 solution by spontaneous evaporation in dimetric crystals P . Poo . oo P . oo Poo . 3P3. 
 Inclination of P : P in the lateral edges, = 82 40'. This anhydrous salt is nearly 
 insoluble in cold water, more soluble in hot water, but the solution is easily de- 
 composed by heat ; addition of nitric acid prevents the decomposition. The anhy- 
 drous salt explodes when heated, giving off nitrous vapours, and leaving black 
 sesquioxide of cobalt. A basic nitrate, probably Co 4 3 .2N 2 5 .10NH 3 + 7H 2 or 
 
 \ Co 2 ?" H ! 3 - 5NH3 + 32 2 0, is obtained in purple scaly crystals, when a solution of the 
 hydrated neutral nitrate, mixed with a large quantity of nitrate of ammonium and a 
 little free ammonia is left to evaporate. These crystals are decomposed by solution 
 in water, and when boiled with hydrochloric acid, yield with brisk effervescence, a 
 purple-red solution and a deposit of purpureo-cobaltic chloride (Gribbs and Genth). 
 Both this basic nitrate and the anhydrous neutral nitrate appear to belong to the so- 
 called purpureo-cobaltic group. Kiinzel, by exposing an ammoniacal solution of 
 cobaltous nitrate to the air till it had acquired a dark olive-brown colour, and then 
 adding nitrate of ammonium, obtained a yellow crystalline precipitate, to which he 
 assigns the formula 2(Co 4 3 .10NH 3 ).5N 8 5 . 
 
 Oxalates. Eoseo-cobaltic oxalate is precipitated by oxalate of ammonium from 
 a solution of the chloride immediately, from the nitrate very slowly ; it may be puri- 
 fied by recrystallisation from water containing ammonia. The cherry-coloured crys- 
 tals, which are rhombic prisms of 101 48', with a brachydome of 108 54', contain 
 ( C 2 "0 2 ) 3 ) 
 CC 4 V I O 6 -!^-^- 3 + 6aq. ; they are nearly insoluble in pure water. The basic, orpur- 
 
 (C"0 2 ) 2 ) 
 pureo-cobaltic oxatatc, (Q 4\ T i [ 5 .5NH 3 + 3 aq., separates in violet-red needles on 
 
 adding oxalate of ammonium to a solution of purpureo-cobaltic chloride. 
 
 Oxalo- sulphates. Antacid oxalo-sulpkate, Co 4 3 .2C 2 O s .2S0 3 .10NH 3 + 3H 2 or 
 (C 2 2 )") 
 
 (SO 2 )" \ 4 .5NH 3 + H 2 0, is obtained in brick-red, ill-defined needles by boiling 
 (Co 2 )"'H) f 
 
 roseo-cobaltic sulphate for several hours with excess of oxalic acid. The solution 
 of this salt assumes a violet-red colour on addition of ammonia, and, if exactly 
 neutralised, yields by evaporation prismatic crystals of a basic oxalo-sulphate. 
 (C'O 2 )") 
 
 (SO 2 )" ^OUONH 3 -!- 7H 2 0, which is more soluble than the acid salt, and is easily de- 
 (Co)<* ( 
 composed by boiling. 
 
 Sulphates. Eoseo-cobaltic sulphate is generally (but not always) produced in an 
 ammoniacal solution of cobaltous sulphate by atmospheric oxidation, the liquid be- 
 coming first brown and then dark red. On carefully adding sulphuric acid to this red 
 solution, the sulphate is deposited as a brick-red crystalline powder, which may be 
 purified by washing with cold water and recrystallisation from a slightly acidulated 
 
 solution. The cherry-coloured crystals, containing > 4 2 ^|o 6 .10NH 8 + 5H 2 0, are, 
 
 according to Dana, dimetric combinations, P . 2P . Poo . OP . ooP . ooPoo . Inclination 
 of P : P in the terminal edges = 107 20'. Length of principal axis = 1-0866. The 
 salt is nearly insoluble in cold water, sparingly soluble in boiling water, and crystal- 
 lises from the solution on cooling. It dissolves in dilute ammonia, and crystallises 
 unaltered from the purple-red solution. On boiling the neutral salt, a dark brown 
 
1054 COBALT-BASES, AMMONIACAL. 
 
 powder separates, which, after drying in the air, contains Co 8 O 2 + 3H-0, while luteo- 
 cobaltic sulphate remains in solution, being, however, partially decomposed. 
 
 An acid (purpureo-cobaltic) sulphate, Co 4 O s .4S0 3 .10NH s + 5H 2 0, or / c ^23? 4 .5NH S 
 
 + 2H-0, is obtained by mixing the anhydrous chloride (p. 46) with oil of vitriol to & 
 thick pulp, diluting the solution with twice its bulk of water, as soon as the evolution 
 of hydrochloric acid has ceased, then washing the violet-red needles which separate 
 with a little cold water, and pressing them ; also by adding oil of vitriol to roseo- 
 cobaltic sulphate till an oily liquid is produced ; digesting this for an hour or two, 
 taking care to avoid escape of oxygen, diluting the evolved purple solution with an 
 equal bulk of water, and recrystallising. The crystals are red prisms; according 
 
 to Dana, rhombic hemihedral combinations, ooP . ooPoo . ifoo . - . oP2. In- 
 
 clination ofooP: ooP = 106; |Poo: |Poo, on the principal axis = 122 42'. The 
 salt has an acid taste and reaction, dissolves easily in water, but is quickly converted 
 into the neutral (roseo-cobaltic) sulphate ; especially by slow evaporation of a solution 
 prepared with the aid of heat. (Gribbs and Genth.) 
 
 Su lp hit e. S^wi | 8 .5NH S + f H 2 0. Black-brown, heavy, amorphous precipitate, 
 
 formed when sulphurous acid gas is passed through a dilute ammoniacal solution of 
 pentammonio-cobaltic chloride ; also by passing the gas through water in which tri- 
 ammonio-cobaltic sulphite (p. 1051) is suspended. It is insoluble in cold water, and is 
 
 decomposed by boiling water. (Kiinzel.) 
 
 NlTROSO-PENTAMMONIO-COBALTIC, Or XANTHO-CO BALTIC SALTS. (Gribbs 
 
 and Gfenth, loc. tit.} These salts are produced by passing the nitrous vapours evolved 
 from a mixture of nitric acid and starch or sawdust, into ammoniacal solutions of 
 cobaltous salts, or into neutral, acid, or ammoniacal solutions of roseo- or purpureo- 
 cobaltic salts. The gas is absorbed ; fumes of carbonate of ammonia make their appear- 
 ance ; the liquid gradually assumes a dark reddish-brown colour, and then, on cooling, 
 generally deposits a xantho-cobaltic salt. 
 
 Xantho-cobaltic salts are brownish-yellow, more soluble in water than the roseo- 
 or purpureo-cobaltic salts, the dilute solutions having a yellow, the more concentrated 
 solutions a dark brown colour. They decompose, though not easily, when these solu- 
 tions are boiled sometimes also below the boiling temperature giving off ammonia 
 and depositing a dark-coloured heavy powder. The addition of a few drops of acetic 
 acid prevents this decomposition ; but, on adding a small quantity of an inorganic acid, 
 nitric oxide gas is evolved, and a purpureo-cobaltic salt is formed, which, however, is 
 difficult to separate from the undecomposed xantho-cobaltic salt. 
 
 The xantho-cobaltic salts appear to have the composition of sesquisalts of cobalt, 
 associated with 5 or 10 at. NH 3 , 1 or 2 at. NO, and 1 or 2 at, water. /mznv i 
 
 The chloride, or rather oxy chloride, Co 4 OCl 4 .10NIP.2NO + H 2 0, or >CO*)'"H| 
 6NH S .NO, is not produced by either of the reactions just mentioned, but may be 
 prepared by decomposing the sulphate with chloride of barium, and evaporating the 
 filtrate at a gentle heat, after adding a few drops of acetic acid. It forms brownish- 
 yellow, iridescent crystals. Its solution, mixed with trichloride of gold, yields a double 
 salt, which, by recrystallisation from hot water, is obtained in brownish-yellow, iri- 
 descent prisms, containing Co 4 OCl 4 .10NH 3 .2N0.2AuCl 3 + 2H-0. The chlorbplati- 
 nate, Co 4 OCl 4 .10NH 3 .2NO.4PtCl 2 + 2H 8 0, is nearly insoluble in water, but maybe 
 crystallised from hot dilute hydrochloric acid. The chloromercurate, CVOC1*. 
 10NH 3 .2N0.8HgCl -t- 2lPO,is obtained by precipitation in pale brownish-yellow laminae; 
 by recrystallisation from hot slightly acidulated water, in brownish-yellow needles. 
 
 Xantho-cobaltic ferrocyanide, Co 4 OCy 4 .10NH'.2NO.2FeCy + 7H 2 0, is ob- 
 tained by precipitating the nitrate with ferrocyanide of potassium (the solutions of the 
 chloride and sulphate are merely clouded by that reagent) in orange-yellow prismatic 
 crystals, which give up their water easily and without decomposition, are insoluble in 
 cold water, and are decomposed by hot water. 
 
 The nitrate, which is a basic salt, containing Co 4 8 .2N 2 5 .10NH 3 .2NO + H 2 0, 
 
 or /p 2 y,JjV0 3 .5NH 3 .NO, forms light brownish -yellow quadratic prisms, having 
 P : P in the lateral edges, between 100 45' and 101 15'. 
 The oxalate, Co 4 3 .2C0 3 .10NH s .2NO + 5IFO = /S 8 .5NH 3 .NO -f 2H 2 0, is 
 
 obtained by precipitation in yellow acuminated crystals, insoluble in cold, sparingly 
 soluble in boiling water, decomposed by boiling. 
 
COBALT-BASES, AMMONIACAL. 1055 
 
 Thesulphat e, Co 4 3 .2S0 8 . 1 ONH 3 .2NO + H 2 or, jj 8 .5NH 3 .NO, crystal 
 
 lises in thin plates, apparently rhombic. It dissolves in strong sulphuric acid, giving 
 off but little nitric oxide, and forming a red oily liquid, which gives off nitric oxide 
 abundantly on addition of water, while the remaining liquid consists chiefly of am- 
 monio-cobaltous sulphate, usually mixed with a small quantity of acid purpureo-co- 
 baltic sulphate. 
 
 HEXAMMONIO-COBALTIC, or LUTEO-COBALTIC SALTS. (Fr6my; G-ibbs 
 and G-enth, loc. cit.} These salts, discovered by Fremy, are often produced by the 
 direct oxidation of ammonio-cobaltous solutions ; frequently also by the decomposition 
 of pentammonio-cobaltic salts, although their molecule contains an additional atom of 
 ammonia. They are of yellow or brownish-yellow colour, more soluble in water than 
 the roseo-cobaltic salts, and yield brownish-yellow solutions. They are very permanent 
 in presence of acids, but are decomposed by continued heating with sulphuric acid ; in 
 neutral or alkaline solutions they are easily decomposed by boiling. 
 
 Luteo-cobaltic chloride, Co 2 Cl 3 .6NH 3 , is often formed during the oxidation, by 
 exposure to the air, of an ammoniacal solution of protochloride of cobalt mixed with a 
 large quantity of coarsely-pounded sal-ammoniac (in other cases, the products are 
 roseo and purpureo-cobaltic chloride) ; almost always, if the ammoniacal solution con- 
 tains sulphate of cobalt as well as chloride : in the latter case, a salt is formed contain- 
 ing sulphuric and hydrochloric acids, and this, when boiled with hydrochloric acid 
 and chloride of barium, yields a solution of luteo-cobaltic chloride. This salt, purified 
 by repeated crystallisation, forms brownish orange-coloured crystals of specific gravity 
 17016. They belong to the trimetric system, and, according to Dana, exhibit the 
 faces ooP . OP . Poo . 3Poo , two faces, a>P3, on one side only of the macrodiagonal, 
 and four faces, |P, lying in one zone. Inclination of coP : ooP = 113 16'. It dis- 
 solves easily in boiling water, and separates for the most part as the solution cools. 
 It is precipitated unaltered by hydrochloric acid and the chlorides of the alkali-metals. 
 Boiling aqueous ammonia decomposes it slowly, with formation of chloride of ammonium 
 and a dark brown oxide of cobalt. 
 
 Concentrated solutions of luteo-cobaltic chloride and dichloride of platinum, yield 
 orange-coloured needles of a chloroplatinate containing Co 2 Cl 3 .3PtCl 2 .6NH 3 + 3aq. ; 
 dilute solutions deposit yellow needles of the same compound with 10| at. water ; 
 these, according to Dana, are monoclinic combinations ooP . ooPoo . OP. Inclination 
 of P : P, in the clinodiagonal section, = 107 10'; OP : ooPoo = 114 15'. The 
 crystals are often twins united by the face OP. Trichloride of gold forms with luteo- 
 cobaltic chloride a yellow precipitate, consisting of small granular crystals, Co 2 Cl s . 
 AuCP.6NH 3 . 
 
 Luteo-cobaltic iodide, Co 2 I 3 .6NH 3 , is thrown down by iodide of potassium from 
 luteo-cobaltic solutions, as a yellow precipitate, nearly insoluble in cold water, mode- 
 rately soluble in hot water, and separating in brownish-yellow crystals on evaporation. 
 The bromide is obtained in like manner as a deep yellow precipitate, in other respects 
 resembling the iodide. 
 
 Luteo-cobaltic cobalticyanide (Co 2 Cy 8 ) 2 .6NH 3 + f H 2 0, is precipitated by co- 
 balticyanide of potassium as a yellowish flesh-coloured precipitate composed of micro- 
 scopic, oblique rhombic crystals. Fcrricyanide of potassium forms an orange-yellow 
 precipitate, exhibiting the same forms under the microscope. 
 
 Luteo-cobaltic oxide. By decomposing the sulphate with baryta-water, a 
 brownish-yellow alkaline solution is formed, which absorbs carbonic acid from the 
 air, and is decomposed by evaporation, with evolution of ammonia and deposition of a 
 black powder. 
 
 Luteo-cobaltic nitrate, Co 2 (N0 8 ) s .6NH 3 , separates from an oxidised solution of 
 ammonio-cobaltous nitrate in orange-coloured crystalline laminae, the supernatant 
 liquor being usually red and containing roseo-cobaltic nitrate. The salt, purified 
 by recrystallisation, forms crystals belonging to the dimetric system, with the faces 
 P . 3P . OP. Angle of P : P in the lateral edges = 110 20'; of 3P : 3P in the same 
 = 153 52'. Length of principal axis for P = 1-0161. 
 
 Carbonates. The neutral carbonate, probably Co 1 (C0 3 ) 8 .12NH 3 + 7H 2 0, is ob- 
 tained by decomposing a solution of the chloride with carbonate of silver, and leaving 
 the liquid to evaporate, in rhombic crystals, ooP . oopco . Poo Inclination of ooP : ooP 
 = 116 50'; Poo : Poo on the principal axis = 114 16'. If the air has had access to 
 the solution, the crystals are generally mixed with those of the acid salt. The acid 
 carbonate, (Co 2 )'"HC 2 6 .6NH 3 + |aq., separates, on passing carbonic acid gas into the 
 solution of the neutral salt, in large brown-red crystals, which, according to Dana, are 
 monoclinic combinations, as P . ooPao . [ ooPoo ] . OP. P. + 2Poo . Inclination of 
 
1056 COBALT-BASES, AMMONIACAL. 
 
 ooP : ooP, in the clinodiagonal section, = 85 54'; OP : ooP = 102 20'; OP : ooPoo 
 = 71 44'; OP : -P = 139 50'; ooP : +2Po> = 111 46'. 
 
 Oxalates. The neutral oxalate is thrown down by oxalate of ammonia, as a reddish- 
 yellow precipitate composed of slender needles, insoluble in water, easily soluble in 
 oxalic acid, and separating therefrom in wine-yellow, efflorescent, prismatic crystals, 
 containing Co 4 (C 2 4 ) 3 .l2NH 8 + 4H 2 0. The acid oxalate was not obtained. 
 
 Luteo-cobaltic sulphate is obtained, mixed with the chloride, when an ammo- 
 niacal solution of cobaltous sulphate and chloride mixed with a large excess of coarsely 
 pulverised sal-ammoniac, is left exposed to the air. The crystalline mass deposited at the 
 bottom of the vessel is dissolved in hot water ; the filtrate is acidulated with a few drops 
 of sulphuric acid and treated with sulphate of silver ; and the liquid, after filtration and 
 concentration, is left to crystallise. The salt is also (though not constantly) produced by 
 the action of strong ammonia on roseo-cobaltic sulphate, the change consisting simply 
 in the assumption of 1 at. NH 8 : also as a product of the decomposition of roseo-cobaltic 
 sulphate (a salt of another base, not yet further examined, called by Genth and Gribbs 
 praveo-cobalt, being sometimes formed simultaneously). The wine-yellow crystals of 
 luteo-cobaltic sulphate contain Co 4 (S0 4 ) 3 .12NH 8 -f 5H 2 0, and give off 4 at. water in dry 
 air, or_in vacuo. According to Dana, they are trimetric combinations, ooP . OP . fP . 
 f P . 3Poo . Poo ; also with 3Poo or ooPf . Poo . 3Poo ; also with OP and Poo . In- 
 clination of ooP : ooP = 113 38' and 66 22'; ooPf : oof = 88 44' and 91 16'; 
 Poo; P. oo, on the principal axis = 112 8'; Poo : Poo, also on the same = 88 22'; 
 Luteo-cobaltic sulphate is isomorphous with the chloride, and the two salts are capable 
 of crystallising together in all proportions. 
 
 Luteo-cobaltic chromate, obtained by precipitation (pure only from the nitrate), 
 is yellow, soluble in hot water, and separates therefrom in yellow crystals. This salt 
 also crystallises in all proportions with the chloride. (Gribbs and Gf enth.) 
 
 AMMONIO-PERCOBALTIC SALTS, or OXYCOBALTIC SALTS. Fremy (loc.cit.). 
 These salts contain 5 at. ammonia associated with a basic salt of dioxide of cobalt. 
 Thus, the nitrate is Co 2 2 .N 2 5 .5NH 3 . + H 2 0, and the sulphate, Co 2 2 .S0 3 .5NH 3 + f H 2 0. 
 They are produced by the. action of the air on concentrated solutions of ammonio- 
 cobaltous salts. They have generally an olive-brown colour ; crystallise well, are but 
 slightly soluble in the ammoniacal liquid, and are decomposed by water, especially when 
 hot, with evolution of oxygen, liberation of ammonia, and separation of a green basic 
 salt containing the oxide Co 3 2 . The nitrate of this group was first prepared, though 
 not analysed, by L. G-melin. (Handbook, v. 342.) 
 
 The oxycobaltic salts may be supposed to contain the diatomic base, Co 2 0, thus : 
 
 The nitrate = 
 The sulphate = 
 
 2 .5NH 3 . 
 2 .5NH 3 . 
 
 (Co 2 0)" 
 
 General formula of the Ammoniacal Cobalt-compounds. These compounds may be 
 represented as ammonium-salts, in which part of the hydrogen in one or more molecules 
 of NH 4 is replaced by ammonium itself, and another portion, in the ammonio- cobaltous 
 salts, by the monatomic radicle Co' = 29'5 ; in the ammonio-cobaltic salts by the tri- 
 atomic radicle Ceo'" = Co 2 = 59 ; and in the ammonio-percobaltic salts, by the 
 diatomic radicle (CcoO)" = 75. Such formulae have been proposed by "Weltzien 
 (Ann. Ch. Pharm. xcvii. 19), and H. Schiff (Compt. rend. liii. 411). 
 
 In the following formulae, which are nearly the same as those of Schiff, the symbol 
 Am stands for NH 4 and X for a monatomic acid radicle, such as nitryl, NO 2 . 
 
 a. Diammonio-cobaltous salts 
 
 
 ) 
 
 ft. Triammonio-cotaltous salts .... == N(Co'Am 2 H) 
 
 7. Pentammonio-percobaltic salts (oxycobaltic salts) = N2 [( c coO)"Am 3 H 3 ] | 
 
 S. Tetrammonio-cobaltic salts (fusco-cobaltic salts) = N ^ Cco " /A ^. 8 ) | Q 8 
 
 . Pentammonio-cobaltic salts: 
 
 Diacid,orPurpureo-cobaltic . . . N(Cco'"Am 2 Ip | Q* 
 
 Triacid,orKoseo-cobaltic .... N 9 (Cco"'Am 2 IF) j Q3 
 
 C. Xantho-cobaltic salts ..... = N 3 [Cco'"Am 2 H(NO)]j 08 
 
 77. Hexammonio-cobaltic salts (luteo-cobaltic salts) =* N8 ( c co'"Am 3 H*)| O3 
 
COB ALT-BLOOM COB ALTINE. 1057 
 
 Romo of these formulae, viz. those of the ftisco-, pnrpureo-, and xantho-cobaltic salts, 
 differ by 1 at. H from those previously given ; but in compounds of such complexity, 
 the question of 1 atom of hydrogen more or less can scarcely be decided by analysis. 
 
 The formulae of the chlorides and oxychlorides are deduced from those in the table 
 by substituting 1 or more at. 01 for a corresponding number of atoms of XO. 
 
 The salts /8 are transformed, by the joint action of ammonia and oxygen >into 7, 
 and these, by further oxidation, are resolved into ammonia and the salts 5, which 
 again, by addition of 1 at NH S are transformed into e ; and these last, by the further 
 action of ammonia, yield 77. The salts C ar e formed by the action of nitrous acid on 
 , and are reconverted into the diacid salts e, with evolution of nitric oxide, by the 
 action of strong acids. 
 
 For Weltzien's formulae, see Graham's Elements of Chemistry, 2nd edition, ii. 721. 
 Gibbs and Genth object to the representation of these compounds as ammonium-salts, 
 and express their composition by means of formulae involving so-called conjugate 
 radicles, such as 6NH 3 ~Co 2 in the luteo-cobaltic salts, and NO'~~5NH s ~Co 2 in the 
 xantho-cobaltic salts. It is not easy to say what is gained by such a mode of repre- 
 sentation. 
 
 COBAI.T-BX.OOftX. En/thrine, Prismatic Red Cobalt, Red Cobalt- Ochre, Cobalt- 
 mica, Kobalt-bluthe.A. hydrated arsenate of cobalt, Co 3 As0 4 + 4H 2 0, or SCoO.AsO 5 
 + SHO, occurring in monoclinic crystals, in which the orthodiagonal, clinodiagonal, and 
 principal axis are as 1'3818 : 1 : 0-9747. Inclination of clinodiagonal to principal axis = 
 70 54' ; oo P : oo P = 111 16'. Observed faces + P oo . + P . [ ooP oo] .[ oo P |] . 
 ooPf . oo P oo sometimes with + 3P oo and + f P oo between oo P oo and + P oo. The 
 faces oo P oo and + P oo are vertically striated. It is likewise found in glo- 
 bular and vermiform masses ; also pulverulent, incrusting. Specific gravity = 2-948. 
 Hardness, T5 2*5, least on [ooPoo]. Lustre on [ooPoo] pearly; on the other 
 faces, adamantine inclining to vitreous. Colour, red of various shades, grey and green ; 
 the red tints incline to blue when viewed at right angles to cleavage. Streak, peach- 
 blossom red. Sectile. Flexible in thin plates. 
 
 Analyses of cobalt-bloom from Schneeberg by Karsten (Pogg. Ann. Ix. 251), gave 
 As 2 5 Co 2 Fe 2 Ca 2 H 2 
 
 38-43 36-52 1-01 24-10 = 100-06 
 
 38-30 33-42 4'01 24-08 = 99'81 
 
 38-10 29-19 8-00 23'90 = 99-19 
 
 The formula requires 38'43 As 2 5 , 37'53 Co 2 0, and 24-02 water. 
 
 The mineral, when heated in a tube, yields water and turns blue if pure, green if it 
 contains nickel or iron. Before the blowpipe, on charcoal, it gives an arsenical odour 
 and melts in the inner flame to a dark grey bead of arsenical cobalt ; gives with fluxes 
 the usual cobalt reaction. Dissolves easily in acids. 
 
 Earthy cobalt-bloom (Kobalt-bcschlag), of peach-blossom colour, is arsenate of 
 cobalt with free arsenious acid. A specimen from Schneeberg analysed by Karsten 
 gave 51-00 per cent. As 2 O 3 , 19-10 As'O 5 , 16-60 Co 8 0, 2-10 Fe 2 0, and 11-90 water 
 (= 100-70), with traces of nickel, lime, and sulphuric acid. 
 
 Cobalt-bloom occurs in minute crystals at Schneeberg in Saxony, Saalfeld in Thu- 
 ringia, Riechelsdorf in Hessia, Wolfach and Wittichen in Baden, and Modum in Nor- 
 way. The earthy varieties are found in Dauphiny, in Cornwall, and near Alston, 
 Cumberland. A green variety occurs at Platten in Bohemia. The mineral is also 
 found at Prince's mine, Lake Superior, in calcite. When abundant, it is used for 
 the manufacture of smalt. (Dana, ii. 407.) 
 
 COBAXiT-BXitTE. A pigment of a fine blue colour, like that of ultramarine, 
 obtained by mixing the solution of a cobalt-salt, perfectly free from iron and nickel, 
 with a solution of pure alum, precipitating with an alkaline carbonate, carefully wash- 
 ing the precipitate, then drying and igniting it strongly. It is a compound of protoxide 
 of cobalt and alumina, and is used both as oil and water colour. 
 
 COBAI&T-GIiANCE. See CoBALTINE. 
 
 COBALT-GREEN. Rinmaris Green. A permanent green pigment prepared 
 by precipitating a mixture of the sulphates of zinc and cobalt with carbonate of 
 sodium, and igniting the precipitate after thorough washing ; or by mixing a solution 
 of nitrate of cobalt with oxide or nitrate of zinc, then evaporating and igniting. 
 
 COB ALTINE. Cobalt-glance, Glance- cobalt, Silver-white cobalt. Cobalt gris. 
 A native sulpharsenide of cobalt, Co 2 AsS or Co As . CoS 2 , occurring in forms of the 
 regular system, viz. the cube, octahedron, pentagonal dodecahedron, and several com- 
 binations of these forms. Cleavage parallel to the cubic faces. Also massive, granular 
 or compact. Specific gravity = 6 6-3. Hardness = 5'5. Fracture imperfect, con- 
 
 VOL. I. 3 Y 
 
1058 COBALT-MICA COBALT-YELLOW. 
 
 choi'dal, uneven. Opaque, with metallic lustre. Colour silver- white, inclining to copper- 
 red, occasionally tarnished. Streak, greyish-black. Brittle. 
 
 Before the blowpipe, it gives off fumes of arsenic, and yields, after roasting, a dull 
 black feebly magnetic globule, which colours borax blue. It dissolves in warm nitric 
 acid leaving a residue of arsenious acid. 
 
 Analyses. a, from Skutterud by Stromeyer ; b, from Siegen by Schnabel ; c, from 
 Orowitza in the Banat by Huberdt ; d, from the same by Patera ; e, from Skutterud by 
 Ebbinghaus ; f, from Siegen by Schnabel. (Eamtnelsberg 1 s Mineralchemie, p. 60.) 
 
 Co Fe As Sb S 
 
 a . . 33-10 3-23 43-46 . . 20-08 = 99-88 
 
 b . . 2977 6-38 4475 . . 19-10 = 100-00 
 
 c . . 30-37 5-75 4413 . . 19-75 = 100-00 
 
 d . . 32-03 4-56 43-63 . . 1978 = 100-00 
 
 e . . 32-60 3-47 43'68 . . 20-58 = 100-34 
 
 / . . 8-67 25-98 42-53 2-84 19-98 = 100-00 
 
 The formula Co 2 AsS requires 35-5 Co, 45 -2 As, and 19 -3 S. In analysis /, three- 
 fourths of the cobalt is replaced by iron. 
 
 Cobaltine occurs in large splendid crystals atTunaberg, Riddarhyttan, and Hokansbo 
 in Sweden, and at Skutterud in Norway. It is also found at Querbach in Silesia, 
 Siegen in Westphalia, and several localities in Cornwall. This species and smaltine 
 afford the greatest part of the smalt of commerce. The most productive mines are 
 those of Vena in Sweden. (Dana, ii. 58.) 
 
 CQBAXiT-IWXCA. Syn. with COBAXT-BLOOM. 
 COBALT-PYRITES. See COBALT, SULPHIDES OF (p. 1050). 
 
 COBALT-VITRIOL Bieberite, Eed Cobalt, Bhodalosc. Hydrated native sul- 
 phate of cobalt, of somewhat variable constitution, found in stalactites, and crusts 
 investing other minerals, in the rubbish of old mines at Bieber near Hanau, and at 
 Leogang in Salzburg. It is translucent, with flesh-red or rose-red colour and vitreous 
 lustre. A specimen analysed by Winkelblech (Ann. Ch. Pharm. xiii. 265), after 
 being freed by solution and filtration from admixed manganous arsenate, yielded 
 29-05 SO 3 , 19-91 Co 2 0, 3-87 Mg 2 and 46'83 water, agreeing nearly with the formula 
 (Co 6 Mg*).(S0 4 ) 4 . .+ 28 aq. 
 
 COaAZiT-YEIiIiOW. This compound, discovered by Saint- Evre in 1852 
 (Ann. Ch. Phys. [3] xxxviii. 177), and further examined by A. Stromeyer (Ann. 
 Ch. Pharm. xcyi, 218), is produced by the action of nitrite of potassium on cobaltous 
 salts. Saint-Evre regards it as a compound of peroxide of nitrogen with cobaltous 
 oxide and potash, CoO.KO.2NO* or CoKO.(N0 2 ) a : 
 
 CoNO 3 + 2HN0 3 + 4KN0 2 = CoKO.(NO ? ) 2 + 3KN0 3 + 2NO + H 2 
 
 Nitrate of Nitric Nitrite of Cobalt-yellow. Nitrate of Nitric 
 
 cobalt. acid. potassium. potassium. oxide. 
 
 Stromeyer on. the other hand regards it as a basic potassio-cobaltic nitrite, 
 Co 2 3 .3K0.5N0 3 , or /Qg ///\2 K 6 !^"' on wn ^ cn supposition its formation may be re- 
 presented by the equation : 
 
 Nitrate of Nitrite of Cobalt- Nitrate of 
 
 cobalt. potassium. yellow. potassium. 
 
 The compound is prepared : 1. By adding an alkaline solution of nitrite of potas- 
 sium (obtained by passing the nitrous vapours evolved from a mixture of nitrate of 
 potassium and starch into caustic potash) to an acid solution of nitrate of cobalt. 
 2. By adding potash, not in excess, to a solution of nitrate of cobalt, so as to throw down 
 a blue basic salt (p. 1043), treating this with a slight excess of nitrite of potassium, 
 and adding nitric acid in a thin stream from a pipette. 3. By treating nitrate of cobalt 
 with a slight excess of potash, so as to throw down the rose-coloured hydrate, and 
 passing nitric oxide gas into the mixture. It forms a bright yellow crystalline powder 
 composed of microscopic four-sided needles with pyramidal summits. It is insoluble 
 in cold water, also in alcohol and ether, but when boiled with water, it gradually 
 dissolves, with evolution of acid vapours, and the solution, if subsequently evaporated, 
 yields a lemon-yellow salt of different composition. Nitric acid and hydrochloric acid 
 do not act upon it in the cold, but decompose it at the boiling heat, with evolution of 
 nitrous vapours. Sulphydric acid decomposes it very slowly, sulphide of ammonium 
 immediately forming black sulphide of cobalt ; when heated, it assumes an orange- 
 
COCA COCAINE. 1059 
 
 yellow colour, gives off water and afterwards nitrous fumes, and leaves sesquioxide of 
 cobalt mixed with nitrate of potassium. 
 
 Cobalt-yellow forms an excellent pigment for artistic purposes, having a beautiful 
 colour, like that of sulphide of cadmium, great permanence, and mixing easily with 
 other colours. Its formation affords also an excellent method of separating cobalt 
 from other metals, especially from nickel (p. 1046). 
 
 When a solution of lead is mixed with nitrite of potassium and acetic acid, the 
 liquid assumes a yellow colour, but no precipitation takes place ; but on adding a 
 cobalt-salt, a yellowish-green precipitate (brownish-black and crystalline from dilute 
 solutions) is formed, whose composition is that of the yellow cobalt-compound, having 
 half the potassium replaced by lead. (Stromey er.) 
 
 COCA. The leaves of Erythroxylon Coca, a plant cultivated in the mountainous 
 districts of Peru and Bolivia, and in some parts of Brazil, are extensively used by the 
 inhabitants of those countries, and of other parts of South America, for chewing like 
 tobacco, for which purpose they are mixed with burnt lime, or the ash of a peculiar 
 plant, the Chenopodium Quinoa, according to Niemann. They possess powerful tonic 
 and sedative properties, and the practice of chewing them is said to give great power 
 of enduring fatigue, even on a scanty supply of food ; but like the use of opium, it is 
 apt to become an indispensable necessity, and ultimately produces all the baneful 
 effects of a narcotic poison, such as hallucinations and premature decay both of body 
 and of mind. The use of coca is said to prevail among ten millions of people in South 
 America, the annual consumption amounting to thirty million pounds of the dry leaves. 
 Coca leaves do not long retain their activity ; indeed they are said to become useless 
 after a year's keeping. 
 
 Coca leaves contain, according to Niemann (Arch. Pharm. [2] ciii. 120 and 291), 
 a crystallisable basic substance called cocaine, a volatile odoriferous substance, a pecu- 
 liar tannic acid, cocatannic acid, and a waxy body, coca-wax. 
 
 The volatile constituent of coca leaves has a strong tarry, almost intoxicating odour. 
 On distilling the leaves with water a slightly turbid distillate is obtained, from which 
 no oil separates ; but on saturating it with common salt and redistilling, a very small 
 quantity of a white non-crystalline substance is obtained, which is volatile, fusible, 
 lighter than water, and possesses in a very high degree the odour of the leaves. 
 
 Cocatannic acid remains in the aqueous decoction of the leaves after the cocaine 
 has been precipitated by carbonate of sodium, and is left as a brown-red amorphous 
 substance when the liquid is evaporated. Its solution is coloured deep brownish-green 
 by ferric chloride, and is precipitated by tartar emetic, or solution of white of egg, but 
 not by gelatin ; it reduces chloride of gold even in the cold. 
 
 Coca-wax is contained in the precipitate formed by lime in extract of coca leaves 
 prepared with alcoholic sulphuric acid. It contains 80'2 per cent, carbon and 13*4 
 hydrogen, agreeing with the formula C 83 H 66 2 , and with the composition of the wax 
 from grass, and of that from Syrmga, as determined by Mulder. If the precipitate be 
 exhausted with ether, the ether evaporated, and the residue repeatedly boiled with 
 alcohol, the solution on cooling deposits a wax, which is white, amorphous, very friable, 
 and becomes strongly- electric by trituration. It is insoluble in water, dissolves slowly 
 in boiling alcohol, easily in ether, sometimes, though rarely, remaining in a somewhat 
 crystalline form when the ethereal solution is evaporated. It melts at 70 C., and de- 
 composes when heated. Aqueous alkalis do not act upon it, but melting hydrate of 
 potassium decomposes and dissolves it. 
 
 The substance mixed with coca leaves, to render them fit for chewing, is called 
 Llipta. According to Niemann, it is the ash of Chenopodium Quinoa. Gad eke found 
 it in 40-0 K 2 O, 177 Na 2 0, 6'6 Mg*0, 0-2 Fe, 4'5 P 2 5 , 1-8 SO 3 , 2*5 Cl, 67 SiO 2 , 
 3-0 CO 2 , 13 '5 sand, 1*0 water, and a trace of organic matter. (Handw. d. Chem. ii. 
 [2] 123.) 
 
 COCAINE. C 1S H I9 NO' or C S2 # 19 A T 0. (Niemann, Ann. Ch. Pharm. cxiv. 213.) 
 An alkaloid obtained from coca leaves, resembling atropine in many of its properties. 
 Niemann assigns to it the formula C 32 H 20 N0 8 ; but this is improbable, because the 
 sum of the atoms of H and N is an odd number. 
 
 Cocaine is prepared by digesting coca leaves with 85 per cent, alcohol containing a 
 small quantity of sulphuric acid, mixing the expressed mass with milk of lime, neu- 
 tralising the nitrate with sulphuric acid, evaporating off the alcohol, mixing the re- 
 sidue with water, precipitating the resulting yellow-brown solution with carbonate of 
 sodium, treating the brown precipitate of impure cocaine with ether, and evaporating. 
 Cocaine then remains, partly amorphous, partly crystalline, and may be purified by re- 
 peated treatment with alcohol. 
 
 Cocaine crystallises in small, colourless, inodorous prisms ; it has a slightly bitter 
 taste, and produces temporary insensibility on the part of the tongue with which it 
 comes in contact. It w soluble in 704 pts. of water at 12 C., more soluble in alcohol, 
 
 3 Y2 
 
1060 COCATANNIC ACID COCHINEAL. 
 
 and still more in ether. It melts at 98 C., and solidifies to a transparent mass, which 
 gradually becomes white and crystalline. At a higher temperature, a very small por- 
 tion appears to volatilise undecomposed, but the greater part is decomposed, yielding 
 ammoniacal products. Cocaine dissolves without colour in strong nitric, hydrochloric, 
 and sulphuric acid, the last solution only becoming black when heated. 
 
 Cocaine is strongly alkaline ; it dissolves in dilute acids, and neutralises them com- 
 pletely. Its salts do not crystallise readily, the hydrochlorate, however, more easily 
 than the others. Solutions of cocaine-salts yield with caustic alkalis, a white precipi- 
 tate soluble only in a large excess of fixed alkali, more soluble in ammonia. Carbo- 
 nate of sodium forms a precipitate insoluble in excess. Carbonate of ammonium, a 
 precipitate easily soluble in excess. Acid carbonate of potassium and phosphate of 
 sodium produce a red precipitate. Sulphocyanide of potassium produces but a slight 
 turbidity ; picric acid forms a sulphur-yellow precipitate, which gradually aggregates 
 into resinous lumps ; tannic acid, on addition of hydrochloric acid, forms a white pre- 
 cipitate, which aggregates in a similar manner ; mercuric chloride and potassio-mcr- 
 curic iodide produces white precipitates ; iodine-water & kermes-brown; iodide vf potas- 
 sium containing iodine, a dark-brown precipitate ; trichloride of gold and dichloride of 
 platinum yield precipitates with the hydrochlorate ; protochloride of tin produces a 
 white precipitate, even in slightly acid and dilute solutions. 
 
 In most of these reactions, cocaine closely resembles atropine (i. 474) ; the latter, 
 however, is not precipitated by carbonate of ammonia, or in acid solutions by stannous 
 chloride ; the two bases differ also in their reactions with gold and platinum-salts, and 
 in their melting points, that of cocaine being 6 C. higher than that of atropine. 
 
 Hydrochlorate of Coca'ine crystallises in white slender needles, easily soluble 
 in water; it has a bitter taste and produces on the tongue the peculiar action of the 
 base itself, but in a higher degree. The solution, even when very dilute, is precipi- 
 tated by chloride of gold, yielding the compound C I6 H 19 N0 4 .HCl.AuCl 3 , which crys- 
 tallises from alcohol in gold-yellow scales or laminae. This gold-salt melts when 
 heated, and then yields a sublimate of benzoic acid, affording a very characteristic 
 reaction. The chloroplatinate is a yellow-brown flocculent precipitate, which soon 
 becomes crystalline, and is nearly insoluble in hydrochloric acid. 
 
 Acetate of Co ca'i ne crystallises readily ; the nitrate with difficulty. The sul- 
 phate remains when its solution is evaporated, as a colourless varnish-like mass, which 
 becomes crystalline after a while ; it is permanent in the air. 
 
 COCATAXfTXTXC ACID. COCA-WAX. See COCA (p. 1059). 
 
 COCCXBT. A peculiar nitrogenous substance existing, according to Pelletier and 
 Caveutou, in cochineal, and forming, as it were, the fles'h of the insect ; it resembles 
 gelatin in some of its characters, albumin and fibrin in others. 
 
 COCCXSTITXi. Haidinger's name for the reddish-brown mineral, with adaman 
 tine lustre, from Casas Viejas in Mexico, which Del Rio regards as mercuric iodide. 
 It melts and sublimes with facility. 
 
 COCCIK UIC ACID. A volatile fatty acid existing, according to Pelletier and 
 Caventou, in cochineal. 
 
 COCCIWONTIC ACID. A derivative of euxanthic acid (p. 712). 
 
 COCCODEA VTRIDIS. This plant contains a green colouring matter differing 
 from chlorophyll. (Salm-Horstmar, Pogg. Ann. xciv. 466; cxv. 176.) 
 
 COCCOGNTC ACID. An acid contained, according to Gobel (Buchn. Eepert. 
 viii. 203), in the seeds of Daphne Gnidium. It is dissolved by water fz-om the alco- 
 holic extract; crystallises in colourless, slightly acid prisms; does not precipitate lime- 
 water, or the solutions of chloride of barium, acetate of lead, or ferrous sulphate. 
 
 COCCOLITE. A name applied to certain granular varieties of augite. 
 
 COCCOliOBA UVIFERA. The plant which yields American kino. 
 
 COCCOXXir. Syn. with PICROTOXIN. 
 
 COCCTTIiUS ZHTDICTTS. Grains of Paradise. The fruit of the Cocculus subc 
 rosus (Dec.), Menispermum cocculus (Linn.), Anamirta cocculus (Wight and Ar- 
 nott). It possesses strong narcotic and poisonous properties, due to the presence of u 
 bitter substance, picrotoxin (C 5 H 6 2 ), of which it contains about ^ o f its weight. 
 It is used to adulterate beer, and is sometimes thrown into water to intoxicate or kill 
 fish; it is occasionally employed in medicine. (See Ure's Dictionary of Arts, Manu- 
 factures and Mines, i. 786 ; also the article BEER in this Dictionary, i. 537.) 
 
 COCCTJSIC ACID, C 8 H 8 3 , is the acid corresponding to nitrococcusic acid, 
 a product of the action of nitric acid on carmine (i. 804) ; it has not yet been obtained 
 in the separate state. 
 
 COCHINEAXi. Cochenille, Coccionella. Several insects of the genus Coccus, es- 
 pecially the Coccus cacti or cochineal insect, yield a splendid colouring matter, exten- 
 
COCHINEAL. 1061 
 
 sively used for dyeing and the preparation of pigments. The cochineal insect lives on 
 various plants of the genus Opuntia, especially on the nopal, Opuntia decumana, 
 O. cactus, and 0. monacantha. It is a native of Mexico, but its cultivation has been 
 introduced into many other hot countries, namely, the West Indies, Teneriffe, Ma- 
 deira, Algeria, Java : in colder climates it does not thrive. The female insects only are 
 collected; they are, killed either by dry ing in the sun, on hot plates, or in stoves, or by 
 immersing them for a short time in hot water. The last method yields a cochineal of 
 somewhat red-brown aspect, whereas if the insects have been killed by drying, it has 
 more of a blackish or ash-grey colour, with a silvery surface ; the latter is preferred. 
 The dry cochineal is freed from dust and adhering impurity by shaking it in sacks ; 
 the fine dust is then removed by sifting, and the larger and smaller lumps in the re- 
 maining mass are separately sorted. 
 
 Other species of coccus probably contain the same colouring matter, but in smaller 
 quantity and more contaminated with foreign substances. 
 
 Cochineal occurs in commerce in nearly egg-shaped grains 1 or 2 lines long, somewhat 
 hollowed below and arched above, about 70,000 going to the pound. It is inodorous, 
 very friable, and contains within it a dark red granular mass, which yields a powder of 
 a fine deep red colour ; it has a bitter, slightly astringent taste, and leaves but a small 
 quantity of ash when burnt. In water, it swells up considerably, the shape of the 
 insect and its three pairs of legs then becoming distinctly visible. 
 
 The first investigation of cochineal was made by John (Chemical Tables, p. 127), 
 who found in it 50 per cent, coccus-red (carmine), 10 waxy fat, 1/5 inorganic salts 
 (chlorides of potassium and ammonium, and phosphates of calcium, iron, and magnesium), 
 28'0 animal matter, and 10'5 water. According to Pelletier andCaventou (Ann. Ch. 
 Phys. vii. 90; viii. 255), it contains a peculiar nitrogenous matter, coccin ( p. 54), 
 which forms, as it were, the flesh of the insect, and an acid, not examined, to which 
 they give the name of coccinic acid. 
 
 The colouring matter of cochineal iscarminic acid(i. 804). 
 
 The watery extract likewise contains a crystallisable nitrogenous substance, 
 C 9 H. n N0 3 , homologous with tyrosine, (C 8 H 9 N0 3 ), and very similar to it in appearance 
 and reactions. It remains in the aqueous decoction of cochineal after the carminic 
 acid has been precipitated by acidulated acetate of lead, and may be separated by re- 
 moving the excess of lead from the filtrate with sulphuretted hydrogen, and evapo- 
 rating to a syrup ; it then separates in a crystalline mass, and an additional quantity 
 may be obtained by further concentration. It is insoluble in alcohol and ether, soluble 
 without decomposition in hydrochloric acid, decomposed by strong nitric acid, the 
 liquid yielding crystals of a new acid on evaporation ; hot nitric acid produces a more 
 thorough decomposition, with separation of charcoal. The chalky substance dissolves 
 in alkalis, and is separated therefrom by acids. It does not appear to form definite 
 compounds either with acids or with bases. 
 
 The mother-liquor from which the whole of the chalky substance has been removed, 
 dries up to a soft mass amounting to 10 or 12 per cent, of the cochineal ; part of this 
 mass is soluble in alcohol, the remainder in water. 
 
 Cochineal boiled with water yields a deep red liquid, which assumes a reddish-yel- 
 low colour when mixed with tincture of galls or with strong acids, and a beautiful 
 violet with lime-water ; it is precipitated violet-blue by neutral acetate of lead, bright 
 red by ammonia, dark black-brown "by ferric chloride ; olive-green by a larger quantity, 
 deep red by alum. After the cochineal has been thoroughly boiled with water, a 
 brownish animal substance remains. 
 
 The red colour of cochineal is likewise extracted by alcohol. 
 
 The chief use of cochineal is for the preparation of carmine and carmine-lakes 
 (i. 804). It is likewise employed for dyeing wool and silk scarlet (the fabric being 
 steeped first in annotto, then in a decoction of cochineal containing cream of tartar and 
 stannoso-stannic chloride), or crimson (cochineal with tartar and tin-salt). Cochi- 
 neal is likewise used for the preparation of rouge, of painters' colours, and of red ink, 
 and for colouring tooth-powder, confectionery, liqueurs, &c. 
 
 Cochineal varies much in colouring power, according to its source and mode of 
 preparation. The relative quantities of colouring matter in different samples may 
 be estimated approximately by the depth of colour of a solution obtained by heating 
 1 gramme of cochineal in the water-bath for an hour, with 1000 grammes of water 
 and 20 drops of a saturated solution of alum ; also by the depth of colour which the 
 same extract will impart to wool. Eobiquet estimated the amount of colouring 
 matter by means of a graduated solution of chlorine ; Anthon by a graduated solution 
 of an alumina-salt. 
 
 A better method is that of Penny, depending on the action of ferricyanide of 
 potassium. 1 gramme of cochineal is extracted with 50 cub. cent, of dilute potash- 
 solution; the extract is further diluted with 100 cc. of cold water; and the purple 
 
1062 COCHINEAL-RED COCKLE ARIA. 
 
 solution thereby obtained is mixed, when cold, with a graduated solution of ferrieyanide 
 of potassium (1 grm. of the salt to 200 cc. of solution), till its colour changes to dark 
 brown. All these methods yield only relative results for comparing different sorts of 
 cochineal one with the other. (See Ure's Dictionary of Arts, Manufactures and Mines 
 i. 786 ; Handw. d. Chem. 2" Aufl. ii. [2] 127.) 
 
 COCHINEAIi-RED is properly carmine ; the same term is, however, applied to 
 a splendid red artificial colour, which contains a considerable quantity of arsenate of 
 aluminium, and is therefore highly poisonous. 
 
 COCHXiCARXA. A genus of cruciferous plants, including horse-radish and 
 scurvy- grass, distinguished by their acridity, arising from the presence of volatile 
 oils, similar to, or identical with, volatile oil of mustard (sulphocyanate of allyl). 
 
 Cochlcaria Armoracia. Horse-radish. The volatile oil of this plant, M r hen 
 purified, is identical with oil of mustard. It appears to exist in the root ready formed, 
 and may be obtained by bruising the root to a pulp, and distilling it per se. The 
 best mode of preparation, however, is to distil 3 pts. of the finely chopped root with 
 2 pts. water, in a glass vessel (if a copper still be used, only a small quantity of oil is 
 obtained, in consequence of the formation of metallic sulphide). 100 pts. of the root 
 thus treated yield about 0*05 pt. of crude oil, which may be purified by rectification 
 with water and drying over chloride of calcium. The purified oil is colourless or pale 
 yellow; has a density of I'Ol ; smells like oil of mustard, and contains 48-41 per. cent. C, 
 and 5-26 H (sulphocyanate of allyl, C 3 H 5 .CNS, requires 48-49 C and 5 -05 H). 
 The crude oil is light yellow, of the consistence of cinnamon-oil, heavier than water, 
 evaporates quickly, has an intolerable odour of horse-radish, tastes sweet at first, 
 afterwards sharp and burning, and inflames the lips and tongue. When kept under 
 water for a year, it disappears, and silvery needles are formed, which smell like horse- 
 radish, excite irritation in the throat, melt and volatilise when heated, and dissolve 
 but slowly in alcohol. Oil of horse-radish is decomposed by nitric acid, sulphuric 
 acid, and chlorine. It yields sinapoline with oxide of lead, and thiosinnamine with 
 ammonia. It dissolves slightly in water, the solution forming a brown precipitate 
 with acetate of lead, black with nitrate of silver. It dissolves readily in alcohol 
 (Gm. x. 55). 
 
 Cochlearia officinalis. Common scurvy grass. The herb of this plant con- 
 tains 92'2 per cent, water, and yields 1-6 per cent, ash, which, according to Greisek-r, 
 is very rich in potash, but, according to Braconnot, contains soda. The base is partly 
 combined with nitric acid and, according to Braconnot, with an organic acid resembling 
 malic acid. 
 
 Oil of scurvy -grass, Oleum coehlearice, obtained by distilling the herb with 
 water, is yellow, pungent, of specific gravity 0'942 (Geiseler), boils between 156 
 and 159 C. (Simon). It dissolves easily in alcohol, and the alcoholic solution, 
 Spiritus cockleari(8, may be obtained by distilling the bruised herb with alcohol. 
 According to Geiseler (Arch. Pharm. cxlvii. 136, 257), the oil is an oxysulphide of 
 allyl, CPffSO, and yields with ammonia a crystalline compound, C*H 5 SO.NH 3 . 
 [These formulse are doubtful.] The oil does not exist ready formed in the plant, but 
 is produced by the action of myrosin in presence of water, on a peculiar substance exist- 
 ing therein. According to Winckler (Jahrb. pr. Pharm. xviii. 319), this substance is 
 neutral, and is converted into the volatile oil by the joint action of myrosin and lime. 
 
 Scurvy-grass camphor, or Cochlearin, C 6 H 7 2 (?), is a crystalline substance 
 sometimes deposited from Spiritus cochlearice, and from the water which has been 
 distilled off the plant. It forms small, nacreous, shining laminae or needles, having a 
 faint odour, and sharp aromatic taste. Specific gravity = 1*248. It melts at 45 C., 
 sublimes without alteration, dissolves lightly in pure water, easily in water containing 
 carbonate of potassium, also in alcohol and ether. (Maurach, Eepert. Pharro. xcix. 128.) 
 
 Cochlearia Drab a, Whitlow Pepperwort, yields, by distillation with water, a 
 volatile oil, similar to that obtained from radish-seeds. (Pless, Ann. Ch. Pharm. Iviii. 40.) 
 
 Cochlearia anglica. English scurvy-grass. The fresh herb of this plant con- 
 tains, according to T. J. Herapath (Chem. Soc. Qu. J. ii. 4), 2-42 per cent, ash ; the 
 dry herb 21-1 per cent, ash ; of which 78 '1 per cent, are soluble, and 21'9 per cent, in- 
 soluble in water. 100 parts of the ash contain : 
 
 Soluble in Water. 
 
 Potash 0-1 
 
 Soda 7-7 
 
 Carbonic acid (CO 2 ) 3-6 
 
 Sulphuric acid (SO 3 ) 3-1 
 
 Chloride of sodium . .63-6 
 
 Insoluble in Water. 
 
 Carbonate of calcium .... 7-2 
 Carbonate of magnesium . . . 1*3 
 Phosphate of calcium . . . .10-3 
 
 Ferric phosphate O'G 
 
 Silica .... ,2-5 
 
COCHLEARIN COCOA-NUT OIL. 1063 
 
 See COCHLEARIA OFFICINALIS. 
 COCZHrZG ACID. Cocostearic acid. Cocylic acid. Coconustalgsdure. A fatty 
 acid, or probably a mixture of acids, obtained from cocoa-nut oil. 
 
 Bromeis (Ann. Ch. Pharm. xxxv. 277), by saponifying cocoa-nut fat, decomposing 
 the soap with an acid in the usual way, pressing the resulting fatty acid between paper, 
 and recrystallising from alcohol, obtained a nearly inodorous fatty acid, which melted at 
 35 C., solidified to a porcelain-like mass translucent at the edges, and distilled without 
 decomposition. Saint-Evre (Ann. Ch. Phys. [3] xx. 95) decomposes the soda-soap 
 of cocoa-nut oil with acetate of lead ; exhausts the lead-soap with ether; decomposes 
 the undissolved soap with an acid ; and crystallises the fatty acid from alcohol. From 
 a saturated solution in aqueous alcohol, it crystallises, on cooling, in needles; but 
 from a solution in strong alcohol, by evaporation, in amorphous masses. It melts at 
 34-5 C., and volatilises without decomposition only in a stream of gas. 
 
 Bromeis assigned to his cocinic acid the formula C'- 7 H 27 0\ but his analysis, calculated 
 according to the more recently determined atomic weight of carbon (C = 6) gives 
 rather O- 6 H 26 4 , or C 13 H 26 2 . Heintz has since announced the separation of an acid 
 of the same composition from spermaceti. Fehling obtained from cocoa-nut oil an acid 
 resembling the acid prepared by Bromeis in appearance and melting point, and corre- 
 sponding, exactly to the formula C 13 H 26 2 . 
 
 Saint-Evre, on the other hand, assigned to the cocinic acid which he obtained, the 
 formula C n H 22 2 , though it agrees very closely with that of Bromeis in the melting 
 point. 
 
 Heintz regards the acid C 13 H 86 2 from cocoa-nut oil, and likewise that obtained by 
 himself from spermaceti, as a mixture, especially on account of its melting point, which 
 is lower than that of lauric acid (C I2 H 24 2 ) ; whereas if it were really a definite acid, 
 its melting point would be intermediate between those of lauric acid (44 C.) and 
 myristic acid, C 14 H a 2 (54 C.). He finds, indeed, ,that a mixture of 14 pts. lauric and 
 2 pts. myristic acid melts at about 35 C. Saint-Evre's formula, CM'H^O 2 , is on this 
 account more probable. 
 
 Cocinate of barium, crystallised from boiling alcohol, is, according to Bromeis 
 C 13 H 25 Ba0 2 . Cocinate of silver, C l *IP*AgO* (Bromeis), C"H 21 Ag0 2 (Saint-Evre), is 
 obtained by precipitation from alcoholic solutions, in white flocks melting at 55 C., 
 soluble in ether, sparingly soluble in alcohol. 
 
 Cocinate of ethyl, C 13 H 25 (C 2 H 5 )0 2 or C n H 21 (C 8 H 5 )0 2 , obtained by passing hydro- 
 chloric acid gas into a hot alcoholic solution of cocinic acid, washing the product with 
 weak alkali, and drying over chloride of calcium, is a liquid having a faint-yellow 
 colour, a very pungent odour of apples, and a sweet mawkish taste. 
 
 COCININ. Cocinate of glyceryl. The name of the neutral fat corresponding to 
 cocinic acid. The separate identity of such a fat, like that of the acid itself, must, for 
 the present be considered doubtful. Brandes (Ann. Ch. Pharm. xv. 115), by ex- 
 pressing the fat from cocoa-nuts, and crystallising it repeatedly from boiling alcohol, 
 obtained a snow-white laminar crystalline fat, of specific gravity 0'92 at 8 C., less 
 soluble in pure than in common ether, soluble in 40 pts. absolute alcohol at 20 C., 
 about 12 pts. at 44 C., sparingly soluble in aqueous alcohol of 075 in the cold, more 
 soluble in the same when warm ; crystallising on cooling ; decomposed by dry dis- 
 tillation. 
 
 COCINOWE. A product of the decomposition of neutral cocinate of calcium, 
 consisting, according ,to Delffs (Pogg. Ann. Ixxxvi. 587), of C 21 H 4v O, and therefore 
 the acetone of Saint-Evre's cocinic acid C U H 22 2 . When purified by recrystallisation 
 from boiling alcohol, it forms colourless, inodorous, tasteless laminse, melting at 38 C., 
 and boiling at a temperature beyond the range of the mercurial thermometer. 
 
 COCOA-NUT Oil.. This oil or fat is obtained by pressure from the fruit of 
 certain cocoa-palms, Cocos nucifera, C. butyracca, &c., and is imported in large quantities 
 into Europe for the manufacture of soap. It is whitish, of unctuous consistence, with 
 a peculiar disagreeable odour of volatile fatty acids, and a mild taste ; it melts at 20 C., 
 dissolves with aid of heat in alcohol and ether, readily in oils, both fixed and volatile, 
 benzene, &c. 
 
 Cocoa-nut oil quickly becomes rancid, and is easily saponified. It is a mixture of 
 several glycerides, containing also free fatty acids. By saponification it yields both 
 fixed and volatile fatty acids. The volatile acids, which may be separated by dis- 
 tilling the mixture of free fatty acids with water, consist chiefly of caprylic acid mixed 
 with small quantities of caproic and capric acids. The fixed fatty acids of cocoa-nut 
 oil are partly liquid at ordinary temperatures, partly solid. The former have not been 
 particularly examined ; of the latter, several may be isolated by crystallisation from 
 alcohol, viz. lauric acid, C 12 H 84 2 , which maybe obtained pare, with the melting 
 point 43 C., by fractional precipitation of the soda soap (0 tide mans, J. pr. Chem. 
 
1064 CODEINE. 
 
 Ixxxi. 367) ; the acid, C^'H^O 8 , which was obtained from the oil by Saint- lvre, and 
 C 13 H 26 2 by Bromeis, (see COCINIC ACID, p. 67); myristic acid, C M H M 2 , like- 
 wise exists in considerable quantity in cocoa-nut oil. The acid actually obtained had 
 very nearly the composition of myristic acid, and melted at 49 C., the melting point of 
 the pure acid being 53'8 (Fehling, Ann. Ch. Pharm. liii. 399). Gorgey (ibid. 
 civ. 25) likewise found a fatty acid, C 15 H 30 2 , melting at 56 C., which, from the ex- 
 amination of the silver-salt, he regarded as a mixture of myristic and palmitic acids. 
 Fehling also found pure palmitic acid. Stearic acid is probably present in small 
 quantity. 
 
 The solid fats of cocoa-nut oil are separated from the more liquid fats by pressure, 
 and used for the manufacture of candles. 
 
 The solid fatty acids of cocoa-nut oil are converted, by prolonged treatment with 
 nitric acid, into a mixture of acids of the series C n H 2n ~ 4 4 , viz. anchoic, suberic, 
 pimelic, adipic, succinic acid, and an oily mass containing nitrocapric and nitrocaprylic 
 acids. 
 
 CODEINE. C 18 H 2 'N0 3 + H 2 or C 36 H"NO? + 2HO.A non-volatile organic base 
 contained in opium. It was discovered by Robiquet in 1832 (Ann. Ch. Phys. [2] li. 
 259), and has been further examined by Couerbe (ibid. lix. 158), Regnault (ibid. 
 Ixviii. 136), Gregory (Ann. Ch. Pharm. xxvi. 44), Will (ibid. 44), Gerhardt (Rev. 
 Scient.x.203; Traite, iv. 40), and especially by Anders on (Ed. Phil. Trans, xx. [1] 57). 
 
 Preparation. 1. The aqueous infusion of opium, evaporated to a syrup, is mixed 
 with solution of chloride of calcium ; the mass is diluted with water ; the resulting 
 meconate of calcium is separated, washed several times with small quantities of water 
 and pressed ; and the liquid thus obtained is evaporated, lumps of marble being thrown 
 into it to neutralise the free acid. Fresh quantities of meconate of calcium then 
 separate, and the decanted liquid, if left at rest, deposits crystals of hydrochlorate of 
 morphine and hydrochlorate of codeine. These crystals are dissolved in water, and 
 the solution, after purification with animal charcoal, is precipitated by ammonia, 
 which separates the greater part of the morphine, leaving the codeine in solution. The 
 filtered liquid is evaporated over the water-bath to expel the excess of ammonia, the 
 morphine salt remaining in solution being at the same time precipitated ; the saline 
 solution is concentrated and precipitated by caustic potash ; and the precipitate of 
 codeine is washed, dried, and dissolved in ether, whence it is deposited in crystals. 
 (Robiquet.) 
 
 2. To obtain the whole of the codeine from the mother-liquor which remains after 
 the morphine has been removed by precipitation with ammonia, as just described, it 
 is necessary to get rid of the sal-ammoniac with which it is mixed. This may be 
 effected by repeatedly concentrating the liquid the greater part of the hydrochlorate 
 of codeine then separating out, while the sal-ammoniac remains dissolved and decom- 
 posing the remaining sal-ammoniac with caustic potash. By repeating the crystallisa- 
 tion a certain number of times, the hydrochlorate of codeine might be obtained quite 
 free from sal-ammoniac; this, however, would occasion the loss of a considerable 
 quantity of codeine, inasmuch as the two hydrochlorates do not differ greatly in solu- 
 bility ; but if the crystallisation be discontinued at an earlier stage, the greater part 
 of the sal-ammoniac may be removed without loss of codeine. The crystals of hydro- 
 chlorate of codeine are then to be dissolved in boiling water, and a strong solution of 
 caustic potash added in excess, which will precipitate the codeine, partly as an oil which 
 gradually solidifies, partly in the crystalline state as the liquid cools. The mother- 
 liquor yields by evaporation a fresh crop of crystals of codeine, and lastly, after reduc- 
 tion to a very small bulk, it becomes filled, on cooling, with long silky needles of 
 morphine, which had been retained in solution by the excess of potash. (Anderson.) 
 
 3. Opium is exhausted with cold water, the morphine precipitated by ammonia, the 
 meconic acid by chloride of calcium, and the colouring matter by subacetate of lead. 
 The liquid filtered from the lead-precipitate is freed from lead by sulphuric acid and 
 filtered again ; the filtrate is mixed with excess of potash ; the mixture left to stand 
 in the air till carbonate of potassium has formed ; and the whole agitated with ether, 
 which extracts the codeine. (Winckler, Repert. Pharm. xliv. 459.) 
 
 4. Merck (Ann. Ch. Pharm. xi. 279) precipitates the mixture of the hydrochlorates 
 of codeine and morphine with pure soda ; treats the precipitate with cold alcohol ; 
 saturates the alcoholic solution with sulphuric acid ; removes the alcohol by distillation, 
 and adds cold water to the remaining liquid as long as it produces turbidity ; then 
 filters, evaporates to a syrup, and agitates the residue with excess of potash and with 
 ether. The codeine dissolves in the ether and is deposited by spontaneous evapora- 
 tion ; it is finally treated with alcohol, to free it from an oily substance which prevents 
 crystallisation. 
 
 Purification. Impure crystals of codeine are purified by dissolving them in hydro- 
 chloric acid, boiling with animal charcoal, reprecipitating with caustic potash, and. 
 
CODEINE. 1065 
 
 finally dissolving the precipitate in ether containing water, in order to free the codeine 
 from the last trace of morphine ; the ether used must, however, be free from alcohol, 
 otherwise a syrupy liquid remains, on evaporation, which cannot be made to crystallise. 
 If anhydrous ether be used, the codeine dissolves much more slowly (Handw. d. Chem. 
 ii. [3] 136). 100 pounds of opium yield from 6 to 8 oz. of codeine (Eobiquet). The 
 proportion of codeine in opium is from i to -^ of that of the morphine. (Anderson.) 
 
 Properties. Codeine crystallises from anhydrous ether in small anhydrous rect- 
 angular octahedrons, truncated and modified in various ways. From hydrated ether 
 or alcohol, and from water, it separates in hydrated crystals of the trimetric system. 
 Those deposited from alcohol exhibit the combination ooP . OP . Poo . Poo ; those 
 from water, the combination ooP . 00 . |f*oo. Inclination of ooP : ooP = 87 40'; 
 Poo : OP = 141 37'; Poo : OP = 140 23'; |Poo : OP = 157 25'. Cleavage pa- 
 rallel to OP. (Kopp, Krystallographie, 266.) 
 
 Codeine dissolves in water much more readily than morphine, especially in boiling 
 water. 100 pts. of water at 15 C. dissolve 1'26 pts. codeine, When heated with a 
 quantity of water less than sufficient to dissolve it, it melts to an oily mass, which 
 remains at the bottom of the liquid. It dissolves easily in alcohol and hydrated ether, 
 less easily in anhydrous ether. The alcoholic solution deflects the plane of polarisation 
 of a luminous ray strongly to the left; [a] = 118*2 ; acids have scarcely any effect 
 on the rotatory power. 
 
 Codeine is quite insoluble in potash ; it dissolves in ammonia, but not to a greater 
 extent than in pure water. 
 
 Anhydrous codeine contains : 
 
 Robiquet. Couerbe. Regnault. Gregory. Will. Anderson. 
 
 Calculated. (mean.) (mean.) (mean.) 
 
 Ci . . . 216 72-24 70-36 71 '84 73'31 73'05 73'27 72-01 
 
 H2i . . . 21 7-02 7'58 7'37 7'19 7'21 7'25 7'09 
 
 N . . .14 4-68 5-35 4-89 4-89 4-50 
 
 O 3 . . . 48 16-06 
 
 299 100-00 
 
 The hydrated crystals contain, according to Gerhardt's analysis, 67*82 per cent. C, 
 and 7*46 H, agreeing nearly with the formula C 18 H 2I N0 3 + IPO, which requires 
 68-13 C, 7-25 H, 4-41 N, and 20-21 0. 
 
 Codeine is a strong base, quickly restoring the blue colour of reddened litmus, and 
 precipitating the salts of lead, iron, copper, cobalt, nickel, &c. 
 
 In its action on the animal economy, codeine resembles morphine in many respects. 
 According to Kobiquet, doses of 0'02 to 0'03 grm. produce in 24 hours, especially in 
 excitable persons, a sensation of comfort and repose, and a refreshing sleep, whereas 
 doses of 0*15 to 0*12 grm. produce heavy sleep, with a feeling of intoxication after 
 waking sometimes also nausea and vomiting ; more than 0*2 grm. cannot be taken 
 in 24 hours without danger of serious consequences. 
 
 Codeine is said to be sometimes adulterated with sugar-candy ; this impurity may 
 be detected by its greater solubility in water, its smaller solubility in alcohol, and its 
 very different action on polarised light. According to Robiquet, a solution of 0*500 grm. 
 pure codeine in 100 cub. cent, alcohol of at least 56 per cent, gives, for the transition 
 tint, a deflection of 11 to the left. 
 
 . Decompositions. 1. When codeine is dissolved in excess of sulphuric acid of medium 
 strength, and the solution is digested in a sand-bath, it acquires a dark colour, and 
 after a while yields a precipitate with carbonate of sodium, which is not the case with 
 codeine-salts in their ordinary state. The precipitate thus formed consists of amor- 
 phous codeine, which, after washing with water, solution in alcohol, and precipi- 
 tation by water, forms a grey powder with more or less green reflection, insoluble in 
 water, easily soluble in alcohol, and precipitated therefrom by ether. It melts at 100 C. 
 to a black resinous mass. It dissolves easily in acids, forming amorphous salts, which 
 dry up by evaporation to brown resins. If the action of the sulphuric acid on the 
 codeine be prolonged, a dark green substance is obtained. 
 
 2. Nitric acid, according to its degree of concentration, forms with codeine either a 
 basylous nitro-compound (p. 1067), or a yellow resin soluble in alkalis. 
 
 3. Chlorine and bromine form substitution-products (p. 1065). 
 
 4. Iodide of ethyl heated with codeine forms hydriodate of ethyl-codeine. 
 
 _ 5. Codeine gently heated with hydrate of potassium, yields several volatile alkalis, 
 viz. ammonia, methylamine and tritylamine, in variable proportion, according to the 
 manner in which the process is conducted. A volatile crystalline base is likewise 
 produced in small quantity, and a brown or black substance remains. 
 
 SALTS OF CODEINE. Codeine is a mono-acid base, dissolving readily in acids, 
 and yielding for the most part crystallisable salts. They are very bitter, are not 
 reddened by nitric acid, and do not impart a blue colour to ferric salts. Potash pre- 
 
1066 CODEINE. 
 
 cipitates codeine from their solutions; ammonia does not precipitate them imme- 
 diately, but gives rise, after some time, to the separation of small transparent crystals 
 of codeine. Infusion of gall-nuts precipitates codeine-salts immediately. 
 
 Chr ornate of Codeine is easily obtained in beautiful yellow needles. 
 
 Hydrochlorate of Codeine, C 18 H 2I N0 3 .HC1 + 2H 2 0. A somewhat concentrated 
 solution of codeine in hydrochloric acid, solidifies completely on cooling ; a more dilute 
 solution deposits radiate groups of short needles, exhibiting under the microscope the 
 form of prisms with four faces, terminated by dihedral summits. The crystals dissolve 
 in 20 pts. of water at 15 4 5C., and in less than their weight of boiling water. They 
 give off \ of their water at 100 C., the remainder at 121, part of the acid, however, 
 going off at the same time. 
 
 Chloro-aurate of Codeine, obtained by mixing the solutions of the component salts, 
 is a reddish or light-brown precipitate, moderately soluble in hydrochloric acid. 
 
 The Chloromereurate is obtained in like manner, as a precipitate, soluble in boiling 
 water and in alcohol, and deposited in stellate groups on cooling. 
 
 The CMoroplatinate, C 18 H 81 N0 3 .HCl.PtCl 2 + 2H 2 O separates on adding dichloride of 
 platinum to a moderately concentrated solution of hydrochlorate of codeine, as a light- 
 yellow powder, which, if left in the liquid or kept moist on the filter, gradually becomes 
 crystalline, and of an orange-red colour. From very dilute solutions, the double salt 
 separates after some time in silky needles. It dissolves sparingly in cold water, and 
 is decomposed by boiling water. It gives off f of its water at 100 C., the rest at 120, 
 with incipient decomposition. 
 
 Hydriodate of Codeine. C I8 H 21 N0 3 .HI + H 2 0. Long thin needles, soluble in 
 about 60 pts. of cold water, much more soluble in boiling water. They do not give off 
 any water at 100 C. 
 
 Hydrocyanate of Codeine is uncrystallisable. The hydroferrocyanate, produced 
 by mixing the alcoholic solutions of codeine and hydroferrocyanic acid, is a white 
 precipitate which crystallises after a while in needles, and dissolves in excess of hydro- 
 ferrocyanic acid. The hydroferricyanate produced by adding aqueous ferricyanide of 
 potassium to hydrochlorate of codeine, is a very unstable crystalline compound. 
 
 Nitrate of Codeine, C 18 H 21 N0 3 .HN0 9 , is produced by slowly adding nitric acid 
 of specific gravity 1'06 to pulverised codeine, carefully avoiding an excess of the-acid, 
 which would produce decomposition. It dissolves easily in boiling water, and separates 
 on cooling in small prismatic crystals. It melts at a moderate heat, and decomposes 
 at a higher temperature, leaving a difficultly combustible charcoal. 
 
 Oxalate of Codeine, 2C 1S H 21 N0 3 .H 8 C 2 4 + 3H'0, is deposited on cooling, from 
 a hot saturated solution in short prisms and sometimes in scales. It dissolves in 
 30 pts. water at 15'5 C., and in about half its weight of boiling water. It gives off its 
 water at 100, turns brown at about 121, and decomposes completely at higher 
 temperatures. 
 
 Phosphate of Codeine, C 18 H 2I N0 3 .H 3 P0 4 + |H 2 O A solution of ordinary phos- 
 phoric acid saturated with pulverised codeine does not crystallise by concentration, but 
 on addition of strong alcohol immediately deposits scales or short prisms. It is very 
 soluble in water. 
 
 Other phosphates of codeine appear also to exist. 
 
 Sulphate of Codeine, 2C I8 H 21 N0 3 .H 2 S0 4 + 5H 2 (or CH"NO*.HSO* + 5HO) 
 crystallises in radiate groups of long needles, or by spontaneous evaporation, in flattened 
 prisms. It dissolves in 30 pts. of cold water, and is very soluble in hot water. 
 When pure, it is neutral to test-paper ; but it is apt to retain a small quantity of acid, 
 which may be separated by repeated crystallisation. The crystals belong to the tri- 
 metric system, ooP.Pco . oof* GO. Inclination of ooP: ooP = 151 12'; oo Poo 
 Poo - 113 45' ; Poo : P oo = 133 3'; oop oo : ooP = 104 24. Cleavage parallel 
 to ooP oo. 
 
 Sulphocyanate of Codeine. C 18 H 21 N0 3 .HCyS -1- \ H 2 0. Eadiate needles melt- 
 ing at 100 C., giving off 2-45 per cent, water (= \ at.) at 100 C. 
 
 Tart rate of Codeine is uncrystallisable. 
 
 Substitution-products of Codeine. 
 
 BROMOCODEINE. 2C 18 H 20 BrN0 3 + 3H 2 (Anderson loc. czV.) Prepared by add- 
 ing bromine-water in small successive portions to pulverised codeine. The codeine dis- 
 solves, and the solution loses the colour of bromine but acquires a characteristic reddish 
 tint. On adding ammonia, the whole of the bromocodeine is precipitated as a silver- 
 white powder, containing a small quantity of unaltered codeine. It may be obtained 
 pure by repeated washing with cold water, solution in hydrochloric acid, precipitation 
 with ammonia and crystallisation from alcohol. 
 
CODEINE. 1067 
 
 Bromocodeine is nearly insoluble in cold water, rather more soluble in hot water, 
 whence it separates on cooling in small prisms with dihedral summits. It is nearly 
 insoluble also in ether, but dissolves easily in alcohol, especially at the boiling heat. 
 Better crystals are obtained from alcohol diluted with an equal volume of water. The 
 crystals are always very small, but of dazzling whiteness. They give off their 
 water (6-66 per cent.) at 100 C. The anhydrous base gives by analysis 57*44 
 per cent. C, 5 -44 H, and 21 '5 Br, the formula C 18 H 21 BrN0 3 , requiring 57'14 C, 5-29 H, 
 21-16 Br, 3-70 N, and 1271 0. 
 
 Bromocodeine melts when heated, forming a colourless liquid, which decomposes at 
 a somewhat higher temperature. It dissolves in cold sulphuric acid, the solution be- 
 coming dark coloured when heated. It is attacked by nitric acid, but much less 
 quickly than codeine. 
 
 Hydrobromate of Bromocodeine, C 18 H 2 BrN0 3 .HBr + H 2 0, forms small prisms, 
 sparingly soluble in cold water, very soluble in boiling water. It gives off its water at 
 100 C. The hydrochlorate forms radiate needles, resembling hydrochlorate of codeine. 
 The chloroplatinate, C 18 H 20 BrN0 3 .HCl.PtCl 2 (at 100 C.), is precipitated as a pale- 
 yellow powder, insoluble in water and in alcohol (platinum, by analysis, 16*98 per 
 cent. ; by calculation 16 '8 9). 
 
 Tribromo codeine, C 18 H 18 Br 3 N0 3 (Anderson, loc. tit.) When bromocodeine is 
 subjected to the continued action of bromine-water in excess, a light-yellow precipitate 
 of hydrobromate of tribromocodeine is formed, which redissolves at first, but becomes 
 permanent on further addition of bromine. On leaving the liquid to itself for 24 
 hours and then adding more bromine, a fresh precipitate is formed, and this treatment 
 must be repeated day after day as long as any further precipitate is thrown down by 
 adding bromine. The yellow precipitate is then to be washed with cold water, and dis- 
 solved in hydrochloric acid ; and the base precipitated by ammonia, purified by solu- 
 tion in alcohol, and precipitated by water. 
 
 Tribromocodeine thus prepared is an amorphous bulky powder, grey when dry, 
 insoluble in water and ether, easily soluble in alcohol. It dissolves somewhat sparingly 
 in cold, more easily in hot hydrochloric acid, a small portion however remaining un- 
 dissolved, apparently from partial decomposition. It turns brown when heated on 
 platinum-foil, and decomposes completely at its melting point, leaving a very slowly 
 combustible charcoal. 
 
 Tribromocodeine is but a weak base ; its salts are all soluble in water and amor- 
 phous. The hydrobromate, 2C 1 H 18 Br 3 N0 3 .3HBr, obtained as above, is a light-yellow 
 perfectly amorphous powder, sparingly soluble in cold, more soluble in hot water. The 
 chloroplatinate, C 18 H 18 Br 3 N0 3 .HCl.PtCl 2 , is obtained by precipitation, as a brown- 
 yellow powder, insoluble in water and in alcohol (platinum, by analysis, 13*07 per 
 cent. ; by calculation, 13-29). 
 
 CHLOBOCODEINE, 2C 18 H 20 C1N0 3 + 3H 2 0. (Anderson, loc. cit.) Dry codeine 
 treated with chlorine gas, yields a number of complex products, which have not been 
 examined. By passing chlorine into the aqueous solution of codeine, a nearly black liquid 
 is produced, from which ammonia throws down an amorphous resinous base. A more 
 definite reaction is obtained by treating codeine with chlorate of potassium and hy- 
 drochloric acid. Finely pulverised chlorate of potassium is gradually added to a 
 solution of codeine in hydrochloric acid at 65 70 C. till the liquid yields a precipi- 
 tate on addition of ammonia. Excess of ammonia is then added, which throws down 
 chlorocodeine as a silver-white or generally somewhat yellowish crystalline powder, 
 while a reddish liquid remains, containing products of a further decomposition. In 
 this process, the same precautions must be observed as in the preparation of nitro- 
 codeine (p. 1068). The chlorocodeine is freed from a small quantity of undecomposed 
 codeine by solution in hydrochloric acid, boiling with animal charcoal, precipitation 
 with ammonia, and crystallisation from a hot alcoholic solution. 
 
 Chlorocodeine resembles bromocodeine in most of its properties. It dissolves 
 sparingly in boiling water, and crystallises on cooling in small prisms, which appear 
 to be isomorphous with the crystals of bromocodeine. It is very soluble in strong 
 alcohol, especially if hot; sparingly soluble in ether. The crystals give off their 
 water (7'48 per cent.) at 100 C. The dried base gives by analysis 65-31 per cent. C, 
 6-11 H, and 10-32 Cl, the formula C I8 H 20 C1N0 3 requiring 6476 C, 5'99 H, 10-64 Cl, 
 4-19 N, and 14-42 0. 
 
 Chlorocodeine dissolves without alteration in strong sulphuric acid ; but the solution 
 is carbonised by heat. Nitric acid also dissolves it, and the solution decomposes on 
 boiling, though, much less easily than that of codeine, giving off nitrous gases and a 
 very pungent vapour. 
 
 The salts of chlorocodeine resemble those of bromocodeine. The chloropla- 
 tinate is a palo yellow precipitate, which after drying at 200 C. yields 18'29 per cent 
 
1068 CODEINE. 
 
 Pt. ; agreeing with the formula C' 8 H 20 C1N0 8 . HCl.PtCl 2 . The sulphate, 2C1 18 H 20 C1NO ! ', 
 H'-'SO 4 + 8H 2 O is deposited from a hot solution in radiate groups of short prisms, very 
 soluble in boiling water and in alcohol. 
 
 CYANOCOBEINE, C I8 H 2l N0 3 .Cy 2 (Anderson, loc. cit.} This compound, which is 
 not a substitution-product like the preceding, but rather a cyanide of codeine, is 
 produced when cyanogen gas is slowly passed into a concentrated alcoholic solution. The 
 gas is abundantly absorbed, the liquid first turning yellow, then brown ; the odour of 
 cyanogen gradually disappears, and is replaced by that of hydrocyanic acid; and crystals 
 are deposited, continually increasing in quantity, as the passage of the gas is con- 
 tinued. The mother-liquor separated from the crystals yields an additional quantity 
 if again treated with cyanogen gas. The crystals are washed with a small quantity of 
 alcohol, and dissolved in a hot mixture of ether and alcohol, into which solution 
 cyanogen is again passed to transform any codeine that may have remained unacted 
 on. Cyanocodeine then separates in thin, shining, colourless or faintly yellow, six- 
 sided laminae. It dissolves easily in boiling absolute alcohol, or in a mixture of alcohol 
 and ether, sparingly in water, more easily on addition of alcohol ; this solution how- 
 ever does not deposit anything when left at rest, and decomposes by evaporation, 
 leaving a residue of codeine. 
 
 Cyanocodeine yields by analysis 68*13 per cent. C, 6*05 H, and 11*66 N, calculation 
 requiring 68*37 per cent. C, 5*97 H, 11*68 N, and 13*97 0. 
 
 [It is perhaps a hydrocyanate of Cyanocodeine, C 18 H 20 CyN0 8 .HCy.] 
 
 With hydrochloric acid, it forms a crystallisable salt, which however quickly de- 
 composes, giving off ammonia on addition of potash ; the hydrochloric acid solution, if 
 left to stand for twenty-four hours, gives off hydrocyanic acid. With oxalic and sul- 
 phuric acids, Cyanocodeine forms sparingly soluble salts which likewise decompose 
 quickly, giving off ammonia and hydrocyanic acid. (Anderson.) 
 
 ETH YLC ODEINE, C 20 H 85 N0 3 = C 18 H 20 (C 2 H 5 )N0 3 . (H. How, Chem. Soc. Qu. J. vi. 
 125.) The hydriodate of this base is obtained by enclosing in a sealed tube pul- 
 verised codeine with a small quantity of iodide of ethyl and sufficient absolute 
 alcohol to dissolve the codeine, and heating the mixture in the water-bath for two 
 hours. On cooling, a crystalline mass is obtained, very soluble in cold water, whence 
 it is deposited, after concentration, in tufts of fine needles. Dried at 100 C., it 
 contains 52*59 per cent. C, 5*87 H, and 27'91 I, agreeing nearly with the formula 
 C 18 H 25 N0 3 ,HI, which requires 52*73 C, 5*76 H, and 27*92 I. 
 
 The solution is not precipitated either by potash or by ammonia. Treated with 
 oxide of silver, it yields a strongly alkaline liquid which absorbs carbonic acid during 
 evaporation. The residue is again attacked by iodide of ethyl, but the reaction 
 appears to be very complicated. 
 
 IODOCODEINE, C 18 H 21 NOM S . (Anderson, loc. cit.) This compound which 
 should rather be called iodide of codeine, for it is not a substitution-product is 
 prepared by dissolving equal weights of iodine and codeine in the smallest possible 
 quantities of alcohol, -mixing the solutions, and leaving the mixture at rest ; iodocodeine 
 is then deposited, after a longer or shorter time, according to the concentration of the 
 solutions, in triangular plates belonging to the triclinic system ; they have a fine ruby 
 colour by transmitted light, deep violet by reflected light, and if well illuminated, 
 exhibit a beautiful adamantine, nearly metallic lustre. They are insoluble in water 
 and in ether, but dissolve in alcohol with red-brown colour. After drying in vucuo, 
 they contain, according to the mean of Anderson's analyses, 32*07 per cent. C, 3*39 
 H, and 55*32 I, the formula requiring 31*75 C, 3*08 H, and 56 I. 
 
 Iodocodeine gives off iodine at 100 C. It is dissolved by hot sulphuric acid, and 
 slowly attacked by hot nitric acid. Boiling potash dissolves out the iodine and leaves 
 codeine. With sulphuretted hydrogen, it yields hydriodate of codeine, with deposition 
 of sulphur. With nitrate of silver, it forms an immediate precipitate, which, however, 
 contains only about | of the iodine in the compound. (Anderson, loc. cit.) 
 
 NITROCODEINE. C 8 H 2I N 2 5 = C 18 H 20 (N0 2 )N0 3 . (Anderson, loc.cit.} To pre- 
 pare this base, dilute nitric acid, of specific gravity 1*060, is heated in a flask to a tem- 
 perature short of ebullftion, finely pulverised codeine is added, and the mixture is kept 
 at a gentle heat for a few minutes, till a sample of it gives a precipitate with ammonia, 
 and the quantity of this precipitate no longer increases after several trials. The whole 
 of the solution is then saturated with ammonia and briskly agitated, whereby a thick 
 precipitate of nitrocodeine is formed. The action of the nitric acid is very rapid, the 
 transformation being complete in a few minutes, so that close watching is necessary to 
 seize the exact point at which the liquid should be saturated with ammonia. Evolu- 
 tion of red vapours is a sign that the action has gone too far, and that a portion of the 
 codeine has been converted into a peculiar red substance, not yet examined. In this 
 
COD-LIVER OIL COFFEE. 1069 
 
 case, it is best to interrupt the process before the whole of the codeine is decomposed. 
 Strong nitric acid acts on codeine with violence, producing a yellow resin. 
 
 Nitrocodeine precipitated by ammonia, as above, forms very small silvery laminae, 
 slightly tinged with yellow. It is purified from colouring matter and a little unaltered 
 codeine, by solution in hydrochloric acid, boiling with animal charcoal, reprecipitation 
 by ammonia, and recrystallisation from dilute alcohol or ether-alcohol. From alcohol 
 it crystallises in thin silky laminse of a pale tawny colour, forming, when dry, an inter- 
 laced silky mass. From ether-alcohol it separates, by evaporation, in small yellowish 
 crystals, exhibiting under the microscope the form of quadrilateral prisms with dihe- 
 dral summits. It is sparingly soluble in boiling water, and separates in small crystals 
 on cooling. It dissolves readily in boiling alcohol, sparingly in ether. It gives by 
 analysis 62'49 63'10 C, and 5-916-04 H, the formula requiring 6279 C, and 5-81 H. 
 
 Nitrocodeine when cautiously heated melts to a yellow liquid, which solidifies to a 
 highly crystalline mass. At a higher temperature, it decomposes quickly, without 
 flame, leaving a bulky charcoal. When the alcoholic solution of nitrocodeine is treated 
 with sulphide of ammonium at the heat of the water-bath, it acquires a dark colour 
 and deposits sulphur. When the action is complete, the filtered liquid yields with 
 ammonia a brown amorphous precipitate, which, after solution in hydrochloric acid, 
 boiling with animal charcoal, and reprecipitation, forms a pale yellow basic substance 
 (azocodelne), which has not been further examined. 
 
 Nitrocodeine dissolves in acids, forming salts which are neutral to test-papers, and 
 from which the base is precipitated as a crystalline powder by potash or ammonia. 
 
 The hydrochlorate is obtained by evaporation in the form of an uncrystallisable 
 resinous mass. The chloroplatinate, C l8 H'-'(N0 2 )N0 3 .HCl.PtCP + 2aq., is a yeUow 
 precipitate, insoluble in water and in alcohol. It gives off its water at 100 C., and 
 then yields by analysis 17'88 per cent. Pt (calc. 17'93). 
 
 The oxalate crystallises in short yellow prisms, very soluble in water. The sul- 
 phate, 2C 18 H'(N0 2 )N0 3 .H 2 S0 4 + 2aq. (at 100 C.), is obtained in radiate groups of 
 short pointed needles, neutral to test-paper, and very soluble in boiling water. 
 
 COB-LIVER OXXi. See OILS, ANIMAL. 
 
 CGEIiESTIW. Sr 2 S0 4 or SrO.SO 3 . Native sulphate of strontium. This mineral 
 is so named from its occasional delicate blue colour ; though 
 it is frequently found of other shades, as white, greyish and 
 yellowish- white, and red. It occurs massive, and crystal- 
 lised, sometimes also in fibrous and stellated forms. It 
 belongs to the trimetric system, being isomorphous with 
 sulphate of barium and sulphate of calcium. The primary 
 form is a rhombic prism of 104 20' and ^75 40'. An 
 ordinary combination is Poo . Poo . oo P2 (fig. 128). 
 Cleavage very distinct parallel to 00 ; less distinct 
 parallel to Poo . It has a vitreous lustre, and is trans- 
 parent, translucent, or opaque. It is very brittle. Specific gravity 3*953 (Breit- 
 haupt). Hardness 3 3-5. Before the blowpipe it fuses to a white, opaque, friable 
 enamel. Ccelestin occurs abundantly in the massive form at Montmartre, and near 
 Bristol. The crystallised variety is found in the red sandstone at Inverness, and in 
 many other localities. Splendid groups of crystals occur at Girgenti in Sicily, mixed 
 with sulphur and gypsum. Fine specimens are also met with at Bex in Switzerland, 
 Conil in Spain, Retzbanya in Hungary, in compact limestone near Lake Erie, and 
 many other localities. Crystals of coelestin are often found in which the strontium is 
 partially replaced by barium or calcium, the substitution being attended with a certain 
 alteration in the magnitude of the angles of the crystal. The blue colouring of certain 
 specimens of coelestin appears to be due to the presence of small quantities of ferroso- 
 ferric phosphate. (Jahresber. d. Chem. 1847, 1219 ; 1849, 776 ; 1850, 757 ; 1853, 842 ; 
 1855, 970; 1856, 874; 1857, 692. Dana, ii. 368.) 
 
 CCEIiOCIiINE POXiVCARPA. The tree which yields the Abeocouta bark of 
 West Africa, where it is used for colouring skins, mats, &c. ; also as a local appli- 
 cation for ulcers. According to Stenhouse, the bark contains berberine. 
 
 CCERUXiXC ACID. According to Vlaanderen and Mulder (Jahresb. d. 
 Chem. 1858, p. 262), caffeic or caffetannic acid(i. 709), which they regard as C I4 H 16 7 , 
 yields by oxidation, caffcanic acid, C"H IK 8 , and from this, by the action of air and 
 ammonia, are produced a-ccerulic acid, C 14 H lfi 9 , and &-ccerulic acid, C 14 H 14 8 , both of 
 which form blue salts, and consequently resemble viridic acid (q. v.} 
 
 CCERULIW. A name sometimes applied to the body C 8 H 15 NO, supposed to exist 
 in sulphindigotic acid, C 8 H I5 NO.S0 3 . 
 
 COFFEE. Cafe. Kaffce. Coffee beans are the seed of Caffea arabica, a tree of the 
 rubiaceous order, indigenous in southern Abyssinia. It is said to have been transplanted 
 
1070 
 
 COFFEE. 
 
 into Arabia at the beginning of the fifteenth century, and the cultivation has since 
 Leeii extended to the West Indies, Brazil, Java, Ceylon, and other warm countries. 
 The seeds are separated from the soft pods by bruising with a heavy roller, then washed 
 and dried, and lastly freed from their parchment-like coating by passing them under a 
 wooden edge-wheel, and subsequently winnowing. In this state they are sent to 
 Europe. 
 
 The most highly esteemed variety is the Mocha coffee, which is grown in the province 
 of Yemen in Arabia : it has a more agreeable taste and smell than any other kind, and 
 is distinguished by its yellow colour and the comparative smallness and roundness of 
 the bean. Next to it in European reputation, are the Martinique and Bourbon 
 coffees ; the former is larger than the Arabian and more oblong ; it is rounded at the 
 ends, of greenish colour, and almost always retains a silver-grey pellicle which comes 
 off in roasting. The Bourbon coffee approaches nearest to the Mocha, from which it 
 originally sprung. The Saint Domingo coffee, which has its two extremities pointed, is 
 much less esteemed than the preceding. 
 
 The chemical properties and composition of coffee beans have been made the subject 
 of numerous investigations. Schroeder in 1808 (Gehler's J. Chem. Phys. vi. 564), 
 showed that they contain fat, resin, mucus, extractive matter, &c., and that the aqueous 
 extract is coloured green by ferroso-ferric salts, and yields a green precipitate with 
 copper-salts on addition of an alkali. Eunge in 1820 (Matcralien zur Physiologic, 
 Lief i. p. 146) discovered caffeine: and Pfaff (Syst. d. Materia Mcdica, iii.3)found 
 in the beans, in addition to this substance, two acids, viz. caffeic and caffe.tannic 
 acids, which, however, were afterwards shown byEochleder to be identical. The 
 examination of coffee-beans was further carried out by Eobiquet and Boutron 
 (J. Pharm. xxiii. 101), who found, in addition to fat, extractive matter, and caffeine, a 
 white crystallisable substance, and an acid precipitable by neutral acetate of lead ; 
 byEochleder (Ann. Ch. Pharm. 1. 224; lix, 300; Ixiii. 193; Ixvi. 35), who found 
 legumin, and a very small quantity of citric acid (a few grains in a pound of 
 coffee); afterwards by Pay en (Ann. Ch. Phys. [3] xxvi. 108), von Bibra (Nar- 
 kotische GeniMsmittel, u. s. w. Niirnberg, 1855), and lastly by Graham, Stenhouse, 
 and Campbell (Chem. Soc. Qu. J. ix. 33). According to Payen, the caffeine exists 
 partly in the free state, partly as caffetannate of caffeine and potassium (a view consi- 
 dered as doubtful by Graham, Steuhouse, and Campbell). Payen also found sugar 
 in the unroasted beans. According to Grraham, Stenhouse, and Campbell, the unroasted 
 beans contain, partly cane-sugar, partly another kind of sugar, probably in combi- 
 nation as a glucoside, the total amount of sugar in various kinds of coffee varying 
 from 6*0 to 7'5 per cent. The caffeine amounts to 1*0 per cent, according to Payen ; 
 from 0-5 to TO according to Graham, Stenhouse, and Campbell. The amount of 
 fat appears to vary considerably. According to Eochleder, the beans contain oleiu 
 and palmitin, perhaps also laurostearin. Eobiquet and Boutron found in 8 pts. of 
 Martinique coffee, 1 pt. of fat. Payen found that Mocha coffee contains about 13 per 
 cent, of fat, which is rather greater than the proportion in Martinique coffee. The 
 fat of Mocha coffee also retains the odoriferous principle more tenaciously than that of 
 other varieties ; it is yellowish, very fluid, and separates only into two portions of 
 different melting points, whereas that of Martinique coffee has a more brownish colour, 
 is less fluid, and may be separated into at least four distinct fats, melting at about 
 o, 20, 50, and 90 C. respectively, the last being a kind of vegetable wax. Ac- 
 cording to Stenhouse, coffee beans contain about 12 per cent, of fat. According to 
 Vogel, benzene extracts from them 18 per cent, of soluble matter. 
 
 The following is the average composition of raw coffee beans, as determined by 
 Payen and von Bibra : 
 
 Payen. 
 34 
 12 
 10 to 13 
 
 Cellulose .... 
 Water .... 
 
 Fat p 
 
 Glucose, dextrin, and organic 
 
 acid 15'5 
 
 Legumin and Casein . . .10 
 Other nitrogenous substances . 3 
 Caffeine (free) . . . . 0'8 
 Caffetannate of caffeine and 
 
 potassium . . 3'5 to 5'0 
 
 Viscid essential oil (insoluble 
 
 in water) . . . . O'OOl 
 Aromatic oils, some lighter, 
 
 others heavier than water . 0-002 
 Ash 6-7 
 
 Woody fibre . 
 Water . 
 Fats 
 Sugar 
 
 Vegetable casein 
 Caffeine . 
 
 v. Bibra. 
 36 to 59 
 
 5 to 9 
 3 to 5 
 
 6 to 7 
 
 undetermined 
 0-2 to 0-8 
 
 Essential oil . . not weighable 
 
 Substances precipitable by 
 
 neutral acetate of lead . 7 to 8 
 
 Precipitable by basic ace- 
 tate of lead . . . 5 to 6 
 
 Ash . 6 to 7 
 
COFFEE. 
 
 1071 
 
 Levi (Ann. Ch. Pharm. 1. 421) found 3'2 per cent. ash. T. J. Herapath (Chem. 
 Gaz. 1848, p. 159) found 67 per cent, in the dry beans. Vogel found 3 "5 per cent, ash, 
 of which 0'80 was soluble in water. 
 
 Composition of the Ash of Coffee-beans in 100 parts.. 
 
 
 
 
 Graham, Stenhouse, and Campbell. 
 
 
 Levi. 
 
 Herapath. 
 
 Ceylon 
 cult. 
 
 Ceylon 
 wild. 
 
 Java. 
 
 Costa 
 Rica. 
 
 Jamaica. 
 
 Mocha. 
 
 Neil- 
 gherry. 
 
 Potash . 
 
 50-9 
 
 16-5 
 
 55-1 
 
 52-7 
 
 54-0 
 
 53-2 
 
 53-7 
 
 51-6 
 
 55-8 
 
 Soda .... 
 
 14-8 
 
 7-1 
 
 
 
 
 
 
 
 
 Lime .... 
 
 4-3 
 
 27-7 
 
 4-1 
 
 4-6 
 
 4-1 
 
 4-6 
 
 6-1 
 
 5-9 
 
 6-7 
 
 Magnesia . . 
 
 10-9 
 
 5-9 
 
 8-2 
 
 8-5 
 
 8-2 
 
 8-7 
 
 84 
 
 8-9 
 
 8-5 
 
 Ferric oxide . 
 
 0-6 
 
 
 0-45 
 
 0-98 
 
 0-73 
 
 0-63 
 
 0-44 
 
 044 
 
 0-61 
 
 Sulphuric acid 
 
 
 
 
 
 
 
 
 
 
 anhydrous . 
 
 trace. 
 
 1-3 
 
 3-6 
 
 4-5 
 
 3-5 
 
 3-8 
 
 3-1 
 
 5-2 
 
 3-1 
 
 Carbonic acid 
 
 
 
 
 
 
 
 
 
 
 anhydrous . 
 
 
 
 __ 
 
 17-5 
 
 16-9 
 
 18-1 
 
 16-9 
 
 16-4 
 
 17-0 
 
 14-9 
 
 Phosphoric 
 
 
 
 
 
 
 
 
 
 
 acid anhydrous 
 
 Chlorine. . . 
 
 13-6 
 1*2 
 
 40-7 
 0-4 
 
 10'3 
 M 
 
 11-6 
 0'5 
 
 11-0 
 08 
 
 10-8 
 1-0 
 
 ll'l 
 07 
 
 10M 
 0-6 
 
 10-8 
 0-6 
 
 Silica .... 
 
 3'6 
 
 0'4 
 
 
 
 
 
 
 
 
 From the analysis of the six varieties by Graham, Stenhouse, and Campbell, which 
 exhibit a remarkably close agreement, it appears that coffee-ash is especially distin- 
 guished by the absence of soda and silica. The soda found by Levi is doubtful, and 
 Herapath' s results, which differ enormously from all the rest, may be rejected as un- 
 trustworthy. 
 
 Eoasting Coffee. Coffee-beans, when heated or roasted, assume a light brown, chest- 
 nut-brown, or even black colour, according to the degree of heat applied. The air- 
 dried beans diminish in weight during roasting by 15 or 25 per cent, but increase 
 considerably in volume, the increase amounting, according to v. Bibra, to from 50 to 58 
 per cent., if they have been previously washed, or if they are strongly heated. Ac- 
 cording to Payen, 100 grms. of raw coffee-beans yield 50 grms. of roasted beans, and 
 100 vols. of the beans increase by roasting to 130 vols. To roast the beans with perfect 
 regularity, it is best to steep them in water for ten or twelve minutes, then to dry 
 them liglitly, after draining, and roast them immediately. The steeping removes im- 
 purities, and perhaps also serves to impart to the beans a uniform amount of water, so 
 that they get more regularly heated. 
 
 The vessels used for roasting coffee are generally of iron : recently silver and glass 
 vessels have also been used for the purpose. The chief point to be attended to in their 
 construction and use, is to ensure that the heat be gradual and not too strong. If the 
 beans are heated above the temperature required to brown them, they swell up strongly, 
 turn black, and ultimately become carbonised. (See lire's Dictionary of Arts, Manu- 
 factures, and Mines, i. 794.) 
 
 By heating coffee-beans in a retort with proper condensing apparatus, the following 
 volatile products are successively obtained (v. Bibra) : 
 
 1. A volatile oil, pre-existing in the raw beans, and little, or not at all altered by 
 heat. 
 
 2. Volatile oil having the odour of roasted coffee. 
 
 3. Empyreumatic oil. 
 
 4. A fatty body. 
 
 5. Acetic acid. 
 
 6. A small quantity of caffeine, together with an aromatic body, probably assamar 
 (i. 428). 
 
 7. Humoi'd substances, and one or more compounds which easily reduce gold and 
 silver-salts. 
 
 The statement of Kochleder that pyrocatechin is formed in the distillation (from 
 the caffetannic acid), is not confirmed by the observations of Graham, Stenhouse, and 
 Campbell. 
 
 The composition of roasted coffee has been investigated by Payen, by v. Bibra, and 
 by Graham, Stenhouse, and Campbell. Payen exhausted 100 grms. of ground coffee 
 with a litre of boiling water; heated the filtrate in a distillatory apparatus for two 
 hours, by which time it had quite lost its odour ; and collected the distillate in four 
 connected receivers, the first of which gradually became heated to about 90 C., while 
 the second was kept between 25 and 30, and the third and fourth were cooled to 0, 
 or a little below, the vapours which escaped from the fourth being passed through 
 strong sulphuric acid, or through a tube filled with red-hot oxide of copper. 
 
1072 COFFEE. 
 
 In the first receiver, a yellowish water collected, and a few drops of oil, amounting 
 to about i of the infusion, floated on the surface, quite destitute of fragrance. The 
 liquid condensed in the second receiver amounted to about ~ of the volume of the in- 
 fusion : a few drops of an odourless fixed oil floated on the top of the watery liquid, 
 which possessed the fragrant odour of coffee in so high a degree that a few drops of it 
 sufficed to impart the odour to a cup of milk. The water of this second receiver con- 
 tained the principal part of the coffee-aroma, concentrated about IOC times. On agi- 
 tating the water with about | of its volume of ether, repeating this treatment several 
 times, and then evaporating the ether, there remained a yellowish oil (about O'l grm. 
 from 10 grms.), the very strong odour of which resembled that of the aroma common 
 to the several varieties of 'coffee. Another oil, somewhat more volatile, and of more 
 delicate aromatic odour, remained, together with a little ether, in the water: this oil 
 appears to be contained especially in the finer kinds of coffee, as that of Mocha. 
 
 To obtain the whole of the oils from the infusion of coffee, lumps of chloride of 
 calcium are introduced into the first two receivers during the distillation ; the third 
 receiver is connected with a chloride-of-calcium-tube and cooled to + 20 C. A solu- 
 tion of chloride of calcium is then obtained, containing the whole of the volatile coffee- 
 oil, which may be extracted from it by agitation with ether. Payen obtained from 
 10,000 pts. of coffee only 2 pts. of this oil, but possessing so strong an odour that a 
 single drop sufficed to fill a whole room with the characteristic odour of coffee. 
 
 If the third receiver be cooled to 2 or 3 C. during the distillation, a few drops 
 of liquid collect in it having the odour of coffee, but likewise the less agreeable odour of 
 empyreumatic hydrocarbons, which are present in greater quantity in proportion as the 
 coffee has been more strongly roasted. The odour of these bodies is perceptible also 
 in the fourth receiver and in the vapours which escape therefrom, these vapours like- 
 wise imparting a brown colour to oil of vitriol. 
 
 According to Zenneck, the aroma of coffee is obtained in larger quantity by adding 
 sulphuric acid to the liquid in the retort. 
 
 Von Bibra, by exhausting roasted coffee-beans with ether, obtained from Mocha coffee 
 8*8 to 9-3 per cent, fatty matter; from Java coffee 8'9 to 9-2 per cent. He supposes 
 that this fat is for the most part produced during the roasting, inasmuch as the raw 
 beans yielded only from 4 to 5 per cent, of fat ; and, if the beans thus exhausted were 
 subsequently roasted, they yielded an additional 4 to 6 per cent, fat on being again 
 treated with ether. It is possible, however, that the fat in the raw bean is enclosed 
 in cells, and does not become accessible to the ether till the envelopes are burst by the 
 heat. 
 
 The fat extracted by ether has the consistence of cacao-butter (i. 699), and exhales 
 the peculiar aroma of coffee, which appears to be produced from the volatile oil of the 
 raw beans by roasting ; by boiling the fat with water this aroma is driven off. The 
 fat is a mixture of several substances, some of which are likewise soluble in alcohol. 
 It appears to contain olein and palmitin, together with a resin and a hydrocarbon ; 
 perhaps also other bodies. The ethereal extract likewise contains the whole of the 
 caffeine, and a body which colours iron-salts greenish, precipitates lead-salts, and re- 
 duces gold and silver-salts. 
 
 When ground coffee which has been exhausted with ether, is twice heated with 
 boiling water, after drying, a dark brown, strongly acid liquid is obtained, having a 
 very bitter taste, but without the peculiar agreeable flavour of coffee. The aqueous 
 extract likewise contains sugar, humoi'd substances, assamar, and tannic acid, nearly 
 identical with caffetannic acid ; also a substance which reduces gold- and silver-salts, 
 a small quantity of empyreumatic oil, salts, and indifferent substances insoluble in 
 alcohol. The brown bitter products in roasted coffee appear to be produced chiefly 
 from the sugar, inasmuch as that substance diminishes greatly in quantity, or disap- 
 pears altogether, in the roasting process. Graham, Stenhouse and Campbell found 
 that, whilst the raw beans contained 57 to 7*8 per cent, sugar, the roasted beans never 
 contained more than 1-1 per cent., and in many instances none at all. 
 
 The residue, after extraction with ether and water, yielded by boiling with water 
 containing carbonate of sodium, a solution coloured deep brown by humoi'd substances. 
 
 Decoction of coffee does not contain albumin or legumin. 
 
 Graham, Stenhouse, and Campbell found in roasted coffee, a brown volatile oil (the 
 caffeone of Boutron and Fremy). heavier than water, easily soluble in ether, sparingly 
 in boiling water, but communicating to the water a strong aromatic odour. They 
 also found from 2 '5 to 3'0 per cent, nitrogen and sometimes a little sugar. 
 
 Von Bibra finds that when ground coffee is treated with boiling water in a French 
 coffee-machine, in which the boiling water is forced by the pressure of its own vapour 
 from the lower vessel into the upper, which contains the coffee, from 10 to 12 pts. 
 out of 100 of the coffee pass info the solution : by complete exhaustion, a larger 
 proportion would of course be dissolved. The proportion of soluble matter is increased, 
 
COFFEE. 1073 
 
 up to a certain point, by strong roasting. According to Cadet, coffee roasted to a red- 
 brown colour yields 12 '3 per cent.; chestnut-brown coffee 18 '5 per cent.; and dark 
 brown 237 per cent, of soluble constituents. Payen obtained 37 per cent., and the 
 residue, after thorough exhaustion with water, yielded only 1 *2 per cent, ash, i of which 
 consisted of soluble salts. Lehmann found in roasted Java coffee, 21*5 per cent, 
 soluble matter. Vogel found 39 per cent, (in the raw beans only 25 per cent.). Soft 
 water dissolves out more than hard water ; water containing carbonate of soda most 
 of all. 
 
 The aqueous extract of coffee yields 166 per cent, ash, containing 51'5 percent. 
 K 2 0, 3-6 Ca 2 0, 8-6 Mg 2 0, 0-2 Fe 4 3 , lO'O P 2 5 , 40'0 SO 3 , 20'5 CO 8 , 2-0 KC1, 07 SiO 2 , 
 with 0'5 sand and charcoal. 
 
 Physiological action. Coffee acts physiologically in two ways : first, by stimulating 
 the action of the nervous and vascular systems, thereby producing a feeling of cheerful- 
 ness and mental activity ; secondly, by retarding the transformation of tissue, and thus, 
 to a certain extent, supplying the place of other nutriment. Experience has in fact 
 shown that labourers who habitually take coffee as a beverage, require less nitrogenous 
 food to keep up their strength than those who do not take coffee. The stimulating and 
 invigorating action of coffee appears to depend both upon the empyreumatic oil and 
 the caffeine ; the retardation of tissue-transformation, chiefly on the empyreumatic oil, 
 the caffeine acting in this manner only when it is present in considerable quantity. 
 The unpleasant symptoms which sometimes attend an excessive use of coffee, such as 
 headache, trembling, and a peculiar delmous sensation, are mainly due to the caffeine 
 ( J. Lehmann, Ann. Ch. Pharin. Ixxxvii. 207). The assamar and tannic acid in roasted 
 coffee doubtless also contribute in some way to its physiological action. 
 
 Tea resembles coffee in containing theine (identical with caffeine) and tannic acid ; 
 and, accordingly, its action resembles that of coffee to a certain extent ; it differs from 
 coffee, however in not containing the peculiar empyreumatic oils just mentioned, and 
 in being richer in theine and tannin. 
 
 Adulteration of Coffee. (Graham, Stenhouse, and Campbell, loc. cit.} 
 Varioiis substances, more or less resembling coffee, are used, either as substitutes for, 
 or additions to it. A great variety of seeds were tried in France during the con- 
 tinuance of the continental blockade, including in addition to maize, barley, oats, 
 and the other cereals the seeds of the yellow flag (Iris pseudo-acorus\ the grey or 
 chick pea (Cicer arietinuni), the milk vetch or Andalusian astragalus (Astragalus 
 boeticus), the Hibiscus esculentus, the holly, Spanish broom, acorns, chestnuts, the small 
 lupine (Lupinus augustifolia), peas, haricots, horse-beans, sunflower, pips of the goose- 
 berry and grape eglantine (Rosa villosa), and the capsules of box (Buxus sempervirens). 
 Of these the yellow flag, a common marsh-plant in England, appears to offer the 
 greatest similarity to coffee ; but it is doubtful whether the resemblance extends beyond 
 the aroma of the seed when roasted. Indeed no seed appears to be known which, when 
 roasted and pulverised, forms a true and efficient substitute for coffee, either in the phy- 
 siological properties or in the chemical composition of the soluble extract. The poorer 
 sorts of coffee-beans are sometimes tinted by dusting them with coloured powders, such 
 as Prussian blue, powder of lime-tree charcoal, green earth, &c., mixed with a little gra- 
 phite, to give them the silvery appearance of the finer sorts. 
 
 The use of certain roots roasted and pulverised, to mix with ground coffee, is, how- 
 ever, much more common. The roots most used for this purpose are those of chicory 
 (Cichorium intybus), carrot, beet, rush-nut (Cyperus esculentus}, earth-nut (Arachis 
 hypogcea), scratch- weed ( Galium aparine), fern (Polypodium filix mas), and butcher' s- 
 broom (Ruscus aculeatus}. 
 
 These roots are prepared by cutting them into thin slices, drying them on a stove, 
 and then passing them through a coffee-roaster, generally with addition of about 2 per 
 cent, of butter, and sometimes of a red powder, to give them the colour of coffee. In 
 this country and in France, the root most used as an addition to coffee is chicory, 
 the annual consumption of which in France amounts to 6,000,000 kilogrammes. In 
 Germany, beet and carrot are extensively used for the same purpose. Not one of these 
 roots contains either caffeine or the peculiar aromatic oils of roasted coffee, and hence 
 they can never serve as efficient substitutes for coffee ; but they are valued as an addition 
 to it, because they contain a large quantity of sugar chicory as much as 30 per cent. 
 and consequently, when roasted, acquire the peculiar bitter taste and somewhat of 
 the aroma of caramel or burnt sugar, which is well known to be one of the strongest and 
 most general of our gustatory preferences, being that which gives the peculiar flavour 
 to the several varieties of brown beer or porter (i. 529). 
 
 The examination of a sample of ground coffee for the detection and estimation of 
 these admixtures, is a matter of some difficulty. As none of the roots contain caf- 
 feine, the quantitative determination of that base in the sample may give an approxi- 
 
 VOL. I. 3 Z 
 
1074 COFFEE. 
 
 mation to its degree of piu-ity. For this purpose, the coffee may be exhausted by 
 repeated boiling with hot water ; the solution concentrated a little by evaporation ; 
 the caffetannic acid, and certain other substances, precipitated first by neutral and then 
 by basic acetate of lead ; the excess of lead removed from the filtrate by sulphuretted 
 hydrogen ; the liquid then evaporated to dryness ; the dry matter exhausted with spirit 
 of specific gravity 0'840 ; and the alcoholic solution concentrated to a nearly syrupy 
 state, and left to stand for ten days. The crystals of caffeine, which then separate, 
 are collected on a small filter, compressed powerfully to remove the mother-liquor, then 
 redissolved in a small quantity of water, and the solution is evaporated and crystallised 
 anew. It yields almost pure caffeine, the quantity of which in the sample is thus 
 determined. Samples of pure coffee of several varieties yielded, by this treatment, from 
 0'80 to 1-01 per cent, caffeine; if then the amount obtained from a given sample be 
 less than 0-80, the admixture of some other substance may be inferred. (Grraham, 
 Stenhouse, and Campbell.) 
 
 If it be desired merely to determine whether a given sample of ground vegetable 
 substance contains coffee or not, the search for caffeine may be made by a simpler 
 process, namely, by evaporating the aqueous infusion to dryness after addition of lune, 
 treating the dry mass with ether, leaving the solution to crystallise by evaporation, and 
 testing the crystals with nitric acid and ammonia, whereby, if caffeine be present, the 
 purple colour of murexid is produced (i. 708). 
 
 The formation of quinone by the oxidation of caffetannic acid (i. 709), may also 
 be used as a means of recognising the presence of coffee in a mixture. For this purpose 
 the infusion of the powder is evaporated to syrup, and 1 pt. of the residue is distilled 
 with 4 pts. peroxide of manganese, and 1 pt. oil of vitriol diluted with 1 vol. water ; 
 quinone is then given off, part subliming in crystals, while the rest passes over with 
 the watery distillate. (Grraham, Stenhouse, and Campbell.) 
 
 The adulterations of coffee are most easily detected by their physical characters, 
 by the proportion of sugar contained in the sample, and by the composition of the ash. 
 
 1. Action of Water. When hot water is applied to the powder of chicory and other 
 roots, it softens immediately, from the facility with which the water is imbibed ; 
 whereas the grains of coffee remain hard and gritty. Boasted grain, such as wheat 
 and barley, gives with hot water a thick mucilaginous infusion, while the infusion of 
 coffee is remarkably thin and limpid. The grain-infusion generally contains starch, 
 and gives a blue coloration with iodine, whereas the infusions of both coffee and chicory 
 appear to be quite destitute of starch. 
 
 2. Colouring Power. Chicory and the allied roots impart to water a much deeper 
 colour than coffee, the coloration being also much more rapidly produced. By in- 
 fusing equal quantities of the several substances with boiling water, and observing the 
 colour of the filtered infusions in glass tubes of equal diameter, it was found: if the 
 colouring power of caramel be represented by 1000, that of chicory is 450, of maize 
 350, of dandelion-root 300'3, of red beet 300-3, of bread-raspings 27472, of acorns 
 200, of highly-roasted coffee 173-31, of medium-roasted coffee 143-88, of peas 73-1S, 
 and of brown malt 25. Hence it appears that chicory has more than three times the 
 colouring power of highly-roasted coffee ; maize double that of coffee ; whereas peas and 
 beans have only about half the colouring power of coffee. 
 
 In infusions prepared with cold water, chicory exhibits four times the colouring power 
 of coffee. If a few grains of roasted chicory or any other sweet root be dropped into 
 a glass of cold water, without being stirred, a yellowish-brown colour diffuses rapidly 
 through the liquid, whereas pure coffee gives no sensible colour to the water under 
 similar circumstances. 
 
 3. Specific Gravity of the Infusions. Coffee is sharply distinguished from the two 
 most important classes of adulterating substances, the roots and cereals, by the com- 
 paratively low specific gravity of its infusion. The comparison may be made by dis- 
 solving 1 pt. of the substance in 10 pts. of cold water, raising the temperature to the 
 boiling point, keeping it there for about half a minute, and then filtering. The legu- 
 minous seeds give infusions of low specific gravity: peas 1007'3, beans 1008-4. The 
 specific gravity of coffee infusions varies from 1008*0, for Mocha, to 1009-5, that of 
 Costa Rica coffee ; that of chicory infusion is much higher, ranging in different samples 
 from 1019-1 to 1023-2. Infusions of cereals stand equally high, or higher, in the 
 scale of gravity, rye-meal giving 1021-6, and maize 1021-5. 
 
 4. Action of Ether. The following substances, agitated with ten times their weight 
 of ether, give different proportions of matter soluble in that liquid, viz. : 
 
 Eoasted beans 1-81 per cent, of oil and resin, 
 
 maize 5-15 
 
 chicory (Yorkshire) . . 6*83 ,, 
 
 coffee (Mocha) . . . 15-93 
 
COFFEE LEAVES COFFEINE. 1075 
 
 the last including probably 1 per cent, of caffeine. Hence it appears that coffee yields 
 to ether much more soluble matter than beans, maize, or chicory, which represent the 
 three classes of leguminous seeds, cereals, and sweet roots. The fat obtained from 
 chicory was doubtless that which is added in the roasting process, to prevent burning. 
 The experiment with ether is easily made, and may sometimes prove valuable. 
 
 5. Quantity of fermentable Sugar, The quantity of fermentable sugar in sweet 
 roots, both before and after torrefaction, is much greater than in coffee. By subjecting 
 the different substances to fermentation with yeast, and determining the amount of 
 alcohol in the distillate (see SUGAR), the sugar in raw coffee is found to vary from 6 '20 
 to 7'52 per cent.; that of roasted coffee from 0-0 to 1-14. The proportion in chicory 
 and other sweet roots is given in the following table : 
 
 Sugar per cent. 
 
 Raw. Roasted. 
 
 Foreign chicory 2376 11-98 
 
 Guernsey 30'49 15'96 
 
 English 35-23 17'98 
 
 (Yorkshire) .... 32-06 9-86 
 
 Mangold-wnrzel 23-68 9-96 
 
 Carrots (ordinary) 31-98 11-53 
 
 Turnips 30-48 9-65 
 
 Beetroot (red) 24-06 17'24 
 
 Dandelion root 21'96 9'08 
 
 Parsnips 2170 6'98 
 
 Bonka (a coffee substitute) .... 5*82 
 
 These numbers are sufficient to show that the fermentation-test affords an easy 
 method of distinguishing these roots from coffee. The leguminous seeds, cereals, and 
 other seeds are not so easily distinguished by this method, the proportion of sugar in 
 the roasted material varying only from 074 in lupine seed to 2*70 in acorns. 
 
 6. Composition of the Ask. Coffee is remarkably distinguished from the roots and 
 cereals by the small quantity of silica in its ash, which never exceeds 0'5 per cent. ; 
 and even this small quantity, which is not always present, probably arises from acci- 
 dental adhesion of sand to the beans. Chicory-ash, on the other hand, contains (after 
 deducting sand) from 3'81 to 10-52 per cent, silica (i. 962), and roasted dandelion-root 
 11-26 per cent. The proportion of silica maybe determined, without making a formal 
 analysis of the ash, by simply digesting it in strong hydrochloric acid and weighing 
 the residue. In lupines, acorns, maize, and parsnips, the proportion of silica is not 
 large enough to afford a good distinction from coffee; but lupine-ash contains 1775 
 per cent, of soda, which, according to Graham, Stenhouse, and Campbell, is not found 
 in coffee-ash; the ashes of lupines and of acorns likewise contain twice as much 
 chlorine as coffee-ash, and in the ash of maize the proportion of phosphoric acid is 
 very high, viz. 44'5 per cent., whereas in coffee-ash it is only about ten per cent. 
 Beetroot ash is distinguished from coffee-ash by its very large amount of chlorine, 
 which varies from about 8 to 29 per cent. 
 
 7. Proportion of Nitrogen. The nitrogen in foreign raw chicory amounts to 1*51 per 
 cent, in the roasted root to 1'42 per cent. English chicory gave, in the raw state T86, 
 in the roasted state 174 per cent, nitrogen. In roasted coffee the proportion of ni- 
 trogen is rather greater, viz. about 275 per cent. ; but the difference is not great 
 enough to afford a good mode of distinction. It may, however, be admitted that less 
 than 2 per cent, of nitrogen in coffee is a strong presumption of adulteration with 
 chicory or some other root. 
 
 On the whole, we may conclude that the best indication-tests of the presence of 
 foreign substances in ground coffee are afforded by the colouring power, the specific 
 gravity of the infusion, the fermentation-test, and the composition of the ash. 
 
 COFFEE LEAVES. The leaves of the coffee tree have been examined by 
 Stenhouse (Phil. Mag. [4] vii. 21), who received a sample of them, dried at rather 
 too high a temperature, from Sumatra. They were found to contain 1-2 per cent, caf- 
 feine, and altogether 2-1 per cent, nitrogen ; as some of the caffeine may have been 
 decomposed in the drying of the leaves, the real proportion may perhaps amount to 
 1-5 per cent. They also appear to contain a larger proportion of caffetannic acid than 
 the beans ; the proportion of matter extracted by water was 38'8 per cent. An infu- 
 sion of the leaves in boiling water has a deep brown colour, and in taste and odour 
 resembles a mixture of tea and coffee. The leaves might therefore, perhaps, be used 
 as a substitute for tea-leaves or coffee-beans. Their use for this purpose was first 
 suggested by Van den Corput in Brussels. (Ann. Ch. Pharm, Ixxxix. 244.) 
 
 COFFEXNE. Syn. with CAFFEINE (i. 707). 
 
 3z2 
 
1076 COGNAC COHESION 
 
 COGXT AC. The finest kind of French brandy distilled from wine ; it takes its 
 name from the town of Cognac, in the Depart ement de la Charente. (See BRANDY. 
 i. 652.) 
 
 COKOB ATION. The continuous redistillation of the same liquid from the same 
 materials. 
 
 COHESION and ADHESION*. Cohesion is the force by which particles of one 
 aud the same body, or homogenous particles in general, are held together. Adhesion 
 that which holds together the particles of two dissimilar bodies when brought into 
 close contact. 
 
 These forces appear to act only at distances inappreciable to our senses. When a solid 
 body, as a piece of wood or stone, is broken, the pieces cannot be made to cohere again 
 by merely pressing them together, because the surfaces, being uneven, can only come 
 into contact at a few points, and the cohesive force is imperceptible ; but if the bodies 
 touch each other by large flat surfaces, as when two well polished plates of glass or 
 metal are pressed together, they cohere with great force. 
 
 The adhesion between the particles of dissimilar bodies is determined by precisely 
 similar conditions. Plates of lead and tin, or of copper and silver, may be almost in- 
 separably united by strong pressure between rollers. Adhesion takes place with pecu- 
 liar facility when one or both of the bodies is in the liquid state, because the particles, 
 being free to move, can easily adapt themselves to each other. All liquids, like oil and 
 water, which do not mix, adhere with more or less force by their surfaces, and adhesion 
 shows itself in most cases when a liquid comes in contact with a solid body, the liquid 
 being then said to wet the solid. A glass plate suspended from the arm of a balance 
 and made to touch the surface of water requires considerable force to separate it. If 
 the liquid which adheres to the surface of the solid afterwards solidifies, the adhesion 
 becomes still stronger : this is the principle of cementing. When two glass plates are 
 joined together with sealing wax, the adhesion is sometimes so strong that in attempt- 
 ing to part them, particles of the glass separate from each other rather than from the 
 wax. 
 
 Notwithstanding the great difference which appears to exist between these mole- 
 cular forces, and that of gravitation, the former acting only at insensible, while the 
 latter acts at all distances, it is not difficult to show that both kinds of attraction may 
 be merely different modifications of the same power. Let it be assumed that all ulti- 
 mate atoms attract one another with forces varying directly as their masses and in- 
 versely as the squares of the distances between them, and that the aggregates of atoms 
 constituting the physical molecules are not spherical, at least not in all cases. The 
 law of molecular attraction will then depend in great part on the forms and dimen- 
 sions of these molecules. The attraction between spheres composed of particles which 
 attract one another according to the law of the inverse squares, is the same as if the 
 whole matter of each sphere were concentrated in its centre, that is to say, the 
 spheres attract one another inversely as the square of the distance between their 
 centres. But in bodies of any other shape, the attraction may be regarded as consist- 
 ing of two parts, one following the law of the inverse squares, just as if the bodies were 
 spherical, the other dependent on the shape of the bodies, and varying inversely as the 
 cube of the distance between their centres of gravity. Such is the case with the attrac- 
 tion of the earth and moon. The equatorial protuberance of the earth produces certain 
 perturbations in the relative movement of the two bodies, which vary in magnitude, 
 according to the law last stated, and would become much more perceptible if the earth 
 and moon were nearer to each other, but would vanish if the distance between them were 
 much greater than it is : for example, if the distance were diminished to ^ of its present 
 amount, the principal part of the attractive force, which determines the elliptical mo- 
 tion, would be increased 100 times, but the disturbing force depending on the figure 
 would be increased 1000 times. If then the law of attraction between the molecules of 
 bodies be affected in like manner by their figures, it will follow that at the extremely 
 small distances existing between the particles of a solid body or of two bodies pressed 
 closely together, the molecular force, which determines the phenomena of cohesion and 
 adhesion, may become almost immeasurably greater than when they are separated by 
 any appreciable distance : for the molecules are so minute that the smallest distance 
 appreciable to our senses may be regarded as infinitely great compared with their di- 
 mensions, so that it is only at insensible distances that the influence of their form 
 makes itself felt. 
 
 The force of cohesion varies with the temperature and the nature of the body. In 
 gases, in which the dimensions of the actual material particles must be supposed to be 
 infinitely small as compared with the intervals between them, the cohesive force is 
 little, if at all perceptible ; in fact, the particles of gases have a constant tendency to fly 
 asunder. (See GASES and HEAT.) 
 
COHESION. 
 
 1077 
 
 In liquids, the distance between the particles is still sufficiently great, compared 
 with their size, to give great freedom of motion, but not sufficient to render the 
 molecular attraction depending on the form of the particles imperceptible ; hence 
 liquids, though their particles yield with ease to any external force, nevertheless ex- 
 hibit, when left to themselves, a tendency to assume the spherical form, that being 
 the arrangement in which a given number of particles occupy the smallest space ; 
 since, however, the liquid mass is subject to the influence of other forces, as gravita- 
 tion and adhesion, the spherical form of a drop is never perfect ; this may be seen in 
 the form which drops of mercury assume on glass, or water on glass smeared with fat 
 or lycopodium. As the temperature rises, the cohesive force becomes less, in conse- 
 quence of the greater separation of the particles ; consequently a heated liquid gene- 
 rally forms smaller drops than a cold one. Different liquids exhibit different degrees 
 of cohesion, the cohesive power being very nearly proportional to the density. 
 
 In solids, the cohesive power shows itself in the highest degree, the particles 
 not being able to move freely over one another, so that an external force, if it 
 does not produce disruption, gives rise to an equal and parallel motion throughout the 
 
 The force of cohesion in a solid is measured by the resistance which the body offers 
 to any mechanical force tending to separate the particles. The resistance offered to 
 a force tending to pull the particles asunder is called the absolute cohesion or 
 tenacity; the lateral resistance to fracture is the relative tenacity; and the resist- 
 ance which the body opposes to a crushing force is sometimes called the retroactive 
 tenacity (ruckwirkende Festigkeif). These three modifications of the cohesive 
 strength have all been made the subject of direct experiment in numerous bodies ; 
 they are connected with each other by relations which are capable of exact 
 mathematical analysis, but the investigation of which is foreign to the character of 
 this work. 
 
 Absolute tenacity Muschenbroeck made numerous experiments on the absolute 
 tenacity of bodies; his results are given in the following table, which shows the 
 weights required to break rods or wires of various materials when suspended from 
 them : 
 
 Absolute Tenacities of Solids 
 
 Horizontal section Horizontal section 
 
 = | square line. = sq. centimetre. 
 
 Elm-wood 87 pounds 918 kilogr. 
 
 Pine (Pinus silvestris) . . 97 1021 
 
 Fir (Pinus abies) . . . 6788 600929 
 
 Oak 110140 11501466 
 
 Beech 136148 13491586 
 
 Ebony ...... 89 934 
 
 Copper wire . - . . . . 266 2782 
 
 Brass 340 3550 
 
 Gold 442 4645 
 
 Lead 26 272 
 
 Tin 43 457 
 
 Silver 326 3411 
 
 Iron 398 4182 
 
 Glass (white) . . . 1422 142233 
 
 Hempen cord . . . 3460 350360 
 
 The great variation in the strength of hempen cord arises from the unequal quality 
 of the fibre. Thin cords are comparatively stronger than thick ones, because they are 
 made of better hemp. 
 
 The number for gold in the above table is doubtless too high. According to Count 
 Sickingen, the tenacities of different metals are to one another in the following propor- 
 tions : 
 
 Gold . 
 Silver . 
 Platinum 
 
 150955 
 190771 
 262361 
 
 Copper 
 
 Soft iron (Swedish) 
 
 Hard iron . 
 
 304696 
 362927 
 559880 
 
 The following table exhibits the absolute tenacities of different metals at the tem- 
 peratures of 0, 100, and 200 C., as determined by Baudrimont (Ann. Ch. Phys. 
 [3] xxx. 304.) The upper number opposite each metal gives the highest tenacity ob- 
 served ; the lower number the mean of each set of experiments : 
 
1078 
 
 COHESION. 
 
 Metals. 
 
 Tenacity in grammes for a transverse section of 1 mm. at 
 
 
 
 100 
 
 200 
 
 Gold . 
 Platinum 
 Copper . 
 Silver . 
 Palladium 
 Iron 
 
 19051 
 18400 
 
 23026 
 22625 
 
 25338 
 25100 
 
 28620 
 28324 
 
 36983 
 36481 
 
 (209813 
 j 205405 
 
 15766 
 15224 
 
 20421 
 19284 
 
 22050 
 21873 
 
 24526 
 23266 
 
 32871 
 32484 
 
 201039 
 191725 
 
 13094' 
 12878 
 
 18118 
 
 17277 
 
 19839 
 18215 
 
 18705 
 18577 
 
 29212 
 27077 
 
 213305 
 210270 
 
 These numbers show that the tenacity diminishes for the most part as the tempera- 
 ture rises ; iron, however, exhibits an exception, being more tenacious at 200 than 
 at 100 C. 
 
 Resistance to crushing. The following table is the result of experiments by George 
 Rennie, jun., published in the first part of the Philosophical Transactions for 1818. 
 
 Mr. Kennie found a cubic inch of the following bodies crushed by the following 
 weights : 
 
 Crushing weight 
 in Ihs. av. 
 
 Elm 1284 
 
 American pine 1606 
 
 White deal 1928 
 
 English oak 3860 
 
 A prism of Portland stone, 2 inches long 805 
 
 Ditto statuary marble . 3216 
 
 Craigleith stone 8688 
 
 Cubes of li inch. 
 
 Sp. gr. 
 
 Chalk 1127 
 
 Brick of a pale red colour 2-085 1265 
 
 Roe-stone, Gloucestershire -r- 1449 
 
 Red brick, mean of two trials ..... 2*168 1817 
 
 Yellow-face baked Hammersmith paviors, three times . 2254 
 
 Burnt ditto, mean of two trials ..... 3243 
 
 Stourbridge, or fire brick 3864 
 
 Derby grit, a red friable sandstone .... 2-316 7070 
 
 Derby grit from another quarry 2*428 9776 
 
 Killala white freestone, not stratified . . . .2-423 10264 
 
 Portland 2*428 10284 
 
 Craighleith white freestone 2'452 12346 
 
 Yorkshire paving, with the strata .... 2-507 12856 
 
 Ditto, against the strata 2'507 12856 
 
 White statuary marble, not veined .... 1760 23632 
 
 Bramley-Fall sandstone, near Leeds, with strata . . 2-506 13632 
 
 Ditto, against strata 2'506 13632 
 
 Cornish granite 2'662 14302 
 
 Dundee sandstone, or breccia, two kinds . . . 2*650 14918 
 
 A two inch cube of Portland 2-423 14918 
 
 Craighleith, with strata 2*452 15560 
 
 Devonshire red marble, variegated . . . 16712 
 
 Compact limestone 2-584 17354 
 
 Peterhead granite, hard close-grained . . . , 18636 
 
 Black compact limestone, Limerick .... 2-598 19924 
 
 Purbeck 2'599 20610 
 
 Black Brabant marble 2-697 20742 
 
COHESION. 1079 
 
 Cubes of 1| inch (continued). 
 
 Crushing weight 
 Sp. gr. in IDS. av. 
 
 Very hard freestone 2'528 21254 
 
 White Italian veined marble 2725 21783 
 
 Aberdeen granite, blue kind 2-625 24556 
 
 Cubes of different metals of | inch were crushed by the following weights : 
 
 Ibs. av. 
 
 Cast iron 9773 
 
 Cast copper 7318 
 
 Fine yellow brass . 10304 
 
 Wrought-copper 6440 
 
 Cast tin 966 
 
 Cast lead 483 
 
 Bars of different metals, 6 inches long, and \ of an inch square, were suspended by 
 nippers, and broken by the following weights : 
 
 Ibs. av. 
 
 Cast iron, horizontal 1166 
 
 Ditto, vertical 1218 
 
 Cast steel, previously tilted 8391 
 
 Blistered steel, reduced by the hammer 8322 
 
 Shear steel, ditto 7977 
 
 Swedish iron, ditto 4504 
 
 English iron, ditto 3492 
 
 Hard gun-metal, mean of two trials 2273 
 
 Wrought copper, reduced by hammer 2112 
 
 Cast copper 1192 
 
 Fine yellow brass 1123 
 
 Cast tin . 296 
 
 Cast lead 114 
 
 On the tenacity and other mechanical properties of cast iron, a large number of ex- 
 periments were made by Stephenson, Fairbairn, and Hodgkinson, in connection with 
 the construction of tubular bridges ( The Britannia and Conway Tubular Bridges, by 
 Clarke, London, 1850; Ann. Min. [4] xx. 427). The experiments on the resistance 
 to direct tension, gave for the absolute tenacity of cast-iron a mean value of 10 to 11 
 kilogrammes for a square millimetre. The retroactive tenacity was found to be on 
 the average 57 times greater than the absolute tenacity. 
 
 The tenacity of glass has been examined by Fairbairn and Tate (Proc. Roy. Soc. 
 x. 6). The absolute tenacity determined by direct stretching was found to be for : 
 
 Tenacity per sq. in. in Ibs. 
 
 Flint glass (best; specific gravity 3-0782) 2413 
 
 Green glass (specific gravity 2'5284) 2896 
 
 Crown glass (extra white; specific gravity 2-4504) . . . 2346 
 
 But from experiments on the resistance of glass globes to internal pressures, much 
 
 higher values were found for the absolute tenacities, viz. for : 
 
 Tenacity in Ibs. 
 
 Flint glass 4200 
 
 Green glass 4800 
 
 Crown glass 6000 
 
 These results are regarded by the-authorsas more trustworthy than the former, be- 
 cause the globes were better annealed than the rods used in the first experiments. 
 
 Experiments on the resistance of glass to crushing were made upon small cylinders 
 and cubes crushed between parallel steel surfaces by means of a lever. The cylinders 
 were cut from rods drawn to the required diameter while hot, and then annealed. 
 The cubes were cut from much larger portions, and were probably less thoroughly an- 
 nealed. For this reason, the experiments on cylinders, which gave nearly twice the 
 resistance afforded by the cubes, are regarded as the more trustworthy. The follow- 
 ing table gives the mean results : 
 
1080 COLCHICEINE COLCHICINE. 
 
 Resistance of Glass to Crushing. 
 
 
 Mean crushing weight in Ibs. per sq. inch. 
 
 For cylinders. 
 
 For cubes. 
 
 27582 
 31876 
 31003 
 
 13130 
 20206 
 21762 
 
 
 Crown glass 
 
 COLCHICEHSTE, C 35 H 42 N 2 (Oberlin, Ann. Ch. Phys. [3] 1. 108). An alka- 
 loid prepared from colchicine by acidulating the aqueous solution of that body with 
 sulphuric or hydrochloric acid, concentrating the liquid to dry ness over the water- 
 bath, then adding water, and crystallising from alcohol the yellow mass which 
 separates. At the same time there is produced, by the action of the acid on the col- 
 chicine (perhaps impure), a resin which dissolves in alcohol and in ether, and with 
 deep red colour in ammonia or nitric acid. According to Oberlin, colchiceine exists 
 ready formed in the seeds of Colchicum autumnale. 
 
 Colchiceine crystallises in colourless nacreous laminae or needles, sparingly soluble 
 in cold, more easily in boiling water, easily soluble in alcohol, wood-spirit, and chloro- 
 form. It melts at 155 C. and becomes coloured at 200. It dissolves with deep- 
 yellow colour in strong nitric acid ; without colour in sulphuric, hydrochloric, and. 
 acetic acid, It is insoluble in alkalis, appears to unite with baryta, is coloured green 
 by ferric chloride. The alcoholic solution is not precipitated by lead-salts, platinic 
 or mercuric chloride, nitrate of silver, or tincture of galls. 
 
 Colchiceine exerts, sometimes at least, a poisonous action when injected into the 
 stomach. Oberlin states (Compt. rend. liii. 1202), that O'l grm. killed rabbits in 
 12 hours, and 0-05 grm. in a few minutes ; but according to another account (Ann. 
 Ch. Phys. [3] L 114), even 0*5 grm. produced only temporary symptoms. 
 
 COXiCHICXNE. This alkaloid, which is contained in all parts of the Colchicum 
 autumnale, and probably also in other species of colchicum, was discovered by Pell et ier 
 and Caventou (Ann. Ch. Phys. [2] xiv. 69), who however regarded it as identical with 
 veratrine. It was further examined by Geiger and. Hesse, who first, in 1833, 
 (Ann. Ch. Pharm. vii. 274) recognised its separate identity, and has been more 
 recently investigated by Hiibschmann (Arch. Pharm. [3] xcii. 330), Aschoff, 
 ibid. Ixxxix. 4), Bley (ibid. 18), and others. 
 
 Preparation. 1. The bruised seeds of colchicum are macerated with alcoho- 
 containing sulphuric acid; the extract is treated with lime, the filtered liquid sa- 
 turated with sulphuric acid, and the alcohol expelled by distillation. The concen- 
 trated aqueous solution is then decomposed with carbonate of potassium; the pre- 
 cipitate is dried, and dissolved in absolute alcohol ; the solution is decolorised with 
 animal charcoal ; the filtered liquid is evaporated at a gentle heat ; and the alkaloid 
 thus obtained, is purified by repetition of the treatment with alcohol and animal char- 
 coal (Geiger and Hesse). 2. According to Hiibschmann, a larger product is obtained 
 by exhausting the seeds with 3 pts. alcohol of 90 per cent., then distilling off the 
 alcohol, precipitating the residual liquid with carbonate of potassium ; exhausting the 
 dried precipitate with ether, and finally with sulphuric acid, to separate resin ; and re- 
 precipitating with carbonate of potassium. 3. Aschoff boils the comminuted seeds 
 with water, neutralises the decoction with lime-water ; filters after boiling, and eva- 
 porates to the censistence of an extract; then exhausts the extract with alcohol, 
 continuing the process as long as the alcohol acquires thereby a bitter taste. The 
 residue left after the distillation of the alcohol, is dissolved in water and precipitated 
 with tannic acid ; the precipitate is washed and pressed, then dissolved in alcohol, 
 and digested with a sufficient quantity of recently precipitated ferric hydrate at 
 30 C. ; lastly, the filtrate is evaporated, and the residue treated with absolute alcohol, 
 which dissolves out the pure colchicine. 4. Polex exhausts the bruised seeds with 
 a mixture of 4 pts. ether and 1 pt. alcohol, evaporates to dryness, dissolves the 
 residue in water, and purifies the dissolved alkaloid with animal charcoal. 
 
 Bley and Aschoff, obtained from the seeds, as a maximum, 0~2 per cent, of colchicine. 
 
 Colchicine may likewise be prepared by similar processes from the flowers, leaves, 
 and bulbs of the plant. 
 
 Properties. Colchicine crystallises from its alcoholic solution, on addition of water, 
 in colourless prisms and needles : the alcoholic or ethereal solution leaves it, on evapo- 
 ration, in the form of a transparent varnish (Gcigor). According to other chemists, 
 colchicine is always obtained as an amorphous yellowish white powder. It has a 
 persistently bitter taste, not burning like that of veratrine ; it is inodorous, and does not, 
 
COLCHICUM AUTUMNALE. 1081 
 
 like veratrine, excite sneezing. According to Geiger, it has a very faint alkaline 
 reaction, reddening rhubarbarin, and bluing reddened litmus paper. According to 
 Bley, Aschoff, and Hiibschmann, on the contrary, it is perfectly neutral. It is per- 
 manent in the air. 
 
 The composition of colchicine has not been satisfactorily determined. According 
 to Bley, it contains 55'0 per cent. C, 7*4 H, and 13'0 N, which he represents by the 
 empirical formula C 3 ' r H 30 N 3 O n , although his results agree better with C^'H a N 3 O lo t 
 or C 15 H 23 N 3 5 . Aschoff found 55-2 C, 6'2 H, and 2-8 N, whence he deduces the 
 formula C^JP'NO 11 . The great difference in the nitrogen determinations, and certain 
 differences in the properties of the base, as observed by these two chemists, seem to 
 show that they must have been operating, either upon different bases, or on the same 
 in very different degrees of purity. 
 
 Colchicine dissolves with moderate facility in water, according to Hiibschmann, in 
 less than 2 pts. at 22 C. ; this property distinguishes colchicine from veratrine, which is 
 insoluble in water. It dissolves easily in alcohol, less easily in pure ether ; at 20 C., 
 in 18 pts. ether of specific gravity 074. Chloroform dissolves it readily, and with- 
 draws it for the most part from the aqueous solution on agitation. 
 
 Colchicine, when strongly heated, melts and decomposes with intumescence (according 
 to Bley, it volatilises at 112 C.). Strong nitric acid colours it deep violet or blue, 
 quickly changing to olive-green and yellow ; strong sulphuric acid colours it yellowish- 
 brown, not violet, thus affording a distinction from veratrine. Phosphoric acid and 
 hydrochloric acid colour even dilute solutions of colchicine distinctly yellow ; chromic 
 acid colours the solution green. Chlorine-water renders the solution turbid, and on 
 subsequently adding ammonia, it assumes a yellowish-red colour. Colchicine is pre- 
 cipitated of a kermes-brown colour from its aqueous solution by tincture of iodine ; 
 yellow by dichloride of platinum, white by tannic acid, the last-mentioned precipitate 
 being soluble in alcohol, acetic acid, and alkaline carbonates. 
 
 The statements of different chemists regarding the behaviour of colchicine with 
 bases and acids do not agree. According to Aschoff, colchicine is converted by caustic 
 alkalis into a brown resinous mass, soluble in water and alcohol ; it unites with baryta 
 and lime, but does not decompose alkaline carbonates. According to Bley, a solution 
 of colchicine mixed with carbonate of soda, yields by evaporation a non-crystalline 
 mass, free from carbonic acid (?). 
 
 According to Geiger, colchicine neutralises acids completely, forming extremely bitter 
 salts, with rough irritating after- taste ; some of them, the sulphate for example, are 
 crystallisable and permanent in the air. They are very soluble in water and in 
 alcohol, the aqueous solutions yielding with iodine and with tincture of galls the 
 same reactions as the pure base; caustic alkalis precipitate the colchicine from con- 
 centrated, but not from dilute solutions of the salts. Bley and Aschoff did not succeed 
 in preparing crystallisable compounds of colchicine with acids. The salts were acid, 
 and soluble in water and alcohol, excepting the tannate, which is insoluble in water. 
 
 Physiological action. Colchicine is poisonous, even small doses causing violent 
 vomiting and purging ; ^th of a grain killed a cat in twelve hours. Tannin is said to 
 be a good antidote. In cases of poisoning by colchicine, the alkaloid may be detected 
 by treating the stomach and intestines with strong alcohol, evaporating the liquid, 
 and again treating the residue with alcohol, or with alcohol and ether, and again 
 evaporating. Colchicine then remains as an amorphous yellowish mass, which exhibits 
 the above-mentioned reactions with mineral acids, tincture of iodine, and tannic acid. 
 
 COXiCHXCUIVK A.UTTTlVICT.A.XiX!. The root and seeds of this plant are used in 
 pharmacy ; according to Coindot, however, the flowers are more active and to be 
 recommended for the preparation of a tincture. 
 
 The flowers, according to Keithner, contain colchicine in combination with tannic 
 acid, also sugar, pectin, gum, fat, wax, and resin. The dried flowers, without anthers, 
 yield 4'05 per cent, ash (a) ; the dried anthers alone yield 4'15 per cent, ash (b), con- 
 taining in 100 parts : 
 
 Potash 
 Soda . 
 Lime . 
 Magnesia 
 Alumina 
 Ferric oxide 
 
 a. b. 
 
 37'4 40-0 
 
 8-5 6-1 
 
 4-3 2-6 
 
 3-0 6-5 
 
 0-3 trace 
 
 0-5 0-2 
 
 a. b. 
 
 Silicic acid (anhydrous) 7'7 8 
 
 Carbonic . . 22*3 22'5 
 
 Sulphuric . . 3'7 6-2 
 
 Phosphoric . . 10-6 14-4 
 
 Chlorine . . 1'5 0'5 
 
 The ripe seeds collected in July contain in 100 pts., according to Bley : 0'2 colchi- 
 cine, 5 glucose, and 6 fixed oil, together with resin, extractive matter, cellulose, and 
 traces of veratric acid and gallic acid. 
 
 The fresh bulbs contain, according to the same authority, 0*2 per cent, colchicine, 
 
1082 COLCOTH AR VITRIOLI COLLIDTNE. 
 
 0*3 sugar, 0'5 colouring matter, 29'0 starch, together with gallic acid, extractive 
 matter, cellulose, &c. Colman found also 21 per cent, starch. The starch may be ex- 
 tracted from the bulbs by washing with water ; after prolonged washing, it is perfectly 
 pure and tasteless. (Handw. d. Chem. ii. [3] 153). 
 
 COXiCOTBAR VITRIOLI, also called Crocus Martis. The brown-red oxide of 
 iron which remains after the distillation of sulphuric acid from sulphate of iron ; it is 
 used as a polishing powder. 
 
 COXiIiETIIW. A crystallisable bitter principle, obtained from Colktia spinosa 
 (order Ehamnaccce'). It forms needles insoluble in cold water and ether, sparingly 
 soluble in boiling water, easily in alcohol. It is contained in the alcoholic tincture of 
 the plant, which, according to v. Martius, is used in Brazil as a remedy for inter- 
 mittent fever. (Handw.) 
 
 C 8 H U N. An alkaloid found, together with many others, among 
 the products of the dry distillation of animal substances and of coal. It was discovered 
 by Anderson in 1855 (Phil. Mag. J. [4] ix. 145, 214), who obtained it from bone-oil, 
 and was afterwards found by Greville Williams in the bituminous shale of Dor- 
 setshire (Chem. Soc. Qu. J. vii. 97), in coal tar, and in the impure quinoline obtained 
 by the dry distillation of quinine and cinchonine (Chem. Gaz., 1855, p. 308). It is 
 isomeric with ethyl-phenylamine, ethyl-picoline, dimethyl-phenylamine, and xylidine. 
 
 Preparation. 1. The portion boiling above 170 C. of the mixture of volatile bases 
 obtained from bone-oil (i. 625), is mixed with a considerable quantity of strong nitric 
 acid, which acts very violently upon it, thereby acquiring a deep red colour, and on 
 boiling evolves nitrous acid fumes and an odour of bitter almonds. The part boiling 
 at 182 C. must be well cooled while being mixed with the nitric acid, to prevent ex- 
 plosion. The acid solution, when mixed with water, becomes turbid, from the separation 
 of a reddish-yellow oil, which seems to be impure nitro-benzene ; the acid solution is 
 filtered through moist paper, and the filtrate is boiled for some time to expel the last 
 traces of the neutral oils, then saturated with potash and distilled. The oil which 
 passes over with the water is repeatedly rectified, and the portion boiling between 
 178 and 180 is collected. The part of the mixture of bases boiling above 170 con- 
 tains a considerable quantity of phenylamine, which cannot be removed, either by 
 repeated rectification or by recrystallisation of the oxalate ; by the action of nitric acid 
 it is destroyed, whilst the alkalis homologous with ccllidine remain undecomposed. 
 The part boiling between 172 180, when treated in this manner, yields, by distilla- 
 tion with potash, an oil which begins to boil at 160, and is composed for the most 
 part of lutidine; while the portion boiling above 180 yields an oil, the greater part of 
 which goes over at 179, and when rectified yields pure collidine. (Anderson.) 
 2. When the mixture of ch incline with other bases, which is obtained by the dis- 
 tillation of cinchonine with potash, is subjected to oft-repeated fractional distillation, 
 the portion boiling between 177 and 182 C. yields, with solution of platinum, chloro- 
 platinate of collidine. This salt may also be obtained from the fraction boiling be- 
 tween 182 ar.d 187, if another base mixed with it has previously been destroyed by 
 means of nitric acid. (G-r. Williams.) 
 
 3. Gr. Williams mixes the naphtha obtained by the distillation of the bituminous 
 shale of Dorsetshire with sulphuric acid; boils with water until all the tar is con- 
 verted into resin, and all the pyrrol is removed ; concentrates the liquid ; neutralises 
 with lime or potash, and distils ; supersaturates the distillate with hydrochloric acid ; 
 removes the non-basic oil ; then supersaturates the acid liquid with lime or potash, 
 and distils. The distillate is freed from ammonia by washing with strong potash, 
 dried by solid hydrate of potash, and fractionally distilled until liquids of constant 
 boiling points are obtained. The small portion which passes over between 132 and 
 138 C. is lutidine mixed with a little picoline (from the mother-liquor of the chloro- 
 platinate of lutidine, the double salt of picoline is obtained) ; the portion obtained 
 between 149 and 155, and between 177 and 182 is pure lutidine ; and that which 
 passes over between 227 and 258 is collidine. 4. The mixture of volatile bases ob- 
 tained in like manner from coal-tar oil is treated, as in Anderson's process, with 
 nitric acid, and subjected to repeated fractional distillation. The portion which distils 
 between 150 and 155 C. is lutidine, and afterwards a small quantity of collidine 
 passes over. (Gr, Williams.) 
 
 Properties. Collidine is a colourless, oily liquid, having a strongly aromatic, not 
 unpleasant odour. Specific gravity, 0-921 ; boiling point, 179 C. It forms white fumes 
 when a glass rod moistened with hydrochloric acid is held over it. It is insoluble in 
 water, but takes up a small quantity of that liquid, which it gives up again to hydrate 
 of potassium. It dissolves readily in alcohol, ether, and oils, both fixed and volatile. 
 
 Collidine dissolves readily in acids, but does not neutralise them. It does not pre- 
 cipitate the salts of barium, calcium, magnesium, manganese, or nickel, but throws down 
 
COLLINIC ACID COLLODION. 1083 
 
 alumina, chromic oxide, oxide of zinc, ferric oxide, and mercurous oxide from their 
 solutions : it also precipitates nitrate of lead, but not the neutral acetate. (Anderson.) 
 
 Chloromercurate of Collidine is obtained as a white, curdy, flaky precipitate, and 
 crystallises from hot water in needles. The chloroplatinatc, C 8 H"N.HCl.PtCl 2 , forma 
 orange-yellow flakes. (Anderson.) 
 
 Ethyl -colli dine, C 10 H 13 N = C 8 H IO (C 2 H 5 )N. The hydriodate of this base is 
 obtained as an oily liquid by heating collidine to 100 C. with iodide of ethyl. On 
 decomposing it with nitrate of silver, removing the excess of silver by hydrochloric 
 acid, and mixing the filtered liquid with dichloride of platinum, the chloroplatinate, 
 C 10 H 15 N.HCl.PtCP is obtained, as a finely-divided, crystalline, sparingly soluble preci- 
 pitate (Anderson, Phil. Mag. [4] ix. 221). 
 
 COLLI1MIC ACID. C ti H 4 8 = g 0. (Frohde [1860], J. pr. Chem. Ixxx. 
 
 344). An acid belong to the aromatic series C n II 2n - 8 2 , found among the products of 
 the oxidation of the albuminoi'dal substances, and of gelatin. To obtain it, the mixture 
 of acids produced by oxidising gelatin with chromic acid is saturated with carbonate 
 of sodium, and evaporated to drive off the neutral volatile bodies; the nearly dry salts 
 are decomposed by sulphuric acid ; and the solid acid thereby separated is filtered and 
 washed. If the residue be then treated with a small quantity of boiling water, the 
 greater part of the collinic acid remains in fused reddish masses (about 0-96 grm. 
 collinic acid from 1 kilogrm. gelatin), while the other acids, especially the benzoic acid, 
 dissolve completely, together with a small portion of the collinic acid. By recrystal- 
 lisation from water, it may be obtained in small crystals having a prismatic aspect. 
 
 Collinic acid has a sour, pungent taste ; dissolves sparingly in boiling water, easily 
 in ether. When heated with water, it melts at 97 C, and then solidifies at 93 or 
 94; in the dry state, it does not melt till heated somewhat above 100. On cooling, 
 is solidifies to a waxy mass generally having a radiate texture. At a higher tem- 
 perature, it sublimes. When set on fire, it burns with a bright but smoky flame. 
 Boiled with carbonate of sodium, it yields humoid flakes. Heated with hydrate of 
 potassium, it decomposes, but does not appear to yield any volatile acids. 
 
 Collinic acid is a strong acid, dissolving in caustic alkalis, and decomposing car- 
 bonates. It forms both neutral and basic salts. The silver-salts decompose with 
 facility. 
 
 A solution of collinate of ammonium gives off ammonia and becomes acid on boiling ; 
 acid vapours, however, escape at the same time. The barium-salt, 2C 6 H 3 Ba0 2 + aq., 
 is crystalline, easily soluble in water, gives off water of crystallisation when heated, 
 melts and blackens at a higher temperature. The ferric salt is a light, yellowish-red 
 precipitate, which dissolves with blood-red colour on addition of a small quantity of 
 acid. The neutral silver-salt, OIPAgO 2 , is obtained in crystalline scales by precipi- 
 tating the ammonium-salt with nitrate of silver, dissolving the precipitate in water, 
 and evaporating over oil of vitriol. The mother-liquor when evaporated gives off acid 
 and yields grey granules of a basic salt, Ag 2 0.2C 6 H 3 Ag0 2 ; by continued heating of 
 the solution, the silver-salt is reduced. 
 
 An acid isomeric, if not identical with collinic acid, is produced by oxidising coal- 
 tar naphtha with dilute nitric acid (De La Kue and Miiller, Chem. Soc. Qu. J. xiv. 
 54), or sulpho-benzolic acid with chromic acid. (Church, ibid. 53.) 
 
 COLLINIC AXiDEHYDfi. Hydride of colly 1. This compound occurs, accord- 
 ing to Frohde (J. pr. Chem. Ixxx. 325), among the neutral volatile products of the 
 oxidation of the albumoids, and of gelatin ; it appears to have been previously noticed 
 by Schlieper and Guckelberger. It is probably C 6 H 6 (isomeric with phenic acid). It 
 has not yet, however, been obtained pure, especially not free from hydride of benzoyl. 
 It is a colourless viscid oil, smelling somewhat like oil of cinnamon, and turning yellow 
 from oxidation when exposed to the air. By prolonged boiling with potash-ley, it is 
 converted into collinic acid. By continued contact with ammonia, it is converted into 
 a white crystalline substance, probably the homologue of hydrobenzamide. 
 
 According to Schlieper (Ann. Ch. Pharm. lix. 22), this oil having the odour of 
 cinnamon is converted by the action of dry chlorine, with elimination of hydrochloric 
 acid, into a white substance which is insoluble in ether, and when heated with potash- 
 ley forms a blood-red volatile oil ; the potassium-salt, on addition of an acid, emits 
 the odour of phenic acid. 
 
 COXiXiODXOXT (from Ko\\d>^s, glutinous). A solution of pyroxylin (gun-cotton) 
 in ether. The solubility of this substance in ether, varies considerably according to 
 the mode of its preparation ; the most explosive kinds are by no means the most 
 soluble (see PYROXYLIN). The best mode of obtaining pyroxylin, for the preparation 
 of collodion, is to mix 16 pts. of nitrate of potassium with 12 pts. of common and 
 12 pts. of fuming oil of vitriol ; immerse in this mixture, as soon as it is made, 1 pt. of 
 cotton wool, stir it about for five minutes, and then wash it well with water. 
 
1084 COLLYL, HYDRIDE OF COLOCYNTHIN. 
 
 To prepare collodion, pyroxylin obtained in the manner just described is shaken up 
 with 16 pts. ether, in a bottle which can be closed. 1 or 2 pts. of absolute alcohol are 
 added after a while, and the vessel shaken at intervals, till the solution is complete. 
 Lassaigne pours 26 pts. of ether on 1 pt. of pyroxylin, and mixes the resulting 
 jelly with 18 pts. more of ether. According to other methods, 1 pt. of pyroxylin is 
 treated with from 20 to 120 pts. of ether, and from 4 to 16 pts. of alcohol. The solu- 
 tion obtained by either of these methods is left to stand till the un dissolved parts 
 have settled down. 
 
 Pyroxylin is said also to be rendered perfectly soluble in ether by moistening it 
 with acetone. 
 
 Collodion is a clear colourless gummy liquid, insoluble in water and alcohol, but 
 soluble in ether ; when exposed to the air, it soon dries up, leaving a transparent or 
 translucent residue, which becomes strongly electric by friction, explodes less easily 
 by heat, pressure, or percussion than flocculent pyroxylin, and is soluble in ether con- 
 taining alcohol and in strong acetic acid. 
 
 When the ethereal solution is suffered to evaporate in a thin film, it dries up quickly 
 to a thin transparent membrane, which possesses great adhesiveness, is tolerably im- 
 pervious to air, and is not dissolved either by water or by alcohol. These properties 
 render collodion very useful for a variety of purposes. It is employed with great 
 advantage in surgery to form an air-tight covering for wounds and burns; when 
 spread over an incised wound, it greatly promotes the healing by drawing the edges 
 of the wound together, the film of collodion contracting strongly as the ether evapo- 
 rates. As the collodion film is rather solid, and has but little elasticity, it has been 
 recommended to melt 2 grms. of Venice turpentine with 2 grms. castor oil and 2 grms. 
 of white wax, mix the fused mass with 6 grms. of ether, and add the whole to 
 140 grms. of collodion. 
 
 Collodion is also used as an envelope for caustic substances, in order to confine their 
 action exactly to the desired spot. Pills may be coated with it, so as to render them 
 tasteless, and wood, paper, and other fabrics may be rendered water-proof by being 
 covered with it. 
 
 Collodion is also largely used in photography. A thin layer of the solution, mixed 
 with iodide, bromide, or chloride of potassium, or ammonium, is spread uniformly over 
 a glass plate, then treated with a solution of nitrate of silver to form the sensitive 
 film. It appears to be essential to use anhydrous ether and alcohol for the solvent, in 
 order to insure uniform evaporation. 
 
 Another application of collodion is for making balloons. For this purpose, a 
 solution of collodion, not too thick, is poured into a flask of suitable dimensions, which 
 is turned about to spread the liquid uniformly over it, and then inverted to allow tho 
 excess to run out. The ether is now evaporated from the film of liquid which adheres 
 to the glass, by blowing into the flask with a pair of bellows, whereby the collodion is 
 left in the form of a thin membrane on the surface of the glass. To remove it, the 
 edges of the film are loosened from the glass, a glass tube of suitable character is in- 
 serted into the neck of the flask, so that the balloon may adhere to it, and the air is 
 slowly drawn out with the mouth ; the balloon then detaches itself from the vessel, 
 contracts, and is easily withdrawn through the neck. It must be immediately blown 
 out and tied at the neck, so that it may dry in the distended state. Small and thin 
 balloons do not diminish much in volume as they dry ; but larger ones contract strongly : 
 this contraction may, however, be prevented by drying the balloon in warm air. Collo- 
 dion balloons may be made much lighter than those of gold-beater's skin, so that much 
 smaller ones will rise in the air when filled with detonating gas (2 vol. H and 1 vol. 
 O). They may be made so thin that a balloon containing 100 cubic centimetres 
 shall weigh only 0*03 grms. when empty, and 0*04 when filled with hydrogen ; now the 
 weight of an equal volume of air is 0*13 grms., consequently such a balloon will rise 
 rapidly in the air. Hydrogen diffuses quickly through their pores. Collodion balloons 
 become strongly electric by slight friction ; when very thin, they exhibit beautiful 
 interference-colours. (Handw. d. Chem. ii. [2] 158). 
 
 COXAYXi, HYDRIDE OP. See CoLLINIC ALDEHYDE. 
 
 COX.I.YRITE. A hydrated silicate of aluminium, 2Al 4 3 .Si0 2 + lOaq., found at 
 Ezquerra in the Pyrenees, near Schemnitz in Hungary, and near Wessenfels in Saxony. 
 It is white, very soft, earthy, unctuous to the touch, adheres strongly to the tongue. In 
 water it becomes transparent and crumbles to pieces : it dissolves in acids and the 
 solution yields a jelly by evaporation (Grm. iii. 411.) 
 
 COXiOCYWTHIW. A bitter substance contained in the pith or pulp of the fruit 
 of Cucumis colocynthis (bitter apple), a plant growing wild in the Grecian Archipelago, 
 also in Egypt, and other parts of North-eastern Africa. It has been examined by 
 Vauquelin (J. Phys. Ixxxiv. 338), Braoonuot (J. Pharm. x. 416), Herberger 
 
COLOCYNTHITIN - COLOMBIN. 1085 
 
 (Buchnafa Repert. xxxv. 368), B as tick (Pharm. J. Trans, x. 289), and lastly by 
 Walz (Arch. Pharm. xcvi. 241 ; xcix. 338), who regards it as a glucoside = C 56 H 8I 0'- H . 
 
 It is prepared from the pulp of the fruit separated from the seeds. Vauquelin ex- 
 hausted the pulp with cold water, and evaporated the extract, the colocynthin then 
 separating in oily drops, which solidified on cooling. Leb our dais (Ann. Ch. Phys. 
 [3] xxiv. 58) precipitates the aqueous extract with neutral acetate of lead, and treats 
 the filtered liquid with animal charcoal, which takes up both the colouring matter and 
 the bitter principle. The charcoal is then washed with water. As long as the liquid 
 which runs through it acquires a bitter taste, nothing but pure colocynthin is dissolved ; 
 and on again precipitating it with animal charcoal, boiling the charcoal with alcohol, 
 and leaving the solution to evaporate, the colocynthin separates in small warty 
 groups. Walz exhausts the fruit with alcohol of 0*840 ; evaporates ; dissolves the 
 extract in water ; precipitates the filtrate with neutral and with basic acetate of lead ; 
 removes the lead from the filtered liquid by sulphuretted hydrogen ; and precipitates 
 the colocynthin by tannic acid. The precipitate, which becomes resinous on heating 
 the liquid, is dissolved in alcohol ; the tannic acid is precipitated with basic acetate of 
 lead ; the filtrate, freed from lead, is heated with animal charcoal ; the liquid is 
 again filtered and evaporated ; and the dry residue exhausted with ether, which leaves 
 the colocynthin undissolved. 
 
 Colocynthin is intensely bitter, and acts as a drastic purgative. It is soluble in 
 water, alcohol, and ether. The aqueous solution is precipitated by chlorine ; it also 
 yields, with acids and with deliquescent salts, a viscous precipitate insoluble in water. 
 The solution is also precipitated by acetate of lead and many other metallic salts. 
 
 Colocynthin boiled with acids is resolved, according to Walz, into sugar (7 '1 per 
 cent.) and colocynthein, C 40 H 54 13 , which remains as a resinous mass, and may be 
 purified by washing with water, solution in absolute ether, and evaporation. 
 
 COIiOCYWTHITIW. A body contained, according to Walz (N. Jahrb. Pharm. 
 ix. 225), in the alcoholic extract of bitter apple (see CUCUMIS). When this extract is 
 treated with water, colocynthitin remains undissolved ; and on treating this residue 
 with ether, digesting the solution with animal charcoal, evaporating the filtrate, 
 exhausting with hot absolute alcohol, and leaving the filtered liquid to cool, colo- 
 cynthitin separates in white microscopic crystals. It is soluble in ether. 
 
 COIiOIYIBIC ACID. An acid obtained by Bodecker (Ann. Ch. Pharm. Ixix. 
 47), from colombo-root, the root of Mcnispermum palmatum, L., Cocculus palmatis, Dec. 
 To prepare it, the alcoholic extract of the root is exhausted with water or lime-water, 
 and the solution treated with hydrochloric acid. Colombic acid is then precipitated in 
 white amorphous flakes, which are strongly acid, nearly insoluble in cold water, very 
 soluble in alcohol, sparingly soluble in cold ether. By the evaporation of its alcoholic 
 solution, it is obtained in the form of a yellow varnish. 
 
 The alcoholic solution of colombic acid is not precipitated by acetate of copper, but 
 yields with neutral acetate of lead a copious white precipitate, which, when dried at 
 130 C contains 30*53 per cent, lead oxide, agreeing nearly with the formula 
 3Pb 2 0.2C 42 H 44 12 . Dried at 100 C., it contains in addition 5H-0. 
 
 The acid itself, dried at 115 C., gave by analysis 66 64 per cent. C, and 6-29 H, 
 agreeing nearly with the formula C 42 H 4B 13 , or C 42 H 44 1;2 .H 2 0. 
 
 COX.OIKBXN-. Colombo Bitter. C 21 H 22 Of.- (Wittstock [1S30], Pogg. Ann. 
 xix. 298. Liebig, ibid. xxi. 30. Bodecker, Ann. Ch. Pharm. Ixix. 39.) A neutral 
 substance which constitutes the active principle of Colombo root. Bodecker prepares 
 it by exhausting the root with alcohol of 75 per cent., drying the extract as completely 
 as possible, dissolving it in water, agitating the solution several times with an equal 
 volume of ether, decanting the ethereal liquid with a siphon, filtering, and evaporating 
 off the greater part of the ether. The colombin then crystallises out, and is purified 
 by rinsing it with cold ether, pressing it between bibulous paper, dissolving it in boil- 
 ing absolute ether, and concentrating the solution to one-fourth of its bulk. The 
 greater part of the colombin then separates out quite white, the rest remaining dissolved 
 in the ether, together with the fat contained in the root. To free the colombin en- 
 tirely from fat, it imist be repeatedly crystallised from ether; when quite pure it will 
 dissolve in acetic acid without separation of oil-drops. 
 
 Colombin crystallises in colourless prisms belonging to the trimetric system. Ob- 
 served combination, oo P . ooP oo . GO P oo . P oo. Inclinations of the faces, oo P : ooP => 
 125 30': oo P: oo Poo = 152 45'; oo P : oo Poo = 117 15'; P oo : P oo = 176 1^; 
 P oo : oo P oo = 123 39-5' ; oo P : P oo = 119 31'. The faces are brilliant, but the 
 crystals do not cleave in any direction (G-. Kose, Pogg. Ann. xix. 441). Coiombin 
 is inodorous, very bitter, and perfectly neutral to vegetable colours. It melts at a 
 gentle heat. It dissolves but sparingly in cold water, alcohol, and ether, but imparts to 
 them a strong bitter taste. Boiling alcohol of specific gravity 0'835 dissolves from ~-^ 
 
1086 COLOMBO ROOT COLOPHILENE. 
 
 of its weight of colombin. It dissolves to a small amount in volatile oils, and 
 freely in potash, whence it is precipitated by acids in its original state. Acetic 
 
 to 
 
 more 
 
 acid dissolves it and deposits it in the crystalline state on evaporation. Strong sul- 
 
 phuric acid dissolves it with orange colour, gradually changing to deep red, and on 
 
 adding water to the solution, brown flakes are deposited. Solutions of colombin are 
 
 not precipitated by any metallic salts or by tincture of galls. 
 
 Colombin yields, according to the mean of Bodecker's analyses, 65-20 per cent. C and 
 5-98 H, the above formula requiring 65'3 C, 57 H, and 29'0 O. It does not form any 
 definite compound, so that its atomic weight cannot be determined. 
 
 COLOMBO ROOT. The root of Cocculus palmatus, Dec., contains colombin, 
 berberine, colombic acid (probably as colombate of berberine), besides starch, colour- 
 ing matter, &c. The colombic acid and berberine may perhaps be formed from co- 
 lombin by addition of the elements of ammonia (Bodecker) : 
 
 4C 21 H 22 7 + 2NH 8 = 2C 21 H 19 N0 5 + C I2 H 46 13 + 6H 2 0. 
 Colombin. ' Berberine. Colombic 
 
 acid. 
 
 The root acts with violence on the animal organism ; a grain of the dry extract pre- 
 pared with ether and freed by water from fat and wax, killed a rabbit when intro- 
 duced into a wound. This active property appears to be due to the colombin. 
 (Buchner.) 
 
 COLOPHAMTE. A constituent of icica resin (q. v.), containing, according to 
 Scribe (Compt. rend. xix. 129), C 2I H 30 2 . It is yellow, amorphous, easily soluble in 
 alcohol, melts above 100 C., is insoluble in aqueous alkalis, and reacts neutral. 
 
 COIOPHENE. C"H 32 or <7ff 32 . (H. Deville, Ann. Ch. Phys. [2] Ixxv. 66; 
 [3] xxvii. 85.) A hydrocarbon polymeric with oil of turpentine, obtained by distilling 
 that oil with strong sulphuric acid, or by distilling hydrate of turpentine-oil with 
 phosphoric anhydride. In either case, terebene (C 10 H 16 ) passes over first ; afterwards, 
 when the heat rises above 210 C. colophene distils ; it is purified from sulphur and a 
 substance resembling colophony by repeated rectification, at last over antimonide of 
 potassium. It may also be obtained by the rapid distillation of colophony, the 
 product being purified in like manner. 
 
 Colophene is an aromatic oil, colourless by transmitted light, and exhibiting by 
 reflected light a dark indigo-blue iridescence. Specific gravity, 0'940 at 9 C., 0-9394 
 at 25. Boiling point between 310 and 315. Vapour-density = 11-13 (probably 
 only twice as great as that of oil of turpentine, therefore = 9-526). Refracting 
 power = 1-517 (Becquerel and Cahours), 1*5212 (Deville). It has no action on 
 polarised light. 
 
 Colophene absorbs chlorine gas without evolution of hydrochloric acid, becoming 
 hot, and changing to a resin like colophony, which separates in yellow spherules from 
 its solution in absolute alcohol. If, when the absorption of chlorine has ceased, the 
 product be heated to fusion in the stream of chlorine, a large quantity of hydro- 
 chloric acid is evolved, and Deville's chlorocolophene = C 20 H 24 C1 8 is formed, which how- 
 ever still contains a resin removable by alcohol, and when distilled, gives off hydro- 
 chloric acid, yields a distillate of colophene and hydrochlorate of colophene, and leaves 
 charcoal. 
 
 Hydrochlorate of Colophene. Colophene absorbs hydrochloric acid gas, with rise of 
 temperature, and acquires an indigo-colour. The hydrochlorate gives up nearly all 
 its hydrochloric acid when treated with chalk, and when distilled with baryta, yields 
 Deville's colophilcne = C 20 H 32 , which does not exhibit the dichroism of colophene, 
 and has a refracting power for light = 1-5175. (Deville, Becquerel, and Cahours, 
 Pogg. Ann. li. 427-433.) 
 
 Colophene from Camphor. (Claus, J. pr. Chem. xxv. 266. When camphor is 
 distilled with an equal weight of iodine, hydriodic acid is evolved, camphin passes over 
 at 180 C., and charcoal, iodine, campho-creosote and colophene remain behind (i. 728). 
 On increasing the heat, the two latter substances distil over as a bluish-green oil, 
 which is deprived of its creosote odour by agitation with potash, but cannot be ob- 
 tained quite pure, even by distillation over lime and finally over potassium. 
 
 It is a thick, yellowish oil, with violet iridescence, having a high boiling point, a 
 mild taste, and an odour of violets, and burning with a bright fuliginous flame. It is 
 perhaps identical with colophene from oil of turpentine or from colophony. 
 
 It is not soluble in water or in weak alcohol, but dissolves in ether, oil of turpentine, 
 rock-oil, and camphinc. When 2 drops of it are dissolved in 2 drachms of alcohol, 
 the solution, after agitation with animal charcoal, exhibits a fine dark blue colour 
 by reflected light. 
 
 COIiOPHXIiElTE. The hydrocarbon C 20 !! 32 obtained from Deville's hydro- 
 chlorate of colophene (vid. sup.) 
 
COLOPHOLIC ACID COLOPHONY. 1087 
 
 COZiOPHOXiXC ACID of Unverdorben ; y-resin of Colophony of Berzelius. The 
 constituent of colophony which is least soluble in alcohol, and is produced by the 
 action of heat on pinic acid. It is therefore present in colophony in variable quantity, 
 according as that substance has been more or less heated during fusion ; the darker 
 varieties contain about one-tenth. Colopholic acid is said to be likewise produced 
 when pinic acid is distilled till a third of it has passed over. 
 
 Colopholic acid is brown, sparingly soluble in alcohol of 67 per cent., more readily 
 in presence of pinic acid. It has a stronger affinity for bases than pinic acid ; never- 
 theless the colopholates exactly resemble the pinates. 
 
 COXiOPHOXTXC ACIDS. The resinous acids, pinic, pimaric, sylvic and colo- 
 pholic, which are present in colophony. 
 
 COXiOPHOXJZTE. A variety of garnet, so called from its brown colour, resinous 
 lustre, and easy fusibility. (See GARNET.) 
 
 COXiOPHONOXTE. C n H 18 0.(Schiel, Ann. Ch.Pharm. cxv. 96). An oil occurring 
 among the more volatile products of the dry distillation of colophony ; it is separated 
 by fractional distillation. It is colourless, mobile, highly refractive, of specific gravity 
 0-84, boils at 97 C.; vapour-density about 5*1. When heated above its boiling point 
 in a close vessel, it turns brown, and emits an odour of peppermint. It mixes with 
 sulphuric acid, and on addition of water, a green oil separates, having an odour of 
 thyme and rosemary. Hydrochloric acid acts in like manner ; nitric acid converts it 
 into a resin. With potassium, it gives off gas, and is converted into a brown mass, 
 subsequently turning yellow. 
 
 COLOPHONY. Rosin, Colophonium, Colophane, Arcanson, Brai sec, Geigenharz. 
 The resinous substance which remains when turpentine or pine-resin is heated till 
 the water and volatile oil are expelled. It is for the most part a mixture of several 
 resinous acids, viz., pinic acid (the a-resin of Berzelius), which forms the principal 
 part, sylvic acid (-resin), and Colopholic acid (y-resin), sometimes also pimaric acid. 
 These acids, which are mixed in various proportions, are all isomeric, their common 
 formula being C 20 H 30 2 or C^H^O*. They are perhaps formed by oxidation of tur- 
 pentine oil : 
 
 2C 10 H 16 + O 3 = C 20 H 30 2 + H 2 0. 
 
 Colophony is either pale yellow and transparent (C. album) or brownish -yellow and 
 translucent (C. commune), according to the degree of heat to which it has been ex- 
 posed. By distillation with steam under a pressure of about ten atmospheres, it may 
 be obtained very nearly colourless (Hunt and Pochin's Patent, 1858, No. 925). It 
 has a vitreous lustre, is brittle in the cold, has a conchoidal fracture, and yields a 
 yellowish powder. Its specific gravity varies from TO? to T08. It is insoluble in 
 water, but dissolves easily in alcohol, ether, wood-spirit, and oils both fixed and 
 volatile. Eock-oil dissolves only a portion of it ; the undissolved part is said to be 
 identical with pinic acid altered by the action of the air. Nitric acid dissolves and 
 decomposes it at the same time. 
 
 Colophony, being a mixture of acids, unites with bases. The compounds which it 
 forms with the alkalis are soaps soluble in water. It is easily saponified either by 
 caustic alkalis or by their carbonates. 
 
 Colophony softens at 69 or 70 C. and melts at 135. At a higher temperature 
 it gives off volatile oils, acquiring a darker colour, and yields colopholic acid. 
 When quickly heated in a retort, it distils partly undecomposed, partly resolved into 
 gases, volatile oils, viz. Deville's terebene and colophene, and perhaps other hydro- 
 carbons, finally yielding viscid oils, with a small residue of carbonaceous matter. When 
 the distillation is performed on the large scale in cast iron retorts, the gases evolved in 
 the first half of the distillation contain, besides the constituents of the air, 15 per 
 cent, carbonic anhydride, 11'5 carbonic oxide, 5'9 ethylene and tetrylene ; at a higher 
 temperature, the oxygen disappears, the proportion of carbonic anhydride increases, 
 and lastly a small quantity of marsh-gas is formed. The first portion of the liquid 
 distillate is a yellow, mobile, strong-smelling liquid, known in commerce as isscnce of 
 rosin (vive essence, Harzcsscnz) ; it yields by fractional distillation, first colophonone 
 (q. V.), and afterwards an optically indifferent camphene (i. 724), boiling at 160 C., 
 having the odour and other properties of oil of turpentine, and perhaps identical with 
 Deville's terebene. At a later stage of the dry distillation, a viscid fluorescent oil 
 passes over, called rosin-oil or paraffinc-oil, which, after being treated with quick-lime, 
 corresponds in composition to the formula C 30 H 40 0. After rectification, it no longer ex- 
 hibits fluorescence, and if again treated with lime, gives the formula C-H'- 8 (Schiel, 
 Ann. Ch. Pharm. cxv. 96)'. At a red heat, colophony yields a mixture of gases burning 
 with a very bright flame, which it has been attempted, though withoiit much success, 
 to use as an illuminating gas. 
 
1088 COLORIMETER - COLOURING MATTERS. 
 
 Colophony is extensively used in making varnishes and cements, in the caulking of 
 ships, in the preparation of plasters and ointments, and as a reducing agent in the 
 soldering of metals. Large quantities are consumed in the manufacture of yellow 
 soap. A well known use of it is for covering the bows of violins, to prevent the bo~w 
 from slipping over the strings without producing vibration. Of the products obtained 
 by the dry distillation of colophony, the more volatile oil is used in place of turpentine- 
 oil, the more viscid rosin-oil for soap-making, and for lubricating cartwheels, &c. 
 (Handw. d. Chem. i. [3] 160.) 
 
 COXtORXnXETER. An instrument for measuring the depth of colour in a liquid 
 by comparison with a standard liquid of the same tint. The comparison is made 
 either by varying the depth of the stratum of liquid under examination till it exhibits 
 the same intensity of colour as the normal liquid, and then measuring the depth of 
 the stratum, or by diluting the stronger-coloured liquid with water, till equal columns 
 of the two exhibit the same depth of colour. 
 
 COXiORXXr. A colouring matter obtained by Kobiquet and Colin from madder, 
 since shown to be impure alizarin. 
 
 COXiQSTRUJVX. The milk of mammalia secreted in the first few days after partu- 
 rition, before the access of milk-fever. It is distinguished from ordinary milk by con- 
 taining a larger amount of solid constituents, also a larger proportion of fat, casein, and 
 milk-sugar. (See MILK.) 
 
 COLOUR. (See LIGHT). A table of oil painters' colours, with notices of their 
 chemical and artistical qualities, drawn up by W. Linton, is given in lire's Dictionary 
 of Arts, Manufactures, and Mines, vol. i. p. 803 ; see also Chimie dcs Couleurs pour 
 la Peintiire a VEau et a FHuile, par. J. Lefort. 12mo. Paris, 1855. 
 
 COLOURING MATTERS. This term is usually restricted to coloured com- 
 pounds of vegetable or animal origin, sometimes more especially to such as exist 
 ready formed in the bodies of plants and animals, or are easily formed from them by 
 natural processes, such as oxidation or fermentation. Accordingly, it would be applied 
 to such bodies as indigo, Indian yellow, and carmine, rather than to compounds like 
 aniline-purple or murexide, which are formed by complicated artificial processes. This 
 restriction of the term must not, however, be regarded as absolute, since many artificial 
 organic coloured compounds resemble the natural colouring matters in their most 
 essential properties, especially in those which render them available as dyes. 
 
 Colouring matters occur in all the organs of plants and animals. Many are obtained 
 from roots, as alkanet, turmeric, madder, &c. ; from the stems, as from sandal-wood, 
 log-wood, Brazil-wood, &c. : leaves, flowers, fruits, and seeds are also rich in colouring 
 matters. Of some insects, as the cochineal-insect, the entire substance is used as a 
 dye ; certain liquids of the animal organism, as the blood and bile, are also strongly 
 coloured. Colouring matters rarely exist either in plants or animals in the separate 
 state ; indeed their separation is often a matter of considerable difficulty. Many do not 
 exist ready formed in plants, but are produced from originally colourless compounds 
 by oxidation or fermentation ; in some instances, also, by the action of oxygen in pre- 
 sence of alkalis. 
 
 Colouring matters are for the most part either red, yellow, or blue, the last being 
 the least numerous. Only one green colouring matter occurs in nature, namely, the 
 chlorophyll of leaves. 
 
 Colouring matters have generally a saccharine and somewhat harsh taste ; they are 
 inodorous, some of them, as indigotin and alizarin, crystallise readily; others are of a 
 resinous character. Many are volatile, as alizarin ; but they must always be distilled 
 with caution, as a heat of 150 C. is often sufficient to decompose tham. 
 
 All colouring matters are affected by light, mostly absorbing oxygen under its in- 
 fluence, and becoming more or less decolorised. The green colour of chlorophyll on 
 the contrary requires the presence of light for its development. 
 
 Many colouring matters are soluble in water, others only in alcohol, ether, or vola- 
 tile oils ; in some cases, the presence of an acid facilitates the solution, although the 
 colouring matter may not actuallv possess basic properties, e.g. hsematosin, indigotin, 
 alizarin, purpurin ; others on the contrary, as carthamin and santalin, dissolve readily 
 in alkalis. 
 
 The tint of colouring matters is modified in various degrees, and sometimes com- 
 pletely destroyed, by chemical reagents. The alkalis turn the naturally red colour of 
 litmus to blue, many vegetable blue colours to green, and the yellow of rhubarb or 
 turmeric to brown. The alkaline compounds of alizarin are of a rich violet colour, 
 though alizarin itself is reddish yellow. All colouring matters are decomposed by 
 concentrated alkalis. 
 
 Many metallic oxides, e.g. alumina and oxide of tin, form chemical compounds with 
 colouring matters. Such compounds are called lakes. Many salts also, especially those 
 
COLUMBITE COMBUSTION. 1 089 
 
 of aluminium, Iron, and tin, act upon colouring matters so as to form compounds by 
 means of which the colouring matter is fixed upon organic tissues ; such substances 
 are called mordants. 
 
 Porous substances, especially animal charcoal, absorb colouring matters without 
 decomposing them ; thus, if an infusion of logwood be decolorised by filtration 
 through animal charcoal, the colouring matter may be recovered by treating the char- 
 coal with a weak alkaline ley. 
 
 All organic colouring matters are destroyed by chlorine in presence of water, the 
 action consisting, in most cases, of a direct oxidation of the colouring matter, by 
 oxygen set free by the decomposition of water. Sometimes, however, the chlorine 
 takes hydrogen from the colouring matter itself and partly replaces it. 
 
 Oxygen in the nascent state likewise acts as a decolorising agent, when derived 
 from other sources ; thus, peroxide of hydrogen quickly destroys the colour of organic 
 bodies, and indigo is bleached by nitrous acid. 
 
 Sulphurous acid decomposes and bleaches many colouring matters, sometimes by 
 abstracting oxygen, sometimes by uniting with the colouring matter and forming a 
 colourless compound. It is a valuable bleaching agent in many cases, especially for 
 silk and wool, because it destroys the colouring matter without acting on the tissue, 
 whereas chlorine would act very injuriously upon it. Fruit stains are easily removed 
 from linen by washing with a weak solution of sulphurous acid, or by holding the 
 moistened cloth over burning sulphur ; care must be taken, however, to wash it well 
 afterwards, or the sulphuric acid produced in the reaction will destroy the fibre. 
 
 Many reducing agents, such as nascent hydrogen, sulphydric acid, alkaline sul- 
 phides, ferrous salts, &c., decolorise colouring matters in such a manner that the colour 
 is restored by mere exposure to the air ; thus, blue indigo is converted into white 
 indigo by the action of these bodies, but recovers its blue colour by atmospheric oxi- 
 dation. The action consists either in a direct deoxidation of the colouring matter, or 
 in a combination of the colouring matter with hydrogen derived from the decomposi- 
 tion of water. Thus white indigo, C 8 H 6 NO, is formed from blue indigo, C 8 H 5 NO, by 
 addition of 1 at. hydrogen. ( Traite de Chimie generate, par Pelouze et Fremy, 2 me ed. 
 v. 492 ; Ure's Dictionary of Arts, Manufactures, and Mines, i. 806.) 
 iiiiTE. See NIOUITE. 
 
 or NIOBIUM. A metal originally discovered in columbite from 
 Massachusetts, and since shown to exist in the tantalite (or rather columbite) of Boden- 
 mais in Bavaria, also in Samarskite, pyrochlore, wohlerite, euxenite, and a variety of 
 pitchblende from Satersdaleu in Norway. It was discovered by Hatch ett in 1801. 
 Wollaston erroneously supposed it to be identical with tantalum, the metal discovered a 
 short time afterwards by Ekeberg in Finland tantalite. This opinion was long received 
 as correct, and columbium is even now spoken of in most Manuals of Chemistry as 
 identical with tantalum ; but the researches of H. Eose have shown that this supposed 
 identity does not exist, In short, columbium is identical, not with tantalum, but with 
 Rose's niobium (q. -v.) 
 
 COMBUSTION. This term properly denotes the development of light and heat 
 accompanying chemical combination. It is sometimes used as synonymous with in- 
 flammation, which, however, is better restricted to those cases of combustion in which 
 the products are gaseous, in other words, in which flame is produced. Ignition is the 
 incandescence of a body produced by extrinsic means, without change of its chemical 
 constitution. 
 
 The earlier chemists, feeling daily the necessity of fire to human existence, and 
 astonished at the changes which this power seemed to produce in charcoal, sulphur, 
 the metals, and other bodies, regarded combustion as the grand and essential pheno- 
 menon of chemistry. At the beginning of the eighteenth century, S t a h 1, of Prussia, by 
 applying the views of Albertus Magnus and Becher respecting combustion to the whole 
 collection of facts discovered by himself and others, and uniting them into a connected 
 whole, laid the foundation of the first system of chemistry. This system received the 
 name of the "Phlogistic Theory," because Stahl assumed that all combustible bodies 
 contain one and the same principle of combustion called Phlogiston, the escape of this 
 substance from a heated combustible body being supposed to produce the phenomenon 
 of combustion or fire, and its addition to a burnt body to restore the combustibility of 
 that body : thus, phosphorus was regarded as a compound of phlogiston and phosphoric 
 acid ; lead of phlogiston and lead-earth or calx of lead, the substance now called oxide 
 of lead. When a calx or earth was reduced to the metallic state by heating it with 
 charcoal (a body rich in phlogiston), it was supposed that the burnt body took phlo- 
 giston from the charcoal, and was thus restored to the combustible state. 
 
 An obvious defect of the phlogistic theory was that it took no account of the essen- 
 tial part which the air plays in all ordinary cases of combustion, a fact suggested by 
 
 VOL. I. 4 A 
 
1090 COMBUSTION. 
 
 common experience, and fully demonstrated by the discoveries of Scheele, Cavendish, 
 and Priestley. Moreover it had long been known that many combustible bodies, the 
 metals for example, do not lose, but gain weight when burnt ; and towards the end of 
 the eighteenth century Lavoisier showed, by experiments on combustion, made with a 
 degree of accuracy in the determination of weights and volumes, quite unknown before 
 his time, that whenever a body burns in the air or in oxygen gas, the oxygen enters 
 into combination with the burning body, and the weight of the product is exactly 
 equal to the sum of the weights of the combustible body burnt and of the oxygen con- 
 sumed. It was also shown that, in the reduction of a metal from its calx (or oxide) by 
 charcoal, the latter body takes oxygen from the calx and leaves the metal in the free 
 state. In short, wherever the phlogistic theory supposed that phlogiston was removed 
 from a body, Lavoisier's experiments showed that oxygen was taken up, and wherever, 
 according to the former theory, phlogiston was supposed to be added, Lavoisier showed 
 that oxygen was removed. This system of chemistry, called the " Antiphlogistic Theory," 
 did not, however, meet with immediate acceptation from the majority of chemists, 
 the advocates of the phlogistic system maintaining that the increase of weight of 
 metals and other bodies in burning might be explained by abscribing to phlogiston a 
 principle of 1 e vity, in other words, a tendency to recede from the earth instead of fall- 
 ing towards it, as ponderable bodies do. Such an assumption, however improbable in 
 itself, would of course suffice for its immediate purpose ; that is to say, of accounting 
 for the increase in weight of a body by loss of phlogiston ; but the explanation thug 
 afforded took no account of the oxygen, which Lavoisier had shown to be abstracted 
 from the air and added to the burning body. Accordingly, as experiments were multi- 
 plied, and it was shown that in all cases of combustion, the weight of the product was 
 equal to the weights of the combining bodies taken together, the phlogistic theory 
 gradually lost its hold on the minds of chemists, and was ultimately abandoned. 
 
 At the time of Lavoisier, attention was chiefly directed to combustions taking place 
 in the air or in oxygen gas, and to the reduction of metallic oxides by hydrogen or 
 carbon. Chlorine also, then called oxymuriatic add, was supposed to contain oxygen ; 
 bromine and iodine were not known. Accordingly it was natural that oxygen should 
 be regarded as essentially the supporter of combustion, the bodies which burned 
 in it being called combustibles. Afterwards, when chlorine was shown to be an ele- 
 mentary substance, and when bromine and iodine were discovered, and metals, &c., 
 were found to burn in their vapours, the term supporter of combustion was extended 
 to all substances capable of forming vapours in which others can burn ; thus, when 
 copper-foil burns in sulphur vapour, the sulphur may be called the supporter, and the 
 copper the combustible. But since the same substance may act sometimes as a com- 
 bustible, sometimes as a so-called supporter, e.g. sulphur as a combustible with 
 oxygen, as a supporter with metals, the distinction has gradually become obsolete. 
 
 The development of heat and light in combustion was attributed, on Stahl's theory, 
 to the escape of phlogiston. The antiphlogistic theory, by dwelling chiefly on the 
 ponderable substance produced by the combustion, and the relation between its 
 weight and those of the combining bodies, tended rather to divert attention from the 
 attendant phenomena of light and heat, and, indeed, was somewhat reproached by the 
 adherents of the older theory for not rendering a sufficient account of those pheno- 
 mena. Lavoisier attributed the heat accompanying combustion to the separation of 
 the latent heat of the oxygen gas ; and attempts have been made to extend this mode 
 of explanation to all cases of chemical combination, in which gaseous or liquid sub- 
 stances pass to the solid state. This, however, will not account satisfactorily for the 
 more intense evolution of heat in combustions and other combinations : for the latent 
 heat of gases and liquids is small in comparison with such developments of heat. 
 Moreover, in many instances, the combination is not attended with condensation ; e. g. 
 in the combustion of charcoal or sulphur in oxygen gas, and of hydrogen in chlorine 
 gas ; or again, gaseous products are formed from solid bodies, great heat being at the 
 same time evolved, as in the explosion of nitre with charcoal, &c. 
 
 Neither can the heat of combustion be generally attributed to diminution of specific 
 heat in the resulting compound ; for in most cases the atoms of simple substances 
 retain their original specific heat when they enter into combination (see ATOMIC 
 WEIGHTS, i. 472, and HEA.T). In other cases, on the contrary, combination is attended 
 with an actual increase of specific heat, so that the result would be a production of 
 cold, if heat were not developed from some other cause. 
 
 Thus, 1 Ib. of hydrogen gas, of specific heat 3'293, combines, under the most violent 
 evolution of heat, with 8 Ibs. of oxygen of specific heat 0-236, producing 9 Ibs. of 
 
 -^ - j = 0-576 as 
 
 the mean of the two specific heats. If then water had a specific heat = 0*576, the 
 quantity of sensible heat in the hydrogen and oxygen gases together would be exactly 
 
COMBUSTION. 1091 
 
 sufficient to bring the water formed to the same temperature as that of the gases them- 
 selves ; but since the actual specific heat of water is I'OOO, the quantity of sensible 
 heat in the gases is not sufficient for this purpose ; and if heat were not developed 
 from some other cause during the combination of oxygen and hydrogen, the water pro- 
 duced would be much colder than the two gases before combination. 
 
 Berzelius, on reviewing these circumstances, justly concluded that all such explana- 
 tions of the origin of fire are defective. He supposed that, in every chemical com- 
 bination, there is a neutralisation of opposite electricities, and that this neutralisation 
 produces the flame or fire, in the same way as it produces fire in the discharges of the 
 Leyden phial and the voltaic battery, and in thunder. He admitted, however, that 
 this hypothesis does not afford a satisfactory explanation of the union of the atoms 
 after the discharge has taken place. (See CHEMICAL AFFINITY, i. 865.) 
 
 A more satisfactory explanation is that advanced by Sir Humphry Davy, viz. that 
 the immediate cause of the phenomena of heat is motion, and that the laws of its com- 
 munication are precisely the same as the laws of the communication of motion ; that 
 in fact, these phenomena are analogous to those of light, as expounded by the undu- 
 latory theory. On this principle we may explain the great heat produced by friction, 
 and in explosions, such as those of oxide of chlorine, and chloride of nitrogen, cases in 
 which heat and light are copiously displayed, at the same time that great enlargement 
 of volume takes place, rendering the idea of the extrusion of a calorific fluid altogether 
 inadmissible. Whenever the chemical forces which determine either composition or 
 decomposition are energetically exercised, the phenomena of combustion, which aro 
 incandescence with a change of properties, are exhibited. In all cases, the heat and 
 light depend on the same cause, and merely indicate the energy and rapidity of the 
 reciprocal chemical attractions. No peculiar substance or phlogistic essence is neces- 
 sary to the production of fire ; but it is a general result of the actions of any bodies 
 possessed of energetic chemical attractions or different electrical relations ; and it is 
 produced in all cases in which an intense and violent motion may be conceived to be 
 communicated to the particles of bodies. 
 
 "We now proceed to consider the circumstances which favour or retard combustion 
 and determine the nature of flame, confining our attention chiefly to cases of combus- 
 tion in the air. For the greater part of our knowledge on this subject we are indebted 
 to the admirable researches of Sir Humphry Davy (Phil. Trans. 1817, pp. 45 and 
 77), which led him to the invention of the Miner's Safety-lamp. The subject may be 
 treated under the following heads : 
 
 1. The temperature and other conditions required to inflame different bodies. 
 
 2. The nature of flame and the relation between the light and heat which compose it. 
 
 3. The causes which modify and extinguish combustion. 
 
 The quantities of heat evolved in the combustion of different bodies will be more 
 conveniently considered in the article HEAT (q. #.) 
 
 I. Conditions of Inflammability. 
 
 But few substances are capable of combining with oxygen at ordinary temperatures, 
 and those which exhibit this capacity lose it at lower temperatures. The temperature 
 required to bring about the combination of oxygen with any substance, the burning 
 point, as it may be called, is different, not only for different substances, but even for the 
 same substance, according as the combustion is to take place rapidly or slowly. Thus, 
 phosphorus combines slowly with oxygen, or exhibits slow combustion at 25 C. (77 F.), 
 but does not enter into rapid combustion till raised to 60 C. (] 40 F.) Charcoal like- 
 wise burns slowly below a red heat. Sulphur takes fire in the air at about 285 C. 
 (550 F.) Most other elementary bodies require to be heated to redness before they 
 take fire in the air or in oxygen gas. Several organo-metallic bodies, as zinc-methyl, 
 cacodyl, and some of the antimonides of ethyl and methyl, take fire immediately on 
 exposure to the air. Nitrogen cannot be made to unite with oxygen by elevation of 
 temperature, except under peculiar circumstances ; chlorine, bromine, and iodine not 
 at all by heat, only by substitution. 
 
 Chlorine unites rapidly with hydrogen at ordinary temperatures, and under the in- 
 fluence of direct sunshine, produces a violent explosion. Many metals also burn when 
 introduced into chlorine at ordinary temperatures. Bromine and iodine unite rapidly 
 with phosphorus and with several metals, especially if in the finely divided state, at 
 ordinary temperatures ; but in a tube cooled with ice, phosphorus and iodine may be 
 brought together without acting on each other. 
 
 Sulphur unites with many metals at a red heat, the combination being attended 
 with vivid incandescence, e. g. with iron and copper. 
 
 The relative inflammability of different bodies in common air may be approximately 
 estimated by fusing a series of globules of different sizes at the ends of thin iron wires, 
 
 4 A2 
 
1092 COMBUSTION. 
 
 and lighting a number of very small flames of different substances, but all of the 
 same size. A globule , of an inch in diameter brought near an oil flame i of an inch 
 in diameter will, if cold, extinguish it at the distance of a diameter. The size of the 
 globule required to extinguish the flame will afford a rough measure of the relative 
 inflammability of the burning body. The combustibility of different gases may also be 
 approximately measured by the sizes of the masses of heated bodies required to set 
 them on fire. An iron wire ^ of an inch thick at a cherry-red heat will inflame hy- 
 drogen, but not olefiant gas, which, however, is kindled by a wire | of an inch thick 
 at the same degree of heat. A wire ~ of an inch thick must be heated to white- 
 ness to inflame hydrogen, but it will kindle phosphoretted hydrogen at a low red heat. 
 Carbonic oxide takes fire in the air by contact with an iron wire at a dull red heat ; 
 but the fire-damp of mines is not kindled by a wire ^ of an inch thick heated even 
 to whiteness. (Davy.) 
 
 Compression of the air does not appear to facilitate combustion, unless it takes place 
 rapidly, and is consequently attended with considerable evolution of heat. Thenard, 
 however, found that wood does not take fire in oxygen gas under the ordinary pres- 
 sure at temperatures below 350 C., but under a pressure of 2*6 met. combustion 
 begins at 252. On the other hand, phosphorus in oxygen gas or common air exhibits 
 slow combustion at a temperature which is lower in proportion as the gas or air is 
 more rarefied ; and a mixture of oxygen and phosphoretted hydrogen, which, under the 
 ordinary atmospheric pressure, requires a temperature of 116'7 C. to inflame it, does 
 not take fire at 118 when the density is increased to fifteen times its former amount ; 
 but if the mixture, contained in an inclined glass tube standing over mercury, be rarefied 
 by setting the tube upright, combustion takes place at 20. Dobereiner likewise 
 found (J. pr. Chem. i. 114) that a mixture of equal measures of oxygen, hydrogen, and 
 nitrogen gases contained in a detonating tube was always exploded by the electric 
 spark, if the tube were open at the bottom, or merely closed with water ; but not 
 always when the tube was closed by a cork, the compression appearing to offer an 
 obstacle to the continuation of the combustion. 
 
 The combination of oxygen with inflammable gases and vapours is greatly facili- 
 tated by contact with platinum and certain other metals, the effect depending partly 
 on the power possessed by the metal of condensing the gases on its surface or within 
 its pores, if it be in the spongy or finely divided state, partly on a polarised condition 
 of the molecules (see CONTACT-ACTION). When a clean plate or wire of platinum is 
 immersed in a mixture of oxygen (or common air) and a combustible gas, a slow com- 
 bustion takes place at first, by which the temperature of the solid body is raised, 
 and consequently, the process of combustion is not only sustained but actually ac- 
 celerated ; and at length the temperature of the solid body may be so much raised as 
 to give rise to rapid combustion. The larger the surface of the metal, the more 
 powerful is its action. 
 
 It was observed by Sir H. Davy that a mixture of oxygen gas or common air with 
 hydrogen, carbonic oxide, olefiant gas, cyanogen, or vapour of hydrocyanic acid, 
 alcohol, ether, rock-oil, or oil of turpentine, is brought into a state of slow combustion 
 by contact with thin platinum foil or a spiral of platinum wire heated to a tempe- 
 rature short of redness, that the heat thus developed brings the platinum to a state 
 of bright ignition, and that, with certain gases, rapid combustion at length ensues. 
 He likewise found, as had been previously observed by Grotthus, that the mixture of 
 oxygen and hydrogen gases heated not quite to redness in a glass tube, passed in a 
 few minutes into the state of combination and formed water, without sensible evolu- 
 tion of light and heat. Erman showed that the platinum wire requires a temperature 
 of only 50 to 51 C. in order to induce the combination of oxygen and hydrogen. 
 E. Davy found that platinum-black (platinum in a state of division still finer than that 
 of spongy platinum), moistened with alcohol, became incandescent in the air .and 
 induced combustion of the alcohol. Finally, Dobereiner discovered that freshly 
 ignited spongy platinum (as it remains after ignition of ammouio-chloride of plati- 
 num) excites, even in the cold, first the slow, and then, under favourable circum- 
 stances, the rapid combustion of a mixture of hydrogen gas with oxygen or atmo- 
 spheric air. It appears from the experiments of Dobereiner, Pleischl, Dulong, and 
 Thenard, that this property is possessed (though in a less degree, so that in most 
 cases the temperature must be raised, though never to the burning point) by other 
 solid substances, both metallic and non-metallic, e.g. palladium, rhodium, iridium, 
 osmium, gold, silver, cobalt, nickel, charcoal, pumice-stone, porcelain, glass, rock 
 crystal, and fluor-spar. 
 
 These effects may be shown in either of the following ways : 
 
 1. Spongy platinum fastened to the end of a wire is suspended within a glass flask, 
 which is then exhausted of air and filled with the mixture of oxygen and the com- 
 bustible gas. 2. The gaseous mixture is contained in a vessel standing over mercury, 
 
COMBUSTION. 1093 
 
 and the spcngy platinum fastened to a wire is pushed up into it : or a piece of it is 
 simply passed up by itself through the mercury into the gas. The platinum is best 
 prepared for this purpose by forming a mixture of moistened clay and ammonio- 
 chloride of platinum, or of sal-ammoniac and spongy platinum, into balls, and heating 
 them gently : the balls thus prepared may be used several times. 3. The mixture of 
 oxygen or air with the combustible gas is directed on the spongy platinum contained 
 in a glass dish or a funnel. 4. The spongy platinum is attached to a fine platinum 
 wire (for this purpose the platinum wire may be wound into a spiral, or a loose net 
 may be made of it ; and upon this a portion of ammonio-chloride of platinum, made 
 into a thick paste with a small quantity of water, may be fastened, and then ignited) ; 
 u stream of the combustible gas is then to be directed upon it : the gas is thus brought 
 in contact with the platinum after first mixing with the air. 5. Fine platinum wire 
 is wound from three to eight times in a spiral form round a thin glass rod or an iron 
 wire, the turns of the spiral being kept very close together : it is then removed, and 
 inserted by its lower extremity into the end of a glass tube, from which the combus- 
 tible gas issues into the air ; or the lower turns of the spiral are fixed round the wick 
 of a lamp fed with a combustible and volatile liquid, such as alcohol, ether, or a vola- 
 tile oil ; or again, the end of the wire is inserted into the middle of the wick or into a 
 capillary tube into which the liquid rises. This arrangement serves for the lamp 
 without flame or glow-lamp (i. 74). It is usual to set fire to the vapour, and let it 
 burn till the platinum wire becomes red-hot ; then, when the flame is blown out, the 
 wire continues to glow. 6. A triangle of fine platinum foil is cemented by one of its 
 corners into a thin glass rod, which serves for a handle, and held over the aperture (in 
 some cases after being heated) from which the combustible gas issues into the air, 
 or else over a volatile liquid, such as alcohol or ether. The greater the purity of the 
 ammonio-chloride, the more efficient is the spongy platinum prepared from it. As 
 with platinum, so also with the other metals above named. 
 
 Effect of mechanical division. Many finely divided substances are capable of burn- 
 ing at comparatively low temperatures, as shown by the following experiments : 
 When oxide of nickel, cobalt, or iron is reduced by hydrogen gas at a temperature of 
 about 360 C., or not quite amounting to redness, or when oxalate of iron is heated in 
 close vessels not quite to redness, whereby the iron is reduced, the metallic powder thus 
 obtained burns with a glimmering light on being exposed to the air at ordinary tem- 
 peratures. If the heat during the reduction be raised to redness, or if the metal re- 
 duced at a heat below redness be afterwards ignited in hydrogen gas, it will no longer 
 exhibit spontaneous combustibility, possibly, because the metal when thus, strongly 
 heated agglomerates in denser masses : but if a quantity of alumina or glucina be mixed 
 with the metallic oxide, by mixing the solution with that of the salt of alumina or 
 glucina, and precipitating by an alkali, the metal, when reduced by hydrogen, even at 
 a red heat (provided the heat has not been very intense), takes fire on exposure to 
 the air, as readily as that which has been reduced at a lower temperature, possibly, 
 because the interposition of the earths, which are not reduced by the hydrogen, pre- 
 vents the particles of metal from welding together. Copper reduced by hydrogen gas 
 at a very moderate heat was likewise observed on one occasion to become covered, on 
 exposure, with a film of oxide, without however taking fire. Iron reduced by hydrogen 
 gas absorbs several times its volume of carbonic acid gas ; it thereby loses its inflamma- 
 bility, which, however, it recovers by being again heated in hydrogen gas. This pro- 
 perty of spontaneous inflammability may be explained in two different ways : 1. The 
 metal reduced by hydrogen retains a portion of this gas enclosed among its particles ; 
 when exposed to the air, it induces combination between this substance and the 
 oxygen of the air (after the manner of Dobereiner's process), and the great heat 
 evolved in this combination causes the metal to take fire. Against this, however, it 
 may be alleged that iron reduced from the oxalate cannot contain hydrogen gas en- 
 closed amongst its particles (it may, however, contain carbonic oxide) ; and even when 
 the metal is thrown into water, and the water driven off by evaporation, spon- 
 taneous combustion is still produced by contact of air. 2. The metal when exposed 
 to the air absorbs the air mechanically, just as any porous body would do (and pos- 
 sibly it may absorb oxygen with peculiar avidity) ; and the heat developed by this 
 mechanical absorption gives rise to the combustion. If the metal has been previously 
 saturated with carbonic acid gas, of which perhaps it absorbs a larger quantity than 
 of oxygen, it does not become heated by contact with the air (Magnus). Wohler 
 likewise found that intimate mixtures of charcoal and reduced metals often possess 
 the property of taking fire at a red heat. 
 
 The spontaneous combustion of other porous substances, such as charcoal-powder or 
 small coal, and especially of masses of tow, cotton, or rags saturated with oil, takes place 
 in a similar manner. The substance absorbs and condenses the air within its pores ; 
 oxidation then commences immediately and raises the temperature, which again 
 
1094 COMBUSTION. 
 
 accelerates the oxidation ; and thus the process goes on with continually increasing 
 rapidity, till at length the mass bursts into flame. The low conducting power of such 
 a porous mass greatly facilitates the combustion, by preventing the dissipation of the 
 heat generated. Instances are known of olive oil igniting upon sawdust; of greasy 
 rags from butter, heaped together, taking fire within a period of twenty-four hours ; of 
 the spontaneous combustion of tape-measures, which are covered with an oil-varnish, 
 when heaped together ; and even of an oil-skin umbrella put away in a damp state. 
 The presence of moisture greatly promotes the spontaneous ignition of porous materials, 
 such as hay or coal-dust, the water probably supplying oxygen to the combustible 
 matter. (See Graham' s Beport on the cause of the fire in the " Amazon." Chem. Soc. 
 Qu. J. v. 34.) 
 
 II. Nature of Flame. 
 
 The fire which accompanies the process of combustion appears either as Glow or 
 Incandescence, when the burning body does not become gaseous before combustion, or 
 as Flame, when the burning body is previously converted into gas or vapour. In the 
 former case, the heat evolved at the surface of contact of the oxygen and the com- 
 bustible body, charcoal or iron for example, heats the body and causes it to glow with 
 various degrees of brightness, according to the temperature. Feebly glowing coals 
 emit a dull red light (cherry-red heat or dull red heat) ; when more strongly heated, 
 they emit a yellowish-red light (bright or full red heat) : at still higher temperatures, 
 a yellow light (dull or commencing white heat) ; then a yellowish, then a greenish, and 
 lastly a bluish-white, intensely dazzling light (bright, full, or dazzling white heat). 
 
 When the combustible body is in the gaseous form, either originally or in conse- 
 quence of the heat required to set it on fire, the mixture of this gas with the oxygen 
 and the products of the combustion constitutes flame, which is, in fact, gaseous matter 
 heated to incandescence. If the combustible gas or vapour, and the oxygen or air are 
 uniformly mixed before ignition, the combustion takes the form of an explosion, com- 
 bination taking place at once throughout the whole mass of gaseous matter, which conse- 
 quently appears equally luminous throughout. A similar effect takes place when a com- 
 bustible substance, such as sulphur or charcoal, is intimately mixed with a nitrate, 
 chlorate, or other solid substance which readily gives up oxygen : if the temperature of 
 such a mixture be raised to the burning point at one spot by friction, percussion, or 
 the contact of a hot body, the ignition of the first few particles raises the temperature 
 of the next, and then the action is propagated in an inappreciably short space of time 
 throughout the whole mass, producing a sudden and violent evolution of gas, occupying 
 many thousand times the volume of the original solid mixture. The noise attending 
 the explosion arises from the violent concussion of the surrounding air produced by 
 the sudden expansion of the burning gases. 
 
 But when the combustible gas or vapour issues from an orifice or a wick into the 
 air, or into an atmosphere of oxygen, the combustion takes place gradually at the 
 surface of contact of the two gases, and a flame is produced, consisting of an inner 
 dark and less heated space filled with the combustible gas, and a glowing envelope 
 marking the boundary at which the combustible gas and the oxygen come in contact 
 and unite. That such is really the structure of flame may be shown by placing a 
 piece of phosphorus on the wick of a burning spirit lamp, the phosphorus not taking 
 fire till it is pushed outwards. If a piece of phosphorus be placed on a wooden 
 support in the middle of a basin filled with alcohol, and the alcohol be set on fire, the 
 phosphorus melts, but does not take fire till the alcohol is burnt away or extinguished, 
 or till the flame is blown on one side, or air directed upon the phosphorus by means 
 of the blowpipe. In a similar manner, a lighted candle will go out when placed in 
 the midst of an alcohol flame. 
 
 The brightness or illuminating power of flame depends, not only on the degree of 
 heat, but likewise on the presence or absence of solid particles which may act as 
 radiant points. A flame containing no such particles emits but a feeble light, even if 
 its temperature is the highest possible the flame of hydrogen gas, for example. But 
 in flames which do contain solid particles, the brightness increases with the tempera- 
 ture to which these particles are raised. Solid particles in a flame sometimes arise 
 from the combination of the combustible body with oxygen, e. g. phosphoric acid or 
 oxide of zinc in the combustion of phosphorus or zinc ; sometimes, when the burning 
 body is an organic hydrocarbon in the gaseous state, they consist of particles of 
 carbon in the form of soot, separated in the interior of the flame by the heat of the 
 burning envelope. A dull flame becomes brighter by the introduction of a solid body 
 in a finely divided state. 
 
 The following substances give a dull flame : hydrogen gas, carbonic oxide gas, sul- 
 
COMBUSTION. 1095 
 
 phur, selenium, arsenic, alcohol and likewise coal-gas when it is mixed with a 
 sufficient quantity of air to cause it to burn without deposition of soot : phosphorus 
 also burns with a dull flame in chlorine gas, because the chloride of phosphorus, which 
 is the product of the combustion, remains in the gaseous state (H. Davy). When a 
 spiral of platinum wire or a piece of asbestos is held in either of these flames, or some 
 powdered oxide of zinc thrown into it, the solid matter immediately becomes white, 
 and emits a vivid light (H. Davy). Paper soaked in solution of chloride of calcium, 
 and burnt in the flame of a spirit lamp, leaves a white network of ashes, which, when 
 held in the feeblest alcohol flame, emits a brilliant light. (Talbot, Phil. Mag. [31 iii. 
 114.) 
 
 If alcohol vapour be projected from one set of tubes, and oxygen gas from another 
 set, upon a ball of quicklime, having a stem by which it is fastened to a wire, the 
 alcohol burning in the oxygen gas heats the ball to the most dazzling whiteness ; so 
 that the light, when reflected by a concave mirror placed behind it, is plainly visible 
 at the distance of 68 miles. Zirconia gives a light somewhat less powerful than that 
 of lime; that produced by magnesia is only half as strong. (Drummond, Ed. J. 
 of Sc. 5, 319.) By the oxy-hydrogen blowpipe (i. 613) lime is rendered much more 
 brightly luminous than by alcohol and oxygen gas. Supposing the intensity of light 
 of a wax candle = 1, that emitted by a cylinder of lime whose circumference is one- 
 fifth of that of the flame of the candle, is equal to 153 when it is ignited by the oxy- 
 hydrogen flame; to 76, in the flame of ether and oxygen; to 69, in that of alcohol 
 and oxygen; and to 19, in that of coal-gas and oxygen. Unburnt chalk, white clay, 
 and magnesia, give much less light than burnt chalk. 
 
 A bright flame is produced by the following bodies : 
 
 1. Those which in combination with oxygen form a solid compound : phosphorus, 
 potassium, antimony, bismuth, zinc, and most other metals. (Davy.) 
 
 2. Compounds containing carbon, from which a portion of the carbon is separated 
 in the form of soot, by the heat produced at the part where the combustion actually tak^s 
 place, the separated carbon being first brought to a state of vivid incandescence, and 
 subsequently burnt when it comes in contact with oxygen. This is the case with 
 marsh-gas, olefiant gas, ether, volatile oils, fats, resins, &c. (H, Davy). The flame of 
 alcohol may likewise be rendered bright by the presence of any substance which 
 causes the carbon to separate from it. Thus, chlorine gas mixed with the flame of 
 alcohol increases its luminosity, because, by combining with the hydrogen, it causes a 
 deposition of solid carbon. Vapour of dioxide of osmium likewise gives luminosity 
 to the flame of alcohol, by giving up osmium and separating carbon from the alcohol. 
 To produce this effect, a piece of osmium is laid on the edge of a piece of platinum- 
 foil, and the foil held over the alcohol flame, so that the osmium may burn, and the 
 vapours of the oxide may mix with the vapour of alcohol (Berzelius). The flame 
 of hydrogen or marsh -gas may be rendered bright by passing the gas through coal-tar 
 naphtha, rock-oil, or some other volatile hydrocarbon, the vapour of which then mixes 
 with the gas and brightens the flame by the separation of its carbon. 
 
 On the contrary, by mixing a jet of carbonaceous gas or vapour with oxygen, as in 
 Bunsen's gas-burner, in which air is admitted just above the point where the stream 
 of gas enters the burner, so that the gas and air become well mixed before they reach 
 the orifice, a complete combustion of the carbon is obtained, and only gaseous products 
 are formed, the result being a very hot smokeless flame of feeble luminosity. A 
 similar flame is obtained by laying a sheet of wire-gauze on the top of the chimney 
 of an Argand gas-burner, and setting fire to the gas above the gauze. The gas then 
 becomes well mixed with air in passing up the chimney, and the carbon is completely 
 burned as before. 
 
 The more slowly a carbonaceous substance is burned, the greater is the quantity of 
 carbon separated from it ; the brightness of the flame is, however, diminished in the 
 same proportion, because the particles of carbon are less strongly heated. On the 
 contrary, the quicker the combustion, the smaller is the quantity of carbon separated ; 
 but the temperature to which it is raised is so much the higher, and consequently it 
 emits a brighter light. 
 
 The flame of highly carbonised substances, such as a wax or tallow candle, consists 
 of four parts, as represented in fig. 129. a, a dark inner cone, surrounding the wick, 
 and consisting of the combustible gas and vapour issuing therefrom, mixed with atmo- 
 spheric nitrogen and the products of combustion, viz. water and the oxides of carbon ; 
 
 b, a light blue zone at the bottom of the flame, and reaching a little way up the inner 
 cone. In this part, the combustible matter of the inner cone comes in contact with 
 the oxygen of the air not yet rarefied by the heat, and is completely burned just as in 
 the inner blowpipe-flame (i. 613), producing a light of the same bright blue colour. 
 
 c, a highly luminous cone surrounding the dark inner cone. In this part, the supply of 
 oxygen is not sufficient, excepting at the outer surface, for the complete combustion 
 
1096 
 
 COMBUSTION. 
 
 of the carbon, which is therefore separated in minute solid particles, and these being 
 strongly heated by the combustion, become highly incandescent : if a cold 
 Fig. 129. body be introduced into the flame, these particles of carbon are deposited 
 as soot, d, the mantle, a feebly luminous, yellowish cone surrounding the 
 entire flame, excepting just at the bottom, and consisting of atmospheric 
 air heated to incandescence, and mixed with the final products of the 
 combustion. This part of the flame is often confounded with the blue 
 zone, from which, however, it is really distinct. The best mode of ob- 
 serving it is to cut out a piece of cardboard of nearly the shape of the 
 flame, and hold it at such a distance from the eye as just to hide the lumi- 
 nous cone. 
 
 The flame of an Argand lamp, which is supplied with air within as well 
 as without, may be compared to the flame of an ordinary lamp or candle 
 flattened out, and then bent into a cylinder. It contains the same parts 
 as the conical flame, but from the form of the wick, the dark zone is ne- 
 cessarily very thin. 
 
 The composition of the flame of wax and tallow burning from a wick 
 has been accurately investigated by Hilgard (Ann. Ch. Pharm. xcii. 
 129; Jahresb. f. Chem. 1854, p. 287). The lamp used in the experi- 
 ments consisted of a shallow cylinder containing the fuel, and having in 
 its axis a glass tube, over the upper end of which the cylindrical wick was 
 drawn. Through this tube, which was capable of sliding up and down, 
 a narrower tube connected at its lower end with an aspirator passed 
 upwards into the flame. This narrow tube was attached to the outer tube 
 by means of a caoutchouc connecter, in such a manner that no air could 
 pass through the wide tube into the flame. By this arrangement, the gases could be 
 collected at any required height in the flame ; they then passed through a series of 
 condensers, and finally into a glass tube in which they were sealed up for examination. 
 In the following table, the composition of the gases at different heights (in milli- 
 metres) above ( + ) and below ( - ) the edge of the wick is given in percentages by 
 volume; the symbol C 2 H 4 includes ethylene and the hydrocarbons polymeric with it. 
 X denotes the weight of liquid and solid matter condensed from a litre of the flame- 
 gas. 
 
 Composition of Wax and Tallow flames. 
 
 Beef-tallow Flame. 
 
 Wax Flame. 
 
 i 
 
 X. 
 
 N. 
 
 CO*. 
 
 CO. 
 
 C*H<. 
 
 CH". 
 
 H. 
 
 I 
 
 X. 
 
 N. 
 
 CO2. 
 
 CO. 
 
 C'H<. 
 
 CH<. 
 
 H. 
 
 DC 
 
 
 
 
 
 
 
 
 B 
 
 
 
 
 
 
 
 
 +9 
 
 0-12 
 
 75-92 
 
 14-46 
 
 5-65 
 
 1-52 
 
 1-15 
 
 1-30 
 
 + 10 
 
 0-12 
 
 76-62 
 
 11-70 
 
 5-16 
 
 3-70 
 
 0-85 
 
 1-97 
 
 
 
 
 
 
 
 
 
 8 
 
 0-15 
 
 73-96 
 
 11-46 
 
 5-73 
 
 5-16 
 
 088 
 
 2-81 
 
 r, 
 
 0-11 
 
 72-28 
 
 10-90 
 
 6-25 
 
 6-04 
 
 2-68 
 
 1*85 
 
 6 
 
 0-18 
 
 70-34 
 
 10-53 
 
 5-50 
 
 9-21 
 
 170 
 
 2-71 
 
 4 
 
 13 
 
 64-40 
 
 10-24 
 
 6-68 
 
 13-10 
 
 2-70 
 
 2-88 
 
 4 
 
 0-32 
 
 64-15 
 
 9-99 
 
 5-86 
 
 14-29 
 
 2-93 
 
 2-78 
 
 2 
 
 0-38 
 
 59-01 
 
 10-14 
 
 7-22 
 
 17-12 
 
 3-78 
 
 2-73 
 
 2 
 
 0-48 
 
 64-09 
 
 1007 
 
 5-62 
 
 14-89 
 
 2-fi2 
 
 2-73 
 
 n 
 
 0-70 
 
 63-57 
 
 7-13 
 
 4-60 
 
 18-77 
 
 5-2 ' 
 
 0-73 
 
 
 
 1 00 
 
 65-36 
 
 10-00 
 
 5-42 
 
 14-23 
 
 2-31 
 
 2-69 
 
 -3 
 
 1-49 
 
 61-72 
 
 11-73 
 
 6-27 
 
 15-13 
 
 4-00 
 
 0-15 
 
 - 3 
 
 1-57 
 
 63-61 
 
 1078 
 
 5-70 
 
 14-29 
 
 3-08 
 
 2-54 
 
 Without the Nitrogen : 
 
 ,Q 
 
 
 
 60 06 
 
 23*46 
 
 6' 29 
 
 479 
 
 5*40 
 
 + 10 
 
 
 
 50-01 
 
 22'08 
 
 15-83 
 
 3'64 
 
 8-43 
 
 
 * * 
 
 * ' 
 
 
 
 
 
 
 8 
 
 
 
 44-00 
 
 19-80 
 
 19-80 
 
 338 
 
 10-81 
 
 C> 
 
 
 
 39-31 
 
 22-54 
 
 21-79 
 
 968 
 
 fi-68 
 
 6 
 
 
 
 35-57 
 
 3098 
 
 HO -98 
 
 575 
 
 9-16 
 
 4 
 
 
 
 28-78 
 
 18-75 
 
 36-81 
 
 8-08 
 
 7-58 
 
 4 
 
 
 
 27-87 
 
 39-H? 
 
 39-87 
 
 8-18 
 
 7-75 
 
 2 
 
 
 
 24-73 
 
 17-62 
 
 41-78 
 
 9-21 
 
 6-6<i 
 
 2 
 
 
 
 28-04 
 
 41-43 
 
 41-43 
 
 729 
 
 7-60 
 
 
 
 
 
 19-5* 
 
 12-63 
 
 51-51 
 
 1428 
 
 2-00 
 
 
 
 
 
 28 86 
 
 41-07 
 
 41-07 
 
 6-67 
 
 7-75 
 
 -3 
 
 
 
 30-65 
 
 16-38 
 
 39-53 
 
 10-44 
 
 3-07 
 
 - 3 
 
 
 
 29-62 
 
 39-27 
 
 39-27 
 
 8-48 
 
 6-97 
 
 The large quantity of nitrogen in the interior of the flame arose from the circum- 
 stance, that the air entered the flame in a nearly horizontal direction, especially at the 
 lower part. The proportion of nitrogen is a minimum at 2mm. above the edge of the 
 wick, chiefly because the greater heat and increasing amount of decomposition in this 
 part of the flame produce a larger amount of permanent gases. The quantity of 
 carbonic anhydride is nearly inversely proportional to that of the hydrocarbons, C n H 2n . 
 When the nitrogen is deducted, the sums of the amounts of carbonic anhydride, ethy- 
 lene, &c., and carbonic oxide are nearly constant. The total quantity of these three 
 gases appears to alter but slightly from the bottom of the flame to a height of 7mm. or 
 8mm ; at a greater height, it appears to increase, in consequence of the excess of the 
 products of oxidation. 
 
 The inner cone of the flame contains the uuburnt gases issuing from the wick, 
 
COMBUSTION. 
 
 1097 
 
 Fig. 130. 
 
 mixed with atmospheric nitrogen and carbonic oxide, carbonic acid, and water, pro- 
 duced by the combustion going on in the outer cone, but no free oxygen, that gas being 
 completely converted into the products just mentioned in passing through the outer 
 cone. The composition of the gases at different heights of the flame is determined 
 by the natural action of the combustible gases in the inner cone and the oxidised 
 products proceeding from the outer part. 
 
 The luminous envelope surrounding the inner cone varies In composition from with- 
 out inwards, the outer portion containing a considerable quantity of free oxygen 
 which gradually diminishes as it penetrates inwards. The thickness of the luminous 
 envelope increases towards the upper part of the flame, because this portion contains 
 the oxidised products ascending from below, in addition to those directly formed 
 there, so that the proportion of combustible gases in the upper part of the flame is less, 
 the combustion is slower, and the oxygen of the air can penetrate to a greater depth ; 
 hence the luminous envelope diminishes in brightness and increases in thickness from 
 below upwards, and near the apex it presents the appearance of a solid cone. The 
 reducing part of the flame is at the surface of contact of the inner cone and the luminous 
 envelope. 
 
 The flames of combustible bodies which do not undergo the decompositions above 
 described, differ considerably in composition from those of wax or tallow. The luminous 
 cone is often absent, more rarely the mantle : the inner cone is of course always pre- 
 sent, and the blue zone is almost always represented by 
 the part where the still undiluted combustible gas comes 
 in contact, at a comparatively low temperature, with air 
 containing its full amount of oxygen. The flame of car- 
 bonic oxide exhibits a distinct dark cone (consisting of 
 unburnt gas), a dark blue zone, and a yellowish-red mantle 
 not sharply defined from the surrounding air. The flame 
 of sulphur has a blue zone at the bottom and a violet- 
 reddish mantle, the colour with which sulphur-vapour 
 burns when previously strongly heated. In the alcohol- 
 flame (fig. 130) the inner cone a is very large, in conse- 
 quence of the volatility of the combustible substance : the 
 luminous cone b is small, because there is but little carbon 
 separated ; and the mantle d appears very much developed, 
 because the eye is not dazzled by a bright luminous cone. 
 
 The composition of the flame of coal-gas has been ex- 
 amined by Landolt (Fogg. Ann. xcix. 389), by a method 
 similar to that above described for the wax and tallow 
 flames. The gas, properly purified from carbonic acid, 
 oxygen, and aqueous vapour, was passed, under pressure 
 of a column of water, 17 Paris lines high, into a brass box, 
 having at the top a circular aperture 7mm. wide, and a tube of nearly the same diameter 
 passing tightly through the? bottom, and terminating on a level with the circular 
 opening, so that the gas was made to issue through the narrow ring-shaped slit thus 
 formed. A tube connected with an aspirator passed up through the brass tube into 
 the flame, as in Hilgard's experiments. The flame was protected from draughts of 
 air by a glass cylinder suspended over it and reaching to within 20mm. of the burner ; 
 it was from 95 to 100mm. high when burning freely, and from 85 to 95mm. while gas 
 was being drawn out of it. The following table gives the composition of the purified 
 coal-gas (L) introduced into the burner, and that of the flame-gas, at various heights, 
 D mm., above the ring-shaped aperture, in percentages by volume (F). 
 
 Composition of Coal-gas flame. 
 
 D . . 
 
 Omm. 
 
 10mm. 
 
 20mm* 
 
 30mm. 
 
 40mm. 
 
 60mm. 
 
 
 L 
 
 F 
 
 L 
 
 F 
 
 L 
 
 F 
 
 L 
 
 F 
 
 L 
 
 F 
 
 L 
 
 F 
 
 Hydrogen 
 
 39-30 
 
 20-34 
 
 41-04 
 
 12-45 
 
 44-00 
 
 2-23 
 
 44-00 
 
 499 
 
 41-37 
 
 3-43 
 
 41-37 
 
 2-59 
 
 Marsh-gas 
 
 40-56 
 
 30-31 
 
 4071 
 
 25-14 
 
 38-40 
 
 ll-:>2 
 
 3840 
 
 6-92 
 
 3830 
 
 2-8-2 
 
 38-30 
 
 07!) 
 
 Carbonic oxide 
 
 4-95 
 
 6-59 
 
 7-64 
 
 11-71 
 
 5-73 
 
 5-71 
 
 5-73 
 
 4-68 
 
 5-56 
 
 5-26 
 
 5'56 
 
 5-45 
 
 Ethylene . 
 
 4-04 
 
 380 
 
 5MO 
 
 3-59 
 
 4-13 
 
 1-8H 
 
 4-13 
 
 1-55 
 
 5-00 
 
 0-90 
 
 5-00 
 
 0-Gf 1 
 
 Tetrvlene 
 
 3-15 
 
 275 
 
 2-18 
 
 265 
 
 3-14 
 
 1-34 
 
 314 
 
 I'OO 
 
 4-34 
 
 077 
 
 434 
 
 0-5H 
 
 Oxygen . 
 
 __ 
 
 0-59 
 
 
 
 0-65 
 
 
 
 0-19 
 
 
 
 
 
 
 
 Nitrogen . 
 
 800 
 
 26-40 
 
 275 
 
 32-20 
 
 4-23 
 
 5725 
 
 4-23 
 
 59-18 
 
 543 
 
 4 01 
 
 5-43 
 
 6K-.V 
 
 Carbonic acid 
 
 _ _ 
 
 1-74 
 
 0-58 
 
 1-95 
 
 0-37 
 
 4'11 
 
 0-37 
 
 4-81 
 
 
 5-6'J 
 
 
 7-01 
 
 Water 
 
 
 
 748 
 
 
 
 9-66 
 
 
 15-79 
 
 
 1G-87 
 
 
 
 17-19 
 
 
 
 16-3'J 
 
T098 
 
 COMBUSTION. 
 
 From these results, Landolt has calculated the proportions of coal-gas and air which 
 by their mutual action form the several parts of the flume-gas. The results are some- 
 what discordant, according as the carbon, hydrogen, or nitrogen is taken as the basis 
 of the calculation ; but the most probable results are given in the following table, in 
 which A denotes the volumes of atmospheric air which have mixed with 100 vols. coal- 
 gas to produce the flame-gas at the several heights, D, indicated in the first line. 
 100 + A = M volumes of this unburnt gaseous mixture yield, after combustion, V 
 volumes of flame-gas. The composition of the M volumes of unburnt gaseous mixture 
 and of the V volumes of flame-gas produced by their combustion are given in the lower 
 part of the table. 
 
 Composition of Coal-gas flame. 
 
 D . . . 
 
 Omm. 
 
 10mm. 
 
 20mm. 
 
 30mm. 
 
 40mm. 
 
 50mm. 
 
 A ... 
 
 27-08 
 
 45-43 
 
 172-76 
 
 227-73 
 
 335-30 
 
 881-66 
 
 M . . . 
 
 127-08 
 
 145-43 
 
 272-76 
 
 327-73 
 
 435-30 
 
 481-66 
 
 V ... 
 
 111-41 
 
 120-09 
 
 245-96 
 
 311-37 
 
 422-59 
 
 401-23 
 
 
 M 
 
 V 
 
 M 
 
 V 
 
 M 
 
 V 
 
 M 
 
 V 
 
 M 
 
 V 
 
 M 
 
 V 
 
 Hydrogen 
 
 39-30' 
 
 22-66 
 
 41-04 
 
 14-95 
 
 44-00 
 
 5-49 
 
 44-00 
 
 1 s-54 
 
 41-37 
 
 14-50 
 
 41-37 
 
 1 1 -95 
 
 Marsh-gas 
 
 40-56 
 
 33-77 
 
 40-71 
 
 30-20 
 
 38-40 
 
 28-34 
 
 38-40 
 
 21-55 
 
 38-80 
 
 11-92 
 
 38-30 
 
 304 
 
 Carbonic oxide 
 
 4-95 
 
 7-34 
 
 7'64 
 
 14-07 
 
 5-73 
 
 14-05 
 
 5-73 
 
 14-58 
 
 5-56 
 
 22-24 
 
 5-56 
 
 25-14 
 
 Kthvlene 
 
 4-04 
 
 4-2:? 
 
 5-10 
 
 431 
 
 4-13 
 
 4-58 
 
 4-13 
 
 4 83 
 
 5-iO 
 
 380 
 
 5-00 
 
 277 
 
 Tetrylene 
 
 3-15 
 
 3-06 
 
 2- IS 
 
 3-18 
 
 3-14 
 
 3-29 
 
 3-14 
 
 3-11 
 
 4-34 
 
 3-25 
 
 4-34 
 
 2-68 
 
 Oxygen 
 
 .5-07 
 
 0'6'i 
 
 9-52 
 
 0-78 
 
 36-21 
 
 0-47 
 
 47-73 
 
 
 
 70 '28 
 
 
 
 79-99 
 
 
 
 Nitrogen 
 
 29-41 
 
 29-41 
 
 3866 
 
 3H-66 
 
 14078 
 
 140-78 
 
 184 -23 
 
 I 84-23 
 
 270-45 
 
 270-45 
 
 307-10 
 
 307-10 
 
 "arbonic acid 
 
 
 
 1-94 
 
 
 
 2-:i4 
 
 0-37 
 
 10-11 
 
 0-37 
 
 14-98 
 
 
 2376 
 
 
 
 32-34 
 
 Water 
 
 
 
 8-34 
 
 
 
 11-60 
 
 
 
 38-85 
 
 
 
 52-55 
 
 
 
 72.G7 
 
 
 
 75-61 
 
 
 127-08 
 
 111-41 
 
 145-43 
 
 L-.O-O; 
 
 27-2-76 
 
 245-96 
 
 327-73 
 
 311-37 
 
 435-30 
 
 422-59 
 
 481-66 
 
 461-2:' 
 
 The sudden increase in the quantity of air mixing with the combustible gas between 
 the heights of 10 and 20mm., is attributed by Landolt to the effect of the glass cylinder. 
 The proportion of carbonic acid does not increase towards the upper part of the flame 
 so rapidly as might be expected, probably on account of the reduction of that gas to 
 carbonic oxide by the the ignited carbon in the flame ; hence also the sudden increase in 
 the proportion of carbonic oxide between the heights of 30 and 40mm. The quantities of 
 the several combustible gases in the flame diminish from below upwards, at rates propor- 
 tional to their combustibility. From to 20mm. the decrease of the hydrogen is the most 
 rapid ; the increase in the proportion of this gas in the flame above the height of 20mm. 
 is probably due to the reducing action of the ignited carbon in the aqueous vapour. 
 The marsh-gas diminishes more slowly, and the heavy hydrocarbons still more slowly, 
 the latter indeed remaining nearly unaltered in the flame up to 40mm., and burning only 
 in the higher part. 
 
 The brightest light was found to be given out by the part of the flame a little above 
 the top of the dark cone. In a gas-flame 100mm. high, in which the dark cone reached 
 to about 65mm., the highest part was at 70mm., and supposing the brightness of this 
 part = 100, that of the other parts of the flame was found to be as follows : 
 
 mm. min< mm. mm. mm. mm* 
 
 Height above burner . . 80 70 60 50 40 30 
 
 Brightness at the edge . . 66 100 77 47 20 4 
 
 Brightness in the middle .66 100 59 24 5 
 
 The size of a flame is greater in proportion as a larger quantity of oxygen is re- 
 quired to consume a given volume of the rising combustible gas, and also as the sur- 
 rounding oxygen is mixed or combined to a greater extent with foreign gases ; for, in 
 that case, the combustible gas must present a larger circumference, and a greater number 
 of points of contact to the oxygen, in order that the latter may be consumed as fast as 
 it is supplied. 
 
 When different combustible gases aie made to flow from a jet, in streams of given 
 strength, into oxygen gas and mixtures containing it, the following effects are observed : 
 Hydrogen gas gives a much smaller flame than olefiant gas (1 volume of hydrogen re- 
 quires half a volume of oxygen, and 1 volume of olefiant gas requires 3 volumes of oxygen 
 to burn it). Hydrogen gas mixed with nitrogen gives a still smaller flame than pure 
 hydrogen. The flame of hydrogen gas in oxygen is smaller than that of the same gas 
 in air ; but there is this anomaly observed, that hydrogen gives a smaller flame in air 
 
COMBUSTION. 1099 
 
 than it does in chlorine OP nitrous oxide gas, although one volume of hydrogen gas 
 requires 2'4 volumes of air and only 1 volume of chlorine or"of nitrous oxide gas. This 
 peculiarity is probably due to the different degrees of diffusibility of the gases through 
 each other. 
 
 The colour of the flame depends partly on its temperature, partly on the nature of 
 the substances contained in it. 
 
 Cold carbonic oxide gas gives a blue flame in burning ; but if it has previously been 
 heated, it gives a yellowish red flame. Hydrogen and other gases, which in burning 
 evolve more heat than is evolved by carbonic oxide, exhibit a yellowish red flame even 
 when set on fire in the cold. But when hydrogen gas issues from a fine jet (as in 
 Marsh's apparatus) against a porcelain slab held close in front of it, a pale green flame 
 is produced, possibly in consequence of the cooling action of the porcelain. The blue 
 flame at the lower part of the flame of a candle likewise indicates a comparatively low 
 temperature. It is remarkable that in the glowing combustion of solid bodies the colours 
 exhibit exactly the opposite relation (p. 1094). 
 
 The addition of boric acid, or of a metallic chloride and oil of vitriol, to alcohol, 
 gives the flame a green colour or, when it is more strongly heated, it turns yellow. 
 Chloride of strontium or chloride of calcium colours the flame of alcohol red ; chloride 
 of barium, or common salt, colours it yellow ; protochloride of copper gives it a bright 
 red colour, with green and blue edges. Copper covered with oxide or sulphide (but 
 not clean copper), held in the flame of alcohol, colours it green. The flames of other 
 burning bodies undergo similar alterations. Chloride of strontium reddens the flame 
 of hydrogen, marsh-gas, and olefiant gas, as also that of a candle but only so long as 
 the salt itself remains moist ; on the flame of sulphur it has no effect. In all these cases, 
 a portion of the added substance undoubtedly volatilises : but whether it volatilises un- 
 decomposed, so that the colour of the flame is altered merely by the presence of boracic 
 acid, chloride of strontium, chloride of copper, &c., or whether decomposition takes 
 place, so that boron, strontium, calcium, barium, or copper is introduced into the flame 
 in the reduced state, is there burnt, and thereby produces a different colour is a ques- 
 tion not yet decided. Davy suggested the latter explanation. 
 
 Respecting the prismatic spectra produced by flames in which various salts, &c. are 
 ignited, see ANALYSIS (i. 214), also LIGHT. 
 
 In ordinary flames, the combustible gas occupies the interior, and is surrounded by 
 atmospheric air or oxygen gas. But the combustion may likewise be sustained by 
 directing a stream of oxygen gas, air, &c., into a vessel filled with the combustible gas. 
 The interior dark part of the flame then consists of oxygen gas ; and this gas seems, 
 as it were, to burn in the combustible gas. In this manner, oxygen gas (and also 
 chlorine) may be made to burn in hydrogen ; likewise oxygen gas, common air, vapour of 
 pernitric oxide (or chlorine gas, with large deposition of sootj in olefiant gas. To pro- 
 duce this effect, a stoppered bell-jar standing over water is filled with olefiant gas, 
 the stopper removed, the gas set on fire, and the oxygen tube, which is fitted into 
 a cork, plunged into the olefiant gas, the cork serving to close the aperture. Or a 
 quantity of chlorate of potassium, contained in a small basin suspended from the cork, 
 may be heated till it evolves oxygen gas, and then plunged into the olefiant gas pre- 
 viously set on fire at the mouth of the jar: the combustion then goes on, producing a 
 beautiful light, the colour of which may be variously modified by the addition of nitrate 
 of sodium, strontium, or copper (Kemp, J. Pharm. xx. 413; also J. pr. Chem. iii. 44). 
 
 The flame of oxygen in hydrogen gas is green, even when both gases are quite pure : 
 that of oxygen in marsh-gas is yellow. The first-mentioned flame is much larger than, 
 the other, because a measure of oxygen gas requires two measures of hydrogen, and only 
 half a measure of marsh-gas (Hess, Pogg. Ann. xliv. 336 ; also J. pr. Chem. xiii. 516). 
 
 The flame is smaller when oxygen or nitrous oxide gas, or vapour of pernitric 
 oxide, or chlorine gas is made to pass into hydrogen gas, than in the contrary case ; 
 according to what was said on p. 1098, the contrary might, have been expected. A 
 much smaller flame is produced when oxygen passes into olefiant gas than when it passes 
 into hydrogen. With olefiant gas, the flame is dark within ; then follows a brilliant 
 envelope, hot enough to melt platinum ; then, towards the outside, a dark yellow flame, 
 lengthening above and containing soot, the greater part of which remains unburnt. 
 When oxygen gas is blown into boiling sulphur, a yellow flame is produced, dark within, 
 red on the outside and at the apex : air gives a smaller flame than oxygen, dark within, 
 blue without, and red a* the apex (Wai die, PhiL Mag. [3] xiii. 86). 
 
 The Blow-pipe flame is of the same character as those just mentioned, inasmuch as 
 the air is blown into the middle of the ascending combustible vapour. The strongest 
 heat exists at that part of the flame where the dark cone of injected air terminates in 
 a bluish vertex, and the burning envelope which surrounds it concentrates itself upon 
 a single point (i. 611). 
 
1100 COMBUSTION. 
 
 IIL Causes which modify and extinguish Combustion. 
 
 When the slow or rapid combination of a body with oxygen has once been set up by 
 elevation of temperature, the continuance of this combination, after the supply of heat 
 from without has been withdrawn, depends in general on the following condition : 
 Whether the quantity of heat, which the body in combining with oxygen evolves in a 
 given time, is equal to that which, in the same time, is carried away by surrounding 
 bodies ; and consequently, whether the body remains at the temperature necessary for 
 combustion; and in particular: 1. On the difference between the temperature at 
 which the body will combine with oxygen, rapidly or slowly, and the external tem- 
 perature; 2. On the quantity of heat which it evolves in burning ; 3. On the rarefaction 
 or condensation of the oxygen gas ; 4. On the greater or smaller admixture of foreign 
 gaseous bodies not contributing towards the combustion ; 5. On the presence of liquid 
 or solid heat-conducting bodies. 
 
 1. Iron and diamond require a white heat to make them burn rapidly : hence, when 
 they are heated in the air till they begin to burn, the combustion ceases as soon as the 
 
 1 access of heat from without is discontinued, whereas sulphur, and other easily inflam- 
 mable bodies, continue to burn. 
 
 2. Carbonic oxide gas, which is as easily inflammable as hydrogen, does not exhibit 
 rapid combustion after it has been rarefied to about one-fourth of its ordinary density, 
 because it evolves less heat during combustion. (H. Davy.) 
 
 3. A certain degree of rarefaction prevents the continuance of combustion ; because 
 combination, and therefore, also, development of heat, is retarded by it. Detonating 
 gas (a mixture of two measures of hydrogen gas and one of oxygen), when rarefied 
 to i of its ordinary density, no longer explodes by the electric spark (H. Davy). 
 Hydrogen gas, mixed with air in the right proportion, will not take fire under an 
 external pressure of five inches (Grot thus s). Hydrogen gas issuing from a jet into 
 the air exhibits rapid combustion under a fourfold rarefaction of the air, burning even 
 with a larger flame than before, but is extinguished when the density is reduced to 
 between j and | of its ordinary amount. 
 
 The burning vapour of alcohol, ether, or wax, is extinguished, under these circum- 
 stances, by a five or sixfold rarefaction ; sulphuretted hydrogen by a sevenfold rare- 
 faction of the air. Sulphur continues to exhibit rapid combustion, even when the air 
 is rarefied fifteen times ; phosphorus, when the density is reduced to ^ ; while the 
 easily inflammable variety of phosphoretted hydrogen gas produces a flashing light, 
 even in the best vacuum that can be made with the air-pump. Vapour of ether, in 
 air rarefied thirty times, still produces a feeble flame on the introduction of a red-hot 
 iron. Slow combustion on the surface of platinum is exhibited by marsh-gas, down 
 to a fourfold rarefaction of the air ; by carbonic oxide, to sixfold ; by vapour of alcohol, 
 ether, or wax, to eightfold ; by olefiant gas, to ten or elevenfold ; by hydrogen gas, to 
 thirteenfold ; and by vapour of sulphur, down to twentyfold rarefaction of the air. 
 By elevation of temperature, the limits of inflammability are still further extended ; 
 o that detonating gas rarefied eighteen times, and heated to redness, exhibits a light 
 as if from combustion, on the passage of an electric spark. (H. Davy.) 
 
 Within certain limits, however, the rate of combustion is independent of the density 
 of the surrounding atmosphere. Frank land found thata stearin candle burned away 
 at the same rate on the summit of Mont Blanc and in the valley of Chamounix. The 
 brightness of the flame is, however, greatly diminished by rarefaction of the air. A coal- 
 gas flame, burning in artificially rarefied atmospheres, exhibited an average decrease 
 of illuminating power amounting to about 5'1 per cent, for each diminution of 1 inch 
 of mercurial pressure. (Proc. Eoy. Soc. xi. 137.) See FLAME. 
 
 4. Foreign gaseous bodies, which contribute nothing to combustion, absorb a portion 
 of the heat generated by the combination, and reduce the temperature below the 
 burning point, the rapidity of their action being proportional to their quantity, mobi- 
 lity, -and capacity for heat. Not only do bodies in general burn more rapidly in 
 oxygen gas than in atmospheric air, which contains only one volume of oxygen to four 
 of nitrogen ; but iron and diamond, which, when once set on fire, continue to burn in 
 oxygen gas, are immediately extinguished in atmospheric air. In air four or five 
 times compressed which, therefore, contains one volume of oxygen gas candles, 
 hydrogen gas, sulphur, charcoal, and iron, do not, in consequence of the abstraction of 
 heat by the nitrogen, burn more rapidly than they would in uncompressed air, to 
 which of a volume of oxygen had been added. One volume .of detonating gas loses 
 its power of taking fire by the electric spark, if there be added to it | a volume of 
 olefiant gas, of a volume of fluoride of silicium, 1 volume of marsh-gas, 2 volumes of 
 eulphydric or hydrochloric acid gas, 8 volumes of hydrogen in excess, 9 volumes of 
 oxygen in excess, or 11 volumes of carbonic oxide: 5 measures of aqueous vapour do 
 not destroy the inflammability of 1 measure of detonating gas (H. Davy). According to 
 
COMBUSTION. 1101 
 
 Humboldtand Gay-Lussac (Gilb. Ann. xx. 49), the inflammability of one volume cf 
 detonating gas is destroyed by the admixture of 5 volumes of oxygen, or 4*7 volumes 
 of hydrogen gas. Marsh-gas is no longer inflammable by the electric spark, when it 
 is mixed with 11 measures of oxygen instead of the 2 measures which it actually 
 requires to combine with it (H. Davy). Coal gas burns continuously in a mixture 
 of 1 measure of oxygen and 7 of nitrogen, but is extinguished when the quantity of 
 the latter amounts to 8 measures ; it burns in a mixture of 1 measure of oxygen with 
 3, but not with 4 measures of hydrochloric acid gas ; with 2|, but not with 3 measures 
 of carbonic acid : with 2, but not with 2|- measures of fluoride of silicium. The greater 
 the density of the inactive gas, the smaller is the quantity which suffices to stop the 
 combustion ; because the combustible gas diffuses itself more readily through a heavy 
 than through a light gas, and therefore cools down the faster (Wai die). A lighted 
 candle is extinguished in air to which | of its volume of hydrochloric acid gas, or i of 
 fluoride of silicium, has been added. When combustible bodies burn in a confined 
 space, the relative quantity of nitrogen, &c. becomes increased, partly by consumption 
 of oxygen, partly by formation of gaseous products of combustion, such as carbonic 
 acid, sulphurous acid, &c. ; and thus the combustion is brought to an end. In one and 
 the same limited space, a candle goes out first, then hydrogen gas, then sulphur ; while 
 the slow combustion of phosphorus will go on as long as the smallest quantity of 
 oxygen remains. (H. Davy.) 
 
 5. Solid burning bodies are extinguished when laid on good-conducting supports, 
 e. g. glowing coals on considerable masses of metal. A mixture of a combustible gas 
 and oxygen will not take fire in very narrow tubes, because their sides cool down too 
 quickly: this is the principle of the oxy-hydrogen blow-pipe (i. 616). From the 
 same cause, the flame of a mixture of combustible gases and common air is often 
 unable to pass through the meshes of wire-gauze : the passage of the flame takes place, 
 however, with greater facility, the lower the temperature at which the gas takes fire, 
 the greater the heat evolved by its combustion, the more quickly it is forced through 
 the apertures by pressure or draught, the wider the meshes, the smaller the mass and 
 specific heat of the metal of which the gauze is made, and the higher its temperature. 
 Above a certain temperature, all flames pass through it. The flame of a cotton thread 
 may be extinguished by holding over it, even at some distance, a ring of fine iron wire, 
 or a thicker ring of glass (Davy). On this impenetrability of wire-gauze by the 
 flame of light carburetted hydrogen gas in coal-mines, is based the Safety-lamp of 
 Sir H. Davy, which consists essentially of a common oil-lamp having its flame sur j 
 rounded by a cylinder of wire-gauze. When this lamp is taken to a part of the mine con- 
 taining an explosive mixture of gas and air, the interior of the cylinder becomes filled 
 with a blue flame ; but this flame is not communicated to the explosive mixture outside, 
 because it is cooled down below the burning temperature in its passage through the 
 meshes of the gauze. (See the article SAFETY LAMP, in Ure's Dictionary of Arts, 
 Manufactures, and Mines, iii. 612; also Ronald's and Richardson 's Chemical Technology^ 
 i. [2] 511.) 
 
 The same principle is applied in many elegant contrivances now in use in chemical 
 laboratories for burning a mixture of gas and air, so as to produce a hot smokeless 
 flame (p. 1095), the mixture of gas and air being made to pass through a sheet of wire 
 gauze, and set on fire at the other side, so that the flame cannot extend to the orifice 
 whence the gas issues. 
 
 Motion of the air, produced by draught or by the bellows, accelerates combustion 
 and increases the intensity of the heat, by continually bringing fresh portions of air 
 in contact with the burning body. Very rapid motion of the air may however extin- 
 guish combustion, either by the cooling if the quantity of air supplied in a given 
 time is such that the burning body cannot in the same time consume the whole of 
 its oxygen ; or by blowing the burning vapour away from its source, so that the flame 
 can no longer communicate with the fresh matter which issues. 
 
 Fire-extinguishing substances act either by cooling, as water does, or by covering 
 the burning body and thereby impeding the access of air as when a rug or other not 
 easily combustible body is thrown on a mass of light burning materials, or when a fire 
 is choked with earth or ashes ; or lastly by surrounding the burning mass with an 
 atmosphere not containing oxygen. This is the principle of Phillips' s Firc-annihilator, 
 in which a mixture of 20 pts. charcoal, 60 pts. saltpetre, and 5 pts. gypsum, is 
 set on fire by means of chlorate of potash, sugar, and sulphuric acid, the heat pro- 
 duced by the combustion being made at the same time to convert into vapour a 
 quantity of water contained in the apparatus. The result is the instantaneous pro- 
 duction of a large quantity of steam, carbonic acid and other inactive gases, which can 
 be at once directed on the burning mass. (See Ure's Dictionary of Arts, Manu- 
 factures, and Mines, ii. 212.) 
 
 With regard to the efficiency of steam in extinguishing fires, Mr. Graham observes 
 
1102 COMENAMETHANECOMENAMIC ACID. 
 
 in his " Eeport on the fire in the Amazon," already quoted (p. 1094), that " steam can 
 only be said to be efficient in extinguishing flame, or a blaze from light objects, and 
 is not to be relied on beyond an early stage of a fire. Upon a mass of red-hot cinders, 
 the extinguishing effect of steam is insensible." The same is probably true with re- 
 gard to carbonic acid, nitrogen, and other gases. 
 
 Method of diminishing the inflammability of light fabrics. Much attention has 
 lately been devoted to the problem of rendering muslin and other light fabrics non-in- 
 flammable, with the view of preventing the terrible accidents, which so frequently arise 
 from ladies' dresses coming in contact with the flame of a candle or the fire in a 
 grate. This object is attained by steeping the fabric in a saline solution, and then 
 drying it in the ordinary way. The fibre is thereby surrounded with a crust of in- 
 combustible matter, which prevents it from taking fire by momentary contact with a 
 bxirning body, and causes it, even if held in a flame, to burn with a slow smouldering 
 combustion, without bursting into flame. 
 
 Almost any salt will produce this effect, but the greater number are unfit for appli- 
 cation to articles of dress, because they injure the texture, rendering the fabric harsh, 
 and destroying all its beauty. The salt which is found to answer most completely all 
 the required conditions, is the neutral tungstate of sodium. Muslin steeped in a 
 solution containing 20 per cent, of this salt is perfectly non-inflammable when dry, 
 and the saline film left on its surface is smooth and of a fatty appearance like talc, 
 and therefore does not interfere with the process of ironing, but allows the hot iron to 
 pass smoothly over the surface. The non-fulfilment of this latter condition com- 
 pletely prevents the use of many other salts such as sulphate and phosphate of 
 ammonium, which are otherwise efficacious in destroying inflammability for all 
 fabrics which have to be washed and ironed. 
 
 The use of the tungstate of sodium for this purpose offers but one difficulty, viz. the 
 formation of an acid tungstate of little solubility. This inconvenience may, however, 
 be obviated by the addition of a small quantity of phosphoric acid or phosphate of 
 sodium. The best way of preparing a solution of minimum strength for the purpose, 
 is to dilute a concentrated solution of the neutral tungstate with water to 28 Twaddell, 
 and then add 3 per cent, of phosphate of sodium. The solution is found to keep, and 
 to answer its purpose well; it is now constantly used in Her Majesty's laundry 
 (Versmann and Oppenheim, Communication read before the British Association 
 at Aberdeen, 15th Sept. 1859 ; Pharm. J. Trans. [2] i. 385). The use of phosphate of 
 ammonium for preserving light fabrics from ignition was proposed, many years ago, by 
 Gay-Lussac. 
 
 COIVEENrjfi.lVIETHATrE. Syn. with COMENAMATE OF ETHYL. 
 COlttEBTAMIC ACID, C"H 6 N0 4 + 2H 2 = N - H2 -(C 6 H0 3 )" 
 
 Ed. Phil. Trans, xx. [2] 225 ; Ann. Ch. Pharm. Ixxx. 65.) This acid is produced by 
 the dehydration of acidcomenate of ammonium, C 6 H 8 (NH 4 )0 5 -H 2 = C 6 H 5 NO 4 . It 
 may be prepared by heating the salt to 199 C. in a sealed tube, and precipitating 
 the aqueous extract with hydrochloric acid ; or better, by boiling aqueous comenic 
 acid with excess of ammonia till nearly all the ammonia is expelled, collecting on a 
 filter the grey argillaceous sediment of comenamate of ammonium and colouring matter, 
 and dissolving it in hot water ; decomposing the solution with hydrochloric acid not in 
 excess ; and purifying the precipitated dark brown scales of impure comenamic acid 
 by repeated crystallisation from hot water, and treatment with animal charcoal free 
 from iron. The crystals contain 2 atoms water (18'81 per cent.), and give it off at 
 100 C. They dissolve sparingly in cold, more freely in hot water, forming a solution 
 which reddens litmus strongly. The acid dissolves in boiling alcohol of ordinary 
 strength, but is nearly insoluble in boiling absolute alcohol. 
 
 The acid is decomposed by boiling with potash, yielding ammonia and comenate of 
 potassium. It dissolves readily in hydrochloric acid and other strong mineral acids, 
 and is precipitated therefrom by ammonia in quantity rather less than sufficient for 
 saturation, as comenamate of ammonium. 
 
 Comenamic acid is monobasic, the normal salts being C 6 (H 4 M)N0 4 . There are also 
 several basic salts. The ammonium-salt, C 6 H 4 (NH 4 )N0 4 forms small grains made up 
 of delicate needles nearly insoluble in cold water ; their solution reddens litmus. The 
 potassium- and sodium-salts crystallise readily and redden litmus. The normal barium- 
 salt, C 6 H 4 BaN0 4 , obtained by mixing a solution of the crystallised ammonium-salt with 
 chloride of barium, forms crystals with 1 at. water, which redden litmus. A basic 
 barium-salt, C 6 H 4 BaN0 2 .BaHO + pI 2 0, is formed, by mixing chloride of barium 
 with an ammoniacal solution of comenamate of ammonium, as a white heavy pre- 
 cipitate, which gives off its water (2'83 per cent.) at 100 C. The aqueous acid left in 
 
COMENIC ACID: 1103 
 
 contact with carbonate of barium forms the normal or the basic salt according to the 
 relative quantities. With lime, it forms two salts of similar constitution. 
 
 The ammonium-salt forms, with acetate of lead, a heavy insoluble precipitate. 
 
 Comenamic acid imparts to ferric salts a deep purple colouring, which is destroyed 
 by mineral acids, but reproduced by water. 
 
 The crystallised ammonium-salt forms a grey precipitate with sulphate of copper. 
 
 The ammonium-salt super-saturated with ammonia forms, with nitrate of silver, a 
 yellowish flocculent, quickly blackening precipitate ; and the crystallised ammonium- 
 salt forms a white gelatinous precipitate, which is partially decomposed by boiling 
 water. 
 
 Comenamate of Ethyl, Comenamic ether, Comenamcthane, C 8 H 9 N0 4 = 
 C 8 H'(C 2 H 5 )N0 4 . (How. Ed. M. Phil. J. i. 212.) When a solution of comenamic acid in 
 absolute alcohol is treated with dry hydrochloric acid gas, and the liquid subsequently 
 evaporated, there remains an oil which dries up at 100 C. to a solid mass, and when 
 dissolved in alcohol, yields a hydrochlorate of comenamic ether, C 8 H 9 N0 4 .HC1 + IPO ; 
 and on treating this compound with oxide of silver, or with ammonia (not in excess), 
 comenamic ether is obtained in needle-shaped crystals containing 1 at. water, which 
 they give off at 100 C., leaving the anhydrous ether. When the solid mass above men- 
 tioned is treated with water, comenamic acid remains undissolved, and another portion 
 of that acid separates as a crystalline powder from the solution, which contains hydro- 
 chloric acid. 
 
 The ether is neutral ; melts to a yellow liquid when heated ; is not altered by 
 ammonia in the cold; and is converted by nitric acid into oxalate of ammonia. It 
 dissolves sparingly in cold water, readily in hot water and in mineral adds, sparingly 
 in absolute alcohol. 
 
 A compound of this ether with hydriodic acid is obtained by heating iodide of 
 ethyl with a solution of comenamic acid ia absolute alcohol to 150 C., in sealed tubes. 
 
 ACID. C 6 H 4 S = 2 , or C J2 H*0" = W*H*O*.1HO. Pa- 
 
 rameconic acid, Anhydrous Meconic acid. (Robiquet, Ann. Ch. Phys. [2] li. 326; 
 liii. 428. Liebig, Ann. Ch. Pharm. vii. 237; xxvi. 116. Stenhouse, Phil. Mag. 
 [3] xxv. 196. H. How, Ed. Phil. Trans, xx. [2] 225. Gm. xi. 328. Gerh.ii. 182.) 
 
 Comenic acid was discovered in 1832, by Robiquet, who at first regarded it as anhy- 
 drous meconic acid ; it was afterwards recognised as a distinct acid by Liebig, who first 
 observed the formation of carbonic acid which accompanies the conversion of meconic 
 into comenic acid. It is produced: 1. By heating meconic acid to temperatures 
 between 120 and 220 C., the change being attended with evolution of carbonic anhy- 
 dride: 
 
 C'H'O 7 - C 6 H<0 5 + CO 2 . 
 
 2. By continued boiling of meconic acid dissolved in water or in hydrochloric acid, 
 likewise with evolution of carbonic acid. (Eobiquet.) 
 
 Preparation. Meconic acid or its potassium or barium-salt, is boiled with a strong 
 mineral acid ; or meconate of calcium is boiled with highly concentrated hydrochloric 
 acid (Stenhouse) ; or acid meconate of potassium, produced by treating crude neutral 
 meconate of calcium with very dilute hydrochloric acid, is heated with as much strong 
 hydrochloric acid as is required to dissolve it (How), and the solution is left to crystal- 
 lise. When the mere aqueous solution of the acid is boiled, too large a quantity of 
 brown secondary product is formed. (Kobiquet, Liebig.) 
 
 To purify the product, the still reddish crystals are dissolved in a slight excess of hot 
 concentrated potash ; the solution is filtered hot to separate a small quantity of lime ; 
 the white nodules which form on cooling are washed with a small quantity of cold 
 water, till the strongly coloured mother- liquor is rem'bved, then boiled with excess of 
 hydrochloric acid ; and the comenic acid which separates on cooling is freed from 
 hydrochloric acid by two or three recrystallisations from water. The still remaining 
 tinge of red may be removed by treatment with animal charcoal (Stenhouse). Or, 
 the impure acid is dissolved in a quantity of boiling ammonia just sufficient to dis- 
 solve it (an excess, as well as continued boiling, causes the liquid to turn brown), and 
 filtered immediately at the boiling heat ; the yellow crystals which separate from the 
 dark filtrate when left at rest, are washed with cold water and recrystallised from 
 hot water ; their pale-yellow aqueous solution is mixed with strong hydrochloric acid ; 
 and the comenic acid, which is precipitated in the form of a white or pale yellow powder, 
 is crystallised from boiling water. 
 
 Properties. Comenic acid forms anhydrous prisms, laminae, or granules, having a 
 very faint yellowish colour, requiring more than 16 pts. of boiling water to dissolve 
 them ; sparingly soluble in hydrated alcohol, but insoluble in absolute alcohol. 
 
 Decompositions. I. The acid, when subjected to dry distillation, behaves like 
 meconic acid (Robiquet). When comenic (or meconic) acid is quickly heated in a 
 
1104 COMENIC ACID. 
 
 retort, above the temperature of 200 to 220 C., at which pyromoconic acid would be 
 formed, but not till complete carbonisation takes place, an acid yellowish watery 
 liquid passes over, having a faint empyreumatic odour ; and there remains a blackish 
 grey, porous, carbonaceous mass, from whose ammoniacal solution, after filtration, 
 hydrochloric acid throws down thick dark green flakes, which, if exposed to the air 
 after washing with water, shrink up to a substance resembling glance-coal in appearance, 
 and in its chemical relations agreeing perfectly with metagallic acid (Winckler, 
 Report. 59, 42). 2. Comenic acid suspended in water through which a stream of 
 chlorine gas is passed, forms a solution of chlorocomenic acid, which crystallises out 
 after a while, and oxalic acid, which remains in solution : 
 
 C 6 H 4 5 + Cl 2 = C 6 H 3 C10 5 + HC1. 
 
 The oxalic acid and a brown colouring matter which forms during evaporation must 
 be regarded as secondary products (How). 3. Similarly, the colourless solution of 
 comenic acid in bromine-water yields bromocomenic acid which crystallises, and oxalic 
 acid (How). 4. Nitric acid, even when very dilute, converts comenic acid into 
 carbonic, hydrocyanic, and oxalic acids ; and if the nitric acid is tolerably strong, and 
 heated at the beginning of the action, the process is complete in a few minutes 
 (How). 5. Strong sulphuric acid acts upon comenic acid in the same manner as on 
 meconic acid. (R o b i q u e t). 6. The acid dissolved in water and boiled with excess of 
 ammonia till nearly all the ammonia evaporates, forms a black-red liquid, which, on cool- 
 ing, deposits impure comenamate of ammonium as a grey viscid sediment. (How, p. 96.) 
 
 Co ME NATES. Comenic acid is dibasic, forming neutral or normal salts, C 6 H 2 M 2 O 5 , 
 and acid salts, C 6 H 3 M0 5 . The neutral comenates of the alkali-metals cannot be 
 obtained in the solid state. 
 
 Acid Comenate of Ammonium, C 6 H 3 (NH 4 )0 5 , is obtained in How's process for 
 purifying comenic acid. The aqueous acid slightly supersaturated with ammonia, 
 and evaporated in vacuo over oil of vitriol, yields four-sided prisms having a yellowish 
 tinge; they give off 9'04 per cent. (1 at.) water at 100 C. (Stenhouse). The salt 
 forms white square prisms having a very strong lustre ; they redden litmus even when 
 they separate on cooling from a hot solution of the acid in excess of ammonia. They 
 do not give off anything at 177 C., but at 199, in a sealed tube, they melt and are 
 converted into a black mixture of charcoal and comenamate of ammonium ; their 
 aqueous solution is also converted into this salt by continued boiling with ammonia 
 (p. 1100). They dissolve readily in boiling water, sparingly in alcohol. (How.) 
 
 Comenates of Barium, a. Neutral. C 6 H 2 Ba 2 5 + H 2 (at 121 C.). Chloride 
 of barium mixed with a solution of the acid in excess of ammonia throws down imme- 
 diately or in very dilute solutions, after some time only yellowish quadratic needles 
 united in concentric groups. These crystals do not lose water at 100 C., but at 121, 
 they give off 19 '03 per cent, water, and if then heated to redness in the air, burn 
 away in a fiery cloud. They do not dissolve in boiling water, but when boiled with 
 it, are converted into a basic salt, which does not give off water at 121 C., and con- 
 tains 54*5 per cent, baryta. (How.) 
 
 0. Acid salt. C 6 H 3 Ca0 5 (at 100 C.). The free acid does not precipitate barium- 
 Baits (Stenhouse). The salt is produced when baryta is boiled with excess of the 
 acid. Chloride of barium mixed with a cold-saturated aqueous solution of the crys- 
 tallised ammonium-salt immediately forms a crystalline precipitate, and with a more 
 dilute solution, gradually deposits transparent crystals, which give off their 20-86 
 per cent, (somewhat more than 3 at.) water at 100 C., and melt at a stronger heat. 
 (How.) 
 
 Comenate of Calcium, a. Neutral. C 6 H 2 Ca 2 5 + H 2 (at 121 C.) The acid 
 supersaturated with ammonia, precipitates from chloride of calcium, if the solutions 
 are saturated, very short prisms which give off 18-20 per cent, (f at.) water at 121 C. r 
 and when the solutions are dilute, small shining crystals, which at 121 give off 31*37 
 per cent. (5 at.) water. The two kinds of crystals are insoluble in water, but become 
 basic when boiled with water. 
 
 0. Acid salt. C 6 H 3 Ca0 5 (at 121 C.) A mixture of chloride of calcium and a cold 
 saturated aqiieous solution of the crystalline ammonia-salt, quickly deposits trans- 
 parent, shining, rhombic crystals, which give off their water slowly at 100, but the 
 whole, amounting to 26-15 per cent. (f at.) at 121. They dissolve readily in boiling 
 water, and crystallise therefrom on cooling. 
 
 Comenate of Copper. C 6 H 2 Ca 2 5 + H 2 (at 100 C.) The dark green aqueous 
 mixture of cupric sulphate and comenic acid (or the crystallised ammonium-salt, ac- 
 cording to How) deposits, after a few minutes, elongated pyramids having the colour 
 of Schweinfurt green. No acid comenate of copper appears to exist. (How.) 
 
 Comenates of Iron. Ferric Comenate. Fe 2 3 .4C 6 H 4 O 5 -f 3H 2 O, or \\ife = 
 |Fe] = /e 2 0.4C B Hyc0 5 + 5H 2 (at 100 C.) Comenic acid imparts a bright red 
 
COMENIC ACID. 1105 
 
 colour to ferric salts. The dark blood-red mixture of ferric sulphate with a cold- 
 saturated solution of comenic acid or its ammoniacal salt, becomes paler by long 
 standing, and deposits small pitch-black, 1 shining, very hard, nearly tasteless crystals, 
 which grate between the teeth, yield a dark brown powder, and dissolve slowly both 
 in cold and in hot water, forming a pale red solution. (Stenhouse.) 
 
 The red mixture of aqueous comenic acid with ferric sulphate, becomes dark yellow 
 at 65 C. (and gives off carbonic acid, according to How), by conversion of all the 
 sesquioxide of iron into protoxide at the expense of the acid, part of which at first 
 remains undecomposed, so that a fresh portion of ferric sulphate again produces 
 reddening. This colour, however, disappears when the liquid is digested for twelve 
 hours with excess of ferric sulphate, in consequence of the complete conversion of co- 
 menic acid into another add; hence the no longer red liquid deposits small, pale 
 yellow, shining crystals of a ferrous salt (probably ferrous oxalate, as the liquid con- 
 tains oxalic acid, according to How), which burn away when heated, and dissolve 
 sparingly in water ; the acid of these crystals extracted by potash no longer reddens 
 ferric salts. (Stenhouse.) 
 
 Comenate of Lead. The acid and its ammonia-salt form with neutral acetate of 
 lead a yellowish white granular precipitate, soluble in excess of comenic acid, but not 
 in acetic acid. (Stenhouse.) 
 
 A lead-salt examined by Robiquet contained 54-1 per cent, oxide of lead. 
 
 Comenates of Magnesium, a. Neutral. C 6 H 2 Mg 2 5 + |H 2 (at 100 C.) 
 Sulphate of magnesium forms with the acid saturated with ammonia, especially when 
 the mixture is stirred, hard, closely adhering, crystalline grains, consisting of short mi- 
 croscopic needles. These crystals heated to 100, slowly give off 26*50 per cent. 
 (4 at.) water ; and if then kept at 121 for four days, they give off such a quantity 
 [nearly f at.] that the residual salt contains 21-30 per cent, magnesia, and is there- 
 fore not quite anhydrous. They are not soluble in boiling water. (How.) 
 
 0. The acid salt, C 6 H 3 Mg0 5 + H 2 (at 100 C.), crystallises, after a while, from a 
 mixture of sulphate of magnesium with the cold-saturated solution of the crystalline 
 ammonia-salt, in small rhombs, and from more dilute solutions, on evaporation, in 
 larger crystals, which are strongly acid, give off 22'08 per cent. (3 at.) water at 116, 
 and dissolve readily in hot water. (How.) 
 
 Comenic acid does not precipitate mercuric chloride. (Stenhouse.) 
 
 Comenates of Potassium, a. Neutral. C 6 H 8 K 2 5 . The aqueous acid half 
 neutralised with potash, so as to form the mono-potassic salt, yields no precipitate, but 
 when completely neutralised, deposits the sparingly soluble dipotassic salt. In this 
 respect, comenic acid is opposite to meconic acid, the acid potassium-salt of which is 
 the less soluble of the two. (Kobiquet.) 
 
 /8. Acid salt. C 8 H 3 K0 5 . The acid, dissolved in a slight excess of boiling potash-ley, 
 yields crystals on cooling, which, after washing with cold water, crystallise from hot 
 water in short, square, anhydrous needles, which redden litmus. (How.) 
 
 Comenates of Silver. The neutral salt, C 6 H 2 Ag 2 5 , is obtained by exactly pre- 
 cipitating a solution of nitrate of silver with comenic acid neutralised with ammonia. 
 The thick yellow precipitate does not detonate when heated. (Liebig.) 
 
 The acid salt, C 6 H 3 Ag0 5 , is the precipitate (white, granular, or flocculent, according 
 to Stenhouse) which the free acid produces in solution of nitrate of silver. (Liebig.) 
 
 Comenate of Sodium. The solution of the acid in tolerably strong boiling soda- 
 ley yields, on cooling, nodules and prisms, which, after washing with a little cold water, 
 crystallise from the smallest possible quantity of hot water, in acid, anhydrous, four- 
 sided prisms, containing 17'09 per cent, soda, and therefore = C 8 H 3 Na0 5 . (How.) 
 
 Comenates of Strontium. The neutral and acid salts closely resemble the cor- 
 responding barium-salt, but are more soluble. 
 
 Substitution-derivatives of Comenic Acid. 
 
 BBOMOCOMENIC ACID. C 6 H 3 Br0 5 . (How, loc.cit.) The colourless solution of 
 comenic acid in a slight excess of bromine-water deposits, after a few hours, oily, 
 colourless, shining, strongly refracting, four-sided prisms, which dissolve in water and 
 in alcohol less easily than chlorocomenic acid ; they give off their water of crystallisa- 
 tion at 100 C. 
 
 The acid is decomposed by nitric acid, yielding hydrobromic, carbonic, hydrocyanic, 
 and oxalic acids. With zinc and water it decomposes like chlorocomenic acid. 
 
 Bromocomenic is dibasic, like comenic acid. The acid bromocomenates of ammonium, 
 potassium, and sodium are crystallisable ; the first crystallises in long needles. The 
 neutral salts of these bases are not obtainable. 
 
 The neutral bromocomenates of barium and calcium are amorphous and insoluble ; 
 the add salts are very easily soluble. 
 
 VOL. I. 4 B 
 
1106 COMENIC ACID. 
 
 The solution of the acid in a slight excess of ammonia yields, with nitrate of silver, N 
 neutral bromocomenate of silver in the form of a yellow precipitate having the con- 
 sistence of clay when dry ; and the solution of the acid in warm water forms with 
 nitrate of silver, flakes of the acid salt, C 6 H 2 AgBr0 5 , which crystallises from boiling 
 water in short shining prisms. 
 
 CHLOROCOMENIC ACID. C 8 H S C10 5 . (How, loc. cit.} Obtained bypassing 
 chlorine through water in which pulverised comenic acid is suspended, washing the 
 crystals which separate with cold water, and recrystallising from hot water, or by pass- 
 ing chlorine into cold water saturated with acid comenate of ammonium ; the liquid 
 then acquires the colour of chlorine-water, and gradually deposits crystals of chloro- 
 comenic acid, which increase on addition of hydrochloric acid, and may be purified 
 as in the first process. The mother-liquor becomes continually browner, and still 
 deposits brown crystals of the acid. 
 
 The crystals are long, colourless, shining, four-sided prisms, containing 12 '4 7 per 
 cent. (| at.) water, which they give off at 100 C. They dissolve both in cold and 
 in hot water, more readily than comenic acid ; very easily in warm alcohol. 
 
 The acid melts when heated, blackens, gives off a large quantity of hydrochloric 
 acid, and at last yields a small crystalline sublimate, probably consisting of para- 
 comenic acid. By nitric acid it is quickly converted into hydrochloric, carbonic, hy- 
 drocyanic, and oxalic acids. Its aqueous solution, treated with zinc, slowly gives off 
 hydrogen, and afterwards contains hydrochloric acid and oxide of zinc. 
 
 Chlorocomenic acid is dibasic, forming neutral salts, C 6 HM 2 C10 5 , and acid salts, 
 CVH-MCIO 5 . 
 
 The chlorocomenatcs resemble the comenates, but dissolve more readily in water. 
 
 The acid chlorocomenates of ammonium, potassium, and sodium crystallise readily. 
 The neutral salts are not obtainable. 
 
 The ammonium-salt forms with chloride of barium and chloride of calcium, bundles 
 of needles which appear more or less quickly, according to the degree of concentration ; 
 with sulphate of magnesium, it gradually forms a few crystals ; and with cupric sul- 
 phate, immediately, a crystalline precipitate. The neutral chlorocomenates of these 
 bases appear to be all amorphous and insoluble. 
 
 The acid colours ferric salts deep red, like comenic acid. 
 
 Silver-salts, a. Neutral. The acid dissolved in a slight excess of ammonia forms, 
 with nitrate of silver, yellow amorphous flakes, which, after drying, resemble clay in 
 appearance, consistence, and tenacity. The salt dried at 100 C. contains 56'85 per 
 cent, silver, and is therefore C 6 HAg 2 C10 5 . When ignited in the air, it leaves silver, 
 together with a small quantity of chloride of silver; when boiled with hydrochloric 
 acid, it remains partly uiidecomposed. It is insoluble in boiling water, but dissolves 
 in nitric acid, from which, if heated with the salt, it separates cyanide of silver. 
 
 b. Acid. The warm aqueous acid added to solution of nitrate of silver throws 
 down feathery crystals, which, after washing with cold water, separate from boiling 
 water in short shining needles. These crystals give off 4 '44 per cent, water at 100 C 
 When ignited, they leave silver and chloride of silver. 
 
 ETHYLCOMENIC ACID. C 8 H 8 5 = C 6 H 3 (C 2 H 5 )0 5 (How, loc. cit.\ To prepare 
 this acid, dry hydrochloric acid gas is passed through absolute alcohol in which pulverised 
 comenic acid is suspended, till the acid dissolves, which takes place slowly; the clear 
 liquid (which deposits nothing on addition of water) is evaporated at a temperature 
 below 100 C. ; the crystalline residue is maintained at this temperature, till it no 
 longer smells of hydrochloric acid, and then left to crystallise by cooling from its solu- 
 tion in water at nearly 100. Or, pulverised comenic acid, heated with alcohol and 
 iodide of ethyl in a closed vessel to a temperature above 100, forms a granular deposit 
 consisting of an acid not yet examined, and ethylcomenic acid, in needle-shaped 
 crystals, which may be separated and purified by recrystallisation. Similar products 
 are obtained by heating a mixture of comenic acid, alcohol, and chloride of amyl to 
 160 for 12 hours. 
 
 The acid forms large square needles, which begin to evaporate at 100 C. ; melt at 
 135 into a clear brown-red liquid, which solidifies again in the crystalline form on 
 cooling ; and if kept for a longer time at 135, sublime in long flat unaltered needles, 
 having the same composition. It is very soluble in water and alcohol, and reddena 
 litmus ; the aqueous solution coagulates albumin. 
 
 The acid may be boiled for a short time without alteration, but if boiled for a longer 
 time, it yields free comenic acid. With aqueous solutions of the fixed alkalis, even 
 in the cold, it very quickly forms salts, and yields free alcohol. 
 
 When ammoniacal gas is passed through a solution of the acid in absolute alcohol, 
 the ammonia salt is deposited in yellow silky bundles of needles, which give off am- 
 monia in dry air, and almost completely in vacuo over oil of vitriol, leaving ethyl- 
 comenic acid. 
 
COMPTONITE CONCRETIONS. 1 107 
 
 The acid imparts a deep red colour to ferric salts. Its silvcr*salt is gelatinous, and 
 decomposes very quickly, even in the dark. 
 COlttPTONITE. See THOMSONITE. 
 
 CONCENTRATION. A process which has for its object to increase the amount 
 of a dissolved substance in a liquid, relatively to the quantity of the solvent, without 
 adding any more of the dissolved substance itself. When the solvent is volatile, this 
 object is effected by evaporation, as when water, alcohol, or ether is expelled from a 
 solution by heat, by exposure to the air, or in vacuo. If the dissolved substance is 
 more volatile than the solvent, the concentration is effected by distillation, the more 
 concentrated liquid being then found in the distillate, as in the rectification of hydrated 
 alcohol and of volatile oils dissolved in water. In the case of aqueous liquids, concen- 
 tration is sometimes effected by freezing out the water ; in this manner, a strong solu- 
 tion of salt maybe obtained from sea- water; strong spirit from vinous liquids, &c. 
 
 A similar principle is applied to the separation of silver from lead. The argenti- 
 ferous lead is melted and left to cool, till about two-thirds of the mass is solidified ; 
 this consists of nearly pure lead, the portion which still remains liquid being an alloy 
 richer in silver than the original mass. By repeating this operation several times, the 
 alloy at last becomes sufficiently rich in silver to be treated by cupellation. 
 
 CONCHIOIiIN*. An organic constituent of the shells of certain molluscs', first 
 observed by Fremy. It closely resembles keratin, or epidermose ; does not yield gelatin 
 by boiling with water, even under strong pressure ; is insoluble in water, alcohol, ether, 
 acetic acid, dilute mineral acids, and potash-ley. It contains 50 per cent, carbon, 
 6 hydrogen, and 16 to 16 - 7 nitrogen, a composition very near to that of epidermose : 
 whether it contains sulphur does not appear to have been made out. A similar sub- 
 stance, but containing only 12 or 13 per cent, nitrogen, was found by Schlossberger in 
 the byssus of acephalous molluscs. 
 
 CONCRETIONS, ANXIKCAIi. This term is applied to all deposits in the animal 
 
 n' which are destitute of distinct organic structure. They are almost always of 
 id character, a few only, as the brain-sand (the sabulous matter of the pineal 
 gland), the crystals in the auditory organs of most animals, and in the vertebral 
 column of frogs, appearing to occur in healthy animals. 
 
 Concretions are formed: 1. In the liquid secretions, as urinary, salivary, and biliary 
 calculi, concretions in the stomach and intestines, in the lachrymal ducts, the cavity of 
 the nose, the sebaceous glands of the skin (gouty concretions), &c. 2. In the cellular 
 tissue of the organs, as in the brain, heart, veins, lungs, and indeed in all parts of the 
 body. These latter are formed by the gradual transformation of other morbid products 
 the animal matter of which is gradually absorbed, while the inorganic substance 
 remains, and is often increased by addition of fresh deposits. All concretions of this 
 kind have a very similar, indeed almost identical, constitution, consisting of a base 
 sometimes predominant, sometimes subordinate, of coagulated fibrin, with deposits of 
 phosphate and carbonate of calcium, ammonio-magnesian phosphate and carbonate of 
 magnesium, in variable proportions. Another class of concretions allied to those last 
 mentioned, are the so-called asteromatose deposits in the coatings of the arteries, 
 especially of the aorta. They are sometimes, but not always, associated with calcareous 
 deposits, and form layers of yellowish-white colour, and very slight consistence. 
 They consist mainly of crystalline deposits of cholesterin. 
 The essential constituents of animal concretions are . 
 
 Uric acid and its salts. 
 
 Xanthin and cystin. 
 
 Hippurates and benzoates. 
 
 Cholesterin and fat. 
 
 Bile-pigment or cholochrome. 
 
 Fibrin. 
 
 Phosphate of calcium ; ammonio-magnesian phosphate ; oxalate of calcium ; 
 carbonate of magnesium. 
 
 The following substances occur as cements or less essential constituents : urinary 
 and gall-bladder mucus, albumin, blood-red, the biliary acids, animal matter of inde- 
 terminate character, and sometimes soluble salts. 
 
 The chemical analysis of animal concretions must always be preceded by an examina- 
 tion of their physical structure. They are very often made up of concentric layers of 
 substances differing in chemical constitution, so that it becomes necessary to make a 
 separate analysis of each layer. 
 
 As respects their behaviour when heated, concretions are distinguished as 1. Per- 
 fectly combustible. 2. Partially combustible 3. Incombustible. Their special chemical 
 characters are given in the following tables. (Handw. d. Chem. ii. [2] 171.) 
 
 4 u2 
 
1108 
 
 CONCRETIONS : ANIMAL. 
 
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CONCBETIONS: ANIMAL. 
 
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 Ss-pfj 
 
 ^111 
 
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 gg's^S;: 
 
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 rd 
 
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 sill^l 
 
 sJ-jilii 
 
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 O 08, 
 
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1 1 10 CONDENSATION CONGLOMERATE. 
 
 CONDEW3ATIOW. This term, in its most general sense, implies increase of 
 density, but: it is often restricted to the passage of a gas to the liquid or solid state. 
 
 COXTDRODXTE. See CHONDRODITE. 
 
 COWDURRITB. A mineral containing copper and arsenic, originally obtained 
 from the Condurrow mine near Helstone, in Cornwall ; since found in the Huel Druid 
 mine, near Hedruth ; also in mines at Coquimbo and Copiapo, Chili. It forms amor- 
 phous, roundish, flattened nodules, with flat conch oi'dal fracture, brownish-black colour, 
 bluish-black on the outer surface, opaque, dull or with glimmering lustre ; streak me- 
 tallic; powder brownish-black ; soft. Specific gravity, 4-2 5'2. 
 
 Condurrite has been frequently analysed, but with very variable results ; in fact it 
 appears to be a mixture resulting from the alteration of Domeykite (Cu 6 As), and mainly 
 consisting of a hydrated cuprous arsenite mixed with small quantities of manganese, 
 sulphur, iron, and silica. (Kopp, Handw. d. Chem. ii. [3], 173.) 
 
 A geological term applied to masses of rounded fragments 
 of older rocks held together by a cement ; if, on the other hand, the fragments are for 
 the most part sharp-edged, the mass is called breccia. Conglomerates are distin- 
 guished as quartzose, calcareous, dolomitic, granitic, syenitic, &c., according to the 
 nature of the component fragments : the cement may be siliceous, calcareous, or argilla- 
 ceous. 
 
ADDENDA. 
 
 ACETYXEKTE. C 2 H 2 . A gaseous hydrocarbon, which appears to have been 
 first obtained by E. Davy (Eecords of gen. Sci. Nov. 1836; Gm. viii. 150), 
 though in an impure state, by the action of water on the black substance which 
 passes over in the preparation of potassium; but its preparation in the pure 
 state, and indeed the establishment of its existence as a definite compound, is due to 
 Berthelot (Institut, 1859, p. 410; 1860, p. 565 ; Kep. Chim. pure, ii. 222 ; Ann. Ch. 
 Pharm. cxv. 116), who obtained it by passing ethylene-gas, or the vapour of ether, 
 alcohol, aldehyde, or wood-spirit, through a red-hot tube, and by the action of red-hot 
 copper on chloroform. Ether yields it in largest quantity, but by whichever of the 
 preceding methods it is produced, it is always mixed with a considerable quantity of 
 other gases, and requires to be purified by passing the gaseous mixture into an 
 ammoniacal solution of cuprous chloride ; a red precipitate is then formed which, when 
 decomposed by hydrochloric acid, yields pure acetylene. 
 
 Berthelot has further shown that acetylene is one of the constituents of coal-gas, and 
 that it may be formed by the direct combination of carbon and hydrogen, viz. by 
 passing hydrogen gas over charcoal, heated to whiteness by the passage of the electric 
 arc. 
 
 Acetylene is also produced : a. By the action of alcoholic potash on moriobromethy- 
 lene (vol. ii. 569), C 2 H 3 Br - HBr = C 2 H 2 (Sawitsch, Compt, rend. lii. 167), or on 
 bromide of monobromethylene (C 2 H 3 Br 3 ), bromacetylene, C 2 HBr, being formed at the 
 same time (Reboul, Ann. Ch. Pharm. cxxiv. 267). b. By passing the vapour of 
 monobromethylene into an ammoniacal solution of nitrate of silver, in which case a 
 precipitate is formed consisting of the silver-compound of acetylene C 2 H 2 Ag 2 (more 
 probably C 2 HAg), which, when treated with dilute hydrochloric acid, yields acetylene 
 (Miasnikoff, Ann. Ch. Pharm. cxviii. 330). c. By heating monobromethylene with 
 ethylate or amylate of sodium, the products being bromide of sodium, ethylic or amylio 
 alcohol, and acetylene. (Sawitsch, see vol. ii. p. 569.) 
 
 C 2 H 3 Br + C 5 H n NaO = NaBr + C 5 H 12 + C 2 H 2 . 
 Bromethylene. Amylate of Amylic Acetylene, 
 
 sodium. alcohol. 
 
 d. When a mixture of marsh-gas and carbonic oxide is passed througn a red-hot tube. 
 (Odling.) 
 
 CH 4 + CO = C 2 H 2 + H 2 0. 
 
 Acetylene is a colourless gas of specific gravity 0'92, having a peculiar and 
 unpleasant odour, moderately soluble in water, hot condensed by cold or pressure. It 
 burns with a very bright and smoky flame, 1 vol. acetylene consuming 2 vol. oxygen, 
 and producing 2 vol. carbonic anhydride. When mixed with chlorine, it detonates 
 almost instantly, even in diffused daylight, with separation of charcoal. 
 
 Acetylene unites with copper and with silver, forming detonating compounds, 
 which are produced on passing the gas into the ammoniacal solutions of cuprous 
 chloride and nitrate of silve" respectively. The copper- compound is red, the silver- 
 compound grey ; both are decomposed by hydrochloric acid, with separation of acetylene. 
 Acetylene mixed with air, and in presence of moisture, rapidly attacks metallic copper. 
 The gas is absorbed and the copper becomes coated with a black deposit which 
 explodes violently when heated. The formation of this substance (acetylide of copper 
 mixed probably with ciiprous oxide) is doubtless the cause of the dangerous explosions 
 which sometimes occur in the cleaning out of copper gas-mains after long use. (Crova, 
 Compt, rend. Iv. 435; J. pr. CLem. Ixxxvii. 124.) 
 
1112 ADDENDA. 
 
 Acetylene unites with nascent hydrogen, and is converted into ethylene C 2 H 4 . This 
 change is brought about by subjecting the copper-compound of acetylene to the action of 
 hydrogen evolved by the action of zinc on aqueous ammonia ; the hydrogen evolved 
 from acid liquids does not produce this reaction. 
 
 Acetylene unites, like ethylene, with bromine, sulphuric acid, and the elements of 
 water, forming with bromine the compound C 2 H 2 Br 2 , with sulphuric acid, acetyl-sul- 
 phuric acid C 2 H 2 .H 2 S0 4 , and with the elements of water, acetyl-alcohol C 2 H 2 . 
 H 2 = C 2 H 4 0. (Berthelot.) 
 
 Acetyl-sulphuric acid, C 2 H 4 S0 4 , is produced by brisk and long-continued agitation of 
 acetylene with strong sulphuric acid. If the liquid be then carefully diluted, saturated 
 with carbonate of barium, and the filtrate evaporated, acetyl-sulphate of barium is 
 obtained in crystals. (Berthelot.) 
 
 Acetylic alcohol, C 2 H 4 - C 2 H 3 .H.O, is obtained by distilling and rectifying the 
 acid liquid just mentioned, as an easily decomposible liquid resembling acetone, but 
 having an extremely pungent odour. It is somewhat more volatile than water, and is 
 separated therefrom by carbonate of potassium, but apparently not by chloride of 
 calcium. (Berthelot.) 
 
 Bromacetylene. C 2 HBr. (Eeboul, Compt. rend. Iv. 136.) Produced by the 
 action of alcoholic potash on dibromide of dibromethylene : 
 
 C 2 H > Br a .Br a - HBr - Br 2 = C 2 HBr. 
 
 Also, together with acetylene and dibromethylene, by the action of boiling alcoholic 
 potash on dibromide of monobromethylene. 
 
 C 2 H 3 Br.Br 2 - HBr = CH*Br. 
 
 Dibromethylene. 
 
 C 2 H 2 Br* - HBr = C 2 HBr. 
 
 Bromacetylene. 
 
 C 2 HBr.Br 2 - HBr _ Br 2 = C 2 H 2 . 
 
 Acetylene. 
 
 It is spontaneously inflammable, liquefies under a pressure of three atmospheres, is 
 soluble in water, and very soluble in dibromethylene, whereas acetylene is much less 
 soluble in that liquid. This property may be rendered available for the separation of 
 acetylene and bromacetylene. 
 
 It unites with bromine, forming the dibromide of bromacetylene, C 2 HBr* = 
 C 2 HBr.Br 2 . When passed into ammoniacal solution of cuprous chloride, it yields a 
 precipitate of cuprosacetylene, C 2 HCcu: 
 
 C 2 HBr + 3Cu 2 Cl =-= C 2 HCcu + CuBr + 3CuCl; 
 
 which, when treated with hydrochloric acid, yields a gas having the composition and 
 most of the properties of Berthelot's acetylene, but differing somewhat in its behaviour 
 to bromine, with which it yields the compound C 2 H 2 Br 4 , and a small quantity of C 2 HBr*. 
 
 AXiIilTXiEN'i:. C 3 H 4 . This compound, homologous with acetylene, is produced, 
 in like manner, by the action of ethylate of sodium on monobromotritylene, C 3 H 5 Br. 
 The materials are made to react in a well-cooled, sealed flask, and on opening 
 the vessel, a large quantity of gas escapes, which, when passed into an ammo- 
 niacal solution of cuprous chloride, produces a yellow precipitate. This precipitate 
 decomposed by hydrochloric acid yields pure allylene, a colourless gas, having an 
 unpleasant odour, burning with a smoky flame, and forming with mercurous salts a dark 
 grey precipitate, and with silver salts a white precipitate which detonates when heated. 
 The copper compound above mentioned burns with a reddish flame, and is decom- 
 posed with incandescence by bromine. (Sawitsch, Compt. rend. lii. 399 ; Ann. Ch. 
 Pharm. cxix. 185.) 
 
 Allylene is also produced by passing the vapour of bromotritylene into a hot con- 
 centrated alcoholic solution of potash. The gas thus evolved forms in ammoniacal 
 silver-solution, a precipitate consisting of a dark yellow compound, silver-acetylene, 
 and a heavier white compound which is silver-allylene, C 3 H 4 Ag 2 . The gas evolved 
 from this compound by the action of hydrochloric acid, forms with bromine an oily 
 liquid, which boils, with partial decomposition, between 180 and 200 C., and has 
 the composition of a mixture of C 3 H 4 Br* and C 3 H 4 Br 4 . (Morkownikoff, BulL 
 Soc. Chim. 1861, p. 90.) 
 
 C-2ESITJ1VT. Symbol, Cs. Atomic weight, 133. A metal belonging to the same 
 group of elements with lithium, sodium, potassium and rubidium. Its existence was 
 detected in 1860 by Kirchhoff and Bunsen, by help of the method of spectral analysis 
 which they introduced (see SPECTRUM, SPECTRAX ANALYSIS). The compounds of 
 caesium so closely resemble the corresponding compounds of potassium and rubidium, 
 
CJESIUM. 1113 
 
 that no difference can be perceived between them by ordinary analytical means ; but 
 in the spectrum-apparatus a few thousandths of a milligramme can easily be detected. 
 The most characteristic lines in the cesium-spectrum are two blue lines Cs a and Cs , 
 in the neighbourhood of the strontium- line, Sr 5 ; they can be clearly seen, even with 
 silicate of caesium, and the name C cesium, from casitts, sky-blue, has been chosen as 
 recalling their colour. 
 
 Caesium has not yet been found, except in company with rubidium (see ETJBTDIUM), 
 and it occurs in even still smaller quantities than the latter element. Caesium was 
 first detected in the Diirkheim mineral water, ten kilogrammes of which contain not 
 quite two milligrammes of chloride of caesium. Kreuznach water contains less, and in 
 the lepidolite of Kozena (which is the principal source of rubidium) only insignificant 
 traces of it are found. (Kirchhoff and Bun sen, Fogg. Ann. cxiii. 353; Jahresber, 
 1861, 177.) 
 
 The most abundant source of it yet discovered appears to be the lepidolite of Hebron, 
 In Maine, U.S. This mineral occurs there in large quantity in a coarsely crystalline 
 granite, associated with red and green tourmaline and albite. It has a granular, and 
 at the same time foliated crystalline structure, a pale rose to violet colour, and very 
 closely resembles the lepidolite of Penig, in Saxony, and, like that, is also associated 
 with the rare species, amblygonite. It contains rather more than 0*3 per cent, of 
 caesium, and as much rubidium as the lepidolite of Kozena. (0. D. Allen, Phil. Mag. 
 [4] xxv. 189.) 
 
 Caesium has also been found, in comparatively large quantity, in the mineral waters of 
 Baden-Baden (Bunsen), Bourbonne-les-Bains, Haute-Marne (Grandeau, Ann. Ch. 
 Phys. [3] Ixvii. 177), in the salines of Aussee, and in the lithium-mica of Zinnwald 
 (Schroetter, Wien Akad. Ber. xliv. 218). It exists in -perceptible, but generally very 
 Small, quantities, in several other minerals, as triphyline (Blake, Sill. Am. J. [2] 
 xxxiii. 274; Grrandeau), carnallite (Erdmann), petalite (Grandt.au), in the mineral 
 water of Vichy (Grandeau), in those of Topusco and Lassinja (Schneider, Wien 
 Akad. Ber. xlv. 483), and in the salines of Ebensee. (Kedtenbacher, ibid. xliv. 153.) 
 
 The separation of caesium from sodium and potassium depends upon the exceedingly 
 slight solubility in water of its chloroplatinate. In order to obtain it pure, it is preci- 
 pitated, together with chloride of potassium and chloride of rubidium, by means of 
 chloride of platinum, from the mother-liquor, freed from everything except alkaline 
 salts, obtained by the evaporation of Diirkheim water (Bunsen operated with the 
 residue of about 40,000 kilogrammes of water) ; the precipitate is boiled with a very 
 small quantity of water, allowed to settle, and the still hot solution decanted ; when 
 this operation has been repeated twenty times, the mixture of chloroplatinates of caesium 
 and rubidium which remains undissolved is reduced by heating in a stream of hydrogen, 
 and the chlorides of those metals are extracted from the residue by boiling water. To 
 separate the rubidium, the chlorides are transformed into carbonates, and the dry mix- 
 ture of salts repeatedly exhausted with absolute alcohol, in which carbonate of caesium 
 is soluble, but carbonate of rubidium insoluble. As the carbonate of caesium so obtained 
 may still contain small quantities of potassium and rubidium, it must, for com- 
 plete purification, be treated with sufficient baryta-water to render about four-fifths 
 of it caustic, evaporated in a platinum dish, and the residue extracted with the smallest 
 possible quantity of alcohol, which dissolves hydrate of caesium, but leaves the carbo- 
 nates of potassium and rubidium behind. When this operation has been repeated 
 until the product, examined in the spectrum-apparatus, no longer gives the potassium 
 and rubidium reactions, or gives them only very faintly indeed, the further treat- 
 ment of it is found not to alter its equivalent weight ; although the salt thus obtained 
 is still a mixture of the chlorides of caesium and rubidium, and not pure chloride of 
 caesium, as Bunsen at first supposed (vid. infr.). 
 
 The following process is given by Allen (loc. cit.} for the extraction of caesium from 
 the lepidolite of Hebron. Ten parts of the mineral, pulverised until it will pass 
 through a sieve of 20 holes to the linear inch, are mixed with forty parts of coarsely 
 powdered quicklime ; a quantity of water sufficient to slake the lime is next mixed 
 with as much hydrochloric acid as will convert from six to seven parts of the lime 
 into chloride of calcium ; the two mixtures are then united, and stirred vigorously 
 during the slaking, thus intimately blending the mineral with suitable proportions of 
 dry hydrate of lime and chloride of calcium. The mixture is put into Hessian 
 crucibles, and heated to redness for six or eight hours (a shorter time would probably 
 suffice). During the ignition, care must be taken to prevent the heat rising much 
 above redness, as loss would then occur by volatilisation of the alkaline chlorides, and 
 by the fusion of the mass and its consequent absorption into the crucibles. The pro- 
 duct of this operation is detached from the crucibles, and boiled with water till all but 
 a trace of the chlorides is removed. The solution thus obtained, containing chloride 
 of calcium and alkaline chlorides, is evaporated till crystals begin to form; sulphuric 
 
1114 
 
 ADDENDA. 
 
 acid is then added as long as sulphate of calcium separates, excess of acid being 
 avoided, and the whole mass is evaporated to dryness, and strongly heated, to expel free 
 hydrochloric acid. The residue is treated with water, the small quantity of sulphate 
 of calcium which passes into solution is precipitated by a carbonate of ammonium, the 
 precipitate is filtered off, and the filtrate is again evaporated to dryness and ignited. 
 In this way a mixture, of the chlorides, containing also small quantities of the sulphates, 
 of sodium, lithium, potassium, rubidium, and caesium is obtained, from which the 
 chlorides of the last two metals can be separated by treatment with bichloride of 
 platinum as directed by Bunsen. 
 
 For the separation of caesium from rubidium, Allen recommends the following 
 process. The chlorides of the two metals are converted into sulphates, and then into 
 carbonates, by precipitating with caustic baryta and saturating the solution with 
 carbonic acid. From the carbonates, the acid tartrates are prepared by adding to the 
 solution twice as much tartaric acid as is necessary to neutralise it, and these salts 
 can then be separated from each other by fractional crystallisation : acid tartrate of 
 rubidium requires for solution about eight times as much water as does acid tartrate 
 of caesium, and therefore crystallises out first, while the latter salt accumulates in the 
 mother-liquors. The salts of the two alkalis may be thus separated from each other 
 BO completely that neither shows any trace of the presence of the other when examined 
 with the spectroscope. 
 
 Pure metallic caesium has not yet been obtained, but an amalgam of caesium can 
 be easily procured by electrolysing a solution of chloride of caesium, using mercury as 
 the negative pole. Caesium-amalgam decomposes water in the cold, and when exposed 
 to the air, gets hot and covers itself with a coating of deliquescent hydrate of caesium. 
 When caesium-amalgam is connected with potassium-amalgam or with rubidium- 
 amalgam and water, so as to form a galvanic circuit, it shows itself to be more elec- 
 tropositive than either of them ; caesium is therefore the most electropositive element 
 yet known. 
 
 Bromoplatinate of Ceesium readily separates, together with the rubidium- salt, 
 when dibromide of platinum is added to a dilute solution of the chlorides of the two 
 metals. If potassium is present, the bromoplatinate of that metal is carried down 
 likewise. (Allen.) 
 
 Carbonate of C&sium, Cs 2 C0 3 + aq. Confusedly developed crystals, which give 
 an anhydrous sandy powder when heated. Dissolves in 9'1 pts. absolute alcohol at 
 19 C., and in 5 pts. at 78'4 C. ; very caustic; deliquesces in the air and gradually 
 becomes converted into acid carbonate ; dissolves in water in nearly all proportions 
 with the aid of heat. 
 
 Acid carbonate of C&sium, CsHCO 9 . Tolerably well-formed, but not measur- 
 able prismatic crystals, permanent in the air, of a glassy lustre. Reacts hardly alkaline ; 
 by ignition it is easily changed into the neutral salt. 
 
 Chloride of Cesium, CsCl. Crystallises in cubes, which deliquesce in the air 
 like chloride of lithium, and can thereby be distinguished from chloride of potassium 
 or of rubidium. When gently ignited, chloride of caesium easily melts ; it is somewhat 
 volatile, and in the air easily becomes somewhat alkaline. (Bunsen.) According to 
 Johnson and Allen pure chloride of caesium is not deliquescent. 
 
 Chloroplatinate of Ccesium, CsClPtCl 8 . Bright yellow sandy powder, com- 
 posed of shining, transparent, microscopic regular octahedrons. It is more difficultly 
 soluble than the chloroplatinate of either potassium or rubidium ; the following table 
 gives the solubility in 100 pts. water of the three salts, as determined by Bunsen, the 
 
 Temperature. 
 
 Potassium-salt. 
 
 Rubidium-salt. 
 
 Caesium-salt. 
 
 0C. 
 
 0-74 
 
 0184 
 
 0-024 
 
 10 
 
 0-90 
 
 0-154 
 
 0-050 
 
 20 
 
 1-12 
 
 0141 
 
 0-079 
 
 30 
 
 1-41 
 
 0-145 
 
 0-110 
 
 40 
 
 176 
 
 0-166 
 
 0-142 
 
 50 
 
 2-17 
 
 0-203 
 
 0-177 
 
 60 
 
 2-64 
 
 0-258 
 
 0-213 
 
 70 
 
 3-19 
 
 0-329 
 
 0-251 
 
 80 
 
 3-79 
 
 0-417 
 
 0-291 
 
 90 
 
 4-45 
 
 0-521 
 
 0-332 
 
 100 
 
 6-18 
 
 0-634 
 
 0-377 
 
CJESIUM; 1115 
 
 caesium-salts having been purified by the first process, and 'therefore still' containing a 
 little rubidium. 
 
 Hydrate of C&sium, CsHO + aq. Confusedly crystallised, deliquescent, exceed- 
 ingly caustic. At a red heat it does not become anhydrous ; it attacks platinum, is en- 
 tirely volatile when heated on a platinum wire, and is easily soluble in alcohol. 
 
 Nitrate of C cesium, CsNO 3 . Contains no water of crystallisation, is isomorphous 
 with nitrate of rubidium and not with nitrate of potassium. The crystals are hexagonal 
 prisms combined with the hexagonal pyramid P : P in the terminal edges = 142 56' ; 
 in the lateral edges = 78 58'. Rates of axes, 1 : c = 1 : 07135. 
 
 P . ooP . P2 .... ooP2 . OP . | P. 
 
 The salt has a cooling saline taste, like that of saltpetre, and is soluble in ten times 
 its weight of water at 3 C. (B u n s e n. ) 
 
 Pier ate of Ccssium resembles the corresponding potassium-salt. It cannot be 
 separated from picrate of rubidium by crystallisation. (Allen.) 
 
 Sulphate of Ccesium, Cs 2 S0 4 , forms anhydrous, ill-defined, hard crystals, grouped 
 together in bunches, and permanent in the air. One part of the salt dissolves in 0'63 
 pts. of water at 2 C. (1 pt. of sulphate of potassium dissolves in 12 '5 pts. of water 
 at the same temperature.) 
 
 cobalt, 
 
 responding potassium- and ammonium-compounds. 
 
 lowing surfaces : OP . ooP . + P . [P oo] . + 2P oo . ooP2. Sulphate of caesium forms, 
 
 with sulphate of aluminium, an alum crystallising in regular octahedrons of a glassy 
 
 lustre. (Bunsen, Ann. Ch. Pharm. cxix. 111.) 
 
 Acidtartrate of C&sium, C 4 H 5 Cs0 6 . Colourless, transparent, flattened prisms, 
 which do not diminish in weight when pulverised and dried at 100. One part of this 
 salt dissolves in 1-02 pts. of boiling water, or in 10*32 pts. of water at 25 C. (Allen.) 
 The neutral tartrate is very deliquescent. (Bunsen.) 
 
 Atomic weight of Casium. The atomic weight of caesium has been determined by 
 the analysis of its chloride. This salt, purified from chloride of rubidium by means 
 of chloride of platinum in the manner already described, was found by Bunsen to 
 contain : 
 
 Chlorine. Caesium. 
 
 After the 1st purification, .... 22-334 77'666 
 
 2nd .... 22-334 77'666 
 
 3rd .... 22-316 77'684 
 
 whence he deduced 123-4 for the atomic weight of caesium. Subsequent experiments 
 by Johnson and Allen (Phil. Mag. [4] xxv. 196) have shown that the chloride of 
 caesium used for these determinations still contained chloride of rubidium, and that the 
 atomic weight calculated from them is consequently too low. Their analyses of 
 chloride of caesium, prepared from the acid tartrate purified by concentrating its solu- 
 tion and recrystallisation, gave the following results : 
 
 Chlorine. Caesium. 
 
 I. 21-044 78-956 
 
 II. 21-031 78-969 
 
 III. 21-043 78-957 
 
 IV. 21-063 78-937 
 
 Bunsen has since published new determinations (Pogg. Ann. cxix. 1) which agree very 
 closely with these. The chloride of caesium used for them was prepared by the follow- 
 ing process, from a mixture of the chlorides of caesium and rubidium which had been 
 previously completely freed from potassium, sodium, and lithium. The chlorides were 
 first converted into carbonates, and then a little more tartaric acid was added to the 
 solution than was needed to convert the caesium into neutral tartrate and the rubidium 
 into the acid salt (the quantity of acid requisite being deduced from a preliminary 
 determination of the amount of chlorine in the mixed chlorides). The liquid was next 
 evaporated to dryness, and the powdered saline mass exposed to moist air in a funnel 
 ptopped with a small filter. In this way a solution of the very deliquescent tartrate of 
 caesium, was obtained, while the acid tartrate of rubidium remained as a solid salt in 
 the funnel. The tartrate of caesium was converted into chloride, precipitated with 
 bichloride of platinum, the precipitate washed and decomposed by heating in a stream 
 of hydrogen, and this process was repeated until the proportion of chlorine in the 
 
1116 ADDENDA. 
 
 resulting chloride of caesium did not alter any longer. The product so prepared 
 gave 
 
 Chlorine. Caesium. 
 
 After the 4th purification, .... 21-057 78-943 
 
 5th .... 21-045 78-955 
 
 6th .... 21-052 78-948 
 
 Taking Ag = 107-94 and Cl = 35-46 {Stas), the mean of Johnson and Allen's experi- 
 ments gives 133-03 for the atomic weight of caesium, while the mean of Bunsen's most 
 recent experiments gives 132-99, so that we may take Cs = 133*0 as being very near 
 the truth. 
 
 On the spectrum of caesium, see Johnson and Allen (Phil. Mag. [4] xxv. 199), and 
 Bunsen (Pogg. Ann, cxir. 6). GK C. F. 
 
INDEX 
 
 TO 
 
 THE FIRST VOLUME. 
 
 PAGE 
 
 Abichite. ..... . 1 
 
 Abieticacid 
 
 Abietin 
 
 Abrazite 
 
 Absinthin 2 
 
 Absorption of gases (s. Gases). 
 
 Acacin 
 
 Acadiolite 
 
 Acajou 
 
 Acaro'id resin 
 
 Acechloride of Platinum (s. Acetone, de- 
 compositions of). 
 
 Acediamine 
 
 Acephosgenic and Acephossic acids . 3 
 
 Acetal 
 
 Chloracetals 4 
 
 Acetamide ...... 5 
 
 Chloracetamide .... 6 
 
 Diacetamide 7 
 
 Ethylacetamide (s. Ethylamine). 
 
 Mercuracetamide .... 
 Phenylacetamide (s. Phenylamine). 
 
 Acetene 
 
 Acetic acid 
 
 Acetates 12 
 
 of Aluminium 13 
 
 Ammonium 
 
 Barium 
 
 Bismuth 
 
 Cadmium 
 
 Calcium 
 
 Cerium ...,. 
 
 Chromium ..... 14 
 
 Cobalt 
 
 Copper 
 
 Iron . ..... 
 
 Lead 16 
 
 Lithium 17 
 
 Manganese 
 
 Mercury ..... 
 
 Nickel 
 
 Potassium 
 
 Silver 18 
 
 Sodium ~ 
 
 Strontium . . , . . . 
 
 Acetates of Tin .... 
 
 Uranium ... 
 
 Yttrium . . 
 
 Zinc .... 
 Acetic acid, substitution-products of 
 Acetic anhydride .... 
 Aceto-benzoic anhydride 
 Aceto- cinnamic anhydride . . 
 Aceto-cuminic anhydride . . 
 Acetp-salicylic anhydride 
 Acetic ethers 
 
 1. Monatomic: 
 
 Acetate of allyl . 
 
 Amyl . . . 
 Benzyl 
 Ethyl . 
 Chlorinated acetates of Ethyl 
 
 Methyl 
 
 Chlorinated acetates of Methyl 
 Acetates of Octyl 
 
 Phenyl . 
 
 Tetryl 
 
 Trityl 
 
 2. Diatomic: 
 
 Acetates of ethylene, amylene, 
 benzylene, tetrylene, and tri- 
 tylene 
 
 3. Triatomic: Acetins 
 
 Monacetin 
 
 Diacetin 
 
 Triacetin 
 
 Acetochlorhydrin . 
 
 Acetodichlorhydrin 
 
 Diacetochlorhydrin 
 
 Acetochlorbromhydrin 
 
 Acetite 
 
 Acetometer 
 
 Acetone 
 
 Substitution -products of Acetone : 
 
 Chloracetones 
 
 Bromacetone 
 
 lodacetone . 
 
 Methylacetone 
 
 Ethylacetone 
 Acetones or Ketonea 
 
 PAGE 
 18 
 
 19 
 
 21 
 
 22 
 23 
 
 24 
 
 25 
 
 26 
 
 29 
 31 
 
1118 
 
 INDEX TO 
 
 PAGE 
 
 Acetonine 32 
 
 Acetonitrile . . . . . . 
 
 Acetonyl 33 
 
 Ac.itosyl 
 
 Acetoxyl 
 
 Aceture'id 
 
 Acetyl 
 
 Bromide of Acetyl ... 34 
 
 Chloride of Acetyl ... 35 
 
 Hydride of Acetyl 
 
 Iodide of Acetyl 
 
 Peroxide of Acetyl 
 
 Acetylous acid . ... 36 
 Acliillea millefolium 
 Achilleic acid . 
 
 Achillein 
 
 Achirue (s. Dioptase). 
 
 Achmite or Acmite 
 
 Adiroi'te. Achtarandite ... 37 
 Acibromides, Acichlorides, &c. (s. Oxy- 
 
 bromides, Oxyehlorides, &c.) . . 
 
 Aciculite .... . . 
 
 Acidimetry 
 
 Acids .39 
 
 Aconitic acid .54 
 
 Aconitates (metallic) 
 
 Aconitate of ethyl . . 55 
 
 Aconitanilic acid 
 
 Aconitodianil . 
 
 AconiUnilide . . 
 Aconitine ... 
 
 Aconityl . . . . 56 
 
 Acrene ..... . . 
 
 Acroletn . ; 
 
 Acrolein-ammonia .... 57 
 
 Acrolein withacidsulphiteofsodium 
 
 Hydrochlorate of acrolein . 
 
 Metacrplein . .... 
 Acrylic acid . . . . . . 
 
 Acrylates 58 
 
 Actinolite (s. Hornblende). 
 Adamant (a, Diamond). 
 
 Adapter or Adopter . . 
 Adhesion (s. Cohesion). 
 Adhesive slate (s. Slate). 
 Adiaphanous spar (s. Gehlenite and Saus- 
 surite). 
 
 Adinole 
 
 Adipic acid 
 
 Adipates 
 
 Adipocere 59 
 
 Adularia. ^Edelforsite .... 
 
 Aegirin, or Aegyrin . . . 
 Aerated Waters (s. Carbonic Acid and 
 
 Water) 
 
 Aerolite (s. Meteorite) .... 
 
 Aerugo (s. Acetate of Copper ; Verdigris) 
 
 Aeschynite ... . . . 
 
 Aesculetin, or Esculetin ... 
 
 Aesculic acid 
 
 Aesculin, or Esculin . . 60 
 
 Aethal.(s. Cetyl) _ 
 
 Aether, Aethy], .&c (s. Ether, Ethyl, 
 
 &c.) . , __ 
 
 Aethiops 
 
 Aethokirrin 
 
 Affinity (s. Chemical Affinity) . . 
 
 Aftonite (s. Aphtonite) .... 
 
 Agalmatclite 
 
 AgaphLte. Agar-Agar . . . .61 
 
 Agiiricin (s. Amanitin) .... 
 
 Agaricus 
 
 Agaricus Mineralis . ... 62 
 
 Agate . . . . . . . 
 
 PAGE 
 
 Agedoi'l. Agnesite . 62 
 Agrostemmine ..... 
 
 Aikinite. Air . . . .63 
 
 Ajuga reptans .... 
 
 Akanticon. Akcethin (s. Acetone) 
 Akmite (s. Achmite) . . . 
 Akontite. ..... 
 
 Alabandin (s. Manganese-glance) 
 
 Alabaster 
 
 Alalite (s. Diopside) 
 
 Alanine ..... 
 
 Alantin (s. Inulin) ... 64 
 
 Albene 
 
 Albin (s. Apophyllite) . 
 
 Albite (s. Felspar) 
 
 Album grajcum ..... 
 
 Albumin 65 
 
 Albuminates 68 
 
 Albumin, vegetable .... 69 
 Albuminin . , . . . .70 
 
 Albuminoids 
 
 Albuminose 72 
 
 Alcarrazas ...... 
 
 Alchemilla vulgaris .... 
 
 Alcohol ....... 
 
 Alcoholates 80 
 
 Alcohol bases 81 
 
 Alcoholometry 
 
 Alcohol- radicles 96 
 
 Alcohols . . . . . 
 
 Monatomic alcohols 
 
 Diatomic alcohols: Glycols . . . 
 
 Triatomic alcohols : Glycerins 
 
 Alcohols not included in the prece- 
 ding groups . 
 Aldehyde . 
 
 Aldehydates 
 
 Aldehyde-ammonia 
 
 Compound of aldehyde with acetic 
 anhydride ..... 
 
 Modifications of aldehyde : Elal- 
 dehyde, metaldehyde/&c. . 
 
 Aldehyde-resin .... 
 
 Aldehydes 
 
 Aldide 
 
 Alembic .... . . 
 
 Alembrjoth-salt 
 
 Alexandrite (s Chrysoberyl) 
 Algaroth-powder ..... 
 Algerite ... , 
 
 Alimentary Substances (s.- Nutrition) . 
 
 Alismin 
 
 Alixia-camphor ..... 
 Alizaric acid . . . . 
 Alizarin. Alizite (s. Pimelite) 
 Alkali 
 
 97 
 
 102 
 103 
 
 104 
 105 
 107 
 
 108 
 109 
 
 110 
 112 
 113 
 
 115 
 
 Alkalimetry ...... 117 
 
 Alkaloids . . . . . .120 
 
 Detection of, in chemico-legal in- 
 
 vestigations 
 Alkanet 
 Alkargen and Alkarsjn (s. Ar enic 
 
 radicles Organic, p. 403) . 
 Allagite. Allaite . 
 Allanite (s. Orthite) 
 Allan toic and Amaiotic liquids 
 Allantoin ... ... 
 
 Allanturic acid . 
 Allemontite .... 
 
 Allituric acid . ... 
 
 Allium sativum . . 
 Allochroi'te. Allogonite . 
 Allomorphite 
 Allophane 
 
 125 
 
 128 
 
 130 
 132 
 
THE FIRST VOLUME. 
 
 1119 
 
 PAGE 
 
 Allophanic acid .... 132 
 
 Allophanates (metallic) . 
 
 Allophanic ethers . . . 133 
 Allophanate of Amyl 
 Ethyl 
 
 Ethylene . 134 
 
 Glycervl 
 
 Methyl . 
 
 Eugenic acid 
 
 Allotropy (s. Isomerism) . 135 
 
 Al'oxan ........ 
 
 Alloxanic acid .... 137 
 
 Alloxantin 138 
 
 Tetramethyl-alloxantin . . . 140 
 
 Alloys (s. Metals) 
 
 Alluaudite (s. Triphyline) ... 
 
 Allyl. Allyl-alcohol . 
 
 Allyl: Bromides of . . .141 
 
 Chlorides of . . . 142 
 
 Hydride of . 
 
 Iodides of . 
 
 Oxide of . 
 
 Oxygen-salts of . . .143 
 
 Sulphide of: Oil of Garlic . 
 
 Metallic compounds of Sulphide 
 
 of Allyl 144 
 
 Allyl and hydrogen. Sulphide of Allyl- 
 mercaptan . . . . . .145 
 
 Allyl-sulphocynate of (s. Sulphocyanic 
 
 ethers) " 
 
 Allyl-sulphocarbamic acid : Sulphosin- 
 
 apic acid ...... 
 
 Allyl-sulphocarbonic, or Allyl-xanthic 
 acid . . . . . .146 
 
 Allyl -urea (s. Carbamide, p 754) . . 
 
 Allylamine ...... 
 
 Diallylamine ..... 
 
 Dibromallylamine .... 
 
 Ethyl -dibromallylamine . . 
 
 Triallylamine .... 
 
 Tetrallylium 
 
 Tetrallylarsonium 
 
 Allylene 147 
 
 * Chloride. Acetate . 
 
 Almagrerite. Almandine ... 
 
 Almonds, oil of 
 
 Aloeretic acid (s. Aloetic acid p. 148) . 
 
 Aloes 
 
 Aloetic acid 148 
 
 Aloin . . . 
 
 Aloisol ....... 
 
 Alouchi or Aluchi-resin .... 
 
 Alphene, sulphide of (s. Sulphocyanide of 
 
 ammonium) ..... 149 
 
 Alstonite 
 
 Altaite 
 
 Althein 
 
 Althionic acid ..... 
 
 Aludels 
 
 Alum (s. Sulphates) .... 
 
 Alumina (s. Oxide of aluminium, p. 157) 
 
 Aluminates 
 
 Aluminite ...... 
 
 Aluminium .... . 
 
 Preparation from the chloride . 150 
 
 Cryolite . 151 
 
 Reduction by hydrogen or carbon . 
 Preparation by electrolysis . .152 
 
 Properties 153 
 
 Uses 154 
 
 General characters and reactions of 
 
 aluminium compounds . . 
 Quantitative estimation of alumi- 
 nium- . . . . 155 
 
 PAGE; 
 
 Aluminium, alloys of . . .155 
 
 Arsenide . . . . 156 
 
 Boride . 
 
 Chloride . . . . 
 
 Fluoride . . . . 157 
 
 Iodide . 
 
 Oxide : Alumina 
 
 Hydrates of, or of Alumina . 159 
 
 Aluminates .... 160 
 
 Oxygen-salts of aluminium 
 
 Phosphide of aluminium 
 
 Silicide of aluminium 
 
 Selenide of aluminium 
 
 Sulphide of aluminium . 
 
 Alumo-cak'ite . . . 
 
 Alum -earth .... 
 
 Alum -slate . . . ' . 
 
 Alunite or alum-stone. Alunogen 161 
 
 Amalgam 
 
 Amalgamation 
 
 Amalic acid . 
 
 Amanitine 
 
 Amarine 
 
 Amarine-salts . . 162 
 
 Diethylamarine 
 
 Trinitramarine 
 
 Amarone ...... 
 
 Amaryl 163 
 
 Amarythrine 
 
 Amasatin 
 
 Amausite 
 
 Amazon-stone . . . . . 
 
 Amber . 
 
 Ambergris 164 
 
 Amblygonite 
 
 Ambrein . 165 
 
 Amethanes 
 
 Amethyst ...... 
 
 Amianthoi'd (s. Hornblende) . . 
 
 Amianthus (s. Asbestos, p. 415). 
 
 Amic acids ...... 
 
 Amides 168 
 
 Monamides 169 
 
 Diamides 172 
 
 Triamides 173 
 
 Amines : 
 
 Monamines - 
 
 Diamines 176 
 
 Triamines 177 
 
 Tetramines and Pentamines 
 
 Phosphines, Arsines, Stibines 178 
 
 Alkalarnides : 
 
 Monalkalamides . k 
 
 Dialkalamides . . . 180 
 
 Trialkalamides . . 181 
 
 Amidin (s. Starch). 
 Amidogen (s. Amides, p. 168). 
 Amidone (s Starch). 
 Ammelide, Ammeline (s. Melam). 
 
 Ammiolite 182 
 
 Ammonia . .... 
 
 History, Sources, Formation . . 
 Preparation, Properties, Decomposi 
 
 tions 183 
 
 Combinations : 
 
 1 . W i th AV at er : A queous Ammonia . 1 84 
 
 2. With alcohol . . . .187 
 
 3. With metallic salts ... 
 
 4. With acids 
 
 5. With polybasic anhydrides . . 
 Ammoniacal salts, or Ammonium-salts . 187 
 
 Reactions of Ammonium salts . . 
 Separation and Estimation of Am- 
 monium . . _ 
 
1120 
 
 INDEX TO 
 
 PAGE 
 
 Ammoniacal salts : Acetates . . .190 
 
 Carbonates . . 
 
 Chloride 191 
 
 Hydrate 192 
 
 Nitrate ..,...- 
 
 Oxalates 
 
 Phosphates 193 
 
 Sulphates ..... 
 
 Sulphides 
 
 Ammonium ...... 194 
 
 Ammonium-amalgam (p. 186). 
 
 Ammonium-bases 
 
 Polyammonium -bases . . .196 
 
 Ammonium-bases containing metals 198 
 Amniotic liquid (p. 128). 
 
 Amoibite ...... 199 
 
 Amorphism 
 
 Ampelicacid 201 
 
 Ampelin 
 
 Amphibole (s. Hornblende). 
 
 Amphid salts 
 
 Amphigene (s. Leucite) .... 
 
 Amphilogite (s. Didrimite) 
 
 Amygdalic acid 
 
 Amygdalm . 
 Amyl 
 
 Bromide of Amyl 
 
 Chloride . 
 
 Cyanide . 
 
 Hydrate of Amyl 
 
 Amylic alcohol 
 
 Hydride of Amyl 
 
 lo'lide of Amyl 
 
 Oxide of Emyl : Amylic ether 
 
 Oxide of Amvl and Ethyl 
 
 Methyl . 
 Potassium 
 Sodium . 
 Sulphides of Amyl : 
 Protosulphide and Disulphide 
 Sulphide of Amyl and Hydrogen : 
 
 Amyl mercaptan 
 
 Sulphide of Carbonyl, Amyl, and 
 Hydrogen : Amyl-xanthic acid 
 
 202 
 203 
 
 204 
 205 
 
 206 
 
 Dioxysulpl 
 Telluride of Amyl 
 Amylamines : 
 
 Amylamine 
 
 Salts of Amylamine . . . 207 
 
 Amylsulphocarbonate of Amylium 
 
 Diamylamine 
 
 Triamylamine .... 
 
 Tetramylium 
 
 Amylates (p. 205). 
 
 Amylene ...... 208 
 
 " Acetate of Amylene . 
 
 Bromide 
 
 Hydrate 
 
 Nitrylide 
 
 Oxide 209 
 
 Amylene with Sulphur and Chlo- 
 rine: 
 
 Dichlorosulphide of Amylene . 
 
 Disulphocbloride of Amylene . 
 Amylene with Sulphur and Oxygen: 
 
 Disulphoxide of amylene . . 
 
 Anacardic acid 
 
 Analcime 210 
 
 Analysis, Inorganic : 
 
 Preliminary examination . . 213 
 Solution of solid bodies . 
 
 Qualitative analysis of solutions . 216 
 
 Examination for metals ... 
 
 Examination for acida . . . 222 
 
 PAGB 
 
 Analysis, Inorganic : 
 
 Quantitative analysis: 
 
 Indirect method .... 
 Analysis, Organic 
 
 I. Elemental or ultimate analysis : 
 Qualitative analysis 
 Quantitative analysis: 
 
 Apparatus and materials . 
 Preparation of the substance for 
 
 analysis 
 
 Estimation of Carbon and Hydrogen : 
 
 In solids not containing nitrogen 232 
 
 In liquids 
 
 Modifications in the case of 
 bodies containing nitrogen . 
 
 Modifications in the case of bo- 
 dies containing sulphur, chlo- 
 rine,bromine,iodine, or metals 
 
 Amount of error in the estima- 
 tion of carbon and hydrogen 
 Estimation of Oxygen . 
 Estimation of Nitrogen : 
 
 Liebig's comparative method . 
 
 Bunaen's comparative method 
 
 Dumas's absolute method . 
 
 Simpson's 
 
 Will and Varrentrapp's 
 Estimation of Chlorine 
 Estimation of Sulphur 
 Estimation of Phosphorus 
 Determination of the chemica 
 formula of an organic compound 
 
 II. Proximate organic analysis . 
 Examination of animal substances 
 
 Zoochemical analysis . 
 Analysis (volumetric) of Liquids and 
 Solids : 
 
 I. Apparatus 
 
 II. Preparation of Standard solutions 
 
 III. Description of Volumetric pro- 
 
 224 
 
 225 
 
 226 
 231 
 
 236 
 237 
 
 238 
 
 239 
 240 
 242 
 243 
 244 
 246 
 247 
 
 248 
 249 
 
 250 
 
 254 
 
 257 
 
 1. Analysis by Precipitation . . 259 
 
 2. Analysis by Saturation . . 261 
 Acidiinetry and Alkalimetry . 262 
 
 3. Analysis "by Oxidation and Re- 
 
 duction ..... 
 
 a. With Permanganic acid . . 263 
 
 b. With Iodine .... 264 
 Analysis (Volumetric) of Gases . . 268 
 
 Bunsen's apparatus 
 
 Williamson and Russell's apparatus 274 
 
 Regnault and Reiset's apparatus . 275 
 
 Frankland and Ward's apparatus . 279 
 Estimation of gases directly or by 
 
 absorption 281 
 
 Estimation of gases indirectly or by 
 
 combustion .... 284 
 
 Analysis, Zoochemical (p. 250). 
 
 Anamirtin 289 
 
 Anamirtic acid .... 
 
 Ananas, oil of 
 
 Anatase 
 
 Anatta (s. Annotto). 
 
 Anauxite 
 
 Anchoic acid 
 
 Anchoates 290 
 
 Anchusin or Anchusic acid . 
 
 Andalusite 201 
 
 Andaquies wax 
 
 Andesin . 
 
 Andreolite (s. Harmotome). 
 
 Anemonin ...... 
 
 Anemonic acid .... 
 
 Angelica balsam 292 
 
THE FIRST VOLUME. 
 
 1121 
 
 299 
 
 300 
 301 
 302 
 303 
 
 304 
 
 Angelic acid 292 
 
 Angelates 293 
 
 Angelic anhydride .... 
 
 Angelicin . ... . . 
 
 Anglarite. Anglesito .... 
 
 Angusturine 
 
 Anhydrides 
 
 Anhydrite 295 
 
 Anil 
 
 Anilamic acid (s. Phenylamic acid) . 
 Anilides (s. Phenylamides). 
 Aniline (s. Phenylamine). 
 
 Anime resin 
 
 Animine 296 
 
 Anion ....... 
 
 Anisal (s. Hydride of Anisyl, p. 307)". 
 
 Anisamic acid 
 
 Anisamide 297 
 
 Anisamines 
 
 Anisanilide (s. Phenylanisamide) 
 
 Anise, oil of 
 
 Oil of anise and oil of fennel 
 Oil of tarragon . 
 
 Bitter fennel 
 Anishydramide 
 Anisic acid . 
 
 Anisates (metallic) 
 Anisic ethers . 
 Bromanisic acid 
 Chloranisic acid 
 Nitranisic acid 
 Trinitranisic acid 
 Sulphanisic acid 
 Anisic alcohol 
 Anisic anhydride . 
 Anisidine 
 
 Nitranisidine . 
 Dinitranisidine 
 Anisine (s. Anishydramide). 
 Anisoic acid . 
 Anisoin (s. Anise, oil of). 
 
 Anisol 305 
 
 Chlor- and Brom-anisol 
 .Nitranisol . . . 
 
 Di- and tri-nitranisol . . . 306 
 Anisulmin . . 
 Anisuric acid . . . 
 Anisyl .... 
 Bromide of Anisyl . 
 Chloride . 
 
 Hydride . .... 307 
 
 Ankerite Annabergite 
 Annealing 
 Annotto 
 
 Anode 308 
 
 Anorthite 
 
 Anotto (s. Annotto). 
 
 Anoxoluin 
 
 Anthokirrin 309 
 
 Anthokyan or Cyanin .... 
 
 Antholeucin 
 
 Anthophyllite (s. Hornblende). 
 
 Anthosiderite 
 
 Anthoxanthin 
 
 Anthracene or Anthracin (s. Para- 
 naphthalin). 
 
 Anthracite 
 
 Anthracolite or Anthraconite 
 
 Anthracoxene 
 
 Anthranilic acid (s. Phenylcarbamic 
 Acid, p. 751). 
 
 Anthropin 310 
 
 Antiarin 
 VOL. I. 
 
 PAGE 
 
 Antiar resin 310 
 
 Antichlor 
 
 Antichloristic theor}- (s. Chlorine) . 
 Lntigorite . . . . . .311 
 
 Antimonates (s. Antimony, Oxides of, 
 
 p. 325). 
 Antimonial Copper (s. Copper, Sulphides 
 
 of). 
 
 Antimonial copper glance . . 
 
 Antimonial crocus (s. Antimony, Oxy- 
 
 sulphide of ). 
 
 Antimonial lead-ores (s. Lead, Sul- 
 phides of). 
 Antimonial nickel and antimonial 
 silver, (s. Antimony, Alloys of, 
 p. 316). 
 
 Antimonial sulphide of silver (s. Silver, 
 Sulphide of). 
 
 Antimonite 
 
 Antimonites (s. Antimony, Oxides of, 
 p. 323). 
 
 Antimony 
 
 History, Sources, Preparation . 
 
 Purification 313 
 
 Tests for impurities . . .314 
 Properties . . . . .315 
 Amorphous antimony ... 
 Antimony, Alloys of . . . .316 
 
 Antimony Bloom 317 
 
 Antimony, Bromide of . . . . 
 Antimony, Chlorides of* 
 
 Trichloride . . . . . 
 
 Pentachloride 318 
 
 Antimony, Detection and estimation of: 
 
 1. Blowpipe reactions ... 
 
 2. Liquid reactions . . . .319 
 
 3. Quantitative estimation . . . 320 
 Atomic weight of antimony . . 321 
 Valuation of antimony ores . . 
 
 4. Separation of antimony from other 
 
 metals 
 
 Antimony, Fluoride of . . . . 322 
 Antimony-glass (s. Antimony, Oxj^sul- 
 
 pliide of, p. 328). 
 
 Antimony, Hydride of . . . . 
 Antimony, Ores of (pp. 311, 321). 
 Antimony, Oxides of; 
 
 Trioxide or Antimonious oxide . 323 
 Tetroxide or Antimonoso-antimonic 
 
 oxide 324 
 
 Pentoxide, Antimonic oxide, or an- 
 hydride 
 
 Antimonates and Metantimonates . 325 
 
 Antimony, Oxychloride of . . 327 
 
 Antimony, Oxyidide of . . . 328 
 
 Antimony, Oxy sulphide of 
 
 Antimony, Selenide of . 
 
 Antimony, Sulphides of . . 329 
 
 Trisulphide, Antimonious sulphide, 
 
 or Sulphantimonious Anhydride 
 
 1. Crystallised ... 
 
 2. Amorphous: Mineral Kermes 330 
 Hydrated trisulphide . . 331 
 
 Sulphantimonites . . 334 
 Pentasulphide of antimony, 
 Antimonic sulphide or Sul- 
 
 phantimonic anhydride 
 
 Sulphantimonates . . 335 
 
 Antimony, Sulphochloride of . . 338 
 
 Antimony, Sulphiodide of . . 
 
 Antimony-radicles, Organic . . 339 
 
 Antimonides of Amyl or Stibamyls 
 
 Stibdiamyl 340 
 
 Stib-triamyl or Triamyl-stibine . 
 C 
 
1122 
 
 INDEX TO 
 
 Antimony-radicles, Organic ; 
 
 Antimonides of Ethyl or Stibethyla : 
 
 Stibtriethyl or Triethylstibino 
 
 Stibethylium or Tetrethylstibo- 
 
 nium ..... 
 Antimonides of Methyl or Stib- 
 methyls .... 
 
 Stibtrimethyl or Triethylstibine 
 
 Stibpentamethyl 
 
 Stibmethylium or Tetramethyl 
 stibonium 
 
 Stibtrimethyltriethylium . 
 
 Stibmethyltriethylium 
 Antiphlogistic theory (s. Combustion) 
 Antirrhin (s. Anthokirrin, p. 309). 
 Antirrhinic acid .... 
 Antiseptics . . 
 
 Antitartaric acid 
 
 Antrimolite 
 
 Ants, oil of 
 
 Antyrrhinic acid 
 
 Anylamide (s. Salicylamide). 
 
 Apatelite 
 
 Apatite 
 
 Apatoid 
 
 Apelaic acid (s. Azelaic Acid). 
 Aphanesite (s. Abichite, p. 1). 
 Aphanite (s. Diorite) 
 Aphlogistic lamp (p. 74). 
 
 Aphrite 
 
 Aphrizite (s. Tourmaline). 
 
 Aphrodite ... . . 
 
 Aphronitrum 
 
 Aphrosiderite 
 
 Aphtalose (s. Arcanite). 
 
 Aphtonite 
 
 Apiin 
 
 Apios tuberosa 
 
 Apirin or Apyrin 
 
 Apjohnite. Aplite . 
 Aplome (s. Garnet). 
 Apoglucic acid (s. Glucic Acid). 
 Apocrenic acid (s. Humic Acid). 
 
 Apophyllic acid 
 
 Apophyllite 
 
 Aporetin 
 
 Aposepidin 
 
 Apothem 
 
 Apples . 
 
 Apple-tree 
 
 Apple-oil (artificial) . 
 Apyrin (s. Apirin, p. 350). 
 Apyrite (s. Tourmaline). 
 
 Aqua fortis 
 
 Aquamarine (s. Bjryl, p. 581). 
 Aqua-regia or regis . . . , 
 
 Aqua vitse 
 
 Aquila alba, mitigata, caelestis, mercurii 
 
 Arabic (gum) 
 
 Arabin 
 
 Arachidic acid 
 
 Arachidates 
 
 Arachin ...... 
 
 Arachis hypogaea . 
 
 Arachyl 
 
 Araeometer (s. Hydrometer)' 
 Araeoxene ...... 
 
 Arbol-a-brea resin . 
 
 Amyrin, Bre'idin, Brei'n, Bryoi'din . 
 Arbor Dianae, Martis, Saturni. &c. 
 
 Arbutin 
 
 Arcanite (s. Glaserite). 
 
 Archil ....... 
 
 Arctizite (s. Wernerite). 
 Arctostaphylos Uva Ursi 
 
 PAGE 
 
 341 
 
 344 
 
 345 
 
 347 
 
 348 
 
 349 
 
 349 
 
 350 
 
 351 
 352 
 
 353 
 
 354 
 
 355 
 
 806 
 
 PACK 
 
 Arctuvin . . . . . . 356 
 
 Areca nuts ..... . 
 
 Arendalite (s. Epidote). 
 
 Arethase 
 
 Arfwedsonite . . . . . . 
 
 ArgalorArgol 
 
 Argentan 
 
 Argentammonium 
 
 Argentine 
 
 Argentine flowers of antimony . . 
 
 Argentite (s. Silver-glance). 
 
 Argillaceous earth (a. Alumina and Clay). 
 
 Argyrites. Argyrose .... 
 
 Arfcrne . 357 
 
 Aristolochia Clematitis 
 
 Serpentaria ... 
 
 Arkansite (s. Brookite, p. 681) . . 
 
 Arki (s. Arsa). 
 
 Arkose . 
 
 Armenian stone 
 
 Arnica, oil of . 
 
 Arnicine . . 358 
 
 Arpidelite. Arquerite 
 
 Arrack . 
 
 Arragonite . . . 
 
 Arrow-root . . 359 
 
 Arsa 
 
 Arsenic : 
 
 History 
 
 Occurrence, preparation, properties . 360 
 Detection and estimation : 
 
 Reactions in the dry way . . 361 
 Reactions in the wet way . . 
 . Of arsenions compounds . 
 /9. Of arsenic compounds . . 363 
 Detection of arsenic in cases of 
 
 poisoning 3C5 
 
 Quantitative estimation of arsenic . 367 
 Atomic weight of arsenic . . 368 
 Separation from other elements . 
 Valuation of arsenic ores . . 370 
 
 Arsenic, Alloys of 
 
 Arsenic, Bromide of . 371 
 
 Arsenic, Chloride of 
 
 Ammonio-chlonde 
 
 Arsenic, Fluoride of 
 
 Arsenic, Hydride of 
 
 Arsenic, Dihydride 
 
 Arsenic, Trihydride, Arsenetted Hydrogen, 
 
 or Arsenamine .... 
 
 Arsenic glass, (see Arsenic, Sulphides 
 
 of) 372 
 
 Arsenic, Iodide of . 
 
 Arsenic, Liver of (s. Sulphursenites) . 
 
 Arsenic, Ores of (pp. 360, 370). 
 
 Arsenic Oxides of. 
 
 Trioxide, Arsenious oxide or anhy- 
 dride 373 
 
 Arsenites 374 
 
 Pentoxide of Arsenic, Arsenic oxide 
 
 or anhydride .... 378 
 Arsenates 379 
 
 Arsenic, Oxybromide of ... 385 
 
 Arsenic, Oxychloride of ... 
 
 Arsenic, Oxj-iodide of . . . . 
 
 Arsenic, Oxysulphide of (see Sulphox- 
 arsenate of potassium, p. 395). 
 
 Arsenic, Sulphides of: 
 
 Disulphide or Hyposulpharsenious 
 
 acid 386 
 
 Hyposulpharsenites . . . 387 
 Trisulphide, Arsenious sulphide, or 
 
 Sulpharsenious acid ... 
 Sulpharsenites . . . 388 
 
THE FIRST VOLUME. 
 
 1123 
 
 Arsenic : PAGE 
 
 Pentasulphide, Arsenic sulphide, or 
 Sulpharsenic acid . . .391 
 Sulpharsenates ... 
 Arsenical cobalt, copper, iron, &c. (s. 
 
 the several metals). 
 
 Arsenical pyrites (s. Iron, Arsenides of: 
 
 Arsenical pyrophorus .... 396 
 
 Arsenic-rad'icles, Organic ... 
 
 Arsenides of Allyl . . . .397 
 
 Arsenides of Amyl .... 
 
 Arsenides of Ethyl .... 
 
 Arsenethyl . . . . . 
 
 Arsendiethyl or Ethyl-cacodyl . 
 
 Arsendiethylic acid . . .398 
 
 Arsentriethyl or Triethylarsine . 
 
 Arsenethylium or Tetrethylarso- 
 
 nium ..... 399 
 Arsen-bromethyl-triethylium . 400 
 Arsenvinyl-triethylium . . 
 Ethylene-hexethyl-diarsonium 
 Ethylene-triethyl-arsammonium. 
 Aurarsenethylium and Platarsen- 
 
 ethyliura .... 
 
 Arsenides of Methyl 
 
 Arsenmethyl, or Arsenmonomethyl 401 
 Dichloride, tetrachloride, chloro- 
 bromide, iodide, di-iodide, and 
 oxide of arsenmethyl. . 
 Arsenmethylic acid . . . 402 
 Sulphide of Arsenmethyl . 
 Arsendimethyl, or Cacodyl . . 408 
 Bromide of Cacodyl . . . 405 
 Chloride, oxychloride, chloro- 
 cuprite, and chloroplatinate 
 of cacodyl 
 
 Chloride of Cacoplatyl . . 
 Trichloride of Cacodyl . .406 
 Dibromochlride of Cacodyl . 
 Cyanide of Cacodyl ... 
 Fluoride and Iodide of Cacodyl 407 
 Oxide of Cacodyl . . . 
 
 Dioxide 
 
 Cacodylic acid .... 
 
 Cacodylates . . . .408 
 
 Selenide of cacodyl ... 
 Sulphide of cacodyl . . . 409 
 Bisulphide .... 
 
 Sulphocacodylic acid . . 
 Arsentrimethyl and Arsenmethy- 
 lium ...... 
 
 Arsendimethyl-diethylium . .410 
 
 Arsentrimethyl-ethylium . .411 
 
 Arsenmethyl-triethylium . . 
 
 Arsendimethyl-diamylium . . 
 
 Arsenide of Tetryl . . 412 
 
 Arsenide of Trityl 
 
 Arseniosiderite 
 
 Arsenite, or Arsenolite 
 
 Arsenomelane (s. Dufrenoysite) 
 
 Arsenosiderite 
 
 Arsenphyllite 
 
 Arsidogen 
 
 Arthanitin, or Cyclamin 
 Artichoke 
 Artocarpus incisa . 
 Arum esculentum . 
 Arum maculatum . 
 Arundo phragmites 
 Asa dulcis 
 Asafoetida 
 
 Asarin, or Asarone . . 414 
 
 Asarite ....... 
 
 Asaruin-oil ...... 
 
 Asbestos. Asbolan . . . .415 
 
 PAGE 
 
 Asboline 415 
 
 Asclepiadin 416 
 
 Asclepione 
 
 Ash of Organic Bodies : 
 
 Constituents .... 
 
 Preparation . . . .417 
 
 Analysis . .... 419 
 
 Ash, Volcanic . . . .420 
 
 Asparagine . . . . . 421 
 
 Asparagolite . .... 422 
 
 Asparagus officinalis .... 
 
 Asparamide (s. Asparagine) 
 
 Asparamic-acid (s. Aspartic Acid) . 
 
 Aspartic acid ...... 
 
 Active and inactive aspartic acid . 423 
 Compounds of aspartic acid with 
 
 other acids . . . . * . 
 
 Aspartates 424 
 
 Aspasiolite 425 
 
 Aspertannic acid 
 
 Asperula odorata 
 
 Asphalt 
 
 Ashphaltene, Petrolene, Asphalt-oil 426 
 Asphalt, artificial . . . .427 
 
 Asphodelus . . . . . 
 
 Aspirator ...... 
 
 Assacou, or Ussacou .... 428 
 
 Assamar 
 
 Aster tripolium 429 
 
 Astrucamite ...... 
 
 Astralite 
 
 Astrophyllite 
 
 Atacamite 
 
 Athamanta oreoselinum . . . 430 
 
 Athamantin 
 
 Athanor, or Acanor .... 
 
 Athar, or Attar 
 
 Atheriastite . 
 
 Atlas ore (s. Malachite) 
 
 Atlas spar (s. Satin spar) 
 
 Atmerythrin . . 431 
 
 Atmidoscopc . 
 
 Atmosphere . 
 
 Physical properties 
 
 Chemical composition . . 434 
 
 Estimation of Oxygen and Nitrogen 
 
 in the air 435 
 
 Estimation of Aqueous vapour . 437 
 
 Carbonic acid . . 
 
 Ammonia . . 439 
 
 Organic matter . 
 
 Atomic Volume 440 
 
 of Gases . . .441 
 
 Elementary bodies in 
 
 the liquid and solid state 442 
 
 Liquid compounds . 443 
 
 Solid compounds . 449 
 
 Atomic Weights 450 
 
 Determination of Atomic weights 
 
 by chemical considerations . 457 
 
 Atomic weight of Carbon . 459 
 
 Nitrogen . 460 
 
 Oxygen . 461 
 
 Chlorine . 463 
 
 Table of Atomic weights . 465 
 Determination of Atomic weights 
 
 by physical considerations . . 466 
 From the combining volumes 
 
 of gases and vapours . . . 
 From the specific heats of ele- 
 mentary atoms . . . 470 
 From isomorphous relations . 472 
 Atramentum stone . . . 473 
 Atriplex 
 
 c2 
 
1124 
 
 INDEX TO 
 
 PAGE 
 
 Atriplex verrucifera .... 474 
 
 Atropic acid ...... 
 
 Atropine 
 
 Augite, or Pyroxene .... 475 
 
 Augustite. Aurade .... 476 
 
 Aurantiin (s. Hesperidin) ... 
 Aurarsenethylium (s. Arsenides of 
 
 Methyl, p. 400). Aurichalcite . . 
 
 Aurotellurite. Automalite 
 
 Aurum mosaicum or musivum . . 
 
 Automolite (s. Gahnite) ... 
 
 Autunite. Avenin .... 
 
 Aventurin ...... 
 
 Aventurin glass . . . . 
 
 Aventurin glaze ..... 477 
 
 Avignon, grains of (s. Yellow Berries) . 
 
 Axe-stone 
 
 Axinite 
 
 Azadirine ...... 
 
 Azelaic acid 
 
 Azobenzene . . . . . . 
 
 Azobenzil 
 
 Azobenzoide 
 
 Azobenzoidine ..... 
 Azobenzoilide ..... 
 
 Azobenzoyl 
 
 Hydride of (s. Hydrobenzamide) . 
 
 Azocinnamyl, hydride of (s. Cinnamyl) 479 
 
 Azocodeine (s. Codeine) .... 
 
 Azodifune . . . . . 
 
 Azoerythrin (s. Orcein). ... 
 
 Azoleic acid (s. CEnanthylic Acid) . 
 
 Azolithofellic acid (s. Lithofellic Acid) . 
 
 Azolitmin (s. Litmus) .... 
 Azomaric acid (s. Pimaric Acid) 
 Azophenylamine . 
 
 Azorite 
 
 Azosulphide of Benzene (s. Benzoyl- 
 
 hydride, p. 568) . 
 Azote (s. Nitrogen) 
 
 Azotan 
 
 Azotides (s. Nitrides) . 
 Azoxybenzene 
 
 Nitrazoxy benzene . . 
 Isonitrazoxybenzene 
 
 Azoxj'difune 480 
 
 Azulmic acid 
 
 Azure blue (s. Smalt) .... 
 Azure-stone ) (s. Carbonates of Copper, 
 
 Azurite J p. 783). . 
 
 B. 
 
 Babingtonite . ... 480 
 
 Bablah, or Neb-neb . . . .481 
 
 Babul-gum, or Gond- babul . 
 Babylonian quartz .... 
 
 Bagrationite (s. Orthite) 
 
 Baierin or Baierite .... 
 
 Baikalite (s. Diopside) .... 
 
 Balance ....... 
 
 Chemical Balance . . . .482 
 
 Assay Balance . . . 483 
 
 Adjustment of Beam 
 
 Weights 484 
 
 Suggestions for care of, in Balance 486 
 
 Mechanical Theory of the Balance . 487 
 
 Elimination of Errors . . . 490 
 
 Ballu.s, or Balais Ruby . . .491 
 
 Ballesterosite 
 
 Balloon 
 
 Balsam 
 
 PA OB 
 
 Balsams, Oleo-resinous : 
 
 Canada balsam . . . .492 
 
 Copaiba, or Copaiva balsam . . 
 
 Mecca balsam, or Balm of Gilead . 495 
 Balsams containing cinnaniic acid : 
 
 Liquidambar 496 
 
 Peru balsam 
 
 Storax 497 
 
 Tolu balsam 498 
 
 Balsams, artificial 499 
 
 Baltimorite . 
 
 Bamlite . 
 
 Haralite or Bavalite . . . .500 
 
 Barbatimao . . . . . . 
 
 Bardiglione . . . . . 
 
 Baregin or Glairin .... 
 
 Barilla 
 
 Barium 
 
 Barium, Bromide of .... 501 
 
 Barium, Chloride of . . . 
 
 Barium, Cyanide of (s. Cyanides) . . 
 Barium, Detection and estimation of: 
 
 1. Reactions in the dry way . . 502 
 
 2. Reactions in the wet vray . . 
 
 3. Quantitative estimation . . 503 
 
 4. Atomic weight ... 
 
 5. Separation from other elements . 
 Barium, Fluoride of .... 504 
 
 Barium, Iodide of 
 
 Barium, Oxides of: 
 
 Protoxide: Baryta ... 
 
 Hydrate 505 
 
 Peroxide 
 
 Barium, Oxygen-salts of ... 506 
 Barium, Oxysulphides of ... 
 Barium, Phosphide of . . .507 
 
 Barium, Selenide of ....- 
 Barium, Sulphides of . . . 
 
 Protosulphide .... 
 
 Sulphydrate 508 
 
 Trisulphide 
 
 Pentasulpbide 
 
 Barley (s. Cereals) 
 
 Barnhardtite 
 
 Barocalcite. Barolite . 
 
 Barometer 
 
 Construction 609 
 
 Correction for capacity . . .512 
 Temperature . . 
 Capillarity . .513 
 Index error . 514 
 
 Directions for taking an observation 
 
 of the barometer . . . 515 
 
 Uses of the barometer . . . 516 
 
 Determination of altitudes . . 
 
 Meteorology .... 517 
 
 Aneroid barometer ... 
 
 Bourdon's Metallic barometer . 
 
 Macworth's Underground barometer 
 
 Barras ....... 
 
 Barsowite 
 
 Barvvood or Camwood ....__ 
 Baryta (s. Barium, Oxides of, p. 504). 
 Barytes (s. Heavy Spar) ... 
 Barytic fluorspar .... 
 
 Barytocalcite ..... 518 
 
 Baryto-coelestin ..... 
 Barvtophillite. Barvto-atrontianite . 
 Basalt . . ." . . . . 
 Basaltic hornblende .... 
 Basanite. Basanomelane ... 
 
 Base 519 
 
 Basicerine (s. Hydrocerite) ... 
 Basicity . . . . 
 
THE FIRST VOLUME. 
 
 1125 
 
 PAGE 
 
 Basilicum, oil of . . . . .519 
 
 Bassia latifolia 
 
 Bassic acid ......- 
 
 Bassorin ...... 
 
 Bastard Clover 
 
 Bastite 
 
 Basyl ....... 
 
 Batatas edulis 520 
 
 Bath 
 
 Bath-metal 
 
 Batrachite 
 
 Batracholeic acid 
 
 Baudisserite 
 
 Bauiite 
 
 Bavalite (s. Baralite, p. 500) 
 Bay-salt (s. Sodium, Chloride of) 
 
 Bdellium 523 
 
 Bean 
 
 Beaumontite 524 
 
 Bebiric acid ...... 525 
 
 Bebirine, or Bebeerine .... 
 
 Beckite 526 
 
 Beech 
 
 Beech-nut oil 527 
 
 Beer 
 
 Preparation .... 528 
 
 Analysis 
 
 Tables showing the Composition of 
 
 various kinds of Beer . 
 Original gravity of Beer- worts 
 Adulteration of Beer 
 Beguin's Volatile spirit 
 Belladonna, oil of. Belladonnine . 
 Bell-metal ore .... 
 
 Belmontin 
 
 Belonite (s. needle-ore). 
 
 Ben, oil of 
 
 Benic acid 
 
 Benzaldide (s. Benzoyl, Hydride of). 
 Benzamic acid (s. Oxybenzamic acid). 
 Benzamide . . 
 
 Benzomercuramide . . . 
 Benzacetosulphophenamide 
 Benzoeumylsulphophenamide . 
 Benzosalicyl amide . . . 
 Benzosulphophenamide . 
 Benzosulphophenargentamide 
 Benzosulphophenylsodamide . 
 Dibenzophenamide . 
 Benzamide, Substitution products of: 
 Bromobenzamide 
 Chlorobenzamide . 
 Nitrobenzamide 
 
 Dinitrobenzamide 
 Thiobenzamide . . 
 Benzamil , 
 
 Benzanilide (s. Phenylamine). 
 Benzene or Benzol .... 
 Substitution-products of Benzene : 
 Bromobenzene . 
 Dibromobenzene 
 Tribromobenzene 
 Chlorobenzene 
 Trichlorobenzene 
 Chlorodinitrobenzene 
 Nitrobenzene 
 
 Dinitrobenzene 
 Benzhydramide 
 
 Benzhydrocyanidc (s Benzamide) 
 Benzhydrol or Benzhydrolic acid 
 Benzidam (s. Phenylamine). 
 Benzidine .... 
 Diethylbenzidine 
 Tetrethylbenzidine . 
 
 530 
 
 533 
 534 
 536 
 537 
 538 
 
 539 
 
 540 
 
 541 
 
 542 
 543 
 
 541 
 
 545 
 
 Benzidine : PAGB 
 
 Iodide of Dimethyl-tetrethyl-benzi- 
 dammonium .... 545 
 
 Benzil 
 
 Benzilam 546 
 
 Benzilic acid 
 
 Benzilim . . . . . . 
 
 Benzimic acid 547 
 
 Benzimide 
 
 Benzin (s. Benzene). 
 Benzoacetic anhvdride (s. Acetic anhy- 
 dride, p. 21). " 
 
 Benzo-angelic anhydride (s. Angelic an- 
 hydride, p, 293). 
 
 Benzocarbolic acid (s. Benzoate of Phe- 
 nyl, p. 553). 
 
 Benzochlorhydrin 
 
 Benzocinnamic anhydride (s. Benzoic 
 
 anhydride, p. 557). 
 
 Benzocuminic anhydride (s. Benzoic an- 
 hydride, p. 293). 
 
 Benzoeumylsulphophenamide (s. Benza- 
 mide, p. 539). 
 
 Benzoen (s. Benzyl, Hydride of, p. 573). 
 Benzoeretic acid ..... 
 Benzo^lycollic acid .... 548 
 
 Benzohelicin 549 
 
 Benzoic acid : 
 
 History, sources, formation, pre- 
 paration ..... 
 Properties, decompositions . 550 
 
 Benzoates (metallic) . .551 
 
 Benzoic ethers . . . 552 
 
 Benzoate of Methyl 
 Ethyl 
 
 Ethylene . . 553 
 
 Amyl . 
 Allyl . 
 Benzyl . 
 Glycyl . 
 Phenyl 
 
 Bromophenyl . 554 
 
 Chlorophenyl 
 Dinitrophenyl 
 Trinitrophenyl 
 
 Benzoic acid, Substitution-products of: 
 Bromobenzoic acid 
 Chlorobenzoic acid . . . 555 
 
 Parachlorobenzoic acid 
 Nitrobenzoic acid 
 
 Nitrobenzoates (metallic) . 556 
 
 Nitrobenzoic ethers 
 
 Nitrobenzoate of Methyl 
 Ethyl 
 Dibromophenyl 
 Dinitrophenyl 
 
 Dinitrobenzoic acid . . 557 
 
 Nitrochlorobenzoic acid 
 Benzoic Alcohol (.s. Benzylic Alcohol, 
 p. 579). 
 
 Benzoic anhydride . . . . . 
 
 Beuzo-acetic, -cinnamic, -cuminic, 
 -myristic,-o3nanthylic,-pelargonic, 
 -stearic, and -valeric anhydrides . 558 
 Benzonitrobenzoic anhydride . . 
 Nitrobenzoic anhydride ... 
 
 Benzoicins 
 
 Benzoin 559 
 
 Acetyl-benzoin 
 Benzoyl -benzoin 
 Nitrobenzoyl-benzo n 
 Benzoinam 
 Benzoinamide 
 Benzoin-gum . 
 Benzolactic acid . . . .5(1 
 
1126 
 
 INDEX TO 
 
 PAGE 
 
 Benzolic Alcohol (s. Benzylene), 
 
 Benzoline (s. Amarine, p. 162). 
 
 Benzoline 662 
 
 Benzomercuramide (p. 539). 
 
 Benzomyristic anhydride (p. 558). 
 
 Benzone . 
 
 Dinitrobenzone .... 
 
 Benzonitrile 563 
 
 Chlorobenzonitrile .... 564 
 Nitrobenzonitrile .... 
 
 Benzonitrobeuzoic anhydride (p. 558). 
 
 Benzonitrocumide (s. Cumylamine). 
 
 Benzoenanthic anhydride (p. 558). 
 
 Benzopelargonic anhydride (p. 558). 
 
 Benzophenide (s. Benzoate of Phenyl, 
 p. 553). 
 
 Benzophenone (s. Benzone, p. 562). 
 
 Benzopiperide (s. Piperidine). 
 
 Benzopropylenyl (s. Benzoate of Ally 1, p. 552). 
 
 Benzosalicin (s. Populin). 
 
 Benzosalicylamic acid .... 
 
 Benzosalicylamide .... 565 
 
 Benzosalicylic acid .... 
 
 Benzosalicylimide (s. Benzamide, p. 539). 
 
 Benzostearic anhydride (p. 558). 
 
 Benzostilbin 
 
 Benzosuccinin . . . . . 
 
 Benzosulphophenamic acid (s. Benzamic 
 acid, p. 538). 
 
 Benzosulphophenaraide (s. Benzamide, p. 
 540). 
 
 Benzosulphophenamidyl, Chloride and 
 Amide (s. Benzamide, p. 540). 
 
 Benzosulphophenylsodamide (p. 540). 
 
 Benzosylanilide (s. Benzylene-phenyl- 
 amine, 577). 
 
 Benzotartaric acid . .... 
 
 Benzovaleric anhydride (p. 558) 
 
 Benzoyl . 
 
 Benzoyl, Bromide of . 566 
 
 Benzoyl, Chloride of . 
 
 Chloride of Chlorobenzoyl . 567 
 
 Chloride of Nitrobenzoyl . 568 
 
 Benzoyl, Cyanide of 
 
 Benzoyl, Hydride of: Benzaldine ; Bitter 
 
 Almond Oil 
 
 Benzoate of Hydride of Benzoyl . 569 
 Hydride with Chloride of Benzoyl . 
 Hydrocyanate of Hydride of Benzoyl 570 
 Hydride of Benzoyl with Chloride 
 
 of Calcium 
 
 Hydride of Benzoyl with acid Sul- 
 
 "phites of Alkali'metals . . 
 Substitution-products : 
 
 Hydride of Nitrobenzoyl . . 
 
 Thiobenzoyl . . 571 
 
 Thionitrobenzoyl . 572 
 
 Oxyiodide of Hydride of Benzoyl 
 
 Benzoyl, Iodide of 
 
 Benzoyl, Perchloride of (p. 566). 
 
 Benzoyl, Sulphide of . . . 
 
 Benzoyl, Sulphocyanide of (s. Sulphocy- 
 anobenzylene). 
 
 Benzoylazotide 
 
 Benzoyl-benzoin (s. Benzoin, p. 559). 
 
 Benzoyl-urea (s. Carbamide, p. 753). 
 
 Ber.zoylureid 573 
 
 Benzureid (s. Benzoyl-urea). 
 
 Benzyl : Toli/L, Toluenyl . 
 
 Benzyl, Chloride of .... 
 
 Benzyl, Cyanide of 
 
 Benzyl, Hydride of. .... 
 
 Hydride of Nitrobenzyl . . . 574 
 
 Dinitrobenzvl . . 575 
 
 PAGE 
 
 Benzyl, Iodide of . . . . . 575 
 Benzylamine: Toluidine ... 
 
 Cyanobenzylamine : Cyanotoluidine 576 
 
 Melobenzylamine : MdotoMdine 
 
 Benzethylamine 
 
 Benzyldiethylamine 
 
 Benzyltriethylium 
 
 Nitrobenzylamine 
 
 Tribenzylamine 
 
 Benzylene . . 577 
 
 Benzylene, Chloride of 
 Benzylene, Sulphide of 
 Benzylene-phenylamine 
 Benzylenic ethers . 
 
 Methyl-benzylenic ether 
 
 Ethyl- and Amyl-benzylenic ethers 578 
 
 Aceto-, Benzo-, Succino-, Sulpho- 
 
 and Valero-benzj'lenic ethers 
 Benzylethvlamine (p. 576). 
 
 Benzylic Alcohol 
 
 Benzylic Ether 579 
 
 Ethyl-benzylie ether ... 
 
 Beraunite 
 
 Berberine 
 
 Berengelite 580 
 
 Beresite 
 
 Bergamot, Oil of 
 
 Bergamot-camphor ; Bergaptene. 5&1 
 
 Berthierin 
 
 Berthierite or Haidingerite 
 
 Bertholletia excelsa 
 
 Beryl .... 
 
 Beryllium (s. Glucinum). 
 
 Berzelianite ... . 582 
 
 Berzeliite 
 
 Berzelin 
 
 Berzelite 
 
 Beta .... . 
 
 Betulin .... . 583 
 
 Betuloretic acid . . 
 
 Beudantin (s. Nephelin). 
 Beudantite ... . . 
 
 Bezetta 
 
 Bezoar 584 
 
 Bezoardic acid (s. Ellagic acid). 
 Bezoardicum animale .... 
 minerale .... 
 Bi- compounds (s. Di -compounds). 
 Bildstein (s. Agalmatolite> 
 Bile 
 
 Analysis 585 
 
 Pettenkofer's test . . . .586 
 
 Composition of Bile of varions 
 animals ..... 
 
 Putrefaction of Bile . . . 587 
 
 Biliary Calculi . . . .588 
 Bimstein (s. Pumice-stone). 
 Binary Theory of Salts . 
 
 Binnite . 
 
 Biotin (s. Anorthite, p. 308). 
 
 Biotite (s. Mica). 
 
 Birch 
 
 Birch fungus, juice, oil, resin, and tar 589 
 
 Birdlime 
 
 Bismuth 590 
 
 Bismuth, Acicular . . . .591 
 
 Bismuth, Alloys of 
 
 Bismuth, Bromide of . . . 
 
 Bismuth, Chlorides of: 
 
 Trichloride 
 
 Dichloride . . . 
 
 Bismuth Cupreous 592 
 
 Bismuth, Detection and Estimation of: 
 
 Blowpipe reactions .... 
 
THE FIRST VOLUME. 
 
 1127 
 
 Bismuth, Detection and estimation of: 
 
 Liquid reactions 
 
 Quantitative estimation . 
 
 Atomic weight 
 
 Separation from other elements 
 
 Valuation of Bismuth ores 
 Bismuth, Fluoride of ... 
 Bismuth, Iodide of. . . 
 Bismuth, Oxides of ... 
 
 Trioxide, or Bismuthous oxide 
 
 Pentoxide, or Bismuthic oxide 
 
 Bismuthates 
 
 Bismuth, Oxychloride of (p. 591). 
 Bismuth, Oxygen-salts of 
 Bismuth, Phosphide of 
 Bismuth, .Selenide of ... 
 Bismuth, Sulphides of . 
 Bismuth, Sulphochloride of . 
 Bismuth, Telluric (s. Tellurium). 
 Bismuth, Telluride of ... 
 Bismuth-glance, or Bismuthine . 
 Bismuth-nickel 
 
 Bismuth-ochre .... 
 Bismuth-radicles, Organic 
 
 Bisethyl 
 
 Bistriethyl, or Triethyl-bismuthine 
 
 Bismuth-silver 
 
 Bismutite 
 
 Bissa-bol 
 
 Bistre 
 
 Bitter-almond oil 
 
 Bitter-almond water .... 
 
 Bitter principle 
 
 Bittern 
 
 Bitterspar, or Rhombspar 
 
 Bittersweet 
 
 Bitumen 
 
 Biuret 
 
 Bixin 
 
 Black Band 
 
 Black Chalk 
 
 Blackjack 
 
 Black Lead (s. Carbon, p. 758). 
 
 Black Wadd 
 
 Blanchinine 
 
 Blanquette 
 
 Blaps obtusa ...... 
 
 Bleaching 
 
 Bleaching Powder (a. Hypochlorites). 
 
 Bleinierite 
 
 Blende 
 
 Blodito 
 
 Blood 
 
 Its analysis 
 
 Blood -stone (s. Jasper) . 
 Blowpipe 
 
 Blowpipe analysis . 
 
 Table of behaviour of Metallic 
 Oxides, with Microcosmic salt 
 and Borax 
 
 Table Blowpipe .... 
 
 Oxyhydrogen Blowpipe 
 Blue, Prussian (s. Cyanides of Iron). 
 
 Blue, Saxon 
 
 Bodenite 
 
 Bog-butter 
 
 Bog-head Coal (s. Coal). 
 Bog -ores (s. Iron). 
 
 Bobeic acid 
 
 Boiling Point (s. Heat). 
 
 Bole 
 
 Bolognian Stone 
 
 Boleticacid 
 
 Boletus ....... 
 
 PAGE 
 592 
 
 593 
 594 
 
 595 
 
 596 
 
 597 
 
 599 
 
 600 
 
 601 
 
 602 
 
 610 
 612 
 
 613 
 
 614 
 616 
 
 617 
 
 618 
 
 PAGE 
 
 Boloretin ...... 619 
 
 Boltonite. Bolus ... _ 
 
 Bone 
 
 Diseased bones .... 623 
 
 Fossil bones 
 
 Bone-black 624 
 
 Bone-oil. Bonsdorffite .... 625 
 Boracic acid (s. Boric acid, p. 636). 
 
 Boracite _ 
 
 Borax (s. Borate of Sodium, p. 645). 
 Borides (s. Boron, p. 629). 
 Borneene. Borneol . . . .626 
 
 Bornite. Borocalcite . 
 Boron . . ... . .627 
 
 Boron, Bromide of 629 
 
 Boron, Chloride of 
 
 Ammonio-chloride .... 
 Boron, Chlorocyanide of (s. Cyanogen, 
 
 Chloride of). 
 Boron, Detection and Estimation of: 
 
 Reactions . . . . .630 
 
 Quantitative estimation . . 
 
 Separation from other elements . 631 
 Atomic weight . . . .632 
 
 Boron, Fluoride of . . . . 
 Fluoboric acid . . . .638 
 
 Hydrofluoboric acid 
 
 Boron uorides 
 
 Boron, Iodide of 63,5 
 
 Boron, Nitride of 
 
 Boron, Oxide of: Boric anhydride . 
 
 Boric acid 636 
 
 Borates 639 
 
 Borates of Aluminium . 641 
 Ammonium 
 
 Barium . . 642 
 Cadmium 
 Calcium 
 
 Cobalt . . 643 
 Copper . 
 Iron 
 
 Lead . 
 
 Borochloride of Lead . 644 
 Boronitrate of Lead 
 Borate of Lithium . 
 Borates of Magnesium 
 Borate of Nickel . 
 Borates of Potassium 
 
 Silver . . 645 
 Sodium . 
 
 Strontium . 649 
 Zinc . 
 
 Boric Ethers: Borates of Amyl . 
 
 Ethyl 650 
 
 Methyl 
 
 Boron, Sulphide of . . . .651 
 
 Boronatrocalcite ..... 
 
 Botryogen 
 
 Botryolite 
 
 Boulangerite. Bournonite . 
 
 Bovey Coal 
 
 Bowenite (s. Serpentine). 
 Boyle's fuming Liquor (s. Sulphides of 
 Ammonium, p. 194). 
 
 Bragite 
 
 Brain (s. Nervous Tissue). 
 
 Bran 652 
 
 Branchite ...... 
 
 Brandisite (s. Clintonite). 
 
 Brandy 
 
 Brass 653 
 
 Brassica 
 
 1. Brassica oleracea : Cabbage . . 
 
 Composition of Cabbage-leaves 
 
1128 
 
 INDEX TO 
 
 Braseica : 
 
 Ash of different varieties of 
 Cabbage 
 
 2. Brassica Napus : Rape 
 
 Ash of Seed and Straw . 
 
 3. Brassica Rapa : Turnip . 
 
 Composition of Ash . . 
 Brassic acid 
 
 654 
 
 655 
 
 ! 
 
 *** 
 
 Bray era anthelmintica 
 Brazil wood . 
 Bread ... 
 
 Fermented . 
 
 Unfermented . 
 Aerated bread 
 Brean (s. Icica-resin). 
 
 Brein and Breidin (s. Arbol-a-brea, p. 346) 662 
 Breislakite. Breithauptite . 
 
 Bremer Green ..... 663 
 
 Breunerite (s. Magnesite). 
 
 Brevicite (s. Natrolite). 
 
 Brewsterite ...... 
 
 Brewstolin ...... 
 
 Bricks . . ...... 
 
 floating ..... 6G4 
 
 Brilliant ...... 
 
 Brimstone (s. Sulphur). 
 
 Brindonia indica . . ... . 
 
 Britannia metal ..... 
 
 Brithyne (s. Glauberite). 
 
 British gum (s. Dextrin). 
 
 Brittle Silver-ore. Brocatello . . 
 
 Broccoli (s. Brassica). 
 
 Brochantite ...... 
 
 Broddbo Tantalite (s. Tantalite). 
 Brogniardite ...... 
 
 Brogniartin, or Brogniartite *(s. Glau- 
 
 berite). 
 Bromacetic acid ..... 
 
 Bromacetates . . . . . 665 
 
 Dibromacetic acid .... 666 
 
 Bromacetins (s. Acetins, p. 26). 
 
 Bromal ....... 
 
 Bromaloi'n (s. Alo'in, p. 148). 
 llromamide (s. Nitrogen, Bromide of)* 
 Bromanil (s. Quinone). 
 Bromanilamic acid (s. Quinonic acid). 
 Bromaniloide (s. Tribromopheny la- 
 
 mine, under Phenylamine). 
 Bromanisic acid (p. 301). 
 Bromanisol (p. 305). 
 Bromargyrite.^Bromein 
 JJrometheride (s. Vinyl, Bromide of). 
 aBiomethionessil .... 
 
 Broinhydric acid (p. 672). 
 Bromhydrins ..... 
 
 Mono-, Di-, and Tribrornhydrin 
 
 Epibromhydrin 
 
 Hexaglyceric Bromhydrin 
 
 Hemibromhydrin . 
 Bromic acid . ..... 
 
 Bromic Silver ..... 
 
 Bromides ...... 
 
 Bromide of Hydrogen: Bromhydric 
 
 or Hydrobromic acid . 
 Bromides, Metallic .... 
 
 Bromides of Organic radicles 
 Bromindamite ..... 
 
 Bromindoptene ..... 
 
 Bromine . ..... 
 
 Bromine, Chloride of .... 
 
 Bromine, Detection and Estimation of: 
 
 1. Reactions ..... 6 
 
 2. Quantitative estimation 
 
 667 
 
 CG8 
 669 
 
 672 
 672 
 
 674 
 675 
 
 67(5 
 
 PAG* 
 
 Bromine, Detection and estimation of: 
 Estimation in presence of Chlo- 
 rine and Iodine 678 
 
 3. Atomic weight . 679 
 
 Bromine, Fluoride of . 
 
 Bromine, Oxygen-acids of 
 
 Bromine, Selenide of . 680 
 
 Bromine, Sulphide of . 
 
 Bromiodoform , 
 
 Bromisatic acid (s. Isatic acid). 
 Bromi satin (s. Isatin). 
 
 Bromite 
 
 Bromi tonic acid (s. Citraconic acid, De- 
 compositions of, p. 993). 
 Bromlite (s. Alstonite, p. 149). 
 Bromoform. Bromopicrin . 
 
 Bromosamide (s. Salicylamide). 
 Bromotriconic acid 1 , n-. ., nocx 
 Bromoxaform j <>* Cltne *> P- 996 >' 
 Jiromus. liromyrite .... 
 
 Bronze 
 
 Bronzite 
 
 Brookite 681 
 
 Brossite ...... 
 
 Broussonnettia tinctoria ... 
 
 Brown berries 
 
 Brucine 
 
 Salts of Brucine . . . .682 
 
 Bromo-brucine . . . .683 
 
 Ethyl-brueine . 
 
 Brucite 684 
 
 Brunolic acid . 
 
 Brunswick green . 
 
 Bryo'idin . . . " . . . 
 Bryouin . . ... . 
 
 Bryoretin 685 
 
 Bubulin ....... 
 
 Bucholzite 
 
 Bucklandite (s. Epidote). 
 Buckthorn (s. Bhamnus). 
 Buckwheat ...... 
 
 Colouring matters of Buckwheat . 686 
 Bucurumanga resin 
 Buenin. Buhrstone 
 Bukku leaves 
 Buratite 
 
 Burette (p. 256). 
 Burgundy Pitch or Resin 
 Bursera gummifera 
 Bustamite (s. Rhodonite). 
 Butea gum 
 Butic acid . . . . . .687 
 
 Butter . . . . 
 
 Butter of Antimony, Tin, &c. 
 Butyl (s. Tetryl). 
 
 Butylactic acid 688 
 
 Butvracetic acid 
 
 Butyral 689 
 
 Chlorobutyrals . < 
 Butyraldehyde 
 
 Butyraldehyde-ammonia 690 
 
 Butyramide . 
 
 Mercuric butyramide 
 Butyric acid .... 691 
 
 Butyrates ... 692 
 
 Butyric acid, Substitution-derivat ves of 693 
 
 Dibromobutyric acid . 
 
 Dichlorobutyric acid . 694 
 
 Tetrachlorobutyric acid 
 
 Thiobutyric acid . 
 Butyric anhydride 
 Butyric ethers . . . 695 
 
 Butyrateof Allyl . 
 Amyl 
 
THE FIRST VOLUME. 
 
 1129 
 
 Butyric ethers : 
 
 Butyrate of Ethyl . 
 Ethylene 
 
 Glyceryl 
 Methyl 
 
 696 
 
 697 
 
 Methy 
 Butyridin 
 Butyrins : 
 
 Mono- and Dibutyrin 
 
 Tributyrin . . 
 
 Natural butyrin . . 
 
 Butyrite ... 
 Butyrochlorhydrin *- 
 
 Butyroleic acid . , 
 Butyrolimnodic acid (s. Bog-butter, p. 617). 
 
 Butyrolactic acid 
 
 Butyrone 
 
 Butyronitric acid .... 698 
 
 Butyronitrile ...... 
 
 Butyrum antimonii . . . . 
 
 Butyrureid (s. Butyryl urea) 
 
 Butyryl 
 
 Bromide, Chloride .... 
 
 Iodide 699 
 
 Butyryl-urea (s. Carbamide, p. 753). 
 Buxine ...... 
 
 Byssolite ...... 
 
 ByssnsMytili 
 
 Bytownite ...... 
 
 C. 
 
 Cabbage 700 
 
 Cabbagiine 
 
 Cabocle ....... 
 
 Cacao ....... 
 
 Cacao-fat 701 
 
 Cacao-red 
 
 Cachalagua. Cacholong ... 
 Cachoutannic acid (s. Catechu, p. 817). 
 
 Cacotheline . 
 
 Cacoxene . . ... 702 
 
 Cactus ... ... 
 
 Cadet's Fuming Liquor (p. 403). 
 
 Cadie gum . ... 
 
 Cadmium . . ... 
 
 Cadmium, Alloys of ... 703 
 
 Cadmium, Bromide of . 
 
 Cadmium, Chloride of . . . 
 
 Double salts of Chloride of Cadmium 
 
 Cadmium : Detection and Estimation of 704 
 
 1. Blowpipe reactions ... 
 
 2. Liquid reactions ... 
 
 3. Quantitative estimation . . 705 
 
 4. Separation from other elements . 
 
 5. Atomic weight 
 Cadmium, Fluoride of 
 Cadmium, Iodide of 
 Cadmium, Nitride of 
 
 Cadmium, Oxides of ... 706 
 
 Cadmium, Phosphide of ... 
 
 Cadmium, Sulphide of . . . . 
 
 Cadmium-ethyl 
 
 Caesium 707 
 
 Caffeic acid (s. Caffetannic acid, p. 709). 
 
 Caffeine or Theine ..... 
 Salts of Caffeine . . " . .709 
 
 Caffeone 
 
 Caffetannic acid 
 
 Ca'incic acid . . . . . ,710 
 Cairnga m stone (s. Quartz). 
 
 Cajeput, oil of 
 
 Cajputene 711 
 
 Isocajputene 
 
 Paracaj ptitene .... 
 
 Bromide of Cajputeue ... 
 
 Cajputene: 
 
 Chloride of Cajputene . 
 
 Hydrates of Cajputene . 
 
 Hydrochlorates of Cajputene . 
 
 Hydriodate of Cajputene 
 Calaite (s. Turquois). 
 Calamine ..... 
 Calamine, Siliceous 
 
 Calamite 
 
 Calcareous spar (s. Calcspar). 
 Calcedony (s. Chalcedony). 
 Calchantum ..... 
 Calcination. Calcite 
 
 Calcium 
 
 Calcium, Bromide of ... 
 Calcium, Chloride of ... 
 Calcium, Detection and Estimation of 
 
 1. Reactions in the dry way . 
 
 2. Reactions in the wet way . 
 
 3. Quantitative estimation 
 
 4. Separation from other elements 
 
 5. Atomic weight . 
 Calcium, Fluoride of ... 
 Calcium, Oxide of . 
 
 Calcium, Oxychloride of (p. 716). 
 Calcium, Oxygen-salts of 
 Calcium, Oxysulphide of 
 Calcium, Phosphide of . 
 Calcium, Selenides of ... 
 Calcium, Sulphides of ... 
 
 Calc-sinter 
 
 Calcoferrite 
 
 Calcspar 
 
 Calctuff . 
 
 Calculus 
 
 Calderite 
 
 Caledonite 
 
 alendulin 
 
 Calico-printing .... 
 
 Californin 
 
 Calisaya bark. -Callais . 
 
 Calluna vulgaris .... 
 
 Callutannic acid .... 
 
 Calluxanthin 
 
 Calomel (s. Mercury). 
 Calophyllum resin "... 
 Calorimeter . ... 
 
 Calorimotor 
 
 Calstronbaryte .... 
 
 Ualyptolite 
 
 Damboley resin .... 
 Camellia japonica .... 
 3ampeachy wood (s. Logwood). 
 ri amphamic acid, and Camphamide 
 
 (p. 729). 
 
 Jamphene 
 
 3amphenes ..... 
 Damphereues ..... 
 3ampheryl or Campherile 
 
 Uamphic acid 
 
 Damphides . . . . 
 3amphilene . . . 
 Damphimide (p. 732). 
 Damphin ..... 
 
 Camphine 
 
 amphocreosote . 
 
 Damphol 
 
 Dampholene . . 
 Uampholic acid . 
 
 Damphone 
 
 2amphomethylic acid (p. 733). 
 Camphor 
 
 t'AOK 
 
 . 711 
 . 712 
 . 713 
 
 714 
 
 715 
 
 71G 
 
 717 
 718 
 719 
 
 720 
 
 721 
 
 722 
 
 723 
 
 Dextro- camphor 
 Lajvo-camphor 
 
 725 
 
 726 
 
 727 
 
 729 
 
1130 
 
 INDEX TO 
 
 Camphor : 
 
 Inactive camphor 
 
 Camphor, artificial (s. Turpentine). 
 Camphor of Borneo (s. Borneol, p. 626). 
 
 Camphor, oil of 
 
 Camphoramic acid . 
 Camphoranilic acid (s. Phenyl-campho- 
 
 ramic acid). 
 
 Camphoresin . . . . 
 
 Camphoric acid : 
 
 Dextro-camphoric acid . 
 
 Laevo-camphoric acid 
 
 Inactive camphoric acid 
 
 Camphorates 
 
 Camphoric anhydride .... 
 Camphoric ethers : 
 
 Camphorate of Ethyl 
 
 Camphorate of Ethyl and Hydrogen 
 
 Camphorate of Methyl and Hy- 
 drogen 
 
 Camphorimide 
 
 Camphorin ...... 
 
 Camphorone 
 
 Camphoryl 
 
 Camphosulphuric acid (s. Sulphocam- 
 
 phoric acid). 
 Camphovinic acid (s. Campnoric ethers, 
 
 p. 732). 
 Camphrene ...... 
 
 Camphrone . . . . . 
 
 Camwood (s. Barwood, p. 517). 
 
 Canaanite 
 
 Canada balsam (s. Balsams, p. 492). 
 
 Cancerin 
 
 Cancha-lagua (s. Cachalagua, p. 701). 
 Cancrinite. Candite .... 
 
 Canella alba 
 
 Cannabis indica ..... 
 
 Cannabis sativa 
 
 Cannamine (s. Brucine, p. 681). 
 
 Cannel coal (s. Coal). 
 
 Cannon metal (s. Copper, Alloys of). 
 
 Can tharides 
 
 Cantharidin 
 
 Cantonite . ... 
 Canton's phosphorus 
 Caoutchene . 
 Caoutehin 
 
 Hydrochlorate of caoutch n 
 Caoutchouc 
 
 Vulcanised caoutchouc 
 
 Hardened caoutchouc ; Ebonite 
 Caoutchoucin (p. 739). 
 Capers (s. Capparis). 
 Caphopicrite (s. Rhein). 
 Capillarity ..... 
 
 Capnomor 
 
 Caporcianite ..... 
 Capparis spinosa .... 
 
 Capral 
 
 Capramide 
 
 Capric acid 
 
 Capric aldehyde .... 
 Caprinamide (s. Capramide). 
 Caprocianite (s. Caporcianite). 
 
 Caproene 
 
 Caproic acid 
 
 Caproic alcohol (s. Hexylic Alcohol). 
 Caproic aldehyde .... 
 Caproic anhydride. 
 Caproic ethers .... 
 
 Caprone 
 
 Capronitrile 
 
 Capronoyl 
 
 PAG 
 
 72 
 
 730 
 
 731 
 
 73 
 733 
 
 734 
 
 735 
 
 736 
 
 737 
 738 
 739 
 740 
 
 741 
 742 
 
 743 
 
 744 
 
 Caproyl . . . . . . . 744 
 
 Caproylamine (s. Hexylamine). 
 Caproylene (s. Hexylene). 
 
 Capryl, or Rutyl 745 
 
 Caprylamine (s. Octylamine). 
 Caprylene (s. Qctylene). 
 
 Caprylic acid 
 
 Nitrocaprylic acid .... 
 Caprylic alcohol (s. Octylic Alcohol). 
 
 Caprylic aldehyde 
 
 Caprylic anhydride .... 746 
 
 Caprylic ethers , 
 
 Caprylone 747 
 
 Caprylyl 
 
 Capsicine, ...... 
 
 Caput mortuum . . . . . 
 
 Caragheen moss 
 
 Carajuru, Crajuru, or Carcuru . . 
 
 Caramel 
 
 Caramelane, Caramelene, Caramelin 748 
 
 Caranna 749 
 
 Carapa bark 
 
 Carapa oil 
 
 Carat . . . . . . . 
 
 Carbamic acid. 
 
 Carbamates of Ammonium, Amyl, 
 
 and Ethyl . . . . . 
 
 Carbamates of Methyl and Tetryl . 
 
 Ethyl-carbamic acid 
 
 Ethyl-carbamate of Ethyl, or 
 
 Ethyl-urethane 
 Phenyl- carbamic acid . 
 Phenyl-carbamates of Ethyl and 
 Methyl .... 
 
 Carbamide 
 
 Substitution-products of Carbamide : 
 
 Compound Ureas : 
 a. Carbamides or Ureas containing 
 
 Acid Radicles : 
 Acetyl-carbamide 
 Benzoyl-carbamide 
 B uty ry 1 -carbarn ide 
 Valeryl-carbamide 
 /3. Carbamides or Ureas containin 
 
 Basylous Radicles : 
 Allyl-carbamide 
 
 Allyl-sulphocarbamide 
 
 Diallyl-carbamide . 
 Amyl -carbamide . . 
 Benzyl-carbamide 
 Eth} r l- carbamide 
 
 Diethyl-carbamide . 
 
 Ethyl-allyl-carbamide . 
 
 Ethyl -allyl -sul phocarbamide 
 
 Ethyl-amyl-carbamide . 
 Methyl-carbamide 
 
 Dimethyl-carbamide 
 
 M ethyl-ethyl -carbamide 
 Naphthyl-carbamide . 
 
 Naphthyl-allyl-carbamide 
 Phenyl-carbamide 
 
 Ethyl-phenyl-carbamide 
 
 Nit ropheny I- carbamide . 
 
 Diphenyl-carbamide 
 Phenyl-sulphocarbamide . 
 
 Phenyl-allyl-sulphocarbamide 
 
 Diphenyl -sul phocarbamide 
 Piperyl-carbamide 
 
 M e t hy 1 - pipery 1 - carbamide 
 larbanil (s. Cyanic Ethers). 
 arbanilide(s."Diphenyl-carbamide,p.756). 
 /arbanilic acid (s. Phenvl-carbamic acid, 
 p. 751). 
 
 750 
 751 
 
 52 
 
 753 
 
 rsi 
 
 755 
 
 "56 
 
 757 
 
THE FIRST VOLUME. 
 
 1131 
 
 Carbanilethane and Carbanimethylane 
 (p. 752). 
 
 Carbazote 757 
 
 Carbazotic acid (s. Picric acid). 
 
 Carbides, or Carburets . . . . 
 
 Carbobenzide (s. Benzone). 
 
 Carbobenzoic acid (s. Cinnamein). 
 
 Carbo -hydrogens (s. Hydrocarbons). 
 
 Carbolic acid (s. Phenic acid). 
 
 Carbon . 
 
 1. Diamond 
 
 2. Graphite 758 
 
 3. Anthracite 759 
 
 4. Carbon obtained from organic 
 
 substances by dry distillation 
 or imperfect combustion : 
 
 a. Wood-charcoal . . 
 
 b. Coke .... 760 
 
 c. Metallic carbon, Glance-coal 
 
 d. Lamp-black ... 
 
 e. Animal charcoal . . 761 
 Absorbent power of charcoal . 
 Platinised charcoal . . 762 
 Charcoal as a precipitant and deo 
 
 doriser .... 
 
 Compounds of carbon . . 763 
 
 Carbon, Bromides of ... 764 
 
 Carbon, Chlorides of ... 
 
 Tetrachloride 765 
 
 Trichloride 766 
 
 Bichloride 767 
 
 Protochloride 768 
 
 Carbon, Chlorobromide of . , 
 
 Carbon, Detection and Estimation of . 
 
 Atomic weight of Carbon . . 769 
 
 Carbon, Iodide of 770 
 
 Carbon, Nitride of 
 
 Carbon, Oxides of 
 
 Dioxide or Carbonic annydride . 771 
 
 Liquid Carbonic anhydride . 
 
 Solid Carbonic anhydride . . 772 
 
 Carbonic acid .... 
 
 Protoxide or Carbonic oxide . . 773 
 
 Carbon, Oxychloride of: Phosgene . 774 
 
 Carbon, Sulphides of: 
 
 Disulphide 775 
 
 Protosulphide 77 
 
 Carbon, Sulphochloride of . . - 
 
 Carbonates .... . 778 
 
 Carbonate of Aluminium . . 77 
 Carbonates of Ammonium 
 Carbonates of Barium, Bismuth, 
 
 Cadmium, Calcium . . . 780 
 Carbonates of Cerium, Chromium, 
 
 Cobalt .... .782 
 
 Carbonates of Copper . . . 783 
 Carbonates of Didymium and Glu- 
 
 cinum 784 
 
 Carbonates of Iron: 
 
 Ferric Carbonate .... 
 Ferrous Carbonates . . . 785 
 Carbonate of Lanthanum . . 
 Carbonates of Lead . . . . 78( 
 Carbonate of Lithium . . . 787 
 Carbonates of Magnesium 
 Carbonates of Manganese, Mercury, 
 
 Nickel 78S 
 
 Carbonate of Palladium . . .790 
 Carbonates of Potassium : 
 
 Dipotassic or Neutral carbonate . 
 Mono-potassic or Di acid carbo- 
 nate 791 
 
 Sesquicarbonate .... 792 
 Carbon-ate of Silver 
 
 PAGK 
 
 Carbonates : 
 
 Carbonates of Sodium : 
 Disodic or Neutral carbonate . 792 
 Monosodic or Di-acid carbonate . 795 
 Tetrasodic or Sesquicarbonate . 796 
 
 Carbonate of Sodium and Potassium 
 
 Carbonate of Sodium and Calcium . 797 
 
 Carbonates of Strontium, Thorium, 
 Uranium . . . . . 
 
 Carbonate of Yttrium . . 798 
 
 Carbonates of Zinc . 
 
 Carbonate of Zirconium 
 Carbonic acid and anhydride (p. 7 0). 
 Carbonic ethers ... . 
 
 Carbonate of Allyl . . 800 
 
 Carbonate of Amyl 
 
 Carbonate of Ethyl 
 
 Tetrachlorocarbonic ether 
 
 Perchlorocarbonic ether 
 
 Carbonate of Eth3'l and Potassium 801 
 
 Carbonate of Methyl and Barium . 
 
 Carbonate of Methyl and Ethyl . 
 
 Carbonate of Phenyl and Hydrogen 
 
 Carbonate of Tetryl (or Butyl) . 
 Carbonitrotoluylic acid . 
 
 Carbonyl . . 802 
 
 Carbopyrolic acid 
 Carbostyril . 
 Carbothiacetonine 
 Carbothialdine 
 Carbotriamine 
 
 Carbomethyltriamine 
 
 Carbotriethyltriamine 
 
 Carbophenyltriamine 
 
 Carbotriphenyltriamine 
 Carbovinic acid (s. Carbonic ethers, p. 801). 
 Carbovinomethylide (syn. with Carbo- 
 nate of Ethyl and Methyl, p. 801). 
 
 Carbuncle 803 
 
 Carbureic acid (syn. with Allophanic 
 
 acid, p. 132). - 
 
 Garbyl, Sulphate of (syn. with Ethionic 
 anhydride). 
 
 Cardamine amara 
 
 Cardamom oil 
 
 Cardol 
 
 Carex 
 
 Carica papaya 804 
 
 Caries (s. Bone, p. 623). 
 
 Carinthin 
 
 Carmidine 
 
 Carminaphtha 
 
 Carmindin ... 
 
 Carmine, Carminic acid 
 
 Carminite, Carmine spar 805 
 
 Carmufellic acid . . 
 
 Carnallite. Carnat . 
 
 Carnauba wax 
 
 Carnelian 
 
 Caroluthin 
 
 Carotin 
 
 Carpholite . . . . . .806 
 
 Carphosiderite 807 
 
 Carphostilbite 
 
 Carpobalsamum 
 
 Carrolite 
 
 Carragheen moss (s. Caragheen moss, 
 p. 747). 
 
 Carrot 
 
 Carrot, oil of 
 
 Carthamin 808 
 
 Cartilage 
 
 Carvene, Carvol, and Carvacrol . . 
 Caryophyllic acid (s. Eugenic acid). 
 
1132 
 
 INDEX TO 
 
 818 
 
 PAGE 
 
 Caryophyllin . . . . .809 
 
 Cascalho . . 
 
 Cascarilla bark .... 
 
 Cascarilla, oil of 
 Casearillin . 
 Case-hardening 
 
 Casein 810 
 
 Casein, vegetable (s. Legumin). 
 
 Cassava 813 
 
 Cassell yellow (s. Lead, Oxychloride of). 
 
 Cassia caryophyllata 
 
 Cassia cinnamonea 
 
 Cassia fistula . 
 
 Cassia buds . 
 
 Cassiin . . 814 
 
 Cassiterite /. 
 
 Cassiterotantalite 
 
 Cassius, Purple of 
 
 Castelnaudite . 
 
 Castilloya elastica 
 
 Castine 
 
 Castor .;..... 
 
 Castoreuto 
 
 Castorin; 815 
 
 Castor oil 
 
 Catalysis 
 
 Catapleiite 
 
 Catawbarite 816 
 
 Catechu 
 
 Catechine ; Catechucic acid 
 
 Catechu-tamiic acid 817 
 
 Catha edulis . 
 Cathartin 
 
 Cathode, or Kathode 
 Catlinite . 
 Cat's eye 
 
 Caulophyllin 
 
 Causticity 
 
 Cavolinite (s Elaeolite and Nephelin). 
 
 Cawk 
 
 Cedar, Oil of 
 
 Cedrene 
 
 Cedrin (s. Cedron). 
 
 Cedriret 
 
 Cedron 
 
 Celestin (s. Coelestin). 
 Cellulic acid (a. Pectic acid). 
 Cellulose 
 
 Solution of Cellulose 
 
 Celtis . 
 
 Cement 
 
 Cementation 822 
 
 Cement Copper 
 
 Centaurin (s. Cnicin), 
 Cephalis (s. Ipecacuanha). 
 
 Ceradia fuscata 
 
 Ceraicacid 
 
 Cerain 
 
 Cerancephalote (s. Cephalote). 
 
 Cerantic acid 
 
 Cerasin 823 
 
 Cerasus 
 
 Cerate ....... 
 
 Ceraunite (s. Nephrite). 
 
 Cerealin 
 
 Cereals ....... 
 
 Cerebric acid 829 
 
 Cerebrin 
 
 Cerebrol . 830 
 
 Cerebro-spinal fluid .... 
 
 Cerebrate ...... 
 
 Ceric acid ...... 
 
 Cerin ...... . 
 
 Cerine (s. Orthite). 
 
 820 
 
 PAGE 
 
 Cerinin . . . . . . . 831 
 
 Cerite 
 
 Cerium . . .... . 
 
 Cerium, Bromide of .... 832 
 
 Cerium, Chlorides of . . . 
 
 Cerium, Detection and Estimation of . 
 
 1. Reactions ... . 833 
 
 2. Quantitative estimation . . 
 
 3. Separation from other elements . 
 
 4. Atomic weight .... 
 Cerium, Fluorides of .... 834 
 Cerium, Oxides of ... . 
 
 Cerous oxide ..... 
 
 Ceroso-ceric oxide .... 
 
 Ceric oxide ..... 835 
 
 Cerium, Oxygen-salts of 
 
 Cerium, Phosphide of . . . . 
 
 Cerium, Selenide of .... 
 
 Cerium, Sulphides of . . . 
 
 Cerolein 836 
 
 Cerolite, or Kerolite . 
 
 Ceropic acid 
 
 Cerosic acid 
 
 Cerosin 
 
 Cerotene 
 
 Ceroticacid 
 
 Chlorocerotic acid .... 83'. 
 Cerotic ethers : 
 
 Cerotate of ethyl . . . . - 
 
 Cerotate of ceryl ; Chinese wax . 
 Cerotin (p. 838). 
 
 Cerotinone -. 
 
 Ceroxylin: Palm-wax . 
 
 Cerumen of the ear - 
 
 Ceruse (s. Carbonates of lead, p. 786). 
 
 Cerusite (p. 786). 
 
 Cervantite ...... 
 
 Ceryl, Hydrate of: Cerylic alcohol, Cero- 
 tin 838 
 
 Cetene, or Cetylene .... 
 
 Cetic acid 
 
 Cetin 
 
 Cetraria (s. Lichens). 
 
 Cetraricacid 839 
 
 Cetyl 840 
 
 Cetyl, Acetate, Benzoate, Bromide, Buty- 
 
 rate, Chloride, and Cyanide of . . 
 Cetyl, Hydrate of : Cetylic Alcohol; 
 
 Ethal 841 
 
 Cetyl, Iodide of 
 
 Cetyl, Nitride of (s. Cetylamine). 
 
 Cetyl, Oxide of: Cetylic ether 842 
 Cetyl-ethyl-oxide . . 
 Cetyl-sodium oxide. . 
 Cetyl, Stearate of . 
 Cetyl, Succinate of 
 
 Cetyl, Sulphate (acid) of: Cetyl- sulphuric 
 add 
 
 Cetyl, Sulphide of 
 
 Cetyl, Sulphydrate: Cetylic Mercaptan . 
 Ce;y la mines: 
 
 Tricetylamine 843 
 
 Cetyl-phenylamine .... 
 
 Cetyl-xanthic acid 
 
 Cevadic acid 
 
 Cevadin: Hordein 
 
 Ceylanite, or Ceylonite .... 
 
 Chabasite 
 
 Chajrophyllum 844 
 
 Chailk-tia toxicaria 
 
 Chalcanthite 
 
 Chalcedony . . . . . . 
 
 Chalcodite 
 
 Chalcolite (s. Uranite). 
 
THE FIRST VOLUME. 
 
 1133 
 
 Chalcophacite 
 
 Chalcophyllite (s. Copper mica). 
 
 Chalcopyrite (s. Copper pyrites). 
 
 Chalcostibite .... 
 
 Chalcotrichite 
 
 Chalilite 
 
 845 
 
 Chalk 
 
 Chalk stones. Chalkosin 
 
 Chalybeate waters. Chalybite 
 
 Chamacleon mineral .... 
 
 Chamaerops humilis .... 
 
 Chainoisite ...... 
 
 Chamotte 
 
 Champagne wine ..... 
 
 Chantonite 
 
 Chara foetida 
 
 Charcoal (s. Carbon, p. 759). 
 
 Chathamite 
 
 Chavica officinarum .... 
 
 Chay, or Chaya root .... 
 
 Cheese .... . . 
 
 Cheiranthus Cheiri , 
 
 Chelerythrin 
 
 Chelidonic acid 
 
 Chelidonine 
 
 Chelidoninic acid 
 
 Chelidoxanthin . , 
 
 Chemical affinity . . . ^ . 
 
 Distinctions between Chemical Com- 
 pounds, properly so called, and 
 Mixtures or Solutions : 
 
 1. As regards proportion: LAW 
 OF MULTIPLES 
 
 2. As to the character of the pro- 
 duct 
 
 3. As to the phenomena which 
 accompany the formation and 
 decomposition of chemical com- 
 pounds 
 
 Different orders of chemical com- 
 pounds ..... 
 Formation and decomposition of 
 
 chemical compounds 
 Formation of compounds by di- 
 rect union of elements 
 Formation of compounds by trans- 
 formation of previously existing 
 compounds : 
 
 i. By Heat .... 
 II. By Electricity . 
 in. By the action of another 
 substance, simple or com- 
 pound : SUBSTITUTION 
 AND DOUBLE DECOMPO- 
 SITION .... 
 Magnitude or strength of affinity . 
 Circumstances which modify the 
 strength of affinity: 
 
 1. Elasticity and Cohesion . 
 
 2. The relative quantities of 
 the acting substances 
 
 Berthollet's law 
 Bunsen's law . 
 Debus's experiments 
 Gladstone's experiments 
 Malaguti's experiments 
 Margueritte's experiments 
 H. Rose's experiments 
 Theories of chemical action 
 
 Chenocholalic acid 
 
 Chenocholic acid . 
 
 Chenocoprolite ... 
 
 Chenopodium. . . . 
 
 Chert . ... 
 
 846 
 
 847 
 
 849 
 850 
 
 851 
 
 852 
 
 853 
 854 
 
 855 
 
 858 
 859 
 
 860 
 861 
 
 863 
 
 864 
 867 
 
 868 
 
 PAGE 
 
 Chessylite (s. Carbonates of Copper, p. 784). 
 Chesterlite (s. Felspar). 
 
 Chestnut 868 
 
 Chiastolite 
 
 Chica 869 
 
 Childrenite . . . . . . 
 
 Chileite (s. Gothite). 
 
 Chiltonite (s. Prehnite). 
 
 Chinoline . . . . . . 
 
 Salts of chinoline . 87J 
 
 Methyl-chinoline . 872 
 
 Ethyl-chinoline 
 
 Amyl-chinoline . 873 
 
 Chinone. Chiolite , 
 
 Chitin 874 
 
 Chiviatite 875 
 
 Chladnite (s. Meteorites). 
 
 Chloanthite 
 
 Chlocarbethamide (syn. with Trichlo- 
 
 racetamide, p. 6). 
 Chlorocetamic acid (syn. with Tetra 
 
 chloracetamide, p. 6). 
 Chloracetic acids : 
 
 Monochloracetic acid ... 
 Trichloracetic acid .... 877 
 Chloracetones (s. Acetone, p. 29). 
 
 Chloracetonitrile 879 
 
 Chloracetyl . . . . . . 
 
 Chloracetyphide 
 
 Chloral 880 
 
 Metachloral 882 
 
 Chloral, Amylic (s. Chloramylal). 
 
 Chloral, Mesitic 
 
 Chloral, Propionic . . 
 
 Chloralbin 883 
 
 Chloraldehydes ..... 
 Chloride of trichloracetyl, or Per- 
 chlorinated acetic aldehyde . 
 
 Chloralide 884 
 
 Chloraloil 885 
 
 Chloraluric acid 
 
 Chloramylal 
 
 Chloranil 
 
 Chloranilamic acid 
 
 Chloranilamide 
 
 Chloranilammone 
 
 Chloranilic acid 
 
 Chloraniline (s. Phenylamine). 
 
 Chloranisic acid (s. Anisic acid, p. 302) 
 
 Chlorastrolite 
 
 Chlorates 
 
 Chlorates of Aluminium, Ammo- 
 nium, Barium 
 Chlorates of Cobalt, Copper, Lead, 
 Lithium, Magnesium, Manganese, 
 Mercury . .886 
 Chlorate of Nickel . . 887 
 Chlorate of Potassium . 
 Chlorate of Silver . . 889 
 Chlorate of Sodium . 
 Chlorates of Strontium Uranium, 
 
 Zinc ... .890 
 
 Chlorhydrie or Hydrochloric acid . 
 
 Chlorhydric ethers (p. 897). 
 
 Chlorhydrins 893 
 
 Chlorhydrophenide (s. Phenyl). 
 Chlorhydroproteic acid .... 894 
 Chlorides : 
 
 1. Metallic chlorides ... 
 
 2. Chlorides of Organo - metallic 
 
 radicles 896 
 
 3. Chlorides of Alcohol-radicles . 897 
 
 4. Chlorides of Aldehyde -radicles . 898 
 
 5. Chlorides of Acid-radicles . . 
 
 (see Quinone and 
 Quinonic acid). 
 
1134 
 
 INDEX TO 
 
 Chlorindatmite .... 
 Chlorindin (s. Indin). 
 Chlorine : 
 
 Antichloristic theory 
 Chlorine, Detection and Estimation of: 
 
 1. Reactions .... 
 
 2. Quantitative estimation . 
 
 3. Separation from other elements 
 
 4. Atomic weight . . 
 Chlorine, Hydrate of ... 
 Chlorine, Oxides and Oxygen-acids of 
 
 Hypochlorous acid and anhydride 
 
 Hypochlorites . . 
 Chlorous anhydride, acid, and salt 
 Chloric acid and salts 
 Perchloric acid and salts 
 Perchloric oxide and Euchlorine 
 Chlorine, Sulphides of . 
 Chloriodofonn .... 
 Chlorisamic acid and Chlorisamide (s. 
 
 Isamic acid and Isamide). 
 Chlorisatic acid (s. Isatic acid). 
 Chlorisatyde Chlorisatydic acid (s. Isa- 
 
 tyde and Isatydic acid). 
 Chlorisatin (s. Isatin). 
 Chlorisatosulphites (s. Isatosulphites). 
 
 Chlorite 
 
 Chlorite earth; Chlorite, ferrugi- 
 nous ; Chlorite-slate ; Chlorite- 
 
 spar 
 
 Chlorites 
 
 Chloritoide 
 
 Chlorobenzaldide (s. Benzoyl, Chloride 
 
 of, p. 566). 
 
 Chlorobenzamide (s. Benzamide, p. 540). 
 Chlorobenzeue (s. Benzene, p. 543). 
 
 Chlorobenzil 
 
 Chlorobenzoic acid (s. Benzdic acid, 
 
 p. 555). 
 Chlorobenzol (s. Benzvlene, Chloride of, 
 
 p. 597). 
 Chlorobenzonitrile (s. Benzonitrile. p. 
 
 563). 
 
 Chlorobenzophenide (p. 554). 
 Chlorobenzoyl, Chloride of (567). 
 
 Chlorocaffeine 
 
 Chlorocamphene (s. Camphene, p. 724). 
 Chlorocarbo-hyposulphuric acid, syn. 
 
 with Trichloro-methylsulphurous acid 
 
 (see Methyl). 
 
 Chlorocarbonic acid (p. 774). 
 Chlorocarbonic ethers .... 
 Chlorocerotic acid (s. Cerotic acid, p. 
 
 887). 
 Chlorocinnamic acid (see. Cinnamie 
 
 acid). 
 
 Chlorocinnose (s. Cinnamyl). 
 Chlorochloric acid ..... 
 Chlorocomenic acid (s. Comenic acid). 
 Chlorocumene (see Cumene). 
 Chlorocuminol (s. Cuminol). 
 
 PAGE 
 
 900 
 
 902 
 903 
 
 904 
 906 
 
 907 
 908 
 909 
 910 
 
 912 
 913 
 
 914 
 915 
 
 916 
 
 Chlorodraconesic acid (syn. with Chlora- 
 
 nisic acid. See Anisic acid, p. 302). 
 
 Chlorodraconyl 917 
 
 Chloroenanthic acid (s. (Enanthic acid). 
 Chloroform ...... 
 
 Solubility of alkaloids in chloroform 919 
 Chloroformyf-hyposulphuric acid (syn. 
 
 with Dichloromethylsulphurous acid. 
 
 See Methyl). 
 Chlorogenic acid (s. Caffetannic acid, p. 
 
 709). 
 
 PAGE 
 
 Chlorogenin 920 
 
 Chloromelal 
 
 Chloromelane (s. Cronstedtite). 
 Chloromelaniline (s. Melaniline). 
 
 Chloromercurates 
 
 Chloromesitate of Methylene . . 
 
 Chloromethylase 
 
 Chloronapthane (s. Naphthalene). 
 Chloronaphthalic acid (s. Naphthalene, 
 Chlorine-derivatives of). 
 
 Chloroniceic acid 
 
 Chloropal 
 
 Chloropalladates 
 
 Chloropalladites . . . '. . 
 Chloropalmitic acid (s. Palmitic acid). 
 Chloroperchloric acid .... 
 
 Chlorophaeite 922 
 
 Chlorophaenerite 
 
 Chlorophane 
 
 Chlorophenesic acid \ 
 
 Chlorophenisic acid [ (s. Phenic acid). 
 
 Chlorophenusic acid J 
 
 Chlorophenyl 
 
 Chlorophosphide of Nitrogen (s. Nitro- 
 gen). 
 
 Chlorophyll 
 
 Chlorophyllite 
 
 Chloropicrin 923 
 
 Bromopicrin 
 
 Chloroplatinates 
 
 Chloroplatinites 
 
 Chlororhodates 
 
 Chlororubin (s. Rubin and Madder). 
 Chlorosalicin (s. Salicin). 
 Chlorosaligenin (s. Saligenin). 
 Chlorosamide (syn. with Hydride of 
 Chlorosalicyl ; s. Salicyl). 
 
 Chlorospinel 
 
 Chlorostrychnine (s. Strychnine). 
 Chlorostyracin (s. Styracin). 
 
 Chlorosuccic acid 924 
 
 Chlorosuccinimide (s. Succinimide). 
 Chlorosulphuric acid (s. Sulphury 1, Chlo- 
 ride of). 
 
 Chloroterebene (s. Terebene). 
 Chlorovalerisic and Chlorovalerosic acids 
 
 (s. Valeric acid) 
 
 Chloroxalovinic acid (s. Oxalic ethers). 
 Chloroxamethane (s. Oxamic ethers). 
 Chloroxethide (s. Oxalic ethers). 
 
 Chloroxethose 
 
 Chloroxynaphthalic acid (s. Oxvnaph- 
 thalic acid). 
 
 Chochoca 
 
 Chodneffite (s. Cryolite). 
 
 Cholacrol 
 
 Cholalic acid 
 
 Choleic acid 
 
 Cholesteric acid 
 
 Cholesterin 925 
 
 Cholestrophane 926 
 
 Cholic acid ...... 
 
 Cholochrome 927 
 
 Cholochromic acid 928 
 
 Choloulanic acid 929 
 
 Choloi'dic acid 
 
 Cholonic acid 
 
 Chondrin ...... 930 
 
 Chondrodite 
 
 Chondrojren . . . . . . 
 
 Chondro'ites 
 
 Chonicrite 
 
 Chrismatin . . . . 
 
 Christianite (s. Phillipsite). 
 
THE FIRST VOLUME. 
 
 1135 
 
 PAGE 
 
 Chromates 930 
 
 Chromates of Ammonium . . 932 
 Chromate of Barium ... 
 Chromate of Bismuth ... 
 Chromate of Cadmium . . .933 
 Chromate of Calcium. ... 
 Chromate of Calcium and Potas- 
 sium 
 
 Chromate of Cerium ... 
 Chromate of Chromium ... 
 Chromate of Cobalt ... 
 Chromates of Copper . . . 
 Ammonio-chromate ... 
 Chromate of Copper and Potas- 
 sium . ... 
 Chromate of Glucinum 
 Chromate of Iron . . . . 
 Chromates of Lead : 
 
 Neutral chromate ... 
 Di-basic chromate . . . 934 
 Sesquibasic chromate . . 
 Chromate of Lead and Copper . 
 Chromates of Lithium, Magnesium, 
 Manganese, Mercury, Molyb- 
 denum, Nickel .... 935 
 Chromates of Potassium . . . 936 
 Neutral chromate . . . 937 
 Acid chromate .... 
 Hyperacid chromate - 
 Chromate of Potassium and Am- 
 monium ..... 938 
 Chromate of Potassium with Mer- 
 curic chloride 
 Chromate of Potassium with Mer- 
 curic cyanide ... . . 
 Chromochloride of Potassium . 
 Chromates of Silver ... 
 Ammonio-chromate ... 
 Chromates of Sodium, Strontium, 
 
 Tin, and Uranium ... 
 
 Chromates of Vanadium and Yttrium 939 
 
 Chromates of Zinc .... 
 
 Ammonio-chromate ... 
 
 Chromate of Zinc and Potassium 
 
 Chrome-alum . - 
 
 Chrome-green . . . 
 
 Chrome-iron ore . . . . 
 
 Chrome-mica 940 
 
 Chrome-ochre 
 
 Chrome- red and Chrome-yellow . . 
 
 Chromite (s. Chrome-iron ore). 
 
 Chromites (p. 950). 
 
 Chromium . ... . . . 
 
 Chromium, Bromides of . . . . 941 
 
 Chromium, Chlorides of: 
 
 Protochloride 
 
 Sesquichloride 942 
 
 Chromium, Detection and Estimation of: 
 
 1. Blowpipe reactions . . 943 
 
 2. Reactions in solution . . 
 
 3. Quantitative estimation . 944 
 
 4. Separation from other elements 
 
 5. Valuation of Chrome- ores . 945 
 
 6. Atomic weight of Chromium 946 
 Chromium, Fluorides of: 
 
 Sesquifluoride 
 
 Trifluoride 947 
 
 Chromium, Iodides of . . 
 
 Chromium, Nitride of . . 
 
 Chromium, Oxides of: 
 
 Protoxide, or Chromous oxide 
 
 Chromoso-chromic oxide . 918 
 Sesquioxide, or Chromic oxide 
 
 Chromic hydrates . . 949 
 
 PAGE 
 
 Chromium, Oxides of: 
 
 Chromic salts .... 950 
 
 Chromites .... 
 Compounds of Chromic oxide 
 
 with Ammonia . . . 
 Brown oxides of Chromium, or 
 
 Chromates of Chromium . . 951 
 
 Trioxide, or Chromic anhydride . 952 
 
 Chromic acid .... 
 
 Perchromic acid . . . . 953 
 
 Chromium, Oxychlorides of . . . 
 
 a. Compounds of sesquioxide and 
 
 sesquichloride of chromium . 
 
 b Chlorochromic anhydride . . 954 
 
 Chromium, Oxygen-salts of . . . 
 
 Chromium, Phosphide of ... 
 
 Chromium, Sulphides of. . . . 
 Chromotartaric acid . . . .955 
 Chromule (syn. with Chlorophyll). 
 
 Chryiodine 
 
 Chrysamide ...... 
 
 Chrysamidic acid 
 
 Chrysammic acid ..... 
 
 Chrysanilic acid 957 
 
 Chrysanisic acid ..... 
 
 Chrysanthemum segetum . 
 
 Chrysatric acid . . . . . 
 
 Cbrysene 958 
 
 Chrysocoll 
 
 Chrysoharmine (syn. with Nitroharmine). 
 
 Chrysolepic acid (syn. with Picric acid). 
 
 Chrysolite 
 
 Chrysophane (s. Clintonite). 
 
 Chrysophanic acid 
 
 Chrysoprase 960 
 
 Chrysoprase earth (s. Pimelite) 
 Chrysorhamnin. Chrysotile . . 
 
 Chulariose 
 
 Chusite (s. Olivine). 
 
 Chyle ....... 
 
 Chyme 962 
 
 Chymosin 
 
 Chytophyllite 
 
 Cbytostilbite 
 
 Cibotium ...... 
 
 Cicer 
 
 Cichorium 
 
 Cicutine 963 
 
 Cider 
 
 Cimicicacid 964 
 
 Cimmol (s. Cinnamyl, Hydride of, p. 990). 
 
 Cimmyl 
 
 Cimolite. ...... 
 
 Cinacrol. ...... 965 
 
 Cinaebene ...... 
 
 Cinsephane, Cinaephene, Cinaephono . 
 Cinchona barks : 
 
 Occurrence ..... 
 
 Varieties 966 
 
 Composition 
 
 Reactions 967 
 
 Estimation of Alkaloids . . .968 
 
 Cinchona- red 969 
 
 Cinchona-tannic acid (s. Quinotannic 
 acid). 
 
 Cinchonetine 971 
 
 Cinchonicine ...... 
 
 Cinchonidine 
 
 Salts of Cinchonidine . . .972 
 Methyl-cinchonidine . . . 973 
 
 Cinchonine 
 
 Beta-cinchonine . . . .974 
 Salts of Cinchonine . . . .975 
 
1136 
 
 INDEX TO THE FIRST VOLUME. 
 
 Cinchonine : 
 
 Brominated and Chlorinated Deri- 
 vates of Cinchonine : 
 Bromocinchonine 
 Sesqui-bromocinchonine . 
 Dibromocinchonine . 
 Dichlorociuchonine . 
 lodocinchonine . 
 Derivatives of Cinchonine contain 
 
 ing Organic Radicles : 
 Benzoyl-cinchonine . . 
 Methyl-cinchonine . 
 
 Cinchovatine 
 
 Cinnabar (s. Mercury). 
 Cinnamein 
 
 PAGE 
 
 978 
 
 979 
 
 980 
 
 Cinnamene, or Styrol . . . .981 
 
 Metaciunamene .... 982 
 
 Bromide of einnamene ... 
 
 Nitrocinnamene ... 983 
 
 Ginnamic acid. - . . . . . 
 
 Cinnamates ... . . 985 
 Cinnamic ethers : 
 
 Cinnamate of Ethyl . . .986 
 
 Cinnamate of Methyl . . 
 
 Cinnaraate of Cinnyl ; Styracin 
 
 Bromocinnamic acid . . . 987 
 
 Chlorocinnaraic acid ... 
 
 Nitroeinnamic acid .... 
 
 Nitrocinnamic ethers . . 988 
 
 Cinnamic alcohol (s. Cinnylic alcohol, 
 
 p. 992). 
 Cinnamic aldehyde (s. Cinnamyl, Hydride 
 
 of, p. 990). 
 
 Cinnamic anhydride . . 989 
 
 Nitrocinnamic anhydride 
 Cinnamide .... 
 Nitrocinnamide 
 Phenyl-cinnamide . 
 Nitranisyl-cinnamide, or Cinnitra 
 
 nisidine 
 
 Cinnanilide (s. Cinnamide). 
 
 Cinnhydramide . . . . . 
 
 Cinnamon, Oil of, and Oil of Cassia . 
 
 Resins from cinnamon oil . . 990 
 
 Cinnamon-stone , 
 
 Cinnamyl ...... 
 
 Cinnamyl, Chloride of . . . 
 
 Cinuamyl, Cyanide of . . . . 
 
 Cinnamyl, Hydride of . . . . 
 
 Compound with Hydrochloric acid . 991 
 Compound with Iodine and Iodide 
 
 of potassium .... 
 
 Compound with Nitric acid . . 
 Compounds with Acid sulphites of 
 
 alkali-metals . . . . 
 
 Hydride of Tetrachloro-cinnamyl . 992 
 
 Cinnyl . 
 
 Cinnylic alcohol ; Styrone ... 
 
 Cipolino ... . . . 
 
 Cissampeline (s. Pelosine). 
 Citraconamides and Citraconanilides (s. 
 
 Citraconic acid, Amides of). 
 
 Citraconic acid ..... 992 
 
 Citraconates 993 
 
 Citraconic acid, Amides of: 
 
 Citraconamide .... 
 
 Citraconimide . . . 
 
 Phenylcitraconimide, or Citra- 
 
 conanil ..... 
 
 lodophenylcitraconimide . . 
 
 Dinitrophenylcitraconimide . 
 
 Citraconamic acid .... P94 
 
 Phenyleitraconamic and Dini- 
 
 trophenylcitraconamic acid . 
 
 PAGE 
 
 Citraconic anhydride .... 994 
 Citraconic, or Pyrocitric chloride . . 
 Citraconic ether (p. 993). 
 Citramides (p. 1000). 
 Citraconimide (p. 993). 
 Citraconiodanil (syn with lodophenyl- 
 citraconimide, (p. 993). 
 
 Citrene 
 
 Citric acid .... 
 
 Citrates .... 997 
 
 Oxvchlorocitric acid 
 Citric acid, Amides of . . 1000 
 
 Citramide ... 
 
 Phenylcitramide 
 
 Phenylcitrimide 
 
 Phenylcitramic acid 
 
 Diphenylcitramic acid . 
 Citric ethers ...... 
 
 Citrates of methyl .... 1001 
 
 Citrate of ethyl .... 
 Citridic acid (s. Aconitic acid, p. 54). 
 Citrilene (s. Citrene, p. 994). 
 
 Citrin 
 
 Citrins .......- 
 
 Citroceric and Citrolic acids 
 
 Citrobianil, or Citrodianil (s. Citric acid, 
 
 Amides of) 
 Citrobianilic or Citrodianilic acid (s. 
 
 Citric acid, Amides of, p 1000). 
 Citroglycerin (s. Citrins). 
 Citromannitans ..... 
 
 Citron, Oil of (s. Citrus medica, p. 1004). 
 
 Citrus Aurantium 1002 
 
 Citrus Bergamia 1003 
 
 Citrus Bigaradia 
 
 Citrus Limetta 
 
 Citrus Limonum ..... 
 
 Oil of Lemon 
 
 Hydrate of Lemon-oil . .1004 
 
 Hydrochlorates of Lemon-oil . 
 
 Lemon-camphor, or Citroptene 
 
 Citrus Lumia ...... 1005 
 
 Citrus medica 1006 
 
 Citryl ....... 
 
 Civet 
 
 Clarification 1007 
 
 Classification . . . . . 
 
 Clausthalite 1023 
 
 Clay 
 
 Clay-slate 1025 
 
 Clfly iron-stone 
 
 Clayite 
 
 Cleavage of Crystals .... 
 
 Cleavlandite 
 
 Cleophane ...... 
 
 Clematis-camphor ..... 
 
 Clematitin 
 
 Clingmannite (s. Margarite). 
 
 Clinkstone ...... 
 
 Clinochlore 
 
 Clinoclase (s. Abichite). . . . 1026 
 
 Clintonite 
 
 Clouds 
 
 Cloves, Oil of. ..... 1029 
 
 Clovorubrin 
 
 Club-moss (s. Lycopodium). 
 
 Cluthalite 
 
 Cnicin 
 
 Coagulum ... . . 
 
 Coal 
 
 Coal-gas 1035 
 
INDEX TO THE FIRST VOLUME. 
 
 1137 
 
 1051 
 
 1054 
 1055 
 1056 
 
 PAGE 
 
 Cobalt ....... 1039 
 
 Cobalt, Alloys of ..... 1041 
 Cobalt, Bromide of ..... 
 Cobalt, Chlorides of .... 
 Cobalt, Detection and Estimation of: 
 
 1. Blowpipe reactions . . . 1042 
 
 2. Reactions in solution . . 
 
 3. Quantitative estimation . . 1044 
 
 4. Separation from other elements . 1045 
 
 5. Valuation of Cobalt-ores . . 1048 
 
 6. Atomic weight of Cobalt . . 
 Cobalt, Earthy ..... 
 Cobalt, Fluoride of . 
 Cobalt, Iodide of ..... 
 Cobalt, Oxides of . 
 
 Cobalt, Oxysulphide of . . 1050 
 
 Cobalt, Oxygen- salts of 
 
 Cobalt, Phosphides of 
 
 Cobalt, red . 
 
 Cobalt, Selenide of . 
 
 Cobalt, Sulphides of 
 
 Cobalt-bases, Ammoniacal 
 
 Diammonio-cobaltic salts . . 
 
 Triammonio-cobaltic salts . . 
 
 Tetrammonio-cobaltic or Fusco-co- 
 baltic salts . . . . . 
 
 Pentammonio-cobaltic (Roseo- and 
 Purpureo-cobaltic) salts . . 1052 
 
 Nitroso - pentammonio - cobaltic or 
 Xantho-cobaltic salts . . . 
 
 Hexammonio- cobaltic or Luteo-co- 
 baltic salts ..... 
 
 Ammonio-percobaltic or Oxycobal- 
 tic salts ..... 
 
 General formula? of the Ammonia- 
 
 cal Cobalt-compounds ... 
 Cobalt-bloom ...... 1057 
 
 Cobalt-blue . .... 
 
 Cobalt-glance (s. Cobaltine). 
 
 Cobalt green ...... 
 
 Cobaltine ....... 
 
 Cobalt-mica (s. Cobalt-bloom). 
 Cobalt-pyrites (s. Cobalt, sulphides of). 1058 
 Cobalt-vitriol ...... 
 
 Cobalt-yellow ..... 
 
 Coca. Cocaine ..... 1059 
 
 id HCoca . . . 106 
 
 Coccin. Coccinite ..... 
 
 ( occinnic acid. Coccmonic acid . . 
 
 Coccodea viridis ..... 
 
 Coccognic acid ..... 
 
 Coccolite ...... 
 
 Coccoloba ...... 
 
 Cocculin (s. Picrotoxin). 
 
 Cocculus indicus ..... 
 
 Coccusic acid ...... 
 
 Cochineal ...... 
 
 Cochineal-red ..... 1062 
 
 Cochlearia. Cochlearin . . . . 1063 
 
 Cocinic acid . 
 
 Cocinin .... 
 
 Cocinone 
 
 Cocoa-nut oil . 
 
 Codeine ....... 1< 
 
 Salts of Codeine .... 1065 
 
 Substitution-products : 
 
 Bromocodeine . . 1066 
 
 Tribromocodeine ... 1067 
 Chlorocodeine 
 
 PAGE 
 
 Codeine 
 
 Substitution-products : 
 Cyanocodeine 1068 
 
 Ethylcodeine 
 lodocodeine 
 Nitrocodeine 
 ocelestin . . 1069 
 
 Ccelocline . . . . . . 
 
 Coerulic acid ...... 
 
 Ccerulin 
 
 Coffee 
 
 Coffee-leaves 1075 
 
 Coffeine (s. Caffeine). 
 
 Cognac 1076 
 
 Cohobation ...... 
 
 Cohesion and Adhesion . . . . 
 
 olchiceine ...... 1080 
 
 Colchicine ...... 
 
 Colchicum 1081 
 
 Colcothar 1082 
 
 Colletiin 
 
 Collidine 
 
 Ethyl-collidine .... 1083 
 
 Collinic acid 
 
 Collinic aldehyde ..... 
 Collodion ......-_ 
 
 Collyl, Hydride of 1084= 
 
 Collyrite 
 
 Colocynthin ...... 
 
 Colocynthitin 1085 
 
 Colombic acid. Colombia ... 
 
 Colombo root 1086 
 
 Colophane. Colophene. Colophilene . 
 
 Colopholic acid 1087 
 
 Colophonic acids 
 
 Colophonite 
 
 Colophonone 
 
 Colophony 
 
 Colorimeter 1088 
 
 Colorin 
 
 Colostrum .... 
 
 Colour. Colouring matters . 1088 
 
 Columbite. Columbium . 1089 
 
 Combustion .... 
 
 Conditions of Inflammability 1094 
 
 Nature of flame . . 1096 
 
 Causes which modify and extinguish 
 combustion . . . . .1100 
 
 Comenamethane H02 
 
 Comenamic acid 
 
 Comenic acid 1103 
 
 Comenates 1H>4 
 
 Bromocomenic acid 1105 
 
 Chlorocomenic acid 
 Ethylcomenic acid 
 
 Comptonite 
 
 Concentration 
 
 Conchiolin 
 
 Concretions, Animal 
 
 Condensation 
 
 Condrodite (s. Chondrodite). 
 
 Condurrite . . . 
 
 Conglomerate 
 
 1106 
 1107 
 
 1110 
 
 ADDENDA. 
 
 Acetylene 1111 
 
 Allylene 1112 
 
 Ca3sium . . .... 
 
 END OF THE FIEST VOLUME. 
 
 VOL. I. 
 
 4 D 
 
LONDON 
 
 PRINTED BY SPOTTISWOODK AND CO. 
 NEW-STJIEKT 6QUARB 
 
WATTS'S DICTIONARY OF CHEMISTRY. 
 
 In course of publication in Monthly Parts, in medium 8vo. now ready, 
 
 VOL. I. price 31s. 6d. VOL. II. price 26s. VOL. III. price 31s. Qd. 
 
 and VOL. IV. price 24s. to be completed in Five Volumes, 
 
 A DICTIONARY 
 
 OF 
 
 CHEMISTRY 
 
 AND THE 
 
 ALLIED BRANCHES OF OTHER SCIENCES. 
 
 Founded on that of the late DR. URE. 
 
 HEKRY WATTS, B.A. F.C.S. 
 
 EDITOQ OF 'THE JOURNAL OF THE CHEMICAL SOCIETY'; ASSISTED BY EMIKBNT OONTBIBTTTORS. 
 
 THIS work was originally intended as a New Edition of UEE'S Dictionary of Che- 
 mistry and Mineralogy ; but the great changes made in chemical science since the 
 publication of the last edition of that Dictionary (1831) changes, not merely con- 
 sisting in the addition of new discoveries, but involving a complete revolution in the 
 mode of viewing and expressing chemical reactions have rendered it almost impossible 
 to adapt any matter written so long ago to the existing requirements of the science. 
 The present must therefore be regarded as essentially a new work, in which only a few 
 articles of UBE'S Dictionary are retained, chiefly of a descriptive character. In com- 
 piling it, the Editor has freely availed himself of the stores of information in GMELIN'S 
 * Handbook,' GEEHABDT'S ' Chimie Organique,' ROSES' s ' Trait6 d' Analyse Chimique,' 
 DANA'S 'Mineralogy,' RAMMELSBEBG'S ' Mineral-chemie,' the ' Handworterbuch der 
 Chemie,' &c. ; and has endeavoured, by careful consultation of original memoirs, to 
 bring the treatment of each subject down to the present time. He has also been 
 fortunate in obtaining the co-operation of several chemists of acknowledged ability and 
 eminence, who have kindly contributed articles on subjects to which they have paid 
 special attention. The List of their names is as follows : 
 
 EDMTTND ATKINSON, Ph.D. F.C.S. Pro- 
 fessor of Chemistry at the Royal Mili- 
 tary College, Sandhurst. 
 
 FBANCIS T. CONINGTON, M.A. F.C.S. (the 
 late) Fellow of Corpus Christi College, 
 Oxford, and Examiner in Natural 
 Science at that University ; Author of 
 a ' Handbook of Chemical Analysis.' 
 
 WILLIAM DITTMAB, Esq. Principal Assist- 
 ant in the Chemical Laboratory of the 
 University of Edinburgh. 
 
 FBEDEBICK FIELD, F.R.S. F.R.S.E. (lately) 
 Professor of Chemistry at St. Mary's 
 Hospital. 
 
 GEOBGE C. FOSTEH, B.A. F.C.S. Professor 
 of Experimental Physics at University 
 College, London. 
 
 MICHAEL FOSTER, M.D. Huntingdon. 
 
 EDWAED FRANKLAND, Ph.D. F.R.S. 
 Foreign Secretary of the Chemical 
 Society ; Professor of Chemistry at the 
 Royal Institution of Great Britain, and 
 at the Royal School of Mines. 
 
 FEEDEEICK GUTHBIE, Ph.D. F.C.S. Pro- 
 fessor of Chemistry at the Royal College, 
 Mauritius. 
 
 M. L'ABBE A. HAMT, Paris. 
 
 MICHAEL HANHAET, Esq. Lithographer. 
 
 A. W. HOFMANN, LL.D. F.R.S. V.P.C.S. 
 Professor of Chemistry at the Univer- 
 sity of Berlin. 
 
 WILLIAM S. JEVONS, M.A. (lately) Gold 
 Assayer in the Sydney Royal Mint. 
 
 CHAELES E. LONG, Esq. F.C.S. (the late) 
 Analytical Chemist. 
 
 [Continued. 
 
WATTS'S DICTIONARY OF CHEMISTRY. 
 
 LIST OP CONTRIBUTORS continued. 
 
 WILLIAM ODLING, M.B. F.R.S. Secretary 
 to the Chemical Society, and Professor 
 of Chemistry at St. Bartholomew's 
 Hospital, Author of a 'Manual of 
 Chemistry.' 
 
 BENJAMIN H. PAUL, Ph.D. F.C.S. Con- 
 sulting Chemist. 
 
 THOMAS RICHARDSON, Ph.D. F.R.S. &c. 
 Reader in Chemistry at the University 
 of Durham. 
 
 HENRY E. ROSCOE, Ph.D. F.R.S. F.C.S. 
 Professor of Chemistry at Owens 
 College, Manchester. 
 
 WILLIAM J. RUSSELL, Ph.D. F.C.S. of 
 University College, London. 
 
 J. A. WANKLY.V, F.R.S.E. F.C.S. Pro- 
 fessor of Chemistry at the London 
 Institution. 
 
 C. G-REVILLE WILLIAMS, F.R.S. Author 
 of a ' Handbook of Chemical Manipu- 
 lation.' 
 
 ALEXANDER W.WILLIAMSON, Ph.D. F.R.S. 
 V.P.C.S. Professor of Chemistry at 
 University College, London, and Exa- 
 miner in Chemistry at the University 
 of London. (A. W. W.) 
 
 ARTHUR WINCKLER WILLS, Esq. Ana- 
 lytical and Manufacturing Chemist, 
 Wolverhampton. (W. W.) 
 
 The work is essentially a Dictionary of Scientific Chemistry, and is intended as a 
 Companion to the New Edition of URE'S Dictionary of Arts, Manufactures, and Mines, 
 to which therefore reference is, for the most part, made for the details of manufactur- 
 ing operations ; but those branches of chemical manufacture which have come into 
 existence, or have received important developments, since the publication of that work, 
 are described in this Dictionary as fully as its limits will allow, and in all cases ex- 
 planations are given of the principles on which manufacturing processes are conducted, 
 and the chemical changes which they involve. Particular attention has also been given 
 to the description of processes of Analysis, both qualitative and quantitative. 
 
 In order that the work may, as far as possible, truly represent the present state of 
 scientific chemistry, it has been found absolutely necessary to make the modern or 
 ' unitary ' scale of atomic weights the basis of the system of notation and mode of 
 exposition adopted. Especial care has, however, been taken that the treatment of all 
 Articles which are likely to be consulted, for the sake of practical information, by 
 manufacturers, or others not exclusively occupied in chemical pursuits, shall be such 
 as to make them readily intelligible to all who possess a general knowledge of che- 
 mistry, though they may not have followed closely the recent developments of the 
 theoretical parts of the science. Hence, in all such Articles (as ACETIC ACID, ANTI- 
 MONY, COPPER, &c.) the formulae are given according to the old notation, as well as 
 according to that adopted in the rest of the work. 
 
 The Dictionary was at first intended to consist of 3,000 pages, making Three 
 Volumes ; but, as the work has advanced, these limits have been found too narrow to 
 include the vast and continually increasing store of facts with which the science of 
 Chemistry is enriched, without sacrificing in the latter portion of the work that ful- 
 ness of detail which, to judge from recent criticism, appears to be regarded as one of 
 its most useful characteristics. It has, therefore, been resolved to extend the work to 
 FIVE VOLUMES. With this extension, it is hoped that the Dictionary will afford a 
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 1 Mr. WATTS'S Dictionary is already 
 recognised as the standard English work 
 on Chemistry.' DUBLIN MEDICAL PRESS. 
 
 ' THE English L tnguage is not rich in 
 lexicons of science : we would point to 
 this work as a model upon which others 
 might be framed. It certainly exhausts 
 the subject up to the date of publication, 
 and therefore forms as it were the 
 balanced ledger of the chemist. To the 
 practical analyst this work must prove 
 of the utmost value, -to the philosophi- 
 cal investigator it must, as the record of 
 
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 to the student who is true to his studies, 
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